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https://github.com/c64scene-ar/llvm-6502.git
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4df4bccc71
The compiler occasionally generates multiple .loc directives in a row (at the same instruction address). These need to be transformed into multple actual .debug_line table entries, since they are used to signal certain information to the debugger (e.g. if the opening brace of a function body is on the same line as the declaration). The MCAsmStreamer version of EmitDwarfLocDirective handles this correctly by emitting a .loc directive every time it is called. However, the MCObjectStream version simply defaults to recording the information and emitting only a single table entry later, e.g. when EmitInstruction is called. This patch introduces a MCAsmStreamer::EmitDwarfLocDirective version that emits a line table entry for a .loc directive that may already be pending before recording the new directive. (This is similar to how this is handled in GNU as.) With this patch (and the code alignment factor patch) applied, I'm now getting identical DWARF .debug sections for all test-suite object files on PowerPC for the internal and the external assembler. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184357 91177308-0d34-0410-b5e6-96231b3b80d8
389 lines
14 KiB
C++
389 lines
14 KiB
C++
//===- lib/MC/MCObjectStreamer.cpp - Object File MCStreamer Interface -----===//
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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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#include "llvm/MC/MCObjectStreamer.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/MC/MCAsmBackend.h"
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#include "llvm/MC/MCAsmInfo.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/MCDwarf.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCObjectWriter.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/Support/ErrorHandling.h"
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using namespace llvm;
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MCObjectStreamer::MCObjectStreamer(StreamerKind Kind, MCContext &Context,
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MCAsmBackend &TAB, raw_ostream &OS,
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MCCodeEmitter *Emitter_)
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: MCStreamer(Kind, Context),
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Assembler(new MCAssembler(Context, TAB, *Emitter_,
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*TAB.createObjectWriter(OS), OS)),
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CurSectionData(0) {}
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MCObjectStreamer::MCObjectStreamer(StreamerKind Kind, MCContext &Context,
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MCAsmBackend &TAB, raw_ostream &OS,
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MCCodeEmitter *Emitter_,
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MCAssembler *_Assembler)
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: MCStreamer(Kind, Context), Assembler(_Assembler), CurSectionData(0) {}
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MCObjectStreamer::~MCObjectStreamer() {
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delete &Assembler->getBackend();
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delete &Assembler->getEmitter();
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delete &Assembler->getWriter();
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delete Assembler;
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}
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void MCObjectStreamer::reset() {
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if (Assembler)
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Assembler->reset();
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CurSectionData = 0;
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CurInsertionPoint = MCSectionData::iterator();
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MCStreamer::reset();
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}
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MCFragment *MCObjectStreamer::getCurrentFragment() const {
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assert(getCurrentSectionData() && "No current section!");
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if (CurInsertionPoint != getCurrentSectionData()->getFragmentList().begin())
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return prior(CurInsertionPoint);
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return 0;
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}
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MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
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MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
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// When bundling is enabled, we don't want to add data to a fragment that
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// already has instructions (see MCELFStreamer::EmitInstToData for details)
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if (!F || (Assembler->isBundlingEnabled() && F->hasInstructions())) {
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F = new MCDataFragment();
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insert(F);
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}
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return F;
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}
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const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
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switch (Value->getKind()) {
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case MCExpr::Target:
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cast<MCTargetExpr>(Value)->AddValueSymbols(Assembler);
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break;
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case MCExpr::Constant:
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break;
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case MCExpr::Binary: {
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const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
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AddValueSymbols(BE->getLHS());
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AddValueSymbols(BE->getRHS());
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break;
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}
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case MCExpr::SymbolRef:
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Assembler->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
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break;
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case MCExpr::Unary:
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AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
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break;
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}
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return Value;
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}
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void MCObjectStreamer::EmitValueImpl(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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MCDataFragment *DF = getOrCreateDataFragment();
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MCLineEntry::Make(this, getCurrentSection().first);
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// Avoid fixups when possible.
