net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/flow/UnconditionalFlowInfo.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2003 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.compiler.flow;
  12
  13 import net.sourceforge.phpdt.internal.compiler.impl.Constant;
  14 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  15 import net.sourceforge.phpdt.internal.compiler.lookup.FieldBinding;
  16 import net.sourceforge.phpdt.internal.compiler.lookup.LocalVariableBinding;
  17 import net.sourceforge.phpdt.internal.compiler.lookup.ReferenceBinding;
  18 import net.sourceforge.phpeclipse.internal.compiler.ast.AstNode;
  19 import net.sourceforge.phpeclipse.internal.compiler.ast.Statement;
  20
  21 /**
  22  * Record initialization status during definite assignment analysis
  23  *
  24  * No caching of pre-allocated instances.
  25  */
  26 public class UnconditionalFlowInfo extends FlowInfo {
  27
  28
  29         public long definiteInits;
  30         public long potentialInits;
  31         public long extraDefiniteInits[];
  32         public long extraPotentialInits[];
  33
  34         public int reachMode = REACHABLE; // by default
  35
  36         public int maxFieldCount;
  37
  38         // Constants
  39         public static final int BitCacheSize = 64; // 64 bits in a long.
  40
  41         UnconditionalFlowInfo() {
  42         }
  43
  44         // unions of both sets of initialization - used for try/finally
  45         public FlowInfo addInitializationsFrom(FlowInfo inits) {
  46
  47                 if (this == DEAD_END)
  48                         return this;
  49
  50                 UnconditionalFlowInfo otherInits = inits.unconditionalInits();
  51                 if (otherInits == DEAD_END)
  52                         return this;
  53
  54                 // union of definitely assigned variables,
  55                 definiteInits |= otherInits.definiteInits;
  56                 // union of potentially set ones
  57                 potentialInits |= otherInits.potentialInits;
  58
  59                 // treating extra storage
  60                 if (extraDefiniteInits != null) {
  61                         if (otherInits.extraDefiniteInits != null) {
  62                                 // both sides have extra storage
  63                                 int i = 0, length, otherLength;
  64                                 if ((length = extraDefiniteInits.length) < (otherLength = otherInits.extraDefiniteInits.length)) {
  65                                         // current storage is shorter -> grow current (could maybe reuse otherInits extra storage?)
  66                                         System.arraycopy(extraDefiniteInits, 0, (extraDefiniteInits = new long[otherLength]), 0, length);
  67                                         System.arraycopy(extraPotentialInits, 0, (extraPotentialInits = new long[otherLength]), 0, length);
  68                                         while (i < length) {
  69                                                 extraDefiniteInits[i] |= otherInits.extraDefiniteInits[i];
  70                                                 extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
  71                                         }
  72                                         while (i < otherLength) {
  73                                                 extraPotentialInits[i] = otherInits.extraPotentialInits[i++];
  74                                         }
  75                                 } else {
  76                                         // current storage is longer
  77                                         while (i < otherLength) {
  78                                                 extraDefiniteInits[i] |= otherInits.extraDefiniteInits[i];
  79                                                 extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
  80                                         }
  81                                         while (i < length)
  82                                                 extraDefiniteInits[i++] = 0;
  83                                 }
  84                         } else {
  85                                 // no extra storage on otherInits
  86                         }
  87                 } else
  88                         if (otherInits.extraDefiniteInits != null) {
  89                                 // no storage here, but other has extra storage.
