Rewrite FortranCInterface module

This is a new FortranCInterface.cmake module to replace the previous
prototype.  All module support files lie in a FortranCInterface
directory next to it.

This module uses a new approach to detect Fortran symbol mangling.  We
build a single test project which defines symbols in a Fortran library
(one per object-file) and calls them from a Fortran executable.  The
executable links to a C library which defines symbols encoding all known
manglings (one per object-file).  The C library falls back to the
Fortran library for symbols it cannot provide.  Therefore the executable
will always link, but prefers the C-implemented symbols when they match.
These symbols store string literals of the form INFO:symbol[<name>] so
we can parse them out of the executable.

This module also provides a simpler interface.  It always detects the
mangling as soon as it is included.  A single macro is provided to
generate mangling macros and optionally pre-mangled symbols.

14 files changed, 471 insertions, 223 deletions

diff --git a/Modules/FortranCInterface.cmake b/Modules/FortranCInterface.cmake
index 6551658..580f84e 100644
--- a/Modules/FortranCInterface.cmake
+++ b/Modules/FortranCInterface.cmake
@@ -1,231 +1,334 @@
-# FortranCInterface.cmake
+# - Fortran/C Interface Detection
+# This module automatically detects the API by which C and Fortran
+# languages interact.  Variables indicate if the mangling is found:
+#   FortranCInterface_GLOBAL_FOUND = Global subroutines and functions
+#   FortranCInterface_MODULE_FOUND = Module subroutines and functions
+#                                    (declared by "MODULE PROCEDURE")
+# A function is provided to generate a C header file containing macros
+# to mangle symbol names:
+#   FortranCInterface_HEADER(<file>
+#                            [MACRO_NAMESPACE <macro-ns>]
+#                            [SYMBOL_NAMESPACE <ns>]
+#                            [SYMBOLS [<module>:]<function> ...])
+# It generates in <file> definitions of the following macros:
+#   #define FortranCInterface_GLOBAL (name,NAME) ...
+#   #define FortranCInterface_GLOBAL_(name,NAME) ...
+#   #define FortranCInterface_MODULE (mod,name, MOD,NAME) ...
+#   #define FortranCInterface_MODULE_(mod,name, MOD,NAME) ...
+# These macros mangle four categories of Fortran symbols,
+# respectively:
+#   - Global symbols without '_': call mysub()
+#   - Global symbols with '_'   : call my_sub()
+#   - Module symbols without '_': use mymod; call mysub()
+#   - Module symbols with '_'   : use mymod; call my_sub()
+# If mangling for a category is not known, its macro is left undefined.
+# All macros require raw names in both lower case and upper case.
+# The MACRO_NAMESPACE option replaces the default "FortranCInterface_"
+# prefix with a given namespace "<macro-ns>".
 #
-# This file defines the function create_fortran_c_interface.
-# this function is used to create a configured header file 
-# that contains a mapping from C to a Fortran function using
-# the correct name mangling scheme as defined by the current 
-# fortran compiler.  
+# The SYMBOLS option lists symbols to mangle automatically with C
+# preprocessor definitions:
+#   <function>          ==> #define <ns><function> ...
+#   <module>:<function> ==> #define <ns><module>_<function> ...
+# If the mangling for some symbol is not known then no preprocessor
+# definition is created, and a warning is displayed.
+# The SYMBOL_NAMESPACE option prefixes all preprocessor definitions
+# generated by the SYMBOLS option with a given namespace "<ns>".
 #
-# The function tages a list of functions and the name of 
-# a header file to configure.  
+# Example usage:
+#   include(FortranCInterface)
+#   FortranCInterface_HEADER(FC.h MACRO_NAMESPACE "FC_")
+# This creates a "FC.h" header that defines mangling macros
+# FC_GLOBAL(), FC_GLOBAL_(), FC_MODULE(), and FC_MODULE_().
 #
-# This file also defines some helper functions that are used
-# to detect the fortran name mangling scheme used by the 
-# current Fortran compiler.
-#  test_fortran_mangling - test a single fortran mangling 
-#  discover_fortran_mangling - loop over all combos of fortran
-#   name mangling and call test_fortran_mangling until one of them
-#   works.
-#  discover_fortran_module_mangling - try different types of 
-#  fortran modle name mangling to find one that works
+# Example usage:
+#   include(FortranCInterface)
+#   FortranCInterface_HEADER(FCMangle.h
+#                            MACRO_NAMESPACE "FC_"
+#                            SYMBOL_NAMESPACE "FC_"
+#                            SYMBOLS mysub mymod:my_sub)
+# This creates a "FC.h" header that defines the same FC_*() mangling
+# macros as the previous example plus preprocessor symbols FC_mysub
+# and FC_mymod_my_sub.
