Experimental feature postfix match
This has a basic experimental implementation for the RFC postfix match (rust-lang/rfcs#3295, #121618). [Liaison is](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Postfix.20Match.20Liaison/near/423301844) ```@scottmcm``` with the lang team's [experimental feature gate process](https://github.com/rust-lang/lang-team/blob/master/src/how_to/experiment.md).
This feature has had an RFC for a while, and there has been discussion on it for a while. It would probably be valuable to see it out in the field rather than continue discussing it. This feature also allows to see how popular postfix expressions like this are for the postfix macros RFC, as those will take more time to implement.
It is entirely implemented in the parser, so it should be relatively easy to remove if needed.
This PR is split in to 5 commits to ease review.
1. The implementation of the feature & gating.
2. Add a MatchKind field, fix uses, fix pretty.
3. Basic rustfmt impl, as rustfmt crashes upon seeing this syntax without a fix.
4. Add new MatchSource to HIR for Clippy & other HIR consumers
`f16` and `f128` step 3: compiler support & feature gate
Continuation of https://github.com/rust-lang/rust/pull/121841, another portion of https://github.com/rust-lang/rust/pull/114607
This PR exposes the new types to the world and adds a feature gate. Marking this as a draft because I need some feedback on where I did the feature gate check. It also does not yet catch type via suffixed literals (so the feature gate test will fail, probably some others too because I haven't belssed).
If there is a better place to check all types after resolution, I can do that. If not, I figure maybe I can add a second gate location in AST when it checks numeric suffixes.
Unfortunately I still don't think there is much testing to be done for correctness (codegen tests or parsed value checks) until we have basic library support. I think that will be the next step.
Tracking issue: https://github.com/rust-lang/rust/issues/116909
r? `@compiler-errors`
cc `@Nilstrieb`
`@rustbot` label +F-f16_and_f128
coverage: Initial support for branch coverage instrumentation
(This is a review-ready version of the changes that were drafted in #118305.)
This PR adds support for branch coverage instrumentation, gated behind the unstable flag value `-Zcoverage-options=branch`. (Coverage instrumentation must also be enabled with `-Cinstrument-coverage`.)
During THIR-to-MIR lowering (MIR building), if branch coverage is enabled, we collect additional information about branch conditions and their corresponding then/else blocks. We inject special marker statements into those blocks, so that the `InstrumentCoverage` MIR pass can reliably identify them even after the initially-built MIR has been simplified and renumbered.
The rest of the changes are mostly just plumbing needed to gather up the information that was collected during MIR building, and include it in the coverage metadata that we embed in the final binary.
Note that `llvm-cov show` doesn't print branch coverage information in its source views by default; that needs to be explicitly enabled with `--show-branches=count` or similar.
---
The current implementation doesn't have any support for instrumenting `if let` or let-chains. I think it's still useful without that, and adding it would be non-trivial, so I'm happy to leave that for future work.
Includes related tests and documentation pages.
Michael Goulet: Don't issue feature error in resolver for f16/f128
unless finalize
Co-authored-by: Michael Goulet <michael@errs.io>
rustdoc-search: search types by higher-order functions
This feature extends rustdoc with syntax and search index information for searching function pointers and closures (Higher-Order Functions, or HOF). Part of https://github.com/rust-lang/rust/issues/60485
This PR adds two syntaxes: a high-level one for finding any kind of HOF, and a direct implementation of the parenthesized path syntax that Rust itself uses.
## Preview pages
| Query | Results |
|-------|---------|
| [`option<T>, (fnonce (T) -> bool) -> option<T>`][optionfilter] | `Option::filter` |
| [`option<T>, (T -> bool) -> option<T>`][optionfilter2] | `Option::filter` |
Updated chapter of the book: https://notriddle.com/rustdoc-html-demo-9/search-hof/rustdoc/read-documentation/search.html
[optionfilter]: https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=option<T>%2C+(fnonce+(T)+->+bool)+->+option<T>&filter-crate=std
[optionfilter2]: https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=option<T>%2C+(T+->+bool)+->+option<T>&filter-crate=std
## Motivation
When type-based search was first landed, it was directly [described as incomplete][a comment].
