text: //===- AsmParser.cpp - Parser for Assembly Files --------------------------===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This class implements the parser for assembly files.
  //
  //===----------------------------------------------------------------------===//
  
  #include "llvm/ADT/APFloat.h"
  #include "llvm/ADT/STLExtras.h"
  #include "llvm/ADT/SmallString.h"
  #include "llvm/ADT/StringMap.h"
  #include "llvm/ADT/Twine.h"
  #include "llvm/MC/MCAsmInfo.h"
  #include "llvm/MC/MCContext.h"
  #include "llvm/MC/MCDwarf.h"
  #include "llvm/MC/MCExpr.h"
  #include "llvm/MC/MCInstPrinter.h"
  #include "llvm/MC/MCInstrInfo.h"
  #include "llvm/MC/MCObjectFileInfo.h"
  #include "llvm/MC/MCParser/AsmCond.h"
  #include "llvm/MC/MCParser/AsmLexer.h"
  #include "llvm/MC/MCParser/MCAsmParser.h"
  #include "llvm/MC/MCParser/MCAsmParserUtils.h"
  #include "llvm/MC/MCParser/MCParsedAsmOperand.h"
  #include "llvm/MC/MCParser/MCTargetAsmParser.h"
  #include "llvm/MC/MCRegisterInfo.h"
  #include "llvm/MC/MCSectionMachO.h"
  #include "llvm/MC/MCStreamer.h"
  #include "llvm/MC/MCSymbol.h"
  #include "llvm/MC/MCValue.h"
  #include "llvm/Support/CommandLine.h"
  #include "llvm/Support/ErrorHandling.h"
  #include "llvm/Support/MathExtras.h"
  #include "llvm/Support/MemoryBuffer.h"
  #include "llvm/Support/SourceMgr.h"
  #include "llvm/Support/raw_ostream.h"
  #include <cctype>
  #include <deque>
  #include <set>
  #include <string>
  #include <vector>
  using namespace llvm;
  
  MCAsmParserSemaCallback::~MCAsmParserSemaCallback() {}
  
  namespace {
  /// \brief Helper types for tracking macro definitions.
  typedef std::vector<AsmToken> MCAsmMacroArgument;
  typedef std::vector<MCAsmMacroArgument> MCAsmMacroArguments;
  
  struct MCAsmMacroParameter {
    StringRef Name;
    MCAsmMacroArgument Value;
    bool Required;
    bool Vararg;
  
    MCAsmMacroParameter() : Required(false), Vararg(false) {}
  };
  
  typedef std::vector<MCAsmMacroParameter> MCAsmMacroParameters;
  
  struct MCAsmMacro {
    StringRef Name;
    StringRef Body;
    MCAsmMacroParameters Parameters;
  
  public:
    MCAsmMacro(StringRef N, StringRef B, MCAsmMacroParameters P)
        : Name(N), Body(B), Parameters(std::move(P)) {}
  };
  
  /// \brief Helper class for storing information about an active macro
  /// instantiation.
  struct MacroInstantiation {
    /// The location of the instantiation.
    SMLoc InstantiationLoc;
  
    /// The buffer where parsing should resume upon instantiation completion.
    int ExitBuffer;
  
    /// The location where parsing should resume upon instantiation completion.
    SMLoc ExitLoc;
  
    /// The depth of TheCondStack at the start of the instantiation.
    size_t CondStackDepth;
  
  public:
    MacroInstantiation(SMLoc IL, int EB, SMLoc EL, size_t CondStackDepth);
  };
  
  struct ParseStatementInfo {
    /// \brief The parsed operands from the last parsed statement.
    SmallVector<std::unique_ptr<MCParsedAsmOperand>, 8> ParsedOperands;
  
    /// \brief The opcode from the last parsed instruction.
    unsigned Opcode;
  
    /// \brief Was there an error parsing the inline assembly?
    bool ParseError;
  
    SmallVectorImpl<AsmRewrite> *AsmRewrites;
  
    ParseStatementInfo() : Opcode(~0U), ParseError(false), AsmRewrites(nullptr) {}
    ParseStatementInfo(SmallVectorImpl<AsmRewrite> *rewrites)
      : Opcode(~0), ParseError(false), AsmRewrites(rewrites) {}
  };
  
  /// \brief The concrete assembly parser instance.
  class AsmParser : public MCAsmParser {
    AsmParser(const AsmParser &) = delete;
    void operator=(const AsmParser &) = delete;
  private:
    AsmLexer Lexer;
    MCContext &Ctx;
    MCStreamer &Out;
    const MCAsmInfo &MAI;
    SourceMgr &SrcMgr;
    SourceMgr::DiagHandlerTy SavedDiagHandler;
    void *SavedDiagContext;
    std::unique_ptr<MCAsmParserExtension> PlatformParser;
  
    /// This is the current buffer index we're lexing from as managed by the
    /// SourceMgr object.
    unsigned CurBuffer;
  
    AsmCond TheCondState;
    std::vector<AsmCond> TheCondStack;
  
    /// \brief maps directive names to handler methods in parser
    /// extensions. Extensions register themselves in this map by calling
    /// addDirectiveHandler.
    StringMap<ExtensionDirectiveHandler> ExtensionDirectiveMap;
  
    /// \brief Map of currently defined macros.
    StringMap<MCAsmMacro> MacroMap;
  
    /// \brief Stack of active macro instantiations.
    std::vector<MacroInstantiation*> ActiveMacros;
  
    /// \brief List of bodies of anonymous macros.
    std::deque<MCAsmMacro> MacroLikeBodies;
  
    /// Boolean tracking whether macro substitution is enabled.
    unsigned MacrosEnabledFlag : 1;
  
    /// \brief Keeps track of how many .macro's have been instantiated.
    unsigned NumOfMacroInstantiations;
  
    /// Flag tracking whether any errors have been encountered.
    unsigned HadError : 1;
  
    /// The values from the last parsed cpp hash file line comment if any.
    StringRef CppHashFilename;
    int64_t CppHashLineNumber;
    SMLoc CppHashLoc;
    unsigned CppHashBuf;
    /// When generating dwarf for assembly source files we need to calculate the
    /// logical line number based on the last parsed cpp hash file line comment
    /// and current line. Since this is slow and messes up the SourceMgr's
    /// cache we save the last info we queried with SrcMgr.FindLineNumber().
    SMLoc LastQueryIDLoc;
    unsigned LastQueryBuffer;
    unsigned LastQueryLine;
  
    /// AssemblerDialect. ~OU means unset value and use value provided by MAI.
    unsigned AssemblerDialect;
  
    /// \brief is Darwin compatibility enabled?
    bool IsDarwin;
  
    /// \brief Are we parsing ms-style inline assembly?
    bool ParsingInlineAsm;
  
  public:
    AsmParser(SourceMgr &SM, MCContext &Ctx, MCStreamer &Out,
              const MCAsmInfo &MAI);
    ~AsmParser() override;
  
    bool Run(bool NoInitialTextSection, bool NoFinalize = false) override;
  
    void addDirectiveHandler(StringRef Directive,
                             ExtensionDirectiveHandler Handler) override {
      ExtensionDirectiveMap[Directive] = Handler;
    }
  
    void addAliasForDirective(StringRef Directive, StringRef Alias) override {
      DirectiveKindMap[Directive] = DirectiveKindMap[Alias];
    }
  
  public:
    /// @name MCAsmParser Interface
    /// {
  
    SourceMgr &getSourceManager() override { return SrcMgr; }
    MCAsmLexer &getLexer() override { return Lexer; }
    MCContext &getContext() override { return Ctx; }
    MCStreamer &getStreamer() override { return Out; }
    unsigned getAssemblerDialect() override {
      if (AssemblerDialect == ~0U)
        return MAI.getAssemblerDialect();
      else
        return AssemblerDialect;
    }
    void setAssemblerDialect(unsigned i) override {
      AssemblerDialect = i;
    }
  
    void Note(SMLoc L, const Twine &Msg,
              ArrayRef<SMRange> Ranges = None) override;
    bool Warning(SMLoc L, const Twine &Msg,
                 ArrayRef<SMRange> Ranges = None) override;
    bool Error(SMLoc L, const Twine &Msg,
               ArrayRef<SMRange> Ranges = None) override;
  
    const AsmToken &Lex() override;
  
    void setParsingInlineAsm(bool V) override { ParsingInlineAsm = V; }
    bool isParsingInlineAsm() override { return ParsingInlineAsm; }
  
    bool parseMSInlineAsm(void *AsmLoc, std::string &AsmString,
                          unsigned &NumOutputs, unsigned &NumInputs,
                          SmallVectorImpl<std::pair<void *,bool> > &OpDecls,
                          SmallVectorImpl<std::string> &Constraints,
                          SmallVectorImpl<std::string> &Clobbers,
                          const MCInstrInfo *MII, const MCInstPrinter *IP,
                          MCAsmParserSemaCallback &SI) override;
  
    bool parseExpression(const MCExpr *&Res);
    bool parseExpression(const MCExpr *&Res, SMLoc &EndLoc) override;
    bool parsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) override;
    bool parseParenExpression(const MCExpr *&Res, SMLoc &EndLoc) override;
    bool parseParenExprOfDepth(unsigned ParenDepth, const MCExpr *&Res,
                               SMLoc &EndLoc) override;
    bool parseAbsoluteExpression(int64_t &Res) override;
  
    /// \brief Parse an identifier or string (as a quoted identifier)
    /// and set \p Res to the identifier contents.
    bool parseIdentifier(StringRef &Res) override;
    void eatToEndOfStatement() override;
  
    void checkForValidSection() override;
    /// }
  
  private:
  
    bool parseStatement(ParseStatementInfo &Info,
                        MCAsmParserSemaCallback *SI);
    void eatToEndOfLine();
    bool parseCppHashLineFilenameComment(SMLoc L);
  
    void checkForBadMacro(SMLoc DirectiveLoc, StringRef Name, StringRef Body,
                          ArrayRef<MCAsmMacroParameter> Parameters);
    bool expandMacro(raw_svector_ostream &OS, StringRef Body,
                     ArrayRef<MCAsmMacroParameter> Parameters,
                     ArrayRef<MCAsmMacroArgument> A, bool EnableAtPseudoVariable,
                     SMLoc L);
  
    /// \brief Are macros enabled in the parser?
    bool areMacrosEnabled() {return MacrosEnabledFlag;}
  
    /// \brief Control a flag in the parser that enables or disables macros.
    void setMacrosEnabled(bool Flag) {MacrosEnabledFlag = Flag;}
  
    /// \brief Lookup a previously defined macro.
    /// \param Name Macro name.
    /// \returns Pointer to macro. NULL if no such macro was defined.
    const MCAsmMacro* lookupMacro(StringRef Name);
  
    /// \brief Define a new macro with the given name and information.
    void defineMacro(StringRef Name, MCAsmMacro Macro);
  
    /// \brief Undefine a macro. If no such macro was defined, it's a no-op.
    void undefineMacro(StringRef Name);
  
    /// \brief Are we inside a macro instantiation?
    bool isInsideMacroInstantiation() {return !ActiveMacros.empty();}
  
    /// \brief Handle entry to macro instantiation.
    ///
    /// \param M The macro.
    /// \param NameLoc Instantiation location.
    bool handleMacroEntry(const MCAsmMacro *M, SMLoc NameLoc);
  
    /// \brief Handle exit from macro instantiation.
    void handleMacroExit();
  
    /// \brief Extract AsmTokens for a macro argument.
    bool parseMacroArgument(MCAsmMacroArgument &MA, bool Vararg);
  
    /// \brief Parse all macro arguments for a given macro.
    bool parseMacroArguments(const MCAsmMacro *M, MCAsmMacroArguments &A);
  
    void printMacroInstantiations();
    void printMessage(SMLoc Loc, SourceMgr::DiagKind Kind, const Twine &Msg,
                      ArrayRef<SMRange> Ranges = None) const {
      SrcMgr.PrintMessage(Loc, Kind, Msg, Ranges);
    }
    static void DiagHandler(const SMDiagnostic &Diag, void *Context);
  
    /// \brief Enter the specified file. This returns true on failure.
    bool enterIncludeFile(const std::string &Filename);
  
    /// \brief Process the specified file for the .incbin directive.
    /// This returns true on failure.
    bool processIncbinFile(const std::string &Filename);
  
    /// \brief Reset the current lexer position to that given by \p Loc. The
    /// current token is not set; clients should ensure Lex() is called
    /// subsequently.
    ///
    /// \param InBuffer If not 0, should be the known buffer id that contains the
    /// location.
    void jumpToLoc(SMLoc Loc, unsigned InBuffer = 0);
  
    /// \brief Parse up to the end of statement and a return the contents from the
    /// current token until the end of the statement; the current token on exit
    /// will be either the EndOfStatement or EOF.
    StringRef parseStringToEndOfStatement() override;
  
    /// \brief Parse until the end of a statement or a comma is encountered,
    /// return the contents from the current token up to the end or comma.
    StringRef parseStringToComma();
  
    bool parseAssignment(StringRef Name, bool allow_redef,
                         bool NoDeadStrip = false);
  
    unsigned getBinOpPrecedence(AsmToken::TokenKind K,
                                MCBinaryExpr::Opcode &Kind);
  
    bool parseBinOpRHS(unsigned Precedence, const MCExpr *&Res, SMLoc &EndLoc);
    bool parseParenExpr(const MCExpr *&Res, SMLoc &EndLoc);
    bool parseBracketExpr(const MCExpr *&Res, SMLoc &EndLoc);
  
    bool parseRegisterOrRegisterNumber(int64_t &Register, SMLoc DirectiveLoc);
  
    // Generic (target and platform independent) directive parsing.
    enum DirectiveKind {
      DK_NO_DIRECTIVE, // Placeholder
      DK_SET, DK_EQU, DK_EQUIV, DK_ASCII, DK_ASCIZ, DK_STRING, DK_BYTE, DK_SHORT,
      DK_RELOC,
      DK_VALUE, DK_2BYTE, DK_LONG, DK_INT, DK_4BYTE, DK_QUAD, DK_8BYTE, DK_OCTA,
      DK_SINGLE, DK_FLOAT, DK_DOUBLE, DK_ALIGN, DK_ALIGN32, DK_BALIGN, DK_BALIGNW,
      DK_BALIGNL, DK_P2ALIGN, DK_P2ALIGNW, DK_P2ALIGNL, DK_ORG, DK_FILL, DK_ENDR,
      DK_BUNDLE_ALIGN_MODE, DK_BUNDLE_LOCK, DK_BUNDLE_UNLOCK,
      DK_ZERO, DK_EXTERN, DK_GLOBL, DK_GLOBAL,
      DK_LAZY_REFERENCE, DK_NO_DEAD_STRIP, DK_SYMBOL_RESOLVER, DK_PRIVATE_EXTERN,
      DK_REFERENCE, DK_WEAK_DEFINITION, DK_WEAK_REFERENCE,
      DK_WEAK_DEF_CAN_BE_HIDDEN, DK_COMM, DK_COMMON, DK_LCOMM, DK_ABORT,
      DK_INCLUDE, DK_INCBIN, DK_CODE16, DK_CODE16GCC, DK_REPT, DK_IRP, DK_IRPC,
      DK_IF, DK_IFEQ, DK_IFGE, DK_IFGT, DK_IFLE, DK_IFLT, DK_IFNE, DK_IFB,
      DK_IFNB, DK_IFC, DK_IFEQS, DK_IFNC, DK_IFNES, DK_IFDEF, DK_IFNDEF,
      DK_IFNOTDEF, DK_ELSEIF, DK_ELSE, DK_ENDIF,
      DK_SPACE, DK_SKIP, DK_FILE, DK_LINE, DK_LOC, DK_STABS,
      DK_CV_FILE, DK_CV_LOC, DK_CV_LINETABLE, DK_CV_INLINE_LINETABLE,
      DK_CV_STRINGTABLE, DK_CV_FILECHECKSUMS,
      DK_CFI_SECTIONS, DK_CFI_STARTPROC, DK_CFI_ENDPROC, DK_CFI_DEF_CFA,
      DK_CFI_DEF_CFA_OFFSET, DK_CFI_ADJUST_CFA_OFFSET, DK_CFI_DEF_CFA_REGISTER,
      DK_CFI_OFFSET, DK_CFI_REL_OFFSET, DK_CFI_PERSONALITY, DK_CFI_LSDA,
      DK_CFI_REMEMBER_STATE, DK_CFI_RESTORE_STATE, DK_CFI_SAME_VALUE,
      DK_CFI_RESTORE, DK_CFI_ESCAPE, DK_CFI_SIGNAL_FRAME, DK_CFI_UNDEFINED,
      DK_CFI_REGISTER, DK_CFI_WINDOW_SAVE,
      DK_MACROS_ON, DK_MACROS_OFF,
      DK_MACRO, DK_EXITM, DK_ENDM, DK_ENDMACRO, DK_PURGEM,
      DK_SLEB128, DK_ULEB128,
      DK_ERR, DK_ERROR, DK_WARNING,
      DK_END
    };
  
    /// \brief Maps directive name --> DirectiveKind enum, for
    /// directives parsed by this class.
    StringMap<DirectiveKind> DirectiveKindMap;
  
    // ".ascii", ".asciz", ".string"
    bool parseDirectiveAscii(StringRef IDVal, bool ZeroTerminated);
    bool parseDirectiveReloc(SMLoc DirectiveLoc); // ".reloc"
    bool parseDirectiveValue(unsigned Size); // ".byte", ".long", ...
    bool parseDirectiveOctaValue(); // ".octa"
    bool parseDirectiveRealValue(const fltSemantics &); // ".single", ...
    bool parseDirectiveFill(); // ".fill"
    bool parseDirectiveZero(); // ".zero"
    // ".set", ".equ", ".equiv"
    bool parseDirectiveSet(StringRef IDVal, bool allow_redef);
    bool parseDirectiveOrg(); // ".org"
    // ".align{,32}", ".p2align{,w,l}"
    bool parseDirectiveAlign(bool IsPow2, unsigned ValueSize);
  
    // ".file", ".line", ".loc", ".stabs"
    bool parseDirectiveFile(SMLoc DirectiveLoc);
    bool parseDirectiveLine();
    bool parseDirectiveLoc();
    bool parseDirectiveStabs();
  
    // ".cv_file", ".cv_loc", ".cv_linetable", "cv_inline_linetable"
    bool parseDirectiveCVFile();
    bool parseDirectiveCVLoc();
    bool parseDirectiveCVLinetable();
    bool parseDirectiveCVInlineLinetable();
    bool parseDirectiveCVStringTable();
    bool parseDirectiveCVFileChecksums();
  
    // .cfi directives
    bool parseDirectiveCFIRegister(SMLoc DirectiveLoc);
    bool parseDirectiveCFIWindowSave();
    bool parseDirectiveCFISections();
    bool parseDirectiveCFIStartProc();
    bool parseDirectiveCFIEndProc();
    bool parseDirectiveCFIDefCfaOffset();
    bool parseDirectiveCFIDefCfa(SMLoc DirectiveLoc);
    bool parseDirectiveCFIAdjustCfaOffset();
    bool parseDirectiveCFIDefCfaRegister(SMLoc DirectiveLoc);
    bool parseDirectiveCFIOffset(SMLoc DirectiveLoc);
    bool parseDirectiveCFIRelOffset(SMLoc DirectiveLoc);
    bool parseDirectiveCFIPersonalityOrLsda(bool IsPersonality);
    bool parseDirectiveCFIRememberState();
    bool parseDirectiveCFIRestoreState();
    bool parseDirectiveCFISameValue(SMLoc DirectiveLoc);
    bool parseDirectiveCFIRestore(SMLoc DirectiveLoc);
    bool parseDirectiveCFIEscape();
    bool parseDirectiveCFISignalFrame();
    bool parseDirectiveCFIUndefined(SMLoc DirectiveLoc);
  
    // macro directives
    bool parseDirectivePurgeMacro(SMLoc DirectiveLoc);
    bool parseDirectiveExitMacro(StringRef Directive);
    bool parseDirectiveEndMacro(StringRef Directive);
    bool parseDirectiveMacro(SMLoc DirectiveLoc);
    bool parseDirectiveMacrosOnOff(StringRef Directive);
  
    // ".bundle_align_mode"
    bool parseDirectiveBundleAlignMode();
    // ".bundle_lock"
    bool parseDirectiveBundleLock();
    // ".bundle_unlock"
    bool parseDirectiveBundleUnlock();
  
    // ".space", ".skip"
    bool parseDirectiveSpace(StringRef IDVal);
  
    // .sleb128 (Signed=true) and .uleb128 (Signed=false)
    bool parseDirectiveLEB128(bool Signed);
  
    /// \brief Parse a directive like ".globl" which
    /// accepts a single symbol (which should be a label or an external).
    bool parseDirectiveSymbolAttribute(MCSymbolAttr Attr);
  
    bool parseDirectiveComm(bool IsLocal); // ".comm" and ".lcomm"
  
    bool parseDirectiveAbort(); // ".abort"
    bool parseDirectiveInclude(); // ".include"
    bool parseDirectiveIncbin(); // ".incbin"
  
    // ".if", ".ifeq", ".ifge", ".ifgt" , ".ifle", ".iflt" or ".ifne"
    bool parseDirectiveIf(SMLoc DirectiveLoc, DirectiveKind DirKind);
    // ".ifb" or ".ifnb", depending on ExpectBlank.
    bool parseDirectiveIfb(SMLoc DirectiveLoc, bool ExpectBlank);
    // ".ifc" or ".ifnc", depending on ExpectEqual.
    bool parseDirectiveIfc(SMLoc DirectiveLoc, bool ExpectEqual);
    // ".ifeqs" or ".ifnes", depending on ExpectEqual.
    bool parseDirectiveIfeqs(SMLoc DirectiveLoc, bool ExpectEqual);
    // ".ifdef" or ".ifndef", depending on expect_defined
    bool parseDirectiveIfdef(SMLoc DirectiveLoc, bool expect_defined);
    bool parseDirectiveElseIf(SMLoc DirectiveLoc); // ".elseif"
    bool parseDirectiveElse(SMLoc DirectiveLoc); // ".else"
    bool parseDirectiveEndIf(SMLoc DirectiveLoc); // .endif
    bool parseEscapedString(std::string &Data) override;
  
    const MCExpr *applyModifierToExpr(const MCExpr *E,
                                      MCSymbolRefExpr::VariantKind Variant);
  
    // Macro-like directives
    MCAsmMacro *parseMacroLikeBody(SMLoc DirectiveLoc);
    void instantiateMacroLikeBody(MCAsmMacro *M, SMLoc DirectiveLoc,
                                  raw_svector_ostream &OS);
    bool parseDirectiveRept(SMLoc DirectiveLoc, StringRef Directive);
    bool parseDirectiveIrp(SMLoc DirectiveLoc);  // ".irp"
    bool parseDirectiveIrpc(SMLoc DirectiveLoc); // ".irpc"
    bool parseDirectiveEndr(SMLoc DirectiveLoc); // ".endr"
  
    // "_emit" or "__emit"
    bool parseDirectiveMSEmit(SMLoc DirectiveLoc, ParseStatementInfo &Info,
                              size_t Len);
  
    // "align"
    bool parseDirectiveMSAlign(SMLoc DirectiveLoc, ParseStatementInfo &Info);
  
    // "end"
    bool parseDirectiveEnd(SMLoc DirectiveLoc);
  
    // ".err" or ".error"
    bool parseDirectiveError(SMLoc DirectiveLoc, bool WithMessage);
  
    // ".warning"
    bool parseDirectiveWarning(SMLoc DirectiveLoc);
  
    void initializeDirectiveKindMap();
  };
  }
  
  namespace llvm {
  
  extern MCAsmParserExtension *createDarwinAsmParser();
  extern MCAsmParserExtension *createELFAsmParser();
  extern MCAsmParserExtension *createCOFFAsmParser();
  
  }
  
  enum { DEFAULT_ADDRSPACE = 0 };
  
