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Re: Fwd: Objective-C and C99 strict aliasing
On Fri, Apr 10, 2009 at 3:41 AM, Ian Lance Taylor <iant@google.com> wrote:
> John Engelhart <john.engelhart@gmail.com> writes:
>
>> The easiest, and I think safest, course of action would be to add a
>> line in c_common_get_alias_set similar to the one I suggested. ?That
>> is, if it is a pointer to something that looks even remotely like an
>> objective-c "object", then just assume that it can alias anything.
>>
>> Any recommendations on what to do next? ?Filing a bug seems like the
>> step, I just wanted to see if I had missed something in my analysis of
>> the problem.
>
> Since you have a patch, you can just send it to gcc-patches@gcc.gnu.org
> with a ChangeLog entry (see many existing messages on gcc-patches). ?It
> would be very good if you also had a test case to add to the testsuite.
Note that I think that ObjC should be fine (assuming it is a completely
statically typed language) if it properly maintains BINFO records. At least
this is how it works in C++, see record_component_aliases in alias.c.
If ObjC is really dynamically typed then TBAA is indeed doomed.
Richard.