runtime/Structure.cpp

   1 /*
   2  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "Structure.h"
  28
  29 #include "Identifier.h"
  30 #include "JSObject.h"
  31 #include "JSPropertyNameIterator.h"
  32 #include "Lookup.h"
  33 #include "PropertyNameArray.h"
  34 #include "StructureChain.h"
  35 #include <wtf/RefCountedLeakCounter.h>
  36 #include <wtf/RefPtr.h>
  37
  38 #if ENABLE(JSC_MULTIPLE_THREADS)
  39 #include <wtf/Threading.h>
  40 #endif
  41
  42 #define DUMP_STRUCTURE_ID_STATISTICS 0
  43
  44 #ifndef NDEBUG
  45 #define DO_PROPERTYMAP_CONSTENCY_CHECK 0
  46 #else
  47 #define DO_PROPERTYMAP_CONSTENCY_CHECK 0
  48 #endif
  49
  50 using namespace std;
  51 using namespace WTF;
  52
  53 namespace JSC {
  54
  55 // Choose a number for the following so that most property maps are smaller,
  56 // but it's not going to blow out the stack to allocate this number of pointers.
  57 static const int smallMapThreshold = 1024;
  58
  59 // The point at which the function call overhead of the qsort implementation
  60 // becomes small compared to the inefficiency of insertion sort.
  61 static const unsigned tinyMapThreshold = 20;
  62
  63 static const unsigned newTableSize = 16;
  64
  65 #ifndef NDEBUG
  66 static WTF::RefCountedLeakCounter structureCounter("Structure");
  67
  68 #if ENABLE(JSC_MULTIPLE_THREADS)
  69 static Mutex& ignoreSetMutex = *(new Mutex);
  70 #endif
  71
  72 static bool shouldIgnoreLeaks;
  73 static HashSet<Structure*>& ignoreSet = *(new HashSet<Structure*>);
  74 #endif
  75
  76 #if DUMP_STRUCTURE_ID_STATISTICS
  77 static HashSet<Structure*>& liveStructureSet = *(new HashSet<Structure*>);
  78 #endif
  79
  80 static int comparePropertyMapEntryIndices(const void* a, const void* b);
  81
  82 inline void Structure::setTransitionTable(TransitionTable* table)
  83 {
  84     ASSERT(m_isUsingSingleSlot);
  85 #ifndef NDEBUG
  86     setSingleTransition(0);
  87 #endif
  88     m_isUsingSingleSlot = false;
  89     m_transitions.m_table = table;
  90     // This implicitly clears the flag that indicates we're using a single transition
  91     ASSERT(!m_isUsingSingleSlot);
  92 }
  93
  94 // The contains and get methods accept imprecise matches, so if an unspecialised transition exists
  95 // for the given key they will consider that transition to be a match.  If a specialised transition
  96 // exists and it matches the provided specificValue, get will return the specific transition.
  97 inline bool Structure::transitionTableContains(const StructureTransitionTableHash::Key& key, JSCell* specificValue)
  98 {
  99     if (m_isUsingSingleSlot) {
 100         Structure* existingTransition = singleTransition();
 101         return existingTransition && existingTransition->m_nameInPrevious.get() == key.first
 102                && existingTransition->m_attributesInPrevious == key.second
 103                && (existingTransition->m_specificValueInPrevious == specificValue || existingTransition->m_specificValueInPrevious == 0);
 104     }
 105     TransitionTable::iterator find = transitionTable()->find(key);
 106     if (find == transitionTable()->end())
 107         return false;
 108
 109     return find->second.first || find->second.second->transitionedFor(specificValue);
 110 }
 111
 112 inline Structure* Structure::transitionTableGet(const StructureTransitionTableHash::Key& key, JSCell* specificValue) const
 113 {
 114     if (m_isUsingSingleSlot) {
 115         Structure* existingTransition = singleTransition();
 116         if (existingTransition && existingTransition->m_nameInPrevious.get() == key.first
 117             && existingTransition->m_attributesInPrevious == key.second
 118             && (existingTransition->m_specificValueInPrevious == specificValue || existingTransition->m_specificValueInPrevious == 0))
 119             return existingTransition;
 120         return 0;
 121     }
 122
 123     Transition transition = transitionTable()->get(key);
 124     if (transition.second && transition.second->transitionedFor(specificValue))
 125         return transition.second;
 126     return transition.first;
 127 }
 128
 129 inline bool Structure::transitionTableHasTransition(const StructureTransitionTableHash::Key& key) const
 130 {
 131     if (m_isUsingSingleSlot) {
 132         Structure* transition = singleTransition();
 133         return transition && transition->m_nameInPrevious == key.first
 134         && transition->m_attributesInPrevious == key.second;
 135     }
 136     return transitionTable()->contains(key);
 137 }
 138
 139 inline void Structure::transitionTableRemove(const StructureTransitionTableHash::Key& key, JSCell* specificValue)
 140 {
 141     if (m_isUsingSingleSlot) {
 142         ASSERT(transitionTableContains(key, specificValue));
 143         setSingleTransition(0);
 144         return;
 145     }
 146     TransitionTable::iterator find = transitionTable()->find(key);
 147     if (!specificValue)
 148         find->second.first = 0;
 149     else
 150         find->second.second = 0;
 151     if (!find->second.first && !find->second.second)
 152         transitionTable()->remove(find);
 153 }
 154
 155 inline void Structure::transitionTableAdd(const StructureTransitionTableHash::Key& key, Structure* structure, JSCell* specificValue)
 156 {
 157     if (m_isUsingSingleSlot) {
 158         if (!singleTransition()) {
 159             setSingleTransition(structure);
 160             return;
 161         }
 162         Structure* existingTransition = singleTransition();
 163         TransitionTable* transitionTable = new TransitionTable;
 164         setTransitionTable(transitionTable);
 165         if (existingTransition)
 166             transitionTableAdd(std::make_pair(existingTransition->m_nameInPrevious.get(), existingTransition->m_attributesInPrevious), existingTransition, existingTransition->m_specificValueInPrevious);
 167     }
 168     if (!specificValue) {
 169         TransitionTable::iterator find = transitionTable()->find(key);
 170         if (find == transitionTable()->end())
 171             transitionTable()->add(key, Transition(structure, static_cast<Structure*>(0)));
 172         else
 173             find->second.first = structure;
 174     } else {
