/3rd_party/llvm/lib/MC/MCObjectStreamer.cpp
https://code.google.com/p/softart/ · C++ · 393 lines · 294 code · 63 blank · 36 comment · 32 complexity · 43f3adff5ece50116e446307bd92824d MD5 · raw file
- //===- lib/MC/MCObjectStreamer.cpp - Object File MCStreamer Interface -----===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is distributed under the University of Illinois Open Source
- // License. See LICENSE.TXT for details.
- //
- //===----------------------------------------------------------------------===//
- #include "llvm/MC/MCObjectStreamer.h"
- #include "llvm/ADT/STLExtras.h"
- #include "llvm/MC/MCAsmBackend.h"
- #include "llvm/MC/MCAsmInfo.h"
- #include "llvm/MC/MCAssembler.h"
- #include "llvm/MC/MCCodeEmitter.h"
- #include "llvm/MC/MCContext.h"
- #include "llvm/MC/MCDwarf.h"
- #include "llvm/MC/MCExpr.h"
- #include "llvm/MC/MCObjectWriter.h"
- #include "llvm/MC/MCSymbol.h"
- #include "llvm/MC/MCSection.h"
- #include "llvm/Support/ErrorHandling.h"
- using namespace llvm;
- MCObjectStreamer::MCObjectStreamer(MCContext &Context,
- MCTargetStreamer *TargetStreamer,
- MCAsmBackend &TAB, raw_ostream &OS,
- MCCodeEmitter *Emitter_)
- : MCStreamer(Context, TargetStreamer),
- Assembler(new MCAssembler(Context, TAB, *Emitter_,
- *TAB.createObjectWriter(OS), OS)),
- CurSectionData(0) {}
- MCObjectStreamer::MCObjectStreamer(MCContext &Context,
- MCTargetStreamer *TargetStreamer,
- MCAsmBackend &TAB, raw_ostream &OS,
- MCCodeEmitter *Emitter_,
- MCAssembler *_Assembler)
- : MCStreamer(Context, TargetStreamer), Assembler(_Assembler),
- CurSectionData(0) {}
- MCObjectStreamer::~MCObjectStreamer() {
- delete &Assembler->getBackend();
- delete &Assembler->getEmitter();
- delete &Assembler->getWriter();
- delete Assembler;
- }
- void MCObjectStreamer::reset() {
- if (Assembler)
- Assembler->reset();
- CurSectionData = 0;
- CurInsertionPoint = MCSectionData::iterator();
- MCStreamer::reset();
- }
- MCFragment *MCObjectStreamer::getCurrentFragment() const {
- assert(getCurrentSectionData() && "No current section!");
- if (CurInsertionPoint != getCurrentSectionData()->getFragmentList().begin())
- return prior(CurInsertionPoint);
- return 0;
- }
- MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
- MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
- // When bundling is enabled, we don't want to add data to a fragment that
- // already has instructions (see MCELFStreamer::EmitInstToData for details)
- if (!F || (Assembler->isBundlingEnabled() && F->hasInstructions())) {
- F = new MCDataFragment();
- insert(F);
- }
- return F;
- }
- const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
- switch (Value->getKind()) {
- case MCExpr::Target:
- cast<MCTargetExpr>(Value)->AddValueSymbols(Assembler);
- break;
- case MCExpr::Constant:
- break;
- case MCExpr::Binary: {
- const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
- AddValueSymbols(BE->getLHS());
- AddValueSymbols(BE->getRHS());
- break;
- }
- case MCExpr::SymbolRef:
- Assembler->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
- break;
- case MCExpr::Unary:
- AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
- break;
- }
- return Value;
- }
- void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size) {
- MCDataFragment *DF = getOrCreateDataFragment();
- MCLineEntry::Make(this, getCurrentSection().first);
- // Avoid fixups when possible.
- int64_t AbsValue;
- if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue, getAssembler())) {
- EmitIntValue(AbsValue, Size);
- return;
- }
- DF->getFixups().push_back(
- MCFixup::Create(DF->getContents().size(), Value,
- MCFixup::getKindForSize(Size, false)));
- DF->getContents().resize(DF->getContents().size() + Size, 0);
- }
- void MCObjectStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
- RecordProcStart(Frame);
- }
- void MCObjectStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
- RecordProcEnd(Frame);
- }
- void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
- MCStreamer::EmitLabel(Symbol);
- MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
- // FIXME: This is wasteful, we don't necessarily need to create a data
- // fragment. Instead, we should mark the symbol as pointing into the data
- // fragment if it exists, otherwise we should just queue the label and set its
- // fragment pointer when we emit the next fragment.
