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 #include "llvm/ADT/ArrayRef.h" 19 20 namespace clang { 21 class MacroInfo; 22 class Preprocessor; 23 class Token; 24 class MacroArgs; 25 class VAOptExpansionContext; 26 27 /// TokenLexer - This implements a lexer that returns tokens from a macro body 28 /// or token stream instead of lexing from a character buffer. This is used for 29 /// macro expansion and _Pragma handling, for example. 30 /// 31 class TokenLexer { 32 /// Macro - The macro we are expanding from. This is null if expanding a 33 /// token stream. 34 /// 35 MacroInfo *Macro; 36 37 /// ActualArgs - The actual arguments specified for a function-like macro, or 38 /// null. The TokenLexer owns the pointed-to object. 39 MacroArgs *ActualArgs; 40 41 /// PP - The current preprocessor object we are expanding for. 42 /// 43 Preprocessor &PP; 44 45 /// Tokens - This is the pointer to an array of tokens that the macro is 46 /// defined to, with arguments expanded for function-like macros. If this is 47 /// a token stream, these are the tokens we are returning. This points into 48 /// the macro definition we are lexing from, a cache buffer that is owned by 49 /// the preprocessor, or some other buffer that we may or may not own 50 /// (depending on OwnsTokens). 51 /// Note that if it points into Preprocessor's cache buffer, the Preprocessor 52 /// may update the pointer as needed. 53 const Token *Tokens; 54 friend class Preprocessor; 55 56 /// NumTokens - This is the length of the Tokens array. 57 /// 58 unsigned NumTokens; 59 60 /// This is the index of the next token that Lex will return. 61 /// 62 unsigned CurTokenIdx; 63 64 /// ExpandLocStart/End - The source location range where this macro was 65 /// expanded. 66 SourceLocation ExpandLocStart, ExpandLocEnd; 67 68 /// \brief Source location pointing at the source location entry chunk that 69 /// was reserved for the current macro expansion. 70 SourceLocation MacroExpansionStart; 71 72 /// \brief The offset of the macro expansion in the 73 /// "source location address space". 74 unsigned MacroStartSLocOffset; 75 76 /// \brief Location of the macro definition. 77 SourceLocation MacroDefStart; 78 /// \brief Length of the macro definition. 79 unsigned MacroDefLength; 80 81 /// Lexical information about the expansion point of the macro: the identifier 82 /// that the macro expanded from had these properties. 83 bool AtStartOfLine : 1; 84 bool HasLeadingSpace : 1; 85 86 // NextTokGetsSpace - When this is true, the next token appended to the 87 // output list during function argument expansion will get a leading space, 88 // regardless of whether it had one to begin with or not. This is used for 89 // placemarker support. If still true after function argument expansion, the 90 // leading space will be applied to the first token following the macro 91 // expansion. 92 bool NextTokGetsSpace : 1; 93 94 /// OwnsTokens - This is true if this TokenLexer allocated the Tokens 95 /// array, and thus needs to free it when destroyed. For simple object-like 96 /// macros (for example) we just point into the token buffer of the macro 97 /// definition, we don't make a copy of it. 98 bool OwnsTokens : 1; 99 100 /// DisableMacroExpansion - This is true when tokens lexed from the TokenLexer 101 /// should not be subject to further macro expansion. 102 bool DisableMacroExpansion : 1; 103 104 TokenLexer(const TokenLexer &) = delete; 105 void operator=(const TokenLexer &) = delete; 106 public: 107 /// Create a TokenLexer for the specified macro with the specified actual 108 /// arguments. Note that this ctor takes ownership of the ActualArgs pointer. 109 /// ILEnd specifies the location of the ')' for a function-like macro or the 110 /// identifier for an object-like macro. 111 TokenLexer(Token &Tok, SourceLocation ILEnd, MacroInfo *MI, 112 MacroArgs *ActualArgs, Preprocessor &pp) 113 : Macro(nullptr), ActualArgs(nullptr), PP(pp), OwnsTokens(false) { 114 Init(Tok, ILEnd, MI, ActualArgs); 115 } 116 117 /// Init - Initialize this TokenLexer to expand from the specified macro 118 /// with the specified argument information. Note that this ctor takes 119 /// ownership of the ActualArgs pointer. ILEnd specifies the location of the 120 /// ')' for a function-like macro or the identifier for an object-like macro. 121 void Init(Token &Tok, SourceLocation ILEnd, MacroInfo *MI, 122 MacroArgs *ActualArgs); 123 124 /// Create a TokenLexer for the specified token stream. If 'OwnsTokens' is 125 /// specified, this takes ownership of the tokens and delete[]'s them when 126 /// the token lexer is empty. 127 TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion, 128 bool ownsTokens, Preprocessor &pp) 129 : Macro(nullptr), ActualArgs(nullptr), PP(pp), OwnsTokens(false) { 130 Init(TokArray, NumToks, DisableExpansion, ownsTokens); 131 } 132 133 /// Init - Initialize this TokenLexer with the specified token stream. 