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      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.BasicBlock;
     20 import com.android.dx.rop.code.BasicBlockList;
     21 import com.android.dx.rop.code.Insn;
     22 import com.android.dx.rop.code.RopMethod;
     23 import 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  */
     30 public 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