From a34680a33eb1caa5e224a9432e9f3e643824dc2d Mon Sep 17 00:00:00 2001
From: Chris Bieneman <chris.bieneman@me.com>
Date: Wed, 9 Oct 2019 14:27:52 -0700
Subject: Break out OrcError and RPC

Summary:
When createing an ORC remote JIT target the current library split forces the target process to link large portions of LLVM (Core, Execution Engine, JITLink, Object, MC, Passes, RuntimeDyld, Support, Target, and TransformUtils). This occurs because the ORC RPC interfaces rely on the static globals the ORC Error types require, which starts a cycle of pulling in more and more.

This patch breaks the ORC RPC Error implementations out into an "OrcError" library which only depends on LLVM Support. It also pulls the ORC RPC headers into their own subdirectory.

With this patch code can include the Orc/RPC/*.h headers and will only incur link dependencies on LLVMOrcError and LLVMSupport.

Reviewers: lhames

Reviewed By: lhames

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68732
---
 .../BuildingAJIT/Chapter5/RemoteJITUtils.h         |    2 +-
 .../ExecutionEngine/Orc/OrcRemoteTargetRPCAPI.h    |    4 +-
 .../ExecutionEngine/Orc/RPC/RPCSerialization.h     |  703 ++++++++
 .../llvm/ExecutionEngine/Orc/RPC/RPCUtils.h        | 1690 ++++++++++++++++++++
 .../llvm/ExecutionEngine/Orc/RPC/RawByteChannel.h  |  184 +++
 .../llvm/ExecutionEngine/Orc/RPCSerialization.h    |  703 --------
 llvm/include/llvm/ExecutionEngine/Orc/RPCUtils.h   | 1690 --------------------
 .../llvm/ExecutionEngine/Orc/RawByteChannel.h      |  184 ---
 llvm/lib/ExecutionEngine/CMakeLists.txt            |    1 +
 llvm/lib/ExecutionEngine/LLVMBuild.txt             |    2 +-
 llvm/lib/ExecutionEngine/Orc/CMakeLists.txt        |    2 -
 llvm/lib/ExecutionEngine/Orc/LLVMBuild.txt         |    4 +-
 llvm/lib/ExecutionEngine/Orc/OrcError.cpp          |  115 --
 llvm/lib/ExecutionEngine/Orc/RPCUtils.cpp          |   54 -
 llvm/lib/ExecutionEngine/OrcError/CMakeLists.txt   |    6 +
 llvm/lib/ExecutionEngine/OrcError/LLVMBuild.txt    |   21 +
 llvm/lib/ExecutionEngine/OrcError/OrcError.cpp     |  115 ++
 llvm/lib/ExecutionEngine/OrcError/RPCError.cpp     |   54 +
 llvm/tools/lli/RemoteJITUtils.h                    |    2 +-
 llvm/unittests/ExecutionEngine/Orc/QueueChannel.h  |    2 +-
 .../unittests/ExecutionEngine/Orc/RPCUtilsTest.cpp |    2 +-
 21 files changed, 2783 insertions(+), 2757 deletions(-)
 create mode 100644 llvm/include/llvm/ExecutionEngine/Orc/RPC/RPCSerialization.h
 create mode 100644 llvm/include/llvm/ExecutionEngine/Orc/RPC/RPCUtils.h
 create mode 100644 llvm/include/llvm/ExecutionEngine/Orc/RPC/RawByteChannel.h
 delete mode 100644 llvm/include/llvm/ExecutionEngine/Orc/RPCSerialization.h
 delete mode 100644 llvm/include/llvm/ExecutionEngine/Orc/RPCUtils.h
 delete mode 100644 llvm/include/llvm/ExecutionEngine/Orc/RawByteChannel.h
 delete mode 100644 llvm/lib/ExecutionEngine/Orc/OrcError.cpp
 delete mode 100644 llvm/lib/ExecutionEngine/Orc/RPCUtils.cpp
 create mode 100644 llvm/lib/ExecutionEngine/OrcError/CMakeLists.txt
 create mode 100644 llvm/lib/ExecutionEngine/OrcError/LLVMBuild.txt
 create mode 100644 llvm/lib/ExecutionEngine/OrcError/OrcError.cpp
 create mode 100644 llvm/lib/ExecutionEngine/OrcError/RPCError.cpp

diff --git a/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter5/RemoteJITUtils.h b/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter5/RemoteJITUtils.h
index 14a2815bc02..c7d15bb8dd9 100644
--- a/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter5/RemoteJITUtils.h
+++ b/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter5/RemoteJITUtils.h
@@ -13,7 +13,7 @@
 #ifndef LLVM_TOOLS_LLI_REMOTEJITUTILS_H
 #define LLVM_TOOLS_LLI_REMOTEJITUTILS_H
 
-#include "llvm/ExecutionEngine/Orc/RawByteChannel.h"
+#include "llvm/ExecutionEngine/Orc/RPC/RawByteChannel.h"
 #include "llvm/Support/Error.h"
 #include <cassert>
 #include <cerrno>
diff --git a/llvm/include/llvm/ExecutionEngine/Orc/OrcRemoteTargetRPCAPI.h b/llvm/include/llvm/ExecutionEngine/Orc/OrcRemoteTargetRPCAPI.h
index e7b598d8f81..3ff5a5f6e90 100644
--- a/llvm/include/llvm/ExecutionEngine/Orc/OrcRemoteTargetRPCAPI.h
+++ b/llvm/include/llvm/ExecutionEngine/Orc/OrcRemoteTargetRPCAPI.h
@@ -16,8 +16,8 @@
 #define LLVM_EXECUTIONENGINE_ORC_ORCREMOTETARGETRPCAPI_H
 
 #include "llvm/ExecutionEngine/JITSymbol.h"
-#include "llvm/ExecutionEngine/Orc/RPCUtils.h"
-#include "llvm/ExecutionEngine/Orc/RawByteChannel.h"
+#include "llvm/ExecutionEngine/Orc/RPC/RPCUtils.h"
+#include "llvm/ExecutionEngine/Orc/RPC/RawByteChannel.h"
 
 namespace llvm {
 namespace orc {
diff --git a/llvm/include/llvm/ExecutionEngine/Orc/RPC/RPCSerialization.h b/llvm/include/llvm/ExecutionEngine/Orc/RPC/RPCSerialization.h
new file mode 100644
index 00000000000..9c69a84f4c6
--- /dev/null
+++ b/llvm/include/llvm/ExecutionEngine/Orc/RPC/RPCSerialization.h
@@ -0,0 +1,703 @@
+//===- llvm/ExecutionEngine/Orc/RPC/RPCSerialization.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 LLVM_EXECUTIONENGINE_ORC_RPCSERIALIZATION_H
+#define LLVM_EXECUTIONENGINE_ORC_RPCSERIALIZATION_H
+
+#include "llvm/ExecutionEngine/Orc/OrcError.h"
+#include "llvm/Support/thread.h"
+#include <map>
+#include <mutex>
+#include <set>
+#include <sstream>
+#include <string>
+#include <vector>
+
+namespace llvm {
+namespace orc {
+namespace rpc {
+
+template <typename T>
+class RPCTypeName;
+
+/// TypeNameSequence is a utility for rendering sequences of types to a string
+/// by rendering each type, separated by ", ".
+template <typename... ArgTs> class RPCTypeNameSequence {};
+
+/// Render an empty TypeNameSequence to an ostream.
+template <typename OStream>
+OStream &operator<<(OStream &OS, const RPCTypeNameSequence<> &V) {
+  return OS;
+}
+
+/// Render a TypeNameSequence of a single type to an ostream.
+template <typename OStream, typename ArgT>
+OStream &operator<<(OStream &OS, const RPCTypeNameSequence<ArgT> &V) {
+  OS << RPCTypeName<ArgT>::getName();
+  return OS;
+}
+
+/// Render a TypeNameSequence of more than one type to an ostream.
+template <typename OStream, typename ArgT1, typename ArgT2, typename... ArgTs>
+OStream&
+operator<<(OStream &OS, const RPCTypeNameSequence<ArgT1, ArgT2, ArgTs...> &V) {
+  OS << RPCTypeName<ArgT1>::getName() << ", "
+     << RPCTypeNameSequence<ArgT2, ArgTs...>();
+  return OS;
+}
+
+template <>
+class RPCTypeName<void> {
+public:
+  static const char* getName() { return "void"; }
+};
+
+template <>
+class RPCTypeName<int8_t> {
+public:
+  static const char* getName() { return "int8_t"; }
+};
+
+template <>
+class RPCTypeName<uint8_t> {
+public:
+  static const char* getName() { return "uint8_t"; }
+};
+
+template <>
+class RPCTypeName<int16_t> {
+public:
+  static const char* getName() { return "int16_t"; }
+};
+
+template <>
+class RPCTypeName<uint16_t> {
+public:
+  static const char* getName() { return "uint16_t"; }
+};
+
+template <>
+class RPCTypeName<int32_t> {
+public:
+  static const char* getName() { return "int32_t"; }
+};
+
+template <>
+class RPCTypeName<uint32_t> {
+public:
+  static const char* getName() { return "uint32_t"; }
+};
+
+template <>
+class RPCTypeName<int64_t> {
+public:
+  static const char* getName() { return "int64_t"; }
+};
+
+template <>
+class RPCTypeName<uint64_t> {
+public:
+  static const char* getName() { return "uint64_t"; }
+};
+
+template <>
+class RPCTypeName<bool> {
+public:
+  static const char* getName() { return "bool"; }
+};
+
+template <>
+class RPCTypeName<std::string> {
+public:
+  static const char* getName() { return "std::string"; }
+};
+
+template <>
+class RPCTypeName<Error> {
+public:
+  static const char* getName() { return "Error"; }
+};
+
+template <typename T>
+class RPCTypeName<Expected<T>> {
+public:
+  static const char* getName() {
+    static std::string Name = [] {
+      std::string Name;
+      raw_string_ostream(Name) << "Expected<"
+                               << RPCTypeNameSequence<T>()
+                               << ">";
+      return Name;
+    }();
+    return Name.data();
+  }
+};
+
+template <typename T1, typename T2>
+class RPCTypeName<std::pair<T1, T2>> {
+public:
+  static const char* getName() {
+    static std::string Name = [] {
+      std::string Name;
+      raw_string_ostream(Name) << "std::pair<" << RPCTypeNameSequence<T1, T2>()
+                               << ">";
+      return Name;
+    }();
+    return Name.data();
+  }
+};
+
+template <typename... ArgTs>
+class RPCTypeName<std::tuple<ArgTs...>> {
+public:
+  static const char* getName() {
+    static std::string Name = [] {
+      std::string Name;
+      raw_string_ostream(Name) << "std::tuple<"
+                               << RPCTypeNameSequence<ArgTs...>() << ">";
+      return Name;
+    }();
+    return Name.data();
+  }
+};
+
+template <typename T>
+class RPCTypeName<std::vector<T>> {
+public:
+  static const char*getName() {
+    static std::string Name = [] {
+      std::string Name;
+      raw_string_ostream(Name) << "std::vector<" << RPCTypeName<T>::getName()
+                               << ">";
+      return Name;
+    }();
+    return Name.data();
+  }
+};
+
+template <typename T> class RPCTypeName<std::set<T>> {
+public:
+  static const char *getName() {
+    static std::string Name = [] {
+      std::string Name;
+      raw_string_ostream(Name)
+          << "std::set<" << RPCTypeName<T>::getName() << ">";
+      return Name;
+    }();
+    return Name.data();
+  }
+};
+
+template <typename K, typename V> class RPCTypeName<std::map<K, V>> {
+public:
+  static const char *getName() {
+    static std::string Name = [] {
+      std::string Name;
+      raw_string_ostream(Name)
+          << "std::map<" << RPCTypeNameSequence<K, V>() << ">";
+      return Name;
+    }();
+    return Name.data();
+  }
+};
+
+/// The SerializationTraits<ChannelT, T> class describes how to serialize and
+/// deserialize an instance of type T to/from an abstract channel of type
+/// ChannelT. It also provides a representation of the type's name via the
+/// getName method.
+///
+/// Specializations of this class should provide the following functions:
+///
+///   @code{.cpp}
+///
+///   static const char* getName();
+///   static Error serialize(ChannelT&, const T&);
+///   static Error deserialize(ChannelT&, T&);
+///
+///   @endcode
+///
+/// The third argument of SerializationTraits is intended to support SFINAE.
+/// E.g.:
+///
+///   @code{.cpp}
+///
+///   class MyVirtualChannel { ... };
+///
+///   template <DerivedChannelT>
+///   class SerializationTraits<DerivedChannelT, bool,
+///         typename std::enable_if<
+///           std::is_base_of<VirtChannel, DerivedChannel>::value
+///         >::type> {
+///   public:
+///     static const char* getName() { ... };
+///   }
+///
+///   @endcode
+template <typename ChannelT, typename WireType,
+          typename ConcreteType = WireType, typename = void>
+class SerializationTraits;
+
+template <typename ChannelT>
+class SequenceTraits {
+public:
+  static Error emitSeparator(ChannelT &C) { return Error::success(); }
+  static Error consumeSeparator(ChannelT &C) { return Error::success(); }
+};
+
+/// Utility class for serializing sequences of values of varying types.
+/// Specializations of this class contain 'serialize' and 'deserialize' methods
+/// for the given channel. The ArgTs... list will determine the "over-the-wire"
+/// types to be serialized. The serialize and deserialize methods take a list
+/// CArgTs... ("caller arg types") which must be the same length as ArgTs...,
+/// but may be different types from ArgTs, provided that for each CArgT there
+/// is a SerializationTraits specialization
+/// SerializeTraits<ChannelT, ArgT, CArgT> with methods that can serialize the
+/// caller argument to over-the-wire value.
+template <typename ChannelT, typename... ArgTs>
+class SequenceSerialization;
+
+template <typename ChannelT>
+class SequenceSerialization<ChannelT> {
+public:
+  static Error serialize(ChannelT &C) { return Error::success(); }
+  static Error deserialize(ChannelT &C) { return Error::success(); }
+};
+
+template <typename ChannelT, typename ArgT>
+class SequenceSerialization<ChannelT, ArgT> {
+public:
+
+  template <typename CArgT>
+  static Error serialize(ChannelT &C, CArgT &&CArg) {
+    return SerializationTraits<ChannelT, ArgT,
+                               typename std::decay<CArgT>::type>::
+             serialize(C, std::forward<CArgT>(CArg));
+  }
+
+  template <typename CArgT>
+  static Error deserialize(ChannelT &C, CArgT &CArg) {
+    return SerializationTraits<ChannelT, ArgT, CArgT>::deserialize(C, CArg);
+  }
+};
+
+template <typename ChannelT, typename ArgT, typename... ArgTs>
+class SequenceSerialization<ChannelT, ArgT, ArgTs...> {
+public:
+
+  template <typename CArgT, typename... CArgTs>
+  static Error serialize(ChannelT &C, CArgT &&CArg,
+                         CArgTs &&... CArgs) {
+    if (auto Err =
+        SerializationTraits<ChannelT, ArgT, typename std::decay<CArgT>::type>::
+          serialize(C, std::forward<CArgT>(CArg)))
+      return Err;
+    if (auto Err = SequenceTraits<ChannelT>::emitSeparator(C))
+      return Err;
+    return SequenceSerialization<ChannelT, ArgTs...>::
+             serialize(C, std::forward<CArgTs>(CArgs)...);
+  }
+
+  template <typename CArgT, typename... CArgTs>
+  static Error deserialize(ChannelT &C, CArgT &CArg,
+                           CArgTs &... CArgs) {
+    if (auto Err =
+        SerializationTraits<ChannelT, ArgT, CArgT>::deserialize(C, CArg))
+      return Err;
+    if (auto Err = SequenceTraits<ChannelT>::consumeSeparator(C))
+      return Err;
+    return SequenceSerialization<ChannelT, ArgTs...>::deserialize(C, CArgs...);
+  }
+};
+
+template <typename ChannelT, typename... ArgTs>
+Error serializeSeq(ChannelT &C, ArgTs &&... Args) {
+  return SequenceSerialization<ChannelT, typename std::decay<ArgTs>::type...>::
+           serialize(C, std::forward<ArgTs>(Args)...);
+}
+
+template <typename ChannelT, typename... ArgTs>
+Error deserializeSeq(ChannelT &C, ArgTs &... Args) {
+  return SequenceSerialization<ChannelT, ArgTs...>::deserialize(C, Args...);
+}
+
+template <typename ChannelT>
+class SerializationTraits<ChannelT, Error> {
+public:
+
+  using WrappedErrorSerializer =
+    std::function<Error(ChannelT &C, const ErrorInfoBase&)>;
+
+  using WrappedErrorDeserializer =
+    std::function<Error(ChannelT &C, Error &Err)>;
+
+  template <typename ErrorInfoT, typename SerializeFtor,
+            typename DeserializeFtor>
+  static void registerErrorType(std::string Name, SerializeFtor Serialize,
+                                DeserializeFtor Deserialize) {
+    assert(!Name.empty() &&
+           "The empty string is reserved for the Success value");
+
+    const std::string *KeyName = nullptr;
+    {
+      // We're abusing the stability of std::map here: We take a reference to the
+      // key of the deserializers map to save us from duplicating the string in
+      // the serializer. This should be changed to use a stringpool if we switch
+      // to a map type that may move keys in memory.
+      std::lock_guard<std::recursive_mutex> Lock(DeserializersMutex);
+      auto I =
+        Deserializers.insert(Deserializers.begin(),
+                             std::make_pair(std::move(Name),
+                                            std::move(Deserialize)));
+      KeyName = &I->first;
+    }
+
+    {
+      assert(KeyName != nullptr && "No keyname pointer");
+      std::lock_guard<std::recursive_mutex> Lock(SerializersMutex);
+      Serializers[ErrorInfoT::classID()] =
+          [KeyName, Serialize = std::move(Serialize)](
+              ChannelT &C, const ErrorInfoBase &EIB) -> Error {
+        assert(EIB.dynamicClassID() == ErrorInfoT::classID() &&
+               "Serializer called for wrong error type");
+        if (auto Err = serializeSeq(C, *KeyName))
+          return Err;
+        return Serialize(C, static_cast<const ErrorInfoT &>(EIB));
+      };
+    }
+  }
+
+  static Error serialize(ChannelT &C, Error &&Err) {
+    std::lock_guard<std::recursive_mutex> Lock(SerializersMutex);
+
+    if (!Err)
+      return serializeSeq(C, std::string());
+
+    return handleErrors(std::move(Err),
+                        [&C](const ErrorInfoBase &EIB) {
+                          auto SI = Serializers.find(EIB.dynamicClassID());
+                          if (SI == Serializers.end())
+                            return serializeAsStringError(C, EIB);
+                          return (SI->second)(C, EIB);
+                        });
+  }
+
+  static Error deserialize(ChannelT &C, Error &Err) {
+    std::lock_guard<std::recursive_mutex> Lock(DeserializersMutex);
+
+    std::string Key;
+    if (auto Err = deserializeSeq(C, Key))
+      return Err;
+
+    if (Key.empty()) {
+      ErrorAsOutParameter EAO(&Err);
+      Err = Error::success();
+      return Error::success();
+    }
+
+    auto DI = Deserializers.find(Key);
+    assert(DI != Deserializers.end() && "No deserializer for error type");
+    return (DI->second)(C, Err);
+  }
+
+private:
+
+  static Error serializeAsStringError(ChannelT &C, const ErrorInfoBase &EIB) {
+    std::string ErrMsg;
+    {
+      raw_string_ostream ErrMsgStream(ErrMsg);
+      EIB.log(ErrMsgStream);
+    }
+    return serialize(C, make_error<StringError>(std::move(ErrMsg),
+                                                inconvertibleErrorCode()));
+  }
+
+  static std::recursive_mutex SerializersMutex;
+  static std::recursive_mutex DeserializersMutex;
+  static std::map<const void*, WrappedErrorSerializer> Serializers;
+  static std::map<std::string, WrappedErrorDeserializer> Deserializers;
+};
+
+template <typename ChannelT>
+std::recursive_mutex SerializationTraits<ChannelT, Error>::SerializersMutex;
+
+template <typename ChannelT>
+std::recursive_mutex SerializationTraits<ChannelT, Error>::DeserializersMutex;
+
+template <typename ChannelT>
+std::map<const void*,
+         typename SerializationTraits<ChannelT, Error>::WrappedErrorSerializer>
+SerializationTraits<ChannelT, Error>::Serializers;
+
+template <typename ChannelT>
+std::map<std::string,
+         typename SerializationTraits<ChannelT, Error>::WrappedErrorDeserializer>
+SerializationTraits<ChannelT, Error>::Deserializers;
+
+/// Registers a serializer and deserializer for the given error type on the
+/// given channel type.
+template <typename ChannelT, typename ErrorInfoT, typename SerializeFtor,
+          typename DeserializeFtor>
+void registerErrorSerialization(std::string Name, SerializeFtor &&Serialize,
+                                DeserializeFtor &&Deserialize) {
+  SerializationTraits<ChannelT, Error>::template registerErrorType<ErrorInfoT>(
+    std::move(Name),
+    std::forward<SerializeFtor>(Serialize),
+    std::forward<DeserializeFtor>(Deserialize));
+}
+
+/// Registers serialization/deserialization for StringError.
+template <typename ChannelT>
+void registerStringError() {
+  static bool AlreadyRegistered = false;
+  if (!AlreadyRegistered) {
+    registerErrorSerialization<ChannelT, StringError>(
+      "StringError",
+      [](ChannelT &C, const StringError &SE) {
+        return serializeSeq(C, SE.getMessage());
+      },
+      [](ChannelT &C, Error &Err) -> Error {
+        ErrorAsOutParameter EAO(&Err);
+        std::string Msg;
+        if (auto E2 = deserializeSeq(C, Msg))
+          return E2;
+        Err =
+          make_error<StringError>(std::move(Msg),
+                                  orcError(
+                                    OrcErrorCode::UnknownErrorCodeFromRemote));
+        return Error::success();
+      });
+    AlreadyRegistered = true;
+  }
+}
+
+/// SerializationTraits for Expected<T1> from an Expected<T2>.
+template <typename ChannelT, typename T1, typename T2>
+class SerializationTraits<ChannelT, Expected<T1>, Expected<T2>> {
+public:
+
+  static Error serialize(ChannelT &C, Expected<T2> &&ValOrErr) {
+    if (ValOrErr) {
+      if (auto Err = serializeSeq(C, true))
+        return Err;
+      return SerializationTraits<ChannelT, T1, T2>::serialize(C, *ValOrErr);
+    }
+    if (auto Err = serializeSeq(C, false))
+      return Err;
+    return serializeSeq(C, ValOrErr.takeError());
+  }
+
+  static Error deserialize(ChannelT &C, Expected<T2> &ValOrErr) {
+    ExpectedAsOutParameter<T2> EAO(&ValOrErr);
+    bool HasValue;
+    if (auto Err = deserializeSeq(C, HasValue))
+      return Err;
+    if (HasValue)
+      return SerializationTraits<ChannelT, T1, T2>::deserialize(C, *ValOrErr);
+    Error Err = Error::success();
+    if (auto E2 = deserializeSeq(C, Err))
+      return E2;
+    ValOrErr = std::move(Err);
+    return Error::success();
+  }
+};
+
+/// SerializationTraits for Expected<T1> from a T2.
