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Java example source code file (basicLock.hpp)

This example Java source code file (basicLock.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

basiclock, basicobjectlock, share_vm_runtime_basiclock_hpp, value_obj_class_spec, vmstructs

The basicLock.hpp Java example source code

/*
 * Copyright (c) 1998, 2010, 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_RUNTIME_BASICLOCK_HPP
#define SHARE_VM_RUNTIME_BASICLOCK_HPP

#include "oops/markOop.hpp"
#include "runtime/handles.hpp"
#include "utilities/top.hpp"

class BasicLock VALUE_OBJ_CLASS_SPEC {
  friend class VMStructs;
 private:
  volatile markOop _displaced_header;
 public:
  markOop      displaced_header() const               { return _displaced_header; }
  void         set_displaced_header(markOop header)   { _displaced_header = header; }

  void print_on(outputStream* st) const;

  // move a basic lock (used during deoptimization
  void move_to(oop obj, BasicLock* dest);

  static int displaced_header_offset_in_bytes()       { return offset_of(BasicLock, _displaced_header); }
};

// A BasicObjectLock associates a specific Java object with a BasicLock.
// It is currently embedded in an interpreter frame.

// Because some machines have alignment restrictions on the control stack,
// the actual space allocated by the interpreter may include padding words
// after the end of the BasicObjectLock.  Also, in order to guarantee
// alignment of the embedded BasicLock objects on such machines, we
// put the embedded BasicLock at the beginning of the struct.

class BasicObjectLock VALUE_OBJ_CLASS_SPEC {
  friend class VMStructs;
 private:
  BasicLock _lock;                                    // the lock, must be double word aligned
  oop       _obj;                                     // object holds the lock;

 public:
  // Manipulation
  oop      obj() const                                { return _obj;  }
  void set_obj(oop obj)                               { _obj = obj; }
  BasicLock* lock()                                   { return &_lock; }

  // Note: Use frame::interpreter_frame_monitor_size() for the size of BasicObjectLocks
  //       in interpreter activation frames since it includes machine-specific padding.
  static int size()                                   { return sizeof(BasicObjectLock)/wordSize; }

  // GC support
  void oops_do(OopClosure* f) { f->do_oop(&_obj); }

  static int obj_offset_in_bytes()                    { return offset_of(BasicObjectLock, _obj);  }
  static int lock_offset_in_bytes()                   { return offset_of(BasicObjectLock, _lock); }
};


#endif // SHARE_VM_RUNTIME_BASICLOCK_HPP

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