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build.go
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build.go
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// 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 main
import (
"bufio"
"bytes"
"container/heap"
"debug/elf"
"errors"
"flag"
"fmt"
"go/build"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
"path"
"path/filepath"
"regexp"
"runtime"
"strconv"
"strings"
"sync"
"time"
)
var cmdBuild = &Command{
UsageLine: "build [-o output] [-i] [build flags] [packages]",
Short: "compile packages and dependencies",
Long: `
Build compiles the packages named by the import paths,
along with their dependencies, but it does not install the results.
If the arguments to build are a list of .go files, build treats
them as a list of source files specifying a single package.
When compiling a single main package, build writes
the resulting executable to an output file named after
the first source file ('go build ed.go rx.go' writes 'ed' or 'ed.exe')
or the source code directory ('go build unix/sam' writes 'sam' or 'sam.exe').
The '.exe' suffix is added when writing a Windows executable.
When compiling multiple packages or a single non-main package,
build compiles the packages but discards the resulting object,
serving only as a check that the packages can be built.
When compiling packages, build ignores files that end in '_test.go'.
The -o flag, only allowed when compiling a single package,
forces build to write the resulting executable or object
to the named output file, instead of the default behavior described
in the last two paragraphs.
The -i flag installs the packages that are dependencies of the target.
The build flags are shared by the build, clean, get, install, list, run,
and test commands:
-a
force rebuilding of packages that are already up-to-date.
-n
print the commands but do not run them.
-p n
the number of programs, such as build commands or
test binaries, that can be run in parallel.
The default is the number of CPUs available.
-race
enable data race detection.
Supported only on linux/amd64, freebsd/amd64, darwin/amd64 and windows/amd64.
-msan
enable interoperation with memory sanitizer.
Supported only on linux/amd64,
and only with Clang/LLVM as the host C compiler.
-v
print the names of packages as they are compiled.
-work
print the name of the temporary work directory and
do not delete it when exiting.
-x
print the commands.
-asmflags 'flag list'
arguments to pass on each go tool asm invocation.
-buildmode mode
build mode to use. See 'go help buildmode' for more.
-compiler name
name of compiler to use, as in runtime.Compiler (gccgo or gc).
-gccgoflags 'arg list'
arguments to pass on each gccgo compiler/linker invocation.
-gcflags 'arg list'
arguments to pass on each go tool compile invocation.
-installsuffix suffix
a suffix to use in the name of the package installation directory,
in order to keep output separate from default builds.
If using the -race flag, the install suffix is automatically set to race
or, if set explicitly, has _race appended to it. Likewise for the -msan
flag. Using a -buildmode option that requires non-default compile flags
has a similar effect.
-ldflags 'flag list'
arguments to pass on each go tool link invocation.
-linkshared
link against shared libraries previously created with
-buildmode=shared.
-pkgdir dir
install and load all packages from dir instead of the usual locations.
For example, when building with a non-standard configuration,
use -pkgdir to keep generated packages in a separate location.
-tags 'tag list'
a list of build tags to consider satisfied during the build.
For more information about build tags, see the description of
build constraints in the documentation for the go/build package.
-toolexec 'cmd args'
a program to use to invoke toolchain programs like vet and asm.
For example, instead of running asm, the go command will run
'cmd args /path/to/asm <arguments for asm>'.
The list flags accept a space-separated list of strings. To embed spaces
in an element in the list, surround it with either single or double quotes.
For more about specifying packages, see 'go help packages'.
For more about where packages and binaries are installed,
run 'go help gopath'.
For more about calling between Go and C/C++, run 'go help c'.
Note: Build adheres to certain conventions such as those described
by 'go help gopath'. Not all projects can follow these conventions,
however. Installations that have their own conventions or that use
a separate software build system may choose to use lower-level
invocations such as 'go tool compile' and 'go tool link' to avoid
some of the overheads and design decisions of the build tool.
See also: go install, go get, go clean.
