Attachment 416418 Details for Bug 212954 – Patch

[patch] Patch

bug-212954-20201217171147.patch (text/plain), 208.85 KB, created by Alexey Shvayka on 2020-12-17 07:11:49 PST

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Creator: Alexey Shvayka

Created: 2020-12-17 07:11:49 PST

Size: 208.85 KB

patch

obsolete

>Index: JSTests/ChangeLog
>===================================================================
>--- JSTests/ChangeLog	(revision 270932)
>+++ JSTests/ChangeLog	(working copy)
>@@ -1,3 +1,20 @@
>+2020-12-17  Alexey Shvayka  <shvaikalesh@gmail.com>
>+
>+        [JSC] Simplify get*PropertyNames() methods and EnumerationMode
>+        https://bugs.webkit.org/show_bug.cgi?id=212954
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * ChakraCore.yaml:
>+        * ChakraCore/test/Basics/enum.baseline-jsc: Removed.
>+        * microbenchmarks/for-in-on-object-with-lazily-materialized-properties.js:
>+        Removed because ErrorInstance no longer materializes properties during for/in enumeration.
>+
>+        * microbenchmarks/object-keys-cloned-arguments.js: Added.
>+        * microbenchmarks/object-keys-error-object.js: Added.
>+        * stress/arguments-properties-order.js: Added.
>+        * stress/for-in-typed-array.js:
>+
> 2020-12-15  Yusuke Suzuki  <ysuzuki@apple.com>
> 
>         [JSC] Accept arbitrary module namespace identifier names
>Index: JSTests/ChakraCore.yaml
>===================================================================
>--- JSTests/ChakraCore.yaml	(revision 270932)
>+++ JSTests/ChakraCore.yaml	(working copy)
>@@ -303,7 +303,7 @@
> - path: ChakraCore/test/Basics/scan.js
>   cmd: runChakra :baseline, "NoException", "scan.baseline-jsc", []
> - path: ChakraCore/test/Basics/enum.js
>-  cmd: runChakra :baseline, "NoException", "enum.baseline-jsc", []
>+  cmd: runChakra :pass, "NoException", "", []
> - path: ChakraCore/test/Basics/with3.js
>   cmd: runChakra :baseline, "NoException", "with3.baseline-jsc", []
> - path: ChakraCore/test/Basics/cross_site_accessor_main.js
>Index: JSTests/ChakraCore/test/Basics/enum.baseline-jsc
>===================================================================
>--- JSTests/ChakraCore/test/Basics/enum.baseline-jsc	(revision 270932)
>+++ JSTests/ChakraCore/test/Basics/enum.baseline-jsc	(nonexistent)
>@@ -1,117 +0,0 @@
>-x:a.x
>-q:a.q
>-u:a.q
>-z:f.p.z
>-r:f.p.r
>-y:o.p.y
>-Object a
>-x
>-y
>-u
>-z
>-Math
>-u
>-x
>-y
>-z
>-Array
>-u
>-x
>-y
>-z
>-Array.prototype
>-u
>-x
>-y
>-z
>-Date
>-u
>-x
>-y
>-z
>-Number
>-u
>-x
>-y
>-z
>-String
>-u
>-x
>-y
>-z
>-Object.prototype
>-u
>-x
>-y
>-z
>-Object
>-u
>-x
>-y
>-z
>-Array.prototype.sort
>-u
>-x
>-y
>-z
>-function foo
>-u
>-x
>-y
>-z
>-x
>-u
>-y
>-z
>-me here
>-prototype chain
>-u
>-x
>-y
>-z
>-Literal String
>-0
>-1
>-2
>-3
>-4
>-5
>-6
>-7
>-8
>-9
>-zz
>-u
>-x
>-y
>-z
>-String Object
>-xx
>-yy
>-0
>-1
>-2
>-3
>-4
>-5
>-6
>-7
>-8
>-9
>-10
>-11
>-zz
>-u
>-x
>-y
>-z
>-5
>-u
>-x
>-y
>-z
>-3
>-u
>-x
>-y
>-z
>Index: JSTests/microbenchmarks/for-in-on-object-with-lazily-materialized-properties.js
>===================================================================
>--- JSTests/microbenchmarks/for-in-on-object-with-lazily-materialized-properties.js	(revision 270932)
>+++ JSTests/microbenchmarks/for-in-on-object-with-lazily-materialized-properties.js	(nonexistent)
>@@ -1,15 +0,0 @@
>-//@ skip if $model == "Apple Watch Series 3" # added by mark-jsc-stress-test.py
>-function foo(o) {
>-    var count = 0;
>-    for (var p in o) {
>-        if (o[p])
>-            count ++;
>-    }
>-    return count;
>-}
>-noInline(foo);
>-
>-var total = 0;
>-for (let j = 0; j < 100000; ++j)
>-    total += foo(new Error);
>-
>Index: JSTests/microbenchmarks/object-keys-cloned-arguments.js
>===================================================================
>--- JSTests/microbenchmarks/object-keys-cloned-arguments.js	(nonexistent)
>+++ JSTests/microbenchmarks/object-keys-cloned-arguments.js	(working copy)
>@@ -0,0 +1,9 @@
>+noInline(Object.keys);
>+
>+function getArgs(a, b, c) {
>+    "use strict";
>+    return arguments;
>+}
>+
>+for (var i = 0; i < 2e5; ++i)
>+    Object.keys(getArgs(1, 2, 3));
>Index: JSTests/microbenchmarks/object-keys-error-object.js
>===================================================================
>--- JSTests/microbenchmarks/object-keys-error-object.js	(nonexistent)
>+++ JSTests/microbenchmarks/object-keys-error-object.js	(working copy)
>@@ -0,0 +1,4 @@
>+noInline(Object.keys);
>+
>+for (var i = 0; i < 2e5; ++i)
>+    Object.keys(new Error());
>Index: JSTests/stress/arguments-properties-order.js
>===================================================================
>--- JSTests/stress/arguments-properties-order.js	(nonexistent)
>+++ JSTests/stress/arguments-properties-order.js	(working copy)
>@@ -0,0 +1,79 @@
>+function getMappedArguments(a, b) { return arguments; }
>+function getUnmappedArguments(a, b) { "use strict"; return arguments; }
>+
>+function shouldBeArray(actual, expected) {
>+    var isEqual =
>+        actual.length === expected.length &&
>+        actual.every((item, index) => item === expected[index]);
>+    if (!isEqual)
>+        throw new Error(`Expected [${actual.map(String)}] to equal [${expected.map(String)}]`);
>+}
>+
>+function forIn(object) {
>+    var keys = [];
>+    for (var key in object)
>+        keys.push(key);
>+    return keys;
>+}
>+
>+noInline(getMappedArguments);
>+noInline(getUnmappedArguments);
>+noInline(forIn);
>+
>+(function() {
>+    for (var i = 0; i < 1e4; ++i) {
>+        var mappedArguments = getMappedArguments(0, 1, 2);
>+        shouldBeArray(forIn(mappedArguments), ["0", "1", "2"]);
>+        shouldBeArray(Object.keys(mappedArguments), ["0", "1", "2"]);
>+        shouldBeArray(Reflect.ownKeys(mappedArguments), ["0", "1", "2", "length", "callee", Symbol.iterator]);
>+
>+        var unmappedArguments = getUnmappedArguments(0);
>+        shouldBeArray(forIn(unmappedArguments), ["0"]);
>+        shouldBeArray(Object.keys(unmappedArguments), ["0"]);
>+        shouldBeArray(Reflect.ownKeys(unmappedArguments), ["0", "length", "callee", Symbol.iterator]);
>+    }
>+})();
>+
>+(function() {
>+    for (var i = 0; i < 1e4; ++i) {
>+        var mappedArguments = getMappedArguments(0, 1);
>+        mappedArguments[8] = 8;
>+        mappedArguments[2] = 2;
>+        shouldBeArray(forIn(mappedArguments), ["0", "1", "2", "8"]);
>+        shouldBeArray(Object.keys(mappedArguments), ["0", "1", "2", "8"]);
>+        shouldBeArray(Reflect.ownKeys(mappedArguments), ["0", "1", "2", "8", "length", "callee", Symbol.iterator]);
>+
>+        var unmappedArguments = getUnmappedArguments();
>+        unmappedArguments[12] = 12;
>+        unmappedArguments[3] = 3;
>+        shouldBeArray(forIn(unmappedArguments), ["3", "12"]);
>+        shouldBeArray(Object.keys(unmappedArguments), ["3", "12"]);
>+        shouldBeArray(Reflect.ownKeys(unmappedArguments), ["3", "12", "length", "callee", Symbol.iterator]);
>+    }
>+})();
>+
>+(function() {
>+    for (var i = 0; i < 1e4; ++i) {
>+        var mappedArguments = getMappedArguments(0);
>+        mappedArguments.foo = 1;
>+        mappedArguments.bar = 2;
>+        shouldBeArray(forIn(mappedArguments), ["0", "foo", "bar"]);
>+        shouldBeArray(Object.keys(mappedArguments), ["0", "foo", "bar"]);
>+        // FIXME: Symbol.iterator should come after "foo" and "bar" 
>+        // shouldBeArray(Reflect.ownKeys(mappedArguments), ["0", "length", "callee", "foo", "bar", Symbol.iterator]);
>+
>+        var unmappedArguments = getUnmappedArguments(0, 1, 2);
>+        unmappedArguments.foo = 1;
>+        unmappedArguments.bar = 2;
>+        shouldBeArray(forIn(unmappedArguments), ["0", "1", "2", "foo", "bar"]);
>+        shouldBeArray(Object.keys(unmappedArguments), ["0", "1", "2", "foo", "bar"]);
>+        // FIXME: "callee" should come before "foo" and "bar"
>+        // shouldBeArray(Reflect.ownKeys(unmappedArguments), ["0", "1", "2", "length", "callee", "foo", "bar", Symbol.iterator]);
>+    }
>+})();
>+
>+// FIXME: Add more tests, covering:
>+// * added symbol properties;
>+// * added together index, non-index, and symbol properties;
>+// * deleted, re-added, and redefined as DontEnum index properties, both within and beyond "length";
>+// * deleted, re-added, and redefined as DontEnum "length", "callee", and Symbol.iterator properties.
>Index: JSTests/stress/for-in-typed-array.js
>===================================================================
>--- JSTests/stress/for-in-typed-array.js	(revision 270932)
>+++ JSTests/stress/for-in-typed-array.js	(working copy)
>@@ -16,3 +16,25 @@
>     }
>     foo(null);
> })();
>+
>+(function() {
>+    function forIn() {
>+        var a = new Int32Array(4);
>+        a.foo = 1;
>+        a.bar = 2;
>+        for (var i = 0; i < a.length; ++i)
>+            a[i] = i;
>+
>+        var keys = [];
>+        for (var k in a)
>+            keys.push(k);
>+        return keys.join("|");
>+    }
>+    noInline(forIn);
>+
>+    for (var i = 0; i < 1e4; ++i) {
>+        var keys = forIn();
>+        if (keys !== "0|1|2|3|foo|bar")
>+            throw new Error(`Bad result: ${keys}`);
>+    }
>+})();
>Index: Source/JavaScriptCore/ChangeLog
>===================================================================
>--- Source/JavaScriptCore/ChangeLog	(revision 270932)
>+++ Source/JavaScriptCore/ChangeLog	(working copy)
>@@ -1,3 +1,219 @@
>+2020-12-17  Alexey Shvayka  <shvaikalesh@gmail.com>
>+
>+        [JSC] Simplify get*PropertyNames() methods and EnumerationMode
>+        https://bugs.webkit.org/show_bug.cgi?id=212954
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        Before this change, [[OwnPropertyKeys]] overrides were sometimes implemented
>+        inconsistently, via different get*PropertyNames() methods that duplicated logic
>+        (e.g. ErrorInstance, RegExpObject, and StringObject).
>+
>+        This patch:
>+
>+        1. Introduces a clear convention to implement [[OwnPropertyKeys]] overrides:
>+           if it's defined by the spec, getOwnPropertyNames() method is used; otherwise,
>+           non-materialized properties are enumerated / reified in getOwnSpecialPropertyNames().
>+           While no class should define both methods, we don't assert this to support inheritance.
>+
>+           Removes getOwnNonIndexPropertyNames() from the method table and converts it to instance
>+           method; its overrides were renamed to getOwnSpecialPropertyNames() and exempted from
>+           calling the no-op base method.
>+
>+           This approach was chosen, instead of getOwnNonIndexPropertyNames() override, because
>+           for/in enumeration must be sure there are no enumerable properties between
>+           getEnumerableLength() and the first structure property.
>+
>+           Also, removes getStructurePropertyNames() from the method table as it's unreasonable
>+           to override it.
>+
>+        2. Extracts JSObject::getOwnIndexPropertyNames() instance method to enforce
>+           correct enumeration order in getOwnPropertyNames() overrides: special indices =>
>+           butterfly storage => special properties => non-reified static => structure properties.
>+
>+           Loose mode `arguments` were fixed to enumerate indices from butterfly storage before
>+           special properties [1], aligning JSC with V8 and SpiderMonkey.
>+
>+        3. Reworks for/in enumeration so the special properties always come before structure ones,
>+           aligning enumeration order of String objects [2] and typed arrays [3] that have expando
>+           properties with the spec, V8, and SpiderMonkey.
>+
>+           Removes getPropertyNames() and getGenericPropertyNames() from the method table, along
>+           with their overrides, because ES7 disabled customization of for/in enumeration [4].
>+           Instead, JSObject::getPropertyNames() instance method and getEnumerablePropertyNames()
>+           are introduced, featuring a loop instead of recursion.
>+
>+           Also, this enabled dropping hard-to-follow JSObjectPropertiesMode bit and simplifying
>+           EnumerationMode to an enum.
>+
>+        for/in and Object.keys microbenchmarks are neutral. This change does not affect
>+        JSPropertyNameEnumerator caching, nor fast paths of its bytecodes.
>+
>+        [1]: https://tc39.es/ecma262/#sec-createmappedargumentsobject (steps 15-16 and 20-21)
>+        [2]: https://tc39.es/ecma262/#sec-string-exotic-objects-ownpropertykeys
>+        [3]: https://tc39.es/ecma262/#sec-integer-indexed-exotic-objects-ownpropertykeys
>+        [4]: https://github.com/tc39/ecma262/pull/367
>+
>+        * API/JSAPIValueWrapper.h:
>+        Remove OverridesAnyFormOfGetPropertyNames structure flag as it should never be queried
>+        from JSCell instances.
>+
>+        * API/JSCallbackObject.h:
>+        * API/JSCallbackObjectFunctions.h:
>+        (JSC::JSCallbackObject<Parent>::getOwnSpecialPropertyNames):
>+        (JSC::JSCallbackObject<Parent>::getOwnNonIndexPropertyNames): Deleted.
>+        * API/JSObjectRef.cpp:
>+        (JSObjectCopyPropertyNames):
>+        * bindings/ScriptValue.cpp:
>+        (Inspector::jsToInspectorValue):
>+        * bytecode/ObjectAllocationProfileInlines.h:
>+        (JSC::ObjectAllocationProfileBase<Derived>::possibleDefaultPropertyCount):
>+        Use DontEnumPropertyMode::Include as the intent is to count all properties, even
>+        private symbols. EnumerationMode() defaults did exclude non-enumerable properties.
>+
>+        * debugger/DebuggerScope.cpp:
>+        (JSC::DebuggerScope::getOwnPropertyNames):
>+        * debugger/DebuggerScope.h:
>+        * runtime/ClassInfo.h:
>+        * runtime/ClonedArguments.cpp:
>+        (JSC::ClonedArguments::getOwnSpecialPropertyNames):
>+        Don't materialize DontEnum properties unless it's DontEnumPropertiesMode::Include,
>+        advancing provided microbenchmark by ~23%.
>+
>+        (JSC::ClonedArguments::getOwnPropertyNames): Deleted.
>+        * runtime/ClonedArguments.h:
>+        * runtime/EnumerationMode.h:
>+        Explicitly specify enum type to reduce its size.
>+
>+        (JSC::EnumerationMode::EnumerationMode): Deleted.
>+        (JSC::EnumerationMode::includeDontEnumProperties): Deleted.
>+        (JSC::EnumerationMode::includeJSObjectProperties): Deleted.
>+        * runtime/ErrorInstance.cpp:
>+        (JSC::ErrorInstance::getOwnSpecialPropertyNames):
>+        Don't materialize DontEnum properties unless it's DontEnumPropertiesMode::Include,
>+        advancing provided microbenchmark by a factor of 5.
>+
>+        (JSC::ErrorInstance::getOwnNonIndexPropertyNames): Deleted.
>+        (JSC::ErrorInstance::getStructurePropertyNames): Deleted.
>+        * runtime/ErrorInstance.h:
>+        * runtime/GenericArguments.h:
>+        * runtime/GenericArgumentsInlines.h:
>+        (JSC::GenericArguments<Type>::getOwnPropertyNames):
>+        * runtime/JSArray.cpp:
>+        (JSC::JSArray::getOwnSpecialPropertyNames):
>+        (JSC::JSArray::getOwnNonIndexPropertyNames): Deleted.
>+        * runtime/JSArray.h:
>+        * runtime/JSCell.cpp:
>+        (JSC::JSCell::getOwnPropertyNames):
>+        (JSC::JSCell::getOwnSpecialPropertyNames):
>+        (JSC::JSCell::getOwnNonIndexPropertyNames): Deleted.
>+        (JSC::JSCell::getPropertyNames): Deleted.
>+        (JSC::JSCell::getStructurePropertyNames): Deleted.
>+        (JSC::JSCell::getGenericPropertyNames): Deleted.
>+        * runtime/JSCell.h:
>+        * runtime/JSFunction.cpp:
>+        (JSC::JSFunction::getOwnSpecialPropertyNames):
>+        (JSC::JSFunction::getOwnNonIndexPropertyNames): Deleted.
>+        * runtime/JSFunction.h:
>+        * runtime/JSGenericTypedArrayView.h:
>+        * runtime/JSGenericTypedArrayViewInlines.h:
>+        (JSC::JSGenericTypedArrayView<Adaptor>::getOwnPropertyNames):
>+        * runtime/JSGlobalObject.h:
>+        Remove OverridesAnyFormOfGetPropertyNames structure flag as it's inherited from
>+        JSSymbolTableObject, and JSGlobalObject itself doesn't override getOwn*PropertyNames().
>+
>+        * runtime/JSLexicalEnvironment.cpp:
>+        (JSC::JSLexicalEnvironment::getOwnSpecialPropertyNames):
>+        (JSC::JSLexicalEnvironment::getOwnNonIndexPropertyNames): Deleted.
