diff options
Diffstat (limited to 'lib/spack/external/jinja2/optimizer.py')
| -rw-r--r-- | lib/spack/external/jinja2/optimizer.py | 60 |
1 files changed, 26 insertions, 34 deletions
diff --git a/lib/spack/external/jinja2/optimizer.py b/lib/spack/external/jinja2/optimizer.py index 65ab3ceb71..7bc78c4524 100644 --- a/lib/spack/external/jinja2/optimizer.py +++ b/lib/spack/external/jinja2/optimizer.py @@ -1,23 +1,15 @@ # -*- 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. """ - jinja2.optimizer - ~~~~~~~~~~~~~~~~ - - The jinja optimizer is currently trying to constant fold a few expressions - and modify the AST in place so that it should be easier to evaluate it. - - 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 scoping. - - The solution would be a second syntax tree that has the scoping rules stored. - - :copyright: (c) 2017 by the Jinja Team. - :license: BSD. -""" -from jinja2 import nodes -from jinja2.visitor import NodeTransformer +from . import nodes +from .visitor import NodeTransformer def optimize(node, environment): @@ -28,22 +20,22 @@ def optimize(node, environment): class Optimizer(NodeTransformer): - def __init__(self, environment): self.environment = environment - def fold(self, node, eval_ctx=None): - """Do constant folding.""" - node = self.generic_visit(node) - try: - return nodes.Const.from_untrusted(node.as_const(eval_ctx), - lineno=node.lineno, - environment=self.environment) - except nodes.Impossible: - return node - - visit_Add = visit_Sub = visit_Mul = visit_Div = visit_FloorDiv = \ - visit_Pow = visit_Mod = visit_And = visit_Or = visit_Pos = visit_Neg = \ - visit_Not = visit_Compare = visit_Getitem = visit_Getattr = visit_Call = \ - visit_Filter = visit_Test = visit_CondExpr = fold - del fold + 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 |