Add TACUDA through cudaPackages extensions

overlay.nix

@@ -51,6 +51,7 @@ let
     ovniGit = final.ovni.override { useGit = true; };
     paraverKernel = callPackage ./pkgs/paraver/kernel.nix { };
     pocl = callPackage ./pkgs/pocl/default.nix { };
+    pocl-noicd = callPackage ./pkgs/pocl/default.nix { enableICD = false; };
     prometheus-slurm-exporter = prev.callPackage ./pkgs/slurm-exporter/default.nix { };
     #pscom = callPackage ./pkgs/parastation/pscom.nix { }; # Unmaintaned
     #psmpi = callPackage ./pkgs/parastation/psmpi.nix { }; # Unmaintaned
@@ -63,7 +64,16 @@ let
     tagaspi = callPackage ./pkgs/tagaspi/default.nix { };
     tampi = callPackage ./pkgs/tampi/default.nix { };
     upc-qaire-exporter = prev.callPackage ./pkgs/upc-qaire-exporter/default.nix { };
+    taopencl = callPackage ./pkgs/taopencl/default.nix { };
     wxparaver = callPackage ./pkgs/paraver/default.nix { };
+
+    gromacs = callPackage ./pkgs/gromacs/default.nix { enableSYCL = true; };
+
+    _cuda = prev._cuda.extend (_: _prev: final.lib.recursiveUpdate _prev {
+      extensions = _prev.extensions ++ [(finalAttrs: _: {
+        tacuda = finalAttrs.callPackage ./pkgs/tacuda/default.nix { };
+      })];
+    });
   };
 
   tests = rec {
@@ -98,7 +108,12 @@ let
       stdenv = final.stdenvClangOmpss2NodesOmpv;
     };
 
+    ocl-build = callPackage ./test/compilers/opencl.nix { };
+    ocl-build-noicd = callPackage ./test/compilers/opencl.nix { ocl-icd = final.pocl-noicd; };
+
     pocl = callPackage ./test/compilers/pocl.nix { };
+    ocl-run-pocl = ocl-build.test-icd;
+    ocl-run-pocl-noicd = ocl-build-noicd.test-noicd;
   };
 
