/*
* This file is part of the Jikes RVM project (http://jikesrvm.org).
*
* This file is licensed to You under the Common Public License (CPL);
* 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/cpl1.0.php
*
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership.
*/
package org.mmtk.plan.generational;
import org.mmtk.plan.TraceLocal;
import org.mmtk.plan.Trace;
import org.mmtk.utility.deque.*;
import org.mmtk.vm.VM;
import org.vmmagic.unboxed.*;
import org.vmmagic.pragma.*;
/**
* This abstract class implments the core functionality for a transitive
* closure over the heap graph.
*/
@Uninterruptible public abstract class GenMatureTraceLocal extends TraceLocal {
/****************************************************************************
*
* Instance fields.
*/
private final AddressDeque remset;
private final AddressPairDeque arrayRemset;
/****************************************************************************
*
* Initialization
*/
/**
* Constructor
*/
public GenMatureTraceLocal(Trace trace, GenCollector plan) {
super(Gen.SCAN_MATURE, trace);
this.remset = plan.remset;
this.arrayRemset = plan.arrayRemset;
}
/****************************************************************************
*
* Object processing and tracing
*/
/**
* Is the specified object live?
*
* @param object The object.
* @return True if the object is live.
*/
@Inline
public boolean isLive(ObjectReference object) {
if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!object.isNull());
if (object.toAddress().GE(Gen.NURSERY_START)) {
if (object.toAddress().LT(Gen.NURSERY_END))
return Gen.nurserySpace.isLive(object);
else
return Gen.ploSpace.isLive(object);
}
return super.isLive(object);
}
/**
* Return true if this object is guaranteed not to move during this
* collection (i.e. this object is defintely not an unforwarded
* object).
*
* @param object
* @return True if this object is guaranteed not to move during this
* collection.
*/
public boolean willNotMoveInCurrentCollection(ObjectReference object) {
if (object.toAddress().GE(Gen.NURSERY_START))
return object.toAddress().GE(Gen.NURSERY_END);
return super.willNotMoveInCurrentCollection(object);
}
/**
* This method is the core method during the trace of the object graph.
* The role of this method is to:
*
* 1. Ensure the traced object is not collected.
* 2. If this is the first visit to the object enqueue it to be scanned.
* 3. Return the forwarded reference to the object.
*
* @param object The object to be traced.
* @return The new reference to the same object instance.
*/
@Inline
public ObjectReference traceObject(ObjectReference object) {
if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!object.isNull());
if (object.toAddress().GE(Gen.NURSERY_START)) {
if (object.toAddress().LT(Gen.NURSERY_END))
return Gen.nurserySpace.traceObject(this, object, Gen.ALLOC_MATURE_MAJORGC);
else
return Gen.ploSpace.traceObject(this, object);
}
return super.traceObject(object);
}
/**
* Process any remembered set entries.
*/
protected void processRememberedSets() {
logMessage(5, "clearing remset");
while (!remset.isEmpty()) {
remset.pop();
}
logMessage(5, "clearing array remset");
while (!arrayRemset.isEmpty()) {
arrayRemset.pop1();
arrayRemset.pop2();
}
}
}