src/pkg/go/build/build.go - go - Git at Google

 // Copyright 2011 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.

 // Package build provides tools for building Go packages.
 package build

 import (
 	"bytes"
 	"exec"
 	"fmt"
 	"os"
 	"path/filepath"
 	"regexp"
 	"runtime"
 	"strings"
 )

 // Build produces a build Script for the given package.
 func Build(tree *Tree, pkg string, info *DirInfo) (*Script, os.Error) {
 	s := &Script{}
 	b := &build{
 		script: s,
 		path:   filepath.Join(tree.SrcDir(), pkg),
 	}
 	b.obj = b.abs("_obj") + string(filepath.Separator)

 	b.goarch = runtime.GOARCH
 	if g := os.Getenv("GOARCH"); g != "" {
 		b.goarch = g
 	}
 	var err os.Error
 	b.arch, err = ArchChar(b.goarch)
 	if err != nil {
 		return nil, err
 	}

 	// add import object files to list of Inputs
 	for _, pkg := range info.Imports {
 		t, p, err := FindTree(pkg)
 		if err != nil && err != ErrNotFound {
 			// FindTree should always be able to suggest an import
 			// path and tree. The path must be malformed
 			// (for example, an absolute or relative path).
 			return nil, os.NewError("build: invalid import: " + pkg)
 		}
 		s.addInput(filepath.Join(t.PkgDir(), p+".a"))
 	}

 	// .go files to be built with gc
 	gofiles := b.abss(info.GoFiles...)
 	s.addInput(gofiles...)

 	var ofiles []string // object files to be linked or packed

 	// make build directory
 	b.mkdir(b.obj)
 	s.addIntermediate(b.obj)

 	// cgo
 	if len(info.CgoFiles) > 0 {
 		cgoFiles := b.abss(info.CgoFiles...)
 		s.addInput(cgoFiles...)
 		outGo, outObj := b.cgo(cgoFiles)
 		gofiles = append(gofiles, outGo...)
 		ofiles = append(ofiles, outObj...)
 		s.addIntermediate(outGo...)
 		s.addIntermediate(outObj...)
 	}

 	// compile
 	if len(gofiles) > 0 {
 		ofile := b.obj + "_go_." + b.arch
 		b.gc(ofile, gofiles...)
 		ofiles = append(ofiles, ofile)
 		s.addIntermediate(ofile)
 	}

 	// assemble
 	for _, sfile := range info.SFiles {
 		ofile := b.obj + sfile[:len(sfile)-1] + b.arch
 		sfile = b.abs(sfile)
 		s.addInput(sfile)
 		b.asm(ofile, sfile)
 		ofiles = append(ofiles, ofile)
 		s.addIntermediate(ofile)
 	}

 	if len(ofiles) == 0 {
 		return nil, os.NewError("make: no object files to build")
 	}

 	// choose target file
 	var targ string
 	if info.IsCommand() {
 		// use the last part of the import path as binary name
 		_, bin := filepath.Split(pkg)
 		if runtime.GOOS == "windows" {
 			bin += ".exe"
 		}
 		targ = filepath.Join(tree.BinDir(), bin)
 	} else {
 		targ = filepath.Join(tree.PkgDir(), pkg+".a")
 	}

 	// make target directory
 	targDir, _ := filepath.Split(targ)
 	b.mkdir(targDir)

 	// link binary or pack object
 	if info.IsCommand() {
 		b.ld(targ, ofiles...)
 	} else {
 		b.gopack(targ, ofiles...)
 	}
 	s.Output = append(s.Output, targ)

 	return b.script, nil
 }

 // A Script describes the build process for a Go package.
 // The Input, Intermediate, and Output fields are lists of absolute paths.
 type Script struct {
 	Cmd          []*Cmd
 	Input        []string
 	Intermediate []string
 	Output       []string
 }

 func (s *Script) addInput(file ...string) {
 	s.Input = append(s.Input, file...)
 }

 func (s *Script) addIntermediate(file ...string) {
 	s.Intermediate = append(s.Intermediate, file...)
 }

 // Run runs the Script's Cmds in order.
 func (s *Script) Run() os.Error {
 	for _, c := range s.Cmd {
 		if err := c.Run(); err != nil {
 			return err
 		}
 	}
 	return nil
 }

