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diff --git a/contrib/llvm-project/libcxx/include/__utility/transaction.h b/contrib/llvm-project/libcxx/include/__utility/transaction.h
new file mode 100644
index 000000000000..87e51c0b198e
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+++ b/contrib/llvm-project/libcxx/include/__utility/transaction.h
@@ -0,0 +1,91 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 _LIBCPP___UTILITY_TRANSACTION_H
+#define _LIBCPP___UTILITY_TRANSACTION_H
+
+#include <__config>
+#include <__utility/exchange.h>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// __transaction is a helper class for writing code with the strong exception guarantee.
+//
+// When writing code that can throw an exception, one can store rollback instructions in a
+// transaction so that if an exception is thrown at any point during the lifetime of the
+// transaction, it will be rolled back automatically. When the transaction is done, one
+// must mark it as being complete so it isn't rolled back when the transaction is destroyed.
+//
+// Transactions are not default constructible, they can't be copied or assigned to, but
+// they can be moved around for convenience.
+//
+// __transaction can help greatly simplify code that would normally be cluttered by
+// `#if _LIBCPP_NO_EXCEPTIONS`. For example:
+//
+//    template <class Iterator, class Size, class OutputIterator>
+//    Iterator uninitialized_copy_n(Iterator iter, Size n, OutputIterator out) {
+//        typedef typename iterator_traits<Iterator>::value_type value_type;
+//        __transaction transaction([start=out, &out] {
+//            std::destroy(start, out);
+//        });
+//
+//        for (; n > 0; ++iter, ++out, --n) {
+//            ::new ((void*)std::addressof(*out)) value_type(*iter);
+//        }
+//        transaction.__complete();
+//        return out;
+//    }
+//
+template <class _Rollback>
+struct __transaction {
+    __transaction() = delete;
+
+    _LIBCPP_HIDE_FROM_ABI
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit __transaction(_Rollback __rollback)
+        : __rollback_(_VSTD::move(__rollback))
+        , __completed_(false)
+    { }
+
+    _LIBCPP_HIDE_FROM_ABI
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 __transaction(__transaction&& __other)
+        _NOEXCEPT_(is_nothrow_move_constructible<_Rollback>::value)
+        : __rollback_(_VSTD::move(__other.__rollback_))
+        , __completed_(__other.__completed_)
+    {
+        __other.__completed_ = true;
+    }
+
+    __transaction(__transaction const&) = delete;
+    __transaction& operator=(__transaction const&) = delete;
+    __transaction& operator=(__transaction&&) = delete;
+
+    _LIBCPP_HIDE_FROM_ABI
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void __complete() _NOEXCEPT {
+        __completed_ = true;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 ~__transaction() {
+        if (!__completed_)
+            __rollback_();
+    }
+
+private:
+    _Rollback __rollback_;
+    bool __completed_;
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_TRANSACTION_H