Merge branch 'wip/tsan/wsdeque' into wip/tsan/all

1 files changed, 15 insertions, 0 deletions

diff --git a/includes/stg/SMP.h b/includes/stg/SMP.h
index 8eff276e60..389dd95c88 100644
--- a/includes/stg/SMP.h
+++ b/includes/stg/SMP.h
@@ -454,6 +454,14 @@ load_load_barrier(void) {
 // Non-atomic addition for "approximate" counters that can be lossy
 #define NONATOMIC_ADD(ptr,val) RELAXED_STORE(ptr, RELAXED_LOAD(ptr) + val)
 
+// Explicit fences
+//
+// These are typically necessary only in very specific cases (e.g. WSDeque)
+// where the ordered operations aren't expressive enough to capture the desired
+// ordering.
+#define RELEASE_FENCE() __atomic_thread_fence(__ATOMIC_RELEASE)
+#define SEQ_CST_FENCE() __atomic_thread_fence(__ATOMIC_SEQ_CST)
+
 /* ---------------------------------------------------------------------- */
 #else /* !THREADED_RTS */
 
@@ -481,6 +489,10 @@ EXTERN_INLINE void load_load_barrier () {} /* nothing */
 // Non-atomic addition for "approximate" counters that can be lossy
 #define NONATOMIC_ADD(ptr,val) *ptr += val
 
+// Fences
+#define RELEASE_FENCE()
+#define SEQ_CST_FENCE()
+
 #if !IN_STG_CODE || IN_STGCRUN
 INLINE_HEADER StgWord
 xchg(StgPtr p, StgWord w)
@@ -529,6 +541,9 @@ atomic_dec(StgVolatilePtr p)
 }
 #endif
 
+/* An alias for the C11 declspec */
+#define ATOMIC
+
 #define VOLATILE_LOAD(p) ((StgWord)*((StgWord*)(p)))
 
 #endif /* !THREADED_RTS */