>+        * runtime/JSLexicalEnvironment.h:
>+        * runtime/JSModuleEnvironment.cpp:
>+        (JSC::JSModuleEnvironment::getOwnSpecialPropertyNames):
>+        (JSC::JSModuleEnvironment::getOwnNonIndexPropertyNames): Deleted.
>+        * runtime/JSModuleEnvironment.h:
>+        * runtime/JSModuleNamespaceObject.cpp:
>+        (JSC::JSModuleNamespaceObject::getOwnPropertyNames):
>+        Call getOwnNonIndexPropertyNames() directly, guarded by includeSymbolProperties() check,
>+        since module namespace objects can't have string properties besides m_names.
>+        (See https://tc39.es/ecma262/#sec-module-namespace-exotic-objects-defineownproperty-p-desc)
>+
>+        * runtime/JSModuleNamespaceObject.h:
>+        * runtime/JSONObject.cpp:
>+        (JSC::Stringifier::Holder::appendNextProperty):
>+        (JSC::Walker::walk):
>+        * runtime/JSObject.cpp:
>+        (JSC::JSObject::getNonReifiedStaticPropertyNames):
>+        (JSC::JSObject::getPropertyNames):
>+        (JSC::JSObject::getOwnPropertyNames):
>+        (JSC::JSObject::getOwnSpecialPropertyNames):
>+        (JSC::JSObject::getOwnIndexedPropertyNames):
>+        (JSC::JSObject::getOwnNonIndexPropertyNames):
>+        (JSC::getClassPropertyNames): Deleted.
>+        (JSC::JSObject::getStructurePropertyNames): Deleted.
>+        (JSC::JSObject::getGenericPropertyNames): Deleted.
>+        * runtime/JSObject.h:
>+        (JSC::JSObject::getOwnSpecialPropertyNames):
>+        * runtime/JSPropertyNameEnumerator.cpp:
>+        (JSC::getEnumerablePropertyNames):
>+        * runtime/JSPropertyNameEnumerator.h:
>+        (JSC::propertyNameEnumerator):
>+        * runtime/JSProxy.cpp:
>+        (JSC::JSProxy::getOwnPropertyNames):
>+        (JSC::JSProxy::getPropertyNames): Deleted.
>+        (JSC::JSProxy::getStructurePropertyNames): Deleted.
>+        (JSC::JSProxy::getGenericPropertyNames): Deleted.
>+        * runtime/JSProxy.h:
>+        * runtime/JSSymbolTableObject.cpp:
>+        (JSC::JSSymbolTableObject::getOwnSpecialPropertyNames):
>+        (JSC::JSSymbolTableObject::getOwnNonIndexPropertyNames): Deleted.
>+        * runtime/JSSymbolTableObject.h:
>+        * runtime/JSTypeInfo.h:
>+        (JSC::TypeInfo::overridesGetOwnPropertyNames const):
>+        (JSC::TypeInfo::overridesGetOwnSpecialPropertyNames const):
>+        (JSC::TypeInfo::overridesAnyFormOfGetOwnPropertyNames const):
>+        (JSC::TypeInfo::overridesGetPropertyNames const): Deleted.
>+        (JSC::TypeInfo::overridesAnyFormOfGetPropertyNames const): Deleted.
>+        * runtime/ObjectConstructor.cpp:
>+        (JSC::objectConstructorGetOwnPropertyDescriptors):
>+        (JSC::JSC_DEFINE_HOST_FUNCTION):
>+        (JSC::defineProperties):
>+        (JSC::setIntegrityLevel):
>+        (JSC::testIntegrityLevel):
>+        (JSC::ownPropertyKeys):
>+        * runtime/ProxyObject.cpp:
>+        (JSC::ProxyObject::performGetOwnPropertyNames):
>+        (JSC::ProxyObject::getOwnPropertyNames):
>+        (JSC::ProxyObject::getPropertyNames): Deleted.
>+        (JSC::ProxyObject::getOwnNonIndexPropertyNames): Deleted.
>+        (JSC::ProxyObject::getStructurePropertyNames): Deleted.
>+        (JSC::ProxyObject::getGenericPropertyNames): Deleted.
>+        * runtime/ProxyObject.h:
>+        Remove IsQuickPropertyAccessAllowedForEnumeration flag from ProxyObject's structure
>+        since canAccessPropertiesQuicklyForEnumeration() now checks for method overrides.
>+
>+        * runtime/RegExpObject.cpp:
>+        (JSC::RegExpObject::getOwnSpecialPropertyNames):
>+        (JSC::RegExpObject::getOwnNonIndexPropertyNames): Deleted.
>+        (JSC::RegExpObject::getPropertyNames): Deleted.
>+        (JSC::RegExpObject::getGenericPropertyNames): Deleted.
>+        * runtime/RegExpObject.h:
>+        * runtime/StringObject.cpp:
>+        (JSC::StringObject::getOwnPropertyNames):
>+        (JSC::StringObject::getOwnNonIndexPropertyNames): Deleted.
>+        * runtime/StringObject.h:
>+        * runtime/Structure.cpp:
>+        (JSC::Structure::validateFlags):
>+        Strengthen overridesGetOwn*PropertyNames and overridesGetPrototype asserts into
>+        equivalence tests.
>+
>+        (JSC::Structure::getPropertyNamesFromStructure):
>+        (JSC::Structure::canAccessPropertiesQuicklyForEnumeration const):
>+        * runtime/Structure.h:
>+        * runtime/StructureInlines.h:
>+        (JSC::Structure::canCacheOwnPropertyNames const):
>+        * tools/JSDollarVM.cpp:
>+        Remove OverridesAnyFormOfGetPropertyNames structure flag as it's inherited from
>+        JSArray, and RuntimeArray itself doesn't override getOwn*PropertyNames().
>+
> 2020-12-16  Yusuke Suzuki  <ysuzuki@apple.com>
> 
>         [JSC] Not using JITCage trampoline for non JITCage JSC
>Index: Source/JavaScriptCore/API/JSAPIValueWrapper.h
>===================================================================
>--- Source/JavaScriptCore/API/JSAPIValueWrapper.h	(revision 270932)
>+++ Source/JavaScriptCore/API/JSAPIValueWrapper.h	(working copy)
>@@ -33,13 +33,7 @@ class JSAPIValueWrapper final : public J
>     friend JSValue jsAPIValueWrapper(JSGlobalObject*, JSValue);
> public:
>     using Base = JSCell;
>-
>-    // OverridesAnyFormOfGetPropertyNames (which used to be OverridesGetPropertyNames) was here
>-    // since ancient times back when we pessimistically choose to apply this flag. I think we
>-    // can remove it, but we should do more testing before we do so.
>-    // Ref: http://trac.webkit.org/changeset/49694/webkit#file9
>-    // FIXME: https://bugs.webkit.org/show_bug.cgi?id=212954
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesAnyFormOfGetPropertyNames | StructureIsImmortal;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal;
> 
>     template<typename CellType, SubspaceAccess mode>
>     static IsoSubspace* subspaceFor(VM& vm)
>Index: Source/JavaScriptCore/API/JSCallbackObject.h
>===================================================================
>--- Source/JavaScriptCore/API/JSCallbackObject.h	(revision 270932)
>+++ Source/JavaScriptCore/API/JSCallbackObject.h	(working copy)
>@@ -125,7 +125,7 @@ template <class Parent>
> class JSCallbackObject final : public Parent {
> public:
>     using Base = Parent;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | ProhibitsPropertyCaching | OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | ImplementsHasInstance | OverridesAnyFormOfGetPropertyNames | OverridesGetCallData;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnSpecialPropertyNames | OverridesGetCallData | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | ImplementsHasInstance | ProhibitsPropertyCaching;
>     static_assert(!(StructureFlags & ImplementsDefaultHasInstance), "using customHasInstance");
> 
>     ~JSCallbackObject();
>@@ -211,7 +211,7 @@ private:
> 
>     static bool customHasInstance(JSObject*, JSGlobalObject*, JSValue);
> 
>-    static void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
> 
>     static CallData getConstructData(JSCell*);
>     static CallData getCallData(JSCell*);
>Index: Source/JavaScriptCore/API/JSCallbackObjectFunctions.h
>===================================================================
>--- Source/JavaScriptCore/API/JSCallbackObjectFunctions.h	(revision 270932)
>+++ Source/JavaScriptCore/API/JSCallbackObjectFunctions.h	(working copy)
>@@ -569,7 +569,7 @@ EncodedJSValue JSCallbackObject<Parent>:
> }
> 
> template <class Parent>
>-void JSCallbackObject<Parent>::getOwnNonIndexPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSCallbackObject<Parent>::getOwnSpecialPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = getVM(globalObject);
>     JSCallbackObject* thisObject = jsCast<JSCallbackObject*>(object);
>@@ -588,7 +588,7 @@ void JSCallbackObject<Parent>::getOwnNon
>             for (iterator it = staticValues->begin(); it != end; ++it) {
>                 StringImpl* name = it->key.get();
>                 StaticValueEntry* entry = it->value.get();
>-                if (entry->getProperty && (!(entry->attributes & kJSPropertyAttributeDontEnum) || mode.includeDontEnumProperties())) {
>+                if (entry->getProperty && (mode == DontEnumPropertiesMode::Include || !(entry->attributes & kJSPropertyAttributeDontEnum))) {
>                     ASSERT(!name->isSymbol());
>                     propertyNames.add(Identifier::fromString(vm, String(name)));
>                 }
>@@ -601,15 +601,13 @@ void JSCallbackObject<Parent>::getOwnNon
>             for (iterator it = staticFunctions->begin(); it != end; ++it) {
>                 StringImpl* name = it->key.get();
>                 StaticFunctionEntry* entry = it->value.get();
>-                if (!(entry->attributes & kJSPropertyAttributeDontEnum) || mode.includeDontEnumProperties()) {
>+                if (mode == DontEnumPropertiesMode::Include || !(entry->attributes & kJSPropertyAttributeDontEnum)) {
>                     ASSERT(!name->isSymbol());
>                     propertyNames.add(Identifier::fromString(vm, String(name)));
>                 }
>             }
>         }
>     }
>-    
>-    Parent::getOwnNonIndexPropertyNames(thisObject, globalObject, propertyNames, mode);
> }
> 
> template <class Parent>
>Index: Source/JavaScriptCore/API/JSObjectRef.cpp
>===================================================================
>--- Source/JavaScriptCore/API/JSObjectRef.cpp	(revision 270932)
>+++ Source/JavaScriptCore/API/JSObjectRef.cpp	(working copy)
>@@ -808,7 +808,7 @@ JSPropertyNameArrayRef JSObjectCopyPrope
>     JSObject* jsObject = toJS(object);
>     JSPropertyNameArrayRef propertyNames = new OpaqueJSPropertyNameArray(&vm);
>     PropertyNameArray array(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
>-    jsObject->methodTable(vm)->getPropertyNames(jsObject, globalObject, array, EnumerationMode());
>+    jsObject->getPropertyNames(globalObject, array, DontEnumPropertiesMode::Exclude);
> 
>     size_t size = array.size();
>     propertyNames->array.reserveInitialCapacity(size);
>Index: Source/JavaScriptCore/bindings/ScriptValue.cpp
>===================================================================
>--- Source/JavaScriptCore/bindings/ScriptValue.cpp	(revision 270932)
>+++ Source/JavaScriptCore/bindings/ScriptValue.cpp	(working copy)
>@@ -77,7 +77,7 @@ static RefPtr<JSON::Value> jsToInspector
>         auto inspectorObject = JSON::Object::create();
>         auto& object = *value.getObject();
>         PropertyNameArray propertyNames(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
>-        object.methodTable(vm)->getOwnPropertyNames(&object, globalObject, propertyNames, EnumerationMode());
>+        object.methodTable(vm)->getOwnPropertyNames(&object, globalObject, propertyNames, DontEnumPropertiesMode::Exclude);
>         for (auto& name : propertyNames) {
>             auto inspectorValue = jsToInspectorValue(globalObject, object.get(globalObject, name), maxDepth);
>             if (!inspectorValue)
>Index: Source/JavaScriptCore/bytecode/ObjectAllocationProfileInlines.h
>===================================================================
>--- Source/JavaScriptCore/bytecode/ObjectAllocationProfileInlines.h	(revision 270932)
>+++ Source/JavaScriptCore/bytecode/ObjectAllocationProfileInlines.h	(working copy)
>@@ -147,7 +147,7 @@ ALWAYS_INLINE unsigned ObjectAllocationP
> 
>     size_t count = 0;
>     PropertyNameArray propertyNameArray(vm, PropertyNameMode::StringsAndSymbols, PrivateSymbolMode::Include);
>-    prototype->structure(vm)->getPropertyNamesFromStructure(vm, propertyNameArray, EnumerationMode());
>+    prototype->structure(vm)->getPropertyNamesFromStructure(vm, propertyNameArray, DontEnumPropertiesMode::Include);
>     PropertyNameArrayData::PropertyNameVector& propertyNameVector = propertyNameArray.data()->propertyNameVector();
>     for (size_t i = 0; i < propertyNameVector.size(); ++i) {
>         JSValue value = prototype->getDirect(vm, propertyNameVector[i]);
>Index: Source/JavaScriptCore/debugger/DebuggerScope.cpp
>===================================================================
>--- Source/JavaScriptCore/debugger/DebuggerScope.cpp	(revision 270932)
>+++ Source/JavaScriptCore/debugger/DebuggerScope.cpp	(working copy)
>@@ -138,14 +138,14 @@ bool DebuggerScope::deleteProperty(JSCel
>     return thisObject->methodTable(globalObject->vm())->deleteProperty(thisObject, globalObject, propertyName, slot);
> }
> 
>-void DebuggerScope::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void DebuggerScope::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     DebuggerScope* scope = jsCast<DebuggerScope*>(object);
>     ASSERT(scope->isValid());
>     if (!scope->isValid())
>         return;
>     JSObject* thisObject = JSScope::objectAtScope(scope->jsScope());
>-    thisObject->methodTable(globalObject->vm())->getPropertyNames(thisObject, globalObject, propertyNames, mode);
>+    thisObject->getPropertyNames(globalObject, propertyNames, mode);
> }
> 
> bool DebuggerScope::defineOwnProperty(JSObject* object, JSGlobalObject* globalObject, PropertyName propertyName, const PropertyDescriptor& descriptor, bool shouldThrow)
>Index: Source/JavaScriptCore/debugger/DebuggerScope.h
>===================================================================
>--- Source/JavaScriptCore/debugger/DebuggerScope.h	(revision 270932)
>+++ Source/JavaScriptCore/debugger/DebuggerScope.h	(working copy)
>@@ -36,7 +36,7 @@ class JSScope;
> class DebuggerScope final : public JSNonFinalObject {
> public:
>     using Base = JSNonFinalObject;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnPropertyNames;
> 
>     template<typename CellType, SubspaceAccess mode>
>     static IsoSubspace* subspaceFor(VM& vm)
>@@ -52,7 +52,7 @@ public:
>     static bool getOwnPropertySlot(JSObject*, JSGlobalObject*, PropertyName, PropertySlot&);
>     static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
>     static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
>-    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     static bool defineOwnProperty(JSObject*, JSGlobalObject*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
> 
>     DECLARE_EXPORT_INFO;
>Index: Source/JavaScriptCore/runtime/ClassInfo.h
>===================================================================
>--- Source/JavaScriptCore/runtime/ClassInfo.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/ClassInfo.h	(working copy)
>@@ -80,21 +80,13 @@ struct MethodTable {
>     using DefaultValueFunctionPtr = JSValue (*)(const JSObject*, JSGlobalObject*, PreferredPrimitiveType);
>     DefaultValueFunctionPtr METHOD_TABLE_ENTRY(defaultValue);
> 
>-    using GetOwnPropertyNamesFunctionPtr = void (*)(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    using GetOwnPropertyNamesFunctionPtr = void (*)(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     GetOwnPropertyNamesFunctionPtr METHOD_TABLE_ENTRY(getOwnPropertyNames);
>-
>-    using GetOwnNonIndexPropertyNamesFunctionPtr = void (*)(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    GetOwnNonIndexPropertyNamesFunctionPtr METHOD_TABLE_ENTRY(getOwnNonIndexPropertyNames);
>-
>-    using GetPropertyNamesFunctionPtr = void (*)(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    GetPropertyNamesFunctionPtr METHOD_TABLE_ENTRY(getPropertyNames);
>+    GetOwnPropertyNamesFunctionPtr METHOD_TABLE_ENTRY(getOwnSpecialPropertyNames);
> 
>     using GetEnumerableLengthFunctionPtr = uint32_t (*)(JSGlobalObject*, JSObject*);
>     GetEnumerableLengthFunctionPtr METHOD_TABLE_ENTRY(getEnumerableLength);
> 
>-    GetPropertyNamesFunctionPtr METHOD_TABLE_ENTRY(getStructurePropertyNames);
>-    GetPropertyNamesFunctionPtr METHOD_TABLE_ENTRY(getGenericPropertyNames);
>-
>     using ClassNameFunctionPtr = String (*)(const JSObject*, VM&);
>     ClassNameFunctionPtr METHOD_TABLE_ENTRY(className);
> 
>@@ -168,11 +160,8 @@ struct MethodTable {
>         &ClassName::toThis, \
>         &ClassName::defaultValue, \
>         &ClassName::getOwnPropertyNames, \
>-        &ClassName::getOwnNonIndexPropertyNames, \
>-        &ClassName::getPropertyNames, \
>+        &ClassName::getOwnSpecialPropertyNames, \
>         &ClassName::getEnumerableLength, \
>-        &ClassName::getStructurePropertyNames, \
>-        &ClassName::getGenericPropertyNames, \
>         &ClassName::className, \
>         &ClassName::toStringName, \
>         &ClassName::customHasInstance, \
>Index: Source/JavaScriptCore/runtime/ClonedArguments.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/ClonedArguments.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/ClonedArguments.cpp	(working copy)
>@@ -197,11 +197,11 @@ bool ClonedArguments::getOwnPropertySlot
>     return Base::getOwnPropertySlot(thisObject, globalObject, ident, slot);
> }
> 
>-void ClonedArguments::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& array, EnumerationMode mode)
>+void ClonedArguments::getOwnSpecialPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray&, DontEnumPropertiesMode mode)
> {
>     ClonedArguments* thisObject = jsCast<ClonedArguments*>(object);
>-    thisObject->materializeSpecialsIfNecessary(globalObject);
>-    Base::getOwnPropertyNames(thisObject, globalObject, array, mode);
>+    if (mode == DontEnumPropertiesMode::Include)
>+        thisObject->materializeSpecialsIfNecessary(globalObject);
> }
> 
> bool ClonedArguments::put(JSCell* cell, JSGlobalObject* globalObject, PropertyName ident, JSValue value, PutPropertySlot& slot)
>Index: Source/JavaScriptCore/runtime/ClonedArguments.h
>===================================================================
