Merge pull request #755 from ondrejmyska/master

[mono.git] / mono / utils / mono-membar.h

diff --git a/mono/utils/mono-membar.h b/mono/utils/mono-membar.h
index 878c1c6306d9a692f52cdad1b30a4cc4e64185cc..fa4057a0eeed6a1afc2ea855def535e33a1424ac 100644 (file)
--- a/mono/utils/mono-membar.h
+++ b/mono/utils/mono-membar.h
@@ -14,45 +14,54 @@
 
 #include <glib.h>
 
-#if defined(__x86_64__) || defined(TARGET_AMD64)
-#ifndef _MSC_VER
-static inline void mono_memory_barrier (void)
-{
-       __asm__ __volatile__ ("mfence" : : : "memory");
-}
-
-static inline void mono_memory_read_barrier (void)
-{
-       __asm__ __volatile__ ("lfence" : : : "memory");
-}
-
-static inline void mono_memory_write_barrier (void)
-{
-       __asm__ __volatile__ ("sfence" : : : "memory");
-}
-#else
+#ifdef _MSC_VER
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h>
 #include <intrin.h>
 
 static inline void mono_memory_barrier (void)
 {
+       /* NOTE: _ReadWriteBarrier and friends only prevent the
+          compiler from reordering loads and stores. To prevent
+          the CPU from doing the same, we have to use the
+          MemoryBarrier macro which expands to e.g. a serializing
+          XCHG instruction on x86. Also note that the MemoryBarrier
+          macro does *not* imply _ReadWriteBarrier, so that call
+          cannot be eliminated. */
        _ReadWriteBarrier ();
+       MemoryBarrier ();
 }
 
 static inline void mono_memory_read_barrier (void)
 {
        _ReadBarrier ();
+       MemoryBarrier ();
 }
 
 static inline void mono_memory_write_barrier (void)
 {
        _WriteBarrier ();
+       MemoryBarrier ();
 }
-#endif
-#elif defined(__i386__) || defined(TARGET_X86)
-#ifndef _MSC_VER
+#elif defined(__WIN32__) || defined(_WIN32)
+#include <windows.h>
+
+/* Since we only support GCC 3.x in Cygwin for
+   some arcane reason, we have to use inline
+   assembly to get fences (__sync_synchronize
+   is not available). */
+
 static inline void mono_memory_barrier (void)
 {
-       __asm__ __volatile__ ("lock; addl $0,0(%%esp)" : : : "memory");
+       __asm__ __volatile__ (
+               "lock\n\t"
+               "addl\t$0,0(%%esp)\n\t"
+               :
+               :
+               : "memory"
+       );
 }
 
 static inline void mono_memory_read_barrier (void)
@@ -64,24 +73,21 @@ static inline void mono_memory_write_barrier (void)
 {
        mono_memory_barrier ();
 }
-#else
-#include <intrin.h>
-
+#elif defined(USE_GCC_ATOMIC_OPS)
 static inline void mono_memory_barrier (void)
 {
-       _ReadWriteBarrier ();
+       __sync_synchronize ();
 }
 
 static inline void mono_memory_read_barrier (void)
 {
-       _ReadBarrier ();
+       mono_memory_barrier ();
 }
 
 static inline void mono_memory_write_barrier (void)
 {
-       _WriteBarrier ();
+       mono_memory_barrier ();
 }
-#endif
 #elif defined(sparc) || defined(__sparc__)
 static inline void mono_memory_barrier (void)
 {
@@ -108,44 +114,6 @@ static inline void mono_memory_read_barrier (void)
        mono_memory_barrier ();
 }
 
-static inline void mono_memory_write_barrier (void)
-{
-       mono_memory_barrier ();
-}
-#elif defined(__ppc__) || defined(__powerpc__) || defined(__ppc64__)
-static inline void mono_memory_barrier (void)
-{
-       __asm__ __volatile__ ("sync" : : : "memory");
-}
-
-static inline void mono_memory_read_barrier (void)
-{
-       mono_memory_barrier ();
-}
-
-static inline void mono_memory_write_barrier (void)
-{
-       __asm__ __volatile__ ("eieio" : : : "memory");
-}
-
-#elif defined(__arm__)
-static inline void mono_memory_barrier (void)
-{
-#if defined(__native_client__) || defined(HAVE_ARMV7)
-       /* NaCl requires ARMv7 CPUs. */
-       __asm__ __volatile__("dsb" : : : "memory");
-#elif defined(HAVE_ARMV6)
-       __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" : : "r" (0) : "memory");
-#else
-       /* No barrier required on pre-v6. */
-#endif
-}
-
-static inline void mono_memory_read_barrier (void)
-{
-       mono_memory_barrier ();
-}
-
 static inline void mono_memory_write_barrier (void)
 {
        mono_memory_barrier ();
@@ -165,21 +133,6 @@ static inline void mono_memory_write_barrier (void)
 {
        mono_memory_barrier ();
 }
-#elif defined(__mips__)
-static inline void mono_memory_barrier (void)
-{
-        __asm__ __volatile__ ("" : : : "memory");
-}
-
-static inline void mono_memory_read_barrier (void)
-{
-        mono_memory_barrier ();
-}
-
-static inline void mono_memory_write_barrier (void)
-{
-        mono_memory_barrier ();
-}
 #elif defined(MONO_CROSS_COMPILE)
 static inline void mono_memory_barrier (void)
 {
@@ -192,6 +145,8 @@ static inline void mono_memory_read_barrier (void)
 static inline void mono_memory_write_barrier (void)
 {
 }
+#else
+#error "Don't know how to do memory barriers!"
 #endif
 
 #endif /* _MONO_UTILS_MONO_MEMBAR_H_ */