t.Fatalf("unable to write previously parsed content: %s", err)
			}
		}

		if err := w.Close(); err != nil {
			t.Fatalf("Unable to write archive: %s", err)
		}

		// TODO: We may want to check if the archive roundtrips.
	})

To install:

1) chrome://extensions/
2) click "[+] Developer Mode" in top right
3) "Load unpacked extension..."
4) pick $GOROOT/misc/chrome/gophertool

	if err != nil {
		t.Fatal(err)
	}
	fis, err := td.Readdir(0)
	if err != nil {
		t.Fatal(err)
	}
	for _, fi := range fis {
		if !fi.IsDir() {
			continue
		}

		// TODO(gri) remove extra pkg directory eventually
		goldenFile := filepath.Join("testdata", "src", "pkg", fi.Name(), "golden.txt")
		w := NewWalker(nil, "testdata/src/pkg")
		pkg, _ := w.import_(fi.Name())
		w.export(pkg)

			if len(d) < 12 {
				t.Logf("note section %d too short (%d < 12)", i, len(d))
				continue sections
			}

			namesz := f.ByteOrder.Uint32(d)
			descsz := f.ByteOrder.Uint32(d[4:])
			typ := f.ByteOrder.Uint32(d[8:])

			an := (namesz + 3) &^ 3
			ad := (descsz + 3) &^ 3

			if int(12+an+ad) > len(d) {

				t.Fatalf("unable to write previously parsed content: %s", err)
			}
		}
		if err := w.Close(); err != nil {
			t.Fatalf("Unable to write archive: %s", err)
		}

		// TODO: We may want to check if the archive roundtrips. This would require
		// taking into account addition of the two zero trailer blocks that Writer.Close
		// appends.
	})

	f.Close()
	if err != nil {
		log.Fatal(err)
	}

	// <= go 1.7 doesn't embed the contentID or actionID, so no slash is present
	if !strings.Contains(id, "/") {
		log.Fatalf("%s: build ID is a legacy format...binary too old for this tool", file)
	}

	newID := id[:strings.LastIndex(id, "/")] + "/" + buildid.HashToString(hash)
	if len(newID) != len(id) {
		log.Fatalf("%s: build ID length mismatch %q vs %q", file, id, newID)
	}

	SRLIW	$-1, X5, X6			// ERROR "immediate out of range 0 to 31"
	SRAIW	$-1, X5, X6			// ERROR "immediate out of range 0 to 31"
	SD	X5, 4294967296(X6)		// ERROR "constant 4294967296 too large"
	SRLI	$1, X5, F1			// ERROR "expected integer register in rd position but got non-integer register F1"
	SRLI	$1, F1, X5			// ERROR "expected integer register in rs1 position but got non-integer register F1"

	MOVQ 2147483647+1(AX), AX       // ERROR "offset too large"
	MOVQ 3395469782(R10), R8        // ERROR "offset too large"
	LEAQ 3395469782(AX), AX         // ERROR "offset too large"
	ADDQ 3395469782(AX), AX         // ERROR "offset too large"
	ADDL 3395469782(AX), AX         // ERROR "offset too large"
	ADDW 3395469782(AX), AX         // ERROR "offset too large"
	LEAQ 433954697820(AX), AX       // ERROR "offset too large"

	JCS	2(PC)
	JMP	*4(SP) // JMP 4(SP)
	JCS	2(PC)
	JMP	*(R12) // JMP (R12)
	JCS	2(PC)
//	JMP	*(R12*4) // TODO: This line is silently dropped on the floor!
	JCS	2(PC)
	JMP	*(R12)(R13*4) // JMP (R12)(R13*4)
	JCS	2(PC)
	JMP	*(AX) // JMP (AX)
	JCS	2(PC)
	JMP	*(SP) // JMP (SP)
	JCS	2(PC)
//	JMP	*(AX*4) // TODO: This line is silently dropped on the floor!
	JCS	2(PC)
	JMP	*(AX)(AX*4) // JMP (AX)(AX*4)
	JCS	2(PC)
	JMP	4(SP)

	tw := tar.NewWriter(&buf)
	var files = []struct {
		Name, Body string
	}{
		{"readme.txt", "This archive contains some text files."},
		{"gopher.txt", "Gopher names:\nGeorge\nGeoffrey\nGonzo"},
		{"todo.txt", "Get animal handling license."},
	}
	for _, file := range files {
		hdr := &tar.Header{
			Name: file.Name,
			Mode: 0600,
			Size: int64(len(file.Body)),
		}
		if err := tw.WriteHeader(hdr); err != nil {