1 //===--- PPLexerChange.cpp - Handle changing lexers in the preprocessor ---===// 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 pieces of the Preprocessor interface that manage the 11 // current lexer stack. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/Lex/Preprocessor.h" 16 #include "clang/Basic/FileManager.h" 17 #include "clang/Basic/SourceManager.h" 18 #include "clang/Lex/HeaderSearch.h" 19 #include "clang/Lex/LexDiagnostic.h" 20 #include "clang/Lex/MacroInfo.h" 21 #include "llvm/ADT/StringSwitch.h" 22 #include "llvm/Support/FileSystem.h" 23 #include "llvm/Support/MemoryBuffer.h" 24 #include "llvm/Support/Path.h" 25 using namespace clang; 26 27 PPCallbacks::~PPCallbacks() {} 28 29 //===----------------------------------------------------------------------===// 30 // Miscellaneous Methods. 31 //===----------------------------------------------------------------------===// 32 33 /// isInPrimaryFile - Return true if we're in the top-level file, not in a 34 /// \#include. This looks through macro expansions and active _Pragma lexers. 35 bool Preprocessor::isInPrimaryFile() const { 36 if (IsFileLexer()) 37 return IncludeMacroStack.empty(); 38 39 // If there are any stacked lexers, we're in a #include. 40 assert(IsFileLexer(IncludeMacroStack[0]) && 41 "Top level include stack isn't our primary lexer?"); 42 for (unsigned i = 1, e = IncludeMacroStack.size(); i != e; ++i) 43 if (IsFileLexer(IncludeMacroStack[i])) 44 return false; 45 return true; 46 } 47 48 /// getCurrentLexer - Return the current file lexer being lexed from. Note 49 /// that this ignores any potentially active macro expansions and _Pragma 50 /// expansions going on at the time. 51 PreprocessorLexer *Preprocessor::getCurrentFileLexer() const { 52 if (IsFileLexer()) 53 return CurPPLexer; 54 55 // Look for a stacked lexer. 56 for (unsigned i = IncludeMacroStack.size(); i != 0; --i) { 57 const IncludeStackInfo& ISI = IncludeMacroStack[i-1]; 58 if (IsFileLexer(ISI)) 59 return ISI.ThePPLexer; 60 } 61 return nullptr; 62 } 63 64 65 //===----------------------------------------------------------------------===// 66 // Methods for Entering and Callbacks for leaving various contexts 67 //===----------------------------------------------------------------------===// 68 69 /// EnterSourceFile - Add a source file to the top of the include stack and 70 /// start lexing tokens from it instead of the current buffer. 71 bool Preprocessor::EnterSourceFile(FileID FID, const DirectoryLookup *CurDir, 72 SourceLocation Loc) { 73 assert(!CurTokenLexer && "Cannot #include a file inside a macro!"); 74 ++NumEnteredSourceFiles; 75 76 if (MaxIncludeStackDepth < IncludeMacroStack.size()) 77 MaxIncludeStackDepth = IncludeMacroStack.size(); 78 79 if (PTH) { 80 if (PTHLexer *PL = PTH->CreateLexer(FID)) { 81 EnterSourceFileWithPTH(PL, CurDir); 82 return false; 83 } 84 } 85 86 // Get the MemoryBuffer for this FID, if it fails, we fail. 87 bool Invalid = false; 88 const llvm::MemoryBuffer *InputFile = 89 getSourceManager().getBuffer(FID, Loc, &Invalid); 90 if (Invalid) { 91 SourceLocation FileStart = SourceMgr.getLocForStartOfFile(FID); 92 Diag(Loc, diag::err_pp_error_opening_file) 93 << std::string(SourceMgr.getBufferName(FileStart)) << ""; 94 return true; 95 } 96 97 if (isCodeCompletionEnabled() && 98 SourceMgr.getFileEntryForID(FID) == CodeCompletionFile) { 99 CodeCompletionFileLoc = SourceMgr.getLocForStartOfFile(FID); 100 CodeCompletionLoc = 101 CodeCompletionFileLoc.getLocWithOffset(CodeCompletionOffset); 102 } 103 104 EnterSourceFileWithLexer(new Lexer(FID, InputFile, *this), CurDir); 105 return false; 106 } 107 108 /// EnterSourceFileWithLexer - Add a source file to the top of the include stack 109 /// and start lexing tokens from it instead of the current buffer. 