CMake/Modules/FortranCInterface/Detect.cmake

# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

configure_file(${FortranCInterface_SOURCE_DIR}/Input.cmake.in
               ${FortranCInterface_BINARY_DIR}/Input.cmake @ONLY)

# Detect the Fortran/C interface on the first run or when the
# configuration changes.
if(NOT EXISTS ${FortranCInterface_BINARY_DIR}/Output.cmake
    OR NOT EXISTS ${FortranCInterface_BINARY_DIR}/Input.cmake
    OR NOT ${FortranCInterface_BINARY_DIR}/Output.cmake
      IS_NEWER_THAN ${FortranCInterface_BINARY_DIR}/Input.cmake
    OR NOT ${FortranCInterface_BINARY_DIR}/Output.cmake
      IS_NEWER_THAN ${FortranCInterface_SOURCE_DIR}/Output.cmake.in
    OR NOT ${FortranCInterface_BINARY_DIR}/Output.cmake
      IS_NEWER_THAN ${FortranCInterface_SOURCE_DIR}/CMakeLists.txt
    OR NOT ${FortranCInterface_BINARY_DIR}/Output.cmake
      IS_NEWER_THAN ${CMAKE_CURRENT_LIST_FILE}
    )
  message(CHECK_START "Detecting Fortran/C Interface")
else()
  return()
endif()

# Invalidate verification results.
unset(FortranCInterface_VERIFIED_C CACHE)
unset(FortranCInterface_VERIFIED_CXX CACHE)

set(_result)

# Perform detection with only one architecture so that
# the info strings are not repeated.
if(CMAKE_OSX_ARCHITECTURES MATCHES "^([^;]+)(;|$)")
  set(_FortranCInterface_OSX_ARCH "-DCMAKE_OSX_ARCHITECTURES=${CMAKE_MATCH_1}")
else()
  set(_FortranCInterface_OSX_ARCH "")
endif()

set(_FortranCInterface_EXE_LINKER_FLAGS "-DCMAKE_EXE_LINKER_FLAGS:STRING=${CMAKE_EXE_LINKER_FLAGS}")

# Build a sample project which reports symbols.
set(CMAKE_TRY_COMPILE_CONFIGURATION Release)
try_compile(FortranCInterface_COMPILED
  PROJECT FortranCInterface
  TARGET FortranCInterface
  SOURCE_DIR ${FortranCInterface_SOURCE_DIR}
  BINARY_DIR ${FortranCInterface_BINARY_DIR}
  LOG_DESCRIPTION "Fortran/C interface test project"
  CMAKE_FLAGS
    "-DCMAKE_C_FLAGS:STRING=${CMAKE_C_FLAGS}"
    "-DCMAKE_Fortran_FLAGS:STRING=${CMAKE_Fortran_FLAGS}"
    "-DCMAKE_C_FLAGS_RELEASE:STRING=${CMAKE_C_FLAGS_RELEASE}"
    "-DCMAKE_Fortran_FLAGS_RELEASE:STRING=${CMAKE_Fortran_FLAGS_RELEASE}"
    ${_FortranCInterface_OSX_ARCH}
    ${_FortranCInterface_EXE_LINKER_FLAGS}
  )
set(FortranCInterface_COMPILED ${FortranCInterface_COMPILED})
unset(FortranCInterface_COMPILED CACHE)
unset(_FortranCInterface_EXE_LINKER_FLAGS)
unset(_FortranCInterface_OSX_ARCH)

# Locate the sample project executable.
set(FortranCInterface_EXE)
if(FortranCInterface_COMPILED)
  include(${FortranCInterface_BINARY_DIR}/exe-Release.cmake OPTIONAL)
else()
  set(_result "Failed to compile")
endif()

# Load symbols from INFO:symbol[] strings in the executable.
set(FortranCInterface_SYMBOLS)
if(FortranCInterface_EXE)
  cmake_policy(PUSH)
  cmake_policy(SET CMP0159 NEW) # file(STRINGS) with REGEX updates CMAKE_MATCH_<n>
  file(STRINGS "${FortranCInterface_EXE}" _info_strings
    LIMIT_COUNT 8 REGEX "INFO:[A-Za-z0-9_]+\\[[^]]*\\]")
  cmake_policy(POP)
  foreach(info ${_info_strings})
    if("${info}" MATCHES "INFO:symbol\\[([^]]*)\\]")
      list(APPEND FortranCInterface_SYMBOLS ${CMAKE_MATCH_1})
    endif()
  endforeach()
elseif(NOT _result)
  set(_result "Failed to load sample executable")
endif()

set(_case_mysub "LOWER")
set(_case_my_sub "LOWER")
set(_case_MYSUB "UPPER")
set(_case_MY_SUB "UPPER")
set(_global_regex  "^(_*)(mysub|MYSUB)([_$]*)$")
set(_global__regex "^(_*)(my_sub|MY_SUB)([_$]*)$")
set(_module_regex "^([A-Za-z_$]*)(mymodule|MYMODULE)([A-Za-z_$]*)(mysub|MYSUB)([_$]*)$")
set(_module__regex "^([A-Za-z_$]*)(my_module|MY_MODULE)([A-Za-z_$]*)(my_sub|MY_SUB)([_$]*)$")

