| // Inferno utils/6l/asm.c |
| // https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/asm.c |
| // |
| // Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. |
| // Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net) |
| // Portions Copyright © 1997-1999 Vita Nuova Limited |
| // Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com) |
| // Portions Copyright © 2004,2006 Bruce Ellis |
| // Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net) |
| // Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others |
| // Portions Copyright © 2009 The Go Authors. All rights reserved. |
| // |
| // Permission is hereby granted, free of charge, to any person obtaining a copy |
| // of this software and associated documentation files (the "Software"), to deal |
| // in the Software without restriction, including without limitation the rights |
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| // copies of the Software, and to permit persons to whom the Software is |
| // furnished to do so, subject to the following conditions: |
| // |
| // The above copyright notice and this permission notice shall be included in |
| // all copies or substantial portions of the Software. |
| // |
| // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| // THE SOFTWARE. |
| |
| package amd64 |
| |
| import ( |
| "cmd/internal/objabi" |
| "cmd/internal/sys" |
| "cmd/link/internal/ld" |
| "cmd/link/internal/sym" |
| "debug/elf" |
| "log" |
| ) |
| |
| func PADDR(x uint32) uint32 { |
| return x &^ 0x80000000 |
| } |
| |
| func Addcall(ctxt *ld.Link, s *sym.Symbol, t *sym.Symbol) int64 { |
| s.Attr |= sym.AttrReachable |
| i := s.Size |
| s.Size += 4 |
| s.Grow(s.Size) |
| r := s.AddRel() |
| r.Sym = t |
| r.Off = int32(i) |
| r.Type = objabi.R_CALL |
| r.Siz = 4 |
| return i + int64(r.Siz) |
| } |
| |
| func gentext(ctxt *ld.Link) { |
| if !ctxt.DynlinkingGo() { |
| return |
| } |
| addmoduledata := ctxt.Syms.Lookup("runtime.addmoduledata", 0) |
| if addmoduledata.Type == sym.STEXT && ctxt.BuildMode != ld.BuildModePlugin { |
| // we're linking a module containing the runtime -> no need for |
| // an init function |
| return |
| } |
| addmoduledata.Attr |= sym.AttrReachable |
| initfunc := ctxt.Syms.Lookup("go.link.addmoduledata", 0) |
| initfunc.Type = sym.STEXT |
| initfunc.Attr |= sym.AttrLocal |
| initfunc.Attr |= sym.AttrReachable |
| o := func(op ...uint8) { |
| for _, op1 := range op { |
| initfunc.AddUint8(op1) |
| } |
| } |
| // 0000000000000000 <local.dso_init>: |
| // 0: 48 8d 3d 00 00 00 00 lea 0x0(%rip),%rdi # 7 <local.dso_init+0x7> |
| // 3: R_X86_64_PC32 runtime.firstmoduledata-0x4 |
| o(0x48, 0x8d, 0x3d) |
| initfunc.AddPCRelPlus(ctxt.Arch, ctxt.Moduledata, 0) |
| // 7: e8 00 00 00 00 callq c <local.dso_init+0xc> |
| // 8: R_X86_64_PLT32 runtime.addmoduledata-0x4 |
| o(0xe8) |
| Addcall(ctxt, initfunc, addmoduledata) |
| // c: c3 retq |
| o(0xc3) |
| if ctxt.BuildMode == ld.BuildModePlugin { |
| ctxt.Textp = append(ctxt.Textp, addmoduledata) |
| } |
| ctxt.Textp = append(ctxt.Textp, initfunc) |
