Attachment 287714 Details for Bug 160989 – patch

[patch] patch

c-backup.diff (text/plain), 157.64 KB, created by Saam Barati on 2016-09-01 19:23:32 PDT

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Creator: Saam Barati

Created: 2016-09-01 19:23:32 PDT

Size: 157.64 KB

patch

obsolete

>Index: PerformanceTests/ChangeLog
>===================================================================
>--- PerformanceTests/ChangeLog	(revision 205331)
>+++ PerformanceTests/ChangeLog	(working copy)
>@@ -1,3 +1,12 @@
>+2016-09-01  Saam Barati  <sbarati@apple.com>
>+
>+        Make JSMap and JSSet faster
>+        https://bugs.webkit.org/show_bug.cgi?id=160989
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * ES6SampleBench/cli.js:
>+
> 2016-08-23  Saam Barati  <sbarati@apple.com>
> 
>         It should be easy to run ES6SampleBench from the jsc shell
>Index: PerformanceTests/ES6SampleBench/cli.js
>===================================================================
>--- PerformanceTests/ES6SampleBench/cli.js	(revision 205305)
>+++ PerformanceTests/ES6SampleBench/cli.js	(working copy)
>@@ -30,4 +30,4 @@ load("air_benchmark.js");
> load("basic_benchmark.js");
> load("glue.js");
> 
>-driver.start(10);
>+driver.start(4);
>Index: Source/JavaScriptCore/ChangeLog
>===================================================================
>--- Source/JavaScriptCore/ChangeLog	(revision 205305)
>+++ Source/JavaScriptCore/ChangeLog	(working copy)
>@@ -1,3 +1,300 @@
>+2016-09-01  Saam Barati  <sbarati@apple.com>
>+
>+        Make JSMap and JSSet faster
>+        https://bugs.webkit.org/show_bug.cgi?id=160989
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        This patch revamps how we implement Map and Set. It uses
>+        a new hash map implementation. The hash map uses linear
>+        probing and it uses Wang's 64 bit hash function for JSValues
>+        that aren't strings. Strings use StringImpl's hash function.
>+        The reason I wanted to roll our own HashTable is twofold:
>+        I didn't want to inline WTF::HashMap's implementation into our
>+        JIT, since that seems error prone and unmaintainable. Also, I wanted
>+        a different structure for hash map buckets where buckets also exist in
>+        a linked list.
>+
>+        The reason for making buckets part of a linked list is that iteration
>+        is now simple. Iteration works by just traversing a linked list.
>+        This design also allows for a simple implementation when doing iteration
>+        while the hash table is mutating. Whenever we remove a bucket from
>+        the hash table, it is removed from the list, meaning items in the
>+        list don't point to it. However, the removed bucket will still point
>+        to things that are either in the list, or have also been removed.
>+        e.g, from a removed bucket, you can always follow pointers until you
>+        either find an item in the list, or you find the tail of the list.
>+        This is a really nice property because it means that a Map or Set
>+        does not need to reason about the all the iterators that point
>+        into its list. Also, whenever we add items to the Map or Set, we
>+        hijack the tail as the new item, and make the new item point to a newly
>+        created tail. This means that any iterator that pointed to the "tail" now
>+        points to non-tail items. This makes the implementation of adding things
>+        to the Map/Set while iterating easy.
>+
>+        I also made Map.prototype.get, Map.prototype.has, and Set.prototype.has
>+        into intrinsics in the DFG. The IR can now reason about hash map
>+        operations and can even do CSE over Wang's hash function, hash map
>+        bucket lookups, hash map bucket loads, and testing if a key is in
>+        the hash table. This makes code patterns for Map like so, super fast
>+        in the FTL, since we will only be doing a single hash and hash bucket lookup:
>+
>+        ```
>+        function getKeyIfPresent(map, key) {
>+        	if (map.has(key))
>+        		return map.get(key);
>+        }
>+        ```
>+
>+        This patch is roughly an 8% speedup on ES6SampleBench.
>+
>+        * CMakeLists.txt:
>+        * JavaScriptCore.xcodeproj/project.pbxproj:
>+        * bytecode/SpeculatedType.cpp:
>+        (JSC::speculationFromClassInfo):
>+        * bytecode/SpeculatedType.h:
>+        * dfg/DFGAbstractInterpreterInlines.h:
>+        (JSC::DFG::AbstractInterpreter<AbstractStateType>::executeEffects):
>+        (JSC::DFG::AbstractInterpreter<AbstractStateType>::execute):
>+        * dfg/DFGByteCodeParser.cpp:
>+        (JSC::DFG::ByteCodeParser::handleIntrinsicCall):
>+        * dfg/DFGClobberize.h:
>+        (JSC::DFG::clobberize):
>+        * dfg/DFGDoesGC.cpp:
>+        (JSC::DFG::doesGC):
>+        * dfg/DFGEdge.h:
>+        (JSC::DFG::Edge::shift):
>+        (JSC::DFG::Edge::makeWord):
>+        * dfg/DFGFixupPhase.cpp:
>+        (JSC::DFG::FixupPhase::fixupNode):
>+        * dfg/DFGHeapLocation.cpp:
>+        (WTF::printInternal):
>+        * dfg/DFGHeapLocation.h:
>+        * dfg/DFGNode.h:
>+        (JSC::DFG::Node::hasHeapPrediction):
>+        * dfg/DFGNodeType.h:
>+        * dfg/DFGOperations.cpp:
>+        * dfg/DFGOperations.h:
>+        * dfg/DFGPredictionPropagationPhase.cpp:
>+        * dfg/DFGSafeToExecute.h:
>+        (JSC::DFG::SafeToExecuteEdge::operator()):
>+        (JSC::DFG::safeToExecute):
>+        * dfg/DFGSpeculativeJIT.cpp:
>+        (JSC::DFG::SpeculativeJIT::speculateMapObject):
>+        (JSC::DFG::SpeculativeJIT::speculateSetObject):
>+        (JSC::DFG::SpeculativeJIT::speculate):
>+        * dfg/DFGSpeculativeJIT.h:
>+        (JSC::DFG::SpeculativeJIT::callOperation):
>+        * dfg/DFGSpeculativeJIT32_64.cpp:
>+        (JSC::DFG::SpeculativeJIT::compile):
>+        * dfg/DFGSpeculativeJIT64.cpp:
>+        (JSC::DFG::SpeculativeJIT::compile):
>+        * dfg/DFGUseKind.cpp:
>+        (WTF::printInternal):
>+        * dfg/DFGUseKind.h:
>+        (JSC::DFG::typeFilterFor):
>+        (JSC::DFG::isCell):
>+        * ftl/FTLAbstractHeapRepository.h:
>+        * ftl/FTLCapabilities.cpp:
>+        (JSC::FTL::canCompile):
>+        * ftl/FTLLowerDFGToB3.cpp:
>+        (JSC::FTL::DFG::LowerDFGToB3::compileNode):
>+        (JSC::FTL::DFG::LowerDFGToB3::compileMapHash):
>+        (JSC::FTL::DFG::LowerDFGToB3::compileGetMapBucket):
>+        (JSC::FTL::DFG::LowerDFGToB3::compileLoadFromJSMapBucket):
>+        (JSC::FTL::DFG::LowerDFGToB3::compileIsNonEmptyMapBucket):
>+        (JSC::FTL::DFG::LowerDFGToB3::lowMapObject):
>+        (JSC::FTL::DFG::LowerDFGToB3::lowSetObject):
>+        (JSC::FTL::DFG::LowerDFGToB3::lowMapBucket):
>+        (JSC::FTL::DFG::LowerDFGToB3::speculate):
>+        (JSC::FTL::DFG::LowerDFGToB3::speculateMapObject):
>+        (JSC::FTL::DFG::LowerDFGToB3::speculateSetObject):
>+        (JSC::FTL::DFG::LowerDFGToB3::setMapBucket):
>+        (JSC::FTL::DFG::LowerDFGToB3::lowRegExpObject): Deleted.
>+        (JSC::FTL::DFG::LowerDFGToB3::lowStorage): Deleted.
>+        (JSC::FTL::DFG::LowerDFGToB3::speculateRegExpObject): Deleted.
>+        (JSC::FTL::DFG::LowerDFGToB3::setStorage): Deleted.
>+        * jit/AssemblyHelpers.cpp:
>+        (JSC::AssemblyHelpers::WangsInt64Hash):
>+        * jit/AssemblyHelpers.h:
>+        (JSC::AssemblyHelpers::emitAllocateDestructibleObject): Deleted.
>+        * jit/JITOperations.h:
>+        * parser/ModuleAnalyzer.cpp:
>+        (JSC::ModuleAnalyzer::ModuleAnalyzer):
>+        * runtime/HashMapImpl.cpp: Added.
>+        (JSC::HashMapBucket<Data>::visitChildren):
>+        (JSC::HashMapImpl<HashMapBucket>::visitChildren):
>+        (JSC::HashMapImpl<HashMapBucket>::copyBackingStore):
>+        * runtime/HashMapImpl.h: Added.
>+        (JSC::HashMapBucket::selectStructure):
>+        (JSC::HashMapBucket::createStructure):
>+        (JSC::HashMapBucket::create):
>+        (JSC::HashMapBucket::HashMapBucket):
>+        (JSC::HashMapBucket::setNext):
>+        (JSC::HashMapBucket::setPrev):
>+        (JSC::HashMapBucket::setKey):
>+        (JSC::HashMapBucket::setValue):
>+        (JSC::HashMapBucket::key):
>+        (JSC::HashMapBucket::value):
>+        (JSC::HashMapBucket::next):
>+        (JSC::HashMapBucket::prev):
>+        (JSC::HashMapBucket::deleted):
>+        (JSC::HashMapBucket::setDeleted):
>+        (JSC::HashMapBucket::offsetOfKey):
>+        (JSC::HashMapBucket::offsetOfValue):
>+        (JSC::HashMapBuffer::allocationSize):
>+        (JSC::HashMapBuffer::buffer):
>+        (JSC::HashMapBuffer::create):
>+        (JSC::areKeysEqual):
>+        (JSC::normalizeMapKey):
>+        (JSC::jsMapHash):
>+        (JSC::HashMapImpl::selectStructure):
>+        (JSC::HashMapImpl::createStructure):
>+        (JSC::HashMapImpl::create):
>+        (JSC::HashMapImpl::HashMapImpl):
>+        (JSC::HashMapImpl::buffer):
>+        (JSC::HashMapImpl::finishCreation):
>+        (JSC::HashMapImpl::emptyValue):
>+        (JSC::HashMapImpl::isEmpty):
>+        (JSC::HashMapImpl::deletedValue):
>+        (JSC::HashMapImpl::isDeleted):
>+        (JSC::HashMapImpl::findBucket):
>+        (JSC::HashMapImpl::get):
>+        (JSC::HashMapImpl::has):
>+        (JSC::HashMapImpl::add):
>+        (JSC::HashMapImpl::remove):
>+        (JSC::HashMapImpl::size):
>+        (JSC::HashMapImpl::clear):
>+        (JSC::HashMapImpl::bufferSizeInBytes):
>+        (JSC::HashMapImpl::offsetOfBuffer):
>+        (JSC::HashMapImpl::offsetOfCapacity):
>+        (JSC::HashMapImpl::head):
>+        (JSC::HashMapImpl::tail):
>+        (JSC::HashMapImpl::approximateSize):
>+        (JSC::HashMapImpl::findBucketAlreadyHashedAndNormalized):
>+        (JSC::HashMapImpl::rehash):
>+        (JSC::HashMapImpl::makeAndSetNewBuffer):
>+        * runtime/Intrinsic.h:
>+        * runtime/JSCJSValue.h:
>+        * runtime/JSCJSValueInlines.h:
>+        (JSC::sameValue):
>+        * runtime/JSGlobalObject.cpp:
>+        (JSC::JSGlobalObject::init):
>+        * runtime/JSMap.cpp:
>+        (JSC::JSMap::destroy): Deleted.
>+        (JSC::JSMap::estimatedSize): Deleted.
>+        (JSC::JSMap::visitChildren): Deleted.
>+        (JSC::JSMap::copyBackingStore): Deleted.
>+        (JSC::JSMap::has): Deleted.
>+        (JSC::JSMap::size): Deleted.
>+        (JSC::JSMap::get): Deleted.
>+        (JSC::JSMap::set): Deleted.
>+        (JSC::JSMap::clear): Deleted.
>+        (JSC::JSMap::remove): Deleted.
>+        * runtime/JSMap.h:
>+        (JSC::JSMap::createStructure):
>+        (JSC::JSMap::create):
>+        (JSC::JSMap::get):
>+        (JSC::JSMap::set):
>+        (JSC::JSMap::JSMap):
>+        (JSC::JSMap::Entry::key): Deleted.
>+        (JSC::JSMap::Entry::value): Deleted.
>+        (JSC::JSMap::Entry::visitChildren): Deleted.
>+        (JSC::JSMap::Entry::setKey): Deleted.
>+        (JSC::JSMap::Entry::setKeyWithoutWriteBarrier): Deleted.
>+        (JSC::JSMap::Entry::setValue): Deleted.
>+        (JSC::JSMap::Entry::clear): Deleted.
>+        * runtime/JSMapIterator.cpp:
>+        (JSC::JSMapIterator::finishCreation):
>+        (JSC::JSMapIterator::visitChildren):
>+        (JSC::JSMapIterator::clone):
>+        * runtime/JSMapIterator.h:
>+        (JSC::JSMapIterator::advanceIter):
>+        (JSC::JSMapIterator::next):
>+        (JSC::JSMapIterator::nextKeyValue):
>+        (JSC::JSMapIterator::JSMapIterator):
>+        (JSC::JSMapIterator::setIterator):
>+        (JSC::JSMapIterator::finish): Deleted.
>+        (JSC::JSMapIterator::iteratorData): Deleted.
>+        * runtime/JSModuleLoader.cpp:
>+        (JSC::JSModuleLoader::finishCreation):
>+        * runtime/JSModuleLoader.h:
>+        (JSC::JSModuleLoader::create):
>+        * runtime/JSModuleRecord.cpp:
>+        (JSC::JSModuleRecord::finishCreation):
>+        * runtime/JSModuleRecord.h:
>+        (JSC::JSModuleRecord::create):
>+        * runtime/JSSet.cpp:
>+        (JSC::JSSet::destroy): Deleted.
>+        (JSC::JSSet::estimatedSize): Deleted.
>+        (JSC::JSSet::visitChildren): Deleted.
>+        (JSC::JSSet::copyBackingStore): Deleted.
>+        (JSC::JSSet::has): Deleted.
>+        (JSC::JSSet::size): Deleted.
>+        (JSC::JSSet::add): Deleted.
>+        (JSC::JSSet::clear): Deleted.
>+        (JSC::JSSet::remove): Deleted.
>+        * runtime/JSSet.h:
>+        (JSC::JSSet::createStructure):
>+        (JSC::JSSet::create):
>+        (JSC::JSSet::add):
>+        (JSC::JSSet::JSSet):
>+        (JSC::JSSet::Entry::key): Deleted.
>+        (JSC::JSSet::Entry::value): Deleted.
>+        (JSC::JSSet::Entry::visitChildren): Deleted.
>+        (JSC::JSSet::Entry::setKey): Deleted.
>+        (JSC::JSSet::Entry::setKeyWithoutWriteBarrier): Deleted.
>+        (JSC::JSSet::Entry::setValue): Deleted.
>+        (JSC::JSSet::Entry::clear): Deleted.
>+        * runtime/JSSetIterator.cpp:
>+        (JSC::JSSetIterator::finishCreation):
>+        (JSC::JSSetIterator::visitChildren):
>+        (JSC::JSSetIterator::clone):
>+        * runtime/JSSetIterator.h:
>+        (JSC::JSSetIterator::advanceIter):
>+        (JSC::JSSetIterator::next):
>+        (JSC::JSSetIterator::JSSetIterator):
>+        (JSC::JSSetIterator::setIterator):
>+        (JSC::JSSetIterator::finish): Deleted.
>+        (JSC::JSSetIterator::iteratorData): Deleted.
>+        * runtime/JSType.h:
>+        * runtime/MapBase.cpp: Added.
>+        (JSC::MapBase<HashMapBucketType>::visitChildren):
>+        (JSC::MapBase<HashMapBucketType>::estimatedSize):
>+        * runtime/MapBase.h: Added.
>+        (JSC::MapBase::size):
>+        (JSC::MapBase::has):
>+        (JSC::MapBase::clear):
>+        (JSC::MapBase::remove):
>+        (JSC::MapBase::findBucket):
>+        (JSC::MapBase::offsetOfHashMapImpl):
>+        (JSC::MapBase::impl):
>+        (JSC::MapBase::finishCreation):
>+        (JSC::MapBase::MapBase):
>+        * runtime/MapConstructor.cpp:
>+        (JSC::constructMap):
>+        * runtime/MapIteratorPrototype.cpp:
>+        (JSC::MapIteratorPrototypeFuncNext):
>+        * runtime/MapPrototype.cpp:
>+        (JSC::MapPrototype::finishCreation):
>+        (JSC::getMap):
>+        (JSC::privateFuncIsMap):
>+        (JSC::privateFuncMapIteratorNext):
>+        * runtime/PropertyDescriptor.cpp:
>+        (JSC::sameValue): Deleted.
