Files
pybind11/tools/pybind11Common.cmake
Henry Schreiner 692b031ac5 fix(cmake): keep CMP0190 auto-default in add_subdirectory builds
The previous commit's `NOT DEFINED PYBIND11_USE_CROSSCOMPILING` guard
broke the intended auto-default for top-level / add_subdirectory builds:
CMakeLists.txt runs `option(PYBIND11_USE_CROSSCOMPILING ... OFF)` before
including pybind11Common.cmake, so the variable is already defined (OFF)
and the CMP0190 default never applied.

Capture, before the option() call, whether the project set the value
itself, and let pybind11Common.cmake apply its default unless the value
was set explicitly. This keeps both the emulator override fix and the
CMP0190 auto-default for subdirectory consumers.

Assisted-by: ClaudeCode:claude-opus-4.8
2026-06-24 00:55:38 -04:00

465 lines
17 KiB
CMake

#[======================================================[.rst
Adds the following targets::
pybind11::pybind11 - link to Python headers and pybind11::headers
pybind11::module - Adds module links
pybind11::embed - Adds embed links
pybind11::lto - Link time optimizations (only if CMAKE_INTERPROCEDURAL_OPTIMIZATION is not set)
pybind11::thin_lto - Link time optimizations (only if CMAKE_INTERPROCEDURAL_OPTIMIZATION is not set)
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.
#]======================================================]
# 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)
include_guard(GLOBAL)
set(optional_global GLOBAL)
else()
include_guard(DIRECTORY)
set(optional_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)")
# CMP0190 prohibits calling FindPython with both Interpreter and Development components
# when cross-compiling, unless the CMAKE_CROSSCOMPILING_EMULATOR variable is defined.
# Default PYBIND11_USE_CROSSCOMPILING to ON in that case, but never override a value the
# project set explicitly (e.g. Emscripten/Pyodide defines an emulator yet still wants it ON).
# PYBIND11_USE_CROSSCOMPILING is undefined for find_package() consumers, but our own
# CMakeLists.txt always defines it via option(); _PYBIND11_USE_CROSSCOMPILING_DEFAULTED tells
# us whether that came from the project or from the option() default.
if(CMAKE_VERSION VERSION_GREATER_EQUAL "4.1"
AND NOT DEFINED CMAKE_CROSSCOMPILING_EMULATOR
AND (NOT DEFINED PYBIND11_USE_CROSSCOMPILING OR _PYBIND11_USE_CROSSCOMPILING_DEFAULTED))
cmake_policy(GET CMP0190 _pybind11_cmp0190)
if(_pybind11_cmp0190 STREQUAL "NEW")
set(PYBIND11_USE_CROSSCOMPILING "ON")
endif()
endif()
if(CMAKE_CROSSCOMPILING AND PYBIND11_USE_CROSSCOMPILING)
set(_PYBIND11_CROSSCOMPILING
ON
CACHE INTERNAL "")
else()
set(_PYBIND11_CROSSCOMPILING
OFF
CACHE INTERNAL "")
endif()
# --------------------- 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)
# -------------- emscripten requires exceptions enabled -------------
# _pybind11_no_exceptions is a private mechanism to disable this addition.
# Please open an issue if you need to use it; it will be removed if no one
# needs it.
if(CMAKE_SYSTEM_NAME MATCHES Emscripten AND NOT _pybind11_no_exceptions)
if(is_config)
set(_tmp_config_target pybind11::pybind11_headers)
else()
set(_tmp_config_target pybind11_headers)
endif()
set_property(
TARGET ${_tmp_config_target}
APPEND
PROPERTY INTERFACE_LINK_OPTIONS -fexceptions)
set_property(
TARGET ${_tmp_config_target}
APPEND
PROPERTY INTERFACE_COMPILE_OPTIONS -fexceptions)
unset(_tmp_config_target)
endif()
# --------------------------- link helper ---------------------------
add_library(pybind11::python_link_helper IMPORTED INTERFACE ${optional_global})
set_property(
TARGET pybind11::python_link_helper
APPEND
PROPERTY INTERFACE_LINK_OPTIONS
"$<$<PLATFORM_ID:Darwin,iOS,tvOS,watchOS,visionOS>:LINKER:-undefined,dynamic_lookup>")
# ------------------------ 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
# 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()
# ----------------------- 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: ${VAL} not understood as a valid CXX std)")
endif()
endif()
endif()
# --------------------- Python specifics -------------------------
# CMake 3.27 removes the classic FindPythonInterp if CMP0148 is NEW
if(CMAKE_VERSION VERSION_LESS "3.27")
