    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 *  Unless required by applicable law or agreed to in writing, software
    012 *  distributed under the License is distributed on an "AS IS" BASIS,
    013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 *  See the License for the specific language governing permissions and
    015 *  limitations under the License.
    016 *
    017 */
    018package org.apache.bcel.verifier.structurals;
    019
    020import org.apache.bcel.generic.InstructionHandle;
    021
    022/**
    023 * This interface defines properties of JVM bytecode subroutines. Note that it is 'abused' to maintain the top-level
    024 * code in a consistent fashion, too.
    025 */
    026public interface Subroutine {
    027
    028    /**
    029     * Returns if the given InstructionHandle refers to an instruction that is part of this subroutine. This is a
    030     * convenience method that saves iteration over the InstructionHandle objects returned by getInstructions().
    031     *
    032     * @param inst The InstructionHandle to test.
    033     * @return Whether the given InstructionHandle refers to an instruction that is part of this subroutine.
    034     *
    035     * @see #getInstructions()
    036     */
    037    boolean contains(InstructionHandle inst);
    038
    039    /**
    040     * Returns an int[] containing the indices of the local variable slots accessed by this Subroutine (read-accessed,
    041     * write-accessed or both); local variables referenced by subroutines of this subroutine are not included.
    042     *
    043     * @return An int[] containing the indices of the local variable slots.
    044     * @see #getRecursivelyAccessedLocalsIndices()
    045     */
    046    int[] getAccessedLocalsIndices();
    047
    048    /**
    049     * Returns all the JsrInstructions that have the first instruction of this subroutine as their target. <B>Must not be
    050     * invoked on the 'top-level subroutine'.</B>
    051     *
    052     * @return The JsrInstructions that have the first instruction of this subroutine as their target.
    053     */
    054    InstructionHandle[] getEnteringJsrInstructions();
    055
    056    /**
    057     * Returns all instructions that together form this subroutine. Note that an instruction is part of exactly one
    058     * subroutine (the top-level code is considered to be a special subroutine) - else it is not reachable at all (dead
    059     * code).
    060     *
    061     * @return All instructions that together form this subroutine.
    062     */
    063    InstructionHandle[] getInstructions();
    064
    065    /**
    066     * Returns the one and only RET that leaves the subroutine. Note that JustIce has a pretty rigid notion of a subroutine.
    067     * <B>Must not be invoked on the 'top-level subroutine'.</B>
    068     *
    069     * @return The one and only RET that leaves the subroutine.
    070     *
    071     * @see Subroutines
    072     */
    073    InstructionHandle getLeavingRET();
    074
    075    /**
    076     * Returns an int[] containing the indices of the local variable slots accessed by this Subroutine (read-accessed,
    077     * write-accessed or both); local variables referenced by subroutines of this subroutine are included.
    078     *
    079     * @return An int[] containing the indices of the local variable slots.
    080     * @see #getAccessedLocalsIndices()
    081     */
    082    int[] getRecursivelyAccessedLocalsIndices();
    083
    084    /**
    085     * Returns the subroutines that are directly called from this subroutine.
    086     *
    087     * @return The subroutines that are directly called from this subroutine.
    088     */
    089    Subroutine[] subSubs();
    090}