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int64_t AbsValue;
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if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue, getAssembler())) {
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EmitIntValue(AbsValue, Size, AddrSpace);
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return;
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}
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DF->getFixups().push_back(
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MCFixup::Create(DF->getContents().size(), Value,
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MCFixup::getKindForSize(Size, false)));
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DF->getContents().resize(DF->getContents().size() + Size, 0);
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}
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void MCObjectStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
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RecordProcStart(Frame);
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}
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void MCObjectStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
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RecordProcEnd(Frame);
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}
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void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
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MCStreamer::EmitLabel(Symbol);
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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 *F = getOrCreateDataFragment();
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assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
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SD.setFragment(F);
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SD.setOffset(F->getContents().size());
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}
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void MCObjectStreamer::EmitDebugLabel(MCSymbol *Symbol) {
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EmitLabel(Symbol);
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}
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void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
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int64_t IntValue;
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if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
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EmitULEB128IntValue(IntValue);
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return;
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}
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Value = ForceExpAbs(Value);
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insert(new MCLEBFragment(*Value, false));
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}
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void MCObjectStreamer::EmitSLEB128Value(const MCExpr *Value) {
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int64_t IntValue;
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if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
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EmitSLEB128IntValue(IntValue);
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return;
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}
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Value = ForceExpAbs(Value);
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insert(new MCLEBFragment(*Value, true));
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}
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void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
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const MCSymbol *Symbol) {
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report_fatal_error("This file format doesn't support weak aliases.");
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}
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void MCObjectStreamer::ChangeSection(const MCSection *Section,
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const MCExpr *Subsection) {
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assert(Section && "Cannot switch to a null section!");
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CurSectionData = &getAssembler().getOrCreateSectionData(*Section);
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int64_t IntSubsection = 0;
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if (Subsection &&
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!Subsection->EvaluateAsAbsolute(IntSubsection, getAssembler()))
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report_fatal_error("Cannot evaluate subsection number");
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if (IntSubsection < 0 || IntSubsection > 8192)
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report_fatal_error("Subsection number out of range");
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CurInsertionPoint =
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CurSectionData->getSubsectionInsertionPoint(unsigned(IntSubsection));
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}
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void MCObjectStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
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getAssembler().getOrCreateSymbolData(*Symbol);
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Symbol->setVariableValue(AddValueSymbols(Value));
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}
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void MCObjectStreamer::EmitInstruction(const MCInst &Inst) {
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// Scan for values.
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for (unsigned i = Inst.getNumOperands(); i--; )
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if (Inst.getOperand(i).isExpr())
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AddValueSymbols(Inst.getOperand(i).getExpr());
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MCSectionData *SD = getCurrentSectionData();
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SD->setHasInstructions(true);
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// Now that a machine instruction has been assembled into this section, make
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// a line entry for any .loc directive that has been seen.
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MCLineEntry::Make(this, getCurrentSection().first);
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// If this instruction doesn't need relaxation, just emit it as data.
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MCAssembler &Assembler = getAssembler();
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if (!Assembler.getBackend().mayNeedRelaxation(Inst)) {
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EmitInstToData(Inst);
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return;
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}
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// Otherwise, relax and emit it as data if either:
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// - The RelaxAll flag was passed
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// - Bundling is enabled and this instruction is inside a bundle-locked
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// group. We want to emit all such instructions into the same data
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// fragment.
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if (Assembler.getRelaxAll() ||
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(Assembler.isBundlingEnabled() && SD->isBundleLocked())) {
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MCInst Relaxed;
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getAssembler().getBackend().relaxInstruction(Inst, Relaxed);
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while (getAssembler().getBackend().mayNeedRelaxation(Relaxed))
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getAssembler().getBackend().relaxInstruction(Relaxed, Relaxed);
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EmitInstToData(Relaxed);
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return;
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}
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// Otherwise emit to a separate fragment.
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EmitInstToFragment(Inst);
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}
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void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst) {
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// Always create a new, separate fragment here, because its size can change
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// during relaxation.
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MCRelaxableFragment *IF = new MCRelaxableFragment(Inst);
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insert(IF);
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SmallString<128> Code;
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raw_svector_ostream VecOS(Code);
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getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups());
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VecOS.flush();
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IF->getContents().append(Code.begin(), Code.end());
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}
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#ifndef NDEBUG
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static const char *BundlingNotImplementedMsg =
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"Aligned bundling is not implemented for this object format";
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#endif
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void MCObjectStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
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llvm_unreachable(BundlingNotImplementedMsg);
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}
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void MCObjectStreamer::EmitBundleLock(bool AlignToEnd) {
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llvm_unreachable(BundlingNotImplementedMsg);
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}
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void MCObjectStreamer::EmitBundleUnlock() {
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llvm_unreachable(BundlingNotImplementedMsg);
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}
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void MCObjectStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
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unsigned Column, unsigned Flags,
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unsigned Isa,
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unsigned Discriminator,
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StringRef FileName) {
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// In case we see two .loc directives in a row, make sure the
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// first one gets a line entry.
