ClangCL compiler support

Author: boberfly

distutils/_msvccompiler.py

@@ -5,6 +5,7 @@
 __all__ = ["MSVCCompiler"]
 
 MSVCCompiler = msvc.Compiler
+ClangCLCompiler = msvc.ClangCLCompiler
 
 
 def __getattr__(name):

distutils/compilers/C/base.py

@@ -1238,6 +1238,7 @@ def get_default_compiler(osname: str | None = None, platform: str | None = None)
     ),
     'bcpp': ('bcppcompiler', 'BCPPCompiler', "Borland C++ Compiler"),
     'zos': ('zosccompiler', 'zOSCCompiler', 'IBM XL C/C++ Compilers'),
+    'clangcl': ('_msvccompiler', 'ClangCLCompiler', 'LLVM Clang-CL compiler'),
 }
 
 

distutils/compilers/C/msvc.py

@@ -176,21 +176,37 @@ def _get_vc_env(plat_spec):
     return env
 
 
-def _find_exe(exe, paths=None):
+def _find_exe(exe, paths=None, clangcl=False):
     """Return path to an MSVC executable program.
 
     Tries to find the program in several places: first, one of the
     MSVC program search paths from the registry; next, the directories
     in the PATH environment variable.  If any of those work, return an
     absolute path that is known to exist.  If none of them work, just
     return the original program name, 'exe'.
+
+    If clangcl is set to true, look for the LLVM clang-cl executables,
+    as well as look for them without the extension (eg. on Linux)
     """
+    if clangcl:
+        if exe == 'cl.exe':
+            exe = 'clang-{}'.format(exe)
+        elif exe == 'link.exe':
+            exe = 'lld-{}'.format(exe)
+        elif exe == 'mc.exe':
+            exe = 'llvm-ml.exe'
+        else:
+            exe = 'llvm-{}'.format(exe)
     if not paths:
         paths = os.getenv('path').split(os.pathsep)
     for p in paths:
         fn = os.path.join(os.path.abspath(p), exe)
         if os.path.isfile(fn):
             return fn
+        elif clangcl:
+            fn = os.path.splitext(fn)[0]
+            if os.path.isfile(fn):
+                return fn
     return exe
 
 
@@ -201,6 +217,32 @@ def _find_exe(exe, paths=None):
     'win-arm64': 'arm64',
 }
 
+_clang_targets = {
+    'win32': 'i686',
+    'win-amd64': 'x86_64',
+    'win-arm32': 'armv7',
+    'win-arm64': 'aarch64',
+}
+
+
+def _get_external_sdk(linker=False):
+    sdk = []
+    vctoolsdir = os.environ.get('DISTUTILS_VCTOOLS_DIR', None)
+    winsdkdir = os.environ.get('DISTUTILS_WINSDK_DIR', None)
+    if vctoolsdir:
+        _vctoolsdir = ['/vctoolsdir', vctoolsdir]
+        if linker:
+            sdk.append(":".join(_vctoolsdir))
+        else:
+            sdk += _vctoolsdir
+    if winsdkdir:
+        _winsdkdir = ['/winsdkdir', winsdkdir]
+        if linker:
+            sdk.append(":".join(_winsdkdir))
+        else:
+            sdk += _winsdkdir
+    return sdk
+
 
 def _get_vcvars_spec(host_platform, platform):
     """
@@ -298,14 +340,16 @@ def initialize(self, plat_name: str | None = None) -> None:
             )
         self._configure(vc_env)
 
+        clangcl = True if self.compiler_type == "clangcl" else False
+
         self._paths = vc_env.get('path', '')
         paths = self._paths.split(os.pathsep)
-        self.cc = _find_exe("cl.exe", paths)
-        self.linker = _find_exe("link.exe", paths)
-        self.lib = _find_exe("lib.exe", paths)
-        self.rc = _find_exe("rc.exe", paths)  # resource compiler
-        self.mc = _find_exe("mc.exe", paths)  # message compiler
-        self.mt = _find_exe("mt.exe", paths)  # message compiler
+        self.cc = _find_exe("cl.exe", paths, clangcl)
+        self.linker = _find_exe("link.exe", paths, clangcl)
+        self.lib = _find_exe("lib.exe", paths, clangcl)
+        self.rc = _find_exe("rc.exe", paths, clangcl)  # resource compiler
+        self.mc = _find_exe("mc.exe", paths, clangcl)  # message compiler
+        self.mt = _find_exe("mt.exe", paths, clangcl)  # message compiler
 
         self.preprocess_options = None
         # bpo-38597: Always compile with dynamic linking
@@ -326,6 +370,16 @@ def initialize(self, plat_name: str | None = None) -> None:
 
         ldflags_debug = ['/nologo', '/INCREMENTAL:NO', '/LTCG', '/DEBUG:FULL']
 