>+        * runtime/PropertyDescriptor.h:
>+        * runtime/SetConstructor.cpp:
>+        (JSC::constructSet):
>+        * runtime/SetIteratorPrototype.cpp:
>+        (JSC::SetIteratorPrototypeFuncNext):
>+        * runtime/SetPrototype.cpp:
>+        (JSC::SetPrototype::finishCreation):
>+        (JSC::getSet):
>+        (JSC::privateFuncSetIteratorNext):
>+        * runtime/VM.cpp:
>+        (JSC::VM::VM):
>+        * runtime/VM.h:
>+
> 2016-09-01  Filip Pizlo  <fpizlo@apple.com>
> 
>         ObjectAllocationSinkingPhase::insertOSRHintsForUpdate() fails to emit updated hints in some cases
>Index: Source/JavaScriptCore/CMakeLists.txt
>===================================================================
>--- Source/JavaScriptCore/CMakeLists.txt	(revision 205305)
>+++ Source/JavaScriptCore/CMakeLists.txt	(working copy)
>@@ -667,6 +667,7 @@ set(JavaScriptCore_SOURCES
>     runtime/GeneratorFunctionPrototype.cpp
>     runtime/GeneratorPrototype.cpp
>     runtime/GetterSetter.cpp
>+    runtime/HashMapImpl.cpp
>     runtime/Identifier.cpp
>     runtime/IndexingType.cpp
>     runtime/InferredType.cpp
>@@ -752,6 +753,7 @@ set(JavaScriptCore_SOURCES
>     runtime/LazyClassStructure.cpp
>     runtime/LiteralParser.cpp
>     runtime/Lookup.cpp
>+    runtime/MapBase.cpp
>     runtime/MapConstructor.cpp
>     runtime/MapIteratorPrototype.cpp
>     runtime/MapPrototype.cpp
>Index: Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj
>===================================================================
>--- Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj	(revision 205305)
>+++ Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj	(working copy)
>@@ -1300,10 +1300,14 @@
> 		79233C2B1D34715700C5A834 /* JITMathIC.h in Headers */ = {isa = PBXBuildFile; fileRef = 79233C291D34715700C5A834 /* JITMathIC.h */; settings = {ATTRIBUTES = (Private, ); }; };
> 		792CB3491C4EED5C00D13AF3 /* PCToCodeOriginMap.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 792CB3471C4EED5C00D13AF3 /* PCToCodeOriginMap.cpp */; };
> 		792CB34A1C4EED5C00D13AF3 /* PCToCodeOriginMap.h in Headers */ = {isa = PBXBuildFile; fileRef = 792CB3481C4EED5C00D13AF3 /* PCToCodeOriginMap.h */; settings = {ATTRIBUTES = (Private, ); }; };
>+		795B19971D78BE3500262FA0 /* MapBase.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 795B19951D78BE3500262FA0 /* MapBase.cpp */; };
>+		795B19981D78BE3500262FA0 /* MapBase.h in Headers */ = {isa = PBXBuildFile; fileRef = 795B19961D78BE3500262FA0 /* MapBase.h */; settings = {ATTRIBUTES = (Private, ); }; };
> 		7964656A1B952FF0003059EE /* GetPutInfo.h in Headers */ = {isa = PBXBuildFile; fileRef = 796465681B952FF0003059EE /* GetPutInfo.h */; settings = {ATTRIBUTES = (Private, ); }; };
> 		797E07A91B8FCFB9008400BA /* JSGlobalLexicalEnvironment.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 797E07A71B8FCFB9008400BA /* JSGlobalLexicalEnvironment.cpp */; };
> 		797E07AA1B8FCFB9008400BA /* JSGlobalLexicalEnvironment.h in Headers */ = {isa = PBXBuildFile; fileRef = 797E07A81B8FCFB9008400BA /* JSGlobalLexicalEnvironment.h */; settings = {ATTRIBUTES = (Private, ); }; };
> 		799EF7C41C56ED96002B0534 /* B3PCToOriginMap.h in Headers */ = {isa = PBXBuildFile; fileRef = 799EF7C31C56ED96002B0534 /* B3PCToOriginMap.h */; settings = {ATTRIBUTES = (Private, ); }; };
>+		79A0907F1D768465008B889B /* HashMapImpl.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 79A0907D1D768465008B889B /* HashMapImpl.cpp */; };
>+		79A090801D768465008B889B /* HashMapImpl.h in Headers */ = {isa = PBXBuildFile; fileRef = 79A0907E1D768465008B889B /* HashMapImpl.h */; settings = {ATTRIBUTES = (Private, ); }; };
> 		79A228351D35D71E00D8E067 /* ArithProfile.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 79A228331D35D71E00D8E067 /* ArithProfile.cpp */; };
> 		79A228361D35D71F00D8E067 /* ArithProfile.h in Headers */ = {isa = PBXBuildFile; fileRef = 79A228341D35D71E00D8E067 /* ArithProfile.h */; };
> 		79AF0BE41D3EFD4C00E95FA5 /* JITMathICInlineResult.h in Headers */ = {isa = PBXBuildFile; fileRef = 79AF0BE31D3EFD4C00E95FA5 /* JITMathICInlineResult.h */; settings = {ATTRIBUTES = (Private, ); }; };
>@@ -3533,10 +3537,14 @@
> 		79233C291D34715700C5A834 /* JITMathIC.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = JITMathIC.h; sourceTree = "<group>"; };
> 		792CB3471C4EED5C00D13AF3 /* PCToCodeOriginMap.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = PCToCodeOriginMap.cpp; sourceTree = "<group>"; };
> 		792CB3481C4EED5C00D13AF3 /* PCToCodeOriginMap.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = PCToCodeOriginMap.h; sourceTree = "<group>"; };
>+		795B19951D78BE3500262FA0 /* MapBase.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = MapBase.cpp; sourceTree = "<group>"; };
>+		795B19961D78BE3500262FA0 /* MapBase.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MapBase.h; sourceTree = "<group>"; };
> 		796465681B952FF0003059EE /* GetPutInfo.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = GetPutInfo.h; sourceTree = "<group>"; };
> 		797E07A71B8FCFB9008400BA /* JSGlobalLexicalEnvironment.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = JSGlobalLexicalEnvironment.cpp; sourceTree = "<group>"; };
> 		797E07A81B8FCFB9008400BA /* JSGlobalLexicalEnvironment.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = JSGlobalLexicalEnvironment.h; sourceTree = "<group>"; };
> 		799EF7C31C56ED96002B0534 /* B3PCToOriginMap.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = B3PCToOriginMap.h; path = b3/B3PCToOriginMap.h; sourceTree = "<group>"; };
>+		79A0907D1D768465008B889B /* HashMapImpl.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = HashMapImpl.cpp; sourceTree = "<group>"; };
>+		79A0907E1D768465008B889B /* HashMapImpl.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = HashMapImpl.h; sourceTree = "<group>"; };
> 		79A228331D35D71E00D8E067 /* ArithProfile.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = ArithProfile.cpp; sourceTree = "<group>"; };
> 		79A228341D35D71E00D8E067 /* ArithProfile.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ArithProfile.h; sourceTree = "<group>"; };
> 		79A899FE1D38612E00D18C73 /* JITMathICForwards.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = JITMathICForwards.h; sourceTree = "<group>"; };
>@@ -5774,6 +5782,8 @@
> 				796465681B952FF0003059EE /* GetPutInfo.h */,
> 				BC02E9B80E184545000F9297 /* GetterSetter.cpp */,
> 				BC337BDE0E1AF0B80076918A /* GetterSetter.h */,
>+				79A0907D1D768465008B889B /* HashMapImpl.cpp */,
>+				79A0907E1D768465008B889B /* HashMapImpl.h */,
> 				933A349D038AE80F008635CE /* Identifier.cpp */,
> 				933A349A038AE7C6008635CE /* Identifier.h */,
> 				8606DDE918DA44AB00A383D0 /* IdentifierInlines.h */,
>@@ -5982,6 +5992,8 @@
> 				A7E2EA690FB460CF00601F06 /* LiteralParser.h */,
> 				F692A8680255597D01FF60F7 /* Lookup.cpp */,
> 				F692A8690255597D01FF60F7 /* Lookup.h */,
>+				795B19951D78BE3500262FA0 /* MapBase.cpp */,
>+				795B19961D78BE3500262FA0 /* MapBase.h */,
> 				A700873717CBE85300C3E643 /* MapConstructor.cpp */,
> 				A700873817CBE85300C3E643 /* MapConstructor.h */,
> 				A78507D517CBC6FD0011F6E7 /* MapData.h */,
>@@ -7271,6 +7283,7 @@
> 				0F64B27A1A7957B2006E4E66 /* CallEdge.h in Headers */,
> 				1429D8DE0ED2205B00B89619 /* CallFrame.h in Headers */,
> 				62EC9BB71B7EB07C00303AD1 /* CallFrameShuffleData.h in Headers */,
>+				795B19981D78BE3500262FA0 /* MapBase.h in Headers */,
> 				62D755D71B84FB4A001801FA /* CallFrameShuffler.h in Headers */,
> 				0F0B83B114BCF71800885B4F /* CallLinkInfo.h in Headers */,
> 				0F93329E14CA7DC50085F3C6 /* CallLinkStatus.h in Headers */,
>@@ -7437,6 +7450,7 @@
> 				0F9D339717FFC4E60073C2BC /* DFGFlushedAt.h in Headers */,
> 				A7D89CF817A0B8CC00773AD8 /* DFGFlushFormat.h in Headers */,
> 				0F2DD8151AB3D8BE00BBB8E8 /* DFGForAllKills.h in Headers */,
>+				79A090801D768465008B889B /* HashMapImpl.h in Headers */,
> 				0F69CC89193AC60A0045759E /* DFGFrozenValue.h in Headers */,
> 				86EC9DC61328DF82002B2AD7 /* DFGGenerationInfo.h in Headers */,
> 				86EC9DC81328DF82002B2AD7 /* DFGGraph.h in Headers */,
>@@ -9157,6 +9171,7 @@
> 				0F0332C018ADFAE1005F979A /* ExitingJITType.cpp in Sources */,
> 				0FB105851675480F00F8AB6E /* ExitKind.cpp in Sources */,
> 				0FEA0A1C1708B00700BB722C /* FTLAbstractHeap.cpp in Sources */,
>+				79A0907F1D768465008B889B /* HashMapImpl.cpp in Sources */,
> 				0FEA0A1E1708B00700BB722C /* FTLAbstractHeapRepository.cpp in Sources */,
> 				0F93274D1C1F66AA00CF6564 /* GPRInfo.cpp in Sources */,
> 				0F485327187DFDEC0083B687 /* FTLAvailableRecovery.cpp in Sources */,
>@@ -9201,6 +9216,7 @@
> 				52B310FD1974AE870080857C /* FunctionHasExecutedCache.cpp in Sources */,
> 				FE4BFF2B1AD476E700088F87 /* FunctionOverrides.cpp in Sources */,
> 				147F39CC107EC37600427A48 /* FunctionPrototype.cpp in Sources */,
>+				795B19971D78BE3500262FA0 /* MapBase.cpp in Sources */,
> 				62D2D38F1ADF103F000206C1 /* FunctionRareData.cpp in Sources */,
> 				2AACE63C18CA5A0300ED0191 /* GCActivityCallback.cpp in Sources */,
> 				0F766D2F15A8DCE0008F363E /* GCAwareJITStubRoutine.cpp in Sources */,
>Index: Source/JavaScriptCore/bytecode/SpeculatedType.cpp
>===================================================================
>--- Source/JavaScriptCore/bytecode/SpeculatedType.cpp	(revision 205305)
>+++ Source/JavaScriptCore/bytecode/SpeculatedType.cpp	(working copy)
>@@ -30,9 +30,11 @@
> #include "SpeculatedType.h"
> 
> #include "DirectArguments.h"
>+#include "JSCInlines.h"
> #include "JSArray.h"
> #include "JSFunction.h"
>-#include "JSCInlines.h"
>+#include "JSMap.h"
>+#include "JSSet.h"
> #include "ScopedArguments.h"
> #include "StringObject.h"
> #include "ValueProfile.h"
>@@ -346,6 +348,12 @@ SpeculatedType speculationFromClassInfo(
> 
>     if (classInfo == RegExpObject::info())
>         return SpecRegExpObject;
>+
>+    if (classInfo == JSMap::info())
>+        return SpecMapObject;
>+
>+    if (classInfo == JSSet::info())
>+        return SpecSetObject;
>     
>     if (classInfo->isSubClassOf(JSFunction::info()))
>         return SpecFunction;
>Index: Source/JavaScriptCore/bytecode/SpeculatedType.h
>===================================================================
>--- Source/JavaScriptCore/bytecode/SpeculatedType.h	(revision 205305)
>+++ Source/JavaScriptCore/bytecode/SpeculatedType.h	(working copy)
>@@ -39,41 +39,43 @@ class Structure;
> 
> typedef uint64_t SpeculatedType;
> static const SpeculatedType SpecNone               = 0; // We don't know anything yet.
>-static const SpeculatedType SpecFinalObject        = 1u << 0; // It's definitely a JSFinalObject.
>-static const SpeculatedType SpecArray              = 1u << 1; // It's definitely a JSArray.
>-static const SpeculatedType SpecFunction           = 1u << 2; // It's definitely a JSFunction.
>-static const SpeculatedType SpecInt8Array          = 1u << 3; // It's definitely an Int8Array or one of its subclasses.
>-static const SpeculatedType SpecInt16Array         = 1u << 4; // It's definitely an Int16Array or one of its subclasses.
>-static const SpeculatedType SpecInt32Array         = 1u << 5; // It's definitely an Int32Array or one of its subclasses.
>-static const SpeculatedType SpecUint8Array         = 1u << 6; // It's definitely an Uint8Array or one of its subclasses.
>-static const SpeculatedType SpecUint8ClampedArray  = 1u << 7; // It's definitely an Uint8ClampedArray or one of its subclasses.
>-static const SpeculatedType SpecUint16Array        = 1u << 8; // It's definitely an Uint16Array or one of its subclasses.
>-static const SpeculatedType SpecUint32Array        = 1u << 9; // It's definitely an Uint32Array or one of its subclasses.
>-static const SpeculatedType SpecFloat32Array       = 1u << 10; // It's definitely an Uint16Array or one of its subclasses.
>-static const SpeculatedType SpecFloat64Array       = 1u << 11; // It's definitely an Uint16Array or one of its subclasses.
>+static const SpeculatedType SpecFinalObject        = 1ull << 0; // It's definitely a JSFinalObject.
>+static const SpeculatedType SpecArray              = 1ull << 1; // It's definitely a JSArray.
>+static const SpeculatedType SpecFunction           = 1ull << 2; // It's definitely a JSFunction.
>+static const SpeculatedType SpecInt8Array          = 1ull << 3; // It's definitely an Int8Array or one of its subclasses.
>+static const SpeculatedType SpecInt16Array         = 1ull << 4; // It's definitely an Int16Array or one of its subclasses.
>+static const SpeculatedType SpecInt32Array         = 1ull << 5; // It's definitely an Int32Array or one of its subclasses.
>+static const SpeculatedType SpecUint8Array         = 1ull << 6; // It's definitely an Uint8Array or one of its subclasses.
>+static const SpeculatedType SpecUint8ClampedArray  = 1ull << 7; // It's definitely an Uint8ClampedArray or one of its subclasses.
>+static const SpeculatedType SpecUint16Array        = 1ull << 8; // It's definitely an Uint16Array or one of its subclasses.
>+static const SpeculatedType SpecUint32Array        = 1ull << 9; // It's definitely an Uint32Array or one of its subclasses.
>+static const SpeculatedType SpecFloat32Array       = 1ull << 10; // It's definitely an Uint16Array or one of its subclasses.
>+static const SpeculatedType SpecFloat64Array       = 1ull << 11; // It's definitely an Uint16Array or one of its subclasses.
> static const SpeculatedType SpecTypedArrayView     = SpecInt8Array | SpecInt16Array | SpecInt32Array | SpecUint8Array | SpecUint8ClampedArray | SpecUint16Array | SpecUint32Array | SpecFloat32Array | SpecFloat64Array;
>-static const SpeculatedType SpecDirectArguments    = 1u << 12; // It's definitely a DirectArguments object.
>-static const SpeculatedType SpecScopedArguments    = 1u << 13; // It's definitely a ScopedArguments object.
>-static const SpeculatedType SpecStringObject       = 1u << 14; // It's definitely a StringObject.
>-static const SpeculatedType SpecRegExpObject       = 1u << 15; // It's definitely a RegExpObject (and not any subclass of RegExpObject).
>-static const SpeculatedType SpecObjectOther        = 1u << 16; // It's definitely an object but not JSFinalObject, JSArray, or JSFunction.
>-static const SpeculatedType SpecObject             = SpecFinalObject | SpecArray | SpecFunction | SpecTypedArrayView | SpecDirectArguments | SpecScopedArguments | SpecStringObject | SpecRegExpObject | SpecObjectOther; // Bitmask used for testing for any kind of object prediction.
>-static const SpeculatedType SpecStringIdent        = 1u << 17; // It's definitely a JSString, and it's an identifier.
>-static const SpeculatedType SpecStringVar          = 1u << 18; // It's definitely a JSString, and it's not an identifier.
>+static const SpeculatedType SpecDirectArguments    = 1ull << 12; // It's definitely a DirectArguments object.
>+static const SpeculatedType SpecScopedArguments    = 1ull << 13; // It's definitely a ScopedArguments object.
>+static const SpeculatedType SpecStringObject       = 1ull << 14; // It's definitely a StringObject.
>+static const SpeculatedType SpecRegExpObject       = 1ull << 15; // It's definitely a RegExpObject (and not any subclass of RegExpObject).
>+static const SpeculatedType SpecMapObject          = 1ull << 16; // It's definitely Map object (can it be a subclass? FIXME).
>+static const SpeculatedType SpecSetObject          = 1ull << 17; // It's definitely s Set object (can it be a subclass? FIXME).
>+static const SpeculatedType SpecObjectOther        = 1ull << 18; // It's definitely an object but not JSFinalObject, JSArray, or JSFunction.
>+static const SpeculatedType SpecObject             = SpecFinalObject | SpecArray | SpecFunction | SpecTypedArrayView | SpecDirectArguments | SpecScopedArguments | SpecStringObject | SpecRegExpObject | SpecMapObject | SpecSetObject | SpecObjectOther; // Bitmask used for testing for any kind of object prediction.
>+static const SpeculatedType SpecStringIdent        = 1ull << 19; // It's definitely a JSString, and it's an identifier.
>+static const SpeculatedType SpecStringVar          = 1ull << 20; // It's definitely a JSString, and it's not an identifier.
> static const SpeculatedType SpecString             = SpecStringIdent | SpecStringVar; // It's definitely a JSString.
>-static const SpeculatedType SpecSymbol             = 1u << 19; // It's definitely a Symbol.
>-static const SpeculatedType SpecCellOther          = 1u << 20; // It's definitely a JSCell but not a subclass of JSObject and definitely not a JSString or a Symbol. FIXME: This shouldn't be part of heap-top or bytecode-top. https://bugs.webkit.org/show_bug.cgi?id=133078
>+static const SpeculatedType SpecSymbol             = 1ull << 21; // It's definitely a Symbol.
>+static const SpeculatedType SpecCellOther          = 1ull << 22; // It's definitely a JSCell but not a subclass of JSObject and definitely not a JSString or a Symbol. FIXME: This shouldn't be part of heap-top or bytecode-top. https://bugs.webkit.org/show_bug.cgi?id=133078
> static const SpeculatedType SpecCell               = SpecObject | SpecString | SpecSymbol | SpecCellOther; // It's definitely a JSCell.
>-static const SpeculatedType SpecBoolInt32          = 1u << 21; // It's definitely an Int32 with value 0 or 1.
>-static const SpeculatedType SpecNonBoolInt32       = 1u << 22; // It's definitely an Int32 with value other than 0 or 1.
>+static const SpeculatedType SpecBoolInt32          = 1ull << 23; // It's definitely an Int32 with value 0 or 1.
>+static const SpeculatedType SpecNonBoolInt32       = 1ull << 24; // It's definitely an Int32 with value other than 0 or 1.
> static const SpeculatedType SpecInt32Only          = SpecBoolInt32 | SpecNonBoolInt32; // It's definitely an Int32.
>-static const SpeculatedType SpecInt52Only          = 1u << 23; // It's definitely an Int52 and we intend it to unbox it. It's also definitely not an Int32.
>+static const SpeculatedType SpecInt52Only          = 1ull << 25; // It's definitely an Int52 and we intend it to unbox it. It's also definitely not an Int32.
> static const SpeculatedType SpecAnyInt             = SpecInt32Only | SpecInt52Only; // It's something that we can do machine int arithmetic on.
>-static const SpeculatedType SpecAnyIntAsDouble     = 1u << 24; // It's definitely an Int52 and it's inside a double.
>-static const SpeculatedType SpecNonIntAsDouble     = 1u << 25; // It's definitely not an Int52 but it's a real number and it's a double.
>+static const SpeculatedType SpecAnyIntAsDouble     = 1ull << 26; // It's definitely an Int52 and it's inside a double.
>+static const SpeculatedType SpecNonIntAsDouble     = 1ull << 27; // It's definitely not an Int52 but it's a real number and it's a double.
> static const SpeculatedType SpecDoubleReal         = SpecNonIntAsDouble | SpecAnyIntAsDouble; // It's definitely a non-NaN double.
>-static const SpeculatedType SpecDoublePureNaN      = 1u << 26; // It's definitely a NaN that is sae to tag (i.e. pure).
>-static const SpeculatedType SpecDoubleImpureNaN    = 1u << 27; // It's definitely a NaN that is unsafe to tag (i.e. impure).
>+static const SpeculatedType SpecDoublePureNaN      = 1ull << 28; // It's definitely a NaN that is sae to tag (i.e. pure).
>+static const SpeculatedType SpecDoubleImpureNaN    = 1ull << 29; // It's definitely a NaN that is unsafe to tag (i.e. impure).
> static const SpeculatedType SpecDoubleNaN          = SpecDoublePureNaN | SpecDoubleImpureNaN; // It's definitely some kind of NaN.
> static const SpeculatedType SpecBytecodeDouble     = SpecDoubleReal | SpecDoublePureNaN; // It's either a non-NaN or a NaN double, but it's definitely not impure NaN.
> static const SpeculatedType SpecFullDouble         = SpecDoubleReal | SpecDoubleNaN; // It's either a non-NaN or a NaN double.
>@@ -81,12 +83,12 @@ static const SpeculatedType SpecBytecode
> static const SpeculatedType SpecFullRealNumber     = SpecAnyInt | SpecDoubleReal; // It's either an Int32 or a DoubleReal, or a Int52.
> static const SpeculatedType SpecBytecodeNumber     = SpecInt32Only | SpecBytecodeDouble; // It's either an Int32 or a Double, and the Double cannot be an impure NaN.
> static const SpeculatedType SpecFullNumber         = SpecAnyInt | SpecFullDouble; // It's either an Int32, Int52, or a Double, and the Double can be impure NaN.
>-static const SpeculatedType SpecBoolean            = 1u << 28; // It's definitely a Boolean.
>-static const SpeculatedType SpecOther              = 1u << 29; // It's definitely either Null or Undefined.
>+static const SpeculatedType SpecBoolean            = 1ull << 30; // It's definitely a Boolean.
>+static const SpeculatedType SpecOther              = 1ull << 31; // It's definitely either Null or Undefined.
> static const SpeculatedType SpecMisc               = SpecBoolean | SpecOther; // It's definitely either a boolean, Null, or Undefined.
> static const SpeculatedType SpecHeapTop            = SpecCell | SpecBytecodeNumber | SpecMisc; // It can be any of the above, except for SpecInt52Only and SpecDoubleImpureNaN.
> static const SpeculatedType SpecPrimitive          = SpecString | SpecSymbol | SpecBytecodeNumber | SpecMisc; // It's any non-Object JSValue.
>-static const SpeculatedType SpecEmpty              = 1u << 30; // It's definitely an empty value marker.
>+static const SpeculatedType SpecEmpty              = 1ull << 32; // It's definitely an empty value marker.
> static const SpeculatedType SpecBytecodeTop        = SpecHeapTop | SpecEmpty; // It can be any of the above, except for SpecInt52Only and SpecDoubleImpureNaN. Corresponds to what could be found in a bytecode local.
> static const SpeculatedType SpecFullTop            = SpecBytecodeTop | SpecFullNumber; // It can be anything that bytecode could see plus exotic encodings of numbers.
