cudaPackages.backendStdenv: use gccForLibs

  stdenv,

  wrapCCWith,

}:

let

  gccMajorVersion = nvccCompatibilities.${cudaVersion}.gccMaxMajorVersion;

  # We use buildPackages (= pkgsBuildHost) because we look for a gcc that

  # The target platform of buildPackages.gcc is our host platform, so its

  # .lib output should be the libstdc++ we want to be writing in the runpaths

  # Cf. https://github.com/NixOS/nixpkgs/pull/225661#discussion_r1164564576

  nixpkgsCompatibleLibstdcxx = buildPackages.gcc.cc.lib;

  ccForLibs = stdenv.cc.cc;

  cxxStdlib = lib.getLib ccForLibs;

  nvccCompatibleCC = buildPackages."gcc${gccMajorVersion}".cc;

  cc = wrapCCWith {

    cc = nvccCompatibleCC;

    # This option is for clang's libcxx, but we (ab)use it for gcc's libstdc++.

    # Note that libstdc++ maintains forward-compatibility: if we load a newer

    # libstdc++ into the process, we can still use libraries built against an

    # older libstdc++. This, in practice, means that we should use libstdc++ from

    # the same stdenv that the rest of nixpkgs uses.

    # We currently do not try to support anything other than gcc and linux.

    libcxx = nixpkgsCompatibleLibstdcxx;

    # Note: normally the `useCcForLibs`/`gccForLibs` mechanism is used to get a

    # clang based `cc` to use `libstdc++` (from gcc).

    # Here we (ab)use it to use a `libstdc++` from a different `gcc` than our

    # `cc`.

    # Note that this does not inhibit our `cc`'s lib dir from being added to

    # cflags/ldflags (see `cc_solib` in `cc-wrapper`) but this is okay: our

    # `gccForLibs`'s paths should take precedence.

    useCcForLibs = true;

    gccForLibs = ccForLibs;

  };

  cudaStdenv = overrideCC stdenv cc;

  passthruExtra = {

    inherit nixpkgsCompatibleLibstdcxx;

    nixpkgsCompatibleLibstdcxx = lib.warn "cudaPackages.backendStdenv.nixpkgsCompatibleLibstdcxx is misnamed, deprecated, and will be removed after 24.05" cxxStdlib;

    # cc already exposed

  };

  assertCondition = true;

in

# We should use libstdc++ at least as new as nixpkgs' stdenv's one.

assert ((stdenv.cc.cxxStdlib.kind or null) == "libstdc++")

  -> lib.versionAtLeast cxxStdlib.version stdenv.cc.cxxStdlib.lib.version;

lib.extendDerivation assertCondition passthruExtra cudaStdenv

      #    loading multiple extensions in the same python program due to duplicate protobuf DBs.

      # 2) Patch python path in the compiler driver.

      preBuild = lib.optionalString cudaSupport ''

        export NIX_LDFLAGS+=" -L${backendStdenv.nixpkgsCompatibleLibstdcxx}/lib"

        patchShebangs ../output/external/xla/third_party/gpus/crosstool/clang/bin/crosstool_wrapper_driver_is_not_gcc.tpl

      '' + lib.optionalString stdenv.isDarwin ''

        # Framework search paths aren't added by bintools hook