tree 5c48eb9004eaa55551081e02b8535b09abad3d65
parent 792ffb71a52fc4b6ff583c9b0b2024d6c4071d51
author fpizlo@apple.com <fpizlo@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1438643636 +0000
committer fpizlo@apple.com <fpizlo@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1438643636 +0000

DFG should have adaptive structure watchpoints
https://bugs.webkit.org/show_bug.cgi?id=146929

Reviewed by Geoffrey Garen.

Source/JavaScriptCore:

Before this change, if you wanted to efficiently validate whether an object has (or doesn't have) a
property, you'd check that the object still has the structure that you first saw the object have. We
optimized this a bit with transition watchpoints on the structure, which sometimes allowed us to
elide the structure check.

But this approach fails when that object frequently has new properties added to it. This would
change the structure and fire the transition watchpoint, so the code we emitted would be invalid and
we'd have to recompile either the IC or an entire code block.

This change introduces a new concept: an object property condition. This value describes some
condition involving a property on some object. There are four kinds: presence, absence,
absence-of-setter, and equivalence. For example, a presence condition says that we expect that the
object has some property at some offset with some attributes. This allows us to implement a new kind
of watchpoint, which knows about the object property condition that it's being used to enforce. If
the watchpoint fires because of a structure transition, the watchpoint may simply reinstall itself
on the new structure.

Object property conditions are used on the prototype chain of PutById transitions, GetById misses,
and prototype accesses. They are also used for any DFG accesses to object constants, including
global property accesses.

Mostly because of the effect on global property access, this is a 9% speed-up on Kraken. It's
neutral on most other things. It's a 68x speed-up on a microbenchmark that illustrates the prototype
chain situation. It's also a small speed-up on getter-richards.

