Issue #15184: Ensure consistent results of OS X configuration
tailoring for universal builds by factoring out common OS X-specific
customizations from sysconfig, distutils.sysconfig, distutils.util,
and distutils.unixccompiler into a new module _osx_support that can
eventually also be used by packaging.
diff --git a/Lib/_osx_support.py b/Lib/_osx_support.py
new file mode 100644
index 0000000..b3aad56
--- /dev/null
+++ b/Lib/_osx_support.py
@@ -0,0 +1,488 @@
+"""Shared OS X support functions."""
+
+import os
+import re
+import sys
+
+__all__ = [
+ 'compiler_fixup',
+ 'customize_config_vars',
+ 'customize_compiler',
+ 'get_platform_osx',
+]
+
+# configuration variables that may contain universal build flags,
+# like "-arch" or "-isdkroot", that may need customization for
+# the user environment
+_UNIVERSAL_CONFIG_VARS = ('CFLAGS', 'LDFLAGS', 'CPPFLAGS', 'BASECFLAGS',
+ 'BLDSHARED', 'LDSHARED', 'CC', 'CXX',
+ 'PY_CFLAGS', 'PY_LDFLAGS', 'PY_CPPFLAGS',
+ 'PY_CORE_CFLAGS')
+
+# configuration variables that may contain compiler calls
+_COMPILER_CONFIG_VARS = ('BLDSHARED', 'LDSHARED', 'CC', 'CXX')
+
+# prefix added to original configuration variable names
+_INITPRE = '_OSX_SUPPORT_INITIAL_'
+
+
+def _find_executable(executable, path=None):
+ """Tries to find 'executable' in the directories listed in 'path'.
+
+ A string listing directories separated by 'os.pathsep'; defaults to
+ os.environ['PATH']. Returns the complete filename or None if not found.
+ """
+ if path is None:
+ path = os.environ['PATH']
+
+ paths = path.split(os.pathsep)
+ base, ext = os.path.splitext(executable)
+
+ if (sys.platform == 'win32' or os.name == 'os2') and (ext != '.exe'):
+ executable = executable + '.exe'
+
+ if not os.path.isfile(executable):
+ for p in paths:
+ f = os.path.join(p, executable)
+ if os.path.isfile(f):
+ # the file exists, we have a shot at spawn working
+ return f
+ return None
+ else:
+ return executable
+
+
+def _read_output(commandstring):
+ """Output from succesful command execution or None"""
+ # Similar to os.popen(commandstring, "r").read(),
+ # but without actually using os.popen because that
+ # function is not usable during python bootstrap.
+ # tempfile is also not available then.
+ import contextlib
+ try:
+ import tempfile
+ fp = tempfile.NamedTemporaryFile()
+ except ImportError:
+ fp = open("/tmp/_osx_support.%s"%(
+ os.getpid(),), "w+b")
+
+ with contextlib.closing(fp) as fp:
+ cmd = "%s 2>/dev/null >'%s'" % (commandstring, fp.name)
+ return fp.read().decode('utf-8').strip() if not os.system(cmd) else None
+
+
+def _find_build_tool(toolname):
+ """Find a build tool on current path or using xcrun"""
+ return (_find_executable(toolname)
+ or _read_output("/usr/bin/xcrun -find %s" % (toolname,))
+ or ''
+ )
+
+_SYSTEM_VERSION = None
+
+def _get_system_version():
+ """Return the OS X system version as a string"""
+ # Reading this plist is a documented way to get the system
+ # version (see the documentation for the Gestalt Manager)
+ # We avoid using platform.mac_ver to avoid possible bootstrap issues during
+ # the build of Python itself (distutils is used to build standard library
+ # extensions).
+
+ global _SYSTEM_VERSION
+
+ if _SYSTEM_VERSION is None:
+ _SYSTEM_VERSION = ''
+ try:
+ f = open('/System/Library/CoreServices/SystemVersion.plist')
+ except IOError:
+ # We're on a plain darwin box, fall back to the default
+ # behaviour.
+ pass
+ else:
+ try:
+ m = re.search(r'<key>ProductUserVisibleVersion</key>\s*'
+ r'<string>(.*?)</string>', f.read())
+ finally:
+ f.close()
+ if m is not None:
+ _SYSTEM_VERSION = '.'.join(m.group(1).split('.')[:2])
+ # else: fall back to the default behaviour
+
+ return _SYSTEM_VERSION
+
+def _remove_original_values(_config_vars):
+ """Remove original unmodified values for testing"""
+ # This is needed for higher-level cross-platform tests of get_platform.
