diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/oops/array.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/oops/array.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,161 @@
+/*
+ * Copyright (c) 2000, 2017, 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_VM_OOPS_ARRAY_HPP
+#define SHARE_VM_OOPS_ARRAY_HPP
+
+#include "memory/allocation.hpp"
+#include "memory/allocation.inline.hpp"
+#include "memory/metaspace.hpp"
+#include "runtime/orderAccess.hpp"
+#include "utilities/align.hpp"
+
+// Array for metadata allocation
+
+template <typename T>
+class Array: public MetaspaceObj {
+  friend class MetadataFactory;
+  friend class MetaspaceShared;
+  friend class VMStructs;
+  friend class JVMCIVMStructs;
+  friend class MethodHandleCompiler;           // special case
+  friend class WhiteBox;
+protected:
+  int _length;                                 // the number of array elements
+  T   _data[1];                                // the array memory
+
+  void initialize(int length) {
+    _length = length;
+  }
+
+ private:
+  // Turn off copy constructor and assignment operator.
+  Array(const Array<T>&);
+  void operator=(const Array<T>&);
+
+  void* operator new(size_t size, ClassLoaderData* loader_data, int length, TRAPS) throw() {
+    size_t word_size = Array::size(length);
+    return (void*) Metaspace::allocate(loader_data, word_size,
+                                       MetaspaceObj::array_type(sizeof(T)), THREAD);
+  }
+
+  static size_t byte_sizeof(int length, size_t elm_byte_size) {
+    return sizeof(Array<T>) + MAX2(length - 1, 0) * elm_byte_size;
+  }
+  static size_t byte_sizeof(int length) { return byte_sizeof(length, sizeof(T)); }
+
+  // WhiteBox API helper.
+  // Can't distinguish between array of length 0 and length 1,
+  // will always return 0 in those cases.
+  static int bytes_to_length(size_t bytes)       {
+    assert(is_aligned(bytes, BytesPerWord), "Must be, for now");
+
+    if (sizeof(Array<T>) >= bytes) {
+      return 0;
+    }
+
+    size_t left = bytes - sizeof(Array<T>);
+    assert(is_aligned(left, sizeof(T)), "Must be");
+
+    size_t elements = left / sizeof(T);
+    assert(elements <= (size_t)INT_MAX, "number of elements " SIZE_FORMAT "doesn't fit into an int.", elements);
+
+    int length = (int)elements;
+
+    assert((size_t)size(length) * BytesPerWord == (size_t)bytes,
+           "Expected: " SIZE_FORMAT " got: " SIZE_FORMAT,
+           bytes, (size_t)size(length) * BytesPerWord);
+
+    return length;
+  }
+
+  explicit Array(int length) : _length(length) {
+    assert(length >= 0, "illegal length");
+  }
+
+  Array(int length, T init) : _length(length) {
+    assert(length >= 0, "illegal length");
+    for (int i = 0; i < length; i++) {
+      _data[i] = init;
+    }
+  }
+
+ public:
+
+  // standard operations
+  int  length() const                 { return _length; }
+  T* data()                           { return _data; }
+  bool is_empty() const               { return length() == 0; }
+
+  int index_of(const T& x) const {
+    int i = length();
+    while (i-- > 0 && _data[i] != x) ;
+
+    return i;
+  }
+
+  // sort the array.
+  bool contains(const T& x) const      { return index_of(x) >= 0; }
+
+  T    at(int i) const                 { assert(i >= 0 && i< _length, "oob: 0 <= %d < %d", i, _length); return _data[i]; }
+  void at_put(const int i, const T& x) { assert(i >= 0 && i< _length, "oob: 0 <= %d < %d", i, _length); _data[i] = x; }
+  T*   adr_at(const int i)             { assert(i >= 0 && i< _length, "oob: 0 <= %d < %d", i, _length); return &_data[i]; }
+  int  find(const T& x)                { return index_of(x); }
+
+  T at_acquire(const int which)              { return OrderAccess::load_acquire(adr_at(which)); }
+  void release_at_put(int which, T contents) { OrderAccess::release_store(adr_at(which), contents); }
+
+  static int size(int length) {
+    size_t bytes = align_up(byte_sizeof(length), BytesPerWord);
+    size_t words = bytes / BytesPerWord;
+
+    assert(words <= INT_MAX, "Overflow: " SIZE_FORMAT, words);
+
+    return (int)words;
+  }
+  int size() {
+    return size(_length);
+  }
+
+  static int length_offset_in_bytes() { return (int) (offset_of(Array<T>, _length)); }
+  // Note, this offset don't have to be wordSize aligned.
+  static int base_offset_in_bytes() { return (int) (offset_of(Array<T>, _data)); };
+
+  // FIXME: How to handle this?
+  void print_value_on(outputStream* st) const {
+    st->print("Array<T>(" INTPTR_FORMAT ")", p2i(this));
+  }
+
+#ifndef PRODUCT
+  void print(outputStream* st) {
+     for (int i = 0; i< _length; i++) {
+       st->print_cr("%d: " INTPTR_FORMAT, i, (intptr_t)at(i));
+     }
+  }
+  void print() { print(tty); }
+#endif // PRODUCT
+};
+
+
+#endif // SHARE_VM_OOPS_ARRAY_HPP