Detect dependency changes in Windows rc compiler

The `rc.exe` resource compiler neither provides *depfile* support nor
allows showing includes, as is possible with C or C++ compilers.
Therefore, changes to files included by the `.rc` file did not trigger
recompilation of the resource file.

A workaround was added to *meson* by calling the preprocessor on the
`.rc` file to detect the included headers and adding the result as a
dependency to the resource compilation.

3 files changed, 56 insertions, 7 deletions

diff --git a/docs/markdown/Windows-module.md b/docs/markdown/Windows-module.md
index 025f046cc..5ae828109 100644
--- a/docs/markdown/Windows-module.md
+++ b/docs/markdown/Windows-module.md
@@ -20,8 +20,11 @@ Compiles Windows `rc` files specified in the positional arguments.
 Returns a list of `CustomTarget` objects that you put in the list of sources for
 the target you want to have the resources in.
 
-*Since 0.61.0* CustomTargetIndexes and CustomTargets with more than out output
-*may be used as positional arguments.
+*Since 0.61.0* `CustomTargetIndexes` and `CustomTargets` with more than one output
+may be used as positional arguments.
+
+*Since 1.10.0* Changes to included header files are now detected when using
+`rc.exe` resource compiler.
 
 This method has the following keyword arguments:
 
diff --git a/docs/markdown/snippets/windows_rc_depfile.md b/docs/markdown/snippets/windows_rc_depfile.md
new file mode 100644
index 000000000..8a2c9ac6f
--- /dev/null
+++ b/docs/markdown/snippets/windows_rc_depfile.md
@@ -0,0 +1,10 @@
+## windows.compile_resources now detects header changes with rc.exe
+
+The `rc.exe` resource compiler neither provides *depfile* support nor
+allows showing includes, as is possible with C or C++ compilers.
+Therefore, changes to files included by the `.rc` file did not trigger
+recompilation of the resource file.
+
+A workaround was added to *meson* by calling the preprocessor on the
+`.rc` file to detect the included headers and adding the result as a
+dependency to the resource compilation.
diff --git a/mesonbuild/modules/windows.py b/mesonbuild/modules/windows.py
index 29ae96b08..17fc8abe4 100644
--- a/mesonbuild/modules/windows.py
+++ b/mesonbuild/modules/windows.py
@@ -22,13 +22,13 @@ if T.TYPE_CHECKING:
     from . import ModuleState
     from ..compilers import Compiler
     from ..interpreter import Interpreter
+    from ..interpreter.interpreter import SourceOutputs
 
     from typing_extensions import TypedDict
 
     class CompileResources(TypedDict):
-
         depend_files: T.List[mesonlib.FileOrString]
-        depends: T.List[T.Union[build.BuildTarget, build.CustomTarget]]
+        depends: T.List[T.Union[build.BuildTarget, build.CustomTarget, build.CustomTargetIndex]]
         include_directories: T.List[T.Union[str, build.IncludeDirs]]
         args: T.List[str]
 
@@ -102,6 +102,33 @@ class WindowsModule(ExtensionModule):
 
         return self._rescomp
 
+    def get_preprocessor_target(self,
+                                name_formatted: str,
+                                src: T.Union[str, mesonlib.File, build.CustomTarget, build.CustomTargetIndex],
+                                include_directories: T.List[build.IncludeDirs],
+                                state: ModuleState) -> build.CustomTargetIndex:
+        compiler = self.detect_compiler(state.environment.coredata.compilers[MachineChoice.HOST])
+        _sources: T.List[T.Union[mesonlib.File, build.CustomTarget, build.CustomTargetIndex, build.GeneratedList]] = self.interpreter.source_strings_to_files([src])
+        sources = T.cast('T.List[SourceOutputs]', _sources)
+
+        tg = build.CompileTarget(
+            name_formatted,
+            state.subdir,
+            state.subproject,
+            state.environment,
+            sources,
+            '@PLAINNAME@.i',
+            compiler.get_preprocessor(),
+            state.backend,
+            ['-DRC_INVOKED'],
+            include_directories,
+            [],
+            [])
+        self.interpreter.add_target(tg.name, tg)
+
+        private_dir = os.path.relpath(state.backend.get_target_private_dir(tg), state.subdir)
+        return build.CustomTargetIndex(tg, os.path.join(private_dir, tg.outputs[0]))
+
     @typed_pos_args('windows.compile_resources', varargs=(str, mesonlib.File, build.CustomTarget, build.CustomTargetIndex), min_varargs=1)
     @typed_kwargs(
         'windows.compile_resources',
@@ -121,7 +148,8 @@ class WindowsModule(ExtensionModule):
                 extra_args += state.get_include_args([
                     build.IncludeDirs('', [], False, [os.path.join('@BUILD_ROOT@', self.interpreter.backend.get_target_dir(d))])
                 ])
-        extra_args += state.get_include_args(kwargs['include_directories'])
+        include_directories = self.interpreter.extract_incdirs(kwargs)
+        extra_args += state.get_include_args(include_directories)
 
         rescomp, rescomp_type = self._find_resource_compiler(state)
         if rescomp_type == ResourceCompilerType.rc:
@@ -178,12 +206,20 @@ class WindowsModule(ExtensionModule):
             command.append(rescomp)
             command.extend(res_args)
             depfile: T.Optional[str] = None
-            # instruct binutils windres to generate a preprocessor depfile
+            extra_depends = wrc_depends.copy()
             if rescomp_type == ResourceCompilerType.windres:
+                # instruct binutils windres to generate a preprocessor depfile
                 depfile = f'{output}.d'
                 command.extend(['--preprocessor-arg=-MD',
                                 '--preprocessor-arg=-MQ@OUTPUT@',
                                 '--preprocessor-arg=-MF@DEPFILE@'])
+            elif rescomp_type == ResourceCompilerType.rc:
+                # use preprocessor to detect header dependencies
+                extra_depends.append(self.get_preprocessor_target(
+                    name_formatted + '_i',
+                    src,
+                    include_directories,
+                    state))
 
             res_targets.append(build.CustomTarget(
                 name_formatted,
@@ -195,7 +231,7 @@ class WindowsModule(ExtensionModule):
                 [output],
                 depfile=depfile,
                 depend_files=wrc_depend_files,
-                extra_depends=wrc_depends,
+                extra_depends=extra_depends,
                 description='Compiling Windows resource {}',
             ))