pybind11/pybind11/setup_helpers.py
Aaron Gokaslan 9df2f1ff13
maint(precommit): Apply isort (#3195)
* Apply isort

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2021-08-13 12:37:05 -04:00

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Python

# -*- coding: utf-8 -*-
"""
This module provides helpers for C++11+ projects using pybind11.
LICENSE:
Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>, All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""
# IMPORTANT: If you change this file in the pybind11 repo, also review
# setup_helpers.pyi for matching changes.
#
# If you copy this file in, you don't
# need the .pyi file; it's just an interface file for static type checkers.
import contextlib
import os
import platform
import shutil
import sys
import sysconfig
import tempfile
import threading
import warnings
try:
from setuptools import Extension as _Extension
from setuptools.command.build_ext import build_ext as _build_ext
except ImportError:
from distutils.command.build_ext import build_ext as _build_ext
from distutils.extension import Extension as _Extension
import distutils.ccompiler
import distutils.errors
WIN = sys.platform.startswith("win32") and "mingw" not in sysconfig.get_platform()
PY2 = sys.version_info[0] < 3
MACOS = sys.platform.startswith("darwin")
STD_TMPL = "/std:c++{}" if WIN else "-std=c++{}"
# It is recommended to use PEP 518 builds if using this module. However, this
# file explicitly supports being copied into a user's project directory
# standalone, and pulling pybind11 with the deprecated setup_requires feature.
# If you copy the file, remember to add it to your MANIFEST.in, and add the current
# directory into your path if it sits beside your setup.py.
class Pybind11Extension(_Extension):
"""
Build a C++11+ Extension module with pybind11. This automatically adds the
recommended flags when you init the extension and assumes C++ sources - you
can further modify the options yourself.
The customizations are:
* ``/EHsc`` and ``/bigobj`` on Windows
* ``stdlib=libc++`` on macOS
* ``visibility=hidden`` and ``-g0`` on Unix
Finally, you can set ``cxx_std`` via constructor or afterwards to enable
flags for C++ std, and a few extra helper flags related to the C++ standard
level. It is _highly_ recommended you either set this, or use the provided
``build_ext``, which will search for the highest supported extension for
you if the ``cxx_std`` property is not set. Do not set the ``cxx_std``
property more than once, as flags are added when you set it. Set the
property to None to disable the addition of C++ standard flags.
If you want to add pybind11 headers manually, for example for an exact
git checkout, then set ``include_pybind11=False``.
Warning: do not use property-based access to the instance on Python 2 -
this is an ugly old-style class due to Distutils.
"""
# flags are prepended, so that they can be further overridden, e.g. by
# ``extra_compile_args=["-g"]``.
def _add_cflags(self, flags):
self.extra_compile_args[:0] = flags
def _add_ldflags(self, flags):
self.extra_link_args[:0] = flags
def __init__(self, *args, **kwargs):
self._cxx_level = 0
cxx_std = kwargs.pop("cxx_std", 0)
if "language" not in kwargs:
kwargs["language"] = "c++"
include_pybind11 = kwargs.pop("include_pybind11", True)
# Can't use super here because distutils has old-style classes in
# Python 2!
_Extension.__init__(self, *args, **kwargs)
# Include the installed package pybind11 headers
if include_pybind11:
# If using setup_requires, this fails the first time - that's okay
try:
import pybind11
pyinc = pybind11.get_include()
if pyinc not in self.include_dirs:
self.include_dirs.append(pyinc)
except ImportError:
pass
# Have to use the accessor manually to support Python 2 distutils
Pybind11Extension.cxx_std.__set__(self, cxx_std)
cflags = []
ldflags = []
if WIN:
cflags += ["/EHsc", "/bigobj"]
else:
cflags += ["-fvisibility=hidden", "-g0"]
if MACOS:
cflags += ["-stdlib=libc++"]
ldflags += ["-stdlib=libc++"]
self._add_cflags(cflags)
self._add_ldflags(ldflags)
@property
def cxx_std(self):
"""
The CXX standard level. If set, will add the required flags. If left
at 0, it will trigger an automatic search when pybind11's build_ext
is used. If None, will have no effect. Besides just the flags, this
may add a register warning/error fix for Python 2 or macos-min 10.9
or 10.14.
"""
return self._cxx_level
@cxx_std.setter
def cxx_std(self, level):
if self._cxx_level:
warnings.warn("You cannot safely change the cxx_level after setting it!")
