C++ SmallString::clear方法代码示例

void EmitClangCommentHTMLNamedCharacterReferences(RecordKeeper &Records,
                                                  raw_ostream &OS) {
  std::vector<Record *> Tags = Records.getAllDerivedDefinitions("NCR");
  std::vector<StringMatcher::StringPair> NameToUTF8;
  SmallString<32> CLiteral;
  for (std::vector<Record *>::iterator I = Tags.begin(), E = Tags.end();
       I != E; ++I) {
    Record &Tag = **I;
    std::string Spelling = Tag.getValueAsString("Spelling");
    uint64_t CodePoint = Tag.getValueAsInt("CodePoint");
    CLiteral.clear();
    CLiteral.append("return ");
    if (!translateCodePointToUTF8(CodePoint, CLiteral)) {
      SrcMgr.PrintMessage(Tag.getLoc().front(),
                          SourceMgr::DK_Error,
                          Twine("invalid code point"));
      continue;
    }
    CLiteral.append(";");

    StringMatcher::StringPair Match(Spelling, CLiteral.str());
    NameToUTF8.push_back(Match);
  }

  emitSourceFileHeader("HTML named character reference to UTF-8 "
                       "translation", OS);

  OS << "StringRef translateHTMLNamedCharacterReferenceToUTF8(\n"
        "                                             StringRef Name) {\n";
  StringMatcher("Name", NameToUTF8, OS).Emit();
  OS << "  return StringRef();\n"
     << "}\n\n";
}

void SourceCoverageView::renderRegionMarkers(
    raw_ostream &OS, ArrayRef<const coverage::CoverageSegment *> Segments) {
  SmallString<32> Buffer;
  raw_svector_ostream BufferOS(Buffer);

  unsigned PrevColumn = 1;
  for (const auto *S : Segments) {
    if (!S->IsRegionEntry)
      continue;
    // Skip to the new region
    if (S->Col > PrevColumn)
      OS.indent(S->Col - PrevColumn);
    PrevColumn = S->Col + 1;
    BufferOS << S->Count;
    StringRef Str = BufferOS.str();
    // Trim the execution count
    Str = Str.substr(0, std::min(Str.size(), (size_t)7));
    PrevColumn += Str.size();
    OS << '^' << Str;
    Buffer.clear();
  }
  OS << "\n";

  if (Options.Debug)
    for (const auto *S : Segments)
      errs() << "Marker at " << S->Line << ":" << S->Col << " = " << S->Count
             << (S->IsRegionEntry ? "\n" : " (pop)\n");
}

void SourceCoverageView::renderRegionMarkers(raw_ostream &OS,
                                             ArrayRef<RegionMarker> Regions) {
  SmallString<32> Buffer;
  raw_svector_ostream BufferOS(Buffer);

  unsigned PrevColumn = 1;
  for (const auto &Region : Regions) {
    // Skip to the new region
    if (Region.Column > PrevColumn)
      OS.indent(Region.Column - PrevColumn);
    PrevColumn = Region.Column + 1;
    BufferOS << Region.ExecutionCount;
    StringRef Str = BufferOS.str();
    // Trim the execution count
    Str = Str.substr(0, std::min(Str.size(), (size_t)7));
    PrevColumn += Str.size();
    OS << '^' << Str;
    Buffer.clear();
  }
  OS << "\n";

  if (Options.Debug) {
    for (const auto &Region : Regions) {
      errs() << "Marker at " << Region.Line << ":" << Region.Column << " = "
             << Region.ExecutionCount << "\n";
    }
  }
}

void CodeViewDebug::emitLocalVariable(const LocalVariable &Var) {
  // LocalSym record, see SymbolRecord.h for more info.
  MCSymbol *LocalBegin = MMI->getContext().createTempSymbol(),
           *LocalEnd = MMI->getContext().createTempSymbol();
  OS.AddComment("Record length");
  OS.emitAbsoluteSymbolDiff(LocalEnd, LocalBegin, 2);
  OS.EmitLabel(LocalBegin);

  OS.AddComment("Record kind: S_LOCAL");
  OS.EmitIntValue(unsigned(SymbolRecordKind::S_LOCAL), 2);

  uint16_t Flags = 0;
  if (Var.DIVar->isParameter())
    Flags |= LocalSym::IsParameter;
  if (Var.DefRanges.empty())
    Flags |= LocalSym::IsOptimizedOut;