  90                                 int otherLength;
  91                                 System.arraycopy(otherInits.extraDefiniteInits, 0, (extraDefiniteInits = new long[otherLength = otherInits.extraDefiniteInits.length]), 0, otherLength);
  92                                 System.arraycopy(otherInits.extraPotentialInits, 0, (extraPotentialInits = new long[otherLength]), 0, otherLength);
  93                         }
  94                 return this;
  95         }
  96
  97         // unions of both sets of initialization - used for try/finally
  98         public FlowInfo addPotentialInitializationsFrom(FlowInfo inits) {
  99
 100                 if (this == DEAD_END){
 101                         return this;
 102                 }
 103
 104                 UnconditionalFlowInfo otherInits = inits.unconditionalInits();
 105                 if (otherInits == DEAD_END){
 106                         return this;
 107                 }
 108                 // union of potentially set ones
 109                 potentialInits |= otherInits.potentialInits;
 110
 111                 // treating extra storage
 112                 if (extraDefiniteInits != null) {
 113                         if (otherInits.extraDefiniteInits != null) {
 114                                 // both sides have extra storage
 115                                 int i = 0, length, otherLength;
 116                                 if ((length = extraDefiniteInits.length) < (otherLength = otherInits.extraDefiniteInits.length)) {
 117                                         // current storage is shorter -> grow current (could maybe reuse otherInits extra storage?)
 118                                         System.arraycopy(extraDefiniteInits, 0, (extraDefiniteInits = new long[otherLength]), 0, length);
 119                                         System.arraycopy(extraPotentialInits, 0, (extraPotentialInits = new long[otherLength]), 0, length);
 120                                         while (i < length) {
 121                                                 extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
 122                                         }
 123                                         while (i < otherLength) {
 124                                                 extraPotentialInits[i] = otherInits.extraPotentialInits[i++];
 125                                         }
 126                                 } else {
 127                                         // current storage is longer
 128                                         while (i < otherLength) {
 129                                                 extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
 130                                         }
 131                                 }
 132                         }
 133                 } else
 134                         if (otherInits.extraDefiniteInits != null) {
 135                                 // no storage here, but other has extra storage.
 136                                 int otherLength;
 137                                 extraDefiniteInits = new long[otherLength = otherInits.extraDefiniteInits.length];
 138                                 System.arraycopy(otherInits.extraPotentialInits, 0, (extraPotentialInits = new long[otherLength]), 0, otherLength);
 139                         }
 140                 return this;
 141         }
 142
 143         // Report an error if necessary
 144         public boolean complainIfUnreachable(Statement statement, BlockScope scope, boolean didAlreadyComplain) {
 145
 146                 if ((this.reachMode & UNREACHABLE) != 0) {
 147                         statement.bits &= ~AstNode.IsReachableMASK;
 148                         boolean reported = this == DEAD_END;
 149                         if (!didAlreadyComplain && reported) {
 150                                 scope.problemReporter().unreachableCode(statement);
 151                         }
 152                         return reported; // keep going for fake reachable
 153                 }
 154                 return false;
 155         }
 156
 157         /**
 158          * Answers a copy of the current instance
 159          */
 160         public FlowInfo copy() {
 161
 162                 // do not clone the DeadEnd
 163                 if (this == DEAD_END)
 164                         return this;
 165
 166                 // look for an unused preallocated object
 167                 UnconditionalFlowInfo copy = new UnconditionalFlowInfo();
 168
 169                 // copy slots
 170                 copy.definiteInits = this.definiteInits;
 171                 copy.potentialInits = this.potentialInits;
 172                 copy.reachMode = this.reachMode;
 173                 copy.maxFieldCount = this.maxFieldCount;
 174
 175                 if (this.extraDefiniteInits != null) {
 176                         int length;
 177                         System.arraycopy(this.extraDefiniteInits, 0, (copy.extraDefiniteInits = new long[ (length = extraDefiniteInits.length)]), 0, length);
