| 1 | // Copyright 2021 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package vta |
| 6 | |
| 7 | import ( |
| 8 | "fmt" |
| 9 | "go/ast" |
| 10 | "go/parser" |
| 11 | "io/ioutil" |
| 12 | "sort" |
| 13 | "strings" |
| 14 | |
| 15 | "golang.org/x/tools/go/callgraph" |
| 16 | "golang.org/x/tools/go/ssa/ssautil" |
| 17 | |
| 18 | "golang.org/x/tools/go/loader" |
| 19 | "golang.org/x/tools/go/ssa" |
| 20 | ) |
| 21 | |
| 22 | // want extracts the contents of the first comment |
| 23 | // section starting with "WANT:\n". The returned |
| 24 | // content is split into lines without // prefix. |
| 25 | func want(f *ast.File) []string { |
| 26 | for _, c := range f.Comments { |
| 27 | text := strings.TrimSpace(c.Text()) |
| 28 | if t := strings.TrimPrefix(text, "WANT:\n"); t != text { |
| 29 | return strings.Split(t, "\n") |
| 30 | } |
| 31 | } |
| 32 | return nil |
| 33 | } |
| 34 | |
| 35 | // testProg returns an ssa representation of a program at |
| 36 | // `path`, assumed to define package "testdata," and the |
| 37 | // test want result as list of strings. |
| 38 | func testProg(path string, mode ssa.BuilderMode) (*ssa.Program, []string, error) { |
| 39 | content, err := ioutil.ReadFile(path) |
| 40 | if err != nil { |
| 41 | return nil, nil, err |
| 42 | } |
| 43 | |
| 44 | conf := loader.Config{ |
| 45 | ParserMode: parser.ParseComments, |
| 46 | } |
| 47 | |
| 48 | f, err := conf.ParseFile(path, content) |
| 49 | if err != nil { |
| 50 | return nil, nil, err |
| 51 | } |
| 52 | |
| 53 | conf.CreateFromFiles("testdata", f) |
| 54 | iprog, err := conf.Load() |
| 55 | if err != nil { |
| 56 | return nil, nil, err |
| 57 | } |
| 58 | |
| 59 | prog := ssautil.CreateProgram(iprog, mode) |
| 60 | // Set debug mode to exercise DebugRef instructions. |
| 61 | prog.Package(iprog.Created[0].Pkg).SetDebugMode(true) |
| 62 | prog.Build() |
| 63 | return prog, want(f), nil |
| 64 | } |
| 65 | |
| 66 | func firstRegInstr(f *ssa.Function) ssa.Value { |
| 67 | for _, b := range f.Blocks { |
| 68 | for _, i := range b.Instrs { |
| 69 | if v, ok := i.(ssa.Value); ok { |
| 70 | return v |
| 71 | } |
| 72 | } |
| 73 | } |
| 74 | return nil |
| 75 | } |
| 76 | |
| 77 | // funcName returns a name of the function `f` |
| 78 | // prefixed with the name of the receiver type. |
| 79 | func funcName(f *ssa.Function) string { |
| 80 | recv := f.Signature.Recv() |
| 81 | if recv == nil { |
| 82 | return f.Name() |
| 83 | } |
| 84 | tp := recv.Type().String() |
| 85 | return tp[strings.LastIndex(tp, ".")+1:] + "." + f.Name() |
| 86 | } |
| 87 | |
| 88 | // callGraphStr stringifes `g` into a list of strings where |
| 89 | // each entry is of the form |
| 90 | // |
| 91 | // f: cs1 -> f1, f2, ...; ...; csw -> fx, fy, ... |
| 92 | // |
| 93 | // f is a function, cs1, ..., csw are call sites in f, and |
| 94 | // f1, f2, ..., fx, fy, ... are the resolved callees. |
| 95 | func callGraphStr(g *callgraph.Graph) []string { |
| 96 | var gs []string |
| 97 | for f, n := range g.Nodes { |
| 98 | c := make(map[string][]string) |
| 99 | for _, edge := range n.Out { |
| 100 | cs := edge.Site.String() |
| 101 | c[cs] = append(c[cs], funcName(edge.Callee.Func)) |
| 102 | } |
| 103 | |
| 104 | var cs []string |
| 105 | for site, fs := range c { |
| 106 | sort.Strings(fs) |
| 107 | entry := fmt.Sprintf("%v -> %v", site, strings.Join(fs, ", ")) |
| 108 | cs = append(cs, entry) |
| 109 | } |
| 110 | |
| 111 | sort.Strings(cs) |
| 112 | entry := fmt.Sprintf("%v: %v", funcName(f), strings.Join(cs, "; ")) |
| 113 | gs = append(gs, entry) |
| 114 | } |
| 115 | return gs |
| 116 | } |
| 117 |
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