1/* 2 * Copyright (c) 2001, 2015, 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 25#ifndef SHARE_VM_GC_SERIAL_DEFNEWGENERATION_INLINE_HPP 26#define SHARE_VM_GC_SERIAL_DEFNEWGENERATION_INLINE_HPP 27 28#include "gc/serial/defNewGeneration.hpp" 29#include "gc/shared/cardTableRS.hpp" 30#include "gc/shared/genCollectedHeap.hpp" 31#include "gc/shared/genOopClosures.inline.hpp" 32#include "gc/shared/space.hpp" 33 34// Methods of protected closure types 35 36template <class T> 37inline void DefNewGeneration::KeepAliveClosure::do_oop_work(T* p) { 38#ifdef ASSERT 39 { 40 // We never expect to see a null reference being processed 41 // as a weak reference. 42 assert (!oopDesc::is_null(*p), "expected non-null ref"); 43 oop obj = oopDesc::load_decode_heap_oop_not_null(p); 44 assert (obj->is_oop(), "expected an oop while scanning weak refs"); 45 } 46#endif // ASSERT 47 48 _cl->do_oop_nv(p); 49 50 // Card marking is trickier for weak refs. 51 // This oop is a 'next' field which was filled in while we 52 // were discovering weak references. While we might not need 53 // to take a special action to keep this reference alive, we 54 // will need to dirty a card as the field was modified. 55 // 56 // Alternatively, we could create a method which iterates through 57 // each generation, allowing them in turn to examine the modified 58 // field. 59 // 60 // We could check that p is also in the old generation, but 61 // dirty cards in the young gen are never scanned, so the 62 // extra check probably isn't worthwhile. 63 if (GenCollectedHeap::heap()->is_in_reserved(p)) { 64 oop obj = oopDesc::load_decode_heap_oop_not_null(p); 65 _rs->inline_write_ref_field_gc(p, obj); 66 } 67} 68 69template <class T> 70inline void DefNewGeneration::FastKeepAliveClosure::do_oop_work(T* p) { 71#ifdef ASSERT 72 { 73 // We never expect to see a null reference being processed 74 // as a weak reference. 75 assert (!oopDesc::is_null(*p), "expected non-null ref"); 76 oop obj = oopDesc::load_decode_heap_oop_not_null(p); 77 assert (obj->is_oop(), "expected an oop while scanning weak refs"); 78 } 79#endif // ASSERT 80 81 _cl->do_oop_nv(p); 82 83 // Optimized for Defnew generation if it's the youngest generation: 84 // we set a younger_gen card if we have an older->youngest 85 // generation pointer. 86 oop obj = oopDesc::load_decode_heap_oop_not_null(p); 87 if (((HeapWord*)obj < _boundary) && GenCollectedHeap::heap()->is_in_reserved(p)) { 88 _rs->inline_write_ref_field_gc(p, obj); 89 } 90} 91 92#endif // SHARE_VM_GC_SERIAL_DEFNEWGENERATION_INLINE_HPP 93