[C++20] [Modules] Embed all source files for C++20 Modules

Author: ChuanqiXu9

clang/include/clang/CodeGen/CodeGenAction.h

@@ -57,7 +57,7 @@ class CodeGenAction : public ASTFrontendAction {
   bool loadLinkModules(CompilerInstance &CI);
 
 protected:
-  bool BeginSourceFileAction(CompilerInstance &CI) override;
+  bool BeginInvocation(CompilerInstance &CI) override;
 
   /// Create a new code generation action.  If the optional \p _VMContext
   /// parameter is supplied, the action uses it without taking ownership,

clang/include/clang/Frontend/FrontendActions.h

@@ -152,11 +152,13 @@ class GenerateModuleFromModuleMapAction : public GenerateModuleAction {
   CreateOutputFile(CompilerInstance &CI, StringRef InFile) override;
 };
 
+bool BeginInvocationForModules(CompilerInstance &CI);
+
 /// Generates full BMI (which contains full information to generate the object
 /// files) for C++20 Named Modules.
 class GenerateModuleInterfaceAction : public GenerateModuleAction {
 protected:
-  bool BeginSourceFileAction(CompilerInstance &CI) override;
+  bool BeginInvocation(CompilerInstance &CI) override;
 
   std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
                                                  StringRef InFile) override;

clang/include/clang/Serialization/ModuleFile.h

@@ -88,13 +88,13 @@ class InputFile {
 
   InputFile(FileEntryRef File, bool isOverridden = false,
             bool isOutOfDate = false) {
-    assert(!(isOverridden && isOutOfDate) &&
-           "an overridden cannot be out-of-date");
     unsigned intVal = 0;
-    if (isOverridden)
-      intVal = Overridden;
-    else if (isOutOfDate)
+    // Make isOutOfDate with higher priority than isOverridden.
+    // It is possible if the recorded hash value mismatches.
+    if (isOutOfDate)
       intVal = OutOfDate;
+    else if (isOverridden)
+      intVal = Overridden;
     Val.setPointerAndInt(&File.getMapEntry(), intVal);
   }
 

clang/lib/CodeGen/CodeGenAction.cpp

@@ -969,9 +969,10 @@ CodeGenerator *CodeGenAction::getCodeGenerator() const {
   return BEConsumer->getCodeGenerator();
 }
 
-bool CodeGenAction::BeginSourceFileAction(CompilerInstance &CI) {
+bool CodeGenAction::BeginInvocation(CompilerInstance &CI) {
   if (CI.getFrontendOpts().GenReducedBMI)
-    CI.getLangOpts().setCompilingModule(LangOptions::CMK_ModuleInterface);
+    return BeginInvocationForModules(CI);
+
   return true;
 }
 

clang/lib/Frontend/FrontendActions.cpp

@@ -262,11 +262,20 @@ GenerateModuleFromModuleMapAction::CreateOutputFile(CompilerInstance &CI,
                                     /*ForceUseTemporary=*/true);
 }
 
-bool GenerateModuleInterfaceAction::BeginSourceFileAction(
-    CompilerInstance &CI) {
+bool clang::BeginInvocationForModules(CompilerInstance &CI) {
+  // Embed all module files for named modules.
+  // See https://github.com/llvm/llvm-project/issues/72383 for discussion.
+  CI.getFrontendOpts().ModulesEmbedAllFiles = true;
   CI.getLangOpts().setCompilingModule(LangOptions::CMK_ModuleInterface);
+  return true;
+}
 
-  return GenerateModuleAction::BeginSourceFileAction(CI);
+bool GenerateModuleInterfaceAction::BeginInvocation(
+    CompilerInstance &CI) {
+  if (!BeginInvocationForModules(CI))
+    return false;
+
+  return GenerateModuleAction::BeginInvocation(CI);
 }
 
 std::unique_ptr<ASTConsumer>