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- //===-- llvm/MC/WinCOFFStreamer.cpp -----------------------------*- C++ -*-===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is distributed under the University of Illinois Open Source
- // License. See LICENSE.TXT for details.
- //
- //===----------------------------------------------------------------------===//
- //
- // This file contains an implementation of a Windows COFF object file streamer.
- //
- //===----------------------------------------------------------------------===//
- #include "llvm/MC/MCAsmBackend.h"
- #include "llvm/MC/MCAsmLayout.h"
- #include "llvm/MC/MCAssembler.h"
- #include "llvm/MC/MCCodeEmitter.h"
- #include "llvm/MC/MCContext.h"
- #include "llvm/MC/MCExpr.h"
- #include "llvm/MC/MCObjectFileInfo.h"
- #include "llvm/MC/MCObjectStreamer.h"
- #include "llvm/MC/MCSection.h"
- #include "llvm/MC/MCSectionCOFF.h"
- #include "llvm/MC/MCStreamer.h"
- #include "llvm/MC/MCSymbolCOFF.h"
- #include "llvm/MC/MCValue.h"
- #include "llvm/MC/MCWinCOFFStreamer.h"
- #include "llvm/Support/COFF.h"
- #include "llvm/Support/Debug.h"
- #include "llvm/Support/ErrorHandling.h"
- #include "llvm/Support/MathExtras.h"
- #include "llvm/Support/TargetRegistry.h"
- #include "llvm/Support/raw_ostream.h"
- using namespace llvm;
- #define DEBUG_TYPE "WinCOFFStreamer"
- namespace llvm {
- MCWinCOFFStreamer::MCWinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
- MCCodeEmitter &CE, raw_pwrite_stream &OS)
- : MCObjectStreamer(Context, MAB, OS, &CE), CurSymbol(nullptr) {}
- void MCWinCOFFStreamer::EmitInstToData(const MCInst &Inst,
- const MCSubtargetInfo &STI) {
- MCDataFragment *DF = getOrCreateDataFragment();
- SmallVector<MCFixup, 4> Fixups;
- SmallString<256> Code;
- raw_svector_ostream VecOS(Code);
- getAssembler().getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
- VecOS.flush();
- // Add the fixups and data.
- for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
- Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
- DF->getFixups().push_back(Fixups[i]);
- }
- DF->getContents().append(Code.begin(), Code.end());
- }
- void MCWinCOFFStreamer::InitSections(bool NoExecStack) {
- // FIXME: this is identical to the ELF one.
- // This emulates the same behavior of GNU as. This makes it easier
- // to compare the output as the major sections are in the same order.
- SwitchSection(getContext().getObjectFileInfo()->getTextSection());
- EmitCodeAlignment(4);
- SwitchSection(getContext().getObjectFileInfo()->getDataSection());
- EmitCodeAlignment(4);
- SwitchSection(getContext().getObjectFileInfo()->getBSSSection());
- EmitCodeAlignment(4);
- SwitchSection(getContext().getObjectFileInfo()->getTextSection());
- }
- void MCWinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
- assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
- MCObjectStreamer::EmitLabel(Symbol);
- }
- void MCWinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
- llvm_unreachable("not implemented");
- }
- void MCWinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
- llvm_unreachable("not implemented");
- }
- bool MCWinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
- MCSymbolAttr Attribute) {
- assert(Symbol && "Symbol must be non-null!");
- assert((!Symbol->isInSection() ||
- Symbol->getSection().getVariant() == MCSection::SV_COFF) &&
- "Got non-COFF section in the COFF backend!");
- getAssembler().registerSymbol(*Symbol);
- switch (Attribute) {
- default: return false;
- case MCSA_WeakReference:
- case MCSA_Weak:
- cast<MCSymbolCOFF>(Symbol)->setIsWeakExternal();
- Symbol->setExternal(true);
- break;
- case MCSA_Global:
- Symbol->setExternal(true);
- break;
- }
- return true;
- }
- void MCWinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
- llvm_unreachable("not implemented");
- }
- void MCWinCOFFStreamer::BeginCOFFSymbolDef(MCSymbol const *Symbol) {
- assert((!Symbol->isInSection() ||
- Symbol->getSection().getVariant() == MCSection::SV_COFF) &&
- "Got non-COFF section in the COFF backend!");
- if (CurSymbol)
- FatalError("starting a new symbol definition without completing the "
- "previous one");
- CurSymbol = Symbol;
- }
- void MCWinCOFFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
- if (!CurSymbol)
- FatalError("storage class specified outside of symbol definition");
- if (StorageClass & ~COFF::SSC_Invalid)
- FatalError("storage class value '" + Twine(StorageClass) +
- "' out of range");
- getAssembler().registerSymbol(*CurSymbol);
- cast<MCSymbolCOFF>(CurSymbol)->setClass((uint16_t)StorageClass);
- }
- void MCWinCOFFStreamer::EmitCOFFSymbolType(int Type) {
- if (!CurSymbol)
- FatalError("symbol type specified outside of a symbol definition");
- if (Type & ~0xffff)
- FatalError("type value '" + Twine(Type) + "' out of range");
- getAssembler().registerSymbol(*CurSymbol);
- cast<MCSymbolCOFF>(CurSymbol)->setType((uint16_t)Type);
- }
- void MCWinCOFFStreamer::EndCOFFSymbolDef() {
- if (!CurSymbol)
- FatalError("ending symbol definition without starting one");
- CurSymbol = nullptr;
- }
- void MCWinCOFFStreamer::EmitCOFFSafeSEH(MCSymbol const *Symbol) {
- // SafeSEH is a feature specific to 32-bit x86. It does not exist (and is
- // unnecessary) on all platforms which use table-based exception dispatch.
