runtime/Structure.cpp

   1 /*
   2  * Copyright (C) 2008, 2009, 2013 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 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 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 "CodeBlock.h"
  30 #include "DumpContext.h"
  31 #include "JSCInlines.h"
  32 #include "JSObject.h"
  33 #include "JSPropertyNameIterator.h"
  34 #include "Lookup.h"
  35 #include "PropertyMapHashTable.h"
  36 #include "PropertyNameArray.h"
  37 #include "StructureChain.h"
  38 #include "StructureRareDataInlines.h"
  39 #include <wtf/CommaPrinter.h>
  40 #include <wtf/ProcessID.h>
  41 #include <wtf/RefCountedLeakCounter.h>
  42 #include <wtf/RefPtr.h>
  43 #include <wtf/Threading.h>
  44
  45 #define DUMP_STRUCTURE_ID_STATISTICS 0
  46
  47 #ifndef NDEBUG
  48 #define DO_PROPERTYMAP_CONSTENCY_CHECK 0
  49 #else
  50 #define DO_PROPERTYMAP_CONSTENCY_CHECK 0
  51 #endif
  52
  53 using namespace std;
  54 using namespace WTF;
  55
  56 namespace JSC {
  57
  58 #if DUMP_STRUCTURE_ID_STATISTICS
  59 static HashSet<Structure*>& liveStructureSet = *(new HashSet<Structure*>);
  60 #endif
  61
  62 bool StructureTransitionTable::contains(StringImpl* rep, unsigned attributes) const
  63 {
  64     if (isUsingSingleSlot()) {
  65         Structure* transition = singleTransition();
  66         return transition && transition->m_nameInPrevious == rep && transition->m_attributesInPrevious == attributes;
  67     }
  68     return map()->get(std::make_pair(rep, attributes));
  69 }
  70
  71 inline Structure* StructureTransitionTable::get(StringImpl* rep, unsigned attributes) const
  72 {
  73     if (isUsingSingleSlot()) {
  74         Structure* transition = singleTransition();
  75         return (transition && transition->m_nameInPrevious == rep && transition->m_attributesInPrevious == attributes) ? transition : 0;
  76     }
  77     return map()->get(std::make_pair(rep, attributes));
  78 }
  79
  80 inline void StructureTransitionTable::add(VM& vm, Structure* structure)
  81 {
  82     if (isUsingSingleSlot()) {
  83         Structure* existingTransition = singleTransition();
  84
  85         // This handles the first transition being added.
  86         if (!existingTransition) {
  87             setSingleTransition(vm, structure);
  88             return;
  89         }
  90
  91         // This handles the second transition being added
  92         // (or the first transition being despecified!)
  93         setMap(new TransitionMap());
  94         add(vm, existingTransition);
  95     }
  96
  97     // Add the structure to the map.
  98
  99     // Newer versions of the STL have an std::make_pair function that takes rvalue references.
 100     // When either of the parameters are bitfields, the C++ compiler will try to bind them as lvalues, which is invalid. To work around this, use unary "+" to make the parameter an rvalue.
 101     // See https://bugs.webkit.org/show_bug.cgi?id=59261 for more details
 102     map()->set(std::make_pair(structure->m_nameInPrevious.get(), +structure->m_attributesInPrevious), structure);
 103 }
 104
 105 void Structure::dumpStatistics()
 106 {
 107 #if DUMP_STRUCTURE_ID_STATISTICS
 108     unsigned numberLeaf = 0;
 109     unsigned numberUsingSingleSlot = 0;
 110     unsigned numberSingletons = 0;
 111     unsigned numberWithPropertyMaps = 0;
 112     unsigned totalPropertyMapsSize = 0;
 113
 114     HashSet<Structure*>::const_iterator end = liveStructureSet.end();
 115     for (HashSet<Structure*>::const_iterator it = liveStructureSet.begin(); it != end; ++it) {
 116         Structure* structure = *it;
 117
 118         switch (structure->m_transitionTable.size()) {
 119             case 0:
 120                 ++numberLeaf;
 121                 if (!structure->previousID())
 122                     ++numberSingletons;
 123                 break;
 124
 125             case 1:
 126                 ++numberUsingSingleSlot;
 127                 break;
 128         }
 129
 130         if (structure->propertyTable()) {
 131             ++numberWithPropertyMaps;
 132             totalPropertyMapsSize += structure->propertyTable()->sizeInMemory();
 133         }
 134     }
 135
 136     dataLogF("Number of live Structures: %d\n", liveStructureSet.size());
 137     dataLogF("Number of Structures using the single item optimization for transition map: %d\n", numberUsingSingleSlot);
 138     dataLogF("Number of Structures that are leaf nodes: %d\n", numberLeaf);
 139     dataLogF("Number of Structures that singletons: %d\n", numberSingletons);
 140     dataLogF("Number of Structures with PropertyMaps: %d\n", numberWithPropertyMaps);
 141
 142     dataLogF("Size of a single Structures: %d\n", static_cast<unsigned>(sizeof(Structure)));
 143     dataLogF("Size of sum of all property maps: %d\n", totalPropertyMapsSize);
 144     dataLogF("Size of average of all property maps: %f\n", static_cast<double>(totalPropertyMapsSize) / static_cast<double>(liveStructureSet.size()));
 145 #else
 146     dataLogF("Dumping Structure statistics is not enabled.\n");
 147 #endif
 148 }
 149
 150 Structure::Structure(VM& vm, JSGlobalObject* globalObject, JSValue prototype, const TypeInfo& typeInfo, const ClassInfo* classInfo, IndexingType indexingType, unsigned inlineCapacity)
 151     : JSCell(vm, vm.structureStructure.get())
 152     , m_blob(vm.heap.structureIDTable().allocateID(this), indexingType, typeInfo)
 153     , m_outOfLineTypeFlags(typeInfo.outOfLineTypeFlags())
 154     , m_globalObject(vm, this, globalObject, WriteBarrier<JSGlobalObject>::MayBeNull)
 155     , m_prototype(vm, this, prototype)
 156     , m_classInfo(classInfo)
 157     , m_transitionWatchpointSet(IsWatched)
