1/* 2 * Copyright (c) 2006, 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#ifndef SHARE_VM_OOPS_MARKOOP_INLINE_HPP 26#define SHARE_VM_OOPS_MARKOOP_INLINE_HPP 27 28#include "oops/klass.hpp" 29#include "oops/markOop.hpp" 30#include "oops/oop.inline.hpp" 31#include "runtime/globals.hpp" 32 33// Should this header be preserved during GC (when biased locking is enabled)? 34inline bool markOopDesc::must_be_preserved_with_bias(oop obj_containing_mark) const { 35 assert(UseBiasedLocking, "unexpected"); 36 if (has_bias_pattern()) { 37 // Will reset bias at end of collection 38 // Mark words of biased and currently locked objects are preserved separately 39 return false; 40 } 41 markOop prototype_header = prototype_for_object(obj_containing_mark); 42 if (prototype_header->has_bias_pattern()) { 43 // Individual instance which has its bias revoked; must return 44 // true for correctness 45 return true; 46 } 47 return (!is_unlocked() || !has_no_hash()); 48} 49 50// Should this header be preserved during GC? 51inline bool markOopDesc::must_be_preserved(oop obj_containing_mark) const { 52 if (!UseBiasedLocking) 53 return (!is_unlocked() || !has_no_hash()); 54 return must_be_preserved_with_bias(obj_containing_mark); 55} 56 57// Should this header be preserved in the case of a promotion failure 58// during scavenge (when biased locking is enabled)? 59inline bool markOopDesc::must_be_preserved_with_bias_for_promotion_failure(oop obj_containing_mark) const { 60 assert(UseBiasedLocking, "unexpected"); 61 // We don't explicitly save off the mark words of biased and 62 // currently-locked objects during scavenges, so if during a 63 // promotion failure we encounter either a biased mark word or a 64 // klass which still has a biasable prototype header, we have to 65 // preserve the mark word. This results in oversaving, but promotion 66 // failures are rare, and this avoids adding more complex logic to 67 // the scavengers to call new variants of 68 // BiasedLocking::preserve_marks() / restore_marks() in the middle 69 // of a scavenge when a promotion failure has first been detected. 70 if (has_bias_pattern() || 71 prototype_for_object(obj_containing_mark)->has_bias_pattern()) { 72 return true; 73 } 74 return (!is_unlocked() || !has_no_hash()); 75} 76 77// Should this header be preserved in the case of a promotion failure 78// during scavenge? 79inline bool markOopDesc::must_be_preserved_for_promotion_failure(oop obj_containing_mark) const { 80 if (!UseBiasedLocking) 81 return (!is_unlocked() || !has_no_hash()); 82 return must_be_preserved_with_bias_for_promotion_failure(obj_containing_mark); 83} 84 85 86// Same as must_be_preserved_with_bias_for_promotion_failure() except that 87// it takes a Klass* argument, instead of the object of which this is the mark word. 88inline bool markOopDesc::must_be_preserved_with_bias_for_cms_scavenge(Klass* klass_of_obj_containing_mark) const { 89 assert(UseBiasedLocking, "unexpected"); 90 // CMS scavenges preserve mark words in similar fashion to promotion failures; see above 91 if (has_bias_pattern() || 92 klass_of_obj_containing_mark->prototype_header()->has_bias_pattern()) { 93 return true; 94 } 95 return (!is_unlocked() || !has_no_hash()); 96} 97 98// Same as must_be_preserved_for_promotion_failure() except that 99// it takes a Klass* argument, instead of the object of which this is the mark word. 100inline bool markOopDesc::must_be_preserved_for_cms_scavenge(Klass* klass_of_obj_containing_mark) const { 101 if (!UseBiasedLocking) 102 return (!is_unlocked() || !has_no_hash()); 103 return must_be_preserved_with_bias_for_cms_scavenge(klass_of_obj_containing_mark); 104} 105 106inline markOop markOopDesc::prototype_for_object(oop obj) { 107#ifdef ASSERT 108 markOop prototype_header = obj->klass()->prototype_header(); 109 assert(prototype_header == prototype() || prototype_header->has_bias_pattern(), "corrupt prototype header"); 110#endif 111 return obj->klass()->prototype_header(); 112} 113 114#endif // SHARE_VM_OOPS_MARKOOP_INLINE_HPP 115