diff options
Diffstat (limited to 'vendor/honnef.co/go')
56 files changed, 20384 insertions, 0 deletions
diff --git a/vendor/honnef.co/go/tools/LICENSE b/vendor/honnef.co/go/tools/LICENSE new file mode 100644 index 0000000..dfd0314 --- /dev/null +++ b/vendor/honnef.co/go/tools/LICENSE @@ -0,0 +1,20 @@ +Copyright (c) 2016 Dominik Honnef + +Permission is hereby granted, free of charge, to any person obtaining +a copy of this software and associated documentation files (the +"Software"), to deal in the Software without restriction, including +without limitation the rights to use, copy, modify, merge, publish, +distribute, sublicense, and/or sell copies of the Software, and to +permit persons to whom the Software is furnished to do so, subject to +the following conditions: + +The above copyright notice and this permission notice shall be +included in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND +NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE +LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION +WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. diff --git a/vendor/honnef.co/go/tools/callgraph/callgraph.go b/vendor/honnef.co/go/tools/callgraph/callgraph.go new file mode 100644 index 0000000..d93a20a --- /dev/null +++ b/vendor/honnef.co/go/tools/callgraph/callgraph.go @@ -0,0 +1,129 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +/* + +Package callgraph defines the call graph and various algorithms +and utilities to operate on it. + +A call graph is a labelled directed graph whose nodes represent +functions and whose edge labels represent syntactic function call +sites. The presence of a labelled edge (caller, site, callee) +indicates that caller may call callee at the specified call site. + +A call graph is a multigraph: it may contain multiple edges (caller, +*, callee) connecting the same pair of nodes, so long as the edges +differ by label; this occurs when one function calls another function +from multiple call sites. Also, it may contain multiple edges +(caller, site, *) that differ only by callee; this indicates a +polymorphic call. + +A SOUND call graph is one that overapproximates the dynamic calling +behaviors of the program in all possible executions. One call graph +is more PRECISE than another if it is a smaller overapproximation of +the dynamic behavior. + +All call graphs have a synthetic root node which is responsible for +calling main() and init(). + +Calls to built-in functions (e.g. panic, println) are not represented +in the call graph; they are treated like built-in operators of the +language. + +*/ +package callgraph // import "honnef.co/go/tools/callgraph" + +// TODO(adonovan): add a function to eliminate wrappers from the +// callgraph, preserving topology. +// More generally, we could eliminate "uninteresting" nodes such as +// nodes from packages we don't care about. + +import ( + "fmt" + "go/token" + + "honnef.co/go/tools/ssa" +) + +// A Graph represents a call graph. +// +// A graph may contain nodes that are not reachable from the root. +// If the call graph is sound, such nodes indicate unreachable +// functions. +// +type Graph struct { + Root *Node // the distinguished root node + Nodes map[*ssa.Function]*Node // all nodes by function +} + +// New returns a new Graph with the specified root node. +func New(root *ssa.Function) *Graph { + g := &Graph{Nodes: make(map[*ssa.Function]*Node)} + g.Root = g.CreateNode(root) + return g +} + +// CreateNode returns the Node for fn, creating it if not present. +func (g *Graph) CreateNode(fn *ssa.Function) *Node { + n, ok := g.Nodes[fn] + if !ok { + n = &Node{Func: fn, ID: len(g.Nodes)} + g.Nodes[fn] = n + } + return n +} + +// A Node represents a node in a call graph. +type Node struct { + Func *ssa.Function // the function this node represents + ID int // 0-based sequence number + In []*Edge // unordered set of incoming call edges (n.In[*].Callee == n) + Out []*Edge // unordered set of outgoing call edges (n.Out[*].Caller == n) +} + +func (n *Node) String() string { + return fmt.Sprintf("n%d:%s", n.ID, n.Func) +} + +// A Edge represents an edge in the call graph. +// +// Site is nil for edges originating in synthetic or intrinsic +// functions, e.g. reflect.Call or the root of the call graph. +type Edge struct { + Caller *Node + Site ssa.CallInstruction + Callee *Node +} + +func (e Edge) String() string { + return fmt.Sprintf("%s --> %s", e.Caller, e.Callee) +} + +func (e Edge) Description() string { + var prefix string + switch e.Site.(type) { + case nil: + return "synthetic call" + case *ssa.Go: + prefix = "concurrent " + case *ssa.Defer: + prefix = "deferred " + } + return prefix + e.Site.Common().Description() +} + +func (e Edge) Pos() token.Pos { + if e.Site == nil { + return token.NoPos + } + return e.Site.Pos() +} + +// AddEdge adds the edge (caller, site, callee) to the call graph. +// Elimination of duplicate edges is the caller's responsibility. +func AddEdge(caller *Node, site ssa.CallInstruction, callee *Node) { + e := &Edge{caller, site, callee} + callee.In = append(callee.In, e) + caller.Out = append(caller.Out, e) +} diff --git a/vendor/honnef.co/go/tools/callgraph/static/static.go b/vendor/honnef.co/go/tools/callgraph/static/static.go new file mode 100644 index 0000000..5444e84 --- /dev/null +++ b/vendor/honnef.co/go/tools/callgraph/static/static.go @@ -0,0 +1,35 @@ +// Package static computes the call graph of a Go program containing +// only static call edges. +package static // import "honnef.co/go/tools/callgraph/static" + +import ( + "honnef.co/go/tools/callgraph" + "honnef.co/go/tools/ssa" + "honnef.co/go/tools/ssa/ssautil" +) + +// CallGraph computes the call graph of the specified program +// considering only static calls. +// +func CallGraph(prog *ssa.Program) *callgraph.Graph { + cg := callgraph.New(nil) // TODO(adonovan) eliminate concept of rooted callgraph + + // TODO(adonovan): opt: use only a single pass over the ssa.Program. + // TODO(adonovan): opt: this is slower than RTA (perhaps because + // the lower precision means so many edges are allocated)! + for f := range ssautil.AllFunctions(prog) { + fnode := cg.CreateNode(f) + for _, b := range f.Blocks { + for _, instr := range b.Instrs { + if site, ok := instr.(ssa.CallInstruction); ok { + if g := site.Common().StaticCallee(); g != nil { + gnode := cg.CreateNode(g) + callgraph.AddEdge(fnode, site, gnode) + } + } + } + } + } + + return cg +} diff --git a/vendor/honnef.co/go/tools/callgraph/util.go b/vendor/honnef.co/go/tools/callgraph/util.go new file mode 100644 index 0000000..7aeda96 --- /dev/null +++ b/vendor/honnef.co/go/tools/callgraph/util.go @@ -0,0 +1,181 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package callgraph + +import "honnef.co/go/tools/ssa" + +// This file provides various utilities over call graphs, such as +// visitation and path search. + +// CalleesOf returns a new set containing all direct callees of the +// caller node. +// +func CalleesOf(caller *Node) map[*Node]bool { + callees := make(map[*Node]bool) + for _, e := range caller.Out { + callees[e.Callee] = true + } + return callees +} + +// GraphVisitEdges visits all the edges in graph g in depth-first order. +// The edge function is called for each edge in postorder. If it +// returns non-nil, visitation stops and GraphVisitEdges returns that +// value. +// +func GraphVisitEdges(g *Graph, edge func(*Edge) error) error { + seen := make(map[*Node]bool) + var visit func(n *Node) error + visit = func(n *Node) error { + if !seen[n] { + seen[n] = true + for _, e := range n.Out { + if err := visit(e.Callee); err != nil { + return err + } + if err := edge(e); err != nil { + return err + } + } + } + return nil + } + for _, n := range g.Nodes { + if err := visit(n); err != nil { + return err + } + } + return nil +} + +// PathSearch finds an arbitrary path starting at node start and +// ending at some node for which isEnd() returns true. On success, +// PathSearch returns the path as an ordered list of edges; on +// failure, it returns nil. +// +func PathSearch(start *Node, isEnd func(*Node) bool) []*Edge { + stack := make([]*Edge, 0, 32) + seen := make(map[*Node]bool) + var search func(n *Node) []*Edge + search = func(n *Node) []*Edge { + if !seen[n] { + seen[n] = true + if isEnd(n) { + return stack + } + for _, e := range n.Out { + stack = append(stack, e) // push + if found := search(e.Callee); found != nil { + return found + } + stack = stack[:len(stack)-1] // pop + } + } + return nil + } + return search(start) +} + +// DeleteSyntheticNodes removes from call graph g all nodes for +// synthetic functions (except g.Root and package initializers), +// preserving the topology. In effect, calls to synthetic wrappers +// are "inlined". +// +func (g *Graph) DeleteSyntheticNodes() { + // Measurements on the standard library and go.tools show that + // resulting graph has ~15% fewer nodes and 4-8% fewer edges + // than the input. + // + // Inlining a wrapper of in-degree m, out-degree n adds m*n + // and removes m+n edges. Since most wrappers are monomorphic + // (n=1) this results in a slight reduction. Polymorphic + // wrappers (n>1), e.g. from embedding an interface value + // inside a struct to satisfy some interface, cause an + // increase in the graph, but they seem to be uncommon. + + // Hash all existing edges to avoid creating duplicates. + edges := make(map[Edge]bool) + for _, cgn := range g.Nodes { + for _, e := range cgn.Out { + edges[*e] = true + } + } + for fn, cgn := range g.Nodes { + if cgn == g.Root || fn.Synthetic == "" || isInit(cgn.Func) { + continue // keep + } + for _, eIn := range cgn.In { + for _, eOut := range cgn.Out { + newEdge := Edge{eIn.Caller, eIn.Site, eOut.Callee} + if edges[newEdge] { + continue // don't add duplicate + } + AddEdge(eIn.Caller, eIn.Site, eOut.Callee) + edges[newEdge] = true + } + } + g.DeleteNode(cgn) + } +} + +func isInit(fn *ssa.Function) bool { + return fn.Pkg != nil && fn.Pkg.Func("init") == fn +} + +// DeleteNode removes node n and its edges from the graph g. +// (NB: not efficient for batch deletion.) +func (g *Graph) DeleteNode(n *Node) { + n.deleteIns() + n.deleteOuts() + delete(g.Nodes, n.Func) +} + +// deleteIns deletes all incoming edges to n. +func (n *Node) deleteIns() { + for _, e := range n.In { + removeOutEdge(e) + } + n.In = nil +} + +// deleteOuts deletes all outgoing edges from n. +func (n *Node) deleteOuts() { + for _, e := range n.Out { + removeInEdge(e) + } + n.Out = nil +} + +// removeOutEdge removes edge.Caller's outgoing edge 'edge'. +func removeOutEdge(edge *Edge) { + caller := edge.Caller + n := len(caller.Out) + for i, e := range caller.Out { + if e == edge { + // Replace it with the final element and shrink the slice. + caller.Out[i] = caller.Out[n-1] + caller.Out[n-1] = nil // aid GC + caller.Out = caller.Out[:n-1] + return + } + } + panic("edge not found: " + edge.String()) +} + +// removeInEdge removes edge.Callee's incoming edge 'edge'. +func removeInEdge(edge *Edge) { + caller := edge.Callee + n := len(caller.In) + for i, e := range caller.In { + if e == edge { + // Replace it with the final element and shrink the slice. + caller.In[i] = caller.In[n-1] + caller.In[n-1] = nil // aid GC + caller.In = caller.In[:n-1] + return + } + } + panic("edge not found: " + edge.String()) +} diff --git a/vendor/honnef.co/go/tools/cmd/megacheck/megacheck.go b/vendor/honnef.co/go/tools/cmd/megacheck/megacheck.go new file mode 100644 index 0000000..4c0b97c --- /dev/null +++ b/vendor/honnef.co/go/tools/cmd/megacheck/megacheck.go @@ -0,0 +1,122 @@ +// megacheck runs staticcheck, gosimple and unused. +package main // import "honnef.co/go/tools/cmd/megacheck" + +import ( + "os" + + "honnef.co/go/tools/lint/lintutil" + "honnef.co/go/tools/simple" + "honnef.co/go/tools/staticcheck" + "honnef.co/go/tools/unused" +) + +func main() { + var flags struct { + staticcheck struct { + enabled bool + generated bool + exitNonZero bool + } + gosimple struct { + enabled bool + generated bool + exitNonZero bool + } + unused struct { + enabled bool + constants bool + fields bool + functions bool + types bool + variables bool + debug string + wholeProgram bool + reflection bool + exitNonZero bool + } + } + fs := lintutil.FlagSet("megacheck") + fs.BoolVar(&flags.gosimple.enabled, + "simple.enabled", true, "Run gosimple") + fs.BoolVar(&flags.gosimple.generated, + "simple.generated", false, "Check generated code") + fs.BoolVar(&flags.gosimple.exitNonZero, + "simple.exit-non-zero", false, "Exit non-zero if any problems were found") + + fs.BoolVar(&flags.staticcheck.enabled, + "staticcheck.enabled", true, "Run staticcheck") + fs.BoolVar(&flags.staticcheck.generated, + "staticcheck.generated", false, "Check generated code (only applies to a subset of checks)") + fs.BoolVar(&flags.staticcheck.exitNonZero, + "staticcheck.exit-non-zero", true, "Exit non-zero if any problems were found") + + fs.BoolVar(&flags.unused.enabled, + "unused.enabled", true, "Run unused") + fs.BoolVar(&flags.unused.constants, + "unused.consts", true, "Report unused constants") + fs.BoolVar(&flags.unused.fields, + "unused.fields", true, "Report unused fields") + fs.BoolVar(&flags.unused.functions, + "unused.funcs", true, "Report unused functions and methods") + fs.BoolVar(&flags.unused.types, + "unused.types", true, "Report unused types") + fs.BoolVar(&flags.unused.variables, + "unused.vars", true, "Report unused variables") + fs.BoolVar(&flags.unused.wholeProgram, + "unused.exported", false, "Treat arguments as a program and report unused exported identifiers") + fs.BoolVar(&flags.unused.reflection, + "unused.reflect", true, "Consider identifiers as used when it's likely they'll be accessed via reflection") + fs.BoolVar(&flags.unused.exitNonZero, + "unused.exit-non-zero", true, "Exit non-zero if any problems were found") + + fs.Parse(os.Args[1:]) + + var checkers []lintutil.CheckerConfig + + if flags.staticcheck.enabled { + sac := staticcheck.NewChecker() + sac.CheckGenerated = flags.staticcheck.generated + checkers = append(checkers, lintutil.CheckerConfig{ + Checker: sac, + ExitNonZero: flags.staticcheck.exitNonZero, + }) + } + + if flags.gosimple.enabled { + sc := simple.NewChecker() + sc.CheckGenerated = flags.gosimple.generated + checkers = append(checkers, lintutil.CheckerConfig{ + Checker: sc, + ExitNonZero: flags.gosimple.exitNonZero, + }) + } + + if flags.unused.enabled { + var mode unused.CheckMode + if flags.unused.constants { + mode |= unused.CheckConstants + } + if flags.unused.fields { + mode |= unused.CheckFields + } + if flags.unused.functions { + mode |= unused.CheckFunctions + } + if flags.unused.types { + mode |= unused.CheckTypes + } + if flags.unused.variables { + mode |= unused.CheckVariables + } + uc := unused.NewChecker(mode) + uc.WholeProgram = flags.unused.wholeProgram + uc.ConsiderReflection = flags.unused.reflection + checkers = append(checkers, lintutil.CheckerConfig{ + Checker: unused.NewLintChecker(uc), + ExitNonZero: flags.unused.exitNonZero, + }) + + } + + lintutil.ProcessFlagSet(checkers, fs) +} diff --git a/vendor/honnef.co/go/tools/deprecated/stdlib.go b/vendor/honnef.co/go/tools/deprecated/stdlib.go new file mode 100644 index 0000000..b6b217c --- /dev/null +++ b/vendor/honnef.co/go/tools/deprecated/stdlib.go @@ -0,0 +1,54 @@ +package deprecated + +type Deprecation struct { + DeprecatedSince int + AlternativeAvailableSince int +} + +var Stdlib = map[string]Deprecation{ + "image/jpeg.Reader": {4, 0}, + // FIXME(dh): AllowBinary isn't being detected as deprecated + // because the comment has a newline right after "Deprecated:" + "go/build.AllowBinary": {7, 7}, + "(archive/zip.FileHeader).CompressedSize": {1, 1}, + "(archive/zip.FileHeader).UncompressedSize": {1, 1}, + "(go/doc.Package).Bugs": {1, 1}, + "os.SEEK_SET": {7, 7}, + "os.SEEK_CUR": {7, 7}, + "os.SEEK_END": {7, 7}, + "(net.Dialer).Cancel": {7, 7}, + "runtime.CPUProfile": {9, 0}, + "compress/flate.ReadError": {6, 6}, + "compress/flate.WriteError": {6, 6}, + "path/filepath.HasPrefix": {0, 0}, + "(net/http.Transport).Dial": {7, 7}, + "(*net/http.Transport).CancelRequest": {6, 5}, + "net/http.ErrWriteAfterFlush": {7, 0}, + "net/http.ErrHeaderTooLong": {8, 0}, + "net/http.ErrShortBody": {8, 0}, + "net/http.ErrMissingContentLength": {8, 0}, + "net/http/httputil.ErrPersistEOF": {0, 0}, + "net/http/httputil.ErrClosed": {0, 0}, + "net/http/httputil.ErrPipeline": {0, 0}, + "net/http/httputil.ServerConn": {0, 0}, + "net/http/httputil.NewServerConn": {0, 0}, + "net/http/httputil.ClientConn": {0, 0}, + "net/http/httputil.NewClientConn": {0, 0}, + "net/http/httputil.NewProxyClientConn": {0, 0}, + "(net/http.Request).Cancel": {7, 7}, + "(text/template/parse.PipeNode).Line": {1, 1}, + "(text/template/parse.ActionNode).Line": {1, 1}, + "(text/template/parse.BranchNode).Line": {1, 1}, + "(text/template/parse.TemplateNode).Line": {1, 1}, + "database/sql/driver.ColumnConverter": {9, 9}, + "database/sql/driver.Execer": {8, 8}, + "database/sql/driver.Queryer": {8, 8}, + "(database/sql/driver.Conn).Begin": {8, 8}, + "(database/sql/driver.Stmt).Exec": {8, 8}, + "(database/sql/driver.Stmt).Query": {8, 8}, + "syscall.StringByteSlice": {1, 1}, + "syscall.StringBytePtr": {1, 1}, + "syscall.StringSlicePtr": {1, 1}, + "syscall.StringToUTF16": {1, 1}, + "syscall.StringToUTF16Ptr": {1, 1}, +} diff --git a/vendor/honnef.co/go/tools/functions/concrete.go b/vendor/honnef.co/go/tools/functions/concrete.go new file mode 100644 index 0000000..932acd0 --- /dev/null +++ b/vendor/honnef.co/go/tools/functions/concrete.go @@ -0,0 +1,56 @@ +package functions + +import ( + "go/token" + "go/types" + + "honnef.co/go/tools/ssa" +) + +func concreteReturnTypes(fn *ssa.Function) []*types.Tuple { + res := fn.Signature.Results() + if res == nil { + return nil + } + ifaces := make([]bool, res.Len()) + any := false + for i := 0; i < res.Len(); i++ { + _, ifaces[i] = res.At(i).Type().Underlying().(*types.Interface) + any = any || ifaces[i] + } + if !any { + return []*types.Tuple{res} + } + var out []*types.Tuple + for _, block := range fn.Blocks { + if len(block.Instrs) == 0 { + continue + } + ret, ok := block.Instrs[len(block.Instrs)-1].(*ssa.Return) + if !ok { + continue + } + vars := make([]*types.Var, res.Len()) + for i, v := range ret.Results { + var typ types.Type + if !ifaces[i] { + typ = res.At(i).Type() + } else if mi, ok := v.(*ssa.MakeInterface); ok { + // TODO(dh): if mi.X is a function call that returns + // an interface, call concreteReturnTypes on that + // function (or, really, go through Descriptions, + // avoid infinite recursion etc, just like nil error + // detection) + + // TODO(dh): support Phi nodes + typ = mi.X.Type() + } else { + typ = res.At(i).Type() + } + vars[i] = types.NewParam(token.NoPos, nil, "", typ) + } + out = append(out, types.NewTuple(vars...)) + } + // TODO(dh): deduplicate out + return out +} diff --git a/vendor/honnef.co/go/tools/functions/functions.go b/vendor/honnef.co/go/tools/functions/functions.go new file mode 100644 index 0000000..c5fe2d7 --- /dev/null +++ b/vendor/honnef.co/go/tools/functions/functions.go @@ -0,0 +1,150 @@ +package functions + +import ( + "go/types" + "sync" + + "honnef.co/go/tools/callgraph" + "honnef.co/go/tools/callgraph/static" + "honnef.co/go/tools/ssa" + "honnef.co/go/tools/staticcheck/vrp" +) + +var stdlibDescs = map[string]Description{ + "errors.New": Description{Pure: true}, + + "fmt.Errorf": Description{Pure: true}, + "fmt.Sprintf": Description{Pure: true}, + "fmt.Sprint": Description{Pure: true}, + + "sort.Reverse": Description{Pure: true}, + + "strings.Map": Description{Pure: true}, + "strings.Repeat": Description{Pure: true}, + "strings.Replace": Description{Pure: true}, + "strings.Title": Description{Pure: true}, + "strings.ToLower": Description{Pure: true}, + "strings.ToLowerSpecial": Description{Pure: true}, + "strings.ToTitle": Description{Pure: true}, + "strings.ToTitleSpecial": Description{Pure: true}, + "strings.ToUpper": Description{Pure: true}, + "strings.ToUpperSpecial": Description{Pure: true}, + "strings.Trim": Description{Pure: true}, + "strings.TrimFunc": Description{Pure: true}, + "strings.TrimLeft": Description{Pure: true}, + "strings.TrimLeftFunc": Description{Pure: true}, + "strings.TrimPrefix": Description{Pure: true}, + "strings.TrimRight": Description{Pure: true}, + "strings.TrimRightFunc": Description{Pure: true}, + "strings.TrimSpace": Description{Pure: true}, + "strings.TrimSuffix": Description{Pure: true}, + + "(*net/http.Request).WithContext": Description{Pure: true}, + + "math/rand.Read": Description{NilError: true}, + "(*math/rand.Rand).Read": Description{NilError: true}, +} + +type Description struct { + // The function is known to be pure + Pure bool + // The function is known to be a stub + Stub bool + // The function is known to never return (panics notwithstanding) + Infinite bool + // Variable ranges + Ranges vrp.Ranges + Loops []Loop + // Function returns an error as its last argument, but it is + // always nil + NilError bool + ConcreteReturnTypes []*types.Tuple +} + +type descriptionEntry struct { + ready chan struct{} + result Description +} + +type Descriptions struct { + CallGraph *callgraph.Graph + mu sync.Mutex + cache map[*ssa.Function]*descriptionEntry +} + +func NewDescriptions(prog *ssa.Program) *Descriptions { + return &Descriptions{ + CallGraph: static.CallGraph(prog), + cache: map[*ssa.Function]*descriptionEntry{}, + } +} + +func (d *Descriptions) Get(fn *ssa.Function) Description { + d.mu.Lock() + fd := d.cache[fn] + if fd == nil { + fd = &descriptionEntry{ + ready: make(chan struct{}), + } + d.cache[fn] = fd + d.mu.Unlock() + + { + fd.result = stdlibDescs[fn.RelString(nil)] + fd.result.Pure = fd.result.Pure || d.IsPure(fn) + fd.result.Stub = fd.result.Stub || d.IsStub(fn) + fd.result.Infinite = fd.result.Infinite || !terminates(fn) + fd.result.Ranges = vrp.BuildGraph(fn).Solve() + fd.result.Loops = findLoops(fn) + fd.result.NilError = fd.result.NilError || IsNilError(fn) + fd.result.ConcreteReturnTypes = concreteReturnTypes(fn) + } + + close(fd.ready) + } else { + d.mu.Unlock() + <-fd.ready + } + return fd.result +} + +func IsNilError(fn *ssa.Function) bool { + // TODO(dh): This is very simplistic, as we only look for constant + // nil returns. A more advanced approach would work transitively. + // An even more advanced approach would be context-aware and + // determine nil errors based on inputs (e.g. io.WriteString to a + // bytes.Buffer will always return nil, but an io.WriteString to + // an os.File might not). Similarly, an os.File opened for reading + // won't error on Close, but other files will. + res := fn.Signature.Results() + if res.Len() == 0 { + return false + } + last := res.At(res.Len() - 1) + if types.TypeString(last.Type(), nil) != "error" { + return false + } + + if fn.Blocks == nil { + return false + } + for _, block := range fn.Blocks { + if len(block.Instrs) == 0 { + continue + } + ins := block.Instrs[len(block.Instrs)-1] + ret, ok := ins.(*ssa.Return) + if !ok { + continue + } + v := ret.Results[len(ret.Results)-1] + c, ok := v.(*ssa.Const) + if !ok { + return false + } + if !c.IsNil() { + return false + } + } + return true +} diff --git a/vendor/honnef.co/go/tools/functions/loops.go b/vendor/honnef.co/go/tools/functions/loops.go new file mode 100644 index 0000000..63011cf --- /dev/null +++ b/vendor/honnef.co/go/tools/functions/loops.go @@ -0,0 +1,50 @@ +package functions + +import "honnef.co/go/tools/ssa" + +type Loop map[*ssa.BasicBlock]bool + +func findLoops(fn *ssa.Function) []Loop { + if fn.Blocks == nil { + return nil + } + tree := fn.DomPreorder() + var sets []Loop + for _, h := range tree { + for _, n := range h.Preds { + if !h.Dominates(n) { + continue + } + // n is a back-edge to h + // h is the loop header + if n == h { + sets = append(sets, Loop{n: true}) + continue + } + set := Loop{h: true, n: true} + for _, b := range allPredsBut(n, h, nil) { + set[b] = true + } + sets = append(sets, set) + } + } + return sets +} + +func allPredsBut(b, but *ssa.BasicBlock, list []*ssa.BasicBlock) []*ssa.BasicBlock { +outer: + for _, pred := range b.Preds { + if pred == but { + continue + } + for _, p := range list { + // TODO improve big-o complexity of this function + if pred == p { + continue outer + } + } + list = append(list, pred) + list = allPredsBut(pred, but, list) + } + return list +} diff --git a/vendor/honnef.co/go/tools/functions/pure.go b/vendor/honnef.co/go/tools/functions/pure.go new file mode 100644 index 0000000..d1c4d03 --- /dev/null +++ b/vendor/honnef.co/go/tools/functions/pure.go @@ -0,0 +1,123 @@ +package functions + +import ( + "go/token" + "go/types" + + "honnef.co/go/tools/callgraph" + "honnef.co/go/tools/lint" + "honnef.co/go/tools/ssa" +) + +// IsStub reports whether a function is a stub. A function is +// considered a stub if it has no instructions or exactly one +// instruction, which must be either returning only constant values or +// a panic. +func (d *Descriptions) IsStub(fn *ssa.Function) bool { + if len(fn.Blocks) == 0 { + return true + } + if len(fn.Blocks) > 1 { + return false + } + instrs := lint.FilterDebug(fn.Blocks[0].Instrs) + if len(instrs) != 1 { + return false + } + + switch instrs[0].(type) { + case *ssa.Return: + // Since this is the only instruction, the return value must + // be a constant. We consider all constants as stubs, not just + // the zero value. This does not, unfortunately, cover zero + // initialised structs, as these cause additional + // instructions. + return true + case *ssa.Panic: + return true + default: + return false + } +} + +func (d *Descriptions) IsPure(fn *ssa.Function) bool { + if fn.Signature.Results().Len() == 0 { + // A function with no return values is empty or is doing some + // work we cannot see (for example because of build tags); + // don't consider it pure. + return false + } + + for _, param := range fn.Params { + if _, ok := param.Type().Underlying().(*types.Basic); !ok { + return false + } + } + + if fn.Blocks == nil { + return false + } + checkCall := func(common *ssa.CallCommon) bool { + if common.IsInvoke() { + return false + } + builtin, ok := common.Value.(*ssa.Builtin) + if !ok { + if common.StaticCallee() != fn { + if common.StaticCallee() == nil { + return false + } + // TODO(dh): ideally, IsPure wouldn't be responsible + // for avoiding infinite recursion, but + // FunctionDescriptions would be. + node := d.CallGraph.CreateNode(common.StaticCallee()) + if callgraph.PathSearch(node, func(other *callgraph.Node) bool { + return other.Func == fn + }) != nil { + return false + } + if !d.Get(common.StaticCallee()).Pure { + return false + } + } + } else { + switch builtin.Name() { + case "len", "cap", "make", "new": + default: + return false + } + } + return true + } + for _, b := range fn.Blocks { + for _, ins := range b.Instrs { + switch ins := ins.(type) { + case *ssa.Call: + if !checkCall(ins.Common()) { + return false + } + case *ssa.Defer: + if !checkCall(&ins.Call) { + return false + } + case *ssa.Select: + return false + case *ssa.Send: + return false + case *ssa.Go: + return false + case *ssa.Panic: + return false + case *ssa.Store: + return false + case *ssa.FieldAddr: + return false + case *ssa.UnOp: + if ins.Op == token.MUL || ins.Op == token.AND { + return false + } + } + } + } + return true +} diff --git a/vendor/honnef.co/go/tools/functions/terminates.go b/vendor/honnef.co/go/tools/functions/terminates.go new file mode 100644 index 0000000..65f9e16 --- /dev/null +++ b/vendor/honnef.co/go/tools/functions/terminates.go @@ -0,0 +1,24 @@ +package functions + +import "honnef.co/go/tools/ssa" + +// terminates reports whether fn is supposed to return, that is if it +// has at least one theoretic path that returns from the function. +// Explicit panics do not count as terminating. +func terminates(fn *ssa.Function) bool { + if fn.Blocks == nil { + // assuming that a function terminates is the conservative + // choice + return true + } + + for _, block := range fn.Blocks { + if len(block.Instrs) == 0 { + continue + } + if _, ok := block.Instrs[len(block.Instrs)-1].(*ssa.Return); ok { + return true + } + } + return false +} diff --git a/vendor/honnef.co/go/tools/gcsizes/LICENSE b/vendor/honnef.co/go/tools/gcsizes/LICENSE new file mode 100644 index 0000000..6a66aea --- /dev/null +++ b/vendor/honnef.co/go/tools/gcsizes/LICENSE @@ -0,0 +1,27 @@ +Copyright (c) 2009 The Go Authors. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are +met: + + * Redistributions of source code must retain the above copyright +notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above +copyright notice, this list of conditions and the following disclaimer +in the documentation and/or other materials provided with the +distribution. + * Neither the name of Google Inc. nor the names of its +contributors may be used to endorse or promote products derived from +this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/vendor/honnef.co/go/tools/internal/sharedcheck/lint.go b/vendor/honnef.co/go/tools/internal/sharedcheck/lint.go new file mode 100644 index 0000000..5f62fc2 --- /dev/null +++ b/vendor/honnef.co/go/tools/internal/sharedcheck/lint.go @@ -0,0 +1,70 @@ +package sharedcheck + +import ( + "go/ast" + "go/types" + + "honnef.co/go/tools/lint" + "honnef.co/go/tools/ssa" +) + +func CheckRangeStringRunes(nodeFns map[ast.Node]*ssa.Function, j *lint.Job) { + fn := func(node ast.Node) bool { + rng, ok := node.(*ast.RangeStmt) + if !ok || !lint.IsBlank(rng.Key) { + return true + } + ssafn := nodeFns[rng] + if ssafn == nil { + return true + } + v, _ := ssafn.ValueForExpr(rng.X) + + // Check that we're converting from string to []rune + val, _ := v.(*ssa.Convert) + if val == nil { + return true + } + Tsrc, ok := val.X.Type().(*types.Basic) + if !ok || Tsrc.Kind() != types.String { + return true + } + Tdst, ok := val.Type().(*types.Slice) + if !ok { + return true + } + TdstElem, ok := Tdst.Elem().(*types.Basic) + if !ok || TdstElem.Kind() != types.Int32 { + return true + } + + // Check that the result of the conversion is only used to + // range over + refs := val.Referrers() + if refs == nil { + return true + } + + // Expect two refs: one for obtaining the length of the slice, + // one for accessing the elements + if len(lint.FilterDebug(*refs)) != 2 { + // TODO(dh): right now, we check that only one place + // refers to our slice. This will miss cases such as + // ranging over the slice twice. Ideally, we'd ensure that + // the slice is only used for ranging over (without + // accessing the key), but that is harder to do because in + // SSA form, ranging over a slice looks like an ordinary + // loop with index increments and slice accesses. We'd + // have to look at the associated AST node to check that + // it's a range statement. + return true + } + + j.Errorf(rng, "should range over string, not []rune(string)") + + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} diff --git a/vendor/honnef.co/go/tools/lint/LICENSE b/vendor/honnef.co/go/tools/lint/LICENSE new file mode 100644 index 0000000..796130a --- /dev/null +++ b/vendor/honnef.co/go/tools/lint/LICENSE @@ -0,0 +1,28 @@ +Copyright (c) 2013 The Go Authors. All rights reserved. +Copyright (c) 2016 Dominik Honnef. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are +met: + + * Redistributions of source code must retain the above copyright +notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above +copyright notice, this list of conditions and the following disclaimer +in the documentation and/or other materials provided with the +distribution. + * Neither the name of Google Inc. nor the names of its +contributors may be used to endorse or promote products derived from +this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/vendor/honnef.co/go/tools/lint/lint.go b/vendor/honnef.co/go/tools/lint/lint.go new file mode 100644 index 0000000..75a5198 --- /dev/null +++ b/vendor/honnef.co/go/tools/lint/lint.go @@ -0,0 +1,844 @@ +// Copyright (c) 2013 The Go Authors. All rights reserved. +// +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file or at +// https://developers.google.com/open-source/licenses/bsd. + +// Package lint provides the foundation for tools like gosimple. +package lint // import "honnef.co/go/tools/lint" + +import ( + "bytes" + "fmt" + "go/ast" + "go/build" + "go/constant" + "go/printer" + "go/token" + "go/types" + "path/filepath" + "runtime" + "sort" + "strings" + "sync" + "unicode" + + "golang.org/x/tools/go/ast/astutil" + "golang.org/x/tools/go/loader" + "honnef.co/go/tools/ssa" + "honnef.co/go/tools/ssa/ssautil" +) + +type Job struct { + Program *Program + + checker string + check string + problems []Problem +} + +type Ignore interface { + Match(p Problem) bool +} + +type LineIgnore struct { + File string + Line int + Checks []string + matched bool + pos token.Pos +} + +func (li *LineIgnore) Match(p Problem) bool { + if p.Position.Filename != li.File || p.Position.Line != li.Line { + return false + } + for _, c := range li.Checks { + if m, _ := filepath.Match(c, p.Check); m { + li.matched = true + return true + } + } + return false +} + +func (li *LineIgnore) String() string { + matched := "not matched" + if li.matched { + matched = "matched" + } + return fmt.Sprintf("%s:%d %s (%s)", li.File, li.Line, strings.Join(li.Checks, ", "), matched) +} + +type FileIgnore struct { + File string + Checks []string +} + +func (fi *FileIgnore) Match(p Problem) bool { + if p.Position.Filename != fi.File { + return false + } + for _, c := range fi.Checks { + if m, _ := filepath.Match(c, p.Check); m { + return true + } + } + return false +} + +type GlobIgnore struct { + Pattern string + Checks []string +} + +func (gi *GlobIgnore) Match(p Problem) bool { + if gi.Pattern != "*" { + pkgpath := p.Package.Path() + if strings.HasSuffix(pkgpath, "_test") { + pkgpath = pkgpath[:len(pkgpath)-len("_test")] + } + name := filepath.Join(pkgpath, filepath.Base(p.Position.Filename)) + if m, _ := filepath.Match(gi.Pattern, name); !m { + return false + } + } + for _, c := range gi.Checks { + if m, _ := filepath.Match(c, p.Check); m { + return true + } + } + return false +} + +type Program struct { + SSA *ssa.Program + Prog *loader.Program + // TODO(dh): Rename to InitialPackages? + Packages []*Pkg + InitialFunctions []*ssa.Function + AllFunctions []*ssa.Function + Files []*ast.File + Info *types.Info + GoVersion int + + tokenFileMap map[*token.File]*ast.File + astFileMap map[*ast.File]*Pkg +} + +type Func func(*Job) + +// Problem represents a problem in some source code. +type Problem struct { + pos token.Pos + Position token.Position // position in source file + Text string // the prose that describes the problem + Check string + Checker string + Package *types.Package + Ignored bool +} + +func (p *Problem) String() string { + if p.Check == "" { + return p.Text + } + return fmt.Sprintf("%s (%s)", p.Text, p.Check) +} + +type Checker interface { + Name() string + Prefix() string + Init(*Program) + Funcs() map[string]Func +} + +// A Linter lints Go source code. +type Linter struct { + Checker Checker + Ignores []Ignore + GoVersion int + ReturnIgnored bool + + automaticIgnores []Ignore +} + +func (l *Linter) ignore(p Problem) bool { + ignored := false + for _, ig := range l.automaticIgnores { + // We cannot short-circuit these, as we want to record, for + // each ignore, whether it matched or not. + if ig.Match(p) { + ignored = true + } + } + if ignored { + // no need to execute other ignores if we've already had a + // match. + return true + } + for _, ig := range l.Ignores { + // We can short-circuit here, as we aren't tracking any + // information. + if ig.Match(p) { + return true + } + } + + return false +} + +func (prog *Program) File(node Positioner) *ast.File { + return prog.tokenFileMap[prog.SSA.Fset.File(node.Pos())] +} + +func (j *Job) File(node Positioner) *ast.File { + return j.Program.File(node) +} + +// TODO(dh): switch to sort.Slice when Go 1.9 lands. +type byPosition struct { + fset *token.FileSet + ps []Problem +} + +func (ps byPosition) Len() int { + return len(ps.ps) +} + +func (ps byPosition) Less(i int, j int) bool { + pi, pj := ps.ps[i].Position, ps.ps[j].Position + + if pi.Filename != pj.Filename { + return pi.Filename < pj.Filename + } + if pi.Line != pj.Line { + return pi.Line < pj.Line + } + if pi.Column != pj.Column { + return pi.Column < pj.Column + } + + return ps.ps[i].Text < ps.ps[j].Text +} + +func (ps byPosition) Swap(i int, j int) { + ps.ps[i], ps.ps[j] = ps.ps[j], ps.ps[i] +} + +func parseDirective(s string) (cmd string, args []string) { + if !strings.HasPrefix(s, "//lint:") { + return "", nil + } + s = strings.TrimPrefix(s, "//lint:") + fields := strings.Split(s, " ") + return fields[0], fields[1:] +} + +func (l *Linter) Lint(lprog *loader.Program, conf *loader.Config) []Problem { + ssaprog := ssautil.CreateProgram(lprog, ssa.GlobalDebug) + ssaprog.Build() + pkgMap := map[*ssa.Package]*Pkg{} + var pkgs []*Pkg + for _, pkginfo := range lprog.InitialPackages() { + ssapkg := ssaprog.Package(pkginfo.Pkg) + var bp *build.Package + if len(pkginfo.Files) != 0 { + path := lprog.Fset.Position(pkginfo.Files[0].Pos()).Filename + dir := filepath.Dir(path) + var err error + ctx := conf.Build + if ctx == nil { + ctx = &build.Default + } + bp, err = ctx.ImportDir(dir, 0) + if err != nil { + // shouldn't happen + } + } + pkg := &Pkg{ + Package: ssapkg, + Info: pkginfo, + BuildPkg: bp, + } + pkgMap[ssapkg] = pkg + pkgs = append(pkgs, pkg) + } + prog := &Program{ + SSA: ssaprog, + Prog: lprog, + Packages: pkgs, + Info: &types.Info{}, + GoVersion: l.GoVersion, + tokenFileMap: map[*token.File]*ast.File{}, + astFileMap: map[*ast.File]*Pkg{}, + } + + initial := map[*types.Package]struct{}{} + for _, pkg := range pkgs { + initial[pkg.Info.Pkg] = struct{}{} + } + for fn := range ssautil.AllFunctions(ssaprog) { + if fn.Pkg == nil { + continue + } + prog.AllFunctions = append(prog.AllFunctions, fn) + if _, ok := initial[fn.Pkg.Pkg]; ok { + prog.InitialFunctions = append(prog.InitialFunctions, fn) + } + } + for _, pkg := range pkgs { + prog.Files = append(prog.Files, pkg.Info.Files...) + + ssapkg := ssaprog.Package(pkg.Info.Pkg) + for _, f := range pkg.Info.Files { + prog.astFileMap[f] = pkgMap[ssapkg] + } + } + + for _, pkginfo := range lprog.AllPackages { + for _, f := range pkginfo.Files { + tf := lprog.Fset.File(f.Pos()) + prog.tokenFileMap[tf] = f + } + } + + var out []Problem + l.automaticIgnores = nil + for _, pkginfo := range lprog.InitialPackages() { + for _, f := range pkginfo.Files { + cm := ast.NewCommentMap(lprog.Fset, f, f.Comments) + for node, cgs := range cm { + for _, cg := range cgs { + for _, c := range cg.List { + if !strings.HasPrefix(c.Text, "//lint:") { + continue + } + cmd, args := parseDirective(c.Text) + switch cmd { + case "ignore", "file-ignore": + if len(args) < 2 { + // FIXME(dh): this causes duplicated warnings when using megacheck + p := Problem{ + pos: c.Pos(), + Position: prog.DisplayPosition(c.Pos()), + Text: "malformed linter directive; missing the required reason field?", + Check: "", + Checker: l.Checker.Name(), + Package: nil, + } + out = append(out, p) + continue + } + default: + // unknown directive, ignore + continue + } + checks := strings.Split(args[0], ",") + pos := prog.DisplayPosition(node.Pos()) + var ig Ignore + switch cmd { + case "ignore": + ig = &LineIgnore{ + File: pos.Filename, + Line: pos.Line, + Checks: checks, + pos: c.Pos(), + } + case "file-ignore": + ig = &FileIgnore{ + File: pos.Filename, + Checks: checks, + } + } + l.automaticIgnores = append(l.automaticIgnores, ig) + } + } + } + } + } + + sizes := struct { + types int + defs int + uses int + implicits int + selections int + scopes int + }{} + for _, pkg := range pkgs { + sizes.types += len(pkg.Info.Info.Types) + sizes.defs += len(pkg.Info.Info.Defs) + sizes.uses += len(pkg.Info.Info.Uses) + sizes.implicits += len(pkg.Info.Info.Implicits) + sizes.selections += len(pkg.Info.Info.Selections) + sizes.scopes += len(pkg.Info.Info.Scopes) + } + prog.Info.Types = make(map[ast.Expr]types.TypeAndValue, sizes.types) + prog.Info.Defs = make(map[*ast.Ident]types.Object, sizes.defs) + prog.Info.Uses = make(map[*ast.Ident]types.Object, sizes.uses) + prog.Info.Implicits = make(map[ast.Node]types.Object, sizes.implicits) + prog.Info.Selections = make(map[*ast.SelectorExpr]*types.Selection, sizes.selections) + prog.Info.Scopes = make(map[ast.Node]*types.Scope, sizes.scopes) + for _, pkg := range pkgs { + for k, v := range pkg.Info.Info.Types { + prog.Info.Types[k] = v + } + for k, v := range pkg.Info.Info.Defs { + prog.Info.Defs[k] = v + } + for k, v := range pkg.Info.Info.Uses { + prog.Info.Uses[k] = v + } + for k, v := range pkg.Info.Info.Implicits { + prog.Info.Implicits[k] = v + } + for k, v := range pkg.Info.Info.Selections { + prog.Info.Selections[k] = v + } + for k, v := range pkg.Info.Info.Scopes { + prog.Info.Scopes[k] = v + } + } + l.Checker.Init(prog) + + funcs := l.Checker.Funcs() + var keys []string + for k := range funcs { + keys = append(keys, k) + } + sort.Strings(keys) + + var jobs []*Job + for _, k := range keys { + j := &Job{ + Program: prog, + checker: l.Checker.Name(), + check: k, + } + jobs = append(jobs, j) + } + wg := &sync.WaitGroup{} + for _, j := range jobs { + wg.Add(1) + go func(j *Job) { + defer wg.Done() + fn := funcs[j.check] + if fn == nil { + return + } + fn(j) + }(j) + } + wg.Wait() + + for _, j := range jobs { + for _, p := range j.problems { + p.Ignored = l.ignore(p) + if l.ReturnIgnored || !p.Ignored { + out = append(out, p) + } + } + } + + for _, ig := range l.automaticIgnores { + ig, ok := ig.(*LineIgnore) + if !ok { + continue + } + if ig.matched { + continue + } + for _, c := range ig.Checks { + idx := strings.IndexFunc(c, func(r rune) bool { + return unicode.IsNumber(r) + }) + if idx == -1 { + // malformed check name, backing out + continue + } + if c[:idx] != l.Checker.Prefix() { + // not for this checker + continue + } + p := Problem{ + pos: ig.pos, + Position: prog.DisplayPosition(ig.pos), + Text: "this linter directive didn't match anything; should it be removed?", + Check: "", + Checker: l.Checker.Name(), + Package: nil, + } + out = append(out, p) + } + } + + sort.Sort(byPosition{lprog.Fset, out}) + return out +} + +// Pkg represents a package being linted. +type Pkg struct { + *ssa.Package + Info *loader.PackageInfo + BuildPkg *build.Package +} + +type packager interface { + Package() *ssa.Package +} + +func IsExample(fn *ssa.Function) bool { + if !strings.HasPrefix(fn.Name(), "Example") { + return false + } + f := fn.Prog.Fset.File(fn.Pos()) + if f == nil { + return false + } + return strings.HasSuffix(f.Name(), "_test.go") +} + +func (j *Job) IsInTest(node Positioner) bool { + f := j.Program.SSA.Fset.File(node.Pos()) + return f != nil && strings.HasSuffix(f.Name(), "_test.go") +} + +func (j *Job) IsInMain(node Positioner) bool { + if node, ok := node.(packager); ok { + return node.Package().Pkg.Name() == "main" + } + pkg := j.NodePackage(node) + if pkg == nil { + return false + } + return pkg.Pkg.Name() == "main" +} + +type Positioner interface { + Pos() token.Pos +} + +func (prog *Program) DisplayPosition(p token.Pos) token.Position { + // The //line compiler directive can be used to change the file + // name and line numbers associated with code. This can, for + // example, be used by code generation tools. The most prominent + // example is 'go tool cgo', which uses //line directives to refer + // back to the original source code. + // + // In the context of our linters, we need to treat these + // directives differently depending on context. For cgo files, we + // want to honour the directives, so that line numbers are + // adjusted correctly. For all other files, we want to ignore the + // directives, so that problems are reported at their actual + // position and not, for example, a yacc grammar file. This also + // affects the ignore mechanism, since it operates on the position + // information stored within problems. With this implementation, a + // user will ignore foo.go, not foo.y + + pkg := prog.astFileMap[prog.tokenFileMap[prog.Prog.Fset.File(p)]] + bp := pkg.BuildPkg + adjPos := prog.Prog.Fset.Position(p) + if bp == nil { + // couldn't find the package for some reason (deleted? faulty + // file system?) + return adjPos + } + base := filepath.Base(adjPos.Filename) + for _, f := range bp.CgoFiles { + if f == base { + // this is a cgo file, use the adjusted position + return adjPos + } + } + // not a cgo file, ignore //line directives + return prog.Prog.Fset.PositionFor(p, false) +} + +func (j *Job) Errorf(n Positioner, format string, args ...interface{}) *Problem { + tf := j.Program.SSA.Fset.File(n.Pos()) + f := j.Program.tokenFileMap[tf] + pkg := j.Program.astFileMap[f].Pkg + + pos := j.Program.DisplayPosition(n.Pos()) + problem := Problem{ + pos: n.Pos(), + Position: pos, + Text: fmt.Sprintf(format, args...), + Check: j.check, + Checker: j.checker, + Package: pkg, + } + j.problems = append(j.problems, problem) + return &j.problems[len(j.problems)-1] +} + +func (j *Job) Render(x interface{}) string { + fset := j.Program.SSA.Fset + var buf bytes.Buffer + if err := printer.Fprint(&buf, fset, x); err != nil { + panic(err) + } + return buf.String() +} + +func (j *Job) RenderArgs(args []ast.Expr) string { + var ss []string + for _, arg := range args { + ss = append(ss, j.Render(arg)) + } + return strings.Join(ss, ", ") +} + +func IsIdent(expr ast.Expr, ident string) bool { + id, ok := expr.(*ast.Ident) + return ok && id.Name == ident +} + +// isBlank returns whether id is the blank identifier "_". +// If id == nil, the answer is false. +func IsBlank(id ast.Expr) bool { + ident, ok := id.(*ast.Ident) + return ok && ident.Name == "_" +} + +func IsZero(expr ast.Expr) bool { + lit, ok := expr.(*ast.BasicLit) + return ok && lit.Kind == token.INT && lit.Value == "0" +} + +func (j *Job) IsNil(expr ast.Expr) bool { + return j.Program.Info.Types[expr].IsNil() +} + +func (j *Job) BoolConst(expr ast.Expr) bool { + val := j.Program.Info.ObjectOf(expr.(*ast.Ident)).(*types.Const).Val() + return constant.BoolVal(val) +} + +func (j *Job) IsBoolConst(expr ast.Expr) bool { + // We explicitly don't support typed bools because more often than + // not, custom bool types are used as binary enums and the + // explicit comparison is desired. + + ident, ok := expr.(*ast.Ident) + if !ok { + return false + } + obj := j.Program.Info.ObjectOf(ident) + c, ok := obj.(*types.Const) + if !ok { + return false + } + basic, ok := c.Type().(*types.Basic) + if !ok { + return false + } + if basic.Kind() != types.UntypedBool && basic.Kind() != types.Bool { + return false + } + return true +} + +func (j *Job) ExprToInt(expr ast.Expr) (int64, bool) { + tv := j.Program.Info.Types[expr] + if tv.Value == nil { + return 0, false + } + if tv.Value.Kind() != constant.Int { + return 0, false + } + return constant.Int64Val(tv.Value) +} + +func (j *Job) ExprToString(expr ast.Expr) (string, bool) { + val := j.Program.Info.Types[expr].Value + if val == nil { + return "", false + } + if val.Kind() != constant.String { + return "", false + } + return constant.StringVal(val), true +} + +func (j *Job) NodePackage(node Positioner) *Pkg { + f := j.File(node) + return j.Program.astFileMap[f] +} + +func IsGenerated(f *ast.File) bool { + comments := f.Comments + if len(comments) > 0 { + comment := comments[0].Text() + return strings.Contains(comment, "Code generated by") || + strings.Contains(comment, "DO NOT EDIT") + } + return false +} + +func Preamble(f *ast.File) string { + cutoff := f.Package + if f.Doc != nil { + cutoff = f.Doc.Pos() + } + var out []string + for _, cmt := range f.Comments { + if cmt.Pos() >= cutoff { + break + } + out = append(out, cmt.Text()) + } + return strings.Join(out, "\n") +} + +func IsPointerLike(T types.Type) bool { + switch T := T.Underlying().(type) { + case *types.Interface, *types.Chan, *types.Map, *types.Pointer: + return true + case *types.Basic: + return T.Kind() == types.UnsafePointer + } + return false +} + +func (j *Job) IsGoVersion(minor int) bool { + return j.Program.GoVersion >= minor +} + +func (j *Job) IsCallToAST(node ast.Node, name string) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return false + } + sel, ok := call.Fun.(*ast.SelectorExpr) + if !ok { + return false + } + fn, ok := j.Program.Info.ObjectOf(sel.Sel).(*types.Func) + return ok && fn.FullName() == name +} + +func (j *Job) IsCallToAnyAST(node ast.Node, names ...string) bool { + for _, name := range names { + if j.IsCallToAST(node, name) { + return true + } + } + return false +} + +func CallName(call *ssa.CallCommon) string { + if call.IsInvoke() { + return "" + } + switch v := call.Value.(type) { + case *ssa.Function: + fn, ok := v.Object().(*types.Func) + if !ok { + return "" + } + return fn.FullName() + case *ssa.Builtin: + return v.Name() + } + return "" +} + +func IsCallTo(call *ssa.CallCommon, name string) bool { + return CallName(call) == name +} + +func FilterDebug(instr []ssa.Instruction) []ssa.Instruction { + var out []ssa.Instruction + for _, ins := range instr { + if _, ok := ins.(*ssa.DebugRef); !ok { + out = append(out, ins) + } + } + return out +} + +func NodeFns(pkgs []*Pkg) map[ast.Node]*ssa.Function { + out := map[ast.Node]*ssa.Function{} + + wg := &sync.WaitGroup{} + chNodeFns := make(chan map[ast.Node]*ssa.Function, runtime.NumCPU()*2) + for _, pkg := range pkgs { + pkg := pkg + wg.Add(1) + go func() { + m := map[ast.Node]*ssa.Function{} + for _, f := range pkg.Info.Files { + ast.Walk(&globalVisitor{m, pkg, f}, f) + } + chNodeFns <- m + wg.Done() + }() + } + go func() { + wg.Wait() + close(chNodeFns) + }() + + for nodeFns := range chNodeFns { + for k, v := range nodeFns { + out[k] = v + } + } + + return out +} + +type globalVisitor struct { + m map[ast.Node]*ssa.Function + pkg *Pkg + f *ast.File +} + +func (v *globalVisitor) Visit(node ast.Node) ast.Visitor { + switch node := node.(type) { + case *ast.CallExpr: + v.m[node] = v.pkg.Func("init") + return v + case *ast.FuncDecl, *ast.FuncLit: + nv := &fnVisitor{v.m, v.f, v.pkg, nil} + return nv.Visit(node) + default: + return v + } +} + +type fnVisitor struct { + m map[ast.Node]*ssa.Function + f *ast.File + pkg *Pkg + ssafn *ssa.Function +} + +func (v *fnVisitor) Visit(node ast.Node) ast.Visitor { + switch node := node.(type) { + case *ast.FuncDecl: + var ssafn *ssa.Function + ssafn = v.pkg.Prog.FuncValue(v.pkg.Info.ObjectOf(node.Name).(*types.Func)) + v.m[node] = ssafn + if ssafn == nil { + return nil + } + return &fnVisitor{v.m, v.f, v.pkg, ssafn} + case *ast.FuncLit: + var ssafn *ssa.Function + path, _ := astutil.PathEnclosingInterval(v.f, node.Pos(), node.Pos()) + ssafn = ssa.EnclosingFunction(v.pkg.Package, path) + v.m[node] = ssafn + if ssafn == nil { + return nil + } + return &fnVisitor{v.m, v.f, v.pkg, ssafn} + case nil: + return nil + default: + v.m[node] = v.ssafn + return v + } +} diff --git a/vendor/honnef.co/go/tools/lint/lintutil/util.go b/vendor/honnef.co/go/tools/lint/lintutil/util.go new file mode 100644 index 0000000..0bb1426 --- /dev/null +++ b/vendor/honnef.co/go/tools/lint/lintutil/util.go @@ -0,0 +1,349 @@ +// Copyright (c) 2013 The Go Authors. All rights reserved. +// +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file or at +// https://developers.google.com/open-source/licenses/bsd. + +// Package lintutil provides helpers for writing linter command lines. +package lintutil // import "honnef.co/go/tools/lint/lintutil" + +import ( + "encoding/json" + "errors" + "flag" + "fmt" + "go/build" + "go/parser" + "go/token" + "go/types" + "io" + "os" + "path/filepath" + "strconv" + "strings" + + "honnef.co/go/tools/lint" + "honnef.co/go/tools/version" + + "github.com/kisielk/gotool" + "golang.org/x/tools/go/loader" +) + +type OutputFormatter interface { + Format(p lint.Problem) +} + +type TextOutput struct { + w io.Writer +} + +func (o TextOutput) Format(p lint.Problem) { + fmt.Fprintf(o.w, "%v: %s\n", relativePositionString(p.Position), p.String()) +} + +type JSONOutput struct { + w io.Writer +} + +func (o JSONOutput) Format(p lint.Problem) { + type location struct { + File string `json:"file"` + Line int `json:"line"` + Column int `json:"column"` + } + jp := struct { + Checker string `json:"checker"` + Code string `json:"code"` + Severity string `json:"severity,omitempty"` + Location location `json:"location"` + Message string `json:"message"` + Ignored bool `json:"ignored"` + }{ + p.Checker, + p.Check, + "", // TODO(dh): support severity + location{ + p.Position.Filename, + p.Position.Line, + p.Position.Column, + }, + p.Text, + p.Ignored, + } + _ = json.NewEncoder(o.w).Encode(jp) +} +func usage(name string, flags *flag.FlagSet) func() { + return func() { + fmt.Fprintf(os.Stderr, "Usage of %s:\n", name) + fmt.Fprintf(os.Stderr, "\t%s [flags] # runs on package in current directory\n", name) + fmt.Fprintf(os.Stderr, "\t%s [flags] packages\n", name) + fmt.Fprintf(os.Stderr, "\t%s [flags] directory\n", name) + fmt.Fprintf(os.Stderr, "\t%s [flags] files... # must be a single package\n", name) + fmt.Fprintf(os.Stderr, "Flags:\n") + flags.PrintDefaults() + } +} + +type runner struct { + checker lint.Checker + tags []string + ignores []lint.Ignore + version int + returnIgnored bool +} + +func resolveRelative(importPaths []string, tags []string) (goFiles bool, err error) { + if len(importPaths) == 0 { + return false, nil + } + if strings.HasSuffix(importPaths[0], ".go") { + // User is specifying a package in terms of .go files, don't resolve + return true, nil + } + wd, err := os.Getwd() + if err != nil { + return false, err + } + ctx := build.Default + ctx.BuildTags = tags + for i, path := range importPaths { + bpkg, err := ctx.Import(path, wd, build.FindOnly) + if err != nil { + return false, fmt.Errorf("can't load package %q: %v", path, err) + } + importPaths[i] = bpkg.ImportPath + } + return false, nil +} + +func parseIgnore(s string) ([]lint.Ignore, error) { + var out []lint.Ignore + if len(s) == 0 { + return nil, nil + } + for _, part := range strings.Fields(s) { + p := strings.Split(part, ":") + if len(p) != 2 { + return nil, errors.New("malformed ignore string") + } + path := p[0] + checks := strings.Split(p[1], ",") + out = append(out, &lint.GlobIgnore{Pattern: path, Checks: checks}) + } + return out, nil +} + +type versionFlag int + +func (v *versionFlag) String() string { + return fmt.Sprintf("1.%d", *v) +} + +func (v *versionFlag) Set(s string) error { + if len(s) < 3 { + return errors.New("invalid Go version") + } + if s[0] != '1' { + return errors.New("invalid Go version") + } + if s[1] != '.' { + return errors.New("invalid Go version") + } + i, err := strconv.Atoi(s[2:]) + *v = versionFlag(i) + return err +} + +func (v *versionFlag) Get() interface{} { + return int(*v) +} + +func FlagSet(name string) *flag.FlagSet { + flags := flag.NewFlagSet("", flag.ExitOnError) + flags.Usage = usage(name, flags) + flags.Float64("min_confidence", 0, "Deprecated; use -ignore instead") + flags.String("tags", "", "List of `build tags`") + flags.String("ignore", "", "Space separated list of checks to ignore, in the following format: 'import/path/file.go:Check1,Check2,...' Both the import path and file name sections support globbing, e.g. 'os/exec/*_test.go'") + flags.Bool("tests", true, "Include tests") + flags.Bool("version", false, "Print version and exit") + flags.Bool("show-ignored", false, "Don't filter ignored problems") + flags.String("f", "text", "Output `format` (valid choices are 'text' and 'json')") + + tags := build.Default.ReleaseTags + v := tags[len(tags)-1][2:] + version := new(versionFlag) + if err := version.Set(v); err != nil { + panic(fmt.Sprintf("internal error: %s", err)) + } + + flags.Var(version, "go", "Target Go `version` in the format '1.x'") + return flags +} + +type CheckerConfig struct { + Checker lint.Checker + ExitNonZero bool +} + +func ProcessFlagSet(confs []CheckerConfig, fs *flag.FlagSet) { + tags := fs.Lookup("tags").Value.(flag.Getter).Get().(string) + ignore := fs.Lookup("ignore").Value.(flag.Getter).Get().(string) + tests := fs.Lookup("tests").Value.(flag.Getter).Get().(bool) + goVersion := fs.Lookup("go").Value.(flag.Getter).Get().(int) + format := fs.Lookup("f").Value.(flag.Getter).Get().(string) + printVersion := fs.Lookup("version").Value.(flag.Getter).Get().(bool) + showIgnored := fs.Lookup("show-ignored").Value.(flag.Getter).Get().(bool) + + if printVersion { + version.Print() + os.Exit(0) + } + + var cs []lint.Checker + for _, conf := range confs { + cs = append(cs, conf.Checker) + } + pss, err := Lint(cs, fs.Args(), &Options{ + Tags: strings.Fields(tags), + LintTests: tests, + Ignores: ignore, + GoVersion: goVersion, + ReturnIgnored: showIgnored, + }) + if err != nil { + fmt.Fprintln(os.Stderr, err) + os.Exit(1) + } + + var ps []lint.Problem + for _, p := range pss { + ps = append(ps, p...) + } + + var f OutputFormatter + switch format { + case "text": + f = TextOutput{os.Stdout} + case "json": + f = JSONOutput{os.Stdout} + default: + fmt.Fprintf(os.Stderr, "unsupported output format %q\n", format) + os.Exit(2) + } + + for _, p := range ps { + f.Format(p) + } + for i, p := range pss { + if len(p) != 0 && confs[i].ExitNonZero { + os.Exit(1) + } + } +} + +type Options struct { + Tags []string + LintTests bool + Ignores string + GoVersion int + ReturnIgnored bool +} + +func Lint(cs []lint.Checker, pkgs []string, opt *Options) ([][]lint.Problem, error) { + if opt == nil { + opt = &Options{} + } + ignores, err := parseIgnore(opt.Ignores) + if err != nil { + return nil, err + } + paths := gotool.ImportPaths(pkgs) + goFiles, err := resolveRelative(paths, opt.Tags) + if err != nil { + return nil, err + } + ctx := build.Default + ctx.BuildTags = opt.Tags + hadError := false + conf := &loader.Config{ + Build: &ctx, + ParserMode: parser.ParseComments, + ImportPkgs: map[string]bool{}, + TypeChecker: types.Config{ + Error: func(err error) { + // Only print the first error found + if hadError { + return + } + hadError = true + fmt.Fprintln(os.Stderr, err) + }, + }, + } + if goFiles { + conf.CreateFromFilenames("adhoc", paths...) + } else { + for _, path := range paths { + conf.ImportPkgs[path] = opt.LintTests + } + } + lprog, err := conf.Load() + if err != nil { + return nil, err + } + + var problems [][]lint.Problem + for _, c := range cs { + runner := &runner{ + checker: c, + tags: opt.Tags, + ignores: ignores, + version: opt.GoVersion, + returnIgnored: opt.ReturnIgnored, + } + problems = append(problems, runner.lint(lprog, conf)) + } + return problems, nil +} + +func shortPath(path string) string { + cwd, err := os.Getwd() + if err != nil { + return path + } + if rel, err := filepath.Rel(cwd, path); err == nil && len(rel) < len(path) { + return rel + } + return path +} + +func relativePositionString(pos token.Position) string { + s := shortPath(pos.Filename) + if pos.IsValid() { + if s != "" { + s += ":" + } + s += fmt.Sprintf("%d:%d", pos.Line, pos.Column) + } + if s == "" { + s = "-" + } + return s +} + +func ProcessArgs(name string, cs []CheckerConfig, args []string) { + flags := FlagSet(name) + flags.Parse(args) + + ProcessFlagSet(cs, flags) +} + +func (runner *runner) lint(lprog *loader.Program, conf *loader.Config) []lint.Problem { + l := &lint.Linter{ + Checker: runner.checker, + Ignores: runner.ignores, + GoVersion: runner.version, + ReturnIgnored: runner.returnIgnored, + } + return l.Lint(lprog, conf) +} diff --git a/vendor/honnef.co/go/tools/simple/lint.go b/vendor/honnef.co/go/tools/simple/lint.go new file mode 100644 index 0000000..47ee690 --- /dev/null +++ b/vendor/honnef.co/go/tools/simple/lint.go @@ -0,0 +1,1771 @@ +// Package simple contains a linter for Go source code. +package simple // import "honnef.co/go/tools/simple" + +import ( + "go/ast" + "go/constant" + "go/token" + "go/types" + "reflect" + "strings" + + "honnef.co/go/tools/internal/sharedcheck" + "honnef.co/go/tools/lint" + "honnef.co/go/tools/ssa" + + "golang.org/x/tools/go/types/typeutil" +) + +type Checker struct { + CheckGenerated bool + MS *typeutil.MethodSetCache + + nodeFns map[ast.Node]*ssa.Function +} + +func NewChecker() *Checker { + return &Checker{ + MS: &typeutil.MethodSetCache{}, + } +} + +func (*Checker) Name() string { return "gosimple" } +func (*Checker) Prefix() string { return "S" } + +func (c *Checker) Init(prog *lint.Program) { + c.nodeFns = lint.NodeFns(prog.Packages) +} + +func (c *Checker) Funcs() map[string]lint.Func { + return map[string]lint.Func{ + "S1000": c.LintSingleCaseSelect, + "S1001": c.LintLoopCopy, + "S1002": c.LintIfBoolCmp, + "S1003": c.LintStringsContains, + "S1004": c.LintBytesCompare, + "S1005": c.LintUnnecessaryBlank, + "S1006": c.LintForTrue, + "S1007": c.LintRegexpRaw, + "S1008": c.LintIfReturn, + "S1009": c.LintRedundantNilCheckWithLen, + "S1010": c.LintSlicing, + "S1011": c.LintLoopAppend, + "S1012": c.LintTimeSince, + "S1013": c.LintSimplerReturn, + "S1014": nil, + "S1015": nil, + "S1016": c.LintSimplerStructConversion, + "S1017": c.LintTrim, + "S1018": c.LintLoopSlide, + "S1019": c.LintMakeLenCap, + "S1020": c.LintAssertNotNil, + "S1021": c.LintDeclareAssign, + "S1022": nil, + "S1023": c.LintRedundantBreak, + "S1024": c.LintTimeUntil, + "S1025": c.LintRedundantSprintf, + "S1026": nil, + "S1027": nil, + "S1028": c.LintErrorsNewSprintf, + "S1029": c.LintRangeStringRunes, + "S1030": c.LintBytesBufferConversions, + "S1031": c.LintNilCheckAroundRange, + } +} + +func (c *Checker) filterGenerated(files []*ast.File) []*ast.File { + if c.CheckGenerated { + return files + } + var out []*ast.File + for _, f := range files { + if !lint.IsGenerated(f) { + out = append(out, f) + } + } + return out +} + +func (c *Checker) LintSingleCaseSelect(j *lint.Job) { + isSingleSelect := func(node ast.Node) bool { + v, ok := node.(*ast.SelectStmt) + if !ok { + return false + } + return len(v.Body.List) == 1 + } + + seen := map[ast.Node]struct{}{} + fn := func(node ast.Node) bool { + switch v := node.(type) { + case *ast.ForStmt: + if len(v.Body.List) != 1 { + return true + } + if !isSingleSelect(v.Body.List[0]) { + return true + } + if _, ok := v.Body.List[0].(*ast.SelectStmt).Body.List[0].(*ast.CommClause).Comm.(*ast.SendStmt); ok { + // Don't suggest using range for channel sends + return true + } + seen[v.Body.List[0]] = struct{}{} + j.Errorf(node, "should use for range instead of for { select {} }") + case *ast.SelectStmt: + if _, ok := seen[v]; ok { + return true + } + if !isSingleSelect(v) { + return true + } + j.Errorf(node, "should use a simple channel send/receive instead of select with a single case") + return true + } + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintLoopCopy(j *lint.Job) { + fn := func(node ast.Node) bool { + loop, ok := node.(*ast.RangeStmt) + if !ok { + return true + } + + if loop.Key == nil { + return true + } + if len(loop.Body.List) != 1 { + return true + } + stmt, ok := loop.Body.List[0].(*ast.AssignStmt) + if !ok { + return true + } + if stmt.Tok != token.ASSIGN || len(stmt.Lhs) != 1 || len(stmt.Rhs) != 1 { + return true + } + lhs, ok := stmt.Lhs[0].(*ast.IndexExpr) + if !ok { + return true + } + if _, ok := j.Program.Info.TypeOf(lhs.X).(*types.Slice); !ok { + return true + } + lidx, ok := lhs.Index.(*ast.Ident) + if !ok { + return true + } + key, ok := loop.Key.(*ast.Ident) + if !ok { + return true + } + if j.Program.Info.TypeOf(lhs) == nil || j.Program.Info.TypeOf(stmt.Rhs[0]) == nil { + return true + } + if j.Program.Info.ObjectOf(lidx) != j.Program.Info.ObjectOf(key) { + return true + } + if !types.Identical(j.Program.Info.TypeOf(lhs), j.Program.Info.TypeOf(stmt.Rhs[0])) { + return true + } + if _, ok := j.Program.Info.TypeOf(loop.X).(*types.Slice); !ok { + return true + } + + if rhs, ok := stmt.Rhs[0].(*ast.IndexExpr); ok { + rx, ok := rhs.X.(*ast.Ident) + _ = rx + if !ok { + return true + } + ridx, ok := rhs.Index.(*ast.Ident) + if !ok { + return true + } + if j.Program.Info.ObjectOf(ridx) != j.Program.Info.ObjectOf(key) { + return true + } + } else if rhs, ok := stmt.Rhs[0].(*ast.Ident); ok { + value, ok := loop.Value.(*ast.Ident) + if !ok { + return true + } + if j.Program.Info.ObjectOf(rhs) != j.Program.Info.ObjectOf(value) { + return true + } + } else { + return true + } + j.Errorf(loop, "should use copy() instead of a loop") + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintIfBoolCmp(j *lint.Job) { + fn := func(node ast.Node) bool { + expr, ok := node.(*ast.BinaryExpr) + if !ok || (expr.Op != token.EQL && expr.Op != token.NEQ) { + return true + } + x := j.IsBoolConst(expr.X) + y := j.IsBoolConst(expr.Y) + if !x && !y { + return true + } + var other ast.Expr + var val bool + if x { + val = j.BoolConst(expr.X) + other = expr.Y + } else { + val = j.BoolConst(expr.Y) + other = expr.X + } + basic, ok := j.Program.Info.TypeOf(other).Underlying().(*types.Basic) + if !ok || basic.Kind() != types.Bool { + return true + } + op := "" + if (expr.Op == token.EQL && !val) || (expr.Op == token.NEQ && val) { + op = "!" + } + r := op + j.Render(other) + l1 := len(r) + r = strings.TrimLeft(r, "!") + if (l1-len(r))%2 == 1 { + r = "!" + r + } + j.Errorf(expr, "should omit comparison to bool constant, can be simplified to %s", r) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintBytesBufferConversions(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok || len(call.Args) != 1 { + return true + } + + argCall, ok := call.Args[0].(*ast.CallExpr) + if !ok { + return true + } + sel, ok := argCall.Fun.(*ast.SelectorExpr) + if !ok { + return true + } + + typ := j.Program.Info.TypeOf(call.Fun) + if typ == types.Universe.Lookup("string").Type() && j.IsCallToAST(call.Args[0], "(*bytes.Buffer).Bytes") { + j.Errorf(call, "should use %v.String() instead of %v", j.Render(sel.X), j.Render(call)) + } else if typ, ok := typ.(*types.Slice); ok && typ.Elem() == types.Universe.Lookup("byte").Type() && j.IsCallToAST(call.Args[0], "(*bytes.Buffer).String") { + j.Errorf(call, "should use %v.Bytes() instead of %v", j.Render(sel.X), j.Render(call)) + } + + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintStringsContains(j *lint.Job) { + // map of value to token to bool value + allowed := map[int64]map[token.Token]bool{ + -1: {token.GTR: true, token.NEQ: true, token.EQL: false}, + 0: {token.GEQ: true, token.LSS: false}, + } + fn := func(node ast.Node) bool { + expr, ok := node.