Resolver: split module resolutions into local and external resolutions by LorrensP-2158466 · Pull Request #160099 · rust-lang/rust

LorrensP-2158466 · 2026-07-28T18:49:15Z

This pr splits the resolution table for local and external modules, with the external table being wrapped in a OnceLock, because only 1 thread may create that table in parallel resolution.

r? @petrochenkov

petrochenkov · 2026-07-28T21:37:27Z

@bors try @rust-timer queue

…<try> Resolver: split module resolutions into local and external resolutions

rust-bors · 2026-07-28T23:45:46Z

☀️ Try build successful (CI)
Build commit: 5fd6574 (5fd657436197e7acfa920d848f00e619d7da2390)
Base parent: e19d321 (e19d321c06479c6fd77533582b0d5a86651f1be3)

rust-timer · 2026-07-29T00:29:49Z

Finished benchmarking commit (5fd6574): comparison URL.

Overall result: ❌ regressions - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@rustbot label: -S-waiting-on-perf -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)	0.3%	[0.2%, 0.4%]	8
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (secondary -0.7%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	5.3%	[5.3%, 5.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.7%	[-5.4%, -2.0%]	2
All ❌✅ (primary)	-	-	0

Cycles

Results (primary -1.4%, secondary -2.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.5%	[2.7%, 4.2%]	2
Improvements ✅ (primary)	-1.4%	[-1.4%, -1.4%]	1
Improvements ✅ (secondary)	-4.0%	[-6.1%, -2.3%]	6
All ❌✅ (primary)	-1.4%	[-1.4%, -1.4%]	1

Binary size

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

Bootstrap: 490.165s -> 490.132s (-0.01%)
Artifact size: 388.34 MiB -> 390.34 MiB (0.52%)

LorrensP-2158466 · 2026-07-29T08:05:38Z

Increased cycle count is expected due to OnceLock doing a synchronized load of its state, but its less than expected. I don't think it would benefit from having a dynamic synchronized version like Lock.

petrochenkov · 2026-07-29T08:51:01Z

include-blob is irrelevant noise in this case, that benchmark doesn't even have modules, and replacing Once with OnceLock shouldn't be a regression.

petrochenkov · 2026-07-29T10:12:52Z

 }

-type Resolutions<'ra> = CmRefCell<FxIndexMap<BindingKey, NameResolutionRef<'ra>>>;
+type ResolutionTable<'ra> = CmRefCell<FxIndexMap<BindingKey, NameResolutionRef<'ra>>>;


The extern version of the table doesn't need CmRefCell, because it's never mutated.
But you'll have to either dismantle fn resolutions, or introduce something like CmRef to avoid it.

View changes since the review

I'll try it next.

petrochenkov · 2026-07-29T10:13:18Z

r=me after addressing #160099 (comment).
@rustbot author

rustbot · 2026-07-29T10:13:23Z

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

… having a `OnceLock` around it for parallel import resolution

LorrensP-2158466 · 2026-07-29T12:42:02Z

r=me after addressing

Can't do that :D, @rustbot ready.

petrochenkov · 2026-07-29T12:48:45Z

@bors r+ rollup

rust-bors · 2026-07-29T12:48:48Z

📌 Commit 580253e has been approved by petrochenkov

It is now in the queue for this repository.

@petrochenkov

…lutions, r=petrochenkov Resolver: split module resolutions into local and external resolutions Part of rust-lang#158845. This pr splits the resolution table for local and external modules, with the external table being wrapped in a `OnceLock`, because only 1 thread may create that table in parallel resolution. r? @petrochenkov

@petrochenkov

…lutions, r=petrochenkov Resolver: split module resolutions into local and external resolutions Part of rust-lang#158845. This pr splits the resolution table for local and external modules, with the external table being wrapped in a `OnceLock`, because only 1 thread may create that table in parallel resolution. r? @petrochenkov

