| //===- llvm/MC/WinCOFFObjectWriter.cpp ------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains an implementation of a Win32 COFF object file writer. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/ADT/DenseSet.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/SmallString.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/ADT/Twine.h" |
| #include "llvm/BinaryFormat/COFF.h" |
| #include "llvm/MC/MCAsmLayout.h" |
| #include "llvm/MC/MCAssembler.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCExpr.h" |
| #include "llvm/MC/MCFixup.h" |
| #include "llvm/MC/MCFragment.h" |
| #include "llvm/MC/MCObjectWriter.h" |
| #include "llvm/MC/MCSection.h" |
| #include "llvm/MC/MCSectionCOFF.h" |
| #include "llvm/MC/MCSymbol.h" |
| #include "llvm/MC/MCSymbolCOFF.h" |
| #include "llvm/MC/MCValue.h" |
| #include "llvm/MC/MCWinCOFFObjectWriter.h" |
| #include "llvm/MC/StringTableBuilder.h" |
| #include "llvm/Support/CRC.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/EndianStream.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/LEB128.h" |
| #include "llvm/Support/MathExtras.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <algorithm> |
| #include <cassert> |
| #include <cstdint> |
| #include <cstring> |
| #include <ctime> |
| #include <memory> |
| #include <string> |
| #include <vector> |
| |
| using namespace llvm; |
| using llvm::support::endian::write32le; |
| |
| #define DEBUG_TYPE "WinCOFFObjectWriter" |
| |
| namespace { |
| |
| constexpr int OffsetLabelIntervalBits = 20; |
| |
| using name = SmallString<COFF::NameSize>; |
| |
| enum AuxiliaryType { |
| ATWeakExternal, |
| ATFile, |
| ATSectionDefinition |
| }; |
| |
| struct AuxSymbol { |
| AuxiliaryType AuxType; |
| COFF::Auxiliary Aux; |
| }; |
| |
| class COFFSection; |
| |
| class COFFSymbol { |
| public: |
| COFF::symbol Data = {}; |
| |
| using AuxiliarySymbols = SmallVector<AuxSymbol, 1>; |
| |
| name Name; |
| int Index = 0; |
| AuxiliarySymbols Aux; |
| COFFSymbol *Other = nullptr; |
| COFFSection *Section = nullptr; |
| int Relocations = 0; |
| const MCSymbol *MC = nullptr; |
| |
| COFFSymbol(StringRef Name) : Name(Name) {} |
| |
| void set_name_offset(uint32_t Offset); |
| |
| int64_t getIndex() const { return Index; } |
| void setIndex(int Value) { |
| Index = Value; |
| if (MC) |
| MC->setIndex(static_cast<uint32_t>(Value)); |
| } |
| }; |
| |
| // This class contains staging data for a COFF relocation entry. |
| struct COFFRelocation { |
| COFF::relocation Data; |
| COFFSymbol *Symb = nullptr; |
| |
| COFFRelocation() = default; |
| |
| static size_t size() { return COFF::RelocationSize; } |
| }; |
| |
| using relocations = std::vector<COFFRelocation>; |
| |
| class COFFSection { |
| public: |
| COFF::section Header = {}; |
| |
| std::string Name; |
| int Number = 0; |
| MCSectionCOFF const *MCSection = nullptr; |
| COFFSymbol *Symbol = nullptr; |
| relocations Relocations; |
| |
| COFFSection(StringRef Name) : Name(std::string(Name)) {} |
| |
| SmallVector<COFFSymbol *, 1> OffsetSymbols; |
| }; |
| |
| class WinCOFFObjectWriter : public MCObjectWriter { |
| public: |
| support::endian::Writer W; |
| |
| using symbols = std::vector<std::unique_ptr<COFFSymbol>>; |
| using sections = std::vector<std::unique_ptr<COFFSection>>; |
| |
| using symbol_map = DenseMap<MCSymbol const *, COFFSymbol *>; |
| using section_map = DenseMap<MCSection const *, COFFSection *>; |
| |
| using symbol_list = DenseSet<COFFSymbol *>; |
| |
| std::unique_ptr<MCWinCOFFObjectTargetWriter> TargetObjectWriter; |
| |
| // Root level file contents. |
| COFF::header Header = {}; |
| sections Sections; |
| symbols Symbols; |
| StringTableBuilder Strings{StringTableBuilder::WinCOFF}; |
| |
| // Maps used during object file creation. |
| section_map SectionMap; |
| symbol_map SymbolMap; |
| |
| symbol_list WeakDefaults; |
| |
| bool UseBigObj; |
| bool UseOffsetLabels = false; |
| |
| MCSectionCOFF *AddrsigSection = nullptr; |
| |
| MCSectionCOFF *CGProfileSection = nullptr; |
| |
| WinCOFFObjectWriter(std::unique_ptr<MCWinCOFFObjectTargetWriter> MOTW, |
| raw_pwrite_stream &OS); |
| |
| void reset() override { |
| memset(&Header, 0, sizeof(Header)); |
| Header.Machine = TargetObjectWriter->getMachine(); |
| Sections.clear(); |
| Symbols.clear(); |
| Strings.clear(); |
| SectionMap.clear(); |
| SymbolMap.clear(); |
| WeakDefaults.clear(); |
| MCObjectWriter::reset(); |
| } |
| |
| COFFSymbol *createSymbol(StringRef Name); |
| COFFSymbol *GetOrCreateCOFFSymbol(const MCSymbol *Symbol); |
| COFFSection *createSection(StringRef Name); |
| |
| void defineSection(MCSectionCOFF const &Sec, const MCAsmLayout &Layout); |
| |
| COFFSymbol *getLinkedSymbol(const MCSymbol &Symbol); |
| void DefineSymbol(const MCSymbol &Symbol, MCAssembler &Assembler, |
| const MCAsmLayout &Layout); |
| |
| void SetSymbolName(COFFSymbol &S); |
| void SetSectionName(COFFSection &S); |
| |
| bool IsPhysicalSection(COFFSection *S); |
| |
| // Entity writing methods. |
| |
| void WriteFileHeader(const COFF::header &Header); |
