FindMPI: Move MSMPI/MPICH2 mpiexec search

Move the logic to search mpiexec for MSMPI and MPICH2 guesses to their
respective guessing logic. This way, we can prevent mix ups between
their mpiexecs and other potential matches, for example from an Intel
MPI installation.

1 files changed, 45 insertions, 15 deletions

diff --git a/Modules/FindMPI.cmake b/Modules/FindMPI.cmake
index db14a89..c5eabbb 100644
--- a/Modules/FindMPI.cmake
+++ b/Modules/FindMPI.cmake
@@ -744,13 +744,22 @@ function(_MPI_guess_settings LANG)
         endif()
         mark_as_advanced(MPI_${LANG}_LIB_NAMES)
         set(MPI_GUESS_FOUND TRUE)
+
+        if(_MPIEXEC_NOT_GIVEN)
+          unset(MPIEXEC_EXECUTABLE CACHE)
+        endif()
+
+        find_program(MPIEXEC_EXECUTABLE
+          NAMES mpiexec
+          HINTS $ENV{MSMPI_BIN} "[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\MPI;InstallRoot]/Bin"
+          DOC "Executable for running MPI programs.")
       endif()
     endif()
 
     # At this point there's not many MPIs that we could still consider.
     # OpenMPI 1.6.x and below supported Windows, but these ship compiler wrappers that still work.
     # The only other relevant MPI implementation without a wrapper is MPICH2, which had Windows support in 1.4.1p1 and older.
-    if(NOT MPI_GUESS_LIBRARY_NAME OR "${MPI_GUESS_LIBRARY_NAME}" STREQUAL "MPICH2")
+    if(NOT MPI_GUESS_FOUND AND (NOT MPI_GUESS_LIBRARY_NAME OR "${MPI_GUESS_LIBRARY_NAME}" STREQUAL "MPICH2"))
       set(MPI_MPICH_PREFIX_PATHS
         "$ENV{ProgramW6432}/MPICH2/lib"
         "[HKEY_LOCAL_MACHINE\\SOFTWARE\\MPICH\\SMPD;binary]/../lib"
@@ -809,6 +818,17 @@ function(_MPI_guess_settings LANG)
           unset(MPI_MPICH_ROOT_DIR)
         endif()
         set(MPI_GUESS_FOUND TRUE)
+
+        if(_MPIEXEC_NOT_GIVEN)
+          unset(MPIEXEC_EXECUTABLE CACHE)
+        endif()
+
+        find_program(MPIEXEC_EXECUTABLE
+          NAMES ${_MPIEXEC_NAMES}
+          HINTS "$ENV{ProgramW6432}/MPICH2/bin"
+                "[HKEY_LOCAL_MACHINE\\SOFTWARE\\MPICH\\SMPD;binary]"
+                "[HKEY_LOCAL_MACHINE\\SOFTWARE\\MPICH2;Path]/bin"
+          DOC "Executable for running MPI programs.")
       endif()
       unset(MPI_MPICH_PREFIX_PATHS)
     endif()
@@ -1034,9 +1054,6 @@ if("${CMAKE_HOST_SYSTEM_NAME}" STREQUAL "Linux")
   # SUSE Linux Enterprise Server stores its MPI implementations under /usr/lib64/mpi/gcc/<name>
   # We enumerate the subfolders and append each as a prefix
   MPI_search_mpi_prefix_folder("/usr/lib64/mpi/gcc")
-elseif("${CMAKE_HOST_SYSTEM_NAME}" STREQUAL "Windows")
-  # MSMPI stores its runtime in a special folder, this adds the possible locations to the hints.
-  list(APPEND MPI_HINT_DIRS $ENV{MSMPI_BIN} "[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\MPI;InstallRoot]")
 elseif("${CMAKE_HOST_SYSTEM_NAME}" STREQUAL "FreeBSD")
   # FreeBSD ships mpich under the normal system paths - but available openmpi implementations
   # will be found in /usr/local/mpi/<name>
@@ -1046,6 +1063,15 @@ endif()
 # Most MPI distributions have some form of mpiexec or mpirun which gives us something we can look for.
 # The MPI standard does not mandate the existence of either, but instead only makes requirements if a distribution
 # ships an mpiexec program (mpirun executables are not regulated by the standard).
+
+# We defer searching for mpiexec binaries belonging to guesses until later. By doing so, mismatches between mpiexec
+# and the MPI we found should be reduced.
+if(NOT MPIEXEC_EXECUTABLE)
+  set(_MPIEXEC_NOT_GIVEN TRUE)
+else()
+  set(_MPIEXEC_NOT_GIVEN FALSE)
+endif()
+
 find_program(MPIEXEC_EXECUTABLE
   NAMES ${_MPIEXEC_NAMES}
   PATH_SUFFIXES bin sbin
@@ -1233,17 +1259,21 @@ foreach(LANG IN ITEMS C CXX Fortran)
           endif()
         endif()
 
