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/Lex/Preprocessor.h" 16 #include "llvm/Support/ErrorHandling.h" 17 using namespace clang; 18 19 20 /// IsStringPrefix - Return true if Str is a string prefix. 21 /// 'L', 'u', 'U', or 'u8'. Including raw versions. 22 static bool IsStringPrefix(StringRef Str, bool CPlusPlus0x) { 23 24 if (Str[0] == 'L' || 25 (CPlusPlus0x && (Str[0] == 'u' || Str[0] == 'U' || Str[0] == 'R'))) { 26 27 if (Str.size() == 1) 28 return true; // "L", "u", "U", and "R" 29 30 // Check for raw flavors. Need to make sure the first character wasn't 31 // already R. Need CPlusPlus0x check for "LR". 32 if (Str[1] == 'R' && Str[0] != 'R' && Str.size() == 2 && CPlusPlus0x) 33 return true; // "LR", "uR", "UR" 34 35 // Check for "u8" and "u8R" 36 if (Str[0] == 'u' && Str[1] == '8') { 37 if (Str.size() == 2) return true; // "u8" 38 if (Str.size() == 3 && Str[2] == 'R') return true; // "u8R" 39 } 40 } 41 42 return false; 43 } 44 45 /// IsIdentifierStringPrefix - Return true if the spelling of the token 46 /// is literally 'L', 'u', 'U', or 'u8'. Including raw versions. 47 bool TokenConcatenation::IsIdentifierStringPrefix(const Token &Tok) const { 48 const LangOptions &LangOpts = PP.getLangOpts(); 49 50 if (!Tok.needsCleaning()) { 51 if (Tok.getLength() < 1 || Tok.getLength() > 3) 52 return false; 53 SourceManager &SM = PP.getSourceManager(); 54 const char *Ptr = SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())); 55 return IsStringPrefix(StringRef(Ptr, Tok.getLength()), 56 LangOpts.CPlusPlus0x); 57 } 58 59 if (Tok.getLength() < 256) { 60 char Buffer[256]; 61 const char *TokPtr = Buffer; 62 unsigned length = PP.getSpelling(Tok, TokPtr); 63 return IsStringPrefix(StringRef(TokPtr, length), LangOpts.CPlusPlus0x); 64 } 65 66 return IsStringPrefix(StringRef(PP.getSpelling(Tok)), LangOpts.CPlusPlus0x); 67 } 68 69 TokenConcatenation::TokenConcatenation(Preprocessor &pp) : PP(pp) { 70 memset(TokenInfo, 0, sizeof(TokenInfo)); 71 72 // These tokens have custom code in AvoidConcat. 73 TokenInfo[tok::identifier ] |= aci_custom; 74 TokenInfo[tok::numeric_constant] |= aci_custom_firstchar; 75 TokenInfo[tok::period ] |= aci_custom_firstchar; 76 TokenInfo[tok::amp ] |= aci_custom_firstchar; 77 TokenInfo[tok::plus ] |= aci_custom_firstchar; 78 TokenInfo[tok::minus ] |= aci_custom_firstchar; 79 TokenInfo[tok::slash ] |= aci_custom_firstchar; 80 TokenInfo[tok::less ] |= aci_custom_firstchar; 81 TokenInfo[tok::greater ] |= aci_custom_firstchar; 82 TokenInfo[tok::pipe ] |= aci_custom_firstchar; 83 TokenInfo[tok::percent ] |= aci_custom_firstchar; 84 TokenInfo[tok::colon ] |= aci_custom_firstchar; 85 TokenInfo[tok::hash ] |= aci_custom_firstchar; 86 TokenInfo[tok::arrow ] |= aci_custom_firstchar; 87 88 // These tokens have custom code in C++11 mode. 89 if (PP.getLangOpts().CPlusPlus0x) { 90 TokenInfo[tok::string_literal ] |= aci_custom; 91 TokenInfo[tok::wide_string_literal ] |= aci_custom; 92 TokenInfo[tok::utf8_string_literal ] |= aci_custom; 93 TokenInfo[tok::utf16_string_literal] |= aci_custom; 94 TokenInfo[tok::utf32_string_literal] |= aci_custom; 95 TokenInfo[tok::char_constant ] |= aci_custom; 96 TokenInfo[tok::wide_char_constant ] |= aci_custom; 97 TokenInfo[tok::utf16_char_constant ] |= aci_custom; 98 TokenInfo[tok::utf32_char_constant ] |= aci_custom; 99 } 100 101 // These tokens change behavior if followed by an '='. 