  OS.AddComment("TypeIndex");
  OS.EmitIntValue(TypeIndex::Int32().getIndex(), 4);
  OS.AddComment("Flags");
  OS.EmitIntValue(Flags, 2);
  // Truncate the name so we won't overflow the record length field.
  emitNullTerminatedSymbolName(OS, Var.DIVar->getName());
  OS.EmitLabel(LocalEnd);

  // Calculate the on disk prefix of the appropriate def range record. The
  // records and on disk formats are described in SymbolRecords.h. BytePrefix
  // should be big enough to hold all forms without memory allocation.
  SmallString<20> BytePrefix;
  for (const LocalVarDefRange &DefRange : Var.DefRanges) {
    BytePrefix.clear();
    // FIXME: Handle bitpieces.
    if (DefRange.StructOffset != 0)
      continue;

    if (DefRange.InMemory) {
      DefRangeRegisterRelSym Sym{};
      ulittle16_t SymKind = ulittle16_t(S_DEFRANGE_REGISTER_REL);
      Sym.BaseRegister = DefRange.CVRegister;
      Sym.Flags = 0; // Unclear what matters here.
      Sym.BasePointerOffset = DefRange.DataOffset;
      BytePrefix +=
          StringRef(reinterpret_cast<const char *>(&SymKind), sizeof(SymKind));
      BytePrefix += StringRef(reinterpret_cast<const char *>(&Sym),
                              sizeof(Sym) - sizeof(LocalVariableAddrRange));
    } else {
      assert(DefRange.DataOffset == 0 && "unexpected offset into register");
      DefRangeRegisterSym Sym{};
      ulittle16_t SymKind = ulittle16_t(S_DEFRANGE_REGISTER);
      Sym.Register = DefRange.CVRegister;
      Sym.MayHaveNoName = 0; // Unclear what matters here.
      BytePrefix +=
          StringRef(reinterpret_cast<const char *>(&SymKind), sizeof(SymKind));
      BytePrefix += StringRef(reinterpret_cast<const char *>(&Sym),
                              sizeof(Sym) - sizeof(LocalVariableAddrRange));
    }
    OS.EmitCVDefRangeDirective(DefRange.Ranges, BytePrefix);
  }
}

void InitHeaderSearch::AddPath(const Twine &Path,
                               IncludeDirGroup Group, bool isCXXAware,
                               bool isUserSupplied, bool isFramework,
                               bool IgnoreSysRoot) {
  assert(!Path.isTriviallyEmpty() && "can't handle empty path here");
  FileManager &FM = Headers.getFileMgr();

  // Compute the actual path, taking into consideration -isysroot.
  SmallString<256> MappedPathStorage;
  StringRef MappedPathStr = Path.toStringRef(MappedPathStorage);

  // Handle isysroot.
  if ((Group == System || Group == CXXSystem) && !IgnoreSysRoot &&
#if defined(_WIN32)
      !MappedPathStr.empty() &&
      llvm::sys::path::is_separator(MappedPathStr[0]) &&
#else
      llvm::sys::path::is_absolute(MappedPathStr) &&
#endif
      IsNotEmptyOrRoot) {
    MappedPathStorage.clear();
    MappedPathStr =
      (IncludeSysroot + Path).toStringRef(MappedPathStorage);
  }

  // Compute the DirectoryLookup type.
  SrcMgr::CharacteristicKind Type;
  if (Group == Quoted || Group == Angled || Group == IndexHeaderMap)
    Type = SrcMgr::C_User;
  else if (isCXXAware)
    Type = SrcMgr::C_System;
  else
    Type = SrcMgr::C_ExternCSystem;


  // If the directory exists, add it.
  if (const DirectoryEntry *DE = FM.getDirectory(MappedPathStr)) {
    IncludePath.push_back(std::make_pair(Group, DirectoryLookup(DE, Type,
                          isUserSupplied, isFramework)));
    return;
  }

  // Check to see if this is an apple-style headermap (which are not allowed to
  // be frameworks).
  if (!isFramework) {
    if (const FileEntry *FE = FM.getFile(MappedPathStr)) {
      if (const HeaderMap *HM = Headers.CreateHeaderMap(FE)) {
        // It is a headermap, add it to the search path.
        IncludePath.push_back(std::make_pair(Group, DirectoryLookup(HM, Type,
                              isUserSupplied, Group == IndexHeaderMap)));
        return;
      }
    }
  }

  if (Verbose)
    llvm::errs() << "ignoring nonexistent directory \""
                 << MappedPathStr << "\"\n";
}

