1 /*

     2  * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved.

     3  *

     4  * This code is free software; you can redistribute it and/or modify it

     5  * under the terms of the GNU General Public License version 2 only, as

     6  * published by the Free Software Foundation.

     7  *

     8  * This code is distributed in the hope that it will be useful, but WITHOUT

     9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

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

    11  * version 2 for more details (a copy is included in the LICENSE file that

    12  * accompanied this code).

    13  *

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

    15  * 2 along with this work; if not, write to the Free Software Foundation,

    16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    17  *

    18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    19  * or visit www.oracle.com if you need additional information or have any

    20  * questions.

    21  *

    22  */

    23 

    24 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSETCLONE_INLINE_HPP

    25 #define SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSETCLONE_INLINE_HPP

    26 

    27 #include "gc/shenandoah/shenandoahBarrierSet.inline.hpp"

    28 #include "gc/shenandoah/shenandoahCollectionSet.inline.hpp"

    29 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp"

    30 #include "gc/shenandoah/shenandoahHeap.inline.hpp"

    31 #include "memory/iterator.hpp"

    32 #include "oops/access.hpp"

    33 #include "oops/compressedOops.hpp"

    34 

    35 template <bool EVAC, bool ENQUEUE>

    36 class ShenandoahUpdateRefsForOopClosure: public BasicOopIterateClosure {

    37 private:

    38   ShenandoahHeap* const _heap;

    39   ShenandoahBarrierSet* const _bs;

    40   const ShenandoahCollectionSet* const _cset;

    41   Thread* const _thread;

    42 

    43   template <class T>

    44   inline void do_oop_work(T* p) {

    45     T o = RawAccess<>::oop_load(p);

    46     if (!CompressedOops::is_null(o)) {

    47       oop obj = CompressedOops::decode_not_null(o);

    48       if (_cset->is_in((HeapWord *)obj)) {

    49         oop fwd = _bs->resolve_forwarded_not_null(obj);

    50         if (EVAC && obj == fwd) {

    51           fwd = _heap->evacuate_object(obj, _thread);

    52         }

    53         if (ENQUEUE) {

    54           _bs->enqueue(fwd);

    55         }

    56         assert(obj != fwd || _heap->cancelled_gc(), "must be forwarded");

    57         ShenandoahHeap::cas_oop(fwd, p, o);

    58       }

    59 

    60     }

    61   }

    62 public:

    63   ShenandoahUpdateRefsForOopClosure() :

    64           _heap(ShenandoahHeap::heap()),

    65           _bs(ShenandoahBarrierSet::barrier_set()),

    66           _cset(_heap->collection_set()),

    67           _thread(Thread::current()) {

    68   }

    69 

    70   virtual void do_oop(oop* p)       { do_oop_work(p); }

    71   virtual void do_oop(narrowOop* p) { do_oop_work(p); }

    72 };

    73 

    74 void ShenandoahBarrierSet::clone_barrier(oop obj) {

    75   assert(ShenandoahCloneBarrier, "only get here with clone barriers enabled");

    76   if (!_heap->has_forwarded_objects()) return;

    77 

    78   // This is called for cloning an object (see jvm.cpp) after the clone

    79   // has been made. We are not interested in any 'previous value' because

    80   // it would be NULL in any case. But we *are* interested in any oop*

    81   // that potentially need to be updated.

    82 

    83   shenandoah_assert_correct(NULL, obj);

    84   if (_heap->is_evacuation_in_progress()) {

    85     ShenandoahEvacOOMScope evac_scope;

    86     ShenandoahUpdateRefsForOopClosure</* evac = */ true, /* enqueue */ false> cl;

    87     obj->oop_iterate(&cl);

    88   } else if (_heap->is_concurrent_traversal_in_progress()) {

    89     ShenandoahEvacOOMScope evac_scope;

    90     ShenandoahUpdateRefsForOopClosure</* evac = */ true, /* enqueue */ true> cl;

    91     obj->oop_iterate(&cl);

    92   } else {

    93     ShenandoahUpdateRefsForOopClosure</* evac = */ false, /* enqueue */ false> cl;

    94     obj->oop_iterate(&cl);

    95   }

    96 }

    97 

    98 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSETCLONE_INLINE_HPP