C++ SmallString类代码示例

void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
                                            const HeaderSearchOptions &HSOpts) {
  llvm::Triple::OSType os = triple.getOS();

  if (HSOpts.UseStandardSystemIncludes) {
    switch (os) {
    case llvm::Triple::FreeBSD:
    case llvm::Triple::NetBSD:
    case llvm::Triple::OpenBSD:
    case llvm::Triple::Bitrig:
      break;
    default:
      // FIXME: temporary hack: hard-coded paths.
      AddPath("/usr/local/include", System, false);
      break;
    }
  }

  // Builtin includes use #include_next directives and should be positioned
  // just prior C include dirs.
  if (HSOpts.UseBuiltinIncludes) {
    // Ignore the sys root, we *always* look for clang headers relative to
    // supplied path.
    SmallString<128> P = StringRef(HSOpts.ResourceDir);
    llvm::sys::path::append(P, "include");
    AddUnmappedPath(P.str(), ExternCSystem, false);
  }

  // All remaining additions are for system include directories, early exit if
  // we aren't using them.
  if (!HSOpts.UseStandardSystemIncludes)
    return;

  // Add dirs specified via 'configure --with-c-include-dirs'.
  StringRef CIncludeDirs(C_INCLUDE_DIRS);
  if (CIncludeDirs != "") {
    SmallVector<StringRef, 5> dirs;
    CIncludeDirs.split(dirs, ":");
    for (SmallVectorImpl<StringRef>::iterator i = dirs.begin();
         i != dirs.end();
         ++i)
      AddPath(*i, ExternCSystem, false);
    return;
  }

  switch (os) {
  case llvm::Triple::Linux:
  case llvm::Triple::Win32:
    llvm_unreachable("Include management is handled in the driver.");

  case llvm::Triple::Haiku:
    AddPath("/boot/common/include", System, false);
    AddPath("/boot/develop/headers/os", System, false);
    AddPath("/boot/develop/headers/os/app", System, false);
    AddPath("/boot/develop/headers/os/arch", System, false);
    AddPath("/boot/develop/headers/os/device", System, false);
    AddPath("/boot/develop/headers/os/drivers", System, false);
    AddPath("/boot/develop/headers/os/game", System, false);
    AddPath("/boot/develop/headers/os/interface", System, false);
    AddPath("/boot/develop/headers/os/kernel", System, false);
    AddPath("/boot/develop/headers/os/locale", System, false);
    AddPath("/boot/develop/headers/os/mail", System, false);
    AddPath("/boot/develop/headers/os/media", System, false);
    AddPath("/boot/develop/headers/os/midi", System, false);
    AddPath("/boot/develop/headers/os/midi2", System, false);
    AddPath("/boot/develop/headers/os/net", System, false);
    AddPath("/boot/develop/headers/os/storage", System, false);
    AddPath("/boot/develop/headers/os/support", System, false);
    AddPath("/boot/develop/headers/os/translation", System, false);
    AddPath("/boot/develop/headers/os/add-ons/graphics", System, false);
    AddPath("/boot/develop/headers/os/add-ons/input_server", System, false);
    AddPath("/boot/develop/headers/os/add-ons/screen_saver", System, false);
    AddPath("/boot/develop/headers/os/add-ons/tracker", System, false);
    AddPath("/boot/develop/headers/os/be_apps/Deskbar", System, false);
    AddPath("/boot/develop/headers/os/be_apps/NetPositive", System, false);
    AddPath("/boot/develop/headers/os/be_apps/Tracker", System, false);
    AddPath("/boot/develop/headers/cpp", System, false);
    AddPath("/boot/develop/headers/cpp/i586-pc-haiku", System, false);
    AddPath("/boot/develop/headers/3rdparty", System, false);
    AddPath("/boot/develop/headers/bsd", System, false);
    AddPath("/boot/develop/headers/glibc", System, false);
    AddPath("/boot/develop/headers/posix", System, false);
    AddPath("/boot/develop/headers",  System, false);
    break;
  case llvm::Triple::RTEMS:
    break;
  case llvm::Triple::Cygwin:
    // The headers in w32api/ are not cygwin-compatible (but native)
    //AddPath("/usr/include/w32api", System, false);
    break;
  case llvm::Triple::MinGW32: { 
      // mingw-w64 crt include paths
      // <sysroot>/i686-w64-mingw32/include
      SmallString<128> P = StringRef(HSOpts.ResourceDir);
      llvm::sys::path::append(P, "../../../i686-w64-mingw32/include");
      AddPath(P.str(), System, false);

      // <sysroot>/x86_64-w64-mingw32/include
      P.resize(HSOpts.ResourceDir.size());
      llvm::sys::path::append(P, "../../../x86_64-w64-mingw32/include");
//.........这里部分代码省略.........

