shuriken: Copy source file to build dir for "import std"

Problem with the previous approach: CLion wouldn't recognize the std module, unless it's included in the compdb (but then /usr/include/c++/.../bits is listed as part of the project -.-)

tools/shuriken.py

@@ -497,7 +497,7 @@ class ShurikenCli:
 
 CompileTargetCpp = namedtuple('CompileTargetCpp', ['src', 'obj'])
 CompileTargetCppm = namedtuple('CompileTargetCppm', ['src', 'obj', 'pcm'])
-CompileTargetStdModule = namedtuple('CompileTargetStdModule', ['src', 'pcm'])
+CompileTargetStdModule = namedtuple('CompileTargetStdModule', ['original_src', 'generated_src', 'pcm'])
 
 
 class NinjaFileGenerator:
@@ -552,7 +552,8 @@ class NinjaFileGenerator:
             std_module_sources = std_module_source_finder.find_module_sources(['std'])
             for module_name, module_src_path in std_module_sources.items():
                 self.compile_targets_std_module.append(CompileTargetStdModule(
-                    src=str(module_src_path),
+                    original_src=str(module_src_path),
+                    generated_src=f"$builddir/generated/stdlib/{module_name}.cppm",
                     pcm=f"$builddir/pcm/{module_name}.pcm",
                 ))
 
@@ -589,6 +590,10 @@ linker_args = {target_config.merged_linker_args}
 
 # -- RULES
 
+# Rule to copy an arbitrary file (or multiple) from in to out
+rule copy
+    command = cp $in $out
+
 # Rule to compile a .cpp file to a .o file
 rule cpp
     command = {target_config.cpp_compiler} $cpp_flags -c $in -o $out
@@ -607,7 +612,7 @@ rule link
 
 # Rule to generate a compilation database (JSON file) from the build targets defined in a Ninja file
 rule generate_compdb
-    command = ninja -f $in -t compdb cpp cppm > $out
+    command = ninja -f $in -t compdb cpp cppm std_module > $out
 
 # Rule to generate a Ninja dyndep file for C++ module dependencies based on a compilation database
 rule generate_dyndeps
@@ -617,7 +622,7 @@ rule generate_dyndeps
 # -- STATIC BUILD TARGETS
 
 # Generate compilation database from default target Ninja file
-build $compdb_file: generate_compdb {self.config.get_ninja_file_path(config.default_target)}
+build $compdb_file: generate_compdb {self.config.get_ninja_file_path(config.default_target)} | generate_source_files
 
 # Shortcut alias to generate compilation database
 build compdb: phony $compdb_file
@@ -632,11 +637,18 @@ build $dyndep_file: generate_dyndeps $compdb_file
 build $builddir/{target_config.output_file}: link {' '.join(self.link_target_obj_files)}
 default $builddir/{target_config.output_file}
 
+# Phony target that depends on all generated source files
+build generate_source_files: phony {self.list_generated_source_files()}
+
 {self.render_compile_targets()}
 
 # End of build.{target}.ninja
 """.strip()
 
+    def list_generated_source_files(self) -> str:
+        generated_files = [target.generated_src for target in self.compile_targets_std_module]
+        return ' '.join(generated_files)
+
     def render_compile_targets(self) -> str:
         rendered_targets = list(map(self.render_compile_target_std_module, self.compile_targets_std_module))
         rendered_targets += list(map(self.render_compile_target_cpp, self.compile_targets_cpp))
@@ -661,7 +673,9 @@ build {target.obj} | {target.pcm}: cppm {target.src} || $dyndep_file
     @staticmethod
     def render_compile_target_std_module(target: CompileTargetStdModule) -> str:
         return f"""
-build {target.pcm}: std_module {target.src} || $dyndep_file
+build {target.generated_src}: copy {target.original_src}
+
+build {target.pcm}: std_module {target.generated_src} || $dyndep_file
     dyndep = $dyndep_file
 """.strip()
 
@@ -683,10 +697,6 @@ class BuildDependencyParser:
         # Map of module names to PCM file paths
         module_map: dict[str, Path] = {}
 
-        # Add standard library modules to module map (if "import std" support is enabled)
-        if self.config.enable_import_std:
-            module_map['std'] = Path(target_build_dir, 'pcm', 'std.pcm')
-
         # Validate module name and path convention, construct map of module names to PCM file paths
         for rule in parsed_p1689['rules']:
             provides = rule.get('provides', [])
@@ -697,20 +707,16 @@ class BuildDependencyParser:
                 module_name: str = provides[0]['logical-name']
                 assert module_name not in module_map, f'Module "{module_name}" is provided more than once: {rule}'
 
-                expected_source_path = str(Path(source_dir, module_name.replace('.', '/') + '.cppm'))
-                assert provides[0]['source-path'] == expected_source_path, \
-                    f"Module name does not match source path: {rule}"
+                if module_name != 'std':
+                    expected_source_path = str(Path(source_dir, module_name.replace('.', '/') + '.cppm'))
+                    assert provides[0]['source-path'] == expected_source_path, \
+                        f"Module name does not match source path: {rule}"
 
                 module_map[module_name] = Path(target_build_dir, 'pcm', module_name + '.pcm')
 
         # Collect all module dependencies to generate dyndeps
         build_dependencies: dict[Path, list[Path]] = {}
 
-        # If "import std" support is enabled, we need to add std to the build dependencies, even though it doesn't have
-        # any dependencies itself. This is needed, otherwise the module won't be built automatically.
-        if self.config.enable_import_std:
-            build_dependencies[target_build_dir / 'pcm/std.pcm'] = []
-
         # Parse rules and get module dependencies
         for rule in parsed_p1689['rules']:
             # Compilation database contains "build/{default_target}" paths, we need to map them to "build/{target}"