Optimize the parser's last token handling. #36527
Merged
Conversation
This file contains 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
The parser currently makes a heap copy of the last token in four cases: identifiers, paths, doc comments, and commas. The identifier and interpolation cases are unused, and for doc comments and commas we only need to record their presence, not their value. This commit consolidates the last token handling and avoids the unnecessary copies by replacing `last_token`, `last_token_eof`, and `last_token_interpolated` with a new field `last_token_kind`. This simplifies the parser slightly and speeds up parsing on some files by 3--4%.
|
Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @sfackler (or someone else) soon. If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes. Please see the contribution instructions for more information. |
|
@nnethercote Nice -- thanks for the PR! |
|
📌 Commit 8075d54 has been approved by |
bors
added a commit
that referenced
this pull request
Sep 18, 2016
Optimize the parser's last token handling. The parser currently makes a heap copy of the last token in four cases: identifiers, paths, doc comments, and commas. The identifier and interpolation cases are unused, and for doc comments and commas we only need to record their presence, not their value. This commit consolidates the last token handling and avoids the unnecessary copies by replacing `last_token`, `last_token_eof`, and `last_token_interpolated` with a new field `last_token_kind`. This simplifies the parser slightly and speeds up parsing on some files by 3--4%.
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.
The parser currently makes a heap copy of the last token in four cases:
identifiers, paths, doc comments, and commas. The identifier and
interpolation cases are unused, and for doc comments and commas we only
need to record their presence, not their value.
This commit consolidates the last token handling and avoids the
unnecessary copies by replacing
last_token,last_token_eof, andlast_token_interpolatedwith a new fieldlast_token_kind. Thissimplifies the parser slightly and speeds up parsing on some files by
3--4%.