 158     , m_offset(invalidOffset)
 159     , m_inlineCapacity(inlineCapacity)
 160     , m_dictionaryKind(NoneDictionaryKind)
 161     , m_hasBeenFlattenedBefore(false)
 162     , m_isPinnedPropertyTable(false)
 163     , m_hasGetterSetterProperties(classInfo->hasStaticSetterOrReadonlyProperties(vm))
 164     , m_hasCustomGetterSetterProperties(false)
 165     , m_hasReadOnlyOrGetterSetterPropertiesExcludingProto(classInfo->hasStaticSetterOrReadonlyProperties(vm))
 166     , m_hasNonEnumerableProperties(false)
 167     , m_attributesInPrevious(0)
 168     , m_specificFunctionThrashCount(0)
 169     , m_preventExtensions(false)
 170     , m_didTransition(false)
 171     , m_staticFunctionReified(false)
 172     , m_hasRareData(false)
 173 {
 174     ASSERT(inlineCapacity <= JSFinalObject::maxInlineCapacity());
 175     ASSERT(static_cast<PropertyOffset>(inlineCapacity) < firstOutOfLineOffset);
 176     ASSERT(!m_hasRareData);
 177     ASSERT(hasReadOnlyOrGetterSetterPropertiesExcludingProto() || !m_classInfo->hasStaticSetterOrReadonlyProperties(vm));
 178     ASSERT(hasGetterSetterProperties() || !m_classInfo->hasStaticSetterOrReadonlyProperties(vm));
 179 }
 180
 181 const ClassInfo Structure::s_info = { "Structure", 0, 0, 0, CREATE_METHOD_TABLE(Structure) };
 182
 183 Structure::Structure(VM& vm)
 184     : JSCell(CreatingEarlyCell)
 185     , m_prototype(vm, this, jsNull())
 186     , m_classInfo(info())
 187     , m_transitionWatchpointSet(IsWatched)
 188     , m_offset(invalidOffset)
 189     , m_inlineCapacity(0)
 190     , m_dictionaryKind(NoneDictionaryKind)
 191     , m_hasBeenFlattenedBefore(false)
 192     , m_isPinnedPropertyTable(false)
 193     , m_hasGetterSetterProperties(m_classInfo->hasStaticSetterOrReadonlyProperties(vm))
 194     , m_hasCustomGetterSetterProperties(false)
 195     , m_hasReadOnlyOrGetterSetterPropertiesExcludingProto(m_classInfo->hasStaticSetterOrReadonlyProperties(vm))
 196     , m_hasNonEnumerableProperties(false)
 197     , m_attributesInPrevious(0)
 198     , m_specificFunctionThrashCount(0)
 199     , m_preventExtensions(false)
 200     , m_didTransition(false)
 201     , m_staticFunctionReified(false)
 202     , m_hasRareData(false)
 203 {
 204     TypeInfo typeInfo = TypeInfo(CompoundType, OverridesVisitChildren | StructureIsImmortal);
 205     m_blob = StructureIDBlob(vm.heap.structureIDTable().allocateID(this), 0, typeInfo);
 206     m_outOfLineTypeFlags = typeInfo.outOfLineTypeFlags();
 207
 208     ASSERT(hasReadOnlyOrGetterSetterPropertiesExcludingProto() || !m_classInfo->hasStaticSetterOrReadonlyProperties(vm));
 209     ASSERT(hasGetterSetterProperties() || !m_classInfo->hasStaticSetterOrReadonlyProperties(vm));
 210 }
 211
 212 Structure::Structure(VM& vm, Structure* previous)
 213     : JSCell(vm, vm.structureStructure.get())
 214     , m_prototype(vm, this, previous->storedPrototype())
 215     , m_classInfo(previous->m_classInfo)
 216     , m_transitionWatchpointSet(IsWatched)
 217     , m_offset(invalidOffset)
 218     , m_inlineCapacity(previous->m_inlineCapacity)
 219     , m_dictionaryKind(previous->m_dictionaryKind)
 220     , m_hasBeenFlattenedBefore(previous->m_hasBeenFlattenedBefore)
 221     , m_isPinnedPropertyTable(false)
 222     , m_hasGetterSetterProperties(previous->m_hasGetterSetterProperties)
 223     , m_hasCustomGetterSetterProperties(previous->m_hasCustomGetterSetterProperties)
 224     , m_hasReadOnlyOrGetterSetterPropertiesExcludingProto(previous->m_hasReadOnlyOrGetterSetterPropertiesExcludingProto)
 225     , m_hasNonEnumerableProperties(previous->m_hasNonEnumerableProperties)
 226     , m_attributesInPrevious(0)
 227     , m_specificFunctionThrashCount(previous->m_specificFunctionThrashCount)
 228     , m_preventExtensions(previous->m_preventExtensions)
 229     , m_didTransition(true)
 230     , m_staticFunctionReified(previous->m_staticFunctionReified)
 231     , m_hasRareData(false)
 232 {
 233     TypeInfo typeInfo = previous->typeInfo();
 234     m_blob = StructureIDBlob(vm.heap.structureIDTable().allocateID(this), previous->indexingTypeIncludingHistory(), typeInfo);
 235     m_outOfLineTypeFlags = typeInfo.outOfLineTypeFlags();
 236
 237     ASSERT(!previous->typeInfo().structureIsImmortal());
 238     if (previous->m_hasRareData && previous->rareData()->needsCloning())
 239         cloneRareDataFrom(vm, previous);
 240     setPreviousID(vm, previous);
 241
 242     previous->notifyTransitionFromThisStructure();
 243     if (previous->m_globalObject)
 244         m_globalObject.set(vm, this, previous->m_globalObject.get());
 245     ASSERT(hasReadOnlyOrGetterSetterPropertiesExcludingProto() || !m_classInfo->hasStaticSetterOrReadonlyProperties(vm));
 246     ASSERT(hasGetterSetterProperties() || !m_classInfo->hasStaticSetterOrReadonlyProperties(vm));
 247 }
 248
 249 Structure::~Structure()
 250 {
 251     if (typeInfo().structureIsImmortal())
 252         return;
 253     Heap::heap(this)->structureIDTable().deallocateID(this, m_blob.structureID());
 254 }
 255
 256 void Structure::destroy(JSCell* cell)
 257 {
 258     static_cast<Structure*>(cell)->Structure::~Structure();
 259 }
 260
 261 void Structure::findStructuresAndMapForMaterialization(Vector<Structure*, 8>& structures, Structure*& structure, PropertyTable*& table)
 262 {
 263     ASSERT(structures.isEmpty());
 264     table = 0;
 265
 266     for (structure = this; structure; structure = structure->previousID()) {
 267         structure->m_lock.lock();
 268
 269         table = structure->propertyTable().get();
 270         if (table) {
 271             // Leave the structure locked, so that the caller can do things to it atomically
 272             // before it loses its property table.
