Modtaboff      uint32
		Nmodtab        uint32
		Extrefsymoff   uint32
		Nextrefsyms    uint32
		Indirectsymoff uint32
		Nindirectsyms  uint32
		Extreloff      uint32
		Nextrel        uint32
		Locreloff      uint32
		Nlocrel        uint32
	}

	// A DylibCmd is a Mach-O load dynamic library command.
	DylibCmd struct {
		Cmd            LoadCmd
		Len            uint32
		Name           uint32

	modtaboff      uint32
	nmodtab        uint32
	extrefsymoff   uint32
	nextrefsyms    uint32
	indirectsymoff uint32
	nindirectsyms  uint32
	extreloff      uint32
	nextrel        uint32
	locreloff      uint32
	nlocrel        uint32
	indir          []uint32
}

// ldMachoSym.type_
const (
	N_EXT  = 0x01
	N_TYPE = 0x1e
	N_STAB = 0xe0
)

// ldMachoSym.desc
const (

		case macho.LoadCmdDysymtab:
			err = machoUpdateLoadCommand(reader, linkseg, linkoffset, &macho.DysymtabCmd{}, "Tocoffset", "Modtaboff", "Extrefsymoff", "Indirectsymoff", "Extreloff", "Locreloff")
		case LC_CODE_SIGNATURE, LC_SEGMENT_SPLIT_INFO, LC_FUNCTION_STARTS, LC_DATA_IN_CODE, LC_DYLIB_CODE_SIGN_DRS,
			LC_DYLD_EXPORTS_TRIE, LC_DYLD_CHAINED_FIXUPS:

	ml.data[12] = uint32(base + s1)     /* indirectsymoff */
	ml.data[13] = uint32((s2 + s3) / 4) /* nindirectsyms */

	ml.data[14] = 0 /* extreloff */
	ml.data[15] = 0 /* nextrel */
	ml.data[16] = 0 /* locreloff */
	ml.data[17] = 0 /* nlocrel */
}

func doMachoLink(ctxt *Link) int64 {
	machosymtab(ctxt)
	machoDyldInfo(ctxt)

	ldr := ctxt.loader

	// write data that will be linkedit section

			narg++

		case xArgRel8:
			inst.PCRelOff = immcpos
			inst.PCRel = 1
			inst.Args[narg] = Rel(int8(immc))
			narg++

		case xArgRel16:
			inst.PCRelOff = immcpos
			inst.PCRel = 2
			inst.Args[narg] = Rel(int16(immc))
			narg++

		case xArgRel32:
			inst.PCRelOff = immcpos
			inst.PCRel = 4
			inst.Args[narg] = Rel(int32(immc))
			narg++

	MemBytes int      // size of memory argument in bytes: 1, 2, 4, 8, 16, and so on.
	Len      int      // length of encoded instruction in bytes
	PCRel    int      // length of PC-relative address in instruction encoding
	PCRelOff int      // index of start of PC-relative address in instruction encoding
}

// Prefixes is an array of prefixes associated with a single instruction.
// The prefixes are listed in the same order as found in the instruction:

		{"DysymtabCmd.Iextdefsym", Field, 0},
		{"DysymtabCmd.Ilocalsym", Field, 0},
		{"DysymtabCmd.Indirectsymoff", Field, 0},
		{"DysymtabCmd.Iundefsym", Field, 0},
		{"DysymtabCmd.Len", Field, 0},
		{"DysymtabCmd.Locreloff", Field, 0},
		{"DysymtabCmd.Modtaboff", Field, 0},
		{"DysymtabCmd.Nextdefsym", Field, 0},
		{"DysymtabCmd.Nextrefsyms", Field, 0},
		{"DysymtabCmd.Nextrel", Field, 0},
		{"DysymtabCmd.Nindirectsyms", Field, 0},

pkg debug/macho, type DysymtabCmd struct, Indirectsymoff uint32
pkg debug/macho, type DysymtabCmd struct, Iundefsym uint32
pkg debug/macho, type DysymtabCmd struct, Len uint32
pkg debug/macho, type DysymtabCmd struct, Locreloff uint32
pkg debug/macho, type DysymtabCmd struct, Modtaboff uint32
pkg debug/macho, type DysymtabCmd struct, Nextdefsym uint32
pkg debug/macho, type DysymtabCmd struct, Nextrefsyms uint32