building for Embedded RISC-V does not work

[wuyoli]

I'm trying to make a flake for Embedded Development on CH32V307 microcontrollers. I did get Cargo build working successfully, but nix build doesn't work. When trying to do so it fails with the following error:

> Running phase: buildPhase
       > error: no matching package named `compiler_builtins` found
       > location searched: directory source `/build/cargo-vendor-dir` (which is replacing registry `crates-io`)
       > required by package `std v0.0.0 (/nix/store/a9flgvs64klvknn49qrsw3xlqsznyc2g-rust-default-1.85.0-nightly-2025-01-01/lib/rustlib/src/rust/library/std)`
       >     ... which satisfies path dependency `std` (locked to 0.0.0) of package `sysroot v0.0.0 (/nix/store/a9flgvs64klvknn49qrsw3xlqsznyc2g-rust-default-1.85.0-nightly-2025-01-01/lib/rustlib/src/rust/library/sysroot)`

[wuyoli]

Am I doing something wrong or is this out of scope?

[oxalica]

Am I doing something wrong or is this out of scope?

Please provide the nix file you use, the command your run and the Rust project you are building, in order to find out what the issue is.

[wuyoli]

the following repo contains the code + flake:
https://tildegit.org/purelyserious/ch32v307-blink-rust

[wuyoli]

do you have any ideas how to build this with nix?

[tsheinen]

I just ran into a similar problem -- the issue is unrelated to rust-overlay. It's a problem with the combination of vendoring and -Zbuild-std because std requires out-of-tree crates. Naersk will take an extra Cargo.lock as an argument since #328 and that's probably the easiest route forward? Alternatively if you add all the std deps to your dependency graph somewhere (dev-dependencies works) then the regular nixpkgs vendor will work.

naersk.buildPackage {
  src = ./.;
  additionalCargoLock = "${rust-toolchain}/lib/rustlib/src/rust/library/Cargo.lock";
};

[wuyoli]

the lib/rustlib/src folder doesn't exist in my rust-toolchain. Did you change something with it?

[tsheinen]

it needs the rust-src component

[wuyoli]

Thank you! I implemented your suggestions (the current version of my source is here. The error about compiler_builtins is now gone, but I now have a different error:

 error: could not compile `qingke` (lib) due to 1 previous error
 warning: build failed, waiting for other jobs to finish...
 error: As tested on QingKe V4, most likely the atomics are broken,
        please validate the atomic instruction on the hardware using
        something like litmus test suite before trusting them.
   --> /sources/qingke-0.5.0-c0230c5310b68c08a3cf8b59fbeec3e9d8e352bc6500f62cbaf9c677f42c8dfc/src/lib.rs:25:1
    |
 25 | / compile_error!(
 26 | |     "As tested on QingKe V4, most likely the atomics are broken,
 27 | | please validate the atomic instruction on the hardware using
 28 | | something like litmus test suite before trusting them."
 29 | | );
    | |_^

the "normal" cargo build is still working fine though, even with --release, which was the only other difference in between the two ways of doing things I could think of.

not sure how related this still is, but I don't think upstream (ch32rs/quingke) is the problem since it works fine with cargo build. I found this commit which seems like it should fix this, but it doesn't. (the behaviour is the same both with a repo generated before and one generated after.)

[SFrijters]

I have done some similar work for ESP32C3, maybe you can get something out of it: https://github.com/SFrijters/nix-qemu-esp32c3-rust-example .

[wuyoli]

Thank you, but I don't think this helps, because the Error I'm getting is in the Quingke crate and seems like the it should have already been fixed upstream here, the weird thing is: it works fine when compiling with cargo build, but not when running nix build.