예제 #1
0
파일: asm.go 프로젝트: achanda/go
// Convert the direct jump relocation r to refer to a trampoline if the target is too far
func trampoline(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol) {
	switch r.Type {
	case obj.R_CALLARM:
		// r.Add is the instruction
		// low 24-bit encodes the target address
		t := (ld.Symaddr(r.Sym) + int64(signext24(r.Add&0xffffff)*4) - (s.Value + int64(r.Off))) / 4
		if t > 0x7fffff || t < -0x800000 || (*ld.FlagDebugTramp > 1 && s.File != r.Sym.File) {
			// direct call too far, need to insert trampoline.
			// look up existing trampolines first. if we found one within the range
			// of direct call, we can reuse it. otherwise create a new one.
			offset := (signext24(r.Add&0xffffff) + 2) * 4
			var tramp *ld.Symbol
			for i := 0; ; i++ {
				name := r.Sym.Name + fmt.Sprintf("%+d-tramp%d", offset, i)
				tramp = ctxt.Syms.Lookup(name, int(r.Sym.Version))
				if tramp.Type == obj.SDYNIMPORT {
					// don't reuse trampoline defined in other module
					continue
				}
				if tramp.Value == 0 {
					// either the trampoline does not exist -- we need to create one,
					// or found one the address which is not assigned -- this will be
					// laid down immediately after the current function. use this one.
					break
				}

				t = (ld.Symaddr(tramp) - 8 - (s.Value + int64(r.Off))) / 4
				if t >= -0x800000 && t < 0x7fffff {
					// found an existing trampoline that is not too far
					// we can just use it
					break
				}
			}
			if tramp.Type == 0 {
				// trampoline does not exist, create one
				ctxt.AddTramp(tramp)
				if ctxt.DynlinkingGo() {
					if immrot(uint32(offset)) == 0 {
						ld.Errorf(s, "odd offset in dynlink direct call: %v+%d", r.Sym, offset)
					}
					gentrampdyn(tramp, r.Sym, int64(offset))
				} else if ld.Buildmode == ld.BuildmodeCArchive || ld.Buildmode == ld.BuildmodeCShared || ld.Buildmode == ld.BuildmodePIE {
					gentramppic(tramp, r.Sym, int64(offset))
				} else {
					gentramp(tramp, r.Sym, int64(offset))
				}
			}
			// modify reloc to point to tramp, which will be resolved later
			r.Sym = tramp
			r.Add = r.Add&0xff000000 | 0xfffffe // clear the offset embedded in the instruction
			r.Done = 0
		}
	default:
		ld.Errorf(s, "trampoline called with non-jump reloc: %v", r.Type)
	}
}
예제 #2
0
파일: asm.go 프로젝트: achanda/go
func machoreloc1(s *ld.Symbol, r *ld.Reloc, sectoff int64) int {
	var v uint32

	rs := r.Xsym

	if rs.Type == obj.SHOSTOBJ {
		if rs.Dynid < 0 {
			ld.Errorf(s, "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.Errorf(s, "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_GENERIC_RELOC_VANILLA << 28

	case obj.R_CALL,
		obj.R_PCREL:
		v |= 1 << 24 // pc-relative bit
		v |= ld.MACHO_GENERIC_RELOC_VANILLA << 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
}
예제 #3
0
파일: asm.go 프로젝트: kuangchanglang/go
func archrelocaddr(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol, val *int64) int {
	var o1, o2 uint32
	if ctxt.Arch.ByteOrder == binary.BigEndian {
		o1 = uint32(*val >> 32)
		o2 = uint32(*val)
	} else {
		o1 = uint32(*val)
		o2 = uint32(*val >> 32)
	}

	// We are spreading a 31-bit address across two instructions, putting the
	// high (adjusted) part in the low 16 bits of the first instruction and the
	// low part in the low 16 bits of the second instruction, or, in the DS case,
	// bits 15-2 (inclusive) of the address into bits 15-2 of the second
	// instruction (it is an error in this case if the low 2 bits of the address
	// are non-zero).

	t := ld.Symaddr(r.Sym) + r.Add
	if t < 0 || t >= 1<<31 {
		ld.Errorf(s, "relocation for %s is too big (>=2G): %d", s.Name, ld.Symaddr(r.Sym))
	}
	if t&0x8000 != 0 {
		t += 0x10000
	}

	switch r.Type {
	case obj.R_ADDRPOWER:
		o1 |= (uint32(t) >> 16) & 0xffff
		o2 |= uint32(t) & 0xffff

	case obj.R_ADDRPOWER_DS:
		o1 |= (uint32(t) >> 16) & 0xffff
		if t&3 != 0 {
			ld.Errorf(s, "bad DS reloc for %s: %d", s.Name, ld.Symaddr(r.Sym))
		}
		o2 |= uint32(t) & 0xfffc

	default:
		return -1
	}

	if ctxt.Arch.ByteOrder == binary.BigEndian {
		*val = int64(o1)<<32 | int64(o2)
	} else {
		*val = int64(o2)<<32 | int64(o1)
	}
	return 0
}
예제 #4
0
파일: asm.go 프로젝트: achanda/go
func pereloc1(s *ld.Symbol, r *ld.Reloc, sectoff int64) bool {
	var v uint32

	rs := r.Xsym

	if rs.Dynid < 0 {
		ld.Errorf(s, "reloc %d to non-coff symbol %s type=%d", r.Type, rs.Name, rs.Type)
		return false
	}

	ld.Thearch.Lput(uint32(sectoff))
	ld.Thearch.Lput(uint32(rs.Dynid))

	switch r.Type {
	default:
		return false

	case obj.R_ADDR:
		if r.Siz == 8 {
			v = ld.IMAGE_REL_AMD64_ADDR64
		} else {
			v = ld.IMAGE_REL_AMD64_ADDR32
		}

	case obj.R_CALL,
		obj.R_PCREL:
		v = ld.IMAGE_REL_AMD64_REL32
	}

	ld.Thearch.Wput(uint16(v))

	return true
}
예제 #5
0
파일: asm.go 프로젝트: achanda/go
func archrelocvariant(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol, t int64) int64 {
	switch r.Variant & ld.RV_TYPE_MASK {
	default:
		ld.Errorf(s, "unexpected relocation variant %d", r.Variant)
		return t

	case ld.RV_NONE:
		return t

	case ld.RV_390_DBL:
		if (t & 1) != 0 {
			ld.Errorf(s, "%s+%v is not 2-byte aligned", r.Sym.Name, r.Sym.Value)
		}
		return t >> 1
	}
}
예제 #6
0
파일: asm.go 프로젝트: achanda/go
func addpltsym(ctxt *ld.Link, s *ld.Symbol) {
	if s.Plt >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)

	if ld.Iself {
		plt := ctxt.Syms.Lookup(".plt", 0)
		got := ctxt.Syms.Lookup(".got.plt", 0)
		rel := ctxt.Syms.Lookup(".rel.plt", 0)
		if plt.Size == 0 {
			elfsetupplt(ctxt)
		}

		// jmpq *got+size
		ld.Adduint8(ctxt, plt, 0xff)

		ld.Adduint8(ctxt, plt, 0x25)
		ld.Addaddrplus(ctxt, plt, got, got.Size)

		// add to got: pointer to current pos in plt
		ld.Addaddrplus(ctxt, got, plt, plt.Size)

		// pushl $x
		ld.Adduint8(ctxt, plt, 0x68)

		ld.Adduint32(ctxt, plt, uint32(rel.Size))

		// jmp .plt
		ld.Adduint8(ctxt, plt, 0xe9)

		ld.Adduint32(ctxt, plt, uint32(-(plt.Size + 4)))

		// rel
		ld.Addaddrplus(ctxt, rel, got, got.Size-4)

		ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_386_JMP_SLOT))

		s.Plt = int32(plt.Size - 16)
	} else if ld.Headtype == obj.Hdarwin {
		// Same laziness as in 6l.

		plt := ctxt.Syms.Lookup(".plt", 0)

		addgotsym(ctxt, s)

		ld.Adduint32(ctxt, ctxt.Syms.Lookup(".linkedit.plt", 0), uint32(s.Dynid))

