kmc-solid: Fix wait queue manipulation errors in the `Condvar` implementation
This PR fixes a number of bugs in the `Condvar` wait queue implementation used by the [`*-kmc-solid_*`](https://doc.rust-lang.org/nightly/rustc/platform-support/kmc-solid.html) Tier 3 targets. These bugs can occur when there are multiple threads waiting on the same `Condvar` and sometimes manifest as an `unwrap` failure.
Refactor sidebar printing code
This is the refactoring parts of #92660, plus the trait aliases capitalization
consistency fix. I think this will be necessary for #92658.
r? `@GuillaumeGomez`
Support custom options for LLVM build
The LLVM build has a lot of options that rustbuild doesn't need to know about. We should allow the user to customize the LLVM build directly.
Here are some [example customizations][recipe] we'd like to do.
[recipe]: 90105e5e4e/recipes/contrib/clang_toolchain.py (579)
add kernel target for RustyHermit
Currently, we are thinking to use *-unknown-none targets instead to define for every platform our own one (see hermitcore/rusty-hermit#197). However, the current target aarch64-unknown-none-softfloat doesn't support dynamic relocation. Our RustyHermit project uses this feature and consequently we define a new target aarch64-unknown-hermitkernel to support it.
> 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 would be willing to be a target maintainer, though I would appreciate if others volunteered to help with that as well.
> 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.
Uses the same naming as the LLVM target, and the same convention as many other kernel targets (e.g. `x86_64_unknown_none_linuxkernel`). In contrast to the bare-metal target for the aarch64 architecture, the unikernel requires dynamic relocation.
> 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.
I don't believe there is any ambiguity here. It use the same convention on x86_64 architecture.
> 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.
I don't see any legal issues here.
> 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.
If the target supports building host tools (such as rustc or cargo), those host tools must not depend on proprietary (non-FOSS) libraries, other than ordinary runtime libraries supplied by the platform and commonly used by other binaries built for the target. 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.
Targets should not require proprietary (non-FOSS) components to link a functional binary or library.
"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.
I see no issues with any of the above.
> 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.
Only relevant to those making approval decisions.
> 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 `alloc` can be used. For `std` exists already the target `aarch64_unknown_hermit`, which enables FPU support.
> 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 tests (even if they do not pass), the documentation must explain how to run tests for the target, using emulation if possible or dedicated hardware if necessary.
Use `--target=aarch64_unknown_hermitkernel` option to cross compile. The target does currently not support running tests.
> 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.
I don't foresee this being a problem.
> 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.
No other targets should be affected by the pull request.
Ensure that queries only return Copy types.
This should pervent the perf footgun of returning a result with an expensive `Clone` impl (like a `Vec` of a hash map).
I went for the stupid solution of allocating on an arena everything that was not `Copy`. Some query results could be made Copy easily, but I did not really investigate.
Fix typo in `std::fmt` docs
Hey!
Reading the docs (https://doc.rust-lang.org/std/fmt/#named-parameters), this seems like a typo?
The docs here also seem to mix “named argument” and “named parameter”? Intentional? Mistake?
debuginfo: Fix DW_AT_containing_type vtable debuginfo regression
This PR brings back the `DW_AT_containing_type` attribute for vtables after it has accidentally been removed in #89597.
It also implements a more accurate description of vtables. Instead of describing them as an array of void pointers, the compiler will now emit a struct type description with a field for each entry of the vtable.
r? ``@wesleywiser``
This PR should fix issue https://github.com/rust-lang/rust/issues/93164.
~~The PR is blocked on https://github.com/rust-lang/rust/pull/93154 because both of them modify the `codegen/debug-vtable.rs` test case.~~
Better suggestions when user tries to collect into an unsized `[_]`
1. Extend the predicate on `rustc_on_unimplemented` to support substitutions like note, label, etc (i.e. treat it as a `OnUnimplementedFormatString`) so we can have slightly more general `rustc_on_unimplemented` special-cases.
2. Add a `rustc_on_unimplemented` if we fail on `FromIterator<A> for [A]` which happens when we don't explicitly collect into a `vec<A>`, but then pass the return from a `.collect` call into something that takes a slice.
Fixes#91423
The new code is much simpler and easier to understand. In fact, the old
code actually had a subtle bug where it excluded a few item types,
including trait aliases, from the sidebar, even though they are rendered
on the page itself! Now, all sections should show up in the sidebar.
Refactor query system to maintain a global job id counter
This replaces the per-shard counters with a single global counter, simplifying
the JobId struct down to just a u64 and removing the need to pipe a DepKind
generic through a bunch of code. The performance implications on non-parallel
compilers are likely minimal (this switches to `Cell<u64>` as the backing
storage over a `u64`, but the latter was already inside a `RefCell` so it's not
really a significance divergence). On parallel compilers, the cost of a single
global u64 counter may be more significant: it adds a serialization point in
theory. On the other hand, we can imagine changing the counter to have a
thread-local component if it becomes worrisome or some similar structure.
The new design is sufficiently simpler that it warrants the potential for slight
changes down the line if/when we get parallel compilation to be more of a
default.
A u64 counter, instead of u32 (the old per-shard width), is chosen to avoid
possibly overflowing it and causing problems; it is effectively impossible that
we would overflow a u64 counter in this context.
