4 files changed, 90 insertions, 10 deletions

diff --git a/lib/AST/ASTDumper.cpp b/lib/AST/ASTDumper.cpp
index ef491ab06f8c..d89be0d9e6fa 100644
--- a/lib/AST/ASTDumper.cpp
+++ b/lib/AST/ASTDumper.cpp
@@ -1038,10 +1038,10 @@ void ASTDumper::dumpDecl(const Decl *D) {
     dumpSourceRange(D->getSourceRange());
     OS << ' ';
     dumpLocation(D->getLocation());
-    if (Module *M = D->getImportedOwningModule())
+    if (D->isFromASTFile())
+      OS << " imported";
+    if (Module *M = D->getOwningModule())
       OS << " in " << M->getFullModuleName();
-    else if (Module *M = D->getLocalOwningModule())
-      OS << " in (local) " << M->getFullModuleName();
     if (auto *ND = dyn_cast<NamedDecl>(D))
       for (Module *M : D->getASTContext().getModulesWithMergedDefinition(
                const_cast<NamedDecl *>(ND)))
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 0f2558e24ba5..a1342f477b68 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -47,9 +47,7 @@ bool Decl::isOutOfLine() const {
 
 TranslationUnitDecl::TranslationUnitDecl(ASTContext &ctx)
     : Decl(TranslationUnit, nullptr, SourceLocation()),
-      DeclContext(TranslationUnit), Ctx(ctx), AnonymousNamespace(nullptr) {
-  Hidden = Ctx.getLangOpts().ModulesLocalVisibility;
-}
+      DeclContext(TranslationUnit), Ctx(ctx), AnonymousNamespace(nullptr) {}
 
 //===----------------------------------------------------------------------===//
 // NamedDecl Implementation
diff --git a/lib/AST/DeclBase.cpp b/lib/AST/DeclBase.cpp
index 5c2c9cbd0180..f6f81692611d 100644
--- a/lib/AST/DeclBase.cpp
+++ b/lib/AST/DeclBase.cpp
@@ -75,7 +75,7 @@ void *Decl::operator new(std::size_t Size, const ASTContext &Ctx,
   assert(!Parent || &Parent->getParentASTContext() == &Ctx);
   // With local visibility enabled, we track the owning module even for local
   // declarations.
-  if (Ctx.getLangOpts().ModulesLocalVisibility) {
+  if (Ctx.getLangOpts().trackLocalOwningModule()) {
     // Ensure required alignment of the resulting object by adding extra
     // padding at the start if required.
     size_t ExtraAlign =
@@ -83,7 +83,9 @@ void *Decl::operator new(std::size_t Size, const ASTContext &Ctx,
     char *Buffer = reinterpret_cast<char *>(
         ::operator new(ExtraAlign + sizeof(Module *) + Size + Extra, Ctx));
     Buffer += ExtraAlign;
-    return new (Buffer) Module*(nullptr) + 1;
+    auto *ParentModule =
+        Parent ? cast<Decl>(Parent)->getOwningModule() : nullptr;
+    return new (Buffer) Module*(ParentModule) + 1;
   }
   return ::operator new(Size + Extra, Ctx);
 }
@@ -94,7 +96,7 @@ Module *Decl::getOwningModuleSlow() const {
 }
 
 bool Decl::hasLocalOwningModuleStorage() const {
-  return getASTContext().getLangOpts().ModulesLocalVisibility;
+  return getASTContext().getLangOpts().trackLocalOwningModule();
 }
 
 const char *Decl::getDeclKindName() const {
@@ -273,6 +275,8 @@ void Decl::setLexicalDeclContext(DeclContext *DC) {
     getMultipleDC()->LexicalDC = DC;
   }
   Hidden = cast<Decl>(DC)->Hidden;
+  if (Hidden && !isFromASTFile() && hasLocalOwningModuleStorage())
+    setLocalOwningModule(cast<Decl>(DC)->getOwningModule());
 }
 
 void Decl::setDeclContextsImpl(DeclContext *SemaDC, DeclContext *LexicalDC,
diff --git a/lib/AST/ODRHash.cpp b/lib/AST/ODRHash.cpp
index f4d314a6dd0d..24371db64d07 100644
--- a/lib/AST/ODRHash.cpp
+++ b/lib/AST/ODRHash.cpp
@@ -81,7 +81,35 @@ void ODRHash::AddDeclarationName(DeclarationName Name) {
   }
 }
 
