cygwinccompiler.py

"""distutils.cygwinccompiler

Provides the CygwinCCompiler class, a subclass of UnixCCompiler that
handles the Cygwin port of the GNU C compiler to Windows.  It also contains
the Mingw32CCompiler class which handles the mingw32 port of GCC (same as
cygwin in no-cygwin mode).
"""

import os
import sys
import copy
import shlex
import warnings
from subprocess import check_output

from distutils.unixccompiler import UnixCCompiler
from distutils.file_util import write_file
from distutils.errors import (
    DistutilsExecError,
    DistutilsPlatformError,
    CCompilerError,
    CompileError,
)
from distutils.version import LooseVersion, suppress_known_deprecation


def get_msvcr():
    """Include the appropriate MSVC runtime library if Python was built
    with MSVC 7.0 or later.
    """
    msc_pos = sys.version.find('MSC v.')
    if msc_pos != -1:
        msc_ver = sys.version[msc_pos + 6 : msc_pos + 10]
        if msc_ver == '1300':
            # MSVC 7.0
            return ['msvcr70']
        elif msc_ver == '1310':
            # MSVC 7.1
            return ['msvcr71']
        elif msc_ver == '1400':
            # VS2005 / MSVC 8.0
            return ['msvcr80']
        elif msc_ver == '1500':
            # VS2008 / MSVC 9.0
            return ['msvcr90']
        elif msc_ver == '1600':
            # VS2010 / MSVC 10.0
            return ['msvcr100']
        elif msc_ver == '1700':
            # VS2012 / MSVC 11.0
            return ['msvcr110']
        elif msc_ver == '1800':
            # VS2013 / MSVC 12.0
            return ['msvcr120']
        elif 1900 <= int(msc_ver) < 2000:
            # VS2015 / MSVC 14.0
            return ['ucrt', 'vcruntime140']
        else:
            raise ValueError("Unknown MS Compiler version %s " % msc_ver)


_runtime_library_dirs_msg = (
    "Unable to set runtime library search path on Windows, "
    "usually indicated by `runtime_library_dirs` parameter to Extension"
)


class CygwinCCompiler(UnixCCompiler):
    """Handles the Cygwin port of the GNU C compiler to Windows."""

    compiler_type = 'cygwin'
    obj_extension = ".o"
    static_lib_extension = ".a"
    shared_lib_extension = ".dll.a"
    dylib_lib_extension = ".dll"
    static_lib_format = "lib%s%s"
    shared_lib_format = "lib%s%s"
    dylib_lib_format = "cyg%s%s"
    exe_extension = ".exe"

    def __init__(self, verbose=0, dry_run=0, force=0):

        super().__init__(verbose, dry_run, force)

        status, details = check_config_h()
        self.debug_print(
            "Python's GCC status: {} (details: {})".format(status, details)
        )
        if status is not CONFIG_H_OK:
            self.warn(
                "Python's pyconfig.h doesn't seem to support your compiler. "
                "Reason: %s. "
                "Compiling may fail because of undefined preprocessor macros." % details
            )

        self.cc = os.environ.get('CC', 'gcc')
        self.cxx = os.environ.get('CXX', 'g++')

        self.linker_dll = self.cc
        shared_option = "-shared"

        self.set_executables(
            compiler='%s -mcygwin -O -Wall' % self.cc,
            compiler_so='%s -mcygwin -mdll -O -Wall' % self.cc,
            compiler_cxx='%s -mcygwin -O -Wall' % self.cxx,
            linker_exe='%s -mcygwin' % self.cc,
            linker_so=('{} -mcygwin {}'.format(self.linker_dll, shared_option)),
        )

        # Include the appropriate MSVC runtime library if Python was built
        # with MSVC 7.0 or later.
        self.dll_libraries = get_msvcr()

