mono/utils/mono-membar.h

   1 /*
   2  * mono-membar.h: Memory barrier inline functions
   3  *
   4  * Author:
   5  *      Mark Probst (mark.probst@gmail.com)
   6  *
   7  * (C) 2007 Novell, Inc
   8  */
   9
  10 #ifndef _MONO_UTILS_MONO_MEMBAR_H_
  11 #define _MONO_UTILS_MONO_MEMBAR_H_
  12
  13 #include <config.h>
  14
  15 #include <glib.h>
  16
  17 #ifdef _MSC_VER
  18 #ifndef WIN32_LEAN_AND_MEAN
  19 #define WIN32_LEAN_AND_MEAN
  20 #endif
  21 #include <windows.h>
  22 #include <intrin.h>
  23
  24 static inline void mono_memory_barrier (void)
  25 {
  26         /* NOTE: _ReadWriteBarrier and friends only prevent the
  27            compiler from reordering loads and stores. To prevent
  28            the CPU from doing the same, we have to use the
  29            MemoryBarrier macro which expands to e.g. a serializing
  30            XCHG instruction on x86. Also note that the MemoryBarrier
  31            macro does *not* imply _ReadWriteBarrier, so that call
  32            cannot be eliminated. */
  33         _ReadWriteBarrier ();
  34         MemoryBarrier ();
  35 }
  36
  37 static inline void mono_memory_read_barrier (void)
  38 {
  39         _ReadBarrier ();
  40         MemoryBarrier ();
  41 }
  42
  43 static inline void mono_memory_write_barrier (void)
  44 {
  45         _WriteBarrier ();
  46         MemoryBarrier ();
  47 }
  48 #elif defined(USE_GCC_ATOMIC_OPS)
  49 static inline void mono_memory_barrier (void)
  50 {
  51         __sync_synchronize ();
  52 }
  53
  54 static inline void mono_memory_read_barrier (void)
  55 {
  56         mono_memory_barrier ();
  57 }
  58
  59 static inline void mono_memory_write_barrier (void)
  60 {
  61         mono_memory_barrier ();
  62 }
  63 #else
  64 #error "Don't know how to do memory barriers!"
  65 #endif
  66
  67 #endif  /* _MONO_UTILS_MONO_MEMBAR_H_ */