// 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 toolchain using Go bootstrap version.
//
// The general strategy is to copy the source files we need into
// a new GOPATH workspace, adjust import paths appropriately,
// invoke the Go bootstrap toolchains go command to build those sources,
// and then copy the binaries back.
package main
import (
"fmt"
"go/version"
"os"
"path/filepath"
"regexp"
"strings"
)
// bootstrapDirs is a list of directories holding code that must be
// compiled with the Go bootstrap toolchain to produce the bootstrapTargets.
// All directories in this list are relative to and must be below $GOROOT/src.
//
// The list has two kinds of entries: names beginning with cmd/ with
// no other slashes, which are commands, and other paths, which are packages
// supporting the commands. Packages in the standard library can be listed
// if a newer copy needs to be substituted for the Go bootstrap copy when used
// by the command packages. Paths ending with /... automatically
// include all packages within subdirectories as well.
// These will be imported during bootstrap as bootstrap/name, like bootstrap/math/big.
var bootstrapDirs = []string{
"cmp",
"cmd/asm",
"cmd/asm/internal/...",
"cmd/cgo",
"cmd/compile",
"cmd/compile/internal/...",
"cmd/internal/archive",
"cmd/internal/bio",
"cmd/internal/codesign",
"cmd/internal/dwarf",
"cmd/internal/edit",
"cmd/internal/gcprog",
"cmd/internal/goobj",
"cmd/internal/hash",
"cmd/internal/macho",
"cmd/internal/obj/...",
"cmd/internal/objabi",
"cmd/internal/pgo",
"cmd/internal/pkgpath",
"cmd/internal/quoted",
"cmd/internal/src",
"cmd/internal/sys",
"cmd/internal/telemetry",
"cmd/internal/telemetry/counter",
"cmd/link",
"cmd/link/internal/...",
"compress/flate",
"compress/zlib",
"container/heap",
"debug/dwarf",
"debug/elf",
"debug/macho",
"debug/pe",
"go/build/constraint",
"go/constant",
"go/version",
"internal/abi",
"internal/coverage",
"cmd/internal/cov/covcmd",
"internal/bisect",
"internal/buildcfg",
"internal/exportdata",
"internal/goarch",
"internal/godebugs",
"internal/goexperiment",
"internal/goroot",
"internal/gover",
"internal/goversion",
// internal/lazyregexp is provided by Go 1.17, which permits it to
// be imported by other packages in this list, but is not provided
// by the Go 1.17 version of gccgo. It's on this list only to
// support gccgo, and can be removed if we require gccgo 14 or later.
"internal/lazyregexp",
"internal/pkgbits",
"internal/platform",
"internal/profile",
"internal/race",
"internal/saferio",
"internal/syscall/unix",
"internal/types/errors",
"internal/unsafeheader",
"internal/xcoff",
"internal/zstd",
"math/bits",
"sort",
}
// File prefixes that are ignored by go/build anyway, and cause
// problems with editor generated temporary files (#18931).
var ignorePrefixes = []string{
".",
"_",
"#",
}
// File suffixes that use build tags introduced since Go 1.17.
// These must not be copied into the bootstrap build directory.
// Also ignore test files.
var ignoreSuffixes = []string{
"_test.s",
"_test.go",
// Skip PGO profile. No need to build toolchain1 compiler
// with PGO. And as it is not a text file the import path
// rewrite will break it.
".pgo",
// Skip editor backup files.
"~",
}
const minBootstrap = "go1.22.6"
var tryDirs = []string{
"sdk/" + minBootstrap,
minBootstrap,
}
func bootstrapBuildTools() {
goroot_bootstrap := os.Getenv("GOROOT_BOOTSTRAP")
if goroot_bootstrap == "" {
home := os.Getenv("HOME")
goroot_bootstrap = pathf("%s/go1.4", home)
for _, d := range tryDirs {
if p := pathf("%s/%s", home, d); isdir(p) {
goroot_bootstrap = p
}
}
}
// check bootstrap version.
ver := run(pathf("%s/bin", goroot_bootstrap), CheckExit, pathf("%s/bin/go", goroot_bootstrap), "env", "GOVERSION")
// go env GOVERSION output like "go1.22.6\n" or "devel go1.24-ffb3e574 Thu Aug 29 20:16:26 2024 +0000\n".
ver = ver[:len(ver)-1]
if version.Compare(ver, version.Lang(minBootstrap)) > 0 && version.Compare(ver, minBootstrap) < 0 {
fatalf("%s does not meet the minimum bootstrap requirement of %s or later", ver, minBootstrap)
}
xprintf("Building Go toolchain1 using %s.\n", goroot_bootstrap)
mkbuildcfg(pathf("%s/src/internal/buildcfg/zbootstrap.go", goroot))
mkobjabi(pathf("%s/src/cmd/internal/objabi/zbootstrap.go", goroot))
// Use $GOROOT/pkg/bootstrap as the bootstrap workspace root.
