Unsafe extern blocks #124482

spastorino · 2024-04-28T17:07:50Z

This implements RFC 3484.

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

This is better reviewed commit by commit.

rustbot · 2024-04-28T17:07:58Z

rustbot has assigned @cjgillot.
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rustbot · 2024-04-28T17:07:58Z

⚠️ Warning ⚠️

These commits modify submodules.

spastorino · 2024-04-28T17:22:34Z

⚠️ 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.

rust-timer · 2024-06-06T11:39:48Z

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 · 2024-06-11T06:52:54Z

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

@rustbot label: +perf-regression-triaged

spastorino · 2024-06-11T16:03:12Z

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.

…li-obk Unsafe extern blocks This implements RFC 3484. Tracking issue rust-lang#123743 and RFC rust-lang/rfcs#3484 This is better reviewed commit by commit.

Properly gate `safe` keyword in pre-expansion This PR gates `safe` keyword in pre-expansion contexts. Should mitigate the fallout of rust-lang#126755, which is that `safe` is now usable on beta lol. r? `@spastorino` or `@oli-obk` cc rust-lang#124482 tracking rust-lang#123743

Properly gate `safe` keyword in pre-expansion This PR gates `safe` keyword in pre-expansion contexts. Should mitigate the fallout of rust-lang#126755, which is that `safe` is now usable on beta lol. r? ``@spastorino`` or ``@oli-obk`` cc rust-lang#124482 tracking rust-lang#123743

This includes both `ast::StaticItem` and `ast::StaticForeignItem`. `safety` was added to both `ast::StaticItem` and `ast::SaticForeignItem` in rust-lang/rust#124482.

Properly gate `safe` keyword in pre-expansion This PR gates `safe` keyword in pre-expansion contexts. Should mitigate the fallout of rust-lang#126755, which is that `safe` is now usable on beta lol. r? `@spastorino` or `@oli-obk` cc rust-lang#124482 tracking rust-lang#123743

This includes both `ast::StaticItem` and `ast::StaticForeignItem`. `safety` was added to both `ast::StaticItem` and `ast::SaticForeignItem` in rust-lang/rust#124482.

… r=spastorino rustdoc: Add support for `missing_unsafe_on_extern` feature Follow-up of rust-lang#124482. Not sure if the `safe` keyword is supposed to be displayed or not though? For now I didn't add it in the generated doc, only `unsafe` as usual. cc `@spastorino` r? `@fmease`

…li-obk Unsafe extern blocks This implements RFC 3484. Tracking issue rust-lang#123743 and RFC rust-lang/rfcs#3484 This is better reviewed commit by commit.

…rino rustdoc: Add support for `missing_unsafe_on_extern` feature Follow-up of rust-lang/rust#124482. Not sure if the `safe` keyword is supposed to be displayed or not though? For now I didn't add it in the generated doc, only `unsafe` as usual. cc `@spastorino` r? `@fmease`

…-blocks, r=compiler-errors Stabilize unsafe extern blocks (RFC 3484) # Stabilization report ## Summary This is a tracking issue for the RFC 3484: Unsafe Extern Blocks We are stabilizing `#![feature(unsafe_extern_blocks)]`, as described in [Unsafe Extern Blocks RFC 3484](rust-lang/rfcs#3484). This feature makes explicit that declaring an extern block is unsafe. Starting in Rust 2024, all extern blocks must be marked as unsafe. In all editions, items within unsafe extern blocks may be marked as safe to use. RFC: rust-lang/rfcs#3484 Tracking issue: rust-lang#123743 ## What is stabilized ### Summary of stabilization We now need extern blocks to be marked as unsafe and items inside can also have safety modifiers (unsafe or safe), by default items with no modifiers are unsafe to offer easy migration without surprising results. ```rust unsafe extern { // sqrt (from libm) may be called with any `f64` pub safe fn sqrt(x: f64) -> f64; // strlen (from libc) requires a valid pointer, // so we mark it as being an unsafe fn pub unsafe fn strlen(p: *const c_char) -> usize; // this function doesn't say safe or unsafe, so it defaults to unsafe pub fn free(p: *mut core::ffi::c_void); pub safe static IMPORTANT_BYTES: [u8; 256]; pub safe static LINES: SyncUnsafeCell<i32>; } ``` ## Tests The relevant tests are in `tests/ui/rust-2024/unsafe-extern-blocks`. ## History - rust-lang#124482 - rust-lang#124455 - rust-lang#125077 - rust-lang#125522 - rust-lang#126738 - rust-lang#126749 - rust-lang#126755 - rust-lang#126757 - rust-lang#126758 - rust-lang#126756 - rust-lang#126973 - rust-lang#127535 - rust-lang/rustfmt#6204 ## Unresolved questions I am not aware of any unresolved questions.

Rollup merge of rust-lang#127921 - spastorino:stabilize-unsafe-extern-blocks, r=compiler-errors Stabilize unsafe extern blocks (RFC 3484) # Stabilization report ## Summary This is a tracking issue for the RFC 3484: Unsafe Extern Blocks We are stabilizing `#![feature(unsafe_extern_blocks)]`, as described in [Unsafe Extern Blocks RFC 3484](rust-lang/rfcs#3484). This feature makes explicit that declaring an extern block is unsafe. Starting in Rust 2024, all extern blocks must be marked as unsafe. In all editions, items within unsafe extern blocks may be marked as safe to use. RFC: rust-lang/rfcs#3484 Tracking issue: rust-lang#123743 ## What is stabilized ### Summary of stabilization We now need extern blocks to be marked as unsafe and items inside can also have safety modifiers (unsafe or safe), by default items with no modifiers are unsafe to offer easy migration without surprising results. ```rust unsafe extern { // sqrt (from libm) may be called with any `f64` pub safe fn sqrt(x: f64) -> f64; // strlen (from libc) requires a valid pointer, // so we mark it as being an unsafe fn pub unsafe fn strlen(p: *const c_char) -> usize; // this function doesn't say safe or unsafe, so it defaults to unsafe pub fn free(p: *mut core::ffi::c_void); pub safe static IMPORTANT_BYTES: [u8; 256]; pub safe static LINES: SyncUnsafeCell<i32>; } ``` ## Tests The relevant tests are in `tests/ui/rust-2024/unsafe-extern-blocks`. ## History - rust-lang#124482 - rust-lang#124455 - rust-lang#125077 - rust-lang#125522 - rust-lang#126738 - rust-lang#126749 - rust-lang#126755 - rust-lang#126757 - rust-lang#126758 - rust-lang#126756 - rust-lang#126973 - rust-lang#127535 - rust-lang/rustfmt#6204 ## Unresolved questions I am not aware of any unresolved questions.

rustbot assigned cjgillot Apr 28, 2024