CMake/Modules/FortranCInterface.cmake

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# - 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>".
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#
# 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>".
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#
# 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_().
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#
# 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.
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#
# Another function is provided to verify that the Fortran and C/C++
# compilers work together:
# FortranCInterface_VERIFY([CXX] [QUIET])
# It tests whether a simple test executable using Fortran and C (and
# C++ when the CXX option is given) compiles and links successfully.
# The result is stored in the cache entry FortranCInterface_VERIFIED_C
# (or FortranCInterface_VERIFIED_CXX if CXX is given) as a boolean.
# If the check fails and QUIET is not given the function terminates
# with a FATAL_ERROR message describing the problem. The purpose of
# this check is to stop a build early for incompatible compiler
# combinations.
#
# 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()
#-----------------------------------------------------------------------------
# Verify that C and Fortran are available.
foreach(lang C Fortran)
if(NOT CMAKE_${lang}_COMPILER_LOADED)
message(FATAL_ERROR
"FortranCInterface requires the ${lang} language to be enabled.")
endif()
endforeach()
#-----------------------------------------------------------------------------
set(FortranCInterface_SOURCE_DIR ${CMAKE_ROOT}/Modules/FortranCInterface)
# Create the interface detection project if it does not exist.
if(NOT FortranCInterface_BINARY_DIR)
set(FortranCInterface_BINARY_DIR ${CMAKE_BINARY_DIR}/CMakeFiles/FortranCInterface)
include(${FortranCInterface_SOURCE_DIR}/Detect.cmake)
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)
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set(HEADER_CONTENT "${HEADER_CONTENT}
${_desc_${macro}}
#define ${MACRO_NAMESPACE}${macro}${FortranCInterface_${macro}_MACRO}
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")
endif()
endforeach()
# Generate symbol mangling definitions.
if(SYMBOLS)
set(HEADER_CONTENT "${HEADER_CONTENT}
/*--------------------------------------------------------------------------*/
/* Mangle some symbols automatically. */
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")
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 ${f}")
endif()
endif()
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endforeach(f)
# Store the content.
configure_file(${FortranCInterface_SOURCE_DIR}/Macro.h.in ${FILE} @ONLY)
endfunction()
function(FortranCInterface_VERIFY)
# Check arguments.
set(lang C)
set(quiet 0)
set(verify_cxx 0)
foreach(arg ${ARGN})
if("${arg}" STREQUAL "QUIET")
set(quiet 1)
elseif("${arg}" STREQUAL "CXX")
set(lang CXX)
set(verify_cxx 1)
else()
message(FATAL_ERROR
"FortranCInterface_VERIFY - called with unknown argument:\n ${arg}")
endif()
endforeach()
if(NOT CMAKE_${lang}_COMPILER_LOADED)
message(FATAL_ERROR
"FortranCInterface_VERIFY(${lang}) requires ${lang} to be enabled.")
endif()
# Build the verification project if not yet built.
if(NOT DEFINED FortranCInterface_VERIFIED_${lang})
set(_desc "Verifying Fortran/${lang} Compiler Compatibility")
message(STATUS "${_desc}")
# Build a sample project which reports symbols.
try_compile(FortranCInterface_VERIFY_${lang}_COMPILED
${FortranCInterface_BINARY_DIR}/Verify${lang}
${FortranCInterface_SOURCE_DIR}/Verify
VerifyFortranC
CMAKE_FLAGS -DVERIFY_CXX=${verify_cxx}
-DCMAKE_VERBOSE_MAKEFILE=ON
OUTPUT_VARIABLE _output)
file(WRITE "${FortranCInterface_BINARY_DIR}/Verify${lang}/output.txt" "${_output}")
# Report results.
if(FortranCInterface_VERIFY_${lang}_COMPILED)
message(STATUS "${_desc} - Success")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
"${_desc} passed with the following output:\n${_output}\n\n")
set(FortranCInterface_VERIFIED_${lang} 1 CACHE INTERNAL "Fortran/${lang} compatibility")
else()
message(STATUS "${_desc} - Failed")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
"${_desc} failed with the following output:\n${_output}\n\n")
set(FortranCInterface_VERIFIED_${lang} 0 CACHE INTERNAL "Fortran/${lang} compatibility")
endif()
unset(FortranCInterface_VERIFY_${lang}_COMPILED CACHE)
endif()
# Error if compilers are incompatible.
if(NOT FortranCInterface_VERIFIED_${lang} AND NOT quiet)
file(READ "${FortranCInterface_BINARY_DIR}/Verify${lang}/output.txt" _output)
string(REGEX REPLACE "\n" "\n " _output "${_output}")
message(FATAL_ERROR
"The Fortran compiler:\n ${CMAKE_Fortran_COMPILER}\n"
"and the ${lang} compiler:\n ${CMAKE_${lang}_COMPILER}\n"
"failed to compile a simple test project using both languages. "
"The output was:\n ${_output}")
endif()
endfunction()