| void WriteSymbol(const COFFSymbol &S); |
| void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S); |
| void writeSectionHeaders(); |
| void WriteRelocation(const COFF::relocation &R); |
| uint32_t writeSectionContents(MCAssembler &Asm, const MCAsmLayout &Layout, |
| const MCSection &MCSec); |
| void writeSection(MCAssembler &Asm, const MCAsmLayout &Layout, |
| const COFFSection &Sec); |
| |
| // MCObjectWriter interface implementation. |
| |
| void executePostLayoutBinding(MCAssembler &Asm, |
| const MCAsmLayout &Layout) override; |
| |
| bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm, |
| const MCSymbol &SymA, |
| const MCFragment &FB, bool InSet, |
| bool IsPCRel) const override; |
| |
| void recordRelocation(MCAssembler &Asm, const MCAsmLayout &Layout, |
| const MCFragment *Fragment, const MCFixup &Fixup, |
| MCValue Target, uint64_t &FixedValue) override; |
| |
| void createFileSymbols(MCAssembler &Asm); |
| void setWeakDefaultNames(); |
| void assignSectionNumbers(); |
| void assignFileOffsets(MCAssembler &Asm, const MCAsmLayout &Layout); |
| |
| uint64_t writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) override; |
| }; |
| |
| } // end anonymous namespace |
| |
| //------------------------------------------------------------------------------ |
| // Symbol class implementation |
| |
| // In the case that the name does not fit within 8 bytes, the offset |
| // into the string table is stored in the last 4 bytes instead, leaving |
| // the first 4 bytes as 0. |
| void COFFSymbol::set_name_offset(uint32_t Offset) { |
| write32le(Data.Name + 0, 0); |
| write32le(Data.Name + 4, Offset); |
| } |
| |
| //------------------------------------------------------------------------------ |
| // WinCOFFObjectWriter class implementation |
| |
| WinCOFFObjectWriter::WinCOFFObjectWriter( |
| std::unique_ptr<MCWinCOFFObjectTargetWriter> MOTW, raw_pwrite_stream &OS) |
| : W(OS, support::little), TargetObjectWriter(std::move(MOTW)) { |
| Header.Machine = TargetObjectWriter->getMachine(); |
| // Some relocations on ARM64 (the 21 bit ADRP relocations) have a slightly |
| // limited range for the immediate offset (+/- 1 MB); create extra offset |
| // label symbols with regular intervals to allow referencing a |
| // non-temporary symbol that is close enough. |
| UseOffsetLabels = Header.Machine == COFF::IMAGE_FILE_MACHINE_ARM64; |
| } |
| |
| COFFSymbol *WinCOFFObjectWriter::createSymbol(StringRef Name) { |
| Symbols.push_back(std::make_unique<COFFSymbol>(Name)); |
| return Symbols.back().get(); |
| } |
| |
| COFFSymbol *WinCOFFObjectWriter::GetOrCreateCOFFSymbol(const MCSymbol *Symbol) { |
| COFFSymbol *&Ret = SymbolMap[Symbol]; |
| if (!Ret) |
| Ret = createSymbol(Symbol->getName()); |
| return Ret; |
| } |
| |
| COFFSection *WinCOFFObjectWriter::createSection(StringRef Name) { |
| Sections.emplace_back(std::make_unique<COFFSection>(Name)); |
| return Sections.back().get(); |
| } |
| |
| static uint32_t getAlignment(const MCSectionCOFF &Sec) { |
| switch (Sec.getAlign().value()) { |
| case 1: |
| return COFF::IMAGE_SCN_ALIGN_1BYTES; |
| case 2: |
| return COFF::IMAGE_SCN_ALIGN_2BYTES; |
| case 4: |
| return COFF::IMAGE_SCN_ALIGN_4BYTES; |
| case 8: |
| return COFF::IMAGE_SCN_ALIGN_8BYTES; |
| case 16: |
| return COFF::IMAGE_SCN_ALIGN_16BYTES; |
| case 32: |
| return COFF::IMAGE_SCN_ALIGN_32BYTES; |
| case 64: |
| return COFF::IMAGE_SCN_ALIGN_64BYTES; |
| case 128: |
| return COFF::IMAGE_SCN_ALIGN_128BYTES; |
| case 256: |
| return COFF::IMAGE_SCN_ALIGN_256BYTES; |
| case 512: |
| return COFF::IMAGE_SCN_ALIGN_512BYTES; |
| case 1024: |
| return COFF::IMAGE_SCN_ALIGN_1024BYTES; |
| case 2048: |
| return COFF::IMAGE_SCN_ALIGN_2048BYTES; |
| case 4096: |
| return COFF::IMAGE_SCN_ALIGN_4096BYTES; |
| case 8192: |
| return COFF::IMAGE_SCN_ALIGN_8192BYTES; |
| } |
| llvm_unreachable("unsupported section alignment"); |
| } |
| |
| /// This function takes a section data object from the assembler |
| /// and creates the associated COFF section staging object. |
| void WinCOFFObjectWriter::defineSection(const MCSectionCOFF &MCSec, |
| const MCAsmLayout &Layout) { |
| COFFSection *Section = createSection(MCSec.getName()); |
| COFFSymbol *Symbol = createSymbol(MCSec.getName()); |
| Section->Symbol = Symbol; |
| Symbol->Section = Section; |
| Symbol->Data.StorageClass = COFF::IMAGE_SYM_CLASS_STATIC; |
| |
| // Create a COMDAT symbol if needed. |
| if (MCSec.getSelection() != COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) { |
| if (const MCSymbol *S = MCSec.getCOMDATSymbol()) { |
| COFFSymbol *COMDATSymbol = GetOrCreateCOFFSymbol(S); |
| if (COMDATSymbol->Section) |
| report_fatal_error("two sections have the same comdat"); |
| COMDATSymbol->Section = Section; |
| } |
| } |
| |
| // In this case the auxiliary symbol is a Section Definition. |
| Symbol->Aux.resize(1); |
| Symbol->Aux[0] = {}; |
| Symbol->Aux[0].AuxType = ATSectionDefinition; |
| Symbol->Aux[0].Aux.SectionDefinition.Selection = MCSec.getSelection(); |
| |
| // Set section alignment. |
| Section->Header.Characteristics = MCSec.getCharacteristics(); |