110 void Preprocessor::EnterSourceFileWithLexer(Lexer *TheLexer, 111 const DirectoryLookup *CurDir) { 112 113 // Add the current lexer to the include stack. 114 if (CurPPLexer || CurTokenLexer) 115 PushIncludeMacroStack(); 116 117 CurLexer.reset(TheLexer); 118 CurPPLexer = TheLexer; 119 CurDirLookup = CurDir; 120 CurSubmodule = nullptr; 121 if (CurLexerKind != CLK_LexAfterModuleImport) 122 CurLexerKind = CLK_Lexer; 123 124 // Notify the client, if desired, that we are in a new source file. 125 if (Callbacks && !CurLexer->Is_PragmaLexer) { 126 SrcMgr::CharacteristicKind FileType = 127 SourceMgr.getFileCharacteristic(CurLexer->getFileLoc()); 128 129 Callbacks->FileChanged(CurLexer->getFileLoc(), 130 PPCallbacks::EnterFile, FileType); 131 } 132 } 133 134 /// EnterSourceFileWithPTH - Add a source file to the top of the include stack 135 /// and start getting tokens from it using the PTH cache. 136 void Preprocessor::EnterSourceFileWithPTH(PTHLexer *PL, 137 const DirectoryLookup *CurDir) { 138 139 if (CurPPLexer || CurTokenLexer) 140 PushIncludeMacroStack(); 141 142 CurDirLookup = CurDir; 143 CurPTHLexer.reset(PL); 144 CurPPLexer = CurPTHLexer.get(); 145 CurSubmodule = nullptr; 146 if (CurLexerKind != CLK_LexAfterModuleImport) 147 CurLexerKind = CLK_PTHLexer; 148 149 // Notify the client, if desired, that we are in a new source file. 150 if (Callbacks) { 151 FileID FID = CurPPLexer->getFileID(); 152 SourceLocation EnterLoc = SourceMgr.getLocForStartOfFile(FID); 153 SrcMgr::CharacteristicKind FileType = 154 SourceMgr.getFileCharacteristic(EnterLoc); 155 Callbacks->FileChanged(EnterLoc, PPCallbacks::EnterFile, FileType); 156 } 157 } 158 159 /// EnterMacro - Add a Macro to the top of the include stack and start lexing 160 /// tokens from it instead of the current buffer. 161 void Preprocessor::EnterMacro(Token &Tok, SourceLocation ILEnd, 162 MacroInfo *Macro, MacroArgs *Args) { 163 std::unique_ptr<TokenLexer> TokLexer; 164 if (NumCachedTokenLexers == 0) { 165 TokLexer = llvm::make_unique<TokenLexer>(Tok, ILEnd, Macro, Args, *this); 166 } else { 167 TokLexer = std::move(TokenLexerCache[--NumCachedTokenLexers]); 168 TokLexer->Init(Tok, ILEnd, Macro, Args); 169 } 170 171 PushIncludeMacroStack(); 172 CurDirLookup = nullptr; 173 CurTokenLexer = std::move(TokLexer); 174 if (CurLexerKind != CLK_LexAfterModuleImport) 175 CurLexerKind = CLK_TokenLexer; 176 } 177 178 /// EnterTokenStream - Add a "macro" context to the top of the include stack, 179 /// which will cause the lexer to start returning the specified tokens. 180 /// 181 /// If DisableMacroExpansion is true, tokens lexed from the token stream will 182 /// not be subject to further macro expansion. Otherwise, these tokens will 183 /// be re-macro-expanded when/if expansion is enabled. 184 /// 185 /// If OwnsTokens is false, this method assumes that the specified stream of 186 /// tokens has a permanent owner somewhere, so they do not need to be copied. 187 /// If it is true, it assumes the array of tokens is allocated with new[] and 188 /// must be freed. 189 /// 190 void Preprocessor::EnterTokenStream(const Token *Toks, unsigned NumToks, 191 bool DisableMacroExpansion, 192 bool OwnsTokens) { 193 if (CurLexerKind == CLK_CachingLexer) { 194 if (CachedLexPos < CachedTokens.size()) { 195 // We're entering tokens into the middle of our cached token stream. We 196 // can't represent that, so just insert the tokens into the buffer. 197 CachedTokens.insert(CachedTokens.begin() + CachedLexPos, 198 Toks, Toks + NumToks); 199 if (OwnsTokens) 200 delete [] Toks; 201 return; 202 } 203 204 // New tokens are at the end of the cached token sequnece; insert the 205 // token stream underneath the caching lexer. 206 ExitCachingLexMode(); 207 EnterTokenStream(Toks, NumToks, DisableMacroExpansion, OwnsTokens); 208 EnterCachingLexMode(); 209 return; 210 } 211 212 // Create a macro expander to expand from the specified token stream. 