pybind11/tools/pybind11Common.cmake
Wenzel Jakob e076c4513d macOS: disable fixup chains when linking extension modules
On macOS, extension library builds usually rely on the flag ``-undefined
dynamic_lookup`` to get the linker to temporarily accept missing CPython
API symbols. As the name implies, those symbols are then dynamically
resolved when Python imports such an extension library. Binaries
produced in this way are more portable since they don't contain a
hardcoded path to the CPython library. This is critical when
distributing binary wheels on PyPI, etc..

When targeting macOS>=12, XCode recently started to generate a somewhat
ominous warning:

``-undefined dynamic_lookup may not work with chained fixups``

For further detail on what chained fixups are, see the following
informative WWDC
https://developer.apple.com/videos/play/wwdc2022/110362/ (the relevant
part starts about 20mins into the video)

The message that the dynamic resolution functionality became broken.
I reported this to Apple via feedback request FB11767124.

Apple investigated the request and updated the behavior of ``ld``
starting with XCode 14.3b1+: it now disables the fixup chain linker
optimization whenever ``-undefined dynamic_lookup`` is specified. The
feedback from Apple also stated that the parameter
``-Wl,-no_fixup_chains`` should be specified on pre-14.3 XCode versions
to ensure correct behavior.

This commit realizes those changes by passing a flag to *always* disable
fixup chains. Related discussion is available in the CPython repository
(https://github.com/python/cpython/issues/97524).
2023-02-27 13:32:16 +01:00