| Section->Header.Characteristics |= getAlignment(MCSec); |
| |
| // Bind internal COFF section to MC section. |
| Section->MCSection = &MCSec; |
| SectionMap[&MCSec] = Section; |
| |
| if (UseOffsetLabels && !MCSec.getFragmentList().empty()) { |
| const uint32_t Interval = 1 << OffsetLabelIntervalBits; |
| uint32_t N = 1; |
| for (uint32_t Off = Interval, E = Layout.getSectionAddressSize(&MCSec); |
| Off < E; Off += Interval) { |
| auto Name = ("$L" + MCSec.getName() + "_" + Twine(N++)).str(); |
| COFFSymbol *Label = createSymbol(Name); |
| Label->Section = Section; |
| Label->Data.StorageClass = COFF::IMAGE_SYM_CLASS_LABEL; |
| Label->Data.Value = Off; |
| Section->OffsetSymbols.push_back(Label); |
| } |
| } |
| } |
| |
| static uint64_t getSymbolValue(const MCSymbol &Symbol, |
| const MCAsmLayout &Layout) { |
| if (Symbol.isCommon() && Symbol.isExternal()) |
| return Symbol.getCommonSize(); |
| |
| uint64_t Res; |
| if (!Layout.getSymbolOffset(Symbol, Res)) |
| return 0; |
| |
| return Res; |
| } |
| |
| COFFSymbol *WinCOFFObjectWriter::getLinkedSymbol(const MCSymbol &Symbol) { |
| if (!Symbol.isVariable()) |
| return nullptr; |
| |
| const MCSymbolRefExpr *SymRef = |
| dyn_cast<MCSymbolRefExpr>(Symbol.getVariableValue()); |
| if (!SymRef) |
| return nullptr; |
| |
| const MCSymbol &Aliasee = SymRef->getSymbol(); |
| if (Aliasee.isUndefined() || Aliasee.isExternal()) |
| return GetOrCreateCOFFSymbol(&Aliasee); |
| else |
| return nullptr; |
| } |
| |
| /// This function takes a symbol data object from the assembler |
| /// and creates the associated COFF symbol staging object. |
| void WinCOFFObjectWriter::DefineSymbol(const MCSymbol &MCSym, |
| MCAssembler &Assembler, |
| const MCAsmLayout &Layout) { |
| COFFSymbol *Sym = GetOrCreateCOFFSymbol(&MCSym); |
| const MCSymbol *Base = Layout.getBaseSymbol(MCSym); |
| COFFSection *Sec = nullptr; |
| if (Base && Base->getFragment()) { |
| Sec = SectionMap[Base->getFragment()->getParent()]; |
| if (Sym->Section && Sym->Section != Sec) |
| report_fatal_error("conflicting sections for symbol"); |
| } |
| |
| COFFSymbol *Local = nullptr; |
| if (cast<MCSymbolCOFF>(MCSym).isWeakExternal()) { |
| Sym->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL; |
| Sym->Section = nullptr; |
| |
| COFFSymbol *WeakDefault = getLinkedSymbol(MCSym); |
| if (!WeakDefault) { |
| std::string WeakName = (".weak." + MCSym.getName() + ".default").str(); |
| WeakDefault = createSymbol(WeakName); |
| if (!Sec) |
| WeakDefault->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE; |
| else |
| WeakDefault->Section = Sec; |
| WeakDefaults.insert(WeakDefault); |
| Local = WeakDefault; |
| } |
| |
| Sym->Other = WeakDefault; |
| |
| // Setup the Weak External auxiliary symbol. |
| Sym->Aux.resize(1); |
| memset(&Sym->Aux[0], 0, sizeof(Sym->Aux[0])); |
| Sym->Aux[0].AuxType = ATWeakExternal; |
| Sym->Aux[0].Aux.WeakExternal.TagIndex = 0; |
| Sym->Aux[0].Aux.WeakExternal.Characteristics = |
| COFF::IMAGE_WEAK_EXTERN_SEARCH_ALIAS; |
| } else { |
| if (!Base) |
| Sym->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE; |
| else |
| Sym->Section = Sec; |
| Local = Sym; |
| } |
| |
| if (Local) { |
| Local->Data.Value = getSymbolValue(MCSym, Layout); |
| |
| const MCSymbolCOFF &SymbolCOFF = cast<MCSymbolCOFF>(MCSym); |
| Local->Data.Type = SymbolCOFF.getType(); |
| Local->Data.StorageClass = SymbolCOFF.getClass(); |
| |
| // If no storage class was specified in the streamer, define it here. |
| if (Local->Data.StorageClass == COFF::IMAGE_SYM_CLASS_NULL) { |
| bool IsExternal = MCSym.isExternal() || |
| (!MCSym.getFragment() && !MCSym.isVariable()); |
| |
| Local->Data.StorageClass = IsExternal ? COFF::IMAGE_SYM_CLASS_EXTERNAL |
| : COFF::IMAGE_SYM_CLASS_STATIC; |
| } |
| } |
| |
| Sym->MC = &MCSym; |
| } |
| |
| void WinCOFFObjectWriter::SetSectionName(COFFSection &S) { |
| if (S.Name.size() <= COFF::NameSize) { |
| std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size()); |
| return; |
| } |
| |
| uint64_t StringTableEntry = Strings.getOffset(S.Name); |
| if (!COFF::encodeSectionName(S.Header.Name, StringTableEntry)) |
| report_fatal_error("COFF string table is greater than 64 GB."); |
| } |
| |
| void WinCOFFObjectWriter::SetSymbolName(COFFSymbol &S) { |
| if (S.Name.size() > COFF::NameSize) |
| S.set_name_offset(Strings.getOffset(S.Name)); |
| else |
| std::memcpy(S.Data.Name, S.Name.c_str(), S.Name.size()); |
| } |
| |
| bool WinCOFFObjectWriter::IsPhysicalSection(COFFSection *S) { |
| return (S->Header.Characteristics & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA) == |
| 0; |
| } |
| |
| //------------------------------------------------------------------------------ |
| // entity writing methods |
| |
| void WinCOFFObjectWriter::WriteFileHeader(const COFF::header &Header) { |
| if (UseBigObj) { |
| W.write<uint16_t>(COFF::IMAGE_FILE_MACHINE_UNKNOWN); |
| W.write<uint16_t>(0xFFFF); |
| W.write<uint16_t>(COFF::BigObjHeader::MinBigObjectVersion); |
| W.write<uint16_t>(Header.Machine); |