[a comment]: https://github.com/rust-lang/rust/pull/23289#issuecomment-79437386
Filling out the missing functionality is going to mean adding support for more of Rust's [type expression] syntax, such as references, raw pointers, function pointers, and closures. This PR adds function pointers and closures.
[type expression]: https://doc.rust-lang.org/reference/types.html#type-expressions
There's been demand for something "like Hoogle, but for Rust" expressed a few times [1](https://www.reddit.com/r/rust/comments/y8sbid/is_there_a_website_like_haskells_hoogle_for_rust/) [2](https://users.rust-lang.org/t/rust-equivalent-of-haskells-hoogle/102280) [3](https://internals.rust-lang.org/t/std-library-inclusion-policy/6852/2) [4](https://discord.com/channels/442252698964721669/448238009733742612/1109502307495858216). Some of them just don't realize what functionality already exists ([`Duration -> u64`](https://doc.rust-lang.org/nightly/std/?search=duration%20-%3E%20u64) already works), but a lot of them specifically want to search for higher-order functions like option combinators.
## Guide-level explanation (from the Rustdoc book)
To search for a function that accepts a function as a parameter, like `Iterator::all`, wrap the nested signature in parenthesis, as in [`Iterator<T>, (T -> bool) -> bool`][iterator-all]. You can also search for a specific closure trait, such as `Iterator<T>, (FnMut(T) -> bool) -> bool`, but you need to know which one you want.
[iterator-all]: https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=Iterator<T>%2C+(T+->+bool)+->+bool&filter-crate=std
## Reference-level description (also from the Rustdoc book)
### Primitives with Special Syntax
<table>
<thead>
<tr>
<th>Shorthand</th>
<th>Explicit names</th>
</tr>
</thead>
<tbody>
<tr><td colspan="2">Before this PR</td></tr>
<tr>
<td><code>[]</code></td>
<td><code>primitive:slice</code> and/or <code>primitive:array</code></td>
</tr>
<tr>
<td><code>[T]</code></td>
<td><code>primitive:slice<T></code> and/or <code>primitive:array<T></code></td>
</tr>
<tr>
<td><code>!</code></td>
<td><code>primitive:never</code></td>
</tr>
<tr>
<td><code>()</code></td>
<td><code>primitive:unit</code> and/or <code>primitive:tuple</code></td>
</tr>
<tr>
<td><code>(T)</code></td>
<td><code>T</code></td>
</tr>
<tr>
<td><code>(T,)</code></td>
<td><code>primitive:tuple<T></code></td>
</tr>
<tr><td colspan="2">After this PR</td></tr>
<tr>
<td><code>(T, U -> V, W)</code></td>
<td><code>fn(T, U) -> (V, W)</code>, Fn, FnMut, and FnOnce</td>
</tr>
</tbody>
</table>
The `->` operator has lower precedence than comma. If it's not wrapped in brackets, it delimits the return value for the function being searched for. To search for functions that take functions as parameters, use parenthesis.
