cmake: rework how MPI compiler wrappers are handled

we now require the user to specify the MPI compiler wrappers to be
defined as the main compilers via CMAKE_<LANG>_COMPILER or alike

Author: torbjoernk

CMakeLists.txt

@@ -25,7 +25,12 @@ option(pfasst_DEFAULT_RAND_SEED "Using a hardcoded random seed"
 
 if(${pfasst_WITH_MPI})
     find_package(MPI REQUIRED)
-    message(STATUS "Using MPI C++ Compiler: ${MPI_CXX_COMPILER}")
+    if(NOT "${CMAKE_CXX_COMPILER}" STREQUAL "${MPI_CXX_COMPILER}")
+        message(STATUS "C++ Compiler: ${CMAKE_CXX_COMPILER}")
+        message(STATUS "MPI C++ Compiler Wrapper: ${MPI_CXX_COMPILER}")
+        message(FATAL_ERROR "Please make sure to set CXX and CC to the MPI compiler wrappers!")
+    endif()
+    message(STATUS "Using MPI C++ Compiler Wrapper: ${MPI_CXX_COMPILER}")
     add_definitions(-DWITH_MPI)
 endif()
 

examples/advection_diffusion/CMakeLists.txt

@@ -41,17 +41,4 @@ foreach(example ${all_advec_examples})
     endif()
 endforeach(example)
 
-if(${pfasst_WITH_MPI})
-    include_directories(${MPI_CXX_INCLUDE_PATH})
-    foreach(example ${advec_mpi_examples})
-        if(MPI_COMPILE_FLAGS)
-            set_target_properties(${example} PROPERTIES COMPILE_FLAGS "${MPI_COMPILE_FLAGS}")
-        endif()
-        if(MPI_LINK_FLAGS)
-            set_target_properties(${example} PROPERTIES LINK_FLAGS "${MPI_LINK_FLAGS}")
-        endif()
-        target_link_libraries(${example} ${MPI_CXX_LIBRARIES})
-    endforeach(example)
-endif()
-
 set(examples_to_install ${examples_to_install} ${all_advec_examples} PARENT_SCOPE)

tests/examples/advection_diffusion/CMakeLists.txt

@@ -27,25 +27,19 @@ if(${pfasst_WITH_MPI})
         if(MPI_COMPILE_FLAGS)
             if(pfasst_WITH_GCC_PROF AND ${CMAKE_CXX_COMPILER_ID} MATCHES GNU)
                 set_target_properties(${test}
-                    PROPERTIES COMPILE_FLAGS "${MPI_COMPILE_FLAGS} -ftest-coverage -fprofile-arcs"
+                    PROPERTIES COMPILE_FLAGS "-ftest-coverage -fprofile-arcs"
                                LINK_FLAGS "-fprofile-arcs"
                 )
-            else()
-                set_target_properties(${test} PROPERTIES COMPILE_FLAGS "${MPI_COMPILE_FLAGS}")
             endif()
         endif()
-        if(MPI_LINK_FLAGS)
-            set_target_properties(${test} PROPERTIES LINK_FLAGS "${MPI_LINK_FLAGS}")
-        endif()
         target_link_libraries(${test}
             ${3rdparty_DEPENDEND_LIBS}
             ${TESTS_3rdparty_DEPENDEND_LIBS}
             ${FFTW_LIBRARIES}
             ${pfasst_DEPENDEND_LIBS}
-            ${MPI_CXX_LIBRARIES}
         )
         add_test(NAME ${test}
-            COMMAND ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} 4 ${MPIEXEC_PREFLAGS} ${CMAKE_BINARY_DIR}/tests/examples/advection_diffusion/${test} ${MPIEXEC_POSTFLAGS} --gtest_output=xml:${test}_out.xml
+            COMMAND ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} 4 ${CMAKE_BINARY_DIR}/tests/examples/advection_diffusion/${test} --gtest_output=xml:${test}_out.xml
         )
     endforeach(test)
 else()