#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCMachOSymbolFlags.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetAsmBackend.h"
+
using namespace llvm;
namespace {
class MCMachOStreamer : public MCStreamer {
- /// SymbolFlags - We store the value for the 'desc' symbol field in the lowest
- /// 16 bits of the implementation defined flags.
- enum SymbolFlags { // See <mach-o/nlist.h>.
- SF_DescFlagsMask = 0xFFFF,
-
- // Reference type flags.
- SF_ReferenceTypeMask = 0x0007,
- SF_ReferenceTypeUndefinedNonLazy = 0x0000,
- SF_ReferenceTypeUndefinedLazy = 0x0001,
- SF_ReferenceTypeDefined = 0x0002,
- SF_ReferenceTypePrivateDefined = 0x0003,
- SF_ReferenceTypePrivateUndefinedNonLazy = 0x0004,
- SF_ReferenceTypePrivateUndefinedLazy = 0x0005,
-
- // Other 'desc' flags.
- SF_NoDeadStrip = 0x0020,
- SF_WeakReference = 0x0040,
- SF_WeakDefinition = 0x0080
- };
private:
MCAssembler Assembler;
- MCCodeEmitter *Emitter;
MCSectionData *CurSectionData;
+ /// Track the current atom for each section.
+ DenseMap<const MCSectionData*, MCSymbolData*> CurrentAtomMap;
+
private:
MCFragment *getCurrentFragment() const {
assert(CurSectionData && "No current section!");
return 0;
}
+ /// Get a data fragment to write into, creating a new one if the current
+ /// fragment is not a data fragment.
+ MCDataFragment *getOrCreateDataFragment() const {
+ MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
+ if (!F)
+ F = createDataFragment();
+ return F;
+ }
+
+ /// Create a new data fragment in the current section.
+ MCDataFragment *createDataFragment() const {
+ MCDataFragment *DF = new MCDataFragment(CurSectionData);
+ DF->setAtom(CurrentAtomMap.lookup(CurSectionData));
+ return DF;
+ }
+
public:
MCMachOStreamer(MCContext &Context, TargetAsmBackend &TAB,
raw_ostream &_OS, MCCodeEmitter *_Emitter)
- : MCStreamer(Context), Assembler(Context, TAB, _OS), Emitter(_Emitter),
+ : MCStreamer(Context), Assembler(Context, TAB, *_Emitter, _OS),
CurSectionData(0) {}
~MCMachOStreamer() {}
+ MCAssembler &getAssembler() { return Assembler; }
+
const MCExpr *AddValueSymbols(const MCExpr *Value) {
switch (Value->getKind()) {
case MCExpr::Target: assert(0 && "Can't handle target exprs yet!");
virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment);
+ virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {
+ assert(0 && "macho doesn't support this directive");
+ }
+ virtual void EmitCOFFSymbolStorageClass(int StorageClass) {
+ assert(0 && "macho doesn't support this directive");
+ }
+ virtual void EmitCOFFSymbolType(int Type) {
+ assert(0 && "macho doesn't support this directive");
+ }
+ virtual void EndCOFFSymbolDef() {
+ assert(0 && "macho doesn't support this directive");
+ }
virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
assert(0 && "macho doesn't support this directive");
}
void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
-
- // FIXME: We should also use offsets into Fill fragments.
- MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
- if (!F)
- F = new MCDataFragment(CurSectionData);
+ assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
+ assert(CurSection && "Cannot emit before setting section!");
MCSymbolData &SD = Assembler.getOrCreateSymbolData(*Symbol);
+
+ // Update the current atom map, if necessary.
+ bool MustCreateFragment = false;
+ if (Assembler.isSymbolLinkerVisible(&SD)) {
+ CurrentAtomMap[CurSectionData] = &SD;
+
+ // We have to create a new fragment, fragments cannot span atoms.
+ MustCreateFragment = true;
+ }
+
+ // 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 =
+ MustCreateFragment ? createDataFragment() : getOrCreateDataFragment();
assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
SD.setFragment(F);
SD.setOffset(F->getContents().size());
}
void MCMachOStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
- // Only absolute symbols can be redefined.
- assert((Symbol->isUndefined() || Symbol->isAbsolute()) &&
- "Cannot define a symbol twice!");
-
// FIXME: Lift context changes into super class.
- // FIXME: Set associated section.
- Symbol->setValue(Value);
+ Symbol->setVariableValue(AddValueSymbols(Value));
}
void MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
MCFragment *F = new MCZeroFillFragment(Size, ByteAlignment, &SectData);
SD.setFragment(F);
+ if (Assembler.isSymbolLinkerVisible(&SD))
+ F->setAtom(&SD);
Symbol->setSection(*Section);
}
void MCMachOStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
- MCDataFragment *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
- if (!DF)
- DF = new MCDataFragment(CurSectionData);
- DF->getContents().append(Data.begin(), Data.end());
+ getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
}
void MCMachOStreamer::EmitValue(const MCExpr *Value, unsigned Size,
unsigned AddrSpace) {
- MCDataFragment *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
- if (!DF)
- DF = new MCDataFragment(CurSectionData);
+ MCDataFragment *DF = getOrCreateDataFragment();
// Avoid fixups when possible.
