https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62051
--- Comment #14 from Jason Merrill <jason at gcc dot gnu.org> --- (In reply to Jan Hubicka from comment #13) > this patch adds the logic to gimple-fold.c which makes the offending dtor > non-refeable. It is bit uglier than I hoped for. The reason is that the > dtor itself is COMDAT so it seems perfectly OK to refer it since we can > provide the body, but the body itself refers to vtable that is not output in > the unit. Right. > The patch simply prohibits references to all COMDAT and EXTERN methods and > vtables of types with visibility attributes which will prevent optimizing of > many inlines i.e. in libstdc++. Hmm? This shouldn't affect libstdc++ at all; it doesn't set visibility on individual member functions, only on whole namespaces. This should only affect code that plays these kinds of partial export games. > It still seem to me that the the testcase is sort of invalid because it > provide inline body for the dtor. Agreed, but if it were out-of-line we'd have the same problem with devirt trying to call the dtor directly. > Can we think of better solution (perhaps > validating comdats before using them and checking if symbols they refer to > are referable)? Since the effect should already be well targeted, I don't think we need to work that hard.
