Add QNX/nto support

[flba-eb]

This patch adds support to the QNX/nto operating system. This target is supported by Rust: rust-lang/rust#102701.

cc @gh-tr

[newpavlov]

Is it possible to add a build job to our CI for this target?

[josephlr]

You can add this target to our CI by adding x86_64-pc-nto-qnx7.1.0 after this line.

[flba-eb]

Is it possible to add a build job to our CI for this target?

I would love to have QNX/nto builds in CI, but I think it is not feasible right now because a license key is required. Also, the license seems not to work well in containers but works best with real hardware. I will forward this question to check if there is a possibility.

[josephlr]

Is it possible to add a build job to our CI for this target?

I would love to have QNX/nto builds in CI, but I think it is not feasible right now because a license key is required. Also, the license seems not to work well in containers but works best with real hardware. I will forward this question to check if there is a possibility.

That makes sense, we don't need to run the code, The line I suggested adding would only build the code, not execute it. Obviously actually running on qnx is better, but just building in our CI ensures that we don't inadvertently break things.

[flba-eb]

Is it possible to add a build job to our CI for this target?

I would love to have QNX/nto builds in CI, but I think it is not feasible right now because a license key is required. Also, the license seems not to work well in containers but works best with real hardware. I will forward this question to check if there is a possibility.

That makes sense, we don't need to run the code, The line I suggested adding would only build the code, not execute it. Obviously actually running on qnx is better, but just building in our CI ensures that we don't inadvertently break things.

Not using the official QNX/nto toolchain would be tricky, because a special linker is used: https://github.com/flba-eb/rust-lang-fork/blob/master/compiler/rustc_target/src/spec/nto_qnx_base.rs#L12
Also, we would need to link against a libc.so which exposes the symbol libc::__get_errno_ptr.

I suggest to go without the tests.

[josephlr]

Not using the official QNX/nto toolchain would be tricky, because a special linker is used:

I realize that we cannot link without access to an OS specific toolchain. This is not the only target where we have this issue. That is why the line I suggested adding just compiles the code, without linking or running it.

[newpavlov]

Compilation includes linking, no? Maybe we can use cargo check for the most basic testing?

[flba-eb]

I tested a bit with it but removed the test code again. We don't have (upstreamed) libc support yet (work in progress), which is why even cargo check does not work yet.

[josephlr]

I tested a bit with it but removed the test code again. We don't have (upstreamed) libc support yet (work in progress), which is why even cargo check does not work yet.

That's good to know, and one of the reasons we like to build code for new targets. cargo build and cargo check will only compile the rust code, it shouldn't need to link anything.

@newpavlov would you be okay accepting code that depends on not-yet-upstreamed libc support? Or should we just wait for the upstream libc changes before merging this?

[newpavlov]

@josephlr
I think it's better to wait. If someone needs the support right away, then they simply can temporarily patch getrandom dependency in addition to libc.

[josephlr]

@josephlr I think it's better to wait. If someone needs the support right away, then they simply can temporarily patch getrandom dependency in addition to libc.

Sounds reasonable.

@flba-eb feel free to ping this issue once the libc support for QNX/nto gets merged. Then I'd be happy to merge this.

[flba-eb]

@josephlr Ping! QNX support has been added to libc: rust-lang/libc#3038

[josephlr]

@josephlr Ping! QNX support has been added to libc: rust-lang/libc#3038

Awesome!! Can you bump the libc version the Cargo.toml file to include the release that has that PR, and add aarch64-unknown-nto-qnx710 to tests.yml here

[flba-eb]

@josephlr , done, please check. Check runs locally.

[josephlr]

The QNX tests are passing so I'm going to merge this. I'll fix the other tests in a followup PR.