/// runPasses - Run the specified passes on Program, outputting a bitcode file
/// and writing the filename into OutputFile if successful.  If the
/// optimizations fail for some reason (optimizer crashes), return true,
/// otherwise return false.  If DeleteOutput is set to true, the bitcode is
/// deleted on success, and the filename string is undefined.  This prints to
/// outs() a single line message indicating whether compilation was successful
/// or failed.
///
bool BugDriver::runPasses(Module &Program,
                          const std::vector<std::string> &Passes,
                          std::string &OutputFilename, bool DeleteOutput,
                          bool Quiet, unsigned NumExtraArgs,
                          const char *const *ExtraArgs) const {
  // setup the output file name
  outs().flush();
  SmallString<128> UniqueFilename;
  std::error_code EC = sys::fs::createUniqueFile(
      OutputPrefix + "-output-%%%%%%%.bc", UniqueFilename);
  if (EC) {
    errs() << getToolName()
           << ": Error making unique filename: " << EC.message() << "\n";
    return 1;
  }
  OutputFilename = UniqueFilename.str();

  // set up the input file name
  Expected<sys::fs::TempFile> Temp =
      sys::fs::TempFile::create(OutputPrefix + "-input-%%%%%%%.bc");
  if (!Temp) {
    errs() << getToolName()
           << ": Error making unique filename: " << toString(Temp.takeError())
           << "\n";
    return 1;
  }
  DiscardTemp Discard{*Temp};
  raw_fd_ostream OS(Temp->FD, /*shouldClose*/ false);

  WriteBitcodeToFile(Program, OS, PreserveBitcodeUseListOrder);
  OS.flush();
  if (OS.has_error()) {
    errs() << "Error writing bitcode file: " << Temp->TmpName << "\n";
    OS.clear_error();
    return 1;
  }

  std::string tool = OptCmd;
  if (OptCmd.empty()) {
    if (ErrorOr<std::string> Path = sys::findProgramByName("opt"))
      tool = *Path;
    else
      errs() << Path.getError().message() << "\n";
  }
  if (tool.empty()) {
    errs() << "Cannot find `opt' in PATH!\n";
    return 1;
  }
  if (!sys::fs::exists(tool)) {
    errs() << "Specified `opt' binary does not exist: " << tool << "\n";
    return 1;
  }

  std::string Prog;
  if (UseValgrind) {
    if (ErrorOr<std::string> Path = sys::findProgramByName("valgrind"))
      Prog = *Path;
    else
      errs() << Path.getError().message() << "\n";
  } else
    Prog = tool;
  if (Prog.empty()) {
    errs() << "Cannot find `valgrind' in PATH!\n";
    return 1;
  }

  // setup the child process' arguments
  SmallVector<StringRef, 8> Args;
  if (UseValgrind) {
    Args.push_back("valgrind");
    Args.push_back("--error-exitcode=1");
    Args.push_back("-q");
    Args.push_back(tool);
  } else
    Args.push_back(tool);

  for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
    Args.push_back(OptArgs[i]);
  Args.push_back("-disable-symbolication");
  Args.push_back("-o");
  Args.push_back(OutputFilename);
  std::vector<std::string> pass_args;
  for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
    pass_args.push_back(std::string("-load"));
    pass_args.push_back(PluginLoader::getPlugin(i));
  }
  for (std::vector<std::string>::const_iterator I = Passes.begin(),
                                                E = Passes.end();
       I != E; ++I)
    pass_args.push_back(std::string("-") + (*I));
  for (std::vector<std::string>::const_iterator I = pass_args.begin(),
                                                E = pass_args.end();
//.........这里部分代码省略.........

void MCStreamer::EmitRawTextAsm(const Twine &T) {
  SmallString<128> Str;
  T.toVector(Str);
  EmitRawTextAsm(Str.str());
}

const char *ArgList::MakeArgString(const Twine &T) const {
  SmallString<256> Str;
  T.toVector(Str);
  return MakeArgString(Str.str());
}

void Preprocessor::HandlePragmaIncludeAlias(Token &Tok) {
  // We will either get a quoted filename or a bracketed filename, and we 
  // have to track which we got.  The first filename is the source name,
  // and the second name is the mapped filename.  If the first is quoted,
  // the second must be as well (cannot mix and match quotes and brackets).

