text: //===- AsmParser.cpp - Parser for Assembly Files --------------------------===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  //
  // This class implements the parser for assembly files.
  //
  //===----------------------------------------------------------------------===//
  
  #include "llvm/ADT/APFloat.h"
  #include "llvm/ADT/APInt.h"
  #include "llvm/ADT/ArrayRef.h"
  #include "llvm/ADT/None.h"
  #include "llvm/ADT/STLExtras.h"
  #include "llvm/ADT/SmallString.h"
  #include "llvm/ADT/SmallVector.h"
  #include "llvm/ADT/StringExtras.h"
  #include "llvm/ADT/StringMap.h"
  #include "llvm/ADT/StringRef.h"
  #include "llvm/ADT/Twine.h"
  #include "llvm/BinaryFormat/Dwarf.h"
  #include "llvm/DebugInfo/CodeView/SymbolRecord.h"
  #include "llvm/MC/MCAsmInfo.h"
  #include "llvm/MC/MCCodeView.h"
  #include "llvm/MC/MCContext.h"
  #include "llvm/MC/MCDirectives.h"
  #include "llvm/MC/MCDwarf.h"
  #include "llvm/MC/MCExpr.h"
  #include "llvm/MC/MCInstPrinter.h"
  #include "llvm/MC/MCInstrDesc.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/MCAsmLexer.h"
  #include "llvm/MC/MCParser/MCAsmParser.h"
  #include "llvm/MC/MCParser/MCAsmParserExtension.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/MCSection.h"
  #include "llvm/MC/MCStreamer.h"
  #include "llvm/MC/MCSymbol.h"
  #include "llvm/MC/MCTargetOptions.h"
  #include "llvm/MC/MCValue.h"
  #include "llvm/Support/Casting.h"
  #include "llvm/Support/CommandLine.h"
  #include "llvm/Support/ErrorHandling.h"
  #include "llvm/Support/MD5.h"
  #include "llvm/Support/MathExtras.h"
  #include "llvm/Support/MemoryBuffer.h"
  #include "llvm/Support/SMLoc.h"
  #include "llvm/Support/SourceMgr.h"
  #include "llvm/Support/raw_ostream.h"
  #include <algorithm>
  #include <cassert>
  #include <cctype>
  #include <climits>
  #include <cstddef>
  #include <cstdint>
  #include <deque>
  #include <memory>
  #include <sstream>
  #include <string>
  #include <tuple>
  #include <utility>
  #include <vector>
  
  using namespace llvm;
  
  MCAsmParserSemaCallback::~MCAsmParserSemaCallback() = default;
  
  static cl::opt<unsigned> AsmMacroMaxNestingDepth(
       "asm-macro-max-nesting-depth", cl::init(20), cl::Hidden,
       cl::desc("The maximum nesting depth allowed for assembly macros."));
  
  namespace {
  
  /// Helper types for tracking macro definitions.
  typedef std::vector<AsmToken> MCAsmMacroArgument;
  typedef std::vector<MCAsmMacroArgument> MCAsmMacroArguments;
  
  /// 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.
    unsigned 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;
  };
  
  struct ParseStatementInfo {
    /// The parsed operands from the last parsed statement.
    SmallVector<std::unique_ptr<MCParsedAsmOperand>, 8> ParsedOperands;
  
    /// The opcode from the last parsed instruction.
    unsigned Opcode = ~0U;
  
    /// Was there an error parsing the inline assembly?
    bool ParseError = false;
  
    SmallVectorImpl<AsmRewrite> *AsmRewrites = nullptr;
  
    ParseStatementInfo() = delete;
    ParseStatementInfo(SmallVectorImpl<AsmRewrite> *rewrites)
      : AsmRewrites(rewrites) {}
  };
  
  /// The concrete assembly parser instance.
  class AsmParser : public MCAsmParser {
  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;
  
    /// maps directive names to handler methods in parser
    /// extensions. Extensions register themselves in this map by calling
    /// addDirectiveHandler.
    StringMap<ExtensionDirectiveHandler> ExtensionDirectiveMap;
  
    /// Stack of active macro instantiations.
    std::vector<MacroInstantiation*> ActiveMacros;
  
    /// List of bodies of anonymous macros.
    std::deque<MCAsmMacro> MacroLikeBodies;
  
    /// Boolean tracking whether macro substitution is enabled.
    unsigned MacrosEnabledFlag : 1;
  
    /// Keeps track of how many .macro's have been instantiated.
    unsigned NumOfMacroInstantiations;
  
    /// The values from the last parsed cpp hash file line comment if any.
    struct CppHashInfoTy {
      StringRef Filename;
      int64_t LineNumber;
      SMLoc Loc;
      unsigned Buf;
      CppHashInfoTy() : Filename(), LineNumber(0), Loc(), Buf(0) {}
    };
    CppHashInfoTy CppHashInfo;
  
    /// The filename from the first cpp hash file line comment, if any.
    StringRef FirstCppHashFilename;
  
    /// List of forward directional labels for diagnosis at the end.
    SmallVector<std::tuple<SMLoc, CppHashInfoTy, MCSymbol *>, 4> DirLabels;
  
    /// AssemblerDialect. ~OU means unset value and use value provided by MAI.
    unsigned AssemblerDialect = ~0U;
  
    /// is Darwin compatibility enabled?
    bool IsDarwin = false;
  
    /// Are we parsing ms-style inline assembly?
    bool ParsingInlineAsm = false;
  
    /// Did we already inform the user about inconsistent MD5 usage?
    bool ReportedInconsistentMD5 = false;
  
    // Is alt macro mode enabled.
    bool AltMacroMode = false;
  
  public:
    AsmParser(SourceMgr &SM, MCContext &Ctx, MCStreamer &Out,
              const MCAsmInfo &MAI, unsigned CB);
    AsmParser(const AsmParser &) = delete;
    AsmParser &operator=(const AsmParser &) = delete;
    ~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];
    }
  
    /// @name MCAsmParser Interface
    /// {
  
    SourceMgr &getSourceManager() override { return SrcMgr; }
    MCAsmLexer &getLexer() override { return Lexer; }
    MCContext &getContext() override { return Ctx; }
    MCStreamer &getStreamer() override { return Out; }
  
    CodeViewContext &getCVContext() { return Ctx.getCVContext(); }
  
    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, SMRange Range = None) override;
    bool Warning(SMLoc L, const Twine &Msg, SMRange Range = None) override;
    bool printError(SMLoc L, const Twine &Msg, SMRange Range = None) override;
  
    const AsmToken &Lex() override;
  
    void setParsingInlineAsm(bool V) override {
      ParsingInlineAsm = V;
      // When parsing MS inline asm, we must lex 0b1101 and 0ABCH as binary and
      // hex integer literals.
      Lexer.setLexMasmIntegers(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;
  
    /// Parse a floating point expression using the float \p Semantics
    /// and set \p Res to the value.
    bool parseRealValue(const fltSemantics &Semantics, APInt &Res);
  
    /// 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;
  
    bool checkForValidSection() override;
  
    /// }
  
  private:
    bool parseStatement(ParseStatementInfo &Info,
                        MCAsmParserSemaCallback *SI);
    bool parseCurlyBlockScope(SmallVectorImpl<AsmRewrite>& AsmStrRewrites);
    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);
  
    /// Are macros enabled in the parser?
    bool areMacrosEnabled() {return MacrosEnabledFlag;}
  
    /// Control a flag in the parser that enables or disables macros.
    void setMacrosEnabled(bool Flag) {MacrosEnabledFlag = Flag;}
  
    /// Are we inside a macro instantiation?
    bool isInsideMacroInstantiation() {return !ActiveMacros.empty();}
  
    /// Handle entry to macro instantiation.
    ///
    /// \param M The macro.
    /// \param NameLoc Instantiation location.
    bool handleMacroEntry(const MCAsmMacro *M, SMLoc NameLoc);
  
    /// Handle exit from macro instantiation.
    void handleMacroExit();
  
    /// Extract AsmTokens for a macro argument.
    bool parseMacroArgument(MCAsmMacroArgument &MA, bool Vararg);
  
    /// 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,
                      SMRange Range = None) const {
      ArrayRef<SMRange> Ranges(Range);
      SrcMgr.PrintMessage(Loc, Kind, Msg, Ranges);
    }
    static void DiagHandler(const SMDiagnostic &Diag, void *Context);
  
    /// Should we emit DWARF describing this assembler source?  (Returns false if
    /// the source has .file directives, which means we don't want to generate
    /// info describing the assembler source itself.)
    bool enabledGenDwarfForAssembly();
  
    /// Enter the specified file. This returns true on failure.
    bool enterIncludeFile(const std::string &Filename);
  
    /// Process the specified file for the .incbin directive.
    /// This returns true on failure.
    bool processIncbinFile(const std::string &Filename, int64_t Skip = 0,
                           const MCExpr *Count = nullptr, SMLoc Loc = SMLoc());
  
    /// 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);
  
    /// 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;
  
    /// 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);
  
    bool parseCVFunctionId(int64_t &FunctionId, StringRef DirectiveName);
    bool parseCVFileId(int64_t &FileId, StringRef DirectiveName);
  
    // 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_DC,
      DK_DC_A,
      DK_DC_B,
      DK_DC_D,
      DK_DC_L,
      DK_DC_S,
      DK_DC_W,
      DK_DC_X,
      DK_DCB,
      DK_DCB_B,
      DK_DCB_D,
      DK_DCB_L,
      DK_DCB_S,
      DK_DCB_W,
      DK_DCB_X,
      DK_DS,
      DK_DS_B,
      DK_DS_D,
      DK_DS_L,
      DK_DS_P,
      DK_DS_S,
      DK_DS_W,
      DK_DS_X,
      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_COLD,
      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_FUNC_ID,
      DK_CV_INLINE_SITE_ID,
      DK_CV_LOC,
      DK_CV_LINETABLE,
      DK_CV_INLINE_LINETABLE,
      DK_CV_DEF_RANGE,
      DK_CV_STRINGTABLE,
      DK_CV_STRING,
      DK_CV_FILECHECKSUMS,
      DK_CV_FILECHECKSUM_OFFSET,
      DK_CV_FPO_DATA,
      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_RETURN_COLUMN,
      DK_CFI_SIGNAL_FRAME,
      DK_CFI_UNDEFINED,
      DK_CFI_REGISTER,
      DK_CFI_WINDOW_SAVE,
      DK_CFI_B_KEY_FRAME,
      DK_MACROS_ON,
      DK_MACROS_OFF,
      DK_ALTMACRO,
      DK_NOALTMACRO,
      DK_MACRO,
      DK_EXITM,
      DK_ENDM,
      DK_ENDMACRO,
      DK_PURGEM,
      DK_SLEB128,
      DK_ULEB128,
      DK_ERR,
      DK_ERROR,
      DK_WARNING,
      DK_PRINT,
      DK_ADDRSIG,
      DK_ADDRSIG_SYM,
      DK_END
    };
  
    /// Maps directive name --> DirectiveKind enum, for
    /// directives parsed by this class.
    StringMap<DirectiveKind> DirectiveKindMap;
  
    // Codeview def_range type parsing.
    enum CVDefRangeType {
      CVDR_DEFRANGE = 0, // Placeholder
      CVDR_DEFRANGE_REGISTER,
      CVDR_DEFRANGE_FRAMEPOINTER_REL,
      CVDR_DEFRANGE_SUBFIELD_REGISTER,
      CVDR_DEFRANGE_REGISTER_REL
    };
  
    /// Maps Codeview def_range types --> CVDefRangeType enum, for
    /// Codeview def_range types parsed by this class.
    StringMap<CVDefRangeType> CVDefRangeTypeMap;
  
    // ".ascii", ".asciz", ".string"
    bool parseDirectiveAscii(StringRef IDVal, bool ZeroTerminated);
    bool parseDirectiveReloc(SMLoc DirectiveLoc); // ".reloc"
    bool parseDirectiveValue(StringRef IDVal,
                             unsigned Size);       // ".byte", ".long", ...
    bool parseDirectiveOctaValue(StringRef IDVal); // ".octa", ...
    bool parseDirectiveRealValue(StringRef IDVal,
                                 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_func_id", ".cv_inline_site_id", ".cv_loc", ".cv_linetable",
    // ".cv_inline_linetable", ".cv_def_range", ".cv_string"
    bool parseDirectiveCVFile();
    bool parseDirectiveCVFuncId();
    bool parseDirectiveCVInlineSiteId();
    bool parseDirectiveCVLoc();
    bool parseDirectiveCVLinetable();
    bool parseDirectiveCVInlineLinetable();
    bool parseDirectiveCVDefRange();
    bool parseDirectiveCVString();
    bool parseDirectiveCVStringTable();
    bool parseDirectiveCVFileChecksums();
    bool parseDirectiveCVFileChecksumOffset();
    bool parseDirectiveCVFPOData();
  
    // .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 parseDirectiveCFIReturnColumn(SMLoc DirectiveLoc);
    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);
    // alternate macro mode directives
    bool parseDirectiveAltmacro(StringRef Directive);
    // ".bundle_align_mode"
    bool parseDirectiveBundleAlignMode();
    // ".bundle_lock"
    bool parseDirectiveBundleLock();
    // ".bundle_unlock"
    bool parseDirectiveBundleUnlock();
  
