if err != nil {
				Exitf("cannot reopen %s: %v", h.pn, err)
			}
			defer f.Close()
			if _, err := f.Seek(h.off, 0); err != nil {
				Exitf("cannot seek %s: %v", h.pn, err)
			}

			w, err := os.Create(dst)
			if err != nil {
				Exitf("cannot create %s: %v", dst, err)
			}
			if _, err := io.CopyN(w, f, h.length); err != nil {
				Exitf("cannot write %s: %v", dst, err)
			}

	if hex.DecodedLen(len(val)) > maxLen {
		Exitf("-B option too long (max %d digits): %s", maxLen, ov)
	}

	b, err := hex.DecodeString(val)
	if err != nil {
		if err == hex.ErrLength {
			Exitf("-B argument must have even number of digits: %s", ov)
		}
		if inv, ok := err.(hex.InvalidByteError); ok {
			Exitf("-B argument contains invalid hex digit %c: %s", byte(inv), ov)
		}
		Exitf("-B argument contains invalid hex: %s", ov)

}

// xcoffGetDwarfSubtype returns the XCOFF name of the DWARF section str
// and its subtype constant.
func xcoffGetDwarfSubtype(str string) (string, uint32) {
	switch str {
	default:
		Exitf("unknown DWARF section name for XCOFF: %s", str)
	case ".debug_abbrev":
		return ".dwabrev", SSUBTYP_DWABREV
	case ".debug_info":
		return ".dwinfo", SSUBTYP_DWINFO
	case ".debug_frame":

}

func (d *dwctxt) lookupOrDiag(n string) loader.Sym {
	symIdx := d.ldr.Lookup(n, 0)
	if symIdx == 0 {
		Exitf("dwarf: missing type: %s", n)
	}
	if len(d.ldr.Data(symIdx)) == 0 {
		Exitf("dwarf: missing type (no data): %s", n)
	}

	return symIdx
}

func (d *dwctxt) dotypedef(parent *dwarf.DWDie, name string, def *dwarf.DWDie) *dwarf.DWDie {