Backport FindSWIG and UseSWIG from upstream

Author: sethrj

CMakeLists.txt

@@ -80,7 +80,7 @@ if (CMAKE_VERSION VERSION_LESS 3.18)
 endif()
 
 if (FLIBCPP_USE_SWIG)
-  find_package(SWIG REQUIRED)
+  find_package(SWIG COMPONENTS fortran REQUIRED)
 
   if (CMAKE_VERSION VERSION_LESS 3.12)
     message(FATAL_ERROR "CMake 3.12 or higher is required to regenerate the "

cmake/CheckSWIGFortran.cmake

@@ -0,0 +1,110 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#[=======================================================================[.rst:
+FindSWIG
+--------
+
+Find the Simplified Wrapper and Interface Generator (SWIG_) executable.
+
+
+This module finds an installed SWIG and determines its version. If a
+``COMPONENTS`` or ``OPTIONAL_COMPONENTS`` argument is given to ``find_package``,
+it will also determine supported target languages.  The module sents the
+following variables:
+
+``SWIG_FOUND``
+  Whether SWIG and any required components were found on the system.
+``SWIG_EXECUTABLE``
+  Path to the SWIG executable.
+``SWIG_DIR``
+  Path to the installed SWIG ``Lib`` directory (result of ``swig -swiglib``).
+``SWIG_VERSION``
+  SWIG executable version (result of ``swig -version``).
+``SWIG_<lang>_FOUND``
+  If ``COMPONENTS`` or ``OPTIONAL_COMPONENTS`` are requested, each available
+  target language ``<lang>`` (lowercase) will be set to TRUE.
+
+Any ``COMPONENTS`` given to ``find_package`` should be the names of supported
+target languages as provided to the LANGUAGE argument of ``swig_add_library``,
+such as ``python`` or ``perl5``. Language names *must* be lowercase.
+
+All information is collected from the ``SWIG_EXECUTABLE``, so the version
+to be found can be changed from the command line by means of setting
+``SWIG_EXECUTABLE``.
+
+Example usage requiring SWIG 4.0 or higher and Python language support, with
+optional Fortran support:
+
+.. code-block:: cmake
+
+   find_package(SWIG 4.0 COMPONENTS python OPTIONAL_COMPONENTS fortran)
+   if(SWIG_FOUND)
+     message("SWIG found: ${SWIG_EXECUTABLE}")
+     if(NOT SWIG_fortran_FOUND)
+       message(WARNING "SWIG Fortran bindings cannot be generated")
+     endif()
+   endif()
+
+.. _`SWIG`: http://swig.org
+
+#]=======================================================================]
+
+find_program(SWIG_EXECUTABLE NAMES swig4.0 swig3.0 swig2.0 swig)
+
+if(SWIG_EXECUTABLE)
+  execute_process(COMMAND ${SWIG_EXECUTABLE} -swiglib
+    OUTPUT_VARIABLE SWIG_swiglib_output
+    ERROR_VARIABLE SWIG_swiglib_error
+    RESULT_VARIABLE SWIG_swiglib_result)
+
+  if(SWIG_swiglib_result)
+    if(SWIG_FIND_REQUIRED)
+      message(SEND_ERROR "Command \"${SWIG_EXECUTABLE} -swiglib\" failed with output:\n${SWIG_swiglib_error}")
+    else()
+      message(STATUS "Command \"${SWIG_EXECUTABLE} -swiglib\" failed with output:\n${SWIG_swiglib_error}")
+    endif()
+  else()
+    string(REGEX REPLACE "[\n\r]+" ";" SWIG_swiglib_output ${SWIG_swiglib_output})
+    find_path(SWIG_DIR swig.swg PATHS ${SWIG_swiglib_output} NO_CMAKE_FIND_ROOT_PATH)
+    if(SWIG_DIR)
+      set(SWIG_USE_FILE ${CMAKE_CURRENT_LIST_DIR}/UseSWIG.cmake)
+      execute_process(COMMAND ${SWIG_EXECUTABLE} -version
+        OUTPUT_VARIABLE SWIG_version_output
+        ERROR_VARIABLE SWIG_version_output
+        RESULT_VARIABLE SWIG_version_result)
+      if(SWIG_version_result)
+        message(SEND_ERROR "Command \"${SWIG_EXECUTABLE} -version\" failed with output:\n${SWIG_version_output}")
+      else()
+        string(REGEX REPLACE ".*SWIG Version[^0-9.]*\([0-9.]+\).*" "\\1"
+          SWIG_version_output "${SWIG_version_output}")
+        set(SWIG_VERSION ${SWIG_version_output} CACHE STRING "Swig version" FORCE)
+      endif()
+    endif()
+  endif()
+
+  if(SWIG_FIND_COMPONENTS)
+    execute_process(COMMAND ${SWIG_EXECUTABLE} -help
+      OUTPUT_VARIABLE SWIG_swighelp_output
+      ERROR_VARIABLE SWIG_swighelp_error
+      RESULT_VARIABLE SWIG_swighelp_result)
+    if(SWIG_swighelp_result)
+      message(SEND_ERROR "Command \"${SWIG_EXECUTABLE} -help\" failed with output:\n${SWIG_swiglib_error}")
+    else()
+      string(REPLACE "\n" ";" SWIG_swighelp_output "${SWIG_swighelp_output}")
+      foreach(SWIG_line IN LISTS SWIG_swighelp_output)
+        if(SWIG_line MATCHES "-([A-Za-z0-9_]+) +- *Generate.*wrappers")
+          set(SWIG_${CMAKE_MATCH_1}_FOUND TRUE)
+        endif()
+      endforeach()
+    endif()
+  endif()
+endif()
+
+include(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)
+find_package_handle_standard_args(
+  SWIG HANDLE_COMPONENTS
+  REQUIRED_VARS SWIG_EXECUTABLE SWIG_DIR
+  VERSION_VAR SWIG_VERSION)
+
+mark_as_advanced(SWIG_DIR SWIG_VERSION SWIG_EXECUTABLE)

