3 files changed, 29 insertions, 1 deletions
diff --git a/clang/lib/Serialization/ASTCommon.h b/clang/lib/Serialization/ASTCommon.h
index 09e0a40f1c9..79d1817159c 100644
--- a/clang/lib/Serialization/ASTCommon.h
+++ b/clang/lib/Serialization/ASTCommon.h
@@ -35,7 +35,8 @@ enum DeclUpdateKind {
   UPD_DECL_MARKED_USED,
   UPD_MANGLING_NUMBER,
   UPD_STATIC_LOCAL_NUMBER,
-  UPD_DECL_MARKED_OPENMP_THREADPRIVATE
+  UPD_DECL_MARKED_OPENMP_THREADPRIVATE,
+  UPD_DECL_EXPORTED
 };
 
 TypeIdx TypeIdxFromBuiltin(const BuiltinType *BT);
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 10de9f754de..184e6d7772a 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -3793,10 +3793,24 @@ void ASTDeclReader::UpdateDecl(Decl *D, ModuleFile &ModuleFile,
     case UPD_STATIC_LOCAL_NUMBER:
       Reader.Context.setStaticLocalNumber(cast<VarDecl>(D), Record[Idx++]);
       break;
+
     case UPD_DECL_MARKED_OPENMP_THREADPRIVATE:
       D->addAttr(OMPThreadPrivateDeclAttr::CreateImplicit(
           Reader.Context, ReadSourceRange(Record, Idx)));
       break;
+
+    case UPD_DECL_EXPORTED:
+      unsigned SubmoduleID = readSubmoduleID(Record, Idx);
+      Module *Owner = SubmoduleID ? Reader.getSubmodule(SubmoduleID) : nullptr;
+      if (Owner && Owner->NameVisibility != Module::AllVisible) {
+        // If Owner is made visible at some later point, make this declaration
+        // visible too.
+        Reader.HiddenNamesMap[Owner].HiddenDecls.push_back(D);
+      } else {
+        // The declaration is now visible.
+        D->Hidden = false;
+      }
+      break;
     }
   }
 }
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 53da0e674cd..fabc0d46989 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -4927,10 +4927,15 @@ void ASTWriter::WriteDeclUpdatesBlocks(RecordDataImpl &OffsetsRecord) {
       case UPD_STATIC_LOCAL_NUMBER:
         Record.push_back(Update.getNumber());
         break;
+
       case UPD_DECL_MARKED_OPENMP_THREADPRIVATE:
         AddSourceRange(D->getAttr<OMPThreadPrivateDeclAttr>()->getRange(),
                        Record);
         break;
+
+      case UPD_DECL_EXPORTED:
+        Record.push_back(inferSubmoduleIDFromLocation(Update.getLoc()));
+        break;
       }
     }
 
@@ -6074,3 +6079,11 @@ void ASTWriter::DeclarationMarkedOpenMPThreadPrivate(const Decl *D) {
 
   DeclUpdates[D].push_back(DeclUpdate(UPD_DECL_MARKED_OPENMP_THREADPRIVATE));
 }
+
+void ASTWriter::RedefinedHiddenDefinition(const NamedDecl *D,
+                                          SourceLocation Loc) {
+  assert(!WritingAST && "Already writing the AST!");
+  assert(D->isHidden() && "expected a hidden declaration");
+  assert(D->isFromASTFile() && "hidden decl not from AST file");
+  DeclUpdates[D].push_back(DeclUpdate(UPD_DECL_EXPORTED, Loc));
+}