mgca: Add ConstArg representation for const items
tracking issue: rust-lang/rust#132980fixesrust-lang/rust#131046fixesrust-lang/rust#134641
As part of implementing `min_generic_const_args`, we need to distinguish const items that can be used in the type system, such as in associated const equality projections, from const items containing arbitrary const code, which must be kept out of the type system. Specifically, all "type consts" must be either concrete (no generics) or generic with a trivial expression like `N` or a path to another type const item.
To syntactically distinguish these cases, we require, for now at least, that users annotate all type consts with the `#[type_const]` attribute. Then, we validate that the const's right-hand side is indeed eligible to be a type const and represent it differently in the HIR.
We accomplish this representation using a new `ConstItemRhs` enum in the HIR, and a similar but simpler enum in the AST. When `#[type_const]` is **not** applied to a const (e.g. on stable), we represent const item right-hand sides (rhs's) as HIR bodies, like before. However, when the attribute is applied, we instead lower to a `hir::ConstArg`. This syntactically distinguishes between trivial const args (paths) and arbitrary expressions, which are represented using `AnonConst`s. Then in `generics_of`, we can take advantage of the existing machinery to bar the `AnonConst` rhs's from using parent generics.
Add LLVM realtime sanitizer
This is a new attempt at adding the [LLVM real-time sanitizer](https://clang.llvm.org/docs/RealtimeSanitizer.html) to rust.
Previously this was attempted in https://github.com/rust-lang/rfcs/pull/3766.
Since then the `sanitize` attribute was introduced in https://github.com/rust-lang/rust/pull/142681 and it is a lot more flexible than the old `no_santize` attribute. This allows adding real-time sanitizer without the need for a new attribute, like it was proposed in the RFC. Because i only add a new value to a existing command line flag and to a attribute i don't think an MCP is necessary.
Currently real-time santizer is usable in rust code with the [rtsan-standalone](https://crates.io/crates/rtsan-standalone) crate. This downloads or builds the sanitizer runtime and then links it into the rust binary.
The first commit adds support for more detailed sanitizer information.
The second commit then actually adds real-time sanitizer.
The third adds a warning against using real-time sanitizer with async functions, cloures and blocks because it doesn't behave as expected when used with async functions. I am not sure if this is actually wanted, so i kept it in a seperate commit.
The fourth commit adds the documentation for real-time sanitizer.
This implements a new unstable compiler flag `-Zannotate-moves` that makes
move and copy operations visible in profilers by creating synthetic debug
information. This is achieved with zero runtime cost by manipulating debug
info scopes to make moves/copies appear as calls to `compiler_move<T, SIZE>`
and `compiler_copy<T, SIZE>` marker functions in profiling tools.
This allows developers to identify expensive move/copy operations in their
code using standard profiling tools, without requiring specialized tooling
or runtime instrumentation.
The implementation works at codegen time. When processing MIR operands
(`Operand::Move` and `Operand::Copy`), the codegen creates an `OperandRef`
with an optional `move_annotation` field containing an `Instance` of the
appropriate profiling marker function. When storing the operand,
`store_with_annotation()` wraps the store operation in a synthetic debug
scope that makes it appear inlined from the marker.
Two marker functions (`compiler_move` and `compiler_copy`) are defined
in `library/core/src/profiling.rs`. These are never actually called -
they exist solely as debug info anchors.
Operations are only annotated if the type:
- Meets the size threshold (default: 65 bytes, configurable via
`-Zannotate-moves=SIZE`)
- Has a non-scalar backend representation (scalars use registers,
not memcpy)
This has a very small size impact on object file size. With the default
limit it's well under 0.1%, and even with a very small limit of 8 bytes
it's still ~1.5%. This could be enabled by default.
Stabilize `fmt::from_fn`
Resolvesrust-lang/rust#146705, pending its FCP.
As discussed in that tracking issue and rust-lang/rust#117729, this splits `fmt::from_fn` out from the `debug_closure_helpers` feature.
Implement pin-project in pattern matching for `&pin mut|const T`
This PR implements part of rust-lang/rust#130494. It supports pin-project in pattern matching for `&pin mut|const T`.
~Pin-projection by field access (i.e. `&pin mut|const place.field`) is not fully supported yet since pinned-borrow is not ready (rust-lang/rust#135731).~
CC ``````@traviscross``````
Constify trait aliases
Allow `const trait Foo = Bar + [const] Baz;` trait alias declarations. Their rules are the same as with super traits of const traits. So `[const] Baz` or `const Baz` is only required for `[const] Foo` or `const Foo` bounds respectively.
tracking issue rust-lang/rust#41517 (part of the general trait alias feature gate, but I can split it out into a separate const trait alias feature gate. I just assumed that const traits would stabilize before trait aliases, and we'd want to stabilize trait aliases together with const trait aliases at the same time)
r? ``@compiler-errors`` ``@fee1-dead``
Mark desugared range expression spans with DesugaringKind::RangeExpr
This is a prerequisite to removing `QPath::LangItem` (rust-lang/rust#115178) because otherwise there would be no way to detect a range expression in the HIR.
There are some non-obvious Clippy changes so a Clippy team review would be good.
