C++ MCSymbol::getName方法代码示例

/// Emit extern decls for functions imported from other modules, and emit
/// global declarations for function defined in this module and which are
/// available to other modules.
///
void PIC16AsmPrinter::EmitFunctionDecls(Module &M) {
 // Emit declarations for external functions.
  O <<"\n"<<MAI->getCommentString() << "Function Declarations - BEGIN." <<"\n";
  for (Module::iterator I = M.begin(), E = M.end(); I != E; I++) {
    if (I->isIntrinsic() || I->getName() == "@abort")
      continue;
    
    if (!I->isDeclaration() && !I->hasExternalLinkage())
      continue;

    MCSymbol *Sym = Mang->getSymbol(I);
    
    // Do not emit memcpy, memset, and memmove here.
    // Calls to these routines can be generated in two ways,
    // 1. User calling the standard lib function
    // 2. Codegen generating these calls for llvm intrinsics.
    // In the first case a prototype is alread availale, while in
    // second case the call is via and externalsym and the prototype is missing.
    // So declarations for these are currently always getting printing by
    // tracking both kind of references in printInstrunction.
    if (I->isDeclaration() && PAN::isMemIntrinsic(Sym->getName())) continue;

    const char *directive = I->isDeclaration() ? MAI->getExternDirective() :
                                                 MAI->getGlobalDirective();
      
    O << directive << Sym->getName() << "\n";
    O << directive << PAN::getRetvalLabel(Sym->getName()) << "\n";
    O << directive << PAN::getArgsLabel(Sym->getName()) << "\n";
  }

  O << MAI->getCommentString() << "Function Declarations - END." <<"\n";
}

const MCSection *TargetLoweringObjectFileCOFF::
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
                       Mangler *Mang, const TargetMachine &TM) const {

  // If this global is linkonce/weak and the target handles this by emitting it
  // into a 'uniqued' section name, create and return the section now.
  if (GV->isWeakForLinker()) {
    const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
    SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
    MCSymbol *Sym = Mang->getSymbol(GV);
    Name.append(Sym->getName().begin() + 1, Sym->getName().end());

    unsigned Characteristics = getCOFFSectionFlags(Kind);

    Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;

    return getContext().getCOFFSection(Name.str(), Characteristics,
                          COFF::IMAGE_COMDAT_SELECT_ANY, Kind);
  }

  if (Kind.isText())
    return getTextSection();

  if (Kind.isThreadLocal())
    return getTLSDataSection();

  return getDataSection();
}

void XCoreAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
  // Check to see if this is a special global used by LLVM, if so, emit it.
  if (!GV->hasInitializer() ||
      EmitSpecialLLVMGlobal(GV))
    return;

  const DataLayout *TD = TM.getDataLayout();
  OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(GV, Mang,TM));

  
  MCSymbol *GVSym = getSymbol(GV);
  const Constant *C = GV->getInitializer();
  unsigned Align = (unsigned)TD->getPreferredTypeAlignmentShift(C->getType());
  
  // Mark the start of the global
  getTargetStreamer().emitCCTopData(GVSym->getName());

  switch (GV->getLinkage()) {
  case GlobalValue::AppendingLinkage:
    report_fatal_error("AppendingLinkage is not supported by this target!");
  case GlobalValue::LinkOnceAnyLinkage:
  case GlobalValue::LinkOnceODRLinkage:
  case GlobalValue::WeakAnyLinkage:
  case GlobalValue::WeakODRLinkage:
  case GlobalValue::ExternalLinkage:
    emitArrayBound(GVSym, GV);
    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);

    // TODO Use COMDAT groups for LinkOnceLinkage
    if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage())
      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
    // FALL THROUGH
  case GlobalValue::InternalLinkage:
  case GlobalValue::PrivateLinkage:
    break;
  default:
    llvm_unreachable("Unknown linkage type!");
  }

