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//===--- 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/Lex/LexDiagnostic.h"
#include "clang/Basic/SourceManager.h"
#include "llvm/Support/MemoryBuffer.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 (IsFileLexer())
return IncludeMacroStack.empty();
// If there are any stacked lexers, we're in a #include.
assert(IsFileLexer(IncludeMacroStack[0]) &&
"Top level include stack isn't our primary lexer?");
for (unsigned i = 1, e = IncludeMacroStack.size(); i != e; ++i)
if (IsFileLexer(IncludeMacroStack[i]))
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.
PreprocessorLexer *Preprocessor::getCurrentFileLexer() const {
if (IsFileLexer())
return CurPPLexer;
// Look for a stacked lexer.
for (unsigned i = IncludeMacroStack.size(); i != 0; --i) {
const IncludeStackInfo& ISI = IncludeMacroStack[i-1];
if (IsFileLexer(ISI))
return ISI.ThePPLexer;
}
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(FileID FID, const DirectoryLookup *CurDir) {
assert(CurTokenLexer == 0 && "Cannot #include a file inside a macro!");
++NumEnteredSourceFiles;
if (MaxIncludeStackDepth < IncludeMacroStack.size())
MaxIncludeStackDepth = IncludeMacroStack.size();
if (PTH) {
if (PTHLexer *PL = PTH->CreateLexer(FID))
return EnterSourceFileWithPTH(PL, CurDir);
}
EnterSourceFileWithLexer(new Lexer(FID, *this), CurDir);
}
/// EnterSourceFileWithLexer - 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 (CurPPLexer || CurTokenLexer)
PushIncludeMacroStack();
CurLexer.reset(TheLexer);
CurPPLexer = TheLexer;
CurDirLookup = CurDir;
// Notify the client, if desired, that we are in a new source file.
if (Callbacks && !CurLexer->Is_PragmaLexer) {
SrcMgr::CharacteristicKind FileType =
SourceMgr.getFileCharacteristic(CurLexer->getFileLoc());
Callbacks->FileChanged(CurLexer->getFileLoc(),
PPCallbacks::EnterFile, FileType);
}
}
/// EnterSourceFileWithPTH - Add a source file to the top of the include stack
/// and start getting tokens from it using the PTH cache.
void Preprocessor::EnterSourceFileWithPTH(PTHLexer *PL,
const DirectoryLookup *CurDir) {
if (CurPPLexer || CurTokenLexer)
PushIncludeMacroStack();
CurDirLookup = CurDir;
CurPTHLexer.reset(PL);
CurPPLexer = CurPTHLexer.get();
// Notify the client, if desired, that we are in a new source file.
if (Callbacks) {
FileID FID = CurPPLexer->getFileID();
SourceLocation EnterLoc = SourceMgr.getLocForStartOfFile(FID);
SrcMgr::CharacteristicKind FileType =
SourceMgr.getFileCharacteristic(EnterLoc);
Callbacks->FileChanged(EnterLoc, 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, SourceLocation ILEnd,
MacroArgs *Args) {
PushIncludeMacroStack();
CurDirLookup = 0;
if (NumCachedTokenLexers == 0) {
CurTokenLexer.reset(new TokenLexer(Tok, ILEnd, Args, *this));
} else {
CurTokenLexer.reset(TokenLexerCache[--NumCachedTokenLexers]);
CurTokenLexer->Init(Tok, ILEnd, 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.
PushIncludeMacroStack();
CurDirLookup = 0;
// Create a macro expander to expand from the specified token stream.
if (NumCachedTokenLexers == 0) {
CurTokenLexer.reset(new TokenLexer(Toks, NumToks, DisableMacroExpansion,
OwnsTokens, *this));
} else {
CurTokenLexer.reset(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 (CurPPLexer) { // Not ending a macro, ignore it.
if (const IdentifierInfo *ControllingMacro =
CurPPLexer->MIOpt.GetControllingMacroAtEndOfFile()) {
// Okay, this has a controlling macro, remember in PerFileInfo.
if (const FileEntry *FE =
SourceMgr.getFileEntryForID(CurPPLexer->getFileID()))
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 && CurPPLexer) {
SrcMgr::CharacteristicKind FileType =
SourceMgr.getFileCharacteristic(CurPPLexer->getSourceLocation());
Callbacks->FileChanged(CurPPLexer->getSourceLocation(),
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.
if (CurLexer) {
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, tok::eof);
// We're done with the #included file.
CurLexer.reset();
} else {
assert(CurPTHLexer && "Got EOF but no current lexer set!");
CurPTHLexer->getEOF(Result);
CurPTHLexer.reset();
}
CurPPLexer = 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 (getDiagnostics().getDiagnosticLevel(diag::pp_macro_not_used) !=
Diagnostic::Ignored) {
for (macro_iterator I = macro_begin(), E = macro_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 && !CurPPLexer &&
"Ending a macro when currently in a #include file!");
// Delete or cache the now-dead macro expander.
if (NumCachedTokenLexers == TokenLexerCacheSize)
CurTokenLexer.reset();
else
TokenLexerCache[NumCachedTokenLexers++] = CurTokenLexer.take();
// Handle this like a #include file being popped off the stack.
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)
CurTokenLexer.reset();
else
TokenLexerCache[NumCachedTokenLexers++] = CurTokenLexer.take();
}
PopIncludeMacroStack();
}
/// 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 && !CurPPLexer &&
"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.
PreprocessorLexer *FoundLexer = 0;
bool LexerWasInPPMode = false;
for (unsigned i = 0, e = IncludeMacroStack.size(); i != e; ++i) {
IncludeStackInfo &ISI = *(IncludeMacroStack.end()-i-1);
if (ISI.ThePPLexer == 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.ThePPLexer;
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");
}