(*ast.BinaryExpr) + if !ok { + return true + } + switch expr.Op { + case token.GEQ, token.GTR, token.NEQ, token.LSS, token.EQL: + default: + return true + } + + value, ok := j.ExprToInt(expr.Y) + if !ok { + return true + } + + allowedOps, ok := allowed[value] + if !ok { + return true + } + b, ok := allowedOps[expr.Op] + if !ok { + return true + } + + call, ok := expr.X.(*ast.CallExpr) + if !ok { + return true + } + sel, ok := call.Fun.(*ast.SelectorExpr) + if !ok { + return true + } + pkgIdent, ok := sel.X.(*ast.Ident) + if !ok { + return true + } + funIdent := sel.Sel + if pkgIdent.Name != "strings" && pkgIdent.Name != "bytes" { + return true + } + newFunc := "" + switch funIdent.Name { + case "IndexRune": + newFunc = "ContainsRune" + case "IndexAny": + newFunc = "ContainsAny" + case "Index": + newFunc = "Contains" + default: + return true + } + + prefix := "" + if !b { + prefix = "!" + } + j.Errorf(node, "should use %s%s.%s(%s) instead", prefix, pkgIdent.Name, newFunc, j.RenderArgs(call.Args)) + + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintBytesCompare(j *lint.Job) { + fn := func(node ast.Node) bool { + expr, ok := node.(*ast.BinaryExpr) + if !ok { + return true + } + if expr.Op != token.NEQ && expr.Op != token.EQL { + return true + } + call, ok := expr.X.(*ast.CallExpr) + if !ok { + return true + } + if !j.IsCallToAST(call, "bytes.Compare") { + return true + } + value, ok := j.ExprToInt(expr.Y) + if !ok || value != 0 { + return true + } + args := j.RenderArgs(call.Args) + prefix := "" + if expr.Op == token.NEQ { + prefix = "!" + } + j.Errorf(node, "should use %sbytes.Equal(%s) instead", prefix, args) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintForTrue(j *lint.Job) { + fn := func(node ast.Node) bool { + loop, ok := node.(*ast.ForStmt) + if !ok { + return true + } + if loop.Init != nil || loop.Post != nil { + return true + } + if !j.IsBoolConst(loop.Cond) || !j.BoolConst(loop.Cond) { + return true + } + j.Errorf(loop, "should use for {} instead of for true {}") + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintRegexpRaw(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + if !j.IsCallToAST(call, "regexp.MustCompile") && + !j.IsCallToAST(call, "regexp.Compile") { + return true + } + sel, ok := call.Fun.(*ast.SelectorExpr) + if !ok { + return true + } + if len(call.Args) != 1 { + // invalid function call + return true + } + lit, ok := call.Args[0].(*ast.BasicLit) + if !ok { + // TODO(dominikh): support string concat, maybe support constants + return true + } + if lit.Kind != token.STRING { + // invalid function call + return true + } + if lit.Value[0] != '"' { + // already a raw string + return true + } + val := lit.Value + if !strings.Contains(val, `\\`) { + return true + } + + bs := false + for _, c := range val { + if !bs && c == '\\' { + bs = true + continue + } + if bs && c == '\\' { + bs = false + continue + } + if bs { + // backslash followed by non-backslash -> escape sequence + return true + } + } + + j.Errorf(call, "should use raw string (`...`) with regexp.%s to avoid having to escape twice", sel.Sel.Name) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintIfReturn(j *lint.Job) { + fn := func(node ast.Node) bool { + block, ok := node.(*ast.BlockStmt) + if !ok { + return true + } + l := len(block.List) + if l < 2 { + return true + } + n1, n2 := block.List[l-2], block.List[l-1] + + if len(block.List) >= 3 { + if _, ok := block.List[l-3].(*ast.IfStmt); ok { + // Do not flag a series of if statements + return true + } + } + // if statement with no init, no else, a single condition + // checking an identifier or function call and just a return + // statement in the body, that returns a boolean constant + ifs, ok := n1.(*ast.IfStmt) + if !ok { + return true + } + if ifs.Else != nil || ifs.Init != nil { + return true + } + if len(ifs.Body.List) != 1 { + return true + } + if op, ok := ifs.Cond.(*ast.BinaryExpr); ok { + switch op.Op { + case token.EQL, token.LSS, token.GTR, token.NEQ, token.LEQ, token.GEQ: + default: + return true + } + } + ret1, ok := ifs.Body.List[0].(*ast.ReturnStmt) + if !ok { + return true + } + if len(ret1.Results) != 1 { + return true + } + if !j.IsBoolConst(ret1.Results[0]) { + return true + } + + ret2, ok := n2.(*ast.ReturnStmt) + if !ok { + return true + } + if len(ret2.Results) != 1 { + return true + } + if !j.IsBoolConst(ret2.Results[0]) { + return true + } + j.Errorf(n1, "should use 'return <expr>' instead of 'if <expr> { return <bool> }; return <bool>'") + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +// LintRedundantNilCheckWithLen checks for the following reduntant nil-checks: +// +// if x == nil || len(x) == 0 {} +// if x != nil && len(x) != 0 {} +// if x != nil && len(x) == N {} (where N != 0) +// if x != nil && len(x) > N {} +// if x != nil && len(x) >= N {} (where N != 0) +// +func (c *Checker) LintRedundantNilCheckWithLen(j *lint.Job) { + isConstZero := func(expr ast.Expr) (isConst bool, isZero bool) { + _, ok := expr.(*ast.BasicLit) + if ok { + return true, lint.IsZero(expr) + } + id, ok := expr.(*ast.Ident) + if !ok { + return false, false + } + c, ok := j.Program.Info.ObjectOf(id).(*types.Const) + if !ok { + return false, false + } + return true, c.Val().Kind() == constant.Int && c.Val().String() == "0" + } + + fn := func(node ast.Node) bool { + // check that expr is "x || y" or "x && y" + expr, ok := node.(*ast.BinaryExpr) + if !ok { + return true + } + if expr.Op != token.LOR && expr.Op != token.LAND { + return true + } + eqNil := expr.Op == token.LOR + + // check that x is "xx == nil" or "xx != nil" + x, ok := expr.X.(*ast.BinaryExpr) + if !ok { + return true + } + if eqNil && x.Op != token.EQL { + return true + } + if !eqNil && x.Op != token.NEQ { + return true + } + xx, ok := x.X.(*ast.Ident) + if !ok { + return true + } + if !j.IsNil(x.Y) { + return true + } + + // check that y is "len(xx) == 0" or "len(xx) ... " + y, ok := expr.Y.(*ast.BinaryExpr) + if !ok { + return true + } + if eqNil && y.Op != token.EQL { // must be len(xx) *==* 0 + return false + } + yx, ok := y.X.(*ast.CallExpr) + if !ok { + return true + } + yxFun, ok := yx.Fun.(*ast.Ident) + if !ok || yxFun.Name != "len" || len(yx.Args) != 1 { + return true + } + yxArg, ok := yx.Args[0].(*ast.Ident) + if !ok { + return true + } + if yxArg.Name != xx.Name { + return true + } + + if eqNil && !lint.IsZero(y.Y) { // must be len(x) == *0* + return true + } + + if !eqNil { + isConst, isZero := isConstZero(y.Y) + if !isConst { + return true + } + switch y.Op { + case token.EQL: + // avoid false positive for "xx != nil && len(xx) == 0" + if isZero { + return true + } + case token.GEQ: + // avoid false positive for "xx != nil && len(xx) >= 0" + if isZero { + return true + } + case token.NEQ: + // avoid false positive for "xx != nil && len(xx) != <non-zero>" + if !isZero { + return true + } + case token.GTR: + // ok + default: + return true + } + } + + // finally check that xx type is one of array, slice, map or chan + // this is to prevent false positive in case if xx is a pointer to an array + var nilType string + switch j.Program.Info.TypeOf(xx).(type) { + case *types.Slice: + nilType = "nil slices" + case *types.Map: + nilType = "nil maps" + case *types.Chan: + nilType = "nil channels" + default: + return true + } + j.Errorf(expr, "should omit nil check; len() for %s is defined as zero", nilType) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintSlicing(j *lint.Job) { + fn := func(node ast.Node) bool { + n, ok := node.(*ast.SliceExpr) + if !ok { + return true + } + if n.Max != nil { + return true + } + s, ok := n.X.(*ast.Ident) + if !ok || s.Obj == nil { + return true + } + call, ok := n.High.(*ast.CallExpr) + if !ok || len(call.Args) != 1 || call.Ellipsis.IsValid() { + return true + } + fun, ok := call.Fun.(*ast.Ident) + if !ok || fun.Name != "len" { + return true + } + if _, ok := j.Program.Info.ObjectOf(fun).(*types.Builtin); !ok { + return true + } + arg, ok := call.Args[0].(*ast.Ident) + if !ok || arg.Obj != s.Obj { + return true + } + j.Errorf(n, "should omit second index in slice, s[a:len(s)] is identical to s[a:]") + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func refersTo(info *types.Info, expr ast.Expr, ident *ast.Ident) bool { + found := false + fn := func(node ast.Node) bool { + ident2, ok := node.(*ast.Ident) + if !ok { + return true + } + if info.ObjectOf(ident) == info.ObjectOf(ident2) { + found = true + return false + } + return true + } + ast.Inspect(expr, fn) + return found +} + +func (c *Checker) LintLoopAppend(j *lint.Job) { + fn := func(node ast.Node) bool { + loop, ok := node.(*ast.RangeStmt) + if !ok { + return true + } + if !lint.IsBlank(loop.Key) { + return true + } + val, ok := loop.Value.(*ast.Ident) + if !ok { + return true + } + if len(loop.Body.List) != 1 { + return true + } + stmt, ok := loop.Body.List[0].(*ast.AssignStmt) + if !ok { + return true + } + if stmt.Tok != token.ASSIGN || len(stmt.Lhs) != 1 || len(stmt.Rhs) != 1 { + return true + } + if refersTo(j.Program.Info, stmt.Lhs[0], val) { + return true + } + call, ok := stmt.Rhs[0].(*ast.CallExpr) + if !ok { + return true + } + if len(call.Args) != 2 || call.Ellipsis.IsValid() { + return true + } + fun, ok := call.Fun.(*ast.Ident) + if !ok { + return true + } + obj := j.Program.Info.ObjectOf(fun) + fn, ok := obj.(*types.Builtin) + if !ok || fn.Name() != "append" { + return true + } + + src := j.Program.Info.TypeOf(loop.X) + dst := j.Program.Info.TypeOf(call.Args[0]) + // TODO(dominikh) remove nil check once Go issue #15173 has + // been fixed + if src == nil { + return true + } + if !types.Identical(src, dst) { + return true + } + + if j.Render(stmt.Lhs[0]) != j.Render(call.Args[0]) { + return true + } + + el, ok := call.Args[1].(*ast.Ident) + if !ok { + return true + } + if j.Program.Info.ObjectOf(val) != j.Program.Info.ObjectOf(el) { + return true + } + j.Errorf(loop, "should replace loop with %s = append(%s, %s...)", + j.Render(stmt.Lhs[0]), j.Render(call.Args[0]), j.Render(loop.X)) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintTimeSince(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + sel, ok := call.Fun.(*ast.SelectorExpr) + if !ok { + return true + } + if !j.IsCallToAST(sel.X, "time.Now") { + return true + } + if sel.Sel.Name != "Sub" { + return true + } + j.Errorf(call, "should use time.Since instead of time.Now().Sub") + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintTimeUntil(j *lint.Job) { + if !j.IsGoVersion(8) { + return + } + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + if !j.IsCallToAST(call, "(time.Time).Sub") { + return true + } + if !j.IsCallToAST(call.Args[0], "time.Now") { + return true + } + j.Errorf(call, "should use time.Until instead of t.Sub(time.Now())") + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintSimplerReturn(j *lint.Job) { + fn1 := func(node ast.Node) bool { + var ret *ast.FieldList + switch x := node.(type) { + case *ast.FuncDecl: + ret = x.Type.Results + case *ast.FuncLit: + ret = x.Type.Results + default: + return true + } + if ret == nil { + return true + } + + fn2 := func(node ast.Node) bool { + block, ok := node.(*ast.BlockStmt) + if !ok { + return true + } + if len(block.List) < 2 { + return true + } + + outer: + for i, stmt := range block.List { + if i == len(block.List)-1 { + break + } + if i > 0 { + // don't flag an if in a series of ifs + if _, ok := block.List[i-1].(*ast.IfStmt); ok { + continue + } + } + + // if <id1> != nil + ifs, ok := stmt.(*ast.IfStmt) + if !ok || len(ifs.Body.List) != 1 || ifs.Else != nil { + continue + } + expr, ok := ifs.Cond.(*ast.BinaryExpr) + if !ok || expr.Op != token.NEQ || !j.IsNil(expr.Y) { + continue + } + id1, ok := expr.X.(*ast.Ident) + if !ok { + continue + } + + // return ..., <id1> + ret1, ok := ifs.Body.List[0].(*ast.ReturnStmt) + if !ok || len(ret1.Results) == 0 { + continue + } + var results1 []types.Object + for _, res := range ret1.Results { + ident, ok := res.(*ast.Ident) + if !ok { + continue outer + } + results1 = append(results1, j.Program.Info.ObjectOf(ident)) + } + if results1[len(results1)-1] != j.Program.Info.ObjectOf(id1) { + continue + } + + // return ..., [<id1> | nil] + ret2, ok := block.List[i+1].(*ast.ReturnStmt) + if !ok || len(ret2.Results) == 0 { + continue + } + var results2 []types.Object + for _, res := range ret2.Results { + ident, ok := res.(*ast.Ident) + if !ok { + continue outer + } + results2 = append(results2, j.Program.Info.ObjectOf(ident)) + } + _, isNil := results2[len(results2)-1].(*types.Nil) + if results2[len(results2)-1] != j.Program.Info.ObjectOf(id1) && + !isNil { + continue + } + for i, v := range results1[:len(results1)-1] { + if v != results2[i] { + continue outer + } + } + + id1Obj := j.Program.Info.ObjectOf(id1) + if id1Obj == nil { + continue + } + _, idIface := id1Obj.Type().Underlying().(*types.Interface) + _, retIface := j.Program.Info.TypeOf(ret.List[len(ret.List)-1].Type).Underlying().(*types.Interface) + + if retIface && !idIface { + // When the return value is an interface, but the + // identifier is not, an explicit check for nil is + // required to return an untyped nil. + continue + } + + j.Errorf(ifs, "'if %s != nil { return %s }; return %s' can be simplified to 'return %s'", + j.Render(expr.X), j.RenderArgs(ret1.Results), + j.RenderArgs(ret2.Results), j.RenderArgs(ret1.Results)) + } + return true + } + ast.Inspect(node, fn2) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn1) + } +} + +func (c *Checker) LintUnnecessaryBlank(j *lint.Job) { + fn1 := func(node ast.Node) { + assign, ok := node.(*ast.AssignStmt) + if !ok { + return + } + if len(assign.Lhs) != 2 || len(assign.Rhs) != 1 { + return + } + if !lint.IsBlank(assign.Lhs[1]) { + return + } + switch rhs := assign.Rhs[0].(type) { + case *ast.IndexExpr: + // The type-checker should make sure that it's a map, but + // let's be safe. + if _, ok := j.Program.Info.TypeOf(rhs.X).Underlying().(*types.Map); !ok { + return + } + case *ast.UnaryExpr: + if rhs.Op != token.ARROW { + return + } + default: + return + } + cp := *assign + cp.Lhs = cp.Lhs[0:1] + j.Errorf(assign, "should write %s instead of %s", j.Render(&cp), j.Render(assign)) + } + + fn2 := func(node ast.Node) { + stmt, ok := node.(*ast.AssignStmt) + if !ok { + return + } + if len(stmt.Lhs) != len(stmt.Rhs) { + return + } + for i, lh := range stmt.Lhs { + rh := stmt.Rhs[i] + if !lint.IsBlank(lh) { + continue + } + expr, ok := rh.(*ast.UnaryExpr) + if !ok { + continue + } + if expr.Op != token.ARROW { + continue + } + j.Errorf(lh, "'_ = <-ch' can be simplified to '<-ch'") + } + } + + fn3 := func(node ast.Node) { + rs, ok := node.(*ast.RangeStmt) + if !ok { + return + } + if lint.IsBlank(rs.Key) && (rs.Value == nil || lint.IsBlank(rs.Value)) { + j.Errorf(rs.Key, "should omit values from range; this loop is equivalent to `for range ...`") + } + } + + fn := func(node ast.Node) bool { + fn1(node) + fn2(node) + if j.IsGoVersion(4) { + fn3(node) + } + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintSimplerStructConversion(j *lint.Job) { + var skip ast.Node + fn := func(node ast.Node) bool { + // Do not suggest type conversion between pointers + if unary, ok := node.(*ast.UnaryExpr); ok && unary.Op == token.AND { + if lit, ok := unary.X.(*ast.CompositeLit); ok { + skip = lit + } + return true + } + + if node == skip { + return true + } + + lit, ok := node.(*ast.CompositeLit) + if !ok { + return true + } + typ1, _ := j.Program.Info.TypeOf(lit.Type).(*types.Named) + if typ1 == nil { + return true + } + s1, ok := typ1.Underlying().(*types.Struct) + if !ok { + return true + } + + var typ2 *types.Named + var ident *ast.Ident + getSelType := func(expr ast.Expr) (types.Type, *ast.Ident, bool) { + sel, ok := expr.(*ast.SelectorExpr) + if !ok { + return nil, nil, false + } + ident, ok := sel.X.(*ast.Ident) + if !ok { + return nil, nil, false + } + typ := j.Program.Info.TypeOf(sel.X) + return typ, ident, typ != nil + } + if len(lit.Elts) == 0 { + return true + } + if s1.NumFields() != len(lit.Elts) { + return true + } + for i, elt := range lit.Elts { + var t types.Type + var id *ast.Ident + var ok bool + switch elt := elt.(type) { + case *ast.SelectorExpr: + t, id, ok = getSelType(elt) + if !ok { + return true + } + if i >= s1.NumFields() || s1.Field(i).Name() != elt.Sel.Name { + return true + } + case *ast.KeyValueExpr: + var sel *ast.SelectorExpr + sel, ok = elt.Value.(*ast.SelectorExpr) + if !ok { + return true + } + + if elt.Key.(*ast.Ident).Name != sel.Sel.Name { + return true + } + t, id, ok = getSelType(elt.Value) + } + if !ok { + return true + } + // All fields must be initialized from the same object + if ident != nil && ident.Obj != id.Obj { + return true + } + typ2, _ = t.(*types.Named) + if typ2 == nil { + return true + } + ident = id + } + + if typ2 == nil { + return true + } + + if typ1.Obj().Pkg() != typ2.Obj().Pkg() { + // Do not suggest type conversions between different + // packages. Types in different packages might only match + // by coincidence. Furthermore, if the dependency ever + // adds more fields to its type, it could break the code + // that relies on the type conversion to work. + return true + } + + s2, ok := typ2.Underlying().(*types.Struct) + if !ok { + return true + } + if typ1 == typ2 { + return true + } + if !structsIdentical(s1, s2) { + return true + } + j.Errorf(node, "should convert %s (type %s) to %s instead of using struct literal", + ident.Name, typ2.Obj().Name(), typ1.Obj().Name()) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintTrim(j *lint.Job) { + sameNonDynamic := func(node1, node2 ast.Node) bool { + if reflect.TypeOf(node1) != reflect.TypeOf(node2) { + return false + } + + switch node1 := node1.(type) { + case *ast.Ident: + return node1.Obj == node2.(*ast.Ident).Obj + case *ast.SelectorExpr: + return j.Render(node1) == j.Render(node2) + case *ast.IndexExpr: + return j.Render(node1) == j.Render(node2) + } + return false + } + + isLenOnIdent := func(fn ast.Expr, ident ast.Expr) bool { + call, ok := fn.(*ast.CallExpr) + if !ok { + return false + } + if fn, ok := call.Fun.(*ast.Ident); !ok || fn.Name != "len" { + return false + } + if len(call.Args) != 1 { + return false + } + return sameNonDynamic(call.Args[0], ident) + } + + fn := func(node ast.Node) bool { + var pkg string + var fun string + + ifstmt, ok := node.(*ast.IfStmt) + if !ok { + return true + } + if ifstmt.Init != nil { + return true + } + if ifstmt.Else != nil { + return true + } + if len(ifstmt.Body.List) != 1 { + return true + } + condCall, ok := ifstmt.Cond.(*ast.CallExpr) + if !ok { + return true + } + call, ok := condCall.Fun.(*ast.SelectorExpr) + if !ok { + return true + } + if lint.IsIdent(call.X, "strings") { + pkg = "strings" + } else if lint.IsIdent(call.X, "bytes") { + pkg = "bytes" + } else { + return true + } + if lint.IsIdent(call.Sel, "HasPrefix") { + fun = "HasPrefix" + } else if lint.IsIdent(call.Sel, "HasSuffix") { + fun = "HasSuffix" + } else { + return true + } + + assign, ok := ifstmt.Body.List[0].(*ast.AssignStmt) + if !ok { + return true + } + if assign.Tok != token.ASSIGN { + return true + } + if len(assign.Lhs) != 1 || len(assign.Rhs) != 1 { + return true + } + if !sameNonDynamic(condCall.Args[0], assign.Lhs[0]) { + return true + } + slice, ok := assign.Rhs[0].(*ast.SliceExpr) + if !ok { + return true + } + if slice.Slice3 { + return true + } + if !sameNonDynamic(slice.X, condCall.Args[0]) { + return true + } + var index ast.Expr + switch fun { + case "HasPrefix": + // TODO(dh) We could detect a High that is len(s), but another + // rule will already flag that, anyway. + if slice.High != nil { + return true + } + index = slice.Low + case "HasSuffix": + if slice.Low != nil { + n, ok := j.ExprToInt(slice.Low) + if !ok || n != 0 { + return true + } + } + index = slice.High + } + + switch index := index.(type) { + case *ast.CallExpr: + if fun != "HasPrefix" { + return true + } + if fn, ok := index.Fun.(*ast.Ident); !ok || fn.Name != "len" { + return true + } + if len(index.Args) != 1 { + return true + } + id3 := index.Args[0] + switch oid3 := condCall.Args[1].(type) { + case *ast.BasicLit: + if pkg != "strings" { + return false + } + lit, ok := id3.(*ast.BasicLit) + if !ok { + return true + } + s1, ok1 := j.ExprToString(lit) + s2, ok2 := j.ExprToString(condCall.Args[1]) + if !ok1 || !ok2 || s1 != s2 { + return true + } + default: + if !sameNonDynamic(id3, oid3) { + return true + } + } + case *ast.BasicLit, *ast.Ident: + if fun != "HasPrefix" { + return true + } + if pkg != "strings" { + return true + } + string, ok1 := j.ExprToString(condCall.Args[1]) + int, ok2 := j.ExprToInt(slice.Low) + if !ok1 || !ok2 || int != int64(len(string)) { + return true + } + case *ast.BinaryExpr: + if fun != "HasSuffix" { + return true + } + if index.Op != token.SUB { + return true + } + if !isLenOnIdent(index.X, condCall.Args[0]) || + !isLenOnIdent(index.Y, condCall.Args[1]) { + return true + } + default: + return true + } + + var replacement string + switch fun { + case "HasPrefix": + replacement = "TrimPrefix" + case "HasSuffix": + replacement = "TrimSuffix" + } + j.Errorf(ifstmt, "should replace this if statement with an unconditional %s.%s", pkg, replacement) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintLoopSlide(j *lint.Job) { + // TODO(dh): detect bs[i+offset] in addition to bs[offset+i] + // TODO(dh): consider merging this function with LintLoopCopy + // TODO(dh): detect length that is an expression, not a variable name + // TODO(dh): support sliding to a different offset than the beginning of the slice + + fn := func(node ast.Node) bool { + /* + for i := 0; i < n; i++ { + bs[i] = bs[offset+i] + } + + ↓ + + copy(bs[:n], bs[offset:offset+n]) + */ + + loop, ok := node.(*ast.ForStmt) + if !ok || len(loop.Body.List) != 1 || loop.Init == nil || loop.Cond == nil || loop.Post == nil { + return true + } + assign, ok := loop.Init.(*ast.AssignStmt) + if !ok || len(assign.Lhs) != 1 || len(assign.Rhs) != 1 || !lint.IsZero(assign.Rhs[0]) { + return true + } + initvar, ok := assign.Lhs[0].(*ast.Ident) + if !ok { + return true + } + post, ok := loop.Post.(*ast.IncDecStmt) + if !ok || post.Tok != token.INC { + return true + } + postvar, ok := post.X.(*ast.Ident) + if !ok || j.Program.Info.ObjectOf(postvar) != j.Program.Info.ObjectOf(initvar) { + return true + } + bin, ok := loop.Cond.(*ast.BinaryExpr) + if !ok || bin.Op != token.LSS { + return true + } + binx, ok := bin.X.(*ast.Ident) + if !ok || j.Program.Info.ObjectOf(binx) != j.Program.Info.ObjectOf(initvar) { + return true + } + biny, ok := bin.Y.(*ast.Ident) + if !ok { + return true + } + + assign, ok = loop.Body.List[0].(*ast.AssignStmt) + if !ok || len(assign.Lhs) != 1 || len(assign.Rhs) != 1 || assign.Tok != token.ASSIGN { + return true + } + lhs, ok := assign.Lhs[0].(*ast.IndexExpr) + if !ok { + return true + } + rhs, ok := assign.Rhs[0].(*ast.IndexExpr) + if !ok { + return true + } + + bs1, ok := lhs.X.(*ast.Ident) + if !ok { + return true + } + bs2, ok := rhs.X.(*ast.Ident) + if !ok { + return true + } + obj1 := j.Program.Info.ObjectOf(bs1) + obj2 := j.Program.Info.ObjectOf(bs2) + if obj1 != obj2 { + return true + } + if _, ok := obj1.Type().Underlying().(*types.Slice); !ok { + return true + } + + index1, ok := lhs.Index.(*ast.Ident) + if !ok || j.Program.Info.ObjectOf(index1) != j.Program.Info.ObjectOf(initvar) { + return true + } + index2, ok := rhs.Index.(*ast.BinaryExpr) + if !ok || index2.Op != token.ADD { + return true + } + add1, ok := index2.X.(*ast.Ident) + if !ok { + return true + } + add2, ok := index2.Y.(*ast.Ident) + if !ok || j.Program.Info.ObjectOf(add2) != j.Program.Info.ObjectOf(initvar) { + return true + } + + j.Errorf(loop, "should use copy(%s[:%s], %s[%s:]) instead", j.Render(bs1), j.Render(biny), j.Render(bs1), j.Render(add1)) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintMakeLenCap(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + if fn, ok := call.Fun.(*ast.Ident); !ok || fn.Name != "make" { + // FIXME check whether make is indeed the built-in function + return true + } + switch len(call.Args) { + case 2: + // make(T, len) + if _, ok := j.Program.Info.TypeOf(call.Args[0]).Underlying().(*types.Slice); ok { + break + } + if lint.IsZero(call.Args[1]) { + j.Errorf(call.Args[1], "should use make(%s) instead", j.Render(call.Args[0])) + } + case 3: + // make(T, len, cap) + if j.Render(call.Args[1]) == j.Render(call.Args[2]) { + j.Errorf(call.Args[1], "should use make(%s, %s) instead", j.Render(call.Args[0]), j.Render(call.Args[1])) + } + } + return false + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintAssertNotNil(j *lint.Job) { + isNilCheck := func(ident *ast.Ident, expr ast.Expr) bool { + xbinop, ok := expr.(*ast.BinaryExpr) + if !ok || xbinop.Op != token.NEQ { + return false + } + xident, ok := xbinop.X.(*ast.Ident) + if !ok || xident.Obj != ident.Obj { + return false + } + if !j.IsNil(xbinop.Y) { + return false + } + return true + } + isOKCheck := func(ident *ast.Ident, expr ast.Expr) bool { + yident, ok := expr.(*ast.Ident) + if !ok || yident.Obj != ident.Obj { + return false + } + return true + } + fn := func(node ast.Node) bool { + ifstmt, ok := node.(*ast.IfStmt) + if !ok { + return true + } + assign, ok := ifstmt.Init.(*ast.AssignStmt) + if !ok || len(assign.Lhs) != 2 || len(assign.Rhs) != 1 || !lint.IsBlank(assign.Lhs[0]) { + return true + } + assert, ok := assign.Rhs[0].(*ast.TypeAssertExpr) + if !ok { + return true + } + binop, ok := ifstmt.Cond.(*ast.BinaryExpr) + if !ok || binop.Op != token.LAND { + return true + } + assertIdent, ok := assert.X.(*ast.Ident) + if !ok { + return true + } + assignIdent, ok := assign.Lhs[1].(*ast.Ident) + if !ok { + return true + } + if !(isNilCheck(assertIdent, binop.X) && isOKCheck(assignIdent, binop.Y)) && + !(isNilCheck(assertIdent, binop.Y) && isOKCheck(assignIdent, binop.X)) { + return true + } + j.Errorf(ifstmt, "when %s is true, %s can't be nil", j.Render(assignIdent), j.Render(assertIdent)) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintDeclareAssign(j *lint.Job) { + fn := func(node ast.Node) bool { + block, ok := node.(*ast.BlockStmt) + if !ok { + return true + } + if len(block.List) < 2 { + return true + } + for i, stmt := range block.List[:len(block.List)-1] { + _ = i + decl, ok := stmt.(*ast.DeclStmt) + if !ok { + continue + } + gdecl, ok := decl.Decl.(*ast.GenDecl) + if !ok || gdecl.Tok != token.VAR || len(gdecl.Specs) != 1 { + continue + } + vspec, ok := gdecl.Specs[0].(*ast.ValueSpec) + if !ok || len(vspec.Names) != 1 || len(vspec.Values) != 0 { + continue + } + + assign, ok := block.List[i+1].(*ast.AssignStmt) + if !ok || assign.Tok != token.ASSIGN { + continue + } + if len(assign.Lhs) != 1 || len(assign.Rhs) != 1 { + continue + } + ident, ok := assign.Lhs[0].(*ast.Ident) + if !ok { + continue + } + if vspec.Names[0].Obj != ident.Obj { + continue + } + + if refersTo(j.Program.Info, assign.Rhs[0], ident) { + continue + } + j.Errorf(decl, "should merge variable declaration with assignment on next line") + } + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintRedundantBreak(j *lint.Job) { + fn1 := func(node ast.Node) { + clause, ok := node.(*ast.CaseClause) + if !ok { + return + } + if len(clause.Body) < 2 { + return + } + branch, ok := clause.Body[len(clause.Body)-1].(*ast.BranchStmt) + if !ok || branch.Tok != token.BREAK || branch.Label != nil { + return + } + j.Errorf(branch, "redundant break statement") + return + } + fn2 := func(node ast.Node) { + var ret *ast.FieldList + var body *ast.BlockStmt + switch x := node.(type) { + case *ast.FuncDecl: + ret = x.Type.Results + body = x.Body + case *ast.FuncLit: + ret = x.Type.Results + body = x.Body + default: + return + } + // if the func has results, a return can't be redundant. + // similarly, if there are no statements, there can be + // no return. + if ret != nil || body == nil || len(body.List) < 1 { + return + } + rst, ok := body.List[len(body.List)-1].(*ast.ReturnStmt) + if !ok { + return + } + // we don't need to check rst.Results as we already + // checked x.Type.Results to be nil. + j.Errorf(rst, "redundant return statement") + } + fn := func(node ast.Node) bool { + fn1(node) + fn2(node) + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) Implements(j *lint.Job, typ types.Type, iface string) bool { + // OPT(dh): we can cache the type lookup + idx := strings.IndexRune(iface, '.') + var scope *types.Scope + var ifaceName string + if idx == -1 { + scope = types.Universe + ifaceName = iface + } else { + pkgName := iface[:idx] + pkg := j.Program.Prog.Package(pkgName) + if pkg == nil { + return false + } + scope = pkg.Pkg.Scope() + ifaceName = iface[idx+1:] + } + + obj := scope.Lookup(ifaceName) + if obj == nil { + return false + } + i, ok := obj.Type().Underlying().(*types.Interface) + if !ok { + return false + } + return types.Implements(typ, i) +} + +func (c *Checker) LintRedundantSprintf(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + if !j.IsCallToAST(call, "fmt.Sprintf") { + return true + } + if len(call.Args) != 2 { + return true + } + if s, ok := j.ExprToString(call.Args[0]); !ok || s != "%s" { + return true + } + pkg := j.NodePackage(call) + arg := call.Args[1] + typ := pkg.Info.TypeOf(arg) + + if c.Implements(j, typ, "fmt.Stringer") { + j.Errorf(call, "should use String() instead of fmt.Sprintf") + return true + } + + if typ.Underlying() == types.Universe.Lookup("string").Type() { + if typ == types.Universe.Lookup("string").Type() { + j.Errorf(call, "the argument is already a string, there's no need to use fmt.Sprintf") + } else { + j.Errorf(call, "the argument's underlying type is a string, should use a simple conversion instead of fmt.Sprintf") + } + } + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintErrorsNewSprintf(j *lint.Job) { + fn := func(node ast.Node) bool { + if !j.IsCallToAST(node, "errors.New") { + return true + } + call := node.(*ast.CallExpr) + if !j.IsCallToAST(call.Args[0], "fmt.Sprintf") { + return true + } + j.Errorf(node, "should use fmt.Errorf(...) instead of errors.New(fmt.Sprintf(...))") + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) LintRangeStringRunes(j *lint.Job) { + sharedcheck.CheckRangeStringRunes(c.nodeFns, j) +} + +func (c *Checker) LintNilCheckAroundRange(j *lint.Job) { + fn := func(node ast.Node) bool { + ifstmt, ok := node.(*ast.IfStmt) + if !ok { + return true + } + + cond, ok := ifstmt.Cond.(*ast.BinaryExpr) + if !ok { + return true + } + + if cond.Op != token.NEQ || !j.IsNil(cond.Y) || len(ifstmt.Body.List) != 1 { + return true + } + + loop, ok := ifstmt.Body.List[0].(*ast.RangeStmt) + if !ok { + return true + } + ifXIdent, ok := cond.X.(*ast.Ident) + if !ok { + return true + } + rangeXIdent, ok := loop.X.(*ast.Ident) + if !ok { + return true + } + if ifXIdent.Obj != rangeXIdent.Obj { + return true + } + switch j.Program.Info.TypeOf(rangeXIdent).(type) { + case *types.Slice, *types.Map: + j.Errorf(node, "unnecessary nil check around range") + } + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} diff --git a/vendor/honnef.co/go/tools/simple/lint17.go b/vendor/honnef.co/go/tools/simple/lint17.go new file mode 100644 index 0000000..53f529c --- /dev/null +++ b/vendor/honnef.co/go/tools/simple/lint17.go @@ -0,0 +1,7 @@ +// +build !go1.8 + +package simple + +import "go/types" + +var structsIdentical = types.Identical diff --git a/vendor/honnef.co/go/tools/simple/lint18.go b/vendor/honnef.co/go/tools/simple/lint18.go new file mode 100644 index 0000000..ab9ea72 --- /dev/null +++ b/vendor/honnef.co/go/tools/simple/lint18.go @@ -0,0 +1,7 @@ +// +build go1.8 + +package simple + +import "go/types" + +var structsIdentical = types.IdenticalIgnoreTags diff --git a/vendor/honnef.co/go/tools/ssa/LICENSE b/vendor/honnef.co/go/tools/ssa/LICENSE new file mode 100644 index 0000000..aee4804 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/LICENSE @@ -0,0 +1,28 @@ +Copyright (c) 2009 The Go Authors. All rights reserved. +Copyright (c) 2016 Dominik Honnef. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are +met: + + * Redistributions of source code must retain the above copyright +notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above +copyright notice, this list of conditions and the following disclaimer +in the documentation and/or other materials provided with the +distribution. + * Neither the name of Google Inc. nor the names of its +contributors may be used to endorse or promote products derived from +this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/vendor/honnef.co/go/tools/ssa/blockopt.go b/vendor/honnef.co/go/tools/ssa/blockopt.go new file mode 100644 index 0000000..22c9a4c --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/blockopt.go @@ -0,0 +1,195 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssa + +// Simple block optimizations to simplify the control flow graph. + +// TODO(adonovan): opt: instead of creating several "unreachable" blocks +// per function in the Builder, reuse a single one (e.g. at Blocks[1]) +// to reduce garbage. + +import ( + "fmt" + "os" +) + +// If true, perform sanity checking and show progress at each +// successive iteration of optimizeBlocks. Very verbose. +const debugBlockOpt = false + +// markReachable sets Index=-1 for all blocks reachable from b. +func markReachable(b *BasicBlock) { + b.Index = -1 + for _, succ := range b.Succs { + if succ.Index == 0 { + markReachable(succ) + } + } +} + +func DeleteUnreachableBlocks(f *Function) { + deleteUnreachableBlocks(f) +} + +// deleteUnreachableBlocks marks all reachable blocks of f and +// eliminates (nils) all others, including possibly cyclic subgraphs. +// +func deleteUnreachableBlocks(f *Function) { + const white, black = 0, -1 + // We borrow b.Index temporarily as the mark bit. + for _, b := range f.Blocks { + b.Index = white + } + markReachable(f.Blocks[0]) + if f.Recover != nil { + markReachable(f.Recover) + } + for i, b := range f.Blocks { + if b.Index == white { + for _, c := range b.Succs { + if c.Index == black { + c.removePred(b) // delete white->black edge + } + } + if debugBlockOpt { + fmt.Fprintln(os.Stderr, "unreachable", b) + } + f.Blocks[i] = nil // delete b + } + } + f.removeNilBlocks() +} + +// jumpThreading attempts to apply simple jump-threading to block b, +// in which a->b->c become a->c if b is just a Jump. +// The result is true if the optimization was applied. +// +func jumpThreading(f *Function, b *BasicBlock) bool { + if b.Index == 0 { + return false // don't apply to entry block + } + if b.Instrs == nil { + return false + } + if _, ok := b.Instrs[0].(*Jump); !ok { + return false // not just a jump + } + c := b.Succs[0] + if c == b { + return false // don't apply to degenerate jump-to-self. + } + if c.hasPhi() { + return false // not sound without more effort + } + for j, a := range b.Preds { + a.replaceSucc(b, c) + + // If a now has two edges to c, replace its degenerate If by Jump. + if len(a.Succs) == 2 && a.Succs[0] == c && a.Succs[1] == c { + jump := new(Jump) + jump.setBlock(a) + a.Instrs[len(a.Instrs)-1] = jump + a.Succs = a.Succs[:1] + c.removePred(b) + } else { + if j == 0 { + c.replacePred(b, a) + } else { + c.Preds = append(c.Preds, a) + } + } + + if debugBlockOpt { + fmt.Fprintln(os.Stderr, "jumpThreading", a, b, c) + } + } + f.Blocks[b.Index] = nil // delete b + return true +} + +// fuseBlocks attempts to apply the block fusion optimization to block +// a, in which a->b becomes ab if len(a.Succs)==len(b.Preds)==1. +// The result is true if the optimization was applied. +// +func fuseBlocks(f *Function, a *BasicBlock) bool { + if len(a.Succs) != 1 { + return false + } + b := a.Succs[0] + if len(b.Preds) != 1 { + return false + } + + // Degenerate &&/|| ops may result in a straight-line CFG + // containing φ-nodes. (Ideally we'd replace such them with + // their sole operand but that requires Referrers, built later.) + if b.hasPhi() { + return false // not sound without further effort + } + + // Eliminate jump at end of A, then copy all of B across. + a.Instrs = append(a.Instrs[:len(a.Instrs)-1], b.Instrs...) + for _, instr := range b.Instrs { + instr.setBlock(a) + } + + // A inherits B's successors + a.Succs = append(a.succs2[:0], b.Succs...) + + // Fix up Preds links of all successors of B. + for _, c := range b.Succs { + c.replacePred(b, a) + } + + if debugBlockOpt { + fmt.Fprintln(os.Stderr, "fuseBlocks", a, b) + } + + f.Blocks[b.Index] = nil // delete b + return true +} + +func OptimizeBlocks(f *Function) { + optimizeBlocks(f) +} + +// optimizeBlocks() performs some simple block optimizations on a +// completed function: dead block elimination, block fusion, jump +// threading. +// +func optimizeBlocks(f *Function) { + deleteUnreachableBlocks(f) + + // Loop until no further progress. + changed := true + for changed { + changed = false + + if debugBlockOpt { + f.WriteTo(os.Stderr) + mustSanityCheck(f, nil) + } + + for _, b := range f.Blocks { + // f.Blocks will temporarily contain nils to indicate + // deleted blocks; we remove them at the end. + if b == nil { + continue + } + + // Fuse blocks. b->c becomes bc. + if fuseBlocks(f, b) { + changed = true + } + + // a->b->c becomes a->c if b contains only a Jump. + if jumpThreading(f, b) { + changed = true + continue // (b was disconnected) + } + } + } + f.removeNilBlocks() +} diff --git a/vendor/honnef.co/go/tools/ssa/builder.go b/vendor/honnef.co/go/tools/ssa/builder.go new file mode 100644 index 0000000..bfb7a2b --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/builder.go @@ -0,0 +1,2383 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssa + +// This file implements the BUILD phase of SSA construction. +// +// SSA construction has two phases, CREATE and BUILD. In the CREATE phase +// (create.go), all packages are constructed and type-checked and +// definitions of all package members are created, method-sets are +// computed, and wrapper methods are synthesized. +// ssa.Packages are created in arbitrary order. +// +// In the BUILD phase (builder.go), the builder traverses the AST of +// each Go source function and generates SSA instructions for the +// function body. Initializer expressions for package-level variables +// are emitted to the package's init() function in the order specified +// by go/types.Info.InitOrder, then code for each function in the +// package is generated in lexical order. +// The BUILD phases for distinct packages are independent and are +// executed in parallel. +// +// TODO(adonovan): indeed, building functions is now embarrassingly parallel. +// Audit for concurrency then benchmark using more goroutines. +// +// The builder's and Program's indices (maps) are populated and +// mutated during the CREATE phase, but during the BUILD phase they +// remain constant. The sole exception is Prog.methodSets and its +// related maps, which are protected by a dedicated mutex. + +import ( + "fmt" + "go/ast" + exact "go/constant" + "go/token" + "go/types" + "os" + "sync" +) + +type opaqueType struct { + types.Type + name string +} + +func (t *opaqueType) String() string { return t.name } + +var ( + varOk = newVar("ok", tBool) + varIndex = newVar("index", tInt) + + // Type constants. + tBool = types.Typ[types.Bool] + tByte = types.Typ[types.Byte] + tInt = types.Typ[types.Int] + tInvalid = types.Typ[types.Invalid] + tString = types.Typ[types.String] + tUntypedNil = types.Typ[types.UntypedNil] + tRangeIter = &opaqueType{nil, "iter"} // the type of all "range" iterators + tEface = new(types.Interface) + + // SSA Value constants. + vZero = intConst(0) + vOne = intConst(1) + vTrue = NewConst(exact.MakeBool(true), tBool) +) + +// builder holds state associated with the package currently being built. +// Its methods contain all the logic for AST-to-SSA conversion. +type builder struct{} + +// cond emits to fn code to evaluate boolean condition e and jump +// to t or f depending on its value, performing various simplifications. +// +// Postcondition: fn.currentBlock is nil. +// +func (b *builder) cond(fn *Function, e ast.Expr, t, f *BasicBlock) { + switch e := e.(type) { + case *ast.ParenExpr: + b.cond(fn, e.X, t, f) + return + + case *ast.BinaryExpr: + switch e.Op { + case token.LAND: + ltrue := fn.newBasicBlock("cond.true") + b.cond(fn, e.X, ltrue, f) + fn.currentBlock = ltrue + b.cond(fn, e.Y, t, f) + return + + case token.LOR: + lfalse := fn.newBasicBlock("cond.false") + b.cond(fn, e.X, t, lfalse) + fn.currentBlock = lfalse + b.cond(fn, e.Y, t, f) + return + } + + case *ast.UnaryExpr: + if e.Op == token.NOT { + b.cond(fn, e.X, f, t) + return + } + } + + // A traditional compiler would simplify "if false" (etc) here + // but we do not, for better fidelity to the source code. + // + // The value of a constant condition may be platform-specific, + // and may cause blocks that are reachable in some configuration + // to be hidden from subsequent analyses such as bug-finding tools. + emitIf(fn, b.expr(fn, e), t, f) +} + +// logicalBinop emits code to fn to evaluate e, a &&- or +// ||-expression whose reified boolean value is wanted. +// The value is returned. +// +func (b *builder) logicalBinop(fn *Function, e *ast.BinaryExpr) Value { + rhs := fn.newBasicBlock("binop.rhs") + done := fn.newBasicBlock("binop.done") + + // T(e) = T(e.X) = T(e.Y) after untyped constants have been + // eliminated. + // TODO(adonovan): not true; MyBool==MyBool yields UntypedBool. + t := fn.Pkg.typeOf(e) + + var short Value // value of the short-circuit path + switch e.Op { + case token.LAND: + b.cond(fn, e.X, rhs, done) + short = NewConst(exact.MakeBool(false), t) + + case token.LOR: + b.cond(fn, e.X, done, rhs) + short = NewConst(exact.MakeBool(true), t) + } + + // Is rhs unreachable? + if rhs.Preds == nil { + // Simplify false&&y to false, true||y to true. + fn.currentBlock = done + return short + } + + // Is done unreachable? + if done.Preds == nil { + // Simplify true&&y (or false||y) to y. + fn.currentBlock = rhs + return b.expr(fn, e.Y) + } + + // All edges from e.X to done carry the short-circuit value. + var edges []Value + for _ = range done.Preds { + edges = append(edges, short) + } + + // The edge from e.Y to done carries the value of e.Y. + fn.currentBlock = rhs + edges = append(edges, b.expr(fn, e.Y)) + emitJump(fn, done) + fn.currentBlock = done + + phi := &Phi{Edges: edges, Comment: e.Op.String()} + phi.pos = e.OpPos + phi.typ = t + return done.emit(phi) +} + +// exprN lowers a multi-result expression e to SSA form, emitting code +// to fn and returning a single Value whose type is a *types.Tuple. +// The caller must access the components via Extract. +// +// Multi-result expressions include CallExprs in a multi-value +// assignment or return statement, and "value,ok" uses of +// TypeAssertExpr, IndexExpr (when X is a map), and UnaryExpr (when Op +// is token.ARROW). +// +func (b *builder) exprN(fn *Function, e ast.Expr) Value { + typ := fn.Pkg.typeOf(e).(*types.Tuple) + switch e := e.(type) { + case *ast.ParenExpr: + return b.exprN(fn, e.X) + + case *ast.CallExpr: + // Currently, no built-in function nor type conversion + // has multiple results, so we can avoid some of the + // cases for single-valued CallExpr. + var c Call + b.setCall(fn, e, &c.Call) + c.typ = typ + return fn.emit(&c) + + case *ast.IndexExpr: + mapt := fn.Pkg.typeOf(e.X).Underlying().(*types.Map) + lookup := &Lookup{ + X: b.expr(fn, e.X), + Index: emitConv(fn, b.expr(fn, e.Index), mapt.Key()), + CommaOk: true, + } + lookup.setType(typ) + lookup.setPos(e.Lbrack) + return fn.emit(lookup) + + case *ast.TypeAssertExpr: + return emitTypeTest(fn, b.expr(fn, e.X), typ.At(0).Type(), e.Lparen) + + case *ast.UnaryExpr: // must be receive <- + unop := &UnOp{ + Op: token.ARROW, + X: b.expr(fn, e.X), + CommaOk: true, + } + unop.setType(typ) + unop.setPos(e.OpPos) + return fn.emit(unop) + } + panic(fmt.Sprintf("exprN(%T) in %s", e, fn)) +} + +// builtin emits to fn SSA instructions to implement a call to the +// built-in function obj with the specified arguments +// and return type. It returns the value defined by the result. +// +// The result is nil if no special handling was required; in this case +// the caller should treat this like an ordinary library function +// call. +// +func (b *builder) builtin(fn *Function, obj *types.Builtin, args []ast.Expr, typ types.Type, pos token.Pos) Value { + switch obj.Name() { + case "make": + switch typ.Underlying().(type) { + case *types.Slice: + n := b.expr(fn, args[1]) + m := n + if len(args) == 3 { + m = b.expr(fn, args[2]) + } + if m, ok := m.(*Const); ok { + // treat make([]T, n, m) as new([m]T)[:n] + cap := m.Int64() + at := types.NewArray(typ.Underlying().(*types.Slice).Elem(), cap) + alloc := emitNew(fn, at, pos) + alloc.Comment = "makeslice" + v := &Slice{ + X: alloc, + High: n, + } + v.setPos(pos) + v.setType(typ) + return fn.emit(v) + } + v := &MakeSlice{ + Len: n, + Cap: m, + } + v.setPos(pos) + v.setType(typ) + return fn.emit(v) + + case *types.Map: + var res Value + if len(args) == 2 { + res = b.expr(fn, args[1]) + } + v := &MakeMap{Reserve: res} + v.setPos(pos) + v.setType(typ) + return fn.emit(v) + + case *types.Chan: + var sz Value = vZero + if len(args) == 2 { + sz = b.expr(fn, args[1]) + } + v := &MakeChan{Size: sz} + v.setPos(pos) + v.setType(typ) + return fn.emit(v) + } + + case "new": + alloc := emitNew(fn, deref(typ), pos) + alloc.Comment = "new" + return alloc + + case "len", "cap": + // Special case: len or cap of an array or *array is + // based on the type, not the value which may be nil. + // We must still evaluate the value, though. (If it + // was side-effect free, the whole call would have + // been constant-folded.) + t := deref(fn.Pkg.typeOf(args[0])).Underlying() + if at, ok := t.(*types.Array); ok { + b.expr(fn, args[0]) // for effects only + return intConst(at.Len()) + } + // Otherwise treat as normal. + + case "panic": + fn.emit(&Panic{ + X: emitConv(fn, b.expr(fn, args[0]), tEface), + pos: pos, + }) + fn.currentBlock = fn.newBasicBlock("unreachable") + return vTrue // any non-nil Value will do + } + return nil // treat all others as a regular function call +} + +// addr lowers a single-result addressable expression e to SSA form, +// emitting code to fn and returning the location (an lvalue) defined +// by the expression. +// +// If escaping is true, addr marks the base variable of the +// addressable expression e as being a potentially escaping pointer +// value. For example, in this code: +// +// a := A{ +// b: [1]B{B{c: 1}} +// } +// return &a.b[0].c +// +// the application of & causes a.b[0].c to have its address taken, +// which means that ultimately the local variable a must be +// heap-allocated. This is a simple but very conservative escape +// analysis. +// +// Operations forming potentially escaping pointers include: +// - &x, including when implicit in method call or composite literals. +// - a[:] iff a is an array (not *array) +// - references to variables in lexically enclosing functions. +// +func (b *builder) addr(fn *Function, e ast.Expr, escaping bool) lvalue { + switch e := e.(type) { + case *ast.Ident: + if isBlankIdent(e) { + return blank{} + } + obj := fn.Pkg.objectOf(e) + v := fn.Prog.packageLevelValue(obj) // var (address) + if v == nil { + v = fn.lookup(obj, escaping) + } + return &address{addr: v, pos: e.Pos(), expr: e} + + case *ast.CompositeLit: + t := deref(fn.Pkg.typeOf(e)) + var v *Alloc + if escaping { + v = emitNew(fn, t, e.Lbrace) + } else { + v = fn.addLocal(t, e.Lbrace) + } + v.Comment = "complit" + var sb storebuf + b.compLit(fn, v, e, true, &sb) + sb.emit(fn) + return &address{addr: v, pos: e.Lbrace, expr: e} + + case *ast.ParenExpr: + return b.addr(fn, e.X, escaping) + + case *ast.SelectorExpr: + sel, ok := fn.Pkg.info.Selections[e] + if !ok { + // qualified identifier + return b.addr(fn, e.Sel, escaping) + } + if sel.Kind() != types.FieldVal { + panic(sel) + } + wantAddr := true + v := b.receiver(fn, e.X, wantAddr, escaping, sel) + last := len(sel.Index()) - 1 + return &address{ + addr: emitFieldSelection(fn, v, sel.Index()[last], true, e.Sel), + pos: e.Sel.Pos(), + expr: e.Sel, + } + + case *ast.IndexExpr: + var x Value + var et types.Type + switch t := fn.Pkg.typeOf(e.X).Underlying().(type) { + case *types.Array: + x = b.addr(fn, e.X, escaping).address(fn) + et = types.NewPointer(t.Elem()) + case *types.Pointer: // *array + x = b.expr(fn, e.X) + et = types.NewPointer(t.Elem().Underlying().(*types.Array).Elem()) + case *types.Slice: + x = b.expr(fn, e.X) + et = types.NewPointer(t.Elem()) + case *types.Map: + return &element{ + m: b.expr(fn, e.X), + k: emitConv(fn, b.expr(fn, e.Index), t.Key()), + t: t.Elem(), + pos: e.Lbrack, + } + default: + panic("unexpected container type in IndexExpr: " + t.String()) + } + v := &IndexAddr{ + X: x, + Index: emitConv(fn, b.expr(fn, e.Index), tInt), + } + v.setPos(e.Lbrack) + v.setType(et) + return &address{addr: fn.emit(v), pos: e.Lbrack, expr: e} + + case *ast.StarExpr: + return &address{addr: b.expr(fn, e.X), pos: e.Star, expr: e} + } + + panic(fmt.Sprintf("unexpected address expression: %T", e)) +} + +type store struct { + lhs lvalue + rhs Value +} + +type storebuf struct{ stores []store } + +func (sb *storebuf) store(lhs lvalue, rhs Value) { + sb.stores = append(sb.stores, store{lhs, rhs}) +} + +func (sb *storebuf) emit(fn *Function) { + for _, s := range sb.stores { + s.lhs.store(fn, s.rhs) + } +} + +// assign emits to fn code to initialize the lvalue loc with the value +// of expression e. If isZero is true, assign assumes that loc holds +// the zero value for its type. +// +// This is equivalent to loc.store(fn, b.expr(fn, e)), but may generate +// better code in some cases, e.g., for composite literals in an +// addressable location. +// +// If sb is not nil, assign generates code to evaluate expression e, but +// not to update loc. Instead, the necessary stores are appended to the +// storebuf sb so that they can be executed later. This allows correct +// in-place update of existing variables when the RHS is a composite +// literal that may reference parts of the LHS. +// +func (b *builder) assign(fn *Function, loc lvalue, e ast.Expr, isZero bool, sb *storebuf) { + // Can we initialize it in place? + if e, ok := unparen(e).(*ast.CompositeLit); ok { + // A CompositeLit never evaluates to a pointer, + // so if the type of the location is a pointer, + // an &-operation is implied. + if _, ok := loc.(blank); !ok { // avoid calling blank.typ() + if isPointer(loc.typ()) { + ptr := b.addr(fn, e, true).address(fn) + // copy address + if sb != nil { + sb.store(loc, ptr) + } else { + loc.store(fn, ptr) + } + return + } + } + + if _, ok := loc.(*address); ok { + if isInterface(loc.typ()) { + // e.g. var x interface{} = T{...} + // Can't in-place initialize an interface value. + // Fall back to copying. + } else { + // x = T{...} or x := T{...} + addr := loc.address(fn) + if sb != nil { + b.compLit(fn, addr, e, isZero, sb) + } else { + var sb storebuf + b.compLit(fn, addr, e, isZero, &sb) + sb.emit(fn) + } + + // Subtle: emit debug ref for aggregate types only; + // slice and map are handled by store ops in compLit. + switch loc.typ().Underlying().(type) { + case *types.Struct, *types.Array: + emitDebugRef(fn, e, addr, true) + } + + return + } + } + } + + // simple case: just copy + rhs := b.expr(fn, e) + if sb != nil { + sb.store(loc, rhs) + } else { + loc.store(fn, rhs) + } +} + +// expr lowers a single-result expression e to SSA form, emitting code +// to fn and returning the Value defined by the expression. +// +func (b *builder) expr(fn *Function, e ast.Expr) Value { + e = unparen(e) + + tv := fn.Pkg.info.Types[e] + + // Is expression a constant? + if tv.Value != nil { + return NewConst(tv.Value, tv.Type) + } + + var v Value + if tv.Addressable() { + // Prefer pointer arithmetic ({Index,Field}Addr) followed + // by Load over subelement extraction (e.g. Index, Field), + // to avoid large copies. + v = b.addr(fn, e, false).load(fn) + } else { + v = b.expr0(fn, e, tv) + } + if fn.debugInfo() { + emitDebugRef(fn, e, v, false) + } + return v +} + +func (b *builder) expr0(fn *Function, e ast.Expr, tv types.TypeAndValue) Value { + switch e := e.(type) { + case *ast.BasicLit: + panic("non-constant BasicLit") // unreachable + + case *ast.FuncLit: + fn2 := &Function{ + name: fmt.Sprintf("%s$%d", fn.Name(), 1+len(fn.AnonFuncs)), + Signature: fn.Pkg.typeOf(e.Type).Underlying().(*types.Signature), + pos: e.Type.Func, + parent: fn, + Pkg: fn.Pkg, + Prog: fn.Prog, + syntax: e, + } + fn.AnonFuncs = append(fn.AnonFuncs, fn2) + b.buildFunction(fn2) + if fn2.FreeVars == nil { + return fn2 + } + v := &MakeClosure{Fn: fn2} + v.setType(tv.Type) + for _, fv := range fn2.FreeVars { + v.Bindings = append(v.Bindings, fv.outer) + fv.outer = nil + } + return fn.emit(v) + + case *ast.TypeAssertExpr: // single-result form only + return emitTypeAssert(fn, b.expr(fn, e.X), tv.Type, e.Lparen) + + case *ast.CallExpr: + if fn.Pkg.info.Types[e.Fun].IsType() { + // Explicit type conversion, e.g. string(x) or big.Int(x) + x := b.expr(fn, e.Args[0]) + y := emitConv(fn, x, tv.Type) + if y != x { + switch y := y.(type) { + case *Convert: + y.pos = e.Lparen + case *ChangeType: + y.pos = e.Lparen + case *MakeInterface: + y.pos = e.Lparen + } + } + return y + } + // Call to "intrinsic" built-ins, e.g. new, make, panic. + if id, ok := unparen(e.Fun).(*ast.Ident); ok { + if obj, ok := fn.Pkg.info.Uses[id].(*types.Builtin); ok { + if v := b.builtin(fn, obj, e.Args, tv.Type, e.Lparen); v != nil { + return v + } + } + } + // Regular function call. + var v Call + b.setCall(fn, e, &v.Call) + v.setType(tv.Type) + return fn.emit(&v) + + case *ast.UnaryExpr: + switch e.Op { + case token.AND: // &X --- potentially escaping. + addr := b.addr(fn, e.X, true) + if _, ok := unparen(e.X).(*ast.StarExpr); ok { + // &*p must panic if p is nil (http://golang.org/s/go12nil). + // For simplicity, we'll just (suboptimally) rely + // on the side effects of a load. + // TODO(adonovan): emit dedicated nilcheck. + addr.load(fn) + } + return addr.address(fn) + case token.ADD: + return b.expr(fn, e.X) + case token.NOT, token.ARROW, token.SUB, token.XOR: // ! <- - ^ + v := &UnOp{ + Op: e.Op, + X: b.expr(fn, e.X), + } + v.setPos(e.OpPos) + v.setType(tv.Type) + return fn.emit(v) + default: + panic(e.Op) + } + + case *ast.BinaryExpr: + switch e.Op { + case token.LAND, token.LOR: + return b.logicalBinop(fn, e) + case token.SHL, token.SHR: + fallthrough + case token.ADD, token.SUB, token.MUL, token.QUO, token.REM, token.AND, token.OR, token.XOR, token.AND_NOT: + return emitArith(fn, e.Op, b.expr(fn, e.X), b.expr(fn, e.Y), tv.Type, e.OpPos) + + case token.EQL, token.NEQ, token.GTR, token.LSS, token.LEQ, token.GEQ: + cmp := emitCompare(fn, e.Op, b.expr(fn, e.X), b.expr(fn, e.Y), e.OpPos) + // The type of x==y may be UntypedBool. + return emitConv(fn, cmp, DefaultType(tv.Type)) + default: + panic("illegal op in BinaryExpr: " + e.Op.String()) + } + + case *ast.SliceExpr: + var low, high, max Value + var x Value + switch fn.Pkg.typeOf(e.X).Underlying().(type) { + case *types.Array: + // Potentially escaping. + x = b.addr(fn, e.X, true).address(fn) + case *types.Basic, *types.Slice, *types.Pointer: // *array + x = b.expr(fn, e.X) + default: + panic("unreachable") + } + if e.High != nil { + high = b.expr(fn, e.High) + } + if e.Low != nil { + low = b.expr(fn, e.Low) + } + if e.Slice3 { + max = b.expr(fn, e.Max) + } + v := &Slice{ + X: x, + Low: low, + High: high, + Max: max, + } + v.setPos(e.Lbrack) + v.setType(tv.Type) + return fn.emit(v) + + case *ast.Ident: + obj := fn.Pkg.info.Uses[e] + // Universal built-in or nil? + switch obj := obj.(type) { + case *types.Builtin: + return &Builtin{name: obj.Name(), sig: tv.Type.(*types.Signature)} + case *types.Nil: + return nilConst(tv.Type) + } + // Package-level func or var? + if v := fn.Prog.packageLevelValue(obj); v != nil { + if _, ok := obj.(*types.Var); ok { + return emitLoad(fn, v) // var (address) + } + return v // (func) + } + // Local var. + return emitLoad(fn, fn.lookup(obj, false)) // var (address) + + case *ast.SelectorExpr: + sel, ok := fn.Pkg.info.Selections[e] + if !ok { + // qualified identifier + return b.expr(fn, e.Sel) + } + switch sel.Kind() { + case types.MethodExpr: + // (*T).f or T.f, the method f from the method-set of type T. + // The result is a "thunk". + return emitConv(fn, makeThunk(fn.Prog, sel), tv.Type) + + case types.MethodVal: + // e.f where e is an expression and f is a method. + // The result is a "bound". + obj := sel.Obj().(*types.Func) + rt := recvType(obj) + wantAddr := isPointer(rt) + escaping := true + v := b.receiver(fn, e.X, wantAddr, escaping, sel) + if isInterface(rt) { + // If v has interface type I, + // we must emit a check that v is non-nil. + // We use: typeassert v.(I). + emitTypeAssert(fn, v, rt, token.NoPos) + } + c := &MakeClosure{ + Fn: makeBound(fn.Prog, obj), + Bindings: []Value{v}, + } + c.setPos(e.Sel.Pos()) + c.setType(tv.Type) + return fn.emit(c) + + case types.FieldVal: + indices := sel.Index() + last := len(indices) - 1 + v := b.expr(fn, e.X) + v = emitImplicitSelections(fn, v, indices[:last]) + v = emitFieldSelection(fn, v, indices[last], false, e.Sel) + return v + } + + panic("unexpected expression-relative selector") + + case *ast.IndexExpr: + switch t := fn.Pkg.typeOf(e.X).Underlying().(type) { + case *types.Array: + // Non-addressable array (in a register). + v := &Index{ + X: b.expr(fn, e.X), + Index: emitConv(fn, b.expr(fn, e.Index), tInt), + } + v.setPos(e.Lbrack) + v.setType(t.Elem()) + return fn.emit(v) + + case *types.Map: + // Maps are not addressable. + mapt := fn.Pkg.typeOf(e.X).Underlying().(*types.Map) + v := &Lookup{ + X: b.expr(fn, e.X), + Index: emitConv(fn, b.expr(fn, e.Index), mapt.Key()), + } + v.setPos(e.Lbrack) + v.setType(mapt.Elem()) + return fn.emit(v) + + case *types.Basic: // => string + // Strings are not addressable. + v := &Lookup{ + X: b.expr(fn, e.X), + Index: b.expr(fn, e.Index), + } + v.setPos(e.Lbrack) + v.setType(tByte) + return fn.emit(v) + + case *types.Slice, *types.Pointer: // *array + // Addressable slice/array; use IndexAddr and Load. + return b.addr(fn, e, false).load(fn) + + default: + panic("unexpected container type in IndexExpr: " + t.String()) + } + + case *ast.CompositeLit, *ast.StarExpr: + // Addressable types (lvalues) + return b.addr(fn, e, false).load(fn) + } + + panic(fmt.Sprintf("unexpected expr: %T", e)) +} + +// stmtList emits to fn code for all statements in list. +func (b *builder) stmtList(fn *Function, list []ast.Stmt) { + for _, s := range list { + b.stmt(fn, s) + } +} + +// receiver emits to fn code for expression e in the "receiver" +// position of selection e.f (where f may be a field or a method) and +// returns the effective receiver after applying the implicit field +// selections of sel. +// +// wantAddr requests that the result is an an address. If +// !sel.Indirect(), this may require that e be built in addr() mode; it +// must thus be addressable. +// +// escaping is defined as per builder.addr(). +// +func (b *builder) receiver(fn *Function, e ast.Expr, wantAddr, escaping bool, sel *types.Selection) Value { + var v Value + if wantAddr && !sel.Indirect() && !isPointer(fn.Pkg.typeOf(e)) { + v = b.addr(fn, e, escaping).address(fn) + } else { + v = b.expr(fn, e) + } + + last := len(sel.Index()) - 1 + v = emitImplicitSelections(fn, v, sel.Index()[:last]) + if !wantAddr && isPointer(v.Type()) { + v = emitLoad(fn, v) + } + return v +} + +// setCallFunc populates the function parts of a CallCommon structure +// (Func, Method, Recv, Args[0]) based on the kind of invocation +// occurring in e. +// +func (b *builder) setCallFunc(fn *Function, e *ast.CallExpr, c *CallCommon) { + c.pos = e.Lparen + + // Is this a method call? + if selector, ok := unparen(e.Fun).(*ast.SelectorExpr); ok { + sel, ok := fn.Pkg.info.Selections[selector] + if ok && sel.Kind() == types.MethodVal { + obj := sel.Obj().(*types.Func) + recv := recvType(obj) + wantAddr := isPointer(recv) + escaping := true + v := b.receiver(fn, selector.X, wantAddr, escaping, sel) + if isInterface(recv) { + // Invoke-mode call. + c.Value = v + c.Method = obj + } else { + // "Call"-mode call. + c.Value = fn.Prog.declaredFunc(obj) + c.Args = append(c.Args, v) + } + return + } + + // sel.Kind()==MethodExpr indicates T.f() or (*T).f(): + // a statically dispatched call to the method f in the + // method-set of T or *T. T may be an interface. + // + // e.Fun would evaluate to a concrete method, interface + // wrapper function, or promotion wrapper. + // + // For now, we evaluate it in the usual way. + // + // TODO(adonovan): opt: inline expr() here, to make the + // call static and to avoid generation of wrappers. + // It's somewhat tricky as it may consume the first + // actual parameter if the call is "invoke" mode. + // + // Examples: + // type T struct{}; func (T) f() {} // "call" mode + // type T interface { f() } // "invoke" mode + // + // type S struct{ T } + // + // var s S + // S.f(s) + // (*S).f(&s) + // + // Suggested approach: + // - consume the first actual parameter expression + // and build it with b.expr(). + // - apply implicit field selections. + // - use MethodVal logic to populate fields of c. + } + + // Evaluate the function operand in the usual way. + c.Value = b.expr(fn, e.Fun) +} + +// emitCallArgs emits to f code for the actual parameters of call e to +// a (possibly built-in) function of effective type sig. +// The argument values are appended to args, which is then returned. +// +func (b *builder) emitCallArgs(fn *Function, sig *types.Signature, e *ast.CallExpr, args []Value) []Value { + // f(x, y, z...): pass slice z straight through. + if e.Ellipsis != 0 { + for i, arg := range e.Args { + v := emitConv(fn, b.expr(fn, arg), sig.Params().At(i).Type()) + args = append(args, v) + } + return args + } + + offset := len(args) // 1 if call has receiver, 0 otherwise + + // Evaluate actual parameter expressions. + // + // If this is a chained call of the form f(g()) where g has + // multiple return values (MRV), they are flattened out into + // args; a suffix of them may end up in a varargs slice. + for _, arg := range e.Args { + v := b.expr(fn, arg) + if ttuple, ok := v.Type().(*types.Tuple); ok { // MRV chain + for i, n := 0, ttuple.Len(); i < n; i++ { + args = append(args, emitExtract(fn, v, i)) + } + } else { + args = append(args, v) + } + } + + // Actual->formal assignability conversions for normal parameters. + np := sig.Params().Len() // number of normal parameters + if sig.Variadic() { + np-- + } + for i := 0; i < np; i++ { + args[offset+i] = emitConv(fn, args[offset+i], sig.Params().At(i).Type()) + } + + // Actual->formal assignability conversions for variadic parameter, + // and construction of slice. + if sig.Variadic() { + varargs := args[offset+np:] + st := sig.Params().At(np).Type().(*types.Slice) + vt := st.Elem() + if len(varargs) == 0 { + args = append(args, nilConst(st)) + } else { + // Replace a suffix of args with a slice containing it. + at := types.NewArray(vt, int64(len(varargs))) + a := emitNew(fn, at, token.NoPos) + a.setPos(e.Rparen) + a.Comment = "varargs" + for i, arg := range varargs { + iaddr := &IndexAddr{ + X: a, + Index: intConst(int64(i)), + } + iaddr.setType(types.NewPointer(vt)) + fn.emit(iaddr) + emitStore(fn, iaddr, arg, arg.Pos()) + } + s := &Slice{X: a} + s.setType(st) + args[offset+np] = fn.emit(s) + args = args[:offset+np+1] + } + } + return args +} + +// setCall emits to fn code to evaluate all the parameters of a function +// call e, and populates *c with those values. +// +func (b *builder) setCall(fn *Function, e *ast.CallExpr, c *CallCommon) { + // First deal with the f(...) part and optional receiver. + b.setCallFunc(fn, e, c) + + // Then append the other actual parameters. + sig, _ := fn.Pkg.typeOf(e.Fun).Underlying().(*types.Signature) + if sig == nil { + panic(fmt.Sprintf("no signature for call of %s", e.Fun)) + } + c.Args = b.emitCallArgs(fn, sig, e, c.Args) +} + +// assignOp emits to fn code to perform loc += incr or loc -= incr. +func (b *builder) assignOp(fn *Function, loc lvalue, incr Value, op token.Token, pos token.Pos) { + oldv := loc.load(fn) + loc.store(fn, emitArith(fn, op, oldv, emitConv(fn, incr, oldv.Type()), loc.typ(), pos)) +} + +// localValueSpec emits to fn code to define all of the vars in the +// function-local ValueSpec, spec. +// +func (b *builder) localValueSpec(fn *Function, spec *ast.ValueSpec) { + switch { + case len(spec.Values) == len(spec.Names): + // e.g. var x, y = 0, 1 + // 1:1 assignment + for i, id := range spec.Names { + if !isBlankIdent(id) { + fn.addLocalForIdent(id) + } + lval := b.addr(fn, id, false) // non-escaping + b.assign(fn, lval, spec.Values[i], true, nil) + } + + case len(spec.Values) == 0: + // e.g. var x, y int + // Locals are implicitly zero-initialized. + for _, id := range spec.Names { + if !isBlankIdent(id) { + lhs := fn.addLocalForIdent(id) + if fn.debugInfo() { + emitDebugRef(fn, id, lhs, true) + } + } + } + + default: + // e.g. var x, y = pos() + tuple := b.exprN(fn, spec.Values[0]) + for i, id := range spec.Names { + if !isBlankIdent(id) { + fn.addLocalForIdent(id) + lhs := b.addr(fn, id, false) // non-escaping + lhs.store(fn, emitExtract(fn, tuple, i)) + } + } + } +} + +// assignStmt emits code to fn for a parallel assignment of rhss to lhss. +// isDef is true if this is a short variable declaration (:=). +// +// Note the similarity with localValueSpec. +// +func (b *builder) assignStmt(fn *Function, lhss, rhss []ast.Expr, isDef bool) { + // Side effects of all LHSs and RHSs must occur in left-to-right order. + lvals := make([]lvalue, len(lhss)) + isZero := make([]bool, len(lhss)) + for i, lhs := range lhss { + var lval lvalue = blank{} + if !isBlankIdent(lhs) { + if isDef { + if obj := fn.Pkg.info.Defs[lhs.(*ast.Ident)]; obj != nil { + fn.addNamedLocal(obj) + isZero[i] = true + } + } + lval = b.addr(fn, lhs, false) // non-escaping + } + lvals[i] = lval + } + if len(lhss) == len(rhss) { + // Simple assignment: x = f() (!isDef) + // Parallel assignment: x, y = f(), g() (!isDef) + // or short var decl: x, y := f(), g() (isDef) + // + // In all cases, the RHSs may refer to the LHSs, + // so we need a storebuf. + var sb storebuf + for i := range rhss { + b.assign(fn, lvals[i], rhss[i], isZero[i], &sb) + } + sb.emit(fn) + } else { + // e.g. x, y = pos() + tuple := b.exprN(fn, rhss[0]) + emitDebugRef(fn, rhss[0], tuple, false) + for i, lval := range lvals { + lval.store(fn, emitExtract(fn, tuple, i)) + } + } +} + +// arrayLen returns the length of the array whose composite literal elements are elts. +func (b *builder) arrayLen(fn *Function, elts []ast.Expr) int64 { + var max int64 = -1 + var i int64 = -1 + for _, e := range elts { + if kv, ok := e.