// We use a subdirectory of $GOROOT/pkg because that's the
// space within $GOROOT where we store all generated objects.
// We could use a temporary directory outside $GOROOT instead,
// but it is easier to debug on failure if the files are in a known location.
workspace := pathf("%s/pkg/bootstrap", goroot)
xremoveall(workspace)
xatexit(func() { xremoveall(workspace) })
base := pathf("%s/src/bootstrap", workspace)
xmkdirall(base)
// Copy source code into $GOROOT/pkg/bootstrap and rewrite import paths.
minBootstrapVers := requiredBootstrapVersion(goModVersion()) // require the minimum required go version to build this go version in the go.mod file
writefile("module bootstrap\ngo "+minBootstrapVers+"\n", pathf("%s/%s", base, "go.mod"), 0)
for _, dir := range bootstrapDirs {
recurse := strings.HasSuffix(dir, "/...")
dir = strings.TrimSuffix(dir, "/...")
filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
if err != nil {
fatalf("walking bootstrap dirs failed: %v: %v", path, err)
}
name := filepath.Base(path)
src := pathf("%s/src/%s", goroot, path)
dst := pathf("%s/%s", base, path)
if info.IsDir() {
if !recurse && path != dir || name == "testdata" {
return filepath.SkipDir
}
xmkdirall(dst)
if path == "cmd/cgo" {
// Write to src because we need the file both for bootstrap
// and for later in the main build.
mkzdefaultcc("", pathf("%s/zdefaultcc.go", src))
mkzdefaultcc("", pathf("%s/zdefaultcc.go", dst))
}
return nil
}
for _, pre := range ignorePrefixes {
if strings.HasPrefix(name, pre) {
return nil
}
}
for _, suf := range ignoreSuffixes {
if strings.HasSuffix(name, suf) {
return nil
}
}
text := bootstrapRewriteFile(src)
writefile(text, dst, 0)
return nil
})
}
// Set up environment for invoking Go bootstrap toolchains go command.
// GOROOT points at Go bootstrap GOROOT,
// GOPATH points at our bootstrap workspace,
// GOBIN is empty, so that binaries are installed to GOPATH/bin,
// and GOOS, GOHOSTOS, GOARCH, and GOHOSTOS are empty,
// so that Go bootstrap toolchain builds whatever kind of binary it knows how to build.
// Restore GOROOT, GOPATH, and GOBIN when done.
// Don't bother with GOOS, GOHOSTOS, GOARCH, and GOHOSTARCH,
// because setup will take care of those when bootstrapBuildTools returns.
defer os.Setenv("GOROOT", os.Getenv("GOROOT"))
os.Setenv("GOROOT", goroot_bootstrap)
defer os.Setenv("GOPATH", os.Getenv("GOPATH"))
os.Setenv("GOPATH", workspace)
defer os.Setenv("GOBIN", os.Getenv("GOBIN"))
os.Setenv("GOBIN", "")
os.Setenv("GOOS", "")
os.Setenv("GOHOSTOS", "")
os.Setenv("GOARCH", "")
os.Setenv("GOHOSTARCH", "")
// Run Go bootstrap to build binaries.
// Use the math_big_pure_go build tag to disable the assembly in math/big
// which may contain unsupported instructions.
// Use the purego build tag to disable other assembly code.
cmd := []string{
pathf("%s/bin/go", goroot_bootstrap),
"install",
"-tags=math_big_pure_go compiler_bootstrap purego",
}
if vflag > 0 {
cmd = append(cmd, "-v")
}
if tool := os.Getenv("GOBOOTSTRAP_TOOLEXEC"); tool != "" {
cmd = append(cmd, "-toolexec="+tool)
}
cmd = append(cmd, "bootstrap/cmd/...")
run(base, ShowOutput|CheckExit, cmd...)
// Copy binaries into tool binary directory.
for _, name := range bootstrapDirs {
if !strings.HasPrefix(name, "cmd/") {
continue
}
name = name[len("cmd/"):]
if !strings.Contains(name, "/") {
copyfile(pathf("%s/%s%s", tooldir, name, exe), pathf("%s/bin/%s%s", workspace, name, exe), writeExec)
}
}
if vflag > 0 {
xprintf("\n")
}
}
var ssaRewriteFileSubstring = filepath.FromSlash("src/cmd/compile/internal/ssa/rewrite")
// isUnneededSSARewriteFile reports whether srcFile is a
// src/cmd/compile/internal/ssa/rewriteARCHNAME.go file for an
// architecture that isn't for the given GOARCH.
