1 # tools/pybind11Tools.cmake -- Build system for the pybind11 modules
3 # Copyright (c) 2015 Wenzel Jakob <wenzel@inf.ethz.ch>
5 # All rights reserved. Use of this source code is governed by a
6 # BSD-style license that can be found in the LICENSE file.
8 cmake_minimum_required(VERSION 2.8.12)
10 # Add a CMake parameter for choosing a desired Python version
11 if(NOT PYBIND11_PYTHON_VERSION)
12 set(PYBIND11_PYTHON_VERSION "" CACHE STRING "Python version to use for compiling modules")
15 set(Python_ADDITIONAL_VERSIONS 3.9 3.8 3.7 3.6 3.5 3.4)
16 find_package(PythonLibsNew ${PYBIND11_PYTHON_VERSION} REQUIRED)
18 include(CheckCXXCompilerFlag)
19 include(CMakeParseArguments)
21 if(NOT PYBIND11_CPP_STANDARD AND NOT CMAKE_CXX_STANDARD)
23 check_cxx_compiler_flag("-std=c++14" HAS_CPP14_FLAG)
26 set(PYBIND11_CPP_STANDARD -std=c++14)
28 check_cxx_compiler_flag("-std=c++11" HAS_CPP11_FLAG)
30 set(PYBIND11_CPP_STANDARD -std=c++11)
32 message(FATAL_ERROR "Unsupported compiler -- pybind11 requires C++11 support!")
36 set(PYBIND11_CPP_STANDARD /std:c++14)
39 set(PYBIND11_CPP_STANDARD ${PYBIND11_CPP_STANDARD} CACHE STRING
40 "C++ standard flag, e.g. -std=c++11, -std=c++14, /std:c++14. Defaults to C++14 mode." FORCE)
43 # Checks whether the given CXX/linker flags can compile and link a cxx file. cxxflags and
44 # linkerflags are lists of flags to use. The result variable is a unique variable name for each set
45 # of flags: the compilation result will be cached base on the result variable. If the flags work,
46 # sets them in cxxflags_out/linkerflags_out internal cache variables (in addition to ${result}).
47 function(_pybind11_return_if_cxx_and_linker_flags_work result cxxflags linkerflags cxxflags_out linkerflags_out)
48 set(CMAKE_REQUIRED_LIBRARIES ${linkerflags})
49 check_cxx_compiler_flag("${cxxflags}" ${result})
51 set(${cxxflags_out} "${cxxflags}" CACHE INTERNAL "" FORCE)
52 set(${linkerflags_out} "${linkerflags}" CACHE INTERNAL "" FORCE)
56 # Internal: find the appropriate link time optimization flags for this compiler
57 function(_pybind11_add_lto_flags target_name prefer_thin_lto)
58 if (NOT DEFINED PYBIND11_LTO_CXX_FLAGS)
59 set(PYBIND11_LTO_CXX_FLAGS "" CACHE INTERNAL "")
60 set(PYBIND11_LTO_LINKER_FLAGS "" CACHE INTERNAL "")
62 if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
65 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT APPLE)
66 # Clang Gold plugin does not support -Os; append -O3 to MinSizeRel builds to override it
67 set(linker_append ";$<$<CONFIG:MinSizeRel>:-O3>")
68 elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
69 set(cxx_append ";-fno-fat-lto-objects")
72 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND prefer_thin_lto)
73 _pybind11_return_if_cxx_and_linker_flags_work(HAS_FLTO_THIN
74 "-flto=thin${cxx_append}" "-flto=thin${linker_append}"
75 PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
78 if (NOT HAS_FLTO_THIN)
79 _pybind11_return_if_cxx_and_linker_flags_work(HAS_FLTO
80 "-flto${cxx_append}" "-flto${linker_append}"
81 PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
83 elseif (CMAKE_CXX_COMPILER_ID MATCHES "Intel")
84 # Intel equivalent to LTO is called IPO
85 _pybind11_return_if_cxx_and_linker_flags_work(HAS_INTEL_IPO
86 "-ipo" "-ipo" PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
88 # cmake only interprets libraries as linker flags when they start with a - (otherwise it
89 # converts /LTCG to \LTCG as if it was a Windows path). Luckily MSVC supports passing flags
90 # with - instead of /, even if it is a bit non-standard:
91 _pybind11_return_if_cxx_and_linker_flags_work(HAS_MSVC_GL_LTCG
92 "/GL" "-LTCG" PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
95 if (PYBIND11_LTO_CXX_FLAGS)
96 message(STATUS "LTO enabled")
98 message(STATUS "LTO disabled (not supported by the compiler and/or linker)")
102 # Enable LTO flags if found, except for Debug builds
103 if (PYBIND11_LTO_CXX_FLAGS)
104 target_compile_options(${target_name} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:${PYBIND11_LTO_CXX_FLAGS}>")
106 if (PYBIND11_LTO_LINKER_FLAGS)
107 target_link_libraries(${target_name} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:${PYBIND11_LTO_LINKER_FLAGS}>")
111 # Build a Python extension module:
112 # pybind11_add_module(<name> [MODULE | SHARED] [EXCLUDE_FROM_ALL]
113 # [NO_EXTRAS] [SYSTEM] [THIN_LTO] source1 [source2 ...])