   # For now, only build toplevel packages in CI/Hydra

pkgs/gromacs/default.nix

@@ -0,0 +1,190 @@
+{
+  lib,
+  stdenv,
+  fetchurl,
+  cmake,
+  hwloc,
+  fftw,
+  perl,
+  blas,
+  lapack,
+  llvmPackages,
+  intelPackages ? null,
+  mpi,
+  cudaPackages,
+  plumed,
+  singlePrec ? true,
+  config,
+  enableSYCL ? false,
+  enableCuda ? config.cudaSupport,
+  enableMpi ? false,
+  enablePlumed ? false,
+  cpuAcceleration ? null,
+}:
+
+# CUDA is only implemented for single precission
+assert enableCuda -> singlePrec;
+
+assert !(enableSYCL && enableCuda);
+
+assert enableSYCL -> intelPackages != null;
+
+let
+  inherit (cudaPackages.flags) cmakeCudaArchitecturesString;
+
+  # Select reasonable defaults for all major platforms
+  # The possible values are defined in CMakeLists.txt:
+  # AUTO None SSE2 SSE4.1 AVX_128_FMA AVX_256 AVX2_256
+  # AVX2_128 AVX_512 AVX_512_KNL MIC ARM_NEON ARM_NEON_ASIMD
+  SIMD =
+    x:
+    if (cpuAcceleration != null) then
+      x
+    else if stdenv.hostPlatform.system == "i686-linux" then
+      "SSE2"
+    else if stdenv.hostPlatform.system == "x86_64-linux" then
+      "SSE4.1"
+    else if stdenv.hostPlatform.system == "x86_64-darwin" then
+      "SSE4.1"
+    else if stdenv.hostPlatform.system == "aarch64-linux" then
+      "ARM_NEON_ASIMD"
+    else
+      "None";
+
+  source =
+    if enablePlumed then
+      {
+        version = "2024.2";
+        hash = "sha256-gCp+M18uiVdw9XsVnk7DaOuw/yzm2sz3BsboAlw2hSs=";
+      }
+    else
+      {
+        version = "2025.3";
+        hash = "sha256-i9/KAmjz8Qp8o8BuWbYvc+oCQgxnIRwP85EvMteDPGU=";
+      };
+
+  stdenv' = if enableSYCL then intelPackages.stdenv else stdenv;
+
+in
+stdenv'.mkDerivation rec {
+  pname = "gromacs";
+  version = source.version;
+
+  src = fetchurl {
+    url = "ftp://ftp.gromacs.org/pub/gromacs/gromacs-${version}.tar.gz";
+    inherit (source) hash;
+  };
+
+  patches = [ (if enablePlumed then ./pkgconfig-2024.patch else ./pkgconfig-2025.patch) ];
+
+  postPatch = lib.optionalString enablePlumed ''
+    plumed patch -p -e gromacs-${source.version}
+  '';
+
+  outputs = [
+    "out"
+    "dev"
+    "man"
+  ];
+
+  nativeBuildInputs = [
+    cmake
+  ]
+  ++ lib.optional enablePlumed plumed
+  ++ lib.optionals enableCuda [ cudaPackages.cuda_nvcc ];
+
+  env.MKLROOT = intelPackages.mkl;
+
+  buildInputs = [
+    fftw
+    perl
+    hwloc
+    blas
+    lapack
+  ]
+  ++ lib.optional enableMpi mpi
+  ++ lib.optionals enableCuda [
+    cudaPackages.cuda_cccl
+    cudaPackages.cuda_cudart
+    cudaPackages.libcufft
+    cudaPackages.cuda_profiler_api
+  ]
+  ++ lib.optional stdenv.hostPlatform.isDarwin llvmPackages.openmp;
+
+  propagatedBuildInputs = lib.optional enableMpi mpi;
+  propagatedUserEnvPkgs = lib.optional enableMpi mpi;
+
+  cmakeFlags = [
+    (lib.cmakeBool "GMX_HWLOC" true)
+    "-DGMX_SIMD:STRING=${SIMD cpuAcceleration}"
+    "-DGMX_OPENMP:BOOL=TRUE"
+    "-DBUILD_SHARED_LIBS=ON"
+  ]
+  ++ (
+    if singlePrec then
+      [
+        "-DGMX_DOUBLE=OFF"
+      ]
+    else
+      [
+        "-DGMX_DOUBLE=ON"
+        "-DGMX_DEFAULT_SUFFIX=OFF"
+      ]
+  )
+  ++ (
+    if enableMpi then
+      [
+        "-DGMX_MPI:BOOL=TRUE"
+        "-DGMX_THREAD_MPI:BOOL=FALSE"
+      ]
+    else
+      [
+        "-DGMX_MPI:BOOL=FALSE"
+      ]
+  )
+  ++ (lib.optionals enableSYCL [
+    "-DGMX_GPU=SYCL"
+    "-DGMX_OPENMP=OFF" # TODO: enable OpenMP with SYCL?
+  ])
+  ++ lib.optionals enableCuda [
+    "-DGMX_GPU=CUDA"
+    (lib.cmakeFeature "CMAKE_CUDA_ARCHITECTURES" cmakeCudaArchitecturesString)
+
+    # Gromacs seems to ignore and override the normal variables, so we add this ad hoc:
+    (lib.cmakeFeature "GMX_CUDA_TARGET_COMPUTE" cmakeCudaArchitecturesString)
+  ];
+
+  postInstall = ''
+    moveToOutput share/cmake $dev
+  '';
+
+  meta = with lib; {
+    homepage = "https://www.gromacs.org";
+    license = licenses.lgpl21Plus;
+    description = "Molecular dynamics software package";
+    longDescription = ''
+      GROMACS is a versatile package to perform molecular dynamics,
+      i.e. simulate the Newtonian equations of motion for systems
+      with hundreds to millions of particles.
+
+      It is primarily designed for biochemical molecules like
+      proteins, lipids and nucleic acids that have a lot of
+      complicated bonded interactions, but since GROMACS is
+      extremely fast at calculating the nonbonded interactions (that
+      usually dominate simulations) many groups are also using it
+      for research on non-biological systems, e.g. polymers.
+
+      GROMACS supports all the usual algorithms you expect from a
+      modern molecular dynamics implementation, (check the online
+      reference or manual for details), but there are also quite a
+      few features that make it stand out from the competition.
+
+      See: https://www.gromacs.org/about.html for details.
+    '';
+    platforms = platforms.unix;
+    maintainers = with maintainers; [
+      sheepforce
+      markuskowa
+    ];
+  };
+}

