Example #1
0
Structure* Structure::nonPropertyTransition(JSGlobalData& globalData, Structure* structure, NonPropertyTransition transitionKind)
{
    unsigned attributes = toAttributes(transitionKind);
    IndexingType indexingType = newIndexingType(structure->indexingTypeIncludingHistory(), transitionKind);
    
    if (JSGlobalObject* globalObject = structure->m_globalObject.get()) {
        if (globalObject->isOriginalArrayStructure(structure)) {
            Structure* result = globalObject->originalArrayStructureForIndexingType(indexingType);
            if (result->indexingTypeIncludingHistory() == indexingType) {
                structure->notifyTransitionFromThisStructure();
                return result;
            }
        }
    }
    
    if (Structure* existingTransition = structure->m_transitionTable.get(0, attributes)) {
        ASSERT(existingTransition->m_attributesInPrevious == attributes);
        ASSERT(existingTransition->indexingTypeIncludingHistory() == indexingType);
        return existingTransition;
    }
    
    Structure* transition = create(globalData, structure);
    transition->setPreviousID(globalData, transition, structure);
    transition->m_attributesInPrevious = attributes;
    transition->m_indexingType = indexingType;
    transition->propertyTable().set(globalData, transition, structure->takePropertyTableOrCloneIfPinned(globalData, transition));
    transition->m_offset = structure->m_offset;
    checkOffset(transition->m_offset, transition->inlineCapacity());
    
    structure->m_transitionTable.add(globalData, transition);
    transition->checkOffsetConsistency();
    return transition;
}
Example #2
0
Structure* Structure::removePropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, PropertyOffset& offset)
{
    // NOTE: There are some good reasons why this goes directly to uncacheable dictionary rather than
    // caching the removal. We can fix all of these things, but we must remember to do so, if we ever try
    // to optimize this case.
    //
    // - Cached transitions usually steal the property table, and assume that this is possible because they
    //   can just rebuild the table by looking at past transitions. That code assumes that the table only
    //   grew and never shrank. To support removals, we'd have to change the property table materialization
    //   code to handle deletions. Also, we have logic to get the list of properties on a structure that
    //   lacks a property table by just looking back through the set of transitions since the last
    //   structure that had a pinned table. That logic would also have to be changed to handle cached
    //   removals.
    //
    // - InferredTypeTable assumes that removal has never happened. This is important since if we could
    //   remove a property and then re-add it later, then the "absence means top" optimization wouldn't
    //   work anymore, unless removal also either poisoned type inference (by doing something equivalent to
    //   hasBeenDictionary) or by strongly marking the entry as Top by ensuring that it is not absent, but
    //   instead, has a null entry.

    ASSERT(!structure->isUncacheableDictionary());

    Structure* transition = toUncacheableDictionaryTransition(vm, structure);

    offset = transition->remove(propertyName);

    transition->checkOffsetConsistency();
    return transition;
}
Example #3
0
Structure* Structure::removePropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, PropertyOffset& offset)
{
    ASSERT(!structure->isUncacheableDictionary());

    Structure* transition = toUncacheableDictionaryTransition(vm, structure);

    offset = transition->remove(propertyName);

    transition->checkOffsetConsistency();
    return transition;
}
Example #4
0
// In future we may want to cache this transition.
Structure* Structure::sealTransition(VM& vm, Structure* structure)
{
    Structure* transition = preventExtensionsTransition(vm, structure);

    if (transition->propertyTable()) {
        PropertyTable::iterator end = transition->propertyTable()->end();
        for (PropertyTable::iterator iter = transition->propertyTable()->begin(); iter != end; ++iter)
            iter->attributes |= DontDelete;
    }

    transition->checkOffsetConsistency();
    return transition;
}
Example #5
0
Structure* Structure::changePrototypeTransition(JSGlobalData& globalData, Structure* structure, JSValue prototype)
{
    Structure* transition = create(globalData, structure);

    transition->m_prototype.set(globalData, transition, prototype);

    structure->materializePropertyMapIfNecessary(globalData);
    transition->propertyTable().set(globalData, transition, structure->copyPropertyTableForPinning(globalData, transition));
    transition->m_offset = structure->m_offset;
    transition->pin();

    transition->checkOffsetConsistency();
    return transition;
}
Example #6
0
Structure* Structure::changePrototypeTransition(VM& vm, Structure* structure, JSValue prototype)
{
    Structure* transition = create(vm, structure);

    transition->m_prototype.set(vm, transition, prototype);

