3 files changed, 7 insertions, 8 deletions
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 83830b51ed5..c35f7a94053 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -3250,18 +3250,15 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   bool IsCuda = JA.isOffloading(Action::OFK_Cuda);
   bool IsHIP = JA.isOffloading(Action::OFK_HIP);
   bool IsOpenMPDevice = JA.isDeviceOffloading(Action::OFK_OpenMP);
-  bool IsModulePrecompile =
-      isa<PrecompileJobAction>(JA) && JA.getType() == types::TY_ModuleFile;
   bool IsHeaderModulePrecompile = isa<HeaderModulePrecompileJobAction>(JA);
 
   // A header module compilation doesn't have a main input file, so invent a
   // fake one as a placeholder.
-  // FIXME: Pick the language based on the header file language.
   const char *ModuleName = [&]{
     auto *ModuleNameArg = Args.getLastArg(options::OPT_fmodule_name_EQ);
     return ModuleNameArg ? ModuleNameArg->getValue() : "";
   }();
-  InputInfo HeaderModuleInput(types::TY_CXXModule, ModuleName, ModuleName);
+  InputInfo HeaderModuleInput(Inputs[0].getType(), ModuleName, ModuleName);
 
   const InputInfo &Input =
       IsHeaderModulePrecompile ? HeaderModuleInput : Inputs[0];
@@ -3272,10 +3269,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   for (const InputInfo &I : Inputs) {
     if (&I == &Input) {
       // This is the primary input.
-    } else if (IsModulePrecompile &&
+    } else if (IsHeaderModulePrecompile &&
                types::getPrecompiledType(I.getType()) == types::TY_PCH) {
-      types::ID Expected =
-          types::lookupHeaderTypeForSourceType(Inputs[0].getType());
+      types::ID Expected = HeaderModuleInput.getType();
       if (I.getType() != Expected) {
         D.Diag(diag::err_drv_module_header_wrong_kind)
             << I.getFilename() << types::getTypeName(I.getType())
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index a9c51d49f65..719474dc765 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -372,6 +372,9 @@ static void InitializeFileRemapping(DiagnosticsEngine &Diags,
 void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
 
+  // The module manager holds a reference to the old preprocessor (if any).
+  ModuleManager.reset();
+
   // Create a PTH manager if we are using some form of a token cache.
   PTHManager *PTHMgr = nullptr;
   if (!PPOpts.TokenCache.empty())
diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index d44bf124ffc..13d2b728f58 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -523,7 +523,7 @@ void ModuleMap::diagnoseHeaderInclusion(Module *RequestingModule,
 
   // At this point, only non-modular includes remain.
 
-  if (LangOpts.ModulesStrictDeclUse) {
+  if (RequestingModule && LangOpts.ModulesStrictDeclUse) {
     Diags.Report(FilenameLoc, diag::err_undeclared_use_of_module)
         << RequestingModule->getTopLevelModule()->Name << Filename;
   } else if (RequestingModule && RequestingModuleIsModuleInterface &&