| W.write<uint32_t>(Header.TimeDateStamp); |
| W.OS.write(COFF::BigObjMagic, sizeof(COFF::BigObjMagic)); |
| W.write<uint32_t>(0); |
| W.write<uint32_t>(0); |
| W.write<uint32_t>(0); |
| W.write<uint32_t>(0); |
| W.write<uint32_t>(Header.NumberOfSections); |
| W.write<uint32_t>(Header.PointerToSymbolTable); |
| W.write<uint32_t>(Header.NumberOfSymbols); |
| } else { |
| W.write<uint16_t>(Header.Machine); |
| W.write<uint16_t>(static_cast<int16_t>(Header.NumberOfSections)); |
| W.write<uint32_t>(Header.TimeDateStamp); |
| W.write<uint32_t>(Header.PointerToSymbolTable); |
| W.write<uint32_t>(Header.NumberOfSymbols); |
| W.write<uint16_t>(Header.SizeOfOptionalHeader); |
| W.write<uint16_t>(Header.Characteristics); |
| } |
| } |
| |
| void WinCOFFObjectWriter::WriteSymbol(const COFFSymbol &S) { |
| W.OS.write(S.Data.Name, COFF::NameSize); |
| W.write<uint32_t>(S.Data.Value); |
| if (UseBigObj) |
| W.write<uint32_t>(S.Data.SectionNumber); |
| else |
| W.write<uint16_t>(static_cast<int16_t>(S.Data.SectionNumber)); |
| W.write<uint16_t>(S.Data.Type); |
| W.OS << char(S.Data.StorageClass); |
| W.OS << char(S.Data.NumberOfAuxSymbols); |
| WriteAuxiliarySymbols(S.Aux); |
| } |
| |
| void WinCOFFObjectWriter::WriteAuxiliarySymbols( |
| const COFFSymbol::AuxiliarySymbols &S) { |
| for (const AuxSymbol &i : S) { |
| switch (i.AuxType) { |
| case ATWeakExternal: |
| W.write<uint32_t>(i.Aux.WeakExternal.TagIndex); |
| W.write<uint32_t>(i.Aux.WeakExternal.Characteristics); |
| W.OS.write_zeros(sizeof(i.Aux.WeakExternal.unused)); |
| if (UseBigObj) |
| W.OS.write_zeros(COFF::Symbol32Size - COFF::Symbol16Size); |
| break; |
| case ATFile: |
| W.OS.write(reinterpret_cast<const char *>(&i.Aux), |
| UseBigObj ? COFF::Symbol32Size : COFF::Symbol16Size); |
| break; |
| case ATSectionDefinition: |
| W.write<uint32_t>(i.Aux.SectionDefinition.Length); |
| W.write<uint16_t>(i.Aux.SectionDefinition.NumberOfRelocations); |
| W.write<uint16_t>(i.Aux.SectionDefinition.NumberOfLinenumbers); |
| W.write<uint32_t>(i.Aux.SectionDefinition.CheckSum); |
| W.write<uint16_t>(static_cast<int16_t>(i.Aux.SectionDefinition.Number)); |
| W.OS << char(i.Aux.SectionDefinition.Selection); |
| W.OS.write_zeros(sizeof(i.Aux.SectionDefinition.unused)); |
| W.write<uint16_t>(static_cast<int16_t>(i.Aux.SectionDefinition.Number >> 16)); |
| if (UseBigObj) |
| W.OS.write_zeros(COFF::Symbol32Size - COFF::Symbol16Size); |
| break; |
| } |
| } |
| } |
| |
| // Write the section header. |
| void WinCOFFObjectWriter::writeSectionHeaders() { |
| // Section numbers must be monotonically increasing in the section |
| // header, but our Sections array is not sorted by section number, |
| // so make a copy of Sections and sort it. |
| std::vector<COFFSection *> Arr; |
| for (auto &Section : Sections) |
| Arr.push_back(Section.get()); |
| llvm::sort(Arr, [](const COFFSection *A, const COFFSection *B) { |
| return A->Number < B->Number; |
| }); |
| |
| for (auto &Section : Arr) { |
| if (Section->Number == -1) |
| continue; |
| |
| COFF::section &S = Section->Header; |
| if (Section->Relocations.size() >= 0xffff) |
| S.Characteristics |= COFF::IMAGE_SCN_LNK_NRELOC_OVFL; |
| W.OS.write(S.Name, COFF::NameSize); |
| W.write<uint32_t>(S.VirtualSize); |
| W.write<uint32_t>(S.VirtualAddress); |
| W.write<uint32_t>(S.SizeOfRawData); |
| W.write<uint32_t>(S.PointerToRawData); |
| W.write<uint32_t>(S.PointerToRelocations); |
| W.write<uint32_t>(S.PointerToLineNumbers); |
| W.write<uint16_t>(S.NumberOfRelocations); |
| W.write<uint16_t>(S.NumberOfLineNumbers); |
| W.write<uint32_t>(S.Characteristics); |
| } |
| } |
| |
| void WinCOFFObjectWriter::WriteRelocation(const COFF::relocation &R) { |
| W.write<uint32_t>(R.VirtualAddress); |
| W.write<uint32_t>(R.SymbolTableIndex); |
| W.write<uint16_t>(R.Type); |
| } |
| |
| // Write MCSec's contents. What this function does is essentially |
| // "Asm.writeSectionData(&MCSec, Layout)", but it's a bit complicated |
| // because it needs to compute a CRC. |
| uint32_t WinCOFFObjectWriter::writeSectionContents(MCAssembler &Asm, |
| const MCAsmLayout &Layout, |
| const MCSection &MCSec) { |
| // Save the contents of the section to a temporary buffer, we need this |
| // to CRC the data before we dump it into the object file. |
| SmallVector<char, 128> Buf; |
| raw_svector_ostream VecOS(Buf); |
| Asm.writeSectionData(VecOS, &MCSec, Layout); |
| |
| // Write the section contents to the object file. |
| W.OS << Buf; |
| |
| // Calculate our CRC with an initial value of '0', this is not how |
| // JamCRC is specified but it aligns with the expected output. |
| JamCRC JC(/*Init=*/0); |
| JC.update(ArrayRef(reinterpret_cast<uint8_t *>(Buf.data()), Buf.size())); |
| return JC.getCRC(); |
| } |
| |
| void WinCOFFObjectWriter::writeSection(MCAssembler &Asm, |
| const MCAsmLayout &Layout, |
| const COFFSection &Sec) { |
| if (Sec.Number == -1) |
| return; |
| |
| // Write the section contents. |
| if (Sec.Header.PointerToRawData != 0) { |
| assert(W.OS.tell() == Sec.Header.PointerToRawData && |
| "Section::PointerToRawData is insane!"); |
