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diff --git a/clang-r353983/include/llvm/Support/RWMutex.h b/clang-r353983/include/llvm/Support/RWMutex.h
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+++ b/clang-r353983/include/llvm/Support/RWMutex.h
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+//===- RWMutex.h - Reader/Writer Mutual Exclusion Lock ----------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the llvm::sys::RWMutex class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_RWMUTEX_H
+#define LLVM_SUPPORT_RWMUTEX_H
+
+#include "llvm/Config/llvm-config.h"
+#include "llvm/Support/Threading.h"
+#include <cassert>
+
+namespace llvm {
+namespace sys {
+
+    /// Platform agnostic RWMutex class.
+    class RWMutexImpl
+    {
+    /// @name Constructors
+    /// @{
+    public:
+
+      /// Initializes the lock but doesn't acquire it.
+      /// Default Constructor.
+      explicit RWMutexImpl();
+
+    /// @}
+    /// @name Do Not Implement
+    /// @{
+      RWMutexImpl(const RWMutexImpl & original) = delete;
+      RWMutexImpl &operator=(const RWMutexImpl &) = delete;
+    /// @}
+
+      /// Releases and removes the lock
+      /// Destructor
+      ~RWMutexImpl();
+
+    /// @}
+    /// @name Methods
+    /// @{
+    public:
+
+      /// Attempts to unconditionally acquire the lock in reader mode. If the
+      /// lock is held by a writer, this method will wait until it can acquire
+      /// the lock.
+      /// @returns false if any kind of error occurs, true otherwise.
+      /// Unconditionally acquire the lock in reader mode.
+      bool reader_acquire();
+
+      /// Attempts to release the lock in reader mode.
+      /// @returns false if any kind of error occurs, true otherwise.
+      /// Unconditionally release the lock in reader mode.
+      bool reader_release();
+
+      /// Attempts to unconditionally acquire the lock in reader mode. If the
+      /// lock is held by any readers, this method will wait until it can
+      /// acquire the lock.
+      /// @returns false if any kind of error occurs, true otherwise.
+      /// Unconditionally acquire the lock in writer mode.
+      bool writer_acquire();
+
+      /// Attempts to release the lock in writer mode.
+      /// @returns false if any kind of error occurs, true otherwise.
+      /// Unconditionally release the lock in write mode.
+      bool writer_release();
+
+    //@}
+    /// @name Platform Dependent Data
+    /// @{
+    private:
+#if defined(LLVM_ENABLE_THREADS) && LLVM_ENABLE_THREADS != 0
+      void* data_ = nullptr; ///< We don't know what the data will be
+#endif
+    };
+
+    /// SmartMutex - An R/W mutex with a compile time constant parameter that
+    /// indicates whether this mutex should become a no-op when we're not
+    /// running in multithreaded mode.
+    template<bool mt_only>
+    class SmartRWMutex {
+      RWMutexImpl impl;
+      unsigned readers = 0;
+      unsigned writers = 0;
+
+    public:
+      explicit SmartRWMutex() = default;
+      SmartRWMutex(const SmartRWMutex<mt_only> & original) = delete;
+      SmartRWMutex<mt_only> &operator=(const SmartRWMutex<mt_only> &) = delete;
+
+      bool lock_shared() {
+        if (!mt_only || llvm_is_multithreaded())
+          return impl.reader_acquire();
+
+        // Single-threaded debugging code.  This would be racy in multithreaded
+        // mode, but provides not sanity checks in single threaded mode.
+        ++readers;
+        return true;
+      }
+
+      bool unlock_shared() {
+        if (!mt_only || llvm_is_multithreaded())
+          return impl.reader_release();
+
+        // Single-threaded debugging code.  This would be racy in multithreaded
+        // mode, but provides not sanity checks in single threaded mode.
+        assert(readers > 0 && "Reader lock not acquired before release!");
+        --readers;
+        return true;
+      }
+
+      bool lock() {
+        if (!mt_only || llvm_is_multithreaded())
+          return impl.writer_acquire();
+
+        // Single-threaded debugging code.  This would be racy in multithreaded
+        // mode, but provides not sanity checks in single threaded mode.
+        assert(writers == 0 && "Writer lock already acquired!");
+        ++writers;
+        return true;
+      }
+
+      bool unlock() {
+        if (!mt_only || llvm_is_multithreaded())
+          return impl.writer_release();
+
+        // Single-threaded debugging code.  This would be racy in multithreaded
+        // mode, but provides not sanity checks in single threaded mode.
+        assert(writers == 1 && "Writer lock not acquired before release!");
+        --writers;
+        return true;
+      }
+    };
+
+    typedef SmartRWMutex<false> RWMutex;
+
+    /// ScopedReader - RAII acquisition of a reader lock
+    template<bool mt_only>
+    struct SmartScopedReader {
+      SmartRWMutex<mt_only>& mutex;
+
+      explicit SmartScopedReader(SmartRWMutex<mt_only>& m) : mutex(m) {
+        mutex.lock_shared();
+      }
+
+      ~SmartScopedReader() {
+        mutex.unlock_shared();
+      }
+    };
+
+    typedef SmartScopedReader<false> ScopedReader;
+
+    /// ScopedWriter - RAII acquisition of a writer lock
+    template<bool mt_only>
+    struct SmartScopedWriter {
+      SmartRWMutex<mt_only>& mutex;
+
+      explicit SmartScopedWriter(SmartRWMutex<mt_only>& m) : mutex(m) {
+        mutex.lock();
+      }
+
+      ~SmartScopedWriter() {
+        mutex.unlock();
+      }
+    };
+
+    typedef SmartScopedWriter<false> ScopedWriter;
+
+} // end namespace sys
+} // end namespace llvm
+
+#endif // LLVM_SUPPORT_RWMUTEX_H