> 
>Index: Source/JavaScriptCore/dfg/DFGAbstractInterpreterInlines.h
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGAbstractInterpreterInlines.h	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGAbstractInterpreterInlines.h	(working copy)
>@@ -977,6 +977,22 @@ bool AbstractInterpreter<AbstractStateTy
>         break;
>     }
> 
>+    case MapHash:
>+        forNode(node).setType(SpecInt32Only);
>+        break;
>+
>+    case LoadFromJSMapBucket:
>+        forNode(node).makeHeapTop();
>+        break;
>+
>+    case GetMapBucket:
>+        forNode(node).setType(m_graph, SpecCellOther);
>+        break;
>+
>+    case IsNonEmptyMapBucket:
>+        forNode(node).setType(SpecBoolean);
>+        break;
>+
>     case IsEmpty:
>     case IsJSArray:
>     case IsUndefined:
>@@ -2883,7 +2899,7 @@ template<typename AbstractStateType>
> bool AbstractInterpreter<AbstractStateType>::execute(unsigned indexInBlock)
> {
>     Node* node = m_state.block()->at(indexInBlock);
>-    
>+
>     startExecuting();
>     executeEdges(node);
>     return executeEffects(indexInBlock, node);
>Index: Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp	(working copy)
>@@ -2538,7 +2538,37 @@ bool ByteCodeParser::handleIntrinsicCall
>             set(VirtualRegister(resultOperand), get(operand));
>         return true;
>     }
>-        
>+
>+    case JSMapGetIntrinsic: {
>+        if (argumentCountIncludingThis != 2)
>+            return false;
>+
>+        insertChecks();
>+        Node* map = get(virtualRegisterForArgument(0, registerOffset));
>+        Node* key = get(virtualRegisterForArgument(1, registerOffset));
>+        Node* hash = addToGraph(MapHash, key);
>+        Node* bucket = addToGraph(GetMapBucket, Edge(map, MapObjectUse), Edge(key), Edge(hash));
>+        Node* result = addToGraph(LoadFromJSMapBucket, OpInfo(), OpInfo(prediction), bucket);
>+        set(VirtualRegister(resultOperand), result);
>+        return true;
>+    }
>+
>+    case JSSetHasIntrinsic:
>+    case JSMapHasIntrinsic: {
>+        if (argumentCountIncludingThis != 2)
>+            return false;
>+
>+        insertChecks();
>+        Node* mapOrSet = get(virtualRegisterForArgument(0, registerOffset));
>+        Node* key = get(virtualRegisterForArgument(1, registerOffset));
>+        Node* hash = addToGraph(MapHash, key);
>+        UseKind useKind = intrinsic == JSSetHasIntrinsic ? SetObjectUse : MapObjectUse;
>+        Node* bucket = addToGraph(GetMapBucket, OpInfo(0), Edge(mapOrSet, useKind), Edge(key), Edge(hash));
>+        Node* result = addToGraph(IsNonEmptyMapBucket, bucket);
>+        set(VirtualRegister(resultOperand), result);
>+        return true;
>+    }
>+
>     default:
>         return false;
>     }
>Index: Source/JavaScriptCore/dfg/DFGClobberize.h
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGClobberize.h	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGClobberize.h	(working copy)
>@@ -1243,6 +1243,27 @@ void clobberize(Graph& graph, Node* node
>     case LogShadowChickenTail:
>         write(SideState);
>         return;
>+
>+    case MapHash:
>+        def(PureValue(node));
>+        return;
>+    case GetMapBucket: {
>+        read(MiscFields);
>+        Edge& mapEdge = node->child1();
>+        Edge& keyEdge = node->child2();
>+        def(HeapLocation(MapBucketLoc, MiscFields, mapEdge, keyEdge), LazyNode(node));
>+        return;
>+    }
>+    case LoadFromJSMapBucket: {
>+        read(MiscFields);
>+        Edge& bucketEdge = node->child1();
>+        def(HeapLocation(JSMapGetLoc, MiscFields, bucketEdge), LazyNode(node));
>+        return;
>+    }
>+    case IsNonEmptyMapBucket:
>+        read(MiscFields);
>+        def(HeapLocation(MapHasLoc, MiscFields, node->child1()), LazyNode(node));
>+        return;
>         
>     case LastNodeType:
>         RELEASE_ASSERT_NOT_REACHED();
>Index: Source/JavaScriptCore/dfg/DFGDoesGC.cpp
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGDoesGC.cpp	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGDoesGC.cpp	(working copy)
>@@ -185,6 +185,10 @@ bool doesGC(Graph& graph, Node* node)
>     case ForceOSRExit:
>     case CheckWatchdogTimer:
>     case StringFromCharCode:
>+    case MapHash:
>+    case GetMapBucket:
>+    case LoadFromJSMapBucket:
>+    case IsNonEmptyMapBucket:
>     case Unreachable:
>     case ExtractOSREntryLocal:
>     case CheckTierUpInLoop:
>Index: Source/JavaScriptCore/dfg/DFGEdge.h
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGEdge.h	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGEdge.h	(working copy)
>@@ -189,7 +189,7 @@ private:
>     friend class AdjacencyList;
>     
> #if USE(JSVALUE64)
>-    static uint32_t shift() { return 7; }
>+    static constexpr uint32_t shift() { return 8; }
>     
>     static uintptr_t makeWord(Node* node, UseKind useKind, ProofStatus proofStatus, KillStatus killStatus)
>     {
>@@ -197,8 +197,21 @@ private:
>         uintptr_t shiftedValue = bitwise_cast<uintptr_t>(node) << shift();
>         ASSERT((shiftedValue >> shift()) == bitwise_cast<uintptr_t>(node));
>         ASSERT(useKind >= 0 && useKind < LastUseKind);
>-        ASSERT((static_cast<uintptr_t>(LastUseKind) << 2) <= (static_cast<uintptr_t>(2) << shift()));
>-        return shiftedValue | (static_cast<uintptr_t>(useKind) << 2) | (DFG::doesKill(killStatus) << 1) | static_cast<uintptr_t>(DFG::isProved(proofStatus));
>+        static_assert((static_cast<uintptr_t>(LastUseKind) << 2) < (static_cast<uintptr_t>(1) << shift()), "We rely on this being true to not clobber the node pointer.");
>+        uintptr_t result = shiftedValue | (static_cast<uintptr_t>(useKind) << 2) | (DFG::doesKill(killStatus) << 1) | static_cast<uintptr_t>(DFG::isProved(proofStatus));
>+        if (!ASSERT_DISABLED) {
>+            union U {
>+                U() { word = 0; }
>+                uintptr_t word;
>+                Edge edge;
>+            } u;
>+            u.word = result;
>+            ASSERT(u.edge.useKindUnchecked() == useKind);
>+            ASSERT(u.edge.node() == node);
>+            ASSERT(u.edge.proofStatusUnchecked() == proofStatus);
>+            ASSERT(u.edge.killStatusUnchecked() == killStatus);
>+        }
>+        return result;
>     }
>     
> #else
>Index: Source/JavaScriptCore/dfg/DFGFixupPhase.cpp
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGFixupPhase.cpp	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGFixupPhase.cpp	(working copy)
>@@ -1545,6 +1545,29 @@ private:
>             break;
>         }
> 
>+        case GetMapBucket:
>+            if (node->child1().useKind() == MapObjectUse)
>+                fixEdge<MapObjectUse>(node->child1());
>+            else if (node->child1().useKind() == SetObjectUse)
>+                fixEdge<SetObjectUse>(node->child1());
>+            else
>+                RELEASE_ASSERT_NOT_REACHED();
>+            fixEdge<UntypedUse>(node->child2());
>+            fixEdge<Int32Use>(node->child3());
>+            break;
>+
>+        case LoadFromJSMapBucket:
>+            fixEdge<KnownCellUse>(node->child1());
>+            break;
>+
>+        case IsNonEmptyMapBucket:
>+            fixEdge<KnownCellUse>(node->child1());
>+            break;
>+
>+        case MapHash:
>+            fixEdge<UntypedUse>(node->child1());
>+            break;
>+
> #if !ASSERT_DISABLED
>         // Have these no-op cases here to ensure that nobody forgets to add handlers for new opcodes.
>         case SetArgument:
>Index: Source/JavaScriptCore/dfg/DFGHeapLocation.cpp
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGHeapLocation.cpp	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGHeapLocation.cpp	(working copy)
>@@ -143,6 +143,15 @@ void printInternal(PrintStream& out, Loc
>     case RegExpObjectLastIndexLoc:
>         out.print("RegExpObjectLastIndexLoc");
>         return;
>+    case MapBucketLoc:
>+        out.print("MapBucketLoc");
>+        return;
>+    case JSMapGetLoc:
>+        out.print("JSMapGetLoc");
>+        return;
>+    case MapHasLoc:
>+        out.print("MapHasLoc");
>+        return;
>     }
>     
>     RELEASE_ASSERT_NOT_REACHED();
>Index: Source/JavaScriptCore/dfg/DFGHeapLocation.h
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGHeapLocation.h	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGHeapLocation.h	(working copy)
>@@ -58,7 +58,10 @@ enum LocationKind {
>     StructureLoc,
>     TypedArrayByteOffsetLoc,
>     StackLoc,
>-    StackPayloadLoc
>+    StackPayloadLoc,
>+    MapBucketLoc,
>+    JSMapGetLoc,
>+    MapHasLoc
> };
> 
> class HeapLocation {
>Index: Source/JavaScriptCore/dfg/DFGNode.h
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGNode.h	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGNode.h	(working copy)
>@@ -1419,6 +1419,7 @@ public:
>         case StringReplace:
>         case StringReplaceRegExp:
>         case ToNumber:
>+        case LoadFromJSMapBucket:
>             return true;
>         default:
>             return false;
>Index: Source/JavaScriptCore/dfg/DFGNodeType.h
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGNodeType.h	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGNodeType.h	(working copy)
>@@ -388,7 +388,12 @@ namespace JSC { namespace DFG {
>     macro(GetPropertyEnumerator, NodeMustGenerate | NodeResultJS) \
>     macro(GetEnumeratorStructurePname, NodeMustGenerate | NodeResultJS) \
>     macro(GetEnumeratorGenericPname, NodeMustGenerate | NodeResultJS) \
>-    macro(ToIndexString, NodeResultJS)
>+    macro(ToIndexString, NodeResultJS) \
>+    /* Hashing nodes for JSMap and JSSet */ \
>+    macro(MapHash, NodeResultInt32) \
>+    macro(GetMapBucket, NodeResultJS) \
>+    macro(LoadFromJSMapBucket, NodeResultJS) \
>+    macro(IsNonEmptyMapBucket, NodeResultBoolean) \
> 
> // This enum generates a monotonically increasing id for all Node types,
> // and is used by the subsequent enum to fill out the id (as accessed via the NodeIdMask).
>Index: Source/JavaScriptCore/dfg/DFGOperations.cpp
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGOperations.cpp	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGOperations.cpp	(working copy)
>@@ -50,6 +50,8 @@
> #include "JSCInlines.h"
> #include "JSGenericTypedArrayViewConstructorInlines.h"
> #include "JSLexicalEnvironment.h"
>+#include "JSMap.h"
>+#include "JSSet.h"
> #include "ObjectConstructor.h"
> #include "Repatch.h"
> #include "ScopedArguments.h"
>@@ -1803,6 +1805,34 @@ void JIT_OPERATION operationPutDynamicVa
>     scope->methodTable()->put(scope, exec, ident, JSValue::decode(value), slot);
> }
> 
>+int32_t JIT_OPERATION operationMapHash(ExecState* exec, EncodedJSValue input)
>+{
>+    VM& vm = exec->vm();
>+    NativeCallFrameTracer tracer(&vm, exec);
>+
>+    return jsMapHash(exec, vm, normalizeMapKey(JSValue::decode(input)));
>+}
>+
>+JSCell* JIT_OPERATION operationJSMapFindBucket(ExecState* exec, JSCell* map, EncodedJSValue key, int32_t hash)
>+{
>+    VM& vm = exec->vm();
>+    NativeCallFrameTracer tracer(&vm, exec);
>+    JSMap::BucketType** bucket = jsCast<JSMap*>(map)->findBucket(exec, JSValue::decode(key), hash);
>+    if (!bucket)
>+        return nullptr;
>+    return *bucket;
>+}
>+
>+JSCell* JIT_OPERATION operationJSSetFindBucket(ExecState* exec, JSCell* map, EncodedJSValue key, int32_t hash)
>+{
>+    VM& vm = exec->vm();
>+    NativeCallFrameTracer tracer(&vm, exec);
>+    JSSet::BucketType** bucket = jsCast<JSSet*>(map)->findBucket(exec, JSValue::decode(key), hash);
>+    if (!bucket)
>+        return nullptr;
>+    return *bucket;
>+}
>+
> extern "C" void JIT_OPERATION triggerReoptimizationNow(CodeBlock* codeBlock, OSRExitBase* exit)
> {
>     // It's sort of preferable that we don't GC while in here. Anyways, doing so wouldn't
>Index: Source/JavaScriptCore/dfg/DFGOperations.h
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGOperations.h	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGOperations.h	(working copy)
>@@ -142,6 +142,10 @@ char* JIT_OPERATION operationEnsureArray
> StringImpl* JIT_OPERATION operationResolveRope(ExecState*, JSString*);
> JSString* JIT_OPERATION operationSingleCharacterString(ExecState*, int32_t);
> 
>+int32_t JIT_OPERATION operationMapHash(ExecState*, EncodedJSValue input);
>+JSCell* JIT_OPERATION operationJSMapFindBucket(ExecState*, JSCell*, EncodedJSValue, int32_t);
>+JSCell* JIT_OPERATION operationJSSetFindBucket(ExecState*, JSCell*, EncodedJSValue, int32_t);
>+
> JSCell* JIT_OPERATION operationNewStringObject(ExecState*, JSString*, Structure*);
> JSCell* JIT_OPERATION operationToStringOnCell(ExecState*, JSCell*);
> JSCell* JIT_OPERATION operationToString(ExecState*, EncodedJSValue);
>Index: Source/JavaScriptCore/dfg/DFGPredictionPropagationPhase.cpp
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGPredictionPropagationPhase.cpp	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGPredictionPropagationPhase.cpp	(working copy)
>@@ -711,6 +711,7 @@ private:
>         case GetGlobalLexicalVariable:
>         case GetClosureVar:
>         case GetFromArguments:
>+        case LoadFromJSMapBucket:
>         case ToNumber: {
>             setPrediction(m_currentNode->getHeapPrediction());
>             break;
>@@ -741,6 +742,16 @@ private:
>             break;
>         }
> 
>+        case MapHash:
>+            setPrediction(SpecInt32Only);
>+            break;
>+        case GetMapBucket:
>+            setPrediction(SpecCellOther);
>+            break;
>+        case IsNonEmptyMapBucket:
>+            setPrediction(SpecBoolean);
>+            break;
>+
>         case GetRestLength: {
>             setPrediction(SpecInt32Only);
>             break;
>Index: Source/JavaScriptCore/dfg/DFGSafeToExecute.h
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGSafeToExecute.h	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGSafeToExecute.h	(working copy)
>@@ -58,6 +58,8 @@ public:
>         case FunctionUse:
>         case FinalObjectUse:
>         case RegExpObjectUse:
>+        case MapObjectUse:
>+        case SetObjectUse:
>         case ObjectOrOtherUse:
>         case StringIdentUse:
>         case StringUse:
>@@ -355,6 +357,10 @@ bool safeToExecute(AbstractStateType& st
>     case GetDynamicVar:
>     case PutDynamicVar:
>     case ResolveScope:
>+    case MapHash:
>+    case GetMapBucket:
>+    case LoadFromJSMapBucket:
>+    case IsNonEmptyMapBucket:
>         return true;
> 
>     case BottomValue:
>Index: Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp	(working copy)
>@@ -37,6 +37,7 @@
> #include "DFGSlowPathGenerator.h"
> #include "DirectArguments.h"
> #include "GetterSetter.h"
>+#include "HashMapImpl.h"
> #include "JSEnvironmentRecord.h"
> #include "JSLexicalEnvironment.h"
> #include "JSPropertyNameEnumerator.h"
>@@ -4720,6 +4721,82 @@ void SpeculativeJIT::compile(Node* node)
>         break;
>     }
> 
>+    case MapHash: {
>+        JSValueOperand input(this, node->child1());
>+
>+        JSValueRegs inputRegs = input.jsValueRegs();
>+
>+        GPRFlushedCallResult result(this);
>+        GPRReg resultGPR = result.gpr();
>+
>+        flushRegisters();
>+        callOperation(operationMapHash, resultGPR, inputRegs);
>+        m_jit.exceptionCheck();
>+        int32Result(resultGPR, node);
>+        break;
>+    }
>+
>+    case GetMapBucket: {
>+        SpeculateCellOperand map(this, node->child1());
>+        JSValueOperand key(this, node->child2());
>+        SpeculateInt32Operand hash(this, node->child3());
>+        GPRFlushedCallResult result(this);
>+
>+        GPRReg mapGPR = map.gpr();
>+        JSValueRegs keyRegs = key.jsValueRegs();
>+        GPRReg hashGPR = hash.gpr();
>+        GPRReg resultGPR = result.gpr();
>+
>+        if (node->child1().useKind() == MapObjectUse)
>+            speculateMapObject(node->child1(), mapGPR);
>+        else if (node->child1().useKind() == SetObjectUse)
>+            speculateSetObject(node->child1(), mapGPR);
>+        else
>+            RELEASE_ASSERT_NOT_REACHED();
>+
>+        flushRegisters();
>+        if (node->child1().useKind() == MapObjectUse)
>+            callOperation(operationJSMapFindBucket, resultGPR, mapGPR, keyRegs, hashGPR);
>+        else
>+            callOperation(operationJSSetFindBucket, resultGPR, mapGPR, keyRegs, hashGPR);
>+        m_jit.exceptionCheck();
>+        cellResult(resultGPR, node);
>+        break;
>+    }
>+
>+    case LoadFromJSMapBucket: {
>+        SpeculateCellOperand bucket(this, node->child1());
>+        GPRTemporary resultPayload(this);
>+        GPRTemporary resultTag(this);
>+
>+        GPRReg bucketGPR = bucket.gpr();
>+        GPRReg resultPayloadGPR = resultPayload.gpr();
>+        GPRReg resultTagGPR = resultTag.gpr();
>+
>+        auto notBucket = m_jit.branchTestPtr(MacroAssembler::Zero, bucketGPR);
>+        m_jit.loadValue(MacroAssembler::Address(bucketGPR, HashMapBucket<HashMapBucketDataKeyValue>::offsetOfValue()), JSValueRegs(resultTagGPR, resultPayloadGPR));
>+        auto done = m_jit.jump();
>+
>+        notBucket.link(&m_jit);
>+        m_jit.move(TrustedImm32(JSValue::UndefinedTag), resultTagGPR);
>+        m_jit.move(TrustedImm32(0), resultPayloadGPR);
>+        done.link(&m_jit);
>+        jsValueResult(resultTagGPR, resultPayloadGPR, node);
>+        break;
>+    }
>+
>+    case IsNonEmptyMapBucket: {
>+        SpeculateCellOperand bucket(this, node->child1());
>+        GPRTemporary result(this);
>+
>+        GPRReg bucketGPR = bucket.gpr();
>+        GPRReg resultGPR = result.gpr();
>+
>+        m_jit.comparePtr(MacroAssembler::NotEqual, bucketGPR, TrustedImm32(0), resultGPR);
>+        booleanResult(resultGPR, node);
>+        break;
>+    }
>+
>     case Flush:
>         break;
> 
>Index: Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp	(working copy)
>@@ -39,7 +39,9 @@
> #include "JSCInlines.h"
> #include "JSEnvironmentRecord.h"
> #include "JSLexicalEnvironment.h"
>+#include "JSMap.h"
> #include "JSPropertyNameEnumerator.h"
>+#include "JSSet.h"
> #include "ObjectPrototype.h"
> #include "SetupVarargsFrame.h"
> #include "SpillRegistersMode.h"
>@@ -4615,6 +4617,168 @@ void SpeculativeJIT::compile(Node* node)
>         break;
>     }
> 
>+    case MapHash: {
>+        JSValueOperand input(this, node->child1());
>+        GPRTemporary temp(this);
>+        GPRTemporary result(this);
>+
>+        GPRReg inputGPR = input.gpr();
>+        GPRReg resultGPR = result.gpr();
>+        GPRReg tempGPR = temp.gpr();
>+
>+        MacroAssembler::JumpList straightHash;
>+        MacroAssembler::JumpList done;
>+        auto isNotCell = m_jit.branchIfNotCell(inputGPR);
>+        MacroAssembler::JumpList slowPath;
>+        straightHash.append(m_jit.branch8(MacroAssembler::NotEqual, MacroAssembler::Address(inputGPR, JSCell::typeInfoTypeOffset()), TrustedImm32(StringType)));
>+        m_jit.loadPtr(MacroAssembler::Address(inputGPR, JSString::offsetOfValue()), resultGPR);
>+        slowPath.append(m_jit.branchTestPtr(MacroAssembler::Zero, resultGPR));
>+        m_jit.load32(MacroAssembler::Address(resultGPR, StringImpl::flagsOffset()), resultGPR);
>+        m_jit.urshift64(MacroAssembler::TrustedImm32(6), resultGPR);
>+        slowPath.append(m_jit.branchTest32(MacroAssembler::Zero, resultGPR));
>+        done.append(m_jit.jump());
>+
>+        isNotCell.link(&m_jit);
>+        straightHash.append(m_jit.branchIfNotNumber(inputGPR));
>+        straightHash.append(m_jit.branchIfInt32(JSValueRegs(inputGPR)));
>+        slowPath.append(m_jit.jump());
>+
>+        straightHash.link(&m_jit);
>+        m_jit.move(inputGPR, resultGPR);
>+        m_jit.WangsInt64Hash(resultGPR, tempGPR);
>+        done.append(m_jit.jump());
>+
>+        slowPath.link(&m_jit);
>+        silentSpillAllRegisters(resultGPR);
>+        callOperation(operationMapHash, resultGPR, inputGPR);
>+        silentFillAllRegisters(resultGPR);
>+        m_jit.exceptionCheck();
>+
>+        done.link(&m_jit);
>+        int32Result(resultGPR, node);
>+        break;
>+    }
>+    case GetMapBucket: {
>+        SpeculateCellOperand map(this, node->child1());
>+        JSValueOperand key(this, node->child2());
>+        SpeculateInt32Operand hash(this, node->child3());
>+        GPRTemporary mask(this);
>+        GPRTemporary index(this);
>+        GPRTemporary buffer(this);
>+        GPRTemporary bucket(this);
>+        GPRTemporary result(this);
>+
>+        GPRReg hashGPR = hash.gpr();
>+        GPRReg mapGPR = map.gpr();
>+        GPRReg maskGPR = mask.gpr();
>+        GPRReg indexGPR = index.gpr();
>+        GPRReg bufferGPR = buffer.gpr();
>+        GPRReg bucketGPR = bucket.gpr();
>+        GPRReg keyGPR = key.gpr();
>+        GPRReg resultGPR = result.gpr();
>+
>+        if (node->child1().useKind() == MapObjectUse)
>+            speculateMapObject(node->child1(), mapGPR);
>+        else if (node->child1().useKind() == SetObjectUse)
>+            speculateSetObject(node->child1(), mapGPR);
>+        else
>+            RELEASE_ASSERT_NOT_REACHED();
>+
>+        m_jit.loadPtr(MacroAssembler::Address(mapGPR, node->child1().useKind() == MapObjectUse ? JSMap::offsetOfHashMapImpl() : JSSet::offsetOfHashMapImpl()), bufferGPR);
>+        m_jit.load32(MacroAssembler::Address(bufferGPR, HashMapImpl<HashMapBucket<HashMapBucketDataKey>>::offsetOfCapacity()), maskGPR);
>+        m_jit.loadPtr(MacroAssembler::Address(bufferGPR, HashMapImpl<HashMapBucket<HashMapBucketDataKey>>::offsetOfBuffer()), bufferGPR);
>+        m_jit.sub32(TrustedImm32(1), maskGPR);
>+        m_jit.move(hashGPR, indexGPR);
>+
>+        MacroAssembler::Label loop = m_jit.label();
>+        MacroAssembler::JumpList done;
>+        MacroAssembler::JumpList slowPathCases;
>+        MacroAssembler::JumpList loopAround;
>+
>+        m_jit.and32(maskGPR, indexGPR);
>+        m_jit.loadPtr(MacroAssembler::BaseIndex(bufferGPR, indexGPR, MacroAssembler::TimesEight), bucketGPR);
>+        m_jit.move(bucketGPR, resultGPR);
>+        auto notPresentInTable = m_jit.branchPtr(MacroAssembler::Equal, 
>+            bucketGPR, TrustedImmPtr(HashMapImpl<HashMapBucket<HashMapBucketDataKey>>::emptyValue()));
>+        loopAround.append(m_jit.branchPtr(MacroAssembler::Equal, 
>+            bucketGPR, TrustedImmPtr(HashMapImpl<HashMapBucket<HashMapBucketDataKey>>::deletedValue())));
>+
>+        m_jit.load64(MacroAssembler::Address(bucketGPR, HashMapBucket<HashMapBucketDataKey>::offsetOfKey()), bucketGPR);
>+
>+        // Perform Object.is()
>+        done.append(m_jit.branch64(MacroAssembler::Equal, bucketGPR, keyGPR)); // They're definitely the same value, we found the bucket we were looking for!
>+        auto oneIsntCell = m_jit.branchIfNotCell(JSValueRegs(bucketGPR));
>+        // first is a cell here.
>+        loopAround.append(m_jit.branchIfNotCell(JSValueRegs(keyGPR)));
>+        // Both are cells here.
>+        loopAround.append(m_jit.branch8(JITCompiler::NotEqual,
>+            JITCompiler::Address(bucketGPR, JSCell::typeInfoTypeOffset()), TrustedImm32(StringType)));
>+        // The first is a string here.
>+        slowPathCases.append(m_jit.branch8(JITCompiler::Equal,
>+            JITCompiler::Address(keyGPR, JSCell::typeInfoTypeOffset()), TrustedImm32(StringType)));
>+        // The first is a string, but the second is not, we continue to loop around.
>+        loopAround.append(m_jit.jump());
>+
>+        oneIsntCell.link(&m_jit);
>+        // We've already done a 64-bit compare at this point, so if one is not a number, they're definitely not equal.
>+        loopAround.append(m_jit.branchIfNotNumber(bucketGPR));
>+        loopAround.append(m_jit.branchIfNotNumber(keyGPR));
>+        // Both are definitely numbers. If we see a double, we go to the slow path.
