1 //===- TokenLexer.cpp - Lex from a token stream ---------------------------===// 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 implements the TokenLexer interface. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "clang/Lex/TokenLexer.h" 14 #include "clang/Basic/Diagnostic.h" 15 #include "clang/Basic/IdentifierTable.h" 16 #include "clang/Basic/LangOptions.h" 17 #include "clang/Basic/SourceLocation.h" 18 #include "clang/Basic/SourceManager.h" 19 #include "clang/Basic/TokenKinds.h" 20 #include "clang/Lex/LexDiagnostic.h" 21 #include "clang/Lex/Lexer.h" 22 #include "clang/Lex/MacroArgs.h" 23 #include "clang/Lex/MacroInfo.h" 24 #include "clang/Lex/Preprocessor.h" 25 #include "clang/Lex/Token.h" 26 #include "clang/Lex/VariadicMacroSupport.h" 27 #include "llvm/ADT/ArrayRef.h" 28 #include "llvm/ADT/SmallString.h" 29 #include "llvm/ADT/SmallVector.h" 30 #include "llvm/ADT/iterator_range.h" 31 #include <cassert> 32 #include <cstring> 33 34 using namespace clang; 35 36 /// Create a TokenLexer for the specified macro with the specified actual 37 /// arguments. Note that this ctor takes ownership of the ActualArgs pointer. 38 void TokenLexer::Init(Token &Tok, SourceLocation ELEnd, MacroInfo *MI, 39 MacroArgs *Actuals) { 40 // If the client is reusing a TokenLexer, make sure to free any memory 41 // associated with it. 42 destroy(); 43 44 Macro = MI; 45 ActualArgs = Actuals; 46 CurTokenIdx = 0; 47 48 ExpandLocStart = Tok.getLocation(); 49 ExpandLocEnd = ELEnd; 50 AtStartOfLine = Tok.isAtStartOfLine(); 51 HasLeadingSpace = Tok.hasLeadingSpace(); 52 NextTokGetsSpace = false; 53 Tokens = &*Macro->tokens_begin(); 54 OwnsTokens = false; 55 DisableMacroExpansion = false; 56 IsReinject = false; 57 NumTokens = Macro->tokens_end()-Macro->tokens_begin(); 58 MacroExpansionStart = SourceLocation(); 59 60 SourceManager &SM = PP.getSourceManager(); 61 MacroStartSLocOffset = SM.getNextLocalOffset(); 62 63 if (NumTokens > 0) { 64 assert(Tokens[0].getLocation().isValid()); 65 assert((Tokens[0].getLocation().isFileID() || Tokens[0].is(tok::comment)) && 66 "Macro defined in macro?"); 67 assert(ExpandLocStart.isValid()); 68 69 // Reserve a source location entry chunk for the length of the macro 70 // definition. Tokens that get lexed directly from the definition will 71 // have their locations pointing inside this chunk. This is to avoid 72 // creating separate source location entries for each token. 73 MacroDefStart = SM.getExpansionLoc(Tokens[0].getLocation()); 74 MacroDefLength = Macro->getDefinitionLength(SM); 75 MacroExpansionStart = SM.createExpansionLoc(MacroDefStart, 76 ExpandLocStart, 77 ExpandLocEnd, 78 MacroDefLength); 79 } 80 81 // If this is a function-like macro, expand the arguments and change 82 // Tokens to point to the expanded tokens. 83 if (Macro->isFunctionLike() && Macro->getNumParams()) 84 ExpandFunctionArguments(); 85 86 // Mark the macro as currently disabled, so that it is not recursively 87 // expanded. The macro must be disabled only after argument pre-expansion of 88 // function-like macro arguments occurs. 89 Macro->DisableMacro(); 90 } 91 92 /// Create a TokenLexer for the specified token stream. This does not 93 /// take ownership of the specified token vector. 94 void TokenLexer::Init(const Token *TokArray, unsigned NumToks, 95 bool disableMacroExpansion, bool ownsTokens, 96 bool isReinject) { 97 assert(!isReinject || disableMacroExpansion); 98 // If the client is reusing a TokenLexer, make sure to free any memory 99 // associated with it. 100 destroy(); 101 102 Macro = nullptr; 103 ActualArgs = nullptr; 104 Tokens = TokArray; 105 OwnsTokens = ownsTokens; 106 DisableMacroExpansion = disableMacroExpansion; 107 IsReinject = isReinject; 108 NumTokens = NumToks; 109 CurTokenIdx = 0; 110 ExpandLocStart = ExpandLocEnd = SourceLocation(); 111 AtStartOfLine = false; 112 HasLeadingSpace = false; 113 NextTokGetsSpace = false; 114 MacroExpansionStart = SourceLocation(); 115 116 // Set HasLeadingSpace/AtStartOfLine so that the first token will be 117 // returned unmodified. 118 if (NumToks != 0) { 119 AtStartOfLine = TokArray[0].isAtStartOfLine(); 120 HasLeadingSpace = TokArray[0].hasLeadingSpace(); 121 } 122 } 123 124 void TokenLexer::destroy() { 125 // If this was a function-like macro that actually uses its arguments, delete 126 // the expanded tokens. 127 if (OwnsTokens) { 128 delete [] Tokens; 129 Tokens = nullptr; 130 OwnsTokens = false; 131 } 132 133 // TokenLexer owns its formal arguments. 134 if (ActualArgs) ActualArgs->destroy(PP); 135 } 136 137 bool TokenLexer::MaybeRemoveCommaBeforeVaArgs( 138 SmallVectorImpl<Token> &ResultToks, bool HasPasteOperator, MacroInfo *Macro, 139 unsigned MacroArgNo, Preprocessor &PP) { 140 // Is the macro argument __VA_ARGS__? 141 if (!Macro->isVariadic() || MacroArgNo != Macro->getNumParams()-1) 142 return false; 143 144 // In Microsoft-compatibility mode, a comma is removed in the expansion 145 // of " ... , __VA_ARGS__ " if __VA_ARGS__ is empty. This extension is 146 // not supported by gcc. 147 if (!HasPasteOperator && !PP.getLangOpts().MSVCCompat) 148 return false; 149 150 // GCC removes the comma in the expansion of " ... , ## __VA_ARGS__ " if 151 // __VA_ARGS__ is empty, but not in strict C99 mode where there are no 152 // named arguments, where it remains. In all other modes, including C99 153 // with GNU extensions, it is removed regardless of named arguments. 