src/llvm/tools/clang/include/clang/Lex/TokenLexer.h

   1 //===--- TokenLexer.h - Lex from a token buffer -----------------*- 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 file defines the TokenLexer interface.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_CLANG_TOKENLEXER_H
  15 #define LLVM_CLANG_TOKENLEXER_H
  16
  17 #include "clang/Basic/SourceLocation.h"
  18
  19 namespace clang {
  20   class MacroInfo;
  21   class Preprocessor;
  22   class Token;
  23   class MacroArgs;
  24
  25 /// TokenLexer - This implements a lexer that returns tokens from a macro body
  26 /// or token stream instead of lexing from a character buffer.  This is used for
  27 /// macro expansion and _Pragma handling, for example.
  28 ///
  29 class TokenLexer {
  30   /// Macro - The macro we are expanding from.  This is null if expanding a
  31   /// token stream.
  32   ///
  33   MacroInfo *Macro;
  34
  35   /// ActualArgs - The actual arguments specified for a function-like macro, or
  36   /// null.  The TokenLexer owns the pointed-to object.
  37   MacroArgs *ActualArgs;
  38
  39   /// PP - The current preprocessor object we are expanding for.
  40   ///
  41   Preprocessor &PP;
  42
  43   /// Tokens - This is the pointer to an array of tokens that the macro is
  44   /// defined to, with arguments expanded for function-like macros.  If this is
  45   /// a token stream, these are the tokens we are returning.  This points into
  46   /// the macro definition we are lexing from, a cache buffer that is owned by
  47   /// the preprocessor, or some other buffer that we may or may not own
  48   /// (depending on OwnsTokens).
  49   /// Note that if it points into Preprocessor's cache buffer, the Preprocessor
  50   /// may update the pointer as needed.
  51   const Token *Tokens;
  52   friend class Preprocessor;
  53
  54   /// NumTokens - This is the length of the Tokens array.
  55   ///
  56   unsigned NumTokens;
  57
  58   /// CurToken - This is the next token that Lex will return.
  59   ///
  60   unsigned CurToken;
  61
  62   /// ExpandLocStart/End - The source location range where this macro was
  63   /// expanded.
  64   SourceLocation ExpandLocStart, ExpandLocEnd;
  65
  66   /// \brief Source location pointing at the source location entry chunk that
  67   /// was reserved for the current macro expansion.
  68   SourceLocation MacroExpansionStart;
  69
  70   /// \brief The offset of the macro expansion in the
  71   /// "source location address space".
  72   unsigned MacroStartSLocOffset;
  73
  74   /// \brief Location of the macro definition.
  75   SourceLocation MacroDefStart;
  76   /// \brief Length of the macro definition.
  77   unsigned MacroDefLength;
  78
  79   /// Lexical information about the expansion point of the macro: the identifier
  80   /// that the macro expanded from had these properties.
  81   bool AtStartOfLine : 1;
  82   bool HasLeadingSpace : 1;
  83
  84   /// OwnsTokens - This is true if this TokenLexer allocated the Tokens
  85   /// array, and thus needs to free it when destroyed.  For simple object-like
  86   /// macros (for example) we just point into the token buffer of the macro
  87   /// definition, we don't make a copy of it.
  88   bool OwnsTokens : 1;
  89
  90   /// DisableMacroExpansion - This is true when tokens lexed from the TokenLexer
  91   /// should not be subject to further macro expansion.
  92   bool DisableMacroExpansion : 1;
  93
  94   TokenLexer(const TokenLexer &) LLVM_DELETED_FUNCTION;
  95   void operator=(const TokenLexer &) LLVM_DELETED_FUNCTION;
  96 public:
  97   /// Create a TokenLexer for the specified macro with the specified actual
  98   /// arguments.  Note that this ctor takes ownership of the ActualArgs pointer.
  99   /// ILEnd specifies the location of the ')' for a function-like macro or the
 100   /// identifier for an object-like macro.
