{
  stdenv,
  lib,
  ninja,
  addDriverRunpath,
  cmake,
  emhash,
  fetchFromGitHub,
  khronos-ocl-icd-loader,
  libbacktrace,
  opencl-headers,
  parallel-hashmap,
  perl,
  pkg-config,
  python3,
  spirv-headers,
  spirv-tools,
  symlinkJoin,
  zlib,

  cudaPackages,
  enableCuda ? true,
}:

let
  version = "6.2.1";
  src = fetchFromGitHub {
    owner = "intel";
    repo = "llvm";
    tag = "v${version}";
    sha256 = "sha256-j8+DmGKO0qDF5JjH+DlkLKs1kBz6dS7ukwySd/Crqv0=";
  };

  pinned = {
    inherit parallel-hashmap;

    vc-intrinsics.src = fetchFromGitHub {
      owner = "intel";
      repo = "vc-intrinsics";
      rev = "4e51b2467104a257c22788e343dafbdde72e28bb";
      sha256 = "sha256-AHXeKbih4bzmcuu+tx2TeS7Ixmk54uS1vKFVxI6ZP8g=";
    };

    unified-memory-framework.src = fetchFromGitHub {
      owner = "oneapi-src";
      repo = "unified-memory-framework";
      tag = "v0.11.0";
      sha256 = "sha256-k8QdP2u1QOoeCZ6ps4sM8+1iZq/H3q0lqCfVk8mz9KI=";
    };

    ocl-headers = opencl-headers.overrideAttrs {
      version = "2024.10.24";
      src = fetchFromGitHub {
        owner = "KhronosGroup";
        repo = "OpenCL-Headers";
        tag = "v2024.10.24";
        sha256 = "sha256-KDlruE0IG8d+lAChxYyc6dg5XOvqCMrMyO69sdAzejA=";
      };
    };

    ocl-icd = khronos-ocl-icd-loader;

    spirv-headers = spirv-headers.overrideAttrs {
      version = "1.4.309.0";
      src = fetchFromGitHub {
        owner = "KhronosGroup";
        repo = "SPIRV-Headers";
        tag = "vulkan-sdk-1.4.309.0";
        sha256 = "sha256-Q1i6i5XimULuGufP6mimwDW674anAETUiIEvDQwvg5Y=";
      };
    };
  };

  fetchcontent_cmakeFlags = lib.mapAttrsToList (
    name: value: (lib.cmakeFeature "FETCHCONTENT_SOURCE_DIR_${lib.toUpper name}" (toString value.src))
  ) pinned;

  # Hack to fix #include <emhash/...>
  emhash' = symlinkJoin {
    name = "emhash";
    paths = [ emhash ];
    postBuild = ''
      pushd $out/include
      ln -s . emhash
      popd
    '';
  };

in
stdenv.mkDerivation {
  pname = "intel-llvm";
  inherit src version;

  enableParallelBuilding = true;
  strictDeps = true;

  nativeBuildInputs = [
    perl
    cmake
    ninja
    pkg-config
    python3
    spirv-tools
    addDriverRunpath
  ]
  ++ lib.optionals enableCuda [
    cudaPackages.cuda_nvcc
  ];

  buildInputs = [
    emhash'
    libbacktrace
    zlib

    pinned.ocl-icd
    pinned.ocl-headers
    pinned.spirv-headers
  ]
  ++ lib.optionals enableCuda [
    cudaPackages.cudatoolkit
  ];

  patches = [ ./fix-ur.patch ]; # Has been fixed in next release

  preBuild = ''
    chmod -R u+w /build/source
  '';

  cmakeDir = "../llvm";

  cmakeFlags =
    let
      cmakeList = name: l: lib.cmakeOptionType "list" name (builtins.concatStringsSep ";" l);

      LLVM_EXTERNAL_PROJECTS = [
        "sycl"
        "llvm-spirv"
        "opencl"
        "xpti"
        "xptifw"
        "compiler-rt"
        "sycl-jit"
      ]
      ++ lib.optionals enableCuda [
        "libclc"
      ];
    in
    [
      (lib.cmakeBool "LLVM_ENABLE_ASSERTIONS" true)

      (cmakeList "LLVM_TARGETS_TO_BUILD" (
        [
          "host"
          "SPIRV"
        ]
        ++ lib.optionals enableCuda [ "NVPTX" ]
      ))
      (cmakeList "LLVM_EXTERNAL_PROJECTS" LLVM_EXTERNAL_PROJECTS)
      (cmakeList "LLVM_ENABLE_PROJECTS" ([ "clang" ] ++ LLVM_EXTERNAL_PROJECTS))

      (lib.cmakeBool "UR_USE_EXTERNAL_UMF" false)
      (lib.cmakeOptionType "path" "UR_OPENCL_INCLUDE_DIR" (toString pinned.ocl-headers))
      (lib.cmakeOptionType "path" "UR_OPENCL_ICD_LOADER_LIBRARY" (toString pinned.ocl-icd))
      (lib.cmakeFeature "UR_OPENCL_ICD_LOADER_LIBRARY" (toString pinned.ocl-icd))

      (lib.cmakeBool "BUILD_SHARED_LIBS" false)
      (lib.cmakeBool "LLVM_BUILD_TOOLS" true)
      (lib.cmakeBool "LLVM_ENABLE_ZSTD" true)
      (lib.cmakeBool "LLVM_USE_STATIC_ZSTD" true)
      (lib.cmakeBool "LLVM_ENABLE_DOXYGEN" false)
      (lib.cmakeBool "LLVM_ENABLE_LLD" false)
      (lib.cmakeBool "LLVM_ENABLE_SPHINX" false)
      (lib.cmakeBool "LLVM_SPIRV_ENABLE_LIBSPIRV_DIS" false)
      (lib.cmakeBool "SYCL_ENABLE_WERROR" false)
      (lib.cmakeBool "SYCL_INCLUDE_TESTS" false)
      (lib.cmakeBool "SYCL_ENABLE_EXTENSION_JIT" true)
      (lib.cmakeBool "SYCL_ENABLE_MAJOR_RELEASE_PREVIEW_LIB" false)
      (lib.cmakeBool "SYCL_ENABLE_XPTI_TRACING" true)
      (lib.cmakeBool "XPTI_ENABLE_WERROR" false)

      (cmakeList "SYCL_ENABLE_BACKENDS" ([ "opencl" ] ++ lib.optionals enableCuda [ "cuda" ]))
    ]
    ++ fetchcontent_cmakeFlags
    ++ lib.optionals enableCuda [
      (lib.cmakeOptionType "list" "LIBCLC_TARGETS_TO_BUILD" "nvptx64--nvidiacl")
      (lib.cmakeBool "LIBCLC_GENERATE_REMANGLED_VARIANTS" true)
      (lib.cmakeBool "LIBCLC_NATIVECPU_HOST_TARGET" false)
    ];

  meta = {
    homepage = "https://github.com/intel/llvm";
    description = "Intel staging area for llvm.org contribution";
    maintainers = with lib.maintainers.bsc; [ abonerib ];
    platforms = lib.platforms.linux;
    license = [
      lib.licenses.asl20
      lib.licenses.llvm-exception
    ];
  };
}