 175         // If we're adding a transition to a specific value, then there cannot be
 176         // an existing transition
 177         ASSERT(!transitionTable()->contains(key));
 178         transitionTable()->add(key, Transition(static_cast<Structure*>(0), structure));
 179     }
 180 }
 181
 182 void Structure::dumpStatistics()
 183 {
 184 #if DUMP_STRUCTURE_ID_STATISTICS
 185     unsigned numberLeaf = 0;
 186     unsigned numberUsingSingleSlot = 0;
 187     unsigned numberSingletons = 0;
 188     unsigned numberWithPropertyMaps = 0;
 189     unsigned totalPropertyMapsSize = 0;
 190
 191     HashSet<Structure*>::const_iterator end = liveStructureSet.end();
 192     for (HashSet<Structure*>::const_iterator it = liveStructureSet.begin(); it != end; ++it) {
 193         Structure* structure = *it;
 194         if (structure->m_usingSingleTransitionSlot) {
 195             if (!structure->m_transitions.singleTransition)
 196                 ++numberLeaf;
 197             else
 198                 ++numberUsingSingleSlot;
 199
 200            if (!structure->m_previous && !structure->m_transitions.singleTransition)
 201                 ++numberSingletons;
 202         }
 203
 204         if (structure->m_propertyTable) {
 205             ++numberWithPropertyMaps;
 206             totalPropertyMapsSize += PropertyMapHashTable::allocationSize(structure->m_propertyTable->size);
 207             if (structure->m_propertyTable->deletedOffsets)
 208                 totalPropertyMapsSize += (structure->m_propertyTable->deletedOffsets->capacity() * sizeof(unsigned));
 209         }
 210     }
 211
 212     printf("Number of live Structures: %d\n", liveStructureSet.size());
 213     printf("Number of Structures using the single item optimization for transition map: %d\n", numberUsingSingleSlot);
 214     printf("Number of Structures that are leaf nodes: %d\n", numberLeaf);
 215     printf("Number of Structures that singletons: %d\n", numberSingletons);
 216     printf("Number of Structures with PropertyMaps: %d\n", numberWithPropertyMaps);
 217
 218     printf("Size of a single Structures: %d\n", static_cast<unsigned>(sizeof(Structure)));
 219     printf("Size of sum of all property maps: %d\n", totalPropertyMapsSize);
 220     printf("Size of average of all property maps: %f\n", static_cast<double>(totalPropertyMapsSize) / static_cast<double>(liveStructureSet.size()));
 221 #else
 222     printf("Dumping Structure statistics is not enabled.\n");
 223 #endif
 224 }
 225
 226 Structure::Structure(JSValue prototype, const TypeInfo& typeInfo, unsigned anonymousSlotCount)
 227     : m_typeInfo(typeInfo)
 228     , m_prototype(prototype)
 229     , m_specificValueInPrevious(0)
 230     , m_propertyTable(0)
 231     , m_propertyStorageCapacity(JSObject::inlineStorageCapacity)
 232     , m_offset(noOffset)
 233     , m_dictionaryKind(NoneDictionaryKind)
 234     , m_isPinnedPropertyTable(false)
 235     , m_hasGetterSetterProperties(false)
 236     , m_attributesInPrevious(0)
 237     , m_specificFunctionThrashCount(0)
 238     , m_anonymousSlotCount(anonymousSlotCount)
 239     , m_isUsingSingleSlot(true)
 240 {
 241     m_transitions.m_singleTransition = 0;
 242
 243     ASSERT(m_prototype);
 244     ASSERT(m_prototype.isObject() || m_prototype.isNull());
 245
 246 #ifndef NDEBUG
 247 #if ENABLE(JSC_MULTIPLE_THREADS)
 248     MutexLocker protect(ignoreSetMutex);
 249 #endif
 250     if (shouldIgnoreLeaks)
 251         ignoreSet.add(this);
 252     else
 253         structureCounter.increment();
 254 #endif
 255
 256 #if DUMP_STRUCTURE_ID_STATISTICS
 257     liveStructureSet.add(this);
 258 #endif
 259 }
 260
 261 Structure::~Structure()
 262 {
 263     if (m_previous) {
 264         ASSERT(m_nameInPrevious);
 265         m_previous->transitionTableRemove(make_pair(m_nameInPrevious.get(), m_attributesInPrevious), m_specificValueInPrevious);
 266
 267     }
 268     ASSERT(!m_enumerationCache.hasDeadObject());
 269
 270     if (m_propertyTable) {
 271         unsigned entryCount = m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount;
 272         for (unsigned i = 1; i <= entryCount; i++) {
 273             if (UString::Rep* key = m_propertyTable->entries()[i].key)
 274                 key->deref();
 275         }
 276
 277         delete m_propertyTable->deletedOffsets;
 278         fastFree(m_propertyTable);
 279     }
 280
 281     if (!m_isUsingSingleSlot)
 282         delete transitionTable();
 283
 284 #ifndef NDEBUG
 285 #if ENABLE(JSC_MULTIPLE_THREADS)
 286     MutexLocker protect(ignoreSetMutex);
 287 #endif
 288     HashSet<Structure*>::iterator it = ignoreSet.find(this);
 289     if (it != ignoreSet.end())
 290         ignoreSet.remove(it);
 291     else
 292         structureCounter.decrement();
 293 #endif
 294
 295 #if DUMP_STRUCTURE_ID_STATISTICS
 296     liveStructureSet.remove(this);
 297 #endif
 298 }
 299
 300 void Structure::startIgnoringLeaks()
 301 {
 302 #ifndef NDEBUG
 303     shouldIgnoreLeaks = true;
 304 #endif
 305 }
 306
 307 void Structure::stopIgnoringLeaks()
 308 {
 309 #ifndef NDEBUG
 310     shouldIgnoreLeaks = false;
 311 #endif
 312 }
 313
 314 static bool isPowerOf2(unsigned v)
 315 {
 316     // Taken from http://www.cs.utk.edu/~vose/c-stuff/bithacks.html
 317
 318     return !(v & (v - 1)) && v;
 319 }
 320
 321 static unsigned nextPowerOf2(unsigned v)
 322 {
 323     // Taken from http://www.cs.utk.edu/~vose/c-stuff/bithacks.html
 324     // Devised by Sean Anderson, Sepember 14, 2001
 325
 326     v--;
 327     v |= v >> 1;
 328     v |= v >> 2;
 329     v |= v >> 4;
 330     v |= v >> 8;
 331     v |= v >> 16;
 332     v++;
 333
 334     return v;
 335 }
 336
 337 static unsigned sizeForKeyCount(size_t keyCount)
 338 {
 339     if (keyCount == notFound)
 340         return newTableSize;
 341
 342     if (keyCount < 8)
 343         return newTableSize;
 344
 345     if (isPowerOf2(keyCount))
 346         return keyCount * 4;
 347
 348     return nextPowerOf2(keyCount) * 2;
 349 }
 350
 351 void Structure::materializePropertyMap()
 352 {
 353     ASSERT(!m_propertyTable);
 354
 355     Vector<Structure*, 8> structures;
 356     structures.append(this);
 357
 358     Structure* structure = this;
 359
 360     // Search for the last Structure with a property table.
