diff --git a/lib/Support/CrashRecoveryContext.cpp b/lib/Support/CrashRecoveryContext.cpp
index c2459256f8f..9d13fce9cc5 100644
--- a/lib/Support/CrashRecoveryContext.cpp
+++ b/lib/Support/CrashRecoveryContext.cpp
@@ -10,8 +10,8 @@
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
-#include "llvm/Support/Mutex.h"
 #include "llvm/Support/ThreadLocal.h"
+#include <mutex>
 #include <setjmp.h>
 using namespace llvm;
 
@@ -71,7 +71,7 @@ public:
 
 }
 
-static ManagedStatic<sys::Mutex> gCrashRecoveryContextMutex;
+static ManagedStatic<std::mutex> gCrashRecoveryContextMutex;
 static bool gCrashRecoveryEnabled = false;
 
 static ManagedStatic<sys::ThreadLocal<const CrashRecoveryContext>>
@@ -116,7 +116,7 @@ CrashRecoveryContext *CrashRecoveryContext::GetCurrent() {
 }
 
 void CrashRecoveryContext::Enable() {
-  sys::ScopedLock L(*gCrashRecoveryContextMutex);
+  std::lock_guard<std::mutex> L(*gCrashRecoveryContextMutex);
   // FIXME: Shouldn't this be a refcount or something?
   if (gCrashRecoveryEnabled)
     return;
@@ -125,7 +125,7 @@ void CrashRecoveryContext::Enable() {
 }
 
 void CrashRecoveryContext::Disable() {
-  sys::ScopedLock L(*gCrashRecoveryContextMutex);
+  std::lock_guard<std::mutex> L(*gCrashRecoveryContextMutex);
   if (!gCrashRecoveryEnabled)
     return;
   gCrashRecoveryEnabled = false;
diff --git a/lib/Support/ManagedStatic.cpp b/lib/Support/ManagedStatic.cpp
index c51ef96e9f8..053493f72fb 100644
--- a/lib/Support/ManagedStatic.cpp
+++ b/lib/Support/ManagedStatic.cpp
@@ -12,21 +12,20 @@
 
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Config/config.h"
-#include "llvm/Support/Mutex.h"
 #include "llvm/Support/Threading.h"
 #include <cassert>
 #include <mutex>
 using namespace llvm;
 
 static const ManagedStaticBase *StaticList = nullptr;
-static sys::Mutex *ManagedStaticMutex = nullptr;
+static std::recursive_mutex *ManagedStaticMutex = nullptr;
 static llvm::once_flag mutex_init_flag;
 
 static void initializeMutex() {
-  ManagedStaticMutex = new sys::Mutex();
+  ManagedStaticMutex = new std::recursive_mutex();
 }
 
-static sys::Mutex* getManagedStaticMutex() {
+static std::recursive_mutex *getManagedStaticMutex() {
   llvm::call_once(mutex_init_flag, initializeMutex);
   return ManagedStaticMutex;
 }
@@ -35,7 +34,7 @@ void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
                                               void (*Deleter)(void*)) const {
   assert(Creator);
   if (llvm_is_multithreaded()) {
-    std::lock_guard<sys::Mutex> Lock(*getManagedStaticMutex());
+    std::lock_guard<std::recursive_mutex> Lock(*getManagedStaticMutex());
 
     if (!Ptr.load(std::memory_order_relaxed)) {
       void *Tmp = Creator();
@@ -77,7 +76,7 @@ void ManagedStaticBase::destroy() const {
 
 /// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
 void llvm::llvm_shutdown() {
-  std::lock_guard<sys::Mutex> Lock(*getManagedStaticMutex());
+  std::lock_guard<std::recursive_mutex> Lock(*getManagedStaticMutex());
 
   while (StaticList)
     StaticList->destroy();
diff --git a/lib/Support/Unix/Process.inc b/lib/Support/Unix/Process.inc
index 86101e47391..dfe81d7e283 100644
--- a/lib/Support/Unix/Process.inc
+++ b/lib/Support/Unix/Process.inc
@@ -15,7 +15,6 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Config/config.h"
 #include "llvm/Support/ManagedStatic.h"
-#include "llvm/Support/Mutex.h"
 #include <mutex>
 #if HAVE_FCNTL_H
 #include <fcntl.h>
@@ -327,13 +326,13 @@ extern "C" int tigetnum(char *capname);
 #endif
 
 #ifdef HAVE_TERMINFO
-static ManagedStatic<sys::Mutex> TermColorMutex;
+static ManagedStatic<std::mutex> TermColorMutex;
 #endif
 
 static bool terminalHasColors(int fd) {
 #ifdef HAVE_TERMINFO
   // First, acquire a global lock because these C routines are thread hostile.
-  std::lock_guard<sys::Mutex> G(*TermColorMutex);
+  std::lock_guard<std::mutex> G(*TermColorMutex);
 
   int errret = 0;
   if (setupterm(nullptr, fd, &errret) != 0)