 // Stale returns true if the build's inputs are newer than its outputs.
 func (s *Script) Stale() bool {
 	var latest int64
 	// get latest mtime of outputs
 	for _, file := range s.Output {
 		fi, err := os.Stat(file)
 		if err != nil {
 			// any error reading output files means stale
 			return true
 		}
 		if m := fi.Mtime_ns; m > latest {
 			latest = m
 		}
 	}
 	for _, file := range s.Input {
 		fi, err := os.Stat(file)
 		if err != nil || fi.Mtime_ns > latest {
 			// any error reading input files means stale
 			// (attempt to rebuild to figure out why)
 			return true
 		}
 	}
 	return false
 }

 // Clean removes the Script's Intermediate files.
 // It tries to remove every file and returns the first error it encounters.
 func (s *Script) Clean() (err os.Error) {
 	// Reverse order so that directories get removed after the files they contain.
 	for i := len(s.Intermediate) - 1; i >= 0; i-- {
 		if e := os.Remove(s.Intermediate[i]); err == nil {
 			err = e
 		}
 	}
 	return
 }

 // Clean removes the Script's Intermediate and Output files.
 // It tries to remove every file and returns the first error it encounters.
 func (s *Script) Nuke() (err os.Error) {
 	// Reverse order so that directories get removed after the files they contain.
 	for i := len(s.Output) - 1; i >= 0; i-- {
 		if e := os.Remove(s.Output[i]); err == nil {
 			err = e
 		}
 	}
 	if e := s.Clean(); err == nil {
 		err = e
 	}
 	return
 }

 // A Cmd describes an individual build command.
 type Cmd struct {
 	Args   []string // command-line
 	Stdout string   // write standard output to this file, "" is passthrough
 	Dir    string   // working directory
 	Env    []string // environment
 	Input  []string // file paths (dependencies)
 	Output []string // file paths
 }

 func (c *Cmd) String() string {
 	return strings.Join(c.Args, " ")
 }

 // Run executes the Cmd.
 func (c *Cmd) Run() os.Error {
 	out := new(bytes.Buffer)
 	cmd := exec.Command(c.Args[0], c.Args[1:]...)
 	cmd.Dir = c.Dir
 	cmd.Env = c.Env
 	cmd.Stdout = out
 	cmd.Stderr = out
 	if c.Stdout != "" {
 		f, err := os.Create(c.Stdout)
 		if err != nil {
 			return err
 		}
 		defer f.Close()
 		cmd.Stdout = f
 	}
 	if err := cmd.Run(); err != nil {
 		return fmt.Errorf("command %q: %v\n%v", c, err, out)
 	}
 	return nil
 }

 // ArchChar returns the architecture character for the given goarch.
 // For example, ArchChar("amd64") returns "6".
 func ArchChar(goarch string) (string, os.Error) {
 	switch goarch {
 	case "386":
 		return "8", nil
 	case "amd64":
 		return "6", nil
 	case "arm":
 		return "5", nil
 	}
 	return "", os.NewError("unsupported GOARCH " + goarch)
 }

 type build struct {
 	script *Script
 	path   string
 	obj    string
 	goarch string
 	arch   string
 }

 func (b *build) abs(file string) string {
 	if filepath.IsAbs(file) {
 		return file
 	}
 	return filepath.Join(b.path, file)
 }

 func (b *build) abss(file ...string) []string {
 	s := make([]string, len(file))
 	for i, f := range file {
 		s[i] = b.abs(f)
 	}
 	return s
 }

 func (b *build) add(c Cmd) {
 	b.script.Cmd = append(b.script.Cmd, &c)
 }

 func (b *build) mkdir(name string) {
 	b.add(Cmd{
 		Args:   []string{"mkdir", "-p", name},
 		Output: []string{name},
 	})
 }

 func (b *build) gc(ofile string, gofiles ...string) {
 	gc := b.arch + "g"
 	args := append([]string{gc, "-o", ofile}, gcImportArgs...)
 	args = append(args, gofiles...)
 	b.add(Cmd{
 		Args:   args,
 		Input:  gofiles,
 		Output: []string{ofile},
 	})
 }

 func (b *build) asm(ofile string, sfile string) {
 	asm := b.arch + "a"
 	b.add(Cmd{
 		Args:   []string{asm, "-o", ofile, sfile},
 		Input:  []string{sfile},
 		Output: []string{ofile},
 	})
 }

