PPLexerChange.cpp revision 207619
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/Lex/HeaderSearch.h" 17#include "clang/Lex/MacroInfo.h" 18#include "clang/Lex/LexDiagnostic.h" 19#include "clang/Basic/SourceManager.h" 20#include "llvm/Support/MemoryBuffer.h" 21using namespace clang; 22 23PPCallbacks::~PPCallbacks() {} 24 25//===----------------------------------------------------------------------===// 26// Miscellaneous Methods. 27//===----------------------------------------------------------------------===// 28 29/// isInPrimaryFile - Return true if we're in the top-level file, not in a 30/// #include. This looks through macro expansions and active _Pragma lexers. 31bool Preprocessor::isInPrimaryFile() const { 32 if (IsFileLexer()) 33 return IncludeMacroStack.empty(); 34 35 // If there are any stacked lexers, we're in a #include. 36 assert(IsFileLexer(IncludeMacroStack[0]) && 37 "Top level include stack isn't our primary lexer?"); 38 for (unsigned i = 1, e = IncludeMacroStack.size(); i != e; ++i) 39 if (IsFileLexer(IncludeMacroStack[i])) 40 return false; 41 return true; 42} 43 44/// getCurrentLexer - Return the current file lexer being lexed from. Note 45/// that this ignores any potentially active macro expansions and _Pragma 46/// expansions going on at the time. 47PreprocessorLexer *Preprocessor::getCurrentFileLexer() const { 48 if (IsFileLexer()) 49 return CurPPLexer; 50 51 // Look for a stacked lexer. 52 for (unsigned i = IncludeMacroStack.size(); i != 0; --i) { 53 const IncludeStackInfo& ISI = IncludeMacroStack[i-1]; 54 if (IsFileLexer(ISI)) 55 return ISI.ThePPLexer; 56 } 57 return 0; 58} 59 60 61//===----------------------------------------------------------------------===// 62// Methods for Entering and Callbacks for leaving various contexts 63//===----------------------------------------------------------------------===// 64 65/// EnterSourceFile - Add a source file to the top of the include stack and 66/// start lexing tokens from it instead of the current buffer. 67void Preprocessor::EnterSourceFile(FileID FID, const DirectoryLookup *CurDir, 68 SourceLocation Loc) { 69 assert(CurTokenLexer == 0 && "Cannot #include a file inside a macro!"); 70 ++NumEnteredSourceFiles; 71 72 if (MaxIncludeStackDepth < IncludeMacroStack.size()) 73 MaxIncludeStackDepth = IncludeMacroStack.size(); 74 75 if (PTH) { 76 if (PTHLexer *PL = PTH->CreateLexer(FID)) { 77 EnterSourceFileWithPTH(PL, CurDir); 78 return; 79 } 80 } 81 82 // Get the MemoryBuffer for this FID, if it fails, we fail. 83 bool Invalid = false; 84 const llvm::MemoryBuffer *InputFile = 85 getSourceManager().getBuffer(FID, Loc, &Invalid); 86 if (Invalid) { 87 SourceLocation FileStart = SourceMgr.getLocForStartOfFile(FID); 88 Diag(Loc, diag::err_pp_error_opening_file) 89 << std::string(SourceMgr.getBufferName(FileStart)) << ""; 90 return; 91 } 92 93 EnterSourceFileWithLexer(new Lexer(FID, InputFile, *this), CurDir); 94 return; 95} 96 97/// EnterSourceFileWithLexer - Add a source file to the top of the include stack 98/// and start lexing tokens from it instead of the current buffer. 99void Preprocessor::EnterSourceFileWithLexer(Lexer *TheLexer, 100 const DirectoryLookup *CurDir) { 101 102 // Add the current lexer to the include stack. 103 if (CurPPLexer || CurTokenLexer) 104 PushIncludeMacroStack(); 105 106 CurLexer.reset(TheLexer); 107 CurPPLexer = TheLexer; 108 CurDirLookup = CurDir; 109 110 // Notify the client, if desired, that we are in a new source file. 111 if (Callbacks && !CurLexer->Is_PragmaLexer) { 112 SrcMgr::CharacteristicKind FileType = 113 SourceMgr.getFileCharacteristic(CurLexer->getFileLoc()); 114 115 Callbacks->FileChanged(CurLexer->getFileLoc(), 116 PPCallbacks::EnterFile, FileType); 117 } 118} 119 120/// EnterSourceFileWithPTH - Add a source file to the top of the include stack 121/// and start getting tokens from it using the PTH cache. 122void Preprocessor::EnterSourceFileWithPTH(PTHLexer *PL, 123 const DirectoryLookup *CurDir) { 124 125 if (CurPPLexer || CurTokenLexer) 126 PushIncludeMacroStack(); 127 128 CurDirLookup = CurDir; 129 CurPTHLexer.reset(PL); 130 CurPPLexer = CurPTHLexer.get(); 131 132 // Notify the client, if desired, that we are in a new source file. 133 if (Callbacks) { 134 FileID FID = CurPPLexer->getFileID(); 135 SourceLocation EnterLoc = SourceMgr.getLocForStartOfFile(FID); 136 SrcMgr::CharacteristicKind FileType = 137 SourceMgr.getFileCharacteristic(EnterLoc); 138 Callbacks->FileChanged(EnterLoc, PPCallbacks::EnterFile, FileType); 139 } 140} 141 142/// EnterMacro - Add a Macro to the top of the include stack and start lexing 143/// tokens from it instead of the current buffer. 