pkgs/gromacs/pkgconfig-2024.patch

@@ -0,0 +1,24 @@
+diff --git a/src/external/muparser/muparser.pc.in b/src/external/muparser/muparser.pc.in
+index 646787cb53..9b97ad57f7 100644
+--- a/src/external/muparser/muparser.pc.in
++++ b/src/external/muparser/muparser.pc.in
+@@ -1,7 +1,5 @@
+-prefix=@CMAKE_INSTALL_PREFIX@
+-exec_prefix=${prefix}
+-libdir=${prefix}/@CMAKE_INSTALL_LIBDIR@
+-includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
++libdir=@CMAKE_INSTALL_FULL_LIBDIR@
++includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@
+ 
+ Name: @PACKAGE_NAME@
+ Description: Mathematical expressions parser library
+diff --git a/src/gromacs/libgromacs.pc.cmakein b/src/gromacs/libgromacs.pc.cmakein
+index ec1ed6684e..ca1105474a 100644
+--- a/src/gromacs/libgromacs.pc.cmakein
++++ b/src/gromacs/libgromacs.pc.cmakein
+@@ -1,4 +1,4 @@
+-libdir=@CMAKE_INSTALL_PREFIX@/@CMAKE_INSTALL_LIBDIR@
++libdir=@CMAKE_INSTALL_FULL_LIBDIR@
+ 
+ Name: libgromacs@GMX_LIBS_SUFFIX@
+ Description: Gromacs library

pkgs/gromacs/pkgconfig-2025.patch

@@ -0,0 +1,36 @@
+diff --git a/src/external/muparser/muparser.pc.in b/src/external/muparser/muparser.pc.in
+index 646787cb53..d26e84de8f 100644
+--- a/src/external/muparser/muparser.pc.in
++++ b/src/external/muparser/muparser.pc.in
+@@ -1,11 +1,9 @@
+-prefix=@CMAKE_INSTALL_PREFIX@
+-exec_prefix=${prefix}
+-libdir=${prefix}/@CMAKE_INSTALL_LIBDIR@
+-includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+-
+-Name: @PACKAGE_NAME@
+-Description: Mathematical expressions parser library
+-Version: @MUPARSER_VERSION@
+-Requires:
+-Libs: -L${libdir} -lmuparser
+-Cflags: -I${includedir} @PKG_CONFIG_FLAGS@
++libdir=@CMAKE_INSTALL_FULL_LIBDIR@
++includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@
++
++Name: @PACKAGE_NAME@
++Description: Mathematical expressions parser library
++Version: @MUPARSER_VERSION@
++Requires:
++Libs: -L${libdir} -lmuparser
++Cflags: -I${includedir} @PKG_CONFIG_FLAGS@
+diff --git a/src/gromacs/libgromacs.pc.cmakein b/src/gromacs/libgromacs.pc.cmakein
+index af9b5a6dc0..5f58d549bf 100644
+--- a/src/gromacs/libgromacs.pc.cmakein
++++ b/src/gromacs/libgromacs.pc.cmakein
+@@ -1,5 +1,4 @@
+-prefix=@CMAKE_INSTALL_PREFIX@
+-libdir=${prefix}/@CMAKE_INSTALL_LIBDIR@
++libdir=@CMAKE_INSTALL_FULL_LIBDIR@
+
+ Name: libgromacs@GMX_LIBS_SUFFIX@
+ Description: Gromacs library

pkgs/pocl/default.nix

@@ -13,6 +13,9 @@
   libxml2, # required for statically linked llvm
   python3,
   writableTmpDirAsHomeHook,
+  writeText,
+  runCommand,
+  opencl-cts,
 
   fetchFromGitHub,
 
@@ -194,22 +197,46 @@ stdenv.mkDerivation (finalAttrs: {
     runHook postInstallCheck
   '';
 
-  setupHook = ./setup-hook.sh;
+  setupHook = lib.optionalDrvAttr enableICD (
+    writeText "setup-hook" ''
+      addToSearchPath OCL_ICD_VENDORS @out@/etc/OpenCL/vendors
+    ''
+  );
 
-  passthru = {
-    updateScript = nix-update-script { };
-    git = finalAttrs.finalPackage.override { useGit = true; };
-    test = finalAttrs.finalPackage.overrideAttrs { doCheck = true; };
-  };
+  passthru =
+    let
+      self = finalAttrs.finalPackage;
+    in
+    {
+      updateScript = nix-update-script { };
+      git = self.override { useGit = true; };
 
