compilers: Split C-Like functionality into a mixin classes

Currently C++ inherits C, which can lead to diamond problems. By pulling
the code out into a standalone mixin class that the C, C++, ObjC, and
Objc++ compilers can inherit and override as necessary we remove one
source of diamonding. I've chosen to split this out into it's own file
as the CLikeCompiler class is over 1000 lines by itself. This also
breaks the VisualStudio derived classes inheriting from each other, to
avoid the same C -> CPP inheritance problems. This is all one giant
patch because there just isn't a clean way to separate this.

I've done the same for Fortran since it effectively inherits the
CCompiler (I say effectively because was it actually did was gross
beyond explanation), it's probably not correct, but it seems to work for
now. There really is a lot of layering violation going on in the
Compilers, and a really good scrubbing would do this code a lot of good.

1 files changed, 329 insertions, 0 deletions

diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index 2f3c7b7..a3401e8 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -1529,6 +1529,335 @@ def gnulike_default_include_dirs(compiler, lang):
     return paths
 
 
+class VisualStudioLikeCompiler(metaclass=abc.ABCMeta):
+
+    """A common interface for all compilers implementing an MSVC-style
+    interface.
+
+    A number of compilers attempt to mimic MSVC, with varying levels of
+    success, such as Clang-CL and ICL (the Intel C/C++ Compiler for Windows).
+    This classs implements as much common logic as possible.
+    """
+
+    std_warn_args = ['/W3']
+    std_opt_args = ['/O2']
+    ignore_libs = unixy_compiler_internal_libs
+    internal_libs = ()
+
+    crt_args = {'none': [],
+                'md': ['/MD'],
+                'mdd': ['/MDd'],
+                'mt': ['/MT'],
+                'mtd': ['/MTd'],
+                }
+    # /showIncludes is needed for build dependency tracking in Ninja
+    # See: https://ninja-build.org/manual.html#_deps
+    always_args = ['/nologo', '/showIncludes']
+    warn_args = {'0': ['/W1'],
+                 '1': ['/W2'],
+                 '2': ['/W3'],
+                 '3': ['/W4'],
+                 }
+
+    def __init__(self, target: str):
+        self.base_options = ['b_pch', 'b_ndebug', 'b_vscrt'] # FIXME add lto, pgo and the like
+        self.target = target
+        self.is_64 = ('x64' in target) or ('x86_64' in target)
+        # do some canonicalization of target machine
+        if 'x86_64' in target:
+            self.machine = 'x64'
+        elif '86' in target:
+            self.machine = 'x86'
+        else:
+            self.machine = target
+
+    # Override CCompiler.get_always_args
+    def get_always_args(self):
+        return self.always_args
+
+    def get_linker_debug_crt_args(self):
+        """
+        Arguments needed to select a debug crt for the linker
+
+        Sometimes we need to manually select the CRT (C runtime) to use with
+        MSVC. One example is when trying to link with static libraries since
+        MSVC won't auto-select a CRT for us in that case and will error out
+        asking us to select one.
+        """
+        return ['/MDd']
+
+    def get_buildtype_args(self, buildtype):
+        args = msvc_buildtype_args[buildtype]
+        if self.id == 'msvc' and version_compare(self.version, '<18.0'):
+            args = [arg for arg in args if arg != '/Gw']
+        return args
+
+    def get_buildtype_linker_args(self, buildtype):
+        return msvc_buildtype_linker_args[buildtype]
+
+    def get_pch_suffix(self):
+        return 'pch'
+
+    def get_pch_name(self, header):
+        chopped = os.path.basename(header).split('.')[:-1]
+        chopped.append(self.get_pch_suffix())
+        pchname = '.'.join(chopped)
+        return pchname
+
+    def get_pch_use_args(self, pch_dir, header):
+        base = os.path.basename(header)
+        if self.id == 'clang-cl':
+            base = header
+        pchname = self.get_pch_name(header)
+        return ['/FI' + base, '/Yu' + base, '/Fp' + os.path.join(pch_dir, pchname)]
+
+    def get_preprocess_only_args(self):
+        return ['/EP']
+
+    def get_compile_only_args(self):
+        return ['/c']
+
+    def get_no_optimization_args(self):
+        return ['/Od']
+
+    def get_output_args(self, target):
+        if target.endswith('.exe'):
+            return ['/Fe' + target]
+        return ['/Fo' + target]
+
+    def get_optimization_args(self, optimization_level):