213 std::unique_ptr<TokenLexer> TokLexer; 214 if (NumCachedTokenLexers == 0) { 215 TokLexer = llvm::make_unique<TokenLexer>( 216 Toks, NumToks, DisableMacroExpansion, OwnsTokens, *this); 217 } else { 218 TokLexer = std::move(TokenLexerCache[--NumCachedTokenLexers]); 219 TokLexer->Init(Toks, NumToks, DisableMacroExpansion, OwnsTokens); 220 } 221 222 // Save our current state. 223 PushIncludeMacroStack(); 224 CurDirLookup = nullptr; 225 CurTokenLexer = std::move(TokLexer); 226 if (CurLexerKind != CLK_LexAfterModuleImport) 227 CurLexerKind = CLK_TokenLexer; 228 } 229 230 /// \brief Compute the relative path that names the given file relative to 231 /// the given directory. 232 static void computeRelativePath(FileManager &FM, const DirectoryEntry *Dir, 233 const FileEntry *File, 234 SmallString<128> &Result) { 235 Result.clear(); 236 237 StringRef FilePath = File->getDir()->getName(); 238 StringRef Path = FilePath; 239 while (!Path.empty()) { 240 if (const DirectoryEntry *CurDir = FM.getDirectory(Path)) { 241 if (CurDir == Dir) { 242 Result = FilePath.substr(Path.size()); 243 llvm::sys::path::append(Result, 244 llvm::sys::path::filename(File->getName())); 245 return; 246 } 247 } 248 249 Path = llvm::sys::path::parent_path(Path); 250 } 251 252 Result = File->getName(); 253 } 254 255 void Preprocessor::PropagateLineStartLeadingSpaceInfo(Token &Result) { 256 if (CurTokenLexer) { 257 CurTokenLexer->PropagateLineStartLeadingSpaceInfo(Result); 258 return; 259 } 260 if (CurLexer) { 261 CurLexer->PropagateLineStartLeadingSpaceInfo(Result); 262 return; 263 } 264 // FIXME: Handle other kinds of lexers? It generally shouldn't matter, 265 // but it might if they're empty? 266 } 267 268 /// \brief Determine the location to use as the end of the buffer for a lexer. 269 /// 270 /// If the file ends with a newline, form the EOF token on the newline itself, 271 /// rather than "on the line following it", which doesn't exist. This makes 272 /// diagnostics relating to the end of file include the last file that the user 273 /// actually typed, which is goodness. 274 const char *Preprocessor::getCurLexerEndPos() { 275 const char *EndPos = CurLexer->BufferEnd; 276 if (EndPos != CurLexer->BufferStart && 277 (EndPos[-1] == '\n' || EndPos[-1] == '\r')) { 278 --EndPos; 279 280 // Handle \n\r and \r\n: 281 if (EndPos != CurLexer->BufferStart && 282 (EndPos[-1] == '\n' || EndPos[-1] == '\r') && 283 EndPos[-1] != EndPos[0]) 284 --EndPos; 285 } 286 287 return EndPos; 288 } 289 290 291 /// HandleEndOfFile - This callback is invoked when the lexer hits the end of 292 /// the current file. This either returns the EOF token or pops a level off 293 /// the include stack and keeps going. 294 bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) { 295 assert(!CurTokenLexer && 296 "Ending a file when currently in a macro!"); 297 298 // See if this file had a controlling macro. 299 if (CurPPLexer) { // Not ending a macro, ignore it. 300 if (const IdentifierInfo *ControllingMacro = 301 CurPPLexer->MIOpt.GetControllingMacroAtEndOfFile()) { 302 // Okay, this has a controlling macro, remember in HeaderFileInfo. 303 if (const FileEntry *FE = 304 SourceMgr.getFileEntryForID(CurPPLexer->getFileID())) { 305 HeaderInfo.SetFileControllingMacro(FE, ControllingMacro); 306 if (MacroInfo *MI = 307 getMacroInfo(const_cast<IdentifierInfo*>(ControllingMacro))) { 308 MI->UsedForHeaderGuard = true; 309 } 310 if (const IdentifierInfo *DefinedMacro = 311 CurPPLexer->MIOpt.GetDefinedMacro()) { 312 if (!ControllingMacro->hasMacroDefinition() && 313 DefinedMacro != ControllingMacro && 314 HeaderInfo.FirstTimeLexingFile(FE)) { 315 316 // If the edit distance between the two macros is more than 50%, 317 // DefinedMacro may not be header guard, or can be header guard of 318 // another header file. Therefore, it maybe defining something 319 // completely different. This can be observed in the wild when 320 // handling feature macros or header guards in different files. 