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      1 //===- TGLexer.h - Lexer for TableGen Files ---------------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This class represents the Lexer for tablegen files.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef TGLEXER_H
     15 #define TGLEXER_H
     16 
     17 #include "llvm/Support/DataTypes.h"
     18 #include <string>
     19 #include <vector>
     20 #include <cassert>
     21 
     22 namespace llvm {
     23 class MemoryBuffer;
     24 class SourceMgr;
     25 class SMLoc;
     26 class Twine;
     27 
     28 namespace tgtok {
     29   enum TokKind {
     30     // Markers
     31     Eof, Error,
     32 
     33     // Tokens with no info.
     34     minus, plus,        // - +
     35     l_square, r_square, // [ ]
     36     l_brace, r_brace,   // { }
     37     l_paren, r_paren,   // ( )
     38     less, greater,      // < >
     39     colon, semi,        // : ;
     40     comma, period,      // , .
     41     equal, question,    // = ?
     42     paste,              // #
     43 
     44     // Keywords.
     45     Bit, Bits, Class, Code, Dag, Def, Foreach, Defm, Field, In, Int, Let, List,
     46     MultiClass, String,
     47 
     48     // !keywords.
     49     XConcat, XSRA, XSRL, XSHL, XStrConcat, XCast, XSubst,
     50     XForEach, XHead, XTail, XEmpty, XIf, XEq,
     51 
     52     // Integer value.
     53     IntVal,
     54 
     55     // String valued tokens.
     56     Id, StrVal, VarName, CodeFragment
     57   };
     58 }
     59 
     60 /// TGLexer - TableGen Lexer class.
     61 class TGLexer {
     62   SourceMgr &SrcMgr;
     63 
     64   const char *CurPtr;
     65   const MemoryBuffer *CurBuf;
     66 
     67   // Information about the current token.
     68   const char *TokStart;
     69   tgtok::TokKind CurCode;
     70   std::string CurStrVal;  // This is valid for ID, STRVAL, VARNAME, CODEFRAGMENT
     71   int64_t CurIntVal;      // This is valid for INTVAL.
     72 
     73   /// CurBuffer - This is the current buffer index we're lexing from as managed
     74   /// by the SourceMgr object.
     75   int CurBuffer;
     76   /// Dependencies - This is the list of all included files.
     77   std::vector<std::string> Dependencies;
     78 
     79 public:
     80   TGLexer(SourceMgr &SrcMgr);
     81   ~TGLexer() {}
     82 
     83   tgtok::TokKind Lex() {
     84     return CurCode = LexToken();
     85   }
     86 
     87   const std::vector<std::string> &getDependencies() const {
     88     return Dependencies;
     89   }
     90 
     91   tgtok::TokKind getCode() const { return CurCode; }
     92 
     93   const std::string &getCurStrVal() const {
     94     assert((CurCode == tgtok::Id || CurCode == tgtok::StrVal ||
     95             CurCode == tgtok::VarName || CurCode == tgtok::CodeFragment) &&
     96            "This token doesn't have a string value");
     97     return CurStrVal;
     98   }
     99   int64_t getCurIntVal() const {
    100     assert(CurCode == tgtok::IntVal && "This token isn't an integer");
    101     return CurIntVal;
    102   }
    103 
    104   SMLoc getLoc() const;
    105 
    106 private:
    107   /// LexToken - Read the next token and return its code.
    108   tgtok::TokKind LexToken();
    109 
    110   tgtok::TokKind ReturnError(const char *Loc, const Twine &Msg);
    111 
    112   int getNextChar();
    113   int peekNextChar(int Index);
    114   void SkipBCPLComment();
    115   bool SkipCComment();
    116   tgtok::TokKind LexIdentifier();
    117   bool LexInclude();
    118   tgtok::TokKind LexString();
    119   tgtok::TokKind LexVarName();
    120   tgtok::TokKind LexNumber();
    121   tgtok::TokKind LexBracket();
    122   tgtok::TokKind LexExclaim();
    123 };
    124 
    125 } // end namespace llvm
    126 
    127 #endif
    128