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diff --git a/llvm/lib/MC/WinCOFFObjectWriter.cpp b/llvm/lib/MC/WinCOFFObjectWriter.cpp
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+++ b/llvm/lib/MC/WinCOFFObjectWriter.cpp
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+//===- 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/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/Endian.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 <cstddef>
+#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 {
+
+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;
+ 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;
+ MCSectionCOFF const *MCSection = nullptr;
+ COFFSymbol *Symbol = nullptr;
+ relocations Relocations;
+
+ COFFSection(StringRef Name) : Name(Name) {}
+};
+
+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 *>;
+
+ 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;
+
+ bool UseBigObj;
+
+ bool EmitAddrsigSection = false;
+ MCSectionCOFF *AddrsigSection;
+ std::vector<const MCSymbol *> AddrsigSyms;
+
+ 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();
+ MCObjectWriter::reset();
+ }
+
+ COFFSymbol *createSymbol(StringRef Name);
+ COFFSymbol *GetOrCreateCOFFSymbol(const MCSymbol *Symbol);
+ COFFSection *createSection(StringRef Name);
+
+ void defineSection(MCSectionCOFF const &Sec);
+
+ 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, const MCSection &MCSec);
+
+ // 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 assignSectionNumbers();
+ void assignFileOffsets(MCAssembler &Asm, const MCAsmLayout &Layout);
+
+ void emitAddrsigSection() override { EmitAddrsigSection = true; }
+ void addAddrsigSymbol(const MCSymbol *Sym) override {
+ AddrsigSyms.push_back(Sym);
+ }
+
+ 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();
+}
+
+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.getAlignment()) {
+ 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) {
+ COFFSection *Section = createSection(MCSec.getSectionName());
+ COFFSymbol *Symbol = createSymbol(MCSec.getSectionName());
+ 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;
+}
+
+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())
+ return nullptr;
+ return GetOrCreateCOFFSymbol(&Aliasee);
+}
+
+/// 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;
+
+ 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;
+ 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;
+}
+
+// Maximum offsets for different string table entry encodings.
+enum : unsigned { Max7DecimalOffset = 9999999U };
+enum : uint64_t { MaxBase64Offset = 0xFFFFFFFFFULL }; // 64^6, including 0
+
+// Encode a string table entry offset in base 64, padded to 6 chars, and
+// prefixed with a double slash: '//AAAAAA', '//AAAAAB', ...
+// Buffer must be at least 8 bytes large. No terminating null appended.
+static void encodeBase64StringEntry(char *Buffer, uint64_t Value) {
+ assert(Value > Max7DecimalOffset && Value <= MaxBase64Offset &&
+ "Illegal section name encoding for value");
+
+ static const char Alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ "abcdefghijklmnopqrstuvwxyz"
+ "0123456789+/";
+
+ Buffer[0] = '/';
+ Buffer[1] = '/';
+
+ char *Ptr = Buffer + 7;
+ for (unsigned i = 0; i < 6; ++i) {
+ unsigned Rem = Value % 64;
+ Value /= 64;
+ *(Ptr--) = Alphabet[Rem];
+ }
+}
+
+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 (StringTableEntry <= Max7DecimalOffset) {
+ SmallVector<char, COFF::NameSize> Buffer;
+ Twine('/').concat(Twine(StringTableEntry)).toVector(Buffer);
+ assert(Buffer.size() <= COFF::NameSize && Buffer.size() >= 2);
+ std::memcpy(S.Header.Name, Buffer.data(), Buffer.size());
+ return;
+ }
+ if (StringTableEntry <= MaxBase64Offset) {
+ // Starting with 10,000,000, offsets are encoded as base64.
+ encodeBase64StringEntry(S.Header.Name, StringTableEntry);
+ return;
+ }
+ 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(makeArrayRef(reinterpret_cast<uint8_t*>(Buf.data()), Buf.size()));
+ return JC.getCRC();
+}
+
+void WinCOFFObjectWriter::writeSection(MCAssembler &Asm,
+ const MCAsmLayout &Layout,
+ const COFFSection &Sec,
+ const MCSection &MCSec) {
+ 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, MCSec);
+
+ // Update the section definition auxiliary symbol to record the CRC.
+ COFFSection *Sec = SectionMap[&MCSec];
+ 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);
+ }
+
+ // "Define" each section & symbol. This creates section & symbol
+ // entries in the staging area.
+ for (const auto &Section : Asm)
+ defineSection(static_cast<const MCSectionCOFF &>(Section));
+
+ 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.find(MCSec) != SectionMap.end() &&
+ "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.find(TargetSection) != SectionMap.end() &&
+ "Section must already have been defined in executePostLayoutBinding!");
+ Reloc.Symb = SectionMap[TargetSection]->Symbol;
+ FixedValue += Layout.getSymbolOffset(A);
+ } else {
+ assert(
+ SymbolMap.find(&A) != SymbolMap.end() &&
+ "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());
+
+ // FIXME: Can anyone explain what this does other than adjust for the size
+ // of the offset?
+ 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))
+ 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::string &Name : Asm.getFileNames()) {
+ // round up to calculate the number of auxiliary symbols required
+ 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;
+ }
+ }
+}
+
+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->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;
+
+ 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.getSectionName() +
+ 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->isTemporary()) {
+ encodeULEB128(S->getIndex(), OS);
+ continue;
+ }
+
+ MCSection *TargetSection = &S->getSection();
+ assert(SectionMap.find(TargetSection) != SectionMap.end() &&
+ "Section must already have been defined in "
+ "executePostLayoutBinding!");
+ encodeULEB128(SectionMap[TargetSection]->Symbol->getIndex(), OS);
+ }
+ }
+
+ 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();
+
+ // Write section contents.
+ 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)
+ writeSection(Asm, Layout, **I, *J);
+
+ 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);
+}
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