001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package org.apache.bcel.classfile; 019 020import java.io.DataInput; 021import java.io.DataOutputStream; 022import java.io.IOException; 023import java.util.Arrays; 024 025import org.apache.bcel.Const; 026 027/** 028 * This class represents a stack map entry recording the types of local variables and the of stack items at a given 029 * byte code offset. See CLDC specification 5.3.1.2. 030 * 031 * See also https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.4 032 * 033 * <pre> 034 * union stack_map_frame { 035 * same_frame; 036 * same_locals_1_stack_item_frame; 037 * same_locals_1_stack_item_frame_extended; 038 * chop_frame; 039 * same_frame_extended; 040 * append_frame; 041 * full_frame; 042 * } 043 * </pre> 044 * @see StackMap 045 * @see StackMapType 046 */ 047public final class StackMapEntry implements Node, Cloneable { 048 049 static final StackMapEntry[] EMPTY_ARRAY = {}; 050 051 private int frameType; 052 private int byteCodeOffset; 053 private StackMapType[] typesOfLocals; 054 private StackMapType[] typesOfStackItems; 055 private ConstantPool constantPool; 056 057 /** 058 * Constructs object from input stream. 059 * 060 * @param dataInput Input stream 061 * @throws IOException if an I/O error occurs. 062 */ 063 StackMapEntry(final DataInput dataInput, final ConstantPool constantPool) throws IOException { 064 this(dataInput.readByte() & 0xFF, -1, null, null, constantPool); 065 066 if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) { 067 byteCodeOffset = frameType - Const.SAME_FRAME; 068 } else if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) { 069 byteCodeOffset = frameType - Const.SAME_LOCALS_1_STACK_ITEM_FRAME; 070 typesOfStackItems = new StackMapType[] { new StackMapType(dataInput, constantPool) }; 071 } else if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) { 072 byteCodeOffset = dataInput.readUnsignedShort(); 073 typesOfStackItems = new StackMapType[] { new StackMapType(dataInput, constantPool) }; 074 } else if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX || frameType == Const.SAME_FRAME_EXTENDED) { 075 byteCodeOffset = dataInput.readUnsignedShort(); 076 } else if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) { 077 byteCodeOffset = dataInput.readUnsignedShort(); 078 final int numberOfLocals = frameType - 251; 079 typesOfLocals = new StackMapType[numberOfLocals]; 080 for (int i = 0; i < numberOfLocals; i++) { 081 typesOfLocals[i] = new StackMapType(dataInput, constantPool); 082 } 083 } else if (frameType == Const.FULL_FRAME) { 084 byteCodeOffset = dataInput.readUnsignedShort(); 085 final int numberOfLocals = dataInput.readUnsignedShort(); 086 typesOfLocals = new StackMapType[numberOfLocals]; 087 for (int i = 0; i < numberOfLocals; i++) { 088 typesOfLocals[i] = new StackMapType(dataInput, constantPool); 089 } 090 final int numberOfStackItems = dataInput.readUnsignedShort(); 091 typesOfStackItems = new StackMapType[numberOfStackItems]; 092 for (int i = 0; i < numberOfStackItems; i++) { 093 typesOfStackItems[i] = new StackMapType(dataInput, constantPool); 094 } 095 } else { 096 /* Can't happen */ 097 throw new ClassFormatException("Invalid frame type found while parsing stack map table: " + frameType); 098 } 099 } 100 101 /** 102 * DO NOT USE 103 * 104 * @param byteCodeOffset 105 * @param numberOfLocals NOT USED 106 * @param typesOfLocals array of {@link StackMapType}s of locals 107 * @param numberOfStackItems NOT USED 108 * @param typesOfStackItems array ot {@link StackMapType}s of stack items 109 * @param constantPool the constant pool 110 * @deprecated Since 6.0, use {@link #StackMapEntry(int, int, StackMapType[], StackMapType[], ConstantPool)} instead 111 */ 112 @java.lang.Deprecated 113 public StackMapEntry(final int byteCodeOffset, final int numberOfLocals, final StackMapType[] typesOfLocals, final int numberOfStackItems, 114 final StackMapType[] typesOfStackItems, final ConstantPool constantPool) { 115 this.byteCodeOffset = byteCodeOffset; 116 this.typesOfLocals = typesOfLocals != null ? typesOfLocals : StackMapType.EMPTY_ARRAY; 117 this.typesOfStackItems = typesOfStackItems != null ? typesOfStackItems : StackMapType.EMPTY_ARRAY; 118 this.constantPool = constantPool; 119 if (numberOfLocals < 0) { 120 throw new IllegalArgumentException("numberOfLocals < 0"); 121 } 122 if (numberOfStackItems < 0) { 123 throw new IllegalArgumentException("numberOfStackItems < 0"); 124 } 125 } 126 127 /** 128 * Create an instance 129 * 130 * @param tag the frameType to use 131 * @param byteCodeOffset 132 * @param typesOfLocals array of {@link StackMapType}s