}

	// As of 2018-07-17, lldb doesn't support compressed DWARF, so
	// disable it for this test.
	cmd := exec.Command(testenv.GoToolPath(t), "build", "-gcflags=all=-N -l", "-ldflags=-compressdwarf=false", "-o", "a.exe")
	cmd.Dir = dir
	cmd.Env = append(os.Environ(), "GOPATH=") // issue 31100
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("building source %v\n%s", err, out)
	}

		Mark a dynamically linked ELF object for immediate function binding (default false).
	-buildid id
		Record id as Go toolchain build id.
	-buildmode mode
		Set build mode (default exe).
	-c
		Dump call graphs.
	-compressdwarf
		Compress DWARF if possible (default true).
	-cpuprofile file
		Write CPU profile to file.
	-d
		Disable generation of dynamic executables.
		The emitted code is the same in either case; the option

	Out    *OutBuf

	version int // current version number for static/file-local symbols

	Debugvlog int
	Bso       *bufio.Writer

	Loaded bool // set after all inputs have been loaded as symbols

	compressDWARF bool

	Libdir       []string
	Library      []*sym.Library
	LibraryByPkg map[string]*sym.Library
	Shlibs       []Shlib
	Textp        []loader.Sym
	Moduledata   loader.Sym

	PackageFile  map[string]string

	flag.Var(&ctxt.LinkMode, "linkmode", "set link `mode`")
	flag.Var(&ctxt.BuildMode, "buildmode", "set build `mode`")
	flag.BoolVar(&ctxt.compressDWARF, "compressdwarf", true, "compress DWARF if possible")
	objabi.Flagfn1("B", "add an ELF NT_GNU_BUILD_ID `note` when using ELF; use \"gobuildid\" to generate it from the Go build ID", addbuildinfo)

// weren't compressed, or an error if there was a problem reading dwarfm.
func machoCompressSections(ctxt *Link, dwarfm *macho.File) ([]*macho.Section, []byte, error) {
	if !ctxt.compressDWARF {
		return nil, nil, nil
	}

	dwarfseg := dwarfm.Segment("__DWARF")
	var sects []*macho.Section
	var buf bytes.Buffer

	for _, sect := range dwarfm.Sections {
		if sect.Seg != "__DWARF" {

		if linkerFlagSupported(ctxt.Arch, argv[0], altLinker, noTimeStamp) {
			argv = append(argv, noTimeStamp)
		}
	}

	const compressDWARF = "-Wl,--compress-debug-sections=zlib"
	if ctxt.compressDWARF && linkerFlagSupported(ctxt.Arch, argv[0], altLinker, compressDWARF) {
		argv = append(argv, compressDWARF)
	}

	hostObjCopyPaths := ctxt.hostobjCopy()
	cleanTimeStamps(hostObjCopyPaths)

	moreargs := []string{}
	if *useGdb && (runtime.GOOS == "darwin" || runtime.GOOS == "windows") {
		// gdb and lldb on Darwin do not deal with compressed dwarf.
		// also, Windows.
		moreargs = append(moreargs, "-ldflags=-compressdwarf=false")
	}

	subTest(t, debugger+"-dbg", "hist", dbgFlags, moreargs...)
	subTest(t, debugger+"-dbg", "scopes", dbgFlags, moreargs...)
	subTest(t, debugger+"-dbg", "i22558", dbgFlags, moreargs...)

	type compressedSect struct {
		index      int
		compressed []byte
		syms       []loader.Sym
	}

	supported := ctxt.IsELF || ctxt.IsWindows() || ctxt.IsDarwin()
	if !ctxt.compressDWARF || !supported || ctxt.IsExternal() {
		return
	}

	var compressedCount int
	resChannel := make(chan compressedSect)
	for i := range dwarfp {
		go func(resIndex int, syms []loader.Sym) {