    DeferGC deferGC(vm.heap);
    structure->materializePropertyMapIfNecessary(vm, deferGC);
    transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
    transition->m_offset = structure->m_offset;
    transition->pin();

    transition->checkOffsetConsistency();
    return transition;
}
Example #7
0
Structure* Structure::toDictionaryTransition(JSGlobalData& globalData, Structure* structure, DictionaryKind kind)
{
    ASSERT(!structure->isUncacheableDictionary());
    
    Structure* transition = create(globalData, structure);

    structure->materializePropertyMapIfNecessary(globalData);
    transition->propertyTable().set(globalData, transition, structure->copyPropertyTableForPinning(globalData, transition));
    transition->m_offset = structure->m_offset;
    transition->m_dictionaryKind = kind;
    transition->pin();

    transition->checkOffsetConsistency();
    return transition;
}
Example #8
0
// In future we may want to cache this transition.
Structure* Structure::preventExtensionsTransition(JSGlobalData& globalData, Structure* structure)
{
    Structure* transition = create(globalData, structure);

    // Don't set m_offset, as one can not transition to this.

    structure->materializePropertyMapIfNecessary(globalData);
    transition->propertyTable().set(globalData, transition, structure->copyPropertyTableForPinning(globalData, transition));
    transition->m_offset = structure->m_offset;
    transition->m_preventExtensions = true;
    transition->pin();

    transition->checkOffsetConsistency();
    return transition;
}
Example #9
0
Structure* Structure::toDictionaryTransition(VM& vm, Structure* structure, DictionaryKind kind)
{
    ASSERT(!structure->isUncacheableDictionary());
    
    Structure* transition = create(vm, structure);

    DeferGC deferGC(vm.heap);
    structure->materializePropertyMapIfNecessary(vm, deferGC);
    transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
    transition->m_offset = structure->m_offset;
    transition->setDictionaryKind(kind);
    transition->pin();

    transition->checkOffsetConsistency();
    return transition;
}
Example #10
0
// In future we may want to cache this transition.
Structure* Structure::freezeTransition(JSGlobalData& globalData, Structure* structure)
{
    Structure* transition = preventExtensionsTransition(globalData, structure);

    if (transition->propertyTable()) {
        PropertyTable::iterator iter = transition->propertyTable()->begin();
        PropertyTable::iterator end = transition->propertyTable()->end();
        if (iter != end)
            transition->m_hasReadOnlyOrGetterSetterPropertiesExcludingProto = true;
        for (; iter != end; ++iter)
            iter->attributes |= iter->attributes & Accessor ? DontDelete : (DontDelete | ReadOnly);
    }

    transition->checkOffsetConsistency();
    return transition;
}
Example #11
0
// In future we may want to cache this transition.
Structure* Structure::preventExtensionsTransition(VM& vm, Structure* structure)
{
    Structure* transition = create(vm, structure);

    // Don't set m_offset, as one can not transition to this.

    DeferGC deferGC(vm.heap);
    structure->materializePropertyMapIfNecessary(vm, deferGC);
    transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
    transition->m_offset = structure->m_offset;
    transition->setPreventExtensions(true);
    transition->pin();

    transition->checkOffsetConsistency();
    return transition;
}
Example #12
0
// In future we may want to cache this transition.
Structure* Structure::freezeTransition(VM& vm, Structure* structure)
{
    Structure* transition = preventExtensionsTransition(vm, structure);

    if (transition->propertyTable()) {
        PropertyTable::iterator iter = transition->propertyTable()->begin();
        PropertyTable::iterator end = transition->propertyTable()->end();
        if (iter != end)
            transition->setHasReadOnlyOrGetterSetterPropertiesExcludingProto(true);
        for (; iter != end; ++iter)
            iter->attributes |= iter->attributes & Accessor ? DontDelete : (DontDelete | ReadOnly);
    }

    ASSERT(transition->hasReadOnlyOrGetterSetterPropertiesExcludingProto() || !transition->classInfo()->hasStaticSetterOrReadonlyProperties());
    ASSERT(transition->hasGetterSetterProperties() || !transition->classInfo()->hasStaticSetterOrReadonlyProperties());
    transition->checkOffsetConsistency();
    return transition;
}
Example #13
0
Structure* Structure::addPropertyTransition(JSGlobalData& globalData, Structure* structure, PropertyName propertyName, unsigned attributes, JSCell* specificValue, PropertyOffset& offset)
{
    // If we have a specific function, we may have got to this point if there is
    // already a transition with the correct property name and attributes, but
    // specialized to a different function.  In this case we just want to give up
    // and despecialize the transition.
    // In this case we clear the value of specificFunction which will result
    // in us adding a non-specific transition, and any subsequent lookup in
    // Structure::addPropertyTransitionToExistingStructure will just use that.
    if (specificValue && structure->m_transitionTable.contains(propertyName.uid(), attributes))
        specificValue = 0;