 178                         System.arraycopy(this.extraPotentialInits, 0, (copy.extraPotentialInits = new long[length]), 0, length);
 179                 };
 180                 return copy;
 181         }
 182
 183         public UnconditionalFlowInfo discardFieldInitializations(){
 184
 185                 int limit = this.maxFieldCount;
 186
 187                 if (limit < BitCacheSize) {
 188                         long mask = (1L << limit)-1;
 189                         this.definiteInits &= ~mask;
 190                         this.potentialInits &= ~mask;
 191                         return this;
 192                 }
 193
 194                 this.definiteInits = 0;
 195                 this.potentialInits = 0;
 196
 197                 // use extra vector
 198                 if (extraDefiniteInits == null) {
 199                         return this; // if vector not yet allocated, then not initialized
 200                 }
 201                 int vectorIndex, length = this.extraDefiniteInits.length;
 202                 if ((vectorIndex = (limit / BitCacheSize) - 1) >= length) {
 203                         return this; // not enough room yet
 204                 }
 205                 for (int i = 0; i < vectorIndex; i++) {
 206                         this.extraDefiniteInits[i] = 0L;
 207                         this.extraPotentialInits[i] = 0L;
 208                 }
 209                 long mask = (1L << (limit % BitCacheSize))-1;
 210                 this.extraDefiniteInits[vectorIndex] &= ~mask;
 211                 this.extraPotentialInits[vectorIndex] &= ~mask;
 212                 return this;
 213         }
 214
 215         public UnconditionalFlowInfo discardNonFieldInitializations(){
 216
 217                 int limit = this.maxFieldCount;
 218
 219                 if (limit < BitCacheSize) {
 220                         long mask = (1L << limit)-1;
 221                         this.definiteInits &= mask;
 222                         this.potentialInits &= mask;
 223                         return this;
 224                 }
 225                 // use extra vector
 226                 if (extraDefiniteInits == null) {
 227                         return this; // if vector not yet allocated, then not initialized
 228                 }
 229                 int vectorIndex, length = this.extraDefiniteInits.length;
 230                 if ((vectorIndex = (limit / BitCacheSize) - 1) >= length) {
 231                         return this; // not enough room yet
 232                 }
 233                 long mask = (1L << (limit % BitCacheSize))-1;
 234                 this.extraDefiniteInits[vectorIndex] &= mask;
 235                 this.extraPotentialInits[vectorIndex] &= mask;
 236                 for (int i = vectorIndex+1; i < length; i++) {
 237                         this.extraDefiniteInits[i] = 0L;
 238                         this.extraPotentialInits[i] = 0L;
 239                 }
 240                 return this;
 241         }
 242
 243         public FlowInfo initsWhenFalse() {
 244
 245                 return this;
 246         }
 247
 248         public FlowInfo initsWhenTrue() {
 249
 250                 return this;
 251         }
 252
 253         /**
 254          * Check status of definite assignment at a given position.
 255          * It deals with the dual representation of the InitializationInfo2:
 256          * bits for the first 64 entries, then an array of booleans.
 257          */
 258         final private boolean isDefinitelyAssigned(int position) {
 259
 260                 // Dependant of CodeStream.isDefinitelyAssigned(..)
 261                 // id is zero-based
 262                 if (position < BitCacheSize) {
 263                         return (definiteInits & (1L << position)) != 0; // use bits
 264                 }
 265                 // use extra vector
 266                 if (extraDefiniteInits == null)
 267                         return false; // if vector not yet allocated, then not initialized
 268                 int vectorIndex;
 269                 if ((vectorIndex = (position / BitCacheSize) - 1) >= extraDefiniteInits.length)
 270                         return false; // if not enough room in vector, then not initialized
 271                 return ((extraDefiniteInits[vectorIndex]) & (1L << (position % BitCacheSize))) != 0;
 272         }
 273
 274         /**
 275          * Check status of definite assignment for a field.
 276          */
 277         final public boolean isDefinitelyAssigned(FieldBinding field) {
 278
 279                 // Dependant of CodeStream.isDefinitelyAssigned(..)
 280                 // We do not want to complain in unreachable code
 281                 if ((this.reachMode & UNREACHABLE) != 0)
 282                         return true;
 283                 return isDefinitelyAssigned(field.id);
 284         }
 285
 286         /**
 287          * Check status of definite assignment for a local.