# MSVC 2015 Update 3 and later only have 14 (and later 17) modes, so
# force a valid flag here.
if WIN and level == 11:
level = 14
self._cxx_level = level
if not level:
return
cflags = [STD_TMPL.format(level)]
ldflags = []
if MACOS and "MACOSX_DEPLOYMENT_TARGET" not in os.environ:
# C++17 requires a higher min version of macOS. An earlier version
# (10.12 or 10.13) can be set manually via environment variable if
# you are careful in your feature usage, but 10.14 is the safest
# setting for general use. However, never set higher than the
# current macOS version!
current_macos = tuple(int(x) for x in platform.mac_ver()[0].split(".")[:2])
desired_macos = (10, 9) if level < 17 else (10, 14)
macos_string = ".".join(str(x) for x in min(current_macos, desired_macos))
macosx_min = "-mmacosx-version-min=" + macos_string
cflags += [macosx_min]
ldflags += [macosx_min]
if PY2:
if WIN:
# Will be ignored on MSVC 2015, where C++17 is not supported so
# this flag is not valid.
cflags += ["/wd5033"]
elif level >= 17:
cflags += ["-Wno-register"]
elif level >= 14:
cflags += ["-Wno-deprecated-register"]
self._add_cflags(cflags)
self._add_ldflags(ldflags)
# Just in case someone clever tries to multithread
tmp_chdir_lock = threading.Lock()
cpp_cache_lock = threading.Lock()
@contextlib.contextmanager
def tmp_chdir():
"Prepare and enter a temporary directory, cleanup when done"
# Threadsafe
with tmp_chdir_lock:
olddir = os.getcwd()
try:
tmpdir = tempfile.mkdtemp()
os.chdir(tmpdir)
yield tmpdir
finally:
os.chdir(olddir)
shutil.rmtree(tmpdir)
# cf http://bugs.python.org/issue26689
def has_flag(compiler, flag):
"""
Return the flag if a flag name is supported on the
specified compiler, otherwise None (can be used as a boolean).
If multiple flags are passed, return the first that matches.
"""
with tmp_chdir():
fname = "flagcheck.cpp"
with open(fname, "w") as f:
# Don't trigger -Wunused-parameter.
f.write("int main (int, char **) { return 0; }")
try:
compiler.compile([fname], extra_postargs=[flag])
except distutils.errors.CompileError:
return False
return True
# Every call will cache the result
cpp_flag_cache = None
def auto_cpp_level(compiler):
"""
Return the max supported C++ std level (17, 14, or 11). Returns latest on Windows.
"""
if WIN:
return "latest"
global cpp_flag_cache
# If this has been previously calculated with the same args, return that
with cpp_cache_lock:
if cpp_flag_cache:
return cpp_flag_cache
levels = [17, 14, 11]
for level in levels:
if has_flag(compiler, STD_TMPL.format(level)):
with cpp_cache_lock:
cpp_flag_cache = level
return level
msg = "Unsupported compiler -- at least C++11 support is needed!"
raise RuntimeError(msg)
class build_ext(_build_ext): # noqa: N801
"""
Customized build_ext that allows an auto-search for the highest supported
C++ level for Pybind11Extension. This is only needed for the auto-search
for now, and is completely optional otherwise.
"""
def build_extensions(self):
"""
Build extensions, injecting C++ std for Pybind11Extension if needed.
"""
for ext in self.extensions:
if hasattr(ext, "_cxx_level") and ext._cxx_level == 0:
# Python 2 syntax - old-style distutils class
ext.__class__.cxx_std.__set__(ext, auto_cpp_level(self.compiler))
# Python 2 doesn't allow super here, since distutils uses old-style
# classes!
_build_ext.build_extensions(self)
def intree_extensions(paths, package_dir=None):
"""
Generate Pybind11Extensions from source files directly located in a Python
source tree.
``package_dir`` behaves as in ``setuptools.setup``. If unset, the Python
package root parent is determined as the first parent directory that does
not contain an ``__init__.py`` file.