144void Preprocessor::EnterMacro(Token &Tok, SourceLocation ILEnd, 145 MacroArgs *Args) { 146 PushIncludeMacroStack(); 147 CurDirLookup = 0; 148 149 if (NumCachedTokenLexers == 0) { 150 CurTokenLexer.reset(new TokenLexer(Tok, ILEnd, Args, *this)); 151 } else { 152 CurTokenLexer.reset(TokenLexerCache[--NumCachedTokenLexers]); 153 CurTokenLexer->Init(Tok, ILEnd, Args); 154 } 155} 156 157/// EnterTokenStream - Add a "macro" context to the top of the include stack, 158/// which will cause the lexer to start returning the specified tokens. 159/// 160/// If DisableMacroExpansion is true, tokens lexed from the token stream will 161/// not be subject to further macro expansion. Otherwise, these tokens will 162/// be re-macro-expanded when/if expansion is enabled. 163/// 164/// If OwnsTokens is false, this method assumes that the specified stream of 165/// tokens has a permanent owner somewhere, so they do not need to be copied. 166/// If it is true, it assumes the array of tokens is allocated with new[] and 167/// must be freed. 168/// 169void Preprocessor::EnterTokenStream(const Token *Toks, unsigned NumToks, 170 bool DisableMacroExpansion, 171 bool OwnsTokens) { 172 // Save our current state. 173 PushIncludeMacroStack(); 174 CurDirLookup = 0; 175 176 // Create a macro expander to expand from the specified token stream. 177 if (NumCachedTokenLexers == 0) { 178 CurTokenLexer.reset(new TokenLexer(Toks, NumToks, DisableMacroExpansion, 179 OwnsTokens, *this)); 180 } else { 181 CurTokenLexer.reset(TokenLexerCache[--NumCachedTokenLexers]); 182 CurTokenLexer->Init(Toks, NumToks, DisableMacroExpansion, OwnsTokens); 183 } 184} 185 186/// HandleEndOfFile - This callback is invoked when the lexer hits the end of 187/// the current file. This either returns the EOF token or pops a level off 188/// the include stack and keeps going. 189bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) { 190 assert(!CurTokenLexer && 191 "Ending a file when currently in a macro!"); 192 193 // See if this file had a controlling macro. 194 if (CurPPLexer) { // Not ending a macro, ignore it. 195 if (const IdentifierInfo *ControllingMacro = 196 CurPPLexer->MIOpt.GetControllingMacroAtEndOfFile()) { 197 // Okay, this has a controlling macro, remember in HeaderFileInfo. 198 if (const FileEntry *FE = 199 SourceMgr.getFileEntryForID(CurPPLexer->getFileID())) 200 HeaderInfo.SetFileControllingMacro(FE, ControllingMacro); 201 } 202 } 203 204 // If this is a #include'd file, pop it off the include stack and continue 205 // lexing the #includer file. 206 if (!IncludeMacroStack.empty()) { 207 // We're done with the #included file. 208 RemoveTopOfLexerStack(); 209 210 // Notify the client, if desired, that we are in a new source file. 211 if (Callbacks && !isEndOfMacro && CurPPLexer) { 212 SrcMgr::CharacteristicKind FileType = 213 SourceMgr.getFileCharacteristic(CurPPLexer->getSourceLocation()); 214 Callbacks->FileChanged(CurPPLexer->getSourceLocation(), 215 PPCallbacks::ExitFile, FileType); 216 } 217 218 // Client should lex another token. 219 return false; 220 } 221 222 // If the file ends with a newline, form the EOF token on the newline itself, 223 // rather than "on the line following it", which doesn't exist. This makes 224 // diagnostics relating to the end of file include the last file that the user 225 // actually typed, which is goodness. 226 if (CurLexer) { 227 const char *EndPos = CurLexer->BufferEnd; 228 if (EndPos != CurLexer->BufferStart && 229 (EndPos[-1] == '\n' || EndPos[-1] == '\r')) { 230 --EndPos; 231 232 // Handle \n\r and \r\n: 233 if (EndPos != CurLexer->BufferStart && 234 (EndPos[-1] == '\n' || EndPos[-1] == '\r') && 235 EndPos[-1] != EndPos[0]) 236 --EndPos; 237 } 238 239 Result.startToken(); 240 CurLexer->BufferPtr = EndPos; 241 CurLexer->FormTokenWithChars(Result, EndPos, tok::eof); 242 243 // We're done with the #included file. 244 CurLexer.reset(); 245 } else { 246 assert(CurPTHLexer && "Got EOF but no current lexer set!"); 247 CurPTHLexer->getEOF(Result); 248 CurPTHLexer.reset(); 249 } 250 251 CurPPLexer = 0; 252 253 // This is the end of the top-level file. If the diag::pp_macro_not_used 254 // diagnostic is enabled, look for macros that have not been used. 255 if (getDiagnostics().getDiagnosticLevel(diag::pp_macro_not_used) != 256 Diagnostic::Ignored) { 257 for (macro_iterator I = macro_begin(false), E = macro_end(false); 258 I != E; ++I) 259 if (!I->second->isUsed()) 260 Diag(I->second->getDefinitionLoc(), diag::pp_macro_not_used); 261 } 262 263 return true; 264} 265 266/// HandleEndOfTokenLexer - This callback is invoked when the current TokenLexer 267/// hits the end of its token stream. 