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.cf.code; 18 19import com.android.dx.rop.type.Type; 20import com.android.dx.rop.type.TypeBearer; 21import com.android.dx.util.Hex; 22 23/** 24 * Representation of a subroutine return address. In Java verification, 25 * somewhat counterintuitively, the salient bit of information you need to 26 * know about a return address is the <i>start address</i> of the subroutine 27 * being returned from, not the address being returned <i>to</i>, so that's 28 * what instances of this class hang onto. 29 */ 30public final class ReturnAddress implements TypeBearer { 31 /** {@code >= 0;} the start address of the subroutine being returned from */ 32 private final int subroutineAddress; 33 34 /** 35 * Constructs an instance. 36 * 37 * @param subroutineAddress {@code >= 0;} the start address of the 38 * subroutine being returned from 39 */ 40 public ReturnAddress(int subroutineAddress) { 41 if (subroutineAddress < 0) { 42 throw new IllegalArgumentException("subroutineAddress < 0"); 43 } 44 45 this.subroutineAddress = subroutineAddress; 46 } 47 48 /** {@inheritDoc} */ 49 @Override 50 public String toString() { 51 return ("<addr:" + Hex.u2(subroutineAddress) + ">"); 52 } 53 54 /** {@inheritDoc} */ 55 public String toHuman() { 56 return toString(); 57 } 58 59 /** {@inheritDoc} */ 60 public Type getType() { 61 return Type.RETURN_ADDRESS; 62 } 63 64 /** {@inheritDoc} */ 65 public TypeBearer getFrameType() { 66 return this; 67 } 68 69 /** {@inheritDoc} */ 70 public int getBasicType() { 71 return Type.RETURN_ADDRESS.getBasicType(); 72 } 73 74 /** {@inheritDoc} */ 75 public int getBasicFrameType() { 76 return Type.RETURN_ADDRESS.getBasicFrameType(); 77 } 78 79 /** {@inheritDoc} */ 80 public boolean isConstant() { 81 return false; 82 } 83 84 /** {@inheritDoc} */ 85 @Override 86 public boolean equals(Object other) { 87 if (!(other instanceof ReturnAddress)) { 88 return false; 89 } 90 91 return subroutineAddress == ((ReturnAddress) other).subroutineAddress; 92 } 93 94 /** {@inheritDoc} */ 95 @Override 96 public int hashCode() { 97 return subroutineAddress; 98 } 99 100 /** 101 * Gets the subroutine address. 102 * 103 * @return {@code >= 0;} the subroutine address 104 */ 105 public int getSubroutineAddress() { 106 return subroutineAddress; 107 } 108} 109