  // Get the open paren
  Lex(Tok);
  if (Tok.isNot(tok::l_paren)) {
    Diag(Tok, diag::warn_pragma_include_alias_expected) << "(";
    return;
  }

  // We expect either a quoted string literal, or a bracketed name
  Token SourceFilenameTok;
  CurPPLexer->LexIncludeFilename(SourceFilenameTok);
  if (SourceFilenameTok.is(tok::eod)) {
    // The diagnostic has already been handled
    return;
  }

  StringRef SourceFileName;
  SmallString<128> FileNameBuffer;
  if (SourceFilenameTok.is(tok::string_literal) || 
      SourceFilenameTok.is(tok::angle_string_literal)) {
    SourceFileName = getSpelling(SourceFilenameTok, FileNameBuffer);
  } else if (SourceFilenameTok.is(tok::less)) {
    // This could be a path instead of just a name
    FileNameBuffer.push_back('<');
    SourceLocation End;
    if (ConcatenateIncludeName(FileNameBuffer, End))
      return; // Diagnostic already emitted
    SourceFileName = FileNameBuffer.str();
  } else {
    Diag(Tok, diag::warn_pragma_include_alias_expected_filename);
    return;
  }
  FileNameBuffer.clear();

  // Now we expect a comma, followed by another include name
  Lex(Tok);
  if (Tok.isNot(tok::comma)) {
    Diag(Tok, diag::warn_pragma_include_alias_expected) << ",";
    return;
  }

  Token ReplaceFilenameTok;
  CurPPLexer->LexIncludeFilename(ReplaceFilenameTok);
  if (ReplaceFilenameTok.is(tok::eod)) {
    // The diagnostic has already been handled
    return;
  }

  StringRef ReplaceFileName;
  if (ReplaceFilenameTok.is(tok::string_literal) || 
      ReplaceFilenameTok.is(tok::angle_string_literal)) {
    ReplaceFileName = getSpelling(ReplaceFilenameTok, FileNameBuffer);
  } else if (ReplaceFilenameTok.is(tok::less)) {
    // This could be a path instead of just a name
    FileNameBuffer.push_back('<');
    SourceLocation End;
    if (ConcatenateIncludeName(FileNameBuffer, End))
      return; // Diagnostic already emitted
    ReplaceFileName = FileNameBuffer.str();
  } else {
    Diag(Tok, diag::warn_pragma_include_alias_expected_filename);
    return;
  }

  // Finally, we expect the closing paren
  Lex(Tok);
  if (Tok.isNot(tok::r_paren)) {
    Diag(Tok, diag::warn_pragma_include_alias_expected) << ")";
    return;
  }

  // Now that we have the source and target filenames, we need to make sure
  // they're both of the same type (angled vs non-angled)
  StringRef OriginalSource = SourceFileName;

  bool SourceIsAngled = 
    GetIncludeFilenameSpelling(SourceFilenameTok.getLocation(), 
                                SourceFileName);
  bool ReplaceIsAngled =
    GetIncludeFilenameSpelling(ReplaceFilenameTok.getLocation(),
                                ReplaceFileName);
  if (!SourceFileName.empty() && !ReplaceFileName.empty() &&
      (SourceIsAngled != ReplaceIsAngled)) {
    unsigned int DiagID;
    if (SourceIsAngled)
      DiagID = diag::warn_pragma_include_alias_mismatch_angle;
    else
      DiagID = diag::warn_pragma_include_alias_mismatch_quote;

    Diag(SourceFilenameTok.getLocation(), DiagID)
      << SourceFileName 
      << ReplaceFileName;

    return;
  }
//.........这里部分代码省略.........

