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diff --git a/clang-r353983e/include/llvm/ExecutionEngine/Orc/ThreadSafeModule.h b/clang-r353983e/include/llvm/ExecutionEngine/Orc/ThreadSafeModule.h
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index 00000000..57875003
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+++ b/clang-r353983e/include/llvm/ExecutionEngine/Orc/ThreadSafeModule.h
@@ -0,0 +1,162 @@
+//===----------- ThreadSafeModule.h -- Layer interfaces ---------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Thread safe wrappers and utilities for Module and LLVMContext.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_ORC_THREADSAFEMODULEWRAPPER_H
+#define LLVM_EXECUTIONENGINE_ORC_THREADSAFEMODULEWRAPPER_H
+
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/Compiler.h"
+
+#include <functional>
+#include <memory>
+#include <mutex>
+
+namespace llvm {
+namespace orc {
+
+/// An LLVMContext together with an associated mutex that can be used to lock
+/// the context to prevent concurrent access by other threads.
+class ThreadSafeContext {
+private:
+  struct State {
+    State(std::unique_ptr<LLVMContext> Ctx) : Ctx(std::move(Ctx)) {}
+
+    std::unique_ptr<LLVMContext> Ctx;
+    std::recursive_mutex Mutex;
+  };
+
+public:
+  // RAII based lock for ThreadSafeContext.
+  class LLVM_NODISCARD Lock {
+  private:
+    using UnderlyingLock = std::lock_guard<std::recursive_mutex>;
+
+  public:
+    Lock(std::shared_ptr<State> S)
+        : S(std::move(S)),
+          L(llvm::make_unique<UnderlyingLock>(this->S->Mutex)) {}
+
+  private:
+    std::shared_ptr<State> S;
+    std::unique_ptr<UnderlyingLock> L;
+  };
+
+  /// Construct a null context.
+  ThreadSafeContext() = default;
+
+  /// Construct a ThreadSafeContext from the given LLVMContext.
+  ThreadSafeContext(std::unique_ptr<LLVMContext> NewCtx)
+      : S(std::make_shared<State>(std::move(NewCtx))) {
+    assert(S->Ctx != nullptr &&
+           "Can not construct a ThreadSafeContext from a nullptr");
+  }
+
+  /// Returns a pointer to the LLVMContext that was used to construct this
+  /// instance, or null if the instance was default constructed.
+  LLVMContext *getContext() { return S ? S->Ctx.get() : nullptr; }
+
+  /// Returns a pointer to the LLVMContext that was used to construct this
+  /// instance, or null if the instance was default constructed.
+  const LLVMContext *getContext() const { return S ? S->Ctx.get() : nullptr; }
+
+  Lock getLock() {
+    assert(S && "Can not lock an empty ThreadSafeContext");
+    return Lock(S);
+  }
+
+private:
+  std::shared_ptr<State> S;
+};
+
+/// An LLVM Module together with a shared ThreadSafeContext.
+class ThreadSafeModule {
+public:
+  /// Default construct a ThreadSafeModule. This results in a null module and
+  /// null context.
+  ThreadSafeModule() = default;
+
+  ThreadSafeModule(ThreadSafeModule &&Other) = default;
+
+  ThreadSafeModule &operator=(ThreadSafeModule &&Other) {
+    // We have to explicitly define this move operator to copy the fields in
+    // reverse order (i.e. module first) to ensure the dependencies are
+    // protected: The old module that is being overwritten must be destroyed
+    // *before* the context that it depends on.
+    // We also need to lock the context to make sure the module tear-down
+    // does not overlap any other work on the context.
+    if (M) {
+      auto L = getContextLock();
+      M = nullptr;
+    }
+    M = std::move(Other.M);
+    TSCtx = std::move(Other.TSCtx);
+    return *this;
+  }
+
+  /// Construct a ThreadSafeModule from a unique_ptr<Module> and a
+  /// unique_ptr<LLVMContext>. This creates a new ThreadSafeContext from the
+  /// given context.
+  ThreadSafeModule(std::unique_ptr<Module> M, std::unique_ptr<LLVMContext> Ctx)
+      : M(std::move(M)), TSCtx(std::move(Ctx)) {}
+
+  /// Construct a ThreadSafeModule from a unique_ptr<Module> and an
+  /// existing ThreadSafeContext.
+  ThreadSafeModule(std::unique_ptr<Module> M, ThreadSafeContext TSCtx)
+      : M(std::move(M)), TSCtx(std::move(TSCtx)) {}
+
+  ~ThreadSafeModule() {
+    // We need to lock the context while we destruct the module.
+    if (M) {
+      auto L = getContextLock();
+      M = nullptr;
+    }
+  }
+
+  /// Get the module wrapped by this ThreadSafeModule.
+  Module *getModule() { return M.get(); }
+
+  /// Get the module wrapped by this ThreadSafeModule.
+  const Module *getModule() const { return M.get(); }
+
+  /// Take out a lock on the ThreadSafeContext for this module.
+  ThreadSafeContext::Lock getContextLock() { return TSCtx.getLock(); }
+
+  /// Boolean conversion: This ThreadSafeModule will evaluate to true if it
+  /// wraps a non-null module.
+  explicit operator bool() {
+    if (M) {
+      assert(TSCtx.getContext() &&
+             "Non-null module must have non-null context");
+      return true;
+    }
+    return false;
+  }
+
+private:
+  std::unique_ptr<Module> M;
+  ThreadSafeContext TSCtx;
+};
+
+using GVPredicate = std::function<bool(const GlobalValue &)>;
+using GVModifier = std::function<void(GlobalValue &)>;
+
+/// Clones the given module on to a new context.
+ThreadSafeModule
+cloneToNewContext(ThreadSafeModule &TSMW,
+                  GVPredicate ShouldCloneDef = GVPredicate(),
+                  GVModifier UpdateClonedDefSource = GVModifier());
+
+} // End namespace orc
+} // End namespace llvm
+
+#endif // LLVM_EXECUTIONENGINE_ORC_THREADSAFEMODULEWRAPPER_H