`,
}
func init() {
// break init cycle
cmdBuild.Run = runBuild
cmdInstall.Run = runInstall
cmdBuild.Flag.BoolVar(&buildI, "i", false, "")
addBuildFlags(cmdBuild)
addBuildFlags(cmdInstall)
}
// Flags set by multiple commands.
var buildA bool // -a flag
var buildN bool // -n flag
var buildP = runtime.NumCPU() // -p flag
var buildV bool // -v flag
var buildX bool // -x flag
var buildI bool // -i flag
var buildO = cmdBuild.Flag.String("o", "", "output file")
var buildWork bool // -work flag
var buildAsmflags []string // -asmflags flag
var buildGcflags []string // -gcflags flag
var buildLdflags []string // -ldflags flag
var buildGccgoflags []string // -gccgoflags flag
var buildRace bool // -race flag
var buildMSan bool // -msan flag
var buildToolExec []string // -toolexec flag
var buildBuildmode string // -buildmode flag
var buildLinkshared bool // -linkshared flag
var buildPkgdir string // -pkgdir flag
var buildContext = build.Default
var buildToolchain toolchain = noToolchain{}
var ldBuildmode string
// buildCompiler implements flag.Var.
// It implements Set by updating both
// buildToolchain and buildContext.Compiler.
type buildCompiler struct{}
func (c buildCompiler) Set(value string) error {
switch value {
case "gc":
buildToolchain = gcToolchain{}
case "gccgo":
buildToolchain = gccgoToolchain{}
default:
return fmt.Errorf("unknown compiler %q", value)
}
buildContext.Compiler = value
return nil
}
func (c buildCompiler) String() string {
return buildContext.Compiler
}
func init() {
switch build.Default.Compiler {
case "gc":
buildToolchain = gcToolchain{}
case "gccgo":
buildToolchain = gccgoToolchain{}
}
}
// addBuildFlags adds the flags common to the build, clean, get,
// install, list, run, and test commands.
func addBuildFlags(cmd *Command) {
cmd.Flag.BoolVar(&buildA, "a", false, "")
cmd.Flag.BoolVar(&buildN, "n", false, "")
cmd.Flag.IntVar(&buildP, "p", buildP, "")
cmd.Flag.BoolVar(&buildV, "v", false, "")
cmd.Flag.BoolVar(&buildX, "x", false, "")
cmd.Flag.Var((*stringsFlag)(&buildAsmflags), "asmflags", "")
cmd.Flag.Var(buildCompiler{}, "compiler", "")
cmd.Flag.StringVar(&buildBuildmode, "buildmode", "default", "")
cmd.Flag.Var((*stringsFlag)(&buildGcflags), "gcflags", "")
cmd.Flag.Var((*stringsFlag)(&buildGccgoflags), "gccgoflags", "")
cmd.Flag.StringVar(&buildContext.InstallSuffix, "installsuffix", "", "")
cmd.Flag.Var((*stringsFlag)(&buildLdflags), "ldflags", "")
cmd.Flag.BoolVar(&buildLinkshared, "linkshared", false, "")
cmd.Flag.StringVar(&buildPkgdir, "pkgdir", "", "")
cmd.Flag.BoolVar(&buildRace, "race", false, "")
cmd.Flag.BoolVar(&buildMSan, "msan", false, "")
cmd.Flag.Var((*stringsFlag)(&buildContext.BuildTags), "tags", "")
cmd.Flag.Var((*stringsFlag)(&buildToolExec), "toolexec", "")
cmd.Flag.BoolVar(&buildWork, "work", false, "")
}
func addBuildFlagsNX(cmd *Command) {
cmd.Flag.BoolVar(&buildN, "n", false, "")
cmd.Flag.BoolVar(&buildX, "x", false, "")
}
func isSpaceByte(c byte) bool {
return c == ' ' || c == '\t' || c == '\n' || c == '\r'
}
// fileExtSplit expects a filename and returns the name
// and ext (without the dot). If the file has no
// extension, ext will be empty.
func fileExtSplit(file string) (name, ext string) {
dotExt := filepath.Ext(file)
name = file[:len(file)-len(dotExt)]
if dotExt != "" {
ext = dotExt[1:]
}
return
}
type stringsFlag []string
func (v *stringsFlag) Set(s string) error {
var err error
*v, err = splitQuotedFields(s)
if *v == nil {
*v = []string{}
}
return err
}
func splitQuotedFields(s string) ([]string, error) {
// Split fields allowing '' or "" around elements.
