1 /* 2 * Copyright (c) 1997, 2016, 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 #include "precompiled.hpp" 26 #include "classfile/javaClasses.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "oops/instanceRefKlass.inline.hpp" 29 #include "oops/oop.inline.hpp" 30 31 void InstanceRefKlass::update_nonstatic_oop_maps(Klass* k) { 32 // Clear the nonstatic oop-map entries corresponding to referent 33 // and nextPending field. They are treated specially by the 34 // garbage collector. 35 // The discovered field is used only by the garbage collector 36 // and is also treated specially. 37 InstanceKlass* ik = InstanceKlass::cast(k); 38 39 // Check that we have the right class 40 debug_only(static bool first_time = true); 41 assert(k == SystemDictionary::Reference_klass() && first_time, 42 "Invalid update of maps"); 43 debug_only(first_time = false); 44 assert(ik->nonstatic_oop_map_count() == 1, "just checking"); 45 46 OopMapBlock* map = ik->start_of_nonstatic_oop_maps(); 47 48 // Check that the current map is (2,4) - currently points at field with 49 // offset 2 (words) and has 4 map entries. 50 debug_only(int offset = java_lang_ref_Reference::referent_offset); 51 debug_only(unsigned int count = ((java_lang_ref_Reference::discovered_offset - 52 java_lang_ref_Reference::referent_offset)/heapOopSize) + 1); 53 54 if (UseSharedSpaces) { 55 assert(map->offset() == java_lang_ref_Reference::queue_offset && 56 map->count() == 1, "just checking"); 57 } else { 58 assert(map->offset() == offset && map->count() == count, 59 "just checking"); 60 61 // Update map to (3,1) - point to offset of 3 (words) with 1 map entry. 62 map->set_offset(java_lang_ref_Reference::queue_offset); 63 map->set_count(1); 64 } 65 } 66 67 68 // Verification 69 70 void InstanceRefKlass::oop_verify_on(oop obj, outputStream* st) { 71 InstanceKlass::oop_verify_on(obj, st); 72 // Verify referent field 73 oop referent = java_lang_ref_Reference::referent(obj); 74 if (referent != NULL) { 75 guarantee(referent->is_oop(), "referent field heap failed"); 76 } 77 // Verify next field 78 oop next = java_lang_ref_Reference::next(obj); 79 if (next != NULL) { 80 guarantee(next->is_oop(), "next field should be an oop"); 81 guarantee(next->is_instance(), "next field should be an instance"); 82 guarantee(InstanceKlass::cast(next->klass())->is_reference_instance_klass(), "next field verify failed"); 83 } 84 }