| /* |
| * 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.poisoned; |
| |
| import org.mmtk.plan.marksweep.MSMutator; |
| import org.mmtk.vm.VM; |
| |
| import org.vmmagic.pragma.*; |
| import org.vmmagic.unboxed.Address; |
| import org.vmmagic.unboxed.ObjectReference; |
| import org.vmmagic.unboxed.Word; |
| |
| /** |
| * This class implements a poisoned collector, that is essentially a test |
| * case for read and write barriers in the VM. |
| */ |
| @Uninterruptible |
| public class PoisonedMutator extends MSMutator { |
| |
| /**************************************************************************** |
| * |
| * Write and read barriers. By default do nothing, override if |
| * appropriate. |
| */ |
| |
| /** |
| * A new reference is about to be created. Take appropriate write |
| * barrier actions.<p> |
| * |
| * <b>By default do nothing, override if appropriate.</b> |
| * |
| * @param src The object into which the new reference will be stored |
| * @param slot The address into which the new reference will be |
| * stored. |
| * @param tgt The target of the new reference |
| * @param metaDataA A value that assists the host VM in creating a store |
| * @param metaDataB A value that assists the host VM in creating a store |
| * @param mode The context in which the store occurred |
| */ |
| @Inline |
| @Override |
| public void objectReferenceWrite(ObjectReference src, Address slot, ObjectReference tgt, Word metaDataA, Word metaDataB, int mode) { |
| VM.barriers.wordWrite(src, Poisoned.poison(tgt), metaDataA, metaDataB, mode); |
| } |
| |
| /** |
| * Attempt to atomically exchange the value in the given slot |
| * with the passed replacement value. If a new reference is |
| * created, we must then take appropriate write barrier actions.<p> |
| * |
| * <b>By default do nothing, override if appropriate.</b> |
| * |
| * @param src The object into which the new reference will be stored |
| * @param slot The address into which the new reference will be |
| * stored. |
| * @param old The old reference to be swapped out |
| * @param tgt The target of the new reference |
| * @param metaDataA A value that assists the host VM in creating a store |
| * @param metaDataB A value that assists the host VM in creating a store |
| * @param mode The context in which the store occurred |
| * @return True if the swap was successful. |
| */ |
| @Override |
| public boolean objectReferenceTryCompareAndSwap(ObjectReference src, Address slot, ObjectReference old, ObjectReference tgt, |
| Word metaDataA, Word metaDataB, int mode) { |
| return VM.barriers.wordTryCompareAndSwap(src, Poisoned.poison(old), Poisoned.poison(tgt), metaDataA, metaDataB, mode); |
| } |
| |
| /** |
| * Read a reference. Take appropriate read barrier action, and |
| * return the value that was read.<p> This is a <b>substituting<b> |
| * barrier. The call to this barrier takes the place of a load.<p> |
| * |
| * @param src The object reference holding the field being read. |
| * @param slot The address of the slot being read. |
| * @param metaDataA A value that assists the host VM in creating a load |
| * @param metaDataB A value that assists the host VM in creating a load |
| * @param mode The context in which the load occurred |
| * @return The reference that was read. |
| */ |
| @Inline |
| @Override |
| public ObjectReference objectReferenceRead(ObjectReference src, Address slot, Word metaDataA, Word metaDataB, int mode) { |
| return Poisoned.depoison(VM.barriers.wordRead(src, metaDataA, metaDataB, mode)); |
| } |
| } |