| initarray_entry := ctxt.Syms.Lookup("go.link.addmoduledatainit", 0) |
| initarray_entry.Attr |= sym.AttrReachable |
| initarray_entry.Attr |= sym.AttrLocal |
| initarray_entry.Type = sym.SINITARR |
| initarray_entry.AddAddr(ctxt.Arch, initfunc) |
| } |
| |
| func adddynrel(ctxt *ld.Link, s *sym.Symbol, r *sym.Reloc) bool { |
| targ := r.Sym |
| |
| switch r.Type { |
| default: |
| if r.Type >= objabi.ElfRelocOffset { |
| ld.Errorf(s, "unexpected relocation type %d (%s)", r.Type, sym.RelocName(ctxt.Arch, r.Type)) |
| return false |
| } |
| |
| // Handle relocations found in ELF object files. |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_PC32): |
| if targ.Type == sym.SDYNIMPORT { |
| ld.Errorf(s, "unexpected R_X86_64_PC32 relocation for dynamic symbol %s", targ.Name) |
| } |
| // TODO(mwhudson): the test of VisibilityHidden here probably doesn't make |
| // sense and should be removed when someone has thought about it properly. |
| if (targ.Type == 0 || targ.Type == sym.SXREF) && !targ.Attr.VisibilityHidden() { |
| ld.Errorf(s, "unknown symbol %s in pcrel", targ.Name) |
| } |
| r.Type = objabi.R_PCREL |
| r.Add += 4 |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_PC64): |
| if targ.Type == sym.SDYNIMPORT { |
| ld.Errorf(s, "unexpected R_X86_64_PC64 relocation for dynamic symbol %s", targ.Name) |
| } |
| if targ.Type == 0 || targ.Type == sym.SXREF { |
| ld.Errorf(s, "unknown symbol %s in pcrel", targ.Name) |
| } |
| r.Type = objabi.R_PCREL |
| r.Add += 8 |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_PLT32): |
| r.Type = objabi.R_PCREL |
| r.Add += 4 |
| if targ.Type == sym.SDYNIMPORT { |
| addpltsym(ctxt, targ) |
| r.Sym = ctxt.Syms.Lookup(".plt", 0) |
| r.Add += int64(targ.Plt()) |
| } |
| |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_GOTPCREL), |
| objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_GOTPCRELX), |
| objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_REX_GOTPCRELX): |
| if targ.Type != sym.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 = objabi.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 = objabi.R_PCREL |
| r.Sym = ctxt.Syms.Lookup(".got", 0) |
| r.Add += 4 |
| r.Add += int64(targ.Got()) |
| return true |
| |
| case objabi.ElfRelocOffset + objabi.RelocType(elf.R_X86_64_64): |
| if targ.Type == sym.SDYNIMPORT { |
| ld.Errorf(s, "unexpected R_X86_64_64 relocation for dynamic symbol %s", targ.Name) |
| } |
| r.Type = objabi.R_ADDR |
| return true |
| |
| // Handle relocations found in Mach-O object files. |
| case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_UNSIGNED*2 + 0, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_SIGNED*2 + 0, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_BRANCH*2 + 0: |
| // TODO: What is the difference between all these? |
| r.Type = objabi.R_ADDR |
| |
| if targ.Type == sym.SDYNIMPORT { |
| ld.Errorf(s, "unexpected reloc for dynamic symbol %s", targ.Name) |
| } |
| return true |
| |
| case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_BRANCH*2 + 1: |
| if targ.Type == sym.SDYNIMPORT { |
| addpltsym(ctxt, targ) |