(*ast.KeyValueExpr); ok { + i = b.expr(fn, kv.Key).(*Const).Int64() + } else { + i++ + } + if i > max { + max = i + } + } + return max + 1 +} + +// compLit emits to fn code to initialize a composite literal e at +// address addr with type typ. +// +// Nested composite literals are recursively initialized in place +// where possible. If isZero is true, compLit assumes that addr +// holds the zero value for typ. +// +// Because the elements of a composite literal may refer to the +// variables being updated, as in the second line below, +// x := T{a: 1} +// x = T{a: x.a} +// all the reads must occur before all the writes. Thus all stores to +// loc are emitted to the storebuf sb for later execution. +// +// A CompositeLit may have pointer type only in the recursive (nested) +// case when the type name is implicit. e.g. in []*T{{}}, the inner +// literal has type *T behaves like &T{}. +// In that case, addr must hold a T, not a *T. +// +func (b *builder) compLit(fn *Function, addr Value, e *ast.CompositeLit, isZero bool, sb *storebuf) { + typ := deref(fn.Pkg.typeOf(e)) + switch t := typ.Underlying().(type) { + case *types.Struct: + if !isZero && len(e.Elts) != t.NumFields() { + // memclear + sb.store(&address{addr, e.Lbrace, nil}, + zeroValue(fn, deref(addr.Type()))) + isZero = true + } + for i, e := range e.Elts { + fieldIndex := i + pos := e.Pos() + if kv, ok := e.(*ast.KeyValueExpr); ok { + fname := kv.Key.(*ast.Ident).Name + for i, n := 0, t.NumFields(); i < n; i++ { + sf := t.Field(i) + if sf.Name() == fname { + fieldIndex = i + pos = kv.Colon + e = kv.Value + break + } + } + } + sf := t.Field(fieldIndex) + faddr := &FieldAddr{ + X: addr, + Field: fieldIndex, + } + faddr.setType(types.NewPointer(sf.Type())) + fn.emit(faddr) + b.assign(fn, &address{addr: faddr, pos: pos, expr: e}, e, isZero, sb) + } + + case *types.Array, *types.Slice: + var at *types.Array + var array Value + switch t := t.(type) { + case *types.Slice: + at = types.NewArray(t.Elem(), b.arrayLen(fn, e.Elts)) + alloc := emitNew(fn, at, e.Lbrace) + alloc.Comment = "slicelit" + array = alloc + case *types.Array: + at = t + array = addr + + if !isZero && int64(len(e.Elts)) != at.Len() { + // memclear + sb.store(&address{array, e.Lbrace, nil}, + zeroValue(fn, deref(array.Type()))) + } + } + + var idx *Const + for _, e := range e.Elts { + pos := e.Pos() + if kv, ok := e.(*ast.KeyValueExpr); ok { + idx = b.expr(fn, kv.Key).(*Const) + pos = kv.Colon + e = kv.Value + } else { + var idxval int64 + if idx != nil { + idxval = idx.Int64() + 1 + } + idx = intConst(idxval) + } + iaddr := &IndexAddr{ + X: array, + Index: idx, + } + iaddr.setType(types.NewPointer(at.Elem())) + fn.emit(iaddr) + if t != at { // slice + // backing array is unaliased => storebuf not needed. + b.assign(fn, &address{addr: iaddr, pos: pos, expr: e}, e, true, nil) + } else { + b.assign(fn, &address{addr: iaddr, pos: pos, expr: e}, e, true, sb) + } + } + + if t != at { // slice + s := &Slice{X: array} + s.setPos(e.Lbrace) + s.setType(typ) + sb.store(&address{addr: addr, pos: e.Lbrace, expr: e}, fn.emit(s)) + } + + case *types.Map: + m := &MakeMap{Reserve: intConst(int64(len(e.Elts)))} + m.setPos(e.Lbrace) + m.setType(typ) + fn.emit(m) + for _, e := range e.Elts { + e := e.(*ast.KeyValueExpr) + + // If a key expression in a map literal is itself a + // composite literal, the type may be omitted. + // For example: + // map[*struct{}]bool{{}: true} + // An &-operation may be implied: + // map[*struct{}]bool{&struct{}{}: true} + var key Value + if _, ok := unparen(e.Key).(*ast.CompositeLit); ok && isPointer(t.Key()) { + // A CompositeLit never evaluates to a pointer, + // so if the type of the location is a pointer, + // an &-operation is implied. + key = b.addr(fn, e.Key, true).address(fn) + } else { + key = b.expr(fn, e.Key) + } + + loc := element{ + m: m, + k: emitConv(fn, key, t.Key()), + t: t.Elem(), + pos: e.Colon, + } + + // We call assign() only because it takes care + // of any &-operation required in the recursive + // case, e.g., + // map[int]*struct{}{0: {}} implies &struct{}{}. + // In-place update is of course impossible, + // and no storebuf is needed. + b.assign(fn, &loc, e.Value, true, nil) + } + sb.store(&address{addr: addr, pos: e.Lbrace, expr: e}, m) + + default: + panic("unexpected CompositeLit type: " + t.String()) + } +} + +// switchStmt emits to fn code for the switch statement s, optionally +// labelled by label. +// +func (b *builder) switchStmt(fn *Function, s *ast.SwitchStmt, label *lblock) { + // We treat SwitchStmt like a sequential if-else chain. + // Multiway dispatch can be recovered later by ssautil.Switches() + // to those cases that are free of side effects. + if s.Init != nil { + b.stmt(fn, s.Init) + } + var tag Value = vTrue + if s.Tag != nil { + tag = b.expr(fn, s.Tag) + } + done := fn.newBasicBlock("switch.done") + if label != nil { + label._break = done + } + // We pull the default case (if present) down to the end. + // But each fallthrough label must point to the next + // body block in source order, so we preallocate a + // body block (fallthru) for the next case. + // Unfortunately this makes for a confusing block order. + var dfltBody *[]ast.Stmt + var dfltFallthrough *BasicBlock + var fallthru, dfltBlock *BasicBlock + ncases := len(s.Body.List) + for i, clause := range s.Body.List { + body := fallthru + if body == nil { + body = fn.newBasicBlock("switch.body") // first case only + } + + // Preallocate body block for the next case. + fallthru = done + if i+1 < ncases { + fallthru = fn.newBasicBlock("switch.body") + } + + cc := clause.(*ast.CaseClause) + if cc.List == nil { + // Default case. + dfltBody = &cc.Body + dfltFallthrough = fallthru + dfltBlock = body + continue + } + + var nextCond *BasicBlock + for _, cond := range cc.List { + nextCond = fn.newBasicBlock("switch.next") + // TODO(adonovan): opt: when tag==vTrue, we'd + // get better code if we use b.cond(cond) + // instead of BinOp(EQL, tag, b.expr(cond)) + // followed by If. Don't forget conversions + // though. + cond := emitCompare(fn, token.EQL, tag, b.expr(fn, cond), token.NoPos) + emitIf(fn, cond, body, nextCond) + fn.currentBlock = nextCond + } + fn.currentBlock = body + fn.targets = &targets{ + tail: fn.targets, + _break: done, + _fallthrough: fallthru, + } + b.stmtList(fn, cc.Body) + fn.targets = fn.targets.tail + emitJump(fn, done) + fn.currentBlock = nextCond + } + if dfltBlock != nil { + emitJump(fn, dfltBlock) + fn.currentBlock = dfltBlock + fn.targets = &targets{ + tail: fn.targets, + _break: done, + _fallthrough: dfltFallthrough, + } + b.stmtList(fn, *dfltBody) + fn.targets = fn.targets.tail + } + emitJump(fn, done) + fn.currentBlock = done +} + +// typeSwitchStmt emits to fn code for the type switch statement s, optionally +// labelled by label. +// +func (b *builder) typeSwitchStmt(fn *Function, s *ast.TypeSwitchStmt, label *lblock) { + // We treat TypeSwitchStmt like a sequential if-else chain. + // Multiway dispatch can be recovered later by ssautil.Switches(). + + // Typeswitch lowering: + // + // var x X + // switch y := x.(type) { + // case T1, T2: S1 // >1 (y := x) + // case nil: SN // nil (y := x) + // default: SD // 0 types (y := x) + // case T3: S3 // 1 type (y := x.(T3)) + // } + // + // ...s.Init... + // x := eval x + // .caseT1: + // t1, ok1 := typeswitch,ok x <T1> + // if ok1 then goto S1 else goto .caseT2 + // .caseT2: + // t2, ok2 := typeswitch,ok x <T2> + // if ok2 then goto S1 else goto .caseNil + // .S1: + // y := x + // ...S1... + // goto done + // .caseNil: + // if t2, ok2 := typeswitch,ok x <T2> + // if x == nil then goto SN else goto .caseT3 + // .SN: + // y := x + // ...SN... + // goto done + // .caseT3: + // t3, ok3 := typeswitch,ok x <T3> + // if ok3 then goto S3 else goto default + // .S3: + // y := t3 + // ...S3... + // goto done + // .default: + // y := x + // ...SD... + // goto done + // .done: + + if s.Init != nil { + b.stmt(fn, s.Init) + } + + var x Value + switch ass := s.Assign.(type) { + case *ast.ExprStmt: // x.(type) + x = b.expr(fn, unparen(ass.X).(*ast.TypeAssertExpr).X) + case *ast.AssignStmt: // y := x.(type) + x = b.expr(fn, unparen(ass.Rhs[0]).(*ast.TypeAssertExpr).X) + } + + done := fn.newBasicBlock("typeswitch.done") + if label != nil { + label._break = done + } + var default_ *ast.CaseClause + for _, clause := range s.Body.List { + cc := clause.(*ast.CaseClause) + if cc.List == nil { + default_ = cc + continue + } + body := fn.newBasicBlock("typeswitch.body") + var next *BasicBlock + var casetype types.Type + var ti Value // ti, ok := typeassert,ok x <Ti> + for _, cond := range cc.List { + next = fn.newBasicBlock("typeswitch.next") + casetype = fn.Pkg.typeOf(cond) + var condv Value + if casetype == tUntypedNil { + condv = emitCompare(fn, token.EQL, x, nilConst(x.Type()), token.NoPos) + ti = x + } else { + yok := emitTypeTest(fn, x, casetype, cc.Case) + ti = emitExtract(fn, yok, 0) + condv = emitExtract(fn, yok, 1) + } + emitIf(fn, condv, body, next) + fn.currentBlock = next + } + if len(cc.List) != 1 { + ti = x + } + fn.currentBlock = body + b.typeCaseBody(fn, cc, ti, done) + fn.currentBlock = next + } + if default_ != nil { + b.typeCaseBody(fn, default_, x, done) + } else { + emitJump(fn, done) + } + fn.currentBlock = done +} + +func (b *builder) typeCaseBody(fn *Function, cc *ast.CaseClause, x Value, done *BasicBlock) { + if obj := fn.Pkg.info.Implicits[cc]; obj != nil { + // In a switch y := x.(type), each case clause + // implicitly declares a distinct object y. + // In a single-type case, y has that type. + // In multi-type cases, 'case nil' and default, + // y has the same type as the interface operand. + emitStore(fn, fn.addNamedLocal(obj), x, obj.Pos()) + } + fn.targets = &targets{ + tail: fn.targets, + _break: done, + } + b.stmtList(fn, cc.Body) + fn.targets = fn.targets.tail + emitJump(fn, done) +} + +// selectStmt emits to fn code for the select statement s, optionally +// labelled by label. +// +func (b *builder) selectStmt(fn *Function, s *ast.SelectStmt, label *lblock) { + // A blocking select of a single case degenerates to a + // simple send or receive. + // TODO(adonovan): opt: is this optimization worth its weight? + if len(s.Body.List) == 1 { + clause := s.Body.List[0].(*ast.CommClause) + if clause.Comm != nil { + b.stmt(fn, clause.Comm) + done := fn.newBasicBlock("select.done") + if label != nil { + label._break = done + } + fn.targets = &targets{ + tail: fn.targets, + _break: done, + } + b.stmtList(fn, clause.Body) + fn.targets = fn.targets.tail + emitJump(fn, done) + fn.currentBlock = done + return + } + } + + // First evaluate all channels in all cases, and find + // the directions of each state. + var states []*SelectState + blocking := true + debugInfo := fn.debugInfo() + for _, clause := range s.Body.List { + var st *SelectState + switch comm := clause.(*ast.CommClause).Comm.(type) { + case nil: // default case + blocking = false + continue + + case *ast.SendStmt: // ch<- i + ch := b.expr(fn, comm.Chan) + st = &SelectState{ + Dir: types.SendOnly, + Chan: ch, + Send: emitConv(fn, b.expr(fn, comm.Value), + ch.Type().Underlying().(*types.Chan).Elem()), + Pos: comm.Arrow, + } + if debugInfo { + st.DebugNode = comm + } + + case *ast.AssignStmt: // x := <-ch + recv := unparen(comm.Rhs[0]).(*ast.UnaryExpr) + st = &SelectState{ + Dir: types.RecvOnly, + Chan: b.expr(fn, recv.X), + Pos: recv.OpPos, + } + if debugInfo { + st.DebugNode = recv + } + + case *ast.ExprStmt: // <-ch + recv := unparen(comm.X).(*ast.UnaryExpr) + st = &SelectState{ + Dir: types.RecvOnly, + Chan: b.expr(fn, recv.X), + Pos: recv.OpPos, + } + if debugInfo { + st.DebugNode = recv + } + } + states = append(states, st) + } + + // We dispatch on the (fair) result of Select using a + // sequential if-else chain, in effect: + // + // idx, recvOk, r0...r_n-1 := select(...) + // if idx == 0 { // receive on channel 0 (first receive => r0) + // x, ok := r0, recvOk + // ...state0... + // } else if v == 1 { // send on channel 1 + // ...state1... + // } else { + // ...default... + // } + sel := &Select{ + States: states, + Blocking: blocking, + } + sel.setPos(s.Select) + var vars []*types.Var + vars = append(vars, varIndex, varOk) + for _, st := range states { + if st.Dir == types.RecvOnly { + tElem := st.Chan.Type().Underlying().(*types.Chan).Elem() + vars = append(vars, anonVar(tElem)) + } + } + sel.setType(types.NewTuple(vars...)) + + fn.emit(sel) + idx := emitExtract(fn, sel, 0) + + done := fn.newBasicBlock("select.done") + if label != nil { + label._break = done + } + + var defaultBody *[]ast.Stmt + state := 0 + r := 2 // index in 'sel' tuple of value; increments if st.Dir==RECV + for _, cc := range s.Body.List { + clause := cc.(*ast.CommClause) + if clause.Comm == nil { + defaultBody = &clause.Body + continue + } + body := fn.newBasicBlock("select.body") + next := fn.newBasicBlock("select.next") + emitIf(fn, emitCompare(fn, token.EQL, idx, intConst(int64(state)), token.NoPos), body, next) + fn.currentBlock = body + fn.targets = &targets{ + tail: fn.targets, + _break: done, + } + switch comm := clause.Comm.(type) { + case *ast.ExprStmt: // <-ch + if debugInfo { + v := emitExtract(fn, sel, r) + emitDebugRef(fn, states[state].DebugNode.(ast.Expr), v, false) + } + r++ + + case *ast.AssignStmt: // x := <-states[state].Chan + if comm.Tok == token.DEFINE { + fn.addLocalForIdent(comm.Lhs[0].(*ast.Ident)) + } + x := b.addr(fn, comm.Lhs[0], false) // non-escaping + v := emitExtract(fn, sel, r) + if debugInfo { + emitDebugRef(fn, states[state].DebugNode.(ast.Expr), v, false) + } + x.store(fn, v) + + if len(comm.Lhs) == 2 { // x, ok := ... + if comm.Tok == token.DEFINE { + fn.addLocalForIdent(comm.Lhs[1].(*ast.Ident)) + } + ok := b.addr(fn, comm.Lhs[1], false) // non-escaping + ok.store(fn, emitExtract(fn, sel, 1)) + } + r++ + } + b.stmtList(fn, clause.Body) + fn.targets = fn.targets.tail + emitJump(fn, done) + fn.currentBlock = next + state++ + } + if defaultBody != nil { + fn.targets = &targets{ + tail: fn.targets, + _break: done, + } + b.stmtList(fn, *defaultBody) + fn.targets = fn.targets.tail + } else { + // A blocking select must match some case. + // (This should really be a runtime.errorString, not a string.) + fn.emit(&Panic{ + X: emitConv(fn, stringConst("blocking select matched no case"), tEface), + }) + fn.currentBlock = fn.newBasicBlock("unreachable") + } + emitJump(fn, done) + fn.currentBlock = done +} + +// forStmt emits to fn code for the for statement s, optionally +// labelled by label. +// +func (b *builder) forStmt(fn *Function, s *ast.ForStmt, label *lblock) { + // ...init... + // jump loop + // loop: + // if cond goto body else done + // body: + // ...body... + // jump post + // post: (target of continue) + // ...post... + // jump loop + // done: (target of break) + if s.Init != nil { + b.stmt(fn, s.Init) + } + body := fn.newBasicBlock("for.body") + done := fn.newBasicBlock("for.done") // target of 'break' + loop := body // target of back-edge + if s.Cond != nil { + loop = fn.newBasicBlock("for.loop") + } + cont := loop // target of 'continue' + if s.Post != nil { + cont = fn.newBasicBlock("for.post") + } + if label != nil { + label._break = done + label._continue = cont + } + emitJump(fn, loop) + fn.currentBlock = loop + if loop != body { + b.cond(fn, s.Cond, body, done) + fn.currentBlock = body + } + fn.targets = &targets{ + tail: fn.targets, + _break: done, + _continue: cont, + } + b.stmt(fn, s.Body) + fn.targets = fn.targets.tail + emitJump(fn, cont) + + if s.Post != nil { + fn.currentBlock = cont + b.stmt(fn, s.Post) + emitJump(fn, loop) // back-edge + } + fn.currentBlock = done +} + +// rangeIndexed emits to fn the header for an integer-indexed loop +// over array, *array or slice value x. +// The v result is defined only if tv is non-nil. +// forPos is the position of the "for" token. +// +func (b *builder) rangeIndexed(fn *Function, x Value, tv types.Type, pos token.Pos) (k, v Value, loop, done *BasicBlock) { + // + // length = len(x) + // index = -1 + // loop: (target of continue) + // index++ + // if index < length goto body else done + // body: + // k = index + // v = x[index] + // ...body... + // jump loop + // done: (target of break) + + // Determine number of iterations. + var length Value + if arr, ok := deref(x.Type()).Underlying().(*types.Array); ok { + // For array or *array, the number of iterations is + // known statically thanks to the type. We avoid a + // data dependence upon x, permitting later dead-code + // elimination if x is pure, static unrolling, etc. + // Ranging over a nil *array may have >0 iterations. + // We still generate code for x, in case it has effects. + length = intConst(arr.Len()) + } else { + // length = len(x). + var c Call + c.Call.Value = makeLen(x.Type()) + c.Call.Args = []Value{x} + c.setType(tInt) + length = fn.emit(&c) + } + + index := fn.addLocal(tInt, token.NoPos) + emitStore(fn, index, intConst(-1), pos) + + loop = fn.newBasicBlock("rangeindex.loop") + emitJump(fn, loop) + fn.currentBlock = loop + + incr := &BinOp{ + Op: token.ADD, + X: emitLoad(fn, index), + Y: vOne, + } + incr.setType(tInt) + emitStore(fn, index, fn.emit(incr), pos) + + body := fn.newBasicBlock("rangeindex.body") + done = fn.newBasicBlock("rangeindex.done") + emitIf(fn, emitCompare(fn, token.LSS, incr, length, token.NoPos), body, done) + fn.currentBlock = body + + k = emitLoad(fn, index) + if tv != nil { + switch t := x.Type().Underlying().(type) { + case *types.Array: + instr := &Index{ + X: x, + Index: k, + } + instr.setType(t.Elem()) + v = fn.emit(instr) + + case *types.Pointer: // *array + instr := &IndexAddr{ + X: x, + Index: k, + } + instr.setType(types.NewPointer(t.Elem().Underlying().(*types.Array).Elem())) + v = emitLoad(fn, fn.emit(instr)) + + case *types.Slice: + instr := &IndexAddr{ + X: x, + Index: k, + } + instr.setType(types.NewPointer(t.Elem())) + v = emitLoad(fn, fn.emit(instr)) + + default: + panic("rangeIndexed x:" + t.String()) + } + } + return +} + +// rangeIter emits to fn the header for a loop using +// Range/Next/Extract to iterate over map or string value x. +// tk and tv are the types of the key/value results k and v, or nil +// if the respective component is not wanted. +// +func (b *builder) rangeIter(fn *Function, x Value, tk, tv types.Type, pos token.Pos) (k, v Value, loop, done *BasicBlock) { + // + // it = range x + // loop: (target of continue) + // okv = next it (ok, key, value) + // ok = extract okv #0 + // if ok goto body else done + // body: + // k = extract okv #1 + // v = extract okv #2 + // ...body... + // jump loop + // done: (target of break) + // + + if tk == nil { + tk = tInvalid + } + if tv == nil { + tv = tInvalid + } + + rng := &Range{X: x} + rng.setPos(pos) + rng.setType(tRangeIter) + it := fn.emit(rng) + + loop = fn.newBasicBlock("rangeiter.loop") + emitJump(fn, loop) + fn.currentBlock = loop + + _, isString := x.Type().Underlying().(*types.Basic) + + okv := &Next{ + Iter: it, + IsString: isString, + } + okv.setType(types.NewTuple( + varOk, + newVar("k", tk), + newVar("v", tv), + )) + fn.emit(okv) + + body := fn.newBasicBlock("rangeiter.body") + done = fn.newBasicBlock("rangeiter.done") + emitIf(fn, emitExtract(fn, okv, 0), body, done) + fn.currentBlock = body + + if tk != tInvalid { + k = emitExtract(fn, okv, 1) + } + if tv != tInvalid { + v = emitExtract(fn, okv, 2) + } + return +} + +// rangeChan emits to fn the header for a loop that receives from +// channel x until it fails. +// tk is the channel's element type, or nil if the k result is +// not wanted +// pos is the position of the '=' or ':=' token. +// +func (b *builder) rangeChan(fn *Function, x Value, tk types.Type, pos token.Pos) (k Value, loop, done *BasicBlock) { + // + // loop: (target of continue) + // ko = <-x (key, ok) + // ok = extract ko #1 + // if ok goto body else done + // body: + // k = extract ko #0 + // ... + // goto loop + // done: (target of break) + + loop = fn.newBasicBlock("rangechan.loop") + emitJump(fn, loop) + fn.currentBlock = loop + recv := &UnOp{ + Op: token.ARROW, + X: x, + CommaOk: true, + } + recv.setPos(pos) + recv.setType(types.NewTuple( + newVar("k", x.Type().Underlying().(*types.Chan).Elem()), + varOk, + )) + ko := fn.emit(recv) + body := fn.newBasicBlock("rangechan.body") + done = fn.newBasicBlock("rangechan.done") + emitIf(fn, emitExtract(fn, ko, 1), body, done) + fn.currentBlock = body + if tk != nil { + k = emitExtract(fn, ko, 0) + } + return +} + +// rangeStmt emits to fn code for the range statement s, optionally +// labelled by label. +// +func (b *builder) rangeStmt(fn *Function, s *ast.RangeStmt, label *lblock) { + var tk, tv types.Type + if s.Key != nil && !isBlankIdent(s.Key) { + tk = fn.Pkg.typeOf(s.Key) + } + if s.Value != nil && !isBlankIdent(s.Value) { + tv = fn.Pkg.typeOf(s.Value) + } + + // If iteration variables are defined (:=), this + // occurs once outside the loop. + // + // Unlike a short variable declaration, a RangeStmt + // using := never redeclares an existing variable; it + // always creates a new one. + if s.Tok == token.DEFINE { + if tk != nil { + fn.addLocalForIdent(s.Key.(*ast.Ident)) + } + if tv != nil { + fn.addLocalForIdent(s.Value.(*ast.Ident)) + } + } + + x := b.expr(fn, s.X) + + var k, v Value + var loop, done *BasicBlock + switch rt := x.Type().Underlying().(type) { + case *types.Slice, *types.Array, *types.Pointer: // *array + k, v, loop, done = b.rangeIndexed(fn, x, tv, s.For) + + case *types.Chan: + k, loop, done = b.rangeChan(fn, x, tk, s.For) + + case *types.Map, *types.Basic: // string + k, v, loop, done = b.rangeIter(fn, x, tk, tv, s.For) + + default: + panic("Cannot range over: " + rt.String()) + } + + // Evaluate both LHS expressions before we update either. + var kl, vl lvalue + if tk != nil { + kl = b.addr(fn, s.Key, false) // non-escaping + } + if tv != nil { + vl = b.addr(fn, s.Value, false) // non-escaping + } + if tk != nil { + kl.store(fn, k) + } + if tv != nil { + vl.store(fn, v) + } + + if label != nil { + label._break = done + label._continue = loop + } + + fn.targets = &targets{ + tail: fn.targets, + _break: done, + _continue: loop, + } + b.stmt(fn, s.Body) + fn.targets = fn.targets.tail + emitJump(fn, loop) // back-edge + fn.currentBlock = done +} + +// stmt lowers statement s to SSA form, emitting code to fn. +func (b *builder) stmt(fn *Function, _s ast.Stmt) { + // The label of the current statement. If non-nil, its _goto + // target is always set; its _break and _continue are set only + // within the body of switch/typeswitch/select/for/range. + // It is effectively an additional default-nil parameter of stmt(). + var label *lblock +start: + switch s := _s.(type) { + case *ast.EmptyStmt: + // ignore. (Usually removed by gofmt.) + + case *ast.DeclStmt: // Con, Var or Typ + d := s.Decl.(*ast.GenDecl) + if d.Tok == token.VAR { + for _, spec := range d.Specs { + if vs, ok := spec.(*ast.ValueSpec); ok { + b.localValueSpec(fn, vs) + } + } + } + + case *ast.LabeledStmt: + label = fn.labelledBlock(s.Label) + emitJump(fn, label._goto) + fn.currentBlock = label._goto + _s = s.Stmt + goto start // effectively: tailcall stmt(fn, s.Stmt, label) + + case *ast.ExprStmt: + b.expr(fn, s.X) + + case *ast.SendStmt: + fn.emit(&Send{ + Chan: b.expr(fn, s.Chan), + X: emitConv(fn, b.expr(fn, s.Value), + fn.Pkg.typeOf(s.Chan).Underlying().(*types.Chan).Elem()), + pos: s.Arrow, + }) + + case *ast.IncDecStmt: + op := token.ADD + if s.Tok == token.DEC { + op = token.SUB + } + loc := b.addr(fn, s.X, false) + b.assignOp(fn, loc, NewConst(exact.MakeInt64(1), loc.typ()), op, s.Pos()) + + case *ast.AssignStmt: + switch s.Tok { + case token.ASSIGN, token.DEFINE: + b.assignStmt(fn, s.Lhs, s.Rhs, s.Tok == token.DEFINE) + + default: // +=, etc. + op := s.Tok + token.ADD - token.ADD_ASSIGN + b.assignOp(fn, b.addr(fn, s.Lhs[0], false), b.expr(fn, s.Rhs[0]), op, s.Pos()) + } + + case *ast.GoStmt: + // The "intrinsics" new/make/len/cap are forbidden here. + // panic is treated like an ordinary function call. + v := Go{pos: s.Go} + b.setCall(fn, s.Call, &v.Call) + fn.emit(&v) + + case *ast.DeferStmt: + // The "intrinsics" new/make/len/cap are forbidden here. + // panic is treated like an ordinary function call. + v := Defer{pos: s.Defer} + b.setCall(fn, s.Call, &v.Call) + fn.emit(&v) + + // A deferred call can cause recovery from panic, + // and control resumes at the Recover block. + createRecoverBlock(fn) + + case *ast.ReturnStmt: + var results []Value + if len(s.Results) == 1 && fn.Signature.Results().Len() > 1 { + // Return of one expression in a multi-valued function. + tuple := b.exprN(fn, s.Results[0]) + ttuple := tuple.Type().(*types.Tuple) + for i, n := 0, ttuple.Len(); i < n; i++ { + results = append(results, + emitConv(fn, emitExtract(fn, tuple, i), + fn.Signature.Results().At(i).Type())) + } + } else { + // 1:1 return, or no-arg return in non-void function. + for i, r := range s.Results { + v := emitConv(fn, b.expr(fn, r), fn.Signature.Results().At(i).Type()) + results = append(results, v) + } + } + if fn.namedResults != nil { + // Function has named result parameters (NRPs). + // Perform parallel assignment of return operands to NRPs. + for i, r := range results { + emitStore(fn, fn.namedResults[i], r, s.Return) + } + } + // Run function calls deferred in this + // function when explicitly returning from it. + fn.emit(new(RunDefers)) + if fn.namedResults != nil { + // Reload NRPs to form the result tuple. + results = results[:0] + for _, r := range fn.namedResults { + results = append(results, emitLoad(fn, r)) + } + } + fn.emit(&Return{Results: results, pos: s.Return}) + fn.currentBlock = fn.newBasicBlock("unreachable") + + case *ast.BranchStmt: + var block *BasicBlock + switch s.Tok { + case token.BREAK: + if s.Label != nil { + block = fn.labelledBlock(s.Label)._break + } else { + for t := fn.targets; t != nil && block == nil; t = t.tail { + block = t._break + } + } + + case token.CONTINUE: + if s.Label != nil { + block = fn.labelledBlock(s.Label)._continue + } else { + for t := fn.targets; t != nil && block == nil; t = t.tail { + block = t._continue + } + } + + case token.FALLTHROUGH: + for t := fn.targets; t != nil && block == nil; t = t.tail { + block = t._fallthrough + } + + case token.GOTO: + block = fn.labelledBlock(s.Label)._goto + } + emitJump(fn, block) + fn.currentBlock = fn.newBasicBlock("unreachable") + + case *ast.BlockStmt: + b.stmtList(fn, s.List) + + case *ast.IfStmt: + if s.Init != nil { + b.stmt(fn, s.Init) + } + then := fn.newBasicBlock("if.then") + done := fn.newBasicBlock("if.done") + els := done + if s.Else != nil { + els = fn.newBasicBlock("if.else") + } + b.cond(fn, s.Cond, then, els) + fn.currentBlock = then + b.stmt(fn, s.Body) + emitJump(fn, done) + + if s.Else != nil { + fn.currentBlock = els + b.stmt(fn, s.Else) + emitJump(fn, done) + } + + fn.currentBlock = done + + case *ast.SwitchStmt: + b.switchStmt(fn, s, label) + + case *ast.TypeSwitchStmt: + b.typeSwitchStmt(fn, s, label) + + case *ast.SelectStmt: + b.selectStmt(fn, s, label) + + case *ast.ForStmt: + b.forStmt(fn, s, label) + + case *ast.RangeStmt: + b.rangeStmt(fn, s, label) + + default: + panic(fmt.Sprintf("unexpected statement kind: %T", s)) + } +} + +// buildFunction builds SSA code for the body of function fn. Idempotent. +func (b *builder) buildFunction(fn *Function) { + if fn.Blocks != nil { + return // building already started + } + + var recvField *ast.FieldList + var body *ast.BlockStmt + var functype *ast.FuncType + switch n := fn.syntax.(type) { + case nil: + return // not a Go source function. (Synthetic, or from object file.) + case *ast.FuncDecl: + functype = n.Type + recvField = n.Recv + body = n.Body + case *ast.FuncLit: + functype = n.Type + body = n.Body + default: + panic(n) + } + + if body == nil { + // External function. + if fn.Params == nil { + // This condition ensures we add a non-empty + // params list once only, but we may attempt + // the degenerate empty case repeatedly. + // TODO(adonovan): opt: don't do that. + + // We set Function.Params even though there is no body + // code to reference them. This simplifies clients. + if recv := fn.Signature.Recv(); recv != nil { + fn.addParamObj(recv) + } + params := fn.Signature.Params() + for i, n := 0, params.Len(); i < n; i++ { + fn.addParamObj(params.At(i)) + } + } + return + } + if fn.Prog.mode&LogSource != 0 { + defer logStack("build function %s @ %s", fn, fn.Prog.Fset.Position(fn.pos))() + } + fn.startBody() + fn.createSyntacticParams(recvField, functype) + b.stmt(fn, body) + if cb := fn.currentBlock; cb != nil && (cb == fn.Blocks[0] || cb == fn.Recover || cb.Preds != nil) { + // Control fell off the end of the function's body block. + // + // Block optimizations eliminate the current block, if + // unreachable. It is a builder invariant that + // if this no-arg return is ill-typed for + // fn.Signature.Results, this block must be + // unreachable. The sanity checker checks this. + fn.emit(new(RunDefers)) + fn.emit(new(Return)) + } + fn.finishBody() +} + +// buildFuncDecl builds SSA code for the function or method declared +// by decl in package pkg. +// +func (b *builder) buildFuncDecl(pkg *Package, decl *ast.FuncDecl) { + id := decl.Name + if isBlankIdent(id) { + return // discard + } + fn := pkg.values[pkg.info.Defs[id]].(*Function) + if decl.Recv == nil && id.Name == "init" { + var v Call + v.Call.Value = fn + v.setType(types.NewTuple()) + pkg.init.emit(&v) + } + b.buildFunction(fn) +} + +// Build calls Package.Build for each package in prog. +// Building occurs in parallel unless the BuildSerially mode flag was set. +// +// Build is intended for whole-program analysis; a typical compiler +// need only build a single package. +// +// Build is idempotent and thread-safe. +// +func (prog *Program) Build() { + var wg sync.WaitGroup + for _, p := range prog.packages { + if prog.mode&BuildSerially != 0 { + p.Build() + } else { + wg.Add(1) + go func(p *Package) { + p.Build() + wg.Done() + }(p) + } + } + wg.Wait() +} + +// Build builds SSA code for all functions and vars in package p. +// +// Precondition: CreatePackage must have been called for all of p's +// direct imports (and hence its direct imports must have been +// error-free). +// +// Build is idempotent and thread-safe. +// +func (p *Package) Build() { p.buildOnce.Do(p.build) } + +func (p *Package) build() { + if p.info == nil { + return // synthetic package, e.g. "testmain" + } + if p.files == nil { + p.info = nil + return // package loaded from export data + } + + // Ensure we have runtime type info for all exported members. + // TODO(adonovan): ideally belongs in memberFromObject, but + // that would require package creation in topological order. + for name, mem := range p.Members { + if ast.IsExported(name) { + p.Prog.needMethodsOf(mem.Type()) + } + } + if p.Prog.mode&LogSource != 0 { + defer logStack("build %s", p)() + } + init := p.init + init.startBody() + + var done *BasicBlock + + if p.Prog.mode&BareInits == 0 { + // Make init() skip if package is already initialized. + initguard := p.Var("init$guard") + doinit := init.newBasicBlock("init.start") + done = init.newBasicBlock("init.done") + emitIf(init, emitLoad(init, initguard), done, doinit) + init.currentBlock = doinit + emitStore(init, initguard, vTrue, token.NoPos) + + // Call the init() function of each package we import. + for _, pkg := range p.Pkg.Imports() { + prereq := p.Prog.packages[pkg] + if prereq == nil { + panic(fmt.Sprintf("Package(%q).Build(): unsatisfied import: Program.CreatePackage(%q) was not called", p.Pkg.Path(), pkg.Path())) + } + var v Call + v.Call.Value = prereq.init + v.Call.pos = init.pos + v.setType(types.NewTuple()) + init.emit(&v) + } + } + + var b builder + + // Initialize package-level vars in correct order. + for _, varinit := range p.info.InitOrder { + if init.Prog.mode&LogSource != 0 { + fmt.Fprintf(os.Stderr, "build global initializer %v @ %s\n", + varinit.Lhs, p.Prog.Fset.Position(varinit.Rhs.Pos())) + } + if len(varinit.Lhs) == 1 { + // 1:1 initialization: var x, y = a(), b() + var lval lvalue + if v := varinit.Lhs[0]; v.Name() != "_" { + lval = &address{addr: p.values[v].(*Global), pos: v.Pos()} + } else { + lval = blank{} + } + b.assign(init, lval, varinit.Rhs, true, nil) + } else { + // n:1 initialization: var x, y := f() + tuple := b.exprN(init, varinit.Rhs) + for i, v := range varinit.Lhs { + if v.Name() == "_" { + continue + } + emitStore(init, p.values[v].(*Global), emitExtract(init, tuple, i), v.Pos()) + } + } + } + + // Build all package-level functions, init functions + // and methods, including unreachable/blank ones. + // We build them in source order, but it's not significant. + for _, file := range p.files { + for _, decl := range file.Decls { + if decl, ok := decl.(*ast.FuncDecl); ok { + b.buildFuncDecl(p, decl) + } + } + } + + // Finish up init(). + if p.Prog.mode&BareInits == 0 { + emitJump(init, done) + init.currentBlock = done + } + init.emit(new(Return)) + init.finishBody() + + p.info = nil // We no longer need ASTs or go/types deductions. + + if p.Prog.mode&SanityCheckFunctions != 0 { + sanityCheckPackage(p) + } +} + +// Like ObjectOf, but panics instead of returning nil. +// Only valid during p's create and build phases. +func (p *Package) objectOf(id *ast.Ident) types.Object { + if o := p.info.ObjectOf(id); o != nil { + return o + } + panic(fmt.Sprintf("no types.Object for ast.Ident %s @ %s", + id.Name, p.Prog.Fset.Position(id.Pos()))) +} + +// Like TypeOf, but panics instead of returning nil. +// Only valid during p's create and build phases. +func (p *Package) typeOf(e ast.Expr) types.Type { + if T := p.info.TypeOf(e); T != nil { + return T + } + panic(fmt.Sprintf("no type for %T @ %s", + e, p.Prog.Fset.Position(e.Pos()))) +} diff --git a/vendor/honnef.co/go/tools/ssa/const.go b/vendor/honnef.co/go/tools/ssa/const.go new file mode 100644 index 0000000..3606e0f --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/const.go @@ -0,0 +1,171 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.6 + +package ssa + +// This file defines the Const SSA value type. + +import ( + "fmt" + exact "go/constant" + "go/token" + "go/types" + "strconv" +) + +// NewConst returns a new constant of the specified value and type. +// val must be valid according to the specification of Const.Value. +// +func NewConst(val exact.Value, typ types.Type) *Const { + return &Const{typ, val} +} + +// intConst returns an 'int' constant that evaluates to i. +// (i is an int64 in case the host is narrower than the target.) +func intConst(i int64) *Const { + return NewConst(exact.MakeInt64(i), tInt) +} + +// nilConst returns a nil constant of the specified type, which may +// be any reference type, including interfaces. +// +func nilConst(typ types.Type) *Const { + return NewConst(nil, typ) +} + +// stringConst returns a 'string' constant that evaluates to s. +func stringConst(s string) *Const { + return NewConst(exact.MakeString(s), tString) +} + +// zeroConst returns a new "zero" constant of the specified type, +// which must not be an array or struct type: the zero values of +// aggregates are well-defined but cannot be represented by Const. +// +func zeroConst(t types.Type) *Const { + switch t := t.(type) { + case *types.Basic: + switch { + case t.Info()&types.IsBoolean != 0: + return NewConst(exact.MakeBool(false), t) + case t.Info()&types.IsNumeric != 0: + return NewConst(exact.MakeInt64(0), t) + case t.Info()&types.IsString != 0: + return NewConst(exact.MakeString(""), t) + case t.Kind() == types.UnsafePointer: + fallthrough + case t.Kind() == types.UntypedNil: + return nilConst(t) + default: + panic(fmt.Sprint("zeroConst for unexpected type:", t)) + } + case *types.Pointer, *types.Slice, *types.Interface, *types.Chan, *types.Map, *types.Signature: + return nilConst(t) + case *types.Named: + return NewConst(zeroConst(t.Underlying()).Value, t) + case *types.Array, *types.Struct, *types.Tuple: + panic(fmt.Sprint("zeroConst applied to aggregate:", t)) + } + panic(fmt.Sprint("zeroConst: unexpected ", t)) +} + +func (c *Const) RelString(from *types.Package) string { + var s string + if c.Value == nil { + s = "nil" + } else if c.Value.Kind() == exact.String { + s = exact.StringVal(c.Value) + const max = 20 + // TODO(adonovan): don't cut a rune in half. + if len(s) > max { + s = s[:max-3] + "..." // abbreviate + } + s = strconv.Quote(s) + } else { + s = c.Value.String() + } + return s + ":" + relType(c.Type(), from) +} + +func (c *Const) Name() string { + return c.RelString(nil) +} + +func (c *Const) String() string { + return c.Name() +} + +func (c *Const) Type() types.Type { + return c.typ +} + +func (c *Const) Referrers() *[]Instruction { + return nil +} + +func (c *Const) Parent() *Function { return nil } + +func (c *Const) Pos() token.Pos { + return token.NoPos +} + +// IsNil returns true if this constant represents a typed or untyped nil value. +func (c *Const) IsNil() bool { + return c.Value == nil +} + +// TODO(adonovan): move everything below into honnef.co/go/tools/ssa/interp. + +// Int64 returns the numeric value of this constant truncated to fit +// a signed 64-bit integer. +// +func (c *Const) Int64() int64 { + switch x := exact.ToInt(c.Value); x.Kind() { + case exact.Int: + if i, ok := exact.Int64Val(x); ok { + return i + } + return 0 + case exact.Float: + f, _ := exact.Float64Val(x) + return int64(f) + } + panic(fmt.Sprintf("unexpected constant value: %T", c.Value)) +} + +// Uint64 returns the numeric value of this constant truncated to fit +// an unsigned 64-bit integer. +// +func (c *Const) Uint64() uint64 { + switch x := exact.ToInt(c.Value); x.Kind() { + case exact.Int: + if u, ok := exact.Uint64Val(x); ok { + return u + } + return 0 + case exact.Float: + f, _ := exact.Float64Val(x) + return uint64(f) + } + panic(fmt.Sprintf("unexpected constant value: %T", c.Value)) +} + +// Float64 returns the numeric value of this constant truncated to fit +// a float64. +// +func (c *Const) Float64() float64 { + f, _ := exact.Float64Val(c.Value) + return f +} + +// Complex128 returns the complex value of this constant truncated to +// fit a complex128. +// +func (c *Const) Complex128() complex128 { + re, _ := exact.Float64Val(exact.Real(c.Value)) + im, _ := exact.Float64Val(exact.Imag(c.Value)) + return complex(re, im) +} diff --git a/vendor/honnef.co/go/tools/ssa/const15.go b/vendor/honnef.co/go/tools/ssa/const15.go new file mode 100644 index 0000000..49b5333 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/const15.go @@ -0,0 +1,171 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5,!go1.6 + +package ssa + +// This file defines the Const SSA value type. + +import ( + "fmt" + exact "go/constant" + "go/token" + "go/types" + "strconv" +) + +// NewConst returns a new constant of the specified value and type. +// val must be valid according to the specification of Const.Value. +// +func NewConst(val exact.Value, typ types.Type) *Const { + return &Const{typ, val} +} + +// intConst returns an 'int' constant that evaluates to i. +// (i is an int64 in case the host is narrower than the target.) +func intConst(i int64) *Const { + return NewConst(exact.MakeInt64(i), tInt) +} + +// nilConst returns a nil constant of the specified type, which may +// be any reference type, including interfaces. +// +func nilConst(typ types.Type) *Const { + return NewConst(nil, typ) +} + +// stringConst returns a 'string' constant that evaluates to s. +func stringConst(s string) *Const { + return NewConst(exact.MakeString(s), tString) +} + +// zeroConst returns a new "zero" constant of the specified type, +// which must not be an array or struct type: the zero values of +// aggregates are well-defined but cannot be represented by Const. +// +func zeroConst(t types.Type) *Const { + switch t := t.(type) { + case *types.Basic: + switch { + case t.Info()&types.IsBoolean != 0: + return NewConst(exact.MakeBool(false), t) + case t.Info()&types.IsNumeric != 0: + return NewConst(exact.MakeInt64(0), t) + case t.Info()&types.IsString != 0: + return NewConst(exact.MakeString(""), t) + case t.Kind() == types.UnsafePointer: + fallthrough + case t.Kind() == types.UntypedNil: + return nilConst(t) + default: + panic(fmt.Sprint("zeroConst for unexpected type:", t)) + } + case *types.Pointer, *types.Slice, *types.Interface, *types.Chan, *types.Map, *types.Signature: + return nilConst(t) + case *types.Named: + return NewConst(zeroConst(t.Underlying()).Value, t) + case *types.Array, *types.Struct, *types.Tuple: + panic(fmt.Sprint("zeroConst applied to aggregate:", t)) + } + panic(fmt.Sprint("zeroConst: unexpected ", t)) +} + +func (c *Const) RelString(from *types.Package) string { + var s string + if c.Value == nil { + s = "nil" + } else if c.Value.Kind() == exact.String { + s = exact.StringVal(c.Value) + const max = 20 + // TODO(adonovan): don't cut a rune in half. + if len(s) > max { + s = s[:max-3] + "..." // abbreviate + } + s = strconv.Quote(s) + } else { + s = c.Value.String() + } + return s + ":" + relType(c.Type(), from) +} + +func (c *Const) Name() string { + return c.RelString(nil) +} + +func (c *Const) String() string { + return c.Name() +} + +func (c *Const) Type() types.Type { + return c.typ +} + +func (c *Const) Referrers() *[]Instruction { + return nil +} + +func (c *Const) Parent() *Function { return nil } + +func (c *Const) Pos() token.Pos { + return token.NoPos +} + +// IsNil returns true if this constant represents a typed or untyped nil value. +func (c *Const) IsNil() bool { + return c.Value == nil +} + +// TODO(adonovan): move everything below into honnef.co/go/tools/ssa/interp. + +// Int64 returns the numeric value of this constant truncated to fit +// a signed 64-bit integer. +// +func (c *Const) Int64() int64 { + switch x := c.Value; x.Kind() { + case exact.Int: + if i, ok := exact.Int64Val(x); ok { + return i + } + return 0 + case exact.Float: + f, _ := exact.Float64Val(x) + return int64(f) + } + panic(fmt.Sprintf("unexpected constant value: %T", c.Value)) +} + +// Uint64 returns the numeric value of this constant truncated to fit +// an unsigned 64-bit integer. +// +func (c *Const) Uint64() uint64 { + switch x := c.Value; x.Kind() { + case exact.Int: + if u, ok := exact.Uint64Val(x); ok { + return u + } + return 0 + case exact.Float: + f, _ := exact.Float64Val(x) + return uint64(f) + } + panic(fmt.Sprintf("unexpected constant value: %T", c.Value)) +} + +// Float64 returns the numeric value of this constant truncated to fit +// a float64. +// +func (c *Const) Float64() float64 { + f, _ := exact.Float64Val(c.Value) + return f +} + +// Complex128 returns the complex value of this constant truncated to +// fit a complex128. +// +func (c *Const) Complex128() complex128 { + re, _ := exact.Float64Val(exact.Real(c.Value)) + im, _ := exact.Float64Val(exact.Imag(c.Value)) + return complex(re, im) +} diff --git a/vendor/honnef.co/go/tools/ssa/create.go b/vendor/honnef.co/go/tools/ssa/create.go new file mode 100644 index 0000000..69ac12b --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/create.go @@ -0,0 +1,263 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssa + +// This file implements the CREATE phase of SSA construction. +// See builder.go for explanation. + +import ( + "fmt" + "go/ast" + "go/token" + "go/types" + "os" + "sync" + + "golang.org/x/tools/go/types/typeutil" +) + +// NewProgram returns a new SSA Program. +// +// mode controls diagnostics and checking during SSA construction. +// +func NewProgram(fset *token.FileSet, mode BuilderMode) *Program { + prog := &Program{ + Fset: fset, + imported: make(map[string]*Package), + packages: make(map[*types.Package]*Package), + thunks: make(map[selectionKey]*Function), + bounds: make(map[*types.Func]*Function), + mode: mode, + } + + h := typeutil.MakeHasher() // protected by methodsMu, in effect + prog.methodSets.SetHasher(h) + prog.canon.SetHasher(h) + + return prog +} + +// memberFromObject populates package pkg with a member for the +// typechecker object obj. +// +// For objects from Go source code, syntax is the associated syntax +// tree (for funcs and vars only); it will be used during the build +// phase. +// +func memberFromObject(pkg *Package, obj types.Object, syntax ast.Node) { + name := obj.Name() + switch obj := obj.(type) { + case *types.Builtin: + if pkg.Pkg != types.Unsafe { + panic("unexpected builtin object: " + obj.String()) + } + + case *types.TypeName: + pkg.Members[name] = &Type{ + object: obj, + pkg: pkg, + } + + case *types.Const: + c := &NamedConst{ + object: obj, + Value: NewConst(obj.Val(), obj.Type()), + pkg: pkg, + } + pkg.values[obj] = c.Value + pkg.Members[name] = c + + case *types.Var: + g := &Global{ + Pkg: pkg, + name: name, + object: obj, + typ: types.NewPointer(obj.Type()), // address + pos: obj.Pos(), + } + pkg.values[obj] = g + pkg.Members[name] = g + + case *types.Func: + sig := obj.Type().(*types.Signature) + if sig.Recv() == nil && name == "init" { + pkg.ninit++ + name = fmt.Sprintf("init#%d", pkg.ninit) + } + fn := &Function{ + name: name, + object: obj, + Signature: sig, + syntax: syntax, + pos: obj.Pos(), + Pkg: pkg, + Prog: pkg.Prog, + } + if syntax == nil { + fn.Synthetic = "loaded from gc object file" + } + + pkg.values[obj] = fn + if sig.Recv() == nil { + pkg.Members[name] = fn // package-level function + } + + default: // (incl. *types.Package) + panic("unexpected Object type: " + obj.String()) + } +} + +// membersFromDecl populates package pkg with members for each +// typechecker object (var, func, const or type) associated with the +// specified decl. +// +func membersFromDecl(pkg *Package, decl ast.Decl) { + switch decl := decl.(type) { + case *ast.GenDecl: // import, const, type or var + switch decl.Tok { + case token.CONST: + for _, spec := range decl.Specs { + for _, id := range spec.(*ast.ValueSpec).Names { + if !isBlankIdent(id) { + memberFromObject(pkg, pkg.info.Defs[id], nil) + } + } + } + + case token.VAR: + for _, spec := range decl.Specs { + for _, id := range spec.(*ast.ValueSpec).Names { + if !isBlankIdent(id) { + memberFromObject(pkg, pkg.info.Defs[id], spec) + } + } + } + + case token.TYPE: + for _, spec := range decl.Specs { + id := spec.(*ast.TypeSpec).Name + if !isBlankIdent(id) { + memberFromObject(pkg, pkg.info.Defs[id], nil) + } + } + } + + case *ast.FuncDecl: + id := decl.Name + if !isBlankIdent(id) { + memberFromObject(pkg, pkg.info.Defs[id], decl) + } + } +} + +// CreatePackage constructs and returns an SSA Package from the +// specified type-checked, error-free file ASTs, and populates its +// Members mapping. +// +// importable determines whether this package should be returned by a +// subsequent call to ImportedPackage(pkg.Path()). +// +// The real work of building SSA form for each function is not done +// until a subsequent call to Package.Build(). +// +func (prog *Program) CreatePackage(pkg *types.Package, files []*ast.File, info *types.Info, importable bool) *Package { + p := &Package{ + Prog: prog, + Members: make(map[string]Member), + values: make(map[types.Object]Value), + Pkg: pkg, + info: info, // transient (CREATE and BUILD phases) + files: files, // transient (CREATE and BUILD phases) + } + + // Add init() function. + p.init = &Function{ + name: "init", + Signature: new(types.Signature), + Synthetic: "package initializer", + Pkg: p, + Prog: prog, + } + p.Members[p.init.name] = p.init + + // CREATE phase. + // Allocate all package members: vars, funcs, consts and types. + if len(files) > 0 { + // Go source package. + for _, file := range files { + for _, decl := range file.Decls { + membersFromDecl(p, decl) + } + } + } else { + // GC-compiled binary package (or "unsafe") + // No code. + // No position information. + scope := p.Pkg.Scope() + for _, name := range scope.Names() { + obj := scope.Lookup(name) + memberFromObject(p, obj, nil) + if obj, ok := obj.(*types.TypeName); ok { + if named, ok := obj.Type().(*types.Named); ok { + for i, n := 0, named.NumMethods(); i < n; i++ { + memberFromObject(p, named.Method(i), nil) + } + } + } + } + } + + if prog.mode&BareInits == 0 { + // Add initializer guard variable. + initguard := &Global{ + Pkg: p, + name: "init$guard", + typ: types.NewPointer(tBool), + } + p.Members[initguard.Name()] = initguard + } + + if prog.mode&GlobalDebug != 0 { + p.SetDebugMode(true) + } + + if prog.mode&PrintPackages != 0 { + printMu.Lock() + p.WriteTo(os.Stdout) + printMu.Unlock() + } + + if importable { + prog.imported[p.Pkg.Path()] = p + } + prog.packages[p.Pkg] = p + + return p +} + +// printMu serializes printing of Packages/Functions to stdout. +var printMu sync.Mutex + +// AllPackages returns a new slice containing all packages in the +// program prog in unspecified order. +// +func (prog *Program) AllPackages() []*Package { + pkgs := make([]*Package, 0, len(prog.packages)) + for _, pkg := range prog.packages { + pkgs = append(pkgs, pkg) + } + return pkgs +} + +// ImportedPackage returns the importable SSA Package whose import +// path is path, or nil if no such SSA package has been created. +// +// Not all packages are importable. For example, no import +// declaration can resolve to the x_test package created by 'go test' +// or the ad-hoc main package created 'go build foo.go'. +// +func (prog *Program) ImportedPackage(path string) *Package { + return prog.imported[path] +} diff --git a/vendor/honnef.co/go/tools/ssa/doc.go b/vendor/honnef.co/go/tools/ssa/doc.go new file mode 100644 index 0000000..57474dd --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/doc.go @@ -0,0 +1,123 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package ssa defines a representation of the elements of Go programs +// (packages, types, functions, variables and constants) using a +// static single-assignment (SSA) form intermediate representation +// (IR) for the bodies of functions. +// +// THIS INTERFACE IS EXPERIMENTAL AND IS LIKELY TO CHANGE. +// +// For an introduction to SSA form, see +// http://en.wikipedia.org/wiki/Static_single_assignment_form. +// This page provides a broader reading list: +// http://www.dcs.gla.ac.uk/~jsinger/ssa.html. +// +// The level of abstraction of the SSA form is intentionally close to +// the source language to facilitate construction of source analysis +// tools. It is not intended for machine code generation. +// +// All looping, branching and switching constructs are replaced with +// unstructured control flow. Higher-level control flow constructs +// such as multi-way branch can be reconstructed as needed; see +// ssautil.Switches() for an example. +// +// To construct an SSA-form program, call ssautil.CreateProgram on a +// loader.Program, a set of type-checked packages created from +// parsed Go source files. The resulting ssa.Program contains all the +// packages and their members, but SSA code is not created for +// function bodies until a subsequent call to (*Package).Build. +// +// The builder initially builds a naive SSA form in which all local +// variables are addresses of stack locations with explicit loads and +// stores. Registerisation of eligible locals and φ-node insertion +// using dominance and dataflow are then performed as a second pass +// called "lifting" to improve the accuracy and performance of +// subsequent analyses; this pass can be skipped by setting the +// NaiveForm builder flag. +// +// The primary interfaces of this package are: +// +// - Member: a named member of a Go package. +// - Value: an expression that yields a value. +// - Instruction: a statement that consumes values and performs computation. +// - Node: a Value or Instruction (emphasizing its membership in the SSA value graph) +// +// A computation that yields a result implements both the Value and +// Instruction interfaces. The following table shows for each +// concrete type which of these interfaces it implements. +// +// Value? Instruction? Member? +// *Alloc ✔ ✔ +// *BinOp ✔ ✔ +// *Builtin ✔ +// *Call ✔ ✔ +// *ChangeInterface ✔ ✔ +// *ChangeType ✔ ✔ +// *Const ✔ +// *Convert ✔ ✔ +// *DebugRef ✔ +// *Defer ✔ +// *Extract ✔ ✔ +// *Field ✔ ✔ +// *FieldAddr ✔ ✔ +// *FreeVar ✔ +// *Function ✔ ✔ (func) +// *Global ✔ ✔ (var) +// *Go ✔ +// *If ✔ +// *Index ✔ ✔ +// *IndexAddr ✔ ✔ +// *Jump ✔ +// *Lookup ✔ ✔ +// *MakeChan ✔ ✔ +// *MakeClosure ✔ ✔ +// *MakeInterface ✔ ✔ +// *MakeMap ✔ ✔ +// *MakeSlice ✔ ✔ +// *MapUpdate ✔ +// *NamedConst ✔ (const) +// *Next ✔ ✔ +// *Panic ✔ +// *Parameter ✔ +// *Phi ✔ ✔ +// *Range ✔ ✔ +// *Return ✔ +// *RunDefers ✔ +// *Select ✔ ✔ +// *Send ✔ +// *Slice ✔ ✔ +// *Store ✔ +// *Type ✔ (type) +// *TypeAssert ✔ ✔ +// *UnOp ✔ ✔ +// +// Other key types in this package include: Program, Package, Function +// and BasicBlock. +// +// The program representation constructed by this package is fully +// resolved internally, i.e. it does not rely on the names of Values, +// Packages, Functions, Types or BasicBlocks for the correct +// interpretation of the program. Only the identities of objects and +// the topology of the SSA and type graphs are semantically +// significant. (There is one exception: Ids, used to identify field +// and method names, contain strings.) Avoidance of name-based +// operations simplifies the implementation of subsequent passes and +// can make them very efficient. Many objects are nonetheless named +// to aid in debugging, but it is not essential that the names be +// either accurate or unambiguous. The public API exposes a number of +// name-based maps for client convenience. +// +// The ssa/ssautil package provides various utilities that depend only +// on the public API of this package. +// +// TODO(adonovan): Consider the exceptional control-flow implications +// of defer and recover(). +// +// TODO(adonovan): write a how-to document for all the various cases +// of trying to determine corresponding elements across the four +// domains of source locations, ast.Nodes, types.Objects, +// ssa.Values/Instructions. +// +package ssa // import "honnef.co/go/tools/ssa" diff --git a/vendor/honnef.co/go/tools/ssa/dom.go b/vendor/honnef.co/go/tools/ssa/dom.go new file mode 100644 index 0000000..12ef430 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/dom.go @@ -0,0 +1,341 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssa + +// This file defines algorithms related to dominance. + +// Dominator tree construction ---------------------------------------- +// +// We use the algorithm described in Lengauer & Tarjan. 1979. A fast +// algorithm for finding dominators in a flowgraph. +// http://doi.acm.org/10.1145/357062.357071 +// +// We also apply the optimizations to SLT described in Georgiadis et +// al, Finding Dominators in Practice, JGAA 2006, +// http://jgaa.info/accepted/2006/GeorgiadisTarjanWerneck2006.10.1.pdf +// to avoid the need for buckets of size > 1. + +import ( + "bytes" + "fmt" + "math/big" + "os" + "sort" +) + +// Idom returns the block that immediately dominates b: +// its parent in the dominator tree, if any. +// Neither the entry node (b.Index==0) nor recover node +// (b==b.Parent().Recover()) have a parent. +// +func (b *BasicBlock) Idom() *BasicBlock { return b.dom.idom } + +// Dominees returns the list of blocks that b immediately dominates: +// its children in the dominator tree. +// +func (b *BasicBlock) Dominees() []*BasicBlock { return b.dom.children } + +// Dominates reports whether b dominates c. +func (b *BasicBlock) Dominates(c *BasicBlock) bool { + return b.dom.pre <= c.dom.pre && c.dom.post <= b.dom.post +} + +type byDomPreorder []*BasicBlock + +func (a byDomPreorder) Len() int { return len(a) } +func (a byDomPreorder) Swap(i, j int) { a[i], a[j] = a[j], a[i] } +func (a byDomPreorder) Less(i, j int) bool { return a[i].dom.pre < a[j].dom.pre } + +// DomPreorder returns a new slice containing the blocks of f in +// dominator tree preorder. +// +func (f *Function) DomPreorder() []*BasicBlock { + n := len(f.Blocks) + order := make(byDomPreorder, n, n) + copy(order, f.Blocks) + sort.Sort(order) + return order +} + +// domInfo contains a BasicBlock's dominance information. +type domInfo struct { + idom *BasicBlock // immediate dominator (parent in domtree) + children []*BasicBlock // nodes immediately dominated by this one + pre, post int32 // pre- and post-order numbering within domtree +} + +// ltState holds the working state for Lengauer-Tarjan algorithm +// (during which domInfo.pre is repurposed for CFG DFS preorder number). +type ltState struct { + // Each slice is indexed by b.Index. + sdom []*BasicBlock // b's semidominator + parent []*BasicBlock // b's parent in DFS traversal of CFG + ancestor []*BasicBlock // b's ancestor with least sdom +} + +// dfs implements the depth-first search part of the LT algorithm. +func (lt *ltState) dfs(v *BasicBlock, i int32, preorder []*BasicBlock) int32 { + preorder[i] = v + v.dom.pre = i // For now: DFS preorder of spanning tree of CFG + i++ + lt.sdom[v.Index] = v + lt.link(nil, v) + for _, w := range v.Succs { + if lt.sdom[w.Index] == nil { + lt.parent[w.Index] = v + i = lt.dfs(w, i, preorder) + } + } + return i +} + +// eval implements the EVAL part of the LT algorithm. +func (lt *ltState) eval(v *BasicBlock) *BasicBlock { + // TODO(adonovan): opt: do path compression per simple LT. + u := v + for ; lt.ancestor[v.Index] != nil; v = lt.ancestor[v.Index] { + if lt.sdom[v.Index].dom.pre < lt.sdom[u.Index].dom.pre { + u = v + } + } + return u +} + +// link implements the LINK part of the LT algorithm. +func (lt *ltState) link(v, w *BasicBlock) { + lt.ancestor[w.Index] = v +} + +// buildDomTree computes the dominator tree of f using the LT algorithm. +// Precondition: all blocks are reachable (e.g. optimizeBlocks has been run). +// +func buildDomTree(f *Function) { + // The step numbers refer to the original LT paper; the + // reordering is due to Georgiadis. + + // Clear any previous domInfo. + for _, b := range f.Blocks { + b.dom = domInfo{} + } + + n := len(f.Blocks) + // Allocate space for 5 contiguous [n]*BasicBlock arrays: + // sdom, parent, ancestor, preorder, buckets. + space := make([]*BasicBlock, 5*n, 5*n) + lt := ltState{ + sdom: space[0:n], + parent: space[n : 2*n], + ancestor: space[2*n : 3*n], + } + + // Step 1. Number vertices by depth-first preorder. + preorder := space[3*n : 4*n] + root := f.Blocks[0] + prenum := lt.dfs(root, 0, preorder) + recover := f.Recover + if recover != nil { + lt.dfs(recover, prenum, preorder) + } + + buckets := space[4*n : 5*n] + copy(buckets, preorder) + + // In reverse preorder... + for i := int32(n) - 1; i > 0; i-- { + w := preorder[i] + + // Step 3. Implicitly define the immediate dominator of each node. + for v := buckets[i]; v != w; v = buckets[v.dom.pre] { + u := lt.eval(v) + if lt.sdom[u.Index].dom.pre < i { + v.dom.idom = u + } else { + v.dom.idom = w + } + } + + // Step 2. Compute the semidominators of all nodes. + lt.sdom[w.Index] = lt.parent[w.Index] + for _, v := range w.Preds { + u := lt.eval(v) + if lt.sdom[u.Index].dom.pre < lt.sdom[w.Index].dom.pre { + lt.sdom[w.Index] = lt.sdom[u.Index] + } + } + + lt.link(lt.parent[w.Index], w) + + if lt.parent[w.Index] == lt.sdom[w.Index] { + w.dom.idom = lt.parent[w.Index] + } else { + buckets[i] = buckets[lt.sdom[w.Index].dom.pre] + buckets[lt.sdom[w.Index].dom.pre] = w + } + } + + // The final 'Step 3' is now outside the loop. + for v := buckets[0]; v != root; v = buckets[v.dom.pre] { + v.dom.idom = root + } + + // Step 4. Explicitly define the immediate dominator of each + // node, in preorder. + for _, w := range preorder[1:] { + if w == root || w == recover { + w.dom.idom = nil + } else { + if w.dom.idom != lt.sdom[w.Index] { + w.dom.idom = w.dom.idom.dom.idom + } + // Calculate Children relation as inverse of Idom. + w.dom.idom.dom.children = append(w.dom.idom.dom.children, w) + } + } + + pre, post := numberDomTree(root, 0, 0) + if recover != nil { + numberDomTree(recover, pre, post) + } + + // printDomTreeDot(os.Stderr, f) // debugging + // printDomTreeText(os.Stderr, root, 0) // debugging + + if f.Prog.mode&SanityCheckFunctions != 0 { + sanityCheckDomTree(f) + } +} + +// numberDomTree sets the pre- and post-order numbers of a depth-first +// traversal of the dominator tree rooted at v. These are used to +// answer dominance queries in constant time. +// +func numberDomTree(v *BasicBlock, pre, post int32) (int32, int32) { + v.dom.pre = pre + pre++ + for _, child := range v.dom.children { + pre, post = numberDomTree(child, pre, post) + } + v.dom.post = post + post++ + return pre, post +} + +// Testing utilities ---------------------------------------- + +// sanityCheckDomTree checks the correctness of the dominator tree +// computed by the LT algorithm by comparing against the dominance +// relation computed by a naive Kildall-style forward dataflow +// analysis (Algorithm 10.16 from the "Dragon" book). +// +func sanityCheckDomTree(f *Function) { + n := len(f.Blocks) + + // D[i] is the set of blocks that dominate f.Blocks[i], + // represented as a bit-set of block indices. + D := make([]big.Int, n) + + one := big.NewInt(1) + + // all is the set of all blocks; constant. + var all big.Int + all.Set(one).Lsh(&all, uint(n)).Sub(&all, one) + + // Initialization. + for i, b := range f.Blocks { + if i == 0 || b == f.Recover { + // A root is dominated only by itself. + D[i].SetBit(&D[0], 0, 1) + } else { + // All other blocks are (initially) dominated + // by every block. + D[i].Set(&all) + } + } + + // Iteration until fixed point. + for changed := true; changed; { + changed = false + for i, b := range f.Blocks { + if i == 0 || b == f.Recover { + continue + } + // Compute intersection across predecessors. + var x big.Int + x.Set(&all) + for _, pred := range b.Preds { + x.And(&x, &D[pred.Index]) + } + x.SetBit(&x, i, 1) // a block always dominates itself. + if D[i].Cmp(&x) != 0 { + D[i].Set(&x) + changed = true + } + } + } + + // Check the entire relation. O(n^2). + // The Recover block (if any) must be treated specially so we skip it. + ok := true + for i := 0; i < n; i++ { + for j := 0; j < n; j++ { + b, c := f.Blocks[i], f.Blocks[j] + if c == f.Recover { + continue + } + actual := b.Dominates(c) + expected := D[j].Bit(i) == 1 + if actual != expected { + fmt.Fprintf(os.Stderr, "dominates(%s, %s)==%t, want %t\n", b, c, actual, expected) + ok = false + } + } + } + + preorder := f.DomPreorder() + for _, b := range f.Blocks { + if got := preorder[b.dom.pre]; got != b { + fmt.Fprintf(os.Stderr, "preorder[%d]==%s, want %s\n", b.dom.pre, got, b) + ok = false + } + } + + if !ok { + panic("sanityCheckDomTree failed for " + f.String()) + } + +} + +// Printing functions ---------------------------------------- + +// printDomTree prints the dominator tree as text, using indentation. +func printDomTreeText(buf *bytes.Buffer, v *BasicBlock, indent int) { + fmt.Fprintf(buf, "%*s%s\n", 4*indent, "", v) + for _, child := range v.dom.children { + printDomTreeText(buf, child, indent+1) + } +} + +// printDomTreeDot prints the dominator tree of f in AT&T GraphViz +// (.dot) format. +func printDomTreeDot(buf *bytes.Buffer, f *Function) { + fmt.Fprintln(buf, "//", f) + fmt.Fprintln(buf, "digraph domtree {") + for i, b := range f.Blocks { + v := b.dom + fmt.Fprintf(buf, "\tn%d [label=\"%s (%d, %d)\",shape=\"rectangle\"];\n", v.pre, b, v.pre, v.post) + // TODO(adonovan): improve appearance of edges + // belonging to both dominator tree and CFG. + + // Dominator tree edge. + if i != 0 { + fmt.Fprintf(buf, "\tn%d -> n%d [style=\"solid\",weight=100];\n", v.idom.dom.pre, v.pre) + } + // CFG edges. + for _, pred := range b.Preds { + fmt.Fprintf(buf, "\tn%d -> n%d [style=\"dotted\",weight=0];\n", pred.dom.pre, v.pre) + } + } + fmt.Fprintln(buf, "}") +} diff --git a/vendor/honnef.co/go/tools/ssa/emit.go b/vendor/honnef.co/go/tools/ssa/emit.go new file mode 100644 index 0000000..400da21 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/emit.go @@ -0,0 +1,475 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// Helpers for emitting SSA instructions. + +import ( + "fmt" + "go/ast" + "go/token" + "go/types" +) + +// emitNew emits to f a new (heap Alloc) instruction allocating an +// object of type typ. pos is the optional source location. +// +func emitNew(f *Function, typ types.Type, pos token.Pos) *Alloc { + v := &Alloc{Heap: true} + v.setType(types.NewPointer(typ)) + v.setPos(pos) + f.emit(v) + return v +} + +// emitLoad emits to f an instruction to load the address addr into a +// new temporary, and returns the value so defined. +// +func emitLoad(f *Function, addr Value) *UnOp { + v := &UnOp{Op: token.MUL, X: addr} + v.setType(deref(addr.Type())) + f.emit(v) + return v +} + +// emitDebugRef emits to f a DebugRef pseudo-instruction associating +// expression e with value v. +// +func emitDebugRef(f *Function, e ast.Expr, v Value, isAddr bool) { + if !f.debugInfo() { + return // debugging not enabled + } + if v == nil || e == nil { + panic("nil") + } + var obj types.Object + e = unparen(e) + if id, ok := e.(*ast.Ident); ok { + if isBlankIdent(id) { + return + } + obj = f.Pkg.objectOf(id) + switch obj.(type) { + case *types.Nil, *types.Const, *types.Builtin: + return + } + } + f.emit(&DebugRef{ + X: v, + Expr: e, + IsAddr: isAddr, + object: obj, + }) +} + +// emitArith emits to f code to compute the binary operation op(x, y) +// where op is an eager shift, logical or arithmetic operation. +// (Use emitCompare() for comparisons and Builder.logicalBinop() for +// non-eager operations.) +// +func emitArith(f *Function, op token.Token, x, y Value, t types.Type, pos token.Pos) Value { + switch op { + case token.SHL, token.SHR: + x = emitConv(f, x, t) + // y may be signed or an 'untyped' constant. + // TODO(adonovan): whence signed values? + if b, ok := y.Type().Underlying().(*types.Basic); ok && b.Info()&types.IsUnsigned == 0 { + y = emitConv(f, y, types.Typ[types.Uint64]) + } + + case token.ADD, token.SUB, token.MUL, token.QUO, token.REM, token.AND, token.OR, token.XOR, token.AND_NOT: + x = emitConv(f, x, t) + y = emitConv(f, y, t) + + default: + panic("illegal op in emitArith: " + op.String()) + + } + v := &BinOp{ + Op: op, + X: x, + Y: y, + } + v.setPos(pos) + v.setType(t) + return f.emit(v) +} + +// emitCompare emits to f code compute the boolean result of +// comparison comparison 'x op y'. +// +func emitCompare(f *Function, op token.Token, x, y Value, pos token.Pos) Value { + xt := x.Type().Underlying() + yt := y.Type().Underlying() + + // Special case to optimise a tagless SwitchStmt so that + // these are equivalent + // switch { case e: ...