    // ".space", ".skip"
    bool parseDirectiveSpace(StringRef IDVal);
  
    // ".dcb"
    bool parseDirectiveDCB(StringRef IDVal, unsigned Size);
    bool parseDirectiveRealDCB(StringRef IDVal, const fltSemantics &);
    // ".ds"
    bool parseDirectiveDS(StringRef IDVal, unsigned Size);
  
    // .sleb128 (Signed=true) and .uleb128 (Signed=false)
    bool parseDirectiveLEB128(bool Signed);
  
    /// 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);
  
    // .print <double-quotes-string>
    bool parseDirectivePrint(SMLoc DirectiveLoc);
  
    // Directives to support address-significance tables.
    bool parseDirectiveAddrsig();
    bool parseDirectiveAddrsigSym();
  
    void initializeDirectiveKindMap();
    void initializeCVDefRangeTypeMap();
  };
  
  } // end anonymous namespace
  
  namespace llvm {
  
  extern MCAsmParserExtension *createDarwinAsmParser();
  extern MCAsmParserExtension *createELFAsmParser();
  extern MCAsmParserExtension *createCOFFAsmParser();
  extern MCAsmParserExtension *createWasmAsmParser();
  
  } // end namespace llvm
  
  enum { DEFAULT_ADDRSPACE = 0 };
  
  AsmParser::AsmParser(SourceMgr &SM, MCContext &Ctx, MCStreamer &Out,
                       const MCAsmInfo &MAI, unsigned CB = 0)
      : Lexer(MAI), Ctx(Ctx), Out(Out), MAI(MAI), SrcMgr(SM),
        CurBuffer(CB ? CB : SM.getMainFileID()), MacrosEnabledFlag(true) {
    HadError = 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;
    case MCObjectFileInfo::IsWasm:
      PlatformParser.reset(createWasmAsmParser());
      break;
    case MCObjectFileInfo::IsXCOFF:
      report_fatal_error(
          "Need to implement createXCOFFAsmParser for XCOFF format.");
      break;
    }
  
    PlatformParser->Initialize(*this);
    initializeDirectiveKindMap();
    initializeCVDefRangeTypeMap();
  
    NumOfMacroInstantiations = 0;
  }
  
  AsmParser::~AsmParser() {
    assert((HadError || ActiveMacros.empty()) &&
           "Unexpected active macro instantiation!");
  
    // Restore the saved diagnostics handler and context for use during
    // finalization.
    SrcMgr.setDiagHandler(SavedDiagHandler, SavedDiagContext);
  }
  
  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, SMRange Range) {
    printPendingErrors();
    printMessage(L, SourceMgr::DK_Note, Msg, Range);
    printMacroInstantiations();
  }
  
  bool AsmParser::Warning(SMLoc L, const Twine &Msg, SMRange Range) {
    if(getTargetParser().getTargetOptions().MCNoWarn)
      return false;
    if (getTargetParser().getTargetOptions().MCFatalWarnings)
      return Error(L, Msg, Range);
    printMessage(L, SourceMgr::DK_Warning, Msg, Range);
    printMacroInstantiations();
    return false;
  }
  
  bool AsmParser::printError(SMLoc L, const Twine &Msg, SMRange Range) {
    HadError = true;
    printMessage(L, SourceMgr::DK_Error, Msg, Range);
    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, int64_t Skip,
                                    const MCExpr *Count, SMLoc Loc) {
    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.
    StringRef Bytes = SrcMgr.getMemoryBuffer(NewBuf)->getBuffer();
    Bytes = Bytes.drop_front(Skip);
    if (Count) {
      int64_t Res;
      if (!Count->evaluateAsAbsolute(Res, getStreamer().getAssemblerPtr()))
        return Error(Loc, "expected absolute expression");
      if (Res < 0)
        return Warning(Loc, "negative count has no effect");
      Bytes = Bytes.take_front(Res);
    }
    getStreamer().EmitBytes(Bytes);
    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() {
    if (Lexer.getTok().is(AsmToken::Error))
      Error(Lexer.getErrLoc(), Lexer.getErr());
  
    // if it's a end of statement with a comment in it
    if (getTok().is(AsmToken::EndOfStatement)) {
      // if this is a line comment output it.
      if (!getTok().getString().empty() && getTok().getString().front() != '\n' &&
          getTok().getString().front() != '\r' && MAI.preserveAsmComments())
        Out.addExplicitComment(Twine(getTok().getString()));
    }
  
    const AsmToken *tok = &Lexer.Lex();
  
    // Parse comments here to be deferred until end of next statement.
    while (tok->is(AsmToken::Comment)) {
      if (MAI.preserveAsmComments())
        Out.addExplicitComment(Twine(tok->getString()));
      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);
        return Lex();
      }
    }
  
    return *tok;
  }
  
  bool AsmParser::enabledGenDwarfForAssembly() {
    // Check whether the user specified -g.
    if (!getContext().getGenDwarfForAssembly())
      return false;
    // If we haven't encountered any .file directives (which would imply that
    // the assembler source was produced with debug info already) then emit one
    // describing the assembler source file itself.
    if (getContext().getGenDwarfFileNumber() == 0) {
      // Use the first #line directive for this, if any. It's preprocessed, so
      // there is no checksum, and of course no source directive.
      if (!FirstCppHashFilename.empty())
        getContext().setMCLineTableRootFile(/*CUID=*/0,
                                            getContext().getCompilationDir(),
                                            FirstCppHashFilename,
                                            /*Cksum=*/None, /*Source=*/None);
      const MCDwarfFile &RootFile =
          getContext().getMCDwarfLineTable(/*CUID=*/0).getRootFile();
      getContext().setGenDwarfFileNumber(getStreamer().EmitDwarfFileDirective(
          /*CUID=*/0, getContext().getCompilationDir(), RootFile.Name,
          RootFile.Checksum, RootFile.Source));
    }
    return true;
  }
  
  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;
    SmallVector<AsmRewrite, 4> AsmStrRewrites;
  
    // If we are generating dwarf for assembly source files save the initial text
    // section.  (Don't use enabledGenDwarfForAssembly() here, as we aren't
    // emitting any actual debug info yet and haven't had a chance to parse any
    // embedded .file directives.)
    if (getContext().getGenDwarfForAssembly()) {
      MCSection *Sec = getStreamer().getCurrentSectionOnly();
      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;
    }
  
    // While we have input, parse each statement.
    while (Lexer.isNot(AsmToken::Eof)) {
      ParseStatementInfo Info(&AsmStrRewrites);
      bool Parsed = parseStatement(Info, nullptr);
  
      // If we have a Lexer Error we are on an Error Token. Load in Lexer Error
      // for printing ErrMsg via Lex() only if no (presumably better) parser error
      // exists.
      if (Parsed && !hasPendingError() && Lexer.getTok().is(AsmToken::Error)) {
        Lex();
      }
  
      // parseStatement returned true so may need to emit an error.
      printPendingErrors();
  
      // Skipping to the next line if needed.
      if (Parsed && !getLexer().isAtStartOfStatement())
        eatToEndOfStatement();
    }
  
    getTargetParser().onEndOfFile();
    printPendingErrors();
  
    // All errors should have been emitted.
    assert(!hasPendingError() && "unexpected error from parseStatement");
  
    getTargetParser().flushPendingInstructions(getStreamer());
  
    if (TheCondState.TheCond != StartingCondState.TheCond ||
        TheCondState.Ignore != StartingCondState.Ignore)
      printError(getTok().getLoc(), "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)
          printError(getTok().getLoc(), "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) {
      if (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.
            printError(getTok().getLoc(), "assembler local symbol '" +
                                              Sym->getName() + "' not defined");
        }
      }
  
      // Temporary symbols like the ones for directional jumps don't go in the
      // symbol table. They also need to be diagnosed in all (final) cases.
      for (std::tuple<SMLoc, CppHashInfoTy, MCSymbol *> &LocSym : DirLabels) {
        if (std::get<2>(LocSym)->isUndefined()) {
          // Reset the state of any "# line file" directives we've seen to the
          // context as it was at the diagnostic site.
          CppHashInfo = std::get<1>(LocSym);
          printError(std::get<0>(LocSym), "directional label undefined");
        }
      }
    }
  
    // 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();
  }
  
  bool AsmParser::checkForValidSection() {
    if (!ParsingInlineAsm && !getStreamer().getCurrentSectionOnly()) {
      Out.InitSections(false);
      return Error(getTok().getLoc(),
                   "expected section directive before assembly directive");
    }
    return false;
  }
  
  /// Throw away the rest of the line for testing purposes.
  void AsmParser::eatToEndOfStatement() {
    while (Lexer.isNot(AsmToken::EndOfStatement) && Lexer.isNot(AsmToken::Eof))
      Lexer.Lex();
  
    // Eat EOL.
    if (Lexer.is(AsmToken::EndOfStatement))
      Lexer.Lex();
  }
  
  StringRef AsmParser::parseStringToEndOfStatement() {
    const char *Start = getTok().getLoc().getPointer();
  
    while (Lexer.isNot(AsmToken::EndOfStatement) && Lexer.isNot(AsmToken::Eof))
      Lexer.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))
      Lexer.Lex();
  
    const char *End = getTok().getLoc().getPointer();
    return StringRef(Start, End - Start);
  }
  
  /// 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;
  }
  
  /// 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;
    EndLoc = getTok().getEndLoc();
    if (parseToken(AsmToken::RBrac, "expected ']' in brackets expression"))
      return true;
    return false;
  }
  
  /// 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(), FirstTokenLoc);
      return false;
    case AsmToken::Dollar:
    case AsmToken::At:
    case AsmToken::String:
    case AsmToken::Identifier: {
      StringRef Identifier;
      if (parseIdentifier(Identifier)) {
        // We may have failed but $ may be a valid token.
        if (getTok().is(AsmToken::Dollar)) {
          if (Lexer.getMAI().getDollarIsPC()) {
            Lex();
            // 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)) {
            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)) {
        Lex(); // eat '('.
        StringRef VName;
        parseIdentifier(VName);
        // eat ')'.
        if (parseToken(AsmToken::RParen,
                       "unexpected token in variant, expected ')'"))
          return true;
        Split = std::make_pair(Identifier, VName);
      }
  
      EndLoc = SMLoc::getFromPointer(Identifier.end());
  
      // This is a symbol reference.
      StringRef SymbolName = Identifier;
      if (SymbolName.empty())
        return Error(getLexer().getLoc(), "expected a symbol reference");
  
      MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
  
      // Lookup the symbol variant if used.
      if (!Split.second.empty()) {
        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().getInlineAsmLabel(SymbolName);
      if (!Sym)
        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()) {
        auto V = Sym->getVariableValue(/*SetUsed*/ false);
        bool DoInline = isa<MCConstantExpr>(V) && !Variant;
        if (auto TV = dyn_cast<MCTargetExpr>(V))
          DoInline = TV->inlineAssignedExpr();
        if (DoInline) {
          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(), FirstTokenLoc);
      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, "directional label undefined");
          DirLabels.push_back(std::make_tuple(Loc, CppHashInfo, Sym));
          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(), FirstTokenLoc);
      return false;
    case AsmToken::Plus:
      Lex(); // Eat the operator.
      if (parsePrimaryExpr(Res, EndLoc))
        return true;
      Res = MCUnaryExpr::createPlus(Res, getContext(), FirstTokenLoc);
      return false;
    case AsmToken::Tilde:
      Lex(); // Eat the operator.
      if (parsePrimaryExpr(Res, EndLoc))
        return true;
      Res = MCUnaryExpr::createNot(Res, getContext(), FirstTokenLoc);
      return false;
    // MIPS unary expression operators. The lexer won't generate these tokens if
    // MCAsmInfo::HasMipsExpressions is false for the target.
    case AsmToken::PercentCall16:
    case AsmToken::PercentCall_Hi:
    case AsmToken::PercentCall_Lo:
    case AsmToken::PercentDtprel_Hi:
    case AsmToken::PercentDtprel_Lo:
    case AsmToken::PercentGot:
    case AsmToken::PercentGot_Disp:
    case AsmToken::PercentGot_Hi:
    case AsmToken::PercentGot_Lo:
    case AsmToken::PercentGot_Ofst:
    case AsmToken::PercentGot_Page:
    case AsmToken::PercentGottprel:
    case AsmToken::PercentGp_Rel:
    case AsmToken::PercentHi:
    case AsmToken::PercentHigher:
    case AsmToken::PercentHighest:
    case AsmToken::PercentLo:
    case AsmToken::PercentNeg:
    case AsmToken::PercentPcrel_Hi:
    case AsmToken::PercentPcrel_Lo:
    case AsmToken::PercentTlsgd:
    case AsmToken::PercentTlsldm:
    case AsmToken::PercentTprel_Hi:
    case AsmToken::PercentTprel_Lo:
      Lex(); // Eat the operator.
      if (Lexer.isNot(AsmToken::LParen))
        return TokError("expected '(' after operator");
      Lex(); // Eat the operator.
      if (parseExpression(Res, EndLoc))
        return true;
      if (Lexer.isNot(AsmToken::RParen))
        return TokError("expected ')'");
      Lex(); // Eat the operator.
      Res = getTargetParser().createTargetUnaryExpr(Res, FirstTokenKind, Ctx);
      return !Res;
    }
  }
  
  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!");
  }
  
  /// This function checks if the next token is <string> type or arithmetic.
  /// string that begin with character '<' must end with character '>'.
  /// otherwise it is arithmetics.
  /// If the function returns a 'true' value,
  /// the End argument will be filled with the last location pointed to the '>'
  /// character.
  
