/*

 * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

/////////////////////////////////////////////////////////////////

// Closures used by ConcurrentMarkSweepGeneration's collector

/////////////////////////////////////////////////////////////////

class ConcurrentMarkSweepGeneration;

class CMSBitMap;

class CMSMarkStack;

class CMSCollector;

class MarkFromRootsClosure;

class Par_MarkFromRootsClosure;

// Decode the oop and call do_oop on it.

#define DO_OOP_WORK_DEFN \

  void do_oop(oop obj);                                   \

  template <class T> inline void do_oop_work(T* p) {      \

    T heap_oop = oopDesc::load_heap_oop(p);               \

    if (!oopDesc::is_null(heap_oop)) {                    \

      oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);       \

      do_oop(obj);                                        \

    }                                                     \

  }

class MarkRefsIntoClosure: public OopsInGenClosure {

 private:

  const MemRegion _span;

  CMSBitMap*      _bitMap;

 protected:

  DO_OOP_WORK_DEFN

 public:

  MarkRefsIntoClosure(MemRegion span, CMSBitMap* bitMap);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { MarkRefsIntoClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { MarkRefsIntoClosure::do_oop_work(p); }

  bool do_header() { return true; }

  Prefetch::style prefetch_style() {

    return Prefetch::do_read;

  }

};

// A variant of the above used in certain kinds of CMS

// marking verification.

class MarkRefsIntoVerifyClosure: public OopsInGenClosure {

 private:

  const MemRegion _span;

  CMSBitMap*      _verification_bm;

  CMSBitMap*      _cms_bm;

 protected:

  DO_OOP_WORK_DEFN

 public:

  MarkRefsIntoVerifyClosure(MemRegion span, CMSBitMap* verification_bm,

                            CMSBitMap* cms_bm);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { MarkRefsIntoVerifyClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { MarkRefsIntoVerifyClosure::do_oop_work(p); }

  bool do_header() { return true; }

  Prefetch::style prefetch_style() {

    return Prefetch::do_read;

  }

};

// KlassRememberingOopClosure is used when marking of the permanent generation

// is being done.  It adds fields to support revisiting of klasses

// for class unloading.  _should_remember_klasses should be set to

// indicate if klasses should be remembered.  Currently that is whenever

// CMS class unloading is turned on.  The _revisit_stack is used

// to save the klasses for later processing.

class KlassRememberingOopClosure : public OopClosure {

 protected:

  CMSCollector* _collector;

  CMSMarkStack* _revisit_stack;

  bool const    _should_remember_klasses;

 public:

  void check_remember_klasses() const PRODUCT_RETURN;

  virtual const bool should_remember_klasses() const {

    check_remember_klasses();

    return _should_remember_klasses;

  }

  virtual void remember_klass(Klass* k);

  KlassRememberingOopClosure(CMSCollector* collector,

                             ReferenceProcessor* rp,

                             CMSMarkStack* revisit_stack);

};

// Similar to KlassRememberingOopClosure for use when multiple

// GC threads will execute the closure.

class Par_KlassRememberingOopClosure : public KlassRememberingOopClosure {

 public:

  Par_KlassRememberingOopClosure(CMSCollector* collector,

                                 ReferenceProcessor* rp,

                                 CMSMarkStack* revisit_stack):

    KlassRememberingOopClosure(collector, rp, revisit_stack) {}

  virtual void remember_klass(Klass* k);

};

// The non-parallel version (the parallel version appears further below).

class PushAndMarkClosure: public KlassRememberingOopClosure {

 private:

  MemRegion     _span;

  CMSBitMap*    _bit_map;

  CMSBitMap*    _mod_union_table;

  CMSMarkStack* _mark_stack;

  bool          _concurrent_precleaning;

 protected:

  DO_OOP_WORK_DEFN

 public:

  PushAndMarkClosure(CMSCollector* collector,

                     MemRegion span,

                     ReferenceProcessor* rp,

                     CMSBitMap* bit_map,

                     CMSBitMap* mod_union_table,

                     CMSMarkStack* mark_stack,

                     CMSMarkStack* revisit_stack,

                     bool concurrent_precleaning);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { PushAndMarkClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { PushAndMarkClosure::do_oop_work(p); }

  bool do_header() { return true; }

  Prefetch::style prefetch_style() {

    return Prefetch::do_read;

  }

  // In support of class unloading

  virtual const bool should_remember_mdo() const {

    return false;

    // return _should_remember_klasses;

  }

  virtual void remember_mdo(DataLayout* v);

};

// In the parallel case, the revisit stack, the bit map and the

// reference processor are currently all shared. Access to

// these shared mutable structures must use appropriate

// synchronization (for instance, via CAS). The marking stack

// used in the non-parallel case above is here replaced with

// an OopTaskQueue structure to allow efficient work stealing.