+template <typename ChannelT, typename T1, typename T2>
+class SerializationTraits<ChannelT, Expected<T1>, T2> {
+public:
+
+  static Error serialize(ChannelT &C, T2 &&Val) {
+    return serializeSeq(C, Expected<T2>(std::forward<T2>(Val)));
+  }
+};
+
+/// SerializationTraits for Expected<T1> from an Error.
+template <typename ChannelT, typename T>
+class SerializationTraits<ChannelT, Expected<T>, Error> {
+public:
+
+  static Error serialize(ChannelT &C, Error &&Err) {
+    return serializeSeq(C, Expected<T>(std::move(Err)));
+  }
+};
+
+/// SerializationTraits default specialization for std::pair.
+template <typename ChannelT, typename T1, typename T2, typename T3, typename T4>
+class SerializationTraits<ChannelT, std::pair<T1, T2>, std::pair<T3, T4>> {
+public:
+  static Error serialize(ChannelT &C, const std::pair<T3, T4> &V) {
+    if (auto Err = SerializationTraits<ChannelT, T1, T3>::serialize(C, V.first))
+      return Err;
+    return SerializationTraits<ChannelT, T2, T4>::serialize(C, V.second);
+  }
+
+  static Error deserialize(ChannelT &C, std::pair<T3, T4> &V) {
+    if (auto Err =
+            SerializationTraits<ChannelT, T1, T3>::deserialize(C, V.first))
+      return Err;
+    return SerializationTraits<ChannelT, T2, T4>::deserialize(C, V.second);
+  }
+};
+
+/// SerializationTraits default specialization for std::tuple.
+template <typename ChannelT, typename... ArgTs>
+class SerializationTraits<ChannelT, std::tuple<ArgTs...>> {
+public:
+
+  /// RPC channel serialization for std::tuple.
+  static Error serialize(ChannelT &C, const std::tuple<ArgTs...> &V) {
+    return serializeTupleHelper(C, V, std::index_sequence_for<ArgTs...>());
+  }
+
+  /// RPC channel deserialization for std::tuple.
+  static Error deserialize(ChannelT &C, std::tuple<ArgTs...> &V) {
+    return deserializeTupleHelper(C, V, std::index_sequence_for<ArgTs...>());
+  }
+
+private:
+  // Serialization helper for std::tuple.
+  template <size_t... Is>
+  static Error serializeTupleHelper(ChannelT &C, const std::tuple<ArgTs...> &V,
+                                    std::index_sequence<Is...> _) {
+    return serializeSeq(C, std::get<Is>(V)...);
+  }
+
+  // Serialization helper for std::tuple.
+  template <size_t... Is>
+  static Error deserializeTupleHelper(ChannelT &C, std::tuple<ArgTs...> &V,
+                                      std::index_sequence<Is...> _) {
+    return deserializeSeq(C, std::get<Is>(V)...);
+  }
+};
+
+/// SerializationTraits default specialization for std::vector.
+template <typename ChannelT, typename T>
+class SerializationTraits<ChannelT, std::vector<T>> {
+public:
+
+  /// Serialize a std::vector<T> from std::vector<T>.
+  static Error serialize(ChannelT &C, const std::vector<T> &V) {
+    if (auto Err = serializeSeq(C, static_cast<uint64_t>(V.size())))
+      return Err;
+
+    for (const auto &E : V)
+      if (auto Err = serializeSeq(C, E))
+        return Err;
+
+    return Error::success();
+  }
+
+  /// Deserialize a std::vector<T> to a std::vector<T>.
+  static Error deserialize(ChannelT &C, std::vector<T> &V) {
+    assert(V.empty() &&
+           "Expected default-constructed vector to deserialize into");
+
+    uint64_t Count = 0;
+    if (auto Err = deserializeSeq(C, Count))
+      return Err;
+
+    V.resize(Count);
+    for (auto &E : V)
+      if (auto Err = deserializeSeq(C, E))
+        return Err;
+
+    return Error::success();
+  }
+};
+
+template <typename ChannelT, typename T, typename T2>
+class SerializationTraits<ChannelT, std::set<T>, std::set<T2>> {
+public:
+  /// Serialize a std::set<T> from std::set<T2>.
+  static Error serialize(ChannelT &C, const std::set<T2> &S) {
+    if (auto Err = serializeSeq(C, static_cast<uint64_t>(S.size())))
+      return Err;
+
+    for (const auto &E : S)
+      if (auto Err = SerializationTraits<ChannelT, T, T2>::serialize(C, E))
+        return Err;
+
+    return Error::success();
+  }
+
+  /// Deserialize a std::set<T> to a std::set<T>.
+  static Error deserialize(ChannelT &C, std::set<T2> &S) {
+    assert(S.empty() && "Expected default-constructed set to deserialize into");
+
+    uint64_t Count = 0;
+    if (auto Err = deserializeSeq(C, Count))
+      return Err;
+
+    while (Count-- != 0) {
+      T2 Val;
+      if (auto Err = SerializationTraits<ChannelT, T, T2>::deserialize(C, Val))
+        return Err;
+
+      auto Added = S.insert(Val).second;
+      if (!Added)
+        return make_error<StringError>("Duplicate element in deserialized set",
+                                       orcError(OrcErrorCode::UnknownORCError));
+    }
+
+    return Error::success();
+  }
+};
+
+template <typename ChannelT, typename K, typename V, typename K2, typename V2>
+class SerializationTraits<ChannelT, std::map<K, V>, std::map<K2, V2>> {
+public:
+  /// Serialize a std::map<K, V> from std::map<K2, V2>.
+  static Error serialize(ChannelT &C, const std::map<K2, V2> &M) {
+    if (auto Err = serializeSeq(C, static_cast<uint64_t>(M.size())))
+      return Err;
+
+    for (const auto &E : M) {
+      if (auto Err =
+              SerializationTraits<ChannelT, K, K2>::serialize(C, E.first))
+        return Err;
+      if (auto Err =
+              SerializationTraits<ChannelT, V, V2>::serialize(C, E.second))
+        return Err;
+    }
+
+    return Error::success();
+  }
+
+  /// Deserialize a std::map<K, V> to a std::map<K, V>.
+  static Error deserialize(ChannelT &C, std::map<K2, V2> &M) {
+    assert(M.empty() && "Expected default-constructed map to deserialize into");
+
+    uint64_t Count = 0;
+    if (auto Err = deserializeSeq(C, Count))
+      return Err;
+
+    while (Count-- != 0) {
+      std::pair<K2, V2> Val;
+      if (auto Err =
+              SerializationTraits<ChannelT, K, K2>::deserialize(C, Val.first))
+        return Err;
+
+      if (auto Err =
+              SerializationTraits<ChannelT, V, V2>::deserialize(C, Val.second))
+        return Err;
+
+      auto Added = M.insert(Val).second;
+      if (!Added)
+        return make_error<StringError>("Duplicate element in deserialized map",
+                                       orcError(OrcErrorCode::UnknownORCError));
+    }
+
+    return Error::success();
+  }
+};
+
+} // end namespace rpc
+} // end namespace orc
+} // end namespace llvm
+
+#endif // LLVM_EXECUTIONENGINE_ORC_RPCSERIALIZATION_H
diff --git a/llvm/include/llvm/ExecutionEngine/Orc/RPC/RPCUtils.h b/llvm/include/llvm/ExecutionEngine/Orc/RPC/RPCUtils.h
new file mode 100644
index 00000000000..ed09363dcec
--- /dev/null
+++ b/llvm/include/llvm/ExecutionEngine/Orc/RPC/RPCUtils.h
@@ -0,0 +1,1690 @@
+//===- RPCUtils.h - Utilities for building RPC APIs -------------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Utilities to support construction of simple RPC APIs.
+//
+// The RPC utilities aim for ease of use (minimal conceptual overhead) for C++
+// programmers, high performance, low memory overhead, and efficient use of the
+// communications channel.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_ORC_RPCUTILS_H
+#define LLVM_EXECUTIONENGINE_ORC_RPCUTILS_H
+
+#include <map>
+#include <thread>
+#include <vector>
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ExecutionEngine/Orc/OrcError.h"
+#include "llvm/ExecutionEngine/Orc/RPC/RPCSerialization.h"
+#include "llvm/Support/MSVCErrorWorkarounds.h"
+
+#include <future>
+
+namespace llvm {
+namespace orc {
+namespace rpc {
+
+/// Base class of all fatal RPC errors (those that necessarily result in the
+/// termination of the RPC session).
+class RPCFatalError : public ErrorInfo<RPCFatalError> {
+public:
+  static char ID;
+};
+
+/// RPCConnectionClosed is returned from RPC operations if the RPC connection
+/// has already been closed due to either an error or graceful disconnection.
+class ConnectionClosed : public ErrorInfo<ConnectionClosed> {
+public:
+  static char ID;
+  std::error_code convertToErrorCode() const override;
+  void log(raw_ostream &OS) const override;
+};
+
+/// BadFunctionCall is returned from handleOne when the remote makes a call with
+/// an unrecognized function id.
+///
+/// This error is fatal because Orc RPC needs to know how to parse a function
+/// call to know where the next call starts, and if it doesn't recognize the
+/// function id it cannot parse the call.
+template <typename FnIdT, typename SeqNoT>
+class BadFunctionCall
+  : public ErrorInfo<BadFunctionCall<FnIdT, SeqNoT>, RPCFatalError> {
+public:
+  static char ID;
+
+  BadFunctionCall(FnIdT FnId, SeqNoT SeqNo)
+      : FnId(std::move(FnId)), SeqNo(std::move(SeqNo)) {}
+
+  std::error_code convertToErrorCode() const override {
+    return orcError(OrcErrorCode::UnexpectedRPCCall);
+  }
+
+  void log(raw_ostream &OS) const override {
+    OS << "Call to invalid RPC function id '" << FnId << "' with "
+          "sequence number " << SeqNo;
+  }
+
+private:
+  FnIdT FnId;
+  SeqNoT SeqNo;
+};
+
+template <typename FnIdT, typename SeqNoT>
+char BadFunctionCall<FnIdT, SeqNoT>::ID = 0;
+
+/// InvalidSequenceNumberForResponse is returned from handleOne when a response
+/// call arrives with a sequence number that doesn't correspond to any in-flight
+/// function call.
+///
+/// This error is fatal because Orc RPC needs to know how to parse the rest of
+/// the response call to know where the next call starts, and if it doesn't have
+/// a result parser for this sequence number it can't do that.
+template <typename SeqNoT>
+class InvalidSequenceNumberForResponse
+    : public ErrorInfo<InvalidSequenceNumberForResponse<SeqNoT>, RPCFatalError> {
+public:
+  static char ID;
+
+  InvalidSequenceNumberForResponse(SeqNoT SeqNo)
+      : SeqNo(std::move(SeqNo)) {}
+
+  std::error_code convertToErrorCode() const override {
+    return orcError(OrcErrorCode::UnexpectedRPCCall);
+  };
+
+  void log(raw_ostream &OS) const override {
+    OS << "Response has unknown sequence number " << SeqNo;
+  }
+private:
+  SeqNoT SeqNo;
+};
+
+template <typename SeqNoT>
+char InvalidSequenceNumberForResponse<SeqNoT>::ID = 0;
+
+/// This non-fatal error will be passed to asynchronous result handlers in place
+/// of a result if the connection goes down before a result returns, or if the
+/// function to be called cannot be negotiated with the remote.
+class ResponseAbandoned : public ErrorInfo<ResponseAbandoned> {
+public:
+  static char ID;
+
+  std::error_code convertToErrorCode() const override;
+  void log(raw_ostream &OS) const override;
+};
+
+/// This error is returned if the remote does not have a handler installed for
+/// the given RPC function.
+class CouldNotNegotiate : public ErrorInfo<CouldNotNegotiate> {
+public:
+  static char ID;
+
+  CouldNotNegotiate(std::string Signature);
+  std::error_code convertToErrorCode() const override;
+  void log(raw_ostream &OS) const override;
+  const std::string &getSignature() const { return Signature; }
+private:
+  std::string Signature;
+};
+
+template <typename DerivedFunc, typename FnT> class Function;
+
+// RPC Function class.
+// DerivedFunc should be a user defined class with a static 'getName()' method
+// returning a const char* representing the function's name.
+template <typename DerivedFunc, typename RetT, typename... ArgTs>
+class Function<DerivedFunc, RetT(ArgTs...)> {
+public:
+  /// User defined function type.
+  using Type = RetT(ArgTs...);
+
+  /// Return type.
+  using ReturnType = RetT;
+
+  /// Returns the full function prototype as a string.
+  static const char *getPrototype() {
+    static std::string Name = [] {
+      std::string Name;
+      raw_string_ostream(Name)
+          << RPCTypeName<RetT>::getName() << " " << DerivedFunc::getName()
+          << "(" << llvm::orc::rpc::RPCTypeNameSequence<ArgTs...>() << ")";
+      return Name;
+    }();
+    return Name.data();
+  }
+};
+
+/// Allocates RPC function ids during autonegotiation.
+/// Specializations of this class must provide four members:
+///
+/// static T getInvalidId():
+///   Should return a reserved id that will be used to represent missing
+/// functions during autonegotiation.
+///
+/// static T getResponseId():
+///   Should return a reserved id that will be used to send function responses
+/// (return values).
+///
+/// static T getNegotiateId():
+///   Should return a reserved id for the negotiate function, which will be used
+/// to negotiate ids for user defined functions.
+///
+/// template <typename Func> T allocate():
+///   Allocate a unique id for function Func.
+template <typename T, typename = void> class RPCFunctionIdAllocator;
+
+/// This specialization of RPCFunctionIdAllocator provides a default
+/// implementation for integral types.
+template <typename T>
+class RPCFunctionIdAllocator<
+    T, typename std::enable_if<std::is_integral<T>::value>::type> {
+public:
+  static T getInvalidId() { return T(0); }
+  static T getResponseId() { return T(1); }
+  static T getNegotiateId() { return T(2); }
+
+  template <typename Func> T allocate() { return NextId++; }
+
+private:
+  T NextId = 3;
+};
+
+namespace detail {
+
+/// Provides a typedef for a tuple containing the decayed argument types.
+template <typename T> class FunctionArgsTuple;
+
+template <typename RetT, typename... ArgTs>
+class FunctionArgsTuple<RetT(ArgTs...)> {
+public:
+  using Type = std::tuple<typename std::decay<
+      typename std::remove_reference<ArgTs>::type>::type...>;
+};
+
+// ResultTraits provides typedefs and utilities specific to the return type
+// of functions.
+template <typename RetT> class ResultTraits {
+public:
+  // The return type wrapped in llvm::Expected.
+  using ErrorReturnType = Expected<RetT>;
+
+#ifdef _MSC_VER
+  // The ErrorReturnType wrapped in a std::promise.
+  using ReturnPromiseType = std::promise<MSVCPExpected<RetT>>;
+
+  // The ErrorReturnType wrapped in a std::future.
+  using ReturnFutureType = std::future<MSVCPExpected<RetT>>;
+#else
+  // The ErrorReturnType wrapped in a std::promise.
+  using ReturnPromiseType = std::promise<ErrorReturnType>;
+
+  // The ErrorReturnType wrapped in a std::future.
+  using ReturnFutureType = std::future<ErrorReturnType>;
+#endif
+
+  // Create a 'blank' value of the ErrorReturnType, ready and safe to
+  // overwrite.
+  static ErrorReturnType createBlankErrorReturnValue() {
+    return ErrorReturnType(RetT());
+  }
+
+  // Consume an abandoned ErrorReturnType.
+  static void consumeAbandoned(ErrorReturnType RetOrErr) {
+    consumeError(RetOrErr.takeError());
+  }
+};
+
+// ResultTraits specialization for void functions.
+template <> class ResultTraits<void> {
+public:
+  // For void functions, ErrorReturnType is llvm::Error.
+  using ErrorReturnType = Error;
+
+#ifdef _MSC_VER
+  // The ErrorReturnType wrapped in a std::promise.
+  using ReturnPromiseType = std::promise<MSVCPError>;
+
+  // The ErrorReturnType wrapped in a std::future.
+  using ReturnFutureType = std::future<MSVCPError>;
+#else
+  // The ErrorReturnType wrapped in a std::promise.
+  using ReturnPromiseType = std::promise<ErrorReturnType>;
+
+  // The ErrorReturnType wrapped in a std::future.
+  using ReturnFutureType = std::future<ErrorReturnType>;
+#endif
+
+  // Create a 'blank' value of the ErrorReturnType, ready and safe to
+  // overwrite.
+  static ErrorReturnType createBlankErrorReturnValue() {
+    return ErrorReturnType::success();
+  }
+
+  // Consume an abandoned ErrorReturnType.
+  static void consumeAbandoned(ErrorReturnType Err) {
+    consumeError(std::move(Err));
+  }
+};
+
+// ResultTraits<Error> is equivalent to ResultTraits<void>. This allows
+// handlers for void RPC functions to return either void (in which case they
+// implicitly succeed) or Error (in which case their error return is
+// propagated). See usage in HandlerTraits::runHandlerHelper.
+template <> class ResultTraits<Error> : public ResultTraits<void> {};
+
+// ResultTraits<Expected<T>> is equivalent to ResultTraits<T>. This allows
+// handlers for RPC functions returning a T to return either a T (in which
+// case they implicitly succeed) or Expected<T> (in which case their error
+// return is propagated). See usage in HandlerTraits::runHandlerHelper.
+template <typename RetT>
+class ResultTraits<Expected<RetT>> : public ResultTraits<RetT> {};
+
+// Determines whether an RPC function's defined error return type supports
+// error return value.
+template <typename T>
+class SupportsErrorReturn {
+public:
+  static const bool value = false;
+};
+
+template <>
+class SupportsErrorReturn<Error> {
+public:
+  static const bool value = true;
+};
+
+template <typename T>
+class SupportsErrorReturn<Expected<T>> {
+public:
+  static const bool value = true;
+};
+
+// RespondHelper packages return values based on whether or not the declared
+// RPC function return type supports error returns.
+template <bool FuncSupportsErrorReturn>
+class RespondHelper;
+
+// RespondHelper specialization for functions that support error returns.
+template <>
+class RespondHelper<true> {
+public:
+
+  // Send Expected<T>.
+  template <typename WireRetT, typename HandlerRetT, typename ChannelT,
+            typename FunctionIdT, typename SequenceNumberT>
+  static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
+                          SequenceNumberT SeqNo,
+                          Expected<HandlerRetT> ResultOrErr) {
+    if (!ResultOrErr && ResultOrErr.template errorIsA<RPCFatalError>())
+      return ResultOrErr.takeError();
+
+    // Open the response message.
+    if (auto Err = C.startSendMessage(ResponseId, SeqNo))
+      return Err;
+
+    // Serialize the result.
+    if (auto Err =
+        SerializationTraits<ChannelT, WireRetT,
+                            Expected<HandlerRetT>>::serialize(
+                                                     C, std::move(ResultOrErr)))
+      return Err;
+
+    // Close the response message.
+    if (auto Err = C.endSendMessage())
+      return Err;
+    return C.send();
+  }
+
+  template <typename ChannelT, typename FunctionIdT, typename SequenceNumberT>
+  static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
+                          SequenceNumberT SeqNo, Error Err) {
+    if (Err && Err.isA<RPCFatalError>())
+      return Err;
+    if (auto Err2 = C.startSendMessage(ResponseId, SeqNo))
+      return Err2;
+    if (auto Err2 = serializeSeq(C, std::move(Err)))
+      return Err2;
+    if (auto Err2 = C.endSendMessage())
+      return Err2;
+    return C.send();
+  }
+
+};
+
+// RespondHelper specialization for functions that do not support error returns.
+template <>
+class RespondHelper<false> {
+public:
+
+  template <typename WireRetT, typename HandlerRetT, typename ChannelT,
+            typename FunctionIdT, typename SequenceNumberT>
+  static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
+                          SequenceNumberT SeqNo,
+                          Expected<HandlerRetT> ResultOrErr) {
+    if (auto Err = ResultOrErr.takeError())
+      return Err;
+
+    // Open the response message.
+    if (auto Err = C.startSendMessage(ResponseId, SeqNo))
+      return Err;
+
+    // Serialize the result.
+    if (auto Err =
+        SerializationTraits<ChannelT, WireRetT, HandlerRetT>::serialize(
+                                                               C, *ResultOrErr))
+      return Err;
+
+    // End the response message.
+    if (auto Err = C.endSendMessage())
+      return Err;
+
+    return C.send();
+  }
+
+  template <typename ChannelT, typename FunctionIdT, typename SequenceNumberT>
+  static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
+                          SequenceNumberT SeqNo, Error Err) {
+    if (Err)
+      return Err;
+    if (auto Err2 = C.startSendMessage(ResponseId, SeqNo))
+      return Err2;
+    if (auto Err2 = C.endSendMessage())
+      return Err2;
+    return C.send();
+  }
+
+};
+
+
+// Send a response of the given wire return type (WireRetT) over the
+// channel, with the given sequence number.
+template <typename WireRetT, typename HandlerRetT, typename ChannelT,
+          typename FunctionIdT, typename SequenceNumberT>
+Error respond(ChannelT &C, const FunctionIdT &ResponseId,
+              SequenceNumberT SeqNo, Expected<HandlerRetT> ResultOrErr) {
+  return RespondHelper<SupportsErrorReturn<WireRetT>::value>::
+    template sendResult<WireRetT>(C, ResponseId, SeqNo, std::move(ResultOrErr));
+}
+
+// Send an empty response message on the given channel to indicate that
+// the handler ran.
+template <typename WireRetT, typename ChannelT, typename FunctionIdT,
+          typename SequenceNumberT>
+Error respond(ChannelT &C, const FunctionIdT &ResponseId, SequenceNumberT SeqNo,
+              Error Err) {
+  return RespondHelper<SupportsErrorReturn<WireRetT>::value>::
+    sendResult(C, ResponseId, SeqNo, std::move(Err));
+}
+
+// Converts a given type to the equivalent error return type.
+template <typename T> class WrappedHandlerReturn {
+public:
+  using Type = Expected<T>;
+};
+
+template <typename T> class WrappedHandlerReturn<Expected<T>> {
+public:
+  using Type = Expected<T>;
+};
+
+template <> class WrappedHandlerReturn<void> {
+public:
+  using Type = Error;
+};
+
+template <> class WrappedHandlerReturn<Error> {
+public:
+  using Type = Error;
+};
+
+template <> class WrappedHandlerReturn<ErrorSuccess> {
+public:
+  using Type = Error;
+};
+
+// Traits class that strips the response function from the list of handler
+// arguments.
+template <typename FnT> class AsyncHandlerTraits;
+
+template <typename ResultT, typename... ArgTs>
+class AsyncHandlerTraits<Error(std::function<Error(Expected<ResultT>)>, ArgTs...)> {
+public:
+  using Type = Error(ArgTs...);
+  using ResultType = Expected<ResultT>;
+};
+
+template <typename... ArgTs>
+class AsyncHandlerTraits<Error(std::function<Error(Error)>, ArgTs...)> {
+public:
+  using Type = Error(ArgTs...);
+  using ResultType = Error;
+};
+
+template <typename... ArgTs>
+class AsyncHandlerTraits<ErrorSuccess(std::function<Error(Error)>, ArgTs...)> {
+public:
+  using Type = Error(ArgTs...);
+  using ResultType = Error;
+};
+
+template <typename... ArgTs>
+class AsyncHandlerTraits<void(std::function<Error(Error)>, ArgTs...)> {
+public:
+  using Type = Error(ArgTs...);
+  using ResultType = Error;
+};
+
+template <typename ResponseHandlerT, typename... ArgTs>
+class AsyncHandlerTraits<Error(ResponseHandlerT, ArgTs...)> :
+    public AsyncHandlerTraits<Error(typename std::decay<ResponseHandlerT>::type,
+                                    ArgTs...)> {};
+
+// This template class provides utilities related to RPC function handlers.
