Only load the feature list once in the entire resolver

[oli-obk]

I saw that a bunch of code in ast validation and other early logic just had the features query called once and stored the result. Let's see what the resolver does with that.

[oli-obk]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 4063797 (4063797428d2889154a1f321d903212b4a5c8b32)
Base parent: cddcbec (cddcbec198760511240bf0e728193bf4d700acb4)

[rust-timer]

Finished benchmarking commit (4063797): comparison URL.

Overall result: no relevant changes - 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

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

Max RSS (memory usage)

Results (primary -3.0%, secondary 0.4%)

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)	2.5%	[2.1%, 2.9%]	2
Improvements ✅ (primary)	-3.0%	[-3.2%, -2.7%]	2
Improvements ✅ (secondary)	-1.7%	[-1.7%, -1.7%]	2
All ❌✅ (primary)	-3.0%	[-3.2%, -2.7%]	2

Cycles

Results (primary -1.6%, secondary -1.2%)

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)	2.8%	[2.8%, 2.8%]	1
Improvements ✅ (primary)	-1.6%	[-1.9%, -1.4%]	2
Improvements ✅ (secondary)	-5.2%	[-5.2%, -5.2%]	1
All ❌✅ (primary)	-1.6%	[-1.9%, -1.4%]	2

Binary size

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

Bootstrap: 505.379s -> 504.697s (-0.13%)
Artifact size: 353.06 MiB -> 353.50 MiB (0.12%)

[petrochenkov]

Suggested change

	pub features: &'tcx Features,
	features: &'tcx Features,

Nothing else in Resolver is public, rustc_interface can probably survive calling tcx.features() one more time.

View changes since the review

[oli-obk]

yea 😅 that was a bit overkill

[petrochenkov]

r=me with #158263 (comment) addressed.
@rustbot author

[rustbot]

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

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[oli-obk]

@bors r=petrochenkov rollup

[rust-bors]

📌 Commit bd73fb8 has been approved by petrochenkov

It is now in the queue for this repository.