build: differentiate build directory according to a subproject's build machine

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

mesonbuild/build.py

@@ -309,6 +309,10 @@ class BuildProject:
     project_args: PerMachine[T.Dict[Language, T.List[str]]] = field(default_factory=lambda: PerMachine({}, {}))
     project_link_args: PerMachine[T.Dict[Language, T.List[str]]] = field(default_factory=lambda: PerMachine({}, {}))
 
+    @lazy_property
+    def prefix(self) -> str:
+        return 'build.' if self.for_machine is MachineChoice.BUILD else ''
+
 
 # literally everything isn't dataclass stuff
 class Build:
@@ -491,6 +495,7 @@ class IncludeDirs(HoldableObject):
     curdir: str
     incdirs: T.List[str]
     is_system: bool
+    build_project: BuildProject
     extra_build_dirs: T.List[str] = field(default_factory=list)
 
     def abs_string_list(self, sourcedir: str, builddir: str) -> T.List[str]:
@@ -501,12 +506,14 @@ class IncludeDirs(HoldableObject):
             be added if this is unset
         :returns: A list of strings (without compiler argument)
         """
+        bsubdir = self.build_project.prefix + self.curdir
+
         strlist: T.List[str] = []
         for idir in self.incdirs:
             strlist.append(os.path.join(sourcedir, self.curdir, idir))
-            strlist.append(os.path.join(builddir, self.curdir, idir))
+            strlist.append(os.path.join(builddir, bsubdir, idir))
         for idir in self.extra_build_dirs:
-            strlist.append(os.path.join(builddir, self.curdir, idir))
+            strlist.append(os.path.join(builddir, bsubdir, idir))
         return strlist
 
     def rel_string_list(self, build_to_src: str, build_root: T.Optional[str] = None) -> T.List[str]:
@@ -518,13 +525,15 @@ class IncludeDirs(HoldableObject):
         :return: A list if strings (without compiler argument)
         """
         strlist: T.List[str] = []
+        bsubdir = self.build_project.prefix + self.curdir
+
         for idirs, add_src in [(self.incdirs, True), (self.extra_build_dirs, False)]:
             for idir in idirs:
-                dir = os.path.normpath(os.path.join(self.curdir, idir))
-                if build_root is None or os.path.isdir(os.path.join(build_root, dir)):
-                    strlist.append(dir)
+                bld_dir = os.path.normpath(os.path.join(bsubdir, idir))
+                if build_root is None or os.path.isdir(os.path.join(build_root, bld_dir)):
+                    strlist.append(bld_dir)
                 if add_src:
-                    strlist.append(os.path.normpath(os.path.join(build_to_src, dir)))
+                    strlist.append(os.path.normpath(os.path.join(build_to_src, self.curdir, idir)))
 
         return strlist
 
@@ -651,9 +660,9 @@ class Target(HoldableObject, metaclass=SimpleABC):
                 Target "{self.name}" has a path separator in its name.
                 This is not supported, it can cause unexpected failures and will become
                 a hard error in the future.'''))
-        self.builddir = self.subdir
+        self.builddir = self.build_project.prefix + self.subdir
         if self.build_subdir:
-            self.builddir = os.path.join(self.subdir, self.build_subdir)
+            self.builddir = os.path.join(self.builddir, self.build_subdir)
 
     # dataclass comparators?
     def __lt__(self, other: object) -> bool:
@@ -1586,7 +1595,8 @@ class BuildTarget(Target):
     def add_include_dirs(self, args: T.Sequence['IncludeDirs'], set_is_system: str = 'preserve') -> None:
         if set_is_system != 'preserve':
             is_system = set_is_system == 'system'
-            self.include_dirs.extend([IncludeDirs(x.curdir, x.incdirs, is_system, x.extra_build_dirs) for x in args])
+            self.include_dirs.extend([IncludeDirs(x.curdir, x.incdirs, is_system, x.build_project,
+                                                  x.extra_build_dirs) for x in args])
         else:
             self.include_dirs.extend(args)
 

mesonbuild/interpreter/interpreter.py

@@ -2994,7 +2994,7 @@ class Interpreter(InterpreterBase, HoldableObject):
             absdir_build = os.path.join(absbase_build, a)
             if not os.path.isdir(absdir_src) and not os.path.isdir(absdir_build):
                 raise InvalidArguments(f'Include dir {a} does not exist.')
-        i = build.IncludeDirs(self.subdir, incdir_strings, is_system)
+        i = build.IncludeDirs(self.subdir, incdir_strings, is_system, self.current_build_project())
         return i
 
     @typed_pos_args('add_test_setup', str)

mesonbuild/interpreter/interpreterobjects.py

@@ -1013,7 +1013,8 @@ class BuildTargetHolder(ObjectHolder[_BuildTarget]):
     @noKwargs
     @InterpreterObject.method('private_dir_include')
     def private_dir_include_method(self, args: T.List[TYPE_var], kwargs: TYPE_kwargs) -> build.IncludeDirs:
-        return build.IncludeDirs('', [], False, [self.interpreter.backend.get_target_private_dir(self._target_object)])
+        return build.IncludeDirs('', [], False, self.interpreter.current_build_project(),
+                                 [self.interpreter.backend.get_target_private_dir(self._target_object)])
 
     @noPosargs
     @noKwargs

mesonbuild/modules/gnome.py

@@ -2314,7 +2314,8 @@ class GnomeModule(ExtensionModule):
         # - link with the correct library
         # - include the vapi and dependent vapi files in sources
         # - add relevant directories to include dirs
-        incs = [build.IncludeDirs(state.subdir, ['.'] + vapi_includes, False)]
+        incs = [build.IncludeDirs(state.subdir, ['.'] + vapi_includes, False,
+                state.current_build_project)]
         sources = [vapi_target] + vapi_depends
         rv = InternalDependency(None, incs, [], [], link_with, [], sources, [], [], {}, [], [], [])
         created_values.append(rv)

mesonbuild/modules/windows.py

@@ -124,7 +124,8 @@ class WindowsModule(ExtensionModule):
         for d in wrc_depends:
             if isinstance(d, build.CustomTarget):
                 extra_args += state.get_include_args([
-                    build.IncludeDirs('', [], False, [self.interpreter.backend.get_target_dir(d)])
+                    build.IncludeDirs('', [], False, state.current_build_project,
+                                      [self.interpreter.backend.get_target_dir(d)])
                 ])
         extra_args += state.get_include_args(kwargs['include_directories'], kwargs['implicit_include_directories'])