C++ SmallString::resize方法代码示例

void StringTableBuilder::write(raw_ostream &OS) const {
  assert(isFinalized());
  SmallString<0> Data;
  Data.resize(getSize());
  write((uint8_t *)&Data[0]);
  OS << Data;
}

MCSymbol *MCContext::createSymbol(StringRef Name, bool AlwaysAddSuffix,
                                  bool CanBeUnnamed) {
  if (CanBeUnnamed && !UseNamesOnTempLabels)
    return createSymbolImpl(nullptr, true);

  // Determine whether this is an user writter assembler temporary or normal
  // label, if used.
  bool IsTemporary = CanBeUnnamed;
  if (AllowTemporaryLabels && !IsTemporary)
    IsTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());

  SmallString<128> NewName = Name;
  bool AddSuffix = AlwaysAddSuffix;
  unsigned &NextUniqueID = NextID[Name];
  for (;;) {
    if (AddSuffix) {
      NewName.resize(Name.size());
      raw_svector_ostream(NewName) << NextUniqueID++;
    }
    auto NameEntry = UsedNames.insert(std::make_pair(NewName, true));
    if (NameEntry.second) {
      // Ok, we found a name. Have the MCSymbol object itself refer to the copy
      // of the string that is embedded in the UsedNames entry.
      return createSymbolImpl(&*NameEntry.first, IsTemporary);
    }
    assert(IsTemporary && "Cannot rename non-temporary symbols");
    AddSuffix = true;
  }
  llvm_unreachable("Infinite loop");
}

// getSpelling - Get the spelling of the AsmTok token.
static StringRef getSpelling(Sema &SemaRef, Token AsmTok) {
  StringRef Asm;
  SmallString<512> TokenBuf;
  TokenBuf.resize(512);
  bool StringInvalid = false;
  Asm = SemaRef.PP.getSpelling(AsmTok, TokenBuf, &StringInvalid);
  assert (!StringInvalid && "Expected valid string!");
  return Asm;
}

// This function is an adaptation from StringLiteral::getLocationOfByte in llvm-3.7.1\src\tools\clang\lib\AST\Expr.cpp
std::vector<std::string>
splitStringLiteral(StringLiteral *S, const SourceManager &SM, const LangOptions &Features, const TargetInfo &Target)
{
    // Loop over all of the tokens in this string until we find the one that
    // contains the byte we're looking for.
    unsigned TokNo = 0;

    std::vector<std::string> result;
    for (TokNo = 0; TokNo < S->getNumConcatenated(); ++TokNo)
    {
        SourceLocation StrTokLoc = S->getStrTokenLoc(TokNo);

        // Get the spelling of the string so that we can get the data that makes up
        // the string literal, not the identifier for the macro it is potentially
        // expanded through.
        SourceLocation StrTokSpellingLoc = SM.getSpellingLoc(StrTokLoc);

        // Re-lex the token to get its length and original spelling.
        std::pair<FileID, unsigned> LocInfo = SM.getDecomposedLoc(StrTokSpellingLoc);
        bool Invalid = false;
        StringRef Buffer = SM.getBufferData(LocInfo.first, &Invalid);
        if (Invalid)
            continue; // We ignore this part

        const char *StrData = Buffer.data() + LocInfo.second;

        // Create a lexer starting at the beginning of this token.
        Lexer TheLexer(SM.getLocForStartOfFile(LocInfo.first), Features,
            Buffer.begin(), StrData, Buffer.end());
        Token TheTok;
        TheLexer.LexFromRawLexer(TheTok);
        if (TheTok.isAnyIdentifier())
        {
            // It should not be, since we are parsing inside a string literal, but it can happen with special macros such as __func__
            // of __PRETTY_FUNCTION__ that are not resolved at this time. In that case, we just ignore them...
            continue;
        }
        // Get the spelling of the token.
        SmallString<32> SpellingBuffer;
        SpellingBuffer.resize(TheTok.getLength());

        bool StringInvalid = false;
        const char *SpellingPtr = &SpellingBuffer[0];
        unsigned TokLen = Lexer::getSpelling(TheTok, SpellingPtr, SM, Features, &StringInvalid);
        if (StringInvalid)
            continue;

        const char *SpellingStart = SpellingPtr;
        const char *SpellingEnd = SpellingPtr + TokLen;
        result.push_back(std::string(SpellingStart, SpellingEnd));

    }
    return result;
}

MCSymbol *MCContext::CreateSymbol(StringRef Name) {
  // Determine whether this is an assembler temporary or normal label, if used.
  bool isTemporary = false;
  if (AllowTemporaryLabels)
    isTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());

