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Source file src/cmd/dist/buildtool.go

Documentation: cmd/dist

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

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