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 = _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