MCMachOStreamer.cpp [plain text]
#include "llvm/MC/MCStreamer.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/MC/MCAsmBackend.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/MCInst.h"
#include "llvm/MC/MCLinkerOptimizationHint.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCObjectStreamer.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCSymbolMachO.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
namespace {
class MCMachOStreamer : public MCObjectStreamer {
private:
bool LabelSections;
bool DWARFMustBeAtTheEnd;
bool CreatedADWARFSection;
DenseMap<const MCSection*, bool> HasSectionLabel;
void EmitInstToData(const MCInst &Inst, const MCSubtargetInfo &STI) override;
void EmitDataRegion(DataRegionData::KindTy Kind);
void EmitDataRegionEnd();
public:
MCMachOStreamer(MCContext &Context, MCAsmBackend &MAB, raw_pwrite_stream &OS,
MCCodeEmitter *Emitter, bool DWARFMustBeAtTheEnd, bool label)
: MCObjectStreamer(Context, MAB, OS, Emitter), LabelSections(label),
DWARFMustBeAtTheEnd(DWARFMustBeAtTheEnd), CreatedADWARFSection(false) {}
void reset() override {
CreatedADWARFSection = false;
HasSectionLabel.clear();
MCObjectStreamer::reset();
}
void ChangeSection(MCSection *Sect, const MCExpr *Subsect) override;
void EmitLabel(MCSymbol *Symbol) override;
void EmitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol) override;
void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
void EmitLinkerOptions(ArrayRef<std::string> Options) override;
void EmitDataRegion(MCDataRegionType Kind) override;
void EmitVersionMin(MCVersionMinType Kind, unsigned Major,
unsigned Minor, unsigned Update) override;
void EmitThumbFunc(MCSymbol *Func) override;
bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) override;
void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) override;
void BeginCOFFSymbolDef(const MCSymbol *Symbol) override {
llvm_unreachable("macho doesn't support this directive");
}
void EmitCOFFSymbolStorageClass(int StorageClass) override {
llvm_unreachable("macho doesn't support this directive");
}
void EmitCOFFSymbolType(int Type) override {
llvm_unreachable("macho doesn't support this directive");
}
void EndCOFFSymbolDef() override {
llvm_unreachable("macho doesn't support this directive");
}
void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) override;
void EmitZerofill(MCSection *Section, MCSymbol *Symbol = nullptr,
uint64_t Size = 0, unsigned ByteAlignment = 0) override;
void EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment = 0) override;
void EmitFileDirective(StringRef Filename) override {
}
void EmitIdent(StringRef IdentString) override {
llvm_unreachable("macho doesn't support this directive");
}
void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) override {
getAssembler().getLOHContainer().addDirective(Kind, Args);
}
void FinishImpl() override;
};
}
static bool canGoAfterDWARF(const MCSectionMachO &MSec) {
StringRef SegName = MSec.getSegmentName();
StringRef SecName = MSec.getSectionName();
if (SegName == "__LD" && SecName == "__compact_unwind")
return true;
if (SegName == "__IMPORT") {
if (SecName == "__jump_table")
return true;
if (SecName == "__pointers")
return true;
}
if (SegName == "__TEXT" && SecName == "__eh_frame")
return true;
if (SegName == "__DATA" && SecName == "__nl_symbol_ptr")
return true;
return false;
}
void MCMachOStreamer::ChangeSection(MCSection *Section,
const MCExpr *Subsection) {
bool Created = MCObjectStreamer::changeSectionImpl(Section, Subsection);
const MCSectionMachO &MSec = *cast<MCSectionMachO>(Section);
StringRef SegName = MSec.getSegmentName();
if (SegName == "__DWARF")
CreatedADWARFSection = true;
else if (Created && DWARFMustBeAtTheEnd && !canGoAfterDWARF(MSec))