>+        slowPathCases.append(m_jit.branchIfNotInt32(bucketGPR));
>+        slowPathCases.append(m_jit.branchIfNotInt32(keyGPR));
>+        
>+        loopAround.link(&m_jit);
>+        m_jit.add32(TrustedImm32(1), indexGPR);
>+        m_jit.jump().linkTo(loop, &m_jit);
>+
>+        slowPathCases.link(&m_jit);
>+        silentSpillAllRegisters(indexGPR);
>+        if (node->child1().useKind() == MapObjectUse)
>+            callOperation(operationJSMapFindBucket, resultGPR, mapGPR, keyGPR, hashGPR);
>+        else
>+            callOperation(operationJSSetFindBucket, resultGPR, mapGPR, keyGPR, hashGPR);
>+        silentFillAllRegisters(indexGPR);
>+        m_jit.exceptionCheck();
>+        done.append(m_jit.jump());
>+
>+        notPresentInTable.link(&m_jit);
>+        m_jit.move(TrustedImmPtr(nullptr), resultGPR);
>+        done.link(&m_jit);
>+        cellResult(resultGPR, node);
>+        break;
>+    }
>+
>+    case LoadFromJSMapBucket: {
>+        SpeculateCellOperand bucket(this, node->child1());
>+        GPRTemporary result(this);
>+
>+        GPRReg bucketGPR = bucket.gpr();
>+        GPRReg resultGPR = result.gpr();
>+
>+        auto notBucket = m_jit.branchTestPtr(MacroAssembler::Zero, bucketGPR);
>+        m_jit.load64(MacroAssembler::Address(bucketGPR, HashMapBucket<HashMapBucketDataKeyValue>::offsetOfValue()), resultGPR);
>+        auto done = m_jit.jump();
>+
>+        notBucket.link(&m_jit);
>+        m_jit.move(MacroAssembler::TrustedImm64(JSValue::encode(jsUndefined())), resultGPR);
>+        done.link(&m_jit);
>+        jsValueResult(resultGPR, node);
>+        break;
>+    }
>+
>+    case IsNonEmptyMapBucket: {
>+        SpeculateCellOperand bucket(this, node->child1());
>+        GPRTemporary result(this);
>+
>+        GPRReg bucketGPR = bucket.gpr();
>+        GPRReg resultGPR = result.gpr();
>+
>+        m_jit.comparePtr(MacroAssembler::NotEqual, bucketGPR, TrustedImm32(0), resultGPR);
>+        m_jit.or32(TrustedImm32(ValueFalse), resultGPR);
>+        jsValueResult(resultGPR, node, DataFormatJSBoolean);
>+        break;
>+    }
>+
>     case IsObject: {
>         JSValueOperand value(this, node->child1());
>         GPRTemporary result(this, Reuse, value);
>Index: Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp	(working copy)
>@@ -7381,6 +7381,34 @@ void SpeculativeJIT::speculateRegExpObje
>     speculateRegExpObject(edge, operand.gpr());
> }
> 
>+void SpeculativeJIT::speculateMapObject(Edge edge, GPRReg cell)
>+{
>+    speculateCellType(edge, cell, SpecMapObject, JSMapType);
>+}
>+
>+void SpeculativeJIT::speculateMapObject(Edge edge)
>+{
>+    if (!needsTypeCheck(edge, SpecMapObject))
>+        return;
>+
>+    SpeculateCellOperand operand(this, edge);
>+    speculateMapObject(edge, operand.gpr());
>+}
>+
>+void SpeculativeJIT::speculateSetObject(Edge edge, GPRReg cell)
>+{
>+    speculateCellType(edge, cell, SpecSetObject, JSSetType);
>+}
>+
>+void SpeculativeJIT::speculateSetObject(Edge edge)
>+{
>+    if (!needsTypeCheck(edge, SpecSetObject))
>+        return;
>+
>+    SpeculateCellOperand operand(this, edge);
>+    speculateSetObject(edge, operand.gpr());
>+}
>+
> void SpeculativeJIT::speculateObjectOrOther(Edge edge)
> {
>     if (!needsTypeCheck(edge, SpecObject | SpecOther))
>@@ -7668,6 +7696,12 @@ void SpeculativeJIT::speculate(Node*, Ed
>     case RegExpObjectUse:
>         speculateRegExpObject(edge);
>         break;
>+    case MapObjectUse:
>+        speculateMapObject(edge);
>+        break;
>+    case SetObjectUse:
>+        speculateSetObject(edge);
>+        break;
>     case ObjectOrOtherUse:
>         speculateObjectOrOther(edge);
>         break;
>Index: Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h	(working copy)
>@@ -1291,6 +1291,12 @@ public:
> 
> #if USE(JSVALUE64)
> 
>+    JITCompiler::Call callOperation(C_JITOperation_ECJZ operation, GPRReg result, GPRReg arg1, GPRReg arg2, GPRReg arg3)
>+    {
>+        m_jit.setupArgumentsWithExecState(arg1, arg2, arg3);
>+        return appendCallSetResult(operation, result);
>+    }
>+
>     JITCompiler::Call callOperation(J_JITOperation_EJJMic operation, JSValueRegs result, JSValueRegs arg1, JSValueRegs arg2, TrustedImmPtr mathIC)
>     {
>         m_jit.setupArgumentsWithExecState(arg1.gpr(), arg2.gpr(), mathIC);
>@@ -1671,6 +1677,12 @@ public:
>         return appendCall(operation);
>     }
> 
>+    JITCompiler::Call callOperation(Z_JITOperation_EJ operation, GPRReg result, GPRReg arg1)
>+    {
>+        m_jit.setupArgumentsWithExecState(arg1);
>+        return appendCallSetResult(operation, result);
>+    }
>+
>     JITCompiler::Call callOperation(Z_JITOperation_EJZZ operation, GPRReg result, GPRReg arg1, unsigned arg2, unsigned arg3)
>     {
>         m_jit.setupArgumentsWithExecState(arg1, TrustedImm32(arg2), TrustedImm32(arg3));
>@@ -1719,6 +1731,18 @@ public:
>     }
> #else // USE(JSVALUE32_64)
> 
>+    JITCompiler::Call callOperation(C_JITOperation_ECJZ operation, GPRReg result, GPRReg arg1, JSValueRegs arg2, GPRReg arg3)
>+    {
>+        m_jit.setupArgumentsWithExecState(arg1, arg2.payloadGPR(), arg2.tagGPR(), arg3);
>+        return appendCallSetResult(operation, result);
>+    }
>+
>+    JITCompiler::Call callOperation(Z_JITOperation_EJ operation, GPRReg result, JSValueRegs arg1)
>+    {
>+        m_jit.setupArgumentsWithExecState(EABI_32BIT_DUMMY_ARG arg1.payloadGPR(), arg1.tagGPR());
>+        return appendCallSetResult(operation, result);
>+    }
>+
>     JITCompiler::Call callOperation(J_JITOperation_EJJMic operation, JSValueRegs result, JSValueRegs arg1, JSValueRegs arg2, TrustedImmPtr mathIC)
>     {
>         m_jit.setupArgumentsWithExecState(EABI_32BIT_DUMMY_ARG arg1.payloadGPR(), arg1.tagGPR(), arg2.payloadGPR(), arg2.tagGPR(), mathIC);
>@@ -2656,6 +2680,10 @@ public:
>     void speculateFinalObject(Edge);
>     void speculateRegExpObject(Edge, GPRReg cell);
>     void speculateRegExpObject(Edge);
>+    void speculateMapObject(Edge);
>+    void speculateMapObject(Edge, GPRReg cell);
>+    void speculateSetObject(Edge);
>+    void speculateSetObject(Edge, GPRReg cell);
>     void speculateObjectOrOther(Edge);
>     void speculateString(Edge edge, GPRReg cell);
>     void speculateStringIdentAndLoadStorage(Edge edge, GPRReg string, GPRReg storage);
>Index: Source/JavaScriptCore/dfg/DFGUseKind.cpp
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGUseKind.cpp	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGUseKind.cpp	(working copy)
>@@ -94,6 +94,12 @@ void printInternal(PrintStream& out, Use
>     case RegExpObjectUse:
>         out.print("RegExpObject");
>         return;
>+    case MapObjectUse:
>+        out.print("MapObjectUse");
>+        return;
>+    case SetObjectUse:
>+        out.print("SetObjectUse");
>+        return;
>     case ObjectOrOtherUse:
>         out.print("ObjectOrOther");
>         return;
>Index: Source/JavaScriptCore/dfg/DFGUseKind.h
>===================================================================
>--- Source/JavaScriptCore/dfg/DFGUseKind.h	(revision 205305)
>+++ Source/JavaScriptCore/dfg/DFGUseKind.h	(working copy)
>@@ -63,6 +63,8 @@ enum UseKind {
>     KnownStringUse,
>     KnownPrimitiveUse, // This bizarre type arises for op_strcat, which has a bytecode guarantee that it will only see primitives (i.e. not objects).
>     SymbolUse,
>+    MapObjectUse,
>+    SetObjectUse,
>     StringObjectUse,
>     StringOrStringObjectUse,
>     NotStringVarUse,
>@@ -134,6 +136,10 @@ inline SpeculatedType typeFilterFor(UseK
>         return SpecHeapTop & ~SpecObject;
>     case SymbolUse:
>         return SpecSymbol;
>+    case MapObjectUse:
>+        return SpecMapObject;
>+    case SetObjectUse:
>+        return SpecSetObject;
>     case StringObjectUse:
>         return SpecStringObject;
>     case StringOrStringObjectUse:
>@@ -221,6 +227,8 @@ inline bool isCell(UseKind kind)
>     case SymbolUse:
>     case StringObjectUse:
>     case StringOrStringObjectUse:
>+    case MapObjectUse:
>+    case SetObjectUse:
>         return true;
>     default:
>         return false;
>Index: Source/JavaScriptCore/ftl/FTLAbstractHeapRepository.h
>===================================================================
>--- Source/JavaScriptCore/ftl/FTLAbstractHeapRepository.h	(revision 205305)
>+++ Source/JavaScriptCore/ftl/FTLAbstractHeapRepository.h	(working copy)
>@@ -32,6 +32,8 @@
> #include "DFGArrayMode.h"
> #include "FTLAbstractHeap.h"
> #include "IndexingType.h"
>+#include "JSMap.h"
>+#include "JSSet.h"
> 
> namespace JSC { namespace FTL {
> 
>@@ -102,7 +104,13 @@ namespace JSC { namespace FTL {
>     macro(Structure_classInfo, Structure::classInfoOffset()) \
>     macro(Structure_globalObject, Structure::globalObjectOffset()) \
>     macro(Structure_prototype, Structure::prototypeOffset()) \
>-    macro(Structure_structureID, Structure::structureIDOffset())
>+    macro(Structure_structureID, Structure::structureIDOffset()) \
>+    macro(JSMap_hashMapImpl, JSMap::offsetOfHashMapImpl()) \
>+    macro(JSSet_hashMapImpl, JSSet::offsetOfHashMapImpl()) \
>+    macro(HashMapImpl_capacity, HashMapImpl<HashMapBucket<HashMapBucketDataKey>>::offsetOfCapacity()) \
>+    macro(HashMapImpl_buffer,  HashMapImpl<HashMapBucket<HashMapBucketDataKey>>::offsetOfBuffer()) \
>+    macro(HashMapBucket_value, HashMapBucket<HashMapBucketDataKeyValue>::offsetOfValue()) \
>+    macro(HashMapBucket_key, HashMapBucket<HashMapBucketDataKeyValue>::offsetOfKey()) \
> 
> #define FOR_EACH_INDEXED_ABSTRACT_HEAP(macro) \
>     macro(DirectArguments_storage, DirectArguments::storageOffset(), sizeof(EncodedJSValue)) \
>Index: Source/JavaScriptCore/ftl/FTLCapabilities.cpp
>===================================================================
>--- Source/JavaScriptCore/ftl/FTLCapabilities.cpp	(revision 205305)
>+++ Source/JavaScriptCore/ftl/FTLCapabilities.cpp	(working copy)
>@@ -180,6 +180,10 @@ inline CapabilityLevel canCompile(Node* 
>     case ThrowReferenceError:
>     case Unreachable:
>     case IsJSArray:
>+    case MapHash:
>+    case GetMapBucket:
>+    case LoadFromJSMapBucket:
>+    case IsNonEmptyMapBucket:
>     case IsEmpty:
>     case IsUndefined:
>     case IsBoolean:
>@@ -437,6 +441,8 @@ CapabilityLevel canCompile(Graph& graph)
>                 case StringObjectUse:
>                 case StringOrStringObjectUse:
>                 case SymbolUse:
>+                case MapObjectUse:
>+                case SetObjectUse:
>                 case FinalObjectUse:
>                 case RegExpObjectUse:
>                 case NotCellUse:
>Index: Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp
>===================================================================
>--- Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp	(revision 205305)
>+++ Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp	(working copy)
>@@ -70,6 +70,7 @@
> #include "JSCInlines.h"
> #include "JSGeneratorFunction.h"
> #include "JSLexicalEnvironment.h"
>+#include "JSMap.h"
> #include "OperandsInlines.h"
> #include "ScopedArguments.h"
> #include "ScopedArgumentsTable.h"
>@@ -898,6 +899,18 @@ private:
>         case IsJSArray:
>             compileIsJSArray();
>             break;
>+        case MapHash:
>+            compileMapHash();
>+            break;
>+        case GetMapBucket:
>+            compileGetMapBucket();
>+            break;
>+        case LoadFromJSMapBucket:
>+            compileLoadFromJSMapBucket();
>+            break;
>+        case IsNonEmptyMapBucket:
>+            compileIsNonEmptyMapBucket();
>+            break;
>         case IsObject:
>             compileIsObject();
>             break;
>@@ -6351,6 +6364,228 @@ private:
>         setBoolean(m_out.phi(Int32, notCellResult, cellResult));
>     }
> 
>+    void compileMapHash()
>+    {
>+        LValue value = lowJSValue(m_node->child1());
>+
>+        LBasicBlock isCellCase = m_out.newBlock();
>+        LBasicBlock notCell = m_out.newBlock();
>+        LBasicBlock slowCase = m_out.newBlock();
>+        LBasicBlock straightHash = m_out.newBlock();
>+        LBasicBlock isNumberCase = m_out.newBlock();
>+        LBasicBlock isStringCase = m_out.newBlock();
>+        LBasicBlock nonEmptyStringCase = m_out.newBlock();
>+        LBasicBlock continuation = m_out.newBlock();
>+
>+        m_out.branch(
>+            isCell(value, provenType(m_node->child1())), unsure(isCellCase), unsure(notCell));
>+
>+        LBasicBlock lastNext = m_out.appendTo(isCellCase, isStringCase);
>+        LValue isString = m_out.equal(m_out.load8ZeroExt32(value, m_heaps.JSCell_typeInfoType), m_out.constInt32(StringType));
>+        m_out.branch(
>+            isString, unsure(isStringCase), unsure(straightHash));
>+
>+        m_out.appendTo(isStringCase, nonEmptyStringCase);
>+        LValue stringImpl = m_out.loadPtr(value, m_heaps.JSString_value);
>+        m_out.branch(
>+            m_out.equal(stringImpl, m_out.constIntPtr(0)), rarely(slowCase), usually(nonEmptyStringCase));
>+
>+        m_out.appendTo(nonEmptyStringCase, notCell);
>+        LValue hash = m_out.lShr(m_out.load32(stringImpl, m_heaps.StringImpl_hashAndFlags), m_out.constInt32(6));
>+        ValueFromBlock nonEmptyStringHashResult = m_out.anchor(hash);
>+        m_out.branch(m_out.equal(hash, m_out.constInt32(0)),
>+            rarely(slowCase), usually(continuation));
>+
>+        m_out.appendTo(notCell, isNumberCase);
>+        m_out.branch(
>+            isNumber(value), unsure(isNumberCase), unsure(straightHash));
>+
>+        m_out.appendTo(isNumberCase, straightHash);
>+        m_out.branch(
>+            isInt32(value), unsure(straightHash), unsure(slowCase));
>+
>+        m_out.appendTo(straightHash, slowCase);
>+        // key += ~(key << 32);
>+        LValue key = value;
>+        LValue temp = key;
>+        temp = m_out.shl(temp, m_out.constInt32(32));
>+        temp = m_out.bitNot(temp);
>+        key = m_out.add(key, temp);
>+        // key ^= (key >> 22);
>+        temp = key;
>+        temp = m_out.lShr(temp, m_out.constInt32(22));
>+        key = m_out.bitXor(key, temp);
>+        // key += ~(key << 13);
>+        temp = key;
>+        temp = m_out.shl(temp, m_out.constInt32(13));
>+        temp = m_out.bitNot(temp);
>+        key = m_out.add(key, temp);
>+        // key ^= (key >> 8);
>+        temp = key;
>+        temp = m_out.lShr(temp, m_out.constInt32(8));
>+        key = m_out.bitXor(key, temp);
>+        // key += (key << 3);
>+        temp = key;
>+        temp = m_out.shl(temp, m_out.constInt32(3));
>+        key = m_out.add(key, temp);
>+        // key ^= (key >> 15);
>+        temp = key;
>+        temp = m_out.lShr(temp, m_out.constInt32(15));
>+        key = m_out.bitXor(key, temp);
>+        // key += ~(key << 27);
>+        temp = key;
>+        temp = m_out.shl(temp, m_out.constInt32(27));
>+        temp = m_out.bitNot(temp);
>+        key = m_out.add(key, temp);
>+        // key ^= (key >> 31);
>+        temp = key;
>+        temp = m_out.lShr(temp, m_out.constInt32(31));
>+        key = m_out.bitXor(key, temp);
>+        key = m_out.castToInt32(key);
>+
>+        ValueFromBlock fastResult = m_out.anchor(key);
>+        m_out.jump(continuation);
>+
>+        m_out.appendTo(slowCase, continuation);
>+        ValueFromBlock slowResult = m_out.anchor(
>+            vmCall(Int32, m_out.operation(operationMapHash), m_callFrame, value));
>+        m_out.jump(continuation);
>+
>+        m_out.appendTo(continuation, lastNext);
>+        setInt32(m_out.phi(Int32, fastResult, slowResult, nonEmptyStringHashResult));
>+    }
>+
>+    void compileGetMapBucket()
>+    {
>+        
>+        LBasicBlock loopStart = m_out.newBlock();
>+        LBasicBlock loopAround = m_out.newBlock();
>+        LBasicBlock slowPath = m_out.newBlock();
>+        LBasicBlock notPresentInTable = m_out.newBlock();
>+        LBasicBlock notEmptyValue = m_out.newBlock();
>+        LBasicBlock notDeletedValue = m_out.newBlock();
>+        LBasicBlock notBitEqual = m_out.newBlock();
>+        LBasicBlock bucketKeyNotCell = m_out.newBlock();
>+        LBasicBlock bucketKeyIsCell = m_out.newBlock();
>+        LBasicBlock bothAreCells = m_out.newBlock();
>+        LBasicBlock bucketKeyIsString = m_out.newBlock();
>+        LBasicBlock bucketKeyIsNumber = m_out.newBlock();
>+        LBasicBlock bothAreNumbers = m_out.newBlock();
>+        LBasicBlock bucketKeyIsInt32 = m_out.newBlock();
>+        LBasicBlock continuation = m_out.newBlock();
>+
>+        LValue map;
>+        if (m_node->child1().useKind() == MapObjectUse)
>+            map = lowMapObject(m_node->child1());
>+        else if (m_node->child1().useKind() == SetObjectUse)
>+            map = lowSetObject(m_node->child1());
>+        else
>+            RELEASE_ASSERT_NOT_REACHED();
>+
>+        LValue key = lowJSValue(m_node->child2());
>+        LValue hash = lowInt32(m_node->child3());
>+
>+        LValue hashMapImpl = m_out.loadPtr(map, m_node->child1().useKind() == MapObjectUse ? m_heaps.JSMap_hashMapImpl : m_heaps.JSSet_hashMapImpl);
>+        LValue buffer = m_out.loadPtr(hashMapImpl, m_heaps.HashMapImpl_buffer);
>+        LValue mask = m_out.sub(m_out.load32(hashMapImpl, m_heaps.HashMapImpl_capacity), m_out.int32One);
>+
>+        ValueFromBlock indexStart = m_out.anchor(hash);
>+        m_out.jump(loopStart);
>+
>+        LBasicBlock lastNext = m_out.appendTo(loopStart, notEmptyValue);
>+        LValue unmaskedIndex = m_out.phi(Int32, indexStart);
>+        LValue index = m_out.bitAnd(mask, unmaskedIndex);
>+        LValue hashMapBucket = m_out.load64(m_out.baseIndex(m_heaps.properties.atAnyNumber(), buffer, m_out.zeroExt(index, Int64), ScaleEight));
>+        ValueFromBlock bucketResult = m_out.anchor(hashMapBucket);
>+        m_out.branch(m_out.equal(hashMapBucket, m_out.constIntPtr(HashMapImpl<HashMapBucket<HashMapBucketDataKey>>::emptyValue())),
>+            unsure(notPresentInTable), unsure(notEmptyValue));
>+
>+        m_out.appendTo(notEmptyValue, notDeletedValue);
>+        m_out.branch(m_out.equal(hashMapBucket, m_out.constIntPtr(HashMapImpl<HashMapBucket<HashMapBucketDataKey>>::deletedValue())),
>+            unsure(loopAround), unsure(notDeletedValue));
>+
>+        m_out.appendTo(notDeletedValue, notBitEqual);
>+        LValue bucketKey = m_out.load64(hashMapBucket, m_heaps.HashMapBucket_key);
>+        // Perform Object.is()
>+        m_out.branch(m_out.equal(key, bucketKey),
>+            unsure(continuation), unsure(notBitEqual));
>+
>+        m_out.appendTo(notBitEqual, bucketKeyIsCell);
>+        m_out.branch(isCell(bucketKey),
>+            unsure(bucketKeyIsCell), unsure(bucketKeyNotCell));
>+
>+        m_out.appendTo(bucketKeyIsCell, bothAreCells);
>+        m_out.branch(isCell(key),
>+            unsure(bothAreCells), unsure(loopAround));
>+
>+        m_out.appendTo(bothAreCells, bucketKeyIsString);
>+        m_out.branch(isString(bucketKey),
>+            unsure(bucketKeyIsString), unsure(loopAround));
>+
>+        m_out.appendTo(bucketKeyIsString, bucketKeyNotCell);
>+        m_out.branch(isString(key),
>+            unsure(slowPath), unsure(loopAround));
>+
>+        m_out.appendTo(bucketKeyNotCell, bucketKeyIsNumber);
>+        m_out.branch(isNotNumber(bucketKey),
>+            unsure(loopAround), unsure(bucketKeyIsNumber));
>+
>+        m_out.appendTo(bucketKeyIsNumber, bothAreNumbers);
>+        m_out.branch(isNotNumber(key),
>+            unsure(loopAround), unsure(bothAreNumbers));
>+
>+        m_out.appendTo(bothAreNumbers, bucketKeyIsInt32);
>+        m_out.branch(isNotInt32(bucketKey),
>+            unsure(slowPath), unsure(bucketKeyIsInt32));
>+
>+        m_out.appendTo(bucketKeyIsInt32, loopAround);
>+        m_out.branch(isNotInt32(key),
>+            unsure(slowPath), unsure(loopAround));
>+
>+        m_out.appendTo(loopAround, slowPath);
>+        m_out.addIncomingToPhi(unmaskedIndex, m_out.anchor(m_out.add(index, m_out.int32One)));
>+        m_out.jump(loopStart);
>+
>+        m_out.appendTo(slowPath, notPresentInTable);
>+        ValueFromBlock slowPathResult = m_out.anchor(vmCall(pointerType(),
>+            m_out.operation(m_node->child1().useKind() == MapObjectUse ? operationJSMapFindBucket : operationJSSetFindBucket), m_callFrame, map, key, hash));
>+        m_out.jump(continuation);
>+
>+        m_out.appendTo(notPresentInTable, continuation);
>+        ValueFromBlock notPresentResult = m_out.anchor(m_out.constIntPtr(0));
>+        m_out.jump(continuation);
>+
>+        m_out.appendTo(continuation, lastNext);
>+        setMapBucket(m_out.phi(pointerType(), bucketResult, slowPathResult, notPresentResult));
>+    }
>+
>+    void compileLoadFromJSMapBucket()
>+    {
>+        LValue mapBucket = lowMapBucket(m_node->child1());
>+
>+        LBasicBlock continuation = m_out.newBlock();
>+        LBasicBlock hasBucket = m_out.newBlock();
>+
>+        ValueFromBlock noBucketResult = m_out.anchor(m_out.constInt64(JSValue::encode(jsUndefined())));
>+
>+        m_out.branch(m_out.equal(mapBucket, m_out.constIntPtr(0)),
>+            unsure(continuation), unsure(hasBucket));
>+
>+        LBasicBlock lastNext = m_out.appendTo(hasBucket, continuation);
>+        ValueFromBlock bucketResult = m_out.anchor(m_out.load64(mapBucket, m_heaps.HashMapBucket_value));
>+        m_out.jump(continuation);
>+
>+        m_out.appendTo(continuation, lastNext);
>+        setJSValue(m_out.phi(Int64, noBucketResult, bucketResult));
>+    }
>+
>+    void compileIsNonEmptyMapBucket()
>+    {
>+        LValue bucket = lowMapBucket(m_node->child1());
>+        LValue result = m_out.notEqual(bucket, m_out.constIntPtr(0));
>+        setBoolean(result);
>+    }
>+
>     void compileIsObjectOrNull()
>     {
>         JSGlobalObject* globalObject = m_graph.globalObjectFor(m_node->origin.semantic);
>@@ -9928,6 +10163,20 @@ private:
>         speculateRegExpObject(edge, result);
>         return result;
>     }
>+
>+    LValue lowMapObject(Edge edge)
>+    {
>+        LValue result = lowCell(edge);
>+        speculateMapObject(edge, result);
>+        return result;
>+    }
>+
>+    LValue lowSetObject(Edge edge)
>+    {
>+        LValue result = lowCell(edge);
>+        speculateSetObject(edge, result);
>+        return result;
>+    }
>     
>     LValue lowString(Edge edge, OperandSpeculationMode mode = AutomaticOperandSpeculation)
>     {
>@@ -10051,6 +10300,17 @@ private:
>         setStorage(edge.node(), result);
>         return result;
>     }
>+
>+    LValue lowMapBucket(Edge edge)
>+    {
>+        LoweredNodeValue value = m_mapBucketValues.get(edge.node());
>+        if (isValid(value))
>+            return value.value();
>+        
>+        LValue result = lowCell(edge);
>+        setStorage(edge.node(), result);
>+        return result;
>+    }
>     
>     LValue strictInt52ToInt32(Edge edge, LValue value)
>     {
>@@ -10354,6 +10614,12 @@ private:
>         case RegExpObjectUse:
>             speculateRegExpObject(edge);
>             break;
>+        case MapObjectUse:
>+            speculateMapObject(edge);
>+            break;
>+        case SetObjectUse:
>+            speculateSetObject(edge);
>+            break;
>         case StringUse:
>             speculateString(edge);
>             break;
>@@ -10682,6 +10948,28 @@ private:
>     {
>         speculateRegExpObject(edge, lowCell(edge));
>     }
>+
>+    void speculateMapObject(Edge edge, LValue cell)
>+    {
>+        FTL_TYPE_CHECK(
>+            jsValueValue(cell), edge, SpecMapObject, isNotType(cell, JSMapType));
>+    }
>+
>+    void speculateMapObject(Edge edge)
>+    {
>+        speculateMapObject(edge, lowCell(edge));
>+    }
>+
>+    void speculateSetObject(Edge edge, LValue cell)
>+    {
>+        FTL_TYPE_CHECK(
>+            jsValueValue(cell), edge, SpecSetObject, isNotType(cell, JSSetType));
>+    }
>+
>+    void speculateSetObject(Edge edge)
>+    {
>+        speculateSetObject(edge, lowCell(edge));
>+    }
>     
>     void speculateString(Edge edge, LValue cell)
>     {
>@@ -11450,6 +11738,10 @@ private:
>     {
>         m_storageValues.set(node, LoweredNodeValue(value, m_highBlock));
>     }
>+    void setMapBucket(Node* node, LValue value)
>+    {
>+        m_mapBucketValues.set(node, LoweredNodeValue(value, m_highBlock));
>+    }
>     void setDouble(Node* node, LValue value)
>     {
>         m_doubleValues.set(node, LoweredNodeValue(value, m_highBlock));
>@@ -11483,6 +11775,10 @@ private:
>     {
>         setStorage(m_node, value);
>     }
>+    void setMapBucket(LValue value)
>+    {
>+        setMapBucket(m_node, value);
>+    }
>     void setDouble(LValue value)
>     {
>         setDouble(m_node, value);
>@@ -11666,6 +11962,7 @@ private:
>     HashMap<Node*, LoweredNodeValue> m_jsValueValues;
>     HashMap<Node*, LoweredNodeValue> m_booleanValues;
>     HashMap<Node*, LoweredNodeValue> m_storageValues;
>+    HashMap<Node*, LoweredNodeValue> m_mapBucketValues;
>     HashMap<Node*, LoweredNodeValue> m_doubleValues;
>     
>     // This is a bit of a hack. It prevents B3 from having to do CSE on loading of arguments.
