[project @ 2002-04-19 10:25:00 by simonmar]

- traverse_weak_ptr_list(): Deal with EVACUATED objects on the weak
  pointer list.

- mark_weak_ptr_list(): add an assertion.

diff --git a/ghc/rts/GC.c b/ghc/rts/GC.c
index 8dbe589..563392c 100644 (file)
--- a/ghc/rts/GC.c
+++ b/ghc/rts/GC.c
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: GC.c,v 1.133 2002/04/13 05:16:25 sof Exp $
+ * $Id: GC.c,v 1.134 2002/04/19 10:25:00 simonmar Exp $
  *
  * (c) The GHC Team 1998-1999
  *
@@ -1104,31 +1104,41 @@ traverse_weak_ptr_list(void)
              continue;
          }
          
-         ASSERT(get_itbl(w)->type == WEAK);
-         
-         /* Now, check whether the key is reachable.
-          */
-         new = isAlive(w->key);
-         if (new != NULL) {
-             w->key = new;
-             // evacuate the value and finalizer 
-             w->value = evacuate(w->value);
-             w->finalizer = evacuate(w->finalizer);
-             // remove this weak ptr from the old_weak_ptr list 
-             *last_w = w->link;
-             // and put it on the new weak ptr list 
-             next_w  = w->link;
-             w->link = weak_ptr_list;
-             weak_ptr_list = w;
-             flag = rtsTrue;
-             IF_DEBUG(weak, belch("Weak pointer still alive at %p -> %p", 
-                                  w, w->key));
-             continue;
-         }
-         else {
-             last_w = &(w->link);
-             next_w = w->link;
+         switch (get_itbl(w)->type) {
+
+         case EVACUATED:
+             next_w = (StgWeak *)((StgEvacuated *)w)->evacuee;
+             *last_w = next_w;
              continue;
+
+         case WEAK:
+             /* Now, check whether the key is reachable.
+              */
+             new = isAlive(w->key);
+             if (new != NULL) {
+                 w->key = new;
+                 // evacuate the value and finalizer 
+                 w->value = evacuate(w->value);
+                 w->finalizer = evacuate(w->finalizer);
+                 // remove this weak ptr from the old_weak_ptr list 
+                 *last_w = w->link;
+                 // and put it on the new weak ptr list 
+                 next_w  = w->link;
+                 w->link = weak_ptr_list;
+                 weak_ptr_list = w;
+                 flag = rtsTrue;
+                 IF_DEBUG(weak, belch("Weak pointer still alive at %p -> %p", 
+                                      w, w->key));
+                 continue;
+             }
+             else {
+                 last_w = &(w->link);
+                 next_w = w->link;
+                 continue;
+             }
+
+         default:
+             barf("traverse_weak_ptr_list: not WEAK");
          }
       }
       
@@ -1241,6 +1251,9 @@ mark_weak_ptr_list ( StgWeak **list )
 
   last_w = list;
   for (w = *list; w; w = w->link) {
+      // w might be WEAK, EVACUATED, or DEAD_WEAK (actually CON_STATIC) here
+      ASSERT(w->header.info == &stg_DEAD_WEAK_info 
+            || get_itbl(w)->type == WEAK || get_itbl(w)->type == EVACUATED);
       (StgClosure *)w = evacuate((StgClosure *)w);
       *last_w = w;
       last_w = &(w->link);