  /// There is a gap between the AltMacro's documentation and the single quote
  /// implementation. GCC does not fully support this feature and so we will not
  /// support it.
  /// TODO: Adding single quote as a string.
  static bool isAltmacroString(SMLoc &StrLoc, SMLoc &EndLoc) {
    assert((StrLoc.getPointer() != nullptr) &&
           "Argument to the function cannot be a NULL value");
    const char *CharPtr = StrLoc.getPointer();
    while ((*CharPtr != '>') && (*CharPtr != '\n') && (*CharPtr != '\r') &&
           (*CharPtr != '\0')) {
      if (*CharPtr == '!')
        CharPtr++;
      CharPtr++;
    }
    if (*CharPtr == '>') {
      EndLoc = StrLoc.getFromPointer(CharPtr + 1);
      return true;
    }
    return false;
  }
  
  /// creating a string without the escape characters '!'.
  static std::string altMacroString(StringRef AltMacroStr) {
    std::string Res;
    for (size_t Pos = 0; Pos < AltMacroStr.size(); Pos++) {
      if (AltMacroStr[Pos] == '!')
        Pos++;
      Res += AltMacroStr[Pos];
    }
    return Res;
  }
  
  /// 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 (getTargetParser().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. Do not exploit
    // assembler here.
    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) {
        EndLoc = getTok().getEndLoc();
        if (parseToken(AsmToken::RParen,
                       "expected ')' in parentheses expression"))
          return true;
      }
    }
    return false;
  }
  
  bool AsmParser::parseAbsoluteExpression(int64_t &Res) {
    const MCExpr *Expr;
  
    SMLoc StartLoc = Lexer.getLoc();
    if (parseExpression(Expr))
      return true;
  
    if (!Expr->evaluateAsAbsolute(Res, getStreamer().getAssemblerPtr()))
      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);
  }
  
  /// 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) {
    SMLoc StartLoc = Lexer.getLoc();
    while (true) {
      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 (getTargetParser().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(), StartLoc);
    }
  }
  
  /// ParseStatement:
  ///   ::= EndOfStatement
  ///   ::= Label* Directive ...Operands... EndOfStatement
  ///   ::= Label* Identifier OperandList* EndOfStatement
  bool AsmParser::parseStatement(ParseStatementInfo &Info,
                                 MCAsmParserSemaCallback *SI) {
    assert(!hasPendingError() && "parseStatement started with pending error");
    // Eat initial spaces and comments
    while (Lexer.is(AsmToken::Space))
      Lex();
    if (Lexer.is(AsmToken::EndOfStatement)) {
      // if this is a line comment we can drop it safely
      if (getTok().getString().empty() || getTok().getString().front() == '\r' ||
          getTok().getString().front() == '\n')
        Out.AddBlankLine();
      Lex();
      return false;
    }
    // Statements always start with an identifier.
    AsmToken ID = getTok();
    SMLoc IDLoc = ID.getLoc();
    StringRef IDVal;
    int64_t LocalLabelVal = -1;
    if (Lexer.is(AsmToken::HashDirective))
      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) {
          Lex(); // always eat a token
          return Error(IDLoc, "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) {
            Lex(); // always eat a token
            return Error(IDLoc, "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 (Lexer.is(AsmToken::Star) &&
               getTargetParser().starIsStartOfStatement()) {
      // Accept '*' as a valid start of statement.
      Lex();
      IDVal = "*";
    } else if (parseIdentifier(IDVal)) {
      if (!TheCondState.Ignore) {
        Lex(); // always eat a token
        return Error(IDLoc, "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;
      if (checkForValidSection())
        return true;
  
      // 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.empty() &&
                 "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);
      // End of Labels should be treated as end of line for lexing
      // purposes but that information is not available to the Lexer who
      // does not understand Labels. This may cause us to see a Hash
      // here instead of a preprocessor line comment.
      if (getTok().is(AsmToken::Hash)) {
        StringRef CommentStr = parseStringToEndOfStatement();
        Lexer.Lex();
        Lexer.UnLex(AsmToken(AsmToken::EndOfStatement, CommentStr));
      }
  
      // Consume any end of statement token, if present, to avoid spurious
      // AddBlankLine calls().
      if (getTok().is(AsmToken::EndOfStatement)) {
        Lex();
      }
  
      getTargetParser().doBeforeLabelEmit(Sym);
  
      // Emit the label.
      if (!getTargetParser().isParsingInlineAsm())
        Out.EmitLabel(Sym, IDLoc);
  
      // 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 (enabledGenDwarfForAssembly())
        MCGenDwarfLabelEntry::Make(Sym, &getStreamer(), getSourceManager(),
                                   IDLoc);
  
      getTargetParser().onLabelParsed(Sym);
  
      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 = getContext().lookupMacro(IDVal)) {
        return handleMacroEntry(M, IDLoc);
      }
  
    // Otherwise, we have a normal instruction or directive.
  
    // Directives start with "."
    if (IDVal.startswith(".") && 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.
  
      getTargetParser().flushPendingInstructions(getStreamer());
  
      SMLoc StartTokLoc = getTok().getLoc();
      bool TPDirectiveReturn = getTargetParser().ParseDirective(ID);
  
      if (hasPendingError())
        return true;
      // Currently the return value should be true if we are
      // uninterested but as this is at odds with the standard parsing
      // convention (return true = error) we have instances of a parsed
      // directive that fails returning true as an error. Catch these
      // cases as best as possible errors here.
      if (TPDirectiveReturn && StartTokLoc != getTok().getLoc())
        return true;
      // Return if we did some parsing or believe we succeeded.
      if (!TPDirectiveReturn || StartTokLoc != getTok().getLoc())
        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:
      case DK_DC_B:
        return parseDirectiveValue(IDVal, 1);
      case DK_DC:
      case DK_DC_W:
      case DK_SHORT:
      case DK_VALUE:
      case DK_2BYTE:
        return parseDirectiveValue(IDVal, 2);
      case DK_LONG:
      case DK_INT:
      case DK_4BYTE:
      case DK_DC_L:
        return parseDirectiveValue(IDVal, 4);
      case DK_QUAD:
      case DK_8BYTE:
        return parseDirectiveValue(IDVal, 8);
      case DK_DC_A:
        return parseDirectiveValue(
            IDVal, getContext().getAsmInfo()->getCodePointerSize());
      case DK_OCTA:
        return parseDirectiveOctaValue(IDVal);
      case DK_SINGLE:
      case DK_FLOAT:
      case DK_DC_S:
        return parseDirectiveRealValue(IDVal, APFloat::IEEEsingle());
      case DK_DOUBLE:
      case DK_DC_D:
        return parseDirectiveRealValue(IDVal, 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_COLD:
        return parseDirectiveSymbolAttribute(MCSA_Cold);
      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 currently supported for this target");
      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_FUNC_ID:
        return parseDirectiveCVFuncId();
      case DK_CV_INLINE_SITE_ID:
        return parseDirectiveCVInlineSiteId();
      case DK_CV_LOC:
        return parseDirectiveCVLoc();
      case DK_CV_LINETABLE:
        return parseDirectiveCVLinetable();
      case DK_CV_INLINE_LINETABLE:
        return parseDirectiveCVInlineLinetable();
      case DK_CV_DEF_RANGE:
        return parseDirectiveCVDefRange();
      case DK_CV_STRING:
        return parseDirectiveCVString();
      case DK_CV_STRINGTABLE:
        return parseDirectiveCVStringTable();
      case DK_CV_FILECHECKSUMS:
        return parseDirectiveCVFileChecksums();
      case DK_CV_FILECHECKSUM_OFFSET:
        return parseDirectiveCVFileChecksumOffset();
      case DK_CV_FPO_DATA:
        return parseDirectiveCVFPOData();
      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_RETURN_COLUMN:
        return parseDirectiveCFIReturnColumn(IDLoc);
      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_ALTMACRO:
      case DK_NOALTMACRO:
        return parseDirectiveAltmacro(IDVal);
      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);
      case DK_DCB:
      case DK_DCB_W:
        return parseDirectiveDCB(IDVal, 2);
      case DK_DCB_B:
        return parseDirectiveDCB(IDVal, 1);
      case DK_DCB_D:
        return parseDirectiveRealDCB(IDVal, APFloat::IEEEdouble());
      case DK_DCB_L:
        return parseDirectiveDCB(IDVal, 4);
      case DK_DCB_S:
        return parseDirectiveRealDCB(IDVal, APFloat::IEEEsingle());
      case DK_DC_X:
      case DK_DCB_X:
        return TokError(Twine(IDVal) +
                        " not currently supported for this target");
      case DK_DS:
      case DK_DS_W:
        return parseDirectiveDS(IDVal, 2);
      case DK_DS_B:
        return parseDirectiveDS(IDVal, 1);
      case DK_DS_D:
        return parseDirectiveDS(IDVal, 8);
      case DK_DS_L:
      case DK_DS_S:
        return parseDirectiveDS(IDVal, 4);
      case DK_DS_P:
      case DK_DS_X:
        return parseDirectiveDS(IDVal, 12);
      case DK_PRINT:
        return parseDirectivePrint(IDLoc);
      case DK_ADDRSIG:
        return parseDirectiveAddrsig();
      case DK_ADDRSIG_SYM:
        return parseDirectiveAddrsigSym();
      }
  
      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" || IDVal == "EVEN"))
      Info.AsmRewrites->emplace_back(AOK_EVEN, IDLoc, 4);
    if (checkForValidSection())
      return true;
  
    // Canonicalize the opcode to lower case.
    std::string OpcodeStr = IDVal.lower();
    ParseInstructionInfo IInfo(Info.AsmRewrites);
    bool ParseHadError = getTargetParser().ParseInstruction(IInfo, OpcodeStr, ID,
                                                            Info.ParsedOperands);
    Info.ParseError = ParseHadError;
  
    // 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());
    }
  
    // Fail even if ParseInstruction erroneously returns false.
    if (hasPendingError() || ParseHadError)
      return true;
  
    // If we are generating dwarf for the current section then generate a .loc
    // directive for the instruction.
    if (!ParseHadError && enabledGenDwarfForAssembly() &&
        getContext().getGenDwarfSectionSyms().count(
            getStreamer().getCurrentSectionOnly())) {
      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 (!CppHashInfo.Filename.empty()) {
        unsigned FileNumber = getStreamer().EmitDwarfFileDirective(
            0, StringRef(), CppHashInfo.Filename);
        getContext().setGenDwarfFileNumber(FileNumber);
  
        unsigned CppHashLocLineNo =
          SrcMgr.FindLineNumber(CppHashInfo.Loc, CppHashInfo.Buf);
        Line = CppHashInfo.LineNumber - 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 (!ParseHadError) {
      uint64_t ErrorInfo;
      if (getTargetParser().MatchAndEmitInstruction(
              IDLoc, Info.Opcode, Info.ParsedOperands, Out, ErrorInfo,
              getTargetParser().isParsingInlineAsm()))
        return true;
    }
    return false;
  }
  
  // Parse and erase curly braces marking block start/end
  bool
  AsmParser::parseCurlyBlockScope(SmallVectorImpl<AsmRewrite> &AsmStrRewrites) {
    // Identify curly brace marking block start/end
    if (Lexer.isNot(AsmToken::LCurly) && Lexer.isNot(AsmToken::RCurly))
      return false;
  
    SMLoc StartLoc = Lexer.getLoc();
    Lex(); // Eat the brace
    if (Lexer.is(AsmToken::EndOfStatement))
      Lex(); // Eat EndOfStatement following the brace
  
    // Erase the block start/end brace from the output asm string
    AsmStrRewrites.emplace_back(AOK_Skip, StartLoc, Lexer.getLoc().getPointer() -
                                                    StartLoc.getPointer());
    return true;
  }
  
  /// parseCppHashLineFilenameComment as this:
  ///   ::= # number "filename"
  bool AsmParser::parseCppHashLineFilenameComment(SMLoc L) {
    Lex(); // Eat the hash token.
    // Lexer only ever emits HashDirective if it fully formed if it's
    // done the checking already so this is an internal error.
    assert(getTok().is(AsmToken::Integer) &&
           "Lexing Cpp line comment: Expected Integer");
    int64_t LineNumber = getTok().getIntVal();
    Lex();
    assert(getTok().is(AsmToken::String) &&
           "Lexing Cpp line comment: Expected String");
    StringRef Filename = getTok().getString();
    Lex();
  
    // Get rid of the enclosing quotes.
    Filename = Filename.substr(1, Filename.size() - 2);
  
