Cache properties whose fget contains only LOAD_ATTR_INSTANCE

[tekknolagi]

property.fget is immutable once set.

class C:
  @property
  def foo(self):
    return self.value

def test(c):
  return c.foo

[tekknolagi]

TODO:

• Test
• Probably re-use LOAD_ATTR_INSTANCE instead of adding a new opcode

[tekknolagi]

Add insertDependencyForTypeLookupInMro for callee instance attr name

[tekknolagi]

TODO: publish benchmark as a separate PR so we can get benchmark result in PR

[tekknolagi]

Cache the attr name of the actual attribute?

[github-actions]

Summary

Metric	Average	Best	Worst	Notes
cg_instructions	-2.7%	loadproperty -32.0%	2to3 0.1%	typically < 0.2% noise

Base vs. New

benchmark	cg_instructions
2to3	0.1%
bench_base64	0.0%
bench_pickle	0.0%
deltablue	0.0%
fannkuch	0.0%
go	-0.0%
loadproperty	-32.0%
nbody	0.0%
nqueens	0.0%
pyflate	0.0%
pystone	-0.0%
richards	-0.0%

CPython vs New

benchmark	cg_instructions
2to3	-4.8%
bench_base64	-37.4%
bench_pickle	-18.5%
deltablue	-64.3%
fannkuch	0.5%
go	-63.4%
loadproperty	-82.7%
nbody	23.5%
nqueens	45.8%
pyflate	-30.5%
pystone	-71.1%
richards	-79.6%

Base

benchmark	cg_instructions
2to3	2,437,984,702
bench_base64	3,016,853,185
bench_pickle	3,377,774,416
deltablue	1,472,158,721
fannkuch	5,623,197,818
go	1,927,882,136
loadproperty	443,760,487
nbody	9,628,673,650
nqueens	3,227,852,691
pyflate	10,052,587,706
pystone	1,150,090,576
richards	985,754,940

New

benchmark	cg_instructions
2to3	2,439,990,582
bench_base64	3,016,873,889
bench_pickle	3,377,893,895
deltablue	1,472,176,190
fannkuch	5,623,213,178
go	1,927,840,034
loadproperty	301,769,456
nbody	9,628,682,252
nqueens	3,227,858,881
pyflate	10,052,590,992
pystone	1,150,090,164
richards	985,754,474

CPython

benchmark	cg_instructions
2to3	2,563,286,110
bench_base64	4,817,679,149
bench_pickle	4,144,846,344
deltablue	4,118,266,915
fannkuch	5,594,122,992
go	5,264,552,729
loadproperty	1,747,785,109
nbody	7,793,834,961
nqueens	2,213,999,000
pyflate	14,465,386,488
pystone	3,981,027,045
richards	4,820,470,723