Refactor `HygieneEncodeContext` by aerooneqq · Pull Request #162520 · rust-lang/rust

aerooneqq · 2026-09-09T09:59:24Z

Some refactorings around HygieneEncodeContext with minor perf improvements, the most notable thing is that Locks were removed.

First part for #161450.

r? @petrochenkov

petrochenkov · 2026-09-09T14:13:41Z

This is missing some high level description.
What is the logic behind the changes in HygieneEncodeContext::encode?
Is the &'a -> Rc change necessary to get rid of locks, or is just to avoid lifetimes in signatures?
Some fields like latest_ctxts -> queued_ctxts apparently change their meaning but the descriptions are not updated.

petrochenkov · 2026-09-09T15:43:46Z

What is the logic behind the changes in HygieneEncodeContext::encode?

So the changes are to 1) reuse the capacity between the loop iterations (#162520 (comment)) and 2) move some map searches under the HygieneData lock (#162520 (comment)).

aerooneqq · 2026-09-10T11:15:24Z

Some fields like latest_ctxts -> queued_ctxts apparently change their meaning but the descriptions are not updated.

Renamed them back.

Is the &'a -> Rc change necessary to get rid of locks, or is just to avoid lifetimes in signatures?

There were borrowing problems because hygiene context is contained inside the encoder.

@rustbot ready

petrochenkov · 2026-09-10T13:32:03Z

r=me after addressing the remaining comments and squashing commits.
@bors delegate+
@rustbot author

rust-bors · 2026-09-10T13:32:07Z

✌️ @aerooneqq, you can now approve this pull request!

If @petrochenkov told you to "r=me" after making some further change, then please make that change and post @bors r=petrochenkov.

View changes since this delegation.

rustbot · 2026-09-10T13:32:08Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

aerooneqq · 2026-09-11T08:18:36Z

@bors squash

* Refactor `HygieneEncodeContext` * Review: remove comment outdated part * Review: return `raw_encode_syntax_context` as a free function * Review: small cleanups * Review: add comment about expansions data `Option` * Review: don't set explicit capacity * Review: return `queued` -> `latest` * Remove not needed changes * Fix `Rc` cloning * Return comment

rust-bors · 2026-09-11T08:18:57Z

🔨 10 commits were squashed into 69afc99.

aerooneqq · 2026-09-11T08:22:11Z

@bors r=petrochenkov

rust-bors · 2026-09-11T08:22:14Z

📌 Commit 69afc99 has been approved by petrochenkov

It is now in the queue for this repository.

petrochenkov · 2026-09-11T08:57:09Z

If bors squash is used, then it's better to use @bors squash msg="something" to avoid garbage in commit messages.

@petrochenkov

…nkov Refactor `HygieneEncodeContext` Some refactorings around `HygieneEncodeContext` with minor perf improvements, the most notable thing is that `Lock`s were removed. First part for rust-lang#161450. r? @petrochenkov

@petrochenkov

…nkov Refactor `HygieneEncodeContext` Some refactorings around `HygieneEncodeContext` with minor perf improvements, the most notable thing is that `Lock`s were removed. First part for rust-lang#161450. r? @petrochenkov

…uwer Rollup of 10 pull requests Successful merges: - #162126 (Rename various resolving functions for consistency, and document them) - #162520 (Refactor `HygieneEncodeContext`) - #154373 (Skip linting unused braces for FunctionArg and MethodArg context for 2024 later ) - #160023 (Refactor the way cg_ssa handles indirect returns (returns via `sret`) — Take 2) - #161482 (Use attribute parser for `#[non_exhaustive]` attribute check) - #161867 (deeper `rustc_builtin_macros` cleanups) - #162099 (small refactor of doc attribute arguments warnings) - #162541 (split `macroless_generic_const_args` in two) - #162549 (The fuchsia team maintains `riscv64gc-unknown-fuchsia`) - #162577 (Fix `i686-pc-windows-msvc` platform support docs and target spec metadata)

rust-bors · 2026-09-11T10:45:08Z

⌛ Testing commit 69afc99 with merge f3f47c1...