+// The base case applies to non-function types (the template class is
+// specialized for function types) and inherits from the appropriate
+// speciilization for the given non-function type's call operator.
+template <typename HandlerT>
+class HandlerTraits : public HandlerTraits<decltype(
+                          &std::remove_reference<HandlerT>::type::operator())> {
+};
+
+// Traits for handlers with a given function type.
+template <typename RetT, typename... ArgTs>
+class HandlerTraits<RetT(ArgTs...)> {
+public:
+  // Function type of the handler.
+  using Type = RetT(ArgTs...);
+
+  // Return type of the handler.
+  using ReturnType = RetT;
+
+  // Call the given handler with the given arguments.
+  template <typename HandlerT, typename... TArgTs>
+  static typename WrappedHandlerReturn<RetT>::Type
+  unpackAndRun(HandlerT &Handler, std::tuple<TArgTs...> &Args) {
+    return unpackAndRunHelper(Handler, Args,
+                              std::index_sequence_for<TArgTs...>());
+  }
+
+  // Call the given handler with the given arguments.
+  template <typename HandlerT, typename ResponderT, typename... TArgTs>
+  static Error unpackAndRunAsync(HandlerT &Handler, ResponderT &Responder,
+                                 std::tuple<TArgTs...> &Args) {
+    return unpackAndRunAsyncHelper(Handler, Responder, Args,
+                                   std::index_sequence_for<TArgTs...>());
+  }
+
+  // Call the given handler with the given arguments.
+  template <typename HandlerT>
+  static typename std::enable_if<
+      std::is_void<typename HandlerTraits<HandlerT>::ReturnType>::value,
+      Error>::type
+  run(HandlerT &Handler, ArgTs &&... Args) {
+    Handler(std::move(Args)...);
+    return Error::success();
+  }
+
+  template <typename HandlerT, typename... TArgTs>
+  static typename std::enable_if<
+      !std::is_void<typename HandlerTraits<HandlerT>::ReturnType>::value,
+      typename HandlerTraits<HandlerT>::ReturnType>::type
+  run(HandlerT &Handler, TArgTs... Args) {
+    return Handler(std::move(Args)...);
+  }
+
+  // Serialize arguments to the channel.
+  template <typename ChannelT, typename... CArgTs>
+  static Error serializeArgs(ChannelT &C, const CArgTs... CArgs) {
+    return SequenceSerialization<ChannelT, ArgTs...>::serialize(C, CArgs...);
+  }
+
+  // Deserialize arguments from the channel.
+  template <typename ChannelT, typename... CArgTs>
+  static Error deserializeArgs(ChannelT &C, std::tuple<CArgTs...> &Args) {
+    return deserializeArgsHelper(C, Args, std::index_sequence_for<CArgTs...>());
+  }
+
+private:
+  template <typename ChannelT, typename... CArgTs, size_t... Indexes>
+  static Error deserializeArgsHelper(ChannelT &C, std::tuple<CArgTs...> &Args,
+                                     std::index_sequence<Indexes...> _) {
+    return SequenceSerialization<ChannelT, ArgTs...>::deserialize(
+        C, std::get<Indexes>(Args)...);
+  }
+
+  template <typename HandlerT, typename ArgTuple, size_t... Indexes>
+  static typename WrappedHandlerReturn<
+      typename HandlerTraits<HandlerT>::ReturnType>::Type
+  unpackAndRunHelper(HandlerT &Handler, ArgTuple &Args,
+                     std::index_sequence<Indexes...>) {
+    return run(Handler, std::move(std::get<Indexes>(Args))...);
+  }
+
+  template <typename HandlerT, typename ResponderT, typename ArgTuple,
+            size_t... Indexes>
+  static typename WrappedHandlerReturn<
+      typename HandlerTraits<HandlerT>::ReturnType>::Type
+  unpackAndRunAsyncHelper(HandlerT &Handler, ResponderT &Responder,
+                          ArgTuple &Args, std::index_sequence<Indexes...>) {
+    return run(Handler, Responder, std::move(std::get<Indexes>(Args))...);
+  }
+};
+
+// Handler traits for free functions.
+template <typename RetT, typename... ArgTs>
+class HandlerTraits<RetT(*)(ArgTs...)>
+  : public HandlerTraits<RetT(ArgTs...)> {};
+
+// Handler traits for class methods (especially call operators for lambdas).
+template <typename Class, typename RetT, typename... ArgTs>
+class HandlerTraits<RetT (Class::*)(ArgTs...)>
+    : public HandlerTraits<RetT(ArgTs...)> {};
+
+// Handler traits for const class methods (especially call operators for
+// lambdas).
+template <typename Class, typename RetT, typename... ArgTs>
+class HandlerTraits<RetT (Class::*)(ArgTs...) const>
+    : public HandlerTraits<RetT(ArgTs...)> {};
+
+// Utility to peel the Expected wrapper off a response handler error type.
+template <typename HandlerT> class ResponseHandlerArg;
+
+template <typename ArgT> class ResponseHandlerArg<Error(Expected<ArgT>)> {
+public:
+  using ArgType = Expected<ArgT>;
+  using UnwrappedArgType = ArgT;
+};
+
+template <typename ArgT>
+class ResponseHandlerArg<ErrorSuccess(Expected<ArgT>)> {
+public:
+  using ArgType = Expected<ArgT>;
+  using UnwrappedArgType = ArgT;
+};
+
+template <> class ResponseHandlerArg<Error(Error)> {
+public:
+  using ArgType = Error;
+};
+
+template <> class ResponseHandlerArg<ErrorSuccess(Error)> {
+public:
+  using ArgType = Error;
+};
+
+// ResponseHandler represents a handler for a not-yet-received function call
+// result.
+template <typename ChannelT> class ResponseHandler {
+public:
+  virtual ~ResponseHandler() {}
+
+  // Reads the function result off the wire and acts on it. The meaning of
+  // "act" will depend on how this method is implemented in any given
+  // ResponseHandler subclass but could, for example, mean running a
+  // user-specified handler or setting a promise value.
+  virtual Error handleResponse(ChannelT &C) = 0;
+
+  // Abandons this outstanding result.
+  virtual void abandon() = 0;
+
+  // Create an error instance representing an abandoned response.
+  static Error createAbandonedResponseError() {
+    return make_error<ResponseAbandoned>();
+  }
+};
+
+// ResponseHandler subclass for RPC functions with non-void returns.
+template <typename ChannelT, typename FuncRetT, typename HandlerT>
+class ResponseHandlerImpl : public ResponseHandler<ChannelT> {
+public:
+  ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
+
+  // Handle the result by deserializing it from the channel then passing it
+  // to the user defined handler.
+  Error handleResponse(ChannelT &C) override {
+    using UnwrappedArgType = typename ResponseHandlerArg<
+        typename HandlerTraits<HandlerT>::Type>::UnwrappedArgType;
+    UnwrappedArgType Result;
+    if (auto Err =
+            SerializationTraits<ChannelT, FuncRetT,
+                                UnwrappedArgType>::deserialize(C, Result))
+      return Err;
+    if (auto Err = C.endReceiveMessage())
+      return Err;
+    return Handler(std::move(Result));
+  }
+
+  // Abandon this response by calling the handler with an 'abandoned response'
+  // error.
+  void abandon() override {
+    if (auto Err = Handler(this->createAbandonedResponseError())) {
+      // Handlers should not fail when passed an abandoned response error.
+      report_fatal_error(std::move(Err));
+    }
+  }
+
+private:
+  HandlerT Handler;
+};
+
+// ResponseHandler subclass for RPC functions with void returns.
+template <typename ChannelT, typename HandlerT>
+class ResponseHandlerImpl<ChannelT, void, HandlerT>
+    : public ResponseHandler<ChannelT> {
+public:
+  ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
+
+  // Handle the result (no actual value, just a notification that the function
+  // has completed on the remote end) by calling the user-defined handler with
+  // Error::success().
+  Error handleResponse(ChannelT &C) override {
+    if (auto Err = C.endReceiveMessage())
+      return Err;
+    return Handler(Error::success());
+  }
+
+  // Abandon this response by calling the handler with an 'abandoned response'
+  // error.
+  void abandon() override {
+    if (auto Err = Handler(this->createAbandonedResponseError())) {
+      // Handlers should not fail when passed an abandoned response error.
+      report_fatal_error(std::move(Err));
+    }
+  }
+
+private:
+  HandlerT Handler;
+};
+
+template <typename ChannelT, typename FuncRetT, typename HandlerT>
+class ResponseHandlerImpl<ChannelT, Expected<FuncRetT>, HandlerT>
+    : public ResponseHandler<ChannelT> {
+public:
+  ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
+
+  // Handle the result by deserializing it from the channel then passing it
+  // to the user defined handler.
+  Error handleResponse(ChannelT &C) override {
+    using HandlerArgType = typename ResponseHandlerArg<
+        typename HandlerTraits<HandlerT>::Type>::ArgType;
+    HandlerArgType Result((typename HandlerArgType::value_type()));
+
+    if (auto Err =
+            SerializationTraits<ChannelT, Expected<FuncRetT>,
+                                HandlerArgType>::deserialize(C, Result))
+      return Err;
+    if (auto Err = C.endReceiveMessage())
+      return Err;
+    return Handler(std::move(Result));
+  }
+
+  // Abandon this response by calling the handler with an 'abandoned response'
+  // error.
+  void abandon() override {
+    if (auto Err = Handler(this->createAbandonedResponseError())) {
+      // Handlers should not fail when passed an abandoned response error.
+      report_fatal_error(std::move(Err));
+    }
+  }
+
+private:
+  HandlerT Handler;
+};
+
+template <typename ChannelT, typename HandlerT>
+class ResponseHandlerImpl<ChannelT, Error, HandlerT>
+    : public ResponseHandler<ChannelT> {
+public:
+  ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
+
+  // Handle the result by deserializing it from the channel then passing it
+  // to the user defined handler.
+  Error handleResponse(ChannelT &C) override {
+    Error Result = Error::success();
+    if (auto Err = SerializationTraits<ChannelT, Error, Error>::deserialize(
+            C, Result)) {
+      consumeError(std::move(Result));
+      return Err;
+    }
+    if (auto Err = C.endReceiveMessage()) {
+      consumeError(std::move(Result));
+      return Err;
+    }
+    return Handler(std::move(Result));
+  }
+
+  // Abandon this response by calling the handler with an 'abandoned response'
+  // error.
+  void abandon() override {
+    if (auto Err = Handler(this->createAbandonedResponseError())) {
+      // Handlers should not fail when passed an abandoned response error.
+      report_fatal_error(std::move(Err));
+    }
+  }
+
+private:
+  HandlerT Handler;
+};
+
+// Create a ResponseHandler from a given user handler.
+template <typename ChannelT, typename FuncRetT, typename HandlerT>
+std::unique_ptr<ResponseHandler<ChannelT>> createResponseHandler(HandlerT H) {
+  return std::make_unique<ResponseHandlerImpl<ChannelT, FuncRetT, HandlerT>>(
+      std::move(H));
+}
+
+// Helper for wrapping member functions up as functors. This is useful for
+// installing methods as result handlers.
+template <typename ClassT, typename RetT, typename... ArgTs>
+class MemberFnWrapper {
+public:
+  using MethodT = RetT (ClassT::*)(ArgTs...);
+  MemberFnWrapper(ClassT &Instance, MethodT Method)
+      : Instance(Instance), Method(Method) {}
+  RetT operator()(ArgTs &&... Args) {
+    return (Instance.*Method)(std::move(Args)...);
+  }
+
+private:
+  ClassT &Instance;
+  MethodT Method;
+};
+
+// Helper that provides a Functor for deserializing arguments.
+template <typename... ArgTs> class ReadArgs {
+public:
+  Error operator()() { return Error::success(); }
+};
+
+template <typename ArgT, typename... ArgTs>
+class ReadArgs<ArgT, ArgTs...> : public ReadArgs<ArgTs...> {
+public:
+  ReadArgs(ArgT &Arg, ArgTs &... Args)
+      : ReadArgs<ArgTs...>(Args...), Arg(Arg) {}
+
+  Error operator()(ArgT &ArgVal, ArgTs &... ArgVals) {
+    this->Arg = std::move(ArgVal);
+    return ReadArgs<ArgTs...>::operator()(ArgVals...);
+  }
+
+private:
+  ArgT &Arg;
+};
+
+// Manage sequence numbers.
+template <typename SequenceNumberT> class SequenceNumberManager {
+public:
+  // Reset, making all sequence numbers available.
+  void reset() {
+    std::lock_guard<std::mutex> Lock(SeqNoLock);
+    NextSequenceNumber = 0;
+    FreeSequenceNumbers.clear();
+  }
+
+  // Get the next available sequence number. Will re-use numbers that have
+  // been released.
+  SequenceNumberT getSequenceNumber() {
+    std::lock_guard<std::mutex> Lock(SeqNoLock);
+    if (FreeSequenceNumbers.empty())
+      return NextSequenceNumber++;
+    auto SequenceNumber = FreeSequenceNumbers.back();
+    FreeSequenceNumbers.pop_back();
+    return SequenceNumber;
+  }
+
+  // Release a sequence number, making it available for re-use.
+  void releaseSequenceNumber(SequenceNumberT SequenceNumber) {
+    std::lock_guard<std::mutex> Lock(SeqNoLock);
+    FreeSequenceNumbers.push_back(SequenceNumber);
+  }
+
+private:
+  std::mutex SeqNoLock;
+  SequenceNumberT NextSequenceNumber = 0;
+  std::vector<SequenceNumberT> FreeSequenceNumbers;
+};
+
+// Checks that predicate P holds for each corresponding pair of type arguments
+// from T1 and T2 tuple.
+template <template <class, class> class P, typename T1Tuple, typename T2Tuple>
+class RPCArgTypeCheckHelper;
+
+template <template <class, class> class P>
+class RPCArgTypeCheckHelper<P, std::tuple<>, std::tuple<>> {
+public:
+  static const bool value = true;
+};
+
+template <template <class, class> class P, typename T, typename... Ts,
+          typename U, typename... Us>
+class RPCArgTypeCheckHelper<P, std::tuple<T, Ts...>, std::tuple<U, Us...>> {
+public:
+  static const bool value =
+      P<T, U>::value &&
+      RPCArgTypeCheckHelper<P, std::tuple<Ts...>, std::tuple<Us...>>::value;
+};
+
+template <template <class, class> class P, typename T1Sig, typename T2Sig>
+class RPCArgTypeCheck {
+public:
+  using T1Tuple = typename FunctionArgsTuple<T1Sig>::Type;
+  using T2Tuple = typename FunctionArgsTuple<T2Sig>::Type;
+
+  static_assert(std::tuple_size<T1Tuple>::value >=
+                    std::tuple_size<T2Tuple>::value,
+                "Too many arguments to RPC call");
+  static_assert(std::tuple_size<T1Tuple>::value <=
+                    std::tuple_size<T2Tuple>::value,
+                "Too few arguments to RPC call");
+
+  static const bool value = RPCArgTypeCheckHelper<P, T1Tuple, T2Tuple>::value;
+};
+
+template <typename ChannelT, typename WireT, typename ConcreteT>
+class CanSerialize {
+private:
+  using S = SerializationTraits<ChannelT, WireT, ConcreteT>;
+
+  template <typename T>
+  static std::true_type
+  check(typename std::enable_if<
+        std::is_same<decltype(T::serialize(std::declval<ChannelT &>(),
+                                           std::declval<const ConcreteT &>())),
+                     Error>::value,
+        void *>::type);
+
+  template <typename> static std::false_type check(...);
+
+public:
+  static const bool value = decltype(check<S>(0))::value;
+};
+
+template <typename ChannelT, typename WireT, typename ConcreteT>
+class CanDeserialize {
+private:
+  using S = SerializationTraits<ChannelT, WireT, ConcreteT>;
+
+  template <typename T>
+  static std::true_type
+  check(typename std::enable_if<
+        std::is_same<decltype(T::deserialize(std::declval<ChannelT &>(),
+                                             std::declval<ConcreteT &>())),
+                     Error>::value,
+        void *>::type);
+
+  template <typename> static std::false_type check(...);
+
+public:
+  static const bool value = decltype(check<S>(0))::value;
+};
+
+/// Contains primitive utilities for defining, calling and handling calls to
+/// remote procedures. ChannelT is a bidirectional stream conforming to the
+/// RPCChannel interface (see RPCChannel.h), FunctionIdT is a procedure
+/// identifier type that must be serializable on ChannelT, and SequenceNumberT
+/// is an integral type that will be used to number in-flight function calls.
+///
+/// These utilities support the construction of very primitive RPC utilities.
+/// Their intent is to ensure correct serialization and deserialization of
+/// procedure arguments, and to keep the client and server's view of the API in
+/// sync.
+template <typename ImplT, typename ChannelT, typename FunctionIdT,
+          typename SequenceNumberT>
+class RPCEndpointBase {
+protected:
+  class OrcRPCInvalid : public Function<OrcRPCInvalid, void()> {
+  public:
+    static const char *getName() { return "__orc_rpc$invalid"; }
+  };
+
+  class OrcRPCResponse : public Function<OrcRPCResponse, void()> {
+  public:
+    static const char *getName() { return "__orc_rpc$response"; }
+  };
+
+  class OrcRPCNegotiate
+      : public Function<OrcRPCNegotiate, FunctionIdT(std::string)> {
+  public:
+    static const char *getName() { return "__orc_rpc$negotiate"; }
+  };
+
+  // Helper predicate for testing for the presence of SerializeTraits
+  // serializers.
+  template <typename WireT, typename ConcreteT>
+  class CanSerializeCheck : detail::CanSerialize<ChannelT, WireT, ConcreteT> {
+  public:
+    using detail::CanSerialize<ChannelT, WireT, ConcreteT>::value;
+
+    static_assert(value, "Missing serializer for argument (Can't serialize the "
+                         "first template type argument of CanSerializeCheck "
+                         "from the second)");
+  };
+
+  // Helper predicate for testing for the presence of SerializeTraits
+  // deserializers.
+  template <typename WireT, typename ConcreteT>
+  class CanDeserializeCheck
+      : detail::CanDeserialize<ChannelT, WireT, ConcreteT> {
+  public:
+    using detail::CanDeserialize<ChannelT, WireT, ConcreteT>::value;
+
+    static_assert(value, "Missing deserializer for argument (Can't deserialize "
+                         "the second template type argument of "
+                         "CanDeserializeCheck from the first)");
+  };
+
+public:
+  /// Construct an RPC instance on a channel.
+  RPCEndpointBase(ChannelT &C, bool LazyAutoNegotiation)
+      : C(C), LazyAutoNegotiation(LazyAutoNegotiation) {
+    // Hold ResponseId in a special variable, since we expect Response to be
+    // called relatively frequently, and want to avoid the map lookup.
+    ResponseId = FnIdAllocator.getResponseId();
+    RemoteFunctionIds[OrcRPCResponse::getPrototype()] = ResponseId;
+
+    // Register the negotiate function id and handler.
+    auto NegotiateId = FnIdAllocator.getNegotiateId();
+    RemoteFunctionIds[OrcRPCNegotiate::getPrototype()] = NegotiateId;
+    Handlers[NegotiateId] = wrapHandler<OrcRPCNegotiate>(
+        [this](const std::string &Name) { return handleNegotiate(Name); });
+  }
+
+
+  /// Negotiate a function id for Func with the other end of the channel.
+  template <typename Func> Error negotiateFunction(bool Retry = false) {
+    return getRemoteFunctionId<Func>(true, Retry).takeError();
+  }
+
+  /// Append a call Func, does not call send on the channel.
+  /// The first argument specifies a user-defined handler to be run when the
+  /// function returns. The handler should take an Expected<Func::ReturnType>,
+  /// or an Error (if Func::ReturnType is void). The handler will be called
+  /// with an error if the return value is abandoned due to a channel error.
+  template <typename Func, typename HandlerT, typename... ArgTs>
+  Error appendCallAsync(HandlerT Handler, const ArgTs &... Args) {
+
+    static_assert(
+        detail::RPCArgTypeCheck<CanSerializeCheck, typename Func::Type,
+                                void(ArgTs...)>::value,
+        "");
+
+    // Look up the function ID.
+    FunctionIdT FnId;
+    if (auto FnIdOrErr = getRemoteFunctionId<Func>(LazyAutoNegotiation, false))
+      FnId = *FnIdOrErr;
+    else {
+      // Negotiation failed. Notify the handler then return the negotiate-failed
+      // error.
+      cantFail(Handler(make_error<ResponseAbandoned>()));
+      return FnIdOrErr.takeError();
+    }
+
+    SequenceNumberT SeqNo; // initialized in locked scope below.
+    {
+      // Lock the pending responses map and sequence number manager.
+      std::lock_guard<std::mutex> Lock(ResponsesMutex);
+
+      // Allocate a sequence number.
+      SeqNo = SequenceNumberMgr.getSequenceNumber();
+      assert(!PendingResponses.count(SeqNo) &&
+             "Sequence number already allocated");
+
+      // Install the user handler.
+      PendingResponses[SeqNo] =
+        detail::createResponseHandler<ChannelT, typename Func::ReturnType>(
+            std::move(Handler));
+    }
+
+    // Open the function call message.
+    if (auto Err = C.startSendMessage(FnId, SeqNo)) {
+      abandonPendingResponses();
+      return Err;
+    }
+
+    // Serialize the call arguments.
+    if (auto Err = detail::HandlerTraits<typename Func::Type>::serializeArgs(
+            C, Args...)) {
+      abandonPendingResponses();
+      return Err;
+    }
+
+    // Close the function call messagee.
+    if (auto Err = C.endSendMessage()) {
+      abandonPendingResponses();
+      return Err;
+    }
+
+    return Error::success();
+  }
+
+  Error sendAppendedCalls() { return C.send(); };
+
+  template <typename Func, typename HandlerT, typename... ArgTs>
+  Error callAsync(HandlerT Handler, const ArgTs &... Args) {
+    if (auto Err = appendCallAsync<Func>(std::move(Handler), Args...))
+      return Err;
+    return C.send();
+  }
+
+  /// Handle one incoming call.
+  Error handleOne() {
+    FunctionIdT FnId;
+    SequenceNumberT SeqNo;
+    if (auto Err = C.startReceiveMessage(FnId, SeqNo)) {
+      abandonPendingResponses();
+      return Err;
+    }
+    if (FnId == ResponseId)
+      return handleResponse(SeqNo);
+    auto I = Handlers.find(FnId);
+    if (I != Handlers.end())
+      return I->second(C, SeqNo);
+
+    // else: No handler found. Report error to client?
+    return make_error<BadFunctionCall<FunctionIdT, SequenceNumberT>>(FnId,
+                                                                     SeqNo);
+  }
+
+  /// Helper for handling setter procedures - this method returns a functor that
+  /// sets the variables referred to by Args... to values deserialized from the
+  /// channel.
