3 files changed, 27 insertions, 18 deletions

diff --git a/includes/rts/storage/ClosureMacros.h b/includes/rts/storage/ClosureMacros.h
index 0e956c4fa3..5674322bd2 100644
--- a/includes/rts/storage/ClosureMacros.h
+++ b/includes/rts/storage/ClosureMacros.h
@@ -46,10 +46,13 @@
    -------------------------------------------------------------------------- */
 
 INLINE_HEADER void SET_INFO(StgClosure *c, const StgInfoTable *info) {
-    c->header.info = info;
+    RELAXED_STORE(&c->header.info, info);
+}
+INLINE_HEADER void SET_INFO_RELEASE(StgClosure *c, const StgInfoTable *info) {
+    RELEASE_STORE(&c->header.info, info);
 }
 INLINE_HEADER const StgInfoTable *GET_INFO(StgClosure *c) {
-    return c->header.info;
+    return RELAXED_LOAD(&c->header.info);
 }
 
 #if defined(TABLES_NEXT_TO_CODE)
@@ -81,28 +84,28 @@ INLINE_HEADER StgConInfoTable *itbl_to_con_itbl(const StgInfoTable *i) {return (
 EXTERN_INLINE const StgInfoTable *get_itbl(const StgClosure *c);
 EXTERN_INLINE const StgInfoTable *get_itbl(const StgClosure *c)
 {
-   return INFO_PTR_TO_STRUCT(c->header.info);
+    return INFO_PTR_TO_STRUCT(RELAXED_LOAD(&c->header.info));
 }
 
 EXTERN_INLINE const StgRetInfoTable *get_ret_itbl(const StgClosure *c);
 EXTERN_INLINE const StgRetInfoTable *get_ret_itbl(const StgClosure *c)
 {
-   return RET_INFO_PTR_TO_STRUCT(c->header.info);
+    return RET_INFO_PTR_TO_STRUCT(RELAXED_LOAD(&c->header.info));
 }
 
 INLINE_HEADER const StgFunInfoTable *get_fun_itbl(const StgClosure *c)
 {
-   return FUN_INFO_PTR_TO_STRUCT(c->header.info);
+    return FUN_INFO_PTR_TO_STRUCT(RELAXED_LOAD(&c->header.info));
 }
 
 INLINE_HEADER const StgThunkInfoTable *get_thunk_itbl(const StgClosure *c)
 {
-   return THUNK_INFO_PTR_TO_STRUCT(c->header.info);
+    return THUNK_INFO_PTR_TO_STRUCT(RELAXED_LOAD(&c->header.info));
 }
 
 INLINE_HEADER const StgConInfoTable *get_con_itbl(const StgClosure *c)
 {
-   return CON_INFO_PTR_TO_STRUCT((c)->header.info);
+    return CON_INFO_PTR_TO_STRUCT(RELAXED_LOAD(&c->header.info));
 }
 
 INLINE_HEADER StgHalfWord GET_TAG(const StgClosure *con)
@@ -137,13 +140,19 @@ INLINE_HEADER StgHalfWord GET_TAG(const StgClosure *con)
 
 #define SET_HDR(c,_info,ccs)                            \
    {                                                    \
-        (c)->header.info = _info;                       \
         SET_PROF_HDR((StgClosure *)(c),ccs);            \
+        RELAXED_STORE(&(c)->header.info, _info);        \
+   }
+
+#define SET_HDR_RELEASE(c,_info,ccs)                    \
+   {                                                    \
+        SET_PROF_HDR((StgClosure *)(c),ccs);            \
+        RELEASE_STORE(&(c)->header.info, _info);        \
    }
 
 #define SET_ARR_HDR(c,info,costCentreStack,n_bytes)     \
-   SET_HDR(c,info,costCentreStack);                     \
-   (c)->bytes = n_bytes;
+   (c)->bytes = n_bytes;                                \
+   SET_HDR(c,info,costCentreStack);
 
 // Use when changing a closure from one kind to another
 #define OVERWRITE_INFO(c, new_info)                             \
@@ -251,8 +260,8 @@ INLINE_HEADER bool LOOKS_LIKE_INFO_PTR (StgWord p)
 
 INLINE_HEADER bool LOOKS_LIKE_CLOSURE_PTR (const void *p)
 {
-    return LOOKS_LIKE_INFO_PTR((StgWord)
-            (UNTAG_CONST_CLOSURE((const StgClosure *)(p)))->header.info);
+    const StgInfoTable *info = RELAXED_LOAD(&UNTAG_CONST_CLOSURE((const StgClosure *) (p))->header.info);
+    return LOOKS_LIKE_INFO_PTR((StgWord) info);
 }
 
 /* -----------------------------------------------------------------------------
diff --git a/includes/rts/storage/Closures.h b/includes/rts/storage/Closures.h
index 3196efd3de..981e162ec1 100644
--- a/includes/rts/storage/Closures.h
+++ b/includes/rts/storage/Closures.h
@@ -340,9 +340,9 @@ typedef struct StgTVarWatchQueue_ {
 
 typedef struct {
   StgHeader                  header;
-  StgClosure                *volatile current_value;
-  StgTVarWatchQueue         *volatile first_watch_queue_entry;
-  StgInt                     volatile num_updates;
+  StgClosure                *current_value; /* accessed via atomics */
+  StgTVarWatchQueue         *first_watch_queue_entry; /* accessed via atomics */
+  StgInt                     num_updates; /* accessed via atomics */
 } StgTVar;
 
 /* new_value == expected_value for read-only accesses */
diff --git a/includes/rts/storage/GC.h b/includes/rts/storage/GC.h
index 9f4a0dde07..e8dc05048a 100644
--- a/includes/rts/storage/GC.h
+++ b/includes/rts/storage/GC.h
@@ -247,9 +247,9 @@ extern bool keepCAFs;
 
 INLINE_HEADER void initBdescr(bdescr *bd, generation *gen, generation *dest)
 {
-    bd->gen     = gen;
-    bd->gen_no  = gen->no;
-    bd->dest_no = dest->no;
+    RELAXED_STORE(&bd->gen, gen);
+    RELAXED_STORE(&bd->gen_no, gen->no);
+    RELAXED_STORE(&bd->dest_no, dest->no);
 
 #if !IN_STG_CODE
     /* See Note [RtsFlags is a pointer in STG code] */