Reland "Implement C++11-style GCC builtin atomic ops"
Fixed the crasher in it.
diff --git a/src/hb-atomic-private.hh b/src/hb-atomic-private.hh
index 1496002..02cf6f3 100644
--- a/src/hb-atomic-private.hh
+++ b/src/hb-atomic-private.hh
@@ -46,21 +46,37 @@
/* Defined externally, i.e. in config.h; must have typedef'ed hb_atomic_int_impl_t as well. */
+#elif !defined(HB_NO_MT) && defined(__ATOMIC_ACQUIRE)
+
+/* C++11-style GCC primitives. */
+
+typedef int hb_atomic_int_impl_t;
+#define hb_atomic_int_impl_add(AI, V) __atomic_fetch_add (&(AI), (V), __ATOMIC_ACQ_REL)
+
+#define hb_atomic_ptr_impl_get(P) __atomic_load_n ((P), __ATOMIC_ACQUIRE)
+static inline bool
+_hb_atomic_ptr_impl_cmplexch (const void **P, const void *O_, const void *N)
+{
+ const void *O = O_; // Need lvalue
+ return __atomic_compare_exchange_n ((void **) P, (void **) &O, (void *) N, true, __ATOMIC_ACQ_REL, __ATOMIC_RELAXED);
+}
+#define hb_atomic_ptr_impl_cmpexch(P,O,N) (_hb_atomic_ptr_impl_cmplexch ((const void **) (P), (O), (N)))
+
#elif !defined(HB_NO_MT) && __cplusplus >= 201103L
-/* Prefer C++11 atomics. */
+/* C++11 atomics. */
#include <atomic>
typedef int hb_atomic_int_impl_t;
-#define hb_atomic_int_impl_add(AI, V) (reinterpret_cast<std::atomic<int> *> (&AI)->fetch_add (V, std::memory_order_acq_rel))
+#define hb_atomic_int_impl_add(AI, V) (reinterpret_cast<std::atomic<int> *> (&AI)->fetch_add ((V), std::memory_order_acq_rel))
#define hb_atomic_ptr_impl_get(P) (reinterpret_cast<std::atomic<void*> *> (P)->load (std::memory_order_acquire))
static inline bool
_hb_atomic_ptr_impl_cmplexch (const void **P, const void *O_, const void *N)
{
const void *O = O_; // Need lvalue
- return reinterpret_cast<std::atomic<const void*> *> (P)->compare_exchange_weak ((O), (N), std::memory_order_acq_rel);
+ return reinterpret_cast<std::atomic<const void*> *> (P)->compare_exchange_weak (O, N, std::memory_order_acq_rel, std::memory_order_relaxed);
}
#define hb_atomic_ptr_impl_cmpexch(P,O,N) (_hb_atomic_ptr_impl_cmplexch ((const void **) (P), (O), (N)))