 361     while ((structure = structure->previousID())) {
 362         if (structure->m_isPinnedPropertyTable) {
 363             ASSERT(structure->m_propertyTable);
 364             ASSERT(!structure->m_previous);
 365
 366             m_propertyTable = structure->copyPropertyTable();
 367             break;
 368         }
 369
 370         structures.append(structure);
 371     }
 372
 373     if (!m_propertyTable)
 374         createPropertyMapHashTable(sizeForKeyCount(m_offset + 1));
 375     else {
 376         if (sizeForKeyCount(m_offset + 1) > m_propertyTable->size)
 377             rehashPropertyMapHashTable(sizeForKeyCount(m_offset + 1)); // This could be made more efficient by combining with the copy above.
 378     }
 379
 380     for (ptrdiff_t i = structures.size() - 2; i >= 0; --i) {
 381         structure = structures[i];
 382         structure->m_nameInPrevious->ref();
 383         PropertyMapEntry entry(structure->m_nameInPrevious.get(), m_anonymousSlotCount + structure->m_offset, structure->m_attributesInPrevious, structure->m_specificValueInPrevious, ++m_propertyTable->lastIndexUsed);
 384         insertIntoPropertyMapHashTable(entry);
 385     }
 386 }
 387
 388 void Structure::growPropertyStorageCapacity()
 389 {
 390     if (m_propertyStorageCapacity == JSObject::inlineStorageCapacity)
 391         m_propertyStorageCapacity = JSObject::nonInlineBaseStorageCapacity;
 392     else
 393         m_propertyStorageCapacity *= 2;
 394 }
 395
 396 void Structure::despecifyDictionaryFunction(const Identifier& propertyName)
 397 {
 398     const UString::Rep* rep = propertyName._ustring.rep();
 399
 400     materializePropertyMapIfNecessary();
 401
 402     ASSERT(isDictionary());
 403     ASSERT(m_propertyTable);
 404
 405     unsigned i = rep->existingHash();
 406
 407 #if DUMP_PROPERTYMAP_STATS
 408     ++numProbes;
 409 #endif
 410
 411     unsigned entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
 412     ASSERT(entryIndex != emptyEntryIndex);
 413
 414     if (rep == m_propertyTable->entries()[entryIndex - 1].key) {
 415         m_propertyTable->entries()[entryIndex - 1].specificValue = 0;
 416         return;
 417     }
 418
 419 #if DUMP_PROPERTYMAP_STATS
 420     ++numCollisions;
 421 #endif
 422
 423     unsigned k = 1 | doubleHash(rep->existingHash());
 424
 425     while (1) {
 426         i += k;
 427
 428 #if DUMP_PROPERTYMAP_STATS
 429         ++numRehashes;
 430 #endif
 431
 432         entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
 433         ASSERT(entryIndex != emptyEntryIndex);
 434
 435         if (rep == m_propertyTable->entries()[entryIndex - 1].key) {
 436             m_propertyTable->entries()[entryIndex - 1].specificValue = 0;
 437             return;
 438         }
 439     }
 440 }
 441
 442 PassRefPtr<Structure> Structure::addPropertyTransitionToExistingStructure(Structure* structure, const Identifier& propertyName, unsigned attributes, JSCell* specificValue, size_t& offset)
 443 {
 444     ASSERT(!structure->isDictionary());
 445     ASSERT(structure->typeInfo().type() == ObjectType);
 446
 447     if (Structure* existingTransition = structure->transitionTableGet(make_pair(propertyName.ustring().rep(), attributes), specificValue)) {
 448         ASSERT(existingTransition->m_offset != noOffset);
 449         offset = existingTransition->m_offset + existingTransition->m_anonymousSlotCount;
 450         ASSERT(offset >= structure->m_anonymousSlotCount);
 451         ASSERT(structure->m_anonymousSlotCount == existingTransition->m_anonymousSlotCount);
 452         return existingTransition;
 453     }
 454
 455     return 0;
 456 }
 457
 458 PassRefPtr<Structure> Structure::addPropertyTransition(Structure* structure, const Identifier& propertyName, unsigned attributes, JSCell* specificValue, size_t& offset)
 459 {
 460     ASSERT(!structure->isDictionary());
 461     ASSERT(structure->typeInfo().type() == ObjectType);
 462     ASSERT(!Structure::addPropertyTransitionToExistingStructure(structure, propertyName, attributes, specificValue, offset));
 463
 464     if (structure->m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
 465         specificValue = 0;
 466
 467     if (structure->transitionCount() > s_maxTransitionLength) {
 468         RefPtr<Structure> transition = toCacheableDictionaryTransition(structure);
 469         ASSERT(structure != transition);
 470         offset = transition->put(propertyName, attributes, specificValue);
 471         ASSERT(offset >= structure->m_anonymousSlotCount);
 472         ASSERT(structure->m_anonymousSlotCount == transition->m_anonymousSlotCount);
 473         if (transition->propertyStorageSize() > transition->propertyStorageCapacity())
 474             transition->growPropertyStorageCapacity();
 475         return transition.release();
 476     }
 477
 478     RefPtr<Structure> transition = create(structure->m_prototype, structure->typeInfo(), structure->anonymousSlotCount());
 479
 480     transition->m_cachedPrototypeChain = structure->m_cachedPrototypeChain;
 481     transition->m_previous = structure;
 482     transition->m_nameInPrevious = propertyName.ustring().rep();
 483     transition->m_attributesInPrevious = attributes;
 484     transition->m_specificValueInPrevious = specificValue;
