yosys-slang: init at 0-unstable-2025-12-15

[luciengaitskell]

Add yosys-slang yosys plugin: https://github.com/povik/yosys-slang
This plugin is provided in the OSS CAD Suite and therefore would be nice to have as a nixpkg.

Can show the plugin loaded with:

yosys -m result/share/yosys/plugins/slang.so -p "help read_slang"

Things done

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
  • Ran manual tests with Yosys to confirm the extension-provided read_slang ran.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

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Add a 👍 reaction to pull requests you find important.

[luciengaitskell]

(fixing commit history)

[luciengaitskell]

Updated to use the new by-name mechanism instead of callPackage (used by existing Yosys plugins)

https://github.com/NixOS/nixpkgs/actions/runs/20399639009/job/58620137360#logs

[Emin017]

Most of it LGTM, but there are a few minor issues.

And I also noticed that yosys-slang/GitRevision appears to retrieve the revision via Git, but the packaging approach in this PR does not currently support that. It would be great if this could be supported.

[povik]

And I also noticed that yosys-slang/GitRevision appears to retrieve the revision via Git, but the packaging approach in this PR does not currently support that. It would be great if this could be supported.

Is the issue that fetchFromGithub is not a git checkout per se and does not populate .git? Version information can also be supplied to cmake with -DYOSYS_SLANG_REVISION=foo -DSLANG_REVISION=bar.

If you'd like to see something changed upstream to make packaging easier feel free to make suggestions.

[Emin017]

And I also noticed that yosys-slang/GitRevision appears to retrieve the revision via Git, but the packaging approach in this PR does not currently support that. It would be great if this could be supported.

Is the issue that fetchFromGithub is not a git checkout per se and does not populate .git? Version information can also be supplied to cmake with -DYOSYS_SLANG_REVISION=foo -DSLANG_REVISION=bar.

If you'd like to see something changed upstream to make packaging easier feel free to make suggestions.

@povik I think this can be addressed by setting leaveDotGit = true in fetchFromGithub, which would preserve the .git directory (Sorry, I forgot about this option earlier). With that in place, we wouldn’t need to make any changes upstream.

[povik]

Sounds good

[luciengaitskell]

@Emin017 added leaveDotGit = true

[Emin017]

Perhaps yosys-slang could also be added to Yosys’s allPlugins attribute set:

nixpkgs/pkgs/by-name/yo/yosys/package.nix

Lines 81 to 84 in b064e65

	allPlugins = {
	bluespec = yosys-bluespec;
	ghdl = yosys-ghdl;
	}

[luciengaitskell]

Rebased from master

[luciengaitskell]

@Emin017

Perhaps yosys-slang could also be added to Yosys’s allPlugins attribute set:

Happy to add it (just did). I was cautious because synlig, the existing SystemVerilog plugin, isn't in that list.

[luciengaitskell]

Bump to latest povik/yosys-slang@64b4461

[Emin017]

@Emin017

Perhaps yosys-slang could also be added to Yosys’s allPlugins attribute set:

Happy to add it (just did). I was cautious because synlig, the existing SystemVerilog plugin, isn't in that list.

@luciengaitskell #473242

[Emin017]

nixpkgs-review result

Generated using nixpkgs-review-gha

Command: nixpkgs-review pr 472800
Commit: 5e848add09d52da4f967d435e866c6335694c62f (subsequent changes)
Merge: d98524b88c8c31cab99166c1232c23f013fa7f04

Logs: https://github.com/Emin017/nixpkgs-review-gha/actions/runs/20895283307

---

x86_64-linux

❌ 1 package failed to build:

• yosys-slang

---

aarch64-linux

❌ 1 package failed to build:

• yosys-slang

---

aarch64-darwin (sandbox = true)

❌ 1 package failed to build:

• yosys-slang

[Emin017]

Still got hash mismatch:

Total 130 (delta 6), reused 123 (delta 0), pack-reused 0 (from 0)
Enumerating objects: 130, done.
Nothing new to pack.
error: hash mismatch in fixed-output derivation '/nix/store/pwlipqm4ykbd7zr3cly26xf5f0r8d78b-source.drv':
         specified: sha256-kfu59/M3+IM+5ZMd+Oy4IZf4JWuVtPDlkHprk0FB8t4=
            got:    sha256-5y1fQLXLUv9R98CVezYvPpxRSzJyeAKh8g++yTZVlgQ=
error: Cannot build '/nix/store/h1a9ivy7wqqzq67kqh5b2x7v97r0dw5h-yosys-slang-0-unstable-2025-12-15.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/248c0xdrwgihwj3qxvp32jcj1spvdkxy-yosys-slang-0-unstable-2025-12-15

https://github.com/NixOS/nixpkgs/pull/472800/checks?check_run_id=60026979158

[Emin017]

It looks like we’re running into some non-reproducible behavior — the hash values differ across machines in CI. https://github.com/Emin017/nixpkgs-review-gha/actions/runs/20895283307

[Emin017]

In yosys-slang, cmake/GitRevision.cmake runs git -C <dir> rev-parse HEAD to retrieve the commit IDs of both the main repository and third_party/slang. These values are used in src/CMakeLists.txt to generate version.h, which causes the hash of the build outputs to differ on every build.

I think we can remove the leaveDotGit = true option for now, so that the version information becomes unknown(But this can fix hash mismatch). After that, we may need to make some changes upstream to fix this generation issue properly.

@luciengaitskell Could you try removing the leaveDotGit = true option first?

[luciengaitskell]

@Emin017 I removed the leaveDotGit = true and set the YOSYS_SLANG_REVISION directly from the yosys-slang revision that we choose to fetch from GitHub.

However, the SLANG_REVISION would need to be determined based on the submodule, which I don't think I can get access to. @povik any ideas how we can get around this?

https://github.com/povik/yosys-slang/blob/64b44616a3798f07453b14ea03e4ac8a16b77313/src/CMakeLists.txt#L4-L5

[povik]

I suggest setting "SLANG_REVISION=unknown" for now. The only purpose of the version variables is to print the version to the user if they ask. In theory one can always find what the submodule version was from the yosys-slang revision.

[povik]

I see you are already setting it to unknown. I think that's fine.

[luciengaitskell]

Bump to latest povik/yosys-slang@4e1ad7c

[Emin017]

nixpkgs-review result

Generated using nixpkgs-review-gha

Command: nixpkgs-review pr 472800
Commit: ca571768fd58633b8400c227080dad000f8cbc53 (subsequent changes)
Merge: f93460ddf76ca4369cd52238bdf5b6ab175138f3

Logs: https://github.com/Emin017/nixpkgs-review-gha/actions/runs/21558626213

---

x86_64-linux

❌ 1 package failed to build:

• yosys-slang

---

aarch64-linux

❌ 1 package failed to build:

• yosys-slang

---

x86_64-darwin

✅ No rebuilds

---

aarch64-darwin (sandbox = relaxed)

❌ 1 package failed to build:

• yosys-slang

[Emin017]

The non-reproducible behavior has been fixed. We just need to update the hash and clean up some dead code.

[luciengaitskell]

Rebased from master

[Emin017]

nixpkgs-review result

Generated using nixpkgs-review-gha

Command: nixpkgs-review pr 472800
Commit: ca86215dbdf6ff26bd47b4fe5cdfc9967f870f65 (subsequent changes)
Merge: fd3863171a82fec7fa815f3497b7ae6892f10922

Logs: https://github.com/Emin017/nixpkgs-review-gha/actions/runs/21564372680

---

x86_64-linux

✅ 1 package built:

• yosys-slang

---

aarch64-linux

✅ 1 package built:

• yosys-slang

---

x86_64-darwin

✅ No rebuilds

---

aarch64-darwin (sandbox = relaxed)

✅ 1 package built:

• yosys-slang

[Emin017]

Approved automatically following the successful run of nixpkgs-review.