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