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.FieldBinding;
  15 import net.sourceforge.phpdt.internal.compiler.lookup.LocalVariableBinding;
  16 import net.sourceforge.phpdt.internal.compiler.lookup.ReferenceBinding;
  17
  18 /**
  19  * Record initialization status during definite assignment analysis
  20  *
  21  * No caching of pre-allocated instances.
  22  */
  23 public class UnconditionalFlowInfo extends FlowInfo {
  24
  25         public long definiteInits;
  26
  27         public long potentialInits;
  28
  29         public long extraDefiniteInits[];
  30
  31         public long extraPotentialInits[];
  32
  33         public int reachMode = REACHABLE; // by default
  34
  35         public int maxFieldCount;
  36
  37         // Constants
  38         public static final int BitCacheSize = 64; // 64 bits in a long.
  39
  40         UnconditionalFlowInfo() {
  41         }
  42
  43         // unions of both sets of initialization - used for try/finally
  44         public FlowInfo addInitializationsFrom(FlowInfo inits) {
  45
  46                 if (this == DEAD_END)
  47                         return this;
  48
  49                 UnconditionalFlowInfo otherInits = inits.unconditionalInits();
  50                 if (otherInits == DEAD_END)
  51                         return this;
  52
  53                 // union of definitely assigned variables,
  54                 definiteInits |= otherInits.definiteInits;
  55                 // union of potentially set ones
  56                 potentialInits |= otherInits.potentialInits;
  57
  58                 // treating extra storage
  59                 if (extraDefiniteInits != null) {
  60                         if (otherInits.extraDefiniteInits != null) {
  61                                 // both sides have extra storage
  62                                 int i = 0, length, otherLength;
  63                                 if ((length = extraDefiniteInits.length) < (otherLength = otherInits.extraDefiniteInits.length)) {
  64                                         // current storage is shorter -> grow current (could maybe
  65                                         // reuse otherInits extra storage?)
  66                                         System.arraycopy(extraDefiniteInits, 0,
  67                                                         (extraDefiniteInits = new long[otherLength]), 0,
  68                                                         length);
  69                                         System.arraycopy(extraPotentialInits, 0,
  70                                                         (extraPotentialInits = new long[otherLength]), 0,
  71                                                         length);
  72                                         while (i < length) {
  73                                                 extraDefiniteInits[i] |= otherInits.extraDefiniteInits[i];
  74                                                 extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
  75                                         }
  76                                         while (i < otherLength) {
  77                                                 extraPotentialInits[i] = otherInits.extraPotentialInits[i++];
  78                                         }
  79                                 } else {
  80                                         // current storage is longer
  81                                         while (i < otherLength) {
  82                                                 extraDefiniteInits[i] |= otherInits.extraDefiniteInits[i];
  83                                                 extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
  84                                         }
  85                                         while (i < length)
  86                                                 extraDefiniteInits[i++] = 0;
  87                                 }
  88                         } else {
  89                                 // no extra storage on otherInits
  90                         }
  91                 } else if (otherInits.extraDefiniteInits != null) {
  92                         // no storage here, but other has extra storage.
  93                         int otherLength;
  94                         System
  95                                         .arraycopy(
  96                                                         otherInits.extraDefiniteInits,
  97                                                         0,
  98                                                         (extraDefiniteInits = new long[otherLength = otherInits.extraDefiniteInits.length]),
  99                                                         0, otherLength);
 100                         System.arraycopy(otherInits.extraPotentialInits, 0,
 101                                         (extraPotentialInits = new long[otherLength]), 0,
 102                                         otherLength);
 103                 }
 104                 return this;
 105         }
 106
 107         // unions of both sets of initialization - used for try/finally
 108         public FlowInfo addPotentialInitializationsFrom(FlowInfo inits) {
 109
 110                 if (this == DEAD_END) {
 111                         return this;
 112                 }
 113
 114                 UnconditionalFlowInfo otherInits = inits.unconditionalInits();
 115                 if (otherInits == DEAD_END) {
 116                         return this;
 117                 }
 118                 // union of potentially set ones
 119                 potentialInits |= otherInits.potentialInits;
 120
 121                 // treating extra storage
 122                 if (extraDefiniteInits != null) {
 123                         if (otherInits.extraDefiniteInits != null) {
 124                                 // both sides have extra storage
 125                                 int i = 0, length, otherLength;
 126                                 if ((length = extraDefiniteInits.length) < (otherLength = otherInits.extraDefiniteInits.length)) {
 127                                         // current storage is shorter -> grow current (could maybe
 128                                         // reuse otherInits extra storage?)
