view src/share/vm/oops/klassOop.hpp @ 3917:eca1193ca245

4965777: GC changes to support use of discovered field for pending references Summary: If and when the reference handler thread is able to use the discovered field to link reference objects in its pending list, so will GC. In that case, GC will scan through this field once a reference object has been placed on the pending list, but not scan that field before that stage, as the field is used by the concurrent GC thread to link discovered objects. When ReferenceHandleR thread does not use the discovered field for the purpose of linking the elements in the pending list, as would be the case in older JDKs, the JVM will fall back to the old behaviour of using the next field for that purpose. Reviewed-by: jcoomes, mchung, stefank
author ysr
date Wed, 07 Sep 2011 13:55:42 -0700
parents c7f3d0b4570f
children b0efc7ee3b31
line wrap: on
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/*
 * Copyright (c) 1997, 2011, 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_KLASSOOP_HPP
#define SHARE_VM_OOPS_KLASSOOP_HPP

#include "oops/oop.hpp"

// A klassOop is the C++ equivalent of a Java class.
// Part of a klassOopDesc is a Klass which handle the
// dispatching for the C++ method calls.

//  klassOop object layout:
//    [header     ]
//    [klass_field]
//    [KLASS      ]

class klassOopDesc : public oopDesc {
 public:
  // size operation
  static int header_size()                       { return sizeof(klassOopDesc)/HeapWordSize; }

  // support for code generation
  static int klass_part_offset_in_bytes()        { return sizeof(klassOopDesc); }

  // returns the Klass part containing dispatching behavior
  Klass* klass_part() const                      { return (Klass*)((address)this + klass_part_offset_in_bytes()); }

  // Convenience wrapper
  inline oop java_mirror() const;

 private:
  // These have no implementation since klassOop should never be accessed in this fashion
  oop obj_field(int offset) const;
  void obj_field_put(int offset, oop value);
  void obj_field_raw_put(int offset, oop value);

  jbyte byte_field(int offset) const;
  void byte_field_put(int offset, jbyte contents);

  jchar char_field(int offset) const;
  void char_field_put(int offset, jchar contents);

  jboolean bool_field(int offset) const;
  void bool_field_put(int offset, jboolean contents);

  jint int_field(int offset) const;
  void int_field_put(int offset, jint contents);

  jshort short_field(int offset) const;
  void short_field_put(int offset, jshort contents);

  jlong long_field(int offset) const;
  void long_field_put(int offset, jlong contents);

  jfloat float_field(int offset) const;
  void float_field_put(int offset, jfloat contents);

  jdouble double_field(int offset) const;
  void double_field_put(int offset, jdouble contents);

  address address_field(int offset) const;
  void address_field_put(int offset, address contents);

  oop obj_field_acquire(int offset) const;
  void release_obj_field_put(int offset, oop value);

  jbyte byte_field_acquire(int offset) const;
  void release_byte_field_put(int offset, jbyte contents);

  jchar char_field_acquire(int offset) const;
  void release_char_field_put(int offset, jchar contents);

  jboolean bool_field_acquire(int offset) const;
  void release_bool_field_put(int offset, jboolean contents);

  jint int_field_acquire(int offset) const;
  void release_int_field_put(int offset, jint contents);

  jshort short_field_acquire(int offset) const;
  void release_short_field_put(int offset, jshort contents);

  jlong long_field_acquire(int offset) const;
  void release_long_field_put(int offset, jlong contents);

  jfloat float_field_acquire(int offset) const;
  void release_float_field_put(int offset, jfloat contents);

  jdouble double_field_acquire(int offset) const;
  void release_double_field_put(int offset, jdouble contents);

  address address_field_acquire(int offset) const;
  void release_address_field_put(int offset, address contents);
};

#endif // SHARE_VM_OOPS_KLASSOOP_HPP