Implement support for the extremely atrocious MS /##/ extension,
which pastes together a comment. This is only enabled with
-fms-extensions of course.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@46845 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Lex/Preprocessor.cpp b/Lex/Preprocessor.cpp
index 40fd322..f4e7374 100644
--- a/Lex/Preprocessor.cpp
+++ b/Lex/Preprocessor.cpp
@@ -1358,6 +1358,71 @@
return HandleEndOfFile(Result, true);
}
+/// 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(CurMacroExpander && !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 (!HandleEndOfMacro(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");
+ return;
+}
//===----------------------------------------------------------------------===//
// Utility Methods for Preprocessor Directive Handling.