diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 1b3e81b6f7d9..e43bdb42269e 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -980,7 +980,7 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
     goto error;
 
   if (OverrideMainBuffer) {
-    std::string ModName = "$" + PreambleFile;
+    std::string ModName = PreambleFile;
     TranslateStoredDiagnostics(Clang->getModuleManager(), ModName,
                                getSourceManager(), PreambleDiagnostics,
                                StoredDiagnostics);
@@ -2293,7 +2293,7 @@ void ASTUnit::CodeComplete(llvm::StringRef File, unsigned Line, unsigned Column,
   if (Act->BeginSourceFile(*Clang.get(), Clang->getFrontendOpts().Inputs[0].second,
                            Clang->getFrontendOpts().Inputs[0].first)) {
     if (OverrideMainBuffer) {
-      std::string ModName = "$" + PreambleFile;
+      std::string ModName = PreambleFile;
       TranslateStoredDiagnostics(Clang->getModuleManager(), ModName,
                                  getSourceManager(), PreambleDiagnostics,
                                  StoredDiagnostics);
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index ecb24e730a96..424d6313ec2c 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -2643,8 +2643,8 @@ ASTReader::ASTReadResult ASTReader::ReadASTCore(llvm::StringRef FileName,
   else
     FirstInSource = &F;
   F.Loaders.push_back(Prev);
-  // A non-module AST file's module name is $filename.
-  Modules["$" + FileName.str()] = &F;
+
+  Modules[FileName.str()] = &F;
 
   // Set the AST file name.
   F.FileName = FileName;