115 function(pybind11_add_module target_name)
116 set(options MODULE SHARED EXCLUDE_FROM_ALL NO_EXTRAS SYSTEM THIN_LTO)
117 cmake_parse_arguments(ARG "${options}" "" "" ${ARGN})
119 if(ARG_MODULE AND ARG_SHARED)
120 message(FATAL_ERROR "Can't be both MODULE and SHARED")
127 if(ARG_EXCLUDE_FROM_ALL)
128 set(exclude_from_all EXCLUDE_FROM_ALL)
131 add_library(${target_name} ${lib_type} ${exclude_from_all} ${ARG_UNPARSED_ARGUMENTS})
134 set(inc_isystem SYSTEM)
137 target_include_directories(${target_name} ${inc_isystem}
138 PRIVATE ${PYBIND11_INCLUDE_DIR} # from project CMakeLists.txt
139 PRIVATE ${pybind11_INCLUDE_DIR} # from pybind11Config
140 PRIVATE ${PYTHON_INCLUDE_DIRS})
142 # Python debug libraries expose slightly different objects
143 # https://docs.python.org/3.6/c-api/intro.html#debugging-builds
144 # https://stackoverflow.com/questions/39161202/how-to-work-around-missing-pymodule-create2-in-amd64-win-python35-d-lib
146 target_compile_definitions(${target_name} PRIVATE Py_DEBUG)
149 # The prefix and extension are provided by FindPythonLibsNew.cmake
150 set_target_properties(${target_name} PROPERTIES PREFIX "${PYTHON_MODULE_PREFIX}")
151 set_target_properties(${target_name} PROPERTIES SUFFIX "${PYTHON_MODULE_EXTENSION}")
153 # -fvisibility=hidden is required to allow multiple modules compiled against
154 # different pybind versions to work properly, and for some features (e.g.
155 # py::module_local). We force it on everything inside the `pybind11`
156 # namespace; also turning it on for a pybind module compilation here avoids
157 # potential warnings or issues from having mixed hidden/non-hidden types.
158 set_target_properties(${target_name} PROPERTIES CXX_VISIBILITY_PRESET "hidden")
159 set_target_properties(${target_name} PROPERTIES CUDA_VISIBILITY_PRESET "hidden")
162 # Link against the Python shared library on Windows
163 target_link_libraries(${target_name} PRIVATE ${PYTHON_LIBRARIES})
165 # It's quite common to have multiple copies of the same Python version
166 # installed on one's system. E.g.: one copy from the OS and another copy
167 # that's statically linked into an application like Blender or Maya.
168 # If we link our plugin library against the OS Python here and import it
169 # into Blender or Maya later on, this will cause segfaults when multiple
170 # conflicting Python instances are active at the same time (even when they
171 # are of the same version).
173 # Windows is not affected by this issue since it handles DLL imports
174 # differently. The solution for Linux and Mac OS is simple: we just don't
175 # link against the Python library. The resulting shared library will have
176 # missing symbols, but that's perfectly fine -- they will be resolved at
179 target_link_libraries(${target_name} PRIVATE "-undefined dynamic_lookup")
182 # Suppress CMake >= 3.0 warning for shared libraries
183 set_target_properties(${target_name} PROPERTIES MACOSX_RPATH ON)
187 # Make sure C++11/14 are enabled
188 if(CMAKE_VERSION VERSION_LESS 3.3)
189 target_compile_options(${target_name} PUBLIC ${PYBIND11_CPP_STANDARD})
191 target_compile_options(${target_name} PUBLIC $<$<COMPILE_LANGUAGE:CXX>:${PYBIND11_CPP_STANDARD}>)
198 _pybind11_add_lto_flags(${target_name} ${ARG_THIN_LTO})
200 if (NOT MSVC AND NOT ${CMAKE_BUILD_TYPE} MATCHES Debug|RelWithDebInfo)
201 # Strip unnecessary sections of the binary on Linux/Mac OS
204 add_custom_command(TARGET ${target_name} POST_BUILD
205 COMMAND ${CMAKE_STRIP} -x $<TARGET_FILE:${target_name}>)
207 add_custom_command(TARGET ${target_name} POST_BUILD
208 COMMAND ${CMAKE_STRIP} $<TARGET_FILE:${target_name}>)
214 # /MP enables multithreaded builds (relevant when there are many files), /bigobj is
215 # needed for bigger binding projects due to the limit to 64k addressable sections
216 target_compile_options(${target_name} PRIVATE /bigobj)
217 if(CMAKE_VERSION VERSION_LESS 3.11)
218 target_compile_options(${target_name} PRIVATE $<$<NOT:$<CONFIG:Debug>>:/MP>)
220 # Only set these options for C++ files. This is important so that, for
221 # instance, projects that include other types of source files like CUDA
222 # .cu files don't get these options propagated to nvcc since that would
223 # cause the build to fail.
224 target_compile_options(${target_name} PRIVATE $<$<NOT:$<CONFIG:Debug>>:$<$<COMPILE_LANGUAGE:CXX>:/MP>>)