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).
"""

# problems:
#
# * if you use a msvc compiled python version (1.5.2)
#   1. you have to insert a __GNUC__ section in its config.h
#   2. you have to generate an import library for its dll
#      - create a def-file for python??.dll
#      - create an import library using
#             dlltool --dllname python15.dll --def python15.def \
#                       --output-lib libpython15.a
#
#   see also http://starship.python.net/crew/kernr/mingw32/Notes.html
#
# * We put export_symbols in a def-file, and don't use
#   --export-all-symbols because it doesn't worked reliable in some
#   tested configurations. And because other windows compilers also
#   need their symbols specified this no serious problem.
#
# tested configurations:
#
# * cygwin gcc 2.91.57/ld 2.9.4/dllwrap 0.2.4 works
#   (after patching python's config.h and for C++ some other include files)
#   see also http://starship.python.net/crew/kernr/mingw32/Notes.html
# * mingw32 gcc 2.95.2/ld 2.9.4/dllwrap 0.2.4 works
#   (ld doesn't support -shared, so we use dllwrap)
# * cygwin gcc 2.95.2/ld 2.10.90/dllwrap 2.10.90 works now
#   - its dllwrap doesn't work, there is a bug in binutils 2.10.90
#     see also http://sources.redhat.com/ml/cygwin/2000-06/msg01274.html
#   - using gcc -mdll instead dllwrap doesn't work without -static because
#     it tries to link against dlls instead their import libraries. (If
#     it finds the dll first.)
#     By specifying -static we force ld to link against the import libraries,
#     this is windows standard and there are normally not the necessary symbols
#     in the dlls.
#   *** only the version of June 2000 shows these problems
# * cygwin gcc 3.2/ld 2.13.90 works
#   (ld supports -shared)
# * mingw gcc 3.2/ld 2.13 works
#   (ld supports -shared)

import sys
from subprocess import Popen, PIPE, check_output
import re

from distutils.unixccompiler import UnixCCompiler
from distutils.errors import CCompilerError
from distutils.version import LooseVersion
from distutils.spawn import find_executable

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']
        else:
            raise ValueError("Unknown MS Compiler version %s " % msc_ver)


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"
    static_lib_format = "lib%s%s"
    shared_lib_format = "%s%s"
    exe_extension = ".exe"

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

        UnixCCompiler.__init__(self, verbose, dry_run, force)

        status, details = check_config_h()
        self.debug_print("Python's GCC status: %s (details: %s)" %
                         (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.gcc_version, self.ld_version, self.dllwrap_version = \
            get_versions()
        self.debug_print(self.compiler_type + ": gcc %s, ld %s, dllwrap %s\n" %
                         (self.gcc_version,
                          self.ld_version,
                          self.dllwrap_version) )

        # ld_version >= "2.10.90" and < "2.13" should also be able to use
        # gcc -mdll instead of dllwrap
        # Older dllwraps had own version numbers, newer ones use the
        # same as the rest of binutils ( also ld )
        # dllwrap 2.10.90 is buggy
        if self.ld_version >= "2.10.90":
            self.linker_dll = "gcc"
        else:
            self.linker_dll = "dllwrap"

        # ld_version >= "2.13" support -shared so use it instead of
        # -mdll -static
        if self.ld_version >= "2.13":
            shared_option = "-shared"
        else:
            shared_option = "-mdll -static"

        # Hard-code GCC because that's what this is all about.
        # XXX optimization, warnings etc. should be customizable.
        self.set_executables(compiler='gcc -mcygwin -O -Wall',
                             compiler_so='gcc -mcygwin -mdll -O -Wall',
                             compiler_cxx='g++ -mcygwin -O -Wall',
                             linker_exe='gcc -mcygwin',
                             linker_so=('%s -mcygwin %s' %
                                        (self.linker_dll, shared_option)))

        # cygwin and mingw32 need different sets of libraries
        if self.gcc_version == "2.91.57":
            # cygwin shouldn't need msvcrt, but without the dlls will crash
            # (gcc version 2.91.57) -- perhaps something about initialization
            self.dll_libraries=["msvcrt"]
            self.warn(
                "Consider upgrading to a newer version of gcc")
        else:
            # Include the appropriate MSVC runtime library if Python was built
            # with MSVC 7.0 or later.
            self.dll_libraries = get_msvcr()


# 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):

        CygwinCCompiler.__init__ (self, verbose, dry_run, force)

        # ld_version >= "2.13" support -shared so use it instead of
        # -mdll -static
        if self.ld_version >= "2.13":
            shared_option = "-shared"
        else:
            shared_option = "-mdll -static"

        # A real mingw32 doesn't need to specify a different entry point,
        # but cygwin 2.91.57 in no-cygwin-mode needs it.
        if self.gcc_version <= "2.91.57":
            entry_point = '--entry _DllMain@12'
        else:
            entry_point = ''

        if is_cygwingcc():
            raise CCompilerError(
                'Cygwin gcc cannot be used with --compiler=mingw32')

        self.set_executables(compiler='gcc -O -Wall',
                             compiler_so='gcc -mdll -O -Wall',
                             compiler_cxx='g++ -O -Wall',
                             linker_exe='gcc',
                             linker_so='%s %s %s'
                                        % (self.linker_dll, shared_option,
                                           entry_point))
        # 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()

# 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...

    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'"

    # 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 '%s': %s" % (fn, exc.strerror))

RE_VERSION = re.compile(br'(\d+\.\d+(\.\d+)*)')

def _find_exe_version(cmd):
    """Find the version of an executable by running `cmd` in the shell.

    If the command is not found, or the output does not match
    `RE_VERSION`, returns None.
    """
    executable = cmd.split()[0]
    if find_executable(executable) is None:
        return None
    out = Popen(cmd, shell=True, stdout=PIPE).stdout
    try:
        out_string = out.read()
    finally:
        out.close()
    result = RE_VERSION.search(out_string)
    if result is None:
        return None
    # LooseVersion works with strings
    # so we need to decode our bytes
    return LooseVersion(result.group(1).decode())

def get_versions():
    """ Try to find out the versions of gcc, ld and dllwrap.

    If not possible it returns None for it.
    """
    commands = ['gcc -dumpversion', 'ld -v', 'dllwrap --version']
    return tuple([_find_exe_version(cmd) for cmd in commands])

def is_cygwingcc():
    '''Try to determine if the gcc that would be used is from cygwin.'''
    out_string = check_output(['gcc', '-dumpmachine'])
    return out_string.strip().endswith(b'cygwin')