unixccompiler.py

"""distutils.unixccompiler

Contains the UnixCCompiler class, a subclass of CCompiler that handles
the "typical" Unix-style command-line C compiler:
  * macros defined with -Dname[=value]
  * macros undefined with -Uname
  * include search directories specified with -Idir
  * libraries specified with -lllib
  * library search directories specified with -Ldir
  * compile handled by 'cc' (or similar) executable with -c option:
    compiles .c to .o
  * link static library handled by 'ar' command (possibly with 'ranlib')
  * link shared library handled by 'cc -shared'
"""

import os, sys, re, shlex

from distutils import sysconfig
from distutils.dep_util import newer
from distutils.ccompiler import \
     CCompiler, gen_preprocess_options, gen_lib_options
from distutils.errors import \
     DistutilsExecError, CompileError, LibError, LinkError
from distutils import log
from ._macos_compat import compiler_fixup

# XXX Things not currently handled:
#   * optimization/debug/warning flags; we just use whatever's in Python's
#     Makefile and live with it.  Is this adequate?  If not, we might
#     have to have a bunch of subclasses GNUCCompiler, SGICCompiler,
#     SunCCompiler, and I suspect down that road lies madness.
#   * even if we don't know a warning flag from an optimization flag,
#     we need some way for outsiders to feed preprocessor/compiler/linker
#     flags in to us -- eg. a sysadmin might want to mandate certain flags
#     via a site config file, or a user might want to set something for
#     compiling this module distribution only via the setup.py command
#     line, whatever.  As long as these options come from something on the
#     current system, they can be as system-dependent as they like, and we
#     should just happily stuff them into the preprocessor/compiler/linker
#     options and carry on.


def _split_env(cmd):
    """
    For macOS, split command into 'env' portion (if any)
    and the rest of the linker command.

    >>> _split_env(['a', 'b', 'c'])
    ([], ['a', 'b', 'c'])
    >>> _split_env(['/usr/bin/env', 'A=3', 'gcc'])
    (['/usr/bin/env', 'A=3'], ['gcc'])
    """
    pivot = 0
    if os.path.basename(cmd[0]) == "env":
        pivot = 1
        while '=' in cmd[pivot]:
            pivot += 1
    return cmd[:pivot], cmd[pivot:]


def _split_aix(cmd):
    """
    AIX platforms prefix the compiler with the ld_so_aix
    script, so split that from the linker command.

    >>> _split_aix(['a', 'b', 'c'])
    ([], ['a', 'b', 'c'])
    >>> _split_aix(['/bin/foo/ld_so_aix', 'gcc'])
    (['/bin/foo/ld_so_aix'], ['gcc'])
    """
    pivot = os.path.basename(cmd[0]) == 'ld_so_aix'
    return cmd[:pivot], cmd[pivot:]


def _linker_params(linker_cmd, compiler_cmd):
    """
    The linker command usually begins with the compiler
    command (possibly multiple elements), followed by zero or more
    params for shared library building.

    If the LDSHARED env variable overrides the linker command,
    however, the commands may not match.

    Return the best guess of the linker parameters by stripping
    the linker command. If the compiler command does not
    match the linker command, assume the linker command is
    just the first element.

    >>> _linker_params('gcc foo bar'.split(), ['gcc'])
    ['foo', 'bar']
    >>> _linker_params('gcc foo bar'.split(), ['other'])
    ['foo', 'bar']
    >>> _linker_params('ccache gcc foo bar'.split(), 'ccache gcc'.split())
    ['foo', 'bar']
    >>> _linker_params(['gcc'], ['gcc'])
    []
    """
    c_len = len(compiler_cmd)
    pivot = c_len if linker_cmd[:c_len] == compiler_cmd else 1
    return linker_cmd[pivot:]


class UnixCCompiler(CCompiler):

    compiler_type = 'unix'

    # These are used by CCompiler in two places: the constructor sets
    # instance attributes 'preprocessor', 'compiler', etc. from them, and
    # 'set_executable()' allows any of these to be set.  The defaults here
    # are pretty generic; they will probably have to be set by an outsider
    # (eg. using information discovered by the sysconfig about building
    # Python extensions).
    executables = {'preprocessor' : None,
                   'compiler'     : ["cc"],
                   'compiler_so'  : ["cc"],
                   'compiler_cxx' : ["cc"],
                   'linker_so'    : ["cc", "-shared"],
                   'linker_exe'   : ["cc"],
                   'archiver'     : ["ar", "-cr"],
                   'ranlib'       : None,
                  }

    if sys.platform[:6] == "darwin":
        executables['ranlib'] = ["ranlib"]

    # Needed for the filename generation methods provided by the base
    # class, CCompiler.  NB. whoever instantiates/uses a particular
    # UnixCCompiler instance should set 'shared_lib_ext' -- we set a
    # reasonable common default here, but it's not necessarily used on all
    # Unices!