-void ODRHash::AddNestedNameSpecifier(const NestedNameSpecifier *NNS) {}
+void ODRHash::AddNestedNameSpecifier(const NestedNameSpecifier *NNS) {
+  assert(NNS && "Expecting non-null pointer.");
+  const auto *Prefix = NNS->getPrefix();
+  AddBoolean(Prefix);
+  if (Prefix) {
+    AddNestedNameSpecifier(Prefix);
+  }
+  auto Kind = NNS->getKind();
+  ID.AddInteger(Kind);
+  switch (Kind) {
+  case NestedNameSpecifier::Identifier:
+    AddIdentifierInfo(NNS->getAsIdentifier());
+    break;
+  case NestedNameSpecifier::Namespace:
+    AddDecl(NNS->getAsNamespace());
+    break;
+  case NestedNameSpecifier::NamespaceAlias:
+    AddDecl(NNS->getAsNamespaceAlias());
+    break;
+  case NestedNameSpecifier::TypeSpec:
+  case NestedNameSpecifier::TypeSpecWithTemplate:
+    AddType(NNS->getAsType());
+    break;
+  case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Super:
+    break;
+  }
+}
+
 void ODRHash::AddTemplateName(TemplateName Name) {}
 void ODRHash::AddTemplateArgument(TemplateArgument TA) {}
 void ODRHash::AddTemplateParameterList(const TemplateParameterList *TPL) {}
@@ -335,6 +363,20 @@ public:
     Hash.AddQualType(T);
   }
 
+  void AddNestedNameSpecifier(const NestedNameSpecifier *NNS) {
+    Hash.AddBoolean(NNS);
+    if (NNS) {
+      Hash.AddNestedNameSpecifier(NNS);
+    }
+  }
+
+  void AddIdentifierInfo(const IdentifierInfo *II) {
+    Hash.AddBoolean(II);
+    if (II) {
+      Hash.AddIdentifierInfo(II);
+    }
+  }
+
   void VisitQualifiers(Qualifiers Quals) {
     ID.AddInteger(Quals.getAsOpaqueValue());
   }
@@ -414,6 +456,42 @@ public:
     AddQualType(T->getDecl()->getUnderlyingType().getCanonicalType());
     VisitType(T);
   }
+
+  void VisitTagType(const TagType *T) {
+    AddDecl(T->getDecl());
+    VisitType(T);
+  }
+
+  void VisitRecordType(const RecordType *T) { VisitTagType(T); }
+  void VisitEnumType(const EnumType *T) { VisitTagType(T); }
+
+  void VisitTypeWithKeyword(const TypeWithKeyword *T) {
+    ID.AddInteger(T->getKeyword());
+    VisitType(T);
+  };
+
+  void VisitDependentNameType(const DependentNameType *T) {
+    AddNestedNameSpecifier(T->getQualifier());
+    AddIdentifierInfo(T->getIdentifier());
+    VisitTypeWithKeyword(T);
+  }
+
+  void VisitDependentTemplateSpecializationType(
+      const DependentTemplateSpecializationType *T) {
+    AddIdentifierInfo(T->getIdentifier());
+    AddNestedNameSpecifier(T->getQualifier());
+    ID.AddInteger(T->getNumArgs());
+    for (const auto &TA : T->template_arguments()) {
+      Hash.AddTemplateArgument(TA);
+    }
+    VisitTypeWithKeyword(T);
+  }
+
+  void VisitElaboratedType(const ElaboratedType *T) {
+    AddNestedNameSpecifier(T->getQualifier());
+    AddQualType(T->getNamedType());
+    VisitTypeWithKeyword(T);
+  }
 };
 
 void ODRHash::AddType(const Type *T) {