154 // Microsoft also appears to support this extension, unofficially. 155 if (PP.getLangOpts().C99 && !PP.getLangOpts().GNUMode 156 && Macro->getNumParams() < 2) 157 return false; 158 159 // Is a comma available to be removed? 160 if (ResultToks.empty() || !ResultToks.back().is(tok::comma)) 161 return false; 162 163 // Issue an extension diagnostic for the paste operator. 164 if (HasPasteOperator) 165 PP.Diag(ResultToks.back().getLocation(), diag::ext_paste_comma); 166 167 // Remove the comma. 168 ResultToks.pop_back(); 169 170 if (!ResultToks.empty()) { 171 // If the comma was right after another paste (e.g. "X##,##__VA_ARGS__"), 172 // then removal of the comma should produce a placemarker token (in C99 173 // terms) which we model by popping off the previous ##, giving us a plain 174 // "X" when __VA_ARGS__ is empty. 175 if (ResultToks.back().is(tok::hashhash)) 176 ResultToks.pop_back(); 177 178 // Remember that this comma was elided. 179 ResultToks.back().setFlag(Token::CommaAfterElided); 180 } 181 182 // Never add a space, even if the comma, ##, or arg had a space. 183 NextTokGetsSpace = false; 184 return true; 185 } 186 187 void TokenLexer::stringifyVAOPTContents( 188 SmallVectorImpl<Token> &ResultToks, const VAOptExpansionContext &VCtx, 189 const SourceLocation VAOPTClosingParenLoc) { 190 const int NumToksPriorToVAOpt = VCtx.getNumberOfTokensPriorToVAOpt(); 191 const unsigned int NumVAOptTokens = ResultToks.size() - NumToksPriorToVAOpt; 192 Token *const VAOPTTokens = 193 NumVAOptTokens ? &ResultToks[NumToksPriorToVAOpt] : nullptr; 194 195 SmallVector<Token, 64> ConcatenatedVAOPTResultToks; 196 // FIXME: Should we keep track within VCtx that we did or didnot 197 // encounter pasting - and only then perform this loop. 198 199 // Perform token pasting (concatenation) prior to stringization. 200 for (unsigned int CurTokenIdx = 0; CurTokenIdx != NumVAOptTokens; 201 ++CurTokenIdx) { 202 if (VAOPTTokens[CurTokenIdx].is(tok::hashhash)) { 203 assert(CurTokenIdx != 0 && 204 "Can not have __VAOPT__ contents begin with a ##"); 205 Token &LHS = VAOPTTokens[CurTokenIdx - 1]; 206 pasteTokens(LHS, llvm::makeArrayRef(VAOPTTokens, NumVAOptTokens), 207 CurTokenIdx); 208 // Replace the token prior to the first ## in this iteration. 209 ConcatenatedVAOPTResultToks.back() = LHS; 210 if (CurTokenIdx == NumVAOptTokens) 211 break; 212 } 213 ConcatenatedVAOPTResultToks.push_back(VAOPTTokens[CurTokenIdx]); 214 } 215 216 ConcatenatedVAOPTResultToks.push_back(VCtx.getEOFTok()); 217 // Get the SourceLocation that represents the start location within 218 // the macro definition that marks where this string is substituted 219 // into: i.e. the __VA_OPT__ and the ')' within the spelling of the 220 // macro definition, and use it to indicate that the stringified token 221 // was generated from that location. 222 const SourceLocation ExpansionLocStartWithinMacro = 223 getExpansionLocForMacroDefLoc(VCtx.getVAOptLoc()); 224 const SourceLocation ExpansionLocEndWithinMacro = 225 getExpansionLocForMacroDefLoc(VAOPTClosingParenLoc); 226 227 Token StringifiedVAOPT = MacroArgs::StringifyArgument( 228 &ConcatenatedVAOPTResultToks[0], PP, VCtx.hasCharifyBefore() /*Charify*/, 229 ExpansionLocStartWithinMacro, ExpansionLocEndWithinMacro); 230 231 if (VCtx.getLeadingSpaceForStringifiedToken()) 232 StringifiedVAOPT.setFlag(Token::LeadingSpace); 233 234 StringifiedVAOPT.setFlag(Token::StringifiedInMacro); 235 // Resize (shrink) the token stream to just capture this stringified token. 236 ResultToks.resize(NumToksPriorToVAOpt + 1); 237 ResultToks.back() = StringifiedVAOPT; 238 } 239 240 /// Expand the arguments of a function-like macro so that we can quickly 241 /// return preexpanded tokens from Tokens. 242 void TokenLexer::ExpandFunctionArguments() { 243 SmallVector<Token, 128> ResultToks; 244 245 // Loop through 'Tokens', expanding them into ResultToks. Keep 246 // track of whether we change anything. If not, no need to keep them. If so, 247 // we install the newly expanded sequence as the new 'Tokens' list. 248 bool MadeChange = false; 249 250 Optional<bool> CalledWithVariadicArguments; 251 252 VAOptExpansionContext VCtx(PP); 253 254 for (unsigned I = 0, E = NumTokens; I != E; ++I) { 255 const Token &CurTok = Tokens[I]; 256 // We don't want a space for the next token after a paste 257 // operator. In valid code, the token will get smooshed onto the 258 // preceding one anyway. In assembler-with-cpp mode, invalid 259 // pastes are allowed through: in this case, we do not want the 260 // extra whitespace to be added. For example, we want ". ## foo" 261 // -> ".foo" not ". foo". 262 if (I != 0 && !Tokens[I-1].is(tok::hashhash) && CurTok.hasLeadingSpace()) 263 NextTokGetsSpace = true; 264 265 if (VCtx.isVAOptToken(CurTok)) { 266 MadeChange = true; 267 assert(Tokens[I + 1].is(tok::l_paren) && 268 "__VA_OPT__ must be followed by '('"); 269 270 ++I; // Skip the l_paren 271 VCtx.sawVAOptFollowedByOpeningParens(CurTok.getLocation(), 272 ResultToks.size()); 273 274 continue; 275 } 276 277 // We have entered into the __VA_OPT__ context, so handle tokens 278 // appropriately. 279 if (VCtx.isInVAOpt()) { 280 // If we are about to process a token that is either an argument to 281 // __VA_OPT__ or its closing rparen, then: 282 // 1) If the token is the closing rparen that exits us out of __VA_OPT__, 283 // perform any necessary stringification or placemarker processing, 284 // and/or skip to the next token. 