  AsmParser::AsmParser(SourceMgr &SM, MCContext &Ctx, MCStreamer &Out,
                       const MCAsmInfo &MAI)
      : Lexer(MAI), Ctx(Ctx), Out(Out), MAI(MAI), SrcMgr(SM),
        PlatformParser(nullptr), CurBuffer(SM.getMainFileID()),
        MacrosEnabledFlag(true), HadError(false), CppHashLineNumber(0),
        AssemblerDialect(~0U), IsDarwin(false), ParsingInlineAsm(false) {
    // Save the old handler.
    SavedDiagHandler = SrcMgr.getDiagHandler();
    SavedDiagContext = SrcMgr.getDiagContext();
    // Set our own handler which calls the saved handler.
    SrcMgr.setDiagHandler(DiagHandler, this);
    Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer());
  
    // Initialize the platform / file format parser.
    switch (Ctx.getObjectFileInfo()->getObjectFileType()) {
    case MCObjectFileInfo::IsCOFF:
      PlatformParser.reset(createCOFFAsmParser());
      break;
    case MCObjectFileInfo::IsMachO:
      PlatformParser.reset(createDarwinAsmParser());
      IsDarwin = true;
      break;
    case MCObjectFileInfo::IsELF:
      PlatformParser.reset(createELFAsmParser());
      break;
    }
  
    PlatformParser->Initialize(*this);
    initializeDirectiveKindMap();
  
    NumOfMacroInstantiations = 0;
  }
  
  AsmParser::~AsmParser() {
    assert((HadError || ActiveMacros.empty()) &&
           "Unexpected active macro instantiation!");
  }
  
  void AsmParser::printMacroInstantiations() {
    // Print the active macro instantiation stack.
    for (std::vector<MacroInstantiation *>::const_reverse_iterator
             it = ActiveMacros.rbegin(),
             ie = ActiveMacros.rend();
         it != ie; ++it)
      printMessage((*it)->InstantiationLoc, SourceMgr::DK_Note,
                   "while in macro instantiation");
  }
  
  void AsmParser::Note(SMLoc L, const Twine &Msg, ArrayRef<SMRange> Ranges) {
    printMessage(L, SourceMgr::DK_Note, Msg, Ranges);
    printMacroInstantiations();
  }
  
  bool AsmParser::Warning(SMLoc L, const Twine &Msg, ArrayRef<SMRange> Ranges) {
    if(getTargetParser().getTargetOptions().MCNoWarn)
      return false;
    if (getTargetParser().getTargetOptions().MCFatalWarnings)
      return Error(L, Msg, Ranges);
    printMessage(L, SourceMgr::DK_Warning, Msg, Ranges);
    printMacroInstantiations();
    return false;
  }
  
  bool AsmParser::Error(SMLoc L, const Twine &Msg, ArrayRef<SMRange> Ranges) {
    HadError = true;
    printMessage(L, SourceMgr::DK_Error, Msg, Ranges);
    printMacroInstantiations();
    return true;
  }
  
  bool AsmParser::enterIncludeFile(const std::string &Filename) {
    std::string IncludedFile;
    unsigned NewBuf =
        SrcMgr.AddIncludeFile(Filename, Lexer.getLoc(), IncludedFile);
    if (!NewBuf)
      return true;
  
    CurBuffer = NewBuf;
    Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer());
    return false;
  }
  
  /// Process the specified .incbin file by searching for it in the include paths
  /// then just emitting the byte contents of the file to the streamer. This
  /// returns true on failure.
  bool AsmParser::processIncbinFile(const std::string &Filename) {
    std::string IncludedFile;
    unsigned NewBuf =
        SrcMgr.AddIncludeFile(Filename, Lexer.getLoc(), IncludedFile);
    if (!NewBuf)
      return true;
  
    // Pick up the bytes from the file and emit them.
    getStreamer().EmitBytes(SrcMgr.getMemoryBuffer(NewBuf)->getBuffer());
    return false;
  }
  
  void AsmParser::jumpToLoc(SMLoc Loc, unsigned InBuffer) {
    CurBuffer = InBuffer ? InBuffer : SrcMgr.FindBufferContainingLoc(Loc);
    Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer(),
                    Loc.getPointer());
  }
  
  const AsmToken &AsmParser::Lex() {
    const AsmToken *tok = &Lexer.Lex();
  
    if (tok->is(AsmToken::Eof)) {
      // If this is the end of an included file, pop the parent file off the
      // include stack.
      SMLoc ParentIncludeLoc = SrcMgr.getParentIncludeLoc(CurBuffer);
      if (ParentIncludeLoc != SMLoc()) {
        jumpToLoc(ParentIncludeLoc);
        tok = &Lexer.Lex();
      }
    }
  
    if (tok->is(AsmToken::Error))
      Error(Lexer.getErrLoc(), Lexer.getErr());
  
    return *tok;
  }
  
  bool AsmParser::Run(bool NoInitialTextSection, bool NoFinalize) {
    // Create the initial section, if requested.
    if (!NoInitialTextSection)
      Out.InitSections(false);
  
    // Prime the lexer.
    Lex();
  
    HadError = false;
    AsmCond StartingCondState = TheCondState;
  
    // If we are generating dwarf for assembly source files save the initial text
    // section and generate a .file directive.
    if (getContext().getGenDwarfForAssembly()) {
      MCSection *Sec = getStreamer().getCurrentSection().first;
      if (!Sec->getBeginSymbol()) {
        MCSymbol *SectionStartSym = getContext().createTempSymbol();
        getStreamer().EmitLabel(SectionStartSym);
        Sec->setBeginSymbol(SectionStartSym);
      }
      bool InsertResult = getContext().addGenDwarfSection(Sec);
      assert(InsertResult && ".text section should not have debug info yet");
      (void)InsertResult;
      getContext().setGenDwarfFileNumber(getStreamer().EmitDwarfFileDirective(
          0, StringRef(), getContext().getMainFileName()));
    }
  
    // While we have input, parse each statement.
    while (Lexer.isNot(AsmToken::Eof)) {
      ParseStatementInfo Info;
      if (!parseStatement(Info, nullptr))
        continue;
  
      // We had an error, validate that one was emitted and recover by skipping to
      // the next line.
      assert(HadError && "Parse statement returned an error, but none emitted!");
      eatToEndOfStatement();
    }
  
    if (TheCondState.TheCond != StartingCondState.TheCond ||
        TheCondState.Ignore != StartingCondState.Ignore)
      return TokError("unmatched .ifs or .elses");
  
    // Check to see there are no empty DwarfFile slots.
    const auto &LineTables = getContext().getMCDwarfLineTables();
    if (!LineTables.empty()) {
      unsigned Index = 0;
      for (const auto &File : LineTables.begin()->second.getMCDwarfFiles()) {
        if (File.Name.empty() && Index != 0)
          TokError("unassigned file number: " + Twine(Index) +
                   " for .file directives");
        ++Index;
      }
    }
  
    // Check to see that all assembler local symbols were actually defined.
    // Targets that don't do subsections via symbols may not want this, though,
    // so conservatively exclude them. Only do this if we're finalizing, though,
    // as otherwise we won't necessarilly have seen everything yet.
    if (!NoFinalize && MAI.hasSubsectionsViaSymbols()) {
      for (const auto &TableEntry : getContext().getSymbols()) {
        MCSymbol *Sym = TableEntry.getValue();
        // Variable symbols may not be marked as defined, so check those
        // explicitly. If we know it's a variable, we have a definition for
        // the purposes of this check.
        if (Sym->isTemporary() && !Sym->isVariable() && !Sym->isDefined())
          // FIXME: We would really like to refer back to where the symbol was
          // first referenced for a source location. We need to add something
          // to track that. Currently, we just point to the end of the file.
          return Error(getLexer().getLoc(), "assembler local symbol '" +
                                                Sym->getName() + "' not defined");
      }
    }
  
    // Finalize the output stream if there are no errors and if the client wants
    // us to.
    if (!HadError && !NoFinalize)
      Out.Finish();
  
    return HadError || getContext().hadError();
  }
  
  void AsmParser::checkForValidSection() {
    if (!ParsingInlineAsm && !getStreamer().getCurrentSection().first) {
      TokError("expected section directive before assembly directive");
      Out.InitSections(false);
    }
  }
  
  /// \brief Throw away the rest of the line for testing purposes.
  void AsmParser::eatToEndOfStatement() {
    while (Lexer.isNot(AsmToken::EndOfStatement) && Lexer.isNot(AsmToken::Eof))
      Lex();
  
    // Eat EOL.
    if (Lexer.is(AsmToken::EndOfStatement))
      Lex();
  }
  
  StringRef AsmParser::parseStringToEndOfStatement() {
    const char *Start = getTok().getLoc().getPointer();
  
    while (Lexer.isNot(AsmToken::EndOfStatement) && Lexer.isNot(AsmToken::Eof))
      Lex();
  
    const char *End = getTok().getLoc().getPointer();
    return StringRef(Start, End - Start);
  }
  
  StringRef AsmParser::parseStringToComma() {
    const char *Start = getTok().getLoc().getPointer();
  
    while (Lexer.isNot(AsmToken::EndOfStatement) &&
           Lexer.isNot(AsmToken::Comma) && Lexer.isNot(AsmToken::Eof))
      Lex();
  
    const char *End = getTok().getLoc().getPointer();
    return StringRef(Start, End - Start);
  }
  
  /// \brief Parse a paren expression and return it.
  /// NOTE: This assumes the leading '(' has already been consumed.
  ///
  /// parenexpr ::= expr)
  ///
  bool AsmParser::parseParenExpr(const MCExpr *&Res, SMLoc &EndLoc) {
    if (parseExpression(Res))
      return true;
    if (Lexer.isNot(AsmToken::RParen))
      return TokError("expected ')' in parentheses expression");
    EndLoc = Lexer.getTok().getEndLoc();
    Lex();
    return false;
  }
  
  /// \brief Parse a bracket expression and return it.
  /// NOTE: This assumes the leading '[' has already been consumed.
  ///
  /// bracketexpr ::= expr]
  ///
  bool AsmParser::parseBracketExpr(const MCExpr *&Res, SMLoc &EndLoc) {
    if (parseExpression(Res))
      return true;
    if (Lexer.isNot(AsmToken::RBrac))
      return TokError("expected ']' in brackets expression");
    EndLoc = Lexer.getTok().getEndLoc();
    Lex();
    return false;
  }
  
  /// \brief Parse a primary expression and return it.
  ///  primaryexpr ::= (parenexpr
  ///  primaryexpr ::= symbol
  ///  primaryexpr ::= number
  ///  primaryexpr ::= '.'
  ///  primaryexpr ::= ~,+,- primaryexpr
  bool AsmParser::parsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
    SMLoc FirstTokenLoc = getLexer().getLoc();
    AsmToken::TokenKind FirstTokenKind = Lexer.getKind();
    switch (FirstTokenKind) {
    default:
      return TokError("unknown token in expression");
    // If we have an error assume that we've already handled it.
    case AsmToken::Error:
      return true;
    case AsmToken::Exclaim:
      Lex(); // Eat the operator.
      if (parsePrimaryExpr(Res, EndLoc))
        return true;
      Res = MCUnaryExpr::createLNot(Res, getContext());
      return false;
    case AsmToken::Dollar:
    case AsmToken::At:
    case AsmToken::String:
    case AsmToken::Identifier: {
      StringRef Identifier;
      if (parseIdentifier(Identifier)) {
        if (FirstTokenKind == AsmToken::Dollar) {
          if (Lexer.getMAI().getDollarIsPC()) {
            // This is a '$' reference, which references the current PC.  Emit a
            // temporary label to the streamer and refer to it.
            MCSymbol *Sym = Ctx.createTempSymbol();
            Out.EmitLabel(Sym);
            Res = MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None,
                                          getContext());
            EndLoc = FirstTokenLoc;
            return false;
          }
          return Error(FirstTokenLoc, "invalid token in expression");
        }
      }
      // Parse symbol variant
      std::pair<StringRef, StringRef> Split;
      if (!MAI.useParensForSymbolVariant()) {
        if (FirstTokenKind == AsmToken::String) {
          if (Lexer.is(AsmToken::At)) {
            Lexer.Lex(); // eat @
            SMLoc AtLoc = getLexer().getLoc();
            StringRef VName;
            if (parseIdentifier(VName))
              return Error(AtLoc, "expected symbol variant after '@'");
  
            Split = std::make_pair(Identifier, VName);
          }
        } else {
          Split = Identifier.split('@');
        }
      } else if (Lexer.is(AsmToken::LParen)) {
        Lexer.Lex(); // eat (
        StringRef VName;
        parseIdentifier(VName);
        if (Lexer.isNot(AsmToken::RParen)) {
            return Error(Lexer.getTok().getLoc(),
                         "unexpected token in variant, expected ')'");
        }
        Lexer.Lex(); // eat )
        Split = std::make_pair(Identifier, VName);
      }
  
      EndLoc = SMLoc::getFromPointer(Identifier.end());
  
      // This is a symbol reference.
      StringRef SymbolName = Identifier;
      MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
  
      // Lookup the symbol variant if used.
      if (Split.second.size()) {
        Variant = MCSymbolRefExpr::getVariantKindForName(Split.second);
        if (Variant != MCSymbolRefExpr::VK_Invalid) {
          SymbolName = Split.first;
        } else if (MAI.doesAllowAtInName() && !MAI.useParensForSymbolVariant()) {
          Variant = MCSymbolRefExpr::VK_None;
        } else {
          return Error(SMLoc::getFromPointer(Split.second.begin()),
                       "invalid variant '" + Split.second + "'");
        }
      }
  
      MCSymbol *Sym = getContext().getOrCreateSymbol(SymbolName);
  
      // If this is an absolute variable reference, substitute it now to preserve
      // semantics in the face of reassignment.
      if (Sym->isVariable() &&
          isa<MCConstantExpr>(Sym->getVariableValue(/*SetUsed*/ false))) {
        if (Variant)
          return Error(EndLoc, "unexpected modifier on variable reference");
  
        Res = Sym->getVariableValue(/*SetUsed*/ false);
        return false;
      }
  
      // Otherwise create a symbol ref.
      Res = MCSymbolRefExpr::create(Sym, Variant, getContext());
      return false;
    }
    case AsmToken::BigNum:
      return TokError("literal value out of range for directive");
    case AsmToken::Integer: {
      SMLoc Loc = getTok().getLoc();
      int64_t IntVal = getTok().getIntVal();
      Res = MCConstantExpr::create(IntVal, getContext());
      EndLoc = Lexer.getTok().getEndLoc();
      Lex(); // Eat token.
      // Look for 'b' or 'f' following an Integer as a directional label
      if (Lexer.getKind() == AsmToken::Identifier) {
        StringRef IDVal = getTok().getString();
        // Lookup the symbol variant if used.
        std::pair<StringRef, StringRef> Split = IDVal.split('@');
        MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
        if (Split.first.size() != IDVal.size()) {
          Variant = MCSymbolRefExpr::getVariantKindForName(Split.second);
          if (Variant == MCSymbolRefExpr::VK_Invalid)
            return TokError("invalid variant '" + Split.second + "'");
          IDVal = Split.first;
        }
        if (IDVal == "f" || IDVal == "b") {
          MCSymbol *Sym =
              Ctx.getDirectionalLocalSymbol(IntVal, IDVal == "b");
          Res = MCSymbolRefExpr::create(Sym, Variant, getContext());
          if (IDVal == "b" && Sym->isUndefined())
            return Error(Loc, "invalid reference to undefined symbol");
          EndLoc = Lexer.getTok().getEndLoc();
          Lex(); // Eat identifier.
        }
      }
      return false;
    }
    case AsmToken::Real: {
      APFloat RealVal(APFloat::IEEEdouble, getTok().getString());
      uint64_t IntVal = RealVal.bitcastToAPInt().getZExtValue();
      Res = MCConstantExpr::create(IntVal, getContext());
      EndLoc = Lexer.getTok().getEndLoc();
      Lex(); // Eat token.
      return false;
    }
    case AsmToken::Dot: {
      // This is a '.' reference, which references the current PC.  Emit a
      // temporary label to the streamer and refer to it.
      MCSymbol *Sym = Ctx.createTempSymbol();
      Out.EmitLabel(Sym);
      Res = MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None, getContext());
      EndLoc = Lexer.getTok().getEndLoc();
      Lex(); // Eat identifier.
      return false;
    }
    case AsmToken::LParen:
      Lex(); // Eat the '('.
      return parseParenExpr(Res, EndLoc);
    case AsmToken::LBrac:
      if (!PlatformParser->HasBracketExpressions())
        return TokError("brackets expression not supported on this target");
      Lex(); // Eat the '['.
      return parseBracketExpr(Res, EndLoc);
    case AsmToken::Minus:
      Lex(); // Eat the operator.
      if (parsePrimaryExpr(Res, EndLoc))
        return true;
      Res = MCUnaryExpr::createMinus(Res, getContext());
      return false;
    case AsmToken::Plus:
      Lex(); // Eat the operator.
      if (parsePrimaryExpr(Res, EndLoc))
        return true;
      Res = MCUnaryExpr::createPlus(Res, getContext());
      return false;
    case AsmToken::Tilde:
      Lex(); // Eat the operator.
      if (parsePrimaryExpr(Res, EndLoc))
        return true;
      Res = MCUnaryExpr::createNot(Res, getContext());
      return false;
    }
  }
  
  bool AsmParser::parseExpression(const MCExpr *&Res) {
    SMLoc EndLoc;
    return parseExpression(Res, EndLoc);
  }
  
  const MCExpr *
  AsmParser::applyModifierToExpr(const MCExpr *E,
                                 MCSymbolRefExpr::VariantKind Variant) {
    // Ask the target implementation about this expression first.
    const MCExpr *NewE = getTargetParser().applyModifierToExpr(E, Variant, Ctx);
    if (NewE)
      return NewE;
    // Recurse over the given expression, rebuilding it to apply the given variant
    // if there is exactly one symbol.
    switch (E->getKind()) {
    case MCExpr::Target:
    case MCExpr::Constant:
      return nullptr;
  
    case MCExpr::SymbolRef: {
      const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(E);
  
      if (SRE->getKind() != MCSymbolRefExpr::VK_None) {
        TokError("invalid variant on expression '" + getTok().getIdentifier() +
                 "' (already modified)");
        return E;
      }
  
      return MCSymbolRefExpr::create(&SRE->getSymbol(), Variant, getContext());
    }
  
    case MCExpr::Unary: {
      const MCUnaryExpr *UE = cast<MCUnaryExpr>(E);
      const MCExpr *Sub = applyModifierToExpr(UE->getSubExpr(), Variant);
      if (!Sub)
        return nullptr;
      return MCUnaryExpr::create(UE->getOpcode(), Sub, getContext());
    }
  
    case MCExpr::Binary: {
      const MCBinaryExpr *BE = cast<MCBinaryExpr>(E);
      const MCExpr *LHS = applyModifierToExpr(BE->getLHS(), Variant);
      const MCExpr *RHS = applyModifierToExpr(BE->getRHS(), Variant);
  
      if (!LHS && !RHS)
        return nullptr;
  
      if (!LHS)
        LHS = BE->getLHS();
      if (!RHS)
        RHS = BE->getRHS();
  
      return MCBinaryExpr::create(BE->getOpcode(), LHS, RHS, getContext());
    }
    }
  
    llvm_unreachable("Invalid expression kind!");
  }
  
  /// \brief Parse an expression and return it.
  ///
  ///  expr ::= expr &&,|| expr               -> lowest.
  ///  expr ::= expr |,^,&,! expr
  ///  expr ::= expr ==,!=,<>,<,<=,>,>= expr
  ///  expr ::= expr <<,>> expr
  ///  expr ::= expr +,- expr
  ///  expr ::= expr *,/,% expr               -> highest.
  ///  expr ::= primaryexpr
  ///
  bool AsmParser::parseExpression(const MCExpr *&Res, SMLoc &EndLoc) {
    // Parse the expression.
    Res = nullptr;
    if (parsePrimaryExpr(Res, EndLoc) || parseBinOpRHS(1, Res, EndLoc))
      return true;
  
    // As a special case, we support 'a op b @ modifier' by rewriting the
    // expression to include the modifier. This is inefficient, but in general we
    // expect users to use 'a@modifier op b'.
    if (Lexer.getKind() == AsmToken::At) {
      Lex();
  
      if (Lexer.isNot(AsmToken::Identifier))
        return TokError("unexpected symbol modifier following '@'");
  
      MCSymbolRefExpr::VariantKind Variant =
          MCSymbolRefExpr::getVariantKindForName(getTok().getIdentifier());
      if (Variant == MCSymbolRefExpr::VK_Invalid)
        return TokError("invalid variant '" + getTok().getIdentifier() + "'");
  
      const MCExpr *ModifiedRes = applyModifierToExpr(Res, Variant);
      if (!ModifiedRes) {
        return TokError("invalid modifier '" + getTok().getIdentifier() +
                        "' (no symbols present)");
      }
  
      Res = ModifiedRes;
      Lex();
    }
  
    // Try to constant fold it up front, if possible.
    int64_t Value;
    if (Res->evaluateAsAbsolute(Value))
      Res = MCConstantExpr::create(Value, getContext());
  
    return false;
  }
  
  bool AsmParser::parseParenExpression(const MCExpr *&Res, SMLoc &EndLoc) {
    Res = nullptr;
    return parseParenExpr(Res, EndLoc) || parseBinOpRHS(1, Res, EndLoc);
  }
  
  bool AsmParser::parseParenExprOfDepth(unsigned ParenDepth, const MCExpr *&Res,
                                        SMLoc &EndLoc) {
    if (parseParenExpr(Res, EndLoc))
      return true;
  
    for (; ParenDepth > 0; --ParenDepth) {
      if (parseBinOpRHS(1, Res, EndLoc))
        return true;
  
      // We don't Lex() the last RParen.
      // This is the same behavior as parseParenExpression().
      if (ParenDepth - 1 > 0) {
        if (Lexer.isNot(AsmToken::RParen))
          return TokError("expected ')' in parentheses expression");
        EndLoc = Lexer.getTok().getEndLoc();
        Lex();
      }
    }
    return false;
  }
  
  bool AsmParser::parseAbsoluteExpression(int64_t &Res) {
    const MCExpr *Expr;
  
    SMLoc StartLoc = Lexer.getLoc();
    if (parseExpression(Expr))
      return true;
  
    if (!Expr->evaluateAsAbsolute(Res))
      return Error(StartLoc, "expected absolute expression");
  
    return false;
  }
  
  static unsigned getDarwinBinOpPrecedence(AsmToken::TokenKind K,
                                           MCBinaryExpr::Opcode &Kind,
                                           bool ShouldUseLogicalShr) {
    switch (K) {
    default:
      return 0; // not a binop.
  
