--- /dev/null	2019-03-11 09:54:37.645799180 +0100
+++ new/src/hotspot/share/oops/arrayStorageProperties.hpp	2019-03-27 16:10:55.123446766 +0100
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_OOPS_ARRAYSTORAGEPROPERTIES_HPP
+#define SHARE_OOPS_ARRAYSTORAGEPROPERTIES_HPP
+
+#include "runtime/globals.hpp"
+
+class ArrayStorageProperties {
+ private:
+  uint8_t _flags;
+
+  void clear_flags_bits(uint8_t value) { _flags &= (~value); }
+  void set_flags_bits(uint8_t value) { _flags |= value; }
+  bool test_flags_bit(int idx) const { return (_flags & (1 << idx)) != 0; }
+ public:
+
+  enum {
+    empty_value           = 0,
+    flattened_bit         = 0,
+    flattened_value       = 1 <<  flattened_bit,
+    null_free_bit = flattened_bit + 1,
+    null_free_value = 1 << null_free_bit,
+    nof_oop_properties = null_free_bit + 1,
+  };
+
+  ArrayStorageProperties() : _flags(empty_value) {};
+  ArrayStorageProperties(uint8_t flags): _flags(flags) {};
+
+  bool is_empty() const { return _flags == empty_value; }
+
+  void clear_flattened()    { clear_flags_bits(flattened_value); }
+
+  bool is_flattened() const { return test_flags_bit(flattened_bit); }
+  void set_flattened()      { set_flags_bits(flattened_value); }
+
+  bool is_null_free() const { return test_flags_bit(null_free_bit); }
+  void set_null_free()      { set_flags_bits(null_free_value); }
+
+  uint8_t value() const { return _flags; }
+  template <typename T> T encode(int shift) const { return static_cast<T>(_flags) << shift; }
+
+  // Well-known constants...
+  static const ArrayStorageProperties empty;
+  static const ArrayStorageProperties flattened;
+  static const ArrayStorageProperties null_free;
+  static const ArrayStorageProperties flattened_and_null_free;
+};
+
+
+#endif //SHARE_OOPS_ARRAYSTORAGEPROPERTIES_HPP