 273             return;
 274         }
 275
 276         structures.append(structure);
 277         structure->m_lock.unlock();
 278     }
 279
 280     ASSERT(!structure);
 281     ASSERT(!table);
 282 }
 283
 284 void Structure::materializePropertyMap(VM& vm)
 285 {
 286     ASSERT(structure()->classInfo() == info());
 287     ASSERT(!propertyTable());
 288
 289     Vector<Structure*, 8> structures;
 290     Structure* structure;
 291     PropertyTable* table;
 292
 293     findStructuresAndMapForMaterialization(structures, structure, table);
 294
 295     if (table) {
 296         table = table->copy(vm, numberOfSlotsForLastOffset(m_offset, m_inlineCapacity));
 297         structure->m_lock.unlock();
 298     }
 299
 300     // Must hold the lock on this structure, since we will be modifying this structure's
 301     // property map. We don't want getConcurrently() to see the property map in a half-baked
 302     // state.
 303     GCSafeConcurrentJITLocker locker(m_lock, vm.heap);
 304     if (!table)
 305         createPropertyMap(locker, vm, numberOfSlotsForLastOffset(m_offset, m_inlineCapacity));
 306     else
 307         propertyTable().set(vm, this, table);
 308
 309     for (size_t i = structures.size(); i--;) {
 310         structure = structures[i];
 311         if (!structure->m_nameInPrevious)
 312             continue;
 313         PropertyMapEntry entry(vm, this, structure->m_nameInPrevious.get(), structure->m_offset, structure->m_attributesInPrevious, structure->m_specificValueInPrevious.get());
 314         propertyTable()->add(entry, m_offset, PropertyTable::PropertyOffsetMustNotChange);
 315     }
 316
 317     checkOffsetConsistency();
 318 }
 319
 320 void Structure::despecifyDictionaryFunction(VM& vm, PropertyName propertyName)
 321 {
 322     StringImpl* rep = propertyName.uid();
 323
 324     DeferGC deferGC(vm.heap);
 325     materializePropertyMapIfNecessary(vm, deferGC);
 326
 327     ASSERT(isDictionary());
 328     ASSERT(propertyTable());
 329
 330     PropertyMapEntry* entry = propertyTable()->get(rep);
 331     ASSERT(entry);
 332     entry->specificValue.clear();
 333 }
 334
 335 Structure* Structure::addPropertyTransitionToExistingStructureImpl(Structure* structure, StringImpl* uid, unsigned attributes, JSCell* specificValue, PropertyOffset& offset)
 336 {
 337     ASSERT(!structure->isDictionary());
 338     ASSERT(structure->isObject());
 339
 340     if (Structure* existingTransition = structure->m_transitionTable.get(uid, attributes)) {
 341         JSCell* specificValueInPrevious = existingTransition->m_specificValueInPrevious.get();
 342         if (specificValueInPrevious && specificValueInPrevious != specificValue)
 343             return 0;
 344         validateOffset(existingTransition->m_offset, existingTransition->inlineCapacity());
 345         offset = existingTransition->m_offset;
 346         return existingTransition;
 347     }
 348
 349     return 0;
 350 }
 351
 352 Structure* Structure::addPropertyTransitionToExistingStructure(Structure* structure, PropertyName propertyName, unsigned attributes, JSCell* specificValue, PropertyOffset& offset)
 353 {
 354     ASSERT(!isCompilationThread());
 355     return addPropertyTransitionToExistingStructureImpl(structure, propertyName.uid(), attributes, specificValue, offset);
 356 }
 357
 358 Structure* Structure::addPropertyTransitionToExistingStructureConcurrently(Structure* structure, StringImpl* uid, unsigned attributes, JSCell* specificValue, PropertyOffset& offset)
 359 {
 360     ConcurrentJITLocker locker(structure->m_lock);
 361     return addPropertyTransitionToExistingStructureImpl(structure, uid, attributes, specificValue, offset);
 362 }
 363
 364 bool Structure::anyObjectInChainMayInterceptIndexedAccesses() const
 365 {
 366     for (const Structure* current = this; ;) {
 367         if (current->mayInterceptIndexedAccesses())
 368             return true;
 369
 370         JSValue prototype = current->storedPrototype();
 371         if (prototype.isNull())
 372             return false;
 373
 374         current = asObject(prototype)->structure();
 375     }
 376 }
 377
 378 bool Structure::holesMustForwardToPrototype(VM& vm) const
 379 {
 380     if (this->mayInterceptIndexedAccesses())
 381         return true;
 382
 383     JSValue prototype = this->storedPrototype();
 384     if (!prototype.isObject())
 385         return false;
 386     JSObject* object = asObject(prototype);
 387
 388     while (true) {
 389         Structure& structure = *object->structure(vm);
 390         if (hasIndexedProperties(object->indexingType()) || structure.mayInterceptIndexedAccesses())
 391             return true;
 392         prototype = structure.storedPrototype();
 393         if (!prototype.isObject())
 394             return false;
 395         object = asObject(prototype);
 396     }
 397
 398     RELEASE_ASSERT_NOT_REACHED();
 399     return false;
 400 }
 401
 402 bool Structure::needsSlowPutIndexing() const
 403 {
 404     return anyObjectInChainMayInterceptIndexedAccesses()
 405         || globalObject()->isHavingABadTime();
 406 }
 407
 408 NonPropertyTransition Structure::suggestedArrayStorageTransition() const
 409 {
 410     if (needsSlowPutIndexing())
 411         return AllocateSlowPutArrayStorage;
 412
 413     return AllocateArrayStorage;
 414 }
 415
 416 Structure* Structure::addPropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, unsigned attributes, JSCell* specificValue, PropertyOffset& offset, PutPropertySlot::Context context)
 417 {
 418     // If we have a specific function, we may have got to this point if there is
 419     // already a transition with the correct property name and attributes, but
 420     // specialized to a different function.  In this case we just want to give up
 421     // and despecialize the transition.
 422     // In this case we clear the value of specificFunction which will result
 423     // in us adding a non-specific transition, and any subsequent lookup in
 424     // Structure::addPropertyTransitionToExistingStructure will just use that.