>--- Source/JavaScriptCore/runtime/ClonedArguments.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/ClonedArguments.h	(working copy)
>@@ -40,7 +40,7 @@ namespace JSC {
> class ClonedArguments final : public JSNonFinalObject {
> public:
>     using Base = JSNonFinalObject;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnSpecialPropertyNames;
> 
>     template<typename CellType, SubspaceAccess mode>
>     static IsoSubspace* subspaceFor(VM& vm)
>@@ -70,7 +70,7 @@ private:
>     static Structure* createStructure(VM&, JSGlobalObject*, JSValue prototype, IndexingType);
> 
>     static bool getOwnPropertySlot(JSObject*, JSGlobalObject*, PropertyName, PropertySlot&);
>-    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
>     static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
>     static bool defineOwnProperty(JSObject*, JSGlobalObject*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
>Index: Source/JavaScriptCore/runtime/EnumerationMode.h
>===================================================================
>--- Source/JavaScriptCore/runtime/EnumerationMode.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/EnumerationMode.h	(working copy)
>@@ -27,56 +27,20 @@
> 
> namespace JSC {
> 
>-enum class PropertyNameMode {
>+enum class PropertyNameMode : uint8_t {
>     Symbols = 1 << 0,
>     Strings = 1 << 1,
>     StringsAndSymbols = Symbols | Strings,
> };
> 
>-enum class PrivateSymbolMode {
>+enum class PrivateSymbolMode : uint8_t {
>     Include,
>     Exclude
> };
> 
>-enum class DontEnumPropertiesMode {
>+enum class DontEnumPropertiesMode : uint8_t {
>     Include,
>     Exclude
> };
> 
>-enum class JSObjectPropertiesMode {
>-    Include,
>-    Exclude
>-};
>-
>-class EnumerationMode {
>-public:
>-    EnumerationMode(DontEnumPropertiesMode dontEnumPropertiesMode = DontEnumPropertiesMode::Exclude, JSObjectPropertiesMode jsObjectPropertiesMode = JSObjectPropertiesMode::Include)
>-        : m_dontEnumPropertiesMode(dontEnumPropertiesMode)
>-        , m_jsObjectPropertiesMode(jsObjectPropertiesMode)
>-    {
>-    }
>-
>-    EnumerationMode(const EnumerationMode& mode, JSObjectPropertiesMode jsObjectPropertiesMode)
>-        : m_dontEnumPropertiesMode(mode.m_dontEnumPropertiesMode)
>-        , m_jsObjectPropertiesMode(jsObjectPropertiesMode)
>-    {
>-    }
>-
>-    // Add other constructors as needed for convenience
>-
>-    bool includeDontEnumProperties()
>-    {
>-        return m_dontEnumPropertiesMode == DontEnumPropertiesMode::Include;
>-    }
>-
>-    bool includeJSObjectProperties()
>-    {
>-        return m_jsObjectPropertiesMode == JSObjectPropertiesMode::Include;
>-    }
>-
>-private:
>-    DontEnumPropertiesMode m_dontEnumPropertiesMode;
>-    JSObjectPropertiesMode m_jsObjectPropertiesMode;
>-};
>-
> } // namespace JSC
>Index: Source/JavaScriptCore/runtime/ErrorInstance.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/ErrorInstance.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/ErrorInstance.cpp	(working copy)
>@@ -260,20 +260,12 @@ bool ErrorInstance::getOwnPropertySlot(J
>     return Base::getOwnPropertySlot(thisObject, globalObject, propertyName, slot);
> }
> 
>-void ErrorInstance::getOwnNonIndexPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNameArray, EnumerationMode enumerationMode)
>+void ErrorInstance::getOwnSpecialPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray&, DontEnumPropertiesMode mode)
> {
>     VM& vm = globalObject->vm();
>     ErrorInstance* thisObject = jsCast<ErrorInstance*>(object);
>-    thisObject->materializeErrorInfoIfNeeded(vm);
>-    Base::getOwnNonIndexPropertyNames(thisObject, globalObject, propertyNameArray, enumerationMode);
>-}
>-
>-void ErrorInstance::getStructurePropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNameArray, EnumerationMode enumerationMode)
>-{
>-    VM& vm = globalObject->vm();
>-    ErrorInstance* thisObject = jsCast<ErrorInstance*>(object);
>-    thisObject->materializeErrorInfoIfNeeded(vm);
>-    Base::getStructurePropertyNames(thisObject, globalObject, propertyNameArray, enumerationMode);
>+    if (mode == DontEnumPropertiesMode::Include)
>+        thisObject->materializeErrorInfoIfNeeded(vm);
> }
> 
> bool ErrorInstance::defineOwnProperty(JSObject* object, JSGlobalObject* globalObject, PropertyName propertyName, const PropertyDescriptor& descriptor, bool shouldThrow)
>Index: Source/JavaScriptCore/runtime/ErrorInstance.h
>===================================================================
>--- Source/JavaScriptCore/runtime/ErrorInstance.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/ErrorInstance.h	(working copy)
>@@ -29,7 +29,7 @@ namespace JSC {
> class ErrorInstance : public JSNonFinalObject {
> public:
>     using Base = JSNonFinalObject;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnSpecialPropertyNames;
>     static constexpr bool needsDestruction = true;
> 
>     static void destroy(JSCell* cell)
>@@ -93,8 +93,7 @@ protected:
>     void finishCreation(VM&, JSGlobalObject*, const String&, SourceAppender = nullptr, RuntimeType = TypeNothing, bool useCurrentFrame = true);
> 
>     static bool getOwnPropertySlot(JSObject*, JSGlobalObject*, PropertyName, PropertySlot&);
>-    static void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    static void getStructurePropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     static bool defineOwnProperty(JSObject*, JSGlobalObject*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
>     static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
>     static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
>Index: Source/JavaScriptCore/runtime/GenericArguments.h
>===================================================================
>--- Source/JavaScriptCore/runtime/GenericArguments.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/GenericArguments.h	(working copy)
>@@ -36,7 +36,7 @@ template<typename Type>
> class GenericArguments : public JSNonFinalObject {
> public:
>     typedef JSNonFinalObject Base;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnPropertyNames | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero;
> 
> protected:
>     GenericArguments(VM& vm, Structure* structure)
>@@ -47,7 +47,7 @@ protected:
>     static void visitChildren(JSCell*, SlotVisitor&);
>     static bool getOwnPropertySlot(JSObject*, JSGlobalObject*, PropertyName, PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSObject*, JSGlobalObject*, unsigned propertyName, PropertySlot&);
>-    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
>     static bool putByIndex(JSCell*, JSGlobalObject*, unsigned propertyName, JSValue, bool shouldThrow);
>     static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
>Index: Source/JavaScriptCore/runtime/GenericArgumentsInlines.h
>===================================================================
>--- Source/JavaScriptCore/runtime/GenericArgumentsInlines.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/GenericArgumentsInlines.h	(working copy)
>@@ -90,7 +90,7 @@ bool GenericArguments<Type>::getOwnPrope
> }
> 
> template<typename Type>
>-void GenericArguments<Type>::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& array, EnumerationMode mode)
>+void GenericArguments<Type>::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& array, DontEnumPropertiesMode mode)
> {
>     VM& vm = globalObject->vm();
>     Type* thisObject = jsCast<Type*>(object);
>@@ -101,15 +101,15 @@ void GenericArguments<Type>::getOwnPrope
>                 continue;
>             array.add(Identifier::from(vm, i));
>         }
>+        thisObject->getOwnIndexedPropertyNames(globalObject, array, mode);
>     }
> 
>-    if (mode.includeDontEnumProperties() && !thisObject->overrodeThings()) {
>+    if (mode == DontEnumPropertiesMode::Include && !thisObject->overrodeThings()) {
>         array.add(vm.propertyNames->length);
>         array.add(vm.propertyNames->callee);
>-        if (array.includeSymbolProperties())
>-            array.add(vm.propertyNames->iteratorSymbol);
>+        array.add(vm.propertyNames->iteratorSymbol);
>     }
>-    Base::getOwnPropertyNames(thisObject, globalObject, array, mode);
>+    thisObject->getOwnNonIndexPropertyNames(globalObject, array, mode);
> }
> 
> template<typename Type>
>Index: Source/JavaScriptCore/runtime/JSArray.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSArray.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSArray.cpp	(working copy)
>@@ -283,15 +283,11 @@ static int compareKeysForQSort(const voi
>     return (da > db) - (da < db);
> }
> 
>-void JSArray::getOwnNonIndexPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSArray::getOwnSpecialPropertyNames(JSObject*, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = globalObject->vm();
>-    JSArray* thisObject = jsCast<JSArray*>(object);
>-
>-    if (mode.includeDontEnumProperties())
>+    if (mode == DontEnumPropertiesMode::Include)
>         propertyNames.add(vm.propertyNames->length);
>-
>-    JSObject::getOwnNonIndexPropertyNames(thisObject, globalObject, propertyNames, mode);
> }
> 
> // This method makes room in the vector, but leaves the new space for count slots uncleared.
>Index: Source/JavaScriptCore/runtime/JSArray.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSArray.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSArray.h	(working copy)
>@@ -40,7 +40,7 @@ class JSArray : public JSNonFinalObject 
> 
> public:
>     typedef JSNonFinalObject Base;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnSpecialPropertyNames;
> 
>     static size_t allocationSize(Checked<size_t> inlineCapacity)
>     {
>@@ -189,7 +189,7 @@ protected:
>     static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
> 
>     static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
>-    JS_EXPORT_PRIVATE static void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    JS_EXPORT_PRIVATE static void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
> 
> private:
>     bool isLengthWritable()
>Index: Source/JavaScriptCore/runtime/JSCell.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSCell.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSCell.cpp	(working copy)
>@@ -206,12 +206,12 @@ void JSCell::doPutPropertySecurityCheck(
>     RELEASE_ASSERT_NOT_REACHED();
> }
> 
>-void JSCell::getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode)
>+void JSCell::getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode)
> {
>     RELEASE_ASSERT_NOT_REACHED();
> }
> 
>-void JSCell::getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode)
>+void JSCell::getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode)
> {
>     RELEASE_ASSERT_NOT_REACHED();
> }
>@@ -233,11 +233,6 @@ const char* JSCell::className(VM& vm) co
>     return classInfo(vm)->className;
> }
> 
>-void JSCell::getPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode)
>-{
>-    RELEASE_ASSERT_NOT_REACHED();
>-}
>-
> bool JSCell::customHasInstance(JSObject*, JSGlobalObject*, JSValue)
> {
>     RELEASE_ASSERT_NOT_REACHED();
>@@ -256,16 +251,6 @@ uint32_t JSCell::getEnumerableLength(JSG
>     return 0;
> }
> 
>-void JSCell::getStructurePropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode)
>-{
>-    RELEASE_ASSERT_NOT_REACHED();
>-}
>-
>-void JSCell::getGenericPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode)
>-{
>-    RELEASE_ASSERT_NOT_REACHED();
>-}
>-
> bool JSCell::preventExtensions(JSObject*, JSGlobalObject*)
> {
>     RELEASE_ASSERT_NOT_REACHED();
>Index: Source/JavaScriptCore/runtime/JSCell.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSCell.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSCell.h	(working copy)
>@@ -244,13 +244,10 @@ protected:
> 
>     // Dummy implementations of override-able static functions for classes to put in their MethodTable
>     static JSValue defaultValue(const JSObject*, JSGlobalObject*, PreferredPrimitiveType);
>-    static NO_RETURN_DUE_TO_CRASH void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    static NO_RETURN_DUE_TO_CRASH void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    static NO_RETURN_DUE_TO_CRASH void getPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static NO_RETURN_DUE_TO_CRASH void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>+    static NO_RETURN_DUE_TO_CRASH void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
> 
>     static uint32_t getEnumerableLength(JSGlobalObject*, JSObject*);
>-    static NO_RETURN_DUE_TO_CRASH void getStructurePropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    static NO_RETURN_DUE_TO_CRASH void getGenericPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>     static NO_RETURN_DUE_TO_CRASH bool preventExtensions(JSObject*, JSGlobalObject*);
>     static NO_RETURN_DUE_TO_CRASH bool isExtensible(JSObject*, JSGlobalObject*);
>     static NO_RETURN_DUE_TO_CRASH bool setPrototype(JSObject*, JSGlobalObject*, JSValue, bool);
>Index: Source/JavaScriptCore/runtime/JSFunction.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSFunction.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSFunction.cpp	(working copy)
>@@ -494,13 +494,13 @@ bool JSFunction::getOwnPropertySlot(JSOb
>     RELEASE_AND_RETURN(scope, Base::getOwnPropertySlot(thisObject, globalObject, propertyName, slot));
> }
> 
>-void JSFunction::getOwnNonIndexPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSFunction::getOwnSpecialPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     JSFunction* thisObject = jsCast<JSFunction*>(object);
>     VM& vm = globalObject->vm();
>     auto scope = DECLARE_THROW_SCOPE(vm);
> 
>-    if (mode.includeDontEnumProperties()) {
>+    if (mode == DontEnumPropertiesMode::Include) {
>         if (!thisObject->isHostOrBuiltinFunction()) {
>             // Make sure prototype has been reified.
>             PropertySlot slot(thisObject, PropertySlot::InternalMethodType::VMInquiry, &vm);
>@@ -524,7 +524,6 @@ void JSFunction::getOwnNonIndexPropertyN
>             }
>         }
>     }
>-    RELEASE_AND_RETURN(scope, Base::getOwnNonIndexPropertyNames(thisObject, globalObject, propertyNames, mode));
> }
> 
> bool JSFunction::put(JSCell* cell, JSGlobalObject* globalObject, PropertyName propertyName, JSValue value, PutPropertySlot& slot)
>Index: Source/JavaScriptCore/runtime/JSFunction.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSFunction.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSFunction.h	(working copy)
>@@ -70,7 +70,7 @@ public:
>     }
>     
>     typedef JSCallee Base;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesAnyFormOfGetPropertyNames | OverridesGetCallData;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnSpecialPropertyNames | OverridesGetCallData;
> 
>     static size_t allocationSize(Checked<size_t> inlineCapacity)
>     {
>@@ -173,7 +173,7 @@ protected:
>     void finishCreation(VM&);
> 
>     static bool getOwnPropertySlot(JSObject*, JSGlobalObject*, PropertyName, PropertySlot&);
>-    static void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode = EnumerationMode());
>+    static void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     static bool defineOwnProperty(JSObject*, JSGlobalObject*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
> 
>     static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
>Index: Source/JavaScriptCore/runtime/JSGenericTypedArrayView.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSGenericTypedArrayView.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSGenericTypedArrayView.h	(working copy)
>@@ -96,7 +96,7 @@ public:
>     using Base = JSArrayBufferView;
>     typedef typename Adaptor::Type ElementType;
> 
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesAnyFormOfGetPropertyNames | OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnPropertyNames | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero;
> 
>     static constexpr unsigned elementSize = sizeof(typename Adaptor::Type);
> 
>@@ -304,7 +304,7 @@ private:
>     static bool putByIndex(JSCell*, JSGlobalObject*, unsigned propertyName, JSValue, bool shouldThrow);
>     static bool deletePropertyByIndex(JSCell*, JSGlobalObject*, unsigned propertyName);
>     
>-    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
> 
>     static size_t estimatedSize(JSCell*, VM&);
>     static void visitChildren(JSCell*, SlotVisitor&);
>Index: Source/JavaScriptCore/runtime/JSGenericTypedArrayViewInlines.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSGenericTypedArrayViewInlines.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSGenericTypedArrayViewInlines.h	(working copy)
>@@ -464,7 +464,7 @@ bool JSGenericTypedArrayView<Adaptor>::d
> 
> template<typename Adaptor>
> void JSGenericTypedArrayView<Adaptor>::getOwnPropertyNames(
>-    JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& array, EnumerationMode mode)
>+    JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& array, DontEnumPropertiesMode mode)
> {
>     VM& vm = globalObject->vm();
>     JSGenericTypedArrayView* thisObject = jsCast<JSGenericTypedArrayView*>(object);
>@@ -474,7 +474,7 @@ void JSGenericTypedArrayView<Adaptor>::g
>             array.add(Identifier::from(vm, i));
>     }
>     
>-    return Base::getOwnPropertyNames(object, globalObject, array, mode);
>+    thisObject->getOwnNonIndexPropertyNames(globalObject, array, mode);
> }
> 
> template<typename Adaptor>
>Index: Source/JavaScriptCore/runtime/JSGlobalObject.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSGlobalObject.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSGlobalObject.h	(working copy)
>@@ -571,9 +571,7 @@ public:
>         
> public:
>     using Base = JSSegmentedVariableObject;
>-    // Do we realy need OverridesAnyFormOfGetPropertyNames here?
