1 //===- TokenLexer.h - Lex from a token buffer -------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file defines the TokenLexer interface. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_CLANG_LEX_TOKENLEXER_H 14 #define LLVM_CLANG_LEX_TOKENLEXER_H 15 16 #include "clang/Basic/SourceLocation.h" 17 #include "llvm/ADT/ArrayRef.h" 18 19 namespace clang { 20 21 class MacroArgs; 22 class MacroInfo; 23 class Preprocessor; 24 class Token; 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 class TokenLexer { 31 friend class Preprocessor; 32 33 /// The macro we are expanding from. This is null if expanding a token stream. 34 MacroInfo *Macro = nullptr; 35 36 /// The actual arguments specified for a function-like macro, or null. The 37 /// TokenLexer owns the pointed-to object. 38 MacroArgs *ActualArgs = nullptr; 39 40 /// The current preprocessor object we are expanding for. 41 Preprocessor &PP; 42 43 /// 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 53 /// This is the length of the Tokens array. 54 unsigned NumTokens; 55 56 /// This is the index of the next token that Lex will return. 57 unsigned CurTokenIdx; 58 59 /// The source location range where this macro was expanded. 60 SourceLocation ExpandLocStart, ExpandLocEnd; 61 62 /// Source location pointing at the source location entry chunk that 63 /// was reserved for the current macro expansion. 64 SourceLocation MacroExpansionStart; 65 66 /// The offset of the macro expansion in the 67 /// "source location address space". 68 unsigned MacroStartSLocOffset; 69 70 /// Location of the macro definition. 71 SourceLocation MacroDefStart; 72 73 /// Length of the macro definition. 74 unsigned MacroDefLength; 75 76 /// Lexical information about the expansion point of the macro: the identifier 77 /// that the macro expanded from had these properties. 78 bool AtStartOfLine : 1; 79 bool HasLeadingSpace : 1; 80 81 // When this is true, the next token appended to the 82 // output list during function argument expansion will get a leading space, 83 // regardless of whether it had one to begin with or not. This is used for 84 // placemarker support. If still true after function argument expansion, the 85 // leading space will be applied to the first token following the macro 86 // expansion. 87 bool NextTokGetsSpace : 1; 88 89 /// This is true if this TokenLexer allocated the Tokens 90 /// array, and thus needs to free it when destroyed. For simple object-like 91 /// macros (for example) we just point into the token buffer of the macro 92 /// definition, we don't make a copy of it. 93 bool OwnsTokens : 1; 94 95 /// This is true when tokens lexed from the TokenLexer 96 /// should not be subject to further macro expansion. 97 bool DisableMacroExpansion : 1; 98 99 /// When true, the produced tokens have Token::IsReinjected flag set. 100 /// See the flag documentation for details. 101 bool IsReinject : 1; 102 103 public: 104 /// Create a TokenLexer for the specified macro with the specified actual 105 /// arguments. Note that this ctor takes ownership of the ActualArgs pointer. 106 /// ILEnd specifies the location of the ')' for a function-like macro or the 107 /// identifier for an object-like macro. TokenLexer(Token & Tok,SourceLocation ILEnd,MacroInfo * MI,MacroArgs * ActualArgs,Preprocessor & pp)108 TokenLexer(Token &Tok, SourceLocation ILEnd, MacroInfo *MI, 109 MacroArgs *ActualArgs, Preprocessor &pp) 110 : PP(pp), OwnsTokens(false) { 111 Init(Tok, ILEnd, MI, ActualArgs); 112 } 113 114 /// Create a TokenLexer for the specified token stream. If 'OwnsTokens' is 115 /// specified, this takes ownership of the tokens and delete[]'s them when 116 /// the token lexer is empty. TokenLexer(const Token * TokArray,unsigned NumToks,bool DisableExpansion,bool ownsTokens,bool isReinject,Preprocessor & pp)117 TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion, 118 bool ownsTokens, bool isReinject, Preprocessor &pp) 119 : PP(pp), OwnsTokens(false) { 120 Init(TokArray, NumToks, DisableExpansion, ownsTokens, isReinject); 121 } 122 123 TokenLexer(const TokenLexer &) = delete; 124 TokenLexer &operator=(const TokenLexer &) = delete; ~TokenLexer()125 ~TokenLexer() { destroy(); } 126 127 /// Initialize this TokenLexer to expand from the specified macro 128 /// with the specified argument information. Note that this ctor takes 129 /// ownership of the ActualArgs pointer. ILEnd specifies the location of the 130 /// ')' for a function-like macro or the identifier for an object-like macro. 131 void Init(Token &Tok, SourceLocation ELEnd, MacroInfo *MI, 132 MacroArgs *Actuals); 133 134 /// Initialize this TokenLexer with the specified token stream. 135 /// This does not take ownership of the specified token vector. 