 288          */
 289         final public boolean isDefinitelyAssigned(LocalVariableBinding local) {
 290
 291                 // Dependant of CodeStream.isDefinitelyAssigned(..)
 292                 // We do not want to complain in unreachable code
 293                 if ((this.reachMode & UNREACHABLE) != 0)
 294                         return true;
 295                 if (local.isArgument) {
 296                         return true;
 297                 }
 298                 // final constants are inlined, and thus considered as always initialized
 299                 if (local.constant != Constant.NotAConstant) {
 300                         return true;
 301                 }
 302                 return isDefinitelyAssigned(local.id + maxFieldCount);
 303         }
 304
 305         public boolean isReachable() {
 306
 307                 return this.reachMode == REACHABLE;
 308         }
 309
 310         /**
 311          * Check status of potential assignment at a given position.
 312          * It deals with the dual representation of the InitializationInfo3:
 313          * bits for the first 64 entries, then an array of booleans.
 314          */
 315         final private boolean isPotentiallyAssigned(int position) {
 316
 317                 // id is zero-based
 318                 if (position < BitCacheSize) {
 319                         // use bits
 320                         return (potentialInits & (1L << position)) != 0;
 321                 }
 322                 // use extra vector
 323                 if (extraPotentialInits == null)
 324                         return false; // if vector not yet allocated, then not initialized
 325                 int vectorIndex;
 326                 if ((vectorIndex = (position / BitCacheSize) - 1) >= extraPotentialInits.length)
 327                         return false; // if not enough room in vector, then not initialized
 328                 return ((extraPotentialInits[vectorIndex]) & (1L << (position % BitCacheSize))) != 0;
 329         }
 330
 331         /**
 332          * Check status of definite assignment for a field.
 333          */
 334         final public boolean isPotentiallyAssigned(FieldBinding field) {
 335
 336                 return isPotentiallyAssigned(field.id);
 337         }
 338
 339         /**
 340          * Check status of potential assignment for a local.
 341          */
 342         final public boolean isPotentiallyAssigned(LocalVariableBinding local) {
 343
 344                 if (local.isArgument) {
 345                         return true;
 346                 }
 347                 // final constants are inlined, and thus considered as always initialized
 348                 if (local.constant != Constant.NotAConstant) {
 349                         return true;
 350                 }
 351                 return isPotentiallyAssigned(local.id + maxFieldCount);
 352         }
 353
 354         /**
 355          * Record a definite assignment at a given position.
 356          * It deals with the dual representation of the InitializationInfo2:
 357          * bits for the first 64 entries, then an array of booleans.
 358          */
 359         final private void markAsDefinitelyAssigned(int position) {
 360
 361                 if (this != DEAD_END) {
 362
 363                         // position is zero-based
 364                         if (position < BitCacheSize) {
 365                                 // use bits
 366                                 long mask;
 367                                 definiteInits |= (mask = 1L << position);
 368                                 potentialInits |= mask;
 369                         } else {
 370                                 // use extra vector
 371                                 int vectorIndex = (position / BitCacheSize) - 1;
 372                                 if (extraDefiniteInits == null) {
 373                                         int length;
 374                                         extraDefiniteInits = new long[length = vectorIndex + 1];
 375                                         extraPotentialInits = new long[length];
 376                                 } else {
 377                                         int oldLength; // might need to grow the arrays
 378                                         if (vectorIndex >= (oldLength = extraDefiniteInits.length)) {
 379                                                 System.arraycopy(extraDefiniteInits, 0, (extraDefiniteInits = new long[vectorIndex + 1]), 0, oldLength);
 380                                                 System.arraycopy(extraPotentialInits, 0, (extraPotentialInits = new long[vectorIndex + 1]), 0, oldLength);
 381                                         }
 382                                 }
 383                                 long mask;
 384                                 extraDefiniteInits[vectorIndex] |= (mask = 1L << (position % BitCacheSize));
 385                                 extraPotentialInits[vectorIndex] |= mask;
 386                         }
 387                 }
 388         }
 389
 390         /**
 391          * Record a field got definitely assigned.
