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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 * 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.

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#ifndef SHARE_VM_GC_SHARED_CARDTABLERS_HPP

#define SHARE_VM_GC_SHARED_CARDTABLERS_HPP

#include "gc/shared/cardTableModRefBSForCTRS.hpp"

#include "memory/memRegion.hpp"

class Space;

class OopsInGenClosure;

// Helper to remember modified oops in all clds.

class CLDRemSet {

  bool _accumulate_modified_oops;

 public:

  CLDRemSet() : _accumulate_modified_oops(false) {}

  void set_accumulate_modified_oops(bool value) { _accumulate_modified_oops = value; }

  bool accumulate_modified_oops() { return _accumulate_modified_oops; }

  bool mod_union_is_clear();

  void clear_mod_union();

};

// This RemSet uses a card table both as shared data structure

// for a mod ref barrier set and for the rem set information.

class CardTableRS: public CHeapObj<mtGC> {

  friend class VMStructs;

  // Below are private classes used in impl.

  friend class VerifyCTSpaceClosure;

  friend class ClearNoncleanCardWrapper;

  static jbyte clean_card_val() {

    return CardTableModRefBSForCTRS::clean_card;

  }

  static intptr_t clean_card_row() {

    return CardTableModRefBSForCTRS::clean_card_row;

  }

  static bool

  card_is_dirty_wrt_gen_iter(jbyte cv) {

    return CardTableModRefBSForCTRS::card_is_dirty_wrt_gen_iter(cv);

  }

  CLDRemSet _cld_rem_set;

  BarrierSet* _bs;

  CardTableModRefBSForCTRS* _ct_bs;

  void verify_space(Space* s, HeapWord* gen_start);

  enum ExtendedCardValue {

    youngergen_card   = CardTableModRefBSForCTRS::CT_MR_BS_last_reserved + 1,

    // These are for parallel collection.

    // There are three P (parallel) youngergen card values.  In general, this

    // needs to be more than the number of generations (including the perm

    // gen) that might have younger_refs_do invoked on them separately.  So

    // if we add more gens, we have to add more values.

    youngergenP1_card  = CardTableModRefBSForCTRS::CT_MR_BS_last_reserved + 2,

    youngergenP2_card  = CardTableModRefBSForCTRS::CT_MR_BS_last_reserved + 3,

    youngergenP3_card  = CardTableModRefBSForCTRS::CT_MR_BS_last_reserved + 4,

    cur_youngergen_and_prev_nonclean_card =

      CardTableModRefBSForCTRS::CT_MR_BS_last_reserved + 5

  };

  // An array that contains, for each generation, the card table value last

  // used as the current value for a younger_refs_do iteration of that

  // portion of the table. The perm gen is index 0. The young gen is index 1,

  // but will always have the value "clean_card". The old gen is index 2.

  jbyte* _last_cur_val_in_gen;

  jbyte _cur_youngergen_card_val;

  // Number of generations, plus one for lingering PermGen issues in CardTableRS.

  static const int _regions_to_iterate = 3;

  jbyte cur_youngergen_card_val() {

    return _cur_youngergen_card_val;

  }

  void set_cur_youngergen_card_val(jbyte v) {

    _cur_youngergen_card_val = v;

  }

  bool is_prev_youngergen_card_val(jbyte v) {

    return

      youngergen_card <= v &&

      v < cur_youngergen_and_prev_nonclean_card &&

      v != _cur_youngergen_card_val;

  }

  // Return a youngergen_card_value that is not currently in use.

  jbyte find_unused_youngergenP_card_value();

public:

  CardTableRS(MemRegion whole_heap);

  ~CardTableRS();

  // Return the barrier set associated with "this."

  BarrierSet* bs() { return _bs; }

  // Set the barrier set.

  void set_bs(BarrierSet* bs) { _bs = bs; }

  CLDRemSet* cld_rem_set() { return &_cld_rem_set; }

  CardTableModRefBSForCTRS* ct_bs() { return _ct_bs; }

  void younger_refs_in_space_iterate(Space* sp, OopsInGenClosure* cl, uint n_threads);

  // Override.

  void prepare_for_younger_refs_iterate(bool parallel);

  // Card table entries are cleared before application; "blk" is

  // responsible for dirtying if the oop is still older-to-younger after

  // closure application.

  void younger_refs_iterate(Generation* g, OopsInGenClosure* blk, uint n_threads);

  void inline_write_ref_field_gc(void* field, oop new_val) {

    jbyte* byte = _ct_bs->byte_for(field);

    *byte = youngergen_card;

  }

  void write_ref_field_gc_work(void* field, oop new_val) {

    inline_write_ref_field_gc(field, new_val);

  }

  // Override.  Might want to devirtualize this in the same fashion as

  // above.  Ensures that the value of the card for field says that it's

  // a younger card in the current collection.

  virtual void write_ref_field_gc_par(void* field, oop new_val);

  void resize_covered_region(MemRegion new_region);

  bool is_aligned(HeapWord* addr) {

    return _ct_bs->is_card_aligned(addr);

  }

  void verify();

  void clear(MemRegion mr) { _ct_bs->clear(mr); }

  void clear_into_younger(Generation* old_gen);

  void invalidate(MemRegion mr) {

    _ct_bs->invalidate(mr);

  }

  void invalidate_or_clear(Generation* old_gen);

  static uintx ct_max_alignment_constraint() {

    return CardTableModRefBSForCTRS::ct_max_alignment_constraint();

  }

  jbyte* byte_for(void* p)     { return _ct_bs->byte_for(p); }

  jbyte* byte_after(void* p)   { return _ct_bs->byte_after(p); }

  HeapWord* addr_for(jbyte* p) { return _ct_bs->addr_for(p); }

  bool is_prev_nonclean_card_val(jbyte v) {

    return

      youngergen_card <= v &&

      v <= cur_youngergen_and_prev_nonclean_card &&

      v != _cur_youngergen_card_val;

  }

  static bool youngergen_may_have_been_dirty(jbyte cv) {

    return cv == CardTableRS::cur_youngergen_and_prev_nonclean_card;

  }

};

class ClearNoncleanCardWrapper: public MemRegionClosure {

  DirtyCardToOopClosure* _dirty_card_closure;

  CardTableRS* _ct;

  bool _is_par;

private:

  // Clears the given card, return true if the corresponding card should be

  // processed.

  inline bool clear_card(jbyte* entry);

  // Work methods called by the clear_card()

  inline bool clear_card_serial(jbyte* entry);

  inline bool clear_card_parallel(jbyte* entry);

  // check alignment of pointer

  bool is_word_aligned(jbyte* entry);

public:

  ClearNoncleanCardWrapper(DirtyCardToOopClosure* dirty_card_closure, CardTableRS* ct, bool is_par);

  void do_MemRegion(MemRegion mr);

};

#endif // SHARE_VM_GC_SHARED_CARDTABLERS_HPP