src/hotspot/share/oops/valueArrayKlass.cpp

@@ -182,10 +182,16 @@
 
 oop ValueArrayKlass::protection_domain() const {
   return element_klass()->protection_domain();
 }
 
+// Temp hack having this here: need to move towards Access API
+static bool needs_backwards_copy(arrayOop s, int src_pos,
+                                 arrayOop d, int dst_pos, int length) {
+  return oopDesc::equals(s, d) && (dst_pos > src_pos) && (dst_pos - src_pos) < length;
+}
+
 void ValueArrayKlass::copy_array(arrayOop s, int src_pos,
                                  arrayOop d, int dst_pos, int length, TRAPS) {
 
   assert(s->is_objArray() || s->is_valueArray(), "must be obj or value array");
 

@@ -234,15 +240,26 @@
        address dst = (address) da->value_at_addr(dst_pos, layout_helper());
        address src = (address) sa->value_at_addr(src_pos, layout_helper());
        if (contains_oops()) {
          int elem_incr = 1 << log2_element_size();
          address src_end = src + (length << log2_element_size());
+         if (needs_backwards_copy(s, src_pos, d, dst_pos, length)) {
+           swap(src, src_end);
+           dst = dst + (length << log2_element_size());
+           do {
+             src -= elem_incr;
+             dst -= elem_incr;
+             s_elem_vklass->value_store(src, dst, element_byte_size(), true, false);
+           } while (src > src_end);
+         } else {
+           address src_end = src + (length << log2_element_size());
          while (src < src_end) {
            s_elem_vklass->value_store(src, dst, element_byte_size(), true, false);
            src += elem_incr;
            dst += elem_incr;
          }
+         }
        } else {
          // we are basically a type array...don't bother limiting element copy
          // it would have to be a lot wasted space to be worth value_store() calls, need a setting here ?
          Copy::conjoint_memory_atomic(src, dst, (size_t)length << log2_element_size());
        }