WASI threads, implementation of wasm32-wasi-preview1-threads target
This PR adds a target proposed in https://github.com/rust-lang/compiler-team/issues/574 by `@abrown` and implementation of `std::thread::spawn` for the target `wasm32-wasi-preview1-threads`
### Tier 3 Target Policy
As tier 3 targets, the new targets are required to adhere to [the tier 3 target policy](https://doc.rust-lang.org/nightly/rustc/target-tier-policy.html#tier-3-target-policy) requirements. This section quotes each requirement in entirety and describes how they are met.
> - 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.)
See [src/doc/rustc/src/platform-support/wasm32-wasi-preview1-threads.md](https://github.com/rust-lang/rust/pull/112922/files#diff-a48ee9d94f13e12be24eadd08eb47b479c153c340eeea4ef22276d876dfd4f3e).
> - 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 target is using the same name for $ARCH=wasm32 and $OS=wasi as existing Rust targets. The suffix `preview1` introduced to accurately set expectations because eventually this target will be deprecated and follows [MCP 607](https://github.com/rust-lang/compiler-team/issues/607). The suffix `threads` indicates that it’s an extension that enables threads to the existing target and it follows [MCP 574](https://github.com/rust-lang/compiler-team/issues/574) which describes the rationale behind introducing a separate target.
> - 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.
This PR does not introduce any new dependency.
The new target doesn’t support building host tools.
> 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.
The full standard library is available for this target as it’s an extension to an existing target that has already supported it.
> 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.
Only manual test running is supported at the moment with some tweaks in the test runner codebase. For build and running tests see [src/doc/rustc/src/platform-support/wasm32-wasi-preview1-threads.md](https://github.com/rust-lang/rust/pull/112922/files#diff-a48ee9d94f13e12be24eadd08eb47b479c153c340eeea4ef22276d876dfd4f3e).
> - 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.
> - 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.
I acknowledge these requirements and intend to ensure they are met.
Change default panic handler message format.
This changes the default panic hook's message format from:
```
thread '{thread}' panicked at '{message}', {location}
```
to
```
thread '{thread}' panicked at {location}:
{message}
```
This puts the message on its own line without surrounding quotes, making it easiser to read. For example:
Before:
```
thread 'main' panicked at 'env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`', src/main.rs:4:6
```
After:
```
thread 'main' panicked at src/main.rs:4:6:
env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`
```
---
See this PR by `@nyurik,` which does that for only multi-line messages (specifically because of `assert_eq`): https://github.com/rust-lang/rust/pull/111071
This is the change that does that for *all* panic messages.
Improve the rust style guide doc
- Make the levels of headings consistent in this whole document.
Before this change, the highest level of headings in some file is level 1, but in most of the files the that is level 2. Not consistent.
- Fix some headings
- Follow the markdown linter advices
- Remove redundant empty lines
- Surround each heading with empty lines
- Use the same symbol for different levels of unordered list entries
Directly link more target docs
Some platforms were not linked from platform-support.md
This fixes that, but errs towards extremely conservative, only directly linking platform docs if the docs actively mention the target, as otherwise I do not necessarily know if there was a reason for the omission.
bootstrap: use git merge-base for LLVM CI download logic
Fixes https://github.com/rust-lang/rust/issues/101907
I tested this with a local branch that has extra merge commits due to Miri, and it worked fine there. But I am sure there are tons of other situations I did not think of...
r? `@jyn514`
style-guide: Document style editions, start 2024 style edition
Link to a snapshot for the 2015/2018/2021 style edition.
This is a draft, because I'd like to wait for a few style guide fixes to merge
before snapshotting the 2015/2018/2021 style edition:
- https://github.com/rust-lang/rust/pull/113145
- https://github.com/rust-lang/rust/pull/113380
- https://github.com/rust-lang/rust/pull/113384
- https://github.com/rust-lang/rust/pull/113385
- https://github.com/rust-lang/rust/pull/113386
- https://github.com/rust-lang/rust/pull/113392
I'd like to wait for these for two reasons: to make it easier to see the
differences between the 2015/2018/2021 style edition and the 2024 style
edition (without the noise of guide-wide changes), and to minimize confusion so
that bugfixes to the style guide that we include in the previous edition don't
look like they're only part of the 2024 style edition.
I've used "Miscellaneous `rustfmt` bugfixes" as a starting point for the list
of 2024 changes, for now. We can update that when we add more 2024 changes.
The section added in this PR can then serve as a baseline for our drafts of
2024 style edition changes.