| |
| uint32_t CRC = writeSectionContents(Asm, Layout, *Sec.MCSection); |
| |
| // Update the section definition auxiliary symbol to record the CRC. |
| COFFSymbol::AuxiliarySymbols &AuxSyms = Sec.Symbol->Aux; |
| assert(AuxSyms.size() == 1 && AuxSyms[0].AuxType == ATSectionDefinition); |
| AuxSymbol &SecDef = AuxSyms[0]; |
| SecDef.Aux.SectionDefinition.CheckSum = CRC; |
| } |
| |
| // Write relocations for this section. |
| if (Sec.Relocations.empty()) { |
| assert(Sec.Header.PointerToRelocations == 0 && |
| "Section::PointerToRelocations is insane!"); |
| return; |
| } |
| |
| assert(W.OS.tell() == Sec.Header.PointerToRelocations && |
| "Section::PointerToRelocations is insane!"); |
| |
| if (Sec.Relocations.size() >= 0xffff) { |
| // In case of overflow, write actual relocation count as first |
| // relocation. Including the synthetic reloc itself (+ 1). |
| COFF::relocation R; |
| R.VirtualAddress = Sec.Relocations.size() + 1; |
| R.SymbolTableIndex = 0; |
| R.Type = 0; |
| WriteRelocation(R); |
| } |
| |
| for (const auto &Relocation : Sec.Relocations) |
| WriteRelocation(Relocation.Data); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // MCObjectWriter interface implementations |
| |
| void WinCOFFObjectWriter::executePostLayoutBinding(MCAssembler &Asm, |
| const MCAsmLayout &Layout) { |
| if (EmitAddrsigSection) { |
| AddrsigSection = Asm.getContext().getCOFFSection( |
| ".llvm_addrsig", COFF::IMAGE_SCN_LNK_REMOVE, |
| SectionKind::getMetadata()); |
| Asm.registerSection(*AddrsigSection); |
| } |
| |
| if (!Asm.CGProfile.empty()) { |
| CGProfileSection = Asm.getContext().getCOFFSection( |
| ".llvm.call-graph-profile", COFF::IMAGE_SCN_LNK_REMOVE, |
| SectionKind::getMetadata()); |
| Asm.registerSection(*CGProfileSection); |
| } |
| |
| // "Define" each section & symbol. This creates section & symbol |
| // entries in the staging area. |
| for (const auto &Section : Asm) |
| defineSection(static_cast<const MCSectionCOFF &>(Section), Layout); |
| |
| for (const MCSymbol &Symbol : Asm.symbols()) |
| if (!Symbol.isTemporary()) |
| DefineSymbol(Symbol, Asm, Layout); |
| } |
| |
| bool WinCOFFObjectWriter::isSymbolRefDifferenceFullyResolvedImpl( |
| const MCAssembler &Asm, const MCSymbol &SymA, const MCFragment &FB, |
| bool InSet, bool IsPCRel) const { |
| // Don't drop relocations between functions, even if they are in the same text |
| // section. Multiple Visual C++ linker features depend on having the |
| // relocations present. The /INCREMENTAL flag will cause these relocations to |
| // point to thunks, and the /GUARD:CF flag assumes that it can use relocations |
| // to approximate the set of all address taken functions. LLD's implementation |
| // of /GUARD:CF also relies on the existance of these relocations. |
| uint16_t Type = cast<MCSymbolCOFF>(SymA).getType(); |
| if ((Type >> COFF::SCT_COMPLEX_TYPE_SHIFT) == COFF::IMAGE_SYM_DTYPE_FUNCTION) |
| return false; |
| return MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(Asm, SymA, FB, |
| InSet, IsPCRel); |
| } |
| |
| void WinCOFFObjectWriter::recordRelocation(MCAssembler &Asm, |
| const MCAsmLayout &Layout, |
| const MCFragment *Fragment, |
| const MCFixup &Fixup, MCValue Target, |
| uint64_t &FixedValue) { |
| assert(Target.getSymA() && "Relocation must reference a symbol!"); |
| |
| const MCSymbol &A = Target.getSymA()->getSymbol(); |
| if (!A.isRegistered()) { |
| Asm.getContext().reportError(Fixup.getLoc(), |
| Twine("symbol '") + A.getName() + |
| "' can not be undefined"); |
| return; |
| } |
| if (A.isTemporary() && A.isUndefined()) { |
| Asm.getContext().reportError(Fixup.getLoc(), |
| Twine("assembler label '") + A.getName() + |
| "' can not be undefined"); |
| return; |
| } |
| |
| MCSection *MCSec = Fragment->getParent(); |
| |
| // Mark this symbol as requiring an entry in the symbol table. |
| assert(SectionMap.contains(MCSec) && |
| "Section must already have been defined in executePostLayoutBinding!"); |
| |
| COFFSection *Sec = SectionMap[MCSec]; |
| const MCSymbolRefExpr *SymB = Target.getSymB(); |
| |
| if (SymB) { |
| const MCSymbol *B = &SymB->getSymbol(); |
| if (!B->getFragment()) { |
| Asm.getContext().reportError( |
| Fixup.getLoc(), |
| Twine("symbol '") + B->getName() + |
| "' can not be undefined in a subtraction expression"); |
| return; |
| } |
| |
| // Offset of the symbol in the section |
| int64_t OffsetOfB = Layout.getSymbolOffset(*B); |
| |
| // Offset of the relocation in the section |
| int64_t OffsetOfRelocation = |
| Layout.getFragmentOffset(Fragment) + Fixup.getOffset(); |
| |
| FixedValue = (OffsetOfRelocation - OffsetOfB) + Target.getConstant(); |
| } else { |
| FixedValue = Target.getConstant(); |
| } |
| |
| COFFRelocation Reloc; |
| |
| Reloc.Data.SymbolTableIndex = 0; |
| Reloc.Data.VirtualAddress = Layout.getFragmentOffset(Fragment); |
| |
| // Turn relocations for temporary symbols into section relocations. |
| if (A.isTemporary()) { |
| MCSection *TargetSection = &A.getSection(); |
| assert( |
| SectionMap.contains(TargetSection) && |
