001/*
002 *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003 *
004 *  This file is licensed to You under the Eclipse Public License (EPL);
005 *  You may not use this file except in compliance with the License. You
006 *  may obtain a copy of the License at
007 *
008 *      http://www.opensource.org/licenses/eclipse-1.0.php
009 *
010 *  See the COPYRIGHT.txt file distributed with this work for information
011 *  regarding copyright ownership.
012 */
013package org.vmmagic.pragma;
014
015import java.lang.annotation.Retention;
016import java.lang.annotation.Target;
017import java.lang.annotation.RetentionPolicy;
018import java.lang.annotation.ElementType;
019
020/**
021 * Use this annotation to mark fields that are read without the knowledge of the
022 * memory management system. This means that barriers are not triggered and
023 * the reference is also not traced by the garbage collector.<p>
024 *
025 * In order to guarantee that the constraints described above are honored by the compiler,
026 * all accesses to untraced fields must be made when the field is resolved. If the field
027 * were not resolved at the time when the code for the access was being compiled, the
028 * Untraced annotation wouldn't be available (annotations are loaded at resolution
029 * time).
030 */
031@Retention(RetentionPolicy.RUNTIME)
032@Target(ElementType.FIELD)
033public @interface Untraced { }