 129                                         System.arraycopy(extraDefiniteInits, 0,
 130                                                         (extraDefiniteInits = new long[otherLength]), 0,
 131                                                         length);
 132                                         System.arraycopy(extraPotentialInits, 0,
 133                                                         (extraPotentialInits = new long[otherLength]), 0,
 134                                                         length);
 135                                         while (i < length) {
 136                                                 extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
 137                                         }
 138                                         while (i < otherLength) {
 139                                                 extraPotentialInits[i] = otherInits.extraPotentialInits[i++];
 140                                         }
 141                                 } else {
 142                                         // current storage is longer
 143                                         while (i < otherLength) {
 144                                                 extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
 145                                         }
 146                                 }
 147                         }
 148                 } else if (otherInits.extraDefiniteInits != null) {
 149                         // no storage here, but other has extra storage.
 150                         int otherLength;
 151                         extraDefiniteInits = new long[otherLength = otherInits.extraDefiniteInits.length];
 152                         System.arraycopy(otherInits.extraPotentialInits, 0,
 153                                         (extraPotentialInits = new long[otherLength]), 0,
 154                                         otherLength);
 155                 }
 156                 return this;
 157         }
 158
 159         // Report an error if necessary
 160         // public boolean complainIfUnreachable(Statement statement, BlockScope
 161         // scope, boolean didAlreadyComplain) {
 162         //
 163         // if ((this.reachMode & UNREACHABLE) != 0) {
 164         // statement.bits &= ~ASTNode.IsReachableMASK;
 165         // boolean reported = this == DEAD_END;
 166         // if (!didAlreadyComplain && reported) {
 167         // scope.problemReporter().unreachableCode(statement);
 168         // }
 169         // return reported; // keep going for fake reachable
 170         // }
 171         // return false;
 172         // }
 173
 174         /**
 175          * Answers a copy of the current instance
 176          */
 177         public FlowInfo copy() {
 178
 179                 // do not clone the DeadEnd
 180                 if (this == DEAD_END)
 181                         return this;
 182
 183                 // look for an unused preallocated object
 184                 UnconditionalFlowInfo copy = new UnconditionalFlowInfo();
 185
 186                 // copy slots
 187                 copy.definiteInits = this.definiteInits;
 188                 copy.potentialInits = this.potentialInits;
 189                 copy.reachMode = this.reachMode;
 190                 copy.maxFieldCount = this.maxFieldCount;
 191
 192                 if (this.extraDefiniteInits != null) {
 193                         int length;
 194                         System
 195                                         .arraycopy(
 196                                                         this.extraDefiniteInits,
 197                                                         0,
 198                                                         (copy.extraDefiniteInits = new long[(length = extraDefiniteInits.length)]),
 199                                                         0, length);
 200                         System.arraycopy(this.extraPotentialInits, 0,
 201                                         (copy.extraPotentialInits = new long[length]), 0, length);
 202                 }
 203                 ;
 204                 return copy;
 205         }
 206
 207         public UnconditionalFlowInfo discardFieldInitializations() {
 208
 209                 int limit = this.maxFieldCount;
 210
 211                 if (limit < BitCacheSize) {
 212                         long mask = (1L << limit) - 1;
 213                         this.definiteInits &= ~mask;
 214                         this.potentialInits &= ~mask;
 215                         return this;
 216                 }