} + // switch true { case e: ... } + // if e==true { ... } + // even in the case when e's type is an interface. + // TODO(adonovan): opt: generalise to x==true, false!=y, etc. + if x == vTrue && op == token.EQL { + if yt, ok := yt.(*types.Basic); ok && yt.Info()&types.IsBoolean != 0 { + return y + } + } + + if types.Identical(xt, yt) { + // no conversion necessary + } else if _, ok := xt.(*types.Interface); ok { + y = emitConv(f, y, x.Type()) + } else if _, ok := yt.(*types.Interface); ok { + x = emitConv(f, x, y.Type()) + } else if _, ok := x.(*Const); ok { + x = emitConv(f, x, y.Type()) + } else if _, ok := y.(*Const); ok { + y = emitConv(f, y, x.Type()) + } else { + // other cases, e.g. channels. No-op. + } + + v := &BinOp{ + Op: op, + X: x, + Y: y, + } + v.setPos(pos) + v.setType(tBool) + return f.emit(v) +} + +// isValuePreserving returns true if a conversion from ut_src to +// ut_dst is value-preserving, i.e. just a change of type. +// Precondition: neither argument is a named type. +// +func isValuePreserving(ut_src, ut_dst types.Type) bool { + // Identical underlying types? + if structTypesIdentical(ut_dst, ut_src) { + return true + } + + switch ut_dst.(type) { + case *types.Chan: + // Conversion between channel types? + _, ok := ut_src.(*types.Chan) + return ok + + case *types.Pointer: + // Conversion between pointers with identical base types? + _, ok := ut_src.(*types.Pointer) + return ok + } + return false +} + +// emitConv emits to f code to convert Value val to exactly type typ, +// and returns the converted value. Implicit conversions are required +// by language assignability rules in assignments, parameter passing, +// etc. Conversions cannot fail dynamically. +// +func emitConv(f *Function, val Value, typ types.Type) Value { + t_src := val.Type() + + // Identical types? Conversion is a no-op. + if types.Identical(t_src, typ) { + return val + } + + ut_dst := typ.Underlying() + ut_src := t_src.Underlying() + + // Just a change of type, but not value or representation? + if isValuePreserving(ut_src, ut_dst) { + c := &ChangeType{X: val} + c.setType(typ) + return f.emit(c) + } + + // Conversion to, or construction of a value of, an interface type? + if _, ok := ut_dst.(*types.Interface); ok { + // Assignment from one interface type to another? + if _, ok := ut_src.(*types.Interface); ok { + c := &ChangeInterface{X: val} + c.setType(typ) + return f.emit(c) + } + + // Untyped nil constant? Return interface-typed nil constant. + if ut_src == tUntypedNil { + return nilConst(typ) + } + + // Convert (non-nil) "untyped" literals to their default type. + if t, ok := ut_src.(*types.Basic); ok && t.Info()&types.IsUntyped != 0 { + val = emitConv(f, val, DefaultType(ut_src)) + } + + f.Pkg.Prog.needMethodsOf(val.Type()) + mi := &MakeInterface{X: val} + mi.setType(typ) + return f.emit(mi) + } + + // Conversion of a compile-time constant value? + if c, ok := val.(*Const); ok { + if _, ok := ut_dst.(*types.Basic); ok || c.IsNil() { + // Conversion of a compile-time constant to + // another constant type results in a new + // constant of the destination type and + // (initially) the same abstract value. + // We don't truncate the value yet. + return NewConst(c.Value, typ) + } + + // We're converting from constant to non-constant type, + // e.g. string -> []byte/[]rune. + } + + // A representation-changing conversion? + // At least one of {ut_src,ut_dst} must be *Basic. + // (The other may be []byte or []rune.) + _, ok1 := ut_src.(*types.Basic) + _, ok2 := ut_dst.(*types.Basic) + if ok1 || ok2 { + c := &Convert{X: val} + c.setType(typ) + return f.emit(c) + } + + panic(fmt.Sprintf("in %s: cannot convert %s (%s) to %s", f, val, val.Type(), typ)) +} + +// emitStore emits to f an instruction to store value val at location +// addr, applying implicit conversions as required by assignability rules. +// +func emitStore(f *Function, addr, val Value, pos token.Pos) *Store { + s := &Store{ + Addr: addr, + Val: emitConv(f, val, deref(addr.Type())), + pos: pos, + } + f.emit(s) + return s +} + +// emitJump emits to f a jump to target, and updates the control-flow graph. +// Postcondition: f.currentBlock is nil. +// +func emitJump(f *Function, target *BasicBlock) { + b := f.currentBlock + b.emit(new(Jump)) + addEdge(b, target) + f.currentBlock = nil +} + +func (b *BasicBlock) emitJump(target *BasicBlock) { + b.emit(new(Jump)) + addEdge(b, target) +} + +// emitIf emits to f a conditional jump to tblock or fblock based on +// cond, and updates the control-flow graph. +// Postcondition: f.currentBlock is nil. +// +func emitIf(f *Function, cond Value, tblock, fblock *BasicBlock) { + b := f.currentBlock + b.emit(&If{Cond: cond}) + addEdge(b, tblock) + addEdge(b, fblock) + f.currentBlock = nil +} + +// emitExtract emits to f an instruction to extract the index'th +// component of tuple. It returns the extracted value. +// +func emitExtract(f *Function, tuple Value, index int) Value { + e := &Extract{Tuple: tuple, Index: index} + e.setType(tuple.Type().(*types.Tuple).At(index).Type()) + return f.emit(e) +} + +// emitTypeAssert emits to f a type assertion value := x.(t) and +// returns the value. x.Type() must be an interface. +// +func emitTypeAssert(f *Function, x Value, t types.Type, pos token.Pos) Value { + a := &TypeAssert{X: x, AssertedType: t} + a.setPos(pos) + a.setType(t) + return f.emit(a) +} + +// emitTypeTest emits to f a type test value,ok := x.(t) and returns +// a (value, ok) tuple. x.Type() must be an interface. +// +func emitTypeTest(f *Function, x Value, t types.Type, pos token.Pos) Value { + a := &TypeAssert{ + X: x, + AssertedType: t, + CommaOk: true, + } + a.setPos(pos) + a.setType(types.NewTuple( + newVar("value", t), + varOk, + )) + return f.emit(a) +} + +// emitTailCall emits to f a function call in tail position. The +// caller is responsible for all fields of 'call' except its type. +// Intended for wrapper methods. +// Precondition: f does/will not use deferred procedure calls. +// Postcondition: f.currentBlock is nil. +// +func emitTailCall(f *Function, call *Call) { + tresults := f.Signature.Results() + nr := tresults.Len() + if nr == 1 { + call.typ = tresults.At(0).Type() + } else { + call.typ = tresults + } + tuple := f.emit(call) + var ret Return + switch nr { + case 0: + // no-op + case 1: + ret.Results = []Value{tuple} + default: + for i := 0; i < nr; i++ { + v := emitExtract(f, tuple, i) + // TODO(adonovan): in principle, this is required: + // v = emitConv(f, o.Type, f.Signature.Results[i].Type) + // but in practice emitTailCall is only used when + // the types exactly match. + ret.Results = append(ret.Results, v) + } + } + f.emit(&ret) + f.currentBlock = nil +} + +// emitImplicitSelections emits to f code to apply the sequence of +// implicit field selections specified by indices to base value v, and +// returns the selected value. +// +// If v is the address of a struct, the result will be the address of +// a field; if it is the value of a struct, the result will be the +// value of a field. +// +func emitImplicitSelections(f *Function, v Value, indices []int) Value { + for _, index := range indices { + fld := deref(v.Type()).Underlying().(*types.Struct).Field(index) + + if isPointer(v.Type()) { + instr := &FieldAddr{ + X: v, + Field: index, + } + instr.setType(types.NewPointer(fld.Type())) + v = f.emit(instr) + // Load the field's value iff indirectly embedded. + if isPointer(fld.Type()) { + v = emitLoad(f, v) + } + } else { + instr := &Field{ + X: v, + Field: index, + } + instr.setType(fld.Type()) + v = f.emit(instr) + } + } + return v +} + +// emitFieldSelection emits to f code to select the index'th field of v. +// +// If wantAddr, the input must be a pointer-to-struct and the result +// will be the field's address; otherwise the result will be the +// field's value. +// Ident id is used for position and debug info. +// +func emitFieldSelection(f *Function, v Value, index int, wantAddr bool, id *ast.Ident) Value { + fld := deref(v.Type()).Underlying().(*types.Struct).Field(index) + if isPointer(v.Type()) { + instr := &FieldAddr{ + X: v, + Field: index, + } + instr.setPos(id.Pos()) + instr.setType(types.NewPointer(fld.Type())) + v = f.emit(instr) + // Load the field's value iff we don't want its address. + if !wantAddr { + v = emitLoad(f, v) + } + } else { + instr := &Field{ + X: v, + Field: index, + } + instr.setPos(id.Pos()) + instr.setType(fld.Type()) + v = f.emit(instr) + } + emitDebugRef(f, id, v, wantAddr) + return v +} + +// zeroValue emits to f code to produce a zero value of type t, +// and returns it. +// +func zeroValue(f *Function, t types.Type) Value { + switch t.Underlying().(type) { + case *types.Struct, *types.Array: + return emitLoad(f, f.addLocal(t, token.NoPos)) + default: + return zeroConst(t) + } +} + +// createRecoverBlock emits to f a block of code to return after a +// recovered panic, and sets f.Recover to it. +// +// If f's result parameters are named, the code loads and returns +// their current values, otherwise it returns the zero values of their +// type. +// +// Idempotent. +// +func createRecoverBlock(f *Function) { + if f.Recover != nil { + return // already created + } + saved := f.currentBlock + + f.Recover = f.newBasicBlock("recover") + f.currentBlock = f.Recover + + var results []Value + if f.namedResults != nil { + // Reload NRPs to form value tuple. + for _, r := range f.namedResults { + results = append(results, emitLoad(f, r)) + } + } else { + R := f.Signature.Results() + for i, n := 0, R.Len(); i < n; i++ { + T := R.At(i).Type() + + // Return zero value of each result type. + results = append(results, zeroValue(f, T)) + } + } + f.emit(&Return{Results: results}) + + f.currentBlock = saved +} diff --git a/vendor/honnef.co/go/tools/ssa/func.go b/vendor/honnef.co/go/tools/ssa/func.go new file mode 100644 index 0000000..86a3da7 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/func.go @@ -0,0 +1,703 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// This file implements the Function and BasicBlock types. + +import ( + "bytes" + "fmt" + "go/ast" + "go/token" + "go/types" + "io" + "os" + "strings" +) + +// addEdge adds a control-flow graph edge from from to to. +func addEdge(from, to *BasicBlock) { + from.Succs = append(from.Succs, to) + to.Preds = append(to.Preds, from) +} + +// Parent returns the function that contains block b. +func (b *BasicBlock) Parent() *Function { return b.parent } + +// String returns a human-readable label of this block. +// It is not guaranteed unique within the function. +// +func (b *BasicBlock) String() string { + return fmt.Sprintf("%d", b.Index) +} + +// emit appends an instruction to the current basic block. +// If the instruction defines a Value, it is returned. +// +func (b *BasicBlock) emit(i Instruction) Value { + i.setBlock(b) + b.Instrs = append(b.Instrs, i) + v, _ := i.(Value) + return v +} + +// predIndex returns the i such that b.Preds[i] == c or panics if +// there is none. +func (b *BasicBlock) predIndex(c *BasicBlock) int { + for i, pred := range b.Preds { + if pred == c { + return i + } + } + panic(fmt.Sprintf("no edge %s -> %s", c, b)) +} + +// hasPhi returns true if b.Instrs contains φ-nodes. +func (b *BasicBlock) hasPhi() bool { + _, ok := b.Instrs[0].(*Phi) + return ok +} + +func (b *BasicBlock) Phis() []Instruction { + return b.phis() +} + +// phis returns the prefix of b.Instrs containing all the block's φ-nodes. +func (b *BasicBlock) phis() []Instruction { + for i, instr := range b.Instrs { + if _, ok := instr.(*Phi); !ok { + return b.Instrs[:i] + } + } + return nil // unreachable in well-formed blocks +} + +// replacePred replaces all occurrences of p in b's predecessor list with q. +// Ordinarily there should be at most one. +// +func (b *BasicBlock) replacePred(p, q *BasicBlock) { + for i, pred := range b.Preds { + if pred == p { + b.Preds[i] = q + } + } +} + +// replaceSucc replaces all occurrences of p in b's successor list with q. +// Ordinarily there should be at most one. +// +func (b *BasicBlock) replaceSucc(p, q *BasicBlock) { + for i, succ := range b.Succs { + if succ == p { + b.Succs[i] = q + } + } +} + +func (b *BasicBlock) RemovePred(p *BasicBlock) { + b.removePred(p) +} + +// removePred removes all occurrences of p in b's +// predecessor list and φ-nodes. +// Ordinarily there should be at most one. +// +func (b *BasicBlock) removePred(p *BasicBlock) { + phis := b.phis() + + // We must preserve edge order for φ-nodes. + j := 0 + for i, pred := range b.Preds { + if pred != p { + b.Preds[j] = b.Preds[i] + // Strike out φ-edge too. + for _, instr := range phis { + phi := instr.(*Phi) + phi.Edges[j] = phi.Edges[i] + } + j++ + } + } + // Nil out b.Preds[j:] and φ-edges[j:] to aid GC. + for i := j; i < len(b.Preds); i++ { + b.Preds[i] = nil + for _, instr := range phis { + instr.(*Phi).Edges[i] = nil + } + } + b.Preds = b.Preds[:j] + for _, instr := range phis { + phi := instr.(*Phi) + phi.Edges = phi.Edges[:j] + } +} + +// Destinations associated with unlabelled for/switch/select stmts. +// We push/pop one of these as we enter/leave each construct and for +// each BranchStmt we scan for the innermost target of the right type. +// +type targets struct { + tail *targets // rest of stack + _break *BasicBlock + _continue *BasicBlock + _fallthrough *BasicBlock +} + +// Destinations associated with a labelled block. +// We populate these as labels are encountered in forward gotos or +// labelled statements. +// +type lblock struct { + _goto *BasicBlock + _break *BasicBlock + _continue *BasicBlock +} + +// labelledBlock returns the branch target associated with the +// specified label, creating it if needed. +// +func (f *Function) labelledBlock(label *ast.Ident) *lblock { + lb := f.lblocks[label.Obj] + if lb == nil { + lb = &lblock{_goto: f.newBasicBlock(label.Name)} + if f.lblocks == nil { + f.lblocks = make(map[*ast.Object]*lblock) + } + f.lblocks[label.Obj] = lb + } + return lb +} + +// addParam adds a (non-escaping) parameter to f.Params of the +// specified name, type and source position. +// +func (f *Function) addParam(name string, typ types.Type, pos token.Pos) *Parameter { + v := &Parameter{ + name: name, + typ: typ, + pos: pos, + parent: f, + } + f.Params = append(f.Params, v) + return v +} + +func (f *Function) addParamObj(obj types.Object) *Parameter { + name := obj.Name() + if name == "" { + name = fmt.Sprintf("arg%d", len(f.Params)) + } + param := f.addParam(name, obj.Type(), obj.Pos()) + param.object = obj + return param +} + +// addSpilledParam declares a parameter that is pre-spilled to the +// stack; the function body will load/store the spilled location. +// Subsequent lifting will eliminate spills where possible. +// +func (f *Function) addSpilledParam(obj types.Object) { + param := f.addParamObj(obj) + spill := &Alloc{Comment: obj.Name()} + spill.setType(types.NewPointer(obj.Type())) + spill.setPos(obj.Pos()) + f.objects[obj] = spill + f.Locals = append(f.Locals, spill) + f.emit(spill) + f.emit(&Store{Addr: spill, Val: param}) +} + +// startBody initializes the function prior to generating SSA code for its body. +// Precondition: f.Type() already set. +// +func (f *Function) startBody() { + f.currentBlock = f.newBasicBlock("entry") + f.objects = make(map[types.Object]Value) // needed for some synthetics, e.g. init +} + +// createSyntacticParams populates f.Params and generates code (spills +// and named result locals) for all the parameters declared in the +// syntax. In addition it populates the f.objects mapping. +// +// Preconditions: +// f.startBody() was called. +// Postcondition: +// len(f.Params) == len(f.Signature.Params) + (f.Signature.Recv() ? 1 : 0) +// +func (f *Function) createSyntacticParams(recv *ast.FieldList, functype *ast.FuncType) { + // Receiver (at most one inner iteration). + if recv != nil { + for _, field := range recv.List { + for _, n := range field.Names { + f.addSpilledParam(f.Pkg.info.Defs[n]) + } + // Anonymous receiver? No need to spill. + if field.Names == nil { + f.addParamObj(f.Signature.Recv()) + } + } + } + + // Parameters. + if functype.Params != nil { + n := len(f.Params) // 1 if has recv, 0 otherwise + for _, field := range functype.Params.List { + for _, n := range field.Names { + f.addSpilledParam(f.Pkg.info.Defs[n]) + } + // Anonymous parameter? No need to spill. + if field.Names == nil { + f.addParamObj(f.Signature.Params().At(len(f.Params) - n)) + } + } + } + + // Named results. + if functype.Results != nil { + for _, field := range functype.Results.List { + // Implicit "var" decl of locals for named results. + for _, n := range field.Names { + f.namedResults = append(f.namedResults, f.addLocalForIdent(n)) + } + } + } +} + +// numberRegisters assigns numbers to all SSA registers +// (value-defining Instructions) in f, to aid debugging. +// (Non-Instruction Values are named at construction.) +// +func numberRegisters(f *Function) { + v := 0 + for _, b := range f.Blocks { + for _, instr := range b.Instrs { + switch instr.(type) { + case Value: + instr.(interface { + setNum(int) + }).setNum(v) + v++ + } + } + } +} + +// buildReferrers populates the def/use information in all non-nil +// Value.Referrers slice. +// Precondition: all such slices are initially empty. +func buildReferrers(f *Function) { + var rands []*Value + for _, b := range f.Blocks { + for _, instr := range b.Instrs { + rands = instr.Operands(rands[:0]) // recycle storage + for _, rand := range rands { + if r := *rand; r != nil { + if ref := r.Referrers(); ref != nil { + *ref = append(*ref, instr) + } + } + } + } + } +} + +// finishBody() finalizes the function after SSA code generation of its body. +func (f *Function) finishBody() { + f.objects = nil + f.currentBlock = nil + f.lblocks = nil + + // Don't pin the AST in memory (except in debug mode). + if n := f.syntax; n != nil && !f.debugInfo() { + f.syntax = extentNode{n.Pos(), n.End()} + } + + // Remove from f.Locals any Allocs that escape to the heap. + j := 0 + for _, l := range f.Locals { + if !l.Heap { + f.Locals[j] = l + j++ + } + } + // Nil out f.Locals[j:] to aid GC. + for i := j; i < len(f.Locals); i++ { + f.Locals[i] = nil + } + f.Locals = f.Locals[:j] + + optimizeBlocks(f) + + buildReferrers(f) + + buildDomTree(f) + + if f.Prog.mode&NaiveForm == 0 { + // For debugging pre-state of lifting pass: + // numberRegisters(f) + // f.WriteTo(os.Stderr) + lift(f) + } + + f.namedResults = nil // (used by lifting) + + numberRegisters(f) + + if f.Prog.mode&PrintFunctions != 0 { + printMu.Lock() + f.WriteTo(os.Stdout) + printMu.Unlock() + } + + if f.Prog.mode&SanityCheckFunctions != 0 { + mustSanityCheck(f, nil) + } +} + +func (f *Function) RemoveNilBlocks() { + f.removeNilBlocks() +} + +// removeNilBlocks eliminates nils from f.Blocks and updates each +// BasicBlock.Index. Use this after any pass that may delete blocks. +// +func (f *Function) removeNilBlocks() { + j := 0 + for _, b := range f.Blocks { + if b != nil { + b.Index = j + f.Blocks[j] = b + j++ + } + } + // Nil out f.Blocks[j:] to aid GC. + for i := j; i < len(f.Blocks); i++ { + f.Blocks[i] = nil + } + f.Blocks = f.Blocks[:j] +} + +// SetDebugMode sets the debug mode for package pkg. If true, all its +// functions will include full debug info. This greatly increases the +// size of the instruction stream, and causes Functions to depend upon +// the ASTs, potentially keeping them live in memory for longer. +// +func (pkg *Package) SetDebugMode(debug bool) { + // TODO(adonovan): do we want ast.File granularity? + pkg.debug = debug +} + +// debugInfo reports whether debug info is wanted for this function. +func (f *Function) debugInfo() bool { + return f.Pkg != nil && f.Pkg.debug +} + +// addNamedLocal creates a local variable, adds it to function f and +// returns it. Its name and type are taken from obj. Subsequent +// calls to f.lookup(obj) will return the same local. +// +func (f *Function) addNamedLocal(obj types.Object) *Alloc { + l := f.addLocal(obj.Type(), obj.Pos()) + l.Comment = obj.Name() + f.objects[obj] = l + return l +} + +func (f *Function) addLocalForIdent(id *ast.Ident) *Alloc { + return f.addNamedLocal(f.Pkg.info.Defs[id]) +} + +// addLocal creates an anonymous local variable of type typ, adds it +// to function f and returns it. pos is the optional source location. +// +func (f *Function) addLocal(typ types.Type, pos token.Pos) *Alloc { + v := &Alloc{} + v.setType(types.NewPointer(typ)) + v.setPos(pos) + f.Locals = append(f.Locals, v) + f.emit(v) + return v +} + +// lookup returns the address of the named variable identified by obj +// that is local to function f or one of its enclosing functions. +// If escaping, the reference comes from a potentially escaping pointer +// expression and the referent must be heap-allocated. +// +func (f *Function) lookup(obj types.Object, escaping bool) Value { + if v, ok := f.objects[obj]; ok { + if alloc, ok := v.(*Alloc); ok && escaping { + alloc.Heap = true + } + return v // function-local var (address) + } + + // Definition must be in an enclosing function; + // plumb it through intervening closures. + if f.parent == nil { + panic("no ssa.Value for " + obj.String()) + } + outer := f.parent.lookup(obj, true) // escaping + v := &FreeVar{ + name: obj.Name(), + typ: outer.Type(), + pos: outer.Pos(), + outer: outer, + parent: f, + } + f.objects[obj] = v + f.FreeVars = append(f.FreeVars, v) + return v +} + +// emit emits the specified instruction to function f. +func (f *Function) emit(instr Instruction) Value { + return f.currentBlock.emit(instr) +} + +// RelString returns the full name of this function, qualified by +// package name, receiver type, etc. +// +// The specific formatting rules are not guaranteed and may change. +// +// Examples: +// "math.IsNaN" // a package-level function +// "(*bytes.Buffer).Bytes" // a declared method or a wrapper +// "(*bytes.Buffer).Bytes$thunk" // thunk (func wrapping method; receiver is param 0) +// "(*bytes.Buffer).Bytes$bound" // bound (func wrapping method; receiver supplied by closure) +// "main.main$1" // an anonymous function in main +// "main.init#1" // a declared init function +// "main.init" // the synthesized package initializer +// +// When these functions are referred to from within the same package +// (i.e. from == f.Pkg.Object), they are rendered without the package path. +// For example: "IsNaN", "(*Buffer).Bytes", etc. +// +// All non-synthetic functions have distinct package-qualified names. +// (But two methods may have the same name "(T).f" if one is a synthetic +// wrapper promoting a non-exported method "f" from another package; in +// that case, the strings are equal but the identifiers "f" are distinct.) +// +func (f *Function) RelString(from *types.Package) string { + // Anonymous? + if f.parent != nil { + // An anonymous function's Name() looks like "parentName$1", + // but its String() should include the type/package/etc. + parent := f.parent.RelString(from) + for i, anon := range f.parent.AnonFuncs { + if anon == f { + return fmt.Sprintf("%s$%d", parent, 1+i) + } + } + + return f.name // should never happen + } + + // Method (declared or wrapper)? + if recv := f.Signature.Recv(); recv != nil { + return f.relMethod(from, recv.Type()) + } + + // Thunk? + if f.method != nil { + return f.relMethod(from, f.method.Recv()) + } + + // Bound? + if len(f.FreeVars) == 1 && strings.HasSuffix(f.name, "$bound") { + return f.relMethod(from, f.FreeVars[0].Type()) + } + + // Package-level function? + // Prefix with package name for cross-package references only. + if p := f.pkg(); p != nil && p != from { + return fmt.Sprintf("%s.%s", p.Path(), f.name) + } + + // Unknown. + return f.name +} + +func (f *Function) relMethod(from *types.Package, recv types.Type) string { + return fmt.Sprintf("(%s).%s", relType(recv, from), f.name) +} + +// writeSignature writes to buf the signature sig in declaration syntax. +func writeSignature(buf *bytes.Buffer, from *types.Package, name string, sig *types.Signature, params []*Parameter) { + buf.WriteString("func ") + if recv := sig.Recv(); recv != nil { + buf.WriteString("(") + if n := params[0].Name(); n != "" { + buf.WriteString(n) + buf.WriteString(" ") + } + types.WriteType(buf, params[0].Type(), types.RelativeTo(from)) + buf.WriteString(") ") + } + buf.WriteString(name) + types.WriteSignature(buf, sig, types.RelativeTo(from)) +} + +func (f *Function) pkg() *types.Package { + if f.Pkg != nil { + return f.Pkg.Pkg + } + return nil +} + +var _ io.WriterTo = (*Function)(nil) // *Function implements io.Writer + +func (f *Function) WriteTo(w io.Writer) (int64, error) { + var buf bytes.Buffer + WriteFunction(&buf, f) + n, err := w.Write(buf.Bytes()) + return int64(n), err +} + +// WriteFunction writes to buf a human-readable "disassembly" of f. +func WriteFunction(buf *bytes.Buffer, f *Function) { + fmt.Fprintf(buf, "# Name: %s\n", f.String()) + if f.Pkg != nil { + fmt.Fprintf(buf, "# Package: %s\n", f.Pkg.Pkg.Path()) + } + if syn := f.Synthetic; syn != "" { + fmt.Fprintln(buf, "# Synthetic:", syn) + } + if pos := f.Pos(); pos.IsValid() { + fmt.Fprintf(buf, "# Location: %s\n", f.Prog.Fset.Position(pos)) + } + + if f.parent != nil { + fmt.Fprintf(buf, "# Parent: %s\n", f.parent.Name()) + } + + if f.Recover != nil { + fmt.Fprintf(buf, "# Recover: %s\n", f.Recover) + } + + from := f.pkg() + + if f.FreeVars != nil { + buf.WriteString("# Free variables:\n") + for i, fv := range f.FreeVars { + fmt.Fprintf(buf, "# % 3d:\t%s %s\n", i, fv.Name(), relType(fv.Type(), from)) + } + } + + if len(f.Locals) > 0 { + buf.WriteString("# Locals:\n") + for i, l := range f.Locals { + fmt.Fprintf(buf, "# % 3d:\t%s %s\n", i, l.Name(), relType(deref(l.Type()), from)) + } + } + writeSignature(buf, from, f.Name(), f.Signature, f.Params) + buf.WriteString(":\n") + + if f.Blocks == nil { + buf.WriteString("\t(external)\n") + } + + // NB. column calculations are confused by non-ASCII + // characters and assume 8-space tabs. + const punchcard = 80 // for old time's sake. + const tabwidth = 8 + for _, b := range f.Blocks { + if b == nil { + // Corrupt CFG. + fmt.Fprintf(buf, ".nil:\n") + continue + } + n, _ := fmt.Fprintf(buf, "%d:", b.Index) + bmsg := fmt.Sprintf("%s P:%d S:%d", b.Comment, len(b.Preds), len(b.Succs)) + fmt.Fprintf(buf, "%*s%s\n", punchcard-1-n-len(bmsg), "", bmsg) + + if false { // CFG debugging + fmt.Fprintf(buf, "\t# CFG: %s --> %s --> %s\n", b.Preds, b, b.Succs) + } + for _, instr := range b.Instrs { + buf.WriteString("\t") + switch v := instr.(type) { + case Value: + l := punchcard - tabwidth + // Left-align the instruction. + if name := v.Name(); name != "" { + n, _ := fmt.Fprintf(buf, "%s = ", name) + l -= n + } + n, _ := buf.WriteString(instr.String()) + l -= n + // Right-align the type if there's space. + if t := v.Type(); t != nil { + buf.WriteByte(' ') + ts := relType(t, from) + l -= len(ts) + len(" ") // (spaces before and after type) + if l > 0 { + fmt.Fprintf(buf, "%*s", l, "") + } + buf.WriteString(ts) + } + case nil: + // Be robust against bad transforms. + buf.WriteString("<deleted>") + default: + buf.WriteString(instr.String()) + } + buf.WriteString("\n") + } + } + fmt.Fprintf(buf, "\n") +} + +// newBasicBlock adds to f a new basic block and returns it. It does +// not automatically become the current block for subsequent calls to emit. +// comment is an optional string for more readable debugging output. +// +func (f *Function) newBasicBlock(comment string) *BasicBlock { + b := &BasicBlock{ + Index: len(f.Blocks), + Comment: comment, + parent: f, + } + b.Succs = b.succs2[:0] + f.Blocks = append(f.Blocks, b) + return b +} + +// NewFunction returns a new synthetic Function instance belonging to +// prog, with its name and signature fields set as specified. +// +// The caller is responsible for initializing the remaining fields of +// the function object, e.g. Pkg, Params, Blocks. +// +// It is practically impossible for clients to construct well-formed +// SSA functions/packages/programs directly, so we assume this is the +// job of the Builder alone. NewFunction exists to provide clients a +// little flexibility. For example, analysis tools may wish to +// construct fake Functions for the root of the callgraph, a fake +// "reflect" package, etc. +// +// TODO(adonovan): think harder about the API here. +// +func (prog *Program) NewFunction(name string, sig *types.Signature, provenance string) *Function { + return &Function{Prog: prog, name: name, Signature: sig, Synthetic: provenance} +} + +type extentNode [2]token.Pos + +func (n extentNode) Pos() token.Pos { return n[0] } +func (n extentNode) End() token.Pos { return n[1] } + +// Syntax returns an ast.Node whose Pos/End methods provide the +// lexical extent of the function if it was defined by Go source code +// (f.Synthetic==""), or nil otherwise. +// +// If f was built with debug information (see Package.SetDebugRef), +// the result is the *ast.FuncDecl or *ast.FuncLit that declared the +// function. Otherwise, it is an opaque Node providing only position +// information; this avoids pinning the AST in memory. +// +func (f *Function) Syntax() ast.Node { return f.syntax } diff --git a/vendor/honnef.co/go/tools/ssa/identical.go b/vendor/honnef.co/go/tools/ssa/identical.go new file mode 100644 index 0000000..53cbee1 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/identical.go @@ -0,0 +1,7 @@ +// +build go1.8 + +package ssa + +import "go/types" + +var structTypesIdentical = types.IdenticalIgnoreTags diff --git a/vendor/honnef.co/go/tools/ssa/identical_17.go b/vendor/honnef.co/go/tools/ssa/identical_17.go new file mode 100644 index 0000000..da89d33 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/identical_17.go @@ -0,0 +1,7 @@ +// +build !go1.8 + +package ssa + +import "go/types" + +var structTypesIdentical = types.Identical diff --git a/vendor/honnef.co/go/tools/ssa/lift.go b/vendor/honnef.co/go/tools/ssa/lift.go new file mode 100644 index 0000000..0270797 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/lift.go @@ -0,0 +1,608 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// This file defines the lifting pass which tries to "lift" Alloc +// cells (new/local variables) into SSA registers, replacing loads +// with the dominating stored value, eliminating loads and stores, and +// inserting φ-nodes as needed. + +// Cited papers and resources: +// +// Ron Cytron et al. 1991. Efficiently computing SSA form... +// http://doi.acm.org/10.1145/115372.115320 +// +// Cooper, Harvey, Kennedy. 2001. A Simple, Fast Dominance Algorithm. +// Software Practice and Experience 2001, 4:1-10. +// http://www.hipersoft.rice.edu/grads/publications/dom14.pdf +// +// Daniel Berlin, llvmdev mailing list, 2012. +// http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-January/046638.html +// (Be sure to expand the whole thread.) + +// TODO(adonovan): opt: there are many optimizations worth evaluating, and +// the conventional wisdom for SSA construction is that a simple +// algorithm well engineered often beats those of better asymptotic +// complexity on all but the most egregious inputs. +// +// Danny Berlin suggests that the Cooper et al. algorithm for +// computing the dominance frontier is superior to Cytron et al. +// Furthermore he recommends that rather than computing the DF for the +// whole function then renaming all alloc cells, it may be cheaper to +// compute the DF for each alloc cell separately and throw it away. +// +// Consider exploiting liveness information to avoid creating dead +// φ-nodes which we then immediately remove. +// +// Integrate lifting with scalar replacement of aggregates (SRA) since +// the two are synergistic. +// +// Also see many other "TODO: opt" suggestions in the code. + +import ( + "fmt" + "go/token" + "go/types" + "math/big" + "os" +) + +// If true, perform sanity checking and show diagnostic information at +// each step of lifting. Very verbose. +const debugLifting = false + +// domFrontier maps each block to the set of blocks in its dominance +// frontier. The outer slice is conceptually a map keyed by +// Block.Index. The inner slice is conceptually a set, possibly +// containing duplicates. +// +// TODO(adonovan): opt: measure impact of dups; consider a packed bit +// representation, e.g. big.Int, and bitwise parallel operations for +// the union step in the Children loop. +// +// domFrontier's methods mutate the slice's elements but not its +// length, so their receivers needn't be pointers. +// +type domFrontier [][]*BasicBlock + +func (df domFrontier) add(u, v *BasicBlock) { + p := &df[u.Index] + *p = append(*p, v) +} + +// build builds the dominance frontier df for the dominator (sub)tree +// rooted at u, using the Cytron et al. algorithm. +// +// TODO(adonovan): opt: consider Berlin approach, computing pruned SSA +// by pruning the entire IDF computation, rather than merely pruning +// the DF -> IDF step. +func (df domFrontier) build(u *BasicBlock) { + // Encounter each node u in postorder of dom tree. + for _, child := range u.dom.children { + df.build(child) + } + for _, vb := range u.Succs { + if v := vb.dom; v.idom != u { + df.add(u, vb) + } + } + for _, w := range u.dom.children { + for _, vb := range df[w.Index] { + // TODO(adonovan): opt: use word-parallel bitwise union. + if v := vb.dom; v.idom != u { + df.add(u, vb) + } + } + } +} + +func buildDomFrontier(fn *Function) domFrontier { + df := make(domFrontier, len(fn.Blocks)) + df.build(fn.Blocks[0]) + if fn.Recover != nil { + df.build(fn.Recover) + } + return df +} + +func RemoveInstr(refs []Instruction, instr Instruction) []Instruction { + return removeInstr(refs, instr) +} + +func removeInstr(refs []Instruction, instr Instruction) []Instruction { + i := 0 + for _, ref := range refs { + if ref == instr { + continue + } + refs[i] = ref + i++ + } + for j := i; j != len(refs); j++ { + refs[j] = nil // aid GC + } + return refs[:i] +} + +// lift attempts to replace local and new Allocs accessed only with +// load/store by SSA registers, inserting φ-nodes where necessary. +// The result is a program in classical pruned SSA form. +// +// Preconditions: +// - fn has no dead blocks (blockopt has run). +// - Def/use info (Operands and Referrers) is up-to-date. +// - The dominator tree is up-to-date. +// +func lift(fn *Function) { + // TODO(adonovan): opt: lots of little optimizations may be + // worthwhile here, especially if they cause us to avoid + // buildDomFrontier. For example: + // + // - Alloc never loaded? Eliminate. + // - Alloc never stored? Replace all loads with a zero constant. + // - Alloc stored once? Replace loads with dominating store; + // don't forget that an Alloc is itself an effective store + // of zero. + // - Alloc used only within a single block? + // Use degenerate algorithm avoiding φ-nodes. + // - Consider synergy with scalar replacement of aggregates (SRA). + // e.g. *(&x.f) where x is an Alloc. + // Perhaps we'd get better results if we generated this as x.f + // i.e. Field(x, .f) instead of Load(FieldIndex(x, .f)). + // Unclear. + // + // But we will start with the simplest correct code. + df := buildDomFrontier(fn) + + if debugLifting { + title := false + for i, blocks := range df { + if blocks != nil { + if !title { + fmt.Fprintf(os.Stderr, "Dominance frontier of %s:\n", fn) + title = true + } + fmt.Fprintf(os.Stderr, "\t%s: %s\n", fn.Blocks[i], blocks) + } + } + } + + newPhis := make(newPhiMap) + + // During this pass we will replace some BasicBlock.Instrs + // (allocs, loads and stores) with nil, keeping a count in + // BasicBlock.gaps. At the end we will reset Instrs to the + // concatenation of all non-dead newPhis and non-nil Instrs + // for the block, reusing the original array if space permits. + + // While we're here, we also eliminate 'rundefers' + // instructions in functions that contain no 'defer' + // instructions. + usesDefer := false + + // Determine which allocs we can lift and number them densely. + // The renaming phase uses this numbering for compact maps. + numAllocs := 0 + for _, b := range fn.Blocks { + b.gaps = 0 + b.rundefers = 0 + for _, instr := range b.Instrs { + switch instr := instr.(type) { + case *Alloc: + index := -1 + if liftAlloc(df, instr, newPhis) { + index = numAllocs + numAllocs++ + } + instr.index = index + case *Defer: + usesDefer = true + case *RunDefers: + b.rundefers++ + } + } + } + + // renaming maps an alloc (keyed by index) to its replacement + // value. Initially the renaming contains nil, signifying the + // zero constant of the appropriate type; we construct the + // Const lazily at most once on each path through the domtree. + // TODO(adonovan): opt: cache per-function not per subtree. + renaming := make([]Value, numAllocs) + + // Renaming. + rename(fn.Blocks[0], renaming, newPhis) + + // Eliminate dead new phis, then prepend the live ones to each block. + for _, b := range fn.Blocks { + + // Compress the newPhis slice to eliminate unused phis. + // TODO(adonovan): opt: compute liveness to avoid + // placing phis in blocks for which the alloc cell is + // not live. + nps := newPhis[b] + j := 0 + for _, np := range nps { + if !phiIsLive(np.phi) { + // discard it, first removing it from referrers + for _, newval := range np.phi.Edges { + if refs := newval.Referrers(); refs != nil { + *refs = removeInstr(*refs, np.phi) + } + } + continue + } + nps[j] = np + j++ + } + nps = nps[:j] + + rundefersToKill := b.rundefers + if usesDefer { + rundefersToKill = 0 + } + + if j+b.gaps+rundefersToKill == 0 { + continue // fast path: no new phis or gaps + } + + // Compact nps + non-nil Instrs into a new slice. + // TODO(adonovan): opt: compact in situ if there is + // sufficient space or slack in the slice. + dst := make([]Instruction, len(b.Instrs)+j-b.gaps-rundefersToKill) + for i, np := range nps { + dst[i] = np.phi + } + for _, instr := range b.Instrs { + if instr == nil { + continue + } + if !usesDefer { + if _, ok := instr.(*RunDefers); ok { + continue + } + } + dst[j] = instr + j++ + } + for i, np := range nps { + dst[i] = np.phi + } + b.Instrs = dst + } + + // Remove any fn.Locals that were lifted. + j := 0 + for _, l := range fn.Locals { + if l.index < 0 { + fn.Locals[j] = l + j++ + } + } + // Nil out fn.Locals[j:] to aid GC. + for i := j; i < len(fn.Locals); i++ { + fn.Locals[i] = nil + } + fn.Locals = fn.Locals[:j] +} + +func phiIsLive(phi *Phi) bool { + for _, instr := range *phi.Referrers() { + if instr == phi { + continue // self-refs don't count + } + if _, ok := instr.(*DebugRef); ok { + continue // debug refs don't count + } + return true + } + return false +} + +type blockSet struct{ big.Int } // (inherit methods from Int) + +// add adds b to the set and returns true if the set changed. +func (s *blockSet) add(b *BasicBlock) bool { + i := b.Index + if s.Bit(i) != 0 { + return false + } + s.SetBit(&s.Int, i, 1) + return true +} + +// take removes an arbitrary element from a set s and +// returns its index, or returns -1 if empty. +func (s *blockSet) take() int { + l := s.BitLen() + for i := 0; i < l; i++ { + if s.Bit(i) == 1 { + s.SetBit(&s.Int, i, 0) + return i + } + } + return -1 +} + +// newPhi is a pair of a newly introduced φ-node and the lifted Alloc +// it replaces. +type newPhi struct { + phi *Phi + alloc *Alloc +} + +// newPhiMap records for each basic block, the set of newPhis that +// must be prepended to the block. +type newPhiMap map[*BasicBlock][]newPhi + +// liftAlloc determines whether alloc can be lifted into registers, +// and if so, it populates newPhis with all the φ-nodes it may require +// and returns true. +// +func liftAlloc(df domFrontier, alloc *Alloc, newPhis newPhiMap) bool { + // Don't lift aggregates into registers, because we don't have + // a way to express their zero-constants. + switch deref(alloc.Type()).Underlying().(type) { + case *types.Array, *types.Struct: + return false + } + + // Don't lift named return values in functions that defer + // calls that may recover from panic. + if fn := alloc.Parent(); fn.Recover != nil { + for _, nr := range fn.namedResults { + if nr == alloc { + return false + } + } + } + + // Compute defblocks, the set of blocks containing a + // definition of the alloc cell. + var defblocks blockSet + for _, instr := range *alloc.Referrers() { + // Bail out if we discover the alloc is not liftable; + // the only operations permitted to use the alloc are + // loads/stores into the cell, and DebugRef. + switch instr := instr.(type) { + case *Store: + if instr.Val == alloc { + return false // address used as value + } + if instr.Addr != alloc { + panic("Alloc.Referrers is inconsistent") + } + defblocks.add(instr.Block()) + case *UnOp: + if instr.Op != token.MUL { + return false // not a load + } + if instr.X != alloc { + panic("Alloc.Referrers is inconsistent") + } + case *DebugRef: + // ok + default: + return false // some other instruction + } + } + // The Alloc itself counts as a (zero) definition of the cell. + defblocks.add(alloc.Block()) + + if debugLifting { + fmt.Fprintln(os.Stderr, "\tlifting ", alloc, alloc.Name()) + } + + fn := alloc.Parent() + + // Φ-insertion. + // + // What follows is the body of the main loop of the insert-φ + // function described by Cytron et al, but instead of using + // counter tricks, we just reset the 'hasAlready' and 'work' + // sets each iteration. These are bitmaps so it's pretty cheap. + // + // TODO(adonovan): opt: recycle slice storage for W, + // hasAlready, defBlocks across liftAlloc calls. + var hasAlready blockSet + + // Initialize W and work to defblocks. + var work blockSet = defblocks // blocks seen + var W blockSet // blocks to do + W.Set(&defblocks.Int) + + // Traverse iterated dominance frontier, inserting φ-nodes. + for i := W.take(); i != -1; i = W.take() { + u := fn.Blocks[i] + for _, v := range df[u.Index] { + if hasAlready.add(v) { + // Create φ-node. + // It will be prepended to v.Instrs later, if needed. + phi := &Phi{ + Edges: make([]Value, len(v.Preds)), + Comment: alloc.Comment, + } + phi.pos = alloc.Pos() + phi.setType(deref(alloc.Type())) + phi.block = v + if debugLifting { + fmt.Fprintf(os.Stderr, "\tplace %s = %s at block %s\n", phi.Name(), phi, v) + } + newPhis[v] = append(newPhis[v], newPhi{phi, alloc}) + + if work.add(v) { + W.add(v) + } + } + } + } + + return true +} + +func ReplaceAll(x, y Value) { + replaceAll(x, y) +} + +// replaceAll replaces all intraprocedural uses of x with y, +// updating x.Referrers and y.Referrers. +// Precondition: x.Referrers() != nil, i.e. x must be local to some function. +// +func replaceAll(x, y Value) { + var rands []*Value + pxrefs := x.Referrers() + pyrefs := y.Referrers() + for _, instr := range *pxrefs { + rands = instr.Operands(rands[:0]) // recycle storage + for _, rand := range rands { + if *rand != nil { + if *rand == x { + *rand = y + } + } + } + if pyrefs != nil { + *pyrefs = append(*pyrefs, instr) // dups ok + } + } + *pxrefs = nil // x is now unreferenced +} + +// renamed returns the value to which alloc is being renamed, +// constructing it lazily if it's the implicit zero initialization. +// +func renamed(renaming []Value, alloc *Alloc) Value { + v := renaming[alloc.index] + if v == nil { + v = zeroConst(deref(alloc.Type())) + renaming[alloc.index] = v + } + return v +} + +// rename implements the (Cytron et al) SSA renaming algorithm, a +// preorder traversal of the dominator tree replacing all loads of +// Alloc cells with the value stored to that cell by the dominating +// store instruction. For lifting, we need only consider loads, +// stores and φ-nodes. +// +// renaming is a map from *Alloc (keyed by index number) to its +// dominating stored value; newPhis[x] is the set of new φ-nodes to be +// prepended to block x. +// +func rename(u *BasicBlock, renaming []Value, newPhis newPhiMap) { + // Each φ-node becomes the new name for its associated Alloc. + for _, np := range newPhis[u] { + phi := np.phi + alloc := np.alloc + renaming[alloc.index] = phi + } + + // Rename loads and stores of allocs. + for i, instr := range u.Instrs { + switch instr := instr.(type) { + case *Alloc: + if instr.index >= 0 { // store of zero to Alloc cell + // Replace dominated loads by the zero value. + renaming[instr.index] = nil + if debugLifting { + fmt.Fprintf(os.Stderr, "\tkill alloc %s\n", instr) + } + // Delete the Alloc. + u.Instrs[i] = nil + u.gaps++ + } + + case *Store: + if alloc, ok := instr.Addr.(*Alloc); ok && alloc.index >= 0 { // store to Alloc cell + // Replace dominated loads by the stored value. + renaming[alloc.index] = instr.Val + if debugLifting { + fmt.Fprintf(os.Stderr, "\tkill store %s; new value: %s\n", + instr, instr.Val.Name()) + } + // Remove the store from the referrer list of the stored value. + if refs := instr.Val.Referrers(); refs != nil { + *refs = removeInstr(*refs, instr) + } + // Delete the Store. + u.Instrs[i] = nil + u.gaps++ + } + + case *UnOp: + if instr.Op == token.MUL { + if alloc, ok := instr.X.(*Alloc); ok && alloc.index >= 0 { // load of Alloc cell + newval := renamed(renaming, alloc) + if debugLifting { + fmt.Fprintf(os.Stderr, "\tupdate load %s = %s with %s\n", + instr.Name(), instr, newval.Name()) + } + // Replace all references to + // the loaded value by the + // dominating stored value. + replaceAll(instr, newval) + // Delete the Load. + u.Instrs[i] = nil + u.gaps++ + } + } + + case *DebugRef: + if alloc, ok := instr.X.(*Alloc); ok && alloc.index >= 0 { // ref of Alloc cell + if instr.IsAddr { + instr.X = renamed(renaming, alloc) + instr.IsAddr = false + + // Add DebugRef to instr.X's referrers. + if refs := instr.X.Referrers(); refs != nil { + *refs = append(*refs, instr) + } + } else { + // A source expression denotes the address + // of an Alloc that was optimized away. + instr.X = nil + + // Delete the DebugRef. + u.Instrs[i] = nil + u.gaps++ + } + } + } + } + + // For each φ-node in a CFG successor, rename the edge. + for _, v := range u.Succs { + phis := newPhis[v] + if len(phis) == 0 { + continue + } + i := v.predIndex(u) + for _, np := range phis { + phi := np.phi + alloc := np.alloc + newval := renamed(renaming, alloc) + if debugLifting { + fmt.Fprintf(os.Stderr, "\tsetphi %s edge %s -> %s (#%d) (alloc=%s) := %s\n", + phi.Name(), u, v, i, alloc.Name(), newval.Name()) + } + phi.Edges[i] = newval + if prefs := newval.Referrers(); prefs != nil { + *prefs = append(*prefs, phi) + } + } + } + + // Continue depth-first recursion over domtree, pushing a + // fresh copy of the renaming map for each subtree. + for _, v := range u.dom.children { + // TODO(adonovan): opt: avoid copy on final iteration; use destructive update. + r := make([]Value, len(renaming)) + copy(r, renaming) + rename(v, r, newPhis) + } +} diff --git a/vendor/honnef.co/go/tools/ssa/lvalue.go b/vendor/honnef.co/go/tools/ssa/lvalue.go new file mode 100644 index 0000000..d2226a9 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/lvalue.go @@ -0,0 +1,125 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// lvalues are the union of addressable expressions and map-index +// expressions. + +import ( + "go/ast" + "go/token" + "go/types" +) + +// An lvalue represents an assignable location that may appear on the +// left-hand side of an assignment. This is a generalization of a +// pointer to permit updates to elements of maps. +// +type lvalue interface { + store(fn *Function, v Value) // stores v into the location + load(fn *Function) Value // loads the contents of the location + address(fn *Function) Value // address of the location + typ() types.Type // returns the type of the location +} + +// An address is an lvalue represented by a true pointer. +type address struct { + addr Value + pos token.Pos // source position + expr ast.Expr // source syntax of the value (not address) [debug mode] +} + +func (a *address) load(fn *Function) Value { + load := emitLoad(fn, a.addr) + load.pos = a.pos + return load +} + +func (a *address) store(fn *Function, v Value) { + store := emitStore(fn, a.addr, v, a.pos) + if a.expr != nil { + // store.Val is v, converted for assignability. + emitDebugRef(fn, a.expr, store.Val, false) + } +} + +func (a *address) address(fn *Function) Value { + if a.expr != nil { + emitDebugRef(fn, a.expr, a.addr, true) + } + return a.addr +} + +func (a *address) typ() types.Type { + return deref(a.addr.Type()) +} + +// An element is an lvalue represented by m[k], the location of an +// element of a map or string. These locations are not addressable +// since pointers cannot be formed from them, but they do support +// load(), and in the case of maps, store(). +// +type element struct { + m, k Value // map or string + t types.Type // map element type or string byte type + pos token.Pos // source position of colon ({k:v}) or lbrack (m[k]=v) +} + +func (e *element) load(fn *Function) Value { + l := &Lookup{ + X: e.m, + Index: e.k, + } + l.setPos(e.pos) + l.setType(e.t) + return fn.emit(l) +} + +func (e *element) store(fn *Function, v Value) { + up := &MapUpdate{ + Map: e.m, + Key: e.k, + Value: emitConv(fn, v, e.t), + } + up.pos = e.pos + fn.emit(up) +} + +func (e *element) address(fn *Function) Value { + panic("map/string elements are not addressable") +} + +func (e *element) typ() types.Type { + return e.t +} + +// A blank is a dummy variable whose name is "_". +// It is not reified: loads are illegal and stores are ignored. +// +type blank struct{} + +func (bl blank) load(fn *Function) Value { + panic("blank.load is illegal") +} + +func (bl blank) store(fn *Function, v Value) { + s := &BlankStore{ + Val: v, + } + fn.emit(s) +} + +func (bl blank) address(fn *Function) Value { + panic("blank var is not addressable") +} + +func (bl blank) typ() types.Type { + // This should be the type of the blank Ident; the typechecker + // doesn't provide this yet, but fortunately, we don't need it + // yet either. + panic("blank.typ is unimplemented") +} diff --git a/vendor/honnef.co/go/tools/ssa/methods.go b/vendor/honnef.co/go/tools/ssa/methods.go new file mode 100644 index 0000000..7d1fb42 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/methods.go @@ -0,0 +1,241 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// This file defines utilities for population of method sets. + +import ( + "fmt" + "go/types" +) + +// MethodValue returns the Function implementing method sel, building +// wrapper methods on demand. It returns nil if sel denotes an +// abstract (interface) method. +// +// Precondition: sel.Kind() == MethodVal. +// +// Thread-safe. +// +// EXCLUSIVE_LOCKS_ACQUIRED(prog.methodsMu) +// +func (prog *Program) MethodValue(sel *types.Selection) *Function { + if sel.Kind() != types.MethodVal { + panic(fmt.Sprintf("Method(%s) kind != MethodVal", sel)) + } + T := sel.Recv() + if isInterface(T) { + return nil // abstract method + } + if prog.mode&LogSource != 0 { + defer logStack("Method %s %v", T, sel)() + } + + prog.methodsMu.Lock() + defer prog.methodsMu.Unlock() + + return prog.addMethod(prog.createMethodSet(T), sel) +} + +// LookupMethod returns the implementation of the method of type T +// identified by (pkg, name). It returns nil if the method exists but +// is abstract, and panics if T has no such method. +// +func (prog *Program) LookupMethod(T types.Type, pkg *types.Package, name string) *Function { + sel := prog.MethodSets.MethodSet(T).Lookup(pkg, name) + if sel == nil { + panic(fmt.Sprintf("%s has no method %s", T, types.Id(pkg, name))) + } + return prog.MethodValue(sel) +} + +// methodSet contains the (concrete) methods of a non-interface type. +type methodSet struct { + mapping map[string]*Function // populated lazily + complete bool // mapping contains all methods +} + +// Precondition: !isInterface(T). +// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu) +func (prog *Program) createMethodSet(T types.Type) *methodSet { + mset, ok := prog.methodSets.At(T).(*methodSet) + if !ok { + mset = &methodSet{mapping: make(map[string]*Function)} + prog.methodSets.Set(T, mset) + } + return mset +} + +// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu) +func (prog *Program) addMethod(mset *methodSet, sel *types.Selection) *Function { + if sel.Kind() == types.MethodExpr { + panic(sel) + } + id := sel.Obj().Id() + fn := mset.mapping[id] + if fn == nil { + obj := sel.Obj().(*types.Func) + + needsPromotion := len(sel.Index()) > 1 + needsIndirection := !isPointer(recvType(obj)) && isPointer(sel.Recv()) + if needsPromotion || needsIndirection { + fn = makeWrapper(prog, sel) + } else { + fn = prog.declaredFunc(obj) + } + if fn.Signature.Recv() == nil { + panic(fn) // missing receiver + } + mset.mapping[id] = fn + } + return fn +} + +// RuntimeTypes returns a new unordered slice containing all +// concrete types in the program for which a complete (non-empty) +// method set is required at run-time. +// +// Thread-safe. +// +// EXCLUSIVE_LOCKS_ACQUIRED(prog.methodsMu) +// +func (prog *Program) RuntimeTypes() []types.Type { + prog.methodsMu.Lock() + defer prog.methodsMu.Unlock() + + var res []types.Type + prog.methodSets.Iterate(func(T types.Type, v interface{}) { + if v.(*methodSet).complete { + res = append(res, T) + } + }) + return res +} + +// declaredFunc returns the concrete function/method denoted by obj. +// Panic ensues if there is none. +// +func (prog *Program) declaredFunc(obj *types.Func) *Function { + if v := prog.packageLevelValue(obj); v != nil { + return v.(*Function) + } + panic("no concrete method: " + obj.String()) +} + +// needMethodsOf ensures that runtime type information (including the +// complete method set) is available for the specified type T and all +// its subcomponents. +// +// needMethodsOf must be called for at least every type that is an +// operand of some MakeInterface instruction, and for the type of +// every exported package member. +// +// Precondition: T is not a method signature (*Signature with Recv()!=nil). +// +// Thread-safe. (Called via emitConv from multiple builder goroutines.) +// +// TODO(adonovan): make this faster. It accounts for 20% of SSA build time. +// +// EXCLUSIVE_LOCKS_ACQUIRED(prog.methodsMu) +// +func (prog *Program) needMethodsOf(T types.Type) { + prog.methodsMu.Lock() + prog.needMethods(T, false) + prog.methodsMu.Unlock() +} + +// Precondition: T is not a method signature (*Signature with Recv()!=nil). +// Recursive case: skip => don't create methods for T. +// +// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu) +// +func (prog *Program) needMethods(T types.Type, skip bool) { + // Each package maintains its own set of types it has visited. + if prevSkip, ok := prog.runtimeTypes.At(T).(bool); ok { + // needMethods(T) was previously called + if !prevSkip || skip { + return // already seen, with same or false 'skip' value + } + } + prog.runtimeTypes.Set(T, skip) + + tmset := prog.MethodSets.MethodSet(T) + + if !skip && !isInterface(T) && tmset.Len() > 0 { + // Create methods of T. + mset := prog.createMethodSet(T) + if !mset.complete { + mset.complete = true + n := tmset.Len() + for i := 0; i < n; i++ { + prog.addMethod(mset, tmset.At(i)) + } + } + } + + // Recursion over signatures of each method. + for i := 0; i < tmset.Len(); i++ { + sig := tmset.At(i).Type().(*types.Signature) + prog.needMethods(sig.Params(), false) + prog.needMethods(sig.Results(), false) + } + + switch t := T.(type) { + case *types.Basic: + // nop + + case *types.Interface: + // nop---handled by recursion over method set. + + case *types.Pointer: + prog.needMethods(t.Elem(), false) + + case *types.Slice: + prog.needMethods(t.Elem(), false) + + case *types.Chan: + prog.needMethods(t.Elem(), false) + + case *types.Map: + prog.needMethods(t.Key(), false) + prog.needMethods(t.Elem(), false) + + case *types.Signature: + if t.Recv() != nil { + panic(fmt.Sprintf("Signature %s has Recv %s", t, t.Recv())) + } + prog.needMethods(t.Params(), false) + prog.needMethods(t.Results(), false) + + case *types.Named: + // A pointer-to-named type can be derived from a named + // type via reflection. It may have methods too. + prog.needMethods(types.NewPointer(T), false) + + // Consider 'type T struct{S}' where S has methods. + // Reflection provides no way to get from T to struct{S}, + // only to S, so the method set of struct{S} is unwanted, + // so set 'skip' flag during recursion. + prog.needMethods(t.Underlying(), true) + + case *types.Array: + prog.needMethods(t.Elem(), false) + + case *types.Struct: + for i, n := 0, t.NumFields(); i < n; i++ { + prog.needMethods(t.Field(i).Type(), false) + } + + case *types.Tuple: + for i, n := 0, t.Len(); i < n; i++ { + prog.needMethods(t.At(i).Type(), false) + } + + default: + panic(T) + } +} diff --git a/vendor/honnef.co/go/tools/ssa/mode.go b/vendor/honnef.co/go/tools/ssa/mode.go new file mode 100644 index 0000000..d2a2698 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/mode.go @@ -0,0 +1,100 @@ +// Copyright 2015 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssa + +// This file defines the BuilderMode type and its command-line flag. + +import ( + "bytes" + "fmt" +) + +// BuilderMode is a bitmask of options for diagnostics and checking. +// +// *BuilderMode satisfies the flag.Value interface. Example: +// +// var mode = ssa.BuilderMode(0) +// func init() { flag.Var(&mode, "build", ssa.BuilderModeDoc) } +// +type BuilderMode uint + +const ( + PrintPackages BuilderMode = 1 << iota // Print package inventory to stdout + PrintFunctions // Print function SSA code to stdout + LogSource // Log source locations as SSA builder progresses + SanityCheckFunctions // Perform sanity checking of function bodies + NaiveForm // Build naïve SSA form: don't replace local loads/stores with registers + BuildSerially // Build packages serially, not in parallel. + GlobalDebug // Enable debug info for all packages + BareInits // Build init functions without guards or calls to dependent inits +) + +const BuilderModeDoc = `Options controlling the SSA builder. +The value is a sequence of zero or more of these letters: +C perform sanity [C]hecking of the SSA form. +D include [D]ebug info for every function. +P print [P]ackage inventory. +F print [F]unction SSA code. +S log [S]ource locations as SSA builder progresses. +L build distinct packages seria[L]ly instead of in parallel. +N build [N]aive SSA form: don't replace local loads/stores with registers. +I build bare [I]nit functions: no init guards or calls to dependent inits. +` + +func (m BuilderMode) String() string { + var buf bytes.Buffer + if m&GlobalDebug != 0 { + buf.WriteByte('D') + } + if m&PrintPackages != 0 { + buf.WriteByte('P') + } + if m&PrintFunctions != 0 { + buf.WriteByte('F') + } + if m&LogSource != 0 { + buf.WriteByte('S') + } + if m&SanityCheckFunctions != 0 { + buf.WriteByte('C') + } + if m&NaiveForm != 0 { + buf.WriteByte('N') + } + if m&BuildSerially != 0 { + buf.WriteByte('L') + } + return buf.String() +} + +// Set parses the flag characters in s and updates *m. +func (m *BuilderMode) Set(s string) error { + var mode BuilderMode + for _, c := range s { + switch c { + case 'D': + mode |= GlobalDebug + case 'P': + mode |= PrintPackages + case 'F': + mode |= PrintFunctions + case 'S': + mode |= LogSource | BuildSerially + case 'C': + mode |= SanityCheckFunctions + case 'N': + mode |= NaiveForm + case 'L': + mode |= BuildSerially + default: + return fmt.Errorf("unknown BuilderMode option: %q", c) + } + } + *m = mode + return nil +} + +// Get returns m. +func (m BuilderMode) Get() interface{} { return m } diff --git a/vendor/honnef.co/go/tools/ssa/print.go b/vendor/honnef.co/go/tools/ssa/print.go new file mode 100644 index 0000000..a7deb88 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/print.go @@ -0,0 +1,433 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// This file implements the String() methods for all Value and +// Instruction types. + +import ( + "bytes" + "fmt" + "go/types" + "io" + "reflect" + "sort" + + "golang.org/x/tools/go/types/typeutil" +) + +// relName returns the name of v relative to i. +// In most cases, this is identical to v.Name(), but references to +// Functions (including methods) and Globals use RelString and +// all types are displayed with relType, so that only cross-package +// references are package-qualified. +// +func relName(v Value, i Instruction) string { + var from *types.Package + if i != nil { + from = i.Parent().pkg() + } + switch v := v.(type) { + case Member: // *Function or *Global + return v.RelString(from) + case *Const: + return v.RelString(from) + } + return v.Name() +} + +func relType(t types.Type, from *types.Package) string { + return types.TypeString(t, types.RelativeTo(from)) +} + +func relString(m Member, from *types.Package) string { + // NB: not all globals have an Object (e.g. init$guard), + // so use Package().Object not Object.Package(). + if pkg := m.Package().Pkg; pkg != nil && pkg != from { + return fmt.Sprintf("%s.%s", pkg.Path(), m.Name()) + } + return m.Name() +} + +// Value.String() +// +// This method is provided only for debugging. +// It never appears in disassembly, which uses Value.Name(). + +func (v *Parameter) String() string { + from := v.Parent().pkg() + return fmt.Sprintf("parameter %s : %s", v.Name(), relType(v.Type(), from)) +} + +func (v *FreeVar) String() string { + from := v.Parent().pkg() + return fmt.Sprintf("freevar %s : %s", v.Name(), relType(v.Type(), from)) +} + +func (v *Builtin) String() string { + return fmt.Sprintf("builtin %s", v.Name()) +} + +// Instruction.String() + +func (v *Alloc) String() string { + op := "local" + if v.Heap { + op = "new" + } + from := v.Parent().pkg() + return fmt.Sprintf("%s %s (%s)", op, relType(deref(v.Type()), from), v.Comment) +} + +func (v *Phi) String() string { + var b bytes.Buffer + b.WriteString("φ [") + for i, edge := range v.Edges { + if i > 0 { + b.WriteString(", ") + } + // Be robust against malformed CFG. + block := -1 + if v.block != nil && i < len(v.block.Preds) { + block = v.block.Preds[i].Index + } + fmt.Fprintf(&b, "%d: ", block) + edgeVal := "<nil>" // be robust + if edge != nil { + edgeVal = relName(edge, v) + } + b.WriteString(edgeVal) + } + b.WriteString("]") + if v.Comment != "" { + b.WriteString(" #") + b.WriteString(v.Comment) + } + return b.String() +} + +func printCall(v *CallCommon, prefix string, instr Instruction) string { + var b bytes.Buffer + b.WriteString(prefix) + if !v.IsInvoke() { + b.WriteString(relName(v.Value, instr)) + } else { + fmt.Fprintf(&b, "invoke %s.%s", relName(v.Value, instr), v.Method.Name()) + } + b.WriteString("(") + for i, arg := range v.Args { + if i > 0 { + b.WriteString(", ") + } + b.WriteString(relName(arg, instr)) + } + if v.Signature().Variadic() { + b.WriteString("...") + } + b.WriteString(")") + return b.String() +} + +func (c *CallCommon) String() string { + return printCall(c, "", nil) +} + +func (v *Call) String() string { + return printCall(&v.Call, "", v) +} + +func (v *BinOp) String() string { + return fmt.Sprintf("%s %s %s", relName(v.X, v), v.Op.String(), relName(v.Y, v)) +} + +func (v *UnOp) String() string { + return fmt.Sprintf("%s%s%s", v.Op, relName(v.X, v), commaOk(v.CommaOk)) +} + +func printConv(prefix string, v, x Value) string { + from := v.Parent().pkg() + return fmt.Sprintf("%s %s <- %s (%s)", + prefix, + relType(v.Type(), from), + relType(x.Type(), from), + relName(x, v.(Instruction))) +} + +func (v *ChangeType) String() string { return printConv("changetype", v, v.X) } +func (v *Convert) String() string { return printConv("convert", v, v.X) } +func (v *ChangeInterface) String() string { return printConv("change interface", v, v.X) } +func (v *MakeInterface) String() string { return printConv("make", v, v.X) } + +func (v *MakeClosure) String() string { + var b bytes.Buffer + fmt.Fprintf(&b, "make closure %s", relName(v.Fn, v)) + if v.Bindings != nil { + b.WriteString(" [") + for i, c := range v.Bindings { + if i > 0 { + b.WriteString(", ") + } + b.WriteString(relName(c, v)) + } + b.WriteString("]") + } + return b.String() +} + +func (v *MakeSlice) String() string { + from := v.Parent().pkg() + return fmt.Sprintf("make %s %s %s", + relType(v.Type(), from), + relName(v.Len, v), + relName(v.Cap, v)) +} + +func (v *Slice) String() string { + var b bytes.Buffer + b.WriteString("slice ") + b.WriteString(relName(v.X, v)) + b.WriteString("[") + if v.Low != nil { + b.WriteString(relName(v.Low, v)) + } + b.WriteString(":") + if v.High != nil { + b.WriteString(relName(v.High, v)) + } + if v.Max != nil { + b.WriteString(":") + b.WriteString(relName(v.Max, v)) + } + b.WriteString("]") + return b.String() +} + +func (v *MakeMap) String() string { + res := "" + if v.Reserve != nil { + res = relName(v.Reserve, v) + } + from := v.Parent().pkg() + return fmt.Sprintf("make %s %s", relType(v.Type(), from), res) +} + +func (v *MakeChan) String() string { + from := v.Parent().pkg() + return fmt.Sprintf("make %s %s", relType(v.Type(), from), relName(v.Size, v)) +} + +func (v *FieldAddr) String() string { + st := deref(v.X.Type()).Underlying().(*types.Struct) + // Be robust against a bad index. + name := "?" + if 0 <= v.Field && v.Field < st.NumFields() { + name = st.Field(v.Field).Name() + } + return fmt.Sprintf("&%s.%s [#%d]", relName(v.X, v), name, v.Field) +} + +func (v *Field) String() string { + st := v.X.Type().Underlying().(*types.Struct) + // Be robust against a bad index. + name := "?" + if 0 <= v.Field && v.Field < st.NumFields() { + name = st.Field(v.Field).Name() + } + return fmt.Sprintf("%s.%s [#%d]", relName(v.X, v), name, v.Field) +} + +func (v *IndexAddr) String() string { + return fmt.Sprintf("&%s[%s]", relName(v.X, v), relName(v.Index, v)) +} + +func (v *Index) String() string { + return fmt.Sprintf("%s[%s]", relName(v.X, v), relName(v.Index, v)) +} + +func (v *Lookup) String() string { + return fmt.Sprintf("%s[%s]%s", relName(v.X, v), relName(v.Index, v), commaOk(v.CommaOk)) +} + +func (v *Range) String() string { + return "range " + relName(v.X, v) +} + +func (v *Next) String() string { + return "next " + relName(v.Iter, v) +} + +func (v *TypeAssert) String() string { + from := v.Parent().pkg() + return fmt.Sprintf("typeassert%s %s.