### Search query grammar
```ebnf
ident = *(ALPHA / DIGIT / "_")
path = ident *(DOUBLE-COLON ident) [BANG]
slice-like = OPEN-SQUARE-BRACKET [ nonempty-arg-list ] CLOSE-SQUARE-BRACKET
tuple-like = OPEN-PAREN [ nonempty-arg-list ] CLOSE-PAREN
arg = [type-filter *WS COLON *WS] (path [generics] / slice-like / tuple-like)
type-sep = COMMA/WS *(COMMA/WS)
nonempty-arg-list = *(type-sep) arg *(type-sep arg) *(type-sep) [ return-args ]
generic-arg-list = *(type-sep) arg [ EQUAL arg ] *(type-sep arg [ EQUAL arg ]) *(type-sep)
normal-generics = OPEN-ANGLE-BRACKET [ generic-arg-list ] *(type-sep)
CLOSE-ANGLE-BRACKET
fn-like-generics = OPEN-PAREN [ nonempty-arg-list ] CLOSE-PAREN [ RETURN-ARROW arg ]
generics = normal-generics / fn-like-generics
return-args = RETURN-ARROW *(type-sep) nonempty-arg-list
exact-search = [type-filter *WS COLON] [ RETURN-ARROW ] *WS QUOTE ident QUOTE [ generics ]
type-search = [ nonempty-arg-list ]
query = *WS (exact-search / type-search) *WS
; unchanged parts of the grammar, like the full list of type filters, are omitted
```
## Future direction
### The remaining type expression grammar
As described in https://github.com/rust-lang/rust/pull/118194, this is another step in the type expression grammar: BareFunction, and the function-like mode of TypePath, are now supported.
* RawPointerType and ReferenceType actually are a priority.
* ImplTraitType and TraitObjectType (and ImplTraitTypeOneBound and TraitObjectTypeOneBound) aren't as much of a priority, since they desugar pretty easily.
### Search subtyping and traits
This is the other major factor that makes it less useful than it should be.
* `iterator<result<t>> -> result<t>` doesn't find `Result::from_iter`. You have to search [`intoiterator<result<t>> -> result<t>`](https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=intoiterator%3Cresult%3Ct%3E%3E%20-%3E%20result%3Ct%3E&filter-crate=std). Nobody's going to search for IntoIterator unless they basically already know about it and don't need the search engine anyway.
* Iterator combinators are usually structs that happen to implement Iterator, like `std::iter::Map`.
To solve these cases, it needs to look at trait implementations, knowing that Iterator is a "subtype of" IntoIterator, and Map is a "subtype of" Iterator, so `iterator -> result` is a subtype of `intoiterator -> result` and `iterator<t>, (t -> u) -> iterator<u>` is a subtype of [`iterator<t>, (t -> u) -> map<t -> u>`](https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=iterator%3Ct%3E%2C%20(t%20-%3E%20u)%20-%3E%20map%3Ct%20-%3E%20u%3E&filter-crate=std).
coverage: Remove or migrate all unstable values of `-Cinstrument-coverage`
(This PR was substantially overhauled from its original version, which migrated all of the existing unstable values intact.)
This PR takes the three nightly-only values that are currently accepted by `-Cinstrument-coverage`, completely removes two of them (`except-unused-functions` and `except-unused-generics`), and migrates the third (`branch`) over to a newly-introduced unstable flag `-Zcoverage-options`.
I have a few motivations for wanting to do this:
- It's unclear whether anyone actually uses the `except-unused-*` values, so this serves as an opportunity to either remove them, or prompt existing users to object to their removal.
- After #117199, the stable values of `-Cinstrument-coverage` treat it as a boolean-valued flag, so having nightly-only extra values feels out-of-place.
- Nightly-only values also require extra ad-hoc code to make sure they aren't accidentally exposed to stable users.
- The new system allows multiple different settings to be toggled independently, which isn't possible in the current single-value system.
- The new system makes it easier to introduce new behaviour behind an unstable toggle, and then gather nightly-user feedback before possibly making it the default behaviour for all users.
- The new system also gives us a convenient place to put relatively-narrow options that won't ever be the default, but that nightly users might still want access to.
- It's likely that we will eventually want to give stable users more fine-grained control over coverage instrumentation. The new flag serves as a prototype of what that stable UI might eventually look like.
The `branch` option is a placeholder that currently does nothing. It will be used by #122322 to opt into branch coverage instrumentation.
---
I see `-Zcoverage-options` as something that will exist more-or-less indefinitely, though individual sub-options might come and go as appropriate. I think there will always be some demand for nightly-only toggles, so I don't see `-Zcoverage-options` itself ever being stable, though we might eventually stabilize something similar to it.