 #
-#
-#
-# this function tests a single fortran mangling.  
-# CODE - test code to try should define a subroutine called "sub"
-# PREFIX - string to put in front of sub
-# POSTFIX - string to put after sub
-# ISUPPER - if TRUE then sub will be called as SUB
-# DOC - string used in status checking Fortran ${DOC} linkage
-# SUB - the name of the SUB to call
-# RESULT place to store result TRUE if this linkage works, FALSE
-#        if not.
-#
-function(test_fortran_mangling CODE PREFIX ISUPPER POSTFIX DOC SUB RESULT)
-  if(ISUPPER)
-    string(TOUPPER "${SUB}" sub)
-  else(ISUPPER) 
-    string(TOLOWER "${SUB}" sub)
-  endif(ISUPPER)
-  set(FUNCTION "${PREFIX}${sub}${POSTFIX}")
-  # create a fortran file with sub called sub
-  # 
-  set(TMP_DIR
-    "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckFortranLink")
-  file(REMOVE_RECURSE "${TMP_DIR}")
-  file(WRITE "${TMP_DIR}/test.f" "${CODE}"    )
-  message(STATUS "checking Fortran ${DOC} linkage: ${FUNCTION}")
-  file(WRITE "${TMP_DIR}/ctof.c"
-    "
-      extern ${FUNCTION}();
-      int main() { ${FUNCTION}(); return 0;}
-    "
-    )
-  file(WRITE "${TMP_DIR}/CMakeLists.txt"
-    "
-     project(testf C Fortran)
-     add_library(flib test.f)
-     add_executable(ctof ctof.c)
-     target_link_libraries(ctof flib)
-    "
+# FortranCInterface is aware of possible GLOBAL and MODULE manglings
+# for many Fortran compilers, but it also provides an interface to
+# specify new possible manglings.  Set the variables
+#   FortranCInterface_GLOBAL_SYMBOLS
+#   FortranCInterface_MODULE_SYMBOLS
+# before including FortranCInterface to specify manglings of the
+# symbols "MySub", "My_Sub", "MyModule:MySub", and "My_Module:My_Sub".
+# For example, the code:
+#   set(FortranCInterface_GLOBAL_SYMBOLS mysub_ my_sub__ MYSUB_)
+#     #                                  ^^^^^  ^^^^^^   ^^^^^
+#   set(FortranCInterface_MODULE_SYMBOLS
+#       __mymodule_MOD_mysub __my_module_MOD_my_sub)
+#     #   ^^^^^^^^     ^^^^^   ^^^^^^^^^     ^^^^^^
+#   include(FortranCInterface)
+# tells FortranCInterface to try given GLOBAL and MODULE manglings.
+# (The carets point at raw symbol names for clarity in this example
+# but are not needed.)
+
+#-----------------------------------------------------------------------------
+# Execute at most once in a project.
+if(FortranCInterface_SOURCE_DIR)
+  return()
+endif()
+
+#-----------------------------------------------------------------------------
+# Set up an interface detection project.
+set(FortranCInterface_SOURCE_DIR ${CMAKE_ROOT}/Modules/FortranCInterface)
+set(FortranCInterface_BINARY_DIR ${CMAKE_BINARY_DIR}/CMakeFiles/FortranCInterface)
+configure_file(${FortranCInterface_SOURCE_DIR}/Input.cmake.in
+               ${FortranCInterface_BINARY_DIR}/Input.cmake @ONLY)
+
+# Detect the Fortran/C interface on the first run or when the
+# configuration changes.
+if(${FortranCInterface_BINARY_DIR}/Input.cmake
+    IS_NEWER_THAN ${FortranCInterface_BINARY_DIR}/Output.cmake
+    OR ${FortranCInterface_SOURCE_DIR}/Output.cmake.in
+    IS_NEWER_THAN ${FortranCInterface_BINARY_DIR}/Output.cmake
+    OR ${FortranCInterface_SOURCE_DIR}/CMakeLists.txt
+    IS_NEWER_THAN ${FortranCInterface_BINARY_DIR}/Output.cmake
+    OR ${CMAKE_CURRENT_LIST_FILE}
+    IS_NEWER_THAN ${FortranCInterface_BINARY_DIR}/Output.cmake
     )
-  set(FORTRAN_NAME_MANGLE_TEST FALSE)
-  try_compile(FORTRAN_NAME_MANGLE_TEST "${TMP_DIR}" "${TMP_DIR}"
-    testf
-    OUTPUT_VARIABLE output)
-  if(FORTRAN_NAME_MANGLE_TEST)
-    set(${RESULT} TRUE PARENT_SCOPE)
+  message(STATUS "Detecting Fortran/C Interface")
+  set(_result)
+
+  # Build a sample project which reports symbols.
