| /* |
| * This file is part of the Jikes RVM project (http://jikesrvm.org). |
| * |
| * This file is licensed to You under the Eclipse Public License (EPL); |
| * You may not use this file except in compliance with the License. You |
| * may obtain a copy of the License at |
| * |
| * http://www.opensource.org/licenses/eclipse-1.0.php |
| * |
| * See the COPYRIGHT.txt file distributed with this work for information |
| * regarding copyright ownership. |
| */ |
| package org.mmtk.plan.refcount.backuptrace; |
| |
| import org.mmtk.plan.TransitiveClosure; |
| import org.mmtk.plan.refcount.RCBase; |
| import org.mmtk.plan.refcount.RCHeader; |
| import org.mmtk.policy.Space; |
| import org.mmtk.vm.VM; |
| |
| import org.vmmagic.pragma.*; |
| import org.vmmagic.unboxed.*; |
| |
| /** |
| * This class is the fundamental mechanism for performing a |
| * transitive closure over an object graph.<p> |
| * |
| * @see org.mmtk.plan.TraceLocal |
| */ |
| @Uninterruptible |
| public final class BTDecMarked extends TransitiveClosure { |
| |
| /** |
| * Trace an edge during GC. |
| * |
| * @param source The source of the reference. |
| * @param slot The location containing the object reference. |
| */ |
| @Inline |
| public void processEdge(ObjectReference source, Address slot) { |
| ObjectReference object = slot.loadObjectReference(); |
| if (!object.isNull()) { |
| if ((Space.isInSpace(RCBase.REF_COUNT, object) && RCBase.rcSpace.isLive(object)) || |
| Space.isInSpace(RCBase.REF_COUNT_LOS, object) || |
| Space.isInSpace(RCBase.IMMORTAL, object)) { |
| int result = RCHeader.decRC(object); |
| if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(result != RCHeader.DEC_KILL || !RCHeader.isMarked(object)); |
| } |
| } |
| } |
| } |