  EmitAlignment(Align > 2 ? Align : 2, GV);
  
  if (GV->isThreadLocal()) {
    report_fatal_error("TLS is not supported by this target!");
  }
  unsigned Size = TD->getTypeAllocSize(C->getType());
  if (MAI->hasDotTypeDotSizeDirective()) {
    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
    OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
  }
  OutStreamer.EmitLabel(GVSym);
  
  EmitGlobalConstant(C);
  // The ABI requires that unsigned scalar types smaller than 32 bits
  // are padded to 32 bits.
  if (Size < 4)
    OutStreamer.EmitZeros(4 - Size);
  
  // Mark the end of the global
  getTargetStreamer().emitCCBottomData(GVSym->getName());
}

// printOperand - print operand of insn.
void PIC16AsmPrinter::printOperand(const MachineInstr *MI, int opNum) {
  const MachineOperand &MO = MI->getOperand(opNum);
  const Function *F = MI->getParent()->getParent()->getFunction();

  switch (MO.getType()) {
    case MachineOperand::MO_Register:
      {
        // For indirect load/store insns, the fsr name is printed as INDF.
        std::string RegName = getRegisterName(MO.getReg());
        if ((MI->getOpcode() == PIC16::load_indirect) ||
            (MI->getOpcode() == PIC16::store_indirect))
        {
          RegName.replace (0, 3, "INDF");
        }
        O << RegName;
      }
      return;

    case MachineOperand::MO_Immediate:
      O << (int)MO.getImm();
      return;

    case MachineOperand::MO_GlobalAddress: {
      MCSymbol *Sym = Mang->getSymbol(MO.getGlobal());
      // FIXME: currently we do not have a memcpy def coming in the module
      // by any chance, as we do not link in those as .bc lib. So these calls
      // are always external and it is safe to emit an extern.
      if (PAN::isMemIntrinsic(Sym->getName()))
        LibcallDecls.push_back(createESName(Sym->getName()));

      O << *Sym;
      break;
    }
    case MachineOperand::MO_ExternalSymbol: {
       const char *Sname = MO.getSymbolName();
       std::string Printname = Sname;

      // Intrinsic stuff needs to be renamed if we are printing IL fn. 
      if (PAN::isIntrinsicStuff(Printname)) {
        if (PAN::isISR(F->getSection())) {
          Printname = PAN::Rename(Sname);
        }
        // Record these decls, we need to print them in asm as extern.
        LibcallDecls.push_back(createESName(Printname));
      }

      O << Printname;
      break;
    }
    case MachineOperand::MO_MachineBasicBlock:
      O << *MO.getMBB()->getSymbol();
      return;

    default:
      llvm_unreachable(" Operand type not supported.");
  }
}

/// This hook allows targets to selectively decide not to emit the UsedDirective
/// for some symbols in llvm.used.
// FIXME: REMOVE this (rdar://7071300)
bool TargetLoweringObjectFileMachO::shouldEmitUsedDirectiveFor(
    const GlobalValue *GV, Mangler &Mang, TargetMachine &TM) const {
  // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
  if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
    // FIXME: ObjC metadata is currently emitted as internal symbols that have
    // \1L and \0l prefixes on them.  Fix them to be Private/LinkerPrivate and
    // this horrible hack can go away.
    MCSymbol *Sym = TM.getSymbol(GV, Mang);
    if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l')
      return false;
  }

  return true;
}

const MCSection *TargetLoweringObjectFileCOFF::
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
                       Mangler &Mang, const TargetMachine &TM) const {

  // If this global is linkonce/weak and the target handles this by emitting it
  // into a 'uniqued' section name, create and return the section now.
  if (GV->isWeakForLinker()) {
    const char *Name = getCOFFSectionNameForUniqueGlobal(Kind);
    unsigned Characteristics = getCOFFSectionFlags(Kind);

    Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
    MCSymbol *Sym = TM.getSymbol(GV, Mang);
    return getContext().getCOFFSection(Name, Characteristics,
                                       Kind, Sym->getName(),
                                       COFF::IMAGE_COMDAT_SELECT_ANY);
  }

  if (Kind.isText())
    return TextSection;

  if (Kind.isThreadLocal())
    return TLSDataSection;

  if (Kind.isReadOnly())
    return ReadOnlySection;

  if (Kind.isBSS())
    return BSSSection;

  return DataSection;
}

uint64_t MachObjectWriter::getSymbolAddress(const MCSymbol &S,
                                            const MCAsmLayout &Layout) const {
  // If this is a variable, then recursively evaluate now.
  if (S.isVariable()) {
    if (const MCConstantExpr *C =
          dyn_cast<const MCConstantExpr>(S.getVariableValue()))
      return C->getValue();

    MCValue Target;
    if (!S.getVariableValue()->evaluateAsRelocatable(Target, &Layout, nullptr))
      report_fatal_error("unable to evaluate offset for variable '" +
                         S.getName() + "'");

    // Verify that any used symbols are defined.
    if (Target.getSymA() && Target.getSymA()->getSymbol().isUndefined())
      report_fatal_error("unable to evaluate offset to undefined symbol '" +
                         Target.getSymA()->getSymbol().getName() + "'");
    if (Target.getSymB() && Target.getSymB()->getSymbol().isUndefined())
      report_fatal_error("unable to evaluate offset to undefined symbol '" +
                         Target.getSymB()->getSymbol().getName() + "'");

    uint64_t Address = Target.getConstant();
    if (Target.getSymA())
      Address += getSymbolAddress(Target.getSymA()->getSymbol(), Layout);
    if (Target.getSymB())
      Address += getSymbolAddress(Target.getSymB()->getSymbol(), Layout);
    return Address;
  }

  return getSectionAddress(S.getFragment()->getParent()) +
         Layout.getSymbolOffset(S);
}

void TargetLoweringObjectFileELF::emitPersonalityValue(MCStreamer &Streamer,
                                                       const TargetMachine &TM,
                                                       const MCSymbol *Sym) const {
  SmallString<64> NameData("DW.ref.");
  NameData += Sym->getName();
  MCSymbol *Label = getContext().GetOrCreateSymbol(NameData);
  Streamer.EmitSymbolAttribute(Label, MCSA_Hidden);
  Streamer.EmitSymbolAttribute(Label, MCSA_Weak);
  StringRef Prefix = ".data.";
  NameData.insert(NameData.begin(), Prefix.begin(), Prefix.end());
  unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
  const MCSection *Sec = getContext().getELFSection(NameData,
                                                    ELF::SHT_PROGBITS,
                                                    Flags,
                                                    SectionKind::getDataRel(),
                                                    0, Label->getName());
  unsigned Size = TM.getDataLayout()->getPointerSize(0);
  Streamer.SwitchSection(Sec);
  Streamer.EmitValueToAlignment(TM.getDataLayout()->getPointerABIAlignment(0));
  Streamer.EmitSymbolAttribute(Label, MCSA_ELF_TypeObject);
  const MCExpr *E = MCConstantExpr::Create(Size, getContext());
  Streamer.EmitELFSize(Label, E);
  Streamer.EmitLabel(Label);

  Streamer.EmitSymbolValue(Sym, Size);
}

const MCSection *TargetLoweringObjectFileCOFF::getExplicitSectionGlobal(
    const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
    const TargetMachine &TM) const {
  int Selection = 0;
  unsigned Characteristics = getCOFFSectionFlags(Kind);
  StringRef Name = GV->getSection();
  StringRef COMDATSymName = "";
  if ((GV->isWeakForLinker() || GV->hasComdat()) && !Kind.isCommon()) {
    Selection = getSelectionForCOFF(GV);
    const GlobalValue *ComdatGV;
    if (Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
      ComdatGV = getComdatGVForCOFF(GV);
    else
      ComdatGV = GV;

    if (!ComdatGV->hasPrivateLinkage()) {
      MCSymbol *Sym = TM.getSymbol(ComdatGV, Mang);
      COMDATSymName = Sym->getName();
      Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
    } else {
      Selection = 0;
    }
  }
  return getContext().getCOFFSection(Name,
                                     Characteristics,
                                     Kind,
                                     COMDATSymName,
                                     Selection);
}

static bool getSymbolOffsetImpl(const MCAsmLayout &Layout, const MCSymbol &S,
                                bool ReportError, uint64_t &Val) {
  if (!S.isVariable())
    return getLabelOffset(Layout, S, ReportError, Val);