This new nightly-only flag can be used to toggle fine-grained flags that
control the details of coverage instrumentation.
Currently the only supported flag value is `branch` (or `no-branch`), which is
a placeholder for upcoming support for branch coverage. Other flag values can
be added in the future, to prototype proposed new behaviour, or to enable
special non-default behaviour.
Rename `wasm32-wasi-preview1-threads` to `wasm32-wasip1-threads`
This commit renames the current `wasm32-wasi-preview1-threads` target to `wasm32-wasip1-threads`. The need for this rename is a bit unfortunate as the previous name was chosen in an attempt to be future-compatible with other WASI targets. Originally this target was proposed to be `wasm32-wasi-threads`, and that's what was originally implemented in wasi-sdk as well. After discussion though and with the plans for the upcoming component-model target (now named `wasm32-wasip2`) the "preview1" naming was chosen for the threads-based target. The WASI subgroup later decided that it was time to drop the "preview" terminology and recommends "pX" instead, hence previous PRs to add `wasm32-wasip2` and rename `wasm32-wasi` to `wasm32-wasip1`.
So, with all that history, the "proper name" for this target is different than its current name, so one way or another a rename is required. This PR proposes renaming this target cold-turkey, unlike `wasm32-wasi` which is having a long transition period to change its name. The threads-based target is predicted to see only a fraction of the traffic of `wasm32-wasi` due to the unstable nature of the WASI threads proposal itself.
While I was here I updated the in-tree documentation in the target spec file itself as most of the documentation was copied from the original WASI target and wasn't as applicable to this target.
Also, as an aside, I can at least try to apologize for all the naming confusion here, but this is hopefully the last WASI-related rename.
This is implemented, in addition to the ML-style one,
because Rust does it. If we don't, we'll never hear the end of it.
This commit also refactors some duplicate parts of the parser
into a dedicated function.
Option::map, for example, looks like this:
option<t>, (t -> u) -> option<u>
This syntax searches all of the HOFs in Rust: traits Fn, FnOnce,
and FnMut, and bare fn primitives.
This commit renames the current `wasm32-wasi-preview1-threads` target to
`wasm32-wasip1-threads`. The need for this rename is a bit unfortunate
as the previous name was chosen in an attempt to be future-compatible
with other WASI targets. Originally this target was proposed to be
`wasm32-wasi-threads`, and that's what was originally implemented in
wasi-sdk as well. After discussion though and with the plans for the
upcoming component-model target (now named `wasm32-wasip2`) the
"preview1" naming was chosen for the threads-based target. The WASI
subgroup later decided that it was time to drop the "preview"
terminology and recommends "pX" instead, hence previous PRs to add
`wasm32-wasip2` and rename `wasm32-wasi` to `wasm32-wasip1`.
So, with all that history, the "proper name" for this target is
different than its current name, so one way or another a rename is
required. This PR proposes renaming this target cold-turkey, unlike
`wasm32-wasi` which is having a long transition period to change its
name. The threads-based target is predicted to see only a fraction of
the traffic of `wasm32-wasi` due to the unstable nature of the WASI
threads proposal itself.
While I was here I updated the in-tree documentation in the target spec
file itself as most of the documentation was copied from the original
WASI target and wasn't as applicable to this target.
Also, as an aside, I can at least try to apologize for all the naming
confusion here, but this is hopefully the last WASI-related rename.
Add asm goto support to `asm!`
Tracking issue: #119364
This PR implements asm-goto support, using the syntax described in "future possibilities" section of [RFC2873](https://rust-lang.github.io/rfcs/2873-inline-asm.html#asm-goto).
