[Python-Dev] Fast access to builtins (original) (raw)

Raymond Hettinger python@rcn.com
Thu, 27 Mar 2003 19:35:20 -0500

[Jack Diederich]

The behavior of a program under -O should be as similar as possible to normal operation. This would break that for some programs. A per-file pragma directive would work.

[Skip Montanero]

This is clearly a semantic change, so I'd like to see a different command line flag control this behavior

[M.-A. Lemburg]

Using the -O for this is not a working possibility. -OO is reserved for optimizations which can change semantics, but even there, I'd rather like a per-module switch than a command line switch.

That makes good sense.
Are you guys thinking of something like this:

fastbuiltins = True # optimize all subsequent defs in the module

[Jack Diederich]

The downside of a pragma module or keyword would be what people try to add to it later.

Ideally, enabling the pragma would also trigger warnings when the module shadows a builtin.

[M.-A. Lemburg]

BTW, why not have a new opcode for symbols in the builtins and then only tweak the opcode implementation instead of having the compiler generate different code ?

Either way results in changing one opcode/oparg pair, so I don't see how having a new opcode helps. At some point, the name has to be looked-up and a reference to it stored. Afterwards, LOAD_CONST is all that is needed to fetch the reference.

Raymond Hettinger