gc_implementation/g1/g1OopClosures.hpp

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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_HPP

class HeapRegion;
class G1CollectedHeap;
class G1RemSet;
class ConcurrentMark;
class DirtyCardToOopClosure;
class CMBitMap;
class CMMarkStack;
class G1ParScanThreadState;
class CMTask;
class ReferenceProcessor;

// A class that scans oops in a given heap region (much as OopsInGenClosure
// scans oops in a generation.)
class OopsInHeapRegionClosure: public OopsInGenClosure {
protected:
  HeapRegion* _from;
public:
  void set_region(HeapRegion* from) { _from = from; }
};

class G1ParClosureSuper : public OopsInHeapRegionClosure {
protected:
  G1CollectedHeap* _g1;
  G1RemSet* _g1_rem;
  ConcurrentMark* _cm;
  G1ParScanThreadState* _par_scan_state;
  uint _worker_id;
  bool _during_initial_mark;
  bool _mark_in_progress;
public:
  G1ParClosureSuper(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state);
  bool apply_to_weak_ref_discovered_field() { return true; }
};

class G1ParPushHeapRSClosure : public G1ParClosureSuper {
public:
  G1ParPushHeapRSClosure(G1CollectedHeap* g1,
                         G1ParScanThreadState* par_scan_state):
    G1ParClosureSuper(g1, par_scan_state) { }

  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)          { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p)    { do_oop_nv(p); }
};

class G1ParScanClosure : public G1ParClosureSuper {
public:
  G1ParScanClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state, ReferenceProcessor* rp) :
    G1ParClosureSuper(g1, par_scan_state)
  {
    assert(_ref_processor == NULL, "sanity");
    _ref_processor = rp;
  }

  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)          { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p)    { do_oop_nv(p); }
};

#define G1_PARTIAL_ARRAY_MASK 0x2

template <class T> inline bool has_partial_array_mask(T* ref) {
  return ((uintptr_t)ref & G1_PARTIAL_ARRAY_MASK) == G1_PARTIAL_ARRAY_MASK;
}

template <class T> inline T* set_partial_array_mask(T obj) {
  assert(((uintptr_t)obj & G1_PARTIAL_ARRAY_MASK) == 0, "Information loss!");
  return (T*) ((uintptr_t)obj | G1_PARTIAL_ARRAY_MASK);
}

template <class T> inline oop clear_partial_array_mask(T* ref) {
  return oop((intptr_t)ref & ~G1_PARTIAL_ARRAY_MASK);
}

class G1ParScanPartialArrayClosure : public G1ParClosureSuper {
  G1ParScanClosure _scanner;

public:
  G1ParScanPartialArrayClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state, ReferenceProcessor* rp) :
    G1ParClosureSuper(g1, par_scan_state), _scanner(g1, par_scan_state, rp)
  {
    assert(_ref_processor == NULL, "sanity");
  }

  G1ParScanClosure* scanner() {
    return &_scanner;
  }

  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)       { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
};

template <bool do_gen_barrier, G1Barrier barrier, bool do_mark_object>
class G1ParCopyClosure : public G1ParClosureSuper {
  G1ParScanClosure _scanner;
  template <class T> void do_oop_work(T* p);

protected:
  // Mark the object if it's not already marked. This is used to mark
  // objects pointed to by roots that are guaranteed not to move
  // during the GC (i.e., non-CSet objects). It is MT-safe.
  void mark_object(oop obj);

  // Mark the object if it's not already marked. This is used to mark
  // objects pointed to by roots that have been forwarded during a
  // GC. It is MT-safe.
  void mark_forwarded_object(oop from_obj, oop to_obj);

  oop copy_to_survivor_space(oop obj);

public:
  G1ParCopyClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state,
                   ReferenceProcessor* rp) :
      _scanner(g1, par_scan_state, rp),
      G1ParClosureSuper(g1, par_scan_state) {
    assert(_ref_processor == NULL, "sanity");
  }

  G1ParScanClosure* scanner() { return &_scanner; }

  template <class T> void do_oop_nv(T* p) {
    do_oop_work(p);
  }
  virtual void do_oop(oop* p)       { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
};

typedef G1ParCopyClosure<false, G1BarrierNone, false> G1ParScanExtRootClosure;
typedef G1ParCopyClosure<true,  G1BarrierNone, false> G1ParScanPermClosure;

typedef G1ParCopyClosure<false, G1BarrierNone, true> G1ParScanAndMarkExtRootClosure;
typedef G1ParCopyClosure<true,  G1BarrierNone, true> G1ParScanAndMarkPermClosure;