(%s)", commaOk(v.CommaOk), relName(v.X, v), relType(v.AssertedType, from)) +} + +func (v *Extract) String() string { + return fmt.Sprintf("extract %s #%d", relName(v.Tuple, v), v.Index) +} + +func (s *Jump) String() string { + // Be robust against malformed CFG. + block := -1 + if s.block != nil && len(s.block.Succs) == 1 { + block = s.block.Succs[0].Index + } + return fmt.Sprintf("jump %d", block) +} + +func (s *If) String() string { + // Be robust against malformed CFG. + tblock, fblock := -1, -1 + if s.block != nil && len(s.block.Succs) == 2 { + tblock = s.block.Succs[0].Index + fblock = s.block.Succs[1].Index + } + return fmt.Sprintf("if %s goto %d else %d", relName(s.Cond, s), tblock, fblock) +} + +func (s *Go) String() string { + return printCall(&s.Call, "go ", s) +} + +func (s *Panic) String() string { + return "panic " + relName(s.X, s) +} + +func (s *Return) String() string { + var b bytes.Buffer + b.WriteString("return") + for i, r := range s.Results { + if i == 0 { + b.WriteString(" ") + } else { + b.WriteString(", ") + } + b.WriteString(relName(r, s)) + } + return b.String() +} + +func (*RunDefers) String() string { + return "rundefers" +} + +func (s *Send) String() string { + return fmt.Sprintf("send %s <- %s", relName(s.Chan, s), relName(s.X, s)) +} + +func (s *Defer) String() string { + return printCall(&s.Call, "defer ", s) +} + +func (s *Select) String() string { + var b bytes.Buffer + for i, st := range s.States { + if i > 0 { + b.WriteString(", ") + } + if st.Dir == types.RecvOnly { + b.WriteString("<-") + b.WriteString(relName(st.Chan, s)) + } else { + b.WriteString(relName(st.Chan, s)) + b.WriteString("<-") + b.WriteString(relName(st.Send, s)) + } + } + non := "" + if !s.Blocking { + non = "non" + } + return fmt.Sprintf("select %sblocking [%s]", non, b.String()) +} + +func (s *Store) String() string { + return fmt.Sprintf("*%s = %s", relName(s.Addr, s), relName(s.Val, s)) +} + +func (s *BlankStore) String() string { + return fmt.Sprintf("_ = %s", relName(s.Val, s)) +} + +func (s *MapUpdate) String() string { + return fmt.Sprintf("%s[%s] = %s", relName(s.Map, s), relName(s.Key, s), relName(s.Value, s)) +} + +func (s *DebugRef) String() string { + p := s.Parent().Prog.Fset.Position(s.Pos()) + var descr interface{} + if s.object != nil { + descr = s.object // e.g. "var x int" + } else { + descr = reflect.TypeOf(s.Expr) // e.g. "*ast.CallExpr" + } + var addr string + if s.IsAddr { + addr = "address of " + } + return fmt.Sprintf("; %s%s @ %d:%d is %s", addr, descr, p.Line, p.Column, s.X.Name()) +} + +func (p *Package) String() string { + return "package " + p.Pkg.Path() +} + +var _ io.WriterTo = (*Package)(nil) // *Package implements io.Writer + +func (p *Package) WriteTo(w io.Writer) (int64, error) { + var buf bytes.Buffer + WritePackage(&buf, p) + n, err := w.Write(buf.Bytes()) + return int64(n), err +} + +// WritePackage writes to buf a human-readable summary of p. +func WritePackage(buf *bytes.Buffer, p *Package) { + fmt.Fprintf(buf, "%s:\n", p) + + var names []string + maxname := 0 + for name := range p.Members { + if l := len(name); l > maxname { + maxname = l + } + names = append(names, name) + } + + from := p.Pkg + sort.Strings(names) + for _, name := range names { + switch mem := p.Members[name].(type) { + case *NamedConst: + fmt.Fprintf(buf, " const %-*s %s = %s\n", + maxname, name, mem.Name(), mem.Value.RelString(from)) + + case *Function: + fmt.Fprintf(buf, " func %-*s %s\n", + maxname, name, relType(mem.Type(), from)) + + case *Type: + fmt.Fprintf(buf, " type %-*s %s\n", + maxname, name, relType(mem.Type().Underlying(), from)) + for _, meth := range typeutil.IntuitiveMethodSet(mem.Type(), &p.Prog.MethodSets) { + fmt.Fprintf(buf, " %s\n", types.SelectionString(meth, types.RelativeTo(from))) + } + + case *Global: + fmt.Fprintf(buf, " var %-*s %s\n", + maxname, name, relType(mem.Type().(*types.Pointer).Elem(), from)) + } + } + + fmt.Fprintf(buf, "\n") +} + +func commaOk(x bool) string { + if x { + return ",ok" + } + return "" +} diff --git a/vendor/honnef.co/go/tools/ssa/sanity.go b/vendor/honnef.co/go/tools/ssa/sanity.go new file mode 100644 index 0000000..bd7377c --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/sanity.go @@ -0,0 +1,523 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// An optional pass for sanity-checking invariants of the SSA representation. +// Currently it checks CFG invariants but little at the instruction level. + +import ( + "fmt" + "go/types" + "io" + "os" + "strings" +) + +type sanity struct { + reporter io.Writer + fn *Function + block *BasicBlock + instrs map[Instruction]struct{} + insane bool +} + +// sanityCheck performs integrity checking of the SSA representation +// of the function fn and returns true if it was valid. Diagnostics +// are written to reporter if non-nil, os.Stderr otherwise. Some +// diagnostics are only warnings and do not imply a negative result. +// +// Sanity-checking is intended to facilitate the debugging of code +// transformation passes. +// +func sanityCheck(fn *Function, reporter io.Writer) bool { + if reporter == nil { + reporter = os.Stderr + } + return (&sanity{reporter: reporter}).checkFunction(fn) +} + +// mustSanityCheck is like sanityCheck but panics instead of returning +// a negative result. +// +func mustSanityCheck(fn *Function, reporter io.Writer) { + if !sanityCheck(fn, reporter) { + fn.WriteTo(os.Stderr) + panic("SanityCheck failed") + } +} + +func (s *sanity) diagnostic(prefix, format string, args ...interface{}) { + fmt.Fprintf(s.reporter, "%s: function %s", prefix, s.fn) + if s.block != nil { + fmt.Fprintf(s.reporter, ", block %s", s.block) + } + io.WriteString(s.reporter, ": ") + fmt.Fprintf(s.reporter, format, args...) + io.WriteString(s.reporter, "\n") +} + +func (s *sanity) errorf(format string, args ...interface{}) { + s.insane = true + s.diagnostic("Error", format, args...) +} + +func (s *sanity) warnf(format string, args ...interface{}) { + s.diagnostic("Warning", format, args...) +} + +// findDuplicate returns an arbitrary basic block that appeared more +// than once in blocks, or nil if all were unique. +func findDuplicate(blocks []*BasicBlock) *BasicBlock { + if len(blocks) < 2 { + return nil + } + if blocks[0] == blocks[1] { + return blocks[0] + } + // Slow path: + m := make(map[*BasicBlock]bool) + for _, b := range blocks { + if m[b] { + return b + } + m[b] = true + } + return nil +} + +func (s *sanity) checkInstr(idx int, instr Instruction) { + switch instr := instr.(type) { + case *If, *Jump, *Return, *Panic: + s.errorf("control flow instruction not at end of block") + case *Phi: + if idx == 0 { + // It suffices to apply this check to just the first phi node. + if dup := findDuplicate(s.block.Preds); dup != nil { + s.errorf("phi node in block with duplicate predecessor %s", dup) + } + } else { + prev := s.block.Instrs[idx-1] + if _, ok := prev.(*Phi); !ok { + s.errorf("Phi instruction follows a non-Phi: %T", prev) + } + } + if ne, np := len(instr.Edges), len(s.block.Preds); ne != np { + s.errorf("phi node has %d edges but %d predecessors", ne, np) + + } else { + for i, e := range instr.Edges { + if e == nil { + s.errorf("phi node '%s' has no value for edge #%d from %s", instr.Comment, i, s.block.Preds[i]) + } + } + } + + case *Alloc: + if !instr.Heap { + found := false + for _, l := range s.fn.Locals { + if l == instr { + found = true + break + } + } + if !found { + s.errorf("local alloc %s = %s does not appear in Function.Locals", instr.Name(), instr) + } + } + + case *BinOp: + case *Call: + case *ChangeInterface: + case *ChangeType: + case *Convert: + if _, ok := instr.X.Type().Underlying().(*types.Basic); !ok { + if _, ok := instr.Type().Underlying().(*types.Basic); !ok { + s.errorf("convert %s -> %s: at least one type must be basic", instr.X.Type(), instr.Type()) + } + } + + case *Defer: + case *Extract: + case *Field: + case *FieldAddr: + case *Go: + case *Index: + case *IndexAddr: + case *Lookup: + case *MakeChan: + case *MakeClosure: + numFree := len(instr.Fn.(*Function).FreeVars) + numBind := len(instr.Bindings) + if numFree != numBind { + s.errorf("MakeClosure has %d Bindings for function %s with %d free vars", + numBind, instr.Fn, numFree) + + } + if recv := instr.Type().(*types.Signature).Recv(); recv != nil { + s.errorf("MakeClosure's type includes receiver %s", recv.Type()) + } + + case *MakeInterface: + case *MakeMap: + case *MakeSlice: + case *MapUpdate: + case *Next: + case *Range: + case *RunDefers: + case *Select: + case *Send: + case *Slice: + case *Store: + case *TypeAssert: + case *UnOp: + case *DebugRef: + case *BlankStore: + case *Sigma: + // TODO(adonovan): implement checks. + default: + panic(fmt.Sprintf("Unknown instruction type: %T", instr)) + } + + if call, ok := instr.(CallInstruction); ok { + if call.Common().Signature() == nil { + s.errorf("nil signature: %s", call) + } + } + + // Check that value-defining instructions have valid types + // and a valid referrer list. + if v, ok := instr.(Value); ok { + t := v.Type() + if t == nil { + s.errorf("no type: %s = %s", v.Name(), v) + } else if t == tRangeIter { + // not a proper type; ignore. + } else if b, ok := t.Underlying().(*types.Basic); ok && b.Info()&types.IsUntyped != 0 { + s.errorf("instruction has 'untyped' result: %s = %s : %s", v.Name(), v, t) + } + s.checkReferrerList(v) + } + + // Untyped constants are legal as instruction Operands(), + // for example: + // _ = "foo"[0] + // or: + // if wordsize==64 {...} + + // All other non-Instruction Values can be found via their + // enclosing Function or Package. +} + +func (s *sanity) checkFinalInstr(idx int, instr Instruction) { + switch instr := instr.(type) { + case *If: + if nsuccs := len(s.block.Succs); nsuccs != 2 { + s.errorf("If-terminated block has %d successors; expected 2", nsuccs) + return + } + if s.block.Succs[0] == s.block.Succs[1] { + s.errorf("If-instruction has same True, False target blocks: %s", s.block.Succs[0]) + return + } + + case *Jump: + if nsuccs := len(s.block.Succs); nsuccs != 1 { + s.errorf("Jump-terminated block has %d successors; expected 1", nsuccs) + return + } + + case *Return: + if nsuccs := len(s.block.Succs); nsuccs != 0 { + s.errorf("Return-terminated block has %d successors; expected none", nsuccs) + return + } + if na, nf := len(instr.Results), s.fn.Signature.Results().Len(); nf != na { + s.errorf("%d-ary return in %d-ary function", na, nf) + } + + case *Panic: + if nsuccs := len(s.block.Succs); nsuccs != 0 { + s.errorf("Panic-terminated block has %d successors; expected none", nsuccs) + return + } + + default: + s.errorf("non-control flow instruction at end of block") + } +} + +func (s *sanity) checkBlock(b *BasicBlock, index int) { + s.block = b + + if b.Index != index { + s.errorf("block has incorrect Index %d", b.Index) + } + if b.parent != s.fn { + s.errorf("block has incorrect parent %s", b.parent) + } + + // Check all blocks are reachable. + // (The entry block is always implicitly reachable, + // as is the Recover block, if any.) + if (index > 0 && b != b.parent.Recover) && len(b.Preds) == 0 { + s.warnf("unreachable block") + if b.Instrs == nil { + // Since this block is about to be pruned, + // tolerating transient problems in it + // simplifies other optimizations. + return + } + } + + // Check predecessor and successor relations are dual, + // and that all blocks in CFG belong to same function. + for _, a := range b.Preds { + found := false + for _, bb := range a.Succs { + if bb == b { + found = true + break + } + } + if !found { + s.errorf("expected successor edge in predecessor %s; found only: %s", a, a.Succs) + } + if a.parent != s.fn { + s.errorf("predecessor %s belongs to different function %s", a, a.parent) + } + } + for _, c := range b.Succs { + found := false + for _, bb := range c.Preds { + if bb == b { + found = true + break + } + } + if !found { + s.errorf("expected predecessor edge in successor %s; found only: %s", c, c.Preds) + } + if c.parent != s.fn { + s.errorf("successor %s belongs to different function %s", c, c.parent) + } + } + + // Check each instruction is sane. + n := len(b.Instrs) + if n == 0 { + s.errorf("basic block contains no instructions") + } + var rands [10]*Value // reuse storage + for j, instr := range b.Instrs { + if instr == nil { + s.errorf("nil instruction at index %d", j) + continue + } + if b2 := instr.Block(); b2 == nil { + s.errorf("nil Block() for instruction at index %d", j) + continue + } else if b2 != b { + s.errorf("wrong Block() (%s) for instruction at index %d ", b2, j) + continue + } + if j < n-1 { + s.checkInstr(j, instr) + } else { + s.checkFinalInstr(j, instr) + } + + // Check Instruction.Operands. + operands: + for i, op := range instr.Operands(rands[:0]) { + if op == nil { + s.errorf("nil operand pointer %d of %s", i, instr) + continue + } + val := *op + if val == nil { + continue // a nil operand is ok + } + + // Check that "untyped" types only appear on constant operands. + if _, ok := (*op).(*Const); !ok { + if basic, ok := (*op).Type().(*types.Basic); ok { + if basic.Info()&types.IsUntyped != 0 { + s.errorf("operand #%d of %s is untyped: %s", i, instr, basic) + } + } + } + + // Check that Operands that are also Instructions belong to same function. + // TODO(adonovan): also check their block dominates block b. + if val, ok := val.(Instruction); ok { + if val.Parent() != s.fn { + s.errorf("operand %d of %s is an instruction (%s) from function %s", i, instr, val, val.Parent()) + } + } + + // Check that each function-local operand of + // instr refers back to instr. (NB: quadratic) + switch val := val.(type) { + case *Const, *Global, *Builtin: + continue // not local + case *Function: + if val.parent == nil { + continue // only anon functions are local + } + } + + // TODO(adonovan): check val.Parent() != nil <=> val.Referrers() is defined. + + if refs := val.Referrers(); refs != nil { + for _, ref := range *refs { + if ref == instr { + continue operands + } + } + s.errorf("operand %d of %s (%s) does not refer to us", i, instr, val) + } else { + s.errorf("operand %d of %s (%s) has no referrers", i, instr, val) + } + } + } +} + +func (s *sanity) checkReferrerList(v Value) { + refs := v.Referrers() + if refs == nil { + s.errorf("%s has missing referrer list", v.Name()) + return + } + for i, ref := range *refs { + if _, ok := s.instrs[ref]; !ok { + s.errorf("%s.Referrers()[%d] = %s is not an instruction belonging to this function", v.Name(), i, ref) + } + } +} + +func (s *sanity) checkFunction(fn *Function) bool { + // TODO(adonovan): check Function invariants: + // - check params match signature + // - check transient fields are nil + // - warn if any fn.Locals do not appear among block instructions. + s.fn = fn + if fn.Prog == nil { + s.errorf("nil Prog") + } + + fn.String() // must not crash + fn.RelString(fn.pkg()) // must not crash + + // All functions have a package, except delegates (which are + // shared across packages, or duplicated as weak symbols in a + // separate-compilation model), and error.Error. + if fn.Pkg == nil { + if strings.HasPrefix(fn.Synthetic, "wrapper ") || + strings.HasPrefix(fn.Synthetic, "bound ") || + strings.HasPrefix(fn.Synthetic, "thunk ") || + strings.HasSuffix(fn.name, "Error") { + // ok + } else { + s.errorf("nil Pkg") + } + } + if src, syn := fn.Synthetic == "", fn.Syntax() != nil; src != syn { + s.errorf("got fromSource=%t, hasSyntax=%t; want same values", src, syn) + } + for i, l := range fn.Locals { + if l.Parent() != fn { + s.errorf("Local %s at index %d has wrong parent", l.Name(), i) + } + if l.Heap { + s.errorf("Local %s at index %d has Heap flag set", l.Name(), i) + } + } + // Build the set of valid referrers. + s.instrs = make(map[Instruction]struct{}) + for _, b := range fn.Blocks { + for _, instr := range b.Instrs { + s.instrs[instr] = struct{}{} + } + } + for i, p := range fn.Params { + if p.Parent() != fn { + s.errorf("Param %s at index %d has wrong parent", p.Name(), i) + } + s.checkReferrerList(p) + } + for i, fv := range fn.FreeVars { + if fv.Parent() != fn { + s.errorf("FreeVar %s at index %d has wrong parent", fv.Name(), i) + } + s.checkReferrerList(fv) + } + + if fn.Blocks != nil && len(fn.Blocks) == 0 { + // Function _had_ blocks (so it's not external) but + // they were "optimized" away, even the entry block. + s.errorf("Blocks slice is non-nil but empty") + } + for i, b := range fn.Blocks { + if b == nil { + s.warnf("nil *BasicBlock at f.Blocks[%d]", i) + continue + } + s.checkBlock(b, i) + } + if fn.Recover != nil && fn.Blocks[fn.Recover.Index] != fn.Recover { + s.errorf("Recover block is not in Blocks slice") + } + + s.block = nil + for i, anon := range fn.AnonFuncs { + if anon.Parent() != fn { + s.errorf("AnonFuncs[%d]=%s but %s.Parent()=%s", i, anon, anon, anon.Parent()) + } + } + s.fn = nil + return !s.insane +} + +// sanityCheckPackage checks invariants of packages upon creation. +// It does not require that the package is built. +// Unlike sanityCheck (for functions), it just panics at the first error. +func sanityCheckPackage(pkg *Package) { + if pkg.Pkg == nil { + panic(fmt.Sprintf("Package %s has no Object", pkg)) + } + pkg.String() // must not crash + + for name, mem := range pkg.Members { + if name != mem.Name() { + panic(fmt.Sprintf("%s: %T.Name() = %s, want %s", + pkg.Pkg.Path(), mem, mem.Name(), name)) + } + obj := mem.Object() + if obj == nil { + // This check is sound because fields + // {Global,Function}.object have type + // types.Object. (If they were declared as + // *types.{Var,Func}, we'd have a non-empty + // interface containing a nil pointer.) + + continue // not all members have typechecker objects + } + if obj.Name() != name { + if obj.Name() == "init" && strings.HasPrefix(mem.Name(), "init#") { + // Ok. The name of a declared init function varies between + // its types.Func ("init") and its ssa.Function ("init#%d"). + } else { + panic(fmt.Sprintf("%s: %T.Object().Name() = %s, want %s", + pkg.Pkg.Path(), mem, obj.Name(), name)) + } + } + if obj.Pos() != mem.Pos() { + panic(fmt.Sprintf("%s Pos=%d obj.Pos=%d", mem, mem.Pos(), obj.Pos())) + } + } +} diff --git a/vendor/honnef.co/go/tools/ssa/source.go b/vendor/honnef.co/go/tools/ssa/source.go new file mode 100644 index 0000000..e17e023 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/source.go @@ -0,0 +1,299 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// This file defines utilities for working with source positions +// or source-level named entities ("objects"). + +// TODO(adonovan): test that {Value,Instruction}.Pos() positions match +// the originating syntax, as specified. + +import ( + "go/ast" + "go/token" + "go/types" + "log" +) + +// EnclosingFunction returns the function that contains the syntax +// node denoted by path. +// +// Syntax associated with package-level variable specifications is +// enclosed by the package's init() function. +// +// Returns nil if not found; reasons might include: +// - the node is not enclosed by any function. +// - the node is within an anonymous function (FuncLit) and +// its SSA function has not been created yet +// (pkg.Build() has not yet been called). +// +func EnclosingFunction(pkg *Package, path []ast.Node) *Function { + // Start with package-level function... + fn := findEnclosingPackageLevelFunction(pkg, path) + if fn == nil { + return nil // not in any function + } + + // ...then walk down the nested anonymous functions. + n := len(path) +outer: + for i := range path { + if lit, ok := path[n-1-i].(*ast.FuncLit); ok { + for _, anon := range fn.AnonFuncs { + if anon.Pos() == lit.Type.Func { + fn = anon + continue outer + } + } + // SSA function not found: + // - package not yet built, or maybe + // - builder skipped FuncLit in dead block + // (in principle; but currently the Builder + // generates even dead FuncLits). + return nil + } + } + return fn +} + +// HasEnclosingFunction returns true if the AST node denoted by path +// is contained within the declaration of some function or +// package-level variable. +// +// Unlike EnclosingFunction, the behaviour of this function does not +// depend on whether SSA code for pkg has been built, so it can be +// used to quickly reject check inputs that will cause +// EnclosingFunction to fail, prior to SSA building. +// +func HasEnclosingFunction(pkg *Package, path []ast.Node) bool { + return findEnclosingPackageLevelFunction(pkg, path) != nil +} + +// findEnclosingPackageLevelFunction returns the Function +// corresponding to the package-level function enclosing path. +// +func findEnclosingPackageLevelFunction(pkg *Package, path []ast.Node) *Function { + if n := len(path); n >= 2 { // [... {Gen,Func}Decl File] + switch decl := path[n-2].(type) { + case *ast.GenDecl: + if decl.Tok == token.VAR && n >= 3 { + // Package-level 'var' initializer. + return pkg.init + } + + case *ast.FuncDecl: + if decl.Recv == nil && decl.Name.Name == "init" { + // Explicit init() function. + for _, b := range pkg.init.Blocks { + for _, instr := range b.Instrs { + if instr, ok := instr.(*Call); ok { + if callee, ok := instr.Call.Value.(*Function); ok && callee.Pkg == pkg && callee.Pos() == decl.Name.NamePos { + return callee + } + } + } + } + // Hack: return non-nil when SSA is not yet + // built so that HasEnclosingFunction works. + return pkg.init + } + // Declared function/method. + return findNamedFunc(pkg, decl.Name.NamePos) + } + } + return nil // not in any function +} + +// findNamedFunc returns the named function whose FuncDecl.Ident is at +// position pos. +// +func findNamedFunc(pkg *Package, pos token.Pos) *Function { + // Look at all package members and method sets of named types. + // Not very efficient. + for _, mem := range pkg.Members { + switch mem := mem.(type) { + case *Function: + if mem.Pos() == pos { + return mem + } + case *Type: + mset := pkg.Prog.MethodSets.MethodSet(types.NewPointer(mem.Type())) + for i, n := 0, mset.Len(); i < n; i++ { + // Don't call Program.Method: avoid creating wrappers. + obj := mset.At(i).Obj().(*types.Func) + if obj.Pos() == pos { + if pkg.values[obj] == nil { + log.Println(obj) + } + return pkg.values[obj].(*Function) + } + } + } + } + return nil +} + +// ValueForExpr returns the SSA Value that corresponds to non-constant +// expression e. +// +// It returns nil if no value was found, e.g. +// - the expression is not lexically contained within f; +// - f was not built with debug information; or +// - e is a constant expression. (For efficiency, no debug +// information is stored for constants. Use +// go/types.Info.Types[e].Value instead.) +// - e is a reference to nil or a built-in function. +// - the value was optimised away. +// +// If e is an addressable expression used in an lvalue context, +// value is the address denoted by e, and isAddr is true. +// +// The types of e (or &e, if isAddr) and the result are equal +// (modulo "untyped" bools resulting from comparisons). +// +// (Tip: to find the ssa.Value given a source position, use +// importer.PathEnclosingInterval to locate the ast.Node, then +// EnclosingFunction to locate the Function, then ValueForExpr to find +// the ssa.Value.) +// +func (f *Function) ValueForExpr(e ast.Expr) (value Value, isAddr bool) { + if f.debugInfo() { // (opt) + e = unparen(e) + for _, b := range f.Blocks { + for _, instr := range b.Instrs { + if ref, ok := instr.(*DebugRef); ok { + if ref.Expr == e { + return ref.X, ref.IsAddr + } + } + } + } + } + return +} + +// --- Lookup functions for source-level named entities (types.Objects) --- + +// Package returns the SSA Package corresponding to the specified +// type-checker package object. +// It returns nil if no such SSA package has been created. +// +func (prog *Program) Package(obj *types.Package) *Package { + return prog.packages[obj] +} + +// packageLevelValue returns the package-level value corresponding to +// the specified named object, which may be a package-level const +// (*Const), var (*Global) or func (*Function) of some package in +// prog. It returns nil if the object is not found. +// +func (prog *Program) packageLevelValue(obj types.Object) Value { + if pkg, ok := prog.packages[obj.Pkg()]; ok { + return pkg.values[obj] + } + return nil +} + +// FuncValue returns the concrete Function denoted by the source-level +// named function obj, or nil if obj denotes an interface method. +// +// TODO(adonovan): check the invariant that obj.Type() matches the +// result's Signature, both in the params/results and in the receiver. +// +func (prog *Program) FuncValue(obj *types.Func) *Function { + fn, _ := prog.packageLevelValue(obj).(*Function) + return fn +} + +// ConstValue returns the SSA Value denoted by the source-level named +// constant obj. +// +func (prog *Program) ConstValue(obj *types.Const) *Const { + // TODO(adonovan): opt: share (don't reallocate) + // Consts for const objects and constant ast.Exprs. + + // Universal constant? {true,false,nil} + if obj.Parent() == types.Universe { + return NewConst(obj.Val(), obj.Type()) + } + // Package-level named constant? + if v := prog.packageLevelValue(obj); v != nil { + return v.(*Const) + } + return NewConst(obj.Val(), obj.Type()) +} + +// VarValue returns the SSA Value that corresponds to a specific +// identifier denoting the source-level named variable obj. +// +// VarValue returns nil if a local variable was not found, perhaps +// because its package was not built, the debug information was not +// requested during SSA construction, or the value was optimized away. +// +// ref is the path to an ast.Ident (e.g. from PathEnclosingInterval), +// and that ident must resolve to obj. +// +// pkg is the package enclosing the reference. (A reference to a var +// always occurs within a function, so we need to know where to find it.) +// +// If the identifier is a field selector and its base expression is +// non-addressable, then VarValue returns the value of that field. +// For example: +// func f() struct {x int} +// f().x // VarValue(x) returns a *Field instruction of type int +// +// All other identifiers denote addressable locations (variables). +// For them, VarValue may return either the variable's address or its +// value, even when the expression is evaluated only for its value; the +// situation is reported by isAddr, the second component of the result. +// +// If !isAddr, the returned value is the one associated with the +// specific identifier. For example, +// var x int // VarValue(x) returns Const 0 here +// x = 1 // VarValue(x) returns Const 1 here +// +// It is not specified whether the value or the address is returned in +// any particular case, as it may depend upon optimizations performed +// during SSA code generation, such as registerization, constant +// folding, avoidance of materialization of subexpressions, etc. +// +func (prog *Program) VarValue(obj *types.Var, pkg *Package, ref []ast.Node) (value Value, isAddr bool) { + // All references to a var are local to some function, possibly init. + fn := EnclosingFunction(pkg, ref) + if fn == nil { + return // e.g. def of struct field; SSA not built? + } + + id := ref[0].(*ast.Ident) + + // Defining ident of a parameter? + if id.Pos() == obj.Pos() { + for _, param := range fn.Params { + if param.Object() == obj { + return param, false + } + } + } + + // Other ident? + for _, b := range fn.Blocks { + for _, instr := range b.Instrs { + if dr, ok := instr.(*DebugRef); ok { + if dr.Pos() == id.Pos() { + return dr.X, dr.IsAddr + } + } + } + } + + // Defining ident of package-level var? + if v := prog.packageLevelValue(obj); v != nil { + return v.(*Global), true + } + + return // e.g. debug info not requested, or var optimized away +} diff --git a/vendor/honnef.co/go/tools/ssa/ssa.go b/vendor/honnef.co/go/tools/ssa/ssa.go new file mode 100644 index 0000000..ed280c7 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/ssa.go @@ -0,0 +1,1751 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// This package defines a high-level intermediate representation for +// Go programs using static single-assignment (SSA) form. + +import ( + "fmt" + "go/ast" + exact "go/constant" + "go/token" + "go/types" + "sync" + + "golang.org/x/tools/go/types/typeutil" +) + +// A Program is a partial or complete Go program converted to SSA form. +type Program struct { + Fset *token.FileSet // position information for the files of this Program + imported map[string]*Package // all importable Packages, keyed by import path + packages map[*types.Package]*Package // all loaded Packages, keyed by object + mode BuilderMode // set of mode bits for SSA construction + MethodSets typeutil.MethodSetCache // cache of type-checker's method-sets + + methodsMu sync.Mutex // guards the following maps: + methodSets typeutil.Map // maps type to its concrete methodSet + runtimeTypes typeutil.Map // types for which rtypes are needed + canon typeutil.Map // type canonicalization map + bounds map[*types.Func]*Function // bounds for curried x.Method closures + thunks map[selectionKey]*Function // thunks for T.Method expressions +} + +// A Package is a single analyzed Go package containing Members for +// all package-level functions, variables, constants and types it +// declares. These may be accessed directly via Members, or via the +// type-specific accessor methods Func, Type, Var and Const. +// +// Members also contains entries for "init" (the synthetic package +// initializer) and "init#%d", the nth declared init function, +// and unspecified other things too. +// +type Package struct { + Prog *Program // the owning program + Pkg *types.Package // the corresponding go/types.Package + Members map[string]Member // all package members keyed by name (incl. init and init#%d) + values map[types.Object]Value // package members (incl. types and methods), keyed by object + init *Function // Func("init"); the package's init function + debug bool // include full debug info in this package + + // The following fields are set transiently, then cleared + // after building. + buildOnce sync.Once // ensures package building occurs once + ninit int32 // number of init functions + info *types.Info // package type information + files []*ast.File // package ASTs +} + +// A Member is a member of a Go package, implemented by *NamedConst, +// *Global, *Function, or *Type; they are created by package-level +// const, var, func and type declarations respectively. +// +type Member interface { + Name() string // declared name of the package member + String() string // package-qualified name of the package member + RelString(*types.Package) string // like String, but relative refs are unqualified + Object() types.Object // typechecker's object for this member, if any + Pos() token.Pos // position of member's declaration, if known + Type() types.Type // type of the package member + Token() token.Token // token.{VAR,FUNC,CONST,TYPE} + Package() *Package // the containing package +} + +// A Type is a Member of a Package representing a package-level named type. +// +// Type() returns a *types.Named. +// +type Type struct { + object *types.TypeName + pkg *Package +} + +// A NamedConst is a Member of a Package representing a package-level +// named constant. +// +// Pos() returns the position of the declaring ast.ValueSpec.Names[*] +// identifier. +// +// NB: a NamedConst is not a Value; it contains a constant Value, which +// it augments with the name and position of its 'const' declaration. +// +type NamedConst struct { + object *types.Const + Value *Const + pos token.Pos + pkg *Package +} + +// A Value is an SSA value that can be referenced by an instruction. +type Value interface { + // Name returns the name of this value, and determines how + // this Value appears when used as an operand of an + // Instruction. + // + // This is the same as the source name for Parameters, + // Builtins, Functions, FreeVars, Globals. + // For constants, it is a representation of the constant's value + // and type. For all other Values this is the name of the + // virtual register defined by the instruction. + // + // The name of an SSA Value is not semantically significant, + // and may not even be unique within a function. + Name() string + + // If this value is an Instruction, String returns its + // disassembled form; otherwise it returns unspecified + // human-readable information about the Value, such as its + // kind, name and type. + String() string + + // Type returns the type of this value. Many instructions + // (e.g. IndexAddr) change their behaviour depending on the + // types of their operands. + Type() types.Type + + // Parent returns the function to which this Value belongs. + // It returns nil for named Functions, Builtin, Const and Global. + Parent() *Function + + // Referrers returns the list of instructions that have this + // value as one of their operands; it may contain duplicates + // if an instruction has a repeated operand. + // + // Referrers actually returns a pointer through which the + // caller may perform mutations to the object's state. + // + // Referrers is currently only defined if Parent()!=nil, + // i.e. for the function-local values FreeVar, Parameter, + // Functions (iff anonymous) and all value-defining instructions. + // It returns nil for named Functions, Builtin, Const and Global. + // + // Instruction.Operands contains the inverse of this relation. + Referrers() *[]Instruction + + // Pos returns the location of the AST token most closely + // associated with the operation that gave rise to this value, + // or token.NoPos if it was not explicit in the source. + // + // For each ast.Node type, a particular token is designated as + // the closest location for the expression, e.g. the Lparen + // for an *ast.CallExpr. This permits a compact but + // approximate mapping from Values to source positions for use + // in diagnostic messages, for example. + // + // (Do not use this position to determine which Value + // corresponds to an ast.Expr; use Function.ValueForExpr + // instead. NB: it requires that the function was built with + // debug information.) + Pos() token.Pos +} + +// An Instruction is an SSA instruction that computes a new Value or +// has some effect. +// +// An Instruction that defines a value (e.g. BinOp) also implements +// the Value interface; an Instruction that only has an effect (e.g. Store) +// does not. +// +type Instruction interface { + // String returns the disassembled form of this value. + // + // Examples of Instructions that are Values: + // "x + y" (BinOp) + // "len([])" (Call) + // Note that the name of the Value is not printed. + // + // Examples of Instructions that are not Values: + // "return x" (Return) + // "*y = x" (Store) + // + // (The separation Value.Name() from Value.String() is useful + // for some analyses which distinguish the operation from the + // value it defines, e.g., 'y = local int' is both an allocation + // of memory 'local int' and a definition of a pointer y.) + String() string + + // Parent returns the function to which this instruction + // belongs. + Parent() *Function + + // Block returns the basic block to which this instruction + // belongs. + Block() *BasicBlock + + // setBlock sets the basic block to which this instruction belongs. + setBlock(*BasicBlock) + + // Operands returns the operands of this instruction: the + // set of Values it references. + // + // Specifically, it appends their addresses to rands, a + // user-provided slice, and returns the resulting slice, + // permitting avoidance of memory allocation. + // + // The operands are appended in undefined order, but the order + // is consistent for a given Instruction; the addresses are + // always non-nil but may point to a nil Value. Clients may + // store through the pointers, e.g. to effect a value + // renaming. + // + // Value.Referrers is a subset of the inverse of this + // relation. (Referrers are not tracked for all types of + // Values.) + Operands(rands []*Value) []*Value + + // Pos returns the location of the AST token most closely + // associated with the operation that gave rise to this + // instruction, or token.NoPos if it was not explicit in the + // source. + // + // For each ast.Node type, a particular token is designated as + // the closest location for the expression, e.g. the Go token + // for an *ast.GoStmt. This permits a compact but approximate + // mapping from Instructions to source positions for use in + // diagnostic messages, for example. + // + // (Do not use this position to determine which Instruction + // corresponds to an ast.Expr; see the notes for Value.Pos. + // This position may be used to determine which non-Value + // Instruction corresponds to some ast.Stmts, but not all: If + // and Jump instructions have no Pos(), for example.) + Pos() token.Pos +} + +// A Node is a node in the SSA value graph. Every concrete type that +// implements Node is also either a Value, an Instruction, or both. +// +// Node contains the methods common to Value and Instruction, plus the +// Operands and Referrers methods generalized to return nil for +// non-Instructions and non-Values, respectively. +// +// Node is provided to simplify SSA graph algorithms. Clients should +// use the more specific and informative Value or Instruction +// interfaces where appropriate. +// +type Node interface { + // Common methods: + String() string + Pos() token.Pos + Parent() *Function + + // Partial methods: + Operands(rands []*Value) []*Value // nil for non-Instructions + Referrers() *[]Instruction // nil for non-Values +} + +// Function represents the parameters, results, and code of a function +// or method. +// +// If Blocks is nil, this indicates an external function for which no +// Go source code is available. In this case, FreeVars and Locals +// are nil too. Clients performing whole-program analysis must +// handle external functions specially. +// +// Blocks contains the function's control-flow graph (CFG). +// Blocks[0] is the function entry point; block order is not otherwise +// semantically significant, though it may affect the readability of +// the disassembly. +// To iterate over the blocks in dominance order, use DomPreorder(). +// +// Recover is an optional second entry point to which control resumes +// after a recovered panic. The Recover block may contain only a return +// statement, preceded by a load of the function's named return +// parameters, if any. +// +// A nested function (Parent()!=nil) that refers to one or more +// lexically enclosing local variables ("free variables") has FreeVars. +// Such functions cannot be called directly but require a +// value created by MakeClosure which, via its Bindings, supplies +// values for these parameters. +// +// If the function is a method (Signature.Recv() != nil) then the first +// element of Params is the receiver parameter. +// +// A Go package may declare many functions called "init". +// For each one, Object().Name() returns "init" but Name() returns +// "init#1", etc, in declaration order. +// +// Pos() returns the declaring ast.FuncLit.Type.Func or the position +// of the ast.FuncDecl.Name, if the function was explicit in the +// source. Synthetic wrappers, for which Synthetic != "", may share +// the same position as the function they wrap. +// Syntax.Pos() always returns the position of the declaring "func" token. +// +// Type() returns the function's Signature. +// +type Function struct { + name string + object types.Object // a declared *types.Func or one of its wrappers + method *types.Selection // info about provenance of synthetic methods + Signature *types.Signature + pos token.Pos + + Synthetic string // provenance of synthetic function; "" for true source functions + syntax ast.Node // *ast.Func{Decl,Lit}; replaced with simple ast.Node after build, unless debug mode + parent *Function // enclosing function if anon; nil if global + Pkg *Package // enclosing package; nil for shared funcs (wrappers and error.Error) + Prog *Program // enclosing program + Params []*Parameter // function parameters; for methods, includes receiver + FreeVars []*FreeVar // free variables whose values must be supplied by closure + Locals []*Alloc // local variables of this function + Blocks []*BasicBlock // basic blocks of the function; nil => external + Recover *BasicBlock // optional; control transfers here after recovered panic + AnonFuncs []*Function // anonymous functions directly beneath this one + referrers []Instruction // referring instructions (iff Parent() != nil) + + // The following fields are set transiently during building, + // then cleared. + currentBlock *BasicBlock // where to emit code + objects map[types.Object]Value // addresses of local variables + namedResults []*Alloc // tuple of named results + targets *targets // linked stack of branch targets + lblocks map[*ast.Object]*lblock // labelled blocks +} + +// BasicBlock represents an SSA basic block. +// +// The final element of Instrs is always an explicit transfer of +// control (If, Jump, Return, or Panic). +// +// A block may contain no Instructions only if it is unreachable, +// i.e., Preds is nil. Empty blocks are typically pruned. +// +// BasicBlocks and their Preds/Succs relation form a (possibly cyclic) +// graph independent of the SSA Value graph: the control-flow graph or +// CFG. It is illegal for multiple edges to exist between the same +// pair of blocks. +// +// Each BasicBlock is also a node in the dominator tree of the CFG. +// The tree may be navigated using Idom()/Dominees() and queried using +// Dominates(). +// +// The order of Preds and Succs is significant (to Phi and If +// instructions, respectively). +// +type BasicBlock struct { + Index int // index of this block within Parent().Blocks + Comment string // optional label; no semantic significance + parent *Function // parent function + Instrs []Instruction // instructions in order + Preds, Succs []*BasicBlock // predecessors and successors + succs2 [2]*BasicBlock // initial space for Succs + dom domInfo // dominator tree info + gaps int // number of nil Instrs (transient) + rundefers int // number of rundefers (transient) +} + +// Pure values ---------------------------------------- + +// A FreeVar represents a free variable of the function to which it +// belongs. +// +// FreeVars are used to implement anonymous functions, whose free +// variables are lexically captured in a closure formed by +// MakeClosure. The value of such a free var is an Alloc or another +// FreeVar and is considered a potentially escaping heap address, with +// pointer type. +// +// FreeVars are also used to implement bound method closures. Such a +// free var represents the receiver value and may be of any type that +// has concrete methods. +// +// Pos() returns the position of the value that was captured, which +// belongs to an enclosing function. +// +type FreeVar struct { + name string + typ types.Type + pos token.Pos + parent *Function + referrers []Instruction + + // Transiently needed during building. + outer Value // the Value captured from the enclosing context. +} + +// A Parameter represents an input parameter of a function. +// +type Parameter struct { + name string + object types.Object // a *types.Var; nil for non-source locals + typ types.Type + pos token.Pos + parent *Function + referrers []Instruction +} + +// A Const represents the value of a constant expression. +// +// The underlying type of a constant may be any boolean, numeric, or +// string type. In addition, a Const may represent the nil value of +// any reference type---interface, map, channel, pointer, slice, or +// function---but not "untyped nil". +// +// All source-level constant expressions are represented by a Const +// of the same type and value. +// +// Value holds the exact value of the constant, independent of its +// Type(), using the same representation as package go/exact uses for +// constants, or nil for a typed nil value. +// +// Pos() returns token.NoPos. +// +// Example printed form: +// 42:int +// "hello":untyped string +// 3+4i:MyComplex +// +type Const struct { + typ types.Type + Value exact.Value +} + +// A Global is a named Value holding the address of a package-level +// variable. +// +// Pos() returns the position of the ast.ValueSpec.Names[*] +// identifier. +// +type Global struct { + name string + object types.Object // a *types.Var; may be nil for synthetics e.g. init$guard + typ types.Type + pos token.Pos + + Pkg *Package +} + +// A Builtin represents a specific use of a built-in function, e.g. len. +// +// Builtins are immutable values. Builtins do not have addresses. +// Builtins can only appear in CallCommon.Func. +// +// Name() indicates the function: one of the built-in functions from the +// Go spec (excluding "make" and "new") or one of these ssa-defined +// intrinsics: +// +// // wrapnilchk returns ptr if non-nil, panics otherwise. +// // (For use in indirection wrappers.) +// func ssa:wrapnilchk(ptr *T, recvType, methodName string) *T +// +// Object() returns a *types.Builtin for built-ins defined by the spec, +// nil for others. +// +// Type() returns a *types.Signature representing the effective +// signature of the built-in for this call. +// +type Builtin struct { + name string + sig *types.Signature +} + +// Value-defining instructions ---------------------------------------- + +// The Alloc instruction reserves space for a variable of the given type, +// zero-initializes it, and yields its address. +// +// Alloc values are always addresses, and have pointer types, so the +// type of the allocated variable is actually +// Type().Underlying().(*types.Pointer).Elem(). +// +// If Heap is false, Alloc allocates space in the function's +// activation record (frame); we refer to an Alloc(Heap=false) as a +// "local" alloc. Each local Alloc returns the same address each time +// it is executed within the same activation; the space is +// re-initialized to zero. +// +// If Heap is true, Alloc allocates space in the heap; we +// refer to an Alloc(Heap=true) as a "new" alloc. Each new Alloc +// returns a different address each time it is executed. +// +// When Alloc is applied to a channel, map or slice type, it returns +// the address of an uninitialized (nil) reference of that kind; store +// the result of MakeSlice, MakeMap or MakeChan in that location to +// instantiate these types. +// +// Pos() returns the ast.CompositeLit.Lbrace for a composite literal, +// or the ast.CallExpr.Rparen for a call to new() or for a call that +// allocates a varargs slice. +// +// Example printed form: +// t0 = local int +// t1 = new int +// +type Alloc struct { + register + Comment string + Heap bool + index int // dense numbering; for lifting +} + +var _ Instruction = (*Sigma)(nil) +var _ Value = (*Sigma)(nil) + +type Sigma struct { + register + X Value + Branch bool +} + +func (p *Sigma) Value() Value { + v := p.X + for { + sigma, ok := v.(*Sigma) + if !ok { + break + } + v = sigma + } + return v +} + +func (p *Sigma) String() string { + return fmt.Sprintf("σ [%s.%t]", relName(p.X, p), p.Branch) +} + +// The Phi instruction represents an SSA φ-node, which combines values +// that differ across incoming control-flow edges and yields a new +// value. Within a block, all φ-nodes must appear before all non-φ +// nodes. +// +// Pos() returns the position of the && or || for short-circuit +// control-flow joins, or that of the *Alloc for φ-nodes inserted +// during SSA renaming. +// +// Example printed form: +// t2 = phi [0: t0, 1: t1] +// +type Phi struct { + register + Comment string // a hint as to its purpose + Edges []Value // Edges[i] is value for Block().Preds[i] +} + +// The Call instruction represents a function or method call. +// +// The Call instruction yields the function result if there is exactly +// one. Otherwise it returns a tuple, the components of which are +// accessed via Extract. +// +// See CallCommon for generic function call documentation. +// +// Pos() returns the ast.CallExpr.Lparen, if explicit in the source. +// +// Example printed form: +// t2 = println(t0, t1) +// t4 = t3() +// t7 = invoke t5.Println(...t6) +// +type Call struct { + register + Call CallCommon +} + +// The BinOp instruction yields the result of binary operation X Op Y. +// +// Pos() returns the ast.BinaryExpr.OpPos, if explicit in the source. +// +// Example printed form: +// t1 = t0 + 1:int +// +type BinOp struct { + register + // One of: + // ADD SUB MUL QUO REM + - * / % + // AND OR XOR SHL SHR AND_NOT & | ^ << >> &~ + // EQL LSS GTR NEQ LEQ GEQ == != < <= < >= + Op token.Token + X, Y Value +} + +// The UnOp instruction yields the result of Op X. +// ARROW is channel receive. +// MUL is pointer indirection (load). +// XOR is bitwise complement. +// SUB is negation. +// NOT is logical negation. +// +// If CommaOk and Op=ARROW, the result is a 2-tuple of the value above +// and a boolean indicating the success of the receive. The +// components of the tuple are accessed using Extract. +// +// Pos() returns the ast.UnaryExpr.OpPos, if explicit in the source. +// For receive operations (ARROW) implicit in ranging over a channel, +// Pos() returns the ast.RangeStmt.For. +// For implicit memory loads (STAR), Pos() returns the position of the +// most closely associated source-level construct; the details are not +// specified. +// +// Example printed form: +// t0 = *x +// t2 = <-t1,ok +// +type UnOp struct { + register + Op token.Token // One of: NOT SUB ARROW MUL XOR ! - <- * ^ + X Value + CommaOk bool +} + +// The ChangeType instruction applies to X a value-preserving type +// change to Type(). +// +// Type changes are permitted: +// - between a named type and its underlying type. +// - between two named types of the same underlying type. +// - between (possibly named) pointers to identical base types. +// - from a bidirectional channel to a read- or write-channel, +// optionally adding/removing a name. +// +// This operation cannot fail dynamically. +// +// Pos() returns the ast.CallExpr.Lparen, if the instruction arose +// from an explicit conversion in the source. +// +// Example printed form: +// t1 = changetype *int <- IntPtr (t0) +// +type ChangeType struct { + register + X Value +} + +// The Convert instruction yields the conversion of value X to type +// Type(). One or both of those types is basic (but possibly named). +// +// A conversion may change the value and representation of its operand. +// Conversions are permitted: +// - between real numeric types. +// - between complex numeric types. +// - between string and []byte or []rune. +// - between pointers and unsafe.Pointer. +// - between unsafe.Pointer and uintptr. +// - from (Unicode) integer to (UTF-8) string. +// A conversion may imply a type name change also. +// +// This operation cannot fail dynamically. +// +// Conversions of untyped string/number/bool constants to a specific +// representation are eliminated during SSA construction. +// +// Pos() returns the ast.CallExpr.Lparen, if the instruction arose +// from an explicit conversion in the source. +// +// Example printed form: +// t1 = convert []byte <- string (t0) +// +type Convert struct { + register + X Value +} + +// ChangeInterface constructs a value of one interface type from a +// value of another interface type known to be assignable to it. +// This operation cannot fail. +// +// Pos() returns the ast.CallExpr.Lparen if the instruction arose from +// an explicit T(e) conversion; the ast.TypeAssertExpr.Lparen if the +// instruction arose from an explicit e.(T) operation; or token.NoPos +// otherwise. +// +// Example printed form: +// t1 = change interface interface{} <- I (t0) +// +type ChangeInterface struct { + register + X Value +} + +// MakeInterface constructs an instance of an interface type from a +// value of a concrete type. +// +// Use Program.MethodSets.MethodSet(X.Type()) to find the method-set +// of X, and Program.Method(m) to find the implementation of a method. +// +// To construct the zero value of an interface type T, use: +// NewConst(exact.MakeNil(), T, pos) +// +// Pos() returns the ast.CallExpr.Lparen, if the instruction arose +// from an explicit conversion in the source. +// +// Example printed form: +// t1 = make interface{} <- int (42:int) +// t2 = make Stringer <- t0 +// +type MakeInterface struct { + register + X Value +} + +// The MakeClosure instruction yields a closure value whose code is +// Fn and whose free variables' values are supplied by Bindings. +// +// Type() returns a (possibly named) *types.Signature. +// +// Pos() returns the ast.FuncLit.Type.Func for a function literal +// closure or the ast.SelectorExpr.Sel for a bound method closure. +// +// Example printed form: +// t0 = make closure anon@1.2 [x y z] +// t1 = make closure bound$(main.I).add [i] +// +type MakeClosure struct { + register + Fn Value // always a *Function + Bindings []Value // values for each free variable in Fn.FreeVars +} + +// The MakeMap instruction creates a new hash-table-based map object +// and yields a value of kind map. +// +// Type() returns a (possibly named) *types.Map. +// +// Pos() returns the ast.CallExpr.Lparen, if created by make(map), or +// the ast.CompositeLit.Lbrack if created by a literal. +// +// Example printed form: +// t1 = make map[string]int t0 +// t1 = make StringIntMap t0 +// +type MakeMap struct { + register + Reserve Value // initial space reservation; nil => default +} + +// The MakeChan instruction creates a new channel object and yields a +// value of kind chan. +// +// Type() returns a (possibly named) *types.Chan. +// +// Pos() returns the ast.CallExpr.Lparen for the make(chan) that +// created it. +// +// Example printed form: +// t0 = make chan int 0 +// t0 = make IntChan 0 +// +type MakeChan struct { + register + Size Value // int; size of buffer; zero => synchronous. +} + +// The MakeSlice instruction yields a slice of length Len backed by a +// newly allocated array of length Cap. +// +// Both Len and Cap must be non-nil Values of integer type. +// +// (Alloc(types.Array) followed by Slice will not suffice because +// Alloc can only create arrays of constant length.) +// +// Type() returns a (possibly named) *types.Slice. +// +// Pos() returns the ast.CallExpr.Lparen for the make([]T) that +// created it. +// +// Example printed form: +// t1 = make []string 1:int t0 +// t1 = make StringSlice 1:int t0 +// +type MakeSlice struct { + register + Len Value + Cap Value +} + +// The Slice instruction yields a slice of an existing string, slice +// or *array X between optional integer bounds Low and High. +// +// Dynamically, this instruction panics if X evaluates to a nil *array +// pointer. +// +// Type() returns string if the type of X was string, otherwise a +// *types.Slice with the same element type as X. +// +// Pos() returns the ast.SliceExpr.Lbrack if created by a x[:] slice +// operation, the ast.CompositeLit.Lbrace if created by a literal, or +// NoPos if not explicit in the source (e.g. a variadic argument slice). +// +// Example printed form: +// t1 = slice t0[1:] +// +type Slice struct { + register + X Value // slice, string, or *array + Low, High, Max Value // each may be nil +} + +// The FieldAddr instruction yields the address of Field of *struct X. +// +// The field is identified by its index within the field list of the +// struct type of X. +// +// Dynamically, this instruction panics if X evaluates to a nil +// pointer. +// +// Type() returns a (possibly named) *types.Pointer. +// +// Pos() returns the position of the ast.SelectorExpr.Sel for the +// field, if explicit in the source. +// +// Example printed form: +// t1 = &t0.name [#1] +// +type FieldAddr struct { + register + X Value // *struct + Field int // index into X.Type().Deref().(*types.Struct).Fields +} + +// The Field instruction yields the Field of struct X. +// +// The field is identified by its index within the field list of the +// struct type of X; by using numeric indices we avoid ambiguity of +// package-local identifiers and permit compact representations. +// +// Pos() returns the position of the ast.SelectorExpr.Sel for the +// field, if explicit in the source. +// +// Example printed form: +// t1 = t0.name [#1] +// +type Field struct { + register + X Value // struct + Field int // index into X.Type().(*types.Struct).Fields +} + +// The IndexAddr instruction yields the address of the element at +// index Index of collection X. Index is an integer expression. +// +// The elements of maps and strings are not addressable; use Lookup or +// MapUpdate instead. +// +// Dynamically, this instruction panics if X evaluates to a nil *array +// pointer. +// +// Type() returns a (possibly named) *types.Pointer. +// +// Pos() returns the ast.IndexExpr.Lbrack for the index operation, if +// explicit in the source. +// +// Example printed form: +// t2 = &t0[t1] +// +type IndexAddr struct { + register + X Value // slice or *array, + Index Value // numeric index +} + +// The Index instruction yields element Index of array X. +// +// Pos() returns the ast.IndexExpr.Lbrack for the index operation, if +// explicit in the source. +// +// Example printed form: +// t2 = t0[t1] +// +type Index struct { + register + X Value // array + Index Value // integer index +} + +// The Lookup instruction yields element Index of collection X, a map +// or string. Index is an integer expression if X is a string or the +// appropriate key type if X is a map. +// +// If CommaOk, the result is a 2-tuple of the value above and a +// boolean indicating the result of a map membership test for the key. +// The components of the tuple are accessed using Extract. +// +// Pos() returns the ast.IndexExpr.Lbrack, if explicit in the source. +// +// Example printed form: +// t2 = t0[t1] +// t5 = t3[t4],ok +// +type Lookup struct { + register + X Value // string or map + Index Value // numeric or key-typed index + CommaOk bool // return a value,ok pair +} + +// SelectState is a helper for Select. +// It represents one goal state and its corresponding communication. +// +type SelectState struct { + Dir types.ChanDir // direction of case (SendOnly or RecvOnly) + Chan Value // channel to use (for send or receive) + Send Value // value to send (for send) + Pos token.Pos // position of token.ARROW + DebugNode ast.Node // ast.SendStmt or ast.UnaryExpr(<-) [debug mode] +} + +// The Select instruction tests whether (or blocks until) one +// of the specified sent or received states is entered. +// +// Let n be the number of States for which Dir==RECV and T_i (0<=i<n) +// be the element type of each such state's Chan. +// Select returns an n+2-tuple +// (index int, recvOk bool, r_0 T_0, ... r_n-1 T_n-1) +// The tuple's components, described below, must be accessed via the +// Extract instruction. +// +// If Blocking, select waits until exactly one state holds, i.e. a +// channel becomes ready for the designated operation of sending or +// receiving; select chooses one among the ready states +// pseudorandomly, performs the send or receive operation, and sets +// 'index' to the index of the chosen channel. +// +// If !Blocking, select doesn't block if no states hold; instead it +// returns immediately with index equal to -1. +// +// If the chosen channel was used for a receive, the r_i component is +// set to the received value, where i is the index of that state among +// all n receive states; otherwise r_i has the zero value of type T_i. +// Note that the receive index i is not the same as the state +// index index. +// +// The second component of the triple, recvOk, is a boolean whose value +// is true iff the selected operation was a receive and the receive +// successfully yielded a value. +// +// Pos() returns the ast.SelectStmt.Select. +// +// Example printed form: +// t3 = select nonblocking [<-t0, t1<-t2] +// t4 = select blocking [] +// +type Select struct { + register + States []*SelectState + Blocking bool +} + +// The Range instruction yields an iterator over the domain and range +// of X, which must be a string or map. +// +// Elements are accessed via Next. +// +// Type() returns an opaque and degenerate "rangeIter" type. +// +// Pos() returns the ast.RangeStmt.For. +// +// Example printed form: +// t0 = range "hello":string +// +type Range struct { + register + X Value // string or map +} + +// The Next instruction reads and advances the (map or string) +// iterator Iter and returns a 3-tuple value (ok, k, v). If the +// iterator is not exhausted, ok is true and k and v are the next +// elements of the domain and range, respectively. Otherwise ok is +// false and k and v are undefined. +// +// Components of the tuple are accessed using Extract. +// +// The IsString field distinguishes iterators over strings from those +// over maps, as the Type() alone is insufficient: consider +// map[int]rune. +// +// Type() returns a *types.Tuple for the triple (ok, k, v). +// The types of k and/or v may be types.Invalid. +// +// Example printed form: +// t1 = next t0 +// +type Next struct { + register + Iter Value + IsString bool // true => string iterator; false => map iterator. +} + +// The TypeAssert instruction tests whether interface value X has type +// AssertedType. +// +// If !CommaOk, on success it returns v, the result of the conversion +// (defined below); on failure it panics. +// +// If CommaOk: on success it returns a pair (v, true) where v is the +// result of the conversion; on failure it returns (z, false) where z +// is AssertedType's zero value. The components of the pair must be +// accessed using the Extract instruction. +// +// If AssertedType is a concrete type, TypeAssert checks whether the +// dynamic type in interface X is equal to it, and if so, the result +// of the conversion is a copy of the value in the interface. +// +// If AssertedType is an interface, TypeAssert checks whether the +// dynamic type of the interface is assignable to it, and if so, the +// result of the conversion is a copy of the interface value X. +// If AssertedType is a superinterface of X.Type(), the operation will +// fail iff the operand is nil. (Contrast with ChangeInterface, which +// performs no nil-check.) +// +// Type() reflects the actual type of the result, possibly a +// 2-types.Tuple; AssertedType is the asserted type. +// +// Pos() returns the ast.CallExpr.Lparen if the instruction arose from +// an explicit T(e) conversion; the ast.TypeAssertExpr.Lparen if the +// instruction arose from an explicit e.(T) operation; or the +// ast.CaseClause.Case if the instruction arose from a case of a +// type-switch statement. +// +// Example printed form: +// t1 = typeassert t0.(int) +// t3 = typeassert,ok t2.