/*
* 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.nogc;
import org.mmtk.plan.TraceLocal;
import org.mmtk.plan.Trace;
import org.mmtk.policy.Space;
import org.vmmagic.pragma.*;
import org.vmmagic.unboxed.*;
/**
* This class implements the thread-local core functionality for a transitive
* closure over the heap graph.
*/
@Uninterruptible
public final class NoGCTraceLocal extends TraceLocal {
/**
* Constructor
*/
public NoGCTraceLocal(Trace trace) {
super(trace);
}
/****************************************************************************
* Externally visible Object processing and tracing
*/
/**
* Is the specified object live?
*
* @param object The object.
* @return <code>true</code> if the object is live.
*/
@Override
public boolean isLive(ObjectReference object) {
if (object.isNull()) return false;
if (Space.isInSpace(NoGC.NOGC, object)) {
return NoGC.noGCSpace.isLive(object);
}
return super.isLive(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
@Override
public ObjectReference traceObject(ObjectReference object) {
if (object.isNull()) return object;
if (Space.isInSpace(NoGC.NOGC, object))
return NoGC.noGCSpace.traceObject(this, object);
return super.traceObject(object);
}
}