C++ Mangler::getNameWithPrefix方法代码示例

void TargetLoweringObjectFileCOFF::emitLinkerFlagsForGlobal(
    raw_ostream &OS, const GlobalValue *GV, const Mangler &Mang) const {
  if (!GV->hasDLLExportStorageClass() || GV->isDeclaration())
    return;

  const Triple &TT = getTargetTriple();

  if (TT.isKnownWindowsMSVCEnvironment())
    OS << " /EXPORT:";
  else
    OS << " -export:";

  if (TT.isWindowsGNUEnvironment() || TT.isWindowsCygwinEnvironment()) {
    std::string Flag;
    raw_string_ostream FlagOS(Flag);
    Mang.getNameWithPrefix(FlagOS, GV, false);
    FlagOS.flush();
    if (Flag[0] == GV->getParent()->getDataLayout().getGlobalPrefix())
      OS << Flag.substr(1);
    else
      OS << Flag;
  } else {
    Mang.getNameWithPrefix(OS, GV, false);
  }

  if (!GV->getValueType()->isFunctionTy()) {
    if (TT.isKnownWindowsMSVCEnvironment())
      OS << ",DATA";
    else
      OS << ",data";
  }
}

void LTOCodeGenerator::
applyRestriction(GlobalValue &GV,
                 const ArrayRef<StringRef> &Libcalls,
                 std::vector<const char*> &MustPreserveList,
                 SmallPtrSet<GlobalValue*, 8> &AsmUsed,
                 Mangler &Mangler) {
  SmallString<64> Buffer;
  Mangler.getNameWithPrefix(Buffer, &GV);

  if (GV.isDeclaration())
    return;
  if (MustPreserveSymbols.count(Buffer))
    MustPreserveList.push_back(GV.getName().data());
  if (AsmUndefinedRefs.count(Buffer))
    AsmUsed.insert(&GV);

  // Conservatively append user-supplied runtime library functions to
  // llvm.compiler.used.  These could be internalized and deleted by
  // optimizations like -globalopt, causing problems when later optimizations
  // add new library calls (e.g., llvm.memset => memset and printf => puts).
  // Leave it to the linker to remove any dead code (e.g. with -dead_strip).
  if (isa<Function>(GV) &&
      std::binary_search(Libcalls.begin(), Libcalls.end(), GV.getName()))
    AsmUsed.insert(&GV);
}

std::string ExecutionEngine::getMangledName(const GlobalValue *GV) {
  MutexGuard locked(lock);
  Mangler Mang;
  SmallString<128> FullName;
  Mang.getNameWithPrefix(FullName, GV, false);
  return FullName.str();
}

void llvm::emitLinkerFlagsForUsedCOFF(raw_ostream &OS, const GlobalValue *GV,
                                      const Triple &T, Mangler &M) {
  if (!T.isKnownWindowsMSVCEnvironment())
    return;

  OS << " /INCLUDE:";
  M.getNameWithPrefix(OS, GV, false);
}

void TargetLoweringObjectFileMachO::getNameWithPrefix(
    SmallVectorImpl<char> &OutName, const GlobalValue *GV, Mangler &Mang,
    const TargetMachine &TM) const {
  SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
  const MCSection *TheSection = SectionForGlobal(GV, GVKind, Mang, TM);
  bool CannotUsePrivateLabel =
      !canUsePrivateLabel(*TM.getMCAsmInfo(), *TheSection);
  Mang.getNameWithPrefix(OutName, GV, CannotUsePrivateLabel);
}

void TargetLoweringObjectFileCOFF::getNameWithPrefix(
    SmallVectorImpl<char> &OutName, const GlobalValue *GV,
    bool CannotUsePrivateLabel, Mangler &Mang, const TargetMachine &TM) const {
  if (GV->hasPrivateLinkage() &&
      ((isa<Function>(GV) && TM.getFunctionSections()) ||
       (isa<GlobalVariable>(GV) && TM.getDataSections())))
    CannotUsePrivateLabel = true;

  Mang.getNameWithPrefix(OutName, GV, CannotUsePrivateLabel);
}

	std::string mangle(const GlobalValue *GV) {
		std::string MangledName;
		{
			Mangler Mang;

			raw_string_ostream MangledNameStream(MangledName);
			Mang.getNameWithPrefix(MangledNameStream, GV, false);
		}
		return MangledName;
	}

void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name,
                                      const GlobalValue *GV, Mangler &Mang,
                                      bool MayAlwaysUsePrivate) const {
  if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
    // Simple case: If GV is not private, it is not important to find out if
    // private labels are legal in this case or not.
    Mang.getNameWithPrefix(Name, GV, false);
    return;
  }
  const TargetLoweringObjectFile *TLOF = getObjFileLowering();
  TLOF->getNameWithPrefix(Name, GV, Mang, *this);
}

void LTOCodeGenerator::applyScopeRestrictions() {
  if (ScopeRestrictionsDone)
    return;