>Index: Source/JavaScriptCore/jit/AssemblyHelpers.cpp
>===================================================================
>--- Source/JavaScriptCore/jit/AssemblyHelpers.cpp	(revision 205305)
>+++ Source/JavaScriptCore/jit/AssemblyHelpers.cpp	(working copy)
>@@ -626,6 +626,52 @@ void AssemblyHelpers::emitDumbVirtualCal
>         });
> }
> 
>+#if USE(JSVALUE64)
>+void AssemblyHelpers::WangsInt64Hash(GPRReg inputAndResult, GPRReg scratch)
>+{
>+    GPRReg input = inputAndResult;
>+    // key += ~(key << 32);
>+    move(input, scratch);
>+    lshift64(TrustedImm32(32), scratch);
>+    not64(scratch);
>+    add64(scratch, input);
>+    // key ^= (key >> 22);
>+    move(input, scratch);
>+    urshift64(TrustedImm32(22), scratch);
>+    xor64(scratch, input);
>+    // key += ~(key << 13);
>+    move(input, scratch);
>+    lshift64(TrustedImm32(13), scratch);
>+    not64(scratch);
>+    add64(scratch, input);
>+    // key ^= (key >> 8);
>+    move(input, scratch);
>+    urshift64(TrustedImm32(8), scratch);
>+    xor64(scratch, input);
>+    // key += (key << 3);
>+    move(input, scratch);
>+    lshift64(TrustedImm32(3), scratch);
>+    add64(scratch, input);
>+    // key ^= (key >> 15);
>+    move(input, scratch);
>+    urshift64(TrustedImm32(15), scratch);
>+    xor64(scratch, input);
>+    // key += ~(key << 27);
>+    move(input, scratch);
>+    lshift64(TrustedImm32(27), scratch);
>+    not64(scratch);
>+    add64(scratch, input);
>+    // key ^= (key >> 31);
>+    move(input, scratch);
>+    urshift64(TrustedImm32(31), scratch);
>+    xor64(scratch, input);
>+
>+    // return static_cast<unsigned>(result)
>+    void* mask = bitwise_cast<void*>(static_cast<uintptr_t>(UINT_MAX));
>+    and64(TrustedImmPtr(mask), inputAndResult);
>+}
>+#endif // USE(JSVALUE64)
>+
> } // namespace JSC
> 
> #endif // ENABLE(JIT)
>Index: Source/JavaScriptCore/jit/AssemblyHelpers.h
>===================================================================
>--- Source/JavaScriptCore/jit/AssemblyHelpers.h	(revision 205305)
>+++ Source/JavaScriptCore/jit/AssemblyHelpers.h	(working copy)
>@@ -61,7 +61,7 @@ public:
>             ASSERT(m_baselineCodeBlock->jitType() == JITCode::None || JITCode::isBaselineCode(m_baselineCodeBlock->jitType()));
>         }
>     }
>-    
>+
>     CodeBlock* codeBlock() { return m_codeBlock; }
>     VM* vm() { return m_vm; }
>     AssemblerType_T& assembler() { return m_assembler; }
>@@ -1489,6 +1489,10 @@ public:
>         emitAllocateJSObject<ClassType>(resultGPR, TrustedImmPtr(structure), TrustedImmPtr(0), scratchGPR1, scratchGPR2, slowPath);
>         storePtr(TrustedImmPtr(structure->classInfo()), Address(resultGPR, JSDestructibleObject::classInfoOffset()));
>     }
>+
>+#if USE(JSVALUE64)
>+    void WangsInt64Hash(GPRReg inputAndResult, GPRReg scratch);
>+#endif
>     
> protected:
>     VM* m_vm;
>Index: Source/JavaScriptCore/jit/JITOperations.h
>===================================================================
>--- Source/JavaScriptCore/jit/JITOperations.h	(revision 205305)
>+++ Source/JavaScriptCore/jit/JITOperations.h	(working copy)
>@@ -194,6 +194,7 @@ typedef JSCell* (JIT_OPERATION *C_JITOpe
> typedef JSCell* (JIT_OPERATION *C_JITOperation_EStZZ)(ExecState*, Structure*, int32_t, int32_t);
> typedef JSCell* (JIT_OPERATION *C_JITOperation_EZ)(ExecState*, int32_t);
> typedef JSCell* (JIT_OPERATION *C_JITOperation_EJscI)(ExecState*, JSScope*, UniquedStringImpl*);
>+typedef JSCell* (JIT_OPERATION *C_JITOperation_ECJZ)(ExecState*, JSCell*, EncodedJSValue, int32_t);
> typedef double (JIT_OPERATION *D_JITOperation_D)(double);
> typedef double (JIT_OPERATION *D_JITOperation_G)(JSGlobalObject*);
> typedef double (JIT_OPERATION *D_JITOperation_DD)(double, double);
>Index: Source/JavaScriptCore/parser/ModuleAnalyzer.cpp
>===================================================================
>--- Source/JavaScriptCore/parser/ModuleAnalyzer.cpp	(revision 205305)
>+++ Source/JavaScriptCore/parser/ModuleAnalyzer.cpp	(working copy)
>@@ -39,7 +39,7 @@ namespace JSC {
> 
> ModuleAnalyzer::ModuleAnalyzer(ExecState* exec, const Identifier& moduleKey, const SourceCode& sourceCode, const VariableEnvironment& declaredVariables, const VariableEnvironment& lexicalVariables)
>     : m_vm(&exec->vm())
>-    , m_moduleRecord(exec->vm(), JSModuleRecord::create(exec->vm(), exec->lexicalGlobalObject()->moduleRecordStructure(), moduleKey, sourceCode, declaredVariables, lexicalVariables))
>+    , m_moduleRecord(exec->vm(), JSModuleRecord::create(exec, exec->vm(), exec->lexicalGlobalObject()->moduleRecordStructure(), moduleKey, sourceCode, declaredVariables, lexicalVariables))
> {
> }
> 
>Index: Source/JavaScriptCore/runtime/HashMapImpl.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/HashMapImpl.cpp	(nonexistent)
>+++ Source/JavaScriptCore/runtime/HashMapImpl.cpp	(working copy)
>@@ -0,0 +1,94 @@
>+/*
>+ * Copyright (C) 2016 Apple Inc. All rights reserved.
>+ *
>+ * Redistribution and use in source and binary forms, with or without
>+ * modification, are permitted provided that the following conditions
>+ * are met:
>+ * 1. Redistributions of source code must retain the above copyright
>+ *    notice, this list of conditions and the following disclaimer.
>+ * 2. Redistributions in binary form must reproduce the above copyright
>+ *    notice, this list of conditions and the following disclaimer in the
>+ *    documentation and/or other materials provided with the distribution.
>+ *
>+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
>+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
>+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
>+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
>+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
>+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
>+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
>+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
>+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
>+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
>+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
>+ */
>+
>+#include "config.h"
>+#include "HashMapImpl.h"
>+
>+#include "CopiedBlockInlines.h"
>+#include "CopyVisitorInlines.h"
>+#include "SlotVisitorInlines.h"
>+
>+namespace JSC {
>+
>+template<>
>+const ClassInfo HashMapBucket<HashMapBucketDataKey>::s_info =
>+    { "HashMapBucket", nullptr, 0, CREATE_METHOD_TABLE(HashMapBucket<HashMapBucketDataKey>) };
>+
>+template<>
>+const ClassInfo HashMapBucket<HashMapBucketDataKeyValue>::s_info =
>+    { "HashMapBucket", nullptr, 0, CREATE_METHOD_TABLE(HashMapBucket<HashMapBucketDataKeyValue>) };
>+
>+template <typename Data>
>+void HashMapBucket<Data>::visitChildren(JSCell* cell, SlotVisitor& visitor)
>+{
>+    HashMapBucket* thisObject = jsCast<HashMapBucket*>(cell);
>+    ASSERT_GC_OBJECT_INHERITS(thisObject, info());
>+    Base::visitChildren(thisObject, visitor);
>+
>+    visitor.append(&thisObject->m_next);
>+    visitor.append(&thisObject->m_prev);
>+
>+    static_assert(sizeof(Data) % sizeof(WriteBarrier<Unknown>) == 0, "We assume that these are filled with WriteBarrier<Unknown> members only.");
>+    visitor.appendValues(bitwise_cast<WriteBarrier<Unknown>*>(&thisObject->m_data), sizeof(Data) / sizeof(WriteBarrier<Unknown>));
>+}
>+
>+template<>
>+const ClassInfo HashMapImpl<HashMapBucket<HashMapBucketDataKey>>::s_info =
>+    { "HashMapImpl", nullptr, 0, CREATE_METHOD_TABLE(HashMapImpl<HashMapBucket<HashMapBucketDataKey>>) };
>+
>+template<>
>+const ClassInfo HashMapImpl<HashMapBucket<HashMapBucketDataKeyValue>>::s_info =
>+    { "HashMapImpl", nullptr, 0, CREATE_METHOD_TABLE(HashMapImpl<HashMapBucket<HashMapBucketDataKeyValue>>) };
>+
>+template <typename HashMapBucket>
>+void HashMapImpl<HashMapBucket>::visitChildren(JSCell* cell, SlotVisitor& visitor)
>+{
>+    HashMapImpl* thisObject = jsCast<HashMapImpl*>(cell);
>+    ASSERT_GC_OBJECT_INHERITS(thisObject, info());
>+    Base::visitChildren(thisObject, visitor);
>+
>+    visitor.append(&thisObject->m_head);
>+    visitor.append(&thisObject->m_tail);
>+
>+    visitor.copyLater(thisObject, MapBackingStoreCopyToken, thisObject->m_buffer.get(), thisObject->bufferSizeInBytes());
>+}
>+
>+template <typename HashMapBucket>
>+void HashMapImpl<HashMapBucket>::copyBackingStore(JSCell* cell, CopyVisitor& visitor, CopyToken token)
>+{
>+    Base::copyBackingStore(cell, visitor, token);
>+
>+    HashMapImpl* thisObject = jsCast<HashMapImpl*>(cell);
>+    if (token == MapBackingStoreCopyToken && visitor.checkIfShouldCopy(thisObject->m_buffer.get())) {
>+        HashMapBufferType* oldBuffer = thisObject->m_buffer.get();
>+        size_t bufferSizeInBytes = thisObject->bufferSizeInBytes();
>+        HashMapBufferType* newBuffer = static_cast<HashMapBufferType*>(visitor.allocateNewSpace(bufferSizeInBytes));
>+        memcpy(newBuffer, oldBuffer, bufferSizeInBytes);
>+        thisObject->m_buffer.setWithoutBarrier(newBuffer);
>+        visitor.didCopy(oldBuffer, bufferSizeInBytes);
>+    }
>+}
>+
>+} // namespace JSC
>Index: Source/JavaScriptCore/runtime/HashMapImpl.h
>===================================================================
>--- Source/JavaScriptCore/runtime/HashMapImpl.h	(nonexistent)
>+++ Source/JavaScriptCore/runtime/HashMapImpl.h	(working copy)
>@@ -0,0 +1,532 @@
>+/*
>+ * Copyright (C) 2016 Apple Inc. All rights reserved.
>+ *
>+ * Redistribution and use in source and binary forms, with or without
>+ * modification, are permitted provided that the following conditions
>+ * are met:
>+ * 1. Redistributions of source code must retain the above copyright
>+ *    notice, this list of conditions and the following disclaimer.
>+ * 2. Redistributions in binary form must reproduce the above copyright
>+ *    notice, this list of conditions and the following disclaimer in the
>+ *    documentation and/or other materials provided with the distribution.
>+ *
>+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
>+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
>+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
>+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
>+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
>+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
>+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
>+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
>+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
>+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
>+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
>+ */
>+
>+#pragma once
>+
>+#include "JSCJSValueInlines.h"
>+#include "JSObject.h"
>+
>+namespace JSC {
>+
>+struct HashMapBucketDataKey {
>+    WriteBarrier<Unknown> key;
>+};
>+
>+struct HashMapBucketDataKeyValue {
>+    WriteBarrier<Unknown> key;
>+    WriteBarrier<Unknown> value;
>+};
>+
>+template <typename Data>
>+class HashMapBucket : public JSCell {
>+    typedef JSCell Base;
>+
>+    template <typename T = Data>
>+    static typename std::enable_if<std::is_same<T, HashMapBucketDataKey>::value, Structure*>::type selectStructure(VM& vm)
>+    {
>+        return vm.hashMapBucketSetStructure.get();
>+    }
>+
>+    template <typename T = Data>
>+    static typename std::enable_if<std::is_same<T, HashMapBucketDataKeyValue>::value, Structure*>::type selectStructure(VM& vm)
>+    {
>+        return vm.hashMapBucketMapStructure.get();
>+    }
>+
>+public:
>+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
>+    {
>+        return Structure::create(vm, globalObject, prototype, TypeInfo(CellType, StructureFlags), info());
>+    }
>+
>+    static HashMapBucket* create(VM& vm)
>+    {
>+        HashMapBucket* bucket = new (NotNull, allocateCell<HashMapBucket>(vm.heap)) HashMapBucket(vm, selectStructure(vm));
>+        bucket->finishCreation(vm);
>+        ASSERT(!bucket->next());
>+        ASSERT(!bucket->prev());
>+        return bucket;
>+    }
>+
>+    DECLARE_EXPORT_INFO;
>+
>+    HashMapBucket(VM& vm, Structure* structure)
>+        : Base(vm, structure)
>+    { }
>+
>+    ALWAYS_INLINE void setNext(VM& vm, HashMapBucket* bucket)
>+    {
>+        m_next.set(vm, this, bucket);
>+    }
>+    ALWAYS_INLINE void setPrev(VM& vm, HashMapBucket* bucket)
>+    {
>+        m_prev.set(vm, this, bucket);
>+    }
>+
>+    ALWAYS_INLINE void setKey(VM& vm, JSValue key)
>+    {
>+        m_data.key.set(vm, this, key);
>+    }
>+
>+    template <typename T = Data>
>+    ALWAYS_INLINE typename std::enable_if<std::is_same<T, HashMapBucketDataKeyValue>::value>::type setValue(VM& vm, JSValue value)
>+    {
>+        m_data.value.set(vm, this, value);
>+    }
>+    template <typename T = Data>
>+    ALWAYS_INLINE typename std::enable_if<std::is_same<T, HashMapBucketDataKey>::value>::type setValue(VM&, JSValue) { }
>+
>+    ALWAYS_INLINE JSValue key() const { return m_data.key.get(); }
>+
>+    template <typename T = Data>
>+    ALWAYS_INLINE typename std::enable_if<std::is_same<T, HashMapBucketDataKeyValue>::value, JSValue>::type value() const
>+    {
>+        return m_data.value.get();
>+    }
>+
>+    static void visitChildren(JSCell*, SlotVisitor&);
>+
>+    ALWAYS_INLINE HashMapBucket* next() const { return m_next.get(); }
>+    ALWAYS_INLINE HashMapBucket* prev() const { return m_prev.get(); }
>+
>+    ALWAYS_INLINE bool deleted() const { return m_deleted; }
>+    ALWAYS_INLINE void setDeleted(bool deleted) { m_deleted = deleted; }
>+
>+    static ptrdiff_t offsetOfKey()
>+    {
>+        return OBJECT_OFFSETOF(HashMapBucket, m_data) + OBJECT_OFFSETOF(Data, key);
>+    }
>+
>+    template <typename T = Data>
>+    static typename std::enable_if<std::is_same<T, HashMapBucketDataKeyValue>::value, ptrdiff_t>::type offsetOfValue()
>+    {
>+        return OBJECT_OFFSETOF(HashMapBucket, m_data) + OBJECT_OFFSETOF(Data, value);
>+    }
>+
>+private:
>+    Data m_data;
>+    WriteBarrier<HashMapBucket> m_next;
>+    WriteBarrier<HashMapBucket> m_prev;
>+    bool m_deleted { false };
>+};
>+
>+template <typename BucketType>
>+class HashMapBuffer {
>+public:
>+    HashMapBuffer() = delete;
>+
>+    static size_t allocationSize(uint32_t capacity)
>+    {
>+        return capacity * sizeof(BucketType*);
>+    }
>+
>+    ALWAYS_INLINE BucketType** buffer() const
>+    {
>+        return bitwise_cast<BucketType**>(this);
>+    }
>+
>+    static HashMapBuffer* create(ExecState* exec, VM& vm, JSCell* owner, uint32_t capacity)
>+    {
>+        auto scope = DECLARE_THROW_SCOPE(vm);
>+        size_t allocationSize = HashMapBuffer::allocationSize(capacity);
>+        void* data = nullptr;
>+        DeferGCForAWhile defer(vm.heap);
>+        if (!vm.heap.tryAllocateStorage(owner, allocationSize, &data)) {
>+            throwOutOfMemoryError(exec, scope);
>+            return nullptr;
>+        }
>+
>+        HashMapBuffer* buffer = static_cast<HashMapBuffer*>(data);
>+        memset(buffer, -1, allocationSize);
>+        return buffer;
>+    }
>+
>+};
>+
>+ALWAYS_INLINE static bool areKeysEqual(ExecState* exec, JSValue a, JSValue b)
>+{
>+    // We want +0 and -0 to be compared to true here. sameValue() itself doesn't
>+    // guarantee that, however, we normalize all keys before comparing and storing
>+    // them in the map. The normalization will convert -0.0 and 0.0 to the integer
>+    // representation for 0.
