diff options
Diffstat (limited to 'contrib/libc++/src/memory.cpp')
| -rw-r--r-- | contrib/libc++/src/memory.cpp | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/contrib/libc++/src/memory.cpp b/contrib/libc++/src/memory.cpp index 8a4eb34..66fb143 100644 --- a/contrib/libc++/src/memory.cpp +++ b/contrib/libc++/src/memory.cpp @@ -13,24 +13,28 @@ #include "mutex" #include "thread" #endif +#include "support/atomic_support.h" _LIBCPP_BEGIN_NAMESPACE_STD namespace { +// NOTE: Relaxed and acq/rel atomics (for increment and decrement respectively) +// should be sufficient for thread safety. +// See https://llvm.org/bugs/show_bug.cgi?id=22803 template <class T> inline T increment(T& t) _NOEXCEPT { - return __sync_add_and_fetch(&t, 1); + return __libcpp_atomic_add(&t, 1, _AO_Relaxed); } template <class T> inline T decrement(T& t) _NOEXCEPT { - return __sync_add_and_fetch(&t, -1); + return __libcpp_atomic_add(&t, -1, _AO_Acq_Rel); } } // namespace @@ -99,14 +103,13 @@ __shared_weak_count::__release_weak() _NOEXCEPT __shared_weak_count* __shared_weak_count::lock() _NOEXCEPT { - long object_owners = __shared_owners_; + long object_owners = __libcpp_atomic_load(&__shared_owners_); while (object_owners != -1) { - if (__sync_bool_compare_and_swap(&__shared_owners_, - object_owners, - object_owners+1)) + if (__libcpp_atomic_compare_exchange(&__shared_owners_, + &object_owners, + object_owners+1)) return this; - object_owners = __shared_owners_; } return 0; } |