321 322 const StringRef ControllingMacroName = ControllingMacro->getName(); 323 const StringRef DefinedMacroName = DefinedMacro->getName(); 324 const size_t MaxHalfLength = std::max(ControllingMacroName.size(), 325 DefinedMacroName.size()) / 2; 326 const unsigned ED = ControllingMacroName.edit_distance( 327 DefinedMacroName, true, MaxHalfLength); 328 if (ED <= MaxHalfLength) { 329 // Emit a warning for a bad header guard. 330 Diag(CurPPLexer->MIOpt.GetMacroLocation(), 331 diag::warn_header_guard) 332 << CurPPLexer->MIOpt.GetMacroLocation() << ControllingMacro; 333 Diag(CurPPLexer->MIOpt.GetDefinedLocation(), 334 diag::note_header_guard) 335 << CurPPLexer->MIOpt.GetDefinedLocation() << DefinedMacro 336 << ControllingMacro 337 << FixItHint::CreateReplacement( 338 CurPPLexer->MIOpt.GetDefinedLocation(), 339 ControllingMacro->getName()); 340 } 341 } 342 } 343 } 344 } 345 } 346 347 // Complain about reaching a true EOF within arc_cf_code_audited. 348 // We don't want to complain about reaching the end of a macro 349 // instantiation or a _Pragma. 350 if (PragmaARCCFCodeAuditedLoc.isValid() && 351 !isEndOfMacro && !(CurLexer && CurLexer->Is_PragmaLexer)) { 352 Diag(PragmaARCCFCodeAuditedLoc, diag::err_pp_eof_in_arc_cf_code_audited); 353 354 // Recover by leaving immediately. 355 PragmaARCCFCodeAuditedLoc = SourceLocation(); 356 } 357 358 // If this is a #include'd file, pop it off the include stack and continue 359 // lexing the #includer file. 360 if (!IncludeMacroStack.empty()) { 361 362 // If we lexed the code-completion file, act as if we reached EOF. 363 if (isCodeCompletionEnabled() && CurPPLexer && 364 SourceMgr.getLocForStartOfFile(CurPPLexer->getFileID()) == 365 CodeCompletionFileLoc) { 366 if (CurLexer) { 367 Result.startToken(); 368 CurLexer->FormTokenWithChars(Result, CurLexer->BufferEnd, tok::eof); 369 CurLexer.reset(); 370 } else { 371 assert(CurPTHLexer && "Got EOF but no current lexer set!"); 372 CurPTHLexer->getEOF(Result); 373 CurPTHLexer.reset(); 374 } 375 376 CurPPLexer = nullptr; 377 return true; 378 } 379 380 if (!isEndOfMacro && CurPPLexer && 381 SourceMgr.getIncludeLoc(CurPPLexer->getFileID()).isValid()) { 382 // Notify SourceManager to record the number of FileIDs that were created 383 // during lexing of the #include'd file. 384 unsigned NumFIDs = 385 SourceMgr.local_sloc_entry_size() - 386 CurPPLexer->getInitialNumSLocEntries() + 1/*#include'd file*/; 387 SourceMgr.setNumCreatedFIDsForFileID(CurPPLexer->getFileID(), NumFIDs); 388 } 389 390 FileID ExitedFID; 391 if (Callbacks && !isEndOfMacro && CurPPLexer) 392 ExitedFID = CurPPLexer->getFileID(); 393 394 bool LeavingSubmodule = CurSubmodule && CurLexer; 395 if (LeavingSubmodule) { 396 // Notify the parser that we've left the module. 397 const char *EndPos = getCurLexerEndPos(); 398 Result.startToken(); 399 CurLexer->BufferPtr = EndPos; 400 CurLexer->FormTokenWithChars(Result, EndPos, tok::annot_module_end); 401 Result.setAnnotationEndLoc(Result.getLocation()); 402 Result.setAnnotationValue(CurSubmodule); 403 } 404 405 // We're done with the #included file. 406 RemoveTopOfLexerStack(); 407 408 // Propagate info about start-of-line/leading white-space/etc. 409 PropagateLineStartLeadingSpaceInfo(Result); 410 411 // Notify the client, if desired, that we are in a new source file. 412 if (Callbacks && !isEndOfMacro && CurPPLexer) { 413 SrcMgr::CharacteristicKind FileType = 414 SourceMgr.getFileCharacteristic(CurPPLexer->getSourceLocation()); 415 Callbacks->FileChanged(CurPPLexer->getSourceLocation(), 416 PPCallbacks::ExitFile, FileType, ExitedFID); 417 } 418 419 // Client should lex another token unless we generated an EOM. 420 return LeavingSubmodule; 421 } 422 423 // If this is the end of the main file, form an EOF token. 