* CMakeLists.txt:
* JavaScriptCore.vcxproj/JavaScriptCore.vcxproj:
* JavaScriptCore.xcodeproj/project.pbxproj:
* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::printGetByIdCacheStatus):
(JSC::CodeBlock::printPutByIdCacheStatus):
* bytecode/CodeBlockJettisoningWatchpoint.cpp:
(JSC::CodeBlockJettisoningWatchpoint::fireInternal):
* bytecode/ComplexGetStatus.cpp:
(JSC::ComplexGetStatus::computeFor):
* bytecode/ComplexGetStatus.h:
(JSC::ComplexGetStatus::ComplexGetStatus):
(JSC::ComplexGetStatus::takesSlowPath):
(JSC::ComplexGetStatus::kind):
(JSC::ComplexGetStatus::offset):
(JSC::ComplexGetStatus::conditionSet):
(JSC::ComplexGetStatus::attributes): Deleted.
(JSC::ComplexGetStatus::specificValue): Deleted.
(JSC::ComplexGetStatus::chain): Deleted.
* bytecode/ConstantStructureCheck.cpp: Removed.
* bytecode/ConstantStructureCheck.h: Removed.
* bytecode/GetByIdStatus.cpp:
(JSC::GetByIdStatus::computeForStubInfo):
* bytecode/GetByIdVariant.cpp:
(JSC::GetByIdVariant::GetByIdVariant):
(JSC::GetByIdVariant::~GetByIdVariant):
(JSC::GetByIdVariant::operator=):
(JSC::GetByIdVariant::attemptToMerge):
(JSC::GetByIdVariant::dumpInContext):
(JSC::GetByIdVariant::baseStructure): Deleted.
* bytecode/GetByIdVariant.h:
(JSC::GetByIdVariant::operator!):
(JSC::GetByIdVariant::structureSet):
(JSC::GetByIdVariant::conditionSet):
(JSC::GetByIdVariant::offset):
(JSC::GetByIdVariant::callLinkStatus):
(JSC::GetByIdVariant::constantChecks): Deleted.
(JSC::GetByIdVariant::alternateBase): Deleted.
* bytecode/ObjectPropertyCondition.cpp: Added.
(JSC::ObjectPropertyCondition::dumpInContext):
(JSC::ObjectPropertyCondition::dump):
(JSC::ObjectPropertyCondition::structureEnsuresValidityAssumingImpurePropertyWatchpoint):
(JSC::ObjectPropertyCondition::validityRequiresImpurePropertyWatchpoint):
(JSC::ObjectPropertyCondition::isStillValid):
(JSC::ObjectPropertyCondition::structureEnsuresValidity):
(JSC::ObjectPropertyCondition::isWatchableAssumingImpurePropertyWatchpoint):
(JSC::ObjectPropertyCondition::isWatchable):
(JSC::ObjectPropertyCondition::isStillLive):
(JSC::ObjectPropertyCondition::validateReferences):
(JSC::ObjectPropertyCondition::attemptToMakeEquivalenceWithoutBarrier):
* bytecode/ObjectPropertyCondition.h: Added.
(JSC::ObjectPropertyCondition::ObjectPropertyCondition):
(JSC::ObjectPropertyCondition::presenceWithoutBarrier):
(JSC::ObjectPropertyCondition::presence):
(JSC::ObjectPropertyCondition::absenceWithoutBarrier):
(JSC::ObjectPropertyCondition::absence):
(JSC::ObjectPropertyCondition::absenceOfSetterWithoutBarrier):
(JSC::ObjectPropertyCondition::absenceOfSetter):
(JSC::ObjectPropertyCondition::equivalenceWithoutBarrier):
(JSC::ObjectPropertyCondition::equivalence):
(JSC::ObjectPropertyCondition::operator!):
(JSC::ObjectPropertyCondition::object):
(JSC::ObjectPropertyCondition::condition):
(JSC::ObjectPropertyCondition::kind):
(JSC::ObjectPropertyCondition::uid):
(JSC::ObjectPropertyCondition::hasOffset):
(JSC::ObjectPropertyCondition::offset):
(JSC::ObjectPropertyCondition::hasAttributes):
(JSC::ObjectPropertyCondition::attributes):
(JSC::ObjectPropertyCondition::hasPrototype):
(JSC::ObjectPropertyCondition::prototype):
(JSC::ObjectPropertyCondition::hasRequiredValue):
(JSC::ObjectPropertyCondition::requiredValue):
(JSC::ObjectPropertyCondition::hash):
(JSC::ObjectPropertyCondition::operator==):
(JSC::ObjectPropertyCondition::isHashTableDeletedValue):
(JSC::ObjectPropertyCondition::isCompatibleWith):
(JSC::ObjectPropertyCondition::watchingRequiresStructureTransitionWatchpoint):
