obj := pathf("%s/pkg/obj", goroot)
	if !isdir(obj) {
		xmkdir(obj)
	}
	xatexit(func() { xremove(obj) })

	// Create build cache directory.
	objGobuild := pathf("%s/pkg/obj/go-build", goroot)
	if rebuildall {
		xremoveall(objGobuild)
	}
	xmkdirall(objGobuild)
	xatexit(func() { xremoveall(objGobuild) })

	// Create directory for bootstrap versions of standard library .a files.

	// 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.

	if strings.HasPrefix(os.Getenv("GO_BUILDER_NAME"), "linux-") {
		if os.Getuid() == 0 {
			// Don't bother making GOROOT unwritable:
			// we're running as root, so permissions would have no effect.
		} else {
			xatexit(t.makeGOROOTUnwritable())
		}
	}

	if !t.json {
		if err := t.maybeLogMetadata(); err != nil {
			t.failed = true
			if t.keepGoing {
				log.Printf("Failed logging metadata: %v", err)
			} else {

var memprofilerateflag = flag.Int("memprofilerate", 0, "Set memprofile sampling rate to value")

var matchpkg func(name string) bool

var atExitFuncs []func()

func atExit(f func()) {
	atExitFuncs = append(atExitFuncs, f)
}

func Exit(code int) {
	for i := len(atExitFuncs) - 1; i >= 0; i-- {
		f := atExitFuncs[i]
		atExitFuncs = atExitFuncs[:i]
		f()
	}
	os.Exit(code)
}

			expected string
			musthave []string
		}{
			{
				mode:     "simple",
				expected: "bar foo",
			},
			{
				mode:     "goodexit",
				expected: "orange apple",
			},
			{
				mode:     "badexit",
				expected: "blub blix",
			},
			{
				mode: "panics",
				musthave: []string{
					"fatal error: exit hook invoked panic",
					"main.testPanics",
				},
			},
			{
				mode: "callsexit",

	if ctxt.Debugvlog > 0 {
		// dump symbol info on crash
		defer func() { ctxt.loader.Dump() }()
	}
	if ctxt.Debugvlog > 1 {
		// dump symbol info on error
		AtExit(func() {
			if nerrors > 0 {
				ctxt.loader.Dump()
			}
		})
	}

	switch *flagHeadType {
	case "":
	case "windowsgui":
		ctxt.HeadType = objabi.Hwindows
		windowsgui = true
	default:

	_ "unsafe"
)

var modeflag = flag.String("mode", "", "mode to run in")

func main() {
	flag.Parse()
	switch *modeflag {
	case "simple":
		testSimple()
	case "goodexit":
		testGoodExit()
	case "badexit":
		testBadExit()
	case "panics":
		testPanics()
	case "callsexit":
		testHookCallsExit()
	case "exit2":
		testExit2()
	default:
		panic("unknown mode")
	}
}

func testSimple() {

// it is a documentation pseudo-command such as importpath.
func (c *Command) Runnable() bool {
	return c.Run != nil
}

var atExitFuncs []func()

func AtExit(f func()) {
	atExitFuncs = append(atExitFuncs, f)
}

func Exit() {
	for _, f := range atExitFuncs {
		f()
	}
	os.Exit(exitStatus)
}

func Fatalf(format string, args ...any) {

	base        reflect.Type // the base type after all indirections
	indir       int          // number of indirections to reach the base type
	externalEnc int          // xGob, xBinary, or xText
	externalDec int          // xGob, xBinary, or xText
	encIndir    int8         // number of indirections to reach the receiver type; may be negative
	decIndir    int8         // number of indirections to reach the receiver type; may be negative
}

	if cfg.DebugTrace == "" {
		return pctx
	}

	ctx, close, err := trace.Start(pctx, cfg.DebugTrace)
	if err != nil {
		base.Fatalf("failed to start trace: %v", err)
	}
	base.AtExit(func() {
		if err := close(); err != nil {
			base.Fatalf("failed to stop trace: %v", err)
		}
	})

	return ctx
}

// handleChdirFlag handles the -C flag before doing anything else.