| /* |
| * 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.generational; |
| |
| import org.mmtk.plan.TraceLocal; |
| import org.mmtk.plan.Trace; |
| import org.mmtk.utility.HeaderByte; |
| import org.mmtk.utility.deque.*; |
| import org.mmtk.vm.VM; |
| |
| import org.vmmagic.pragma.*; |
| import org.vmmagic.unboxed.*; |
| |
| /** |
| * This class implments the core functionality for a transitive |
| * closure over the heap graph. |
| */ |
| @Uninterruptible |
| public final class GenNurseryTraceLocal extends TraceLocal { |
| |
| /**************************************************************************** |
| * |
| * Instance fields. |
| */ |
| private final ObjectReferenceDeque modbuf; |
| private final AddressDeque remset; |
| private final AddressPairDeque arrayRemset; |
| |
| |
| /** |
| * Constructor |
| */ |
| public GenNurseryTraceLocal(Trace trace, GenCollector plan) { |
| super(Gen.SCAN_NURSERY, trace); |
| this.modbuf = plan.modbuf; |
| this.remset = plan.remset; |
| this.arrayRemset = plan.arrayRemset; |
| } |
| |
| /**************************************************************************** |
| * |
| * Externally visible Object processing and tracing |
| */ |
| |
| /** |
| * Is the specified object live? |
| * |
| * @param object The object. |
| * @return True if the object is live. |
| */ |
| public boolean isLive(ObjectReference object) { |
| if (object.isNull()) return false; |
| if (Gen.inNursery(object)) { |
| return Gen.nurserySpace.isLive(object); |
| } |
| if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(super.isLive(object)); |
| return true; |
| } |
| |
| /** |
| * 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 (Gen.inNursery(object)) { |
| return Gen.nurserySpace.traceObject(this, object, Gen.ALLOC_MATURE_MINORGC); |
| } |
| return object; |
| } |
| |
| /** |
| * Process any remembered set entries. |
| */ |
| @Inline |
| protected void processRememberedSets() { |
| logMessage(5, "processing modbuf"); |
| ObjectReference obj; |
| while (!(obj = modbuf.pop()).isNull()) { |
| if (VM.DEBUG) VM.debugging.modbufEntry(obj); |
| HeaderByte.markAsUnlogged(obj); |
| scanObject(obj); |
| } |
| logMessage(5, "processing remset"); |
| while (!remset.isEmpty()) { |
| Address loc = remset.pop(); |
| if (VM.DEBUG) VM.debugging.remsetEntry(loc); |
| processRootEdge(loc, false); |
| } |
| logMessage(5, "processing array remset"); |
| arrayRemset.flushLocal(); |
| while (!arrayRemset.isEmpty()) { |
| Address start = arrayRemset.pop1(); |
| Address guard = arrayRemset.pop2(); |
| if (VM.DEBUG) VM.debugging.arrayRemsetEntry(start,guard); |
| while (start.LT(guard)) { |
| processRootEdge(start, false); |
| start = start.plus(BYTES_IN_ADDRESS); |
| } |
| } |
| } |
| |
| /** |
| * Will the object move from now on during the collection. |
| * |
| * @param object The object to query. |
| * @return True if the object is guaranteed not to move. |
| */ |
| public boolean willNotMoveInCurrentCollection(ObjectReference object) { |
| if (object.isNull()) return false; |
| return !Gen.inNursery(object); |
| } |
| |
| } |