ErrorOr<StringRef> ELFLinkingContext::searchLibrary(StringRef libName) const {
  bool foundFile = false;
  StringRef pathref;
  SmallString<128> path;
  for (StringRef dir : _inputSearchPaths) {
    // Search for dynamic library
    if (!_isStaticExecutable) {
      path.clear();
      if (dir.startswith("=/")) {
        path.assign(_sysrootPath);
        path.append(dir.substr(1));
      } else {
        path.assign(dir);
      }
      llvm::sys::path::append(path, Twine("lib") + libName + ".so");
      pathref = path.str();
      if (llvm::sys::fs::exists(pathref)) {
        foundFile = true;
      }
    }
    // Search for static libraries too
    if (!foundFile) {
      path.clear();
      if (dir.startswith("=/")) {
        path.assign(_sysrootPath);
        path.append(dir.substr(1));
      } else {
        path.assign(dir);
      }
      llvm::sys::path::append(path, Twine("lib") + libName + ".a");
      pathref = path.str();
      if (llvm::sys::fs::exists(pathref)) {
        foundFile = true;
      }
    }
    if (foundFile)
      return StringRef(*new (_allocator) std::string(pathref));
  }
  if (!llvm::sys::fs::exists(libName))
    return llvm::make_error_code(llvm::errc::no_such_file_or_directory);

  return libName;
}

std::unique_ptr<Input::HNode> Input::createHNodes(Node *N) {
  SmallString<128> StringStorage;
  if (ScalarNode *SN = dyn_cast<ScalarNode>(N)) {
    StringRef KeyStr = SN->getValue(StringStorage);
    if (!StringStorage.empty()) {
      // Copy string to permanent storage
      KeyStr = StringStorage.str().copy(StringAllocator);
    }
    return llvm::make_unique<ScalarHNode>(N, KeyStr);
  } else if (BlockScalarNode *BSN = dyn_cast<BlockScalarNode>(N)) {
    StringRef ValueCopy = BSN->getValue().copy(StringAllocator);
    return llvm::make_unique<ScalarHNode>(N, ValueCopy);
  } else if (SequenceNode *SQ = dyn_cast<SequenceNode>(N)) {
    auto SQHNode = llvm::make_unique<SequenceHNode>(N);
    for (Node &SN : *SQ) {
      auto Entry = createHNodes(&SN);
      if (EC)
        break;
      SQHNode->Entries.push_back(std::move(Entry));
    }
    return std::move(SQHNode);
  } else if (MappingNode *Map = dyn_cast<MappingNode>(N)) {
    auto mapHNode = llvm::make_unique<MapHNode>(N);
    for (KeyValueNode &KVN : *Map) {
      Node *KeyNode = KVN.getKey();
      ScalarNode *Key = dyn_cast<ScalarNode>(KeyNode);
      Node *Value = KVN.getValue();
      if (!Key || !Value) {
        if (!Key)
          setError(KeyNode, "Map key must be a scalar");
        if (!Value)
          setError(KeyNode, "Map value must not be empty");
        break;
      }
      StringStorage.clear();
      StringRef KeyStr = Key->getValue(StringStorage);
      if (!StringStorage.empty()) {
        // Copy string to permanent storage
        KeyStr = StringStorage.str().copy(StringAllocator);
      }
      auto ValueHNode = createHNodes(Value);
      if (EC)
        break;
      mapHNode->Mapping[KeyStr] = std::move(ValueHNode);
    }
    return std::move(mapHNode);
  } else if (isa<NullNode>(N)) {
    return llvm::make_unique<EmptyHNode>(N);
  } else {
    setError(N, "unknown node kind");
    return nullptr;
  }
}

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.
  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);
    Mangler::getNameWithPrefix(MangledName, GV.getName(),
                               MergedModule->getDataLayout());
    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;
}