>-    // FIXME: https://bugs.webkit.org/show_bug.cgi?id=212954
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | HasStaticPropertyTable | OverridesGetOwnPropertySlot | OverridesAnyFormOfGetPropertyNames | IsImmutablePrototypeExoticObject;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | HasStaticPropertyTable | OverridesGetOwnPropertySlot | IsImmutablePrototypeExoticObject;
> 
>     static constexpr bool needsDestruction = true;
>     template<typename CellType, SubspaceAccess mode>
>Index: Source/JavaScriptCore/runtime/JSLexicalEnvironment.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSLexicalEnvironment.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSLexicalEnvironment.cpp	(working copy)
>@@ -64,7 +64,7 @@ void JSLexicalEnvironment::analyzeHeap(J
>     }
> }
> 
>-void JSLexicalEnvironment::getOwnNonIndexPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSLexicalEnvironment::getOwnSpecialPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     JSLexicalEnvironment* thisObject = jsCast<JSLexicalEnvironment*>(object);
> 
>@@ -73,7 +73,7 @@ void JSLexicalEnvironment::getOwnNonInde
>         SymbolTable::Map::iterator end = thisObject->symbolTable()->end(locker);
>         VM& vm = globalObject->vm();
>         for (SymbolTable::Map::iterator it = thisObject->symbolTable()->begin(locker); it != end; ++it) {
>-            if (it->value.getAttributes() & PropertyAttribute::DontEnum && !mode.includeDontEnumProperties())
>+            if (mode == DontEnumPropertiesMode::Exclude && it->value.isDontEnum())
>                 continue;
>             if (!thisObject->isValidScopeOffset(it->value.scopeOffset()))
>                 continue;
>@@ -82,8 +82,6 @@ void JSLexicalEnvironment::getOwnNonInde
>             propertyNames.add(Identifier::fromUid(vm, it->key.get()));
>         }
>     }
>-    // Skip the JSSymbolTableObject's implementation of getOwnNonIndexPropertyNames
>-    JSObject::getOwnNonIndexPropertyNames(thisObject, globalObject, propertyNames, mode);
> }
> 
> bool JSLexicalEnvironment::getOwnPropertySlot(JSObject* object, JSGlobalObject* globalObject, PropertyName propertyName, PropertySlot& slot)
>Index: Source/JavaScriptCore/runtime/JSLexicalEnvironment.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSLexicalEnvironment.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSLexicalEnvironment.h	(working copy)
>@@ -48,7 +48,7 @@ public:
>     }
> 
>     using Base = JSSymbolTableObject;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnSpecialPropertyNames;
> 
>     WriteBarrierBase<Unknown>* variables()
>     {
>@@ -106,7 +106,7 @@ public:
>     }
>         
>     static bool getOwnPropertySlot(JSObject*, JSGlobalObject*, PropertyName, PropertySlot&);
>-    static void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
> 
>     static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
> 
>Index: Source/JavaScriptCore/runtime/JSModuleEnvironment.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSModuleEnvironment.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSModuleEnvironment.cpp	(working copy)
>@@ -96,7 +96,7 @@ bool JSModuleEnvironment::getOwnProperty
>     return Base::getOwnPropertySlot(thisObject, globalObject, propertyName, slot);
> }
> 
>-void JSModuleEnvironment::getOwnNonIndexPropertyNames(JSObject* cell, JSGlobalObject* globalObject, PropertyNameArray& propertyNamesArray, EnumerationMode mode)
>+void JSModuleEnvironment::getOwnSpecialPropertyNames(JSObject* cell, JSGlobalObject*, PropertyNameArray& propertyNamesArray, DontEnumPropertiesMode)
> {
>     JSModuleEnvironment* thisObject = jsCast<JSModuleEnvironment*>(cell);
>     if (propertyNamesArray.includeStringProperties()) {
>@@ -106,7 +106,6 @@ void JSModuleEnvironment::getOwnNonIndex
>                 propertyNamesArray.add(importEntry.localName);
>         }
>     }
>-    return Base::getOwnNonIndexPropertyNames(thisObject, globalObject, propertyNamesArray, mode);
> }
> 
> bool JSModuleEnvironment::put(JSCell* cell, JSGlobalObject* globalObject, PropertyName propertyName, JSValue value, PutPropertySlot& slot)
>Index: Source/JavaScriptCore/runtime/JSModuleEnvironment.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSModuleEnvironment.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSModuleEnvironment.h	(working copy)
>@@ -40,7 +40,7 @@ class JSModuleEnvironment final : public
>     friend class LLIntOffsetsExtractor;
> public:
>     using Base = JSLexicalEnvironment;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnSpecialPropertyNames;
> 
>     static JSModuleEnvironment* create(VM& vm, JSGlobalObject* globalObject, JSScope* currentScope, SymbolTable* symbolTable, JSValue initialValue, AbstractModuleRecord* moduleRecord)
>     {
>@@ -73,7 +73,7 @@ public:
>     }
> 
>     static bool getOwnPropertySlot(JSObject*, JSGlobalObject*, PropertyName, PropertySlot&);
>-    static void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
>     static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
> 
>Index: Source/JavaScriptCore/runtime/JSModuleNamespaceObject.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSModuleNamespaceObject.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSModuleNamespaceObject.cpp	(working copy)
>@@ -217,7 +217,7 @@ bool JSModuleNamespaceObject::deleteProp
>     return !thisObject->m_exports.contains(propertyName.uid());
> }
> 
>-void JSModuleNamespaceObject::getOwnPropertyNames(JSObject* cell, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSModuleNamespaceObject::getOwnPropertyNames(JSObject* cell, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = globalObject->vm();
>     auto scope = DECLARE_THROW_SCOPE(vm);
>@@ -225,7 +225,7 @@ void JSModuleNamespaceObject::getOwnProp
>     // https://tc39.es/ecma262/#sec-module-namespace-exotic-objects-ownpropertykeys
>     JSModuleNamespaceObject* thisObject = jsCast<JSModuleNamespaceObject*>(cell);
>     for (const auto& name : thisObject->m_names) {
>-        if (!mode.includeDontEnumProperties()) {
>+        if (mode == DontEnumPropertiesMode::Exclude) {
>             // Perform [[GetOwnProperty]] to throw ReferenceError if binding is uninitialized.
>             PropertySlot slot(cell, PropertySlot::InternalMethodType::GetOwnProperty);
>             thisObject->getOwnPropertySlotCommon(globalObject, name.impl(), slot);
>@@ -233,7 +233,8 @@ void JSModuleNamespaceObject::getOwnProp
>         }
>         propertyNames.add(name.impl());
>     }
>-    Base::getOwnPropertyNames(thisObject, globalObject, propertyNames, mode);
>+    if (propertyNames.includeSymbolProperties())
>+        thisObject->getOwnNonIndexPropertyNames(globalObject, propertyNames, mode);
> }
> 
> bool JSModuleNamespaceObject::defineOwnProperty(JSObject* cell, JSGlobalObject* globalObject, PropertyName propertyName, const PropertyDescriptor& descriptor, bool shouldThrow)
>Index: Source/JavaScriptCore/runtime/JSModuleNamespaceObject.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSModuleNamespaceObject.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSModuleNamespaceObject.h	(working copy)
>@@ -33,7 +33,7 @@ namespace JSC {
> class JSModuleNamespaceObject final : public JSNonFinalObject {
> public:
>     using Base = JSNonFinalObject;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | OverridesAnyFormOfGetPropertyNames | GetOwnPropertySlotIsImpureForPropertyAbsence | IsImmutablePrototypeExoticObject;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnPropertyNames | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | GetOwnPropertySlotIsImpureForPropertyAbsence | IsImmutablePrototypeExoticObject;
> 
>     static constexpr bool needsDestruction = true;
>     static void destroy(JSCell*);
>@@ -57,7 +57,7 @@ public:
>     JS_EXPORT_PRIVATE static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
>     JS_EXPORT_PRIVATE static bool putByIndex(JSCell*, JSGlobalObject*, unsigned propertyName, JSValue, bool shouldThrow);
>     JS_EXPORT_PRIVATE static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
>-    JS_EXPORT_PRIVATE static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    JS_EXPORT_PRIVATE static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     JS_EXPORT_PRIVATE static bool defineOwnProperty(JSObject*, JSGlobalObject*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
> 
>     DECLARE_EXPORT_INFO;
>Index: Source/JavaScriptCore/runtime/JSONObject.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSONObject.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSONObject.cpp	(working copy)
>@@ -500,7 +500,7 @@ bool Stringifier::Holder::appendNextProp
>                 m_propertyNames = stringifier.m_arrayReplacerPropertyNames.data();
>             else {
>                 PropertyNameArray objectPropertyNames(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
>-                m_object->methodTable(vm)->getOwnPropertyNames(m_object, globalObject, objectPropertyNames, EnumerationMode());
>+                m_object->methodTable(vm)->getOwnPropertyNames(m_object, globalObject, objectPropertyNames, DontEnumPropertiesMode::Exclude);
>                 RETURN_IF_EXCEPTION(scope, false);
>                 m_propertyNames = objectPropertyNames.releaseData();
>             }
>@@ -719,7 +719,7 @@ NEVER_INLINE JSValue Walker::walk(JSValu
>                 markedStack.appendWithCrashOnOverflow(object);
>                 indexStack.append(0);
>                 propertyStack.append(PropertyNameArray(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude));
>-                object->methodTable(vm)->getOwnPropertyNames(object, m_globalObject, propertyStack.last(), EnumerationMode());
>+                object->methodTable(vm)->getOwnPropertyNames(object, m_globalObject, propertyStack.last(), DontEnumPropertiesMode::Exclude);
>                 RETURN_IF_EXCEPTION(scope, { });
>             }
>             objectStartVisitMember:
>Index: Source/JavaScriptCore/runtime/JSObject.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSObject.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSObject.cpp	(working copy)
>@@ -72,18 +72,19 @@ const ClassInfo JSObject::s_info = { "Ob
> 
> const ClassInfo JSFinalObject::s_info = { "Object", &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSFinalObject) };
> 
>-static inline void getClassPropertyNames(JSGlobalObject* globalObject, const ClassInfo* classInfo, PropertyNameArray& propertyNames, EnumerationMode mode)
>+ALWAYS_INLINE void JSObject::getNonReifiedStaticPropertyNames(VM& vm, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>-    VM& vm = globalObject->vm();
>+    if (staticPropertiesReified(vm))
>+        return;
> 
>     // Add properties from the static hashtables of properties
>-    for (; classInfo; classInfo = classInfo->parentClass) {
>-        const HashTable* table = classInfo->staticPropHashTable;
>+    for (const ClassInfo* info = classInfo(vm); info; info = info->parentClass) {
>+        const HashTable* table = info->staticPropHashTable;
>         if (!table)
>             continue;
> 
>         for (auto iter = table->begin(); iter != table->end(); ++iter) {
>-            if (!(iter->attributes() & PropertyAttribute::DontEnum) || mode.includeDontEnumProperties())
>+            if (mode == DontEnumPropertiesMode::Include || !(iter->attributes() & PropertyAttribute::DontEnum))
>                 propertyNames.add(Identifier::fromString(vm, iter.key()));
>         }
>     }
>@@ -2380,54 +2381,50 @@ JSC_DEFINE_HOST_FUNCTION(objectPrivateFu
>     return JSValue::encode(jsBoolean(JSObject::defaultHasInstance(globalObject, value, proto)));
> }
> 
>-// FIXME: Assert that properties returned by getOwnPropertyNames() are reported enumerable by getOwnPropertySlot().
>-// https://bugs.webkit.org/show_bug.cgi?id=219926
>-void JSObject::getPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+constexpr unsigned maximumPrototypeChainDepth = 40000;
>+void JSObject::getPropertyNames(JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = globalObject->vm();
>     auto scope = DECLARE_THROW_SCOPE(vm);
> 
>-    if (UNLIKELY(!vm.isSafeToRecurseSoft())) {
>-        throwStackOverflowError(globalObject, scope);
>-        return;
>-    }
>+    JSObject* object = this;
>+    unsigned prototypeCount = 0;
> 
>-    object->methodTable(vm)->getOwnPropertyNames(object, globalObject, propertyNames, mode);
>-    RETURN_IF_EXCEPTION(scope, void());
>+    while (true) {
>+        object->methodTable(vm)->getOwnPropertyNames(object, globalObject, propertyNames, mode);
>+        RETURN_IF_EXCEPTION(scope, void());
> 
>-    JSValue nextProto = object->getPrototype(vm, globalObject);
>-    RETURN_IF_EXCEPTION(scope, void());
>-    if (nextProto.isNull())
>-        return;
>+        JSValue prototype = object->getPrototype(vm, globalObject);
>+        RETURN_IF_EXCEPTION(scope, void());
>+        if (prototype.isNull())
>+            break;
> 
>-    JSObject* prototype = asObject(nextProto);
>-    while(1) {
>-        if (prototype->structure(vm)->typeInfo().overridesGetPropertyNames()) {
>-            scope.release();
>-            prototype->methodTable(vm)->getPropertyNames(prototype, globalObject, propertyNames, mode);
>+        if (UNLIKELY(++prototypeCount > maximumPrototypeChainDepth)) {
>+            throwStackOverflowError(globalObject, scope);
>             return;
>         }
>-        prototype->methodTable(vm)->getOwnPropertyNames(prototype, globalObject, propertyNames, mode);
>-        RETURN_IF_EXCEPTION(scope, void());
>-        nextProto = prototype->getPrototype(vm, globalObject);
>-        RETURN_IF_EXCEPTION(scope, void());
>-        if (nextProto.isNull())
>-            break;
>-        prototype = asObject(nextProto);
>+
>+        object = asObject(prototype);
>     }
> }
> 
>-void JSObject::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSObject::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>-    VM& vm = globalObject->vm();
>-    if (!mode.includeJSObjectProperties()) {
>-        // We still have to get non-indexed properties from any subclasses of JSObject that have them.
>-        object->methodTable(vm)->getOwnNonIndexPropertyNames(object, globalObject, propertyNames, mode);
>-        return;
>-    }
>+    object->getOwnIndexedPropertyNames(globalObject, propertyNames, mode);
>+    object->getOwnNonIndexPropertyNames(globalObject, propertyNames, mode);
>+}
>+
>+void JSObject::getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode)
>+{
>+    // Structure::validateFlags() breaks if this method isn't exported, which is impossible if it's inlined.
>+}
>+
>+void JSObject::getOwnIndexedPropertyNames(JSGlobalObject*, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
>+{
>+    JSObject* object = this;
> 
>     if (propertyNames.includeStringProperties()) {
>-        // Add numeric properties first. That appears to be the accepted convention.
>+        // Add numeric properties first per step 2 of https://tc39.es/ecma262/#sec-ordinaryownpropertykeys
>         // FIXME: Filling PropertyNameArray with an identifier for every integer
>         // is incredibly inefficient for large arrays. We need a different approach,
>         // which almost certainly means a different structure for PropertyNameArray.
>@@ -2475,7 +2472,7 @@ void JSObject::getOwnPropertyNames(JSObj
>                 
>                 SparseArrayValueMap::const_iterator end = map->end();
>                 for (SparseArrayValueMap::const_iterator it = map->begin(); it != end; ++it) {
>-                    if (mode.includeDontEnumProperties() || !(it->value.attributes() & PropertyAttribute::DontEnum))
>+                    if (mode == DontEnumPropertiesMode::Include || !(it->value.attributes() & PropertyAttribute::DontEnum))
>                         keys.uncheckedAppend(static_cast<unsigned>(it->key));
>                 }
>                 
>@@ -2490,20 +2487,19 @@ void JSObject::getOwnPropertyNames(JSObj
>             RELEASE_ASSERT_NOT_REACHED();
>         }
>     }
>-
>-    object->methodTable(vm)->getOwnNonIndexPropertyNames(object, globalObject, propertyNames, mode);
> }
> 
>-void JSObject::getOwnNonIndexPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSObject::getOwnNonIndexPropertyNames(JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = globalObject->vm();
>-    if (!object->staticPropertiesReified(vm))
>-        getClassPropertyNames(globalObject, object->classInfo(vm), propertyNames, mode);
>+    auto scope = DECLARE_THROW_SCOPE(vm);
> 
>-    if (!mode.includeJSObjectProperties())
>-        return;
>-    
>-    object->structure(vm)->getPropertyNamesFromStructure(vm, propertyNames, mode);
>+    methodTable(vm)->getOwnSpecialPropertyNames(this, globalObject, propertyNames, mode);
>+    RETURN_IF_EXCEPTION(scope, void());
>+
>+    getNonReifiedStaticPropertyNames(vm, propertyNames, mode);
>+    structure(vm)->getPropertyNamesFromStructure(vm, propertyNames, mode);
>+    scope.assertNoException();
> }
> 
> double JSObject::toNumber(JSGlobalObject* globalObject) const
>@@ -3837,41 +3833,6 @@ uint32_t JSObject::getEnumerableLength(J
>     }
> }
> 
>-void JSObject::getStructurePropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>-{
>-    VM& vm = globalObject->vm();
>-    object->structure(vm)->getPropertyNamesFromStructure(vm, propertyNames, mode);
>-}
>-
>-void JSObject::getGenericPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>-{
>-    VM& vm = globalObject->vm();
>-    auto scope = DECLARE_THROW_SCOPE(vm);
>-    object->methodTable(vm)->getOwnPropertyNames(object, globalObject, propertyNames, EnumerationMode(mode, JSObjectPropertiesMode::Exclude));
>-    RETURN_IF_EXCEPTION(scope, void());
>-
>-    JSValue nextProto = object->getPrototype(vm, globalObject);
>-    RETURN_IF_EXCEPTION(scope, void());
>-    if (nextProto.isNull())
>-        return;
>-
>-    JSObject* prototype = asObject(nextProto);
>-    while (true) {
>-        if (prototype->structure(vm)->typeInfo().overridesGetPropertyNames()) {
>-            scope.release();
>-            prototype->methodTable(vm)->getPropertyNames(prototype, globalObject, propertyNames, mode);
>-            return;
>-        }
>-        prototype->methodTable(vm)->getOwnPropertyNames(prototype, globalObject, propertyNames, mode);
>-        RETURN_IF_EXCEPTION(scope, void());
>-        nextProto = prototype->getPrototype(vm, globalObject);
>-        RETURN_IF_EXCEPTION(scope, void());
>-        if (nextProto.isNull())
>-            break;
>-        prototype = asObject(nextProto);
>-    }
>-}
>-
> // Implements GetMethod(O, P) in section 7.3.9 of the spec.
> // http://www.ecma-international.org/ecma-262/6.0/index.html#sec-getmethod
> JSValue JSObject::getMethod(JSGlobalObject* globalObject, CallData& callData, const Identifier& ident, const String& errorMessage)
>Index: Source/JavaScriptCore/runtime/JSObject.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSObject.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSObject.h	(working copy)
>@@ -674,13 +674,14 @@ public:
>     JS_EXPORT_PRIVATE bool hasInstance(JSGlobalObject*, JSValue);
>     static bool defaultHasInstance(JSGlobalObject*, JSValue, JSValue prototypeProperty);
> 
>-    JS_EXPORT_PRIVATE static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    JS_EXPORT_PRIVATE static void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    JS_EXPORT_PRIVATE static void getPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    JS_EXPORT_PRIVATE void getPropertyNames(JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>+    JS_EXPORT_PRIVATE static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>+    JS_EXPORT_PRIVATE static void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>+    JS_EXPORT_PRIVATE void getOwnIndexedPropertyNames(JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>+    JS_EXPORT_PRIVATE void getOwnNonIndexPropertyNames(JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>+    void getNonReifiedStaticPropertyNames(VM&, PropertyNameArray&, DontEnumPropertiesMode);
> 
>     JS_EXPORT_PRIVATE static uint32_t getEnumerableLength(JSGlobalObject*, JSObject*);
>-    JS_EXPORT_PRIVATE static void getStructurePropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    JS_EXPORT_PRIVATE static void getGenericPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
> 
>     JS_EXPORT_PRIVATE JSValue toPrimitive(JSGlobalObject*, PreferredPrimitiveType = NoPreference) const;
>     JS_EXPORT_PRIVATE double toNumber(JSGlobalObject*) const;
>Index: Source/JavaScriptCore/runtime/JSPropertyNameEnumerator.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSPropertyNameEnumerator.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSPropertyNameEnumerator.cpp	(working copy)
>@@ -87,4 +87,52 @@ void JSPropertyNameEnumerator::visitChil
>     }
> }
> 
>+// FIXME: Assert that properties returned by getOwnPropertyNames() are reported enumerable by getOwnPropertySlot().