+ for k in list(_config_vars):
+ if k.startswith(_INITPRE):
+ del _config_vars[k]
+
+def _save_modified_value(_config_vars, cv, newvalue):
+ """Save modified and original unmodified value of configuration var"""
+
+ oldvalue = _config_vars.get(cv, '')
+ if (oldvalue != newvalue) and (_INITPRE + cv not in _config_vars):
+ _config_vars[_INITPRE + cv] = oldvalue
+ _config_vars[cv] = newvalue
+
+def _supports_universal_builds():
+ """Returns True if universal builds are supported on this system"""
+ # As an approximation, we assume that if we are running on 10.4 or above,
+ # then we are running with an Xcode environment that supports universal
+ # builds, in particular -isysroot and -arch arguments to the compiler. This
+ # is in support of allowing 10.4 universal builds to run on 10.3.x systems.
+
+ osx_version = _get_system_version()
+ if osx_version:
+ try:
+ osx_version = tuple(int(i) for i in osx_version.split('.'))
+ except ValueError:
+ osx_version = ''
+ return bool(osx_version >= (10, 4)) if osx_version else False
+
+
+def _find_appropriate_compiler(_config_vars):
+ """Find appropriate C compiler for extension module builds"""
+
+ # Issue #13590:
+ # The OSX location for the compiler varies between OSX
+ # (or rather Xcode) releases. With older releases (up-to 10.5)
+ # the compiler is in /usr/bin, with newer releases the compiler
+ # can only be found inside Xcode.app if the "Command Line Tools"
+ # are not installed.
+ #
+ # Futhermore, the compiler that can be used varies between
+ # Xcode releases. Upto Xcode 4 it was possible to use 'gcc-4.2'
+ # as the compiler, after that 'clang' should be used because
+ # gcc-4.2 is either not present, or a copy of 'llvm-gcc' that
+ # miscompiles Python.
+
+ # skip checks if the compiler was overriden with a CC env variable
+ if 'CC' in os.environ:
+ return _config_vars
+
+ # The CC config var might contain additional arguments.
+ # Ignore them while searching.
+ cc = oldcc = _config_vars['CC'].split()[0]
+ if not _find_executable(cc):
+ # Compiler is not found on the shell search PATH.
+ # Now search for clang, first on PATH (if the Command LIne
+ # Tools have been installed in / or if the user has provided
+ # another location via CC). If not found, try using xcrun
+ # to find an uninstalled clang (within a selected Xcode).
+
+ # NOTE: Cannot use subprocess here because of bootstrap
+ # issues when building Python itself (and os.popen is
+ # implemented on top of subprocess and is therefore not
+ # usable as well)
+
+ cc = _find_build_tool('clang')
+
+ elif os.path.basename(cc).startswith('gcc'):
+ # Compiler is GCC, check if it is LLVM-GCC
+ data = _read_output("'%s' --version"
+ % (cc.replace("'", "'\"'\"'"),))
+ if 'llvm-gcc' in data:
+ # Found LLVM-GCC, fall back to clang
+ cc = _find_build_tool('clang')
+
+ if not cc:
+ raise SystemError(
+ "Cannot locate working compiler")
+
+ if cc != oldcc:
+ # Found a replacement compiler.
+ # Modify config vars using new compiler, if not already explictly
+ # overriden by an env variable, preserving additional arguments.
+ for cv in _COMPILER_CONFIG_VARS:
+ if cv in _config_vars and cv not in os.environ:
+ cv_split = _config_vars[cv].split()
+ cv_split[0] = cc if cv != 'CXX' else cc + '++'
+ _save_modified_value(_config_vars, cv, ' '.join(cv_split))
+
+ return _config_vars
+
+
+def _remove_universal_flags(_config_vars):
+ """Remove all universal build arguments from config vars"""
+
+ for cv in _UNIVERSAL_CONFIG_VARS:
+ # Do not alter a config var explicitly overriden by env var
+ if cv in _config_vars and cv not in os.environ:
+ flags = _config_vars[cv]
+ flags = re.sub('-arch\s+\w+\s', ' ', flags, re.ASCII)
+ flags = re.sub('-isysroot [^ \t]*', ' ', flags)
+ _save_modified_value(_config_vars, cv, flags)
+
+ return _config_vars
+
+
+def _remove_unsupported_archs(_config_vars):
+ """Remove any unsupported archs from config vars"""
+ # Different Xcode releases support different sets for '-arch'
+ # flags. In particular, Xcode 4.x no longer supports the
+ # PPC architectures.
+ #
+ # This code automatically removes '-arch ppc' and '-arch ppc64'
+ # when these are not supported. That makes it possible to
+ # build extensions on OSX 10.7 and later with the prebuilt
+ # 32-bit installer on the python.org website.