    src_extensions = [".c",".C",".cc",".cxx",".cpp",".m"]
    obj_extension = ".o"
    static_lib_extension = ".a"
    shared_lib_extension = ".so"
    dylib_lib_extension = ".dylib"
    xcode_stub_lib_extension = ".tbd"
    static_lib_format = shared_lib_format = dylib_lib_format = "lib%s%s"
    xcode_stub_lib_format = dylib_lib_format
    if sys.platform == "cygwin":
        exe_extension = ".exe"

    def preprocess(self, source, output_file=None, macros=None,
                   include_dirs=None, extra_preargs=None, extra_postargs=None):
        fixed_args = self._fix_compile_args(None, macros, include_dirs)
        ignore, macros, include_dirs = fixed_args
        pp_opts = gen_preprocess_options(macros, include_dirs)
        pp_args = self.preprocessor + pp_opts
        if output_file:
            pp_args.extend(['-o', output_file])
        if extra_preargs:
            pp_args[:0] = extra_preargs
        if extra_postargs:
            pp_args.extend(extra_postargs)
        pp_args.append(source)

        # We need to preprocess: either we're being forced to, or we're
        # generating output to stdout, or there's a target output file and
        # the source file is newer than the target (or the target doesn't
        # exist).
        if self.force or output_file is None or newer(source, output_file):
            if output_file:
                self.mkpath(os.path.dirname(output_file))
            try:
                self.spawn(pp_args)
            except DistutilsExecError as msg:
                raise CompileError(msg)

    def _compile(self, obj, src, ext, cc_args, extra_postargs, pp_opts):
        compiler_so = compiler_fixup(
            self.compiler_so, cc_args + extra_postargs)
        try:
            self.spawn(compiler_so + cc_args + [src, '-o', obj] +
                       extra_postargs)
        except DistutilsExecError as msg:
            raise CompileError(msg)

    def create_static_lib(self, objects, output_libname,
                          output_dir=None, debug=0, target_lang=None):
        objects, output_dir = self._fix_object_args(objects, output_dir)

        output_filename = \
            self.library_filename(output_libname, output_dir=output_dir)

        if self._need_link(objects, output_filename):
            self.mkpath(os.path.dirname(output_filename))
            self.spawn(self.archiver +
                       [output_filename] +
                       objects + self.objects)

            # Not many Unices required ranlib anymore -- SunOS 4.x is, I
            # think the only major Unix that does.  Maybe we need some
            # platform intelligence here to skip ranlib if it's not
            # needed -- or maybe Python's configure script took care of
            # it for us, hence the check for leading colon.
            if self.ranlib:
                try:
                    self.spawn(self.ranlib + [output_filename])
                except DistutilsExecError as msg:
                    raise LibError(msg)
        else:
            log.debug("skipping %s (up-to-date)", output_filename)

    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):
        objects, output_dir = self._fix_object_args(objects, output_dir)
        fixed_args = self._fix_lib_args(libraries, library_dirs,
                                        runtime_library_dirs)
        libraries, library_dirs, runtime_library_dirs = fixed_args

        lib_opts = gen_lib_options(self, library_dirs, runtime_library_dirs,
                                   libraries)
        if not isinstance(output_dir, (str, type(None))):
            raise TypeError("'output_dir' must be a string or None")
        if output_dir is not None:
            output_filename = os.path.join(output_dir, output_filename)

        if self._need_link(objects, output_filename):
            ld_args = (objects + self.objects +
                       lib_opts + ['-o', output_filename])
            if debug:
                ld_args[:0] = ['-g']
            if extra_preargs:
                ld_args[:0] = extra_preargs
            if extra_postargs:
                ld_args.extend(extra_postargs)
            self.mkpath(os.path.dirname(output_filename))
            try:
                # Select a linker based on context: linker_exe when
                # building an executable or linker_so (with shared options)
                # when building a shared library.
                building_exe = target_desc == CCompiler.EXECUTABLE
                linker = (self.linker_exe if building_exe else self.linker_so)[:]

                if target_lang == "c++" and self.compiler_cxx:
                    env, linker_ne = _split_env(linker)
                    aix, linker_na = _split_aix(linker_ne)
                    _, compiler_cxx_ne = _split_env(self.compiler_cxx)
                    _, linker_exe_ne = _split_env(self.linker_exe)

                    params = _linker_params(linker_na, linker_exe_ne)
                    linker = env + aix + compiler_cxx_ne + params

                linker = compiler_fixup(linker, ld_args)

                self.spawn(linker + ld_args)
            except DistutilsExecError as msg:
                raise LinkError(msg)
        else:
            log.debug("skipping %s (up-to-date)", output_filename)