| "Section must already have been defined in executePostLayoutBinding!"); |
| COFFSection *Section = SectionMap[TargetSection]; |
| Reloc.Symb = Section->Symbol; |
| FixedValue += Layout.getSymbolOffset(A); |
| // Technically, we should do the final adjustments of FixedValue (below) |
| // before picking an offset symbol, otherwise we might choose one which |
| // is slightly too far away. The relocations where it really matters |
| // (arm64 adrp relocations) don't get any offset though. |
| if (UseOffsetLabels && !Section->OffsetSymbols.empty()) { |
| uint64_t LabelIndex = FixedValue >> OffsetLabelIntervalBits; |
| if (LabelIndex > 0) { |
| if (LabelIndex <= Section->OffsetSymbols.size()) |
| Reloc.Symb = Section->OffsetSymbols[LabelIndex - 1]; |
| else |
| Reloc.Symb = Section->OffsetSymbols.back(); |
| FixedValue -= Reloc.Symb->Data.Value; |
| } |
| } |
| } else { |
| assert( |
| SymbolMap.contains(&A) && |
| "Symbol must already have been defined in executePostLayoutBinding!"); |
| Reloc.Symb = SymbolMap[&A]; |
| } |
| |
| ++Reloc.Symb->Relocations; |
| |
| Reloc.Data.VirtualAddress += Fixup.getOffset(); |
| Reloc.Data.Type = TargetObjectWriter->getRelocType( |
| Asm.getContext(), Target, Fixup, SymB, Asm.getBackend()); |
| |
| // The *_REL32 relocations are relative to the end of the relocation, |
| // not to the start. |
| if ((Header.Machine == COFF::IMAGE_FILE_MACHINE_AMD64 && |
| Reloc.Data.Type == COFF::IMAGE_REL_AMD64_REL32) || |
| (Header.Machine == COFF::IMAGE_FILE_MACHINE_I386 && |
| Reloc.Data.Type == COFF::IMAGE_REL_I386_REL32) || |
| (Header.Machine == COFF::IMAGE_FILE_MACHINE_ARMNT && |
| Reloc.Data.Type == COFF::IMAGE_REL_ARM_REL32) || |
| (Header.Machine == COFF::IMAGE_FILE_MACHINE_ARM64 && |
| Reloc.Data.Type == COFF::IMAGE_REL_ARM64_REL32)) |
| FixedValue += 4; |
| |
| if (Header.Machine == COFF::IMAGE_FILE_MACHINE_ARMNT) { |
| switch (Reloc.Data.Type) { |
| case COFF::IMAGE_REL_ARM_ABSOLUTE: |
| case COFF::IMAGE_REL_ARM_ADDR32: |
| case COFF::IMAGE_REL_ARM_ADDR32NB: |
| case COFF::IMAGE_REL_ARM_TOKEN: |
| case COFF::IMAGE_REL_ARM_SECTION: |
| case COFF::IMAGE_REL_ARM_SECREL: |
| break; |
| case COFF::IMAGE_REL_ARM_BRANCH11: |
| case COFF::IMAGE_REL_ARM_BLX11: |
| // IMAGE_REL_ARM_BRANCH11 and IMAGE_REL_ARM_BLX11 are only used for |
| // pre-ARMv7, which implicitly rules it out of ARMNT (it would be valid |
| // for Windows CE). |
| case COFF::IMAGE_REL_ARM_BRANCH24: |
| case COFF::IMAGE_REL_ARM_BLX24: |
| case COFF::IMAGE_REL_ARM_MOV32A: |
| // IMAGE_REL_ARM_BRANCH24, IMAGE_REL_ARM_BLX24, IMAGE_REL_ARM_MOV32A are |
| // only used for ARM mode code, which is documented as being unsupported |
| // by Windows on ARM. Empirical proof indicates that masm is able to |
| // generate the relocations however the rest of the MSVC toolchain is |
| // unable to handle it. |
| llvm_unreachable("unsupported relocation"); |
| break; |
| case COFF::IMAGE_REL_ARM_MOV32T: |
| break; |
| case COFF::IMAGE_REL_ARM_BRANCH20T: |
| case COFF::IMAGE_REL_ARM_BRANCH24T: |
| case COFF::IMAGE_REL_ARM_BLX23T: |
| // IMAGE_REL_BRANCH20T, IMAGE_REL_ARM_BRANCH24T, IMAGE_REL_ARM_BLX23T all |
| // perform a 4 byte adjustment to the relocation. Relative branches are |
| // offset by 4 on ARM, however, because there is no RELA relocations, all |
| // branches are offset by 4. |
| FixedValue = FixedValue + 4; |
| break; |
| } |
| } |
| |
| // The fixed value never makes sense for section indices, ignore it. |
| if (Fixup.getKind() == FK_SecRel_2) |
| FixedValue = 0; |
| |
| if (TargetObjectWriter->recordRelocation(Fixup)) |
| Sec->Relocations.push_back(Reloc); |
| } |
| |
| static std::time_t getTime() { |
| std::time_t Now = time(nullptr); |
| if (Now < 0 || !isUInt<32>(Now)) |
| return UINT32_MAX; |
| return Now; |
| } |
| |
| // Create .file symbols. |
| void WinCOFFObjectWriter::createFileSymbols(MCAssembler &Asm) { |
| for (const std::pair<std::string, size_t> &It : Asm.getFileNames()) { |
| // round up to calculate the number of auxiliary symbols required |
| const std::string &Name = It.first; |
| unsigned SymbolSize = UseBigObj ? COFF::Symbol32Size : COFF::Symbol16Size; |
| unsigned Count = (Name.size() + SymbolSize - 1) / SymbolSize; |
| |
| COFFSymbol *File = createSymbol(".file"); |
| File->Data.SectionNumber = COFF::IMAGE_SYM_DEBUG; |
| File->Data.StorageClass = COFF::IMAGE_SYM_CLASS_FILE; |
| File->Aux.resize(Count); |
| |
| unsigned Offset = 0; |
| unsigned Length = Name.size(); |
| for (auto &Aux : File->Aux) { |
| Aux.AuxType = ATFile; |
| |
| if (Length > SymbolSize) { |
| memcpy(&Aux.Aux, Name.c_str() + Offset, SymbolSize); |
| Length = Length - SymbolSize; |
| } else { |
| memcpy(&Aux.Aux, Name.c_str() + Offset, Length); |
| memset((char *)&Aux.Aux + Length, 0, SymbolSize - Length); |
| break; |
| } |
| |
| Offset += SymbolSize; |
| } |
| } |
| } |
| |
| void WinCOFFObjectWriter::setWeakDefaultNames() { |
| if (WeakDefaults.empty()) |
| return; |
| |
| // If multiple object files use a weak symbol (either with a regular |
| // defined default, or an absolute zero symbol as default), the defaults |