    // Lowest Precedence: &&, ||
    case AsmToken::AmpAmp:
      Kind = MCBinaryExpr::LAnd;
      return 1;
    case AsmToken::PipePipe:
      Kind = MCBinaryExpr::LOr;
      return 1;
  
    // Low Precedence: |, &, ^
    //
    // FIXME: gas seems to support '!' as an infix operator?
    case AsmToken::Pipe:
      Kind = MCBinaryExpr::Or;
      return 2;
    case AsmToken::Caret:
      Kind = MCBinaryExpr::Xor;
      return 2;
    case AsmToken::Amp:
      Kind = MCBinaryExpr::And;
      return 2;
  
    // Low Intermediate Precedence: ==, !=, <>, <, <=, >, >=
    case AsmToken::EqualEqual:
      Kind = MCBinaryExpr::EQ;
      return 3;
    case AsmToken::ExclaimEqual:
    case AsmToken::LessGreater:
      Kind = MCBinaryExpr::NE;
      return 3;
    case AsmToken::Less:
      Kind = MCBinaryExpr::LT;
      return 3;
    case AsmToken::LessEqual:
      Kind = MCBinaryExpr::LTE;
      return 3;
    case AsmToken::Greater:
      Kind = MCBinaryExpr::GT;
      return 3;
    case AsmToken::GreaterEqual:
      Kind = MCBinaryExpr::GTE;
      return 3;
  
    // Intermediate Precedence: <<, >>
    case AsmToken::LessLess:
      Kind = MCBinaryExpr::Shl;
      return 4;
    case AsmToken::GreaterGreater:
      Kind = ShouldUseLogicalShr ? MCBinaryExpr::LShr : MCBinaryExpr::AShr;
      return 4;
  
    // High Intermediate Precedence: +, -
    case AsmToken::Plus:
      Kind = MCBinaryExpr::Add;
      return 5;
    case AsmToken::Minus:
      Kind = MCBinaryExpr::Sub;
      return 5;
  
    // Highest Precedence: *, /, %
    case AsmToken::Star:
      Kind = MCBinaryExpr::Mul;
      return 6;
    case AsmToken::Slash:
      Kind = MCBinaryExpr::Div;
      return 6;
    case AsmToken::Percent:
      Kind = MCBinaryExpr::Mod;
      return 6;
    }
  }
  
  static unsigned getGNUBinOpPrecedence(AsmToken::TokenKind K,
                                        MCBinaryExpr::Opcode &Kind,
                                        bool ShouldUseLogicalShr) {
    switch (K) {
    default:
      return 0; // not a binop.
  
    // Lowest Precedence: &&, ||
    case AsmToken::AmpAmp:
      Kind = MCBinaryExpr::LAnd;
      return 2;
    case AsmToken::PipePipe:
      Kind = MCBinaryExpr::LOr;
      return 1;
  
    // Low Precedence: ==, !=, <>, <, <=, >, >=
    case AsmToken::EqualEqual:
      Kind = MCBinaryExpr::EQ;
      return 3;
    case AsmToken::ExclaimEqual:
    case AsmToken::LessGreater:
      Kind = MCBinaryExpr::NE;
      return 3;
    case AsmToken::Less:
      Kind = MCBinaryExpr::LT;
      return 3;
    case AsmToken::LessEqual:
      Kind = MCBinaryExpr::LTE;
      return 3;
    case AsmToken::Greater:
      Kind = MCBinaryExpr::GT;
      return 3;
    case AsmToken::GreaterEqual:
      Kind = MCBinaryExpr::GTE;
      return 3;
  
    // Low Intermediate Precedence: +, -
    case AsmToken::Plus:
      Kind = MCBinaryExpr::Add;
      return 4;
    case AsmToken::Minus:
      Kind = MCBinaryExpr::Sub;
      return 4;
  
    // High Intermediate Precedence: |, &, ^
    //
    // FIXME: gas seems to support '!' as an infix operator?
    case AsmToken::Pipe:
      Kind = MCBinaryExpr::Or;
      return 5;
    case AsmToken::Caret:
      Kind = MCBinaryExpr::Xor;
      return 5;
    case AsmToken::Amp:
      Kind = MCBinaryExpr::And;
      return 5;
  
    // Highest Precedence: *, /, %, <<, >>
    case AsmToken::Star:
      Kind = MCBinaryExpr::Mul;
      return 6;
    case AsmToken::Slash:
      Kind = MCBinaryExpr::Div;
      return 6;
    case AsmToken::Percent:
      Kind = MCBinaryExpr::Mod;
      return 6;
    case AsmToken::LessLess:
      Kind = MCBinaryExpr::Shl;
      return 6;
    case AsmToken::GreaterGreater:
      Kind = ShouldUseLogicalShr ? MCBinaryExpr::LShr : MCBinaryExpr::AShr;
      return 6;
    }
  }
  
  unsigned AsmParser::getBinOpPrecedence(AsmToken::TokenKind K,
                                         MCBinaryExpr::Opcode &Kind) {
    bool ShouldUseLogicalShr = MAI.shouldUseLogicalShr();
    return IsDarwin ? getDarwinBinOpPrecedence(K, Kind, ShouldUseLogicalShr)
                    : getGNUBinOpPrecedence(K, Kind, ShouldUseLogicalShr);
  }
  
  /// \brief Parse all binary operators with precedence >= 'Precedence'.
  /// Res contains the LHS of the expression on input.
  bool AsmParser::parseBinOpRHS(unsigned Precedence, const MCExpr *&Res,
                                SMLoc &EndLoc) {
    while (1) {
      MCBinaryExpr::Opcode Kind = MCBinaryExpr::Add;
      unsigned TokPrec = getBinOpPrecedence(Lexer.getKind(), Kind);
  
      // If the next token is lower precedence than we are allowed to eat, return
      // successfully with what we ate already.
      if (TokPrec < Precedence)
        return false;
  
      Lex();
  
      // Eat the next primary expression.
      const MCExpr *RHS;
      if (parsePrimaryExpr(RHS, EndLoc))
        return true;
  
      // If BinOp binds less tightly with RHS than the operator after RHS, let
      // the pending operator take RHS as its LHS.
      MCBinaryExpr::Opcode Dummy;
      unsigned NextTokPrec = getBinOpPrecedence(Lexer.getKind(), Dummy);
      if (TokPrec < NextTokPrec && parseBinOpRHS(TokPrec + 1, RHS, EndLoc))
        return true;
  
      // Merge LHS and RHS according to operator.
      Res = MCBinaryExpr::create(Kind, Res, RHS, getContext());
    }
  }
  
  /// ParseStatement:
  ///   ::= EndOfStatement
  ///   ::= Label* Directive ...Operands... EndOfStatement
  ///   ::= Label* Identifier OperandList* EndOfStatement
  bool AsmParser::parseStatement(ParseStatementInfo &Info,
                                 MCAsmParserSemaCallback *SI) {
    if (Lexer.is(AsmToken::EndOfStatement)) {
      Out.AddBlankLine();
      Lex();
      return false;
    }
  
    // Statements always start with an identifier or are a full line comment.
    AsmToken ID = getTok();
    SMLoc IDLoc = ID.getLoc();
    StringRef IDVal;
    int64_t LocalLabelVal = -1;
    // A full line comment is a '#' as the first token.
    if (Lexer.is(AsmToken::Hash))
      return parseCppHashLineFilenameComment(IDLoc);
  
    // Allow an integer followed by a ':' as a directional local label.
    if (Lexer.is(AsmToken::Integer)) {
      LocalLabelVal = getTok().getIntVal();
      if (LocalLabelVal < 0) {
        if (!TheCondState.Ignore)
          return TokError("unexpected token at start of statement");
        IDVal = "";
      } else {
        IDVal = getTok().getString();
        Lex(); // Consume the integer token to be used as an identifier token.
        if (Lexer.getKind() != AsmToken::Colon) {
          if (!TheCondState.Ignore)
            return TokError("unexpected token at start of statement");
        }
      }
    } else if (Lexer.is(AsmToken::Dot)) {
      // Treat '.' as a valid identifier in this context.
      Lex();
      IDVal = ".";
    } else if (Lexer.is(AsmToken::LCurly)) {
      // Treat '{' as a valid identifier in this context.
      Lex();
      IDVal = "{";
  
    } else if (Lexer.is(AsmToken::RCurly)) {
      // Treat '}' as a valid identifier in this context.
      Lex();
      IDVal = "}";
    } else if (parseIdentifier(IDVal)) {
      if (!TheCondState.Ignore)
        return TokError("unexpected token at start of statement");
      IDVal = "";
    }
  
    // Handle conditional assembly here before checking for skipping.  We
    // have to do this so that .endif isn't skipped in a ".if 0" block for
    // example.
    StringMap<DirectiveKind>::const_iterator DirKindIt =
        DirectiveKindMap.find(IDVal);
    DirectiveKind DirKind = (DirKindIt == DirectiveKindMap.end())
                                ? DK_NO_DIRECTIVE
                                : DirKindIt->getValue();
    switch (DirKind) {
    default:
      break;
    case DK_IF:
    case DK_IFEQ:
    case DK_IFGE:
    case DK_IFGT:
    case DK_IFLE:
    case DK_IFLT:
    case DK_IFNE:
      return parseDirectiveIf(IDLoc, DirKind);
    case DK_IFB:
      return parseDirectiveIfb(IDLoc, true);
    case DK_IFNB:
      return parseDirectiveIfb(IDLoc, false);
    case DK_IFC:
      return parseDirectiveIfc(IDLoc, true);
    case DK_IFEQS:
      return parseDirectiveIfeqs(IDLoc, true);
    case DK_IFNC:
      return parseDirectiveIfc(IDLoc, false);
    case DK_IFNES:
      return parseDirectiveIfeqs(IDLoc, false);
    case DK_IFDEF:
      return parseDirectiveIfdef(IDLoc, true);
    case DK_IFNDEF:
    case DK_IFNOTDEF:
      return parseDirectiveIfdef(IDLoc, false);
    case DK_ELSEIF:
      return parseDirectiveElseIf(IDLoc);
    case DK_ELSE:
      return parseDirectiveElse(IDLoc);
    case DK_ENDIF:
      return parseDirectiveEndIf(IDLoc);
    }
  
    // Ignore the statement if in the middle of inactive conditional
    // (e.g. ".if 0").
    if (TheCondState.Ignore) {
      eatToEndOfStatement();
      return false;
    }
  
    // FIXME: Recurse on local labels?
  
    // See what kind of statement we have.
    switch (Lexer.getKind()) {
    case AsmToken::Colon: {
      if (!getTargetParser().isLabel(ID))
        break;
      checkForValidSection();
  
      // identifier ':'   -> Label.
      Lex();
  
      // Diagnose attempt to use '.' as a label.
      if (IDVal == ".")
        return Error(IDLoc, "invalid use of pseudo-symbol '.' as a label");
  
      // Diagnose attempt to use a variable as a label.
      //
      // FIXME: Diagnostics. Note the location of the definition as a label.
      // FIXME: This doesn't diagnose assignment to a symbol which has been
      // implicitly marked as external.
      MCSymbol *Sym;
      if (LocalLabelVal == -1) {
        if (ParsingInlineAsm && SI) {
          StringRef RewrittenLabel =
              SI->LookupInlineAsmLabel(IDVal, getSourceManager(), IDLoc, true);
          assert(RewrittenLabel.size() &&
                 "We should have an internal name here.");
          Info.AsmRewrites->emplace_back(AOK_Label, IDLoc, IDVal.size(),
                                         RewrittenLabel);
          IDVal = RewrittenLabel;
        }
        Sym = getContext().getOrCreateSymbol(IDVal);
      } else
        Sym = Ctx.createDirectionalLocalSymbol(LocalLabelVal);
  
      Sym->redefineIfPossible();
  
      if (!Sym->isUndefined() || Sym->isVariable())
        return Error(IDLoc, "invalid symbol redefinition");
  
      // Emit the label.
      if (!ParsingInlineAsm)
        Out.EmitLabel(Sym);
  
      // If we are generating dwarf for assembly source files then gather the
      // info to make a dwarf label entry for this label if needed.
      if (getContext().getGenDwarfForAssembly())
        MCGenDwarfLabelEntry::Make(Sym, &getStreamer(), getSourceManager(),
                                   IDLoc);
  
      getTargetParser().onLabelParsed(Sym);
  
      // Consume any end of statement token, if present, to avoid spurious
      // AddBlankLine calls().
      if (Lexer.is(AsmToken::EndOfStatement)) {
        Lex();
        if (Lexer.is(AsmToken::Eof))
          return false;
      }
  
      return false;
    }
  
    case AsmToken::Equal:
      if (!getTargetParser().equalIsAsmAssignment())
        break;
      // identifier '=' ... -> assignment statement
      Lex();
  
      return parseAssignment(IDVal, true);
  
    default: // Normal instruction or directive.
      break;
    }
  
    // If macros are enabled, check to see if this is a macro instantiation.
    if (areMacrosEnabled())
      if (const MCAsmMacro *M = lookupMacro(IDVal)) {
        return handleMacroEntry(M, IDLoc);
      }
  
    // Otherwise, we have a normal instruction or directive.
  
    // Directives start with "."
    if (IDVal[0] == '.' && IDVal != ".") {
      // There are several entities interested in parsing directives:
      //
      // 1. The target-specific assembly parser. Some directives are target
      //    specific or may potentially behave differently on certain targets.
      // 2. Asm parser extensions. For example, platform-specific parsers
      //    (like the ELF parser) register themselves as extensions.
      // 3. The generic directive parser implemented by this class. These are
      //    all the directives that behave in a target and platform independent
      //    manner, or at least have a default behavior that's shared between
      //    all targets and platforms.
  
      // First query the target-specific parser. It will return 'true' if it
      // isn't interested in this directive.
      if (!getTargetParser().ParseDirective(ID))
        return false;
  
      // Next, check the extension directive map to see if any extension has
      // registered itself to parse this directive.
      std::pair<MCAsmParserExtension *, DirectiveHandler> Handler =
          ExtensionDirectiveMap.lookup(IDVal);
      if (Handler.first)
        return (*Handler.second)(Handler.first, IDVal, IDLoc);
  
      // Finally, if no one else is interested in this directive, it must be
      // generic and familiar to this class.
      switch (DirKind) {
      default:
        break;
      case DK_SET:
      case DK_EQU:
        return parseDirectiveSet(IDVal, true);
      case DK_EQUIV:
        return parseDirectiveSet(IDVal, false);
      case DK_ASCII:
        return parseDirectiveAscii(IDVal, false);
      case DK_ASCIZ:
      case DK_STRING:
        return parseDirectiveAscii(IDVal, true);
      case DK_BYTE:
        return parseDirectiveValue(1);
      case DK_SHORT:
      case DK_VALUE:
      case DK_2BYTE:
        return parseDirectiveValue(2);
      case DK_LONG:
      case DK_INT:
      case DK_4BYTE:
        return parseDirectiveValue(4);
      case DK_QUAD:
      case DK_8BYTE:
        return parseDirectiveValue(8);
      case DK_OCTA:
        return parseDirectiveOctaValue();
      case DK_SINGLE:
      case DK_FLOAT:
        return parseDirectiveRealValue(APFloat::IEEEsingle);
      case DK_DOUBLE:
        return parseDirectiveRealValue(APFloat::IEEEdouble);
      case DK_ALIGN: {
        bool IsPow2 = !getContext().getAsmInfo()->getAlignmentIsInBytes();
        return parseDirectiveAlign(IsPow2, /*ExprSize=*/1);
      }
      case DK_ALIGN32: {
        bool IsPow2 = !getContext().getAsmInfo()->getAlignmentIsInBytes();
        return parseDirectiveAlign(IsPow2, /*ExprSize=*/4);
      }
      case DK_BALIGN:
        return parseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/1);
      case DK_BALIGNW:
        return parseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/2);
      case DK_BALIGNL:
        return parseDirectiveAlign(/*IsPow2=*/false, /*ExprSize=*/4);
      case DK_P2ALIGN:
        return parseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/1);
      case DK_P2ALIGNW:
        return parseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/2);
      case DK_P2ALIGNL:
        return parseDirectiveAlign(/*IsPow2=*/true, /*ExprSize=*/4);
      case DK_ORG:
        return parseDirectiveOrg();
      case DK_FILL:
        return parseDirectiveFill();
      case DK_ZERO:
        return parseDirectiveZero();
      case DK_EXTERN:
        eatToEndOfStatement(); // .extern is the default, ignore it.
        return false;
      case DK_GLOBL:
      case DK_GLOBAL:
        return parseDirectiveSymbolAttribute(MCSA_Global);
      case DK_LAZY_REFERENCE:
        return parseDirectiveSymbolAttribute(MCSA_LazyReference);
      case DK_NO_DEAD_STRIP:
        return parseDirectiveSymbolAttribute(MCSA_NoDeadStrip);
      case DK_SYMBOL_RESOLVER:
        return parseDirectiveSymbolAttribute(MCSA_SymbolResolver);
      case DK_PRIVATE_EXTERN:
        return parseDirectiveSymbolAttribute(MCSA_PrivateExtern);
      case DK_REFERENCE:
        return parseDirectiveSymbolAttribute(MCSA_Reference);
      case DK_WEAK_DEFINITION:
        return parseDirectiveSymbolAttribute(MCSA_WeakDefinition);
      case DK_WEAK_REFERENCE:
        return parseDirectiveSymbolAttribute(MCSA_WeakReference);
      case DK_WEAK_DEF_CAN_BE_HIDDEN:
        return parseDirectiveSymbolAttribute(MCSA_WeakDefAutoPrivate);
      case DK_COMM:
      case DK_COMMON:
        return parseDirectiveComm(/*IsLocal=*/false);
      case DK_LCOMM:
        return parseDirectiveComm(/*IsLocal=*/true);
      case DK_ABORT:
        return parseDirectiveAbort();
      case DK_INCLUDE:
        return parseDirectiveInclude();
      case DK_INCBIN:
        return parseDirectiveIncbin();
      case DK_CODE16:
      case DK_CODE16GCC:
        return TokError(Twine(IDVal) + " not supported yet");
      case DK_REPT:
        return parseDirectiveRept(IDLoc, IDVal);
      case DK_IRP:
        return parseDirectiveIrp(IDLoc);
      case DK_IRPC:
        return parseDirectiveIrpc(IDLoc);
      case DK_ENDR:
        return parseDirectiveEndr(IDLoc);
      case DK_BUNDLE_ALIGN_MODE:
        return parseDirectiveBundleAlignMode();
      case DK_BUNDLE_LOCK:
        return parseDirectiveBundleLock();
      case DK_BUNDLE_UNLOCK:
        return parseDirectiveBundleUnlock();
      case DK_SLEB128:
        return parseDirectiveLEB128(true);
      case DK_ULEB128:
        return parseDirectiveLEB128(false);
      case DK_SPACE:
      case DK_SKIP:
        return parseDirectiveSpace(IDVal);
      case DK_FILE:
        return parseDirectiveFile(IDLoc);
      case DK_LINE:
        return parseDirectiveLine();
      case DK_LOC:
        return parseDirectiveLoc();
      case DK_STABS:
        return parseDirectiveStabs();
      case DK_CV_FILE:
        return parseDirectiveCVFile();
      case DK_CV_LOC:
        return parseDirectiveCVLoc();
      case DK_CV_LINETABLE:
        return parseDirectiveCVLinetable();
      case DK_CV_INLINE_LINETABLE:
        return parseDirectiveCVInlineLinetable();
      case DK_CV_STRINGTABLE:
        return parseDirectiveCVStringTable();
      case DK_CV_FILECHECKSUMS:
        return parseDirectiveCVFileChecksums();
      case DK_CFI_SECTIONS:
        return parseDirectiveCFISections();
      case DK_CFI_STARTPROC:
        return parseDirectiveCFIStartProc();
      case DK_CFI_ENDPROC:
        return parseDirectiveCFIEndProc();
      case DK_CFI_DEF_CFA:
        return parseDirectiveCFIDefCfa(IDLoc);
      case DK_CFI_DEF_CFA_OFFSET:
        return parseDirectiveCFIDefCfaOffset();
      case DK_CFI_ADJUST_CFA_OFFSET:
        return parseDirectiveCFIAdjustCfaOffset();
      case DK_CFI_DEF_CFA_REGISTER:
        return parseDirectiveCFIDefCfaRegister(IDLoc);
      case DK_CFI_OFFSET:
        return parseDirectiveCFIOffset(IDLoc);
      case DK_CFI_REL_OFFSET:
        return parseDirectiveCFIRelOffset(IDLoc);
      case DK_CFI_PERSONALITY:
        return parseDirectiveCFIPersonalityOrLsda(true);
      case DK_CFI_LSDA:
        return parseDirectiveCFIPersonalityOrLsda(false);
      case DK_CFI_REMEMBER_STATE:
        return parseDirectiveCFIRememberState();
      case DK_CFI_RESTORE_STATE:
        return parseDirectiveCFIRestoreState();
      case DK_CFI_SAME_VALUE:
        return parseDirectiveCFISameValue(IDLoc);
      case DK_CFI_RESTORE:
        return parseDirectiveCFIRestore(IDLoc);
      case DK_CFI_ESCAPE:
        return parseDirectiveCFIEscape();
      case DK_CFI_SIGNAL_FRAME:
        return parseDirectiveCFISignalFrame();
      case DK_CFI_UNDEFINED:
        return parseDirectiveCFIUndefined(IDLoc);
      case DK_CFI_REGISTER:
        return parseDirectiveCFIRegister(IDLoc);
      case DK_CFI_WINDOW_SAVE:
        return parseDirectiveCFIWindowSave();
      case DK_MACROS_ON:
      case DK_MACROS_OFF:
        return parseDirectiveMacrosOnOff(IDVal);
      case DK_MACRO:
        return parseDirectiveMacro(IDLoc);
      case DK_EXITM:
        return parseDirectiveExitMacro(IDVal);
      case DK_ENDM:
      case DK_ENDMACRO:
        return parseDirectiveEndMacro(IDVal);
      case DK_PURGEM:
        return parseDirectivePurgeMacro(IDLoc);
      case DK_END:
        return parseDirectiveEnd(IDLoc);
      case DK_ERR:
        return parseDirectiveError(IDLoc, false);
      case DK_ERROR:
        return parseDirectiveError(IDLoc, true);
      case DK_WARNING:
        return parseDirectiveWarning(IDLoc);
      case DK_RELOC:
        return parseDirectiveReloc(IDLoc);
      }
  
      return Error(IDLoc, "unknown directive");
    }
  
    // __asm _emit or __asm __emit
    if (ParsingInlineAsm && (IDVal == "_emit" || IDVal == "__emit" ||
                             IDVal == "_EMIT" || IDVal == "__EMIT"))
      return parseDirectiveMSEmit(IDLoc, Info, IDVal.size());
  
    // __asm align
    if (ParsingInlineAsm && (IDVal == "align" || IDVal == "ALIGN"))
      return parseDirectiveMSAlign(IDLoc, Info);
  
    if (ParsingInlineAsm && (IDVal == "even"))
      Info.AsmRewrites->emplace_back(AOK_EVEN, IDLoc, 4);
    checkForValidSection();
  
    // Canonicalize the opcode to lower case.
    std::string OpcodeStr = IDVal.lower();
    ParseInstructionInfo IInfo(Info.AsmRewrites);
    bool HadError = getTargetParser().ParseInstruction(IInfo, OpcodeStr, ID,
                                                       Info.ParsedOperands);
    Info.ParseError = HadError;
  
    // Dump the parsed representation, if requested.
    if (getShowParsedOperands()) {
      SmallString<256> Str;
      raw_svector_ostream OS(Str);
      OS << "parsed instruction: [";
      for (unsigned i = 0; i != Info.ParsedOperands.size(); ++i) {
        if (i != 0)
          OS << ", ";
        Info.ParsedOperands[i]->print(OS);
      }
      OS << "]";
  
      printMessage(IDLoc, SourceMgr::DK_Note, OS.str());
    }
  
    // If we are generating dwarf for the current section then generate a .loc
    // directive for the instruction.
    if (!HadError && getContext().getGenDwarfForAssembly() &&
        getContext().getGenDwarfSectionSyms().count(
            getStreamer().getCurrentSection().first)) {
      unsigned Line;
      if (ActiveMacros.empty())
        Line = SrcMgr.FindLineNumber(IDLoc, CurBuffer);
      else
        Line = SrcMgr.FindLineNumber(ActiveMacros.front()->InstantiationLoc,
                                     ActiveMacros.front()->ExitBuffer);
  
      // If we previously parsed a cpp hash file line comment then make sure the
      // current Dwarf File is for the CppHashFilename if not then emit the
      // Dwarf File table for it and adjust the line number for the .loc.
      if (CppHashFilename.size()) {
        unsigned FileNumber = getStreamer().EmitDwarfFileDirective(
            0, StringRef(), CppHashFilename);
        getContext().setGenDwarfFileNumber(FileNumber);
  
