Assign maintainers for MIPS R6 targets

[Fearyncess]

Proposal

This is a proposal to assign target maintainers for MIPS R6 targets:

• mipsisa32r6-unknown-linux-gnu
• mipsisa32r6el-unknown-linux-gnu
• mipsisa64r6-unknown-linux-gnuabi64
• mipsisa64r6el-unknown-linux-gnuabi64

This proposal follows an earlier pull request from our colleague YunQiang Su, which introduced MIPS R6 support to Rust. As with Su, we are employees at CIP United Inc., the exclusive licensor and operator of MIPS IPs in Mainland China, Hong Kong S.A.R., and Macau S.A.R. Part of our operations include maintaining and improving open source software solutions for MIPS. Among which, Rust is considered a key open source support target. As we assign employees to work with specific open source software support (we are currently actively improving GNU toolchain and LLVM support), we would like to volunteer as the target maintainers for MIPS R6 targets.

MIPS Release 6 (R6) is the latest iteration of the MIPS ISA, which, for its adoption of the new "2008" NaN ABI among other changes, is functionally incompatible with many of the earlier releases (including the most widely used R2 ISA).

• Introduction to the MIPS64 Architecture v6.01
• The MIPS64 Instruction Set v6.06

There is currently no plan to promote this target to Tier 2, as MIPS R6 is still experimental in nature and much of its ecosystem needs further work to see use in production.

Tier-3 Acknowlegment

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.)

• Xuan Chen, @chenx97, henry.chen@oss.cipunited.com
• Walter Ji, @709924470, walter.ji@oss.cipunited.com
• Xinhui Yang, @Cyanoxygen, cyan@oss.cipunited.com
• Lain Yang, @Fearyncess, lain.yang@oss.cipunited.com

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.

The targets listed above are consistent with naming conventions adopted by GNU and LLVM.

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.

Acknowledged.

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.

Acknowledged. Work on open source support for MIPS R6-based systems is sponsored by CIP United, Inc.

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 target already has good support for std and we will continue to work to improve its 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 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 will be supplied in short order.

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.

Acknowledged.

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.

Acknowledged.

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.

Acknowledged.

Process

The main points of the Major Change Process are as follows:

• File an issue describing the proposal.
• A compiler team member or contributor who is knowledgeable in the area can second by writing @rustbot second.
  • Finding a "second" suffices for internal changes. If however, you are proposing a new public-facing feature, such as a -C flag, then full team check-off is required.
  • Compiler team members can initiate a check-off via @rfcbot fcp merge on either the MCP or the PR.
• Once an MCP is seconded, the Final Comment Period begins. If no objections are raised after 10 days, the MCP is considered approved.

You can read more about Major Change Proposals on forge.

Comments

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[rustbot]

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

cc @rust-lang/compiler @rust-lang/compiler-contributors

[wesleywiser]

@rustbot second

[apiraino]

@rustbot label -final-comment-period +major-change-accepted