// Quotes further inside the string do not count.
var f []string
for len(s) > 0 {
for len(s) > 0 && isSpaceByte(s[0]) {
s = s[1:]
}
if len(s) == 0 {
break
}
// Accepted quoted string. No unescaping inside.
if s[0] == '"' || s[0] == '\'' {
quote := s[0]
s = s[1:]
i := 0
for i < len(s) && s[i] != quote {
i++
}
if i >= len(s) {
return nil, fmt.Errorf("unterminated %c string", quote)
}
f = append(f, s[:i])
s = s[i+1:]
continue
}
i := 0
for i < len(s) && !isSpaceByte(s[i]) {
i++
}
f = append(f, s[:i])
s = s[i:]
}
return f, nil
}
func (v *stringsFlag) String() string {
return "<stringsFlag>"
}
func pkgsMain(pkgs []*Package) (res []*Package) {
for _, p := range pkgs {
if p.Name == "main" {
res = append(res, p)
}
}
return res
}
func pkgsNotMain(pkgs []*Package) (res []*Package) {
for _, p := range pkgs {
if p.Name != "main" {
res = append(res, p)
}
}
return res
}
var pkgsFilter = func(pkgs []*Package) []*Package { return pkgs }
func buildModeInit() {
_, gccgo := buildToolchain.(gccgoToolchain)
var codegenArg string
platform := goos + "/" + goarch
switch buildBuildmode {
case "archive":
pkgsFilter = pkgsNotMain
case "c-archive":
pkgsFilter = func(p []*Package) []*Package {
if len(p) != 1 || p[0].Name != "main" {
fatalf("-buildmode=c-archive requires exactly one main package")
}
return p
}
switch platform {
case "darwin/arm", "darwin/arm64":
codegenArg = "-shared"
default:
switch goos {
case "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "solaris":
// Use -shared so that the result is
// suitable for inclusion in a PIE or
// shared library.
codegenArg = "-shared"
}
}
exeSuffix = ".a"
ldBuildmode = "c-archive"
case "c-shared":
pkgsFilter = pkgsMain
if gccgo {
codegenArg = "-fPIC"
} else {
switch platform {
case "linux/amd64", "linux/arm", "linux/arm64", "linux/386",
"android/amd64", "android/arm", "android/arm64", "android/386":
codegenArg = "-shared"
case "darwin/amd64", "darwin/386":
default:
fatalf("-buildmode=c-shared not supported on %s\n", platform)
}
}
ldBuildmode = "c-shared"
case "default":
switch platform {
case "android/arm", "android/arm64", "android/amd64", "android/386":
codegenArg = "-shared"
ldBuildmode = "pie"
case "darwin/arm", "darwin/arm64":
codegenArg = "-shared"
fallthrough
default:
ldBuildmode = "exe"
}
case "exe":
pkgsFilter = pkgsMain
ldBuildmode = "exe"
case "pie":
if gccgo {
fatalf("-buildmode=pie not supported by gccgo")
} else {
switch platform {
case "linux/386", "linux/amd64", "linux/arm", "linux/arm64", "linux/ppc64le", "linux/s390x",
"android/amd64", "android/arm", "android/arm64", "android/386":
codegenArg = "-shared"
default:
fatalf("-buildmode=pie not supported on %s\n", platform)
}
}
ldBuildmode = "pie"
case "shared":
pkgsFilter = pkgsNotMain
if gccgo {
codegenArg = "-fPIC"
} else {
switch platform {
case "linux/386", "linux/amd64", "linux/arm", "linux/arm64", "linux/ppc64le", "linux/s390x":
default:
fatalf("-buildmode=shared not supported on %s\n", platform)
}
codegenArg = "-dynlink"
}
if *buildO != "" {
fatalf("-buildmode=shared and -o not supported together")
}
ldBuildmode = "shared"
case "plugin":
pkgsFilter = pkgsMain
if gccgo {
codegenArg = "-fPIC"
} else {
switch platform {
case "linux/amd64", "linux/arm", "linux/arm64", "linux/386",
"android/amd64", "android/arm", "android/arm64", "android/386":
default:
fatalf("-buildmode=plugin not supported on %s\n", platform)
}
codegenArg = "-dynlink"
}
exeSuffix = ".so"
ldBuildmode = "plugin"
default:
fatalf("buildmode=%s not supported", buildBuildmode)
}
if buildLinkshared {
if gccgo {
codegenArg = "-fPIC"
} else {
switch platform {
case "linux/386", "linux/amd64", "linux/arm", "linux/arm64", "linux/ppc64le", "linux/s390x":
buildAsmflags = append(buildAsmflags, "-D=GOBUILDMODE_shared=1")
default:
fatalf("-linkshared not supported on %s\n", platform)
}
codegenArg = "-dynlink"
// TODO(mwhudson): remove -w when that gets fixed in linker.
