pybind11/tools/pybind11Tools.cmake
2020-07-30 20:27:55 -04:00

216 lines
8.6 KiB
CMake

# 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 3.7)
# VERSION 3.7...3.18, but some versions of VS have a patched CMake 3.11
# that do not work properly with this syntax, so using the following workaround:
if(${CMAKE_VERSION} VERSION_LESS 3.18)
cmake_policy(VERSION ${CMAKE_MAJOR_VERSION}.${CMAKE_MINOR_VERSION})
else()
cmake_policy(VERSION 3.18)
endif()
# 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 "")
find_package(PythonLibsNew ${PYBIND11_PYTHON_VERSION} REQUIRED)
include(CheckCXXCompilerFlag)
include(CMakeParseArguments)
# Warn or error if old variable name used
if(PYBIND11_CPP_STANDARD)
if(NOT CMAKE_CXX_STANDARD)
string(REGEX MATCH
[=[..^]=]
VAL
"${PYBIND11_CPP_STANDARD}")
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})
else()
message(FATAL_ERROR "PYBIND11_CPP_STANDARD should be replaced with CMAKE_CXX_STANDARD")
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 ";$<$<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)
set(not_debug "$<NOT:$<CONFIG:Debug>>")
set(cxx_lang "$<COMPILE_LANGUAGE:CXX>")
target_compile_options(${target_name} PRIVATE "$<$<AND:${not_debug},${cxx_lang}>:${PYBIND11_LTO_CXX_FLAGS}>")
endif()
if (PYBIND11_LTO_LINKER_FLAGS)
target_link_libraries(${target_name} PRIVATE "$<${not_debug}:${PYBIND11_LTO_LINKER_FLAGS}>")
endif()
endfunction()
# Build a Python extension module:
# pybind11_add_module(<name> [MODULE | SHARED] [EXCLUDE_FROM_ALL]
# [NO_EXTRAS] [THIN_LTO] source1 [source2 ...])
#
function(pybind11_add_module target_name)
set(options MODULE SHARED EXCLUDE_FROM_ALL NO_EXTRAS SYSTEM THIN_LTO)
cmake_parse_arguments(ARG "${options}" "" "" ${ARGN})
if(ARG_MODULE AND ARG_SHARED)
message(FATAL_ERROR "Can't be both MODULE and SHARED")
elseif(ARG_SHARED)
set(lib_type SHARED)
else()
set(lib_type MODULE)
endif()
if(ARG_EXCLUDE_FROM_ALL)
set(exclude_from_all EXCLUDE_FROM_ALL)
else()
set(exclude_from_all "")
endif()
add_library(${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)
if(supported)
set_property(
TARGET
${target_name}
PROPERTY
INTERPROCEDURAL_OPTIMIZATION TRUE
)
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 $<TARGET_FILE:${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(${target_name} PRIVATE /bigobj)
if(CMAKE_VERSION VERSION_LESS 3.11)
target_compile_options(${target_name} PRIVATE $<$<NOT:$<CONFIG:Debug>>:/MP>)
else()
# Only set these options for C++ files. This is important so that, for
# instance, projects that include other types of source files like CUDA
# .cu files don't get these options propagated to nvcc since that would
# cause the build to fail.
target_compile_options(${target_name} PRIVATE $<$<NOT:$<CONFIG:Debug>>:$<$<COMPILE_LANGUAGE:CXX>:/MP>>)
endif()
endif()
endfunction()