 425     if (specificValue && structure->m_transitionTable.contains(propertyName.uid(), attributes))
 426         specificValue = 0;
 427
 428     ASSERT(!structure->isDictionary());
 429     ASSERT(structure->isObject());
 430     ASSERT(!Structure::addPropertyTransitionToExistingStructure(structure, propertyName, attributes, specificValue, offset));
 431
 432     if (structure->m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
 433         specificValue = 0;
 434
 435     int maxTransitionLength;
 436     if (context == PutPropertySlot::PutById)
 437         maxTransitionLength = s_maxTransitionLengthForNonEvalPutById;
 438     else
 439         maxTransitionLength = s_maxTransitionLength;
 440     if (structure->transitionCount() > maxTransitionLength) {
 441         Structure* transition = toCacheableDictionaryTransition(vm, structure);
 442         ASSERT(structure != transition);
 443         offset = transition->putSpecificValue(vm, propertyName, attributes, specificValue);
 444         return transition;
 445     }
 446
 447     Structure* transition = create(vm, structure);
 448
 449     transition->m_cachedPrototypeChain.setMayBeNull(vm, transition, structure->m_cachedPrototypeChain.get());
 450     transition->m_nameInPrevious = propertyName.uid();
 451     transition->m_attributesInPrevious = attributes;
 452     transition->m_specificValueInPrevious.setMayBeNull(vm, transition, specificValue);
 453     transition->propertyTable().set(vm, transition, structure->takePropertyTableOrCloneIfPinned(vm));
 454     transition->m_offset = structure->m_offset;
 455
 456     offset = transition->putSpecificValue(vm, propertyName, attributes, specificValue);
 457
 458     checkOffset(transition->m_offset, transition->inlineCapacity());
 459     {
 460         ConcurrentJITLocker locker(structure->m_lock);
 461         structure->m_transitionTable.add(vm, transition);
 462     }
 463     transition->checkOffsetConsistency();
 464     structure->checkOffsetConsistency();
 465     return transition;
 466 }
 467
 468 Structure* Structure::removePropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, PropertyOffset& offset)
 469 {
 470     ASSERT(!structure->isUncacheableDictionary());
 471
 472     Structure* transition = toUncacheableDictionaryTransition(vm, structure);
 473
 474     offset = transition->remove(propertyName);
 475
 476     transition->checkOffsetConsistency();
 477     return transition;
 478 }
 479
 480 Structure* Structure::changePrototypeTransition(VM& vm, Structure* structure, JSValue prototype)
 481 {
 482     Structure* transition = create(vm, structure);
 483
 484     transition->m_prototype.set(vm, transition, prototype);
 485
 486     DeferGC deferGC(vm.heap);
 487     structure->materializePropertyMapIfNecessary(vm, deferGC);
 488     transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
 489     transition->m_offset = structure->m_offset;
 490     transition->pin();
 491
 492     transition->checkOffsetConsistency();
 493     return transition;
 494 }
 495
 496 Structure* Structure::despecifyFunctionTransition(VM& vm, Structure* structure, PropertyName replaceFunction)
 497 {
 498     ASSERT(structure->m_specificFunctionThrashCount < maxSpecificFunctionThrashCount);
 499     Structure* transition = create(vm, structure);
 500
 501     ++transition->m_specificFunctionThrashCount;
 502
 503     DeferGC deferGC(vm.heap);
 504     structure->materializePropertyMapIfNecessary(vm, deferGC);
 505     transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
 506     transition->m_offset = structure->m_offset;
 507     transition->pin();
 508
 509     if (transition->m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
 510         transition->despecifyAllFunctions(vm);
 511     else {
 512         bool removed = transition->despecifyFunction(vm, replaceFunction);
 513         ASSERT_UNUSED(removed, removed);
 514     }
 515
 516     transition->checkOffsetConsistency();
 517     return transition;
 518 }
 519
 520 Structure* Structure::attributeChangeTransition(VM& vm, Structure* structure, PropertyName propertyName, unsigned attributes)
 521 {
 522     DeferGC deferGC(vm.heap);
 523     if (!structure->isUncacheableDictionary()) {
 524         Structure* transition = create(vm, structure);
 525
 526         structure->materializePropertyMapIfNecessary(vm, deferGC);
 527         transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
 528         transition->m_offset = structure->m_offset;
 529         transition->pin();
 530
 531         structure = transition;
 532     }
 533
 534     ASSERT(structure->propertyTable());
 535     PropertyMapEntry* entry = structure->propertyTable()->get(propertyName.uid());
 536     ASSERT(entry);
 537     entry->attributes = attributes;
 538
 539     structure->checkOffsetConsistency();
 540     return structure;
 541 }
 542
 543 Structure* Structure::toDictionaryTransition(VM& vm, Structure* structure, DictionaryKind kind)
 544 {
 545     ASSERT(!structure->isUncacheableDictionary());
 546
 547     Structure* transition = create(vm, structure);
 548
 549     DeferGC deferGC(vm.heap);
 550     structure->materializePropertyMapIfNecessary(vm, deferGC);
 551     transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
 552     transition->m_offset = structure->m_offset;
 553     transition->m_dictionaryKind = kind;
 554     transition->pin();
 555
 556     transition->checkOffsetConsistency();
 557     return transition;
 558 }
 559
 560 Structure* Structure::toCacheableDictionaryTransition(VM& vm, Structure* structure)
 561 {
 562     return toDictionaryTransition(vm, structure, CachedDictionaryKind);
 563 }
 564
 565 Structure* Structure::toUncacheableDictionaryTransition(VM& vm, Structure* structure)
 566 {
 567     return toDictionaryTransition(vm, structure, UncachedDictionaryKind);
 568 }
 569
 570 // In future we may want to cache this transition.
 571 Structure* Structure::sealTransition(VM& vm, Structure* structure)
 572 {
 573     Structure* transition = preventExtensionsTransition(vm, structure);
 574
 575     if (transition->propertyTable()) {
 576         PropertyTable::iterator end = transition->propertyTable()->end();
 577         for (PropertyTable::iterator iter = transition->propertyTable()->begin(); iter != end; ++iter)
 578             iter->attributes |= DontDelete;
 579     }
 580
 581     transition->checkOffsetConsistency();
 582     return transition;
 583 }
 584
 585 // In future we may want to cache this transition.