102 TokenInfo[tok::amp ] |= aci_avoid_equal; // &= 103 TokenInfo[tok::plus ] |= aci_avoid_equal; // += 104 TokenInfo[tok::minus ] |= aci_avoid_equal; // -= 105 TokenInfo[tok::slash ] |= aci_avoid_equal; // /= 106 TokenInfo[tok::less ] |= aci_avoid_equal; // <= 107 TokenInfo[tok::greater ] |= aci_avoid_equal; // >= 108 TokenInfo[tok::pipe ] |= aci_avoid_equal; // |= 109 TokenInfo[tok::percent ] |= aci_avoid_equal; // %= 110 TokenInfo[tok::star ] |= aci_avoid_equal; // *= 111 TokenInfo[tok::exclaim ] |= aci_avoid_equal; // != 112 TokenInfo[tok::lessless ] |= aci_avoid_equal; // <<= 113 TokenInfo[tok::greatergreater] |= aci_avoid_equal; // >>= 114 TokenInfo[tok::caret ] |= aci_avoid_equal; // ^= 115 TokenInfo[tok::equal ] |= aci_avoid_equal; // == 116 } 117 118 /// GetFirstChar - Get the first character of the token \arg Tok, 119 /// avoiding calls to getSpelling where possible. 120 static char GetFirstChar(Preprocessor &PP, const Token &Tok) { 121 if (IdentifierInfo *II = Tok.getIdentifierInfo()) { 122 // Avoid spelling identifiers, the most common form of token. 123 return II->getNameStart()[0]; 124 } else if (!Tok.needsCleaning()) { 125 if (Tok.isLiteral() && Tok.getLiteralData()) { 126 return *Tok.getLiteralData(); 127 } else { 128 SourceManager &SM = PP.getSourceManager(); 129 return *SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())); 130 } 131 } else if (Tok.getLength() < 256) { 132 char Buffer[256]; 133 const char *TokPtr = Buffer; 134 PP.getSpelling(Tok, TokPtr); 135 return TokPtr[0]; 136 } else { 137 return PP.getSpelling(Tok)[0]; 138 } 139 } 140 141 /// AvoidConcat - If printing PrevTok immediately followed by Tok would cause 142 /// the two individual tokens to be lexed as a single token, return true 143 /// (which causes a space to be printed between them). This allows the output 144 /// of -E mode to be lexed to the same token stream as lexing the input 145 /// directly would. 146 /// 147 /// This code must conservatively return true if it doesn't want to be 100% 148 /// accurate. This will cause the output to include extra space characters, 149 /// but the resulting output won't have incorrect concatenations going on. 150 /// Examples include "..", which we print with a space between, because we 151 /// don't want to track enough to tell "x.." from "...". 152 bool TokenConcatenation::AvoidConcat(const Token &PrevPrevTok, 153 const Token &PrevTok, 154 const Token &Tok) const { 155 // First, check to see if the tokens were directly adjacent in the original 156 // source. If they were, it must be okay to stick them together: if there 157 // were an issue, the tokens would have been lexed differently. 158 if (PrevTok.getLocation().isFileID() && Tok.getLocation().isFileID() && 159 PrevTok.getLocation().getLocWithOffset(PrevTok.getLength()) == 160 Tok.getLocation()) 161 return false; 162 163 tok::TokenKind PrevKind = PrevTok.getKind(); 164 if (PrevTok.getIdentifierInfo()) // Language keyword or named operator. 165 PrevKind = tok::identifier; 166 167 // Look up information on when we should avoid concatenation with prevtok. 168 unsigned ConcatInfo = TokenInfo[PrevKind]; 169 170 // If prevtok never causes a problem for anything after it, return quickly. 171 if (ConcatInfo == 0) return false; 172 173 if (ConcatInfo & aci_avoid_equal) { 174 // If the next token is '=' or '==', avoid concatenation. 