+  /// E.g.
+  ///
+  ///   typedef Function<0, bool, int> Func1;
+  ///
+  ///   ...
+  ///   bool B;
+  ///   int I;
+  ///   if (auto Err = expect<Func1>(Channel, readArgs(B, I)))
+  ///     /* Handle Args */ ;
+  ///
+  template <typename... ArgTs>
+  static detail::ReadArgs<ArgTs...> readArgs(ArgTs &... Args) {
+    return detail::ReadArgs<ArgTs...>(Args...);
+  }
+
+  /// Abandon all outstanding result handlers.
+  ///
+  /// This will call all currently registered result handlers to receive an
+  /// "abandoned" error as their argument. This is used internally by the RPC
+  /// in error situations, but can also be called directly by clients who are
+  /// disconnecting from the remote and don't or can't expect responses to their
+  /// outstanding calls. (Especially for outstanding blocking calls, calling
+  /// this function may be necessary to avoid dead threads).
+  void abandonPendingResponses() {
+    // Lock the pending responses map and sequence number manager.
+    std::lock_guard<std::mutex> Lock(ResponsesMutex);
+
+    for (auto &KV : PendingResponses)
+      KV.second->abandon();
+    PendingResponses.clear();
+    SequenceNumberMgr.reset();
+  }
+
+  /// Remove the handler for the given function.
+  /// A handler must currently be registered for this function.
+  template <typename Func>
+  void removeHandler() {
+    auto IdItr = LocalFunctionIds.find(Func::getPrototype());
+    assert(IdItr != LocalFunctionIds.end() &&
+           "Function does not have a registered handler");
+    auto HandlerItr = Handlers.find(IdItr->second);
+    assert(HandlerItr != Handlers.end() &&
+           "Function does not have a registered handler");
+    Handlers.erase(HandlerItr);
+  }
+
+  /// Clear all handlers.
+  void clearHandlers() {
+    Handlers.clear();
+  }
+
+protected:
+
+  FunctionIdT getInvalidFunctionId() const {
+    return FnIdAllocator.getInvalidId();
+  }
+
+  /// Add the given handler to the handler map and make it available for
+  /// autonegotiation and execution.
+  template <typename Func, typename HandlerT>
+  void addHandlerImpl(HandlerT Handler) {
+
+    static_assert(detail::RPCArgTypeCheck<
+                      CanDeserializeCheck, typename Func::Type,
+                      typename detail::HandlerTraits<HandlerT>::Type>::value,
+                  "");
+
+    FunctionIdT NewFnId = FnIdAllocator.template allocate<Func>();
+    LocalFunctionIds[Func::getPrototype()] = NewFnId;
+    Handlers[NewFnId] = wrapHandler<Func>(std::move(Handler));
+  }
+
+  template <typename Func, typename HandlerT>
+  void addAsyncHandlerImpl(HandlerT Handler) {
+
+    static_assert(detail::RPCArgTypeCheck<
+                      CanDeserializeCheck, typename Func::Type,
+                      typename detail::AsyncHandlerTraits<
+                        typename detail::HandlerTraits<HandlerT>::Type
+                      >::Type>::value,
+                  "");
+
+    FunctionIdT NewFnId = FnIdAllocator.template allocate<Func>();
+    LocalFunctionIds[Func::getPrototype()] = NewFnId;
+    Handlers[NewFnId] = wrapAsyncHandler<Func>(std::move(Handler));
+  }
+
+  Error handleResponse(SequenceNumberT SeqNo) {
+    using Handler = typename decltype(PendingResponses)::mapped_type;
+    Handler PRHandler;
+
+    {
+      // Lock the pending responses map and sequence number manager.
+      std::unique_lock<std::mutex> Lock(ResponsesMutex);
+      auto I = PendingResponses.find(SeqNo);
+
+      if (I != PendingResponses.end()) {
+        PRHandler = std::move(I->second);
+        PendingResponses.erase(I);
+        SequenceNumberMgr.releaseSequenceNumber(SeqNo);
+      } else {
+        // Unlock the pending results map to prevent recursive lock.
+        Lock.unlock();
+        abandonPendingResponses();
+        return make_error<
+                 InvalidSequenceNumberForResponse<SequenceNumberT>>(SeqNo);
+      }
+    }
+
+    assert(PRHandler &&
+           "If we didn't find a response handler we should have bailed out");
+
+    if (auto Err = PRHandler->handleResponse(C)) {
+      abandonPendingResponses();
+      return Err;
+    }
+
+    return Error::success();
+  }
+
+  FunctionIdT handleNegotiate(const std::string &Name) {
+    auto I = LocalFunctionIds.find(Name);
+    if (I == LocalFunctionIds.end())
+      return getInvalidFunctionId();
+    return I->second;
+  }
+
+  // Find the remote FunctionId for the given function.
+  template <typename Func>
+  Expected<FunctionIdT> getRemoteFunctionId(bool NegotiateIfNotInMap,
+                                            bool NegotiateIfInvalid) {
+    bool DoNegotiate;
+
+    // Check if we already have a function id...
+    auto I = RemoteFunctionIds.find(Func::getPrototype());
+    if (I != RemoteFunctionIds.end()) {
+      // If it's valid there's nothing left to do.
+      if (I->second != getInvalidFunctionId())
+        return I->second;
+      DoNegotiate = NegotiateIfInvalid;
+    } else
+      DoNegotiate = NegotiateIfNotInMap;
+
+    // We don't have a function id for Func yet, but we're allowed to try to
+    // negotiate one.
+    if (DoNegotiate) {
+      auto &Impl = static_cast<ImplT &>(*this);
+      if (auto RemoteIdOrErr =
+          Impl.template callB<OrcRPCNegotiate>(Func::getPrototype())) {
+        RemoteFunctionIds[Func::getPrototype()] = *RemoteIdOrErr;
+        if (*RemoteIdOrErr == getInvalidFunctionId())
+          return make_error<CouldNotNegotiate>(Func::getPrototype());
+        return *RemoteIdOrErr;
+      } else
+        return RemoteIdOrErr.takeError();
+    }
+
+    // No key was available in the map and we weren't allowed to try to
+    // negotiate one, so return an unknown function error.
+    return make_error<CouldNotNegotiate>(Func::getPrototype());
+  }
+
+  using WrappedHandlerFn = std::function<Error(ChannelT &, SequenceNumberT)>;
+
+  // Wrap the given user handler in the necessary argument-deserialization code,
+  // result-serialization code, and call to the launch policy (if present).
+  template <typename Func, typename HandlerT>
+  WrappedHandlerFn wrapHandler(HandlerT Handler) {
+    return [this, Handler](ChannelT &Channel,
+                           SequenceNumberT SeqNo) mutable -> Error {
+      // Start by deserializing the arguments.
+      using ArgsTuple =
+          typename detail::FunctionArgsTuple<
+            typename detail::HandlerTraits<HandlerT>::Type>::Type;
+      auto Args = std::make_shared<ArgsTuple>();
+
+      if (auto Err =
+              detail::HandlerTraits<typename Func::Type>::deserializeArgs(
+                  Channel, *Args))
+        return Err;
+
+      // GCC 4.7 and 4.8 incorrectly issue a -Wunused-but-set-variable warning
+      // for RPCArgs. Void cast RPCArgs to work around this for now.
+      // FIXME: Remove this workaround once we can assume a working GCC version.
+      (void)Args;
+
+      // End receieve message, unlocking the channel for reading.
+      if (auto Err = Channel.endReceiveMessage())
+        return Err;
+
+      using HTraits = detail::HandlerTraits<HandlerT>;
+      using FuncReturn = typename Func::ReturnType;
+      return detail::respond<FuncReturn>(Channel, ResponseId, SeqNo,
+                                         HTraits::unpackAndRun(Handler, *Args));
+    };
+  }
+
+  // Wrap the given user handler in the necessary argument-deserialization code,
+  // result-serialization code, and call to the launch policy (if present).
+  template <typename Func, typename HandlerT>
+  WrappedHandlerFn wrapAsyncHandler(HandlerT Handler) {
+    return [this, Handler](ChannelT &Channel,
+                           SequenceNumberT SeqNo) mutable -> Error {
+      // Start by deserializing the arguments.
+      using AHTraits = detail::AsyncHandlerTraits<
+                         typename detail::HandlerTraits<HandlerT>::Type>;
+      using ArgsTuple =
+          typename detail::FunctionArgsTuple<typename AHTraits::Type>::Type;
+      auto Args = std::make_shared<ArgsTuple>();
+
+      if (auto Err =
+              detail::HandlerTraits<typename Func::Type>::deserializeArgs(
+                  Channel, *Args))
+        return Err;
+
+      // GCC 4.7 and 4.8 incorrectly issue a -Wunused-but-set-variable warning
+      // for RPCArgs. Void cast RPCArgs to work around this for now.
+      // FIXME: Remove this workaround once we can assume a working GCC version.
+      (void)Args;
+
+      // End receieve message, unlocking the channel for reading.
+      if (auto Err = Channel.endReceiveMessage())
+        return Err;
+
+      using HTraits = detail::HandlerTraits<HandlerT>;
+      using FuncReturn = typename Func::ReturnType;
+      auto Responder =
+        [this, SeqNo](typename AHTraits::ResultType RetVal) -> Error {
+          return detail::respond<FuncReturn>(C, ResponseId, SeqNo,
+                                             std::move(RetVal));
+        };
+
+      return HTraits::unpackAndRunAsync(Handler, Responder, *Args);
+    };
+  }
+
+  ChannelT &C;
+
+  bool LazyAutoNegotiation;
+
+  RPCFunctionIdAllocator<FunctionIdT> FnIdAllocator;
+
+  FunctionIdT ResponseId;
+  std::map<std::string, FunctionIdT> LocalFunctionIds;
+  std::map<const char *, FunctionIdT> RemoteFunctionIds;
+
+  std::map<FunctionIdT, WrappedHandlerFn> Handlers;
+
+  std::mutex ResponsesMutex;
+  detail::SequenceNumberManager<SequenceNumberT> SequenceNumberMgr;
+  std::map<SequenceNumberT, std::unique_ptr<detail::ResponseHandler<ChannelT>>>
+      PendingResponses;
+};
+
+} // end namespace detail
+
+template <typename ChannelT, typename FunctionIdT = uint32_t,
+          typename SequenceNumberT = uint32_t>
+class MultiThreadedRPCEndpoint
+    : public detail::RPCEndpointBase<
+          MultiThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
+          ChannelT, FunctionIdT, SequenceNumberT> {
+private:
+  using BaseClass =
+      detail::RPCEndpointBase<
+        MultiThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
+        ChannelT, FunctionIdT, SequenceNumberT>;
+
+public:
+  MultiThreadedRPCEndpoint(ChannelT &C, bool LazyAutoNegotiation)
+      : BaseClass(C, LazyAutoNegotiation) {}
+
+  /// Add a handler for the given RPC function.
+  /// This installs the given handler functor for the given RPC Function, and
+  /// makes the RPC function available for negotiation/calling from the remote.
+  template <typename Func, typename HandlerT>
+  void addHandler(HandlerT Handler) {
+    return this->template addHandlerImpl<Func>(std::move(Handler));
+  }
+
+  /// Add a class-method as a handler.
+  template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
+  void addHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
+    addHandler<Func>(
+      detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
+  }
+
+  template <typename Func, typename HandlerT>
+  void addAsyncHandler(HandlerT Handler) {
+    return this->template addAsyncHandlerImpl<Func>(std::move(Handler));
+  }
+
+  /// Add a class-method as a handler.
+  template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
+  void addAsyncHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
+    addAsyncHandler<Func>(
+      detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
+  }
+
+  /// Return type for non-blocking call primitives.
+  template <typename Func>
+  using NonBlockingCallResult = typename detail::ResultTraits<
+      typename Func::ReturnType>::ReturnFutureType;
+
+  /// Call Func on Channel C. Does not block, does not call send. Returns a pair
+  /// of a future result and the sequence number assigned to the result.
+  ///
+  /// This utility function is primarily used for single-threaded mode support,
+  /// where the sequence number can be used to wait for the corresponding
+  /// result. In multi-threaded mode the appendCallNB method, which does not
+  /// return the sequence numeber, should be preferred.
+  template <typename Func, typename... ArgTs>
+  Expected<NonBlockingCallResult<Func>> appendCallNB(const ArgTs &... Args) {
+    using RTraits = detail::ResultTraits<typename Func::ReturnType>;
+    using ErrorReturn = typename RTraits::ErrorReturnType;
+    using ErrorReturnPromise = typename RTraits::ReturnPromiseType;
+
+    ErrorReturnPromise Promise;
+    auto FutureResult = Promise.get_future();
+
+    if (auto Err = this->template appendCallAsync<Func>(
+            [Promise = std::move(Promise)](ErrorReturn RetOrErr) mutable {
+              Promise.set_value(std::move(RetOrErr));
+              return Error::success();
+            },
+            Args...)) {
+      RTraits::consumeAbandoned(FutureResult.get());
+      return std::move(Err);
+    }
+    return std::move(FutureResult);
+  }
+
+  /// The same as appendCallNBWithSeq, except that it calls C.send() to
+  /// flush the channel after serializing the call.
+  template <typename Func, typename... ArgTs>
+  Expected<NonBlockingCallResult<Func>> callNB(const ArgTs &... Args) {
+    auto Result = appendCallNB<Func>(Args...);
+    if (!Result)
+      return Result;
+    if (auto Err = this->C.send()) {
+      this->abandonPendingResponses();
+      detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
+          std::move(Result->get()));
+      return std::move(Err);
+    }
+    return Result;
+  }
+
+  /// Call Func on Channel C. Blocks waiting for a result. Returns an Error
+  /// for void functions or an Expected<T> for functions returning a T.
+  ///
+  /// This function is for use in threaded code where another thread is
+  /// handling responses and incoming calls.
+  template <typename Func, typename... ArgTs,
+            typename AltRetT = typename Func::ReturnType>
+  typename detail::ResultTraits<AltRetT>::ErrorReturnType
+  callB(const ArgTs &... Args) {
+    if (auto FutureResOrErr = callNB<Func>(Args...))
+      return FutureResOrErr->get();
+    else
+      return FutureResOrErr.takeError();
+  }
+
+  /// Handle incoming RPC calls.
+  Error handlerLoop() {
+    while (true)
+      if (auto Err = this->handleOne())
+        return Err;
+    return Error::success();
+  }
+};
+
+template <typename ChannelT, typename FunctionIdT = uint32_t,
+          typename SequenceNumberT = uint32_t>
+class SingleThreadedRPCEndpoint
+    : public detail::RPCEndpointBase<
+          SingleThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
+          ChannelT, FunctionIdT, SequenceNumberT> {
+private:
+  using BaseClass =
+      detail::RPCEndpointBase<
+        SingleThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
+        ChannelT, FunctionIdT, SequenceNumberT>;
+
+public:
+  SingleThreadedRPCEndpoint(ChannelT &C, bool LazyAutoNegotiation)
+      : BaseClass(C, LazyAutoNegotiation) {}
+
+  template <typename Func, typename HandlerT>
+  void addHandler(HandlerT Handler) {
+    return this->template addHandlerImpl<Func>(std::move(Handler));
+  }
+
+  template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
+  void addHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
+    addHandler<Func>(
+        detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
+  }
+
+  template <typename Func, typename HandlerT>
+  void addAsyncHandler(HandlerT Handler) {
+    return this->template addAsyncHandlerImpl<Func>(std::move(Handler));
+  }
+
+  /// Add a class-method as a handler.
+  template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
+  void addAsyncHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
+    addAsyncHandler<Func>(
+      detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
+  }
+
+  template <typename Func, typename... ArgTs,
+            typename AltRetT = typename Func::ReturnType>
+  typename detail::ResultTraits<AltRetT>::ErrorReturnType
+  callB(const ArgTs &... Args) {
+    bool ReceivedResponse = false;
+    using ResultType = typename detail::ResultTraits<AltRetT>::ErrorReturnType;
+    auto Result = detail::ResultTraits<AltRetT>::createBlankErrorReturnValue();
+
+    // We have to 'Check' result (which we know is in a success state at this
+    // point) so that it can be overwritten in the async handler.
+    (void)!!Result;
+
+    if (auto Err = this->template appendCallAsync<Func>(
+            [&](ResultType R) {
+              Result = std::move(R);
+              ReceivedResponse = true;
+              return Error::success();
+            },
+            Args...)) {
+      detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
+          std::move(Result));
+      return std::move(Err);
+    }
+
+    if (auto Err = this->C.send()) {
+      detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
+          std::move(Result));
+      return std::move(Err);
+    }
+
+    while (!ReceivedResponse) {
+      if (auto Err = this->handleOne()) {
+        detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
+            std::move(Result));
+        return std::move(Err);
+      }
+    }
+
+    return Result;
+  }
+};
+
+/// Asynchronous dispatch for a function on an RPC endpoint.
+template <typename RPCClass, typename Func>
+class RPCAsyncDispatch {
+public:
+  RPCAsyncDispatch(RPCClass &Endpoint) : Endpoint(Endpoint) {}
+
+  template <typename HandlerT, typename... ArgTs>
+  Error operator()(HandlerT Handler, const ArgTs &... Args) const {
+    return Endpoint.template appendCallAsync<Func>(std::move(Handler), Args...);
+  }
+
+private:
+  RPCClass &Endpoint;
+};
+
+/// Construct an asynchronous dispatcher from an RPC endpoint and a Func.
+template <typename Func, typename RPCEndpointT>
+RPCAsyncDispatch<RPCEndpointT, Func> rpcAsyncDispatch(RPCEndpointT &Endpoint) {
+  return RPCAsyncDispatch<RPCEndpointT, Func>(Endpoint);
+}
+
+/// Allows a set of asynchrounous calls to be dispatched, and then
+///        waited on as a group.
+class ParallelCallGroup {
+public:
+
+  ParallelCallGroup() = default;
+  ParallelCallGroup(const ParallelCallGroup &) = delete;
+  ParallelCallGroup &operator=(const ParallelCallGroup &) = delete;
+
+  /// Make as asynchronous call.
+  template <typename AsyncDispatcher, typename HandlerT, typename... ArgTs>
+  Error call(const AsyncDispatcher &AsyncDispatch, HandlerT Handler,
+             const ArgTs &... Args) {
+    // Increment the count of outstanding calls. This has to happen before
+    // we invoke the call, as the handler may (depending on scheduling)
+    // be run immediately on another thread, and we don't want the decrement
+    // in the wrapped handler below to run before the increment.
+    {
+      std::unique_lock<std::mutex> Lock(M);
+      ++NumOutstandingCalls;
+    }
+
+    // Wrap the user handler in a lambda that will decrement the
+    // outstanding calls count, then poke the condition variable.
+    using ArgType = typename detail::ResponseHandlerArg<
+        typename detail::HandlerTraits<HandlerT>::Type>::ArgType;
+    auto WrappedHandler = [this, Handler = std::move(Handler)](ArgType Arg) {
+      auto Err = Handler(std::move(Arg));
+      std::unique_lock<std::mutex> Lock(M);
+      --NumOutstandingCalls;
+      CV.notify_all();
+      return Err;
+    };
+
+    return AsyncDispatch(std::move(WrappedHandler), Args...);
+  }
+
+  /// Blocks until all calls have been completed and their return value
+  ///        handlers run.
+  void wait() {
+    std::unique_lock<std::mutex> Lock(M);
+    while (NumOutstandingCalls > 0)
+      CV.wait(Lock);
+  }
+
+private:
+  std::mutex M;
+  std::condition_variable CV;
+  uint32_t NumOutstandingCalls = 0;
+};
+
+/// Convenience class for grouping RPC Functions into APIs that can be
+///        negotiated as a block.
+///
+template <typename... Funcs>
+class APICalls {
+public:
+
+  /// Test whether this API contains Function F.
+  template <typename F>
+  class Contains {
+  public:
+    static const bool value = false;
+  };
+
+  /// Negotiate all functions in this API.
+  template <typename RPCEndpoint>
+  static Error negotiate(RPCEndpoint &R) {
+    return Error::success();
+  }
+};
+
+template <typename Func, typename... Funcs>
+class APICalls<Func, Funcs...> {
+public:
+
+  template <typename F>
+  class Contains {
+  public:
+    static const bool value = std::is_same<F, Func>::value |
+                              APICalls<Funcs...>::template Contains<F>::value;
+  };
+
+  template <typename RPCEndpoint>
+  static Error negotiate(RPCEndpoint &R) {
+    if (auto Err = R.template negotiateFunction<Func>())
+      return Err;
+    return APICalls<Funcs...>::negotiate(R);
+  }
+
+};
+
+template <typename... InnerFuncs, typename... Funcs>
+class APICalls<APICalls<InnerFuncs...>, Funcs...> {
+public:
+
+  template <typename F>
+  class Contains {
+  public:
+    static const bool value =
+      APICalls<InnerFuncs...>::template Contains<F>::value |
+      APICalls<Funcs...>::template Contains<F>::value;
+  };
+
+  template <typename RPCEndpoint>
+  static Error negotiate(RPCEndpoint &R) {
+    if (auto Err = APICalls<InnerFuncs...>::negotiate(R))
+      return Err;
+    return APICalls<Funcs...>::negotiate(R);
+  }
+
+};
+
+} // end namespace rpc
+} // end namespace orc
+} // end namespace llvm
+
+#endif
diff --git a/llvm/include/llvm/ExecutionEngine/Orc/RPC/RawByteChannel.h b/llvm/include/llvm/ExecutionEngine/Orc/RPC/RawByteChannel.h
new file mode 100644
index 00000000000..50e26f8449d
--- /dev/null
+++ b/llvm/include/llvm/ExecutionEngine/Orc/RPC/RawByteChannel.h
@@ -0,0 +1,184 @@
+//===- llvm/ExecutionEngine/Orc/RPC/RawByteChannel.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 LLVM_EXECUTIONENGINE_ORC_RAWBYTECHANNEL_H
+#define LLVM_EXECUTIONENGINE_ORC_RAWBYTECHANNEL_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ExecutionEngine/Orc/RPC/RPCSerialization.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/Error.h"
+#include <cstdint>
+#include <mutex>
+#include <string>
+#include <type_traits>
+
+namespace llvm {
+namespace orc {
+namespace rpc {
+
+/// Interface for byte-streams to be used with RPC.
+class RawByteChannel {
+public:
+  virtual ~RawByteChannel() = default;
+
+  /// Read Size bytes from the stream into *Dst.
+  virtual Error readBytes(char *Dst, unsigned Size) = 0;
+
+  /// Read size bytes from *Src and append them to the stream.
+  virtual Error appendBytes(const char *Src, unsigned Size) = 0;
+
+  /// Flush the stream if possible.
+  virtual Error send() = 0;
+
+  /// Notify the channel that we're starting a message send.
+  /// Locks the channel for writing.
+  template <typename FunctionIdT, typename SequenceIdT>
+  Error startSendMessage(const FunctionIdT &FnId, const SequenceIdT &SeqNo) {
+    writeLock.lock();
+    if (auto Err = serializeSeq(*this, FnId, SeqNo)) {
+      writeLock.unlock();
+      return Err;
+    }
+    return Error::success();
+  }
+
+  /// Notify the channel that we're ending a message send.