134 /// This does not take ownership of the specified token vector. 135 /// 136 /// DisableExpansion is true when macro expansion of tokens lexed from this 137 /// stream should be disabled. 138 void Init(const Token *TokArray, unsigned NumToks, 139 bool DisableMacroExpansion, bool OwnsTokens); 140 141 ~TokenLexer() { destroy(); } 142 143 /// isNextTokenLParen - If the next token lexed will pop this macro off the 144 /// expansion stack, return 2. If the next unexpanded token is a '(', return 145 /// 1, otherwise return 0. 146 unsigned isNextTokenLParen() const; 147 148 /// Lex - Lex and return a token from this macro stream. 149 bool Lex(Token &Tok); 150 151 /// isParsingPreprocessorDirective - Return true if we are in the middle of a 152 /// preprocessor directive. 153 bool isParsingPreprocessorDirective() const; 154 155 private: 156 void destroy(); 157 158 /// isAtEnd - Return true if the next lex call will pop this macro off the 159 /// include stack. 160 bool isAtEnd() const { 161 return CurTokenIdx == NumTokens; 162 } 163 164 /// Concatenates the next (sub-)sequence of \p Tokens separated by '##' 165 /// starting with LHSTok - stopping when we encounter a token that is neither 166 /// '##' nor preceded by '##'. Places the result back into \p LHSTok and sets 167 /// \p CurIdx to point to the token following the last one that was pasted. 168 /// 169 /// Also performs the MSVC extension wide-literal token pasting involved with: 170 /// \code L #macro-arg. \endcode 171 /// 172 /// \param[in,out] LHSTok - Contains the token to the left of '##' in \p 173 /// Tokens upon entry and will contain the resulting concatenated Token upon 174 /// exit. 175 /// 176 /// \param[in] TokenStream - The stream of Tokens we are lexing from. 177 /// 178 /// \param[in,out] CurIdx - Upon entry, \pTokens[\pCurIdx] must equal '##' 179 /// (with the exception of the MSVC extension mentioned above). Upon exit, it 180 /// is set to the index of the token following the last token that was 181 /// concatenated together. 182 /// 183 /// \returns If this returns true, the caller should immediately return the 184 /// token. 185 186 bool pasteTokens(Token &LHSTok, ArrayRef<Token> TokenStream, 187 unsigned int &CurIdx); 188 189 /// Calls pasteTokens above, passing in the '*this' object's Tokens and 190 /// CurTokenIdx data members. 191 bool pasteTokens(Token &Tok); 192 193 194 /// Takes the tail sequence of tokens within ReplacementToks that represent 195 /// the just expanded __VA_OPT__ tokens (possibly zero tokens) and transforms 196 /// them into a string. \p VCtx is used to determine which token represents 197 /// the first __VA_OPT__ replacement token. 198 /// 199 /// \param[in,out] ReplacementToks - Contains the current Replacement Tokens 200 /// (prior to rescanning and token pasting), the tail end of which represents 201 /// the tokens just expanded through __VA_OPT__ processing. These (sub) 202 /// sequence of tokens are folded into one stringified token. 203 /// 204 /// \param[in] VCtx - contains relevent contextual information about the 205 /// state of the tokens around and including the __VA_OPT__ token, necessary 206 /// for stringification. 207 208 void stringifyVAOPTContents(SmallVectorImpl<Token> &ReplacementToks, 209 const VAOptExpansionContext &VCtx, 210 SourceLocation VAOPTClosingParenLoc); 211 212 /// Expand the arguments of a function-like macro so that we can quickly 213 /// return preexpanded tokens from Tokens. 214 void ExpandFunctionArguments(); 215 216 /// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes 217 /// together to form a comment that comments out everything in the current 218 /// macro, other active macros, and anything left on the current physical 219 /// source line of the expanded buffer. Handle this by returning the 220 /// first token on the next line. 221 void HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc); 222 223 /// \brief If \p loc is a FileID and points inside the current macro 224 /// definition, returns the appropriate source location pointing at the 225 /// macro expansion source location entry. 226 SourceLocation getExpansionLocForMacroDefLoc(SourceLocation loc) const; 227 228 /// \brief Creates SLocEntries and updates the locations of macro argument 229 /// tokens to their new expanded locations. 230 /// 231 /// \param ArgIdSpellLoc the location of the macro argument id inside the 232 /// macro definition. 233 void updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc, 234 Token *begin_tokens, Token *end_tokens); 235 236 /// Remove comma ahead of __VA_ARGS__, if present, according to compiler 237 /// dialect settings. Returns true if the comma is removed. 238 bool MaybeRemoveCommaBeforeVaArgs(SmallVectorImpl<Token> &ResultToks, 239 bool HasPasteOperator, 240 MacroInfo *Macro, unsigned MacroArgNo, 241 Preprocessor &PP); 242 243 void PropagateLineStartLeadingSpaceInfo(Token &Result); 244 }; 245 246 } // end namespace clang 247 248 #endif 249