# Parse the symbol names.
foreach(symbol ${FortranCInterface_SYMBOLS})
  foreach(form "" "_")
    # Look for global symbols.
    string(REGEX REPLACE "${_global_${form}regex}"
                         "\\1;\\2;\\3" pieces "${symbol}")
    list(LENGTH pieces len)
    if(len EQUAL 3)
      set(FortranCInterface_GLOBAL_${form}SYMBOL "${symbol}")
      list(GET pieces 0 FortranCInterface_GLOBAL_${form}PREFIX)
      list(GET pieces 1 name)
      list(GET pieces 2 FortranCInterface_GLOBAL_${form}SUFFIX)
      set(FortranCInterface_GLOBAL_${form}CASE "${_case_${name}}")
    endif()

    # Look for module symbols.
    string(REGEX REPLACE "${_module_${form}regex}"
                         "\\1;\\2;\\3;\\4;\\5" pieces "${symbol}")
    list(LENGTH pieces len)
    if(len EQUAL 5)
      set(FortranCInterface_MODULE_${form}SYMBOL "${symbol}")
      list(GET pieces 0 FortranCInterface_MODULE_${form}PREFIX)
      list(GET pieces 1 module)
      list(GET pieces 2 FortranCInterface_MODULE_${form}MIDDLE)
      list(GET pieces 3 name)
      list(GET pieces 4 FortranCInterface_MODULE_${form}SUFFIX)
      set(FortranCInterface_MODULE_${form}CASE "${_case_${name}}")
    endif()
  endforeach()
endforeach()

# Construct mangling macro definitions.
set(_name_LOWER "name")
set(_name_UPPER "NAME")
foreach(form "" "_")
  if(FortranCInterface_GLOBAL_${form}SYMBOL)
    if(FortranCInterface_GLOBAL_${form}PREFIX)
      set(_prefix "${FortranCInterface_GLOBAL_${form}PREFIX}##")
    else()
      set(_prefix "")
    endif()
    if(FortranCInterface_GLOBAL_${form}SUFFIX)
      set(_suffix "##${FortranCInterface_GLOBAL_${form}SUFFIX}")
    else()
      set(_suffix "")
    endif()
    set(_name "${_name_${FortranCInterface_GLOBAL_${form}CASE}}")
    set(FortranCInterface_GLOBAL${form}_MACRO
      "(name,NAME) ${_prefix}${_name}${_suffix}")
  endif()
  if(FortranCInterface_MODULE_${form}SYMBOL)
    if(FortranCInterface_MODULE_${form}PREFIX)
      set(_prefix "${FortranCInterface_MODULE_${form}PREFIX}##")
    else()
      set(_prefix "")
    endif()
    if(FortranCInterface_MODULE_${form}SUFFIX)
      set(_suffix "##${FortranCInterface_MODULE_${form}SUFFIX}")
    else()
      set(_suffix "")
    endif()
    set(_name "${_name_${FortranCInterface_MODULE_${form}CASE}}")
    set(_middle "##${FortranCInterface_MODULE_${form}MIDDLE}##")
    set(FortranCInterface_MODULE${form}_MACRO
      "(mod_name,name, mod_NAME,NAME) ${_prefix}mod_${_name}${_middle}${_name}${_suffix}")
  endif()
endforeach()

# Summarize what is available.
foreach(scope GLOBAL MODULE)
  if(FortranCInterface_${scope}_SYMBOL AND
      FortranCInterface_${scope}__SYMBOL)
    set(FortranCInterface_${scope}_FOUND 1)
  else()
    set(FortranCInterface_${scope}_FOUND 0)
  endif()
endforeach()

# Record the detection results.
configure_file(${FortranCInterface_SOURCE_DIR}/Output.cmake.in
               ${FortranCInterface_BINARY_DIR}/Output.cmake @ONLY)

# Report the results.
if(FortranCInterface_GLOBAL_FOUND)
  if(FortranCInterface_MODULE_FOUND)
    set(_result "Found GLOBAL and MODULE mangling")
  else()
    set(_result "Found GLOBAL but not MODULE mangling")
  endif()
  set(_result_type CHECK_PASS)
elseif(NOT _result)
  set(_result "Failed to recognize symbols")
  set(_result_type CHECK_FAIL)
endif()
message(${_result_type} "${_result}")