 101   TokenLexer(Token &Tok, SourceLocation ILEnd, MacroInfo *MI,
 102              MacroArgs *ActualArgs, Preprocessor &pp)
 103     : Macro(0), ActualArgs(0), PP(pp), OwnsTokens(false) {
 104     Init(Tok, ILEnd, MI, ActualArgs);
 105   }
 106
 107   /// Init - Initialize this TokenLexer to expand from the specified macro
 108   /// with the specified argument information.  Note that this ctor takes
 109   /// ownership of the ActualArgs pointer.  ILEnd specifies the location of the
 110   /// ')' for a function-like macro or the identifier for an object-like macro.
 111   void Init(Token &Tok, SourceLocation ILEnd, MacroInfo *MI,
 112             MacroArgs *ActualArgs);
 113
 114   /// Create a TokenLexer for the specified token stream.  If 'OwnsTokens' is
 115   /// specified, this takes ownership of the tokens and delete[]'s them when
 116   /// the token lexer is empty.
 117   TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion,
 118              bool ownsTokens, Preprocessor &pp)
 119     : Macro(0), ActualArgs(0), PP(pp), OwnsTokens(false) {
 120     Init(TokArray, NumToks, DisableExpansion, ownsTokens);
 121   }
 122
 123   /// Init - Initialize this TokenLexer with the specified token stream.
 124   /// This does not take ownership of the specified token vector.
 125   ///
 126   /// DisableExpansion is true when macro expansion of tokens lexed from this
 127   /// stream should be disabled.
 128   void Init(const Token *TokArray, unsigned NumToks,
 129             bool DisableMacroExpansion, bool OwnsTokens);
 130
 131   ~TokenLexer() { destroy(); }
 132
 133   /// isNextTokenLParen - If the next token lexed will pop this macro off the
 134   /// expansion stack, return 2.  If the next unexpanded token is a '(', return
 135   /// 1, otherwise return 0.
 136   unsigned isNextTokenLParen() const;
 137
 138   /// Lex - Lex and return a token from this macro stream.
 139   void Lex(Token &Tok);
 140
 141   /// isParsingPreprocessorDirective - Return true if we are in the middle of a
 142   /// preprocessor directive.
 143   bool isParsingPreprocessorDirective() const;
 144
 145 private:
 146   void destroy();
 147
 148   /// isAtEnd - Return true if the next lex call will pop this macro off the
 149   /// include stack.
 150   bool isAtEnd() const {
 151     return CurToken == NumTokens;
 152   }
 153
 154   /// PasteTokens - Tok is the LHS of a ## operator, and CurToken is the ##
 155   /// operator.  Read the ## and RHS, and paste the LHS/RHS together.  If there
 156   /// are is another ## after it, chomp it iteratively.  Return the result as
 157   /// Tok.  If this returns true, the caller should immediately return the
 158   /// token.
 159   bool PasteTokens(Token &Tok);
 160
 161   /// Expand the arguments of a function-like macro so that we can quickly
 162   /// return preexpanded tokens from Tokens.
 163   void ExpandFunctionArguments();
 164
 165   /// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes
 166   /// together to form a comment that comments out everything in the current
 167   /// macro, other active macros, and anything left on the current physical
 168   /// source line of the expanded buffer.  Handle this by returning the
 169   /// first token on the next line.
 170   void HandleMicrosoftCommentPaste(Token &Tok);
 171
 172   /// \brief If \p loc is a FileID and points inside the current macro
 173   /// definition, returns the appropriate source location pointing at the
 174   /// macro expansion source location entry.
 175   SourceLocation getExpansionLocForMacroDefLoc(SourceLocation loc) const;
 176
 177   /// \brief Creates SLocEntries and updates the locations of macro argument
 178   /// tokens to their new expanded locations.
 179   ///
 180   /// \param ArgIdSpellLoc the location of the macro argument id inside the
 181   /// macro definition.
 182   void updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc,
 183                                   Token *begin_tokens, Token *end_tokens);
 184 };
 185
 186 }  // end namespace clang
 187
 188 #endif