Merge branch 'mergelibs12' into main

1 files changed, 92 insertions, 18 deletions

diff --git a/contrib/libs/cxxsupp/libcxxrt/atomic.h b/contrib/libs/cxxsupp/libcxxrt/atomic.h
index afdbdd04d5d..701d05337cf 100644
--- a/contrib/libs/cxxsupp/libcxxrt/atomic.h
+++ b/contrib/libs/cxxsupp/libcxxrt/atomic.h
@@ -1,28 +1,102 @@
+
 #ifndef __has_builtin
-#define __has_builtin(x) 0
+#	define __has_builtin(x) 0
 #endif
 #ifndef __has_feature
-#define __has_feature(x) 0
+#	define __has_feature(x) 0
+#endif
+#ifndef __has_extension
+#	define __has_extension(x) 0
+#endif
+
+#if !__has_extension(c_atomic)
+#	define _Atomic(T) T
 #endif
-/**
- * Swap macro that enforces a happens-before relationship with a corresponding
- * ATOMIC_LOAD.
- */
 #if __has_builtin(__c11_atomic_exchange)
-#define ATOMIC_SWAP(addr, val)\
-	__c11_atomic_exchange(reinterpret_cast<_Atomic(__typeof__(val))*>(addr), val, __ATOMIC_ACQ_REL)
-#elif __has_builtin(__sync_swap)
-#define ATOMIC_SWAP(addr, val)\
-	__sync_swap(addr, val)
+#	define ATOMIC_BUILTIN(name) __c11_atomic_##name
 #else
-#define ATOMIC_SWAP(addr, val)\
-	__sync_lock_test_and_set(addr, val)
+#	define ATOMIC_BUILTIN(name) __atomic_##name##_n
 #endif
 
-#if __has_builtin(__c11_atomic_load)
-#define ATOMIC_LOAD(addr)\
-	__c11_atomic_load(reinterpret_cast<_Atomic(__typeof__(*addr))*>(addr), __ATOMIC_ACQUIRE)
+namespace
+{
+	/**
+	 * C++11 memory orders.  We only need a subset of them.
+	 */
+	enum memory_order
+	{
+		/**
+		 * Acquire order.
+		 */
+		acquire = __ATOMIC_ACQUIRE,
+
+		/**
+		 * Release order.
+		 */
+		release = __ATOMIC_RELEASE,
+
+		/**
+		 * Sequentially consistent memory ordering.
+		 */
+		seqcst = __ATOMIC_SEQ_CST
+	};
+
+	/**
+	 * Atomic, implements a subset of `std::atomic`.
+	 */
+	template<typename T>
+	class atomic
+	{
+		/**
+		 * The underlying value.  Use C11 atomic qualification if available.
+		 */
+		_Atomic(T) val;
+
+		public:
+		/**
+		 * Constructor, takes a value.
+		 */
+		atomic(T init) : val(init) {}
+
+		/**
+		 * Atomically load with the specified memory order.
+		 */
+		T load(memory_order order = memory_order::seqcst)
+		{
+			return ATOMIC_BUILTIN(load)(&val, order);
+		}
+
+		/**
+		 * Atomically store with the specified memory order.
+		 */
+		void store(T v, memory_order order = memory_order::seqcst)
+		{
+			return ATOMIC_BUILTIN(store)(&val, v, order);
+		}
+
+		/**
+		 * Atomically exchange with the specified memory order.
+		 */
+		T exchange(T v, memory_order order = memory_order::seqcst)
+		{
+			return ATOMIC_BUILTIN(exchange)(&val, v, order);
+		}
+
+		/**
+		 * Atomically exchange with the specified memory order.
+		 */
+		bool compare_exchange(T &          expected,
+		                      T            desired,
+		                      memory_order order = memory_order::seqcst)
+		{
+#if __has_builtin(__c11_atomic_compare_exchange_strong)
+			return __c11_atomic_compare_exchange_strong(
+			  &val, &expected, desired, order, order);
 #else
-#define ATOMIC_LOAD(addr)\
-	(__sync_synchronize(), *addr)
+			return __atomic_compare_exchange_n(
+			  &val, &expected, desired, true, order, order);
 #endif
+		}
+	};
+} // namespace
+#undef ATOMIC_BUILTIN