398 lines
14 KiB
CMake

#[======================================================[.rst
Adds the following targets::
pybind11::pybind11 - link to headers and pybind11
pybind11::module - Adds module links
pybind11::embed - Adds embed links
pybind11::lto - Link time optimizations (manual selection)
pybind11::thin_lto - Link time optimizations (manual selection)
pybind11::python_link_helper - Adds link to Python libraries
pybind11::windows_extras - MSVC bigobj and mp for building multithreaded
pybind11::opt_size - avoid optimizations that increase code size
Adds the following functions::
pybind11_strip(target) - strip target after building on linux/macOS
pybind11_find_import(module) - See if a module is installed.
#]======================================================]
# CMake 3.10 has an include_guard command, but we can't use that yet
# include_guard(global) (pre-CMake 3.10)
if(TARGET pybind11::lto)
return()
endif()
# If we are in subdirectory mode, all IMPORTED targets must be GLOBAL. If we
# are in CONFIG mode, they should be "normal" targets instead.
# In CMake 3.11+ you can promote a target to global after you create it,
# which might be simpler than this check.
get_property(
is_config
TARGET pybind11::headers
PROPERTY IMPORTED)
if(NOT is_config)
set(optional_global GLOBAL)
endif()
# If not run in Python mode, we still would like this to at least
# include pybind11's include directory:
set(pybind11_INCLUDE_DIRS
"${pybind11_INCLUDE_DIR}"
CACHE INTERNAL "Include directory for pybind11 (Python not requested)")
# --------------------- Shared targets ----------------------------
# Build an interface library target:
add_library(pybind11::pybind11 IMPORTED INTERFACE ${optional_global})
set_property(
TARGET pybind11::pybind11
APPEND
PROPERTY INTERFACE_LINK_LIBRARIES pybind11::headers)
# Build a module target:
add_library(pybind11::module IMPORTED INTERFACE ${optional_global})
set_property(
TARGET pybind11::module
APPEND
PROPERTY INTERFACE_LINK_LIBRARIES pybind11::pybind11)
# Build an embed library target:
add_library(pybind11::embed IMPORTED INTERFACE ${optional_global})
set_property(
TARGET pybind11::embed
APPEND
PROPERTY INTERFACE_LINK_LIBRARIES pybind11::pybind11)
# --------------------------- link helper ---------------------------
add_library(pybind11::python_link_helper IMPORTED INTERFACE ${optional_global})
if(CMAKE_VERSION VERSION_LESS 3.13)
# In CMake 3.11+, you can set INTERFACE properties via the normal methods, and
# this would be simpler.
set_property(
TARGET pybind11::python_link_helper
APPEND
PROPERTY INTERFACE_LINK_LIBRARIES
"$<$<PLATFORM_ID:Darwin>:-undefined dynamic_lookup -no_fixup_chains>")
else()
# link_options was added in 3.13+
# This is safer, because you are ensured the deduplication pass in CMake will not consider
# these separate and remove one but not the other.
set_property(
TARGET pybind11::python_link_helper
APPEND
PROPERTY INTERFACE_LINK_OPTIONS
"$<$<PLATFORM_ID:Darwin>:LINKER:-undefined,dynamic_lookup,-no_fixup_chains>")
endif()
# ------------------------ Windows extras -------------------------
add_library(pybind11::windows_extras IMPORTED INTERFACE ${optional_global})
if(MSVC) # That's also clang-cl
# /bigobj is needed for bigger binding projects due to the limit to 64k
# addressable sections
set_property(
TARGET pybind11::windows_extras
APPEND
PROPERTY INTERFACE_COMPILE_OPTIONS $<$<COMPILE_LANGUAGE:CXX>:/bigobj>)
# /MP enables multithreaded builds (relevant when there are many files) for MSVC
if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC") # no Clang no Intel
if(CMAKE_VERSION VERSION_LESS 3.11)
set_property(
TARGET pybind11::windows_extras
APPEND
PROPERTY INTERFACE_COMPILE_OPTIONS $<$<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.
set_property(
TARGET pybind11::windows_extras
APPEND
PROPERTY INTERFACE_COMPILE_OPTIONS
$<$<NOT:$<CONFIG:Debug>>:$<$<COMPILE_LANGUAGE:CXX>:/MP>>)
endif()
endif()
endif()
