| /* |
| * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. |
| * 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 |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_GC_SHARED_CARDTABLEBARRIERSET_HPP |
| #define SHARE_VM_GC_SHARED_CARDTABLEBARRIERSET_HPP |
| |
| #include "gc/shared/modRefBarrierSet.hpp" |
| #include "utilities/align.hpp" |
| |
| class CardTable; |
| |
| // This kind of "BarrierSet" allows a "CollectedHeap" to detect and |
| // enumerate ref fields that have been modified (since the last |
| // enumeration.) |
| |
| // As it currently stands, this barrier is *imprecise*: when a ref field in |
| // an object "o" is modified, the card table entry for the card containing |
| // the head of "o" is dirtied, not necessarily the card containing the |
| // modified field itself. For object arrays, however, the barrier *is* |
| // precise; only the card containing the modified element is dirtied. |
| // Closures used to scan dirty cards should take these |
| // considerations into account. |
| |
| class CardTableBarrierSet: public ModRefBarrierSet { |
| // Some classes get to look at some private stuff. |
| friend class VMStructs; |
| protected: |
| |
| // Used in support of ReduceInitialCardMarks; only consulted if COMPILER2 |
| // or INCLUDE_JVMCI is being used |
| bool _defer_initial_card_mark; |
| CardTable* _card_table; |
| |
| CardTableBarrierSet(BarrierSetAssembler* barrier_set_assembler, |
| BarrierSetC1* barrier_set_c1, |
| BarrierSetC2* barrier_set_c2, |
| CardTable* card_table, |
| const BarrierSet::FakeRtti& fake_rtti); |
| |
| public: |
| CardTableBarrierSet(CardTable* card_table); |
| ~CardTableBarrierSet(); |
| |
| CardTable* card_table() const { return _card_table; } |
| |
| virtual void initialize(); |
| |
| void write_region(MemRegion mr) { |
| invalidate(mr); |
| } |
| |
| void write_ref_array_work(MemRegion mr); |
| |
| public: |
| // Record a reference update. Note that these versions are precise! |
| // The scanning code has to handle the fact that the write barrier may be |
| // either precise or imprecise. We make non-virtual inline variants of |
| // these functions here for performance. |
| template <DecoratorSet decorators, typename T> |
| void write_ref_field_post(T* field, oop newVal); |
| |
| virtual void invalidate(MemRegion mr); |
| |
| // ReduceInitialCardMarks |
| void initialize_deferred_card_mark_barriers(); |
| |
| // If the CollectedHeap was asked to defer a store barrier above, |
| // this informs it to flush such a deferred store barrier to the |
| // remembered set. |
| void flush_deferred_card_mark_barrier(JavaThread* thread); |
| |
| // If a compiler is eliding store barriers for TLAB-allocated objects, |
| // we will be informed of a slow-path allocation by a call |
| // to on_slowpath_allocation_exit() below. Such a call precedes the |
| // initialization of the object itself, and no post-store-barriers will |
| // be issued. Some heap types require that the barrier strictly follows |
| // the initializing stores. (This is currently implemented by deferring the |
| // barrier until the next slow-path allocation or gc-related safepoint.) |
| // This interface answers whether a particular barrier type needs the card |
| // mark to be thus strictly sequenced after the stores. |
| virtual bool card_mark_must_follow_store() const; |
| |
| virtual void on_slowpath_allocation_exit(JavaThread* thread, oop new_obj); |
| virtual void on_thread_detach(JavaThread* thread); |
| |
| virtual void make_parsable(JavaThread* thread) { flush_deferred_card_mark_barrier(thread); } |
| |
| virtual void print_on(outputStream* st) const; |
| |
| template <DecoratorSet decorators, typename BarrierSetT = CardTableBarrierSet> |
| class AccessBarrier: public ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> {}; |
| }; |
| |
| template<> |
| struct BarrierSet::GetName<CardTableBarrierSet> { |
| static const BarrierSet::Name value = BarrierSet::CardTableBarrierSet; |
| }; |
| |
| template<> |
| struct BarrierSet::GetType<BarrierSet::CardTableBarrierSet> { |
| typedef ::CardTableBarrierSet type; |
| }; |
| |
| #endif // SHARE_VM_GC_SHARED_CARDTABLEBARRIERSET_HPP |