| r.Sym = ctxt.Syms.Lookup(".plt", 0) |
| r.Add = int64(targ.Plt()) |
| r.Type = objabi.R_PCREL |
| return true |
| } |
| fallthrough |
| |
| case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_UNSIGNED*2 + 1, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_SIGNED*2 + 1, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_SIGNED_1*2 + 1, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_SIGNED_2*2 + 1, |
| objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_SIGNED_4*2 + 1: |
| r.Type = objabi.R_PCREL |
| |
| if targ.Type == sym.SDYNIMPORT { |
| ld.Errorf(s, "unexpected pc-relative reloc for dynamic symbol %s", targ.Name) |
| } |
| return true |
| |
| case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_GOT_LOAD*2 + 1: |
| if targ.Type != sym.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 = objabi.R_PCREL |
| return true |
| } |
| fallthrough |
| |
| case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_GOT*2 + 1: |
| if targ.Type != sym.SDYNIMPORT { |
| ld.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", targ.Name) |
| } |
| addgotsym(ctxt, targ) |
| r.Type = objabi.R_PCREL |
| r.Sym = ctxt.Syms.Lookup(".got", 0) |
| r.Add += int64(targ.Got()) |
| return true |
| } |
| |
| switch r.Type { |
| case objabi.R_CALL, |
| objabi.R_PCREL: |
| if targ.Type != sym.SDYNIMPORT { |
| // nothing to do, the relocation will be laid out in reloc |
| return true |
| } |
| if ctxt.LinkMode == ld.LinkExternal { |
| // External linker will do this relocation. |
| return true |
| } |
| // Internal linking, for both ELF and Mach-O. |
| // Build a PLT entry and change the relocation target to that entry. |
| addpltsym(ctxt, targ) |
| r.Sym = ctxt.Syms.Lookup(".plt", 0) |
| r.Add = int64(targ.Plt()) |
| return true |
| |
| case objabi.R_ADDR: |
| if s.Type == sym.STEXT && ctxt.IsELF { |
| if ctxt.HeadType == objabi.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 ctxt.BuildMode == ld.BuildModePIE && ctxt.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. |
| // |
| // Furthermore, the rela sections contain dynamic |
| // relocations with R_ADDR relocations on |
| // Elf64_Rela.r_offset. This field should contain the |
| // symbol offset as determined by reloc(), not the |
| // final dynamically linked address as a dynamic |
| // relocation would provide. |
| switch s.Name { |
| case ".dynsym", ".rela", ".rela.plt", ".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 != sym.SDATA && s.Type != sym.SRODATA { |
| break |
| } |
| } |
| |
| if ctxt.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) |
| rela.AddAddrPlus(ctxt.Arch, s, int64(r.Off)) |
| if r.Siz == 8 { |
| rela.AddUint64(ctxt.Arch, ld.ELF64_R_INFO(uint32(targ.Dynid), uint32(elf.R_X86_64_64))) |
| } else { |
| // TODO: never happens, remove. |
| rela.AddUint64(ctxt.Arch, ld.ELF64_R_INFO(uint32(targ.Dynid), uint32(elf.R_X86_64_32))) |
| } |
| rela.AddUint64(ctxt.Arch, uint64(r.Add)) |
| r.Type = objabi.ElfRelocOffset // ignore during relocsym |
| return true |
| } |
| |
| if ctxt.HeadType == objabi.Hdarwin && s.Size == int64(ctxt.Arch.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 |
