include/llvm/Support/Atomic.h

   1 //===- llvm/Support/Atomic.h - Atomic Operations -----------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file declares the llvm::sys atomic operations.
  10 //
  11 // DO NOT USE IN NEW CODE!
  12 //
  13 // New code should always rely on the std::atomic facilities in C++11.
  14 //
  15 //===----------------------------------------------------------------------===//
  16
  17 #ifndef LLVM_SUPPORT_ATOMIC_H
  18 #define LLVM_SUPPORT_ATOMIC_H
  19
  20 #include "llvm/Support/DataTypes.h"
  21
  22 // Windows will at times define MemoryFence.
  23 #ifdef MemoryFence
  24 #undef MemoryFence
  25 #endif
  26
  27 namespace llvm {
  28   namespace sys {
  29     void MemoryFence();
  30
  31 #ifdef _MSC_VER
  32     typedef long cas_flag;
  33 #else
  34     typedef uint32_t cas_flag;
  35 #endif
  36     cas_flag CompareAndSwap(volatile cas_flag* ptr,
  37                             cas_flag new_value,
  38                             cas_flag old_value);
  39   }
  40 }
  41
  42 #endif