OneAPI whisper.cpp ongoing in-development build process

flake.nix

# OneAPI whisper.cpp ongoing in-development build process
# devShell works(with FHS), `$ nix run .` doesn't work yet, needs OneAPI on nixpkgs/derivation.
{
  description = "Development environment for whisper.cpp with Intel compilers and SYCL";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    flake-utils.url = "github:numtide/flake-utils";
  };

  outputs = { self, nixpkgs, flake-utils }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = nixpkgs.legacyPackages.${system};

        getAllPkgConfigPaths = pkgs: inputs:
          let
            allDeps = pkgs.lib.closePropagation inputs;
          in
          pkgs.lib.makeSearchPathOutput "out" "lib/pkgconfig" allDeps + ":" +
          pkgs.lib.makeSearchPathOutput "out" "share/pkgconfig" allDeps + ":" +
          pkgs.lib.makeSearchPathOutput "dev" "lib/pkgconfig" allDeps + ":" +
          pkgs.lib.makeSearchPathOutput "dev" "share/pkgconfig" allDeps;

        FHSTargetPkgs = with pkgs; [
          glibc.dev # NOTE: Required: #include <stdio.h>
          gcc-unwrapped # NOTE: essential! for pass binutils-2.44/bin/ld: cannot find crtbegin.o: No such file or directory
          zlib # NOTE: loading shared libraries: libz.so
          # intel-compute-runtime.drivers # NOTE: Good addition to expose the driver for CI
          level-zero  # NOTE: Required: Intel GPU driver interface
          SDL2 # NOTE: Required dependency
        ];

        fhsEnv = pkgs.buildFHSEnv rec {
          name = "whisper-cpp-dev";
          
          targetPkgs = pkgs: (with pkgs; FHSTargetPkgs);
          
          profile = ''
            export LANG=C.UTF-8
            export LC_ALL=C.UTF-8
            export ONEAPI_ROOT="$HOME/intel/oneapi" # Intel compiler paths (adjust these to your installation)

            # export LIBRARY_PATH="${pkgs.lib.makeLibraryPath FHSTargetPkgs}:$LIBRARY_PATH"
            # export LD_LIBRARY_PATH="${pkgs.lib.makeLibraryPath FHSTargetPkgs}:$LD_LIBRARY_PATH"
            # The order matters - system headers should come last:
            # export CPATH="${pkgs.lib.makeIncludePath FHSTargetPkgs}:$CPATH" # add :$CPATH
            # export C_INCLUDE_PATH="${pkgs.lib.makeIncludePath FHSTargetPkgs}:$C_INCLUDE_PATH"
            # export CPLUS_INCLUDE_PATH="${pkgs.lib.makeIncludePath FHSTargetPkgs}:$CPLUS_INCLUDE_PATH" # NOTE: used by whisper.cpp
            
            # Setup OpenVINO after setting up basic environment
            source ${pkgs.openvino}/setupvars.sh 2>/dev/null || echo "OpenVINO setup completed with warnings"
            
            if [ -d "$ONEAPI_ROOT" ]; then
              source "$ONEAPI_ROOT/setvars.sh" --force 2>/dev/null || true
            fi
            
            export CC=icx
            export CXX=icpx

            echo "🚀 Entering whisper.cpp development environment with Intel compilers"
            echo "📍 Intel OneAPI root: $ONEAPI_ROOT"
            echo "🔧 CC=$CC, CXX=$CXX"
          '';

          runScript = "zsh";
        };
      in
      {
        devShells.default = pkgs.mkShell rec {
          name = "whisper-cpp-fhs-dev";
          
          buildInputs = FHSTargetPkgs ++ [ fhsEnv ];

          PKG_CONFIG_PATH = getAllPkgConfigPaths pkgs (buildInputs);
          
          shellHook = ''
            echo "🔄 Setting up FHS environment for whisper.cpp development..."
            echo "🏗️  This will provide a standard Linux environment for Intel compilers"
            echo "To enter the FHS environment, run:"
            echo "  whisper-cpp-dev"

            echo "🚀 Auto-entering FHS environment..."
            exec whisper-cpp-dev
          ''; # Shell hook that runs before entering FHS
        };
        
        devShells.manual = pkgs.mkShell {
          name = "whisper-cpp-manual";
          
          buildInputs = [ fhsEnv ];
          
          shellHook = ''
            echo "🔧 Manual FHS environment ready"
            echo "Run 'whisper-cpp-dev' to enter FHS environment"
            echo "Current directory: $(pwd)"
            # Set up any non-FHS environment variables here
          ''; # Alternative: Manual FHS shell (doesn't auto-enter)
        };
        
        # TODO: Make this work still, it tells me icx not found, maybe add direct FHS environment (for `nix run`)
        packages.default = pkgs.stdenv.mkDerivation rec {
          pname = "whisper-cli";
          version = "unstable";

          src = ./.;

          nativeBuildInputs = with pkgs; [
            cmake
            ninja
            pkg-config
            SDL2
            zlib
          ];

          buildInputs = with pkgs; [
            SDL2
            zlib
            level-zero
          ];

          ONEAPI_ROOT = "${builtins.getEnv "HOME"}/intel/oneapi"; # Today, unfortunately, you must still install oneAPI separately.

          cmakeFlags = [
            "-DWHISPER_SDL2=ON"
            "-DWHISPER_OPENVINO=1"
            "-DGGML_SYCL=ON"
            "-DCMAKE_C_COMPILER=/home/izelnakri/intel/oneapi/compiler/latest/bin/icx"
            "-DCMAKE_CXX_COMPILER=/home/izelnakri/intel/oneapi/compiler/latest/bin/icpx"
          ];

          # TODO: Issue is there is NO ONEAPI on the sandbox environment, that needs to change
          configurePhase = ''
            export ONEAPI_ROOT="/home/izelnakri/intel/oneapi" # TODO: Make this in the FUTURE(not now) ~/ or $HOME
            export PATH="$ONEAPI_ROOT/compiler/latest/bin:$PATH"
            export LD_LIBRARY_PATH="$ONEAPI_ROOT/compiler/latest/lib:$LD_LIBRARY_PATH"

            echo "IZELL"
            source ${pkgs.openvino}/setupvars.sh 2>/dev/null || echo "OpenVINO setup completed with warnings"
            [ -d "$ONEAPI_ROOT" ] && source "$ONEAPI_ROOT/setvars.sh" --force 2>/dev/null || true

            export CC="$ONEAPI_ROOT/compiler/latest/bin/icx"
            export CXX="$ONEAPI_ROOT/compiler/latest/bin/icpx"
            export CMAKE_C_COMPILER="$ONEAPI_ROOT/compiler/latest/bin/icx"
            export CMAKE_CXX_COMPILER="$ONEAPI_ROOT/compiler/latest/bin/icpx"

            echo "IZELL FINISH"
            echo $(command -v icx)
            echo "PATH IS"
            echo $PATH
            echo $CMAKE_C_COMPILER
            echo $CMAKE_CXX_COMPILER

            mkdir -p build
            cd build

            cmake .. -G Ninja ${pkgs.lib.strings.concatStringsSep " " cmakeFlags}
          '';

          buildPhase = ''
            echo "IZELL STARTED BUILD PHASE"
            echo $(command -v icx)
            echo $PATH
            cd build
            ninja
          '';

          installPhase = ''
            mkdir -p $out/bin
            cp build/bin/whisper-cli $out/bin/
          '';
        };
        
        apps.default = {
          type = "app";
          program = "${self.packages.${system}.default}/bin/whisper-cli";
        };
      });
}