Input::HNode *Input::createHNodes(Node *N) {
  SmallString<128> StringStorage;
  if (ScalarNode *SN = dyn_cast<ScalarNode>(N)) {
    StringRef KeyStr = SN->getValue(StringStorage);
    if (!StringStorage.empty()) {
      // Copy string to permanent storage
      unsigned Len = StringStorage.size();
      char *Buf = StringAllocator.Allocate<char>(Len);
      memcpy(Buf, &StringStorage[0], Len);
      KeyStr = StringRef(Buf, Len);
    }
    return new ScalarHNode(N, KeyStr);
  } else if (SequenceNode *SQ = dyn_cast<SequenceNode>(N)) {
    SequenceHNode *SQHNode = new SequenceHNode(N);
    for (Node &SN : *SQ) {
      HNode *Entry = this->createHNodes(&SN);
      if (EC)
        break;
      SQHNode->Entries.push_back(Entry);
    }
    return SQHNode;
  } else if (MappingNode *Map = dyn_cast<MappingNode>(N)) {
    MapHNode *mapHNode = new MapHNode(N);
    for (KeyValueNode &KVN : *Map) {
      Node *KeyNode = KVN.getKey();
      ScalarNode *KeyScalar = dyn_cast<ScalarNode>(KeyNode);
      if (!KeyScalar) {
        setError(KeyNode, "Map key must be a scalar");
        break;
      }
      StringStorage.clear();
      StringRef KeyStr = KeyScalar->getValue(StringStorage);
      if (!StringStorage.empty()) {
        // Copy string to permanent storage
        unsigned Len = StringStorage.size();
        char *Buf = StringAllocator.Allocate<char>(Len);
        memcpy(Buf, &StringStorage[0], Len);
        KeyStr = StringRef(Buf, Len);
      }
      HNode *ValueHNode = this->createHNodes(KVN.getValue());
      if (EC)
        break;
      mapHNode->Mapping[KeyStr] = ValueHNode;
    }
    return mapHNode;
  } else if (isa<NullNode>(N)) {
    return new EmptyHNode(N);
  } else {
    setError(N, "unknown node kind");
    return nullptr;
  }
}

Input::HNode *Input::createHNodes(Node *N) {
  SmallString<128> StringStorage;
  if (ScalarNode *SN = dyn_cast<ScalarNode>(N)) {
    StringRef KeyStr = SN->getValue(StringStorage);
    if (!StringStorage.empty()) {
      // Copy string to permanent storage
      unsigned Len = StringStorage.size();
      char *Buf = StringAllocator.Allocate<char>(Len);
      memcpy(Buf, &StringStorage[0], Len);
      KeyStr = StringRef(Buf, Len);
    }
    return new ScalarHNode(N, KeyStr);
  } else if (SequenceNode *SQ = dyn_cast<SequenceNode>(N)) {
    SequenceHNode *SQHNode = new SequenceHNode(N);
    for (SequenceNode::iterator i = SQ->begin(), End = SQ->end(); i != End;
         ++i) {
      HNode *Entry = this->createHNodes(i);
      if (EC)
        break;
      SQHNode->Entries.push_back(Entry);
    }
    return SQHNode;
  } else if (MappingNode *Map = dyn_cast<MappingNode>(N)) {
    MapHNode *mapHNode = new MapHNode(N);
    for (MappingNode::iterator i = Map->begin(), End = Map->end(); i != End;
         ++i) {
      ScalarNode *KeyScalar = dyn_cast<ScalarNode>(i->getKey());
      StringStorage.clear();
      StringRef KeyStr = KeyScalar->getValue(StringStorage);
      if (!StringStorage.empty()) {
        // Copy string to permanent storage
        unsigned Len = StringStorage.size();
        char *Buf = StringAllocator.Allocate<char>(Len);
        memcpy(Buf, &StringStorage[0], Len);
        KeyStr = StringRef(Buf, Len);
      }
      HNode *ValueHNode = this->createHNodes(i->getValue());
      if (EC)
        break;
      mapHNode->Mapping[KeyStr] = ValueHNode;
    }
    return mapHNode;
  } else if (isa<NullNode>(N)) {
    return new EmptyHNode(N);
  } else {
    setError(N, "unknown node kind");
    return NULL;
  }
}

/// \brief Compute the relative path that names the given file relative to
/// the given directory.
static void computeRelativePath(FileManager &FM, const DirectoryEntry *Dir,
                                const FileEntry *File,
                                SmallString<128> &Result) {
  Result.clear();

