Ensure detailed machine info for ASM compilers

mesonbuild/compilers/detect.py

@@ -8,7 +8,7 @@
     search_version, is_windows, Popen_safe, Popen_safe_logged, version_compare, windows_proof_rm,
 )
 from ..programs import ExternalProgram
-from ..envconfig import BinaryTable, detect_cpu_family, detect_machine_info
+from ..envconfig import BinaryTable, detect_cpu_family
 from .. import mlog
 
 from ..linkers import guess_win_linker, guess_nix_linker
@@ -1329,6 +1329,8 @@ def detect_nasm_compiler(env: 'Environment', for_machine: MachineChoice) -> Comp
 
     # We need a C compiler to properly detect the machine info and linker
     cc = detect_c_compiler(env, for_machine)
+    if not (env.build_machines_are_exact or env.is_cross_build(for_machine)):
+        env.update_build_machine({'c': cc})
 
     popen_exceptions: T.Dict[str, Exception] = {}
     for comp in compilers:
@@ -1368,10 +1370,10 @@ def detect_nasm_compiler(env: 'Environment', for_machine: MachineChoice) -> Comp
 def detect_masm_compiler(env: 'Environment', for_machine: MachineChoice) -> Compiler:
     # We need a C compiler to properly detect the machine info and linker
     cc = detect_c_compiler(env, for_machine)
-    if not env.is_cross_build(for_machine):
-        info = detect_machine_info({'c': cc})
-    else:
-        info = env.machines[for_machine]
+    if not (env.build_machines_are_exact or env.is_cross_build(for_machine)):
+        env.update_build_machine({'c': cc})
+
+    info = env.machines[for_machine]
 
     from .asm import MasmCompiler, MasmARMCompiler
     comp_class: T.Type[ASMCompiler]
@@ -1411,6 +1413,8 @@ def detect_linearasm_compiler(env: Environment, for_machine: MachineChoice) -> C
     comp_class: T.Type[ASMCompiler] = TILinearAsmCompiler
     arg = '-h'
     cc = detect_c_compiler(env, for_machine)
+    if not (env.build_machines_are_exact or env.is_cross_build(for_machine)):
+        env.update_build_machine({'c': cc})
 
     popen_exceptions: T.Dict[str, Exception] = {}
     try:

mesonbuild/environment.py

@@ -230,6 +230,8 @@ def __init__(self, source_dir: str, build_dir: T.Optional[str], cmd_options: cmd
         self.default_pkgconfig = ['pkg-config']
         self.wrap_resolver: T.Optional['Resolver'] = None
 
+        self.build_machines_are_exact = False
+
     def mfilestr2key(self, machine_file_string: str, section: T.Optional[str], section_subproject: T.Optional[str], machine: MachineChoice) -> OptionKey:
         key = OptionKey.from_string(machine_file_string)
         if key.subproject:
@@ -613,3 +615,20 @@ def add_lang_args(self, lang: str, comp: T.Type['Compiler'],
             # This is how autotools works, and the env vars feature is for
             # autotools compatibility.
             largs.extend_value(comp_options)
+
+    def update_build_machine(self, compilers: T.Optional[T.Dict[str, Compiler]] = None) -> None:
+        """Redetect the build machine and update the machine definitions
+
+        :compilers: An optional dictionary of compilers to use instead of the coredata dict.
+        """
+        if self.build_machines_are_exact:
+            return
+
+        compilers = compilers or self.coredata.compilers.build
+        if not compilers:
+            return
+
+        machines = self.machines.miss_defaulting()
+        machines.build = detect_machine_info(compilers)
+        self.machines = machines.default_missing()
+        self.build_machines_are_exact = True

mesonbuild/interpreter/interpreter.py

@@ -309,12 +309,7 @@ def _redetect_machines(self) -> None:
         # Re-initialize machine descriptions. We can do a better job now because we
         # have the compilers needed to gain more knowledge, so wipe out old
         # inference and start over.
-        machines = self.build.environment.machines.miss_defaulting()
-        machines.build = envconfig.detect_machine_info(self.coredata.compilers.build)
-        self.build.environment.machines = machines.default_missing()
-        assert self.build.environment.machines.build.cpu is not None
-        assert self.build.environment.machines.host.cpu is not None
-        assert self.build.environment.machines.target.cpu is not None
+        self.build.environment.update_build_machine()
 
         self.builtin['build_machine'] = \
             OBJ.MachineHolder(self.build.environment.machines.build, self)