class Par_PushAndMarkClosure: public Par_KlassRememberingOopClosure {

 private:

  MemRegion     _span;

  CMSBitMap*    _bit_map;

  OopTaskQueue* _work_queue;

 protected:

  DO_OOP_WORK_DEFN

 public:

  Par_PushAndMarkClosure(CMSCollector* collector,

                         MemRegion span,

                         ReferenceProcessor* rp,

                         CMSBitMap* bit_map,

                         OopTaskQueue* work_queue,

                         CMSMarkStack* revisit_stack);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { Par_PushAndMarkClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { Par_PushAndMarkClosure::do_oop_work(p); }

  bool do_header() { return true; }

  Prefetch::style prefetch_style() {

    return Prefetch::do_read;

  }

  // In support of class unloading

  virtual const bool should_remember_mdo() const {

    return false;

    // return _should_remember_klasses;

  }

  virtual void remember_mdo(DataLayout* v);

};

// The non-parallel version (the parallel version appears further below).

class MarkRefsIntoAndScanClosure: public OopsInGenClosure {

 private:

  MemRegion          _span;

  CMSBitMap*         _bit_map;

  CMSMarkStack*      _mark_stack;

  PushAndMarkClosure _pushAndMarkClosure;

  CMSCollector*      _collector;

  Mutex*             _freelistLock;

  bool               _yield;

  // Whether closure is being used for concurrent precleaning

  bool               _concurrent_precleaning;

 protected:

  DO_OOP_WORK_DEFN

 public:

  MarkRefsIntoAndScanClosure(MemRegion span,

                             ReferenceProcessor* rp,

                             CMSBitMap* bit_map,

                             CMSBitMap* mod_union_table,

                             CMSMarkStack* mark_stack,

                             CMSMarkStack* revisit_stack,

                             CMSCollector* collector,

                             bool should_yield,

                             bool concurrent_precleaning);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { MarkRefsIntoAndScanClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { MarkRefsIntoAndScanClosure::do_oop_work(p); }

  bool do_header() { return true; }

  Prefetch::style prefetch_style() {

    return Prefetch::do_read;

  }

  void set_freelistLock(Mutex* m) {

    _freelistLock = m;

  }

  virtual const bool should_remember_klasses() const {

    return _pushAndMarkClosure.should_remember_klasses();

  }

  virtual void remember_klass(Klass* k) {

    _pushAndMarkClosure.remember_klass(k);

  }

 private:

  inline void do_yield_check();

  void do_yield_work();

  bool take_from_overflow_list();

};

// Tn this, the parallel avatar of MarkRefsIntoAndScanClosure, the revisit

// stack and the bitMap are shared, so access needs to be suitably

// sycnhronized. An OopTaskQueue structure, supporting efficient

// workstealing, replaces a CMSMarkStack for storing grey objects.

class Par_MarkRefsIntoAndScanClosure: public OopsInGenClosure {

 private:

  MemRegion              _span;

  CMSBitMap*             _bit_map;

  OopTaskQueue*          _work_queue;

  const uint             _low_water_mark;

  Par_PushAndMarkClosure _par_pushAndMarkClosure;

 protected:

  DO_OOP_WORK_DEFN

 public:

  Par_MarkRefsIntoAndScanClosure(CMSCollector* collector,

                                 MemRegion span,

                                 ReferenceProcessor* rp,

                                 CMSBitMap* bit_map,

                                 OopTaskQueue* work_queue,

                                 CMSMarkStack*  revisit_stack);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { Par_MarkRefsIntoAndScanClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { Par_MarkRefsIntoAndScanClosure::do_oop_work(p); }

  bool do_header() { return true; }

  // When ScanMarkedObjectsAgainClosure is used,

  // it passes [Par_]MarkRefsIntoAndScanClosure to oop_oop_iterate(),

  // and this delegation is used.

  virtual const bool should_remember_klasses() const {

    return _par_pushAndMarkClosure.should_remember_klasses();

  }

  // See comment on should_remember_klasses() above.

  virtual void remember_klass(Klass* k) {

    _par_pushAndMarkClosure.remember_klass(k);

  }

  Prefetch::style prefetch_style() {

    return Prefetch::do_read;

  }

  void trim_queue(uint size);

};

// This closure is used during the concurrent marking phase

// following the first checkpoint. Its use is buried in

// the closure MarkFromRootsClosure.

class PushOrMarkClosure: public KlassRememberingOopClosure {

 private:

  MemRegion       _span;

  CMSBitMap*      _bitMap;

  CMSMarkStack*   _markStack;

  HeapWord* const _finger;

  MarkFromRootsClosure* const

                  _parent;

 protected:

  DO_OOP_WORK_DEFN

 public:

  PushOrMarkClosure(CMSCollector* cms_collector,

                    MemRegion span,

                    CMSBitMap* bitMap,

                    CMSMarkStack* markStack,

                    CMSMarkStack* revisitStack,

                    HeapWord* finger,

                    MarkFromRootsClosure* parent);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { PushOrMarkClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { PushOrMarkClosure::do_oop_work(p); }

  // In support of class unloading

  virtual const bool should_remember_mdo() const {

    return false;

    // return _should_remember_klasses;

  }

  virtual void remember_mdo(DataLayout* v);

  // Deal with a stack overflow condition

  void handle_stack_overflow(HeapWord* lost);

 private:

  inline void do_yield_check();

};

// A parallel (MT) version of the above.

