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Re: libsanitizer mege from upstream r169371
Yeah, but then there will be all that additional __sync_synchronize(),
that are not needed if we use __atomic. And on the other hand, if we
have that __sync_synchronize(), then we do not need __atomic...
On Wed, Dec 5, 2012 at 4:57 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Wed, Dec 05, 2012 at 04:53:44PM +0400, Dmitry Vyukov wrote:
>> On Wed, Dec 5, 2012 at 4:42 PM, Jakub Jelinek <jakub@redhat.com> wrote:
>> > On Wed, Dec 05, 2012 at 03:13:20PM +0400, Dmitry Vyukov wrote:
>> >> I hope I addressed all your comments in this revision.
>> >> I've fixed nand atomic operation, made atomic operations atomic again
>> >> and added visibility attribute to interface functions.
>> >
>> > Mostly, still, __sync_lock_test_and_set isn't full barrier unlike most other
>> > __sync_* builtins, so either you'd need to use __atomic_exchange_n if
>> > available (you can e.g. guard it with #ifdef __ATOMIC_SEQ_CST), or
>> > if not available also use __sync_synchronize ().
>>
>>
>> __atomic_xxx are available since gcc 4.7 and we use gcc 4.4 on some
>> bots. I do not want to clutter the code with macros too much.
>
> Well, one option would be just a single #ifdef somewhere,
> #ifndef __ATOMIC_SEQ_CST
> #define __ATOMIC_RELEASE 0
> ...
> #define __atomic_...(...) __sync_...(...)
> ...
> #endif
> i.e. implement __atomic_* as macros using __sync_* if not available,
> then just use __atomic_* in the code everywhere.
>
> Jakub