llvm/libc/src/__support/CPP/atomic.h

//===-- A simple equivalent of std::atomic ----------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIBC_SRC___SUPPORT_CPP_ATOMIC_H
#define LLVM_LIBC_SRC___SUPPORT_CPP_ATOMIC_H

#include "src/__support/macros/attributes.h"
#include "src/__support/macros/config.h"
#include "src/__support/macros/properties/architectures.h"

#include "type_traits.h"

namespace LIBC_NAMESPACE_DECL {
namespace cpp {

enum class MemoryOrder : int { … };

// These are a clang extension, see the clang documenation for more information:
// https://clang.llvm.org/docs/LanguageExtensions.html#scoped-atomic-builtins.
enum class MemoryScope : int { … };

template <typename T> struct Atomic { … };

// Issue a thread fence with the given memory ordering.
LIBC_INLINE void atomic_thread_fence([[maybe_unused]] MemoryOrder mem_ord) { … }

// Establishes memory synchronization ordering of non-atomic and relaxed atomic
// accesses, as instructed by order, between a thread and a signal handler
// executed on the same thread. This is equivalent to atomic_thread_fence,
// except no instructions for memory ordering are issued. Only reordering of
// the instructions by the compiler is suppressed as order instructs.
LIBC_INLINE void atomic_signal_fence([[maybe_unused]] MemoryOrder mem_ord) { … }

} // namespace cpp
} // namespace LIBC_NAMESPACE_DECL

#endif // LLVM_LIBC_SRC___SUPPORT_CPP_ATOMIC_H