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 using namespace clang; 17 18 19 /// StartsWithL - Return true if the spelling of this token starts with 'L'. 20 bool TokenConcatenation::StartsWithL(const Token &Tok) const { 21 if (!Tok.needsCleaning()) { 22 SourceManager &SM = PP.getSourceManager(); 23 return *SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())) == 'L'; 24 } 25 26 if (Tok.getLength() < 256) { 27 char Buffer[256]; 28 const char *TokPtr = Buffer; 29 PP.getSpelling(Tok, TokPtr); 30 return TokPtr[0] == 'L'; 31 } 32 33 return PP.getSpelling(Tok)[0] == 'L'; 34 } 35 36 /// IsIdentifierL - Return true if the spelling of this token is literally 37 /// 'L'. 38 bool TokenConcatenation::IsIdentifierL(const Token &Tok) const { 39 if (!Tok.needsCleaning()) { 40 if (Tok.getLength() != 1) 41 return false; 42 SourceManager &SM = PP.getSourceManager(); 43 return *SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())) == 'L'; 44 } 45 46 if (Tok.getLength() < 256) { 47 char Buffer[256]; 48 const char *TokPtr = Buffer; 49 if (PP.getSpelling(Tok, TokPtr) != 1) 50 return false; 51 return TokPtr[0] == 'L'; 52 } 53 54 return PP.getSpelling(Tok) == "L"; 55 } 56 57 TokenConcatenation::TokenConcatenation(Preprocessor &pp) : PP(pp) { 58 memset(TokenInfo, 0, sizeof(TokenInfo)); 59 60 // These tokens have custom code in AvoidConcat. 61 TokenInfo[tok::identifier ] |= aci_custom; 62 TokenInfo[tok::numeric_constant] |= aci_custom_firstchar; 63 TokenInfo[tok::period ] |= aci_custom_firstchar; 64 TokenInfo[tok::amp ] |= aci_custom_firstchar; 65 TokenInfo[tok::plus ] |= aci_custom_firstchar; 66 TokenInfo[tok::minus ] |= aci_custom_firstchar; 67 TokenInfo[tok::slash ] |= aci_custom_firstchar; 68 TokenInfo[tok::less ] |= aci_custom_firstchar; 69 TokenInfo[tok::greater ] |= aci_custom_firstchar; 70 TokenInfo[tok::pipe ] |= aci_custom_firstchar; 71 TokenInfo[tok::percent ] |= aci_custom_firstchar; 72 TokenInfo[tok::colon ] |= aci_custom_firstchar; 73 TokenInfo[tok::hash ] |= aci_custom_firstchar; 74 TokenInfo[tok::arrow ] |= aci_custom_firstchar; 75 76 // These tokens change behavior if followed by an '='. 77 TokenInfo[tok::amp ] |= aci_avoid_equal; // &= 78 TokenInfo[tok::plus ] |= aci_avoid_equal; // += 79 TokenInfo[tok::minus ] |= aci_avoid_equal; // -= 80 TokenInfo[tok::slash ] |= aci_avoid_equal; // /= 81 TokenInfo[tok::less ] |= aci_avoid_equal; // <= 82 TokenInfo[tok::greater ] |= aci_avoid_equal; // >= 83 TokenInfo[tok::pipe ] |= aci_avoid_equal; // |= 84 TokenInfo[tok::percent ] |= aci_avoid_equal; // %= 85 TokenInfo[tok::star ] |= aci_avoid_equal; // *= 86 TokenInfo[tok::exclaim ] |= aci_avoid_equal; // != 87 TokenInfo[tok::lessless ] |= aci_avoid_equal; // <<= 88 TokenInfo[tok::greaterequal] |= aci_avoid_equal; // >>= 89 TokenInfo[tok::caret ] |= aci_avoid_equal; // ^= 90 TokenInfo[tok::equal ] |= aci_avoid_equal; // == 91 } 92 93 /// GetFirstChar - Get the first character of the token \arg Tok, 94 /// avoiding calls to getSpelling where possible. 95 static char GetFirstChar(Preprocessor &PP, const Token &Tok) { 96 if (IdentifierInfo *II = Tok.getIdentifierInfo()) { 97 // Avoid spelling identifiers, the most common form of token. 98 return II->getName()[0]; 99 } else if (!Tok.needsCleaning()) { 100 if (Tok.isLiteral() && Tok.getLiteralData()) { 101 return *Tok.getLiteralData(); 102 } else { 103 SourceManager &SM = PP.getSourceManager(); 104 return *SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())); 105 } 106 } else if (Tok.getLength() < 256) { 107 char Buffer[256]; 108 const char *TokPtr = Buffer; 109 PP.getSpelling(Tok, TokPtr); 110 return TokPtr[0]; 111 } else { 112 return PP.getSpelling(Tok)[0]; 113 } 114 } 115 116 /// AvoidConcat - If printing PrevTok immediately followed by Tok would cause 117 /// the two individual tokens to be lexed as a single token, return true 118 /// (which causes a space to be printed between them). This allows the output 119 /// of -E mode to be lexed to the same token stream as lexing the input 120 /// directly would. 