llvm-6502/lib/MC/MCObjectStreamer.cpp
David Blaikie c4e1b13b08 DebugInfo: Don't include the name of the CU file in the line table file list when it's unneeded
Recommitting r201380 (reverted in r201389)
Recommitting r201351 and r201355 (reverted in r201351 and r201355)

We weren't emitting the an empty (header only) line table when the line
table was empty - this made the DWARF invalid (the compile unit would
point to the zero-size debug_lines section where there should've been an
empty line table but there was nothing at all). Fix that, and as a
consequence this works around/addresses PR18809.

Also, we emit a non-empty line table to workaround a darwin linker bug,
so XFAILing on darwin too.

Also, mark the test as 'REQUIRES: object-emission' because it does.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201429 91177308-0d34-0410-b5e6-96231b3b80d8
2014-02-14 19:51:35 +00:00

392 lines
14 KiB
C++

//===- 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/MCSection.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
MCObjectStreamer::MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB,
raw_ostream &OS, MCCodeEmitter *Emitter_)
: MCStreamer(Context),
Assembler(new MCAssembler(Context, TAB, *Emitter_,
*TAB.createObjectWriter(OS), OS)),
CurSectionData(0) {}
MCObjectStreamer::MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB,
raw_ostream &OS, MCCodeEmitter *Emitter_,
MCAssembler *_Assembler)
: MCStreamer(Context), 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, const MCSubtargetInfo &STI) {
// 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, STI);
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, STI);
return;
}
// Otherwise emit to a separate fragment.
EmitInstToFragment(Inst, STI);
}
void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst,
const MCSubtargetInfo &STI) {
// Always create a new, separate fragment here, because its size can change
// during relaxation.
MCRelaxableFragment *IF = new MCRelaxableFragment(Inst, STI);
insert(IF);
SmallString<128> Code;
raw_svector_ostream VecOS(Code);
getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups(),
STI);
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().getMCLineTableSymbols().empty() ||
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();
}