+
+ # skip checks if the compiler was overriden with a CC env variable
+ if 'CC' in os.environ:
+ return _config_vars
+
+ if re.search('-arch\s+ppc', _config_vars['CFLAGS']) is not None:
+ # NOTE: Cannot use subprocess here because of bootstrap
+ # issues when building Python itself
+ status = os.system("'%s' -arch ppc -x c /dev/null 2>/dev/null"%(
+ _config_vars['CC'].replace("'", "'\"'\"'"),))
+ # The Apple compiler drivers return status 255 if no PPC
+ if (status >> 8) == 255:
+ # Compiler doesn't support PPC, remove the related
+ # '-arch' flags if not explicitly overridden by an
+ # environment variable
+ for cv in _UNIVERSAL_CONFIG_VARS:
+ if cv in _config_vars and cv not in os.environ:
+ flags = _config_vars[cv]
+ flags = re.sub('-arch\s+ppc\w*\s', ' ', flags)
+ _save_modified_value(_config_vars, cv, flags)
+
+ return _config_vars
+
+
+def _override_all_archs(_config_vars):
+ """Allow override of all archs with ARCHFLAGS env var"""
+ # NOTE: This name was introduced by Apple in OSX 10.5 and
+ # is used by several scripting languages distributed with
+ # that OS release.
+ if 'ARCHFLAGS' in os.environ:
+ arch = os.environ['ARCHFLAGS']
+ for cv in _UNIVERSAL_CONFIG_VARS:
+ if cv in _config_vars and '-arch' in _config_vars[cv]:
+ flags = _config_vars[cv]
+ flags = re.sub('-arch\s+\w+\s', ' ', flags)
+ flags = flags + ' ' + arch
+ _save_modified_value(_config_vars, cv, flags)
+
+ return _config_vars
+
+
+def _check_for_unavailable_sdk(_config_vars):
+ """Remove references to any SDKs not available"""
+ # If we're on OSX 10.5 or later and the user tries to
+ # compile an extension using an SDK that is not present
+ # on the current machine it is better to not use an SDK
+ # than to fail. This is particularly important with
+ # the standalong Command Line Tools alternative to a
+ # full-blown Xcode install since the CLT packages do not
+ # provide SDKs. If the SDK is not present, it is assumed
+ # that the header files and dev libs have been installed
+ # to /usr and /System/Library by either a standalone CLT
+ # package or the CLT component within Xcode.
+ cflags = _config_vars.get('CFLAGS', '')
+ m = re.search(r'-isysroot\s+(\S+)', cflags)
+ if m is not None:
+ sdk = m.group(1)
+ if not os.path.exists(sdk):
+ for cv in _UNIVERSAL_CONFIG_VARS:
+ # Do not alter a config var explicitly overriden by env var
+ if cv in _config_vars and cv not in os.environ:
+ flags = _config_vars[cv]
+ flags = re.sub(r'-isysroot\s+\S+(?:\s|$)', ' ', flags)
+ _save_modified_value(_config_vars, cv, flags)
+
+ return _config_vars
+
+
+def compiler_fixup(compiler_so, cc_args):
+ """
+ This function will strip '-isysroot PATH' and '-arch ARCH' from the
+ compile flags if the user has specified one them in extra_compile_flags.
+
+ This is needed because '-arch ARCH' adds another architecture to the
+ build, without a way to remove an architecture. Furthermore GCC will
+ barf if multiple '-isysroot' arguments are present.
+ """
+ stripArch = stripSysroot = False
+
+ compiler_so = list(compiler_so)
+
+ if not _supports_universal_builds():
+ # OSX before 10.4.0, these don't support -arch and -isysroot at
+ # all.
+ stripArch = stripSysroot = True
+ else:
+ stripArch = '-arch' in cc_args
+ stripSysroot = '-isysroot' in cc_args
+
+ if stripArch or 'ARCHFLAGS' in os.environ:
+ while True:
+ try:
+ index = compiler_so.index('-arch')
+ # Strip this argument and the next one:
+ del compiler_so[index:index+2]
+ except ValueError:
+ break
+
+ if 'ARCHFLAGS' in os.environ and not stripArch:
+ # User specified different -arch flags in the environ,
+ # see also distutils.sysconfig
+ compiler_so = compiler_so + os.environ['ARCHFLAGS'].split()
+
+ if stripSysroot:
+ while True:
+ try:
+ index = compiler_so.index('-isysroot')
+ # Strip this argument and the next one:
+ del compiler_so[index:index+2]
+ except ValueError:
+ break
+
+ # Check if the SDK that is used during compilation actually exists,
+ # the universal build requires the usage of a universal SDK and not all
+ # users have that installed by default.
+ sysroot = None
+ if '-isysroot' in cc_args:
+ idx = cc_args.index('-isysroot')
+ sysroot = cc_args[idx+1]
+ elif '-isysroot' in compiler_so:
+ idx = compiler_so.index('-isysroot')
+ sysroot = compiler_so[idx+1]
+
+ if sysroot and not os.path.isdir(sysroot):
+ from distutils import log
+ log.warn("Compiling with an SDK that doesn't seem to exist: %s",
+ sysroot)
+ log.warn("Please check your Xcode installation")
+
+ return compiler_so
+
+
+def customize_config_vars(_config_vars):
+ """Customize Python build configuration variables.