buildLdflags = append(buildLdflags, "-linkshared", "-w")
}
}
if codegenArg != "" {
if gccgo {
buildGccgoflags = append(buildGccgoflags, codegenArg)
} else {
buildAsmflags = append(buildAsmflags, codegenArg)
buildGcflags = append(buildGcflags, codegenArg)
}
// Don't alter InstallSuffix when modifying default codegen args.
if buildBuildmode != "default" || buildLinkshared {
if buildContext.InstallSuffix != "" {
buildContext.InstallSuffix += "_"
}
buildContext.InstallSuffix += codegenArg[1:]
}
}
}
func runBuild(cmd *Command, args []string) {
instrumentInit()
buildModeInit()
var b builder
b.init()
pkgs := packagesForBuild(args)
if len(pkgs) == 1 && pkgs[0].Name == "main" && *buildO == "" {
_, *buildO = path.Split(pkgs[0].ImportPath)
*buildO += exeSuffix
}
// Special case -o /dev/null by not writing at all.
if *buildO == os.DevNull {
*buildO = ""
}
// sanity check some often mis-used options
switch buildContext.Compiler {
case "gccgo":
if len(buildGcflags) != 0 {
fmt.Println("go build: when using gccgo toolchain, please pass compiler flags using -gccgoflags, not -gcflags")
}
if len(buildLdflags) != 0 {
fmt.Println("go build: when using gccgo toolchain, please pass linker flags using -gccgoflags, not -ldflags")
}
case "gc":
if len(buildGccgoflags) != 0 {
fmt.Println("go build: when using gc toolchain, please pass compile flags using -gcflags, and linker flags using -ldflags")
}
}
depMode := modeBuild
if buildI {
depMode = modeInstall
}
if *buildO != "" {
if len(pkgs) > 1 {
fatalf("go build: cannot use -o with multiple packages")
} else if len(pkgs) == 0 {
fatalf("no packages to build")
}
p := pkgs[0]
p.target = *buildO
p.Stale = true // must build - not up to date
p.StaleReason = "build -o flag in use"
a := b.action(modeInstall, depMode, p)
b.do(a)
return
}
var a *action
if buildBuildmode == "shared" {
pkgs := pkgsFilter(packages(args))
if libName, err := libname(args, pkgs); err != nil {
fatalf("%s", err.Error())
} else {
a = b.libaction(libName, pkgs, modeBuild, depMode)
}
} else {
a = &action{}
for _, p := range pkgsFilter(packages(args)) {
a.deps = append(a.deps, b.action(modeBuild, depMode, p))
}
}
b.do(a)
}
var cmdInstall = &Command{
UsageLine: "install [build flags] [packages]",
Short: "compile and install packages and dependencies",
Long: `
Install compiles and installs the packages named by the import paths,
along with their dependencies.
For more about the build flags, see 'go help build'.
For more about specifying packages, see 'go help packages'.
See also: go build, go get, go clean.
`,
}
// isMetaPackage checks if name is a reserved package name that expands to multiple packages
func isMetaPackage(name string) bool {
return name == "std" || name == "cmd" || name == "all"
}
// libname returns the filename to use for the shared library when using
// -buildmode=shared. The rules we use are:
// Use arguments for special 'meta' packages:
// std --> libstd.so
// std cmd --> libstd,cmd.so
// A single non-meta argument with trailing "/..." is special cased:
// foo/... --> libfoo.so
// (A relative path like "./..." expands the "." first)
// Use import paths for other cases, changing '/' to '-':
// somelib --> libsubdir-somelib.so
// ./ or ../ --> libsubdir-somelib.so
// gopkg.in/tomb.v2 -> libgopkg.in-tomb.v2.so
// a/... b/... ---> liba/c,b/d.so - all matching import paths
// Name parts are joined with ','.
func libname(args []string, pkgs []*Package) (string, error) {
var libname string
appendName := func(arg string) {
if libname == "" {
libname = arg
} else {
libname += "," + arg
}
}
var haveNonMeta bool
for _, arg := range args {
if isMetaPackage(arg) {
appendName(arg)
} else {
haveNonMeta = true
}
}
if len(libname) == 0 { // non-meta packages only. use import paths
if len(args) == 1 && strings.HasSuffix(args[0], "/...") {
// Special case of "foo/..." as mentioned above.
