1 /*
   2  * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 #ifndef SHARE_GC_Z_ZOOPCLOSURES_INLINE_HPP
  25 #define SHARE_GC_Z_ZOOPCLOSURES_INLINE_HPP
  26 
  27 #include "classfile/classLoaderData.hpp"
  28 #include "gc/z/zBarrier.inline.hpp"
  29 #include "gc/z/zHeap.inline.hpp"
  30 #include "gc/z/zOop.inline.hpp"
  31 #include "gc/z/zOopClosures.hpp"
  32 #include "oops/oop.inline.hpp"
  33 #include "runtime/atomic.hpp"
  34 #include "utilities/debug.hpp"
  35 
  36 inline void ZLoadBarrierOopClosure::do_oop(oop* p) {
  37   ZBarrier::load_barrier_on_oop_field(p);
  38 }
  39 
  40 inline void ZLoadBarrierOopClosure::do_oop(narrowOop* p) {
  41   ShouldNotReachHere();
  42 }
  43 
  44 inline void ZNMethodOopClosure::do_oop(oop* p) {
  45   if (ZResurrection::is_blocked()) {
  46     ZBarrier::keep_alive_barrier_on_phantom_root_oop_field(p);
  47   } else {
  48     ZBarrier::load_barrier_on_root_oop_field(p);
  49   }
  50 }
  51 
  52 inline void ZNMethodOopClosure::do_oop(narrowOop* p) {
  53   ShouldNotReachHere();
  54 }
  55 
  56 template <bool finalizable>
  57 inline ZMarkBarrierOopClosure<finalizable>::ZMarkBarrierOopClosure() :
  58     ClaimMetadataVisitingOopIterateClosure(finalizable
  59                                                ? ClassLoaderData::_claim_finalizable
  60                                                : ClassLoaderData::_claim_strong,
  61                                            finalizable
  62                                                ? NULL
  63                                                : ZHeap::heap()->reference_discoverer()) {}
  64 
  65 template <bool finalizable>
  66 inline void ZMarkBarrierOopClosure<finalizable>::do_oop(oop* p) {
  67   ZBarrier::mark_barrier_on_oop_field(p, finalizable);
  68 }
  69 
  70 template <bool finalizable>
  71 inline void ZMarkBarrierOopClosure<finalizable>::do_oop(narrowOop* p) {
  72   ShouldNotReachHere();
  73 }
  74 
  75 inline bool ZPhantomIsAliveObjectClosure::do_object_b(oop o) {
  76   return ZBarrier::is_alive_barrier_on_phantom_oop(o);
  77 }
  78 
  79 inline void ZPhantomKeepAliveOopClosure::do_oop(oop* p) {
  80   ZBarrier::keep_alive_barrier_on_phantom_oop_field(p);
  81 }
  82 
  83 inline void ZPhantomKeepAliveOopClosure::do_oop(narrowOop* p) {
  84   ShouldNotReachHere();
  85 }
  86 
  87 inline void ZPhantomCleanOopClosure::do_oop(oop* p) {
  88   // Read the oop once, to make sure the liveness check
  89   // and the later clearing uses the same value.
  90   const oop obj = *(volatile oop*)p;
  91   if (ZBarrier::is_alive_barrier_on_phantom_oop(obj)) {
  92     ZBarrier::keep_alive_barrier_on_phantom_oop_field(p);
  93   } else {
  94     // The destination could have been modified/reused, in which case
  95     // we don't want to clear it. However, no one could write the same
  96     // oop here again (the object would be strongly live and we would
  97     // not consider clearing such oops), so therefore we don't have an
  98     // ABA problem here.
  99     Atomic::cmpxchg(oop(NULL), p, obj);
 100   }
 101 }
 102 
 103 inline void ZPhantomCleanOopClosure::do_oop(narrowOop* p) {
 104   ShouldNotReachHere();
 105 }
 106 
 107 #endif // SHARE_GC_Z_ZOOPCLOSURES_INLINE_HPP