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 * Copyright (c) 2001, 2018, 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_SHARED_GENOOPCLOSURES_HPP

#define SHARE_VM_GC_SHARED_GENOOPCLOSURES_HPP

#include "memory/iterator.hpp"

#include "oops/oop.hpp"

class Generation;

class HeapWord;

class CardTableRS;

class CardTableBarrierSet;

class DefNewGeneration;

class KlassRemSet;

// Closure for iterating roots from a particular generation

// Note: all classes deriving from this MUST call this do_barrier

// method at the end of their own do_oop method!

// Note: no do_oop defined, this is an abstract class.

class OopsInGenClosure : public ExtendedOopClosure {

 private:

  Generation*  _orig_gen;     // generation originally set in ctor

  Generation*  _gen;          // generation being scanned

 protected:

  // Some subtypes need access.

  HeapWord*    _gen_boundary; // start of generation

  CardTableRS* _rs;           // remembered set

  // For assertions

  Generation* generation() { return _gen; }

  CardTableRS* rs() { return _rs; }

  // Derived classes that modify oops so that they might be old-to-young

  // pointers must call the method below.

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

  // Version for use by closures that may be called in parallel code.

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

 public:

  OopsInGenClosure() : ExtendedOopClosure(NULL),

    _orig_gen(NULL), _gen(NULL), _gen_boundary(NULL), _rs(NULL) {};

  OopsInGenClosure(Generation* gen);

  void set_generation(Generation* gen);

  void reset_generation() { _gen = _orig_gen; }

  // Problem with static closures: must have _gen_boundary set at some point,

  // but cannot do this until after the heap is initialized.

  void set_orig_generation(Generation* gen) {

    _orig_gen = gen;

    set_generation(gen);

  }

  HeapWord* gen_boundary() { return _gen_boundary; }

};

// Super class for scan closures. It contains code to dirty scanned class loader data.

class OopsInClassLoaderDataOrGenClosure: public OopsInGenClosure {

  ClassLoaderData* _scanned_cld;

 public:

  OopsInClassLoaderDataOrGenClosure(Generation* g) : OopsInGenClosure(g), _scanned_cld(NULL) {}

  void set_scanned_cld(ClassLoaderData* cld) {

    assert(cld == NULL || _scanned_cld == NULL, "Must be");

    _scanned_cld = cld;

  }

  bool is_scanning_a_cld() { return _scanned_cld != NULL; }

  void do_cld_barrier();

};

#if INCLUDE_SERIALGC

// Closure for scanning DefNewGeneration.

//

// This closure will perform barrier store calls for ALL

// pointers in scanned oops.

class ScanClosure: public OopsInClassLoaderDataOrGenClosure {

 protected:

  DefNewGeneration* _g;

  HeapWord*         _boundary;

  bool              _gc_barrier;

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

 public:

  ScanClosure(DefNewGeneration* g, bool gc_barrier);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p);

  inline void do_oop_nv(narrowOop* p);

};

// Closure for scanning DefNewGeneration.

//

// This closure only performs barrier store calls on

// pointers into the DefNewGeneration. This is less

// precise, but faster, than a ScanClosure

class FastScanClosure: public OopsInClassLoaderDataOrGenClosure {

 protected:

  DefNewGeneration* _g;

  HeapWord*         _boundary;

  bool              _gc_barrier;

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

 public:

  FastScanClosure(DefNewGeneration* g, bool gc_barrier);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p);

  inline void do_oop_nv(narrowOop* p);

};

#endif // INCLUDE_SERIALGC

class CLDScanClosure: public CLDClosure {

  OopsInClassLoaderDataOrGenClosure*   _scavenge_closure;

  // true if the the modified oops state should be saved.

  bool                                 _accumulate_modified_oops;

 public:

  CLDScanClosure(OopsInClassLoaderDataOrGenClosure* scavenge_closure,

                 bool accumulate_modified_oops) :

       _scavenge_closure(scavenge_closure), _accumulate_modified_oops(accumulate_modified_oops) {}

  void do_cld(ClassLoaderData* cld);

};

class FilteringClosure: public ExtendedOopClosure {

 private:

  HeapWord*   _boundary;

  ExtendedOopClosure* _cl;

 protected:

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

 public:

  FilteringClosure(HeapWord* boundary, ExtendedOopClosure* cl) :

    ExtendedOopClosure(cl->ref_discoverer()), _boundary(boundary),

    _cl(cl) {}

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p);

  inline void do_oop_nv(narrowOop* p);

  virtual bool do_metadata()          { return do_metadata_nv(); }

  inline bool do_metadata_nv()        { assert(!_cl->do_metadata(), "assumption broken, must change to 'return _cl->do_metadata()'"); return false; }

};

#if INCLUDE_SERIALGC

// Closure for scanning DefNewGeneration's weak references.

// NOTE: very much like ScanClosure but not derived from

//  OopsInGenClosure -- weak references are processed all

//  at once, with no notion of which generation they were in.

class ScanWeakRefClosure: public OopClosure {

 protected:

  DefNewGeneration* _g;

  HeapWord*         _boundary;

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

 public:

  ScanWeakRefClosure(DefNewGeneration* g);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p);

  inline void do_oop_nv(narrowOop* p);

};

#endif // INCLUDE_SERIALGC

#endif // SHARE_VM_GC_SHARED_GENOOPCLOSURES_HPP