    ASSERT(!structure->isDictionary());
    ASSERT(structure->isObject());
    ASSERT(!Structure::addPropertyTransitionToExistingStructure(structure, propertyName, attributes, specificValue, offset));
    
    if (structure->m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
        specificValue = 0;

    if (structure->transitionCount() > s_maxTransitionLength) {
        Structure* transition = toCacheableDictionaryTransition(globalData, structure);
        ASSERT(structure != transition);
        offset = transition->putSpecificValue(globalData, propertyName, attributes, specificValue);
        return transition;
    }
    
    Structure* transition = create(globalData, structure);

    transition->m_cachedPrototypeChain.setMayBeNull(globalData, transition, structure->m_cachedPrototypeChain.get());
    transition->setPreviousID(globalData, transition, structure);
    transition->m_nameInPrevious = propertyName.uid();
    transition->m_attributesInPrevious = attributes;
    transition->m_specificValueInPrevious.setMayBeNull(globalData, transition, specificValue);
    transition->propertyTable().set(globalData, transition, structure->takePropertyTableOrCloneIfPinned(globalData, transition));
    transition->m_offset = structure->m_offset;

    offset = transition->putSpecificValue(globalData, propertyName, attributes, specificValue);

    checkOffset(transition->m_offset, transition->inlineCapacity());
    structure->m_transitionTable.add(globalData, transition);
    transition->checkOffsetConsistency();
    structure->checkOffsetConsistency();
    return transition;
}
Example #14
0
Structure* Structure::despecifyFunctionTransition(JSGlobalData& globalData, Structure* structure, PropertyName replaceFunction)
{
    ASSERT(structure->m_specificFunctionThrashCount < maxSpecificFunctionThrashCount);
    Structure* transition = create(globalData, structure);

    ++transition->m_specificFunctionThrashCount;

    structure->materializePropertyMapIfNecessary(globalData);
    transition->propertyTable().set(globalData, transition, structure->copyPropertyTableForPinning(globalData, transition));
    transition->m_offset = structure->m_offset;
    transition->pin();

    if (transition->m_specificFunctionThrashCount == maxSpecificFunctionThrashCount)
        transition->despecifyAllFunctions(globalData);
    else {
        bool removed = transition->despecifyFunction(globalData, replaceFunction);
        ASSERT_UNUSED(removed, removed);
    }

    transition->checkOffsetConsistency();
    return transition;
}
Example #15
0
Structure* Structure::nonPropertyTransition(VM& vm, Structure* structure, NonPropertyTransition transitionKind)
{
    unsigned attributes = toAttributes(transitionKind);
    IndexingType indexingType = newIndexingType(structure->indexingTypeIncludingHistory(), transitionKind);
    
    if (JSGlobalObject* globalObject = structure->m_globalObject.get()) {
        if (globalObject->isOriginalArrayStructure(structure)) {
            Structure* result = globalObject->originalArrayStructureForIndexingType(indexingType);
            if (result->indexingTypeIncludingHistory() == indexingType) {
                structure->didTransitionFromThisStructure();
                return result;
            }
        }
    }
    
    Structure* existingTransition;
    if (!structure->isDictionary() && (existingTransition = structure->m_transitionTable.get(0, attributes))) {
        ASSERT(existingTransition->attributesInPrevious() == attributes);
        ASSERT(existingTransition->indexingTypeIncludingHistory() == indexingType);
        return existingTransition;
    }
    
    Structure* transition = create(vm, structure);
    transition->setAttributesInPrevious(attributes);
    transition->m_blob.setIndexingType(indexingType);
    transition->propertyTable().set(vm, transition, structure->takePropertyTableOrCloneIfPinned(vm));
    transition->m_offset = structure->m_offset;
    checkOffset(transition->m_offset, transition->inlineCapacity());
    
    if (structure->isDictionary())
        transition->pin();
    else {
        ConcurrentJITLocker locker(structure->m_lock);
        structure->m_transitionTable.add(vm, transition);
    }
    transition->checkOffsetConsistency();
    return transition;
}
Example #16
0
Structure* Structure::addNewPropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, unsigned attributes, PropertyOffset& offset, PutPropertySlot::Context context, DeferredStructureTransitionWatchpointFire* deferred)
{
    ASSERT(!structure->isDictionary());
    ASSERT(structure->isObject());
    ASSERT(!Structure::addPropertyTransitionToExistingStructure(structure, propertyName, attributes, offset));

    int maxTransitionLength;
    if (context == PutPropertySlot::PutById)
        maxTransitionLength = s_maxTransitionLengthForNonEvalPutById;
    else
        maxTransitionLength = s_maxTransitionLength;
    if (structure->transitionCount() > maxTransitionLength) {
        Structure* transition = toCacheableDictionaryTransition(vm, structure, deferred);
        ASSERT(structure != transition);
        offset = transition->add(vm, propertyName, attributes);
        return transition;
    }