136 /// 137 /// DisableExpansion is true when macro expansion of tokens lexed from this 138 /// stream should be disabled. 139 void Init(const Token *TokArray, unsigned NumToks, bool DisableMacroExpansion, 140 bool OwnsTokens, bool IsReinject); 141 142 /// If the next token lexed will pop this macro off the 143 /// expansion stack, return 2. If the next unexpanded token is a '(', return 144 /// 1, otherwise return 0. 145 unsigned isNextTokenLParen() const; 146 147 /// Lex and return a token from this macro stream. 148 bool Lex(Token &Tok); 149 150 /// isParsingPreprocessorDirective - Return true if we are in the middle of a 151 /// preprocessor directive. 152 bool isParsingPreprocessorDirective() const; 153 154 private: 155 void destroy(); 156 157 /// Return true if the next lex call will pop this macro off the include 158 /// stack. isAtEnd()159 bool isAtEnd() const { 160 return CurTokenIdx == NumTokens; 161 } 162 163 /// Concatenates the next (sub-)sequence of \p Tokens separated by '##' 164 /// starting with LHSTok - stopping when we encounter a token that is neither 165 /// '##' nor preceded by '##'. Places the result back into \p LHSTok and sets 166 /// \p CurIdx to point to the token following the last one that was pasted. 167 /// 168 /// Also performs the MSVC extension wide-literal token pasting involved with: 169 /// \code L #macro-arg. \endcode 170 /// 171 /// \param[in,out] LHSTok - Contains the token to the left of '##' in \p 172 /// Tokens upon entry and will contain the resulting concatenated Token upon 173 /// exit. 174 /// 175 /// \param[in] TokenStream - The stream of Tokens we are lexing from. 176 /// 177 /// \param[in,out] CurIdx - Upon entry, \pTokens[\pCurIdx] must equal '##' 178 /// (with the exception of the MSVC extension mentioned above). Upon exit, it 179 /// is set to the index of the token following the last token that was 180 /// concatenated together. 181 /// 182 /// \returns If this returns true, the caller should immediately return the 183 /// token. 184 bool pasteTokens(Token &LHSTok, ArrayRef<Token> TokenStream, 185 unsigned int &CurIdx); 186 187 /// Calls pasteTokens above, passing in the '*this' object's Tokens and 188 /// CurTokenIdx data members. 189 bool pasteTokens(Token &Tok); 190 191 192 /// Takes the tail sequence of tokens within ReplacementToks that represent 193 /// the just expanded __VA_OPT__ tokens (possibly zero tokens) and transforms 194 /// them into a string. \p VCtx is used to determine which token represents 195 /// the first __VA_OPT__ replacement token. 196 /// 197 /// \param[in,out] ResultToks - Contains the current Replacement Tokens 198 /// (prior to rescanning and token pasting), the tail end of which represents 199 /// the tokens just expanded through __VA_OPT__ processing. These (sub) 200 /// sequence of tokens are folded into one stringified token. 201 /// 202 /// \param[in] VCtx - contains relevant contextual information about the 203 /// state of the tokens around and including the __VA_OPT__ token, necessary 204 /// for stringification. 205 void stringifyVAOPTContents(SmallVectorImpl<Token> &ResultToks, 206 const VAOptExpansionContext &VCtx, 207 SourceLocation VAOPTClosingParenLoc); 208 209 /// Expand the arguments of a function-like macro so that we can quickly 210 /// return preexpanded tokens from Tokens. 211 void ExpandFunctionArguments(); 212 213 /// In microsoft compatibility mode, /##/ pastes 214 /// together to form a comment that comments out everything in the current 215 /// macro, other active macros, and anything left on the current physical 216 /// source line of the expanded buffer. Handle this by returning the 217 /// first token on the next line. 218 void HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc); 219 220 /// If \p loc is a FileID and points inside the current macro 221 /// definition, returns the appropriate source location pointing at the 222 /// macro expansion source location entry. 223 SourceLocation getExpansionLocForMacroDefLoc(SourceLocation loc) const; 224 225 /// Creates SLocEntries and updates the locations of macro argument 226 /// tokens to their new expanded locations. 227 /// 228 /// \param ArgIdSpellLoc the location of the macro argument id inside the 229 /// macro definition. 230 void updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc, 231 Token *begin_tokens, Token *end_tokens); 232 233 /// Remove comma ahead of __VA_ARGS__, if present, according to compiler 234 /// dialect settings. Returns true if the comma is removed. 235 bool MaybeRemoveCommaBeforeVaArgs(SmallVectorImpl<Token> &ResultToks, 236 bool HasPasteOperator, 237 MacroInfo *Macro, unsigned MacroArgNo, 238 Preprocessor &PP); 239 240 void PropagateLineStartLeadingSpaceInfo(Token &Result); 241 }; 242 243 } // namespace clang 244 245 #endif // LLVM_CLANG_LEX_TOKENLEXER_H 246