src/hotspot/share/gc/z/zNMethodTableEntry.hpp

/*
 * Copyright (c) 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_GC_Z_ZNMETHODTABLEENTRY_HPP
#define SHARE_GC_Z_ZNMETHODTABLEENTRY_HPP

#include "gc/z/zBitField.hpp"
#include "memory/allocation.hpp"

//
// NMethod table entry layout
// --------------------------
//
//   6
//   3                                                                  3 2 1 0
//  +--------------------------------------------------------------------+-+-+-+
//  |11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111|1|1|1|
//  +--------------------------------------------------------------------+-+-+-+
//  |                                                                    | | |
//  |                               2-2 Non-immediate Oops Flag (1-bits) * | |
//  |                                                                      | |
//  |                        1-1 Immediate Oops/Unregistered Flag (1-bits) * |
//  |                                                                        |
//  |                                           0-0 Registered Flag (1-bits) *
//  |
//  * 63-3 NMethod/ZNMethodWithImmediateOops Address (61-bits)
//

class nmethod;
class ZNMethodWithImmediateOops;

class ZNMethodTableEntry : public CHeapObj<mtGC> {
private:
  typedef ZBitField<uint64_t, bool,                       0,  1>    field_registered;
  typedef ZBitField<uint64_t, bool,                       1,  1>    field_unregistered;
  typedef ZBitField<uint64_t, bool,                       1,  1>    field_immediate_oops;
  typedef ZBitField<uint64_t, bool,                       2,  1>    field_non_immediate_oops;
  typedef ZBitField<uint64_t, nmethod*,                   3, 61, 3> field_method;
  typedef ZBitField<uint64_t, ZNMethodWithImmediateOops*, 3, 61, 3> field_method_with_immediate_oops;

  uint64_t _entry;

public:
  ZNMethodTableEntry(bool unregistered = false) :
      _entry(field_unregistered::encode(unregistered) |
             field_registered::encode(false)) {}

  ZNMethodTableEntry(nmethod* method, bool non_immediate_oops) :
      _entry(field_method::encode(method) |
             field_non_immediate_oops::encode(non_immediate_oops) |
             field_immediate_oops::encode(false) |
             field_registered::encode(true)) {}

  ZNMethodTableEntry(ZNMethodWithImmediateOops* method_with_immediate_oops, bool non_immediate_oops) :
      _entry(field_method_with_immediate_oops::encode(method_with_immediate_oops) |
             field_non_immediate_oops::encode(non_immediate_oops) |
             field_immediate_oops::encode(true) |
             field_registered::encode(true)) {}

  bool registered() const {
    return field_registered::decode(_entry);
  }

  bool unregistered() const {
    return field_unregistered::decode(_entry);
  }

  bool immediate_oops() const {
    return field_immediate_oops::decode(_entry);
  }

  bool non_immediate_oops() const {
    return field_non_immediate_oops::decode(_entry);
  }

  nmethod* method() const {
    return field_method::decode(_entry);
  }

  ZNMethodWithImmediateOops* method_with_immediate_oops() const {
    return field_method_with_immediate_oops::decode(_entry);
  }
};

#endif // SHARE_GC_Z_ZNMETHODTABLEENTRY_HPP