 func (b *build) ld(targ string, ofiles ...string) {
 	ld := b.arch + "l"
 	args := append([]string{ld, "-o", targ}, ldImportArgs...)
 	args = append(args, ofiles...)
 	b.add(Cmd{
 		Args:   args,
 		Input:  ofiles,
 		Output: []string{targ},
 	})
 }

 func (b *build) gopack(targ string, ofiles ...string) {
 	b.add(Cmd{
 		Args:   append([]string{"gopack", "grc", targ}, ofiles...),
 		Input:  ofiles,
 		Output: []string{targ},
 	})
 }

 func (b *build) cc(ofile string, cfiles ...string) {
 	cc := b.arch + "c"
 	dir := fmt.Sprintf("%s_%s", runtime.GOOS, runtime.GOARCH)
 	inc := filepath.Join(runtime.GOROOT(), "pkg", dir)
 	args := []string{cc, "-FVw", "-I", inc, "-o", ofile}
 	b.add(Cmd{
 		Args:   append(args, cfiles...),
 		Input:  cfiles,
 		Output: []string{ofile},
 	})
 }

 func (b *build) gccCompile(ofile, cfile string) {
 	b.add(Cmd{
 		Args:   b.gccArgs("-o", ofile, "-c", cfile),
 		Input:  []string{cfile},
 		Output: []string{ofile},
 	})
 }

 func (b *build) gccLink(ofile string, ofiles ...string) {
 	b.add(Cmd{
 		Args:   append(b.gccArgs("-o", ofile), ofiles...),
 		Input:  ofiles,
 		Output: []string{ofile},
 	})
 }

 func (b *build) gccArgs(args ...string) []string {
 	// TODO(adg): HOST_CC
 	a := []string{"gcc", "-I", b.path, "-g", "-fPIC", "-O2"}
 	switch b.arch {
 	case "8":
 		a = append(a, "-m32")
 	case "6":
 		a = append(a, "-m64")
 	}
 	return append(a, args...)
 }

 var cgoRe = regexp.MustCompile(`[/\\:]`)

 func (b *build) cgo(cgofiles []string) (outGo, outObj []string) {
 	// cgo
 	// TODO(adg): CGOPKGPATH
 	// TODO(adg): CGO_FLAGS
 	gofiles := []string{b.obj + "_cgo_gotypes.go"}
 	cfiles := []string{b.obj + "_cgo_main.c", b.obj + "_cgo_export.c"}
 	for _, fn := range cgofiles {
 		f := b.obj + cgoRe.ReplaceAllString(fn[:len(fn)-2], "_")
 		gofiles = append(gofiles, f+"cgo1.go")
 		cfiles = append(cfiles, f+"cgo2.c")
 	}
 	defunC := b.obj + "_cgo_defun.c"
 	output := append([]string{defunC}, cfiles...)
 	output = append(output, gofiles...)
 	b.add(Cmd{
 		Args:   append([]string{"cgo", "--"}, cgofiles...),
 		Dir:    b.path,
 		Env:    append(os.Environ(), "GOARCH="+b.goarch),
 		Input:  cgofiles,
 		Output: output,
 	})
 	outGo = append(outGo, gofiles...)
 	exportH := filepath.Join(b.path, "_cgo_export.h")
 	b.script.addIntermediate(defunC, exportH, b.obj+"_cgo_flags")
 	b.script.addIntermediate(cfiles...)

 	// cc _cgo_defun.c
 	defunObj := b.obj + "_cgo_defun." + b.arch
 	b.cc(defunObj, defunC)
 	outObj = append(outObj, defunObj)

 	// gcc
 	linkobj := make([]string, 0, len(cfiles))
 	for _, cfile := range cfiles {
 		ofile := cfile[:len(cfile)-1] + "o"
 		b.gccCompile(ofile, cfile)
 		linkobj = append(linkobj, ofile)
 		if !strings.HasSuffix(ofile, "_cgo_main.o") {
 			outObj = append(outObj, ofile)
 		} else {
 			b.script.addIntermediate(ofile)
 		}
 	}
 	dynObj := b.obj + "_cgo_.o"
 	b.gccLink(dynObj, linkobj...)
 	b.script.addIntermediate(dynObj)

 	// cgo -dynimport
 	importC := b.obj + "_cgo_import.c"
 	b.add(Cmd{
 		Args:   []string{"cgo", "-dynimport", dynObj},
 		Stdout: importC,
 		Input:  []string{dynObj},
 		Output: []string{importC},
 	})
 	b.script.addIntermediate(importC)

 	// cc _cgo_import.ARCH
 	importObj := b.obj + "_cgo_import." + b.arch
 	b.cc(importObj, importC)
 	outObj = append(outObj, importObj)

 	return
 }
	// Copyright 2011 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.