(JSC::ObjectPropertyCondition::watchingRequiresReplacementWatchpoint):
(JSC::ObjectPropertyCondition::isValidValueForPresence):
(JSC::ObjectPropertyConditionHash::hash):
(JSC::ObjectPropertyConditionHash::equal):
* bytecode/ObjectPropertyConditionSet.cpp: Added.
(JSC::ObjectPropertyConditionSet::forObject):
(JSC::ObjectPropertyConditionSet::forConditionKind):
(JSC::ObjectPropertyConditionSet::numberOfConditionsWithKind):
(JSC::ObjectPropertyConditionSet::hasOneSlotBaseCondition):
(JSC::ObjectPropertyConditionSet::slotBaseCondition):
(JSC::ObjectPropertyConditionSet::mergedWith):
(JSC::ObjectPropertyConditionSet::structuresEnsureValidity):
(JSC::ObjectPropertyConditionSet::structuresEnsureValidityAssumingImpurePropertyWatchpoint):
(JSC::ObjectPropertyConditionSet::needImpurePropertyWatchpoint):
(JSC::ObjectPropertyConditionSet::areStillLive):
(JSC::ObjectPropertyConditionSet::dumpInContext):
(JSC::ObjectPropertyConditionSet::dump):
(JSC::generateConditionsForPropertyMiss):
(JSC::generateConditionsForPropertySetterMiss):
(JSC::generateConditionsForPrototypePropertyHit):
(JSC::generateConditionsForPrototypePropertyHitCustom):
(JSC::generateConditionsForPropertySetterMissConcurrently):
* bytecode/ObjectPropertyConditionSet.h: Added.
(JSC::ObjectPropertyConditionSet::ObjectPropertyConditionSet):
(JSC::ObjectPropertyConditionSet::invalid):
(JSC::ObjectPropertyConditionSet::nonEmpty):
(JSC::ObjectPropertyConditionSet::isValid):
(JSC::ObjectPropertyConditionSet::isEmpty):
(JSC::ObjectPropertyConditionSet::begin):
(JSC::ObjectPropertyConditionSet::end):
(JSC::ObjectPropertyConditionSet::releaseRawPointer):
(JSC::ObjectPropertyConditionSet::adoptRawPointer):
(JSC::ObjectPropertyConditionSet::fromRawPointer):
(JSC::ObjectPropertyConditionSet::Data::Data):
* bytecode/PolymorphicGetByIdList.cpp:
(JSC::GetByIdAccess::GetByIdAccess):
(JSC::GetByIdAccess::~GetByIdAccess):
(JSC::GetByIdAccess::visitWeak):
* bytecode/PolymorphicGetByIdList.h:
(JSC::GetByIdAccess::GetByIdAccess):
(JSC::GetByIdAccess::structure):
(JSC::GetByIdAccess::conditionSet):
(JSC::GetByIdAccess::stubRoutine):
(JSC::GetByIdAccess::chain): Deleted.
(JSC::GetByIdAccess::chainCount): Deleted.
* bytecode/PolymorphicPutByIdList.cpp:
(JSC::PutByIdAccess::fromStructureStubInfo):
(JSC::PutByIdAccess::visitWeak):
* bytecode/PolymorphicPutByIdList.h:
(JSC::PutByIdAccess::PutByIdAccess):
(JSC::PutByIdAccess::transition):
(JSC::PutByIdAccess::setter):
(JSC::PutByIdAccess::newStructure):
(JSC::PutByIdAccess::conditionSet):
(JSC::PutByIdAccess::stubRoutine):
(JSC::PutByIdAccess::chain): Deleted.
(JSC::PutByIdAccess::chainCount): Deleted.
* bytecode/PropertyCondition.cpp: Added.
(JSC::PropertyCondition::dumpInContext):
(JSC::PropertyCondition::dump):
(JSC::PropertyCondition::isStillValidAssumingImpurePropertyWatchpoint):
(JSC::PropertyCondition::validityRequiresImpurePropertyWatchpoint):
(JSC::PropertyCondition::isStillValid):
(JSC::PropertyCondition::isWatchableWhenValid):
(JSC::PropertyCondition::isWatchableAssumingImpurePropertyWatchpoint):
(JSC::PropertyCondition::isWatchable):
(JSC::PropertyCondition::isStillLive):
(JSC::PropertyCondition::validateReferences):
(JSC::PropertyCondition::isValidValueForAttributes):
(JSC::PropertyCondition::isValidValueForPresence):
(JSC::PropertyCondition::attemptToMakeEquivalenceWithoutBarrier):
(WTF::printInternal):
* bytecode/PropertyCondition.h: Added.
(JSC::PropertyCondition::PropertyCondition):
(JSC::PropertyCondition::presenceWithoutBarrier):
(JSC::PropertyCondition::presence):
