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     */
013    package org.vmmagic;
014    
015    import java.lang.annotation.Retention;
016    import java.lang.annotation.RetentionPolicy;
017    import java.lang.annotation.Target;
018    import java.lang.annotation.ElementType;
019    import java.lang.annotation.Inherited;
020    
021    /**
022     * An intrinsic method is a method that is built in (that is, intrinsic) to the compiler
023     * rather than part of a class library. Intrinsic methods are an escape hatch to provide
024     * "magic" that is inexpressible int the Java programming language. A compiler intrinsic
025     * will usually generate a specific code sequence that is inlined and optimized as part
026     * by the compiler. Unless an intrinsic method is expected to be executed in a non-intrinsic
027     * aware compiler, the body of the method should be empty.
028     *
029     * <p>If the Intrinsic annotation is applied to a method then then the method is a compiler
030     * intrinsic. If the Intrinsic annotation is applied to a class then all the methods of
031     * the class AND all subclasses are intrinsic.</p>
032     *
033     * <p>NOTE: At the current time the Intrinsic annotation is only used for documentation
034     * purposes but in the near future it is expected that the semantics of the annotation will
035     * be enforced by the compiler.</p>
036     */
037    @Retention(RetentionPolicy.RUNTIME)
038    @Target({ElementType.TYPE,ElementType.METHOD})
039    @Inherited
040    public @interface Intrinsic { }