1 files changed, 25 insertions, 0 deletions
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 0fc9a4e96b0..770a2cf4df5 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -866,6 +866,31 @@ void ASTContext::PrintStats() const {
   BumpAlloc.PrintStats();
 }
 
+void ASTContext::mergeDefinitionIntoModule(NamedDecl *ND, Module *M,
+                                           bool NotifyListeners) {
+  if (NotifyListeners)
+    if (auto *Listener = getASTMutationListener())
+      Listener->RedefinedHiddenDefinition(ND, M);
+
+  if (getLangOpts().ModulesLocalVisibility)
+    MergedDefModules[ND].push_back(M);
+  else
+    ND->setHidden(false);
+}
+
+void ASTContext::deduplicateMergedDefinitonsFor(NamedDecl *ND) {
+  auto It = MergedDefModules.find(ND);
+  if (It == MergedDefModules.end())
+    return;
+
+  auto &Merged = It->second;
+  llvm::DenseSet<Module*> Found;
+  for (Module *&M : Merged)
+    if (!Found.insert(M).second)
+      M = nullptr;
+  Merged.erase(std::remove(Merged.begin(), Merged.end(), nullptr), Merged.end());
+}
+
 ExternCContextDecl *ASTContext::getExternCContextDecl() const {
   if (!ExternCContext)
     ExternCContext = ExternCContextDecl::Create(*this, getTranslationUnitDecl());