Workflow: https://github.com/rust-lang/rust/actions/runs/34590729157

@petrochenkov

Refactor `HygieneEncodeContext` Some refactorings around `HygieneEncodeContext` with minor perf improvements, the most notable thing is that `Lock`s were removed. First part for #161450. r? @petrochenkov

@petrochenkov

…nkov Refactor `HygieneEncodeContext` Some refactorings around `HygieneEncodeContext` with minor perf improvements, the most notable thing is that `Lock`s were removed. First part for rust-lang#161450. r? @petrochenkov

JonathanBrouwer · 2026-09-11T10:47:24Z

@bors yield
Yielding to enclosing rollup

rust-bors · 2026-09-11T10:47:28Z

Auto build was cancelled. Cancelled workflows:

https://github.com/rust-lang/rust/actions/runs/34590729157

The next pull request likely to be tested is #162631.

…uwer Rollup of 11 pull requests Successful merges: - #162520 (Refactor `HygieneEncodeContext`) - #154373 (Skip linting unused braces for FunctionArg and MethodArg context for 2024 later ) - #160023 (Refactor the way cg_ssa handles indirect returns (returns via `sret`) — Take 2) - #160860 (Implement arbitrary casts in custom mir) - #161482 (Use attribute parser for `#[non_exhaustive]` attribute check) - #161867 (deeper `rustc_builtin_macros` cleanups) - #162099 (small refactor of doc attribute arguments warnings) - #162541 (split `macroless_generic_const_args` in two) - #162549 (The fuchsia team maintains `riscv64gc-unknown-fuchsia`) - #162577 (Fix `i686-pc-windows-msvc` platform support docs and target spec metadata) - #162624 (regression test for opaque field projection in closure capture)

@petrochenkov

Rollup merge of #162520 - aerooneqq:hygiene-perf, r=petrochenkov Refactor `HygieneEncodeContext` Some refactorings around `HygieneEncodeContext` with minor perf improvements, the most notable thing is that `Lock`s were removed. First part for #161450. r? @petrochenkov

rust-timer · 2026-09-11T18:37:58Z

Note

This PR was benchmarked as part of triage of its containing rollup: triage URL.

Finished benchmarking commit (9b2b438): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.2%	[-0.2%, -0.1%]	2
Improvements ✅ (secondary)	-0.2%	[-0.2%, -0.1%]	2
All ❌✅ (primary)	-0.2%	[-0.2%, -0.1%]	2

Max RSS (memory usage)

This perf run didn't have relevant results for this metric.

Cycles

This perf run didn't have relevant results for this metric.

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: missing data
Artifact size: 407.63 MiB -> 406.93 MiB (-0.17%)

rustbot assigned petrochenkov Sep 9, 2026

petrochenkov reviewed Sep 9, 2026

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Comment thread compiler/rustc_span/src/hygiene.rs Outdated

Comment thread compiler/rustc_span/src/hygiene.rs Outdated

Comment thread compiler/rustc_span/src/hygiene.rs

petrochenkov reviewed Sep 9, 2026

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petrochenkov added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 9, 2026

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Comment thread compiler/rustc_span/src/hygiene.rs

Comment thread compiler/rustc_span/src/hygiene.rs

rustbot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Sep 10, 2026

rustbot added the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Sep 10, 2026

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rust-bors Bot force-pushed the hygiene-perf branch from c0911fe to 69afc99 Compare September 11, 2026 08:18

rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 11, 2026

JonathanBrouwer mentioned this pull request Sep 11, 2026

Rollup of 7 pull requests #162627

Closed

JonathanBrouwer mentioned this pull request Sep 11, 2026

Rollup of 10 pull requests #162629

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JonathanBrouwer mentioned this pull request Sep 11, 2026

Rollup of 11 pull requests #162631

Merged

Zalathar mentioned this pull request Sep 11, 2026

Rollup of 11 pull requests #162632

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rust-bors Bot merged commit 70410fe into rust-lang:main Sep 11, 2026
13 of 14 checks passed

rustbot added this to the 1.100.0 milestone Sep 11, 2026

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Overall result: ✅ improvements - no action needed

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