- MCDataFragment *F = getOrCreateDataFragment();
- assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
- SD.setFragment(F);
- SD.setOffset(F->getContents().size());
- }
- void MCObjectStreamer::EmitDebugLabel(MCSymbol *Symbol) {
- EmitLabel(Symbol);
- }
- void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
- int64_t IntValue;
- if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
- EmitULEB128IntValue(IntValue);
- return;
- }
- Value = ForceExpAbs(Value);
- insert(new MCLEBFragment(*Value, false));
- }
- void MCObjectStreamer::EmitSLEB128Value(const MCExpr *Value) {
- int64_t IntValue;
- if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
- EmitSLEB128IntValue(IntValue);
- return;
- }
- Value = ForceExpAbs(Value);
- insert(new MCLEBFragment(*Value, true));
- }
- void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
- const MCSymbol *Symbol) {
- report_fatal_error("This file format doesn't support weak aliases.");
- }
- void MCObjectStreamer::ChangeSection(const MCSection *Section,
- const MCExpr *Subsection) {
- assert(Section && "Cannot switch to a null section!");
- CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
- int64_t IntSubsection = 0;
- if (Subsection &&
- !Subsection->EvaluateAsAbsolute(IntSubsection, getAssembler()))
- report_fatal_error("Cannot evaluate subsection number");
- if (IntSubsection < 0 || IntSubsection > 8192)
- report_fatal_error("Subsection number out of range");
- CurInsertionPoint =
- CurSectionData->getSubsectionInsertionPoint(unsigned(IntSubsection));
- }
- void MCObjectStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
- getAssembler().getOrCreateSymbolData(*Symbol);
- Symbol->setVariableValue(AddValueSymbols(Value));
- }
- void MCObjectStreamer::EmitInstruction(const MCInst &Inst) {
- // Scan for values.
- for (unsigned i = Inst.getNumOperands(); i--; )
- if (Inst.getOperand(i).isExpr())
- AddValueSymbols(Inst.getOperand(i).getExpr());
- MCSectionData *SD = getCurrentSectionData();
- SD->setHasInstructions(true);
- // Now that a machine instruction has been assembled into this section, make
- // a line entry for any .loc directive that has been seen.
- MCLineEntry::Make(this, getCurrentSection().first);
- // If this instruction doesn't need relaxation, just emit it as data.
- MCAssembler &Assembler = getAssembler();
- if (!Assembler.getBackend().mayNeedRelaxation(Inst)) {
- EmitInstToData(Inst);
- return;
- }
- // Otherwise, relax and emit it as data if either:
- // - The RelaxAll flag was passed
- // - Bundling is enabled and this instruction is inside a bundle-locked
- // group. We want to emit all such instructions into the same data
- // fragment.
- if (Assembler.getRelaxAll() ||
- (Assembler.isBundlingEnabled() && SD->isBundleLocked())) {
- MCInst Relaxed;
- getAssembler().getBackend().relaxInstruction(Inst, Relaxed);
- while (getAssembler().getBackend().mayNeedRelaxation(Relaxed))
- getAssembler().getBackend().relaxInstruction(Relaxed, Relaxed);
- EmitInstToData(Relaxed);
- return;
- }
- // Otherwise emit to a separate fragment.
- EmitInstToFragment(Inst);
- }
- void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst) {
- // Always create a new, separate fragment here, because its size can change
- // during relaxation.
- MCRelaxableFragment *IF = new MCRelaxableFragment(Inst);
- insert(IF);
- SmallString<128> Code;
- raw_svector_ostream VecOS(Code);
- getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups());
- VecOS.flush();
- IF->getContents().append(Code.begin(), Code.end());
- }
- #ifndef NDEBUG
- static const char *const BundlingNotImplementedMsg =
- "Aligned bundling is not implemented for this object format";
- #endif
- void MCObjectStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
- llvm_unreachable(BundlingNotImplementedMsg);
- }
- void MCObjectStreamer::EmitBundleLock(bool AlignToEnd) {
- llvm_unreachable(BundlingNotImplementedMsg);
- }
- void MCObjectStreamer::EmitBundleUnlock() {
- llvm_unreachable(BundlingNotImplementedMsg);
- }
- void MCObjectStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
- unsigned Column, unsigned Flags,
- unsigned Isa,
- unsigned Discriminator,
- StringRef FileName) {
- // In case we see two .loc directives in a row, make sure the
- // first one gets a line entry.
