TokenLexer.h revision 6b884508c3bc97cc9df9516adb92fbf88dd0a2e4
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 19namespace clang { 20 class MacroInfo; 21 class Preprocessor; 22 class Token; 23 class MacroArgs; 24 25/// TokenLexer - This implements a lexer that returns token 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/// 29class 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. 46 const Token *Tokens; 47 48 /// NumTokens - This is the length of the Tokens array. 49 /// 50 unsigned NumTokens; 51 52 /// CurToken - This is the next token that Lex will return. 53 /// 54 unsigned CurToken; 55 56 /// InstantiateLoc - The source location where this macro was instantiated. 57 /// 58 SourceLocation InstantiateLoc; 59 60 /// Lexical information about the expansion point of the macro: the identifier 61 /// that the macro expanded from had these properties. 62 bool AtStartOfLine : 1; 63 bool HasLeadingSpace : 1; 64 65 /// OwnsTokens - This is true if this TokenLexer allocated the Tokens 66 /// array, and thus needs to free it when destroyed. For simple object-like 67 /// macros (for example) we just point into the token buffer of the macro 68 /// definition, we don't make a copy of it. 69 bool OwnsTokens : 1; 70 71 /// DisableMacroExpansion - This is true when tokens lexed from the TokenLexer 72 /// should not be subject to further macro expansion. 73 bool DisableMacroExpansion : 1; 74 75 TokenLexer(const TokenLexer&); // DO NOT IMPLEMENT 76 void operator=(const TokenLexer&); // DO NOT IMPLEMENT 77public: 78 /// Create a TokenLexer for the specified macro with the specified actual 79 /// arguments. Note that this ctor takes ownership of the ActualArgs pointer. 80 TokenLexer(Token &Tok, MacroArgs *ActualArgs, Preprocessor &pp) 81 : Macro(0), ActualArgs(0), PP(pp), OwnsTokens(false) { 82 Init(Tok, ActualArgs); 83 } 84 85 /// Init - Initialize this TokenLexer to expand from the specified macro 86 /// with the specified argument information. Note that this ctor takes 87 /// ownership of the ActualArgs pointer. 88 void Init(Token &Tok, MacroArgs *ActualArgs); 89 90 /// Create a TokenLexer for the specified token stream. This does not 91 /// take ownership of the specified token vector. 92 TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion, 93 bool OwnsTokens, Preprocessor &pp) 94 : Macro(0), ActualArgs(0), PP(pp), OwnsTokens(false) { 95 Init(TokArray, NumToks, DisableExpansion, OwnsTokens); 96 } 97 98 /// Init - Initialize this TokenLexer with the specified token stream. 99 /// This does not take ownership of the specified token vector. 100 /// 101 /// DisableExpansion is true when macro expansion of tokens lexed from this 102 /// stream should be disabled. 103 void Init(const Token *TokArray, unsigned NumToks, 104 bool DisableMacroExpansion, bool OwnsTokens); 105 106 ~TokenLexer() { destroy(); } 107 108 /// isNextTokenLParen - If the next token lexed will pop this macro off the 109 /// expansion stack, return 2. If the next unexpanded token is a '(', return 110 /// 1, otherwise return 0. 111 unsigned isNextTokenLParen() const; 112 113 /// Lex - Lex and return a token from this macro stream. 114 void Lex(Token &Tok); 115 116private: 117 void destroy(); 118 119 /// isAtEnd - Return true if the next lex call will pop this macro off the 120 /// include stack. 121 bool isAtEnd() const { 122 return CurToken == NumTokens; 123 } 124 125 /// PasteTokens - Tok is the LHS of a ## operator, and CurToken is the ## 126 /// operator. Read the ## and RHS, and paste the LHS/RHS together. If there 127 /// are is another ## after it, chomp it iteratively. Return the result as 128 /// Tok. If this returns true, the caller should immediately return the 129 /// token. 130 bool PasteTokens(Token &Tok); 131 132 /// Expand the arguments of a function-like macro so that we can quickly 133 /// return preexpanded tokens from Tokens. 134 void ExpandFunctionArguments(); 135 136 /// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes 137 /// together to form a comment that comments out everything in the current 138 /// macro, other active macros, and anything left on the current physical 139 /// source line of the instantiated buffer. Handle this by returning the 140 /// first token on the next line. 141 void HandleMicrosoftCommentPaste(Token &Tok); 142}; 143 144} // end namespace clang 145 146#endif 147