riscv64gc-unknown-linux-gnu support

[tblah]

Current status

rustup builds on riscv, tests pass*, and rustup can install toolchains for supported host architectures.

Tested on Debian using Qemu full system emulation.

To resolve WIP status

• rust-lang/rust needs to publish official riscv64gc-unknown-linux-gnu host toolchains for rustup on riscv to be useful.
• rust-lang/rust needs to publish a docker image to allow CI for riscv64gc-unknown-linux-gnu to run
• Add RLIMIT_* constants for RISC-V 64-bit GNU/Linux and minor fixes for type definitions libc#1745 needs merging so that ca3cec0 can go away

[kinnison]

Obviously I can't merge while effective-limits isn't released, and with that CI change, but the rest could go in immediately if you wanted to either split the PR up, or simplify it in the short term.

[kinnison]

I take it that there needs to be a patch merged and a new release made for this?

[mati865]

@tblah regarding your question in infra docker channel.

rustc -vV
rustc 1.41.0-dev
binary: rustc
commit-hash: unknown
commit-date: unknown
host: x86_64-unknown-linux-gnu
release: 1.41.0-dev
error: couldn't load codegen backend "/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/codegen-backends/librustc_codegen_llvm-llvm.so": "/lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.27\' not found (required by /usr/local/lib/rustlib/x86_64-unknown-linux-gnu/codegen-backends/librustc_codegen_llvm-llvm.so)"

^ this is not the Rust that you have installed with rustup.
Missing rustup default stable somewhere perhaps?

[tesuji]

if bump libc, why not cargo update -p libc and remove this change.

[tblah]

The libc changes aren't in a released version yet so I think I have to tell cargo to fetch libc master branch instead of a release.

[tblah]

Thanks @mati865 it seems to work now that it is building using the stable tool-chain.

[tblah]

@kinnison sorry for the delay while I played with CI.

CI will only work with the effective-limits change, so is the next step to merge only 342642d and make a new WIP PR for CI?

[kinnison]

As discussed on IRC, let's wait for the libc fix and then consider merging everything cleanly instead

[kinnison]

We'll need to undo the effective-limits thing and instead update libc and friends when the releases are done. So let's not consider merging before then.

[tblah]

An update on the status of this:

The libc version bump landed a little while ago. The last piece of the puzzle is to bump the version of libc required by effective-limits so that rustup is forced to upgrade. I have a PR open for this.

[kinnison]

Fantastic, I imagine @rbtcollins will get to that PR when he has a chance. I think we might be worried about something else with E-L on another issue, so hopefully that could be soon.

[kinnison]

Once that's done, if you could also rebase so that we're good in terms of the CI etc, that'd be excellent.

[rbtcollins]

effective-limits stuff has merged, so this should be cleanup-able now

[tblah]

Thanks @rbtcollins

@kinnison this should be ready for review

[kinnison]

Fundamentally good stuff. I'm slightly worried that people might expect a released rustup with the shell script changes, but we can explain it's not there yet, so I'm okay with that change there. But I think we need a skip-stable in the action template, and then we'll need the workflows regenerating (as a separate commit)

[kinnison]

This is getting very close. Could you please rebase to fold your two CI changes together; and then as a new commit add the result of running sh ci/actions-templates/gen-workflows.sh which will update the contents of the real workflows.

I'm okay if that results in failed CI on the PR for now, but I want to check things are updated properly (and not updated as appropriate for the stable build fr.ex)

[tblah]

@kinnison I've done the rebase. Running ci/actions-templates/gen-workflows.sh doesn't change anything because riscv64gc-unknown-linux-gnu is skip-pr skip-master skip-stable (it is skipped in all cases)

[kinnison]

Cool, let's hope your efforts to get riscv-linux to tier two complete soon, so we can consider a rustup release with it :D