>+    return sameValue(exec, a, b);
>+}
>+
>+ALWAYS_INLINE JSValue normalizeMapKey(JSValue key)
>+{
>+    if (!key.isNumber())
>+        return key;
>+
>+    if (key.isInt32())
>+        return key;
>+
>+    double d = key.asDouble();
>+    if (std::isnan(d))
>+        return key;
>+
>+    int i = static_cast<int>(d);
>+    if (i == d) {
>+        // When a key is -0, we convert it to positive zero.
>+        // When a key is the double representation for an integer, we convert it to an integer.
>+        return jsNumber(i);
>+    }
>+    // This means key is definitely not negative zero, and it's definitely not a double representation of an integer. 
>+    return key;
>+}
>+
>+ALWAYS_INLINE uint32_t jsMapHash(ExecState* exec, VM& vm, JSValue value)
>+{
>+    ASSERT_WITH_MESSAGE(normalizeMapKey(value) == value, "We expect normalized values flowing into this function.");
>+
>+    auto scope = DECLARE_THROW_SCOPE(vm);
>+
>+    if (value.isDouble()) {
>+        double d = value.asDouble();
>+        if (!std::isnan(d)) {
>+            int i = static_cast<int>(d);
>+            if (i == d)
>+                value = jsNumber(i);
>+        }
>+    }
>+    if (value.isString()) {
>+        JSString* string = asString(value);
>+        const String& wtfString = string->value(exec);
>+        if (UNLIKELY(scope.exception()))
>+            return UINT_MAX;
>+        return wtfString.impl()->hash();
>+    }
>+
>+    auto WangsInt64Hash = [] (uint64_t key) -> uint32_t {
>+        key += ~(key << 32);
>+        key ^= (key >> 22);
>+        key += ~(key << 13);
>+        key ^= (key >> 8);
>+        key += (key << 3);
>+        key ^= (key >> 15);
>+        key += ~(key << 27);
>+        key ^= (key >> 31);
>+        return static_cast<unsigned>(key);
>+    };
>+    uint64_t rawValue = JSValue::encode(value);
>+    return WangsInt64Hash(rawValue);
>+}
>+
>+template <typename HashMapBucketType>
>+class HashMapImpl : public JSCell {
>+    typedef JSCell Base;
>+    typedef HashMapBuffer<HashMapBucketType> HashMapBufferType;
>+
>+    template <typename T = HashMapBucketType>
>+    static typename std::enable_if<std::is_same<T, HashMapBucket<HashMapBucketDataKey>>::value, Structure*>::type selectStructure(VM& vm)
>+    {
>+        return vm.hashMapImplSetStructure.get();
>+    }
>+
>+    template <typename T = HashMapBucketType>
>+    static typename std::enable_if<std::is_same<T, HashMapBucket<HashMapBucketDataKeyValue>>::value, Structure*>::type selectStructure(VM& vm)
>+    {
>+        return vm.hashMapImplMapStructure.get();
>+    }
>+
>+public:
>+    DECLARE_EXPORT_INFO;
>+
>+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
>+    {
>+        return Structure::create(vm, globalObject, prototype, TypeInfo(CellType, StructureFlags), info());
>+    }
>+
>+    static HashMapImpl* create(ExecState* exec, VM& vm)
>+    {
>+        ASSERT_WITH_MESSAGE(HashMapBucket<HashMapBucketDataKey>::offsetOfKey() == HashMapBucket<HashMapBucketDataKeyValue>::offsetOfKey(), "We assume this to be true in the DFG and FTL JIT.");
>+
>+        HashMapImpl* impl = new (NotNull, allocateCell<HashMapImpl>(vm.heap)) HashMapImpl(vm, selectStructure(vm));
>+        impl->finishCreation(exec, vm);
>+        return impl;
>+    }
>+
>+    static void visitChildren(JSCell*, SlotVisitor&);
>+    static void copyBackingStore(JSCell*, CopyVisitor&, CopyToken);
>+
>+    HashMapImpl(VM& vm, Structure* structure)
>+        : Base(vm, structure)
>+        , m_size(0)
>+        , m_deleteCount(0)
>+        , m_capacity(4)
>+    {
>+    }
>+
>+    ALWAYS_INLINE HashMapBucketType** buffer() const
>+    {
>+        return m_buffer.get()->buffer();
>+    }
>+
>+    void finishCreation(ExecState* exec, VM& vm)
>+    {
>+        auto scope = DECLARE_THROW_SCOPE(vm);
>+        Base::finishCreation(vm);
>+
>+        makeAndSetNewBuffer(exec, vm);
>+        if (UNLIKELY(scope.exception()))
>+            return;
>+
>+        m_head.set(vm, this, HashMapBucketType::create(vm));
>+        m_tail.set(vm, this, HashMapBucketType::create(vm));
>+
>+        m_head->setNext(vm, m_tail.get());
>+        m_tail->setPrev(vm, m_head.get());
>+        m_head->setDeleted(true);
>+        m_tail->setDeleted(true);
>+
>+    }
>+
>+    static HashMapBucketType* emptyValue()
>+    {
>+        return bitwise_cast<HashMapBucketType*>(static_cast<uintptr_t>(-1));
>+    }
>+
>+    static ALWAYS_INLINE bool isEmpty(HashMapBucketType* bucket)
>+    {
>+        return bucket == emptyValue();
>+    }
>+
>+    static HashMapBucketType* deletedValue()
>+    {
>+        return bitwise_cast<HashMapBucketType*>(static_cast<uintptr_t>(-3));
>+    }
>+
>+    static ALWAYS_INLINE bool isDeleted(HashMapBucketType* bucket)
>+    {
>+        return bucket == deletedValue();
>+    }
>+
>+    ALWAYS_INLINE HashMapBucketType** findBucket(ExecState* exec, JSValue key)
>+    {
>+        VM& vm = exec->vm();
>+        uint32_t hash = jsMapHash(exec, vm, key);
>+        auto scope = DECLARE_THROW_SCOPE(vm);
>+        if (UNLIKELY(scope.exception()))
>+            return nullptr;
>+        return findBucket(exec, key, hash);
>+    }
>+
>+    ALWAYS_INLINE HashMapBucketType** findBucket(ExecState* exec, JSValue key, uint32_t hash)
>+    {
>+        key = normalizeMapKey(key);
>+        return findBucketAlreadyHashedAndNormalized(exec, key, hash);
>+    }
>+
>+    ALWAYS_INLINE JSValue get(ExecState* exec, JSValue key)
>+    {
>+        if (HashMapBucketType** bucket = findBucket(exec, key))
>+            return (*bucket)->value();
>+        return jsUndefined();
>+    }
>+
>+    ALWAYS_INLINE bool has(ExecState* exec, JSValue key)
>+    {
>+        return !!findBucket(exec, key);
>+    }
>+
>+    ALWAYS_INLINE void add(ExecState* exec, JSValue key, JSValue value = JSValue())
>+    {
>+        key = normalizeMapKey(key);
>+
>+        VM& vm = exec->vm();
>+        auto scope = DECLARE_THROW_SCOPE(vm);
>+
>+        const uint32_t mask = m_capacity - 1;
>+        uint32_t index = jsMapHash(exec, vm, key) & mask;
>+        if (UNLIKELY(scope.exception()))
>+            return;
>+        HashMapBucketType** buffer = this->buffer();
>+        HashMapBucketType* bucket = buffer[index];
>+        while (!isEmpty(bucket)) {
>+            if (!isDeleted(bucket) && areKeysEqual(exec, key, bucket->key())) {
>+                bucket->setValue(vm, value);
>+                return;
>+            }
>+            index = (index + 1) & mask;
>+            bucket = buffer[index];
>+        }
>+
>+        HashMapBucketType* newEntry = m_tail.get();
>+        buffer[index] = newEntry;
>+        newEntry->setKey(vm, key);
>+        newEntry->setValue(vm, value);
>+        newEntry->setDeleted(false);
>+        HashMapBucketType* newTail = HashMapBucketType::create(vm);
>+        m_tail.set(vm, this, newTail);
>+        newTail->setPrev(vm, newEntry);
>+        newTail->setDeleted(true);
>+        newEntry->setNext(vm, newTail);
>+        uint32_t newSize = ++m_size;
>+        if (2*newSize > m_capacity)
>+            rehash(exec);
>+    }
>+
>+    ALWAYS_INLINE bool remove(ExecState* exec, JSValue key)
>+    {
>+        HashMapBucketType** bucket = findBucket(exec, key);
>+        if (!bucket)
>+            return false;
>+
>+        VM& vm = exec->vm();
>+        HashMapBucketType* impl = *bucket;
>+        impl->next()->setPrev(vm, impl->prev());
>+        impl->prev()->setNext(vm, impl->next());
>+        impl->setDeleted(true);
>+
>+        *bucket = deletedValue();
>+
>+        m_deleteCount++;
>+
>+        return true;
>+    }
>+
>+    ALWAYS_INLINE uint32_t size() const
>+    {
>+        RELEASE_ASSERT(m_size >= m_deleteCount);
>+        return m_size - m_deleteCount;
>+    }
>+
>+    ALWAYS_INLINE void clear(ExecState* exec)
>+    {
>+        VM& vm = exec->vm();
>+        m_size = 0;
>+        m_deleteCount = 0;
>+        HashMapBucketType* head = m_head.get();
>+        HashMapBucketType* bucket = m_head->next();
>+        HashMapBucketType* tail = m_tail.get();
>+        while (bucket != tail) {
>+            HashMapBucketType* next = bucket->next();
>+            // We restart each iterator by pointing it to the head of the list.
>+            bucket->setNext(vm, head);
>+            bucket = next;
>+        }
>+        m_head->setNext(vm, m_tail.get());
>+        m_tail->setPrev(vm, m_head.get());
>+        m_capacity = 4;
>+        makeAndSetNewBuffer(exec, vm);
>+    }
>+
>+    ALWAYS_INLINE size_t bufferSizeInBytes() const
>+    {
>+        return m_capacity * sizeof(HashMapBucketType*);
>+    }
>+
>+    static ptrdiff_t offsetOfBuffer()
>+    {
>+        return OBJECT_OFFSETOF(HashMapImpl<HashMapBucketType>, m_buffer);
>+    }
>+
>+    static ptrdiff_t offsetOfCapacity()
>+    {
>+        return OBJECT_OFFSETOF(HashMapImpl<HashMapBucketType>, m_capacity);
>+    }
>+
>+    HashMapBucketType* head() { return m_head.get(); }
>+    HashMapBucketType* tail() { return m_tail.get(); }
>+
>+    size_t approximateSize() const
>+    {
>+        size_t size = sizeof(HashMapImpl);
>+        size += bufferSizeInBytes();
>+        size += 2 * sizeof(HashMapBucketType); // Head and tail members.
>+        size += (m_deleteCount + m_size) * sizeof(HashMapBucketType); // Number of members on the list.
>+        return size;
>+    }
>+
>+private:
>+    ALWAYS_INLINE HashMapBucketType** findBucketAlreadyHashedAndNormalized(ExecState* exec, JSValue key, uint32_t hash)
>+    {
>+        const uint32_t mask = m_capacity - 1;
>+        uint32_t index = hash & mask;
>+        HashMapBucketType** buffer = this->buffer();
>+        HashMapBucketType* bucket = buffer[index];
>+
>+        while (!isEmpty(bucket)) {
>+            if (!isDeleted(bucket) && areKeysEqual(exec, key, bucket->key()))
>+                return buffer + index;
>+            index = (index + 1) & mask;
>+            bucket = buffer[index];
>+        }
>+        return nullptr;
>+    }
>+
>+    void rehash(ExecState* exec)
>+    {
>+        VM& vm = exec->vm();
>+        auto scope = DECLARE_THROW_SCOPE(vm);
>+
>+        m_capacity = m_capacity * 2;
>+        makeAndSetNewBuffer(exec, vm);
>+        if (UNLIKELY(scope.exception()))
>+            return;
>+
>+        HashMapBucketType* iter = m_head->next();
>+        HashMapBucketType* end = m_tail.get();
>+        const uint32_t mask = m_capacity - 1;
>+        RELEASE_ASSERT(!(m_capacity & (m_capacity - 1)));
>+        HashMapBucketType** buffer = this->buffer();
>+        while (iter != end) {
>+            uint32_t index = jsMapHash(exec, vm, iter->key()) & mask;
>+            ASSERT_WITH_MESSAGE(!scope.exception(), "All keys should already be hashed before, so this should not throw because it won't resolve ropes.");
>+            {
>+                HashMapBucketType* bucket = buffer[index];
>+                while (!isEmpty(bucket)) {
>+                    index = (index + 1) & mask;
>+                    bucket = buffer[index];
>+                }
>+            }
>+            buffer[index] = iter;
>+            iter = iter->next();
>+        }
>+    }
>+
>+    void makeAndSetNewBuffer(ExecState* exec, VM& vm)
>+    {
>+        ASSERT(!(m_capacity & (m_capacity - 1)));
>+
>+        HashMapBufferType* buffer = HashMapBufferType::create(exec, vm, this, m_capacity);
>+        if (UNLIKELY(!buffer))
>+            return;
>+
>+        m_buffer.set(vm, this, buffer);
>+        if (!ASSERT_DISABLED) {
>+            for (unsigned i = 0; i < m_capacity; i++)
>+                ASSERT(isEmpty(this->buffer()[i]));
>+        }
>+    }
>+
>+    WriteBarrier<HashMapBucketType> m_head;
>+    WriteBarrier<HashMapBucketType> m_tail;
>+    CopyBarrier<HashMapBufferType> m_buffer;
>+    uint32_t m_size;
>+    uint32_t m_deleteCount;
>+    uint32_t m_capacity;
>+};
>+
>+} // namespace JSC
>Index: Source/JavaScriptCore/runtime/Intrinsic.h
>===================================================================
>--- Source/JavaScriptCore/runtime/Intrinsic.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/Intrinsic.h	(working copy)
>@@ -62,6 +62,9 @@ enum JS_EXPORT_PRIVATE Intrinsic {
>     IsRegExpObjectIntrinsic,
>     IsTypedArrayViewIntrinsic,
>     BoundThisNoArgsFunctionCallIntrinsic,
>+    JSMapGetIntrinsic,
>+    JSMapHasIntrinsic,
>+    JSSetHasIntrinsic,
> 
>     // Getter intrinsics.
>     TypedArrayLengthIntrinsic,
>Index: Source/JavaScriptCore/runtime/JSCJSValue.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSCJSValue.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSCJSValue.h	(working copy)
>@@ -606,6 +606,9 @@ inline bool operator!=(const JSCell* a, 
> 
> bool isThisValueAltered(const PutPropertySlot&, JSObject* baseObject);
> 
>+// See section 7.2.9: https://tc39.github.io/ecma262/#sec-samevalue
>+bool sameValue(ExecState*, JSValue a, JSValue b);
>+
> } // namespace JSC
> 
> #endif // JSCJSValue_h
>Index: Source/JavaScriptCore/runtime/JSCJSValueInlines.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSCJSValueInlines.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSCJSValueInlines.h	(working copy)
>@@ -1058,6 +1058,22 @@ ALWAYS_INLINE bool isThisValueAltered(co
>     return true;
> }
> 
>+// See section 7.2.9: https://tc39.github.io/ecma262/#sec-samevalue
>+ALWAYS_INLINE bool sameValue(ExecState* exec, JSValue a, JSValue b)
>+{
>+    if (!a.isNumber())
>+        return JSValue::strictEqual(exec, a, b);
>+    if (!b.isNumber())
>+        return false;
>+    double x = a.asNumber();
>+    double y = b.asNumber();
>+    bool xIsNaN = std::isnan(x);
>+    bool yIsNaN = std::isnan(y);
>+    if (xIsNaN || yIsNaN)
>+        return xIsNaN && yIsNaN;
>+    return bitwise_cast<uint64_t>(x) == bitwise_cast<uint64_t>(y);
>+}
>+
> } // namespace JSC
> 
> #endif // JSValueInlines_h
>Index: Source/JavaScriptCore/runtime/JSGlobalObject.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSGlobalObject.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSGlobalObject.cpp	(working copy)
>@@ -641,7 +641,7 @@ putDirectWithoutTransition(vm, vm.proper
>     putDirectWithoutTransition(vm, vm.propertyNames->Reflect, reflectObject, DontEnum);
> 
>     m_moduleLoaderStructure.set(vm, this, JSModuleLoader::createStructure(vm, this, m_moduleLoaderPrototype.get()));
>-    m_moduleLoader.set(vm, this, JSModuleLoader::create(vm, this, m_moduleLoaderStructure.get()));
>+    m_moduleLoader.set(vm, this, JSModuleLoader::create(globalExec(), vm, this, m_moduleLoaderStructure.get()));
>     if (Options::exposeInternalModuleLoader())
>         putDirectWithoutTransition(vm, vm.propertyNames->Loader, m_moduleLoader.get(), DontEnum);
> 
>Index: Source/JavaScriptCore/runtime/JSMap.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSMap.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSMap.cpp	(working copy)
>@@ -26,78 +26,13 @@
> #include "config.h"
> #include "JSMap.h"
> 
>-#include "CopiedBlockInlines.h"
>-#include "JSCJSValueInlines.h"
>-#include "JSMapIterator.h"
>-#include "MapDataInlines.h"
>-#include "SlotVisitorInlines.h"
>-#include "StructureInlines.h"
>-
> namespace JSC {
> 
> const ClassInfo JSMap::s_info = { "Map", &Base::s_info, 0, CREATE_METHOD_TABLE(JSMap) };
> 
>-void JSMap::destroy(JSCell* cell)
>-{
>-    JSMap* thisObject = jsCast<JSMap*>(cell);
>-    thisObject->JSMap::~JSMap();
>-}
>-
>-size_t JSMap::estimatedSize(JSCell* cell)
>-{
>-    JSMap* thisObject = jsCast<JSMap*>(cell);
>-    size_t mapDataSize = thisObject->m_mapData.capacityInBytes();
>-    return Base::estimatedSize(cell) + mapDataSize;
>-}
>-
> String JSMap::toStringName(const JSObject*, ExecState*)
> {
>     return ASCIILiteral("Object");
> }
> 
>-void JSMap::visitChildren(JSCell* cell, SlotVisitor& visitor)
>-{
>-    Base::visitChildren(cell, visitor);
>-    jsCast<JSMap*>(cell)->m_mapData.visitChildren(cell, visitor);
>-}
>-
>-void JSMap::copyBackingStore(JSCell* cell, CopyVisitor& visitor, CopyToken token)
>-{
>-    Base::copyBackingStore(cell, visitor, token);
>-    jsCast<JSMap*>(cell)->m_mapData.copyBackingStore(visitor, token);
>-}
>-
>-bool JSMap::has(ExecState* exec, JSValue key)
>-{
>-    return m_mapData.contains(exec, key);
>-}
>-
>-size_t JSMap::size(ExecState* exec)
>-{
>-    return m_mapData.size(exec);
>-}
>-
>-JSValue JSMap::get(ExecState* exec, JSValue key)
>-{
>-    JSValue result = m_mapData.get(exec, key);
>-    if (!result)
>-        return jsUndefined();
>-    return result;
>-}
>-
>-void JSMap::set(ExecState* exec, JSValue key, JSValue value)
>-{
>-    m_mapData.set(exec, this, key, value);
>-}
>-
>-void JSMap::clear(ExecState*)
>-{
>-    m_mapData.clear();
>-}
>-
>-bool JSMap::remove(ExecState* exec, JSValue key)
>-{
>-    return m_mapData.remove(exec, key);
>-}
>-
> }
>Index: Source/JavaScriptCore/runtime/JSMap.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSMap.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSMap.h	(working copy)
>@@ -26,108 +26,49 @@
> #ifndef JSMap_h
> #define JSMap_h
> 
>-#include "JSDestructibleObject.h"
> #include "JSObject.h"
>-#include "MapData.h"
>+#include "MapBase.h"
> 
> namespace JSC {
> 
> class JSMapIterator;
> 
>-class JSMap : public JSDestructibleObject {
>+class JSMap : public MapBase<HashMapBucket<HashMapBucketDataKeyValue>> {
>+    typedef MapBase<HashMapBucket<HashMapBucketDataKeyValue>> Base;
> public:
>-    typedef JSDestructibleObject Base;
>-
>     friend class JSMapIterator;
> 
>-    // Our marking functions expect Entry to maintain this layout, and have all
>-    // fields be WriteBarrier<Unknown>
>-    class Entry {
>-    private:
>-        WriteBarrier<Unknown> m_key;
>-        WriteBarrier<Unknown> m_value;
>-
>-    public:
>-        const WriteBarrier<Unknown>& key() const
>-        {
>-            return m_key;
>-        }
>-
>-        const WriteBarrier<Unknown>& value() const
>-        {
>-            return m_value;
>-        }
>-
>-        void visitChildren(SlotVisitor& visitor)
>-        {
>-            visitor.append(&m_key);
>-            visitor.append(&m_value);
>-        }
>-
>-        void setKey(VM& vm, const JSCell* owner, JSValue key)
>-        {
>-            m_key.set(vm, owner, key);
>-        }
>-
>-        void setKeyWithoutWriteBarrier(JSValue key)
>-        {
>-            m_key.setWithoutWriteBarrier(key);
>-        }
>-
>-        void setValue(VM& vm, const JSCell* owner, JSValue value)
>-        {
>-            m_value.set(vm, owner, value);
>-        }
>-
>-        void clear()
>-        {
>-            m_key.clear();
>-            m_value.clear();
>-        }
>-    };
>-
>-    typedef MapDataImpl<Entry, JSMapIterator> MapData;
>-
>     DECLARE_EXPORT_INFO;
> 
>     static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
>     {
>-        return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
>+        return Structure::create(vm, globalObject, prototype, TypeInfo(JSMapType, StructureFlags), info());
>     }
> 
>-    static JSMap* create(VM& vm, Structure* structure)
>+    static JSMap* create(ExecState* exec, VM& vm, Structure* structure)
>     {
>         JSMap* instance = new (NotNull, allocateCell<JSMap>(vm.heap)) JSMap(vm, structure);
>-        instance->finishCreation(vm);
>+        instance->finishCreation(exec, vm);
>         return instance;
>     }
> 
>-    static JSMap* create(ExecState* exec, Structure* structure)
>+    ALWAYS_INLINE JSValue get(ExecState* exec, JSValue key)
>     {
>-        return create(exec->vm(), structure);
>+        return m_map->get(exec, key);
>     }
> 
>-    bool has(ExecState*, JSValue);
>-    size_t size(ExecState*);
>-    JSValue get(ExecState*, JSValue);
>-    JS_EXPORT_PRIVATE void set(ExecState*, JSValue key, JSValue value);
>-    void clear(ExecState*);
>-    bool remove(ExecState*, JSValue);
>+    ALWAYS_INLINE void set(ExecState* exec, JSValue key, JSValue value)
>+    {
>+        m_map->add(exec, key, value);
>+    }
> 
> private:
>     JSMap(VM& vm, Structure* structure)
>         : Base(vm, structure)
>-        , m_mapData(vm, this)
>     {
>     }
> 
>-    static void destroy(JSCell*);
>-    static size_t estimatedSize(JSCell*);
>-    static void visitChildren(JSCell*, SlotVisitor&);
>-    static void copyBackingStore(JSCell*, CopyVisitor&, CopyToken);
>     static String toStringName(const JSObject*, ExecState*);
>-
>-    MapData m_mapData;
> };
> 
> }
>Index: Source/JavaScriptCore/runtime/JSMapIterator.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSMapIterator.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSMapIterator.cpp	(working copy)
>@@ -26,6 +26,9 @@
> #include "config.h"
> #include "JSMapIterator.h"
> 
>+#include "BuiltinNames.h"
>+#include "CommonIdentifiers.h"
>+#include "IdentifierInlines.h"
> #include "JSCJSValueInlines.h"
> #include "JSCellInlines.h"
> #include "JSMap.h"
>@@ -41,6 +44,7 @@ void JSMapIterator::finishCreation(VM& v
> {
>     Base::finishCreation(vm);
>     m_map.set(vm, this, iteratedObject);
>+    setIterator(vm, m_map->impl()->head());
> }
> 
> void JSMapIterator::visitChildren(JSCell* cell, SlotVisitor& visitor)
>@@ -49,6 +53,7 @@ void JSMapIterator::visitChildren(JSCell
>     ASSERT_GC_OBJECT_INHERITS(thisObject, info());
>     Base::visitChildren(thisObject, visitor);
>     visitor.append(&thisObject->m_map);
>+    visitor.append(&thisObject->m_iter);
> }
> 
> JSValue JSMapIterator::createPair(CallFrame* callFrame, JSValue key, JSValue value)
>@@ -62,8 +67,9 @@ JSValue JSMapIterator::createPair(CallFr
> 
> JSMapIterator* JSMapIterator::clone(ExecState* exec)
> {
>-    auto clone = JSMapIterator::create(exec->vm(), exec->callee()->globalObject()->mapIteratorStructure(), m_map.get(), m_kind);
>-    clone->m_iterator = m_iterator;
>+    VM& vm = exec->vm();
>+    auto clone = JSMapIterator::create(vm, exec->callee()->globalObject()->mapIteratorStructure(), m_map.get(), m_kind);
>+    clone->setIterator(vm, m_iter.get());
>     return clone;
> }
> 
>Index: Source/JavaScriptCore/runtime/JSMapIterator.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSMapIterator.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSMapIterator.h	(working copy)
>@@ -34,6 +34,7 @@
> namespace JSC {
> 
> class JSMapIterator : public JSNonFinalObject {
>+    typedef HashMapBucket<HashMapBucketDataKeyValue> HashMapBucket;
> public:
>     typedef JSNonFinalObject Base;
> 
>@@ -51,52 +52,62 @@ public:
>         return instance;
>     }
> 
>-    bool next(CallFrame* callFrame, JSValue& value)
>+    ALWAYS_INLINE HashMapBucket* advanceIter(ExecState* exec)
>     {
>-        WTF::KeyValuePair<JSValue, JSValue> pair;
>-        if (!m_iterator.next(pair))
>+        HashMapBucket* prev = m_iter.get();
>+        if (!prev)
>+            return nullptr;
>+        HashMapBucket* bucket = m_iter->next();
>+        while (bucket && bucket->deleted()) {
>+            prev = bucket;
>+            bucket = bucket->next();
>+        }
>+        if (!bucket) {
>+            setIterator(exec->vm(), nullptr);
>+            return nullptr;
>+        }
>+        setIterator(exec->vm(), bucket); // We keep m_iter on the last value since the first thing we do in this function is call next().
