Exemplo n.º 1
0
func machoreloc1(r *ld.Reloc, sectoff int64) int {
	var v uint32

	rs := r.Xsym

	// ld64 has a bug handling MACHO_ARM64_RELOC_UNSIGNED with !extern relocation.
	// see cmd/avail/ld/data.go for details. The workaround is that don't use !extern
	// UNSIGNED relocation at all.
	if rs.Type == obj.SHOSTOBJ || r.Type == obj.R_CALLARM64 || r.Type == obj.R_ADDRARM64 || r.Type == obj.R_ADDR {
		if rs.Dynid < 0 {
			ld.Diag("reloc %d to non-macho symbol %s type=%d", r.Type, rs.Name, rs.Type)
			return -1
		}

		v = uint32(rs.Dynid)
		v |= 1 << 27 // external relocation
	} else {
		v = uint32(rs.Sect.Extnum)
		if v == 0 {
			ld.Diag("reloc %d to symbol %s in non-macho section %s type=%d", r.Type, rs.Name, rs.Sect.Name, rs.Type)
			return -1
		}
	}

	switch r.Type {
	default:
		return -1

	case obj.R_ADDR:
		v |= ld.MACHO_ARM64_RELOC_UNSIGNED << 28

	case obj.R_CALLARM64:
		if r.Xadd != 0 {
			ld.Diag("ld64 doesn't allow BR26 reloc with non-zero addend: %s+%d", rs.Name, r.Xadd)
		}

		v |= 1 << 24 // pc-relative bit
		v |= ld.MACHO_ARM64_RELOC_BRANCH26 << 28

	case obj.R_ADDRARM64:
		r.Siz = 4
		// Two relocation entries: MACHO_ARM64_RELOC_PAGEOFF12 MACHO_ARM64_RELOC_PAGE21
		// if r.Xadd is non-zero, add two MACHO_ARM64_RELOC_ADDEND.
		if r.Xadd != 0 {
			ld.Thearch.Lput(uint32(sectoff + 4))
			ld.Thearch.Lput((ld.MACHO_ARM64_RELOC_ADDEND << 28) | (2 << 25) | uint32(r.Xadd&0xffffff))
		}
		ld.Thearch.Lput(uint32(sectoff + 4))
		ld.Thearch.Lput(v | (ld.MACHO_ARM64_RELOC_PAGEOFF12 << 28) | (2 << 25))
		if r.Xadd != 0 {
			ld.Thearch.Lput(uint32(sectoff))
			ld.Thearch.Lput((ld.MACHO_ARM64_RELOC_ADDEND << 28) | (2 << 25) | uint32(r.Xadd&0xffffff))
		}
		v |= 1 << 24 // pc-relative bit
		v |= ld.MACHO_ARM64_RELOC_PAGE21 << 28
	}

	switch r.Siz {
	default:
		return -1

	case 1:
		v |= 0 << 25

	case 2:
		v |= 1 << 25

	case 4:
		v |= 2 << 25

	case 8:
		v |= 3 << 25
	}

	ld.Thearch.Lput(uint32(sectoff))
	ld.Thearch.Lput(v)
	return 0
}