| s.Attr |= sym.AttrSubSymbol |
| s.Outer = got |
| s.Sub = got.Sub |
| got.Sub = s |
| s.Value = got.Size |
| got.AddUint64(ctxt.Arch, 0) |
| ctxt.Syms.Lookup(".linkedit.got", 0).AddUint32(ctxt.Arch, uint32(targ.Dynid)) |
| r.Type = objabi.ElfRelocOffset // ignore during relocsym |
| return true |
| } |
| } |
| |
| return false |
| } |
| |
| func elfreloc1(ctxt *ld.Link, r *sym.Reloc, sectoff int64) bool { |
| ctxt.Out.Write64(uint64(sectoff)) |
| |
| elfsym := r.Xsym.ElfsymForReloc() |
| switch r.Type { |
| default: |
| return false |
| case objabi.R_ADDR: |
| if r.Siz == 4 { |
| ctxt.Out.Write64(uint64(elf.R_X86_64_32) | uint64(elfsym)<<32) |
| } else if r.Siz == 8 { |
| ctxt.Out.Write64(uint64(elf.R_X86_64_64) | uint64(elfsym)<<32) |
| } else { |
| return false |
| } |
| case objabi.R_TLS_LE: |
| if r.Siz == 4 { |
| ctxt.Out.Write64(uint64(elf.R_X86_64_TPOFF32) | uint64(elfsym)<<32) |
| } else { |
| return false |
| } |
| case objabi.R_TLS_IE: |
| if r.Siz == 4 { |
| ctxt.Out.Write64(uint64(elf.R_X86_64_GOTTPOFF) | uint64(elfsym)<<32) |
| } else { |
| return false |
| } |
| case objabi.R_CALL: |
| if r.Siz == 4 { |
| if r.Xsym.Type == sym.SDYNIMPORT { |
| if ctxt.DynlinkingGo() { |
| ctxt.Out.Write64(uint64(elf.R_X86_64_PLT32) | uint64(elfsym)<<32) |
| } else { |
| ctxt.Out.Write64(uint64(elf.R_X86_64_GOTPCREL) | uint64(elfsym)<<32) |
| } |
| } else { |
| ctxt.Out.Write64(uint64(elf.R_X86_64_PC32) | uint64(elfsym)<<32) |
| } |
| } else { |
| return false |
| } |
| case objabi.R_PCREL: |
| if r.Siz == 4 { |
| if r.Xsym.Type == sym.SDYNIMPORT && r.Xsym.ElfType() == elf.STT_FUNC { |
| ctxt.Out.Write64(uint64(elf.R_X86_64_PLT32) | uint64(elfsym)<<32) |
| } else { |
| ctxt.Out.Write64(uint64(elf.R_X86_64_PC32) | uint64(elfsym)<<32) |
| } |
| } else { |
| return false |
| } |
| case objabi.R_GOTPCREL: |
| if r.Siz == 4 { |
| ctxt.Out.Write64(uint64(elf.R_X86_64_GOTPCREL) | uint64(elfsym)<<32) |
| } else { |
| return false |
| } |
| } |
| |
| ctxt.Out.Write64(uint64(r.Xadd)) |
| return true |
| } |
| |
| func machoreloc1(arch *sys.Arch, out *ld.OutBuf, s *sym.Symbol, r *sym.Reloc, sectoff int64) bool { |
| var v uint32 |
| |
| rs := r.Xsym |
| |
| if rs.Type == sym.SHOSTOBJ || r.Type == objabi.R_PCREL || r.Type == objabi.R_GOTPCREL || r.Type == objabi.R_CALL { |
| if rs.Dynid < 0 { |
| ld.Errorf(s, "reloc %d (%s) to non-macho symbol %s type=%d (%s)", r.Type, sym.RelocName(arch, r.Type), rs.Name, rs.Type, rs.Type) |
| return false |
| } |
| |
| v = uint32(rs.Dynid) |
| v |= 1 << 27 // external relocation |
| } else { |
| v = uint32(rs.Sect.Extnum) |
| if v == 0 { |
| ld.Errorf(s, "reloc %d (%s) to symbol %s in non-macho section %s type=%d (%s)", r.Type, sym.RelocName(arch, r.Type), rs.Name, rs.Sect.Name, rs.Type, rs.Type) |
| return false |
| } |
| } |
| |
| switch r.Type { |
| default: |
| return false |
| |
| case objabi.R_ADDR: |
| v |= ld.MACHO_X86_64_RELOC_UNSIGNED << 28 |
| |
| case objabi.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 objabi.R_PCREL: |
| v |= 1 << 24 // pc-relative bit |
