Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 1 | // Copyright 2010 the V8 project authors. All rights reserved. |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 4 | |
| 5 | // The routines exported by this module are subtle. If you use them, even if |
| 6 | // you get the code right, it will depend on careful reasoning about atomicity |
| 7 | // and memory ordering; it will be less readable, and harder to maintain. If |
| 8 | // you plan to use these routines, you should have a good reason, such as solid |
| 9 | // evidence that performance would otherwise suffer, or there being no |
| 10 | // alternative. You should assume only properties explicitly guaranteed by the |
| 11 | // specifications in this file. You are almost certainly _not_ writing code |
| 12 | // just for the x86; if you assume x86 semantics, x86 hardware bugs and |
| 13 | // implementations on other archtectures will cause your code to break. If you |
| 14 | // do not know what you are doing, avoid these routines, and use a Mutex. |
| 15 | // |
| 16 | // It is incorrect to make direct assignments to/from an atomic variable. |
| 17 | // You should use one of the Load or Store routines. The NoBarrier |
| 18 | // versions are provided when no barriers are needed: |
| 19 | // NoBarrier_Store() |
| 20 | // NoBarrier_Load() |
| 21 | // Although there are currently no compiler enforcement, you are encouraged |
| 22 | // to use these. |
| 23 | // |
| 24 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 25 | #ifndef V8_BASE_ATOMICOPS_H_ |
| 26 | #define V8_BASE_ATOMICOPS_H_ |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 27 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 28 | #include <stdint.h> |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 29 | #include "src/base/build_config.h" |
| 30 | |
| 31 | #if defined(_WIN32) && defined(V8_HOST_ARCH_64_BIT) |
| 32 | // windows.h #defines this (only on x64). This causes problems because the |
| 33 | // public API also uses MemoryBarrier at the public name for this fence. So, on |
| 34 | // X64, undef it, and call its documented |
| 35 | // (http://msdn.microsoft.com/en-us/library/windows/desktop/ms684208.aspx) |
| 36 | // implementation directly. |
| 37 | #undef MemoryBarrier |
| 38 | #endif |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 39 | |
| 40 | namespace v8 { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 41 | namespace base { |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 42 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 43 | typedef char Atomic8; |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 44 | typedef int32_t Atomic32; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 45 | #if defined(__native_client__) |
| 46 | typedef int64_t Atomic64; |
| 47 | #elif defined(V8_HOST_ARCH_64_BIT) |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 48 | // We need to be able to go between Atomic64 and AtomicWord implicitly. This |
| 49 | // means Atomic64 and AtomicWord should be the same type on 64-bit. |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 50 | #if defined(__ILP32__) |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 51 | typedef int64_t Atomic64; |
| 52 | #else |
| 53 | typedef intptr_t Atomic64; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 54 | #endif // defined(V8_HOST_ARCH_64_BIT) |
| 55 | #endif // defined(__native_client__) |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 56 | |
| 57 | // Use AtomicWord for a machine-sized pointer. It will use the Atomic32 or |
| 58 | // Atomic64 routines below, depending on your architecture. |
| 59 | typedef intptr_t AtomicWord; |
| 60 | |
| 61 | // Atomically execute: |
| 62 | // result = *ptr; |
| 63 | // if (*ptr == old_value) |
| 64 | // *ptr = new_value; |
| 65 | // return result; |
| 66 | // |
| 67 | // I.e., replace "*ptr" with "new_value" if "*ptr" used to be "old_value". |
| 68 | // Always return the old value of "*ptr" |
| 69 | // |
| 70 | // This routine implies no memory barriers. |
| 71 | Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr, |
| 72 | Atomic32 old_value, |
| 73 | Atomic32 new_value); |
| 74 | |
| 75 | // Atomically store new_value into *ptr, returning the previous value held in |
| 76 | // *ptr. This routine implies no memory barriers. |
| 77 | Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr, Atomic32 new_value); |
| 78 | |
| 79 | // Atomically increment *ptr by "increment". Returns the new value of |
| 80 | // *ptr with the increment applied. This routine implies no memory barriers. |
| 81 | Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, Atomic32 increment); |
| 82 | |
| 83 | Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr, |
| 84 | Atomic32 increment); |
| 85 | |
| 86 | // These following lower-level operations are typically useful only to people |
| 87 | // implementing higher-level synchronization operations like spinlocks, |
| 88 | // mutexes, and condition-variables. They combine CompareAndSwap(), a load, or |
| 89 | // a store with appropriate memory-ordering instructions. "Acquire" operations |
