diff --git a/llvm/lib/Support/ManagedStatic.cpp b/llvm/lib/Support/ManagedStatic.cpp
--- a/llvm/lib/Support/ManagedStatic.cpp
+++ b/llvm/lib/Support/ManagedStatic.cpp
@@ -18,16 +18,10 @@
 using namespace llvm;
 
 static const ManagedStaticBase *StaticList = nullptr;
-static std::recursive_mutex *ManagedStaticMutex = nullptr;
-static llvm::once_flag mutex_init_flag;
-
-static void initializeMutex() {
-  ManagedStaticMutex = new std::recursive_mutex();
-}
 
 static std::recursive_mutex *getManagedStaticMutex() {
-  llvm::call_once(mutex_init_flag, initializeMutex);
-  return ManagedStaticMutex;
+  static std::recursive_mutex m;
+  return &m;
 }
 
 void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
@@ -75,9 +69,10 @@
 }
 
 /// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
+/// IMPORTANT: it's only safe to call llvm_shutdown() in single thread,
+/// without any other threads executing LLVM APIs.
+/// llvm_shutdown() should be the last use of LLVM APIs.
 void llvm::llvm_shutdown() {
-  std::lock_guard<std::recursive_mutex> Lock(*getManagedStaticMutex());
-
   while (StaticList)
     StaticList->destroy();
 }