(JSC::PropertyCondition::absenceWithoutBarrier):
(JSC::PropertyCondition::absence):
(JSC::PropertyCondition::absenceOfSetterWithoutBarrier):
(JSC::PropertyCondition::absenceOfSetter):
(JSC::PropertyCondition::equivalenceWithoutBarrier):
(JSC::PropertyCondition::equivalence):
(JSC::PropertyCondition::operator!):
(JSC::PropertyCondition::kind):
(JSC::PropertyCondition::uid):
(JSC::PropertyCondition::hasOffset):
(JSC::PropertyCondition::offset):
(JSC::PropertyCondition::hasAttributes):
(JSC::PropertyCondition::attributes):
(JSC::PropertyCondition::hasPrototype):
(JSC::PropertyCondition::prototype):
(JSC::PropertyCondition::hasRequiredValue):
(JSC::PropertyCondition::requiredValue):
(JSC::PropertyCondition::hash):
(JSC::PropertyCondition::operator==):
(JSC::PropertyCondition::isHashTableDeletedValue):
(JSC::PropertyCondition::isCompatibleWith):
(JSC::PropertyCondition::watchingRequiresStructureTransitionWatchpoint):
(JSC::PropertyCondition::watchingRequiresReplacementWatchpoint):
(JSC::PropertyConditionHash::hash):
(JSC::PropertyConditionHash::equal):
* bytecode/PutByIdStatus.cpp:
(JSC::PutByIdStatus::computeFromLLInt):
(JSC::PutByIdStatus::computeFor):
(JSC::PutByIdStatus::computeForStubInfo):
* bytecode/PutByIdVariant.cpp:
(JSC::PutByIdVariant::operator=):
(JSC::PutByIdVariant::transition):
(JSC::PutByIdVariant::setter):
(JSC::PutByIdVariant::makesCalls):
(JSC::PutByIdVariant::attemptToMerge):
(JSC::PutByIdVariant::attemptToMergeTransitionWithReplace):
(JSC::PutByIdVariant::dumpInContext):
(JSC::PutByIdVariant::baseStructure): Deleted.
* bytecode/PutByIdVariant.h:
(JSC::PutByIdVariant::PutByIdVariant):
(JSC::PutByIdVariant::kind):
(JSC::PutByIdVariant::structure):
(JSC::PutByIdVariant::structureSet):
(JSC::PutByIdVariant::oldStructure):
(JSC::PutByIdVariant::conditionSet):
(JSC::PutByIdVariant::offset):
(JSC::PutByIdVariant::callLinkStatus):
(JSC::PutByIdVariant::constantChecks): Deleted.
(JSC::PutByIdVariant::alternateBase): Deleted.
* bytecode/StructureStubClearingWatchpoint.cpp:
(JSC::StructureStubClearingWatchpoint::~StructureStubClearingWatchpoint):
(JSC::StructureStubClearingWatchpoint::push):
(JSC::StructureStubClearingWatchpoint::fireInternal):
(JSC::WatchpointsOnStructureStubInfo::~WatchpointsOnStructureStubInfo):
(JSC::WatchpointsOnStructureStubInfo::addWatchpoint):
(JSC::WatchpointsOnStructureStubInfo::ensureReferenceAndAddWatchpoint):
* bytecode/StructureStubClearingWatchpoint.h:
(JSC::StructureStubClearingWatchpoint::StructureStubClearingWatchpoint):
(JSC::WatchpointsOnStructureStubInfo::codeBlock):
(JSC::WatchpointsOnStructureStubInfo::stubInfo):
* bytecode/StructureStubInfo.cpp:
(JSC::StructureStubInfo::deref):
(JSC::StructureStubInfo::visitWeakReferences):
* bytecode/StructureStubInfo.h:
(JSC::StructureStubInfo::initPutByIdTransition):
(JSC::StructureStubInfo::initPutByIdReplace):
(JSC::StructureStubInfo::setSeen):
(JSC::StructureStubInfo::addWatchpoint):
* dfg/DFGAbstractInterpreterInlines.h:
(JSC::DFG::AbstractInterpreter<AbstractStateType>::executeEffects):
* dfg/DFGAdaptiveInferredPropertyValueWatchpoint.cpp: Added.
(JSC::DFG::AdaptiveInferredPropertyValueWatchpoint::AdaptiveInferredPropertyValueWatchpoint):
(JSC::DFG::AdaptiveInferredPropertyValueWatchpoint::install):
(JSC::DFG::AdaptiveInferredPropertyValueWatchpoint::fire):
(JSC::DFG::AdaptiveInferredPropertyValueWatchpoint::StructureWatchpoint::fireInternal):
(JSC::DFG::AdaptiveInferredPropertyValueWatchpoint::PropertyWatchpoint::fireInternal):
* dfg/DFGAdaptiveInferredPropertyValueWatchpoint.h: Added.