(T) +// +type TypeAssert struct { + register + X Value + AssertedType types.Type + CommaOk bool +} + +// The Extract instruction yields component Index of Tuple. +// +// This is used to access the results of instructions with multiple +// return values, such as Call, TypeAssert, Next, UnOp(ARROW) and +// IndexExpr(Map). +// +// Example printed form: +// t1 = extract t0 #1 +// +type Extract struct { + register + Tuple Value + Index int +} + +// Instructions executed for effect. They do not yield a value. -------------------- + +// The Jump instruction transfers control to the sole successor of its +// owning block. +// +// A Jump must be the last instruction of its containing BasicBlock. +// +// Pos() returns NoPos. +// +// Example printed form: +// jump done +// +type Jump struct { + anInstruction +} + +// The If instruction transfers control to one of the two successors +// of its owning block, depending on the boolean Cond: the first if +// true, the second if false. +// +// An If instruction must be the last instruction of its containing +// BasicBlock. +// +// Pos() returns NoPos. +// +// Example printed form: +// if t0 goto done else body +// +type If struct { + anInstruction + Cond Value +} + +// The Return instruction returns values and control back to the calling +// function. +// +// len(Results) is always equal to the number of results in the +// function's signature. +// +// If len(Results) > 1, Return returns a tuple value with the specified +// components which the caller must access using Extract instructions. +// +// There is no instruction to return a ready-made tuple like those +// returned by a "value,ok"-mode TypeAssert, Lookup or UnOp(ARROW) or +// a tail-call to a function with multiple result parameters. +// +// Return must be the last instruction of its containing BasicBlock. +// Such a block has no successors. +// +// Pos() returns the ast.ReturnStmt.Return, if explicit in the source. +// +// Example printed form: +// return +// return nil:I, 2:int +// +type Return struct { + anInstruction + Results []Value + pos token.Pos +} + +// The RunDefers instruction pops and invokes the entire stack of +// procedure calls pushed by Defer instructions in this function. +// +// It is legal to encounter multiple 'rundefers' instructions in a +// single control-flow path through a function; this is useful in +// the combined init() function, for example. +// +// Pos() returns NoPos. +// +// Example printed form: +// rundefers +// +type RunDefers struct { + anInstruction +} + +// The Panic instruction initiates a panic with value X. +// +// A Panic instruction must be the last instruction of its containing +// BasicBlock, which must have no successors. +// +// NB: 'go panic(x)' and 'defer panic(x)' do not use this instruction; +// they are treated as calls to a built-in function. +// +// Pos() returns the ast.CallExpr.Lparen if this panic was explicit +// in the source. +// +// Example printed form: +// panic t0 +// +type Panic struct { + anInstruction + X Value // an interface{} + pos token.Pos +} + +// The Go instruction creates a new goroutine and calls the specified +// function within it. +// +// See CallCommon for generic function call documentation. +// +// Pos() returns the ast.GoStmt.Go. +// +// Example printed form: +// go println(t0, t1) +// go t3() +// go invoke t5.Println(...t6) +// +type Go struct { + anInstruction + Call CallCommon + pos token.Pos +} + +// The Defer instruction pushes the specified call onto a stack of +// functions to be called by a RunDefers instruction or by a panic. +// +// See CallCommon for generic function call documentation. +// +// Pos() returns the ast.DeferStmt.Defer. +// +// Example printed form: +// defer println(t0, t1) +// defer t3() +// defer invoke t5.Println(...t6) +// +type Defer struct { + anInstruction + Call CallCommon + pos token.Pos +} + +// The Send instruction sends X on channel Chan. +// +// Pos() returns the ast.SendStmt.Arrow, if explicit in the source. +// +// Example printed form: +// send t0 <- t1 +// +type Send struct { + anInstruction + Chan, X Value + pos token.Pos +} + +// The Store instruction stores Val at address Addr. +// Stores can be of arbitrary types. +// +// Pos() returns the position of the source-level construct most closely +// associated with the memory store operation. +// Since implicit memory stores are numerous and varied and depend upon +// implementation choices, the details are not specified. +// +// Example printed form: +// *x = y +// +type Store struct { + anInstruction + Addr Value + Val Value + pos token.Pos +} + +// The BlankStore instruction is emitted for assignments to the blank +// identifier. +// +// BlankStore is a pseudo-instruction: it has no dynamic effect. +// +// Pos() returns NoPos. +// +// Example printed form: +// _ = t0 +// +type BlankStore struct { + anInstruction + Val Value +} + +// The MapUpdate instruction updates the association of Map[Key] to +// Value. +// +// Pos() returns the ast.KeyValueExpr.Colon or ast.IndexExpr.Lbrack, +// if explicit in the source. +// +// Example printed form: +// t0[t1] = t2 +// +type MapUpdate struct { + anInstruction + Map Value + Key Value + Value Value + pos token.Pos +} + +// A DebugRef instruction maps a source-level expression Expr to the +// SSA value X that represents the value (!IsAddr) or address (IsAddr) +// of that expression. +// +// DebugRef is a pseudo-instruction: it has no dynamic effect. +// +// Pos() returns Expr.Pos(), the start position of the source-level +// expression. This is not the same as the "designated" token as +// documented at Value.Pos(). e.g. CallExpr.Pos() does not return the +// position of the ("designated") Lparen token. +// +// If Expr is an *ast.Ident denoting a var or func, Object() returns +// the object; though this information can be obtained from the type +// checker, including it here greatly facilitates debugging. +// For non-Ident expressions, Object() returns nil. +// +// DebugRefs are generated only for functions built with debugging +// enabled; see Package.SetDebugMode() and the GlobalDebug builder +// mode flag. +// +// DebugRefs are not emitted for ast.Idents referring to constants or +// predeclared identifiers, since they are trivial and numerous. +// Nor are they emitted for ast.ParenExprs. +// +// (By representing these as instructions, rather than out-of-band, +// consistency is maintained during transformation passes by the +// ordinary SSA renaming machinery.) +// +// Example printed form: +// ; *ast.CallExpr @ 102:9 is t5 +// ; var x float64 @ 109:72 is x +// ; address of *ast.CompositeLit @ 216:10 is t0 +// +type DebugRef struct { + anInstruction + Expr ast.Expr // the referring expression (never *ast.ParenExpr) + object types.Object // the identity of the source var/func + IsAddr bool // Expr is addressable and X is the address it denotes + X Value // the value or address of Expr +} + +// Embeddable mix-ins and helpers for common parts of other structs. ----------- + +// register is a mix-in embedded by all SSA values that are also +// instructions, i.e. virtual registers, and provides a uniform +// implementation of most of the Value interface: Value.Name() is a +// numbered register (e.g. "t0"); the other methods are field accessors. +// +// Temporary names are automatically assigned to each register on +// completion of building a function in SSA form. +// +// Clients must not assume that the 'id' value (and the Name() derived +// from it) is unique within a function. As always in this API, +// semantics are determined only by identity; names exist only to +// facilitate debugging. +// +type register struct { + anInstruction + num int // "name" of virtual register, e.g. "t0". Not guaranteed unique. + typ types.Type // type of virtual register + pos token.Pos // position of source expression, or NoPos + referrers []Instruction +} + +// anInstruction is a mix-in embedded by all Instructions. +// It provides the implementations of the Block and setBlock methods. +type anInstruction struct { + block *BasicBlock // the basic block of this instruction +} + +// CallCommon is contained by Go, Defer and Call to hold the +// common parts of a function or method call. +// +// Each CallCommon exists in one of two modes, function call and +// interface method invocation, or "call" and "invoke" for short. +// +// 1. "call" mode: when Method is nil (!IsInvoke), a CallCommon +// represents an ordinary function call of the value in Value, +// which may be a *Builtin, a *Function or any other value of kind +// 'func'. +// +// Value may be one of: +// (a) a *Function, indicating a statically dispatched call +// to a package-level function, an anonymous function, or +// a method of a named type. +// (b) a *MakeClosure, indicating an immediately applied +// function literal with free variables. +// (c) a *Builtin, indicating a statically dispatched call +// to a built-in function. +// (d) any other value, indicating a dynamically dispatched +// function call. +// StaticCallee returns the identity of the callee in cases +// (a) and (b), nil otherwise. +// +// Args contains the arguments to the call. If Value is a method, +// Args[0] contains the receiver parameter. +// +// Example printed form: +// t2 = println(t0, t1) +// go t3() +// defer t5(...t6) +// +// 2. "invoke" mode: when Method is non-nil (IsInvoke), a CallCommon +// represents a dynamically dispatched call to an interface method. +// In this mode, Value is the interface value and Method is the +// interface's abstract method. Note: an abstract method may be +// shared by multiple interfaces due to embedding; Value.Type() +// provides the specific interface used for this call. +// +// Value is implicitly supplied to the concrete method implementation +// as the receiver parameter; in other words, Args[0] holds not the +// receiver but the first true argument. +// +// Example printed form: +// t1 = invoke t0.String() +// go invoke t3.Run(t2) +// defer invoke t4.Handle(...t5) +// +// For all calls to variadic functions (Signature().Variadic()), +// the last element of Args is a slice. +// +type CallCommon struct { + Value Value // receiver (invoke mode) or func value (call mode) + Method *types.Func // abstract method (invoke mode) + Args []Value // actual parameters (in static method call, includes receiver) + pos token.Pos // position of CallExpr.Lparen, iff explicit in source +} + +// IsInvoke returns true if this call has "invoke" (not "call") mode. +func (c *CallCommon) IsInvoke() bool { + return c.Method != nil +} + +func (c *CallCommon) Pos() token.Pos { return c.pos } + +// Signature returns the signature of the called function. +// +// For an "invoke"-mode call, the signature of the interface method is +// returned. +// +// In either "call" or "invoke" mode, if the callee is a method, its +// receiver is represented by sig.Recv, not sig.Params().At(0). +// +func (c *CallCommon) Signature() *types.Signature { + if c.Method != nil { + return c.Method.Type().(*types.Signature) + } + return c.Value.Type().Underlying().(*types.Signature) +} + +// StaticCallee returns the callee if this is a trivially static +// "call"-mode call to a function. +func (c *CallCommon) StaticCallee() *Function { + switch fn := c.Value.(type) { + case *Function: + return fn + case *MakeClosure: + return fn.Fn.(*Function) + } + return nil +} + +// Description returns a description of the mode of this call suitable +// for a user interface, e.g., "static method call". +func (c *CallCommon) Description() string { + switch fn := c.Value.(type) { + case *Builtin: + return "built-in function call" + case *MakeClosure: + return "static function closure call" + case *Function: + if fn.Signature.Recv() != nil { + return "static method call" + } + return "static function call" + } + if c.IsInvoke() { + return "dynamic method call" // ("invoke" mode) + } + return "dynamic function call" +} + +// The CallInstruction interface, implemented by *Go, *Defer and *Call, +// exposes the common parts of function-calling instructions, +// yet provides a way back to the Value defined by *Call alone. +// +type CallInstruction interface { + Instruction + Common() *CallCommon // returns the common parts of the call + Value() *Call // returns the result value of the call (*Call) or nil (*Go, *Defer) +} + +func (s *Call) Common() *CallCommon { return &s.Call } +func (s *Defer) Common() *CallCommon { return &s.Call } +func (s *Go) Common() *CallCommon { return &s.Call } + +func (s *Call) Value() *Call { return s } +func (s *Defer) Value() *Call { return nil } +func (s *Go) Value() *Call { return nil } + +func (v *Builtin) Type() types.Type { return v.sig } +func (v *Builtin) Name() string { return v.name } +func (*Builtin) Referrers() *[]Instruction { return nil } +func (v *Builtin) Pos() token.Pos { return token.NoPos } +func (v *Builtin) Object() types.Object { return types.Universe.Lookup(v.name) } +func (v *Builtin) Parent() *Function { return nil } + +func (v *FreeVar) Type() types.Type { return v.typ } +func (v *FreeVar) Name() string { return v.name } +func (v *FreeVar) Referrers() *[]Instruction { return &v.referrers } +func (v *FreeVar) Pos() token.Pos { return v.pos } +func (v *FreeVar) Parent() *Function { return v.parent } + +func (v *Global) Type() types.Type { return v.typ } +func (v *Global) Name() string { return v.name } +func (v *Global) Parent() *Function { return nil } +func (v *Global) Pos() token.Pos { return v.pos } +func (v *Global) Referrers() *[]Instruction { return nil } +func (v *Global) Token() token.Token { return token.VAR } +func (v *Global) Object() types.Object { return v.object } +func (v *Global) String() string { return v.RelString(nil) } +func (v *Global) Package() *Package { return v.Pkg } +func (v *Global) RelString(from *types.Package) string { return relString(v, from) } + +func (v *Function) Name() string { return v.name } +func (v *Function) Type() types.Type { return v.Signature } +func (v *Function) Pos() token.Pos { return v.pos } +func (v *Function) Token() token.Token { return token.FUNC } +func (v *Function) Object() types.Object { return v.object } +func (v *Function) String() string { return v.RelString(nil) } +func (v *Function) Package() *Package { return v.Pkg } +func (v *Function) Parent() *Function { return v.parent } +func (v *Function) Referrers() *[]Instruction { + if v.parent != nil { + return &v.referrers + } + return nil +} + +func (v *Parameter) Type() types.Type { return v.typ } +func (v *Parameter) Name() string { return v.name } +func (v *Parameter) Object() types.Object { return v.object } +func (v *Parameter) Referrers() *[]Instruction { return &v.referrers } +func (v *Parameter) Pos() token.Pos { return v.pos } +func (v *Parameter) Parent() *Function { return v.parent } + +func (v *Alloc) Type() types.Type { return v.typ } +func (v *Alloc) Referrers() *[]Instruction { return &v.referrers } +func (v *Alloc) Pos() token.Pos { return v.pos } + +func (v *register) Type() types.Type { return v.typ } +func (v *register) setType(typ types.Type) { v.typ = typ } +func (v *register) Name() string { return fmt.Sprintf("t%d", v.num) } +func (v *register) setNum(num int) { v.num = num } +func (v *register) Referrers() *[]Instruction { return &v.referrers } +func (v *register) Pos() token.Pos { return v.pos } +func (v *register) setPos(pos token.Pos) { v.pos = pos } + +func (v *anInstruction) Parent() *Function { return v.block.parent } +func (v *anInstruction) Block() *BasicBlock { return v.block } +func (v *anInstruction) setBlock(block *BasicBlock) { v.block = block } +func (v *anInstruction) Referrers() *[]Instruction { return nil } + +func (t *Type) Name() string { return t.object.Name() } +func (t *Type) Pos() token.Pos { return t.object.Pos() } +func (t *Type) Type() types.Type { return t.object.Type() } +func (t *Type) Token() token.Token { return token.TYPE } +func (t *Type) Object() types.Object { return t.object } +func (t *Type) String() string { return t.RelString(nil) } +func (t *Type) Package() *Package { return t.pkg } +func (t *Type) RelString(from *types.Package) string { return relString(t, from) } + +func (c *NamedConst) Name() string { return c.object.Name() } +func (c *NamedConst) Pos() token.Pos { return c.object.Pos() } +func (c *NamedConst) String() string { return c.RelString(nil) } +func (c *NamedConst) Type() types.Type { return c.object.Type() } +func (c *NamedConst) Token() token.Token { return token.CONST } +func (c *NamedConst) Object() types.Object { return c.object } +func (c *NamedConst) Package() *Package { return c.pkg } +func (c *NamedConst) RelString(from *types.Package) string { return relString(c, from) } + +// Func returns the package-level function of the specified name, +// or nil if not found. +// +func (p *Package) Func(name string) (f *Function) { + f, _ = p.Members[name].(*Function) + return +} + +// Var returns the package-level variable of the specified name, +// or nil if not found. +// +func (p *Package) Var(name string) (g *Global) { + g, _ = p.Members[name].(*Global) + return +} + +// Const returns the package-level constant of the specified name, +// or nil if not found. +// +func (p *Package) Const(name string) (c *NamedConst) { + c, _ = p.Members[name].(*NamedConst) + return +} + +// Type returns the package-level type of the specified name, +// or nil if not found. +// +func (p *Package) Type(name string) (t *Type) { + t, _ = p.Members[name].(*Type) + return +} + +func (v *Call) Pos() token.Pos { return v.Call.pos } +func (s *Defer) Pos() token.Pos { return s.pos } +func (s *Go) Pos() token.Pos { return s.pos } +func (s *MapUpdate) Pos() token.Pos { return s.pos } +func (s *Panic) Pos() token.Pos { return s.pos } +func (s *Return) Pos() token.Pos { return s.pos } +func (s *Send) Pos() token.Pos { return s.pos } +func (s *Store) Pos() token.Pos { return s.pos } +func (s *BlankStore) Pos() token.Pos { return token.NoPos } +func (s *If) Pos() token.Pos { return token.NoPos } +func (s *Jump) Pos() token.Pos { return token.NoPos } +func (s *RunDefers) Pos() token.Pos { return token.NoPos } +func (s *DebugRef) Pos() token.Pos { return s.Expr.Pos() } + +// Operands. + +func (v *Alloc) Operands(rands []*Value) []*Value { + return rands +} + +func (v *BinOp) Operands(rands []*Value) []*Value { + return append(rands, &v.X, &v.Y) +} + +func (c *CallCommon) Operands(rands []*Value) []*Value { + rands = append(rands, &c.Value) + for i := range c.Args { + rands = append(rands, &c.Args[i]) + } + return rands +} + +func (s *Go) Operands(rands []*Value) []*Value { + return s.Call.Operands(rands) +} + +func (s *Call) Operands(rands []*Value) []*Value { + return s.Call.Operands(rands) +} + +func (s *Defer) Operands(rands []*Value) []*Value { + return s.Call.Operands(rands) +} + +func (v *ChangeInterface) Operands(rands []*Value) []*Value { + return append(rands, &v.X) +} + +func (v *ChangeType) Operands(rands []*Value) []*Value { + return append(rands, &v.X) +} + +func (v *Convert) Operands(rands []*Value) []*Value { + return append(rands, &v.X) +} + +func (s *DebugRef) Operands(rands []*Value) []*Value { + return append(rands, &s.X) +} + +func (v *Extract) Operands(rands []*Value) []*Value { + return append(rands, &v.Tuple) +} + +func (v *Field) Operands(rands []*Value) []*Value { + return append(rands, &v.X) +} + +func (v *FieldAddr) Operands(rands []*Value) []*Value { + return append(rands, &v.X) +} + +func (s *If) Operands(rands []*Value) []*Value { + return append(rands, &s.Cond) +} + +func (v *Index) Operands(rands []*Value) []*Value { + return append(rands, &v.X, &v.Index) +} + +func (v *IndexAddr) Operands(rands []*Value) []*Value { + return append(rands, &v.X, &v.Index) +} + +func (*Jump) Operands(rands []*Value) []*Value { + return rands +} + +func (v *Lookup) Operands(rands []*Value) []*Value { + return append(rands, &v.X, &v.Index) +} + +func (v *MakeChan) Operands(rands []*Value) []*Value { + return append(rands, &v.Size) +} + +func (v *MakeClosure) Operands(rands []*Value) []*Value { + rands = append(rands, &v.Fn) + for i := range v.Bindings { + rands = append(rands, &v.Bindings[i]) + } + return rands +} + +func (v *MakeInterface) Operands(rands []*Value) []*Value { + return append(rands, &v.X) +} + +func (v *MakeMap) Operands(rands []*Value) []*Value { + return append(rands, &v.Reserve) +} + +func (v *MakeSlice) Operands(rands []*Value) []*Value { + return append(rands, &v.Len, &v.Cap) +} + +func (v *MapUpdate) Operands(rands []*Value) []*Value { + return append(rands, &v.Map, &v.Key, &v.Value) +} + +func (v *Next) Operands(rands []*Value) []*Value { + return append(rands, &v.Iter) +} + +func (s *Panic) Operands(rands []*Value) []*Value { + return append(rands, &s.X) +} + +func (v *Sigma) Operands(rands []*Value) []*Value { + return append(rands, &v.X) +} + +func (v *Phi) Operands(rands []*Value) []*Value { + for i := range v.Edges { + rands = append(rands, &v.Edges[i]) + } + return rands +} + +func (v *Range) Operands(rands []*Value) []*Value { + return append(rands, &v.X) +} + +func (s *Return) Operands(rands []*Value) []*Value { + for i := range s.Results { + rands = append(rands, &s.Results[i]) + } + return rands +} + +func (*RunDefers) Operands(rands []*Value) []*Value { + return rands +} + +func (v *Select) Operands(rands []*Value) []*Value { + for i := range v.States { + rands = append(rands, &v.States[i].Chan, &v.States[i].Send) + } + return rands +} + +func (s *Send) Operands(rands []*Value) []*Value { + return append(rands, &s.Chan, &s.X) +} + +func (v *Slice) Operands(rands []*Value) []*Value { + return append(rands, &v.X, &v.Low, &v.High, &v.Max) +} + +func (s *Store) Operands(rands []*Value) []*Value { + return append(rands, &s.Addr, &s.Val) +} + +func (s *BlankStore) Operands(rands []*Value) []*Value { + return append(rands, &s.Val) +} + +func (v *TypeAssert) Operands(rands []*Value) []*Value { + return append(rands, &v.X) +} + +func (v *UnOp) Operands(rands []*Value) []*Value { + return append(rands, &v.X) +} + +// Non-Instruction Values: +func (v *Builtin) Operands(rands []*Value) []*Value { return rands } +func (v *FreeVar) Operands(rands []*Value) []*Value { return rands } +func (v *Const) Operands(rands []*Value) []*Value { return rands } +func (v *Function) Operands(rands []*Value) []*Value { return rands } +func (v *Global) Operands(rands []*Value) []*Value { return rands } +func (v *Parameter) Operands(rands []*Value) []*Value { return rands } diff --git a/vendor/honnef.co/go/tools/ssa/ssautil/load.go b/vendor/honnef.co/go/tools/ssa/ssautil/load.go new file mode 100644 index 0000000..2fc108f --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/ssautil/load.go @@ -0,0 +1,97 @@ +// Copyright 2015 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssautil + +// This file defines utility functions for constructing programs in SSA form. + +import ( + "go/ast" + "go/token" + "go/types" + + "golang.org/x/tools/go/loader" + "honnef.co/go/tools/ssa" +) + +// CreateProgram returns a new program in SSA form, given a program +// loaded from source. An SSA package is created for each transitively +// error-free package of lprog. +// +// Code for bodies of functions is not built until Build is called +// on the result. +// +// mode controls diagnostics and checking during SSA construction. +// +func CreateProgram(lprog *loader.Program, mode ssa.BuilderMode) *ssa.Program { + prog := ssa.NewProgram(lprog.Fset, mode) + + for _, info := range lprog.AllPackages { + if info.TransitivelyErrorFree { + prog.CreatePackage(info.Pkg, info.Files, &info.Info, info.Importable) + } + } + + return prog +} + +// BuildPackage builds an SSA program with IR for a single package. +// +// It populates pkg by type-checking the specified file ASTs. All +// dependencies are loaded using the importer specified by tc, which +// typically loads compiler export data; SSA code cannot be built for +// those packages. BuildPackage then constructs an ssa.Program with all +// dependency packages created, and builds and returns the SSA package +// corresponding to pkg. +// +// The caller must have set pkg.Path() to the import path. +// +// The operation fails if there were any type-checking or import errors. +// +// See ../ssa/example_test.go for an example. +// +func BuildPackage(tc *types.Config, fset *token.FileSet, pkg *types.Package, files []*ast.File, mode ssa.BuilderMode) (*ssa.Package, *types.Info, error) { + if fset == nil { + panic("no token.FileSet") + } + if pkg.Path() == "" { + panic("package has no import path") + } + + info := &types.Info{ + Types: make(map[ast.Expr]types.TypeAndValue), + Defs: make(map[*ast.Ident]types.Object), + Uses: make(map[*ast.Ident]types.Object), + Implicits: make(map[ast.Node]types.Object), + Scopes: make(map[ast.Node]*types.Scope), + Selections: make(map[*ast.SelectorExpr]*types.Selection), + } + if err := types.NewChecker(tc, fset, pkg, info).Files(files); err != nil { + return nil, nil, err + } + + prog := ssa.NewProgram(fset, mode) + + // Create SSA packages for all imports. + // Order is not significant. + created := make(map[*types.Package]bool) + var createAll func(pkgs []*types.Package) + createAll = func(pkgs []*types.Package) { + for _, p := range pkgs { + if !created[p] { + created[p] = true + prog.CreatePackage(p, nil, nil, true) + createAll(p.Imports()) + } + } + } + createAll(pkg.Imports()) + + // Create and build the primary package. + ssapkg := prog.CreatePackage(pkg, files, info, false) + ssapkg.Build() + return ssapkg, info, nil +} diff --git a/vendor/honnef.co/go/tools/ssa/ssautil/switch.go b/vendor/honnef.co/go/tools/ssa/ssautil/switch.go new file mode 100644 index 0000000..ef698b3 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/ssautil/switch.go @@ -0,0 +1,236 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssautil + +// This file implements discovery of switch and type-switch constructs +// from low-level control flow. +// +// Many techniques exist for compiling a high-level switch with +// constant cases to efficient machine code. The optimal choice will +// depend on the data type, the specific case values, the code in the +// body of each case, and the hardware. +// Some examples: +// - a lookup table (for a switch that maps constants to constants) +// - a computed goto +// - a binary tree +// - a perfect hash +// - a two-level switch (to partition constant strings by their first byte). + +import ( + "bytes" + "fmt" + "go/token" + "go/types" + + "honnef.co/go/tools/ssa" +) + +// A ConstCase represents a single constant comparison. +// It is part of a Switch. +type ConstCase struct { + Block *ssa.BasicBlock // block performing the comparison + Body *ssa.BasicBlock // body of the case + Value *ssa.Const // case comparand +} + +// A TypeCase represents a single type assertion. +// It is part of a Switch. +type TypeCase struct { + Block *ssa.BasicBlock // block performing the type assert + Body *ssa.BasicBlock // body of the case + Type types.Type // case type + Binding ssa.Value // value bound by this case +} + +// A Switch is a logical high-level control flow operation +// (a multiway branch) discovered by analysis of a CFG containing +// only if/else chains. It is not part of the ssa.Instruction set. +// +// One of ConstCases and TypeCases has length >= 2; +// the other is nil. +// +// In a value switch, the list of cases may contain duplicate constants. +// A type switch may contain duplicate types, or types assignable +// to an interface type also in the list. +// TODO(adonovan): eliminate such duplicates. +// +type Switch struct { + Start *ssa.BasicBlock // block containing start of if/else chain + X ssa.Value // the switch operand + ConstCases []ConstCase // ordered list of constant comparisons + TypeCases []TypeCase // ordered list of type assertions + Default *ssa.BasicBlock // successor if all comparisons fail +} + +func (sw *Switch) String() string { + // We represent each block by the String() of its + // first Instruction, e.g. "print(42:int)". + var buf bytes.Buffer + if sw.ConstCases != nil { + fmt.Fprintf(&buf, "switch %s {\n", sw.X.Name()) + for _, c := range sw.ConstCases { + fmt.Fprintf(&buf, "case %s: %s\n", c.Value, c.Body.Instrs[0]) + } + } else { + fmt.Fprintf(&buf, "switch %s.(type) {\n", sw.X.Name()) + for _, c := range sw.TypeCases { + fmt.Fprintf(&buf, "case %s %s: %s\n", + c.Binding.Name(), c.Type, c.Body.Instrs[0]) + } + } + if sw.Default != nil { + fmt.Fprintf(&buf, "default: %s\n", sw.Default.Instrs[0]) + } + fmt.Fprintf(&buf, "}") + return buf.String() +} + +// Switches examines the control-flow graph of fn and returns the +// set of inferred value and type switches. A value switch tests an +// ssa.Value for equality against two or more compile-time constant +// values. Switches involving link-time constants (addresses) are +// ignored. A type switch type-asserts an ssa.Value against two or +// more types. +// +// The switches are returned in dominance order. +// +// The resulting switches do not necessarily correspond to uses of the +// 'switch' keyword in the source: for example, a single source-level +// switch statement with non-constant cases may result in zero, one or +// many Switches, one per plural sequence of constant cases. +// Switches may even be inferred from if/else- or goto-based control flow. +// (In general, the control flow constructs of the source program +// cannot be faithfully reproduced from the SSA representation.) +// +func Switches(fn *ssa.Function) []Switch { + // Traverse the CFG in dominance order, so we don't + // enter an if/else-chain in the middle. + var switches []Switch + seen := make(map[*ssa.BasicBlock]bool) // TODO(adonovan): opt: use ssa.blockSet + for _, b := range fn.DomPreorder() { + if x, k := isComparisonBlock(b); x != nil { + // Block b starts a switch. + sw := Switch{Start: b, X: x} + valueSwitch(&sw, k, seen) + if len(sw.ConstCases) > 1 { + switches = append(switches, sw) + } + } + + if y, x, T := isTypeAssertBlock(b); y != nil { + // Block b starts a type switch. + sw := Switch{Start: b, X: x} + typeSwitch(&sw, y, T, seen) + if len(sw.TypeCases) > 1 { + switches = append(switches, sw) + } + } + } + return switches +} + +func valueSwitch(sw *Switch, k *ssa.Const, seen map[*ssa.BasicBlock]bool) { + b := sw.Start + x := sw.X + for x == sw.X { + if seen[b] { + break + } + seen[b] = true + + sw.ConstCases = append(sw.ConstCases, ConstCase{ + Block: b, + Body: b.Succs[0], + Value: k, + }) + b = b.Succs[1] + if len(b.Instrs) > 2 { + // Block b contains not just 'if x == k', + // so it may have side effects that + // make it unsafe to elide. + break + } + if len(b.Preds) != 1 { + // Block b has multiple predecessors, + // so it cannot be treated as a case. + break + } + x, k = isComparisonBlock(b) + } + sw.Default = b +} + +func typeSwitch(sw *Switch, y ssa.Value, T types.Type, seen map[*ssa.BasicBlock]bool) { + b := sw.Start + x := sw.X + for x == sw.X { + if seen[b] { + break + } + seen[b] = true + + sw.TypeCases = append(sw.TypeCases, TypeCase{ + Block: b, + Body: b.Succs[0], + Type: T, + Binding: y, + }) + b = b.Succs[1] + if len(b.Instrs) > 4 { + // Block b contains not just + // {TypeAssert; Extract #0; Extract #1; If} + // so it may have side effects that + // make it unsafe to elide. + break + } + if len(b.Preds) != 1 { + // Block b has multiple predecessors, + // so it cannot be treated as a case. + break + } + y, x, T = isTypeAssertBlock(b) + } + sw.Default = b +} + +// isComparisonBlock returns the operands (v, k) if a block ends with +// a comparison v==k, where k is a compile-time constant. +// +func isComparisonBlock(b *ssa.BasicBlock) (v ssa.Value, k *ssa.Const) { + if n := len(b.Instrs); n >= 2 { + if i, ok := b.Instrs[n-1].(*ssa.If); ok { + if binop, ok := i.Cond.(*ssa.BinOp); ok && binop.Block() == b && binop.Op == token.EQL { + if k, ok := binop.Y.(*ssa.Const); ok { + return binop.X, k + } + if k, ok := binop.X.(*ssa.Const); ok { + return binop.Y, k + } + } + } + } + return +} + +// isTypeAssertBlock returns the operands (y, x, T) if a block ends with +// a type assertion "if y, ok := x.(T); ok {". +// +func isTypeAssertBlock(b *ssa.BasicBlock) (y, x ssa.Value, T types.Type) { + if n := len(b.Instrs); n >= 4 { + if i, ok := b.Instrs[n-1].(*ssa.If); ok { + if ext1, ok := i.Cond.(*ssa.Extract); ok && ext1.Block() == b && ext1.Index == 1 { + if ta, ok := ext1.Tuple.(*ssa.TypeAssert); ok && ta.Block() == b { + // hack: relies upon instruction ordering. + if ext0, ok := b.Instrs[n-3].(*ssa.Extract); ok { + return ext0, ta.X, ta.AssertedType + } + } + } + } + } + return +} diff --git a/vendor/honnef.co/go/tools/ssa/ssautil/visit.go b/vendor/honnef.co/go/tools/ssa/ssautil/visit.go new file mode 100644 index 0000000..5c14845 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/ssautil/visit.go @@ -0,0 +1,79 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssautil // import "honnef.co/go/tools/ssa/ssautil" + +import "honnef.co/go/tools/ssa" + +// This file defines utilities for visiting the SSA representation of +// a Program. +// +// TODO(adonovan): test coverage. + +// AllFunctions finds and returns the set of functions potentially +// needed by program prog, as determined by a simple linker-style +// reachability algorithm starting from the members and method-sets of +// each package. The result may include anonymous functions and +// synthetic wrappers. +// +// Precondition: all packages are built. +// +func AllFunctions(prog *ssa.Program) map[*ssa.Function]bool { + visit := visitor{ + prog: prog, + seen: make(map[*ssa.Function]bool), + } + visit.program() + return visit.seen +} + +type visitor struct { + prog *ssa.Program + seen map[*ssa.Function]bool +} + +func (visit *visitor) program() { + for _, pkg := range visit.prog.AllPackages() { + for _, mem := range pkg.Members { + if fn, ok := mem.(*ssa.Function); ok { + visit.function(fn) + } + } + } + for _, T := range visit.prog.RuntimeTypes() { + mset := visit.prog.MethodSets.MethodSet(T) + for i, n := 0, mset.Len(); i < n; i++ { + visit.function(visit.prog.MethodValue(mset.At(i))) + } + } +} + +func (visit *visitor) function(fn *ssa.Function) { + if !visit.seen[fn] { + visit.seen[fn] = true + var buf [10]*ssa.Value // avoid alloc in common case + for _, b := range fn.Blocks { + for _, instr := range b.Instrs { + for _, op := range instr.Operands(buf[:0]) { + if fn, ok := (*op).(*ssa.Function); ok { + visit.function(fn) + } + } + } + } + } +} + +// MainPackages returns the subset of the specified packages +// named "main" that define a main function. +// The result may include synthetic "testmain" packages. +func MainPackages(pkgs []*ssa.Package) []*ssa.Package { + var mains []*ssa.Package + for _, pkg := range pkgs { + if pkg.Pkg.Name() == "main" && pkg.Func("main") != nil { + mains = append(mains, pkg) + } + } + return mains +} diff --git a/vendor/honnef.co/go/tools/ssa/testmain.go b/vendor/honnef.co/go/tools/ssa/testmain.go new file mode 100644 index 0000000..2b89724 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/testmain.go @@ -0,0 +1,266 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// CreateTestMainPackage synthesizes a main package that runs all the +// tests of the supplied packages. +// It is closely coupled to $GOROOT/src/cmd/go/test.go and $GOROOT/src/testing. +// +// TODO(adonovan): this file no longer needs to live in the ssa package. +// Move it to ssautil. + +import ( + "bytes" + "fmt" + "go/ast" + "go/parser" + "go/types" + "log" + "os" + "strings" + "text/template" +) + +// FindTests returns the Test, Benchmark, and Example functions +// (as defined by "go test") defined in the specified package, +// and its TestMain function, if any. +func FindTests(pkg *Package) (tests, benchmarks, examples []*Function, main *Function) { + prog := pkg.Prog + + // The first two of these may be nil: if the program doesn't import "testing", + // it can't contain any tests, but it may yet contain Examples. + var testSig *types.Signature // func(*testing.T) + var benchmarkSig *types.Signature // func(*testing.B) + var exampleSig = types.NewSignature(nil, nil, nil, false) // func() + + // Obtain the types from the parameters of testing.MainStart. + if testingPkg := prog.ImportedPackage("testing"); testingPkg != nil { + mainStart := testingPkg.Func("MainStart") + params := mainStart.Signature.Params() + testSig = funcField(params.At(1).Type()) + benchmarkSig = funcField(params.At(2).Type()) + + // Does the package define this function? + // func TestMain(*testing.M) + if f := pkg.Func("TestMain"); f != nil { + sig := f.Type().(*types.Signature) + starM := mainStart.Signature.Results().At(0).Type() // *testing.M + if sig.Results().Len() == 0 && + sig.Params().Len() == 1 && + types.Identical(sig.Params().At(0).Type(), starM) { + main = f + } + } + } + + // TODO(adonovan): use a stable order, e.g. lexical. + for _, mem := range pkg.Members { + if f, ok := mem.(*Function); ok && + ast.IsExported(f.Name()) && + strings.HasSuffix(prog.Fset.Position(f.Pos()).Filename, "_test.go") { + + switch { + case testSig != nil && isTestSig(f, "Test", testSig): + tests = append(tests, f) + case benchmarkSig != nil && isTestSig(f, "Benchmark", benchmarkSig): + benchmarks = append(benchmarks, f) + case isTestSig(f, "Example", exampleSig): + examples = append(examples, f) + default: + continue + } + } + } + return +} + +// Like isTest, but checks the signature too. +func isTestSig(f *Function, prefix string, sig *types.Signature) bool { + return isTest(f.Name(), prefix) && types.Identical(f.Signature, sig) +} + +// Given the type of one of the three slice parameters of testing.Main, +// returns the function type. +func funcField(slice types.Type) *types.Signature { + return slice.(*types.Slice).Elem().Underlying().(*types.Struct).Field(1).Type().(*types.Signature) +} + +// isTest tells whether name looks like a test (or benchmark, according to prefix). +// It is a Test (say) if there is a character after Test that is not a lower-case letter. +// We don't want TesticularCancer. +// Plundered from $GOROOT/src/cmd/go/test.go +func isTest(name, prefix string) bool { + if !strings.HasPrefix(name, prefix) { + return false + } + if len(name) == len(prefix) { // "Test" is ok + return true + } + return ast.IsExported(name[len(prefix):]) +} + +// CreateTestMainPackage creates and returns a synthetic "testmain" +// package for the specified package if it defines tests, benchmarks or +// executable examples, or nil otherwise. The new package is named +// "main" and provides a function named "main" that runs the tests, +// similar to the one that would be created by the 'go test' tool. +// +// Subsequent calls to prog.AllPackages include the new package. +// The package pkg must belong to the program prog. +func (prog *Program) CreateTestMainPackage(pkg *Package) *Package { + if pkg.Prog != prog { + log.Fatal("Package does not belong to Program") + } + + // Template data + var data struct { + Pkg *Package + Tests, Benchmarks, Examples []*Function + Main *Function + Go18 bool + } + data.Pkg = pkg + + // Enumerate tests. + data.Tests, data.Benchmarks, data.Examples, data.Main = FindTests(pkg) + if data.Main == nil && + data.Tests == nil && data.Benchmarks == nil && data.Examples == nil { + return nil + } + + // Synthesize source for testmain package. + path := pkg.Pkg.Path() + "$testmain" + tmpl := testmainTmpl + if testingPkg := prog.ImportedPackage("testing"); testingPkg != nil { + // In Go 1.8, testing.MainStart's first argument is an interface, not a func. + data.Go18 = types.IsInterface(testingPkg.Func("MainStart").Signature.Params().At(0).Type()) + } else { + // The program does not import "testing", but FindTests + // returned non-nil, which must mean there were Examples + // but no Test, Benchmark, or TestMain functions. + + // We'll simply call them from testmain.main; this will + // ensure they don't panic, but will not check any + // "Output:" comments. + // (We should not execute an Example that has no + // "Output:" comment, but it's impossible to tell here.) + tmpl = examplesOnlyTmpl + } + var buf bytes.Buffer + if err := tmpl.Execute(&buf, data); err != nil { + log.Fatalf("internal error expanding template for %s: %v", path, err) + } + if false { // debugging + fmt.Fprintln(os.Stderr, buf.String()) + } + + // Parse and type-check the testmain package. + f, err := parser.ParseFile(prog.Fset, path+".go", &buf, parser.Mode(0)) + if err != nil { + log.Fatalf("internal error parsing %s: %v", path, err) + } + conf := types.Config{ + DisableUnusedImportCheck: true, + Importer: importer{pkg}, + } + files := []*ast.File{f} + info := &types.Info{ + Types: make(map[ast.Expr]types.TypeAndValue), + Defs: make(map[*ast.Ident]types.Object), + Uses: make(map[*ast.Ident]types.Object), + Implicits: make(map[ast.Node]types.Object), + Scopes: make(map[ast.Node]*types.Scope), + Selections: make(map[*ast.SelectorExpr]*types.Selection), + } + testmainPkg, err := conf.Check(path, prog.Fset, files, info) + if err != nil { + log.Fatalf("internal error type-checking %s: %v", path, err) + } + + // Create and build SSA code. + testmain := prog.CreatePackage(testmainPkg, files, info, false) + testmain.SetDebugMode(false) + testmain.Build() + testmain.Func("main").Synthetic = "test main function" + testmain.Func("init").Synthetic = "package initializer" + return testmain +} + +// An implementation of types.Importer for an already loaded SSA program. +type importer struct { + pkg *Package // package under test; may be non-importable +} + +func (imp importer) Import(path string) (*types.Package, error) { + if p := imp.pkg.Prog.ImportedPackage(path); p != nil { + return p.Pkg, nil + } + if path == imp.pkg.Pkg.Path() { + return imp.pkg.Pkg, nil + } + return nil, fmt.Errorf("not found") // can't happen +} + +var testmainTmpl = template.Must(template.New("testmain").Parse(` +package main + +import "io" +import "os" +import "testing" +import p {{printf "%q" .Pkg.Pkg.Path}} + +{{if .Go18}} +type deps struct{} + +func (deps) MatchString(pat, str string) (bool, error) { return true, nil } +func (deps) StartCPUProfile(io.Writer) error { return nil } +func (deps) StopCPUProfile() {} +func (deps) WriteHeapProfile(io.Writer) error { return nil } +func (deps) WriteProfileTo(string, io.Writer, int) error { return nil } + +var match deps +{{else}} +func match(_, _ string) (bool, error) { return true, nil } +{{end}} + +func main() { + tests := []testing.InternalTest{ +{{range .Tests}} + { {{printf "%q" .Name}}, p.{{.Name}} }, +{{end}} + } + benchmarks := []testing.InternalBenchmark{ +{{range .Benchmarks}} + { {{printf "%q" .Name}}, p.{{.Name}} }, +{{end}} + } + examples := []testing.InternalExample{ +{{range .Examples}} + {Name: {{printf "%q" .Name}}, F: p.{{.Name}}}, +{{end}} + } + m := testing.MainStart(match, tests, benchmarks, examples) +{{with .Main}} + p.{{.Name}}(m) +{{else}} + os.Exit(m.Run()) +{{end}} +} + +`)) + +var examplesOnlyTmpl = template.Must(template.New("examples").Parse(` +package main + +import p {{printf "%q" .Pkg.Pkg.Path}} + +func main() { +{{range .Examples}} + p.{{.Name}}() +{{end}} +} +`)) diff --git a/vendor/honnef.co/go/tools/ssa/util.go b/vendor/honnef.co/go/tools/ssa/util.go new file mode 100644 index 0000000..317a013 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/util.go @@ -0,0 +1,121 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// This file defines a number of miscellaneous utility functions. + +import ( + "fmt" + "go/ast" + "go/token" + "go/types" + "io" + "os" + + "golang.org/x/tools/go/ast/astutil" +) + +//// AST utilities + +func unparen(e ast.Expr) ast.Expr { return astutil.Unparen(e) } + +// isBlankIdent returns true iff e is an Ident with name "_". +// They have no associated types.Object, and thus no type. +// +func isBlankIdent(e ast.Expr) bool { + id, ok := e.(*ast.Ident) + return ok && id.Name == "_" +} + +//// Type utilities. Some of these belong in go/types. + +// isPointer returns true for types whose underlying type is a pointer. +func isPointer(typ types.Type) bool { + _, ok := typ.Underlying().(*types.Pointer) + return ok +} + +func isInterface(T types.Type) bool { return types.IsInterface(T) } + +// deref returns a pointer's element type; otherwise it returns typ. +func deref(typ types.Type) types.Type { + if p, ok := typ.Underlying().(*types.Pointer); ok { + return p.Elem() + } + return typ +} + +// recvType returns the receiver type of method obj. +func recvType(obj *types.Func) types.Type { + return obj.Type().(*types.Signature).Recv().Type() +} + +// DefaultType returns the default "typed" type for an "untyped" type; +// it returns the incoming type for all other types. The default type +// for untyped nil is untyped nil. +// +// Exported to ssa/interp. +// +// TODO(gri): this is a copy of go/types.defaultType; export that function. +// +func DefaultType(typ types.Type) types.Type { + if t, ok := typ.(*types.Basic); ok { + k := t.Kind() + switch k { + case types.UntypedBool: + k = types.Bool + case types.UntypedInt: + k = types.Int + case types.UntypedRune: + k = types.Rune + case types.UntypedFloat: + k = types.Float64 + case types.UntypedComplex: + k = types.Complex128 + case types.UntypedString: + k = types.String + } + typ = types.Typ[k] + } + return typ +} + +// logStack prints the formatted "start" message to stderr and +// returns a closure that prints the corresponding "end" message. +// Call using 'defer logStack(...)()' to show builder stack on panic. +// Don't forget trailing parens! +// +func logStack(format string, args ...interface{}) func() { + msg := fmt.Sprintf(format, args...) + io.WriteString(os.Stderr, msg) + io.WriteString(os.Stderr, "\n") + return func() { + io.WriteString(os.Stderr, msg) + io.WriteString(os.Stderr, " end\n") + } +} + +// newVar creates a 'var' for use in a types.Tuple. +func newVar(name string, typ types.Type) *types.Var { + return types.NewParam(token.NoPos, nil, name, typ) +} + +// anonVar creates an anonymous 'var' for use in a types.Tuple. +func anonVar(typ types.Type) *types.Var { + return newVar("", typ) +} + +var lenResults = types.NewTuple(anonVar(tInt)) + +// makeLen returns the len builtin specialized to type func(T)int. +func makeLen(T types.Type) *Builtin { + lenParams := types.NewTuple(anonVar(T)) + return &Builtin{ + name: "len", + sig: types.NewSignature(nil, lenParams, lenResults, false), + } +} diff --git a/vendor/honnef.co/go/tools/ssa/wrappers.go b/vendor/honnef.co/go/tools/ssa/wrappers.go new file mode 100644 index 0000000..6ca01ab --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/wrappers.go @@ -0,0 +1,296 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.5 + +package ssa + +// This file defines synthesis of Functions that delegate to declared +// methods; they come in three kinds: +// +// (1) wrappers: methods that wrap declared methods, performing +// implicit pointer indirections and embedded field selections. +// +// (2) thunks: funcs that wrap declared methods. Like wrappers, +// thunks perform indirections and field selections. The thunk's +// first parameter is used as the receiver for the method call. +// +// (3) bounds: funcs that wrap declared methods. The bound's sole +// free variable, supplied by a closure, is used as the receiver +// for the method call. No indirections or field selections are +// performed since they can be done before the call. + +import ( + "fmt" + + "go/types" +) + +// -- wrappers ----------------------------------------------------------- + +// makeWrapper returns a synthetic method that delegates to the +// declared method denoted by meth.Obj(), first performing any +// necessary pointer indirections or field selections implied by meth. +// +// The resulting method's receiver type is meth.Recv(). +// +// This function is versatile but quite subtle! Consider the +// following axes of variation when making changes: +// - optional receiver indirection +// - optional implicit field selections +// - meth.Obj() may denote a concrete or an interface method +// - the result may be a thunk or a wrapper. +// +// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu) +// +func makeWrapper(prog *Program, sel *types.Selection) *Function { + obj := sel.Obj().(*types.Func) // the declared function + sig := sel.Type().(*types.Signature) // type of this wrapper + + var recv *types.Var // wrapper's receiver or thunk's params[0] + name := obj.Name() + var description string + var start int // first regular param + if sel.Kind() == types.MethodExpr { + name += "$thunk" + description = "thunk" + recv = sig.Params().At(0) + start = 1 + } else { + description = "wrapper" + recv = sig.Recv() + } + + description = fmt.Sprintf("%s for %s", description, sel.Obj()) + if prog.mode&LogSource != 0 { + defer logStack("make %s to (%s)", description, recv.Type())() + } + fn := &Function{ + name: name, + method: sel, + object: obj, + Signature: sig, + Synthetic: description, + Prog: prog, + pos: obj.Pos(), + } + fn.startBody() + fn.addSpilledParam(recv) + createParams(fn, start) + + indices := sel.Index() + + var v Value = fn.Locals[0] // spilled receiver + if isPointer(sel.Recv()) { + v = emitLoad(fn, v) + + // For simple indirection wrappers, perform an informative nil-check: + // "value method (T).f called using nil *T pointer" + if len(indices) == 1 && !isPointer(recvType(obj)) { + var c Call + c.Call.Value = &Builtin{ + name: "ssa:wrapnilchk", + sig: types.NewSignature(nil, + types.NewTuple(anonVar(sel.Recv()), anonVar(tString), anonVar(tString)), + types.NewTuple(anonVar(sel.Recv())), false), + } + c.Call.Args = []Value{ + v, + stringConst(deref(sel.Recv()).String()), + stringConst(sel.Obj().Name()), + } + c.setType(v.Type()) + v = fn.emit(&c) + } + } + + // Invariant: v is a pointer, either + // value of *A receiver param, or + // address of A spilled receiver. + + // We use pointer arithmetic (FieldAddr possibly followed by + // Load) in preference to value extraction (Field possibly + // preceded by Load). + + v = emitImplicitSelections(fn, v, indices[:len(indices)-1]) + + // Invariant: v is a pointer, either + // value of implicit *C field, or + // address of implicit C field. + + var c Call + if r := recvType(obj); !isInterface(r) { // concrete method + if !isPointer(r) { + v = emitLoad(fn, v) + } + c.Call.Value = prog.declaredFunc(obj) + c.Call.Args = append(c.Call.Args, v) + } else { + c.Call.Method = obj + c.Call.Value = emitLoad(fn, v) + } + for _, arg := range fn.Params[1:] { + c.Call.Args = append(c.Call.Args, arg) + } + emitTailCall(fn, &c) + fn.finishBody() + return fn +} + +// createParams creates parameters for wrapper method fn based on its +// Signature.Params, which do not include the receiver. +// start is the index of the first regular parameter to use. +// +func createParams(fn *Function, start int) { + var last *Parameter + tparams := fn.Signature.Params() + for i, n := start, tparams.Len(); i < n; i++ { + last = fn.addParamObj(tparams.At(i)) + } + if fn.Signature.Variadic() { + last.typ = types.NewSlice(last.typ) + } +} + +// -- bounds ----------------------------------------------------------- + +// makeBound returns a bound method wrapper (or "bound"), a synthetic +// function that delegates to a concrete or interface method denoted +// by obj. The resulting function has no receiver, but has one free +// variable which will be used as the method's receiver in the +// tail-call. +// +// Use MakeClosure with such a wrapper to construct a bound method +// closure. e.g.: +// +// type T int or: type T interface { meth() } +// func (t T) meth() +// var t T +// f := t.meth +// f() // calls t.meth() +// +// f is a closure of a synthetic wrapper defined as if by: +// +// f := func() { return t.meth() } +// +// Unlike makeWrapper, makeBound need perform no indirection or field +// selections because that can be done before the closure is +// constructed. +// +// EXCLUSIVE_LOCKS_ACQUIRED(meth.Prog.methodsMu) +// +func makeBound(prog *Program, obj *types.Func) *Function { + prog.methodsMu.Lock() + defer prog.methodsMu.Unlock() + fn, ok := prog.bounds[obj] + if !ok { + description := fmt.Sprintf("bound method wrapper for %s", obj) + if prog.mode&LogSource != 0 { + defer logStack("%s", description)() + } + fn = &Function{ + name: obj.Name() + "$bound", + object: obj, + Signature: changeRecv(obj.Type().(*types.Signature), nil), // drop receiver + Synthetic: description, + Prog: prog, + pos: obj.Pos(), + } + + fv := &FreeVar{name: "recv", typ: recvType(obj), parent: fn} + fn.FreeVars = []*FreeVar{fv} + fn.startBody() + createParams(fn, 0) + var c Call + + if !isInterface(recvType(obj)) { // concrete + c.Call.Value = prog.declaredFunc(obj) + c.Call.Args = []Value{fv} + } else { + c.Call.Value = fv + c.Call.Method = obj + } + for _, arg := range fn.Params { + c.Call.Args = append(c.Call.Args, arg) + } + emitTailCall(fn, &c) + fn.finishBody() + + prog.bounds[obj] = fn + } + return fn +} + +// -- thunks ----------------------------------------------------------- + +// makeThunk returns a thunk, a synthetic function that delegates to a +// concrete or interface method denoted by sel.Obj(). The resulting +// function has no receiver, but has an additional (first) regular +// parameter. +// +// Precondition: sel.Kind() == types.MethodExpr. +// +// type T int or: type T interface { meth() } +// func (t T) meth() +// f := T.meth +// var t T +// f(t) // calls t.meth() +// +// f is a synthetic wrapper defined as if by: +// +// f := func(t T) { return t.meth() } +// +// TODO(adonovan): opt: currently the stub is created even when used +// directly in a function call: C.f(i, 0). This is less efficient +// than inlining the stub. +// +// EXCLUSIVE_LOCKS_ACQUIRED(meth.Prog.methodsMu) +// +func makeThunk(prog *Program, sel *types.Selection) *Function { + if sel.Kind() != types.MethodExpr { + panic(sel) + } + + key := selectionKey{ + kind: sel.Kind(), + recv: sel.Recv(), + obj: sel.Obj(), + index: fmt.Sprint(sel.Index()), + indirect: sel.Indirect(), + } + + prog.methodsMu.Lock() + defer prog.methodsMu.Unlock() + + // Canonicalize key.recv to avoid constructing duplicate thunks. + canonRecv, ok := prog.canon.At(key.recv).(types.Type) + if !ok { + canonRecv = key.recv + prog.canon.Set(key.recv, canonRecv) + } + key.recv = canonRecv + + fn, ok := prog.thunks[key] + if !ok { + fn = makeWrapper(prog, sel) + if fn.Signature.Recv() != nil { + panic(fn) // unexpected receiver + } + prog.thunks[key] = fn + } + return fn +} + +func changeRecv(s *types.Signature, recv *types.Var) *types.Signature { + return types.NewSignature(recv, s.Params(), s.Results(), s.Variadic()) +} + +// selectionKey is like types.Selection but a usable map key. +type selectionKey struct { + kind types.SelectionKind + recv types.Type // canonicalized via Program.canon + obj types.Object + index string + indirect bool +} diff --git a/vendor/honnef.co/go/tools/ssa/write.go b/vendor/honnef.co/go/tools/ssa/write.go new file mode 100644 index 0000000..89761a1 --- /dev/null +++ b/vendor/honnef.co/go/tools/ssa/write.go @@ -0,0 +1,5 @@ +package ssa + +func NewJump(parent *BasicBlock) *Jump { + return &Jump{anInstruction{parent}} +} diff --git a/vendor/honnef.co/go/tools/staticcheck/buildtag.go b/vendor/honnef.co/go/tools/staticcheck/buildtag.go new file mode 100644 index 0000000..27c31c0 --- /dev/null +++ b/vendor/honnef.co/go/tools/staticcheck/buildtag.go @@ -0,0 +1,21 @@ +package staticcheck + +import ( + "go/ast" + "strings" + + "honnef.co/go/tools/lint" +) + +func buildTags(f *ast.File) [][]string { + var out [][]string + for _, line := range strings.Split(lint.Preamble(f), "\n") { + if !strings.HasPrefix(line, "+build ") { + continue + } + line = strings.TrimSpace(strings.TrimPrefix(line, "+build ")) + fields := strings.Fields(line) + out = append(out, fields) + } + return out +} diff --git a/vendor/honnef.co/go/tools/staticcheck/lint.go b/vendor/honnef.co/go/tools/staticcheck/lint.go new file mode 100644 index 0000000..fdc395e --- /dev/null +++ b/vendor/honnef.co/go/tools/staticcheck/lint.go @@ -0,0 +1,2738 @@ +// Package staticcheck contains a linter for Go source code. +package staticcheck // import "honnef.co/go/tools/staticcheck" + +import ( + "fmt" + "go/ast" + "go/constant" + "go/token" + "go/types" + htmltemplate "html/template" + "net/http" + "regexp" + "sort" + "strconv" + "strings" + "sync" + texttemplate "text/template" + + "honnef.co/go/tools/deprecated" + "honnef.co/go/tools/functions" + "honnef.co/go/tools/internal/sharedcheck" + "honnef.co/go/tools/lint" + "honnef.co/go/tools/ssa" + "honnef.co/go/tools/staticcheck/vrp" + + "golang.org/x/tools/go/ast/astutil" +) + +func validRegexp(call *Call) { + arg := call.Args[0] + err := ValidateRegexp(arg.Value) + if err != nil { + arg.Invalid(err.Error()) + } +} + +type runeSlice []rune + +func (rs runeSlice) Len() int { return len(rs) } +func (rs runeSlice) Less(i int, j int) bool { return rs[i] < rs[j] } +func (rs runeSlice) Swap(i int, j int) { rs[i], rs[j] = rs[j], rs[i] } + +func utf8Cutset(call *Call) { + arg := call.Args[1] + if InvalidUTF8(arg.Value) { + arg.Invalid(MsgInvalidUTF8) + } +} + +func uniqueCutset(call *Call) { + arg := call.Args[1] + if !UniqueStringCutset(arg.Value) { + arg.Invalid(MsgNonUniqueCutset) + } +} + +func unmarshalPointer(name string, arg int) CallCheck { + return func(call *Call) { + if !Pointer(call.Args[arg].Value) { + call.Args[arg].Invalid(fmt.Sprintf("%s expects to unmarshal into a pointer, but the provided value is not a pointer", name)) + } + } +} + +func pointlessIntMath(call *Call) { + if ConvertedFromInt(call.Args[0].Value) { + call.Invalid(fmt.Sprintf("calling %s on a converted integer is pointless", lint.CallName(call.Instr.Common()))) + } +} + +func checkValidHostPort(arg int) CallCheck { + return func(call *Call) { + if !ValidHostPort(call.Args[arg].Value) { + call.Args[arg].Invalid(MsgInvalidHostPort) + } + } +} + +var ( + checkRegexpRules = map[string]CallCheck{ + "regexp.MustCompile": validRegexp, + "regexp.Compile": validRegexp, + } + + checkTimeParseRules = map[string]CallCheck{ + "time.Parse": func(call *Call) { + arg := call.Args[0] + err := ValidateTimeLayout(arg.Value) + if err != nil { + arg.Invalid(err.Error()) + } + }, + } + + checkEncodingBinaryRules = map[string]CallCheck{ + "encoding/binary.Write": func(call *Call) { + arg := call.Args[2] + if !CanBinaryMarshal(call.Job, arg.Value) { + arg.Invalid(fmt.Sprintf("value of type %s cannot be used with binary.Write", arg.Value.Value.Type())) + } + }, + } + + checkURLsRules = map[string]CallCheck{ + "net/url.Parse": func(call *Call) { + arg := call.Args[0] + err := ValidateURL(arg.Value) + if err != nil { + arg.Invalid(err.Error()) + } + }, + } + + checkSyncPoolValueRules = map[string]CallCheck{ + "(*sync.Pool).Put": func(call *Call) { + arg := call.Args[0] + typ := arg.Value.Value.Type() + if !lint.IsPointerLike(typ) { + arg.Invalid("argument should be pointer-like to avoid allocations") + } + }, + } + + checkRegexpFindAllRules = map[string]CallCheck{ + "(*regexp.Regexp).FindAll": RepeatZeroTimes("a FindAll method", 1), + "(*regexp.Regexp).FindAllIndex": RepeatZeroTimes("a FindAll method", 1), + "(*regexp.Regexp).FindAllString": RepeatZeroTimes("a FindAll method", 1), + "(*regexp.Regexp).FindAllStringIndex": RepeatZeroTimes("a FindAll method", 1), + "(*regexp.Regexp).FindAllStringSubmatch": RepeatZeroTimes("a FindAll method", 1), + "(*regexp.Regexp).FindAllStringSubmatchIndex": RepeatZeroTimes("a FindAll method", 1), + "(*regexp.Regexp).FindAllSubmatch": RepeatZeroTimes("a FindAll method", 1), + "(*regexp.Regexp).FindAllSubmatchIndex": RepeatZeroTimes("a FindAll method", 1), + } + + checkUTF8CutsetRules = map[string]CallCheck{ + "strings.IndexAny": utf8Cutset, + "strings.LastIndexAny": utf8Cutset, + "strings.ContainsAny": utf8Cutset, + "strings.Trim": utf8Cutset, + "strings.TrimLeft": utf8Cutset, + "strings.TrimRight": utf8Cutset, + } + + checkUniqueCutsetRules = map[string]CallCheck{ + "strings.Trim": uniqueCutset, + "strings.TrimLeft": uniqueCutset, + "strings.TrimRight": uniqueCutset, + } + + checkUnmarshalPointerRules = map[string]CallCheck{ + "encoding/xml.Unmarshal": unmarshalPointer("xml.Unmarshal", 1), + "(*encoding/xml.Decoder).Decode": unmarshalPointer("Decode", 0), + "encoding/json.Unmarshal": unmarshalPointer("json.Unmarshal", 1), + "(*encoding/json.Decoder).Decode": unmarshalPointer("Decode", 0), + } + + checkUnbufferedSignalChanRules = map[string]CallCheck{ + "os/signal.Notify": func(call *Call) { + arg := call.Args[0] + if UnbufferedChannel(arg.Value) { + arg.Invalid("the channel used with signal.Notify should be buffered") + } + }, + } + + checkMathIntRules = map[string]CallCheck{ + "math.Ceil": pointlessIntMath, + "math.Floor": pointlessIntMath, + "math.IsNaN": pointlessIntMath, + "math.Trunc": pointlessIntMath, + "math.IsInf": pointlessIntMath, + } + + checkStringsReplaceZeroRules = map[string]CallCheck{ + "strings.Replace": RepeatZeroTimes("strings.Replace", 3), + "bytes.Replace": RepeatZeroTimes("bytes.Replace", 3), + } + + checkListenAddressRules = map[string]CallCheck{ + "net/http.ListenAndServe": checkValidHostPort(0), + "net/http.ListenAndServeTLS": checkValidHostPort(0), + } + + checkBytesEqualIPRules = map[string]CallCheck{ + "bytes.Equal": func(call *Call) { + if ConvertedFrom(call.Args[0].Value, "net.IP") && ConvertedFrom(call.Args[1].Value, "net.IP") { + call.Invalid("use net.IP.Equal to compare net.IPs, not bytes.Equal") + } + }, + } + + checkRegexpMatchLoopRules = map[string]CallCheck{ + "regexp.Match": loopedRegexp("regexp.Match"), + "regexp.MatchReader": loopedRegexp("regexp.MatchReader"), + "regexp.MatchString": loopedRegexp("regexp.MatchString"), + } +) + +type Checker struct { + CheckGenerated bool + funcDescs *functions.Descriptions + deprecatedObjs map[types.Object]string + nodeFns map[ast.Node]*ssa.Function +} + +func NewChecker() *Checker { + return &Checker{} +} + +func (*Checker) Name() string { return "staticcheck" } +func (*Checker) Prefix() string { return "SA" } + +func (c *Checker) Funcs() map[string]lint.Func { + return map[string]lint.Func{ + "SA1000": c.callChecker(checkRegexpRules), + "SA1001": c.CheckTemplate, + "SA1002": c.callChecker(checkTimeParseRules), + "SA1003": c.callChecker(checkEncodingBinaryRules), + "SA1004": c.CheckTimeSleepConstant, + "SA1005": c.CheckExec, + "SA1006": c.CheckUnsafePrintf, + "SA1007": c.callChecker(checkURLsRules), + "SA1008": c.CheckCanonicalHeaderKey, + "SA1009": nil, + "SA1010": c.callChecker(checkRegexpFindAllRules), + "SA1011": c.callChecker(checkUTF8CutsetRules), + "SA1012": c.CheckNilContext, + "SA1013": c.CheckSeeker, + "SA1014": c.callChecker(checkUnmarshalPointerRules), + "SA1015": c.CheckLeakyTimeTick, + "SA1016": c.CheckUntrappableSignal, + "SA1017": c.callChecker(checkUnbufferedSignalChanRules), + "SA1018": c.callChecker(checkStringsReplaceZeroRules), + "SA1019": c.CheckDeprecated, + "SA1020": c.callChecker(checkListenAddressRules), + "SA1021": c.callChecker(checkBytesEqualIPRules), + "SA1022": nil, + "SA1023": c.CheckWriterBufferModified, + "SA1024": c.callChecker(checkUniqueCutsetRules), + + "SA2000": c.CheckWaitgroupAdd, + "SA2001": c.CheckEmptyCriticalSection, + "SA2002": c.CheckConcurrentTesting, + "SA2003": c.CheckDeferLock, + + "SA3000": c.CheckTestMainExit, + "SA3001": c.CheckBenchmarkN, + + "SA4000": c.CheckLhsRhsIdentical, + "SA4001": c.CheckIneffectiveCopy, + "SA4002": c.CheckDiffSizeComparison, + "SA4003": c.CheckUnsignedComparison, + "SA4004": c.CheckIneffectiveLoop, + "SA4005": nil, + "SA4006": c.CheckUnreadVariableValues, + // "SA4007": c.CheckPredeterminedBooleanExprs, + "SA4007": nil, + "SA4008": c.CheckLoopCondition, + "SA4009": c.CheckArgOverwritten, + "SA4010": c.CheckIneffectiveAppend, + "SA4011": c.CheckScopedBreak, + "SA4012": c.CheckNaNComparison, + "SA4013": c.CheckDoubleNegation, + "SA4014": c.CheckRepeatedIfElse, + "SA4015": c.callChecker(checkMathIntRules), + "SA4016": c.CheckSillyBitwiseOps, + "SA4017": c.CheckPureFunctions, + "SA4018": c.CheckSelfAssignment, + "SA4019": c.CheckDuplicateBuildConstraints, + + "SA5000": c.CheckNilMaps, + "SA5001": c.CheckEarlyDefer, + "SA5002": c.CheckInfiniteEmptyLoop, + "SA5003": c.CheckDeferInInfiniteLoop, + "SA5004": c.CheckLoopEmptyDefault, + "SA5005": c.CheckCyclicFinalizer, + // "SA5006": c.CheckSliceOutOfBounds, + "SA5007": c.CheckInfiniteRecursion, + + "SA6000": c.callChecker(checkRegexpMatchLoopRules), + "SA6001": c.CheckMapBytesKey, + "SA6002": c.callChecker(checkSyncPoolValueRules), + "SA6003": c.CheckRangeStringRunes, + "SA6004": nil, + + "SA9000": nil, + "SA9001": c.CheckDubiousDeferInChannelRangeLoop, + "SA9002": c.CheckNonOctalFileMode, + "SA9003": c.CheckEmptyBranch, + } +} + +func (c *Checker) filterGenerated(files []*ast.File) []*ast.File { + if c.CheckGenerated { + return files + } + var out []*ast.File + for _, f := range files { + if !lint.IsGenerated(f) { + out = append(out, f) + } + } + return out +} + +func (c *Checker) deprecateObject(m map[types.Object]string, prog *lint.Program, obj types.Object) { + if obj.Pkg() == nil { + return + } + + f := prog.File(obj) + if f == nil { + return + } + msg := c.deprecationMessage(f, prog.Prog.Fset, obj) + if msg != "" { + m[obj] = msg + } +} + +func (c *Checker) Init(prog *lint.Program) { + wg := &sync.WaitGroup{} + wg.Add(3) + go func() { + c.funcDescs = functions.NewDescriptions(prog.SSA) + for _, fn := range prog.AllFunctions { + if fn.Blocks != nil { + applyStdlibKnowledge(fn) + ssa.OptimizeBlocks(fn) + } + } + wg.Done() + }() + + go func() { + c.nodeFns = lint.NodeFns(prog.Packages) + wg.Done() + }() + + go func() { + c.deprecatedObjs = map[types.Object]string{} + for _, ssapkg := range prog.SSA.AllPackages() { + ssapkg := ssapkg + for _, member := range ssapkg.Members { + obj := member.Object() + if obj == nil { + continue + } + c.deprecateObject(c.deprecatedObjs, prog, obj) + if typ, ok := obj.Type().(*types.Named); ok { + for i := 0; i < typ.NumMethods(); i++ { + meth := typ.Method(i) + c.deprecateObject(c.deprecatedObjs, prog, meth) + } + + if iface, ok := typ.Underlying().(*types.Interface); ok { + for i := 0; i < iface.NumExplicitMethods(); i++ { + meth := iface.ExplicitMethod(i) + c.deprecateObject(c.deprecatedObjs, prog, meth) + } + } + } + if typ, ok := obj.Type().Underlying().(*types.Struct); ok { + n := typ.NumFields() + for i := 0; i < n; i++ { + // FIXME(dh): This code will not find deprecated + // fields in anonymous structs. + field := typ.Field(i) + c.deprecateObject(c.deprecatedObjs, prog, field) + } + } + } + } + wg.Done() + }() + + wg.Wait() +} + +func (c *Checker) deprecationMessage(file *ast.File, fset *token.FileSet, obj types.Object) (message string) { + pos := obj.Pos() + path, _ := astutil.PathEnclosingInterval(file, pos, pos) + if len(path) <= 2 { + return "" + } + var docs []*ast.CommentGroup + switch n := path[1].(type) { + case *ast.FuncDecl: + docs = append(docs, n.Doc) + case *ast.Field: + docs = append(docs, n.Doc) + case *ast.ValueSpec: + docs = append(docs, n.Doc) + if len(path) >= 3 { + if n, ok := path[2].(*ast.GenDecl); ok { + docs = append(docs, n.Doc) + } + } + case *ast.TypeSpec: + docs = append(docs, n.Doc) + if len(path) >= 3 { + if n, ok := path[2].(*ast.GenDecl); ok { + docs = append(docs, n.Doc) + } + } + default: + return "" + } + + for _, doc := range docs { + if doc == nil { + continue + } + parts := strings.Split(doc.Text(), "\n\n") + last := parts[len(parts)-1] + if !strings.HasPrefix(last, "Deprecated: ") { + continue + } + alt := last[len("Deprecated: "):] + alt = strings.Replace(alt, "\n", " ", -1) + return alt + } + return "" +} + +func (c *Checker) isInLoop(b *ssa.BasicBlock) bool { + sets := c.funcDescs.Get(b.Parent()).Loops + for _, set := range sets { + if set[b] { + return true + } + } + return false +} + +func applyStdlibKnowledge(fn *ssa.Function) { + if len(fn.Blocks) == 0 { + return + } + + // comma-ok receiving from a time.Tick channel will never return + // ok == false, so any branching on the value of ok can be + // replaced with an unconditional jump. This will primarily match + // `for range time.Tick(x)` loops, but it can also match + // user-written code. + for _, block := range fn.Blocks { + if len(block.Instrs) < 3 { + continue + } + if len(block.Succs) != 2 { + continue + } + var instrs []*ssa.Instruction + for i, ins := range block.Instrs { + if _, ok := ins.(*ssa.DebugRef); ok { + continue + } + instrs = append(instrs, &block.Instrs[i]) + } + + for i, ins := range instrs { + unop, ok := (*ins).(*ssa.UnOp) + if !ok || unop.Op != token.ARROW { + continue + } + call, ok := unop.X.(*ssa.Call) + if !ok { + continue + } + if !lint.IsCallTo(call.Common(), "time.Tick") { + continue + } + ex, ok := (*instrs[i+1]).(*ssa.Extract) + if !ok || ex.Tuple != unop || ex.Index != 1 { + continue + } + + ifstmt, ok := (*instrs[i+2]).(*ssa.If) + if !ok || ifstmt.Cond != ex { + continue + } + + *instrs[i+2] = ssa.NewJump(block) + succ := block.Succs[1] + block.Succs = block.Succs[0:1] + succ.RemovePred(block) + } + } +} + +func hasType(j *lint.Job, expr ast.Expr, name string) bool { + return types.TypeString(j.Program.Info.TypeOf(expr), nil) == name +} + +func (c *Checker) CheckUntrappableSignal(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + if !j.IsCallToAnyAST(call, + "os/signal.Ignore", "os/signal.Notify", "os/signal.Reset") { + return true + } + for _, arg := range call.Args { + if conv, ok := arg.(*ast.CallExpr); ok && isName(j, conv.Fun, "os.Signal") { + arg = conv.Args[0] + } + + if isName(j, arg, "os.Kill") || isName(j, arg, "syscall.SIGKILL") { + j.Errorf(arg, "%s cannot be trapped (did you mean syscall.SIGTERM?)", j.Render(arg)) + } + if isName(j, arg, "syscall.SIGSTOP") { + j.Errorf(arg, "%s signal cannot be trapped", j.Render(arg)) + } + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckTemplate(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + var kind string + if j.IsCallToAST(call, "(*text/template.Template).Parse") { + kind = "text" + } else if j.IsCallToAST(call, "(*html/template.Template).Parse") { + kind = "html" + } else { + return true + } + sel := call.Fun.