assert(!CreatedADWARFSection && "Creating regular section after DWARF");
if (LabelSections && !HasSectionLabel[Section] &&
!Section->getBeginSymbol()) {
MCSymbol *Label = getContext().createLinkerPrivateTempSymbol();
Section->setBeginSymbol(Label);
HasSectionLabel[Section] = true;
}
}
void MCMachOStreamer::EmitEHSymAttributes(const MCSymbol *Symbol,
MCSymbol *EHSymbol) {
getAssembler().registerSymbol(*Symbol);
if (Symbol->isExternal())
EmitSymbolAttribute(EHSymbol, MCSA_Global);
if (cast<MCSymbolMachO>(Symbol)->isWeakDefinition())
EmitSymbolAttribute(EHSymbol, MCSA_WeakDefinition);
if (Symbol->isPrivateExtern())
EmitSymbolAttribute(EHSymbol, MCSA_PrivateExtern);
}
void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
if (getAssembler().isSymbolLinkerVisible(*Symbol))
insert(new MCDataFragment());
MCObjectStreamer::EmitLabel(Symbol);
cast<MCSymbolMachO>(Symbol)->clearReferenceType();
}
void MCMachOStreamer::EmitDataRegion(DataRegionData::KindTy Kind) {
if (!getAssembler().getBackend().hasDataInCodeSupport())
return;
MCSymbol *Start = getContext().createTempSymbol();
EmitLabel(Start);
DataRegionData Data = { Kind, Start, nullptr };
std::vector<DataRegionData> &Regions = getAssembler().getDataRegions();
Regions.push_back(Data);
}
void MCMachOStreamer::EmitDataRegionEnd() {
if (!getAssembler().getBackend().hasDataInCodeSupport())
return;
std::vector<DataRegionData> &Regions = getAssembler().getDataRegions();
assert(!Regions.empty() && "Mismatched .end_data_region!");
DataRegionData &Data = Regions.back();
assert(!Data.End && "Mismatched .end_data_region!");
Data.End = getContext().createTempSymbol();
EmitLabel(Data.End);
}
void MCMachOStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
getAssembler().getBackend().handleAssemblerFlag(Flag);
switch (Flag) {
case MCAF_SyntaxUnified: return; case MCAF_Code16: return; case MCAF_Code32: return; case MCAF_Code64: return; case MCAF_SubsectionsViaSymbols:
getAssembler().setSubsectionsViaSymbols(true);
return;
}
}
void MCMachOStreamer::EmitLinkerOptions(ArrayRef<std::string> Options) {
getAssembler().getLinkerOptions().push_back(Options);
}
void MCMachOStreamer::EmitDataRegion(MCDataRegionType Kind) {
switch (Kind) {
case MCDR_DataRegion:
EmitDataRegion(DataRegionData::Data);
return;
case MCDR_DataRegionJT8:
EmitDataRegion(DataRegionData::JumpTable8);
return;
case MCDR_DataRegionJT16:
EmitDataRegion(DataRegionData::JumpTable16);
return;
case MCDR_DataRegionJT32:
EmitDataRegion(DataRegionData::JumpTable32);
return;
case MCDR_DataRegionEnd:
EmitDataRegionEnd();
return;
}
}
void MCMachOStreamer::EmitVersionMin(MCVersionMinType Kind, unsigned Major,
unsigned Minor, unsigned Update) {
getAssembler().setVersionMinInfo(Kind, Major, Minor, Update);
}
void MCMachOStreamer::EmitThumbFunc(MCSymbol *Symbol) {
getAssembler().setIsThumbFunc(Symbol);
cast<MCSymbolMachO>(Symbol)->setThumbFunc();
}
bool MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Sym,
MCSymbolAttr Attribute) {
MCSymbolMachO *Symbol = cast<MCSymbolMachO>(Sym);
if (Attribute == MCSA_IndirectSymbol) {
IndirectSymbolData ISD;
ISD.Symbol = Symbol;
ISD.Section = getCurrentSectionOnly();
getAssembler().getIndirectSymbols().push_back(ISD);
return true;
}
getAssembler().registerSymbol(*Symbol);
switch (Attribute) {
case MCSA_Invalid:
case MCSA_ELF_TypeFunction:
case MCSA_ELF_TypeIndFunction:
case MCSA_ELF_TypeObject:
case MCSA_ELF_TypeTLS:
case MCSA_ELF_TypeCommon:
case MCSA_ELF_TypeNoType:
case MCSA_ELF_TypeGnuUniqueObject:
case MCSA_Hidden:
case MCSA_IndirectSymbol:
case MCSA_Internal:
case MCSA_Protected:
case MCSA_Weak:
case MCSA_Local:
return false;
case MCSA_Global:
Symbol->setExternal(true);
Symbol->setReferenceTypeUndefinedLazy(false);
break;
case MCSA_LazyReference:
Symbol->setNoDeadStrip();
if (Symbol->isUndefined())