285 // 2) else if macro was invoked without variadic arguments skip this 286 // token. 287 // 3) else (macro was invoked with variadic arguments) process the token 288 // normally. 289 290 if (Tokens[I].is(tok::l_paren)) 291 VCtx.sawOpeningParen(Tokens[I].getLocation()); 292 // Continue skipping tokens within __VA_OPT__ if the macro was not 293 // called with variadic arguments, else let the rest of the loop handle 294 // this token. Note sawClosingParen() returns true only if the r_paren matches 295 // the closing r_paren of the __VA_OPT__. 296 if (!Tokens[I].is(tok::r_paren) || !VCtx.sawClosingParen()) { 297 // Lazily expand __VA_ARGS__ when we see the first __VA_OPT__. 298 if (!CalledWithVariadicArguments.hasValue()) { 299 CalledWithVariadicArguments = 300 ActualArgs->invokedWithVariadicArgument(Macro, PP); 301 } 302 if (!*CalledWithVariadicArguments) { 303 // Skip this token. 304 continue; 305 } 306 // ... else the macro was called with variadic arguments, and we do not 307 // have a closing rparen - so process this token normally. 308 } else { 309 // Current token is the closing r_paren which marks the end of the 310 // __VA_OPT__ invocation, so handle any place-marker pasting (if 311 // empty) by removing hashhash either before (if exists) or after. And 312 // also stringify the entire contents if VAOPT was preceded by a hash, 313 // but do so only after any token concatenation that needs to occur 314 // within the contents of VAOPT. 315 316 if (VCtx.hasStringifyOrCharifyBefore()) { 317 // Replace all the tokens just added from within VAOPT into a single 318 // stringified token. This requires token-pasting to eagerly occur 319 // within these tokens. If either the contents of VAOPT were empty 320 // or the macro wasn't called with any variadic arguments, the result 321 // is a token that represents an empty string. 322 stringifyVAOPTContents(ResultToks, VCtx, 323 /*ClosingParenLoc*/ Tokens[I].getLocation()); 324 325 } else if (/*No tokens within VAOPT*/ 326 ResultToks.size() == VCtx.getNumberOfTokensPriorToVAOpt()) { 327 // Treat VAOPT as a placemarker token. Eat either the '##' before the 328 // RHS/VAOPT (if one exists, suggesting that the LHS (if any) to that 329 // hashhash was not a placemarker) or the '##' 330 // after VAOPT, but not both. 331 332 if (ResultToks.size() && ResultToks.back().is(tok::hashhash)) { 333 ResultToks.pop_back(); 334 } else if ((I + 1 != E) && Tokens[I + 1].is(tok::hashhash)) { 335 ++I; // Skip the following hashhash. 336 } 337 } else { 338 // If there's a ## before the __VA_OPT__, we might have discovered 339 // that the __VA_OPT__ begins with a placeholder. We delay action on 340 // that to now to avoid messing up our stashed count of tokens before 341 // __VA_OPT__. 342 if (VCtx.beginsWithPlaceholder()) { 343 assert(VCtx.getNumberOfTokensPriorToVAOpt() > 0 && 344 ResultToks.size() >= VCtx.getNumberOfTokensPriorToVAOpt() && 345 ResultToks[VCtx.getNumberOfTokensPriorToVAOpt() - 1].is( 346 tok::hashhash) && 347 "no token paste before __VA_OPT__"); 348 ResultToks.erase(ResultToks.begin() + 349 VCtx.getNumberOfTokensPriorToVAOpt() - 1); 350 } 351 // If the expansion of __VA_OPT__ ends with a placeholder, eat any 352 // following '##' token. 353 if (VCtx.endsWithPlaceholder() && I + 1 != E && 354 Tokens[I + 1].is(tok::hashhash)) { 355 ++I; 356 } 357 } 358 VCtx.reset(); 359 // We processed __VA_OPT__'s closing paren (and the exit out of 360 // __VA_OPT__), so skip to the next token. 361 continue; 362 } 363 } 364 365 // If we found the stringify operator, get the argument stringified. The 366 // preprocessor already verified that the following token is a macro 367 // parameter or __VA_OPT__ when the #define was lexed. 368 369 if (CurTok.isOneOf(tok::hash, tok::hashat)) { 370 int ArgNo = Macro->getParameterNum(Tokens[I+1].getIdentifierInfo()); 371 assert((ArgNo != -1 || VCtx.isVAOptToken(Tokens[I + 1])) && 372 "Token following # is not an argument or __VA_OPT__!"); 373 374 if (ArgNo == -1) { 375 // Handle the __VA_OPT__ case. 376 VCtx.sawHashOrHashAtBefore(NextTokGetsSpace, 377 CurTok.is(tok::hashat)); 378 continue; 379 } 380 // Else handle the simple argument case. 381 SourceLocation ExpansionLocStart = 382 getExpansionLocForMacroDefLoc(CurTok.getLocation()); 383 SourceLocation ExpansionLocEnd = 384 getExpansionLocForMacroDefLoc(Tokens[I+1].getLocation()); 385 386 Token Res; 387 if (CurTok.is(tok::hash)) // Stringify 388 Res = ActualArgs->getStringifiedArgument(ArgNo, PP, 389 ExpansionLocStart, 390 ExpansionLocEnd); 391 else { 392 // 'charify': don't bother caching these. 393 Res = MacroArgs::StringifyArgument(ActualArgs->getUnexpArgument(ArgNo), 394 PP, true, 395 ExpansionLocStart, 396 ExpansionLocEnd); 397 } 398 Res.setFlag(Token::StringifiedInMacro); 399 400 // The stringified/charified string leading space flag gets set to match 401 // the #/#@ operator. 402 if (NextTokGetsSpace) 403 Res.setFlag(Token::LeadingSpace); 404 405 ResultToks.push_back(Res); 406 MadeChange = true; 407 ++I; // Skip arg name. 408 NextTokGetsSpace = false; 409 continue; 410 } 411 412 // Find out if there is a paste (##) operator before or after the token. 