117 lines
3.2 KiB
Go
117 lines
3.2 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package buildssa defines an Analyzer that constructs the SSA
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// representation of an error-free package and returns the set of all
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// functions within it. It does not report any diagnostics itself but
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// may be used as an input to other analyzers.
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//
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// THIS INTERFACE IS EXPERIMENTAL AND MAY BE SUBJECT TO INCOMPATIBLE CHANGE.
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package buildssa
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import (
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"go/ast"
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"go/types"
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"reflect"
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"golang.org/x/tools/go/analysis"
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"honnef.co/go/tools/ssa"
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)
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var Analyzer = &analysis.Analyzer{
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Name: "buildssa",
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Doc: "build SSA-form IR for later passes",
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Run: run,
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ResultType: reflect.TypeOf(new(SSA)),
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}
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// SSA provides SSA-form intermediate representation for all the
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// non-blank source functions in the current package.
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type SSA struct {
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Pkg *ssa.Package
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SrcFuncs []*ssa.Function
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}
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func run(pass *analysis.Pass) (interface{}, error) {
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// Plundered from ssautil.BuildPackage.
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// We must create a new Program for each Package because the
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// analysis API provides no place to hang a Program shared by
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// all Packages. Consequently, SSA Packages and Functions do not
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// have a canonical representation across an analysis session of
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// multiple packages. This is unlikely to be a problem in
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// practice because the analysis API essentially forces all
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// packages to be analysed independently, so any given call to
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// Analysis.Run on a package will see only SSA objects belonging
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// to a single Program.
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mode := ssa.GlobalDebug
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prog := ssa.NewProgram(pass.Fset, mode)
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// Create SSA packages for all imports.
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// Order is not significant.
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created := make(map[*types.Package]bool)
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var createAll func(pkgs []*types.Package)
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createAll = func(pkgs []*types.Package) {
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for _, p := range pkgs {
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if !created[p] {
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created[p] = true
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prog.CreatePackage(p, nil, nil, true)
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createAll(p.Imports())
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}
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}
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}
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createAll(pass.Pkg.Imports())
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// Create and build the primary package.
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ssapkg := prog.CreatePackage(pass.Pkg, pass.Files, pass.TypesInfo, false)
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ssapkg.Build()
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// Compute list of source functions, including literals,
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// in source order.
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var funcs []*ssa.Function
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var addAnons func(f *ssa.Function)
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addAnons = func(f *ssa.Function) {
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funcs = append(funcs, f)
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for _, anon := range f.AnonFuncs {
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addAnons(anon)
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}
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}
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addAnons(ssapkg.Members["init"].(*ssa.Function))
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for _, f := range pass.Files {
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for _, decl := range f.Decls {
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if fdecl, ok := decl.(*ast.FuncDecl); ok {
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// SSA will not build a Function
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// for a FuncDecl named blank.
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// That's arguably too strict but
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// relaxing it would break uniqueness of
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// names of package members.
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if fdecl.Name.Name == "_" {
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continue
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}
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// (init functions have distinct Func
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// objects named "init" and distinct
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// ssa.Functions named "init#1", ...)
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fn := pass.TypesInfo.Defs[fdecl.Name].(*types.Func)
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if fn == nil {
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panic(fn)
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}
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f := ssapkg.Prog.FuncValue(fn)
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if f == nil {
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panic(fn)
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}
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addAnons(f)
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}
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}
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}
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return &SSA{Pkg: ssapkg, SrcFuncs: funcs}, nil
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}
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