Unsafe extern blocks

[spastorino]

This implements RFC 3484.

Tracking issue #123743 and RFC rust-lang/rfcs#3484

This is better reviewed commit by commit.

[rustbot]

r? @cjgillot

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[rustbot]

⚠️ Warning ⚠️

• These commits modify submodules.

[spastorino]

⚠️ Warning ⚠️

* These commits modify **submodules**.

Ohh I forgot to mention this. I'd need to land some PRs, at least to stdarch so it doesn't warn for the usages of extern blocks without unsafe.
I was planning to do ![allow(unknown_lints)] + #![allow(missing_unsafe_on_extern)], so this doesn't warn in new versions and doesn't error in old versions for the usage of missing_unsafe_on_extern which is unknown.

[traviscross]

Looks right to me.

[traviscross]

Tested cargo fix on a side project, unsure if we are testing somehow in the compiler the machine-applicable information we return in errors?. Maybe making the compiler output json and checking that the machine-applicable fixes are there?. Or do we do that in cargo?.

Have a look at the run-rustfix header command.

See for example this test.

[spastorino]

Tested cargo fix on a side project, unsure if we are testing somehow in the compiler the machine-applicable information we return in errors?. Maybe making the compiler output json and checking that the machine-applicable fixes are there?. Or do we do that in cargo?.

Have a look at the run-rustfix header command.

See for example this test.

Added this too!.

[oli-obk]

@bors r+

[bors]

📌 Commit 525828d has been approved by oli-obk

It is now in the queue for this repository.

[spastorino]

@bors rollup=never

[bors]

⌛ Testing commit 525828d with merge 2d28b63...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 2d28b63 to master...

[rust-timer]

Finished benchmarking commit (2d28b63): 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)	0.3%	[0.2%, 0.4%]	32
Regressions ❌ (secondary)	0.2%	[0.2%, 0.3%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.2%, 0.4%]	32

Max RSS (memory usage)

Results (primary 0.7%)

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)	4.3%	[4.3%, 4.3%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.9%	[-2.9%, -2.9%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.7%	[-2.9%, 4.3%]	2

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: 672.766s -> 672.761s (-0.00%)
Artifact size: 319.44 MiB -> 319.40 MiB (-0.01%)

[Kobzol]

This adds a new feature, so a small regression is probably to be expected. Marking as triaged.

@rustbot label: +perf-regression-triaged

[spastorino]

This adds a new feature, so a small regression is probably to be expected. Marking as triaged.

@rustbot label: +perf-regression-triaged

👍, anyway there's a pre-existing issue in the way we use ItemKind and convert to ForeignItemKind for the sake of code reuse that this PR made slightly worser and may cause such small perf regression. I have this in my todo list to address.
Basically due to these conversions, we have data in ItemKind that we shouldn't.