arg := strings.TrimSuffix(args[0], "/...")
if build.IsLocalImport(arg) {
cwd, _ := os.Getwd()
bp, _ := buildContext.ImportDir(filepath.Join(cwd, arg), build.FindOnly)
if bp.ImportPath != "" && bp.ImportPath != "." {
arg = bp.ImportPath
}
}
appendName(strings.Replace(arg, "/", "-", -1))
} else {
for _, pkg := range pkgs {
appendName(strings.Replace(pkg.ImportPath, "/", "-", -1))
}
}
} else if haveNonMeta { // have both meta package and a non-meta one
return "", errors.New("mixing of meta and non-meta packages is not allowed")
}
// TODO(mwhudson): Needs to change for platforms that use different naming
// conventions...
return "lib" + libname + ".so", nil
}
func runInstall(cmd *Command, args []string) {
installPackages(args, false)
}
func installPackages(args []string, forGet bool) {
if gobin != "" && !filepath.IsAbs(gobin) {
fatalf("cannot install, GOBIN must be an absolute path")
}
instrumentInit()
buildModeInit()
pkgs := pkgsFilter(packagesForBuild(args))
for _, p := range pkgs {
if p.Target == "" && (!p.Standard || p.ImportPath != "unsafe") {
switch {
case p.gobinSubdir:
errorf("go install: cannot install cross-compiled binaries when GOBIN is set")
case p.cmdline:
errorf("go install: no install location for .go files listed on command line (GOBIN not set)")
case p.ConflictDir != "":
errorf("go install: no install location for %s: hidden by %s", p.Dir, p.ConflictDir)
default:
errorf("go install: no install location for directory %s outside GOPATH\n"+
"\tFor more details see: 'go help gopath'", p.Dir)
}
}
}
exitIfErrors()
var b builder
b.init()
// Set the behavior for `go get` to not error on packages with test files only.
b.testFilesOnlyOK = forGet
var a *action
if buildBuildmode == "shared" {
if libName, err := libname(args, pkgs); err != nil {
fatalf("%s", err.Error())
} else {
a = b.libaction(libName, pkgs, modeInstall, modeInstall)
}
} else {
a = &action{}
var tools []*action
for _, p := range pkgs {
// If p is a tool, delay the installation until the end of the build.
// This avoids installing assemblers/compilers that are being executed
// by other steps in the build.
// cmd/cgo is handled specially in b.action, so that we can
// both build and use it in the same 'go install'.
action := b.action(modeInstall, modeInstall, p)
if goTools[p.ImportPath] == toTool && p.ImportPath != "cmd/cgo" {
a.deps = append(a.deps, action.deps...)
action.deps = append(action.deps, a)
tools = append(tools, action)
continue
}
a.deps = append(a.deps, action)
}
if len(tools) > 0 {
a = &action{
deps: tools,
}
}
}
b.do(a)
exitIfErrors()
// Success. If this command is 'go install' with no arguments
// and the current directory (the implicit argument) is a command,
// remove any leftover command binary from a previous 'go build'.
// The binary is installed; it's not needed here anymore.
// And worse it might be a stale copy, which you don't want to find
// instead of the installed one if $PATH contains dot.
// One way to view this behavior is that it is as if 'go install' first
// runs 'go build' and the moves the generated file to the install dir.
// See issue 9645.
if len(args) == 0 && len(pkgs) == 1 && pkgs[0].Name == "main" {
// Compute file 'go build' would have created.
// If it exists and is an executable file, remove it.
_, targ := filepath.Split(pkgs[0].ImportPath)
targ += exeSuffix
if filepath.Join(pkgs[0].Dir, targ) != pkgs[0].Target { // maybe $GOBIN is the current directory
fi, err := os.Stat(targ)
if err == nil {
m := fi.Mode()
if m.IsRegular() {
if m&0111 != 0 || goos == "windows" { // windows never sets executable bit
os.Remove(targ)
}
}
}
}
}
}
// Global build parameters (used during package load)
var (
goarch string
goos string
exeSuffix string
gopath []string
)
func init() {
goarch = buildContext.GOARCH
goos = buildContext.GOOS
if goos == "windows" {
exeSuffix = ".exe"
}
gopath = filepath.SplitList(buildContext.GOPATH)
}
// A builder holds global state about a build.
