This commit adds the headers for the top level documentation to
rustdoc's existing table of contents, along with associated items.

It only show two levels of headers. Going further would require the
sidebar to be wider, and that seems unnecessary (the crates that
have manually-built TOCs usually don't need deeply nested headers).

The main `arbitrary_self_types` feature gate will shortly be reused for
a new version of arbitrary self types which we are amending per [this
RFC](https://github.com/rust-lang/rfcs/blob/master/text/3519-arbitrary-self-types-v2.md).
The main amendments are:

* _do_ support `self` types which can't safely implement `Deref`
* do _not_ support generic `self` types
* do _not_ support raw pointers as `self` types.

This PR relates to the last of those bullet points: this strips pointer
support from the current `arbitrary_self_types` feature.
We expect this to cause some amount of breakage for crates using this
unstable feature to allow raw pointer self types. If that's the case, we
want to know about it, and we want crate authors to know of the upcoming
changes.

For now, this can be resolved by adding the new
`arbitrary_self_types_pointers` feature to such crates. If we determine
that use of raw pointers as self types is common, then we may maintain
that as an unstable feature even if we come to stabilize the rest of the
`arbitrary_self_types` support in future. If we don't hear that this PR
is causing breakage, then perhaps we don't need it at all, even behind
an unstable feature gate.

[Tracking issue](rust-lang#44874)

This is [step 4 of the plan outlined here](rust-lang#44874 (comment))

fixes rust-lang#129528

Signed-off-by: Miguel Ojeda <[email protected]>

Apparently tools like `rustfmt` require it in order to find the right
`librustc_driver.so` without extra tweaks.

Signed-off-by: Miguel Ojeda <[email protected]>

Signed-off-by: Miguel Ojeda <[email protected]>

This change will also remove the current warnings in the build due to
`rustfmt` not being available (for `bindgen` output):

    error: 'rustfmt' is not installed for the custom toolchain 'local'.
    note: this is a custom toolchain, which cannot use `rustup component add`
    help: if you built this toolchain from source, and used `rustup toolchain link`, then you may be able to build the component with `x.py`
    Failed to run rustfmt: Internal rustfmt error (non-fatal, continuing)

Signed-off-by: Miguel Ojeda <[email protected]>

This particular target does not expand into much code, so it is a good
first candidate to see if we could keep this in the CI.

Signed-off-by: Miguel Ojeda <[email protected]>

It will make it easier to add more in the future.

Signed-off-by: Miguel Ojeda <[email protected]>

…layout

Additionally teach compiletest to ignore tests that rely on deterministic layout.
Tests themselves aren't built with randomization but they can still observe
slight changes in std or rustc

…l struct sizes

Per the `waker_getters` FCP:
rust-lang#96992 (comment)

Per the `waker_getters` FCP:
rust-lang#96992 (comment)

Docs largely copied from `RawWaker::new`.

Signed-off-by: onur-ozkan <[email protected]>

Signed-off-by: onur-ozkan <[email protected]>

…-Simulacrum

enable -Zrandomize-layout in debug CI builds

This builds rustc/libs/tools with `-Zrandomize-layout` on *-debug CI runners.

Only a handful of tests and asserts break with that enabled, which is promising. One test was fixable, the rest is dealt with by disabling them through new cargo features or compiletest directives.

The config.toml flag `rust.randomize-layout` defaults to false, so it has to be explicitly enabled for now.

rustdoc: add header map to the table of contents

## Summary

Add header sections to the sidebar TOC.

### Preview

![image](https://github.com/user-attachments/assets/eae4df02-86aa-4df4-8c61-a95685cd8829)

* http://notriddle.com/rustdoc-html-demo-9/toc/rust/std/index.html
* http://notriddle.com/rustdoc-html-demo-9/toc/rust-derive-builder/derive_builder/index.html

## Motivation

Some pages are very wordy, like these.

| crate | word count |
|--|--|
| [std::option](https://doc.rust-lang.org/stable/std/option/index.html) | 2,138
| [derive_builder](https://docs.rs/derive_builder/0.13.0/derive_builder/index.html) | 2,403
| [tracing](https://docs.rs/tracing/0.1.40/tracing/index.html) | 3,912
| [regex](https://docs.rs/regex/1.10.3/regex/index.html) | 8,412

This kind of very long document is more navigable with a table of contents, like Wikipedia's or the one [GitHub recently added](https://github.blog/changelog/2021-04-13-table-of-contents-support-in-markdown-files/) for READMEs.

