Boost C++ Libraries: Ticket #6782: call_once uses incorrect barrier intrinsic on Visual Studio

owner, status changed

viboes — Mon, 28 May 2012 15:54:13 GMT

owner changed from Anthony Williams to viboes
status new → assigned

Could you provide a test that proves the issue. And a patch to solve it?

viboes — Sun, 03 Mar 2013 23:18:08 GMT

wouldn't be enough to remove these lines and let the implementation using boost/detail/interlocked.hpp?

#ifdef BOOST_MSVC
extern "C" void _ReadWriteBarrier(void);
#pragma intrinsic(_ReadWriteBarrier)
namespace boost
{
    namespace detail
    {
        inline long interlocked_read_acquire(long volatile* x) BOOST_NOEXCEPT
        {
            long const res=*x;
            _ReadWriteBarrier();
            return res;
        }
        inline void* interlocked_read_acquire(void* volatile* x) BOOST_NOEXCEPT
        {
            void* const res=*x;
            _ReadWriteBarrier();
            return res;
        }
        inline void interlocked_write_release(long volatile* x,long value) BOOST_NOEXCEPT
        {
            _ReadWriteBarrier();
            *x=value;
        }
        inline void interlocked_write_release(void* volatile* x,void* value) BOOST_NOEXCEPT
        {
            _ReadWriteBarrier();
            *x=value;
        }
    }
}
#else
#endif

Niall Douglas — Sat, 04 Oct 2014 18:49:45 GMT

I believe Boost requires VS2005 minimum now, so I have removed the ReadWriteBarrier completely as volatile reads always acquire and volatile writes always release. MSVC generates the appropriate acquire-release opcodes on ARM, and on x86 they are unnecessary as all loads acquire and all stores release. This ticket can now be closed. Niall

milestone changed

viboes — Sun, 05 Oct 2014 06:49:13 GMT

milestone To Be Determined → Boost 1.57.0

https://github.com/boostorg/thread/commit/6fe7f44ea047b5f4c0182fa73fb1755af0bcf11a

status changed; resolution set

viboes — Sat, 11 Oct 2014 05:22:52 GMT

status assigned → closed
resolution → fixed

https://github.com/boostorg/thread/commit/6fe7f44ea047b5f4c0182fa73fb1755af0bcf11a