001/*
002 *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003 *
004 *  This file is licensed to You under the Eclipse Public License (EPL);
005 *  You may not use this file except in compliance with the License. You
006 *  may obtain a copy of the License at
007 *
008 *      http://www.opensource.org/licenses/eclipse-1.0.php
009 *
010 *  See the COPYRIGHT.txt file distributed with this work for information
011 *  regarding copyright ownership.
012 */
013package org.mmtk.plan.copyms;
014
015import org.mmtk.plan.TraceLocal;
016import org.mmtk.plan.Trace;
017import org.mmtk.policy.Space;
018
019import org.vmmagic.pragma.*;
020import org.vmmagic.unboxed.*;
021
022/**
023 * This class implements the thread-local functionality for a
024 * transitive closure over a coping/mark-sweep hybrid collector.
025 */
026@Uninterruptible
027public final class CopyMSTraceLocal extends TraceLocal {
028
029  /**
030   * @param trace the global trace class to use
031   */
032  public CopyMSTraceLocal(Trace trace) {
033    super(CopyMS.SCAN_COPYMS, trace);
034  }
035
036  /****************************************************************************
037   *
038   * Externally visible Object processing and tracing
039   */
040
041  /**
042   * Is the specified object reachable?
043   */
044  @Override
045  public boolean isLive(ObjectReference object) {
046    if (object.isNull()) return false;
047    if (Space.isInSpace(CopyMS.NURSERY, object)) {
048      return CopyMS.nurserySpace.isLive(object);
049    }
050    if (Space.isInSpace(CopyMS.MARK_SWEEP, object)) {
051      return CopyMS.msSpace.isLive(object);
052    }
053    return super.isLive(object);
054  }
055
056  /**
057   * {@inheritDoc}<p>
058   *
059   * In this instance, we refer objects in the mark-sweep space to the
060   * msSpace for tracing, and defer to the superclass for all others.
061   */
062  @Inline
063  @Override
064  public ObjectReference traceObject(ObjectReference object) {
065    if (object.isNull()) return object;
066    if (Space.isInSpace(CopyMS.NURSERY, object))
067      return CopyMS.nurserySpace.traceObject(this, object, CopyMS.ALLOC_MS);
068    if (Space.isInSpace(CopyMS.MARK_SWEEP, object))
069      return CopyMS.msSpace.traceObject(this, object);
070    return super.traceObject(object);
071  }
072
073  /**
074   * Will this object move from this point on, during the current collection ?
075   *
076   * @param object The object to query.
077   */
078  @Override
079  public boolean willNotMoveInCurrentCollection(ObjectReference object) {
080    return !Space.isInSpace(CopyMS.NURSERY, object);
081  }
082}