src/hotspot/share/gc/shenandoah/shenandoahFullGC.cpp

*** 242,19 ***
--- 242,23 ---
    {
      // The rest of code performs region moves, where region status is undefined
      // until all phases run together.
      ShenandoahHeapLocker lock(heap->lock());
  
+     FullGCForwarding::begin();
+ 
      phase2_calculate_target_addresses(worker_slices);
  
      OrderAccess::fence();
  
      phase3_update_references();
  
      phase4_compact_objects(worker_slices);
  
      phase5_epilog();
+ 
+     FullGCForwarding::end();
    }
  
    // Resize metaspace
    MetaspaceGC::compute_new_size();
  

*** 348,11 ***
    void do_object(oop p) {
      assert(_from_region != nullptr, "must set before work");
      assert(_heap->gc_generation()->complete_marking_context()->is_marked(p), "must be marked");
      assert(!_heap->gc_generation()->complete_marking_context()->allocated_after_mark_start(p), "must be truly marked");
  
!     size_t obj_size = p->size();
      if (_compact_point + obj_size > _to_region->end()) {
        finish();
  
        // Object doesn't fit. Pick next empty region and start compacting there.
        ShenandoahHeapRegion* new_to_region;
--- 352,13 ---
    void do_object(oop p) {
      assert(_from_region != nullptr, "must set before work");
      assert(_heap->gc_generation()->complete_marking_context()->is_marked(p), "must be marked");
      assert(!_heap->gc_generation()->complete_marking_context()->allocated_after_mark_start(p), "must be truly marked");
  
!     size_t old_size = p->size();
+     size_t new_size = p->copy_size(old_size, p->mark());
+     size_t obj_size = _compact_point == cast_from_oop<HeapWord*>(p) ? old_size : new_size;
      if (_compact_point + obj_size > _to_region->end()) {
        finish();
  
        // Object doesn't fit. Pick next empty region and start compacting there.
        ShenandoahHeapRegion* new_to_region;

*** 366,10 ***
--- 372,11 ---
  
        assert(new_to_region != _to_region, "must not reuse same to-region");
        assert(new_to_region != nullptr, "must not be null");
        _to_region = new_to_region;
        _compact_point = _to_region->bottom();
+       obj_size = _compact_point == cast_from_oop<HeapWord*>(p) ? old_size : new_size;
      }
  
      // Object fits into current region, record new location, if object does not move:
      assert(_compact_point + obj_size <= _to_region->end(), "must fit");
      shenandoah_assert_not_forwarded(nullptr, p);

*** 885,10 ***
--- 892,11 ---
        Copy::aligned_conjoint_words(compact_from, compact_to, size);
        oop new_obj = cast_to_oop(compact_to);
  
        ContinuationGCSupport::relativize_stack_chunk(new_obj);
        new_obj->init_mark();
+       new_obj->initialize_hash_if_necessary(p);
      }
    }
  };
  
  class ShenandoahCompactObjectsTask : public WorkerTask {