[Libomptarget] Only build GPU tests if a GPU is found on the system

[jhuber6]

Summary

Currently we build tests as long as the libraries are found on the
machine. This doesn't necessarily mean there is a GPU to use though.
This patch changes it to where we only will build the tests if we found
a compatible GPU via `nvptx-arch` or `amdgpu-arch`.

The only downside to this I could see if someone were to build LLVM on a
home node of a cluster and then wished to run the tests after switching
to a compute node. For this I think we should allow it to be overridden.
I think that's better than allowing us to run tests that will fail by
default.

[tianshilei1992]

LG

[JonChesterfield]

This doesn't tell CI to set LIBOMPTARGET_FORCE_AMDGPU_TESTS, can we do that now so it doesn't get forgotten?

[jhuber6]

In D142018#4063850, @JonChesterfield wrote:

This doesn't tell CI to set LIBOMPTARGET_FORCE_AMDGPU_TESTS, can we do that now so it doesn't get forgotten?

Yes, good point. Where do we store that information? I've never interfaced with the CI.

openmp/libomptarget/cmake/Modules/LibomptargetGetDependencies.cmake

 if(LIBOMPTARGET_NVPTX_ARCH)
   execute_process(COMMAND ${LIBOMPTARGET_NVPTX_ARCH}
                   OUTPUT_VARIABLE LIBOMPTARGET_NVPTX_ARCH_OUTPUT
                   OUTPUT_STRIP_TRAILING_WHITESPACE)
   string(FIND "${LIBOMPTARGET_NVPTX_ARCH_OUTPUT}" "\n" first_arch_string)
   string(SUBSTRING "${LIBOMPTARGET_NVPTX_ARCH_OUTPUT}" 0 ${first_arch_string}
          arch_string)
   if(arch_string)
+    set(LIBOMPTARGET_FOUND_NVIDIA_GPU TRUE)
     set(LIBOMPTARGET_DEP_CUDA_ARCH "${arch_string}")
   endif()
 endif()
 
 set(LIBOMPTARGET_DEP_CUDA_FOUND ${CUDA_FOUND})
 set(LIBOMPTARGET_DEP_CUDA_INCLUDE_DIRS ${CUDA_INCLUDE_DIRS})
 
 mark_as_advanced(

 find_package_handle_standard_args(
   LIBOMPTARGET_DEP_CUDA_DRIVER
   DEFAULT_MSG
   LIBOMPTARGET_DEP_CUDA_DRIVER_LIBRARIES)
 
 mark_as_advanced(LIBOMPTARGET_DEP_CUDA_DRIVER_LIBRARIES)
 
 ################################################################################
+# Looking for AMD GPUs...
+################################################################################
+
+find_program(LIBOMPTARGET_AMDGPU_ARCH NAMES amdgpu-arch PATHS ${LLVM_BINARY_DIR}/bin)
+if(LIBOMPTARGET_AMDGPU_ARCH)
+  execute_process(COMMAND ${LIBOMPTARGET_AMDGPU_ARCH}
+                  OUTPUT_VARIABLE LIBOMPTARGET_AMDGPU_ARCH_OUTPUT
+                  OUTPUT_STRIP_TRAILING_WHITESPACE)
+  string(FIND "${LIBOMPTARGET_AMDGPU_ARCH_OUTPUT}" "\n" first_arch_string)
+  string(SUBSTRING "${LIBOMPTARGET_AMDGPU_ARCH_OUTPUT}" 0 ${first_arch_string}
+         arch_string)
+  if(arch_string)
+    set(LIBOMPTARGET_FOUND_AMDGPU_GPU TRUE)
+    set(LIBOMPTARGET_DEP_AMDGPU_ARCH "${arch_string}")
+  endif()
+endif()
+
+
+################################################################################
 # Looking for VEO...
 ################################################################################
 
 find_path (
   LIBOMPTARGET_DEP_VEO_INCLUDE_DIR
   NAMES
     ve_offload.h
   PATHS

openmp/libomptarget/plugins/amdgpu/CMakeLists.txt

 set_target_properties(omptarget.rtl.amdgpu PROPERTIES 
   INSTALL_RPATH "$ORIGIN" BUILD_RPATH "$ORIGIN:${CMAKE_CURRENT_BINARY_DIR}/.."
   CXX_VISIBILITY_PRESET protected)
 