    // Save the SMLoc, Filename and LineNumber for later use by diagnostics
    // and possibly DWARF file info.
    CppHashInfo.Loc = L;
    CppHashInfo.Filename = Filename;
    CppHashInfo.LineNumber = LineNumber;
    CppHashInfo.Buf = CurBuffer;
    if (FirstCppHashFilename.empty())
      FirstCppHashFilename = Filename;
    return false;
  }
  
  /// 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->CppHashInfo.Loc);
  
    // 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->CppHashInfo.LineNumber || &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
    // CppHashInfo.Loc and CppHashInfo.LineNumber relative to this Diag's SMLoc
    // for the diagnostic.
    const std::string &Filename = Parser->CppHashInfo.Filename;
  
    int DiagLocLineNo = DiagSrcMgr.FindLineNumber(DiagLoc, DiagBuf);
    int CppHashLocLineNo =
        Parser->SrcMgr.FindLineNumber(Parser->CppHashInfo.Loc, CppHashBuf);
    int LineNo =
        Parser->CppHashInfo.LineNumber - 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])
              // For altmacro mode, you can write '%expr'.
              // The prefix '%' evaluates the expression 'expr'
              // and uses the result as a string (e.g. replace %(1+2) with the
              // string "3").
              // Here, we identify the integer token which is the result of the
              // absolute expression evaluation and replace it with its string
              // representation.
              if (AltMacroMode && Token.getString().front() == '%' &&
                  Token.is(AsmToken::Integer))
                // Emit an integer value to the buffer.
                OS << Token.getIntVal();
              // Only Token that was validated as a string and begins with '<'
              // is considered altMacroString!!!
              else if (AltMacroMode && Token.getString().front() == '<' &&
                       Token.is(AsmToken::String)) {
                OS << altMacroString(Token.getStringContents());
              }
              // We expect no quotes around the string's contents when
              // parsing for varargs.
              else if (Token.isNot(AsmToken::String) || VarargParameter)
                OS << Token.getString();
              else
                OS << Token.getStringContents();
  
            Pos += 1 + Argument.size();
          }
        }
      }
      // Update the scan point.
      Body = Body.substr(Pos);
    }
  
    return false;
  }
  
  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::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;
  };
  
  } // end anonymous namespace
  
  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;
  
    // Darwin doesn't use spaces to delmit arguments.
    AsmLexerSkipSpaceRAII ScopedSkipSpace(Lexer, IsDarwin);
  
    bool SpaceEaten;
  
    while (true) {
      SpaceEaten = false;
      if (Lexer.is(AsmToken::Eof) || Lexer.is(AsmToken::Equal))
        return TokError("unexpected token in macro instantiation");
  
      if (ParenLevel == 0) {
  
        if (Lexer.is(AsmToken::Comma))
          break;
  
        if (Lexer.is(AsmToken::Space)) {
          SpaceEaten = true;
          Lexer.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())) {
            MA.push_back(getTok());
            Lexer.Lex();
  
            // Whitespace after an operator can be ignored.
            if (Lexer.is(AsmToken::Space))
              Lexer.Lex();
  
            continue;
          }
        }
        if (SpaceEaten)
          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());
      Lexer.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))
          return Error(IDLoc, "invalid argument identifier for formal argument");
  
        if (Lexer.isNot(AsmToken::Equal))
          return TokError("expected '=' after formal parameter identifier");
  
        Lex();
  
        NamedParametersFound = true;
      }
      bool Vararg = HasVararg && Parameter == (NParameters - 1);
  
      if (NamedParametersFound && FA.Name.empty())
        return Error(IDLoc, "cannot mix positional and keyword arguments");
  
      SMLoc StrLoc = Lexer.getLoc();
      SMLoc EndLoc;
      if (AltMacroMode && Lexer.is(AsmToken::Percent)) {
        const MCExpr *AbsoluteExp;
        int64_t Value;
        /// Eat '%'
        Lex();
        if (parseExpression(AbsoluteExp, EndLoc))
          return false;
        if (!AbsoluteExp->evaluateAsAbsolute(Value,
                                             getStreamer().getAssemblerPtr()))
          return Error(StrLoc, "expected absolute expression");
        const char *StrChar = StrLoc.getPointer();
        const char *EndChar = EndLoc.getPointer();
        AsmToken newToken(AsmToken::Integer,
                          StringRef(StrChar, EndChar - StrChar), Value);
        FA.Value.push_back(newToken);
      } else if (AltMacroMode && Lexer.is(AsmToken::Less) &&
                 isAltmacroString(StrLoc, EndLoc)) {
        const char *StrChar = StrLoc.getPointer();
        const char *EndChar = EndLoc.getPointer();
        jumpToLoc(EndLoc, CurBuffer);
        /// Eat from '<' to '>'
        Lex();
        AsmToken newToken(AsmToken::String,
                          StringRef(StrChar, EndChar - StrChar));
        FA.Value.push_back(newToken);
      } else 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");
          return Error(IDLoc, "parameter named '" + FA.Name +
                                  "' does not exist for macro '" + M->Name + "'");
        }
        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");
  }
  
  bool AsmParser::handleMacroEntry(const MCAsmMacro *M, SMLoc NameLoc) {
    // Arbitrarily limit macro nesting depth (default matches 'as'). We can
    // eliminate this, although we should protect against infinite loops.
    unsigned MaxNestingDepth = AsmMacroMaxNestingDepth;
    if (ActiveMacros.size() == MaxNestingDepth) {
      std::ostringstream MaxNestingDepthError;
      MaxNestingDepthError << "macros cannot be nested more than "
                           << MaxNestingDepth << " levels deep."
                           << " Use -asm-macro-max-nesting-depth to increase "
                              "this limit.";
      return TokError(MaxNestingDepthError.str());
    }
  
    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.
  
      AsmToken Buf[1];
      Lexer.peekTokens(Buf, false);
  
      if (Buf[0].isNot(AsmToken::Identifier))
        return true;
  
      // We have a '$' or '@' followed by an identifier, make sure they are adjacent.
      if (PrefixLoc.getPointer() + 1 != Buf[0].getLoc().getPointer())
        return true;
  
      // eat $ or @
      Lexer.Lex(); // Lexer's Lex guarantees consecutive token.
      // Construct the joined identifier and consume the token.
      Res =
          StringRef(PrefixLoc.getPointer(), getTok().getIdentifier().size() + 1);
      Lex(); // Parser Lex to maintain invariants.
      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 (check(parseIdentifier(Name), "expected identifier") ||
        parseToken(AsmToken::Comma) || parseAssignment(Name, allow_redef, true))
      return addErrorSuffix(" in '" + Twine(IDVal) + "' directive");
    return false;
  }
  
  bool AsmParser::parseEscapedString(std::string &Data) {
    if (check(getTok().isNot(AsmToken::String), "expected string"))
      return true;
  
    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'.
      ++i;
      if (i == e)
        return TokError("unexpected backslash at end of string");
  
      // Recognize hex sequences similarly to GNU 'as'.
      if (Str[i] == 'x' || Str[i] == 'X') {
        size_t length = Str.size();
        if (i + 1 >= length || !isHexDigit(Str[i + 1]))
          return TokError("invalid hexadecimal escape sequence");
  
        // Consume hex characters. GNU 'as' reads all hexadecimal characters and
        // then truncates to the lower 16 bits. Seems reasonable.
        unsigned Value = 0;
        while (i + 1 < length && isHexDigit(Str[i + 1]))
          Value = Value * 16 + hexDigitValue(Str[++i]);
  
        Data += (unsigned char)(Value & 0xFF);
        continue;
      }
  
      // 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;
      }
    }
  
    Lex();
    return false;
  }
  
  /// parseDirectiveAscii:
  ///   ::= ( .ascii | .asciz | .string ) [ "string" ( , "string" )* ]
  bool AsmParser::parseDirectiveAscii(StringRef IDVal, bool ZeroTerminated) {
    auto parseOp = [&]() -> bool {
      std::string Data;
      if (checkForValidSection() || parseEscapedString(Data))
        return true;
      getStreamer().EmitBytes(Data);
      if (ZeroTerminated)
        getStreamer().EmitBytes(StringRef("\0", 1));
      return false;
    };
  
    if (parseMany(parseOp))
      return addErrorSuffix(" in '" + Twine(IDVal) + "' directive");
    return false;
  }
  
  /// parseDirectiveReloc
  ///  ::= .reloc expression , identifier [ , expression ]
  bool AsmParser::parseDirectiveReloc(SMLoc DirectiveLoc) {
    const MCExpr *Offset;
    const MCExpr *Expr = nullptr;
    int64_t OffsetValue;
    SMLoc OffsetLoc = Lexer.getTok().getLoc();
  
    if (parseExpression(Offset))
      return true;
  
    if ((Offset->evaluateAsAbsolute(OffsetValue,
                                    getStreamer().getAssemblerPtr()) &&
         check(OffsetValue < 0, OffsetLoc, "expression is negative")) ||
        (check(Offset->getKind() != llvm::MCExpr::Constant &&
               Offset->getKind() != llvm::MCExpr::SymbolRef,
               OffsetLoc, "expected non-negative number or a label")) ||
        (parseToken(AsmToken::Comma, "expected comma") ||
         check(getTok().isNot(AsmToken::Identifier), "expected relocation name")))
      return true;
  
    SMLoc NameLoc = Lexer.getTok().getLoc();
    StringRef Name = Lexer.getTok().getIdentifier();
    Lex();
  
    if (Lexer.is(AsmToken::Comma)) {
      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 (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in .reloc directive"))
        return true;
  
    const MCTargetAsmParser &MCT = getTargetParser();
    const MCSubtargetInfo &STI = MCT.getSTI();
    if (getStreamer().EmitRelocDirective(*Offset, Name, Expr, DirectiveLoc, STI))
      return Error(NameLoc, "unknown relocation name");
  
    return false;
  }
  
  /// parseDirectiveValue
  ///  ::= (.byte | .short | ... ) [ expression (, expression)* ]
  bool AsmParser::parseDirectiveValue(StringRef IDVal, unsigned Size) {
    auto parseOp = [&]() -> bool {
      const MCExpr *Value;
      SMLoc ExprLoc = getLexer().getLoc();
      if (checkForValidSection() || 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, "out of range literal value");
        getStreamer().EmitIntValue(IntValue, Size);
      } else
        getStreamer().EmitValue(Value, Size, ExprLoc);
      return false;
    };
  
    if (parseMany(parseOp))
      return addErrorSuffix(" in '" + Twine(IDVal) + "' directive");
    return false;
  }
  
  static bool parseHexOcta(AsmParser &Asm, uint64_t &hi, uint64_t &lo) {
    if (Asm.getTok().isNot(AsmToken::Integer) &&
        Asm.getTok().isNot(AsmToken::BigNum))
      return Asm.TokError("unknown token in expression");
    SMLoc ExprLoc = Asm.getTok().getLoc();
    APInt IntValue = Asm.getTok().getAPIntVal();
    Asm.Lex();
    if (!IntValue.isIntN(128))
      return Asm.Error(ExprLoc, "out of range literal value");
    if (!IntValue.isIntN(64)) {
      hi = IntValue.getHiBits(IntValue.getBitWidth() - 64).getZExtValue();
      lo = IntValue.getLoBits(64).getZExtValue();
    } else {
      hi = 0;
      lo = IntValue.getZExtValue();
    }
    return false;
  }
  
  /// ParseDirectiveOctaValue
  ///  ::= .octa [ hexconstant (, hexconstant)* ]
  
  bool AsmParser::parseDirectiveOctaValue(StringRef IDVal) {
    auto parseOp = [&]() -> bool {
      if (checkForValidSection())
        return true;
      uint64_t hi, lo;
      if (parseHexOcta(*this, hi, lo))
        return true;
      if (MAI.isLittleEndian()) {
        getStreamer().EmitIntValue(lo, 8);
        getStreamer().EmitIntValue(hi, 8);
      } else {
        getStreamer().EmitIntValue(hi, 8);
        getStreamer().EmitIntValue(lo, 8);
      }
      return false;
    };
  
    if (parseMany(parseOp))
      return addErrorSuffix(" in '" + Twine(IDVal) + "' directive");
    return false;
  }
  
  bool AsmParser::parseRealValue(const fltSemantics &Semantics, APInt &Res) {
    // 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)) {
      Lexer.Lex();
      IsNeg = true;
    } else if (getLexer().is(AsmToken::Plus))
      Lexer.Lex();
  
    if (Lexer.is(AsmToken::Error))
      return TokError(Lexer.getErr());
    if (Lexer.isNot(AsmToken::Integer) && Lexer.isNot(AsmToken::Real) &&
        Lexer.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();
  
    Res = Value.bitcastToAPInt();
  
    return false;
  }
  
  /// parseDirectiveRealValue
  ///  ::= (.single | .double) [ expression (, expression)* ]
  bool AsmParser::parseDirectiveRealValue(StringRef IDVal,
                                          const fltSemantics &Semantics) {
    auto parseOp = [&]() -> bool {
      APInt AsInt;
      if (checkForValidSection() || parseRealValue(Semantics, AsInt))
        return true;
      getStreamer().EmitIntValue(AsInt.getLimitedValue(),
                                 AsInt.getBitWidth() / 8);
      return false;
    };
  
    if (parseMany(parseOp))
      return addErrorSuffix(" in '" + Twine(IDVal) + "' directive");
    return false;
  }
  
