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 ().
Also, for the atomic load and store, it would be nice to use __atomic_load_n
and __atomic_store_n if available (as fallback __sync_synchronize (), which
I believe needs to be before resp. after the memory operation depending on
whether it is load or store).
And we'll need to tweak libsanitizer makefiles, so it uses -mcx16 on x86_64
64-bit when compiling that tsan_atomic*.cc, either we just ignore for
libsanitizer the pre-CX16 AMD CPUs, those were just a few initial models
I think, or we'd need to do IFUNC dispatcher, or perhaps just one time
cpuid check that would see if it can do 16-byte atomics or not.
Jakub
