353 }

   354 

   355 HeapWord*

   356 HeapRegion::object_iterate_mem_careful(MemRegion mr,

   357                                                  ObjectClosure* cl) {

   358   G1CollectedHeap* g1h = G1CollectedHeap::heap();

   359   // We used to use "block_start_careful" here.  But we're actually happy

   360   // to update the BOT while we do this...

   361   HeapWord* cur = block_start(mr.start());

   362   mr = mr.intersection(used_region());

   363   if (mr.is_empty()) return NULL;

   364   // Otherwise, find the obj that extends onto mr.start().

   365 

   366   assert(cur <= mr.start()

   367          && (oop(cur)->klass_or_null() == NULL ||

   368              cur + oop(cur)->size() > mr.start()),

   369          "postcondition of block_start");

   370   oop obj;

   371   while (cur < mr.end()) {

   372     obj = oop(cur);

   373     if (obj->klass_or_null() == NULL) {

   374       // Ran into an unparseable point.

   375       return cur;

   376     } else if (!g1h->is_obj_dead(obj)) {

   377       cl->do_object(obj);

   378     }

   379     cur += block_size(cur);

   380   }

   381   return NULL;