+  /// Unlocks the channel for writing.
+  Error endSendMessage() {
+    writeLock.unlock();
+    return Error::success();
+  }
+
+  /// Notify the channel that we're starting a message receive.
+  /// Locks the channel for reading.
+  template <typename FunctionIdT, typename SequenceNumberT>
+  Error startReceiveMessage(FunctionIdT &FnId, SequenceNumberT &SeqNo) {
+    readLock.lock();
+    if (auto Err = deserializeSeq(*this, FnId, SeqNo)) {
+      readLock.unlock();
+      return Err;
+    }
+    return Error::success();
+  }
+
+  /// Notify the channel that we're ending a message receive.
+  /// Unlocks the channel for reading.
+  Error endReceiveMessage() {
+    readLock.unlock();
+    return Error::success();
+  }
+
+  /// Get the lock for stream reading.
+  std::mutex &getReadLock() { return readLock; }
+
+  /// Get the lock for stream writing.
+  std::mutex &getWriteLock() { return writeLock; }
+
+private:
+  std::mutex readLock, writeLock;
+};
+
+template <typename ChannelT, typename T>
+class SerializationTraits<
+    ChannelT, T, T,
+    typename std::enable_if<
+        std::is_base_of<RawByteChannel, ChannelT>::value &&
+        (std::is_same<T, uint8_t>::value || std::is_same<T, int8_t>::value ||
+         std::is_same<T, uint16_t>::value || std::is_same<T, int16_t>::value ||
+         std::is_same<T, uint32_t>::value || std::is_same<T, int32_t>::value ||
+         std::is_same<T, uint64_t>::value || std::is_same<T, int64_t>::value ||
+         std::is_same<T, char>::value)>::type> {
+public:
+  static Error serialize(ChannelT &C, T V) {
+    support::endian::byte_swap<T, support::big>(V);
+    return C.appendBytes(reinterpret_cast<const char *>(&V), sizeof(T));
+  };
+
+  static Error deserialize(ChannelT &C, T &V) {
+    if (auto Err = C.readBytes(reinterpret_cast<char *>(&V), sizeof(T)))
+      return Err;
+    support::endian::byte_swap<T, support::big>(V);
+    return Error::success();
+  };
+};
+
+template <typename ChannelT>
+class SerializationTraits<ChannelT, bool, bool,
+                          typename std::enable_if<std::is_base_of<
+                              RawByteChannel, ChannelT>::value>::type> {
+public:
+  static Error serialize(ChannelT &C, bool V) {
+    uint8_t Tmp = V ? 1 : 0;
+    if (auto Err =
+          C.appendBytes(reinterpret_cast<const char *>(&Tmp), 1))
+      return Err;
+    return Error::success();
+  }
+
+  static Error deserialize(ChannelT &C, bool &V) {
+    uint8_t Tmp = 0;
+    if (auto Err = C.readBytes(reinterpret_cast<char *>(&Tmp), 1))
+      return Err;
+    V = Tmp != 0;
+    return Error::success();
+  }
+};
+
+template <typename ChannelT>
+class SerializationTraits<ChannelT, std::string, StringRef,
+                          typename std::enable_if<std::is_base_of<
+                              RawByteChannel, ChannelT>::value>::type> {
+public:
+  /// RPC channel serialization for std::strings.
+  static Error serialize(RawByteChannel &C, StringRef S) {
+    if (auto Err = serializeSeq(C, static_cast<uint64_t>(S.size())))
+      return Err;
+    return C.appendBytes((const char *)S.data(), S.size());
+  }
+};
+
+template <typename ChannelT, typename T>
+class SerializationTraits<ChannelT, std::string, T,
+                          typename std::enable_if<
+                            std::is_base_of<RawByteChannel, ChannelT>::value &&
+                            (std::is_same<T, const char*>::value ||
+                             std::is_same<T, char*>::value)>::type> {
+public:
+  static Error serialize(RawByteChannel &C, const char *S) {
+    return SerializationTraits<ChannelT, std::string, StringRef>::serialize(C,
+                                                                            S);
+  }
+};
+
+template <typename ChannelT>
+class SerializationTraits<ChannelT, std::string, std::string,
+                          typename std::enable_if<std::is_base_of<
+                              RawByteChannel, ChannelT>::value>::type> {
+public:
+  /// RPC channel serialization for std::strings.
+  static Error serialize(RawByteChannel &C, const std::string &S) {
+    return SerializationTraits<ChannelT, std::string, StringRef>::serialize(C,
+                                                                            S);
+  }
+
+  /// RPC channel deserialization for std::strings.
+  static Error deserialize(RawByteChannel &C, std::string &S) {
+    uint64_t Count = 0;
+    if (auto Err = deserializeSeq(C, Count))
+      return Err;
+    S.resize(Count);
+    return C.readBytes(&S[0], Count);
+  }
+};
+
+} // end namespace rpc
+} // end namespace orc
+} // end namespace llvm
+
+#endif // LLVM_EXECUTIONENGINE_ORC_RAWBYTECHANNEL_H
diff --git a/llvm/include/llvm/ExecutionEngine/Orc/RPCSerialization.h b/llvm/include/llvm/ExecutionEngine/Orc/RPCSerialization.h
deleted file mode 100644
index 752a0a34e0a..00000000000
--- a/llvm/include/llvm/ExecutionEngine/Orc/RPCSerialization.h
+++ /dev/null
@@ -1,703 +0,0 @@
-//===- llvm/ExecutionEngine/Orc/RPCSerialization.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 LLVM_EXECUTIONENGINE_ORC_RPCSERIALIZATION_H
-#define LLVM_EXECUTIONENGINE_ORC_RPCSERIALIZATION_H
-
-#include "OrcError.h"
-#include "llvm/Support/thread.h"
-#include <map>
-#include <mutex>
-#include <set>
-#include <sstream>
-#include <string>
-#include <vector>
-
-namespace llvm {
-namespace orc {
-namespace rpc {
-
-template <typename T>
-class RPCTypeName;
-
-/// TypeNameSequence is a utility for rendering sequences of types to a string
-/// by rendering each type, separated by ", ".
-template <typename... ArgTs> class RPCTypeNameSequence {};
-
-/// Render an empty TypeNameSequence to an ostream.
-template <typename OStream>
-OStream &operator<<(OStream &OS, const RPCTypeNameSequence<> &V) {
-  return OS;
-}
-
-/// Render a TypeNameSequence of a single type to an ostream.
-template <typename OStream, typename ArgT>
-OStream &operator<<(OStream &OS, const RPCTypeNameSequence<ArgT> &V) {
-  OS << RPCTypeName<ArgT>::getName();
-  return OS;
-}
-
-/// Render a TypeNameSequence of more than one type to an ostream.
-template <typename OStream, typename ArgT1, typename ArgT2, typename... ArgTs>
-OStream&
-operator<<(OStream &OS, const RPCTypeNameSequence<ArgT1, ArgT2, ArgTs...> &V) {
-  OS << RPCTypeName<ArgT1>::getName() << ", "
-     << RPCTypeNameSequence<ArgT2, ArgTs...>();
-  return OS;
-}
-
-template <>
-class RPCTypeName<void> {
-public:
-  static const char* getName() { return "void"; }
-};
-
-template <>
-class RPCTypeName<int8_t> {
-public:
-  static const char* getName() { return "int8_t"; }
-};
-
-template <>
-class RPCTypeName<uint8_t> {
-public:
-  static const char* getName() { return "uint8_t"; }
-};
-
-template <>
-class RPCTypeName<int16_t> {
-public:
-  static const char* getName() { return "int16_t"; }
-};
-
-template <>
-class RPCTypeName<uint16_t> {
-public:
-  static const char* getName() { return "uint16_t"; }
-};
-
-template <>
-class RPCTypeName<int32_t> {
-public:
-  static const char* getName() { return "int32_t"; }
-};
-
-template <>
-class RPCTypeName<uint32_t> {
-public:
-  static const char* getName() { return "uint32_t"; }
-};
-
-template <>
-class RPCTypeName<int64_t> {
-public:
-  static const char* getName() { return "int64_t"; }
-};
-
-template <>
-class RPCTypeName<uint64_t> {
-public:
-  static const char* getName() { return "uint64_t"; }
-};
-
-template <>
-class RPCTypeName<bool> {
-public:
-  static const char* getName() { return "bool"; }
-};
-
-template <>
-class RPCTypeName<std::string> {
-public:
-  static const char* getName() { return "std::string"; }
-};
-
-template <>
-class RPCTypeName<Error> {
-public:
-  static const char* getName() { return "Error"; }
-};
-
-template <typename T>
-class RPCTypeName<Expected<T>> {
-public:
-  static const char* getName() {
-    static std::string Name = [] {
-      std::string Name;
-      raw_string_ostream(Name) << "Expected<"
-                               << RPCTypeNameSequence<T>()
-                               << ">";
-      return Name;
-    }();
-    return Name.data();
-  }
-};
-
-template <typename T1, typename T2>
-class RPCTypeName<std::pair<T1, T2>> {
-public:
-  static const char* getName() {
-    static std::string Name = [] {
-      std::string Name;
-      raw_string_ostream(Name) << "std::pair<" << RPCTypeNameSequence<T1, T2>()
-                               << ">";
-      return Name;
-    }();
-    return Name.data();
-  }
-};
-
-template <typename... ArgTs>
-class RPCTypeName<std::tuple<ArgTs...>> {
-public:
-  static const char* getName() {
-    static std::string Name = [] {
-      std::string Name;
-      raw_string_ostream(Name) << "std::tuple<"
-                               << RPCTypeNameSequence<ArgTs...>() << ">";
-      return Name;
-    }();
-    return Name.data();
-  }
-};
-
-template <typename T>
-class RPCTypeName<std::vector<T>> {
-public:
-  static const char*getName() {
-    static std::string Name = [] {
-      std::string Name;
-      raw_string_ostream(Name) << "std::vector<" << RPCTypeName<T>::getName()
-                               << ">";
-      return Name;
-    }();
-    return Name.data();
-  }
-};
-
-template <typename T> class RPCTypeName<std::set<T>> {
-public:
-  static const char *getName() {
-    static std::string Name = [] {
-      std::string Name;
-      raw_string_ostream(Name)
-          << "std::set<" << RPCTypeName<T>::getName() << ">";
-      return Name;
-    }();
-    return Name.data();
-  }
-};
-
-template <typename K, typename V> class RPCTypeName<std::map<K, V>> {
-public:
-  static const char *getName() {
-    static std::string Name = [] {
-      std::string Name;
-      raw_string_ostream(Name)
-          << "std::map<" << RPCTypeNameSequence<K, V>() << ">";
-      return Name;
-    }();
-    return Name.data();
-  }
-};
-
-/// The SerializationTraits<ChannelT, T> class describes how to serialize and
-/// deserialize an instance of type T to/from an abstract channel of type
-/// ChannelT. It also provides a representation of the type's name via the
-/// getName method.
-///
-/// Specializations of this class should provide the following functions:
-///
-///   @code{.cpp}
-///
-///   static const char* getName();
-///   static Error serialize(ChannelT&, const T&);
-///   static Error deserialize(ChannelT&, T&);
-///
-///   @endcode
-///
-/// The third argument of SerializationTraits is intended to support SFINAE.
-/// E.g.:
-///
-///   @code{.cpp}
-///
-///   class MyVirtualChannel { ... };
-///
-///   template <DerivedChannelT>
-///   class SerializationTraits<DerivedChannelT, bool,
-///         typename std::enable_if<
-///           std::is_base_of<VirtChannel, DerivedChannel>::value
-///         >::type> {
-///   public:
-///     static const char* getName() { ... };
-///   }
-///
-///   @endcode
-template <typename ChannelT, typename WireType,
-          typename ConcreteType = WireType, typename = void>
-class SerializationTraits;
-
-template <typename ChannelT>
-class SequenceTraits {
-public:
-  static Error emitSeparator(ChannelT &C) { return Error::success(); }
-  static Error consumeSeparator(ChannelT &C) { return Error::success(); }
-};
-
-/// Utility class for serializing sequences of values of varying types.
-/// Specializations of this class contain 'serialize' and 'deserialize' methods
-/// for the given channel. The ArgTs... list will determine the "over-the-wire"
-/// types to be serialized. The serialize and deserialize methods take a list
-/// CArgTs... ("caller arg types") which must be the same length as ArgTs...,
-/// but may be different types from ArgTs, provided that for each CArgT there
-/// is a SerializationTraits specialization
-/// SerializeTraits<ChannelT, ArgT, CArgT> with methods that can serialize the
-/// caller argument to over-the-wire value.
-template <typename ChannelT, typename... ArgTs>
-class SequenceSerialization;
-
-template <typename ChannelT>
-class SequenceSerialization<ChannelT> {
-public:
-  static Error serialize(ChannelT &C) { return Error::success(); }
-  static Error deserialize(ChannelT &C) { return Error::success(); }
-};
-
-template <typename ChannelT, typename ArgT>
-class SequenceSerialization<ChannelT, ArgT> {
-public:
-
-  template <typename CArgT>
-  static Error serialize(ChannelT &C, CArgT &&CArg) {
-    return SerializationTraits<ChannelT, ArgT,
-                               typename std::decay<CArgT>::type>::
-             serialize(C, std::forward<CArgT>(CArg));
-  }
-
-  template <typename CArgT>
-  static Error deserialize(ChannelT &C, CArgT &CArg) {
-    return SerializationTraits<ChannelT, ArgT, CArgT>::deserialize(C, CArg);
-  }
-};
-
-template <typename ChannelT, typename ArgT, typename... ArgTs>
-class SequenceSerialization<ChannelT, ArgT, ArgTs...> {
-public:
-
-  template <typename CArgT, typename... CArgTs>
-  static Error serialize(ChannelT &C, CArgT &&CArg,
-                         CArgTs &&... CArgs) {
-    if (auto Err =
-        SerializationTraits<ChannelT, ArgT, typename std::decay<CArgT>::type>::
-          serialize(C, std::forward<CArgT>(CArg)))
-      return Err;
-    if (auto Err = SequenceTraits<ChannelT>::emitSeparator(C))
-      return Err;
-    return SequenceSerialization<ChannelT, ArgTs...>::
-             serialize(C, std::forward<CArgTs>(CArgs)...);
-  }
-
-  template <typename CArgT, typename... CArgTs>
-  static Error deserialize(ChannelT &C, CArgT &CArg,
-                           CArgTs &... CArgs) {
-    if (auto Err =
-        SerializationTraits<ChannelT, ArgT, CArgT>::deserialize(C, CArg))
-      return Err;
-    if (auto Err = SequenceTraits<ChannelT>::consumeSeparator(C))
-      return Err;
-    return SequenceSerialization<ChannelT, ArgTs...>::deserialize(C, CArgs...);
-  }
-};
-
-template <typename ChannelT, typename... ArgTs>
-Error serializeSeq(ChannelT &C, ArgTs &&... Args) {
-  return SequenceSerialization<ChannelT, typename std::decay<ArgTs>::type...>::
-           serialize(C, std::forward<ArgTs>(Args)...);
-}
-
-template <typename ChannelT, typename... ArgTs>
-Error deserializeSeq(ChannelT &C, ArgTs &... Args) {
-  return SequenceSerialization<ChannelT, ArgTs...>::deserialize(C, Args...);
-}
-
-template <typename ChannelT>
-class SerializationTraits<ChannelT, Error> {
-public:
-
-  using WrappedErrorSerializer =
-    std::function<Error(ChannelT &C, const ErrorInfoBase&)>;
-
-  using WrappedErrorDeserializer =
-    std::function<Error(ChannelT &C, Error &Err)>;
-
-  template <typename ErrorInfoT, typename SerializeFtor,
-            typename DeserializeFtor>
-  static void registerErrorType(std::string Name, SerializeFtor Serialize,
-                                DeserializeFtor Deserialize) {
-    assert(!Name.empty() &&
-           "The empty string is reserved for the Success value");
-
-    const std::string *KeyName = nullptr;
-    {
-      // We're abusing the stability of std::map here: We take a reference to the
-      // key of the deserializers map to save us from duplicating the string in
-      // the serializer. This should be changed to use a stringpool if we switch
-      // to a map type that may move keys in memory.
-      std::lock_guard<std::recursive_mutex> Lock(DeserializersMutex);
-      auto I =
-        Deserializers.insert(Deserializers.begin(),
-                             std::make_pair(std::move(Name),
-                                            std::move(Deserialize)));
-      KeyName = &I->first;
-    }
-
-    {
-      assert(KeyName != nullptr && "No keyname pointer");
-      std::lock_guard<std::recursive_mutex> Lock(SerializersMutex);
-      Serializers[ErrorInfoT::classID()] =
-          [KeyName, Serialize = std::move(Serialize)](
-              ChannelT &C, const ErrorInfoBase &EIB) -> Error {
-        assert(EIB.dynamicClassID() == ErrorInfoT::classID() &&
-               "Serializer called for wrong error type");
-        if (auto Err = serializeSeq(C, *KeyName))
-          return Err;
-        return Serialize(C, static_cast<const ErrorInfoT &>(EIB));
-      };
-    }
-  }
-
-  static Error serialize(ChannelT &C, Error &&Err) {
-    std::lock_guard<std::recursive_mutex> Lock(SerializersMutex);
-
-    if (!Err)
-      return serializeSeq(C, std::string());
-
-    return handleErrors(std::move(Err),
-                        [&C](const ErrorInfoBase &EIB) {
-                          auto SI = Serializers.find(EIB.dynamicClassID());
-                          if (SI == Serializers.end())
-                            return serializeAsStringError(C, EIB);
-                          return (SI->second)(C, EIB);
-                        });
-  }
-
-  static Error deserialize(ChannelT &C, Error &Err) {
-    std::lock_guard<std::recursive_mutex> Lock(DeserializersMutex);
-
-    std::string Key;
-    if (auto Err = deserializeSeq(C, Key))
-      return Err;
-
-    if (Key.empty()) {
-      ErrorAsOutParameter EAO(&Err);
-      Err = Error::success();
-      return Error::success();
-    }
-
-    auto DI = Deserializers.find(Key);
-    assert(DI != Deserializers.end() && "No deserializer for error type");
-    return (DI->second)(C, Err);
-  }
-
-private:
-
-  static Error serializeAsStringError(ChannelT &C, const ErrorInfoBase &EIB) {
-    std::string ErrMsg;
-    {
-      raw_string_ostream ErrMsgStream(ErrMsg);
-      EIB.log(ErrMsgStream);
-    }
-    return serialize(C, make_error<StringError>(std::move(ErrMsg),
-                                                inconvertibleErrorCode()));
-  }
-
-  static std::recursive_mutex SerializersMutex;
-  static std::recursive_mutex DeserializersMutex;
-  static std::map<const void*, WrappedErrorSerializer> Serializers;
-  static std::map<std::string, WrappedErrorDeserializer> Deserializers;
-};
-
-template <typename ChannelT>
-std::recursive_mutex SerializationTraits<ChannelT, Error>::SerializersMutex;
-
-template <typename ChannelT>
-std::recursive_mutex SerializationTraits<ChannelT, Error>::DeserializersMutex;
-
-template <typename ChannelT>
-std::map<const void*,
-         typename SerializationTraits<ChannelT, Error>::WrappedErrorSerializer>
-SerializationTraits<ChannelT, Error>::Serializers;
-
-template <typename ChannelT>
-std::map<std::string,
-         typename SerializationTraits<ChannelT, Error>::WrappedErrorDeserializer>
-SerializationTraits<ChannelT, Error>::Deserializers;
-
-/// Registers a serializer and deserializer for the given error type on the
-/// given channel type.
-template <typename ChannelT, typename ErrorInfoT, typename SerializeFtor,
-          typename DeserializeFtor>
-void registerErrorSerialization(std::string Name, SerializeFtor &&Serialize,
-                                DeserializeFtor &&Deserialize) {
-  SerializationTraits<ChannelT, Error>::template registerErrorType<ErrorInfoT>(
-    std::move(Name),
-    std::forward<SerializeFtor>(Serialize),
-    std::forward<DeserializeFtor>(Deserialize));
-}
-
-/// Registers serialization/deserialization for StringError.
-template <typename ChannelT>
-void registerStringError() {
-  static bool AlreadyRegistered = false;
-  if (!AlreadyRegistered) {
-    registerErrorSerialization<ChannelT, StringError>(
-      "StringError",
-      [](ChannelT &C, const StringError &SE) {
-        return serializeSeq(C, SE.getMessage());
-      },
-      [](ChannelT &C, Error &Err) -> Error {
-        ErrorAsOutParameter EAO(&Err);
-        std::string Msg;
-        if (auto E2 = deserializeSeq(C, Msg))
-          return E2;
-        Err =
-          make_error<StringError>(std::move(Msg),
-                                  orcError(
-                                    OrcErrorCode::UnknownErrorCodeFromRemote));
-        return Error::success();
-      });
-    AlreadyRegistered = true;
-  }
-}
-
-/// SerializationTraits for Expected<T1> from an Expected<T2>.
-template <typename ChannelT, typename T1, typename T2>
-class SerializationTraits<ChannelT, Expected<T1>, Expected<T2>> {
-public:
-
-  static Error serialize(ChannelT &C, Expected<T2> &&ValOrErr) {
-    if (ValOrErr) {
-      if (auto Err = serializeSeq(C, true))
-        return Err;
-      return SerializationTraits<ChannelT, T1, T2>::serialize(C, *ValOrErr);
-    }
-    if (auto Err = serializeSeq(C, false))
-      return Err;
-    return serializeSeq(C, ValOrErr.takeError());
-  }
-
-  static Error deserialize(ChannelT &C, Expected<T2> &ValOrErr) {
-    ExpectedAsOutParameter<T2> EAO(&ValOrErr);
-    bool HasValue;
-    if (auto Err = deserializeSeq(C, HasValue))
-      return Err;
-    if (HasValue)
-      return SerializationTraits<ChannelT, T1, T2>::deserialize(C, *ValOrErr);
-    Error Err = Error::success();
-    if (auto E2 = deserializeSeq(C, Err))
-      return E2;
-    ValOrErr = std::move(Err);
-    return Error::success();
-  }
-};
-
-/// SerializationTraits for Expected<T1> from a T2.
-template <typename ChannelT, typename T1, typename T2>
-class SerializationTraits<ChannelT, Expected<T1>, T2> {
-public:
-
-  static Error serialize(ChannelT &C, T2 &&Val) {
-    return serializeSeq(C, Expected<T2>(std::forward<T2>(Val)));
-  }
-};
-
-/// SerializationTraits for Expected<T1> from an Error.
-template <typename ChannelT, typename T>
-class SerializationTraits<ChannelT, Expected<T>, Error> {
-public:
-
-  static Error serialize(ChannelT &C, Error &&Err) {
-    return serializeSeq(C, Expected<T>(std::move(Err)));
-  }
-};
-
-/// SerializationTraits default specialization for std::pair.