		// jmpq *got+size(IP)
		s.Plt = int32(plt.Size)

		ld.Adduint8(ctxt, plt, 0xff)
		ld.Adduint8(ctxt, plt, 0x25)
		ld.Addaddrplus(ctxt, plt, ctxt.Syms.Lookup(".got", 0), int64(s.Got))
	} else {
		ld.Errorf(s, "addpltsym: unsupported binary format")
	}
}
예제 #7
0
파일: asm.go 프로젝트: kuangchanglang/go
// Convert the direct jump relocation r to refer to a trampoline if the target is too far
func trampoline(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol) {
	switch r.Type {
	case obj.R_CALLARM:
		// r.Add is the instruction
		// low 24-bit encodes the target address
		t := (ld.Symaddr(r.Sym) + int64(signext24(r.Add&0xffffff)*4) - (s.Value + int64(r.Off))) / 4
		if t > 0x7fffff || t < -0x800000 || (*ld.FlagDebugTramp > 1 && s.File != r.Sym.File) {
			// direct call too far, need to insert trampoline
			offset := (signext24(r.Add&0xffffff) + 2) * 4
			var tramp *ld.Symbol
			for i := 0; ; i++ {
				name := r.Sym.Name + fmt.Sprintf("%+d-tramp%d", offset, i)
				tramp = ctxt.Syms.Lookup(name, int(r.Sym.Version))
				if tramp.Value == 0 {
					// either the trampoline does not exist -- we need to create one,
					// or found one the address which is not assigned -- this will be
					// laid down immediately after the current function. use this one.
					break
				}

				t = (ld.Symaddr(tramp) - 8 - (s.Value + int64(r.Off))) / 4
				if t >= -0x800000 && t < 0x7fffff {
					// found an existing trampoline that is not too far
					// we can just use it
					break
				}
			}
			if tramp.Type == 0 {
				// trampoline does not exist, create one
				ctxt.AddTramp(tramp)
				tramp.Size = 12 // 3 instructions
				tramp.P = make([]byte, tramp.Size)
				t = ld.Symaddr(r.Sym) + int64(offset)
				o1 := uint32(0xe5900000 | 11<<12 | 15<<16) // MOVW (R15), R11 // R15 is actual pc + 8
				o2 := uint32(0xe12fff10 | 11)              // JMP  (R11)
				o3 := uint32(t)                            // WORD $target
				ld.SysArch.ByteOrder.PutUint32(tramp.P, o1)
				ld.SysArch.ByteOrder.PutUint32(tramp.P[4:], o2)
				ld.SysArch.ByteOrder.PutUint32(tramp.P[8:], o3)
			}
			// modify reloc to point to tramp, which will be resolved later
			r.Sym = tramp
			r.Add = r.Add&0xff000000 | 0xfffffe // clear the offset embedded in the instruction
			r.Done = 0
		}
	default:
		ld.Errorf(s, "trampoline called with non-jump reloc: %v", r.Type)
	}
}
예제 #8
0
파일: asm.go 프로젝트: kuangchanglang/go
func addgotsyminternal(ctxt *ld.Link, s *ld.Symbol) {
	if s.Got >= 0 {
		return
	}

	got := ctxt.Syms.Lookup(".got", 0)
	s.Got = int32(got.Size)

	ld.Addaddrplus(ctxt, got, s, 0)

	if ld.Iself {
	} else {
		ld.Errorf(s, "addgotsyminternal: unsupported binary format")
	}
}
예제 #9
0
파일: asm.go 프로젝트: kuangchanglang/go
// Return the value of .TOC. for symbol s
func symtoc(ctxt *ld.Link, s *ld.Symbol) int64 {
	var toc *ld.Symbol

	if s.Outer != nil {
		toc = ctxt.Syms.ROLookup(".TOC.", int(s.Outer.Version))
	} else {
		toc = ctxt.Syms.ROLookup(".TOC.", int(s.Version))
	}

	if toc == nil {
		ld.Errorf(s, "TOC-relative relocation in object without .TOC.")
		return 0
	}

	return toc.Value
}
예제 #10
0
파일: asm.go 프로젝트: kuangchanglang/go
func addgotsym(ctxt *ld.Link, s *ld.Symbol) {
	if s.Got >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)
	got := ctxt.Syms.Lookup(".got", 0)
	s.Got = int32(got.Size)
	ld.Adduint32(ctxt, got, 0)

	if ld.Iself {
		rel := ctxt.Syms.Lookup(".rel", 0)
		ld.Addaddrplus(ctxt, rel, got, int64(s.Got))
		ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_ARM_GLOB_DAT))
	} else {
		ld.Errorf(s, "addgotsym: unsupported binary format")
	}
}
예제 #11
0
파일: asm.go 프로젝트: kuangchanglang/go
func addpltsym(ctxt *ld.Link, s *ld.Symbol) {
	if s.Plt >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)

	if ld.Iself {
		plt := ctxt.Syms.Lookup(".plt", 0)
		rela := ctxt.Syms.Lookup(".rela.plt", 0)
		if plt.Size == 0 {
			elfsetupplt(ctxt)
		}

		// Create the glink resolver if necessary
		glink := ensureglinkresolver(ctxt)

		// Write symbol resolver stub (just a branch to the
		// glink resolver stub)
		r := ld.Addrel(glink)

		r.Sym = glink
		r.Off = int32(glink.Size)
		r.Siz = 4
		r.Type = obj.R_CALLPOWER
		ld.Adduint32(ctxt, glink, 0x48000000) // b .glink

		// In the ppc64 ABI, the dynamic linker is responsible
		// for writing the entire PLT.  We just need to
		// reserve 8 bytes for each PLT entry and generate a
		// JMP_SLOT dynamic relocation for it.
		//
		// TODO(austin): ABI v1 is different
		s.Plt = int32(plt.Size)

		plt.Size += 8

		ld.Addaddrplus(ctxt, rela, plt, int64(s.Plt))
		ld.Adduint64(ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_PPC64_JMP_SLOT))
		ld.Adduint64(ctxt, rela, 0)
	} else {
		ld.Errorf(s, "addpltsym: unsupported binary format")
	}
}
예제 #12
0
파일: asm.go 프로젝트: achanda/go
func addgotsym(ctxt *ld.Link, s *ld.Symbol) {
	if s.Got >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)
	got := ctxt.Syms.Lookup(".got", 0)
	s.Got = int32(got.Size)
	ld.Adduint64(ctxt, got, 0)

	if ld.Iself {
		rela := ctxt.Syms.Lookup(".rela", 0)
		ld.Addaddrplus(ctxt, rela, got, int64(s.Got))
		ld.Adduint64(ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_X86_64_GLOB_DAT))
		ld.Adduint64(ctxt, rela, 0)
	} else if ld.Headtype == obj.Hdarwin {
		ld.Adduint32(ctxt, ctxt.Syms.Lookup(".linkedit.got", 0), uint32(s.Dynid))
	} else {
		ld.Errorf(s, "addgotsym: unsupported binary format")
	}
}
예제 #13
0
파일: asm.go 프로젝트: kuangchanglang/go
func addpltsym(ctxt *ld.Link, s *ld.Symbol) {
	if s.Plt >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)

	if ld.Iself {
		plt := ctxt.Syms.Lookup(".plt", 0)
		got := ctxt.Syms.Lookup(".got.plt", 0)
		rel := ctxt.Syms.Lookup(".rel.plt", 0)
		if plt.Size == 0 {
			elfsetupplt(ctxt)
		}

		// .got entry
		s.Got = int32(got.Size)

		// In theory, all GOT should point to the first PLT entry,
		// Linux/ARM's dynamic linker will do that for us, but FreeBSD/ARM's
		// dynamic linker won't, so we'd better do it ourselves.
		ld.Addaddrplus(ctxt, got, plt, 0)

		// .plt entry, this depends on the .got entry
		s.Plt = int32(plt.Size)

		addpltreloc(ctxt, plt, got, s, obj.R_PLT0) // add lr, pc, #0xXX00000
		addpltreloc(ctxt, plt, got, s, obj.R_PLT1) // add lr, lr, #0xYY000
		addpltreloc(ctxt, plt, got, s, obj.R_PLT2) // ldr pc, [lr, #0xZZZ]!

		// rel
		ld.Addaddrplus(ctxt, rel, got, int64(s.Got))

		ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_ARM_JUMP_SLOT))
	} else {
		ld.Errorf(s, "addpltsym: unsupported binary format")
	}
}
예제 #14
0
파일: asm.go 프로젝트: achanda/go
func archreloc(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		switch r.Type {
		default:
			return -1

		case obj.R_ADDRMIPS,
			obj.R_ADDRMIPSU:
			r.Done = 0

			// set up addend for eventual relocation via outer symbol.
			rs := r.Sym
			r.Xadd = r.Add
			for rs.Outer != nil {
				r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
				rs = rs.Outer
			}

			if rs.Type != obj.SHOSTOBJ && rs.Type != obj.SDYNIMPORT && rs.Sect == nil {
				ld.Errorf(s, "missing section for %s", rs.Name)
			}
			r.Xsym = rs

			return 0

		case obj.R_ADDRMIPSTLS,
			obj.R_CALLMIPS,
			obj.R_JMPMIPS:
			r.Done = 0
			r.Xsym = r.Sym
			r.Xadd = r.Add
			return 0
		}
	}

	switch r.Type {
	case obj.R_CONST:
		*val = r.Add
		return 0

	case obj.R_GOTOFF:
		*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ctxt.Syms.Lookup(".got", 0))
		return 0

	case obj.R_ADDRMIPS,
		obj.R_ADDRMIPSU:
		t := ld.Symaddr(r.Sym) + r.Add
		o1 := ld.SysArch.ByteOrder.Uint32(s.P[r.Off:])
		if r.Type == obj.R_ADDRMIPS {
			*val = int64(o1&0xffff0000 | uint32(t)&0xffff)
		} else {
			*val = int64(o1&0xffff0000 | uint32((t+1<<15)>>16)&0xffff)
		}
		return 0

	case obj.R_ADDRMIPSTLS:
		// thread pointer is at 0x7000 offset from the start of TLS data area
		t := ld.Symaddr(r.Sym) + r.Add - 0x7000
		if t < -32768 || t >= 32678 {
			ld.Errorf(s, "TLS offset out of range %d", t)
		}
		o1 := ld.SysArch.ByteOrder.Uint32(s.P[r.Off:])
		*val = int64(o1&0xffff0000 | uint32(t)&0xffff)
		return 0

	case obj.R_CALLMIPS,
		obj.R_JMPMIPS:
		// Low 26 bits = (S + A) >> 2
		t := ld.Symaddr(r.Sym) + r.Add
		o1 := ld.SysArch.ByteOrder.Uint32(s.P[r.Off:])
		*val = int64(o1&0xfc000000 | uint32(t>>2)&^0xfc000000)
		return 0
	}

	return -1
}
예제 #15
0
파일: asm.go 프로젝트: Harvey-OS/go
func asmb(ctxt *ld.Link) {
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f asmb\n", obj.Cputime())
	}

	if ld.Iself {
		ld.Asmbelfsetup()
	}

	sect := ld.Segtext.Sect
	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
	ld.Codeblk(ctxt, int64(sect.Vaddr), int64(sect.Length))
	for sect = sect.Next; sect != nil; sect = sect.Next {
		ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
		ld.Datblk(ctxt, int64(sect.Vaddr), int64(sect.Length))
	}

	if ld.Segrodata.Filelen > 0 {
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f rodatblk\n", obj.Cputime())
		}

		ld.Cseek(int64(ld.Segrodata.Fileoff))
		ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f datblk\n", obj.Cputime())
	}

	ld.Cseek(int64(ld.Segdata.Fileoff))
	ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))

	ld.Cseek(int64(ld.Segdwarf.Fileoff))
	ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen))