Currently I have only implemented the `label` part, not the `fallthrough` part (i.e. fallthrough is implicit). This doesn't reduce the expressive though, since you can use label-break to get arbitrary control flow or simply set a value and rely on jump threading optimisation to get the desired control flow. I can add that later if deemed necessary.
r? ``@Amanieu``
cc ``@ojeda``
Add arm64ec-pc-windows-msvc target
Introduces the `arm64ec-pc-windows-msvc` target for building Arm64EC ("Emulation Compatible") binaries for Windows.
For more information about Arm64EC see <https://learn.microsoft.com/en-us/windows/arm/arm64ec>.
## Tier 3 policy:
> A tier 3 target must have a designated developer or developers (the "target maintainers") on record to be CCed when issues arise regarding the target. (The mechanism to track and CC such developers may evolve over time.)
I will be the maintainer for this target.
> Targets must use naming consistent with any existing targets; for instance, a target for the same CPU or OS as an existing Rust target should use the same name for that CPU or OS. Targets should normally use the same names and naming conventions as used elsewhere in the broader ecosystem beyond Rust (such as in other toolchains), unless they have a very good reason to diverge. Changing the name of a target can be highly disruptive, especially once the target reaches a higher tier, so getting the name right is important even for a tier 3 target.
Target uses the `arm64ec` architecture to match LLVM and MSVC, and the `-pc-windows-msvc` suffix to indicate that it targets Windows via the MSVC environment.
> Target names should not introduce undue confusion or ambiguity unless absolutely necessary to maintain ecosystem compatibility. For example, if the name of the target makes people extremely likely to form incorrect beliefs about what it targets, the name should be changed or augmented to disambiguate it.
Target name exactly specifies the type of code that will be produced.
> If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo.
Done.
> Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users.
> The target must not introduce license incompatibilities.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Understood.
> The target must not cause the Rust tools or libraries built for any other host (even when supporting cross-compilation to the target) to depend on any new dependency less permissive than the Rust licensing policy. This applies whether the dependency is a Rust crate that would require adding new license exceptions (as specified by the tidy tool in the rust-lang/rust repository), or whether the dependency is a native library or binary. In other words, the introduction of the target must not cause a user installing or running a version of Rust or the Rust tools to be subject to any new license requirements.
> Compiling, linking, and emitting functional binaries, libraries, or other code for the target (whether hosted on the target itself or cross-compiling from another target) must not depend on proprietary (non-FOSS) libraries. Host tools built for the target itself may depend on the ordinary runtime libraries supplied by the platform and commonly used by other applications built for the target, but those libraries must not be required for code generation for the target; cross-compilation to the target must not require such libraries at all. For instance, rustc built for the target may depend on a common proprietary C runtime library or console output library, but must not depend on a proprietary code generation library or code optimization library. Rust's license permits such combinations, but the Rust project has no interest in maintaining such combinations within the scope of Rust itself, even at tier 3.
> "onerous" here is an intentionally subjective term. At a minimum, "onerous" legal/licensing terms include but are not limited to: non-disclosure requirements, non-compete requirements, contributor license agreements (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms, requirements conditional on the employer or employment of any particular Rust developers, revocable terms, any requirements that create liability for the Rust project or its developers or users, or any requirements that adversely affect the livelihood or prospects of the Rust project or its developers or users.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a target, or has any legal or employment requirement (explicit or implicit) that might affect their decisions regarding a target, they must recuse themselves from any approval decisions regarding the target's tier status, though they may otherwise participate in discussions.
> This requirement does not prevent part or all of this policy from being cited in an explicit contract or work agreement (e.g. to implement or maintain support for a target). This requirement exists to ensure that a developer or team responsible for reviewing and approving a target does not face any legal threats or obligations that would prevent them from freely exercising their judgment in such approval, even if such judgment involves subjective matters or goes beyond the letter of these requirements.
Understood, I am not a member of the Rust team.
