diff --git a/src/algorithm.cpp b/src/algorithm.cpp
index e9752b065..f036eb7ab 100644
--- a/src/algorithm.cpp
+++ b/src/algorithm.cpp
@@ -48,7 +48,7 @@ template bool __insertion_sort_incomplete<__less<long double>&, long double*>(lo
 template unsigned __sort5<__less<long double>&, long double*>(long double*, long double*, long double*, long double*, long double*, __less<long double>&);
 
 #ifndef _LIBCPP_HAS_NO_THREADS
-static __libcpp_mutex_t __rs_mut = _LIBCPP_MUTEX_INITIALIZER;
+_LIBCPP_SAFE_STATIC static __libcpp_mutex_t __rs_mut = _LIBCPP_MUTEX_INITIALIZER;
 #endif
 unsigned __rs_default::__c_ = 0;
 
diff --git a/src/exception.cpp b/src/exception.cpp
index e172f642d..96bd7ee59 100644
--- a/src/exception.cpp
+++ b/src/exception.cpp
@@ -32,8 +32,8 @@
     #define HAVE_DEPENDENT_EH_ABI 1
   #endif
 #elif !defined(__GLIBCXX__) // defined(LIBCXX_BUILDING_LIBCXXABI)
-  static std::terminate_handler  __terminate_handler;
-  static std::unexpected_handler __unexpected_handler;
+  _LIBCPP_SAFE_STATIC static std::terminate_handler  __terminate_handler;
+  _LIBCPP_SAFE_STATIC static std::unexpected_handler __unexpected_handler;
 #endif // defined(LIBCXX_BUILDING_LIBCXXABI)
 
 namespace std
diff --git a/src/memory.cpp b/src/memory.cpp
index b685d125b..514a2ce22 100644
--- a/src/memory.cpp
+++ b/src/memory.cpp
@@ -154,8 +154,8 @@ __shared_weak_count::__get_deleter(const type_info&) const _NOEXCEPT
 
 #if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
 
-static const std::size_t __sp_mut_count = 16;
-static __libcpp_mutex_t mut_back_imp[__sp_mut_count] =
+_LIBCPP_SAFE_STATIC static const std::size_t __sp_mut_count = 16;
+_LIBCPP_SAFE_STATIC static __libcpp_mutex_t mut_back[__sp_mut_count] =
 {
     _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER,
     _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER,
@@ -163,8 +163,6 @@ static __libcpp_mutex_t mut_back_imp[__sp_mut_count] =
     _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER
 };
 
-static mutex* mut_back = reinterpret_cast<std::mutex*>(mut_back_imp);
-
 _LIBCPP_CONSTEXPR __sp_mut::__sp_mut(void* p) _NOEXCEPT
    : __lx(p)
 {
@@ -173,13 +171,13 @@ _LIBCPP_CONSTEXPR __sp_mut::__sp_mut(void* p) _NOEXCEPT
 void
 __sp_mut::lock() _NOEXCEPT
 {
-    mutex& m = *static_cast<mutex*>(__lx);
+    auto m = static_cast<__libcpp_mutex_t*>(__lx);
     unsigned count = 0;
-    while (!m.try_lock())
+    while (__libcpp_mutex_trylock(m) != 0)
     {
         if (++count > 16)
         {
-            m.lock();
+            __libcpp_mutex_lock(m);
             break;
         }
         this_thread::yield();
@@ -189,13 +187,13 @@ __sp_mut::lock() _NOEXCEPT
 void
 __sp_mut::unlock() _NOEXCEPT
 {
-    static_cast<mutex*>(__lx)->unlock();
+    __libcpp_mutex_unlock(static_cast<__libcpp_mutex_t*>(__lx));
 }
 
 __sp_mut&
 __get_sp_mut(const void* p)
 {
-    static __sp_mut muts[__sp_mut_count] 
+    static __sp_mut muts[__sp_mut_count]
     {
         &mut_back[ 0], &mut_back[ 1], &mut_back[ 2], &mut_back[ 3],
         &mut_back[ 4], &mut_back[ 5], &mut_back[ 6], &mut_back[ 7],
diff --git a/src/mutex.cpp b/src/mutex.cpp
index 7226abc6a..dc530ceea 100644
--- a/src/mutex.cpp
+++ b/src/mutex.cpp
@@ -195,8 +195,8 @@ recursive_timed_mutex::unlock() _NOEXCEPT
 // keep in sync with:  7741191.
 
 #ifndef _LIBCPP_HAS_NO_THREADS
-static __libcpp_mutex_t mut = _LIBCPP_MUTEX_INITIALIZER;
-static __libcpp_condvar_t cv = _LIBCPP_CONDVAR_INITIALIZER;
+_LIBCPP_SAFE_STATIC static __libcpp_mutex_t mut = _LIBCPP_MUTEX_INITIALIZER;
+_LIBCPP_SAFE_STATIC static __libcpp_condvar_t cv = _LIBCPP_CONDVAR_INITIALIZER;
 #endif
 
 void