413 bool NonEmptyPasteBefore = 414 !ResultToks.empty() && ResultToks.back().is(tok::hashhash); 415 bool PasteBefore = I != 0 && Tokens[I-1].is(tok::hashhash); 416 bool PasteAfter = I+1 != E && Tokens[I+1].is(tok::hashhash); 417 bool RParenAfter = I+1 != E && Tokens[I+1].is(tok::r_paren); 418 419 assert((!NonEmptyPasteBefore || PasteBefore || VCtx.isInVAOpt()) && 420 "unexpected ## in ResultToks"); 421 422 // Otherwise, if this is not an argument token, just add the token to the 423 // output buffer. 424 IdentifierInfo *II = CurTok.getIdentifierInfo(); 425 int ArgNo = II ? Macro->getParameterNum(II) : -1; 426 if (ArgNo == -1) { 427 // This isn't an argument, just add it. 428 ResultToks.push_back(CurTok); 429 430 if (NextTokGetsSpace) { 431 ResultToks.back().setFlag(Token::LeadingSpace); 432 NextTokGetsSpace = false; 433 } else if (PasteBefore && !NonEmptyPasteBefore) 434 ResultToks.back().clearFlag(Token::LeadingSpace); 435 436 continue; 437 } 438 439 // An argument is expanded somehow, the result is different than the 440 // input. 441 MadeChange = true; 442 443 // Otherwise, this is a use of the argument. 444 445 // In Microsoft mode, remove the comma before __VA_ARGS__ to ensure there 446 // are no trailing commas if __VA_ARGS__ is empty. 447 if (!PasteBefore && ActualArgs->isVarargsElidedUse() && 448 MaybeRemoveCommaBeforeVaArgs(ResultToks, 449 /*HasPasteOperator=*/false, 450 Macro, ArgNo, PP)) 451 continue; 452 453 // If it is not the LHS/RHS of a ## operator, we must pre-expand the 454 // argument and substitute the expanded tokens into the result. This is 455 // C99 6.10.3.1p1. 456 if (!PasteBefore && !PasteAfter) { 457 const Token *ResultArgToks; 458 459 // Only preexpand the argument if it could possibly need it. This 460 // avoids some work in common cases. 461 const Token *ArgTok = ActualArgs->getUnexpArgument(ArgNo); 462 if (ActualArgs->ArgNeedsPreexpansion(ArgTok, PP)) 463 ResultArgToks = &ActualArgs->getPreExpArgument(ArgNo, PP)[0]; 464 else 465 ResultArgToks = ArgTok; // Use non-preexpanded tokens. 466 467 // If the arg token expanded into anything, append it. 468 if (ResultArgToks->isNot(tok::eof)) { 469 size_t FirstResult = ResultToks.size(); 470 unsigned NumToks = MacroArgs::getArgLength(ResultArgToks); 471 ResultToks.append(ResultArgToks, ResultArgToks+NumToks); 472 473 // In Microsoft-compatibility mode, we follow MSVC's preprocessing 474 // behavior by not considering single commas from nested macro 475 // expansions as argument separators. Set a flag on the token so we can 476 // test for this later when the macro expansion is processed. 477 if (PP.getLangOpts().MSVCCompat && NumToks == 1 && 478 ResultToks.back().is(tok::comma)) 479 ResultToks.back().setFlag(Token::IgnoredComma); 480 481 // If the '##' came from expanding an argument, turn it into 'unknown' 482 // to avoid pasting. 483 for (Token &Tok : llvm::make_range(ResultToks.begin() + FirstResult, 484 ResultToks.end())) { 485 if (Tok.is(tok::hashhash)) 486 Tok.setKind(tok::unknown); 487 } 488 489 if(ExpandLocStart.isValid()) { 490 updateLocForMacroArgTokens(CurTok.getLocation(), 491 ResultToks.begin()+FirstResult, 492 ResultToks.end()); 493 } 494 495 // If any tokens were substituted from the argument, the whitespace 496 // before the first token should match the whitespace of the arg 497 // identifier. 498 ResultToks[FirstResult].setFlagValue(Token::LeadingSpace, 499 NextTokGetsSpace); 500 ResultToks[FirstResult].setFlagValue(Token::StartOfLine, false); 501 NextTokGetsSpace = false; 502 } else { 503 // We're creating a placeholder token. Usually this doesn't matter, 504 // but it can affect paste behavior when at the start or end of a 505 // __VA_OPT__. 506 if (NonEmptyPasteBefore) { 507 // We're imagining a placeholder token is inserted here. If this is 508 // the first token in a __VA_OPT__ after a ##, delete the ##. 509 assert(VCtx.isInVAOpt() && "should only happen inside a __VA_OPT__"); 510 VCtx.hasPlaceholderAfterHashhashAtStart(); 511 } 512 if (RParenAfter) 513 VCtx.hasPlaceholderBeforeRParen(); 514 } 515 continue; 516 } 517 518 // Okay, we have a token that is either the LHS or RHS of a paste (##) 519 // argument. It gets substituted as its non-pre-expanded tokens. 520 const Token *ArgToks = ActualArgs->getUnexpArgument(ArgNo); 521 unsigned NumToks = MacroArgs::getArgLength(ArgToks); 522 if (NumToks) { // Not an empty argument? 523 bool VaArgsPseudoPaste = false; 524 // If this is the GNU ", ## __VA_ARGS__" extension, and we just learned 525 // that __VA_ARGS__ expands to multiple tokens, avoid a pasting error when 526 // the expander tries to paste ',' with the first token of the __VA_ARGS__ 527 // expansion. 528 if (NonEmptyPasteBefore && ResultToks.size() >= 2 && 529 ResultToks[ResultToks.size()-2].is(tok::comma) && 530 (unsigned)ArgNo == Macro->getNumParams()-1 && 531 Macro->isVariadic()) { 532 VaArgsPseudoPaste = true; 533 // Remove the paste operator, report use of the extension. 534 PP.Diag(ResultToks.pop_back_val().getLocation(), diag::ext_paste_comma); 535 } 536 537 ResultToks.append(ArgToks, ArgToks+NumToks); 538 539 // If the '##' came from expanding an argument, turn it into 'unknown' 540 // to avoid pasting. 