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[dev.link] cmd/link: support new dodata for elf/386
Add elf/386 arch support for the new dodata() phase. Change-Id: I78341dfe70a90719d95c0044183980f348a3369f Reviewed-on: https://go-review.googlesource.com/c/go/+/229797 Run-TryBot: Than McIntosh <thanm@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
Than McIntosh
parent
3b32a44699
commit
f790533d9f
@ -157,8 +157,9 @@ func Main(arch *sys.Arch, theArch Arch) {
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}
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if *flagnewDoData {
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// New dodata() is currently only implemented for linux/amd64.
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if !(ctxt.IsElf() && ctxt.IsAMD64()) {
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// New dodata() is currently only implemented for selected targets.
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if !(ctxt.IsElf() &&
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(ctxt.IsAMD64() || ctxt.Is386())) {
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*flagnewDoData = false
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}
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}
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@ -129,161 +129,189 @@ func gentext2(ctxt *ld.Link, ldr *loader.Loader) {
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o(0xc3)
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}
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func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s *sym.Symbol, r *sym.Reloc) bool {
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targ := r.Sym
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func adddynrel2(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym, r *loader.Reloc2, rIdx int) bool {
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targ := r.Sym()
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var targType sym.SymKind
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if targ != 0 {
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targType = ldr.SymType(targ)
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}
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switch r.Type {
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switch r.Type() {
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default:
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if r.Type >= objabi.ElfRelocOffset {
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ld.Errorf(s, "unexpected relocation type %d (%s)", r.Type, sym.RelocName(target.Arch, r.Type))
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if r.Type() >= objabi.ElfRelocOffset {
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ldr.Errorf(s, "unexpected relocation type %d (%s)", r.Type(), sym.RelocName(target.Arch, r.Type()))
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return false
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}
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// Handle relocations found in ELF object files.
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case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_PC32):
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if targ.Type == sym.SDYNIMPORT {
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ld.Errorf(s, "unexpected R_386_PC32 relocation for dynamic symbol %s", targ.Name)
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if targType == sym.SDYNIMPORT {
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ldr.Errorf(s, "unexpected R_386_PC32 relocation for dynamic symbol %s", ldr.SymName(targ))
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}
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// TODO(mwhudson): the test of VisibilityHidden here probably doesn't make
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// sense and should be removed when someone has thought about it properly.
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if (targ.Type == 0 || targ.Type == sym.SXREF) && !targ.Attr.VisibilityHidden() {
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ld.Errorf(s, "unknown symbol %s in pcrel", targ.Name)
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if (targType == 0 || targType == sym.SXREF) && !ldr.AttrVisibilityHidden(targ) {
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ldr.Errorf(s, "unknown symbol %s in pcrel", ldr.SymName(targ))
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}
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r.Type = objabi.R_PCREL
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r.Add += 4
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su := ldr.MakeSymbolUpdater(s)
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su.SetRelocType(rIdx, objabi.R_PCREL)
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su.SetRelocAdd(rIdx, r.Add()+4)
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return true
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case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_PLT32):
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r.Type = objabi.R_PCREL
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r.Add += 4
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if targ.Type == sym.SDYNIMPORT {
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addpltsym(target, syms, targ)
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r.Sym = syms.PLT
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r.Add += int64(targ.Plt())
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su := ldr.MakeSymbolUpdater(s)
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su.SetRelocType(rIdx, objabi.R_PCREL)
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su.SetRelocAdd(rIdx, r.Add()+4)
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if targType == sym.SDYNIMPORT {
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addpltsym2(target, ldr, syms, targ)
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su.SetRelocSym(rIdx, syms.PLT2)
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su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymPlt(targ)))
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}
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return true
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case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOT32),
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objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOT32X):
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if targ.Type != sym.SDYNIMPORT {
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su := ldr.MakeSymbolUpdater(s)
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if targType != sym.SDYNIMPORT {
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// have symbol
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if r.Off >= 2 && s.P[r.Off-2] == 0x8b {
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// turn MOVL of GOT entry into LEAL of symbol address, relative to GOT.
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s.P[r.Off-2] = 0x8d
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sData := ldr.Data(s)
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r.Type = objabi.R_GOTOFF
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if r.Off() >= 2 && sData[r.Off()-2] == 0x8b {
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su.MakeWritable()
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// turn MOVL of GOT entry into LEAL of symbol address, relative to GOT.
