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.dexgen.dex.code;
18 
19 import com.android.dexgen.rop.code.RegisterSpecList;
20 import com.android.dexgen.rop.code.SourcePosition;
21 import com.android.dexgen.util.AnnotatedOutput;
22 
23 /**
24  * Pseudo-instruction base class for zero-size (no code emitted)
25  * instructions, which are generally used for tracking metainformation
26  * about the code they are adjacent to.
27  */
28 public abstract class ZeroSizeInsn extends DalvInsn {
29     /**
30      * Constructs an instance. The output address of this instance is initially
31      * unknown ({@code -1}).
32      *
33      * @param position {@code non-null;} source position
34      */
ZeroSizeInsn(SourcePosition position)35     public ZeroSizeInsn(SourcePosition position) {
36         super(Dops.SPECIAL_FORMAT, position, RegisterSpecList.EMPTY);
37     }
38 
39     /** {@inheritDoc} */
40     @Override
codeSize()41     public final int codeSize() {
42         return 0;
43     }
44 
45     /** {@inheritDoc} */
46     @Override
writeTo(AnnotatedOutput out)47     public final void writeTo(AnnotatedOutput out) {
48         // Nothing to do here, for this class.
49     }
50 
51     /** {@inheritDoc} */
52     @Override
withOpcode(Dop opcode)53     public final DalvInsn withOpcode(Dop opcode) {
54         throw new RuntimeException("unsupported");
55     }
56 
57     /** {@inheritDoc} */
58     @Override
withRegisterOffset(int delta)59     public DalvInsn withRegisterOffset(int delta) {
60         return withRegisters(getRegisters().withOffset(delta));
61     }
62 }
63