// It does not hold per-package state, because we
// build packages in parallel, and the builder is shared.
type builder struct {
work string // the temporary work directory (ends in filepath.Separator)
actionCache map[cacheKey]*action // a cache of already-constructed actions
mkdirCache map[string]bool // a cache of created directories
flagCache map[string]bool // a cache of supported compiler flags
print func(args ...interface{}) (int, error)
testFilesOnlyOK bool // do not error if the packages only have test files
output sync.Mutex
scriptDir string // current directory in printed script
exec sync.Mutex
readySema chan bool
ready actionQueue
}
// An action represents a single action in the action graph.
type action struct {
p *Package // the package this action works on
deps []*action // actions that must happen before this one
triggers []*action // inverse of deps
cgo *action // action for cgo binary if needed
args []string // additional args for runProgram
testOutput *bytes.Buffer // test output buffer
f func(*builder, *action) error // the action itself (nil = no-op)
ignoreFail bool // whether to run f even if dependencies fail
// Generated files, directories.
link bool // target is executable, not just package
pkgdir string // the -I or -L argument to use when importing this package
objdir string // directory for intermediate objects
objpkg string // the intermediate package .a file created during the action
target string // goal of the action: the created package or executable
// Execution state.
pending int // number of deps yet to complete
priority int // relative execution priority
failed bool // whether the action failed
}
// cacheKey is the key for the action cache.
type cacheKey struct {
mode buildMode
p *Package
shlib string
}
// buildMode specifies the build mode:
// are we just building things or also installing the results?
type buildMode int
const (
modeBuild buildMode = iota
modeInstall
)
var (
goroot = filepath.Clean(runtime.GOROOT())
gobin = os.Getenv("GOBIN")
gorootBin = filepath.Join(goroot, "bin")
gorootPkg = filepath.Join(goroot, "pkg")
gorootSrc = filepath.Join(goroot, "src")
)
func (b *builder) init() {
var err error
b.print = func(a ...interface{}) (int, error) {
return fmt.Fprint(os.Stderr, a...)
}
b.actionCache = make(map[cacheKey]*action)
b.mkdirCache = make(map[string]bool)
if buildN {
b.work = "$WORK"
} else {
b.work, err = ioutil.TempDir("", "go-build")
if err != nil {
fatalf("%s", err)
}
if buildX || buildWork {
fmt.Fprintf(os.Stderr, "WORK=%s\n", b.work)
}
if !buildWork {
workdir := b.work
atexit(func() { os.RemoveAll(workdir) })
}
}
}
// goFilesPackage creates a package for building a collection of Go files
// (typically named on the command line). The target is named p.a for
// package p or named after the first Go file for package main.
func goFilesPackage(gofiles []string) *Package {
// TODO: Remove this restriction.
for _, f := range gofiles {
if !strings.HasSuffix(f, ".go") {
fatalf("named files must be .go files")
}
}
var stk importStack
ctxt := buildContext
ctxt.UseAllFiles = true
// Synthesize fake "directory" that only shows the named files,
// to make it look like this is a standard package or
// command directory. So that local imports resolve
// consistently, the files must all be in the same directory.
var dirent []os.FileInfo
var dir string
for _, file := range gofiles {
fi, err := os.Stat(file)
if err != nil {
fatalf("%s", err)
}
if fi.IsDir() {
fatalf("%s is a directory, should be a Go file", file)
}
dir1, _ := filepath.Split(file)
if dir1 == "" {
dir1 = "./"
}
if dir == "" {
dir = dir1
} else if dir != dir1 {
fatalf("named files must all be in one directory; have %s and %s", dir, dir1)
}
dirent = append(dirent, fi)
}
ctxt.ReadDir = func(string) ([]os.FileInfo, error) { return dirent, nil }
var err error
if dir == "" {
dir = cwd
}
dir, err = filepath.Abs(dir)
if err != nil {
fatalf("%s", err)
}
bp, err := ctxt.ImportDir(dir, 0)
pkg := new(Package)
pkg.local = true
pkg.cmdline = true
stk.push("main")
pkg.load(&stk, bp, err)
stk.pop()
pkg.localPrefix = dirToImportPath(dir)
pkg.ImportPath = "command-line-arguments"
pkg.target = ""
if pkg.Name == "main" {
_, elem := filepath.Split(gofiles[0])
exe := elem[:len(elem)-len(".go")] + exeSuffix
if *buildO == "" {
*buildO = exe
}
if gobin != "" {
pkg.target = filepath.Join(gobin, exe)
}
}
pkg.Target = pkg.target
pkg.Stale = true
pkg.StaleReason = "files named on command line"
computeStale(pkg)
return pkg
}
// readpkglist returns the list of packages that were built into the shared library
// at shlibpath. For the native toolchain this list is stored, newline separated, in
// an ELF note with name "Go\x00\x00" and type 1. For GCCGO it is extracted from the
// .go_export section.