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writeableData := su.Data()
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writeableData[r.Off()-2] = 0x8d
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su.SetRelocType(rIdx, objabi.R_GOTOFF)
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return true
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}
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if r.Off >= 2 && s.P[r.Off-2] == 0xff && s.P[r.Off-1] == 0xb3 {
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if r.Off() >= 2 && sData[r.Off()-2] == 0xff && sData[r.Off()-1] == 0xb3 {
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su.MakeWritable()
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// turn PUSHL of GOT entry into PUSHL of symbol itself.
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// use unnecessary SS prefix to keep instruction same length.
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s.P[r.Off-2] = 0x36
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s.P[r.Off-1] = 0x68
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r.Type = objabi.R_ADDR
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writeableData := su.Data()
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writeableData[r.Off()-2] = 0x36
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writeableData[r.Off()-1] = 0x68
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su.SetRelocType(rIdx, objabi.R_ADDR)
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return true
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}
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ld.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", targ.Name)
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ldr.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", ldr.SymName(targ))
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return false
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}
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addgotsym(target, syms, targ)
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r.Type = objabi.R_CONST // write r->add during relocsym
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r.Sym = nil
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r.Add += int64(targ.Got())
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addgotsym2(target, ldr, syms, targ)
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su.SetRelocType(rIdx, objabi.R_CONST) // write r->add during relocsym
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su.SetRelocSym(rIdx, 0)
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su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymGot(targ)))
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return true
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case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOTOFF):
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r.Type = objabi.R_GOTOFF
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su := ldr.MakeSymbolUpdater(s)
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su.SetRelocType(rIdx, objabi.R_GOTOFF)
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return true
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case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOTPC):
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r.Type = objabi.R_PCREL
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r.Sym = syms.GOT
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r.Add += 4
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su := ldr.MakeSymbolUpdater(s)
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su.SetRelocType(rIdx, objabi.R_PCREL)
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su.SetRelocSym(rIdx, syms.GOT2)
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su.SetRelocAdd(rIdx, r.Add()+4)
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return true
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case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_32):
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if targ.Type == sym.SDYNIMPORT {
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ld.Errorf(s, "unexpected R_386_32 relocation for dynamic symbol %s", targ.Name)
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if targType == sym.SDYNIMPORT {
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ldr.Errorf(s, "unexpected R_386_32 relocation for dynamic symbol %s", ldr.SymName(targ))
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}
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r.Type = objabi.R_ADDR
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su := ldr.MakeSymbolUpdater(s)
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su.SetRelocType(rIdx, objabi.R_ADDR)
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return true
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case objabi.MachoRelocOffset + ld.MACHO_GENERIC_RELOC_VANILLA*2 + 0:
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r.Type = objabi.R_ADDR
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if targ.Type == sym.SDYNIMPORT {
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ld.Errorf(s, "unexpected reloc for dynamic symbol %s", targ.Name)
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su := ldr.MakeSymbolUpdater(s)
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su.SetRelocType(rIdx, objabi.R_ADDR)
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if targType == sym.SDYNIMPORT {
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ldr.Errorf(s, "unexpected reloc for dynamic symbol %s", ldr.SymName(targ))
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}
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return true
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case objabi.MachoRelocOffset + ld.MACHO_GENERIC_RELOC_VANILLA*2 + 1:
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if targ.Type == sym.SDYNIMPORT {
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addpltsym(target, syms, targ)
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r.Sym = syms.PLT
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r.Add = int64(targ.Plt())
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r.Type = objabi.R_PCREL
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su := ldr.MakeSymbolUpdater(s)
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if targType == sym.SDYNIMPORT {
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addpltsym2(target, ldr, syms, targ)
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su.SetRelocSym(rIdx, syms.PLT2)
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su.SetRelocAdd(rIdx, int64(ldr.SymPlt(targ)))
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su.SetRelocType(rIdx, objabi.R_PCREL)
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return true
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}
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r.Type = objabi.R_PCREL
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su.SetRelocType(rIdx, objabi.R_PCREL)
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return true
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case objabi.MachoRelocOffset + ld.MACHO_FAKE_GOTPCREL:
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if targ.Type != sym.SDYNIMPORT {
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su := ldr.MakeSymbolUpdater(s)
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if targType != sym.SDYNIMPORT {
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// have symbol
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// turn MOVL of GOT entry into LEAL of symbol itself
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if r.Off < 2 || s.P[r.Off-2] != 0x8b {
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ld.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", targ.Name)
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sData := ldr.Data(s)
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if r.Off() < 2 || sData[r.Off()-2] != 0x8b {
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ldr.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", ldr.SymName(targ))
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return false
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}
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s.P[r.Off-2] = 0x8d
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r.Type = objabi.R_PCREL
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su.MakeWritable()
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writeableData := su.Data()
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writeableData[r.Off()-2] = 0x8d
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su.SetRelocType(rIdx, objabi.R_PCREL)
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return true
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}
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addgotsym(target, syms, targ)
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r.Sym = syms.GOT
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r.Add += int64(targ.Got())
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r.Type = objabi.R_PCREL
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addgotsym2(target, ldr, syms, targ)
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su.SetRelocSym(rIdx, syms.GOT2)
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su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymGot(targ)))
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su.SetRelocType(rIdx, objabi.R_PCREL)
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return true
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}
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// Handle references to ELF symbols from our own object files.
