    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 */
    017package org.apache.bcel.verifier.structurals;
    018
    019import org.apache.bcel.generic.InstructionHandle;
    020
    021/**
    022 * This interface defines properties of JVM bytecode subroutines. Note that it is 'abused' to maintain the top-level
    023 * code in a consistent fashion, too.
    024 */
    025public interface Subroutine {
    026
    027    /**
    028     * Returns if the given InstructionHandle refers to an instruction that is part of this subroutine. This is a
    029     * convenience method that saves iteration over the InstructionHandle objects returned by getInstructions().
    030     *
    031     * @param inst The InstructionHandle to test.
    032     * @return Whether the given InstructionHandle refers to an instruction that is part of this subroutine.
    033     *
    034     * @see #getInstructions()
    035     */
    036    boolean contains(InstructionHandle inst);
    037
    038    /**
    039     * Returns an int[] containing the indices of the local variable slots accessed by this Subroutine (read-accessed,
    040     * write-accessed or both); local variables referenced by subroutines of this subroutine are not included.
    041     *
    042     * @return An int[] containing the indices of the local variable slots.
    043     * @see #getRecursivelyAccessedLocalsIndices()
    044     */
    045    int[] getAccessedLocalsIndices();
    046
    047    /**
    048     * Returns all the JsrInstructions that have the first instruction of this subroutine as their target. <B>Must not be
    049     * invoked on the 'top-level subroutine'.</B>
    050     *
    051     * @return The JsrInstructions that have the first instruction of this subroutine as their target.
    052     */
    053    InstructionHandle[] getEnteringJsrInstructions();
    054
    055    /**
    056     * Returns all instructions that together form this subroutine. Note that an instruction is part of exactly one
    057     * subroutine (the top-level code is considered to be a special subroutine) - else it is not reachable at all (dead
    058     * code).
    059     *
    060     * @return All instructions that together form this subroutine.
    061     */
    062    InstructionHandle[] getInstructions();
    063
    064    /**
    065     * Returns the one and only RET that leaves the subroutine. Note that JustIce has a pretty rigid notion of a subroutine.
    066     * <B>Must not be invoked on the 'top-level subroutine'.</B>
    067     *
    068     * @return The one and only RET that leaves the subroutine.
    069     *
    070     * @see Subroutines
    071     */
    072    InstructionHandle getLeavingRET();
    073
    074    /**
    075     * Returns an int[] containing the indices of the local variable slots accessed by this Subroutine (read-accessed,
    076     * write-accessed or both); local variables referenced by subroutines of this subroutine are included.
    077     *
    078     * @return An int[] containing the indices of the local variable slots.
    079     * @see #getAccessedLocalsIndices()
    080     */
    081    int[] getRecursivelyAccessedLocalsIndices();
    082
    083    /**
    084     * Returns the subroutines that are directly called from this subroutine.
    085     *
    086     * @return The subroutines that are directly called from this subroutine.
    087     */
    088    Subroutine[] subSubs();
    089}