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stdenv: fix eval for native LLVM #463361

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stdenv: fix eval for native LLVM #463361

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@RossComputerGuy RossComputerGuy commented Nov 20, 2025

Things done

Fixes evaluation of:

(import nixpkgs {
  crossSystem = {
    system = "aarch64-linux";
    useLLVM = true;
  };
  localSystem = {
    system = "aarch64-linux";
    useLLVM = true;
  };
}).stdenv

This does not make it usable. Making it usable will be a follow up PR.

  • Built on platform:
    • x86_64-linux
    • aarch64-linux
    • x86_64-darwin
    • aarch64-darwin
  • Tested, as applicable:
  • 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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nixos-discourse commented Nov 20, 2025

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/adding-usellvm-to-a-nixos-system-flake/66487/2

@nixpkgs-ci nixpkgs-ci bot added 10.rebuild-linux: 501+ This PR causes many rebuilds on Linux and should normally target the staging branches. 10.rebuild-darwin: 501+ This PR causes many rebuilds on Darwin and should normally target the staging branches. 10.rebuild-darwin-stdenv This PR causes stdenv to rebuild on Darwin and must target a staging branch. 10.rebuild-darwin: 5001+ This PR causes many rebuilds on Darwin and must target the staging branches. 10.rebuild-linux: 1001-2500 This PR causes many rebuilds on Linux and should target the staging branches. 6.topic: stdenv Standard environment 6.topic: llvm/clang Issues related to llvmPackages, clangStdenv and related labels Nov 20, 2025
@RossComputerGuy RossComputerGuy marked this pull request as draft November 20, 2025 03:47
@RossComputerGuy RossComputerGuy changed the base branch from master to staging November 20, 2025 03:48
@RossComputerGuy RossComputerGuy marked this pull request as ready for review November 20, 2025 03:48
@nixpkgs-ci nixpkgs-ci bot closed this Nov 20, 2025
@nixpkgs-ci nixpkgs-ci bot reopened this Nov 20, 2025
@github-project-automation github-project-automation bot moved this to Done in Stdenv Nov 20, 2025
@RossComputerGuy RossComputerGuy moved this from Done to Todo in Stdenv Nov 20, 2025
alyssais
alyssais reviewed Nov 20, 2025
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pkgs/development/compilers/llvm/common/bintools.nix
runCommand "llvm-binutils-${version}"
{
pname = "llvm-binutils";
inherit version;
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@alyssais alyssais Nov 20, 2025

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What does this have to do with fixing eval?

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@RossComputerGuy RossComputerGuy Nov 20, 2025

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It makes the expression I mentioned actually evaluate.

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@alyssais alyssais Nov 20, 2025

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But why?

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@RossComputerGuy RossComputerGuy Nov 20, 2025

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Because the nixpkgs configuration fails here with missing attribute errors and it's needed for #463395

nixpkgs/pkgs/stdenv/linux/default.nix

Lines 559 to 560 in 411faf4

pname = prevStage.bintools.bintools.pname + "-patchelfed-ld";
inherit (prevStage.bintools.bintools) version;

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@alyssais alyssais Jan 27, 2026

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Could the commit message please explain that stdenv needs those attributes? Apart from that LGTM.

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@RossComputerGuy RossComputerGuy Jan 28, 2026

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Done

LordGrimmauld
LordGrimmauld reviewed Nov 23, 2025
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I can confirm this does fix eval. I am building my toy VM against this just to see how far i get. I don't feel confident approving this, stdenv is a bit out of my expertise, but this does look useful

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LordGrimmauld commented Nov 23, 2025

Interesting, while eval does succeed with this, pkgs.stdenv.cc still seems to be gcc.
image

So i guess "Making it usable will be a follow up PR." entails a bit more than just fixing eval.

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RossComputerGuy commented Nov 23, 2025

Yes, #463395 actually makes it possible. This PR just makes eval not broken. My idea is to have the native LLVM not cause any side effects so the eval fix is in its own PR.

@RossComputerGuy
llvmPackages.bintools: add pname and version
6f5150d 
Adds the pname & version since `pkgs/stdenv/linux/default.nix`
inherits the version & appends a string to the name.
@RossComputerGuy
pkgs/stdenv/linux/default.nix: force binutils
25908a8
alyssais
alyssais reviewed Jan 28, 2026
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pkgs/stdenv/linux/default.nix
installPhase = ''
mkdir -p "$out"/bin
cp -a '${prevStage.bintools.bintools}'/bin/* "$out"/bin/
cp -a '${prevStage.binutils.bintools}'/bin/* "$out"/bin/
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@alyssais alyssais Jan 28, 2026

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Won't this do the wrong thing when we're using LLVM bintools?

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@RossComputerGuy RossComputerGuy Jan 28, 2026

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Isn't binutils an alias for whatever linker is configured via linker in {local,cross}System?

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@alyssais alyssais Jan 28, 2026

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No, that's what bintools is. binutils is GNU binutils.

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Huh, I'll have to take a look at what I did. It might've been an infinite recursion thing. I'm traveling right now so I won't be able to look at it for some time.

@RossComputerGuy RossComputerGuy mentioned this pull request Feb 9, 2026
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@nixpkgs-ci nixpkgs-ci bot requested review from a team February 10, 2026 03:17
@jopejoe1 jopejoe1 mentioned this pull request Feb 12, 2026
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6.topic: llvm/clang Issues related to llvmPackages, clangStdenv and related 6.topic: stdenv Standard environment 10.rebuild-darwin: 501+ This PR causes many rebuilds on Darwin and should normally target the staging branches. 10.rebuild-darwin: 5001+ This PR causes many rebuilds on Darwin and must target the staging branches. 10.rebuild-darwin-stdenv This PR causes stdenv to rebuild on Darwin and must target a staging branch. 10.rebuild-linux: 501+ This PR causes many rebuilds on Linux and should normally target the staging branches. 10.rebuild-linux: 1001-2500 This PR causes many rebuilds on Linux and should target the staging branches.

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