of locals 133 * @param typesOfStackItems array ot {@link StackMapType}s of stack items 134 * @param constantPool the constant pool 135 */ 136 public StackMapEntry(final int tag, final int byteCodeOffset, final StackMapType[] typesOfLocals, final StackMapType[] typesOfStackItems, 137 final ConstantPool constantPool) { 138 this.frameType = tag; 139 this.byteCodeOffset = byteCodeOffset; 140 this.typesOfLocals = typesOfLocals != null ? typesOfLocals : StackMapType.EMPTY_ARRAY; 141 this.typesOfStackItems = typesOfStackItems != null ? typesOfStackItems : StackMapType.EMPTY_ARRAY; 142 this.constantPool = constantPool; 143 } 144 145 /** 146 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. 147 * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects. 148 * 149 * @param v Visitor object 150 */ 151 @Override 152 public void accept(final Visitor v) { 153 v.visitStackMapEntry(this); 154 } 155 156 /** 157 * @return deep copy of this object 158 */ 159 public StackMapEntry copy() { 160 StackMapEntry e; 161 try { 162 e = (StackMapEntry) clone(); 163 } catch (final CloneNotSupportedException ex) { 164 throw new UnsupportedOperationException("Clone Not Supported", ex); 165 } 166 167 e.typesOfLocals = new StackMapType[typesOfLocals.length]; 168 Arrays.setAll(e.typesOfLocals, i -> typesOfLocals[i].copy()); 169 e.typesOfStackItems = new StackMapType[typesOfStackItems.length]; 170 Arrays.setAll(e.typesOfStackItems, i -> typesOfStackItems[i].copy()); 171 return e; 172 } 173 174 /** 175 * Dump stack map entry 176 * 177 * @param file Output file stream 178 * @throws IOException if an I/O error occurs. 179 */ 180 public void dump(final DataOutputStream file) throws IOException { 181 file.write(frameType); 182 if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) { 183 typesOfStackItems[0].dump(file); 184 } else if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) { 185 file.writeShort(byteCodeOffset); 186 typesOfStackItems[0].dump(file); 187 } else if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX || frameType == Const.SAME_FRAME_EXTENDED) { 188 file.writeShort(byteCodeOffset); 189 } else if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) { 190 file.writeShort(byteCodeOffset); 191 for (final StackMapType type : typesOfLocals) { 192 type.dump(file); 193 } 194 } else if (frameType == Const.FULL_FRAME) { 195 file.writeShort(byteCodeOffset); 196 file.writeShort(typesOfLocals.length); 197 for (final StackMapType type : typesOfLocals) { 198 type.dump(file); 199 } 200 file.writeShort(typesOfStackItems.length); 201 for (final StackMapType type : typesOfStackItems) { 202 type.dump(file); 203 } 204 } else if (!(frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX)) { 205 /* Can't happen */ 206 throw new ClassFormatException("Invalid Stack map table tag: " + frameType); 207 } 208 } 209 210 public int getByteCodeOffset() { 211 return byteCodeOffset; 212 } 213 214 /** 215 * @return Constant pool used by this object. 216 */ 217 public ConstantPool getConstantPool() { 218 return constantPool; 219 } 220 221 public int getFrameType() { 222 return frameType; 223 } 224 225 /** 226 * Calculate stack map entry size 227 * 228 */ 229 int getMapEntrySize() { 230 if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) { 231 return 1; 232 } 233 if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) { 234 return 1 + (typesOfStackItems[0].hasIndex() ? 3 : 1); 235 } 236 if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) { 237 return 3 + (typesOfStackItems[0].hasIndex() ? 3 : 1); 238 } 239 if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX || frameType == Const.SAME_FRAME_EXTENDED) { 240 return 3; 241 } 242 if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) { 243 int len = 3; 244 for (final StackMapType typesOfLocal : typesOfLocals) { 245 len += typesOfLocal.hasIndex() ? 3 : 1; 246 } 247 return len; 248 } 249 if (frameType != Const.FULL_FRAME) { 250 throw new IllegalStateException("Invalid StackMap frameType: " + frameType); 251 } 252 int len = 7; 253 for (final StackMapType typesOfLocal : typesOfLocals) { 254 len += typesOfLocal.hasIndex() ? 3 : 1; 255 } 256 for (final StackMapType typesOfStackItem : typesOfStackItems) { 257 len += typesOfStackItem.hasIndex() ? 3 : 1; 258 } 259 return len; 260 } 261 262 public int getNumberOfLocals() { 263 return typesOfLocals.length; 264 } 265 266 public int getNumberOfStackItems() { 267 return typesOfStackItems.length; 268 } 269 270 public StackMapType[] getTypesOfLocals() { 271 return typesOfLocals; 272 } 273 274 public StackMapType[] getTypesOfStackItems() { 275 return typesOfStackItems; 276 } 277 278 private boolean invalidFrameType(final int f) { 279 // @formatter:off 280 return f != Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED 281 && !(f >= Const.CHOP_FRAME && f <= Const.CHOP_FRAME_MAX) 282 && f != Const.SAME_FRAME_EXTENDED 283 && !(f >= Const.APPEND_FRAME && f <= Const.APPEND_FRAME_MAX) 284 && f != Const.FULL_FRAME; 285 // @formatter:on 286 } 287 288 public void setByteCodeOffset(final int newOffset) { 289 if (newOffset < 0 || newOffset > 32767) { 290 throw new IllegalArgumentException("Invalid StackMap offset: " + newOffset); 291 } 292 293 if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) { 294 if (newOffset > Const.SAME_FRAME_MAX) { 295 frameType = Const.SAME_FRAME_EXTENDED; 296 } else { 297 frameType = newOffset; 298 } 299 } else if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) { 300 if (newOffset > Const.SAME_FRAME_MAX) { 301 frameType = Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED; 302 } else { 303 frameType = Const.SAME_LOCALS_1_STACK_ITEM_FRAME + newOffset; 304 } 305 } else if (invalidFrameType(frameType)) { 306 throw new IllegalStateException("Invalid StackMap frameType: " + frameType); 307 } 308 byteCodeOffset = newOffset; 309 } 310 311 /** 312 * @param constantPool Constant pool to be used for this object. 313 */ 314 public void setConstantPool(final ConstantPool constantPool) { 315 this.constantPool = constantPool; 316 } 317 318 public void setFrameType(final int ft) { 319 if (ft >= Const.SAME_FRAME && ft <= Const.SAME_FRAME_MAX) { 320 byteCodeOffset = ft - Const.SAME_FRAME; 321 } else if (ft >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && ft <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) { 322 byteCodeOffset = ft - Const.SAME_LOCALS_1_STACK_ITEM_FRAME; 323 } else if (invalidFrameType(ft)) { 324 throw new IllegalArgumentException("Invalid StackMap frameType"); 325 } 326 frameType = ft; 327 } 328 329 /** 330 * 331 * @deprecated since 6.0 332 */ 333 @java.lang.Deprecated 334 public void setNumberOfLocals(final int n) { // TODO unused 335 } 336 337 /** 338 * 339 * @deprecated since 6.0 340 */ 341 @java.lang.Deprecated 342 public void setNumberOfStackItems(final int n) { // TODO unused 343 } 344 345 public void setTypesOfLocals(final StackMapType[] types) { 346 typesOfLocals = types != null ? types : StackMapType.EMPTY_ARRAY; 347 } 348 349 public void setTypesOfStackItems(final StackMapType[] types) { 350 typesOfStackItems = types != null ? types : StackMapType.EMPTY_ARRAY; 351 } 352 353 /** 354 * @return String representation. 355 */ 356 @Override 357 public String toString() { 358 final StringBuilder buf = new StringBuilder(64); 359 buf.append("("); 360 if (frameType >= Const.SAME_FRAME && frameType <= Const.SAME_FRAME_MAX) { 361 buf.append("SAME"); 362 } else if (frameType >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME && frameType <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_MAX) { 363 buf.append("SAME_LOCALS_1_STACK"); 364 } else if (frameType == Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) { 365 buf.append("SAME_LOCALS_1_STACK_EXTENDED"); 366 } else if (frameType >= Const.CHOP_FRAME && frameType <= Const.CHOP_FRAME_MAX) { 367 buf.append("CHOP ").append(String.valueOf(251 - frameType)); 368 } else if (frameType == Const.SAME_FRAME_EXTENDED) { 369 buf.append("SAME_EXTENDED"); 370 } else if (frameType >= Const.APPEND_FRAME && frameType <= Const.APPEND_FRAME_MAX) { 371 buf.append("APPEND ").append(String.valueOf(frameType - 251)); 372 } else if (frameType == Const.FULL_FRAME) { 373 buf.append("FULL"); 374 } else { 375 buf.append("UNKNOWN (").append(frameType).append(")"); 376 } 377 buf.append(", offset delta=").append(byteCodeOffset); 378 if (typesOfLocals.length > 0) { 379 buf.append(", locals={"); 380 for (int i = 0; i < typesOfLocals.length; i++) { 381 buf.append(typesOfLocals[i]); 382 if (i < typesOfLocals.length - 1) { 383 buf.append(", "); 384 } 385 } 386 buf.append("}"); 387 } 388 if (typesOfStackItems.length > 0) { 389 buf.append(", stack items={"); 390 for (int i = 0; i < typesOfStackItems.length; i++) { 391 buf.append(typesOfStackItems[i]); 392 if (i < typesOfStackItems.length - 1) { 393 buf.append(", "); 394 } 395 } 396 buf.append("}"); 397 } 398 buf.append(")"); 399 return buf.toString(); 400 } 401 402 /** 403 * Update the distance (as an offset delta) from this StackMap entry to the next. Note that this might cause the 404 * frame type to change. Note also that delta may be negative. 405 * 406 * @param delta offset delta 407 */ 408 public void updateByteCodeOffset(final int delta) { 409 setByteCodeOffset(byteCodeOffset + delta); 410 } 411}