  StringRef FilePath = File->getDir()->getName();
  StringRef Path = FilePath;
  while (!Path.empty()) {
    if (const DirectoryEntry *CurDir = FM.getDirectory(Path)) {
      if (CurDir == Dir) {
        Result = FilePath.substr(Path.size());
        llvm::sys::path::append(Result, 
                                llvm::sys::path::filename(File->getName()));
        return;
      }
    }
    
    Path = llvm::sys::path::parent_path(Path);
  }
  
  Result = File->getName();
}

/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
/// module from a type definition in the source module.
void TypeMapTy::linkDefinedTypeBodies() {
  SmallVector<Type*, 16> Elements;
  SmallString<16> TmpName;
  
  // Note that processing entries in this loop (calling 'get') can add new
  // entries to the SrcDefinitionsToResolve vector.
  while (!SrcDefinitionsToResolve.empty()) {
    StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val();
    StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
    
    // TypeMap is a many-to-one mapping, if there were multiple types that
    // provide a body for DstSTy then previous iterations of this loop may have
    // already handled it.  Just ignore this case.
    if (!DstSTy->isOpaque()) continue;
    assert(!SrcSTy->isOpaque() && "Not resolving a definition?");
    
    // Map the body of the source type over to a new body for the dest type.
    Elements.resize(SrcSTy->getNumElements());
    for (unsigned i = 0, e = Elements.size(); i != e; ++i)
      Elements[i] = getImpl(SrcSTy->getElementType(i));
    
    DstSTy->setBody(Elements, SrcSTy->isPacked());
    
    // If DstSTy has no name or has a longer name than STy, then viciously steal
    // STy's name.
    if (!SrcSTy->hasName()) continue;
    StringRef SrcName = SrcSTy->getName();
    
    if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) {
      TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end());
      SrcSTy->setName("");
      DstSTy->setName(TmpName.str());
      TmpName.clear();
    }
  }
  
  DstResolvedOpaqueTypes.clear();
}

// Build the unmodified AsmString used by the IR.  Also build the individual
// asm instruction(s) and place them in the AsmStrings vector; these are fed
// to the AsmParser.
static std::string buildMSAsmString(Sema &SemaRef, ArrayRef<Token> AsmToks,
                                    std::vector<std::string> &AsmStrings,
                     std::vector<std::pair<unsigned,unsigned> > &AsmTokRanges) {
  assert (!AsmToks.empty() && "Didn't expect an empty AsmToks!");

  SmallString<512> Res;
  SmallString<512> Asm;
  unsigned startTok = 0;
  for (unsigned i = 0, e = AsmToks.size(); i < e; ++i) {
    bool isNewAsm = i == 0 || AsmToks[i].isAtStartOfLine() ||
      AsmToks[i].is(tok::kw_asm);

    if (isNewAsm) {
      if (i) {
        AsmStrings.push_back(Asm.str());
        AsmTokRanges.push_back(std::make_pair(startTok, i-1));
        startTok = i;
        Res += Asm;
        Asm.clear();
        Res += '\n';
      }
      if (AsmToks[i].is(tok::kw_asm)) {
        i++; // Skip __asm
        assert (i != e && "Expected another token");
      }
    }

    if (i && AsmToks[i].hasLeadingSpace() && !isNewAsm)
      Asm += ' ';

    Asm += getSpelling(SemaRef, AsmToks[i]);
  }
  AsmStrings.push_back(Asm.str());
  AsmTokRanges.push_back(std::make_pair(startTok, AsmToks.size()-1));
  Res += Asm;
  return Res.str();
}

//.........这里部分代码省略.........
    verify(emitLoadOfAlignmentMask(IGF, layoutType),
           getAlignmentMaskConstant(fixedTI->getFixedAlignment()),
           "alignment mask");
    verify(emitLoadOfStride(IGF, layoutType),
           getSizeConstant(fixedTI->getFixedStride()),
           "stride");
    verify(emitLoadOfIsInline(IGF, layoutType),
           getBoolConstant(fixedTI->getFixedPacking(IGF.IGM)
                             == FixedPacking::OffsetZero),
           "is-inline bit");
    verify(emitLoadOfIsPOD(IGF, layoutType),
           getBoolConstant(fixedTI->isPOD(ResilienceExpansion::Maximal)),
           "is-POD bit");
    verify(emitLoadOfIsBitwiseTakable(IGF, layoutType),
           getBoolConstant(fixedTI->isBitwiseTakable(ResilienceExpansion::Maximal)),
           "is-bitwise-takable bit");
    unsigned xiCount = fixedTI->getFixedExtraInhabitantCount(IGF.IGM);
    verify(emitLoadOfHasExtraInhabitants(IGF, layoutType),
           getBoolConstant(xiCount != 0),
           "has-extra-inhabitants bit");

