X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FMC%2FELFObjectWriter.cpp;h=45e9c3b3d3179274100374406ac4348c392c266e;hb=9baee3b3a3924bc45d007e54c71333739d135f8e;hp=35f029d2fa11ec27b58bb55f85f50d550c25388c;hpb=ad49cf586624c400302d17ecc2c2e41ea4346f1a;p=oota-llvm.git diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp index 35f029d2fa1..45e9c3b3d31 100644 --- a/lib/MC/ELFObjectWriter.cpp +++ b/lib/MC/ELFObjectWriter.cpp @@ -12,6 +12,7 @@ //===----------------------------------------------------------------------===// #include "llvm/MC/ELFObjectWriter.h" +#include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/StringMap.h" #include "llvm/ADT/Twine.h" @@ -43,21 +44,54 @@ static unsigned GetType(const MCSymbolData &SD) { return Type; } +static unsigned GetBinding(const MCSymbolData &SD) { + uint32_t Binding = (SD.getFlags() & (0xf << ELF_STB_Shift)) >> ELF_STB_Shift; + assert(Binding == ELF::STB_LOCAL || Binding == ELF::STB_GLOBAL || + Binding == ELF::STB_WEAK); + return Binding; +} + +static void SetBinding(MCSymbolData &SD, unsigned Binding) { + assert(Binding == ELF::STB_LOCAL || Binding == ELF::STB_GLOBAL || + Binding == ELF::STB_WEAK); + uint32_t OtherFlags = SD.getFlags() & ~(0xf << ELF_STB_Shift); + SD.setFlags(OtherFlags | (Binding << ELF_STB_Shift)); +} + +static unsigned GetVisibility(MCSymbolData &SD) { + unsigned Visibility = + (SD.getFlags() & (0xf << ELF_STV_Shift)) >> ELF_STV_Shift; + assert(Visibility == ELF::STV_DEFAULT || Visibility == ELF::STV_INTERNAL || + Visibility == ELF::STV_HIDDEN || Visibility == ELF::STV_PROTECTED); + return Visibility; +} + +static bool isFixupKindX86PCRel(unsigned Kind) { + switch (Kind) { + default: + return false; + case X86::reloc_pcrel_1byte: + case X86::reloc_pcrel_4byte: + case X86::reloc_riprel_4byte: + case X86::reloc_riprel_4byte_movq_load: + return true; + } +} + +static bool RelocNeedsGOT(unsigned Type) { + switch (Type) { + default: + return false; + case ELF::R_X86_64_GOT32: + case ELF::R_X86_64_PLT32: + case ELF::R_X86_64_GOTPCREL: + return true; + } +} + namespace { class ELFObjectWriterImpl { - static bool isFixupKindX86PCRel(unsigned Kind) { - switch (Kind) { - default: - return false; - case X86::reloc_pcrel_1byte: - case X86::reloc_pcrel_4byte: - case X86::reloc_riprel_4byte: - case X86::reloc_riprel_4byte_movq_load: - return true; - } - } - /*static bool isFixupKindX86RIPRel(unsigned Kind) { return Kind == X86::reloc_riprel_4byte || Kind == X86::reloc_riprel_4byte_movq_load; @@ -88,7 +122,9 @@ namespace { struct ELFRelocationEntry { // Make these big enough for both 32-bit and 64-bit uint64_t r_offset; - uint64_t r_info; + int Index; + unsigned Type; + const MCSymbol *Symbol; uint64_t r_addend; // Support lexicographic sorting. @@ -97,6 +133,8 @@ namespace { } }; + SmallPtrSet UsedInReloc; + llvm::DenseMap > Relocations; DenseMap SectionStringTableIndex; @@ -112,6 +150,10 @@ namespace { /// @} + int NumRegularSections; + + bool NeedsGOT; + ELFObjectWriter *Writer; raw_ostream &OS; @@ -132,7 +174,7 @@ namespace { public: ELFObjectWriterImpl(ELFObjectWriter *_Writer, bool _Is64Bit, bool _HasRelAddend, Triple::OSType _OSType) - : Writer(_Writer), OS(Writer->getStream()), + : NeedsGOT(false), Writer(_Writer), OS(Writer->getStream()), Is64Bit(_Is64Bit), HasRelocationAddend(_HasRelAddend), OSType(_OSType) { } @@ -248,8 +290,6 @@ namespace { void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout); void ExecutePostLayoutBinding(MCAssembler &Asm) { - // Compute symbol table information. - ComputeSymbolTable(Asm); } void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags, @@ -260,7 +300,12 @@ namespace { void WriteRelocationsFragment(const MCAssembler &Asm, MCDataFragment *F, const MCSectionData *SD); - void WriteObject(const MCAssembler &Asm, const MCAsmLayout &Layout); + bool IsFixupFullyResolved(const MCAssembler &Asm, + const MCValue Target, + bool IsPCRel, + const MCFragment *DF) const; + + void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout); }; } @@ -374,22 +419,51 @@ void ELFObjectWriterImpl::WriteSymbolEntry(MCDataFragment *F, uint64_t name, } } +static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout) { + if (Data.isCommon() && Data.isExternal()) + return Data.getCommonAlignment(); + + const MCSymbol &Symbol = Data.getSymbol(); + if (!Symbol.isInSection()) + return 0; + + if (!Data.isCommon() && !(Data.getFlags() & ELF_STB_Weak)) + if (MCFragment *FF = Data.getFragment()) + return Layout.getSymbolAddress(&Data) - + Layout.getSectionAddress(FF->getParent()); + + return 0; +} + +static const MCSymbol &AliasedSymbol(const MCSymbol &Symbol) { + const MCSymbol *S = &Symbol; + while (S->isVariable()) { + const MCExpr *Value = S->getVariableValue(); + assert (Value->getKind() == MCExpr::SymbolRef && "Unimplemented"); + const MCSymbolRefExpr *Ref = static_cast(Value); + S = &Ref->getSymbol(); + } + return *S; +} + void ELFObjectWriterImpl::WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD, const MCAsmLayout &Layout) { - MCSymbolData &Data = *MSD.SymbolData; - uint8_t Info = (Data.getFlags() & 0xff); - uint8_t Other = ((Data.getFlags() & 0xf00) >> ELF_STV_Shift); - uint64_t Value = 0; + MCSymbolData &OrigData = *MSD.SymbolData; + MCSymbolData &Data = + Layout.getAssembler().getSymbolData(AliasedSymbol(OrigData.getSymbol())); + + uint8_t Binding = GetBinding(OrigData); + uint8_t Visibility = GetVisibility(OrigData); + uint8_t Type = GetType(Data); + + uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift); + uint8_t Other = Visibility; + + uint64_t Value = SymbolValue(Data, Layout); uint64_t Size = 0; const MCExpr *ESize; - if (Data.isCommon() && Data.isExternal()) - Value = Data.getCommonAlignment(); - - if (!Data.isCommon() && !(Data.getFlags() & ELF_STB_Weak)) - if (MCFragment *FF = Data.getFragment()) - Value = Layout.getSymbolAddress(&Data) - - Layout.getSectionAddress(FF->getParent()); + assert(!(Data.isCommon() && !Data.isExternal())); ESize = Data.getSize(); if (Data.getSize()) { @@ -398,12 +472,9 @@ void ELFObjectWriterImpl::WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD, const MCBinaryExpr *BE = static_cast(ESize); if (BE->EvaluateAsRelocatable(Res, &Layout)) { - MCSymbolData &A = - Layout.getAssembler().getSymbolData(Res.getSymA()->getSymbol()); - MCSymbolData &B = - Layout.getAssembler().getSymbolData(Res.getSymB()->getSymbol()); - - Size = Layout.getSymbolAddress(&A) - Layout.getSymbolAddress(&B); + assert(!Res.getSymA() || !Res.getSymA()->getSymbol().isDefined()); + assert(!Res.getSymB() || !Res.getSymB()->getSymbol().isDefined()); + Size = Res.getConstant(); } } else if (ESize->getKind() == MCExpr::Constant) { Size = static_cast(ESize)->getValue(); @@ -455,23 +526,52 @@ void ELFObjectWriterImpl::WriteSymbolTable(MCDataFragment *F, for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) { ELFSymbolData &MSD = ExternalSymbolData[i]; MCSymbolData &Data = *MSD.SymbolData; - assert((Data.getFlags() & ELF_STB_Global) && - "External symbol requires STB_GLOBAL flag"); + assert(((Data.getFlags() & ELF_STB_Global) || + (Data.getFlags() & ELF_STB_Weak)) && + "External symbol requires STB_GLOBAL or STB_WEAK flag"); WriteSymbol(F, MSD, Layout); - if ((Data.getFlags() & (0xf << ELF_STB_Shift)) == ELF_STB_Local) + if (GetBinding(Data) == ELF::STB_LOCAL) LastLocalSymbolIndex++; } for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) { ELFSymbolData &MSD = UndefinedSymbolData[i]; MCSymbolData &Data = *MSD.SymbolData; - Data.setFlags(Data.getFlags() | ELF_STB_Global); WriteSymbol(F, MSD, Layout); - if ((Data.getFlags() & (0xf << ELF_STB_Shift)) == ELF_STB_Local) + if (GetBinding(Data) == ELF::STB_LOCAL) LastLocalSymbolIndex++; } } +static bool ShouldRelocOnSymbol(const MCSymbolData &SD, + const MCValue &Target, + const MCFragment &F) { + const MCSymbol &Symbol = SD.getSymbol(); + if (Symbol.isUndefined()) + return true; + + const MCSectionELF &Section = + static_cast(Symbol.getSection()); + + if (SD.isExternal()) + return true; + + MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind(); + const MCSectionELF &Sec2 = + static_cast(F.getParent()->getSection()); + + if (&Sec2 != &Section && + (Kind == MCSymbolRefExpr::VK_PLT || + Kind == MCSymbolRefExpr::VK_GOTPCREL || + Kind == MCSymbolRefExpr::VK_GOTOFF)) + return true; + + if (Section.getFlags() & MCSectionELF::SHF_MERGE) + return Target.getConstant() != 0; + + return false; +} + // FIXME: this is currently X86/X86_64 only void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout, @@ -480,71 +580,100 @@ void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm, MCValue Target, uint64_t &FixedValue) { int64_t Addend = 0; - unsigned Index = 0; + int Index = 0; int64_t Value = Target.getConstant(); + const MCSymbol *Symbol = 0; bool IsPCRel = isFixupKindX86PCRel(Fixup.getKind()); if (!Target.isAbsolute()) { - const MCSymbol *Symbol = &Target.getSymA()->getSymbol(); + Symbol = &AliasedSymbol(Target.getSymA()->getSymbol()); MCSymbolData &SD = Asm.getSymbolData(*Symbol); - const MCSymbolData *Base = Asm.getAtom(Layout, &SD); MCFragment *F = SD.getFragment(); - // Avoid relocations for cases like jumps and calls in the same file. + if (const MCSymbolRefExpr *RefB = Target.getSymB()) { + const MCSymbol &SymbolB = RefB->getSymbol(); + MCSymbolData &SDB = Asm.getSymbolData(SymbolB); + IsPCRel = true; + MCSectionData *Sec = Fragment->getParent(); + + // Offset of the symbol in the section + int64_t a = Layout.getSymbolAddress(&SDB) - Layout.getSectionAddress(Sec); + + // Ofeset of the relocation in the section + int64_t b = Layout.getFragmentOffset(Fragment) + Fixup.getOffset(); + Value += b - a; + } + + // Check that this case has already been fully resolved before we get + // here. if (Symbol->isDefined() && !SD.isExternal() && IsPCRel && &Fragment->getParent()->getSection() == &Symbol->getSection()) { - uint64_t FixupAddr = Layout.getFragmentAddress(Fragment) + Fixup.getOffset(); - FixedValue = Layout.getSymbolAddress(&SD) + Target.getConstant() - FixupAddr; + llvm_unreachable("We don't need a relocation in this case."); return; } - if (Base) { - if (F && (!Symbol->isInSection() || SD.isCommon()) && !SD.isExternal()) { - Index = F->getParent()->getOrdinal() + LocalSymbolData.size() + 1; - Value += Layout.getSymbolAddress(&SD); - } else - Index = getSymbolIndexInSymbolTable(Asm, Symbol); - if (Base != &SD) - Value += Layout.getSymbolAddress(&SD) - Layout.getSymbolAddress(Base); - Addend = Value; - // Compensate for the addend on i386. - if (Is64Bit) - Value = 0; + bool RelocOnSymbol = ShouldRelocOnSymbol(SD, Target, *Fragment); + if (!RelocOnSymbol) { + Index = F->getParent()->getOrdinal(); + + MCSectionData *FSD = F->getParent(); + // Offset of the symbol in the section + Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD); } else { - if (F) { - // Index of the section in .symtab against this symbol - // is being relocated + 2 (empty section + abs. symbols). - Index = F->getParent()->getOrdinal() + LocalSymbolData.size() + 1; - - MCSectionData *FSD = F->getParent(); - // Offset of the symbol in the section - Addend = Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD); - } else { - FixedValue = Value; - return; - } + UsedInReloc.insert(Symbol); + Index = -1; } + Addend = Value; + // Compensate for the addend on i386. + if (Is64Bit) + Value = 0; } FixedValue = Value; // determine the type of the relocation + + MCSymbolRefExpr::VariantKind Modifier = Target.getSymA()->getKind(); unsigned Type; if (Is64Bit) { if (IsPCRel) { - Type = ELF::R_X86_64_PC32; + switch (Modifier) { + default: + llvm_unreachable("Unimplemented"); + case MCSymbolRefExpr::VK_None: + Type = ELF::R_X86_64_PC32; + break; + case MCSymbolRefExpr::VK_PLT: + Type = ELF::R_X86_64_PLT32; + break; + case llvm::MCSymbolRefExpr::VK_GOTPCREL: + Type = ELF::R_X86_64_GOTPCREL; + break; + } } else { switch ((unsigned)Fixup.getKind()) { default: llvm_unreachable("invalid fixup kind!"); case FK_Data_8: Type = ELF::R_X86_64_64; break; + case X86::reloc_signed_4byte: case X86::reloc_pcrel_4byte: - case FK_Data_4: - // check that the offset fits within a signed long - if (isInt<32>(Target.getConstant())) + assert(isInt<32>(Target.getConstant())); + switch (Modifier) { + default: + llvm_unreachable("Unimplemented"); + case MCSymbolRefExpr::VK_None: Type = ELF::R_X86_64_32S; - else - Type = ELF::R_X86_64_32; + break; + case MCSymbolRefExpr::VK_GOT: + Type = ELF::R_X86_64_GOT32; + break; + case MCSymbolRefExpr::VK_GOTPCREL: + Type = ELF::R_X86_64_GOTPCREL; + break; + } + break; + case FK_Data_4: + Type = ELF::R_X86_64_32; break; case FK_Data_2: Type = ELF::R_X86_64_16; break; case X86::reloc_pcrel_1byte: @@ -553,11 +682,31 @@ void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm, } } else { if (IsPCRel) { - Type = ELF::R_386_PC32; + switch (Modifier) { + default: + Type = ELF::R_386_PC32; + //llvm_unreachable("Unimplemented"); + break; + case MCSymbolRefExpr::VK_PLT: + Type = ELF::R_386_PLT32; + break; + } } else { switch ((unsigned)Fixup.getKind()) { default: llvm_unreachable("invalid fixup kind!"); + + // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode + // instead? + case X86::reloc_signed_4byte: case X86::reloc_pcrel_4byte: + switch (Modifier) { + default: + llvm_unreachable("Unimplemented"); + case MCSymbolRefExpr::VK_GOTOFF: + Type = ELF::R_386_GOTOFF; + break; + } + break; case FK_Data_4: Type = ELF::R_386_32; break; case FK_Data_2: Type = ELF::R_386_16; break; case X86::reloc_pcrel_1byte: @@ -566,17 +715,14 @@ void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm, } } + if (RelocNeedsGOT(Type)) + NeedsGOT = true; + ELFRelocationEntry ERE; - if (Is64Bit) { - struct ELF::Elf64_Rela ERE64; - ERE64.setSymbolAndType(Index, Type); - ERE.r_info = ERE64.r_info; - } else { - struct ELF::Elf32_Rela ERE32; - ERE32.setSymbolAndType(Index, Type); - ERE.r_info = ERE32.r_info; - } + ERE.Index = Index; + ERE.Type = Type; + ERE.Symbol = Symbol; ERE.r_offset = Layout.getFragmentOffset(Fragment) + Fixup.getOffset(); @@ -598,12 +744,44 @@ ELFObjectWriterImpl::getSymbolIndexInSymbolTable(const MCAssembler &Asm, return SD.getIndex() + /* empty symbol */ 1; // External or undefined symbol. - return SD.getIndex() + Asm.size() + /* empty symbol */ 1; + return SD.getIndex() + NumRegularSections + /* empty symbol */ 1; +} + +static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data, + bool Used) { + const MCSymbol &Symbol = Data.getSymbol(); + if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined()) + return false; + + if (!Used && Symbol.isTemporary()) + return false; + + return true; +} + +static bool isLocal(const MCSymbolData &Data) { + if (Data.isExternal()) + return false; + + const MCSymbol &Symbol = Data.getSymbol(); + if (Symbol.isUndefined() && !Symbol.isVariable()) + return false; + + return true; } void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) { + // FIXME: Is this the correct place to do this? + if (NeedsGOT) { + llvm::StringRef Name = "_GLOBAL_OFFSET_TABLE_"; + MCSymbol *Sym = Asm.getContext().GetOrCreateSymbol(Name); + MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym); + Data.setExternal(true); + } + // Build section lookup table. - DenseMap SectionIndexMap; + NumRegularSections = Asm.size(); + DenseMap SectionIndexMap; unsigned Index = 1; for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it, ++Index) @@ -613,77 +791,61 @@ void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) { StringMap StringIndexMap; StringTable += '\x00'; - // Add the data for local symbols. + // Add the data for the symbols. for (MCAssembler::symbol_iterator it = Asm.symbol_begin(), ie = Asm.symbol_end(); it != ie; ++it) { const MCSymbol &Symbol = it->getSymbol(); - // Ignore non-linker visible symbols. - if (!Asm.isSymbolLinkerVisible(Symbol)) - continue; - - if (it->isExternal() || Symbol.isUndefined()) + if (!isInSymtab(Asm, *it, UsedInReloc.count(&Symbol))) continue; - uint64_t &Entry = StringIndexMap[Symbol.getName()]; - if (!Entry) { - Entry = StringTable.size(); - StringTable += Symbol.getName(); - StringTable += '\x00'; - } - ELFSymbolData MSD; MSD.SymbolData = it; - MSD.StringIndex = Entry; + bool Local = isLocal(*it); - if (Symbol.isAbsolute()) { + bool Add = false; + if (it->isCommon()) { + assert(!Local); + MSD.SectionIndex = ELF::SHN_COMMON; + Add = true; + } else if (Symbol.isAbsolute()) { MSD.SectionIndex = ELF::SHN_ABS; - LocalSymbolData.push_back(MSD); + Add = true; + } else if (Symbol.isVariable()) { + const MCSymbol &RefSymbol = AliasedSymbol(Symbol); + if (RefSymbol.isDefined()) { + MSD.SectionIndex = SectionIndexMap.lookup(&RefSymbol.getSection()); + assert(MSD.SectionIndex && "Invalid section index!"); + Add = true; + } + } else if (Symbol.isUndefined()) { + assert(!Local); + MSD.SectionIndex = ELF::SHN_UNDEF; + // FIXME: Undefined symbols are global, but this is the first place we + // are able to set it. + if (GetBinding(*it) == ELF::STB_LOCAL) + SetBinding(*it, ELF::STB_GLOBAL); + Add = true; } else { MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection()); assert(MSD.SectionIndex && "Invalid section index!"); - LocalSymbolData.push_back(MSD); - } - } - - // Now add non-local symbols. - for (MCAssembler::symbol_iterator it = Asm.symbol_begin(), - ie = Asm.symbol_end(); it != ie; ++it) { - const MCSymbol &Symbol = it->getSymbol(); - - // Ignore non-linker visible symbols. - if (!Asm.isSymbolLinkerVisible(Symbol)) - continue; - - if (!it->isExternal() && !Symbol.isUndefined()) - continue; - - uint64_t &Entry = StringIndexMap[Symbol.getName()]; - if (!Entry) { - Entry = StringTable.size(); - StringTable += Symbol.getName(); - StringTable += '\x00'; + Add = true; } - ELFSymbolData MSD; - MSD.SymbolData = it; - MSD.StringIndex = Entry; - - if (Symbol.isUndefined()) { - MSD.SectionIndex = ELF::SHN_UNDEF; - // XXX: for some reason we dont Emit* this - it->setFlags(it->getFlags() | ELF_STB_Global); - UndefinedSymbolData.push_back(MSD); - } else if (Symbol.isAbsolute()) { - MSD.SectionIndex = ELF::SHN_ABS; - ExternalSymbolData.push_back(MSD); - } else if (it->isCommon()) { - MSD.SectionIndex = ELF::SHN_COMMON; - ExternalSymbolData.push_back(MSD); - } else { - MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection()); - assert(MSD.SectionIndex && "Invalid section index!"); - ExternalSymbolData.push_back(MSD); + if (Add) { + uint64_t &Entry = StringIndexMap[Symbol.getName()]; + if (!Entry) { + Entry = StringTable.size(); + StringTable += Symbol.getName(); + StringTable += '\x00'; + } + MSD.StringIndex = Entry; + if (MSD.SectionIndex == ELF::SHN_UNDEF) + UndefinedSymbolData.push_back(MSD); + else if (Local) + LocalSymbolData.push_back(MSD); + else + ExternalSymbolData.push_back(MSD); } } @@ -733,7 +895,7 @@ void ELFObjectWriterImpl::WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout, WriteRelocationsFragment(Asm, F, &SD); - Asm.AddSectionToTheEnd(RelaSD, Layout); + Asm.AddSectionToTheEnd(*Writer, RelaSD, Layout); } } @@ -765,13 +927,19 @@ void ELFObjectWriterImpl::WriteRelocationsFragment(const MCAssembler &Asm, for (unsigned i = 0, e = Relocs.size(); i != e; ++i) { ELFRelocationEntry entry = Relocs[e - i - 1]; + if (entry.Index < 0) + entry.Index = getSymbolIndexInSymbolTable(Asm, entry.Symbol); + else + entry.Index += LocalSymbolData.size() + 1; if (Is64Bit) { char buf[8]; String64(buf, entry.r_offset); F->getContents() += StringRef(buf, 8); - String64(buf, entry.r_info); + struct ELF::Elf64_Rela ERE64; + ERE64.setSymbolAndType(entry.Index, entry.Type); + String64(buf, ERE64.r_info); F->getContents() += StringRef(buf, 8); if (HasRelocationAddend) { @@ -784,7 +952,9 @@ void ELFObjectWriterImpl::WriteRelocationsFragment(const MCAssembler &Asm, String32(buf, entry.r_offset); F->getContents() += StringRef(buf, 4); - String32(buf, entry.r_info); + struct ELF::Elf32_Rela ERE32; + ERE32.setSymbolAndType(entry.Index, entry.Type); + String32(buf, ERE32.r_info); F->getContents() += StringRef(buf, 4); if (HasRelocationAddend) { @@ -800,14 +970,12 @@ void ELFObjectWriterImpl::CreateMetadataSections(MCAssembler &Asm, MCContext &Ctx = Asm.getContext(); MCDataFragment *F; - WriteRelocations(Asm, Layout); - const MCSection *SymtabSection; unsigned EntrySize = Is64Bit ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32; unsigned NumRegularSections = Asm.size(); - // We construct .shstrtab, .symtab and .strtab is this order to match gnu as. + // We