CMAKE: add CMAKE_CUDA_ARCHITECTURE support

.gitlab/ci/config/initial_config.cmake

@@ -98,8 +98,10 @@ foreach(option IN LISTS options)
   elseif(volta STREQUAL option)
     set(VTKm_CUDA_Architecture "volta" CACHE STRING "")
 
+  # From turing we set the architecture using the cannonical
+  # CMAKE_CUDA_ARCHITECTURES
   elseif(turing STREQUAL option)
-    set(VTKm_CUDA_Architecture "turing" CACHE STRING "")
+    set(CMAKE_CUDA_ARCHITECTURES "75" CACHE STRING "")
 
   elseif(hip STREQUAL option)
     if(CMAKE_VERSION VERSION_LESS_EQUAL 3.20)
@@ -165,7 +167,7 @@ if(SCCACHE_COMMAND)
 
   # Use VTKm_CUDA_Architecture to determine if we need CUDA sccache setup
   # since this will also capture when kokkos is being used with CUDA backing
-  if(DEFINED VTKm_CUDA_Architecture)
+  if(DEFINED VTKm_CUDA_Architecture OR DEFINED CMAKE_CUDA_ARCHITECTURES)
     set(CMAKE_CUDA_COMPILER_LAUNCHER "${SCCACHE_COMMAND}" CACHE STRING "")
   endif()
 endif()

CMake/VTKmConfig.cmake.in

@@ -115,8 +115,15 @@ endif()
 # replace this with setting `cuda_architecture_flags` as part of the
 # EXPORT_PROPERTIES of the vtkm_cuda target
 if(VTKm_ENABLE_CUDA AND VTKM_FROM_INSTALL_DIR)
-  set_target_properties(vtkm::cuda PROPERTIES cuda_architecture_flags "@VTKm_CUDA_Architecture_Flags@")
-  set_target_properties(vtkm::cuda PROPERTIES requires_static_builds TRUE)
+
+  set_target_properties(vtkm::cuda PROPERTIES
+
+    # Canonical way of setting CUDA arch
+    CUDA_ARCHITECTURES      "@CMAKE_CUDA_ARCHITECTURES@"
+
+    # Legacy way of setting CUDA arch
+    cuda_architecture_flags "@VTKm_CUDA_Architecture_Flags@"
+    requires_static_builds TRUE)
 
   # If VTK-m is built with 3.18+ and the consumer is < 3.18 we need to drop
   # these properties as they break the VTK-m cuda flag logic

CMake/VTKmDeviceAdapters.cmake

@@ -108,10 +108,25 @@ if(VTKm_ENABLE_CUDA)
       target_compile_features(vtkm_cuda INTERFACE cxx_std_14)
     endif()
 
+    # If we have specified CMAKE_CUDA_ARCHITECTURES and CMake >= 3.18 we are
+    # done setting up vtkm_cuda.
+    if(NOT DEFINED CMAKE_CUDA_ARCHITECTURES OR CMAKE_VERSION VERSION_LESS 3.18)
+
+      # Recommend user to use CMAKE_CUDA_ARCHITECTURES instead
+      if(DEFINED VTKm_CUDA_Architecture AND CMAKE_VERSION VERSION_GREATER_EQUAL 3.18)
+        message(DEPRECATION "VTKm_CUDA_Architecture used, use CMAKE_CUDA_ARCHITECTURES instead in CMake >= 3.18")
+      endif()
+
+      # We disable CMAKE_CUDA_ARCHITECTURES since we add the arch manually
+      set(CMAKE_CUDA_ARCHITECTURES OFF)
+
       # add the -gencode flags so that all cuda code
       # way compiled properly
 
       #---------------------------------------------------------------------------
+      # When using CMAKE >= 3.18 use instead CMAKE_CUDA_ARCHITECTURES since it
+      # is the canonical way to specify archs in modern CMAKE.
+      #
       # Populates CMAKE_CUDA_FLAGS with the best set of flags to compile for a
       # given GPU architecture. The majority of developers should leave the
       # option at the default of 'native' which uses system introspection to
@@ -207,7 +222,8 @@ if(VTKm_ENABLE_CUDA)
       elseif(VTKm_CUDA_Architecture STREQUAL "maxwell")
         set(arch_flags --generate-code=arch=compute_50,code=sm_50)
       elseif(VTKm_CUDA_Architecture STREQUAL "pascal")
-      set(arch_flags --generate-code=arch=compute_60,code=sm_60)
+        set(arch_flags --generate-code=arch=compute_60,code=sm_60
+                       --generate-code=arch=compute_61,code=sm_61)
       elseif(VTKm_CUDA_Architecture STREQUAL "volta")
         set(arch_flags --generate-code=arch=compute_70,code=sm_70)
       elseif(VTKm_CUDA_Architecture STREQUAL "turing")
@@ -233,7 +249,6 @@ if(VTKm_ENABLE_CUDA)
       endif()
 
       if(policy_105_enabled STREQUAL "NEW")
-      set(CMAKE_CUDA_ARCHITECTURES OFF)
         target_compile_options(vtkm_cuda INTERFACE $<$<COMPILE_LANGUAGE:CUDA>:${arch_flags}>)
         target_link_options(vtkm_cuda INTERFACE $<DEVICE_LINK:${arch_flags}>)
       else()
@@ -250,6 +265,7 @@ if(VTKm_ENABLE_CUDA)
       unset(arch_flags)
     endif()
   endif()
+endif()
 
 #-----------------------------------------------------------------------------
 # Kokkos with its Cuda backend enabled, expects everything to be compiled using its

CMake/VTKmWrappers.cmake

@@ -373,8 +373,6 @@ function(vtkm_add_target_information uses_vtkm_target)
     set_target_properties(${targets} PROPERTIES POSITION_INDEPENDENT_CODE ON)
     set_target_properties(${targets} PROPERTIES CUDA_SEPARABLE_COMPILATION ON)
   endif()
-  # CUDA_ARCHITECTURES added in CMake 3.18
-  set_target_properties(${targets} PROPERTIES CUDA_ARCHITECTURES OFF)
 
   if(VTKm_TI_DROP_UNUSED_SYMBOLS)
     foreach(target IN LISTS targets)

docs/changelog/enable-cmake-cuda-architectures.md

@@ -0,0 +1,10 @@
+## Enable CMAKE_CUDA_ARCHITECTURES
+
+When using _CMake_ > 3.18, `CMAKE_CUDA_ARCHITECTURES` can now be used instead of
+`VTKm_CUDA_Architecture` to specify the list of architectures desired for the
+compilation of _CUDA_ sources. 
+
+Since `CMAKE_CUDA_ARCHITECTURES` is the canonical method of specifying _CUDA_
+architectures in _CMake_ and it is more flexible, for instance we can also
+specify _CUDA_ virtual architectures, from _CMake_ 3.18 explicitly setting
+`VTKm_CUDA_Architecture` will be deprecated whilst still supported.