diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/oops/instanceMirrorKlass.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/oops/instanceMirrorKlass.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2011, 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_INSTANCEMIRRORKLASS_HPP
+#define SHARE_VM_OOPS_INSTANCEMIRRORKLASS_HPP
+
+#include "classfile/systemDictionary.hpp"
+#include "gc/shared/specialized_oop_closures.hpp"
+#include "oops/instanceKlass.hpp"
+#include "runtime/handles.hpp"
+#include "utilities/macros.hpp"
+
+class ClassFileParser;
+
+// An InstanceMirrorKlass is a specialized InstanceKlass for
+// java.lang.Class instances.  These instances are special because
+// they contain the static fields of the class in addition to the
+// normal fields of Class.  This means they are variable sized
+// instances and need special logic for computing their size and for
+// iteration of their oops.
+
+
+class InstanceMirrorKlass: public InstanceKlass {
+  friend class VMStructs;
+  friend class InstanceKlass;
+
+ private:
+  static int _offset_of_static_fields;
+
+  InstanceMirrorKlass(const ClassFileParser& parser) : InstanceKlass(parser, InstanceKlass::_misc_kind_mirror) {}
+
+ public:
+  InstanceMirrorKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
+
+  // Casting from Klass*
+  static InstanceMirrorKlass* cast(Klass* k) {
+    assert(InstanceKlass::cast(k)->is_mirror_instance_klass(),
+           "cast to InstanceMirrorKlass");
+    return static_cast<InstanceMirrorKlass*>(k);
+  }
+
+  // Returns the size of the instance including the extra static fields.
+  virtual int oop_size(oop obj) const;
+
+  // Static field offset is an offset into the Heap, should be converted by
+  // based on UseCompressedOop for traversal
+  static HeapWord* start_of_static_fields(oop obj) {
+    return (HeapWord*)(cast_from_oop<intptr_t>(obj) + offset_of_static_fields());
+  }
+
+  static void init_offset_of_static_fields() {
+    // Cache the offset of the static fields in the Class instance
+    assert(_offset_of_static_fields == 0, "once");
+    _offset_of_static_fields = InstanceMirrorKlass::cast(SystemDictionary::Class_klass())->size_helper() << LogHeapWordSize;
+  }
+
+  static int offset_of_static_fields() {
+    return _offset_of_static_fields;
+  }
+
+  int compute_static_oop_field_count(oop obj);
+
+  // Given a Klass return the size of the instance
+  int instance_size(Klass* k);
+
+  // allocation
+  instanceOop allocate_instance(Klass* k, TRAPS);
+
+  // GC specific object visitors
+  //
+#if INCLUDE_ALL_GCS
+  // Parallel Scavenge
+  void oop_ps_push_contents(  oop obj, PSPromotionManager* pm);
+  // Parallel Compact
+  void oop_pc_follow_contents(oop obj, ParCompactionManager* cm);
+  void oop_pc_update_pointers(oop obj, ParCompactionManager* cm);
+#endif
+
+  // Oop fields (and metadata) iterators
+  //  [nv = true]  Use non-virtual calls to do_oop_nv.
+  //  [nv = false] Use virtual calls to do_oop.
+  //
+  // The InstanceMirrorKlass iterators also visit the hidden Klass pointer.
+
+ public:
+  // Iterate over the static fields.
+  template <bool nv, class OopClosureType>
+  inline void oop_oop_iterate_statics(oop obj, OopClosureType* closure);
+
+ private:
+  // Iterate over the static fields.
+  // Specialized for [T = oop] or [T = narrowOop].
+  template <bool nv, typename T, class OopClosureType>
+  inline void oop_oop_iterate_statics_specialized(oop obj, OopClosureType* closure);
+
+  // Forward iteration
+  // Iterate over the oop fields and metadata.
+  template <bool nv, class OopClosureType>
+  inline void oop_oop_iterate(oop obj, OopClosureType* closure);
+
+
+  // Reverse iteration
+#if INCLUDE_ALL_GCS
+  // Iterate over the oop fields and metadata.
+  template <bool nv, class OopClosureType>
+  inline void oop_oop_iterate_reverse(oop obj, OopClosureType* closure);
+#endif
+
+
+  // Bounded range iteration
+  // Iterate over the oop fields and metadata.
+  template <bool nv, class OopClosureType>
+  inline void oop_oop_iterate_bounded(oop obj, OopClosureType* closure, MemRegion mr);
+
+  // Iterate over the static fields.
+  template <bool nv, class OopClosureType>
+  inline void oop_oop_iterate_statics_bounded(oop obj, OopClosureType* closure, MemRegion mr);
+
+  // Iterate over the static fields.
+  // Specialized for [T = oop] or [T = narrowOop].
+  template <bool nv, typename T, class OopClosureType>
+  inline void oop_oop_iterate_statics_specialized_bounded(oop obj, OopClosureType* closure, MemRegion mr);
+
+
+ public:
+
+  ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_OOP_ITERATE_DECL)
+  ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_OOP_ITERATE_DECL)
+
+#if INCLUDE_ALL_GCS
+  ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_OOP_ITERATE_DECL_BACKWARDS)
+  ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_OOP_ITERATE_DECL_BACKWARDS)
+#endif // INCLUDE_ALL_GCS
+};
+
+#endif // SHARE_VM_OOPS_INSTANCEMIRRORKLASS_HPP