+        return msvc_optimization_args[optimization_level]
+
+    def get_debug_args(self, is_debug):
+        return msvc_debug_args[is_debug]
+
+    def get_dependency_gen_args(self, outtarget, outfile):
+        return []
+
+    def get_linker_exelist(self):
+        # FIXME, should have same path as compiler.
+        # FIXME, should be controllable via cross-file.
+        if self.id == 'clang-cl':
+            return ['lld-link']
+        else:
+            return ['link']
+
+    def get_linker_always_args(self):
+        return ['/nologo']
+
+    def get_linker_output_args(self, outputname):
+        return ['/MACHINE:' + self.machine, '/OUT:' + outputname]
+
+    def get_linker_search_args(self, dirname):
+        return ['/LIBPATH:' + dirname]
+
+    def linker_to_compiler_args(self, args):
+        return ['/link'] + args
+
+    def get_gui_app_args(self, value):
+        # the default is for the linker to guess the subsystem based on presence
+        # of main or WinMain symbols, so always be explicit
+        if value:
+            return ['/SUBSYSTEM:WINDOWS']
+        else:
+            return ['/SUBSYSTEM:CONSOLE']
+
+    def get_pic_args(self):
+        return [] # PIC is handled by the loader on Windows
+
+    def gen_export_dynamic_link_args(self, env):
+        return [] # Not applicable with MSVC
+
+    def get_std_shared_lib_link_args(self):
+        return ['/DLL']
+
+    def gen_vs_module_defs_args(self, defsfile):
+        if not isinstance(defsfile, str):
+            raise RuntimeError('Module definitions file should be str')
+        # With MSVC, DLLs only export symbols that are explicitly exported,
+        # so if a module defs file is specified, we use that to export symbols
+        return ['/DEF:' + defsfile]
+
+    def gen_pch_args(self, header, source, pchname):
+        objname = os.path.splitext(pchname)[0] + '.obj'
+        return objname, ['/Yc' + header, '/Fp' + pchname, '/Fo' + objname]
+
+    def gen_import_library_args(self, implibname):
+        "The name of the outputted import library"
+        return ['/IMPLIB:' + implibname]
+
+    def build_rpath_args(self, build_dir, from_dir, rpath_paths, build_rpath, install_rpath):
+        return []
+
+    def openmp_flags(self):
+        return ['/openmp']
+
+    # FIXME, no idea what these should be.
+    def thread_flags(self, env):
+        return []
+
+    def thread_link_flags(self, env):
+        return []
+
+    @classmethod
+    def unix_args_to_native(cls, args):
+        result = []
+        for i in args:
+            # -mms-bitfields is specific to MinGW-GCC
+            # -pthread is only valid for GCC
+            if i in ('-mms-bitfields', '-pthread'):
+                continue
+            if i.startswith('-L'):
+                i = '/LIBPATH:' + i[2:]
+            # Translate GNU-style -lfoo library name to the import library
+            elif i.startswith('-l'):
+                name = i[2:]
+                if name in cls.ignore_libs:
+                    # With MSVC, these are provided by the C runtime which is
+                    # linked in by default
+                    continue
+                else:
+                    i = name + '.lib'
+            # -pthread in link flags is only used on Linux
+            elif i == '-pthread':
+                continue
+            result.append(i)
+        return result
+
+    def get_werror_args(self):
+        return ['/WX']
+
+    def get_include_args(self, path, is_system):
+        if path == '':
+            path = '.'
+        # msvc does not have a concept of system header dirs.
+        return ['-I' + path]
+
+    def compute_parameters_with_absolute_paths(self, parameter_list, build_dir):
+        for idx, i in enumerate(parameter_list):
+            if i[:2] == '-I' or i[:2] == '/I':
+                parameter_list[idx] = i[:2] + os.path.normpath(os.path.join(build_dir, i[2:]))
+            elif i[:9] == '/LIBPATH:':
+                parameter_list[idx] = i[:9] + os.path.normpath(os.path.join(build_dir, i[9:]))
+
+        return parameter_list
+
+    # Visual Studio is special. It ignores some arguments it does not
+    # understand and you can't tell it to error out on those.
+    # http://stackoverflow.com/questions/15259720/how-can-i-make-the-microsoft-c-compiler-treat-unknown-flags-as-errors-rather-t
+    def has_arguments(self, args, env, code, mode):
+        warning_text = '4044' if mode == 'link' else '9002'
+        if self.id == 'clang-cl' and mode != 'link':
+            args = args + ['-Werror=unknown-argument']