541 for (Token &Tok : llvm::make_range(ResultToks.end() - NumToks, 542 ResultToks.end())) { 543 if (Tok.is(tok::hashhash)) 544 Tok.setKind(tok::unknown); 545 } 546 547 if (ExpandLocStart.isValid()) { 548 updateLocForMacroArgTokens(CurTok.getLocation(), 549 ResultToks.end()-NumToks, ResultToks.end()); 550 } 551 552 // Transfer the leading whitespace information from the token 553 // (the macro argument) onto the first token of the 554 // expansion. Note that we don't do this for the GNU 555 // pseudo-paste extension ", ## __VA_ARGS__". 556 if (!VaArgsPseudoPaste) { 557 ResultToks[ResultToks.size() - NumToks].setFlagValue(Token::StartOfLine, 558 false); 559 ResultToks[ResultToks.size() - NumToks].setFlagValue( 560 Token::LeadingSpace, NextTokGetsSpace); 561 } 562 563 NextTokGetsSpace = false; 564 continue; 565 } 566 567 // If an empty argument is on the LHS or RHS of a paste, the standard (C99 568 // 6.10.3.3p2,3) calls for a bunch of placemarker stuff to occur. We 569 // implement this by eating ## operators when a LHS or RHS expands to 570 // empty. 571 if (PasteAfter) { 572 // Discard the argument token and skip (don't copy to the expansion 573 // buffer) the paste operator after it. 574 ++I; 575 continue; 576 } 577 578 if (RParenAfter) 579 VCtx.hasPlaceholderBeforeRParen(); 580 581 // If this is on the RHS of a paste operator, we've already copied the 582 // paste operator to the ResultToks list, unless the LHS was empty too. 583 // Remove it. 584 assert(PasteBefore); 585 if (NonEmptyPasteBefore) { 586 assert(ResultToks.back().is(tok::hashhash)); 587 // Do not remove the paste operator if it is the one before __VA_OPT__ 588 // (and we are still processing tokens within VA_OPT). We handle the case 589 // of removing the paste operator if __VA_OPT__ reduces to the notional 590 // placemarker above when we encounter the closing paren of VA_OPT. 591 if (!VCtx.isInVAOpt() || 592 ResultToks.size() > VCtx.getNumberOfTokensPriorToVAOpt()) 593 ResultToks.pop_back(); 594 else 595 VCtx.hasPlaceholderAfterHashhashAtStart(); 596 } 597 598 // If this is the __VA_ARGS__ token, and if the argument wasn't provided, 599 // and if the macro had at least one real argument, and if the token before 600 // the ## was a comma, remove the comma. This is a GCC extension which is 601 // disabled when using -std=c99. 602 if (ActualArgs->isVarargsElidedUse()) 603 MaybeRemoveCommaBeforeVaArgs(ResultToks, 604 /*HasPasteOperator=*/true, 605 Macro, ArgNo, PP); 606 } 607 608 // If anything changed, install this as the new Tokens list. 609 if (MadeChange) { 610 assert(!OwnsTokens && "This would leak if we already own the token list"); 611 // This is deleted in the dtor. 612 NumTokens = ResultToks.size(); 613 // The tokens will be added to Preprocessor's cache and will be removed 614 // when this TokenLexer finishes lexing them. 615 Tokens = PP.cacheMacroExpandedTokens(this, ResultToks); 616 617 // The preprocessor cache of macro expanded tokens owns these tokens,not us. 618 OwnsTokens = false; 619 } 620 } 621 622 /// Checks if two tokens form wide string literal. 623 static bool isWideStringLiteralFromMacro(const Token &FirstTok, 624 const Token &SecondTok) { 625 return FirstTok.is(tok::identifier) && 626 FirstTok.getIdentifierInfo()->isStr("L") && SecondTok.isLiteral() && 627 SecondTok.stringifiedInMacro(); 628 } 629 630 /// Lex - Lex and return a token from this macro stream. 631 bool TokenLexer::Lex(Token &Tok) { 632 // Lexing off the end of the macro, pop this macro off the expansion stack. 633 if (isAtEnd()) { 634 // If this is a macro (not a token stream), mark the macro enabled now 635 // that it is no longer being expanded. 636 if (Macro) Macro->EnableMacro(); 637 638 Tok.startToken(); 639 Tok.setFlagValue(Token::StartOfLine , AtStartOfLine); 640 Tok.setFlagValue(Token::LeadingSpace, HasLeadingSpace || NextTokGetsSpace); 641 if (CurTokenIdx == 0) 642 Tok.setFlag(Token::LeadingEmptyMacro); 643 return PP.HandleEndOfTokenLexer(Tok); 644 } 645 646 SourceManager &SM = PP.getSourceManager(); 647 648 // If this is the first token of the expanded result, we inherit spacing 649 // properties later. 650 bool isFirstToken = CurTokenIdx == 0; 651 652 // Get the next token to return. 653 Tok = Tokens[CurTokenIdx++]; 654 if (IsReinject) 655 Tok.setFlag(Token::IsReinjected); 656 657 bool TokenIsFromPaste = false; 658 659 // If this token is followed by a token paste (##) operator, paste the tokens! 660 // Note that ## is a normal token when not expanding a macro. 661 if (!isAtEnd() && Macro && 662 (Tokens[CurTokenIdx].is(tok::hashhash) || 663 // Special processing of L#x macros in -fms-compatibility mode. 664 // Microsoft compiler is able to form a wide string literal from 665 // 'L#macro_arg' construct in a function-like macro. 666 (PP.getLangOpts().MSVCCompat && 667 isWideStringLiteralFromMacro(Tok, Tokens[CurTokenIdx])))) { 668 // When handling the microsoft /##/ extension, the final token is 669 // returned by pasteTokens, not the pasted token. 670 if (pasteTokens(Tok)) 671 return true; 672 673 TokenIsFromPaste = true; 674 } 675 676 // The token's current location indicate where the token was lexed from. We 677 // need this information to compute the spelling of the token, but any 678 // diagnostics for the expanded token should appear as if they came from 679 // ExpansionLoc. Pull this information together into a new SourceLocation 680 // that captures all of this. 681 if (ExpandLocStart.isValid() && // Don't do this for token streams. 682 // Check that the token's location was not already set properly. 