    // Check extra inhabitants.
    if (xiCount > 0) {
      verify(emitLoadOfExtraInhabitantCount(IGF, layoutType),
             getSizeConstant(Size(xiCount)),
             "extra inhabitant count");
      
      // Verify that the extra inhabitant representations are consistent.
      
      // TODO: Update for EnumPayload implementation changes.
#if 0
      auto xiBuf = IGF.createAlloca(fixedTI->getStorageType(),
                                    fixedTI->getFixedAlignment(),
                                    "extra-inhabitant");
      auto xiOpaque = IGF.Builder.CreateBitCast(xiBuf, IGF.IGM.OpaquePtrTy);
      
      // TODO: Randomize the set of extra inhabitants we check.
      unsigned bits = fixedTI->getFixedSize().getValueInBits();
      for (unsigned i = 0, e = std::min(xiCount, 1024u);
           i < e; ++i) {
        // Initialize the buffer with junk, to help ensure we're insensitive to
        // insignificant bits.
        // TODO: Randomize the filler.
        IGF.Builder.CreateMemSet(xiBuf.getAddress(),
                                 llvm::ConstantInt::get(IGF.IGM.Int8Ty, 0x5A),
                                 fixedTI->getFixedSize().getValue(),
                                 fixedTI->getFixedAlignment().getValue());
        
        // Ask the runtime to store an extra inhabitant.
        auto index = llvm::ConstantInt::get(IGF.IGM.Int32Ty, i);
        emitStoreExtraInhabitantCall(IGF, layoutType, index,
                                     xiOpaque.getAddress());
        
        // Compare the stored extra inhabitant against the fixed extra
        // inhabitant pattern.
        auto fixedXI = fixedTI->getFixedExtraInhabitantValue(IGF.IGM, bits, i);
        auto xiBuf2 = IGF.Builder.CreateBitCast(xiBuf,
                                            fixedXI->getType()->getPointerTo());
        llvm::Value *runtimeXI = IGF.Builder.CreateLoad(xiBuf2);
        runtimeXI = fixedTI->maskFixedExtraInhabitant(IGF, runtimeXI);
        
        numberBuf.clear();
        {
          llvm::raw_svector_ostream os(numberBuf);
          os << i;
          os.flush();
        }
        
        verify(runtimeXI, fixedXI,
               llvm::Twine("stored extra inhabitant ") + numberBuf.str());
        
        // Now store the fixed extra inhabitant and ask the runtime to identify
        // it.
        // Mask in junk to make sure the runtime correctly ignores it.
        auto xiMask = fixedTI->getFixedExtraInhabitantMask(IGF.IGM).asAPInt();
        auto maskVal = llvm::ConstantInt::get(IGF.IGM.getLLVMContext(), xiMask);
        auto notMaskVal
          = llvm::ConstantInt::get(IGF.IGM.getLLVMContext(), ~xiMask);
        // TODO: Randomize the filler.
        auto xiFill = llvm::ConstantInt::getAllOnesValue(fixedXI->getType());
        llvm::Value *xiFillMask = IGF.Builder.CreateAnd(notMaskVal, xiFill);
        llvm::Value *xiValMask = IGF.Builder.CreateAnd(maskVal, fixedXI);
        llvm::Value *filledXI = IGF.Builder.CreateOr(xiFillMask, xiValMask);
        
        IGF.Builder.CreateStore(filledXI, xiBuf2);
        
        auto runtimeIndex = emitGetExtraInhabitantIndexCall(IGF, layoutType,
                                                        xiOpaque.getAddress());
        verify(runtimeIndex, index,
               llvm::Twine("extra inhabitant index calculation ")
                 + numberBuf.str());
      }
#endif
    }

    // TODO: Verify interesting layout properties specific to the kind of type,
    // such as struct or class field offsets, enum case tags, vtable entries,
    // etc.
  }
}

// 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);
  }
}