 217
 218                 this.definiteInits = 0;
 219                 this.potentialInits = 0;
 220
 221                 // use extra vector
 222                 if (extraDefiniteInits == null) {
 223                         return this; // if vector not yet allocated, then not initialized
 224                 }
 225                 int vectorIndex, length = this.extraDefiniteInits.length;
 226                 if ((vectorIndex = (limit / BitCacheSize) - 1) >= length) {
 227                         return this; // not enough room yet
 228                 }
 229                 for (int i = 0; i < vectorIndex; i++) {
 230                         this.extraDefiniteInits[i] = 0L;
 231                         this.extraPotentialInits[i] = 0L;
 232                 }
 233                 long mask = (1L << (limit % BitCacheSize)) - 1;
 234                 this.extraDefiniteInits[vectorIndex] &= ~mask;
 235                 this.extraPotentialInits[vectorIndex] &= ~mask;
 236                 return this;
 237         }
 238
 239         public UnconditionalFlowInfo discardNonFieldInitializations() {
 240
 241                 int limit = this.maxFieldCount;
 242
 243                 if (limit < BitCacheSize) {
 244                         long mask = (1L << limit) - 1;
 245                         this.definiteInits &= mask;
 246                         this.potentialInits &= mask;
 247                         return this;
 248                 }
 249                 // use extra vector
 250                 if (extraDefiniteInits == null) {
 251                         return this; // if vector not yet allocated, then not initialized
 252                 }
 253                 int vectorIndex, length = this.extraDefiniteInits.length;
 254                 if ((vectorIndex = (limit / BitCacheSize) - 1) >= length) {
 255                         return this; // not enough room yet
 256                 }
 257                 long mask = (1L << (limit % BitCacheSize)) - 1;
 258                 this.extraDefiniteInits[vectorIndex] &= mask;
 259                 this.extraPotentialInits[vectorIndex] &= mask;
 260                 for (int i = vectorIndex + 1; i < length; i++) {
 261                         this.extraDefiniteInits[i] = 0L;
 262                         this.extraPotentialInits[i] = 0L;
 263                 }
 264                 return this;
 265         }
 266
 267         public FlowInfo initsWhenFalse() {
 268
 269                 return this;
 270         }
 271
 272         public FlowInfo initsWhenTrue() {
 273
 274                 return this;
 275         }
 276
 277         /**
 278          * Check status of definite assignment at a given position. It deals with
 279          * the dual representation of the InitializationInfo2: bits for the first 64
 280          * entries, then an array of booleans.
 281          */
 282         final private boolean isDefinitelyAssigned(int position) {
 283
 284                 // Dependant of CodeStream.isDefinitelyAssigned(..)
 285                 // id is zero-based
 286                 if (position < BitCacheSize) {
 287                         return (definiteInits & (1L << position)) != 0; // use bits
 288                 }
 289                 // use extra vector
 290                 if (extraDefiniteInits == null)
 291                         return false; // if vector not yet allocated, then not initialized
 292                 int vectorIndex;
 293                 if ((vectorIndex = (position / BitCacheSize) - 1) >= extraDefiniteInits.length)
 294                         return false; // if not enough room in vector, then not
 295                                                         // initialized
 296                 return ((extraDefiniteInits[vectorIndex]) & (1L << (position % BitCacheSize))) != 0;
 297         }
 298
 299         /**
 300          * Check status of definite assignment for a field.
 301          */
 302         final public boolean isDefinitelyAssigned(FieldBinding field) {
 303
 304                 // Dependant of CodeStream.isDefinitelyAssigned(..)
 305                 // We do not want to complain in unreachable code
 306                 if ((this.reachMode & UNREACHABLE) != 0)
 307                         return true;
 308                 return isDefinitelyAssigned(field.id);
 309         }
 310
 311         /**
 312          * Check status of definite assignment for a local.
 313          */
 314         final public boolean isDefinitelyAssigned(LocalVariableBinding local) {
 315
 316                 // Dependant of CodeStream.isDefinitelyAssigned(..)
