Skip to content

regexp: allow patterns with no alternates to be one-pass #48748

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Closed
wants to merge 3 commits into from
Closed

regexp: allow patterns with no alternates to be one-pass #48748

wants to merge 3 commits into from

Conversation

bboreham
Copy link
Contributor

@bboreham bboreham commented Oct 2, 2021 •
edited
Loading

Check whether a regex has any 'alt' instructions before rejecting it as one-pass.
Previously ^abc would run the backtrack matcher.

I tried to make the comment match what the code does now.

Updates #21463

name                            old time/op    new time/op    delta
Find-8                             167ns ± 1%     170ns ± 3%     ~     (p=0.500 n=5+5)
FindAllNoMatches-8                88.8ns ± 5%    87.3ns ± 0%     ~     (p=0.095 n=5+5)
FindString-8                       166ns ± 3%     164ns ± 0%     ~     (p=0.063 n=5+5)
FindSubmatch-8                     191ns ± 1%     191ns ± 0%     ~     (p=0.556 n=4+5)
FindStringSubmatch-8               183ns ± 0%     182ns ± 0%   -0.43%  (p=0.048 n=5+5)
Literal-8                         50.3ns ± 0%    50.1ns ± 0%   -0.40%  (p=0.016 n=5+4)
NotLiteral-8                       914ns ± 0%     927ns ± 7%     ~     (p=0.730 n=5+5)
MatchClass-8                      1.20µs ± 1%    1.22µs ± 6%     ~     (p=0.738 n=5+5)
MatchClass_InRange-8              1.20µs ± 6%    1.21µs ± 6%     ~     (p=0.548 n=5+5)
ReplaceAll-8                       796ns ± 0%     792ns ± 0%   -0.51%  (p=0.032 n=5+5)
AnchoredLiteralShortNonMatch-8    41.0ns ± 2%    34.2ns ± 2%  -16.47%  (p=0.008 n=5+5)
AnchoredLiteralLongNonMatch-8     53.3ns ± 0%    34.3ns ± 3%  -35.74%  (p=0.008 n=5+5)
AnchoredShortMatch-8              74.0ns ± 2%    75.8ns ± 0%   +2.46%  (p=0.032 n=5+4)
AnchoredLongMatch-8                146ns ± 3%      76ns ± 1%  -48.12%  (p=0.008 n=5+5)
OnePassShortA-8                    424ns ± 0%     423ns ± 0%     ~     (p=0.222 n=5+4)
NotOnePassShortA-8                 373ns ± 1%     375ns ± 2%     ~     (p=0.690 n=5+5)
OnePassShortB-8                    315ns ± 2%     308ns ± 0%   -2.12%  (p=0.008 n=5+5)
NotOnePassShortB-8                 244ns ± 3%     239ns ± 0%     ~     (p=0.476 n=5+5)
OnePassLongPrefix-8               61.6ns ± 2%    60.9ns ± 0%   -1.13%  (p=0.016 n=5+4)
OnePassLongNotPrefix-8             236ns ± 3%     230ns ± 0%     ~     (p=0.143 n=5+5)

@google-cla google-cla bot added the cla: yes Used by googlebot to label PRs as having a valid CLA. The text of this label should not change. label Oct 2, 2021
@gopherbot
Copy link
Contributor

This PR (HEAD: 6ce55f1) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/go/+/353711 to see it.

Tip: You can toggle comments from me using the comments slash command (e.g. /comments off)
See the Wiki page for more info

@gopherbot
Copy link
Contributor

Message from Ingo Oeser:

Patch Set 3:

(2 comments)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Bryan Boreham:

Patch Set 3:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

This PR (HEAD: d0f1fd6) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/go/+/353711 to see it.

Tip: You can toggle comments from me using the comments slash command (e.g. /comments off)
See the Wiki page for more info

@bboreham bboreham mentioned this pull request Oct 9, 2021
Open
@gopherbot
Copy link
Contributor

Message from Bryan Boreham:

Patch Set 4:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Brad Fitzpatrick:

Patch Set 4:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

This PR (HEAD: 96f04b5) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/go/+/353711 to see it.