 485     transition->m_propertyStorageCapacity = structure->m_propertyStorageCapacity;
 486     transition->m_hasGetterSetterProperties = structure->m_hasGetterSetterProperties;
 487     transition->m_hasNonEnumerableProperties = structure->m_hasNonEnumerableProperties;
 488     transition->m_specificFunctionThrashCount = structure->m_specificFunctionThrashCount;
 489
 490     if (structure->m_propertyTable) {
 491         if (structure->m_isPinnedPropertyTable)
 492             transition->m_propertyTable = structure->copyPropertyTable();
 493         else {
 494             transition->m_propertyTable = structure->m_propertyTable;
 495             structure->m_propertyTable = 0;
 496         }
 497     } else {
 498         if (structure->m_previous)
 499             transition->materializePropertyMap();
 500         else
 501             transition->createPropertyMapHashTable();
 502     }
 503
 504     offset = transition->put(propertyName, attributes, specificValue);
 505     ASSERT(offset >= structure->m_anonymousSlotCount);
 506     ASSERT(structure->m_anonymousSlotCount == transition->m_anonymousSlotCount);
 507     if (transition->propertyStorageSize() > transition->propertyStorageCapacity())
 508         transition->growPropertyStorageCapacity();
 509
 510     transition->m_offset = offset - structure->m_anonymousSlotCount;
 511     ASSERT(structure->anonymousSlotCount() == transition->anonymousSlotCount());
 512     structure->transitionTableAdd(make_pair(propertyName.ustring().rep(), attributes), transition.get(), specificValue);
 513     return transition.release();
 514 }
 515
 516 PassRefPtr<Structure> Structure::removePropertyTransition(Structure* structure, const Identifier& propertyName, size_t& offset)
 517 {
 518     ASSERT(!structure->isUncacheableDictionary());
 519
 520     RefPtr<Structure> transition = toUncacheableDictionaryTransition(structure);
 521
 522     offset = transition->remove(propertyName);
 523     ASSERT(offset >= structure->m_anonymousSlotCount);
 524     ASSERT(structure->m_anonymousSlotCount == transition->m_anonymousSlotCount);
 525
 526     return transition.release();
 527 }
 528
 529 PassRefPtr<Structure> Structure::changePrototypeTransition(Structure* structure, JSValue prototype)
 530 {
 531     RefPtr<Structure> transition = create(prototype, structure->typeInfo(), structure->anonymousSlotCount());
 532
 533     transition->m_propertyStorageCapacity = structure->m_propertyStorageCapacity;
 534     transition->m_hasGetterSetterProperties = structure->m_hasGetterSetterProperties;
 535     transition->m_hasNonEnumerableProperties = structure->m_hasNonEnumerableProperties;
 536     transition->m_specificFunctionThrashCount = structure->m_specificFunctionThrashCount;
 537
 538     // Don't set m_offset, as one can not transition to this.
 539
 540     structure->materializePropertyMapIfNecessary();
 541     transition->m_propertyTable = structure->copyPropertyTable();
 542     transition->m_isPinnedPropertyTable = true;
 543
 544     ASSERT(structure->anonymousSlotCount() == transition->anonymousSlotCount());
 545     return transition.release();
 546 }
 547
 548 PassRefPtr<Structure> Structure::despecifyFunctionTransition(Structure* structure, const Identifier& replaceFunction)
 549 {
 550     ASSERT(structure->m_specificFunctionThrashCount < maxSpecificFunctionThrashCount);
 551     RefPtr<Structure> transition = create(structure->storedPrototype(), structure->typeInfo(), structure->anonymousSlotCount());
 552
 553     transition->m_propertyStorageCapacity = structure->m_propertyStorageCapacity;
 554     transition->m_hasGetterSetterProperties = structure->m_hasGetterSetterProperties;
 555     transition->m_hasNonEnumerableProperties = structure->m_hasNonEnumerableProperties;
 556     transition->m_specificFunctionThrashCount = structure->m_specificFunctionThrashCount + 1;
 557
 558     // Don't set m_offset, as one can not transition to this.
 559
 560     structure->materializePropertyMapIfNecessary();
 561     transition->m_propertyTable = structure->copyPropertyTable();
 562     transition->m_isPinnedPropertyTable = true;
 563
 564     if (transition->m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
 565         transition->despecifyAllFunctions();
 566     else {
 567         bool removed = transition->despecifyFunction(replaceFunction);
 568         ASSERT_UNUSED(removed, removed);
 569     }
 570
 571     ASSERT(structure->anonymousSlotCount() == transition->anonymousSlotCount());
 572     return transition.release();
 573 }
 574
 575 PassRefPtr<Structure> Structure::getterSetterTransition(Structure* structure)
 576 {
 577     RefPtr<Structure> transition = create(structure->storedPrototype(), structure->typeInfo(), structure->anonymousSlotCount());
 578     transition->m_propertyStorageCapacity = structure->m_propertyStorageCapacity;
 579     transition->m_hasGetterSetterProperties = transition->m_hasGetterSetterProperties;
 580     transition->m_hasNonEnumerableProperties = structure->m_hasNonEnumerableProperties;
 581     transition->m_specificFunctionThrashCount = structure->m_specificFunctionThrashCount;
 582
 583     // Don't set m_offset, as one can not transition to this.