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MCLineEntry::Make(this, getCurrentSection().first);
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this->MCStreamer::EmitDwarfLocDirective(FileNo, Line, Column, Flags,
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Isa, Discriminator, FileName);
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}
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void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
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const MCSymbol *LastLabel,
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const MCSymbol *Label,
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unsigned PointerSize) {
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if (!LastLabel) {
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EmitDwarfSetLineAddr(LineDelta, Label, PointerSize);
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return;
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}
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const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
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int64_t Res;
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if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
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MCDwarfLineAddr::Emit(this, LineDelta, Res);
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return;
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}
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AddrDelta = ForceExpAbs(AddrDelta);
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insert(new MCDwarfLineAddrFragment(LineDelta, *AddrDelta));
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}
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void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
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const MCSymbol *Label) {
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const MCExpr *AddrDelta = BuildSymbolDiff(getContext(), Label, LastLabel);
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int64_t Res;
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if (AddrDelta->EvaluateAsAbsolute(Res, getAssembler())) {
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MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
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return;
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}
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AddrDelta = ForceExpAbs(AddrDelta);
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insert(new MCDwarfCallFrameFragment(*AddrDelta));
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}
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void MCObjectStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
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assert(AddrSpace == 0 && "Address space must be 0!");
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getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
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}
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void MCObjectStreamer::EmitValueToAlignment(unsigned ByteAlignment,
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int64_t Value,
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unsigned ValueSize,
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unsigned MaxBytesToEmit) {
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if (MaxBytesToEmit == 0)
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MaxBytesToEmit = ByteAlignment;
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insert(new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit));
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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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}
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void MCObjectStreamer::EmitCodeAlignment(unsigned ByteAlignment,
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unsigned MaxBytesToEmit) {
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EmitValueToAlignment(ByteAlignment, 0, 1, MaxBytesToEmit);
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cast<MCAlignFragment>(getCurrentFragment())->setEmitNops(true);
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}
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bool MCObjectStreamer::EmitValueToOffset(const MCExpr *Offset,
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unsigned char Value) {
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int64_t Res;
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if (Offset->EvaluateAsAbsolute(Res, getAssembler())) {
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insert(new MCOrgFragment(*Offset, Value));
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return false;
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}
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MCSymbol *CurrentPos = getContext().CreateTempSymbol();
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EmitLabel(CurrentPos);
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MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
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const MCExpr *Ref =
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MCSymbolRefExpr::Create(CurrentPos, Variant, getContext());
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const MCExpr *Delta =
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MCBinaryExpr::Create(MCBinaryExpr::Sub, Offset, Ref, getContext());
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if (!Delta->EvaluateAsAbsolute(Res, getAssembler()))
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return true;
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EmitFill(Res, Value);
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return false;
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}
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// Associate GPRel32 fixup with data and resize data area
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void MCObjectStreamer::EmitGPRel32Value(const MCExpr *Value) {
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MCDataFragment *DF = getOrCreateDataFragment();
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DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
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Value, FK_GPRel_4));
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DF->getContents().resize(DF->getContents().size() + 4, 0);
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}
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// Associate GPRel32 fixup with data and resize data area
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void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
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MCDataFragment *DF = getOrCreateDataFragment();
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DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
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Value, FK_GPRel_4));
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DF->getContents().resize(DF->getContents().size() + 8, 0);
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}
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void MCObjectStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue,
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unsigned AddrSpace) {
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assert(AddrSpace == 0 && "Address space must be 0!");
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// FIXME: A MCFillFragment would be more memory efficient but MCExpr has
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// problems evaluating expressions across multiple fragments.
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getOrCreateDataFragment()->getContents().append(NumBytes, FillValue);
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}
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void MCObjectStreamer::FinishImpl() {
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// Dump out the dwarf file & directory tables and line tables.
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const MCSymbol *LineSectionSymbol = NULL;
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if (getContext().hasDwarfFiles())
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LineSectionSymbol = MCDwarfFileTable::Emit(this);
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// If we are generating dwarf for assembly source files dump out the sections.
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if (getContext().getGenDwarfForAssembly())
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MCGenDwarfInfo::Emit(this, LineSectionSymbol);
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getAssembler().Finish();
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}
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