1 //===-- Atomic.cpp - Atomic Operations --------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements atomic operations. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Support/Atomic.h" 15 #include "llvm/Config/llvm-config.h" 16 17 using namespace llvm; 18 19 #if defined(_MSC_VER) 20 #include <Intrin.h> 21 #include <windows.h> 22 #undef MemoryFence 23 #endif 24 25 #if defined(__GNUC__) || (defined(__IBMCPP__) && __IBMCPP__ >= 1210) 26 #define GNU_ATOMICS 27 #endif 28 29 void sys::MemoryFence() { 30 #if LLVM_HAS_ATOMICS == 0 31 return; 32 #else 33 # if defined(GNU_ATOMICS) 34 __sync_synchronize(); 35 # elif defined(_MSC_VER) 36 MemoryBarrier(); 37 # else 38 # error No memory fence implementation for your platform! 39 # endif 40 #endif 41 } 42 43 sys::cas_flag sys::CompareAndSwap(volatile sys::cas_flag* ptr, 44 sys::cas_flag new_value, 45 sys::cas_flag old_value) { 46 #if LLVM_HAS_ATOMICS == 0 47 sys::cas_flag result = *ptr; 48 if (result == old_value) 49 *ptr = new_value; 50 return result; 51 #elif defined(GNU_ATOMICS) 52 return __sync_val_compare_and_swap(ptr, old_value, new_value); 53 #elif defined(_MSC_VER) 54 return InterlockedCompareExchange(ptr, new_value, old_value); 55 #else 56 # error No compare-and-swap implementation for your platform! 57 #endif 58 } 59 60 sys::cas_flag sys::AtomicIncrement(volatile sys::cas_flag* ptr) { 61 #if LLVM_HAS_ATOMICS == 0 62 ++(*ptr); 63 return *ptr; 64 #elif defined(GNU_ATOMICS) 65 return __sync_add_and_fetch(ptr, 1); 66 #elif defined(_MSC_VER) 67 return InterlockedIncrement(ptr); 68 #else 69 # error No atomic increment implementation for your platform! 70 #endif 71 } 72 73 sys::cas_flag sys::AtomicDecrement(volatile sys::cas_flag* ptr) { 74 #if LLVM_HAS_ATOMICS == 0 75 --(*ptr); 76 return *ptr; 77 #elif defined(GNU_ATOMICS) 78 return __sync_sub_and_fetch(ptr, 1); 79 #elif defined(_MSC_VER) 80 return InterlockedDecrement(ptr); 81 #else 82 # error No atomic decrement implementation for your platform! 83 #endif 84 } 85 86 sys::cas_flag sys::AtomicAdd(volatile sys::cas_flag* ptr, sys::cas_flag val) { 87 #if LLVM_HAS_ATOMICS == 0 88 *ptr += val; 89 return *ptr; 90 #elif defined(GNU_ATOMICS) 91 return __sync_add_and_fetch(ptr, val); 92 #elif defined(_MSC_VER) 93 return InterlockedExchangeAdd(ptr, val) + val; 94 #else 95 # error No atomic add implementation for your platform! 96 #endif 97 } 98 99 sys::cas_flag sys::AtomicMul(volatile sys::cas_flag* ptr, sys::cas_flag val) { 100 sys::cas_flag original, result; 101 do { 102 original = *ptr; 103 result = original * val; 104 } while (sys::CompareAndSwap(ptr, result, original) != original); 105 106 return result; 107 } 108 109 sys::cas_flag sys::AtomicDiv(volatile sys::cas_flag* ptr, sys::cas_flag val) { 110 sys::cas_flag original, result; 111 do { 112 original = *ptr; 113 result = original / val; 114 } while (sys::CompareAndSwap(ptr, result, original) != original); 115 116 return result; 117 } 118