-template <typename ChannelT, typename T1, typename T2, typename T3, typename T4>
-class SerializationTraits<ChannelT, std::pair<T1, T2>, std::pair<T3, T4>> {
-public:
-  static Error serialize(ChannelT &C, const std::pair<T3, T4> &V) {
-    if (auto Err = SerializationTraits<ChannelT, T1, T3>::serialize(C, V.first))
-      return Err;
-    return SerializationTraits<ChannelT, T2, T4>::serialize(C, V.second);
-  }
-
-  static Error deserialize(ChannelT &C, std::pair<T3, T4> &V) {
-    if (auto Err =
-            SerializationTraits<ChannelT, T1, T3>::deserialize(C, V.first))
-      return Err;
-    return SerializationTraits<ChannelT, T2, T4>::deserialize(C, V.second);
-  }
-};
-
-/// SerializationTraits default specialization for std::tuple.
-template <typename ChannelT, typename... ArgTs>
-class SerializationTraits<ChannelT, std::tuple<ArgTs...>> {
-public:
-
-  /// RPC channel serialization for std::tuple.
-  static Error serialize(ChannelT &C, const std::tuple<ArgTs...> &V) {
-    return serializeTupleHelper(C, V, std::index_sequence_for<ArgTs...>());
-  }
-
-  /// RPC channel deserialization for std::tuple.
-  static Error deserialize(ChannelT &C, std::tuple<ArgTs...> &V) {
-    return deserializeTupleHelper(C, V, std::index_sequence_for<ArgTs...>());
-  }
-
-private:
-  // Serialization helper for std::tuple.
-  template <size_t... Is>
-  static Error serializeTupleHelper(ChannelT &C, const std::tuple<ArgTs...> &V,
-                                    std::index_sequence<Is...> _) {
-    return serializeSeq(C, std::get<Is>(V)...);
-  }
-
-  // Serialization helper for std::tuple.
-  template <size_t... Is>
-  static Error deserializeTupleHelper(ChannelT &C, std::tuple<ArgTs...> &V,
-                                      std::index_sequence<Is...> _) {
-    return deserializeSeq(C, std::get<Is>(V)...);
-  }
-};
-
-/// SerializationTraits default specialization for std::vector.
-template <typename ChannelT, typename T>
-class SerializationTraits<ChannelT, std::vector<T>> {
-public:
-
-  /// Serialize a std::vector<T> from std::vector<T>.
-  static Error serialize(ChannelT &C, const std::vector<T> &V) {
-    if (auto Err = serializeSeq(C, static_cast<uint64_t>(V.size())))
-      return Err;
-
-    for (const auto &E : V)
-      if (auto Err = serializeSeq(C, E))
-        return Err;
-
-    return Error::success();
-  }
-
-  /// Deserialize a std::vector<T> to a std::vector<T>.
-  static Error deserialize(ChannelT &C, std::vector<T> &V) {
-    assert(V.empty() &&
-           "Expected default-constructed vector to deserialize into");
-
-    uint64_t Count = 0;
-    if (auto Err = deserializeSeq(C, Count))
-      return Err;
-
-    V.resize(Count);
-    for (auto &E : V)
-      if (auto Err = deserializeSeq(C, E))
-        return Err;
-
-    return Error::success();
-  }
-};
-
-template <typename ChannelT, typename T, typename T2>
-class SerializationTraits<ChannelT, std::set<T>, std::set<T2>> {
-public:
-  /// Serialize a std::set<T> from std::set<T2>.
-  static Error serialize(ChannelT &C, const std::set<T2> &S) {
-    if (auto Err = serializeSeq(C, static_cast<uint64_t>(S.size())))
-      return Err;
-
-    for (const auto &E : S)
-      if (auto Err = SerializationTraits<ChannelT, T, T2>::serialize(C, E))
-        return Err;
-
-    return Error::success();
-  }
-
-  /// Deserialize a std::set<T> to a std::set<T>.
-  static Error deserialize(ChannelT &C, std::set<T2> &S) {
-    assert(S.empty() && "Expected default-constructed set to deserialize into");
-
-    uint64_t Count = 0;
-    if (auto Err = deserializeSeq(C, Count))
-      return Err;
-
-    while (Count-- != 0) {
-      T2 Val;
-      if (auto Err = SerializationTraits<ChannelT, T, T2>::deserialize(C, Val))
-        return Err;
-
-      auto Added = S.insert(Val).second;
-      if (!Added)
-        return make_error<StringError>("Duplicate element in deserialized set",
-                                       orcError(OrcErrorCode::UnknownORCError));
-    }
-
-    return Error::success();
-  }
-};
-
-template <typename ChannelT, typename K, typename V, typename K2, typename V2>
-class SerializationTraits<ChannelT, std::map<K, V>, std::map<K2, V2>> {
-public:
-  /// Serialize a std::map<K, V> from std::map<K2, V2>.
-  static Error serialize(ChannelT &C, const std::map<K2, V2> &M) {
-    if (auto Err = serializeSeq(C, static_cast<uint64_t>(M.size())))
-      return Err;
-
-    for (const auto &E : M) {
-      if (auto Err =
-              SerializationTraits<ChannelT, K, K2>::serialize(C, E.first))
-        return Err;
-      if (auto Err =
-              SerializationTraits<ChannelT, V, V2>::serialize(C, E.second))
-        return Err;
-    }
-
-    return Error::success();
-  }
-
-  /// Deserialize a std::map<K, V> to a std::map<K, V>.
-  static Error deserialize(ChannelT &C, std::map<K2, V2> &M) {
-    assert(M.empty() && "Expected default-constructed map to deserialize into");
-
-    uint64_t Count = 0;
-    if (auto Err = deserializeSeq(C, Count))
-      return Err;
-
-    while (Count-- != 0) {
-      std::pair<K2, V2> Val;
-      if (auto Err =
-              SerializationTraits<ChannelT, K, K2>::deserialize(C, Val.first))
-        return Err;
-
-      if (auto Err =
-              SerializationTraits<ChannelT, V, V2>::deserialize(C, Val.second))
-        return Err;
-
-      auto Added = M.insert(Val).second;
-      if (!Added)
-        return make_error<StringError>("Duplicate element in deserialized map",
-                                       orcError(OrcErrorCode::UnknownORCError));
-    }
-
-    return Error::success();
-  }
-};
-
-} // end namespace rpc
-} // end namespace orc
-} // end namespace llvm
-
-#endif // LLVM_EXECUTIONENGINE_ORC_RPCSERIALIZATION_H
diff --git a/llvm/include/llvm/ExecutionEngine/Orc/RPCUtils.h b/llvm/include/llvm/ExecutionEngine/Orc/RPCUtils.h
deleted file mode 100644
index ee9c2cc69c3..00000000000
--- a/llvm/include/llvm/ExecutionEngine/Orc/RPCUtils.h
+++ /dev/null
@@ -1,1690 +0,0 @@
-//===- RPCUtils.h - Utilities for building RPC APIs -------------*- 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
-//
-//===----------------------------------------------------------------------===//
-//
-// Utilities to support construction of simple RPC APIs.
-//
-// The RPC utilities aim for ease of use (minimal conceptual overhead) for C++
-// programmers, high performance, low memory overhead, and efficient use of the
-// communications channel.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_EXECUTIONENGINE_ORC_RPCUTILS_H
-#define LLVM_EXECUTIONENGINE_ORC_RPCUTILS_H
-
-#include <map>
-#include <thread>
-#include <vector>
-
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ExecutionEngine/Orc/OrcError.h"
-#include "llvm/ExecutionEngine/Orc/RPCSerialization.h"
-#include "llvm/Support/MSVCErrorWorkarounds.h"
-
-#include <future>
-
-namespace llvm {
-namespace orc {
-namespace rpc {
-
-/// Base class of all fatal RPC errors (those that necessarily result in the
-/// termination of the RPC session).
-class RPCFatalError : public ErrorInfo<RPCFatalError> {
-public:
-  static char ID;
-};
-
-/// RPCConnectionClosed is returned from RPC operations if the RPC connection
-/// has already been closed due to either an error or graceful disconnection.
-class ConnectionClosed : public ErrorInfo<ConnectionClosed> {
-public:
-  static char ID;
-  std::error_code convertToErrorCode() const override;
-  void log(raw_ostream &OS) const override;
-};
-
-/// BadFunctionCall is returned from handleOne when the remote makes a call with
-/// an unrecognized function id.
-///
-/// This error is fatal because Orc RPC needs to know how to parse a function
-/// call to know where the next call starts, and if it doesn't recognize the
-/// function id it cannot parse the call.
-template <typename FnIdT, typename SeqNoT>
-class BadFunctionCall
-  : public ErrorInfo<BadFunctionCall<FnIdT, SeqNoT>, RPCFatalError> {
-public:
-  static char ID;
-
-  BadFunctionCall(FnIdT FnId, SeqNoT SeqNo)
-      : FnId(std::move(FnId)), SeqNo(std::move(SeqNo)) {}
-
-  std::error_code convertToErrorCode() const override {
-    return orcError(OrcErrorCode::UnexpectedRPCCall);
-  }
-
-  void log(raw_ostream &OS) const override {
-    OS << "Call to invalid RPC function id '" << FnId << "' with "
-          "sequence number " << SeqNo;
-  }
-
-private:
-  FnIdT FnId;
-  SeqNoT SeqNo;
-};
-
-template <typename FnIdT, typename SeqNoT>
-char BadFunctionCall<FnIdT, SeqNoT>::ID = 0;
-
-/// InvalidSequenceNumberForResponse is returned from handleOne when a response
-/// call arrives with a sequence number that doesn't correspond to any in-flight
-/// function call.
-///
-/// This error is fatal because Orc RPC needs to know how to parse the rest of
-/// the response call to know where the next call starts, and if it doesn't have
-/// a result parser for this sequence number it can't do that.
-template <typename SeqNoT>
-class InvalidSequenceNumberForResponse
-    : public ErrorInfo<InvalidSequenceNumberForResponse<SeqNoT>, RPCFatalError> {
-public:
-  static char ID;
-
-  InvalidSequenceNumberForResponse(SeqNoT SeqNo)
-      : SeqNo(std::move(SeqNo)) {}
-
-  std::error_code convertToErrorCode() const override {
-    return orcError(OrcErrorCode::UnexpectedRPCCall);
-  };
-
-  void log(raw_ostream &OS) const override {
-    OS << "Response has unknown sequence number " << SeqNo;
-  }
-private:
-  SeqNoT SeqNo;
-};
-
-template <typename SeqNoT>
-char InvalidSequenceNumberForResponse<SeqNoT>::ID = 0;
-
-/// This non-fatal error will be passed to asynchronous result handlers in place
-/// of a result if the connection goes down before a result returns, or if the
-/// function to be called cannot be negotiated with the remote.
-class ResponseAbandoned : public ErrorInfo<ResponseAbandoned> {
-public:
-  static char ID;
-
-  std::error_code convertToErrorCode() const override;
-  void log(raw_ostream &OS) const override;
-};
-
-/// This error is returned if the remote does not have a handler installed for
-/// the given RPC function.
-class CouldNotNegotiate : public ErrorInfo<CouldNotNegotiate> {
-public:
-  static char ID;
-
-  CouldNotNegotiate(std::string Signature);
-  std::error_code convertToErrorCode() const override;
-  void log(raw_ostream &OS) const override;
-  const std::string &getSignature() const { return Signature; }
-private:
-  std::string Signature;
-};
-
-template <typename DerivedFunc, typename FnT> class Function;
-
-// RPC Function class.
-// DerivedFunc should be a user defined class with a static 'getName()' method
-// returning a const char* representing the function's name.
-template <typename DerivedFunc, typename RetT, typename... ArgTs>
-class Function<DerivedFunc, RetT(ArgTs...)> {
-public:
-  /// User defined function type.
-  using Type = RetT(ArgTs...);
-
-  /// Return type.
-  using ReturnType = RetT;
-
-  /// Returns the full function prototype as a string.
-  static const char *getPrototype() {
-    static std::string Name = [] {
-      std::string Name;
-      raw_string_ostream(Name)
-          << RPCTypeName<RetT>::getName() << " " << DerivedFunc::getName()
-          << "(" << llvm::orc::rpc::RPCTypeNameSequence<ArgTs...>() << ")";
-      return Name;
-    }();
-    return Name.data();
-  }
-};
-
-/// Allocates RPC function ids during autonegotiation.
-/// Specializations of this class must provide four members:
-///
-/// static T getInvalidId():
-///   Should return a reserved id that will be used to represent missing
-/// functions during autonegotiation.
-///
-/// static T getResponseId():
-///   Should return a reserved id that will be used to send function responses
-/// (return values).
-///
-/// static T getNegotiateId():
-///   Should return a reserved id for the negotiate function, which will be used
-/// to negotiate ids for user defined functions.
-///
-/// template <typename Func> T allocate():
-///   Allocate a unique id for function Func.
-template <typename T, typename = void> class RPCFunctionIdAllocator;
-
-/// This specialization of RPCFunctionIdAllocator provides a default
-/// implementation for integral types.
-template <typename T>
-class RPCFunctionIdAllocator<
-    T, typename std::enable_if<std::is_integral<T>::value>::type> {
-public:
-  static T getInvalidId() { return T(0); }
-  static T getResponseId() { return T(1); }
-  static T getNegotiateId() { return T(2); }
-
-  template <typename Func> T allocate() { return NextId++; }
-
-private:
-  T NextId = 3;
-};
-
-namespace detail {
-
-/// Provides a typedef for a tuple containing the decayed argument types.
-template <typename T> class FunctionArgsTuple;
-
-template <typename RetT, typename... ArgTs>
-class FunctionArgsTuple<RetT(ArgTs...)> {
-public:
-  using Type = std::tuple<typename std::decay<
-      typename std::remove_reference<ArgTs>::type>::type...>;
-};
-
-// ResultTraits provides typedefs and utilities specific to the return type
-// of functions.
-template <typename RetT> class ResultTraits {
-public:
-  // The return type wrapped in llvm::Expected.
-  using ErrorReturnType = Expected<RetT>;
-
-#ifdef _MSC_VER
-  // The ErrorReturnType wrapped in a std::promise.
-  using ReturnPromiseType = std::promise<MSVCPExpected<RetT>>;
-
-  // The ErrorReturnType wrapped in a std::future.
-  using ReturnFutureType = std::future<MSVCPExpected<RetT>>;
-#else
-  // The ErrorReturnType wrapped in a std::promise.
-  using ReturnPromiseType = std::promise<ErrorReturnType>;
-
-  // The ErrorReturnType wrapped in a std::future.
-  using ReturnFutureType = std::future<ErrorReturnType>;
-#endif
-
-  // Create a 'blank' value of the ErrorReturnType, ready and safe to
-  // overwrite.
-  static ErrorReturnType createBlankErrorReturnValue() {
-    return ErrorReturnType(RetT());
-  }
-
-  // Consume an abandoned ErrorReturnType.
-  static void consumeAbandoned(ErrorReturnType RetOrErr) {
-    consumeError(RetOrErr.takeError());
-  }
-};
-
-// ResultTraits specialization for void functions.
-template <> class ResultTraits<void> {
-public:
-  // For void functions, ErrorReturnType is llvm::Error.
-  using ErrorReturnType = Error;
-
-#ifdef _MSC_VER
-  // The ErrorReturnType wrapped in a std::promise.
-  using ReturnPromiseType = std::promise<MSVCPError>;
-
-  // The ErrorReturnType wrapped in a std::future.
-  using ReturnFutureType = std::future<MSVCPError>;
-#else
-  // The ErrorReturnType wrapped in a std::promise.
-  using ReturnPromiseType = std::promise<ErrorReturnType>;
-
-  // The ErrorReturnType wrapped in a std::future.
-  using ReturnFutureType = std::future<ErrorReturnType>;
-#endif
-
-  // Create a 'blank' value of the ErrorReturnType, ready and safe to
-  // overwrite.
-  static ErrorReturnType createBlankErrorReturnValue() {
-    return ErrorReturnType::success();
-  }
-
-  // Consume an abandoned ErrorReturnType.
-  static void consumeAbandoned(ErrorReturnType Err) {
-    consumeError(std::move(Err));
-  }
-};
-
-// ResultTraits<Error> is equivalent to ResultTraits<void>. This allows
-// handlers for void RPC functions to return either void (in which case they
-// implicitly succeed) or Error (in which case their error return is
-// propagated). See usage in HandlerTraits::runHandlerHelper.
-template <> class ResultTraits<Error> : public ResultTraits<void> {};
-
-// ResultTraits<Expected<T>> is equivalent to ResultTraits<T>. This allows
-// handlers for RPC functions returning a T to return either a T (in which
-// case they implicitly succeed) or Expected<T> (in which case their error
-// return is propagated). See usage in HandlerTraits::runHandlerHelper.
-template <typename RetT>
-class ResultTraits<Expected<RetT>> : public ResultTraits<RetT> {};
-
-// Determines whether an RPC function's defined error return type supports
-// error return value.
-template <typename T>
-class SupportsErrorReturn {
-public:
-  static const bool value = false;
-};
-
-template <>
-class SupportsErrorReturn<Error> {
-public:
-  static const bool value = true;
-};
-
-template <typename T>
-class SupportsErrorReturn<Expected<T>> {
-public:
-  static const bool value = true;
-};
-
-// RespondHelper packages return values based on whether or not the declared
-// RPC function return type supports error returns.
-template <bool FuncSupportsErrorReturn>
-class RespondHelper;
-
-// RespondHelper specialization for functions that support error returns.
-template <>
-class RespondHelper<true> {
-public:
-
-  // Send Expected<T>.
-  template <typename WireRetT, typename HandlerRetT, typename ChannelT,
-            typename FunctionIdT, typename SequenceNumberT>
-  static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
-                          SequenceNumberT SeqNo,
-                          Expected<HandlerRetT> ResultOrErr) {
-    if (!ResultOrErr && ResultOrErr.template errorIsA<RPCFatalError>())
-      return ResultOrErr.takeError();
-
-    // Open the response message.
-    if (auto Err = C.startSendMessage(ResponseId, SeqNo))
-      return Err;
-
-    // Serialize the result.
-    if (auto Err =
-        SerializationTraits<ChannelT, WireRetT,
-                            Expected<HandlerRetT>>::serialize(
-                                                     C, std::move(ResultOrErr)))
-      return Err;
-
-    // Close the response message.
-    if (auto Err = C.endSendMessage())
-      return Err;
-    return C.send();
-  }
-
-  template <typename ChannelT, typename FunctionIdT, typename SequenceNumberT>
-  static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
-                          SequenceNumberT SeqNo, Error Err) {
-    if (Err && Err.isA<RPCFatalError>())
-      return Err;
-    if (auto Err2 = C.startSendMessage(ResponseId, SeqNo))
-      return Err2;
-    if (auto Err2 = serializeSeq(C, std::move(Err)))
-      return Err2;
-    if (auto Err2 = C.endSendMessage())
-      return Err2;
-    return C.send();
-  }
-
-};
-
-// RespondHelper specialization for functions that do not support error returns.
-template <>
-class RespondHelper<false> {
-public:
-
-  template <typename WireRetT, typename HandlerRetT, typename ChannelT,
-            typename FunctionIdT, typename SequenceNumberT>
-  static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
-                          SequenceNumberT SeqNo,
-                          Expected<HandlerRetT> ResultOrErr) {
-    if (auto Err = ResultOrErr.takeError())
-      return Err;
-
-    // Open the response message.
-    if (auto Err = C.startSendMessage(ResponseId, SeqNo))
-      return Err;
-
-    // Serialize the result.
-    if (auto Err =
-        SerializationTraits<ChannelT, WireRetT, HandlerRetT>::serialize(
-                                                               C, *ResultOrErr))
-      return Err;
-
-    // End the response message.
-    if (auto Err = C.endSendMessage())
-      return Err;
-
-    return C.send();
-  }
-
-  template <typename ChannelT, typename FunctionIdT, typename SequenceNumberT>
-  static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
-                          SequenceNumberT SeqNo, Error Err) {
-    if (Err)
-      return Err;
-    if (auto Err2 = C.startSendMessage(ResponseId, SeqNo))
-      return Err2;
-    if (auto Err2 = C.endSendMessage())
-      return Err2;
-    return C.send();
-  }
-
-};
-
-
-// Send a response of the given wire return type (WireRetT) over the
-// channel, with the given sequence number.
-template <typename WireRetT, typename HandlerRetT, typename ChannelT,
-          typename FunctionIdT, typename SequenceNumberT>
-Error respond(ChannelT &C, const FunctionIdT &ResponseId,
-              SequenceNumberT SeqNo, Expected<HandlerRetT> ResultOrErr) {
-  return RespondHelper<SupportsErrorReturn<WireRetT>::value>::
-    template sendResult<WireRetT>(C, ResponseId, SeqNo, std::move(ResultOrErr));
-}
-
-// Send an empty response message on the given channel to indicate that
-// the handler ran.
-template <typename WireRetT, typename ChannelT, typename FunctionIdT,
-          typename SequenceNumberT>
-Error respond(ChannelT &C, const FunctionIdT &ResponseId, SequenceNumberT SeqNo,
-              Error Err) {
-  return RespondHelper<SupportsErrorReturn<WireRetT>::value>::
-    sendResult(C, ResponseId, SeqNo, std::move(Err));
-}
-
-// Converts a given type to the equivalent error return type.
-template <typename T> class WrappedHandlerReturn {
-public:
-  using Type = Expected<T>;
-};
-
-template <typename T> class WrappedHandlerReturn<Expected<T>> {
-public:
-  using Type = Expected<T>;
-};
-
-template <> class WrappedHandlerReturn<void> {
-public:
-  using Type = Error;
-};
-
-template <> class WrappedHandlerReturn<Error> {
-public:
-  using Type = Error;
-};
-
-template <> class WrappedHandlerReturn<ErrorSuccess> {
-public:
-  using Type = Error;
-};
-
-// Traits class that strips the response function from the list of handler
-// arguments.
-template <typename FnT> class AsyncHandlerTraits;
-
-template <typename ResultT, typename... ArgTs>
-class AsyncHandlerTraits<Error(std::function<Error(Expected<ResultT>)>, ArgTs...)> {
-public:
-  using Type = Error(ArgTs...);
-  using ResultType = Expected<ResultT>;
-};
-
-template <typename... ArgTs>
-class AsyncHandlerTraits<Error(std::function<Error(Error)>, ArgTs...)> {
-public:
-  using Type = Error(ArgTs...);
-  using ResultType = Error;
-};
-
-template <typename... ArgTs>
-class AsyncHandlerTraits<ErrorSuccess(std::function<Error(Error)>, ArgTs...)> {
-public:
-  using Type = Error(ArgTs...);
-  using ResultType = Error;
-};
-
-template <typename... ArgTs>
-class AsyncHandlerTraits<void(std::function<Error(Error)>, ArgTs...)> {
-public:
-  using Type = Error(ArgTs...);
-  using ResultType = Error;
-};
-
-template <typename ResponseHandlerT, typename... ArgTs>
-class AsyncHandlerTraits<Error(ResponseHandlerT, ArgTs...)> :
-    public AsyncHandlerTraits<Error(typename std::decay<ResponseHandlerT>::type,
-                                    ArgTs...)> {};
-
-// This template class provides utilities related to RPC function handlers.
-// The base case applies to non-function types (the template class is
-// specialized for function types) and inherits from the appropriate
-// speciilization for the given non-function type's call operator.
-template <typename HandlerT>
-class HandlerTraits : public HandlerTraits<decltype(
-                          &std::remove_reference<HandlerT>::type::operator())> {
-};
-
-// Traits for handlers with a given function type.
-template <typename RetT, typename... ArgTs>
-class HandlerTraits<RetT(ArgTs...)> {
-public:
-  // Function type of the handler.