  /// parseDirectiveZero
  ///  ::= .zero expression
  bool AsmParser::parseDirectiveZero() {
    SMLoc NumBytesLoc = Lexer.getLoc();
    const MCExpr *NumBytes;
    if (checkForValidSection() || parseExpression(NumBytes))
      return true;
  
    int64_t Val = 0;
    if (getLexer().is(AsmToken::Comma)) {
      Lex();
      if (parseAbsoluteExpression(Val))
        return true;
    }
  
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.zero' directive"))
      return true;
    getStreamer().emitFill(*NumBytes, Val, NumBytesLoc);
  
    return false;
  }
  
  /// parseDirectiveFill
  ///  ::= .fill expression [ , expression [ , expression ] ]
  bool AsmParser::parseDirectiveFill() {
    SMLoc NumValuesLoc = Lexer.getLoc();
    const MCExpr *NumValues;
    if (checkForValidSection() || parseExpression(NumValues))
      return true;
  
    int64_t FillSize = 1;
    int64_t FillExpr = 0;
  
    SMLoc SizeLoc, ExprLoc;
  
    if (parseOptionalToken(AsmToken::Comma)) {
      SizeLoc = getTok().getLoc();
      if (parseAbsoluteExpression(FillSize))
        return true;
      if (parseOptionalToken(AsmToken::Comma)) {
        ExprLoc = getTok().getLoc();
        if (parseAbsoluteExpression(FillExpr))
          return true;
      }
    }
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.fill' directive"))
      return true;
  
    if (FillSize < 0) {
      Warning(SizeLoc, "'.fill' directive with negative size has no effect");
      return false;
    }
    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");
  
    getStreamer().emitFill(*NumValues, FillSize, FillExpr, NumValuesLoc);
  
    return false;
  }
  
  /// parseDirectiveOrg
  ///  ::= .org expression [ , expression ]
  bool AsmParser::parseDirectiveOrg() {
    const MCExpr *Offset;
    SMLoc OffsetLoc = Lexer.getLoc();
    if (checkForValidSection() || parseExpression(Offset))
      return true;
  
    // Parse optional fill expression.
    int64_t FillExpr = 0;
    if (parseOptionalToken(AsmToken::Comma))
      if (parseAbsoluteExpression(FillExpr))
        return addErrorSuffix(" in '.org' directive");
    if (parseToken(AsmToken::EndOfStatement))
      return addErrorSuffix(" in '.org' directive");
  
    getStreamer().emitValueToOffset(Offset, FillExpr, OffsetLoc);
    return false;
  }
  
  /// parseDirectiveAlign
  ///  ::= {.align, ...} expression [ , expression [ , expression ]]
  bool AsmParser::parseDirectiveAlign(bool IsPow2, unsigned ValueSize) {
    SMLoc AlignmentLoc = getLexer().getLoc();
    int64_t Alignment;
    SMLoc MaxBytesLoc;
    bool HasFillExpr = false;
    int64_t FillExpr = 0;
    int64_t MaxBytesToFill = 0;
  
    auto parseAlign = [&]() -> bool {
      if (parseAbsoluteExpression(Alignment))
        return true;
      if (parseOptionalToken(AsmToken::Comma)) {
        // The fill expression can be omitted while specifying a maximum number of
        // alignment bytes, e.g:
        //  .align 3,,4
        if (getTok().isNot(AsmToken::Comma)) {
          HasFillExpr = true;
          if (parseAbsoluteExpression(FillExpr))
            return true;
        }
        if (parseOptionalToken(AsmToken::Comma))
          if (parseTokenLoc(MaxBytesLoc) ||
              parseAbsoluteExpression(MaxBytesToFill))
            return true;
      }
      return parseToken(AsmToken::EndOfStatement);
    };
  
    if (checkForValidSection())
      return addErrorSuffix(" in directive");
    // Ignore empty '.p2align' directives for GNU-as compatibility
    if (IsPow2 && (ValueSize == 1) && getTok().is(AsmToken::EndOfStatement)) {
      Warning(AlignmentLoc, "p2align directive with no operand(s) is ignored");
      return parseToken(AsmToken::EndOfStatement);
    }
    if (parseAlign())
      return addErrorSuffix(" in directive");
  
    // Always emit an alignment here even if we thrown an error.
    bool ReturnVal = false;
  
    // Compute alignment in bytes.
    if (IsPow2) {
      // FIXME: Diagnose overflow.
      if (Alignment >= 32) {
        ReturnVal |= 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))
        ReturnVal |= Error(AlignmentLoc, "alignment must be a power of 2");
    }
  
    // Diagnose non-sensical max bytes to align.
    if (MaxBytesLoc.isValid()) {
      if (MaxBytesToFill < 1) {
        ReturnVal |= 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().getCurrentSectionOnly();
    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 ReturnVal;
  }
  
  /// parseDirectiveFile
  /// ::= .file filename
  /// ::= .file number [directory] filename [md5 checksum] [source source-text]
  bool AsmParser::parseDirectiveFile(SMLoc DirectiveLoc) {
    // FIXME: I'm not sure what this is.
    int64_t FileNumber = -1;
    if (getLexer().is(AsmToken::Integer)) {
      FileNumber = getTok().getIntVal();
      Lex();
  
      if (FileNumber < 0)
        return TokError("negative file number");
    }
  
    std::string Path;
  
    // Usually the directory and filename together, otherwise just the directory.
    // Allow the strings to have escaped octal character sequence.
    if (check(getTok().isNot(AsmToken::String),
              "unexpected token in '.file' directive") ||
        parseEscapedString(Path))
      return true;
  
    StringRef Directory;
    StringRef Filename;
    std::string FilenameData;
    if (getLexer().is(AsmToken::String)) {
      if (check(FileNumber == -1,
                "explicit path specified, but no file number") ||
          parseEscapedString(FilenameData))
        return true;
      Filename = FilenameData;
      Directory = Path;
    } else {
      Filename = Path;
    }
  
    uint64_t MD5Hi, MD5Lo;
    bool HasMD5 = false;
  
    Optional<StringRef> Source;
    bool HasSource = false;
    std::string SourceString;
  
    while (!parseOptionalToken(AsmToken::EndOfStatement)) {
      StringRef Keyword;
      if (check(getTok().isNot(AsmToken::Identifier),
                "unexpected token in '.file' directive") ||
          parseIdentifier(Keyword))
        return true;
      if (Keyword == "md5") {
        HasMD5 = true;
        if (check(FileNumber == -1,
                  "MD5 checksum specified, but no file number") ||
            parseHexOcta(*this, MD5Hi, MD5Lo))
          return true;
      } else if (Keyword == "source") {
        HasSource = true;
        if (check(FileNumber == -1,
                  "source specified, but no file number") ||
            check(getTok().isNot(AsmToken::String),
                  "unexpected token in '.file' directive") ||
            parseEscapedString(SourceString))
          return true;
      } else {
        return TokError("unexpected token in '.file' directive");
      }
    }
  
    if (FileNumber == -1) {
      // Ignore the directive if there is no number and the target doesn't support
      // numberless .file directives. This allows some portability of assembler
      // between different object file formats.
      if (getContext().getAsmInfo()->hasSingleParameterDotFile())
        getStreamer().EmitFileDirective(Filename);
    } else {
      // In case there is a -g option as well as debug info from directive .file,
      // we turn off the -g option, directly use the existing debug info instead.
      // Throw away any implicit file table for the assembler source.
      if (Ctx.getGenDwarfForAssembly()) {
        Ctx.getMCDwarfLineTable(0).resetFileTable();
        Ctx.setGenDwarfForAssembly(false);
      }
  
      Optional<MD5::MD5Result> CKMem;
      if (HasMD5) {
        MD5::MD5Result Sum;
        for (unsigned i = 0; i != 8; ++i) {
          Sum.Bytes[i] = uint8_t(MD5Hi >> ((7 - i) * 8));
          Sum.Bytes[i + 8] = uint8_t(MD5Lo >> ((7 - i) * 8));
        }
        CKMem = Sum;
      }
      if (HasSource) {
        char *SourceBuf = static_cast<char *>(Ctx.allocate(SourceString.size()));
        memcpy(SourceBuf, SourceString.data(), SourceString.size());
        Source = StringRef(SourceBuf, SourceString.size());
      }
      if (FileNumber == 0) {
        if (Ctx.getDwarfVersion() < 5)
          return Warning(DirectiveLoc, "file 0 not supported prior to DWARF-5");
        getStreamer().emitDwarfFile0Directive(Directory, Filename, CKMem, Source);
      } else {
        Expected<unsigned> FileNumOrErr = getStreamer().tryEmitDwarfFileDirective(
            FileNumber, Directory, Filename, CKMem, Source);
        if (!FileNumOrErr)
          return Error(DirectiveLoc, toString(FileNumOrErr.takeError()));
      }
      // Alert the user if there are some .file directives with MD5 and some not.
      // But only do that once.
      if (!ReportedInconsistentMD5 && !Ctx.isDwarfMD5UsageConsistent(0)) {
        ReportedInconsistentMD5 = true;
        return Warning(DirectiveLoc, "inconsistent use of MD5 checksums");
      }
    }
  
    return false;
  }
  
  /// parseDirectiveLine
  /// ::= .line [number]
  bool AsmParser::parseDirectiveLine() {
    int64_t LineNumber;
    if (getLexer().is(AsmToken::Integer)) {
      if (parseIntToken(LineNumber, "unexpected token in '.line' directive"))
        return true;
      (void)LineNumber;
      // FIXME: Do something with the .line.
    }
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.line' directive"))
      return true;
  
    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() {
    int64_t FileNumber = 0, LineNumber = 0;
    SMLoc Loc = getTok().getLoc();
    if (parseIntToken(FileNumber, "unexpected token in '.loc' directive") ||
        check(FileNumber < 1 && Ctx.getDwarfVersion() < 5, Loc,
              "file number less than one in '.loc' directive") ||
        check(!getContext().isValidDwarfFileNumber(FileNumber), Loc,
              "unassigned file number in '.loc' directive"))
      return true;
  
    // optional
    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;
  
    auto parseLocOp = [&]() -> bool {
      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");
      }
      return false;
    };
  
    if (parseMany(parseLocOp, false /*hasComma*/))
      return true;
  
    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 [checksum] [checksumkind]
  bool AsmParser::parseDirectiveCVFile() {
    SMLoc FileNumberLoc = getTok().getLoc();
    int64_t FileNumber;
    std::string Filename;
    std::string Checksum;
    int64_t ChecksumKind = 0;
  
    if (parseIntToken(FileNumber,
                      "expected file number in '.cv_file' directive") ||
        check(FileNumber < 1, FileNumberLoc, "file number less than one") ||
        check(getTok().isNot(AsmToken::String),
              "unexpected token in '.cv_file' directive") ||
        parseEscapedString(Filename))
      return true;
    if (!parseOptionalToken(AsmToken::EndOfStatement)) {
      if (check(getTok().isNot(AsmToken::String),
                "unexpected token in '.cv_file' directive") ||
          parseEscapedString(Checksum) ||
          parseIntToken(ChecksumKind,
                        "expected checksum kind in '.cv_file' directive") ||
          parseToken(AsmToken::EndOfStatement,
                     "unexpected token in '.cv_file' directive"))
        return true;
    }
  
    Checksum = fromHex(Checksum);
    void *CKMem = Ctx.allocate(Checksum.size(), 1);
    memcpy(CKMem, Checksum.data(), Checksum.size());
    ArrayRef<uint8_t> ChecksumAsBytes(reinterpret_cast<const uint8_t *>(CKMem),
                                      Checksum.size());
  
    if (!getStreamer().EmitCVFileDirective(FileNumber, Filename, ChecksumAsBytes,
                                           static_cast<uint8_t>(ChecksumKind)))
      return Error(FileNumberLoc, "file number already allocated");
  
    return false;
  }
  
  bool AsmParser::parseCVFunctionId(int64_t &FunctionId,
                                    StringRef DirectiveName) {
    SMLoc Loc;
    return parseTokenLoc(Loc) ||
           parseIntToken(FunctionId, "expected function id in '" + DirectiveName +
                                         "' directive") ||
           check(FunctionId < 0 || FunctionId >= UINT_MAX, Loc,
                 "expected function id within range [0, UINT_MAX)");
  }
  
  bool AsmParser::parseCVFileId(int64_t &FileNumber, StringRef DirectiveName) {
    SMLoc Loc;
    return parseTokenLoc(Loc) ||
           parseIntToken(FileNumber, "expected integer in '" + DirectiveName +
                                         "' directive") ||
           check(FileNumber < 1, Loc, "file number less than one in '" +
                                          DirectiveName + "' directive") ||
           check(!getCVContext().isValidFileNumber(FileNumber), Loc,
                 "unassigned file number in '" + DirectiveName + "' directive");
  }
  