-        if(NOT MPI_SKIP_GUESSING AND NOT MPI_${LANG}_WRAPPER_FOUND AND NOT MPI_PINNED_COMPILER)
-          # For C++, we may use the settings for C. Should a given compiler wrapper for C++ not exist, but one for C does, we copy over the
-          # settings for C. An MPI distribution that is in this situation would be IBM Platform MPI.
-          if("${LANG}" STREQUAL "CXX" AND MPI_C_WRAPPER_FOUND)
-            set(MPI_${LANG}_COMPILE_OPTIONS          ${MPI_C_COMPILE_OPTIONS}     CACHE STRING "MPI ${LANG} compilation options"           )
-            set(MPI_${LANG}_COMPILE_DEFINITIONS      ${MPI_C_COMPILE_DEFINITIONS} CACHE STRING "MPI ${LANG} compilation definitions"       )
-            set(MPI_${LANG}_ADDITIONAL_INCLUDE_DIRS  ${MPI_C_INCLUDE_DIRS}        CACHE STRING "MPI ${LANG} additional include directories")
-            set(MPI_${LANG}_LINK_FLAGS               ${MPI_C_LINK_FLAGS}          CACHE STRING "MPI ${LANG} linker flags"                  )
-            set(MPI_${LANG}_LIB_NAMES                ${MPI_C_LIB_NAMES}           CACHE STRING "MPI ${LANG} libraries to link against"     )
-          else()
-            _MPI_guess_settings(${LANG})
+        if(NOT MPI_PINNED_COMPILER AND NOT MPI_${LANG}_WRAPPER_FOUND)
+          # If MPI_PINNED_COMPILER wasn't given, and the MPI compiler we potentially found didn't work, we withdraw it.
+          set(MPI_${LANG}_COMPILER "MPI_${LANG}_COMPILER-NOTFOUND" CACHE FILEPATH "MPI compiler for ${LANG}" FORCE)
+          if(NOT MPI_SKIP_GUESSING)
+            # For C++, we may use the settings for C. Should a given compiler wrapper for C++ not exist, but one for C does, we copy over the
+            # settings for C. An MPI distribution that is in this situation would be IBM Platform MPI.
+            if("${LANG}" STREQUAL "CXX" AND MPI_C_WRAPPER_FOUND)
+              set(MPI_${LANG}_COMPILE_OPTIONS          ${MPI_C_COMPILE_OPTIONS}     CACHE STRING "MPI ${LANG} compilation options"           )
+              set(MPI_${LANG}_COMPILE_DEFINITIONS      ${MPI_C_COMPILE_DEFINITIONS} CACHE STRING "MPI ${LANG} compilation definitions"       )
+              set(MPI_${LANG}_ADDITIONAL_INCLUDE_DIRS  ${MPI_C_INCLUDE_DIRS}        CACHE STRING "MPI ${LANG} additional include directories")
+              set(MPI_${LANG}_LINK_FLAGS               ${MPI_C_LINK_FLAGS}          CACHE STRING "MPI ${LANG} linker flags"                  )
+              set(MPI_${LANG}_LIB_NAMES                ${MPI_C_LIB_NAMES}           CACHE STRING "MPI ${LANG} libraries to link against"     )
+            else()
+              _MPI_guess_settings(${LANG})
+            endif()
           endif()
         endif()
       endif()