+  try_compile(FortranCInterface_COMPILED
+    ${FortranCInterface_BINARY_DIR}
+    ${FortranCInterface_SOURCE_DIR}
+    FortranCInterface
+    OUTPUT_VARIABLE FortranCInterface_OUTPUT)
+  set(FortranCInterface_COMPILED ${FortranCInterface_COMPILED})
+  unset(FortranCInterface_COMPILED CACHE)
+
+  # Locate the sample project executable.
+  if(FortranCInterface_COMPILED)
+    find_program(FortranCInterface_EXE
+      NAMES FortranCInterface
+      PATHS ${FortranCInterface_BINARY_DIR} ${FortranCInterface_BINARY_DIR}/Debug
+      NO_DEFAULT_PATH
+      )
+    set(FortranCInterface_EXE ${FortranCInterface_EXE})
+    unset(FortranCInterface_EXE CACHE)
   else()
-    set(${RESULT} FALSE PARENT_SCOPE)
+    set(_result "Failed to compile")
+    set(FortranCInterface_EXE)
+    file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
+      "Fortran/C interface test project failed with the following output:\n"
+      "${FortranCInterface_OUTPUT}\n")
   endif()
-endfunction(test_fortran_mangling)
-
-# this function discovers the name mangling scheme used
-# for functions in a fortran module.  
-function(discover_fortran_module_mangling prefix suffix found)
-  set(CODE 
-    "
-      module test_interface
-      interface dummy
-         module procedure sub
-      end interface
-      contains
-        subroutine sub
-        end subroutine
-      end module test_interface
-    ")
-  set(worked FALSE)
-  foreach(interface 
-      "test_interface$" 
-      "TEST_INTERFACE_mp_" 
-      "_test_interface__" 
-      "__test_interface__" 
-      "__test_interface_NMOD_" 
-      "__test_interface_MOD_")
-    test_fortran_mangling("${CODE}" "${interface}"
-      ${FORTRAN_C_MANGLING_UPPERCASE} "" "module" "sub" worked)
-    if(worked)
-      # if this is the upper case module match then
-      # lower case it for the extraction of pre and post strings
-      if("${interface}" MATCHES "TEST_INTERFACE")
-        string(TOLOWER "${interface}" interface)
+
+  # Load symbols from INFO:symbol[] strings in the executable.
+  set(FortranCInterface_SYMBOLS)
+  if(FortranCInterface_EXE)
+    file(STRINGS "${FortranCInterface_EXE}" _info_strings
+      LIMIT_COUNT 8 REGEX "INFO:[^[]*\\[")
+    foreach(info ${_info_strings})
+      if("${info}" MATCHES ".*INFO:symbol\\[([^]]*)\\].*")
+        string(REGEX REPLACE ".*INFO:symbol\\[([^]]*)\\].*" "\\1" symbol "${info}")
+        list(APPEND FortranCInterface_SYMBOLS ${symbol})
+      endif()
+    endforeach()
+  elseif(NOT _result)
+    set(_result "Failed to load sample executable")
+  endif()
+
+  set(_case_mysub "LOWER")
+  set(_case_my_sub "LOWER")
+  set(_case_MYSUB "UPPER")
+  set(_case_MY_SUB "UPPER")
+  set(_global_regex  "^(_*)(mysub|MYSUB)([_$]*)$")
+  set(_global__regex "^(_*)(my_sub|MY_SUB)([_$]*)$")
+  set(_module_regex  "^(_*)(mymodule|MYMODULE)([A-Za-z_$]*)(mysub|MYSUB)([_$]*)$")
+  set(_module__regex "^(_*)(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()
-      string(REGEX REPLACE "(.*)test_interface(.*)" "\\1" pre "${interface}")
-      string(REGEX REPLACE "(.*)test_interface(.*)" "\\2" post "${interface}")
-      set(${prefix} "${pre}" PARENT_SCOPE)
-      set(${suffix} "${post}" PARENT_SCOPE)
-      set(${found} TRUE PARENT_SCOPE)
-      return()
-    endif(worked)
-  endforeach(interface)
-  if(NOT worked)
-    message(STATUS "Failed to find C binding to Fortran module functions.")