	/* output symbol table */
	ld.Symsize = 0

	ld.Lcsize = 0
	symo := uint32(0)
	if !*ld.FlagS {
		if !ld.Iself {
			ld.Errorf(nil, "unsupported executable format")
		}
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f sym\n", obj.Cputime())
		}
		symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
		symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound)))

		ld.Cseek(int64(symo))
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f elfsym\n", obj.Cputime())
		}
		ld.Asmelfsym(ctxt)
		ld.Cflush()
		ld.Cwrite(ld.Elfstrdat)

		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f dwarf\n", obj.Cputime())
		}

		if ld.Linkmode == ld.LinkExternal {
			ld.Elfemitreloc(ctxt)
		}
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f header\n", obj.Cputime())
	}

	ld.Cseek(0)
	switch ld.Headtype {
	default:
		ld.Errorf(nil, "unsupported operating system")
	case obj.Hlinux:
		ld.Asmbelf(ctxt, int64(symo))
	}

	ld.Cflush()
	if *ld.FlagC {
		fmt.Printf("textsize=%d\n", ld.Segtext.Filelen)
		fmt.Printf("datsize=%d\n", ld.Segdata.Filelen)
		fmt.Printf("bsssize=%d\n", ld.Segdata.Length-ld.Segdata.Filelen)
		fmt.Printf("symsize=%d\n", ld.Symsize)
		fmt.Printf("lcsize=%d\n", ld.Lcsize)
		fmt.Printf("total=%d\n", ld.Segtext.Filelen+ld.Segdata.Length+uint64(ld.Symsize)+uint64(ld.Lcsize))
	}
}
예제 #16
0
파일: asm.go 프로젝트: kuangchanglang/go
func archrelocvariant(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol, t int64) int64 {
	switch r.Variant & ld.RV_TYPE_MASK {
	default:
		ld.Errorf(s, "unexpected relocation variant %d", r.Variant)
		fallthrough

	case ld.RV_NONE:
		return t

	case ld.RV_POWER_LO:
		if r.Variant&ld.RV_CHECK_OVERFLOW != 0 {
			// Whether to check for signed or unsigned
			// overflow depends on the instruction
			var o1 uint32
			if ctxt.Arch.ByteOrder == binary.BigEndian {
				o1 = ld.Be32(s.P[r.Off-2:])
			} else {
				o1 = ld.Le32(s.P[r.Off:])
			}
			switch o1 >> 26 {
			case 24, // ori
				26, // xori
				28: // andi
				if t>>16 != 0 {
					goto overflow
				}

			default:
				if int64(int16(t)) != t {
					goto overflow
				}
			}
		}

		return int64(int16(t))

	case ld.RV_POWER_HA:
		t += 0x8000
		fallthrough

		// Fallthrough
	case ld.RV_POWER_HI:
		t >>= 16

		if r.Variant&ld.RV_CHECK_OVERFLOW != 0 {
			// Whether to check for signed or unsigned
			// overflow depends on the instruction
			var o1 uint32
			if ctxt.Arch.ByteOrder == binary.BigEndian {
				o1 = ld.Be32(s.P[r.Off-2:])
			} else {
				o1 = ld.Le32(s.P[r.Off:])
			}
			switch o1 >> 26 {
			case 25, // oris
				27, // xoris
				29: // andis
				if t>>16 != 0 {
					goto overflow
				}

			default:
				if int64(int16(t)) != t {
					goto overflow
				}
			}
		}

		return int64(int16(t))

	case ld.RV_POWER_DS:
		var o1 uint32
		if ctxt.Arch.ByteOrder == binary.BigEndian {
			o1 = uint32(ld.Be16(s.P[r.Off:]))
		} else {
			o1 = uint32(ld.Le16(s.P[r.Off:]))
		}
		if t&3 != 0 {
			ld.Errorf(s, "relocation for %s+%d is not aligned: %d", r.Sym.Name, r.Off, t)
		}
		if (r.Variant&ld.RV_CHECK_OVERFLOW != 0) && int64(int16(t)) != t {
			goto overflow
		}
		return int64(o1)&0x3 | int64(int16(t))
	}

overflow:
	ld.Errorf(s, "relocation for %s+%d is too big: %d", r.Sym.Name, r.Off, t)
	return t
}
예제 #17
0
파일: asm.go 프로젝트: achanda/go
func adddynrel(ctxt *ld.Link, s *ld.Symbol, r *ld.Reloc) bool {
	targ := r.Sym

	switch r.Type {
	default:
		if r.Type >= 256 {
			ld.Errorf(s, "unexpected relocation type %d", r.Type)
			return false
		}

		// Handle relocations found in ELF object files.
	case 256 + ld.R_390_12,
		256 + ld.R_390_GOT12:
		ld.Errorf(s, "s390x 12-bit relocations have not been implemented (relocation type %d)", r.Type-256)
		return false

	case 256 + ld.R_390_8,
		256 + ld.R_390_16,
		256 + ld.R_390_32,
		256 + ld.R_390_64:
		if targ.Type == obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected R_390_nn relocation for dynamic symbol %s", targ.Name)
		}
		r.Type = obj.R_ADDR
		return true

	case 256 + ld.R_390_PC16,
		256 + ld.R_390_PC32,
		256 + ld.R_390_PC64:
		if targ.Type == obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected R_390_PCnn relocation for dynamic symbol %s", targ.Name)
		}
		if targ.Type == 0 || targ.Type == obj.SXREF {
			ld.Errorf(s, "unknown symbol %s in pcrel", targ.Name)
		}
		r.Type = obj.R_PCREL
		r.Add += int64(r.Siz)
		return true

	case 256 + ld.R_390_GOT16,
		256 + ld.R_390_GOT32,
		256 + ld.R_390_GOT64:
		ld.Errorf(s, "unimplemented S390x relocation: %v", r.Type-256)
		return true

	case 256 + ld.R_390_PLT16DBL,
		256 + ld.R_390_PLT32DBL:
		r.Type = obj.R_PCREL
		r.Variant = ld.RV_390_DBL
		r.Add += int64(r.Siz)
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ctxt, targ)
			r.Sym = ctxt.Syms.Lookup(".plt", 0)
			r.Add += int64(targ.Plt)
		}
		return true

	case 256 + ld.R_390_PLT32,
		256 + ld.R_390_PLT64:
		r.Type = obj.R_PCREL
		r.Add += int64(r.Siz)
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ctxt, targ)
			r.Sym = ctxt.Syms.Lookup(".plt", 0)
			r.Add += int64(targ.Plt)
		}
		return true

	case 256 + ld.R_390_COPY:
		ld.Errorf(s, "unimplemented S390x relocation: %v", r.Type-256)
		return false

	case 256 + ld.R_390_GLOB_DAT:
		ld.Errorf(s, "unimplemented S390x relocation: %v", r.Type-256)
		return false

	case 256 + ld.R_390_JMP_SLOT:
		ld.Errorf(s, "unimplemented S390x relocation: %v", r.Type-256)
		return false

	case 256 + ld.R_390_RELATIVE:
		ld.Errorf(s, "unimplemented S390x relocation: %v", r.Type-256)
		return false

	case 256 + ld.R_390_GOTOFF:
		if targ.Type == obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected R_390_GOTOFF relocation for dynamic symbol %s", targ.Name)
		}
		r.Type = obj.R_GOTOFF
		return true

	case 256 + ld.R_390_GOTPC:
		r.Type = obj.R_PCREL
		r.Sym = ctxt.Syms.Lookup(".got", 0)
		r.Add += int64(r.Siz)
		return true

	case 256 + ld.R_390_PC16DBL,
		256 + ld.R_390_PC32DBL:
		r.Type = obj.R_PCREL
		r.Variant = ld.RV_390_DBL
		r.Add += int64(r.Siz)
		if targ.Type == obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected R_390_PCnnDBL relocation for dynamic symbol %s", targ.Name)
		}
		return true

	case 256 + ld.R_390_GOTPCDBL:
		r.Type = obj.R_PCREL
		r.Variant = ld.RV_390_DBL
		r.Sym = ctxt.Syms.Lookup(".got", 0)
		r.Add += int64(r.Siz)
		return true

	case 256 + ld.R_390_GOTENT:
		addgotsym(ctxt, targ)

		r.Type = obj.R_PCREL
		r.Variant = ld.RV_390_DBL
		r.Sym = ctxt.Syms.Lookup(".got", 0)
		r.Add += int64(targ.Got)
		r.Add += int64(r.Siz)
		return true
	}
	// Handle references to ELF symbols from our own object files.
	if targ.Type != obj.SDYNIMPORT {
		return true
	}

	return false
}
예제 #18
0
파일: asm.go 프로젝트: achanda/go
func machoreloc1(s *ld.Symbol, r *ld.Reloc, sectoff int64) int {
	var v uint32

	rs := r.Xsym

	if rs.Type == obj.SHOSTOBJ || r.Type == obj.R_PCREL || r.Type == obj.R_GOTPCREL {
		if rs.Dynid < 0 {
			ld.Errorf(s, "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.Errorf(s, "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_X86_64_RELOC_UNSIGNED << 28

	case obj.R_CALL:
		v |= 1 << 24 // pc-relative bit
		v |= ld.MACHO_X86_64_RELOC_BRANCH << 28

