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//===-- llvm/MC/WinCOFFStreamer.cpp -----------------------------*- C++ -*-===//
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// The LLVM Compiler Infrastructure
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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// This file contains an implementation of a Win32 COFF object file streamer.
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "WinCOFFStreamer"
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#include "llvm/MC/MCObjectStreamer.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCSection.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCAsmLayout.h"
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#include "llvm/MC/MCCodeEmitter.h"
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#include "llvm/MC/MCSectionCOFF.h"
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#include "llvm/Target/TargetRegistry.h"
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#include "llvm/Target/TargetAsmBackend.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/Support/COFF.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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class WinCOFFStreamer : public MCObjectStreamer {
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MCSymbol const *CurSymbol;
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WinCOFFStreamer(MCContext &Context,
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TargetAsmBackend &TAB,
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void AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
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unsigned ByteAlignment, bool External);
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// MCStreamer interface
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virtual void EmitLabel(MCSymbol *Symbol);
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virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
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virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
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virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
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virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
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virtual void BeginCOFFSymbolDef(MCSymbol const *Symbol);
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virtual void EmitCOFFSymbolStorageClass(int StorageClass);
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virtual void EmitCOFFSymbolType(int Type);
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virtual void EndCOFFSymbolDef();
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virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value);
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virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
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unsigned ByteAlignment);
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virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size);
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virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
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unsigned Size,unsigned ByteAlignment);
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virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
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uint64_t Size, unsigned ByteAlignment);
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virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
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virtual void EmitValue(const MCExpr *Value, unsigned Size,
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virtual void EmitGPRel32Value(const MCExpr *Value);
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virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
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unsigned ValueSize, unsigned MaxBytesToEmit);
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virtual void EmitCodeAlignment(unsigned ByteAlignment,
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unsigned MaxBytesToEmit);
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virtual void EmitValueToOffset(const MCExpr *Offset, unsigned char Value);
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virtual void EmitFileDirective(StringRef Filename);
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virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename);
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virtual void EmitInstruction(const MCInst &Instruction);
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virtual void Finish();
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} // end anonymous namespace.
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WinCOFFStreamer::WinCOFFStreamer(MCContext &Context,
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TargetAsmBackend &TAB,
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: MCObjectStreamer(Context, TAB, OS, &CE)
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void WinCOFFStreamer::AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
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unsigned ByteAlignment, bool External) {
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assert(!Symbol->isInSection() && "Symbol must not already have a section!");
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std::string SectionName(".bss$linkonce");
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SectionName.append(Symbol->getName().begin(), Symbol->getName().end());
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MCSymbolData &SymbolData = getAssembler().getOrCreateSymbolData(*Symbol);
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unsigned Characteristics =
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COFF::IMAGE_SCN_LNK_COMDAT |
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COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
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COFF::IMAGE_SCN_MEM_READ |
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COFF::IMAGE_SCN_MEM_WRITE;
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int Selection = COFF::IMAGE_COMDAT_SELECT_LARGEST;
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const MCSection *Section = MCStreamer::getContext().getCOFFSection(
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SectionName, Characteristics, Selection, SectionKind::getBSS());
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MCSectionData &SectionData = getAssembler().getOrCreateSectionData(*Section);
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if (SectionData.getAlignment() < ByteAlignment)
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SectionData.setAlignment(ByteAlignment);
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SymbolData.setExternal(External);
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Symbol->setSection(*Section);
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if (ByteAlignment != 1)
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new MCAlignFragment(ByteAlignment, 0, 0, ByteAlignment, &SectionData);
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SymbolData.setFragment(new MCFillFragment(0, 0, Size, &SectionData));
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// MCStreamer interface
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void WinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
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// TODO: This is copied almost exactly from the MachOStreamer. Consider
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// merging into MCObjectStreamer?
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assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
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assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
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assert(CurSection && "Cannot emit before setting section!");
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Symbol->setSection(*CurSection);
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MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
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// FIXME: This is wasteful, we don't necessarily need to create a data
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// fragment. Instead, we should mark the symbol as pointing into the data
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// fragment if it exists, otherwise we should just queue the label and set its
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// fragment pointer when we emit the next fragment.
