depot/third_party/nixpkgs/pkgs/development/compilers/cudatoolkit/extension.nix

final: prev: let
  ### Cuda Toolkit

  # Function to build the class cudatoolkit package
  buildCudaToolkitPackage = final.callPackage ./common.nix;

  # Version info for the classic cudatoolkit packages that contain everything that is in redist.
  cudatoolkitVersions = final.lib.importTOML ./versions.toml;

  finalVersion = cudatoolkitVersions.${final.cudaVersion};

  # Exposed as cudaPackages.backendStdenv.
  # We don't call it just "stdenv" to avoid confusion: e.g. this toolchain doesn't contain nvcc.
  # Instead, it's the back-end toolchain for nvcc to use.
  # We also use this to link a compatible libstdc++ (backendStdenv.cc.cc.lib)
  # Cf. https://github.com/NixOS/nixpkgs/pull/218265 for context
  backendStdenv = prev.pkgs."${finalVersion.gcc}Stdenv";

  ### Add classic cudatoolkit package
  cudatoolkit =
    let
      attrs = builtins.removeAttrs finalVersion [ "gcc" ];
      attrs' = attrs // { inherit backendStdenv; };
    in
    buildCudaToolkitPackage attrs';

  cudaFlags = final.callPackage ./flags.nix {};

in
{
  inherit
    backendStdenv
    cudatoolkit
    cudaFlags;
}