424 if (CurLexer) { 425 const char *EndPos = getCurLexerEndPos(); 426 Result.startToken(); 427 CurLexer->BufferPtr = EndPos; 428 CurLexer->FormTokenWithChars(Result, EndPos, tok::eof); 429 430 if (isCodeCompletionEnabled()) { 431 // Inserting the code-completion point increases the source buffer by 1, 432 // but the main FileID was created before inserting the point. 433 // Compensate by reducing the EOF location by 1, otherwise the location 434 // will point to the next FileID. 435 // FIXME: This is hacky, the code-completion point should probably be 436 // inserted before the main FileID is created. 437 if (CurLexer->getFileLoc() == CodeCompletionFileLoc) 438 Result.setLocation(Result.getLocation().getLocWithOffset(-1)); 439 } 440 441 if (!isIncrementalProcessingEnabled()) 442 // We're done with lexing. 443 CurLexer.reset(); 444 } else { 445 assert(CurPTHLexer && "Got EOF but no current lexer set!"); 446 CurPTHLexer->getEOF(Result); 447 CurPTHLexer.reset(); 448 } 449 450 if (!isIncrementalProcessingEnabled()) 451 CurPPLexer = nullptr; 452 453 if (TUKind == TU_Complete) { 454 // This is the end of the top-level file. 'WarnUnusedMacroLocs' has 455 // collected all macro locations that we need to warn because they are not 456 // used. 457 for (WarnUnusedMacroLocsTy::iterator 458 I=WarnUnusedMacroLocs.begin(), E=WarnUnusedMacroLocs.end(); 459 I!=E; ++I) 460 Diag(*I, diag::pp_macro_not_used); 461 } 462 463 // If we are building a module that has an umbrella header, make sure that 464 // each of the headers within the directory covered by the umbrella header 465 // was actually included by the umbrella header. 466 if (Module *Mod = getCurrentModule()) { 467 if (Mod->getUmbrellaHeader()) { 468 SourceLocation StartLoc 469 = SourceMgr.getLocForStartOfFile(SourceMgr.getMainFileID()); 470 471 if (!getDiagnostics().isIgnored(diag::warn_uncovered_module_header, 472 StartLoc)) { 473 ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap(); 474 const DirectoryEntry *Dir = Mod->getUmbrellaDir(); 475 vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem(); 476 std::error_code EC; 477 for (vfs::recursive_directory_iterator Entry(FS, Dir->getName(), EC), End; 478 Entry != End && !EC; Entry.increment(EC)) { 479 using llvm::StringSwitch; 480 481 // Check whether this entry has an extension typically associated with 482 // headers. 483 if (!StringSwitch<bool>(llvm::sys::path::extension(Entry->getName())) 484 .Cases(".h", ".H", ".hh", ".hpp", true) 485 .Default(false)) 486 continue; 487 488 if (const FileEntry *Header = 489 getFileManager().getFile(Entry->getName())) 490 if (!getSourceManager().hasFileInfo(Header)) { 491 if (!ModMap.isHeaderInUnavailableModule(Header)) { 492 // Find the relative path that would access this header. 493 SmallString<128> RelativePath; 494 computeRelativePath(FileMgr, Dir, Header, RelativePath); 495 Diag(StartLoc, diag::warn_uncovered_module_header) 496 << Mod->getFullModuleName() << RelativePath; 497 } 498 } 499 } 500 } 501 } 502 } 503 504 return true; 505 } 506 507 /// HandleEndOfTokenLexer - This callback is invoked when the current TokenLexer 508 /// hits the end of its token stream. 509 bool Preprocessor::HandleEndOfTokenLexer(Token &Result) { 510 assert(CurTokenLexer && !CurPPLexer && 511 "Ending a macro when currently in a #include file!"); 512 513 if (!MacroExpandingLexersStack.empty() && 514 MacroExpandingLexersStack.back().first == CurTokenLexer.get()) 515 removeCachedMacroExpandedTokensOfLastLexer(); 516 517 // Delete or cache the now-dead macro expander. 518 if (NumCachedTokenLexers == TokenLexerCacheSize) 519 CurTokenLexer.reset(); 520 else 521 TokenLexerCache[NumCachedTokenLexers++] = std::move(CurTokenLexer); 522 523 // Handle this like a #include file being popped off the stack. 