src/cmd/dist/buildtool.go

   1 // Copyright 2015 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 // Build toolchain using Go 1.4.
   6 //
   7 // The general strategy is to copy the source files we need into
   8 // a new GOPATH workspace, adjust import paths appropriately,
   9 // invoke the Go 1.4 go command to build those sources,
  10 // and then copy the binaries back.
  11
  12 package main
  13
  14 import (
  15         "fmt"
  16         "os"
  17         "path/filepath"
  18         "runtime"
  19         "strings"
  20 )
  21
  22 // bootstrapDirs is a list of directories holding code that must be
  23 // compiled with a Go 1.4 toolchain to produce the bootstrapTargets.
  24 // All directories in this list are relative to and must be below $GOROOT/src.
  25 //
  26 // The list has two kinds of entries: names beginning with cmd/ with
  27 // no other slashes, which are commands, and other paths, which are packages
  28 // supporting the commands. Packages in the standard library can be listed
  29 // if a newer copy needs to be substituted for the Go 1.4 copy when used
  30 // by the command packages. Paths ending with /... automatically
  31 // include all packages within subdirectories as well.
  32 // These will be imported during bootstrap as bootstrap/name, like bootstrap/math/big.
  33 var bootstrapDirs = []string{
  34         "cmd/asm",
  35         "cmd/asm/internal/...",
  36         "cmd/compile",
  37         "cmd/compile/internal/...",
  38         "cmd/internal/archive",
  39         "cmd/internal/bio",
  40         "cmd/internal/codesign",
  41         "cmd/internal/dwarf",
  42         "cmd/internal/edit",
  43         "cmd/internal/gcprog",
  44         "cmd/internal/goobj",
  45         "cmd/internal/obj/...",
  46         "cmd/internal/objabi",
  47         "cmd/internal/pkgpath",
  48         "cmd/internal/src",
  49         "cmd/internal/str",
  50         "cmd/internal/sys",
  51         "cmd/link",
  52         "cmd/link/internal/...",
  53         "compress/flate",
  54         "compress/zlib",
  55         "container/heap",
  56         "debug/dwarf",
  57         "debug/elf",
  58         "debug/macho",
  59         "debug/pe",
  60         "go/constant",
  61         "internal/buildcfg",
  62         "internal/goexperiment",
  63         "internal/goversion",
  64         "internal/race",
  65         "internal/unsafeheader",
  66         "internal/xcoff",
  67         "math/big",
  68         "math/bits",
  69         "sort",
  70         "strconv",
  71 }
  72
  73 // File prefixes that are ignored by go/build anyway, and cause
  74 // problems with editor generated temporary files (#18931).
  75 var ignorePrefixes = []string{
  76         ".",
  77         "_",
  78         "#",
  79 }
  80
  81 // File suffixes that use build tags introduced since Go 1.4.
  82 // These must not be copied into the bootstrap build directory.
  83 // Also ignore test files.
  84 var ignoreSuffixes = []string{
  85         "_arm64.s",
  86         "_arm64.go",
  87         "_riscv64.s",
  88         "_riscv64.go",
  89         "_wasm.s",
  90         "_wasm.go",
  91         "_test.s",
  92         "_test.go",
  93 }
  94
  95 func bootstrapBuildTools() {
  96         goroot_bootstrap := os.Getenv("GOROOT_BOOTSTRAP")
  97         if goroot_bootstrap == "" {
  98                 goroot_bootstrap = pathf("%s/go1.4", os.Getenv("HOME"))
  99         }
 100         xprintf("Building Go toolchain1 using %s.\n", goroot_bootstrap)
 101
 102         mkbuildcfg(pathf("%s/src/internal/buildcfg/zbootstrap.go", goroot))
 103         mkobjabi(pathf("%s/src/cmd/internal/objabi/zbootstrap.go", goroot))
 104         mkzdefaultcc("", pathf("%s/src/cmd/cgo/zdefaultcc.go", goroot))
 105
 106         // Use $GOROOT/pkg/bootstrap as the bootstrap workspace root.
 107         // We use a subdirectory of $GOROOT/pkg because that's the
 108         // space within $GOROOT where we store all generated objects.
 109         // We could use a temporary directory outside $GOROOT instead,
 110         // but it is easier to debug on failure if the files are in a known location.
