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
MemoryFence()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
CompareAndSwap(volatile sys::cas_flag * ptr,sys::cas_flag new_value,sys::cas_flag old_value)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
AtomicIncrement(volatile sys::cas_flag * ptr)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
AtomicDecrement(volatile sys::cas_flag * ptr)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
AtomicAdd(volatile sys::cas_flag * ptr,sys::cas_flag val)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
AtomicMul(volatile sys::cas_flag * ptr,sys::cas_flag val)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
AtomicDiv(volatile sys::cas_flag * ptr,sys::cas_flag val)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