cmake: add CMake language support for CUDA/HIP (kokkos#2173)

* cmake: add CMake language support for CUDA/HIP

* Apply suggestions of @brian-kelley

CMakeLists.txt

@@ -127,6 +127,15 @@ ELSE()
   IF (NOT KOKKOSKERNELS_HAS_TRILINOS AND NOT KOKKOSKERNELS_HAS_PARENT)
     # This is a standalone build
     FIND_PACKAGE(Kokkos REQUIRED)
+    IF(Kokkos_COMPILE_LANGUAGE)
+      ENABLE_LANGUAGE(${Kokkos_COMPILE_LANGUAGE})
+      IF(Kokkos_COMPILE_LANGUAGE STREQUAL CUDA)
+        SET(CMAKE_CUDA_ARCHITECTURES ${Kokkos_CUDA_ARCHITECTURES})
+      ENDIF()
+      IF(Kokkos_COMPILE_LANGUAGE STREQUAL HIP)
+        SET(CMAKE_HIP_ARCHITECTURES ${Kokkos_HIP_ARCHITECTURES})
+      ENDIF()
+    ENDIF()
     IF(${Kokkos_VERSION} VERSION_GREATER_EQUAL "4.2.00")
       MESSAGE(STATUS "Found Kokkos version ${Kokkos_VERSION} at ${Kokkos_DIR}")
       IF((${Kokkos_VERSION} VERSION_GREATER "4.3.99"))

cmake/kokkoskernels_tribits.cmake

@@ -85,6 +85,11 @@ ENDIF()
 IF(PARSE_SOURCES)
   LIST(REMOVE_DUPLICATES PARSE_SOURCES)
 ENDIF()
+IF(Kokkos_COMPILE_LANGUAGE)
+  FOREACH(source ${PARSE_SOURCES})
+    SET_SOURCE_FILES_PROPERTIES(${source} PROPERTIES LANGUAGE ${Kokkos_COMPILE_LANGUAGE})
+  ENDFOREACH()
+ENDIF()
 
 ADD_LIBRARY(
   ${LIBRARY_NAME}
@@ -151,6 +156,12 @@ IF (IS_ENABLED)
       SOURCES ${PARSE_SOURCES}
       TESTONLYLIBS ${PARSE_TESTONLYLIBS})
   ELSE()
+    # Set the correct CMake language on all source files for this exe
+    IF(Kokkos_COMPILE_LANGUAGE)
+      FOREACH(source ${PARSE_SOURCES})
+        SET_SOURCE_FILES_PROPERTIES(${source} PROPERTIES LANGUAGE ${Kokkos_COMPILE_LANGUAGE})
+      ENDFOREACH()
+    ENDIF()
     ADD_EXECUTABLE(${EXE_NAME} ${PARSE_SOURCES})
     #AJP, BMK altered:
     IF(KOKKOSKERNELS_ENABLE_TESTS_AND_PERFSUITE)