    @property
    def gcc_version(self):
        # Older numpy dependend on this existing to check for ancient
        # gcc versions. This doesn't make much sense with clang etc so
        # just hardcode to something recent.
        # https://github.com/numpy/numpy/pull/20333
        warnings.warn(
            "gcc_version attribute of CygwinCCompiler is deprecated. "
            "Instead of returning actual gcc version a fixed value 11.2.0 is returned.",
            DeprecationWarning,
            stacklevel=2,
        )
        with suppress_known_deprecation():
            return LooseVersion("11.2.0")

    def _compile(self, obj, src, ext, cc_args, extra_postargs, pp_opts):
        """Compiles the source by spawning GCC and windres if needed."""
        if ext == '.rc' or ext == '.res':
            # gcc needs '.res' and '.rc' compiled to object files !!!
            try:
                self.spawn(["windres", "-i", src, "-o", obj])
            except DistutilsExecError as msg:
                raise CompileError(msg)
        else:  # for other files use the C-compiler
            try:
                self.spawn(
                    self.compiler_so + cc_args + [src, '-o', obj] + extra_postargs
                )
            except DistutilsExecError as msg:
                raise CompileError(msg)

    def link(
        self,
        target_desc,
        objects,
        output_filename,
        output_dir=None,
        libraries=None,
        library_dirs=None,
        runtime_library_dirs=None,
        export_symbols=None,
        debug=0,
        extra_preargs=None,
        extra_postargs=None,
        build_temp=None,
        target_lang=None,
    ):
        """Link the objects."""
        # use separate copies, so we can modify the lists
        extra_preargs = copy.copy(extra_preargs or [])
        libraries = copy.copy(libraries or [])
        objects = copy.copy(objects or [])

        if runtime_library_dirs:
            self.warn(_runtime_library_dirs_msg)

        # Additional libraries
        libraries.extend(self.dll_libraries)

        # handle export symbols by creating a def-file
        # with executables this only works with gcc/ld as linker
        if (export_symbols is not None) and (
            target_desc != self.EXECUTABLE or self.linker_dll == "gcc"
        ):
            # (The linker doesn't do anything if output is up-to-date.
            # So it would probably better to check if we really need this,
            # but for this we had to insert some unchanged parts of
            # UnixCCompiler, and this is not what we want.)

            # we want to put some files in the same directory as the
            # object files are, build_temp doesn't help much
            # where are the object files
            temp_dir = os.path.dirname(objects[0])
            # name of dll to give the helper files the same base name
            (dll_name, dll_extension) = os.path.splitext(
                os.path.basename(output_filename)
            )

            # generate the filenames for these files
            def_file = os.path.join(temp_dir, dll_name + ".def")

            # Generate .def file
            contents = ["LIBRARY %s" % os.path.basename(output_filename), "EXPORTS"]
            for sym in export_symbols:
                contents.append(sym)
            self.execute(write_file, (def_file, contents), "writing %s" % def_file)

            # next add options for def-file

            # for gcc/ld the def-file is specified as any object files
            objects.append(def_file)

        # end: if ((export_symbols is not None) and
        #        (target_desc != self.EXECUTABLE or self.linker_dll == "gcc")):

        # who wants symbols and a many times larger output file
        # should explicitly switch the debug mode on
        # otherwise we let ld strip the output file
        # (On my machine: 10KiB < stripped_file < ??100KiB
        #   unstripped_file = stripped_file + XXX KiB
        #  ( XXX=254 for a typical python extension))
        if not debug:
            extra_preargs.append("-s")

        UnixCCompiler.link(
            self,
            target_desc,
            objects,
            output_filename,
            output_dir,
            libraries,
            library_dirs,
            runtime_library_dirs,
            None,  # export_symbols, we do this in our def-file
            debug,
            extra_preargs,
            extra_postargs,
            build_temp,
            target_lang,
        )

    def runtime_library_dir_option(self, dir):
        # cygwin doesn't support rpath. While in theory we could error
        # out like MSVC does, code might expect it to work like on Unix, so
        # just warn and hope for the best.
        self.warn(_runtime_library_dirs_msg)
        return []

    # -- Miscellaneous methods -----------------------------------------

    def _make_out_path(self, output_dir, strip_dir, src_name):
        # use normcase to make sure '.rc' is really '.rc' and not '.RC'
        norm_src_name = os.path.normcase(src_name)
        return super()._make_out_path(output_dir, strip_dir, norm_src_name)