121 /// 122 /// This code must conservatively return true if it doesn't want to be 100% 123 /// accurate. This will cause the output to include extra space characters, 124 /// but the resulting output won't have incorrect concatenations going on. 125 /// Examples include "..", which we print with a space between, because we 126 /// don't want to track enough to tell "x.." from "...". 127 bool TokenConcatenation::AvoidConcat(const Token &PrevTok, 128 const Token &Tok) const { 129 // First, check to see if the tokens were directly adjacent in the original 130 // source. If they were, it must be okay to stick them together: if there 131 // were an issue, the tokens would have been lexed differently. 132 if (PrevTok.getLocation().isFileID() && Tok.getLocation().isFileID() && 133 PrevTok.getLocation().getFileLocWithOffset(PrevTok.getLength()) == 134 Tok.getLocation()) 135 return false; 136 137 tok::TokenKind PrevKind = PrevTok.getKind(); 138 if (PrevTok.getIdentifierInfo()) // Language keyword or named operator. 139 PrevKind = tok::identifier; 140 141 // Look up information on when we should avoid concatenation with prevtok. 142 unsigned ConcatInfo = TokenInfo[PrevKind]; 143 144 // If prevtok never causes a problem for anything after it, return quickly. 145 if (ConcatInfo == 0) return false; 146 147 if (ConcatInfo & aci_avoid_equal) { 148 // If the next token is '=' or '==', avoid concatenation. 149 if (Tok.is(tok::equal) || Tok.is(tok::equalequal)) 150 return true; 151 ConcatInfo &= ~aci_avoid_equal; 152 } 153 154 if (ConcatInfo == 0) return false; 155 156 // Basic algorithm: we look at the first character of the second token, and 157 // determine whether it, if appended to the first token, would form (or 158 // would contribute) to a larger token if concatenated. 159 char FirstChar = 0; 160 if (ConcatInfo & aci_custom) { 161 // If the token does not need to know the first character, don't get it. 162 } else { 163 FirstChar = GetFirstChar(PP, Tok); 164 } 165 166 switch (PrevKind) { 167 default: assert(0 && "InitAvoidConcatTokenInfo built wrong"); 168 case tok::identifier: // id+id or id+number or id+L"foo". 169 // id+'.'... will not append. 170 if (Tok.is(tok::numeric_constant)) 171 return GetFirstChar(PP, Tok) != '.'; 172 173 if (Tok.getIdentifierInfo() || Tok.is(tok::wide_string_literal) /* || 174 Tok.is(tok::wide_char_literal)*/) 175 return true; 176 177 // If this isn't identifier + string, we're done. 178 if (Tok.isNot(tok::char_constant) && Tok.isNot(tok::string_literal)) 179 return false; 180 181 // FIXME: need a wide_char_constant! 182 183 // If the string was a wide string L"foo" or wide char L'f', it would 184 // concat with the previous identifier into fooL"bar". Avoid this. 185 if (StartsWithL(Tok)) 186 return true; 187 188 // Otherwise, this is a narrow character or string. If the *identifier* 189 // is a literal 'L', avoid pasting L "foo" -> L"foo". 190 return IsIdentifierL(PrevTok); 191 case tok::numeric_constant: 192 return isalnum(FirstChar) || Tok.is(tok::numeric_constant) || 193 FirstChar == '+' || FirstChar == '-' || FirstChar == '.'; 194 case tok::period: // ..., .*, .1234 195 return FirstChar == '.' || isdigit(FirstChar) || 196 (PP.getLangOptions().CPlusPlus && FirstChar == '*'); 197 case tok::amp: // && 198 return FirstChar == '&'; 199 case tok::plus: // ++ 200 return FirstChar == '+'; 201 case tok::minus: // --, ->, ->* 202 return FirstChar == '-' || FirstChar == '>'; 203 case tok::slash: //, /*, // 204 return FirstChar == '*' || FirstChar == '/'; 205 case tok::less: // <<, <<=, <:, <% 206 return FirstChar == '<' || FirstChar == ':' || FirstChar == '%'; 207 case tok::greater: // >>, >>= 208 return FirstChar == '>'; 209 case tok::pipe: // || 210 return FirstChar == '|'; 211 case tok::percent: // %>, %: 212 return FirstChar == '>' || FirstChar == ':'; 213 case tok::colon: // ::, :> 214 return FirstChar == '>' || 215 (PP.getLangOptions().CPlusPlus && FirstChar == ':'); 216 case tok::hash: // ##, #@, %:%: 217 return FirstChar == '#' || FirstChar == '@' || FirstChar == '%'; 218 case tok::arrow: // ->* 219 return PP.getLangOptions().CPlusPlus && FirstChar == '*'; 220 } 221 } 222