diff options
Diffstat (limited to 'src/cmd/link/internal/amd64/asm.go')
| -rw-r--r-- | src/cmd/link/internal/amd64/asm.go | 69 |
1 files changed, 29 insertions, 40 deletions
diff --git a/src/cmd/link/internal/amd64/asm.go b/src/cmd/link/internal/amd64/asm.go index e5a6ef51b0..360c5338ba 100644 --- a/src/cmd/link/internal/amd64/asm.go +++ b/src/cmd/link/internal/amd64/asm.go @@ -76,9 +76,9 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade targType = ldr.SymType(targ) } - switch r.Type() { + switch rt := r.Type(); rt { default: - if r.Type() >= objabi.ElfRelocOffset { + if rt >= objabi.ElfRelocOffset { ldr.Errorf(s, "unexpected relocation type %d (%s)", r.Type(), sym.RelocName(target.Arch, r.Type())) return false } @@ -167,13 +167,24 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade 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? su := ldr.MakeSymbolUpdater(s) su.SetRelocType(rIdx, objabi.R_ADDR) if targType == sym.SDYNIMPORT { ldr.Errorf(s, "unexpected reloc for dynamic symbol %s", ldr.SymName(targ)) } + if target.IsPIE() && target.IsInternal() { + // For internal linking PIE, this R_ADDR relocation cannot + // be resolved statically. We need to generate a dynamic + // relocation. Let the code below handle it. + if rt == objabi.MachoRelocOffset+ld.MACHO_X86_64_RELOC_UNSIGNED*2 { + break + } else { + // MACHO_X86_64_RELOC_SIGNED or MACHO_X86_64_RELOC_BRANCH + // Can this happen? The object is expected to be PIC. + ldr.Errorf(s, "unsupported relocation for PIE: %v", rt) + } + } return true case objabi.MachoRelocOffset + ld.MACHO_X86_64_RELOC_BRANCH*2 + 1: @@ -223,7 +234,7 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade if targType != sym.SDYNIMPORT { ldr.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", ldr.SymName(targ)) } - ld.AddGotSym(target, ldr, syms, targ, uint32(elf.R_X86_64_GLOB_DAT)) + ld.AddGotSym(target, ldr, syms, targ, 0) su := ldr.MakeSymbolUpdater(s) su.SetRelocType(rIdx, objabi.R_PCREL) su.SetRelocSym(rIdx, syms.GOT) @@ -343,7 +354,7 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade rela := ldr.MakeSymbolUpdater(syms.Rela) rela.AddAddrPlus(target.Arch, s, int64(r.Off())) if r.Siz() == 8 { - rela.AddUint64(target.Arch, ld.ELF64_R_INFO(0, uint32(elf.R_X86_64_RELATIVE))) + rela.AddUint64(target.Arch, elf.R_INFO(0, uint32(elf.R_X86_64_RELATIVE))) } else { ldr.Errorf(s, "unexpected relocation for dynamic symbol %s", ldr.SymName(targ)) } @@ -355,28 +366,15 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade return true } - if target.IsDarwin() && ldr.SymSize(s) == int64(target.Arch.PtrSize) && r.Off() == 0 { + if target.IsDarwin() { // 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(ldr, target, syms, targ) - - got := ldr.MakeSymbolUpdater(syms.GOT) - su := ldr.MakeSymbolUpdater(s) - su.SetType(got.Type()) - got.AddInteriorSym(s) - su.SetValue(got.Size()) - got.AddUint64(target.Arch, 0) - leg := ldr.MakeSymbolUpdater(syms.LinkEditGOT) - leg.AddUint32(target.Arch, uint32(ldr.SymDynid(targ))) - su.SetRelocType(rIdx, objabi.ElfRelocOffset) // ignore during relocsym + // They use a compact stateful bytecode representation. + // Here we record what are needed and encode them later. + ld.MachoAddRebase(s, int64(r.Off())) + // Not mark r done here. So we still apply it statically, + // so in the file content we'll also have the right offset + // to the relocation target. So it can be examined statically + // (e.g. go version). return true } } @@ -622,31 +620,21 @@ func addpltsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade rela.AddAddrPlus(target.Arch, got.Sym(), got.Size()-8) sDynid := ldr.SymDynid(s) - rela.AddUint64(target.Arch, ld.ELF64_R_INFO(uint32(sDynid), uint32(elf.R_X86_64_JMP_SLOT))) + rela.AddUint64(target.Arch, elf.R_INFO(uint32(sDynid), uint32(elf.R_X86_64_JMP_SLOT))) rela.AddUint64(target.Arch, 0) ldr.SetPlt(s, int32(plt.Size()-16)) } else if target.IsDarwin() { - // 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. - - ld.AddGotSym(target, ldr, syms, s, uint32(elf.R_X86_64_GLOB_DAT)) - plt := ldr.MakeSymbolUpdater(syms.PLT) + ld.AddGotSym(target, ldr, syms, s, 0) sDynid := ldr.SymDynid(s) lep := ldr.MakeSymbolUpdater(syms.LinkEditPLT) lep.AddUint32(target.Arch, uint32(sDynid)) - // jmpq *got+size(IP) + plt := ldr.MakeSymbolUpdater(syms.PLT) ldr.SetPlt(s, int32(plt.Size())) + // jmpq *got+size(IP) plt.AddUint8(0xff) plt.AddUint8(0x25) plt.AddPCRelPlus(target.Arch, syms.GOT, int64(ldr.SymGot(s))) @@ -654,6 +642,7 @@ func addpltsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade ldr.Errorf(s, "addpltsym: unsupported binary format") } } + func tlsIEtoLE(P []byte, off, size int) { // Transform the PC-relative instruction into a constant load. // That is, |