 111         workspace := pathf("%s/pkg/bootstrap", goroot)
 112         xremoveall(workspace)
 113         xatexit(func() { xremoveall(workspace) })
 114         base := pathf("%s/src/bootstrap", workspace)
 115         xmkdirall(base)
 116
 117         // Copy source code into $GOROOT/pkg/bootstrap and rewrite import paths.
 118         writefile("module bootstrap\n", pathf("%s/%s", base, "go.mod"), 0)
 119         for _, dir := range bootstrapDirs {
 120                 recurse := strings.HasSuffix(dir, "/...")
 121                 dir = strings.TrimSuffix(dir, "/...")
 122                 filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
 123                         if err != nil {
 124                                 fatalf("walking bootstrap dirs failed: %v: %v", path, err)
 125                         }
 126
 127                         name := filepath.Base(path)
 128                         src := pathf("%s/src/%s", goroot, path)
 129                         dst := pathf("%s/%s", base, path)
 130
 131                         if info.IsDir() {
 132                                 if !recurse && path != dir || name == "testdata" {
 133                                         return filepath.SkipDir
 134                                 }
 135
 136                                 xmkdirall(dst)
 137                                 return nil
 138                         }
 139
 140                         for _, pre := range ignorePrefixes {
 141                                 if strings.HasPrefix(name, pre) {
 142                                         return nil
 143                                 }
 144                         }
 145                         for _, suf := range ignoreSuffixes {
 146                                 if strings.HasSuffix(name, suf) {
 147                                         return nil
 148                                 }
 149                         }
 150
 151                         text := bootstrapRewriteFile(src)
 152                         writefile(text, dst, 0)
 153                         return nil
 154                 })
 155         }
 156
 157         // Set up environment for invoking Go 1.4 go command.
 158         // GOROOT points at Go 1.4 GOROOT,
 159         // GOPATH points at our bootstrap workspace,
 160         // GOBIN is empty, so that binaries are installed to GOPATH/bin,
 161         // and GOOS, GOHOSTOS, GOARCH, and GOHOSTOS are empty,
 162         // so that Go 1.4 builds whatever kind of binary it knows how to build.
 163         // Restore GOROOT, GOPATH, and GOBIN when done.
 164         // Don't bother with GOOS, GOHOSTOS, GOARCH, and GOHOSTARCH,
 165         // because setup will take care of those when bootstrapBuildTools returns.
 166
 167         defer os.Setenv("GOROOT", os.Getenv("GOROOT"))
 168         os.Setenv("GOROOT", goroot_bootstrap)
 169
 170         defer os.Setenv("GOPATH", os.Getenv("GOPATH"))
 171         os.Setenv("GOPATH", workspace)
 172
 173         defer os.Setenv("GOBIN", os.Getenv("GOBIN"))
 174         os.Setenv("GOBIN", "")
 175
 176         os.Setenv("GOOS", "")
 177         os.Setenv("GOHOSTOS", "")
 178         os.Setenv("GOARCH", "")
 179         os.Setenv("GOHOSTARCH", "")
 180
 181         // Run Go 1.4 to build binaries. Use -gcflags=-l to disable inlining to
 182         // workaround bugs in Go 1.4's compiler. See discussion thread:
 183         // https://groups.google.com/d/msg/golang-dev/Ss7mCKsvk8w/Gsq7VYI0AwAJ
 184         // Use the math_big_pure_go build tag to disable the assembly in math/big
 185         // which may contain unsupported instructions.
 186         // Note that if we are using Go 1.10 or later as bootstrap, the -gcflags=-l
 187         // only applies to the final cmd/go binary, but that's OK: if this is Go 1.10
 188         // or later we don't need to disable inlining to work around bugs in the Go 1.4 compiler.
 189         cmd := []string{
 190                 pathf("%s/bin/go", goroot_bootstrap),
 191                 "install",
 192                 "-gcflags=-l",
 193                 "-tags=math_big_pure_go compiler_bootstrap",
 194         }
 195         if vflag > 0 {
 196                 cmd = append(cmd, "-v")
 197         }
 198         if tool := os.Getenv("GOBOOTSTRAP_TOOLEXEC"); tool != "" {
 199                 cmd = append(cmd, "-toolexec="+tool)
 200         }
 201         cmd = append(cmd, "bootstrap/cmd/...")
 202         run(base, ShowOutput|CheckExit, cmd...)
 203
 204         // Copy binaries into tool binary directory.
