Make sure vtk-m libraries under CUDA 8 are always built statically

CMake/VTKmDeviceAdapters.cmake

@@ -134,6 +134,17 @@ if(VTKm_ENABLE_CUDA AND NOT TARGET vtkm::cuda)
     add_library(vtkm::cuda UNKNOWN IMPORTED GLOBAL)
   endif()
 
+  # Workaround issue with CUDA 8.X where virtual don't work when building
+  # VTK-m as shared. We don't want to force BUILD_SHARED_LIBS to a specific
+  # value as that could impact other projects that embed VTK-m. Instead what
+  # we do is make sure that libraries built by vtkm_library() are static
+  # if they use cuda
+  if(CMAKE_CUDA_COMPILER_VERSION VERSION_LESS 9.0)
+    set_target_properties(vtkm::cuda PROPERTIES REQUIRES_STATIC_BUILDS TRUE)
+  else()
+    set_target_properties(vtkm::cuda PROPERTIES REQUIRES_STATIC_BUILDS FALSE)
+  endif()
+
   set_target_properties(vtkm::cuda PROPERTIES
     INTERFACE_COMPILE_OPTIONS $<$<COMPILE_LANGUAGE:CUDA>:--expt-relaxed-constexpr>
   )

CMake/VTKmWrappers.cmake

@@ -282,16 +282,31 @@ function(vtkm_library)
   endif()
   set(lib_name ${VTKm_LIB_NAME})
 
+  if(VTKm_LIB_STATIC)
+    set(VTKm_LIB_type STATIC)
+  else()
+    if(VTKm_LIB_SHARED)
+      set(VTKm_LIB_type SHARED)
+    endif()
+    #if cuda requires static libaries force
+    #them no matter what
+    if(TARGET vtkm::cuda)
+      get_target_property(force_static vtkm::cuda REQUIRES_STATIC_BUILDS)
+      if(force_static)
+        set(VTKm_LIB_type STATIC)
+        message("Forcing ${lib_name} to be built statically as we are using CUDA 8.X, which doesn't support virtuals sufficiently in dynamic libraries.")
+      endif()
+    endif()
+
+  endif()
+
+
   if(TARGET vtkm::cuda)
     vtkm_compile_as_cuda(cu_srcs ${VTKm_LIB_WRAP_FOR_CUDA})
     set(VTKm_LIB_WRAP_FOR_CUDA ${cu_srcs})
   endif()
 
-  if(VTKm_LIB_STATIC)
-    set(VTKm_LIB_type STATIC)
-  elseif(VTKm_LIB_SHARED)
-    set(VTKm_LIB_type SHARED)
-  endif()
+
 
   add_library(${lib_name}
               ${VTKm_LIB_type}