 584
 585     structure->materializePropertyMapIfNecessary();
 586     transition->m_propertyTable = structure->copyPropertyTable();
 587     transition->m_isPinnedPropertyTable = true;
 588
 589     ASSERT(structure->anonymousSlotCount() == transition->anonymousSlotCount());
 590     return transition.release();
 591 }
 592
 593 PassRefPtr<Structure> Structure::toDictionaryTransition(Structure* structure, DictionaryKind kind)
 594 {
 595     ASSERT(!structure->isUncacheableDictionary());
 596
 597     RefPtr<Structure> transition = create(structure->m_prototype, structure->typeInfo(), structure->anonymousSlotCount());
 598     transition->m_dictionaryKind = kind;
 599     transition->m_propertyStorageCapacity = structure->m_propertyStorageCapacity;
 600     transition->m_hasGetterSetterProperties = structure->m_hasGetterSetterProperties;
 601     transition->m_hasNonEnumerableProperties = structure->m_hasNonEnumerableProperties;
 602     transition->m_specificFunctionThrashCount = structure->m_specificFunctionThrashCount;
 603
 604     structure->materializePropertyMapIfNecessary();
 605     transition->m_propertyTable = structure->copyPropertyTable();
 606     transition->m_isPinnedPropertyTable = true;
 607
 608     ASSERT(structure->anonymousSlotCount() == transition->anonymousSlotCount());
 609     return transition.release();
 610 }
 611
 612 PassRefPtr<Structure> Structure::toCacheableDictionaryTransition(Structure* structure)
 613 {
 614     return toDictionaryTransition(structure, CachedDictionaryKind);
 615 }
 616
 617 PassRefPtr<Structure> Structure::toUncacheableDictionaryTransition(Structure* structure)
 618 {
 619     return toDictionaryTransition(structure, UncachedDictionaryKind);
 620 }
 621
 622 PassRefPtr<Structure> Structure::flattenDictionaryStructure(JSObject* object)
 623 {
 624     ASSERT(isDictionary());
 625     if (isUncacheableDictionary()) {
 626         ASSERT(m_propertyTable);
 627         Vector<PropertyMapEntry*> sortedPropertyEntries(m_propertyTable->keyCount);
 628         PropertyMapEntry** p = sortedPropertyEntries.data();
 629         unsigned entryCount = m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount;
 630         for (unsigned i = 1; i <= entryCount; i++) {
 631             if (m_propertyTable->entries()[i].key)
 632                 *p++ = &m_propertyTable->entries()[i];
 633         }
 634         size_t propertyCount = p - sortedPropertyEntries.data();
 635         qsort(sortedPropertyEntries.data(), propertyCount, sizeof(PropertyMapEntry*), comparePropertyMapEntryIndices);
 636         sortedPropertyEntries.resize(propertyCount);
 637
 638         // We now have the properties currently defined on this object
 639         // in the order that they are expected to be in, but we need to
 640         // reorder the storage, so we have to copy the current values out
 641         Vector<JSValue> values(propertyCount);
 642         unsigned anonymousSlotCount = m_anonymousSlotCount;
 643         for (unsigned i = 0; i < propertyCount; i++) {
 644             PropertyMapEntry* entry = sortedPropertyEntries[i];
 645             values[i] = object->getDirectOffset(entry->offset);
 646             // Update property table to have the new property offsets
 647             entry->offset = anonymousSlotCount + i;
 648             entry->index = i;
 649         }
 650
 651         // Copy the original property values into their final locations
 652         for (unsigned i = 0; i < propertyCount; i++)
 653             object->putDirectOffset(anonymousSlotCount + i, values[i]);
 654
 655         if (m_propertyTable->deletedOffsets) {
 656             delete m_propertyTable->deletedOffsets;
 657             m_propertyTable->deletedOffsets = 0;
 658         }
 659     }
 660
 661     m_dictionaryKind = NoneDictionaryKind;
 662     return this;
 663 }
 664
 665 size_t Structure::addPropertyWithoutTransition(const Identifier& propertyName, unsigned attributes, JSCell* specificValue)
 666 {
 667     ASSERT(!m_enumerationCache);
 668
 669     if (m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
 670         specificValue = 0;
 671
 672     materializePropertyMapIfNecessary();
 673
 674     m_isPinnedPropertyTable = true;
 675
 676     size_t offset = put(propertyName, attributes, specificValue);
 677     ASSERT(offset >= m_anonymousSlotCount);
 678     if (propertyStorageSize() > propertyStorageCapacity())
 679         growPropertyStorageCapacity();
 680     return offset;
 681 }
 682
 683 size_t Structure::removePropertyWithoutTransition(const Identifier& propertyName)
 684 {
 685     ASSERT(isUncacheableDictionary());
 686     ASSERT(!m_enumerationCache);
 687
 688     materializePropertyMapIfNecessary();
 689
 690     m_isPinnedPropertyTable = true;
 691     size_t offset = remove(propertyName);
 692     ASSERT(offset >= m_anonymousSlotCount);
 693     return offset;
 694 }
 695
 696 #if DUMP_PROPERTYMAP_STATS
 697
 698 static int numProbes;
 699 static int numCollisions;
 700 static int numRehashes;
 701 static int numRemoves;
 702
 703 struct PropertyMapStatisticsExitLogger {
 704     ~PropertyMapStatisticsExitLogger();
 705 };
 706
 707 static PropertyMapStatisticsExitLogger logger;
 708
 709 PropertyMapStatisticsExitLogger::~PropertyMapStatisticsExitLogger()
 710 {
 711     printf("\nJSC::PropertyMap statistics\n\n");
 712     printf("%d probes\n", numProbes);
 713     printf("%d collisions (%.1f%%)\n", numCollisions, 100.0 * numCollisions / numProbes);
 714     printf("%d rehashes\n", numRehashes);
 715     printf("%d removes\n", numRemoves);
 716 }
 717
 718 #endif
 719
 720 static const unsigned deletedSentinelIndex = 1;
 721
 722 #if !DO_PROPERTYMAP_CONSTENCY_CHECK
 723
 724 inline void Structure::checkConsistency()
 725 {
 726 }
 727
 728 #endif
 729
 730 PropertyMapHashTable* Structure::copyPropertyTable()
 731 {
 732     if (!m_propertyTable)
 733         return 0;
 734
 735     size_t tableSize = PropertyMapHashTable::allocationSize(m_propertyTable->size);
 736     PropertyMapHashTable* newTable = static_cast<PropertyMapHashTable*>(fastMalloc(tableSize));
 737     memcpy(newTable, m_propertyTable, tableSize);
 738
 739     unsigned entryCount = m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount;
 740     for (unsigned i = 1; i <= entryCount; ++i) {
 741         if (UString::Rep* key = newTable->entries()[i].key)
 742             key->ref();
 743     }
 744
 745     // Copy the deletedOffsets vector.