>+        return bucket;
>+    }
>+    bool next(ExecState* exec, JSValue& value)
>+    {
>+        HashMapBucket* bucket = advanceIter(exec);
>+        if (!bucket)
>             return false;
> 
>         if (m_kind == IterateValue)
>-            value = pair.value;
>+            value = bucket->value();
>         else if (m_kind == IterateKey)
>-            value = pair.key;
>+            value = bucket->key();
>         else
>-            value = createPair(callFrame, pair.key, pair.value);
>+            value = createPair(exec, bucket->key(), bucket->value());
>         return true;
>     }
> 
>-    bool nextKeyValue(JSValue& key, JSValue& value)
>+    bool nextKeyValue(ExecState* exec, JSValue& key, JSValue& value)
>     {
>-        WTF::KeyValuePair<JSValue, JSValue> pair;
>-        if (!m_iterator.next(pair))
>+        HashMapBucket* bucket = advanceIter(exec);
>+        if (!bucket)
>             return false;
> 
>-        key = pair.key;
>-        value = pair.value;
>+        key = bucket->key();
>+        value = bucket->value();
>         return true;
>     }
> 
>-    void finish()
>-    {
>-        m_iterator.finish();
>-    }
>-
>     IterationKind kind() const { return m_kind; }
>     JSValue iteratedValue() const { return m_map.get(); }
>     JSMapIterator* clone(ExecState*);
> 
>-    JSMap::MapData::IteratorData* iteratorData()
>-    {
>-        return &m_iterator;
>-    }
>-
> private:
>-    JSMapIterator(VM& vm, Structure* structure, JSMap* iteratedObject, IterationKind kind)
>+    JSMapIterator(VM& vm, Structure* structure, JSMap*, IterationKind kind)
>         : Base(vm, structure)
>-        , m_iterator(iteratedObject->m_mapData.createIteratorData(this))
>         , m_kind(kind)
>+    { }
>+
>+    void setIterator(VM& vm, HashMapBucket* bucket)
>     {
>+        m_iter.setMayBeNull(vm, this, bucket);
>     }
> 
>     JS_EXPORT_PRIVATE void finishCreation(VM&, JSMap*);
>@@ -104,7 +115,7 @@ private:
>     static void visitChildren(JSCell*, SlotVisitor&);
> 
>     WriteBarrier<JSMap> m_map;
>-    JSMap::MapData::IteratorData m_iterator;
>+    WriteBarrier<HashMapBucket> m_iter;
>     IterationKind m_kind;
> };
> STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(JSMapIterator);
>Index: Source/JavaScriptCore/runtime/JSModuleLoader.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSModuleLoader.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSModuleLoader.cpp	(working copy)
>@@ -55,11 +55,14 @@ JSModuleLoader::JSModuleLoader(VM& vm, S
> {
> }
> 
>-void JSModuleLoader::finishCreation(VM& vm, JSGlobalObject* globalObject)
>+void JSModuleLoader::finishCreation(ExecState* exec, VM& vm, JSGlobalObject* globalObject)
> {
>     Base::finishCreation(vm);
>     ASSERT(inherits(info()));
>-    putDirect(vm, Identifier::fromString(&vm, "registry"), JSMap::create(vm, globalObject->mapStructure()));
>+    auto scope = DECLARE_THROW_SCOPE(vm);
>+    JSMap* map = JSMap::create(exec, vm, globalObject->mapStructure());
>+    RELEASE_ASSERT(!scope.exception());
>+    putDirect(vm, Identifier::fromString(&vm, "registry"), map);
> }
> 
> // ------------------------------ Functions --------------------------------
>Index: Source/JavaScriptCore/runtime/JSModuleLoader.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSModuleLoader.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSModuleLoader.h	(working copy)
>@@ -47,10 +47,10 @@ public:
>         Ready = 6,
>     };
> 
>-    static JSModuleLoader* create(VM& vm, JSGlobalObject* globalObject, Structure* structure)
>+    static JSModuleLoader* create(ExecState* exec, VM& vm, JSGlobalObject* globalObject, Structure* structure)
>     {
>         JSModuleLoader* object = new (NotNull, allocateCell<JSModuleLoader>(vm.heap)) JSModuleLoader(vm, structure);
>-        object->finishCreation(vm, globalObject);
>+        object->finishCreation(exec, vm, globalObject);
>         return object;
>     }
> 
>@@ -77,7 +77,7 @@ public:
>     JSValue evaluate(ExecState*, JSValue key, JSValue moduleRecord, JSValue initiator);
> 
> protected:
>-    void finishCreation(VM&, JSGlobalObject*);
>+    void finishCreation(ExecState*, VM&, JSGlobalObject*);
> };
> 
> } // namespace JSC
>Index: Source/JavaScriptCore/runtime/JSModuleRecord.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSModuleRecord.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSModuleRecord.cpp	(working copy)
>@@ -47,14 +47,17 @@ void JSModuleRecord::destroy(JSCell* cel
>     thisObject->JSModuleRecord::~JSModuleRecord();
> }
> 
>-void JSModuleRecord::finishCreation(VM& vm)
>+void JSModuleRecord::finishCreation(ExecState* exec, VM& vm)
> {
>     Base::finishCreation(vm);
>     ASSERT(inherits(info()));
>     putDirect(vm, Identifier::fromString(&vm, ASCIILiteral("registryEntry")), jsUndefined());
>     putDirect(vm, Identifier::fromString(&vm, ASCIILiteral("evaluated")), jsBoolean(false));
> 
>-    m_dependenciesMap.set(vm, this, JSMap::create(vm, globalObject()->mapStructure()));
>+    auto scope = DECLARE_THROW_SCOPE(vm);
>+    JSMap* map = JSMap::create(exec, vm, globalObject()->mapStructure());
>+    RELEASE_ASSERT(!scope.exception());
>+    m_dependenciesMap.set(vm, this, map);
>     putDirect(vm, Identifier::fromString(&vm, ASCIILiteral("dependenciesMap")), m_dependenciesMap.get());
> }
> 
>Index: Source/JavaScriptCore/runtime/JSModuleRecord.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSModuleRecord.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSModuleRecord.h	(working copy)
>@@ -87,10 +87,10 @@ public:
>         return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
>     }
> 
>-    static JSModuleRecord* create(VM& vm, Structure* structure, const Identifier& moduleKey, const SourceCode& sourceCode, const VariableEnvironment& declaredVariables, const VariableEnvironment& lexicalVariables)
>+    static JSModuleRecord* create(ExecState* exec, VM& vm, Structure* structure, const Identifier& moduleKey, const SourceCode& sourceCode, const VariableEnvironment& declaredVariables, const VariableEnvironment& lexicalVariables)
>     {
>         JSModuleRecord* instance = new (NotNull, allocateCell<JSModuleRecord>(vm.heap)) JSModuleRecord(vm, structure, moduleKey, sourceCode, declaredVariables, lexicalVariables);
>-        instance->finishCreation(vm);
>+        instance->finishCreation(exec, vm);
>         return instance;
>     }
> 
>@@ -152,7 +152,7 @@ private:
>     {
>     }
> 
>-    void finishCreation(VM&);
>+    void finishCreation(ExecState*, VM&);
> 
>     JSModuleNamespaceObject* getModuleNamespace(ExecState*);
> 
>Index: Source/JavaScriptCore/runtime/JSSet.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSSet.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSSet.cpp	(working copy)
>@@ -26,70 +26,13 @@
> #include "config.h"
> #include "JSSet.h"
> 
>-#include "CopiedBlockInlines.h"
>-#include "JSCJSValueInlines.h"
>-#include "JSSetIterator.h"
>-#include "MapDataInlines.h"
>-#include "SlotVisitorInlines.h"
>-#include "StructureInlines.h"
>-
> namespace JSC {
> 
> const ClassInfo JSSet::s_info = { "Set", &Base::s_info, 0, CREATE_METHOD_TABLE(JSSet) };
> 
>-void JSSet::destroy(JSCell* cell)
>-{
>-    JSSet* thisObject = jsCast<JSSet*>(cell);
>-    thisObject->JSSet::~JSSet();
>-}
>-
> String JSSet::toStringName(const JSObject*, ExecState*)
> {
>     return ASCIILiteral("Object");
> }
> 
>-size_t JSSet::estimatedSize(JSCell* cell)
>-{
>-    JSSet* thisObject = jsCast<JSSet*>(cell);
>-    size_t setDataSize = thisObject->m_setData.capacityInBytes();
>-    return Base::estimatedSize(cell) + setDataSize;
>-}
>-
>-void JSSet::visitChildren(JSCell* cell, SlotVisitor& visitor)
>-{
>-    Base::visitChildren(cell, visitor);
>-    jsCast<JSSet*>(cell)->m_setData.visitChildren(cell, visitor);
>-}
>-
>-void JSSet::copyBackingStore(JSCell* cell, CopyVisitor& visitor, CopyToken token)
>-{
>-    Base::copyBackingStore(cell, visitor, token);
>-    jsCast<JSSet*>(cell)->m_setData.copyBackingStore(visitor, token);
>-}
>-
>-bool JSSet::has(ExecState* exec, JSValue value)
>-{
>-    return m_setData.contains(exec, value);
>-}
>-
>-size_t JSSet::size(ExecState* exec)
>-{
>-    return m_setData.size(exec);
>-}
>-
>-void JSSet::add(ExecState* exec, JSValue value)
>-{
>-    m_setData.set(exec, this, value, value);
>-}
>-
>-void JSSet::clear(ExecState*)
>-{
>-    m_setData.clear();
>-}
>-
>-bool JSSet::remove(ExecState* exec, JSValue value)
>-{
>-    return m_setData.remove(exec, value);
>-}
>-
> }
>Index: Source/JavaScriptCore/runtime/JSSet.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSSet.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSSet.h	(working copy)
>@@ -26,103 +26,45 @@
> #ifndef JSSet_h
> #define JSSet_h
> 
>-#include "JSDestructibleObject.h"
> #include "JSObject.h"
>-#include "MapData.h"
>+#include "MapBase.h"
> 
> namespace JSC {
> 
> class JSSetIterator;
> 
>-class JSSet : public JSDestructibleObject {
>+class JSSet : public MapBase<HashMapBucket<HashMapBucketDataKey>> {
>+    typedef MapBase<HashMapBucket<HashMapBucketDataKey>> Base;
> public:
>-    typedef JSDestructibleObject Base;
> 
>     friend class JSSetIterator;
> 
>-    // Our marking functions expect Entry to maintain this layout, and have all
>-    // fields be WriteBarrier<Unknown>
>-    class Entry {
>-    private:
>-        WriteBarrier<Unknown> m_key;
>-
>-    public:
>-        const WriteBarrier<Unknown>& key() const
>-        {
>-            return m_key;
>-        }
>-
>-        const WriteBarrier<Unknown>& value() const
>-        {
>-            return m_key;
>-        }
>-
>-        void visitChildren(SlotVisitor& visitor)
>-        {
>-            visitor.append(&m_key);
>-        }
>-
>-        void setKey(VM& vm, const JSCell* owner, JSValue key)
>-        {
>-            m_key.set(vm, owner, key);
>-        }
>-
>-        void setKeyWithoutWriteBarrier(JSValue key)
>-        {
>-            m_key.setWithoutWriteBarrier(key);
>-        }
>-
>-        void setValue(VM&, const JSCell*, JSValue)
>-        {
>-        }
>-
>-        void clear()
>-        {
>-            m_key.clear();
>-        }
>-    };
>-
>-    typedef MapDataImpl<Entry, JSSetIterator> SetData;
>-
>     DECLARE_EXPORT_INFO;
> 
>     static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
>     {
>-        return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
>+        return Structure::create(vm, globalObject, prototype, TypeInfo(JSSetType, StructureFlags), info());
>     }
> 
>-    static JSSet* create(VM& vm, Structure* structure)
>+    static JSSet* create(ExecState* exec, VM& vm, Structure* structure)
>     {
>         JSSet* instance = new (NotNull, allocateCell<JSSet>(vm.heap)) JSSet(vm, structure);
>-        instance->finishCreation(vm);
>+        instance->finishCreation(exec, vm);
>         return instance;
>     }
> 
>-    static JSSet* create(ExecState* exec, Structure* structure)
>+    ALWAYS_INLINE void add(ExecState* exec, JSValue key)
>     {
>-        return create(exec->vm(), structure);
>+        m_map->add(exec, key);
>     }
> 
>-    bool has(ExecState*, JSValue);
>-    size_t size(ExecState*);
>-    JS_EXPORT_PRIVATE void add(ExecState*, JSValue);
>-    void clear(ExecState*);
>-    bool remove(ExecState*, JSValue);
>-
> private:
>     JSSet(VM& vm, Structure* structure)
>         : Base(vm, structure)
>-        , m_setData(vm, this)
>     {
>     }
> 
>-    static void destroy(JSCell*);
>-    static size_t estimatedSize(JSCell*);
>-    static void visitChildren(JSCell*, SlotVisitor&);
>-    static void copyBackingStore(JSCell*, CopyVisitor&, CopyToken);
>     static String toStringName(const JSObject*, ExecState*);
>-
>-    SetData m_setData;
> };
> 
> }
>Index: Source/JavaScriptCore/runtime/JSSetIterator.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSSetIterator.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSSetIterator.cpp	(working copy)
>@@ -41,6 +41,7 @@ void JSSetIterator::finishCreation(VM& v
> {
>     Base::finishCreation(vm);
>     m_set.set(vm, this, iteratedObject);
>+    setIterator(vm, m_set->impl()->head());
> }
> 
> void JSSetIterator::visitChildren(JSCell* cell, SlotVisitor& visitor)
>@@ -49,6 +50,7 @@ void JSSetIterator::visitChildren(JSCell
>     ASSERT_GC_OBJECT_INHERITS(thisObject, info());
>     Base::visitChildren(thisObject, visitor);
>     visitor.append(&thisObject->m_set);
>+    visitor.append(&thisObject->m_iter);
> }
> 
> JSValue JSSetIterator::createPair(CallFrame* callFrame, JSValue key, JSValue value)
>@@ -62,8 +64,9 @@ JSValue JSSetIterator::createPair(CallFr
> 
> JSSetIterator* JSSetIterator::clone(ExecState* exec)
> {
>-    auto clone = JSSetIterator::create(exec->vm(), exec->callee()->globalObject()->setIteratorStructure(), m_set.get(), m_kind);
>-    clone->m_iterator = m_iterator;
>+    VM& vm = exec->vm();
>+    auto clone = JSSetIterator::create(vm, exec->callee()->globalObject()->setIteratorStructure(), m_set.get(), m_kind);
>+    clone->setIterator(vm, m_iter.get());
>     return clone;
> }
> 
>Index: Source/JavaScriptCore/runtime/JSSetIterator.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSSetIterator.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSSetIterator.h	(working copy)
>@@ -35,6 +35,7 @@
> namespace JSC {
> 
> class JSSetIterator : public JSNonFinalObject {
>+    typedef HashMapBucket<HashMapBucketDataKey> HashMapBucket;
> public:
>     typedef JSNonFinalObject Base;
> 
>@@ -52,46 +53,59 @@ public:
>         return instance;
>     }
> 
>-    bool next(CallFrame* callFrame, JSValue& value)
>+    ALWAYS_INLINE HashMapBucket* advanceIter(ExecState* exec)
>     {
>-        WTF::KeyValuePair<JSValue, JSValue> pair;
>-        if (!m_iterator.next(pair))
>+        HashMapBucket* prev = m_iter.get();
>+        if (!prev)
>+            return nullptr;
>+        HashMapBucket* bucket = m_iter->next();
>+        while (bucket && bucket->deleted()) {
>+            prev = bucket;
>+            bucket = bucket->next();
>+        }
>+        if (!bucket) {
>+            setIterator(exec->vm(), nullptr);
>+            return nullptr;
>+        }
>+        setIterator(exec->vm(), bucket); // We keep m_iter on the last value since the first thing we do in this function is call next().
>+        return bucket;
>+    }
>+
>+    bool next(ExecState* exec, JSValue& value)
>+    {
>+        HashMapBucket* bucket = advanceIter(exec);
>+        if (!bucket)
>             return false;
>+
>         if (m_kind == IterateValue || m_kind == IterateKey)
>-            value = pair.key;
>+            value = bucket->key();
>         else
>-            value = createPair(callFrame, pair.key, pair.key);
>+            value = createPair(exec, bucket->key(), bucket->key());
>         return true;
>     }
> 
>-    void finish()
>-    {
>-        m_iterator.finish();
>-    }
>-
>     IterationKind kind() const { return m_kind; }
>     JSValue iteratedValue() const { return m_set.get(); }
>     JSSetIterator* clone(ExecState*);
> 
>-    JSSet::SetData::IteratorData* iteratorData()
>-    {
>-        return &m_iterator;
>-    }
>-
> private:
>-    JSSetIterator(VM& vm, Structure* structure, JSSet* iteratedObject, IterationKind kind)
>+    JSSetIterator(VM& vm, Structure* structure, JSSet*, IterationKind kind)
>         : Base(vm, structure)
>-        , m_iterator(iteratedObject->m_setData.createIteratorData(this))
>         , m_kind(kind)
>     {
>     }
> 
>+    void setIterator(VM& vm, HashMapBucket* bucket)
>+    {
>+        m_iter.setMayBeNull(vm, this, bucket); 
>+    }
>+
>     JS_EXPORT_PRIVATE void finishCreation(VM&, JSSet*);
>     JS_EXPORT_PRIVATE JSValue createPair(CallFrame*, JSValue, JSValue);
>     static void visitChildren(JSCell*, SlotVisitor&);
> 
>     WriteBarrier<JSSet> m_set;
>-    JSSet::SetData::IteratorData m_iterator;
>+    WriteBarrier<HashMapBucket> m_iter;
>     IterationKind m_kind;
> };
> STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(JSSetIterator);
>Index: Source/JavaScriptCore/runtime/JSType.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSType.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/JSType.h	(working copy)
>@@ -82,8 +82,10 @@ enum JSType : uint8_t {
>     ModuleEnvironmentType,
>     RegExpObjectType,
>     ProxyObjectType,
>+    JSMapType,
>+    JSSetType,
> 
>-    LastJSCObjectType = ProxyObjectType,
>+    LastJSCObjectType = JSSetType,
> };
> 
> COMPILE_ASSERT(sizeof(JSType) == sizeof(uint8_t), sizeof_jstype_is_one_byte);
>Index: Source/JavaScriptCore/runtime/MapBase.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/MapBase.cpp	(nonexistent)
>+++ Source/JavaScriptCore/runtime/MapBase.cpp	(working copy)
>@@ -0,0 +1,50 @@
>+/*
>+ * Copyright (C) 2016 Apple Inc. All rights reserved.
