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
17package com.android.dx.dex.code;
18
19import com.android.dx.rop.code.BasicBlock;
20import com.android.dx.rop.code.BasicBlockList;
21import com.android.dx.rop.code.Insn;
22import com.android.dx.rop.code.RopMethod;
23import com.android.dx.rop.code.SourcePosition;
24
25/**
26 * Container for the set of {@link CodeAddress} instances associated with
27 * the blocks of a particular method. Each block has a corresponding
28 * start address, end address, and last instruction address.
29 */
30public final class BlockAddresses {
31    /** {@code non-null;} array containing addresses for the start of each basic
32     * block (indexed by basic block label) */
33    private final CodeAddress[] starts;
34
35    /** {@code non-null;} array containing addresses for the final instruction
36     * of each basic block (indexed by basic block label) */
37    private final CodeAddress[] lasts;
38
39    /** {@code non-null;} array containing addresses for the end (just past the
40     * final instruction) of each basic block (indexed by basic block
41     * label) */
42    private final CodeAddress[] ends;
43
44    /**
45     * Constructs an instance.
46     *
47     * @param method {@code non-null;} the method to have block addresses for
48     */
49    public BlockAddresses(RopMethod method) {
50        BasicBlockList blocks = method.getBlocks();
51        int maxLabel = blocks.getMaxLabel();
52
53        this.starts = new CodeAddress[maxLabel];
54        this.lasts = new CodeAddress[maxLabel];
55        this.ends = new CodeAddress[maxLabel];
56
57        setupArrays(method);
58    }
59
60    /**
61     * Gets the instance for the start of the given block.
62     *
63     * @param block {@code non-null;} the block in question
64     * @return {@code non-null;} the appropriate instance
65     */
66    public CodeAddress getStart(BasicBlock block) {
67        return starts[block.getLabel()];
68    }
69
70    /**
71     * Gets the instance for the start of the block with the given label.
72     *
73     * @param label {@code non-null;} the label of the block in question
74     * @return {@code non-null;} the appropriate instance
75     */
76    public CodeAddress getStart(int label) {
77        return starts[label];
78    }
79
80    /**
81     * Gets the instance for the final instruction of the given block.
82     *
83     * @param block {@code non-null;} the block in question
84     * @return {@code non-null;} the appropriate instance
85     */
86    public CodeAddress getLast(BasicBlock block) {
87        return lasts[block.getLabel()];
88    }
89
90    /**
91     * Gets the instance for the final instruction of the block with
92     * the given label.
93     *
94     * @param label {@code non-null;} the label of the block in question
95     * @return {@code non-null;} the appropriate instance
96     */
97    public CodeAddress getLast(int label) {
98        return lasts[label];
99    }
100
101    /**
102     * Gets the instance for the end (address after the final instruction)
103     * of the given block.
104     *
105     * @param block {@code non-null;} the block in question
106     * @return {@code non-null;} the appropriate instance
107     */
108    public CodeAddress getEnd(BasicBlock block) {
109        return ends[block.getLabel()];
110    }
111
112    /**
113     * Gets the instance for the end (address after the final instruction)
114     * of the block with the given label.
115     *
116     * @param label {@code non-null;} the label of the block in question
117     * @return {@code non-null;} the appropriate instance
118     */
119    public CodeAddress getEnd(int label) {
120        return ends[label];
121    }
122
123    /**
124     * Sets up the address arrays.
125     */
126    private void setupArrays(RopMethod method) {
127        BasicBlockList blocks = method.getBlocks();
128        int sz = blocks.size();
129
130        for (int i = 0; i < sz; i++) {
131            BasicBlock one = blocks.get(i);
132            int label = one.getLabel();
133            Insn insn = one.getInsns().get(0);
134
135            starts[label] = new CodeAddress(insn.getPosition());
136
137            SourcePosition pos = one.getLastInsn().getPosition();
138
139            lasts[label] = new CodeAddress(pos);
140            ends[label] = new CodeAddress(pos);
141        }
142    }
143}
144