(*ast.SelectorExpr) + if !j.IsCallToAST(sel.X, "text/template.New") && + !j.IsCallToAST(sel.X, "html/template.New") { + // TODO(dh): this is a cheap workaround for templates with + // different delims. A better solution with less false + // negatives would use data flow analysis to see where the + // template comes from and where it has been + return true + } + s, ok := j.ExprToString(call.Args[0]) + if !ok { + return true + } + var err error + switch kind { + case "text": + _, err = texttemplate.New("").Parse(s) + case "html": + _, err = htmltemplate.New("").Parse(s) + } + if err != nil { + // TODO(dominikh): whitelist other parse errors, if any + if strings.Contains(err.Error(), "unexpected") { + j.Errorf(call.Args[0], "%s", err) + } + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckTimeSleepConstant(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + if !j.IsCallToAST(call, "time.Sleep") { + return true + } + lit, ok := call.Args[0].(*ast.BasicLit) + if !ok { + return true + } + n, err := strconv.Atoi(lit.Value) + if err != nil { + return true + } + if n == 0 || n > 120 { + // time.Sleep(0) is a seldomly used pattern in concurrency + // tests. >120 might be intentional. 120 was chosen + // because the user could've meant 2 minutes. + return true + } + recommendation := "time.Sleep(time.Nanosecond)" + if n != 1 { + recommendation = fmt.Sprintf("time.Sleep(%d * time.Nanosecond)", n) + } + j.Errorf(call.Args[0], "sleeping for %d nanoseconds is probably a bug. Be explicit if it isn't: %s", n, recommendation) + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckWaitgroupAdd(j *lint.Job) { + fn := func(node ast.Node) bool { + g, ok := node.(*ast.GoStmt) + if !ok { + return true + } + fun, ok := g.Call.Fun.(*ast.FuncLit) + if !ok { + return true + } + if len(fun.Body.List) == 0 { + return true + } + stmt, ok := fun.Body.List[0].(*ast.ExprStmt) + if !ok { + return true + } + call, ok := stmt.X.(*ast.CallExpr) + if !ok { + return true + } + sel, ok := call.Fun.(*ast.SelectorExpr) + if !ok { + return true + } + fn, ok := j.Program.Info.ObjectOf(sel.Sel).(*types.Func) + if !ok { + return true + } + if fn.FullName() == "(*sync.WaitGroup).Add" { + j.Errorf(sel, "should call %s before starting the goroutine to avoid a race", + j.Render(stmt)) + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckInfiniteEmptyLoop(j *lint.Job) { + fn := func(node ast.Node) bool { + loop, ok := node.(*ast.ForStmt) + if !ok || len(loop.Body.List) != 0 || loop.Post != nil { + return true + } + + if loop.Init != nil { + // TODO(dh): this isn't strictly necessary, it just makes + // the check easier. + return true + } + // An empty loop is bad news in two cases: 1) The loop has no + // condition. In that case, it's just a loop that spins + // forever and as fast as it can, keeping a core busy. 2) The + // loop condition only consists of variable or field reads and + // operators on those. The only way those could change their + // value is with unsynchronised access, which constitutes a + // data race. + // + // If the condition contains any function calls, its behaviour + // is dynamic and the loop might terminate. Similarly for + // channel receives. + + if loop.Cond != nil && hasSideEffects(loop.Cond) { + return true + } + + j.Errorf(loop, "this loop will spin, using 100%% CPU") + if loop.Cond != nil { + j.Errorf(loop, "loop condition never changes or has a race condition") + } + + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckDeferInInfiniteLoop(j *lint.Job) { + fn := func(node ast.Node) bool { + mightExit := false + var defers []ast.Stmt + loop, ok := node.(*ast.ForStmt) + if !ok || loop.Cond != nil { + return true + } + fn2 := func(node ast.Node) bool { + switch stmt := node.(type) { + case *ast.ReturnStmt: + mightExit = true + case *ast.BranchStmt: + // TODO(dominikh): if this sees a break in a switch or + // select, it doesn't check if it breaks the loop or + // just the select/switch. This causes some false + // negatives. + if stmt.Tok == token.BREAK { + mightExit = true + } + case *ast.DeferStmt: + defers = append(defers, stmt) + case *ast.FuncLit: + // Don't look into function bodies + return false + } + return true + } + ast.Inspect(loop.Body, fn2) + if mightExit { + return true + } + for _, stmt := range defers { + j.Errorf(stmt, "defers in this infinite loop will never run") + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckDubiousDeferInChannelRangeLoop(j *lint.Job) { + fn := func(node ast.Node) bool { + loop, ok := node.(*ast.RangeStmt) + if !ok { + return true + } + typ := j.Program.Info.TypeOf(loop.X) + _, ok = typ.Underlying().(*types.Chan) + if !ok { + return true + } + fn2 := func(node ast.Node) bool { + switch stmt := node.(type) { + case *ast.DeferStmt: + j.Errorf(stmt, "defers in this range loop won't run unless the channel gets closed") + case *ast.FuncLit: + // Don't look into function bodies + return false + } + return true + } + ast.Inspect(loop.Body, fn2) + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckTestMainExit(j *lint.Job) { + fn := func(node ast.Node) bool { + if !isTestMain(j, node) { + return true + } + + arg := j.Program.Info.ObjectOf(node.(*ast.FuncDecl).Type.Params.List[0].Names[0]) + callsRun := false + fn2 := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + sel, ok := call.Fun.(*ast.SelectorExpr) + if !ok { + return true + } + ident, ok := sel.X.(*ast.Ident) + if !ok { + return true + } + if arg != j.Program.Info.ObjectOf(ident) { + return true + } + if sel.Sel.Name == "Run" { + callsRun = true + return false + } + return true + } + ast.Inspect(node.(*ast.FuncDecl).Body, fn2) + + callsExit := false + fn3 := func(node ast.Node) bool { + if j.IsCallToAST(node, "os.Exit") { + callsExit = true + return false + } + return true + } + ast.Inspect(node.(*ast.FuncDecl).Body, fn3) + if !callsExit && callsRun { + j.Errorf(node, "TestMain should call os.Exit to set exit code") + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func isTestMain(j *lint.Job, node ast.Node) bool { + decl, ok := node.(*ast.FuncDecl) + if !ok { + return false + } + if decl.Name.Name != "TestMain" { + return false + } + if len(decl.Type.Params.List) != 1 { + return false + } + arg := decl.Type.Params.List[0] + if len(arg.Names) != 1 { + return false + } + typ := j.Program.Info.TypeOf(arg.Type) + return typ != nil && typ.String() == "*testing.M" +} + +func (c *Checker) CheckExec(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + if !j.IsCallToAST(call, "os/exec.Command") { + return true + } + val, ok := j.ExprToString(call.Args[0]) + if !ok { + return true + } + if !strings.Contains(val, " ") || strings.Contains(val, `\`) || strings.Contains(val, "/") { + return true + } + j.Errorf(call.Args[0], "first argument to exec.Command looks like a shell command, but a program name or path are expected") + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckLoopEmptyDefault(j *lint.Job) { + fn := func(node ast.Node) bool { + loop, ok := node.(*ast.ForStmt) + if !ok || len(loop.Body.List) != 1 || loop.Cond != nil || loop.Init != nil { + return true + } + sel, ok := loop.Body.List[0].(*ast.SelectStmt) + if !ok { + return true + } + for _, c := range sel.Body.List { + if comm, ok := c.(*ast.CommClause); ok && comm.Comm == nil && len(comm.Body) == 0 { + j.Errorf(comm, "should not have an empty default case in a for+select loop. The loop will spin.") + } + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckLhsRhsIdentical(j *lint.Job) { + fn := func(node ast.Node) bool { + op, ok := node.(*ast.BinaryExpr) + if !ok { + return true + } + switch op.Op { + case token.EQL, token.NEQ: + if basic, ok := j.Program.Info.TypeOf(op.X).(*types.Basic); ok { + if kind := basic.Kind(); kind == types.Float32 || kind == types.Float64 { + // f == f and f != f might be used to check for NaN + return true + } + } + case token.SUB, token.QUO, token.AND, token.REM, token.OR, token.XOR, token.AND_NOT, + token.LAND, token.LOR, token.LSS, token.GTR, token.LEQ, token.GEQ: + default: + // For some ops, such as + and *, it can make sense to + // have identical operands + return true + } + + if j.Render(op.X) != j.Render(op.Y) { + return true + } + j.Errorf(op, "identical expressions on the left and right side of the '%s' operator", op.Op) + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckScopedBreak(j *lint.Job) { + fn := func(node ast.Node) bool { + var body *ast.BlockStmt + switch node := node.(type) { + case *ast.ForStmt: + body = node.Body + case *ast.RangeStmt: + body = node.Body + default: + return true + } + for _, stmt := range body.List { + var blocks [][]ast.Stmt + switch stmt := stmt.(type) { + case *ast.SwitchStmt: + for _, c := range stmt.Body.List { + blocks = append(blocks, c.(*ast.CaseClause).Body) + } + case *ast.SelectStmt: + for _, c := range stmt.Body.List { + blocks = append(blocks, c.(*ast.CommClause).Body) + } + default: + continue + } + + for _, body := range blocks { + if len(body) == 0 { + continue + } + lasts := []ast.Stmt{body[len(body)-1]} + // TODO(dh): unfold all levels of nested block + // statements, not just a single level if statement + if ifs, ok := lasts[0].(*ast.IfStmt); ok { + if len(ifs.Body.List) == 0 { + continue + } + lasts[0] = ifs.Body.List[len(ifs.Body.List)-1] + + if block, ok := ifs.Else.(*ast.BlockStmt); ok { + if len(block.List) != 0 { + lasts = append(lasts, block.List[len(block.List)-1]) + } + } + } + for _, last := range lasts { + branch, ok := last.(*ast.BranchStmt) + if !ok || branch.Tok != token.BREAK || branch.Label != nil { + continue + } + j.Errorf(branch, "ineffective break statement. Did you mean to break out of the outer loop?") + } + } + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckUnsafePrintf(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + if !j.IsCallToAnyAST(call, "fmt.Printf", "fmt.Sprintf", "log.Printf") { + return true + } + if len(call.Args) != 1 { + return true + } + switch call.Args[0].(type) { + case *ast.CallExpr, *ast.Ident: + default: + return true + } + j.Errorf(call.Args[0], "printf-style function with dynamic first argument and no further arguments should use print-style function instead") + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckEarlyDefer(j *lint.Job) { + fn := func(node ast.Node) bool { + block, ok := node.(*ast.BlockStmt) + if !ok { + return true + } + if len(block.List) < 2 { + return true + } + for i, stmt := range block.List { + if i == len(block.List)-1 { + break + } + assign, ok := stmt.(*ast.AssignStmt) + if !ok { + continue + } + if len(assign.Rhs) != 1 { + continue + } + if len(assign.Lhs) < 2 { + continue + } + if lhs, ok := assign.Lhs[len(assign.Lhs)-1].(*ast.Ident); ok && lhs.Name == "_" { + continue + } + call, ok := assign.Rhs[0].(*ast.CallExpr) + if !ok { + continue + } + sig, ok := j.Program.Info.TypeOf(call.Fun).(*types.Signature) + if !ok { + continue + } + if sig.Results().Len() < 2 { + continue + } + last := sig.Results().At(sig.Results().Len() - 1) + // FIXME(dh): check that it's error from universe, not + // another type of the same name + if last.Type().String() != "error" { + continue + } + lhs, ok := assign.Lhs[0].(*ast.Ident) + if !ok { + continue + } + def, ok := block.List[i+1].(*ast.DeferStmt) + if !ok { + continue + } + sel, ok := def.Call.Fun.(*ast.SelectorExpr) + if !ok { + continue + } + ident, ok := selectorX(sel).(*ast.Ident) + if !ok { + continue + } + if ident.Obj != lhs.Obj { + continue + } + if sel.Sel.Name != "Close" { + continue + } + j.Errorf(def, "should check returned error before deferring %s", j.Render(def.Call)) + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func selectorX(sel *ast.SelectorExpr) ast.Node { + switch x := sel.X.(type) { + case *ast.SelectorExpr: + return selectorX(x) + default: + return x + } +} + +func (c *Checker) CheckEmptyCriticalSection(j *lint.Job) { + // Initially it might seem like this check would be easier to + // implement in SSA. After all, we're only checking for two + // consecutive method calls. In reality, however, there may be any + // number of other instructions between the lock and unlock, while + // still constituting an empty critical section. For example, + // given `m.x().Lock(); m.x().Unlock()`, there will be a call to + // x(). In the AST-based approach, this has a tiny potential for a + // false positive (the second call to x might be doing work that + // is protected by the mutex). In an SSA-based approach, however, + // it would miss a lot of real bugs. + + mutexParams := func(s ast.Stmt) (x ast.Expr, funcName string, ok bool) { + expr, ok := s.(*ast.ExprStmt) + if !ok { + return nil, "", false + } + call, ok := expr.X.(*ast.CallExpr) + if !ok { + return nil, "", false + } + sel, ok := call.Fun.(*ast.SelectorExpr) + if !ok { + return nil, "", false + } + + fn, ok := j.Program.Info.ObjectOf(sel.Sel).(*types.Func) + if !ok { + return nil, "", false + } + sig := fn.Type().(*types.Signature) + if sig.Params().Len() != 0 || sig.Results().Len() != 0 { + return nil, "", false + } + + return sel.X, fn.Name(), true + } + + fn := func(node ast.Node) bool { + block, ok := node.(*ast.BlockStmt) + if !ok { + return true + } + if len(block.List) < 2 { + return true + } + for i := range block.List[:len(block.List)-1] { + sel1, method1, ok1 := mutexParams(block.List[i]) + sel2, method2, ok2 := mutexParams(block.List[i+1]) + + if !ok1 || !ok2 || j.Render(sel1) != j.Render(sel2) { + continue + } + if (method1 == "Lock" && method2 == "Unlock") || + (method1 == "RLock" && method2 == "RUnlock") { + j.Errorf(block.List[i+1], "empty critical section") + } + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +// cgo produces code like fn(&*_Cvar_kSomeCallbacks) which we don't +// want to flag. +var cgoIdent = regexp.MustCompile(`^_C(func|var)_.+$`) + +func (c *Checker) CheckIneffectiveCopy(j *lint.Job) { + fn := func(node ast.Node) bool { + if unary, ok := node.(*ast.UnaryExpr); ok { + if star, ok := unary.X.(*ast.StarExpr); ok && unary.Op == token.AND { + ident, ok := star.X.(*ast.Ident) + if !ok || !cgoIdent.MatchString(ident.Name) { + j.Errorf(unary, "&*x will be simplified to x. It will not copy x.") + } + } + } + + if star, ok := node.(*ast.StarExpr); ok { + if unary, ok := star.X.(*ast.UnaryExpr); ok && unary.Op == token.AND { + j.Errorf(star, "*&x will be simplified to x. It will not copy x.") + } + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckDiffSizeComparison(j *lint.Job) { + for _, ssafn := range j.Program.InitialFunctions { + for _, b := range ssafn.Blocks { + for _, ins := range b.Instrs { + binop, ok := ins.(*ssa.BinOp) + if !ok { + continue + } + if binop.Op != token.EQL && binop.Op != token.NEQ { + continue + } + _, ok1 := binop.X.(*ssa.Slice) + _, ok2 := binop.Y.(*ssa.Slice) + if !ok1 && !ok2 { + continue + } + r := c.funcDescs.Get(ssafn).Ranges + r1, ok1 := r.Get(binop.X).(vrp.StringInterval) + r2, ok2 := r.Get(binop.Y).(vrp.StringInterval) + if !ok1 || !ok2 { + continue + } + if r1.Length.Intersection(r2.Length).Empty() { + j.Errorf(binop, "comparing strings of different sizes for equality will always return false") + } + } + } + } +} + +func (c *Checker) CheckCanonicalHeaderKey(j *lint.Job) { + fn := func(node ast.Node) bool { + assign, ok := node.(*ast.AssignStmt) + if ok { + // TODO(dh): This risks missing some Header reads, for + // example in `h1["foo"] = h2["foo"]` – these edge + // cases are probably rare enough to ignore for now. + for _, expr := range assign.Lhs { + op, ok := expr.(*ast.IndexExpr) + if !ok { + continue + } + if hasType(j, op.X, "net/http.Header") { + return false + } + } + return true + } + op, ok := node.(*ast.IndexExpr) + if !ok { + return true + } + if !hasType(j, op.X, "net/http.Header") { + return true + } + s, ok := j.ExprToString(op.Index) + if !ok { + return true + } + if s == http.CanonicalHeaderKey(s) { + return true + } + j.Errorf(op, "keys in http.Header are canonicalized, %q is not canonical; fix the constant or use http.CanonicalHeaderKey", s) + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckBenchmarkN(j *lint.Job) { + fn := func(node ast.Node) bool { + assign, ok := node.(*ast.AssignStmt) + if !ok { + return true + } + if len(assign.Lhs) != 1 || len(assign.Rhs) != 1 { + return true + } + sel, ok := assign.Lhs[0].(*ast.SelectorExpr) + if !ok { + return true + } + if sel.Sel.Name != "N" { + return true + } + if !hasType(j, sel.X, "*testing.B") { + return true + } + j.Errorf(assign, "should not assign to %s", j.Render(sel)) + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckUnreadVariableValues(j *lint.Job) { + fn := func(node ast.Node) bool { + switch node.(type) { + case *ast.FuncDecl, *ast.FuncLit: + default: + return true + } + + ssafn := c.nodeFns[node] + if ssafn == nil { + return true + } + if lint.IsExample(ssafn) { + return true + } + ast.Inspect(node, func(node ast.Node) bool { + assign, ok := node.(*ast.AssignStmt) + if !ok { + return true + } + if len(assign.Lhs) > 1 && len(assign.Rhs) == 1 { + // Either a function call with multiple return values, + // or a comma-ok assignment + + val, _ := ssafn.ValueForExpr(assign.Rhs[0]) + if val == nil { + return true + } + refs := val.Referrers() + if refs == nil { + return true + } + for _, ref := range *refs { + ex, ok := ref.(*ssa.Extract) + if !ok { + continue + } + exrefs := ex.Referrers() + if exrefs == nil { + continue + } + if len(lint.FilterDebug(*exrefs)) == 0 { + lhs := assign.Lhs[ex.Index] + if ident, ok := lhs.(*ast.Ident); !ok || ok && ident.Name == "_" { + continue + } + j.Errorf(lhs, "this value of %s is never used", lhs) + } + } + return true + } + for i, lhs := range assign.Lhs { + rhs := assign.Rhs[i] + if ident, ok := lhs.(*ast.Ident); !ok || ok && ident.Name == "_" { + continue + } + val, _ := ssafn.ValueForExpr(rhs) + if val == nil { + continue + } + + refs := val.Referrers() + if refs == nil { + // TODO investigate why refs can be nil + return true + } + if len(lint.FilterDebug(*refs)) == 0 { + j.Errorf(lhs, "this value of %s is never used", lhs) + } + } + return true + }) + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckPredeterminedBooleanExprs(j *lint.Job) { + for _, ssafn := range j.Program.InitialFunctions { + for _, block := range ssafn.Blocks { + for _, ins := range block.Instrs { + ssabinop, ok := ins.(*ssa.BinOp) + if !ok { + continue + } + switch ssabinop.Op { + case token.GTR, token.LSS, token.EQL, token.NEQ, token.LEQ, token.GEQ: + default: + continue + } + + xs, ok1 := consts(ssabinop.X, nil, nil) + ys, ok2 := consts(ssabinop.Y, nil, nil) + if !ok1 || !ok2 || len(xs) == 0 || len(ys) == 0 { + continue + } + + trues := 0 + for _, x := range xs { + for _, y := range ys { + if x.Value == nil { + if y.Value == nil { + trues++ + } + continue + } + if constant.Compare(x.Value, ssabinop.Op, y.Value) { + trues++ + } + } + } + b := trues != 0 + if trues == 0 || trues == len(xs)*len(ys) { + j.Errorf(ssabinop, "binary expression is always %t for all possible values (%s %s %s)", + b, xs, ssabinop.Op, ys) + } + } + } + } +} + +func (c *Checker) CheckNilMaps(j *lint.Job) { + for _, ssafn := range j.Program.InitialFunctions { + for _, block := range ssafn.Blocks { + for _, ins := range block.Instrs { + mu, ok := ins.(*ssa.MapUpdate) + if !ok { + continue + } + c, ok := mu.Map.(*ssa.Const) + if !ok { + continue + } + if c.Value != nil { + continue + } + j.Errorf(mu, "assignment to nil map") + } + } + } +} + +func (c *Checker) CheckUnsignedComparison(j *lint.Job) { + fn := func(node ast.Node) bool { + expr, ok := node.(*ast.BinaryExpr) + if !ok { + return true + } + tx := j.Program.Info.TypeOf(expr.X) + basic, ok := tx.Underlying().(*types.Basic) + if !ok { + return true + } + if (basic.Info() & types.IsUnsigned) == 0 { + return true + } + lit, ok := expr.Y.(*ast.BasicLit) + if !ok || lit.Value != "0" { + return true + } + switch expr.Op { + case token.GEQ: + j.Errorf(expr, "unsigned values are always >= 0") + case token.LSS: + j.Errorf(expr, "unsigned values are never < 0") + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func consts(val ssa.Value, out []*ssa.Const, visitedPhis map[string]bool) ([]*ssa.Const, bool) { + if visitedPhis == nil { + visitedPhis = map[string]bool{} + } + var ok bool + switch val := val.(type) { + case *ssa.Phi: + if visitedPhis[val.Name()] { + break + } + visitedPhis[val.Name()] = true + vals := val.Operands(nil) + for _, phival := range vals { + out, ok = consts(*phival, out, visitedPhis) + if !ok { + return nil, false + } + } + case *ssa.Const: + out = append(out, val) + case *ssa.Convert: + out, ok = consts(val.X, out, visitedPhis) + if !ok { + return nil, false + } + default: + return nil, false + } + if len(out) < 2 { + return out, true + } + uniq := []*ssa.Const{out[0]} + for _, val := range out[1:] { + if val.Value == uniq[len(uniq)-1].Value { + continue + } + uniq = append(uniq, val) + } + return uniq, true +} + +func (c *Checker) CheckLoopCondition(j *lint.Job) { + fn := func(node ast.Node) bool { + loop, ok := node.(*ast.ForStmt) + if !ok { + return true + } + if loop.Init == nil || loop.Cond == nil || loop.Post == nil { + return true + } + init, ok := loop.Init.(*ast.AssignStmt) + if !ok || len(init.Lhs) != 1 || len(init.Rhs) != 1 { + return true + } + cond, ok := loop.Cond.(*ast.BinaryExpr) + if !ok { + return true + } + x, ok := cond.X.(*ast.Ident) + if !ok { + return true + } + lhs, ok := init.Lhs[0].(*ast.Ident) + if !ok { + return true + } + if x.Obj != lhs.Obj { + return true + } + if _, ok := loop.Post.(*ast.IncDecStmt); !ok { + return true + } + + ssafn := c.nodeFns[cond] + if ssafn == nil { + return true + } + v, isAddr := ssafn.ValueForExpr(cond.X) + if v == nil || isAddr { + return true + } + switch v := v.(type) { + case *ssa.Phi: + ops := v.Operands(nil) + if len(ops) != 2 { + return true + } + _, ok := (*ops[0]).(*ssa.Const) + if !ok { + return true + } + sigma, ok := (*ops[1]).(*ssa.Sigma) + if !ok { + return true + } + if sigma.X != v { + return true + } + case *ssa.UnOp: + return true + } + j.Errorf(cond, "variable in loop condition never changes") + + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckArgOverwritten(j *lint.Job) { + fn := func(node ast.Node) bool { + var typ *ast.FuncType + var body *ast.BlockStmt + switch fn := node.(type) { + case *ast.FuncDecl: + typ = fn.Type + body = fn.Body + case *ast.FuncLit: + typ = fn.Type + body = fn.Body + } + if body == nil { + return true + } + ssafn := c.nodeFns[node] + if ssafn == nil { + return true + } + if len(typ.Params.List) == 0 { + return true + } + for _, field := range typ.Params.List { + for _, arg := range field.Names { + obj := j.Program.Info.ObjectOf(arg) + var ssaobj *ssa.Parameter + for _, param := range ssafn.Params { + if param.Object() == obj { + ssaobj = param + break + } + } + if ssaobj == nil { + continue + } + refs := ssaobj.Referrers() + if refs == nil { + continue + } + if len(lint.FilterDebug(*refs)) != 0 { + continue + } + + assigned := false + ast.Inspect(body, func(node ast.Node) bool { + assign, ok := node.(*ast.AssignStmt) + if !ok { + return true + } + for _, lhs := range assign.Lhs { + ident, ok := lhs.(*ast.Ident) + if !ok { + continue + } + if j.Program.Info.ObjectOf(ident) == obj { + assigned = true + return false + } + } + return true + }) + if assigned { + j.Errorf(arg, "argument %s is overwritten before first use", arg) + } + } + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckIneffectiveLoop(j *lint.Job) { + // This check detects some, but not all unconditional loop exits. + // We give up in the following cases: + // + // - a goto anywhere in the loop. The goto might skip over our + // return, and we don't check that it doesn't. + // + // - any nested, unlabelled continue, even if it is in another + // loop or closure. + fn := func(node ast.Node) bool { + var body *ast.BlockStmt + switch fn := node.(type) { + case *ast.FuncDecl: + body = fn.Body + case *ast.FuncLit: + body = fn.Body + default: + return true + } + if body == nil { + return true + } + labels := map[*ast.Object]ast.Stmt{} + ast.Inspect(body, func(node ast.Node) bool { + label, ok := node.(*ast.LabeledStmt) + if !ok { + return true + } + labels[label.Label.Obj] = label.Stmt + return true + }) + + ast.Inspect(body, func(node ast.Node) bool { + var loop ast.Node + var body *ast.BlockStmt + switch node := node.(type) { + case *ast.ForStmt: + body = node.Body + loop = node + case *ast.RangeStmt: + typ := j.Program.Info.TypeOf(node.X) + if _, ok := typ.Underlying().(*types.Map); ok { + // looping once over a map is a valid pattern for + // getting an arbitrary element. + return true + } + body = node.Body + loop = node + default: + return true + } + if len(body.List) < 2 { + // avoid flagging the somewhat common pattern of using + // a range loop to get the first element in a slice, + // or the first rune in a string. + return true + } + var unconditionalExit ast.Node + hasBranching := false + for _, stmt := range body.List { + switch stmt := stmt.(type) { + case *ast.BranchStmt: + switch stmt.Tok { + case token.BREAK: + if stmt.Label == nil || labels[stmt.Label.Obj] == loop { + unconditionalExit = stmt + } + case token.CONTINUE: + if stmt.Label == nil || labels[stmt.Label.Obj] == loop { + unconditionalExit = nil + return false + } + } + case *ast.ReturnStmt: + unconditionalExit = stmt + case *ast.IfStmt, *ast.ForStmt, *ast.RangeStmt, *ast.SwitchStmt, *ast.SelectStmt: + hasBranching = true + } + } + if unconditionalExit == nil || !hasBranching { + return false + } + ast.Inspect(body, func(node ast.Node) bool { + if branch, ok := node.(*ast.BranchStmt); ok { + + switch branch.Tok { + case token.GOTO: + unconditionalExit = nil + return false + case token.CONTINUE: + if branch.Label != nil && labels[branch.Label.Obj] != loop { + return true + } + unconditionalExit = nil + return false + } + } + return true + }) + if unconditionalExit != nil { + j.Errorf(unconditionalExit, "the surrounding loop is unconditionally terminated") + } + return true + }) + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckNilContext(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + if len(call.Args) == 0 { + return true + } + if typ, ok := j.Program.Info.TypeOf(call.Args[0]).(*types.Basic); !ok || typ.Kind() != types.UntypedNil { + return true + } + sig, ok := j.Program.Info.TypeOf(call.Fun).(*types.Signature) + if !ok { + return true + } + if sig.Params().Len() == 0 { + return true + } + if types.TypeString(sig.Params().At(0).Type(), nil) != "context.Context" { + return true + } + j.Errorf(call.Args[0], + "do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use") + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckSeeker(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + sel, ok := call.Fun.(*ast.SelectorExpr) + if !ok { + return true + } + if sel.Sel.Name != "Seek" { + return true + } + if len(call.Args) != 2 { + return true + } + arg0, ok := call.Args[0].(*ast.SelectorExpr) + if !ok { + return true + } + switch arg0.Sel.Name { + case "SeekStart", "SeekCurrent", "SeekEnd": + default: + return true + } + pkg, ok := arg0.X.(*ast.Ident) + if !ok { + return true + } + if pkg.Name != "io" { + return true + } + j.Errorf(call, "the first argument of io.Seeker is the offset, but an io.Seek* constant is being used instead") + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckIneffectiveAppend(j *lint.Job) { + isAppend := func(ins ssa.Value) bool { + call, ok := ins.(*ssa.Call) + if !ok { + return false + } + if call.Call.IsInvoke() { + return false + } + if builtin, ok := call.Call.Value.(*ssa.Builtin); !ok || builtin.Name() != "append" { + return false + } + return true + } + + for _, ssafn := range j.Program.InitialFunctions { + for _, block := range ssafn.Blocks { + for _, ins := range block.Instrs { + val, ok := ins.(ssa.Value) + if !ok || !isAppend(val) { + continue + } + + isUsed := false + visited := map[ssa.Instruction]bool{} + var walkRefs func(refs []ssa.Instruction) + walkRefs = func(refs []ssa.Instruction) { + loop: + for _, ref := range refs { + if visited[ref] { + continue + } + visited[ref] = true + if _, ok := ref.(*ssa.DebugRef); ok { + continue + } + switch ref := ref.(type) { + case *ssa.Phi: + walkRefs(*ref.Referrers()) + case *ssa.Sigma: + walkRefs(*ref.Referrers()) + case ssa.Value: + if !isAppend(ref) { + isUsed = true + } else { + walkRefs(*ref.Referrers()) + } + case ssa.Instruction: + isUsed = true + break loop + } + } + } + refs := val.Referrers() + if refs == nil { + continue + } + walkRefs(*refs) + if !isUsed { + j.Errorf(ins, "this result of append is never used, except maybe in other appends") + } + } + } + } +} + +func (c *Checker) CheckConcurrentTesting(j *lint.Job) { + for _, ssafn := range j.Program.InitialFunctions { + for _, block := range ssafn.Blocks { + for _, ins := range block.Instrs { + gostmt, ok := ins.(*ssa.Go) + if !ok { + continue + } + var fn *ssa.Function + switch val := gostmt.Call.Value.(type) { + case *ssa.Function: + fn = val + case *ssa.MakeClosure: + fn = val.Fn.(*ssa.Function) + default: + continue + } + if fn.Blocks == nil { + continue + } + for _, block := range fn.Blocks { + for _, ins := range block.Instrs { + call, ok := ins.(*ssa.Call) + if !ok { + continue + } + if call.Call.IsInvoke() { + continue + } + callee := call.Call.StaticCallee() + if callee == nil { + continue + } + recv := callee.Signature.Recv() + if recv == nil { + continue + } + if types.TypeString(recv.Type(), nil) != "*testing.common" { + continue + } + fn, ok := call.Call.StaticCallee().Object().(*types.Func) + if !ok { + continue + } + name := fn.Name() + switch name { + case "FailNow", "Fatal", "Fatalf", "SkipNow", "Skip", "Skipf": + default: + continue + } + j.Errorf(gostmt, "the goroutine calls T.%s, which must be called in the same goroutine as the test", name) + } + } + } + } + } +} + +func (c *Checker) CheckCyclicFinalizer(j *lint.Job) { + for _, ssafn := range j.Program.InitialFunctions { + node := c.funcDescs.CallGraph.CreateNode(ssafn) + for _, edge := range node.Out { + if edge.Callee.Func.RelString(nil) != "runtime.SetFinalizer" { + continue + } + arg0 := edge.Site.Common().Args[0] + if iface, ok := arg0.(*ssa.MakeInterface); ok { + arg0 = iface.X + } + unop, ok := arg0.(*ssa.UnOp) + if !ok { + continue + } + v, ok := unop.X.(*ssa.Alloc) + if !ok { + continue + } + arg1 := edge.Site.Common().Args[1] + if iface, ok := arg1.(*ssa.MakeInterface); ok { + arg1 = iface.X + } + mc, ok := arg1.(*ssa.MakeClosure) + if !ok { + continue + } + for _, b := range mc.Bindings { + if b == v { + pos := j.Program.DisplayPosition(mc.Fn.Pos()) + j.Errorf(edge.Site, "the finalizer closes over the object, preventing the finalizer from ever running (at %s)", pos) + } + } + } + } +} + +func (c *Checker) CheckSliceOutOfBounds(j *lint.Job) { + for _, ssafn := range j.Program.InitialFunctions { + for _, block := range ssafn.Blocks { + for _, ins := range block.Instrs { + ia, ok := ins.(*ssa.IndexAddr) + if !ok { + continue + } + if _, ok := ia.X.Type().Underlying().(*types.Slice); !ok { + continue + } + sr, ok1 := c.funcDescs.Get(ssafn).Ranges[ia.X].(vrp.SliceInterval) + idxr, ok2 := c.funcDescs.Get(ssafn).Ranges[ia.Index].(vrp.IntInterval) + if !ok1 || !ok2 || !sr.IsKnown() || !idxr.IsKnown() || sr.Length.Empty() || idxr.Empty() { + continue + } + if idxr.Lower.Cmp(sr.Length.Upper) >= 0 { + j.Errorf(ia, "index out of bounds") + } + } + } + } +} + +func (c *Checker) CheckDeferLock(j *lint.Job) { + for _, ssafn := range j.Program.InitialFunctions { + for _, block := range ssafn.Blocks { + instrs := lint.FilterDebug(block.Instrs) + if len(instrs) < 2 { + continue + } + for i, ins := range instrs[:len(instrs)-1] { + call, ok := ins.(*ssa.Call) + if !ok { + continue + } + if !lint.IsCallTo(call.Common(), "(*sync.Mutex).Lock") && !lint.IsCallTo(call.Common(), "(*sync.RWMutex).RLock") { + continue + } + nins, ok := instrs[i+1].(*ssa.Defer) + if !ok { + continue + } + if !lint.IsCallTo(&nins.Call, "(*sync.Mutex).Lock") && !lint.IsCallTo(&nins.Call, "(*sync.RWMutex).RLock") { + continue + } + if call.Common().Args[0] != nins.Call.Args[0] { + continue + } + name := shortCallName(call.Common()) + alt := "" + switch name { + case "Lock": + alt = "Unlock" + case "RLock": + alt = "RUnlock" + } + j.Errorf(nins, "deferring %s right after having locked already; did you mean to defer %s?", name, alt) + } + } + } +} + +func (c *Checker) CheckNaNComparison(j *lint.Job) { + isNaN := func(v ssa.Value) bool { + call, ok := v.(*ssa.Call) + if !ok { + return false + } + return lint.IsCallTo(call.Common(), "math.NaN") + } + for _, ssafn := range j.Program.InitialFunctions { + for _, block := range ssafn.Blocks { + for _, ins := range block.Instrs { + ins, ok := ins.(*ssa.BinOp) + if !ok { + continue + } + if isNaN(ins.X) || isNaN(ins.Y) { + j.Errorf(ins, "no value is equal to NaN, not even NaN itself") + } + } + } + } +} + +func (c *Checker) CheckInfiniteRecursion(j *lint.Job) { + for _, ssafn := range j.Program.InitialFunctions { + node := c.funcDescs.CallGraph.CreateNode(ssafn) + for _, edge := range node.Out { + if edge.Callee != node { + continue + } + if _, ok := edge.Site.(*ssa.Go); ok { + // Recursively spawning goroutines doesn't consume + // stack space infinitely, so don't flag it. + continue + } + + block := edge.Site.Block() + canReturn := false + for _, b := range ssafn.Blocks { + if block.Dominates(b) { + continue + } + if len(b.Instrs) == 0 { + continue + } + if _, ok := b.Instrs[len(b.Instrs)-1].(*ssa.Return); ok { + canReturn = true + break + } + } + if canReturn { + continue + } + j.Errorf(edge.Site, "infinite recursive call") + } + } +} + +func objectName(obj types.Object) string { + if obj == nil { + return "<nil>" + } + var name string + if obj.Pkg() != nil && obj.Pkg().Scope().Lookup(obj.Name()) == obj { + var s string + s = obj.Pkg().Path() + if s != "" { + name += s + "." + } + } + name += obj.Name() + return name +} + +func isName(j *lint.Job, expr ast.Expr, name string) bool { + var obj types.Object + switch expr := expr.(type) { + case *ast.Ident: + obj = j.Program.Info.ObjectOf(expr) + case *ast.SelectorExpr: + obj = j.Program.Info.ObjectOf(expr.Sel) + } + return objectName(obj) == name +} + +func (c *Checker) CheckLeakyTimeTick(j *lint.Job) { + for _, ssafn := range j.Program.InitialFunctions { + if j.IsInMain(ssafn) || j.IsInTest(ssafn) { + continue + } + for _, block := range ssafn.Blocks { + for _, ins := range block.Instrs { + call, ok := ins.(*ssa.Call) + if !ok || !lint.IsCallTo(call.Common(), "time.Tick") { + continue + } + if c.funcDescs.Get(call.Parent()).Infinite { + continue + } + j.Errorf(call, "using time.Tick leaks the underlying ticker, consider using it only in endless functions, tests and the main package, and use time.NewTicker here") + } + } + } +} + +func (c *Checker) CheckDoubleNegation(j *lint.Job) { + fn := func(node ast.Node) bool { + unary1, ok := node.(*ast.UnaryExpr) + if !ok { + return true + } + unary2, ok := unary1.X.(*ast.UnaryExpr) + if !ok { + return true + } + if unary1.Op != token.NOT || unary2.Op != token.NOT { + return true + } + j.Errorf(unary1, "negating a boolean twice has no effect; is this a typo?") + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func hasSideEffects(node ast.Node) bool { + dynamic := false + ast.Inspect(node, func(node ast.Node) bool { + switch node := node.(type) { + case *ast.CallExpr: + dynamic = true + return false + case *ast.UnaryExpr: + if node.Op == token.ARROW { + dynamic = true + return false + } + } + return true + }) + return dynamic +} + +func (c *Checker) CheckRepeatedIfElse(j *lint.Job) { + seen := map[ast.Node]bool{} + + var collectConds func(ifstmt *ast.IfStmt, inits []ast.Stmt, conds []ast.Expr) ([]ast.Stmt, []ast.Expr) + collectConds = func(ifstmt *ast.IfStmt, inits []ast.Stmt, conds []ast.Expr) ([]ast.Stmt, []ast.Expr) { + seen[ifstmt] = true + if ifstmt.Init != nil { + inits = append(inits, ifstmt.Init) + } + conds = append(conds, ifstmt.Cond) + if elsestmt, ok := ifstmt.Else.(*ast.IfStmt); ok { + return collectConds(elsestmt, inits, conds) + } + return inits, conds + } + fn := func(node ast.Node) bool { + ifstmt, ok := node.(*ast.IfStmt) + if !ok { + return true + } + if seen[ifstmt] { + return true + } + inits, conds := collectConds(ifstmt, nil, nil) + if len(inits) > 0 { + return true + } + for _, cond := range conds { + if hasSideEffects(cond) { + return true + } + } + counts := map[string]int{} + for _, cond := range conds { + s := j.Render(cond) + counts[s]++ + if counts[s] == 2 { + j.Errorf(cond, "this condition occurs multiple times in this if/else if chain") + } + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckSillyBitwiseOps(j *lint.Job) { + for _, ssafn := range j.Program.InitialFunctions { + for _, block := range ssafn.Blocks { + for _, ins := range block.Instrs { + ins, ok := ins.(*ssa.BinOp) + if !ok { + continue + } + + if c, ok := ins.Y.(*ssa.Const); !ok || c.Value == nil || c.Value.Kind() != constant.Int || c.Uint64() != 0 { + continue + } + switch ins.Op { + case token.AND, token.OR, token.XOR: + default: + // we do not flag shifts because too often, x<<0 is part + // of a pattern, x<<0, x<<8, x<<16, ... + continue + } + path, _ := astutil.PathEnclosingInterval(j.File(ins), ins.Pos(), ins.Pos()) + if len(path) == 0 { + continue + } + if node, ok := path[0].(*ast.BinaryExpr); !ok || !lint.IsZero(node.Y) { + continue + } + + switch ins.Op { + case token.AND: + j.Errorf(ins, "x & 0 always equals 0") + case token.OR, token.XOR: + j.Errorf(ins, "x %s 0 always equals x", ins.Op) + } + } + } + } +} + +func (c *Checker) CheckNonOctalFileMode(j *lint.Job) { + fn := func(node ast.Node) bool { + call, ok := node.(*ast.CallExpr) + if !ok { + return true + } + sig, ok := j.Program.Info.TypeOf(call.Fun).(*types.Signature) + if !ok { + return true + } + n := sig.Params().Len() + var args []int + for i := 0; i < n; i++ { + typ := sig.Params().At(i).Type() + if types.TypeString(typ, nil) == "os.FileMode" { + args = append(args, i) + } + } + for _, i := range args { + lit, ok := call.Args[i].(*ast.BasicLit) + if !ok { + continue + } + if len(lit.Value) == 3 && + lit.Value[0] != '0' && + lit.Value[0] >= '0' && lit.Value[0] <= '7' && + lit.Value[1] >= '0' && lit.Value[1] <= '7' && + lit.Value[2] >= '0' && lit.Value[2] <= '7' { + + v, err := strconv.ParseInt(lit.Value, 10, 64) + if err != nil { + continue + } + j.Errorf(call.Args[i], "file mode '%s' evaluates to %#o; did you mean '0%s'?", lit.Value, v, lit.Value) + } + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckPureFunctions(j *lint.Job) { +fnLoop: + for _, ssafn := range j.Program.InitialFunctions { + if j.IsInTest(ssafn) { + params := ssafn.Signature.Params() + for i := 0; i < params.Len(); i++ { + param := params.At(i) + if types.TypeString(param.Type(), nil) == "*testing.B" { + // Ignore discarded pure functions in code related + // to benchmarks. Instead of matching BenchmarkFoo + // functions, we match any function accepting a + // *testing.B. Benchmarks sometimes call generic + // functions for doing the actual work, and + // checking for the parameter is a lot easier and + // faster than analyzing call trees. + continue fnLoop + } + } + } + + for _, b := range ssafn.Blocks { + for _, ins := range b.Instrs { + ins, ok := ins.(*ssa.Call) + if !ok { + continue + } + refs := ins.Referrers() + if refs == nil || len(lint.FilterDebug(*refs)) > 0 { + continue + } + callee := ins.Common().StaticCallee() + if callee == nil { + continue + } + if c.funcDescs.Get(callee).Pure && !c.funcDescs.Get(callee).Stub { + j.Errorf(ins, "%s is a pure function but its return value is ignored", callee.Name()) + continue + } + } + } + } +} + +func (c *Checker) isDeprecated(j *lint.Job, ident *ast.Ident) (bool, string) { + obj := j.Program.Info.ObjectOf(ident) + if obj.Pkg() == nil { + return false, "" + } + alt := c.deprecatedObjs[obj] + return alt != "", alt +} + +func selectorName(j *lint.Job, expr *ast.SelectorExpr) string { + sel := j.Program.Info.Selections[expr] + if sel == nil { + if x, ok := expr.X.(*ast.Ident); ok { + pkg, ok := j.Program.Info.ObjectOf(x).(*types.PkgName) + if !ok { + // This shouldn't happen + return fmt.Sprintf("%s.%s", x.Name, expr.Sel.Name) + } + return fmt.Sprintf("%s.%s", pkg.Imported().Path(), expr.Sel.Name) + } + panic(fmt.Sprintf("unsupported selector: %v", expr)) + } + return fmt.Sprintf("(%s).%s", sel.Recv(), sel.Obj().Name()) +} + +func (c *Checker) enclosingFunc(sel *ast.SelectorExpr) *ssa.Function { + fn := c.nodeFns[sel] + if fn == nil { + return nil + } + for fn.Parent() != nil { + fn = fn.Parent() + } + return fn +} + +func (c *Checker) CheckDeprecated(j *lint.Job) { + fn := func(node ast.Node) bool { + sel, ok := node.(*ast.SelectorExpr) + if !ok { + return true + } + + obj := j.Program.Info.ObjectOf(sel.Sel) + if obj.Pkg() == nil { + return true + } + nodePkg := j.NodePackage(node).Pkg + if nodePkg == obj.Pkg() || obj.Pkg().Path()+"_test" == nodePkg.Path() { + // Don't flag stuff in our own package + return true + } + if ok, alt := c.isDeprecated(j, sel.Sel); ok { + // Look for the first available alternative, not the first + // version something was deprecated in. If a function was + // deprecated in Go 1.6, an alternative has been available + // already in 1.0, and we're targetting 1.2, it still + // makes sense to use the alternative from 1.0, to be + // future-proof. + minVersion := deprecated.Stdlib[selectorName(j, sel)].AlternativeAvailableSince + if !j.IsGoVersion(minVersion) { + return true + } + + if fn := c.enclosingFunc(sel); fn != nil { + if _, ok := c.deprecatedObjs[fn.Object()]; ok { + // functions that are deprecated may use deprecated + // symbols + return true + } + } + j.Errorf(sel, "%s is deprecated: %s", j.Render(sel), alt) + return true + } + return true + } + for _, f := range j.Program.Files { + ast.Inspect(f, fn) + } +} + +func (c *Checker) callChecker(rules map[string]CallCheck) func(j *lint.Job) { + return func(j *lint.Job) { + c.checkCalls(j, rules) + } +} + +func (c *Checker) checkCalls(j *lint.Job, rules map[string]CallCheck) { + for _, ssafn := range j.Program.InitialFunctions { + node := c.funcDescs.CallGraph.CreateNode(ssafn) + for _, edge := range node.Out { + callee := edge.Callee.Func + obj, ok := callee.Object().(*types.Func) + if !ok { + continue + } + + r, ok := rules[obj.FullName()] + if !ok { + continue + } + var args []*Argument + ssaargs := edge.Site.Common().Args + if callee.Signature.Recv() != nil { + ssaargs = ssaargs[1:] + } + for _, arg := range ssaargs { + if iarg, ok := arg.(*ssa.MakeInterface); ok { + arg = iarg.X + } + vr := c.funcDescs.Get(edge.Site.Parent()).Ranges[arg] + args = append(args, &Argument{Value: Value{arg, vr}}) + } + call := &Call{ + Job: j, + Instr: edge.Site, + Args: args, + Checker: c, + Parent: edge.Site.Parent(), + } + r(call) + for idx, arg := range call.Args { + _ = idx + for _, e := range arg.invalids { + // path, _ := astutil.PathEnclosingInterval(f.File, edge.Site.Pos(), edge.Site.Pos()) + // if len(path) < 2 { + // continue + // } + // astcall, ok := path[0].(*ast.CallExpr) + // if !ok { + // continue + // } + // j.Errorf(astcall.Args[idx], "%s", e) + + j.Errorf(edge.Site, "%s", e) + } + } + for _, e := range call.invalids { + j.Errorf(call.Instr.Common(), "%s", e) + } + } + } +} + +func unwrapFunction(val ssa.Value) *ssa.Function { + switch val := val.(type) { + case *ssa.Function: + return val + case *ssa.MakeClosure: + return val.Fn.(*ssa.Function) + default: + return nil + } +} + +func shortCallName(call *ssa.CallCommon) string { + if call.IsInvoke() { + return "" + } + switch v := call.Value.(type) { + case *ssa.Function: + fn, ok := v.Object().(*types.Func) + if !ok { + return "" + } + return fn.Name() + case *ssa.Builtin: + return v.Name() + } + return "" +} + +func hasCallTo(block *ssa.BasicBlock, name string) bool { + for _, ins := range block.Instrs { + call, ok := ins.(*ssa.Call) + if !ok { + continue + } + if lint.IsCallTo(call.Common(), name) { + return true + } + } + return false +} + +// deref returns a pointer's element type; otherwise it returns typ. +func deref(typ types.Type) types.Type { + if p, ok := typ.Underlying().(*types.Pointer); ok { + return p.Elem() + } + return typ +} + +func (c *Checker) CheckWriterBufferModified(j *lint.Job) { + // TODO(dh): this might be a good candidate for taint analysis. + // Taint the argument as MUST_NOT_MODIFY, then propagate that + // through functions like bytes.Split + + for _, ssafn := range j.Program.InitialFunctions { + sig := ssafn.Signature + if ssafn.Name() != "Write" || sig.Recv() == nil || sig.Params().Len() != 1 || sig.Results().Len() != 2 { + continue + } + tArg, ok := sig.Params().At(0).Type().(*types.Slice) + if !ok { + continue + } + if basic, ok := tArg.Elem().(*types.Basic); !ok || basic.Kind() != types.Byte { + continue + } + if basic, ok := sig.Results().At(0).Type().(*types.Basic); !ok || basic.Kind() != types.Int { + continue + } + if named, ok := sig.Results().At(1).Type().(*types.Named); !ok || types.TypeString(named, nil) != "error" { + continue + } + + for _, block := range ssafn.Blocks { + for _, ins := range block.Instrs { + switch ins := ins.(type) { + case *ssa.Store: + addr, ok := ins.Addr.(*ssa.IndexAddr) + if !ok { + continue + } + if addr.X != ssafn.Params[1] { + continue + } + j.Errorf(ins, "io.Writer.Write must not modify the provided buffer, not even temporarily") + case *ssa.Call: + if !lint.IsCallTo(ins.Common(), "append") { + continue + } + if ins.Common().Args[0] != ssafn.Params[1] { + continue + } + j.Errorf(ins, "io.Writer.Write must not modify the provided buffer, not even temporarily") + } + } + } + } +} + +func loopedRegexp(name string) CallCheck { + return func(call *Call) { + if len(extractConsts(call.Args[0].Value.Value)) == 0 { + return + } + if !call.Checker.isInLoop(call.Instr.Block()) { + return + } + call.Invalid(fmt.Sprintf("calling %s in a loop has poor performance, consider using regexp.Compile", name)) + } +} + +func (c *Checker) CheckEmptyBranch(j *lint.Job) { + fn := func(node ast.Node) bool { + ifstmt, ok := node.(*ast.IfStmt) + if !ok { + return true + } + ssafn := c.nodeFns[node] + if lint.IsExample(ssafn) { + return true + } + if ifstmt.Else != nil { + b, ok := ifstmt.Else.(*ast.BlockStmt) + if !ok || len(b.List) != 0 { + return true + } + j.Errorf(ifstmt.Else, "empty branch") + } + if len(ifstmt.Body.List) != 0 { + return true + } + j.Errorf(ifstmt, "empty branch") + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func (c *Checker) CheckMapBytesKey(j *lint.Job) { + for _, fn := range j.Program.InitialFunctions { + for _, b := range fn.Blocks { + insLoop: + for _, ins := range b.Instrs { + // find []byte -> string conversions + conv, ok := ins.(*ssa.Convert) + if !ok || conv.Type() != types.Universe.Lookup("string").Type() { + continue + } + if s, ok := conv.X.Type().(*types.Slice); !ok || s.Elem() != types.Universe.Lookup("byte").Type() { + continue + } + refs := conv.Referrers() + // need at least two (DebugRef) references: the + // conversion and the *ast.Ident + if refs == nil || len(*refs) < 2 { + continue + } + ident := false + // skip first reference, that's the conversion itself + for _, ref := range (*refs)[1:] { + switch ref := ref.(type) { + case *ssa.DebugRef: + if _, ok := ref.Expr.(*ast.Ident); !ok { + // the string seems to be used somewhere + // unexpected; the default branch should + // catch this already, but be safe + continue insLoop + } else { + ident = true + } + case *ssa.Lookup: + default: + // the string is used somewhere else than a + // map lookup + continue insLoop + } + } + + // the result of the conversion wasn't assigned to an + // identifier + if !ident { + continue + } + j.Errorf(conv, "m[string(key)] would be more efficient than k := string(key); m[k]") + } + } + } +} + +func (c *Checker) CheckRangeStringRunes(j *lint.Job) { + sharedcheck.CheckRangeStringRunes(c.nodeFns, j) +} + +func (c *Checker) CheckSelfAssignment(j *lint.Job) { + fn := func(node ast.Node) bool { + assign, ok := node.(*ast.AssignStmt) + if !ok { + return true + } + if assign.Tok != token.ASSIGN || len(assign.Lhs) != len(assign.Rhs) { + return true + } + for i, stmt := range assign.Lhs { + rlh := j.Render(stmt) + rrh := j.Render(assign.Rhs[i]) + if rlh == rrh { + j.Errorf(assign, "self-assignment of %s to %s", rrh, rlh) + } + } + return true + } + for _, f := range c.filterGenerated(j.Program.Files) { + ast.Inspect(f, fn) + } +} + +func buildTagsIdentical(s1, s2 []string) bool { + if len(s1) != len(s2) { + return false + } + s1s := make([]string, len(s1)) + copy(s1s, s1) + sort.Strings(s1s) + s2s := make([]string, len(s2)) + copy(s2s, s2) + sort.Strings(s2s) + for i, s := range s1s { + if s != s2s[i] { + return false + } + } + return true +} + +func (c *Checker) CheckDuplicateBuildConstraints(job *lint.Job) { + for _, f := range c.filterGenerated(job.Program.Files) { + constraints := buildTags(f) + for i, constraint1 := range constraints { + for j, constraint2 := range constraints { + if i >= j { + continue + } + if buildTagsIdentical(constraint1, constraint2) { + job.Errorf(f, "identical build constraints %q and %q", + strings.Join(constraint1, " "), + strings.Join(constraint2, " ")) + } + } + } + } +} diff --git a/vendor/honnef.co/go/tools/staticcheck/rules.go b/vendor/honnef.co/go/tools/staticcheck/rules.go new file mode 100644 index 0000000..60cc00c --- /dev/null +++ b/vendor/honnef.co/go/tools/staticcheck/rules.go @@ -0,0 +1,321 @@ +package staticcheck + +import ( + "fmt" + "go/constant" + "go/types" + "net" + "net/url" + "regexp" + "sort" + "strconv" + "strings" + "time" + "unicode/utf8" + + "honnef.co/go/tools/lint" + "honnef.co/go/tools/ssa" + "honnef.co/go/tools/staticcheck/vrp" +) + +const ( + MsgInvalidHostPort = "invalid port or service name in host:port pair" + MsgInvalidUTF8 = "argument is not a valid UTF-8 encoded string" + MsgNonUniqueCutset = "cutset contains duplicate characters" +) + +type Call struct { + Job *lint.Job + Instr ssa.CallInstruction + Args []*Argument + + Checker *Checker + Parent *ssa.Function + + invalids []string +} + +func (c *Call) Invalid(msg string) { + c.invalids = append(c.invalids, msg) +} + +type Argument struct { + Value Value + invalids []string +} + +func (arg *Argument) Invalid(msg string) { + arg.invalids = append(arg.invalids, msg) +} + +type Value struct { + Value ssa.Value + Range vrp.Range +} + +type CallCheck func(call *Call) + +func extractConsts(v ssa.Value) []*ssa.Const { + switch v := v.(type) { + case *ssa.Const: + return []*ssa.Const{v} + case *ssa.MakeInterface: + return extractConsts(v.X) + default: + return nil + } +} + +func ValidateRegexp(v Value) error { + for _, c := range extractConsts(v.Value) { + if c.Value == nil { + continue + } + if c.Value.Kind() != constant.String { + continue + } + s := constant.StringVal(c.Value) + if _, err := regexp.Compile(s); err != nil { + return err + } + } + return nil +} + +func ValidateTimeLayout(v Value) error { + for _, c := range extractConsts(v.Value) { + if c.Value == nil { + continue + } + if c.Value.Kind() != constant.String { + continue + } + s := constant.StringVal(c.Value) + s = strings.Replace(s, "_", " ", -1) + s = strings.Replace(s, "Z", "-", -1) + _, err := time.Parse(s, s) + if err != nil { + return err + } + } + return nil +} + +func ValidateURL(v Value) error { + for _, c := range extractConsts(v.Value) { + if c.Value == nil { + continue + } + if c.Value.Kind() != constant.String { + continue + } + s := constant.StringVal(c.Value) + _, err := url.Parse(s) + if err != nil { + return fmt.Errorf("%q is not a valid URL: %s", s, err) + } + } + return nil +} + +func IntValue(v Value, z vrp.Z) bool { + r, ok := v.Range.(vrp.IntInterval) + if !ok || !r.IsKnown() { + return false + } + if r.Lower != r.Upper { + return false + } + if r.Lower.Cmp(z) == 0 { + return true + } + return false +} + +func InvalidUTF8(v Value) bool { + for _, c := range extractConsts(v.Value) { + if c.Value == nil { + continue + } + if c.Value.Kind() != constant.String { + continue + } + s := constant.StringVal(c.Value) + if !utf8.ValidString(s) { + return true + } + } + return false +} + +func UnbufferedChannel(v Value) bool { + r, ok := v.Range.(vrp.ChannelInterval) + if !ok || !r.IsKnown() { + return false + } + if r.Size.Lower.Cmp(vrp.NewZ(0)) == 0 && + r.Size.Upper.Cmp(vrp.NewZ(0)) == 0 { + return true + } + return false +} + +func Pointer(v Value) bool { + switch v.Value.Type().Underlying().(type) { + case *types.Pointer, *types.Interface: + return true + } + return false +} + +func ConvertedFromInt(v Value) bool { + conv, ok := v.Value.(*ssa.Convert) + if !ok { + return false + } + b, ok := conv.X.Type().Underlying().(*types.Basic) + if !ok { + return false + } + if (b.Info() & types.IsInteger) == 0 { + return false + } + return true +} + +func validEncodingBinaryType(j *lint.Job, typ types.Type) bool { + typ = typ.Underlying() + switch typ := typ.(type) { + case *types.Basic: + switch typ.Kind() { + case types.Uint8, types.Uint16, types.Uint32, types.Uint64, + types.Int8, types.Int16, types.Int32, types.Int64, + types.Float32, types.Float64, types.Complex64, types.Complex128, types.Invalid: + return true + case types.Bool: + return j.IsGoVersion(8) + } + return false + case *types.Struct: + n := typ.NumFields() + for i := 0; i < n; i++ { + if !validEncodingBinaryType(j, typ.Field(i).Type()) { + return false + } + } + return true + case *types.Array: + return validEncodingBinaryType(j, typ.Elem()) + case *types.Interface: + // we can't determine if it's a valid type or not + return true + } + return false +} + +func CanBinaryMarshal(j *lint.Job, v Value) bool { + typ := v.Value.Type().Underlying() + if ttyp, ok := typ.(*types.Pointer); ok { + typ = ttyp.Elem().Underlying() + } + if ttyp, ok := typ.(interface { + Elem() types.Type + }); ok { + if _, ok := ttyp.(*types.Pointer); !ok { + typ = ttyp.Elem() + } + } + + return validEncodingBinaryType(j, typ) +} + +func RepeatZeroTimes(name string, arg int) CallCheck { + return func(call *Call) { + arg := call.Args[arg] + if IntValue(arg.Value, vrp.NewZ(0)) { + arg.Invalid(fmt.Sprintf("calling %s with n == 0 will return no results, did you mean -1?", name)) + } + } +} + +func validateServiceName(s string) bool { + if len(s) < 1 || len(s) > 15 { + return false + } + if s[0] == '-' || s[len(s)-1] == '-' { + return false + } + if strings.Contains(s, "--") { + return false + } + hasLetter := false + for _, r := range s { + if (r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') { + hasLetter = true + continue + } + if r >= '0' && r <= '9' { + continue + } + return false + } + return hasLetter +} + +func validatePort(s string) bool { + n, err := strconv.ParseInt(s, 10, 64) + if err != nil { + return validateServiceName(s) + } + return n >= 0 && n <= 65535 +} + +func ValidHostPort(v Value) bool { + for _, k := range extractConsts(v.Value) { + if k.Value == nil { + continue + } + if k.Value.Kind() != constant.String { + continue + } + s := constant.StringVal(k.Value) + _, port, err := net.SplitHostPort(s) + if err != nil { + return false + } + // TODO(dh): check hostname + if !validatePort(port) { + return false + } + } + return true +} + +// ConvertedFrom reports whether value v was converted from type typ. +func ConvertedFrom(v Value, typ string) bool { + change, ok := v.Value.(*ssa.ChangeType) + return ok && types.TypeString(change.X.Type(), nil) == typ +} + +func UniqueStringCutset(v Value) bool { + for _, c := range extractConsts(v.Value) { + if c.Value == nil { + continue + } + if c.Value.Kind() != constant.String { + continue + } + s := constant.StringVal(c.Value) + rs := runeSlice(s) + if len(rs) < 2 { + continue + } + sort.Sort(rs) + for i, r := range rs[1:] { + if rs[i] == r { + return false + } + } + } + return true +} diff --git a/vendor/honnef.co/go/tools/staticcheck/vrp/channel.go b/vendor/honnef.co/go/tools/staticcheck/vrp/channel.go new file mode 100644 index 0000000..c8fbacb --- /dev/null +++ b/vendor/honnef.co/go/tools/staticcheck/vrp/channel.go @@ -0,0 +1,73 @@ +package vrp + +import ( + "fmt" + + "honnef.co/go/tools/ssa" +) + +type ChannelInterval struct { + Size IntInterval +} + +func (c ChannelInterval) Union(other Range) Range { + i, ok := other.(ChannelInterval) + if !ok { + i = ChannelInterval{EmptyIntInterval} + } + if c.Size.Empty() || !c.Size.IsKnown() { + return i + } + if i.Size.Empty() || !i.Size.IsKnown() { + return c + } + return ChannelInterval{ + Size: c.Size.Union(i.Size).(IntInterval), + } +} + +func (c ChannelInterval) String() string { + return c.Size.String() +} + +func (c ChannelInterval) IsKnown() bool { + return c.Size.IsKnown() +} + +type MakeChannelConstraint struct { + aConstraint + Buffer ssa.Value +} +type ChannelChangeTypeConstraint struct { + aConstraint + X ssa.Value +} + +func NewMakeChannelConstraint(buffer, y ssa.Value) Constraint { + return &MakeChannelConstraint{NewConstraint(y), buffer} +} +func NewChannelChangeTypeConstraint(x, y ssa.Value) Constraint { + return &ChannelChangeTypeConstraint{NewConstraint(y), x} +} + +func (c *MakeChannelConstraint) Operands() []ssa.Value { return []ssa.Value{c.Buffer} } +func (c *ChannelChangeTypeConstraint) Operands() []ssa.Value { return []ssa.Value{c.X} } + +func (c *MakeChannelConstraint) String() string { + return fmt.Sprintf("%s = make(chan, %s)", c.Y().Name, c.Buffer.Name()) +} +func (c *ChannelChangeTypeConstraint) String() string { + return fmt.Sprintf("%s = changetype(%s)", c.Y().Name, c.X.Name()) +} + +func (c *MakeChannelConstraint) Eval(g *Graph) Range { + i, ok := g.Range(c.Buffer).(IntInterval) + if !ok { + return ChannelInterval{NewIntInterval(NewZ(0), PInfinity)} + } + if i.Lower.Sign() == -1 { + i.Lower = NewZ(0) + } + return ChannelInterval{i} +} +func (c *ChannelChangeTypeConstraint) Eval(g *Graph) Range { return g.Range(c.X) } diff --git a/vendor/honnef.co/go/tools/staticcheck/vrp/int.go b/vendor/honnef.co/go/tools/staticcheck/vrp/int.go new file mode 100644 index 0000000..926bb7a --- /dev/null +++ b/vendor/honnef.co/go/tools/staticcheck/vrp/int.go @@ -0,0 +1,476 @@ +package vrp + +import ( + "fmt" + "go/token" + "go/types" + "math/big" + + "honnef.co/go/tools/ssa" +) + +type Zs []Z + +func (zs Zs) Len() int { + return len(zs) +} + +func (zs Zs) Less(i int, j int) bool { + return zs[i].Cmp(zs[j]) == -1 +} + +func (zs Zs) Swap(i int, j int) { + zs[i], zs[j] = zs[j], zs[i] +} + +type Z struct { + infinity int8 + integer *big.Int +} + +func NewZ(n int64) Z { + return NewBigZ(big.NewInt(n)) +} + +func NewBigZ(n *big.Int) Z { + return Z{integer: n} +} + +func (z1 Z) Infinite() bool { + return z1.infinity != 0 +} + +func (z1 Z) Add(z2 Z) Z { + if z2.Sign() == -1 { + return z1.Sub(z2.Negate()) + } + if z1 == NInfinity { + return NInfinity + } + if z1 == PInfinity { + return PInfinity + } + if z2 == PInfinity { + return PInfinity + } + + if !z1.Infinite() && !z2.Infinite() { + n := &big.Int{} + n.Add(z1.integer, z2.integer) + return NewBigZ(n) + } + + panic(fmt.Sprintf("%s + %s is not defined", z1, z2)) +} + +func (z1 Z) Sub(z2 Z) Z { + if z2.Sign() == -1 { + return z1.Add(z2.Negate()) + } + if !z1.Infinite() && !z2.Infinite() { + n := &big.Int{} + n.Sub(z1.integer, z2.integer) + return NewBigZ(n) + } + + if z1 != PInfinity && z2 == PInfinity { + return NInfinity + } + if z1.Infinite() && !z2.Infinite() { + return Z{infinity: z1.infinity} + } + if z1 == PInfinity && z2 == PInfinity { + return PInfinity + } + panic(fmt.Sprintf("%s - %s is not defined", z1, z2)) +} + +func (z1 Z) Mul(z2 Z) Z { + if (z1.integer != nil && z1.integer.Sign() == 0) || + (z2.integer != nil && z2.integer.Sign() == 0) { + return NewBigZ(&big.Int{}) + } + + if z1.infinity != 0 || z2.infinity != 0 { + return Z{infinity: int8(z1.Sign() * z2.Sign())} + } + + n := &big.Int{} + n.Mul(z1.integer, z2.integer) + return NewBigZ(n) +} + +func (z1 Z) Negate() Z { + if z1.infinity == 1 { + return NInfinity + } + if z1.infinity == -1 { + return PInfinity + } + n := &big.Int{} + n.Neg(z1.integer) + return NewBigZ(n) +} + +func (z1 Z) Sign() int { + if z1.infinity != 0 { + return int(z1.infinity) + } + return z1.integer.Sign() +} + +func (z1 Z) String() string { + if z1 == NInfinity { + return "-∞" + } + if z1 == PInfinity { + return "∞" + } + return fmt.Sprintf("%d", z1.integer) +} + +func (z1 Z) Cmp(z2 Z) int { + if z1.infinity == z2.infinity && z1.infinity != 0 { + return 0 + } + if z1 == PInfinity { + return 1 + } + if z1 == NInfinity { + return -1 + } + if z2 == NInfinity { + return 1 + } + if z2 == PInfinity { + return -1 + } + return z1.integer.Cmp(z2.integer) +} + +func MaxZ(zs ...Z) Z { + if len(zs) == 0 { + panic("Max called with no arguments") + } + if len(zs) == 1 { + return zs[0] + } + ret := zs[0] + for _, z := range zs[1:] { + if z.Cmp(ret) == 1 { + ret = z + } + } + return ret +} + +func MinZ(zs ...Z) Z { + if len(zs) == 0 { + panic("Min called with no arguments") + } + if len(zs) == 1 { + return zs[0] + } + ret := zs[0] + for _, z := range zs[1:] { + if z.Cmp(ret) == -1 { + ret = z + } + } + return ret +} + +var NInfinity = Z{infinity: -1} +var PInfinity = Z{infinity: 1} +var EmptyIntInterval = IntInterval{true, PInfinity, NInfinity} + +func InfinityFor(v ssa.Value) IntInterval { + if b, ok := v.Type().Underlying().(*types.Basic); ok { + if (b.Info() & types.IsUnsigned) != 0 { + return NewIntInterval(NewZ(0), PInfinity) + } + } + return NewIntInterval(NInfinity, PInfinity) +} + +type IntInterval struct { + known bool + Lower Z + Upper Z +} + +func NewIntInterval(l, u Z) IntInterval { + if u.Cmp(l) == -1 { + return EmptyIntInterval + } + return IntInterval{known: true, Lower: l, Upper: u} +} + +func (i IntInterval) IsKnown() bool { + return i.known +} + +func (i IntInterval) Empty() bool { + return i.Lower == PInfinity && i.Upper == NInfinity +} + +func (i IntInterval) IsMaxRange() bool { + return i.Lower == NInfinity && i.Upper == PInfinity +} + +func (i1 IntInterval) Intersection(i2 IntInterval) IntInterval { + if !i1.IsKnown() { + return i2 + } + if !i2.IsKnown() { + return i1 + } + if i1.Empty() || i2.Empty() { + return EmptyIntInterval + } + i3 := NewIntInterval(MaxZ(i1.Lower, i2.Lower), MinZ(i1.Upper, i2.Upper)) + if i3.Lower.Cmp(i3.Upper) == 1 { + return EmptyIntInterval + } + return i3 +} + +func (i1 IntInterval) Union(other Range) Range { + i2, ok := other.(IntInterval) + if !ok { + i2 = EmptyIntInterval + } + if i1.Empty() || !i1.IsKnown() { + return i2 + } + if i2.Empty() || !i2.IsKnown() { + return i1 + } + return NewIntInterval(MinZ(i1.Lower, i2.Lower), MaxZ(i1.Upper, i2.Upper)) +} + +func (i1 IntInterval) Add(i2 IntInterval) IntInterval { + if i1.Empty() || i2.Empty() { + return EmptyIntInterval + } + l1, u1, l2, u2 := i1.Lower, i1.Upper, i2.Lower, i2.Upper + return NewIntInterval(l1.Add(l2), u1.Add(u2)) +} + +func (i1 IntInterval) Sub(i2 IntInterval) IntInterval { + if i1.Empty() || i2.Empty() { + return EmptyIntInterval + } + l1, u1, l2, u2 := i1.Lower, i1.Upper, i2.Lower, i2.Upper + return NewIntInterval(l1.Sub(u2), u1.Sub(l2)) +} + +func (i1 IntInterval) Mul(i2 IntInterval) IntInterval { + if i1.Empty() || i2.Empty() { + return EmptyIntInterval + } + x1, x2 := i1.Lower, i1.Upper + y1, y2 := i2.Lower, i2.Upper + return NewIntInterval( + MinZ(x1.Mul(y1), x1.Mul(y2), x2.Mul(y1), x2.Mul(y2)), + MaxZ(x1.Mul(y1), x1.Mul(y2), x2.Mul(y1), x2.Mul(y2)), + ) +} + +func (i1 IntInterval) String() string { + if !i1.IsKnown() { + return "[⊥, ⊥]" + } + if i1.Empty() { + return "{}" + } + return fmt.Sprintf("[%s, %s]", i1.Lower, i1.Upper) +} + +type IntArithmeticConstraint struct { + aConstraint + A ssa.Value + B ssa.Value + Op token.Token + Fn func(IntInterval, IntInterval) IntInterval +} + +type IntAddConstraint struct{ *IntArithmeticConstraint } +type IntSubConstraint struct{ *IntArithmeticConstraint } +type IntMulConstraint struct{ *IntArithmeticConstraint } + +type IntConversionConstraint struct { + aConstraint + X ssa.Value +} + +type IntIntersectionConstraint struct { + aConstraint + ranges Ranges + A ssa.Value + B ssa.Value + Op token.Token + I IntInterval + resolved bool +} + +type IntIntervalConstraint struct { + aConstraint + I IntInterval +} + +func NewIntArithmeticConstraint(a, b, y ssa.Value, op token.Token, fn func(IntInterval, IntInterval) IntInterval) *IntArithmeticConstraint { + return &IntArithmeticConstraint{NewConstraint(y), a, b, op, fn} +} +func NewIntAddConstraint(a, b, y ssa.Value) Constraint { + return &IntAddConstraint{NewIntArithmeticConstraint(a, b, y, token.ADD, IntInterval.Add)} +} +func NewIntSubConstraint(a, b, y ssa.Value) Constraint { + return &IntSubConstraint{NewIntArithmeticConstraint(a, b, y, token.SUB, IntInterval.Sub)} +} +func NewIntMulConstraint(a, b, y ssa.Value) Constraint { + return &IntMulConstraint{NewIntArithmeticConstraint(a, b, y, token.MUL, IntInterval.Mul)} +} +func NewIntConversionConstraint(x, y ssa.Value) Constraint { + return &IntConversionConstraint{NewConstraint(y), x} +} +func NewIntIntersectionConstraint(a, b ssa.Value, op token.Token, ranges Ranges, y ssa.Value) Constraint { + return &IntIntersectionConstraint{ + aConstraint: NewConstraint(y), + ranges: ranges, + A: a, + B: b, + Op: op, + } +} +func NewIntIntervalConstraint(i IntInterval, y ssa.Value) Constraint { + return &IntIntervalConstraint{NewConstraint(y), i} +} + +func (c *IntArithmeticConstraint) Operands() []ssa.Value { return []ssa.Value{c.A, c.B} } +func (c *IntConversionConstraint) Operands() []ssa.Value { return []ssa.Value{c.X} } +func (c *IntIntersectionConstraint) Operands() []ssa.Value { return []ssa.Value{c.A} } +func (s *IntIntervalConstraint) Operands() []ssa.Value { return nil } + +func (c *IntArithmeticConstraint) String() string { + return fmt.Sprintf("%s = %s %s %s", c.Y().Name(), c.A.Name(), c.Op, c.B.Name()) +} +func (c *IntConversionConstraint) String() string { + return fmt.Sprintf("%s = %s(%s)", c.Y().Name(), c.Y().Type(), c.X.Name()) +} +func (c *IntIntersectionConstraint) String() string { + return fmt.Sprintf("%s = %s %s %s (%t branch)", c.Y().Name(), c.A.Name(), c.Op, c.B.Name(), c.Y().(*ssa.Sigma).Branch) +} +func (c *IntIntervalConstraint) String() string { return fmt.Sprintf("%s = %s", c.Y().Name(), c.I) } + +func (c *IntArithmeticConstraint) Eval(g *Graph) Range { + i1, i2 := g.Range(c.A).(IntInterval), g.Range(c.B).