1 /*
  2  * Copyright (c) 2016, 2020, 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
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 24 
 25 #ifndef SHARE_GC_G1_G1BARRIERSET_INLINE_HPP
 26 #define SHARE_GC_G1_G1BARRIERSET_INLINE_HPP
 27 
 28 #include "gc/g1/g1BarrierSet.hpp"
 29 
 30 #include "gc/g1/g1CardTable.hpp"
 31 #include "gc/g1/g1CollectedHeap.inline.hpp"
 32 #include "gc/shared/accessBarrierSupport.inline.hpp"
 33 #include "oops/access.inline.hpp"
 34 #include "oops/compressedOops.inline.hpp"
 35 #include "oops/oop.hpp"
 36 
 37 template <DecoratorSet decorators, typename T>
 38 inline void G1BarrierSet::write_ref_field_pre(T* field) {
 39   if (HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value ||
 40       HasDecorator<decorators, AS_NO_KEEPALIVE>::value) {
 41     return;
 42   }
 43 
 44   T heap_oop = RawAccess<MO_RELAXED>::oop_load(field);
 45   if (!CompressedOops::is_null(heap_oop)) {
 46     enqueue(CompressedOops::decode_not_null(heap_oop));
 47   }
 48 }
 49 
 50 template <DecoratorSet decorators, typename T>
 51 inline void G1BarrierSet::write_ref_field_post(T* field, oop new_val) {
 52   volatile CardValue* byte = _card_table->byte_for(field);
 53   if (*byte != G1CardTable::g1_young_card_val()) {
 54     // Take a slow path for cards in old
 55     write_ref_field_post_slow(byte);
 56   }
 57 }
 58 
 59 inline void G1BarrierSet::enqueue_if_weak(DecoratorSet decorators, oop value) {
 60   assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Reference strength must be known");
 61   // Loading from a weak or phantom reference needs enqueueing, as
 62   // the object may not have been reachable (part of the snapshot)
 63   // when marking started.
 64   const bool on_strong_oop_ref = (decorators & ON_STRONG_OOP_REF) != 0;
 65   const bool peek              = (decorators & AS_NO_KEEPALIVE) != 0;
 66   const bool needs_enqueue     = (!peek && !on_strong_oop_ref);
 67 
 68   if (needs_enqueue && value != NULL) {
 69     enqueue(value);
 70   }
 71 }
 72 
 73 template <DecoratorSet decorators, typename BarrierSetT>
 74 template <typename T>
 75 inline oop G1BarrierSet::AccessBarrier<decorators, BarrierSetT>::
 76 oop_load_not_in_heap(T* addr) {
 77   oop value = ModRef::oop_load_not_in_heap(addr);
 78   enqueue_if_weak(decorators, value);
 79   return value;
 80 }
 81 
 82 template <DecoratorSet decorators, typename BarrierSetT>
 83 template <typename T>
 84 inline oop G1BarrierSet::AccessBarrier<decorators, BarrierSetT>::
 85 oop_load_in_heap(T* addr) {
 86   oop value = ModRef::oop_load_in_heap(addr);
 87   enqueue_if_weak(decorators, value);
 88   return value;
 89 }
 90 
 91 template <DecoratorSet decorators, typename BarrierSetT>
 92 inline oop G1BarrierSet::AccessBarrier<decorators, BarrierSetT>::
 93 oop_load_in_heap_at(oop base, ptrdiff_t offset) {
 94   oop value = ModRef::oop_load_in_heap_at(base, offset);
 95   enqueue_if_weak(AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset), value);
 96   return value;
 97 }
 98 
 99 template <DecoratorSet decorators, typename BarrierSetT>
100 template <typename T>
101 inline void G1BarrierSet::AccessBarrier<decorators, BarrierSetT>::
102 oop_store_not_in_heap(T* addr, oop new_value) {
103   // Apply SATB barriers for all non-heap references, to allow
104   // concurrent scanning of such references.
105   G1BarrierSet *bs = barrier_set_cast<G1BarrierSet>(BarrierSet::barrier_set());
106   bs->write_ref_field_pre<decorators>(addr);
107   Raw::oop_store(addr, new_value);
108 }
109 
110 inline bool G1BarrierSet::requires_barriers(oop obj) {
111   return G1CollectedHeap::heap()->G1CollectedHeap::requires_barriers(obj);
112 }
113 
114 #endif // SHARE_GC_G1_G1BARRIERSET_INLINE_HPP