duke@435: /*
duke@435:  * Copyright 1997-1999 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: # include "incls/_precompiled.incl"
duke@435: # include "incls/_markOop.cpp.incl"
duke@435: 
duke@435: 
duke@435: void markOopDesc::print_on(outputStream* st) const {
duke@435:   if (is_locked()) {
duke@435:     st->print("locked(0x%lx)->", value());
duke@435:     markOop(*(markOop*)value())->print_on(st);
duke@435:   } else {
duke@435:     assert(is_unlocked(), "just checking");
duke@435:     st->print("mark(");
duke@435:     st->print("hash %#lx,", hash());
duke@435:     st->print("age %d)", age());
duke@435:   }
duke@435: }
dcubed@483: 
dcubed@483: 
dcubed@483: // Give advice about whether the oop that contains this markOop
dcubed@483: // should be cached or not.
dcubed@483: bool markOopDesc::should_not_be_cached() const {
dcubed@483:   // the cast is because decode_pointer() isn't marked const
dcubed@483:   if (is_marked() && ((markOopDesc *)this)->decode_pointer() != NULL) {
dcubed@483:     // If the oop containing this markOop is being forwarded, then
dcubed@483:     // we are in the middle of GC and we do not want the containing
dcubed@483:     // oop to be added to a cache. We have no way of knowing whether
dcubed@483:     // the cache has already been visited by the current GC phase so
dcubed@483:     // we don't know whether the forwarded oop will be properly
dcubed@483:     // processed in this phase. If the forwarded oop is not properly
dcubed@483:     // processed, then we'll see strange crashes or asserts during
dcubed@483:     // the next GC run because the markOop will contain an unexpected
dcubed@483:     // value.
dcubed@483:     //
dcubed@483:     // This situation has been seen when we are GC'ing a methodOop
dcubed@483:     // because we use the methodOop while we're GC'ing it. Scary
dcubed@483:     // stuff. Some of the uses the methodOop cause the methodOop to
dcubed@483:     // be added to the OopMapCache in the instanceKlass as a side
dcubed@483:     // effect. This check lets the cache maintainer know when a
dcubed@483:     // cache addition would not be safe.
dcubed@483:     return true;
dcubed@483:   }
dcubed@483: 
dcubed@483:   // caching the containing oop should be just fine
dcubed@483:   return false;
dcubed@483: }