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# tools/pybind11Tools.cmake -- Build system for the pybind11 modules
#
# Copyright (c) 2015 Wenzel Jakob <wenzel@inf.ethz.ch>
#
# 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)
function(select_cxx_standard)
if(NOT MSVC AND NOT PYBIND11_CPP_STANDARD)
check_cxx_compiler_flag("-std=c++14" HAS_CPP14_FLAG)
check_cxx_compiler_flag("-std=c++11" HAS_CPP11_FLAG)
if (HAS_CPP14_FLAG)
set(PYBIND11_CPP_STANDARD -std=c++14)
elseif (HAS_CPP11_FLAG)
set(PYBIND11_CPP_STANDARD -std=c++11)
else()
message(FATAL_ERROR "Unsupported compiler -- pybind11 requires C++11 support!")
endif()
set(PYBIND11_CPP_STANDARD ${PYBIND11_CPP_STANDARD} CACHE STRING
"C++ standard flag, e.g. -std=c++11 or -std=c++14. Defaults to latest available." FORCE)
endif()
endfunction()
# 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 ";$<$<CONFIG:MinSizeRel>:-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(${target_name} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:${PYBIND11_LTO_CXX_FLAGS}>")
endif()
if (PYBIND11_LTO_LINKER_FLAGS)
target_link_libraries(${target_name} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:${PYBIND11_LTO_LINKER_FLAGS}>")
endif()
endfunction()
# Build a Python extension module:
# pybind11_add_module(<name> [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 ${PYTHON_INCLUDE_DIRS})
# The prefix and extension are provided by FindPythonLibsNew.cmake
set_target_properties(${target_name} PROPERTIES PREFIX "${PYTHON_MODULE_PREFIX}")
set_target_properties(${target_name} PROPERTIES SUFFIX "${PYTHON_MODULE_EXTENSION}")
if(WIN32 OR CYGWIN)
# Link against the Python shared library on Windows
target_link_libraries(${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(${target_name} PROPERTIES MACOSX_RPATH ON)
endif()
endif()
select_cxx_standard()
if(NOT MSVC)
# Make sure C++11/14 are enabled
target_compile_options(${target_name} PUBLIC ${PYBIND11_CPP_STANDARD})
endif()
if(ARG_NO_EXTRAS)
return()
endif()
_pybind11_add_lto_flags(${target_name} ${ARG_THIN_LTO})
if (NOT MSVC AND NOT ${CMAKE_BUILD_TYPE} MATCHES Debug)
# Set the default symbol visibility to hidden (very important to obtain small binaries)
target_compile_options(${target_name} PRIVATE "-fvisibility=hidden")
# 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 $<TARGET_FILE:${target_name}>)
else()
add_custom_command(TARGET ${target_name} POST_BUILD
COMMAND ${CMAKE_STRIP} $<TARGET_FILE:${target_name}>)
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()