  StringMapEntry<bool> *NameEntry = &UsedNames.GetOrCreateValue(Name);
  if (NameEntry->getValue()) {
    assert(isTemporary && "Cannot rename non-temporary symbols");
    SmallString<128> NewName = Name;
    do {
      NewName.resize(Name.size());
      raw_svector_ostream(NewName) << NextUniqueID++;
      NameEntry = &UsedNames.GetOrCreateValue(NewName);
    } while (NameEntry->getValue());
  }
  NameEntry->setValue(true);

  // Ok, the entry doesn't already exist.  Have the MCSymbol object itself refer
  // to the copy of the string that is embedded in the UsedNames entry.
  MCSymbol *Result = new (*this) MCSymbol(NameEntry->getKey(), isTemporary);

  return Result;
}

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:
    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::Win32:
    switch (triple.getEnvironment()) {
    default: llvm_unreachable("Include management is handled in the driver.");
    case llvm::Triple::Cygnus:
      AddPath("/usr/include/w32api", System, false);
      break;
    case llvm::Triple::GNU:
      // 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());
//.........这里部分代码省略.........

/// 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 = 0;
  SourceLocation StartLoc = Tok.getLocation();
  SourceLocation PasteOpLoc;
  do {
    // Consume the ## operator.
    PasteOpLoc = Tokens[CurToken].getLocation();
    ++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[LHSLen];
    unsigned RHSLen = PP.getSpelling(RHS, BufPtr, &Invalid);
    if (Invalid)
      return true;
    if (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[0], Buffer.size(), 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.
      if (isInvalid) {
        // Test for the Microsoft extension of /##/ turning into // here on the
//.........这里部分代码省略.........

C2::ExprResult C2Sema::ActOnNumericConstant(const Token& Tok) {
#ifdef SEMA_DEBUG
    std::cerr << COL_SEMA << "SEMA: numeric constant" << ANSI_NORMAL"\n";
#endif
    // Fast path for a single digit (which is quite common).  A single digit
    // cannot have a trigraph, escaped newline, radix prefix, or suffix.
    if (Tok.getLength() == 1) {
        const char Val = PP.getSpellingOfSingleCharacterNumericConstant(Tok);
        return ActOnIntegerConstant(Tok.getLocation(), Val-'0');
    }
  SmallString<128> SpellingBuffer;
  // NumericLiteralParser wants to overread by one character.  Add padding to
  // the buffer in case the token is copied to the buffer.  If getSpelling()
  // returns a StringRef to the memory buffer, it should have a null char at
  // the EOF, so it is also safe.
  SpellingBuffer.resize(Tok.getLength() + 1);

  // Get the spelling of the token, which eliminates trigraphs, etc.
  bool Invalid = false;
  StringRef TokSpelling = PP.getSpelling(Tok, SpellingBuffer, &Invalid);
  if (Invalid)
    return ExprError();

  NumericLiteralParser Literal(TokSpelling, Tok.getLocation(), PP);
  if (Literal.hadError)
    return ExprError();

    if (Literal.hasUDSuffix()) {
        assert(0 && "HUH?");
    }

    Expr* Res;

    if (Literal.isFloatingLiteral()) {
        // clang::Sema::BuildFloatingLiteral()
        // TEMP Hardcoded
        const llvm::fltSemantics& Format = llvm::APFloat::IEEEsingle;
        APFloat Val(Format);

        APFloat::opStatus result = Literal.GetFloatValue(Val);
      // Overflow is always an error, but underflow is only an error if
      // we underflowed to zero (APFloat reports denormals as underflow).
      if ((result & APFloat::opOverflow) ||
          ((result & APFloat::opUnderflow) && Val.isZero())) {
        assert(0 && "TODO");
#if 0
        unsigned diagnostic;
        SmallString<20> buffer;
        if (result & APFloat::opOverflow) {
          diagnostic = diag::warn_float_overflow;
          APFloat::getLargest(Format).toString(buffer);
        } else {
          diagnostic = diag::warn_float_underflow;
          APFloat::getSmallest(Format).toString(buffer);
        }

        Diag(Tok.getLocation(), diagnostic)
          << Ty
          << StringRef(buffer.data(), buffer.size());
#endif
      }

      //bool isExact = (result == APFloat::opOK);
      //return FloatingLiteral::Create(S.Context, Val, isExact, Ty, Loc);
        Res = new FloatingLiteral(Tok.getLocation(), Val);