// This closure is used during the concurrent marking phase

// following the first checkpoint. Its use is buried in

// the closure Par_MarkFromRootsClosure.

class Par_PushOrMarkClosure: public Par_KlassRememberingOopClosure {

 private:

  MemRegion        _whole_span;

  MemRegion        _span;        // local chunk

  CMSBitMap*       _bit_map;

  OopTaskQueue*    _work_queue;

  CMSMarkStack*    _overflow_stack;

  HeapWord*  const _finger;

  HeapWord** const _global_finger_addr;

  Par_MarkFromRootsClosure* const

                   _parent;

 protected:

  DO_OOP_WORK_DEFN

 public:

  Par_PushOrMarkClosure(CMSCollector* cms_collector,

                        MemRegion span,

                        CMSBitMap* bit_map,

                        OopTaskQueue* work_queue,

                        CMSMarkStack* mark_stack,

                        CMSMarkStack* revisit_stack,

                        HeapWord* finger,

                        HeapWord** global_finger_addr,

                        Par_MarkFromRootsClosure* parent);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { Par_PushOrMarkClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { Par_PushOrMarkClosure::do_oop_work(p); }

  // In support of class unloading

  virtual const bool should_remember_mdo() const {

    return false;

    // return _should_remember_klasses;

  }

  virtual void remember_mdo(DataLayout* v);

  // Deal with a stack overflow condition

  void handle_stack_overflow(HeapWord* lost);

 private:

  inline void do_yield_check();

};

// For objects in CMS generation, this closure marks

// given objects (transitively) as being reachable/live.

// This is currently used during the (weak) reference object

// processing phase of the CMS final checkpoint step, as

// well as during the concurrent precleaning of the discovered

// reference lists.

class CMSKeepAliveClosure: public KlassRememberingOopClosure {

 private:

  const MemRegion _span;

  CMSMarkStack* _mark_stack;

  CMSBitMap*    _bit_map;

  bool          _concurrent_precleaning;

 protected:

  DO_OOP_WORK_DEFN

 public:

  CMSKeepAliveClosure(CMSCollector* collector, MemRegion span,

                      CMSBitMap* bit_map, CMSMarkStack* mark_stack,

                      CMSMarkStack* revisit_stack, bool cpc);

  bool    concurrent_precleaning() const { return _concurrent_precleaning; }

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { CMSKeepAliveClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { CMSKeepAliveClosure::do_oop_work(p); }

};

class CMSInnerParMarkAndPushClosure: public Par_KlassRememberingOopClosure {

 private:

  MemRegion     _span;

  OopTaskQueue* _work_queue;

  CMSBitMap*    _bit_map;

 protected:

  DO_OOP_WORK_DEFN

 public:

  CMSInnerParMarkAndPushClosure(CMSCollector* collector,

                                MemRegion span, CMSBitMap* bit_map,

                                CMSMarkStack* revisit_stack,

                                OopTaskQueue* work_queue);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { CMSInnerParMarkAndPushClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { CMSInnerParMarkAndPushClosure::do_oop_work(p); }

};

// A parallel (MT) version of the above, used when

// reference processing is parallel; the only difference

// is in the do_oop method.

class CMSParKeepAliveClosure: public Par_KlassRememberingOopClosure {

 private:

  MemRegion     _span;

  OopTaskQueue* _work_queue;

  CMSBitMap*    _bit_map;

  CMSInnerParMarkAndPushClosure

                _mark_and_push;

  const uint    _low_water_mark;

  void trim_queue(uint max);

 protected:

  DO_OOP_WORK_DEFN

 public:

  CMSParKeepAliveClosure(CMSCollector* collector, MemRegion span,

                         CMSBitMap* bit_map, CMSMarkStack* revisit_stack,

                         OopTaskQueue* work_queue);

  virtual void do_oop(oop* p);

  virtual void do_oop(narrowOop* p);

  inline void do_oop_nv(oop* p)       { CMSParKeepAliveClosure::do_oop_work(p); }

  inline void do_oop_nv(narrowOop* p) { CMSParKeepAliveClosure::do_oop_work(p); }

};