-    set(${prefix} "BROKEN_C_FORTRAN_MODULE_BINDING" PARENT_SCOPE)
-    set(${suffix} "BROKEN_C_FORTRAN_MODULE_BINDING" PARENT_SCOPE)
-    set(${found} FALSE PARENT_SCOPE)
-  endif(NOT worked)
-endfunction(discover_fortran_module_mangling)
-
-
-function(discover_fortran_mangling prefix isupper suffix extra_under_score
-    found )
-  set(CODE 
-    "
-      subroutine sub
-      end subroutine sub
-    ")
-  foreach(post "_" "")
-    foreach(isup FALSE TRUE)
-      foreach(pre "" "_" "__")
-        set(worked FALSE)
-        test_fortran_mangling("${CODE}" "${pre}" ${isup}
-          "${post}" "function" sub worked )
-        if(worked)
-          message(STATUS "found Fortran function linkage")
-          set(${isupper} "${isup}" PARENT_SCOPE)
-          set(${prefix} "${pre}" PARENT_SCOPE)
-          set(${suffix} "${post}" PARENT_SCOPE)
-          set(${found} TRUE PARENT_SCOPE)
-          set(CODE 
-            "
-      subroutine my_sub
-      end subroutine my_sub
-    ")
-          set(worked FALSE)
-          test_fortran_mangling("${CODE}" "${pre}" ${isup}
-            "${post}" "function with _ " my_sub worked )
-          if(worked)
-            set(${extra_under_score} FALSE PARENT_SCOPE)
-          else(worked)
-            test_fortran_mangling("${CODE}" "${pre}" ${isup}
-              "${post}_" "function with _ " my_sub worked )
-            if(worked)
-              set(${extra_under_score} TRUE PARENT_SCOPE)
-            endif(worked)
-          endif(worked)
-        return()
-        endif()
-      endforeach()
     endforeach()
   endforeach()
-  set(${found} FALSE PARENT_SCOPE)
-endfunction(discover_fortran_mangling)
-
-function(create_fortran_c_interface NAMESPACE FUNCTIONS HEADER)
-  if(NOT FORTRAN_C_MANGLING_FOUND)
-    # find regular fortran function mangling
-    discover_fortran_mangling(prefix isupper suffix extra_under found)
-    if(NOT found)
-      message(SEND_ERROR "Could not find fortran c name mangling.")
-      return()
-    endif(NOT found)
-    # find fortran module function mangling
-    set(FORTRAN_C_PREFIX "${prefix}" CACHE INTERNAL
-      "PREFIX for Fortran to c name mangling")
-    set(FORTRAN_C_SUFFIX "${suffix}" CACHE INTERNAL
-      "SUFFIX for Fortran to c name mangling")
-    set(FORTRAN_C_MANGLING_UPPERCASE ${isupper} CACHE INTERNAL 
-      "Was fortran to c mangling found" )
-    set(FORTRAN_C_MANGLING_EXTRA_UNDERSCORE ${extra_under} CACHE INTERNAL 
-      "If a function has a _ in the name does the compiler append an extra _" )
-    set(FORTRAN_C_MANGLING_FOUND TRUE CACHE INTERNAL 
-      "Was fortran to c mangling found" )
-    set(prefix )
-    set(suffix )
-    set(found FALSE)
-    # only try this if the compiler is F90 compatible
-    if(CMAKE_Fortran_COMPILER_SUPPORTS_F90)
-      discover_fortran_module_mangling(prefix suffix found)
-    endif(CMAKE_Fortran_COMPILER_SUPPORTS_F90)
-    if(found)
-      message(STATUS "found Fortran module linkage")
-    else(found)
-      message(STATUS "Failed to find Fortran module linkage")
-    endif(found)
-    set(FORTRAN_C_MODULE_PREFIX "${prefix}" CACHE INTERNAL
-      "PREFIX for Fortran to c name mangling")
-    set(FORTRAN_C_MODULE_SUFFIX "${suffix}" CACHE INTERNAL
-      "SUFFIX for Fortran to c name mangling")
-    set(FORTRAN_C_MODULE_MANGLING_FOUND ${found} CACHE INTERNAL
-      "Was for Fortran to c name mangling found for modules")
-  endif(NOT FORTRAN_C_MANGLING_FOUND)
-  foreach(f ${${FUNCTIONS}})
-    if(FORTRAN_C_MANGLING_UPPERCASE)
-      string(TOUPPER "${f}" fcase)
+
+  # Construct mangling macro definitions.
