On 05.10.2010 20:37, Douglas Gregor wrote: > Author: dgregor > Date: Tue Oct 5 13:37:06 2010 > New Revision: 115647 > > URL: http://llvm.org/viewvc/llvm-project?rev=115647&view=rev > Log: > Fix a marvelous chained AST writing bug, where we end up with the > following amusing sequence: > - AST writing schedules writing a type X* that it had never seen > before > - AST writing starts writing another declaration, ends up > deserializing X* from a prior AST file. Now we have two type IDs for > the same type! > - AST writer tries to write X*. It only has the lower-numbered ID > from the the prior AST file, so references to the higher-numbered ID > that was scheduled for writing go off into lalaland. > > To fix this, keep the higher-numbered ID so we end up writing the type > twice. Since this issue occurs so rarely, and type records are > generally rather small, I deemed this better than the alternative: to > keep a separate mapping from the higher-numbered IDs to the > lower-numbered IDs, which we would end up having to check whenever we > want to deserialize any type. >
Well, there's the really nice but complicated version: dump ASTContext's uniqueing table to AST files so that we can do uniqueing while considering types not yet loaded. :-) Sebastian _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