  // Declare a callback for the internalize pass that will ask for every
  // candidate GlobalValue if it can be internalized or not.
  Mangler Mang;
  SmallString<64> MangledName;
  auto mustPreserveGV = [&](const GlobalValue &GV) -> bool {
    // Unnamed globals can't be mangled, but they can't be preserved either.
    if (!GV.hasName())
      return false;

    // Need to mangle the GV as the "MustPreserveSymbols" StringSet is filled
    // with the linker supplied name, which on Darwin includes a leading
    // underscore.
    MangledName.clear();
    MangledName.reserve(GV.getName().size() + 1);
    Mang.getNameWithPrefix(MangledName, &GV, /*CannotUsePrivateLabel=*/false);
    return MustPreserveSymbols.count(MangledName);
  };

  // Preserve linkonce value on linker request
  preserveDiscardableGVs(*MergedModule, mustPreserveGV);

  if (!ShouldInternalize)
    return;

  if (ShouldRestoreGlobalsLinkage) {
    // Record the linkage type of non-local symbols so they can be restored
    // prior
    // to module splitting.
    auto RecordLinkage = [&](const GlobalValue &GV) {
      if (!GV.hasAvailableExternallyLinkage() && !GV.hasLocalLinkage() &&
          GV.hasName())
        ExternalSymbols.insert(std::make_pair(GV.getName(), GV.getLinkage()));
    };
    for (auto &GV : *MergedModule)
      RecordLinkage(GV);
    for (auto &GV : MergedModule->globals())
      RecordLinkage(GV);
    for (auto &GV : MergedModule->aliases())
      RecordLinkage(GV);
  }

  // Update the llvm.compiler_used globals to force preserving libcalls and
  // symbols referenced from asm
  updateCompilerUsed(*MergedModule, *TargetMach, AsmUndefinedRefs);

  internalizeModule(*MergedModule, mustPreserveGV);

  ScopeRestrictionsDone = true;
}

void LTOCodeGenerator::
applyRestriction(GlobalValue &GV,
                 std::vector<const char*> &mustPreserveList,
                 SmallPtrSet<GlobalValue*, 8> &asmUsed,
                 Mangler &mangler) {
  SmallString<64> Buffer;
  mangler.getNameWithPrefix(Buffer, &GV, false);

  if (GV.isDeclaration())
    return;
  if (_mustPreserveSymbols.count(Buffer))
    mustPreserveList.push_back(GV.getName().data());
  if (_asmUndefinedRefs.count(Buffer))
    asmUsed.insert(&GV);
}

void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name,
                                      const GlobalValue *GV, Mangler &Mang,
                                      bool MayAlwaysUsePrivate) const {
  if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
    // Simple case: If GV is not private, it is not important to find out if
    // private labels are legal in this case or not.
    Mang.getNameWithPrefix(Name, GV, false);
    return;
  }
  SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, *this);
  const TargetLoweringObjectFile *TLOF = getObjFileLowering();
  const MCSection *TheSection = TLOF->SectionForGlobal(GV, GVKind, Mang, *this);
  bool CannotUsePrivateLabel = !canUsePrivateLabel(*AsmInfo, *TheSection);
  TLOF->getNameWithPrefix(Name, GV, CannotUsePrivateLabel, Mang, *this);
}

static MCSymbol *GetSymbolFromOperand(const MachineOperand &MO, AsmPrinter &AP){
  const TargetMachine &TM = AP.TM;
  Mangler *Mang = AP.Mang;
  const DataLayout *DL = TM.getSubtargetImpl()->getDataLayout();
  MCContext &Ctx = AP.OutContext;
  bool isDarwin = Triple(TM.getTargetTriple()).isOSDarwin();

