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[Bug libstdc++/54314] [4.8 Regression] undefined references to 'construction vtable for std::ostream-in-std::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >'
- From: "jason at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 28 Jan 2013 15:42:57 +0000
- Subject: [Bug libstdc++/54314] [4.8 Regression] undefined references to 'construction vtable for std::ostream-in-std::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >'
- Auto-submitted: auto-generated
- References: <bug-54314-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54314
--- Comment #27 from Jason Merrill <jason at gcc dot gnu.org> 2013-01-28 15:42:57 UTC ---
(In reply to comment #26)
> 1) Just add the check. We will then miss all devirtualization oppurtunities
> through the construction vtable.
The front end does devirtualization itself for calls within constructors, so
the impact of this isn't likely to be too bad.
> what happens on targets not supporting visibility?
I think that setting DECL_VISIBILITY should do the trick even if it isn't
reflected in the assembly output. I added the DECL_ARTIFICIAL check to
default_assemble_visibility so that this wouldn't cause warnings.
> 3) Perhaps we can use DECL_VALUE_EXPR or somethin similar to keep track of
> the canonical way to reffer into tthe construction vtable? (i.e. by
> reference
> to vtable) We can then lower all direct references to the indirect
> references late, i.e. in expansion?
Hmm, that makes sense.