 392          */
 393         public void markAsDefinitelyAssigned(FieldBinding field) {
 394                 if (this != DEAD_END)
 395                         markAsDefinitelyAssigned(field.id);
 396         }
 397
 398         /**
 399          * Record a local got definitely assigned.
 400          */
 401         public void markAsDefinitelyAssigned(LocalVariableBinding local) {
 402                 if (this != DEAD_END)
 403                         markAsDefinitelyAssigned(local.id + maxFieldCount);
 404         }
 405
 406         /**
 407          * Clear initialization information at a given position.
 408          * It deals with the dual representation of the InitializationInfo2:
 409          * bits for the first 64 entries, then an array of booleans.
 410          */
 411         final private void markAsDefinitelyNotAssigned(int position) {
 412                 if (this != DEAD_END) {
 413
 414                         // position is zero-based
 415                         if (position < BitCacheSize) {
 416                                 // use bits
 417                                 long mask;
 418                                 definiteInits &= ~(mask = 1L << position);
 419                                 potentialInits &= ~mask;
 420                         } else {
 421                                 // use extra vector
 422                                 int vectorIndex = (position / BitCacheSize) - 1;
 423                                 if (extraDefiniteInits == null) {
 424                                         return; // nothing to do, it was not yet set
 425                                 } else {
 426                                         // might need to grow the arrays
 427                                         if (vectorIndex >= extraDefiniteInits.length) {
 428                                                 return; // nothing to do, it was not yet set
 429                                         }
 430                                 }
 431                                 long mask;
 432                                 extraDefiniteInits[vectorIndex] &= ~(mask = 1L << (position % BitCacheSize));
 433                                 extraPotentialInits[vectorIndex] &= ~mask;
 434                         }
 435                 }
 436         }
 437
 438         /**
 439          * Clear the initialization info for a field
 440          */
 441         public void markAsDefinitelyNotAssigned(FieldBinding field) {
 442
 443                 if (this != DEAD_END)
 444                         markAsDefinitelyNotAssigned(field.id);
 445         }
 446
 447         /**
 448          * Clear the initialization info for a local variable
 449          */
 450
 451         public void markAsDefinitelyNotAssigned(LocalVariableBinding local) {
 452
 453                 if (this != DEAD_END)
 454                         markAsDefinitelyNotAssigned(local.id + maxFieldCount);
 455         }
 456
 457         /**
 458          * Returns the receiver updated in the following way: <ul>
 459          * <li> intersection of definitely assigned variables,
 460          * <li> union of potentially assigned variables.
 461          * </ul>
 462          */
 463         public UnconditionalFlowInfo mergedWith(UnconditionalFlowInfo otherInits) {
 464
 465                 if (this == DEAD_END) return otherInits;
 466                 if (otherInits == DEAD_END) return this;
 467
 468                 if ((this.reachMode & UNREACHABLE) != (otherInits.reachMode & UNREACHABLE)){
 469                         if ((this.reachMode & UNREACHABLE) != 0){
 470                                 return otherInits;
 471                         } else {
 472                                 return this;
 473                         }
 474                 }
 475
 476                 // if one branch is not fake reachable, then the merged one is reachable
 477                 this.reachMode &= otherInits.reachMode;
 478
 479                 // intersection of definitely assigned variables,
 480                 this.definiteInits &= otherInits.definiteInits;
 481                 // union of potentially set ones
 482                 this.potentialInits |= otherInits.potentialInits;
 483
 484                 // treating extra storage
 485                 if (this.extraDefiniteInits != null) {
 486                         if (otherInits.extraDefiniteInits != null) {
 487                                 // both sides have extra storage
 488                                 int i = 0, length, otherLength;
 489                                 if ((length = this.extraDefiniteInits.length) < (otherLength = otherInits.extraDefiniteInits.length)) {
 490                                         // current storage is shorter -> grow current (could maybe reuse otherInits extra storage?)