    Structure* transition = create(vm, structure, deferred);

    transition->m_cachedPrototypeChain.setMayBeNull(vm, transition, structure->m_cachedPrototypeChain.get());
    transition->m_nameInPrevious = propertyName.uid();
    transition->setAttributesInPrevious(attributes);
    transition->propertyTable().set(vm, transition, structure->takePropertyTableOrCloneIfPinned(vm));
    transition->m_offset = structure->m_offset;
    transition->m_inferredTypeTable.setMayBeNull(vm, transition, structure->m_inferredTypeTable.get());

    offset = transition->add(vm, propertyName, attributes);

    checkOffset(transition->m_offset, transition->inlineCapacity());
    {
        ConcurrentJITLocker locker(structure->m_lock);
        structure->m_transitionTable.add(vm, transition);
    }
    transition->checkOffsetConsistency();
    structure->checkOffsetConsistency();
    return transition;
}
Example #17
0
Structure* Structure::nonPropertyTransition(VM& vm, Structure* structure, NonPropertyTransition transitionKind)
{
    unsigned attributes = toAttributes(transitionKind);
    IndexingType indexingType = newIndexingType(structure->indexingTypeIncludingHistory(), transitionKind);

    if (changesIndexingType(transitionKind)) {
        if (JSGlobalObject* globalObject = structure->m_globalObject.get()) {
            if (globalObject->isOriginalArrayStructure(structure)) {
                Structure* result = globalObject->originalArrayStructureForIndexingType(indexingType);
                if (result->indexingTypeIncludingHistory() == indexingType) {
                    structure->didTransitionFromThisStructure();
                    return result;
                }
            }
        }
    }

    Structure* existingTransition;
    if (!structure->isDictionary() && (existingTransition = structure->m_transitionTable.get(0, attributes))) {
        ASSERT(existingTransition->attributesInPrevious() == attributes);
        ASSERT(existingTransition->indexingTypeIncludingHistory() == indexingType);
        return existingTransition;
    }

    DeferGC deferGC(vm.heap);

    Structure* transition = create(vm, structure);
    transition->setAttributesInPrevious(attributes);
    transition->m_blob.setIndexingType(indexingType);

    if (preventsExtensions(transitionKind))
        transition->setDidPreventExtensions(true);

    if (setsDontDeleteOnAllProperties(transitionKind)
            || setsReadOnlyOnNonAccessorProperties(transitionKind)) {
        // We pin the property table on transitions that do wholesale editing of the property
        // table, since our logic for walking the property transition chain to rematerialize the
        // table doesn't know how to take into account such wholesale edits.

        structure->materializePropertyMapIfNecessary(vm, deferGC);
        transition->propertyTable().set(vm, transition, structure->copyPropertyTableForPinning(vm));
        transition->m_offset = structure->m_offset;
        transition->pinForCaching();

        if (transition->propertyTable()) {
            for (auto& entry : *transition->propertyTable().get()) {
                if (setsDontDeleteOnAllProperties(transitionKind))
                    entry.attributes |= DontDelete;
                if (setsReadOnlyOnNonAccessorProperties(transitionKind) && !(entry.attributes & Accessor))
                    entry.attributes |= ReadOnly;
            }
        }
    } else {
        transition->propertyTable().set(vm, transition, structure->takePropertyTableOrCloneIfPinned(vm));
        transition->m_offset = structure->m_offset;
        checkOffset(transition->m_offset, transition->inlineCapacity());
    }

    if (setsReadOnlyOnNonAccessorProperties(transitionKind)
            && transition->propertyTable()
            && !transition->propertyTable()->isEmpty())
        transition->setHasReadOnlyOrGetterSetterPropertiesExcludingProto(true);

    if (structure->isDictionary())
        transition->pin();
    else {
        ConcurrentJITLocker locker(structure->m_lock);
        structure->m_transitionTable.add(vm, transition);
    }

    transition->checkOffsetConsistency();
    return transition;
}