Try simultaneous compilation of serial and MPI executables

CMakeLists.txt

@@ -6,37 +6,31 @@ project(
     LANGUAGES Fortran
 )
 
-option(CABLE_MPI "Build the MPI executable" OFF)
-
 # third party libs
+find_package(MPI REQUIRED)
 find_package(PkgConfig REQUIRED)
 pkg_check_modules(NETCDF REQUIRED IMPORTED_TARGET "netcdf-fortran")
-if(CABLE_MPI)
-    find_package(MPI REQUIRED)
-endif()
+set(
+    CABLE_LINK_LIBRARIES
+    PkgConfig::NETCDF
+    MPI::MPI_Fortran
+)
 
 set(CABLE_INTEL_Fortran_FLAGS -fp-model precise)
 set(CABLE_INTEL_Fortran_FLAGS_DEBUG -O0 -g -traceback -fpe0)
 set(CABLE_INTEL_Fortran_FLAGS_RELEASE -O2)
+if(CMAKE_Fortran_COMPILER_ID MATCHES "Intel")
+    set(
+        CABLE_Fortran_FLAGS
+        ${CABLE_INTEL_Fortran_FLAGS}
+        "$<$<CONFIG:Release>:${CABLE_INTEL_Fortran_FLAGS_RELEASE}>"
+        "$<$<CONFIG:Debug>:${CABLE_INTEL_Fortran_FLAGS_DEBUG}>"
+    )
+endif()
 
-# CMake $<...> syntax is explained here:
-# https://cmake.org/cmake/help/latest/manual/cmake-generator-expressions.7.html#introduction
-set(CABLE_EXE_NAME "$<IF:$<BOOL:${CABLE_MPI}>,cable-mpi,cable>")
-
-set(
-    CABLE_SRCS_SERIAL
-    src/offline/cable_driver.F90
-)
-set(
-    CABLE_SRCS_MPI
-    src/offline/cable_mpidrv.F90
-    src/offline/cable_mpicommon.F90
-    src/offline/cable_mpimaster.F90
-    src/offline/cable_mpiworker.F90
-    src/science/pop/pop_mpi.F90
-)
-set(
-    CABLE_SRCS_COMMON
+add_library(
+    cable_common_objlib
+    OBJECT
     src/science/casa-cnp/bgcdriver.F90
     src/science/casa-cnp/biogeochem_casa.F90
     src/offline/cable_abort.F90
@@ -146,30 +140,27 @@ set(
     src/science/roughness/roughnessHGT_effLAI_cbl.F90
     src/offline/spincasacnp.F90
 )
-set(
-    CABLE_SRCS
-    "$<IF:$<BOOL:${CABLE_MPI}>,${CABLE_SRCS_MPI},${CABLE_SRCS_SERIAL}>"
-    ${CABLE_SRCS_COMMON}
-)
+target_compile_options(cable_common_objlib PRIVATE ${CABLE_Fortran_FLAGS})
+target_link_libraries(cable_common_objlib ${CABLE_LINK_LIBRARIES})
 
-add_executable(cable ${CABLE_SRCS})
-
-set_target_properties(cable PROPERTIES OUTPUT_NAME ${CABLE_EXE_NAME})
-
-if(CMAKE_Fortran_COMPILER_ID MATCHES "Intel")
-    target_compile_options(
-        cable
-        PRIVATE
-        ${CABLE_INTEL_Fortran_FLAGS}
-        "$<$<CONFIG:Release>:${CABLE_INTEL_Fortran_FLAGS_RELEASE}>"
-        "$<$<CONFIG:Debug>:${CABLE_INTEL_Fortran_FLAGS_DEBUG}>"
-    )
-endif()
-
-target_link_libraries(
+add_executable(
     cable
-    PkgConfig::NETCDF
-    "$<$<BOOL:${CABLE_MPI}>:MPI::MPI_Fortran>"
+    src/offline/cable_driver.F90
+    "$<TARGET_OBJECTS:cable_common_objlib>"
+)
+target_compile_options(cable PRIVATE ${CABLE_Fortran_FLAGS})
+target_link_libraries(cable ${CABLE_LINK_LIBRARIES})
+
+add_executable(
+    cable-mpi
+    src/offline/cable_mpidrv.F90
+    src/offline/cable_mpicommon.F90
+    src/offline/cable_mpimaster.F90
+    src/offline/cable_mpiworker.F90
+    src/science/pop/pop_mpi.F90
+    "$<TARGET_OBJECTS:cable_common_objlib>"
 )
+target_compile_options(cable-mpi PRIVATE ${CABLE_Fortran_FLAGS})
+target_link_libraries(cable-mpi ${CABLE_LINK_LIBRARIES})
 
-install(TARGETS cable RUNTIME)
+install(TARGETS cable cable-mpi RUNTIME)

build.bash

@@ -8,7 +8,6 @@ Build script wrapper around CMake.
 
 Options:
       --clean   Delete build directory before invoking CMake.
-      --mpi     Compile MPI executable.
   -d, --debug   Compile in debug mode.
   -v, --verbose Enable verbose output when building the project.
   -h, --help    Show this screen.
@@ -22,9 +21,6 @@ while [ $# -gt 0 ]; do
         --clean)
             clean=1
             ;;
-        --mpi)
-            mpi=1
-            ;;
         -d|--debug)
             debug=1
             ;;
@@ -45,15 +41,13 @@ done
 if hostname -f | grep gadi.nci.org.au > /dev/null; then
     module purge
     module add intel-compiler/2019.5.281
+    module add intel-mpi/2019.5.281
     module add netcdf/4.6.3
     # This is required so that the netcdf-fortran library is discoverable by
     # pkg-config (Note, we manually prepend to PKG_CONFIG_PATH instead of
     # using `module prepend-path` so that we can invoke this script successfully
     # in benchcab):
     export PKG_CONFIG_PATH="${NETCDF_BASE}/lib/Intel/pkgconfig/:${PKG_CONFIG_PATH}"
-    if [[ -n $mpi ]]; then
-        module add intel-mpi/2019.5.281
-    fi
 fi
 
 if [[ -n $clean ]]; then
@@ -66,10 +60,8 @@ if [[ -n $debug ]]; then
 else
     cmake_args+=(-DCMAKE_BUILD_TYPE=Release)
 fi
-if [[ -n $mpi ]]; then
-    cmake_args+=(-DCABLE_MPI="ON")
-    cmake_args+=(-DMPI_Fortran_COMPILER="mpif90")
-fi
+
+cmake_args+=(-DMPI_Fortran_COMPILER="mpif90")
 
 cmake_build_args=()
 if [[ -n $verbose ]]; then