-  using Type = RetT(ArgTs...);
-
-  // Return type of the handler.
-  using ReturnType = RetT;
-
-  // Call the given handler with the given arguments.
-  template <typename HandlerT, typename... TArgTs>
-  static typename WrappedHandlerReturn<RetT>::Type
-  unpackAndRun(HandlerT &Handler, std::tuple<TArgTs...> &Args) {
-    return unpackAndRunHelper(Handler, Args,
-                              std::index_sequence_for<TArgTs...>());
-  }
-
-  // Call the given handler with the given arguments.
-  template <typename HandlerT, typename ResponderT, typename... TArgTs>
-  static Error unpackAndRunAsync(HandlerT &Handler, ResponderT &Responder,
-                                 std::tuple<TArgTs...> &Args) {
-    return unpackAndRunAsyncHelper(Handler, Responder, Args,
-                                   std::index_sequence_for<TArgTs...>());
-  }
-
-  // Call the given handler with the given arguments.
-  template <typename HandlerT>
-  static typename std::enable_if<
-      std::is_void<typename HandlerTraits<HandlerT>::ReturnType>::value,
-      Error>::type
-  run(HandlerT &Handler, ArgTs &&... Args) {
-    Handler(std::move(Args)...);
-    return Error::success();
-  }
-
-  template <typename HandlerT, typename... TArgTs>
-  static typename std::enable_if<
-      !std::is_void<typename HandlerTraits<HandlerT>::ReturnType>::value,
-      typename HandlerTraits<HandlerT>::ReturnType>::type
-  run(HandlerT &Handler, TArgTs... Args) {
-    return Handler(std::move(Args)...);
-  }
-
-  // Serialize arguments to the channel.
-  template <typename ChannelT, typename... CArgTs>
-  static Error serializeArgs(ChannelT &C, const CArgTs... CArgs) {
-    return SequenceSerialization<ChannelT, ArgTs...>::serialize(C, CArgs...);
-  }
-
-  // Deserialize arguments from the channel.
-  template <typename ChannelT, typename... CArgTs>
-  static Error deserializeArgs(ChannelT &C, std::tuple<CArgTs...> &Args) {
-    return deserializeArgsHelper(C, Args, std::index_sequence_for<CArgTs...>());
-  }
-
-private:
-  template <typename ChannelT, typename... CArgTs, size_t... Indexes>
-  static Error deserializeArgsHelper(ChannelT &C, std::tuple<CArgTs...> &Args,
-                                     std::index_sequence<Indexes...> _) {
-    return SequenceSerialization<ChannelT, ArgTs...>::deserialize(
-        C, std::get<Indexes>(Args)...);
-  }
-
-  template <typename HandlerT, typename ArgTuple, size_t... Indexes>
-  static typename WrappedHandlerReturn<
-      typename HandlerTraits<HandlerT>::ReturnType>::Type
-  unpackAndRunHelper(HandlerT &Handler, ArgTuple &Args,
-                     std::index_sequence<Indexes...>) {
-    return run(Handler, std::move(std::get<Indexes>(Args))...);
-  }
-
-  template <typename HandlerT, typename ResponderT, typename ArgTuple,
-            size_t... Indexes>
-  static typename WrappedHandlerReturn<
-      typename HandlerTraits<HandlerT>::ReturnType>::Type
-  unpackAndRunAsyncHelper(HandlerT &Handler, ResponderT &Responder,
-                          ArgTuple &Args, std::index_sequence<Indexes...>) {
-    return run(Handler, Responder, std::move(std::get<Indexes>(Args))...);
-  }
-};
-
-// Handler traits for free functions.
-template <typename RetT, typename... ArgTs>
-class HandlerTraits<RetT(*)(ArgTs...)>
-  : public HandlerTraits<RetT(ArgTs...)> {};
-
-// Handler traits for class methods (especially call operators for lambdas).
-template <typename Class, typename RetT, typename... ArgTs>
-class HandlerTraits<RetT (Class::*)(ArgTs...)>
-    : public HandlerTraits<RetT(ArgTs...)> {};
-
-// Handler traits for const class methods (especially call operators for
-// lambdas).
-template <typename Class, typename RetT, typename... ArgTs>
-class HandlerTraits<RetT (Class::*)(ArgTs...) const>
-    : public HandlerTraits<RetT(ArgTs...)> {};
-
-// Utility to peel the Expected wrapper off a response handler error type.
-template <typename HandlerT> class ResponseHandlerArg;
-
-template <typename ArgT> class ResponseHandlerArg<Error(Expected<ArgT>)> {
-public:
-  using ArgType = Expected<ArgT>;
-  using UnwrappedArgType = ArgT;
-};
-
-template <typename ArgT>
-class ResponseHandlerArg<ErrorSuccess(Expected<ArgT>)> {
-public:
-  using ArgType = Expected<ArgT>;
-  using UnwrappedArgType = ArgT;
-};
-
-template <> class ResponseHandlerArg<Error(Error)> {
-public:
-  using ArgType = Error;
-};
-
-template <> class ResponseHandlerArg<ErrorSuccess(Error)> {
-public:
-  using ArgType = Error;
-};
-
-// ResponseHandler represents a handler for a not-yet-received function call
-// result.
-template <typename ChannelT> class ResponseHandler {
-public:
-  virtual ~ResponseHandler() {}
-
-  // Reads the function result off the wire and acts on it. The meaning of
-  // "act" will depend on how this method is implemented in any given
-  // ResponseHandler subclass but could, for example, mean running a
-  // user-specified handler or setting a promise value.
-  virtual Error handleResponse(ChannelT &C) = 0;
-
-  // Abandons this outstanding result.
-  virtual void abandon() = 0;
-
-  // Create an error instance representing an abandoned response.
-  static Error createAbandonedResponseError() {
-    return make_error<ResponseAbandoned>();
-  }
-};
-
-// ResponseHandler subclass for RPC functions with non-void returns.
-template <typename ChannelT, typename FuncRetT, typename HandlerT>
-class ResponseHandlerImpl : public ResponseHandler<ChannelT> {
-public:
-  ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
-
-  // Handle the result by deserializing it from the channel then passing it
-  // to the user defined handler.
-  Error handleResponse(ChannelT &C) override {
-    using UnwrappedArgType = typename ResponseHandlerArg<
-        typename HandlerTraits<HandlerT>::Type>::UnwrappedArgType;
-    UnwrappedArgType Result;
-    if (auto Err =
-            SerializationTraits<ChannelT, FuncRetT,
-                                UnwrappedArgType>::deserialize(C, Result))
-      return Err;
-    if (auto Err = C.endReceiveMessage())
-      return Err;
-    return Handler(std::move(Result));
-  }
-
-  // Abandon this response by calling the handler with an 'abandoned response'
-  // error.
-  void abandon() override {
-    if (auto Err = Handler(this->createAbandonedResponseError())) {
-      // Handlers should not fail when passed an abandoned response error.
-      report_fatal_error(std::move(Err));
-    }
-  }
-
-private:
-  HandlerT Handler;
-};
-
-// ResponseHandler subclass for RPC functions with void returns.
-template <typename ChannelT, typename HandlerT>
-class ResponseHandlerImpl<ChannelT, void, HandlerT>
-    : public ResponseHandler<ChannelT> {
-public:
-  ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
-
-  // Handle the result (no actual value, just a notification that the function
-  // has completed on the remote end) by calling the user-defined handler with
-  // Error::success().
-  Error handleResponse(ChannelT &C) override {
-    if (auto Err = C.endReceiveMessage())
-      return Err;
-    return Handler(Error::success());
-  }
-
-  // Abandon this response by calling the handler with an 'abandoned response'
-  // error.
-  void abandon() override {
-    if (auto Err = Handler(this->createAbandonedResponseError())) {
-      // Handlers should not fail when passed an abandoned response error.
-      report_fatal_error(std::move(Err));
-    }
-  }
-
-private:
-  HandlerT Handler;
-};
-
-template <typename ChannelT, typename FuncRetT, typename HandlerT>
-class ResponseHandlerImpl<ChannelT, Expected<FuncRetT>, HandlerT>
-    : public ResponseHandler<ChannelT> {
-public:
-  ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
-
-  // Handle the result by deserializing it from the channel then passing it
-  // to the user defined handler.
-  Error handleResponse(ChannelT &C) override {
-    using HandlerArgType = typename ResponseHandlerArg<
-        typename HandlerTraits<HandlerT>::Type>::ArgType;
-    HandlerArgType Result((typename HandlerArgType::value_type()));
-
-    if (auto Err =
-            SerializationTraits<ChannelT, Expected<FuncRetT>,
-                                HandlerArgType>::deserialize(C, Result))
-      return Err;
-    if (auto Err = C.endReceiveMessage())
-      return Err;
-    return Handler(std::move(Result));
-  }
-
-  // Abandon this response by calling the handler with an 'abandoned response'
-  // error.
-  void abandon() override {
-    if (auto Err = Handler(this->createAbandonedResponseError())) {
-      // Handlers should not fail when passed an abandoned response error.
-      report_fatal_error(std::move(Err));
-    }
-  }
-
-private:
-  HandlerT Handler;
-};
-
-template <typename ChannelT, typename HandlerT>
-class ResponseHandlerImpl<ChannelT, Error, HandlerT>
-    : public ResponseHandler<ChannelT> {
-public:
-  ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
-
-  // Handle the result by deserializing it from the channel then passing it
-  // to the user defined handler.
-  Error handleResponse(ChannelT &C) override {
-    Error Result = Error::success();
-    if (auto Err = SerializationTraits<ChannelT, Error, Error>::deserialize(
-            C, Result)) {
-      consumeError(std::move(Result));
-      return Err;
-    }
-    if (auto Err = C.endReceiveMessage()) {
-      consumeError(std::move(Result));
-      return Err;
-    }
-    return Handler(std::move(Result));
-  }
-
-  // Abandon this response by calling the handler with an 'abandoned response'
-  // error.
-  void abandon() override {
-    if (auto Err = Handler(this->createAbandonedResponseError())) {
-      // Handlers should not fail when passed an abandoned response error.
-      report_fatal_error(std::move(Err));
-    }
-  }
-
-private:
-  HandlerT Handler;
-};
-
-// Create a ResponseHandler from a given user handler.
-template <typename ChannelT, typename FuncRetT, typename HandlerT>
-std::unique_ptr<ResponseHandler<ChannelT>> createResponseHandler(HandlerT H) {
-  return std::make_unique<ResponseHandlerImpl<ChannelT, FuncRetT, HandlerT>>(
-      std::move(H));
-}
-
-// Helper for wrapping member functions up as functors. This is useful for
-// installing methods as result handlers.
-template <typename ClassT, typename RetT, typename... ArgTs>
-class MemberFnWrapper {
-public:
-  using MethodT = RetT (ClassT::*)(ArgTs...);
-  MemberFnWrapper(ClassT &Instance, MethodT Method)
-      : Instance(Instance), Method(Method) {}
-  RetT operator()(ArgTs &&... Args) {
-    return (Instance.*Method)(std::move(Args)...);
-  }
-
-private:
-  ClassT &Instance;
-  MethodT Method;
-};
-
-// Helper that provides a Functor for deserializing arguments.
-template <typename... ArgTs> class ReadArgs {
-public:
-  Error operator()() { return Error::success(); }
-};
-
-template <typename ArgT, typename... ArgTs>
-class ReadArgs<ArgT, ArgTs...> : public ReadArgs<ArgTs...> {
-public:
-  ReadArgs(ArgT &Arg, ArgTs &... Args)
-      : ReadArgs<ArgTs...>(Args...), Arg(Arg) {}
-
-  Error operator()(ArgT &ArgVal, ArgTs &... ArgVals) {
-    this->Arg = std::move(ArgVal);
-    return ReadArgs<ArgTs...>::operator()(ArgVals...);
-  }
-
-private:
-  ArgT &Arg;
-};
-
-// Manage sequence numbers.
-template <typename SequenceNumberT> class SequenceNumberManager {
-public:
-  // Reset, making all sequence numbers available.
-  void reset() {
-    std::lock_guard<std::mutex> Lock(SeqNoLock);
-    NextSequenceNumber = 0;
-    FreeSequenceNumbers.clear();
-  }
-
-  // Get the next available sequence number. Will re-use numbers that have
-  // been released.
-  SequenceNumberT getSequenceNumber() {
-    std::lock_guard<std::mutex> Lock(SeqNoLock);
-    if (FreeSequenceNumbers.empty())
-      return NextSequenceNumber++;
-    auto SequenceNumber = FreeSequenceNumbers.back();
-    FreeSequenceNumbers.pop_back();
-    return SequenceNumber;
-  }
-
-  // Release a sequence number, making it available for re-use.
-  void releaseSequenceNumber(SequenceNumberT SequenceNumber) {
-    std::lock_guard<std::mutex> Lock(SeqNoLock);
-    FreeSequenceNumbers.push_back(SequenceNumber);
-  }
-
-private:
-  std::mutex SeqNoLock;
-  SequenceNumberT NextSequenceNumber = 0;
-  std::vector<SequenceNumberT> FreeSequenceNumbers;
-};
-
-// Checks that predicate P holds for each corresponding pair of type arguments
-// from T1 and T2 tuple.
-template <template <class, class> class P, typename T1Tuple, typename T2Tuple>
-class RPCArgTypeCheckHelper;
-
-template <template <class, class> class P>
-class RPCArgTypeCheckHelper<P, std::tuple<>, std::tuple<>> {
-public:
-  static const bool value = true;
-};
-
-template <template <class, class> class P, typename T, typename... Ts,
-          typename U, typename... Us>
-class RPCArgTypeCheckHelper<P, std::tuple<T, Ts...>, std::tuple<U, Us...>> {
-public:
-  static const bool value =
-      P<T, U>::value &&
-      RPCArgTypeCheckHelper<P, std::tuple<Ts...>, std::tuple<Us...>>::value;
-};
-
-template <template <class, class> class P, typename T1Sig, typename T2Sig>
-class RPCArgTypeCheck {
-public:
-  using T1Tuple = typename FunctionArgsTuple<T1Sig>::Type;
-  using T2Tuple = typename FunctionArgsTuple<T2Sig>::Type;
-
-  static_assert(std::tuple_size<T1Tuple>::value >=
-                    std::tuple_size<T2Tuple>::value,
-                "Too many arguments to RPC call");
-  static_assert(std::tuple_size<T1Tuple>::value <=
-                    std::tuple_size<T2Tuple>::value,
-                "Too few arguments to RPC call");
-
-  static const bool value = RPCArgTypeCheckHelper<P, T1Tuple, T2Tuple>::value;
-};
-
-template <typename ChannelT, typename WireT, typename ConcreteT>
-class CanSerialize {
-private:
-  using S = SerializationTraits<ChannelT, WireT, ConcreteT>;
-
-  template <typename T>
-  static std::true_type
-  check(typename std::enable_if<
-        std::is_same<decltype(T::serialize(std::declval<ChannelT &>(),
-                                           std::declval<const ConcreteT &>())),
-                     Error>::value,
-        void *>::type);
-
-  template <typename> static std::false_type check(...);
-
-public:
-  static const bool value = decltype(check<S>(0))::value;
-};
-
-template <typename ChannelT, typename WireT, typename ConcreteT>
-class CanDeserialize {
-private:
-  using S = SerializationTraits<ChannelT, WireT, ConcreteT>;
-
-  template <typename T>
-  static std::true_type
-  check(typename std::enable_if<
-        std::is_same<decltype(T::deserialize(std::declval<ChannelT &>(),
-                                             std::declval<ConcreteT &>())),
-                     Error>::value,
-        void *>::type);
-
-  template <typename> static std::false_type check(...);
-
-public:
-  static const bool value = decltype(check<S>(0))::value;
-};
-
-/// Contains primitive utilities for defining, calling and handling calls to
-/// remote procedures. ChannelT is a bidirectional stream conforming to the
-/// RPCChannel interface (see RPCChannel.h), FunctionIdT is a procedure
-/// identifier type that must be serializable on ChannelT, and SequenceNumberT
-/// is an integral type that will be used to number in-flight function calls.
-///
-/// These utilities support the construction of very primitive RPC utilities.
-/// Their intent is to ensure correct serialization and deserialization of
-/// procedure arguments, and to keep the client and server's view of the API in
-/// sync.
-template <typename ImplT, typename ChannelT, typename FunctionIdT,
-          typename SequenceNumberT>
-class RPCEndpointBase {
-protected:
-  class OrcRPCInvalid : public Function<OrcRPCInvalid, void()> {
-  public:
-    static const char *getName() { return "__orc_rpc$invalid"; }
-  };
-
-  class OrcRPCResponse : public Function<OrcRPCResponse, void()> {
-  public:
-    static const char *getName() { return "__orc_rpc$response"; }
-  };
-
-  class OrcRPCNegotiate
-      : public Function<OrcRPCNegotiate, FunctionIdT(std::string)> {
-  public:
-    static const char *getName() { return "__orc_rpc$negotiate"; }
-  };
-
-  // Helper predicate for testing for the presence of SerializeTraits
-  // serializers.
-  template <typename WireT, typename ConcreteT>
-  class CanSerializeCheck : detail::CanSerialize<ChannelT, WireT, ConcreteT> {
-  public:
-    using detail::CanSerialize<ChannelT, WireT, ConcreteT>::value;
-
-    static_assert(value, "Missing serializer for argument (Can't serialize the "
-                         "first template type argument of CanSerializeCheck "
-                         "from the second)");
-  };
-
-  // Helper predicate for testing for the presence of SerializeTraits
-  // deserializers.
-  template <typename WireT, typename ConcreteT>
-  class CanDeserializeCheck
-      : detail::CanDeserialize<ChannelT, WireT, ConcreteT> {
-  public:
-    using detail::CanDeserialize<ChannelT, WireT, ConcreteT>::value;
-
-    static_assert(value, "Missing deserializer for argument (Can't deserialize "
-                         "the second template type argument of "
-                         "CanDeserializeCheck from the first)");
-  };
-
-public:
-  /// Construct an RPC instance on a channel.
-  RPCEndpointBase(ChannelT &C, bool LazyAutoNegotiation)
-      : C(C), LazyAutoNegotiation(LazyAutoNegotiation) {
-    // Hold ResponseId in a special variable, since we expect Response to be
-    // called relatively frequently, and want to avoid the map lookup.
-    ResponseId = FnIdAllocator.getResponseId();
-    RemoteFunctionIds[OrcRPCResponse::getPrototype()] = ResponseId;
-
-    // Register the negotiate function id and handler.
-    auto NegotiateId = FnIdAllocator.getNegotiateId();
-    RemoteFunctionIds[OrcRPCNegotiate::getPrototype()] = NegotiateId;
-    Handlers[NegotiateId] = wrapHandler<OrcRPCNegotiate>(
-        [this](const std::string &Name) { return handleNegotiate(Name); });
-  }
-
-
-  /// Negotiate a function id for Func with the other end of the channel.
-  template <typename Func> Error negotiateFunction(bool Retry = false) {
-    return getRemoteFunctionId<Func>(true, Retry).takeError();
-  }
-
-  /// Append a call Func, does not call send on the channel.
-  /// The first argument specifies a user-defined handler to be run when the
-  /// function returns. The handler should take an Expected<Func::ReturnType>,
-  /// or an Error (if Func::ReturnType is void). The handler will be called
-  /// with an error if the return value is abandoned due to a channel error.
-  template <typename Func, typename HandlerT, typename... ArgTs>
-  Error appendCallAsync(HandlerT Handler, const ArgTs &... Args) {
-
-    static_assert(
-        detail::RPCArgTypeCheck<CanSerializeCheck, typename Func::Type,
-                                void(ArgTs...)>::value,
-        "");
-
-    // Look up the function ID.
-    FunctionIdT FnId;
-    if (auto FnIdOrErr = getRemoteFunctionId<Func>(LazyAutoNegotiation, false))
-      FnId = *FnIdOrErr;
-    else {
-      // Negotiation failed. Notify the handler then return the negotiate-failed
-      // error.
-      cantFail(Handler(make_error<ResponseAbandoned>()));
-      return FnIdOrErr.takeError();
-    }
-
-    SequenceNumberT SeqNo; // initialized in locked scope below.
-    {
-      // Lock the pending responses map and sequence number manager.
-      std::lock_guard<std::mutex> Lock(ResponsesMutex);
-
-      // Allocate a sequence number.
-      SeqNo = SequenceNumberMgr.getSequenceNumber();
-      assert(!PendingResponses.count(SeqNo) &&
-             "Sequence number already allocated");
-
-      // Install the user handler.
-      PendingResponses[SeqNo] =
-        detail::createResponseHandler<ChannelT, typename Func::ReturnType>(
-            std::move(Handler));
-    }
-
-    // Open the function call message.
-    if (auto Err = C.startSendMessage(FnId, SeqNo)) {
-      abandonPendingResponses();
-      return Err;
-    }
-
-    // Serialize the call arguments.
-    if (auto Err = detail::HandlerTraits<typename Func::Type>::serializeArgs(
-            C, Args...)) {
-      abandonPendingResponses();
-      return Err;
-    }
-
-    // Close the function call messagee.
-    if (auto Err = C.endSendMessage()) {
-      abandonPendingResponses();
-      return Err;
-    }
-
-    return Error::success();
-  }
-
-  Error sendAppendedCalls() { return C.send(); };
-
-  template <typename Func, typename HandlerT, typename... ArgTs>
-  Error callAsync(HandlerT Handler, const ArgTs &... Args) {
-    if (auto Err = appendCallAsync<Func>(std::move(Handler), Args...))
-      return Err;
-    return C.send();
-  }
-
-  /// Handle one incoming call.
-  Error handleOne() {
-    FunctionIdT FnId;
-    SequenceNumberT SeqNo;
-    if (auto Err = C.startReceiveMessage(FnId, SeqNo)) {
-      abandonPendingResponses();
-      return Err;
-    }
-    if (FnId == ResponseId)
-      return handleResponse(SeqNo);
-    auto I = Handlers.find(FnId);
-    if (I != Handlers.end())
-      return I->second(C, SeqNo);
-
-    // else: No handler found. Report error to client?
-    return make_error<BadFunctionCall<FunctionIdT, SequenceNumberT>>(FnId,
-                                                                     SeqNo);
-  }
-
-  /// Helper for handling setter procedures - this method returns a functor that
-  /// sets the variables referred to by Args... to values deserialized from the
-  /// channel.
-  /// E.g.
-  ///
-  ///   typedef Function<0, bool, int> Func1;
-  ///
-  ///   ...
-  ///   bool B;
-  ///   int I;
-  ///   if (auto Err = expect<Func1>(Channel, readArgs(B, I)))
-  ///     /* Handle Args */ ;
-  ///
-  template <typename... ArgTs>
-  static detail::ReadArgs<ArgTs...> readArgs(ArgTs &... Args) {
-    return detail::ReadArgs<ArgTs...>(Args...);
-  }
-
-  /// Abandon all outstanding result handlers.
-  ///
-  /// This will call all currently registered result handlers to receive an
-  /// "abandoned" error as their argument. This is used internally by the RPC
-  /// in error situations, but can also be called directly by clients who are
-  /// disconnecting from the remote and don't or can't expect responses to their
-  /// outstanding calls. (Especially for outstanding blocking calls, calling
-  /// this function may be necessary to avoid dead threads).