| v |= ld.MACHO_X86_64_RELOC_SIGNED << 28 |
| case objabi.R_GOTPCREL: |
| v |= 1 << 24 // pc-relative bit |
| v |= ld.MACHO_X86_64_RELOC_GOT_LOAD << 28 |
| } |
| |
| switch r.Siz { |
| default: |
| return false |
| |
| case 1: |
| v |= 0 << 25 |
| |
| case 2: |
| v |= 1 << 25 |
| |
| case 4: |
| v |= 2 << 25 |
| |
| case 8: |
| v |= 3 << 25 |
| } |
| |
| out.Write32(uint32(sectoff)) |
| out.Write32(v) |
| return true |
| } |
| |
| func pereloc1(arch *sys.Arch, out *ld.OutBuf, s *sym.Symbol, r *sym.Reloc, sectoff int64) bool { |
| var v uint32 |
| |
| rs := r.Xsym |
| |
| if rs.Dynid < 0 { |
| ld.Errorf(s, "reloc %d (%s) to non-coff symbol %s type=%d (%s)", r.Type, sym.RelocName(arch, r.Type), rs.Name, rs.Type, rs.Type) |
| return false |
| } |
| |
| out.Write32(uint32(sectoff)) |
| out.Write32(uint32(rs.Dynid)) |
| |
| switch r.Type { |
| default: |
| return false |
| |
| case objabi.R_DWARFSECREF: |
| v = ld.IMAGE_REL_AMD64_SECREL |
| |
| case objabi.R_ADDR: |
| if r.Siz == 8 { |
| v = ld.IMAGE_REL_AMD64_ADDR64 |
| } else { |
| v = ld.IMAGE_REL_AMD64_ADDR32 |
| } |
| |
| case objabi.R_CALL, |
| objabi.R_PCREL: |
| v = ld.IMAGE_REL_AMD64_REL32 |
| } |
| |
| out.Write16(uint16(v)) |
| |
| return true |
| } |
| |
| func archreloc(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, val int64) (int64, bool) { |
| return val, false |
| } |
| |
| func archrelocvariant(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, t int64) int64 { |
| log.Fatalf("unexpected relocation variant") |
| return t |
| } |
| |
| func elfsetupplt(ctxt *ld.Link) { |
| plt := ctxt.Syms.Lookup(".plt", 0) |
| got := ctxt.Syms.Lookup(".got.plt", 0) |
| if plt.Size == 0 { |
| // pushq got+8(IP) |
| plt.AddUint8(0xff) |
| |
| plt.AddUint8(0x35) |
| plt.AddPCRelPlus(ctxt.Arch, got, 8) |
| |
| // jmpq got+16(IP) |
| plt.AddUint8(0xff) |
| |
| plt.AddUint8(0x25) |
| plt.AddPCRelPlus(ctxt.Arch, got, 16) |
| |
| // nopl 0(AX) |
| plt.AddUint32(ctxt.Arch, 0x00401f0f) |
| |
| // assume got->size == 0 too |
| got.AddAddrPlus(ctxt.Arch, ctxt.Syms.Lookup(".dynamic", 0), 0) |
| |
| got.AddUint64(ctxt.Arch, 0) |
| got.AddUint64(ctxt.Arch, 0) |
| } |
| } |
| |
| func addpltsym(ctxt *ld.Link, s *sym.Symbol) { |
| if s.Plt() >= 0 { |
| return |
| } |
| |
| ld.Adddynsym(ctxt, s) |
| |
| if ctxt.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) |
| plt.AddUint8(0xff) |
| |
| plt.AddUint8(0x25) |
| plt.AddPCRelPlus(ctxt.Arch, got, got.Size) |
| |
| // add to got: pointer to current pos in plt |
| got.AddAddrPlus(ctxt.Arch, plt, plt.Size) |
| |
| // pushq $x |
| plt.AddUint8(0x68) |
| |
| plt.AddUint32(ctxt.Arch, uint32((got.Size-24-8)/8)) |
| |
| // jmpq .plt |
| plt.AddUint8(0xe9) |
| |
| plt.AddUint32(ctxt.Arch, uint32(-(plt.Size + 4))) |
| |
| // rela |
| rela.AddAddrPlus(ctxt.Arch, got, got.Size-8) |
| |
| rela.AddUint64(ctxt.Arch, ld.ELF64_R_INFO(uint32(s.Dynid), uint32(elf.R_X86_64_JMP_SLOT))) |
| rela.AddUint64(ctxt.Arch, 0) |
| |
| s.SetPlt(int32(plt.Size - 16)) |
| } else if ctxt.HeadType == objabi.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. |
| // |
