Use a reduced recursion limit in the MIR inliner's cycle breaker
This probably papers over https://github.com/rust-lang/rust/issues/128887, but primarily I'm opening this PR because multiple compiler people have thought about making this change which probably means it's a good idea.
r? compiler-errors
Add `needs-unwind` compiletest directive to `libtest-thread-limit` and replace some `Path` with `path` in `run-make`
Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).
This PR does two things:
1. Add this to `libtest-thread-limit` ([Why?](https://github.com/rust-lang/rust/pull/128507#issuecomment-2315158014))
```
//@ needs-unwind
// Reason: this should be ignored in cg_clif (Cranelift) CI and anywhere
// else that uses panic=abort.
```
2. Use `path` instead of `Path` to simplify multiple run-make tests.
debug-fmt-detail option
I'd like to propose a new option that makes `#[derive(Debug)]` generate no-op implementations that don't print anything, and makes `{:?}` in format strings a no-op.
There are a couple of motivations for this:
1. A more thorough stripping of debug symbols. Binaries stripped of debug symbols still retain some of them through `Debug` implementations. It's hard to avoid that without compiler's help, because debug formatting can be used in many places, including dependencies, and their loggers, asserts, panics, etc.
* In my testing it gives about 2% binary size reduction on top of all other binary-minimizing best practices (including `panic_immediate_abort`). There are targets like Web WASM or embedded where users pay attention to binary sizes.
* Users distributing closed-source binaries may not want to "leak" any symbol names as a matter of principle.
2. Adds ability to test whether code depends on specifics of the `Debug` format implementation in unwise ways (e.g. trying to get data unavailable via public interface, or using it as a serialization format). Because current Rust's debug implementation doesn't change, there's a risk of it becoming a fragile de-facto API that [won't be possible to change in the future](https://www.hyrumslaw.com/). An option that "breaks" it can act as a [grease](https://www.rfc-editor.org/rfc/rfc8701.html).
This implementation is a `-Z fmt-debug=opt` flag that takes:
* `full` — the default, current state.
* `none` — makes derived `Debug` and `{:?}` no-ops. Explicit `impl Debug for T` implementations are left unharmed, but `{:?}` format won't use them, so they may get dead-code eliminated if they aren't invoked directly.
* `shallow` — makes derived `Debug` print only the type's name, without recursing into fields. Fieldless enums print their variant names. `{:?}` works.
The `shallow` option is a compromise between minimizing the `Debug` code, and compatibility. There are popular proc-macro crates that use `Debug::fmt` as a way to convert enum values into their Rust source code.
There's a corresponding `cfg` flag: `#[cfg(fmt_debug = "none")]` that can be used in user code to react to this setting to minimize custom `Debug` implementations or remove unnecessary formatting helper functions.
* Use a lookup table for 8-bit integers and the Karatsuba square root
algorithm for larger integers.
* Include optimization hints that give the compiler the exact numeric
range of results.
* Choose test inputs more thoroughly and systematically.
* Check that `isqrt` and `checked_isqrt` have equivalent results for
signed types, either equivalent numerically or equivalent as a panic
and a `None`.
* Check that `isqrt` has numerically-equivalent results for unsigned
types and their `NonZero` counterparts.
* Reuse `ilog10` benchmarks, plus benchmarks that use a uniform
distribution.
Rollup of 14 pull requests
Successful merges:
- #128192 (rustc_target: Add various aarch64 features)
- #129170 (Add an ability to convert between `Span` and `visit::Location`)
- #129343 (Emit specific message for time<=0.3.35)
- #129378 (Clean up cfg-gating of ProcessPrng extern)
- #129401 (Partially stabilize `feature(new_uninit)`)
- #129467 (derive(SmartPointer): assume pointee from the single generic and better error messages)
- #129494 (format code in tests/ui/threads-sendsync)
- #129617 (Update books)
- #129673 (Add fmt::Debug to sync::Weak<T, A>)
- #129683 (copysign with sign being a NaN can have non-portable results)
- #129689 (Move `'tcx` lifetime off of impl and onto methods for `CrateMetadataRef`)
- #129695 (Fix path to run clippy on rustdoc)
- #129712 (Correct trusty targets to be tier 3)
- #129715 (Update `compiler_builtins` to `0.1.123`)
r? `@ghost`
`@rustbot` modify labels: rollup
Correct trusty targets to be tier 3
The Trusty targets were added in https://github.com/rust-lang/rust/pull/129490, but in that PR I accidentally marked them as tier 2. This PR corrects the target metadata to mark them as tier 3.
Fix path to run clippy on rustdoc
Took me a while to find out that the path clippy expected was `src/tools/rustdoc` and not `src/librustdoc`. I think it makes more sense this way as most commands rely on source paths.
r? ```@Kobzol```
Move `'tcx` lifetime off of impl and onto methods for `CrateMetadataRef`
Unconstrained type and const variables are not allowed, but unconstrained lifetimes are. This is not very good style, though, and it leads to unnecessary captures of a lifetime in edition 2024 (not that it matters, but it does trigger the edition migration lint).
copysign with sign being a NaN can have non-portable results
Follow-up to https://github.com/rust-lang/rust/pull/129559.
Cc ```@tgross35``` ```@beetrees```
There's no portable variant we can recommend instead here, is there? Something with a semantics like "if `sign` is a NaN, then return `self` unaltered, otherwise return `self` with the sign changed to that of `sign`"?
Add fmt::Debug to sync::Weak<T, A>
Currently, `sync::Weak<T>` implements `Debug`, but `sync::Weak<T, A>` does not. This appears to be an oversight, as `rc::Weak<T, A>` implements `Debug`. (Note: `sync::Weak` is the weak for `Arc`, and `rc::Weak` is the weak for `Rc`.)
This PR adds the Debug trait for `sync::Weak<T, A>`. The issue was initially brought up here: https://github.com/rust-lang/wg-allocators/issues/131
