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 header file implements atomic operations.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "llvm/Support/Atomic.h"
15 #include "llvm/Config/llvm-config.h"
16 #if defined(ANDROID_TARGET_BUILD)
17 # include "sys/atomics.h"
18 #endif
19
20 using namespace llvm;
21
22 #if defined(_MSC_VER)
23 #include <windows.h>
24 #undef MemoryFence
25 #endif
26
MemoryFence()27 void sys::MemoryFence() {
28 #if LLVM_HAS_ATOMICS == 0
29 return;
30 #else
31 # if defined(__GNUC__)
32 __sync_synchronize();
33 # elif defined(_MSC_VER)
34 MemoryBarrier();
35 # else
36 # error No memory fence implementation for your platform!
37 # endif
38 #endif
39 }
40
CompareAndSwap(volatile sys::cas_flag * ptr,sys::cas_flag new_value,sys::cas_flag old_value)41 sys::cas_flag sys::CompareAndSwap(volatile sys::cas_flag* ptr,
42 sys::cas_flag new_value,
43 sys::cas_flag old_value) {
44 #if LLVM_HAS_ATOMICS == 0
45 sys::cas_flag result = *ptr;
46 if (result == old_value)
47 *ptr = new_value;
48 return result;
49 #elif defined(ANDROID_TARGET_BUILD)
50 return __atomic_cmpxchg(old_value, new_value, (volatile int*)ptr);
51 #elif defined(__GNUC__)
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(ANDROID_TARGET_BUILD)
65 return __atomic_inc((volatile int*)ptr);
66 #elif defined(__GNUC__)
67 return __sync_add_and_fetch(ptr, 1);
68 #elif defined(_MSC_VER)
69 return InterlockedIncrement(ptr);
70 #else
71 # error No atomic increment implementation for your platform!
72 #endif
73 }
74
AtomicDecrement(volatile sys::cas_flag * ptr)75 sys::cas_flag sys::AtomicDecrement(volatile sys::cas_flag* ptr) {
76 #if LLVM_HAS_ATOMICS == 0
77 --(*ptr);
78 return *ptr;
79 #elif defined(ANDROID_TARGET_BUILD)
80 return __atomic_dec((volatile int*)ptr);
81 #elif defined(__GNUC__)
82 return __sync_sub_and_fetch(ptr, 1);
83 #elif defined(_MSC_VER)
84 return InterlockedDecrement(ptr);
85 #else
86 # error No atomic decrement implementation for your platform!
87 #endif
88 }
89
AtomicAdd(volatile sys::cas_flag * ptr,sys::cas_flag val)90 sys::cas_flag sys::AtomicAdd(volatile sys::cas_flag* ptr, sys::cas_flag val) {
91 #if LLVM_HAS_ATOMICS == 0
92 *ptr += val;
93 return *ptr;
94 #elif defined(ANDROID_TARGET_BUILD)
95 sys::cas_flag original, result;
96 do {
97 original = *ptr;
98 result = original + val;
99 } while (__atomic_cmpxchg(original, result, (volatile int*)ptr) != original);
100 return result;
101 #elif defined(__GNUC__)
102 return __sync_add_and_fetch(ptr, val);
103 #elif defined(_MSC_VER)
104 return InterlockedExchangeAdd(ptr, val) + val;
105 #else
106 # error No atomic add implementation for your platform!
107 #endif
108 }
109
AtomicMul(volatile sys::cas_flag * ptr,sys::cas_flag val)110 sys::cas_flag sys::AtomicMul(volatile sys::cas_flag* ptr, sys::cas_flag val) {
111 sys::cas_flag original, result;
112 do {
113 original = *ptr;
114 result = original * val;
115 } while (sys::CompareAndSwap(ptr, result, original) != original);
116
117 return result;
118 }
119
AtomicDiv(volatile sys::cas_flag * ptr,sys::cas_flag val)120 sys::cas_flag sys::AtomicDiv(volatile sys::cas_flag* ptr, sys::cas_flag val) {
121 sys::cas_flag original, result;
122 do {
123 original = *ptr;
124 result = original / val;
125 } while (sys::CompareAndSwap(ptr, result, original) != original);
126
127 return result;
128 }
129