| // https://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) |
| |
| ctxt.Syms.Lookup(".linkedit.plt", 0).AddUint32(ctxt.Arch, uint32(s.Dynid)) |
| |
| // jmpq *got+size(IP) |
| s.SetPlt(int32(plt.Size)) |
| |
| plt.AddUint8(0xff) |
| plt.AddUint8(0x25) |
| plt.AddPCRelPlus(ctxt.Arch, ctxt.Syms.Lookup(".got", 0), int64(s.Got())) |
| } else { |
| ld.Errorf(s, "addpltsym: unsupported binary format") |
| } |
| } |
| |
| func addgotsym(ctxt *ld.Link, s *sym.Symbol) { |
| if s.Got() >= 0 { |
| return |
| } |
| |
| ld.Adddynsym(ctxt, s) |
| got := ctxt.Syms.Lookup(".got", 0) |
| s.SetGot(int32(got.Size)) |
| got.AddUint64(ctxt.Arch, 0) |
| |
| if ctxt.IsELF { |
| rela := ctxt.Syms.Lookup(".rela", 0) |
| rela.AddAddrPlus(ctxt.Arch, got, int64(s.Got())) |
| rela.AddUint64(ctxt.Arch, ld.ELF64_R_INFO(uint32(s.Dynid), uint32(elf.R_X86_64_GLOB_DAT))) |
| rela.AddUint64(ctxt.Arch, 0) |
| } else if ctxt.HeadType == objabi.Hdarwin { |
| ctxt.Syms.Lookup(".linkedit.got", 0).AddUint32(ctxt.Arch, uint32(s.Dynid)) |
| } else { |
| ld.Errorf(s, "addgotsym: unsupported binary format") |
| } |
| } |
| |
| func asmb(ctxt *ld.Link) { |
| if ctxt.IsELF { |
| ld.Asmbelfsetup() |
| } |
| |
| sect := ld.Segtext.Sections[0] |
| ctxt.Out.SeekSet(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 = range ld.Segtext.Sections[1:] { |
| ctxt.Out.SeekSet(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff)) |
| ld.Datblk(ctxt, int64(sect.Vaddr), int64(sect.Length)) |
| } |
| |
| if ld.Segrodata.Filelen > 0 { |
| ctxt.Out.SeekSet(int64(ld.Segrodata.Fileoff)) |
| ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen)) |
| } |
| if ld.Segrelrodata.Filelen > 0 { |
| ctxt.Out.SeekSet(int64(ld.Segrelrodata.Fileoff)) |
| ld.Datblk(ctxt, int64(ld.Segrelrodata.Vaddr), int64(ld.Segrelrodata.Filelen)) |
| } |
| |
| ctxt.Out.SeekSet(int64(ld.Segdata.Fileoff)) |
| ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen)) |
| |
| ctxt.Out.SeekSet(int64(ld.Segdwarf.Fileoff)) |
| ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen)) |
| } |
| |
| func asmb2(ctxt *ld.Link) { |
| machlink := int64(0) |
| if ctxt.HeadType == objabi.Hdarwin { |
| machlink = ld.Domacholink(ctxt) |
| } |
| |
| switch ctxt.HeadType { |
| default: |
| ld.Errorf(nil, "unknown header type %v", ctxt.HeadType) |
| fallthrough |
| |
| case objabi.Hplan9: |
| break |
| |
| case objabi.Hdarwin: |
| ld.Flag8 = true /* 64-bit addresses */ |
| |
| case objabi.Hlinux, |
| objabi.Hfreebsd, |
| objabi.Hnetbsd, |
| objabi.Hopenbsd, |
| objabi.Hdragonfly, |
| objabi.Hsolaris: |
| ld.Flag8 = true /* 64-bit addresses */ |
| |
| case objabi.Hwindows: |
| break |
| } |
| |
| ld.Symsize = 0 |
| ld.Spsize = 0 |
| ld.Lcsize = 0 |
| symo := int64(0) |
| if !*ld.FlagS { |
| switch ctxt.HeadType { |
| default: |
| case objabi.Hplan9: |
| *ld.FlagS = true |
| symo = int64(ld.Segdata.Fileoff + ld.Segdata.Filelen) |
| |
| case objabi.Hdarwin: |
| symo = int64(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(*ld.FlagRound))) + uint64(machlink)) |
| |
| case objabi.Hlinux, |
| objabi.Hfreebsd, |
| objabi.Hnetbsd, |