- MCLineEntry::Make(this, getCurrentSection().first);
- this->MCStreamer::EmitDwarfLocDirective(FileNo, Line, Column, Flags,
- Isa, Discriminator, FileName);
- }
- void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
- const MCSymbol *LastLabel,
- const MCSymbol *Label,
- unsigned PointerSize) {
- if (!LastLabel) {
- EmitDwarfSetLineAddr(LineDelta, Label, PointerSize);
- return;
- }
- const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
- int64_t Res;
- if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
- MCDwarfLineAddr::Emit(this, LineDelta, Res);
- return;
- }
- AddrDelta = ForceExpAbs(AddrDelta);
- insert(new MCDwarfLineAddrFragment(LineDelta, *AddrDelta));
- }
- void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
- const MCSymbol *Label) {
- const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
- int64_t Res;
- if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
- MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
- return;
- }
- AddrDelta = ForceExpAbs(AddrDelta);
- insert(new MCDwarfCallFrameFragment(*AddrDelta));
- }
- void MCObjectStreamer::EmitBytes(StringRef Data) {
- MCLineEntry::Make(this, getCurrentSection().first);
- getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
- }
- void MCObjectStreamer::EmitValueToAlignment(unsigned ByteAlignment,
- int64_t Value,
- unsigned ValueSize,
- unsigned MaxBytesToEmit) {
- if (MaxBytesToEmit == 0)
- MaxBytesToEmit = ByteAlignment;
- insert(new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit));
- // Update the maximum alignment on the current section if necessary.
- if (ByteAlignment > getCurrentSectionData()->getAlignment())
- getCurrentSectionData()->setAlignment(ByteAlignment);
- }
- void MCObjectStreamer::EmitCodeAlignment(unsigned ByteAlignment,
- unsigned MaxBytesToEmit) {
- EmitValueToAlignment(ByteAlignment, 0, 1, MaxBytesToEmit);
- cast<MCAlignFragment>(getCurrentFragment())->setEmitNops(true);
- }
- bool MCObjectStreamer::EmitValueToOffset(const MCExpr *Offset,
- unsigned char Value) {
- int64_t Res;
- if (Offset->EvaluateAsAbsolute(Res, getAssembler())) {
- insert(new MCOrgFragment(*Offset, Value));
- return false;
- }
- MCSymbol *CurrentPos = getContext().CreateTempSymbol();
- EmitLabel(CurrentPos);
- MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
- const MCExpr *Ref =
- MCSymbolRefExpr::Create(CurrentPos, Variant, getContext());
- const MCExpr *Delta =
- MCBinaryExpr::Create(MCBinaryExpr::Sub, Offset, Ref, getContext());
- if (!Delta->EvaluateAsAbsolute(Res, getAssembler()))
- return true;
- EmitFill(Res, Value);
- return false;
- }
- // Associate GPRel32 fixup with data and resize data area
- void MCObjectStreamer::EmitGPRel32Value(const MCExpr *Value) {
- MCDataFragment *DF = getOrCreateDataFragment();
- DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
- Value, FK_GPRel_4));
- DF->getContents().resize(DF->getContents().size() + 4, 0);
- }
- // Associate GPRel32 fixup with data and resize data area
- void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
- MCDataFragment *DF = getOrCreateDataFragment();
- DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
- Value, FK_GPRel_4));
- DF->getContents().resize(DF->getContents().size() + 8, 0);
- }
- void MCObjectStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue) {
- // FIXME: A MCFillFragment would be more memory efficient but MCExpr has
- // problems evaluating expressions across multiple fragments.
- getOrCreateDataFragment()->getContents().append(NumBytes, FillValue);
- }
- void MCObjectStreamer::EmitZeros(uint64_t NumBytes) {
- unsigned ItemSize = getCurrentSection().first->isVirtualSection() ? 0 : 1;
- insert(new MCFillFragment(0, ItemSize, NumBytes));
- }
- void MCObjectStreamer::FinishImpl() {
- // Dump out the dwarf file & directory tables and line tables.
- const MCSymbol *LineSectionSymbol = NULL;
- if (getContext().hasDwarfFiles())
- LineSectionSymbol = MCDwarfFileTable::Emit(this);
- // If we are generating dwarf for assembly source files dump out the sections.
- if (getContext().getGenDwarfForAssembly())
- MCGenDwarfInfo::Emit(this, LineSectionSymbol);
- getAssembler().Finish();
- }