set(_pybind11_missing_old_python "OLD")
else()
cmake_policy(GET CMP0148 _pybind11_missing_old_python)
endif()
# Check to see which Python mode we are in, new, old, or no python
if(PYBIND11_NOPYTHON)
set(_pybind11_nopython ON)
# We won't use new FindPython if PYBIND11_FINDPYTHON is defined and falselike
# Otherwise, we use if FindPythonLibs is missing or if FindPython was already used
elseif(
(NOT DEFINED PYBIND11_FINDPYTHON
OR PYBIND11_FINDPYTHON STREQUAL "COMPAT"
OR PYBIND11_FINDPYTHON)
AND (_pybind11_missing_old_python STREQUAL "NEW"
OR PYBIND11_FINDPYTHON STREQUAL "COMPAT"
OR PYBIND11_FINDPYTHON
OR Python_FOUND
OR Python3_FOUND
))
# New mode
if(Python_FOUND OR Python3_FOUND)
include("${CMAKE_CURRENT_LIST_DIR}/pybind11NewTools.cmake")
else()
include("${CMAKE_CURRENT_LIST_DIR}/pybind11NewTools.cmake")
if(PYBIND11_FINDPYTHON STREQUAL "COMPAT")
message(
"Using compatibility mode for Python, set PYBIND11_FINDPYTHON to NEW/OLD to silence this message"
)
set(PYTHON_EXECUTABLE "${Python_EXECUTABLE}")
set(PYTHON_INCLUDE_DIR "${Python_INCLUDE_DIR}")
set(Python_INCLUDE_DIRS "${Python_INCLUDE_DIRS}")
set(PYTHON_LIBRARY "${Python_LIBRARY}")
set(PYTHON_LIBRARIES "${Python_LIBRARIES}")
set(PYTHON_VERSION "${Python_VERSION}")
set(PYTHON_VERSION_STRING "${Python_VERSION_STRING}")
set(PYTHON_VERSION_MAJOR "${Python_VERSION_MAJOR}")
set(PYTHON_VERSION_MINOR "${Python_VERSION_MINOR}")
set(PYTHON_VERSION_PATCH "${Python_VERSION_PATCH}")
endif()
endif()
else()
# Classic mode
include("${CMAKE_CURRENT_LIST_DIR}/pybind11Tools.cmake")
endif()
# --------------------- pybind11_find_import -------------------------------
if(NOT _pybind11_nopython AND NOT _PYBIND11_CROSSCOMPILING)
# 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 "
try:
from importlib.metadata import version
except ImportError:
from pkg_resources import get_distribution
def version(s):
return get_distribution(s).version
print(version('${PYPI_NAME}'))
"
RESULT_VARIABLE RESULT_PRESENT
OUTPUT_VARIABLE PKG_VERSION
ERROR_QUIET)
string(STRIP "${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 "${target} disabled (problems with undefined symbols for MinGW for now)")
return()
endif()
if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
set(cxx_append "")
set(linker_append "")
if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT APPLE)
# Clang Gold plugin does not support -Os; append -O3 to MinSizeRel builds to override it
set(linker_append ";$<$<CONFIG:MinSizeRel>:-O3>")
elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU" AND NOT MINGW)
set(cxx_append ";-fno-fat-lto-objects")
endif()
if(prefer_thin_lto)
set(thin "=thin")
else()
set(thin "")
endif()
if(CMAKE_SYSTEM_PROCESSOR MATCHES "ppc64le" OR CMAKE_SYSTEM_PROCESSOR MATCHES "mips64")
# Do nothing
elseif(CMAKE_SYSTEM_NAME MATCHES Emscripten)
# This compile is very costly when cross-compiling, so set this without checking
set(PYBIND11_LTO_CXX_FLAGS "-flto${thin}${cxx_append}")
set(PYBIND11_LTO_LINKER_FLAGS "-flto${thin}${linker_append}")
elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
_pybind11_return_if_cxx_and_linker_flags_work(
HAS_FLTO_THIN "-flto${thin}${cxx_append}" "-flto${thin}${linker_append}"
PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
endif()
if(NOT HAS_FLTO_THIN)
_pybind11_return_if_cxx_and_linker_flags_work(
HAS_FLTO_AUTO "-flto=auto${cxx_append}" "-flto=auto${linker_append}"
PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
endif()
if(NOT HAS_FLTO_AUTO)
_pybind11_return_if_cxx_and_linker_flags_work(
HAS_FLTO "-flto${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 "$<COMPILE_LANGUAGE:CXX>")
set(genex "$<AND:${not_debug},${cxx_lang}>")
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)
set_property(
TARGET ${target}
APPEND
PROPERTY INTERFACE_LINK_OPTIONS "$<${not_debug}:${PYBIND11_LTO_LINKER_FLAGS}>")
endif()
endfunction()
if(NOT DEFINED CMAKE_INTERPROCEDURAL_OPTIMIZATION)
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)
endif()
# ---------------------- 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()