        // Since SrcMgr.FindLineNumber() is slow and messes up the SourceMgr's
        // cache with the different Loc from the call above we save the last
        // info we queried here with SrcMgr.FindLineNumber().
        unsigned CppHashLocLineNo;
        if (LastQueryIDLoc == CppHashLoc && LastQueryBuffer == CppHashBuf)
          CppHashLocLineNo = LastQueryLine;
        else {
          CppHashLocLineNo = SrcMgr.FindLineNumber(CppHashLoc, CppHashBuf);
          LastQueryLine = CppHashLocLineNo;
          LastQueryIDLoc = CppHashLoc;
          LastQueryBuffer = CppHashBuf;
        }
        Line = CppHashLineNumber - 1 + (Line - CppHashLocLineNo);
      }
  
      getStreamer().EmitDwarfLocDirective(
          getContext().getGenDwarfFileNumber(), Line, 0,
          DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0, 0, 0,
          StringRef());
    }
  
    // If parsing succeeded, match the instruction.
    if (!HadError) {
      uint64_t ErrorInfo;
      getTargetParser().MatchAndEmitInstruction(IDLoc, Info.Opcode,
                                                Info.ParsedOperands, Out,
                                                ErrorInfo, ParsingInlineAsm);
    }
  
    // Don't skip the rest of the line, the instruction parser is responsible for
    // that.
    return false;
  }
  
  /// eatToEndOfLine uses the Lexer to eat the characters to the end of the line
  /// since they may not be able to be tokenized to get to the end of line token.
  void AsmParser::eatToEndOfLine() {
    if (!Lexer.is(AsmToken::EndOfStatement))
      Lexer.LexUntilEndOfLine();
    // Eat EOL.
    Lex();
  }
  
  /// parseCppHashLineFilenameComment as this:
  ///   ::= # number "filename"
  /// or just as a full line comment if it doesn't have a number and a string.
  bool AsmParser::parseCppHashLineFilenameComment(SMLoc L) {
    Lex(); // Eat the hash token.
  
    if (getLexer().isNot(AsmToken::Integer)) {
      // Consume the line since in cases it is not a well-formed line directive,
      // as if were simply a full line comment.
      eatToEndOfLine();
      return false;
    }
  
    int64_t LineNumber = getTok().getIntVal();
    Lex();
  
    if (getLexer().isNot(AsmToken::String)) {
      eatToEndOfLine();
      return false;
    }
  
    StringRef Filename = getTok().getString();
    // Get rid of the enclosing quotes.
    Filename = Filename.substr(1, Filename.size() - 2);
  
    // Save the SMLoc, Filename and LineNumber for later use by diagnostics.
    CppHashLoc = L;
    CppHashFilename = Filename;
    CppHashLineNumber = LineNumber;
    CppHashBuf = CurBuffer;
  
    // Ignore any trailing characters, they're just comment.
    eatToEndOfLine();
    return false;
  }
  
  /// \brief will use the last parsed cpp hash line filename comment
  /// for the Filename and LineNo if any in the diagnostic.
  void AsmParser::DiagHandler(const SMDiagnostic &Diag, void *Context) {
    const AsmParser *Parser = static_cast<const AsmParser *>(Context);
    raw_ostream &OS = errs();
  
    const SourceMgr &DiagSrcMgr = *Diag.getSourceMgr();
    SMLoc DiagLoc = Diag.getLoc();
    unsigned DiagBuf = DiagSrcMgr.FindBufferContainingLoc(DiagLoc);
    unsigned CppHashBuf =
        Parser->SrcMgr.FindBufferContainingLoc(Parser->CppHashLoc);
  
    // Like SourceMgr::printMessage() we need to print the include stack if any
    // before printing the message.
    unsigned DiagCurBuffer = DiagSrcMgr.FindBufferContainingLoc(DiagLoc);
    if (!Parser->SavedDiagHandler && DiagCurBuffer &&
        DiagCurBuffer != DiagSrcMgr.getMainFileID()) {
      SMLoc ParentIncludeLoc = DiagSrcMgr.getParentIncludeLoc(DiagCurBuffer);
      DiagSrcMgr.PrintIncludeStack(ParentIncludeLoc, OS);
    }
  
    // If we have not parsed a cpp hash line filename comment or the source
    // manager changed or buffer changed (like in a nested include) then just
    // print the normal diagnostic using its Filename and LineNo.
    if (!Parser->CppHashLineNumber || &DiagSrcMgr != &Parser->SrcMgr ||
        DiagBuf != CppHashBuf) {
      if (Parser->SavedDiagHandler)
        Parser->SavedDiagHandler(Diag, Parser->SavedDiagContext);
      else
        Diag.print(nullptr, OS);
      return;
    }
  
    // Use the CppHashFilename and calculate a line number based on the
    // CppHashLoc and CppHashLineNumber relative to this Diag's SMLoc for
    // the diagnostic.
    const std::string &Filename = Parser->CppHashFilename;
  
    int DiagLocLineNo = DiagSrcMgr.FindLineNumber(DiagLoc, DiagBuf);
    int CppHashLocLineNo =
        Parser->SrcMgr.FindLineNumber(Parser->CppHashLoc, CppHashBuf);
    int LineNo =
        Parser->CppHashLineNumber - 1 + (DiagLocLineNo - CppHashLocLineNo);
  
    SMDiagnostic NewDiag(*Diag.getSourceMgr(), Diag.getLoc(), Filename, LineNo,
                         Diag.getColumnNo(), Diag.getKind(), Diag.getMessage(),
                         Diag.getLineContents(), Diag.getRanges());
  
    if (Parser->SavedDiagHandler)
      Parser->SavedDiagHandler(NewDiag, Parser->SavedDiagContext);
    else
      NewDiag.print(nullptr, OS);
  }
  
  // FIXME: This is mostly duplicated from the function in AsmLexer.cpp. The
  // difference being that that function accepts '@' as part of identifiers and
  // we can't do that. AsmLexer.cpp should probably be changed to handle
  // '@' as a special case when needed.
  static bool isIdentifierChar(char c) {
    return isalnum(static_cast<unsigned char>(c)) || c == '_' || c == '$' ||
           c == '.';
  }
  
  bool AsmParser::expandMacro(raw_svector_ostream &OS, StringRef Body,
                              ArrayRef<MCAsmMacroParameter> Parameters,
                              ArrayRef<MCAsmMacroArgument> A,
                              bool EnableAtPseudoVariable, SMLoc L) {
    unsigned NParameters = Parameters.size();
    bool HasVararg = NParameters ? Parameters.back().Vararg : false;
    if ((!IsDarwin || NParameters != 0) && NParameters != A.size())
      return Error(L, "Wrong number of arguments");
  
    // A macro without parameters is handled differently on Darwin:
    // gas accepts no arguments and does no substitutions
    while (!Body.empty()) {
      // Scan for the next substitution.
      std::size_t End = Body.size(), Pos = 0;
      for (; Pos != End; ++Pos) {
        // Check for a substitution or escape.
        if (IsDarwin && !NParameters) {
          // This macro has no parameters, look for $0, $1, etc.
          if (Body[Pos] != '$' || Pos + 1 == End)
            continue;
  
          char Next = Body[Pos + 1];
          if (Next == '$' || Next == 'n' ||
              isdigit(static_cast<unsigned char>(Next)))
            break;
        } else {
          // This macro has parameters, look for \foo, \bar, etc.
          if (Body[Pos] == '\\' && Pos + 1 != End)
            break;
        }
      }
  
      // Add the prefix.
      OS << Body.slice(0, Pos);
  
      // Check if we reached the end.
      if (Pos == End)
        break;
  
      if (IsDarwin && !NParameters) {
        switch (Body[Pos + 1]) {
        // $$ => $
        case '$':
          OS << '$';
          break;
  
        // $n => number of arguments
        case 'n':
          OS << A.size();
          break;
  
        // $[0-9] => argument
        default: {
          // Missing arguments are ignored.
          unsigned Index = Body[Pos + 1] - '0';
          if (Index >= A.size())
            break;
  
          // Otherwise substitute with the token values, with spaces eliminated.
          for (const AsmToken &Token : A[Index])
            OS << Token.getString();
          break;
        }
        }
        Pos += 2;
      } else {
        unsigned I = Pos + 1;
  
        // Check for the \@ pseudo-variable.
        if (EnableAtPseudoVariable && Body[I] == '@' && I + 1 != End)
          ++I;
        else
          while (isIdentifierChar(Body[I]) && I + 1 != End)
            ++I;
  
        const char *Begin = Body.data() + Pos + 1;
        StringRef Argument(Begin, I - (Pos + 1));
        unsigned Index = 0;
  
        if (Argument == "@") {
          OS << NumOfMacroInstantiations;
          Pos += 2;
        } else {
          for (; Index < NParameters; ++Index)
            if (Parameters[Index].Name == Argument)
              break;
  
          if (Index == NParameters) {
            if (Body[Pos + 1] == '(' && Body[Pos + 2] == ')')
              Pos += 3;
            else {
              OS << '\\' << Argument;
              Pos = I;
            }
          } else {
            bool VarargParameter = HasVararg && Index == (NParameters - 1);
            for (const AsmToken &Token : A[Index])
              // We expect no quotes around the string's contents when
              // parsing for varargs.
              if (Token.getKind() != AsmToken::String || VarargParameter)
                OS << Token.getString();
              else
                OS << Token.getStringContents();
  
            Pos += 1 + Argument.size();
          }
        }
      }
      // Update the scan point.
      Body = Body.substr(Pos);
    }
  
    return false;
  }
  
  MacroInstantiation::MacroInstantiation(SMLoc IL, int EB, SMLoc EL,
                                         size_t CondStackDepth)
      : InstantiationLoc(IL), ExitBuffer(EB), ExitLoc(EL),
        CondStackDepth(CondStackDepth) {}
  
  static bool isOperator(AsmToken::TokenKind kind) {
    switch (kind) {
    default:
      return false;
    case AsmToken::Plus:
    case AsmToken::Minus:
    case AsmToken::Tilde:
    case AsmToken::Slash:
    case AsmToken::Star:
    case AsmToken::Dot:
    case AsmToken::Equal:
    case AsmToken::EqualEqual:
    case AsmToken::Pipe:
    case AsmToken::PipePipe:
    case AsmToken::Caret:
    case AsmToken::Amp:
    case AsmToken::AmpAmp:
    case AsmToken::Exclaim:
    case AsmToken::ExclaimEqual:
    case AsmToken::Percent:
    case AsmToken::Less:
    case AsmToken::LessEqual:
    case AsmToken::LessLess:
    case AsmToken::LessGreater:
    case AsmToken::Greater:
    case AsmToken::GreaterEqual:
    case AsmToken::GreaterGreater:
      return true;
    }
  }
  
  namespace {
  class AsmLexerSkipSpaceRAII {
  public:
    AsmLexerSkipSpaceRAII(AsmLexer &Lexer, bool SkipSpace) : Lexer(Lexer) {
      Lexer.setSkipSpace(SkipSpace);
    }
  
    ~AsmLexerSkipSpaceRAII() {
      Lexer.setSkipSpace(true);
    }
  
  private:
    AsmLexer &Lexer;
  };
  }
  
  bool AsmParser::parseMacroArgument(MCAsmMacroArgument &MA, bool Vararg) {
  
    if (Vararg) {
      if (Lexer.isNot(AsmToken::EndOfStatement)) {
        StringRef Str = parseStringToEndOfStatement();
        MA.emplace_back(AsmToken::String, Str);
      }
      return false;
    }
  
    unsigned ParenLevel = 0;
    unsigned AddTokens = 0;
  
    // Darwin doesn't use spaces to delmit arguments.
    AsmLexerSkipSpaceRAII ScopedSkipSpace(Lexer, IsDarwin);
  
    for (;;) {
      if (Lexer.is(AsmToken::Eof) || Lexer.is(AsmToken::Equal))
        return TokError("unexpected token in macro instantiation");
  
      if (ParenLevel == 0 && Lexer.is(AsmToken::Comma))
        break;
  
      if (Lexer.is(AsmToken::Space)) {
        Lex(); // Eat spaces
  
        // Spaces can delimit parameters, but could also be part an expression.
        // If the token after a space is an operator, add the token and the next
        // one into this argument
        if (!IsDarwin) {
          if (isOperator(Lexer.getKind())) {
            // Check to see whether the token is used as an operator,
            // or part of an identifier
            const char *NextChar = getTok().getEndLoc().getPointer();
            if (*NextChar == ' ')
              AddTokens = 2;
          }
  
          if (!AddTokens && ParenLevel == 0) {
            break;
          }
        }
      }
  
      // handleMacroEntry relies on not advancing the lexer here
      // to be able to fill in the remaining default parameter values
      if (Lexer.is(AsmToken::EndOfStatement))
        break;
  
      // Adjust the current parentheses level.
      if (Lexer.is(AsmToken::LParen))
        ++ParenLevel;
      else if (Lexer.is(AsmToken::RParen) && ParenLevel)
        --ParenLevel;
  
      // Append the token to the current argument list.
      MA.push_back(getTok());
      if (AddTokens)
        AddTokens--;
      Lex();
    }
  
    if (ParenLevel != 0)
      return TokError("unbalanced parentheses in macro argument");
    return false;
  }
  
  // Parse the macro instantiation arguments.
  bool AsmParser::parseMacroArguments(const MCAsmMacro *M,
                                      MCAsmMacroArguments &A) {
    const unsigned NParameters = M ? M->Parameters.size() : 0;
    bool NamedParametersFound = false;
    SmallVector<SMLoc, 4> FALocs;
  
    A.resize(NParameters);
    FALocs.resize(NParameters);
  
    // Parse two kinds of macro invocations:
    // - macros defined without any parameters accept an arbitrary number of them
    // - macros defined with parameters accept at most that many of them
    bool HasVararg = NParameters ? M->Parameters.back().Vararg : false;
    for (unsigned Parameter = 0; !NParameters || Parameter < NParameters;
         ++Parameter) {
      SMLoc IDLoc = Lexer.getLoc();
      MCAsmMacroParameter FA;
  
      if (Lexer.is(AsmToken::Identifier) && Lexer.peekTok().is(AsmToken::Equal)) {
        if (parseIdentifier(FA.Name)) {
          Error(IDLoc, "invalid argument identifier for formal argument");
          eatToEndOfStatement();
          return true;
        }
  
        if (!Lexer.is(AsmToken::Equal)) {
          TokError("expected '=' after formal parameter identifier");
          eatToEndOfStatement();
          return true;
        }
        Lex();
  
        NamedParametersFound = true;
      }
  
      if (NamedParametersFound && FA.Name.empty()) {
        Error(IDLoc, "cannot mix positional and keyword arguments");
        eatToEndOfStatement();
        return true;
      }
  
      bool Vararg = HasVararg && Parameter == (NParameters - 1);
      if (parseMacroArgument(FA.Value, Vararg))
        return true;
  
      unsigned PI = Parameter;
      if (!FA.Name.empty()) {
        unsigned FAI = 0;
        for (FAI = 0; FAI < NParameters; ++FAI)
          if (M->Parameters[FAI].Name == FA.Name)
            break;
  
        if (FAI >= NParameters) {
      assert(M && "expected macro to be defined");
          Error(IDLoc,
                "parameter named '" + FA.Name + "' does not exist for macro '" +
                M->Name + "'");
          return true;
        }
        PI = FAI;
      }
  
      if (!FA.Value.empty()) {
        if (A.size() <= PI)
          A.resize(PI + 1);
        A[PI] = FA.Value;
  
        if (FALocs.size() <= PI)
          FALocs.resize(PI + 1);
  
        FALocs[PI] = Lexer.getLoc();
      }
  
      // At the end of the statement, fill in remaining arguments that have
      // default values. If there aren't any, then the next argument is
      // required but missing
      if (Lexer.is(AsmToken::EndOfStatement)) {
        bool Failure = false;
        for (unsigned FAI = 0; FAI < NParameters; ++FAI) {
          if (A[FAI].empty()) {
            if (M->Parameters[FAI].Required) {
              Error(FALocs[FAI].isValid() ? FALocs[FAI] : Lexer.getLoc(),
                    "missing value for required parameter "
                    "'" + M->Parameters[FAI].Name + "' in macro '" + M->Name + "'");
              Failure = true;
            }
  
            if (!M->Parameters[FAI].Value.empty())
              A[FAI] = M->Parameters[FAI].Value;
          }
        }
        return Failure;
      }
  
      if (Lexer.is(AsmToken::Comma))
        Lex();
    }
  
    return TokError("too many positional arguments");
  }
  
  const MCAsmMacro *AsmParser::lookupMacro(StringRef Name) {
    StringMap<MCAsmMacro>::iterator I = MacroMap.find(Name);
    return (I == MacroMap.end()) ? nullptr : &I->getValue();
  }
  
  void AsmParser::defineMacro(StringRef Name, MCAsmMacro Macro) {
    MacroMap.insert(std::make_pair(Name, std::move(Macro)));
  }
  
  void AsmParser::undefineMacro(StringRef Name) { MacroMap.erase(Name); }
  
  bool AsmParser::handleMacroEntry(const MCAsmMacro *M, SMLoc NameLoc) {
    // Arbitrarily limit macro nesting depth, to match 'as'. We can eliminate
    // this, although we should protect against infinite loops.
    if (ActiveMacros.size() == 20)
      return TokError("macros cannot be nested more than 20 levels deep");
  
    MCAsmMacroArguments A;
    if (parseMacroArguments(M, A))
      return true;
  
    // Macro instantiation is lexical, unfortunately. We construct a new buffer
    // to hold the macro body with substitutions.
    SmallString<256> Buf;
    StringRef Body = M->Body;
    raw_svector_ostream OS(Buf);
  
    if (expandMacro(OS, Body, M->Parameters, A, true, getTok().getLoc()))
      return true;
  
    // We include the .endmacro in the buffer as our cue to exit the macro
    // instantiation.
    OS << ".endmacro\n";
  
    std::unique_ptr<MemoryBuffer> Instantiation =
        MemoryBuffer::getMemBufferCopy(OS.str(), "<instantiation>");
  
    // Create the macro instantiation object and add to the current macro
    // instantiation stack.
    MacroInstantiation *MI = new MacroInstantiation(
        NameLoc, CurBuffer, getTok().getLoc(), TheCondStack.size());
    ActiveMacros.push_back(MI);
  
    ++NumOfMacroInstantiations;
  
    // Jump to the macro instantiation and prime the lexer.
    CurBuffer = SrcMgr.AddNewSourceBuffer(std::move(Instantiation), SMLoc());
    Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer());
    Lex();
  
    return false;
  }
  
  void AsmParser::handleMacroExit() {
    // Jump to the EndOfStatement we should return to, and consume it.
    jumpToLoc(ActiveMacros.back()->ExitLoc, ActiveMacros.back()->ExitBuffer);
    Lex();
  
    // Pop the instantiation entry.
    delete ActiveMacros.back();
    ActiveMacros.pop_back();
  }
  
  bool AsmParser::parseAssignment(StringRef Name, bool allow_redef,
                                  bool NoDeadStrip) {
    MCSymbol *Sym;
    const MCExpr *Value;
    if (MCParserUtils::parseAssignmentExpression(Name, allow_redef, *this, Sym,
                                                 Value))
      return true;
  
    if (!Sym) {
      // In the case where we parse an expression starting with a '.', we will
      // not generate an error, nor will we create a symbol.  In this case we
      // should just return out.
      return false;
    }
  
    // Do the assignment.
    Out.EmitAssignment(Sym, Value);
    if (NoDeadStrip)
      Out.EmitSymbolAttribute(Sym, MCSA_NoDeadStrip);
  
    return false;
  }
  
  /// parseIdentifier:
  ///   ::= identifier
  ///   ::= string
  bool AsmParser::parseIdentifier(StringRef &Res) {
    // The assembler has relaxed rules for accepting identifiers, in particular we
    // allow things like '.globl $foo' and '.def @feat.00', which would normally be
    // separate tokens. At this level, we have already lexed so we cannot (currently)
    // handle this as a context dependent token, instead we detect adjacent tokens
    // and return the combined identifier.
    if (Lexer.is(AsmToken::Dollar) || Lexer.is(AsmToken::At)) {
      SMLoc PrefixLoc = getLexer().getLoc();
  
      // Consume the prefix character, and check for a following identifier.
      Lex();
      if (Lexer.isNot(AsmToken::Identifier))
        return true;
  
      // We have a '$' or '@' followed by an identifier, make sure they are adjacent.
      if (PrefixLoc.getPointer() + 1 != getTok().getLoc().getPointer())
        return true;
  
      // Construct the joined identifier and consume the token.
      Res =
          StringRef(PrefixLoc.getPointer(), getTok().getIdentifier().size() + 1);
      Lex();
      return false;
    }
  
    if (Lexer.isNot(AsmToken::Identifier) && Lexer.isNot(AsmToken::String))
      return true;
  
    Res = getTok().getIdentifier();
  
    Lex(); // Consume the identifier token.
  
    return false;
  }
  
  /// parseDirectiveSet:
  ///   ::= .equ identifier ',' expression
  ///   ::= .equiv identifier ',' expression
  ///   ::= .set identifier ',' expression
  bool AsmParser::parseDirectiveSet(StringRef IDVal, bool allow_redef) {
    StringRef Name;
  
    if (parseIdentifier(Name))
      return TokError("expected identifier after '" + Twine(IDVal) + "'");
  
    if (getLexer().isNot(AsmToken::Comma))
      return TokError("unexpected token in '" + Twine(IDVal) + "'");
    Lex();
  
    return parseAssignment(Name, allow_redef, true);
  }
  
  bool AsmParser::parseEscapedString(std::string &Data) {
    assert(getLexer().is(AsmToken::String) && "Unexpected current token!");
  
    Data = "";
    StringRef Str = getTok().getStringContents();
    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
      if (Str[i] != '\\') {
        Data += Str[i];
        continue;
      }
  
      // Recognize escaped characters. Note that this escape semantics currently
      // loosely follows Darwin 'as'. Notably, it doesn't support hex escapes.
      ++i;
      if (i == e)
        return TokError("unexpected backslash at end of string");
  
      // Recognize octal sequences.
      if ((unsigned)(Str[i] - '0') <= 7) {
        // Consume up to three octal characters.
        unsigned Value = Str[i] - '0';
  
        if (i + 1 != e && ((unsigned)(Str[i + 1] - '0')) <= 7) {
          ++i;
          Value = Value * 8 + (Str[i] - '0');
  
          if (i + 1 != e && ((unsigned)(Str[i + 1] - '0')) <= 7) {
            ++i;
            Value = Value * 8 + (Str[i] - '0');
          }
        }
  
        if (Value > 255)
          return TokError("invalid octal escape sequence (out of range)");
  
        Data += (unsigned char)Value;
        continue;
      }
  
      // Otherwise recognize individual escapes.
      switch (Str[i]) {
      default:
        // Just reject invalid escape sequences for now.
        return TokError("invalid escape sequence (unrecognized character)");
  
      case 'b': Data += '\b'; break;
      case 'f': Data += '\f'; break;
      case 'n': Data += '\n'; break;
      case 'r': Data += '\r'; break;
      case 't': Data += '\t'; break;
      case '"': Data += '"'; break;
      case '\\': Data += '\\'; break;
      }
    }
  
    return false;
  }
  
  /// parseDirectiveAscii:
  ///   ::= ( .ascii | .asciz | .string ) [ "string" ( , "string" )* ]
  bool AsmParser::parseDirectiveAscii(StringRef IDVal, bool ZeroTerminated) {
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      checkForValidSection();
  
      for (;;) {
        if (getLexer().isNot(AsmToken::String))
          return TokError("expected string in '" + Twine(IDVal) + "' directive");
  
        std::string Data;
        if (parseEscapedString(Data))
          return true;
  
        getStreamer().EmitBytes(Data);
        if (ZeroTerminated)
          getStreamer().EmitBytes(StringRef("\0", 1));
  
        Lex();
  
        if (getLexer().is(AsmToken::EndOfStatement))
          break;
  
        if (getLexer().isNot(AsmToken::Comma))
          return TokError("unexpected token in '" + Twine(IDVal) + "' directive");
        Lex();
      }
    }
  
