1 /*
2  * Copyright (C) 2007 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.dx.dex.code;
18 
19 import com.android.dx.rop.code.RegisterSpecList;
20 import com.android.dx.rop.code.SourcePosition;
21 
22 /**
23  * Pseudo-instruction which is used to track an address within a code
24  * array. Instances are used for such things as branch targets and
25  * exception handler ranges. Its code size is zero, and so instances
26  * do not in general directly wind up in any output (either
27  * human-oriented or binary file).
28  */
29 public final class CodeAddress extends ZeroSizeInsn {
30     /** If this address should bind closely to the following real instruction */
31     private final boolean bindsClosely;
32 
33     /**
34      * Constructs an instance. The output address of this instance is initially
35      * unknown ({@code -1}).
36      *
37      * @param position {@code non-null;} source position
38      */
CodeAddress(SourcePosition position)39     public CodeAddress(SourcePosition position) {
40         this(position, false);
41     }
42 
43     /**
44      * Constructs an instance. The output address of this instance is initially
45      * unknown ({@code -1}).
46      *
47      * @param position {@code non-null;} source position
48      * @param bindsClosely if the address should bind closely to the following
49      *                     real instruction.
50      */
CodeAddress(SourcePosition position, boolean bindsClosely)51     public CodeAddress(SourcePosition position, boolean bindsClosely) {
52         super(position);
53         this.bindsClosely = bindsClosely;
54     }
55 
56     /** {@inheritDoc} */
57     @Override
withRegisters(RegisterSpecList registers)58     public final DalvInsn withRegisters(RegisterSpecList registers) {
59         return new CodeAddress(getPosition());
60     }
61 
62     /** {@inheritDoc} */
63     @Override
argString()64     protected String argString() {
65         return null;
66     }
67 
68     /** {@inheritDoc} */
69     @Override
listingString0(boolean noteIndices)70     protected String listingString0(boolean noteIndices) {
71         return "code-address";
72     }
73 
74     /**
75      * Gets whether this address binds closely to the following "real"
76      * (non-zero-length) instruction.
77      *
78      * When a prefix is added to an instruction (for example, to move a value
79      * from a high register to a low register), this determines whether this
80      * {@code CodeAddress} will point to the prefix, or to the instruction
81      * itself.
82      *
83      * If bindsClosely is true, the address will point to the instruction
84      * itself, otherwise it will point to the prefix (if any)
85      *
86      * @return true if this address binds closely to the next real instruction
87      */
getBindsClosely()88     public boolean getBindsClosely() {
89         return bindsClosely;
90     }
91 }
92