(JSC::DFG::AdaptiveInferredPropertyValueWatchpoint::key):
(JSC::DFG::AdaptiveInferredPropertyValueWatchpoint::StructureWatchpoint::StructureWatchpoint):
(JSC::DFG::AdaptiveInferredPropertyValueWatchpoint::PropertyWatchpoint::PropertyWatchpoint):
* dfg/DFGAdaptiveStructureWatchpoint.cpp: Added.
(JSC::DFG::AdaptiveStructureWatchpoint::AdaptiveStructureWatchpoint):
(JSC::DFG::AdaptiveStructureWatchpoint::install):
(JSC::DFG::AdaptiveStructureWatchpoint::fireInternal):
* dfg/DFGAdaptiveStructureWatchpoint.h: Added.
(JSC::DFG::AdaptiveStructureWatchpoint::key):
* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::cellConstantWithStructureCheck):
(JSC::DFG::ByteCodeParser::handleConstantInternalFunction):
(JSC::DFG::ByteCodeParser::handleGetByOffset):
(JSC::DFG::ByteCodeParser::handlePutByOffset):
(JSC::DFG::ByteCodeParser::check):
(JSC::DFG::ByteCodeParser::promoteToConstant):
(JSC::DFG::ByteCodeParser::planLoad):
(JSC::DFG::ByteCodeParser::load):
(JSC::DFG::ByteCodeParser::presenceLike):
(JSC::DFG::ByteCodeParser::checkPresenceLike):
(JSC::DFG::ByteCodeParser::store):
(JSC::DFG::ByteCodeParser::handleGetById):
(JSC::DFG::ByteCodeParser::handlePutById):
(JSC::DFG::ByteCodeParser::parseBlock):
(JSC::DFG::ByteCodeParser::emitChecks): Deleted.
* dfg/DFGCommonData.cpp:
(JSC::DFG::CommonData::validateReferences):
* dfg/DFGCommonData.h:
* dfg/DFGConstantFoldingPhase.cpp:
(JSC::DFG::ConstantFoldingPhase::foldConstants):
(JSC::DFG::ConstantFoldingPhase::emitGetByOffset):
(JSC::DFG::ConstantFoldingPhase::addBaseCheck):
(JSC::DFG::ConstantFoldingPhase::addStructureTransitionCheck):
(JSC::DFG::ConstantFoldingPhase::addChecks): Deleted.
* dfg/DFGDesiredWatchpoints.cpp:
(JSC::DFG::ArrayBufferViewWatchpointAdaptor::add):
(JSC::DFG::InferredValueAdaptor::add):
(JSC::DFG::AdaptiveStructureWatchpointAdaptor::add):
(JSC::DFG::DesiredWatchpoints::DesiredWatchpoints):
(JSC::DFG::DesiredWatchpoints::addLazily):
(JSC::DFG::DesiredWatchpoints::consider):
(JSC::DFG::DesiredWatchpoints::reallyAdd):
(JSC::DFG::DesiredWatchpoints::areStillValid):
(JSC::DFG::DesiredWatchpoints::dumpInContext):
* dfg/DFGDesiredWatchpoints.h:
(JSC::DFG::SetPointerAdaptor::add):
(JSC::DFG::SetPointerAdaptor::hasBeenInvalidated):
(JSC::DFG::SetPointerAdaptor::dumpInContext):
(JSC::DFG::InferredValueAdaptor::hasBeenInvalidated):
(JSC::DFG::InferredValueAdaptor::dumpInContext):
(JSC::DFG::ArrayBufferViewWatchpointAdaptor::hasBeenInvalidated):
(JSC::DFG::ArrayBufferViewWatchpointAdaptor::dumpInContext):
(JSC::DFG::AdaptiveStructureWatchpointAdaptor::hasBeenInvalidated):
(JSC::DFG::AdaptiveStructureWatchpointAdaptor::dumpInContext):
(JSC::DFG::GenericDesiredWatchpoints::reallyAdd):
(JSC::DFG::GenericDesiredWatchpoints::isWatched):
(JSC::DFG::GenericDesiredWatchpoints::dumpInContext):
(JSC::DFG::DesiredWatchpoints::isWatched):
(JSC::DFG::GenericSetAdaptor::add): Deleted.
(JSC::DFG::GenericSetAdaptor::hasBeenInvalidated): Deleted.
* dfg/DFGDesiredWeakReferences.cpp:
(JSC::DFG::DesiredWeakReferences::addLazily):
(JSC::DFG::DesiredWeakReferences::contains):
* dfg/DFGDesiredWeakReferences.h:
* dfg/DFGGraph.cpp:
(JSC::DFG::Graph::dump):
(JSC::DFG::Graph::clearFlagsOnAllNodes):
(JSC::DFG::Graph::watchCondition):
(JSC::DFG::Graph::isSafeToLoad):
(JSC::DFG::Graph::livenessFor):
(JSC::DFG::Graph::tryGetConstantProperty):
(JSC::DFG::Graph::visitChildren):
* dfg/DFGGraph.h:
(JSC::DFG::Graph::identifiers):
(JSC::DFG::Graph::watchpoints):
* dfg/DFGMultiGetByOffsetData.cpp: Added.
(JSC::DFG::GetByOffsetMethod::dumpInContext):
(JSC::DFG::GetByOffsetMethod::dump):
