/*
 * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.graal.hotspotvmconfig;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Refers to a C++ field in the VM.
 */
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface HotSpotVMField {

    /**
     * Types of information this annotation can return.
     */
    enum Type {
        /**
         * Returns the offset of this field within the type. Only valid for instance fields.
         */
        OFFSET,

        /**
         * Returns the absolute address of this field. Only valid for static fields.
         */
        ADDRESS,

        /**
         * Returns the value of this field. Only valid for static fields.
         */
        VALUE;
    }

    /**
     * Specifies what type of information to return.
     *
     * @see Type
     */
    Type get();

    /**
     * Returns the type name containing this field.
     *
     * @return name of containing type
     */
    String type();

    /**
     * Returns the name of this field.
     *
     * @return name of field
     */
    String name();

    /**
     * List of architectures where this constant is required. Names are derived from
     * {@link HotSpotVMConfig#getHostArchitectureName()}. An empty list implies that the constant is
     * required on all architectures.
     */
    @SuppressWarnings("javadoc")
    String[] archs() default {};
}
