}

// GetBuildID returns the GNU build-ID for an ELF binary.
//
// If no build-ID was found but the binary was read without error, it returns
// (nil, nil).
func GetBuildID(f *elf.File) ([]byte, error) {
	findBuildID := func(notes []elfNote) ([]byte, error) {
		var buildID []byte
		for _, note := range notes {
			if note.Name == "GNU" && note.Type == noteTypeGNUBuildID {
				if buildID == nil {
					buildID = note.Desc

	goTool := testenv.GoToolPath(t)

	cmd := testenv.Command(t, goTool, "build", "-o", outFile, "-ldflags", "-buildid 0x1234 -B gobuildid", goFile)
	cmd.Dir = t.TempDir()

	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Logf("%s", out)
		t.Fatal(err)
	}

	expectedGoBuildID := notsha256.Sum256([]byte("0x1234"))

	gnuBuildID, err := buildid.ReadELFNote(outFile, string(ld.ELF_NOTE_BUILDINFO_NAME), ld.ELF_NOTE_BUILDINFO_TAG)

### `gradle` value

This value, nested in `createdBy`, must contain an object with the following values:

- `version`: The version of Gradle. A string
- `buildId`: The buildId for the Gradle instance. A string

### `variants` value

This value must contain an array with zero or more elements. Each element must be an object with the following values:

	size = size - (size % mapsizeRounding)
	key := mappingKey{
		size:   size,
		offset: m.Offset,
	}

	switch {
	case m.BuildID != "":
		key.buildIDOrFile = m.BuildID
	case m.File != "":
		key.buildIDOrFile = m.File
	default:
		// A mapping containing neither build ID nor file name is a fake mapping. A
		// key with empty buildIDOrFile is used for fake mappings so that they are

		ldflags = str.StringList("-Wl,-(", ldflags, "-Wl,-)")
	}

	if root.buildID != "" {
		// On systems that normally use gold or the GNU linker,
		// use the --build-id option to write a GNU build ID note.
		switch cfg.Goos {
		case "android", "dragonfly", "linux", "netbsd":
			ldflags = append(ldflags, fmt.Sprintf("-Wl,--build-id=0x%x", root.buildID))
		}
	}

	var rLibPath string
	if cfg.Goos == "aix" {

### `gradle` value

This value, nested in `createdBy`, must contain an object with the following values:

- `version`: The version of Gradle. A string
- `buildId`: optional. The buildId for the Gradle instance. A string

### `variants` value

This value must contain an array with zero or more elements. Each element must be an object with the following values:

        writeTo(writer, publication, [publication])
        def buildIdContent = ""
        if (withBuildId) {
            buildIdContent = """,
      "buildId": "${buildId}\""""
        }

        then:
        writer.toString() == """{
  "formatVersion": "${GradleModuleMetadataParser.FORMAT_VERSION}",
  "component": {
    "group": "group",
    "module": "module",

    def fingerprinterRegistry = Stub(FileCollectionFingerprinterRegistry) {
        getFingerprinter(_) >> fingerprinter
    }
    def executionHistoryStore = Mock(ExecutionHistoryStore)
    def buildId = UniqueId.generate()

    def actionListener = Stub(TaskActionListener)
    def outputChangeListener = Stub(OutputChangeListener)
    def changeDetector = new DefaultExecutionStateChangeDetector()

	// go tool yet forms part of our command-line interface.
	// TODO(adonovan): clarify the contract.

	// Print the tool version so the build system can track changes.
	// Formats:
	//   $progname version devel ... buildID=...
	//   $progname version go1.9.1
	progname, err := os.Executable()
	if err != nil {
		return err
	}
	f, err := os.Open(progname)
	if err != nil {

		for _, l := range s.Location {
			s.locationIDX = append(s.locationIDX, l.ID)
		}
	}

	for _, m := range p.Mapping {
		m.fileX = addString(strings, m.File)
		m.buildIDX = addString(strings, m.BuildID)
	}

	for _, l := range p.Location {
		for i, ln := range l.Line {
			if ln.Function != nil {
				l.Line[i].functionIDX = ln.Function.ID
			} else {
				l.Line[i].functionIDX = 0
			}
		}