/*

 * Copyright 2001-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

class Space;

class OopsInGenClosure;

class DirtyCardToOopClosure;

// 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 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;

  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(oop* field, oop new_val) {

    jbyte* byte = _ct_bs.byte_for(field);

    *byte = youngergen_card;

  }

  void write_ref_field_gc_work(oop* 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(oop* 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_empty(MemRegion mr);

  void clear(MemRegion mr) { _ct_bs.clear(mr); }

  void clear_into_younger(Generation* gen, bool clear_perm);

  void invalidate(MemRegion mr) { _ct_bs.invalidate(mr); }

  void invalidate_or_clear(Generation* gen, bool younger, bool perm);

  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;

  }

};