	// Package build provides tools for building Go packages.
	package build

	import (
	"bytes"
	"exec"
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"runtime"
	"strings"
	)

	// Build produces a build Script for the given package.
	func Build(tree Tree, pkg string, info DirInfo) (*Script, os.Error) {
	s := &Script{}
	b := &build{
	script: s,
	path: filepath.Join(tree.SrcDir(), pkg),
	}
	b.obj = b.abs("_obj") + string(filepath.Separator)

	b.goarch = runtime.GOARCH
	if g := os.Getenv("GOARCH"); g != "" {
	b.goarch = g
	}
	var err os.Error
	b.arch, err = ArchChar(b.goarch)
	if err != nil {
	return nil, err
	}

	// add import object files to list of Inputs
	for _, pkg := range info.Imports {
	t, p, err := FindTree(pkg)
	if err != nil && err != ErrNotFound {
	// FindTree should always be able to suggest an import
	// path and tree. The path must be malformed
	// (for example, an absolute or relative path).
	return nil, os.NewError("build: invalid import: " + pkg)
	}
	s.addInput(filepath.Join(t.PkgDir(), p+".a"))
	}

	// .go files to be built with gc
	gofiles := b.abss(info.GoFiles...)
	s.addInput(gofiles...)

	var ofiles []string // object files to be linked or packed

	// make build directory
	b.mkdir(b.obj)
	s.addIntermediate(b.obj)

	// cgo
	if len(info.CgoFiles) > 0 {
	cgoFiles := b.abss(info.CgoFiles...)
	s.addInput(cgoFiles...)
	outGo, outObj := b.cgo(cgoFiles)
	gofiles = append(gofiles, outGo...)
	ofiles = append(ofiles, outObj...)
	s.addIntermediate(outGo...)
	s.addIntermediate(outObj...)
	}

	// compile
	if len(gofiles) > 0 {
	ofile := b.obj + "_go_." + b.arch
	b.gc(ofile, gofiles...)
	ofiles = append(ofiles, ofile)
	s.addIntermediate(ofile)
	}

	// assemble
	for _, sfile := range info.SFiles {
	ofile := b.obj + sfile[:len(sfile)-1] + b.arch
	sfile = b.abs(sfile)
	s.addInput(sfile)
	b.asm(ofile, sfile)
	ofiles = append(ofiles, ofile)
	s.addIntermediate(ofile)
	}

	if len(ofiles) == 0 {
	return nil, os.NewError("make: no object files to build")
	}

	// choose target file
	var targ string
	if info.IsCommand() {
	// use the last part of the import path as binary name
	_, bin := filepath.Split(pkg)
	if runtime.GOOS == "windows" {
	bin += ".exe"
	}
	targ = filepath.Join(tree.BinDir(), bin)
	} else {
	targ = filepath.Join(tree.PkgDir(), pkg+".a")
	}

	// make target directory
	targDir, _ := filepath.Split(targ)
	b.mkdir(targDir)

	// link binary or pack object
	if info.IsCommand() {
	b.ld(targ, ofiles...)
	} else {
	b.gopack(targ, ofiles...)
	}
	s.Output = append(s.Output, targ)

	return b.script, nil
	}

	// A Script describes the build process for a Go package.
	// The Input, Intermediate, and Output fields are lists of absolute paths.
	type Script struct {
	Cmd []*Cmd
	Input []string
	Intermediate []string
	Output []string
	}

	func (s *Script) addInput(file ...string) {
	s.Input = append(s.Input, file...)
	}

	func (s *Script) addIntermediate(file ...string) {
	s.Intermediate = append(s.Intermediate, file...)
	}

	// Run runs the Script's Cmds in order.
	func (s *Script) Run() os.Error {
	for _, c := range s.Cmd {
	if err := c.Run(); err != nil {
	return err
	}
	}
	return nil
	}

