Source file src/pkg/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 have 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.
    31	// These will be imported during bootstrap as bootstrap/name, like bootstrap/math/big.
    32	var bootstrapDirs = []string{
    33		"cmd/asm",
    34		"cmd/asm/internal/arch",
    35		"cmd/asm/internal/asm",
    36		"cmd/asm/internal/flags",
    37		"cmd/asm/internal/lex",
    38		"cmd/cgo",
    39		"cmd/compile",
    40		"cmd/compile/internal/amd64",
    41		"cmd/compile/internal/arm",
    42		"cmd/compile/internal/arm64",
    43		"cmd/compile/internal/gc",
    44		"cmd/compile/internal/mips",
    45		"cmd/compile/internal/mips64",
    46		"cmd/compile/internal/ppc64",
    47		"cmd/compile/internal/types",
    48		"cmd/compile/internal/s390x",
    49		"cmd/compile/internal/ssa",
    50		"cmd/compile/internal/syntax",
    51		"cmd/compile/internal/x86",
    52		"cmd/compile/internal/wasm",
    53		"cmd/internal/bio",
    54		"cmd/internal/gcprog",
    55		"cmd/internal/dwarf",
    56		"cmd/internal/edit",
    57		"cmd/internal/objabi",
    58		"cmd/internal/obj",
    59		"cmd/internal/obj/arm",
    60		"cmd/internal/obj/arm64",
    61		"cmd/internal/obj/mips",
    62		"cmd/internal/obj/ppc64",
    63		"cmd/internal/obj/s390x",
    64		"cmd/internal/obj/x86",
    65		"cmd/internal/obj/wasm",
    66		"cmd/internal/src",
    67		"cmd/internal/sys",
    68		"cmd/link",
    69		"cmd/link/internal/amd64",
    70		"cmd/link/internal/arm",
    71		"cmd/link/internal/arm64",
    72		"cmd/link/internal/ld",
    73		"cmd/link/internal/loadelf",
    74		"cmd/link/internal/loadmacho",
    75		"cmd/link/internal/loadpe",
    76		"cmd/link/internal/loadxcoff",
    77		"cmd/link/internal/mips",
    78		"cmd/link/internal/mips64",
    79		"cmd/link/internal/objfile",
    80		"cmd/link/internal/ppc64",
    81		"cmd/link/internal/s390x",
    82		"cmd/link/internal/sym",
    83		"cmd/link/internal/x86",
    84		"compress/flate",
    85		"compress/zlib",
    86		"cmd/link/internal/wasm",
    87		"container/heap",
    88		"debug/dwarf",
    89		"debug/elf",
    90		"debug/macho",
    91		"debug/pe",
    92		"internal/goversion",
    93		"internal/race",
    94		"internal/xcoff",
    95		"math/big",
    96		"math/bits",
    97		"sort",
    98	}
    99	
   100	// File prefixes that are ignored by go/build anyway, and cause
   101	// problems with editor generated temporary files (#18931).
   102	var ignorePrefixes = []string{
   103		".",
   104		"_",
   105	}
   106	
   107	// File suffixes that use build tags introduced since Go 1.4.
   108	// These must not be copied into the bootstrap build directory.
   109	var ignoreSuffixes = []string{
   110		"_arm64.s",
   111		"_arm64.go",
   112		"_wasm.s",
   113		"_wasm.go",
   114	}
   115	
   116	func bootstrapBuildTools() {
   117		goroot_bootstrap := os.Getenv("GOROOT_BOOTSTRAP")
   118		if goroot_bootstrap == "" {
   119			goroot_bootstrap = pathf("%s/go1.4", os.Getenv("HOME"))
   120		}
   121		xprintf("Building Go toolchain1 using %s.\n", goroot_bootstrap)
   122	
   123		mkzbootstrap(pathf("%s/src/cmd/internal/objabi/zbootstrap.go", goroot))
   124	
   125		// Use $GOROOT/pkg/bootstrap as the bootstrap workspace root.
   126		// We use a subdirectory of $GOROOT/pkg because that's the
   127		// space within $GOROOT where we store all generated objects.
   128		// We could use a temporary directory outside $GOROOT instead,
   129		// but it is easier to debug on failure if the files are in a known location.