"""
exts = []
for path in paths:
if package_dir is None:
parent, _ = os.path.split(path)
while os.path.exists(os.path.join(parent, "__init__.py")):
parent, _ = os.path.split(parent)
relname, _ = os.path.splitext(os.path.relpath(path, parent))
qualified_name = relname.replace(os.path.sep, ".")
exts.append(Pybind11Extension(qualified_name, [path]))
else:
found = False
for prefix, parent in package_dir.items():
if path.startswith(parent):
found = True
relname, _ = os.path.splitext(os.path.relpath(path, parent))
qualified_name = relname.replace(os.path.sep, ".")
if prefix:
qualified_name = prefix + "." + qualified_name
exts.append(Pybind11Extension(qualified_name, [path]))
if not found:
raise ValueError(
"path {} is not a child of any of the directories listed "
"in 'package_dir' ({})".format(path, package_dir)
)
return exts
def naive_recompile(obj, src):
"""
This will recompile only if the source file changes. It does not check
header files, so a more advanced function or Ccache is better if you have
editable header files in your package.
"""
return os.stat(obj).st_mtime < os.stat(src).st_mtime
def no_recompile(obg, src):
"""
This is the safest but slowest choice (and is the default) - will always
recompile sources.
"""
return True
# Optional parallel compile utility
# inspired by: http://stackoverflow.com/questions/11013851/speeding-up-build-process-with-distutils
# and: https://github.com/tbenthompson/cppimport/blob/stable/cppimport/build_module.py
# and NumPy's parallel distutils module:
# https://github.com/numpy/numpy/blob/master/numpy/distutils/ccompiler.py
class ParallelCompile(object):
"""
Make a parallel compile function. Inspired by
numpy.distutils.ccompiler.CCompiler_compile and cppimport.
This takes several arguments that allow you to customize the compile
function created:
envvar:
Set an environment variable to control the compilation threads, like
NPY_NUM_BUILD_JOBS
default:
0 will automatically multithread, or 1 will only multithread if the
envvar is set.
max:
The limit for automatic multithreading if non-zero
needs_recompile:
A function of (obj, src) that returns True when recompile is needed. No
effect in isolated mode; use ccache instead, see
https://github.com/matplotlib/matplotlib/issues/1507/
To use::
ParallelCompile("NPY_NUM_BUILD_JOBS").install()
or::
with ParallelCompile("NPY_NUM_BUILD_JOBS"):
setup(...)
By default, this assumes all files need to be recompiled. A smarter
function can be provided via needs_recompile. If the output has not yet
been generated, the compile will always run, and this function is not
called.
"""
__slots__ = ("envvar", "default", "max", "_old", "needs_recompile")
def __init__(self, envvar=None, default=0, max=0, needs_recompile=no_recompile):
self.envvar = envvar
self.default = default
self.max = max
self.needs_recompile = needs_recompile
self._old = []
def function(self):
"""
Builds a function object usable as distutils.ccompiler.CCompiler.compile.
"""
def compile_function(
compiler,
sources,
output_dir=None,
macros=None,
include_dirs=None,
debug=0,
extra_preargs=None,
extra_postargs=None,
depends=None,
):
# These lines are directly from distutils.ccompiler.CCompiler
macros, objects, extra_postargs, pp_opts, build = compiler._setup_compile(
output_dir, macros, include_dirs, sources, depends, extra_postargs
)
cc_args = compiler._get_cc_args(pp_opts, debug, extra_preargs)
# The number of threads; start with default.
threads = self.default
# Determine the number of compilation threads, unless set by an environment variable.
if self.envvar is not None:
threads = int(os.environ.get(self.envvar, self.default))
def _single_compile(obj):
try:
src, ext = build[obj]
except KeyError:
return
if not os.path.exists(obj) or self.needs_recompile(obj, src):
compiler._compile(obj, src, ext, cc_args, extra_postargs, pp_opts)
try:
# Importing .synchronize checks for platforms that have some multiprocessing
# capabilities but lack semaphores, such as AWS Lambda and Android Termux.
import multiprocessing.synchronize
from multiprocessing.pool import ThreadPool
except ImportError:
threads = 1
if threads == 0:
try:
threads = multiprocessing.cpu_count()
threads = self.max if self.max and self.max < threads else threads
except NotImplementedError:
threads = 1
if threads > 1:
for _ in ThreadPool(threads).imap_unordered(_single_compile, objects):
pass
else:
for ob in objects:
_single_compile(ob)
return objects
return compile_function
def install(self):
distutils.ccompiler.CCompiler.compile = self.function()
return self
def __enter__(self):
self._old.append(distutils.ccompiler.CCompiler.compile)
return self.install()
def __exit__(self, *args):
distutils.ccompiler.CCompiler.compile = self._old.pop()