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if targ.Type != sym.SDYNIMPORT {
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if targType != sym.SDYNIMPORT {
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return true
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}
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switch r.Type {
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// Reread the reloc to incorporate any changes in type above.
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relocs := ldr.Relocs(s)
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*r = relocs.At2(rIdx)
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switch r.Type() {
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case objabi.R_CALL,
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objabi.R_PCREL:
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if target.IsExternal() {
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// External linker will do this relocation.
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return true
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}
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addpltsym(target, syms, targ)
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r.Sym = syms.PLT
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r.Add = int64(targ.Plt())
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addpltsym2(target, ldr, syms, targ)
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su := ldr.MakeSymbolUpdater(s)
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su.SetRelocSym(rIdx, syms.PLT2)
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su.SetRelocAdd(rIdx, int64(ldr.SymPlt(targ)))
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return true
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case objabi.R_ADDR:
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if s.Type != sym.SDATA {
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if ldr.SymType(s) != sym.SDATA {
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break
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}
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if target.IsElf() {
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ld.Adddynsym(target, syms, targ)
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rel := syms.Rel
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rel.AddAddrPlus(target.Arch, s, int64(r.Off))
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rel.AddUint32(target.Arch, ld.ELF32_R_INFO(uint32(targ.Dynid), uint32(elf.R_386_32)))
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r.Type = objabi.R_CONST // write r->add during relocsym
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r.Sym = nil
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ld.Adddynsym2(ldr, target, syms, targ)
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rel := ldr.MakeSymbolUpdater(syms.Rel2)
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rel.AddAddrPlus(target.Arch, s, int64(r.Off()))
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rel.AddUint32(target.Arch, ld.ELF32_R_INFO(uint32(ldr.SymDynid(targ)), uint32(elf.R_386_32)))
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su := ldr.MakeSymbolUpdater(s)
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su.SetRelocType(rIdx, objabi.R_CONST) // write r->add during relocsym
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su.SetRelocSym(rIdx, 0)
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return true
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}
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if target.IsDarwin() && s.Size == int64(target.Arch.PtrSize) && r.Off == 0 {
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if target.IsDarwin() && ldr.SymSize(s) == int64(target.Arch.PtrSize) && r.Off() == 0 {
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// Mach-O relocations are a royal pain to lay out.
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// They use a compact stateful bytecode representation
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// that is too much bother to deal with.
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@ -294,18 +322,17 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s *sym.
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// just in case the C code assigns to the variable,
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// and of course it only works for single pointers,
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// but we only need to support cgo and that's all it needs.