 586 Structure* Structure::freezeTransition(VM& vm, Structure* structure)
 587 {
 588     Structure* transition = preventExtensionsTransition(vm, structure);
 589
 590     if (transition->propertyTable()) {
 591         PropertyTable::iterator iter = transition->propertyTable()->begin();
 592         PropertyTable::iterator end = transition->propertyTable()->end();
 593         if (iter != end)
 594             transition->m_hasReadOnlyOrGetterSetterPropertiesExcludingProto = true;
 595         for (; iter != end; ++iter)
 596             iter->attributes |= iter->attributes & Accessor ? DontDelete : (DontDelete | ReadOnly);
 597     }
 598
 599     ASSERT(transition->hasReadOnlyOrGetterSetterPropertiesExcludingProto() || !transition->classInfo()->hasStaticSetterOrReadonlyProperties(vm));
 600     ASSERT(transition->hasGetterSetterProperties() || !transition->classInfo()->hasStaticSetterOrReadonlyProperties(vm));
 601     transition->checkOffsetConsistency();
 602     return transition;
 603 }
 604
 605 // In future we may want to cache this transition.
 606 Structure* Structure::preventExtensionsTransition(VM& vm, Structure* structure)
 607 {
 608     Structure* transition = create(vm, structure);
 609
 610     // Don't set m_offset, as one can not transition to this.
 611
 612     DeferGC deferGC(vm.heap);
 613     structure->materializePropertyMapIfNecessary(vm, deferGC);
 614     transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
 615     transition->m_offset = structure->m_offset;
 616     transition->m_preventExtensions = true;
 617     transition->pin();
 618
 619     transition->checkOffsetConsistency();
 620     return transition;
 621 }
 622
 623 PropertyTable* Structure::takePropertyTableOrCloneIfPinned(VM& vm)
 624 {
 625     DeferGC deferGC(vm.heap);
 626     materializePropertyMapIfNecessaryForPinning(vm, deferGC);
 627
 628     if (m_isPinnedPropertyTable)
 629         return propertyTable()->copy(vm, propertyTable()->size() + 1);
 630
 631     // Hold the lock while stealing the table - so that getConcurrently() on another thread
 632     // will either have to bypass this structure, or will get to use the property table
 633     // before it is stolen.
 634     ConcurrentJITLocker locker(m_lock);
 635     PropertyTable* takenPropertyTable = propertyTable().get();
 636     propertyTable().clear();
 637     return takenPropertyTable;
 638 }
 639
 640 Structure* Structure::nonPropertyTransition(VM& vm, Structure* structure, NonPropertyTransition transitionKind)
 641 {
 642     unsigned attributes = toAttributes(transitionKind);
 643     IndexingType indexingType = newIndexingType(structure->indexingTypeIncludingHistory(), transitionKind);
 644
 645     if (JSGlobalObject* globalObject = structure->m_globalObject.get()) {
 646         if (globalObject->isOriginalArrayStructure(structure)) {
 647             Structure* result = globalObject->originalArrayStructureForIndexingType(indexingType);
 648             if (result->indexingTypeIncludingHistory() == indexingType) {
 649                 structure->notifyTransitionFromThisStructure();
 650                 return result;
 651             }
 652         }
 653     }
 654
 655     Structure* existingTransition;
 656     if (!structure->isDictionary() && (existingTransition = structure->m_transitionTable.get(0, attributes))) {
 657         ASSERT(existingTransition->m_attributesInPrevious == attributes);
 658         ASSERT(existingTransition->indexingTypeIncludingHistory() == indexingType);
 659         return existingTransition;
 660     }
 661
 662     Structure* transition = create(vm, structure);
 663     transition->m_attributesInPrevious = attributes;
 664     transition->m_blob.setIndexingType(indexingType);
 665     transition->propertyTable().set(vm, transition, structure->takePropertyTableOrCloneIfPinned(vm));
 666     transition->m_offset = structure->m_offset;
 667     checkOffset(transition->m_offset, transition->inlineCapacity());
 668
 669     if (structure->isDictionary())
 670         transition->pin();
 671     else {
 672         ConcurrentJITLocker locker(structure->m_lock);
 673         structure->m_transitionTable.add(vm, transition);
 674     }
 675     transition->checkOffsetConsistency();
 676     return transition;
 677 }
 678
 679 // In future we may want to cache this property.
 680 bool Structure::isSealed(VM& vm)
 681 {
 682     if (isExtensible())
 683         return false;
 684
 685     DeferGC deferGC(vm.heap);
 686     materializePropertyMapIfNecessary(vm, deferGC);
 687     if (!propertyTable())
 688         return true;
 689
 690     PropertyTable::iterator end = propertyTable()->end();
 691     for (PropertyTable::iterator iter = propertyTable()->begin(); iter != end; ++iter) {
 692         if ((iter->attributes & DontDelete) != DontDelete)
 693             return false;
 694     }
 695     return true;
 696 }
 697
 698 // In future we may want to cache this property.
 699 bool Structure::isFrozen(VM& vm)
 700 {
 701     if (isExtensible())
 702         return false;
 703
 704     DeferGC deferGC(vm.heap);
 705     materializePropertyMapIfNecessary(vm, deferGC);
 706     if (!propertyTable())
 707         return true;
 708
 709     PropertyTable::iterator end = propertyTable()->end();
 710     for (PropertyTable::iterator iter = propertyTable()->begin(); iter != end; ++iter) {
 711         if (!(iter->attributes & DontDelete))
 712             return false;
 713         if (!(iter->attributes & (ReadOnly | Accessor)))
 714             return false;
 715     }
 716     return true;
 717 }
 718
 719 Structure* Structure::flattenDictionaryStructure(VM& vm, JSObject* object)
 720 {
 721     checkOffsetConsistency();
 722     ASSERT(isDictionary());
 723
 724     size_t beforeOutOfLineCapacity = this->outOfLineCapacity();
 725     if (isUncacheableDictionary()) {
 726         ASSERT(propertyTable());
 727
 728         size_t propertyCount = propertyTable()->size();
 729
 730         // Holds our values compacted by insertion order.
 731         Vector<JSValue> values(propertyCount);
 732
 733         // Copies out our values from their hashed locations, compacting property table offsets as we go.
 734         unsigned i = 0;
 735         PropertyTable::iterator end = propertyTable()->end();
 736         m_offset = invalidOffset;
 737         for (PropertyTable::iterator iter = propertyTable()->begin(); iter != end; ++iter, ++i) {
 738             values[i] = object->getDirect(iter->offset);
 739             m_offset = iter->offset = offsetForPropertyNumber(i, m_inlineCapacity);
 740         }
 741
 742         // Copies in our values to their compacted locations.