//
// When unneeded is true archCaps is the rewrite base filename without
// the "rewrite" prefix or ".go" suffix: AMD64, 386, ARM, ARM64, etc.
func isUnneededSSARewriteFile(srcFile, goArch string) (archCaps string, unneeded bool) {
if !strings.Contains(srcFile, ssaRewriteFileSubstring) {
return "", false
}
fileArch := strings.TrimSuffix(strings.TrimPrefix(filepath.Base(srcFile), "rewrite"), ".go")
if fileArch == "" {
return "", false
}
b := fileArch[0]
if b == '_' || ('a' <= b && b <= 'z') {
return "", false
}
archCaps = fileArch
fileArch = strings.ToLower(fileArch)
fileArch = strings.TrimSuffix(fileArch, "splitload")
fileArch = strings.TrimSuffix(fileArch, "latelower")
if fileArch == goArch {
return "", false
}
if fileArch == strings.TrimSuffix(goArch, "le") {
return "", false
}
return archCaps, true
}
func bootstrapRewriteFile(srcFile string) string {
// During bootstrap, generate dummy rewrite files for
// irrelevant architectures. We only need to build a bootstrap
// binary that works for the current gohostarch.
// This saves 6+ seconds of bootstrap.
if archCaps, ok := isUnneededSSARewriteFile(srcFile, gohostarch); ok {
return fmt.Sprintf(`%spackage ssa
func rewriteValue%s(v *Value) bool { panic("unused during bootstrap") }
func rewriteBlock%s(b *Block) bool { panic("unused during bootstrap") }
`, generatedHeader, archCaps, archCaps)
}
return bootstrapFixImports(srcFile)
}
var (
importRE = regexp.MustCompile(`\Aimport\s+(\.|[A-Za-z0-9_]+)?\s*"([^"]+)"\s*(//.*)?\n\z`)
importBlockRE = regexp.MustCompile(`\A\s*(?:(\.|[A-Za-z0-9_]+)?\s*"([^"]+)")?\s*(//.*)?\n\z`)
)
func bootstrapFixImports(srcFile string) string {
text := readfile(srcFile)
lines := strings.SplitAfter(text, "\n")
inBlock := false
inComment := false
for i, line := range lines {
if strings.HasSuffix(line, "*/\n") {
inComment = false
}
if strings.HasSuffix(line, "/*\n") {
inComment = true
}
if inComment {
continue
}
if strings.HasPrefix(line, "import (") {
inBlock = true
continue
}
if inBlock && strings.HasPrefix(line, ")") {
inBlock = false
continue
}
var m []string
if !inBlock {
if !strings.HasPrefix(line, "import ") {
continue
}
m = importRE.FindStringSubmatch(line)
if m == nil {
fatalf("%s:%d: invalid import declaration: %q", srcFile, i+1, line)
}
} else {
m = importBlockRE.FindStringSubmatch(line)
if m == nil {
fatalf("%s:%d: invalid import block line", srcFile, i+1)
}
if m[2] == "" {
continue
}
}
path := m[2]
if strings.HasPrefix(path, "cmd/") {
path = "bootstrap/" + path
} else {
for _, dir := range bootstrapDirs {
if path == dir {
path = "bootstrap/" + dir
break
}
}
}
// Rewrite use of internal/reflectlite to be plain reflect.
if path == "internal/reflectlite" {
lines[i] = strings.ReplaceAll(line, `"reflect"`, `reflectlite "reflect"`)
continue
}
// Otherwise, reject direct imports of internal packages,
// since that implies knowledge of internal details that might
// change from one bootstrap toolchain to the next.
// There are many internal packages that are listed in
// bootstrapDirs and made into bootstrap copies based on the
// current repo's source code. Those are fine; this is catching
// references to internal packages in the older bootstrap toolchain.
if strings.HasPrefix(path, "internal/") {
fatalf("%s:%d: bootstrap-copied source file cannot import %s", srcFile, i+1, path)
}
if path != m[2] {
lines[i] = strings.ReplaceAll(line, `"`+m[2]+`"`, `"`+path+`"`)
}
}
lines[0] = generatedHeader + "// This is a bootstrap copy of " + srcFile + "\n\n//line " + srcFile + ":1\n" + lines[0]
return strings.Join(lines, "")
}
