diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -1115,6 +1115,14 @@
   LLVMContext &Ctx = TheModule->getContext();
   Ctx.setInlineAsmDiagnosticHandler(BitcodeInlineAsmDiagHandler, &Diagnostics);
 
+  // Restore any diagnostic handler previously set before returning from this
+  // function.
+  struct RAII {
+    LLVMContext &Ctx;
+    std::unique_ptr<DiagnosticHandler> PrevHandler = Ctx.getDiagnosticHandler();
+    ~RAII() { Ctx.setDiagnosticHandler(std::move(PrevHandler)); }
+  } _{Ctx};
+
   // Set clang diagnostic handler. To do this we need to create a fake
   // BackendConsumer.
   BackendConsumer Result(BA, CI.getDiagnostics(), CI.getHeaderSearchOpts(),
diff --git a/llvm/include/llvm/IR/LLVMContext.h b/llvm/include/llvm/IR/LLVMContext.h
--- a/llvm/include/llvm/IR/LLVMContext.h
+++ b/llvm/include/llvm/IR/LLVMContext.h
@@ -190,10 +190,11 @@
       DiagnosticHandler::DiagnosticHandlerTy DiagHandler,
       void *DiagContext = nullptr, bool RespectFilters = false);
 
-  /// setDiagnosticHandler - This method sets unique_ptr to object of DiagnosticHandler
-  /// to provide custom diagnostic handling. The first argument is unique_ptr of object
-  /// of type DiagnosticHandler or a derived of that.   The third argument should be
-  /// set to true if the handler only expects enabled diagnostics.
+  /// setDiagnosticHandler - This method sets unique_ptr to object of
+  /// DiagnosticHandler to provide custom diagnostic handling. The first
+  /// argument is unique_ptr of object of type DiagnosticHandler or a derived
+  /// of that. The second argument should be set to true if the handler only
+  /// expects enabled diagnostics.
   ///
   /// Ownership of this pointer is moved to LLVMContextImpl.
   void setDiagnosticHandler(std::unique_ptr<DiagnosticHandler> &&DH,
@@ -211,7 +212,7 @@
   /// setDiagnosticHandler.
   const DiagnosticHandler *getDiagHandlerPtr() const;
 
-  /// getDiagnosticHandler - transfers owenership of DiagnosticHandler unique_ptr
+  /// getDiagnosticHandler - transfers ownership of DiagnosticHandler unique_ptr
   /// to caller.
   std::unique_ptr<DiagnosticHandler> getDiagnosticHandler();