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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 *

 * You should have received a copy of the GNU General Public License version

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#ifndef SHARE_VM_GC_G1_HEAPREGIONTYPE_HPP

#define SHARE_VM_GC_G1_HEAPREGIONTYPE_HPP

#include "gc/g1/g1HeapRegionTraceType.hpp"

#define hrt_assert_is_valid(tag) \

  assert(is_valid((tag)), "invalid HR type: %u", (uint) (tag))

friend class VMStructs;

private:

  // We encode the value of the heap region type so the generation can be

  // determined quickly. The tag is split into two parts:

  //

  //   major type (young, old, humongous, archive)           : top N-1 bits

  //   minor type (eden / survivor, starts / cont hum, etc.) : bottom 1 bit

  //

  // If there's need to increase the number of minor types in the

  // future, we'll have to increase the size of the latter and hence

  // decrease the size of the former.

  //

  // 00000 0 [ 0] Free

  //

  // 00001 0 [ 2] Young Mask

  // 00001 0 [ 2] Eden

  // 00001 1 [ 3] Survivor

  //

  // 00010 0 [ 4] Humongous Mask

  // 00100 0 [ 8] Pinned Mask

  // 00110 0 [12] Starts Humongous

  // 00110 1 [13] Continues Humongous

  //

  // 01000 0 [16] Old Mask

  //

  // 10000 0 [32] Archive Mask

  // 11100 0 [56] Open Archive

  // 11100 1 [57] Closed Archive

  //

  typedef enum {

    FreeTag               = 0,

    YoungMask             = 2,

    EdenTag               = YoungMask,

    SurvTag               = YoungMask + 1,

    HumongousMask         = 4,

    PinnedMask            = 8,

    StartsHumongousTag    = HumongousMask | PinnedMask,

    ContinuesHumongousTag = HumongousMask | PinnedMask + 1,

    OldMask               = 16,

    OldTag                = OldMask,

    // Archive regions are regions with immutable content (i.e. not reclaimed, and

    // not allocated into during regular operation). They differ in the kind of references

    // allowed for the contained objects:

    // - Closed archive regions form a separate self-contained (closed) object graph

    // within the set of all of these regions. No references outside of closed

    // archive regions are allowed.

    // - Open archive regions have no restrictions on the references of their objects.

    // Objects within these regions are allowed to have references to objects

    // contained in any other kind of regions.

    ArchiveMask           = 32,

    OpenArchiveTag        = ArchiveMask | PinnedMask | OldMask,

    ClosedArchiveTag      = ArchiveMask | PinnedMask | OldMask + 1

  } Tag;

  volatile Tag _tag;

  static bool is_valid(Tag tag);

  Tag get() const {

    hrt_assert_is_valid(_tag);

    return _tag;

  }

  // Sets the type to 'tag'.

  void set(Tag tag) {

    hrt_assert_is_valid(tag);

    hrt_assert_is_valid(_tag);

    _tag = tag;

  }

  // Sets the type to 'tag', expecting the type to be 'before'. This

  // is available for when we want to add sanity checking to the type

  // transition.

  void set_from(Tag tag, Tag before) {

    hrt_assert_is_valid(tag);

    hrt_assert_is_valid(before);

    hrt_assert_is_valid(_tag);

    assert(_tag == before, "HR tag: %u, expected: %u new tag; %u", _tag, before, tag);

    _tag = tag;

  }

public:

  // Queries

  bool is_free() const { return get() == FreeTag; }

  bool is_young()    const { return (get() & YoungMask) != 0; }

  bool is_eden()     const { return get() == EdenTag;  }

  bool is_survivor() const { return get() == SurvTag;  }

  bool is_humongous()           const { return (get() & HumongousMask) != 0;   }

  bool is_starts_humongous()    const { return get() == StartsHumongousTag;    }

  bool is_continues_humongous() const { return get() == ContinuesHumongousTag; }

  bool is_archive()        const { return (get() & ArchiveMask) != 0; }

  bool is_open_archive()   const { return get() == OpenArchiveTag; }

  bool is_closed_archive() const { return get() == ClosedArchiveTag; }

  // is_old regions may or may not also be pinned

  bool is_old() const { return (get() & OldMask) != 0; }

  bool is_old_or_humongous() const { return (get() & (OldMask | HumongousMask)) != 0; }

  // is_pinned regions may be archive or humongous

  bool is_pinned() const { return (get() & PinnedMask) != 0; }

  // Setters

  void set_free() { set(FreeTag); }

  void set_eden()        { set_from(EdenTag, FreeTag); }

  void set_eden_pre_gc() { set_from(EdenTag, SurvTag); }

  void set_survivor()    { set_from(SurvTag, FreeTag); }

  void set_starts_humongous()    { set_from(StartsHumongousTag,    FreeTag); }

  void set_continues_humongous() { set_from(ContinuesHumongousTag, FreeTag); }

  void set_old() { set(OldTag); }

  // Change the current region type to be of an old region type if not already done so.

  // Returns whether the region type has been changed or not.

  bool relabel_as_old() {

    //assert(!is_free(), "Should not try to move Free region");

    assert(!is_humongous(), "Should not try to move Humongous region");

    if (is_old()) {

      return false;

    }

    if (is_eden()) {

      set_from(OldTag, EdenTag);

      return true;

    } else if (is_free()) {

      set_from(OldTag, FreeTag);

      return true;

    } else {

      set_from(OldTag, SurvTag);

      return true;

    }

  }

  void set_open_archive()   { set_from(OpenArchiveTag, FreeTag); }

  void set_closed_archive() { set_from(ClosedArchiveTag, FreeTag); }

  // Misc

  const char* get_str() const;

  const char* get_short_str() const;

  G1HeapRegionTraceType::Type get_trace_type();

  HeapRegionType() : _tag(FreeTag) { hrt_assert_is_valid(_tag); }

};

#endif // SHARE_VM_GC_G1_HEAPREGIONTYPE_HPP