		// NOTE: Only works with 'external' relocation. Forced above.
	case obj.R_PCREL:
		v |= 1 << 24 // pc-relative bit
		v |= ld.MACHO_X86_64_RELOC_SIGNED << 28
	case obj.R_GOTPCREL:
		v |= 1 << 24 // pc-relative bit
		v |= ld.MACHO_X86_64_RELOC_GOT_LOAD << 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
}
예제 #19
0
파일: asm.go 프로젝트: kuangchanglang/go
func archreloc(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		switch r.Type {
		default:
			return -1

		case obj.R_POWER_TLS, obj.R_POWER_TLS_LE, obj.R_POWER_TLS_IE:
			r.Done = 0
			// check Outer is nil, Type is TLSBSS?
			r.Xadd = r.Add
			r.Xsym = r.Sym
			return 0

		case obj.R_ADDRPOWER,
			obj.R_ADDRPOWER_DS,
			obj.R_ADDRPOWER_TOCREL,
			obj.R_ADDRPOWER_TOCREL_DS,
			obj.R_ADDRPOWER_GOT,
			obj.R_ADDRPOWER_PCREL:
			r.Done = 0

			// set up addend for eventual relocation via outer symbol.
			rs := r.Sym
			r.Xadd = r.Add
			for rs.Outer != nil {
				r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
				rs = rs.Outer
			}

			if rs.Type != obj.SHOSTOBJ && rs.Type != obj.SDYNIMPORT && rs.Sect == nil {
				ld.Errorf(s, "missing section for %s", rs.Name)
			}
			r.Xsym = rs

			return 0

		case obj.R_CALLPOWER:
			r.Done = 0
			r.Xsym = r.Sym
			r.Xadd = r.Add
			return 0
		}
	}

	switch r.Type {
	case obj.R_CONST:
		*val = r.Add
		return 0

	case obj.R_GOTOFF:
		*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ctxt.Syms.Lookup(".got", 0))
		return 0

	case obj.R_ADDRPOWER, obj.R_ADDRPOWER_DS:
		return archrelocaddr(ctxt, r, s, val)

	case obj.R_CALLPOWER:
		// Bits 6 through 29 = (S + A - P) >> 2

		t := ld.Symaddr(r.Sym) + r.Add - (s.Value + int64(r.Off))
		if t&3 != 0 {
			ld.Errorf(s, "relocation for %s+%d is not aligned: %d", r.Sym.Name, r.Off, t)
		}
		if int64(int32(t<<6)>>6) != t {
			// TODO(austin) This can happen if text > 32M.
			// Add a call trampoline to .text in that case.
			ld.Errorf(s, "relocation for %s+%d is too big: %d", r.Sym.Name, r.Off, t)
		}

		*val |= int64(uint32(t) &^ 0xfc000003)
		return 0

	case obj.R_POWER_TOC: // S + A - .TOC.
		*val = ld.Symaddr(r.Sym) + r.Add - symtoc(ctxt, s)

		return 0

	case obj.R_POWER_TLS_LE:
		// The thread pointer points 0x7000 bytes after the start of the the
		// thread local storage area as documented in section "3.7.2 TLS
		// Runtime Handling" of "Power Architecture 64-Bit ELF V2 ABI
		// Specification".
		v := r.Sym.Value - 0x7000
		if int64(int16(v)) != v {
			ld.Errorf(s, "TLS offset out of range %d", v)
		}
		*val = (*val &^ 0xffff) | (v & 0xffff)
		return 0
	}

	return -1
}
예제 #20
0
파일: asm.go 프로젝트: kuangchanglang/go
func adddynrel(ctxt *ld.Link, s *ld.Symbol, r *ld.Reloc) bool {
	targ := r.Sym

	switch r.Type {
	default:
		if r.Type >= 256 {
			ld.Errorf(s, "unexpected relocation type %d", r.Type)
			return false
		}

		// Handle relocations found in ELF object files.
	case 256 + ld.R_PPC64_REL24:
		r.Type = obj.R_CALLPOWER

		// This is a local call, so the caller isn't setting
		// up r12 and r2 is the same for the caller and
		// callee. Hence, we need to go to the local entry
		// point.  (If we don't do this, the callee will try
		// to use r12 to compute r2.)
		r.Add += int64(r.Sym.Localentry) * 4

		if targ.Type == obj.SDYNIMPORT {
			// Should have been handled in elfsetupplt
			ld.Errorf(s, "unexpected R_PPC64_REL24 for dyn import")
		}

		return true

	case 256 + ld.R_PPC_REL32:
		r.Type = obj.R_PCREL
		r.Add += 4

		if targ.Type == obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected R_PPC_REL32 for dyn import")
		}

		return true

	case 256 + ld.R_PPC64_ADDR64:
		r.Type = obj.R_ADDR
		if targ.Type == obj.SDYNIMPORT {
			// These happen in .toc sections
			ld.Adddynsym(ctxt, targ)

			rela := ctxt.Syms.Lookup(".rela", 0)
			ld.Addaddrplus(ctxt, rela, s, int64(r.Off))
			ld.Adduint64(ctxt, rela, ld.ELF64_R_INFO(uint32(targ.Dynid), ld.R_PPC64_ADDR64))
			ld.Adduint64(ctxt, rela, uint64(r.Add))
			r.Type = 256 // ignore during relocsym
		}

		return true

	case 256 + ld.R_PPC64_TOC16:
		r.Type = obj.R_POWER_TOC
		r.Variant = ld.RV_POWER_LO | ld.RV_CHECK_OVERFLOW
		return true

	case 256 + ld.R_PPC64_TOC16_LO:
		r.Type = obj.R_POWER_TOC
		r.Variant = ld.RV_POWER_LO
		return true

	case 256 + ld.R_PPC64_TOC16_HA:
		r.Type = obj.R_POWER_TOC
		r.Variant = ld.RV_POWER_HA | ld.RV_CHECK_OVERFLOW
		return true

	case 256 + ld.R_PPC64_TOC16_HI:
		r.Type = obj.R_POWER_TOC
		r.Variant = ld.RV_POWER_HI | ld.RV_CHECK_OVERFLOW
		return true

	case 256 + ld.R_PPC64_TOC16_DS:
		r.Type = obj.R_POWER_TOC
		r.Variant = ld.RV_POWER_DS | ld.RV_CHECK_OVERFLOW
		return true

	case 256 + ld.R_PPC64_TOC16_LO_DS:
		r.Type = obj.R_POWER_TOC
		r.Variant = ld.RV_POWER_DS
		return true

	case 256 + ld.R_PPC64_REL16_LO:
		r.Type = obj.R_PCREL
		r.Variant = ld.RV_POWER_LO
		r.Add += 2 // Compensate for relocation size of 2
		return true

	case 256 + ld.R_PPC64_REL16_HI:
		r.Type = obj.R_PCREL
		r.Variant = ld.RV_POWER_HI | ld.RV_CHECK_OVERFLOW
		r.Add += 2
		return true

	case 256 + ld.R_PPC64_REL16_HA:
		r.Type = obj.R_PCREL
		r.Variant = ld.RV_POWER_HA | ld.RV_CHECK_OVERFLOW
		r.Add += 2
		return true
	}

	// Handle references to ELF symbols from our own object files.
	if targ.Type != obj.SDYNIMPORT {
		return true
	}

	// TODO(austin): Translate our relocations to ELF

	return false
}
예제 #21
0
파일: asm.go 프로젝트: achanda/go
func addpltsym(ctxt *ld.Link, s *ld.Symbol) {
	if s.Plt >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)

	if ld.Iself {
		plt := ctxt.Syms.Lookup(".plt", 0)
		got := ctxt.Syms.Lookup(".got", 0)
		rela := ctxt.Syms.Lookup(".rela.plt", 0)
		if plt.Size == 0 {
			elfsetupplt(ctxt)
		}
		// larl    %r1,_GLOBAL_OFFSET_TABLE_+index

		ld.Adduint8(ctxt, plt, 0xc0)
		ld.Adduint8(ctxt, plt, 0x10)
		ld.Addpcrelplus(ctxt, plt, got, got.Size+6) // need variant?