>+ *
>+ * Redistribution and use in source and binary forms, with or without
>+ * modification, are permitted provided that the following conditions
>+ * are met:
>+ * 1. Redistributions of source code must retain the above copyright
>+ *    notice, this list of conditions and the following disclaimer.
>+ * 2. Redistributions in binary form must reproduce the above copyright
>+ *    notice, this list of conditions and the following disclaimer in the
>+ *    documentation and/or other materials provided with the distribution.
>+ *
>+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
>+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
>+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
>+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
>+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
>+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
>+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
>+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
>+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
>+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
>+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
>+ */
>+
>+#include "config.h"
>+#include "MapBase.h"
>+
>+#include "SlotVisitorInlines.h"
>+
>+namespace JSC {
>+
>+template <typename HashMapBucketType>
>+void MapBase<HashMapBucketType>::visitChildren(JSCell* cell, SlotVisitor& visitor)
>+{
>+    MapBase* thisObject = static_cast<MapBase*>(cell);
>+    Base::visitChildren(thisObject, visitor);
>+    visitor.append(&thisObject->m_map);
>+}
>+
>+template <typename HashMapBucketType>
>+size_t MapBase<HashMapBucketType>::estimatedSize(JSCell* cell)
>+{
>+    return Base::estimatedSize(cell) + static_cast<MapBase*>(cell)->m_map->approximateSize();
>+}
>+
>+template class MapBase<HashMapBucket<HashMapBucketDataKeyValue>>;
>+template class MapBase<HashMapBucket<HashMapBucketDataKey>>;
>+
>+} // namespace JSC
>Index: Source/JavaScriptCore/runtime/MapBase.h
>===================================================================
>--- Source/JavaScriptCore/runtime/MapBase.h	(nonexistent)
>+++ Source/JavaScriptCore/runtime/MapBase.h	(working copy)
>@@ -0,0 +1,95 @@
>+/*
>+ * Copyright (C) 2016 Apple Inc. All rights reserved.
>+ *
>+ * Redistribution and use in source and binary forms, with or without
>+ * modification, are permitted provided that the following conditions
>+ * are met:
>+ * 1. Redistributions of source code must retain the above copyright
>+ *    notice, this list of conditions and the following disclaimer.
>+ * 2. Redistributions in binary form must reproduce the above copyright
>+ *    notice, this list of conditions and the following disclaimer in the
>+ *    documentation and/or other materials provided with the distribution.
>+ *
>+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
>+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
>+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
>+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
>+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
>+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
>+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
>+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
>+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
>+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
>+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
>+ */
>+
>+#pragma once
>+
>+#include "HashMapImpl.h"
>+#include "JSObject.h"
>+
>+namespace JSC {
>+
>+template <typename HashMapBucketType>
>+class MapBase : public JSNonFinalObject {
>+    typedef HashMapImpl<HashMapBucketType> HashMapImpl;
>+    typedef JSNonFinalObject Base;
>+public:
>+
>+    typedef HashMapBucketType BucketType;
>+
>+    ALWAYS_INLINE size_t size(ExecState*)
>+    {
>+        return m_map->size();
>+    }
>+
>+    ALWAYS_INLINE bool has(ExecState* exec, JSValue key)
>+    {
>+        return m_map->has(exec, key);
>+    }
>+
>+    ALWAYS_INLINE void clear(ExecState* exec)
>+    {
>+        m_map->clear(exec);
>+    }
>+
>+    ALWAYS_INLINE bool remove(ExecState* exec, JSValue key)
>+    {
>+        return m_map->remove(exec, key);
>+    }
>+
>+    ALWAYS_INLINE HashMapBucketType** findBucket(ExecState* exec, JSValue key, uint32_t hash)
>+    {
>+        return m_map->findBucket(exec, key, hash);
>+    }
>+
>+    static ptrdiff_t offsetOfHashMapImpl()
>+    {
>+        return OBJECT_OFFSETOF(MapBase<HashMapBucketType>, m_map);
>+    }
>+
>+    ALWAYS_INLINE HashMapImpl* impl() { return m_map.get(); }
>+
>+    void finishCreation(ExecState* exec, VM& vm)
>+    {
>+        Base::finishCreation(vm);
>+        auto scope = DECLARE_THROW_SCOPE(vm);
>+        HashMapImpl* impl = HashMapImpl::create(exec, vm);
>+        if (UNLIKELY(scope.exception()))
>+            return;
>+        m_map.set(vm, this, impl);
>+    }
>+
>+protected:
>+    MapBase(VM& vm, Structure* structure)
>+        : Base(vm, structure)
>+    {
>+    }
>+
>+    static size_t estimatedSize(JSCell*);
>+    static void visitChildren(JSCell*, SlotVisitor&);
>+
>+    WriteBarrier<HashMapImpl> m_map;
>+};
>+
>+} // namespace JSC
>Index: Source/JavaScriptCore/runtime/MapConstructor.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/MapConstructor.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/MapConstructor.cpp	(working copy)
>@@ -62,9 +62,11 @@ static EncodedJSValue JSC_HOST_CALL cons
> 
>     JSGlobalObject* globalObject = asInternalFunction(exec->callee())->globalObject();
>     Structure* mapStructure = InternalFunction::createSubclassStructure(exec, exec->newTarget(), globalObject->mapStructure());
>-    if (exec->hadException())
>+    if (UNLIKELY(scope.exception()))
>+        return JSValue::encode(JSValue());
>+    JSMap* map = JSMap::create(exec, vm, mapStructure);
>+    if (UNLIKELY(scope.exception()))
>         return JSValue::encode(JSValue());
>-    JSMap* map = JSMap::create(exec, mapStructure);
>     JSValue iterable = exec->argument(0);
>     if (iterable.isUndefinedOrNull())
>         return JSValue::encode(map);
>Index: Source/JavaScriptCore/runtime/MapIteratorPrototype.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/MapIteratorPrototype.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/MapIteratorPrototype.cpp	(working copy)
>@@ -60,7 +60,6 @@ EncodedJSValue JSC_HOST_CALL MapIterator
>     JSValue result;
>     if (iterator->next(callFrame, result))
>         return JSValue::encode(createIteratorResultObject(callFrame, result, false));
>-    iterator->finish();
>     return JSValue::encode(createIteratorResultObject(callFrame, jsUndefined(), true));
> }
> 
>Index: Source/JavaScriptCore/runtime/MapPrototype.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/MapPrototype.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/MapPrototype.cpp	(working copy)
>@@ -70,14 +70,13 @@ void MapPrototype::finishCreation(VM& vm
> 
>     JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->clear, mapProtoFuncClear, DontEnum, 0);
>     JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->deleteKeyword, mapProtoFuncDelete, DontEnum, 1);
>-    JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->get, mapProtoFuncGet, DontEnum, 1);
>-    JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->has, mapProtoFuncHas, DontEnum, 1);
>+    JSC_NATIVE_INTRINSIC_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->get, mapProtoFuncGet, DontEnum, 1, JSMapGetIntrinsic);
>+    JSC_NATIVE_INTRINSIC_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->has, mapProtoFuncHas, DontEnum, 1, JSMapHasIntrinsic);
>     JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->set, mapProtoFuncSet, DontEnum, 2);
>     JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->builtinNames().keysPublicName(), mapProtoFuncKeys, DontEnum, 0);
>     JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->builtinNames().valuesPublicName(), mapProtoFuncValues, DontEnum, 0);
> 
>-    // Private get / set operations.
>-    JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->builtinNames().getPrivateName(), mapProtoFuncGet, DontEnum, 1);
>+    JSC_NATIVE_INTRINSIC_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->builtinNames().getPrivateName(), mapProtoFuncGet, DontEnum, 1, JSMapGetIntrinsic);
>     JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->builtinNames().setPrivateName(), mapProtoFuncSet, DontEnum, 2);
> 
>     JSFunction* entries = JSFunction::create(vm, globalObject, 0, vm.propertyNames->builtinNames().entriesPublicName().string(), mapProtoFuncEntries);
>@@ -93,16 +92,21 @@ ALWAYS_INLINE static JSMap* getMap(CallF
>     VM& vm = callFrame->vm();
>     auto scope = DECLARE_THROW_SCOPE(vm);
> 
>-    if (!thisValue.isObject()) {
>+    if (UNLIKELY(!thisValue.isCell())) {
>         throwVMError(callFrame, scope, createNotAnObjectError(callFrame, thisValue));
>         return nullptr;
>     }
>-    JSMap* map = jsDynamicCast<JSMap*>(thisValue);
>-    if (!map) {
>-        throwTypeError(callFrame, scope, ASCIILiteral("Map operation called on non-Map object"));
>-        return nullptr;
>-    }
>-    return map;
>+
>+    if (LIKELY(thisValue.asCell()->type() == JSMapType))
>+        return jsCast<JSMap*>(thisValue);
>+    throwTypeError(callFrame, scope, ASCIILiteral("Map operation called on non-Map object"));
>+    return nullptr;
>+}
>+
>+EncodedJSValue JSC_HOST_CALL privateFuncIsMap(ExecState* exec)
>+{
>+    JSValue value = exec->uncheckedArgument(0);
>+    return JSValue::encode(jsBoolean(value.isCell() && value.asCell()->type() == JSMapType));
> }
> 
> EncodedJSValue JSC_HOST_CALL mapProtoFuncClear(CallFrame* callFrame)
>@@ -189,11 +193,6 @@ EncodedJSValue JSC_HOST_CALL mapProtoFun
>     return JSValue::encode(JSMapIterator::create(vm, callFrame->callee()->globalObject()->mapIteratorStructure(), thisObj, IterateKey));
> }
> 
>-EncodedJSValue JSC_HOST_CALL privateFuncIsMap(ExecState* exec)
>-{
>-    return JSValue::encode(jsBoolean(jsDynamicCast<JSMap*>(exec->uncheckedArgument(0))));
>-}
>-
> EncodedJSValue JSC_HOST_CALL privateFuncMapIterator(ExecState* exec)
> {
>     ASSERT(jsDynamicCast<JSMap*>(exec->uncheckedArgument(0)));
>@@ -206,13 +205,12 @@ EncodedJSValue JSC_HOST_CALL privateFunc
>     ASSERT(jsDynamicCast<JSMapIterator*>(exec->thisValue()));
>     JSMapIterator* iterator = jsCast<JSMapIterator*>(exec->thisValue());
>     JSValue key, value;
>-    if (iterator->nextKeyValue(key, value)) {
>+    if (iterator->nextKeyValue(exec, key, value)) {
>         JSArray* resultArray = jsCast<JSArray*>(exec->uncheckedArgument(0));
>         resultArray->putDirectIndex(exec, 0, key);
>         resultArray->putDirectIndex(exec, 1, value);
>         return JSValue::encode(jsBoolean(false));
>     }
>-    iterator->finish();
>     return JSValue::encode(jsBoolean(true));
> }
> 
>Index: Source/JavaScriptCore/runtime/PropertyDescriptor.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/PropertyDescriptor.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/PropertyDescriptor.cpp	(working copy)
>@@ -191,22 +191,6 @@ void PropertyDescriptor::setGetter(JSVal
>     m_attributes &= ~ReadOnly;
> }
> 
>-// See ES5.1 9.12
>-bool sameValue(ExecState* exec, JSValue a, JSValue b)
>-{
>-    if (!a.isNumber())
>-        return JSValue::strictEqual(exec, a, b);
>-    if (!b.isNumber())
>-        return false;
>-    double x = a.asNumber();
>-    double y = b.asNumber();
>-    bool xIsNaN = std::isnan(x);
>-    bool yIsNaN = std::isnan(y);
>-    if (xIsNaN || yIsNaN)
>-        return xIsNaN && yIsNaN;
>-    return bitwise_cast<uint64_t>(x) == bitwise_cast<uint64_t>(y);
>-}
>-
> bool PropertyDescriptor::equalTo(ExecState* exec, const PropertyDescriptor& other) const
> {
>     if (other.m_value.isEmpty() != m_value.isEmpty()
>Index: Source/JavaScriptCore/runtime/PropertyDescriptor.h
>===================================================================
>--- Source/JavaScriptCore/runtime/PropertyDescriptor.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/PropertyDescriptor.h	(working copy)
>@@ -32,9 +32,6 @@ namespace JSC {
> 
> class GetterSetter;
> 
>-// See ES5.1 9.12
>-bool sameValue(ExecState*, JSValue, JSValue);
>-
> class PropertyDescriptor {
> public:
>     PropertyDescriptor()
>Index: Source/JavaScriptCore/runtime/SetConstructor.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/SetConstructor.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/SetConstructor.cpp	(working copy)
>@@ -63,9 +63,11 @@ static EncodedJSValue JSC_HOST_CALL cons
> 
>     JSGlobalObject* globalObject = asInternalFunction(exec->callee())->globalObject();
>     Structure* setStructure = InternalFunction::createSubclassStructure(exec, exec->newTarget(), globalObject->setStructure());
>-    if (exec->hadException())
>+    if (UNLIKELY(scope.exception()))
>+        return JSValue::encode(JSValue());
>+    JSSet* set = JSSet::create(exec, vm, setStructure);
>+    if (UNLIKELY(scope.exception()))
>         return JSValue::encode(JSValue());
>-    JSSet* set = JSSet::create(exec, setStructure);
>     JSValue iterable = exec->argument(0);
>     if (iterable.isUndefinedOrNull())
>         return JSValue::encode(set);
>Index: Source/JavaScriptCore/runtime/SetIteratorPrototype.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/SetIteratorPrototype.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/SetIteratorPrototype.cpp	(working copy)
>@@ -60,7 +60,6 @@ EncodedJSValue JSC_HOST_CALL SetIterator
> 
>     if (iterator->next(callFrame, result))
>         return JSValue::encode(createIteratorResultObject(callFrame, result, false));
>-    iterator->finish();
>     return JSValue::encode(createIteratorResultObject(callFrame, jsUndefined(), true));
> }
> 
>Index: Source/JavaScriptCore/runtime/SetPrototype.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/SetPrototype.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/SetPrototype.cpp	(working copy)
>@@ -70,7 +70,7 @@ void SetPrototype::finishCreation(VM& vm
>     JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->add, setProtoFuncAdd, DontEnum, 1);
>     JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->clear, setProtoFuncClear, DontEnum, 0);
>     JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->deleteKeyword, setProtoFuncDelete, DontEnum, 1);
>-    JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->has, setProtoFuncHas, DontEnum, 1);
>+    JSC_NATIVE_INTRINSIC_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->has, setProtoFuncHas, DontEnum, 1, JSSetHasIntrinsic);
>     JSC_NATIVE_FUNCTION_WITHOUT_TRANSITION(vm.propertyNames->builtinNames().entriesPublicName(), setProtoFuncEntries, DontEnum, 0);
> 
>     JSFunction* values = JSFunction::create(vm, globalObject, 0, vm.propertyNames->builtinNames().valuesPublicName().string(), setProtoFuncValues);
>@@ -87,16 +87,14 @@ ALWAYS_INLINE static JSSet* getSet(CallF
>     VM& vm = callFrame->vm();
>     auto scope = DECLARE_THROW_SCOPE(vm);
> 
>-    if (!thisValue.isObject()) {
>+    if (UNLIKELY(!thisValue.isCell())) {
>         throwVMError(callFrame, scope, createNotAnObjectError(callFrame, thisValue));
>         return nullptr;
>     }
>-    JSSet* set = jsDynamicCast<JSSet*>(thisValue);
>-    if (!set) {
>-        throwTypeError(callFrame, scope, ASCIILiteral("Set operation called on non-Set object"));
>-        return nullptr;
>-    }
>-    return set;
>+    if (LIKELY(thisValue.asCell()->type() == JSSetType))
>+        return jsCast<JSSet*>(thisValue);
>+    throwTypeError(callFrame, scope, ASCIILiteral("Set operation called on non-Set object"));
>+    return nullptr;
> }
> 
> EncodedJSValue JSC_HOST_CALL setProtoFuncAdd(CallFrame* callFrame)
>@@ -186,7 +184,6 @@ EncodedJSValue JSC_HOST_CALL privateFunc
>         resultArray->putDirectIndex(exec, 0, result);
>         return JSValue::encode(jsBoolean(false));
>     }
>-    iterator->finish();
>     return JSValue::encode(jsBoolean(true));
> }
> 
>Index: Source/JavaScriptCore/runtime/VM.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/VM.cpp	(revision 205305)
>+++ Source/JavaScriptCore/runtime/VM.cpp	(working copy)
>@@ -65,6 +65,7 @@
> #include "JSInternalPromiseDeferred.h"
> #include "JSLexicalEnvironment.h"
> #include "JSLock.h"
>+#include "JSMap.h"
> #include "JSPromiseDeferred.h"
> #include "JSPropertyNameEnumerator.h"
> #include "JSTemplateRegistryKey.h"
>@@ -249,6 +250,10 @@ VM::VM(VMType vmType, HeapType heapType)
> #if ENABLE(WEBASSEMBLY)
>     webAssemblyCodeBlockStructure.set(*this, WebAssemblyCodeBlock::createStructure(*this, 0, jsNull()));
> #endif
>+    hashMapBucketSetStructure.set(*this, HashMapBucket<HashMapBucketDataKey>::createStructure(*this, 0, jsNull()));
>+    hashMapBucketMapStructure.set(*this, HashMapBucket<HashMapBucketDataKeyValue>::createStructure(*this, 0, jsNull()));
>+    hashMapImplSetStructure.set(*this, HashMapImpl<HashMapBucket<HashMapBucketDataKey>>::createStructure(*this, 0, jsNull()));
>+    hashMapImplMapStructure.set(*this, HashMapImpl<HashMapBucket<HashMapBucketDataKeyValue>>::createStructure(*this, 0, jsNull()));
> 
>     iterationTerminator.set(*this, JSFinalObject::create(*this, JSFinalObject::createStructure(*this, 0, jsNull(), 1)));
>     nativeStdFunctionCellStructure.set(*this, NativeStdFunctionCell::createStructure(*this, 0, jsNull()));
>Index: Source/JavaScriptCore/runtime/VM.h
>===================================================================
>--- Source/JavaScriptCore/runtime/VM.h	(revision 205305)
>+++ Source/JavaScriptCore/runtime/VM.h	(working copy)
>@@ -331,6 +331,10 @@ public:
>     Strong<Structure> evalCodeBlockStructure;
>     Strong<Structure> functionCodeBlockStructure;
>     Strong<Structure> webAssemblyCodeBlockStructure;
>+    Strong<Structure> hashMapBucketSetStructure;
>+    Strong<Structure> hashMapBucketMapStructure;
>+    Strong<Structure> hashMapImplSetStructure;
>+    Strong<Structure> hashMapImplMapStructure;
> 
>     Strong<JSCell> iterationTerminator;
>     Strong<JSCell> emptyPropertyNameEnumerator;
>Index: Source/WebCore/ChangeLog
>===================================================================
>--- Source/WebCore/ChangeLog	(revision 205305)
>+++ Source/WebCore/ChangeLog	(working copy)
>@@ -1,3 +1,17 @@
>+2016-09-01  Saam Barati  <sbarati@apple.com>
>+
>+        Make JSMap and JSSet faster
>+        https://bugs.webkit.org/show_bug.cgi?id=160989
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        No new tests (OOPS!).
>+
>+        * ForwardingHeaders/runtime/MapBase.h: Added.
>+        * bindings/js/SerializedScriptValue.cpp:
>+        (WebCore::CloneSerializer::serialize):
>+        (WebCore::CloneDeserializer::deserialize):
>+
> 2016-09-01  Alex Christensen  <achristensen@webkit.org>
> 
>         Fix Mac CMake build after r205266.
>Index: Source/WebCore/ForwardingHeaders/runtime/MapBase.h
>===================================================================
>--- Source/WebCore/ForwardingHeaders/runtime/MapBase.h	(nonexistent)
>+++ Source/WebCore/ForwardingHeaders/runtime/MapBase.h	(working copy)
>@@ -0,0 +1,4 @@
>+#ifndef WebCore_FWD_MapBase_h
>+#define WebCore_FWD_MapBase_h
>+#include <JavaScriptCore/MapBase.h>
>+#endif
>Index: Source/WebCore/bindings/js/SerializedScriptValue.cpp
>===================================================================
>--- Source/WebCore/bindings/js/SerializedScriptValue.cpp	(revision 205305)
>+++ Source/WebCore/bindings/js/SerializedScriptValue.cpp	(working copy)
>@@ -1368,7 +1368,7 @@ SerializationReturnCode CloneSerializer:
>             case MapDataStartVisitEntry: {
>                 JSMapIterator* iterator = mapIteratorStack.last();
>                 JSValue key, value;
>-                if (!iterator->nextKeyValue(key, value)) {
>+                if (!iterator->nextKeyValue(m_exec, key, value)) {
>                     mapIteratorStack.removeLast();
>                     JSObject* object = inputObjectStack.last();
>                     ASSERT(jsDynamicCast<JSMap*>(object));
>@@ -2545,7 +2545,9 @@ DeserializationResult CloneDeserializer:
>         mapObjectStartState: {
>             if (outputObjectStack.size() > maximumFilterRecursion)
>                 return std::make_pair(JSValue(), StackOverflowError);
>-            JSMap* map = JSMap::create(m_exec->vm(), m_globalObject->mapStructure());
>+            JSMap* map = JSMap::create(m_exec, m_exec->vm(), m_globalObject->mapStructure());
>+            if (UNLIKELY(m_exec->hadException()))
>+                goto error;
>             m_gcBuffer.append(map);
>             outputObjectStack.append(map);
>             mapStack.append(map);
>@@ -2574,7 +2576,9 @@ DeserializationResult CloneDeserializer:
>         setObjectStartState: {
>             if (outputObjectStack.size() > maximumFilterRecursion)
>                 return std::make_pair(JSValue(), StackOverflowError);
>-            JSSet* set = JSSet::create(m_exec->vm(), m_globalObject->setStructure());
>+            JSSet* set = JSSet::create(m_exec, m_exec->vm(), m_globalObject->setStructure());
>+            if (UNLIKELY(m_exec->hadException()))
>+                goto error;
>             m_gcBuffer.append(set);
>             outputObjectStack.append(set);
>             setStack.append(set);

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Attachments on bug 160989: 286435 | 286517 | 286940 | 286953 | 287064 | 287143 | 287367 | 287466 | 287475 | 287592 | 287687 | 287700 | 287702 | 287714 | 287782 | 287802 | 287803 | 288038 | 288041 | 288057