 743         for (unsigned i = 0; i < propertyCount; i++)
 744             object->putDirect(vm, offsetForPropertyNumber(i, m_inlineCapacity), values[i]);
 745
 746         propertyTable()->clearDeletedOffsets();
 747         checkOffsetConsistency();
 748     }
 749
 750     m_dictionaryKind = NoneDictionaryKind;
 751     m_hasBeenFlattenedBefore = true;
 752
 753     size_t afterOutOfLineCapacity = this->outOfLineCapacity();
 754
 755     if (beforeOutOfLineCapacity != afterOutOfLineCapacity) {
 756         ASSERT(beforeOutOfLineCapacity > afterOutOfLineCapacity);
 757         // If the object had a Butterfly but after flattening/compacting we no longer have need of it,
 758         // we need to zero it out because the collector depends on the Structure to know the size for copying.
 759         if (object->butterfly() && !afterOutOfLineCapacity && !this->hasIndexingHeader(object))
 760             object->setStructureAndButterfly(vm, this, 0);
 761         // If the object was down-sized to the point where the base of the Butterfly is no longer within the
 762         // first CopiedBlock::blockSize bytes, we'll get the wrong answer if we try to mask the base back to
 763         // the CopiedBlock header. To prevent this case we need to memmove the Butterfly down.
 764         else if (object->butterfly())
 765             object->shiftButterflyAfterFlattening(vm, beforeOutOfLineCapacity, afterOutOfLineCapacity);
 766     }
 767
 768     return this;
 769 }
 770
 771 PropertyOffset Structure::addPropertyWithoutTransition(VM& vm, PropertyName propertyName, unsigned attributes, JSCell* specificValue)
 772 {
 773     ASSERT(!enumerationCache());
 774
 775     if (m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
 776         specificValue = 0;
 777
 778     DeferGC deferGC(vm.heap);
 779     materializePropertyMapIfNecessaryForPinning(vm, deferGC);
 780
 781     pin();
 782
 783     return putSpecificValue(vm, propertyName, attributes, specificValue);
 784 }
 785
 786 PropertyOffset Structure::removePropertyWithoutTransition(VM& vm, PropertyName propertyName)
 787 {
 788     ASSERT(isUncacheableDictionary());
 789     ASSERT(!enumerationCache());
 790
 791     DeferGC deferGC(vm.heap);
 792     materializePropertyMapIfNecessaryForPinning(vm, deferGC);
 793
 794     pin();
 795     return remove(propertyName);
 796 }
 797
 798 void Structure::pin()
 799 {
 800     ASSERT(propertyTable());
 801     m_isPinnedPropertyTable = true;
 802     clearPreviousID();
 803     m_nameInPrevious.clear();
 804 }
 805
 806 void Structure::allocateRareData(VM& vm)
 807 {
 808     ASSERT(!m_hasRareData);
 809     StructureRareData* rareData = StructureRareData::create(vm, previous());
 810     m_previousOrRareData.set(vm, this, rareData);
 811     m_hasRareData = true;
 812     ASSERT(m_hasRareData);
 813 }
 814
 815 void Structure::cloneRareDataFrom(VM& vm, const Structure* other)
 816 {
 817     ASSERT(!m_hasRareData);
 818     ASSERT(other->m_hasRareData);
 819     StructureRareData* newRareData = StructureRareData::clone(vm, other->rareData());
 820     m_previousOrRareData.set(vm, this, newRareData);
 821     m_hasRareData = true;
 822     ASSERT(m_hasRareData);
 823 }
 824
 825 #if DUMP_PROPERTYMAP_STATS
 826
 827 PropertyMapHashTableStats* propertyMapHashTableStats = 0;
 828
 829 struct PropertyMapStatisticsExitLogger {
 830     PropertyMapStatisticsExitLogger();
 831     ~PropertyMapStatisticsExitLogger();
 832 };
 833
 834 DEFINE_GLOBAL_FOR_LOGGING(PropertyMapStatisticsExitLogger, logger, );
 835
 836 PropertyMapStatisticsExitLogger::PropertyMapStatisticsExitLogger()
 837 {
 838     propertyMapHashTableStats = adoptPtr(new PropertyMapHashTableStats()).leakPtr();
 839 }
 840
 841 PropertyMapStatisticsExitLogger::~PropertyMapStatisticsExitLogger()
 842 {
 843     unsigned finds = propertyMapHashTableStats->numFinds;
 844     unsigned collisions = propertyMapHashTableStats->numCollisions;
 845     dataLogF("\nJSC::PropertyMap statistics for process %d\n\n", getCurrentProcessID());
 846     dataLogF("%d finds\n", finds);
 847     dataLogF("%d collisions (%.1f%%)\n", collisions, 100.0 * collisions / finds);
 848     dataLogF("%d lookups\n", propertyMapHashTableStats->numLookups.load());
 849     dataLogF("%d lookup probings\n", propertyMapHashTableStats->numLookupProbing.load());
 850     dataLogF("%d adds\n", propertyMapHashTableStats->numAdds.load());
 851     dataLogF("%d removes\n", propertyMapHashTableStats->numRemoves.load());
 852     dataLogF("%d rehashes\n", propertyMapHashTableStats->numRehashes.load());
 853     dataLogF("%d reinserts\n", propertyMapHashTableStats->numReinserts.load());
 854 }
 855
 856 #endif
 857
 858 #if !DO_PROPERTYMAP_CONSTENCY_CHECK
 859
 860 inline void Structure::checkConsistency()
 861 {
 862     checkOffsetConsistency();
 863 }
 864
 865 #endif
 866
 867 PropertyTable* Structure::copyPropertyTable(VM& vm)
 868 {
 869     if (!propertyTable())
 870         return 0;
 871     return PropertyTable::clone(vm, *propertyTable().get());
 872 }
 873
 874 PropertyTable* Structure::copyPropertyTableForPinning(VM& vm)
 875 {
 876     if (propertyTable())
 877         return PropertyTable::clone(vm, *propertyTable().get());
 878     return PropertyTable::create(vm, numberOfSlotsForLastOffset(m_offset, m_inlineCapacity));
 879 }
 880
 881 PropertyOffset Structure::getConcurrently(VM&, StringImpl* uid, unsigned& attributes, JSCell*& specificValue)
 882 {
 883     Vector<Structure*, 8> structures;
 884     Structure* structure;
 885     PropertyTable* table;
 886
 887     findStructuresAndMapForMaterialization(structures, structure, table);
 888
 889     if (table) {
 890         PropertyMapEntry* entry = table->get(uid);
 891         if (entry) {
 892             attributes = entry->attributes;
