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.generational.copying;
014
015import org.mmtk.plan.generational.Gen;
016import org.mmtk.plan.generational.GenCollector;
017import org.mmtk.plan.Plan;
018import org.mmtk.plan.TraceLocal;
019import org.mmtk.policy.CopyLocal;
020import org.mmtk.utility.ForwardingWord;
021import org.mmtk.utility.HeaderByte;
022import org.mmtk.utility.alloc.Allocator;
023import org.mmtk.vm.VM;
024
025import org.vmmagic.unboxed.*;
026import org.vmmagic.pragma.*;
027
028/**
029 * This class implements <i>per-collector thread</i> behavior and state for
030 * the <code>GenCopy</code> two-generational copying collector.<p>
031 *
032 * Specifically, this class defines semantics specific to the collection of
033 * the mature generation (<code>GenCollector</code> defines nursery semantics).
034 * In particular the mature space allocator is defined (for collection-time
035 * allocation into the mature space), and the mature space per-collector thread
036 * collection time semantics are defined.<p>
037 *
038 * @see GenCopy for a description of the <code>GenCopy</code> algorithm.
039 *
040 * @see GenCopy
041 * @see GenCopyMutator
042 * @see GenCollector
043 * @see org.mmtk.plan.StopTheWorldCollector
044 * @see org.mmtk.plan.CollectorContext
045 */
046@Uninterruptible
047public class GenCopyCollector extends GenCollector {
048
049  /******************************************************************
050   * Instance fields
051   */
052
053  /** The allocator for the mature space */
054  private final CopyLocal mature;
055
056  /** The trace object for full-heap collections */
057  private final GenCopyMatureTraceLocal matureTrace;
058
059  /****************************************************************************
060   *
061   * Initialization
062   */
063
064  /**
065   * Constructor
066   */
067  public GenCopyCollector() {
068    mature = new CopyLocal(GenCopy.toSpace());
069    matureTrace = new GenCopyMatureTraceLocal(global().matureTrace, this);
070  }
071
072  /****************************************************************************
073   *
074   * Collection-time allocation
075   */
076
077  /**
078   * {@inheritDoc}
079   */
080  @Override
081  @Inline
082  public Address allocCopy(ObjectReference original, int bytes,
083      int align, int offset, int allocator) {
084    if (allocator == Plan.ALLOC_LOS) {
085      if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(Allocator.getMaximumAlignedSize(bytes, align) > Plan.MAX_NON_LOS_COPY_BYTES);
086      return los.alloc(bytes, align, offset);
087    } else {
088      if (VM.VERIFY_ASSERTIONS) {
089        VM.assertions._assert(bytes <= Plan.MAX_NON_LOS_COPY_BYTES);
090        VM.assertions._assert(allocator == GenCopy.ALLOC_MATURE_MINORGC ||
091            allocator == GenCopy.ALLOC_MATURE_MAJORGC);
092      }
093      return mature.alloc(bytes, align, offset);
094    }
095  }
096
097  /**
098   * {@inheritDoc}<p>
099   *
100   * In this case we clear any bits used for this object's GC metadata.
101   */
102  @Override
103  @Inline
104  public final void postCopy(ObjectReference object, ObjectReference typeRef,
105      int bytes, int allocator) {
106    ForwardingWord.clearForwardingBits(object);
107    if (allocator == Plan.ALLOC_LOS)
108      Plan.loSpace.initializeHeader(object, false);
109    else if (GenCopy.IGNORE_REMSETS)
110      GenCopy.immortalSpace.traceObject(getCurrentTrace(), object); // FIXME this does not look right
111    if (Gen.USE_OBJECT_BARRIER)
112      HeaderByte.markAsUnlogged(object);
113  }
114
115
116  /*****************************************************************************
117   *
118   * Collection
119   */
120
121  /**
122   * {@inheritDoc}
123   */
124  @Override
125  public void collectionPhase(short phaseId, boolean primary) {
126    if (global().traceFullHeap()) {
127      if (phaseId == GenCopy.PREPARE) {
128        super.collectionPhase(phaseId, primary);
129        if (global().gcFullHeap) mature.rebind(GenCopy.toSpace());
130      }
131      if (phaseId == GenCopy.CLOSURE) {
132        matureTrace.completeTrace();
133        return;
134      }
135      if (phaseId == GenCopy.RELEASE) {
136        matureTrace.release();
137        super.collectionPhase(phaseId, primary);
138        return;
139      }
140    }
141    super.collectionPhase(phaseId, primary);
142  }
143
144  /*****************************************************************************
145   *
146   * Miscellaneous
147   */
148
149  /** @return The active global plan as a <code>GenCopy</code> instance. */
150  private static GenCopy global() {
151    return (GenCopy) VM.activePlan.global();
152  }
153
154  /** Show the status of the mature allocator. */
155  protected final void showMature() {
156    mature.show();
157  }
158
159  @Override
160  public final TraceLocal getFullHeapTrace() {
161    return matureTrace;
162  }
163}