| 1 | // Copyright 2013 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 | // ssadump: a tool for displaying and interpreting the SSA form of Go programs. |
| 6 | package main // import "golang.org/x/tools/cmd/ssadump" |
| 7 | |
| 8 | import ( |
| 9 | "flag" |
| 10 | "fmt" |
| 11 | "go/build" |
| 12 | "go/types" |
| 13 | "os" |
| 14 | "runtime" |
| 15 | "runtime/pprof" |
| 16 | |
| 17 | "golang.org/x/tools/go/buildutil" |
| 18 | "golang.org/x/tools/go/packages" |
| 19 | "golang.org/x/tools/go/ssa" |
| 20 | "golang.org/x/tools/go/ssa/interp" |
| 21 | "golang.org/x/tools/go/ssa/ssautil" |
| 22 | ) |
| 23 | |
| 24 | // flags |
| 25 | var ( |
| 26 | mode = ssa.BuilderMode(0) |
| 27 | |
| 28 | testFlag = flag.Bool("test", false, "include implicit test packages and executables") |
| 29 | |
| 30 | runFlag = flag.Bool("run", false, "interpret the SSA program") |
| 31 | |
| 32 | interpFlag = flag.String("interp", "", `Options controlling the SSA test interpreter. |
| 33 | The value is a sequence of zero or more more of these letters: |
| 34 | R disable [R]ecover() from panic; show interpreter crash instead. |
| 35 | T [T]race execution of the program. Best for single-threaded programs! |
| 36 | `) |
| 37 | |
| 38 | cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file") |
| 39 | |
| 40 | args stringListValue |
| 41 | ) |
| 42 | |
| 43 | func init() { |
| 44 | flag.Var(&mode, "build", ssa.BuilderModeDoc) |
| 45 | flag.Var((*buildutil.TagsFlag)(&build.Default.BuildTags), "tags", buildutil.TagsFlagDoc) |
| 46 | flag.Var(&args, "arg", "add argument to interpreted program") |
| 47 | } |
| 48 | |
| 49 | const usage = `SSA builder and interpreter. |
| 50 | Usage: ssadump [-build=[DBCSNFLG]] [-test] [-run] [-interp=[TR]] [-arg=...] package... |
| 51 | Use -help flag to display options. |
| 52 | |
| 53 | Examples: |
| 54 | % ssadump -build=F hello.go # dump SSA form of a single package |
| 55 | % ssadump -build=F -test fmt # dump SSA form of a package and its tests |
| 56 | % ssadump -run -interp=T hello.go # interpret a program, with tracing |
| 57 | |
| 58 | The -run flag causes ssadump to build the code in a runnable form and run the first |
| 59 | package named main. |
| 60 | |
| 61 | Interpretation of the standard "testing" package is no longer supported. |
| 62 | ` |
| 63 | |
| 64 | func main() { |
| 65 | if err := doMain(); err != nil { |
| 66 | fmt.Fprintf(os.Stderr, "ssadump: %s\n", err) |
| 67 | os.Exit(1) |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | func doMain() error { |
| 72 | flag.Parse() |
| 73 | if len(flag.Args()) == 0 { |
| 74 | fmt.Fprint(os.Stderr, usage) |
| 75 | os.Exit(1) |
| 76 | } |
| 77 | |
| 78 | cfg := &packages.Config{ |
| 79 | Mode: packages.LoadSyntax, |
| 80 | Tests: *testFlag, |
| 81 | } |
| 82 | |
| 83 | // Choose types.Sizes from conf.Build. |
| 84 | // TODO(adonovan): remove this when go/packages provides a better way. |
| 85 | var wordSize int64 = 8 |
| 86 | switch build.Default.GOARCH { |
| 87 | case "386", "arm": |
| 88 | wordSize = 4 |
| 89 | } |
| 90 | sizes := &types.StdSizes{ |
| 91 | MaxAlign: 8, |
| 92 | WordSize: wordSize, |
| 93 | } |
| 94 | |
| 95 | var interpMode interp.Mode |
| 96 | for _, c := range *interpFlag { |
| 97 | switch c { |
| 98 | case 'T': |
| 99 | interpMode |= interp.EnableTracing |
| 100 | case 'R': |
| 101 | interpMode |= interp.DisableRecover |
| 102 | default: |
| 103 | return fmt.Errorf("unknown -interp option: '%c'", c) |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | // Profiling support. |