 893             specificValue = entry->specificValue.get();
 894             PropertyOffset result = entry->offset;
 895             structure->m_lock.unlock();
 896             return result;
 897         }
 898         structure->m_lock.unlock();
 899     }
 900
 901     for (unsigned i = structures.size(); i--;) {
 902         structure = structures[i];
 903         if (structure->m_nameInPrevious.get() != uid)
 904             continue;
 905
 906         attributes = structure->m_attributesInPrevious;
 907         specificValue = structure->m_specificValueInPrevious.get();
 908         return structure->m_offset;
 909     }
 910
 911     return invalidOffset;
 912 }
 913
 914 bool Structure::despecifyFunction(VM& vm, PropertyName propertyName)
 915 {
 916     DeferGC deferGC(vm.heap);
 917     materializePropertyMapIfNecessary(vm, deferGC);
 918     if (!propertyTable())
 919         return false;
 920
 921     PropertyMapEntry* entry = propertyTable()->get(propertyName.uid());
 922     if (!entry)
 923         return false;
 924
 925     ASSERT(entry->specificValue);
 926     entry->specificValue.clear();
 927     return true;
 928 }
 929
 930 void Structure::despecifyAllFunctions(VM& vm)
 931 {
 932     DeferGC deferGC(vm.heap);
 933     materializePropertyMapIfNecessary(vm, deferGC);
 934     if (!propertyTable())
 935         return;
 936
 937     PropertyTable::iterator end = propertyTable()->end();
 938     for (PropertyTable::iterator iter = propertyTable()->begin(); iter != end; ++iter)
 939         iter->specificValue.clear();
 940 }
 941
 942 PropertyOffset Structure::putSpecificValue(VM& vm, PropertyName propertyName, unsigned attributes, JSCell* specificValue)
 943 {
 944     GCSafeConcurrentJITLocker locker(m_lock, vm.heap);
 945
 946     ASSERT(!JSC::isValidOffset(get(vm, propertyName)));
 947
 948     checkConsistency();
 949     if (attributes & DontEnum)
 950         m_hasNonEnumerableProperties = true;
 951
 952     StringImpl* rep = propertyName.uid();
 953
 954     if (!propertyTable())
 955         createPropertyMap(locker, vm);
 956
 957     PropertyOffset newOffset = propertyTable()->nextOffset(m_inlineCapacity);
 958
 959     propertyTable()->add(PropertyMapEntry(vm, propertyTable().get(), rep, newOffset, attributes, specificValue), m_offset, PropertyTable::PropertyOffsetMayChange);
 960
 961     checkConsistency();
 962     return newOffset;
 963 }
 964
 965 PropertyOffset Structure::remove(PropertyName propertyName)
 966 {
 967     ConcurrentJITLocker locker(m_lock);
 968
 969     checkConsistency();
 970
 971     StringImpl* rep = propertyName.uid();
 972
 973     if (!propertyTable())
 974         return invalidOffset;
 975
 976     PropertyTable::find_iterator position = propertyTable()->find(rep);
 977     if (!position.first)
 978         return invalidOffset;
 979
 980     PropertyOffset offset = position.first->offset;
 981
 982     propertyTable()->remove(position);
 983     propertyTable()->addDeletedOffset(offset);
 984
 985     checkConsistency();
 986     return offset;
 987 }
 988
 989 void Structure::createPropertyMap(const GCSafeConcurrentJITLocker&, VM& vm, unsigned capacity)
 990 {
 991     ASSERT(!propertyTable());
 992
 993     checkConsistency();
 994     propertyTable().set(vm, this, PropertyTable::create(vm, capacity));
 995 }
 996
 997 void Structure::getPropertyNamesFromStructure(VM& vm, PropertyNameArray& propertyNames, EnumerationMode mode)
 998 {
 999     DeferGC deferGC(vm.heap);
1000     materializePropertyMapIfNecessary(vm, deferGC);
1001     if (!propertyTable())
1002         return;
1003
1004     bool knownUnique = !propertyNames.size();
1005
1006     PropertyTable::iterator end = propertyTable()->end();
1007     for (PropertyTable::iterator iter = propertyTable()->begin(); iter != end; ++iter) {
1008         ASSERT(m_hasNonEnumerableProperties || !(iter->attributes & DontEnum));
1009         if (!iter->key->isEmptyUnique() && (!(iter->attributes & DontEnum) || mode == IncludeDontEnumProperties)) {
1010             if (knownUnique)
1011                 propertyNames.addKnownUnique(iter->key);
1012             else
1013                 propertyNames.add(iter->key);
1014         }
1015     }
1016 }
1017
1018 JSValue Structure::prototypeForLookup(CodeBlock* codeBlock) const
1019 {
1020     return prototypeForLookup(codeBlock->globalObject());
1021 }
1022
1023 void Structure::visitChildren(JSCell* cell, SlotVisitor& visitor)
1024 {
1025     Structure* thisObject = jsCast<Structure*>(cell);
1026     ASSERT_GC_OBJECT_INHERITS(thisObject, info());
1027     ASSERT(thisObject->structure()->typeInfo().overridesVisitChildren());
1028
1029     JSCell::visitChildren(thisObject, visitor);
1030     visitor.append(&thisObject->m_globalObject);
1031     if (!thisObject->isObject())
1032         thisObject->m_cachedPrototypeChain.clear();
1033     else {
1034         visitor.append(&thisObject->m_prototype);
1035         visitor.append(&thisObject->m_cachedPrototypeChain);
1036     }
1037     visitor.append(&thisObject->m_previousOrRareData);
1038     visitor.append(&thisObject->m_specificValueInPrevious);
1039
1040     if (thisObject->m_isPinnedPropertyTable) {
1041         ASSERT(thisObject->m_propertyTableUnsafe);
1042         visitor.append(&thisObject->m_propertyTableUnsafe);
1043     } else if (thisObject->m_propertyTableUnsafe)
1044         thisObject->m_propertyTableUnsafe.clear();
1045 }
1046
1047 bool Structure::prototypeChainMayInterceptStoreTo(VM& vm, PropertyName propertyName)
1048 {
1049     unsigned i = propertyName.asIndex();
1050     if (i != PropertyName::NotAnIndex)
1051         return anyObjectInChainMayInterceptIndexedAccesses();
1052
1053     for (Structure* current = this; ;) {
