diff options
Diffstat (limited to 'lib/MC/ELFObjectWriter.cpp')
| -rw-r--r-- | lib/MC/ELFObjectWriter.cpp | 784 |
1 files changed, 282 insertions, 502 deletions
diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp index ea1629d..23c6d4c 100644 --- a/lib/MC/ELFObjectWriter.cpp +++ b/lib/MC/ELFObjectWriter.cpp @@ -11,20 +11,14 @@ // //===----------------------------------------------------------------------===// -#include "llvm/ADT/OwningPtr.h" -#include "llvm/ADT/SmallPtrSet.h" +#include "ELFObjectWriter.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/StringMap.h" #include "llvm/ADT/Twine.h" -#include "llvm/MC/MCAssembler.h" #include "llvm/MC/MCAsmLayout.h" #include "llvm/MC/MCContext.h" -#include "llvm/MC/MCELFSymbolFlags.h" #include "llvm/MC/MCExpr.h" -#include "llvm/MC/MCELFObjectWriter.h" -#include "llvm/MC/MCObjectWriter.h" #include "llvm/MC/MCSectionELF.h" -#include "llvm/MC/MCSymbol.h" #include "llvm/MC/MCValue.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" @@ -38,39 +32,14 @@ #include <vector> using namespace llvm; -static unsigned GetType(const MCSymbolData &SD) { - uint32_t Type = (SD.getFlags() & (0xf << ELF_STT_Shift)) >> ELF_STT_Shift; - assert(Type == ELF::STT_NOTYPE || Type == ELF::STT_OBJECT || - Type == ELF::STT_FUNC || Type == ELF::STT_SECTION || - Type == ELF::STT_FILE || Type == ELF::STT_COMMON || - Type == ELF::STT_TLS); - 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)); -} +bool ELFObjectWriter::isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind) { + const MCFixupKindInfo &FKI = + Asm.getBackend().getFixupKindInfo((MCFixupKind) Kind); -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; + return FKI.Flags & MCFixupKindInfo::FKF_IsPCRel; } - -static bool RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) { +bool ELFObjectWriter::RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) { switch (Variant) { default: return false; @@ -90,345 +59,6 @@ static bool RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) { } } -static bool isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind) { - const MCFixupKindInfo &FKI = - Asm.getBackend().getFixupKindInfo((MCFixupKind) Kind); - - return FKI.Flags & MCFixupKindInfo::FKF_IsPCRel; -} - -namespace { - class ELFObjectWriter : public MCObjectWriter { - protected: - /*static bool isFixupKindX86RIPRel(unsigned Kind) { - return Kind == X86::reloc_riprel_4byte || - Kind == X86::reloc_riprel_4byte_movq_load; - }*/ - - - /// ELFSymbolData - Helper struct for containing some precomputed information - /// on symbols. - struct ELFSymbolData { - MCSymbolData *SymbolData; - uint64_t StringIndex; - uint32_t SectionIndex; - - // Support lexicographic sorting. - bool operator<(const ELFSymbolData &RHS) const { - if (GetType(*SymbolData) == ELF::STT_FILE) - return true; - if (GetType(*RHS.SymbolData) == ELF::STT_FILE) - return false; - return SymbolData->getSymbol().getName() < - RHS.SymbolData->getSymbol().getName(); - } - }; - - /// @name Relocation Data - /// @{ - - struct ELFRelocationEntry { - // Make these big enough for both 32-bit and 64-bit - uint64_t r_offset; - int Index; - unsigned Type; - const MCSymbol *Symbol; - uint64_t r_addend; - - ELFRelocationEntry() - : r_offset(0), Index(0), Type(0), Symbol(0), r_addend(0) {} - - ELFRelocationEntry(uint64_t RelocOffset, int Idx, - unsigned RelType, const MCSymbol *Sym, - uint64_t Addend) - : r_offset(RelocOffset), Index(Idx), Type(RelType), - Symbol(Sym), r_addend(Addend) {} - - // Support lexicographic sorting. - bool operator<(const ELFRelocationEntry &RE) const { - return RE.r_offset < r_offset; - } - }; - - /// The target specific ELF writer instance. - llvm::OwningPtr<MCELFObjectTargetWriter> TargetObjectWriter; - - SmallPtrSet<const MCSymbol *, 16> UsedInReloc; - SmallPtrSet<const MCSymbol *, 16> WeakrefUsedInReloc; - DenseMap<const MCSymbol *, const MCSymbol *> Renames; - - llvm::DenseMap<const MCSectionData*, - std::vector<ELFRelocationEntry> > Relocations; - DenseMap<const MCSection*, uint64_t> SectionStringTableIndex; - - /// @} - /// @name Symbol Table Data - /// @{ - - SmallString<256> StringTable; - std::vector<ELFSymbolData> LocalSymbolData; - std::vector<ELFSymbolData> ExternalSymbolData; - std::vector<ELFSymbolData> UndefinedSymbolData; - - /// @} - - bool NeedsGOT; - - bool NeedsSymtabShndx; - - // This holds the symbol table index of the last local symbol. - unsigned