> Tier 3 targets should attempt to implement as much of the standard libraries as possible and appropriate (core for most targets, alloc for targets that can support dynamic memory allocation, std for targets with an operating system or equivalent layer of system-provided functionality), but may leave some code unimplemented (either unavailable or stubbed out as appropriate), whether because the target makes it impossible to implement or challenging to implement. The authors of pull requests are not obligated to avoid calling any portions of the standard library on the basis of a tier 3 target not implementing those portions.
Both `core` and `alloc` are supported.
Support for `std` depends on making changes to the standard library, `stdarch` and `backtrace` which cannot be done yet as they require fixes coming in LLVM 18.
> The target must provide documentation for the Rust community explaining how to build for the target, using cross-compilation if possible. If the target supports running binaries, or running tests (even if they do not pass), the documentation must explain how to run such binaries or tests for the target, using emulation if possible or dedicated hardware if necessary.
Documentation is provided in src/doc/rustc/src/platform-support/arm64ec-pc-windows-msvc.md
> Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the community, to maintain the target. In particular, do not post comments (automated or manual) on a PR that derail or suggest a block on the PR based on a tier 3 target. Do not send automated messages or notifications (via any medium, including via `@)` to a PR author or others involved with a PR regarding a tier 3 target, unless they have opted into such messages.
> Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not considered a violation of this policy, within reason. However, such messages (even on a separate repository) must not generate notifications to anyone involved with a PR who has not requested such notifications.
> Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and must not knowingly break another tier 3 target without approval of either the compiler team or the maintainers of the other tier 3 target.
> In particular, this may come up when working on closely related targets, such as variations of the same architecture with different features. Avoid introducing unconditional uses of features that another variation of the target may not have; use conditional compilation or runtime detection, as appropriate, to let each target run code supported by that target.
Understood.
Add missing background color for top-level rust documentation page and increase contrast by setting text color to black
Fixes#121954.
r? ``@notriddle``
Stabilize the `#[diagnostic]` namespace and `#[diagnostic::on_unimplemented]` attribute
This PR stabilizes the `#[diagnostic]` attribute namespace and a minimal option of the `#[diagnostic::on_unimplemented]` attribute.
The `#[diagnostic]` attribute namespace is meant to provide a home for attributes that allow users to influence error messages emitted by the compiler. The compiler is not guaranteed to use any of this hints, however it should accept any (non-)existing attribute in this namespace and potentially emit lint-warnings for unused attributes and options. This is meant to allow discarding certain attributes/options in the future to allow fundamental changes to the compiler without the need to keep then non-meaningful options working.
The `#[diagnostic::on_unimplemented]` attribute is allowed to appear on a trait definition. This allows crate authors to hint the compiler to emit a specific error message if a certain trait is not implemented. For the `#[diagnostic::on_unimplemented]` attribute the following options are implemented:
* `message` which provides the text for the top level error message
* `label` which provides the text for the label shown inline in the broken code in the error message
* `note` which provides additional notes.
The `note` option can appear several times, which results in several note messages being emitted. If any of the other options appears several times the first occurrence of the relevant option specifies the actually used value. Any other occurrence generates an lint warning. For any other non-existing option a lint-warning is generated.
All three options accept a text as argument. This text is allowed to contain format parameters referring to generic argument or `Self` by name via the `{Self}` or `{NameOfGenericArgument}` syntax. For any non-existing argument a lint warning is generated.
This allows to have a trait definition like:
```rust
#[diagnostic::on_unimplemented(
message = "My Message for `ImportantTrait<{A}>` is not implemented for `{Self}`",
label = "My Label",
note = "Note 1",
note = "Note 2"
)]
trait ImportantTrait<A> {}
```
which then generates for the following code
```rust
fn use_my_trait(_: impl ImportantTrait<i32>) {}
fn main() {
use_my_trait(String::new());
}
```
this error message:
```
error[E0277]: My Message for `ImportantTrait<i32>` is not implemented for `String`
--> src/main.rs:14:18
|
14 | use_my_trait(String::new());
| ------------ ^^^^^^^^^^^^^ My Label
| |
| required by a bound introduced by this call
|
= help: the trait `ImportantTrait<i32>` is not implemented for `String`
= note: Note 1
= note: Note 2
```
[Playground with the unstable feature](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=05133acce8e1d163d481e97631f17536)
Fixes#111996
Introduces the `arm64ec-pc-windows-msvc` target for building Arm64EC ("Emulation Compatible") binaries for Windows.
