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 /*

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

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  * 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_MEMORY_CARDTABLERS_HPP

 #define SHARE_VM_MEMORY_CARDTABLERS_HPP

 #include "memory/cardTableModRefBS.hpp"

 #include "memory/genRemSet.hpp"

 #include "memory/memRegion.hpp"

 class Space;

 class OopsInGenClosure;

 // This kind of "GenRemSet" uses a card table both as shared data structure

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

 class CardTableRS: public GenRemSet {

   friend class VMStructs;

   // Below are private classes used in impl.

   friend class VerifyCTSpaceClosure;

   friend class ClearNoncleanCardWrapper;

   static jbyte clean_card_val() {

     return CardTableModRefBS::clean_card;

   }

   static intptr_t clean_card_row() {

     return CardTableModRefBS::clean_card_row;

   }

   static bool

   card_is_dirty_wrt_gen_iter(jbyte cv) {

     return CardTableModRefBS::card_is_dirty_wrt_gen_iter(cv);

   }

   CardTableModRefBSForCTRS* _ct_bs;

   virtual void younger_refs_in_space_iterate(Space* sp, OopsInGenClosure* cl);

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

   enum ExtendedCardValue {

     youngergen_card   = CardTableModRefBS::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  = CardTableModRefBS::CT_MR_BS_last_reserved + 2,

     youngergenP2_card  = CardTableModRefBS::CT_MR_BS_last_reserved + 3,

     youngergenP3_card  = CardTableModRefBS::CT_MR_BS_last_reserved + 4,

     cur_youngergen_and_prev_nonclean_card =

       CardTableModRefBS::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; other gens are at

   // their level plus 1.  They youngest gen is in the table, but will

   // always have the value "clean_card".)

   jbyte* _last_cur_val_in_gen;

   jbyte _cur_youngergen_card_val;

   int _regions_to_iterate;

   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, int max_covered_regions);

   // *** GenRemSet functions.

   GenRemSet::Name rs_kind() { return GenRemSet::CardTable; }

   CardTableRS* as_CardTableRS() { return this; }

   CardTableModRefBS* ct_bs() { return _ct_bs; }

   // 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);

   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 verify_aligned_region_empty(MemRegion mr);

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

   void clear_into_younger(Generation* gen);

   void invalidate(MemRegion mr, bool whole_heap = false) {

     _ct_bs->invalidate(mr, whole_heap);

   }

   void invalidate_or_clear(Generation* gen, bool younger);

   static uintx ct_max_alignment_constraint() {

     return CardTableModRefBS::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);

   void do_MemRegion(MemRegion mr);

 };

 #endif // SHARE_VM_MEMORY_CARDTABLERS_HPP