Re: [boost] [thread] Address sanitizer failures on marshall-mac

Subject: Re: [boost] [thread] Address sanitizer failures on marshall-mac
From: Jonathan Wakely (jwakely.boost_at_[hidden])
Date: 2014-03-09 06:31:00

On 8 March 2014 18:34, Niall Douglas wrote:
> On 8 Mar 2014 at 18:29, Jonathan Wakely wrote:
>
>> The new version is present in both Clang and GCC, and if you use those
>> compilers' built-in atomic operations (either the older __sync_xxxx or
>> newer __atomic_xxx intrinsics) then tsan should understand them and
>> need no instrumentation.
>
> Can tsan understand when an atomic is being used for serialisation? I
> can see a CAS lock being heuristically determined, but some of the
> fancier semaphore based techniques surely need some explicit markup.

I believe it can, because it knows that an atomic store with
memory_order_release in one thread and a load with
memory_order_acquire in another thread implies an ordering, and so can
tell there is no race.

I don't think tsan v2 even supports any explicit markup, so you
couldn't use it if you wanted to.