# ----------------------- Optimize binary size --------------------------
add_library(pybind11::opt_size IMPORTED INTERFACE ${optional_global})
if(MSVC)
set(PYBIND11_OPT_SIZE /Os)
else()
set(PYBIND11_OPT_SIZE -Os)
endif()
set_property(
TARGET pybind11::opt_size
APPEND
PROPERTY INTERFACE_COMPILE_OPTIONS $<$<CONFIG:Release>:${PYBIND11_OPT_SIZE}>
$<$<CONFIG:MinSizeRel>:${PYBIND11_OPT_SIZE}>
$<$<CONFIG:RelWithDebInfo>:${PYBIND11_OPT_SIZE}>)
# ----------------------- Legacy option --------------------------
# Warn or error if old variable name used
if(PYBIND11_CPP_STANDARD)
string(REGEX MATCH [[..$]] VAL "${PYBIND11_CPP_STANDARD}")
if(CMAKE_CXX_STANDARD)
if(NOT CMAKE_CXX_STANDARD STREQUAL VAL)
message(WARNING "CMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD} does not match "
"PYBIND11_CPP_STANDARD=${PYBIND11_CPP_STANDARD}, "
"please remove PYBIND11_CPP_STANDARD from your cache")
endif()
else()
set(supported_standards 11 14 17 20)
if("${VAL}" IN_LIST supported_standards)
message(WARNING "USE -DCMAKE_CXX_STANDARD=${VAL} instead of PYBIND11_CPP_STANDARD")
set(CMAKE_CXX_STANDARD
${VAL}
CACHE STRING "From PYBIND11_CPP_STANDARD")
else()
message(FATAL_ERROR "PYBIND11_CPP_STANDARD should be replaced with CMAKE_CXX_STANDARD "
"(last two chars: ${VAL} not understood as a valid CXX std)")
endif()
endif()
endif()
# --------------------- Python specifics -------------------------
# Check to see which Python mode we are in, new, old, or no python
if(PYBIND11_NOPYTHON)
set(_pybind11_nopython ON)
elseif(
PYBIND11_FINDPYTHON
OR Python_FOUND
OR Python2_FOUND
OR Python3_FOUND)
# New mode
include("${CMAKE_CURRENT_LIST_DIR}/pybind11NewTools.cmake")
else()
# Classic mode
include("${CMAKE_CURRENT_LIST_DIR}/pybind11Tools.cmake")
endif()
# --------------------- pybind11_find_import -------------------------------
if(NOT _pybind11_nopython)
# Check to see if modules are importable. Use REQUIRED to force an error if
# one of the modules is not found. <package_name>_FOUND will be set if the
# package was found (underscores replace dashes if present). QUIET will hide
# the found message, and VERSION will require a minimum version. A successful
# find will cache the result.
function(pybind11_find_import PYPI_NAME)
# CMake variables need underscores (PyPI doesn't care)
string(REPLACE "-" "_" NORM_PYPI_NAME "${PYPI_NAME}")
# Return if found previously
if(${NORM_PYPI_NAME}_FOUND)
return()
endif()
set(options "REQUIRED;QUIET")
set(oneValueArgs "VERSION")
cmake_parse_arguments(ARG "${options}" "${oneValueArgs}" "" ${ARGN})
if(ARG_REQUIRED)
set(status_level FATAL_ERROR)
else()
set(status_level WARNING)
endif()
execute_process(
COMMAND
${${_Python}_EXECUTABLE} -c
"from pkg_resources import get_distribution; print(get_distribution('${PYPI_NAME}').version)"
RESULT_VARIABLE RESULT_PRESENT
OUTPUT_VARIABLE PKG_VERSION
ERROR_QUIET)
string(STRIP "${PKG_VERSION}" PKG_VERSION)
# If a result is present, this failed
if(RESULT_PRESENT)
set(${NORM_PYPI_NAME}_FOUND
${NORM_PYPI_NAME}-NOTFOUND
CACHE INTERNAL "")
# Always warn or error
message(
${status_level}
"Missing: ${PYPI_NAME} ${ARG_VERSION}\nTry: ${${_Python}_EXECUTABLE} -m pip install ${PYPI_NAME}"
)
else()
if(ARG_VERSION AND PKG_VERSION VERSION_LESS ARG_VERSION)
message(
${status_level}
"Version incorrect: ${PYPI_NAME} ${PKG_VERSION} found, ${ARG_VERSION} required - try upgrading"
)
else()
set(${NORM_PYPI_NAME}_FOUND
YES
CACHE INTERNAL "")
set(${NORM_PYPI_NAME}_VERSION
${PKG_VERSION}
CACHE INTERNAL "")
endif()
if(NOT ARG_QUIET)
message(STATUS "Found ${PYPI_NAME} ${PKG_VERSION}")
endif()
endif()
if(NOT ARG_VERSION OR (NOT PKG_VERSION VERSION_LESS ARG_VERSION))
# We have successfully found a good version, cache to avoid calling again.
endif()
endfunction()
endif()
# --------------------- LTO -------------------------------
include(CheckCXXCompilerFlag)
# 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}"
PARENT_SCOPE)
set(${linkerflags_out}
"${linkerflags}"
PARENT_SCOPE)
endif()
endfunction()
function(_pybind11_generate_lto target prefer_thin_lto)