683 SM.isBeforeInSLocAddrSpace(Tok.getLocation(), MacroStartSLocOffset)) { 684 SourceLocation instLoc; 685 if (Tok.is(tok::comment)) { 686 instLoc = SM.createExpansionLoc(Tok.getLocation(), 687 ExpandLocStart, 688 ExpandLocEnd, 689 Tok.getLength()); 690 } else { 691 instLoc = getExpansionLocForMacroDefLoc(Tok.getLocation()); 692 } 693 694 Tok.setLocation(instLoc); 695 } 696 697 // If this is the first token, set the lexical properties of the token to 698 // match the lexical properties of the macro identifier. 699 if (isFirstToken) { 700 Tok.setFlagValue(Token::StartOfLine , AtStartOfLine); 701 Tok.setFlagValue(Token::LeadingSpace, HasLeadingSpace); 702 } else { 703 // If this is not the first token, we may still need to pass through 704 // leading whitespace if we've expanded a macro. 705 if (AtStartOfLine) Tok.setFlag(Token::StartOfLine); 706 if (HasLeadingSpace) Tok.setFlag(Token::LeadingSpace); 707 } 708 AtStartOfLine = false; 709 HasLeadingSpace = false; 710 711 // Handle recursive expansion! 712 if (!Tok.isAnnotation() && Tok.getIdentifierInfo() != nullptr) { 713 // Change the kind of this identifier to the appropriate token kind, e.g. 714 // turning "for" into a keyword. 715 IdentifierInfo *II = Tok.getIdentifierInfo(); 716 Tok.setKind(II->getTokenID()); 717 718 // If this identifier was poisoned and from a paste, emit an error. This 719 // won't be handled by Preprocessor::HandleIdentifier because this is coming 720 // from a macro expansion. 721 if (II->isPoisoned() && TokenIsFromPaste) { 722 PP.HandlePoisonedIdentifier(Tok); 723 } 724 725 if (!DisableMacroExpansion && II->isHandleIdentifierCase()) 726 return PP.HandleIdentifier(Tok); 727 } 728 729 // Otherwise, return a normal token. 730 return true; 731 } 732 733 bool TokenLexer::pasteTokens(Token &Tok) { 734 return pasteTokens(Tok, llvm::makeArrayRef(Tokens, NumTokens), CurTokenIdx); 735 } 736 737 /// LHSTok is the LHS of a ## operator, and CurTokenIdx is the ## 738 /// operator. Read the ## and RHS, and paste the LHS/RHS together. If there 739 /// are more ## after it, chomp them iteratively. Return the result as LHSTok. 740 /// If this returns true, the caller should immediately return the token. 741 bool TokenLexer::pasteTokens(Token &LHSTok, ArrayRef<Token> TokenStream, 742 unsigned int &CurIdx) { 743 assert(CurIdx > 0 && "## can not be the first token within tokens"); 744 assert((TokenStream[CurIdx].is(tok::hashhash) || 745 (PP.getLangOpts().MSVCCompat && 746 isWideStringLiteralFromMacro(LHSTok, TokenStream[CurIdx]))) && 747 "Token at this Index must be ## or part of the MSVC 'L " 748 "#macro-arg' pasting pair"); 749 750 // MSVC: If previous token was pasted, this must be a recovery from an invalid 751 // paste operation. Ignore spaces before this token to mimic MSVC output. 752 // Required for generating valid UUID strings in some MS headers. 753 if (PP.getLangOpts().MicrosoftExt && (CurIdx >= 2) && 754 TokenStream[CurIdx - 2].is(tok::hashhash)) 755 LHSTok.clearFlag(Token::LeadingSpace); 756 757 SmallString<128> Buffer; 758 const char *ResultTokStrPtr = nullptr; 759 SourceLocation StartLoc = LHSTok.getLocation(); 760 SourceLocation PasteOpLoc; 761 762 auto IsAtEnd = [&TokenStream, &CurIdx] { 763 return TokenStream.size() == CurIdx; 764 }; 765 766 do { 767 // Consume the ## operator if any. 768 PasteOpLoc = TokenStream[CurIdx].getLocation(); 769 if (TokenStream[CurIdx].is(tok::hashhash)) 770 ++CurIdx; 771 assert(!IsAtEnd() && "No token on the RHS of a paste operator!"); 772 773 // Get the RHS token. 774 const Token &RHS = TokenStream[CurIdx]; 775 776 // Allocate space for the result token. This is guaranteed to be enough for 777 // the two tokens. 778 Buffer.resize(LHSTok.getLength() + RHS.getLength()); 779 780 // Get the spelling of the LHS token in Buffer. 781 const char *BufPtr = &Buffer[0]; 782 bool Invalid = false; 783 unsigned LHSLen = PP.getSpelling(LHSTok, BufPtr, &Invalid); 784 if (BufPtr != &Buffer[0]) // Really, we want the chars in Buffer! 785 memcpy(&Buffer[0], BufPtr, LHSLen); 786 if (Invalid) 787 return true; 788 789 BufPtr = Buffer.data() + LHSLen; 790 unsigned RHSLen = PP.getSpelling(RHS, BufPtr, &Invalid); 791 if (Invalid) 792 return true; 793 if (RHSLen && BufPtr != &Buffer[LHSLen]) 794 // Really, we want the chars in Buffer! 795 memcpy(&Buffer[LHSLen], BufPtr, RHSLen); 796 797 // Trim excess space. 798 Buffer.resize(LHSLen+RHSLen); 799 800 // Plop the pasted result (including the trailing newline and null) into a 801 // scratch buffer where we can lex it. 802 Token ResultTokTmp; 803 ResultTokTmp.startToken(); 804 805 // Claim that the tmp token is a string_literal so that we can get the 806 // character pointer back from CreateString in getLiteralData(). 807 ResultTokTmp.setKind(tok::string_literal); 808 PP.CreateString(Buffer, ResultTokTmp); 809 SourceLocation ResultTokLoc = ResultTokTmp.getLocation(); 810 ResultTokStrPtr = ResultTokTmp.getLiteralData(); 811 812 // Lex the resultant pasted token into Result. 813 Token Result; 814 815 if (LHSTok.isAnyIdentifier() && RHS.isAnyIdentifier()) { 816 // Common paste case: identifier+identifier = identifier. Avoid creating 817 // a lexer and other overhead. 