    Lex();
    return false;
  }
  
  /// parseDirectiveReloc
  ///  ::= .reloc expression , identifier [ , expression ]
  bool AsmParser::parseDirectiveReloc(SMLoc DirectiveLoc) {
    const MCExpr *Offset;
    const MCExpr *Expr = nullptr;
  
    SMLoc OffsetLoc = Lexer.getTok().getLoc();
    if (parseExpression(Offset))
      return true;
  
    // We can only deal with constant expressions at the moment.
    int64_t OffsetValue;
    if (!Offset->evaluateAsAbsolute(OffsetValue))
      return Error(OffsetLoc, "expression is not a constant value");
  
    if (OffsetValue < 0)
      return Error(OffsetLoc, "expression is negative");
  
    if (Lexer.isNot(AsmToken::Comma))
      return TokError("expected comma");
    Lexer.Lex();
  
    if (Lexer.isNot(AsmToken::Identifier))
      return TokError("expected relocation name");
    SMLoc NameLoc = Lexer.getTok().getLoc();
    StringRef Name = Lexer.getTok().getIdentifier();
    Lexer.Lex();
  
    if (Lexer.is(AsmToken::Comma)) {
      Lexer.Lex();
      SMLoc ExprLoc = Lexer.getLoc();
      if (parseExpression(Expr))
        return true;
  
      MCValue Value;
      if (!Expr->evaluateAsRelocatable(Value, nullptr, nullptr))
        return Error(ExprLoc, "expression must be relocatable");
    }
  
    if (Lexer.isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in .reloc directive");
  
    if (getStreamer().EmitRelocDirective(*Offset, Name, Expr, DirectiveLoc))
      return Error(NameLoc, "unknown relocation name");
  
    return false;
  }
  
  /// parseDirectiveValue
  ///  ::= (.byte | .short | ... ) [ expression (, expression)* ]
  bool AsmParser::parseDirectiveValue(unsigned Size) {
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      checkForValidSection();
  
      for (;;) {
        const MCExpr *Value;
        SMLoc ExprLoc = getLexer().getLoc();
        if (parseExpression(Value))
          return true;
  
        // Special case constant expressions to match code generator.
        if (const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(Value)) {
          assert(Size <= 8 && "Invalid size");
          uint64_t IntValue = MCE->getValue();
          if (!isUIntN(8 * Size, IntValue) && !isIntN(8 * Size, IntValue))
            return Error(ExprLoc, "literal value out of range for directive");
          getStreamer().EmitIntValue(IntValue, Size);
        } else
          getStreamer().EmitValue(Value, Size, ExprLoc);
  
        if (getLexer().is(AsmToken::EndOfStatement))
          break;
  
        // FIXME: Improve diagnostic.
        if (getLexer().isNot(AsmToken::Comma))
          return TokError("unexpected token in directive");
        Lex();
      }
    }
  
    Lex();
    return false;
  }
  
  /// ParseDirectiveOctaValue
  ///  ::= .octa [ hexconstant (, hexconstant)* ]
  bool AsmParser::parseDirectiveOctaValue() {
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      checkForValidSection();
  
      for (;;) {
        if (Lexer.getKind() == AsmToken::Error)
          return true;
        if (Lexer.getKind() != AsmToken::Integer &&
            Lexer.getKind() != AsmToken::BigNum)
          return TokError("unknown token in expression");
  
        SMLoc ExprLoc = getLexer().getLoc();
        APInt IntValue = getTok().getAPIntVal();
        Lex();
  
        uint64_t hi, lo;
        if (IntValue.isIntN(64)) {
          hi = 0;
          lo = IntValue.getZExtValue();
        } else if (IntValue.isIntN(128)) {
          // It might actually have more than 128 bits, but the top ones are zero.
          hi = IntValue.getHiBits(IntValue.getBitWidth() - 64).getZExtValue();
          lo = IntValue.getLoBits(64).getZExtValue();
        } else
          return Error(ExprLoc, "literal value out of range for directive");
  
        if (MAI.isLittleEndian()) {
          getStreamer().EmitIntValue(lo, 8);
          getStreamer().EmitIntValue(hi, 8);
        } else {
          getStreamer().EmitIntValue(hi, 8);
          getStreamer().EmitIntValue(lo, 8);
        }
  
        if (getLexer().is(AsmToken::EndOfStatement))
          break;
  
        // FIXME: Improve diagnostic.
        if (getLexer().isNot(AsmToken::Comma))
          return TokError("unexpected token in directive");
        Lex();
      }
    }
  
    Lex();
    return false;
  }
  
  /// parseDirectiveRealValue
  ///  ::= (.single | .double) [ expression (, expression)* ]
  bool AsmParser::parseDirectiveRealValue(const fltSemantics &Semantics) {
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      checkForValidSection();
  
      for (;;) {
        // We don't truly support arithmetic on floating point expressions, so we
        // have to manually parse unary prefixes.
        bool IsNeg = false;
        if (getLexer().is(AsmToken::Minus)) {
          Lex();
          IsNeg = true;
        } else if (getLexer().is(AsmToken::Plus))
          Lex();
  
        if (getLexer().isNot(AsmToken::Integer) &&
            getLexer().isNot(AsmToken::Real) &&
            getLexer().isNot(AsmToken::Identifier))
          return TokError("unexpected token in directive");
  
        // Convert to an APFloat.
        APFloat Value(Semantics);
        StringRef IDVal = getTok().getString();
        if (getLexer().is(AsmToken::Identifier)) {
          if (!IDVal.compare_lower("infinity") || !IDVal.compare_lower("inf"))
            Value = APFloat::getInf(Semantics);
          else if (!IDVal.compare_lower("nan"))
            Value = APFloat::getNaN(Semantics, false, ~0);
          else
            return TokError("invalid floating point literal");
        } else if (Value.convertFromString(IDVal, APFloat::rmNearestTiesToEven) ==
                   APFloat::opInvalidOp)
          return TokError("invalid floating point literal");
        if (IsNeg)
          Value.changeSign();
  
        // Consume the numeric token.
        Lex();
  
        // Emit the value as an integer.
        APInt AsInt = Value.bitcastToAPInt();
        getStreamer().EmitIntValue(AsInt.getLimitedValue(),
                                   AsInt.getBitWidth() / 8);
  
        if (getLexer().is(AsmToken::EndOfStatement))
          break;
  
        if (getLexer().isNot(AsmToken::Comma))
          return TokError("unexpected token in directive");
        Lex();
      }
    }
  
    Lex();
    return false;
  }
  
  /// parseDirectiveZero
  ///  ::= .zero expression
  bool AsmParser::parseDirectiveZero() {
    checkForValidSection();
  
    int64_t NumBytes;
    if (parseAbsoluteExpression(NumBytes))
      return true;
  
    int64_t Val = 0;
    if (getLexer().is(AsmToken::Comma)) {
      Lex();
      if (parseAbsoluteExpression(Val))
        return true;
    }
  
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.zero' directive");
  
    Lex();
  
    getStreamer().EmitFill(NumBytes, Val);
  
    return false;
  }
  
  /// parseDirectiveFill
  ///  ::= .fill expression [ , expression [ , expression ] ]
  bool AsmParser::parseDirectiveFill() {
    checkForValidSection();
  
    SMLoc RepeatLoc = getLexer().getLoc();
    int64_t NumValues;
    if (parseAbsoluteExpression(NumValues))
      return true;
  
    if (NumValues < 0) {
      Warning(RepeatLoc,
              "'.fill' directive with negative repeat count has no effect");
      NumValues = 0;
    }
  
    int64_t FillSize = 1;
    int64_t FillExpr = 0;
  
    SMLoc SizeLoc, ExprLoc;
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      if (getLexer().isNot(AsmToken::Comma))
        return TokError("unexpected token in '.fill' directive");
      Lex();
  
      SizeLoc = getLexer().getLoc();
      if (parseAbsoluteExpression(FillSize))
        return true;
  
      if (getLexer().isNot(AsmToken::EndOfStatement)) {
        if (getLexer().isNot(AsmToken::Comma))
          return TokError("unexpected token in '.fill' directive");
        Lex();
  
        ExprLoc = getLexer().getLoc();
        if (parseAbsoluteExpression(FillExpr))
          return true;
  
        if (getLexer().isNot(AsmToken::EndOfStatement))
          return TokError("unexpected token in '.fill' directive");
  
        Lex();
      }
    }
  
    if (FillSize < 0) {
      Warning(SizeLoc, "'.fill' directive with negative size has no effect");
      NumValues = 0;
    }
    if (FillSize > 8) {
      Warning(SizeLoc, "'.fill' directive with size greater than 8 has been truncated to 8");
      FillSize = 8;
    }
  
    if (!isUInt<32>(FillExpr) && FillSize > 4)
      Warning(ExprLoc, "'.fill' directive pattern has been truncated to 32-bits");
  
    if (NumValues > 0) {
      int64_t NonZeroFillSize = FillSize > 4 ? 4 : FillSize;
      FillExpr &= ~0ULL >> (64 - NonZeroFillSize * 8);
      for (uint64_t i = 0, e = NumValues; i != e; ++i) {
        getStreamer().EmitIntValue(FillExpr, NonZeroFillSize);
        if (NonZeroFillSize < FillSize)
          getStreamer().EmitIntValue(0, FillSize - NonZeroFillSize);
      }
    }
  
    return false;
  }
  
  /// parseDirectiveOrg
  ///  ::= .org expression [ , expression ]
  bool AsmParser::parseDirectiveOrg() {
    checkForValidSection();
  
    const MCExpr *Offset;
    if (parseExpression(Offset))
      return true;
  
    // Parse optional fill expression.
    int64_t FillExpr = 0;
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      if (getLexer().isNot(AsmToken::Comma))
        return TokError("unexpected token in '.org' directive");
      Lex();
  
      if (parseAbsoluteExpression(FillExpr))
        return true;
  
      if (getLexer().isNot(AsmToken::EndOfStatement))
        return TokError("unexpected token in '.org' directive");
    }
  
    Lex();
    getStreamer().emitValueToOffset(Offset, FillExpr);
    return false;
  }
  
  /// parseDirectiveAlign
  ///  ::= {.align, ...} expression [ , expression [ , expression ]]
  bool AsmParser::parseDirectiveAlign(bool IsPow2, unsigned ValueSize) {
    checkForValidSection();
  
    SMLoc AlignmentLoc = getLexer().getLoc();
    int64_t Alignment;
    if (parseAbsoluteExpression(Alignment))
      return true;
  
    SMLoc MaxBytesLoc;
    bool HasFillExpr = false;
    int64_t FillExpr = 0;
    int64_t MaxBytesToFill = 0;
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      if (getLexer().isNot(AsmToken::Comma))
        return TokError("unexpected token in directive");
      Lex();
  
      // The fill expression can be omitted while specifying a maximum number of
      // alignment bytes, e.g:
      //  .align 3,,4
      if (getLexer().isNot(AsmToken::Comma)) {
        HasFillExpr = true;
        if (parseAbsoluteExpression(FillExpr))
          return true;
      }
  
      if (getLexer().isNot(AsmToken::EndOfStatement)) {
        if (getLexer().isNot(AsmToken::Comma))
          return TokError("unexpected token in directive");
        Lex();
  
        MaxBytesLoc = getLexer().getLoc();
        if (parseAbsoluteExpression(MaxBytesToFill))
          return true;
  
        if (getLexer().isNot(AsmToken::EndOfStatement))
          return TokError("unexpected token in directive");
      }
    }
  
    Lex();
  
    if (!HasFillExpr)
      FillExpr = 0;
  
    // Compute alignment in bytes.
    if (IsPow2) {
      // FIXME: Diagnose overflow.
      if (Alignment >= 32) {
        Error(AlignmentLoc, "invalid alignment value");
        Alignment = 31;
      }
  
      Alignment = 1ULL << Alignment;
    } else {
      // Reject alignments that aren't either a power of two or zero,
      // for gas compatibility. Alignment of zero is silently rounded
      // up to one.
      if (Alignment == 0)
        Alignment = 1;
      if (!isPowerOf2_64(Alignment))
        Error(AlignmentLoc, "alignment must be a power of 2");
    }
  
    // Diagnose non-sensical max bytes to align.
    if (MaxBytesLoc.isValid()) {
      if (MaxBytesToFill < 1) {
        Error(MaxBytesLoc, "alignment directive can never be satisfied in this "
                           "many bytes, ignoring maximum bytes expression");
        MaxBytesToFill = 0;
      }
  
      if (MaxBytesToFill >= Alignment) {
        Warning(MaxBytesLoc, "maximum bytes expression exceeds alignment and "
                             "has no effect");
        MaxBytesToFill = 0;
      }
    }
  
    // Check whether we should use optimal code alignment for this .align
    // directive.
    const MCSection *Section = getStreamer().getCurrentSection().first;
    assert(Section && "must have section to emit alignment");
    bool UseCodeAlign = Section->UseCodeAlign();
    if ((!HasFillExpr || Lexer.getMAI().getTextAlignFillValue() == FillExpr) &&
        ValueSize == 1 && UseCodeAlign) {
      getStreamer().EmitCodeAlignment(Alignment, MaxBytesToFill);
    } else {
      // FIXME: Target specific behavior about how the "extra" bytes are filled.
      getStreamer().EmitValueToAlignment(Alignment, FillExpr, ValueSize,
                                         MaxBytesToFill);
    }
  
    return false;
  }
  
  /// parseDirectiveFile
  /// ::= .file [number] filename
  /// ::= .file number directory filename
  bool AsmParser::parseDirectiveFile(SMLoc DirectiveLoc) {
    // FIXME: I'm not sure what this is.
    int64_t FileNumber = -1;
    SMLoc FileNumberLoc = getLexer().getLoc();
    if (getLexer().is(AsmToken::Integer)) {
      FileNumber = getTok().getIntVal();
      Lex();
  
      if (FileNumber < 1)
        return TokError("file number less than one");
    }
  
    if (getLexer().isNot(AsmToken::String))
      return TokError("unexpected token in '.file' directive");
  
    // Usually the directory and filename together, otherwise just the directory.
    // Allow the strings to have escaped octal character sequence.
    std::string Path = getTok().getString();
    if (parseEscapedString(Path))
      return true;
    Lex();
  
    StringRef Directory;
    StringRef Filename;
    std::string FilenameData;
    if (getLexer().is(AsmToken::String)) {
      if (FileNumber == -1)
        return TokError("explicit path specified, but no file number");
      if (parseEscapedString(FilenameData))
        return true;
      Filename = FilenameData;
      Directory = Path;
      Lex();
    } else {
      Filename = Path;
    }
  
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.file' directive");
  
    if (FileNumber == -1)
      getStreamer().EmitFileDirective(Filename);
    else {
      if (getContext().getGenDwarfForAssembly())
        Error(DirectiveLoc,
              "input can't have .file dwarf directives when -g is "
              "used to generate dwarf debug info for assembly code");
  
      if (getStreamer().EmitDwarfFileDirective(FileNumber, Directory, Filename) ==
          0)
        Error(FileNumberLoc, "file number already allocated");
    }
  
    return false;
  }
  
  /// parseDirectiveLine
  /// ::= .line [number]
  bool AsmParser::parseDirectiveLine() {
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      if (getLexer().isNot(AsmToken::Integer))
        return TokError("unexpected token in '.line' directive");
  
      int64_t LineNumber = getTok().getIntVal();
      (void)LineNumber;
      Lex();
  
      // FIXME: Do something with the .line.
    }
  
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.line' directive");
  
    return false;
  }
  
  /// parseDirectiveLoc
  /// ::= .loc FileNumber [LineNumber] [ColumnPos] [basic_block] [prologue_end]
  ///                                [epilogue_begin] [is_stmt VALUE] [isa VALUE]
  /// The first number is a file number, must have been previously assigned with
  /// a .file directive, the second number is the line number and optionally the
  /// third number is a column position (zero if not specified).  The remaining
  /// optional items are .loc sub-directives.
  bool AsmParser::parseDirectiveLoc() {
    if (getLexer().isNot(AsmToken::Integer))
      return TokError("unexpected token in '.loc' directive");
    int64_t FileNumber = getTok().getIntVal();
    if (FileNumber < 1)
      return TokError("file number less than one in '.loc' directive");
    if (!getContext().isValidDwarfFileNumber(FileNumber))
      return TokError("unassigned file number in '.loc' directive");
    Lex();
  
    int64_t LineNumber = 0;
    if (getLexer().is(AsmToken::Integer)) {
      LineNumber = getTok().getIntVal();
      if (LineNumber < 0)
        return TokError("line number less than zero in '.loc' directive");
      Lex();
    }
  
    int64_t ColumnPos = 0;
    if (getLexer().is(AsmToken::Integer)) {
      ColumnPos = getTok().getIntVal();
      if (ColumnPos < 0)
        return TokError("column position less than zero in '.loc' directive");
      Lex();
    }
  
    unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
    unsigned Isa = 0;
    int64_t Discriminator = 0;
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      for (;;) {
        if (getLexer().is(AsmToken::EndOfStatement))
          break;
  
        StringRef Name;
        SMLoc Loc = getTok().getLoc();
        if (parseIdentifier(Name))
          return TokError("unexpected token in '.loc' directive");
  
        if (Name == "basic_block")
          Flags |= DWARF2_FLAG_BASIC_BLOCK;
        else if (Name == "prologue_end")
          Flags |= DWARF2_FLAG_PROLOGUE_END;
        else if (Name == "epilogue_begin")
          Flags |= DWARF2_FLAG_EPILOGUE_BEGIN;
        else if (Name == "is_stmt") {
          Loc = getTok().getLoc();
          const MCExpr *Value;
          if (parseExpression(Value))
            return true;
          // The expression must be the constant 0 or 1.
          if (const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(Value)) {
            int Value = MCE->getValue();
            if (Value == 0)
              Flags &= ~DWARF2_FLAG_IS_STMT;
            else if (Value == 1)
              Flags |= DWARF2_FLAG_IS_STMT;
            else
              return Error(Loc, "is_stmt value not 0 or 1");
          } else {
            return Error(Loc, "is_stmt value not the constant value of 0 or 1");
          }
        } else if (Name == "isa") {
          Loc = getTok().getLoc();
          const MCExpr *Value;
          if (parseExpression(Value))
            return true;
          // The expression must be a constant greater or equal to 0.
          if (const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(Value)) {
            int Value = MCE->getValue();
            if (Value < 0)
              return Error(Loc, "isa number less than zero");
            Isa = Value;
          } else {
            return Error(Loc, "isa number not a constant value");
          }
        } else if (Name == "discriminator") {
          if (parseAbsoluteExpression(Discriminator))
            return true;
        } else {
          return Error(Loc, "unknown sub-directive in '.loc' directive");
        }
  
        if (getLexer().is(AsmToken::EndOfStatement))
          break;
      }
    }
  
    getStreamer().EmitDwarfLocDirective(FileNumber, LineNumber, ColumnPos, Flags,
                                        Isa, Discriminator, StringRef());
  
    return false;
  }
  
  /// parseDirectiveStabs
  /// ::= .stabs string, number, number, number
  bool AsmParser::parseDirectiveStabs() {
    return TokError("unsupported directive '.stabs'");
  }
  
  /// parseDirectiveCVFile
  /// ::= .cv_file number filename
  bool AsmParser::parseDirectiveCVFile() {
    SMLoc FileNumberLoc = getLexer().getLoc();
    if (getLexer().isNot(AsmToken::Integer))
      return TokError("expected file number in '.cv_file' directive");
  
    int64_t FileNumber = getTok().getIntVal();
    Lex();
  
    if (FileNumber < 1)
      return TokError("file number less than one");
  
    if (getLexer().isNot(AsmToken::String))
      return TokError("unexpected token in '.cv_file' directive");
  
    // Usually the directory and filename together, otherwise just the directory.
    // Allow the strings to have escaped octal character sequence.
    std::string Filename;
    if (parseEscapedString(Filename))
      return true;
    Lex();
  
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.cv_file' directive");
  
    if (getStreamer().EmitCVFileDirective(FileNumber, Filename) == 0)
      Error(FileNumberLoc, "file number already allocated");
  
    return false;
  }
  
  /// parseDirectiveCVLoc
  /// ::= .cv_loc FunctionId FileNumber [LineNumber] [ColumnPos] [prologue_end]
  ///                                [is_stmt VALUE]
  /// The first number is a file number, must have been previously assigned with
  /// a .file directive, the second number is the line number and optionally the
  /// third number is a column position (zero if not specified).  The remaining
  /// optional items are .loc sub-directives.
  bool AsmParser::parseDirectiveCVLoc() {
    if (getLexer().isNot(AsmToken::Integer))
      return TokError("unexpected token in '.cv_loc' directive");
  
    int64_t FunctionId = getTok().getIntVal();
    if (FunctionId < 0)
      return TokError("function id less than zero in '.cv_loc' directive");
    Lex();
  
    int64_t FileNumber = getTok().getIntVal();
    if (FileNumber < 1)
      return TokError("file number less than one in '.cv_loc' directive");
    if (!getContext().isValidCVFileNumber(FileNumber))
      return TokError("unassigned file number in '.cv_loc' directive");
    Lex();
  
    int64_t LineNumber = 0;
    if (getLexer().is(AsmToken::Integer)) {
      LineNumber = getTok().getIntVal();
      if (LineNumber < 0)
        return TokError("line number less than zero in '.cv_loc' directive");
      Lex();
    }
  
    int64_t ColumnPos = 0;
    if (getLexer().is(AsmToken::Integer)) {
      ColumnPos = getTok().getIntVal();
      if (ColumnPos < 0)
        return TokError("column position less than zero in '.cv_loc' directive");
      Lex();
    }
  
    bool PrologueEnd = false;
    uint64_t IsStmt = 0;
    while (getLexer().isNot(AsmToken::EndOfStatement)) {
      StringRef Name;
      SMLoc Loc = getTok().getLoc();
      if (parseIdentifier(Name))
        return TokError("unexpected token in '.cv_loc' directive");
  
      if (Name == "prologue_end")
        PrologueEnd = true;
      else if (Name == "is_stmt") {
        Loc = getTok().getLoc();
        const MCExpr *Value;
        if (parseExpression(Value))
          return true;
        // The expression must be the constant 0 or 1.
        IsStmt = ~0ULL;
        if (const auto *MCE = dyn_cast<MCConstantExpr>(Value))
          IsStmt = MCE->getValue();
  
        if (IsStmt > 1)
          return Error(Loc, "is_stmt value not 0 or 1");
      } else {
        return Error(Loc, "unknown sub-directive in '.cv_loc' directive");
      }
    }
  
    getStreamer().EmitCVLocDirective(FunctionId, FileNumber, LineNumber,
                                     ColumnPos, PrologueEnd, IsStmt, StringRef());
    return false;
  }
  
  /// parseDirectiveCVLinetable
  /// ::= .cv_linetable FunctionId, FnStart, FnEnd
  bool AsmParser::parseDirectiveCVLinetable() {
    int64_t FunctionId = getTok().getIntVal();
    if (FunctionId < 0)
      return TokError("function id less than zero in '.cv_linetable' directive");
    Lex();
  
    if (Lexer.isNot(AsmToken::Comma))
      return TokError("unexpected token in '.cv_linetable' directive");
    Lex();
  
    SMLoc Loc = getLexer().getLoc();
    StringRef FnStartName;
    if (parseIdentifier(FnStartName))
      return Error(Loc, "expected identifier in directive");
  
    if (Lexer.isNot(AsmToken::Comma))
      return TokError("unexpected token in '.cv_linetable' directive");
    Lex();
  
    Loc = getLexer().getLoc();
    StringRef FnEndName;
    if (parseIdentifier(FnEndName))
      return Error(Loc, "expected identifier in directive");
  
    MCSymbol *FnStartSym = getContext().getOrCreateSymbol(FnStartName);
    MCSymbol *FnEndSym = getContext().getOrCreateSymbol(FnEndName);
  
    getStreamer().EmitCVLinetableDirective(FunctionId, FnStartSym, FnEndSym);
    return false;
  }
  