cmake/backport-cmake-318/FindSWIG.cmake

@@ -234,15 +234,27 @@ as well as ``SWIG``:
     set(SWIG_SOURCE_FILE_EXTENSIONS ".i" ".swg")
 #]=======================================================================]
 
+cmake_policy(GET CMP0078 target_name_policy)
+cmake_policy(GET CMP0086 module_name_policy)
+
 cmake_policy (VERSION 3.12)
+if (target_name_policy)
+  # respect user choice regarding CMP0078 policy
+  cmake_policy(SET CMP0078 ${target_name_policy})
+endif()
+if (module_name_policy)
+  # respect user choice regarding CMP0086 policy
+  cmake_policy(SET CMP0086 ${module_name_policy})
+endif()
+unset(target_name_policy)
+unset(module_name_policy)
 
 set(SWIG_CXX_EXTENSION "cxx")
 set(SWIG_EXTRA_LIBRARIES "")
 
 set(SWIG_PYTHON_EXTRA_FILE_EXTENSIONS ".py")
 set(SWIG_JAVA_EXTRA_FILE_EXTENSIONS ".java" "JNI.java")
 set(SWIG_CSHARP_EXTRA_FILE_EXTENSIONS ".cs" "PINVOKE.cs")
-set(SWIG_FORTRAN_EXTRA_FILE_EXTENSIONS ".f90")
 
 set(SWIG_MANAGE_SUPPORT_FILES_SCRIPT "${CMAKE_CURRENT_LIST_DIR}/UseSWIG/ManageSupportFiles.cmake")
 
@@ -322,15 +334,30 @@ function(SWIG_GET_EXTRA_OUTPUT_FILES language outfiles generatedpath infile)
     set(extra_file "${generatedpath}/${module_basename}${it}")
     if (extra_file MATCHES "\\.cs$" AND CMAKE_CSharp_COMPILER_LOADED)
       set_source_files_properties(${extra_file} PROPERTIES LANGUAGE "CSharp")
-    elseif (extra_file MATCHES "\\.f90$" AND CMAKE_Fortran_COMPILER_LOADED)
-      set_source_files_properties(${extra_file} PROPERTIES LANGUAGE "Fortran")
     else()
       # Treat extra outputs as plain files regardless of language.
       set_source_files_properties(${extra_file} PROPERTIES LANGUAGE "")
     endif()
     list(APPEND files "${extra_file}")
   endforeach()
 