	// Stale returns true if the build's inputs are newer than its outputs.
	func (s *Script) Stale() bool {
	var latest int64
	// get latest mtime of outputs
	for _, file := range s.Output {
	fi, err := os.Stat(file)
	if err != nil {
	// any error reading output files means stale
	return true
	}
	if m := fi.Mtime_ns; m > latest {
	latest = m
	}
	}
	for _, file := range s.Input {
	fi, err := os.Stat(file)
	if err != nil \|\| fi.Mtime_ns > latest {
	// any error reading input files means stale
	// (attempt to rebuild to figure out why)
	return true
	}
	}
	return false
	}

	// Clean removes the Script's Intermediate files.
	// It tries to remove every file and returns the first error it encounters.
	func (s *Script) Clean() (err os.Error) {
	// Reverse order so that directories get removed after the files they contain.
	for i := len(s.Intermediate) - 1; i >= 0; i-- {
	if e := os.Remove(s.Intermediate[i]); err == nil {
	err = e
	}
	}
	return
	}

	// Clean removes the Script's Intermediate and Output files.
	// It tries to remove every file and returns the first error it encounters.
	func (s *Script) Nuke() (err os.Error) {
	// Reverse order so that directories get removed after the files they contain.
	for i := len(s.Output) - 1; i >= 0; i-- {
	if e := os.Remove(s.Output[i]); err == nil {
	err = e
	}
	}
	if e := s.Clean(); err == nil {
	err = e
	}
	return
	}

	// A Cmd describes an individual build command.
	type Cmd struct {
	Args []string // command-line
	Stdout string // write standard output to this file, "" is passthrough
	Dir string // working directory
	Env []string // environment
	Input []string // file paths (dependencies)
	Output []string // file paths
	}

	func (c *Cmd) String() string {
	return strings.Join(c.Args, " ")
	}

	// Run executes the Cmd.
	func (c *Cmd) Run() os.Error {
	out := new(bytes.Buffer)
	cmd := exec.Command(c.Args[0], c.Args[1:]...)
	cmd.Dir = c.Dir
	cmd.Env = c.Env
	cmd.Stdout = out
	cmd.Stderr = out
	if c.Stdout != "" {
	f, err := os.Create(c.Stdout)
	if err != nil {
	return err
	}
	defer f.Close()
	cmd.Stdout = f
	}
	if err := cmd.Run(); err != nil {
	return fmt.Errorf("command %q: %v\n%v", c, err, out)
	}
	return nil
	}

	// ArchChar returns the architecture character for the given goarch.
	// For example, ArchChar("amd64") returns "6".
	func ArchChar(goarch string) (string, os.Error) {
	switch goarch {
	case "386":
	return "8", nil
	case "amd64":
	return "6", nil
	case "arm":
	return "5", nil
	}
	return "", os.NewError("unsupported GOARCH " + goarch)
	}

	type build struct {
	script *Script
	path string
	obj string
	goarch string
	arch string
	}

	func (b *build) abs(file string) string {
	if filepath.IsAbs(file) {
	return file
	}
	return filepath.Join(b.path, file)
	}

	func (b *build) abss(file ...string) []string {
	s := make([]string, len(file))
	for i, f := range file {
	s[i] = b.abs(f)
	}
	return s
	}

	func (b *build) add(c Cmd) {
	b.script.Cmd = append(b.script.Cmd, &c)
	}

	func (b *build) mkdir(name string) {
	b.add(Cmd{
	Args: []string{"mkdir", "-p", name},
	Output: []string{name},
	})
	}

	func (b *build) gc(ofile string, gofiles ...string) {
	gc := b.arch + "g"
	args := append([]string{gc, "-o", ofile}, gcImportArgs...)
	args = append(args, gofiles...)
	b.add(Cmd{
	Args: args,
	Input: gofiles,
	Output: []string{ofile},
	})
	}

	func (b *build) asm(ofile string, sfile string) {
	asm := b.arch + "a"
	b.add(Cmd{
	Args: []string{asm, "-o", ofile, sfile},
	Input: []string{sfile},
	Output: []string{ofile},
	})
	}

