compilers: don't use instance checks to determine properties

In various situations we want to figure out what type of compiler we
have, because we want to know stuff like "is it the pgi one", or "does
it use msvc style". The compiler object has this property already, via
an API specifically designed to communicate this info, but instead we
performed isinstance checks on a compiler class.

This is confusing and indirect, and has the side effect of requiring
more imports everywhere. We should do away with it.

mesonbuild/backend/ninjabackend.py

@@ -36,13 +36,8 @@ from .. import build
 from .. import mlog
 from .. import compilers
 from ..arglist import CompilerArgs
-from ..compilers import (
-    Compiler, CCompiler,
-    FortranCompiler,
-    mixins,
-    PGICCompiler,
-    VisualStudioLikeCompiler,
-)
+from ..compilers import Compiler
+from ..compilers.c import CCompiler
 from ..linkers import ArLinker, AppleArLinker, RSPFileSyntax
 from ..mesonlib import (
     File, LibType, MachineChoice, MesonException, OrderedSet, PerMachine,
@@ -60,6 +55,7 @@ if T.TYPE_CHECKING:
     from ..interpreter import Interpreter
     from ..linkers import DynamicLinker, StaticLinker
     from ..compilers.cs import CsCompiler
+    from ..compilers.fortran import FortranCompiler
 
     RUST_EDITIONS = Literal['2015', '2018', '2021']
 
@@ -516,12 +512,12 @@ class NinjaBackend(backends.Backend):
             # Have to detect the dependency format
 
             # IFort on windows is MSVC like, but doesn't have /showincludes
-            if isinstance(compiler, FortranCompiler):
+            if compiler.language == 'fortran':
                 continue
-            if isinstance(compiler, PGICCompiler) and mesonlib.is_windows():
+            if compiler.id == 'pgi' and mesonlib.is_windows():
                 # for the purpose of this function, PGI doesn't act enough like MSVC
                 return open(tempfilename, 'a', encoding='utf-8')
-            if isinstance(compiler, VisualStudioLikeCompiler):
+            if compiler.get_argument_syntax() == 'msvc':
                 break
         else:
             # None of our compilers are MSVC, we're done.
@@ -2325,7 +2321,7 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47485'''))
         command = compiler.get_exelist()
         args = ['$ARGS'] + depargs + NinjaCommandArg.list(compiler.get_output_args('$out'), Quoting.none) + compiler.get_compile_only_args() + ['$in']
         description = f'Compiling {compiler.get_display_language()} object $out'
-        if isinstance(compiler, VisualStudioLikeCompiler):
+        if compiler.get_argument_syntax() == 'msvc':
             deps = 'msvc'
             depfile = None
         else:
@@ -2341,13 +2337,13 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47485'''))
         rule = self.compiler_to_pch_rule_name(compiler)
         depargs = compiler.get_dependency_gen_args('$out', '$DEPFILE')
 
-        if isinstance(compiler, VisualStudioLikeCompiler):
+        if compiler.get_argument_syntax() == 'msvc':
             output = []
         else:
             output = NinjaCommandArg.list(compiler.get_output_args('$out'), Quoting.none)
         command = compiler.get_exelist() + ['$ARGS'] + depargs + output + compiler.get_compile_only_args() + ['$in']
         description = 'Precompiling header $in'
-        if isinstance(compiler, VisualStudioLikeCompiler):
+        if compiler.get_argument_syntax() == 'msvc':
             deps = 'msvc'
             depfile = None
         else:
@@ -2931,8 +2927,8 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47485'''))
                 msg = f'Precompiled header of {target.get_basename()!r} must not be in the same ' \
                       'directory as source, please put it in a subdirectory.'
                 raise InvalidArguments(msg)
-            compiler = target.compilers[lang]
-            if isinstance(compiler, VisualStudioLikeCompiler):
+            compiler: Compiler = target.compilers[lang]
+            if compiler.get_argument_syntax() == 'msvc':
                 (commands, dep, dst, objs, src) = self.generate_msvc_pch_command(target, compiler, pch)
                 extradep = os.path.join(self.build_to_src, target.get_source_subdir(), pch[0])
             elif compiler.id == 'intel':
@@ -3026,7 +3022,7 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47485'''))
 
     def get_link_whole_args(self, linker, target):
         use_custom = False
-        if isinstance(linker, mixins.visualstudio.MSVCCompiler):
+        if linker.id == 'msvc':
             # Expand our object lists manually if we are on pre-Visual Studio 2015 Update 2
             # (incidentally, the "linker" here actually refers to cl.exe)
             if mesonlib.version_compare(linker.version, '<19.00.23918'):

mesonbuild/cmake/toolchain.py

@@ -16,7 +16,6 @@ from __future__ import annotations
 from pathlib import Path
 from .traceparser import CMakeTraceParser
 from ..envconfig import CMakeSkipCompilerTest
-from ..compilers import VisualStudioLikeCompiler
 from .common import language_map, cmake_get_generator_args
 from .. import mlog
 
@@ -204,7 +203,7 @@ class CMakeToolchain:
 
     @staticmethod
     def is_cmdline_option(compiler: 'Compiler', arg: str) -> bool:
-        if isinstance(compiler, VisualStudioLikeCompiler):
+        if compiler.get_argument_syntax() == 'msvc':
             return arg.startswith('/')
         else:
             return arg.startswith('-')

mesonbuild/environment.py

@@ -845,10 +845,10 @@ class Environment:
 
     def get_compiler_system_dirs(self, for_machine: MachineChoice):
         for comp in self.coredata.compilers[for_machine].values():
-            if isinstance(comp, compilers.ClangCompiler):
+            if comp.id == 'clang':
                 index = 1
                 break
-            elif isinstance(comp, compilers.GnuCompiler):
+            elif comp.id == 'gcc':
                 index = 2
                 break
         else:

unittests/windowstests.py

@@ -32,7 +32,6 @@ from mesonbuild.mesonlib import (
 )
 from mesonbuild.compilers import (
     detect_c_compiler, detect_d_compiler, compiler_from_language,
-    GnuLikeCompiler
 )
 from mesonbuild.programs import ExternalProgram
 import mesonbuild.dependencies.base
@@ -222,21 +221,21 @@ class WindowsTests(BasePlatformTests):
     def test_link_environment_variable_lld_link(self):
         env = get_fake_env()
         comp = detect_c_compiler(env, MachineChoice.HOST)
-        if isinstance(comp, GnuLikeCompiler):
+        if comp.get_argument_syntax() == 'gcc':
             raise SkipTest('GCC cannot be used with link compatible linkers.')
         self._check_ld('lld-link', 'c', 'lld-link')
 
     def test_link_environment_variable_link(self):
         env = get_fake_env()
         comp = detect_c_compiler(env, MachineChoice.HOST)
-        if isinstance(comp, GnuLikeCompiler):
+        if comp.get_argument_syntax() == 'gcc':
             raise SkipTest('GCC cannot be used with link compatible linkers.')
         self._check_ld('link', 'c', 'link')
 
     def test_link_environment_variable_optlink(self):
         env = get_fake_env()
         comp = detect_c_compiler(env, MachineChoice.HOST)
-        if isinstance(comp, GnuLikeCompiler):
+        if comp.get_argument_syntax() == 'gcc':
             raise SkipTest('GCC cannot be used with link compatible linkers.')
         self._check_ld('optlink', 'c', 'optlink')