Add DPCTL_TARGET_CUDA Boolean cmake option

Also DPCTL_SYCL_TARGETS parameter can be used to specify targets
to build for.

DPCTL_TARGET_CUDA could be set via cmake option, or via environment
variable, e.g.

```
$ DPCTL_TARGET_CUDA=1 python scripts/build_locally.py --verbose
```

Author: oleksandr-pavlyk

CMakeLists.txt

@@ -17,9 +17,30 @@ option(DPCTL_GENERATE_COVERAGE
     "Build dpctl with coverage instrumentation"
     OFF
 )
+option(DPCTL_TARGET_CUDA
+    "Build DPCTL to target CUDA devices"
+    OFF
+)
 
 find_package(IntelSYCL REQUIRED PATHS ${CMAKE_SOURCE_DIR}/cmake NO_DEFAULT_PATH)
 
+set(_dpctl_sycl_targets)
+if ("x${DPCTL_SYCL_TARGETS}" STREQUAL "x")
+   if(DPCTL_TARGET_CUDA)
+      set(_dpctl_sycl_targets "nvptx64-nvidia-cuda,spir64-unknown-unknown")
+   else()
+      if(DEFINED ENV{DPCTL_TARGET_CUDA})
+          set(_dpctl_sycl_targets "nvptx64-nvidia-cuda,spir64-unknown-unknown")
+      endif()
+   endif()
+else()
+   set(_dpctl_sycl_targets ${DPCTL_SYCL_TARGETS})
+endif()
+
+if(_dpctl_sycl_targets)
+   message(STATUS "Compiling for -fsycl-targets=${_dpctl_sycl_targets}")
+endif()
+
 add_subdirectory(libsyclinterface)
 
 file(GLOB _dpctl_capi_headers dpctl/apis/include/*.h*)

dpctl/CMakeLists.txt

@@ -144,17 +144,19 @@ function(build_dpctl_ext _trgt _src _dest)
     Python_add_library(${_trgt} MODULE WITH_SOABI ${_generated_src})
     if (BUILD_DPCTL_EXT_SYCL)
         add_sycl_to_target(TARGET ${_trgt} SOURCES ${_generated_src})
-        # make fat binary
-        target_compile_options(
-            ${_trgt}
-            PRIVATE
-            -fsycl-targets=nvptx64-nvidia-cuda,spir64-unknown-unknown
-        )
-	target_link_options(
-	    ${_trgt}
-	    PRIVATE
-	    -fsycl-targets=nvptx64-nvidia-cuda,spir64-unknown-unknown
-	)
+	if(_dpctl_sycl_targets)
+	    # make fat binary
+            target_compile_options(
+                ${_trgt}
+                PRIVATE
+                -fsycl-targets=${_dpctl_sycl_targets}
+            )
+	    target_link_options(
+	        ${_trgt}
+	        PRIVATE
+	        -fsycl-targets=${_dpctl_sycl_targets}
+	    )
+	endif()
     endif()
     target_include_directories(${_trgt} PRIVATE ${NumPy_INCLUDE_DIR} ${DPCTL_INCLUDE_DIR})
     add_dependencies(${_trgt} _build_time_create_dpctl_include_copy ${_cythonize_trgt})

dpctl/tensor/CMakeLists.txt

@@ -141,17 +141,19 @@ list(APPEND _tensor_impl_sources
 set(python_module_name _tensor_impl)
 pybind11_add_module(${python_module_name} MODULE ${_tensor_impl_sources})
 add_sycl_to_target(TARGET ${python_module_name} SOURCES ${_tensor_impl_sources})
-# make fat binary
-target_compile_options(
-    ${python_module_name}
-    PRIVATE
-    -fsycl-targets=nvptx64-nvidia-cuda,spir64-unknown-unknown
-)
-target_link_options(
-    ${python_module_name}
-    PRIVATE
-    -fsycl-targets=nvptx64-nvidia-cuda,spir64-unknown-unknown
-)
+if(_dpctl_sycl_targets)
+    # make fat binary
+    target_compile_options(
+        ${python_module_name}
+        PRIVATE
+        -fsycl-targets=${_dpctl_sycl_targets}
+    )
+    target_link_options(
+        ${python_module_name}
+        PRIVATE
+        -fsycl-targets=${_dpctl_sycl_targets}
+    )
+endif()
 
 set(_clang_prefix "")
 if (WIN32)

dpctl/utils/CMakeLists.txt

@@ -21,17 +21,19 @@ pybind11_add_module(${python_module_name} MODULE
   ${_module_src}
 )
 add_sycl_to_target(TARGET ${python_module_name} SOURCES ${_module_src})
-# make fat binary
-target_compile_options(
-    ${python_module_name}
-    PRIVATE
-    -fsycl-targets=nvptx64-nvidia-cuda,spir64-unknown-unknown
-)
-target_link_options(
-    ${python_module_name}
-    PRIVATE
-    -fsycl-targets=nvptx64-nvidia-cuda,spir64-unknown-unknown
-)
+if(_dpctl_sycl_targets)
+    # make fat binary
+    target_compile_options(
+        ${python_module_name}
+        PRIVATE
+        -fsycl-targets=${_dpctl_sycl_targets}
+    )
+    target_link_options(
+        ${python_module_name}
+        PRIVATE
+        -fsycl-targets=${_dpctl_sycl_targets}
+    )
+endif()
 target_include_directories(${python_module_name}
     PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}/../include

libsyclinterface/CMakeLists.txt

@@ -206,16 +206,18 @@ add_library(DPCTLSyclInterface
 )
 add_sycl_to_target(TARGET DPCTLSyclInterface SOURCES ${sources} ${helper_sources})
 # make fat binary
-target_compile_options(
-    DPCTLSyclInterface
-    PRIVATE
-    -fsycl-targets=nvptx64-nvidia-cuda,spir64-unknown-unknown
-)
-target_link_options(
-    DPCTLSyclInterface
-    PRIVATE
-    -fsycl-targets=nvptx64-nvidia-cuda,spir64-unknown-unknown
-)
+if(_dpctl_sycl_targets)
+    target_compile_options(
+        DPCTLSyclInterface
+        PRIVATE
+        -fsycl-targets=${_dpctl_sycl_targets}
+    )
+    target_link_options(
+        DPCTLSyclInterface
+        PRIVATE
+        -fsycl-targets=${_dpctl_sycl_targets}
+   )
+endif()
 
 if(DPCTL_GENERATE_COVERAGE)
     target_link_options(DPCTLSyclInterface

libsyclinterface/tests/CMakeLists.txt

@@ -52,6 +52,7 @@ add_sycl_to_target(
   ${CMAKE_CURRENT_SOURCE_DIR}/test_sycl_queue_interface.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/test_sycl_usm_interface.cpp
 )
+if (_dpctl_sycl_targets)
 # make fat binary
 target_compile_options(
     dpctl_c_api_tests
@@ -63,6 +64,7 @@ target_link_options(
     PRIVATE
     -fsycl-targets=nvptx64-nvidia-cuda,spir64-unknown-unknown
 )
+endif()
 
 if(DPCTL_GENERATE_COVERAGE)
     target_include_directories(dpctl_c_api_tests