		// add to got: pointer to current pos in plt
		ld.Addaddrplus(ctxt, got, plt, plt.Size+8) // weird but correct
		// lg      %r1,0(%r1)
		ld.Adduint8(ctxt, plt, 0xe3)
		ld.Adduint8(ctxt, plt, 0x10)
		ld.Adduint8(ctxt, plt, 0x10)
		ld.Adduint8(ctxt, plt, 0x00)
		ld.Adduint8(ctxt, plt, 0x00)
		ld.Adduint8(ctxt, plt, 0x04)
		// br      %r1
		ld.Adduint8(ctxt, plt, 0x07)
		ld.Adduint8(ctxt, plt, 0xf1)
		// basr    %r1,%r0
		ld.Adduint8(ctxt, plt, 0x0d)
		ld.Adduint8(ctxt, plt, 0x10)
		// lgf     %r1,12(%r1)
		ld.Adduint8(ctxt, plt, 0xe3)
		ld.Adduint8(ctxt, plt, 0x10)
		ld.Adduint8(ctxt, plt, 0x10)
		ld.Adduint8(ctxt, plt, 0x0c)
		ld.Adduint8(ctxt, plt, 0x00)
		ld.Adduint8(ctxt, plt, 0x14)
		// jg .plt
		ld.Adduint8(ctxt, plt, 0xc0)
		ld.Adduint8(ctxt, plt, 0xf4)

		ld.Adduint32(ctxt, plt, uint32(-((plt.Size - 2) >> 1))) // roll-your-own relocation
		//.plt index
		ld.Adduint32(ctxt, plt, uint32(rela.Size)) // rela size before current entry

		// rela
		ld.Addaddrplus(ctxt, rela, got, got.Size-8)

		ld.Adduint64(ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_390_JMP_SLOT))
		ld.Adduint64(ctxt, rela, 0)

		s.Plt = int32(plt.Size - 32)

	} else {
		ld.Errorf(s, "addpltsym: unsupported binary format")
	}
}
예제 #22
0
파일: asm.go 프로젝트: achanda/go
func adddynrel(ctxt *ld.Link, s *ld.Symbol, r *ld.Reloc) bool {
	targ := r.Sym

	switch r.Type {
	default:
		if r.Type >= 256 {
			ld.Errorf(s, "unexpected relocation type %d", r.Type)
			return false
		}

		// Handle relocations found in ELF object files.
	case 256 + ld.R_X86_64_PC32:
		if targ.Type == obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected R_X86_64_PC32 relocation for dynamic symbol %s", targ.Name)
		}
		if targ.Type == 0 || targ.Type == obj.SXREF {
			ld.Errorf(s, "unknown symbol %s in pcrel", targ.Name)
		}
		r.Type = obj.R_PCREL
		r.Add += 4
		return true

	case 256 + ld.R_X86_64_PLT32:
		r.Type = obj.R_PCREL
		r.Add += 4
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ctxt, targ)
			r.Sym = ctxt.Syms.Lookup(".plt", 0)
			r.Add += int64(targ.Plt)
		}

		return true

	case 256 + ld.R_X86_64_GOTPCREL, 256 + ld.R_X86_64_GOTPCRELX, 256 + ld.R_X86_64_REX_GOTPCRELX:
		if targ.Type != obj.SDYNIMPORT {
			// have symbol
			if r.Off >= 2 && s.P[r.Off-2] == 0x8b {
				// turn MOVQ of GOT entry into LEAQ of symbol itself
				s.P[r.Off-2] = 0x8d

				r.Type = obj.R_PCREL
				r.Add += 4
				return true
			}
		}

		// fall back to using GOT and hope for the best (CMOV*)
		// TODO: just needs relocation, no need to put in .dynsym
		addgotsym(ctxt, targ)

		r.Type = obj.R_PCREL
		r.Sym = ctxt.Syms.Lookup(".got", 0)
		r.Add += 4
		r.Add += int64(targ.Got)
		return true

	case 256 + ld.R_X86_64_64:
		if targ.Type == obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected R_X86_64_64 relocation for dynamic symbol %s", targ.Name)
		}
		r.Type = obj.R_ADDR
		return true

	// Handle relocations found in Mach-O object files.
	case 512 + ld.MACHO_X86_64_RELOC_UNSIGNED*2 + 0,
		512 + ld.MACHO_X86_64_RELOC_SIGNED*2 + 0,
		512 + ld.MACHO_X86_64_RELOC_BRANCH*2 + 0:
		// TODO: What is the difference between all these?
		r.Type = obj.R_ADDR

		if targ.Type == obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected reloc for dynamic symbol %s", targ.Name)
		}
		return true

	case 512 + ld.MACHO_X86_64_RELOC_BRANCH*2 + 1:
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ctxt, targ)
			r.Sym = ctxt.Syms.Lookup(".plt", 0)
			r.Add = int64(targ.Plt)
			r.Type = obj.R_PCREL
			return true
		}
		fallthrough

		// fall through
	case 512 + ld.MACHO_X86_64_RELOC_UNSIGNED*2 + 1,
		512 + ld.MACHO_X86_64_RELOC_SIGNED*2 + 1,
		512 + ld.MACHO_X86_64_RELOC_SIGNED_1*2 + 1,
		512 + ld.MACHO_X86_64_RELOC_SIGNED_2*2 + 1,
		512 + ld.MACHO_X86_64_RELOC_SIGNED_4*2 + 1:
		r.Type = obj.R_PCREL

		if targ.Type == obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected pc-relative reloc for dynamic symbol %s", targ.Name)
		}
		return true

	case 512 + ld.MACHO_X86_64_RELOC_GOT_LOAD*2 + 1:
		if targ.Type != obj.SDYNIMPORT {
			// have symbol
			// turn MOVQ of GOT entry into LEAQ of symbol itself
			if r.Off < 2 || s.P[r.Off-2] != 0x8b {
				ld.Errorf(s, "unexpected GOT_LOAD reloc for non-dynamic symbol %s", targ.Name)
				return false
			}

			s.P[r.Off-2] = 0x8d
			r.Type = obj.R_PCREL
			return true
		}
		fallthrough

		// fall through
	case 512 + ld.MACHO_X86_64_RELOC_GOT*2 + 1:
		if targ.Type != obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", targ.Name)
		}
		addgotsym(ctxt, targ)
		r.Type = obj.R_PCREL
		r.Sym = ctxt.Syms.Lookup(".got", 0)
		r.Add += int64(targ.Got)
		return true
	}

	switch r.Type {
	case obj.R_CALL,
		obj.R_PCREL:
		if targ.Type != obj.SDYNIMPORT {
			// nothing to do, the relocation will be laid out in reloc
			return true
		}
		if ld.Headtype == obj.Hwindows || ld.Headtype == obj.Hwindowsgui {
			// nothing to do, the relocation will be laid out in pereloc1
			return true
		} else {
			// for both ELF and Mach-O
			addpltsym(ctxt, targ)
			r.Sym = ctxt.Syms.Lookup(".plt", 0)
			r.Add = int64(targ.Plt)
			return true
		}

	case obj.R_ADDR:
		if s.Type == obj.STEXT && ld.Iself {
			if ld.Headtype == obj.Hsolaris {
				addpltsym(ctxt, targ)
				r.Sym = ctxt.Syms.Lookup(".plt", 0)
				r.Add += int64(targ.Plt)
				return true
			}
			// The code is asking for the address of an external
			// function. We provide it with the address of the
			// correspondent GOT symbol.
			addgotsym(ctxt, targ)

			r.Sym = ctxt.Syms.Lookup(".got", 0)
			r.Add += int64(targ.Got)
			return true
		}

		// Process dynamic relocations for the data sections.
		if ld.Buildmode == ld.BuildmodePIE && ld.Linkmode == ld.LinkInternal {
			// When internally linking, generate dynamic relocations
			// for all typical R_ADDR relocations. The exception
			// are those R_ADDR that are created as part of generating
			// the dynamic relocations and must be resolved statically.
			//
			// There are three phases relevant to understanding this:
			//
			//	dodata()  // we are here
			//	address() // symbol address assignment
			//	reloc()   // resolution of static R_ADDR relocs
			//
			// At this point symbol addresses have not been
			// assigned yet (as the final size of the .rela section
			// will affect the addresses), and so we cannot write
			// the Elf64_Rela.r_offset now. Instead we delay it
			// until after the 'address' phase of the linker is
			// complete. We do this via Addaddrplus, which creates
			// a new R_ADDR relocation which will be resolved in
			// the 'reloc' phase.
			//
			// These synthetic static R_ADDR relocs must be skipped
			// now, or else we will be caught in an infinite loop
			// of generating synthetic relocs for our synthetic
			// relocs.
			switch s.Name {
			case ".dynsym", ".rela", ".got.plt", ".dynamic":
				return false
			}
		} else {
			// Either internally linking a static executable,
			// in which case we can resolve these relocations
			// statically in the 'reloc' phase, or externally
			// linking, in which case the relocation will be
			// prepared in the 'reloc' phase and passed to the
			// external linker in the 'asmb' phase.
			if s.Type != obj.SDATA && s.Type != obj.SRODATA {
				break
			}
		}