Symbol->setReferenceTypeUndefinedLazy(true);
break;
case MCSA_Reference:
case MCSA_NoDeadStrip:
Symbol->setNoDeadStrip();
break;
case MCSA_SymbolResolver:
Symbol->setSymbolResolver();
break;
case MCSA_AltEntry:
Symbol->setAltEntry();
break;
case MCSA_PrivateExtern:
Symbol->setExternal(true);
Symbol->setPrivateExtern(true);
break;
case MCSA_WeakReference:
if (Symbol->isUndefined())
Symbol->setWeakReference();
break;
case MCSA_WeakDefinition:
Symbol->setWeakDefinition();
break;
case MCSA_WeakDefAutoPrivate:
Symbol->setWeakDefinition();
Symbol->setWeakReference();
break;
}
return true;
}
void MCMachOStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
getAssembler().registerSymbol(*Symbol);
cast<MCSymbolMachO>(Symbol)->setDesc(DescValue);
}
void MCMachOStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) {
assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
getAssembler().registerSymbol(*Symbol);
Symbol->setExternal(true);
Symbol->setCommon(Size, ByteAlignment);
}
void MCMachOStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) {
return EmitZerofill(getContext().getObjectFileInfo()->getDataBSSSection(),
Symbol, Size, ByteAlignment);
}
void MCMachOStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment) {
getAssembler().registerSection(*Section);
if (!Symbol)
return;
assert(Section->isVirtualSection() && "Section does not have zerofill type!");
assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
getAssembler().registerSymbol(*Symbol);
if (ByteAlignment != 1)
new MCAlignFragment(ByteAlignment, 0, 0, ByteAlignment, Section);
MCFragment *F = new MCFillFragment(0, Size, Section);
Symbol->setFragment(F);
if (ByteAlignment > Section->getAlignment())
Section->setAlignment(ByteAlignment);
}
void MCMachOStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
uint64_t Size, unsigned ByteAlignment) {
EmitZerofill(Section, Symbol, Size, ByteAlignment);
return;
}
void MCMachOStreamer::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);
for (MCFixup &Fixup : Fixups) {
Fixup.setOffset(Fixup.getOffset() + DF->getContents().size());
DF->getFixups().push_back(Fixup);
}
DF->getContents().append(Code.begin(), Code.end());
}
void MCMachOStreamer::FinishImpl() {
EmitFrames(&getAssembler().getBackend());
DenseMap<const MCFragment *, const MCSymbol *> DefiningSymbolMap;
for (const MCSymbol &Symbol : getAssembler().symbols()) {
if (getAssembler().isSymbolLinkerVisible(Symbol) && Symbol.isInSection() &&
!Symbol.isVariable()) {
assert(Symbol.getOffset() == 0 &&
"Invalid offset in atom defining symbol!");
DefiningSymbolMap[Symbol.getFragment()] = &Symbol;
}
}
for (MCSection &Sec : getAssembler()) {
const MCSymbol *CurrentAtom = nullptr;
for (MCFragment &Frag : Sec) {
if (const MCSymbol *Symbol = DefiningSymbolMap.lookup(&Frag))
CurrentAtom = Symbol;
Frag.setAtom(CurrentAtom);
}
}
this->MCObjectStreamer::FinishImpl();
}
MCStreamer *llvm::createMachOStreamer(MCContext &Context, MCAsmBackend &MAB,
raw_pwrite_stream &OS, MCCodeEmitter *CE,
bool RelaxAll, bool DWARFMustBeAtTheEnd,
bool LabelSections) {
MCMachOStreamer *S = new MCMachOStreamer(Context, MAB, OS, CE,
DWARFMustBeAtTheEnd, LabelSections);
const Triple &TT = Context.getObjectFileInfo()->getTargetTriple();
if (TT.isOSDarwin()) {
unsigned Major, Minor, Update;
TT.getOSVersion(Major, Minor, Update);
if (Major) {
MCVersionMinType VersionType;
if (TT.isWatchOS())
VersionType = MCVM_WatchOSVersionMin;
else if (TT.isTvOS())
VersionType = MCVM_TvOSVersionMin;
else if (TT.isMacOSX())
VersionType = MCVM_OSXVersionMin;
else {
assert(TT.isiOS() && "Must only be iOS platform left");
VersionType = MCVM_IOSVersionMin;
}
S->EmitVersionMin(VersionType, Major, Minor, Update);
}
}
if (RelaxAll)
S->getAssembler().setRelaxAll(true);
return S;
}