175 if (Tok.is(tok::equal) || Tok.is(tok::equalequal)) 176 return true; 177 ConcatInfo &= ~aci_avoid_equal; 178 } 179 180 if (ConcatInfo == 0) return false; 181 182 // Basic algorithm: we look at the first character of the second token, and 183 // determine whether it, if appended to the first token, would form (or 184 // would contribute) to a larger token if concatenated. 185 char FirstChar = 0; 186 if (ConcatInfo & aci_custom) { 187 // If the token does not need to know the first character, don't get it. 188 } else { 189 FirstChar = GetFirstChar(PP, Tok); 190 } 191 192 switch (PrevKind) { 193 default: 194 llvm_unreachable("InitAvoidConcatTokenInfo built wrong"); 195 196 case tok::raw_identifier: 197 llvm_unreachable("tok::raw_identifier in non-raw lexing mode!"); 198 199 case tok::string_literal: 200 case tok::wide_string_literal: 201 case tok::utf8_string_literal: 202 case tok::utf16_string_literal: 203 case tok::utf32_string_literal: 204 case tok::char_constant: 205 case tok::wide_char_constant: 206 case tok::utf16_char_constant: 207 case tok::utf32_char_constant: 208 if (!PP.getLangOpts().CPlusPlus0x) 209 return false; 210 211 // In C++11, a string or character literal followed by an identifier is a 212 // single token. 213 if (Tok.getIdentifierInfo()) 214 return true; 215 216 // A ud-suffix is an identifier. If the previous token ends with one, treat 217 // it as an identifier. 218 if (!PrevTok.hasUDSuffix()) 219 return false; 220 // FALL THROUGH. 221 case tok::identifier: // id+id or id+number or id+L"foo". 222 // id+'.'... will not append. 223 if (Tok.is(tok::numeric_constant)) 224 return GetFirstChar(PP, Tok) != '.'; 225 226 if (Tok.getIdentifierInfo() || Tok.is(tok::wide_string_literal) || 227 Tok.is(tok::utf8_string_literal) || Tok.is(tok::utf16_string_literal) || 228 Tok.is(tok::utf32_string_literal) || Tok.is(tok::wide_char_constant) || 229 Tok.is(tok::utf16_char_constant) || Tok.is(tok::utf32_char_constant)) 230 return true; 231 232 // If this isn't identifier + string, we're done. 233 if (Tok.isNot(tok::char_constant) && Tok.isNot(tok::string_literal)) 234 return false; 235 236 // Otherwise, this is a narrow character or string. If the *identifier* 237 // is a literal 'L', 'u8', 'u' or 'U', avoid pasting L "foo" -> L"foo". 238 return IsIdentifierStringPrefix(PrevTok); 239 240 case tok::numeric_constant: 241 return isalnum(FirstChar) || Tok.is(tok::numeric_constant) || 242 FirstChar == '+' || FirstChar == '-' || FirstChar == '.' || 243 (PP.getLangOpts().CPlusPlus0x && FirstChar == '_'); 244 case tok::period: // ..., .*, .1234 245 return (FirstChar == '.' && PrevPrevTok.is(tok::period)) || 246 isdigit(FirstChar) || 247 (PP.getLangOpts().CPlusPlus && FirstChar == '*'); 248 case tok::amp: // && 249 return FirstChar == '&'; 250 case tok::plus: // ++ 251 return FirstChar == '+'; 252 case tok::minus: // --, ->, ->* 253 return FirstChar == '-' || FirstChar == '>'; 254 case tok::slash: //, /*, // 255 return FirstChar == '*' || FirstChar == '/'; 256 case tok::less: // <<, <<=, <:, <% 257 return FirstChar == '<' || FirstChar == ':' || FirstChar == '%'; 258 case tok::greater: // >>, >>= 259 return FirstChar == '>'; 260 case tok::pipe: // || 261 return FirstChar == '|'; 262 case tok::percent: // %>, %: 263 return FirstChar == '>' || FirstChar == ':'; 264 case tok::colon: // ::, :> 265 return FirstChar == '>' || 266 (PP.getLangOpts().CPlusPlus && FirstChar == ':'); 267 case tok::hash: // ##, #@, %:%: 268 return FirstChar == '#' || FirstChar == '@' || FirstChar == '%'; 269 case tok::arrow: // ->* 270 return PP.getLangOpts().CPlusPlus && FirstChar == '*'; 271 } 272 } 273