		if ld.Iself {
			// TODO: We generate a R_X86_64_64 relocation for every R_ADDR, even
			// though it would be more efficient (for the dynamic linker) if we
			// generated R_X86_RELATIVE instead.
			ld.Adddynsym(ctxt, targ)
			rela := ctxt.Syms.Lookup(".rela", 0)
			ld.Addaddrplus(ctxt, rela, s, int64(r.Off))
			if r.Siz == 8 {
				ld.Adduint64(ctxt, rela, ld.ELF64_R_INFO(uint32(targ.Dynid), ld.R_X86_64_64))
			} else {
				// TODO: never happens, remove.
				ld.Adduint64(ctxt, rela, ld.ELF64_R_INFO(uint32(targ.Dynid), ld.R_X86_64_32))
			}
			ld.Adduint64(ctxt, rela, uint64(r.Add))
			r.Type = 256 // ignore during relocsym
			return true
		}

		if ld.Headtype == obj.Hdarwin && s.Size == int64(ld.SysArch.PtrSize) && r.Off == 0 {
			// Mach-O relocations are a royal pain to lay out.
			// They use a compact stateful bytecode representation
			// that is too much bother to deal with.
			// Instead, interpret the C declaration
			//	void *_Cvar_stderr = &stderr;
			// as making _Cvar_stderr the name of a GOT entry
			// for stderr. This is separate from the usual GOT entry,
			// just in case the C code assigns to the variable,
			// and of course it only works for single pointers,
			// but we only need to support cgo and that's all it needs.
			ld.Adddynsym(ctxt, targ)

			got := ctxt.Syms.Lookup(".got", 0)
			s.Type = got.Type | obj.SSUB
			s.Outer = got
			s.Sub = got.Sub
			got.Sub = s
			s.Value = got.Size
			ld.Adduint64(ctxt, got, 0)
			ld.Adduint32(ctxt, ctxt.Syms.Lookup(".linkedit.got", 0), uint32(targ.Dynid))
			r.Type = 256 // ignore during relocsym
			return true
		}

		if ld.Headtype == obj.Hwindows || ld.Headtype == obj.Hwindowsgui {
			// nothing to do, the relocation will be laid out in pereloc1
			return true
		}
	}

	return false
}
예제 #23
0
파일: asm.go 프로젝트: achanda/go
// resolve direct jump relocation r in s, and add trampoline if necessary
func trampoline(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol) {

	t := ld.Symaddr(r.Sym) + r.Add - (s.Value + int64(r.Off))
	switch r.Type {
	case obj.R_CALLPOWER:

		// If branch offset is too far then create a trampoline.

		if int64(int32(t<<6)>>6) != t || (*ld.FlagDebugTramp > 1 && s.File != r.Sym.File) {
			var tramp *ld.Symbol
			for i := 0; ; i++ {

				// Using r.Add as part of the name is significant in functions like duffzero where the call
				// target is at some offset within the function.  Calls to duff+8 and duff+256 must appear as
				// distinct trampolines.

				name := r.Sym.Name
				if r.Add == 0 {
					name = name + fmt.Sprintf("-tramp%d", i)
				} else {
					name = name + fmt.Sprintf("%+x-tramp%d", r.Add, i)
				}

				// Look up the trampoline in case it already exists

				tramp = ctxt.Syms.Lookup(name, int(r.Sym.Version))
				if tramp.Value == 0 {
					break
				}

				t = ld.Symaddr(tramp) + r.Add - (s.Value + int64(r.Off))

				// If the offset of the trampoline that has been found is within range, use it.
				if int64(int32(t<<6)>>6) == t {
					break
				}
			}
			if tramp.Type == 0 {
				ctxt.AddTramp(tramp)
				tramp.Size = 16 // 4 instructions
				tramp.P = make([]byte, tramp.Size)
				t = ld.Symaddr(r.Sym) + r.Add
				f := t & 0xffff0000
				o1 := uint32(0x3fe00000 | (f >> 16)) // lis r31,trampaddr hi (r31 is temp reg)
				f = t & 0xffff
				o2 := uint32(0x63ff0000 | f) // ori r31,trampaddr lo
				o3 := uint32(0x7fe903a6)     // mtctr
				o4 := uint32(0x4e800420)     // bctr
				ld.SysArch.ByteOrder.PutUint32(tramp.P, o1)
				ld.SysArch.ByteOrder.PutUint32(tramp.P[4:], o2)
				ld.SysArch.ByteOrder.PutUint32(tramp.P[8:], o3)
				ld.SysArch.ByteOrder.PutUint32(tramp.P[12:], o4)
			}
			r.Sym = tramp
			r.Add = 0 // This was folded into the trampoline target address
			r.Done = 0
		}
	default:
		ld.Errorf(s, "trampoline called with non-jump reloc: %v", r.Type)
	}
}
예제 #24
0
파일: asm.go 프로젝트: achanda/go
func machoreloc1(s *ld.Symbol, 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/internal/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.Errorf(s, "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.Errorf(s, "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.Errorf(s, "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
}
예제 #25
0
파일: asm.go 프로젝트: kuangchanglang/go
func archreloc(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		switch r.Type {
		case obj.R_CALLARM:
			r.Done = 0

			// set up addend for eventual relocation via outer symbol.
			rs := r.Sym

			r.Xadd = int64(signext24(r.Add & 0xffffff))
			r.Xadd *= 4
			for rs.Outer != nil {
				r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
				rs = rs.Outer
			}

			if rs.Type != obj.SHOSTOBJ && rs.Type != obj.SDYNIMPORT && rs.Sect == nil {
				ld.Errorf(s, "missing section for %s", rs.Name)
			}
			r.Xsym = rs

			// ld64 for arm seems to want the symbol table to contain offset
			// into the section rather than pseudo virtual address that contains
			// the section load address.
			// we need to compensate that by removing the instruction's address
			// from addend.
			if ld.Headtype == obj.Hdarwin {
				r.Xadd -= ld.Symaddr(s) + int64(r.Off)
			}

			if r.Xadd/4 > 0x7fffff || r.Xadd/4 < -0x800000 {
				ld.Errorf(s, "direct call too far %d", r.Xadd/4)
			}

			*val = int64(braddoff(int32(0xff000000&uint32(r.Add)), int32(0xffffff&uint32(r.Xadd/4))))
			return 0
		}

		return -1
	}

	switch r.Type {
	case obj.R_CONST:
		*val = r.Add
		return 0

	case obj.R_GOTOFF:
		*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ctxt.Syms.Lookup(".got", 0))
		return 0

	// The following three arch specific relocations are only for generation of
	// Linux/ARM ELF's PLT entry (3 assembler instruction)
	case obj.R_PLT0: // add ip, pc, #0xXX00000
		if ld.Symaddr(ctxt.Syms.Lookup(".got.plt", 0)) < ld.Symaddr(ctxt.Syms.Lookup(".plt", 0)) {
			ld.Errorf(s, ".got.plt should be placed after .plt section.")
		}
		*val = 0xe28fc600 + (0xff & (int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ctxt.Syms.Lookup(".plt", 0))+int64(r.Off))+r.Add)) >> 20))
		return 0

	case obj.R_PLT1: // add ip, ip, #0xYY000
		*val = 0xe28cca00 + (0xff & (int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ctxt.Syms.Lookup(".plt", 0))+int64(r.Off))+r.Add+4)) >> 12))

		return 0

	case obj.R_PLT2: // ldr pc, [ip, #0xZZZ]!
		*val = 0xe5bcf000 + (0xfff & int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ctxt.Syms.Lookup(".plt", 0))+int64(r.Off))+r.Add+8)))

		return 0

	case obj.R_CALLARM: // bl XXXXXX or b YYYYYY
		// r.Add is the instruction
		// low 24-bit encodes the target address
		t := (ld.Symaddr(r.Sym) + int64(signext24(r.Add&0xffffff)*4) - (s.Value + int64(r.Off))) / 4
		if t > 0x7fffff || t < -0x800000 {
			ld.Errorf(s, "direct call too far: %s %x", r.Sym.Name, t)
		}
		*val = int64(braddoff(int32(0xff000000&uint32(r.Add)), int32(0xffffff&t)))

		return 0
	}

	return -1
}
예제 #26
0
파일: asm.go 프로젝트: achanda/go
func addpltsym(ctxt *ld.Link, s *ld.Symbol) {
	if s.Plt >= 0 {
		return
	}

	ld.Adddynsym(ctxt, s)

	if ld.Iself {
		plt := ctxt.Syms.Lookup(".plt", 0)
		got := ctxt.Syms.Lookup(".got.plt", 0)
		rela := ctxt.Syms.Lookup(".rela.plt", 0)
		if plt.Size == 0 {
			elfsetupplt(ctxt)
		}

		// jmpq *got+size(IP)
		ld.Adduint8(ctxt, plt, 0xff)

		ld.Adduint8(ctxt, plt, 0x25)
		ld.Addpcrelplus(ctxt, plt, got, got.Size)

		// add to got: pointer to current pos in plt
		ld.Addaddrplus(ctxt, got, plt, plt.Size)

		// pushq $x
		ld.Adduint8(ctxt, plt, 0x68)

		ld.Adduint32(ctxt, plt, uint32((got.Size-24-8)/8))

		// jmpq .plt
		ld.Adduint8(ctxt, plt, 0xe9)

		ld.Adduint32(ctxt, plt, uint32(-(plt.Size + 4)))