func readpkglist(shlibpath string) (pkgs []*Package) {
var stk importStack
if _, gccgo := buildToolchain.(gccgoToolchain); gccgo {
f, _ := elf.Open(shlibpath)
sect := f.Section(".go_export")
data, _ := sect.Data()
scanner := bufio.NewScanner(bytes.NewBuffer(data))
for scanner.Scan() {
t := scanner.Text()
if strings.HasPrefix(t, "pkgpath ") {
t = strings.TrimPrefix(t, "pkgpath ")
t = strings.TrimSuffix(t, ";")
pkgs = append(pkgs, loadPackage(t, &stk))
}
}
} else {
pkglistbytes, err := readELFNote(shlibpath, "Go\x00\x00", 1)
if err != nil {
fatalf("readELFNote failed: %v", err)
}
scanner := bufio.NewScanner(bytes.NewBuffer(pkglistbytes))
for scanner.Scan() {
t := scanner.Text()
pkgs = append(pkgs, loadPackage(t, &stk))
}
}
return
}
// action returns the action for applying the given operation (mode) to the package.
// depMode is the action to use when building dependencies.
// action never looks for p in a shared library, but may find p's dependencies in a
// shared library if buildLinkshared is true.
func (b *builder) action(mode buildMode, depMode buildMode, p *Package) *action {
return b.action1(mode, depMode, p, false, "")
}
// action1 returns the action for applying the given operation (mode) to the package.
// depMode is the action to use when building dependencies.
// action1 will look for p in a shared library if lookshared is true.
// forShlib is the shared library that p will become part of, if any.
func (b *builder) action1(mode buildMode, depMode buildMode, p *Package, lookshared bool, forShlib string) *action {
shlib := ""
if lookshared {
shlib = p.Shlib
}
key := cacheKey{mode, p, shlib}
a := b.actionCache[key]
if a != nil {
return a
}
if shlib != "" {
key2 := cacheKey{modeInstall, nil, shlib}
a = b.actionCache[key2]
if a != nil {
b.actionCache[key] = a
return a
}
pkgs := readpkglist(shlib)
a = b.libaction(filepath.Base(shlib), pkgs, modeInstall, depMode)
b.actionCache[key2] = a
b.actionCache[key] = a
return a
}
a = &action{p: p, pkgdir: p.build.PkgRoot}
if p.pkgdir != "" { // overrides p.t
a.pkgdir = p.pkgdir
}
b.actionCache[key] = a
for _, p1 := range p.imports {
if forShlib != "" {
// p is part of a shared library.
if p1.Shlib != "" && p1.Shlib != forShlib {
// p1 is explicitly part of a different shared library.
// Put the action for that shared library into a.deps.
a.deps = append(a.deps, b.action1(depMode, depMode, p1, true, p1.Shlib))
} else {
// p1 is (implicitly or not) part of this shared library.
// Put the action for p1 into a.deps.
a.deps = append(a.deps, b.action1(depMode, depMode, p1, false, forShlib))
}
} else {
// p is not part of a shared library.
// If p1 is in a shared library, put the action for that into
// a.deps, otherwise put the action for p1 into a.deps.
a.deps = append(a.deps, b.action1(depMode, depMode, p1, buildLinkshared, p1.Shlib))
}
}
// If we are not doing a cross-build, then record the binary we'll
// generate for cgo as a dependency of the build of any package
// using cgo, to make sure we do not overwrite the binary while
// a package is using it. If this is a cross-build, then the cgo we
// are writing is not the cgo we need to use.
if goos == runtime.GOOS && goarch == runtime.GOARCH && !buildRace && !buildMSan {
if (len(p.CgoFiles) > 0 || p.Standard && p.ImportPath == "runtime/cgo") && !buildLinkshared && buildBuildmode != "shared" {
var stk importStack
p1 := loadPackage("cmd/cgo", &stk)
if p1.Error != nil {
fatalf("load cmd/cgo: %v", p1.Error)
}