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      1 #ifndef JEMALLOC_INTERNAL_ATOMIC_H
      2 #define JEMALLOC_INTERNAL_ATOMIC_H
      3 
      4 #define ATOMIC_INLINE static inline
      5 
      6 #if defined(JEMALLOC_GCC_ATOMIC_ATOMICS)
      7 #  include "jemalloc/internal/atomic_gcc_atomic.h"
      8 #elif defined(JEMALLOC_GCC_SYNC_ATOMICS)
      9 #  include "jemalloc/internal/atomic_gcc_sync.h"
     10 #elif defined(_MSC_VER)
     11 #  include "jemalloc/internal/atomic_msvc.h"
     12 #elif defined(JEMALLOC_C11_ATOMICS)
     13 #  include "jemalloc/internal/atomic_c11.h"
     14 #else
     15 #  error "Don't have atomics implemented on this platform."
     16 #endif
     17 
     18 /*
     19  * This header gives more or less a backport of C11 atomics. The user can write
     20  * JEMALLOC_GENERATE_ATOMICS(type, short_type, lg_sizeof_type); to generate
     21  * counterparts of the C11 atomic functions for type, as so:
     22  *   JEMALLOC_GENERATE_ATOMICS(int *, pi, 3);
     23  * and then write things like:
     24  *   int *some_ptr;
     25  *   atomic_pi_t atomic_ptr_to_int;
     26  *   atomic_store_pi(&atomic_ptr_to_int, some_ptr, ATOMIC_RELAXED);
     27  *   int *prev_value = atomic_exchange_pi(&ptr_to_int, NULL, ATOMIC_ACQ_REL);
     28  *   assert(some_ptr == prev_value);
     29  * and expect things to work in the obvious way.
     30  *
     31  * Also included (with naming differences to avoid conflicts with the standard
     32  * library):
     33  *   atomic_fence(atomic_memory_order_t) (mimics C11's atomic_thread_fence).
     34  *   ATOMIC_INIT (mimics C11's ATOMIC_VAR_INIT).
     35  */
     36 
     37 /*
     38  * Pure convenience, so that we don't have to type "atomic_memory_order_"
     39  * quite so often.
     40  */
     41 #define ATOMIC_RELAXED atomic_memory_order_relaxed
     42 #define ATOMIC_ACQUIRE atomic_memory_order_acquire
     43 #define ATOMIC_RELEASE atomic_memory_order_release
     44 #define ATOMIC_ACQ_REL atomic_memory_order_acq_rel
     45 #define ATOMIC_SEQ_CST atomic_memory_order_seq_cst
     46 
     47 /*
     48  * Not all platforms have 64-bit atomics.  If we do, this #define exposes that
     49  * fact.
     50  */
     51 #if (LG_SIZEOF_PTR == 3 || LG_SIZEOF_INT == 3)
     52 #  define JEMALLOC_ATOMIC_U64
     53 #endif
     54 
     55 JEMALLOC_GENERATE_ATOMICS(void *, p, LG_SIZEOF_PTR)
     56 
     57 /*
     58  * There's no actual guarantee that sizeof(bool) == 1, but it's true on the only
     59  * platform that actually needs to know the size, MSVC.
     60  */
     61 JEMALLOC_GENERATE_ATOMICS(bool, b, 0)
     62 
     63 JEMALLOC_GENERATE_INT_ATOMICS(unsigned, u, LG_SIZEOF_INT)
     64 
     65 JEMALLOC_GENERATE_INT_ATOMICS(size_t, zu, LG_SIZEOF_PTR)
     66 
     67 JEMALLOC_GENERATE_INT_ATOMICS(ssize_t, zd, LG_SIZEOF_PTR)
     68 
     69 JEMALLOC_GENERATE_INT_ATOMICS(uint32_t, u32, 2)
     70 
     71 #ifdef JEMALLOC_ATOMIC_U64
     72 JEMALLOC_GENERATE_INT_ATOMICS(uint64_t, u64, 3)
     73 #endif
     74 
     75 #undef ATOMIC_INLINE
     76 
     77 #endif /* JEMALLOC_INTERNAL_ATOMIC_H */
     78