# tools/pybind11Tools.cmake -- Build system for the pybind11 modules # # Copyright (c) 2015 Wenzel Jakob # # All rights reserved. Use of this source code is governed by a # BSD-style license that can be found in the LICENSE file. # Add a CMake parameter for choosing a desired Python version if(NOT PYBIND11_PYTHON_VERSION) set(PYBIND11_PYTHON_VERSION "" CACHE STRING "Python version to use for compiling modules") endif() # A user can set versions manually too set(Python_ADDITIONAL_VERSIONS "3.9;3.8;3.7;3.6;3.5;3.4" CACHE INTERNAL "") list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}") find_package(PythonLibsNew ${PYBIND11_PYTHON_VERSION} MODULE REQUIRED) list(REMOVE_AT CMAKE_MODULE_PATH -1) include(CheckCXXCompilerFlag) # Warn or error if old variable name used if(PYBIND11_CPP_STANDARD) string(REGEX MATCH [[..$]] VAL "${PYBIND11_CPP_STANDARD}") if(CMAKE_CXX_STANDARD) if(NOT CMAKE_CXX_STANDARD STREQUAL VAL) message(WARNING "CMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD} does not match " "PYBIND11_CPP_STANDARD=${PYBIND11_CPP_STANDARD}, " "please remove PYBIND11_CPP_STANDARD from your cache") endif() else() set(supported_standards 11 14 17 20) if("${VAL}" IN_LIST supported_standards) message(WARNING "USE -DCMAKE_CXX_STANDARD=${VAL} instead of PYBIND11_PYTHON_VERSION") set(CMAKE_CXX_STANDARD ${VAL} CACHE STRING "From PYBIND11_CPP_STANDARD") else() message(FATAL_ERROR "PYBIND11_CPP_STANDARD should be replaced with CMAKE_CXX_STANDARD " "(last two chars: ${VAL} not understood as a valid CXX std)") endif() endif() endif() # Checks whether the given CXX/linker flags can compile and link a cxx file. cxxflags and # linkerflags are lists of flags to use. The result variable is a unique variable name for each set # of flags: the compilation result will be cached base on the result variable. If the flags work, # sets them in cxxflags_out/linkerflags_out internal cache variables (in addition to ${result}). function(_pybind11_return_if_cxx_and_linker_flags_work result cxxflags linkerflags cxxflags_out linkerflags_out) set(CMAKE_REQUIRED_LIBRARIES ${linkerflags}) check_cxx_compiler_flag("${cxxflags}" ${result}) if(${result}) set(${cxxflags_out} "${cxxflags}" CACHE INTERNAL "" FORCE) set(${linkerflags_out} "${linkerflags}" CACHE INTERNAL "" FORCE) endif() endfunction() # Internal: find the appropriate link time optimization flags for this compiler function(_pybind11_add_lto_flags target_name prefer_thin_lto) if(NOT DEFINED PYBIND11_LTO_CXX_FLAGS) set(PYBIND11_LTO_CXX_FLAGS "" CACHE INTERNAL "") set(PYBIND11_LTO_LINKER_FLAGS "" CACHE INTERNAL "") if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang") set(cxx_append "") set(linker_append "") if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT APPLE) # Clang Gold plugin does not support -Os; append -O3 to MinSizeRel builds to override it set(linker_append ";$<$:-O3>") elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU") set(cxx_append ";-fno-fat-lto-objects") endif() if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND prefer_thin_lto) _pybind11_return_if_cxx_and_linker_flags_work( HAS_FLTO_THIN "-flto=thin${cxx_append}" "-flto=thin${linker_append}" PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS) endif() if(NOT HAS_FLTO_THIN) _pybind11_return_if_cxx_and_linker_flags_work( HAS_FLTO "-flto${cxx_append}" "-flto${linker_append}" PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS) endif() elseif(CMAKE_CXX_COMPILER_ID MATCHES "Intel") # Intel equivalent to LTO is called IPO _pybind11_return_if_cxx_and_linker_flags_work( HAS_INTEL_IPO "-ipo" "-ipo" PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS) elseif(MSVC) # cmake only interprets libraries as linker flags when they start with a - (otherwise it # converts /LTCG to \LTCG as if it was a Windows path). Luckily MSVC supports passing flags # with - instead of /, even if it is a bit non-standard: _pybind11_return_if_cxx_and_linker_flags_work( HAS_MSVC_GL_LTCG "/GL" "-LTCG" PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS) endif() if(PYBIND11_LTO_CXX_FLAGS) message(STATUS "LTO enabled") else() message(STATUS "LTO disabled (not supported by the compiler and/or linker)") endif() endif() # Enable LTO flags if found, except for Debug builds if(PYBIND11_LTO_CXX_FLAGS) set(not_debug "$>") set(cxx_lang "$") target_compile_options(${target_name} PRIVATE "$<$:${PYBIND11_LTO_CXX_FLAGS}>") endif() if(PYBIND11_LTO_LINKER_FLAGS) target_link_libraries(${target_name} PRIVATE "$<${not_debug}:${PYBIND11_LTO_LINKER_FLAGS}>") endif() endfunction() # Build a Python extension module: # pybind11_add_module( [MODULE | SHARED] [EXCLUDE_FROM_ALL] # [NO_EXTRAS] [THIN_LTO] source1 [source2 ...]) # function(pybind11_add_module target_name) set(options MODULE SHARED EXCLUDE_FROM_ALL NO_EXTRAS SYSTEM THIN_LTO) cmake_parse_arguments(PARSE_ARGV 1 ARG "${options}" "" "") if(ARG_MODULE AND ARG_SHARED) message(FATAL_ERROR "Can't be both MODULE and SHARED") elseif(ARG_SHARED) set(lib_type SHARED) else() set(lib_type MODULE) endif() if(ARG_EXCLUDE_FROM_ALL) set(exclude_from_all EXCLUDE_FROM_ALL) else() set(exclude_from_all "") endif() add_library(${target_name} ${lib_type} ${exclude_from_all} ${ARG_UNPARSED_ARGUMENTS}) target_link_libraries(${target_name} PRIVATE pybind11::module) if(ARG_SYSTEM) message( STATUS "Warning: this does not have an effect - use NO_SYSTEM_FROM_IMPORTED if using imported targets" ) endif() # Python debug libraries expose slightly different objects before 3.8 # https://docs.python.org/3.6/c-api/intro.html#debugging-builds # https://stackoverflow.com/questions/39161202/how-to-work-around-missing-pymodule-create2-in-amd64-win-python35-d-lib if(PYTHON_IS_DEBUG) target_compile_definitions(${target_name} PRIVATE Py_DEBUG) endif() # The prefix and extension are provided by FindPythonLibsNew.cmake set_target_properties(${target_name} PROPERTIES PREFIX "${PYTHON_MODULE_PREFIX}") set_target_properties(${target_name} PROPERTIES SUFFIX "${PYTHON_MODULE_EXTENSION}") # -fvisibility=hidden is required to allow multiple modules compiled against # different pybind versions to work properly, and for some features (e.g. # py::module_local). We force it on everything inside the `pybind11` # namespace; also turning it on for a pybind module compilation here avoids # potential warnings or issues from having mixed hidden/non-hidden types. set_target_properties(${target_name} PROPERTIES CXX_VISIBILITY_PRESET "hidden") set_target_properties(${target_name} PROPERTIES CUDA_VISIBILITY_PRESET "hidden") if(ARG_NO_EXTRAS) return() endif() if(CMAKE_VERSION VERSION_LESS 3.9 OR PYBIND11_CLASSIC_LTO) _pybind11_add_lto_flags(${target_name} ${ARG_THIN_LTO}) else() include(CheckIPOSupported) check_ipo_supported( RESULT supported OUTPUT error LANGUAGES CXX) if(supported) set_property(TARGET ${target_name} PROPERTY INTERPROCEDURAL_OPTIMIZATION TRUE) else() message(WARNING "IPO is not supported: ${output}") endif() endif() if(NOT MSVC AND NOT ${CMAKE_BUILD_TYPE} MATCHES Debug|RelWithDebInfo) # Strip unnecessary sections of the binary on Linux/Mac OS if(CMAKE_STRIP) if(APPLE) add_custom_command( TARGET ${target_name} POST_BUILD COMMAND ${CMAKE_STRIP} -x $) else() add_custom_command( TARGET ${target_name} POST_BUILD COMMAND ${CMAKE_STRIP} $) endif() endif() endif() if(MSVC) # /MP enables multithreaded builds (relevant when there are many files), /bigobj is # needed for bigger binding projects due to the limit to 64k addressable sections target_compile_options(${target_name} PRIVATE /bigobj) if(CMAKE_VERSION VERSION_LESS 3.11) target_compile_options(${target_name} PRIVATE $<$>:/MP>) else() # Only set these options for C++ files. This is important so that, for # instance, projects that include other types of source files like CUDA # .cu files don't get these options propagated to nvcc since that would # cause the build to fail. target_compile_options(${target_name} PRIVATE $<$>:$<$:/MP>>) endif() endif() endfunction()