mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-07-22 09:29:31 +00:00
e4d89ec8de
Summary: Local common symbols were properly inserted into the .bss section. However, putting external common symbols in the .bss section would give them a strong definition. Instead, encode them as undefined, external symbols who's symbol value is equivalent to their size. Reviewers: Bigcheese, rafael, rnk CC: llvm-commits Differential Revision: http://reviews.llvm.org/D3324 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205811 91177308-0d34-0410-b5e6-96231b3b80d8
304 lines
11 KiB
C++
304 lines
11 KiB
C++
//===-- llvm/MC/WinCOFFStreamer.cpp -----------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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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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//===----------------------------------------------------------------------===//
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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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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "WinCOFFStreamer"
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#include "llvm/MC/MCStreamer.h"
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#include "llvm/MC/MCAsmBackend.h"
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#include "llvm/MC/MCAsmLayout.h"
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCCodeEmitter.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCObjectFileInfo.h"
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#include "llvm/MC/MCObjectStreamer.h"
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#include "llvm/MC/MCSection.h"
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#include "llvm/MC/MCSectionCOFF.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/MC/MCWin64EH.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/TargetRegistry.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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namespace {
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class WinCOFFStreamer : public MCObjectStreamer {
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public:
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MCSymbol const *CurSymbol;
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WinCOFFStreamer(MCContext &Context,
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MCAsmBackend &MAB,
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MCCodeEmitter &CE,
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raw_ostream &OS);
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// MCStreamer interface
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void InitSections() override;
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void EmitLabel(MCSymbol *Symbol) override;
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void EmitDebugLabel(MCSymbol *Symbol) override;
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void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
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void EmitThumbFunc(MCSymbol *Func) override;
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bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
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void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) override;
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void BeginCOFFSymbolDef(MCSymbol const *Symbol) override;
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void EmitCOFFSymbolStorageClass(int StorageClass) override;
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void EmitCOFFSymbolType(int Type) override;
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void EndCOFFSymbolDef() override;
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void EmitCOFFSectionIndex(MCSymbol const *Symbol) override;
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void EmitCOFFSecRel32(MCSymbol const *Symbol) override;
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void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) override;
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void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
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unsigned ByteAlignment) override;
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void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
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unsigned ByteAlignment) override;
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void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
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uint64_t Size,unsigned ByteAlignment) override;
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void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
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uint64_t Size, unsigned ByteAlignment) override;
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void EmitFileDirective(StringRef Filename) override;
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void EmitIdent(StringRef IdentString) override;
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void EmitWin64EHHandlerData() override;
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void FinishImpl() override;
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private:
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void EmitInstToData(const MCInst &Inst, const MCSubtargetInfo &STI) override {
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MCDataFragment *DF = getOrCreateDataFragment();
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SmallVector<MCFixup, 4> Fixups;
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SmallString<256> Code;
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raw_svector_ostream VecOS(Code);
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getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups, STI);
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VecOS.flush();
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// Add the fixups and data.
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for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
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Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
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DF->getFixups().push_back(Fixups[i]);
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}
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DF->getContents().append(Code.begin(), Code.end());
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}
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};
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} // end anonymous namespace.
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WinCOFFStreamer::WinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
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MCCodeEmitter &CE, raw_ostream &OS)
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: MCObjectStreamer(Context, MAB, OS, &CE), CurSymbol(NULL) {}
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// MCStreamer interface
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void WinCOFFStreamer::InitSections() {
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// FIXME: this is identical to the ELF one.
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// This emulates the same behavior of GNU as. This makes it easier
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// to compare the output as the major sections are in the same order.