 491                                         System.arraycopy(this.extraDefiniteInits, 0, (this.extraDefiniteInits = new long[otherLength]), 0, length);
 492                                         System.arraycopy(this.extraPotentialInits, 0, (this.extraPotentialInits = new long[otherLength]), 0, length);
 493                                         while (i < length) {
 494                                                 this.extraDefiniteInits[i] &= otherInits.extraDefiniteInits[i];
 495                                                 this.extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
 496                                         }
 497                                         while (i < otherLength) {
 498                                                 this.extraPotentialInits[i] = otherInits.extraPotentialInits[i++];
 499                                         }
 500                                 } else {
 501                                         // current storage is longer
 502                                         while (i < otherLength) {
 503                                                 this.extraDefiniteInits[i] &= otherInits.extraDefiniteInits[i];
 504                                                 this.extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
 505                                         }
 506                                         while (i < length)
 507                                                 this.extraDefiniteInits[i++] = 0;
 508                                 }
 509                         } else {
 510                                 // no extra storage on otherInits
 511                                 int i = 0, length = this.extraDefiniteInits.length;
 512                                 while (i < length)
 513                                         this.extraDefiniteInits[i++] = 0;
 514                         }
 515                 } else
 516                         if (otherInits.extraDefiniteInits != null) {
 517                                 // no storage here, but other has extra storage.
 518                                 int otherLength;
 519                                 this.extraDefiniteInits = new long[otherLength = otherInits.extraDefiniteInits.length];
 520                                 System.arraycopy(otherInits.extraPotentialInits, 0, (this.extraPotentialInits = new long[otherLength]), 0, otherLength);
 521                         }
 522                 return this;
 523         }
 524
 525         /*
 526          * Answer the total number of fields in enclosing types of a given type
 527          */
 528         static int numberOfEnclosingFields(ReferenceBinding type){
 529
 530                 int count = 0;
 531                 type = type.enclosingType();
 532                 while(type != null) {
 533                         count += type.fieldCount();
 534                         type = type.enclosingType();
 535                 }
 536                 return count;
 537         }
 538
 539         public int reachMode(){
 540                 return this.reachMode;
 541         }
 542
 543         public FlowInfo setReachMode(int reachMode) {
 544
 545                 if (this == DEAD_END) return this; // cannot modify DEAD_END
 546
 547                 // reset optional inits when becoming unreachable
 548                 if ((this.reachMode & UNREACHABLE) == 0 && (reachMode & UNREACHABLE) != 0) {
 549                         this.potentialInits = 0;
 550                         if (this.extraPotentialInits != null){
 551                                 for (int i = 0, length = this.extraPotentialInits.length; i < length; i++){
 552                                         this.extraPotentialInits[i] = 0;
 553                                 }
 554                         }
 555                 }
 556                 this.reachMode = reachMode;
 557
 558                 return this;
 559         }
 560
 561         public String toString(){
 562
 563                 if (this == DEAD_END){
 564                         return "FlowInfo.DEAD_END"; //$NON-NLS-1$
 565                 }
 566                 return "FlowInfo<def: "+ this.definiteInits //$NON-NLS-1$
 567                         +", pot: " + this.potentialInits  //$NON-NLS-1$
 568                         + ", reachable:" + ((this.reachMode & UNREACHABLE) == 0) //$NON-NLS-1$
 569                         +">"; //$NON-NLS-1$
 570         }
 571
 572         public UnconditionalFlowInfo unconditionalInits() {
 573
 574                 // also see conditional inits, where it requests them to merge
 575                 return this;
 576         }
 577 }