  bool WriteBundleEnd(raw_fd_ostream &OS, StringRef TargetTriple) final {
    assert(NumberOfProcessedInputs <= NumberOfInputs &&
           "Processing more inputs that actually exist!");
    assert(HostInputIndex != ~0u && "Host input index not defined.");

    // If this is not the last output, we don't have to do anything.
    if (NumberOfProcessedInputs != NumberOfInputs)
      return false;

    // Create the bitcode file name to write the resulting code to. Keep it if
    // save-temps is active.
    SmallString<128> BitcodeFileName;
    if (sys::fs::createTemporaryFile("clang-offload-bundler", "bc",
                                     BitcodeFileName)) {
      errs() << "error: unable to create temporary file.\n";
      return true;
    }

    // Dump the contents of the temporary file if that was requested.
    if (DumpTemporaryFiles) {
      errs() << ";\n; Object file bundler IR file.\n;\n";
      AuxModule.get()->print(errs(), nullptr,
                             /*ShouldPreserveUseListOrder=*/false,
                             /*IsForDebug=*/true);
      errs() << '\n';
    }

    // Find clang in order to create the bundle binary.
    StringRef Dir = sys::path::parent_path(BundlerExecutable);

    auto ClangBinary = sys::findProgramByName("clang", Dir);
    if (ClangBinary.getError()) {
      // Remove bitcode file.
      sys::fs::remove(BitcodeFileName);

      errs() << "error: unable to find 'clang' in path.\n";
      return true;
    }

    // Do the incremental linking. We write to the output file directly. So, we
    // close it and use the name to pass down to clang.
    OS.close();
    SmallString<128> TargetName = getTriple(TargetNames[HostInputIndex]);
    std::vector<StringRef> ClangArgs = {"clang",
                                        "-r",
                                        "-target",
                                        TargetName.c_str(),
                                        "-o",
                                        OutputFileNames.front().c_str(),
                                        InputFileNames[HostInputIndex].c_str(),
                                        BitcodeFileName.c_str(),
                                        "-nostdlib"};

    // If the user asked for the commands to be printed out, we do that instead
    // of executing it.
    if (PrintExternalCommands) {
      errs() << "\"" << ClangBinary.get() << "\"";
      for (StringRef Arg : ClangArgs)
        errs() << " \"" << Arg << "\"";
      errs() << "\n";
    } else {
      // Write the bitcode contents to the temporary file.
      {
        std::error_code EC;
        raw_fd_ostream BitcodeFile(BitcodeFileName, EC, sys::fs::F_None);
        if (EC) {
          errs() << "error: unable to open temporary file.\n";
          return true;
        }
        WriteBitcodeToFile(*AuxModule, BitcodeFile);
      }

      bool Failed = sys::ExecuteAndWait(ClangBinary.get(), ClangArgs);

      // Remove bitcode file.
      sys::fs::remove(BitcodeFileName);

      if (Failed) {
        errs() << "error: incremental linking by external tool failed.\n";
        return true;
      }
    }

    return false;
  }

/// getOrInsertFnSpecificMDNode - Return a NameMDNode that is suitable
/// to hold function specific information.
NamedMDNode *llvm::getOrInsertFnSpecificMDNode(Module &M, DISubprogram Fn) {
  SmallString<32> Name;
  fixupSubprogramName(Fn, Name);
  return M.getOrInsertNamedMetadata(Name.str());
}

/// EmitMatcher - Emit bytes for the specified matcher and return
/// the number of bytes emitted.
unsigned MatcherTableEmitter::
EmitMatcher(const Matcher *N, unsigned Indent, unsigned CurrentIdx,
            raw_ostream &OS) {
  OS.indent(Indent*2);

  switch (N->getKind()) {
  case Matcher::Scope: {
    const ScopeMatcher *SM = cast<ScopeMatcher>(N);
    assert(SM->getNext() == nullptr && "Shouldn't have next after scope");

    unsigned StartIdx = CurrentIdx;

    // Emit all of the children.
    for (unsigned i = 0, e = SM->getNumChildren(); i != e; ++i) {
      if (i == 0) {
        OS << "OPC_Scope, ";
        ++CurrentIdx;
      } else  {
        if (!OmitComments) {
          OS << "/*" << format_decimal(CurrentIdx, IndexWidth) << "*/";
          OS.indent(Indent*2) << "/*Scope*/ ";
        } else
          OS.indent(Indent*2);
      }

