1 /* 2 * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates. 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 HOTSPOT_EPSILONBARRIERSET_HPP_H 25 #define HOTSPOT_EPSILONBARRIERSET_HPP_H 26 27 #include "gc/shared/collectorPolicy.hpp" 28 #include "gc/shared/barrierSet.hpp" 29 30 // Most are no-ops. 31 class EpsilonBarrierSet: public ModRefBarrierSet { 32 friend class VMStructs; 33 34 public: 35 EpsilonBarrierSet() : 36 ModRefBarrierSet(BarrierSet::FakeRtti(BarrierSet::Epsilon)) {}; 37 38 virtual bool has_write_ref_barrier() { return false; } 39 virtual bool has_write_ref_pre_barrier() { return false; } 40 virtual bool has_write_ref_array_opt() { return true; } // TODO: why? 41 virtual bool has_write_region_opt() { return true; } // TODO: why? 42 43 virtual bool is_aligned(HeapWord *addr) { return true; } // TODO: Safe? 44 45 virtual void resize_covered_region(MemRegion new_region) {} 46 virtual void print_on(outputStream *st) const {} 47 48 protected: 49 virtual void write_ref_field_work(void *field, oop new_val, bool release) {} 50 virtual void write_ref_array_work(MemRegion mr) {} 51 virtual void write_region_work(MemRegion mr) {} 52 53 public: 54 virtual void invalidate(MemRegion mr) {} 55 virtual void clear(MemRegion mr) {} 56 }; 57 58 template<> 59 struct BarrierSet::GetName<EpsilonBarrierSet> { 60 static const BarrierSet::Name value = BarrierSet::Epsilon; 61 }; 62 63 #endif