[cxx-abi-dev] There is no obligation to unique virtual tables

[John McCall]

On Feb 17, 2013, at 1:58 PM, Jason Merrill <jason at redhat.com> wrote:
> On 02/16/2013 08:58 PM, John McCall wrote:
>> GCC stopped even uniquing _ZTS's by
>> default as of GCC 4.5, using a new comparison scheme on all platforms
>> (which, incidentally, I think would be worth documenting as an official
>> alternative, if anyone from GCC would mind describing the rules they use).
> 
> _ZTSs are no less unique now than they were before

> we decided that it was too expensive to use for _ZTSs, so we left them only mostly unique

So... _ZTSs are less unique now than they were before. :)

> For types local to a translation unit we still do pointer comparison.

Out of curiosity, do you try to use pointer comparison for types with hidden visibility, or is it just internal vs. at-any-visibility external?

John.