 317                 // We do not want to complain in unreachable code
 318                 if ((this.reachMode & UNREACHABLE) != 0)
 319                         return true;
 320                 if (local.isArgument) {
 321                         return true;
 322                 }
 323                 // final constants are inlined, and thus considered as always
 324                 // initialized
 325                 if (local.constant != Constant.NotAConstant) {
 326                         return true;
 327                 }
 328                 return isDefinitelyAssigned(local.id + maxFieldCount);
 329         }
 330
 331         public boolean isReachable() {
 332
 333                 return this.reachMode == REACHABLE;
 334         }
 335
 336         /**
 337          * Check status of potential assignment at a given position. It deals with
 338          * the dual representation of the InitializationInfo3: bits for the first 64
 339          * entries, then an array of booleans.
 340          */
 341         final private boolean isPotentiallyAssigned(int position) {
 342
 343                 // id is zero-based
 344                 if (position < BitCacheSize) {
 345                         // use bits
 346                         return (potentialInits & (1L << position)) != 0;
 347                 }
 348                 // use extra vector
 349                 if (extraPotentialInits == null)
 350                         return false; // if vector not yet allocated, then not initialized
 351                 int vectorIndex;
 352                 if ((vectorIndex = (position / BitCacheSize) - 1) >= extraPotentialInits.length)
 353                         return false; // if not enough room in vector, then not
 354                                                         // initialized
 355                 return ((extraPotentialInits[vectorIndex]) & (1L << (position % BitCacheSize))) != 0;
 356         }
 357
 358         /**
 359          * Check status of definite assignment for a field.
 360          */
 361         final public boolean isPotentiallyAssigned(FieldBinding field) {
 362
 363                 return isPotentiallyAssigned(field.id);
 364         }
 365
 366         /**
 367          * Check status of potential assignment for a local.
 368          */
 369         final public boolean isPotentiallyAssigned(LocalVariableBinding local) {
 370
 371                 if (local.isArgument) {
 372                         return true;
 373                 }
 374                 // final constants are inlined, and thus considered as always
 375                 // initialized
 376                 if (local.constant != Constant.NotAConstant) {
 377                         return true;
 378                 }
 379                 return isPotentiallyAssigned(local.id + maxFieldCount);
 380         }
 381
 382         /**
 383          * Record a definite assignment at a given position. It deals with the dual
 384          * representation of the InitializationInfo2: bits for the first 64 entries,
 385          * then an array of booleans.
 386          */
 387         final private void markAsDefinitelyAssigned(int position) {
 388
 389                 if (this != DEAD_END) {
 390
 391                         // position is zero-based
 392                         if (position < BitCacheSize) {
 393                                 // use bits
 394                                 long mask;
 395                                 definiteInits |= (mask = 1L << position);
 396                                 potentialInits |= mask;
 397                         } else {
 398                                 // use extra vector
 399                                 int vectorIndex = (position / BitCacheSize) - 1;
 400                                 if (extraDefiniteInits == null) {
 401                                         int length;
 402                                         extraDefiniteInits = new long[length = vectorIndex + 1];
 403                                         extraPotentialInits = new long[length];
 404                                 } else {
 405                                         int oldLength; // might need to grow the arrays
 406                                         if (vectorIndex >= (oldLength = extraDefiniteInits.length)) {
 407                                                 System
 408                                                                 .arraycopy(
 409                                                                                 extraDefiniteInits,
 410                                                                                 0,
 411                                                                                 (extraDefiniteInits = new long[vectorIndex + 1]),
 412                                                                                 0, oldLength);
 413                                                 System
 414                                                                 .arraycopy(
 415                                                                                 extraPotentialInits,
 416                                                                                 0,
 417                                                                                 (extraPotentialInits = new long[vectorIndex + 1]),
 418                                                                                 0, oldLength);
 419                                         }
 420                                 }
 421                                 long mask;
 422                                 extraDefiniteInits[vectorIndex] |= (mask = 1L << (position % BitCacheSize));
 423                                 extraPotentialInits[vectorIndex] |= mask;
 424                         }
 425                 }
 426         }
 427
 428         /**
 429          * Record a field got definitely assigned.
