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     */
013    package org.mmtk.plan.generational.immix;
014    
015    import static org.mmtk.policy.immix.ImmixConstants.MARK_LINE_AT_SCAN_TIME;
016    
017    import org.mmtk.plan.generational.GenCollector;
018    import org.mmtk.plan.generational.GenMatureTraceLocal;
019    import org.mmtk.plan.Trace;
020    import org.mmtk.policy.Space;
021    import org.mmtk.utility.Log;
022    import org.mmtk.utility.options.Options;
023    import org.mmtk.vm.VM;
024    
025    import org.vmmagic.unboxed.*;
026    import org.vmmagic.pragma.*;
027    
028    /**
029     * This class implements the core functionality for a transitive
030     * closure over the heap graph, specifically in a defragmenting pass over
031     * a generational immix collector.
032     */
033    @Uninterruptible
034    public final class GenImmixMatureDefragTraceLocal extends GenMatureTraceLocal{
035    
036      /**
037       * Constructor
038       */
039      public GenImmixMatureDefragTraceLocal(Trace global, GenCollector plan) {
040        super(-1, global, plan);
041      }
042    
043      @Override
044      public boolean isLive(ObjectReference object) {
045        if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(GenImmix.immixSpace.inImmixDefragCollection());
046        if (object.isNull()) return false;
047        if (Space.isInSpace(GenImmix.IMMIX, object)) {
048          return GenImmix.immixSpace.isLive(object);
049        }
050        return super.isLive(object);
051      }
052    
053      @Override
054      @Inline
055      public ObjectReference traceObject(ObjectReference object) {
056        if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(GenImmix.immixSpace.inImmixDefragCollection());
057        if (object.isNull()) return object;
058        if (Space.isInSpace(GenImmix.IMMIX, object))
059          return GenImmix.immixSpace.traceObject(this, object, GenImmix.ALLOC_MATURE_MAJORGC);
060        return super.traceObject(object);
061      }
062    
063      @Override
064      public boolean willNotMoveInCurrentCollection(ObjectReference object) {
065        if (Space.isInSpace(GenImmix.IMMIX, object)) {
066          return GenImmix.immixSpace.willNotMoveThisGC(object);
067        }
068        return super.willNotMoveInCurrentCollection(object);
069      }
070    
071      @Inline
072      @Override
073      protected void scanObject(ObjectReference object) {
074        if (VM.VERIFY_ASSERTIONS && Options.verbose.getValue() >= 9) {
075          Log.write("SO["); Log.write(object); Log.writeln("]");
076        }
077        super.scanObject(object);
078        if (MARK_LINE_AT_SCAN_TIME && Space.isInSpace(GenImmix.IMMIX, object))
079          GenImmix.immixSpace.markLines(object);
080      }
081    }