diff --git a/compiler-rt/lib/gwp_asan/CMakeLists.txt b/compiler-rt/lib/gwp_asan/CMakeLists.txt
--- a/compiler-rt/lib/gwp_asan/CMakeLists.txt
+++ b/compiler-rt/lib/gwp_asan/CMakeLists.txt
@@ -7,6 +7,8 @@
 )
 
 set(GWP_ASAN_HEADERS
+  definitions.h
+  mutex.h
   random.h
 )
 
diff --git a/compiler-rt/lib/gwp_asan/definitions.h b/compiler-rt/lib/gwp_asan/definitions.h
new file mode 100644
--- /dev/null
+++ b/compiler-rt/lib/gwp_asan/definitions.h
@@ -0,0 +1,27 @@
+//===-- gwp_asan_definitions.h ----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef GWP_ASAN_DEFINITIONS_H_
+#define GWP_ASAN_DEFINITIONS_H_
+
+#ifdef LIKELY
+# undef LIKELY
+#endif // defined(LIKELY)
+#define LIKELY(X) __builtin_expect(!!(X), 1)
+
+#ifdef UNLIKELY
+# undef UNLIKELY
+#endif // defined(UNLIKELY)
+#define UNLIKELY(X) __builtin_expect(!!(X), 0)
+
+#ifdef ALWAYS_INLINE
+# undef ALWAYS_INLINE
+#endif // defined(ALWAYS_INLINE)
+#define ALWAYS_INLINE inline __attribute__((always_inline))
+
+#endif // GWP_ASAN_DEFINITIONS_H_
diff --git a/compiler-rt/lib/gwp_asan/mutex.h b/compiler-rt/lib/gwp_asan/mutex.h
new file mode 100644
--- /dev/null
+++ b/compiler-rt/lib/gwp_asan/mutex.h
@@ -0,0 +1,94 @@
+//===-- mutex.h -------------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// TODO(hctim): Move this implementation and Scudo's implementation into a
+// unified base implementation. We shouldn't need to have separate
+// implementations for this.
+
+#ifndef GWP_ASAN_MUTEX_H_
+#define GWP_ASAN_MUTEX_H_
+
+#include "gwp_asan/definitions.h"
+
+#include <cstdint>
+
+#ifdef __unix__
+#include <sched.h>
+#endif // defined(__unix__)
+
+namespace gwp_asan {
+class Mutex {
+public:
+  void lock();
+  bool tryLock();
+  void unlock();
+
+private:
+  void yieldProcessor(uint8_t Count);
+  void yieldPlatform();
+
+  void lockSlow();
+
+  bool Locked = false;
+};
+
+class ScopedLock {
+public:
+  explicit ScopedLock(Mutex *Mx) : Mu(Mx) { Mu->lock(); }
+  ~ScopedLock() { Mu->unlock(); }
+
+private:
+  Mutex *Mu;
+};
+
+ALWAYS_INLINE void Mutex::lock() {
+  if (tryLock())
+    return;
+  lockSlow();
+}
+
+ALWAYS_INLINE bool Mutex::tryLock() {
+  return !__atomic_exchange_n(&Locked, true, __ATOMIC_ACQUIRE);
+}
+
+ALWAYS_INLINE void Mutex::unlock() {
+  __atomic_store_n(&Locked, false, __ATOMIC_RELEASE);
+}
+
+ALWAYS_INLINE void Mutex::yieldProcessor(uint8_t Count) {
+#if defined(__i386__) || defined(__x86_64__)
+  asm volatile("" ::: "memory");
+  for (uint8_t i = 0; i < Count; ++i)
+    asm volatile("pause");
+#elif defined(__aarch64__) || defined(__arm__)
+  asm volatile("" ::: "memory");
+  for (uint8_t i = 0; i < Count; ++i)
+    asm volatile("yield");
+#endif
+  asm volatile("" ::: "memory");
+}
+
+ALWAYS_INLINE void Mutex::lockSlow() {
+  for (uint32_t i = 0;; ++i) {
+    if (i < 10)
+      yieldProcessor(10);
+    else
+      yieldPlatform();
+
+    if (!__atomic_load_n(&Locked, __ATOMIC_RELAXED) && tryLock())
+      return;
+  }
+}
+
+#ifdef __unix__
+ALWAYS_INLINE void Mutex::yieldPlatform() { sched_yield(); }
+#endif // defined(__unix__)
+
+} // namespace gwp_asan
+
+#endif // GWP_ASAN_MUTEX_H_