rust/compiler/rustc_target
Matthias Krüger 7dc211f5ce
Rollup merge of #108795 - thomcc:x86_64h-target, r=wesleywiser
Add support for the x86_64h-apple-darwin target

See https://github.com/rust-lang/compiler-team/issues/599 for MCP.

r? compiler-team

CC `@BlackHoleFox` who recently overhauled the apple target code in `rustc-target`.

## Target Support Checklist

> - 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'm the designated developer.

> - 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.

This uses the same naming conventions used for the other macOS targets (`-apple-darwin`), combined with the convention used by LLVM for the `x86_64h` targets. LLVM's convention matches the architecture name used when invoking various tools such as `lipo`, `arch`, and (IMO) there's not really a compelling reason to depart from it.

> - 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 think this is especially likely, although I suppose someone could mistake it for `x86_64-apple-darwin`.

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

👍

> - 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.

It does not.

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

It is.

> - 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.

There are no new dependencies that don't also apply to `x86_64-apple-darwin`.

> - 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.

This has the same requirements as the other macOS targets (e.g. `x86_64-apple-darwin` and similar).

> - "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.

No change here.

> - 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 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 standard library tests seem to pass.

> - 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.

> - 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.

Noted. This target is nearly identical to `x86_64-apple-darwin`, so this is
unlikely to cause issues anyway.

> - 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.

👍
2023-04-20 17:59:53 +02:00
..
src Rollup merge of #108795 - thomcc:x86_64h-target, r=wesleywiser 2023-04-20 17:59:53 +02:00
Cargo.toml Add try_canonicalize to rustc_fs_util and use it over fs::canonicalize 2023-03-16 21:50:23 +01:00
README.md Fix outdated crate names in compiler docs 2021-04-08 11:12:14 -05:00

rustc_target contains some very low-level details that are specific to different compilation targets and so forth.

For more information about how rustc works, see the rustc dev guide.