Use paired failure order during atomic lazy init

bignerdranch · Mar 26, 2020 · 869f871 · 869f871
1 parent 66df0ae
commit 869f871
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Showing 2 changed files with 5 additions and 5 deletions.
diff --git a/Sources/CAtomics/include/CAtomics.h b/Sources/CAtomics/include/CAtomics.h
@@ -63,8 +63,8 @@ const void *_Nullable bnr_atomic_exchange(bnr_atomic_ptr_t target, const void *_
 }
 
 BNR_ATOMIC_INLINE BNR_ATOMIC_WARN_UNUSED_RESULT
-bool bnr_atomic_compare_and_swap(bnr_atomic_ptr_t target, const void *_Nullable expected, const void *_Nullable desired, bnr_atomic_memory_order_t order) {
-    return atomic_compare_exchange_strong_explicit((const void *_Atomic *)target, &expected, desired, order, memory_order_relaxed);
+bool bnr_atomic_compare_and_swap(bnr_atomic_ptr_t target, const void *_Nullable expected, const void *_Nullable desired, bnr_atomic_memory_order_t order, bnr_atomic_memory_order_t failureOrder) {
+    return atomic_compare_exchange_strong_explicit((const void *_Atomic *)target, &expected, desired, order, failureOrder);
 }
 
 BNR_ATOMIC_INLINE BNR_ATOMIC_WARN_UNUSED_RESULT

diff --git a/Sources/Deferred/Atomics.swift b/Sources/Deferred/Atomics.swift
@@ -65,10 +65,10 @@ func bnr_atomic_exchange(_ target: bnr_atomic_ptr_t, _ desired: UnsafeRawPointer
     return old
 }
 
-func bnr_atomic_compare_and_swap(_ target: bnr_atomic_ptr_t, _ expected: UnsafeRawPointer?, _ desired: UnsafeRawPointer?, _ order: bnr_atomic_memory_order_t) -> Bool {
+func bnr_atomic_compare_and_swap(_ target: bnr_atomic_ptr_t, _ expected: UnsafeRawPointer?, _ desired: UnsafeRawPointer?, _ order: bnr_atomic_memory_order_t, _ failureOrder: bnr_atomic_memory_order_t) -> Bool {
     var expected = expected
     var desired = desired
-    return DarwinAtomics.shared.compareExchange(MemoryLayout<UnsafeRawPointer?>.size, target, &expected, &desired, order, .relaxed)
+    return DarwinAtomics.shared.compareExchange(MemoryLayout<UnsafeRawPointer?>.size, target, &expected, &desired, order, failureOrder)
 }
 
 func bnr_atomic_load_and_wait(_ target: bnr_atomic_ptr_t) -> UnsafeRawPointer {
@@ -119,7 +119,7 @@ func bnr_atomic_store<T: AnyObject>(_ target: UnsafeMutablePointer<T?>, _ desire
 func bnr_atomic_initialize_once<T: AnyObject>(_ target: UnsafeMutablePointer<T?>, _ desired: T) -> Bool {
     let rawTarget = UnsafeMutableRawPointer(target).assumingMemoryBound(to: UnsafeRawPointer?.self)
     let retainedDesired = Unmanaged.passRetained(desired)
-    let wonRace = bnr_atomic_compare_and_swap(rawTarget, nil, retainedDesired.toOpaque(), .acq_rel)
+    let wonRace = bnr_atomic_compare_and_swap(rawTarget, nil, retainedDesired.toOpaque(), .acq_rel, .acquire)
     if !wonRace {
         retainedDesired.release()
     }