Rollup of 4 pull requests

[matthiaskrgr]

Successful merges:

• Replace -Z default-hidden-visibility with -Z default-visibility #130005 (Replace -Z default-hidden-visibility with -Z default-visibility)
• ptr::add/sub: do not claim equivalence with offset(c as isize) #130229 (ptr::add/sub: do not claim equivalence with offset(c as isize))
• Update Unicode escapes in /library/core/src/char/methods.rs #130773 (Update Unicode escapes in /library/core/src/char/methods.rs)
• rustdoc: lists items that contain multiple paragraphs are more clear #130933 (rustdoc: lists items that contain multiple paragraphs are more clear)

r? @ghost
@rustbot modify labels: rollup

Create a similar rollup

[matthiaskrgr]

@bors r+ rollup=never p=4

[bors]

📌 Commit bd5ee83 has been approved by matthiaskrgr

It is now in the queue for this repository.

[bors]

⌛ Testing commit bd5ee83 with merge 06bb836...

[bors]

☀️ Test successful - checks-actions
Approved by: matthiaskrgr
Pushing 06bb836 to master...

[rust-timer]

📌 Perf builds for each rolled up PR:

PR#	Message	Perf Build Sha
#130005	Replace -Z default-hidden-visibility with -Z default-visibi…	b6a6fdcb9b739b8ec00d7d37f46b79c27b5cd636 (link)
#130229	ptr::add/sub: do not claim equivalence with `offset(c as is…	c1cd965f24b4e7a9ef6e13428ddd9cd05aa426ce (link)
#130773	Update Unicode escapes in `/library/core/src/char/methods.r…	c050f8588d5d134f88bdcf79066cb7348bac4e04 (link)
#130933	rustdoc: lists items that contain multiple paragraphs are m…	9b2daa699cf8b6458868bcf41392282107254226 (link)

previous master: c817d5dc20

In the case of a perf regression, run the following command for each PR you suspect might be the cause: @rust-timer build $SHA

[rust-timer]

Finished benchmarking commit (06bb836): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.2%, 0.2%]	4
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[0.2%, 0.2%]	4

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 771.522s -> 770.255s (-0.16%)
Artifact size: 341.52 MiB -> 341.52 MiB (0.00%)

[rylev]

It seems like #130005 would be the only PR that could possibly have introduced any perf variation here though it's not clear to me why.

@rust-timer build b6a6fdc

[rust-timer]

Finished benchmarking commit (b6a6fdc): comparison URL.

Overall result: ❌ regressions - please read the text below

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.1%, 0.2%]	5
Regressions ❌ (secondary)	0.2%	[0.2%, 0.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[0.1%, 0.2%]	5

Max RSS (memory usage)

Results (primary 4.5%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	4.5%	[4.5%, 4.5%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	4.5%	[4.5%, 4.5%]	1

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 771.522s -> 769.405s (-0.27%)
Artifact size: 341.52 MiB -> 341.53 MiB (0.00%)

[lqd]

though it's not clear to me why

@rylev I believe it's because the PR introduced new unconditional query calls to compute the symbol visibility (even though it will still return the same default as before, until the default is switched to "protected" in the future). The big reachable_non_generics query in particular.

That is, we could gain the perf back, and delay this computation until that change is needed, most likely when lld is used on stable by default, so not right around the corner.

[rylev]

cc @davidlattimore @Urgau (author and reviewer of #130005) for visibility ^^

[Urgau]

Yeah, we may want to re-add the fast path for !did.is_local():

rust/compiler/rustc_monomorphize/src/partitioning.rs

Lines 916 to 920 in 0999b01

	// Things with export level C don't get instantiated in
	// downstream crates.
	if !id.is_local() {
	return Visibility::Hidden;
	}

[lqd]

The query will be more costly than the is_local() check.

[Urgau]

Oh, yeah you're right, when the default visibility wasn't changed we just returned Default and did nothing else.

rust/compiler/rustc_monomorphize/src/partitioning.rs

Lines 906 to 909 in 0999b01

	fn default_visibility(tcx: TyCtxt<'_>, id: DefId, is_generic: bool) -> Visibility {
	if !tcx.sess.default_hidden_visibility() {
	return Visibility::Default;
	}

I completely overlook that.