/*

 * Copyright (c) 1998, 2019, 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.

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 */

#ifndef SHARE_OOPS_COMPILEDICHOLDER_HPP

#define SHARE_OOPS_COMPILEDICHOLDER_HPP

#include "oops/oop.hpp"

#include "utilities/macros.hpp"

#include "oops/klass.hpp"

#include "oops/method.hpp"

// A CompiledICHolder* is a helper object for the inline cache implementation.

// It holds:

//   (1) (method+klass pair) when converting from compiled to an interpreted call

//   (2) (klass+klass pair) when calling itable stub from megamorphic compiled call

//

// These are always allocated in the C heap and are freed during a

// safepoint by the ICBuffer logic.  It's unsafe to free them earlier

// since they might be in use.

//

class CompiledICHolder : public CHeapObj<mtCompiler> {

  friend class VMStructs;

 private:

  static volatile int _live_count; // allocated

  static volatile int _live_not_claimed_count; // allocated but not yet in use so not

                                               // reachable by iterating over nmethods

  Metadata* _holder_metadata;

  Klass*    _holder_klass;    // to avoid name conflict with oopDesc::_klass

  CompiledICHolder* _next;

  bool _is_metadata_method;

 public:

  // Constructor

  CompiledICHolder(Metadata* metadata, Klass* klass, bool is_method = true);

  ~CompiledICHolder() NOT_DEBUG_RETURN;

  static int live_count() { return _live_count; }

  static int live_not_claimed_count() { return _live_not_claimed_count; }

  // accessors

  Klass*    holder_klass()  const     { return _holder_klass; }

  Metadata* holder_metadata() const   { return _holder_metadata; }

  static int holder_metadata_offset() { return offset_of(CompiledICHolder, _holder_metadata); }

  static int holder_klass_offset()    { return offset_of(CompiledICHolder, _holder_klass); }

  CompiledICHolder* next()     { return _next; }

  void set_next(CompiledICHolder* n) { _next = n; }

  inline bool is_loader_alive() {

    Klass* k = _is_metadata_method ? ((Method*)_holder_metadata)->method_holder() : (Klass*)_holder_metadata;

    if (!k->is_loader_alive()) {

      return false;

    }

    if (!_holder_klass->is_loader_alive()) {

      return false;

    }

    return true;

  }

  // Verify

  void verify_on(outputStream* st);

  // Printing

  void print_on(outputStream* st) const;

  void print_value_on(outputStream* st) const;

  const char* internal_name() const { return "{compiledICHolder}"; }

  void claim() NOT_DEBUG_RETURN;

};

#endif // SHARE_OOPS_COMPILEDICHOLDER_HPP