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ld.Adddynsym(target, syms, targ)
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ld.Adddynsym2(ldr, target, syms, targ)
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got := syms.GOT
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s.Type = got.Type
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s.Attr |= sym.AttrSubSymbol
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s.Outer = got
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s.Sub = got.Sub
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got.Sub = s
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s.Value = got.Size
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got := ldr.MakeSymbolUpdater(syms.GOT2)
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su := ldr.MakeSymbolUpdater(s)
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su.SetType(got.Type())
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got.PrependSub(s)
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su.SetValue(got.Size())
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got.AddUint32(target.Arch, 0)
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syms.LinkEditGOT.AddUint32(target.Arch, uint32(targ.Dynid))
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r.Type = objabi.ElfRelocOffset // ignore during relocsym
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leg := ldr.MakeSymbolUpdater(syms.LinkEditGOT2)
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leg.AddUint32(target.Arch, uint32(ldr.SymDynid(targ)))
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su.SetRelocType(rIdx, objabi.ElfRelocOffset) // ignore during relocsym
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return true
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}
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}
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@ -452,18 +479,18 @@ func elfsetupplt(ctxt *ld.Link, plt, got *loader.SymbolBuilder, dynamic loader.S
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}
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}
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func addpltsym(target *ld.Target, syms *ld.ArchSyms, s *sym.Symbol) {
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if s.Plt() >= 0 {
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func addpltsym2(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym) {
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if ldr.SymPlt(s) >= 0 {
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return
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}
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ld.Adddynsym(target, syms, s)
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ld.Adddynsym2(ldr, target, syms, s)
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if target.IsElf() {
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plt := syms.PLT
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got := syms.GOTPLT
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rel := syms.RelPLT
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if plt.Size == 0 {
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plt := ldr.MakeSymbolUpdater(syms.PLT2)
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got := ldr.MakeSymbolUpdater(syms.GOTPLT2)
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rel := ldr.MakeSymbolUpdater(syms.RelPLT2)
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if plt.Size() == 0 {
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panic("plt is not set up")
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}
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@ -471,65 +498,69 @@ func addpltsym(target *ld.Target, syms *ld.ArchSyms, s *sym.Symbol) {
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plt.AddUint8(0xff)
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plt.AddUint8(0x25)
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plt.AddAddrPlus(target.Arch, got, got.Size)
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plt.AddAddrPlus(target.Arch, got.Sym(), got.Size())
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// add to got: pointer to current pos in plt
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got.AddAddrPlus(target.Arch, plt, plt.Size)
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got.AddAddrPlus(target.Arch, plt.Sym(), plt.Size())
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// pushl $x
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plt.AddUint8(0x68)
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plt.AddUint32(target.Arch, uint32(rel.Size))
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plt.AddUint32(target.Arch, uint32(rel.Size()))
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// jmp .plt
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plt.AddUint8(0xe9)
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plt.AddUint32(target.Arch, uint32(-(plt.Size + 4)))
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plt.AddUint32(target.Arch, uint32(-(plt.Size() + 4)))
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// rel
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rel.AddAddrPlus(target.Arch, got, got.Size-4)
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rel.AddAddrPlus(target.Arch, got.Sym(), got.Size()-4)
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rel.AddUint32(target.Arch, ld.ELF32_R_INFO(uint32(s.Dynid), uint32(elf.R_386_JMP_SLOT)))
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sDynid := ldr.SymDynid(s)
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rel.AddUint32(target.Arch, ld.ELF32_R_INFO(uint32(sDynid), uint32(elf.R_386_JMP_SLOT)))
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s.SetPlt(int32(plt.Size - 16))
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ldr.SetPlt(s, int32(plt.Size()-16))
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} else if target.IsDarwin() {
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// Same laziness as in 6l.