818 PP.IncrementPasteCounter(true); 819 Result.startToken(); 820 Result.setKind(tok::raw_identifier); 821 Result.setRawIdentifierData(ResultTokStrPtr); 822 Result.setLocation(ResultTokLoc); 823 Result.setLength(LHSLen+RHSLen); 824 } else { 825 PP.IncrementPasteCounter(false); 826 827 assert(ResultTokLoc.isFileID() && 828 "Should be a raw location into scratch buffer"); 829 SourceManager &SourceMgr = PP.getSourceManager(); 830 FileID LocFileID = SourceMgr.getFileID(ResultTokLoc); 831 832 bool Invalid = false; 833 const char *ScratchBufStart 834 = SourceMgr.getBufferData(LocFileID, &Invalid).data(); 835 if (Invalid) 836 return false; 837 838 // Make a lexer to lex this string from. Lex just this one token. 839 // Make a lexer object so that we lex and expand the paste result. 840 Lexer TL(SourceMgr.getLocForStartOfFile(LocFileID), 841 PP.getLangOpts(), ScratchBufStart, 842 ResultTokStrPtr, ResultTokStrPtr+LHSLen+RHSLen); 843 844 // Lex a token in raw mode. This way it won't look up identifiers 845 // automatically, lexing off the end will return an eof token, and 846 // warnings are disabled. This returns true if the result token is the 847 // entire buffer. 848 bool isInvalid = !TL.LexFromRawLexer(Result); 849 850 // If we got an EOF token, we didn't form even ONE token. For example, we 851 // did "/ ## /" to get "//". 852 isInvalid |= Result.is(tok::eof); 853 854 // If pasting the two tokens didn't form a full new token, this is an 855 // error. This occurs with "x ## +" and other stuff. Return with LHSTok 856 // unmodified and with RHS as the next token to lex. 857 if (isInvalid) { 858 // Explicitly convert the token location to have proper expansion 859 // information so that the user knows where it came from. 860 SourceManager &SM = PP.getSourceManager(); 861 SourceLocation Loc = 862 SM.createExpansionLoc(PasteOpLoc, ExpandLocStart, ExpandLocEnd, 2); 863 864 // Test for the Microsoft extension of /##/ turning into // here on the 865 // error path. 866 if (PP.getLangOpts().MicrosoftExt && LHSTok.is(tok::slash) && 867 RHS.is(tok::slash)) { 868 HandleMicrosoftCommentPaste(LHSTok, Loc); 869 return true; 870 } 871 872 // Do not emit the error when preprocessing assembler code. 873 if (!PP.getLangOpts().AsmPreprocessor) { 874 // If we're in microsoft extensions mode, downgrade this from a hard 875 // error to an extension that defaults to an error. This allows 876 // disabling it. 877 PP.Diag(Loc, PP.getLangOpts().MicrosoftExt ? diag::ext_pp_bad_paste_ms 878 : diag::err_pp_bad_paste) 879 << Buffer; 880 } 881 882 // An error has occurred so exit loop. 883 break; 884 } 885 886 // Turn ## into 'unknown' to avoid # ## # from looking like a paste 887 // operator. 888 if (Result.is(tok::hashhash)) 889 Result.setKind(tok::unknown); 890 } 891 892 // Transfer properties of the LHS over the Result. 893 Result.setFlagValue(Token::StartOfLine , LHSTok.isAtStartOfLine()); 894 Result.setFlagValue(Token::LeadingSpace, LHSTok.hasLeadingSpace()); 895 896 // Finally, replace LHS with the result, consume the RHS, and iterate. 897 ++CurIdx; 898 LHSTok = Result; 899 } while (!IsAtEnd() && TokenStream[CurIdx].is(tok::hashhash)); 900 901 SourceLocation EndLoc = TokenStream[CurIdx - 1].getLocation(); 902 903 // The token's current location indicate where the token was lexed from. We 904 // need this information to compute the spelling of the token, but any 905 // diagnostics for the expanded token should appear as if the token was 906 // expanded from the full ## expression. Pull this information together into 907 // a new SourceLocation that captures all of this. 908 SourceManager &SM = PP.getSourceManager(); 909 if (StartLoc.isFileID()) 910 StartLoc = getExpansionLocForMacroDefLoc(StartLoc); 911 if (EndLoc.isFileID()) 912 EndLoc = getExpansionLocForMacroDefLoc(EndLoc); 913 FileID MacroFID = SM.getFileID(MacroExpansionStart); 914 while (SM.getFileID(StartLoc) != MacroFID) 915 StartLoc = SM.getImmediateExpansionRange(StartLoc).getBegin(); 916 while (SM.getFileID(EndLoc) != MacroFID) 917 EndLoc = SM.getImmediateExpansionRange(EndLoc).getEnd(); 918 919 LHSTok.setLocation(SM.createExpansionLoc(LHSTok.getLocation(), StartLoc, EndLoc, 920 LHSTok.getLength())); 921 922 // Now that we got the result token, it will be subject to expansion. Since 923 // token pasting re-lexes the result token in raw mode, identifier information 924 // isn't looked up. As such, if the result is an identifier, look up id info. 925 if (LHSTok.is(tok::raw_identifier)) { 926 // Look up the identifier info for the token. We disabled identifier lookup 927 // by saying we're skipping contents, so we need to do this manually. 928 PP.LookUpIdentifierInfo(LHSTok); 929 } 930 return false; 931 } 932 933 /// isNextTokenLParen - If the next token lexed will pop this macro off the 934 /// expansion stack, return 2. If the next unexpanded token is a '(', return 935 /// 1, otherwise return 0. 936 unsigned TokenLexer::isNextTokenLParen() const { 937 // Out of tokens? 938 if (isAtEnd()) 939 return 2; 940 return Tokens[CurTokenIdx].is(tok::l_paren); 941 } 942 943 /// isParsingPreprocessorDirective - Return true if we are in the middle of a 944 /// preprocessor directive. 