  /// parseDirectiveCVFuncId
  /// ::= .cv_func_id FunctionId
  ///
  /// Introduces a function ID that can be used with .cv_loc.
  bool AsmParser::parseDirectiveCVFuncId() {
    SMLoc FunctionIdLoc = getTok().getLoc();
    int64_t FunctionId;
  
    if (parseCVFunctionId(FunctionId, ".cv_func_id") ||
        parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.cv_func_id' directive"))
      return true;
  
    if (!getStreamer().EmitCVFuncIdDirective(FunctionId))
      return Error(FunctionIdLoc, "function id already allocated");
  
    return false;
  }
  
  /// parseDirectiveCVInlineSiteId
  /// ::= .cv_inline_site_id FunctionId
  ///         "within" IAFunc
  ///         "inlined_at" IAFile IALine [IACol]
  ///
  /// Introduces a function ID that can be used with .cv_loc. Includes "inlined
  /// at" source location information for use in the line table of the caller,
  /// whether the caller is a real function or another inlined call site.
  bool AsmParser::parseDirectiveCVInlineSiteId() {
    SMLoc FunctionIdLoc = getTok().getLoc();
    int64_t FunctionId;
    int64_t IAFunc;
    int64_t IAFile;
    int64_t IALine;
    int64_t IACol = 0;
  
    // FunctionId
    if (parseCVFunctionId(FunctionId, ".cv_inline_site_id"))
      return true;
  
    // "within"
    if (check((getLexer().isNot(AsmToken::Identifier) ||
               getTok().getIdentifier() != "within"),
              "expected 'within' identifier in '.cv_inline_site_id' directive"))
      return true;
    Lex();
  
    // IAFunc
    if (parseCVFunctionId(IAFunc, ".cv_inline_site_id"))
      return true;
  
    // "inlined_at"
    if (check((getLexer().isNot(AsmToken::Identifier) ||
               getTok().getIdentifier() != "inlined_at"),
              "expected 'inlined_at' identifier in '.cv_inline_site_id' "
              "directive") )
      return true;
    Lex();
  
    // IAFile IALine
    if (parseCVFileId(IAFile, ".cv_inline_site_id") ||
        parseIntToken(IALine, "expected line number after 'inlined_at'"))
      return true;
  
    // [IACol]
    if (getLexer().is(AsmToken::Integer)) {
      IACol = getTok().getIntVal();
      Lex();
    }
  
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.cv_inline_site_id' directive"))
      return true;
  
    if (!getStreamer().EmitCVInlineSiteIdDirective(FunctionId, IAFunc, IAFile,
                                                   IALine, IACol, FunctionIdLoc))
      return Error(FunctionIdLoc, "function id 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() {
    SMLoc DirectiveLoc = getTok().getLoc();
    int64_t FunctionId, FileNumber;
    if (parseCVFunctionId(FunctionId, ".cv_loc") ||
        parseCVFileId(FileNumber, ".cv_loc"))
      return true;
  
    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;
  
    auto parseOp = [&]() -> bool {
      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");
      }
      return false;
    };
  
    if (parseMany(parseOp, false /*hasComma*/))
      return true;
  
    getStreamer().EmitCVLocDirective(FunctionId, FileNumber, LineNumber,
                                     ColumnPos, PrologueEnd, IsStmt, StringRef(),
                                     DirectiveLoc);
    return false;
  }
  
  /// parseDirectiveCVLinetable
  /// ::= .cv_linetable FunctionId, FnStart, FnEnd
  bool AsmParser::parseDirectiveCVLinetable() {
    int64_t FunctionId;
    StringRef FnStartName, FnEndName;
    SMLoc Loc = getTok().getLoc();
    if (parseCVFunctionId(FunctionId, ".cv_linetable") ||
        parseToken(AsmToken::Comma,
                   "unexpected token in '.cv_linetable' directive") ||
        parseTokenLoc(Loc) || check(parseIdentifier(FnStartName), Loc,
                                    "expected identifier in directive") ||
        parseToken(AsmToken::Comma,
                   "unexpected token in '.cv_linetable' directive") ||
        parseTokenLoc(Loc) || check(parseIdentifier(FnEndName), Loc,
                                    "expected identifier in directive"))
      return true;
  
    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
  bool AsmParser::parseDirectiveCVInlineLinetable() {
    int64_t PrimaryFunctionId, SourceFileId, SourceLineNum;
    StringRef FnStartName, FnEndName;
    SMLoc Loc = getTok().getLoc();
    if (parseCVFunctionId(PrimaryFunctionId, ".cv_inline_linetable") ||
        parseTokenLoc(Loc) ||
        parseIntToken(
            SourceFileId,
            "expected SourceField in '.cv_inline_linetable' directive") ||
        check(SourceFileId <= 0, Loc,
              "File id less than zero in '.cv_inline_linetable' directive") ||
        parseTokenLoc(Loc) ||
        parseIntToken(
            SourceLineNum,
            "expected SourceLineNum in '.cv_inline_linetable' directive") ||
        check(SourceLineNum < 0, Loc,
              "Line number less than zero in '.cv_inline_linetable' directive") ||
        parseTokenLoc(Loc) || check(parseIdentifier(FnStartName), Loc,
                                    "expected identifier in directive") ||
        parseTokenLoc(Loc) || check(parseIdentifier(FnEndName), Loc,
                                    "expected identifier in directive"))
      return true;
  
    if (parseToken(AsmToken::EndOfStatement, "Expected End of Statement"))
      return true;
  
    MCSymbol *FnStartSym = getContext().getOrCreateSymbol(FnStartName);
    MCSymbol *FnEndSym = getContext().getOrCreateSymbol(FnEndName);
    getStreamer().EmitCVInlineLinetableDirective(PrimaryFunctionId, SourceFileId,
                                                 SourceLineNum, FnStartSym,
                                                 FnEndSym);
    return false;
  }
  
  void AsmParser::initializeCVDefRangeTypeMap() {
    CVDefRangeTypeMap["reg"] = CVDR_DEFRANGE_REGISTER;
    CVDefRangeTypeMap["frame_ptr_rel"] = CVDR_DEFRANGE_FRAMEPOINTER_REL;
    CVDefRangeTypeMap["subfield_reg"] = CVDR_DEFRANGE_SUBFIELD_REGISTER;
    CVDefRangeTypeMap["reg_rel"] = CVDR_DEFRANGE_REGISTER_REL;
  }
  
  /// parseDirectiveCVDefRange
  /// ::= .cv_def_range RangeStart RangeEnd (GapStart GapEnd)*, bytes*
  bool AsmParser::parseDirectiveCVDefRange() {
    SMLoc Loc;
    std::vector<std::pair<const MCSymbol *, const MCSymbol *>> Ranges;
    while (getLexer().is(AsmToken::Identifier)) {
      Loc = getLexer().getLoc();
      StringRef GapStartName;
      if (parseIdentifier(GapStartName))
        return Error(Loc, "expected identifier in directive");
      MCSymbol *GapStartSym = getContext().getOrCreateSymbol(GapStartName);
  
      Loc = getLexer().getLoc();
      StringRef GapEndName;
      if (parseIdentifier(GapEndName))
        return Error(Loc, "expected identifier in directive");
      MCSymbol *GapEndSym = getContext().getOrCreateSymbol(GapEndName);
  
      Ranges.push_back({GapStartSym, GapEndSym});
    }
  
    StringRef CVDefRangeTypeStr;
    if (parseToken(
            AsmToken::Comma,
            "expected comma before def_range type in .cv_def_range directive") ||
        parseIdentifier(CVDefRangeTypeStr))
      return Error(Loc, "expected def_range type in directive");
  
    StringMap<CVDefRangeType>::const_iterator CVTypeIt =
        CVDefRangeTypeMap.find(CVDefRangeTypeStr);
    CVDefRangeType CVDRType = (CVTypeIt == CVDefRangeTypeMap.end())
                                  ? CVDR_DEFRANGE
                                  : CVTypeIt->getValue();
    switch (CVDRType) {
    case CVDR_DEFRANGE_REGISTER: {
      int64_t DRRegister;
      if (parseToken(AsmToken::Comma, "expected comma before register number in "
                                      ".cv_def_range directive") ||
          parseAbsoluteExpression(DRRegister))
        return Error(Loc, "expected register number");
  
      codeview::DefRangeRegisterHeader DRHdr;
      DRHdr.Register = DRRegister;
      DRHdr.MayHaveNoName = 0;
      getStreamer().EmitCVDefRangeDirective(Ranges, DRHdr);
      break;
    }
    case CVDR_DEFRANGE_FRAMEPOINTER_REL: {
      int64_t DROffset;
      if (parseToken(AsmToken::Comma,
                     "expected comma before offset in .cv_def_range directive") ||
          parseAbsoluteExpression(DROffset))
        return Error(Loc, "expected offset value");
  
      codeview::DefRangeFramePointerRelHeader DRHdr;
      DRHdr.Offset = DROffset;
      getStreamer().EmitCVDefRangeDirective(Ranges, DRHdr);
      break;
    }
    case CVDR_DEFRANGE_SUBFIELD_REGISTER: {
      int64_t DRRegister;
      int64_t DROffsetInParent;
      if (parseToken(AsmToken::Comma, "expected comma before register number in "
                                      ".cv_def_range directive") ||
          parseAbsoluteExpression(DRRegister))
        return Error(Loc, "expected register number");
      if (parseToken(AsmToken::Comma,
                     "expected comma before offset in .cv_def_range directive") ||
          parseAbsoluteExpression(DROffsetInParent))
        return Error(Loc, "expected offset value");
  
      codeview::DefRangeSubfieldRegisterHeader DRHdr;
      DRHdr.Register = DRRegister;
      DRHdr.MayHaveNoName = 0;
      DRHdr.OffsetInParent = DROffsetInParent;
      getStreamer().EmitCVDefRangeDirective(Ranges, DRHdr);
      break;
    }
    case CVDR_DEFRANGE_REGISTER_REL: {
      int64_t DRRegister;
      int64_t DRFlags;
      int64_t DRBasePointerOffset;
      if (parseToken(AsmToken::Comma, "expected comma before register number in "
                                      ".cv_def_range directive") ||
          parseAbsoluteExpression(DRRegister))
        return Error(Loc, "expected register value");
      if (parseToken(
              AsmToken::Comma,
              "expected comma before flag value in .cv_def_range directive") ||
          parseAbsoluteExpression(DRFlags))
        return Error(Loc, "expected flag value");
      if (parseToken(AsmToken::Comma, "expected comma before base pointer offset "
                                      "in .cv_def_range directive") ||
          parseAbsoluteExpression(DRBasePointerOffset))
        return Error(Loc, "expected base pointer offset value");
  
      codeview::DefRangeRegisterRelHeader DRHdr;
      DRHdr.Register = DRRegister;
      DRHdr.Flags = DRFlags;
      DRHdr.BasePointerOffset = DRBasePointerOffset;
      getStreamer().EmitCVDefRangeDirective(Ranges, DRHdr);
      break;
    }
    default:
      return Error(Loc, "unexpected def_range type in .cv_def_range directive");
    }
    return true;
  }
  
  /// parseDirectiveCVString
  /// ::= .cv_stringtable "string"
  bool AsmParser::parseDirectiveCVString() {
    std::string Data;
    if (checkForValidSection() || parseEscapedString(Data))
      return addErrorSuffix(" in '.cv_string' directive");
  
    // Put the string in the table and emit the offset.
    std::pair<StringRef, unsigned> Insertion =
        getCVContext().addToStringTable(Data);
    getStreamer().EmitIntValue(Insertion.second, 4);
    return false;
  }
  
  /// parseDirectiveCVStringTable
  /// ::= .cv_stringtable
  bool AsmParser::parseDirectiveCVStringTable() {
    getStreamer().EmitCVStringTableDirective();
    return false;
  }
  
  /// parseDirectiveCVFileChecksums
  /// ::= .cv_filechecksums
  bool AsmParser::parseDirectiveCVFileChecksums() {
    getStreamer().EmitCVFileChecksumsDirective();
    return false;
  }
  
  /// parseDirectiveCVFileChecksumOffset
  /// ::= .cv_filechecksumoffset fileno
  bool AsmParser::parseDirectiveCVFileChecksumOffset() {
    int64_t FileNo;
    if (parseIntToken(FileNo, "expected identifier in directive"))
      return true;
    if (parseToken(AsmToken::EndOfStatement, "Expected End of Statement"))
      return true;
    getStreamer().EmitCVFileChecksumOffsetDirective(FileNo);
    return false;
  }
  
  /// parseDirectiveCVFPOData
  /// ::= .cv_fpo_data procsym
  bool AsmParser::parseDirectiveCVFPOData() {
    SMLoc DirLoc = getLexer().getLoc();
    StringRef ProcName;
    if (parseIdentifier(ProcName))
      return TokError("expected symbol name");
    if (parseEOL("unexpected tokens"))
      return addErrorSuffix(" in '.cv_fpo_data' directive");
    MCSymbol *ProcSym = getContext().getOrCreateSymbol(ProcName);
    getStreamer().EmitCVFPOData(ProcSym, DirLoc);
    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 (!parseOptionalToken(AsmToken::EndOfStatement)) {
      if (check(parseIdentifier(Simple) || Simple != "simple",
                "unexpected token") ||
          parseToken(AsmToken::EndOfStatement))
        return addErrorSuffix(" in '.cfi_startproc' directive");
    }
  
