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.cf.code; 18 19 import com.android.dex.util.ExceptionWithContext; 20 import com.android.dx.rop.code.RegisterSpec; 21 import com.android.dx.rop.type.Type; 22 import com.android.dx.rop.type.TypeBearer; 23 import com.android.dx.util.MutabilityControl; 24 import com.android.dx.util.ToHuman; 25 26 /** 27 * Representation of an array of local variables, with Java semantics. 28 * 29 * <p><b>Note:</b> For the most part, the documentation for this class 30 * ignores the distinction between {@link Type} and {@link 31 * TypeBearer}.</p> 32 */ 33 public abstract class LocalsArray extends MutabilityControl implements ToHuman { 34 35 /** 36 * Constructs an instance, explicitly indicating the mutability. 37 * 38 * @param mutable {@code true} if this instance is mutable 39 */ 40 protected LocalsArray(boolean mutable) { 41 super(mutable); 42 } 43 44 /** 45 * Makes and returns a mutable copy of this instance. 46 * 47 * @return {@code non-null;} the copy 48 */ 49 public abstract LocalsArray copy(); 50 51 /** 52 * Annotates (adds context to) the given exception with information 53 * about this instance. 54 * 55 * @param ex {@code non-null;} the exception to annotate 56 */ 57 public abstract void annotate(ExceptionWithContext ex); 58 59 /** 60 * Replaces all the occurrences of the given uninitialized type in 61 * this array with its initialized equivalent. 62 * 63 * @param type {@code non-null;} type to replace 64 */ 65 public abstract void makeInitialized(Type type); 66 67 /** 68 * Gets the maximum number of locals this instance can refer to. 69 * 70 * @return the max locals 71 */ 72 public abstract int getMaxLocals(); 73 74 /** 75 * Sets the type stored at the given local index. If the given type 76 * is category-2, then (a) the index must be at least two less than 77 * {@link #getMaxLocals} and (b) the next index gets invalidated 78 * by the operation. In case of either category, if the <i>previous</i> 79 * local contains a category-2 value, then it too is invalidated by 80 * this operation. 81 * 82 * @param idx {@code >= 0, < getMaxLocals();} which local 83 * @param type {@code non-null;} new type for the local at {@code idx} 84 */ 85 public abstract void set(int idx, TypeBearer type); 86 87 /** 88 * Sets the type for the local indicated by the given register spec 89 * to that register spec (which includes type and optional name 90 * information). This is identical to calling 91 * {@code set(spec.getReg(), spec)}. 92 * 93 * @param spec {@code non-null;} register spec to use as the basis for the update 94 */ 95 public abstract void set(RegisterSpec spec); 96 97 /** 98 * Invalidates the local at the given index. 99 * 100 * @param idx {@code >= 0, < getMaxLocals();} which local 101 */ 102 public abstract void invalidate(int idx); 103 104 /** 105 * Gets the type stored at the given local index, or {@code null} 106 * if the given local is uninitialized / invalid. 107 * 108 * @param idx {@code >= 0, < getMaxLocals();} which local 109 * @return {@code null-ok;} the type of value stored in that local 110 */ 111 public abstract TypeBearer getOrNull(int idx); 112 113 /** 114 * Gets the type stored at the given local index, only succeeding if 115 * the given local contains a valid type (though it is allowed to 116 * be an uninitialized instance). 117 * 118 * @param idx {@code >= 0, < getMaxLocals();} which local 119 * @return {@code non-null;} the type of value stored in that local 120 * @throws SimException thrown if {@code idx} is valid, but 121 * the contents are invalid 122 */ 123 public abstract TypeBearer get(int idx); 124 125 /** 126 * Gets the type stored at the given local index, which is expected 127 * to be an initialized category-1 value. 128 * 129 * @param idx {@code >= 0, < getMaxLocals();} which local 130 * @return {@code non-null;} the type of value stored in that local 131 * @throws SimException thrown if {@code idx} is valid, but 132 * one of the following holds: (a) the local is invalid; (b) the local 133 * contains an uninitialized instance; (c) the local contains a 134 * category-2 value 135 */ 136 public abstract TypeBearer getCategory1(int idx); 137 138 /** 139 * Gets the type stored at the given local index, which is expected 140 * to be a category-2 value. 141 * 142 * @param idx {@code >= 0, < getMaxLocals();} which local 143 * @return {@code non-null;} the type of value stored in that local 144 * @throws SimException thrown if {@code idx} is valid, but 145 * one of the following holds: (a) the local is invalid; (b) the local 146 * contains a category-1 value 147 */ 148 public abstract TypeBearer getCategory2(int idx); 149 150 /** 151 * Merges this instance with {@code other}. If the merged result is 152 * the same as this instance, then this is returned (not a copy). 153 * 154 * @param other {@code non-null;} another LocalsArray 155 * @return {@code non-null;} the merge result, a new instance or this 156 */ 157 public abstract LocalsArray merge(LocalsArray other); 158 159 /** 160 * Merges this instance with a {@code LocalsSet} from a subroutine 161 * caller. To be used when merging in the first block of a subroutine. 162 * 163 * @param other {@code other non-null;} another LocalsArray. The final locals 164 * state of a subroutine caller. 165 * @param predLabel the label of the subroutine caller block. 166 * @return {@code non-null;} the merge result, a new instance or this 167 */ 168 public abstract LocalsArraySet mergeWithSubroutineCaller 169 (LocalsArray other, int predLabel); 170 171 /** 172 * Gets the locals set appropriate for the current execution context. 173 * That is, if this is a {@code OneLocalsArray} instance, then return 174 * {@code this}, otherwise return {@code LocalsArraySet}'s 175 * primary. 176 * 177 * @return locals for this execution context. 178 */ 179 protected abstract OneLocalsArray getPrimary(); 180 181 } 182
