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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   */
17  package org.apache.bcel.verifier.structurals;
18  
19  import org.apache.bcel.generic.InstructionHandle;
20  
21  /**
22   * This interface defines properties of JVM bytecode subroutines. Note that it is 'abused' to maintain the top-level
23   * code in a consistent fashion, too.
24   */
25  public interface Subroutine {
26  
27      /**
28       * Returns if the given InstructionHandle refers to an instruction that is part of this subroutine. This is a
29       * convenience method that saves iteration over the InstructionHandle objects returned by getInstructions().
30       *
31       * @param inst The InstructionHandle to test.
32       * @return Whether the given InstructionHandle refers to an instruction that is part of this subroutine.
33       *
34       * @see #getInstructions()
35       */
36      boolean contains(InstructionHandle inst);
37  
38      /**
39       * Returns an int[] containing the indices of the local variable slots accessed by this Subroutine (read-accessed,
40       * write-accessed or both); local variables referenced by subroutines of this subroutine are not included.
41       *
42       * @return An int[] containing the indices of the local variable slots.
43       * @see #getRecursivelyAccessedLocalsIndices()
44       */
45      int[] getAccessedLocalsIndices();
46  
47      /**
48       * Returns all the JsrInstructions that have the first instruction of this subroutine as their target. <B>Must not be
49       * invoked on the 'top-level subroutine'.</B>
50       *
51       * @return The JsrInstructions that have the first instruction of this subroutine as their target.
52       */
53      InstructionHandle[] getEnteringJsrInstructions();
54  
55      /**
56       * Returns all instructions that together form this subroutine. Note that an instruction is part of exactly one
57       * subroutine (the top-level code is considered to be a special subroutine) - else it is not reachable at all (dead
58       * code).
59       *
60       * @return All instructions that together form this subroutine.
61       */
62      InstructionHandle[] getInstructions();
63  
64      /**
65       * Returns the one and only RET that leaves the subroutine. Note that JustIce has a pretty rigid notion of a subroutine.
66       * <B>Must not be invoked on the 'top-level subroutine'.</B>
67       *
68       * @return The one and only RET that leaves the subroutine.
69       *
70       * @see Subroutines
71       */
72      InstructionHandle getLeavingRET();
73  
74      /**
75       * Returns an int[] containing the indices of the local variable slots accessed by this Subroutine (read-accessed,
76       * write-accessed or both); local variables referenced by subroutines of this subroutine are included.
77       *
78       * @return An int[] containing the indices of the local variable slots.
79       * @see #getAccessedLocalsIndices()
80       */
81      int[] getRecursivelyAccessedLocalsIndices();
82  
83      /**
84       * Returns the subroutines that are directly called from this subroutine.
85       *
86       * @return The subroutines that are directly called from this subroutine.
87       */
88      Subroutine[] subSubs();
89  }