//===--- PPLexerChange.cpp - Handle changing lexers in the preprocessor ---===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements pieces of the Preprocessor interface that manage the // current lexer stack. // //===----------------------------------------------------------------------===// #include "clang/Lex/Preprocessor.h" #include "clang/Lex/HeaderSearch.h" #include "clang/Lex/MacroInfo.h" #include "clang/Basic/Diagnostic.h" #include "clang/Basic/SourceManager.h" using namespace clang; PPCallbacks::~PPCallbacks() { } //===----------------------------------------------------------------------===// // Miscellaneous Methods. //===----------------------------------------------------------------------===// /// isInPrimaryFile - Return true if we're in the top-level file, not in a /// #include. This looks through macro expansions and active _Pragma lexers. bool Preprocessor::isInPrimaryFile() const { if (CurLexer && !CurLexer->Is_PragmaLexer) return IncludeMacroStack.empty(); // If there are any stacked lexers, we're in a #include. assert(IncludeMacroStack[0].TheLexer && !IncludeMacroStack[0].TheLexer->Is_PragmaLexer && "Top level include stack isn't our primary lexer?"); for (unsigned i = 1, e = IncludeMacroStack.size(); i != e; ++i) if (IncludeMacroStack[i].TheLexer && !IncludeMacroStack[i].TheLexer->Is_PragmaLexer) return false; return true; } /// getCurrentLexer - Return the current file lexer being lexed from. Note /// that this ignores any potentially active macro expansions and _Pragma /// expansions going on at the time. Lexer *Preprocessor::getCurrentFileLexer() const { if (CurLexer && !CurLexer->Is_PragmaLexer) return CurLexer; // Look for a stacked lexer. for (unsigned i = IncludeMacroStack.size(); i != 0; --i) { Lexer *L = IncludeMacroStack[i-1].TheLexer; if (L && !L->Is_PragmaLexer) // Ignore macro & _Pragma expansions. return L; } return 0; } //===----------------------------------------------------------------------===// // Methods for Entering and Callbacks for leaving various contexts //===----------------------------------------------------------------------===// /// EnterSourceFile - Add a source file to the top of the include stack and /// start lexing tokens from it instead of the current buffer. Return true /// on failure. void Preprocessor::EnterSourceFile(unsigned FileID, const DirectoryLookup *CurDir) { assert(CurTokenLexer == 0 && "Cannot #include a file inside a macro!"); ++NumEnteredSourceFiles; if (MaxIncludeStackDepth < IncludeMacroStack.size()) MaxIncludeStackDepth = IncludeMacroStack.size(); Lexer *TheLexer = new Lexer(SourceLocation::getFileLoc(FileID, 0), *this); EnterSourceFileWithLexer(TheLexer, CurDir); } /// EnterSourceFile - Add a source file to the top of the include stack and /// start lexing tokens from it instead of the current buffer. void Preprocessor::EnterSourceFileWithLexer(Lexer *TheLexer, const DirectoryLookup *CurDir) { // Add the current lexer to the include stack. if (CurLexer || CurTokenLexer) IncludeMacroStack.push_back(IncludeStackInfo(CurLexer, CurDirLookup, CurTokenLexer)); CurLexer = TheLexer; CurDirLookup = CurDir; CurTokenLexer = 0; // Notify the client, if desired, that we are in a new source file. if (Callbacks && !CurLexer->Is_PragmaLexer) { SrcMgr::Characteristic_t FileType = SourceMgr.getFileCharacteristic(CurLexer->getFileLoc()); Callbacks->FileChanged(CurLexer->getFileLoc(), PPCallbacks::EnterFile, FileType); } } /// EnterMacro - Add a Macro to the top of the include stack and start lexing /// tokens from it instead of the current buffer. void Preprocessor::EnterMacro(Token &Tok, MacroArgs *Args) { IncludeMacroStack.push_back(IncludeStackInfo(CurLexer, CurDirLookup, CurTokenLexer)); CurLexer = 0; CurDirLookup = 0; if (NumCachedTokenLexers == 0) { CurTokenLexer = new TokenLexer(Tok, Args, *this); } else { CurTokenLexer = TokenLexerCache[--NumCachedTokenLexers]; CurTokenLexer->Init(Tok, Args); } } /// EnterTokenStream - Add a "macro" context to the top of the include stack, /// which will cause the lexer to start returning the specified tokens. /// /// If DisableMacroExpansion is true, tokens lexed from the token stream will /// not be subject to further macro expansion. Otherwise, these tokens will /// be re-macro-expanded when/if expansion is enabled. /// /// If OwnsTokens is false, this method assumes that the specified stream of /// tokens has a permanent owner somewhere, so they do not need to be copied. /// If it is true, it assumes the array of tokens is allocated with new[] and /// must be freed. /// void Preprocessor::EnterTokenStream(const Token *Toks, unsigned NumToks, bool DisableMacroExpansion, bool OwnsTokens) { // Save our current state. IncludeMacroStack.push_back(IncludeStackInfo(CurLexer, CurDirLookup, CurTokenLexer)); CurLexer = 0; CurDirLookup = 0; // Create a macro expander to expand from the specified token stream. if (NumCachedTokenLexers == 0) { CurTokenLexer = new TokenLexer(Toks, NumToks, DisableMacroExpansion, OwnsTokens, *this); } else { CurTokenLexer = TokenLexerCache[--NumCachedTokenLexers]; CurTokenLexer->Init(Toks, NumToks, DisableMacroExpansion, OwnsTokens); } } /// HandleEndOfFile - This callback is invoked when the lexer hits the end of /// the current file. This either returns the EOF token or pops a level off /// the include stack and keeps going. bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) { assert(!CurTokenLexer && "Ending a file when currently in a macro!"); // See if this file had a controlling macro. if (CurLexer) { // Not ending a macro, ignore it. if (const IdentifierInfo *ControllingMacro = CurLexer->MIOpt.GetControllingMacroAtEndOfFile()) { // Okay, this has a controlling macro, remember in PerFileInfo. if (const FileEntry *FE = SourceMgr.getFileEntryForLoc(CurLexer->getFileLoc())) HeaderInfo.SetFileControllingMacro(FE, ControllingMacro); } } // If this is a #include'd file, pop it off the include stack and continue // lexing the #includer file. if (!IncludeMacroStack.empty()) { // We're done with the #included file. RemoveTopOfLexerStack(); // Notify the client, if desired, that we are in a new source file. if (Callbacks && !isEndOfMacro && CurLexer) { SrcMgr::Characteristic_t FileType = SourceMgr.getFileCharacteristic(CurLexer->getFileLoc()); Callbacks->FileChanged(CurLexer->getSourceLocation(CurLexer->BufferPtr), PPCallbacks::ExitFile, FileType); } // Client should lex another token. return false; } // If the file ends with a newline, form the EOF token on the newline itself, // rather than "on the line following it", which doesn't exist. This makes // diagnostics relating to the end of file include the last file that the user // actually typed, which is goodness. const char *EndPos = CurLexer->BufferEnd; if (EndPos != CurLexer->BufferStart && (EndPos[-1] == '\n' || EndPos[-1] == '\r')) { --EndPos; // Handle \n\r and \r\n: if (EndPos != CurLexer->BufferStart && (EndPos[-1] == '\n' || EndPos[-1] == '\r') && EndPos[-1] != EndPos[0]) --EndPos; } Result.startToken(); CurLexer->BufferPtr = EndPos; CurLexer->FormTokenWithChars(Result, EndPos); Result.setKind(tok::eof); // We're done with the #included file. delete CurLexer; CurLexer = 0; // This is the end of the top-level file. If the diag::pp_macro_not_used // diagnostic is enabled, look for macros that have not been used. if (Diags.getDiagnosticLevel(diag::pp_macro_not_used) != Diagnostic::Ignored){ for (llvm::DenseMap::iterator I = Macros.begin(), E = Macros.end(); I != E; ++I) { if (!I->second->isUsed()) Diag(I->second->getDefinitionLoc(), diag::pp_macro_not_used); } } return true; } /// HandleEndOfTokenLexer - This callback is invoked when the current TokenLexer /// hits the end of its token stream. bool Preprocessor::HandleEndOfTokenLexer(Token &Result) { assert(CurTokenLexer && !CurLexer && "Ending a macro when currently in a #include file!"); // Delete or cache the now-dead macro expander. if (NumCachedTokenLexers == TokenLexerCacheSize) delete CurTokenLexer; else TokenLexerCache[NumCachedTokenLexers++] = CurTokenLexer; // Handle this like a #include file being popped off the stack. CurTokenLexer = 0; return HandleEndOfFile(Result, true); } /// RemoveTopOfLexerStack - Pop the current lexer/macro exp off the top of the /// lexer stack. This should only be used in situations where the current /// state of the top-of-stack lexer is unknown. void Preprocessor::RemoveTopOfLexerStack() { assert(!IncludeMacroStack.empty() && "Ran out of stack entries to load"); if (CurTokenLexer) { // Delete or cache the now-dead macro expander. if (NumCachedTokenLexers == TokenLexerCacheSize) delete CurTokenLexer; else TokenLexerCache[NumCachedTokenLexers++] = CurTokenLexer; } else { delete CurLexer; } CurLexer = IncludeMacroStack.back().TheLexer; CurDirLookup = IncludeMacroStack.back().TheDirLookup; CurTokenLexer = IncludeMacroStack.back().TheTokenLexer; IncludeMacroStack.pop_back(); } /// HandleMicrosoftCommentPaste - When the macro expander pastes together a /// comment (/##/) in microsoft mode, this method handles updating the current /// state, returning the token on the next source line. void Preprocessor::HandleMicrosoftCommentPaste(Token &Tok) { assert(CurTokenLexer && !CurLexer && "Pasted comment can only be formed from macro"); // We handle this by scanning for the closest real lexer, switching it to // raw mode and preprocessor mode. This will cause it to return \n as an // explicit EOM token. Lexer *FoundLexer = 0; bool LexerWasInPPMode = false; for (unsigned i = 0, e = IncludeMacroStack.size(); i != e; ++i) { IncludeStackInfo &ISI = *(IncludeMacroStack.end()-i-1); if (ISI.TheLexer == 0) continue; // Scan for a real lexer. // Once we find a real lexer, mark it as raw mode (disabling macro // expansions) and preprocessor mode (return EOM). We know that the lexer // was *not* in raw mode before, because the macro that the comment came // from was expanded. However, it could have already been in preprocessor // mode (#if COMMENT) in which case we have to return it to that mode and // return EOM. FoundLexer = ISI.TheLexer; FoundLexer->LexingRawMode = true; LexerWasInPPMode = FoundLexer->ParsingPreprocessorDirective; FoundLexer->ParsingPreprocessorDirective = true; break; } // Okay, we either found and switched over the lexer, or we didn't find a // lexer. In either case, finish off the macro the comment came from, getting // the next token. if (!HandleEndOfTokenLexer(Tok)) Lex(Tok); // Discarding comments as long as we don't have EOF or EOM. This 'comments // out' the rest of the line, including any tokens that came from other macros // that were active, as in: // #define submacro a COMMENT b // submacro c // which should lex to 'a' only: 'b' and 'c' should be removed. while (Tok.isNot(tok::eom) && Tok.isNot(tok::eof)) Lex(Tok); // If we got an eom token, then we successfully found the end of the line. if (Tok.is(tok::eom)) { assert(FoundLexer && "Can't get end of line without an active lexer"); // Restore the lexer back to normal mode instead of raw mode. FoundLexer->LexingRawMode = false; // If the lexer was already in preprocessor mode, just return the EOM token // to finish the preprocessor line. if (LexerWasInPPMode) return; // Otherwise, switch out of PP mode and return the next lexed token. FoundLexer->ParsingPreprocessorDirective = false; return Lex(Tok); } // If we got an EOF token, then we reached the end of the token stream but // didn't find an explicit \n. This can only happen if there was no lexer // active (an active lexer would return EOM at EOF if there was no \n in // preprocessor directive mode), so just return EOF as our token. assert(!FoundLexer && "Lexer should return EOM before EOF in PP mode"); }