+  if (language STREQUAL "FORTRAN" AND CMAKE_Fortran_COMPILER_LOADED)
+    # Process possible user-supplied extension in flags (obtained via parent
+    # scope variable) to determine the source file name.
+    list(FIND SWIG_COMPILATION_FLAGS "-fext" fext_idx)
+    if (fext_idx EQUAL -1)
+      # Default Fortran generated extension
+      set(fext "f90")
+    else()
+      # Get extension from user-provided flag
+      math(EXPR fext_idx "${fext_idx} + 1")
+      list(GET SWIG_COMPILATION_FLAGS "${fext_idx}" fext)
+    endif()
+    set(extra_file "${generatedpath}/${module_basename}.${fext}")
+    set_source_files_properties("${extra_file}" PROPERTIES LANGUAGE "Fortran")
+    list(APPEND files "${extra_file}")
+  endif()
+
   set (${outfiles} ${files} PARENT_SCOPE)
 endfunction()
 
@@ -405,6 +432,7 @@ function(SWIG_ADD_SOURCE_TO_MODULE name outfiles infile)
   get_filename_component(swig_source_file_fullname "${infile}" ABSOLUTE)
 
   if (NOT SWIG_MODULE_${name}_NOPROXY)
+    set(SWIG_COMPILATION_FLAGS ${swig_source_file_flags})
     SWIG_GET_EXTRA_OUTPUT_FILES(${SWIG_MODULE_${name}_LANGUAGE}
       swig_extra_generated_files
       "${outdir}"
@@ -438,20 +466,32 @@ function(SWIG_ADD_SOURCE_TO_MODULE name outfiles infile)
     list (APPEND swig_special_flags "-c++")
   endif()
 
-  set(module_name_policy "NEW")
+  cmake_policy(GET CMP0086 module_name_policy)
   if (module_name_policy STREQUAL "NEW")
     get_source_file_property(module_name "${infile}" SWIG_MODULE_NAME)
     if (module_name)
       list (APPEND swig_special_flags "-module" "${module_name}")
     endif()
+  else()
+    if (NOT module_name_policy)
+      cmake_policy(GET_WARNING CMP0086 _cmp0086_warning)
+      message(AUTHOR_WARNING "${_cmp0086_warning}\n")
+    endif()
   endif()
 
   set (swig_extra_flags)
   if(SWIG_MODULE_${name}_LANGUAGE STREQUAL "CSHARP")
     if(NOT ("-dllimport" IN_LIST swig_source_file_flags OR "-dllimport" IN_LIST SWIG_MODULE_${name}_EXTRA_FLAGS))
       # This makes sure that the name used in the generated DllImport
       # matches the library name created by CMake
-      list (APPEND SWIG_MODULE_${name}_EXTRA_FLAGS "-dllimport" "${name}")
+      list (APPEND SWIG_MODULE_${name}_EXTRA_FLAGS "-dllimport" "$<TARGET_FILE_PREFIX:${target_name}>$<TARGET_FILE_BASE_NAME:${target_name}>")
+    endif()
+  endif()
+  if (SWIG_MODULE_${name}_LANGUAGE STREQUAL "PYTHON" AND NOT SWIG_MODULE_${name}_NOPROXY)
+    if(NOT ("-interface" IN_LIST swig_source_file_flags OR "-interface" IN_LIST SWIG_MODULE_${name}_EXTRA_FLAGS))
+      # This makes sure that the name used in the proxy code
+      # matches the library name created by CMake
+      list (APPEND SWIG_MODULE_${name}_EXTRA_FLAGS "-interface" "$<TARGET_FILE_PREFIX:${target_name}>$<TARGET_FILE_BASE_NAME:${target_name}>")
     endif()
   endif()
   list (APPEND swig_extra_flags ${SWIG_MODULE_${name}_EXTRA_FLAGS})
@@ -576,11 +616,12 @@ function(SWIG_ADD_LIBRARY name)
     unset(_SAM_TYPE)
   endif()
 