945 bool TokenLexer::isParsingPreprocessorDirective() const { 946 return Tokens[NumTokens-1].is(tok::eod) && !isAtEnd(); 947 } 948 949 /// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes 950 /// together to form a comment that comments out everything in the current 951 /// macro, other active macros, and anything left on the current physical 952 /// source line of the expanded buffer. Handle this by returning the 953 /// first token on the next line. 954 void TokenLexer::HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc) { 955 PP.Diag(OpLoc, diag::ext_comment_paste_microsoft); 956 957 // We 'comment out' the rest of this macro by just ignoring the rest of the 958 // tokens that have not been lexed yet, if any. 959 960 // Since this must be a macro, mark the macro enabled now that it is no longer 961 // being expanded. 962 assert(Macro && "Token streams can't paste comments"); 963 Macro->EnableMacro(); 964 965 PP.HandleMicrosoftCommentPaste(Tok); 966 } 967 968 /// If \arg loc is a file ID and points inside the current macro 969 /// definition, returns the appropriate source location pointing at the 970 /// macro expansion source location entry, otherwise it returns an invalid 971 /// SourceLocation. 972 SourceLocation 973 TokenLexer::getExpansionLocForMacroDefLoc(SourceLocation loc) const { 974 assert(ExpandLocStart.isValid() && MacroExpansionStart.isValid() && 975 "Not appropriate for token streams"); 976 assert(loc.isValid() && loc.isFileID()); 977 978 SourceManager &SM = PP.getSourceManager(); 979 assert(SM.isInSLocAddrSpace(loc, MacroDefStart, MacroDefLength) && 980 "Expected loc to come from the macro definition"); 981 982 unsigned relativeOffset = 0; 983 SM.isInSLocAddrSpace(loc, MacroDefStart, MacroDefLength, &relativeOffset); 984 return MacroExpansionStart.getLocWithOffset(relativeOffset); 985 } 986 987 /// Finds the tokens that are consecutive (from the same FileID) 988 /// creates a single SLocEntry, and assigns SourceLocations to each token that 989 /// point to that SLocEntry. e.g for 990 /// assert(foo == bar); 991 /// There will be a single SLocEntry for the "foo == bar" chunk and locations 992 /// for the 'foo', '==', 'bar' tokens will point inside that chunk. 993 /// 994 /// \arg begin_tokens will be updated to a position past all the found 995 /// consecutive tokens. 996 static void updateConsecutiveMacroArgTokens(SourceManager &SM, 997 SourceLocation InstLoc, 998 Token *&begin_tokens, 999 Token * end_tokens) { 1000 assert(begin_tokens < end_tokens); 1001 1002 SourceLocation FirstLoc = begin_tokens->getLocation(); 1003 SourceLocation CurLoc = FirstLoc; 1004 1005 // Compare the source location offset of tokens and group together tokens that 1006 // are close, even if their locations point to different FileIDs. e.g. 1007 // 1008 // |bar | foo | cake | (3 tokens from 3 consecutive FileIDs) 1009 // ^ ^ 1010 // |bar foo cake| (one SLocEntry chunk for all tokens) 1011 // 1012 // we can perform this "merge" since the token's spelling location depends 1013 // on the relative offset. 1014 1015 Token *NextTok = begin_tokens + 1; 1016 for (; NextTok < end_tokens; ++NextTok) { 1017 SourceLocation NextLoc = NextTok->getLocation(); 1018 if (CurLoc.isFileID() != NextLoc.isFileID()) 1019 break; // Token from different kind of FileID. 1020 1021 int RelOffs; 1022 if (!SM.isInSameSLocAddrSpace(CurLoc, NextLoc, &RelOffs)) 1023 break; // Token from different local/loaded location. 1024 // Check that token is not before the previous token or more than 50 1025 // "characters" away. 1026 if (RelOffs < 0 || RelOffs > 50) 1027 break; 1028 1029 if (CurLoc.isMacroID() && !SM.isWrittenInSameFile(CurLoc, NextLoc)) 1030 break; // Token from a different macro. 1031 1032 CurLoc = NextLoc; 1033 } 1034 1035 // For the consecutive tokens, find the length of the SLocEntry to contain 1036 // all of them. 1037 Token &LastConsecutiveTok = *(NextTok-1); 1038 int LastRelOffs = 0; 1039 SM.isInSameSLocAddrSpace(FirstLoc, LastConsecutiveTok.getLocation(), 1040 &LastRelOffs); 1041 unsigned FullLength = LastRelOffs + LastConsecutiveTok.getLength(); 1042 1043 // Create a macro expansion SLocEntry that will "contain" all of the tokens. 1044 SourceLocation Expansion = 1045 SM.createMacroArgExpansionLoc(FirstLoc, InstLoc,FullLength); 1046 1047 // Change the location of the tokens from the spelling location to the new 1048 // expanded location. 1049 for (; begin_tokens < NextTok; ++begin_tokens) { 1050 Token &Tok = *begin_tokens; 1051 int RelOffs = 0; 1052 SM.isInSameSLocAddrSpace(FirstLoc, Tok.getLocation(), &RelOffs); 1053 Tok.setLocation(Expansion.getLocWithOffset(RelOffs)); 1054 } 1055 } 1056 1057 /// Creates SLocEntries and updates the locations of macro argument 1058 /// tokens to their new expanded locations. 1059 /// 1060 /// \param ArgIdSpellLoc the location of the macro argument id inside the macro 1061 /// definition. 1062 void TokenLexer::updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc, 1063 Token *begin_tokens, 1064 Token *end_tokens) { 1065 SourceManager &SM = PP.getSourceManager(); 1066 1067 SourceLocation InstLoc = 1068 getExpansionLocForMacroDefLoc(ArgIdSpellLoc); 1069 1070 while (begin_tokens < end_tokens) { 1071 // If there's only one token just create a SLocEntry for it. 1072 if (end_tokens - begin_tokens == 1) { 1073 Token &Tok = *begin_tokens; 1074 Tok.setLocation(SM.createMacroArgExpansionLoc(Tok.getLocation(), 1075 InstLoc, 1076 Tok.getLength())); 1077 return; 1078 } 1079 1080 updateConsecutiveMacroArgTokens(SM, InstLoc, begin_tokens, end_tokens); 1081 } 1082 } 1083 1084 void TokenLexer::PropagateLineStartLeadingSpaceInfo(Token &Result) { 1085 AtStartOfLine = Result.isAtStartOfLine(); 1086 HasLeadingSpace = Result.hasLeadingSpace(); 1087 } 1088