In fact, the use case is so compelling, that it's been requested multiple times and implemented in an extension:

* rust-lang#80858
* rust-lang#28056
* rust-lang#14475
* https://rust.extension.sh/#show-table-of-content

(Some of these issues ask for more than this, so don’t close them.)

It's also been implemented by hand in some crates, because the author really thought it was needed. Protip: for a more exhaustive list, run [`site:docs.rs table of contents`](https://duckduckgo.com/?t=ffab&q=site%3Adocs.rs+table+of+contents&ia=web), though some of them are false positives.

* https://docs.rs/figment/0.10.14/figment/index.html#table-of-contents
* https://docs.rs/csv/1.3.0/csv/tutorial/index.html#table-of-contents
* https://docs.rs/axum/0.7.4/axum/response/index.html#table-of-contents
* https://docs.rs/regex-automata/0.4.5/regex_automata/index.html#table-of-contents

Unfortunately for these hand-built ToCs, because they're just part of the docs, there's no consistent way to turn them off if the reader doesn't want them. It's also more complicated to ensure they stay in sync with the docs they're supposed to describe, and they don't stay with you when you scroll like Wikipedia's [does now](https://uxdesign.cc/design-notes-on-the-2023-wikipedia-redesign-d6573b9af28d).

## Guide-level explanation

When writing docs for a top-level item, the first and second level of headers will be shown in an outline in the sidebar. In this context, "top level" means "not associated".

This means, if you're writing very long guides or explanations, and you want it to have a table of contents in the sidebar for its headings, the ideal place to attach it is usually the *module* or *crate*, because this page has fewer other things on it (and is the ideal place to describe "cross-cutting concerns" for its child items).

If you're reading documentation, and want to get rid of the table of contents, open the ![image](https://github.com/rust-lang/rust/assets/1593513/2ad82466-5fe3-4684-b1c2-6be4c99a8666) Settings panel and checkmark "Hide table of contents."

## Reference-level explanation

Top-level items have an outline generated. This works for potentially-malformed header trees by pairing a header with the nearest header with a higher level. For example:

```markdown
## A
# B
# C
## D
## E
```

A, B, and C are all siblings, and D and E are children of C.

Rustdoc only presents two layers of tree, but it tracks up to the full depth of 6 while preparing it.

That means that these two doc comment both generate the same outline:

```rust
/// # First
/// ## Second
struct One;
/// ## First
/// ### Second
struct Two;
```

## Drawbacks

The biggest drawback is adding more stuff to the sidebar.

My crawl through docs.rs shows this to, surprisingly, be less of a problem than I thought. The manually-built tables of contents, and the pages with dozens of headers, usually seem to be modules or crates, not types (where extreme scrolling would become a problem, since they already have methods to deal with).

The best example of a type with many headers is [vec::Vec](https://doc.rust-lang.org/1.75.0/std/vec/struct.Vec.html), which still only has five headers, not dozens like [axum::extract](https://docs.rs/axum/0.7.4/axum/extract/index.html).

## Rationale and alternatives

### Why in the existing sidebar?

The method links and the top-doc header links have more in common with each other than either of them do with the "In [parent module]" links, and should go together.

### Why limited to two levels?

The sidebar is pretty narrow, and I don't want too much space used by indentation. Making the sidebar wider, while it has some upsides, also takes up more space on middling-sized screens or tiled WMs.

### Why not line wrap?

That behaves strangely when resizing.

## Prior art

### Doc generators that have TOC for headers

https://hexdocs.pm/phoenix/Phoenix.Controller.html is very close, in the sense that it also has header sections directly alongside functions and types.

