compilers: force clang{,-cl} to error on unknown warning options

gcc will error by default if an unknown warning option is passed to it:

    CC=gcc meson setup build -Dc_args=-Wbad

gcc will fail in the project() call during the sanity check. clang does
not currently doing that:

    CC=clang meson setup build -Dc_args=-Wbad
    ...will continue until an actual compilation like cc.compiles()

    from meson-log.txt...
    Sanity check compile stderr:
    warning: unknown warning option '-Wbad' [-Wunknown-warning-option]

We should error in the sanity check to notify the user as soon as
possible that they have errors in their environment.

Signed-off-by: Tristan Partin <tristan@partin.io>
Part-of: mesonbuild#15714
Closes: mesonbuild#15714
Signed-off-by: Sam James <sam@gentoo.org>

Author: tristan957

mesonbuild/compilers/compilers.py

@@ -1449,7 +1449,12 @@ def _sanity_check_compile_args(self, sourcename: str, binname: str
             OptionKey(f'{self.language}_args', machine=self.for_machine))))
         largs = list(T.cast('T.List[str]', optstore.get_value_for(
             OptionKey(f'{self.language}_link_args', machine=self.for_machine))))
-        return self.exelist_no_ccache + self.get_always_args() + self.get_output_args(binname) + [sourcename] + cargs, largs
+        return self.exelist_no_ccache \
+            + self.get_always_args() \
+            + self.get_compiler_check_args(CompileCheckMode.COMPILE) \
+            + self.get_output_args(binname) \
+            + [sourcename] \
+            + cargs, largs
 
     @abc.abstractmethod
     def _sanity_check_source_code(self) -> str:

mesonbuild/compilers/cpp.py

@@ -975,6 +975,10 @@ def get_cpp_modules_args(self) -> T.List[str]:
         # clang-cl does not support /interface.
         return ['-fmodules', '-fmodules-ts']
 
+    def get_compiler_check_args(self, mode: CompileCheckMode) -> T.List[str]:
+        # XXX: this is a hack because so much GnuLike stuff is in the base CPPCompiler class.
+        return ClangClCompiler.get_compiler_check_args(self, mode)
+
 
 class IntelClCPPCompiler(VisualStudioLikeCPPCompilerMixin, IntelVisualStudioLikeCompiler, CPPCompiler):
 

mesonbuild/compilers/mixins/visualstudio.py

@@ -469,14 +469,16 @@ def sanitizer_compile_args(self, target: T.Optional[BuildTarget], value: T.List[
             args.append('/clang:-fno-omit-frame-pointer')
         return args
 
-    def has_arguments(self, args: T.List[str], code: str, mode: CompileCheckMode) -> T.Tuple[bool, bool]:
+    def get_compiler_check_args(self, mode: CompileCheckMode) -> T.List[str]:
+        myargs: T.List[str] = []
         if mode != CompileCheckMode.LINK:
-            args = args + [
+            myargs.extend((
                 '-Werror=unknown-argument',
                 '-Werror=unknown-warning-option',
                 '-Werror=unused-command-line-argument',
-            ]
-        return super().has_arguments(args, code, mode)
+            ))
+
+        return super().get_compiler_check_args(mode) + myargs
 
     def get_pch_base_name(self, header: str) -> str:
         return header

unittests/internaltests.py

@@ -29,8 +29,9 @@
 import mesonbuild.scripts.depfixer
 import mesonbuild.scripts.env2mfile
 from mesonbuild import coredata
-from mesonbuild.compilers.c import ClangCCompiler, GnuCCompiler
-from mesonbuild.compilers.compilers import Compiler, ManyInOneLinkerOptionStyle
+from mesonbuild.compilers import Compiler
+from mesonbuild.compilers.c import ClangCCompiler, ClangClCCompiler, GnuCCompiler
+from mesonbuild.compilers.compilers import CompileCheckMode, ManyInOneLinkerOptionStyle
 from mesonbuild.compilers.cpp import VisualStudioCPPCompiler
 from mesonbuild.compilers.d import DmdDCompiler
 from mesonbuild.compilers.detect import detect_c_compiler
@@ -435,6 +436,27 @@ def test_clike_sanity_check_drops_link_only_args_when_compile_only(self):
         self.assertEqual(largs, [])
 
 
+    def test_clang_family_compiler_check_args_contain_werror_unknown_warning(self):
+        env = get_fake_env()
+        mold = linkers.MoldDynamicLinker([], env, MachineChoice.HOST, '-Wl,', [])
+        lld_link = linkers.ClangClDynamicLinker(env, MachineChoice.HOST, [])
+
+        compilers = {
+            'clang': ClangCCompiler([], [], '14.0.0', MachineChoice.HOST, env, linker=mold),
+            'clang-cl': ClangClCCompiler([], '14.0.0', MachineChoice.HOST, env, 'x64', linker=lld_link),
+        }
+
+        for name, cc in compilers.items():
+            with self.subTest(compiler=name):
+                self.assertIn('-Werror=unknown-warning-option',
+                              cc.get_compiler_check_args(CompileCheckMode.COMPILE))
+                # Both clang and clang-cl only apply this diagnostic when
+                # actually compiling; it's intentionally omitted for LINK to
+                # avoid failing on flags that are unused during linking.
+                self.assertNotIn('-Werror=unknown-warning-option',
+                                 cc.get_compiler_check_args(CompileCheckMode.LINK))
+
+
     def test_msvc_unix_args_to_native(self):
         # joined
         self.assertEqual(MSVCCompiler.unix_args_to_native(['-isystemfoo']), ['/Ifoo'])

unittests/linuxliketests.py

@@ -845,8 +845,13 @@ def test_cpp_std_override(self):
         self.assertNotIn('-std=c++98', plain_comp)
         self.assertNotIn('-std=c++11', plain_comp)
         # Now werror
-        self.assertIn('-Werror', plain_comp)
-        self.assertNotIn('-Werror', c98_comp)
+        self.assertIn('-Werror', plain_comp.split())
+        self.assertNotIn('-Werror', c98_comp.split())
+
+    def test_sanity_check_fails_on_bad_c_args(self):
+        testdir = os.path.join(self.common_test_dir, '1 trivial')
+        with self.assertRaises((subprocess.CalledProcessError, RuntimeError)):
+            self.init(testdir, extra_args=['-Dc_args=-Wbad-flag-does-not-exist'])
 
     def test_run_installed(self):
         if is_cygwin() or is_osx():