    } else if (!Literal.isIntegerLiteral()) {
        return ExprError();
    } else {
        QualType ty;

        const unsigned MaxWidth = 64; // for now limit to 64 bits
        llvm::APInt ResultVal(MaxWidth, 0);
        if (Literal.GetIntegerValue(ResultVal)) {
            Diag(Tok.getLocation(), diag::err_integer_literal_too_large) << 1;
        } else {
#if 0
            // Octal, Hexadecimal, and integers with a U suffix are allowed to
            // be an unsigned.
            bool AllowUnsigned = Literal.isUnsigned || Literal.getRadix() != 10;

            // Check from smallest to largest, picking the smallest type we can.
            unsigned Width = 0;
          if (!Literal.isLong && !Literal.isLongLong) {
            // Are int/unsigned possibilities?
            unsigned IntSize = 64;

            // Does it fit in a unsigned?
            if (ResultVal.isIntN(IntSize)) {
              // Does it fit in a signed int?
#if 0
              if (!Literal.isUnsigned && ResultVal[IntSize-1] == 0)
                Ty = Context.IntTy;
              else if (AllowUnsigned)
                Ty = Context.UnsignedIntTy;
#endif
              Width = IntSize;
            }
          }

//.........这里部分代码省略.........

/// StringifyArgument - Implement C99 6.10.3.2p2, converting a sequence of
/// tokens into the literal string token that should be produced by the C #
/// preprocessor operator.  If Charify is true, then it should be turned into
/// a character literal for the Microsoft charize (#@) extension.
///
Token MacroArgs::StringifyArgument(const Token *ArgToks,
                                   Preprocessor &PP, bool Charify,
                                   SourceLocation ExpansionLocStart,
                                   SourceLocation ExpansionLocEnd) {
  Token Tok;
  Tok.startToken();
  Tok.setKind(Charify ? tok::char_constant : tok::string_literal);

  const Token *ArgTokStart = ArgToks;

  // Stringify all the tokens.
  SmallString<128> Result;
  Result += "\"";

  bool isFirst = true;
  for (; ArgToks->isNot(tok::eof); ++ArgToks) {
    const Token &Tok = *ArgToks;
    if (!isFirst && (Tok.hasLeadingSpace() || Tok.isAtStartOfLine()))
      Result += ' ';
    isFirst = false;

    // If this is a string or character constant, escape the token as specified
    // by 6.10.3.2p2.
    if (tok::isStringLiteral(Tok.getKind()) || // "foo", u8R"x(foo)x"_bar, etc.
        Tok.is(tok::char_constant) ||          // 'x'
        Tok.is(tok::wide_char_constant) ||     // L'x'.
        Tok.is(tok::utf8_char_constant) ||     // u8'x'.
        Tok.is(tok::utf16_char_constant) ||    // u'x'.
        Tok.is(tok::utf32_char_constant)) {    // U'x'.
      bool Invalid = false;
      std::string TokStr = PP.getSpelling(Tok, &Invalid);
      if (!Invalid) {
        std::string Str = Lexer::Stringify(TokStr);
        Result.append(Str.begin(), Str.end());
      }
    } else if (Tok.is(tok::code_completion)) {
      PP.CodeCompleteNaturalLanguage();
    } else {
      // Otherwise, just append the token.  Do some gymnastics to get the token
      // in place and avoid copies where possible.
      unsigned CurStrLen = Result.size();
      Result.resize(CurStrLen+Tok.getLength());
      const char *BufPtr = Result.data() + CurStrLen;
      bool Invalid = false;
      unsigned ActualTokLen = PP.getSpelling(Tok, BufPtr, &Invalid);

      if (!Invalid) {
        // If getSpelling returned a pointer to an already uniqued version of
        // the string instead of filling in BufPtr, memcpy it onto our string.
        if (ActualTokLen && BufPtr != &Result[CurStrLen])
          memcpy(&Result[CurStrLen], BufPtr, ActualTokLen);

        // If the token was dirty, the spelling may be shorter than the token.
        if (ActualTokLen != Tok.getLength())
          Result.resize(CurStrLen+ActualTokLen);
      }
    }
  }