		// rela
		ld.Addaddrplus(ctxt, rela, got, got.Size-8)

		ld.Adduint64(ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_X86_64_JMP_SLOT))
		ld.Adduint64(ctxt, rela, 0)

		s.Plt = int32(plt.Size - 16)
	} else if ld.Headtype == obj.Hdarwin {
		// To do lazy symbol lookup right, we're supposed
		// to tell the dynamic loader which library each
		// symbol comes from and format the link info
		// section just so. I'm too lazy (ha!) to do that
		// so for now we'll just use non-lazy pointers,
		// which don't need to be told which library to use.
		//
		// http://networkpx.blogspot.com/2009/09/about-lcdyldinfoonly-command.html
		// has details about what we're avoiding.

		addgotsym(ctxt, s)
		plt := ctxt.Syms.Lookup(".plt", 0)

		ld.Adduint32(ctxt, ctxt.Syms.Lookup(".linkedit.plt", 0), uint32(s.Dynid))

		// jmpq *got+size(IP)
		s.Plt = int32(plt.Size)

		ld.Adduint8(ctxt, plt, 0xff)
		ld.Adduint8(ctxt, plt, 0x25)
		ld.Addpcrelplus(ctxt, plt, ctxt.Syms.Lookup(".got", 0), int64(s.Got))
	} else {
		ld.Errorf(s, "addpltsym: unsupported binary format")
	}
}
예제 #27
0
파일: asm.go 프로젝트: kuangchanglang/go
func machoreloc1(s *ld.Symbol, r *ld.Reloc, sectoff int64) int {
	var v uint32

	rs := r.Xsym

	if r.Type == obj.R_PCREL {
		if rs.Type == obj.SHOSTOBJ {
			ld.Errorf(s, "pc-relative relocation of external symbol is not supported")
			return -1
		}
		if r.Siz != 4 {
			return -1
		}

		// emit a pair of "scattered" relocations that
		// resolve to the difference of section addresses of
		// the symbol and the instruction
		// this value is added to the field being relocated
		o1 := uint32(sectoff)
		o1 |= 1 << 31 // scattered bit
		o1 |= ld.MACHO_ARM_RELOC_SECTDIFF << 24
		o1 |= 2 << 28 // size = 4

		o2 := uint32(0)
		o2 |= 1 << 31 // scattered bit
		o2 |= ld.MACHO_ARM_RELOC_PAIR << 24
		o2 |= 2 << 28 // size = 4

		ld.Thearch.Lput(o1)
		ld.Thearch.Lput(uint32(ld.Symaddr(rs)))
		ld.Thearch.Lput(o2)
		ld.Thearch.Lput(uint32(s.Value + int64(r.Off)))
		return 0
	}

	if rs.Type == obj.SHOSTOBJ || r.Type == obj.R_CALLARM {
		if rs.Dynid < 0 {
			ld.Errorf(s, "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.Errorf(s, "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_GENERIC_RELOC_VANILLA << 28

	case obj.R_CALLARM:
		v |= 1 << 24 // pc-relative bit
		v |= ld.MACHO_ARM_RELOC_BR24 << 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
}
예제 #28
0
파일: asm.go 프로젝트: kuangchanglang/go
func adddynrel(ctxt *ld.Link, s *ld.Symbol, r *ld.Reloc) bool {
	targ := r.Sym

	switch r.Type {
	default:
		if r.Type >= 256 {
			ld.Errorf(s, "unexpected relocation type %d", r.Type)
			return false
		}

		// Handle relocations found in ELF object files.
	case 256 + ld.R_ARM_PLT32:
		r.Type = obj.R_CALLARM

		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ctxt, targ)
			r.Sym = ctxt.Syms.Lookup(".plt", 0)
			r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
		}

		return true

	case 256 + ld.R_ARM_THM_PC22: // R_ARM_THM_CALL
		ld.Exitf("R_ARM_THM_CALL, are you using -marm?")
		return false

	case 256 + ld.R_ARM_GOT32: // R_ARM_GOT_BREL
		if targ.Type != obj.SDYNIMPORT {
			addgotsyminternal(ctxt, targ)
		} else {
			addgotsym(ctxt, targ)
		}

		r.Type = obj.R_CONST // write r->add during relocsym
		r.Sym = nil
		r.Add += int64(targ.Got)
		return true

	case 256 + ld.R_ARM_GOT_PREL: // GOT(nil) + A - nil
		if targ.Type != obj.SDYNIMPORT {
			addgotsyminternal(ctxt, targ)
		} else {
			addgotsym(ctxt, targ)
		}

		r.Type = obj.R_PCREL
		r.Sym = ctxt.Syms.Lookup(".got", 0)
		r.Add += int64(targ.Got) + 4
		return true

	case 256 + ld.R_ARM_GOTOFF: // R_ARM_GOTOFF32
		r.Type = obj.R_GOTOFF

		return true

	case 256 + ld.R_ARM_GOTPC: // R_ARM_BASE_PREL
		r.Type = obj.R_PCREL

		r.Sym = ctxt.Syms.Lookup(".got", 0)
		r.Add += 4
		return true

	case 256 + ld.R_ARM_CALL:
		r.Type = obj.R_CALLARM
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ctxt, targ)
			r.Sym = ctxt.Syms.Lookup(".plt", 0)
			r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
		}

		return true

	case 256 + ld.R_ARM_REL32: // R_ARM_REL32
		r.Type = obj.R_PCREL

		r.Add += 4
		return true

	case 256 + ld.R_ARM_ABS32:
		if targ.Type == obj.SDYNIMPORT {
			ld.Errorf(s, "unexpected R_ARM_ABS32 relocation for dynamic symbol %s", targ.Name)
		}
		r.Type = obj.R_ADDR
		return true

		// we can just ignore this, because we are targeting ARM V5+ anyway
	case 256 + ld.R_ARM_V4BX:
		if r.Sym != nil {
			// R_ARM_V4BX is ABS relocation, so this symbol is a dummy symbol, ignore it
			r.Sym.Type = 0
		}

		r.Sym = nil
		return true

	case 256 + ld.R_ARM_PC24,
		256 + ld.R_ARM_JUMP24:
		r.Type = obj.R_CALLARM
		if targ.Type == obj.SDYNIMPORT {
			addpltsym(ctxt, targ)
			r.Sym = ctxt.Syms.Lookup(".plt", 0)
			r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
		}

		return true
	}

	// Handle references to ELF symbols from our own object files.
	if targ.Type != obj.SDYNIMPORT {
		return true
	}

	switch r.Type {
	case obj.R_CALLARM:
		addpltsym(ctxt, targ)
		r.Sym = ctxt.Syms.Lookup(".plt", 0)
		r.Add = int64(targ.Plt)
		return true

	case obj.R_ADDR:
		if s.Type != obj.SDATA {
			break
		}
		if ld.Iself {
			ld.Adddynsym(ctxt, targ)
			rel := ctxt.Syms.Lookup(".rel", 0)
			ld.Addaddrplus(ctxt, rel, s, int64(r.Off))
			ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(targ.Dynid), ld.R_ARM_GLOB_DAT)) // we need a nil + A dynamic reloc
			r.Type = obj.R_CONST                                                            // write r->add during relocsym
			r.Sym = nil
			return true
		}
	}

	return false
}
예제 #29
0
파일: asm.go 프로젝트: achanda/go
func archreloc(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol, val *int64) int {
	if ld.Linkmode == ld.LinkExternal {
		switch r.Type {
		default:
			return -1

		case obj.R_ARM64_GOTPCREL:
			var o1, o2 uint32
			if ctxt.Arch.ByteOrder == binary.BigEndian {
				o1 = uint32(*val >> 32)
				o2 = uint32(*val)
			} else {
				o1 = uint32(*val)
				o2 = uint32(*val >> 32)
			}
			// Any relocation against a function symbol is redirected to
			// be against a local symbol instead (see putelfsym in
			// symtab.go) but unfortunately the system linker was buggy
			// when confronted with a R_AARCH64_ADR_GOT_PAGE relocation
			// against a local symbol until May 2015
			// (https://sourceware.org/bugzilla/show_bug.cgi?id=18270). So
			// we convert the adrp; ld64 + R_ARM64_GOTPCREL into adrp;
			// add + R_ADDRARM64.
			if !(r.Sym.Version != 0 || (r.Sym.Type&obj.SHIDDEN != 0) || r.Sym.Attr.Local()) && r.Sym.Type == obj.STEXT && ctxt.DynlinkingGo() {
				if o2&0xffc00000 != 0xf9400000 {
					ld.Errorf(s, "R_ARM64_GOTPCREL against unexpected instruction %x", o2)
				}
				o2 = 0x91000000 | (o2 & 0x000003ff)
				r.Type = obj.R_ADDRARM64
			}
			if ctxt.Arch.ByteOrder == binary.BigEndian {
				*val = int64(o1)<<32 | int64(o2)
			} else {
				*val = int64(o2)<<32 | int64(o1)
			}
			fallthrough

		case obj.R_ADDRARM64:
			r.Done = 0

			// set up addend for eventual relocation via outer symbol.
			rs := r.Sym
			r.Xadd = r.Add
			for rs.Outer != nil {
				r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
				rs = rs.Outer
			}

			if rs.Type != obj.SHOSTOBJ && rs.Type != obj.SDYNIMPORT && rs.Sect == nil {
				ld.Errorf(s, "missing section for %s", rs.Name)
			}
			r.Xsym = rs