 746     if (m_propertyTable->deletedOffsets)
 747         newTable->deletedOffsets = new Vector<unsigned>(*m_propertyTable->deletedOffsets);
 748
 749     return newTable;
 750 }
 751
 752 size_t Structure::get(const UString::Rep* rep, unsigned& attributes, JSCell*& specificValue)
 753 {
 754     materializePropertyMapIfNecessary();
 755     if (!m_propertyTable)
 756         return notFound;
 757
 758     unsigned i = rep->existingHash();
 759
 760 #if DUMP_PROPERTYMAP_STATS
 761     ++numProbes;
 762 #endif
 763
 764     unsigned entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
 765     if (entryIndex == emptyEntryIndex)
 766         return notFound;
 767
 768     if (rep == m_propertyTable->entries()[entryIndex - 1].key) {
 769         attributes = m_propertyTable->entries()[entryIndex - 1].attributes;
 770         specificValue = m_propertyTable->entries()[entryIndex - 1].specificValue;
 771         ASSERT(m_propertyTable->entries()[entryIndex - 1].offset >= m_anonymousSlotCount);
 772         return m_propertyTable->entries()[entryIndex - 1].offset;
 773     }
 774
 775 #if DUMP_PROPERTYMAP_STATS
 776     ++numCollisions;
 777 #endif
 778
 779     unsigned k = 1 | doubleHash(rep->existingHash());
 780
 781     while (1) {
 782         i += k;
 783
 784 #if DUMP_PROPERTYMAP_STATS
 785         ++numRehashes;
 786 #endif
 787
 788         entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
 789         if (entryIndex == emptyEntryIndex)
 790             return notFound;
 791
 792         if (rep == m_propertyTable->entries()[entryIndex - 1].key) {
 793             attributes = m_propertyTable->entries()[entryIndex - 1].attributes;
 794             specificValue = m_propertyTable->entries()[entryIndex - 1].specificValue;
 795             ASSERT(m_propertyTable->entries()[entryIndex - 1].offset >= m_anonymousSlotCount);
 796             return m_propertyTable->entries()[entryIndex - 1].offset;
 797         }
 798     }
 799 }
 800
 801 bool Structure::despecifyFunction(const Identifier& propertyName)
 802 {
 803     ASSERT(!propertyName.isNull());
 804
 805     materializePropertyMapIfNecessary();
 806     if (!m_propertyTable)
 807         return false;
 808
 809     UString::Rep* rep = propertyName._ustring.rep();
 810
 811     unsigned i = rep->existingHash();
 812
 813 #if DUMP_PROPERTYMAP_STATS
 814     ++numProbes;
 815 #endif
 816
 817     unsigned entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
 818     if (entryIndex == emptyEntryIndex)
 819         return false;
 820
 821     if (rep == m_propertyTable->entries()[entryIndex - 1].key) {
 822         ASSERT(m_propertyTable->entries()[entryIndex - 1].specificValue);
 823         m_propertyTable->entries()[entryIndex - 1].specificValue = 0;
 824         return true;
 825     }
 826
 827 #if DUMP_PROPERTYMAP_STATS
 828     ++numCollisions;
 829 #endif
 830
 831     unsigned k = 1 | doubleHash(rep->existingHash());
 832
 833     while (1) {
 834         i += k;
 835
 836 #if DUMP_PROPERTYMAP_STATS
 837         ++numRehashes;
 838 #endif
 839
 840         entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
 841         if (entryIndex == emptyEntryIndex)
 842             return false;
 843
 844         if (rep == m_propertyTable->entries()[entryIndex - 1].key) {
 845             ASSERT(m_propertyTable->entries()[entryIndex - 1].specificValue);
 846             m_propertyTable->entries()[entryIndex - 1].specificValue = 0;
 847             return true;
 848         }
 849     }
 850 }
 851
 852 void Structure::despecifyAllFunctions()
 853 {
 854     materializePropertyMapIfNecessary();
 855     if (!m_propertyTable)
 856         return;
 857
 858     unsigned entryCount = m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount;
 859     for (unsigned i = 1; i <= entryCount; ++i)
 860         m_propertyTable->entries()[i].specificValue = 0;
 861 }
 862
 863 size_t Structure::put(const Identifier& propertyName, unsigned attributes, JSCell* specificValue)
 864 {
 865     ASSERT(!propertyName.isNull());
 866     ASSERT(get(propertyName) == notFound);
 867
 868     checkConsistency();
 869
 870     if (attributes & DontEnum)
 871         m_hasNonEnumerableProperties = true;
 872
 873     UString::Rep* rep = propertyName._ustring.rep();
 874
 875     if (!m_propertyTable)
 876         createPropertyMapHashTable();
 877
 878     // FIXME: Consider a fast case for tables with no deleted sentinels.
 879
 880     unsigned i = rep->existingHash();
 881     unsigned k = 0;
 882     bool foundDeletedElement = false;
 883     unsigned deletedElementIndex = 0; // initialize to make the compiler happy
 884
 885 #if DUMP_PROPERTYMAP_STATS
 886     ++numProbes;
 887 #endif
 888
 889     while (1) {
 890         unsigned entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
 891         if (entryIndex == emptyEntryIndex)
 892             break;
 893
 894         if (entryIndex == deletedSentinelIndex) {
 895             // If we find a deleted-element sentinel, remember it for use later.
 896             if (!foundDeletedElement) {
 897                 foundDeletedElement = true;
 898                 deletedElementIndex = i;
 899             }
 900         }
 901
 902         if (k == 0) {
 903             k = 1 | doubleHash(rep->existingHash());
 904 #if DUMP_PROPERTYMAP_STATS
 905             ++numCollisions;
 906 #endif
 907         }
 908
 909         i += k;
 910
 911 #if DUMP_PROPERTYMAP_STATS
 912         ++numRehashes;
 913 #endif
 914     }
 915
 916     // Figure out which entry to use.
 917     unsigned entryIndex = m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount + 2;
 918     if (foundDeletedElement) {
 919         i = deletedElementIndex;
 920         --m_propertyTable->deletedSentinelCount;
 921
 922         // Since we're not making the table bigger, we can't use the entry one past
 923         // the end that we were planning on using, so search backwards for the empty
 924         // slot that we can use. We know it will be there because we did at least one
 925         // deletion in the past that left an entry empty.
 926         while (m_propertyTable->entries()[--entryIndex - 1].key) { }
 927     }
 928
 929     // Create a new hash table entry.
 930     m_propertyTable->entryIndices[i & m_propertyTable->sizeMask] = entryIndex;
 931
 932     // Create a new hash table entry.
 933     rep->ref();
 934     m_propertyTable->entries()[entryIndex - 1].key = rep;
 935     m_propertyTable->entries()[entryIndex - 1].attributes = attributes;
 936     m_propertyTable->entries()[entryIndex - 1].specificValue = specificValue;
 937     m_propertyTable->entries()[entryIndex - 1].index = ++m_propertyTable->lastIndexUsed;
 938
 939     unsigned newOffset;
 940     if (m_propertyTable->deletedOffsets && !m_propertyTable->deletedOffsets->isEmpty()) {
 941         newOffset = m_propertyTable->deletedOffsets->last();
 942         m_propertyTable->deletedOffsets->removeLast();
 943     } else
 944         newOffset = m_propertyTable->keyCount + m_anonymousSlotCount;
 945     m_propertyTable->entries()[entryIndex - 1].offset = newOffset;
 946
 947     ASSERT(newOffset >= m_anonymousSlotCount);
 948     ++m_propertyTable->keyCount;
 949
 950     if ((m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount) * 2 >= m_propertyTable->size)
 951         expandPropertyMapHashTable();
 952
 953     checkConsistency();
 954     return newOffset;
 955 }
 956
 957 bool Structure::hasTransition(UString::Rep* rep, unsigned attributes)
 958 {
 959     return transitionTableHasTransition(make_pair(rep, attributes));
 960 }
 961
 962 size_t Structure::remove(const Identifier& propertyName)
 963 {
 964     ASSERT(!propertyName.isNull());
 965
 966     checkConsistency();
 967
 968     UString::Rep* rep = propertyName._ustring.rep();
 969
 970     if (!m_propertyTable)
 971         return notFound;
 972
 973 #if DUMP_PROPERTYMAP_STATS
 974     ++numProbes;
 975     ++numRemoves;
 976 #endif
 977
 978     // Find the thing to remove.
