Add fast-path inline keyword recognition #262
Merged
Conversation
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
This recognizes the 16 most frequent C keywords inline before falling back to hashmap lookup. This fast-path covers the majority of keyword cases in typical C code and reduces lookup overhead. - "if" keyword (40% of occurrences): 3 operations vs 3-4 hashmap ops - "return" keyword (21% of occurrences): 3 operations vs 3-4 hashmap ops - Expected 5-10% overall lexer performance improvement
This introduces a simple byte-by-byte memory comparison function, ensuring correctness and reliability in self-hosting environments.
DrXiao
approved these changes
Aug 25, 2025
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Outdated suggestions cannot be applied.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.
This recognizes the 16 most frequent C keywords inline before falling back to hashmap lookup. This fast-path covers the majority of keyword cases in typical C code and reduces lookup overhead.
Summary by Bito
This pull request introduces a fast-path inline keyword recognition feature for C, enhancing keyword lookup efficiency. It includes a new memory comparison function and improvements in lexer.c to directly recognize the 16 most frequent keywords, reducing hashmap reliance.