  // If the last character of the string is a \, and if it isn't escaped, this
  // is an invalid string literal, diagnose it as specified in C99.
  if (Result.back() == '\\') {
    // Count the number of consecutive \ characters.  If even, then they are
    // just escaped backslashes, otherwise it's an error.
    unsigned FirstNonSlash = Result.size()-2;
    // Guaranteed to find the starting " if nothing else.
    while (Result[FirstNonSlash] == '\\')
      --FirstNonSlash;
    if ((Result.size()-1-FirstNonSlash) & 1) {
      // Diagnose errors for things like: #define F(X) #X   /   F(\)
      PP.Diag(ArgToks[-1], diag::pp_invalid_string_literal);
      Result.pop_back();  // remove one of the \'s.
    }
  }
  Result += '"';

  // If this is the charify operation and the result is not a legal character
  // constant, diagnose it.
  if (Charify) {
    // First step, turn double quotes into single quotes:
    Result[0] = '\'';
    Result[Result.size()-1] = '\'';

    // Check for bogus character.
    bool isBad = false;
    if (Result.size() == 3)
      isBad = Result[1] == '\'';   // ''' is not legal. '\' already fixed above.
    else
      isBad = (Result.size() != 4 || Result[1] != '\\');  // Not '\x'

    if (isBad) {
      PP.Diag(ArgTokStart[0], diag::err_invalid_character_to_charify);
      Result = "' '";  // Use something arbitrary, but legal.
    }
  }
//.........这里部分代码省略.........

/// \brief Parse a header declaration.
///
///   header-declaration:
///     'umbrella'[opt] 'header' string-literal
void ModuleMapParser::parseHeaderDecl(SourceLocation UmbrellaLoc) {
  assert(Tok.is(MMToken::HeaderKeyword));
  consumeToken();

  bool Umbrella = UmbrellaLoc.isValid();
  
  // Parse the header name.
  if (!Tok.is(MMToken::StringLiteral)) {
    Diags.Report(Tok.getLocation(), diag::err_mmap_expected_header) 
      << "header";
    HadError = true;
    return;
  }
  std::string FileName = Tok.getString();
  SourceLocation FileNameLoc = consumeToken();
  
  // Check whether we already have an umbrella.
  if (Umbrella && ActiveModule->Umbrella) {
    Diags.Report(FileNameLoc, diag::err_mmap_umbrella_clash)
      << ActiveModule->getFullModuleName();
    HadError = true;
    return;
  }

  // Look for this file.
  const FileEntry *File = 0;
  const FileEntry *BuiltinFile = 0;
  SmallString<128> PathName;
  if (llvm::sys::path::is_absolute(FileName)) {
    PathName = FileName;
    File = SourceMgr.getFileManager().getFile(PathName);
  } else if (const DirectoryEntry *Dir = getOverriddenHeaderSearchDir()) {
    PathName = Dir->getName();
    llvm::sys::path::append(PathName, FileName);
    File = SourceMgr.getFileManager().getFile(PathName);
  } else {
    // Search for the header file within the search directory.
    PathName = Directory->getName();
    unsigned PathLength = PathName.size();
    
    if (ActiveModule->isPartOfFramework()) {
      appendSubframeworkPaths(ActiveModule, PathName);
      
      // Check whether this file is in the public headers.
      llvm::sys::path::append(PathName, "Headers");
      llvm::sys::path::append(PathName, FileName);
      File = SourceMgr.getFileManager().getFile(PathName);
      
      if (!File) {
        // Check whether this file is in the private headers.
        PathName.resize(PathLength);
        llvm::sys::path::append(PathName, "PrivateHeaders");
        llvm::sys::path::append(PathName, FileName);
        File = SourceMgr.getFileManager().getFile(PathName);
      }
    } else {
      // Lookup for normal headers.
      llvm::sys::path::append(PathName, FileName);
      File = SourceMgr.getFileManager().getFile(PathName);
      
      // If this is a system module with a top-level header, this header
      // may have a counterpart (or replacement) in the set of headers
      // supplied by Clang. Find that builtin header.
      if (ActiveModule->IsSystem && !Umbrella && BuiltinIncludeDir &&
          BuiltinIncludeDir != Directory && isBuiltinHeader(FileName)) {
        SmallString<128> BuiltinPathName(BuiltinIncludeDir->getName());
        llvm::sys::path::append(BuiltinPathName, FileName);
        BuiltinFile = SourceMgr.getFileManager().getFile(BuiltinPathName);
        
        // If Clang supplies this header but the underlying system does not,
        // just silently swap in our builtin version. Otherwise, we'll end
        // up adding both (later).
        if (!File && BuiltinFile) {
          File = BuiltinFile;
          BuiltinFile = 0;
        }
      }
    }
  }
  
