/*
* 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.refcount.generational;
import org.mmtk.plan.TraceLocal;
import org.mmtk.plan.TransitiveClosure;
import org.mmtk.plan.refcount.RCBaseCollector;
import org.mmtk.plan.refcount.RCHeader;
import org.mmtk.policy.CopySpace;
import org.mmtk.policy.ExplicitFreeListLocal;
import org.mmtk.policy.ExplicitFreeListSpace;
import org.mmtk.utility.Constants;
import org.mmtk.vm.VM;
import org.vmmagic.pragma.*;
import org.vmmagic.unboxed.*;
/**
* This class implements <i>per-collector thread</i> behavior
* and state for the <i>GenRC</i> plan, which implements a generational
* reference counting collector.<p>
*
* Specifically, this class defines <i>RC</i> collection behavior
* (through <code>trace</code> and the <code>collectionPhase</code>
* method).<p>
*
* @see GenRC for an overview of the reference counting algorithm.<p>
*
* FIXME The SegregatedFreeList class (and its decendents such as
* MarkSweepLocal) does not properly separate mutator and collector
* behaviors, so the ms field below should really not exist in
* this class as there is no collection-time allocation in this
* collector.
*
* @see GenRC
* @see GenRCMutator
* @see org.mmtk.plan.StopTheWorldCollector
* @see org.mmtk.plan.CollectorContext
*/
@Uninterruptible public abstract class GenRCCollector extends RCBaseCollector
implements Constants {
/****************************************************************************
* Instance fields
*/
public final ExplicitFreeListLocal rc;
public final GenRCTraceLocal trace;
public final GenRCModifiedProcessor modProcessor;
/****************************************************************************
* Initialization
*/
/**
* Constructor
*/
public GenRCCollector() {
trace = new GenRCTraceLocal(global().rcTrace);
rc = new ExplicitFreeListLocal(GenRC.rcSpace);
modProcessor = new GenRCModifiedProcessor(trace);
}
/****************************************************************************
*
* Collection
*/
/**
* Perform a per-collector collection phase.
*
* @param phaseId The collection phase to perform
* @param primary Perform any single-threaded activities using this thread.
*/
@Inline
public void collectionPhase(short phaseId, boolean primary) {
if (phaseId == GenRC.PREPARE) {
super.collectionPhase(phaseId, primary);
rc.prepare();
return;
}
if (phaseId == GenRC.RELEASE) {
super.collectionPhase(phaseId, primary);
rc.release();
return;
}
super.collectionPhase(phaseId, primary);
}
/****************************************************************************
*
* Collection-time allocation
*/
/**
* Allocate space for copying an object (this method <i>does not</i>
* copy the object, it only allocates space)
*
* @param original A reference to the original object
* @param bytes The size of the space to be allocated (in bytes)
* @param align The requested alignment
* @param offset The alignment offset
* @return The address of the first byte of the allocated region
*/
@Inline
public final Address allocCopy(ObjectReference original, int bytes,
int align, int offset, int allocator) {
if (VM.VERIFY_ASSERTIONS) {
VM.assertions._assert(allocator == GenRC.ALLOC_RC);
}
return rc.alloc(bytes, align, offset);
}
/**
* Perform any post-copy actions. In this case nothing is required.
*
* @param object The newly allocated object
* @param typeRef the type reference for the instance being created
* @param bytes The size of the space to be allocated (in bytes)
*/
@Inline
public final void postCopy(ObjectReference object, ObjectReference typeRef,
int bytes, int allocator) {
CopySpace.clearGCBits(object);
RCHeader.initializeHeader(object, typeRef, false);
RCHeader.makeUnlogged(object);
ExplicitFreeListSpace.unsyncSetLiveBit(object);
}
/****************************************************************************
*
* Miscellaneous
*/
/** @return The active global plan as an <code>MS</code> instance. */
@Inline
private static GenRC global() {
return (GenRC) VM.activePlan.global();
}
/** @return The current trace instance. */
public final TraceLocal getCurrentTrace() {
return trace;
}
/** @return The current modified object processor. */
public final TransitiveClosure getModifiedProcessor() {
return modProcessor;
}
}