Another example, referenced as part of the [early sidebar discussion](rust-lang#37856) that added methods, Ruby will show a table of contents in the sidebar (for example, on the [ARGF](https://docs.ruby-lang.org/en/master/ARGF.html) class). According to their changelog, [they added it in 2013](https://github.com/ruby/rdoc/blob/06137bde8ccc48cd502bc28178bcd8f2dfe37624/History.rdoc#400--2013-02-24-).

Haskell seems to mix text and functions even more freely than Elixir. For example, this [Naming conventions](https://hackage.haskell.org/package/base-4.19.0.0/docs/Control-Monad.html#g:3) is plain text, and is immediately followed by functions. And the [Pandoc top level](https://hackage.haskell.org/package/pandoc-3.1.11.1/docs/Text-Pandoc.html) has items split up by function, rather than by kind. Their TOC matches exactly with the contents of the page.

### Doc generators that don't have header TOC, but still have headers

Elm, interestingly enough, seems to have the same setup that Rust used to have: sibling navigation between modules, and no index within a single page. [They keep Haskell's habit of named sections with machine-generated type signatures](https://package.elm-lang.org/packages/elm/browser/latest/Browser-Dom), though.

[PHP](https://www.php.net/manual/en/book.datetime.php), like elm, also has a right-hand sidebar with sibling navigation. However, PHP has a single page for a single method, unlike Rust's page for an entire "class." So even though these pages have headers, it's never more than ten at most. And when they have guides, those guides are also multi-page.

## Unresolved questions

* Writing recommendations for anyone who wants to take advantage of this.
* Right now, it does not line wrap. That might be a bad idea: a lot of these are getting truncated.
* Split sidebars, which I [tried implementing](https://rust-lang.zulipchat.com/#narrow/stream/266220-t-rustdoc/topic/Table.20of.20contents), are not required. The TOC can be turned off, if it's really a problem. Implemented in rust-lang#120818, but needs more, separate, discussion.

## Future possibilities

I would like to do a better job of distinguishing global navigation from local navigation. Rustdoc has a pretty reasonable information architecture, if only we did a better job of communicating it.

This PR aims, mostly, to help doc authors help their users by writing docs that can be more effectively skimmed. But it doesn't do anything to make it easier to tell the TOC and the Module Nav apart.

…-rtems-arm-xilinx-zedboard, r=tgross35

Add target support for RTEMS Arm

# `armv7-rtems-eabihf`

This PR adds a new target for the RTEMS RTOS. To get things started it focuses on Xilinx/AMD Zynq-based targets, but in theory it should also support other armv7-based board support packages in the future.
Given that RTEMS has support for many POSIX functions it is mostly enabling corresponding unix features for the new target.
I also previously started a PR in libc (rust-lang/libc#3561) to add the needed OS specific C-bindings and was told that a PR in this repo is needed first. I will update the PR to the newest version after approval here.
I will probably also need to change one line in the backtrace repo.

Current status is that I could compile rustc for the new target locally (with the updated libc and backtrace) and could compile binaries, link, and execute a simple "Hello World" RTEMS application for the target hardware.

> A proposed target or target-specific patch that substantially changes code shared with other targets (not just target-specific code) must be reviewed and approved by the appropriate team for that shared code before acceptance.

There should be no breaking changes for existing targets. Main changes are adding corresponding `cfg` switches for the RTEMS OS and adding the C binding in libc.

# Tier 3 target 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 do the maintenance (for now) further members of the RTEMS community will most likely join once the first steps have been done.

> - 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 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.
>     - If possible, use only letters, numbers, dashes and underscores for the name. Periods (`.`) are known to cause issues in Cargo.

The proposed triple is `armv7-rtems-eabihf`

> - 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.
>     - Anything added to the Rust repository must be under the standard Rust license (`MIT OR Apache-2.0`).
>     - 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.

The tools consists of the cross-compiler toolchain (gcc-based). The RTEMS kernel (BSD license) and parts of the driver stack of FreeBSD (BSD license). All tools are FOSS and publicly available here: https://gitlab.rtems.org/rtems
There are also no new features or dependencies introduced to the Rust code.

> - 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.

