/*
 * Copyright (c) 2015, 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
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#ifndef SHARE_VM_CLASSFILE_BACKTRACE_HPP
#define SHARE_VM_CLASSFILE_BACKTRACE_HPP

#include "memory/allocation.hpp"
#include "memory/iterator.hpp"
#include "oops/oop.inline.hpp"

// Backtrace management - Method* on backtraces need to be preserved for
// RedefineClasses, so we keep a list and mark them as on_stack so that the Method*
// doesn't get deallocatd.
// This list is managed as a weak root, but doesn't use jweak because
// the cost of creating these objects is performance critical.

class Backtrace : public CHeapObj<mtClass> {
  oop        _throwable;
  Backtrace* _next;

 public:
  Backtrace(oop throwable) : _throwable(throwable), _next(NULL) {}
  oop throwable()              { return _throwable; }
  Backtrace* next() const      { return _next; }
  void set_next(Backtrace* bt) { _next = bt; }
  // GC support
  void oops_do(OopClosure* f);
};

class BacktraceList : public AllStatic {
  // List of backtraces to mark Method pointers.
  static Backtrace* _backtraces_head;
  static volatile int _bt_count;

 public:
  static void mark_on_stack();
  static void unlink(BoolObjectClosure* is_alive);
  static void add(oop throwable);
  static void oops_do(OopClosure* f);
};

#endif // SHARE_VM_CLASSFILE_BACKTRACE_HPP