feat: new FindPython support (#2370)
* feat: FindPython support
* refactor: rename to PYBIND11_FINDPYTHON
* docs: Caps fixes
* feat: NOPYTHON mode
* test: check simple call
* docs: add changelog/upgrade guide
* feat: Support Python3 and Python2
* refactor: Use targets in tests
* fix: support CMake 3.4+
* feat: classic search also finds virtual environments
* docs: some updates from @wjakob's review
* fix: wrong name for QUIET mode variable, reported by @skoslowski
* refactor: cleaner output messaging
* fix: support debug Python's in FindPython mode too
* fixup! refactor: cleaner output messaging
* fix: missing pybind11_FOUND and pybind11_INCLUDE_DIR restored to subdir mode
* fix: nicer reporting of Python / PyPy
* fix: out-of-order variable fix
* docs: minor last-minute cleanup
diff --git a/tools/pybind11Common.cmake b/tools/pybind11Common.cmake
new file mode 100644
index 0000000..f058451
--- /dev/null
+++ b/tools/pybind11Common.cmake
@@ -0,0 +1,296 @@
+#[======================================================[.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::python2_no_register - Avoid warning/error with Python 2 + C++14/7
+ pybind11::windows_extras - MSVC bigobj and mp for building multithreaded
+
+Adds the following functions::
+
+ pybind11_strip(target) - strip target after building on linux/macOS
+
+
+#]======================================================]
+
+# CMake 3.10 has an include_guard command, but we can't use that yet
+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()
+
+# --------------------- 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)
+
+# ----------------------- no register ----------------------
+
+# Workaround for Python 2.7 and C++17 (C++14 as a warning) incompatibility
+# This adds the flags -Wno-register and -Wno-deprecated-register if the compiler
+# is Clang 3.9+ or AppleClang and the compile language is CXX, or /wd5033 for MSVC (all languages,
+# since MSVC didn't recognize COMPILE_LANGUAGE until CMake 3.11+).
+
+add_library(pybind11::python2_no_register INTERFACE IMPORTED ${optional_global})
+set(clang_4plus
+ "$<AND:$<CXX_COMPILER_ID:Clang>,$<NOT:$<VERSION_LESS:$<CXX_COMPILER_VERSION>,3.9>>>")
+set(no_register "$<OR:${clang_4plus},$<CXX_COMPILER_ID:AppleClang>>")
+
+if(MSVC AND CMAKE_VERSION VERSION_LESS 3.11)
+ set(cxx_no_register "${no_register}")
+else()
+ set(cxx_no_register "$<AND:$<COMPILE_LANGUAGE:CXX>,${no_register}>")
+endif()
+
+set(msvc "$<CXX_COMPILER_ID:MSVC>")
+
+set_property(
+ TARGET pybind11::python2_no_register
+ PROPERTY INTERFACE_COMPILE_OPTIONS
+ "$<${cxx_no_register}:-Wno-register;-Wno-deprecated-register>" "$<${msvc}:/wd5033>")
+
+# --------------------------- link helper ---------------------------
+
+add_library(pybind11::python_link_helper IMPORTED INTERFACE ${optional_global})
+
+if(CMAKE_VERSION VERSION_LESS 3.13)
+ # In CMake 3.11+, you can set INTERFACE properties via the normal methods, and
+ # this would be simpler.
+ set_property(
+ TARGET pybind11::python_link_helper
+ APPEND
+ PROPERTY INTERFACE_LINK_LIBRARIES "$<$<PLATFORM_ID:Darwin>:-undefined dynamic_lookup>")
+else()
+ # link_options was added in 3.13+
+ # This is safer, because you are ensured the deduplication pass in CMake will not consider
+ # these separate and remove one but not the other.
+ set_property(
+ TARGET pybind11::python_link_helper
+ APPEND
+ PROPERTY INTERFACE_LINK_OPTIONS "$<$<PLATFORM_ID:Darwin>:LINKER:-undefined,dynamic_lookup>")
+endif()
+
+# ------------------------ Windows extras -------------------------
+
+add_library(pybind11::windows_extras IMPORTED INTERFACE ${optional_global})
+
+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
+ set_property(
+ TARGET pybind11::windows_extras
+ APPEND
+ PROPERTY INTERFACE_COMPILE_OPTIONS /bigobj)
+
+ 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:$<CONFIG:Debug>>:$<$<COMPILE_LANGUAGE:CXX>:/MP>>)
+ endif()
+endif()
+
+# ----------------------- Legacy option --------------------------
+
+# Warn or error if old variable name used
+if(PYBIND11_CPP_STANDARD)
+ string(REGEX MATCH [[..$]] 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_PYTHON_VERSION")
+ 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()
+
+# --------------------- 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(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()
+
+ # Enable LTO flags if found, except for Debug builds
+ if(PYBIND11_LTO_CXX_FLAGS)
+ set(not_debug "$<NOT:$<CONFIG:Debug>>")
+ set(cxx_lang "$<COMPILE_LANGUAGE:CXX>")
+ if(MSVC AND CMAKE_VERSION VERSION_LESS 3.11)
+ set(genex "${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/Mac OS
+ 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()