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// 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 1.4.
//
// The general strategy is to copy the source files we need into
// a new GOPATH workspace, adjust import paths appropriately,
// invoke the Go 1.4 go command to build those sources,
// and then copy the binaries back.
package main
import (
"fmt"
"os"
"path/filepath"
"runtime"
"strings"
)
// bootstrapDirs is a list of directories holding code that must be
// compiled with a Go 1.4 toolchain to produce the bootstrapTargets.
// All directories in this list are relative to and must be below $GOROOT/src.
//
// The list has have 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 1.4 copy when used
// by the command packages.
// These will be imported during bootstrap as bootstrap/name, like bootstrap/math/big.
var bootstrapDirs = []string{
"cmd/asm",
"cmd/asm/internal/arch",
"cmd/asm/internal/asm",
"cmd/asm/internal/flags",
"cmd/asm/internal/lex",
"cmd/cgo",
"cmd/compile",
"cmd/compile/internal/amd64",
"cmd/compile/internal/arm",
"cmd/compile/internal/arm64",
"cmd/compile/internal/gc",
"cmd/compile/internal/logopt",
"cmd/compile/internal/mips",
"cmd/compile/internal/mips64",
"cmd/compile/internal/ppc64",
"cmd/compile/internal/riscv64",
"cmd/compile/internal/s390x",
"cmd/compile/internal/ssa",
"cmd/compile/internal/syntax",
"cmd/compile/internal/types",
"cmd/compile/internal/x86",
"cmd/compile/internal/wasm",
"cmd/internal/bio",
"cmd/internal/gcprog",
"cmd/internal/dwarf",
"cmd/internal/edit",
"cmd/internal/goobj2",
"cmd/internal/objabi",
"cmd/internal/obj",
"cmd/internal/obj/arm",
"cmd/internal/obj/arm64",
"cmd/internal/obj/mips",
"cmd/internal/obj/ppc64",
"cmd/internal/obj/riscv",
"cmd/internal/obj/s390x",
"cmd/internal/obj/x86",
"cmd/internal/obj/wasm",
"cmd/internal/src",
"cmd/internal/sys",
"cmd/link",
"cmd/link/internal/amd64",
"cmd/link/internal/arm",
"cmd/link/internal/arm64",
"cmd/link/internal/ld",
"cmd/link/internal/loadelf",
"cmd/link/internal/loader",
"cmd/link/internal/loadmacho",
"cmd/link/internal/loadpe",
"cmd/link/internal/loadxcoff",
"cmd/link/internal/mips",
"cmd/link/internal/mips64",
"cmd/link/internal/objfile",
"cmd/link/internal/ppc64",
"cmd/link/internal/riscv64",
"cmd/link/internal/s390x",
"cmd/link/internal/sym",
"cmd/link/internal/x86",
"compress/flate",
"compress/zlib",
"cmd/link/internal/wasm",
"container/heap",
"debug/dwarf",
"debug/elf",
"debug/macho",
"debug/pe",
"internal/goversion",
"internal/race",
"internal/xcoff",
"math/big",
"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 1.4.
// These must not be copied into the bootstrap build directory.
var ignoreSuffixes = []string{
"_arm64.s",
"_arm64.go",
"_wasm.s",
"_wasm.go",
}
func bootstrapBuildTools() {
goroot_bootstrap := os.Getenv("GOROOT_BOOTSTRAP")
if goroot_bootstrap == "" {
goroot_bootstrap = pathf("%s/go1.4", os.Getenv("HOME"))
}
xprintf("Building Go toolchain1 using %s.\n", goroot_bootstrap)
mkzbootstrap(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.
writefile("module bootstrap\n", pathf("%s/%s", base, "go.mod"), 0)
for _, dir := range bootstrapDirs {
src := pathf("%s/src/%s", goroot, dir)
dst := pathf("%s/%s", base, dir)
xmkdirall(dst)
if dir == "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))
}
Dir:
for _, name := range xreaddirfiles(src) {
for _, pre := range ignorePrefixes {
if strings.HasPrefix(name, pre) {
continue Dir
}
}
for _, suf := range ignoreSuffixes {
if strings.HasSuffix(name, suf) {
continue Dir
}
}
srcFile := pathf("%s/%s", src, name)
dstFile := pathf("%s/%s", dst, name)
text := bootstrapRewriteFile(srcFile)
writefile(text, dstFile, 0)
}
}
// Set up environment for invoking Go 1.4 go command.
// GOROOT points at Go 1.4 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 1.4 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 1.4 to build binaries. Use -gcflags=-l to disable inlining to
// workaround bugs in Go 1.4's compiler. See discussion thread:
// https://groups.google.com/d/msg/golang-dev/Ss7mCKsvk8w/Gsq7VYI0AwAJ
// Use the math_big_pure_go build tag to disable the assembly in math/big
// which may contain unsupported instructions.
// Note that if we are using Go 1.10 or later as bootstrap, the -gcflags=-l
// only applies to the final cmd/go binary, but that's OK: if this is Go 1.10
// or later we don't need to disable inlining to work around bugs in the Go 1.4 compiler.
cmd := []string{
pathf("%s/bin/go", goroot_bootstrap),
"install",
"-gcflags=-l",
"-tags=math_big_pure_go compiler_bootstrap",
}
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 current runtime.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 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")
if fileArch == os.Getenv("GOHOSTARCH") {
return "", false
}
if fileArch == strings.TrimSuffix(runtime.GOARCH, "le") {
return "", false
}
if fileArch == strings.TrimSuffix(os.Getenv("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 runtime.GOARCH.
// This saves 6+ seconds of bootstrap.
if archCaps, ok := isUnneededSSARewriteFile(srcFile); ok {
return fmt.Sprintf(`// Code generated by go tool dist; DO NOT EDIT.
package ssa
func rewriteValue%s(v *Value) bool { panic("unused during bootstrap") }
func rewriteBlock%s(b *Block) bool { panic("unused during bootstrap") }
`, archCaps, archCaps)
}
return bootstrapFixImports(srcFile)
}
func bootstrapFixImports(srcFile string) string {
lines := strings.SplitAfter(readfile(srcFile), "\n")
inBlock := false
for i, line := range lines {
if strings.HasPrefix(line, "import (") {
inBlock = true
continue
}
if inBlock && strings.HasPrefix(line, ")") {
inBlock = false
continue
}
if strings.HasPrefix(line, `import "`) || strings.HasPrefix(line, `import . "`) ||
inBlock && (strings.HasPrefix(line, "\t\"") || strings.HasPrefix(line, "\t. \"")) {
line = strings.Replace(line, `"cmd/`, `"bootstrap/cmd/`, -1)
for _, dir := range bootstrapDirs {
if strings.HasPrefix(dir, "cmd/") {
continue
}
line = strings.Replace(line, `"`+dir+`"`, `"bootstrap/`+dir+`"`, -1)
}
lines[i] = line
}
}
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]
return strings.Join(lines, "")
}