strdata := make(map[int]string, nnames)
	strlens := make(map[int]int, nnames)

	buildStrings := func() {
		for n, strlen := range strlens {
			data := strdata[n]
			if len(data) <= strlen {
				fatalf("invalid string literal")
			}
			strs[n] = data[:strlen]
		}
	}

	if f, err := macho.Open(gccTmp()); err == nil {
		defer f.Close()
		d, err := f.DWARF()
		if err != nil {