268bool Preprocessor::HandleEndOfTokenLexer(Token &Result) { 269 assert(CurTokenLexer && !CurPPLexer && 270 "Ending a macro when currently in a #include file!"); 271 272 // Delete or cache the now-dead macro expander. 273 if (NumCachedTokenLexers == TokenLexerCacheSize) 274 CurTokenLexer.reset(); 275 else 276 TokenLexerCache[NumCachedTokenLexers++] = CurTokenLexer.take(); 277 278 // Handle this like a #include file being popped off the stack. 279 return HandleEndOfFile(Result, true); 280} 281 282/// RemoveTopOfLexerStack - Pop the current lexer/macro exp off the top of the 283/// lexer stack. This should only be used in situations where the current 284/// state of the top-of-stack lexer is unknown. 285void Preprocessor::RemoveTopOfLexerStack() { 286 assert(!IncludeMacroStack.empty() && "Ran out of stack entries to load"); 287 288 if (CurTokenLexer) { 289 // Delete or cache the now-dead macro expander. 290 if (NumCachedTokenLexers == TokenLexerCacheSize) 291 CurTokenLexer.reset(); 292 else 293 TokenLexerCache[NumCachedTokenLexers++] = CurTokenLexer.take(); 294 } 295 296 PopIncludeMacroStack(); 297} 298 299/// HandleMicrosoftCommentPaste - When the macro expander pastes together a 300/// comment (/##/) in microsoft mode, this method handles updating the current 301/// state, returning the token on the next source line. 302void Preprocessor::HandleMicrosoftCommentPaste(Token &Tok) { 303 assert(CurTokenLexer && !CurPPLexer && 304 "Pasted comment can only be formed from macro"); 305 306 // We handle this by scanning for the closest real lexer, switching it to 307 // raw mode and preprocessor mode. This will cause it to return \n as an 308 // explicit EOM token. 309 PreprocessorLexer *FoundLexer = 0; 310 bool LexerWasInPPMode = false; 311 for (unsigned i = 0, e = IncludeMacroStack.size(); i != e; ++i) { 312 IncludeStackInfo &ISI = *(IncludeMacroStack.end()-i-1); 313 if (ISI.ThePPLexer == 0) continue; // Scan for a real lexer. 314 315 // Once we find a real lexer, mark it as raw mode (disabling macro 316 // expansions) and preprocessor mode (return EOM). We know that the lexer 317 // was *not* in raw mode before, because the macro that the comment came 318 // from was expanded. However, it could have already been in preprocessor 319 // mode (#if COMMENT) in which case we have to return it to that mode and 320 // return EOM. 321 FoundLexer = ISI.ThePPLexer; 322 FoundLexer->LexingRawMode = true; 323 LexerWasInPPMode = FoundLexer->ParsingPreprocessorDirective; 324 FoundLexer->ParsingPreprocessorDirective = true; 325 break; 326 } 327 328 // Okay, we either found and switched over the lexer, or we didn't find a 329 // lexer. In either case, finish off the macro the comment came from, getting 330 // the next token. 331 if (!HandleEndOfTokenLexer(Tok)) Lex(Tok); 332 333 // Discarding comments as long as we don't have EOF or EOM. This 'comments 334 // out' the rest of the line, including any tokens that came from other macros 335 // that were active, as in: 336 // #define submacro a COMMENT b 337 // submacro c 338 // which should lex to 'a' only: 'b' and 'c' should be removed. 339 while (Tok.isNot(tok::eom) && Tok.isNot(tok::eof)) 340 Lex(Tok); 341 342 // If we got an eom token, then we successfully found the end of the line. 343 if (Tok.is(tok::eom)) { 344 assert(FoundLexer && "Can't get end of line without an active lexer"); 345 // Restore the lexer back to normal mode instead of raw mode. 346 FoundLexer->LexingRawMode = false; 347 348 // If the lexer was already in preprocessor mode, just return the EOM token 349 // to finish the preprocessor line. 350 if (LexerWasInPPMode) return; 351 352 // Otherwise, switch out of PP mode and return the next lexed token. 353 FoundLexer->ParsingPreprocessorDirective = false; 354 return Lex(Tok); 355 } 356 357 // If we got an EOF token, then we reached the end of the token stream but 358 // didn't find an explicit \n. This can only happen if there was no lexer 359 // active (an active lexer would return EOM at EOF if there was no \n in 360 // preprocessor directive mode), so just return EOF as our token. 361 assert(!FoundLexer && "Lexer should return EOM before EOF in PP mode"); 362} 363