We're slower than the competition, and a profile shows 82% of time at least spent in JS code. There's some taking stub calls to deal with DOM getters, lots of SetElem, Arguments, GetElem, NewInitObject, etc stub calls. FixupArity, TypeOf stubs, NewArray. And 18% of the time is in mjit-generated code, too. The Arguments thing us 7% of the time here (mostly the malloc, actually), and shows up in all the Prototype stuff.
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