      // We need to encode the child and the offset of the failure code before
      // emitting either of them.  Handle this by buffering the output into a
      // string while we get the size.  Unfortunately, the offset of the
      // children depends on the VBR size of the child, so for large children we
      // have to iterate a bit.
      SmallString<128> TmpBuf;
      unsigned ChildSize = 0;
      unsigned VBRSize = 0;
      do {
        VBRSize = GetVBRSize(ChildSize);

        TmpBuf.clear();
        raw_svector_ostream OS(TmpBuf);
        ChildSize = EmitMatcherList(SM->getChild(i), Indent+1,
                                    CurrentIdx+VBRSize, OS);
      } while (GetVBRSize(ChildSize) != VBRSize);

      assert(ChildSize != 0 && "Should not have a zero-sized child!");

      CurrentIdx += EmitVBRValue(ChildSize, OS);
      if (!OmitComments) {
        OS << "/*->" << CurrentIdx+ChildSize << "*/";

        if (i == 0)
          OS << " // " << SM->getNumChildren() << " children in Scope";
      }

      OS << '\n' << TmpBuf;
      CurrentIdx += ChildSize;
    }

    // Emit a zero as a sentinel indicating end of 'Scope'.
    if (!OmitComments)
      OS << "/*" << format_decimal(CurrentIdx, IndexWidth) << "*/";
    OS.indent(Indent*2) << "0, ";
    if (!OmitComments)
      OS << "/*End of Scope*/";
    OS << '\n';
    return CurrentIdx - StartIdx + 1;
  }

  case Matcher::RecordNode:
    OS << "OPC_RecordNode,";
    if (!OmitComments)
      OS << " // #"
         << cast<RecordMatcher>(N)->getResultNo() << " = "
         << cast<RecordMatcher>(N)->getWhatFor();
    OS << '\n';
    return 1;

  case Matcher::RecordChild:
    OS << "OPC_RecordChild" << cast<RecordChildMatcher>(N)->getChildNo()
       << ',';
    if (!OmitComments)
      OS << " // #"
         << cast<RecordChildMatcher>(N)->getResultNo() << " = "
         << cast<RecordChildMatcher>(N)->getWhatFor();
    OS << '\n';
    return 1;

  case Matcher::RecordMemRef:
    OS << "OPC_RecordMemRef,\n";
    return 1;

  case Matcher::CaptureGlueInput:
    OS << "OPC_CaptureGlueInput,\n";
    return 1;

  case Matcher::MoveChild: {
    const auto *MCM = cast<MoveChildMatcher>(N);

    OS << "OPC_MoveChild";
    // Handle the specialized forms.
//.........这里部分代码省略.........

std::string Twine::str() const {
  SmallString<256> Vec;
  toVector(Vec);
  return std::string(Vec.begin(), Vec.end());
}

/// Returns true for failure to resolve.
static bool passCursorInfoForDecl(const ValueDecl *VD,
                                  const Module *MainModule,
                                  const Type Ty,
                                  bool IsRef,
                                  Optional<unsigned> OrigBufferID,
                                  SwiftLangSupport &Lang,
                                  const CompilerInvocation &Invok,
                            ArrayRef<ImmutableTextSnapshotRef> PreviousASTSnaps,
                             std::function<void(const CursorInfo &)> Receiver) {
  if (AvailableAttr::isUnavailable(VD))
    return true;

  SmallString<64> SS;

  unsigned NameBegin = SS.size();
  {
    llvm::raw_svector_ostream OS(SS);
    SwiftLangSupport::printDisplayName(VD, OS);
  }
  unsigned NameEnd = SS.size();

  unsigned USRBegin = SS.size();
  {
    llvm::raw_svector_ostream OS(SS);
    SwiftLangSupport::printUSR(VD, OS);
  }
  unsigned USREnd = SS.size();

  unsigned TypenameBegin = SS.size();
  if (VD->hasType()) {
    llvm::raw_svector_ostream OS(SS);
    VD->getType().print(OS);
  }
  unsigned TypenameEnd = SS.size();

  unsigned DocCommentBegin = SS.size();
  {
    llvm::raw_svector_ostream OS(SS);
    ide::getDocumentationCommentAsXML(VD, OS);
  }
  unsigned DocCommentEnd = SS.size();

  unsigned DeclBegin = SS.size();
  {
    llvm::raw_svector_ostream OS(SS);
    printAnnotatedDeclaration(VD, OS);
  }
  unsigned DeclEnd = SS.size();