>+// https://bugs.webkit.org/show_bug.cgi?id=219926
>+void getEnumerablePropertyNames(JSGlobalObject* globalObject, JSObject* base, PropertyNameArray& propertyNames, uint32_t& indexedLength, uint32_t& structurePropertyCount)
>+{
>+    VM& vm = globalObject->vm();
>+    auto scope = DECLARE_THROW_SCOPE(vm);
>+
>+    Structure* structure = base->structure(vm);
>+    if (structure->canAccessPropertiesQuicklyForEnumeration() && indexedLength == base->getArrayLength()) {
>+        // Inlined JSObject::getOwnNonIndexPropertyNames()
>+        base->methodTable(vm)->getOwnSpecialPropertyNames(base, globalObject, propertyNames, DontEnumPropertiesMode::Exclude);
>+        RETURN_IF_EXCEPTION(scope, void());
>+
>+        base->getNonReifiedStaticPropertyNames(vm, propertyNames, DontEnumPropertiesMode::Exclude);
>+        unsigned nonStructurePropertyCount = propertyNames.size();
>+        structure->getPropertyNamesFromStructure(vm, propertyNames, DontEnumPropertiesMode::Exclude);
>+        scope.assertNoException();
>+
>+        // |propertyNames| contains properties exclusively from the structure.
>+        if (!nonStructurePropertyCount)
>+            structurePropertyCount = propertyNames.size();
>+    } else {
>+        base->methodTable(vm)->getOwnPropertyNames(base, globalObject, propertyNames, DontEnumPropertiesMode::Exclude);
>+        RETURN_IF_EXCEPTION(scope, void());
>+        // |propertyNames| contains all indexed properties, so disable enumeration based on getEnumerableLength().
>+        indexedLength = 0;
>+    }
>+
>+    JSObject* object = base;
>+    unsigned prototypeCount = 0;
>+
>+    while (true) {
>+        JSValue prototype = object->getPrototype(vm, globalObject);
>+        RETURN_IF_EXCEPTION(scope, void());
>+        if (prototype.isNull())
>+            break;
>+
>+        if (UNLIKELY(++prototypeCount > maximumPrototypeChainDepth)) {
>+            throwStackOverflowError(globalObject, scope);
>+            return;
>+        }
>+
>+        object = asObject(prototype);
>+        object->methodTable(vm)->getOwnPropertyNames(object, globalObject, propertyNames, DontEnumPropertiesMode::Exclude);
>+        RETURN_IF_EXCEPTION(scope, void());
>+    }
>+}
>+
> } // namespace JSC
>Index: Source/JavaScriptCore/runtime/JSPropertyNameEnumerator.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSPropertyNameEnumerator.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSPropertyNameEnumerator.h	(working copy)
>@@ -101,6 +101,8 @@ private:
>     uint32_t m_cachedInlineCapacity;
> };
> 
>+void getEnumerablePropertyNames(JSGlobalObject*, JSObject*, PropertyNameArray&, uint32_t& indexedLength, uint32_t& structurePropertyCount);
>+
> inline JSPropertyNameEnumerator* propertyNameEnumerator(JSGlobalObject* globalObject, JSObject* base)
> {
>     VM& vm = getVM(globalObject);
>@@ -117,22 +119,8 @@ inline JSPropertyNameEnumerator* propert
>         return enumerator;
> 
>     uint32_t numberStructureProperties = 0;
>-
>     PropertyNameArray propertyNames(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
>-
>-    if (structure->canAccessPropertiesQuicklyForEnumeration() && indexedLength == base->getArrayLength()) {
>-        base->methodTable(vm)->getStructurePropertyNames(base, globalObject, propertyNames, EnumerationMode());
>-        scope.assertNoException();
>-
>-        numberStructureProperties = propertyNames.size();
>-
>-        base->methodTable(vm)->getGenericPropertyNames(base, globalObject, propertyNames, EnumerationMode());
>-    } else {
>-        // Generic property names vector contains all indexed property names.
>-        // So disable indexed property enumeration phase by setting |indexedLength| to 0.
>-        indexedLength = 0;
>-        base->methodTable(vm)->getPropertyNames(base, globalObject, propertyNames, EnumerationMode());
>-    }
>+    getEnumerablePropertyNames(globalObject, base, propertyNames, indexedLength, numberStructureProperties);
>     RETURN_IF_EXCEPTION(scope, nullptr);
> 
>     ASSERT(propertyNames.size() < UINT32_MAX);
>Index: Source/JavaScriptCore/runtime/JSProxy.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSProxy.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSProxy.cpp	(working copy)
>@@ -115,32 +115,13 @@ bool JSProxy::deletePropertyByIndex(JSCe
>     return thisObject->target()->methodTable(globalObject->vm())->deletePropertyByIndex(thisObject->target(), globalObject, propertyName);
> }
> 
>-void JSProxy::getPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>-{
>-    JSProxy* thisObject = jsCast<JSProxy*>(object);
>-    thisObject->target()->methodTable(globalObject->vm())->getPropertyNames(thisObject->target(), globalObject, propertyNames, mode);
>-}
>-
> uint32_t JSProxy::getEnumerableLength(JSGlobalObject* globalObject, JSObject* object)
> {
>     JSProxy* thisObject = jsCast<JSProxy*>(object);
>     return thisObject->target()->methodTable(globalObject->vm())->getEnumerableLength(globalObject, thisObject->target());
> }
> 
>-void JSProxy::getStructurePropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode)
>-{
>-    // Skip the structure loop, since it is invalid for proxies.
>-}
>-
>-void JSProxy::getGenericPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>-{
>-    JSProxy* thisObject = jsCast<JSProxy*>(object);
>-    // Get *all* of the property names, not just the generic ones, since we skipped the structure
>-    // ones above.
>-    thisObject->target()->methodTable(globalObject->vm())->getPropertyNames(thisObject->target(), globalObject, propertyNames, mode);
>-}
>-
>-void JSProxy::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSProxy::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     JSProxy* thisObject = jsCast<JSProxy*>(object);
>     thisObject->target()->methodTable(globalObject->vm())->getOwnPropertyNames(thisObject->target(), globalObject, propertyNames, mode);
>Index: Source/JavaScriptCore/runtime/JSProxy.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSProxy.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSProxy.h	(working copy)
>@@ -32,7 +32,7 @@ namespace JSC {
> class JSProxy : public JSNonFinalObject {
> public:
>     using Base = JSNonFinalObject;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetPropertyNames | OverridesAnyFormOfGetPropertyNames | OverridesGetPrototype | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnPropertyNames | OverridesGetPrototype | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero;
> 
>     template<typename CellType, SubspaceAccess>
>     static IsoSubspace* subspaceFor(VM& vm)
>@@ -95,11 +95,8 @@ protected:
>     JS_EXPORT_PRIVATE static bool putByIndex(JSCell*, JSGlobalObject*, unsigned, JSValue, bool shouldThrow);
>     JS_EXPORT_PRIVATE static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
>     JS_EXPORT_PRIVATE static bool deletePropertyByIndex(JSCell*, JSGlobalObject*, unsigned);
>-    JS_EXPORT_PRIVATE static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    JS_EXPORT_PRIVATE static void getPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    JS_EXPORT_PRIVATE static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     JS_EXPORT_PRIVATE static uint32_t getEnumerableLength(JSGlobalObject*, JSObject*);
>-    JS_EXPORT_PRIVATE static void getStructurePropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    JS_EXPORT_PRIVATE static void getGenericPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>     JS_EXPORT_PRIVATE static bool defineOwnProperty(JSObject*, JSGlobalObject*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
>     JS_EXPORT_PRIVATE static bool setPrototype(JSObject*, JSGlobalObject*, JSValue, bool shouldThrowIfCantSet);
>     JS_EXPORT_PRIVATE static JSValue getPrototype(JSObject*, JSGlobalObject*);
>Index: Source/JavaScriptCore/runtime/JSSymbolTableObject.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/JSSymbolTableObject.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSSymbolTableObject.cpp	(working copy)
>@@ -53,7 +53,7 @@ bool JSSymbolTableObject::deleteProperty
>     return Base::deleteProperty(thisObject, globalObject, propertyName, slot);
> }
> 
>-void JSSymbolTableObject::getOwnNonIndexPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSSymbolTableObject::getOwnSpecialPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = globalObject->vm();
>     JSSymbolTableObject* thisObject = jsCast<JSSymbolTableObject*>(object);
>@@ -61,15 +61,13 @@ void JSSymbolTableObject::getOwnNonIndex
>         ConcurrentJSLocker locker(thisObject->symbolTable()->m_lock);
>         SymbolTable::Map::iterator end = thisObject->symbolTable()->end(locker);
>         for (SymbolTable::Map::iterator it = thisObject->symbolTable()->begin(locker); it != end; ++it) {
>-            if (!(it->value.getAttributes() & PropertyAttribute::DontEnum) || mode.includeDontEnumProperties()) {
>+            if (mode == DontEnumPropertiesMode::Include || !it->value.isDontEnum()) {
>                 if (it->key->isSymbol() && !propertyNames.includeSymbolProperties())
>                     continue;
>                 propertyNames.add(Identifier::fromUid(vm, it->key.get()));
>             }
>         }
>     }
>-
>-    Base::getOwnNonIndexPropertyNames(thisObject, globalObject, propertyNames, mode);
> }
> 
> } // namespace JSC
>Index: Source/JavaScriptCore/runtime/JSSymbolTableObject.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSSymbolTableObject.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSSymbolTableObject.h	(working copy)
>@@ -39,12 +39,12 @@ namespace JSC {
> class JSSymbolTableObject : public JSScope {
> public:
>     using Base = JSScope;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnSpecialPropertyNames;
> 
>     SymbolTable* symbolTable() const { return m_symbolTable.get(); }
>     
>     JS_EXPORT_PRIVATE static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
>-    JS_EXPORT_PRIVATE static void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    JS_EXPORT_PRIVATE static void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     
>     static ptrdiff_t offsetOfSymbolTable() { return OBJECT_OFFSETOF(JSSymbolTableObject, m_symbolTable); }
> 
>Index: Source/JavaScriptCore/runtime/JSTypeInfo.h
>===================================================================
>--- Source/JavaScriptCore/runtime/JSTypeInfo.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/JSTypeInfo.h	(working copy)
>@@ -48,13 +48,8 @@ static constexpr unsigned TypeInfoPerCel
> // Out of line flags.
> 
> static constexpr unsigned ImplementsHasInstance = 1 << 8;
>-static constexpr unsigned OverridesGetPropertyNames = 1 << 9;
>-// OverridesAnyFormOfGetPropertyNames means that we cannot make assumptions about
>-// the cacheability or enumerability of property names, and therefore, we'll need
>-// to disable certain optimizations. This flag should be set if one or more of the
>-// following Object methods are overridden:
>-//     getOwnPropertyNames, getOwnNonIndexPropertyNames, getPropertyNames
>-static constexpr unsigned OverridesAnyFormOfGetPropertyNames = 1 << 10;
>+static constexpr unsigned OverridesGetOwnPropertyNames = 1 << 9;
>+static constexpr unsigned OverridesGetOwnSpecialPropertyNames = 1 << 10;
> static constexpr unsigned ProhibitsPropertyCaching = 1 << 11;
> static constexpr unsigned GetOwnPropertySlotIsImpure = 1 << 12;
> static constexpr unsigned NewImpurePropertyFiresWatchpoints = 1 << 13;
>@@ -103,8 +98,9 @@ public:
>     static bool perCellBit(InlineTypeFlags flags) { return flags & TypeInfoPerCellBit; }
>     bool overridesToThis() const { return isSetOnFlags1<OverridesToThis>(); }
>     bool structureIsImmortal() const { return isSetOnFlags2<StructureIsImmortal>(); }
>-    bool overridesGetPropertyNames() const { return isSetOnFlags2<OverridesGetPropertyNames>(); }
>-    bool overridesAnyFormOfGetPropertyNames() const { return isSetOnFlags2<OverridesAnyFormOfGetPropertyNames>(); }
>+    bool overridesGetOwnPropertyNames() const { return isSetOnFlags2<OverridesGetOwnPropertyNames>(); }
>+    bool overridesGetOwnSpecialPropertyNames() const { return isSetOnFlags2<OverridesGetOwnSpecialPropertyNames>(); }
>+    bool overridesAnyFormOfGetOwnPropertyNames() const { return overridesGetOwnPropertyNames() || overridesGetOwnSpecialPropertyNames(); }
>     bool overridesGetPrototype() const { return isSetOnFlags2<OverridesGetPrototype>(); }
>     bool prohibitsPropertyCaching() const { return isSetOnFlags2<ProhibitsPropertyCaching>(); }
>     bool getOwnPropertySlotIsImpure() const { return isSetOnFlags2<GetOwnPropertySlotIsImpure>(); }
>Index: Source/JavaScriptCore/runtime/ObjectConstructor.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/ObjectConstructor.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/ObjectConstructor.cpp	(working copy)
>@@ -186,7 +186,7 @@ JSValue objectConstructorGetOwnPropertyD
>     VM& vm = globalObject->vm();
>     auto scope = DECLARE_THROW_SCOPE(vm);
>     PropertyNameArray properties(vm, PropertyNameMode::StringsAndSymbols, PrivateSymbolMode::Exclude);
>-    object->methodTable(vm)->getOwnPropertyNames(object, globalObject, properties, EnumerationMode(DontEnumPropertiesMode::Include));
>+    object->methodTable(vm)->getOwnPropertyNames(object, globalObject, properties, DontEnumPropertiesMode::Include);
>     RETURN_IF_EXCEPTION(scope, { });
> 
>     JSObject* descriptors = constructEmptyObject(globalObject);
>@@ -294,7 +294,7 @@ JSC_DEFINE_HOST_FUNCTION(objectConstruct
>             auto canPerformFastPropertyEnumerationForObjectAssign = [] (Structure* structure) {
>                 if (structure->typeInfo().overridesGetOwnPropertySlot())
>                     return false;
>-                if (structure->typeInfo().overridesAnyFormOfGetPropertyNames())
>+                if (structure->typeInfo().overridesAnyFormOfGetOwnPropertyNames())
>                     return false;
>                 // FIXME: Indexed properties can be handled.
>                 // https://bugs.webkit.org/show_bug.cgi?id=185358
>@@ -357,7 +357,7 @@ JSC_DEFINE_HOST_FUNCTION(objectConstruct
>         targetCanPerformFastPut = false;
> 
>         PropertyNameArray properties(vm, PropertyNameMode::StringsAndSymbols, PrivateSymbolMode::Exclude);
>-        source->methodTable(vm)->getOwnPropertyNames(source, globalObject, properties, EnumerationMode(DontEnumPropertiesMode::Include));
>+        source->methodTable(vm)->getOwnPropertyNames(source, globalObject, properties, DontEnumPropertiesMode::Include);
>         RETURN_IF_EXCEPTION(scope, { });
> 
>         unsigned numProperties = properties.size();
>@@ -403,7 +403,7 @@ JSC_DEFINE_HOST_FUNCTION(objectConstruct
>     RETURN_IF_EXCEPTION(scope, { });
> 
>     PropertyNameArray properties(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
>-    target->methodTable(vm)->getOwnPropertyNames(target, globalObject, properties, EnumerationMode(DontEnumPropertiesMode::Include));
>+    target->methodTable(vm)->getOwnPropertyNames(target, globalObject, properties, DontEnumPropertiesMode::Include);
>     RETURN_IF_EXCEPTION(scope, { });
> 
>     unsigned index = 0;
>@@ -557,7 +557,7 @@ static JSValue defineProperties(JSGlobal
>     auto scope = DECLARE_THROW_SCOPE(vm);
> 
>     PropertyNameArray propertyNames(vm, PropertyNameMode::StringsAndSymbols, PrivateSymbolMode::Exclude);
>-    asObject(properties)->methodTable(vm)->getOwnPropertyNames(asObject(properties), globalObject, propertyNames, EnumerationMode(DontEnumPropertiesMode::Exclude));
>+    asObject(properties)->methodTable(vm)->getOwnPropertyNames(asObject(properties), globalObject, propertyNames, DontEnumPropertiesMode::Exclude);
>     RETURN_IF_EXCEPTION(scope, { });
>     size_t numProperties = propertyNames.size();
>     Vector<PropertyDescriptor> descriptors;
>@@ -648,7 +648,7 @@ bool setIntegrityLevel(JSGlobalObject* g
>         return false;
> 
>     PropertyNameArray properties(vm, PropertyNameMode::StringsAndSymbols, PrivateSymbolMode::Exclude);
>-    object->methodTable(vm)->getOwnPropertyNames(object, globalObject, properties, EnumerationMode(DontEnumPropertiesMode::Include));
>+    object->methodTable(vm)->getOwnPropertyNames(object, globalObject, properties, DontEnumPropertiesMode::Include);
>     RETURN_IF_EXCEPTION(scope, false);
> 
>     PropertyNameArray::const_iterator end = properties.end();
>@@ -695,7 +695,7 @@ bool testIntegrityLevel(JSGlobalObject* 
> 
>     // 6. Let keys be ? O.[[OwnPropertyKeys]]().
