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

@@ -1202,11 +1202,17 @@
                                                 ShenandoahAffiliation target_gen) {
    assert(target_gen == YOUNG_GENERATION, "Only expect evacuations to young in this mode");
    assert(from_region->is_young(), "Only expect evacuations from young in this mode");
    bool alloc_from_lab = true;
    HeapWord* copy = nullptr;
-   size_t size = ShenandoahForwarding::size(p);
+ 
+   markWord mark = p->mark();
+   if (ShenandoahForwarding::is_forwarded(mark)) {
+     return ShenandoahForwarding::get_forwardee(p);
+   }
+   size_t old_size = ShenandoahForwarding::size(p);
+   size_t size = p->copy_size(old_size, mark);
  
  #ifdef ASSERT
    if (ShenandoahOOMDuringEvacALot &&
        (os::random() & 1) == 0) { // Simulate OOM every ~2nd slow-path call
      copy = nullptr;

@@ -1232,17 +1238,18 @@
  
      return ShenandoahBarrierSet::resolve_forwarded(p);
    }
  
    // Copy the object:
-   Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(p), copy, size);
+   Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(p), copy, old_size);
  
    // Try to install the new forwarding pointer.
    oop copy_val = cast_to_oop(copy);
    oop result = ShenandoahForwarding::try_update_forwardee(p, copy_val);
    if (result == copy_val) {
      // Successfully evacuated. Our copy is now the public one!
+     copy_val->initialize_hash_if_necessary(p);
      ContinuationGCSupport::relativize_stack_chunk(copy_val);
      shenandoah_assert_correct(nullptr, copy_val);
      return copy_val;
    }  else {
      // Failed to evacuate. We need to deal with the object that is left behind. Since this