int64_t AbsValue;
for (unsigned i = 0; i != Size; ++i)
DF->getContents().push_back(uint8_t(AbsValue >> (i * 8)));
} else {
- DF->getFixups().push_back(MCAsmFixup(DF->getContents().size(),
- *AddValueSymbols(Value),
- MCFixup::getKindForSize(Size)));
+ DF->addFixup(MCAsmFixup(DF->getContents().size(), *AddValueSymbols(Value),
+ MCFixup::getKindForSize(Size)));
DF->getContents().resize(DF->getContents().size() + Size, 0);
}
}
unsigned MaxBytesToEmit) {
if (MaxBytesToEmit == 0)
MaxBytesToEmit = ByteAlignment;
- new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
- false /* EmitNops */, CurSectionData);
+ MCFragment *F = new MCAlignFragment(ByteAlignment, Value, ValueSize,
+ MaxBytesToEmit, /*EmitNops=*/false,
+ CurSectionData);
+ F->setAtom(CurrentAtomMap.lookup(CurSectionData));
// Update the maximum alignment on the current section if necessary.
if (ByteAlignment > CurSectionData->getAlignment())
unsigned MaxBytesToEmit) {
if (MaxBytesToEmit == 0)
MaxBytesToEmit = ByteAlignment;
- // FIXME the 0x90 is the default x86 1 byte nop opcode.
- new MCAlignFragment(ByteAlignment, 0x90, 1, MaxBytesToEmit,
- true /* EmitNops */, CurSectionData);
+ MCFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
+ /*EmitNops=*/true, CurSectionData);
+ F->setAtom(CurrentAtomMap.lookup(CurSectionData));
// Update the maximum alignment on the current section if necessary.
if (ByteAlignment > CurSectionData->getAlignment())
void MCMachOStreamer::EmitValueToOffset(const MCExpr *Offset,
unsigned char Value) {
- new MCOrgFragment(*Offset, Value, CurSectionData);
+ MCFragment *F = new MCOrgFragment(*Offset, Value, CurSectionData);
+ F->setAtom(CurrentAtomMap.lookup(CurSectionData));
}
void MCMachOStreamer::EmitInstruction(const MCInst &Inst) {
if (Inst.getOperand(i).isExpr())
AddValueSymbols(Inst.getOperand(i).getExpr());
- if (!Emitter)
- llvm_unreachable("no code emitter available!");
-
CurSectionData->setHasInstructions(true);
+ // FIXME-PERF: Common case is that we don't need to relax, encode directly
+ // onto the data fragments buffers.
+
SmallVector<MCFixup, 4> Fixups;
SmallString<256> Code;
raw_svector_ostream VecOS(Code);
- Emitter->EncodeInstruction(Inst, VecOS, Fixups);
+ Assembler.getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
VecOS.flush();
- // Add the fixups and data.
- MCDataFragment *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
- if (!DF)
- DF = new MCDataFragment(CurSectionData);
+ // FIXME: Eliminate this copy.
+ SmallVector<MCAsmFixup, 4> AsmFixups;
for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
MCFixup &F = Fixups[i];
- DF->getFixups().push_back(MCAsmFixup(DF->getContents().size()+F.getOffset(),
- *F.getValue(),
- F.getKind()));
+ AsmFixups.push_back(MCAsmFixup(F.getOffset(), *F.getValue(),
+ F.getKind()));
+ }
+
+ // See if we might need to relax this instruction, if so it needs its own
+ // fragment.
+ //
+ // FIXME-PERF: Support target hook to do a fast path that avoids the encoder,
+ // when we can immediately tell that we will get something which might need
+ // relaxation (and compute its size).
+ //
+ // FIXME-PERF: We should also be smart about immediately relaxing instructions
+ // which we can already show will never possibly fit (we can also do a very
+ // good job of this before we do the first relaxation pass, because we have
+ // total knowledge about undefined symbols at that point). Even now, though,
+ // we can do a decent job, especially on Darwin where scattering means that we
+ // are going to often know that we can never fully resolve a fixup.
+ if (Assembler.getBackend().MayNeedRelaxation(Inst, AsmFixups)) {
+ MCInstFragment *IF = new MCInstFragment(Inst, CurSectionData);
+ IF->setAtom(CurrentAtomMap.lookup(CurSectionData));
+
+ // Add the fixups and data.
+ //
+ // FIXME: Revisit this design decision when relaxation is done, we may be
+ // able to get away with not storing any extra data in the MCInst.
+ IF->getCode() = Code;
+ IF->getFixups() = AsmFixups;
+
+ return;
+ }
+
+ // Add the fixups and data.
+ MCDataFragment *DF = getOrCreateDataFragment();
+ for (unsigned i = 0, e = AsmFixups.size(); i != e; ++i) {
+ AsmFixups[i].Offset += DF->getContents().size();
+ DF->addFixup(AsmFixups[i]);
}
DF->getContents().append(Code.begin(), Code.end());
}
}
MCStreamer *llvm::createMachOStreamer(MCContext &Context, TargetAsmBackend &TAB,
- raw_ostream &OS, MCCodeEmitter *CE) {
- return new MCMachOStreamer(Context, TAB, OS, CE);
+ raw_ostream &OS, MCCodeEmitter *CE,
+ bool RelaxAll) {
+ MCMachOStreamer *S = new MCMachOStreamer(Context, TAB, OS, CE);
+ if (RelaxAll)
+ S->getAssembler().setRelaxAll(true);
+ return S;
}
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