+  set(_name_LOWER "name")
+  set(_name_UPPER "NAME")
+  foreach(form "" "_")
+    if(FortranCInterface_GLOBAL_${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()
-      string(TOLOWER "${f}" fcase)
+      set(FortranCInterface_${scope}_FOUND 0)
     endif()
-    if("${f}" MATCHES ":")
-      string(REGEX REPLACE "(.*):(.*)" "\\1" module "${f}")
-      string(REGEX REPLACE "(.*):(.*)" "\\2" function "${f}")
-      string(REGEX REPLACE "(.*):(.*)" "\\1" module_case "${fcase}")
-      string(REGEX REPLACE "(.*):(.*)" "\\2" function_case "${fcase}")
+  endforeach()
+
+  # Record the detection results.
+  configure_file(${FortranCInterface_SOURCE_DIR}/Output.cmake.in
+                 ${FortranCInterface_BINARY_DIR}/Output.cmake @ONLY)
+  file(APPEND ${FortranCInterface_BINARY_DIR}/Output.cmake "\n")
+
+  # Report the results.
+  if(FortranCInterface_GLOBAL_FOUND)
+    if(FortranCInterface_MODULE_FOUND)
+      set(_result "Found GLOBAL and MODULE mangling")
+    else(FortranCInterface_MODULE_FOUND)
+      set(_result "Found GLOBAL but not MODULE mangling")
+    endif()
+  elseif(NOT _result)
+    set(_result "Failed to recognize symbols")
+  endif()
+  message(STATUS "Detecting Fortran/C Interface - ${_result}")
+endif()
+
+# Load the detection results.
+include(${FortranCInterface_BINARY_DIR}/Output.cmake)
+
+#-----------------------------------------------------------------------------
+function(FortranCInterface_HEADER file)
+  # Parse arguments.
+  if(IS_ABSOLUTE "${file}")
+    set(FILE "${file}")
+  else()
+    set(FILE "${CMAKE_CURRENT_BINARY_DIR}/${file}")
+  endif()
+  set(MACRO_NAMESPACE "FortranCInterface_")
+  set(SYMBOL_NAMESPACE)
+  set(SYMBOLS)
+  set(doing)
+  foreach(arg ${ARGN})
+    if("x${arg}" MATCHES "^x(SYMBOLS|SYMBOL_NAMESPACE|MACRO_NAMESPACE)$")
+      set(doing "${arg}")
+    elseif("x${doing}" MATCHES "^x(SYMBOLS)$")
+      list(APPEND "${doing}" "${arg}")
+    elseif("x${doing}" MATCHES "^x(SYMBOL_NAMESPACE|MACRO_NAMESPACE)$")
+      set("${doing}" "${arg}")
+      set(doing)
+    else()
+      message(AUTHOR_WARNING "Unknown argument: \"${arg}\"")
+    endif()
+  endforeach()
+
+  # Generate macro definitions.
+  set(HEADER_CONTENT)
+  set(_desc_GLOBAL  "/* Mangling for Fortran global symbols without underscores. */")
+  set(_desc_GLOBAL_ "/* Mangling for Fortran global symbols with underscores. */")
+  set(_desc_MODULE  "/* Mangling for Fortran module symbols without underscores. */")
+  set(_desc_MODULE_ "/* Mangling for Fortran module symbols with underscores. */")
+  foreach(macro GLOBAL GLOBAL_ MODULE MODULE_)
+    if(FortranCInterface_${macro}_MACRO)
       set(HEADER_CONTENT "${HEADER_CONTENT}
-#define ${NAMESPACE}${module}_${function} ${FORTRAN_C_MODULE_PREFIX}${module_case}${FORTRAN_C_MODULE_SUFFIX}${function_case}
+${_desc_${macro}}
+#define ${MACRO_NAMESPACE}${macro}${FortranCInterface_${macro}_MACRO}
 ")
-    else("${f}" MATCHES ":")
-      set(function "${FORTRAN_C_PREFIX}${fcase}${FORTRAN_C_SUFFIX}")
-      if("${f}" MATCHES "_" AND FORTRAN_C_MANGLING_EXTRA_UNDERSCORE)
-        set(function "${function}_")
-      endif("${f}" MATCHES "_" AND FORTRAN_C_MANGLING_EXTRA_UNDERSCORE)
-      set(HEADER_CONTENT "${HEADER_CONTENT}
-#define ${NAMESPACE}${f} ${function}
+    endif()
+  endforeach()
+
+  # Generate symbol mangling definitions.
+  if(SYMBOLS)
+    set(HEADER_CONTENT "${HEADER_CONTENT}
+/*--------------------------------------------------------------------------*/
+/* Mangle some symbols automatically.                                       */
 ")
-    endif("${f}" MATCHES ":")
+  endif()
+  foreach(f ${SYMBOLS})
+    if("${f}" MATCHES ":")
+      # Module symbol name.  Parse "<module>:<function>" syntax.