LastLocalSymbolIndex; - // This holds the .strtab section index. - unsigned StringTableIndex; - // This holds the .symtab section index. - unsigned SymbolTableIndex; - - unsigned ShstrtabIndex; - - - const MCSymbol *SymbolToReloc(const MCAssembler &Asm, - const MCValue &Target, - const MCFragment &F) const; - - // For arch-specific emission of explicit reloc symbol - virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm, - const MCValue &Target, - const MCFragment &F, - bool IsBSS) const { - return NULL; - } - - bool is64Bit() const { return TargetObjectWriter->is64Bit(); } - bool hasRelocationAddend() const { - return TargetObjectWriter->hasRelocationAddend(); - } - - public: - ELFObjectWriter(MCELFObjectTargetWriter *MOTW, - raw_ostream &_OS, bool IsLittleEndian) - : MCObjectWriter(_OS, IsLittleEndian), - TargetObjectWriter(MOTW), - NeedsGOT(false), NeedsSymtabShndx(false){ - } - - virtual ~ELFObjectWriter(); - - void WriteWord(uint64_t W) { - if (is64Bit()) - Write64(W); - else - Write32(W); - } - - void StringLE16(char *buf, uint16_t Value) { - buf[0] = char(Value >> 0); - buf[1] = char(Value >> 8); - } - - void StringLE32(char *buf, uint32_t Value) { - StringLE16(buf, uint16_t(Value >> 0)); - StringLE16(buf + 2, uint16_t(Value >> 16)); - } - - void StringLE64(char *buf, uint64_t Value) { - StringLE32(buf, uint32_t(Value >> 0)); - StringLE32(buf + 4, uint32_t(Value >> 32)); - } - - void StringBE16(char *buf ,uint16_t Value) { - buf[0] = char(Value >> 8); - buf[1] = char(Value >> 0); - } - - void StringBE32(char *buf, uint32_t Value) { - StringBE16(buf, uint16_t(Value >> 16)); - StringBE16(buf + 2, uint16_t(Value >> 0)); - } - - void StringBE64(char *buf, uint64_t Value) { - StringBE32(buf, uint32_t(Value >> 32)); - StringBE32(buf + 4, uint32_t(Value >> 0)); - } - - void String8(MCDataFragment &F, uint8_t Value) { - char buf[1]; - buf[0] = Value; - F.getContents() += StringRef(buf, 1); - } - - void String16(MCDataFragment &F, uint16_t Value) { - char buf[2]; - if (isLittleEndian()) - StringLE16(buf, Value); - else - StringBE16(buf, Value); - F.getContents() += StringRef(buf, 2); - } - - void String32(MCDataFragment &F, uint32_t Value) { - char buf[4]; - if (isLittleEndian()) - StringLE32(buf, Value); - else - StringBE32(buf, Value); - F.getContents() += StringRef(buf, 4); - } - - void String64(MCDataFragment &F, uint64_t Value) { - char buf[8]; - if (isLittleEndian()) - StringLE64(buf, Value); - else - StringBE64(buf, Value); - F.getContents() += StringRef(buf, 8); - } - - virtual void WriteHeader(uint64_t SectionDataSize, unsigned NumberOfSections); - - /// Default e_flags = 0 - virtual void WriteEFlags() { Write32(0); } - - virtual void WriteSymbolEntry(MCDataFragment *SymtabF, MCDataFragment *ShndxF, - uint64_t name, uint8_t info, - uint64_t value, uint64_t size, - uint8_t other, uint32_t shndx, - bool Reserved); - - virtual void WriteSymbol(MCDataFragment *SymtabF, MCDataFragment *ShndxF, - ELFSymbolData &MSD, - const MCAsmLayout &Layout); - - typedef DenseMap<const MCSectionELF*, uint32_t> SectionIndexMapTy; - virtual void WriteSymbolTable(MCDataFragment *SymtabF, MCDataFragment *ShndxF, - const MCAssembler &Asm, - const MCAsmLayout &Layout, - const SectionIndexMapTy &SectionIndexMap); - - virtual void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout, - const MCFragment *Fragment, const MCFixup &Fixup, - MCValue Target, uint64_t &FixedValue); - - virtual uint64_t getSymbolIndexInSymbolTable(const MCAssembler &Asm, - const MCSymbol *S); - - // Map from a group section to the signature symbol - typedef DenseMap<const MCSectionELF*, const MCSymbol*> GroupMapTy; - // Map from a signature symbol to the group section - typedef DenseMap<const MCSymbol*, const MCSectionELF*> RevGroupMapTy; - - /// ComputeSymbolTable - Compute the symbol table data - /// - /// \param StringTable [out] - The string table data. - /// \param StringIndexMap [out] - Map from symbol names to offsets in the - /// string table. - virtual void ComputeSymbolTable(MCAssembler &Asm, - const SectionIndexMapTy &SectionIndexMap, - RevGroupMapTy RevGroupMap); - - virtual void ComputeIndexMap(MCAssembler &Asm, - SectionIndexMapTy &SectionIndexMap); - - virtual void WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout, - const MCSectionData &SD); - - virtual void WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout) { - for (MCAssembler::const_iterator it = Asm.begin(), - ie = Asm.end(); it != ie; ++it) { - WriteRelocation(Asm, Layout, *it); - } - } - - virtual void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout, - const SectionIndexMapTy &SectionIndexMap); - - // Create the sections that show up in the symbol table. Currently - // those are the .note.GNU-stack section and the group sections. - virtual void CreateIndexedSections(MCAssembler &Asm, MCAsmLayout &Layout, - GroupMapTy &GroupMap, - RevGroupMapTy &RevGroupMap); - - virtual void ExecutePostLayoutBinding(MCAssembler &Asm, - const MCAsmLayout &Layout); - - virtual void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags, - uint64_t Address, uint64_t Offset, - uint64_t Size, uint32_t Link, uint32_t Info, - uint64_t Alignment, uint64_t EntrySize); - - virtual void WriteRelocationsFragment(const MCAssembler &Asm, - MCDataFragment *F, - const MCSectionData *SD); - - virtual void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout); - virtual void WriteSection(MCAssembler &Asm, - const SectionIndexMapTy &SectionIndexMap, - uint32_t GroupSymbolIndex, - uint64_t Offset, uint64_t Size, uint64_t Alignment, - const MCSectionELF &Section); - - protected: - virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup, - bool IsPCRel, bool IsRelocWithSymbol, - int64_t Addend) = 0; - }; - - //===- X86ELFObjectWriter -------------------------------------------===// - - class X86ELFObjectWriter : public ELFObjectWriter { - public: - X86ELFObjectWriter(MCELFObjectTargetWriter *MOTW, - raw_ostream &_OS, - bool IsLittleEndian); - - virtual ~X86ELFObjectWriter(); - protected: - virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup, - bool IsPCRel, bool IsRelocWithSymbol, - int64_t Addend); - }; - - - //===- ARMELFObjectWriter -------------------------------------------===// - - class ARMELFObjectWriter : public ELFObjectWriter { - public: - // FIXME: MCAssembler can't yet return the Subtarget, - enum { DefaultEABIVersion = 0x05000000U }; - - ARMELFObjectWriter(MCELFObjectTargetWriter *MOTW, - raw_ostream &_OS, - bool IsLittleEndian); - - virtual ~ARMELFObjectWriter(); - - virtual void WriteEFlags(); - protected: - virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm, - const MCValue &Target, - const MCFragment &F, - bool IsBSS) const; - - virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup, - bool IsPCRel, bool IsRelocWithSymbol, - int64_t Addend); - }; - - //===- MBlazeELFObjectWriter -------------------------------------------===// - - class MBlazeELFObjectWriter : public ELFObjectWriter { - public: - MBlazeELFObjectWriter(MCELFObjectTargetWriter *MOTW, - raw_ostream &_OS, - bool IsLittleEndian); - - virtual ~MBlazeELFObjectWriter(); - protected: - virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup, - bool IsPCRel, bool IsRelocWithSymbol, - int64_t Addend); - }; -} - ELFObjectWriter::~ELFObjectWriter() {} @@ -533,7 +163,8 @@ void ELFObjectWriter::WriteSymbolEntry(MCDataFragment *SymtabF, } } -static uint64_t SymbolValue(MCSymbolData &Data, const MCAsmLayout &Layout) { +uint64_t ELFObjectWriter::SymbolValue(MCSymbolData &Data, + const MCAsmLayout &Layout) { if (Data.isCommon() && Data.isExternal()) return Data.getCommonAlignment(); @@ -579,7 +210,7 @@ void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm, // Aliases defined with .symvar copy the binding from the symbol they alias. // This is the first place we are able to copy this information. it->setExternal(SD.isExternal()); - SetBinding(*it, GetBinding(SD)); + MCELF::SetBinding(*it, MCELF::GetBinding(SD)); StringRef Rest = AliasName.substr(Pos); if (!Symbol.isUndefined() && !Rest.startswith("@@@")) @@ -605,9 +236,9 @@ void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF, bool IsReserved = Data.isCommon() || Data.getSymbol().isAbsolute() || Data.getSymbol().isVariable(); - uint8_t Binding = GetBinding(OrigData); - uint8_t Visibility = GetVisibility(OrigData); - uint8_t Type = GetType(Data); + uint8_t Binding = MCELF::GetBinding(OrigData); + uint8_t Visibility = MCELF::GetVisibility(OrigData); + uint8_t Type = MCELF::GetType(Data); uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift); uint8_t Other = Visibility; @@ -673,7 +304,7 @@ void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF, (Data.getFlags() & ELF_STB_Weak)) && "External symbol requires STB_GLOBAL or STB_WEAK flag"); WriteSymbol(SymtabF, ShndxF, MSD, Layout); - if (GetBinding(Data) == ELF::STB_LOCAL) + if (MCELF::GetBinding(Data) == ELF::STB_LOCAL) LastLocalSymbolIndex++; } @@ -681,7 +312,7 @@ void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF, ELFSymbolData &MSD = UndefinedSymbolData[i]; MCSymbolData &Data = *MSD.SymbolData; WriteSymbol(SymtabF, ShndxF, MSD, Layout); - if (GetBinding(Data) == ELF::STB_LOCAL) + if (MCELF::GetBinding(Data) == ELF::STB_LOCAL) LastLocalSymbolIndex++; } } @@ -798,7 +429,7 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm, FixedValue = Value; unsigned Type = GetRelocType(Target, Fixup, IsPCRel, (RelocSymbol != 0), Addend); - + uint64_t RelocOffset = Layout.getFragmentOffset(Fragment) + Fixup.getOffset(); @@ -816,8 +447,9 @@ ELFObjectWriter::getSymbolIndexInSymbolTable(const MCAssembler &Asm, return SD.getIndex(); } -static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data, - bool Used, bool Renamed) { +bool ELFObjectWriter::isInSymtab(const MCAssembler &Asm, + const MCSymbolData &Data, + bool Used, bool Renamed) { if (Data.getFlags() & ELF_Other_Weakref) return false; @@ -836,7 +468,7 @@ static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data, if (Symbol.isVariable() && !A.isVariable() && A.isUndefined()) return false; - bool IsGlobal = GetBinding(Data) == ELF::STB_GLOBAL; + bool IsGlobal = MCELF::GetBinding(Data) == ELF::STB_GLOBAL; if (!Symbol.isVariable() && Symbol.isUndefined() && !IsGlobal) return false; @@ -849,8 +481,8 @@ static bool isInSymtab(const MCAssembler &Asm, const MCSymbolData &Data, return true; } -static bool isLocal(const MCSymbolData &Data, bool isSignature, - bool isUsedInReloc) { +bool ELFObjectWriter::isLocal(const MCSymbolData &Data, bool isSignature, + bool isUsedInReloc) { if (Data.isExternal()) return false; @@ -868,7 +500,8 @@ static bool isLocal(const MCSymbolData &Data, bool isSignature, } void ELFObjectWriter::ComputeIndexMap(MCAssembler &Asm, - SectionIndexMapTy &SectionIndexMap) { + SectionIndexMapTy &SectionIndexMap, + const RelMapTy &RelMap) { unsigned Index = 1; for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it) { @@ -883,31 +516,37 @@ void ELFObjectWriter::ComputeIndexMap(MCAssembler &Asm, ie = Asm.end(); it != ie; ++it) { const MCSectionELF &Section = static_cast<const MCSectionELF &>(it->getSection()); - if (Section.getType() == ELF::SHT_GROUP) + if (Section.getType() == ELF::SHT_GROUP || + Section.getType() == ELF::SHT_REL || + Section.getType() == ELF::SHT_RELA) continue; SectionIndexMap[&Section] = Index++; + const MCSectionELF *RelSection = RelMap.lookup(&Section); + if (RelSection) + SectionIndexMap[RelSection] = Index++; } } void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm, const SectionIndexMapTy &SectionIndexMap, - RevGroupMapTy RevGroupMap) { + RevGroupMapTy RevGroupMap, + unsigned NumRegularSections) { // 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); - SetBinding(Data, ELF::STB_GLOBAL); + MCELF::SetBinding(Data, ELF::STB_GLOBAL); } - // Build section lookup table. - int NumRegularSections = Asm.size(); - // Index 0 is always the empty string. StringMap<uint64_t> StringIndexMap; StringTable += '\x00'; + // FIXME: We could optimize suffixes in strtab in the same way we + // optimize them in shstrtab. + // Add the data for the symbols. for (MCAssembler::symbol_iterator it = Asm.symbol_begin(), ie = Asm.symbol_end(); it != ie; ++it) { @@ -929,14 +568,14 @@ void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm, // Undefined symbols are global, but this is the first place we // are able to set it. bool Local = isLocal(*it, isSignature, Used); - if (!Local && GetBinding(*it) == ELF::STB_LOCAL) { + if (!Local && MCELF::GetBinding(*it) == ELF::STB_LOCAL) { MCSymbolData &SD = Asm.getSymbolData(RefSymbol); - SetBinding(*it, ELF::STB_GLOBAL); - SetBinding(SD, ELF::STB_GLOBAL); + MCELF::SetBinding(*it, ELF::STB_GLOBAL); + MCELF::SetBinding(SD, ELF::STB_GLOBAL); } if (RefSymbol.isUndefined() && !Used && WeakrefUsed) - SetBinding(*it, ELF::STB_WEAK); + MCELF::SetBinding(*it, ELF::STB_WEAK); if (it->isCommon()) { assert(!Local); @@ -1004,11 +643,16 @@ void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm, UndefinedSymbolData[i].SymbolData->setIndex(Index++); } -void ELFObjectWriter::WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout, - const MCSectionData &SD) { - if (!Relocations[&SD].empty()) { +void ELFObjectWriter::CreateRelocationSections(MCAssembler &Asm, + MCAsmLayout &Layout, + RelMapTy &RelMap) { + for (MCAssembler::const_iterator it = Asm.begin(), + ie = Asm.end(); it != ie; ++it) { + const MCSectionData &SD = *it; + if (Relocations[&SD].empty()) + continue; + MCContext &Ctx = Asm.getContext(); - const MCSectionELF *RelaSection; const MCSectionELF &Section = static_cast<const MCSectionELF&>(SD.getSection()); @@ -1022,17 +666,32 @@ void ELFObjectWriter::WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout, else EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel); - RelaSection = Ctx.getELFSection(RelaSectionName, hasRelocationAddend() ? - ELF::SHT_RELA : ELF::SHT_REL, 0, - SectionKind::getReadOnly(), - EntrySize, ""); + const MCSectionELF *RelaSection = + Ctx.getELFSection(RelaSectionName, hasRelocationAddend() ? + ELF::SHT_RELA : ELF::SHT_REL, 0, + SectionKind::getReadOnly(), + EntrySize, ""); + RelMap[&Section] = RelaSection; + Asm.getOrCreateSectionData(*RelaSection); + } +} +void ELFObjectWriter::WriteRelocations(MCAssembler &Asm, MCAsmLayout &Layout, + const RelMapTy &RelMap) { + for (MCAssembler::const_iterator it = Asm.begin(), + ie = Asm.end(); it != ie; ++it) { + const MCSectionData &SD = *it; + const MCSectionELF &Section = + static_cast<const MCSectionELF&>(SD.getSection()); + + const MCSectionELF *RelaSection = RelMap.lookup(&Section); + if (!RelaSection) + continue; MCSectionData &RelaSD = Asm.getOrCreateSectionData(*RelaSection); RelaSD.setAlignment(is64Bit() ? 8 : 4); MCDataFragment *F = new MCDataFragment(&RelaSD); - - WriteRelocationsFragment(Asm, F, &SD); + WriteRelocationsFragment(Asm, F, &*it); } } @@ -1092,9 +751,28 @@ void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm, } } +static int compareBySuffix(const void *a, const void *b) { + const MCSectionELF *secA = *static_cast<const MCSectionELF* const *>(a); + const MCSectionELF *secB = *static_cast<const MCSectionELF* const *>(b); + const StringRef &NameA = secA->getSectionName(); + const StringRef &NameB = secB->getSectionName(); + const unsigned sizeA = NameA.size(); + const unsigned sizeB = NameB.size(); + const unsigned len = std::min(sizeA, sizeB); + for (unsigned int i = 0; i < len; ++i) { + char ca = NameA[sizeA - i - 1]; + char cb = NameB[sizeB - i - 1]; + if (ca != cb) + return cb - ca; + } + + return sizeB - sizeA; +} + void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout, - const SectionIndexMapTy &SectionIndexMap) { + SectionIndexMapTy &SectionIndexMap, + const RelMapTy &RelMap) { MCContext &Ctx = Asm.getContext(); MCDataFragment *F; @@ -1106,7 +784,6 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm, SectionKind::getReadOnly()); MCSectionData &ShstrtabSD = Asm.getOrCreateSectionData(*ShstrtabSection); ShstrtabSD.setAlignment(1); - ShstrtabIndex = Asm.size(); const MCSectionELF *SymtabSection = Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0, @@ -1114,7 +791,6 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm, EntrySize, ""); MCSectionData &SymtabSD = Asm.getOrCreateSectionData(*SymtabSection); SymtabSD.setAlignment(is64Bit() ? 8 : 4); - SymbolTableIndex = Asm.size(); MCSectionData *SymtabShndxSD = NULL; @@ -1126,14 +802,17 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm, SymtabShndxSD->setAlignment(4); } - const MCSection *StrtabSection; + const MCSectionELF *StrtabSection; StrtabSection = Ctx.getELFSection(".strtab", ELF::SHT_STRTAB, 0, SectionKind::getReadOnly()); MCSectionData &StrtabSD = Asm.getOrCreateSectionData(*StrtabSection); StrtabSD.setAlignment(1); - StringTableIndex = Asm.size(); - WriteRelocations(Asm, Layout); + ComputeIndexMap(Asm, SectionIndexMap, RelMap); + + ShstrtabIndex = SectionIndexMap.lookup(ShstrtabSection); + SymbolTableIndex = SectionIndexMap.lookup(SymtabSection); + StringTableIndex = SectionIndexMap.lookup(StrtabSection); // Symbol table F = new MCDataFragment(&SymtabSD); @@ -1148,6 +827,15 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm, F = new MCDataFragment(&ShstrtabSD); + std::vector<const MCSectionELF*> Sections; + for (MCAssembler::const_iterator it = Asm.begin(), + ie = Asm.end(); it != ie; ++it) { + const MCSectionELF &Section = + static_cast<const MCSectionELF&>(it->getSection()); + Sections.push_back(&Section); + } + array_pod_sort(Sections.begin(), Sections.end(), compareBySuffix); + // Section header string table. // // The first entry of a string table holds a null