-  requiredSystemFeatures = lib.optionals (finalAttrs.finalPackage.doCheck && enableHWLOC) [
-    "sys-devices"
-  ];
+      withICD = enableICD;
 
-  preCheck = ''
-    export POCL_DEBUG=error,warn
-    export NIX_DEBUG=1
-  '';
+      test = {
+        # Run builtin tests (causes a rebuild)
+        self = self.overrideAttrs { doCheck = true; };
+
+        # Run basic test from Khronos OpenCL Conformance Test Suite
+        # WARN: despite its name, test_basic is very exhaustive, and can take more
+        # than 1 hour in a marenostrum5 node.
+        cts =
+          assert enableICD;
+          lib.genAttrs [ "api" "basic" "c11_atomics" "printf" "svm" ] (
+            name:
+            runCommand "pocl-cts-test_${name}" {
+              nativeBuildInputs = [ self ];
+              requiredSystemFeatures = [ "sys-devices" ];
+              env = {
+                POCL_DEBUG = "error,warn";
+                POCL_CACHE_DIR = "/build/pocl_cache";
+              };
+            } "${opencl-cts}/bin/Release/test_${name} | tee $out"
+          );
+      };
+    };
+
+  env.HWLOC_SYNTHETIC = lib.optionalDrvAttr enableHWLOC "node:1 core:1 pu:1";
 
   propagatedBuildInputs = [ stdenv.cc.cc ];
 

pkgs/pocl/setup-hook.sh

@@ -1,6 +0,0 @@
-preCheckHooks+=('setupPoclCheck')
-preInstallCheckHooks+=('setupPoclCheck')
-
-setupPoclCheck () {
-  export OCL_ICD_VENDORS="@out@/etc/OpenCL/vendors"
-}

pkgs/tacuda/default.nix

@@ -0,0 +1,72 @@
+{
+  backendStdenv,
+  fetchFromGitHub,
+  automake,
+  autoconf,
+  libtool,
+  gnumake,
+  autoreconfHook,
+  boost,
+  cudatoolkit,
+  libcublas,
+  cuda_cudart,
+
+  useGit ? false,
+  gitUrl ? "git@gitlab-internal.bsc.es:task-awareness/tacuda/tacuda.git",
+  gitBranch ? "main",
+  gitCommit ? "35234f9445e6149a2bd38d119841e2485d6ee05e",
+}:
+
+let
+
+  release_ver = "2.1.0";
+  release = {
+    version = release_ver;
+    src = fetchFromGitHub {
+      owner = "bsc-pm";
+      repo = "tacuda";
+      rev = release_ver;
+      hash = "sha256-Cj3EiLVJSLvRv0ydeg7Vp4SpkniEqHkcWF+YOJQ8EcM=";
+    };
+  };
+
+  git = rec {
+    version = src.shortRev;
+    src = builtins.fetchGit {
+      url = gitUrl;
+      ref = gitBranch;
+      rev = gitCommit;
+    };
+  };
+
+  source = if (useGit) then git else release;
+
+in
+
+backendStdenv.mkDerivation {
+  pname = "tacuda";
+  inherit (source) src version;
+
+  enableParallelBuilding = true;
+  separateDebugInfo = true;
+  strictDeps = true;
+
+  nativeBuildInputs = [
+    autoreconfHook
+    automake
+    autoconf
+    libtool
+    gnumake
+  ];
+
+  patches = [ ./fix_config.patch ];
+
+  configureFlags = [ "--with-cuda-include=${cudatoolkit}/include" ];
+
+  buildInputs = [
+    boost
+    libcublas
+    cuda_cudart
+  ];
+
+}

pkgs/tacuda/fix_config.patch

@@ -0,0 +1,13 @@
+diff --git a/m4/cuda.m4 b/m4/cuda.m4
+index 23f5c94..8f9b534 100644
+--- a/m4/cuda.m4
++++ b/m4/cuda.m4
+@@ -40,7 +40,7 @@ search_libs="cuda cublas cudart"
+ required_libs=""
+ 
+ m4_foreach([function],
+-           [cuInit,
++           [
+ 	    cublasSgemm,
+             cudaStreamCreate,
+             cudaLaunchKernel,