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plt := syms.PLT
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plt := ldr.MakeSymbolUpdater(syms.PLT2)
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addgotsym(target, syms, s)
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addgotsym2(target, ldr, syms, s)
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syms.LinkEditPLT.AddUint32(target.Arch, uint32(s.Dynid))
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sDynid := ldr.SymDynid(s)
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lep := ldr.MakeSymbolUpdater(syms.LinkEditPLT2)
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lep.AddUint32(target.Arch, uint32(sDynid))
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// jmpq *got+size(IP)
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s.SetPlt(int32(plt.Size))
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ldr.SetPlt(s, int32(plt.Size()))
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plt.AddUint8(0xff)
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plt.AddUint8(0x25)
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plt.AddAddrPlus(target.Arch, syms.GOT, int64(s.Got()))
|
||||
plt.AddAddrPlus(target.Arch, syms.GOT2, int64(ldr.SymGot(s)))
|
||||
} else {
|
||||
ld.Errorf(s, "addpltsym: unsupported binary format")
|
||||
ldr.Errorf(s, "addpltsym: unsupported binary format")
|
||||
}
|
||||
}
|
||||
|
||||
func addgotsym(target *ld.Target, syms *ld.ArchSyms, s *sym.Symbol) {
|
||||
if s.Got() >= 0 {
|
||||
func addgotsym2(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym) {
|
||||
if ldr.SymGot(s) >= 0 {
|
||||
return
|
||||
}
|
||||
|
||||
ld.Adddynsym(target, syms, s)
|
||||
got := syms.GOT
|
||||
s.SetGot(int32(got.Size))
|
||||
ld.Adddynsym2(ldr, target, syms, s)
|
||||
got := ldr.MakeSymbolUpdater(syms.GOT2)
|
||||
ldr.SetGot(s, int32(got.Size()))
|
||||
got.AddUint32(target.Arch, 0)
|
||||
|
||||
if target.IsElf() {
|
||||
rel := syms.Rel
|
||||
rel.AddAddrPlus(target.Arch, got, int64(s.Got()))
|
||||
rel.AddUint32(target.Arch, ld.ELF32_R_INFO(uint32(s.Dynid), uint32(elf.R_386_GLOB_DAT)))
|
||||
rel := ldr.MakeSymbolUpdater(syms.Rel2)
|
||||
rel.AddAddrPlus(target.Arch, got.Sym(), int64(ldr.SymGot(s)))
|
||||
rel.AddUint32(target.Arch, ld.ELF32_R_INFO(uint32(ldr.SymDynid(s)), uint32(elf.R_386_GLOB_DAT)))
|
||||
} else if target.IsDarwin() {
|
||||
syms.LinkEditGOT.AddUint32(target.Arch, uint32(s.Dynid))
|
||||
leg := ldr.MakeSymbolUpdater(syms.LinkEditGOT2)
|
||||
leg.AddUint32(target.Arch, uint32(ldr.SymDynid(s)))
|
||||
} else {
|
||||
ld.Errorf(s, "addgotsym: unsupported binary format")
|
||||
ldr.Errorf(s, "addgotsym: unsupported binary format")
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
283
src/cmd/link/internal/x86/asm2.go
Normal file
283
src/cmd/link/internal/x86/asm2.go
Normal file
@ -0,0 +1,283 @@
|
||||
// Copyright 2020 The Go Authors. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
package x86
|
||||
|
||||
import (
|
||||
"cmd/internal/objabi"
|
||||
"cmd/link/internal/ld"
|
||||
"cmd/link/internal/loader"
|
||||
"cmd/link/internal/sym"
|
||||
"debug/elf"
|
||||
)
|
||||
|
||||
// Temporary dumping around for sym.Symbol version of helper
|
||||
// functions in asm.go, still being used for some oses.
|
||||
// FIXME: get rid of this file when dodata() is completely
|
||||
// converted.
|
||||
|
||||
func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, 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(target.Arch, r.Type))
|
||||
return false
|
||||
}
|
||||
|
||||
// Handle relocations found in ELF object files.
|
||||
case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_PC32):
|
||||
if targ.Type == sym.SDYNIMPORT {
|
||||
ld.Errorf(s, "unexpected R_386_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_386_PLT32):
|
||||
r.Type = objabi.R_PCREL
|
||||
r.Add += 4
|
||||
if targ.Type == sym.SDYNIMPORT {
|
||||
addpltsym(target, syms, targ)
|
||||
r.Sym = syms.PLT
|
||||
r.Add += int64(targ.Plt())
|
||||
}
|
||||
|
||||
return true
|
||||
|
||||
case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOT32),
|
||||
objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOT32X):
|
||||
if targ.Type != sym.SDYNIMPORT {
|
||||
// have symbol
|
||||
if r.Off >= 2 && s.P[r.Off-2] == 0x8b {
|
||||
// turn MOVL of GOT entry into LEAL of symbol address, relative to GOT.
|
||||
s.P[r.Off-2] = 0x8d
|
||||
|
||||
r.Type = objabi.R_GOTOFF
|
||||
return true
|
||||
}
|
||||
|
||||
if r.Off >= 2 && s.P[r.Off-2] == 0xff && s.P[r.Off-1] == 0xb3 {
|
||||
// turn PUSHL of GOT entry into PUSHL of symbol itself.
|
||||
// use unnecessary SS prefix to keep instruction same length.