   130		workspace := pathf("%s/pkg/bootstrap", goroot)
   131		xremoveall(workspace)
   132		xatexit(func() { xremoveall(workspace) })
   133		base := pathf("%s/src/bootstrap", workspace)
   134		xmkdirall(base)
   135	
   136		// Copy source code into $GOROOT/pkg/bootstrap and rewrite import paths.
   137		writefile("module bootstrap\n", pathf("%s/%s", base, "go.mod"), 0)
   138		for _, dir := range bootstrapDirs {
   139			src := pathf("%s/src/%s", goroot, dir)
   140			dst := pathf("%s/%s", base, dir)
   141			xmkdirall(dst)
   142			if dir == "cmd/cgo" {
   143				// Write to src because we need the file both for bootstrap
   144				// and for later in the main build.
   145				mkzdefaultcc("", pathf("%s/zdefaultcc.go", src))
   146			}
   147		Dir:
   148			for _, name := range xreaddirfiles(src) {
   149				for _, pre := range ignorePrefixes {
   150					if strings.HasPrefix(name, pre) {
   151						continue Dir
   152					}
   153				}
   154				for _, suf := range ignoreSuffixes {
   155					if strings.HasSuffix(name, suf) {
   156						continue Dir
   157					}
   158				}
   159				srcFile := pathf("%s/%s", src, name)
   160				dstFile := pathf("%s/%s", dst, name)
   161				text := bootstrapRewriteFile(srcFile)
   162				writefile(text, dstFile, 0)
   163			}
   164		}
   165	
   166		// Set up environment for invoking Go 1.4 go command.
   167		// GOROOT points at Go 1.4 GOROOT,
   168		// GOPATH points at our bootstrap workspace,
   169		// GOBIN is empty, so that binaries are installed to GOPATH/bin,
   170		// and GOOS, GOHOSTOS, GOARCH, and GOHOSTOS are empty,
   171		// so that Go 1.4 builds whatever kind of binary it knows how to build.
   172		// Restore GOROOT, GOPATH, and GOBIN when done.
   173		// Don't bother with GOOS, GOHOSTOS, GOARCH, and GOHOSTARCH,
   174		// because setup will take care of those when bootstrapBuildTools returns.
   175	
   176		defer os.Setenv("GOROOT", os.Getenv("GOROOT"))
   177		os.Setenv("GOROOT", goroot_bootstrap)
   178	
   179		defer os.Setenv("GOPATH", os.Getenv("GOPATH"))
   180		os.Setenv("GOPATH", workspace)
   181	
   182		defer os.Setenv("GOBIN", os.Getenv("GOBIN"))
   183		os.Setenv("GOBIN", "")
   184	
   185		os.Setenv("GOOS", "")
   186		os.Setenv("GOHOSTOS", "")
   187		os.Setenv("GOARCH", "")
   188		os.Setenv("GOHOSTARCH", "")
   189	
   190		// Run Go 1.4 to build binaries. Use -gcflags=-l to disable inlining to
   191		// workaround bugs in Go 1.4's compiler. See discussion thread:
   192		// https://groups.google.com/d/msg/golang-dev/Ss7mCKsvk8w/Gsq7VYI0AwAJ
   193		// Use the math_big_pure_go build tag to disable the assembly in math/big
   194		// which may contain unsupported instructions.
   195		// Note that if we are using Go 1.10 or later as bootstrap, the -gcflags=-l
   196		// only applies to the final cmd/go binary, but that's OK: if this is Go 1.10
   197		// or later we don't need to disable inlining to work around bugs in the Go 1.4 compiler.
   198		cmd := []string{
   199			pathf("%s/bin/go", goroot_bootstrap),
   200			"install",
   201			"-gcflags=-l",
   202			"-tags=math_big_pure_go compiler_bootstrap",
   203		}
   204		if vflag > 0 {
   205			cmd = append(cmd, "-v")
   206		}
   207		if tool := os.Getenv("GOBOOTSTRAP_TOOLEXEC"); tool != "" {
   208			cmd = append(cmd, "-toolexec="+tool)
   209		}
   210		cmd = append(cmd, "bootstrap/cmd/...")