Rollup of 17 pull requests Successful merges: - #159014 ([rustdoc] Do not take `doc(cfg())` into account when filtering doctests) - #159130 (a bit optimize four-digit chunks in integer formatting) - #159592 (core: implement bounded random sampling) - #159898 (Add intrinsic-test alias and set sample rate) - #158247 (hermit/fs: Return `unsupported()` instead of `from_raw_os_error(22)`) - #158649 (Hermit: fix `readdir()` ) - #159049 (Avoid ICE in From/TryFrom cast suggestion when encountering HRTBs) - #160053 (test: add test suite for the 85681 issue) - #160087 (Add regression test for nested associated-type projection ICE) - #160090 (rustc_resolve: Further reduce mutability in resolver) - #160099 (Resolver: split module resolutions into local and external resolutions) - #160106 (Add suggestions for `must_implement_one_of`) - #160117 (Remove unnecessary format usage) - #160134 (Work around Wine bug 60084 by calling WSAStartup at most once) - #160142 (bootstrap: remove use-lld config alias) - #160148 (Rename `errors.rs` file to `diagnostics.rs` (15/N)) - #160151 (Mark a doctest as requiring unwinding)

@petrochenkov

…lutions, r=petrochenkov Resolver: split module resolutions into local and external resolutions Part of rust-lang#158845. This pr splits the resolution table for local and external modules, with the external table being wrapped in a `OnceLock`, because only 1 thread may create that table in parallel resolution. r? @petrochenkov

Rollup of 18 pull requests Successful merges: - #159130 (a bit optimize four-digit chunks in integer formatting) - #159592 (core: implement bounded random sampling) - #159898 (Add intrinsic-test alias and set sample rate) - #158247 (hermit/fs: Return `unsupported()` instead of `from_raw_os_error(22)`) - #158649 (Hermit: fix `readdir()` ) - #159049 (Avoid ICE in From/TryFrom cast suggestion when encountering HRTBs) - #160053 (test: add test suite for the 85681 issue) - #160087 (Add regression test for nested associated-type projection ICE) - #160090 (rustc_resolve: Further reduce mutability in resolver) - #160099 (Resolver: split module resolutions into local and external resolutions) - #160106 (Add suggestions for `must_implement_one_of`) - #160117 (Remove unnecessary format usage) - #160134 (Work around Wine bug 60084 by calling WSAStartup at most once) - #160139 (iter: specialize Take::count using advance_by) - #160142 (bootstrap: remove use-lld config alias) - #160148 (Rename `errors.rs` file to `diagnostics.rs` (15/N)) - #160151 (Mark a doctest as requiring unwinding) - #160166 (Use correct feature gates for `f16`/`f128` `From` impls)

@petrochenkov

…lutions, r=petrochenkov Resolver: split module resolutions into local and external resolutions Part of rust-lang#158845. This pr splits the resolution table for local and external modules, with the external table being wrapped in a `OnceLock`, because only 1 thread may create that table in parallel resolution. r? @petrochenkov

…uwer Rollup of 18 pull requests Successful merges: - #159898 (Add intrinsic-test alias and set sample rate) - #158247 (hermit/fs: Return `unsupported()` instead of `from_raw_os_error(22)`) - #158649 (Hermit: fix `readdir()` ) - #158693 (Add type-check to offload intrinisc calls) - #159049 (Avoid ICE in From/TryFrom cast suggestion when encountering HRTBs) - #159411 ([rustdoc] Correctly handle output options with --show-coverage) - #160053 (test: add test suite for the 85681 issue) - #160087 (Add regression test for nested associated-type projection ICE) - #160090 (rustc_resolve: Further reduce mutability in resolver) - #160099 (Resolver: split module resolutions into local and external resolutions) - #160106 (Add suggestions for `must_implement_one_of`) - #160117 (Remove unnecessary format usage) - #160134 (Work around Wine bug 60084 by calling WSAStartup at most once) - #160139 (iter: specialize Take::count using advance_by) - #160142 (bootstrap: remove use-lld config alias) - #160148 (Rename `errors.rs` file to `diagnostics.rs` (15/N)) - #160151 (Mark a doctest as requiring unwinding) - #160166 (Use correct feature gates for `f16`/`f128` `From` impls)

