    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 *   https://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.bcel.verifier.structurals;
    020
    021import org.apache.bcel.generic.InstructionHandle;
    022
    023/**
    024 * This interface defines properties of JVM bytecode subroutines. Note that it is 'abused' to maintain the top-level
    025 * code in a consistent fashion, too.
    026 */
    027public interface Subroutine {
    028
    029    /**
    030     * Returns if the given InstructionHandle refers to an instruction that is part of this subroutine. This is a
    031     * convenience method that saves iteration over the InstructionHandle objects returned by getInstructions().
    032     *
    033     * @param inst The InstructionHandle to test.
    034     * @return Whether the given InstructionHandle refers to an instruction that is part of this subroutine.
    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     * <strong>Must not be invoked on the 'top-level subroutine'.</strong>
    068     *
    069     * @return The one and only RET that leaves the subroutine.
    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}