1 //===--- TokenConcatenation.cpp - Token Concatenation Avoidance -----------===// 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 implements the TokenConcatenation class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "clang/Lex/TokenConcatenation.h" 15 #include "clang/Basic/CharInfo.h" 16 #include "clang/Lex/Preprocessor.h" 17 #include "llvm/Support/ErrorHandling.h" 18 using namespace clang; 19 20 21 /// IsStringPrefix - Return true if Str is a string prefix. 22 /// 'L', 'u', 'U', or 'u8'. Including raw versions. 23 static bool IsStringPrefix(StringRef Str, bool CPlusPlus11) { 24 25 if (Str[0] == 'L' || 26 (CPlusPlus11 && (Str[0] == 'u' || Str[0] == 'U' || Str[0] == 'R'))) { 27 28 if (Str.size() == 1) 29 return true; // "L", "u", "U", and "R" 30 31 // Check for raw flavors. Need to make sure the first character wasn't 32 // already R. Need CPlusPlus11 check for "LR". 33 if (Str[1] == 'R' && Str[0] != 'R' && Str.size() == 2 && CPlusPlus11) 34 return true; // "LR", "uR", "UR" 35 36 // Check for "u8" and "u8R" 37 if (Str[0] == 'u' && Str[1] == '8') { 38 if (Str.size() == 2) return true; // "u8" 39 if (Str.size() == 3 && Str[2] == 'R') return true; // "u8R" 40 } 41 } 42 43 return false; 44 } 45 46 /// IsIdentifierStringPrefix - Return true if the spelling of the token 47 /// is literally 'L', 'u', 'U', or 'u8'. Including raw versions. 48 bool TokenConcatenation::IsIdentifierStringPrefix(const Token &Tok) const { 49 const LangOptions &LangOpts = PP.getLangOpts(); 50 51 if (!Tok.needsCleaning()) { 52 if (Tok.getLength() < 1 || Tok.getLength() > 3) 53 return false; 54 SourceManager &SM = PP.getSourceManager(); 55 const char *Ptr = SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())); 56 return IsStringPrefix(StringRef(Ptr, Tok.getLength()), 57 LangOpts.CPlusPlus11); 58 } 59 60 if (Tok.getLength() < 256) { 61 char Buffer[256]; 62 const char *TokPtr = Buffer; 63 unsigned length = PP.getSpelling(Tok, TokPtr); 64 return IsStringPrefix(StringRef(TokPtr, length), LangOpts.CPlusPlus11); 65 } 66 67 return IsStringPrefix(StringRef(PP.getSpelling(Tok)), LangOpts.CPlusPlus11); 68 } 69 70 TokenConcatenation::TokenConcatenation(Preprocessor &pp) : PP(pp) { 71 memset(TokenInfo, 0, sizeof(TokenInfo)); 72 73 // These tokens have custom code in AvoidConcat. 74 TokenInfo[tok::identifier ] |= aci_custom; 75 TokenInfo[tok::numeric_constant] |= aci_custom_firstchar; 76 TokenInfo[tok::period ] |= aci_custom_firstchar; 77 TokenInfo[tok::amp ] |= aci_custom_firstchar; 78 TokenInfo[tok::plus ] |= aci_custom_firstchar; 79 TokenInfo[tok::minus ] |= aci_custom_firstchar; 80 TokenInfo[tok::slash ] |= aci_custom_firstchar; 81 TokenInfo[tok::less ] |= aci_custom_firstchar; 82 TokenInfo[tok::greater ] |= aci_custom_firstchar; 83 TokenInfo[tok::pipe ] |= aci_custom_firstchar; 84 TokenInfo[tok::percent ] |= aci_custom_firstchar; 85 TokenInfo[tok::colon ] |= aci_custom_firstchar; 86 TokenInfo[tok::hash ] |= aci_custom_firstchar; 87 TokenInfo[tok::arrow ] |= aci_custom_firstchar; 88 89 // These tokens have custom code in C++11 mode. 90 if (PP.getLangOpts().CPlusPlus11) { 91 TokenInfo[tok::string_literal ] |= aci_custom; 92 TokenInfo[tok::wide_string_literal ] |= aci_custom; 93 TokenInfo[tok::utf8_string_literal ] |= aci_custom; 94 TokenInfo[tok::utf16_string_literal] |= aci_custom; 95 TokenInfo[tok::utf32_string_literal] |= aci_custom; 96 TokenInfo[tok::char_constant ] |= aci_custom; 97 TokenInfo[tok::wide_char_constant ] |= aci_custom; 98 TokenInfo[tok::utf16_char_constant ] |= aci_custom; 99 TokenInfo[tok::utf32_char_constant ] |= aci_custom; 100 } 101 102 // These tokens have custom code in C++1z mode. 103 if (PP.getLangOpts().CPlusPlus1z) 104 TokenInfo[tok::utf8_char_constant] |= aci_custom; 105 106 // These tokens change behavior if followed by an '='. 