  SmallVector<std::pair<unsigned, unsigned>, 4> OverUSROffs;

  ide::walkOverriddenDecls(VD,
    [&](llvm::PointerUnion<const ValueDecl*, const clang::NamedDecl*> D) {
      unsigned OverUSRBegin = SS.size();
      {
        llvm::raw_svector_ostream OS(SS);
        if (auto VD = D.dyn_cast<const ValueDecl*>()) {
          if (SwiftLangSupport::printUSR(VD, OS))
            return;
        } else {
          llvm::SmallString<128> Buf;
          if (clang::index::generateUSRForDecl(
              D.get<const clang::NamedDecl*>(), Buf))
            return;
          OS << Buf.str();
        }
      }
      unsigned OverUSREnd = SS.size();
      OverUSROffs.push_back(std::make_pair(OverUSRBegin, OverUSREnd));
  });

  SmallVector<std::pair<unsigned, unsigned>, 4> RelDeclOffs;
  walkRelatedDecls(VD, [&](const ValueDecl *RelatedDecl, bool DuplicateName) {
    unsigned RelatedDeclBegin = SS.size();
    {
      llvm::raw_svector_ostream OS(SS);
      OS<<"<RelatedName usr=\"";
      SwiftLangSupport::printUSR(RelatedDecl, OS);
      OS<<"\">";
      if (isa<AbstractFunctionDecl>(RelatedDecl) && DuplicateName) {
        // Related decls are generally overloads, so print parameter types to
        // differentiate them.
        PrintOptions PO;
        PO.SkipAttributes = true;
        PO.SkipIntroducerKeywords = true;
        PO.ArgAndParamPrinting = PrintOptions::ArgAndParamPrintingMode::ArgumentOnly;
        XMLEscapingPrinter Printer(OS);
        RelatedDecl->print(Printer, PO);
      } else {
        llvm::SmallString<128> Buf;
        {
          llvm::raw_svector_ostream OSBuf(Buf);
          SwiftLangSupport::printDisplayName(RelatedDecl, OSBuf);
        }
        llvm::markup::appendWithXMLEscaping(OS, Buf);
      }
      OS<<"</RelatedName>";
    }
    unsigned RelatedDeclEnd = SS.size();
//.........这里部分代码省略.........

/// @brief Get the length of the string that represents @p num in Radix
///        including the leading 0x or 0 for hexadecimal and octal respectively.
static size_t getNumLengthAsString(uint64_t num) {
  APInt conv(64, num);
  SmallString<32> result;
  conv.toString(result, Radix, false, true);
  return result.size();
}

static MCSectionELF *
selectELFSectionForGlobal(MCContext &Ctx, const GlobalValue *GV,
                          SectionKind Kind, Mangler &Mang,
                          const TargetMachine &TM, bool EmitUniqueSection,
                          unsigned Flags, unsigned *NextUniqueID) {
  unsigned EntrySize = 0;
  if (Kind.isMergeableCString()) {
    if (Kind.isMergeable2ByteCString()) {
      EntrySize = 2;
    } else if (Kind.isMergeable4ByteCString()) {
      EntrySize = 4;
    } else {
      EntrySize = 1;
      assert(Kind.isMergeable1ByteCString() && "unknown string width");
    }
  } else if (Kind.isMergeableConst()) {
    if (Kind.isMergeableConst4()) {
      EntrySize = 4;
    } else if (Kind.isMergeableConst8()) {
      EntrySize = 8;
    } else {
      assert(Kind.isMergeableConst16() && "unknown data width");
      EntrySize = 16;
    }
  }