524 return HandleEndOfFile(Result, true); 525 } 526 527 /// RemoveTopOfLexerStack - Pop the current lexer/macro exp off the top of the 528 /// lexer stack. This should only be used in situations where the current 529 /// state of the top-of-stack lexer is unknown. 530 void Preprocessor::RemoveTopOfLexerStack() { 531 assert(!IncludeMacroStack.empty() && "Ran out of stack entries to load"); 532 533 if (CurTokenLexer) { 534 // Delete or cache the now-dead macro expander. 535 if (NumCachedTokenLexers == TokenLexerCacheSize) 536 CurTokenLexer.reset(); 537 else 538 TokenLexerCache[NumCachedTokenLexers++] = std::move(CurTokenLexer); 539 } 540 541 PopIncludeMacroStack(); 542 } 543 544 /// HandleMicrosoftCommentPaste - When the macro expander pastes together a 545 /// comment (/##/) in microsoft mode, this method handles updating the current 546 /// state, returning the token on the next source line. 547 void Preprocessor::HandleMicrosoftCommentPaste(Token &Tok) { 548 assert(CurTokenLexer && !CurPPLexer && 549 "Pasted comment can only be formed from macro"); 550 551 // We handle this by scanning for the closest real lexer, switching it to 552 // raw mode and preprocessor mode. This will cause it to return \n as an 553 // explicit EOD token. 554 PreprocessorLexer *FoundLexer = nullptr; 555 bool LexerWasInPPMode = false; 556 for (unsigned i = 0, e = IncludeMacroStack.size(); i != e; ++i) { 557 IncludeStackInfo &ISI = *(IncludeMacroStack.end()-i-1); 558 if (ISI.ThePPLexer == nullptr) continue; // Scan for a real lexer. 559 560 // Once we find a real lexer, mark it as raw mode (disabling macro 561 // expansions) and preprocessor mode (return EOD). We know that the lexer 562 // was *not* in raw mode before, because the macro that the comment came 563 // from was expanded. However, it could have already been in preprocessor 564 // mode (#if COMMENT) in which case we have to return it to that mode and 565 // return EOD. 566 FoundLexer = ISI.ThePPLexer; 567 FoundLexer->LexingRawMode = true; 568 LexerWasInPPMode = FoundLexer->ParsingPreprocessorDirective; 569 FoundLexer->ParsingPreprocessorDirective = true; 570 break; 571 } 572 573 // Okay, we either found and switched over the lexer, or we didn't find a 574 // lexer. In either case, finish off the macro the comment came from, getting 575 // the next token. 576 if (!HandleEndOfTokenLexer(Tok)) Lex(Tok); 577 578 // Discarding comments as long as we don't have EOF or EOD. This 'comments 579 // out' the rest of the line, including any tokens that came from other macros 580 // that were active, as in: 581 // #define submacro a COMMENT b 582 // submacro c 583 // which should lex to 'a' only: 'b' and 'c' should be removed. 584 while (Tok.isNot(tok::eod) && Tok.isNot(tok::eof)) 585 Lex(Tok); 586 587 // If we got an eod token, then we successfully found the end of the line. 588 if (Tok.is(tok::eod)) { 589 assert(FoundLexer && "Can't get end of line without an active lexer"); 590 // Restore the lexer back to normal mode instead of raw mode. 591 FoundLexer->LexingRawMode = false; 592 593 // If the lexer was already in preprocessor mode, just return the EOD token 594 // to finish the preprocessor line. 595 if (LexerWasInPPMode) return; 596 597 // Otherwise, switch out of PP mode and return the next lexed token. 598 FoundLexer->ParsingPreprocessorDirective = false; 599 return Lex(Tok); 600 } 601 602 // If we got an EOF token, then we reached the end of the token stream but 603 // didn't find an explicit \n. This can only happen if there was no lexer 604 // active (an active lexer would return EOD at EOF if there was no \n in 605 // preprocessor directive mode), so just return EOF as our token. 606 assert(!FoundLexer && "Lexer should return EOD before EOF in PP mode"); 607 } 608