    // TODO(kristina): Deal with a corner case of incorrect diagnostic context
    // being produced if this directive is emitted as part of preprocessor macro
    // expansion which can *ONLY* happen if Clang's cc1as is the API consumer.
    // Tools like llvm-mc on the other hand are not affected by it, and report
    // correct context information.
    getStreamer().EmitCFIStartProc(!Simple.empty(), Lexer.getLoc());
    return false;
  }
  
  /// parseDirectiveCFIEndProc
  /// ::= .cfi_endproc
  bool AsmParser::parseDirectiveCFIEndProc() {
    getStreamer().EmitCFIEndProc();
    return false;
  }
  
  /// 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, Offset = 0;
    if (parseRegisterOrRegisterNumber(Register, DirectiveLoc) ||
        parseToken(AsmToken::Comma, "unexpected token in directive") ||
        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, Register2 = 0;
    if (parseRegisterOrRegisterNumber(Register1, DirectiveLoc) ||
        parseToken(AsmToken::Comma, "unexpected token in directive") ||
        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) ||
        parseToken(AsmToken::Comma, "unexpected token in directive") ||
        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, Offset = 0;
  
    if (parseRegisterOrRegisterNumber(Register, DirectiveLoc) ||
        parseToken(AsmToken::Comma, "unexpected token in directive") ||
        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;
  
    StringRef Name;
    if (check(!isValidEncoding(Encoding), "unsupported encoding.") ||
        parseToken(AsmToken::Comma, "unexpected token in directive") ||
        check(parseIdentifier(Name), "expected identifier in directive"))
      return true;
  
    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;
  }
  
  /// parseDirectiveCFIReturnColumn
  /// ::= .cfi_return_column register
  bool AsmParser::parseDirectiveCFIReturnColumn(SMLoc DirectiveLoc) {
    int64_t Register = 0;
    if (parseRegisterOrRegisterNumber(Register, DirectiveLoc))
      return true;
    getStreamer().EmitCFIReturnColumn(Register);
    return false;
  }
  
  /// parseDirectiveCFISignalFrame
  /// ::= .cfi_signal_frame
  bool AsmParser::parseDirectiveCFISignalFrame() {
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.cfi_signal_frame'"))
      return true;
  
    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;
  }
  
  /// parseDirectiveAltmacro
  /// ::= .altmacro
  /// ::= .noaltmacro
  bool AsmParser::parseDirectiveAltmacro(StringRef Directive) {
    if (getLexer().isNot(AsmToken::EndOfStatement))
      return TokError("unexpected token in '" + Directive + "' directive");
    AltMacroMode = (Directive == ".altmacro");
    return false;
  }
  
  /// parseDirectiveMacrosOnOff
  /// ::= .macros_on
  /// ::= .macros_off
  bool AsmParser::parseDirectiveMacrosOnOff(StringRef Directive) {
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '" + Directive + "' directive"))
      return true;
  
    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");
  
      // Emit an error if two (or more) named parameters share the same name
      for (const MCAsmMacroParameter& CurrParam : Parameters)
        if (CurrParam.Name.equals(Parameter.Name))
          return TokError("macro '" + Name + "' has multiple parameters"
                          " named '" + Parameter.Name + "'");
  
      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 just the end of statement.
    Lexer.Lex();
  
    // Consuming deferred text, so use Lexer.Lex to ignore Lexing Errors
    AsmToken EndToken, StartToken = getTok();
    unsigned MacroDepth = 0;
    // Lex the macro definition.
    while (true) {
      // Ignore Lexing errors in macros.
      while (Lexer.is(AsmToken::Error)) {
        Lexer.Lex();
      }
  
      // 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();
            Lexer.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 (getContext().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);
    MCAsmMacro Macro(Name, Body, std::move(Parameters));
    DEBUG_WITH_TYPE("asm-macros", dbgs() << "Defining new macro:\n";
                    Macro.dump());
    getContext().defineMacro(Name, std::move(Macro));
    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 (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '" + Directive + "' directive"))
      return true;
  
    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;
    SMLoc Loc;
    if (parseTokenLoc(Loc) ||
        check(parseIdentifier(Name), Loc,
              "expected identifier in '.purgem' directive") ||
        parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.purgem' directive"))
      return true;
  
    if (!getContext().lookupMacro(Name))
      return Error(DirectiveLoc, "macro '" + Name + "' is not defined");
  
    getContext().undefineMacro(Name);
    DEBUG_WITH_TYPE("asm-macros", dbgs()
                                      << "Un-defining macro: " << Name << "\n");
    return false;
  }
  
  /// parseDirectiveBundleAlignMode
  /// ::= {.bundle_align_mode} expression
  bool AsmParser::parseDirectiveBundleAlignMode() {
    // 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 (checkForValidSection() || parseAbsoluteExpression(AlignSizePow2) ||
        parseToken(AsmToken::EndOfStatement, "unexpected token after expression "
                                             "in '.bundle_align_mode' "
                                             "directive") ||
        check(AlignSizePow2 < 0 || AlignSizePow2 > 30, ExprLoc,
              "invalid bundle alignment size (expected between 0 and 30)"))
      return true;
  
    // 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() {
    if (checkForValidSection())
      return true;
    bool AlignToEnd = false;
  
    StringRef Option;
    SMLoc Loc = getTok().getLoc();
    const char *kInvalidOptionError =
        "invalid option for '.bundle_lock' directive";
  
    if (!parseOptionalToken(AsmToken::EndOfStatement)) {
      if (check(parseIdentifier(Option), Loc, kInvalidOptionError) ||
          check(Option != "align_to_end", Loc, kInvalidOptionError) ||
          parseToken(AsmToken::EndOfStatement,
                     "unexpected token after '.bundle_lock' directive option"))
        return true;
      AlignToEnd = true;
    }
  
    getStreamer().EmitBundleLock(AlignToEnd);
    return false;
  }
  
  /// parseDirectiveBundleLock
  /// ::= {.bundle_lock}
  bool AsmParser::parseDirectiveBundleUnlock() {
    if (checkForValidSection() ||
        parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.bundle_unlock' directive"))
      return true;
  
    getStreamer().EmitBundleUnlock();
    return false;
  }
  
  /// parseDirectiveSpace
  /// ::= (.skip | .space) expression [ , expression ]
  bool AsmParser::parseDirectiveSpace(StringRef IDVal) {
    SMLoc NumBytesLoc = Lexer.getLoc();
    const MCExpr *NumBytes;
    if (checkForValidSection() || parseExpression(NumBytes))
      return true;
  
    int64_t FillExpr = 0;
    if (parseOptionalToken(AsmToken::Comma))
      if (parseAbsoluteExpression(FillExpr))
        return addErrorSuffix("in '" + Twine(IDVal) + "' directive");
    if (parseToken(AsmToken::EndOfStatement))
      return addErrorSuffix("in '" + Twine(IDVal) + "' directive");
  
    // FIXME: Sometimes the fill expr is 'nop' if it isn't supplied, instead of 0.
    getStreamer().emitFill(*NumBytes, FillExpr, NumBytesLoc);
  
    return false;
  }
  
  /// parseDirectiveDCB
  /// ::= .dcb.{b, l, w} expression, expression
  bool AsmParser::parseDirectiveDCB(StringRef IDVal, unsigned Size) {
    SMLoc NumValuesLoc = Lexer.getLoc();
    int64_t NumValues;
    if (checkForValidSection() || parseAbsoluteExpression(NumValues))
      return true;
  
    if (NumValues < 0) {
      Warning(NumValuesLoc, "'" + Twine(IDVal) + "' directive with negative repeat count has no effect");
      return false;
    }
  
    if (parseToken(AsmToken::Comma,
                   "unexpected token in '" + Twine(IDVal) + "' directive"))
      return true;
  
    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");
      for (uint64_t i = 0, e = NumValues; i != e; ++i)
        getStreamer().EmitIntValue(IntValue, Size);
    } else {
      for (uint64_t i = 0, e = NumValues; i != e; ++i)
        getStreamer().EmitValue(Value, Size, ExprLoc);
    }
  
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '" + Twine(IDVal) + "' directive"))
      return true;
  
    return false;
  }
  
  /// parseDirectiveRealDCB
  /// ::= .dcb.{d, s} expression, expression
  bool AsmParser::parseDirectiveRealDCB(StringRef IDVal, const fltSemantics &Semantics) {
    SMLoc NumValuesLoc = Lexer.getLoc();
    int64_t NumValues;
    if (checkForValidSection() || parseAbsoluteExpression(NumValues))
      return true;
  
    if (NumValues < 0) {
      Warning(NumValuesLoc, "'" + Twine(IDVal) + "' directive with negative repeat count has no effect");
      return false;
    }
  
    if (parseToken(AsmToken::Comma,
                   "unexpected token in '" + Twine(IDVal) + "' directive"))
      return true;
  
    APInt AsInt;
    if (parseRealValue(Semantics, AsInt))
      return true;
  
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '" + Twine(IDVal) + "' directive"))
      return true;
  
    for (uint64_t i = 0, e = NumValues; i != e; ++i)
      getStreamer().EmitIntValue(AsInt.getLimitedValue(),
                                 AsInt.getBitWidth() / 8);
  
    return false;
  }
  
  /// parseDirectiveDS
  /// ::= .ds.{b, d, l, p, s, w, x} expression
  bool AsmParser::parseDirectiveDS(StringRef IDVal, unsigned Size) {
    SMLoc NumValuesLoc = Lexer.getLoc();
    int64_t NumValues;
    if (checkForValidSection() || parseAbsoluteExpression(NumValues))
      return true;
  
    if (NumValues < 0) {
      Warning(NumValuesLoc, "'" + Twine(IDVal) + "' directive with negative repeat count has no effect");
      return false;
    }
  
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '" + Twine(IDVal) + "' directive"))
      return true;
  
    for (uint64_t i = 0, e = NumValues; i != e; ++i)
      getStreamer().emitFill(Size, 0);
  
    return false;
  }
  
  /// parseDirectiveLEB128
  /// ::= (.sleb128 | .uleb128) [ expression (, expression)* ]
  bool AsmParser::parseDirectiveLEB128(bool Signed) {
    if (checkForValidSection())
      return true;
  
    auto parseOp = [&]() -> bool {
      const MCExpr *Value;
      if (parseExpression(Value))
        return true;
      if (Signed)
        getStreamer().EmitSLEB128Value(Value);
      else
        getStreamer().EmitULEB128Value(Value);
      return false;
    };
  
    if (parseMany(parseOp))
      return addErrorSuffix(" in directive");
  
    return false;
  }
  
  /// parseDirectiveSymbolAttribute
  ///  ::= { ".globl", ".weak", ... } [ identifier ( , identifier )* ]
  bool AsmParser::parseDirectiveSymbolAttribute(MCSymbolAttr Attr) {
    auto parseOp = [&]() -> bool {
      StringRef Name;
      SMLoc Loc = getTok().getLoc();
      if (parseIdentifier(Name))
        return Error(Loc, "expected identifier");
      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");
  
      if (!getStreamer().EmitSymbolAttribute(Sym, Attr))
        return Error(Loc, "unable to emit symbol attribute");
      return false;
    };
  
    if (parseMany(parseOp))
      return addErrorSuffix(" in directive");
    return false;
  }
  
  /// parseDirectiveComm
  ///  ::= ( .comm | .lcomm ) identifier , size_expression [ , align_expression ]
  bool AsmParser::parseDirectiveComm(bool IsLocal) {
    if (checkForValidSection())
      return true;
  
    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 (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.comm' or '.lcomm' directive"))
      return true;
  
    // 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");
  
    Sym->redefineIfPossible();
    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 (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.abort' directive"))
      return true;
  
    if (Str.empty())
      return Error(Loc, ".abort detected. Assembly stopping.");
    else
      return Error(Loc, ".abort '" + Str + "' detected. Assembly stopping.");
    // FIXME: Actually abort assembly here.
  
    return false;
  }
  
  /// parseDirectiveInclude
  ///  ::= .include "filename"
  bool AsmParser::parseDirectiveInclude() {
    // Allow the strings to have escaped octal character sequence.
    std::string Filename;
    SMLoc IncludeLoc = getTok().getLoc();
  
    if (check(getTok().isNot(AsmToken::String),
              "expected string in '.include' directive") ||
        parseEscapedString(Filename) ||
        check(getTok().isNot(AsmToken::EndOfStatement),
              "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.
        check(enterIncludeFile(Filename), IncludeLoc,
              "Could not find include file '" + Filename + "'"))
      return true;
  
    return false;
  }
  
  /// parseDirectiveIncbin
  ///  ::= .incbin "filename" [ , skip [ , count ] ]
  bool AsmParser::parseDirectiveIncbin() {
    // Allow the strings to have escaped octal character sequence.
    std::string Filename;
    SMLoc IncbinLoc = getTok().getLoc();
    if (check(getTok().isNot(AsmToken::String),
              "expected string in '.incbin' directive") ||
        parseEscapedString(Filename))
      return true;
  
    int64_t Skip = 0;
    const MCExpr *Count = nullptr;
    SMLoc SkipLoc, CountLoc;
    if (parseOptionalToken(AsmToken::Comma)) {
      // The skip expression can be omitted while specifying the count, e.g:
      //  .incbin "filename",,4
      if (getTok().isNot(AsmToken::Comma)) {
        if (parseTokenLoc(SkipLoc) || parseAbsoluteExpression(Skip))
          return true;
      }
      if (parseOptionalToken(AsmToken::Comma)) {
        CountLoc = getTok().getLoc();
        if (parseExpression(Count))
          return true;
      }
    }
  
