TokenLexer.h revision e7fb48466afcbf2c4ccdfa658824282fdc3c512c
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 /// InstantiateLocStart/End - The source location range where this macro was 57 /// instantiated. 58 SourceLocation InstantiateLocStart, InstantiateLocEnd; 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 /// ILEnd specifies the location of the ')' for a function-like macro or the 81 /// identifier for an object-like macro. 82 TokenLexer(Token &Tok, SourceLocation ILEnd, MacroArgs *ActualArgs, 83 Preprocessor &pp) 84 : Macro(0), ActualArgs(0), PP(pp), OwnsTokens(false) { 85 Init(Tok, ILEnd, ActualArgs); 86 } 87 88 /// Init - Initialize this TokenLexer to expand from the specified macro 89 /// with the specified argument information. Note that this ctor takes 90 /// ownership of the ActualArgs pointer. ILEnd specifies the location of the 91 /// ')' for a function-like macro or the identifier for an object-like macro. 92 void Init(Token &Tok, SourceLocation ILEnd, MacroArgs *ActualArgs); 93 94 /// Create a TokenLexer for the specified token stream. If 'OwnsTokens' is 95 /// specified, this takes ownership of the tokens and delete[]'s them when 96 /// the token lexer is empty. 97 TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion, 98 bool ownsTokens, Preprocessor &pp) 99 : Macro(0), ActualArgs(0), PP(pp), OwnsTokens(false) { 100 Init(TokArray, NumToks, DisableExpansion, ownsTokens); 101 } 102 103 /// Init - Initialize this TokenLexer with the specified token stream. 104 /// This does not take ownership of the specified token vector. 105 /// 106 /// DisableExpansion is true when macro expansion of tokens lexed from this 107 /// stream should be disabled. 108 void Init(const Token *TokArray, unsigned NumToks, 109 bool DisableMacroExpansion, bool OwnsTokens); 110 111 ~TokenLexer() { destroy(); } 112 113 /// isNextTokenLParen - If the next token lexed will pop this macro off the 114 /// expansion stack, return 2. If the next unexpanded token is a '(', return 115 /// 1, otherwise return 0. 116 unsigned isNextTokenLParen() const; 117 118 /// Lex - Lex and return a token from this macro stream. 119 void Lex(Token &Tok); 120 121private: 122 void destroy(); 123 124 /// isAtEnd - Return true if the next lex call will pop this macro off the 125 /// include stack. 126 bool isAtEnd() const { 127 return CurToken == NumTokens; 128 } 129 130 /// PasteTokens - Tok is the LHS of a ## operator, and CurToken is the ## 131 /// operator. Read the ## and RHS, and paste the LHS/RHS together. If there 132 /// are is another ## after it, chomp it iteratively. Return the result as 133 /// Tok. If this returns true, the caller should immediately return the 134 /// token. 135 bool PasteTokens(Token &Tok); 136 137 /// Expand the arguments of a function-like macro so that we can quickly 138 /// return preexpanded tokens from Tokens. 139 void ExpandFunctionArguments(); 140 141 /// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes 142 /// together to form a comment that comments out everything in the current 143 /// macro, other active macros, and anything left on the current physical 144 /// source line of the instantiated buffer. Handle this by returning the 145 /// first token on the next line. 146 void HandleMicrosoftCommentPaste(Token &Tok); 147}; 148 149} // end namespace clang 150 151#endif 152