    # -- Miscellaneous methods -----------------------------------------
    # These are all used by the 'gen_lib_options() function, in
    # ccompiler.py.

    def library_dir_option(self, dir):
        return "-L" + dir

    def _is_gcc(self, compiler_name):
        return "gcc" in compiler_name or "g++" in compiler_name

    def runtime_library_dir_option(self, dir):
        # XXX Hackish, at the very least.  See Python bug #445902:
        # http://sourceforge.net/tracker/index.php
        #   ?func=detail&aid=445902&group_id=5470&atid=105470
        # Linkers on different platforms need different options to
        # specify that directories need to be added to the list of
        # directories searched for dependencies when a dynamic library
        # is sought.  GCC on GNU systems (Linux, FreeBSD, ...) has to
        # be told to pass the -R option through to the linker, whereas
        # other compilers and gcc on other systems just know this.
        # Other compilers may need something slightly different.  At
        # this time, there's no way to determine this information from
        # the configuration data stored in the Python installation, so
        # we use this hack.
        compiler = os.path.basename(shlex.split(sysconfig.get_config_var("CC"))[0])
        if sys.platform[:6] == "darwin":
            from distutils.util import get_macosx_target_ver, split_version
            macosx_target_ver = get_macosx_target_ver()
            if macosx_target_ver and split_version(macosx_target_ver) >= [10, 5]:
                return "-Wl,-rpath," + dir
            else: # no support for -rpath on earlier macOS versions
                return "-L" + dir
        elif sys.platform[:7] == "freebsd":
            return "-Wl,-rpath=" + dir
        elif sys.platform[:5] == "hp-ux":
            if self._is_gcc(compiler):
                return ["-Wl,+s", "-L" + dir]
            return ["+s", "-L" + dir]

        # For all compilers, `-Wl` is the presumed way to
        # pass a compiler option to the linker and `-R` is
        # the way to pass an RPATH.
        if sysconfig.get_config_var("GNULD") == "yes":
            # GNU ld needs an extra option to get a RUNPATH
            # instead of just an RPATH.
            return "-Wl,--enable-new-dtags,-R" + dir
        else:
            return "-Wl,-R" + dir

    def library_option(self, lib):
        return "-l" + lib

    def find_library_file(self, dirs, lib, debug=0):
        shared_f = self.library_filename(lib, lib_type='shared')
        dylib_f = self.library_filename(lib, lib_type='dylib')
        xcode_stub_f = self.library_filename(lib, lib_type='xcode_stub')
        static_f = self.library_filename(lib, lib_type='static')

        if sys.platform == 'darwin':
            # On OSX users can specify an alternate SDK using
            # '-isysroot', calculate the SDK root if it is specified
            # (and use it further on)
            #
            # Note that, as of Xcode 7, Apple SDKs may contain textual stub
            # libraries with .tbd extensions rather than the normal .dylib
            # shared libraries installed in /.  The Apple compiler tool
            # chain handles this transparently but it can cause problems
            # for programs that are being built with an SDK and searching
            # for specific libraries.  Callers of find_library_file need to
            # keep in mind that the base filename of the returned SDK library
            # file might have a different extension from that of the library
            # file installed on the running system, for example:
            #   /Applications/Xcode.app/Contents/Developer/Platforms/
            #       MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/
            #       usr/lib/libedit.tbd
            # vs
            #   /usr/lib/libedit.dylib
            cflags = sysconfig.get_config_var('CFLAGS')
            m = re.search(r'-isysroot\s*(\S+)', cflags)
            if m is None:
                sysroot = '/'
            else:
                sysroot = m.group(1)



        for dir in dirs:
            shared = os.path.join(dir, shared_f)
            dylib = os.path.join(dir, dylib_f)
            static = os.path.join(dir, static_f)
            xcode_stub = os.path.join(dir, xcode_stub_f)

            if sys.platform == 'darwin' and (
                dir.startswith('/System/') or (
                dir.startswith('/usr/') and not dir.startswith('/usr/local/'))):

                shared = os.path.join(sysroot, dir[1:], shared_f)
                dylib = os.path.join(sysroot, dir[1:], dylib_f)
                static = os.path.join(sysroot, dir[1:], static_f)
                xcode_stub = os.path.join(sysroot, dir[1:], xcode_stub_f)

            # We're second-guessing the linker here, with not much hard
            # data to go on: GCC seems to prefer the shared library, so I'm
            # assuming that *all* Unix C compilers do.  And of course I'm
            # ignoring even GCC's "-static" option.  So sue me.
            if os.path.exists(dylib):
                return dylib
            elif os.path.exists(xcode_stub):
                return xcode_stub
            elif os.path.exists(shared):
                return shared
            elif os.path.exists(static):
                return static

        # Oops, didn't find it in *any* of 'dirs'
        return None