Rollup of 20 pull requests Successful merges: - #157669 (cfi: add diag mode support) - #158247 (hermit/fs: Return `unsupported()` instead of `from_raw_os_error(22)`) - #158649 (Hermit: fix `readdir()` ) - #158693 (Add type-check to offload intrinisc calls) - #159049 (Avoid ICE in From/TryFrom cast suggestion when encountering HRTBs) - #159411 ([rustdoc] Correctly handle output options with --show-coverage) - #160053 (test: add test suite for the 85681 issue) - #160087 (Add regression test for nested associated-type projection ICE) - #160090 (rustc_resolve: Further reduce mutability in resolver) - #160099 (Resolver: split module resolutions into local and external resolutions) - #160101 (Add missing `needs-unwind` annotation to `add-spawn-hook-reentrancy-159923` test) - #160106 (Add suggestions for `must_implement_one_of`) - #160117 (Remove unnecessary format usage) - #160134 (Work around Wine bug 60084 by calling WSAStartup at most once) - #160139 (iter: specialize Take::count using advance_by) - #160142 (bootstrap: remove use-lld config alias) - #160148 (Rename `errors.rs` file to `diagnostics.rs` (15/N)) - #160151 (Mark a doctest as requiring unwinding) - #160166 (Use correct feature gates for `f16`/`f128` `From` impls) - #160178 (Remove unused `va_start` intrinsic)

@petrochenkov

Rollup merge of #160099 - LorrensP-2158466:split-module-resolutions, r=petrochenkov Resolver: split module resolutions into local and external resolutions Part of #158845. This pr splits the resolution table for local and external modules, with the external table being wrapped in a `OnceLock`, because only 1 thread may create that table in parallel resolution. r? @petrochenkov

rustbot assigned petrochenkov Jul 28, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jul 28, 2026

This comment has been minimized.

Sign in to view

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jul 28, 2026

This comment has been minimized.

Sign in to view

rust-bors Bot pushed a commit that referenced this pull request Jul 28, 2026

Auto merge of #160099 - LorrensP-2158466:split-module-resolutions, r=…

5fd6574

…<try> Resolver: split module resolutions into local and external resolutions

This comment has been minimized.

Sign in to view

rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jul 29, 2026

petrochenkov reviewed Jul 29, 2026

View reviewed changes

rustbot 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 Jul 29, 2026

split module resolutions into local and external types, with external…

580253e

… having a `OnceLock` around it for parallel import resolution

LorrensP-2158466 force-pushed the split-module-resolutions branch from 7a2d086 to 580253e Compare July 29, 2026 12:41

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 29, 2026

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-review Status: Awaiting review from the assignee but also interested parties. labels Jul 29, 2026

JonathanBrouwer mentioned this pull request Jul 29, 2026

Rollup of 7 pull requests #160158

Closed

jhpratt mentioned this pull request Jul 29, 2026

Rollup of 17 pull requests #160168

Closed

jhpratt mentioned this pull request Jul 29, 2026

Rollup of 18 pull requests #160174

Closed

JonathanBrouwer mentioned this pull request Jul 29, 2026

Rollup of 18 pull requests #160182

Closed

jhpratt mentioned this pull request Jul 30, 2026

Rollup of 20 pull requests #160190

Merged

rust-bors Bot merged commit 03de096 into rust-lang:main Jul 30, 2026
13 checks passed

rustbot added this to the 1.99.0 milestone Jul 30, 2026

Uh oh!

Uh oh!

Conversation

LorrensP-2158466 commented Jul 28, 2026 • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

petrochenkov commented Jul 28, 2026

Uh oh!

This comment has been minimized.

This comment has been minimized.

rust-bors Bot commented Jul 28, 2026

Uh oh!

This comment has been minimized.

rust-timer commented Jul 29, 2026

Overall result: ❌ regressions - no action needed

Instruction count

Max RSS (memory usage)

Cycles

Binary size

Uh oh!

LorrensP-2158466 commented Jul 29, 2026

Uh oh!

petrochenkov commented Jul 29, 2026

Uh oh!

Uh oh!

petrochenkov Jul 29, 2026 • edited by rustbot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

LorrensP-2158466 Jul 29, 2026

Choose a reason for hiding this comment

Uh oh!

petrochenkov commented Jul 29, 2026

Uh oh!

rustbot commented Jul 29, 2026

Uh oh!

LorrensP-2158466 commented Jul 29, 2026

Uh oh!

petrochenkov commented Jul 29, 2026

Uh oh!

rust-bors Bot commented Jul 29, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

LorrensP-2158466 commented Jul 28, 2026 •

edited by rustbot

Loading

petrochenkov Jul 29, 2026 •

edited by rustbot

Loading