[cfe-dev] Atomic operations/builtins and Windows

[Eli Friedman]

On Sun, Sep 25, 2011 at 12:51 PM, Ruben Van Boxem
<vanboxem.ruben at gmail.com> wrote:
> 2011/9/25 Eli Friedman <eli.friedman at gmail.com>
>>
>> On Sun, Sep 25, 2011 at 12:04 PM, Ruben Van Boxem
>> <vanboxem.ruben at gmail.com> wrote:
>> > Hi,
>> >
>> > What is the status/usability of Clang's builtin atomic functions,
>> > especially
>> > on Windows? Are the builtins related to the availability of pthreads or
>> > not?
>> >
>> > It seems libc++ uses these builtins, but for *-*-mingw*, they're
>> > undeclared
>> > :(
>> >
>> > Can Clang "tap into" the GCC implementations?
>>
>> Please clarify what exactly you are talking about... which builtins,
>> exactly?
>
> Things documented/proposed? here:
> http://libcxx.llvm.org/atomic_design_a.html
> or http://libcxx.llvm.org/atomic_design_b.html
> or http://libcxx.llvm.org/atomic_design_c.html
> GCC has __sync_* documented here:
> http://gcc.gnu.org/onlinedocs/gcc/Atomic-Builtins.html
>
> I don't know if libc++ <atomic> is meant to be usable yet (I would think it
> is), but the __has_feature(cxx_atomic) is false for my Clang build. I do
> know someone did some work in this regard for Clang. The only discussion on
> this topic I can find right now is dated almost a year ago:
> http://clang-developers.42468.n3.nabble.com/atomic-intrinsics-td1618127i20.html
>
> Ruben
>
> PS: if <atomic> is not meant to be used right now, I'll ignore it
> completely.

<atomic> is not meant to be used right now.  I'm working with Howard
and a couple other people to get it working, but it isn't quite there
yet.

-Eli