| Index: src/elements.cc | 
| diff --git a/src/elements.cc b/src/elements.cc | 
| index a00cd249e76279b256d29bbbe1084574190fc03c..ac63b75888b26bc45cc88d0bbf926a9cecb39a55 100644 | 
| --- a/src/elements.cc | 
| +++ b/src/elements.cc | 
| @@ -620,7 +620,7 @@ class ElementsAccessorBase : public ElementsAccessor { | 
| Handle<JSObject> obj, | 
| uint32_t key, | 
| Handle<FixedArrayBase> backing_store) { | 
| -    if (key < ElementsAccessorSubclass::GetCapacityImpl(backing_store)) { | 
| +    if (key < ElementsAccessorSubclass::GetCapacityImpl(obj, backing_store)) { | 
| return BackingStore::get(Handle<BackingStore>::cast(backing_store), key); | 
| } else { | 
| return backing_store->GetIsolate()->factory()->the_hole_value(); | 
| @@ -638,7 +638,7 @@ class ElementsAccessorBase : public ElementsAccessor { | 
| Handle<JSObject> obj, | 
| uint32_t key, | 
| Handle<FixedArrayBase> backing_store) { | 
| -    if (key >= ElementsAccessorSubclass::GetCapacityImpl(backing_store)) { | 
| +    if (key >= ElementsAccessorSubclass::GetCapacityImpl(obj, backing_store)) { | 
| return ABSENT; | 
| } | 
| return | 
| @@ -751,7 +751,7 @@ class ElementsAccessorBase : public ElementsAccessor { | 
|  | 
| // Optimize if 'other' is empty. | 
| // We cannot optimize if 'this' is empty, as other may have holes. | 
| -    uint32_t len1 = ElementsAccessorSubclass::GetCapacityImpl(from); | 
| +    uint32_t len1 = ElementsAccessorSubclass::GetCapacityImpl(holder, from); | 
| if (len1 == 0) return to; | 
|  | 
| Isolate* isolate = from->GetIsolate(); | 
| @@ -817,12 +817,14 @@ class ElementsAccessorBase : public ElementsAccessor { | 
| } | 
|  | 
| protected: | 
| -  static uint32_t GetCapacityImpl(Handle<FixedArrayBase> backing_store) { | 
| +  static uint32_t GetCapacityImpl(Handle<JSObject> holder, | 
| +                                  Handle<FixedArrayBase> backing_store) { | 
| return backing_store->length(); | 
| } | 
|  | 
| -  uint32_t GetCapacity(Handle<FixedArrayBase> backing_store) final { | 
| -    return ElementsAccessorSubclass::GetCapacityImpl(backing_store); | 
| +  uint32_t GetCapacity(Handle<JSObject> holder, | 
| +                       Handle<FixedArrayBase> backing_store) final { | 
| +    return ElementsAccessorSubclass::GetCapacityImpl(holder, backing_store); | 
| } | 
|  | 
| static uint32_t GetKeyForIndexImpl(Handle<FixedArrayBase> backing_store, | 
| @@ -1260,7 +1262,7 @@ class TypedElementsAccessor | 
| Handle<JSObject> obj, | 
| uint32_t key, | 
| Handle<FixedArrayBase> backing_store) { | 
| -    if (key < AccessorClass::GetCapacityImpl(backing_store)) { | 
| +    if (key < AccessorClass::GetCapacityImpl(obj, backing_store)) { | 
| return BackingStore::get(Handle<BackingStore>::cast(backing_store), key); | 
| } else { | 
| return backing_store->GetIsolate()->factory()->undefined_value(); | 
| @@ -1271,9 +1273,8 @@ class TypedElementsAccessor | 
| Handle<JSObject> obj, | 
| uint32_t key, | 
| Handle<FixedArrayBase> backing_store) { | 
| -    return | 
| -        key < AccessorClass::GetCapacityImpl(backing_store) | 
| -          ? NONE : ABSENT; | 
| +    return key < AccessorClass::GetCapacityImpl(obj, backing_store) ? NONE | 
| +                                                                    : ABSENT; | 
| } | 
|  | 
| MUST_USE_RESULT static MaybeHandle<Object> SetLengthImpl( | 
| @@ -1293,10 +1294,16 @@ class TypedElementsAccessor | 
|  | 
| static bool HasElementImpl(Handle<JSObject> holder, uint32_t key, | 
| Handle<FixedArrayBase> backing_store) { | 
| -    uint32_t capacity = | 
| -        AccessorClass::GetCapacityImpl(backing_store); | 
| +    uint32_t capacity = AccessorClass::GetCapacityImpl(holder, backing_store); | 
| return key < capacity; | 
| } | 
| + | 
| +  static uint32_t GetCapacityImpl(Handle<JSObject> holder, | 
| +                                  Handle<FixedArrayBase> backing_store) { | 
| +    Handle<JSArrayBufferView> view = Handle<JSArrayBufferView>::cast(holder); | 
| +    if (view->WasNeutered()) return 0; | 
| +    return backing_store->length(); | 
| +  } | 
| }; | 
|  | 
|  | 
| @@ -1632,12 +1639,13 @@ class SloppyArgumentsElementsAccessor : public ElementsAccessorBase< | 
| UNREACHABLE(); | 
| } | 
|  | 
| -  static uint32_t GetCapacityImpl(Handle<FixedArrayBase> backing_store) { | 
| +  static uint32_t GetCapacityImpl(Handle<JSObject> holder, | 
| +                                  Handle<FixedArrayBase> backing_store) { | 
| Handle<FixedArray> parameter_map = Handle<FixedArray>::cast(backing_store); | 
| Handle<FixedArrayBase> arguments( | 
| FixedArrayBase::cast(parameter_map->get(1))); | 
| return Max(static_cast<uint32_t>(parameter_map->length() - 2), | 
| -               ForArray(arguments)->GetCapacity(arguments)); | 
| +               ForArray(arguments)->GetCapacity(holder, arguments)); | 
| } | 
|  | 
| static uint32_t GetKeyForIndexImpl(Handle<FixedArrayBase> dict, | 
|  |