+      string(REPLACE ":" ";" pieces "${f}")
+      list(GET pieces 0 module)
+      list(GET pieces 1 function)
+      string(TOUPPER "${module}" m_upper)
+      string(TOLOWER "${module}" m_lower)
+      string(TOUPPER "${function}" f_upper)
+      string(TOLOWER "${function}" f_lower)
+      if("${function}" MATCHES "_")
+        set(form "_")
+      else()
+        set(form "")
+      endif()
+      if(FortranCInterface_MODULE${form}_MACRO)
+        set(HEADER_CONTENT "${HEADER_CONTENT}#define ${SYMBOL_NAMESPACE}${module}_${function} ${MACRO_NAMESPACE}MODULE${form}(${m_lower},${f_lower}, ${m_upper},${f_upper})\n")
+      else()
+        message(AUTHOR_WARNING "No FortranCInterface mangling known for ${f}")
+      endif()
+    else()
+      # Global symbol name.
+      if("${f}" MATCHES "_")
+        set(form "_")
+      else()
+        set(form "")
+      endif()
+      string(TOUPPER "${f}" f_upper)
+      string(TOLOWER "${f}" f_lower)
+      if(FortranCInterface_GLOBAL${form}_MACRO)
+        set(HEADER_CONTENT "${HEADER_CONTENT}#define ${SYMBOL_NAMESPACE}${f} ${MACRO_NAMESPACE}GLOBAL${form}(${f_lower}, ${f_upper})\n")
+      else()
+        message(AUTHOR_WARNING "No FortranCInterface mangling known for ${f}")
+      endif()
+    endif()
   endforeach(f)
-  configure_file(
-    "${CMAKE_ROOT}/Modules/FortranCInterface.h.in"
-    ${HEADER} @ONLY)
-  message(STATUS "created ${HEADER}")
-endfunction()
 
+  # Store the content.
+  configure_file(${FortranCInterface_SOURCE_DIR}/Macro.h.in ${FILE} @ONLY)
+endfunction()
diff --git a/Modules/FortranCInterface.h.in b/Modules/FortranCInterface.h.in
deleted file mode 100644
index 0250175..0000000
--- a/Modules/FortranCInterface.h.in
+++ /dev/null
@@ -1,9 +0,0 @@
-/* This file is automatically generated by CMake, DO NOT EDIT.
-   It contains a mapping from Fortran functions so they can 
-   be called from C or C++.   */
-
-
-@HEADER_CONTENT@
-
-
-
diff --git a/Modules/FortranCInterface/CMakeLists.txt b/Modules/FortranCInterface/CMakeLists.txt
new file mode 100644
index 0000000..4bc7a10
--- /dev/null
+++ b/Modules/FortranCInterface/CMakeLists.txt
@@ -0,0 +1,74 @@
+cmake_minimum_required(VERSION 2.6.3)
+project(FortranCInterface C Fortran)
+include(${FortranCInterface_BINARY_DIR}/Input.cmake OPTIONAL)
+
+# Check if the C compiler supports '$' in identifiers.
+include(CheckCSourceCompiles)
+check_c_source_compiles("
+extern int dollar$(void);
+int main() { return 0; }
+" C_SUPPORTS_DOLLAR)
+
+# List manglings of global symbol names to try.
+set(global_symbols
+  my_sub_   # GNU, Intel, HP, SunPro, MIPSpro
+  my_sub    # VisualAge
+  mysub_    # GNU, Intel, HP, SunPro, MIPSpro
+  mysub     # VisualAge
+  ${FortranCInterface_GLOBAL_SYMBOLS}
+  )
+list(REMOVE_DUPLICATES global_symbols)
+
+# List manglings of module symbol names to try.
+set(module_symbols
+  __my_module_MOD_my_sub  # GNU
+  __my_module_NMOD_my_sub # VisualAge
+  __mymodule_MOD_mysub    # GNU
+  __mymodule_NMOD_mysub   # VisualAge
+  my_module$my_sub        # HP
+  my_module_mp_my_sub_    # Intel
+  mymodule$mysub          # HP
+  mymodule_mp_mysub_      # Intel
+  ${FortranCInterface_MODULE_SYMBOLS}
+  )
+list(REMOVE_DUPLICATES module_symbols)
+
+# Note that some compiler manglings cannot be invoked from C:
+#   MIPSpro uses "MY_SUB.in.MY_MODULE"
+#   SunPro uses "my_module.my_sub_"
+
+# Add module symbols only with Fortran90.