   211		run(base, ShowOutput|CheckExit, cmd...)
   212	
   213		// Copy binaries into tool binary directory.
   214		for _, name := range bootstrapDirs {
   215			if !strings.HasPrefix(name, "cmd/") {
   216				continue
   217			}
   218			name = name[len("cmd/"):]
   219			if !strings.Contains(name, "/") {
   220				copyfile(pathf("%s/%s%s", tooldir, name, exe), pathf("%s/bin/%s%s", workspace, name, exe), writeExec)
   221			}
   222		}
   223	
   224		if vflag > 0 {
   225			xprintf("\n")
   226		}
   227	}
   228	
   229	var ssaRewriteFileSubstring = filepath.FromSlash("src/cmd/compile/internal/ssa/rewrite")
   230	
   231	// isUnneededSSARewriteFile reports whether srcFile is a
   232	// src/cmd/compile/internal/ssa/rewriteARCHNAME.go file for an
   233	// architecture that isn't for the current runtime.GOARCH.
   234	//
   235	// When unneeded is true archCaps is the rewrite base filename without
   236	// the "rewrite" prefix or ".go" suffix: AMD64, 386, ARM, ARM64, etc.
   237	func isUnneededSSARewriteFile(srcFile string) (archCaps string, unneeded bool) {
   238		if !strings.Contains(srcFile, ssaRewriteFileSubstring) {
   239			return "", false
   240		}
   241		fileArch := strings.TrimSuffix(strings.TrimPrefix(filepath.Base(srcFile), "rewrite"), ".go")
   242		if fileArch == "" {
   243			return "", false
   244		}
   245		b := fileArch[0]
   246		if b == '_' || ('a' <= b && b <= 'z') {
   247			return "", false
   248		}
   249		archCaps = fileArch
   250		fileArch = strings.ToLower(fileArch)
   251		fileArch = strings.TrimSuffix(fileArch, "splitload")
   252		if fileArch == strings.TrimSuffix(runtime.GOARCH, "le") {
   253			return "", false
   254		}
   255		if fileArch == strings.TrimSuffix(os.Getenv("GOARCH"), "le") {
   256			return "", false
   257		}
   258		return archCaps, true
   259	}
   260	
   261	func bootstrapRewriteFile(srcFile string) string {
   262		// During bootstrap, generate dummy rewrite files for
   263		// irrelevant architectures. We only need to build a bootstrap
   264		// binary that works for the current runtime.GOARCH.
   265		// This saves 6+ seconds of bootstrap.
   266		if archCaps, ok := isUnneededSSARewriteFile(srcFile); ok {
   267			return fmt.Sprintf(`// Code generated by go tool dist; DO NOT EDIT.
   268	
   269	package ssa
   270	
   271	func rewriteValue%s(v *Value) bool { panic("unused during bootstrap") }
   272	func rewriteBlock%s(b *Block) bool { panic("unused during bootstrap") }
   273	`, archCaps, archCaps)
   274		}
   275	
   276		return bootstrapFixImports(srcFile)
   277	}
   278	
   279	func bootstrapFixImports(srcFile string) string {
   280		lines := strings.SplitAfter(readfile(srcFile), "\n")
   281		inBlock := false
   282		for i, line := range lines {
   283			if strings.HasPrefix(line, "import (") {
   284				inBlock = true
   285				continue
   286			}
   287			if inBlock && strings.HasPrefix(line, ")") {
   288				inBlock = false
   289				continue
   290			}
   291			if strings.HasPrefix(line, `import "`) || strings.HasPrefix(line, `import . "`) ||
   292				inBlock && (strings.HasPrefix(line, "\t\"") || strings.HasPrefix(line, "\t. \"")) {
   293				line = strings.Replace(line, `"cmd/`, `"bootstrap/cmd/`, -1)
   294				for _, dir := range bootstrapDirs {
   295					if strings.HasPrefix(dir, "cmd/") {
   296						continue
   297					}
   298					line = strings.Replace(line, `"`+dir+`"`, `"bootstrap/`+dir+`"`, -1)
   299				}
   300				lines[i] = line
   301			}
   302		}
   303	
   304		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]
   305	
   306		return strings.Join(lines, "")
   307	}
   308	

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