N/A to me. I am not a reviewer nor Rust team member.

> - 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.

`core` and `std` compile. Some advanced features of the `std` lib might not work yet. However, the goal of this tier 3 target it to make it easier for other people to build and run test applications to better identify the unsupported features and work towards enabling them.

> - 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.

Building is described in platform support doc. Running simple unit tests works. Running the test suite of the stdlib is currently not that easy. Trying to work towards that after the this target has been added to the nightly.

> - 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.

Understood.

>     - 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.

Ok

> - 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.

I think, I didn't add any breaking changes for any existing targets (see the comment regarding features above).

> - Tier 3 targets must be able to produce assembly using at least one of rustc's supported backends from any host target.

Can produce assembly code via the llvm backend (tested on Linux).

>
> If a tier 3 target stops meeting these requirements, or the target maintainers no longer have interest or time, or the target shows no signs of activity and has not built for some time, or removing the target would improve the quality of the Rust codebase, we may post a PR to remove it; any such PR will be CCed to the target maintainers (and potentially other people who have previously worked on the target), to check potential interest in improving the situation.GIAt this tier, the Rust project provides no official support for a target, so we place minimal requirements on the introduction of targets.

Understood.

r? compiler-team

CI: rfl: add more tools and steps

This will add some time for the tool building -- the actual steps should be quick, though, and allows us to cover quite a few more tools and unstable features in use.

Please see the individual commits for a few details.

Cc: `@GuillaumeGomez` `@tgross35`
r? `@Kobzol`
try-job: x86_64-rust-for-linux

… r=albertlarsan68

warn the user if the upstream master branch is old

fixes rust-lang#129528

…nters-feature-gate, r=wesleywiser

Arbitrary self types v2: pointers feature gate.

The main `arbitrary_self_types` feature gate will shortly be reused for a new version of arbitrary self types which we are amending per [this RFC](https://github.com/rust-lang/rfcs/blob/master/text/3519-arbitrary-self-types-v2.md). The main amendments are:

* _do_ support `self` types which can't safely implement `Deref`
* do _not_ support generic `self` types
* do _not_ support raw pointers as `self` types.

This PR relates to the last of those bullet points: this strips pointer support from the current `arbitrary_self_types` feature. We expect this to cause some amount of breakage for crates using this unstable feature to allow raw pointer self types. If that's the case, we want to know about it, and we want crate authors to know of the upcoming changes.

For now, this can be resolved by adding the new
`arbitrary_self_types_pointers` feature to such crates. If we determine that use of raw pointers as self types is common, then we may maintain that as an unstable feature even if we come to stabilize the rest of the `arbitrary_self_types` support in future. If we don't hear that this PR is causing breakage, then perhaps we don't need it at all, even behind an unstable feature gate.

[Tracking issue](rust-lang#44874)

This is [step 4 of the plan outlined here](rust-lang#44874 (comment))

…ulted, r=petrochenkov

Make supertrait and implied predicates queries defaulted

r? `@ghost` only last commit is meaningful

Update docs of `missing_abi` lint

The lint docs still said that function ABIs other than "C" have not been added yet.

`@rustbot` labels: +A-docs +A-lint

Stabilize `waker_getters`

Tracking issue: rust-lang#96992

FCP completed on the tracking issue a while ago. It's not clear whether the libs-api team wanted the `RawWaker` methods moved to `Waker` or went back to the current API after further discussion. `@Amanieu` [wrote "This is just waiting for someone to submit a stabilization PR."](rust-lang#96992 (comment)) so I'm doing just that in hopes of nudging this along.

Edit: Moved the `data` and `vtable` methods from `RawWaker` to `Waker` and added `Waker::new` per rust-lang#96992 (comment)

```rs
impl Waker {
  pub const unsafe fn new(data: *const (), vtable: &'static RawWakerVTable) -> Self;
  pub fn data(&self) -> *const ();
  pub fn vtable(&self) -> &'static RawWakerVTable;
}
```

Closes rust-lang#96992

…bzol

remove deprecated option `rust.split-debuginfo`

This option was deprecated in February, it should be safe to remove it now.