 # Report to the parent scope that we are building a plugin for hsa.
 # This controls whether tests are run for the nvptx offloading target
 # Run them if libhsa is available, or if the user explicitly asked for dlopen
 # Otherwise this plugin is being built speculatively and there may be no hsa available
-if (${hsa-runtime64_FOUND} OR LIBOMPTARGET_FORCE_DLOPEN_LIBHSA)
+option(LIBOMPTARGET_FORCE_AMDGPU_TESTS "Build AMDGPU libomptarget tests" OFF)
+if (LIBOMPTARGET_FOUND_AMDGPU_GPU OR LIBOMPTARGET_FORCE_AMDGPU_TESTS)
   # Report to the parent scope that we are building a plugin for amdgpu
   set(LIBOMPTARGET_SYSTEM_TARGETS "${LIBOMPTARGET_SYSTEM_TARGETS} amdgcn-amd-amdhsa amdgcn-amd-amdhsa-oldDriver" PARENT_SCOPE)
   set(LIBOMPTARGET_SYSTEM_TARGETS "${LIBOMPTARGET_SYSTEM_TARGETS} amdgcn-amd-amdhsa amdgcn-amd-amdhsa-LTO" PARENT_SCOPE)
   list(APPEND LIBOMPTARGET_TESTED_PLUGINS "omptarget.rtl.amdgpu")
   set(LIBOMPTARGET_TESTED_PLUGINS "${LIBOMPTARGET_TESTED_PLUGINS}" PARENT_SCOPE)
 else()
   libomptarget_say("Not generating amdgcn test targets as libhsa is not linkable")
   return()
 endif()
 

openmp/libomptarget/plugins/cuda/CMakeLists.txt

 target_include_directories(omptarget.rtl.cuda PRIVATE
   ${LIBOMPTARGET_INCLUDE_DIR}
 )
 
 # Report to the parent scope that we are building a plugin for CUDA.
 # This controls whether tests are run for the nvptx offloading target
 # Run them if libcuda is available, or if the user explicitly asked for dlopen
 # Otherwise this plugin is being built speculatively and there may be no cuda available
-if (LIBOMPTARGET_CAN_LINK_LIBCUDA OR LIBOMPTARGET_FORCE_DLOPEN_LIBCUDA)
+option(LIBOMPTARGET_FORCE_NVIDIA_TESTS "Build NVIDIA libomptarget tests" OFF)
+if (LIBOMPTARGET_FOUND_NVIDIA_GPU OR LIBOMPTARGET_FORCE_NVIDIA_TESTS)
   libomptarget_say("Enable tests using CUDA plugin")
   set(LIBOMPTARGET_SYSTEM_TARGETS "${LIBOMPTARGET_SYSTEM_TARGETS} nvptx64-nvidia-cuda nvptx64-nvidia-cuda-oldDriver" PARENT_SCOPE)
   set(LIBOMPTARGET_SYSTEM_TARGETS "${LIBOMPTARGET_SYSTEM_TARGETS} nvptx64-nvidia-cuda nvptx64-nvidia-cuda-LTO" PARENT_SCOPE)
   list(APPEND LIBOMPTARGET_TESTED_PLUGINS "omptarget.rtl.cuda")
   set(LIBOMPTARGET_TESTED_PLUGINS "${LIBOMPTARGET_TESTED_PLUGINS}" PARENT_SCOPE)
 else()
   libomptarget_say("Disabling tests using CUDA plugin as cuda may not be available")
 endif()