-  set(target_name_policy "NEW")
+  cmake_policy(GET CMP0078 target_name_policy)
   if (target_name_policy STREQUAL "NEW")
     set (UseSWIG_TARGET_NAME_PREFERENCE STANDARD)
   else()
     if (NOT target_name_policy)
+      cmake_policy(GET_WARNING CMP0078 _cmp0078_warning)
       message(AUTHOR_WARNING "${_cmp0078_warning}\n")
     endif()
     if (NOT DEFINED UseSWIG_TARGET_NAME_PREFERENCE)
@@ -685,9 +726,9 @@ function(SWIG_ADD_LIBRARY name)
     endif()
   endforeach()
   set_property (DIRECTORY APPEND PROPERTY
-    ADDITIONAL_MAKE_CLEAN_FILES ${swig_generated_sources} ${swig_generated_timestamps})
+    ADDITIONAL_CLEAN_FILES ${swig_generated_sources} ${swig_generated_timestamps})
   if (UseSWIG_MODULE_VERSION VERSION_GREATER 1)
-    set_property (DIRECTORY APPEND PROPERTY ADDITIONAL_MAKE_CLEAN_FILES "${outputdir}")
+    set_property (DIRECTORY APPEND PROPERTY ADDITIONAL_CLEAN_FILES "${outputdir}")
   endif()
 
   add_library(${target_name}
@@ -706,8 +747,6 @@ function(SWIG_ADD_LIBRARY name)
   if (swig_lowercase_language STREQUAL "octave")
     set_target_properties(${target_name} PROPERTIES PREFIX "")
     set_target_properties(${target_name} PROPERTIES SUFFIX ".oct")
-  elseif (swig_lowercase_language STREQUAL "fortran")
-    # XXX
   elseif (swig_lowercase_language STREQUAL "go")
     set_target_properties(${target_name} PROPERTIES PREFIX "")
   elseif (swig_lowercase_language STREQUAL "java")
@@ -766,6 +805,8 @@ function(SWIG_ADD_LIBRARY name)
     if (APPLE)
       set_target_properties (${target_name} PROPERTIES SUFFIX ".dylib")
     endif ()
+  elseif (swig_lowercase_language STREQUAL "fortran")
+    # Do *not* override the target's library prefix
   else()
     # assume empty prefix because we expect the module to be dynamically loaded
     set_target_properties (${target_name} PROPERTIES PREFIX "")

cmake/UseSWIGFortran.cmake renamed to cmake/backport-cmake-318/UseSWIG.cmake

@@ -0,0 +1,31 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+
+if (ACTION STREQUAL "CLEAN")
+  # Collect current list of generated files
+  file (GLOB files LIST_DIRECTORIES FALSE RELATIVE "${SUPPORT_FILES_WORKING_DIRECTORY}" "${SUPPORT_FILES_WORKING_DIRECTORY}/*")
+
+  if (files)
+    # clean-up the output directory
+    ## compute full paths
+    list (TRANSFORM files PREPEND "${SUPPORT_FILES_OUTPUT_DIRECTORY}/")
+    ## remove generated files from the output directory
+    file (REMOVE ${files})
+
+    # clean-up working directory
+    file (REMOVE_RECURSE "${SUPPORT_FILES_WORKING_DIRECTORY}")
+  endif()
+
+  file (MAKE_DIRECTORY "${SUPPORT_FILES_WORKING_DIRECTORY}")
+endif()
+
+if (ACTION STREQUAL "COPY")
+  # Collect current list of generated files
+  file (GLOB files LIST_DIRECTORIES FALSE "${SUPPORT_FILES_WORKING_DIRECTORY}/*")
+
+  if (files)
+    # copy files to the output directory
+    file (COPY ${files} DESTINATION "${SUPPORT_FILES_OUTPUT_DIRECTORY}")
+  endif()
+endif()