 430          */
 431         public void markAsDefinitelyAssigned(FieldBinding field) {
 432                 if (this != DEAD_END)
 433                         markAsDefinitelyAssigned(field.id);
 434         }
 435
 436         /**
 437          * Record a local got definitely assigned.
 438          */
 439         public void markAsDefinitelyAssigned(LocalVariableBinding local) {
 440                 if (this != DEAD_END)
 441                         markAsDefinitelyAssigned(local.id + maxFieldCount);
 442         }
 443
 444         /**
 445          * Clear initialization information at a given position. It deals with the
 446          * dual representation of the InitializationInfo2: bits for the first 64
 447          * entries, then an array of booleans.
 448          */
 449         final private void markAsDefinitelyNotAssigned(int position) {
 450                 if (this != DEAD_END) {
 451
 452                         // position is zero-based
 453                         if (position < BitCacheSize) {
 454                                 // use bits
 455                                 long mask;
 456                                 definiteInits &= ~(mask = 1L << position);
 457                                 potentialInits &= ~mask;
 458                         } else {
 459                                 // use extra vector
 460                                 int vectorIndex = (position / BitCacheSize) - 1;
 461                                 if (extraDefiniteInits == null) {
 462                                         return; // nothing to do, it was not yet set
 463                                 } else {
 464                                         // might need to grow the arrays
 465                                         if (vectorIndex >= extraDefiniteInits.length) {
 466                                                 return; // nothing to do, it was not yet set
 467                                         }
 468                                 }
 469                                 long mask;
 470                                 extraDefiniteInits[vectorIndex] &= ~(mask = 1L << (position % BitCacheSize));
 471                                 extraPotentialInits[vectorIndex] &= ~mask;
 472                         }
 473                 }
 474         }
 475
 476         /**
 477          * Clear the initialization info for a field
 478          */
 479         public void markAsDefinitelyNotAssigned(FieldBinding field) {
 480
 481                 if (this != DEAD_END)
 482                         markAsDefinitelyNotAssigned(field.id);
 483         }
 484
 485         /**
 486          * Clear the initialization info for a local variable
 487          */
 488
 489         public void markAsDefinitelyNotAssigned(LocalVariableBinding local) {
 490
 491                 if (this != DEAD_END)
 492                         markAsDefinitelyNotAssigned(local.id + maxFieldCount);
 493         }
 494
 495         /**
 496          * Returns the receiver updated in the following way:
 497          * <ul>
 498          * <li> intersection of definitely assigned variables,
 499          * <li> union of potentially assigned variables.
 500          * </ul>
 501          */
 502         public UnconditionalFlowInfo mergedWith(UnconditionalFlowInfo otherInits) {
 503
 504                 if (this == DEAD_END)
 505                         return otherInits;
 506                 if (otherInits == DEAD_END)
 507                         return this;
 508
 509                 if ((this.reachMode & UNREACHABLE) != (otherInits.reachMode & UNREACHABLE)) {
 510                         if ((this.reachMode & UNREACHABLE) != 0) {
 511                                 return otherInits;
 512                         } else {
 513                                 return this;
 514                         }
 515                 }
 516
 517                 // if one branch is not fake reachable, then the merged one is reachable
 518                 this.reachMode &= otherInits.reachMode;
 519
 520                 // intersection of definitely assigned variables,
 521                 this.definiteInits &= otherInits.definiteInits;
 522                 // union of potentially set ones
 523                 this.potentialInits |= otherInits.potentialInits;
 524
 525                 // treating extra storage
 526                 if (this.extraDefiniteInits != null) {
 527                         if (otherInits.extraDefiniteInits != null) {
 528                                 // both sides have extra storage
 529                                 int i = 0, length, otherLength;
 530                                 if ((length = this.extraDefiniteInits.length) < (otherLength = otherInits.extraDefiniteInits.length)) {
 531                                         // current storage is shorter -> grow current (could maybe
 532                                         // reuse otherInits extra storage?)