  StringRef Group = "";
  if (const Comdat *C = getELFComdat(GV)) {
    Flags |= ELF::SHF_GROUP;
    Group = C->getName();
  }

  bool UniqueSectionNames = TM.getUniqueSectionNames();
  SmallString<128> Name;
  if (Kind.isMergeableCString()) {
    // We also need alignment here.
    // FIXME: this is getting the alignment of the character, not the
    // alignment of the global!
    unsigned Align = GV->getParent()->getDataLayout().getPreferredAlignment(
        cast<GlobalVariable>(GV));

    std::string SizeSpec = ".rodata.str" + utostr(EntrySize) + ".";
    Name = SizeSpec + utostr(Align);
  } else if (Kind.isMergeableConst()) {
    Name = ".rodata.cst";
    Name += utostr(EntrySize);
  } else {
    Name = getSectionPrefixForGlobal(Kind);
  }

  if (EmitUniqueSection && UniqueSectionNames) {
    Name.push_back('.');
    TM.getNameWithPrefix(Name, GV, Mang, true);
  }
  unsigned UniqueID = ~0;
  if (EmitUniqueSection && !UniqueSectionNames) {
    UniqueID = *NextUniqueID;
    (*NextUniqueID)++;
  }
  return Ctx.getELFSection(Name, getELFSectionType(Name, Kind), Flags,
                           EntrySize, Group, UniqueID);
}

MCSymbol *MCContext::GetOrCreateSymbol(const Twine &Name) {
  SmallString<128> NameSV;
  Name.toVector(NameSV);
  return GetOrCreateSymbol(NameSV.str());
}

/// PasteTokens - Tok is the LHS of a ## operator, and CurToken is the ##
/// operator.  Read the ## and RHS, and paste the LHS/RHS together.  If there
/// are more ## after it, chomp them iteratively.  Return the result as Tok.
/// If this returns true, the caller should immediately return the token.
bool TokenLexer::PasteTokens(Token &Tok) {
  SmallString<128> Buffer;
  const char *ResultTokStrPtr = nullptr;
  SourceLocation StartLoc = Tok.getLocation();
  SourceLocation PasteOpLoc;
  do {
    // Consume the ## operator if any.
    PasteOpLoc = Tokens[CurToken].getLocation();
    if (Tokens[CurToken].is(tok::hashhash))
      ++CurToken;
    assert(!isAtEnd() && "No token on the RHS of a paste operator!");

    // Get the RHS token.
    const Token &RHS = Tokens[CurToken];

    // Allocate space for the result token.  This is guaranteed to be enough for
    // the two tokens.
    Buffer.resize(Tok.getLength() + RHS.getLength());

    // Get the spelling of the LHS token in Buffer.
    const char *BufPtr = &Buffer[0];
    bool Invalid = false;
    unsigned LHSLen = PP.getSpelling(Tok, BufPtr, &Invalid);
    if (BufPtr != &Buffer[0])   // Really, we want the chars in Buffer!
      memcpy(&Buffer[0], BufPtr, LHSLen);
    if (Invalid)
      return true;

    BufPtr = Buffer.data() + LHSLen;
    unsigned RHSLen = PP.getSpelling(RHS, BufPtr, &Invalid);
    if (Invalid)
      return true;
    if (RHSLen && BufPtr != &Buffer[LHSLen])
      // Really, we want the chars in Buffer!
      memcpy(&Buffer[LHSLen], BufPtr, RHSLen);

    // Trim excess space.
    Buffer.resize(LHSLen+RHSLen);

    // Plop the pasted result (including the trailing newline and null) into a
    // scratch buffer where we can lex it.
    Token ResultTokTmp;
    ResultTokTmp.startToken();

    // Claim that the tmp token is a string_literal so that we can get the
    // character pointer back from CreateString in getLiteralData().
    ResultTokTmp.setKind(tok::string_literal);
    PP.CreateString(Buffer, ResultTokTmp);
    SourceLocation ResultTokLoc = ResultTokTmp.getLocation();
    ResultTokStrPtr = ResultTokTmp.getLiteralData();

    // Lex the resultant pasted token into Result.
    Token Result;

    if (Tok.isAnyIdentifier() && RHS.isAnyIdentifier()) {
      // Common paste case: identifier+identifier = identifier.  Avoid creating
      // a lexer and other overhead.
      PP.IncrementPasteCounter(true);
      Result.startToken();
      Result.setKind(tok::raw_identifier);
      Result.setRawIdentifierData(ResultTokStrPtr);
      Result.setLocation(ResultTokLoc);
      Result.setLength(LHSLen+RHSLen);
    } else {
      PP.IncrementPasteCounter(false);

      assert(ResultTokLoc.isFileID() &&
             "Should be a raw location into scratch buffer");
      SourceManager &SourceMgr = PP.getSourceManager();
      FileID LocFileID = SourceMgr.getFileID(ResultTokLoc);

      bool Invalid = false;
      const char *ScratchBufStart
        = SourceMgr.getBufferData(LocFileID, &Invalid).data();
      if (Invalid)
        return false;