 205         for _, name := range bootstrapDirs {
 206                 if !strings.HasPrefix(name, "cmd/") {
 207                         continue
 208                 }
 209                 name = name[len("cmd/"):]
 210                 if !strings.Contains(name, "/") {
 211                         copyfile(pathf("%s/%s%s", tooldir, name, exe), pathf("%s/bin/%s%s", workspace, name, exe), writeExec)
 212                 }
 213         }
 214
 215         if vflag > 0 {
 216                 xprintf("\n")
 217         }
 218 }
 219
 220 var ssaRewriteFileSubstring = filepath.FromSlash("src/cmd/compile/internal/ssa/rewrite")
 221
 222 // isUnneededSSARewriteFile reports whether srcFile is a
 223 // src/cmd/compile/internal/ssa/rewriteARCHNAME.go file for an
 224 // architecture that isn't for the current runtime.GOARCH.
 225 //
 226 // When unneeded is true archCaps is the rewrite base filename without
 227 // the "rewrite" prefix or ".go" suffix: AMD64, 386, ARM, ARM64, etc.
 228 func isUnneededSSARewriteFile(srcFile string) (archCaps string, unneeded bool) {
 229         if !strings.Contains(srcFile, ssaRewriteFileSubstring) {
 230                 return "", false
 231         }
 232         fileArch := strings.TrimSuffix(strings.TrimPrefix(filepath.Base(srcFile), "rewrite"), ".go")
 233         if fileArch == "" {
 234                 return "", false
 235         }
 236         b := fileArch[0]
 237         if b == '_' || ('a' <= b && b <= 'z') {
 238                 return "", false
 239         }
 240         archCaps = fileArch
 241         fileArch = strings.ToLower(fileArch)
 242         fileArch = strings.TrimSuffix(fileArch, "splitload")
 243         if fileArch == os.Getenv("GOHOSTARCH") {
 244                 return "", false
 245         }
 246         if fileArch == strings.TrimSuffix(runtime.GOARCH, "le") {
 247                 return "", false
 248         }
 249         if fileArch == strings.TrimSuffix(os.Getenv("GOARCH"), "le") {
 250                 return "", false
 251         }
 252         return archCaps, true
 253 }
 254
 255 func bootstrapRewriteFile(srcFile string) string {
 256         // During bootstrap, generate dummy rewrite files for
 257         // irrelevant architectures. We only need to build a bootstrap
 258         // binary that works for the current runtime.GOARCH.
 259         // This saves 6+ seconds of bootstrap.
 260         if archCaps, ok := isUnneededSSARewriteFile(srcFile); ok {
 261                 return fmt.Sprintf(`// Code generated by go tool dist; DO NOT EDIT.
 262
 263 package ssa
 264
 265 func rewriteValue%s(v *Value) bool { panic("unused during bootstrap") }
 266 func rewriteBlock%s(b *Block) bool { panic("unused during bootstrap") }
 267 `, archCaps, archCaps)
 268         }
 269
 270         return bootstrapFixImports(srcFile)
 271 }
 272
 273 func bootstrapFixImports(srcFile string) string {
 274         lines := strings.SplitAfter(readfile(srcFile), "\n")
 275         inBlock := false
 276         for i, line := range lines {
 277                 if strings.HasPrefix(line, "import (") {
 278                         inBlock = true
 279                         continue
 280                 }
 281                 if inBlock && strings.HasPrefix(line, ")") {
 282                         inBlock = false
 283                         continue
 284                 }
 285                 if strings.HasPrefix(line, `import "`) || strings.HasPrefix(line, `import . "`) ||
 286                         inBlock && (strings.HasPrefix(line, "\t\"") || strings.HasPrefix(line, "\t. \"") || strings.HasPrefix(line, "\texec \"")) {
 287                         line = strings.Replace(line, `"cmd/`, `"bootstrap/cmd/`, -1)
 288                         // During bootstrap, must use plain os/exec.
 289                         line = strings.Replace(line, `exec "internal/execabs"`, `"os/exec"`, -1)
 290                         for _, dir := range bootstrapDirs {
 291                                 if strings.HasPrefix(dir, "cmd/") {
 292                                         continue
 293                                 }
 294                                 line = strings.Replace(line, `"`+dir+`"`, `"bootstrap/`+dir+`"`, -1)
 295                         }
 296                         lines[i] = line
 297                 }
 298         }
 299
 300         lines[0] = "// Code generated by go tool dist; DO NOT EDIT.\n// This is a bootstrap copy of " + srcFile + "\n\n//line " + srcFile + ":1\n" + lines[0]
 301
 302         return strings.Join(lines, "")
 303 }