- //===- llvm/Support/Atomic.h - Atomic Operations -----------------*- 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 
- // 
- //===----------------------------------------------------------------------===// 
- // 
- // This file declares the llvm::sys atomic operations. 
- // 
- // DO NOT USE IN NEW CODE! 
- // 
- // New code should always rely on the std::atomic facilities in C++11. 
- // 
- //===----------------------------------------------------------------------===// 
-   
- #ifndef LLVM_SUPPORT_ATOMIC_H 
- #define LLVM_SUPPORT_ATOMIC_H 
-   
- #include "llvm/Support/DataTypes.h" 
-   
- // Windows will at times define MemoryFence. 
- #ifdef MemoryFence 
- #undef MemoryFence 
- #endif 
-   
- namespace llvm { 
-   namespace sys { 
-     void MemoryFence(); 
-   
- #ifdef _MSC_VER 
-     typedef long cas_flag; 
- #else 
-     typedef uint32_t cas_flag; 
- #endif 
-     cas_flag CompareAndSwap(volatile cas_flag* ptr, 
-                             cas_flag new_value, 
-                             cas_flag old_value); 
-   } 
- } 
-   
- #endif 
-