Making vtkm-cont depend on diy.

CMakeLists.txt

@@ -221,6 +221,11 @@ find_package(Pyexpander)
 
 #-----------------------------------------------------------------------------
 # Add subdirectories
+if(VTKm_ENABLE_MPI)
+  # This `if` is temporary and will be removed once `diy` supports building
+  # without MPI.
+  add_subdirectory(diy)
+endif()
 add_subdirectory(vtkm)
 
 #-----------------------------------------------------------------------------

vtkm/cont/CMakeLists.txt

@@ -150,5 +150,10 @@ if(VTKm_ENABLE_CUDA)
   add_dependencies(vtkm_cont vtkm_cont_cuda)
 endif()
 
+if(VTKm_ENABLE_MPI)
+  # This will become a required dependency eventually.
+  target_link_libraries(vtkm_cont PRIVATE diy)
+endif()
+
 #-----------------------------------------------------------------------------
 add_subdirectory(testing)

vtkm/internal/CMakeLists.txt

@@ -28,6 +28,7 @@ set(VTKM_USE_64BIT_IDS ${VTKm_USE_64BIT_IDS})
 
 set(VTKM_ENABLE_CUDA ${VTKm_ENABLE_CUDA})
 set(VTKM_ENABLE_TBB ${VTKm_ENABLE_TBB})
+set(VTKM_ENABLE_MPI ${VTKm_ENABLE_MPI})
 
 vtkm_get_kit_name(kit_name kit_dir)
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/Configure.h.in

vtkm/internal/Configure.h.in

@@ -263,6 +263,9 @@
 #cmakedefine VTKM_ENABLE_TBB
 #endif
 
+//Mark if we are building with MPI enabled.
+#cmakedefine VTKM_ENABLE_MPI
+
 #if __cplusplus >= 201103L || \
     ( defined(VTKM_MSVC) && _MSC_VER >= 1800  ) || \
     ( defined(VTKM_ICC)  && defined(__INTEL_CXX11_MODE__) )