| // cause duplicate definitions unless their names are made unique. Look |
| // for a defined extern symbol, that isn't comdat - that should be unique |
| // unless there are other duplicate definitions. And if none is found, |
| // allow picking a comdat symbol, as that's still better than nothing. |
| |
| COFFSymbol *Unique = nullptr; |
| for (bool AllowComdat : {false, true}) { |
| for (auto &Sym : Symbols) { |
| // Don't include the names of the defaults themselves |
| if (WeakDefaults.count(Sym.get())) |
| continue; |
| // Only consider external symbols |
| if (Sym->Data.StorageClass != COFF::IMAGE_SYM_CLASS_EXTERNAL) |
| continue; |
| // Only consider symbols defined in a section or that are absolute |
| if (!Sym->Section && Sym->Data.SectionNumber != COFF::IMAGE_SYM_ABSOLUTE) |
| continue; |
| if (!AllowComdat && Sym->Section && |
| Sym->Section->Header.Characteristics & COFF::IMAGE_SCN_LNK_COMDAT) |
| continue; |
| Unique = Sym.get(); |
| break; |
| } |
| if (Unique) |
| break; |
| } |
| // If we didn't find any unique symbol to use for the names, just skip this. |
| if (!Unique) |
| return; |
| for (auto *Sym : WeakDefaults) { |
| Sym->Name.append("."); |
| Sym->Name.append(Unique->Name); |
| } |
| } |
| |
| static bool isAssociative(const COFFSection &Section) { |
| return Section.Symbol->Aux[0].Aux.SectionDefinition.Selection == |
| COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE; |
| } |
| |
| void WinCOFFObjectWriter::assignSectionNumbers() { |
| size_t I = 1; |
| auto Assign = [&](COFFSection &Section) { |
| Section.Number = I; |
| Section.Symbol->Data.SectionNumber = I; |
| Section.Symbol->Aux[0].Aux.SectionDefinition.Number = I; |
| ++I; |
| }; |
| |
| // Although it is not explicitly requested by the Microsoft COFF spec, |
| // we should avoid emitting forward associative section references, |
| // because MSVC link.exe as of 2017 cannot handle that. |
| for (const std::unique_ptr<COFFSection> &Section : Sections) |
| if (!isAssociative(*Section)) |
| Assign(*Section); |
| for (const std::unique_ptr<COFFSection> &Section : Sections) |
| if (isAssociative(*Section)) |
| Assign(*Section); |
| } |
| |
| // Assign file offsets to COFF object file structures. |
| void WinCOFFObjectWriter::assignFileOffsets(MCAssembler &Asm, |
| const MCAsmLayout &Layout) { |
| unsigned Offset = W.OS.tell(); |
| |
| Offset += UseBigObj ? COFF::Header32Size : COFF::Header16Size; |
| Offset += COFF::SectionSize * Header.NumberOfSections; |
| |
| for (const auto &Section : Asm) { |
| COFFSection *Sec = SectionMap[&Section]; |
| |
| if (!Sec || Sec->Number == -1) |
| continue; |
| |
| Sec->Header.SizeOfRawData = Layout.getSectionAddressSize(&Section); |
| |
| if (IsPhysicalSection(Sec)) { |
| Sec->Header.PointerToRawData = Offset; |
| Offset += Sec->Header.SizeOfRawData; |
| } |
| |
| if (!Sec->Relocations.empty()) { |
| bool RelocationsOverflow = Sec->Relocations.size() >= 0xffff; |
| |
| if (RelocationsOverflow) { |
| // Signal overflow by setting NumberOfRelocations to max value. Actual |
| // size is found in reloc #0. Microsoft tools understand this. |
| Sec->Header.NumberOfRelocations = 0xffff; |
| } else { |
| Sec->Header.NumberOfRelocations = Sec->Relocations.size(); |
| } |
| Sec->Header.PointerToRelocations = Offset; |
| |
| if (RelocationsOverflow) { |
| // Reloc #0 will contain actual count, so make room for it. |
| Offset += COFF::RelocationSize; |
| } |
| |
| Offset += COFF::RelocationSize * Sec->Relocations.size(); |
| |
| for (auto &Relocation : Sec->Relocations) { |
| assert(Relocation.Symb->getIndex() != -1); |
| Relocation.Data.SymbolTableIndex = Relocation.Symb->getIndex(); |
| } |
| } |
| |
| assert(Sec->Symbol->Aux.size() == 1 && |
| "Section's symbol must have one aux!"); |
| AuxSymbol &Aux = Sec->Symbol->Aux[0]; |
| assert(Aux.AuxType == ATSectionDefinition && |
| "Section's symbol's aux symbol must be a Section Definition!"); |
| Aux.Aux.SectionDefinition.Length = Sec->Header.SizeOfRawData; |
| Aux.Aux.SectionDefinition.NumberOfRelocations = |
| Sec->Header.NumberOfRelocations; |
| Aux.Aux.SectionDefinition.NumberOfLinenumbers = |
| Sec->Header.NumberOfLineNumbers; |
| } |
| |
| Header.PointerToSymbolTable = Offset; |
| } |
| |
| uint64_t WinCOFFObjectWriter::writeObject(MCAssembler &Asm, |
| const MCAsmLayout &Layout) { |
| uint64_t StartOffset = W.OS.tell(); |
| |
| if (Sections.size() > INT32_MAX) |
| report_fatal_error( |
| "PE COFF object files can't have more than 2147483647 sections"); |
| |
| UseBigObj = Sections.size() > COFF::MaxNumberOfSections16; |
| Header.NumberOfSections = Sections.size(); |
| Header.NumberOfSymbols = 0; |
| |
| setWeakDefaultNames(); |
| assignSectionNumbers(); |
| createFileSymbols(Asm); |
| |
| for (auto &Symbol : Symbols) { |
| // Update section number & offset for symbols that have them. |
| if (Symbol->Section) |
| Symbol->Data.SectionNumber = Symbol->Section->Number; |
| Symbol->setIndex(Header.NumberOfSymbols++); |
| // Update auxiliary symbol info. |
| Symbol->Data.NumberOfAuxSymbols = Symbol->Aux.size(); |
