if vers >= 5 {
			u.utype = b.uint8()
			u.asize = int(b.uint8())
		}
		var abbrevOff uint64
		if u.is64 {
			abbrevOff = b.uint64()
		} else {
			abbrevOff = uint64(b.uint32())
		}
		atable, err := d.parseAbbrev(abbrevOff, u.vers)
		if err != nil {
			if b.err == nil {
				b.err = err
			}
			break
		}
		u.atable = atable
		if vers < 5 {
			u.asize = int(b.uint8())
		}

		switch u.utype {

			b.error("unsupported DWARF version " + strconv.Itoa(vers))
			return b.err
		}
		var ao uint64
		if !dwarf64 {
			ao = uint64(b.uint32())
		} else {
			ao = b.uint64()
		}
		atable, err := d.parseAbbrev(ao, vers)
		if err != nil {
			return err
		}
		asize := b.uint8()
		sig := b.uint64()

		var toff uint32
		if !dwarf64 {
			toff = b.uint32()
		} else {
			to64 := b.uint64()

	class Class
	val   int64 // for formImplicitConst
}

// a map from entry format ids to their descriptions
type abbrevTable map[uint32]abbrev

// parseAbbrev returns the abbreviation table that starts at byte off
// in the .debug_abbrev section.
func (d *Data) parseAbbrev(off uint64, vers int) (abbrevTable, error) {
	if m, ok := d.abbrevCache[off]; ok {
		return m, nil
	}

	data := d.abbrev
	if off > uint64(len(data)) {