    @property
    def out_extensions(self):
        """
        Add support for rc and res files.
        """
        return {
            **super().out_extensions,
            **{ext: ext + self.obj_extension for ext in ('.res', '.rc')},
        }


# the same as cygwin plus some additional parameters
class Mingw32CCompiler(CygwinCCompiler):
    """Handles the Mingw32 port of the GNU C compiler to Windows."""

    compiler_type = 'mingw32'

    def __init__(self, verbose=0, dry_run=0, force=0):

        super().__init__(verbose, dry_run, force)

        shared_option = "-shared"

        if is_cygwincc(self.cc):
            raise CCompilerError('Cygwin gcc cannot be used with --compiler=mingw32')

        self.set_executables(
            compiler='%s -O -Wall' % self.cc,
            compiler_so='%s -mdll -O -Wall' % self.cc,
            compiler_cxx='%s -O -Wall' % self.cxx,
            linker_exe='%s' % self.cc,
            linker_so='{} {}'.format(self.linker_dll, shared_option),
        )

        # Maybe we should also append -mthreads, but then the finished
        # dlls need another dll (mingwm10.dll see Mingw32 docs)
        # (-mthreads: Support thread-safe exception handling on `Mingw32')

        # no additional libraries needed
        self.dll_libraries = []

        # Include the appropriate MSVC runtime library if Python was built
        # with MSVC 7.0 or later.
        self.dll_libraries = get_msvcr()

    def runtime_library_dir_option(self, dir):
        raise DistutilsPlatformError(_runtime_library_dirs_msg)


# Because these compilers aren't configured in Python's pyconfig.h file by
# default, we should at least warn the user if he is using an unmodified
# version.

CONFIG_H_OK = "ok"
CONFIG_H_NOTOK = "not ok"
CONFIG_H_UNCERTAIN = "uncertain"


def check_config_h():
    """Check if the current Python installation appears amenable to building
    extensions with GCC.

    Returns a tuple (status, details), where 'status' is one of the following
    constants:

    - CONFIG_H_OK: all is well, go ahead and compile
    - CONFIG_H_NOTOK: doesn't look good
    - CONFIG_H_UNCERTAIN: not sure -- unable to read pyconfig.h

    'details' is a human-readable string explaining the situation.

    Note there are two ways to conclude "OK": either 'sys.version' contains
    the string "GCC" (implying that this Python was built with GCC), or the
    installed "pyconfig.h" contains the string "__GNUC__".
    """

    # XXX since this function also checks sys.version, it's not strictly a
    # "pyconfig.h" check -- should probably be renamed...

    from distutils import sysconfig

    # if sys.version contains GCC then python was compiled with GCC, and the
    # pyconfig.h file should be OK
    if "GCC" in sys.version:
        return CONFIG_H_OK, "sys.version mentions 'GCC'"

    # Clang would also work
    if "Clang" in sys.version:
        return CONFIG_H_OK, "sys.version mentions 'Clang'"

    # let's see if __GNUC__ is mentioned in python.h
    fn = sysconfig.get_config_h_filename()
    try:
        config_h = open(fn)
        try:
            if "__GNUC__" in config_h.read():
                return CONFIG_H_OK, "'%s' mentions '__GNUC__'" % fn
            else:
                return CONFIG_H_NOTOK, "'%s' does not mention '__GNUC__'" % fn
        finally:
            config_h.close()
    except OSError as exc:
        return (CONFIG_H_UNCERTAIN, "couldn't read '{}': {}".format(fn, exc.strerror))


def is_cygwincc(cc):
    '''Try to determine if the compiler that would be used is from cygwin.'''
    out_string = check_output(shlex.split(cc) + ['-dumpmachine'])
    return out_string.strip().endswith(b'cygwin')


get_versions = None
"""
A stand-in for the previous get_versions() function to prevent failures
when monkeypatched. See pypa/setuptools#2969.
"""