 979     unsigned i = rep->existingHash();
 980     unsigned k = 0;
 981     unsigned entryIndex;
 982     UString::Rep* key = 0;
 983     while (1) {
 984         entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
 985         if (entryIndex == emptyEntryIndex)
 986             return notFound;
 987
 988         key = m_propertyTable->entries()[entryIndex - 1].key;
 989         if (rep == key)
 990             break;
 991
 992         if (k == 0) {
 993             k = 1 | doubleHash(rep->existingHash());
 994 #if DUMP_PROPERTYMAP_STATS
 995             ++numCollisions;
 996 #endif
 997         }
 998
 999         i += k;
1000
1001 #if DUMP_PROPERTYMAP_STATS
1002         ++numRehashes;
1003 #endif
1004     }
1005
1006     // Replace this one element with the deleted sentinel. Also clear out
1007     // the entry so we can iterate all the entries as needed.
1008     m_propertyTable->entryIndices[i & m_propertyTable->sizeMask] = deletedSentinelIndex;
1009
1010     size_t offset = m_propertyTable->entries()[entryIndex - 1].offset;
1011     ASSERT(offset >= m_anonymousSlotCount);
1012
1013     key->deref();
1014     m_propertyTable->entries()[entryIndex - 1].key = 0;
1015     m_propertyTable->entries()[entryIndex - 1].attributes = 0;
1016     m_propertyTable->entries()[entryIndex - 1].specificValue = 0;
1017     m_propertyTable->entries()[entryIndex - 1].offset = 0;
1018
1019     if (!m_propertyTable->deletedOffsets)
1020         m_propertyTable->deletedOffsets = new Vector<unsigned>;
1021     m_propertyTable->deletedOffsets->append(offset);
1022
1023     ASSERT(m_propertyTable->keyCount >= 1);
1024     --m_propertyTable->keyCount;
1025     ++m_propertyTable->deletedSentinelCount;
1026
1027     if (m_propertyTable->deletedSentinelCount * 4 >= m_propertyTable->size)
1028         rehashPropertyMapHashTable();
1029
1030     checkConsistency();
1031     return offset;
1032 }
1033
1034 void Structure::insertIntoPropertyMapHashTable(const PropertyMapEntry& entry)
1035 {
1036     ASSERT(m_propertyTable);
1037     ASSERT(entry.offset >= m_anonymousSlotCount);
1038     unsigned i = entry.key->existingHash();
1039     unsigned k = 0;
1040
1041 #if DUMP_PROPERTYMAP_STATS
1042     ++numProbes;
1043 #endif
1044
1045     while (1) {
1046         unsigned entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
1047         if (entryIndex == emptyEntryIndex)
1048             break;
1049
1050         if (k == 0) {
1051             k = 1 | doubleHash(entry.key->existingHash());
1052 #if DUMP_PROPERTYMAP_STATS
1053             ++numCollisions;
1054 #endif
1055         }
1056
1057         i += k;
1058
1059 #if DUMP_PROPERTYMAP_STATS
1060         ++numRehashes;
1061 #endif
1062     }
1063
1064     unsigned entryIndex = m_propertyTable->keyCount + 2;
1065     m_propertyTable->entryIndices[i & m_propertyTable->sizeMask] = entryIndex;
1066     m_propertyTable->entries()[entryIndex - 1] = entry;
1067
1068     ++m_propertyTable->keyCount;
1069 }
1070
1071 void Structure::createPropertyMapHashTable()
1072 {
1073     ASSERT(sizeForKeyCount(7) == newTableSize);
1074     createPropertyMapHashTable(newTableSize);
1075 }
1076
1077 void Structure::createPropertyMapHashTable(unsigned newTableSize)
1078 {
1079     ASSERT(!m_propertyTable);
1080     ASSERT(isPowerOf2(newTableSize));
1081
1082     checkConsistency();
1083
1084     m_propertyTable = static_cast<PropertyMapHashTable*>(fastZeroedMalloc(PropertyMapHashTable::allocationSize(newTableSize)));
1085     m_propertyTable->size = newTableSize;
1086     m_propertyTable->sizeMask = newTableSize - 1;
1087
1088     checkConsistency();
1089 }
1090
1091 void Structure::expandPropertyMapHashTable()
1092 {
1093     ASSERT(m_propertyTable);
1094     rehashPropertyMapHashTable(m_propertyTable->size * 2);
1095 }
1096
1097 void Structure::rehashPropertyMapHashTable()
1098 {
1099     ASSERT(m_propertyTable);
1100     ASSERT(m_propertyTable->size);
1101     rehashPropertyMapHashTable(m_propertyTable->size);
1102 }
1103
1104 void Structure::rehashPropertyMapHashTable(unsigned newTableSize)
1105 {
1106     ASSERT(m_propertyTable);
1107     ASSERT(isPowerOf2(newTableSize));
1108
1109     checkConsistency();
1110
1111     PropertyMapHashTable* oldTable = m_propertyTable;
1112
1113     m_propertyTable = static_cast<PropertyMapHashTable*>(fastZeroedMalloc(PropertyMapHashTable::allocationSize(newTableSize)));
1114     m_propertyTable->size = newTableSize;
1115     m_propertyTable->sizeMask = newTableSize - 1;
1116
1117     unsigned lastIndexUsed = 0;
1118     unsigned entryCount = oldTable->keyCount + oldTable->deletedSentinelCount;
1119     for (unsigned i = 1; i <= entryCount; ++i) {
1120         if (oldTable->entries()[i].key) {
1121             lastIndexUsed = max(oldTable->entries()[i].index, lastIndexUsed);
1122             insertIntoPropertyMapHashTable(oldTable->entries()[i]);
1123         }
1124     }
1125     m_propertyTable->lastIndexUsed = lastIndexUsed;
1126     m_propertyTable->deletedOffsets = oldTable->deletedOffsets;
1127
1128     fastFree(oldTable);
1129
1130     checkConsistency();
1131 }
1132
1133 int comparePropertyMapEntryIndices(const void* a, const void* b)
1134 {
1135     unsigned ia = static_cast<PropertyMapEntry* const*>(a)[0]->index;
1136     unsigned ib = static_cast<PropertyMapEntry* const*>(b)[0]->index;
1137     if (ia < ib)
1138         return -1;
1139     if (ia > ib)
1140         return +1;
1141     return 0;
1142 }
1143
1144 void Structure::getPropertyNames(PropertyNameArray& propertyNames, EnumerationMode mode)
1145 {
1146     materializePropertyMapIfNecessary();
1147     if (!m_propertyTable)
1148         return;
1149
1150     if (m_propertyTable->keyCount < tinyMapThreshold) {
1151         PropertyMapEntry* a[tinyMapThreshold];
1152         int i = 0;
1153         unsigned entryCount = m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount;
1154         for (unsigned k = 1; k <= entryCount; k++) {
1155             ASSERT(m_hasNonEnumerableProperties || !(m_propertyTable->entries()[k].attributes & DontEnum));
1156             if (m_propertyTable->entries()[k].key && (!(m_propertyTable->entries()[k].attributes & DontEnum) || (mode == IncludeDontEnumProperties))) {
1157                 PropertyMapEntry* value = &m_propertyTable->entries()[k];
1158                 int j;
1159                 for (j = i - 1; j >= 0 && a[j]->index > value->index; --j)
1160                     a[j + 1] = a[j];
1161                 a[j + 1] = value;
1162                 ++i;
1163             }
1164         }
1165         if (!propertyNames.size()) {
1166             for (int k = 0; k < i; ++k)
1167                 propertyNames.addKnownUnique(a[k]->key);
1168         } else {
1169             for (int k = 0; k < i; ++k)
1170                 propertyNames.add(a[k]->key);
1171         }
1172
1173         return;
1174     }
1175
1176     // Allocate a buffer to use to sort the keys.