| objabi.Hopenbsd, |
| objabi.Hdragonfly, |
| objabi.Hsolaris: |
| symo = int64(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen) |
| symo = ld.Rnd(symo, int64(*ld.FlagRound)) |
| |
| case objabi.Hwindows: |
| symo = int64(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen) |
| symo = ld.Rnd(symo, ld.PEFILEALIGN) |
| } |
| |
| ctxt.Out.SeekSet(symo) |
| switch ctxt.HeadType { |
| default: |
| if ctxt.IsELF { |
| ctxt.Out.SeekSet(symo) |
| ld.Asmelfsym(ctxt) |
| ctxt.Out.Flush() |
| ctxt.Out.Write(ld.Elfstrdat) |
| |
| if ctxt.LinkMode == ld.LinkExternal { |
| ld.Elfemitreloc(ctxt) |
| } |
| } |
| |
| case objabi.Hplan9: |
| ld.Asmplan9sym(ctxt) |
| ctxt.Out.Flush() |
| |
| sym := ctxt.Syms.Lookup("pclntab", 0) |
| if sym != nil { |
| ld.Lcsize = int32(len(sym.P)) |
| ctxt.Out.Write(sym.P) |
| ctxt.Out.Flush() |
| } |
| |
| case objabi.Hwindows: |
| // Do nothing |
| |
| case objabi.Hdarwin: |
| if ctxt.LinkMode == ld.LinkExternal { |
| ld.Machoemitreloc(ctxt) |
| } |
| } |
| } |
| |
| ctxt.Out.SeekSet(0) |
| switch ctxt.HeadType { |
| default: |
| case objabi.Hplan9: /* plan9 */ |
| magic := int32(4*26*26 + 7) |
| |
| magic |= 0x00008000 /* fat header */ |
| ctxt.Out.Write32b(uint32(magic)) /* magic */ |
| ctxt.Out.Write32b(uint32(ld.Segtext.Filelen)) /* sizes */ |
| ctxt.Out.Write32b(uint32(ld.Segdata.Filelen)) |
| ctxt.Out.Write32b(uint32(ld.Segdata.Length - ld.Segdata.Filelen)) |
| ctxt.Out.Write32b(uint32(ld.Symsize)) /* nsyms */ |
| vl := ld.Entryvalue(ctxt) |
| ctxt.Out.Write32b(PADDR(uint32(vl))) /* va of entry */ |
| ctxt.Out.Write32b(uint32(ld.Spsize)) /* sp offsets */ |
| ctxt.Out.Write32b(uint32(ld.Lcsize)) /* line offsets */ |
| ctxt.Out.Write64b(uint64(vl)) /* va of entry */ |
| |
| case objabi.Hdarwin: |
| ld.Asmbmacho(ctxt) |
| |
| case objabi.Hlinux, |
| objabi.Hfreebsd, |
| objabi.Hnetbsd, |
| objabi.Hopenbsd, |
| objabi.Hdragonfly, |
| objabi.Hsolaris: |
| ld.Asmbelf(ctxt, symo) |
| |
| case objabi.Hwindows: |
| ld.Asmbpe(ctxt) |
| } |
| |
| ctxt.Out.Flush() |
| } |
| |
| func tlsIEtoLE(s *sym.Symbol, off, size int) { |
| // Transform the PC-relative instruction into a constant load. |
| // That is, |
| // |
| // MOVQ X(IP), REG -> MOVQ $Y, REG |
| // |
| // To determine the instruction and register, we study the op codes. |
| // Consult an AMD64 instruction encoding guide to decipher this. |
| if off < 3 { |
| log.Fatal("R_X86_64_GOTTPOFF reloc not preceded by MOVQ or ADDQ instruction") |
| } |
| op := s.P[off-3 : off] |
| reg := op[2] >> 3 |
| |
| if op[1] == 0x8b || reg == 4 { |
| // MOVQ |
| if op[0] == 0x4c { |
| op[0] = 0x49 |
| } else if size == 4 && op[0] == 0x44 { |
| op[0] = 0x41 |
| } |
| if op[1] == 0x8b { |
| op[1] = 0xc7 |
| } else { |
| op[1] = 0x81 // special case for SP |
| } |
| op[2] = 0xc0 | reg |
| } else { |
| // An alternate op is ADDQ. This is handled by GNU gold, |
| // but right now is not generated by the Go compiler: |
| // ADDQ X(IP), REG -> ADDQ $Y, REG |
| // Consider adding support for it here. |
| log.Fatalf("expected TLS IE op to be MOVQ, got %v", op) |
| } |
| } |
