/*

 * Copyright (c) 1997, 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_GC_IMPLEMENTATION_SHARED_MARKSWEEP_HPP

#define SHARE_VM_GC_IMPLEMENTATION_SHARED_MARKSWEEP_HPP

#include "gc_interface/collectedHeap.hpp"

#include "memory/genOopClosures.hpp"

#include "memory/iterator.hpp"

#include "oops/markOop.hpp"

#include "oops/oop.hpp"

#include "runtime/timer.hpp"

#include "utilities/growableArray.hpp"

#include "utilities/stack.hpp"

#include "utilities/taskqueue.hpp"

class ReferenceProcessor;

class DataLayout;

class SerialOldTracer;

class STWGCTimer;

// MarkSweep takes care of global mark-compact garbage collection for a

// GenCollectedHeap using a four-phase pointer forwarding algorithm.  All

// generations are assumed to support marking; those that can also support

// compaction.

//

// Class unloading will only occur when a full gc is invoked.

// declared at end

class PreservedMark;

class MarkSweep : AllStatic {

  //

  // Inline closure decls

  //

  class FollowRootClosure: public OopsInGenClosure {

   public:

    virtual void do_oop(oop* p);

    virtual void do_oop(narrowOop* p);

  };

  class MarkAndPushClosure: public OopClosure {

   public:

    virtual void do_oop(oop* p);

    virtual void do_oop(narrowOop* p);

  };

  class FollowStackClosure: public VoidClosure {

   public:

    virtual void do_void();

  };

  class AdjustPointerClosure: public OopsInGenClosure {

   public:

    virtual void do_oop(oop* p);

    virtual void do_oop(narrowOop* p);

  };

  // Used for java/lang/ref handling

  class IsAliveClosure: public BoolObjectClosure {

   public:

    virtual bool do_object_b(oop p);

  };

  class KeepAliveClosure: public OopClosure {

   protected:

    template <class T> void do_oop_work(T* p);

   public:

    virtual void do_oop(oop* p);

    virtual void do_oop(narrowOop* p);

  };

  //

  // Friend decls

  //

  friend class AdjustPointerClosure;

  friend class KeepAliveClosure;

  friend class VM_MarkSweep;

  friend void marksweep_init();

  //

  // Vars

  //

 protected:

  // Total invocations of a MarkSweep collection

  static uint _total_invocations;

  // Traversal stacks used during phase1

  static Stack<oop, mtGC>                      _marking_stack;

  static Stack<ObjArrayTask, mtGC>             _objarray_stack;

  // Space for storing/restoring mark word

  static Stack<markOop, mtGC>                  _preserved_mark_stack;

  static Stack<oop, mtGC>                      _preserved_oop_stack;

  static size_t                          _preserved_count;

  static size_t                          _preserved_count_max;

  static PreservedMark*                  _preserved_marks;

  // Reference processing (used in ...follow_contents)

  static ReferenceProcessor*             _ref_processor;

  static STWGCTimer*                     _gc_timer;

  static SerialOldTracer*                _gc_tracer;

  // Non public closures

  static KeepAliveClosure keep_alive;

  // Debugging

  static void trace(const char* msg) PRODUCT_RETURN;

 public:

  // Public closures

  static IsAliveClosure       is_alive;

  static FollowRootClosure    follow_root_closure;

  static MarkAndPushClosure   mark_and_push_closure;

  static FollowStackClosure   follow_stack_closure;

  static CLDToOopClosure      follow_cld_closure;

  static AdjustPointerClosure adjust_pointer_closure;

  static CLDToOopClosure      adjust_cld_closure;

  // Accessors

  static uint total_invocations() { return _total_invocations; }

  // Reference Processing

  static ReferenceProcessor* const ref_processor() { return _ref_processor; }

  static STWGCTimer* gc_timer() { return _gc_timer; }

  static SerialOldTracer* gc_tracer() { return _gc_tracer; }

  // Call backs for marking

  static void mark_object(oop obj);

  // Mark pointer and follow contents.  Empty marking stack afterwards.

  template <class T> static inline void follow_root(T* p);

  // Check mark and maybe push on marking stack

  template <class T> static void mark_and_push(T* p);

  static inline void push_objarray(oop obj, size_t index);

  static void follow_stack();   // Empty marking stack.

  static void follow_klass(Klass* klass);

  static void follow_class_loader(ClassLoaderData* cld);

  static void preserve_mark(oop p, markOop mark);

                                // Save the mark word so it can be restored later

  static void adjust_marks();   // Adjust the pointers in the preserved marks table

  static void restore_marks();  // Restore the marks that we saved in preserve_mark

  template <class T> static inline void adjust_pointer(T* p);

};

class PreservedMark VALUE_OBJ_CLASS_SPEC {

private:

  oop _obj;

  markOop _mark;

public:

  void init(oop obj, markOop mark) {

    _obj = obj;

    _mark = mark;

  }

  void adjust_pointer();

  void restore();

};

#endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_MARKSWEEP_HPP