character so skip @@ -1155,22 +843,20 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm, uint64_t Index = 1; F->getContents() += '\x00'; - StringMap<uint64_t> SecStringMap; - for (MCAssembler::const_iterator it = Asm.begin(), - ie = Asm.end(); it != ie; ++it) { - const MCSectionELF &Section = - static_cast<const MCSectionELF&>(it->getSection()); - // FIXME: We could merge suffixes like in .text and .rela.text. + for (unsigned int I = 0, E = Sections.size(); I != E; ++I) { + const MCSectionELF &Section = *Sections[I]; StringRef Name = Section.getSectionName(); - if (SecStringMap.count(Name)) { - SectionStringTableIndex[&Section] = SecStringMap[Name]; - continue; + if (I != 0) { + StringRef PreviousName = Sections[I - 1]->getSectionName(); + if (PreviousName.endswith(Name)) { + SectionStringTableIndex[&Section] = Index - Name.size() - 1; + continue; + } } // Remember the index into the string table so we can write it // into the sh_name field of the section header table. SectionStringTableIndex[&Section] = Index; - SecStringMap[Name] = Index; Index += Name.size() + 1; F->getContents() += Name; @@ -1181,7 +867,9 @@ void ELFObjectWriter::CreateMetadataSections(MCAssembler &Asm, void ELFObjectWriter::CreateIndexedSections(MCAssembler &Asm, MCAsmLayout &Layout, GroupMapTy &GroupMap, - RevGroupMapTy &RevGroupMap) { + RevGroupMapTy &RevGroupMap, + SectionIndexMapTy &SectionIndexMap, + const RelMapTy &RelMap) { // Create the .note.GNU-stack section if needed. MCContext &Ctx = Asm.getContext(); if (Asm.getNoExecStack()) { @@ -1212,11 +900,11 @@ void ELFObjectWriter::CreateIndexedSections(MCAssembler &Asm, GroupMap[Group] = SignatureSymbol; } + ComputeIndexMap(Asm, SectionIndexMap, RelMap); + // Add sections to the groups - unsigned Index = 1; - unsigned NumGroups = RevGroupMap.size(); for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end(); - it != ie; ++it, ++Index) { + it != ie; ++it) { const MCSectionELF &Section = static_cast<const MCSectionELF&>(it->getSection()); if (!(Section.getFlags() & ELF::SHF_GROUP)) @@ -1225,7 +913,8 @@ void ELFObjectWriter::CreateIndexedSections(MCAssembler &Asm, MCSectionData &Data = Asm.getOrCreateSectionData(*Group); // FIXME: we could use the previous fragment MCDataFragment *F = new MCDataFragment(&Data); - String32(*F, NumGroups + Index); + unsigned Index = SectionIndexMap.lookup(&Section); + String32(*F, Index); } } @@ -1304,12 +993,12 @@ void ELFObjectWriter::WriteSection(MCAssembler &Asm, Alignment, Section.getEntrySize()); } -static bool IsELFMetaDataSection(const MCSectionData &SD) { +bool ELFObjectWriter::IsELFMetaDataSection(const MCSectionData &SD) { return SD.getOrdinal() == ~UINT32_C(0) && !SD.getSection().isVirtualSection(); } -static uint64_t DataSectionSize(const MCSectionData &SD) { +uint64_t ELFObjectWriter::DataSectionSize(const MCSectionData &SD) { uint64_t Ret = 0; for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e; ++i) { @@ -1320,26 +1009,112 @@ static uint64_t DataSectionSize(const MCSectionData &SD) { return Ret; } -static uint64_t GetSectionFileSize(const MCAsmLayout &Layout, - const MCSectionData &SD) { +uint64_t ELFObjectWriter::GetSectionFileSize(const MCAsmLayout &Layout, + const MCSectionData &SD) { if (IsELFMetaDataSection(SD)) return DataSectionSize(SD); return Layout.getSectionFileSize(&SD); } -static uint64_t GetSectionAddressSize(const MCAsmLayout &Layout, - const MCSectionData &SD) { +uint64_t ELFObjectWriter::GetSectionAddressSize(const MCAsmLayout &Layout, + const MCSectionData &SD) { if (IsELFMetaDataSection(SD)) return DataSectionSize(SD); return Layout.getSectionAddressSize(&SD); } -static void WriteDataSectionData(ELFObjectWriter *W, const MCSectionData &SD) { - for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e; - ++i) { - const MCFragment &F = *i; - assert(F.getKind() == MCFragment::FT_Data); - W->WriteBytes(cast<MCDataFragment>(F).getContents().str()); +void ELFObjectWriter::WriteDataSectionData(MCAssembler &Asm, + const MCAsmLayout &Layout, + const MCSectionELF &Section) { + uint64_t FileOff = OS.tell(); + const MCSectionData &SD = Asm.getOrCreateSectionData(Section); + + uint64_t Padding = OffsetToAlignment(FileOff, SD.getAlignment()); + WriteZeros(Padding); + FileOff += Padding; + + FileOff += GetSectionFileSize(Layout, SD); + + if (IsELFMetaDataSection(SD)) { + for (MCSectionData::const_iterator i = SD.begin(), e = SD.end(); i != e; + ++i) { + const MCFragment &F = *i; + assert(F.getKind() == MCFragment::FT_Data); + WriteBytes(cast<MCDataFragment>(F).getContents().str()); + } + } else { + Asm.WriteSectionData(&SD, Layout); + } +} + +void ELFObjectWriter::WriteSectionHeader(MCAssembler &Asm, + const GroupMapTy &GroupMap, + const MCAsmLayout &Layout, + const SectionIndexMapTy &SectionIndexMap, + const SectionOffsetMapTy &SectionOffsetMap) { + const unsigned NumSections = Asm.size() + 1; + + std::vector<const MCSectionELF*> Sections; + Sections.resize(NumSections - 1); + + for (SectionIndexMapTy::const_iterator i= + SectionIndexMap.begin(), e = SectionIndexMap.end(); i != e; ++i) { + const std::pair<const MCSectionELF*, uint32_t> &p = *i; + Sections[p.second - 1] = p.first; + } + + // Null section first. + uint64_t FirstSectionSize = + NumSections >= ELF::SHN_LORESERVE ? NumSections : 0; + uint32_t FirstSectionLink = + ShstrtabIndex >= ELF::SHN_LORESERVE ? ShstrtabIndex : 0; + WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, FirstSectionLink, 0, 0, 0); + + for (unsigned i = 0; i < NumSections - 1; ++i) { + const MCSectionELF &Section = *Sections[i]; + const MCSectionData &SD = Asm.getOrCreateSectionData(Section); + uint32_t GroupSymbolIndex; + if (Section.getType() != ELF::SHT_GROUP) + GroupSymbolIndex = 0; + else + GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm, + GroupMap.lookup(&Section)); + + uint64_t Size = GetSectionAddressSize(Layout, SD); + + WriteSection(Asm, SectionIndexMap, GroupSymbolIndex, + SectionOffsetMap.lookup(&Section), Size, + SD.getAlignment(), Section); + } +} + +void ELFObjectWriter::ComputeSectionOrder(MCAssembler &Asm, + std::vector<const MCSectionELF*> &Sections) { + for (MCAssembler::iterator it = Asm.begin(), + ie = Asm.end(); it != ie; ++it) { + const MCSectionELF &Section = + static_cast<const MCSectionELF &>(it->getSection()); + if (Section.getType() == ELF::SHT_GROUP) + Sections.push_back(&Section); + } + + for (MCAssembler::iterator it = Asm.begin(), + ie = Asm.end(); it != ie; ++it) { + const MCSectionELF &Section = + static_cast<const MCSectionELF &>(it->getSection()); + if (Section.getType() != ELF::SHT_GROUP && + Section.getType() != ELF::SHT_REL && + Section.getType() != ELF::SHT_RELA) + Sections.push_back(&Section); + } + + for (MCAssembler::iterator it = Asm.begin(), + ie = Asm.end(); it != ie; ++it) { + const MCSectionELF &Section = + static_cast<const MCSectionELF &>(it->getSection()); + if (Section.getType() == ELF::SHT_REL || + Section.getType() == ELF::SHT_RELA) + Sections.push_back(&Section); } } @@ -1347,107 +1122,108 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout) { GroupMapTy GroupMap; RevGroupMapTy RevGroupMap; - CreateIndexedSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap, - RevGroupMap); - SectionIndexMapTy SectionIndexMap; - ComputeIndexMap(Asm, SectionIndexMap); + unsigned NumUserSections = Asm.size(); + + DenseMap<const MCSectionELF*, const MCSectionELF*> RelMap; + CreateRelocationSections(Asm, const_cast<MCAsmLayout&>(Layout), RelMap); + + const unsigned NumUserAndRelocSections = Asm.size(); + CreateIndexedSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap, + RevGroupMap, SectionIndexMap, RelMap); + const unsigned AllSections = Asm.size(); + const unsigned NumIndexedSections = AllSections - NumUserAndRelocSections; + + unsigned NumRegularSections = NumUserSections + NumIndexedSections; // Compute symbol table information. - ComputeSymbolTable(Asm, SectionIndexMap, RevGroupMap); + ComputeSymbolTable(Asm, SectionIndexMap, RevGroupMap, NumRegularSections); + + + WriteRelocations(Asm, const_cast<MCAsmLayout&>(Layout), RelMap); CreateMetadataSections(const_cast<MCAssembler&>(Asm), const_cast<MCAsmLayout&>(Layout), - SectionIndexMap); - - // Update to include the metadata sections. - ComputeIndexMap(Asm, SectionIndexMap); + SectionIndexMap, + RelMap); - // Add 1 for the null section. - unsigned NumSections = Asm.size() + 1; uint64_t NaturalAlignment = is64Bit() ? 