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Java example source code file (compiledICHolder.hpp)

This example Java source code file (compiledICHolder.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

assert, atomic\:\:dec, atomic\:\:inc, cheapobj, compiledicholder, klass, method, share_vm_oops_compiledicholderoop_hpp, vmstructs

The compiledICHolder.hpp Java example source code

/*
 * Copyright (c) 1998, 2012, 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_COMPILEDICHOLDEROOP_HPP
#define SHARE_VM_OOPS_COMPILEDICHOLDEROOP_HPP

#include "oops/oop.hpp"

// A CompiledICHolder* is a helper object for the inline cache implementation.
// It holds an intermediate value (method+klass pair) used when converting from
// compiled to an interpreted 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

  Method* _holder_method;
  Klass*    _holder_klass;    // to avoid name conflict with oopDesc::_klass
  CompiledICHolder* _next;

 public:
  // Constructor
  CompiledICHolder(Method* method, Klass* klass)
      : _holder_method(method), _holder_klass(klass) {
#ifdef ASSERT
    Atomic::inc(&_live_count);
    Atomic::inc(&_live_not_claimed_count);
#endif
  }

  ~CompiledICHolder() {
#ifdef ASSERT
    assert(_live_count > 0, "underflow");
    Atomic::dec(&_live_count);
#endif
  }

  static int live_count() { return _live_count; }
  static int live_not_claimed_count() { return _live_not_claimed_count; }

  // accessors
  Method* holder_method() const     { return _holder_method; }
  Klass*    holder_klass()  const     { return _holder_klass; }

  void set_holder_method(Method* m) { _holder_method = m; }
  void set_holder_klass(Klass* k)   { _holder_klass = k; }

  // interpreter support (offsets in bytes)
  static int holder_method_offset()   { return offset_of(CompiledICHolder, _holder_method); }
  static int holder_klass_offset()    { return offset_of(CompiledICHolder, _holder_klass); }

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

  // 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() {
#ifdef ASSERT
    Atomic::dec(&_live_not_claimed_count);
#endif
  }
};

#endif // SHARE_VM_OOPS_COMPILEDICHOLDEROOP_HPP

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