# 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. cmake_minimum_required(VERSION 2.8.12) # 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() set(Python_ADDITIONAL_VERSIONS 3.7 3.6 3.5 3.4) find_package(PythonLibsNew ${PYBIND11_PYTHON_VERSION} REQUIRED) include(CheckCXXCompilerFlag) include(CMakeParseArguments) if(NOT PYBIND11_CPP_STANDARD AND NOT CMAKE_CXX_STANDARD) if(NOT MSVC) check_cxx_compiler_flag("-std=c++14" HAS_CPP14_FLAG) if (HAS_CPP14_FLAG) set(PYBIND11_CPP_STANDARD -std=c++14) else() check_cxx_compiler_flag("-std=c++11" HAS_CPP11_FLAG) if (HAS_CPP11_FLAG) set(PYBIND11_CPP_STANDARD -std=c++11) else() message(FATAL_ERROR "Unsupported compiler -- pybind11 requires C++11 support!") endif() endif() elseif(MSVC) set(PYBIND11_CPP_STANDARD /std:c++14) endif() set(PYBIND11_CPP_STANDARD ${PYBIND11_CPP_STANDARD} CACHE STRING "C++ standard flag, e.g. -std=c++11, -std=c++14, /std:c++14. Defaults to C++14 mode." FORCE) 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) target_compile_options(${target_name} PRIVATE "$<$>:${PYBIND11_LTO_CXX_FLAGS}>") endif() if (PYBIND11_LTO_LINKER_FLAGS) target_link_libraries(${target_name} PRIVATE "$<$>:${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 THIN_LTO) cmake_parse_arguments(ARG "${options}" "" "" ${ARGN}) if(ARG_MODULE AND ARG_SHARED) message(FATAL_ERROR "Can't be both MODULE and SHARED") elseif(ARG_SHARED) set(lib_type SHARED) else() set(lib_type MODULE) endif() if(ARG_EXCLUDE_FROM_ALL) set(exclude_from_all EXCLUDE_FROM_ALL) endif() add_library(${target_name} ${lib_type} ${exclude_from_all} ${ARG_UNPARSED_ARGUMENTS}) target_include_directories(${target_name} PRIVATE ${PYBIND11_INCLUDE_DIR} # from project CMakeLists.txt PRIVATE ${pybind11_INCLUDE_DIR} # from pybind11Config PRIVATE ${PYTHON_INCLUDE_DIRS}) # Python debug libraries expose slightly different objects # https://docs.python.org/3.6/c-api/intro.html#debugging-builds # https://stackoverflow.com/questions/39161202/how-to-work-around-missing-pymodule-create2-in-amd64-win-python35-d-lib if(PYTHON_IS_DEBUG) target_compile_definitions(${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(${target_name} PROPERTIES CXX_VISIBILITY_PRESET "hidden") if(WIN32 OR CYGWIN) # Link against the Python shared library on Windows target_link_libraries(${target_name} PRIVATE ${PYTHON_LIBRARIES}) elseif(APPLE) # It's quite common to have multiple copies of the same Python version # installed on one's system. E.g.: one copy from the OS and another copy # that's statically linked into an application like Blender or Maya. # If we link our plugin library against the OS Python here and import it # into Blender or Maya later on, this will cause segfaults when multiple # conflicting Python instances are active at the same time (even when they # are of the same version). # Windows is not affected by this issue since it handles DLL imports # differently. The solution for Linux and Mac OS is simple: we just don't # link against the Python library. The resulting shared library will have # missing symbols, but that's perfectly fine -- they will be resolved at # import time. target_link_libraries(${target_name} PRIVATE "-undefined dynamic_lookup") if(ARG_SHARED) # Suppress CMake >= 3.0 warning for shared libraries set_target_properties(${target_name} PROPERTIES MACOSX_RPATH ON) endif() endif() # Make sure C++11/14 are enabled target_compile_options(${target_name} PUBLIC ${PYBIND11_CPP_STANDARD}) if(ARG_NO_EXTRAS) return() endif() _pybind11_add_lto_flags(${target_name} ${ARG_THIN_LTO}) if (NOT MSVC AND NOT ${CMAKE_BUILD_TYPE} MATCHES Debug) # 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 /MP /bigobj) endif() endfunction()