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Java example source code file (instanceMirrorKlass.hpp)

This example Java source code file (instanceMirrorKlass.hpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

all_oop_oop_iterate_closures_1, all_oop_oop_iterate_closures_2, cds, extendedoopclosure, include_all_gcs, instanceklass, instancemirrorklass, instancemirrorklass_oop_oop_iterate_backwards_decl, memregion, oopclosuretype, referencetype, share_vm_oops_instancemirrorklass_hpp, traps, usesharedspaces

The instanceMirrorKlass.hpp Java example source code

/*
 * Copyright (c) 2011, 2013, 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 "oops/instanceKlass.hpp"
#include "runtime/handles.hpp"
#include "utilities/macros.hpp"

// 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;

  // Constructor
  InstanceMirrorKlass(int vtable_len, int itable_len, int static_field_size, int nonstatic_oop_map_size, ReferenceType rt, AccessFlags access_flags,  bool is_anonymous)
    : InstanceKlass(vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt, access_flags, is_anonymous) {}

 public:
  InstanceMirrorKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
  // Type testing
  bool oop_is_instanceMirror() const             { return true; }

  // Casting from Klass*
  static InstanceMirrorKlass* cast(Klass* k) {
    assert(k->oop_is_instanceMirror(), "cast to InstanceMirrorKlass");
    return (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(KlassHandle k);

  // allocation
  instanceOop allocate_instance(KlassHandle k, TRAPS);

  // Garbage collection
  int  oop_adjust_pointers(oop obj);
  void oop_follow_contents(oop obj);

  // Parallel Scavenge and Parallel Old
  PARALLEL_GC_DECLS

  int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) {
    return oop_oop_iterate_v(obj, blk);
  }
  int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) {
    return oop_oop_iterate_v_m(obj, blk, mr);
  }

#define InstanceMirrorKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix)           \
  int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk);                       \
  int oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk, MemRegion mr);

  ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceMirrorKlass_OOP_OOP_ITERATE_DECL)
  ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceMirrorKlass_OOP_OOP_ITERATE_DECL)

#if INCLUDE_ALL_GCS
#define InstanceMirrorKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
  int oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk);

  ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceMirrorKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
  ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceMirrorKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
#endif // INCLUDE_ALL_GCS
};

#endif // SHARE_VM_OOPS_INSTANCEMIRRORKLASS_HPP

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