Tip: You can toggle comments from me using the comments slash command (e.g. /comments off)
See the Wiki page for more info

@gopherbot
Copy link
Contributor

Message from Bryan Boreham:

Patch Set 5:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Brad Fitzpatrick:

Patch Set 5: Run-TryBot+1 Code-Review+1

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Gopher Robot:

Patch Set 5:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Gopher Robot:

Patch Set 5:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Gopher Robot:

Patch Set 5: TryBot-Result-1

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Russ Cox:

Patch Set 5: Code-Review+2 Hold+1

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Daniel Martí:

Patch Set 5: Code-Review+1

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

This PR (HEAD: 0d22e6b) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/go/+/353711 to see it.

Tip: You can toggle comments from me using the comments slash command (e.g. /comments off)
See the Wiki page for more info

@gopherbot
Copy link
Contributor

Message from Dmitri Shuralyov:

Patch Set 6:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Daniel Martí:

Patch Set 6: Code-Review+1

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Ingo Oeser:

Patch Set 3:

(2 comments)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Bryan Boreham:

Patch Set 3:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Bryan Boreham:

Patch Set 4:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Brad Fitzpatrick:

Patch Set 4:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Bryan Boreham:

Patch Set 5:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Brad Fitzpatrick:

Patch Set 5: Run-TryBot+1 Code-Review+1

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Gopher Robot:

Patch Set 5:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Gopher Robot:

Patch Set 5:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Gopher Robot:

Patch Set 5: TryBot-Result-1

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Russ Cox:

Patch Set 5: Code-Review+2 Hold+1

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Daniel Martí:

Patch Set 5: Code-Review+1

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Dmitri Shuralyov:

Patch Set 6:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Daniel Martí:

Patch Set 6: Code-Review+1

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Bryan Boreham:

Patch Set 6:

(2 comments)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

This PR (HEAD: e9e0c29) has been imported to Gerrit for code review.

Please visit Gerrit at https://go-review.googlesource.com/c/go/+/353711.

Important tips:

  • Don't comment on this PR. All discussion takes place in Gerrit.
  • You need a Gmail or other Google account to log in to Gerrit.
  • To change your code in response to feedback:
    • Push a new commit to the branch used by your GitHub PR.
    • A new "patch set" will then appear in Gerrit.
    • Respond to each comment by marking as Done in Gerrit if implemented as suggested. You can alternatively write a reply.
    • Critical: you must click the blue Reply button near the top to publish your Gerrit responses.
    • Multiple commits in the PR will be squashed by GerritBot.
  • The title and description of the GitHub PR are used to construct the final commit message.
    • Edit these as needed via the GitHub web interface (not via Gerrit or git).
    • You should word wrap the PR description at ~76 characters unless you need longer lines (e.g., for tables or URLs).
  • See the Sending a change via GitHub and Reviews sections of the Contribution Guide as well as the FAQ for details.

@gopherbot
Copy link
Contributor

Message from t hepudds:

Patch Set 7: Commit-Queue+1

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Go LUCI:

Patch Set 7:

Dry run: CV is trying the patch.

Bot data: {"action":"start","triggered_at":"2024-05-27T18:37:12Z","revision":"be1ae4ab4ecbe8bb2c9e4d566dc9d030ca4ddec1"}

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from t hepudds:

Patch Set 7: -Commit-Queue

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Go LUCI:

Patch Set 7:

This CL has passed the run

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Go LUCI:

Patch Set 7: LUCI-TryBot-Result+1

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Ian Lance Taylor:

Patch Set 7:

(1 comment)

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Dmitri Shuralyov:

Patch Set 7: Code-Review+1

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Ian Lance Taylor:

Patch Set 8: Auto-Submit+1 Commit-Queue+1

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Go LUCI:

Patch Set 8:

Dry run: CV is trying the patch.