+        with self._build_wrapper(code, env, extra_args=args, mode=mode) as p:
+            if p.returncode != 0:
+                return False, p.cached
+            return not(warning_text in p.stde or warning_text in p.stdo), p.cached
+
+    def get_compile_debugfile_args(self, rel_obj, pch=False):
+        pdbarr = rel_obj.split('.')[:-1]
+        pdbarr += ['pdb']
+        args = ['/Fd' + '.'.join(pdbarr)]
+        # When generating a PDB file with PCH, all compile commands write
+        # to the same PDB file. Hence, we need to serialize the PDB
+        # writes using /FS since we do parallel builds. This slows down the
+        # build obviously, which is why we only do this when PCH is on.
+        # This was added in Visual Studio 2013 (MSVC 18.0). Before that it was
+        # always on: https://msdn.microsoft.com/en-us/library/dn502518.aspx
+        if pch and self.id == 'msvc' and version_compare(self.version, '>=18.0'):
+            args = ['/FS'] + args
+        return args
+
+    def get_link_debugfile_args(self, targetfile):
+        pdbarr = targetfile.split('.')[:-1]
+        pdbarr += ['pdb']
+        return ['/DEBUG', '/PDB:' + '.'.join(pdbarr)]
+
+    def get_link_whole_for(self, args):
+        # Only since VS2015
+        args = mesonlib.listify(args)
+        return ['/WHOLEARCHIVE:' + x for x in args]
+
+    def get_instruction_set_args(self, instruction_set):
+        if self.is_64:
+            return vs64_instruction_set_args.get(instruction_set, None)
+        if self.id == 'msvc' and self.version.split('.')[0] == '16' and instruction_set == 'avx':
+            # VS documentation says that this exists and should work, but
+            # it does not. The headers do not contain AVX intrinsics
+            # and the can not be called.
+            return None
+        return vs32_instruction_set_args.get(instruction_set, None)
+
+    def get_toolset_version(self):
+        if self.id == 'clang-cl':
+            # I have no idea
+            return '14.1'
+
+        # See boost/config/compiler/visualc.cpp for up to date mapping
+        try:
+            version = int(''.join(self.version.split('.')[0:2]))
+        except ValueError:
+            return None
+        if version < 1310:
+            return '7.0'
+        elif version < 1400:
+            return '7.1' # (Visual Studio 2003)
+        elif version < 1500:
+            return '8.0' # (Visual Studio 2005)
+        elif version < 1600:
+            return '9.0' # (Visual Studio 2008)
+        elif version < 1700:
+            return '10.0' # (Visual Studio 2010)
+        elif version < 1800:
+            return '11.0' # (Visual Studio 2012)
+        elif version < 1900:
+            return '12.0' # (Visual Studio 2013)
+        elif version < 1910:
+            return '14.0' # (Visual Studio 2015)
+        elif version < 1920:
+            return '14.1' # (Visual Studio 2017)
+        elif version < 1930:
+            return '14.2' # (Visual Studio 2019)
+        mlog.warning('Could not find toolset for version {!r}'.format(self.version))
+        return None
+
+    def get_default_include_dirs(self):
+        if 'INCLUDE' not in os.environ:
+            return []
+        return os.environ['INCLUDE'].split(os.pathsep)
+
+    def get_crt_compile_args(self, crt_val, buildtype):
+        if crt_val in self.crt_args:
+            return self.crt_args[crt_val]
+        assert(crt_val == 'from_buildtype')
+        # Match what build type flags used to do.
+        if buildtype == 'plain':
+            return []
+        elif buildtype == 'debug':
+            return self.crt_args['mdd']
+        elif buildtype == 'debugoptimized':
+            return self.crt_args['md']
+        elif buildtype == 'release':
+            return self.crt_args['md']
+        elif buildtype == 'minsize':
+            return self.crt_args['md']
+        else:
+            assert(buildtype == 'custom')
+            raise mesonlib.EnvironmentException('Requested C runtime based on buildtype, but buildtype is "custom".')
+
+    def has_func_attribute(self, name, env):
+        # MSVC doesn't have __attribute__ like Clang and GCC do, so just return
+        # false without compiling anything
+        return name in ['dllimport', 'dllexport'], False
+
+    def get_argument_syntax(self):
+        return 'msvc'
+
+    def get_allow_undefined_link_args(self):
+        # link.exe
+        return ['/FORCE:UNRESOLVED']
+
+
 class GnuLikeCompiler(abc.ABC):
     """
     GnuLikeCompiler is a common interface to all compilers implementing