>     PropertyNameArray keys(vm, PropertyNameMode::StringsAndSymbols, PrivateSymbolMode::Exclude);
>-    object->methodTable(vm)->getOwnPropertyNames(object, globalObject, keys, EnumerationMode(DontEnumPropertiesMode::Include));
>+    object->methodTable(vm)->getOwnPropertyNames(object, globalObject, keys, DontEnumPropertiesMode::Include);
>     RETURN_IF_EXCEPTION(scope, { });
> 
>     // 7. For each element k of keys, do
>@@ -877,7 +877,7 @@ JSArray* ownPropertyKeys(JSGlobalObject*
>     }
> 
>     PropertyNameArray properties(vm, propertyNameMode, PrivateSymbolMode::Exclude);
>-    object->methodTable(vm)->getOwnPropertyNames(object, globalObject, properties, EnumerationMode(dontEnumPropertiesMode));
>+    object->methodTable(vm)->getOwnPropertyNames(object, globalObject, properties, dontEnumPropertiesMode);
>     RETURN_IF_EXCEPTION(scope, nullptr);
> 
>     if (propertyNameMode != PropertyNameMode::StringsAndSymbols) {
>Index: Source/JavaScriptCore/runtime/ProxyObject.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/ProxyObject.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/ProxyObject.cpp	(working copy)
>@@ -890,10 +890,9 @@ void ProxyObject::performGetOwnPropertyN
>     JSValue ownKeysMethod = handler->getMethod(globalObject, callData, makeIdentifier(vm, "ownKeys"), "'ownKeys' property of a Proxy's handler should be callable"_s);
>     RETURN_IF_EXCEPTION(scope, void());
>     JSObject* target = this->target();
>-    EnumerationMode enumerationMode(DontEnumPropertiesMode::Include);
>     if (ownKeysMethod.isUndefined()) {
>         scope.release();
>-        target->methodTable(vm)->getOwnPropertyNames(target, globalObject, propertyNames, enumerationMode);
>+        target->methodTable(vm)->getOwnPropertyNames(target, globalObject, propertyNames, DontEnumPropertiesMode::Include);
>         return;
>     }
> 
>@@ -946,7 +945,7 @@ void ProxyObject::performGetOwnPropertyN
>     RETURN_IF_EXCEPTION(scope, void());
> 
>     PropertyNameArray targetKeys(vm, PropertyNameMode::StringsAndSymbols, PrivateSymbolMode::Exclude);
>-    target->methodTable(vm)->getOwnPropertyNames(target, globalObject, targetKeys, enumerationMode);
>+    target->methodTable(vm)->getOwnPropertyNames(target, globalObject, targetKeys, DontEnumPropertiesMode::Include);
>     RETURN_IF_EXCEPTION(scope, void());
>     Vector<UniquedStringImpl*> targetConfigurableKeys;
>     Vector<UniquedStringImpl*> targetNonConfigurableKeys;
>@@ -1013,37 +1012,15 @@ void ProxyObject::performGetOwnEnumerabl
>     }
> }
> 
>-void ProxyObject::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNameArray, EnumerationMode enumerationMode)
>+void ProxyObject::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNameArray, DontEnumPropertiesMode mode)
> {
>     ProxyObject* thisObject = jsCast<ProxyObject*>(object);
>-    if (enumerationMode.includeDontEnumProperties())
>+    if (mode == DontEnumPropertiesMode::Include)
>         thisObject->performGetOwnPropertyNames(globalObject, propertyNameArray);
>     else
>         thisObject->performGetOwnEnumerablePropertyNames(globalObject, propertyNameArray);
> }
> 
>-void ProxyObject::getPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNameArray, EnumerationMode enumerationMode)
>-{
>-    NO_TAIL_CALLS();
>-    JSObject::getPropertyNames(object, globalObject, propertyNameArray, enumerationMode);
>-}
>-
>-void ProxyObject::getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode)
>-{
>-    RELEASE_ASSERT_NOT_REACHED();
>-}
>-
>-void ProxyObject::getStructurePropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode)
>-{
>-    // We should always go down the getOwnPropertyNames path.
>-    RELEASE_ASSERT_NOT_REACHED();
>-}
>-
>-void ProxyObject::getGenericPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode)
>-{
>-    RELEASE_ASSERT_NOT_REACHED();
>-}
>-
> bool ProxyObject::performSetPrototype(JSGlobalObject* globalObject, JSValue prototype, bool shouldThrowIfCantSet)
> {
>     NO_TAIL_CALLS();
>Index: Source/JavaScriptCore/runtime/ProxyObject.h
>===================================================================
>--- Source/JavaScriptCore/runtime/ProxyObject.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/ProxyObject.h	(working copy)
>@@ -34,7 +34,7 @@ class ProxyObject final : public JSNonFi
> public:
>     typedef JSNonFinalObject Base;
> 
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetCallData | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | OverridesGetPropertyNames | OverridesAnyFormOfGetPropertyNames | OverridesGetPrototype | ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnPropertyNames | OverridesGetPrototype | OverridesGetCallData | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | ProhibitsPropertyCaching;
> 
>     template<typename CellType, SubspaceAccess mode>
>     static IsoSubspace* subspaceFor(VM& vm)
>@@ -57,7 +57,6 @@ public:
>         if (isCallable)
>             flags |= (ImplementsHasInstance | ImplementsDefaultHasInstance);
>         Structure* result = Structure::create(vm, globalObject, prototype, TypeInfo(ProxyObjectType, flags), info(), NonArray | MayHaveIndexedAccessors);
>-        result->setIsQuickPropertyAccessAllowedForEnumeration(false);
>         RELEASE_ASSERT(!result->canAccessPropertiesQuicklyForEnumeration());
>         RELEASE_ASSERT(!result->canCachePropertyNameEnumerator(vm));
>         return result;
>@@ -89,11 +88,7 @@ private:
>     static bool preventExtensions(JSObject*, JSGlobalObject*);
>     static bool isExtensible(JSObject*, JSGlobalObject*);
>     static bool defineOwnProperty(JSObject*, JSGlobalObject*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
>-    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    static void getPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    static NO_RETURN_DUE_TO_CRASH void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    static NO_RETURN_DUE_TO_CRASH void getStructurePropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    static NO_RETURN_DUE_TO_CRASH void getGenericPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     static bool setPrototype(JSObject*, JSGlobalObject*, JSValue prototype, bool shouldThrowIfCantSet);
>     static JSValue getPrototype(JSObject*, JSGlobalObject*);
>     static void visitChildren(JSCell*, SlotVisitor&);
>Index: Source/JavaScriptCore/runtime/RegExpObject.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/RegExpObject.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/RegExpObject.cpp	(working copy)
>@@ -75,28 +75,11 @@ bool RegExpObject::deleteProperty(JSCell
>     return Base::deleteProperty(cell, globalObject, propertyName, slot);
> }
> 
>-void RegExpObject::getOwnNonIndexPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void RegExpObject::getOwnSpecialPropertyNames(JSObject*, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = globalObject->vm();
>-    if (mode.includeDontEnumProperties())
>+    if (mode == DontEnumPropertiesMode::Include)
>         propertyNames.add(vm.propertyNames->lastIndex);
>-    Base::getOwnNonIndexPropertyNames(object, globalObject, propertyNames, mode);
>-}
>-
>-void RegExpObject::getPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>-{
>-    VM& vm = globalObject->vm();
>-    if (mode.includeDontEnumProperties())
>-        propertyNames.add(vm.propertyNames->lastIndex);
>-    Base::getPropertyNames(object, globalObject, propertyNames, mode);
>-}
>-
>-void RegExpObject::getGenericPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>-{
>-    VM& vm = globalObject->vm();
>-    if (mode.includeDontEnumProperties())
>-        propertyNames.add(vm.propertyNames->lastIndex);
>-    Base::getGenericPropertyNames(object, globalObject, propertyNames, mode);
> }
> 
> bool RegExpObject::defineOwnProperty(JSObject* object, JSGlobalObject* globalObject, PropertyName propertyName, const PropertyDescriptor& descriptor, bool shouldThrow)
>Index: Source/JavaScriptCore/runtime/RegExpObject.h
>===================================================================
>--- Source/JavaScriptCore/runtime/RegExpObject.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/RegExpObject.h	(working copy)
>@@ -30,7 +30,7 @@ namespace JSC {
> class RegExpObject final : public JSNonFinalObject {
> public:
>     using Base = JSNonFinalObject;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetPropertyNames | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnSpecialPropertyNames;
> 
>     template<typename CellType, SubspaceAccess mode>
>     static IsoSubspace* subspaceFor(VM& vm)
>@@ -146,9 +146,7 @@ private:
>     }
> 
>     JS_EXPORT_PRIVATE static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
>-    JS_EXPORT_PRIVATE static void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    JS_EXPORT_PRIVATE static void getPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    JS_EXPORT_PRIVATE static void getGenericPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    JS_EXPORT_PRIVATE static void getOwnSpecialPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     JS_EXPORT_PRIVATE static bool defineOwnProperty(JSObject*, JSGlobalObject*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
> 
>     MatchResult matchInline(JSGlobalObject*, JSString*);
>Index: Source/JavaScriptCore/runtime/StringObject.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/StringObject.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/StringObject.cpp	(working copy)
>@@ -145,7 +145,7 @@ bool StringObject::deletePropertyByIndex
>     return JSObject::deletePropertyByIndex(thisObject, globalObject, i);
> }
> 
>-void StringObject::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void StringObject::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = globalObject->vm();
>     StringObject* thisObject = jsCast<StringObject*>(object);
>@@ -153,17 +153,11 @@ void StringObject::getOwnPropertyNames(J
>         int size = thisObject->internalValue()->length();
>         for (int i = 0; i < size; ++i)
>             propertyNames.add(Identifier::from(vm, i));
>+        thisObject->getOwnIndexedPropertyNames(globalObject, propertyNames, mode);
>     }
>-    return JSObject::getOwnPropertyNames(thisObject, globalObject, propertyNames, mode);
>-}
>-
>-void StringObject::getOwnNonIndexPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>-{
>-    VM& vm = globalObject->vm();
>-    StringObject* thisObject = jsCast<StringObject*>(object);
>-    if (mode.includeDontEnumProperties())
>+    if (mode == DontEnumPropertiesMode::Include)
>         propertyNames.add(vm.propertyNames->length);
>-    return JSObject::getOwnNonIndexPropertyNames(thisObject, globalObject, propertyNames, mode);
>+    thisObject->getOwnNonIndexPropertyNames(globalObject, propertyNames, mode);
> }
> 
> String StringObject::toStringName(const JSObject*, JSGlobalObject*)
>Index: Source/JavaScriptCore/runtime/StringObject.h
>===================================================================
>--- Source/JavaScriptCore/runtime/StringObject.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/StringObject.h	(working copy)
>@@ -28,7 +28,7 @@ namespace JSC {
> class StringObject : public JSWrapperObject {
> public:
>     using Base = JSWrapperObject;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnPropertyNames | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero;
> 
>     template<typename, SubspaceAccess mode>
>     static IsoSubspace* subspaceFor(VM& vm)
>@@ -59,8 +59,7 @@ public:
> 
>     JS_EXPORT_PRIVATE static bool deleteProperty(JSCell*, JSGlobalObject*, PropertyName, DeletePropertySlot&);
>     JS_EXPORT_PRIVATE static bool deletePropertyByIndex(JSCell*, JSGlobalObject*, unsigned propertyName);
>-    JS_EXPORT_PRIVATE static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>-    JS_EXPORT_PRIVATE static void getOwnNonIndexPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    JS_EXPORT_PRIVATE static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     JS_EXPORT_PRIVATE static bool defineOwnProperty(JSObject*, JSGlobalObject*, PropertyName, const PropertyDescriptor&, bool shouldThrow);
>     static String toStringName(const JSObject*, JSGlobalObject*);
> 
>Index: Source/JavaScriptCore/runtime/Structure.cpp
>===================================================================
>--- Source/JavaScriptCore/runtime/Structure.cpp	(revision 270932)
>+++ Source/JavaScriptCore/runtime/Structure.cpp	(working copy)
>@@ -194,32 +194,20 @@ void Structure::validateFlags()
>         && methodTable.doPutPropertySecurityCheck != JSCell::doPutPropertySecurityCheck;
>     RELEASE_ASSERT(overridesPutPropertySecurityCheck == typeInfo().hasPutPropertySecurityCheck());
> 
>-    bool overridesGetPropertyNames =
>-        methodTable.getPropertyNames != JSObject::getPropertyNames
>-        && methodTable.getPropertyNames != JSCell::getPropertyNames;
>     bool overridesGetOwnPropertyNames =
>         methodTable.getOwnPropertyNames != JSObject::getOwnPropertyNames
>         && methodTable.getOwnPropertyNames != JSCell::getOwnPropertyNames;
>-    bool overridesGetOwnNonIndexPropertyNames =
>-        methodTable.getOwnNonIndexPropertyNames != JSObject::getOwnNonIndexPropertyNames
>-        && methodTable.getOwnNonIndexPropertyNames != JSCell::getOwnNonIndexPropertyNames;
>-
>-    RELEASE_ASSERT(overridesGetPropertyNames == typeInfo().overridesGetPropertyNames());
>-
>-    // We can strengthen this into an equivalence test if there are no classes
>-    // that specifies this flag without overriding any of the forms of getPropertyNames.
>-    // FIXME: https://bugs.webkit.org/show_bug.cgi?id=212954
>-    if (overridesGetPropertyNames
>-        || overridesGetOwnPropertyNames
>-        || overridesGetOwnNonIndexPropertyNames)
>-        RELEASE_ASSERT(typeInfo().overridesAnyFormOfGetPropertyNames());
>+    RELEASE_ASSERT(overridesGetOwnPropertyNames == typeInfo().overridesGetOwnPropertyNames());
>+
>+    bool overridesGetOwnSpecialPropertyNames =
>+        methodTable.getOwnSpecialPropertyNames != JSObject::getOwnSpecialPropertyNames
>+        && methodTable.getOwnSpecialPropertyNames != JSCell::getOwnSpecialPropertyNames;
>+    RELEASE_ASSERT(overridesGetOwnSpecialPropertyNames == typeInfo().overridesGetOwnSpecialPropertyNames());
> 
>     bool overridesGetPrototype =
>         methodTable.getPrototype != static_cast<MethodTable::GetPrototypeFunctionPtr>(JSObject::getPrototype)
>         && methodTable.getPrototype != JSCell::getPrototype;
>-
>-    if (overridesGetPrototype)
>-        RELEASE_ASSERT(typeInfo().overridesGetPrototype());
>+    RELEASE_ASSERT(overridesGetPrototype == typeInfo().overridesGetPrototype());
> }
> #else
> inline void Structure::validateFlags() { }
>@@ -1203,7 +1191,7 @@ PropertyOffset Structure::attributeChang
>         });
> }
> 
>-void Structure::getPropertyNamesFromStructure(VM& vm, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void Structure::getPropertyNamesFromStructure(VM& vm, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     PropertyTable* table = ensurePropertyTableIfNotEmpty(vm);
>     if (!table)
>@@ -1213,7 +1201,7 @@ void Structure::getPropertyNamesFromStru
>     bool foundSymbol = false;
> 
>     auto checkDontEnumAndAdd = [&](PropertyTable::iterator iter) {
>-        if (!(iter->attributes & PropertyAttribute::DontEnum) || mode.includeDontEnumProperties()) {
>+        if (mode == DontEnumPropertiesMode::Include || !(iter->attributes & PropertyAttribute::DontEnum)) {
>             if (knownUnique)
>                 propertyNames.addUnchecked(iter->key);
>             else
>@@ -1489,6 +1477,8 @@ bool Structure::canAccessPropertiesQuick
>         return false;
>     if (isUncacheableDictionary())
>         return false;
>+    if (typeInfo().overridesGetOwnPropertyNames())
>+        return false;
>     return true;
> }
> 
>Index: Source/JavaScriptCore/runtime/Structure.h
>===================================================================
>--- Source/JavaScriptCore/runtime/Structure.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/Structure.h	(working copy)
>@@ -530,7 +530,7 @@ public:
>     void setCachedPropertyNames(VM&, CachedPropertyNamesKind, JSImmutableButterfly*);
>     bool canCacheOwnPropertyNames() const;
> 
>-    void getPropertyNamesFromStructure(VM&, PropertyNameArray&, EnumerationMode);
>+    void getPropertyNamesFromStructure(VM&, PropertyNameArray&, DontEnumPropertiesMode);
> 
>     JSValue cachedSpecialProperty(CachedSpecialPropertyKey key)
>     {
>Index: Source/JavaScriptCore/runtime/StructureInlines.h
>===================================================================
>--- Source/JavaScriptCore/runtime/StructureInlines.h	(revision 270932)
>+++ Source/JavaScriptCore/runtime/StructureInlines.h	(working copy)
>@@ -275,7 +275,7 @@ inline bool Structure::canCacheOwnProper
>         return false;
>     if (hasIndexedProperties(indexingType()))
>         return false;
>-    if (typeInfo().overridesAnyFormOfGetPropertyNames())
>+    if (typeInfo().overridesAnyFormOfGetOwnPropertyNames())
>         return false;
>     return true;
> }
>Index: Source/JavaScriptCore/tools/JSDollarVM.cpp
>===================================================================
>--- Source/JavaScriptCore/tools/JSDollarVM.cpp	(revision 270932)
>+++ Source/JavaScriptCore/tools/JSDollarVM.cpp	(working copy)
>@@ -543,7 +543,7 @@ static JSC_DECLARE_CUSTOM_GETTER(runtime
> class RuntimeArray : public JSArray {
> public:
>     typedef JSArray Base;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero;
> 
> IGNORE_WARNINGS_BEGIN("unused-const-variable")
>     static constexpr bool needsDestruction = false;
>Index: Source/WebCore/ChangeLog
>===================================================================
>--- Source/WebCore/ChangeLog	(revision 270932)
>+++ Source/WebCore/ChangeLog	(working copy)
>@@ -1,3 +1,37 @@
>+2020-12-17  Alexey Shvayka  <shvaikalesh@gmail.com>
>+
>+        [JSC] Simplify get*PropertyNames() methods and EnumerationMode
>+        https://bugs.webkit.org/show_bug.cgi?id=212954
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        Adjust for changes in JSC's MethodTable, TypeInfo, and EnumerationMode.
>+
>+        No new tests, no behavior change.
>+
>+        * animation/KeyframeEffect.cpp:
>+        (WebCore::processKeyframeLikeObject):
>+        * bindings/js/JSDOMConvertRecord.h:
>+        * bindings/js/JSDOMWindowCustom.cpp:
>+        (WebCore::JSDOMWindow::getOwnPropertyNames):
>+        * bindings/js/JSLocationCustom.cpp:
>+        (WebCore::JSLocation::getOwnPropertyNames):
>+        * bindings/js/JSRemoteDOMWindowCustom.cpp:
>+        (WebCore::JSRemoteDOMWindow::getOwnPropertyNames):
>+        * bindings/js/SerializedScriptValue.cpp:
>+        (WebCore::CloneSerializer::serialize):
>+        * bindings/scripts/CodeGeneratorJS.pm:
>+        (GenerateGetOwnPropertyNames):
>+        (GenerateHeader):
>+        * bindings/scripts/test/JS/*: Updated.
>+        * bridge/NP_jsobject.cpp:
>+        * bridge/runtime_array.cpp:
>+        (JSC::RuntimeArray::getOwnPropertyNames):
>+        * bridge/runtime_array.h:
>+        * bridge/runtime_object.cpp:
>+        (JSC::Bindings::RuntimeObject::getOwnPropertyNames):
>+        * bridge/runtime_object.h:
>+
> 2020-12-17  Rob Buis  <rbuis@igalia.com>
> 
>         Make FontCascade::CodePath an enum class
>Index: Source/WebCore/animation/KeyframeEffect.cpp
>===================================================================
>--- Source/WebCore/animation/KeyframeEffect.cpp	(revision 270932)
>+++ Source/WebCore/animation/KeyframeEffect.cpp	(working copy)
>@@ -238,7 +238,7 @@ static inline ExceptionOr<KeyframeEffect
> 
>     // 3. Let input properties be the result of calling the EnumerableOwnNames operation with keyframe input as the object.