  /// parseDirectiveCVInlineLinetable
  /// ::= .cv_inline_linetable PrimaryFunctionId FileId LineNum FnStart FnEnd
  ///          ("contains" SecondaryFunctionId+)?
  bool AsmParser::parseDirectiveCVInlineLinetable() {
    int64_t PrimaryFunctionId = getTok().getIntVal();
    if (PrimaryFunctionId < 0)
      return TokError(
          "function id less than zero in '.cv_inline_linetable' directive");
    Lex();
  
    int64_t SourceFileId = getTok().getIntVal();
    if (SourceFileId <= 0)
      return TokError(
          "File id less than zero in '.cv_inline_linetable' directive");
    Lex();
  
    int64_t SourceLineNum = getTok().getIntVal();
    if (SourceLineNum < 0)
      return TokError(
          "Line number less than zero in '.cv_inline_linetable' directive");
    Lex();
  
    SMLoc Loc = getLexer().getLoc();
    StringRef FnStartName;
    if (parseIdentifier(FnStartName))
      return Error(Loc, "expected identifier in directive");
    MCSymbol *FnStartSym = getContext().getOrCreateSymbol(FnStartName);
  
    Loc = getLexer().getLoc();
    StringRef FnEndName;
    if (parseIdentifier(FnEndName))
      return Error(Loc, "expected identifier in directive");
    MCSymbol *FnEndSym = getContext().getOrCreateSymbol(FnEndName);
  
    SmallVector<unsigned, 8> SecondaryFunctionIds;
    if (getLexer().is(AsmToken::Identifier)) {
      if (getTok().getIdentifier() != "contains")
        return TokError(
            "unexpected identifier in '.cv_inline_linetable' directive");
      Lex();
  
      while (getLexer().isNot(AsmToken::EndOfStatement)) {
        int64_t SecondaryFunctionId = getTok().getIntVal();
        if (SecondaryFunctionId < 0)
          return TokError(
              "function id less than zero in '.cv_inline_linetable' directive");
        Lex();
  
        SecondaryFunctionIds.push_back(SecondaryFunctionId);
      }
    }
  
    getStreamer().EmitCVInlineLinetableDirective(PrimaryFunctionId, SourceFileId,
                                                 SourceLineNum, FnStartSym,
                                                 FnEndSym, SecondaryFunctionIds);
    return false;
  }
  
  /// parseDirectiveCVStringTable
  /// ::= .cv_stringtable
  bool AsmParser::parseDirectiveCVStringTable() {
    getStreamer().EmitCVStringTableDirective();
    return false;
  }
  
  /// parseDirectiveCVFileChecksums
  /// ::= .cv_filechecksums
  bool AsmParser::parseDirectiveCVFileChecksums() {
    getStreamer().EmitCVFileChecksumsDirective();
    return false;
  }
  
  /// parseDirectiveCFISections
  /// ::= .cfi_sections section [, section]
  bool AsmParser::parseDirectiveCFISections() {
    StringRef Name;
    bool EH = false;
    bool Debug = false;
  
    if (parseIdentifier(Name))
      return TokError("Expected an identifier");
  
    if (Name == ".eh_frame")
      EH = true;
    else if (Name == ".debug_frame")
      Debug = true;
  
    if (getLexer().is(AsmToken::Comma)) {
      Lex();
  
      if (parseIdentifier(Name))
        return TokError("Expected an identifier");
  
      if (Name == ".eh_frame")
        EH = true;
      else if (Name == ".debug_frame")
        Debug = true;
    }
  
    getStreamer().EmitCFISections(EH, Debug);
    return false;
  }
  
  /// parseDirectiveCFIStartProc
  /// ::= .cfi_startproc [simple]
  bool AsmParser::parseDirectiveCFIStartProc() {
    StringRef Simple;
    if (getLexer().isNot(AsmToken::EndOfStatement))
      if (parseIdentifier(Simple) || Simple != "simple")
        return TokError("unexpected token in .cfi_startproc directive");
  
    getStreamer().EmitCFIStartProc(!Simple.empty());
    return false;
  }
  
  /// parseDirectiveCFIEndProc
  /// ::= .cfi_endproc
  bool AsmParser::parseDirectiveCFIEndProc() {
    getStreamer().EmitCFIEndProc();
    return false;
  }
  
  /// \brief parse register name or number.
  bool AsmParser::parseRegisterOrRegisterNumber(int64_t &Register,
                                                SMLoc DirectiveLoc) {
    unsigned RegNo;
  
    if (getLexer().isNot(AsmToken::Integer)) {
      if (getTargetParser().ParseRegister(RegNo, DirectiveLoc, DirectiveLoc))
        return true;
      Register = getContext().getRegisterInfo()->getDwarfRegNum(RegNo, true);
    } else
      return parseAbsoluteExpression(Register);
  
    return false;
  }
  
  /// parseDirectiveCFIDefCfa
  /// ::= .cfi_def_cfa register,  offset
  bool AsmParser::parseDirectiveCFIDefCfa(SMLoc DirectiveLoc) {
    int64_t Register = 0;
    if (parseRegisterOrRegisterNumber(Register, DirectiveLoc))
      return true;
  
    if (getLexer().isNot(AsmToken::Comma))
      return TokError("unexpected token in directive");
    Lex();
  
    int64_t Offset = 0;
    if (parseAbsoluteExpression(Offset))
      return true;
  
    getStreamer().EmitCFIDefCfa(Register, Offset);
    return false;
  }
  
  /// parseDirectiveCFIDefCfaOffset
  /// ::= .cfi_def_cfa_offset offset
  bool AsmParser::parseDirectiveCFIDefCfaOffset() {
    int64_t Offset = 0;
    if (parseAbsoluteExpression(Offset))
      return true;
  
    getStreamer().EmitCFIDefCfaOffset(Offset);
    return false;
  }
  
  /// parseDirectiveCFIRegister
  /// ::= .cfi_register register, register
  bool AsmParser::parseDirectiveCFIRegister(SMLoc DirectiveLoc) {
    int64_t Register1 = 0;
    if (parseRegisterOrRegisterNumber(Register1, DirectiveLoc))
      return true;
  
    if (getLexer().isNot(AsmToken::Comma))
      return TokError("unexpected token in directive");
    Lex();
  
    int64_t Register2 = 0;
    if (parseRegisterOrRegisterNumber(Register2, DirectiveLoc))
      return true;
  
    getStreamer().EmitCFIRegister(Register1, Register2);
    return false;
  }
  
  /// parseDirectiveCFIWindowSave
  /// ::= .cfi_window_save
  bool AsmParser::parseDirectiveCFIWindowSave() {
    getStreamer().EmitCFIWindowSave();
    return false;
  }
  
  /// parseDirectiveCFIAdjustCfaOffset
  /// ::= .cfi_adjust_cfa_offset adjustment
  bool AsmParser::parseDirectiveCFIAdjustCfaOffset() {
    int64_t Adjustment = 0;
    if (parseAbsoluteExpression(Adjustment))
      return true;
  
    getStreamer().EmitCFIAdjustCfaOffset(Adjustment);
    return false;
  }
  
  /// parseDirectiveCFIDefCfaRegister
  /// ::= .cfi_def_cfa_register register
  bool AsmParser::parseDirectiveCFIDefCfaRegister(SMLoc DirectiveLoc) {
    int64_t Register = 0;
    if (parseRegisterOrRegisterNumber(Register, DirectiveLoc))
      return true;
  
    getStreamer().EmitCFIDefCfaRegister(Register);
    return false;
  }
  
  /// parseDirectiveCFIOffset
  /// ::= .cfi_offset register, offset
  bool AsmParser::parseDirectiveCFIOffset(SMLoc DirectiveLoc) {
    int64_t Register = 0;
    int64_t Offset = 0;
  
    if (parseRegisterOrRegisterNumber(Register, DirectiveLoc))
      return true;
  
    if (getLexer().isNot(AsmToken::Comma))
      return TokError("unexpected token in directive");
    Lex();
  
    if (parseAbsoluteExpression(Offset))
      return true;
  
    getStreamer().EmitCFIOffset(Register, Offset);
    return false;
  }
  
  /// parseDirectiveCFIRelOffset
  /// ::= .cfi_rel_offset register, offset
  bool AsmParser::parseDirectiveCFIRelOffset(SMLoc DirectiveLoc) {
    int64_t Register = 0;
  
    if (parseRegisterOrRegisterNumber(Register, DirectiveLoc))
      return true;
  
    if (getLexer().isNot(AsmToken::Comma))
      return TokError("unexpected token in directive");
    Lex();
  
    int64_t Offset = 0;
    if (parseAbsoluteExpression(Offset))
      return true;
  
    getStreamer().EmitCFIRelOffset(Register, Offset);
    return false;
  }
  
  static bool isValidEncoding(int64_t Encoding) {
    if (Encoding & ~0xff)
      return false;
  
    if (Encoding == dwarf::DW_EH_PE_omit)
      return true;
  
    const unsigned Format = Encoding & 0xf;
    if (Format != dwarf::DW_EH_PE_absptr && Format != dwarf::DW_EH_PE_udata2 &&
        Format != dwarf::DW_EH_PE_udata4 && Format != dwarf::DW_EH_PE_udata8 &&
        Format != dwarf::DW_EH_PE_sdata2 && Format != dwarf::DW_EH_PE_sdata4 &&
        Format != dwarf::DW_EH_PE_sdata8 && Format != dwarf::DW_EH_PE_signed)
      return false;
  
    const unsigned Application = Encoding & 0x70;
    if (Application != dwarf::DW_EH_PE_absptr &&
        Application != dwarf::DW_EH_PE_pcrel)
      return false;
  
    return true;
  }
  
  /// parseDirectiveCFIPersonalityOrLsda
  /// IsPersonality true for cfi_personality, false for cfi_lsda
  /// ::= .cfi_personality encoding, [symbol_name]
  /// ::= .cfi_lsda encoding, [symbol_name]
  bool AsmParser::parseDirectiveCFIPersonalityOrLsda(bool IsPersonality) {
    int64_t Encoding = 0;
    if (parseAbsoluteExpression(Encoding))
      return true;
    if (Encoding == dwarf::DW_EH_PE_omit)
      return false;
  
    if (!isValidEncoding(Encoding))
      return TokError("unsupported encoding.");
  
    if (getLexer().isNot(AsmToken::Comma))
      return TokError("unexpected token in directive");
    Lex();
  
    StringRef Name;
    if (parseIdentifier(Name))
      return TokError("expected identifier in directive");
  
    MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
  
    if (IsPersonality)
      getStreamer().EmitCFIPersonality(Sym, Encoding);
    else
      getStreamer().EmitCFILsda(Sym, Encoding);
    return false;
  }
  
  /// parseDirectiveCFIRememberState
  /// ::= .cfi_remember_state
  bool AsmParser::parseDirectiveCFIRememberState() {
    getStreamer().EmitCFIRememberState();
    return false;
  }
  
  /// parseDirectiveCFIRestoreState
  /// ::= .cfi_remember_state
  bool AsmParser::parseDirectiveCFIRestoreState() {
    getStreamer().EmitCFIRestoreState();
    return false;
  }
  
  /// parseDirectiveCFISameValue
  /// ::= .cfi_same_value register
  bool AsmParser::parseDirectiveCFISameValue(SMLoc DirectiveLoc) {
    int64_t Register = 0;
  
    if (parseRegisterOrRegisterNumber(Register, DirectiveLoc))
      return true;
  
    getStreamer().EmitCFISameValue(Register);
    return false;
  }
  
  /// parseDirectiveCFIRestore
  /// ::= .cfi_restore register
  bool AsmParser::parseDirectiveCFIRestore(SMLoc DirectiveLoc) {
    int64_t Register = 0;
    if (parseRegisterOrRegisterNumber(Register, DirectiveLoc))
      return true;
  
    getStreamer().EmitCFIRestore(Register);
    return false;
  }
  
  /// parseDirectiveCFIEscape
  /// ::= .cfi_escape expression[,...]
  bool AsmParser::parseDirectiveCFIEscape() {
    std::string Values;
    int64_t CurrValue;
    if (parseAbsoluteExpression(CurrValue))
      return true;
  
    Values.push_back((uint8_t)CurrValue);
  
    while (getLexer().is(AsmToken::Comma)) {
      Lex();
  
      if (parseAbsoluteExpression(CurrValue))
        return true;
  
      Values.push_back((uint8_t)CurrValue);
    }
  
    getStreamer().EmitCFIEscape(Values);
    return false;
  }
  
  /// parseDirectiveCFISignalFrame
  /// ::= .cfi_signal_frame
  bool AsmParser::parseDirectiveCFISignalFrame() {
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return Error(getLexer().getLoc(),
                   "unexpected token in '.cfi_signal_frame'");
  
    getStreamer().EmitCFISignalFrame();
    return false;
  }
  
  /// parseDirectiveCFIUndefined
  /// ::= .cfi_undefined register
  bool AsmParser::parseDirectiveCFIUndefined(SMLoc DirectiveLoc) {
    int64_t Register = 0;
  
    if (parseRegisterOrRegisterNumber(Register, DirectiveLoc))
      return true;
  
    getStreamer().EmitCFIUndefined(Register);
    return false;
  }
  
  /// parseDirectiveMacrosOnOff
  /// ::= .macros_on
  /// ::= .macros_off
  bool AsmParser::parseDirectiveMacrosOnOff(StringRef Directive) {
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return Error(getLexer().getLoc(),
                   "unexpected token in '" + Directive + "' directive");
  
    setMacrosEnabled(Directive == ".macros_on");
    return false;
  }
  
  /// parseDirectiveMacro
  /// ::= .macro name[,] [parameters]
  bool AsmParser::parseDirectiveMacro(SMLoc DirectiveLoc) {
    StringRef Name;
    if (parseIdentifier(Name))
      return TokError("expected identifier in '.macro' directive");
  
    if (getLexer().is(AsmToken::Comma))
      Lex();
  
    MCAsmMacroParameters Parameters;
    while (getLexer().isNot(AsmToken::EndOfStatement)) {
  
      if (!Parameters.empty() && Parameters.back().Vararg)
        return Error(Lexer.getLoc(),
                     "Vararg parameter '" + Parameters.back().Name +
                     "' should be last one in the list of parameters.");
  
      MCAsmMacroParameter Parameter;
      if (parseIdentifier(Parameter.Name))
        return TokError("expected identifier in '.macro' directive");
  
      if (Lexer.is(AsmToken::Colon)) {
        Lex();  // consume ':'
  
        SMLoc QualLoc;
        StringRef Qualifier;
  
        QualLoc = Lexer.getLoc();
        if (parseIdentifier(Qualifier))
          return Error(QualLoc, "missing parameter qualifier for "
                       "'" + Parameter.Name + "' in macro '" + Name + "'");
  
        if (Qualifier == "req")
          Parameter.Required = true;
        else if (Qualifier == "vararg")
          Parameter.Vararg = true;
        else
          return Error(QualLoc, Qualifier + " is not a valid parameter qualifier "
                       "for '" + Parameter.Name + "' in macro '" + Name + "'");
      }
  
      if (getLexer().is(AsmToken::Equal)) {
        Lex();
  
        SMLoc ParamLoc;
  
        ParamLoc = Lexer.getLoc();
        if (parseMacroArgument(Parameter.Value, /*Vararg=*/false ))
          return true;
  
        if (Parameter.Required)
          Warning(ParamLoc, "pointless default value for required parameter "
                  "'" + Parameter.Name + "' in macro '" + Name + "'");
      }
  
      Parameters.push_back(std::move(Parameter));
  
      if (getLexer().is(AsmToken::Comma))
        Lex();
    }
  
    // Eat the end of statement.
    Lex();
  
    AsmToken EndToken, StartToken = getTok();
    unsigned MacroDepth = 0;
  
    // Lex the macro definition.
    for (;;) {
      // Check whether we have reached the end of the file.
      if (getLexer().is(AsmToken::Eof))
        return Error(DirectiveLoc, "no matching '.endmacro' in definition");
  
      // Otherwise, check whether we have reach the .endmacro.
      if (getLexer().is(AsmToken::Identifier)) {
        if (getTok().getIdentifier() == ".endm" ||
            getTok().getIdentifier() == ".endmacro") {
          if (MacroDepth == 0) { // Outermost macro.
            EndToken = getTok();
            Lex();
            if (getLexer().isNot(AsmToken::EndOfStatement))
              return TokError("unexpected token in '" + EndToken.getIdentifier() +
                              "' directive");
            break;
          } else {
            // Otherwise we just found the end of an inner macro.
            --MacroDepth;
          }
        } else if (getTok().getIdentifier() == ".macro") {
          // We allow nested macros. Those aren't instantiated until the outermost
          // macro is expanded so just ignore them for now.
          ++MacroDepth;
        }
      }
  
      // Otherwise, scan til the end of the statement.
      eatToEndOfStatement();
    }
  
    if (lookupMacro(Name)) {
      return Error(DirectiveLoc, "macro '" + Name + "' is already defined");
    }
  
    const char *BodyStart = StartToken.getLoc().getPointer();
    const char *BodyEnd = EndToken.getLoc().getPointer();
    StringRef Body = StringRef(BodyStart, BodyEnd - BodyStart);
    checkForBadMacro(DirectiveLoc, Name, Body, Parameters);
    defineMacro(Name, MCAsmMacro(Name, Body, std::move(Parameters)));
    return false;
  }
  
  /// checkForBadMacro
  ///
  /// With the support added for named parameters there may be code out there that
  /// is transitioning from positional parameters.  In versions of gas that did
  /// not support named parameters they would be ignored on the macro definition.
  /// But to support both styles of parameters this is not possible so if a macro
  /// definition has named parameters but does not use them and has what appears
  /// to be positional parameters, strings like $1, $2, ... and $n, then issue a
  /// warning that the positional parameter found in body which have no effect.
  /// Hoping the developer will either remove the named parameters from the macro
  /// definition so the positional parameters get used if that was what was
  /// intended or change the macro to use the named parameters.  It is possible
  /// this warning will trigger when the none of the named parameters are used
  /// and the strings like $1 are infact to simply to be passed trough unchanged.
  void AsmParser::checkForBadMacro(SMLoc DirectiveLoc, StringRef Name,
                                   StringRef Body,
                                   ArrayRef<MCAsmMacroParameter> Parameters) {
    // If this macro is not defined with named parameters the warning we are
    // checking for here doesn't apply.
    unsigned NParameters = Parameters.size();
    if (NParameters == 0)
      return;
  
    bool NamedParametersFound = false;
    bool PositionalParametersFound = false;
  
    // Look at the body of the macro for use of both the named parameters and what
    // are likely to be positional parameters.  This is what expandMacro() is
    // doing when it finds the parameters in the body.
    while (!Body.empty()) {
      // Scan for the next possible parameter.
      std::size_t End = Body.size(), Pos = 0;
      for (; Pos != End; ++Pos) {
        // Check for a substitution or escape.
        // This macro is defined with parameters, look for \foo, \bar, etc.
        if (Body[Pos] == '\\' && Pos + 1 != End)
          break;
  
        // This macro should have parameters, but look for $0, $1, ..., $n too.
        if (Body[Pos] != '$' || Pos + 1 == End)
          continue;
        char Next = Body[Pos + 1];
        if (Next == '$' || Next == 'n' ||
            isdigit(static_cast<unsigned char>(Next)))
          break;
      }
  
      // Check if we reached the end.
      if (Pos == End)
        break;
  
      if (Body[Pos] == '$') {
        switch (Body[Pos + 1]) {
        // $$ => $
        case '$':
          break;
  
        // $n => number of arguments
        case 'n':
          PositionalParametersFound = true;
          break;
  
        // $[0-9] => argument
        default: {
          PositionalParametersFound = true;
          break;
        }
        }
        Pos += 2;
      } else {
        unsigned I = Pos + 1;
        while (isIdentifierChar(Body[I]) && I + 1 != End)
          ++I;
  
        const char *Begin = Body.data() + Pos + 1;
        StringRef Argument(Begin, I - (Pos + 1));
        unsigned Index = 0;
        for (; Index < NParameters; ++Index)
          if (Parameters[Index].Name == Argument)
            break;
  
        if (Index == NParameters) {
          if (Body[Pos + 1] == '(' && Body[Pos + 2] == ')')
            Pos += 3;
          else {
            Pos = I;
          }
        } else {
          NamedParametersFound = true;
          Pos += 1 + Argument.size();
        }
      }
      // Update the scan point.
      Body = Body.substr(Pos);
    }
  
    if (!NamedParametersFound && PositionalParametersFound)
      Warning(DirectiveLoc, "macro defined with named parameters which are not "
                            "used in macro body, possible positional parameter "
                            "found in body which will have no effect");
  }
  
  /// parseDirectiveExitMacro
  /// ::= .exitm
  bool AsmParser::parseDirectiveExitMacro(StringRef Directive) {
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '" + Directive + "' directive");
  
    if (!isInsideMacroInstantiation())
      return TokError("unexpected '" + Directive + "' in file, "
                                                   "no current macro definition");
  
    // Exit all conditionals that are active in the current macro.
    while (TheCondStack.size() != ActiveMacros.back()->CondStackDepth) {
      TheCondState = TheCondStack.back();
      TheCondStack.pop_back();
    }
  
    handleMacroExit();
    return false;
  }
  
  /// parseDirectiveEndMacro
  /// ::= .endm
  /// ::= .endmacro
  bool AsmParser::parseDirectiveEndMacro(StringRef Directive) {
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '" + Directive + "' directive");
  
    // If we are inside a macro instantiation, terminate the current
    // instantiation.
    if (isInsideMacroInstantiation()) {
      handleMacroExit();
      return false;
    }
  
    // Otherwise, this .endmacro is a stray entry in the file; well formed
    // .endmacro directives are handled during the macro definition parsing.
    return TokError("unexpected '" + Directive + "' in file, "
                                                 "no current macro definition");
  }
  
  /// parseDirectivePurgeMacro
  /// ::= .purgem
  bool AsmParser::parseDirectivePurgeMacro(SMLoc DirectiveLoc) {
    StringRef Name;
    if (parseIdentifier(Name))
      return TokError("expected identifier in '.purgem' directive");
  
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.purgem' directive");
  
    if (!lookupMacro(Name))
      return Error(DirectiveLoc, "macro '" + Name + "' is not defined");
  
    undefineMacro(Name);
    return false;
  }
  
  /// parseDirectiveBundleAlignMode
  /// ::= {.bundle_align_mode} expression
  bool AsmParser::parseDirectiveBundleAlignMode() {
    checkForValidSection();
  
    // Expect a single argument: an expression that evaluates to a constant
    // in the inclusive range 0-30.
    SMLoc ExprLoc = getLexer().getLoc();
    int64_t AlignSizePow2;
    if (parseAbsoluteExpression(AlignSizePow2))
      return true;
    else if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token after expression in"
                      " '.bundle_align_mode' directive");
    else if (AlignSizePow2 < 0 || AlignSizePow2 > 30)
      return Error(ExprLoc,
                   "invalid bundle alignment size (expected between 0 and 30)");
  
    Lex();
  
    // Because of AlignSizePow2's verified range we can safely truncate it to
    // unsigned.
    getStreamer().EmitBundleAlignMode(static_cast<unsigned>(AlignSizePow2));
    return false;
  }
  
  /// parseDirectiveBundleLock
  /// ::= {.bundle_lock} [align_to_end]
  bool AsmParser::parseDirectiveBundleLock() {
    checkForValidSection();
    bool AlignToEnd = false;
  
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      StringRef Option;
      SMLoc Loc = getTok().getLoc();
      const char *kInvalidOptionError =
          "invalid option for '.bundle_lock' directive";
  
      if (parseIdentifier(Option))
        return Error(Loc, kInvalidOptionError);
  
      if (Option != "align_to_end")
        return Error(Loc, kInvalidOptionError);
      else if (getLexer().isNot(AsmToken::EndOfStatement))
        return Error(Loc,
                     "unexpected token after '.bundle_lock' directive option");
      AlignToEnd = true;
    }
  
