Repository navigation
Avoid building typing generics at runtime in cast() calls - #203
Open
Shamsidinkhon wants to merge 1 commit into
Open
Shamsidinkhon wants to merge 1 commit into
Shamsidinkhon wants to merge 1 commit into
Conversation
This branch has not been deployed
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
evaluation.py calls typing.cast(X[...], value) on the evaluator's hot paths: comparisons, &&/||, unary operators, variable resolution, list/map literals and macros. cast() returns its value unchanged, but Python still evaluates the first argument on every call, so the subscripted type is rebuilt each time a node is visited.
Rebuilding is expensive when the type contains Result or celtypes.Value. Subscripting a generic goes through typing's internal lru_cache, and even a cache hit has to hash the arguments. Union, generic aliases and ForwardRef all implement hash in pure Python and don't store the result. Result is a 26-member union of 11 ForwardRefs, 14 Type[ForwardRef(...)] and two classes. So one hash(Result) makes 38 Python-level hash calls, and Tuple[Result, Result] makes 76.