https://bugs.webkit.org/show_bug.cgi?id=120912

Reviewed by Geoffrey Garen.

Source/JavaScriptCore:

Add support for ES6 WeakMap.  Add the cluster of boilerplate
classes around the core WeakMapData class.

WeakMapData is a simple object->value hash table that uses a
combo of WeakReferenceHarvester to conditionally keep the weak
value reference live, and UnconditionalFinalizer to clean the
dead keys from the table post-GC.

* CMakeLists.txt:
* GNUmakefile.list.am:
* JavaScriptCore.vcxproj/JavaScriptCore.vcxproj:
* JavaScriptCore.vcxproj/JavaScriptCore.vcxproj.filters:
* JavaScriptCore.xcodeproj/project.pbxproj:
* Target.pri:
* runtime/CommonIdentifiers.h:
* runtime/JSGlobalObject.cpp:
* runtime/JSGlobalObject.h:
(JSC::JSGlobalObject::weakMapDataStructure):
* runtime/JSWeakMap.cpp: Added.
(JSC::JSWeakMap::finishCreation):
(JSC::JSWeakMap::visitChildren):
* runtime/JSWeakMap.h: Added.
(JSC::JSWeakMap::createStructure):
(JSC::JSWeakMap::create):
(JSC::JSWeakMap::weakMapData):
(JSC::JSWeakMap::JSWeakMap):
* runtime/WeakMapConstructor.cpp: Added.
(JSC::WeakMapConstructor::finishCreation):
(JSC::constructWeakMap):
(JSC::WeakMapConstructor::getConstructData):
(JSC::WeakMapConstructor::getCallData):
* runtime/WeakMapConstructor.h: Added.
(JSC::WeakMapConstructor::create):
(JSC::WeakMapConstructor::createStructure):
(JSC::WeakMapConstructor::WeakMapConstructor):
* runtime/WeakMapData.cpp: Added.
(JSC::WeakMapData::WeakMapData):
(JSC::WeakMapData::finishCreation):
(JSC::WeakMapData::destroy):
(JSC::WeakMapData::visitChildren):
(JSC::WeakMapData::set):
(JSC::WeakMapData::get):
(JSC::WeakMapData::remove):
(JSC::WeakMapData::contains):
(JSC::WeakMapData::clear):
(JSC::WeakMapData::DeadKeyCleaner::visitWeakReferences):
(JSC::WeakMapData::DeadKeyCleaner::finalizeUnconditionally):
* runtime/WeakMapData.h: Added.
(JSC::WeakMapData::create):
(JSC::WeakMapData::createStructure):
(JSC::WeakMapData::DeadKeyCleaner::DeadKeyCleaner):
* runtime/WeakMapPrototype.cpp: Added.
(JSC::WeakMapPrototype::finishCreation):
(JSC::getWeakMapData):
(JSC::protoFuncWeakMapClear):
(JSC::protoFuncWeakMapDelete):
(JSC::protoFuncWeakMapGet):
(JSC::protoFuncWeakMapHas):
(JSC::protoFuncWeakMapSet):
* runtime/WeakMapPrototype.h: Added.
(JSC::WeakMapPrototype::create):
(JSC::WeakMapPrototype::createStructure):
(JSC::WeakMapPrototype::WeakMapPrototype):

LayoutTests:

Basic tests.

* js/basic-weakmap-expected.txt: Added.
* js/basic-weakmap.html: Added.
* js/script-tests/basic-weakmap.js: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@155473 268f45cc-cd09-0410-ab3c-d52691b4dbfc