+        if clangcl:
+            target = '--target={}-windows-msvc'.format(_clang_targets[plat_name])
+            compile_sdk = _get_external_sdk()
+            self.compile_options.remove('/GL')
+            self.compile_options += ['/FA', target] + compile_sdk
+            self.compile_options_debug += ['/FA', target] + compile_sdk
+            linker_sdk = _get_external_sdk(linker=True)
+            ldflags += linker_sdk
+            ldflags_debug += linker_sdk
+
         self.ldflags_exe = [*ldflags, '/MANIFEST:EMBED,ID=1']
         self.ldflags_exe_debug = [*ldflags_debug, '/MANIFEST:EMBED,ID=1']
         self.ldflags_shared = [
@@ -437,7 +491,11 @@ def compile(  # noqa: C901
                 rc_dir = os.path.dirname(obj)
                 try:
                     # first compile .MC to .RC and .H file
-                    self.spawn([self.mc, '-h', h_dir, '-r', rc_dir, src])
+                    mc_cmd = [self.mc]
+                    if clangcl and '64' in plat_name:
+                        mc_cmd.append('--m64')
+                    mc_cmd += ['-h', h_dir, '-r', rc_dir, src]
+                    self.spawn(mc_cmd)
                     base, _ = os.path.splitext(os.path.basename(src))
                     rc_file = os.path.join(rc_dir, base + '.rc')
                     # then compile .RC to .RES file
@@ -612,3 +670,8 @@ def find_library_file(self, dirs, lib, debug=False):
         else:
             # Oops, didn't find it in *any* of 'dirs'
             return None
+
+
+class ClangCLCompiler(Compiler):
+
+    compiler_type = 'clangcl'

distutils/compilers/C/tests/test_clangcl.py

@@ -0,0 +1,26 @@
+import os
+from .. import msvc
+
+
+class TestClangCLCompiler:
+    def test_compiler_type(self):
+        compiler = msvc.ClangCLCompiler()
+        assert compiler.compiler_type == 'clangcl'
+
+    def test_set_executables(self):
+        compiler = msvc.ClangCLCompiler()
+        compiler.initialize()
+
+        cc, cc_ext = os.path.splitext(compiler.cc)
+        linker, linker_ext = os.path.splitext(compiler.linker)
+        lib, lib_ext = os.path.splitext(compiler.lib)
+        rc, rc_ext = os.path.splitext(compiler.rc)
+        mc, mc_ext = os.path.splitext(compiler.mc)
+        mt, mt_ext = os.path.splitext(compiler.mt)
+
+        assert compiler.cc == 'clang-cl' + cc_ext
+        assert compiler.linker == 'lld-link' + linker_ext
+        assert compiler.lib == 'llvm-lib' + lib_ext
+        assert compiler.rc == 'llvm-rc' + rc_ext
+        assert compiler.mc == 'llvm-ml' + mc_ext
+        assert compiler.mt == 'llvm-mt' + mt_ext

distutils/tests/__init__.py

@@ -24,12 +24,12 @@ def missing_compiler_executable(cmd_names: Sequence[str] = []):  # pragma: no co
 
     compiler = ccompiler.new_compiler()
     sysconfig.customize_compiler(compiler)
-    if compiler.compiler_type == "msvc":
+    if compiler.compiler_type == "msvc" or compiler.compiler_type == "clangcl":
         # MSVC has no executables, so check whether initialization succeeds
         try:
             compiler.initialize()
         except errors.DistutilsPlatformError:
-            return "msvc"
+            return compiler.compiler_type
     for name in compiler.executables:
         if cmd_names and name not in cmd_names:
             continue

newsfragments/376.feature.rst

@@ -0,0 +1,3 @@
+Added ClangCL compiler support.
+Added DISTUTILS_VCTOOLS_DIR environment variable to set a specific vctools directory to ClangCL
+Added DISTUTILS_WINSDK_DIR environment variable to set a specific winsdk directory to ClangCL