From be8b4aa9a48e10782c552c4371231fe47c4a1747 Mon Sep 17 00:00:00 2001
From: Michael Hirsch <scivision@users.noreply.github.com>
Date: Wed, 4 Aug 2021 11:50:48 -0400
Subject: [PATCH] FindMPI: avoid stripping repeated -Wl,rpath -Wl,/path/...

---
 cmake/Modules/FindMPI.cmake |  15 ++--
 dev/unit.cmake              | 132 ++++++++++++++++++++++++++++++++++++
 2 files changed, 139 insertions(+), 8 deletions(-)
 create mode 100644 dev/unit.cmake

diff --git a/cmake/Modules/FindMPI.cmake b/cmake/Modules/FindMPI.cmake
index d6e9300..0625fe7 100644
--- a/cmake/Modules/FindMPI.cmake
+++ b/cmake/Modules/FindMPI.cmake
@@ -104,16 +104,15 @@ if("${raw}" MATCHES "^/")
   endif()
 endif()
 
+# Linker flags "-Wl,..."
 string(REGEX MATCHALL "(^| )(-Wl,)([^\" ]+|\"[^\"]+\")" _Wflags "${raw}")
 list(TRANSFORM _Wflags STRIP)
 if(_Wflags)
-  set(CMAKE_C_LINKER_WRAPPER_FLAG "-Wl,")
-  set(CMAKE_C_LINKER_WRAPPER_FLAG_SEP ",")
-  set(CMAKE_CXX_LINKER_WRAPPER_FLAG "-Wl,")
-  set(CMAKE_CXX_LINKER_WRAPPER_FLAG_SEP ",")
-  set(CMAKE_Fortran_LINKER_WRAPPER_FLAG "-Wl,")
-  set(CMAKE_Fortran_LINKER_WRAPPER_FLAG_SEP ",")
-  list(APPEND _flags ${_Wflags})
+  # this transform avoids CMake stripping out all "-Wl,rpath" after first.
+  # Example:
+  #  -Wl,rpath -Wl,/path/to/lib -Wl,rpath -Wl,/path/to/another
+  list(TRANSFORM _Wflags REPLACE "-Wl," "LINKER:")
+  list(APPEND _flags "${_Wflags}")
 else()
   pop_flag("${raw}" -Xlinker _Xflags)
   if(_Xflags)
@@ -125,7 +124,7 @@ else()
   endif()
 endif()
 
-set(${outvar} ${_flags} PARENT_SCOPE)
+set(${outvar} "${_flags}" PARENT_SCOPE)
 
 endfunction(get_link_flags)
 