// The following closure types are no longer used but are retained
// for historical reasons:
// typedef G1ParCopyClosure<false, G1BarrierRS,   false> G1ParScanHeapRSClosure;
// typedef G1ParCopyClosure<false, G1BarrierRS,   true> G1ParScanAndMarkHeapRSClosure;

// The following closure type is defined in g1_specialized_oop_closures.hpp:
//
// typedef G1ParCopyClosure<false, G1BarrierEvac, false> G1ParScanHeapEvacClosure;

// We use a separate closure to handle references during evacuation
// failure processing.
// We could have used another instance of G1ParScanHeapEvacClosure
// (since that closure no longer assumes that the references it
// handles point into the collection set).

typedef G1ParCopyClosure<false, G1BarrierEvac, false> G1ParScanHeapEvacFailureClosure;

class FilterIntoCSClosure: public OopClosure {
  G1CollectedHeap* _g1;
  OopClosure* _oc;
  DirtyCardToOopClosure* _dcto_cl;
public:
  FilterIntoCSClosure(  DirtyCardToOopClosure* dcto_cl,
                        G1CollectedHeap* g1,
                        OopClosure* oc) :
    _dcto_cl(dcto_cl), _g1(g1), _oc(oc) { }

  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)        { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p)  { do_oop_nv(p); }
  bool apply_to_weak_ref_discovered_field() { return true; }
  bool do_header() { return false; }
};

class FilterOutOfRegionClosure: public OopClosure {
  HeapWord* _r_bottom;
  HeapWord* _r_end;
  OopClosure* _oc;
public:
  FilterOutOfRegionClosure(HeapRegion* r, OopClosure* oc);
  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p) { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
  bool apply_to_weak_ref_discovered_field() { return true; }
  bool do_header() { return false; }
};

// Closure for iterating over object fields during concurrent marking
class G1CMOopClosure : public OopClosure {
private:
  G1CollectedHeap*   _g1h;
  ConcurrentMark*    _cm;
  CMTask*            _task;
public:
  G1CMOopClosure(G1CollectedHeap* g1h, ConcurrentMark* cm, CMTask* task);
  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(      oop* p) { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
};

// Closure to scan the root regions during concurrent marking
class G1RootRegionScanClosure : public OopClosure {
private:
  G1CollectedHeap* _g1h;
  ConcurrentMark*  _cm;
  uint _worker_id;
public:
  G1RootRegionScanClosure(G1CollectedHeap* g1h, ConcurrentMark* cm,
                          uint worker_id) :
    _g1h(g1h), _cm(cm), _worker_id(worker_id) { }
  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(      oop* p) { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
};

// Closure that applies the given two closures in sequence.
// Used by the RSet refinement code (when updating RSets
// during an evacuation pause) to record cards containing
// pointers into the collection set.

class G1Mux2Closure : public OopClosure {
  OopClosure* _c1;
  OopClosure* _c2;
public:
  G1Mux2Closure(OopClosure *c1, OopClosure *c2);
  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)        { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p)  { do_oop_nv(p); }
};

// A closure that returns true if it is actually applied
// to a reference

class G1TriggerClosure : public OopClosure {
  bool _triggered;
public:
  G1TriggerClosure();
  bool triggered() const { return _triggered; }
  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)        { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p)  { do_oop_nv(p); }
};

// A closure which uses a triggering closure to determine
// whether to apply an oop closure.

class G1InvokeIfNotTriggeredClosure: public OopClosure {
  G1TriggerClosure* _trigger_cl;
  OopClosure* _oop_cl;
public:
  G1InvokeIfNotTriggeredClosure(G1TriggerClosure* t, OopClosure* oc);
  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)        { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p)  { do_oop_nv(p); }
};

class G1UpdateRSOrPushRefOopClosure: public OopClosure {
  G1CollectedHeap* _g1;
  G1RemSet* _g1_rem_set;
  HeapRegion* _from;
  OopsInHeapRegionClosure* _push_ref_cl;
  bool _record_refs_into_cset;
  int _worker_i;

public:
  G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h,
                                G1RemSet* rs,
                                OopsInHeapRegionClosure* push_ref_cl,
                                bool record_refs_into_cset,
                                int worker_i = 0);

  void set_from(HeapRegion* from) {
    assert(from != NULL, "from region must be non-NULL");
    _from = from;
  }

  bool self_forwarded(oop obj) {
    bool result = (obj->is_forwarded() && (obj->forwardee()== obj));
    return result;
  }

  bool apply_to_weak_ref_discovered_field() { return true; }

  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
  virtual void do_oop(oop* p)       { do_oop_nv(p); }
};

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_HPP