Assert that disappearing links are accessible during registration and GC

* finalize.c [GC_ASSERTIONS] (GC_register_disappearing_link_inner):
Pass *link to GC_noop1().
* finalize.c [!GC_MOVE_DISAPPEARING_LINK_NOT_NEEDED && GC_ASSERTIONS]
(GC_move_disappearing_link_inner): Pass *new_link to GC_noop1().
* finalize.c [GC_ASSERTIONS] (GC_make_disappearing_links_disappear):
Dereference revealed curr_dl->dl_hidden_link (and pass the value to
GC_noop1); add comment.

1 files changed, 10 insertions, 0 deletions

diff --git a/finalize.c b/finalize.c
index 8782cd21..9308959c 100644
--- a/finalize.c
+++ b/finalize.c
@@ -168,6 +168,9 @@ STATIC int GC_register_disappearing_link_inner(
     DCL_LOCK_STATE;
 
     if (EXPECT(GC_find_leak, FALSE)) return GC_UNIMPLEMENTED;
+#   ifdef GC_ASSERTIONS
+      GC_noop1((word)(*link)); /* check accessibility */
+#   endif
     LOCK();
     GC_ASSERT(obj != NULL && GC_base_C(obj) == obj);
     if (EXPECT(NULL == dl_hashtbl -> head, FALSE)
@@ -520,6 +523,9 @@ GC_API GC_await_finalize_proc GC_CALL GC_get_await_finalize_proc(void)
     size_t curr_index, new_index;
     word curr_hidden_link, new_hidden_link;
 
+#   ifdef GC_ASSERTIONS
+      GC_noop1((word)(*new_link));
+#   endif
     GC_ASSERT(I_HOLD_LOCK());
     if (EXPECT(NULL == dl_hashtbl -> head, FALSE)) return GC_NOT_FOUND;
 
@@ -931,6 +937,10 @@ GC_INLINE void GC_make_disappearing_links_disappear(
 
     for (curr_dl = dl_hashtbl->head[i]; curr_dl != NULL; curr_dl = next_dl) {
       next_dl = dl_next(curr_dl);
+#     ifdef GC_ASSERTIONS
+         /* Check accessibility of the location pointed by link. */
+        GC_noop1(*(word *)GC_REVEAL_POINTER(curr_dl->dl_hidden_link));
+#     endif
       if (is_remove_dangling) {
         ptr_t real_link = (ptr_t)GC_base(GC_REVEAL_POINTER(
                                                 curr_dl->dl_hidden_link));