type Arch struct {
	*obj.LinkArch
	// Map of instruction names to enumeration.
	Instructions map[string]obj.As
	// Map of register names to enumeration.
	Register map[string]int16
	// Table of register prefix names. These are things like R for R(0) and SPR for SPR(268).
	RegisterPrefix map[string]bool
	// RegisterNumber converts R(10) into arm.REG_R10.

	fmt.Fprintf(&buf, "\n")

	override := make(map[string]string)

	// Allow source file to specify override mappings.
	// For example, the socket data structures refer
	// to in_addr and in_addr6 structs but we want to be
	// able to treat them as byte arrays, so the godefs
	// inputs in package syscall say
	//
	//	// +godefs map struct_in_addr [4]byte
	//	// +godefs map struct_in_addr6 [16]byte
	//

}

var (
	mu          sync.Mutex
	crawled     = make(map[string]bool)      // URL without fragment -> true
	neededFrags = make(map[urlFrag][]string) // URL#frag -> who needs it
)

var aRx = regexp.MustCompile(`<a href=['"]?(/[^\s'">]+)`)

// Owned by crawlLoop goroutine:
var (
	linkSources = make(map[string][]string) // url no fragment -> sources
	fragExists  = make(map[urlFrag]bool)
	problems    []string
)

	addr2lineExePath  string
	addr2linePathErr  error
)

func loadSyms(t *testing.T, dbgExePath string) map[string]string {
	cmd := testenv.Command(t, testenv.GoToolPath(t), "tool", "nm", dbgExePath)
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("%v: %v\n%s", cmd, err, string(out))
	}
	syms := make(map[string]string)
	scanner := bufio.NewScanner(bytes.NewReader(out))
	for scanner.Scan() {

	r.fileListOnce.Do(func() {
		// files and knownDirs map from a file/directory name
		// to an index into the r.fileList entry that we are
		// building. They are used to mark duplicate entries.
		files := make(map[string]int)
		knownDirs := make(map[string]int)

		// dirs[name] is true if name is known to be a directory,
		// because it appears as a prefix in a path.
		dirs := make(map[string]bool)

		for _, file := range r.File {

	log.SetFlags(0)
	flag.Usage = usage
	flag.Parse()
	args := flag.Args()
	if len(args) != 1 || !strings.HasSuffix(args[0], ".zip") {
		usage()
	}

	var zb bytes.Buffer
	zw := zip.NewWriter(&zb)
	seen := make(map[string]bool)
	err := filepath.WalkDir(".", func(path string, d fs.DirEntry, err error) error {
		if d.IsDir() {
			return nil
		}
		data, err := os.ReadFile(path)
		if err != nil {
			log.Fatal(err)
		}

	// own keys and assigning certain semantic meaning to the associated values.
	// For example, sparse file support in PAX is implemented using keys
	// defined by the GNU manual (e.g., "GNU.sparse.map").
	//
	// Reference:
	//	http://pubs.opengroup.org/onlinepubs/009695399/utilities/pax.html
	FormatPAX

	// FormatGNU represents the GNU header format.
	//

	// 1.  Grow. This triggers two reallocations in Map.
	maxRune := func(r rune) rune { return unicode.MaxRune }
	m := Map(maxRune, []byte(a))
	expect := tenRunes(unicode.MaxRune)
	if string(m) != expect {
		t.Errorf("growing: expected %q got %q", expect, m)
	}

	// 2. Shrink
	minRune := func(r rune) rune { return 'a' }
	m = Map(minRune, []byte(tenRunes(unicode.MaxRune)))
	expect = a

	rot13 := func(r rune) rune {
		switch {
		case r >= 'A' && r <= 'Z':
			return 'A' + (r-'A'+13)%26
		case r >= 'a' && r <= 'z':
			return 'a' + (r-'a'+13)%26
		}
		return r
	}
	fmt.Printf("%s\n", bytes.Map(rot13, []byte("'Twas brillig and the slithy gopher...")))
	// Output:
	// 'Gjnf oevyyvt naq gur fyvgul tbcure...
}

func ExampleReader_Len() {
	fmt.Println(bytes.NewReader([]byte("Hi!")).Len())

// (m[key]) from the map. If m is nil or there is no such element, delete
// is a no-op.
func delete(m map[Type]Type1, key Type)

// The len built-in function returns the length of v, according to its type:
//
//	Array: the number of elements in v.
//	Pointer to array: the number of elements in *v (even if v is nil).
//	Slice, or map: the number of elements in v; if v is nil, len(v) is zero.