In the meantime, I'd like to get someone from `@rust-lang/style` to review and
approve the text here; I'll update it with a commit hash when the above PRs
have merged.
Some platforms were not linked from platform-support.md
This fixes that, but errs towards extremely conservative,
only directly linking platform docs if the docs actively
mention the target, as otherwise I do not necessarily
know if there was a reason for the omission.
Update Clippy
r? `@Manishearth`
This is a bit delayed, because I thought it is a difficult conflict resolution and didn't have time for that over the weekend. Turns out, I just used the wrong merge base and it was actually easy... Don't do syncs in the middle of the night (even though I broke this rule with this PR again).
Update lexer emoji diagnostics to Unicode 15.0
This replaces the `unic-emoji-char` dep tree (which hasn't been updated for a while) with `unicode-properties` crate which contains Unicode 15.0 data.
Improves diagnostics for added emoji characters in recent years. (See tests).
cc #101840
cc ``@Manishearth``
Rollup of 9 pull requests
Successful merges:
- #114111 (Improve test case for experimental API remove_matches)
- #114169 (refactor builtin unsize handling, extend comments)
- #114182 (clean up after 113312)
- #114193 (Update lexer emoji diagnostics to Unicode 15.0)
- #114200 (Detect trait upcasting through struct tail unsizing in new solver select)
- #114228 (Check lazy type aliases for well-formedness)
- #114267 (Map RPITIT's opaque type bounds back from projections to opaques)
- #114269 (Migrate GUI colors test to original CSS color format)
- #114286 (Add missing feature gate in multiple_supertrait_upcastable doc)
r? `@ghost`
`@rustbot` modify labels: rollup
Check lazy type aliases for well-formedness
Previously we didn't check if `T: Mul` holds given lazy `type Alias<T> = <T as Mul>::Output;`.
Now we do. It only makes sense.
`@rustbot` label F-lazy_type_alias
r? `@oli-obk`
Move BOLT from `bootstrap` to `opt-dist`
Currently, we use BOLT to optimize LLVM for x64 Linux. The BOLT instrumentation and optimization step is implemented in `bootstrap`, but it was always quite hacky, because BOLT works quite differently than PGO. Rather than building an instrumented artifact, it takes an already built artifact and instruments it in-place. This is not a good fit for the bootstrap caching mechanism, and it meant that we had to run BOLT "on-the-fly" when packaging LLVM artifacts into the created sysroot.
The BOLT code was also really only used by the PGO script (now called `opt-dist`) and nothing else, so it was quite hardcoded for this one single usage. And even if someone wanted to use the `--llvm-bolt-profile-[use/generate]` bootstrap flags outside of the PGO script, they would also need to implement profile gathering, as this is not performed by bootstrap anyway.
I think that it could be more practical to move the BOLT logic to the `opt-dist` tool instead. This simplifies bootstrap, removes unneeded implementation of BOLT caching (we will now do it exactly once - no need to check if it has been performed already when bootstrap copies `libLLVM.so` around multiple times) and removes two BOLT-specific bootstrap flags, and also one special case for building LLVM (instead I pass the linker flags with `--set llvm.ldflags` from `opt-dist` now).
There are also a few disadvantages to this new approach:
- We have to guess/find the path to the built `libLLVM.so` file (but currently this is quite easy, it's just in `stage2/lib`).
- We have to provide the BOLT profile externally to bootstrap, so that it is packaged into the reproducible artifacts archive. Doesn't seem like a big deal to me.
- We are depending on some inner behavior of boostrap in `opt-dist` (namely, that `libLLVM.so` is hardlinked). But we do that for many other things in the `opt-dist` tool anyway, it's tied quite closely to bootstrap.
I would like to go back to my attempts to also use BOLT for `librustc_driver.so`, and I think that it might be a bit simpler if I also do it from the `opt-dist` tool, so this is the first step towards that.
Anyway, let me know what you think about this. It's just a refactoring in a way, no big deal.
r? bootstrap
Rewrite miri script in rust
This is a sketch of a rewrite of miri script in Rust. It does not include changes made in https://github.com/rust-lang/miri/pull/2908 yet. Environment variables are not properly propagated yet, which is something I plan to address.
This PR is mostly a heads-up about the ongoing effort and it's state.
It's definitely not the cleanest code I've seen in my life, but my first goal was feature/interface parity. I will iterate on it a bit before marking it as ready.
I wonder though how this should be integrated/tested. Are you aware of anyone using `./miri` in their scripts?
I guess we should keep existing `miri` script in place and let it run miri-script package directly?
CI should probably `cargo check` this package as well.
Fixes#2883
Ralf Jung