			// Note: ld64 currently has a bug that any non-zero addend for BR26 relocation
			// will make the linking fail because it thinks the code is not PIC even though
			// the BR26 relocation should be fully resolved at link time.
			// That is the reason why the next if block is disabled. When the bug in ld64
			// is fixed, we can enable this block and also enable duff's device in cmd/7g.
			if false && ld.Headtype == obj.Hdarwin {
				var o0, o1 uint32

				if ctxt.Arch.ByteOrder == binary.BigEndian {
					o0 = uint32(*val >> 32)
					o1 = uint32(*val)
				} else {
					o0 = uint32(*val)
					o1 = uint32(*val >> 32)
				}
				// Mach-O wants the addend to be encoded in the instruction
				// Note that although Mach-O supports ARM64_RELOC_ADDEND, it
				// can only encode 24-bit of signed addend, but the instructions
				// supports 33-bit of signed addend, so we always encode the
				// addend in place.
				o0 |= (uint32((r.Xadd>>12)&3) << 29) | (uint32((r.Xadd>>12>>2)&0x7ffff) << 5)
				o1 |= uint32(r.Xadd&0xfff) << 10
				r.Xadd = 0

				// when laid out, the instruction order must always be o1, o2.
				if ctxt.Arch.ByteOrder == binary.BigEndian {
					*val = int64(o0)<<32 | int64(o1)
				} else {
					*val = int64(o1)<<32 | int64(o0)
				}
			}

			return 0

		case obj.R_CALLARM64,
			obj.R_ARM64_TLS_LE,
			obj.R_ARM64_TLS_IE:
			r.Done = 0
			r.Xsym = r.Sym
			r.Xadd = r.Add
			return 0
		}
	}

	switch r.Type {
	case obj.R_CONST:
		*val = r.Add
		return 0

	case obj.R_GOTOFF:
		*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ctxt.Syms.Lookup(".got", 0))
		return 0

	case obj.R_ADDRARM64:
		t := ld.Symaddr(r.Sym) + r.Add - ((s.Value + int64(r.Off)) &^ 0xfff)
		if t >= 1<<32 || t < -1<<32 {
			ld.Errorf(s, "program too large, address relocation distance = %d", t)
		}

		var o0, o1 uint32

		if ctxt.Arch.ByteOrder == binary.BigEndian {
			o0 = uint32(*val >> 32)
			o1 = uint32(*val)
		} else {
			o0 = uint32(*val)
			o1 = uint32(*val >> 32)
		}

		o0 |= (uint32((t>>12)&3) << 29) | (uint32((t>>12>>2)&0x7ffff) << 5)
		o1 |= uint32(t&0xfff) << 10

		// when laid out, the instruction order must always be o1, o2.
		if ctxt.Arch.ByteOrder == binary.BigEndian {
			*val = int64(o0)<<32 | int64(o1)
		} else {
			*val = int64(o1)<<32 | int64(o0)
		}
		return 0

	case obj.R_ARM64_TLS_LE:
		r.Done = 0
		if ld.Headtype != obj.Hlinux {
			ld.Errorf(s, "TLS reloc on unsupported OS %v", ld.Headtype)
		}
		// The TCB is two pointers. This is not documented anywhere, but is
		// de facto part of the ABI.
		v := r.Sym.Value + int64(2*ld.SysArch.PtrSize)
		if v < 0 || v >= 32678 {
			ld.Errorf(s, "TLS offset out of range %d", v)
		}
		*val |= v << 5
		return 0

	case obj.R_CALLARM64:
		t := (ld.Symaddr(r.Sym) + r.Add) - (s.Value + int64(r.Off))
		if t >= 1<<27 || t < -1<<27 {
			ld.Errorf(s, "program too large, call relocation distance = %d", t)
		}
		*val |= (t >> 2) & 0x03ffffff
		return 0
	}

	return -1
}
예제 #30
0
파일: asm.go 프로젝트: achanda/go
func asmb(ctxt *ld.Link) {
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f asmb\n", obj.Cputime())
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f codeblk\n", obj.Cputime())
	}

	if ld.Iself {
		ld.Asmbelfsetup()
	}

	sect := ld.Segtext.Sect
	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
	// 0xCC is INT $3 - breakpoint instruction
	ld.CodeblkPad(ctxt, int64(sect.Vaddr), int64(sect.Length), []byte{0xCC})
	for sect = sect.Next; sect != nil; sect = sect.Next {
		ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
		ld.Datblk(ctxt, int64(sect.Vaddr), int64(sect.Length))
	}

	if ld.Segrodata.Filelen > 0 {
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f rodatblk\n", obj.Cputime())
		}
		ld.Cseek(int64(ld.Segrodata.Fileoff))
		ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
	}
	if ld.Segrelrodata.Filelen > 0 {
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f relrodatblk\n", obj.Cputime())
		}
		ld.Cseek(int64(ld.Segrelrodata.Fileoff))
		ld.Datblk(ctxt, int64(ld.Segrelrodata.Vaddr), int64(ld.Segrelrodata.Filelen))
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f datblk\n", obj.Cputime())
	}

	ld.Cseek(int64(ld.Segdata.Fileoff))
	ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))

	ld.Cseek(int64(ld.Segdwarf.Fileoff))
	ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen))

	machlink := int64(0)
	if ld.Headtype == obj.Hdarwin {
		machlink = ld.Domacholink(ctxt)
	}

	switch ld.Headtype {
	default:
		ld.Errorf(nil, "unknown header type %v", ld.Headtype)
		fallthrough

	case obj.Hplan9:
		break

	case obj.Hdarwin:
		ld.Flag8 = true /* 64-bit addresses */

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hdragonfly,
		obj.Hsolaris:
		ld.Flag8 = true /* 64-bit addresses */

	case obj.Hnacl,
		obj.Hwindows,
		obj.Hwindowsgui:
		break
	}

	ld.Symsize = 0
	ld.Spsize = 0
	ld.Lcsize = 0
	symo := int64(0)
	if !*ld.FlagS {
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f sym\n", obj.Cputime())
		}
		switch ld.Headtype {
		default:
		case obj.Hplan9:
			*ld.FlagS = true
			symo = int64(ld.Segdata.Fileoff + ld.Segdata.Filelen)

		case obj.Hdarwin:
			symo = int64(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(*ld.FlagRound))) + uint64(machlink))

		case obj.Hlinux,
			obj.Hfreebsd,
			obj.Hnetbsd,
			obj.Hopenbsd,
			obj.Hdragonfly,
			obj.Hsolaris,
			obj.Hnacl:
			symo = int64(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
			symo = ld.Rnd(symo, int64(*ld.FlagRound))

		case obj.Hwindows,
			obj.Hwindowsgui:
			symo = int64(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
			symo = ld.Rnd(symo, ld.PEFILEALIGN)
		}

		ld.Cseek(symo)
		switch ld.Headtype {
		default:
			if ld.Iself {
				ld.Cseek(symo)
				ld.Asmelfsym(ctxt)
				ld.Cflush()
				ld.Cwrite(ld.Elfstrdat)

				if ctxt.Debugvlog != 0 {
					ctxt.Logf("%5.2f dwarf\n", obj.Cputime())
				}

				if ld.Linkmode == ld.LinkExternal {
					ld.Elfemitreloc(ctxt)
				}
			}

		case obj.Hplan9:
			ld.Asmplan9sym(ctxt)
			ld.Cflush()

			sym := ctxt.Syms.Lookup("pclntab", 0)
			if sym != nil {
				ld.Lcsize = int32(len(sym.P))
				for i := 0; int32(i) < ld.Lcsize; i++ {
					ld.Cput(sym.P[i])
				}

				ld.Cflush()
			}

		case obj.Hwindows, obj.Hwindowsgui:
			if ctxt.Debugvlog != 0 {
				ctxt.Logf("%5.2f dwarf\n", obj.Cputime())
			}

		case obj.Hdarwin:
			if ld.Linkmode == ld.LinkExternal {
				ld.Machoemitreloc(ctxt)
			}
		}
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f headr\n", obj.Cputime())
	}
	ld.Cseek(0)
	switch ld.Headtype {
	default:
	case obj.Hplan9: /* plan9 */
		magic := int32(4*26*26 + 7)

		magic |= 0x00008000                  /* fat header */
		ld.Lputb(uint32(magic))              /* magic */
		ld.Lputb(uint32(ld.Segtext.Filelen)) /* sizes */
		ld.Lputb(uint32(ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Symsize)) /* nsyms */
		vl := ld.Entryvalue(ctxt)
		ld.Lputb(PADDR(uint32(vl))) /* va of entry */
		ld.Lputb(uint32(ld.Spsize)) /* sp offsets */
		ld.Lputb(uint32(ld.Lcsize)) /* line offsets */
		ld.Vputb(uint64(vl))        /* va of entry */

	case obj.Hdarwin:
		ld.Asmbmacho(ctxt)

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hdragonfly,
		obj.Hsolaris,
		obj.Hnacl:
		ld.Asmbelf(ctxt, symo)

	case obj.Hwindows,
		obj.Hwindowsgui:
		ld.Asmbpe(ctxt)
	}

	ld.Cflush()
}