Bot data: {"action":"start","triggered_at":"2024-07-24T00:36:29Z","revision":"d8f6484ca36ad46b2764a609e87d90c0f19fd587"}

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Ian Lance Taylor:

Patch Set 8: -Commit-Queue

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Go LUCI:

Patch Set 8:

This CL has passed the run

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

@gopherbot
Copy link
Contributor

Message from Go LUCI:

Patch Set 8: LUCI-TryBot-Result+1

Please don’t reply on this GitHub thread. Visit golang.org/cl/353711.
After addressing review feedback, remember to publish your drafts!

gopherbot pushed a commit that referenced this pull request Jul 24, 2024
@bboreham @gopherbot
regexp: allow patterns with no alternates to be one-pass
c5430dc 
Check whether a regex has any 'alt' instructions before rejecting it as one-pass.
Previously `^abc` would run the backtrack matcher.

I tried to make the comment match what the code does now.

Updates #21463

```
name                            old time/op    new time/op    delta
Find-8                             167ns ± 1%     170ns ± 3%     ~     (p=0.500 n=5+5)
FindAllNoMatches-8                88.8ns ± 5%    87.3ns ± 0%     ~     (p=0.095 n=5+5)
FindString-8                       166ns ± 3%     164ns ± 0%     ~     (p=0.063 n=5+5)
FindSubmatch-8                     191ns ± 1%     191ns ± 0%     ~     (p=0.556 n=4+5)
FindStringSubmatch-8               183ns ± 0%     182ns ± 0%   -0.43%  (p=0.048 n=5+5)
Literal-8                         50.3ns ± 0%    50.1ns ± 0%   -0.40%  (p=0.016 n=5+4)
NotLiteral-8                       914ns ± 0%     927ns ± 7%     ~     (p=0.730 n=5+5)
MatchClass-8                      1.20µs ± 1%    1.22µs ± 6%     ~     (p=0.738 n=5+5)
MatchClass_InRange-8              1.20µs ± 6%    1.21µs ± 6%     ~     (p=0.548 n=5+5)
ReplaceAll-8                       796ns ± 0%     792ns ± 0%   -0.51%  (p=0.032 n=5+5)
AnchoredLiteralShortNonMatch-8    41.0ns ± 2%    34.2ns ± 2%  -16.47%  (p=0.008 n=5+5)
AnchoredLiteralLongNonMatch-8     53.3ns ± 0%    34.3ns ± 3%  -35.74%  (p=0.008 n=5+5)
AnchoredShortMatch-8              74.0ns ± 2%    75.8ns ± 0%   +2.46%  (p=0.032 n=5+4)
AnchoredLongMatch-8                146ns ± 3%      76ns ± 1%  -48.12%  (p=0.008 n=5+5)
OnePassShortA-8                    424ns ± 0%     423ns ± 0%     ~     (p=0.222 n=5+4)
NotOnePassShortA-8                 373ns ± 1%     375ns ± 2%     ~     (p=0.690 n=5+5)
OnePassShortB-8                    315ns ± 2%     308ns ± 0%   -2.12%  (p=0.008 n=5+5)
NotOnePassShortB-8                 244ns ± 3%     239ns ± 0%     ~     (p=0.476 n=5+5)
OnePassLongPrefix-8               61.6ns ± 2%    60.9ns ± 0%   -1.13%  (p=0.016 n=5+4)
OnePassLongNotPrefix-8             236ns ± 3%     230ns ± 0%     ~     (p=0.143 n=5+5)
```

Change-Id: I8a94b53bc761cd7ec89923c905ec8baaaa58a5fd
GitHub-Last-Rev: e9e0c29
GitHub-Pull-Request: #48748
Reviewed-on: https://go-review.googlesource.com/c/go/+/353711
Reviewed-by: Daniel Martí <[email protected]>
Reviewed-by: Russ Cox <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Commit-Queue: Ian Lance Taylor <[email protected]>
Reviewed-by: Brad Fitzpatrick <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
@gopherbot
Copy link
Contributor

This PR is being closed because golang.org/cl/353711 has been merged.

@gopherbot gopherbot closed this Jul 24, 2024
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers
No reviews
Assignees
No one assigned
Labels
cla: yes Used by googlebot to label PRs as having a valid CLA. The text of this label should not change.
Projects
None yet
Milestone
No milestone
Development

Successfully merging this pull request may close these issues.
2 participants
@bboreham @gopherbot