50 

    51 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,

    52                                  HeapRegion* hr,

    53                                  G1ParPushHeapRSClosure* cl,

    54                                  CardTableModRefBS::PrecisionStyle precision) :

    55   DirtyCardToOopClosure(hr, cl, precision, NULL),

    56   _hr(hr), _rs_scan(cl), _g1(g1) { }

    57 

    58 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,

    59                                       HeapWord* bottom,

    60                                       HeapWord* top) {

    61   G1CollectedHeap* g1h = _g1;

    62   size_t oop_size;

    63   HeapWord* cur = bottom;

    64 

    65   // Start filtering what we add to the remembered set. If the object is

    66   // not considered dead, either because it is marked (in the mark bitmap)

    67   // or it was allocated after marking finished, then we add it. Otherwise

    68   // we can safely ignore the object.

    69   if (!g1h->is_obj_dead(oop(cur))) {

    70     oop_size = oop(cur)->oop_iterate_size(_rs_scan, mr);

    71   } else {

    72     oop_size = _hr->block_size(cur);

    73   }

    74 

    75   cur += oop_size;

    76 

    77   if (cur < top) {

    78     oop cur_oop = oop(cur);

    79     oop_size = _hr->block_size(cur);

    80     HeapWord* next_obj = cur + oop_size;

    81     while (next_obj < top) {

    82       // Keep filtering the remembered set.

    83       if (!g1h->is_obj_dead(cur_oop)) {

    84         // Bottom lies entirely below top, so we can call the

    85         // non-memRegion version of oop_iterate below.

    86         cur_oop->oop_iterate(_rs_scan);

    87       }

    88       cur = next_obj;

    89       cur_oop = oop(cur);

    90       oop_size = _hr->block_size(cur);

    91       next_obj = cur + oop_size;

    92     }

    93 

    94     // Last object. Need to do dead-obj filtering here too.

    95     if (!g1h->is_obj_dead(oop(cur))) {

    96       oop(cur)->oop_iterate(_rs_scan, mr);

    97     }

    98   }

    99 }