src/hotspot/share/gc/serial/cardTableRS.hpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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#ifndef SHARE_GC_SERIAL_CARDTABLERS_HPP
#define SHARE_GC_SERIAL_CARDTABLERS_HPP

#include "gc/shared/cardTable.hpp"
#include "memory/memRegion.hpp"
#include "oops/oop.hpp"

class DirtyCardToOopClosure;
class Generation;
class Space;
class TenuredSpace;

// 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 CardTable {
  friend class VMStructs;
  // Below are private classes used in impl.
  friend class VerifyCTSpaceClosure;
  friend class ClearNoncleanCardWrapper;

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

public:
  CardTableRS(MemRegion whole_heap);

  void younger_refs_in_space_iterate(TenuredSpace* sp, OopIterateClosure* cl);

  virtual void verify_used_region_at_save_marks(Space* sp) const NOT_DEBUG_RETURN;

  void inline_write_ref_field_gc(void* field) {
    CardValue* byte = byte_for(field);
    *byte = dirty_card_val();
  }

  bool is_aligned(HeapWord* addr) {
    return is_card_aligned(addr);
  }

  void verify();

  // Update old gen cards to maintain old-to-young-pointer invariant: Clear
  // the old generation card table completely if the young generation had been
  // completely evacuated, otherwise dirties the whole old generation to
  // conservatively not loose any old-to-young pointer.
  void maintain_old_to_young_invariant(Generation* old_gen, bool is_young_gen_empty);

  // Iterate over the portion of the card-table which covers the given
  // region mr in the given space and apply cl to any dirty sub-regions
  // of mr. Clears the dirty cards as they are processed.
  void non_clean_card_iterate(TenuredSpace* sp,
                              MemRegion mr,
                              OopIterateClosure* cl,
                              CardTableRS* ct);

  bool is_in_young(const void* p) const override;
};

class ClearNoncleanCardWrapper: public MemRegionClosure {
  DirtyCardToOopClosure* _dirty_card_closure;
  CardTableRS* _ct;

public:

  typedef CardTable::CardValue CardValue;
private:
  // Clears the given card, return true if the corresponding card should be
  // processed.
  inline bool clear_card(CardValue* entry);
  // check alignment of pointer
  bool is_word_aligned(CardValue* entry);

public:
  ClearNoncleanCardWrapper(DirtyCardToOopClosure* dirty_card_closure, CardTableRS* ct);
  void do_MemRegion(MemRegion mr) override;
};

#endif // SHARE_GC_SERIAL_CARDTABLERS_HPP