| … | |
… | |
| 137 | #endif |
137 | #endif |
| 138 | #endif |
138 | #endif |
| 139 | |
139 | |
| 140 | #ifndef ECB_MEMORY_FENCE |
140 | #ifndef ECB_MEMORY_FENCE |
| 141 | #if ECB_GCC_VERSION(4,7) |
141 | #if ECB_GCC_VERSION(4,7) |
| 142 | /* see comment below about the C11 memory model. in short - avoid */ |
142 | /* see comment below (stdatomic.h) about the C11 memory model. */ |
| 143 | #define ECB_MEMORY_FENCE __atomic_thread_fence (__ATOMIC_SEQ_CST) |
143 | #define ECB_MEMORY_FENCE __atomic_thread_fence (__ATOMIC_SEQ_CST) |
| 144 | #elif defined __clang && __has_feature (cxx_atomic) |
144 | #elif defined __clang && __has_feature (cxx_atomic) |
| 145 | /* see above */ |
145 | /* see comment below (stdatomic.h) about the C11 memory model. */ |
| 146 | #define ECB_MEMORY_FENCE __c11_atomic_thread_fence (__ATOMIC_SEQ_CST) |
146 | #define ECB_MEMORY_FENCE __c11_atomic_thread_fence (__ATOMIC_SEQ_CST) |
| 147 | #elif ECB_GCC_VERSION(4,4) || defined __INTEL_COMPILER || defined __clang__ |
147 | #elif ECB_GCC_VERSION(4,4) || defined __INTEL_COMPILER || defined __clang__ |
| 148 | #define ECB_MEMORY_FENCE __sync_synchronize () |
148 | #define ECB_MEMORY_FENCE __sync_synchronize () |
| 149 | #elif _MSC_VER >= 1400 /* VC++ 2005 */ |
149 | #elif _MSC_VER >= 1400 /* VC++ 2005 */ |
| 150 | #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier) |
150 | #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier) |
| … | |
… | |
| 167 | #ifndef ECB_MEMORY_FENCE |
167 | #ifndef ECB_MEMORY_FENCE |
| 168 | #if ECB_C11 && !defined __STDC_NO_ATOMICS__ |
168 | #if ECB_C11 && !defined __STDC_NO_ATOMICS__ |
| 169 | /* we assume that these memory fences work on all variables/all memory accesses, */ |
169 | /* we assume that these memory fences work on all variables/all memory accesses, */ |
| 170 | /* not just C11 atomics and atomic accesses */ |
170 | /* not just C11 atomics and atomic accesses */ |
| 171 | #include <stdatomic.h> |
171 | #include <stdatomic.h> |
| 172 | /* unfortunately, the C11 memory model seems to be very limited, and unable to express */ |
172 | /* Unfortunately, neither gcc 4.7 nor clang 3.1 generate any instructions for */ |
| 173 | /* simple barrier semantics. That means we need to take out thor's hammer. */ |
173 | /* any fence other than seq_cst, which isn't very efficient for us. */ |
|
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174 | /* Why that is, we don't know - either the C11 memory model is quite useless */ |
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175 | /* for most usages, or gcc and clang have a bug */ |
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176 | /* I *currently* lean towards the latter, and inefficiently implement */ |
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177 | /* all three of ecb's fences as a seq_cst fence */ |
| 174 | #define ECB_MEMORY_FENCE atomic_thread_fence (memory_order_seq_cst) |
178 | #define ECB_MEMORY_FENCE atomic_thread_fence (memory_order_seq_cst) |
| 175 | #endif |
179 | #endif |
| 176 | #endif |
180 | #endif |
| 177 | |
181 | |
| 178 | #ifndef ECB_MEMORY_FENCE |
182 | #ifndef ECB_MEMORY_FENCE |
