3 files changed, 19 insertions, 62 deletions

diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index ca1d27e9505f..e7b0914641ff 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -93,11 +93,10 @@ Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
       ValueWithBytesObjCTypeMethod(nullptr), NSArrayDecl(nullptr),
       ArrayWithObjectsMethod(nullptr), NSDictionaryDecl(nullptr),
       DictionaryWithObjectsMethod(nullptr), GlobalNewDeleteDeclared(false),
-      TUKind(TUKind), NumSFINAEErrors(0), CachedFakeTopLevelModule(nullptr),
-      AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false),
-      NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1),
-      CurrentInstantiationScope(nullptr), DisableTypoCorrection(false),
-      TyposCorrected(0), AnalysisWarnings(*this),
+      TUKind(TUKind), NumSFINAEErrors(0), AccessCheckingSFINAE(false),
+      InNonInstantiationSFINAEContext(false), NonInstantiationEntries(0),
+      ArgumentPackSubstitutionIndex(-1), CurrentInstantiationScope(nullptr),
+      DisableTypoCorrection(false), TyposCorrected(0), AnalysisWarnings(*this),
       ThreadSafetyDeclCache(nullptr), VarDataSharingAttributesStack(nullptr),
       CurScope(nullptr), Ident_super(nullptr), Ident___float128(nullptr) {
   TUScope = nullptr;
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 2e069a9defaa..dca51b0e8c8e 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -16047,6 +16047,14 @@ void Sema::ActOnModuleBegin(SourceLocation DirectiveLoc, Module *Mod) {
     ModuleScopes.back().OuterVisibleModules = std::move(VisibleModules);
 
   VisibleModules.setVisible(Mod, DirectiveLoc);
+
+  // The enclosing context is now part of this module.
+  // FIXME: Consider creating a child DeclContext to hold the entities
+  // lexically within the module.
+  if (getLangOpts().trackLocalOwningModule()) {
+    cast<Decl>(CurContext)->setHidden(true);
+    cast<Decl>(CurContext)->setLocalOwningModule(Mod);
+  }
 }
 
 void Sema::ActOnModuleEnd(SourceLocation EomLoc, Module *Mod) {
@@ -16075,6 +16083,13 @@ void Sema::ActOnModuleEnd(SourceLocation EomLoc, Module *Mod) {
     DirectiveLoc = EomLoc;
   }
   BuildModuleInclude(DirectiveLoc, Mod);
+
+  // Any further declarations are in whatever module we returned to.
+  if (getLangOpts().trackLocalOwningModule()) {
+    cast<Decl>(CurContext)->setLocalOwningModule(getCurrentModule());
+    if (!getCurrentModule())
+      cast<Decl>(CurContext)->setHidden(false);
+  }
 }
 
 void Sema::createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
index c5b579a4b2e9..04350831c681 100644
--- a/lib/Sema/SemaLookup.cpp
+++ b/lib/Sema/SemaLookup.cpp
@@ -1326,62 +1326,6 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
   return !R.empty();
 }
 
-Module *Sema::getOwningModule(Decl *Entity) {
-  // If it's imported, grab its owning module.
-  Module *M = Entity->getImportedOwningModule();
-  if (M || !isa<NamedDecl>(Entity) || !cast<NamedDecl>(Entity)->isHidden())
-    return M;
-  assert(!Entity->isFromASTFile() &&
-         "hidden entity from AST file has no owning module");
-
-  if (!getLangOpts().ModulesLocalVisibility) {
-    // If we're not tracking visibility locally, the only way a declaration
-    // can be hidden and local is if it's hidden because it's parent is (for
-    // instance, maybe this is a lazily-declared special member of an imported
-    // class).
-    auto *Parent = cast<NamedDecl>(Entity->getDeclContext());
-    assert(Parent->isHidden() && "unexpectedly hidden decl");
-    return getOwningModule(Parent);
-  }
-
-  // It's local and hidden; grab or compute its owning module.
-  M = Entity->getLocalOwningModule();
-  if (M)
-    return M;
-
-  if (auto *Containing =
-          PP.getModuleContainingLocation(Entity->getLocation())) {
-    M = Containing;
-  } else if (Entity->isInvalidDecl() || Entity->getLocation().isInvalid()) {
-    // Don't bother tracking visibility for invalid declarations with broken
-    // locations.
-    cast<NamedDecl>(Entity)->setHidden(false);
-  } else {
-    // We need to assign a module to an entity that exists outside of any
-    // module, so that we can hide it from modules that we textually enter.
-    // Invent a fake module for all such entities.
-    if (!CachedFakeTopLevelModule) {
-      CachedFakeTopLevelModule =
-          PP.getHeaderSearchInfo().getModuleMap().findOrCreateModule(
-              "<top-level>", nullptr, false, false).first;
-
-      auto &SrcMgr = PP.getSourceManager();
-      SourceLocation StartLoc =
-          SrcMgr.getLocForStartOfFile(SrcMgr.getMainFileID());
-      auto &TopLevel = ModuleScopes.empty()
-                           ? VisibleModules
-                           : ModuleScopes[0].OuterVisibleModules;
-      TopLevel.setVisible(CachedFakeTopLevelModule, StartLoc);
-    }
-
-    M = CachedFakeTopLevelModule;
-  }
-
-  if (M)
-    Entity->setLocalOwningModule(M);
-  return M;
-}
-
 void Sema::makeMergedDefinitionVisible(NamedDecl *ND) {
   if (auto *M = getCurrentModule())
     Context.mergeDefinitionIntoModule(ND, M);
@@ -1520,7 +1464,6 @@ bool LookupResult::isVisibleSlow(Sema &SemaRef, NamedDecl *D) {
   if (SemaRef.getLangOpts().ModulesLocalVisibility) {
     DeclModule = SemaRef.getOwningModule(D);
     if (!DeclModule) {
-      // getOwningModule() may have decided the declaration should not be hidden.
       assert(!D->isHidden() && "hidden decl not from a module");
       return true;
     }