Differential D19566 Diff 55036 contrib/libcxxabi/src/include/atomic_support.h

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contrib/libcxxabi/src/include/atomic_support.h

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				//===----------------------------------------------------------------------===////
				//
				// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
				// See https://llvm.org/LICENSE.txt for license information.
				// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
				//
				//===----------------------------------------------------------------------===////

				// FIXME: This file is copied from libcxx/src/include/atomic_support.h. Instead
				// of duplicating the file in libc++abi we should require that the libc++
				// sources are available when building libc++abi.

				#ifndef ATOMIC_SUPPORT_H
				#define ATOMIC_SUPPORT_H

				#include "__config"
				#include "memory" // for __libcpp_relaxed_load

				#if defined(__clang__) && __has_builtin(__atomic_load_n) \
				&& __has_builtin(__atomic_store_n) \
				&& __has_builtin(__atomic_add_fetch) \
				&& __has_builtin(__atomic_exchange_n) \
				&& __has_builtin(__atomic_compare_exchange_n) \
				&& defined(__ATOMIC_RELAXED) \
				&& defined(__ATOMIC_CONSUME) \
				&& defined(__ATOMIC_ACQUIRE) \
				&& defined(__ATOMIC_RELEASE) \
				&& defined(__ATOMIC_ACQ_REL) \
				&& defined(__ATOMIC_SEQ_CST)
				# define _LIBCXXABI_HAS_ATOMIC_BUILTINS
				#elif !defined(__clang__) && defined(_GNUC_VER) && _GNUC_VER >= 407
				# define _LIBCXXABI_HAS_ATOMIC_BUILTINS
				#endif

				#if !defined(_LIBCXXABI_HAS_ATOMIC_BUILTINS) && !defined(_LIBCXXABI_HAS_NO_THREADS)
				# if defined(_LIBCPP_WARNING)
				_LIBCPP_WARNING("Building libc++ without __atomic builtins is unsupported")
				# else
				# warning Building libc++ without __atomic builtins is unsupported
				# endif
				#endif

				_LIBCPP_BEGIN_NAMESPACE_STD

				namespace {

				#if defined(_LIBCXXABI_HAS_ATOMIC_BUILTINS) && !defined(_LIBCXXABI_HAS_NO_THREADS)

				enum __libcpp_atomic_order {
				_AO_Relaxed = __ATOMIC_RELAXED,
				_AO_Consume = __ATOMIC_CONSUME,
				_AO_Acquire = __ATOMIC_ACQUIRE,
				_AO_Release = __ATOMIC_RELEASE,
				_AO_Acq_Rel = __ATOMIC_ACQ_REL,
				_AO_Seq = __ATOMIC_SEQ_CST
				};

				template <class _ValueType, class _FromType>
				inline _LIBCPP_INLINE_VISIBILITY
				void __libcpp_atomic_store(_ValueType* __dest, _FromType __val,
				int __order = _AO_Seq)
				{
				__atomic_store_n(__dest, __val, __order);
				}

				template <class _ValueType, class _FromType>
				inline _LIBCPP_INLINE_VISIBILITY
				void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val)
				{
				__atomic_store_n(__dest, __val, _AO_Relaxed);
				}

				template <class _ValueType>
				inline _LIBCPP_INLINE_VISIBILITY
				_ValueType __libcpp_atomic_load(_ValueType const* __val,
				int __order = _AO_Seq)
				{
				return __atomic_load_n(__val, __order);
				}

				template <class _ValueType, class _AddType>
				inline _LIBCPP_INLINE_VISIBILITY
				_ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a,
				int __order = _AO_Seq)
				{
				return __atomic_add_fetch(__val, __a, __order);
				}

				template <class _ValueType>
				inline _LIBCPP_INLINE_VISIBILITY
				_ValueType __libcpp_atomic_exchange(_ValueType* __target,
				_ValueType __value, int __order = _AO_Seq)
				{
				return __atomic_exchange_n(__target, __value, __order);
				}

				template <class _ValueType>
				inline _LIBCPP_INLINE_VISIBILITY
				bool __libcpp_atomic_compare_exchange(_ValueType* __val,
				_ValueType* __expected, _ValueType __after,
				int __success_order = _AO_Seq,
				int __fail_order = _AO_Seq)
				{
				return __atomic_compare_exchange_n(__val, __expected, __after, true,
				__success_order, __fail_order);
				}

				#else // _LIBCPP_HAS_NO_THREADS

				enum __libcpp_atomic_order {
				_AO_Relaxed,
				_AO_Consume,
				_AO_Acquire,
				_AO_Release,
				_AO_Acq_Rel,
				_AO_Seq
				};

				template <class _ValueType, class _FromType>
				inline _LIBCPP_INLINE_VISIBILITY
				void __libcpp_atomic_store(_ValueType* __dest, _FromType __val,
				int = 0)
				{
				*__dest = __val;
				}

				template <class _ValueType, class _FromType>
				inline _LIBCPP_INLINE_VISIBILITY
				void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val)
				{
				*__dest = __val;
				}

				template <class _ValueType>
				inline _LIBCPP_INLINE_VISIBILITY
				_ValueType __libcpp_atomic_load(_ValueType const* __val,
				int = 0)
				{
				return *__val;
				}

				template <class _ValueType, class _AddType>
				inline _LIBCPP_INLINE_VISIBILITY
				_ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a,
				int = 0)
				{
				return *__val += __a;
				}

				template <class _ValueType>
				inline _LIBCPP_INLINE_VISIBILITY
				_ValueType __libcpp_atomic_exchange(_ValueType* __target,
				_ValueType __value, int __order = _AO_Seq)
				{
				_ValueType old = *__target;
				*__target = __value;
				return old;
				}

				template <class _ValueType>
				inline _LIBCPP_INLINE_VISIBILITY
				bool __libcpp_atomic_compare_exchange(_ValueType* __val,
				_ValueType* __expected, _ValueType __after,
				int = 0, int = 0)
				{
				if (__val == __expected) {
				*__val = __after;
				return true;
				}
				__expected = __val;
				return false;
				}

				#endif // _LIBCPP_HAS_NO_THREADS

				} // end namespace

				_LIBCPP_END_NAMESPACE_STD

				#endif // ATOMIC_SUPPORT_H