8 : 4; uint64_t HeaderSize = is64Bit() ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr); uint64_t FileOff = HeaderSize; std::vector<const MCSectionELF*> Sections; - Sections.resize(NumSections); - - for (SectionIndexMapTy::const_iterator i= - SectionIndexMap.begin(), e = SectionIndexMap.end(); i != e; ++i) { - const std::pair<const MCSectionELF*, uint32_t> &p = *i; - Sections[p.second] = p.first; - } - - for (unsigned i = 1; i < NumSections; ++i) { + ComputeSectionOrder(Asm, Sections); + unsigned NumSections = Sections.size(); + SectionOffsetMapTy SectionOffsetMap; + for (unsigned i = 0; i < NumRegularSections + 1; ++i) { const MCSectionELF &Section = *Sections[i]; const MCSectionData &SD = Asm.getOrCreateSectionData(Section); FileOff = RoundUpToAlignment(FileOff, SD.getAlignment()); + // Remember the offset into the file for this section. + SectionOffsetMap[&Section] = FileOff; + // Get the size of the section in the output file (including padding). FileOff += GetSectionFileSize(Layout, SD); } FileOff = RoundUpToAlignment(FileOff, NaturalAlignment); - // Write out the ELF header ... - WriteHeader(FileOff - HeaderSize, NumSections); - - FileOff = HeaderSize; + const unsigned SectionHeaderOffset = FileOff - HeaderSize; - // ... then all of the sections ... - DenseMap<const MCSection*, uint64_t> SectionOffsetMap; + uint64_t SectionHeaderEntrySize = is64Bit() ? + sizeof(ELF::Elf64_Shdr) : sizeof(ELF::Elf32_Shdr); + FileOff += (NumSections + 1) * SectionHeaderEntrySize; - for (unsigned i = 1; i < NumSections; ++i) { + for (unsigned i = NumRegularSections + 1; i < NumSections; ++i) { const MCSectionELF &Section = *Sections[i]; const MCSectionData &SD = Asm.getOrCreateSectionData(Section); - uint64_t Padding = OffsetToAlignment(FileOff, SD.getAlignment()); - WriteZeros(Padding); - FileOff += Padding; + FileOff = RoundUpToAlignment(FileOff, SD.getAlignment()); // Remember the offset into the file for this section. SectionOffsetMap[&Section] = FileOff; + // Get the size of the section in the output file (including padding). FileOff += GetSectionFileSize(Layout, SD); - - if (IsELFMetaDataSection(SD)) - WriteDataSectionData(this, SD); - else - Asm.WriteSectionData(&SD, Layout); } + // Write out the ELF header ... + WriteHeader(SectionHeaderOffset, NumSections + 1); + + // ... then the regular sections ... + // + because of .shstrtab + for (unsigned i = 0; i < NumRegularSections + 1; ++i) + WriteDataSectionData(Asm, Layout, *Sections[i]); + + FileOff = OS.tell(); uint64_t Padding = OffsetToAlignment(FileOff, NaturalAlignment); WriteZeros(Padding); - FileOff += Padding; - // ... and then the section header table. - // Should we align the section header table? - // - // Null section first. - uint64_t FirstSectionSize = - NumSections >= ELF::SHN_LORESERVE ? NumSections : 0; - uint32_t FirstSectionLink = - ShstrtabIndex >= ELF::SHN_LORESERVE ? ShstrtabIndex : 0; - WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, FirstSectionLink, 0, 0, 0); + // ... then the section header table ... + WriteSectionHeader(Asm, GroupMap, Layout, SectionIndexMap, + SectionOffsetMap); - for (unsigned i = 1; i < NumSections; ++i) { - const MCSectionELF &Section = *Sections[i]; - const MCSectionData &SD = Asm.getOrCreateSectionData(Section); - uint32_t GroupSymbolIndex; - if (Section.getType() != ELF::SHT_GROUP) - GroupSymbolIndex = 0; - else - GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm, GroupMap[&Section]); + FileOff = OS.tell(); - uint64_t Size = GetSectionAddressSize(Layout, SD); + // ... and then the remainting sections ... + for (unsigned i = NumRegularSections + 1; i < NumSections; ++i) + WriteDataSectionData(Asm, Layout, *Sections[i]); +} - WriteSection(Asm, SectionIndexMap, GroupSymbolIndex, - SectionOffsetMap[&Section], Size, - SD.getAlignment(), Section); - } +bool +ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm, + const MCSymbolData &DataA, + const MCFragment &FB, + bool InSet, + bool IsPCRel) const { + if (DataA.getFlags() & ELF_STB_Weak) + return false; + return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl( + Asm, DataA, FB,InSet, IsPCRel); } MCObjectWriter *llvm::createELFObjectWriter(MCELFObjectTargetWriter *MOTW, @@ -1700,13 +1476,17 @@ unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target, if (IsPCRel) { switch ((unsigned)Fixup.getKind()) { default: llvm_unreachable("invalid fixup kind!"); + + case FK_Data_8: Type = ELF::R_X86_64_PC64; break; + case FK_Data_4: Type = ELF::R_X86_64_PC32; break; + case FK_Data_2: Type = ELF::R_X86_64_PC16; break; + case FK_PCRel_8: assert(Modifier == MCSymbolRefExpr::VK_None); Type = ELF::R_X86_64_PC64; break; case X86::reloc_signed_4byte: case X86::reloc_riprel_4byte_movq_load: - case FK_Data_4: // FIXME? case X86::reloc_riprel_4byte: case FK_PCRel_4: switch (Modifier) { |