1054         JSValue prototype = current->storedPrototype();
1055         if (prototype.isNull())
1056             return false;
1057
1058         current = prototype.asCell()->structure(vm);
1059
1060         unsigned attributes;
1061         JSCell* specificValue;
1062         PropertyOffset offset = current->get(vm, propertyName, attributes, specificValue);
1063         if (!JSC::isValidOffset(offset))
1064             continue;
1065
1066         if (attributes & (ReadOnly | Accessor))
1067             return true;
1068
1069         return false;
1070     }
1071 }
1072
1073 void Structure::dump(PrintStream& out) const
1074 {
1075     out.print(RawPointer(this), ":[", classInfo()->className, ", {");
1076
1077     Vector<Structure*, 8> structures;
1078     Structure* structure;
1079     PropertyTable* table;
1080
1081     const_cast<Structure*>(this)->findStructuresAndMapForMaterialization(
1082         structures, structure, table);
1083
1084     CommaPrinter comma;
1085
1086     if (table) {
1087         PropertyTable::iterator iter = table->begin();
1088         PropertyTable::iterator end = table->end();
1089         for (; iter != end; ++iter) {
1090             out.print(comma, iter->key, ":", static_cast<int>(iter->offset));
1091             if (iter->specificValue) {
1092                 DumpContext dummyContext;
1093                 out.print("=>", RawPointer(iter->specificValue.get()));
1094             }
1095         }
1096
1097         structure->m_lock.unlock();
1098     }
1099
1100     for (unsigned i = structures.size(); i--;) {
1101         Structure* structure = structures[i];
1102         if (!structure->m_nameInPrevious)
1103             continue;
1104         out.print(comma, structure->m_nameInPrevious.get(), ":", static_cast<int>(structure->m_offset));
1105         if (structure->m_specificValueInPrevious) {
1106             DumpContext dummyContext;
1107             out.print("=>", RawPointer(structure->m_specificValueInPrevious.get()));
1108         }
1109     }
1110
1111     out.print("}, ", IndexingTypeDump(indexingType()));
1112
1113     if (m_prototype.get().isCell())
1114         out.print(", Proto:", RawPointer(m_prototype.get().asCell()));
1115
1116     out.print("]");
1117 }
1118
1119 void Structure::dumpInContext(PrintStream& out, DumpContext* context) const
1120 {
1121     if (context)
1122         context->structures.dumpBrief(this, out);
1123     else
1124         dump(out);
1125 }
1126
1127 void Structure::dumpBrief(PrintStream& out, const CString& string) const
1128 {
1129     out.print("%", string, ":", classInfo()->className);
1130 }
1131
1132 void Structure::dumpContextHeader(PrintStream& out)
1133 {
1134     out.print("Structures:");
1135 }
1136
1137 #if DO_PROPERTYMAP_CONSTENCY_CHECK
1138
1139 void PropertyTable::checkConsistency()
1140 {
1141     checkOffsetConsistency();
1142     ASSERT(m_indexSize >= PropertyTable::MinimumTableSize);
1143     ASSERT(m_indexMask);
1144     ASSERT(m_indexSize == m_indexMask + 1);
1145     ASSERT(!(m_indexSize & m_indexMask));
1146
1147     ASSERT(m_keyCount <= m_indexSize / 2);
1148     ASSERT(m_keyCount + m_deletedCount <= m_indexSize / 2);
1149     ASSERT(m_deletedCount <= m_indexSize / 4);
1150
1151     unsigned indexCount = 0;
1152     unsigned deletedIndexCount = 0;
1153     for (unsigned a = 0; a != m_indexSize; ++a) {
1154         unsigned entryIndex = m_index[a];
1155         if (entryIndex == PropertyTable::EmptyEntryIndex)
1156             continue;
1157         if (entryIndex == deletedEntryIndex()) {
1158             ++deletedIndexCount;
1159             continue;
1160         }
1161         ASSERT(entryIndex < deletedEntryIndex());
1162         ASSERT(entryIndex - 1 <= usedCount());
1163         ++indexCount;
1164
1165         for (unsigned b = a + 1; b != m_indexSize; ++b)
1166             ASSERT(m_index[b] != entryIndex);
1167     }
1168     ASSERT(indexCount == m_keyCount);
1169     ASSERT(deletedIndexCount == m_deletedCount);
1170
1171     ASSERT(!table()[deletedEntryIndex() - 1].key);
1172
1173     unsigned nonEmptyEntryCount = 0;
1174     for (unsigned c = 0; c < usedCount(); ++c) {
1175         StringImpl* rep = table()[c].key;
1176         if (rep == PROPERTY_MAP_DELETED_ENTRY_KEY)
1177             continue;
1178         ++nonEmptyEntryCount;
1179         unsigned i = rep->existingHash();
1180         unsigned k = 0;
1181         unsigned entryIndex;
1182         while (1) {
1183             entryIndex = m_index[i & m_indexMask];
1184             ASSERT(entryIndex != PropertyTable::EmptyEntryIndex);
1185             if (rep == table()[entryIndex - 1].key)
1186                 break;
1187             if (k == 0)
1188                 k = 1 | doubleHash(rep->existingHash());
1189             i += k;
1190         }
1191         ASSERT(entryIndex == c + 1);
1192     }
1193
1194     ASSERT(nonEmptyEntryCount == m_keyCount);
1195 }
1196
1197 void Structure::checkConsistency()
1198 {
1199     if (!propertyTable())
1200         return;
1201
1202     if (!m_hasNonEnumerableProperties) {
1203         PropertyTable::iterator end = propertyTable()->end();
1204         for (PropertyTable::iterator iter = propertyTable()->begin(); iter != end; ++iter) {
1205             ASSERT(!(iter->attributes & DontEnum));
1206         }
1207     }
1208
1209     propertyTable()->checkConsistency();
1210 }
1211
1212 #endif // DO_PROPERTYMAP_CONSTENCY_CHECK
1213
1214 bool ClassInfo::hasStaticSetterOrReadonlyProperties(VM& vm) const
1215 {
1216     for (const ClassInfo* ci = this; ci; ci = ci->parentClass) {
1217         if (const HashTable* table = ci->propHashTable(vm)) {
1218             if (table->hasSetterOrReadonlyProperties)
1219                 return true;
1220         }
1221     }
1222     return false;
1223 }
1224
1225 } // namespace JSC