For more information about Arm64EC see <https://learn.microsoft.com/en-us/windows/arm/arm64ec>.
Tier 3 policy:
> A tier 3 target must have a designated developer or developers (the "target maintainers") on record to be CCed when issues arise regarding the target. (The mechanism to track and CC such developers may evolve over time.)
I will be the maintainer for this target.
> Targets must use naming consistent with any existing targets; for instance, a target for the same CPU or OS as an existing Rust target should use the same name for that CPU or OS. Targets should normally use the same names and naming conventions as used elsewhere in the broader ecosystem beyond Rust (such as in other toolchains), unless they have a very good reason to diverge. Changing the name of a target can be highly disruptive, especially once the target reaches a higher tier, so getting the name right is important even for a tier 3 target.
Target uses the `arm64ec` architecture to match LLVM and MSVC, and the `-pc-windows-msvc` suffix to indicate that it targets Windows via the MSVC environment.
> Target names should not introduce undue confusion or ambiguity unless absolutely necessary to maintain ecosystem compatibility. For example, if the name of the target makes people extremely likely to form incorrect beliefs about what it targets, the name should be changed or augmented to disambiguate it.
Target name exactly specifies the type of code that will be produced.
> If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo.
Done.
> Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users.
> The target must not introduce license incompatibilities.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Understood.
> The target must not cause the Rust tools or libraries built for any other host (even when supporting cross-compilation to the target) to depend on any new dependency less permissive than the Rust licensing policy. This applies whether the dependency is a Rust crate that would require adding new license exceptions (as specified by the tidy tool in the rust-lang/rust repository), or whether the dependency is a native library or binary. In other words, the introduction of the target must not cause a user installing or running a version of Rust or the Rust tools to be subject to any new license requirements.
> Compiling, linking, and emitting functional binaries, libraries, or other code for the target (whether hosted on the target itself or cross-compiling from another target) must not depend on proprietary (non-FOSS) libraries. Host tools built for the target itself may depend on the ordinary runtime libraries supplied by the platform and commonly used by other applications built for the target, but those libraries must not be required for code generation for the target; cross-compilation to the target must not require such libraries at all. For instance, rustc built for the target may depend on a common proprietary C runtime library or console output library, but must not depend on a proprietary code generation library or code optimization library. Rust's license permits such combinations, but the Rust project has no interest in maintaining such combinations within the scope of Rust itself, even at tier 3.
> "onerous" here is an intentionally subjective term. At a minimum, "onerous" legal/licensing terms include but are not limited to: non-disclosure requirements, non-compete requirements, contributor license agreements (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms, requirements conditional on the employer or employment of any particular Rust developers, revocable terms, any requirements that create liability for the Rust project or its developers or users, or any requirements that adversely affect the livelihood or prospects of the Rust project or its developers or users.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a target, or has any legal or employment requirement (explicit or implicit) that might affect their decisions regarding a target, they must recuse themselves from any approval decisions regarding the target's tier status, though they may otherwise participate in discussions.
> This requirement does not prevent part or all of this policy from being cited in an explicit contract or work agreement (e.g. to implement or maintain support for a target). This requirement exists to ensure that a developer or team responsible for reviewing and approving a target does not face any legal threats or obligations that would prevent them from freely exercising their judgment in such approval, even if such judgment involves subjective matters or goes beyond the letter of these requirements.
Understood, I am not a member of the Rust team.