pkgs/taopencl/default.nix

@@ -0,0 +1,46 @@
+{
+  stdenv,
+  automake,
+  autoconf,
+  libtool,
+  gnumake,
+  boost,
+  mpi,
+  gcc,
+  autoreconfHook,
+  ocl-icd,
+  opencl-headers,
+}:
+
+stdenv.mkDerivation (finalAttrs: {
+  pname = "taopencl";
+  version = finalAttrs.src.shortRev;
+
+  src = builtins.fetchGit {
+    url = "git@gitlab-internal.bsc.es:task-awareness/taopencl/taopencl.git";
+    ref = "master";
+    rev = "c3b7b32ae8fa4af7ceff598532a881f8f1490aaf";
+  };
+
+  enableParallelBuilding = true;
+  separateDebugInfo = true;
+
+  configureFlags = [
+    "--with-opencl-lib=${ocl-icd}/lib"
+    "--with-opencl-include=${opencl-headers}/include"
+  ];
+
+  buildInputs = [
+    autoreconfHook
+    automake
+    autoconf
+    libtool
+    gnumake
+    boost
+    mpi
+    gcc
+  ];
+
+  dontDisableStatic = true;
+  hardeningDisable = [ "all" ];
+})

test/compilers/opencl.c

@@ -0,0 +1,127 @@
+#include <CL/cl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define BUF_LEN 128
+
+cl_int exit_err = CL_SUCCESS;
+
+#define CHECK(cmd)                                                             \
+  do {                                                                         \
+    cl_int err = cmd;                                                          \
+    if (err != CL_SUCCESS) {                                                   \
+      printf("[ERROR] " #cmd " (Error code: %d)\n"                             \
+             "@ "__FILE__                                                      \
+             ":%d",                                                            \
+             err, __LINE__);                                                   \
+      exit_err = err;                                                          \
+      goto cleanup;                                                            \
+    }                                                                          \
+  } while (0)
+
+const char *kernel_source = "__kernel void vector_add(__global const float *a, "
+                            "__global const float *b, __global float *c) {\n"
+                            "    int gid = get_global_id(0);\n"
+                            "    c[gid] = a[gid] + b[gid];\n"
+                            "}\n";
+
+cl_int test_kernel_compilation(cl_platform_id platform) {
+  cl_device_id device = NULL;
+  cl_context context = NULL;
+  cl_program program = NULL;
+  cl_int err = CL_SUCCESS;
+  char device_name[BUF_LEN];
+
+  // Get first device for this platform
+  CHECK(clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, 1, &device, NULL));
+
+  // Get device name
+  CHECK(clGetDeviceInfo(device, CL_DEVICE_NAME, sizeof(device_name),
+                        device_name, NULL));
+  printf("    Device: %s\n", device_name);
+
+  context = clCreateContext(NULL, 1, &device, NULL, NULL, &err);
+  CHECK(err);
+
+  program = clCreateProgramWithSource(context, 1, &kernel_source, NULL, &err);
+  CHECK(err);
+
+  err = clBuildProgram(program, 1, &device, NULL, NULL, NULL);
+  if (err != CL_SUCCESS) {
+    printf("      [ERROR] Kernel compilation failed (Error code: %d)\n", err);
+
+    // Build log
+    size_t log_size;
+    CHECK(clGetProgramBuildInfo(program, device, CL_PROGRAM_BUILD_LOG, 0, NULL,
+                                &log_size));
+    char *log = (char *)malloc(log_size);
+    CHECK(clGetProgramBuildInfo(program, device, CL_PROGRAM_BUILD_LOG, log_size,
+                                log, NULL));
+    printf("      Build log:\n%s\n", log);
+    free(log);
+    goto cleanup;
+  }
+
+  printf("      [OK] Kernel compiled successfully!\n");
+
+cleanup:
+  if (program)
+    clReleaseProgram(program);
+  if (context)
+    clReleaseContext(context);
+  printf("\n");
+
+  return exit_err;
+}
+
+int main() {
+  cl_uint num_platforms;
+  cl_platform_id *platforms = NULL;
+
+  // Get number of platforms
+  CHECK(clGetPlatformIDs(0, NULL, &num_platforms));
+
+  printf("Found %d OpenCL platform(s)\n\n", num_platforms);
+
+  if (num_platforms == 0) {
+    printf("No OpenCL platforms found!\n");
+    return EXIT_FAILURE;
+  }
+
+  // Allocate memory for platforms
+  platforms = (cl_platform_id *)malloc(sizeof(cl_platform_id) * num_platforms);
+
+  // Get platform IDs
+  CHECK(clGetPlatformIDs(num_platforms, platforms, NULL));
+
+  // Query each platform and test kernel compilation
+  for (cl_uint i = 0; i < num_platforms; i++) {
+    char platform_name[BUF_LEN];
+    char platform_vendor[BUF_LEN];
+    char platform_version[BUF_LEN];
+
+    CHECK(clGetPlatformInfo(platforms[i], CL_PLATFORM_NAME,
+                            sizeof(platform_name), platform_name, NULL));
+    CHECK(clGetPlatformInfo(platforms[i], CL_PLATFORM_VENDOR,
+                            sizeof(platform_vendor), platform_vendor, NULL));
+    CHECK(clGetPlatformInfo(platforms[i], CL_PLATFORM_VERSION,
+                            sizeof(platform_version), platform_version, NULL));
+
+    printf("Platform %d: %s\n", i, platform_name);
+    printf("  Vendor: %s\n", platform_vendor);
+    printf("  Version: %s\n", platform_version);
+
+    // Test kernel compilation
+    CHECK(test_kernel_compilation(platforms[i]));
+  }
+
+cleanup:
+  if (platforms)
+    free(platforms);
+
+  if (exit_err == CL_SUCCESS)
+    return EXIT_SUCCESS;
+
+  return EXIT_FAILURE;
+}

