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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.dexgen.rop.code;
     18 
     19 import com.android.dexgen.rop.type.Type;
     20 import com.android.dexgen.rop.type.TypeList;
     21 
     22 /**
     23  * Instruction which possibly throws. The {@code successors} list in the
     24  * basic block an instance of this class is inside corresponds in-order to
     25  * the list of exceptions handled by this instruction, with the
     26  * no-exception case appended as the final target.
     27  */
     28 public final class ThrowingInsn
     29         extends Insn {
     30     /** {@code non-null;} list of exceptions caught */
     31     private final TypeList catches;
     32 
     33     /**
     34      * Gets the string form of a register spec list to be used as a catches
     35      * list.
     36      *
     37      * @param catches {@code non-null;} the catches list
     38      * @return {@code non-null;} the string form
     39      */
     40     public static String toCatchString(TypeList catches) {
     41         StringBuffer sb = new StringBuffer(100);
     42 
     43         sb.append("catch");
     44 
     45         int sz = catches.size();
     46         for (int i = 0; i < sz; i++) {
     47             sb.append(" ");
     48             sb.append(catches.getType(i).toHuman());
     49         }
     50 
     51         return sb.toString();
     52     }
     53 
     54     /**
     55      * Constructs an instance.
     56      *
     57      * @param opcode {@code non-null;} the opcode
     58      * @param position {@code non-null;} source position
     59      * @param sources {@code non-null;} specs for all the sources
     60      * @param catches {@code non-null;} list of exceptions caught
     61      */
     62     public ThrowingInsn(Rop opcode, SourcePosition position,
     63                         RegisterSpecList sources,
     64                         TypeList catches) {
     65         super(opcode, position, null, sources);
     66 
     67         if (opcode.getBranchingness() != Rop.BRANCH_THROW) {
     68             throw new IllegalArgumentException("bogus branchingness");
     69         }
     70 
     71         if (catches == null) {
     72             throw new NullPointerException("catches == null");
     73         }
     74 
     75         this.catches = catches;
     76     }
     77 
     78     /** {@inheritDoc} */
     79     @Override
     80     public String getInlineString() {
     81         return toCatchString(catches);
     82     }
     83 
     84     /** {@inheritDoc} */
     85     @Override
     86     public TypeList getCatches() {
     87         return catches;
     88     }
     89 
     90     /** {@inheritDoc} */
     91     @Override
     92     public void accept(Visitor visitor) {
     93         visitor.visitThrowingInsn(this);
     94     }
     95 
     96     /** {@inheritDoc} */
     97     @Override
     98     public Insn withAddedCatch(Type type) {
     99         return new ThrowingInsn(getOpcode(), getPosition(),
    100                                 getSources(), catches.withAddedType(type));
    101     }
    102 
    103     /** {@inheritDoc} */
    104     @Override
    105     public Insn withRegisterOffset(int delta) {
    106         return new ThrowingInsn(getOpcode(), getPosition(),
    107                                 getSources().withOffset(delta),
    108                                 catches);
    109     }
    110 
    111     /** {@inheritDoc} */
    112     @Override
    113     public Insn withNewRegisters(RegisterSpec result,
    114             RegisterSpecList sources) {
    115 
    116         return new ThrowingInsn(getOpcode(), getPosition(),
    117                                 sources,
    118                                 catches);
    119     }
    120 }
    121