if(MINGW)
message(STATUS "${target} disabled (problems with undefined symbols for MinGW for now)")
return()
endif()
if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
set(cxx_append "")
set(linker_append "")
if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT APPLE)
# Clang Gold plugin does not support -Os; append -O3 to MinSizeRel builds to override it
set(linker_append ";$<$<CONFIG:MinSizeRel>:-O3>")
elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU" AND NOT MINGW)
set(cxx_append ";-fno-fat-lto-objects")
endif()
if(CMAKE_SYSTEM_PROCESSOR MATCHES "ppc64le" OR CMAKE_SYSTEM_PROCESSOR MATCHES "mips64")
set(NO_FLTO_ARCH TRUE)
else()
set(NO_FLTO_ARCH FALSE)
endif()
if(CMAKE_CXX_COMPILER_ID MATCHES "Clang"
AND prefer_thin_lto
AND NOT NO_FLTO_ARCH)
_pybind11_return_if_cxx_and_linker_flags_work(
HAS_FLTO_THIN "-flto=thin${cxx_append}" "-flto=thin${linker_append}"
PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
endif()
if(NOT HAS_FLTO_THIN AND NOT NO_FLTO_ARCH)
_pybind11_return_if_cxx_and_linker_flags_work(
HAS_FLTO "-flto${cxx_append}" "-flto${linker_append}" PYBIND11_LTO_CXX_FLAGS
PYBIND11_LTO_LINKER_FLAGS)
endif()
elseif(CMAKE_CXX_COMPILER_ID MATCHES "IntelLLVM")
# IntelLLVM equivalent to LTO is called IPO; also IntelLLVM is WIN32/UNIX
# WARNING/HELP WANTED: This block of code is currently not covered by pybind11 GitHub Actions!
if(WIN32)
_pybind11_return_if_cxx_and_linker_flags_work(
HAS_INTEL_IPO "-Qipo" "-Qipo" PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
else()
_pybind11_return_if_cxx_and_linker_flags_work(
HAS_INTEL_IPO "-ipo" "-ipo" PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
endif()
elseif(CMAKE_CXX_COMPILER_ID MATCHES "Intel")
# Intel equivalent to LTO is called IPO
_pybind11_return_if_cxx_and_linker_flags_work(HAS_INTEL_IPO "-ipo" "-ipo"
PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
elseif(MSVC)
# cmake only interprets libraries as linker flags when they start with a - (otherwise it
# converts /LTCG to \LTCG as if it was a Windows path). Luckily MSVC supports passing flags
# with - instead of /, even if it is a bit non-standard:
_pybind11_return_if_cxx_and_linker_flags_work(HAS_MSVC_GL_LTCG "/GL" "-LTCG"
PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
endif()
# Enable LTO flags if found, except for Debug builds
if(PYBIND11_LTO_CXX_FLAGS)
# CONFIG takes multiple values in CMake 3.19+, until then we have to use OR
set(is_debug "$<OR:$<CONFIG:Debug>,$<CONFIG:RelWithDebInfo>>")
set(not_debug "$<NOT:${is_debug}>")
set(cxx_lang "$<COMPILE_LANGUAGE:CXX>")
if(MSVC AND CMAKE_VERSION VERSION_LESS 3.11)
set(genex "${not_debug}")
else()
set(genex "$<AND:${not_debug},${cxx_lang}>")
endif()
set_property(
TARGET ${target}
APPEND
PROPERTY INTERFACE_COMPILE_OPTIONS "$<${genex}:${PYBIND11_LTO_CXX_FLAGS}>")
if(CMAKE_PROJECT_NAME STREQUAL "pybind11")
message(STATUS "${target} enabled")
endif()
else()
if(CMAKE_PROJECT_NAME STREQUAL "pybind11")
message(STATUS "${target} disabled (not supported by the compiler and/or linker)")
endif()
endif()
if(PYBIND11_LTO_LINKER_FLAGS)
if(CMAKE_VERSION VERSION_LESS 3.11)
set_property(
TARGET ${target}
APPEND
PROPERTY INTERFACE_LINK_LIBRARIES "$<${not_debug}:${PYBIND11_LTO_LINKER_FLAGS}>")
else()
set_property(
TARGET ${target}
APPEND
PROPERTY INTERFACE_LINK_OPTIONS "$<${not_debug}:${PYBIND11_LTO_LINKER_FLAGS}>")
endif()
endif()
endfunction()
add_library(pybind11::lto IMPORTED INTERFACE ${optional_global})
_pybind11_generate_lto(pybind11::lto FALSE)
add_library(pybind11::thin_lto IMPORTED INTERFACE ${optional_global})
_pybind11_generate_lto(pybind11::thin_lto TRUE)
# ---------------------- pybind11_strip -----------------------------
function(pybind11_strip target_name)
# Strip unnecessary sections of the binary on Linux/macOS
if(CMAKE_STRIP)
if(APPLE)
set(x_opt -x)
endif()
add_custom_command(
TARGET ${target_name}
POST_BUILD
COMMAND ${CMAKE_STRIP} ${x_opt} $<TARGET_FILE:${target_name}>)
endif()
endfunction()