107 TokenInfo[tok::amp ] |= aci_avoid_equal; // &= 108 TokenInfo[tok::plus ] |= aci_avoid_equal; // += 109 TokenInfo[tok::minus ] |= aci_avoid_equal; // -= 110 TokenInfo[tok::slash ] |= aci_avoid_equal; // /= 111 TokenInfo[tok::less ] |= aci_avoid_equal; // <= 112 TokenInfo[tok::greater ] |= aci_avoid_equal; // >= 113 TokenInfo[tok::pipe ] |= aci_avoid_equal; // |= 114 TokenInfo[tok::percent ] |= aci_avoid_equal; // %= 115 TokenInfo[tok::star ] |= aci_avoid_equal; // *= 116 TokenInfo[tok::exclaim ] |= aci_avoid_equal; // != 117 TokenInfo[tok::lessless ] |= aci_avoid_equal; // <<= 118 TokenInfo[tok::greatergreater] |= aci_avoid_equal; // >>= 119 TokenInfo[tok::caret ] |= aci_avoid_equal; // ^= 120 TokenInfo[tok::equal ] |= aci_avoid_equal; // == 121 } 122 123 /// GetFirstChar - Get the first character of the token \arg Tok, 124 /// avoiding calls to getSpelling where possible. 125 static char GetFirstChar(Preprocessor &PP, const Token &Tok) { 126 if (IdentifierInfo *II = Tok.getIdentifierInfo()) { 127 // Avoid spelling identifiers, the most common form of token. 128 return II->getNameStart()[0]; 129 } else if (!Tok.needsCleaning()) { 130 if (Tok.isLiteral() && Tok.getLiteralData()) { 131 return *Tok.getLiteralData(); 132 } else { 133 SourceManager &SM = PP.getSourceManager(); 134 return *SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())); 135 } 136 } else if (Tok.getLength() < 256) { 137 char Buffer[256]; 138 const char *TokPtr = Buffer; 139 PP.getSpelling(Tok, TokPtr); 140 return TokPtr[0]; 141 } else { 142 return PP.getSpelling(Tok)[0]; 143 } 144 } 145 146 /// AvoidConcat - If printing PrevTok immediately followed by Tok would cause 147 /// the two individual tokens to be lexed as a single token, return true 148 /// (which causes a space to be printed between them). This allows the output 149 /// of -E mode to be lexed to the same token stream as lexing the input 150 /// directly would. 151 /// 152 /// This code must conservatively return true if it doesn't want to be 100% 153 /// accurate. This will cause the output to include extra space characters, 154 /// but the resulting output won't have incorrect concatenations going on. 155 /// Examples include "..", which we print with a space between, because we 156 /// don't want to track enough to tell "x.." from "...". 157 bool TokenConcatenation::AvoidConcat(const Token &PrevPrevTok, 158 const Token &PrevTok, 159 const Token &Tok) const { 160 // First, check to see if the tokens were directly adjacent in the original 161 // source. If they were, it must be okay to stick them together: if there 162 // were an issue, the tokens would have been lexed differently. 163 SourceManager &SM = PP.getSourceManager(); 164 SourceLocation PrevSpellLoc = SM.getSpellingLoc(PrevTok.getLocation()); 165 SourceLocation SpellLoc = SM.getSpellingLoc(Tok.getLocation()); 166 if (PrevSpellLoc.getLocWithOffset(PrevTok.getLength()) == SpellLoc) 167 return false; 168 169 tok::TokenKind PrevKind = PrevTok.getKind(); 170 if (!PrevTok.isAnnotation() && PrevTok.getIdentifierInfo()) 171 PrevKind = tok::identifier; // Language keyword or named operator. 172 173 // Look up information on when we should avoid concatenation with prevtok. 174 unsigned ConcatInfo = TokenInfo[PrevKind]; 175 176 // If prevtok never causes a problem for anything after it, return quickly. 177 if (ConcatInfo == 0) return false; 178 179 if (ConcatInfo & aci_avoid_equal) { 180 // If the next token is '=' or '==', avoid concatenation. 181 if (Tok.isOneOf(tok::equal, tok::equalequal)) 182 return true; 183 ConcatInfo &= ~aci_avoid_equal; 184 } 185 if (Tok.isAnnotation()) { 186 // Modules annotation can show up when generated automatically for includes. 