    Lex();
  
    getStreamer().EmitBundleLock(AlignToEnd);
    return false;
  }
  
  /// parseDirectiveBundleLock
  /// ::= {.bundle_lock}
  bool AsmParser::parseDirectiveBundleUnlock() {
    checkForValidSection();
  
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.bundle_unlock' directive");
    Lex();
  
    getStreamer().EmitBundleUnlock();
    return false;
  }
  
  /// parseDirectiveSpace
  /// ::= (.skip | .space) expression [ , expression ]
  bool AsmParser::parseDirectiveSpace(StringRef IDVal) {
    checkForValidSection();
  
    int64_t NumBytes;
    if (parseAbsoluteExpression(NumBytes))
      return true;
  
    int64_t FillExpr = 0;
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      if (getLexer().isNot(AsmToken::Comma))
        return TokError("unexpected token in '" + Twine(IDVal) + "' directive");
      Lex();
  
      if (parseAbsoluteExpression(FillExpr))
        return true;
  
      if (getLexer().isNot(AsmToken::EndOfStatement))
        return TokError("unexpected token in '" + Twine(IDVal) + "' directive");
    }
  
    Lex();
  
    if (NumBytes <= 0)
      return TokError("invalid number of bytes in '" + Twine(IDVal) +
                      "' directive");
  
    // FIXME: Sometimes the fill expr is 'nop' if it isn't supplied, instead of 0.
    getStreamer().EmitFill(NumBytes, FillExpr);
  
    return false;
  }
  
  /// parseDirectiveLEB128
  /// ::= (.sleb128 | .uleb128) [ expression (, expression)* ]
  bool AsmParser::parseDirectiveLEB128(bool Signed) {
    checkForValidSection();
    const MCExpr *Value;
  
    for (;;) {
      if (parseExpression(Value))
        return true;
  
      if (Signed)
        getStreamer().EmitSLEB128Value(Value);
      else
        getStreamer().EmitULEB128Value(Value);
  
      if (getLexer().is(AsmToken::EndOfStatement))
        break;
  
      if (getLexer().isNot(AsmToken::Comma))
        return TokError("unexpected token in directive");
      Lex();
    }
  
    return false;
  }
  
  /// parseDirectiveSymbolAttribute
  ///  ::= { ".globl", ".weak", ... } [ identifier ( , identifier )* ]
  bool AsmParser::parseDirectiveSymbolAttribute(MCSymbolAttr Attr) {
    if (getLexer().isNot(AsmToken::EndOfStatement)) {
      for (;;) {
        StringRef Name;
        SMLoc Loc = getTok().getLoc();
  
        if (parseIdentifier(Name))
          return Error(Loc, "expected identifier in directive");
  
        MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
  
        // Assembler local symbols don't make any sense here. Complain loudly.
        if (Sym->isTemporary())
          return Error(Loc, "non-local symbol required in directive");
  
        if (!getStreamer().EmitSymbolAttribute(Sym, Attr))
          return Error(Loc, "unable to emit symbol attribute");
  
        if (getLexer().is(AsmToken::EndOfStatement))
          break;
  
        if (getLexer().isNot(AsmToken::Comma))
          return TokError("unexpected token in directive");
        Lex();
      }
    }
  
    Lex();
    return false;
  }
  
  /// parseDirectiveComm
  ///  ::= ( .comm | .lcomm ) identifier , size_expression [ , align_expression ]
  bool AsmParser::parseDirectiveComm(bool IsLocal) {
    checkForValidSection();
  
    SMLoc IDLoc = getLexer().getLoc();
    StringRef Name;
    if (parseIdentifier(Name))
      return TokError("expected identifier in directive");
  
    // Handle the identifier as the key symbol.
    MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
  
    if (getLexer().isNot(AsmToken::Comma))
      return TokError("unexpected token in directive");
    Lex();
  
    int64_t Size;
    SMLoc SizeLoc = getLexer().getLoc();
    if (parseAbsoluteExpression(Size))
      return true;
  
    int64_t Pow2Alignment = 0;
    SMLoc Pow2AlignmentLoc;
    if (getLexer().is(AsmToken::Comma)) {
      Lex();
      Pow2AlignmentLoc = getLexer().getLoc();
      if (parseAbsoluteExpression(Pow2Alignment))
        return true;
  
      LCOMM::LCOMMType LCOMM = Lexer.getMAI().getLCOMMDirectiveAlignmentType();
      if (IsLocal && LCOMM == LCOMM::NoAlignment)
        return Error(Pow2AlignmentLoc, "alignment not supported on this target");
  
      // If this target takes alignments in bytes (not log) validate and convert.
      if ((!IsLocal && Lexer.getMAI().getCOMMDirectiveAlignmentIsInBytes()) ||
          (IsLocal && LCOMM == LCOMM::ByteAlignment)) {
        if (!isPowerOf2_64(Pow2Alignment))
          return Error(Pow2AlignmentLoc, "alignment must be a power of 2");
        Pow2Alignment = Log2_64(Pow2Alignment);
      }
    }
  
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.comm' or '.lcomm' directive");
  
    Lex();
  
    // NOTE: a size of zero for a .comm should create a undefined symbol
    // but a size of .lcomm creates a bss symbol of size zero.
    if (Size < 0)
      return Error(SizeLoc, "invalid '.comm' or '.lcomm' directive size, can't "
                            "be less than zero");
  
    // NOTE: The alignment in the directive is a power of 2 value, the assembler
    // may internally end up wanting an alignment in bytes.
    // FIXME: Diagnose overflow.
    if (Pow2Alignment < 0)
      return Error(Pow2AlignmentLoc, "invalid '.comm' or '.lcomm' directive "
                                     "alignment, can't be less than zero");
  
    if (!Sym->isUndefined())
      return Error(IDLoc, "invalid symbol redefinition");
  
    // Create the Symbol as a common or local common with Size and Pow2Alignment
    if (IsLocal) {
      getStreamer().EmitLocalCommonSymbol(Sym, Size, 1 << Pow2Alignment);
      return false;
    }
  
    getStreamer().EmitCommonSymbol(Sym, Size, 1 << Pow2Alignment);
    return false;
  }
  
  /// parseDirectiveAbort
  ///  ::= .abort [... message ...]
  bool AsmParser::parseDirectiveAbort() {
    // FIXME: Use loc from directive.
    SMLoc Loc = getLexer().getLoc();
  
    StringRef Str = parseStringToEndOfStatement();
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.abort' directive");
  
    Lex();
  
    if (Str.empty())
      Error(Loc, ".abort detected. Assembly stopping.");
    else
      Error(Loc, ".abort '" + Str + "' detected. Assembly stopping.");
    // FIXME: Actually abort assembly here.
  
    return false;
  }
  
  /// parseDirectiveInclude
  ///  ::= .include "filename"
  bool AsmParser::parseDirectiveInclude() {
    if (getLexer().isNot(AsmToken::String))
      return TokError("expected string in '.include' directive");
  
    // Allow the strings to have escaped octal character sequence.
    std::string Filename;
    if (parseEscapedString(Filename))
      return true;
    SMLoc IncludeLoc = getLexer().getLoc();
    Lex();
  
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.include' directive");
  
    // Attempt to switch the lexer to the included file before consuming the end
    // of statement to avoid losing it when we switch.
    if (enterIncludeFile(Filename)) {
      Error(IncludeLoc, "Could not find include file '" + Filename + "'");
      return true;
    }
  
    return false;
  }
  
  /// parseDirectiveIncbin
  ///  ::= .incbin "filename"
  bool AsmParser::parseDirectiveIncbin() {
    if (getLexer().isNot(AsmToken::String))
      return TokError("expected string in '.incbin' directive");
  
    // Allow the strings to have escaped octal character sequence.
    std::string Filename;
    if (parseEscapedString(Filename))
      return true;
    SMLoc IncbinLoc = getLexer().getLoc();
    Lex();
  
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.incbin' directive");
  
    // Attempt to process the included file.
    if (processIncbinFile(Filename)) {
      Error(IncbinLoc, "Could not find incbin file '" + Filename + "'");
      return true;
    }
  
    return false;
  }
  
  /// parseDirectiveIf
  /// ::= .if{,eq,ge,gt,le,lt,ne} expression
  bool AsmParser::parseDirectiveIf(SMLoc DirectiveLoc, DirectiveKind DirKind) {
    TheCondStack.push_back(TheCondState);
    TheCondState.TheCond = AsmCond::IfCond;
    if (TheCondState.Ignore) {
      eatToEndOfStatement();
    } else {
      int64_t ExprValue;
      if (parseAbsoluteExpression(ExprValue))
        return true;
  
      if (getLexer().isNot(AsmToken::EndOfStatement))
        return TokError("unexpected token in '.if' directive");
  
      Lex();
  
      switch (DirKind) {
      default:
        llvm_unreachable("unsupported directive");
      case DK_IF:
      case DK_IFNE:
        break;
      case DK_IFEQ:
        ExprValue = ExprValue == 0;
        break;
      case DK_IFGE:
        ExprValue = ExprValue >= 0;
        break;
      case DK_IFGT:
        ExprValue = ExprValue > 0;
        break;
      case DK_IFLE:
        ExprValue = ExprValue <= 0;
        break;
      case DK_IFLT:
        ExprValue = ExprValue < 0;
        break;
      }
  
      TheCondState.CondMet = ExprValue;
      TheCondState.Ignore = !TheCondState.CondMet;
    }
  
    return false;
  }
  
  /// parseDirectiveIfb
  /// ::= .ifb string
  bool AsmParser::parseDirectiveIfb(SMLoc DirectiveLoc, bool ExpectBlank) {
    TheCondStack.push_back(TheCondState);
    TheCondState.TheCond = AsmCond::IfCond;
  
    if (TheCondState.Ignore) {
      eatToEndOfStatement();
    } else {
      StringRef Str = parseStringToEndOfStatement();
  
      if (getLexer().isNot(AsmToken::EndOfStatement))
        return TokError("unexpected token in '.ifb' directive");
  
      Lex();
  
      TheCondState.CondMet = ExpectBlank == Str.empty();
      TheCondState.Ignore = !TheCondState.CondMet;
    }
  
    return false;
  }
  
  /// parseDirectiveIfc
  /// ::= .ifc string1, string2
  /// ::= .ifnc string1, string2
  bool AsmParser::parseDirectiveIfc(SMLoc DirectiveLoc, bool ExpectEqual) {
    TheCondStack.push_back(TheCondState);
    TheCondState.TheCond = AsmCond::IfCond;
  
    if (TheCondState.Ignore) {
      eatToEndOfStatement();
    } else {
      StringRef Str1 = parseStringToComma();
  
      if (getLexer().isNot(AsmToken::Comma))
        return TokError("unexpected token in '.ifc' directive");
  
      Lex();
  
      StringRef Str2 = parseStringToEndOfStatement();
  
      if (getLexer().isNot(AsmToken::EndOfStatement))
        return TokError("unexpected token in '.ifc' directive");
  
      Lex();
  
      TheCondState.CondMet = ExpectEqual == (Str1.trim() == Str2.trim());
      TheCondState.Ignore = !TheCondState.CondMet;
    }
  
    return false;
  }
  
  /// parseDirectiveIfeqs
  ///   ::= .ifeqs string1, string2
  bool AsmParser::parseDirectiveIfeqs(SMLoc DirectiveLoc, bool ExpectEqual) {
    if (Lexer.isNot(AsmToken::String)) {
      if (ExpectEqual)
        TokError("expected string parameter for '.ifeqs' directive");
      else
        TokError("expected string parameter for '.ifnes' directive");
      eatToEndOfStatement();
      return true;
    }
  
    StringRef String1 = getTok().getStringContents();
    Lex();
  
    if (Lexer.isNot(AsmToken::Comma)) {
      if (ExpectEqual)
        TokError("expected comma after first string for '.ifeqs' directive");
      else
        TokError("expected comma after first string for '.ifnes' directive");
      eatToEndOfStatement();
      return true;
    }
  
    Lex();
  
    if (Lexer.isNot(AsmToken::String)) {
      if (ExpectEqual)
        TokError("expected string parameter for '.ifeqs' directive");
      else
        TokError("expected string parameter for '.ifnes' directive");
      eatToEndOfStatement();
      return true;
    }
  
    StringRef String2 = getTok().getStringContents();
    Lex();
  
    TheCondStack.push_back(TheCondState);
    TheCondState.TheCond = AsmCond::IfCond;
    TheCondState.CondMet = ExpectEqual == (String1 == String2);
    TheCondState.Ignore = !TheCondState.CondMet;
  
    return false;
  }
  
  /// parseDirectiveIfdef
  /// ::= .ifdef symbol
  bool AsmParser::parseDirectiveIfdef(SMLoc DirectiveLoc, bool expect_defined) {
    StringRef Name;
    TheCondStack.push_back(TheCondState);
    TheCondState.TheCond = AsmCond::IfCond;
  
    if (TheCondState.Ignore) {
      eatToEndOfStatement();
    } else {
      if (parseIdentifier(Name))
        return TokError("expected identifier after '.ifdef'");
  
      Lex();
  
      MCSymbol *Sym = getContext().lookupSymbol(Name);
  
      if (expect_defined)
        TheCondState.CondMet = (Sym && !Sym->isUndefined());
      else
        TheCondState.CondMet = (!Sym || Sym->isUndefined());
      TheCondState.Ignore = !TheCondState.CondMet;
    }
  
    return false;
  }
  
  /// parseDirectiveElseIf
  /// ::= .elseif expression
  bool AsmParser::parseDirectiveElseIf(SMLoc DirectiveLoc) {
    if (TheCondState.TheCond != AsmCond::IfCond &&
        TheCondState.TheCond != AsmCond::ElseIfCond)
      Error(DirectiveLoc, "Encountered a .elseif that doesn't follow a .if or "
                          " an .elseif");
    TheCondState.TheCond = AsmCond::ElseIfCond;
  
    bool LastIgnoreState = false;
    if (!TheCondStack.empty())
      LastIgnoreState = TheCondStack.back().Ignore;
    if (LastIgnoreState || TheCondState.CondMet) {
      TheCondState.Ignore = true;
      eatToEndOfStatement();
    } else {
      int64_t ExprValue;
      if (parseAbsoluteExpression(ExprValue))
        return true;
  
      if (getLexer().isNot(AsmToken::EndOfStatement))
        return TokError("unexpected token in '.elseif' directive");
  
      Lex();
      TheCondState.CondMet = ExprValue;
      TheCondState.Ignore = !TheCondState.CondMet;
    }
  
    return false;
  }
  
  /// parseDirectiveElse
  /// ::= .else
  bool AsmParser::parseDirectiveElse(SMLoc DirectiveLoc) {
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.else' directive");
  
    Lex();
  
    if (TheCondState.TheCond != AsmCond::IfCond &&
        TheCondState.TheCond != AsmCond::ElseIfCond)
      Error(DirectiveLoc, "Encountered a .else that doesn't follow a .if or an "
                          ".elseif");
    TheCondState.TheCond = AsmCond::ElseCond;
    bool LastIgnoreState = false;
    if (!TheCondStack.empty())
      LastIgnoreState = TheCondStack.back().Ignore;
    if (LastIgnoreState || TheCondState.CondMet)
      TheCondState.Ignore = true;
    else
      TheCondState.Ignore = false;
  
    return false;
  }
  
  /// parseDirectiveEnd
  /// ::= .end
  bool AsmParser::parseDirectiveEnd(SMLoc DirectiveLoc) {
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.end' directive");
  
    Lex();
  
    while (Lexer.isNot(AsmToken::Eof))
      Lex();
  
    return false;
  }
  
  /// parseDirectiveError
  ///   ::= .err
  ///   ::= .error [string]
  bool AsmParser::parseDirectiveError(SMLoc L, bool WithMessage) {
    if (!TheCondStack.empty()) {
      if (TheCondStack.back().Ignore) {
        eatToEndOfStatement();
        return false;
      }
    }
  
    if (!WithMessage)
      return Error(L, ".err encountered");
  
    StringRef Message = ".error directive invoked in source file";
    if (Lexer.isNot(AsmToken::EndOfStatement)) {
      if (Lexer.isNot(AsmToken::String)) {
        TokError(".error argument must be a string");
        eatToEndOfStatement();
        return true;
      }
  
      Message = getTok().getStringContents();
      Lex();
    }
  
    Error(L, Message);
    return true;
  }
  
  /// parseDirectiveWarning
  ///   ::= .warning [string]
  bool AsmParser::parseDirectiveWarning(SMLoc L) {
    if (!TheCondStack.empty()) {
      if (TheCondStack.back().Ignore) {
        eatToEndOfStatement();
        return false;
      }
    }
  
    StringRef Message = ".warning directive invoked in source file";
    if (Lexer.isNot(AsmToken::EndOfStatement)) {
      if (Lexer.isNot(AsmToken::String)) {
        TokError(".warning argument must be a string");
        eatToEndOfStatement();
        return true;
      }
  
      Message = getTok().getStringContents();
      Lex();
    }
  
    Warning(L, Message);
    return false;
  }
  
  /// parseDirectiveEndIf
  /// ::= .endif
  bool AsmParser::parseDirectiveEndIf(SMLoc DirectiveLoc) {
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '.endif' directive");
  
    Lex();
  
    if ((TheCondState.TheCond == AsmCond::NoCond) || TheCondStack.empty())
      Error(DirectiveLoc, "Encountered a .endif that doesn't follow a .if or "
                          ".else");
    if (!TheCondStack.empty()) {
      TheCondState = TheCondStack.back();
      TheCondStack.pop_back();
    }
  
    return false;
  }
  
  void AsmParser::initializeDirectiveKindMap() {
    DirectiveKindMap[".set"] = DK_SET;
    DirectiveKindMap[".equ"] = DK_EQU;
    DirectiveKindMap[".equiv"] = DK_EQUIV;
    DirectiveKindMap[".ascii"] = DK_ASCII;
    DirectiveKindMap[".asciz"] = DK_ASCIZ;
    DirectiveKindMap[".string"] = DK_STRING;
    DirectiveKindMap[".byte"] = DK_BYTE;
    DirectiveKindMap[".short"] = DK_SHORT;
    DirectiveKindMap[".value"] = DK_VALUE;
    DirectiveKindMap[".2byte"] = DK_2BYTE;
    DirectiveKindMap[".long"] = DK_LONG;
    DirectiveKindMap[".int"] = DK_INT;
    DirectiveKindMap[".4byte"] = DK_4BYTE;
    DirectiveKindMap[".quad"] = DK_QUAD;
    DirectiveKindMap[".8byte"] = DK_8BYTE;
    DirectiveKindMap[".octa"] = DK_OCTA;
    DirectiveKindMap[".single"] = DK_SINGLE;
    DirectiveKindMap[".float"] = DK_FLOAT;
    DirectiveKindMap[".double"] = DK_DOUBLE;
    DirectiveKindMap[".align"] = DK_ALIGN;
    DirectiveKindMap[".align32"] = DK_ALIGN32;
    DirectiveKindMap[".balign"] = DK_BALIGN;
    DirectiveKindMap[".balignw"] = DK_BALIGNW;
    DirectiveKindMap[".balignl"] = DK_BALIGNL;
    DirectiveKindMap[".p2align"] = DK_P2ALIGN;
    DirectiveKindMap[".p2alignw"] = DK_P2ALIGNW;
    DirectiveKindMap[".p2alignl"] = DK_P2ALIGNL;
    DirectiveKindMap[".org"] = DK_ORG;
    DirectiveKindMap[".fill"] = DK_FILL;
    DirectiveKindMap[".zero"] = DK_ZERO;
    DirectiveKindMap[".extern"] = DK_EXTERN;
    DirectiveKindMap[".globl"] = DK_GLOBL;
    DirectiveKindMap[".global"] = DK_GLOBAL;
    DirectiveKindMap[".lazy_reference"] = DK_LAZY_REFERENCE;
    DirectiveKindMap[".no_dead_strip"] = DK_NO_DEAD_STRIP;
    DirectiveKindMap[".symbol_resolver"] = DK_SYMBOL_RESOLVER;
    DirectiveKindMap[".private_extern"] = DK_PRIVATE_EXTERN;
    DirectiveKindMap[".reference"] = DK_REFERENCE;
    DirectiveKindMap[".weak_definition"] = DK_WEAK_DEFINITION;
    DirectiveKindMap[".weak_reference"] = DK_WEAK_REFERENCE;
    DirectiveKindMap[".weak_def_can_be_hidden"] = DK_WEAK_DEF_CAN_BE_HIDDEN;
    DirectiveKindMap[".comm"] = DK_COMM;
    DirectiveKindMap[".common"] = DK_COMMON;
    DirectiveKindMap[".lcomm"] = DK_LCOMM;
    DirectiveKindMap[".abort"] = DK_ABORT;
    DirectiveKindMap[".include"] = DK_INCLUDE;
    DirectiveKindMap[".incbin"] = DK_INCBIN;
    DirectiveKindMap[".code16"] = DK_CODE16;
    DirectiveKindMap[".code16gcc"] = DK_CODE16GCC;
    DirectiveKindMap[".rept"] = DK_REPT;
    DirectiveKindMap[".rep"] = DK_REPT;
    DirectiveKindMap[".irp"] = DK_IRP;
    DirectiveKindMap[".irpc"] = DK_IRPC;
    DirectiveKindMap[".endr"] = DK_ENDR;
    DirectiveKindMap[".bundle_align_mode"] = DK_BUNDLE_ALIGN_MODE;
    DirectiveKindMap[".bundle_lock"] = DK_BUNDLE_LOCK;
    DirectiveKindMap[".bundle_unlock"] = DK_BUNDLE_UNLOCK;
    DirectiveKindMap[".if"] = DK_IF;
    DirectiveKindMap[".ifeq"] = DK_IFEQ;
    DirectiveKindMap[".ifge"] = DK_IFGE;
    DirectiveKindMap[".ifgt"] = DK_IFGT;
    DirectiveKindMap[".ifle"] = DK_IFLE;
    DirectiveKindMap[".iflt"] = DK_IFLT;
    DirectiveKindMap[".ifne"] = DK_IFNE;
    DirectiveKindMap[".ifb"] = DK_IFB;
    DirectiveKindMap[".ifnb"] = DK_IFNB;
    DirectiveKindMap[".ifc"] = DK_IFC;
    DirectiveKindMap[".ifeqs"] = DK_IFEQS;
    DirectiveKindMap[".ifnc"] = DK_IFNC;
    DirectiveKindMap[".ifnes"] = DK_IFNES;
    DirectiveKindMap[".ifdef"] = DK_IFDEF;
    DirectiveKindMap[".ifndef"] = DK_IFNDEF;
    DirectiveKindMap[".ifnotdef"] = DK_IFNOTDEF;
    DirectiveKindMap[".elseif"] = DK_ELSEIF;
    DirectiveKindMap[".else"] = DK_ELSE;
    DirectiveKindMap[".end"] = DK_END;
    DirectiveKindMap[".endif"] = DK_ENDIF;
    DirectiveKindMap[".skip"] = DK_SKIP;
    DirectiveKindMap[".space"] = DK_SPACE;
    DirectiveKindMap[".file"] = DK_FILE;
    DirectiveKindMap[".line"] = DK_LINE;
    DirectiveKindMap[".loc"] = DK_LOC;
    DirectiveKindMap[".stabs"] = DK_STABS;
    DirectiveKindMap[".cv_file"] = DK_CV_FILE;
    DirectiveKindMap[".cv_loc"] = DK_CV_LOC;
    DirectiveKindMap[".cv_linetable"] = DK_CV_LINETABLE;
    DirectiveKindMap[".cv_inline_linetable"] = DK_CV_INLINE_LINETABLE;
    DirectiveKindMap[".cv_stringtable"] = DK_CV_STRINGTABLE;
    DirectiveKindMap[".cv_filechecksums"] = DK_CV_FILECHECKSUMS;
    DirectiveKindMap[".sleb128"] = DK_SLEB128;
    DirectiveKindMap[".uleb128"] = DK_ULEB128;
    DirectiveKindMap[".cfi_sections"] = DK_CFI_SECTIONS;
    DirectiveKindMap[".cfi_startproc"] = DK_CFI_STARTPROC;
    DirectiveKindMap[".cfi_endproc"] = DK_CFI_ENDPROC;
    DirectiveKindMap[".cfi_def_cfa"] = DK_CFI_DEF_CFA;
    DirectiveKindMap[".cfi_def_cfa_offset"] = DK_CFI_DEF_CFA_OFFSET;
    DirectiveKindMap[".cfi_adjust_cfa_offset"] = DK_CFI_ADJUST_CFA_OFFSET;
    DirectiveKindMap[".cfi_def_cfa_register"] = DK_CFI_DEF_CFA_REGISTER;
    DirectiveKindMap[".cfi_offset"] = DK_CFI_OFFSET;
    DirectiveKindMap[".cfi_rel_offset"] = DK_CFI_REL_OFFSET;
    DirectiveKindMap[".cfi_personality"] = DK_CFI_PERSONALITY;
    DirectiveKindMap[".cfi_lsda"] = DK_CFI_LSDA;
    DirectiveKindMap[".cfi_remember_state"] = DK_CFI_REMEMBER_STATE;
    DirectiveKindMap[".cfi_restore_state"] = DK_CFI_RESTORE_STATE;
    DirectiveKindMap[".cfi_same_value"] = DK_CFI_SAME_VALUE;
    DirectiveKindMap[".cfi_restore"] = DK_CFI_RESTORE;
    DirectiveKindMap[".cfi_escape"] = DK_CFI_ESCAPE;
    DirectiveKindMap[".cfi_signal_frame"] = DK_CFI_SIGNAL_FRAME;
    DirectiveKindMap[".cfi_undefined"] = DK_CFI_UNDEFINED;
    DirectiveKindMap[".cfi_register"] = DK_CFI_REGISTER;
    DirectiveKindMap[".cfi_window_save"] = DK_CFI_WINDOW_SAVE;
    DirectiveKindMap[".macros_on"] = DK_MACROS_ON;
    DirectiveKindMap[".macros_off"] = DK_MACROS_OFF;
    DirectiveKindMap[".macro"] = DK_MACRO;
    DirectiveKindMap[".exitm"] = DK_EXITM;
    DirectiveKindMap[".endm"] = DK_ENDM;
    DirectiveKindMap[".endmacro"] = DK_ENDMACRO;
    DirectiveKindMap[".purgem"] = DK_PURGEM;
    DirectiveKindMap[".err"] = DK_ERR;
    DirectiveKindMap[".error"] = DK_ERROR;
    DirectiveKindMap[".warning"] = DK_WARNING;
    DirectiveKindMap[".reloc"] = DK_RELOC;
  }
  
