added support for GNU/Hurd

[xevor11]

adding support for i686-unknown-hurd-gnu

[rustbot]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @joshtriplett (or someone else) soon.

Please see the contribution instructions for more information. Namely, in order to ensure the minimum review times lag, PR authors and assigned reviewers should ensure that the review label (S-waiting-on-review and S-waiting-on-author) stays updated, invoking these commands when appropriate:

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[rustbot]

These commits modify compiler targets.
(See the Target Tier Policy.)

[Urgau]

Could you address the requirements of the target tier policy in the PR description (Tier 3 in your case). As well as in the src/doc/rustc/src/platform-support.md. Example here.

Also, you may want to split your PR in two: the first adding the compiler target and the second adding support for the Standard Library.
r? compiler

[Urgau]

Suggested change

	(Some(Mode::Std), "target_os", Some(&["teeos", "hurd"])),
	// #[cfg(bootstrap)] hurd
	(Some(Mode::Std), "target_os", Some(&["teeos", "hurd"])),

[sthibaul]

right, done so!

[sthibaul]

Tier 3 target policy

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.)

We added myself as target maintainer.

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.

We used the same target named as used in llvm: i686-unknown-hurd-gnu

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.

GNU tools use i686-unknown-gnu and that indeed sometimes bring confusion, that's why we used the llvm triplet.

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

That's alright 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.

The target legal terms are basically like the Linux ecosystem.

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).

Agreed.

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.

GNU/Hurd uses the GNU toolchain, like Linux.

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.

The whole point of the GNU project is exactly that :)

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 is the same situation as linux, since we use the GNU toolchain and libc.

Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party.

That is also the kind of goals of the GNU project :)

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),

We do have core/alloc/std.

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.

The documentation was added. Running tests can be done in a qemu VM for instance, pre-built installed images are available.

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.

Ok, sure!

Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target,

We believe our additions didn't break anything, and we will watch CI anyway.

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.

Sure!

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.

Ok!

[bors]

💔 Test failed - checks-actions

[sthibaul]

error: unexpected `cfg` condition value
  --> compiler/rustc_data_structures/src/flock/unix.rs:24:23
   |
24 |         #[cfg(not(all(target_os = "hurd", target_arch = "x86")))]
   |
   |
   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `openbsd`, `psp`, `redox`, `solaris`, `solid_asp3`, `teeos`, `tvos`, `uefi`, `unknown`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`
   = note: `-D unexpected-cfgs` implied by `-D warnings`

? How can that happen? Isn't this

diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 1e001fae8ab..301d8a7c3fd 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -133,7 +133,8 @@ pub unsafe fn setup(_build: &mut crate::Build) {}
     // #[cfg(bootstrap)]
     (Some(Mode::Std), "target_vendor", Some(&["unikraft"])),
     (Some(Mode::Std), "target_env", Some(&["libnx"])),
-    (Some(Mode::Std), "target_os", Some(&["teeos"])),
+    // #[cfg(bootstrap)] hurd
+    (Some(Mode::Std), "target_os", Some(&["teeos", "hurd"])),
     // #[cfg(bootstrap)] mips32r6, mips64r6
     (
         Some(Mode::Std),

supposed to make "hurd" a valid value for target_os?

[sthibaul]

Or do we need to first add the declaration in bootstrap, wait for a weekly beta compiler to be built, and add the rest?

[b-naber]

It doesn't make sense to me why we would get that error if CI already compiles successfully. Looking at how the builtin condition values for cfg are constructed all the values for target_os for this target should be available. I don't know... doesn't really seem like the usual spurious error, but let's try again.

@bors retry

[bjorn3]

You need one for Mode::Rustc too if you want to use it in rustc.

[sthibaul]

Ok, done so, thanks!

[bjorn3]

@bors r=b-naber

[bors]

📌 Commit dcea770 has been approved by b-naber

It is now in the queue for this repository.

[bors]

⌛ Testing commit dcea770 with merge f73d376...

[bors]

☀️ Test successful - checks-actions
Approved by: b-naber
Pushing f73d376 to master...

[rust-timer]

Finished benchmarking commit (f73d376): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.4%	[-0.4%, -0.4%]	2
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.6%	[-2.6%, -2.6%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-2.6%	[-2.6%, -2.6%]	1

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 633.468s -> 632.84s (-0.10%)
Artifact size: 317.47 MiB -> 317.62 MiB (0.05%)