Auto-detect compilation settings based on present compilers/libraries

CMakeLists.txt

@@ -4,15 +4,19 @@ project(Ginkgo LANGUAGES C CXX VERSION 1.1.1 DESCRIPTION "A numerical linear alg
 set(Ginkgo_VERSION_TAG "develop")
 set(PROJECT_VERSION_TAG ${Ginkgo_VERSION_TAG})
 
+# Determine which executors can be compiled
+include(cmake/hip_path.cmake)
+include(cmake/autodetect_executors.cmake)
+
 # Ginkgo configuration options
 option(GINKGO_DEVEL_TOOLS "Add development tools to the build system" ON)
 option(GINKGO_BUILD_TESTS "Generate build files for unit tests" ON)
 option(GINKGO_BUILD_EXAMPLES "Build Ginkgo's examples" ON)
 option(GINKGO_BUILD_BENCHMARKS "Build Ginkgo's benchmarks" ON)
 option(GINKGO_BUILD_REFERENCE "Compile reference CPU kernels" ON)
-option(GINKGO_BUILD_OMP "Compile OpenMP kernels for CPU" OFF)
-option(GINKGO_BUILD_CUDA "Compile kernels for NVIDIA GPUs" OFF)
-option(GINKGO_BUILD_HIP "Compile kernels for AMD or NVIDIA GPUs" OFF)
+option(GINKGO_BUILD_OMP "Compile OpenMP kernels for CPU" ${GINKGO_HAS_OMP})
+option(GINKGO_BUILD_CUDA "Compile kernels for NVIDIA GPUs" ${GINKGO_HAS_CUDA})
+option(GINKGO_BUILD_HIP "Compile kernels for AMD or NVIDIA GPUs" ${GINKGO_HAS_HIP})
 option(GINKGO_BUILD_DOC "Generate documentation" OFF)
 option(GINKGO_SKIP_DEPENDENCY_UPDATE
     "Do not update dependencies each time the project is rebuilt" ON)
@@ -120,16 +124,7 @@ set(GINKGO_HIP_PLATFORM_NVCC 0)
 set(GINKGO_HIP_PLATFORM_HCC 0)
 
 if (GINKGO_BUILD_HIP)
-    if(NOT DEFINED HIP_PATH)
-        if(NOT DEFINED ENV{HIP_PATH})
-            set(HIP_PATH "/opt/rocm/hip" CACHE PATH "Path to which HIP has been installed")
-            set(ENV{HIP_PATH} ${HIP_PATH})
-        else()
-            set(HIP_PATH $ENV{HIP_PATH} CACHE PATH "Path to which HIP has been installed")
-        endif()
-    endif()
-
-    find_program(GINKGO_HIPCONFIG_PATH hipconfig HINTS "${HIP_PATH}/bin")
+    # GINKGO_HIPCONFIG_PATH and HIP_PATH are set in cmake/hip_path.cmake
     if(GINKGO_HIPCONFIG_PATH)
         execute_process(COMMAND ${GINKGO_HIPCONFIG_PATH} --platform OUTPUT_VARIABLE GINKGO_HIP_PLATFORM)
     elseif(DEFINED ENV{HIP_PLATFORM})

