pybind11Tools.cmake revision 12391:ceeca8b41e4b 
1# tools/pybind11Tools.cmake -- Build system for the pybind11 modules
2#
3# Copyright (c) 2015 Wenzel Jakob <wenzel@inf.ethz.ch>
4#
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.
7
8cmake_minimum_required(VERSION 2.8.12)
9
10# Add a CMake parameter for choosing a desired Python version
11if(NOT PYBIND11_PYTHON_VERSION)
12  set(PYBIND11_PYTHON_VERSION "" CACHE STRING "Python version to use for compiling modules")
13endif()
14
15set(Python_ADDITIONAL_VERSIONS 3.7 3.6 3.5 3.4)
16find_package(PythonLibsNew ${PYBIND11_PYTHON_VERSION} REQUIRED)
17
18include(CheckCXXCompilerFlag)
19include(CMakeParseArguments)
20
21if(NOT PYBIND11_CPP_STANDARD AND NOT CMAKE_CXX_STANDARD)
22  if(NOT MSVC)
23    check_cxx_compiler_flag("-std=c++14" HAS_CPP14_FLAG)
24
25    if (HAS_CPP14_FLAG)
26      set(PYBIND11_CPP_STANDARD -std=c++14)
27    else()
28      check_cxx_compiler_flag("-std=c++11" HAS_CPP11_FLAG)
29      if (HAS_CPP11_FLAG)
30        set(PYBIND11_CPP_STANDARD -std=c++11)
31      else()
32        message(FATAL_ERROR "Unsupported compiler -- pybind11 requires C++11 support!")
33      endif()
34    endif()
35  elseif(MSVC)
36    set(PYBIND11_CPP_STANDARD /std:c++14)
37  endif()
38
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)
41endif()
42
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}).
47function(_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}" ${result})
50  if (${result})
51    set(${cxxflags_out} "${cxxflags}" CACHE INTERNAL "" FORCE)
52    set(${linkerflags_out} "${linkerflags}" CACHE INTERNAL "" FORCE)
53  endif()
54endfunction()
55
56# Internal: find the appropriate link time optimization flags for this compiler
57function(_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 "")
61
62    if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
63      set(cxx_append "")
64      set(linker_append "")
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")
70      endif()
71
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)
76      endif()
77
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)
82      endif()
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)
87    elseif(MSVC)
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)
93    endif()
94
95    if (PYBIND11_LTO_CXX_FLAGS)
96      message(STATUS "LTO enabled")
97    else()
98      message(STATUS "LTO disabled (not supported by the compiler and/or linker)")
99    endif()
100  endif()
101
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>>:${PYBIND11_LTO_CXX_FLAGS}>")
105  endif()
106  if (PYBIND11_LTO_LINKER_FLAGS)
107    target_link_libraries(${target_name} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:${PYBIND11_LTO_LINKER_FLAGS}>")
108  endif()
109endfunction()
110
111# Build a Python extension module:
112# pybind11_add_module(<name> [MODULE | SHARED] [EXCLUDE_FROM_ALL]
113#                     [NO_EXTRAS] [THIN_LTO] source1 [source2 ...])
114#
115function(pybind11_add_module target_name)
116  set(options MODULE SHARED EXCLUDE_FROM_ALL NO_EXTRAS THIN_LTO)
117  cmake_parse_arguments(ARG "${options}" "" "" ${ARGN})
118
119  if(ARG_MODULE AND ARG_SHARED)
120    message(FATAL_ERROR "Can't be both MODULE and SHARED")
121  elseif(ARG_SHARED)
122    set(lib_type SHARED)
123  else()
124    set(lib_type MODULE)
125  endif()
126
127  if(ARG_EXCLUDE_FROM_ALL)
128    set(exclude_from_all EXCLUDE_FROM_ALL)
129  endif()
130
131  add_library(${target_name} ${lib_type} ${exclude_from_all} ${ARG_UNPARSED_ARGUMENTS})
132
133  target_include_directories(${target_name}
134    PRIVATE ${PYBIND11_INCLUDE_DIR}  # from project CMakeLists.txt
135    PRIVATE ${pybind11_INCLUDE_DIR}  # from pybind11Config
136    PRIVATE ${PYTHON_INCLUDE_DIRS})
137
138  # The prefix and extension are provided by FindPythonLibsNew.cmake
139  set_target_properties(${target_name} PROPERTIES PREFIX "${PYTHON_MODULE_PREFIX}")
140  set_target_properties(${target_name} PROPERTIES SUFFIX "${PYTHON_MODULE_EXTENSION}")
141
142  # -fvisibility=hidden is required to allow multiple modules compiled against
143  # different pybind versions to work properly, and for some features (e.g.
144  # py::module_local).  We force it on everything inside the `pybind11`
145  # namespace; also turning it on for a pybind module compilation here avoids
146  # potential warnings or issues from having mixed hidden/non-hidden types.
147  set_target_properties(${target_name} PROPERTIES CXX_VISIBILITY_PRESET "hidden")
148
149  if(WIN32 OR CYGWIN)
150    # Link against the Python shared library on Windows
151    target_link_libraries(${target_name} PRIVATE ${PYTHON_LIBRARIES})
152  elseif(APPLE)
153    # It's quite common to have multiple copies of the same Python version
154    # installed on one's system. E.g.: one copy from the OS and another copy
155    # that's statically linked into an application like Blender or Maya.
156    # If we link our plugin library against the OS Python here and import it
157    # into Blender or Maya later on, this will cause segfaults when multiple
158    # conflicting Python instances are active at the same time (even when they
159    # are of the same version).
160
161    # Windows is not affected by this issue since it handles DLL imports
162    # differently. The solution for Linux and Mac OS is simple: we just don't
163    # link against the Python library. The resulting shared library will have
164    # missing symbols, but that's perfectly fine -- they will be resolved at
165    # import time.
166
167    target_link_libraries(${target_name} PRIVATE "-undefined dynamic_lookup")
168
169    if(ARG_SHARED)
170      # Suppress CMake >= 3.0 warning for shared libraries
171      set_target_properties(${target_name} PROPERTIES MACOSX_RPATH ON)
172    endif()
173  endif()
174
175  # Make sure C++11/14 are enabled
176  target_compile_options(${target_name} PUBLIC ${PYBIND11_CPP_STANDARD})
177
178  if(ARG_NO_EXTRAS)
179    return()
180  endif()
181
182  _pybind11_add_lto_flags(${target_name} ${ARG_THIN_LTO})
183
184  if (NOT MSVC AND NOT ${CMAKE_BUILD_TYPE} MATCHES Debug)
185    # Strip unnecessary sections of the binary on Linux/Mac OS
186    if(CMAKE_STRIP)
187      if(APPLE)
188        add_custom_command(TARGET ${target_name} POST_BUILD
189                           COMMAND ${CMAKE_STRIP} -x $<TARGET_FILE:${target_name}>)
190      else()
191        add_custom_command(TARGET ${target_name} POST_BUILD
192                           COMMAND ${CMAKE_STRIP} $<TARGET_FILE:${target_name}>)
193      endif()
194    endif()
195  endif()
196
197  if(MSVC)
198    # /MP enables multithreaded builds (relevant when there are many files), /bigobj is
199    # needed for bigger binding projects due to the limit to 64k addressable sections
200    target_compile_options(${target_name} PRIVATE /MP /bigobj)
201  endif()
202endfunction()
203