- if (getContext().getObjectFileInfo()->getTargetTriple().getArch() !=
- Triple::x86)
- return;
- const MCSymbolCOFF *CSymbol = cast<MCSymbolCOFF>(Symbol);
- if (CSymbol->isSafeSEH())
- return;
- MCSection *SXData = getContext().getObjectFileInfo()->getSXDataSection();
- getAssembler().registerSection(*SXData);
- if (SXData->getAlignment() < 4)
- SXData->setAlignment(4);
- new MCSafeSEHFragment(Symbol, SXData);
- getAssembler().registerSymbol(*Symbol);
- CSymbol->setIsSafeSEH();
- // The Microsoft linker requires that the symbol type of a handler be
- // function. Go ahead and oblige it here.
- CSymbol->setType(COFF::IMAGE_SYM_DTYPE_FUNCTION
- << COFF::SCT_COMPLEX_TYPE_SHIFT);
- }
- void MCWinCOFFStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
- MCDataFragment *DF = getOrCreateDataFragment();
- const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext());
- MCFixup Fixup = MCFixup::create(DF->getContents().size(), SRE, FK_SecRel_2);
- DF->getFixups().push_back(Fixup);
- DF->getContents().resize(DF->getContents().size() + 2, 0);
- }
- void MCWinCOFFStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
- MCDataFragment *DF = getOrCreateDataFragment();
- const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext());
- MCFixup Fixup = MCFixup::create(DF->getContents().size(), SRE, FK_SecRel_4);
- DF->getFixups().push_back(Fixup);
- DF->getContents().resize(DF->getContents().size() + 4, 0);
- }
- void MCWinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
- unsigned ByteAlignment) {
- assert((!Symbol->isInSection() ||
- Symbol->getSection().getVariant() == MCSection::SV_COFF) &&
- "Got non-COFF section in the COFF backend!");
- const Triple &T = getContext().getObjectFileInfo()->getTargetTriple();
- if (T.isKnownWindowsMSVCEnvironment()) {
- if (ByteAlignment > 32)
- report_fatal_error("alignment is limited to 32-bytes");
- // Round size up to alignment so that we will honor the alignment request.
- Size = std::max(Size, static_cast<uint64_t>(ByteAlignment));
- }
- AssignSection(Symbol, nullptr);
- getAssembler().registerSymbol(*Symbol);
- Symbol->setExternal(true);
- Symbol->setCommon(Size, ByteAlignment);
- if (!T.isKnownWindowsMSVCEnvironment() && ByteAlignment > 1) {
- SmallString<128> Directive;
- raw_svector_ostream OS(Directive);
- const MCObjectFileInfo *MFI = getContext().getObjectFileInfo();
- OS << " -aligncomm:\"" << Symbol->getName() << "\","
- << Log2_32_Ceil(ByteAlignment);
- OS.flush();
- PushSection();
- SwitchSection(MFI->getDrectveSection());
- EmitBytes(Directive);
- PopSection();
- }
- }
- void MCWinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
- unsigned ByteAlignment) {
- assert(!Symbol->isInSection() && "Symbol must not already have a section!");
- MCSection *Section = getContext().getObjectFileInfo()->getBSSSection();
- getAssembler().registerSection(*Section);
- if (Section->getAlignment() < ByteAlignment)
- Section->setAlignment(ByteAlignment);
- getAssembler().registerSymbol(*Symbol);
- Symbol->setExternal(false);
- AssignSection(Symbol, Section);
- if (ByteAlignment != 1)
- new MCAlignFragment(ByteAlignment, /*Value=*/0, /*ValueSize=*/0,
- ByteAlignment, Section);
- MCFillFragment *Fragment = new MCFillFragment(
- /*Value=*/0, /*ValueSize=*/0, Size, Section);
- Symbol->setFragment(Fragment);
- }
- void MCWinCOFFStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
- uint64_t Size, unsigned ByteAlignment) {
- llvm_unreachable("not implemented");
- }
- void MCWinCOFFStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
- uint64_t Size, unsigned ByteAlignment) {
- llvm_unreachable("not implemented");
- }
- void MCWinCOFFStreamer::EmitFileDirective(StringRef Filename) {
- getAssembler().addFileName(Filename);
- }
- // TODO: Implement this if you want to emit .comment section in COFF obj files.
- void MCWinCOFFStreamer::EmitIdent(StringRef IdentString) {
- llvm_unreachable("not implemented");
- }
- void MCWinCOFFStreamer::EmitWinEHHandlerData() {
- llvm_unreachable("not implemented");
- }
- void MCWinCOFFStreamer::FinishImpl() {
- MCObjectStreamer::FinishImpl();
- }
- LLVM_ATTRIBUTE_NORETURN
- void MCWinCOFFStreamer::FatalError(const Twine &Msg) const {
- getContext().reportFatalError(SMLoc(), Msg);
- }
- }
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