>     PropertyNameArray inputProperties(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
>-    JSObject::getOwnPropertyNames(keyframesInput.get(), &lexicalGlobalObject, inputProperties, EnumerationMode());
>+    JSObject::getOwnPropertyNames(keyframesInput.get(), &lexicalGlobalObject, inputProperties, DontEnumPropertiesMode::Exclude);
> 
>     // 4. Make up a new list animation properties that consists of all of the properties that are in both input properties and animatable
>     //    properties, or which are in input properties and conform to the <custom-property-name> production.
>Index: Source/WebCore/bindings/js/JSDOMConvertRecord.h
>===================================================================
>--- Source/WebCore/bindings/js/JSDOMConvertRecord.h	(revision 270932)
>+++ Source/WebCore/bindings/js/JSDOMConvertRecord.h	(working copy)
>@@ -100,7 +100,7 @@ private:
>     
>         // 4. Let keys be ? O.[[OwnPropertyKeys]]().
>         JSC::PropertyNameArray keys(vm, JSC::PropertyNameMode::Strings, JSC::PrivateSymbolMode::Exclude);
>-        object->methodTable(vm)->getOwnPropertyNames(object, &lexicalGlobalObject, keys, JSC::EnumerationMode(JSC::DontEnumPropertiesMode::Include));
>+        object->methodTable(vm)->getOwnPropertyNames(object, &lexicalGlobalObject, keys, JSC::DontEnumPropertiesMode::Include);
> 
>         RETURN_IF_EXCEPTION(scope, { });
> 
>@@ -113,7 +113,7 @@ private:
> 
>             // 2. If desc is not undefined and desc.[[Enumerable]] is true:
> 
>-            // It's necessary to filter enumerable here rather than using the default EnumerationMode,
>+            // It's necessary to filter enumerable here rather than using DontEnumPropertiesMode::Exclude,
>             // to prevent an observable extra [[GetOwnProperty]] operation in the case of ProxyObject records.
>             if (didGetDescriptor && descriptor.enumerable()) {
>                 // 1. Let typedKey be key converted to an IDL value of type K.
>Index: Source/WebCore/bindings/js/JSDOMWindowCustom.cpp
>===================================================================
>--- Source/WebCore/bindings/js/JSDOMWindowCustom.cpp	(revision 270932)
>+++ Source/WebCore/bindings/js/JSDOMWindowCustom.cpp	(working copy)
>@@ -454,14 +454,14 @@ static void addScopedChildrenIndexes(JSG
> }
> 
> // https://html.spec.whatwg.org/#windowproxy-ownpropertykeys
>-void JSDOMWindow::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSDOMWindow::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     JSDOMWindow* thisObject = jsCast<JSDOMWindow*>(object);
> 
>     addScopedChildrenIndexes(*lexicalGlobalObject, thisObject->wrapped(), propertyNames);
> 
>     if (!BindingSecurity::shouldAllowAccessToDOMWindow(lexicalGlobalObject, thisObject->wrapped(), DoNotReportSecurityError)) {
>-        if (mode.includeDontEnumProperties())
>+        if (mode == DontEnumPropertiesMode::Include)
>             addCrossOriginOwnPropertyNames<CrossOriginObject::Window>(*lexicalGlobalObject, propertyNames);
>         return;
>     }
>Index: Source/WebCore/bindings/js/JSLocationCustom.cpp
>===================================================================
>--- Source/WebCore/bindings/js/JSLocationCustom.cpp	(revision 270932)
>+++ Source/WebCore/bindings/js/JSLocationCustom.cpp	(working copy)
>@@ -188,11 +188,11 @@ bool JSLocation::deletePropertyByIndex(J
>     return Base::deletePropertyByIndex(thisObject, lexicalGlobalObject, propertyName);
> }
> 
>-void JSLocation::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSLocation::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     JSLocation* thisObject = jsCast<JSLocation*>(object);
>     if (!BindingSecurity::shouldAllowAccessToDOMWindow(lexicalGlobalObject, thisObject->wrapped().window(), DoNotReportSecurityError)) {
>-        if (mode.includeDontEnumProperties())
>+        if (mode == DontEnumPropertiesMode::Include)
>             addCrossOriginOwnPropertyNames<CrossOriginObject::Location>(*lexicalGlobalObject, propertyNames);
>         return;
>     }
>Index: Source/WebCore/bindings/js/JSRemoteDOMWindowCustom.cpp
>===================================================================
>--- Source/WebCore/bindings/js/JSRemoteDOMWindowCustom.cpp	(revision 270932)
>+++ Source/WebCore/bindings/js/JSRemoteDOMWindowCustom.cpp	(working copy)
>@@ -100,11 +100,11 @@ bool JSRemoteDOMWindow::deletePropertyBy
>     return false;
> }
> 
>-void JSRemoteDOMWindow::getOwnPropertyNames(JSObject*, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSRemoteDOMWindow::getOwnPropertyNames(JSObject*, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     // FIXME: Add scoped children indexes.
> 
>-    if (mode.includeDontEnumProperties())
>+    if (mode == DontEnumPropertiesMode::Include)
>         addCrossOriginOwnPropertyNames<CrossOriginObject::Window>(*lexicalGlobalObject, propertyNames);
> }
> 
>Index: Source/WebCore/bindings/js/SerializedScriptValue.cpp
>===================================================================
>--- Source/WebCore/bindings/js/SerializedScriptValue.cpp	(revision 270932)
>+++ Source/WebCore/bindings/js/SerializedScriptValue.cpp	(working copy)
>@@ -1728,7 +1728,7 @@ SerializationReturnCode CloneSerializer:
>                     lengthStack.removeLast();
> 
>                     propertyStack.append(PropertyNameArray(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude));
>-                    array->methodTable(vm)->getOwnNonIndexPropertyNames(array, m_lexicalGlobalObject, propertyStack.last(), EnumerationMode());
>+                    array->getOwnNonIndexPropertyNames(m_lexicalGlobalObject, propertyStack.last(), DontEnumPropertiesMode::Exclude);
>                     if (propertyStack.last().size()) {
>                         write(NonIndexPropertiesTag);
>                         indexStack.append(0);
>@@ -1778,7 +1778,7 @@ SerializationReturnCode CloneSerializer:
>                 inputObjectStack.append(inObject);
>                 indexStack.append(0);
>                 propertyStack.append(PropertyNameArray(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude));
>-                inObject->methodTable(vm)->getOwnPropertyNames(inObject, m_lexicalGlobalObject, propertyStack.last(), EnumerationMode());
>+                inObject->methodTable(vm)->getOwnPropertyNames(inObject, m_lexicalGlobalObject, propertyStack.last(), DontEnumPropertiesMode::Exclude);
>             }
>             objectStartVisitMember:
>             FALLTHROUGH;
>@@ -1846,7 +1846,7 @@ SerializationReturnCode CloneSerializer:
>                     JSObject* object = inputObjectStack.last();
>                     ASSERT(jsDynamicCast<JSMap*>(vm, object));
>                     propertyStack.append(PropertyNameArray(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude));
>-                    object->methodTable(vm)->getOwnPropertyNames(object, m_lexicalGlobalObject, propertyStack.last(), EnumerationMode());
>+                    object->methodTable(vm)->getOwnPropertyNames(object, m_lexicalGlobalObject, propertyStack.last(), DontEnumPropertiesMode::Exclude);
>                     write(NonMapPropertiesTag);
>                     indexStack.append(0);
>                     goto objectStartVisitMember;
>@@ -1890,7 +1890,7 @@ SerializationReturnCode CloneSerializer:
>                     JSObject* object = inputObjectStack.last();
>                     ASSERT(jsDynamicCast<JSSet*>(vm, object));
>                     propertyStack.append(PropertyNameArray(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude));
>-                    object->methodTable(vm)->getOwnPropertyNames(object, m_lexicalGlobalObject, propertyStack.last(), EnumerationMode());
>+                    object->methodTable(vm)->getOwnPropertyNames(object, m_lexicalGlobalObject, propertyStack.last(), DontEnumPropertiesMode::Exclude);
>                     write(NonSetPropertiesTag);
>                     indexStack.append(0);
>                     goto objectStartVisitMember;
>Index: Source/WebCore/bindings/scripts/CodeGeneratorJS.pm
>===================================================================
>--- Source/WebCore/bindings/scripts/CodeGeneratorJS.pm	(revision 270932)
>+++ Source/WebCore/bindings/scripts/CodeGeneratorJS.pm	(working copy)
>@@ -1122,7 +1122,7 @@ sub GenerateGetOwnPropertyNames
>     my $namedGetterOperation = GetNamedGetterOperation($interface);
>     my $indexedGetterOperation = GetIndexedGetterOperation($interface);
>     
>-    push(@$outputArray, "void ${className}::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)\n");
>+    push(@$outputArray, "void ${className}::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)\n");
>     push(@$outputArray, "{\n");
>     if ($indexedGetterOperation || $namedGetterOperation) {
>         push(@$outputArray, "    VM& vm = JSC::getVM(lexicalGlobalObject);\n");
>@@ -1148,7 +1148,7 @@ sub GenerateGetOwnPropertyNames
>             push(@$outputArray, "    for (auto& propertyName : thisObject->wrapped().supportedPropertyNames())\n");
>             push(@$outputArray, "        propertyNames.add(Identifier::fromString(vm, propertyName));\n");
>         } else {
>-            push(@$outputArray, "    if (mode.includeDontEnumProperties()) {\n");
>+            push(@$outputArray, "    if (mode == DontEnumPropertiesMode::Include) {\n");
>             push(@$outputArray, "        for (auto& propertyName : thisObject->wrapped().supportedPropertyNames())\n");
>             push(@$outputArray, "            propertyNames.add(Identifier::fromString(vm, propertyName));\n");
>             push(@$outputArray, "    }\n");
>@@ -2980,8 +2980,8 @@ sub GenerateHeader
>     }
>     
>     if (InstanceOverridesGetOwnPropertyNames($interface)) {
>-        push(@headerContent, "    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());\n");
>-        $structureFlags{"JSC::OverridesAnyFormOfGetPropertyNames"} = 1;
>+        push(@headerContent, "    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);\n");
>+        $structureFlags{"JSC::OverridesGetOwnPropertyNames"} = 1;
>     }
>     
>     if (InstanceOverridesPut($interface)) {
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestEventTarget.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestEventTarget.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestEventTarget.cpp	(working copy)
>@@ -208,7 +208,7 @@ bool JSTestEventTarget::getOwnPropertySl
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestEventTarget::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestEventTarget::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestEventTarget*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestEventTarget.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestEventTarget.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestEventTarget.h	(working copy)
>@@ -43,7 +43,7 @@ public:
>     static TestEventTarget* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
> 
>     DECLARE_INFO;
> 
>@@ -66,7 +66,7 @@ public:
>         return static_cast<TestEventTarget&>(Base::wrapped());
>     }
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::MasqueradesAsUndefined | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::MasqueradesAsUndefined | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestEventTarget(JSC::Structure*, JSDOMGlobalObject&, Ref<TestEventTarget>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterNoIdentifier.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterNoIdentifier.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterNoIdentifier.cpp	(working copy)
>@@ -178,7 +178,7 @@ bool JSTestIndexedSetterNoIdentifier::ge
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestIndexedSetterNoIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestIndexedSetterNoIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestIndexedSetterNoIdentifier*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterNoIdentifier.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterNoIdentifier.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterNoIdentifier.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestIndexedSetterNoIdentifier* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestIndexedSetterNoIdentifier(JSC::Structure*, JSDOMGlobalObject&, Ref<TestIndexedSetterNoIdentifier>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterThrowingException.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterThrowingException.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterThrowingException.cpp	(working copy)
>@@ -178,7 +178,7 @@ bool JSTestIndexedSetterThrowingExceptio
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestIndexedSetterThrowingException::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestIndexedSetterThrowingException::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestIndexedSetterThrowingException*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterThrowingException.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterThrowingException.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterThrowingException.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestIndexedSetterThrowingException* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestIndexedSetterThrowingException(JSC::Structure*, JSDOMGlobalObject&, Ref<TestIndexedSetterThrowingException>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterWithIdentifier.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterWithIdentifier.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterWithIdentifier.cpp	(working copy)
>@@ -185,7 +185,7 @@ bool JSTestIndexedSetterWithIdentifier::
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestIndexedSetterWithIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestIndexedSetterWithIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestIndexedSetterWithIdentifier*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterWithIdentifier.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterWithIdentifier.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestIndexedSetterWithIdentifier.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestIndexedSetterWithIdentifier* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestIndexedSetterWithIdentifier(JSC::Structure*, JSDOMGlobalObject&, Ref<TestIndexedSetterWithIdentifier>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestLegacyOverrideBuiltIns.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestLegacyOverrideBuiltIns.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestLegacyOverrideBuiltIns.cpp	(working copy)
>@@ -199,7 +199,7 @@ bool JSTestLegacyOverrideBuiltIns::getOw
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestLegacyOverrideBuiltIns::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestLegacyOverrideBuiltIns::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestLegacyOverrideBuiltIns*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestLegacyOverrideBuiltIns.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestLegacyOverrideBuiltIns.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestLegacyOverrideBuiltIns.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestLegacyOverrideBuiltIns* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static void destroy(JSC::JSCell*);
> 
>     DECLARE_INFO;
>@@ -61,7 +61,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpure | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpure | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestLegacyOverrideBuiltIns(JSC::Structure*, JSDOMGlobalObject&, Ref<TestLegacyOverrideBuiltIns>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterNoIdentifier.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterNoIdentifier.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterNoIdentifier.cpp	(working copy)
>@@ -207,7 +207,7 @@ bool JSTestNamedAndIndexedSetterNoIdenti
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedAndIndexedSetterNoIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedAndIndexedSetterNoIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedAndIndexedSetterNoIdentifier*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterNoIdentifier.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterNoIdentifier.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterNoIdentifier.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedAndIndexedSetterNoIdentifier* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedAndIndexedSetterNoIdentifier(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedAndIndexedSetterNoIdentifier>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterThrowingException.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterThrowingException.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterThrowingException.cpp	(working copy)
>@@ -207,7 +207,7 @@ bool JSTestNamedAndIndexedSetterThrowing
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedAndIndexedSetterThrowingException::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedAndIndexedSetterThrowingException::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedAndIndexedSetterThrowingException*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterThrowingException.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterThrowingException.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterThrowingException.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedAndIndexedSetterThrowingException* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedAndIndexedSetterThrowingException(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedAndIndexedSetterThrowingException>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterWithIdentifier.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterWithIdentifier.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterWithIdentifier.cpp	(working copy)
>@@ -216,7 +216,7 @@ bool JSTestNamedAndIndexedSetterWithIden
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedAndIndexedSetterWithIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedAndIndexedSetterWithIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedAndIndexedSetterWithIdentifier*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterWithIdentifier.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterWithIdentifier.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedAndIndexedSetterWithIdentifier.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedAndIndexedSetterWithIdentifier* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedAndIndexedSetterWithIdentifier(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedAndIndexedSetterWithIdentifier>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterNoIdentifier.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterNoIdentifier.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterNoIdentifier.cpp	(working copy)
>@@ -190,7 +190,7 @@ bool JSTestNamedDeleterNoIdentifier::get
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedDeleterNoIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedDeleterNoIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedDeleterNoIdentifier*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterNoIdentifier.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterNoIdentifier.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterNoIdentifier.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedDeleterNoIdentifier* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool deleteProperty(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::DeletePropertySlot&);
>     static bool deletePropertyByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned);
>     static void destroy(JSC::JSCell*);
>@@ -63,7 +63,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestNamedDeleterNoIdentifier(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedDeleterNoIdentifier>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterThrowingException.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterThrowingException.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterThrowingException.cpp	(working copy)
>@@ -190,7 +190,7 @@ bool JSTestNamedDeleterThrowingException
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedDeleterThrowingException::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedDeleterThrowingException::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedDeleterThrowingException*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterThrowingException.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterThrowingException.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterThrowingException.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedDeleterThrowingException* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool deleteProperty(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::DeletePropertySlot&);
>     static bool deletePropertyByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned);
>     static void destroy(JSC::JSCell*);
>@@ -63,7 +63,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestNamedDeleterThrowingException(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedDeleterThrowingException>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIdentifier.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIdentifier.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIdentifier.cpp	(working copy)
>@@ -196,7 +196,7 @@ bool JSTestNamedDeleterWithIdentifier::g
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedDeleterWithIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedDeleterWithIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedDeleterWithIdentifier*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIdentifier.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIdentifier.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIdentifier.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedDeleterWithIdentifier* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool deleteProperty(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::DeletePropertySlot&);
>     static bool deletePropertyByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned);
>     static void destroy(JSC::JSCell*);
>@@ -63,7 +63,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestNamedDeleterWithIdentifier(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedDeleterWithIdentifier>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIndexedGetter.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIndexedGetter.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIndexedGetter.cpp	(working copy)
>@@ -207,7 +207,7 @@ bool JSTestNamedDeleterWithIndexedGetter
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedDeleterWithIndexedGetter::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedDeleterWithIndexedGetter::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedDeleterWithIndexedGetter*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIndexedGetter.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIndexedGetter.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedDeleterWithIndexedGetter.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedDeleterWithIndexedGetter* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool deleteProperty(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::DeletePropertySlot&);
>     static bool deletePropertyByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned);
>     static void destroy(JSC::JSCell*);
>@@ -63,7 +63,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestNamedDeleterWithIndexedGetter(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedDeleterWithIndexedGetter>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterCallWith.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterCallWith.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterCallWith.cpp	(working copy)
>@@ -190,7 +190,7 @@ bool JSTestNamedGetterCallWith::getOwnPr
