duke@435: /*
duke@435:  * Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: // Should this header be preserved during GC?
duke@435: inline bool markOopDesc::must_be_preserved_with_bias(oop obj_containing_mark) const {
duke@435:   assert(UseBiasedLocking, "unexpected");
duke@435:   if (has_bias_pattern()) {
duke@435:     // Will reset bias at end of collection
duke@435:     // Mark words of biased and currently locked objects are preserved separately
duke@435:     return false;
duke@435:   }
duke@435:   markOop prototype_header = prototype_for_object(obj_containing_mark);
duke@435:   if (prototype_header->has_bias_pattern()) {
duke@435:     // Individual instance which has its bias revoked; must return
duke@435:     // true for correctness
duke@435:     return true;
duke@435:   }
duke@435:   return (!is_unlocked() || !has_no_hash());
duke@435: }
duke@435: 
ysr@777: inline bool markOopDesc::must_be_preserved(oop obj_containing_mark) const {
ysr@777:   if (!UseBiasedLocking)
ysr@777:     return (!is_unlocked() || !has_no_hash());
ysr@777:   return must_be_preserved_with_bias(obj_containing_mark);
ysr@777: }
ysr@777: 
duke@435: // Should this header (including its age bits) be preserved in the
duke@435: // case of a promotion failure during scavenge?
duke@435: inline bool markOopDesc::must_be_preserved_with_bias_for_promotion_failure(oop obj_containing_mark) const {
duke@435:   assert(UseBiasedLocking, "unexpected");
duke@435:   // We don't explicitly save off the mark words of biased and
duke@435:   // currently-locked objects during scavenges, so if during a
duke@435:   // promotion failure we encounter either a biased mark word or a
duke@435:   // klass which still has a biasable prototype header, we have to
duke@435:   // preserve the mark word. This results in oversaving, but promotion
duke@435:   // failures are rare, and this avoids adding more complex logic to
duke@435:   // the scavengers to call new variants of
duke@435:   // BiasedLocking::preserve_marks() / restore_marks() in the middle
duke@435:   // of a scavenge when a promotion failure has first been detected.
duke@435:   if (has_bias_pattern() ||
duke@435:       prototype_for_object(obj_containing_mark)->has_bias_pattern()) {
duke@435:     return true;
duke@435:   }
duke@435:   return (this != prototype());
duke@435: }
duke@435: 
ysr@777: inline bool markOopDesc::must_be_preserved_for_promotion_failure(oop obj_containing_mark) const {
ysr@777:   if (!UseBiasedLocking)
ysr@777:     return (this != prototype());
ysr@777:   return must_be_preserved_with_bias_for_promotion_failure(obj_containing_mark);
ysr@777: }
ysr@777: 
ysr@777: 
duke@435: // Should this header (including its age bits) be preserved in the
duke@435: // case of a scavenge in which CMS is the old generation?
duke@435: inline bool markOopDesc::must_be_preserved_with_bias_for_cms_scavenge(klassOop klass_of_obj_containing_mark) const {
duke@435:   assert(UseBiasedLocking, "unexpected");
duke@435:   // CMS scavenges preserve mark words in similar fashion to promotion failures; see above
duke@435:   if (has_bias_pattern() ||
duke@435:       klass_of_obj_containing_mark->klass_part()->prototype_header()->has_bias_pattern()) {
duke@435:     return true;
duke@435:   }
duke@435:   return (this != prototype());
duke@435: }
ysr@777: inline bool markOopDesc::must_be_preserved_for_cms_scavenge(klassOop klass_of_obj_containing_mark) const {
ysr@777:   if (!UseBiasedLocking)
ysr@777:     return (this != prototype());
ysr@777:   return must_be_preserved_with_bias_for_cms_scavenge(klass_of_obj_containing_mark);
ysr@777: }
duke@435: 
duke@435: inline markOop markOopDesc::prototype_for_object(oop obj) {
duke@435: #ifdef ASSERT
duke@435:   markOop prototype_header = obj->klass()->klass_part()->prototype_header();
duke@435:   assert(prototype_header == prototype() || prototype_header->has_bias_pattern(), "corrupt prototype header");
duke@435: #endif
duke@435:   return obj->klass()->klass_part()->prototype_header();
duke@435: }