|
||||
s.P[r.Off-2] = 0x36
|
||||
|
||||
s.P[r.Off-1] = 0x68
|
||||
r.Type = objabi.R_ADDR
|
||||
return true
|
||||
}
|
||||
|
||||
ld.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", targ.Name)
|
||||
return false
|
||||
}
|
||||
|
||||
addgotsym(target, syms, targ)
|
||||
r.Type = objabi.R_CONST // write r->add during relocsym
|
||||
r.Sym = nil
|
||||
r.Add += int64(targ.Got())
|
||||
return true
|
||||
|
||||
case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOTOFF):
|
||||
r.Type = objabi.R_GOTOFF
|
||||
return true
|
||||
|
||||
case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOTPC):
|
||||
r.Type = objabi.R_PCREL
|
||||
r.Sym = syms.GOT
|
||||
r.Add += 4
|
||||
return true
|
||||
|
||||
case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_32):
|
||||
if targ.Type == sym.SDYNIMPORT {
|
||||
ld.Errorf(s, "unexpected R_386_32 relocation for dynamic symbol %s", targ.Name)
|
||||
}
|
||||
r.Type = objabi.R_ADDR
|
||||
return true
|
||||
|
||||
case objabi.MachoRelocOffset + ld.MACHO_GENERIC_RELOC_VANILLA*2 + 0:
|
||||
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_GENERIC_RELOC_VANILLA*2 + 1:
|
||||
if targ.Type == sym.SDYNIMPORT {
|
||||
addpltsym(target, syms, targ)
|
||||
r.Sym = syms.PLT
|
||||
r.Add = int64(targ.Plt())
|
||||
r.Type = objabi.R_PCREL
|
||||
return true
|
||||
}
|
||||
|
||||
r.Type = objabi.R_PCREL
|
||||
return true
|
||||
|
||||
case objabi.MachoRelocOffset + ld.MACHO_FAKE_GOTPCREL:
|
||||
if targ.Type != sym.SDYNIMPORT {
|
||||
// have symbol
|
||||
// turn MOVL of GOT entry into LEAL of symbol itself
|
||||
if r.Off < 2 || s.P[r.Off-2] != 0x8b {
|
||||
ld.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", targ.Name)
|
||||
return false
|
||||
}
|
||||
|
||||
s.P[r.Off-2] = 0x8d
|
||||
r.Type = objabi.R_PCREL
|
||||
return true
|
||||
}
|
||||
|
||||
addgotsym(target, syms, targ)
|
||||
r.Sym = syms.GOT
|
||||
r.Add += int64(targ.Got())
|
||||
r.Type = objabi.R_PCREL
|
||||
return true
|
||||
}
|
||||
|
||||
// Handle references to ELF symbols from our own object files.
|
||||
if targ.Type != sym.SDYNIMPORT {
|
||||
return true
|
||||
}
|
||||
switch r.Type {
|
||||
case objabi.R_CALL,
|
||||
objabi.R_PCREL:
|
||||
if target.IsExternal() {
|
||||
// External linker will do this relocation.
|
||||
return true
|
||||
}
|
||||
addpltsym(target, syms, targ)
|
||||
r.Sym = syms.PLT
|
||||
r.Add = int64(targ.Plt())
|
||||
return true
|
||||
|
||||
case objabi.R_ADDR:
|
||||
if s.Type != sym.SDATA {
|
||||
break
|
||||
}
|
||||
if target.IsElf() {
|
||||
ld.Adddynsym(target, syms, targ)
|
||||
rel := syms.Rel
|
||||
rel.AddAddrPlus(target.Arch, s, int64(r.Off))
|
||||
rel.AddUint32(target.Arch, ld.ELF32_R_INFO(uint32(targ.Dynid), uint32(elf.R_386_32)))
|
||||
r.Type = objabi.R_CONST // write r->add during relocsym
|
||||
r.Sym = nil
|
||||
return true
|
||||
}
|
||||
|
||||
if target.IsDarwin() && s.Size == int64(target.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(target, syms, targ)
