bpo-43563 : Introduce dedicated opcodes for super calls

[vladima]

Add LOAD_METHOD_SUPER and LOAD_ATTR_SUPER opcodes to optimize method calls and attribute lookups when receiver is super().

https://bugs.python.org/issue43563

[gvanrossum]

See question on bpo -- why is this important? Do you have performance data to back up that this is an important optimization?

[github-actions]

This PR is stale because it has been open for 30 days with no activity.

[gvanrossum]

Unless you come up with some benchmark numbers, unfortunately we will have to close this PR. I'll give you a week to let us know what you'd like to do. If you need more time to benchmark, just let us know -- but if we don't hear from you after a week we'll close it. If you change your mind later or you're on vacation or something like that, I will still be notified of comments added to the issue after it's closed, so don't hesitate to say something!

[markshannon]

I'm interested to see how this compares with adaptive specialization of PEP 659.

The expression super().attr compiles with this PR as:

          LOAD_DEREF               0 (__class__)
          LOAD_FAST                  0 (self)
          LOAD_ATTR_SUPER   1 ((1, True))

on main this compiles as:

         CALL_FUNCTION            0
         LOAD_ATTR                1 (attr)

So main has a (small) advantage in dispatching.
The question is, can a specialized form of CALL_FUNCTION 0; LOAD_ATTR match the custom opcodes.

Assuming we specialize both CALL_FUNCTION and LOAD_ATTR I think it can.
There will be the overhead of creating the super() object, but the specializer has more context than the static compiler and should be able to do a much better job on the attribute lookup.

[carljm]

This is superseded by #103497.