construct .shstrtab, .symtab and .strtab in this order to match gnu as. const MCSection *ShstrtabSection; ShstrtabSection = Ctx.getELFSection(".shstrtab", ELF::SHT_STRTAB, 0, SectionKind::getReadOnly(), false); @@ -828,15 +996,16 @@ void ELFObjectWriterImpl::CreateMetadataSections(MCAssembler &Asm, StrtabSD.setAlignment(1); StringTableIndex = Asm.size(); + WriteRelocations(Asm, Layout); // Symbol table F = new MCDataFragment(&SymtabSD); WriteSymbolTable(F, Asm, Layout, NumRegularSections); - Asm.AddSectionToTheEnd(SymtabSD, Layout); + Asm.AddSectionToTheEnd(*Writer, SymtabSD, Layout); F = new MCDataFragment(&StrtabSD); F->getContents().append(StringTable.begin(), StringTable.end()); - Asm.AddSectionToTheEnd(StrtabSD, Layout); + Asm.AddSectionToTheEnd(*Writer, StrtabSD, Layout); F = new MCDataFragment(&ShstrtabSD); @@ -851,6 +1020,7 @@ void ELFObjectWriterImpl::CreateMetadataSections(MCAssembler &Asm, ie = Asm.end(); it != ie; ++it) { const MCSectionELF &Section = static_cast(it->getSection()); + // FIXME: We could merge suffixes like in .text and .rela.text. // Remember the index into the string table so we can write it // into the sh_name field of the section header table. @@ -861,11 +1031,48 @@ void ELFObjectWriterImpl::CreateMetadataSections(MCAssembler &Asm, F->getContents() += '\x00'; } - Asm.AddSectionToTheEnd(ShstrtabSD, Layout); + Asm.AddSectionToTheEnd(*Writer, ShstrtabSD, Layout); +} + +bool ELFObjectWriterImpl::IsFixupFullyResolved(const MCAssembler &Asm, + const MCValue Target, + bool IsPCRel, + const MCFragment *DF) const { + // If this is a PCrel relocation, find the section this fixup value is + // relative to. + const MCSection *BaseSection = 0; + if (IsPCRel) { + BaseSection = &DF->getParent()->getSection(); + assert(BaseSection); + } + + const MCSection *SectionA = 0; + const MCSymbol *SymbolA = 0; + if (const MCSymbolRefExpr *A = Target.getSymA()) { + SymbolA = &A->getSymbol(); + SectionA = &SymbolA->getSection(); + } + + const MCSection *SectionB = 0; + if (const MCSymbolRefExpr *B = Target.getSymB()) { + SectionB = &B->getSymbol().getSection(); + } + + if (!BaseSection) + return SectionA == SectionB; + + const MCSymbolData &DataA = Asm.getSymbolData(*SymbolA); + if (DataA.isExternal()) + return false; + + return !SectionB && BaseSection == SectionA; } -void ELFObjectWriterImpl::WriteObject(const MCAssembler &Asm, +void ELFObjectWriterImpl::WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout) { + // Compute symbol table information. + ComputeSymbolTable(Asm); + CreateMetadataSections(const_cast(Asm), const_cast(Layout)); @@ -897,7 +1104,7 @@ void ELFObjectWriterImpl::WriteObject(const MCAssembler &Asm, // ... then all of the sections ... DenseMap SectionOffsetMap; - DenseMap SectionIndexMap; + DenseMap SectionIndexMap; unsigned Index = 1; for (MCAssembler::const_iterator it = Asm.begin(), @@ -1022,7 +1229,15 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm, Target, FixedValue); } -void ELFObjectWriter::WriteObject(const MCAssembler &Asm, +bool ELFObjectWriter::IsFixupFullyResolved(const MCAssembler &Asm, + const MCValue Target, + bool IsPCRel, + const MCFragment *DF) const { + return ((ELFObjectWriterImpl*) Impl)->IsFixupFullyResolved(Asm, Target, + IsPCRel, DF); +} + +void ELFObjectWriter::WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout) { ((ELFObjectWriterImpl*) Impl)->WriteObject(Asm, Layout); }