| 108 | if *cpuprofile != "" { |
| 109 | f, err := os.Create(*cpuprofile) |
| 110 | if err != nil { |
| 111 | fmt.Fprintln(os.Stderr, err) |
| 112 | os.Exit(1) |
| 113 | } |
| 114 | pprof.StartCPUProfile(f) |
| 115 | defer pprof.StopCPUProfile() |
| 116 | } |
| 117 | |
| 118 | // Load, parse and type-check the initial packages, |
| 119 | // and, if -run, their dependencies. |
| 120 | if *runFlag { |
| 121 | cfg.Mode = packages.LoadAllSyntax |
| 122 | } |
| 123 | initial, err := packages.Load(cfg, flag.Args()...) |
| 124 | if err != nil { |
| 125 | return err |
| 126 | } |
| 127 | if len(initial) == 0 { |
| 128 | return fmt.Errorf("no packages") |
| 129 | } |
| 130 | if packages.PrintErrors(initial) > 0 { |
| 131 | return fmt.Errorf("packages contain errors") |
| 132 | } |
| 133 | |
| 134 | // Turn on instantiating generics during build if the program will be run. |
| 135 | if *runFlag { |
| 136 | mode |= ssa.InstantiateGenerics |
| 137 | } |
| 138 | |
| 139 | // Create SSA-form program representation. |
| 140 | prog, pkgs := ssautil.AllPackages(initial, mode) |
| 141 | |
| 142 | for i, p := range pkgs { |
| 143 | if p == nil { |
| 144 | return fmt.Errorf("cannot build SSA for package %s", initial[i]) |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | if !*runFlag { |
| 149 | // Build and display only the initial packages |
| 150 | // (and synthetic wrappers). |
| 151 | for _, p := range pkgs { |
| 152 | p.Build() |
| 153 | } |
| 154 | |
| 155 | } else { |
| 156 | // Run the interpreter. |
| 157 | // Build SSA for all packages. |
| 158 | prog.Build() |
| 159 | |
| 160 | // Earlier versions of the interpreter needed the runtime |
| 161 | // package; however, interp cannot handle unsafe constructs |
| 162 | // used during runtime's package initialization at the moment. |
| 163 | // The key construct blocking support is: |
| 164 | // *((*T)(unsafe.Pointer(p))) |
| 165 | // Unfortunately, this means only trivial programs can be |
| 166 | // interpreted by ssadump. |
| 167 | if prog.ImportedPackage("runtime") != nil { |
| 168 | return fmt.Errorf("-run: program depends on runtime package (interpreter can run only trivial programs)") |
| 169 | } |
| 170 | |
| 171 | if runtime.GOARCH != build.Default.GOARCH { |
| 172 | return fmt.Errorf("cross-interpretation is not supported (target has GOARCH %s, interpreter has %s)", |
| 173 | build.Default.GOARCH, runtime.GOARCH) |
| 174 | } |
| 175 | |
| 176 | // Run first main package. |
| 177 | for _, main := range ssautil.MainPackages(pkgs) { |
| 178 | fmt.Fprintf(os.Stderr, "Running: %s\n", main.Pkg.Path()) |
| 179 | os.Exit(interp.Interpret(main, interpMode, sizes, main.Pkg.Path(), args)) |
| 180 | } |
| 181 | return fmt.Errorf("no main package") |
| 182 | } |
| 183 | return nil |
| 184 | } |
| 185 | |
| 186 | // stringListValue is a flag.Value that accumulates strings. |
| 187 | // e.g. --flag=one --flag=two would produce []string{"one", "two"}. |
| 188 | type stringListValue []string |
| 189 | |
| 190 | func newStringListValue(val []string, p *[]string) *stringListValue { |
| 191 | *p = val |
| 192 | return (*stringListValue)(p) |
| 193 | } |
| 194 | |
| 195 | func (ss *stringListValue) Get() interface{} { return []string(*ss) } |
| 196 | |
| 197 | func (ss *stringListValue) String() string { return fmt.Sprintf("%q", *ss) } |
| 198 | |
| 199 | func (ss *stringListValue) Set(s string) error { *ss = append(*ss, s); return nil } |
| 200 |
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