On 11/13/13 12:18 PM, Kevin Ballard wrote:
The only penalty this approach has (that comes to mind) over the single-inheritance model is that, because of the loss of the prefix property, any field access on the trait object itself will require looking up the field offset in the virtual table. But trait objects already use the virtual table for everything else, and the actual trait implementations don’t require this, so I don’t think it’s problematic to require a virtual table lookup on trait object field access.
I think it is. This is a performance cost over C++ that is just too risky. Note that browser reflow is very much gated on the ability to load and store fields from a constant offset. I think we stand a good chance of losing to the competition if we do this.
Patrick _______________________________________________ Rust-dev mailing list [email protected] https://mail.mozilla.org/listinfo/rust-dev
