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_LEX_TOKENLEXER_H 15 #define LLVM_CLANG_LEX_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 // NextTokGetsSpace - When this is true, the next token appended to the 85 // output list during function argument expansion will get a leading space, 86 // regardless of whether it had one to begin with or not. This is used for 87 // placemarker support. If still true after function argument expansion, the 88 // leading space will be applied to the first token following the macro 89 // expansion. 90 bool NextTokGetsSpace : 1; 91 92 /// OwnsTokens - This is true if this TokenLexer allocated the Tokens 93 /// array, and thus needs to free it when destroyed. For simple object-like 94 /// macros (for example) we just point into the token buffer of the macro 95 /// definition, we don't make a copy of it. 96 bool OwnsTokens : 1; 97 98 /// DisableMacroExpansion - This is true when tokens lexed from the TokenLexer 99 /// should not be subject to further macro expansion. 100 bool DisableMacroExpansion : 1; 101 102 TokenLexer(const TokenLexer &) = delete; 103 void operator=(const TokenLexer &) = delete; 104 public: 105 /// Create a TokenLexer for the specified macro with the specified actual 106 /// arguments. Note that this ctor takes ownership of the ActualArgs pointer. 107 /// ILEnd specifies the location of the ')' for a function-like macro or the 108 /// identifier for an object-like macro. TokenLexer(Token & Tok,SourceLocation ILEnd,MacroInfo * MI,MacroArgs * ActualArgs,Preprocessor & pp)109 TokenLexer(Token &Tok, SourceLocation ILEnd, MacroInfo *MI, 110 MacroArgs *ActualArgs, Preprocessor &pp) 111 : Macro(nullptr), ActualArgs(nullptr), PP(pp), OwnsTokens(false) { 112 Init(Tok, ILEnd, MI, ActualArgs); 113 } 114 115 /// Init - Initialize this TokenLexer to expand from the specified macro 116 /// with the specified argument information. Note that this ctor takes 117 /// ownership of the ActualArgs pointer. ILEnd specifies the location of the 118 /// ')' for a function-like macro or the identifier for an object-like macro. 119 void Init(Token &Tok, SourceLocation ILEnd, MacroInfo *MI, 120 MacroArgs *ActualArgs); 121 122 /// Create a TokenLexer for the specified token stream. If 'OwnsTokens' is 123 /// specified, this takes ownership of the tokens and delete[]'s them when 124 /// the token lexer is empty. TokenLexer(const Token * TokArray,unsigned NumToks,bool DisableExpansion,bool ownsTokens,Preprocessor & pp)125 TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion, 126 bool ownsTokens, Preprocessor &pp) 127 : Macro(nullptr), ActualArgs(nullptr), PP(pp), OwnsTokens(false) { 128 Init(TokArray, NumToks, DisableExpansion, ownsTokens); 129 } 130 131 /// Init - Initialize this TokenLexer with the specified token stream. 132 /// This does not take ownership of the specified token vector. 133 /// 134 /// DisableExpansion is true when macro expansion of tokens lexed from this 135 /// stream should be disabled. 136 void Init(const Token *TokArray, unsigned NumToks, 137 bool DisableMacroExpansion, bool OwnsTokens); 138 ~TokenLexer()139 ~TokenLexer() { destroy(); } 140 141 /// isNextTokenLParen - If the next token lexed will pop this macro off the 142 /// expansion stack, return 2. If the next unexpanded token is a '(', return 143 /// 1, otherwise return 0. 144 unsigned isNextTokenLParen() const; 145 146 /// Lex - Lex and return a token from this macro stream. 147 bool Lex(Token &Tok); 148 149 /// isParsingPreprocessorDirective - Return true if we are in the middle of a 150 /// preprocessor directive. 151 bool isParsingPreprocessorDirective() const; 152 153 private: 154 void destroy(); 155 156 /// isAtEnd - Return true if the next lex call will pop this macro off the 157 /// include stack. isAtEnd()158 bool isAtEnd() const { 159 return CurToken == NumTokens; 160 } 161 162 /// PasteTokens - Tok is the LHS of a ## operator, and CurToken is the ## 163 /// operator. Read the ## and RHS, and paste the LHS/RHS together. If there 164 /// are is another ## after it, chomp it iteratively. Return the result as 165 /// Tok. If this returns true, the caller should immediately return the 166 /// token. 167 bool PasteTokens(Token &Tok); 168 169 /// Expand the arguments of a function-like macro so that we can quickly 170 /// return preexpanded tokens from Tokens. 171 void ExpandFunctionArguments(); 172 173 /// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes 174 /// together to form a comment that comments out everything in the current 175 /// macro, other active macros, and anything left on the current physical 176 /// source line of the expanded buffer. Handle this by returning the 177 /// first token on the next line. 178 void HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc); 179 180 /// \brief If \p loc is a FileID and points inside the current macro 181 /// definition, returns the appropriate source location pointing at the 182 /// macro expansion source location entry. 183 SourceLocation getExpansionLocForMacroDefLoc(SourceLocation loc) const; 184 185 /// \brief Creates SLocEntries and updates the locations of macro argument 186 /// tokens to their new expanded locations. 187 /// 188 /// \param ArgIdSpellLoc the location of the macro argument id inside the 189 /// macro definition. 190 void updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc, 191 Token *begin_tokens, Token *end_tokens); 192 193 /// Remove comma ahead of __VA_ARGS__, if present, according to compiler 194 /// dialect settings. Returns true if the comma is removed. 195 bool MaybeRemoveCommaBeforeVaArgs(SmallVectorImpl<Token> &ResultToks, 196 bool HasPasteOperator, 197 MacroInfo *Macro, unsigned MacroArgNo, 198 Preprocessor &PP); 199 200 void PropagateLineStartLeadingSpaceInfo(Token &Result); 201 }; 202 203 } // end namespace clang 204 205 #endif 206