|
||||
|
||||
got := syms.GOT
|
||||
s.Type = got.Type
|
||||
s.Attr |= sym.AttrSubSymbol
|
||||
s.Outer = got
|
||||
s.Sub = got.Sub
|
||||
got.Sub = s
|
||||
s.Value = got.Size
|
||||
got.AddUint32(target.Arch, 0)
|
||||
syms.LinkEditGOT.AddUint32(target.Arch, uint32(targ.Dynid))
|
||||
r.Type = objabi.ElfRelocOffset // ignore during relocsym
|
||||
return true
|
||||
}
|
||||
}
|
||||
|
||||
return false
|
||||
}
|
||||
|
||||
func addpltsym(target *ld.Target, syms *ld.ArchSyms, s *sym.Symbol) {
|
||||
if s.Plt() >= 0 {
|
||||
return
|
||||
}
|
||||
|
||||
ld.Adddynsym(target, syms, s)
|
||||
|
||||
if target.IsElf() {
|
||||
plt := syms.PLT
|
||||
got := syms.GOTPLT
|
||||
rel := syms.RelPLT
|
||||
if plt.Size == 0 {
|
||||
panic("plt is not set up")
|
||||
}
|
||||
|
||||
// jmpq *got+size
|
||||
plt.AddUint8(0xff)
|
||||
|
||||
plt.AddUint8(0x25)
|
||||
plt.AddAddrPlus(target.Arch, got, got.Size)
|
||||
|
||||
// add to got: pointer to current pos in plt
|
||||
got.AddAddrPlus(target.Arch, plt, plt.Size)
|
||||
|
||||
// pushl $x
|
||||
plt.AddUint8(0x68)
|
||||
|
||||
plt.AddUint32(target.Arch, uint32(rel.Size))
|
||||
|
||||
// jmp .plt
|
||||
plt.AddUint8(0xe9)
|
||||
|
||||
plt.AddUint32(target.Arch, uint32(-(plt.Size + 4)))
|
||||
|
||||
// rel
|
||||
rel.AddAddrPlus(target.Arch, got, got.Size-4)
|
||||
|
||||
rel.AddUint32(target.Arch, ld.ELF32_R_INFO(uint32(s.Dynid), uint32(elf.R_386_JMP_SLOT)))
|
||||
|
||||
s.SetPlt(int32(plt.Size - 16))
|
||||
} else if target.IsDarwin() {
|
||||
// Same laziness as in 6l.
|
||||
|
||||
plt := syms.PLT
|
||||
|
||||
addgotsym(target, syms, s)
|
||||
|
||||
syms.LinkEditPLT.AddUint32(target.Arch, uint32(s.Dynid))
|
||||
|
||||
// jmpq *got+size(IP)
|
||||
s.SetPlt(int32(plt.Size))
|
||||
|
||||
plt.AddUint8(0xff)
|
||||
plt.AddUint8(0x25)
|
||||
plt.AddAddrPlus(target.Arch, syms.GOT, int64(s.Got()))
|
||||
} else {
|
||||
ld.Errorf(s, "addpltsym: unsupported binary format")
|
||||
}
|
||||
}
|
||||
|
||||
func addgotsym(target *ld.Target, syms *ld.ArchSyms, s *sym.Symbol) {
|
||||
if s.Got() >= 0 {
|
||||
return
|
||||
}
|
||||
|
||||
ld.Adddynsym(target, syms, s)
|
||||
got := syms.GOT
|
||||
s.SetGot(int32(got.Size))
|
||||
got.AddUint32(target.Arch, 0)
|
||||
|
||||
if target.IsElf() {
|
||||
rel := syms.Rel
|
||||
rel.AddAddrPlus(target.Arch, got, int64(s.Got()))
|
||||
rel.AddUint32(target.Arch, ld.ELF32_R_INFO(uint32(s.Dynid), uint32(elf.R_386_GLOB_DAT)))
|
||||
} else if target.IsDarwin() {
|
||||
syms.LinkEditGOT.AddUint32(target.Arch, uint32(s.Dynid))
|
||||
} else {
|
||||
ld.Errorf(s, "addgotsym: unsupported binary format")
|
||||
}
|
||||
}
|
||||
@ -47,6 +47,7 @@ func Init() (*sys.Arch, ld.Arch) {
|
||||
Dwarfreglr: dwarfRegLR,
|
||||
|
||||
Adddynrel: adddynrel,
|
||||
Adddynrel2: adddynrel2,
|
||||
Archinit: archinit,
|
||||
Archreloc: archreloc,
|
||||
Archrelocvariant: archrelocvariant,
|
||||
|
||||
Loading…
Reference in New Issue
Block a user