test/compilers/opencl.nix

@@ -0,0 +1,104 @@
+{
+  stdenv,
+  ocl-icd,
+  opencl-headers,
+  pocl,
+  clinfo,
+  runCommand,
+  lib,
+}:
+
+stdenv.mkDerivation (finalAttrs: {
+  pname = "opencl-pocl-test";
+  version = "1.0.0";
+
+  src = ./opencl.c;
+
+  dontUnpack = true;
+  dontConfigure = true;
+
+  buildInputs = [
+    ocl-icd
+    opencl-headers
+  ];
+
+  buildPhase = ''
+    runHook preBuild
+
+    $CC -Wall -Wextra -D CL_TARGET_OPENCL_VERSION=100 $src -o ocl-hello -lOpenCL
+
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p $out/bin
+    cp ocl-hello $out/bin
+
+    runHook postInstall
+  '';
+
+  passthru = {
+    test-icd =
+      runCommand "custom-clinfo"
+        {
+          nativeBuildInputs =
+            assert !(lib.hasPrefix "pocl" ocl-icd.pname);
+            [
+              clinfo
+              finalAttrs.finalPackage
+              pocl
+            ];
+
+          env = {
+            POCL_DEBUG = "error,warn";
+            POCL_CACHE_DIR = "/build/pocl_cache";
+          };
+
+          requiredSystemFeatures = [ "sys-devices" ];
+        }
+
+        ''
+          set -x
+
+          mkdir $out
+
+          clinfo -l >$out/clinfo
+          clinfo >$out/clinfo-full
+
+          ocl-hello >$out/hello
+
+          for i in $out/*; do
+            grep "Portable Computing Language" $i
+          done
+
+          echo $OCL_ICD_VENDORS >$out/env
+
+          grep "pocl.*/etc/OpenCL/vendors" $out/env
+
+          set +x
+        '';
+    # this needs: ocl-icd = pocl-noicd
+    test-noicd =
+      runCommand "custom-clinfo"
+        {
+          nativeBuildInputs = [
+            finalAttrs.finalPackage
+          ];
+
+          env = {
+            POCL_DEBUG = "error,warn";
+            POCL_CACHE_DIR = "/build/pocl_cache";
+          };
+
+          requiredSystemFeatures = [ "sys-devices" ];
+        }
+
+        ''
+          ocl-hello >$out
+
+          grep "Portable Computing Language" $out
+        '';
+  };
+})

test/compilers/pocl.nix

@@ -2,25 +2,26 @@
   runCommand,
   pocl,
   clinfo,
-  writableTmpDirAsHomeHook,
 }:
 
 runCommand "clinfo-pocl"
   {
     nativeBuildInputs = [
       clinfo
-      writableTmpDirAsHomeHook
+      pocl
     ];
 
     requiredSystemFeatures = [ "sys-devices" ];
 
     env = {
       POCL_DEBUG = "error,warn";
-      OCL_ICD_VENDORS = "${pocl}/etc/OpenCL/vendors";
+      POCL_CACHE_DIR = "/build/pocl_cache";
     };
   }
   ''
-    set -x
-    clinfo | tee $out
-    set +x
+    echo $OCL_ICD_VENDORS
+    clinfo >$out
+
+    # check that we have PoCL:
+    grep "Portable Computing Language" $out
   ''