| 90 | // ensure that no later memory access can be reordered ahead of the operation. |
| 91 | // "Release" operations ensure that no previous memory access can be reordered |
| 92 | // after the operation. "Barrier" operations have both "Acquire" and "Release" |
| 93 | // semantics. A MemoryBarrier() has "Barrier" semantics, but does no memory |
| 94 | // access. |
| 95 | Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr, |
| 96 | Atomic32 old_value, |
| 97 | Atomic32 new_value); |
| 98 | Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr, |
| 99 | Atomic32 old_value, |
| 100 | Atomic32 new_value); |
| 101 | |
| 102 | void MemoryBarrier(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 103 | void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value); |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 104 | void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value); |
| 105 | void Acquire_Store(volatile Atomic32* ptr, Atomic32 value); |
| 106 | void Release_Store(volatile Atomic32* ptr, Atomic32 value); |
| 107 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 108 | Atomic8 NoBarrier_Load(volatile const Atomic8* ptr); |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 109 | Atomic32 NoBarrier_Load(volatile const Atomic32* ptr); |
| 110 | Atomic32 Acquire_Load(volatile const Atomic32* ptr); |
| 111 | Atomic32 Release_Load(volatile const Atomic32* ptr); |
| 112 | |
| 113 | // 64-bit atomic operations (only available on 64-bit processors). |
| 114 | #ifdef V8_HOST_ARCH_64_BIT |
| 115 | Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr, |
| 116 | Atomic64 old_value, |
| 117 | Atomic64 new_value); |
| 118 | Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr, Atomic64 new_value); |
| 119 | Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr, Atomic64 increment); |
| 120 | Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr, Atomic64 increment); |
| 121 | |
| 122 | Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr, |
| 123 | Atomic64 old_value, |
| 124 | Atomic64 new_value); |
| 125 | Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr, |
| 126 | Atomic64 old_value, |
| 127 | Atomic64 new_value); |
| 128 | void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value); |
| 129 | void Acquire_Store(volatile Atomic64* ptr, Atomic64 value); |
| 130 | void Release_Store(volatile Atomic64* ptr, Atomic64 value); |
| 131 | Atomic64 NoBarrier_Load(volatile const Atomic64* ptr); |
| 132 | Atomic64 Acquire_Load(volatile const Atomic64* ptr); |
| 133 | Atomic64 Release_Load(volatile const Atomic64* ptr); |
| 134 | #endif // V8_HOST_ARCH_64_BIT |
| 135 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 136 | } // namespace base |
| 137 | } // namespace v8 |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 138 | |
| 139 | // Include our platform specific implementation. |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 140 | #if defined(THREAD_SANITIZER) |
| 141 | #include "src/base/atomicops_internals_tsan.h" |
| 142 | #elif defined(_MSC_VER) && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64) |
| 143 | #include "src/base/atomicops_internals_x86_msvc.h" |
| 144 | #elif defined(__APPLE__) |
| 145 | #include "src/base/atomicops_internals_mac.h" |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 146 | #elif defined(__native_client__) |
| 147 | #include "src/base/atomicops_internals_portable.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 148 | #elif defined(__GNUC__) && V8_HOST_ARCH_ARM64 |
| 149 | #include "src/base/atomicops_internals_arm64_gcc.h" |
| 150 | #elif defined(__GNUC__) && V8_HOST_ARCH_ARM |
| 151 | #include "src/base/atomicops_internals_arm_gcc.h" |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 152 | #elif defined(__GNUC__) && V8_HOST_ARCH_PPC |
| 153 | #include "src/base/atomicops_internals_ppc_gcc.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 154 | #elif defined(__GNUC__) && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64) |
| 155 | #include "src/base/atomicops_internals_x86_gcc.h" |
| 156 | #elif defined(__GNUC__) && V8_HOST_ARCH_MIPS |
| 157 | #include "src/base/atomicops_internals_mips_gcc.h" |
| 158 | #elif defined(__GNUC__) && V8_HOST_ARCH_MIPS64 |
| 159 | #include "src/base/atomicops_internals_mips64_gcc.h" |
Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame] | 160 | #elif defined(__GNUC__) && V8_HOST_ARCH_S390 |
| 161 | #include "src/base/atomicops_internals_s390_gcc.h" |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 162 | #else |
| 163 | #error "Atomic operations are not supported on your platform" |
| 164 | #endif |
| 165 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 166 | // On some platforms we need additional declarations to make |
| 167 | // AtomicWord compatible with our other Atomic* types. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 168 | #if defined(__APPLE__) || defined(__OpenBSD__) || defined(V8_OS_AIX) |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 169 | #include "src/base/atomicops_internals_atomicword_compat.h" |
| 170 | #endif |
| 171 | |
| 172 | #endif // V8_BASE_ATOMICOPS_H_ |