+
+ Called internally from sysconfig with a mutable mapping
+ containing name/value pairs parsed from the configured
+ makefile used to build this interpreter. Returns
+ the mapping updated as needed to reflect the environment
+ in which the interpreter is running; in the case of
+ a Python from a binary installer, the installed
+ environment may be very different from the build
+ environment, i.e. different OS levels, different
+ built tools, different available CPU architectures.
+
+ This customization is performed whenever
+ distutils.sysconfig.get_config_vars() is first
+ called. It may be used in environments where no
+ compilers are present, i.e. when installing pure
+ Python dists. Customization of compiler paths
+ and detection of unavailable archs is deferred
+ until the first extention module build is
+ requested (in distutils.sysconfig.customize_compiler).
+
+ Currently called from distutils.sysconfig
+ """
+
+ if not _supports_universal_builds():
+ # On Mac OS X before 10.4, check if -arch and -isysroot
+ # are in CFLAGS or LDFLAGS and remove them if they are.
+ # This is needed when building extensions on a 10.3 system
+ # using a universal build of python.
+ _remove_universal_flags(_config_vars)
+
+ # Allow user to override all archs with ARCHFLAGS env var
+ _override_all_archs(_config_vars)
+
+ # Remove references to sdks that are not found
+ _check_for_unavailable_sdk(_config_vars)
+
+ return _config_vars
+
+
+def customize_compiler(_config_vars):
+ """Customize compiler path and configuration variables.
+
+ This customization is performed when the first
+ extension module build is requested
+ in distutils.sysconfig.customize_compiler).
+ """
+
+ # Find a compiler to use for extension module builds
+ _find_appropriate_compiler(_config_vars)
+
+ # Remove ppc arch flags if not supported here
+ _remove_unsupported_archs(_config_vars)
+
+ # Allow user to override all archs with ARCHFLAGS env var
+ _override_all_archs(_config_vars)
+
+ return _config_vars
+
+
+def get_platform_osx(_config_vars, osname, release, machine):
+ """Filter values for get_platform()"""
+ # called from get_platform() in sysconfig and distutils.util
+ #
+ # For our purposes, we'll assume that the system version from
+ # distutils' perspective is what MACOSX_DEPLOYMENT_TARGET is set
+ # to. This makes the compatibility story a bit more sane because the
+ # machine is going to compile and link as if it were
+ # MACOSX_DEPLOYMENT_TARGET.
+
+ macver = _config_vars.get('MACOSX_DEPLOYMENT_TARGET', '')
+ macrelease = _get_system_version() or macver
+ macver = macver or macrelease
+
+ if macver:
+ release = macver
+ osname = "macosx"
+
+ # Use the original CFLAGS value, if available, so that we
+ # return the same machine type for the platform string.
+ # Otherwise, distutils may consider this a cross-compiling
+ # case and disallow installs.
+ cflags = _config_vars.get(_INITPRE+'CFLAGS',
+ _config_vars.get('CFLAGS', ''))
+ if ((macrelease + '.') >= '10.4.' and
+ '-arch' in cflags.strip()):
+ # The universal build will build fat binaries, but not on
+ # systems before 10.4
+
+ machine = 'fat'
+
+ archs = re.findall('-arch\s+(\S+)', cflags)
+ archs = tuple(sorted(set(archs)))
+
+ if len(archs) == 1:
+ machine = archs[0]
+ elif archs == ('i386', 'ppc'):
+ machine = 'fat'
+ elif archs == ('i386', 'x86_64'):
+ machine = 'intel'
+ elif archs == ('i386', 'ppc', 'x86_64'):
+ machine = 'fat3'
+ elif archs == ('ppc64', 'x86_64'):
+ machine = 'fat64'
+ elif archs == ('i386', 'ppc', 'ppc64', 'x86_64'):
+ machine = 'universal'
+ else:
+ raise ValueError(
+ "Don't know machine value for archs=%r" % (archs,))
+
+ elif machine == 'i386':
+ # On OSX the machine type returned by uname is always the
+ # 32-bit variant, even if the executable architecture is
+ # the 64-bit variant
+ if sys.maxsize >= 2**32:
+ machine = 'x86_64'
+
+ elif machine in ('PowerPC', 'Power_Macintosh'):
+ # Pick a sane name for the PPC architecture.
+ # See 'i386' case
+ if sys.maxsize >= 2**32:
+ machine = 'ppc64'
+ else:
+ machine = 'ppc'
+
+ return (osname, release, machine)