1177     Vector<PropertyMapEntry*, smallMapThreshold> sortedEnumerables(m_propertyTable->keyCount);
1178
1179     // Get pointers to the enumerable entries in the buffer.
1180     PropertyMapEntry** p = sortedEnumerables.data();
1181     unsigned entryCount = m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount;
1182     for (unsigned i = 1; i <= entryCount; i++) {
1183         if (m_propertyTable->entries()[i].key && (!(m_propertyTable->entries()[i].attributes & DontEnum) || (mode == IncludeDontEnumProperties)))
1184             *p++ = &m_propertyTable->entries()[i];
1185     }
1186
1187     size_t enumerableCount = p - sortedEnumerables.data();
1188     // Sort the entries by index.
1189     qsort(sortedEnumerables.data(), enumerableCount, sizeof(PropertyMapEntry*), comparePropertyMapEntryIndices);
1190     sortedEnumerables.resize(enumerableCount);
1191
1192     // Put the keys of the sorted entries into the list.
1193     if (!propertyNames.size()) {
1194         for (size_t i = 0; i < sortedEnumerables.size(); ++i)
1195             propertyNames.addKnownUnique(sortedEnumerables[i]->key);
1196     } else {
1197         for (size_t i = 0; i < sortedEnumerables.size(); ++i)
1198             propertyNames.add(sortedEnumerables[i]->key);
1199     }
1200 }
1201
1202 #if DO_PROPERTYMAP_CONSTENCY_CHECK
1203
1204 void Structure::checkConsistency()
1205 {
1206     if (!m_propertyTable)
1207         return;
1208
1209     ASSERT(m_propertyTable->size >= newTableSize);
1210     ASSERT(m_propertyTable->sizeMask);
1211     ASSERT(m_propertyTable->size == m_propertyTable->sizeMask + 1);
1212     ASSERT(!(m_propertyTable->size & m_propertyTable->sizeMask));
1213
1214     ASSERT(m_propertyTable->keyCount <= m_propertyTable->size / 2);
1215     ASSERT(m_propertyTable->deletedSentinelCount <= m_propertyTable->size / 4);
1216
1217     ASSERT(m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount <= m_propertyTable->size / 2);
1218
1219     unsigned indexCount = 0;
1220     unsigned deletedIndexCount = 0;
1221     for (unsigned a = 0; a != m_propertyTable->size; ++a) {
1222         unsigned entryIndex = m_propertyTable->entryIndices[a];
1223         if (entryIndex == emptyEntryIndex)
1224             continue;
1225         if (entryIndex == deletedSentinelIndex) {
1226             ++deletedIndexCount;
1227             continue;
1228         }
1229         ASSERT(entryIndex > deletedSentinelIndex);
1230         ASSERT(entryIndex - 1 <= m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount);
1231         ++indexCount;
1232
1233         for (unsigned b = a + 1; b != m_propertyTable->size; ++b)
1234             ASSERT(m_propertyTable->entryIndices[b] != entryIndex);
1235     }
1236     ASSERT(indexCount == m_propertyTable->keyCount);
1237     ASSERT(deletedIndexCount == m_propertyTable->deletedSentinelCount);
1238
1239     ASSERT(m_propertyTable->entries()[0].key == 0);
1240
1241     unsigned nonEmptyEntryCount = 0;
1242     for (unsigned c = 1; c <= m_propertyTable->keyCount + m_propertyTable->deletedSentinelCount; ++c) {
1243         ASSERT(m_hasNonEnumerableProperties || !(m_propertyTable->entries()[c].attributes & DontEnum));
1244         UString::Rep* rep = m_propertyTable->entries()[c].key;
1245         ASSERT(m_propertyTable->entries()[c].offset >= m_anonymousSlotCount);
1246         if (!rep)
1247             continue;
1248         ++nonEmptyEntryCount;
1249         unsigned i = rep->existingHash();
1250         unsigned k = 0;
1251         unsigned entryIndex;
1252         while (1) {
1253             entryIndex = m_propertyTable->entryIndices[i & m_propertyTable->sizeMask];
1254             ASSERT(entryIndex != emptyEntryIndex);
1255             if (rep == m_propertyTable->entries()[entryIndex - 1].key)
1256                 break;
1257             if (k == 0)
1258                 k = 1 | doubleHash(rep->existingHash());
1259             i += k;
1260         }
1261         ASSERT(entryIndex == c + 1);
1262     }
1263
1264     ASSERT(nonEmptyEntryCount == m_propertyTable->keyCount);
1265 }
1266
1267 #endif // DO_PROPERTYMAP_CONSTENCY_CHECK
1268
1269 } // namespace JSC