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedGetterCallWith::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedGetterCallWith::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedGetterCallWith*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterCallWith.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterCallWith.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterCallWith.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedGetterCallWith* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static void destroy(JSC::JSCell*);
> 
>     DECLARE_INFO;
>@@ -61,7 +61,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestNamedGetterCallWith(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedGetterCallWith>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterNoIdentifier.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterNoIdentifier.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterNoIdentifier.cpp	(working copy)
>@@ -190,7 +190,7 @@ bool JSTestNamedGetterNoIdentifier::getO
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedGetterNoIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedGetterNoIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedGetterNoIdentifier*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterNoIdentifier.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterNoIdentifier.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterNoIdentifier.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedGetterNoIdentifier* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static void destroy(JSC::JSCell*);
> 
>     DECLARE_INFO;
>@@ -61,7 +61,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestNamedGetterNoIdentifier(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedGetterNoIdentifier>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterWithIdentifier.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterWithIdentifier.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterWithIdentifier.cpp	(working copy)
>@@ -196,7 +196,7 @@ bool JSTestNamedGetterWithIdentifier::ge
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedGetterWithIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedGetterWithIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedGetterWithIdentifier*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterWithIdentifier.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterWithIdentifier.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedGetterWithIdentifier.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedGetterWithIdentifier* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static void destroy(JSC::JSCell*);
> 
>     DECLARE_INFO;
>@@ -61,7 +61,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestNamedGetterWithIdentifier(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedGetterWithIdentifier>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterNoIdentifier.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterNoIdentifier.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterNoIdentifier.cpp	(working copy)
>@@ -190,7 +190,7 @@ bool JSTestNamedSetterNoIdentifier::getO
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedSetterNoIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedSetterNoIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedSetterNoIdentifier*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterNoIdentifier.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterNoIdentifier.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterNoIdentifier.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedSetterNoIdentifier* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedSetterNoIdentifier(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedSetterNoIdentifier>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterThrowingException.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterThrowingException.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterThrowingException.cpp	(working copy)
>@@ -190,7 +190,7 @@ bool JSTestNamedSetterThrowingException:
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedSetterThrowingException::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedSetterThrowingException::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedSetterThrowingException*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterThrowingException.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterThrowingException.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterThrowingException.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedSetterThrowingException* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedSetterThrowingException(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedSetterThrowingException>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIdentifier.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIdentifier.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIdentifier.cpp	(working copy)
>@@ -196,7 +196,7 @@ bool JSTestNamedSetterWithIdentifier::ge
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedSetterWithIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedSetterWithIdentifier::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedSetterWithIdentifier*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIdentifier.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIdentifier.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIdentifier.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedSetterWithIdentifier* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedSetterWithIdentifier(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedSetterWithIdentifier>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetter.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetter.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetter.cpp	(working copy)
>@@ -216,7 +216,7 @@ bool JSTestNamedSetterWithIndexedGetter:
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedSetterWithIndexedGetter::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedSetterWithIndexedGetter::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedSetterWithIndexedGetter*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetter.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetter.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetter.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedSetterWithIndexedGetter* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedSetterWithIndexedGetter(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedSetterWithIndexedGetter>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetterAndSetter.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetterAndSetter.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetterAndSetter.cpp	(working copy)
>@@ -216,7 +216,7 @@ bool JSTestNamedSetterWithIndexedGetterA
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedSetterWithIndexedGetterAndSetter::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedSetterWithIndexedGetterAndSetter::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedSetterWithIndexedGetterAndSetter*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetterAndSetter.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetterAndSetter.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithIndexedGetterAndSetter.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedSetterWithIndexedGetterAndSetter* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedSetterWithIndexedGetterAndSetter(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedSetterWithIndexedGetterAndSetter>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyOverrideBuiltIns.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyOverrideBuiltIns.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyOverrideBuiltIns.cpp	(working copy)
>@@ -190,7 +190,7 @@ bool JSTestNamedSetterWithLegacyOverride
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedSetterWithLegacyOverrideBuiltIns::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedSetterWithLegacyOverrideBuiltIns::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedSetterWithLegacyOverrideBuiltIns*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyOverrideBuiltIns.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyOverrideBuiltIns.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyOverrideBuiltIns.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedSetterWithLegacyOverrideBuiltIns* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpure | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpure | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedSetterWithLegacyOverrideBuiltIns(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedSetterWithLegacyOverrideBuiltIns>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeableProperties.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeableProperties.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeableProperties.cpp	(working copy)
>@@ -214,7 +214,7 @@ bool JSTestNamedSetterWithLegacyUnforgea
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedSetterWithLegacyUnforgeableProperties::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedSetterWithLegacyUnforgeableProperties::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedSetterWithLegacyUnforgeableProperties*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeableProperties.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeableProperties.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeableProperties.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedSetterWithLegacyUnforgeableProperties* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::HasStaticPropertyTable | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpureForPropertyAbsence | JSC::HasStaticPropertyTable | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedSetterWithLegacyUnforgeableProperties(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedSetterWithLegacyUnforgeableProperties>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns.cpp	(working copy)
>@@ -214,7 +214,7 @@ bool JSTestNamedSetterWithLegacyUnforgea
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns.h	(working copy)
>@@ -41,7 +41,7 @@ public:
>     static TestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static bool put(JSC::JSCell*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::JSValue, JSC::PutPropertySlot&);
>     static bool putByIndex(JSC::JSCell*, JSC::JSGlobalObject*, unsigned propertyName, JSC::JSValue, bool shouldThrow);
>     static bool defineOwnProperty(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, const JSC::PropertyDescriptor&, bool shouldThrow);
>@@ -64,7 +64,7 @@ public:
>     static JSC::IsoSubspace* subspaceForImpl(JSC::VM& vm);
>     static void analyzeHeap(JSCell*, JSC::HeapAnalyzer&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpure | JSC::HasStaticPropertyTable | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::GetOwnPropertySlotIsImpure | JSC::HasStaticPropertyTable | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot | JSC::ProhibitsPropertyCaching;
> protected:
>     JSTestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns(JSC::Structure*, JSDOMGlobalObject&, Ref<TestNamedSetterWithLegacyUnforgeablePropertiesAndLegacyOverrideBuiltIns>&&);
> 
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestObj.cpp
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestObj.cpp	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestObj.cpp	(working copy)
>@@ -2530,7 +2530,7 @@ bool JSTestObj::getOwnPropertySlotByInde
>     return JSObject::getOwnPropertySlotByIndex(object, lexicalGlobalObject, index, slot);
> }
> 
>-void JSTestObj::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void JSTestObj::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = JSC::getVM(lexicalGlobalObject);
>     auto* thisObject = jsCast<JSTestObj*>(object);
>Index: Source/WebCore/bindings/scripts/test/JS/JSTestObj.h
>===================================================================
>--- Source/WebCore/bindings/scripts/test/JS/JSTestObj.h	(revision 270932)
>+++ Source/WebCore/bindings/scripts/test/JS/JSTestObj.h	(working copy)
>@@ -44,7 +44,7 @@ public:
>     static TestObj* toWrapped(JSC::VM&, JSC::JSValue);
>     static bool getOwnPropertySlot(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyName, JSC::PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSC::JSObject*, JSC::JSGlobalObject*, unsigned propertyName, JSC::PropertySlot&);
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode = JSC::EnumerationMode());
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
>     static JSC::CallData getCallData(JSC::JSCell*);
> 
>     static void destroy(JSC::JSCell*);
>@@ -85,7 +85,7 @@ public:
>     static JSC::JSValue testStaticCustomPromiseFunction(JSC::JSGlobalObject&, JSC::CallFrame&, Ref<DeferredPromise>&&);
>     JSC::JSValue testCustomReturnsOwnPromiseFunction(JSC::JSGlobalObject&, JSC::CallFrame&);
> public:
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::HasStaticPropertyTable | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetCallData | JSC::OverridesGetOwnPropertySlot;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::HasStaticPropertyTable | JSC::InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | JSC::OverridesGetCallData | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetOwnPropertySlot;
> protected:
>     JSTestObj(JSC::Structure*, JSDOMGlobalObject&, Ref<TestObj>&&);
> 
>Index: Source/WebCore/bridge/NP_jsobject.cpp
>===================================================================
>--- Source/WebCore/bridge/NP_jsobject.cpp	(revision 270932)
>+++ Source/WebCore/bridge/NP_jsobject.cpp	(working copy)
>@@ -487,7 +487,7 @@ bool _NPN_Enumerate(NPP, NPObject* o, NP
>         JSGlobalObject* lexicalGlobalObject = globalObject;
>         PropertyNameArray propertyNames(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
> 
>-        obj->imp->methodTable(vm)->getPropertyNames(obj->imp, lexicalGlobalObject, propertyNames, EnumerationMode());
>+        obj->imp->getPropertyNames(lexicalGlobalObject, propertyNames, DontEnumPropertiesMode::Exclude);
>         unsigned size = static_cast<unsigned>(propertyNames.size());
>         // FIXME: This should really call NPN_MemAlloc but that's in WebKit
>         NPIdentifier* identifiers = static_cast<NPIdentifier*>(malloc(sizeof(NPIdentifier) * size));
>Index: Source/WebCore/bridge/runtime_array.cpp
>===================================================================
>--- Source/WebCore/bridge/runtime_array.cpp	(revision 270932)
>+++ Source/WebCore/bridge/runtime_array.cpp	(working copy)
>@@ -75,7 +75,7 @@ JSC_DEFINE_CUSTOM_GETTER(arrayLengthGett
>     return JSValue::encode(jsNumber(thisObject->getLength()));
> }
> 
>-void RuntimeArray::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode mode)
>+void RuntimeArray::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode mode)
> {
>     VM& vm = lexicalGlobalObject->vm();
>     RuntimeArray* thisObject = jsCast<RuntimeArray*>(object);
>@@ -83,10 +83,10 @@ void RuntimeArray::getOwnPropertyNames(J
>     for (unsigned i = 0; i < length; ++i)
>         propertyNames.add(Identifier::from(vm, i));
> 
>-    if (mode.includeDontEnumProperties())
>+    if (mode == DontEnumPropertiesMode::Include)
>         propertyNames.add(vm.propertyNames->length);
> 
>-    JSObject::getOwnPropertyNames(thisObject, lexicalGlobalObject, propertyNames, mode);
>+    thisObject->getOwnNonIndexPropertyNames(lexicalGlobalObject, propertyNames, mode);
> }
> 
> bool RuntimeArray::getOwnPropertySlot(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyName propertyName, PropertySlot& slot)
>Index: Source/WebCore/bridge/runtime_array.h
>===================================================================
>--- Source/WebCore/bridge/runtime_array.h	(revision 270932)
>+++ Source/WebCore/bridge/runtime_array.h	(working copy)
>@@ -35,7 +35,7 @@ namespace JSC {
> class RuntimeArray final : public JSArray {
> public:
>     using Base = JSArray;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | OverridesAnyFormOfGetPropertyNames;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnPropertyNames | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero;
>     static constexpr bool needsDestruction = true;
> 
>     template<typename CellType, JSC::SubspaceAccess>
>@@ -59,7 +59,7 @@ public:
>     ~RuntimeArray();
>     static void destroy(JSCell*);
> 
>-    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
>     static bool getOwnPropertySlot(JSObject*, JSGlobalObject*, PropertyName, PropertySlot&);
>     static bool getOwnPropertySlotByIndex(JSObject*, JSGlobalObject*, unsigned, PropertySlot&);
>     static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
>Index: Source/WebCore/bridge/runtime_object.cpp
>===================================================================
>--- Source/WebCore/bridge/runtime_object.cpp	(revision 270932)
>+++ Source/WebCore/bridge/runtime_object.cpp	(working copy)
>@@ -280,7 +280,7 @@ CallData RuntimeObject::getConstructData
>     return constructData;
> }
> 
>-void RuntimeObject::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, EnumerationMode)
>+void RuntimeObject::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNames, DontEnumPropertiesMode)
> {
>     VM& vm = lexicalGlobalObject->vm();
>     auto scope = DECLARE_THROW_SCOPE(vm);
>Index: Source/WebCore/bridge/runtime_object.h
>===================================================================
>--- Source/WebCore/bridge/runtime_object.h	(revision 270932)
>+++ Source/WebCore/bridge/runtime_object.h	(working copy)
>@@ -37,7 +37,7 @@ Exception* throwRuntimeObjectInvalidAcce
> class WEBCORE_EXPORT RuntimeObject : public JSNonFinalObject {
> public:
>     using Base = JSNonFinalObject;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesAnyFormOfGetPropertyNames | OverridesGetCallData;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | OverridesGetOwnPropertyNames | OverridesGetCallData;
>     static constexpr bool needsDestruction = true;
> 
>     template<typename CellType, JSC::SubspaceAccess>
>@@ -64,7 +64,7 @@ public:
>     static CallData getCallData(JSCell*);
>     static CallData getConstructData(JSCell*);
> 
>-    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, EnumerationMode);
>+    static void getOwnPropertyNames(JSObject*, JSGlobalObject*, PropertyNameArray&, DontEnumPropertiesMode);
> 
>     void invalidate();
> 
>Index: Source/WebKit/ChangeLog
>===================================================================
>--- Source/WebKit/ChangeLog	(revision 270932)
>+++ Source/WebKit/ChangeLog	(working copy)
>@@ -1,3 +1,20 @@
>+2020-12-17  Alexey Shvayka  <shvaikalesh@gmail.com>
>+
>+        [JSC] Simplify get*PropertyNames() methods and EnumerationMode
>+        https://bugs.webkit.org/show_bug.cgi?id=212954
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        Adjust for changes in JSC's MethodTable, TypeInfo, and EnumerationMode.
>+
>+        No new tests, no behavior change.
>+
>+        * WebProcess/Plugins/Netscape/JSNPObject.cpp:
>+        (WebKit::JSNPObject::getOwnPropertyNames):
>+        * WebProcess/Plugins/Netscape/JSNPObject.h:
>+        * WebProcess/Plugins/Netscape/NPJSObject.cpp:
>+        (WebKit::NPJSObject::enumerate):
>+
> 2020-12-17  Rob Buis  <rbuis@igalia.com>
> 
>         Make FontCascade::CodePath an enum class
>Index: Source/WebKit/WebProcess/Plugins/Netscape/JSNPObject.cpp
>===================================================================
>--- Source/WebKit/WebProcess/Plugins/Netscape/JSNPObject.cpp	(revision 270932)
>+++ Source/WebKit/WebProcess/Plugins/Netscape/JSNPObject.cpp	(working copy)
>@@ -425,7 +425,7 @@ bool JSNPObject::deleteProperty(JSGlobal
>     return true;
> }
> 
>-void JSNPObject::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNameArray, EnumerationMode)
>+void JSNPObject::getOwnPropertyNames(JSObject* object, JSGlobalObject* lexicalGlobalObject, PropertyNameArray& propertyNameArray, DontEnumPropertiesMode)
> {
>     VM& vm = lexicalGlobalObject->vm();
>     auto scope = DECLARE_THROW_SCOPE(vm);
>Index: Source/WebKit/WebProcess/Plugins/Netscape/JSNPObject.h
>===================================================================
>--- Source/WebKit/WebProcess/Plugins/Netscape/JSNPObject.h	(revision 270932)
>+++ Source/WebKit/WebProcess/Plugins/Netscape/JSNPObject.h	(working copy)
>@@ -44,7 +44,7 @@ class NPRuntimeObjectMap;
> class JSNPObject final : public JSC::JSDestructibleObject {
> public:
>     using Base = JSC::JSDestructibleObject;
>-    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::OverridesGetOwnPropertySlot | JSC::OverridesAnyFormOfGetPropertyNames | JSC::OverridesGetCallData;
>+    static constexpr unsigned StructureFlags = Base::StructureFlags | JSC::OverridesGetOwnPropertySlot | JSC::OverridesGetOwnPropertyNames | JSC::OverridesGetCallData;
> 
>     template<typename CellType, JSC::SubspaceAccess>
>     static JSC::IsoSubspace* subspaceFor(JSC::VM& vm)
>@@ -99,7 +99,7 @@ private:
> 
>     bool deleteProperty(JSC::JSGlobalObject*, NPIdentifier propertyName);
> 
>-    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::EnumerationMode);
>+    static void getOwnPropertyNames(JSC::JSObject*, JSC::JSGlobalObject*, JSC::PropertyNameArray&, JSC::DontEnumPropertiesMode);
> 
>     NPRuntimeObjectMap* m_objectMap;
>     NPObject* m_npObject;
>Index: Source/WebKit/WebProcess/Plugins/Netscape/NPJSObject.cpp
>===================================================================
>--- Source/WebKit/WebProcess/Plugins/Netscape/NPJSObject.cpp	(revision 270932)
>+++ Source/WebKit/WebProcess/Plugins/Netscape/NPJSObject.cpp	(working copy)
>@@ -253,7 +253,7 @@ bool NPJSObject::enumerate(NPIdentifier*
>     JSLockHolder lock(vm);
> 
>     PropertyNameArray propertyNames(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
>-    m_jsObject->methodTable(vm)->getPropertyNames(m_jsObject.get(), lexicalGlobalObject, propertyNames, EnumerationMode());
>+    m_jsObject->getPropertyNames(lexicalGlobalObject, propertyNames, DontEnumPropertiesMode::Exclude);
> 
>     NPIdentifier* nameIdentifiers = npnMemNewArray<NPIdentifier>(propertyNames.size());
> 
>Index: Source/WebKitLegacy/mac/ChangeLog
>===================================================================
>--- Source/WebKitLegacy/mac/ChangeLog	(revision 270932)
>+++ Source/WebKitLegacy/mac/ChangeLog	(working copy)
>@@ -1,3 +1,13 @@
>+2020-12-17  Alexey Shvayka  <shvaikalesh@gmail.com>
>+
>+        [JSC] Simplify get*PropertyNames() methods and EnumerationMode
>+        https://bugs.webkit.org/show_bug.cgi?id=212954
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        * Plugins/Hosted/NetscapePluginInstanceProxy.mm:
>+        (WebKit::NetscapePluginInstanceProxy::enumerate):
>+
> 2020-12-17  Rob Buis  <rbuis@igalia.com>
> 
>         Make FontCascade::CodePath an enum class
>Index: Source/WebKitLegacy/mac/Plugins/Hosted/NetscapePluginInstanceProxy.mm
>===================================================================
>--- Source/WebKitLegacy/mac/Plugins/Hosted/NetscapePluginInstanceProxy.mm	(revision 270932)
>+++ Source/WebKitLegacy/mac/Plugins/Hosted/NetscapePluginInstanceProxy.mm	(working copy)
>@@ -1273,7 +1273,7 @@ bool NetscapePluginInstanceProxy::enumer
>     JSGlobalObject* lexicalGlobalObject = frame->script().globalObject(pluginWorld());
>  
>     PropertyNameArray propertyNames(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
>-    object->methodTable(vm)->getPropertyNames(object, lexicalGlobalObject, propertyNames, EnumerationMode());
>+    object->getPropertyNames(lexicalGlobalObject, propertyNames, DontEnumPropertiesMode::Exclude);
> 
>     RetainPtr<NSMutableArray> array = adoptNS([[NSMutableArray alloc] init]);
>     for (unsigned i = 0; i < propertyNames.size(); i++) {

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Attachments on bug 212954: 416300 | 416418 | 416886 | 416888