diff --git a/dev/unit.cmake b/dev/unit.cmake
new file mode 100644
index 0000000..da02d7b
--- /dev/null
+++ b/dev/unit.cmake
@@ -0,0 +1,132 @@
+# Unit tests for FindMPI.cmake
+
+function(get_flags exec outvar)
+
+execute_process(COMMAND ${exec} -show
+OUTPUT_STRIP_TRAILING_WHITESPACE
+OUTPUT_VARIABLE ret
+RESULT_VARIABLE code
+TIMEOUT 10
+)
+if(NOT code EQUAL 0)
+  return()
+endif()
+
+set(${outvar} ${ret} PARENT_SCOPE)
+
+endfunction(get_flags)
+
+
+function(get_link_flags raw outvar)
+
+
+string(REGEX MATCHALL "(^| )(${CMAKE_LIBRARY_PATH_FLAG})([^\" ]+|\"[^\"]+\")" _Lflags "${raw}")
+list(TRANSFORM _Lflags STRIP)
+set(_flags ${_Lflags})
+
+# check if compiler absolute path is first element and remove
+if("${raw}" MATCHES "^/")
+  if("${_flags}" MATCHES "^/")
+    list(REMOVE_AT _flags 0)
+  endif()
+endif()
+
+# Linker flags "-Wl,..."
+string(REGEX MATCHALL "(^| )(-Wl,)([^\" ]+|\"[^\"]+\")" _Wflags "${raw}")
+list(TRANSFORM _Wflags STRIP)
+if(_Wflags)
+  # this transform avoids CMake stripping out all "-Wl,rpath" after first.
+  # Example:
+  #  -Wl,rpath -Wl,/path/to/lib -Wl,rpath -Wl,/path/to/another
+  list(TRANSFORM _Wflags REPLACE "-Wl," "LINKER:")
+  list(APPEND _flags "${_Wflags}")
+else()
+  pop_flag("${raw}" -Xlinker _Xflags)
+  if(_Xflags)
+    set(CMAKE_C_LINKER_WRAPPER_FLAG "-Xlinker" " ")
+    set(CMAKE_CXX_LINKER_WRAPPER_FLAG "-Xlinker" " ")
+    set(CMAKE_Fortran_LINKER_WRAPPER_FLAG "-Xlinker" " ")
+    string(REPLACE ";" "," _Xflags "${_Xflags}")
+    list(APPEND _flags "LINKER:${_Xflags}")
+  endif()
+endif()
+
+set(${outvar} "${_flags}" PARENT_SCOPE)
+
+endfunction(get_link_flags)
+
+
+function(pop_flag raw flag outvar)
+# this gives the argument to flags to get their paths like -I or -l or -L
+
+set(_v)
+string(REGEX MATCHALL "(^| )${flag} *([^\" ]+|\"[^\"]+\")" _vars "${raw}")
+foreach(_p IN LISTS _vars)
+  string(REGEX REPLACE "(^| )${flag} *" "" _p "${_p}")
+  list(APPEND _v "${_p}")
+endforeach()
+
+set(${outvar} ${_v} PARENT_SCOPE)
+
+endfunction(pop_flag)
+
+
+function(pop_path raw outvar)
+# these are file paths without flags like /usr/lib/mpi.so
+
+if(MSVC)
+  return()
+endif()
+
+set(flag /)
+set(_v)
+string(REGEX MATCHALL "(^| )${flag} *([^\" ]+|\"[^\"]+\")" _vars "${raw}")
+foreach(_p IN LISTS _vars)
+  string(REGEX REPLACE "(^| )${flag} *" "" _p "${_p}")
+  list(APPEND _v "/${_p}")
+endforeach()
+
+# check if compiler absolute path is first element and remove
+if("${raw}" MATCHES "^/")
+  list(REMOVE_AT _v 0)
+endif()
+
+set(${outvar} ${_v} PARENT_SCOPE)
+
+endfunction(pop_path)
+
+
+# ---- tests ----
+
+set(CMAKE_LIBRARY_PATH_FLAG -L)
+
+# Cray mpifort -show
+function(cray_fortran)
+set(f_raw "gfortran -I/cm/shared/apps/openmpi/gcc/64/3.1.2_gcc8/include -pthread -I/cm/shared/apps/openmpi/gcc/64/3.1.2_gcc8/lib -L/usr/lib64 -L/opt/mellanox/mxm/lib -Wl,-rpath -Wl,/usr/lib64 -Wl,-rpath -Wl,/opt/mellanox/mxm/lib -Wl,-rpath -Wl,/cm/shared/apps/openmpi/gcc/64/3.1.2_gcc8/lib -Wl,--enable-new-dtags -L/cm/shared/apps/openmpi/gcc/64/3.1.2_gcc8/lib -lmpi_usempif08 -lmpi_usempi_ignore_tkr -lmpi_mpifh -lmpi")
+
+pop_flag(${f_raw} -I inc_dirs)
+pop_flag(${f_raw} ${CMAKE_LIBRARY_PATH_FLAG} lib_dirs)
+
+pop_flag(${f_raw} -l lib_names)
+
+pop_path(${f_raw} lib_paths)
+
+get_link_flags(${f_raw} MPI_Fortran_LINK_FLAGS)
+
+# Cray unit test
+if(lib_paths)
+  message(FATAL_ERROR "lib_paths not present in Cray mpifort -show")
+endif()
+
+set(MPI_Fortran_LINK_FLAGS "${MPI_Fortran_LINK_FLAGS}" PARENT_SCOPE)
+endfunction(cray_fortran)
+
+cray_fortran()
+
+message(STATUS "
+MPI_Fortran_INCLUDE_DIR: ${inc_dirs}
+MPI_Fortran_LIBRARY_DIR: ${lib_dirs}
+MPI_Fortran_LIBRARY_NAMES: ${lib_names}
+MPI_Fortran_LIBRARY: ${lib_paths}
+MPI_Fortran_LINK_FLAGS: ${MPI_Fortran_LINK_FLAGS}
+")