Make compilers list per subproject

Previously subprojects inherited languages already added by main
project, or any previous subproject. This change to have a list of
compilers per interpreters, which means that if a subproject does not
add 'c' language  it won't be able to compile .c files any more, even if
main project added the 'c' language.

This delays processing list of compilers until the interpreter adds the
BuildTarget into its list of targets. That way the interpreter can add
missing languages instead of duplicating that logic into BuildTarget for
the cython case.

1 files changed, 19 insertions, 18 deletions

diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index 15d7d32..815737c 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -23,7 +23,8 @@ from .. import compilers
 from .. import envconfig
 from ..wrap import wrap, WrapMode
 from .. import mesonlib
-from ..mesonlib import MesonBugException, HoldableObject, FileMode, MachineChoice, OptionKey, listify, extract_as_list, has_path_sep
+from ..mesonlib import (MesonBugException, HoldableObject, FileMode, MachineChoice, OptionKey,
+                        listify, extract_as_list, has_path_sep, PerMachine)
 from ..programs import ExternalProgram, NonExistingExternalProgram
 from ..dependencies import Dependency
 from ..depfile import DepFile
@@ -304,6 +305,7 @@ class Interpreter(InterpreterBase, HoldableObject):
         self.build_func_dict()
         self.build_holder_map()
         self.user_defined_options = user_defined_options
+        self.compilers: PerMachine[T.Dict[str, 'Compiler']] = PerMachine({}, {})
 
         # build_def_files needs to be defined before parse_project is called
         #
@@ -1346,7 +1348,7 @@ external dependencies (including libraries) must go to "dependencies".''')
 
     def add_languages_for(self, args: T.List[str], required: bool, for_machine: MachineChoice) -> bool:
         args = [a.lower() for a in args]
-        langs = set(self.coredata.compilers[for_machine].keys())
+        langs = set(self.compilers[for_machine].keys())
         langs.update(args)
         # We'd really like to add cython's default language here, but it can't
         # actually be done because the cython compiler hasn't been initialized,
@@ -1360,11 +1362,11 @@ external dependencies (including libraries) must go to "dependencies".''')
 
         success = True
         for lang in sorted(args, key=compilers.sort_clink):
-            clist = self.coredata.compilers[for_machine]
+            if lang in self.compilers[for_machine]:
+                continue
             machine_name = for_machine.get_lower_case_name()
-            if lang in clist:
-                comp = clist[lang]
-            else:
+            comp = self.coredata.compilers[for_machine].get(lang)
+            if not comp:
                 try:
                     comp = compilers.detect_compiler_for(self.environment, lang, for_machine)
                     if comp is None:
@@ -1402,6 +1404,7 @@ external dependencies (including libraries) must go to "dependencies".''')
                 logger_fun(comp.get_display_language(), 'linker for the', machine_name, 'machine:',
                            mlog.bold(' '.join(comp.linker.get_exelist())), comp.linker.id, comp.linker.version)
             self.build.ensure_static_linker(comp)
+            self.compilers[for_machine][lang] = comp
 
         return success
 
@@ -2830,6 +2833,13 @@ Try setting b_lundef to false instead.'''.format(self.coredata.options[OptionKey
         idname = tobj.get_id()
         if idname in self.build.targets:
             raise InvalidCode(f'Tried to create target "{name}", but a target of that name already exists.')
+
+        if isinstance(tobj, build.BuildTarget):
+            missing_languages = tobj.process_compilers()
+            self.add_languages(missing_languages, True, tobj.for_machine)
+            tobj.process_compilers_late(missing_languages)
+            self.add_stdlib_info(tobj)
+
         self.build.targets[idname] = tobj
         if idname not in self.coredata.target_guids:
             self.coredata.target_guids[idname] = str(uuid.uuid4()).upper()
@@ -2947,10 +2957,10 @@ Try setting b_lundef to false instead.'''.format(self.coredata.options[OptionKey
                     outputs.update(o)
 
         kwargs['include_directories'] = self.extract_incdirs(kwargs)
-        target = targetclass(name, self.subdir, self.subproject, for_machine, srcs, struct, objs, self.environment, kwargs)
+        target = targetclass(name, self.subdir, self.subproject, for_machine, srcs, struct, objs,
+                             self.environment, self.compilers[for_machine], kwargs)
         target.project_version = self.project_version
 
-        self.add_stdlib_info(target)
         self.add_target(name, target)
         self.project_args_frozen = True
         return target
@@ -2972,17 +2982,8 @@ This will become a hard error in the future.''', location=self.current_node)
                 cleaned_items.append(i)
             kwargs['d_import_dirs'] = cleaned_items
 
-    def get_used_languages(self, target):
-        result = set()
-        for i in target.sources:
-            for lang, c in self.coredata.compilers[target.for_machine].items():
-                if c.can_compile(i):
-                    result.add(lang)
-                    break
-        return result
-
     def add_stdlib_info(self, target):
-        for l in self.get_used_languages(target):
+        for l in target.compilers.keys():
             dep = self.build.stdlibs[target.for_machine].get(l, None)
             if dep:
                 target.add_deps(dep)