This is implementing the MCP from rust-lang/compiler-team#493. It is
increasing the minimum requirements of a couple Tier 1 targets, and
others at lower tiers, so this should go through FCP sign-offs for both
`T-compiler` and `T-release`.
The new `linux-gnu` baseline is kernel 3.2 and glibc 2.17. We will also
take that kernel as the minimum floor for _all_ `*-linux-*` targets, so
it may be broadly assumed in the implementation of the standard library.
That does not preclude specific targets from having greater requirements
where it makes sense, like a new arch needing something newer, or a
platform like `linux-android` choosing a newer baseline.
Add Fuchsia platform support documentation
This documentation contains instructions for building and running binaries on Fuchsia using its provided SDK.
Add a `platform-support` entry to the rustc-docs for the different
`*-unknown-uefi` targets. This describes in detail how this platform
works, a few basic examples, and how to compile for the platform.
Red Hat is sponsoring my work on this platform, so I am putting myself
down as target maintainer. Co-maintainers are more than welcome to join
me in the effort. Communication is going on off-list to coordinate the
different efforts.
Note that the ultimate goal is to move the UEFI targets to Tier-2 so
bootloaders can be more easily supported in commercial products. This
documentation is the first step towards that goal, but should be a
viable documentation even for the current Tier-3 status of the targets.
I also want to point out that there is an ongoing GSoC-effort to port
the rust standard library to UEFI (by Ayush Singh). While this work is
not necessarily required to get to Tier-2, we definitely should
coordinate the efforts and update the documentation as soon as any such
ports are merged.
Note that the targets are already used by multiple commercial and non
commercial production systems, including, but not limited to:
* Tianocore-EDK2 (Official UEFI SDK by Intel) comes with rust support
in its staging repository (not part of any release, yet).
(https://github.com/tianocore/edk2-staging/tree)
* Intel's research program "Project Mu" uses the rust UEFI targets to
show possible future replacements for Tianocore-EDK2.
* The Rust OS "Redox" uses the UEFI targets for its bootloader.
(https://www.redox-os.org/)
* The hugely popular in-depth documentation of OS development in Rust
by Philipp Oppermann uses the UEFI targets.
(https://os.phil-opp.com/)
Signed-off-by: David Rheinsberg <david.rheinsberg@gmail.com>
Minor tweaks to rustc book summary formatting.
This includes a few minor tweaks to the summary/titles of chapters for the rustc book:
* Use a consistent chapter capitalization and hyphenation.
* Move "Codegen Options" underneath "Command-line Arguments". I feel like they are two closely related chapters, where codegen is just a subset of the total arguments.
* Move "Target Tier Policy" underneath "Platform Support". That chapter includes that policy for platform support, and thus I feel it is more closely related to that grouping.
Add missing rustc arg docs
Add documentation for recently added rustc args
`-C symbol-mangling-version` was stabilized in #90128.
`--json=future-incompat` was stabilized in #91535.
Add riscv32im-unknown-none-elf built-in target triple.
* Add built-in target `riscv32im-unknown-none-elf`.
* Update `platform-support.md` to list it as a Tier 3 target.
Below are details on how this target meets the requirements for tier 3:
> 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 with more experience around RISC-V 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 bare-metal targets.
> 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.
> 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. `std` cannot be used as this is a bare-metal target.
> 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=x86_64-unknown-none-elf` option to cross compile, just like any target. The target does 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.
Update to Ubuntu 20.04 and crosstool-ng 1.24.0. I've updated the
ct-ng config and then manually reset the kernel and glibc versions
to the oldest supported.
Specifically, we're updating from kernel 2.6.32.68 to 2.6.32.71
and glibc 2.11.1 to 2.12.1 here. The compiler toolchain is also
updated, but I don't think that's relevant for compatibility.
Use `optflag` for `--report-time`
Essentially, what is described here:
https://github.com/rust-lang/rust/issues/64888#issuecomment-1008047228
There is one difference. The comment proposes to add a
`--report-time-color` option. This change instead uses libtest's
existing `--color` option for that purpose.