  MCAsmMacro *AsmParser::parseMacroLikeBody(SMLoc DirectiveLoc) {
    AsmToken EndToken, StartToken = getTok();
  
    unsigned NestLevel = 0;
    for (;;) {
      // Check whether we have reached the end of the file.
      if (getLexer().is(AsmToken::Eof)) {
        Error(DirectiveLoc, "no matching '.endr' in definition");
        return nullptr;
      }
  
      if (Lexer.is(AsmToken::Identifier) &&
          (getTok().getIdentifier() == ".rept")) {
        ++NestLevel;
      }
  
      // Otherwise, check whether we have reached the .endr.
      if (Lexer.is(AsmToken::Identifier) && getTok().getIdentifier() == ".endr") {
        if (NestLevel == 0) {
          EndToken = getTok();
          Lex();
          if (Lexer.isNot(AsmToken::EndOfStatement)) {
            TokError("unexpected token in '.endr' directive");
            return nullptr;
          }
          break;
        }
        --NestLevel;
      }
  
      // Otherwise, scan till the end of the statement.
      eatToEndOfStatement();
    }
  
    const char *BodyStart = StartToken.getLoc().getPointer();
    const char *BodyEnd = EndToken.getLoc().getPointer();
    StringRef Body = StringRef(BodyStart, BodyEnd - BodyStart);
  
    // We Are Anonymous.
    MacroLikeBodies.emplace_back(StringRef(), Body, MCAsmMacroParameters());
    return &MacroLikeBodies.back();
  }
  
  void AsmParser::instantiateMacroLikeBody(MCAsmMacro *M, SMLoc DirectiveLoc,
                                           raw_svector_ostream &OS) {
    OS << ".endr\n";
  
    std::unique_ptr<MemoryBuffer> Instantiation =
        MemoryBuffer::getMemBufferCopy(OS.str(), "<instantiation>");
  
    // Create the macro instantiation object and add to the current macro
    // instantiation stack.
    MacroInstantiation *MI = new MacroInstantiation(
        DirectiveLoc, CurBuffer, getTok().getLoc(), TheCondStack.size());
    ActiveMacros.push_back(MI);
  
    // Jump to the macro instantiation and prime the lexer.
    CurBuffer = SrcMgr.AddNewSourceBuffer(std::move(Instantiation), SMLoc());
    Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer());
    Lex();
  }
  
  /// parseDirectiveRept
  ///   ::= .rep | .rept count
  bool AsmParser::parseDirectiveRept(SMLoc DirectiveLoc, StringRef Dir) {
    const MCExpr *CountExpr;
    SMLoc CountLoc = getTok().getLoc();
    if (parseExpression(CountExpr))
      return true;
  
    int64_t Count;
    if (!CountExpr->evaluateAsAbsolute(Count)) {
      eatToEndOfStatement();
      return Error(CountLoc, "unexpected token in '" + Dir + "' directive");
    }
  
    if (Count < 0)
      return Error(CountLoc, "Count is negative");
  
    if (Lexer.isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '" + Dir + "' directive");
  
    // Eat the end of statement.
    Lex();
  
    // Lex the rept definition.
    MCAsmMacro *M = parseMacroLikeBody(DirectiveLoc);
    if (!M)
      return true;
  
    // Macro instantiation is lexical, unfortunately. We construct a new buffer
    // to hold the macro body with substitutions.
    SmallString<256> Buf;
    raw_svector_ostream OS(Buf);
    while (Count--) {
      // Note that the AtPseudoVariable is disabled for instantiations of .rep(t).
      if (expandMacro(OS, M->Body, None, None, false, getTok().getLoc()))
        return true;
    }
    instantiateMacroLikeBody(M, DirectiveLoc, OS);
  
    return false;
  }
  
  /// parseDirectiveIrp
  /// ::= .irp symbol,values
  bool AsmParser::parseDirectiveIrp(SMLoc DirectiveLoc) {
    MCAsmMacroParameter Parameter;
  
    if (parseIdentifier(Parameter.Name))
      return TokError("expected identifier in '.irp' directive");
  
    if (Lexer.isNot(AsmToken::Comma))
      return TokError("expected comma in '.irp' directive");
  
    Lex();
  
    MCAsmMacroArguments A;
    if (parseMacroArguments(nullptr, A))
      return true;
  
    // Eat the end of statement.
    Lex();
  
    // Lex the irp definition.
    MCAsmMacro *M = parseMacroLikeBody(DirectiveLoc);
    if (!M)
      return true;
  
    // Macro instantiation is lexical, unfortunately. We construct a new buffer
    // to hold the macro body with substitutions.
    SmallString<256> Buf;
    raw_svector_ostream OS(Buf);
  
    for (const MCAsmMacroArgument &Arg : A) {
      // Note that the AtPseudoVariable is enabled for instantiations of .irp.
      // This is undocumented, but GAS seems to support it.
      if (expandMacro(OS, M->Body, Parameter, Arg, true, getTok().getLoc()))
        return true;
    }
  
    instantiateMacroLikeBody(M, DirectiveLoc, OS);
  
    return false;
  }
  
  /// parseDirectiveIrpc
  /// ::= .irpc symbol,values
  bool AsmParser::parseDirectiveIrpc(SMLoc DirectiveLoc) {
    MCAsmMacroParameter Parameter;
  
    if (parseIdentifier(Parameter.Name))
      return TokError("expected identifier in '.irpc' directive");
  
    if (Lexer.isNot(AsmToken::Comma))
      return TokError("expected comma in '.irpc' directive");
  
    Lex();
  
    MCAsmMacroArguments A;
    if (parseMacroArguments(nullptr, A))
      return true;
  
    if (A.size() != 1 || A.front().size() != 1)
      return TokError("unexpected token in '.irpc' directive");
  
    // Eat the end of statement.
    Lex();
  
    // Lex the irpc definition.
    MCAsmMacro *M = parseMacroLikeBody(DirectiveLoc);
    if (!M)
      return true;
  
    // Macro instantiation is lexical, unfortunately. We construct a new buffer
    // to hold the macro body with substitutions.
    SmallString<256> Buf;
    raw_svector_ostream OS(Buf);
  
    StringRef Values = A.front().front().getString();
    for (std::size_t I = 0, End = Values.size(); I != End; ++I) {
      MCAsmMacroArgument Arg;
      Arg.emplace_back(AsmToken::Identifier, Values.slice(I, I + 1));
  
      // Note that the AtPseudoVariable is enabled for instantiations of .irpc.
      // This is undocumented, but GAS seems to support it.
      if (expandMacro(OS, M->Body, Parameter, Arg, true, getTok().getLoc()))
        return true;
    }
  
    instantiateMacroLikeBody(M, DirectiveLoc, OS);
  
    return false;
  }
  
  bool AsmParser::parseDirectiveEndr(SMLoc DirectiveLoc) {
    if (ActiveMacros.empty())
      return TokError("unmatched '.endr' directive");
  
    // The only .repl that should get here are the ones created by
    // instantiateMacroLikeBody.
    assert(getLexer().is(AsmToken::EndOfStatement));
  
    handleMacroExit();
    return false;
  }
  
  bool AsmParser::parseDirectiveMSEmit(SMLoc IDLoc, ParseStatementInfo &Info,
                                       size_t Len) {
    const MCExpr *Value;
    SMLoc ExprLoc = getLexer().getLoc();
    if (parseExpression(Value))
      return true;
    const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(Value);
    if (!MCE)
      return Error(ExprLoc, "unexpected expression in _emit");
    uint64_t IntValue = MCE->getValue();
    if (!isUInt<8>(IntValue) && !isInt<8>(IntValue))
      return Error(ExprLoc, "literal value out of range for directive");
  
    Info.AsmRewrites->emplace_back(AOK_Emit, IDLoc, Len);
    return false;
  }
  
  bool AsmParser::parseDirectiveMSAlign(SMLoc IDLoc, ParseStatementInfo &Info) {
    const MCExpr *Value;
    SMLoc ExprLoc = getLexer().getLoc();
    if (parseExpression(Value))
      return true;
    const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(Value);
    if (!MCE)
      return Error(ExprLoc, "unexpected expression in align");
    uint64_t IntValue = MCE->getValue();
    if (!isPowerOf2_64(IntValue))
      return Error(ExprLoc, "literal value not a power of two greater then zero");
  
    Info.AsmRewrites->emplace_back(AOK_Align, IDLoc, 5, Log2_64(IntValue));
    return false;
  }
  
  // We are comparing pointers, but the pointers are relative to a single string.
  // Thus, this should always be deterministic.
  static int rewritesSort(const AsmRewrite *AsmRewriteA,
                          const AsmRewrite *AsmRewriteB) {
    if (AsmRewriteA->Loc.getPointer() < AsmRewriteB->Loc.getPointer())
      return -1;
    if (AsmRewriteB->Loc.getPointer() < AsmRewriteA->Loc.getPointer())
      return 1;
  
    // It's possible to have a SizeDirective, Imm/ImmPrefix and an Input/Output
    // rewrite to the same location.  Make sure the SizeDirective rewrite is
    // performed first, then the Imm/ImmPrefix and finally the Input/Output.  This
    // ensures the sort algorithm is stable.
    if (AsmRewritePrecedence[AsmRewriteA->Kind] >
        AsmRewritePrecedence[AsmRewriteB->Kind])
      return -1;
  
    if (AsmRewritePrecedence[AsmRewriteA->Kind] <
        AsmRewritePrecedence[AsmRewriteB->Kind])
      return 1;
    llvm_unreachable("Unstable rewrite sort.");
  }
  
  bool AsmParser::parseMSInlineAsm(
      void *AsmLoc, std::string &AsmString, unsigned &NumOutputs,
      unsigned &NumInputs, SmallVectorImpl<std::pair<void *, bool> > &OpDecls,
      SmallVectorImpl<std::string> &Constraints,
      SmallVectorImpl<std::string> &Clobbers, const MCInstrInfo *MII,
      const MCInstPrinter *IP, MCAsmParserSemaCallback &SI) {
    SmallVector<void *, 4> InputDecls;
    SmallVector<void *, 4> OutputDecls;
    SmallVector<bool, 4> InputDeclsAddressOf;
    SmallVector<bool, 4> OutputDeclsAddressOf;
    SmallVector<std::string, 4> InputConstraints;
    SmallVector<std::string, 4> OutputConstraints;
    SmallVector<unsigned, 4> ClobberRegs;
  
    SmallVector<AsmRewrite, 4> AsmStrRewrites;
  
    // Prime the lexer.
    Lex();
  
    // While we have input, parse each statement.
    unsigned InputIdx = 0;
    unsigned OutputIdx = 0;
    while (getLexer().isNot(AsmToken::Eof)) {
      ParseStatementInfo Info(&AsmStrRewrites);
      if (parseStatement(Info, &SI))
        return true;
  
      if (Info.ParseError)
        return true;
  
      if (Info.Opcode == ~0U)
        continue;
  
      const MCInstrDesc &Desc = MII->get(Info.Opcode);
  
      // Build the list of clobbers, outputs and inputs.
      for (unsigned i = 1, e = Info.ParsedOperands.size(); i != e; ++i) {
        MCParsedAsmOperand &Operand = *Info.ParsedOperands[i];
  
        // Immediate.
        if (Operand.isImm())
          continue;
  
        // Register operand.
        if (Operand.isReg() && !Operand.needAddressOf() &&
            !getTargetParser().OmitRegisterFromClobberLists(Operand.getReg())) {
          unsigned NumDefs = Desc.getNumDefs();
          // Clobber.
          if (NumDefs && Operand.getMCOperandNum() < NumDefs)
            ClobberRegs.push_back(Operand.getReg());
          continue;
        }
  
        // Expr/Input or Output.
        StringRef SymName = Operand.getSymName();
        if (SymName.empty())
          continue;
  
        void *OpDecl = Operand.getOpDecl();
        if (!OpDecl)
          continue;
  
        bool isOutput = (i == 1) && Desc.mayStore();
        SMLoc Start = SMLoc::getFromPointer(SymName.data());
        if (isOutput) {
          ++InputIdx;
          OutputDecls.push_back(OpDecl);
          OutputDeclsAddressOf.push_back(Operand.needAddressOf());
          OutputConstraints.push_back(("=" + Operand.getConstraint()).str());
          AsmStrRewrites.emplace_back(AOK_Output, Start, SymName.size());
        } else {
          InputDecls.push_back(OpDecl);
          InputDeclsAddressOf.push_back(Operand.needAddressOf());
          InputConstraints.push_back(Operand.getConstraint().str());
          AsmStrRewrites.emplace_back(AOK_Input, Start, SymName.size());
        }
      }
  
      // Consider implicit defs to be clobbers.  Think of cpuid and push.
      ArrayRef<MCPhysReg> ImpDefs(Desc.getImplicitDefs(),
                                  Desc.getNumImplicitDefs());
      ClobberRegs.insert(ClobberRegs.end(), ImpDefs.begin(), ImpDefs.end());
    }
  
    // Set the number of Outputs and Inputs.
    NumOutputs = OutputDecls.size();
    NumInputs = InputDecls.size();
  
    // Set the unique clobbers.
    array_pod_sort(ClobberRegs.begin(), ClobberRegs.end());
    ClobberRegs.erase(std::unique(ClobberRegs.begin(), ClobberRegs.end()),
                      ClobberRegs.end());
    Clobbers.assign(ClobberRegs.size(), std::string());
    for (unsigned I = 0, E = ClobberRegs.size(); I != E; ++I) {
      raw_string_ostream OS(Clobbers[I]);
      IP->printRegName(OS, ClobberRegs[I]);
    }
  
    // Merge the various outputs and inputs.  Output are expected first.
    if (NumOutputs || NumInputs) {
      unsigned NumExprs = NumOutputs + NumInputs;
      OpDecls.resize(NumExprs);
      Constraints.resize(NumExprs);
      for (unsigned i = 0; i < NumOutputs; ++i) {
        OpDecls[i] = std::make_pair(OutputDecls[i], OutputDeclsAddressOf[i]);
        Constraints[i] = OutputConstraints[i];
      }
      for (unsigned i = 0, j = NumOutputs; i < NumInputs; ++i, ++j) {
        OpDecls[j] = std::make_pair(InputDecls[i], InputDeclsAddressOf[i]);
        Constraints[j] = InputConstraints[i];
      }
    }
  
    // Build the IR assembly string.
    std::string AsmStringIR;
    raw_string_ostream OS(AsmStringIR);
    StringRef ASMString =
        SrcMgr.getMemoryBuffer(SrcMgr.getMainFileID())->getBuffer();
    const char *AsmStart = ASMString.begin();
    const char *AsmEnd = ASMString.end();
    array_pod_sort(AsmStrRewrites.begin(), AsmStrRewrites.end(), rewritesSort);
    for (const AsmRewrite &AR : AsmStrRewrites) {
      AsmRewriteKind Kind = AR.Kind;
      if (Kind == AOK_Delete)
        continue;
  
      const char *Loc = AR.Loc.getPointer();
      assert(Loc >= AsmStart && "Expected Loc to be at or after Start!");
  
      // Emit everything up to the immediate/expression.
      if (unsigned Len = Loc - AsmStart)
        OS << StringRef(AsmStart, Len);
  
      // Skip the original expression.
      if (Kind == AOK_Skip) {
        AsmStart = Loc + AR.Len;
        continue;
      }
  
      unsigned AdditionalSkip = 0;
      // Rewrite expressions in $N notation.
      switch (Kind) {
      default:
        break;
      case AOK_Imm:
        OS << "$$" << AR.Val;
        break;
      case AOK_ImmPrefix:
        OS << "$$";
        break;
      case AOK_Label:
        OS << Ctx.getAsmInfo()->getPrivateLabelPrefix() << AR.Label;
        break;
      case AOK_Input:
        OS << '$' << InputIdx++;
        break;
      case AOK_Output:
        OS << '$' << OutputIdx++;
        break;
      case AOK_SizeDirective:
        switch (AR.Val) {
        default: break;
        case 8:  OS << "byte ptr "; break;
        case 16: OS << "word ptr "; break;
        case 32: OS << "dword ptr "; break;
        case 64: OS << "qword ptr "; break;
        case 80: OS << "xword ptr "; break;
        case 128: OS << "xmmword ptr "; break;
        case 256: OS << "ymmword ptr "; break;
        }
        break;
      case AOK_Emit:
        OS << ".byte";
        break;
      case AOK_Align: {
        // MS alignment directives are measured in bytes. If the native assembler
        // measures alignment in bytes, we can pass it straight through.
        OS << ".align";
        if (getContext().getAsmInfo()->getAlignmentIsInBytes())
          break;
  
        // Alignment is in log2 form, so print that instead and skip the original
        // immediate.
        unsigned Val = AR.Val;
        OS << ' ' << Val;
        assert(Val < 10 && "Expected alignment less then 2^10.");
        AdditionalSkip = (Val < 4) ? 2 : Val < 7 ? 3 : 4;
        break;
      }
      case AOK_EVEN:
        OS << ".even";
        break;
      case AOK_DotOperator:
        // Insert the dot if the user omitted it.
        OS.flush();
        if (AsmStringIR.back() != '.')
          OS << '.';
        OS << AR.Val;
        break;
      }
  
      // Skip the original expression.
      AsmStart = Loc + AR.Len + AdditionalSkip;
    }
  
    // Emit the remainder of the asm string.
    if (AsmStart != AsmEnd)
      OS << StringRef(AsmStart, AsmEnd - AsmStart);
  
    AsmString = OS.str();
    return false;
  }
  
  namespace llvm {
  namespace MCParserUtils {
  
  /// Returns whether the given symbol is used anywhere in the given expression,
  /// or subexpressions.
  static bool isSymbolUsedInExpression(const MCSymbol *Sym, const MCExpr *Value) {
    switch (Value->getKind()) {
    case MCExpr::Binary: {
      const MCBinaryExpr *BE = static_cast<const MCBinaryExpr *>(Value);
      return isSymbolUsedInExpression(Sym, BE->getLHS()) ||
             isSymbolUsedInExpression(Sym, BE->getRHS());
    }
    case MCExpr::Target:
    case MCExpr::Constant:
      return false;
    case MCExpr::SymbolRef: {
      const MCSymbol &S =
          static_cast<const MCSymbolRefExpr *>(Value)->getSymbol();
      if (S.isVariable())
        return isSymbolUsedInExpression(Sym, S.getVariableValue());
      return &S == Sym;
    }
    case MCExpr::Unary:
      return isSymbolUsedInExpression(
          Sym, static_cast<const MCUnaryExpr *>(Value)->getSubExpr());
    }
  
    llvm_unreachable("Unknown expr kind!");
  }
  
  bool parseAssignmentExpression(StringRef Name, bool allow_redef,
                                 MCAsmParser &Parser, MCSymbol *&Sym,
                                 const MCExpr *&Value) {
    MCAsmLexer &Lexer = Parser.getLexer();
  
    // FIXME: Use better location, we should use proper tokens.
    SMLoc EqualLoc = Lexer.getLoc();
  
    if (Parser.parseExpression(Value)) {
      Parser.TokError("missing expression");
      Parser.eatToEndOfStatement();
      return true;
    }
  
    // Note: we don't count b as used in "a = b". This is to allow
    // a = b
    // b = c
  
    if (Lexer.isNot(AsmToken::EndOfStatement))
      return Parser.TokError("unexpected token in assignment");
  
    // Eat the end of statement marker.
    Parser.Lex();
  
    // Validate that the LHS is allowed to be a variable (either it has not been
    // used as a symbol, or it is an absolute symbol).
    Sym = Parser.getContext().lookupSymbol(Name);
    if (Sym) {
      // Diagnose assignment to a label.
      //
      // FIXME: Diagnostics. Note the location of the definition as a label.
      // FIXME: Diagnose assignment to protected identifier (e.g., register name).
      if (isSymbolUsedInExpression(Sym, Value))
        return Parser.Error(EqualLoc, "Recursive use of '" + Name + "'");
      else if (Sym->isUndefined(/*SetUsed*/ false) && !Sym->isUsed() &&
               !Sym->isVariable())
        ; // Allow redefinitions of undefined symbols only used in directives.
      else if (Sym->isVariable() && !Sym->isUsed() && allow_redef)
        ; // Allow redefinitions of variables that haven't yet been used.
      else if (!Sym->isUndefined() && (!Sym->isVariable() || !allow_redef))
        return Parser.Error(EqualLoc, "redefinition of '" + Name + "'");
      else if (!Sym->isVariable())
        return Parser.Error(EqualLoc, "invalid assignment to '" + Name + "'");
      else if (!isa<MCConstantExpr>(Sym->getVariableValue()))
        return Parser.Error(EqualLoc,
                            "invalid reassignment of non-absolute variable '" +
                                Name + "'");
    } else if (Name == ".") {
      Parser.getStreamer().emitValueToOffset(Value, 0);
      return false;
    } else
      Sym = Parser.getContext().getOrCreateSymbol(Name);
  
    Sym->setRedefinable(allow_redef);
  
    return false;
  }
  
  } // namespace MCParserUtils
  } // namespace llvm
  
  /// \brief Create an MCAsmParser instance.
  MCAsmParser *llvm::createMCAsmParser(SourceMgr &SM, MCContext &C,
                                       MCStreamer &Out, const MCAsmInfo &MAI) {
    return new AsmParser(SM, C, Out, MAI);
  }
  