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.incbin' directive"))
      return true;
  
    if (check(Skip < 0, SkipLoc, "skip is negative"))
      return true;
  
    // Attempt to process the included file.
    if (processIncbinFile(Filename, Skip, Count, CountLoc))
      return Error(IncbinLoc, "Could not find incbin file '" + Filename + "'");
    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) ||
          parseToken(AsmToken::EndOfStatement,
                     "unexpected token in '.if' directive"))
        return true;
  
      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 (parseToken(AsmToken::EndOfStatement,
                     "unexpected token in '.ifb' directive"))
        return true;
  
      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 (parseToken(AsmToken::Comma, "unexpected token in '.ifc' directive"))
        return true;
  
      StringRef Str2 = parseStringToEndOfStatement();
  
      if (parseToken(AsmToken::EndOfStatement,
                     "unexpected token in '.ifc' directive"))
        return true;
  
      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)
        return TokError("expected string parameter for '.ifeqs' directive");
      return TokError("expected string parameter for '.ifnes' directive");
    }
  
    StringRef String1 = getTok().getStringContents();
    Lex();
  
    if (Lexer.isNot(AsmToken::Comma)) {
      if (ExpectEqual)
        return TokError(
            "expected comma after first string for '.ifeqs' directive");
      return TokError("expected comma after first string for '.ifnes' directive");
    }
  
    Lex();
  
    if (Lexer.isNot(AsmToken::String)) {
      if (ExpectEqual)
        return TokError("expected string parameter for '.ifeqs' directive");
      return TokError("expected string parameter for '.ifnes' directive");
    }
  
    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 (check(parseIdentifier(Name), "expected identifier after '.ifdef'") ||
          parseToken(AsmToken::EndOfStatement, "unexpected token in '.ifdef'"))
        return true;
  
      MCSymbol *Sym = getContext().lookupSymbol(Name);
  
      if (expect_defined)
        TheCondState.CondMet = (Sym && !Sym->isUndefined(false));
      else
        TheCondState.CondMet = (!Sym || Sym->isUndefined(false));
      TheCondState.Ignore = !TheCondState.CondMet;
    }
  
    return false;
  }
  
  /// parseDirectiveElseIf
  /// ::= .elseif expression
  bool AsmParser::parseDirectiveElseIf(SMLoc DirectiveLoc) {
    if (TheCondState.TheCond != AsmCond::IfCond &&
        TheCondState.TheCond != AsmCond::ElseIfCond)
      return Error(DirectiveLoc, "Encountered a .elseif that doesn't follow an"
                                 " .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 (parseToken(AsmToken::EndOfStatement,
                     "unexpected token in '.elseif' directive"))
        return true;
  
      TheCondState.CondMet = ExprValue;
      TheCondState.Ignore = !TheCondState.CondMet;
    }
  
    return false;
  }
  
  /// parseDirectiveElse
  /// ::= .else
  bool AsmParser::parseDirectiveElse(SMLoc DirectiveLoc) {
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.else' directive"))
      return true;
  
    if (TheCondState.TheCond != AsmCond::IfCond &&
        TheCondState.TheCond != AsmCond::ElseIfCond)
      return Error(DirectiveLoc, "Encountered a .else that doesn't follow "
                                 " an .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 (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.end' directive"))
      return true;
  
    while (Lexer.isNot(AsmToken::Eof))
      Lexer.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))
        return TokError(".error argument must be a string");
  
      Message = getTok().getStringContents();
      Lex();
    }
  
    return Error(L, Message);
  }
  
  /// 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 (!parseOptionalToken(AsmToken::EndOfStatement)) {
      if (Lexer.isNot(AsmToken::String))
        return TokError(".warning argument must be a string");
  
      Message = getTok().getStringContents();
      Lex();
      if (parseToken(AsmToken::EndOfStatement,
                     "expected end of statement in '.warning' directive"))
        return true;
    }
  
    return Warning(L, Message);
  }
  
  /// parseDirectiveEndIf
  /// ::= .endif
  bool AsmParser::parseDirectiveEndIf(SMLoc DirectiveLoc) {
    if (parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '.endif' directive"))
      return true;
  
    if ((TheCondState.TheCond == AsmCond::NoCond) || TheCondStack.empty())
      return Error(DirectiveLoc, "Encountered a .endif that doesn't follow "
                                 "an .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[".cold"] = DK_COLD;
    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_func_id"] = DK_CV_FUNC_ID;
    DirectiveKindMap[".cv_loc"] = DK_CV_LOC;
    DirectiveKindMap[".cv_linetable"] = DK_CV_LINETABLE;
    DirectiveKindMap[".cv_inline_linetable"] = DK_CV_INLINE_LINETABLE;
    DirectiveKindMap[".cv_inline_site_id"] = DK_CV_INLINE_SITE_ID;
    DirectiveKindMap[".cv_def_range"] = DK_CV_DEF_RANGE;
    DirectiveKindMap[".cv_string"] = DK_CV_STRING;
    DirectiveKindMap[".cv_stringtable"] = DK_CV_STRINGTABLE;
    DirectiveKindMap[".cv_filechecksums"] = DK_CV_FILECHECKSUMS;
    DirectiveKindMap[".cv_filechecksumoffset"] = DK_CV_FILECHECKSUM_OFFSET;
    DirectiveKindMap[".cv_fpo_data"] = DK_CV_FPO_DATA;
    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_return_column"] = DK_CFI_RETURN_COLUMN;
    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[".cfi_b_key_frame"] = DK_CFI_B_KEY_FRAME;
    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[".altmacro"] = DK_ALTMACRO;
    DirectiveKindMap[".noaltmacro"] = DK_NOALTMACRO;
    DirectiveKindMap[".reloc"] = DK_RELOC;
    DirectiveKindMap[".dc"] = DK_DC;
    DirectiveKindMap[".dc.a"] = DK_DC_A;
    DirectiveKindMap[".dc.b"] = DK_DC_B;
    DirectiveKindMap[".dc.d"] = DK_DC_D;
    DirectiveKindMap[".dc.l"] = DK_DC_L;
    DirectiveKindMap[".dc.s"] = DK_DC_S;
    DirectiveKindMap[".dc.w"] = DK_DC_W;
    DirectiveKindMap[".dc.x"] = DK_DC_X;
    DirectiveKindMap[".dcb"] = DK_DCB;
    DirectiveKindMap[".dcb.b"] = DK_DCB_B;
    DirectiveKindMap[".dcb.d"] = DK_DCB_D;
    DirectiveKindMap[".dcb.l"] = DK_DCB_L;
    DirectiveKindMap[".dcb.s"] = DK_DCB_S;
    DirectiveKindMap[".dcb.w"] = DK_DCB_W;
    DirectiveKindMap[".dcb.x"] = DK_DCB_X;
    DirectiveKindMap[".ds"] = DK_DS;
    DirectiveKindMap[".ds.b"] = DK_DS_B;
    DirectiveKindMap[".ds.d"] = DK_DS_D;
    DirectiveKindMap[".ds.l"] = DK_DS_L;
    DirectiveKindMap[".ds.p"] = DK_DS_P;
    DirectiveKindMap[".ds.s"] = DK_DS_S;
    DirectiveKindMap[".ds.w"] = DK_DS_W;
    DirectiveKindMap[".ds.x"] = DK_DS_X;
    DirectiveKindMap[".print"] = DK_PRINT;
    DirectiveKindMap[".addrsig"] = DK_ADDRSIG;
    DirectiveKindMap[".addrsig_sym"] = DK_ADDRSIG_SYM;
  }
  
  MCAsmMacro *AsmParser::parseMacroLikeBody(SMLoc DirectiveLoc) {
    AsmToken EndToken, StartToken = getTok();
  
    unsigned NestLevel = 0;
    while (true) {
      // Check whether we have reached the end of the file.
      if (getLexer().is(AsmToken::Eof)) {
        printError(DirectiveLoc, "no matching '.endr' in definition");
        return nullptr;
      }
  
      if (Lexer.is(AsmToken::Identifier) &&
          (getTok().getIdentifier() == ".rep" ||
           getTok().getIdentifier() == ".rept" ||
           getTok().getIdentifier() == ".irp" ||
           getTok().getIdentifier() == ".irpc")) {
        ++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)) {
            printError(getTok().getLoc(),
                       "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, getStreamer().getAssemblerPtr())) {
      return Error(CountLoc, "unexpected token in '" + Dir + "' directive");
    }
  
    if (check(Count < 0, CountLoc, "Count is negative") ||
        parseToken(AsmToken::EndOfStatement,
                   "unexpected token in '" + Dir + "' directive"))
      return true;
  
    // 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;
    MCAsmMacroArguments A;
    if (check(parseIdentifier(Parameter.Name),
              "expected identifier in '.irp' directive") ||
        parseToken(AsmToken::Comma, "expected comma in '.irp' directive") ||
        parseMacroArguments(nullptr, A) ||
        parseToken(AsmToken::EndOfStatement, "expected End of Statement"))
      return true;
  
    // 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;
    MCAsmMacroArguments A;
  
    if (check(parseIdentifier(Parameter.Name),
              "expected identifier in '.irpc' directive") ||
        parseToken(AsmToken::Comma, "expected comma in '.irpc' directive") ||
        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.
    if (parseToken(AsmToken::EndOfStatement, "expected end of statement"))
      return true;
  
    // 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;
  }
  
  bool AsmParser::parseDirectivePrint(SMLoc DirectiveLoc) {
    const AsmToken StrTok = getTok();
    Lex();
    if (StrTok.isNot(AsmToken::String) || StrTok.getString().front() != '"')
      return Error(DirectiveLoc, "expected double quoted string after .print");
    if (parseToken(AsmToken::EndOfStatement, "expected end of statement"))
      return true;
    llvm::outs() << StrTok.getStringContents() << '\n';
    return false;
  }
  
  bool AsmParser::parseDirectiveAddrsig() {
    getStreamer().EmitAddrsig();
    return false;
  }
  
  bool AsmParser::parseDirectiveAddrsigSym() {
    StringRef Name;
    if (check(parseIdentifier(Name),
              "expected identifier in '.addrsig_sym' directive"))
      return true;
    MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
    getStreamer().EmitAddrsigSym(Sym);
    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)) {
      // Parse curly braces marking block start/end
      if (parseCurlyBlockScope(AsmStrRewrites))
        continue;
  
      ParseStatementInfo Info(&AsmStrRewrites);
      bool StatementErr = parseStatement(Info, &SI);
  
      if (StatementErr || Info.ParseError) {
        // Emit pending errors if any exist.
        printPendingErrors();
        return true;
      }
  
      // No pending error should exist here.
      assert(!hasPendingError() && "unexpected error from parseStatement");
  
      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;
  
      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_IntelExpr:
        assert(AR.IntelExp.isValid() && "cannot write invalid intel expression");
        if (AR.IntelExp.NeedBracs)
          OS << "[";
        if (AR.IntelExp.hasBaseReg())
          OS << AR.IntelExp.BaseReg;
        if (AR.IntelExp.hasIndexReg())
          OS << (AR.IntelExp.hasBaseReg() ? " + " : "")
             << AR.IntelExp.IndexReg;
        if (AR.IntelExp.Scale > 1)
            OS << " * $$" << AR.IntelExp.Scale;
        if (AR.IntelExp.Imm || !AR.IntelExp.hasRegs())
          OS << (AR.IntelExp.hasRegs() ? " + $$" : "$$") << AR.IntelExp.Imm;
        if (AR.IntelExp.NeedBracs)
          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_EndOfStatement:
        OS << "\n\t";
        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) {
  
    // FIXME: Use better location, we should use proper tokens.
    SMLoc EqualLoc = Parser.getTok().getLoc();
    if (Parser.parseExpression(Value))
      return Parser.TokError("missing expression");
  
    // Note: we don't count b as used in "a = b". This is to allow
    // a = b
    // b = c
  
    if (Parser.parseToken(AsmToken::EndOfStatement))
      return true;
  
    // 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, EqualLoc);
      return false;
    } else
      Sym = Parser.getContext().getOrCreateSymbol(Name);
  
    Sym->setRedefinable(allow_redef);
  
    return false;
  }
  
  } // end namespace MCParserUtils
  } // end namespace llvm
  
  /// Create an MCAsmParser instance.
  MCAsmParser *llvm::createMCAsmParser(SourceMgr &SM, MCContext &C,
                                       MCStreamer &Out, const MCAsmInfo &MAI,
                                       unsigned CB) {
    return new AsmParser(SM, C, Out, MAI, CB);
  }
  