  SmallString<128> Name;
  StringRef Suffix;
  if (MO.getTargetFlags() == PPCII::MO_PLT_OR_STUB) {
    if (isDarwin)
      Suffix = "$stub";
  } else if (MO.getTargetFlags() & PPCII::MO_NLP_FLAG)
    Suffix = "$non_lazy_ptr";

  if (!Suffix.empty())
    Name += DL->getPrivateGlobalPrefix();

  unsigned PrefixLen = Name.size();

  if (!MO.isGlobal()) {
    assert(MO.isSymbol() && "Isn't a symbol reference");
    Mang->getNameWithPrefix(Name, MO.getSymbolName());
  } else {
    const GlobalValue *GV = MO.getGlobal();
    TM.getNameWithPrefix(Name, GV, *Mang);
  }

  unsigned OrigLen = Name.size() - PrefixLen;

  Name += Suffix;
  MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
  StringRef OrigName = StringRef(Name).substr(PrefixLen, OrigLen);

  // If the target flags on the operand changes the name of the symbol, do that
  // before we return the symbol.
  if (MO.getTargetFlags() == PPCII::MO_PLT_OR_STUB && isDarwin) {
    MachineModuleInfoImpl::StubValueTy &StubSym =
      getMachOMMI(AP).getFnStubEntry(Sym);
    if (StubSym.getPointer())
      return Sym;
    
    if (MO.isGlobal()) {
      StubSym =
      MachineModuleInfoImpl::
      StubValueTy(AP.getSymbol(MO.getGlobal()),
                  !MO.getGlobal()->hasInternalLinkage());
    } else {
      StubSym =
      MachineModuleInfoImpl::
      StubValueTy(Ctx.GetOrCreateSymbol(OrigName), false);
    }
    return Sym;
  }

  // If the symbol reference is actually to a non_lazy_ptr, not to the symbol,
  // then add the suffix.
  if (MO.getTargetFlags() & PPCII::MO_NLP_FLAG) {
    MachineModuleInfoMachO &MachO = getMachOMMI(AP);
    
    MachineModuleInfoImpl::StubValueTy &StubSym =
      (MO.getTargetFlags() & PPCII::MO_NLP_HIDDEN_FLAG) ? 
         MachO.getHiddenGVStubEntry(Sym) : MachO.getGVStubEntry(Sym);
    
    if (!StubSym.getPointer()) {
      assert(MO.isGlobal() && "Extern symbol not handled yet");
      StubSym = MachineModuleInfoImpl::
                   StubValueTy(AP.getSymbol(MO.getGlobal()),
                               !MO.getGlobal()->hasInternalLinkage());
    }
    return Sym;
  }
  
  return Sym;
}

void TargetLoweringObjectFile::getNameWithPrefix(
    SmallVectorImpl<char> &OutName, const GlobalValue *GV, Mangler &Mang,
    const TargetMachine &TM) const {
  Mang.getNameWithPrefix(OutName, GV, /*CannotUsePrivateLabel=*/false);
}

void RecordStreamer::flushSymverDirectives() {
  // Mapping from mangled name to GV.
  StringMap<const GlobalValue *> MangledNameMap;
  // The name in the assembler will be mangled, but the name in the IR
  // might not, so we first compute a mapping from mangled name to GV.
  Mangler Mang;
  SmallString<64> MangledName;
  for (const GlobalValue &GV : M.global_values()) {
    if (!GV.hasName())
      continue;
    MangledName.clear();
    MangledName.reserve(GV.getName().size() + 1);
    Mang.getNameWithPrefix(MangledName, &GV, /*CannotUsePrivateLabel=*/false);
    MangledNameMap[MangledName] = &GV;
  }

  // Walk all the recorded .symver aliases, and set up the binding
  // for each alias.
  for (auto &Symver : SymverAliasMap) {
    const MCSymbol *Aliasee = Symver.first;
    MCSymbolAttr Attr = MCSA_Invalid;
    bool IsDefined = false;

    // First check if the aliasee binding was recorded in the asm.
    RecordStreamer::State state = getSymbolState(Aliasee);
    switch (state) {
    case RecordStreamer::Global:
    case RecordStreamer::DefinedGlobal:
      Attr = MCSA_Global;
      break;
    case RecordStreamer::UndefinedWeak:
    case RecordStreamer::DefinedWeak:
      Attr = MCSA_Weak;
      break;
    default:
      break;
    }

    switch (state) {
    case RecordStreamer::Defined:
    case RecordStreamer::DefinedGlobal:
    case RecordStreamer::DefinedWeak:
      IsDefined = true;
      break;
    case RecordStreamer::NeverSeen:
    case RecordStreamer::Global:
    case RecordStreamer::Used:
    case RecordStreamer::UndefinedWeak:
      break;
    }

