From 3ae09ee2ed3e345e33b8350149b09eb64d913e81 Mon Sep 17 00:00:00 2001 From: Nico Weber Date: Fri, 9 May 2014 18:09:42 +0000 Subject: [PATCH] Don't leak MacroArgs when using code completion, PR19688. MacroArgs are owned by TokenLexer, and when a TokenLexer is destroyed, it'll call its MacroArgs's destroy() method. destroy() only appends the MacroArg to Preprocessor's MacroArgCache list, and Preprocessor's destructor then calls deallocate() on all MacroArgs in that list. This method then ends up freeing the MacroArgs's memory. In a code completion context, Parser::cutOffParsing() gets called when a code completion token is hit, which changes the type of the current token to tok::eof. eof tokens aren't always ConsumeToken()ed, so Preprocessor::HandleEndOfFile() isn't always called, and that function is responsible for popping the macro stack. Due to this, Preprocessor::CurTokenLexer can be non-NULL when ~Preprocessor runs. It's a unique_ptr, so it ended up being destructed after ~Preprocessor completed, and its MacroArgs thus got added to the freelist after the code freeing things on the freelist had already completed. The fix is to explicitly call reset() before the freelist processing happens. (See the bug for more notes.) git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@208438 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Lex/Preprocessor.cpp | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp index 56eabf41ff..d263e7d2a0 100644 --- a/lib/Lex/Preprocessor.cpp +++ b/lib/Lex/Preprocessor.cpp @@ -143,14 +143,17 @@ Preprocessor::~Preprocessor() { I->MI.Destroy(); // Free any cached macro expanders. + // This populates MacroArgCache, so all TokenLexers need to be destroyed + // before the code below that frees up the MacroArgCache list. for (unsigned i = 0, e = NumCachedTokenLexers; i != e; ++i) delete TokenLexerCache[i]; + CurTokenLexer.reset(); for (DeserializedMacroInfoChain *I = DeserialMIChainHead ; I ; I = I->Next) I->MI.Destroy(); // Free any cached MacroArgs. - for (MacroArgs *ArgList = MacroArgCache; ArgList; ) + for (MacroArgs *ArgList = MacroArgCache; ArgList;) ArgList = ArgList->deallocate(); // Release pragma information. -- 2.40.0