	func (b *build) ld(targ string, ofiles ...string) {
	ld := b.arch + "l"
	args := append([]string{ld, "-o", targ}, ldImportArgs...)
	args = append(args, ofiles...)
	b.add(Cmd{
	Args: args,
	Input: ofiles,
	Output: []string{targ},
	})
	}

	func (b *build) gopack(targ string, ofiles ...string) {
	b.add(Cmd{
	Args: append([]string{"gopack", "grc", targ}, ofiles...),
	Input: ofiles,
	Output: []string{targ},
	})
	}

	func (b *build) cc(ofile string, cfiles ...string) {
	cc := b.arch + "c"
	dir := fmt.Sprintf("%s_%s", runtime.GOOS, runtime.GOARCH)
	inc := filepath.Join(runtime.GOROOT(), "pkg", dir)
	args := []string{cc, "-FVw", "-I", inc, "-o", ofile}
	b.add(Cmd{
	Args: append(args, cfiles...),
	Input: cfiles,
	Output: []string{ofile},
	})
	}

	func (b *build) gccCompile(ofile, cfile string) {
	b.add(Cmd{
	Args: b.gccArgs("-o", ofile, "-c", cfile),
	Input: []string{cfile},
	Output: []string{ofile},
	})
	}

	func (b *build) gccLink(ofile string, ofiles ...string) {
	b.add(Cmd{
	Args: append(b.gccArgs("-o", ofile), ofiles...),
	Input: ofiles,
	Output: []string{ofile},
	})
	}

	func (b *build) gccArgs(args ...string) []string {
	// TODO(adg): HOST_CC
	a := []string{"gcc", "-I", b.path, "-g", "-fPIC", "-O2"}
	switch b.arch {
	case "8":
	a = append(a, "-m32")
	case "6":
	a = append(a, "-m64")
	}
	return append(a, args...)
	}

	var cgoRe = regexp.MustCompile(`[/\\:]`)

	func (b *build) cgo(cgofiles []string) (outGo, outObj []string) {
	// cgo
	// TODO(adg): CGOPKGPATH
	// TODO(adg): CGO_FLAGS
	gofiles := []string{b.obj + "_cgo_gotypes.go"}
	cfiles := []string{b.obj + "_cgo_main.c", b.obj + "_cgo_export.c"}
	for _, fn := range cgofiles {
	f := b.obj + cgoRe.ReplaceAllString(fn[:len(fn)-2], "_")
	gofiles = append(gofiles, f+"cgo1.go")
	cfiles = append(cfiles, f+"cgo2.c")
	}
	defunC := b.obj + "_cgo_defun.c"
	output := append([]string{defunC}, cfiles...)
	output = append(output, gofiles...)
	b.add(Cmd{
	Args: append([]string{"cgo", "--"}, cgofiles...),
	Dir: b.path,
	Env: append(os.Environ(), "GOARCH="+b.goarch),
	Input: cgofiles,
	Output: output,
	})
	outGo = append(outGo, gofiles...)
	exportH := filepath.Join(b.path, "_cgo_export.h")
	b.script.addIntermediate(defunC, exportH, b.obj+"_cgo_flags")
	b.script.addIntermediate(cfiles...)

	// cc _cgo_defun.c
	defunObj := b.obj + "_cgo_defun." + b.arch
	b.cc(defunObj, defunC)
	outObj = append(outObj, defunObj)

	// gcc
	linkobj := make([]string, 0, len(cfiles))
	for _, cfile := range cfiles {
	ofile := cfile[:len(cfile)-1] + "o"
	b.gccCompile(ofile, cfile)
	linkobj = append(linkobj, ofile)
	if !strings.HasSuffix(ofile, "_cgo_main.o") {
	outObj = append(outObj, ofile)
	} else {
	b.script.addIntermediate(ofile)
	}
	}
	dynObj := b.obj + "_cgo_.o"
	b.gccLink(dynObj, linkobj...)
	b.script.addIntermediate(dynObj)

	// cgo -dynimport
	importC := b.obj + "_cgo_import.c"
	b.add(Cmd{
	Args: []string{"cgo", "-dynimport", dynObj},
	Stdout: importC,
	Input: []string{dynObj},
	Output: []string{importC},
	})
	b.script.addIntermediate(importC)

	// cc _cgo_import.ARCH
	importObj := b.obj + "_cgo_import." + b.arch
	b.cc(importObj, importC)
	outObj = append(outObj, importObj)

	return
	}