 533                                         System.arraycopy(this.extraDefiniteInits, 0,
 534                                                         (this.extraDefiniteInits = new long[otherLength]),
 535                                                         0, length);
 536                                         System.arraycopy(this.extraPotentialInits, 0,
 537                                                         (this.extraPotentialInits = new long[otherLength]),
 538                                                         0, length);
 539                                         while (i < length) {
 540                                                 this.extraDefiniteInits[i] &= otherInits.extraDefiniteInits[i];
 541                                                 this.extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
 542                                         }
 543                                         while (i < otherLength) {
 544                                                 this.extraPotentialInits[i] = otherInits.extraPotentialInits[i++];
 545                                         }
 546                                 } else {
 547                                         // current storage is longer
 548                                         while (i < otherLength) {
 549                                                 this.extraDefiniteInits[i] &= otherInits.extraDefiniteInits[i];
 550                                                 this.extraPotentialInits[i] |= otherInits.extraPotentialInits[i++];
 551                                         }
 552                                         while (i < length)
 553                                                 this.extraDefiniteInits[i++] = 0;
 554                                 }
 555                         } else {
 556                                 // no extra storage on otherInits
 557                                 int i = 0, length = this.extraDefiniteInits.length;
 558                                 while (i < length)
 559                                         this.extraDefiniteInits[i++] = 0;
 560                         }
 561                 } else if (otherInits.extraDefiniteInits != null) {
 562                         // no storage here, but other has extra storage.
 563                         int otherLength;
 564                         this.extraDefiniteInits = new long[otherLength = otherInits.extraDefiniteInits.length];
 565                         System.arraycopy(otherInits.extraPotentialInits, 0,
 566                                         (this.extraPotentialInits = new long[otherLength]), 0,
 567                                         otherLength);
 568                 }
 569                 return this;
 570         }
 571
 572         /*
 573          * Answer the total number of fields in enclosing types of a given type
 574          */
 575         static int numberOfEnclosingFields(ReferenceBinding type) {
 576
 577                 int count = 0;
 578                 type = type.enclosingType();
 579                 while (type != null) {
 580                         count += type.fieldCount();
 581                         type = type.enclosingType();
 582                 }
 583                 return count;
 584         }
 585
 586         public int reachMode() {
 587                 return this.reachMode;
 588         }
 589
 590         public FlowInfo setReachMode(int reachMode) {
 591
 592                 if (this == DEAD_END)
 593                         return this; // cannot modify DEAD_END
 594
 595                 // reset optional inits when becoming unreachable
 596                 if ((this.reachMode & UNREACHABLE) == 0
 597                                 && (reachMode & UNREACHABLE) != 0) {
 598                         this.potentialInits = 0;
 599                         if (this.extraPotentialInits != null) {
 600                                 for (int i = 0, length = this.extraPotentialInits.length; i < length; i++) {
 601                                         this.extraPotentialInits[i] = 0;
 602                                 }
 603                         }
 604                 }
 605                 this.reachMode = reachMode;
 606
 607                 return this;
 608         }
 609
 610         public String toString() {
 611
 612                 if (this == DEAD_END) {
 613                         return "FlowInfo.DEAD_END"; //$NON-NLS-1$
 614                 }
 615                 return "FlowInfo<def: " + this.definiteInits //$NON-NLS-1$
 616                                 + ", pot: " + this.potentialInits //$NON-NLS-1$
 617                                 + ", reachable:" + ((this.reachMode & UNREACHABLE) == 0) //$NON-NLS-1$
 618                                 + ">"; //$NON-NLS-1$
 619         }
 620
 621         public UnconditionalFlowInfo unconditionalInits() {
 622
 623                 // also see conditional inits, where it requests them to merge
 624                 return this;
 625         }
 626 }