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MCDataFragment *DF = getOrCreateDataFragment();
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assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
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SD.setOffset(DF->getContents().size());
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void WinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
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llvm_unreachable("not implemented");
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void WinCOFFStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
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// TODO: This is exactly the same as MachOStreamer. Consider merging into
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getAssembler().getOrCreateSymbolData(*Symbol);
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AddValueSymbols(Value);
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Symbol->setVariableValue(Value);
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void WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
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MCSymbolAttr Attribute) {
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case MCSA_WeakReference:
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getAssembler().getOrCreateSymbolData(*Symbol).modifyFlags(
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COFF::SF_WeakReference,
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COFF::SF_WeakReference);
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getAssembler().getOrCreateSymbolData(*Symbol).setExternal(true);
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llvm_unreachable("unsupported attribute");
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void WinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
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llvm_unreachable("not implemented");
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void WinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
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assert(CurSymbol == NULL && "EndCOFFSymbolDef must be called between calls "
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"to BeginCOFFSymbolDef!");
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void WinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
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assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
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assert((StorageClass & ~0xFF) == 0 && "StorageClass must only have data in "
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getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
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StorageClass << COFF::SF_ClassShift,
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void WinCOFFStreamer::EmitCOFFSymbolType(int Type) {
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assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
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assert((Type & ~0xFFFF) == 0 && "Type must only have data in the first 2 "
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getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
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Type << COFF::SF_TypeShift,
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void WinCOFFStreamer::EndCOFFSymbolDef() {
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assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
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void WinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
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llvm_unreachable("not implemented");
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void WinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
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unsigned ByteAlignment) {
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AddCommonSymbol(Symbol, Size, ByteAlignment, true);
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void WinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
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AddCommonSymbol(Symbol, Size, 1, false);
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void WinCOFFStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
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unsigned Size,unsigned ByteAlignment) {
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llvm_unreachable("not implemented");
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void WinCOFFStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
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uint64_t Size, unsigned ByteAlignment) {
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llvm_unreachable("not implemented");
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void WinCOFFStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
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// TODO: This is copied exactly from the MachOStreamer. Consider merging into
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getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
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void WinCOFFStreamer::EmitValue(const MCExpr *Value, unsigned Size,
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unsigned AddrSpace) {
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assert(AddrSpace == 0 && "Address space must be 0!");
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// TODO: This is copied exactly from the MachOStreamer. Consider merging into
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MCDataFragment *DF = getOrCreateDataFragment();
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// Avoid fixups when possible.
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if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue)) {
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// FIXME: Endianness assumption.
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for (unsigned i = 0; i != Size; ++i)
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DF->getContents().push_back(uint8_t(AbsValue >> (i * 8)));
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DF->addFixup(MCFixup::Create(DF->getContents().size(),
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AddValueSymbols(Value),
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MCFixup::getKindForSize(Size)));
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DF->getContents().resize(DF->getContents().size() + Size, 0);
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void WinCOFFStreamer::EmitGPRel32Value(const MCExpr *Value) {
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llvm_unreachable("not implemented");
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void WinCOFFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
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unsigned MaxBytesToEmit) {
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// TODO: This is copied exactly from the MachOStreamer. Consider merging into
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if (MaxBytesToEmit == 0)
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MaxBytesToEmit = ByteAlignment;
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new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
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getCurrentSectionData());
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// Update the maximum alignment on the current section if necessary.
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if (ByteAlignment > getCurrentSectionData()->getAlignment())
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getCurrentSectionData()->setAlignment(ByteAlignment);
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void WinCOFFStreamer::EmitCodeAlignment(unsigned ByteAlignment,
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unsigned MaxBytesToEmit) {
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// TODO: This is copied exactly from the MachOStreamer. Consider merging into
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if (MaxBytesToEmit == 0)
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MaxBytesToEmit = ByteAlignment;
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MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
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getCurrentSectionData());
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F->setEmitNops(true);
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// Update the maximum alignment on the current section if necessary.
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if (ByteAlignment > getCurrentSectionData()->getAlignment())
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getCurrentSectionData()->setAlignment(ByteAlignment);
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void WinCOFFStreamer::EmitValueToOffset(const MCExpr *Offset,
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unsigned char Value) {
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llvm_unreachable("not implemented");
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void WinCOFFStreamer::EmitFileDirective(StringRef Filename) {
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// Ignore for now, linkers don't care, and proper debug
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// info will be a much large effort.
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void WinCOFFStreamer::EmitDwarfFileDirective(unsigned FileNo,
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StringRef Filename) {
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llvm_unreachable("not implemented");
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void WinCOFFStreamer::EmitInstruction(const MCInst &Instruction) {
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for (unsigned i = 0, e = Instruction.getNumOperands(); i != e; ++i)
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if (Instruction.getOperand(i).isExpr())
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AddValueSymbols(Instruction.getOperand(i).getExpr());
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getCurrentSectionData()->setHasInstructions(true);
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MCInstFragment *Fragment =
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new MCInstFragment(Instruction, getCurrentSectionData());
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raw_svector_ostream VecOS(Fragment->getCode());
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getAssembler().getEmitter().EncodeInstruction(Instruction, VecOS,
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Fragment->getFixups());
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void WinCOFFStreamer::Finish() {
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MCObjectStreamer::Finish();
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MCStreamer *createWinCOFFStreamer(MCContext &Context,
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TargetAsmBackend &TAB,
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WinCOFFStreamer *S = new WinCOFFStreamer(Context, TAB, CE, OS);
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S->getAssembler().setRelaxAll(RelaxAll);