| Header.NumberOfSymbols += Symbol->Data.NumberOfAuxSymbols; |
| } |
| |
| // Build string table. |
| for (const auto &S : Sections) |
| if (S->Name.size() > COFF::NameSize) |
| Strings.add(S->Name); |
| for (const auto &S : Symbols) |
| if (S->Name.size() > COFF::NameSize) |
| Strings.add(S->Name); |
| Strings.finalize(); |
| |
| // Set names. |
| for (const auto &S : Sections) |
| SetSectionName(*S); |
| for (auto &S : Symbols) |
| SetSymbolName(*S); |
| |
| // Fixup weak external references. |
| for (auto &Symbol : Symbols) { |
| if (Symbol->Other) { |
| assert(Symbol->getIndex() != -1); |
| assert(Symbol->Aux.size() == 1 && "Symbol must contain one aux symbol!"); |
| assert(Symbol->Aux[0].AuxType == ATWeakExternal && |
| "Symbol's aux symbol must be a Weak External!"); |
| Symbol->Aux[0].Aux.WeakExternal.TagIndex = Symbol->Other->getIndex(); |
| } |
| } |
| |
| // Fixup associative COMDAT sections. |
| for (auto &Section : Sections) { |
| if (Section->Symbol->Aux[0].Aux.SectionDefinition.Selection != |
| COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) |
| continue; |
| |
| const MCSectionCOFF &MCSec = *Section->MCSection; |
| const MCSymbol *AssocMCSym = MCSec.getCOMDATSymbol(); |
| assert(AssocMCSym); |
| |
| // It's an error to try to associate with an undefined symbol or a symbol |
| // without a section. |
| if (!AssocMCSym->isInSection()) { |
| Asm.getContext().reportError( |
| SMLoc(), Twine("cannot make section ") + MCSec.getName() + |
| Twine(" associative with sectionless symbol ") + |
| AssocMCSym->getName()); |
| continue; |
| } |
| |
| const auto *AssocMCSec = cast<MCSectionCOFF>(&AssocMCSym->getSection()); |
| assert(SectionMap.count(AssocMCSec)); |
| COFFSection *AssocSec = SectionMap[AssocMCSec]; |
| |
| // Skip this section if the associated section is unused. |
| if (AssocSec->Number == -1) |
| continue; |
| |
| Section->Symbol->Aux[0].Aux.SectionDefinition.Number = AssocSec->Number; |
| } |
| |
| // Create the contents of the .llvm_addrsig section. |
| if (EmitAddrsigSection) { |
| auto Frag = new MCDataFragment(AddrsigSection); |
| Frag->setLayoutOrder(0); |
| raw_svector_ostream OS(Frag->getContents()); |
| for (const MCSymbol *S : AddrsigSyms) { |
| if (!S->isRegistered()) |
| continue; |
| if (!S->isTemporary()) { |
| encodeULEB128(S->getIndex(), OS); |
| continue; |
| } |
| |
| MCSection *TargetSection = &S->getSection(); |
| assert(SectionMap.contains(TargetSection) && |
| "Section must already have been defined in " |
| "executePostLayoutBinding!"); |
| encodeULEB128(SectionMap[TargetSection]->Symbol->getIndex(), OS); |
| } |
| } |
| |
| // Create the contents of the .llvm.call-graph-profile section. |
| if (CGProfileSection) { |
| auto *Frag = new MCDataFragment(CGProfileSection); |
| Frag->setLayoutOrder(0); |
| raw_svector_ostream OS(Frag->getContents()); |
| for (const MCAssembler::CGProfileEntry &CGPE : Asm.CGProfile) { |
| uint32_t FromIndex = CGPE.From->getSymbol().getIndex(); |
| uint32_t ToIndex = CGPE.To->getSymbol().getIndex(); |
| support::endian::write(OS, FromIndex, W.Endian); |
| support::endian::write(OS, ToIndex, W.Endian); |
| support::endian::write(OS, CGPE.Count, W.Endian); |
| } |
| } |
| |
| assignFileOffsets(Asm, Layout); |
| |
| // MS LINK expects to be able to use this timestamp to implement their |
| // /INCREMENTAL feature. |
| if (Asm.isIncrementalLinkerCompatible()) { |
| Header.TimeDateStamp = getTime(); |
| } else { |
| // Have deterministic output if /INCREMENTAL isn't needed. Also matches GNU. |
| Header.TimeDateStamp = 0; |
| } |
| |
| // Write it all to disk... |
| WriteFileHeader(Header); |
| writeSectionHeaders(); |
| |
| #ifndef NDEBUG |
| sections::iterator I = Sections.begin(); |
| sections::iterator IE = Sections.end(); |
| MCAssembler::iterator J = Asm.begin(); |
| MCAssembler::iterator JE = Asm.end(); |
| for (; I != IE && J != JE; ++I, ++J) |
| assert((**I).MCSection == &*J && "Wrong bound MCSection"); |
| #endif |
| |
| // Write section contents. |
| for (std::unique_ptr<COFFSection> &Sec : Sections) |
| writeSection(Asm, Layout, *Sec); |
| |
| assert(W.OS.tell() == Header.PointerToSymbolTable && |
| "Header::PointerToSymbolTable is insane!"); |
| |
| // Write a symbol table. |
| for (auto &Symbol : Symbols) |
| if (Symbol->getIndex() != -1) |
| WriteSymbol(*Symbol); |
| |
| // Write a string table, which completes the entire COFF file. |
| Strings.write(W.OS); |
| |
| return W.OS.tell() - StartOffset; |
| } |
| |
| MCWinCOFFObjectTargetWriter::MCWinCOFFObjectTargetWriter(unsigned Machine_) |
| : Machine(Machine_) {} |
| |
| // Pin the vtable to this file. |
| void MCWinCOFFObjectTargetWriter::anchor() {} |
| |
| //------------------------------------------------------------------------------ |
| // WinCOFFObjectWriter factory function |
| |
| std::unique_ptr<MCObjectWriter> llvm::createWinCOFFObjectWriter( |
| std::unique_ptr<MCWinCOFFObjectTargetWriter> MOTW, raw_pwrite_stream &OS) { |
| return std::make_unique<WinCOFFObjectWriter>(std::move(MOTW), OS); |
| } |