--- a/hotspot/src/share/vm/gc_implementation/parNew/parOopClosures.inline.hpp	Fri Apr 11 09:56:35 2008 -0400
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parOopClosures.inline.hpp	Sun Apr 13 17:43:42 2008 -0400
@@ -22,10 +22,9 @@
  *
  */
 
-inline void ParScanWeakRefClosure::do_oop(oop* p)
-{
-  oop obj = *p;
-  assert (obj != NULL, "null weak reference?");
+template <class T> inline void ParScanWeakRefClosure::do_oop_work(T* p) {
+  assert (!oopDesc::is_null(*p), "null weak reference?");
+  oop obj = oopDesc::load_decode_heap_oop_not_null(p);
   // weak references are sometimes scanned twice; must check
   // that to-space doesn't already contain this object
   if ((HeapWord*)obj < _boundary && !_g->to()->is_in_reserved(obj)) {
@@ -33,41 +32,43 @@
     // ParScanClosure::do_oop_work).
     klassOop objK = obj->klass();
     markOop m = obj->mark();
+    oop new_obj;
     if (m->is_marked()) { // Contains forwarding pointer.
-      *p = ParNewGeneration::real_forwardee(obj);
+      new_obj = ParNewGeneration::real_forwardee(obj);
     } else {
       size_t obj_sz = obj->size_given_klass(objK->klass_part());
-      *p = ((ParNewGeneration*)_g)->copy_to_survivor_space(_par_scan_state,
-                                                           obj, obj_sz, m);
+      new_obj = ((ParNewGeneration*)_g)->copy_to_survivor_space(_par_scan_state,
+                                                                obj, obj_sz, m);
     }
+    oopDesc::encode_store_heap_oop_not_null(p, new_obj);
   }
 }
 
-inline void ParScanWeakRefClosure::do_oop_nv(oop* p)
-{
-  ParScanWeakRefClosure::do_oop(p);
-}
+inline void ParScanWeakRefClosure::do_oop_nv(oop* p)       { ParScanWeakRefClosure::do_oop_work(p); }
+inline void ParScanWeakRefClosure::do_oop_nv(narrowOop* p) { ParScanWeakRefClosure::do_oop_work(p); }
 
-inline void ParScanClosure::par_do_barrier(oop* p) {
+template <class T> inline void ParScanClosure::par_do_barrier(T* p) {
   assert(generation()->is_in_reserved(p), "expected ref in generation");
-  oop obj = *p;
-  assert(obj != NULL, "expected non-null object");
+  assert(!oopDesc::is_null(*p), "expected non-null object");
+  oop obj = oopDesc::load_decode_heap_oop_not_null(p);
   // If p points to a younger generation, mark the card.
   if ((HeapWord*)obj < gen_boundary()) {
     rs()->write_ref_field_gc_par(p, obj);
   }
 }
 
-inline void ParScanClosure::do_oop_work(oop* p,
+template <class T>
+inline void ParScanClosure::do_oop_work(T* p,
                                         bool gc_barrier,
                                         bool root_scan) {
-  oop obj = *p;
   assert((!Universe::heap()->is_in_reserved(p) ||
           generation()->is_in_reserved(p))
          && (generation()->level() == 0 || gc_barrier),
          "The gen must be right, and we must be doing the barrier "
          "in older generations.");
-  if (obj != NULL) {
+  T heap_oop = oopDesc::load_heap_oop(p);
+  if (!oopDesc::is_null(heap_oop)) {
+    oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
     if ((HeapWord*)obj < _boundary) {
       assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?");
       // OK, we need to ensure that it is copied.
@@ -78,11 +79,14 @@
       // forwarded.
       klassOop objK = obj->klass();
       markOop m = obj->mark();
+      oop new_obj;
       if (m->is_marked()) { // Contains forwarding pointer.
-        *p = ParNewGeneration::real_forwardee(obj);
+        new_obj = ParNewGeneration::real_forwardee(obj);
+        oopDesc::encode_store_heap_oop_not_null(p, new_obj);
       } else {
         size_t obj_sz = obj->size_given_klass(objK->klass_part());
-        *p = _g->copy_to_survivor_space(_par_scan_state, obj, obj_sz, m);
+        new_obj = _g->copy_to_survivor_space(_par_scan_state, obj, obj_sz, m);
+        oopDesc::encode_store_heap_oop_not_null(p, new_obj);
         if (root_scan) {
           // This may have pushed an object.  If we have a root
           // category with a lot of roots, can't let the queue get too
@@ -97,3 +101,9 @@
     }
   }
 }
+
+inline void ParScanWithBarrierClosure::do_oop_nv(oop* p)       { ParScanClosure::do_oop_work(p, true, false); }
+inline void ParScanWithBarrierClosure::do_oop_nv(narrowOop* p) { ParScanClosure::do_oop_work(p, true, false); }
+
+inline void ParScanWithoutBarrierClosure::do_oop_nv(oop* p)       { ParScanClosure::do_oop_work(p, false, false); }
+inline void ParScanWithoutBarrierClosure::do_oop_nv(narrowOop* p) { ParScanClosure::do_oop_work(p, false, false); }