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SwitchSection(getContext().getObjectFileInfo()->getTextSection());
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EmitCodeAlignment(4);
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SwitchSection(getContext().getObjectFileInfo()->getDataSection());
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EmitCodeAlignment(4);
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SwitchSection(getContext().getObjectFileInfo()->getBSSSection());
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EmitCodeAlignment(4);
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SwitchSection(getContext().getObjectFileInfo()->getTextSection());
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}
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void WinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
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assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
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MCObjectStreamer::EmitLabel(Symbol);
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}
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void WinCOFFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
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EmitLabel(Symbol);
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}
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void WinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
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llvm_unreachable("not implemented");
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}
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void WinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
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llvm_unreachable("not implemented");
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}
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bool WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
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MCSymbolAttr Attribute) {
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assert(Symbol && "Symbol must be non-null!");
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assert((Symbol->isInSection()
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? Symbol->getSection().getVariant() == MCSection::SV_COFF
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: true) && "Got non-COFF section in the COFF backend!");
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switch (Attribute) {
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case MCSA_WeakReference:
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case MCSA_Weak: {
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MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
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SD.modifyFlags(COFF::SF_WeakExternal, COFF::SF_WeakExternal);
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SD.setExternal(true);
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}
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break;
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case MCSA_Global:
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getAssembler().getOrCreateSymbolData(*Symbol).setExternal(true);
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break;
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default:
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return false;
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}
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return true;
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}
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void WinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
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llvm_unreachable("not implemented");
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}
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void WinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
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assert((Symbol->isInSection()
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? Symbol->getSection().getVariant() == MCSection::SV_COFF
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: true) && "Got non-COFF section in the COFF backend!");
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assert(CurSymbol == NULL && "EndCOFFSymbolDef must be called between calls "
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"to BeginCOFFSymbolDef!");
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CurSymbol = Symbol;
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}
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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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"the first byte!");
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getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
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StorageClass << COFF::SF_ClassShift,
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COFF::SF_ClassMask);
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}
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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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"bytes");
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getAssembler().getOrCreateSymbolData(*CurSymbol).modifyFlags(
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Type << COFF::SF_TypeShift,
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COFF::SF_TypeMask);
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}
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void WinCOFFStreamer::EndCOFFSymbolDef() {
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assert(CurSymbol != NULL && "BeginCOFFSymbolDef must be called first!");
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CurSymbol = NULL;
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}
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void WinCOFFStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
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MCDataFragment *DF = getOrCreateDataFragment();
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DF->getFixups().push_back(MCFixup::Create(
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DF->getContents().size(), MCSymbolRefExpr::Create(Symbol, getContext()),
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FK_SecRel_2));
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DF->getContents().resize(DF->getContents().size() + 4, 0);
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}
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void WinCOFFStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
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MCDataFragment *DF = getOrCreateDataFragment();
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DF->getFixups().push_back(MCFixup::Create(
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DF->getContents().size(), MCSymbolRefExpr::Create(Symbol, getContext()),
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FK_SecRel_4));
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DF->getContents().resize(DF->getContents().size() + 4, 0);
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}
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void WinCOFFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
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llvm_unreachable("not implemented");
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}
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void WinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
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unsigned ByteAlignment) {
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assert((Symbol->isInSection()
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? Symbol->getSection().getVariant() == MCSection::SV_COFF
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: true) && "Got non-COFF section in the COFF backend!");
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if (ByteAlignment > 32)
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report_fatal_error(
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"The linker won't align common symbols beyond 32 bytes.");
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AssignSection(Symbol, NULL);
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MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
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SD.setExternal(true);
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SD.setCommon(Size, ByteAlignment);
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}
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void WinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
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unsigned ByteAlignment) {
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assert(!Symbol->isInSection() && "Symbol must not already have a section!");
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const MCSection *Section = getContext().getObjectFileInfo()->getBSSSection();
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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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MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
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SD.setExternal(false);
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AssignSection(Symbol, Section);
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if (ByteAlignment != 1)
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new MCAlignFragment(ByteAlignment, /*_Value=*/0, /*_ValueSize=*/0,
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ByteAlignment, &SectionData);
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SD.setFragment(
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new MCFillFragment(/*_Value=*/0, /*_ValueSize=*/0, Size, &SectionData));
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}
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void WinCOFFStreamer::EmitZerofill(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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}
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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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}
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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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}
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// TODO: Implement this if you want to emit .comment section in COFF obj files.
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void WinCOFFStreamer::EmitIdent(StringRef IdentString) {
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llvm_unreachable("unsupported directive");
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}
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void WinCOFFStreamer::EmitWin64EHHandlerData() {
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MCStreamer::EmitWin64EHHandlerData();
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// We have to emit the unwind info now, because this directive
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// actually switches to the .xdata section!
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MCWin64EHUnwindEmitter::EmitUnwindInfo(*this, getCurrentW64UnwindInfo());
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}
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void WinCOFFStreamer::FinishImpl() {
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EmitFrames(NULL, true);
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EmitW64Tables();
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MCObjectStreamer::FinishImpl();
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}
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namespace llvm
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{
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MCStreamer *createWinCOFFStreamer(MCContext &Context,
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MCAsmBackend &MAB,
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MCCodeEmitter &CE,
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raw_ostream &OS,
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bool RelaxAll) {
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WinCOFFStreamer *S = new WinCOFFStreamer(Context, MAB, CE, OS);
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S->getAssembler().setRelaxAll(RelaxAll);
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return S;
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}
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}
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