Varia's website
https://varia.zone
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
42 lines
1.4 KiB
42 lines
1.4 KiB
2 weeks ago
|
# -*- coding: utf-8 -*-
|
||
|
|
"""The optimizer tries to constant fold expressions and modify the AST
|
||
|
|
in place so that it should be faster to evaluate.
|
||
|
|
|
||
|
|
Because the AST does not contain all the scoping information and the
|
||
|
|
compiler has to find that out, we cannot do all the optimizations we
|
||
|
|
want. For example, loop unrolling doesn't work because unrolled loops
|
||
|
|
would have a different scope. The solution would be a second syntax tree
|
||
|
|
that stored the scoping rules.
|
||
|
|
"""
|
||
|
|
from . import nodes
|
||
|
|
from .visitor import NodeTransformer
|
||
|
|
|
||
|
|
|
||
|
|
def optimize(node, environment):
|
||
|
|
"""The context hint can be used to perform an static optimization
|
||
|
|
based on the context given."""
|
||
|
|
optimizer = Optimizer(environment)
|
||
|
|
return optimizer.visit(node)
|
||
|
|
|
||
|
|
|
||
|
|
class Optimizer(NodeTransformer):
|
||
|
|
def __init__(self, environment):
|
||
|
|
self.environment = environment
|
||
|
|
|
||
|
|
def generic_visit(self, node, *args, **kwargs):
|
||
|
|
node = super(Optimizer, self).generic_visit(node, *args, **kwargs)
|
||
|
|
|
||
|
|
# Do constant folding. Some other nodes besides Expr have
|
||
|
|
# as_const, but folding them causes errors later on.
|
||
|
|
if isinstance(node, nodes.Expr):
|
||
|
|
try:
|
||
|
|
return nodes.Const.from_untrusted(
|
||
|
|
node.as_const(args[0] if args else None),
|
||
|
|
lineno=node.lineno,
|
||
|
|
environment=self.environment,
|
||
|
|
)
|
||
|
|
except nodes.Impossible:
|
||
|
|
pass
|
||
|
|
|
||
|
|
return node
|