--- /dev/null
+++ libmalloc/libmalloc-792.80.2/src/locking.h
@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2015 Apple Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+#ifndef __LOCKING_H
+#define __LOCKING_H
+
+typedef struct lock_exclaves_s {
+	// Must match liblibc/include/libc/std/pthread.h
+	uint32_t _Alignas(16) opaque[4];
+} lock_exclave;
+
+// Exclaves always uses pthread.h to avoid alignment difference with os/lock.h
+#if !MALLOC_TARGET_EXCLAVES && !MALLOC_TARGET_EXCLAVES_INTROSPECTOR && __has_include(<os/lock.h>)
+# define MALLOC_HAS_OS_LOCK 1
+# include <os/lock.h>
+# if __has_include(<os/lock_private.h>)
+#  include <os/lock_private.h>
+# endif // __has_include(<os/lock_private.h>)
+# if defined(OS_UNFAIR_LOCK_INLINE) && OS_UNFAIR_LOCK_INLINE
+#  define os_unfair_lock_lock_with_options(lock, options) \
+		os_unfair_lock_lock_with_options_inline(lock, options)
+#  define os_unfair_lock_trylock(lock) \
+		os_unfair_lock_trylock_inline(lock)
+#  define os_unfair_lock_unlock(lock) \
+		os_unfair_lock_unlock_inline(lock)
+# endif // defined(OS_UNFAIR_LOCK_INLINE) && OS_UNFAIR_LOCK_INLINE
+
+typedef os_unfair_lock _malloc_lock_s;
+# define _MALLOC_LOCK_INIT OS_UNFAIR_LOCK_INIT
+#elif __has_include(<pthread.h>)
+# define MALLOC_HAS_OS_LOCK 0
+# include <pthread.h>
+
+# if MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+typedef lock_exclave _malloc_lock_s;
+
+#  define _MALLOC_LOCK_INIT (lock_exclave){0}
+# else
+_Static_assert(sizeof(lock_exclave) == sizeof(pthread_mutex_t),
+	"lock_exclave size must match pthread_mutex_t on EC");
+_Static_assert(_Alignof(lock_exclave) == _Alignof(pthread_mutex_t),
+	"lock_exclave alignment must match pthread_mutex_t on EC");
+
+typedef pthread_mutex_t _malloc_lock_s;
+#  define _MALLOC_LOCK_INIT (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER
+# endif // MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+#else
+# error "No platform locking support!"
+#endif // __has_include(<os/lock.h>)
+
+__attribute__((always_inline))
+static inline void
+_malloc_lock_init(_malloc_lock_s *lock) {
+#if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+	*lock = _MALLOC_LOCK_INIT;
+#else
+	malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+			"exclaves lock not supported");
+#endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+}
+
+MALLOC_ALWAYS_INLINE
+static inline void
+_malloc_lock_lock(_malloc_lock_s *lock) {
+#if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+# if MALLOC_HAS_OS_LOCK
+#  if __has_include(<os/lock_private.h>)
+	return os_unfair_lock_lock_with_options(lock, OS_UNFAIR_LOCK_ADAPTIVE_SPIN |
+											OS_UNFAIR_LOCK_DATA_SYNCHRONIZATION);
+#  else
+	return os_unfair_lock_lock(lock);
+#  endif // __has_include(<os/lock_private.h>)
+# else
+	if (pthread_mutex_lock(lock)) {
+		malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+				"Failed to acquire lock %p!\n", lock);
+	}
+# endif // MALLOC_HAS_OS_LOCK
+#else
+	malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+			"exclaves lock not supported");
+#endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+}
+
+MALLOC_ALWAYS_INLINE
+static inline bool
+_malloc_lock_trylock(_malloc_lock_s *lock) {
+#if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+# if MALLOC_HAS_OS_LOCK
+	return os_unfair_lock_trylock(lock);
+# else
+    return !pthread_mutex_trylock(lock);
+# endif // MALLOC_HAS_OS_LOCK
+#else
+	malloc_zone_error(MALLOC_REPORT_CRASH, false,
+			"exclaves lock not supported");
+	return false;
+#endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+}
+
+MALLOC_ALWAYS_INLINE
+static inline void
+_malloc_lock_unlock(_malloc_lock_s *lock) {
+#if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+# if MALLOC_HAS_OS_LOCK
+	os_unfair_lock_unlock(lock);
+# else
+	if (pthread_mutex_unlock(lock)) {
+		malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+				"Failed to release lock %p!\n", lock);
+	}
+# endif // MALLOC_HAS_OS_LOCK
+#else
+	malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+			"exclaves lock not supported");
+#endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+}
+
+MALLOC_ALWAYS_INLINE
+static inline void
+_malloc_lock_assert_owner(_malloc_lock_s *lock) {
+#if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+# if MALLOC_HAS_OS_LOCK
+	os_unfair_lock_assert_owner(lock);
+# endif // MALLOC_HAS_OS_LOCK
+#else
+	malloc_zone_error(MALLOC_ABORT_ON_ERROR, false,
+			"exclaves lock not supported");
+#endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
+}
+
+#endif // __LOCKING_H