(JSC::DFG::MultiGetByOffsetCase::dumpInContext):
(JSC::DFG::MultiGetByOffsetCase::dump):
(WTF::printInternal):
* dfg/DFGMultiGetByOffsetData.h: Added.
(JSC::DFG::GetByOffsetMethod::GetByOffsetMethod):
(JSC::DFG::GetByOffsetMethod::constant):
(JSC::DFG::GetByOffsetMethod::load):
(JSC::DFG::GetByOffsetMethod::loadFromPrototype):
(JSC::DFG::GetByOffsetMethod::operator!):
(JSC::DFG::GetByOffsetMethod::kind):
(JSC::DFG::GetByOffsetMethod::prototype):
(JSC::DFG::GetByOffsetMethod::offset):
(JSC::DFG::MultiGetByOffsetCase::MultiGetByOffsetCase):
(JSC::DFG::MultiGetByOffsetCase::set):
(JSC::DFG::MultiGetByOffsetCase::method):
* dfg/DFGNode.h:
* dfg/DFGSafeToExecute.h:
(JSC::DFG::safeToExecute):
* dfg/DFGStructureRegistrationPhase.cpp:
(JSC::DFG::StructureRegistrationPhase::run):
* ftl/FTLLowerDFGToLLVM.cpp:
(JSC::FTL::DFG::LowerDFGToLLVM::compileMultiGetByOffset):
* jit/Repatch.cpp:
(JSC::repatchByIdSelfAccess):
(JSC::checkObjectPropertyCondition):
(JSC::checkObjectPropertyConditions):
(JSC::replaceWithJump):
(JSC::generateByIdStub):
(JSC::actionForCell):
(JSC::tryBuildGetByIDList):
(JSC::emitPutReplaceStub):
(JSC::emitPutTransitionStub):
(JSC::tryCachePutByID):
(JSC::tryBuildPutByIdList):
(JSC::tryRepatchIn):
(JSC::addStructureTransitionCheck): Deleted.
(JSC::emitPutTransitionStubAndGetOldStructure): Deleted.
* runtime/IntendedStructureChain.cpp: Removed.
* runtime/IntendedStructureChain.h: Removed.
* runtime/JSCJSValue.h:
* runtime/JSObject.cpp:
(JSC::throwTypeError):
(JSC::JSObject::convertToDictionary):
(JSC::JSObject::shiftButterflyAfterFlattening):
* runtime/JSObject.h:
(JSC::JSObject::flattenDictionaryObject):
(JSC::JSObject::convertToDictionary): Deleted.
* runtime/Operations.h:
(JSC::normalizePrototypeChain):
(JSC::normalizePrototypeChainForChainAccess): Deleted.
(JSC::isPrototypeChainNormalized): Deleted.
* runtime/PropertySlot.h:
(JSC::PropertySlot::PropertySlot):
(JSC::PropertySlot::slotBase):
* runtime/Structure.cpp:
(JSC::Structure::addPropertyTransition):
(JSC::Structure::attributeChangeTransition):
(JSC::Structure::toDictionaryTransition):
(JSC::Structure::toCacheableDictionaryTransition):
(JSC::Structure::toUncacheableDictionaryTransition):
(JSC::Structure::ensurePropertyReplacementWatchpointSet):
(JSC::Structure::startWatchingPropertyForReplacements):
(JSC::Structure::didCachePropertyReplacement):
(JSC::Structure::dump):
* runtime/Structure.h:
* runtime/VM.h:
* tests/stress/fold-multi-get-by-offset-to-get-by-offset-without-folding-the-structure-check-new.js: Added.
(foo):
(bar):
(baz):
* tests/stress/multi-get-by-offset-self-or-proto.js: Added.
(foo):
* tests/stress/replacement-watchpoint-dictionary.js: Added.
(foo):
* tests/stress/replacement-watchpoint.js: Added.
(foo):
* tests/stress/undefined-access-dictionary-then-proto-change.js: Added.
(foo):
* tests/stress/undefined-access-then-proto-change.js: Added.
(foo):

LayoutTests:

* js/regress/global-object-access-with-mutating-structure-expected.txt: Added.
* js/regress/global-object-access-with-mutating-structure.html: Added.
* js/regress/prototype-access-with-mutating-prototype-expected.txt: Added.
* js/regress/prototype-access-with-mutating-prototype.html: Added.
* js/regress/script-tests/global-object-access-with-mutating-structure.js: Added.
(foo):
* js/regress/script-tests/prototype-access-with-mutating-prototype.js: Added.
(foo):
* js/regress/script-tests/undefined-property-access.js:
(foo):
(bar):
(baz):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@187780 268f45cc-cd09-0410-ab3c-d52691b4dbfc