(IntInterval) + if !i1.IsKnown() || !i2.IsKnown() { + return IntInterval{} + } + return c.Fn(i1, i2) +} +func (c *IntConversionConstraint) Eval(g *Graph) Range { + s := &types.StdSizes{ + // XXX is it okay to assume the largest word size, or do we + // need to be platform specific? + WordSize: 8, + MaxAlign: 1, + } + fromI := g.Range(c.X).(IntInterval) + toI := g.Range(c.Y()).(IntInterval) + fromT := c.X.Type().Underlying().(*types.Basic) + toT := c.Y().Type().Underlying().(*types.Basic) + fromB := s.Sizeof(c.X.Type()) + toB := s.Sizeof(c.Y().Type()) + + if !fromI.IsKnown() { + return toI + } + if !toI.IsKnown() { + return fromI + } + + // uint<N> -> sint/uint<M>, M > N: [max(0, l1), min(2**N-1, u2)] + if (fromT.Info()&types.IsUnsigned != 0) && + toB > fromB { + + n := big.NewInt(1) + n.Lsh(n, uint(fromB*8)) + n.Sub(n, big.NewInt(1)) + return NewIntInterval( + MaxZ(NewZ(0), fromI.Lower), + MinZ(NewBigZ(n), toI.Upper), + ) + } + + // sint<N> -> sint<M>, M > N; [max(-∞, l1), min(2**N-1, u2)] + if (fromT.Info()&types.IsUnsigned == 0) && + (toT.Info()&types.IsUnsigned == 0) && + toB > fromB { + + n := big.NewInt(1) + n.Lsh(n, uint(fromB*8)) + n.Sub(n, big.NewInt(1)) + return NewIntInterval( + MaxZ(NInfinity, fromI.Lower), + MinZ(NewBigZ(n), toI.Upper), + ) + } + + return fromI +} +func (c *IntIntersectionConstraint) Eval(g *Graph) Range { + xi := g.Range(c.A).(IntInterval) + if !xi.IsKnown() { + return c.I + } + return xi.Intersection(c.I) +} +func (c *IntIntervalConstraint) Eval(*Graph) Range { return c.I } + +func (c *IntIntersectionConstraint) Futures() []ssa.Value { + return []ssa.Value{c.B} +} + +func (c *IntIntersectionConstraint) Resolve() { + r, ok := c.ranges[c.B].(IntInterval) + if !ok { + c.I = InfinityFor(c.Y()) + return + } + + switch c.Op { + case token.EQL: + c.I = r + case token.GTR: + c.I = NewIntInterval(r.Lower.Add(NewZ(1)), PInfinity) + case token.GEQ: + c.I = NewIntInterval(r.Lower, PInfinity) + case token.LSS: + // TODO(dh): do we need 0 instead of NInfinity for uints? + c.I = NewIntInterval(NInfinity, r.Upper.Sub(NewZ(1))) + case token.LEQ: + c.I = NewIntInterval(NInfinity, r.Upper) + case token.NEQ: + c.I = InfinityFor(c.Y()) + default: + panic("unsupported op " + c.Op.String()) + } +} + +func (c *IntIntersectionConstraint) IsKnown() bool { + return c.I.IsKnown() +} + +func (c *IntIntersectionConstraint) MarkUnresolved() { + c.resolved = false +} + +func (c *IntIntersectionConstraint) MarkResolved() { + c.resolved = true +} + +func (c *IntIntersectionConstraint) IsResolved() bool { + return c.resolved +} diff --git a/vendor/honnef.co/go/tools/staticcheck/vrp/slice.go b/vendor/honnef.co/go/tools/staticcheck/vrp/slice.go new file mode 100644 index 0000000..40658dd --- /dev/null +++ b/vendor/honnef.co/go/tools/staticcheck/vrp/slice.go @@ -0,0 +1,273 @@ +package vrp + +// TODO(dh): most of the constraints have implementations identical to +// that of strings. Consider reusing them. + +import ( + "fmt" + "go/types" + + "honnef.co/go/tools/ssa" +) + +type SliceInterval struct { + Length IntInterval +} + +func (s SliceInterval) Union(other Range) Range { + i, ok := other.(SliceInterval) + if !ok { + i = SliceInterval{EmptyIntInterval} + } + if s.Length.Empty() || !s.Length.IsKnown() { + return i + } + if i.Length.Empty() || !i.Length.IsKnown() { + return s + } + return SliceInterval{ + Length: s.Length.Union(i.Length).(IntInterval), + } +} +func (s SliceInterval) String() string { return s.Length.String() } +func (s SliceInterval) IsKnown() bool { return s.Length.IsKnown() } + +type SliceAppendConstraint struct { + aConstraint + A ssa.Value + B ssa.Value +} + +type SliceSliceConstraint struct { + aConstraint + X ssa.Value + Lower ssa.Value + Upper ssa.Value +} + +type ArraySliceConstraint struct { + aConstraint + X ssa.Value + Lower ssa.Value + Upper ssa.Value +} + +type SliceIntersectionConstraint struct { + aConstraint + X ssa.Value + I IntInterval +} + +type SliceLengthConstraint struct { + aConstraint + X ssa.Value +} + +type MakeSliceConstraint struct { + aConstraint + Size ssa.Value +} + +type SliceIntervalConstraint struct { + aConstraint + I IntInterval +} + +func NewSliceAppendConstraint(a, b, y ssa.Value) Constraint { + return &SliceAppendConstraint{NewConstraint(y), a, b} +} +func NewSliceSliceConstraint(x, lower, upper, y ssa.Value) Constraint { + return &SliceSliceConstraint{NewConstraint(y), x, lower, upper} +} +func NewArraySliceConstraint(x, lower, upper, y ssa.Value) Constraint { + return &ArraySliceConstraint{NewConstraint(y), x, lower, upper} +} +func NewSliceIntersectionConstraint(x ssa.Value, i IntInterval, y ssa.Value) Constraint { + return &SliceIntersectionConstraint{NewConstraint(y), x, i} +} +func NewSliceLengthConstraint(x, y ssa.Value) Constraint { + return &SliceLengthConstraint{NewConstraint(y), x} +} +func NewMakeSliceConstraint(size, y ssa.Value) Constraint { + return &MakeSliceConstraint{NewConstraint(y), size} +} +func NewSliceIntervalConstraint(i IntInterval, y ssa.Value) Constraint { + return &SliceIntervalConstraint{NewConstraint(y), i} +} + +func (c *SliceAppendConstraint) Operands() []ssa.Value { return []ssa.Value{c.A, c.B} } +func (c *SliceSliceConstraint) Operands() []ssa.Value { + ops := []ssa.Value{c.X} + if c.Lower != nil { + ops = append(ops, c.Lower) + } + if c.Upper != nil { + ops = append(ops, c.Upper) + } + return ops +} +func (c *ArraySliceConstraint) Operands() []ssa.Value { + ops := []ssa.Value{c.X} + if c.Lower != nil { + ops = append(ops, c.Lower) + } + if c.Upper != nil { + ops = append(ops, c.Upper) + } + return ops +} +func (c *SliceIntersectionConstraint) Operands() []ssa.Value { return []ssa.Value{c.X} } +func (c *SliceLengthConstraint) Operands() []ssa.Value { return []ssa.Value{c.X} } +func (c *MakeSliceConstraint) Operands() []ssa.Value { return []ssa.Value{c.Size} } +func (s *SliceIntervalConstraint) Operands() []ssa.Value { return nil } + +func (c *SliceAppendConstraint) String() string { + return fmt.Sprintf("%s = append(%s, %s)", c.Y().Name(), c.A.Name(), c.B.Name()) +} +func (c *SliceSliceConstraint) String() string { + var lname, uname string + if c.Lower != nil { + lname = c.Lower.Name() + } + if c.Upper != nil { + uname = c.Upper.Name() + } + return fmt.Sprintf("%s[%s:%s]", c.X.Name(), lname, uname) +} +func (c *ArraySliceConstraint) String() string { + var lname, uname string + if c.Lower != nil { + lname = c.Lower.Name() + } + if c.Upper != nil { + uname = c.Upper.Name() + } + return fmt.Sprintf("%s[%s:%s]", c.X.Name(), lname, uname) +} +func (c *SliceIntersectionConstraint) String() string { + return fmt.Sprintf("%s = %s.%t ⊓ %s", c.Y().Name(), c.X.Name(), c.Y().(*ssa.Sigma).Branch, c.I) +} +func (c *SliceLengthConstraint) String() string { + return fmt.Sprintf("%s = len(%s)", c.Y().Name(), c.X.Name()) +} +func (c *MakeSliceConstraint) String() string { + return fmt.Sprintf("%s = make(slice, %s)", c.Y().Name(), c.Size.Name()) +} +func (c *SliceIntervalConstraint) String() string { return fmt.Sprintf("%s = %s", c.Y().Name(), c.I) } + +func (c *SliceAppendConstraint) Eval(g *Graph) Range { + l1 := g.Range(c.A).(SliceInterval).Length + var l2 IntInterval + switch r := g.Range(c.B).(type) { + case SliceInterval: + l2 = r.Length + case StringInterval: + l2 = r.Length + default: + return SliceInterval{} + } + if !l1.IsKnown() || !l2.IsKnown() { + return SliceInterval{} + } + return SliceInterval{ + Length: l1.Add(l2), + } +} +func (c *SliceSliceConstraint) Eval(g *Graph) Range { + lr := NewIntInterval(NewZ(0), NewZ(0)) + if c.Lower != nil { + lr = g.Range(c.Lower).(IntInterval) + } + ur := g.Range(c.X).(SliceInterval).Length + if c.Upper != nil { + ur = g.Range(c.Upper).(IntInterval) + } + if !lr.IsKnown() || !ur.IsKnown() { + return SliceInterval{} + } + + ls := []Z{ + ur.Lower.Sub(lr.Lower), + ur.Upper.Sub(lr.Lower), + ur.Lower.Sub(lr.Upper), + ur.Upper.Sub(lr.Upper), + } + // TODO(dh): if we don't truncate lengths to 0 we might be able to + // easily detect slices with high < low. we'd need to treat -∞ + // specially, though. + for i, l := range ls { + if l.Sign() == -1 { + ls[i] = NewZ(0) + } + } + + return SliceInterval{ + Length: NewIntInterval(MinZ(ls...), MaxZ(ls...)), + } +} +func (c *ArraySliceConstraint) Eval(g *Graph) Range { + lr := NewIntInterval(NewZ(0), NewZ(0)) + if c.Lower != nil { + lr = g.Range(c.Lower).(IntInterval) + } + var l int64 + switch typ := c.X.Type().(type) { + case *types.Array: + l = typ.Len() + case *types.Pointer: + l = typ.Elem().(*types.Array).Len() + } + ur := NewIntInterval(NewZ(l), NewZ(l)) + if c.Upper != nil { + ur = g.Range(c.Upper).(IntInterval) + } + if !lr.IsKnown() || !ur.IsKnown() { + return SliceInterval{} + } + + ls := []Z{ + ur.Lower.Sub(lr.Lower), + ur.Upper.Sub(lr.Lower), + ur.Lower.Sub(lr.Upper), + ur.Upper.Sub(lr.Upper), + } + // TODO(dh): if we don't truncate lengths to 0 we might be able to + // easily detect slices with high < low. we'd need to treat -∞ + // specially, though. + for i, l := range ls { + if l.Sign() == -1 { + ls[i] = NewZ(0) + } + } + + return SliceInterval{ + Length: NewIntInterval(MinZ(ls...), MaxZ(ls...)), + } +} +func (c *SliceIntersectionConstraint) Eval(g *Graph) Range { + xi := g.Range(c.X).(SliceInterval) + if !xi.IsKnown() { + return c.I + } + return SliceInterval{ + Length: xi.Length.Intersection(c.I), + } +} +func (c *SliceLengthConstraint) Eval(g *Graph) Range { + i := g.Range(c.X).(SliceInterval).Length + if !i.IsKnown() { + return NewIntInterval(NewZ(0), PInfinity) + } + return i +} +func (c *MakeSliceConstraint) Eval(g *Graph) Range { + i, ok := g.Range(c.Size).(IntInterval) + if !ok { + return SliceInterval{NewIntInterval(NewZ(0), PInfinity)} + } + if i.Lower.Sign() == -1 { + i.Lower = NewZ(0) + } + return SliceInterval{i} +} +func (c *SliceIntervalConstraint) Eval(*Graph) Range { return SliceInterval{c.I} } diff --git a/vendor/honnef.co/go/tools/staticcheck/vrp/string.go b/vendor/honnef.co/go/tools/staticcheck/vrp/string.go new file mode 100644 index 0000000..e05877f --- /dev/null +++ b/vendor/honnef.co/go/tools/staticcheck/vrp/string.go @@ -0,0 +1,258 @@ +package vrp + +import ( + "fmt" + "go/token" + "go/types" + + "honnef.co/go/tools/ssa" +) + +type StringInterval struct { + Length IntInterval +} + +func (s StringInterval) Union(other Range) Range { + i, ok := other.(StringInterval) + if !ok { + i = StringInterval{EmptyIntInterval} + } + if s.Length.Empty() || !s.Length.IsKnown() { + return i + } + if i.Length.Empty() || !i.Length.IsKnown() { + return s + } + return StringInterval{ + Length: s.Length.Union(i.Length).(IntInterval), + } +} + +func (s StringInterval) String() string { + return s.Length.String() +} + +func (s StringInterval) IsKnown() bool { + return s.Length.IsKnown() +} + +type StringSliceConstraint struct { + aConstraint + X ssa.Value + Lower ssa.Value + Upper ssa.Value +} + +type StringIntersectionConstraint struct { + aConstraint + ranges Ranges + A ssa.Value + B ssa.Value + Op token.Token + I IntInterval + resolved bool +} + +type StringConcatConstraint struct { + aConstraint + A ssa.Value + B ssa.Value +} + +type StringLengthConstraint struct { + aConstraint + X ssa.Value +} + +type StringIntervalConstraint struct { + aConstraint + I IntInterval +} + +func NewStringSliceConstraint(x, lower, upper, y ssa.Value) Constraint { + return &StringSliceConstraint{NewConstraint(y), x, lower, upper} +} +func NewStringIntersectionConstraint(a, b ssa.Value, op token.Token, ranges Ranges, y ssa.Value) Constraint { + return &StringIntersectionConstraint{ + aConstraint: NewConstraint(y), + ranges: ranges, + A: a, + B: b, + Op: op, + } +} +func NewStringConcatConstraint(a, b, y ssa.Value) Constraint { + return &StringConcatConstraint{NewConstraint(y), a, b} +} +func NewStringLengthConstraint(x ssa.Value, y ssa.Value) Constraint { + return &StringLengthConstraint{NewConstraint(y), x} +} +func NewStringIntervalConstraint(i IntInterval, y ssa.Value) Constraint { + return &StringIntervalConstraint{NewConstraint(y), i} +} + +func (c *StringSliceConstraint) Operands() []ssa.Value { + vs := []ssa.Value{c.X} + if c.Lower != nil { + vs = append(vs, c.Lower) + } + if c.Upper != nil { + vs = append(vs, c.Upper) + } + return vs +} +func (c *StringIntersectionConstraint) Operands() []ssa.Value { return []ssa.Value{c.A} } +func (c StringConcatConstraint) Operands() []ssa.Value { return []ssa.Value{c.A, c.B} } +func (c *StringLengthConstraint) Operands() []ssa.Value { return []ssa.Value{c.X} } +func (s *StringIntervalConstraint) Operands() []ssa.Value { return nil } + +func (c *StringSliceConstraint) String() string { + var lname, uname string + if c.Lower != nil { + lname = c.Lower.Name() + } + if c.Upper != nil { + uname = c.Upper.Name() + } + return fmt.Sprintf("%s[%s:%s]", c.X.Name(), lname, uname) +} +func (c *StringIntersectionConstraint) String() string { + return fmt.Sprintf("%s = %s %s %s (%t branch)", c.Y().Name(), c.A.Name(), c.Op, c.B.Name(), c.Y().(*ssa.Sigma).Branch) +} +func (c StringConcatConstraint) String() string { + return fmt.Sprintf("%s = %s + %s", c.Y().Name(), c.A.Name(), c.B.Name()) +} +func (c *StringLengthConstraint) String() string { + return fmt.Sprintf("%s = len(%s)", c.Y().Name(), c.X.Name()) +} +func (c *StringIntervalConstraint) String() string { return fmt.Sprintf("%s = %s", c.Y().Name(), c.I) } + +func (c *StringSliceConstraint) Eval(g *Graph) Range { + lr := NewIntInterval(NewZ(0), NewZ(0)) + if c.Lower != nil { + lr = g.Range(c.Lower).(IntInterval) + } + ur := g.Range(c.X).(StringInterval).Length + if c.Upper != nil { + ur = g.Range(c.Upper).(IntInterval) + } + if !lr.IsKnown() || !ur.IsKnown() { + return StringInterval{} + } + + ls := []Z{ + ur.Lower.Sub(lr.Lower), + ur.Upper.Sub(lr.Lower), + ur.Lower.Sub(lr.Upper), + ur.Upper.Sub(lr.Upper), + } + // TODO(dh): if we don't truncate lengths to 0 we might be able to + // easily detect slices with high < low. we'd need to treat -∞ + // specially, though. + for i, l := range ls { + if l.Sign() == -1 { + ls[i] = NewZ(0) + } + } + + return StringInterval{ + Length: NewIntInterval(MinZ(ls...), MaxZ(ls...)), + } +} +func (c *StringIntersectionConstraint) Eval(g *Graph) Range { + var l IntInterval + switch r := g.Range(c.A).(type) { + case StringInterval: + l = r.Length + case IntInterval: + l = r + } + + if !l.IsKnown() { + return StringInterval{c.I} + } + return StringInterval{ + Length: l.Intersection(c.I), + } +} +func (c StringConcatConstraint) Eval(g *Graph) Range { + i1, i2 := g.Range(c.A).(StringInterval), g.Range(c.B).(StringInterval) + if !i1.Length.IsKnown() || !i2.Length.IsKnown() { + return StringInterval{} + } + return StringInterval{ + Length: i1.Length.Add(i2.Length), + } +} +func (c *StringLengthConstraint) Eval(g *Graph) Range { + i := g.Range(c.X).(StringInterval).Length + if !i.IsKnown() { + return NewIntInterval(NewZ(0), PInfinity) + } + return i +} +func (c *StringIntervalConstraint) Eval(*Graph) Range { return StringInterval{c.I} } + +func (c *StringIntersectionConstraint) Futures() []ssa.Value { + return []ssa.Value{c.B} +} + +func (c *StringIntersectionConstraint) Resolve() { + if (c.A.Type().Underlying().(*types.Basic).Info() & types.IsString) != 0 { + // comparing two strings + r, ok := c.ranges[c.B].(StringInterval) + if !ok { + c.I = NewIntInterval(NewZ(0), PInfinity) + return + } + switch c.Op { + case token.EQL: + c.I = r.Length + case token.GTR, token.GEQ: + c.I = NewIntInterval(r.Length.Lower, PInfinity) + case token.LSS, token.LEQ: + c.I = NewIntInterval(NewZ(0), r.Length.Upper) + case token.NEQ: + default: + panic("unsupported op " + c.Op.String()) + } + } else { + r, ok := c.ranges[c.B].(IntInterval) + if !ok { + c.I = NewIntInterval(NewZ(0), PInfinity) + return + } + // comparing two lengths + switch c.Op { + case token.EQL: + c.I = r + case token.GTR: + c.I = NewIntInterval(r.Lower.Add(NewZ(1)), PInfinity) + case token.GEQ: + c.I = NewIntInterval(r.Lower, PInfinity) + case token.LSS: + c.I = NewIntInterval(NInfinity, r.Upper.Sub(NewZ(1))) + case token.LEQ: + c.I = NewIntInterval(NInfinity, r.Upper) + case token.NEQ: + default: + panic("unsupported op " + c.Op.String()) + } + } +} + +func (c *StringIntersectionConstraint) IsKnown() bool { + return c.I.IsKnown() +} + +func (c *StringIntersectionConstraint) MarkUnresolved() { + c.resolved = false +} + +func (c *StringIntersectionConstraint) MarkResolved() { + c.resolved = true +} + +func (c *StringIntersectionConstraint) IsResolved() bool { + return c.resolved +} diff --git a/vendor/honnef.co/go/tools/staticcheck/vrp/vrp.go b/vendor/honnef.co/go/tools/staticcheck/vrp/vrp.go new file mode 100644 index 0000000..cb17f04 --- /dev/null +++ b/vendor/honnef.co/go/tools/staticcheck/vrp/vrp.go @@ -0,0 +1,1049 @@ +package vrp + +// TODO(dh) widening and narrowing have a lot of code in common. Make +// it reusable. + +import ( + "fmt" + "go/constant" + "go/token" + "go/types" + "math/big" + "sort" + "strings" + + "honnef.co/go/tools/ssa" +) + +type Future interface { + Constraint + Futures() []ssa.Value + Resolve() + IsKnown() bool + MarkUnresolved() + MarkResolved() + IsResolved() bool +} + +type Range interface { + Union(other Range) Range + IsKnown() bool +} + +type Constraint interface { + Y() ssa.Value + isConstraint() + String() string + Eval(*Graph) Range + Operands() []ssa.Value +} + +type aConstraint struct { + y ssa.Value +} + +func NewConstraint(y ssa.Value) aConstraint { + return aConstraint{y} +} + +func (aConstraint) isConstraint() {} +func (c aConstraint) Y() ssa.Value { return c.y } + +type PhiConstraint struct { + aConstraint + Vars []ssa.Value +} + +func NewPhiConstraint(vars []ssa.Value, y ssa.Value) Constraint { + uniqm := map[ssa.Value]struct{}{} + for _, v := range vars { + uniqm[v] = struct{}{} + } + var uniq []ssa.Value + for v := range uniqm { + uniq = append(uniq, v) + } + return &PhiConstraint{ + aConstraint: NewConstraint(y), + Vars: uniq, + } +} + +func (c *PhiConstraint) Operands() []ssa.Value { + return c.Vars +} + +func (c *PhiConstraint) Eval(g *Graph) Range { + i := Range(nil) + for _, v := range c.Vars { + i = g.Range(v).Union(i) + } + return i +} + +func (c *PhiConstraint) String() string { + names := make([]string, len(c.Vars)) + for i, v := range c.Vars { + names[i] = v.Name() + } + return fmt.Sprintf("%s = φ(%s)", c.Y().Name(), strings.Join(names, ", ")) +} + +func isSupportedType(typ types.Type) bool { + switch typ := typ.Underlying().(type) { + case *types.Basic: + switch typ.Kind() { + case types.String, types.UntypedString: + return true + default: + if (typ.Info() & types.IsInteger) == 0 { + return false + } + } + case *types.Chan: + return true + case *types.Slice: + return true + default: + return false + } + return true +} + +func ConstantToZ(c constant.Value) Z { + s := constant.ToInt(c).ExactString() + n := &big.Int{} + n.SetString(s, 10) + return NewBigZ(n) +} + +func sigmaInteger(g *Graph, ins *ssa.Sigma, cond *ssa.BinOp, ops []*ssa.Value) Constraint { + op := cond.Op + if !ins.Branch { + op = (invertToken(op)) + } + + switch op { + case token.EQL, token.GTR, token.GEQ, token.LSS, token.LEQ: + default: + return nil + } + var a, b ssa.Value + if (*ops[0]) == ins.X { + a = *ops[0] + b = *ops[1] + } else { + a = *ops[1] + b = *ops[0] + op = flipToken(op) + } + return NewIntIntersectionConstraint(a, b, op, g.ranges, ins) +} + +func sigmaString(g *Graph, ins *ssa.Sigma, cond *ssa.BinOp, ops []*ssa.Value) Constraint { + op := cond.Op + if !ins.Branch { + op = (invertToken(op)) + } + + switch op { + case token.EQL, token.GTR, token.GEQ, token.LSS, token.LEQ: + default: + return nil + } + + if ((*ops[0]).Type().Underlying().(*types.Basic).Info() & types.IsString) == 0 { + var a, b ssa.Value + call, ok := (*ops[0]).(*ssa.Call) + if ok && call.Common().Args[0] == ins.X { + a = *ops[0] + b = *ops[1] + } else { + a = *ops[1] + b = *ops[0] + op = flipToken(op) + } + return NewStringIntersectionConstraint(a, b, op, g.ranges, ins) + } + var a, b ssa.Value + if (*ops[0]) == ins.X { + a = *ops[0] + b = *ops[1] + } else { + a = *ops[1] + b = *ops[0] + op = flipToken(op) + } + return NewStringIntersectionConstraint(a, b, op, g.ranges, ins) +} + +func sigmaSlice(g *Graph, ins *ssa.Sigma, cond *ssa.BinOp, ops []*ssa.Value) Constraint { + // TODO(dh) sigmaSlice and sigmaString are a lot alike. Can they + // be merged? + // + // XXX support futures + + op := cond.Op + if !ins.Branch { + op = (invertToken(op)) + } + + k, ok := (*ops[1]).(*ssa.Const) + // XXX investigate in what cases this wouldn't be a Const + // + // XXX what if left and right are swapped? + if !ok { + return nil + } + + call, ok := (*ops[0]).(*ssa.Call) + if !ok { + return nil + } + builtin, ok := call.Common().Value.(*ssa.Builtin) + if !ok { + return nil + } + if builtin.Name() != "len" { + return nil + } + callops := call.Operands(nil) + + v := ConstantToZ(k.Value) + c := NewSliceIntersectionConstraint(*callops[1], IntInterval{}, ins).(*SliceIntersectionConstraint) + switch op { + case token.EQL: + c.I = NewIntInterval(v, v) + case token.GTR, token.GEQ: + off := int64(0) + if cond.Op == token.GTR { + off = 1 + } + c.I = NewIntInterval( + v.Add(NewZ(off)), + PInfinity, + ) + case token.LSS, token.LEQ: + off := int64(0) + if cond.Op == token.LSS { + off = -1 + } + c.I = NewIntInterval( + NInfinity, + v.Add(NewZ(off)), + ) + default: + return nil + } + return c +} + +func BuildGraph(f *ssa.Function) *Graph { + g := &Graph{ + Vertices: map[interface{}]*Vertex{}, + ranges: Ranges{}, + } + + var cs []Constraint + + ops := make([]*ssa.Value, 16) + seen := map[ssa.Value]bool{} + for _, block := range f.Blocks { + for _, ins := range block.Instrs { + ops = ins.Operands(ops[:0]) + for _, op := range ops { + if c, ok := (*op).(*ssa.Const); ok { + if seen[c] { + continue + } + seen[c] = true + if c.Value == nil { + switch c.Type().Underlying().(type) { + case *types.Slice: + cs = append(cs, NewSliceIntervalConstraint(NewIntInterval(NewZ(0), NewZ(0)), c)) + } + continue + } + switch c.Value.Kind() { + case constant.Int: + v := ConstantToZ(c.Value) + cs = append(cs, NewIntIntervalConstraint(NewIntInterval(v, v), c)) + case constant.String: + s := constant.StringVal(c.Value) + n := NewZ(int64(len(s))) + cs = append(cs, NewStringIntervalConstraint(NewIntInterval(n, n), c)) + } + } + } + } + } + for _, block := range f.Blocks { + for _, ins := range block.Instrs { + switch ins := ins.(type) { + case *ssa.Convert: + switch v := ins.Type().Underlying().(type) { + case *types.Basic: + if (v.Info() & types.IsInteger) == 0 { + continue + } + cs = append(cs, NewIntConversionConstraint(ins.X, ins)) + } + case *ssa.Call: + if static := ins.Common().StaticCallee(); static != nil { + if fn, ok := static.Object().(*types.Func); ok { + switch fn.FullName() { + case "bytes.Index", "bytes.IndexAny", "bytes.IndexByte", + "bytes.IndexFunc", "bytes.IndexRune", "bytes.LastIndex", + "bytes.LastIndexAny", "bytes.LastIndexByte", "bytes.LastIndexFunc", + "strings.Index", "strings.IndexAny", "strings.IndexByte", + "strings.IndexFunc", "strings.IndexRune", "strings.LastIndex", + "strings.LastIndexAny", "strings.LastIndexByte", "strings.LastIndexFunc": + // TODO(dh): instead of limiting by +∞, + // limit by the upper bound of the passed + // string + cs = append(cs, NewIntIntervalConstraint(NewIntInterval(NewZ(-1), PInfinity), ins)) + case "bytes.Title", "bytes.ToLower", "bytes.ToTitle", "bytes.ToUpper", + "strings.Title", "strings.ToLower", "strings.ToTitle", "strings.ToUpper": + cs = append(cs, NewCopyConstraint(ins.Common().Args[0], ins)) + case "bytes.ToLowerSpecial", "bytes.ToTitleSpecial", "bytes.ToUpperSpecial", + "strings.ToLowerSpecial", "strings.ToTitleSpecial", "strings.ToUpperSpecial": + cs = append(cs, NewCopyConstraint(ins.Common().Args[1], ins)) + case "bytes.Compare", "strings.Compare": + cs = append(cs, NewIntIntervalConstraint(NewIntInterval(NewZ(-1), NewZ(1)), ins)) + case "bytes.Count", "strings.Count": + // TODO(dh): instead of limiting by +∞, + // limit by the upper bound of the passed + // string. + cs = append(cs, NewIntIntervalConstraint(NewIntInterval(NewZ(0), PInfinity), ins)) + case "bytes.Map", "bytes.TrimFunc", "bytes.TrimLeft", "bytes.TrimLeftFunc", + "bytes.TrimRight", "bytes.TrimRightFunc", "bytes.TrimSpace", + "strings.Map", "strings.TrimFunc", "strings.TrimLeft", "strings.TrimLeftFunc", + "strings.TrimRight", "strings.TrimRightFunc", "strings.TrimSpace": + // TODO(dh): lower = 0, upper = upper of passed string + case "bytes.TrimPrefix", "bytes.TrimSuffix", + "strings.TrimPrefix", "strings.TrimSuffix": + // TODO(dh) range between "unmodified" and len(cutset) removed + case "(*bytes.Buffer).Cap", "(*bytes.Buffer).Len", "(*bytes.Reader).Len", "(*bytes.Reader).Size": + cs = append(cs, NewIntIntervalConstraint(NewIntInterval(NewZ(0), PInfinity), ins)) + } + } + } + builtin, ok := ins.Common().Value.(*ssa.Builtin) + ops := ins.Operands(nil) + if !ok { + continue + } + switch builtin.Name() { + case "len": + switch op1 := (*ops[1]).Type().Underlying().(type) { + case *types.Basic: + if op1.Kind() == types.String || op1.Kind() == types.UntypedString { + cs = append(cs, NewStringLengthConstraint(*ops[1], ins)) + } + case *types.Slice: + cs = append(cs, NewSliceLengthConstraint(*ops[1], ins)) + } + + case "append": + cs = append(cs, NewSliceAppendConstraint(ins.Common().Args[0], ins.Common().Args[1], ins)) + } + case *ssa.BinOp: + ops := ins.Operands(nil) + basic, ok := (*ops[0]).Type().Underlying().(*types.Basic) + if !ok { + continue + } + switch basic.Kind() { + case types.Int, types.Int8, types.Int16, types.Int32, types.Int64, + types.Uint, types.Uint8, types.Uint16, types.Uint32, types.Uint64, types.UntypedInt: + fns := map[token.Token]func(ssa.Value, ssa.Value, ssa.Value) Constraint{ + token.ADD: NewIntAddConstraint, + token.SUB: NewIntSubConstraint, + token.MUL: NewIntMulConstraint, + // XXX support QUO, REM, SHL, SHR + } + fn, ok := fns[ins.Op] + if ok { + cs = append(cs, fn(*ops[0], *ops[1], ins)) + } + case types.String, types.UntypedString: + if ins.Op == token.ADD { + cs = append(cs, NewStringConcatConstraint(*ops[0], *ops[1], ins)) + } + } + case *ssa.Slice: + typ := ins.X.Type().Underlying() + switch typ := typ.(type) { + case *types.Basic: + cs = append(cs, NewStringSliceConstraint(ins.X, ins.Low, ins.High, ins)) + case *types.Slice: + cs = append(cs, NewSliceSliceConstraint(ins.X, ins.Low, ins.High, ins)) + case *types.Array: + cs = append(cs, NewArraySliceConstraint(ins.X, ins.Low, ins.High, ins)) + case *types.Pointer: + if _, ok := typ.Elem().(*types.Array); !ok { + continue + } + cs = append(cs, NewArraySliceConstraint(ins.X, ins.Low, ins.High, ins)) + } + case *ssa.Phi: + if !isSupportedType(ins.Type()) { + continue + } + ops := ins.Operands(nil) + dops := make([]ssa.Value, len(ops)) + for i, op := range ops { + dops[i] = *op + } + cs = append(cs, NewPhiConstraint(dops, ins)) + case *ssa.Sigma: + pred := ins.Block().Preds[0] + instrs := pred.Instrs + cond, ok := instrs[len(instrs)-1].(*ssa.If).Cond.(*ssa.BinOp) + ops := cond.Operands(nil) + if !ok { + continue + } + switch typ := ins.Type().Underlying().(type) { + case *types.Basic: + var c Constraint + switch typ.Kind() { + case types.Int, types.Int8, types.Int16, types.Int32, types.Int64, + types.Uint, types.Uint8, types.Uint16, types.Uint32, types.Uint64, types.UntypedInt: + c = sigmaInteger(g, ins, cond, ops) + case types.String, types.UntypedString: + c = sigmaString(g, ins, cond, ops) + } + if c != nil { + cs = append(cs, c) + } + case *types.Slice: + c := sigmaSlice(g, ins, cond, ops) + if c != nil { + cs = append(cs, c) + } + default: + //log.Printf("unsupported sigma type %T", typ) // XXX + } + case *ssa.MakeChan: + cs = append(cs, NewMakeChannelConstraint(ins.Size, ins)) + case *ssa.MakeSlice: + cs = append(cs, NewMakeSliceConstraint(ins.Len, ins)) + case *ssa.ChangeType: + switch ins.X.Type().Underlying().(type) { + case *types.Chan: + cs = append(cs, NewChannelChangeTypeConstraint(ins.X, ins)) + } + } + } + } + + for _, c := range cs { + if c == nil { + panic("nil constraint") + } + // If V is used in constraint C, then we create an edge V->C + for _, op := range c.Operands() { + g.AddEdge(op, c, false) + } + if c, ok := c.(Future); ok { + for _, op := range c.Futures() { + g.AddEdge(op, c, true) + } + } + // If constraint C defines variable V, then we create an edge + // C->V + g.AddEdge(c, c.Y(), false) + } + + g.FindSCCs() + g.sccEdges = make([][]Edge, len(g.SCCs)) + g.futures = make([][]Future, len(g.SCCs)) + for _, e := range g.Edges { + g.sccEdges[e.From.SCC] = append(g.sccEdges[e.From.SCC], e) + if !e.control { + continue + } + if c, ok := e.To.Value.(Future); ok { + g.futures[e.From.SCC] = append(g.futures[e.From.SCC], c) + } + } + return g +} + +func (g *Graph) Solve() Ranges { + var consts []Z + off := NewZ(1) + for _, n := range g.Vertices { + if c, ok := n.Value.(*ssa.Const); ok { + basic, ok := c.Type().Underlying().(*types.Basic) + if !ok { + continue + } + if (basic.Info() & types.IsInteger) != 0 { + z := ConstantToZ(c.Value) + consts = append(consts, z) + consts = append(consts, z.Add(off)) + consts = append(consts, z.Sub(off)) + } + } + + } + sort.Sort(Zs(consts)) + + for scc, vertices := range g.SCCs { + n := 0 + n = len(vertices) + if n == 1 { + g.resolveFutures(scc) + v := vertices[0] + if v, ok := v.Value.(ssa.Value); ok { + switch typ := v.Type().Underlying().(type) { + case *types.Basic: + switch typ.Kind() { + case types.String, types.UntypedString: + if !g.Range(v).(StringInterval).IsKnown() { + g.SetRange(v, StringInterval{NewIntInterval(NewZ(0), PInfinity)}) + } + default: + if !g.Range(v).(IntInterval).IsKnown() { + g.SetRange(v, InfinityFor(v)) + } + } + case *types.Chan: + if !g.Range(v).(ChannelInterval).IsKnown() { + g.SetRange(v, ChannelInterval{NewIntInterval(NewZ(0), PInfinity)}) + } + case *types.Slice: + if !g.Range(v).(SliceInterval).IsKnown() { + g.SetRange(v, SliceInterval{NewIntInterval(NewZ(0), PInfinity)}) + } + } + } + if c, ok := v.Value.(Constraint); ok { + g.SetRange(c.Y(), c.Eval(g)) + } + } else { + uses := g.uses(scc) + entries := g.entries(scc) + for len(entries) > 0 { + v := entries[len(entries)-1] + entries = entries[:len(entries)-1] + for _, use := range uses[v] { + if g.widen(use, consts) { + entries = append(entries, use.Y()) + } + } + } + + g.resolveFutures(scc) + + // XXX this seems to be necessary, but shouldn't be. + // removing it leads to nil pointer derefs; investigate + // where we're not setting values correctly. + for _, n := range vertices { + if v, ok := n.Value.(ssa.Value); ok { + i, ok := g.Range(v).(IntInterval) + if !ok { + continue + } + if !i.IsKnown() { + g.SetRange(v, InfinityFor(v)) + } + } + } + + actives := g.actives(scc) + for len(actives) > 0 { + v := actives[len(actives)-1] + actives = actives[:len(actives)-1] + for _, use := range uses[v] { + if g.narrow(use) { + actives = append(actives, use.Y()) + } + } + } + } + // propagate scc + for _, edge := range g.sccEdges[scc] { + if edge.control { + continue + } + if edge.From.SCC == edge.To.SCC { + continue + } + if c, ok := edge.To.Value.(Constraint); ok { + g.SetRange(c.Y(), c.Eval(g)) + } + if c, ok := edge.To.Value.(Future); ok { + if !c.IsKnown() { + c.MarkUnresolved() + } + } + } + } + + for v, r := range g.ranges { + i, ok := r.(IntInterval) + if !ok { + continue + } + if (v.Type().Underlying().(*types.Basic).Info() & types.IsUnsigned) == 0 { + if i.Upper != PInfinity { + s := &types.StdSizes{ + // XXX is it okay to assume the largest word size, or do we + // need to be platform specific? + WordSize: 8, + MaxAlign: 1, + } + bits := (s.Sizeof(v.Type()) * 8) - 1 + n := big.NewInt(1) + n = n.Lsh(n, uint(bits)) + upper, lower := &big.Int{}, &big.Int{} + upper.Sub(n, big.NewInt(1)) + lower.Neg(n) + + if i.Upper.Cmp(NewBigZ(upper)) == 1 { + i = NewIntInterval(NInfinity, PInfinity) + } else if i.Lower.Cmp(NewBigZ(lower)) == -1 { + i = NewIntInterval(NInfinity, PInfinity) + } + } + } + + g.ranges[v] = i + } + + return g.ranges +} + +func VertexString(v *Vertex) string { + switch v := v.Value.(type) { + case Constraint: + return v.String() + case ssa.Value: + return v.Name() + case nil: + return "BUG: nil vertex value" + default: + panic(fmt.Sprintf("unexpected type %T", v)) + } +} + +type Vertex struct { + Value interface{} // one of Constraint or ssa.Value + SCC int + index int + lowlink int + stack bool + + Succs []Edge +} + +type Ranges map[ssa.Value]Range + +func (r Ranges) Get(x ssa.Value) Range { + if x == nil { + return nil + } + i, ok := r[x] + if !ok { + switch x := x.Type().Underlying().(type) { + case *types.Basic: + switch x.Kind() { + case types.String, types.UntypedString: + return StringInterval{} + default: + return IntInterval{} + } + case *types.Chan: + return ChannelInterval{} + case *types.Slice: + return SliceInterval{} + } + } + return i +} + +type Graph struct { + Vertices map[interface{}]*Vertex + Edges []Edge + SCCs [][]*Vertex + ranges Ranges + + // map SCCs to futures + futures [][]Future + // map SCCs to edges + sccEdges [][]Edge +} + +func (g Graph) Graphviz() string { + var lines []string + lines = append(lines, "digraph{") + ids := map[interface{}]int{} + i := 1 + for _, v := range g.Vertices { + ids[v] = i + shape := "box" + if _, ok := v.Value.(ssa.Value); ok { + shape = "oval" + } + lines = append(lines, fmt.Sprintf(`n%d [shape="%s", label=%q, colorscheme=spectral11, style="filled", fillcolor="%d"]`, + i, shape, VertexString(v), (v.SCC%11)+1)) + i++ + } + for _, e := range g.Edges { + style := "solid" + if e.control { + style = "dashed" + } + lines = append(lines, fmt.Sprintf(`n%d -> n%d [style="%s"]`, ids[e.From], ids[e.To], style)) + } + lines = append(lines, "}") + return strings.Join(lines, "\n") +} + +func (g *Graph) SetRange(x ssa.Value, r Range) { + g.ranges[x] = r +} + +func (g *Graph) Range(x ssa.Value) Range { + return g.ranges.Get(x) +} + +func (g *Graph) widen(c Constraint, consts []Z) bool { + setRange := func(i Range) { + g.SetRange(c.Y(), i) + } + widenIntInterval := func(oi, ni IntInterval) (IntInterval, bool) { + if !ni.IsKnown() { + return oi, false + } + nlc := NInfinity + nuc := PInfinity + for _, co := range consts { + if co.Cmp(ni.Lower) <= 0 { + nlc = co + break + } + } + for _, co := range consts { + if co.Cmp(ni.Upper) >= 0 { + nuc = co + break + } + } + + if !oi.IsKnown() { + return ni, true + } + if ni.Lower.Cmp(oi.Lower) == -1 && ni.Upper.Cmp(oi.Upper) == 1 { + return NewIntInterval(nlc, nuc), true + } + if ni.Lower.Cmp(oi.Lower) == -1 { + return NewIntInterval(nlc, oi.Upper), true + } + if ni.Upper.Cmp(oi.Upper) == 1 { + return NewIntInterval(oi.Lower, nuc), true + } + return oi, false + } + switch oi := g.Range(c.Y()).(type) { + case IntInterval: + ni := c.Eval(g).(IntInterval) + si, changed := widenIntInterval(oi, ni) + if changed { + setRange(si) + return true + } + return false + case StringInterval: + ni := c.Eval(g).(StringInterval) + si, changed := widenIntInterval(oi.Length, ni.Length) + if changed { + setRange(StringInterval{si}) + return true + } + return false + case SliceInterval: + ni := c.Eval(g).(SliceInterval) + si, changed := widenIntInterval(oi.Length, ni.Length) + if changed { + setRange(SliceInterval{si}) + return true + } + return false + default: + return false + } +} + +func (g *Graph) narrow(c Constraint) bool { + narrowIntInterval := func(oi, ni IntInterval) (IntInterval, bool) { + oLower := oi.Lower + oUpper := oi.Upper + nLower := ni.Lower + nUpper := ni.Upper + + if oLower == NInfinity && nLower != NInfinity { + return NewIntInterval(nLower, oUpper), true + } + if oUpper == PInfinity && nUpper != PInfinity { + return NewIntInterval(oLower, nUpper), true + } + if oLower.Cmp(nLower) == 1 { + return NewIntInterval(nLower, oUpper), true + } + if oUpper.Cmp(nUpper) == -1 { + return NewIntInterval(oLower, nUpper), true + } + return oi, false + } + switch oi := g.Range(c.Y()).(type) { + case IntInterval: + ni := c.Eval(g).(IntInterval) + si, changed := narrowIntInterval(oi, ni) + if changed { + g.SetRange(c.Y(), si) + return true + } + return false + case StringInterval: + ni := c.Eval(g).(StringInterval) + si, changed := narrowIntInterval(oi.Length, ni.Length) + if changed { + g.SetRange(c.Y(), StringInterval{si}) + return true + } + return false + case SliceInterval: + ni := c.Eval(g).(SliceInterval) + si, changed := narrowIntInterval(oi.Length, ni.Length) + if changed { + g.SetRange(c.Y(), SliceInterval{si}) + return true + } + return false + default: + return false + } +} + +func (g *Graph) resolveFutures(scc int) { + for _, c := range g.futures[scc] { + c.Resolve() + } +} + +func (g *Graph) entries(scc int) []ssa.Value { + var entries []ssa.Value + for _, n := range g.Vertices { + if n.SCC != scc { + continue + } + if v, ok := n.Value.(ssa.Value); ok { + // XXX avoid quadratic runtime + // + // XXX I cannot think of any code where the future and its + // variables aren't in the same SCC, in which case this + // code isn't very useful (the variables won't be resolved + // yet). Before we have a cross-SCC example, however, we + // can't really verify that this code is working + // correctly, or indeed doing anything useful. + for _, on := range g.Vertices { + if c, ok := on.Value.(Future); ok { + if c.Y() == v { + if !c.IsResolved() { + g.SetRange(c.Y(), c.Eval(g)) + c.MarkResolved() + } + break + } + } + } + if g.Range(v).IsKnown() { + entries = append(entries, v) + } + } + } + return entries +} + +func (g *Graph) uses(scc int) map[ssa.Value][]Constraint { + m := map[ssa.Value][]Constraint{} + for _, e := range g.sccEdges[scc] { + if e.control { + continue + } + if v, ok := e.From.Value.(ssa.Value); ok { + c := e.To.Value.(Constraint) + sink := c.Y() + if g.Vertices[sink].SCC == scc { + m[v] = append(m[v], c) + } + } + } + return m +} + +func (g *Graph) actives(scc int) []ssa.Value { + var actives []ssa.Value + for _, n := range g.Vertices { + if n.SCC != scc { + continue + } + if v, ok := n.Value.(ssa.Value); ok { + if _, ok := v.(*ssa.Const); !ok { + actives = append(actives, v) + } + } + } + return actives +} + +func (g *Graph) AddEdge(from, to interface{}, ctrl bool) { + vf, ok := g.Vertices[from] + if !ok { + vf = &Vertex{Value: from} + g.Vertices[from] = vf + } + vt, ok := g.Vertices[to] + if !ok { + vt = &Vertex{Value: to} + g.Vertices[to] = vt + } + e := Edge{From: vf, To: vt, control: ctrl} + g.Edges = append(g.Edges, e) + vf.Succs = append(vf.Succs, e) +} + +type Edge struct { + From, To *Vertex + control bool +} + +func (e Edge) String() string { + return fmt.Sprintf("%s -> %s", VertexString(e.From), VertexString(e.To)) +} + +func (g *Graph) FindSCCs() { + // use Tarjan to find the SCCs + + index := 1 + var s []*Vertex + + scc := 0 + var strongconnect func(v *Vertex) + strongconnect = func(v *Vertex) { + // set the depth index for v to the smallest unused index + v.index = index + v.lowlink = index + index++ + s = append(s, v) + v.stack = true + + for _, e := range v.Succs { + w := e.To + if w.index == 0 { + // successor w has not yet been visited; recurse on it + strongconnect(w) + if w.lowlink < v.lowlink { + v.lowlink = w.lowlink + } + } else if w.stack { + // successor w is in stack s and hence in the current scc + if w.index < v.lowlink { + v.lowlink = w.index + } + } + } + + if v.lowlink == v.index { + for { + w := s[len(s)-1] + s = s[:len(s)-1] + w.stack = false + w.SCC = scc + if w == v { + break + } + } + scc++ + } + } + for _, v := range g.Vertices { + if v.index == 0 { + strongconnect(v) + } + } + + g.SCCs = make([][]*Vertex, scc) + for _, n := range g.Vertices { + n.SCC = scc - n.SCC - 1 + g.SCCs[n.SCC] = append(g.SCCs[n.SCC], n) + } +} + +func invertToken(tok token.Token) token.Token { + switch tok { + case token.LSS: + return token.GEQ + case token.GTR: + return token.LEQ + case token.EQL: + return token.NEQ + case token.NEQ: + return token.EQL + case token.GEQ: + return token.LSS + case token.LEQ: + return token.GTR + default: + panic(fmt.Sprintf("unsupported token %s", tok)) + } +} + +func flipToken(tok token.Token) token.Token { + switch tok { + case token.LSS: + return token.GTR + case token.GTR: + return token.LSS + case token.EQL: + return token.EQL + case token.NEQ: + return token.NEQ + case token.GEQ: + return token.LEQ + case token.LEQ: + return token.GEQ + default: + panic(fmt.Sprintf("unsupported token %s", tok)) + } +} + +type CopyConstraint struct { + aConstraint + X ssa.Value +} + +func (c *CopyConstraint) String() string { + return fmt.Sprintf("%s = copy(%s)", c.Y().Name(), c.X.Name()) +} + +func (c *CopyConstraint) Eval(g *Graph) Range { + return g.Range(c.X) +} + +func (c *CopyConstraint) Operands() []ssa.Value { + return []ssa.Value{c.X} +} + +func NewCopyConstraint(x, y ssa.Value) Constraint { + return &CopyConstraint{ + aConstraint: aConstraint{ + y: y, + }, + X: x, + } +} diff --git a/vendor/honnef.co/go/tools/unused/unused.go b/vendor/honnef.co/go/tools/unused/unused.go new file mode 100644 index 0000000..21889e8 --- /dev/null +++ b/vendor/honnef.co/go/tools/unused/unused.go @@ -0,0 +1,1064 @@ +package unused // import "honnef.co/go/tools/unused" + +import ( + "fmt" + "go/ast" + "go/token" + "go/types" + "io" + "path/filepath" + "strings" + + "honnef.co/go/tools/lint" + + "golang.org/x/tools/go/loader" + "golang.org/x/tools/go/types/typeutil" +) + +func NewLintChecker(c *Checker) *LintChecker { + l := &LintChecker{ + c: c, + } + return l +} + +type LintChecker struct { + c *Checker +} + +func (*LintChecker) Name() string { return "unused" } +func (*LintChecker) Prefix() string { return "U" } + +func (l *LintChecker) Init(*lint.Program) {} +func (l *LintChecker) Funcs() map[string]lint.Func { + return map[string]lint.Func{ + "U1000": l.Lint, + } +} + +func typString(obj types.Object) string { + switch obj := obj.(type) { + case *types.Func: + return "func" + case *types.Var: + if obj.IsField() { + return "field" + } + return "var" + case *types.Const: + return "const" + case *types.TypeName: + return "type" + default: + // log.Printf("%T", obj) + return "identifier" + } +} + +func (l *LintChecker) Lint(j *lint.Job) { + unused := l.c.Check(j.Program.Prog) + for _, u := range unused { + name := u.Obj.Name() + if sig, ok := u.Obj.Type().(*types.Signature); ok && sig.Recv() != nil { + switch sig.Recv().Type().(type) { + case *types.Named, *types.Pointer: + typ := types.TypeString(sig.Recv().Type(), func(*types.Package) string { return "" }) + if len(typ) > 0 && typ[0] == '*' { + name = fmt.Sprintf("(%s).%s", typ, u.Obj.Name()) + } else if len(typ) > 0 { + name = fmt.Sprintf("%s.%s", typ, u.Obj.Name()) + } + } + } + j.Errorf(u.Obj, "%s %s is unused", typString(u.Obj), name) + } +} + +type graph struct { + roots []*graphNode + nodes map[interface{}]*graphNode +} + +func (g *graph) markUsedBy(obj, usedBy interface{}) { + objNode := g.getNode(obj) + usedByNode := g.getNode(usedBy) + if objNode.obj == usedByNode.obj { + return + } + usedByNode.uses[objNode] = struct{}{} +} + +var labelCounter = 1 + +func (g *graph) getNode(obj interface{}) *graphNode { + for { + if pt, ok := obj.(*types.Pointer); ok { + obj = pt.Elem() + } else { + break + } + } + _, ok := g.nodes[obj] + if !ok { + g.addObj(obj) + } + + return g.nodes[obj] +} + +func (g *graph) addObj(obj interface{}) { + if pt, ok := obj.(*types.Pointer); ok { + obj = pt.Elem() + } + node := &graphNode{obj: obj, uses: make(map[*graphNode]struct{}), n: labelCounter} + g.nodes[obj] = node + labelCounter++ + + if obj, ok := obj.(*types.Struct); ok { + n := obj.NumFields() + for i := 0; i < n; i++ { + field := obj.Field(i) + g.markUsedBy(obj, field) + } + } +} + +type graphNode struct { + obj interface{} + uses map[*graphNode]struct{} + used bool + quiet bool + n int +} + +type CheckMode int + +const ( + CheckConstants CheckMode = 1 << iota + CheckFields + CheckFunctions + CheckTypes + CheckVariables + + CheckAll = CheckConstants | CheckFields | CheckFunctions | CheckTypes | CheckVariables +) + +type Unused struct { + Obj types.Object + Position token.Position +} + +type Checker struct { + Mode CheckMode + WholeProgram bool + ConsiderReflection bool + Debug io.Writer + + graph *graph + + msCache typeutil.MethodSetCache + lprog *loader.Program + topmostCache map[*types.Scope]*types.Scope + interfaces []*types.Interface +} + +func NewChecker(mode CheckMode) *Checker { + return &Checker{ + Mode: mode, + graph: &graph{ + nodes: make(map[interface{}]*graphNode), + }, + topmostCache: make(map[*types.Scope]*types.Scope), + } +} + +func (c *Checker) checkConstants() bool { return (c.Mode & CheckConstants) > 0 } +func (c *Checker) checkFields() bool { return (c.Mode & CheckFields) > 0 } +func (c *Checker) checkFunctions() bool { return (c.Mode & CheckFunctions) > 0 } +func (c *Checker) checkTypes() bool { return (c.Mode & CheckTypes) > 0 } +func (c *Checker) checkVariables() bool { return (c.Mode & CheckVariables) > 0 } + +func (c *Checker) markFields(typ types.Type) { + structType, ok := typ.Underlying().(*types.Struct) + if !ok { + return + } + n := structType.NumFields() + for i := 0; i < n; i++ { + field := structType.Field(i) + c.graph.markUsedBy(field, typ) + } +} + +type Error struct { + Errors map[string][]error +} + +func (e Error) Error() string { + return fmt.Sprintf("errors in %d packages", len(e.Errors)) +} + +func (c *Checker) Check(lprog *loader.Program) []Unused { + var unused []Unused + c.lprog = lprog + if c.WholeProgram { + c.findExportedInterfaces() + } + for _, pkg := range c.lprog.InitialPackages() { + c.processDefs(pkg) + c.processUses(pkg) + c.processTypes(pkg) + c.processSelections(pkg) + c.processAST(pkg) + } + + for _, node := range c.graph.nodes { + obj, ok := node.obj.(types.Object) + if !ok { + continue + } + typNode, ok := c.graph.nodes[obj.Type()] + if !ok { + continue + } + node.uses[typNode] = struct{}{} + } + + roots := map[*graphNode]struct{}{} + for _, root := range c.graph.roots { + roots[root] = struct{}{} + } + markNodesUsed(roots) + c.markNodesQuiet() + + if c.Debug != nil { + c.printDebugGraph(c.Debug) + } + + for _, node := range c.graph.nodes { + if node.used || node.quiet { + continue + } + obj, ok := node.obj.(types.Object) + if !ok { + continue + } + found := false + if !false { + for _, pkg := range c.lprog.InitialPackages() { + if pkg.Pkg == obj.Pkg() { + found = true + break + } + } + } + if !found { + continue + } + + pos := c.lprog.Fset.Position(obj.Pos()) + if pos.Filename == "" || filepath.Base(pos.Filename) == "C" { + continue + } + generated := false + for _, file := range c.lprog.Package(obj.Pkg().Path()).Files { + if c.lprog.Fset.Position(file.Pos()).Filename != pos.Filename { + continue + } + if len(file.Comments) > 0 { + generated = isGenerated(file.Comments[0].Text()) + } + break + } + if generated { + continue + } + unused = append(unused, Unused{Obj: obj, Position: pos}) + } + return unused +} + +// isNoCopyType reports whether a type represents the NoCopy sentinel +// type. The NoCopy type is a named struct with no fields and exactly +// one method `func Lock()` that is empty. +// +// FIXME(dh): currently we're not checking that the function body is +// empty. +func isNoCopyType(typ types.Type) bool { + st, ok := typ.Underlying().(*types.Struct) + if !ok { + return false + } + if st.NumFields() != 0 { + return false + } + + named, ok := typ.(*types.Named) + if !ok { + return false + } + if named.NumMethods() != 1 { + return false + } + meth := named.Method(0) + if meth.Name() != "Lock" { + return false + } + sig := meth.Type().(*types.Signature) + if sig.Params().Len() != 0 || sig.Results().Len() != 0 { + return false + } + return true +} + +func (c *Checker) useNoCopyFields(typ types.Type) { + if st, ok := typ.Underlying().(*types.Struct); ok { + n := st.NumFields() + for i := 0; i < n; i++ { + field := st.Field(i) + if isNoCopyType(field.Type()) { + c.graph.markUsedBy(field, typ) + c.graph.markUsedBy(field.Type().(*types.Named).Method(0), field.Type()) + } + } + } +} + +func (c *Checker) useExportedFields(typ types.Type) { + if st, ok := typ.Underlying().(*types.Struct); ok { + n := st.NumFields() + for i := 0; i < n; i++ { + field := st.Field(i) + if field.Exported() { + c.graph.markUsedBy(field, typ) + } + } + } +} + +func (c *Checker) useExportedMethods(typ types.Type) { + named, ok := typ.(*types.Named) + if !ok { + return + } + ms := typeutil.IntuitiveMethodSet(named, &c.msCache) + for i := 0; i < len(ms); i++ { + meth := ms[i].Obj() + if meth.Exported() { + c.graph.markUsedBy(meth, typ) + } + } + + st, ok := named.Underlying().(*types.Struct) + if !ok { + return + } + n := st.NumFields() + for i := 0; i < n; i++ { + field := st.Field(i) + if !field.Anonymous() { + continue + } + ms := typeutil.IntuitiveMethodSet(field.Type(), &c.msCache) + for j := 0; j < len(ms); j++ { + if ms[j].Obj().Exported() { + c.graph.markUsedBy(field, typ) + break + } + } + } +} + +func (c *Checker) processDefs(pkg *loader.PackageInfo) { + for _, obj := range pkg.Defs { + if obj == nil { + continue + } + c.graph.getNode(obj) + + if obj, ok := obj.(*types.TypeName); ok { + c.graph.markUsedBy(obj.Type().Underlying(), obj.Type()) + c.graph.markUsedBy(obj.Type(), obj) // TODO is this needed? + c.graph.markUsedBy(obj, obj.Type()) + + // We mark all exported fields as used. For normal + // operation, we have to. The user may use these fields + // without us knowing. + // + // TODO(dh): In whole-program mode, however, we mark them + // as used because of reflection (such as JSON + // marshaling). Strictly speaking, we would only need to + // mark them used if an instance of the type was + // accessible via an interface value. + if !c.WholeProgram || c.ConsiderReflection { + c.useExportedFields(obj.Type()) + } + + // TODO(dh): Traditionally we have not marked all exported + // methods as exported, even though they're strictly + // speaking accessible through reflection. We've done that + // because using methods just via reflection is rare, and + // not worth the false negatives. With the new -reflect + // flag, however, we should reconsider that choice. + if !c.WholeProgram { + c.useExportedMethods(obj.Type()) + } + } + + switch obj := obj.(type) { + case *types.Var, *types.Const, *types.Func, *types.TypeName: + if obj.Exported() { + // Exported variables and constants use their types, + // even if there's no expression using them in the + // checked program. + // + // Also operates on funcs and type names, but that's + // irrelevant/redundant. + c.graph.markUsedBy(obj.Type(), obj) + } + if obj.Name() == "_" { + node := c.graph.getNode(obj) + node.quiet = true + scope := c.topmostScope(pkg.Pkg.Scope().Innermost(obj.Pos()), pkg.Pkg) + if scope == pkg.Pkg.Scope() { + c.graph.roots = append(c.graph.roots, node) + } else { + c.graph.markUsedBy(obj, scope) + } + } else { + // Variables declared in functions are used. This is + // done so that arguments and return parameters are + // always marked as used. + if _, ok := obj.(*types.Var); ok { + if obj.Parent() != obj.Pkg().Scope() && obj.Parent() != nil { + c.graph.markUsedBy(obj, c.topmostScope(obj.Parent(), obj.Pkg())) + c.graph.markUsedBy(obj.Type(), obj) + } + } + } + } + + if fn, ok := obj.(*types.Func); ok { + // A function uses its signature + c.graph.markUsedBy(fn, fn.Type()) + + // A function uses its return types + sig := fn.Type().(*types.Signature) + res := sig.Results() + n := res.Len() + for i := 0; i < n; i++ { + c.graph.markUsedBy(res.At(i).Type(), fn) + } + } + + if obj, ok := obj.(interface { + Scope() *types.Scope + Pkg() *types.Package + }); ok { + scope := obj.Scope() + c.graph.markUsedBy(c.topmostScope(scope, obj.Pkg()), obj) + } + + if c.isRoot(obj) { + node := c.graph.getNode(obj) + c.graph.roots = append(c.graph.roots, node) + if obj, ok := obj.(*types.PkgName); ok { + scope := obj.Pkg().Scope() + c.graph.markUsedBy(scope, obj) + } + } + } +} + +func (c *Checker) processUses(pkg *loader.PackageInfo) { + for ident, usedObj := range pkg.Uses { + if _, ok := usedObj.(*types.PkgName); ok { + continue + } + pos := ident.Pos() + scope := pkg.Pkg.Scope().Innermost(pos) + scope = c.topmostScope(scope, pkg.Pkg) + if scope != pkg.Pkg.Scope() { + c.graph.markUsedBy(usedObj, scope) + } + + switch usedObj.(type) { + case *types.Var, *types.Const: + c.graph.markUsedBy(usedObj.Type(), usedObj) + } + } +} + +func (c *Checker) findExportedInterfaces() { + c.interfaces = []*types.Interface{types.Universe.Lookup("error").Type().(*types.Named).Underlying().(*types.Interface)} + var pkgs []*loader.PackageInfo + if c.WholeProgram { + for _, pkg := range c.lprog.AllPackages { + pkgs = append(pkgs, pkg) + } + } else { + pkgs = c.lprog.InitialPackages() + } + + for _, pkg := range pkgs { + for _, tv := range pkg.Types { + iface, ok := tv.Type.(*types.Interface) + if !ok { + continue + } + if iface.NumMethods() == 0 { + continue + } + c.interfaces = append(c.interfaces, iface) + } + } +} + +func (c *Checker) processTypes(pkg *loader.PackageInfo) { + named := map[*types.Named]*types.Pointer{} + var interfaces []*types.Interface + for _, tv := range pkg.Types { + if typ, ok := tv.Type.(interface { + Elem() types.Type + }); ok { + c.graph.markUsedBy(typ.Elem(), typ) + } + + switch obj := tv.Type.(type) { + case *types.Named: + named[obj] = types.NewPointer(obj) + c.graph.markUsedBy(obj, obj.Underlying()) + c.graph.markUsedBy(obj.Underlying(), obj) + case *types.Interface: + if obj.NumMethods() > 0 { + interfaces = append(interfaces, obj) + } + case *types.Struct: + c.useNoCopyFields(obj) + if pkg.Pkg.Name() != "main" && !c.WholeProgram { + c.useExportedFields(obj) + } + } + } + + // Pretend that all types are meant to implement as many + // interfaces as possible. + // + // TODO(dh): For normal operations, that's the best we can do, as + // we have no idea what external users will do with our types. In + // whole-program mode, we could be more conservative, in two ways: + // 1) Only consider interfaces if a type has been assigned to one + // 2) Use SSA and flow analysis and determine the exact set of + // interfaces that is relevant. + fn := func(iface *types.Interface) { + for obj, objPtr := range named { + if !types.Implements(obj, iface) && !types.Implements(objPtr, iface) { + continue + } + ifaceMethods := make(map[string]struct{}, iface.NumMethods()) + n := iface.NumMethods() + for i := 0; i < n; i++ { + meth := iface.Method(i) + ifaceMethods[meth.Name()] = struct{}{} + } + for _, obj := range []types.Type{obj, objPtr} { + ms := c.msCache.MethodSet(obj) + n := ms.Len() + for i := 0; i < n; i++ { + sel := ms.At(i) + meth := sel.Obj().(*types.Func) + _, found := ifaceMethods[meth.Name()] + if !found { + continue + } + c.graph.markUsedBy(meth.Type().(*types.Signature).Recv().Type(), obj) // embedded receiver + if len(sel.Index()) > 1 { + f := getField(obj, sel.Index()[0]) + c.graph.markUsedBy(f, obj) // embedded receiver + } + c.graph.markUsedBy(meth, obj) + } + } + } + } + + for _, iface := range interfaces { + fn(iface) + } + for _, iface := range c.interfaces { + fn(iface) + } +} + +func (c *Checker) processSelections(pkg *loader.PackageInfo) { + fn := func(expr *ast.SelectorExpr, sel *types.Selection, offset int) { + scope := pkg.Pkg.Scope().Innermost(expr.Pos()) + c.graph.markUsedBy(expr.X, c.topmostScope(scope, pkg.Pkg)) + c.graph.markUsedBy(sel.Obj(), expr.X) + if len(sel.Index()) > 1 { + typ := sel.Recv() + indices := sel.Index() + for _, idx := range indices[:len(indices)-offset] { + obj := getField(typ, idx) + typ = obj.Type() + c.graph.markUsedBy(obj, expr.X) + } + } + } + + for expr, sel := range pkg.Selections { + switch sel.Kind() { + case types.FieldVal: + fn(expr, sel, 0) + case types.MethodVal: + fn(expr, sel, 1) + } + } +} + +func dereferenceType(typ types.Type) types.Type { + if typ, ok := typ.(*types.Pointer); ok { + return typ.Elem() + } + return typ +} + +// processConversion marks fields as used if they're part of a type conversion. +func (c *Checker) processConversion(pkg *loader.PackageInfo, node ast.Node) { + if node, ok := node.(*ast.CallExpr); ok { + callTyp := pkg.TypeOf(node.Fun) + var typDst *types.Struct + var ok bool + switch typ := callTyp.(type) { + case *types.Named: + typDst, ok = typ.Underlying().(*types.Struct) + case *types.Pointer: + typDst, ok = typ.Elem().Underlying().(*types.Struct) + default: + return + } + if !ok { + return + } + + if typ, ok := pkg.TypeOf(node.Args[0]).(*types.Basic); ok && typ.Kind() == types.UnsafePointer { + // This is an unsafe conversion. Assume that all the + // fields are relevant (they are, because of memory + // layout) + n := typDst.NumFields() + for i := 0; i < n; i++ { + c.graph.markUsedBy(typDst.Field(i), typDst) + } + return + } + + typSrc, ok := dereferenceType(pkg.TypeOf(node.Args[0])).Underlying().(*types.Struct) + if !ok { + return + } + + // When we convert from type t1 to t2, were t1 and t2 are + // structs, all fields are relevant, as otherwise the + // conversion would fail. + // + // We mark t2's fields as used by t1's fields, and vice + // versa. That way, if no code actually refers to a field + // in either type, it's still correctly marked as unused. + // If a field is used in either struct, it's implicitly + // relevant in the other one, too. + // + // It works in a similar way for conversions between types + // of two packages, only that the extra information in the + // graph is redundant unless we're in whole program mode. + n := typDst.NumFields() + for i := 0; i < n; i++ { + fDst := typDst.Field(i) + fSrc := typSrc.Field(i) + c.graph.markUsedBy(fDst, fSrc) + c.graph.markUsedBy(fSrc, fDst) + } + } +} + +// processCompositeLiteral marks fields as used if the struct is used +// in a composite literal. +func (c *Checker) processCompositeLiteral(pkg *loader.PackageInfo, node ast.Node) { + // XXX how does this actually work? wouldn't it match t{}? + if node, ok := node.(*ast.CompositeLit); ok { + typ := pkg.TypeOf(node) + if _, ok := typ.(*types.Named); ok { + typ = typ.Underlying() + } + if _, ok := typ.(*types.Struct); !ok { + return + } + + if isBasicStruct(node.Elts) { + c.markFields(typ) + } + } +} + +// processCgoExported marks functions as used if they're being +// exported to cgo. +func (c *Checker) processCgoExported(pkg *loader.PackageInfo, node ast.Node) { + if node, ok := node.(*ast.FuncDecl); ok { + if node.Doc == nil { + return + } + for _, cmt := range node.Doc.List { + if !strings.HasPrefix(cmt.Text, "//go:cgo_export_") { + return + } + obj := pkg.ObjectOf(node.Name) + c.graph.roots = append(c.graph.roots, c.graph.getNode(obj)) + } + } +} + +func (c *Checker) processVariableDeclaration(pkg *loader.PackageInfo, node ast.Node) { + if decl, ok := node.(*ast.GenDecl); ok { + for _, spec := range decl.Specs { + spec, ok := spec.(*ast.ValueSpec) + if !ok { + continue + } + for i, name := range spec.Names { + if i >= len(spec.Values) { + break + } + value := spec.Values[i] + fn := func(node ast.Node) bool { + if node3, ok := node.(*ast.Ident); ok { + obj := pkg.ObjectOf(node3) + if _, ok := obj.(*types.PkgName); ok { + return true + } + c.graph.markUsedBy(obj, pkg.ObjectOf(name)) + } + return true + } + ast.Inspect(value, fn) + } + } + } +} + +func (c *Checker) processArrayConstants(pkg *loader.PackageInfo, node ast.Node) { + if decl, ok := node.(*ast.ArrayType); ok { + ident, ok := decl.Len.(*ast.Ident) + if !ok { + return + } + c.graph.markUsedBy(pkg.ObjectOf(ident), pkg.TypeOf(decl)) + } +} + +func (c *Checker) processKnownReflectMethodCallers(pkg *loader.PackageInfo, node ast.Node) { + call, ok := node.(*ast.CallExpr) + if !ok { + return + } + sel, ok := call.Fun.(*ast.SelectorExpr) + if !ok { + return + } + if types.TypeString(pkg.TypeOf(sel.X), nil) != "*net/rpc.Server" { + x, ok := sel.X.(*ast.Ident) + if !ok { + return + } + pkgname, ok := pkg.ObjectOf(x).(*types.PkgName) + if !ok { + return + } + if pkgname.Imported().Path() != "net/rpc" { + return + } + } + + var arg ast.Expr + switch sel.Sel.Name { + case "Register": + if len(call.Args) != 1 { + return + } + arg = call.Args[0] + case "RegisterName": + if len(call.Args) != 2 { + return + } + arg = call.Args[1] + } + typ := pkg.TypeOf(arg) + ms := types.NewMethodSet(typ) + for i := 0; i < ms.Len(); i++ { + c.graph.markUsedBy(ms.At(i).Obj(), typ) + } +} + +func (c *Checker) processAST(pkg *loader.PackageInfo) { + fn := func(node ast.Node) bool { + c.processConversion(pkg, node) + c.processKnownReflectMethodCallers(pkg, node) + c.processCompositeLiteral(pkg, node) + c.processCgoExported(pkg, node) + c.processVariableDeclaration(pkg, node) + c.processArrayConstants(pkg, node) + return true + } + for _, file := range pkg.Files { + ast.Inspect(file, fn) + } +} + +func isBasicStruct(elts []ast.Expr) bool { + for _, elt := range elts { + if _, ok := elt.(*ast.KeyValueExpr); !ok { + return true + } + } + return false +} + +func isPkgScope(obj types.Object) bool { + return obj.Parent() == obj.Pkg().Scope() +} + +func isMain(obj types.Object) bool { + if obj.Pkg().Name() != "main" { + return false + } + if obj.Name() != "main" { + return false + } + if !isPkgScope(obj) { + return false + } + if !isFunction(obj) { + return false + } + if isMethod(obj) { + return false + } + return true +} + +func isFunction(obj types.Object) bool { + _, ok := obj.(*types.Func) + return ok +} + +func isMethod(obj types.Object) bool { + if !isFunction(obj) { + return false + } + return obj.(*types.Func).Type().(*types.Signature).Recv() != nil +} + +func isVariable(obj types.Object) bool { + _, ok := obj.(*types.Var) + return ok +} + +func isConstant(obj types.Object) bool { + _, ok := obj.(*types.Const) + return ok +} + +func isType(obj types.Object) bool { + _, ok := obj.(*types.TypeName) + return ok +} + +func isField(obj types.Object) bool { + if obj, ok := obj.(*types.Var); ok && obj.IsField() { + return true + } + return false +} + +func (c *Checker) checkFlags(v interface{}) bool { + obj, ok := v.(types.Object) + if !ok { + return false + } + if isFunction(obj) && !c.checkFunctions() { + return false + } + if isVariable(obj) && !c.checkVariables() { + return false + } + if isConstant(obj) && !c.checkConstants() { + return false + } + if isType(obj) && !c.checkTypes() { + return false + } + if isField(obj) && !c.checkFields() { + return false + } + return true +} + +func (c *Checker) isRoot(obj types.Object) bool { + // - in local mode, main, init, tests, and non-test, non-main exported are roots + // - in global mode (not yet implemented), main, init and tests are roots + + if _, ok := obj.(*types.PkgName); ok { + return true + } + + if isMain(obj) || (isFunction(obj) && !isMethod(obj) && obj.Name() == "init") { + return true + } + if obj.Exported() { + f := c.lprog.Fset.Position(obj.Pos()).Filename + if strings.HasSuffix(f, "_test.go") { + return strings.HasPrefix(obj.Name(), "Test") || + strings.HasPrefix(obj.Name(), "Benchmark") || + strings.HasPrefix(obj.Name(), "Example") + } + + // Package-level are used, except in package main + if isPkgScope(obj) && obj.Pkg().Name() != "main" && !c.WholeProgram { + return true + } + } + return false +} + +func markNodesUsed(nodes map[*graphNode]struct{}) { + for node := range nodes { + wasUsed := node.used + node.used = true + if !wasUsed { + markNodesUsed(node.uses) + } + } +} + +func (c *Checker) markNodesQuiet() { + for _, node := range c.graph.nodes { + if node.used { + continue + } + if obj, ok := node.obj.(types.Object); ok && !c.checkFlags(obj) { + node.quiet = true + continue + } + c.markObjQuiet(node.obj) + } +} + +func (c *Checker) markObjQuiet(obj interface{}) { + switch obj := obj.(type) { + case *types.Named: + n := obj.NumMethods() + for i := 0; i < n; i++ { + meth := obj.Method(i) + node := c.graph.getNode(meth) + node.quiet = true + c.markObjQuiet(meth.Scope()) + } + case *types.Struct: + n := obj.NumFields() + for i := 0; i < n; i++ { + field := obj.Field(i) + c.graph.nodes[field].quiet = true + } + case *types.Func: + c.markObjQuiet(obj.Scope()) + case *types.Scope: + if obj == nil { + return + } + if obj.Parent() == types.Universe { + return + } + for _, name := range obj.Names() { + v := obj.Lookup(name) + if n, ok := c.graph.nodes[v]; ok { + n.quiet = true + } + } + n := obj.NumChildren() + for i := 0; i < n; i++ { + c.markObjQuiet(obj.Child(i)) + } + } +} + +func getField(typ types.Type, idx int) *types.Var { + switch obj := typ.(type) { + case *types.Pointer: + return getField(obj.Elem(), idx) + case *types.Named: + switch v := obj.Underlying().(type) { + case *types.Struct: + return v.Field(idx) + case *types.Pointer: + return getField(v.Elem(), idx) + default: + panic(fmt.Sprintf("unexpected type %s", typ)) + } + case *types.Struct: + return obj.Field(idx) + } + return nil +} + +func (c *Checker) topmostScope(scope *types.Scope, pkg *types.Package) (ret *types.Scope) { + if top, ok := c.topmostCache[scope]; ok { + return top + } + defer func() { + c.topmostCache[scope] = ret + }() + if scope == pkg.Scope() { + return scope + } + if scope.Parent().Parent() == pkg.Scope() { + return scope + } + return c.topmostScope(scope.Parent(), pkg) +} + +func (c *Checker) printDebugGraph(w io.Writer) { + fmt.Fprintln(w, "digraph {") + fmt.Fprintln(w, "n0 [label = roots]") + for _, node := range c.graph.nodes { + s := fmt.Sprintf("%s (%T)", node.obj, node.obj) + s = strings.Replace(s, "\n", "", -1) + s = strings.Replace(s, `"`, "", -1) + fmt.Fprintf(w, `n%d [label = %q]`, node.n, s) + color := "black" + switch { + case node.used: + color = "green" + case node.quiet: + color = "orange" + case !c.checkFlags(node.obj): + color = "purple" + default: + color = "red" + } + fmt.Fprintf(w, "[color = %s]", color) + fmt.Fprintln(w) + } + + for _, node1 := range c.graph.nodes { + for node2 := range node1.uses { + fmt.Fprintf(w, "n%d -> n%d\n", node1.n, node2.n) + } + } + for _, root := range c.graph.roots { + fmt.Fprintf(w, "n0 -> n%d\n", root.n) + } + fmt.Fprintln(w, "}") +} + +func isGenerated(comment string) bool { + return strings.Contains(comment, "Code generated by") || + strings.Contains(comment, "DO NOT EDIT") +} diff --git a/vendor/honnef.co/go/tools/version/version.go b/vendor/honnef.co/go/tools/version/version.go new file mode 100644 index 0000000..9536482 --- /dev/null +++ b/vendor/honnef.co/go/tools/version/version.go @@ -0,0 +1,17 @@ +package version + +import ( + "fmt" + "os" + "path/filepath" +) + +const Version = "2017.2.2" + +func Print() { + if Version == "devel" { + fmt.Printf("%s (no version)\n", filepath.Base(os.Args[0])) + } else { + fmt.Printf("%s %s\n", filepath.Base(os.Args[0]), Version) + } +} |