+if(CMAKE_Fortran_COMPILER_SUPPORTS_F90)
+  set(myfort_modules mymodule.f90 my_module.f90)
+  set(call_mod call_mod.f90)
+  set_property(SOURCE main.F PROPERTY COMPILE_DEFINITIONS CALL_MOD)
+else()
+  set(module_symbols)
+endif()
+
+# Generate C symbol sources.
+foreach(symbol IN LISTS global_symbols module_symbols)
+  # Skip symbols with '$' if C cannot handle them.
+  if(C_SUPPORTS_DOLLAR OR NOT "${symbol}" MATCHES "\\$")
+    if("${symbol}" MATCHES "SUB")
+      set(upper "-UPPER")
+    else()
+      set(upper)
+    endif()
+    string(REPLACE "$" "S" name "${symbol}")
+    set(source ${CMAKE_CURRENT_BINARY_DIR}/symbols/${name}${upper}.c)
+    configure_file(${CMAKE_CURRENT_SOURCE_DIR}/symbol.c.in ${source} @ONLY)
+    list(APPEND symbol_sources ${source})
+  endif()
+endforeach()
+
+# Provide symbols through Fortran.
+add_library(myfort STATIC mysub.f my_sub.f ${myfort_modules})
+
+# Provide symbols through C but fall back to Fortran.
+add_library(symbols STATIC ${symbol_sources})
+target_link_libraries(symbols myfort)
+
+# Require symbols through Fortran.
+add_executable(FortranCInterface main.F call_sub.f ${call_mod})
+target_link_libraries(FortranCInterface symbols)
diff --git a/Modules/FortranCInterface/Input.cmake.in b/Modules/FortranCInterface/Input.cmake.in
new file mode 100644
index 0000000..f261e3b
--- /dev/null
+++ b/Modules/FortranCInterface/Input.cmake.in
@@ -0,0 +1,3 @@
+set(CMAKE_Fortran_COMPILER_ID "@CMAKE_Fortran_COMPILER_ID@")
+set(FortranCInterface_GLOBAL_SYMBOLS "@FortranCInterface_GLOBAL_SYMBOLS@")
+set(FortranCInterface_MODULE_SYMBOLS "@FortranCInterface_MODULE_SYMBOLS@")
diff --git a/Modules/FortranCInterface/Macro.h.in b/Modules/FortranCInterface/Macro.h.in
new file mode 100644
index 0000000..d015a62
--- /dev/null
+++ b/Modules/FortranCInterface/Macro.h.in
@@ -0,0 +1,4 @@
+#ifndef @MACRO_NAMESPACE@HEADER_INCLUDED
+#define @MACRO_NAMESPACE@HEADER_INCLUDED
+@HEADER_CONTENT@
+#endif
diff --git a/Modules/FortranCInterface/Output.cmake.in b/Modules/FortranCInterface/Output.cmake.in
new file mode 100644
index 0000000..bce410e
--- /dev/null
+++ b/Modules/FortranCInterface/Output.cmake.in
@@ -0,0 +1,33 @@
+# Global symbol without underscore.
+set(FortranCInterface_GLOBAL_SYMBOL  "@FortranCInterface_GLOBAL_SYMBOL@")
+set(FortranCInterface_GLOBAL_PREFIX  "@FortranCInterface_GLOBAL_PREFIX@")
+set(FortranCInterface_GLOBAL_SUFFIX  "@FortranCInterface_GLOBAL_SUFFIX@")
+set(FortranCInterface_GLOBAL_CASE    "@FortranCInterface_GLOBAL_CASE@")
+set(FortranCInterface_GLOBAL_MACRO   "@FortranCInterface_GLOBAL_MACRO@")
+
+# Global symbol with underscore.
+set(FortranCInterface_GLOBAL__SYMBOL "@FortranCInterface_GLOBAL__SYMBOL@")
+set(FortranCInterface_GLOBAL__PREFIX "@FortranCInterface_GLOBAL__PREFIX@")
+set(FortranCInterface_GLOBAL__SUFFIX "@FortranCInterface_GLOBAL__SUFFIX@")
+set(FortranCInterface_GLOBAL__CASE   "@FortranCInterface_GLOBAL__CASE@")
+set(FortranCInterface_GLOBAL__MACRO  "@FortranCInterface_GLOBAL__MACRO@")
+
+# Module symbol without underscore.