  // If SD is a variable, evaluate it.
  MCValue Target;
  if (!S.getVariableValue()->evaluateAsValue(Target, Layout))
    report_fatal_error("unable to evaluate offset for variable '" +
                       S.getName() + "'");

  uint64_t Offset = Target.getConstant();

  const MCSymbolRefExpr *A = Target.getSymA();
  if (A) {
    uint64_t ValA;
    if (!getLabelOffset(Layout, A->getSymbol(), ReportError, ValA))
      return false;
    Offset += ValA;
  }

  const MCSymbolRefExpr *B = Target.getSymB();
  if (B) {
    uint64_t ValB;
    if (!getLabelOffset(Layout, B->getSymbol(), ReportError, ValB))
      return false;
    Offset -= ValB;
  }

  Val = Offset;
  return true;
}

void TargetLoweringObjectFileELF::emitPersonalityValue(MCStreamer &Streamer,
                                                       const TargetMachine &TM,
                                                       const MCSymbol *Sym) const {
  SmallString<64> NameData("DW.ref.");
  // @LOCALMOD-BEGIN
  // The dwarf section label should not include the version suffix.
  // Strip it off here.
  StringRef Name = Sym->getName();
  size_t atpos = Name.find("@");
  if (atpos != StringRef::npos)
    Name = Name.substr(0, atpos);
  // @LOCALMOD-END
  NameData += Name; // @LOCALMOD
  MCSymbol *Label = getContext().GetOrCreateSymbol(NameData);
  Streamer.EmitSymbolAttribute(Label, MCSA_Hidden);
  Streamer.EmitSymbolAttribute(Label, MCSA_Weak);
  StringRef Prefix = ".data.";
  NameData.insert(NameData.begin(), Prefix.begin(), Prefix.end());
  unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
  const MCSection *Sec = getContext().getELFSection(NameData,
                                                    ELF::SHT_PROGBITS,
                                                    Flags,
                                                    SectionKind::getDataRel(),
                                                    0, Label->getName());
  unsigned Size = TM.getDataLayout()->getPointerSize();
  Streamer.SwitchSection(Sec);
  Streamer.EmitValueToAlignment(TM.getDataLayout()->getPointerABIAlignment());
  Streamer.EmitSymbolAttribute(Label, MCSA_ELF_TypeObject);
  const MCExpr *E = MCConstantExpr::Create(Size, getContext());
  Streamer.EmitELFSize(Label, E);
  Streamer.EmitLabel(Label);

  Streamer.EmitSymbolValue(Sym, Size);
}

MCSection *TargetLoweringObjectFileCOFF::getSectionForJumpTable(
    const Function &F, const TargetMachine &TM) const {
  // If the function can be removed, produce a unique section so that
  // the table doesn't prevent the removal.
  const Comdat *C = F.getComdat();
  bool EmitUniqueSection = TM.getFunctionSections() || C;
  if (!EmitUniqueSection)
    return ReadOnlySection;

  // FIXME: we should produce a symbol for F instead.
  if (F.hasPrivateLinkage())
    return ReadOnlySection;

  MCSymbol *Sym = TM.getSymbol(&F);
  StringRef COMDATSymName = Sym->getName();

  SectionKind Kind = SectionKind::getReadOnly();
  const char *Name = getCOFFSectionNameForUniqueGlobal(Kind);
  unsigned Characteristics = getCOFFSectionFlags(Kind, TM);
  Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
  unsigned UniqueID = NextUniqueID++;

  return getContext().getCOFFSection(Name, Characteristics, Kind, COMDATSymName,
                                     COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE, UniqueID);
}

MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
                                         unsigned Characteristics,
                                         SectionKind Kind,
                                         StringRef COMDATSymName, int Selection,
                                         const char *BeginSymName) {
  MCSymbol *COMDATSymbol = nullptr;
  if (!COMDATSymName.empty()) {
    COMDATSymbol = getOrCreateSymbol(COMDATSymName);
    COMDATSymName = COMDATSymbol->getName();
  }

  // Do the lookup, if we have a hit, return it.
  COFFSectionKey T{Section, COMDATSymName, Selection};
  auto IterBool = COFFUniquingMap.insert(std::make_pair(T, nullptr));
  auto Iter = IterBool.first;
  if (!IterBool.second)
    return Iter->second;

  MCSymbol *Begin = nullptr;
  if (BeginSymName)
    Begin = createTempSymbol(BeginSymName, false);

  StringRef CachedName = Iter->first.SectionName;
  MCSectionCOFF *Result = new (COFFAllocator.Allocate()) MCSectionCOFF(
      CachedName, Characteristics, COMDATSymbol, Selection, Kind, Begin);

  Iter->second = Result;
  return Result;
}

MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal(
    const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
    const TargetMachine &TM) const {
  // If we have -ffunction-sections then we should emit the global value to a
  // uniqued section specifically for it.
  bool EmitUniquedSection;
  if (Kind.isText())
    EmitUniquedSection = TM.getFunctionSections();
  else
    EmitUniquedSection = TM.getDataSections();

  if ((EmitUniquedSection && !Kind.isCommon()) || GV->hasComdat()) {
    const char *Name = getCOFFSectionNameForUniqueGlobal(Kind);
    unsigned Characteristics = getCOFFSectionFlags(Kind);

    Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
    int Selection = getSelectionForCOFF(GV);
    if (!Selection)
      Selection = COFF::IMAGE_COMDAT_SELECT_NODUPLICATES;
    const GlobalValue *ComdatGV;
    if (GV->hasComdat())
      ComdatGV = getComdatGVForCOFF(GV);
    else
      ComdatGV = GV;

    unsigned UniqueID = MCContext::GenericSectionID;
    if (EmitUniquedSection)
      UniqueID = NextUniqueID++;

    if (!ComdatGV->hasPrivateLinkage()) {
      MCSymbol *Sym = TM.getSymbol(ComdatGV, Mang);
      StringRef COMDATSymName = Sym->getName();
      return getContext().getCOFFSection(Name, Characteristics, Kind,
                                         COMDATSymName, Selection, UniqueID);
    } else {
      SmallString<256> TmpData;
      Mang.getNameWithPrefix(TmpData, GV, /*CannotUsePrivateLabel=*/true);
      return getContext().getCOFFSection(Name, Characteristics, Kind, TmpData,
                                         Selection, UniqueID);
    }
  }

  if (Kind.isText())
    return TextSection;

  if (Kind.isThreadLocal())
    return TLSDataSection;

  if (Kind.isReadOnly() || Kind.isReadOnlyWithRel())
    return ReadOnlySection;

  // Note: we claim that common symbols are put in BSSSection, but they are
  // really emitted with the magic .comm directive, which creates a symbol table
  // entry but not a section.
  if (Kind.isBSS() || Kind.isCommon())
    return BSSSection;

  return DataSection;
}

/// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
/// not to emit the UsedDirective for some symbols in llvm.used.
// FIXME: REMOVE this (rdar://7071300)
bool TargetLoweringObjectFileMachO::
shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
  /// On Darwin, internally linked data beginning with "L" or "l" does not have
  /// the directive emitted (this occurs in ObjC metadata).
  if (!GV) return false;

  // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
  if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
    // FIXME: ObjC metadata is currently emitted as internal symbols that have
    // \1L and \0l prefixes on them.  Fix them to be Private/LinkerPrivate and
    // this horrible hack can go away.
    MCSymbol *Sym = Mang->getSymbol(GV);
    if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l')
      return false;
  }

  return true;
}