add a sample that unloads the OpenCL ICD loader and then reloads it

This sample currently requires a special branch of the OpenCL runtime
loader that includes the unload function.

CMakeLists.txt

@@ -25,10 +25,17 @@ include_directories(${CMAKE_CURRENT_SOURCE_DIR}/include)
 include_directories(${OpenCL_INCLUDE_DIR})
 
 add_subdirectory(external/OpenCL-Headers)
+
+option(SAMPLES_USE_RUNTIME_LOADER "Build with the OpenCL Runtime Loader" ON)
+if (SAMPLES_USE_RUNTIME_LOADER)
+add_subdirectory(external/opencl-runtime-loader)
+set(OpenCL_LIBRARIES OpenCLRuntimeLoader ${CMAKE_DL_LIBS})
+else()
 add_subdirectory(external/opencl-icd-loader)
 set_target_properties(OpenCL PROPERTIES FOLDER "OpenCL-ICD-Loader")
 set_target_properties(cllayerinfo PROPERTIES FOLDER "OpenCL-ICD-Loader")
 set(OpenCL_LIBRARIES OpenCL)
+endif()
 
 if(IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/external/opencl-extension-loader)
     add_subdirectory(external/opencl-extension-loader)

README.md

@@ -39,6 +39,10 @@ Many samples that use extensions additionally require the OpenCL Extension Loade
 
     git clone https://github.com/bashbaug/opencl-extension-loader external/opencl-extension-loader
 
+The loading and unloading sample requires the OpenCL Runtime Loader:
+
+    git clone https://github.com/bashbaug/opencl-runtime-loader external/opencl-runtime-loader
+
 After satisfying the external dependencies create build files using CMake.  For example:
 
     mkdir build && cd build

samples/99_loaderunload/CMakeLists.txt

@@ -0,0 +1,10 @@
+# Copyright (c) 2025 Ben Ashbaugh
+#
+# SPDX-License-Identifier: MIT
+
+add_opencl_sample(
+    TEST
+    NUMBER 99
+    TARGET loaderunload
+    VERSION 120
+    SOURCES main.cpp)

samples/99_loaderunload/main.cpp

@@ -0,0 +1,116 @@
+/*
+// Copyright (c) 2019-2025 Ben Ashbaugh
+//
+// SPDX-License-Identifier: MIT
+*/
+
+#include <stdio.h>
+#include <vector>
+#include <popl/popl.hpp>
+
+#include <CL/opencl.hpp>
+
+static cl_int PrintPlatformInfoSummary(
+    cl::Platform platform )
+{
+    printf("\tName:           %s\n", platform.getInfo<CL_PLATFORM_NAME>().c_str() );
+    printf("\tVendor:         %s\n", platform.getInfo<CL_PLATFORM_VENDOR>().c_str() );
+    printf("\tDriver Version: %s\n", platform.getInfo<CL_PLATFORM_VERSION>().c_str() );
+
+    return CL_SUCCESS;
+}
+
+static void PrintDeviceType(
+    const char* label,
+    cl_device_type type )
+{
+    printf("%s%s%s%s%s%s\n",
+        label,
+        ( type & CL_DEVICE_TYPE_DEFAULT     ) ? "DEFAULT "      : "",
+        ( type & CL_DEVICE_TYPE_CPU         ) ? "CPU "          : "",
+        ( type & CL_DEVICE_TYPE_GPU         ) ? "GPU "          : "",
+        ( type & CL_DEVICE_TYPE_ACCELERATOR ) ? "ACCELERATOR "  : "",
+        ( type & CL_DEVICE_TYPE_CUSTOM      ) ? "CUSTOM "       : "");
+}
+
+static cl_int PrintDeviceInfoSummary(
+    const std::vector<cl::Device>& devices )
+{
+    for( size_t i = 0; i < devices.size(); i++ )
+    {
+        printf("Device[%zu]:\n", i );
+
+        cl_device_type  deviceType = devices[i].getInfo<CL_DEVICE_TYPE>();
+        PrintDeviceType("\tType:           ", deviceType);
+
+        printf("\tName:           %s\n", devices[i].getInfo<CL_DEVICE_NAME>().c_str() );
+        printf("\tVendor:         %s\n", devices[i].getInfo<CL_DEVICE_VENDOR>().c_str() );
+        printf("\tDevice Version: %s\n", devices[i].getInfo<CL_DEVICE_VERSION>().c_str() );
+        printf("\tDriver Version: %s\n", devices[i].getInfo<CL_DRIVER_VERSION>().c_str() );
+    }
+
+    return CL_SUCCESS;
+}
+
+static void PrintPlatformInfo()
+{
+    std::vector<cl::Platform> platforms;
+    cl::Platform::get(&platforms);
+
+    for( size_t i = 0; i < platforms.size(); i++ )
+    {
+        printf( "Platform[%zu]:\n", i );
+        PrintPlatformInfoSummary( platforms[i] );
+
+        std::vector<cl::Device> devices;
+        platforms[i].getDevices(CL_DEVICE_TYPE_ALL, &devices);
+
+        PrintDeviceInfoSummary( devices );
+        printf( "\n" );
+    }
+}
+
+typedef cl_int (CL_API_CALL *_sclpfn_clTeardownOCLRT)(void);
+
+int main(
+    int argc,
+    char** argv )
+{
+    {
+        popl::OptionParser op("Supported Options");
+
+        bool printUsage = false;
+        try {
+            op.parse(argc, argv);
+        } catch (std::exception& e) {
+            fprintf(stderr, "Error: %s\n\n", e.what());
+            printUsage = true;
+        }
+
+        if (printUsage || !op.unknown_options().empty() || !op.non_option_args().empty()) {
+            fprintf(stderr,
+                "Usage: loaderunload [options]\n"
+                "%s", op.help().c_str());
+            return -1;
+        }
+    }
+
+    printf("Initially:\n");
+    PrintPlatformInfo();
+
+    auto clTeardownOCLRT = (_sclpfn_clTeardownOCLRT)
+        clGetExtensionFunctionAddress("clTeardownOCLRT");
+    if (clTeardownOCLRT == nullptr) {
+        printf("Couldn't get a pointer to clTeardownOCLRT()...\n");
+    } else {
+        printf("Initiating teardown...\n");
+        clTeardownOCLRT();
+
+        printf("Now:\n");
+        PrintPlatformInfo();
+    }
+
+    printf("Done.\n");
+
+    return 0;
+}

samples/CMakeLists.txt

@@ -91,3 +91,5 @@ if(BUILD_EXTENSION_SAMPLES)
     add_subdirectory( 14_ooqcommandbuffers )
     add_subdirectory( 15_mutablecommandbufferasserts )
 endif()
+
+add_subdirectory( 99_loaderunload )