+set(FortranCInterface_MODULE_SYMBOL  "@FortranCInterface_MODULE_SYMBOL@")
+set(FortranCInterface_MODULE_PREFIX  "@FortranCInterface_MODULE_PREFIX@")
+set(FortranCInterface_MODULE_MIDDLE  "@FortranCInterface_MODULE_MIDDLE@")
+set(FortranCInterface_MODULE_SUFFIX  "@FortranCInterface_MODULE_SUFFIX@")
+set(FortranCInterface_MODULE_CASE    "@FortranCInterface_MODULE_CASE@")
+set(FortranCInterface_MODULE_MACRO   "@FortranCInterface_MODULE_MACRO@")
+
+# Module symbol with underscore.
+set(FortranCInterface_MODULE__SYMBOL "@FortranCInterface_MODULE__SYMBOL@")
+set(FortranCInterface_MODULE__PREFIX "@FortranCInterface_MODULE__PREFIX@")
+set(FortranCInterface_MODULE__MIDDLE "@FortranCInterface_MODULE__MIDDLE@")
+set(FortranCInterface_MODULE__SUFFIX "@FortranCInterface_MODULE__SUFFIX@")
+set(FortranCInterface_MODULE__CASE   "@FortranCInterface_MODULE__CASE@")
+set(FortranCInterface_MODULE__MACRO  "@FortranCInterface_MODULE__MACRO@")
+
+# Summarize what was found.
+set(FortranCInterface_GLOBAL_FOUND @FortranCInterface_GLOBAL_FOUND@)
+set(FortranCInterface_MODULE_FOUND @FortranCInterface_MODULE_FOUND@)
diff --git a/Modules/FortranCInterface/call_mod.f90 b/Modules/FortranCInterface/call_mod.f90
new file mode 100644
index 0000000..9b6af64
--- /dev/null
+++ b/Modules/FortranCInterface/call_mod.f90
@@ -0,0 +1,6 @@
+subroutine call_mod
+  use mymodule
+  use my_module
+  call mysub()
+  call my_sub()
+end subroutine call_mod
diff --git a/Modules/FortranCInterface/call_sub.f b/Modules/FortranCInterface/call_sub.f
new file mode 100644
index 0000000..ce3d50b
--- /dev/null
+++ b/Modules/FortranCInterface/call_sub.f
@@ -0,0 +1,4 @@
+        subroutine call_sub
+          call mysub()
+          call my_sub()
+        end
diff --git a/Modules/FortranCInterface/main.F b/Modules/FortranCInterface/main.F
new file mode 100644
index 0000000..84991b0
--- /dev/null
+++ b/Modules/FortranCInterface/main.F
@@ -0,0 +1,6 @@
+        program main
+          call call_sub()
+#ifdef CALL_MOD
+          call call_mod()
+#endif
+        end
diff --git a/Modules/FortranCInterface/my_module.f90 b/Modules/FortranCInterface/my_module.f90
new file mode 100644
index 0000000..82713b4
--- /dev/null
+++ b/Modules/FortranCInterface/my_module.f90
@@ -0,0 +1,8 @@
+module my_module
+  interface my_interface
+     module procedure my_sub
+  end interface
+contains
+  subroutine my_sub
+  end subroutine my_sub
+end module my_module
diff --git a/Modules/FortranCInterface/my_sub.f b/Modules/FortranCInterface/my_sub.f
new file mode 100644
index 0000000..247ba06
--- /dev/null
+++ b/Modules/FortranCInterface/my_sub.f
@@ -0,0 +1,2 @@
+      subroutine my_sub
+      end
diff --git a/Modules/FortranCInterface/mymodule.f90 b/Modules/FortranCInterface/mymodule.f90
new file mode 100644
index 0000000..ef6281a
--- /dev/null
+++ b/Modules/FortranCInterface/mymodule.f90
@@ -0,0 +1,8 @@
+module mymodule
+  interface myinterface
+     module procedure mysub
+  end interface
+contains
+  subroutine mysub
+  end subroutine mysub
+end module mymodule
diff --git a/Modules/FortranCInterface/mysub.f b/Modules/FortranCInterface/mysub.f
new file mode 100644
index 0000000..1c27ff4
--- /dev/null
+++ b/Modules/FortranCInterface/mysub.f
@@ -0,0 +1,2 @@
+      subroutine mysub
+      end
diff --git a/Modules/FortranCInterface/symbol.c.in b/Modules/FortranCInterface/symbol.c.in
new file mode 100644
index 0000000..369fa45
--- /dev/null
+++ b/Modules/FortranCInterface/symbol.c.in
@@ -0,0 +1,4 @@
+const char* @symbol@(void)
+{
+  return "INFO:symbol[@symbol@]";
+}