> Tier 3 targets should attempt to implement as much of the standard libraries as possible and appropriate (core for most targets, alloc for targets that can support dynamic memory allocation, std for targets with an operating system or equivalent layer of system-provided functionality), but may leave some code unimplemented (either unavailable or stubbed out as appropriate), whether because the target makes it impossible to implement or challenging to implement. The authors of pull requests are not obligated to avoid calling any portions of the standard library on the basis of a tier 3 target not implementing those portions.
Both `core` and `alloc` are supported.
Support for `std` dependends on making changes to the standard library, `stdarch` and `backtrace` which cannot be done yet as the bootstrapping compiler raises a warning ("unexpected `cfg` condition value") for `target_arch = "arm64ec"`.
> The target must provide documentation for the Rust community explaining how to build for the target, using cross-compilation if possible. If the target supports running binaries, or running tests (even if they do not pass), the documentation must explain how to run such binaries or tests for the target, using emulation if possible or dedicated hardware if necessary.
Documentation is provided in src/doc/rustc/src/platform-support/arm64ec-pc-windows-msvc.md
> Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the community, to maintain the target. In particular, do not post comments (automated or manual) on a PR that derail or suggest a block on the PR based on a tier 3 target. Do not send automated messages or notifications (via any medium, including via @) to a PR author or others involved with a PR regarding a tier 3 target, unless they have opted into such messages.
> Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not considered a violation of this policy, within reason. However, such messages (even on a separate repository) must not generate notifications to anyone involved with a PR who has not requested such notifications.
> Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and must not knowingly break another tier 3 target without approval of either the compiler team or the maintainers of the other tier 3 target.
> In particular, this may come up when working on closely related targets, such as variations of the same architecture with different features. Avoid introducing unconditional uses of features that another variation of the target may not have; use conditional compilation or runtime detection, as appropriate, to let each target run code supported by that target.
Understood.
Add a scheme for moving away from `extern "rust-intrinsic"` entirely
All `rust-intrinsic`s can become free functions now, either with a fallback body, or with a dummy body and an attribute, requiring backends to actually implement the intrinsic.
This PR demonstrates the dummy-body scheme with the `vtable_size` intrinsic.
cc https://github.com/rust-lang/rust/issues/63585
follow-up to #120500
MCP at https://github.com/rust-lang/compiler-team/issues/720
Rollup of 10 pull requests
Successful merges:
- #120976 (constify a couple thread_local statics)
- #121683 (Fix LVI tests after frame pointers are enabled by default)
- #121703 (Add a way to add constructors for `rustc_type_ir` types)
- #121732 (Improve assert_matches! documentation)
- #121928 (Extract an arguments struct for `Builder::then_else_break`)
- #121939 (Small enhancement to description of From trait)
- #121968 (Don't run test_get_os_named_thread on win7)
- #121969 (`ParseSess` cleanups)
- #121977 (Doc: Fix incorrect reference to integer in Atomic{Ptr,Bool}::as_ptr.)
- #121994 (Update platform-support.md with supported musl version)
r? `@ghost`
`@rustbot` modify labels: rollup
Add a new `wasm32-wasip1` target to rustc
This commit adds a new target called `wasm32-wasip1` to rustc. This new target is explained in these two MCPs:
* https://github.com/rust-lang/compiler-team/issues/607
* https://github.com/rust-lang/compiler-team/issues/695
In short, the previous `wasm32-wasi` target is going to be renamed to `wasm32-wasip1` to better live alongside the [new `wasm32-wasip2` target](https://github.com/rust-lang/rust/pull/119616). This new target is added alongside the `wasm32-wasi` target and has the exact same definition as the previous target. This PR is effectively a rename of `wasm32-wasi` to `wasm32-wasip1`. Note, however, that as explained in rust-lang/compiler-team#695 the previous `wasm32-wasi` target is not being removed at this time. This change will reach stable Rust before even a warning about the rename will be printed. At this time this change is just the start where a new target is introduced and users can start migrating if they support only Nightly for example.
