Eliminate data race FP reported in need_unreachable_finalization by TSan

* finalize.c (need_unreachable_finalization): Move definition upper to
be before GC_register_finalizer_inner; add TODO item.
* finalize.c (GC_register_finalizer_inner): Set
need_unreachable_finalization to true (after LOCK) if mp points to
GC_unreachable_finalize_mark_proc.
* finalize.c (GC_register_finalizer_unreachable): Do not set
need_unreachable_finalization.

1 files changed, 6 insertions, 4 deletions

diff --git a/finalize.c b/finalize.c
index 62ec894c..10c6ffb5 100644
--- a/finalize.c
+++ b/finalize.c
@@ -660,6 +660,10 @@ STATIC void GC_unreachable_finalize_mark_proc(ptr_t p)
     GC_normal_finalize_mark_proc(p);
 }
 
+static GC_bool need_unreachable_finalization = FALSE;
+        /* Avoid the work if this is not used.  */
+        /* TODO: turn need_unreachable_finalization into a counter */
+
 /* Register a finalization function.  See gc.h for details.     */
 /* The last parameter is a procedure that determines            */
 /* marking for finalization ordering.  Any objects marked       */
@@ -682,6 +686,8 @@ STATIC void GC_register_finalizer_inner(void * obj,
     }
     LOCK();
     GC_ASSERT(obj != NULL && GC_base_C(obj) == obj);
+    if (mp == GC_unreachable_finalize_mark_proc)
+        need_unreachable_finalization = TRUE;
     if (EXPECT(NULL == GC_fnlz_roots.fo_head, FALSE)
         || EXPECT(GC_fo_entries > ((word)1 << GC_log_fo_table_size), FALSE)) {
         GC_grow_table((struct hash_chain_entry ***)&GC_fnlz_roots.fo_head,
@@ -823,14 +829,10 @@ GC_API void GC_CALL GC_register_finalizer_no_order(void * obj,
                                 ocd, GC_null_finalize_mark_proc);
 }
 
-static GC_bool need_unreachable_finalization = FALSE;
-        /* Avoid the work if this isn't used.   */
-
 GC_API void GC_CALL GC_register_finalizer_unreachable(void * obj,
                                GC_finalization_proc fn, void * cd,
                                GC_finalization_proc *ofn, void ** ocd)
 {
-    need_unreachable_finalization = TRUE;
     GC_ASSERT(GC_java_finalization);
     GC_register_finalizer_inner(obj, fn, cd, ofn,
                                 ocd, GC_unreachable_finalize_mark_proc);