Such optimizations are only true for receivers. If you have different prototypes all over the place, your code is going is not going to stay monomorphic. For every distinct prototype there's at least unique hidden class; given that the prototype link is hardwired in the hidden class.
regards, Toon On Tue, Aug 27, 2013 at 6:40 PM, Cris Perdue <[email protected]> wrote: > Performance optimization advice from the V8 team emphasizes initializing > properties to objects in constructors, and always in the same order (for > example http://www.youtube.com/watch?v=UJPdhx5zTaw). The explanation is > that this way each instance belongs to the same hidden class. > > What if you have fairly computation-intensive code that uses subclassing > and polymorphism? In this case method lookups need to go through the > prototype object for the instances. Once execution gets to the > type-specific method, life should be good again because that code always > receives a "this" and arguments of the same type at each invocation. (The > type-specific method code is typically fairly short and quick to execute in > my software.) > > My question is, to what degree should we expect a similar principle to > apply, that prototypes for subclasses should have the same members and the > members should be added to each subclass in the same order? Will this make > the compiler recognize the prototypes as belonging to the same hidden class > and make a big contribution to fast method lookup? Will method lookup code > tend to be inlined? Is it OK that the prototypes are all directly instances > of Object, and not some application-specific class? > > Thanks much for any insights here. > > -Cris > > -- > -- > v8-users mailing list > [email protected] > http://groups.google.com/group/v8-users > --- > You received this message because you are subscribed to the Google Groups > "v8-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- -- v8-users mailing list [email protected] http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