Clairify docs for `AttributeKind::DocComment`
Makes it clear that this represents `#[doc = "content"]`, but not `#[doc(hidden)]` (or other uses of the `#[doc(...)]` attribute).
r? `@jdonszelmann`
interpret `#[used]` as `#[used(compiler)]` on illumos
helps rust-lang/rust#146169 not be as painful: fixes the illumos regression in rust-lang/rust#140872, but `#[used(linker)]` is still erroneous on illumos generally.
illumos' `ld` does not support a flag like either SHF_GNU_RETAIN or SHF_SUNW_NODISCARD, so there is no way to communicate `#[used(linker)]` for that target. Setting `USED_LINKER` to try results in LLVM setting SHF_SUNW_NODISCARD for Solaris-like targets, which is an unknown section header flag for illumos `ld` and prevents sections from being merged that otherwise would.
As a motivating example, the `inventory` crate produces `#[used]` items to merge into `.init_array`. Because those items have an unknown section header flag they are not merged with the default `.init_array` with `frame_dummy`, and end up never executed.
Downgrading `#[used]` to `#[used(compiler)]` on illumos keeps so-attributed items as preserved as they had been before https://github.com/rust-lang/rust/pull/140872. As was the case before that change, because rustc passes `-z ignore` to illumos `ld`, it's possible that `used` sections are GC'd at link time. https://github.com/rust-lang/rust/issues/146169 describes this unfortunate circumstance.
----
as it turns out, `tests/ui/attributes/used_with_archive.rs` had broken on `x86_64-unknown-illumos`, and this patch fixes it. the trials and tribulations of tier 2 :(
r? ````@Noratrieb```` probably?
illumos' `ld` does not support a flag like either SHF_GNU_RETAIN or
SHF_SUNW_NODISCARD, so there is no way to communicate `#[used(linker)]`
for that target. Setting `USED_LINKER` to try results in LLVM setting
SHF_SUNW_NODISCARD for Solaris-like targets, which is an unknown section
header flag for illumos `ld` and prevents sections from being merged
that otherwise would.
As a motivating example, the `inventory` crate produces
`#[used]` items to merge into `.init_array`. Because those items have an
unknown section header flag they are not merged with the default
`.init_array` with `frame_dummy`, and end up never executed.
Downgrading `#[used]` to `#[used(compiler)]` on illumos keeps
so-attributed items as preserved as they had been before
https://github.com/rust-lang/rust/pull/140872. As was the case before
that change, because rustc passes `-z ignore` to illumos `ld`, it's
possible that `used` sections are GC'd at link time.
https://github.com/rust-lang/rust/issues/146169 describes this
unfortunate circumstance.
Use `Iterator::eq` and (dogfood) `eq_by` in compiler and library
Now that rust-lang/rust#137122 has landed, we can replace stuff that looks like:
```rust
let a: &[T];
let b: &[T];
let eq = a.len() == b.len() && a.iter().zip(b).all(|(a,b)| a == b)
```
with the much simpler `a.iter().eq(b)`, without losing the perf benefit of the different-length-fast-path.
Also dogfooded `Iterator::eq_by` (cc rust-lang/rust#64295 ) while I'm at it.
First commit (4d1b6fad230f8a5ccceccc7562eadc4ea50059da) should be very straightforward to review, second one (049a4606cb3906787aedf508ee8eea09c2bb3b9a) is slightly more creative, but IMHO a nice cleanup.
improve diagnostics for empty attributes
Adds a note about them not having any effect. This was previously done for `feature` attributes but no other attributes. In [converting the `feature` parser](https://github.com/rust-lang/rust/pull/146652) I removed that note. This PR adds it back in and makes it so all attributes benefit from it.
Not blocked on rust-lang/rust#146652, either can merge first
Introduce CoerceShared lang item and trait, and basic Reborrow tests
Part of rust-lang/rust#145612: This introduces the `CoerceShared` trait which is the `Reborrow` equivalent of a `&mut T` -> `&T` coercion. The trait has a `Target` GAT which makes this (currently) unique in the `core/src/marker.rs`; I'm not sure if this can be considered problematic. Maybe this is not the way such things should be done at the marker trait level? Or maybe it is fine.
Improtantly, this PR introduces a battery of basic `Reborrow` and `CoerceShared` tests. These test the very basics of the feature; custom marker types intended to have exclusive semantics (`Custom<'a>(PhantomData<&'a mut ()>)`), custom exclusive reference wrappers, and standard library exclusive reference wrappers (`Pin<&mut T>` and `Option<&mut T>`). None of these of course work since the implementation for `Reborrow` and `CoerceShared` is entirely missing, but this is the first step towards making these work.
Future PRs will introduce more tests, such as "recursive" reborrowing (ie. reborrowing structs that contain multiple reborrowable fields) and checks around the lifetime semantics of reborrowing ie. that a reborrow produces a new type with the same lifetime as the original.
Add an attribute to check the number of lanes in a SIMD vector after monomorphization
Allows std::simd to drop the `LaneCount<N>: SupportedLaneCount` trait and maintain good error messages.
Also, extends rust-lang/rust#145967 by including spans in layout errors for all ADTs.
r? ``@RalfJung``
cc ``@workingjubilee`` ``@programmerjake``
