TokenLexer.h revision e5c8ffe09f8fec836b90f23c2a3b996bfc5b09c4
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 TokenLexer(const TokenLexer&); // DO NOT IMPLEMENT 72 void operator=(const TokenLexer&); // DO NOT IMPLEMENT 73public: 74 /// Create a TokenLexer for the specified macro with the specified actual 75 /// arguments. Note that this ctor takes ownership of the ActualArgs pointer. 76 TokenLexer(Token &Tok, MacroArgs *ActualArgs, Preprocessor &pp) 77 : Macro(0), ActualArgs(0), PP(pp), OwnsTokens(false) { 78 Init(Tok, ActualArgs); 79 } 80 81 /// Init - Initialize this TokenLexer to expand from the specified macro 82 /// with the specified argument information. Note that this ctor takes 83 /// ownership of the ActualArgs pointer. 84 void Init(Token &Tok, MacroArgs *ActualArgs); 85 86 /// Create a TokenLexer for the specified token stream. This does not 87 /// take ownership of the specified token vector. 88 TokenLexer(const Token *TokArray, unsigned NumToks, Preprocessor &pp) 89 : Macro(0), ActualArgs(0), PP(pp), OwnsTokens(false) { 90 Init(TokArray, NumToks); 91 } 92 93 /// Init - Initialize this TokenLexer with the specified token stream. 94 /// This does not take ownership of the specified token vector. 95 void Init(const Token *TokArray, unsigned NumToks); 96 97 ~TokenLexer() { destroy(); } 98 99 /// isNextTokenLParen - If the next token lexed will pop this macro off the 100 /// expansion stack, return 2. If the next unexpanded token is a '(', return 101 /// 1, otherwise return 0. 102 unsigned isNextTokenLParen() const; 103 104 /// Lex - Lex and return a token from this macro stream. 105 void Lex(Token &Tok); 106 107private: 108 void destroy(); 109 110 /// isAtEnd - Return true if the next lex call will pop this macro off the 111 /// include stack. 112 bool isAtEnd() const { 113 return CurToken == NumTokens; 114 } 115 116 /// PasteTokens - Tok is the LHS of a ## operator, and CurToken is the ## 117 /// operator. Read the ## and RHS, and paste the LHS/RHS together. If there 118 /// are is another ## after it, chomp it iteratively. Return the result as 119 /// Tok. If this returns true, the caller should immediately return the 120 /// token. 121 bool PasteTokens(Token &Tok); 122 123 /// Expand the arguments of a function-like macro so that we can quickly 124 /// return preexpanded tokens from Tokens. 125 void ExpandFunctionArguments(); 126 127 /// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes 128 /// together to form a comment that comments out everything in the current 129 /// macro, other active macros, and anything left on the current physical 130 /// source line of the instantiated buffer. Handle this by returning the 131 /// first token on the next line. 132 void HandleMicrosoftCommentPaste(Token &Tok); 133}; 134 135} // end namespace clang 136 137#endif 138