    if (Attr == MCSA_Invalid || !IsDefined) {
      const GlobalValue *GV = M.getNamedValue(Aliasee->getName());
      if (!GV) {
        auto MI = MangledNameMap.find(Aliasee->getName());
        if (MI != MangledNameMap.end())
          GV = MI->second;
      }
      if (GV) {
        // If we don't have a symbol attribute from assembly, then check if
        // the aliasee was defined in the IR.
        if (Attr == MCSA_Invalid) {
          if (GV->hasExternalLinkage())
            Attr = MCSA_Global;
          else if (GV->hasLocalLinkage())
            Attr = MCSA_Local;
          else if (GV->isWeakForLinker())
            Attr = MCSA_Weak;
        }
        IsDefined = IsDefined || !GV->isDeclarationForLinker();
      }
    }

    // Set the detected binding on each alias with this aliasee.
    for (auto AliasName : Symver.second) {
      std::pair<StringRef, StringRef> Split = AliasName.split("@@@");
      SmallString<128> NewName;
      if (!Split.second.empty() && !Split.second.startswith("@")) {
        // Special processing for "@@@" according
        // https://sourceware.org/binutils/docs/as/Symver.html
        const char *Separator = IsDefined ? "@@" : "@";
        AliasName =
            (Split.first + Separator + Split.second).toStringRef(NewName);
      }
      MCSymbol *Alias = getContext().getOrCreateSymbol(AliasName);
      // TODO: Handle "@@@". Depending on SymbolAttribute value it needs to be
      // converted into @ or @@.
      const MCExpr *Value = MCSymbolRefExpr::create(Aliasee, getContext());
      if (IsDefined)
        markDefined(*Alias);
      // Don't use EmitAssignment override as it always marks alias as defined.
      MCStreamer::EmitAssignment(Alias, Value);
      if (Attr != MCSA_Invalid)
        EmitSymbolAttribute(Alias, Attr);
    }
  }
}

// Ensure ELF .symver aliases get the same binding as the defined symbol
// they alias with.
static void handleSymverAliases(const Module &M, RecordStreamer &Streamer) {
  if (Streamer.symverAliases().empty())
    return;

  // The name in the assembler will be mangled, but the name in the IR
  // might not, so we first compute a mapping from mangled name to GV.
  Mangler Mang;
  SmallString<64> MangledName;
  StringMap<const GlobalValue *> MangledNameMap;
  auto GetMangledName = [&](const GlobalValue &GV) {
    if (!GV.hasName())
      return;

    MangledName.clear();
    MangledName.reserve(GV.getName().size() + 1);
    Mang.getNameWithPrefix(MangledName, &GV, /*CannotUsePrivateLabel=*/false);
    MangledNameMap[MangledName] = &GV;
  };
  for (const Function &F : M)
    GetMangledName(F);
  for (const GlobalVariable &GV : M.globals())
    GetMangledName(GV);
  for (const GlobalAlias &GA : M.aliases())
    GetMangledName(GA);

  // Walk all the recorded .symver aliases, and set up the binding
  // for each alias.
  for (auto &Symver : Streamer.symverAliases()) {
    const MCSymbol *Aliasee = Symver.first;
    MCSymbolAttr Attr = MCSA_Invalid;

    // First check if the aliasee binding was recorded in the asm.
    RecordStreamer::State state = Streamer.getSymbolState(Aliasee);
    switch (state) {
    case RecordStreamer::Global:
    case RecordStreamer::DefinedGlobal:
      Attr = MCSA_Global;
      break;
    case RecordStreamer::UndefinedWeak:
    case RecordStreamer::DefinedWeak:
      Attr = MCSA_Weak;
      break;
    default:
      break;
    }

    // If we don't have a symbol attribute from assembly, then check if
    // the aliasee was defined in the IR.
    if (Attr == MCSA_Invalid) {
      const auto *GV = M.getNamedValue(Aliasee->getName());
      if (!GV) {
        auto MI = MangledNameMap.find(Aliasee->getName());
        if (MI != MangledNameMap.end())
          GV = MI->second;
        else
          continue;
      }
      if (GV->hasExternalLinkage())
        Attr = MCSA_Global;
      else if (GV->hasLocalLinkage())
        Attr = MCSA_Local;
      else if (GV->isWeakForLinker())
        Attr = MCSA_Weak;
    }
    if (Attr == MCSA_Invalid)
      continue;

    // Set the detected binding on each alias with this aliasee.
    for (auto &Alias : Symver.second)
      Streamer.EmitSymbolAttribute(Alias, Attr);
  }
}