off := int64(len(armag))
	for {
		var hdrBuf [arHdrSize]byte
		if _, err := archive.Read(hdrBuf[:]); err != nil {
			return nil, err
		}
		off += arHdrSize

		if !bytes.Equal(hdrBuf[arFmagOff:arFmagOff+arFmagSize], []byte(arfmag)) {
			return nil, fmt.Errorf("archive header format header (%q)", hdrBuf[:])
		}

		size, err := strconv.ParseInt(strings.TrimSpace(string(hdrBuf[arSizeOff:arSizeOff+arSizeSize])), 10, 64)

	b := makeBuf(d, unknownFormat{}, name, 0, types)
	for len(b.data) > 0 {
		base := b.off
		n, dwarf64 := b.unitLength()
		if n != Offset(uint32(n)) {
			b.error("type unit length overflow")
			return b.err
		}
		hdroff := b.off
		vers := int(b.uint16())
		if vers != 4 {
			b.error("unsupported DWARF version " + strconv.Itoa(vers))
			return b.err
		}
		var ao uint64
		if !dwarf64 {
			ao = uint64(b.uint32())
		} else {