INSTALL.md

@@ -28,11 +28,13 @@ Ginkgo adds the following additional switches to control what is being built:
 *   `-DGINKGO_BUILD_REFERENCE={ON, OFF}` build reference implementations of the
     kernels, useful for testing, default is `ON`
 *   `-DGINKGO_BUILD_OMP={ON, OFF}` builds optimized OpenMP versions of the kernels,
-    default is `OFF`
+    default is `ON` if the selected C++ compiler supports OpenMP, `OFF` otherwise.
 *   `-DGINKGO_BUILD_CUDA={ON, OFF}` builds optimized cuda versions of the kernels
-    (requires CUDA), default is `OFF`
+    (requires CUDA), default is `ON` if a CUDA compiler could be detected,
+    `OFF` otherwise.
 *   `-DGINKGO_BUILD_HIP={ON, OFF}` builds optimized HIP versions of the kernels
-    (requires HIP), default is `OFF`
+    (requires HIP), default is `ON` if an installation of HIP could be detected,
+    `OFF` otherwise.
 *   `-DGINKGO_HIP_AMDGPU="gpuarch1;gpuarch2"` the amdgpu_target(s) variable
     passed to hipcc for the `hcc` HIP backend. The default is none (auto).
 *   `-DGINKGO_BUILD_DOC={ON, OFF}` creates an HTML version of Ginkgo's documentation
@@ -104,7 +106,7 @@ For example, to build everything (in debug mode), use:
 ```cmake
 cmake  -G "Unix Makefiles" -H. -BDebug -DCMAKE_BUILD_TYPE=Debug -DGINKGO_DEVEL_TOOLS=ON \
     -DGINKGO_BUILD_TESTS=ON -DGINKGO_BUILD_REFERENCE=ON -DGINKGO_BUILD_OMP=ON \
-    -DGINKGO_BUILD_CUDA=ON -DGINKGO_BUILD_HIP=ON \
+    -DGINKGO_BUILD_CUDA=ON -DGINKGO_BUILD_HIP=ON
 cmake --build Debug
 ```
 
@@ -114,8 +116,10 @@ generators. Other CMake generators are untested.
 ### Building Ginkgo with HIP support
 Ginkgo provides a [HIP](https://github.com/ROCm-Developer-Tools/HIP) backend.
 This allows to compile optimized versions of the kernels for either AMD or
-NVIDIA GPUs. To build Ginkgo with this backend, use the CMake option
-`-DGINKGO_BUILD_HIP=ON`.
+NVIDIA GPUs. The CMake configuration step will try to auto-detect the presence
+of HIP either at `/opt/rocm/hip` or at the path specified by `HIP_PATH` as a
+CMake parameter (`-DHIP_PATH=`) or environment variable (`export HIP_PATH=`),
+unless `-DGINKGO_BUILD_HIP=ON/OFF` is set explicitly.
 
 #### Correctly installing HIP toolkits and dependencies for Ginkgo
 In general, Ginkgo's HIP backend requires the following packages:

cmake/autodetect_executors.cmake

@@ -0,0 +1,27 @@
+set(GINKGO_HAS_OMP OFF)
+set(GINKGO_HAS_CUDA OFF)
+set(GINKGO_HAS_HIP OFF)
+find_package(OpenMP)
+include(CheckLanguage)
+check_language(CUDA)
+
+if(OpenMP_CXX_FOUND)
+    if(NOT DEFINED GINKGO_BUILD_OMP)
+        message(STATUS "Enabling OpenMP executor")
+    endif()
+    set(GINKGO_HAS_OMP ON)
+endif()
+
+if(CMAKE_CUDA_COMPILER)
+    if(NOT DEFINED GINKGO_BUILD_CUDA)
+        message(STATUS "Enabling CUDA executor")
+    endif()
+    set(GINKGO_HAS_CUDA ON)
+endif()
+
+if(GINKGO_HIPCONFIG_PATH)
+    if(NOT DEFINED GINKGO_BUILD_HIP)
+        message(STATUS "Enabling HIP executor")
+    endif()
+    set(GINKGO_HAS_HIP ON)
+endif()

cmake/hip_path.cmake

@@ -0,0 +1,13 @@
+if(NOT DEFINED HIP_PATH)
+    if(NOT DEFINED ENV{HIP_PATH})
+        set(HIP_PATH "/opt/rocm/hip" CACHE PATH "Path to which HIP has been installed")
+        set(ENV{HIP_PATH} ${HIP_PATH})
+    else()
+        set(HIP_PATH $ENV{HIP_PATH} CACHE PATH "Path to which HIP has been installed")
+    endif()
+endif()
+
+find_program(GINKGO_HIPCONFIG_PATH hipconfig HINTS "${HIP_PATH}/bin")
+if(GINKGO_HIPCONFIG_PATH)
+    message(STATUS "Found hipconfig: ${GINKGO_HIPCONFIG_PATH}")
+endif()