      // Make a lexer to lex this string from.  Lex just this one token.
      // Make a lexer object so that we lex and expand the paste result.
      Lexer TL(SourceMgr.getLocForStartOfFile(LocFileID),
               PP.getLangOpts(), ScratchBufStart,
               ResultTokStrPtr, ResultTokStrPtr+LHSLen+RHSLen);

      // Lex a token in raw mode.  This way it won't look up identifiers
      // automatically, lexing off the end will return an eof token, and
      // warnings are disabled.  This returns true if the result token is the
      // entire buffer.
      bool isInvalid = !TL.LexFromRawLexer(Result);

      // If we got an EOF token, we didn't form even ONE token.  For example, we
      // did "/ ## /" to get "//".
      isInvalid |= Result.is(tok::eof);

      // If pasting the two tokens didn't form a full new token, this is an
      // error.  This occurs with "x ## +"  and other stuff.  Return with Tok
      // unmodified and with RHS as the next token to lex.
//.........这里部分代码省略.........

/// This method runs "Program", capturing the output of the program to a file,
/// returning the filename of the file.  A recommended filename may be
/// optionally specified.
Expected<std::string> BugDriver::executeProgram(const Module &Program,
                                                std::string OutputFile,
                                                std::string BitcodeFile,
                                                const std::string &SharedObj,
                                                AbstractInterpreter *AI) const {
  if (!AI)
    AI = Interpreter;
  assert(AI && "Interpreter should have been created already!");
  if (BitcodeFile.empty()) {
    // Emit the program to a bitcode file...
    auto File =
        sys::fs::TempFile::create(OutputPrefix + "-test-program-%%%%%%%.bc");
    if (!File) {
      errs() << ToolName
             << ": Error making unique filename: " << toString(File.takeError())
             << "!\n";
      exit(1);
    }
    DiscardTemp Discard{*File};
    BitcodeFile = File->TmpName;

    if (writeProgramToFile(File->FD, Program)) {
      errs() << ToolName << ": Error emitting bitcode to file '" << BitcodeFile
             << "'!\n";
      exit(1);
    }
  }

  if (OutputFile.empty())
    OutputFile = OutputPrefix + "-execution-output-%%%%%%%";

  // Check to see if this is a valid output filename...
  SmallString<128> UniqueFile;
  std::error_code EC = sys::fs::createUniqueFile(OutputFile, UniqueFile);
  if (EC) {
    errs() << ToolName << ": Error making unique filename: " << EC.message()
           << "\n";
    exit(1);
  }
  OutputFile = UniqueFile.str();

  // Figure out which shared objects to run, if any.
  std::vector<std::string> SharedObjs(AdditionalSOs);
  if (!SharedObj.empty())
    SharedObjs.push_back(SharedObj);

  Expected<int> RetVal = AI->ExecuteProgram(BitcodeFile, InputArgv, InputFile,
                                            OutputFile, AdditionalLinkerArgs,
                                            SharedObjs, Timeout, MemoryLimit);
  if (Error E = RetVal.takeError())
    return std::move(E);

  if (*RetVal == -1) {
    errs() << "<timeout>";
    static bool FirstTimeout = true;
    if (FirstTimeout) {
      outs()
          << "\n"
             "*** Program execution timed out!  This mechanism is designed to "
             "handle\n"
             "    programs stuck in infinite loops gracefully.  The -timeout "
             "option\n"
             "    can be used to change the timeout threshold or disable it "
             "completely\n"
             "    (with -timeout=0).  This message is only displayed once.\n";
      FirstTimeout = false;
    }
  }

  if (AppendProgramExitCode) {
    std::ofstream outFile(OutputFile.c_str(), std::ios_base::app);
    outFile << "exit " << *RetVal << '\n';
    outFile.close();
  }

  // Return the filename we captured the output to.
  return OutputFile;
}