187 assert(Tok.isOneOf(tok::annot_module_include, tok::annot_module_begin, 188 tok::annot_module_end) && 189 "unexpected annotation in AvoidConcat"); 190 ConcatInfo = 0; 191 } 192 193 if (ConcatInfo == 0) 194 return false; 195 196 // Basic algorithm: we look at the first character of the second token, and 197 // determine whether it, if appended to the first token, would form (or 198 // would contribute) to a larger token if concatenated. 199 char FirstChar = 0; 200 if (ConcatInfo & aci_custom) { 201 // If the token does not need to know the first character, don't get it. 202 } else { 203 FirstChar = GetFirstChar(PP, Tok); 204 } 205 206 switch (PrevKind) { 207 default: 208 llvm_unreachable("InitAvoidConcatTokenInfo built wrong"); 209 210 case tok::raw_identifier: 211 llvm_unreachable("tok::raw_identifier in non-raw lexing mode!"); 212 213 case tok::string_literal: 214 case tok::wide_string_literal: 215 case tok::utf8_string_literal: 216 case tok::utf16_string_literal: 217 case tok::utf32_string_literal: 218 case tok::char_constant: 219 case tok::wide_char_constant: 220 case tok::utf8_char_constant: 221 case tok::utf16_char_constant: 222 case tok::utf32_char_constant: 223 if (!PP.getLangOpts().CPlusPlus11) 224 return false; 225 226 // In C++11, a string or character literal followed by an identifier is a 227 // single token. 228 if (Tok.getIdentifierInfo()) 229 return true; 230 231 // A ud-suffix is an identifier. If the previous token ends with one, treat 232 // it as an identifier. 233 if (!PrevTok.hasUDSuffix()) 234 return false; 235 // FALL THROUGH. 236 case tok::identifier: // id+id or id+number or id+L"foo". 237 // id+'.'... will not append. 238 if (Tok.is(tok::numeric_constant)) 239 return GetFirstChar(PP, Tok) != '.'; 240 241 if (Tok.getIdentifierInfo() || 242 Tok.isOneOf(tok::wide_string_literal, tok::utf8_string_literal, 243 tok::utf16_string_literal, tok::utf32_string_literal, 244 tok::wide_char_constant, tok::utf8_char_constant, 245 tok::utf16_char_constant, tok::utf32_char_constant)) 246 return true; 247 248 // If this isn't identifier + string, we're done. 249 if (Tok.isNot(tok::char_constant) && Tok.isNot(tok::string_literal)) 250 return false; 251 252 // Otherwise, this is a narrow character or string. If the *identifier* 253 // is a literal 'L', 'u8', 'u' or 'U', avoid pasting L "foo" -> L"foo". 254 return IsIdentifierStringPrefix(PrevTok); 255 256 case tok::numeric_constant: 257 return isPreprocessingNumberBody(FirstChar) || 258 FirstChar == '+' || FirstChar == '-'; 259 case tok::period: // ..., .*, .1234 260 return (FirstChar == '.' && PrevPrevTok.is(tok::period)) || 261 isDigit(FirstChar) || 262 (PP.getLangOpts().CPlusPlus && FirstChar == '*'); 263 case tok::amp: // && 264 return FirstChar == '&'; 265 case tok::plus: // ++ 266 return FirstChar == '+'; 267 case tok::minus: // --, ->, ->* 268 return FirstChar == '-' || FirstChar == '>'; 269 case tok::slash: //, /*, // 270 return FirstChar == '*' || FirstChar == '/'; 271 case tok::less: // <<, <<=, <:, <% 272 return FirstChar == '<' || FirstChar == ':' || FirstChar == '%'; 273 case tok::greater: // >>, >>= 274 return FirstChar == '>'; 275 case tok::pipe: // || 276 return FirstChar == '|'; 277 case tok::percent: // %>, %: 278 return FirstChar == '>' || FirstChar == ':'; 279 case tok::colon: // ::, :> 280 return FirstChar == '>' || 281 (PP.getLangOpts().CPlusPlus && FirstChar == ':'); 282 case tok::hash: // ##, #@, %:%: 283 return FirstChar == '#' || FirstChar == '@' || FirstChar == '%'; 284 case tok::arrow: // ->* 285 return PP.getLangOpts().CPlusPlus && FirstChar == '*'; 286 } 287 } 288