  // FIXME: We shouldn't be eagerly stat'ing every file named in a module map.
  // Come up with a lazy way to do this.
  if (File) {
    if (const Module *OwningModule = Map.Headers[File]) {
      Diags.Report(FileNameLoc, diag::err_mmap_header_conflict)
        << FileName << OwningModule->getFullModuleName();
      HadError = true;
    } else if (Umbrella) {
      const DirectoryEntry *UmbrellaDir = File->getDir();
      if ((OwningModule = Map.UmbrellaDirs[UmbrellaDir])) {
        Diags.Report(UmbrellaLoc, diag::err_mmap_umbrella_clash)
          << OwningModule->getFullModuleName();
        HadError = true;
      } else {
        // Record this umbrella header.
        Map.setUmbrellaHeader(ActiveModule, File);
//.........这里部分代码省略.........

//.........这里部分代码省略.........
    int64_t AddressDelta;
    if (Address == -1ULL) {
      MS->EmitIntValue(dwarf::DW_LNS_extended_op, 1);
      MS->EmitULEB128IntValue(PointerSize + 1);
      MS->EmitIntValue(dwarf::DW_LNE_set_address, 1);
      MS->EmitIntValue(Row.Address, PointerSize);
      LineSectionSize += 2 + PointerSize + getULEB128Size(PointerSize + 1);
      AddressDelta = 0;
    } else {
      AddressDelta = (Row.Address - Address) / MinInstLength;
    }

    // FIXME: code copied and transformed from MCDwarf.cpp::EmitDwarfLineTable.
    // We should find a way to share this code, but the current compatibility
    // requirement with classic dsymutil makes it hard. Revisit that once this
    // requirement is dropped.

    if (FileNum != Row.File) {
      FileNum = Row.File;
      MS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
      MS->EmitULEB128IntValue(FileNum);
      LineSectionSize += 1 + getULEB128Size(FileNum);
    }
    if (Column != Row.Column) {
      Column = Row.Column;
      MS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
      MS->EmitULEB128IntValue(Column);
      LineSectionSize += 1 + getULEB128Size(Column);
    }

    // FIXME: We should handle the discriminator here, but dsymutil doesn't
    // consider it, thus ignore it for now.

    if (Isa != Row.Isa) {
      Isa = Row.Isa;
      MS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
      MS->EmitULEB128IntValue(Isa);
      LineSectionSize += 1 + getULEB128Size(Isa);
    }
    if (IsStatement != Row.IsStmt) {
      IsStatement = Row.IsStmt;
      MS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
      LineSectionSize += 1;
    }
    if (Row.BasicBlock) {
      MS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
      LineSectionSize += 1;
    }

    if (Row.PrologueEnd) {
      MS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
      LineSectionSize += 1;
    }

    if (Row.EpilogueBegin) {
      MS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
      LineSectionSize += 1;
    }

    int64_t LineDelta = int64_t(Row.Line) - LastLine;
    if (!Row.EndSequence) {
      MCDwarfLineAddr::Encode(*MC, Params, LineDelta, AddressDelta, EncodingOS);
      MS->EmitBytes(EncodingOS.str());
      LineSectionSize += EncodingBuffer.size();
      EncodingBuffer.resize(0);
      Address = Row.Address;
      LastLine = Row.Line;
      RowsSinceLastSequence++;
    } else {
      if (LineDelta) {
        MS->EmitIntValue(dwarf::DW_LNS_advance_line, 1);
        MS->EmitSLEB128IntValue(LineDelta);
        LineSectionSize += 1 + getSLEB128Size(LineDelta);
      }
      if (AddressDelta) {
        MS->EmitIntValue(dwarf::DW_LNS_advance_pc, 1);
        MS->EmitULEB128IntValue(AddressDelta);
        LineSectionSize += 1 + getULEB128Size(AddressDelta);
      }
      MCDwarfLineAddr::Encode(*MC, Params, std::numeric_limits<int64_t>::max(),
                              0, EncodingOS);
      MS->EmitBytes(EncodingOS.str());
      LineSectionSize += EncodingBuffer.size();
      EncodingBuffer.resize(0);
      Address = -1ULL;
      LastLine = FileNum = IsStatement = 1;
      RowsSinceLastSequence = Column = Isa = 0;
    }
  }

  if (RowsSinceLastSequence) {
    MCDwarfLineAddr::Encode(*MC, Params, std::numeric_limits<int64_t>::max(), 0,
                            EncodingOS);
    MS->EmitBytes(EncodingOS.str());
    LineSectionSize += EncodingBuffer.size();
    EncodingBuffer.resize(0);
  }

  MS->EmitLabel(LineEndSym);
}