-  void abandonPendingResponses() {
-    // Lock the pending responses map and sequence number manager.
-    std::lock_guard<std::mutex> Lock(ResponsesMutex);
-
-    for (auto &KV : PendingResponses)
-      KV.second->abandon();
-    PendingResponses.clear();
-    SequenceNumberMgr.reset();
-  }
-
-  /// Remove the handler for the given function.
-  /// A handler must currently be registered for this function.
-  template <typename Func>
-  void removeHandler() {
-    auto IdItr = LocalFunctionIds.find(Func::getPrototype());
-    assert(IdItr != LocalFunctionIds.end() &&
-           "Function does not have a registered handler");
-    auto HandlerItr = Handlers.find(IdItr->second);
-    assert(HandlerItr != Handlers.end() &&
-           "Function does not have a registered handler");
-    Handlers.erase(HandlerItr);
-  }
-
-  /// Clear all handlers.
-  void clearHandlers() {
-    Handlers.clear();
-  }
-
-protected:
-
-  FunctionIdT getInvalidFunctionId() const {
-    return FnIdAllocator.getInvalidId();
-  }
-
-  /// Add the given handler to the handler map and make it available for
-  /// autonegotiation and execution.
-  template <typename Func, typename HandlerT>
-  void addHandlerImpl(HandlerT Handler) {
-
-    static_assert(detail::RPCArgTypeCheck<
-                      CanDeserializeCheck, typename Func::Type,
-                      typename detail::HandlerTraits<HandlerT>::Type>::value,
-                  "");
-
-    FunctionIdT NewFnId = FnIdAllocator.template allocate<Func>();
-    LocalFunctionIds[Func::getPrototype()] = NewFnId;
-    Handlers[NewFnId] = wrapHandler<Func>(std::move(Handler));
-  }
-
-  template <typename Func, typename HandlerT>
-  void addAsyncHandlerImpl(HandlerT Handler) {
-
-    static_assert(detail::RPCArgTypeCheck<
-                      CanDeserializeCheck, typename Func::Type,
-                      typename detail::AsyncHandlerTraits<
-                        typename detail::HandlerTraits<HandlerT>::Type
-                      >::Type>::value,
-                  "");
-
-    FunctionIdT NewFnId = FnIdAllocator.template allocate<Func>();
-    LocalFunctionIds[Func::getPrototype()] = NewFnId;
-    Handlers[NewFnId] = wrapAsyncHandler<Func>(std::move(Handler));
-  }
-
-  Error handleResponse(SequenceNumberT SeqNo) {
-    using Handler = typename decltype(PendingResponses)::mapped_type;
-    Handler PRHandler;
-
-    {
-      // Lock the pending responses map and sequence number manager.
-      std::unique_lock<std::mutex> Lock(ResponsesMutex);
-      auto I = PendingResponses.find(SeqNo);
-
-      if (I != PendingResponses.end()) {
-        PRHandler = std::move(I->second);
-        PendingResponses.erase(I);
-        SequenceNumberMgr.releaseSequenceNumber(SeqNo);
-      } else {
-        // Unlock the pending results map to prevent recursive lock.
-        Lock.unlock();
-        abandonPendingResponses();
-        return make_error<
-                 InvalidSequenceNumberForResponse<SequenceNumberT>>(SeqNo);
-      }
-    }
-
-    assert(PRHandler &&
-           "If we didn't find a response handler we should have bailed out");
-
-    if (auto Err = PRHandler->handleResponse(C)) {
-      abandonPendingResponses();
-      return Err;
-    }
-
-    return Error::success();
-  }
-
-  FunctionIdT handleNegotiate(const std::string &Name) {
-    auto I = LocalFunctionIds.find(Name);
-    if (I == LocalFunctionIds.end())
-      return getInvalidFunctionId();
-    return I->second;
-  }
-
-  // Find the remote FunctionId for the given function.
-  template <typename Func>
-  Expected<FunctionIdT> getRemoteFunctionId(bool NegotiateIfNotInMap,
-                                            bool NegotiateIfInvalid) {
-    bool DoNegotiate;
-
-    // Check if we already have a function id...
-    auto I = RemoteFunctionIds.find(Func::getPrototype());
-    if (I != RemoteFunctionIds.end()) {
-      // If it's valid there's nothing left to do.
-      if (I->second != getInvalidFunctionId())
-        return I->second;
-      DoNegotiate = NegotiateIfInvalid;
-    } else
-      DoNegotiate = NegotiateIfNotInMap;
-
-    // We don't have a function id for Func yet, but we're allowed to try to
-    // negotiate one.
-    if (DoNegotiate) {
-      auto &Impl = static_cast<ImplT &>(*this);
-      if (auto RemoteIdOrErr =
-          Impl.template callB<OrcRPCNegotiate>(Func::getPrototype())) {
-        RemoteFunctionIds[Func::getPrototype()] = *RemoteIdOrErr;
-        if (*RemoteIdOrErr == getInvalidFunctionId())
-          return make_error<CouldNotNegotiate>(Func::getPrototype());
-        return *RemoteIdOrErr;
-      } else
-        return RemoteIdOrErr.takeError();
-    }
-
-    // No key was available in the map and we weren't allowed to try to
-    // negotiate one, so return an unknown function error.
-    return make_error<CouldNotNegotiate>(Func::getPrototype());
-  }
-
-  using WrappedHandlerFn = std::function<Error(ChannelT &, SequenceNumberT)>;
-
-  // Wrap the given user handler in the necessary argument-deserialization code,
-  // result-serialization code, and call to the launch policy (if present).
-  template <typename Func, typename HandlerT>
-  WrappedHandlerFn wrapHandler(HandlerT Handler) {
-    return [this, Handler](ChannelT &Channel,
-                           SequenceNumberT SeqNo) mutable -> Error {
-      // Start by deserializing the arguments.
-      using ArgsTuple =
-          typename detail::FunctionArgsTuple<
-            typename detail::HandlerTraits<HandlerT>::Type>::Type;
-      auto Args = std::make_shared<ArgsTuple>();
-
-      if (auto Err =
-              detail::HandlerTraits<typename Func::Type>::deserializeArgs(
-                  Channel, *Args))
-        return Err;
-
-      // GCC 4.7 and 4.8 incorrectly issue a -Wunused-but-set-variable warning
-      // for RPCArgs. Void cast RPCArgs to work around this for now.
-      // FIXME: Remove this workaround once we can assume a working GCC version.
-      (void)Args;
-
-      // End receieve message, unlocking the channel for reading.
-      if (auto Err = Channel.endReceiveMessage())
-        return Err;
-
-      using HTraits = detail::HandlerTraits<HandlerT>;
-      using FuncReturn = typename Func::ReturnType;
-      return detail::respond<FuncReturn>(Channel, ResponseId, SeqNo,
-                                         HTraits::unpackAndRun(Handler, *Args));
-    };
-  }
-
-  // Wrap the given user handler in the necessary argument-deserialization code,
-  // result-serialization code, and call to the launch policy (if present).
-  template <typename Func, typename HandlerT>
-  WrappedHandlerFn wrapAsyncHandler(HandlerT Handler) {
-    return [this, Handler](ChannelT &Channel,
-                           SequenceNumberT SeqNo) mutable -> Error {
-      // Start by deserializing the arguments.
-      using AHTraits = detail::AsyncHandlerTraits<
-                         typename detail::HandlerTraits<HandlerT>::Type>;
-      using ArgsTuple =
-          typename detail::FunctionArgsTuple<typename AHTraits::Type>::Type;
-      auto Args = std::make_shared<ArgsTuple>();
-
-      if (auto Err =
-              detail::HandlerTraits<typename Func::Type>::deserializeArgs(
-                  Channel, *Args))
-        return Err;
-
-      // GCC 4.7 and 4.8 incorrectly issue a -Wunused-but-set-variable warning
-      // for RPCArgs. Void cast RPCArgs to work around this for now.
-      // FIXME: Remove this workaround once we can assume a working GCC version.
-      (void)Args;
-
-      // End receieve message, unlocking the channel for reading.
-      if (auto Err = Channel.endReceiveMessage())
-        return Err;
-
-      using HTraits = detail::HandlerTraits<HandlerT>;
-      using FuncReturn = typename Func::ReturnType;
-      auto Responder =
-        [this, SeqNo](typename AHTraits::ResultType RetVal) -> Error {
-          return detail::respond<FuncReturn>(C, ResponseId, SeqNo,
-                                             std::move(RetVal));
-        };
-
-      return HTraits::unpackAndRunAsync(Handler, Responder, *Args);
-    };
-  }
-
-  ChannelT &C;
-
-  bool LazyAutoNegotiation;
-
-  RPCFunctionIdAllocator<FunctionIdT> FnIdAllocator;
-
-  FunctionIdT ResponseId;
-  std::map<std::string, FunctionIdT> LocalFunctionIds;
-  std::map<const char *, FunctionIdT> RemoteFunctionIds;
-
-  std::map<FunctionIdT, WrappedHandlerFn> Handlers;
-
-  std::mutex ResponsesMutex;
-  detail::SequenceNumberManager<SequenceNumberT> SequenceNumberMgr;
-  std::map<SequenceNumberT, std::unique_ptr<detail::ResponseHandler<ChannelT>>>
-      PendingResponses;
-};
-
-} // end namespace detail
-
-template <typename ChannelT, typename FunctionIdT = uint32_t,
-          typename SequenceNumberT = uint32_t>
-class MultiThreadedRPCEndpoint
-    : public detail::RPCEndpointBase<
-          MultiThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
-          ChannelT, FunctionIdT, SequenceNumberT> {
-private:
-  using BaseClass =
-      detail::RPCEndpointBase<
-        MultiThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
-        ChannelT, FunctionIdT, SequenceNumberT>;
-
-public:
-  MultiThreadedRPCEndpoint(ChannelT &C, bool LazyAutoNegotiation)
-      : BaseClass(C, LazyAutoNegotiation) {}
-
-  /// Add a handler for the given RPC function.
-  /// This installs the given handler functor for the given RPC Function, and
-  /// makes the RPC function available for negotiation/calling from the remote.
-  template <typename Func, typename HandlerT>
-  void addHandler(HandlerT Handler) {
-    return this->template addHandlerImpl<Func>(std::move(Handler));
-  }
-
-  /// Add a class-method as a handler.
-  template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
-  void addHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
-    addHandler<Func>(
-      detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
-  }
-
-  template <typename Func, typename HandlerT>
-  void addAsyncHandler(HandlerT Handler) {
-    return this->template addAsyncHandlerImpl<Func>(std::move(Handler));
-  }
-
-  /// Add a class-method as a handler.
-  template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
-  void addAsyncHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
-    addAsyncHandler<Func>(
-      detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
-  }
-
-  /// Return type for non-blocking call primitives.
-  template <typename Func>
-  using NonBlockingCallResult = typename detail::ResultTraits<
-      typename Func::ReturnType>::ReturnFutureType;
-
-  /// Call Func on Channel C. Does not block, does not call send. Returns a pair
-  /// of a future result and the sequence number assigned to the result.
-  ///
-  /// This utility function is primarily used for single-threaded mode support,
-  /// where the sequence number can be used to wait for the corresponding
-  /// result. In multi-threaded mode the appendCallNB method, which does not
-  /// return the sequence numeber, should be preferred.
-  template <typename Func, typename... ArgTs>
-  Expected<NonBlockingCallResult<Func>> appendCallNB(const ArgTs &... Args) {
-    using RTraits = detail::ResultTraits<typename Func::ReturnType>;
-    using ErrorReturn = typename RTraits::ErrorReturnType;
-    using ErrorReturnPromise = typename RTraits::ReturnPromiseType;
-
-    ErrorReturnPromise Promise;
-    auto FutureResult = Promise.get_future();
-
-    if (auto Err = this->template appendCallAsync<Func>(
-            [Promise = std::move(Promise)](ErrorReturn RetOrErr) mutable {
-              Promise.set_value(std::move(RetOrErr));
-              return Error::success();
-            },
-            Args...)) {
-      RTraits::consumeAbandoned(FutureResult.get());
-      return std::move(Err);
-    }
-    return std::move(FutureResult);
-  }
-
-  /// The same as appendCallNBWithSeq, except that it calls C.send() to
-  /// flush the channel after serializing the call.
-  template <typename Func, typename... ArgTs>
-  Expected<NonBlockingCallResult<Func>> callNB(const ArgTs &... Args) {
-    auto Result = appendCallNB<Func>(Args...);
-    if (!Result)
-      return Result;
-    if (auto Err = this->C.send()) {
-      this->abandonPendingResponses();
-      detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
-          std::move(Result->get()));
-      return std::move(Err);
-    }
-    return Result;
-  }
-
-  /// Call Func on Channel C. Blocks waiting for a result. Returns an Error
-  /// for void functions or an Expected<T> for functions returning a T.
-  ///
-  /// This function is for use in threaded code where another thread is
-  /// handling responses and incoming calls.
-  template <typename Func, typename... ArgTs,
-            typename AltRetT = typename Func::ReturnType>
-  typename detail::ResultTraits<AltRetT>::ErrorReturnType
-  callB(const ArgTs &... Args) {
-    if (auto FutureResOrErr = callNB<Func>(Args...))
-      return FutureResOrErr->get();
-    else
-      return FutureResOrErr.takeError();
-  }
-
-  /// Handle incoming RPC calls.
-  Error handlerLoop() {
-    while (true)
-      if (auto Err = this->handleOne())
-        return Err;
-    return Error::success();
-  }
-};
-
-template <typename ChannelT, typename FunctionIdT = uint32_t,
-          typename SequenceNumberT = uint32_t>
-class SingleThreadedRPCEndpoint
-    : public detail::RPCEndpointBase<
-          SingleThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
-          ChannelT, FunctionIdT, SequenceNumberT> {
-private:
-  using BaseClass =
-      detail::RPCEndpointBase<
-        SingleThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
-        ChannelT, FunctionIdT, SequenceNumberT>;
-
-public:
-  SingleThreadedRPCEndpoint(ChannelT &C, bool LazyAutoNegotiation)
-      : BaseClass(C, LazyAutoNegotiation) {}
-
-  template <typename Func, typename HandlerT>
-  void addHandler(HandlerT Handler) {
-    return this->template addHandlerImpl<Func>(std::move(Handler));
-  }
-
-  template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
-  void addHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
-    addHandler<Func>(
-        detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
-  }
-
-  template <typename Func, typename HandlerT>
-  void addAsyncHandler(HandlerT Handler) {
-    return this->template addAsyncHandlerImpl<Func>(std::move(Handler));
-  }
-
-  /// Add a class-method as a handler.
-  template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
-  void addAsyncHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
-    addAsyncHandler<Func>(
-      detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
-  }
-
-  template <typename Func, typename... ArgTs,
-            typename AltRetT = typename Func::ReturnType>
-  typename detail::ResultTraits<AltRetT>::ErrorReturnType
-  callB(const ArgTs &... Args) {
-    bool ReceivedResponse = false;
-    using ResultType = typename detail::ResultTraits<AltRetT>::ErrorReturnType;
-    auto Result = detail::ResultTraits<AltRetT>::createBlankErrorReturnValue();
-
-    // We have to 'Check' result (which we know is in a success state at this
-    // point) so that it can be overwritten in the async handler.
-    (void)!!Result;
-
-    if (auto Err = this->template appendCallAsync<Func>(
-            [&](ResultType R) {
-              Result = std::move(R);
-              ReceivedResponse = true;
-              return Error::success();
-            },
-            Args...)) {
-      detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
-          std::move(Result));
-      return std::move(Err);
-    }
-
-    if (auto Err = this->C.send()) {
-      detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
-          std::move(Result));
-      return std::move(Err);
-    }
-
-    while (!ReceivedResponse) {
-      if (auto Err = this->handleOne()) {
-        detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
-            std::move(Result));
-        return std::move(Err);
-      }
-    }
-
-    return Result;
-  }
-};
-
-/// Asynchronous dispatch for a function on an RPC endpoint.
-template <typename RPCClass, typename Func>
-class RPCAsyncDispatch {
-public:
-  RPCAsyncDispatch(RPCClass &Endpoint) : Endpoint(Endpoint) {}
-
-  template <typename HandlerT, typename... ArgTs>
-  Error operator()(HandlerT Handler, const ArgTs &... Args) const {
-    return Endpoint.template appendCallAsync<Func>(std::move(Handler), Args...);
-  }
-
-private:
-  RPCClass &Endpoint;
-};
-
-/// Construct an asynchronous dispatcher from an RPC endpoint and a Func.
-template <typename Func, typename RPCEndpointT>
-RPCAsyncDispatch<RPCEndpointT, Func> rpcAsyncDispatch(RPCEndpointT &Endpoint) {
-  return RPCAsyncDispatch<RPCEndpointT, Func>(Endpoint);
-}
-
-/// Allows a set of asynchrounous calls to be dispatched, and then
-///        waited on as a group.
-class ParallelCallGroup {
-public:
-
-  ParallelCallGroup() = default;
-  ParallelCallGroup(const ParallelCallGroup &) = delete;
-  ParallelCallGroup &operator=(const ParallelCallGroup &) = delete;
-
-  /// Make as asynchronous call.
-  template <typename AsyncDispatcher, typename HandlerT, typename... ArgTs>
-  Error call(const AsyncDispatcher &AsyncDispatch, HandlerT Handler,
-             const ArgTs &... Args) {
-    // Increment the count of outstanding calls. This has to happen before
-    // we invoke the call, as the handler may (depending on scheduling)
-    // be run immediately on another thread, and we don't want the decrement
-    // in the wrapped handler below to run before the increment.
-    {
-      std::unique_lock<std::mutex> Lock(M);
-      ++NumOutstandingCalls;
-    }
-
-    // Wrap the user handler in a lambda that will decrement the
-    // outstanding calls count, then poke the condition variable.
-    using ArgType = typename detail::ResponseHandlerArg<
-        typename detail::HandlerTraits<HandlerT>::Type>::ArgType;
-    auto WrappedHandler = [this, Handler = std::move(Handler)](ArgType Arg) {
-      auto Err = Handler(std::move(Arg));
-      std::unique_lock<std::mutex> Lock(M);
-      --NumOutstandingCalls;
-      CV.notify_all();
-      return Err;
-    };
-
-    return AsyncDispatch(std::move(WrappedHandler), Args...);
-  }
-
-  /// Blocks until all calls have been completed and their return value
-  ///        handlers run.
-  void wait() {
-    std::unique_lock<std::mutex> Lock(M);
-    while (NumOutstandingCalls > 0)
-      CV.wait(Lock);
-  }
-
-private:
-  std::mutex M;
-  std::condition_variable CV;
-  uint32_t NumOutstandingCalls = 0;
-};
-
-/// Convenience class for grouping RPC Functions into APIs that can be
-///        negotiated as a block.
-///
-template <typename... Funcs>
-class APICalls {
-public:
-
-  /// Test whether this API contains Function F.
-  template <typename F>
-  class Contains {
-  public:
-    static const bool value = false;
-  };
-
-  /// Negotiate all functions in this API.
-  template <typename RPCEndpoint>
-  static Error negotiate(RPCEndpoint &R) {
-    return Error::success();
-  }
-};
-
-template <typename Func, typename... Funcs>
-class APICalls<Func, Funcs...> {
-public:
-
-  template <typename F>
-  class Contains {
-  public:
-    static const bool value = std::is_same<F, Func>::value |
-                              APICalls<Funcs...>::template Contains<F>::value;
-  };
-
-  template <typename RPCEndpoint>
-  static Error negotiate(RPCEndpoint &R) {
-    if (auto Err = R.template negotiateFunction<Func>())
-      return Err;
-    return APICalls<Funcs...>::negotiate(R);
-  }
-
-};
-
-template <typename... InnerFuncs, typename... Funcs>
-class APICalls<APICalls<InnerFuncs...>, Funcs...> {
-public:
-
-  template <typename F>
-  class Contains {
-  public:
-    static const bool value =
-      APICalls<InnerFuncs...>::template Contains<F>::value |
-      APICalls<Funcs...>::template Contains<F>::value;
-  };
-
-  template <typename RPCEndpoint>
-  static Error negotiate(RPCEndpoint &R) {
-    if (auto Err = APICalls<InnerFuncs...>::negotiate(R))
-      return Err;
-    return APICalls<Funcs...>::negotiate(R);
-  }
-
-};
-
-} // end namespace rpc
-} // end namespace orc
-} // end namespace llvm
-
-#endif
diff --git a/llvm/include/llvm/ExecutionEngine/Orc/RawByteChannel.h b/llvm/include/llvm/ExecutionEngine/Orc/RawByteChannel.h
deleted file mode 100644
index 46b7c59450e..00000000000
--- a/llvm/include/llvm/ExecutionEngine/Orc/RawByteChannel.h
+++ /dev/null
@@ -1,184 +0,0 @@
-//===- llvm/ExecutionEngine/Orc/RawByteChannel.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 LLVM_EXECUTIONENGINE_ORC_RAWBYTECHANNEL_H
-#define LLVM_EXECUTIONENGINE_ORC_RAWBYTECHANNEL_H
-
-#include "llvm/ADT/StringRef.h"
-#include "llvm/ExecutionEngine/Orc/RPCSerialization.h"
-#include "llvm/Support/Endian.h"
-#include "llvm/Support/Error.h"
-#include <cstdint>
-#include <mutex>
-#include <string>
-#include <type_traits>
-
-namespace llvm {
-namespace orc {
-namespace rpc {
-
-/// Interface for byte-streams to be used with RPC.
-class RawByteChannel {
-public:
-  virtual ~RawByteChannel() = default;
-
-  /// Read Size bytes from the stream into *Dst.
-  virtual Error readBytes(char *Dst, unsigned Size) = 0;
-
-  /// Read size bytes from *Src and append them to the stream.
-  virtual Error appendBytes(const char *Src, unsigned Size) = 0;
-
-  /// Flush the stream if possible.
-  virtual Error send() = 0;
-
-  /// Notify the channel that we're starting a message send.
-  /// Locks the channel for writing.
-  template <typename FunctionIdT, typename SequenceIdT>
-  Error startSendMessage(const FunctionIdT &FnId, const SequenceIdT &SeqNo) {
-    writeLock.lock();
-    if (auto Err = serializeSeq(*this, FnId, SeqNo)) {
-      writeLock.unlock();
-      return Err;
-    }
-    return Error::success();
-  }
-
-  /// Notify the channel that we're ending a message send.
-  /// Unlocks the channel for writing.
-  Error endSendMessage() {
-    writeLock.unlock();
-    return Error::success();
-  }
-
-  /// Notify the channel that we're starting a message receive.
-  /// Locks the channel for reading.
-  template <typename FunctionIdT, typename SequenceNumberT>
-  Error startReceiveMessage(FunctionIdT &FnId, SequenceNumberT &SeqNo) {
-    readLock.lock();
-    if (auto Err = deserializeSeq(*this, FnId, SeqNo)) {
-      readLock.unlock();
-      return Err;
-    }
-    return Error::success();
-  }
-
-  /// Notify the channel that we're ending a message receive.
-  /// Unlocks the channel for reading.
-  Error endReceiveMessage() {
-    readLock.unlock();
-    return Error::success();
-  }
-
-  /// Get the lock for stream reading.
-  std::mutex &getReadLock() { return readLock; }
-
-  /// Get the lock for stream writing.
-  std::mutex &getWriteLock() { return writeLock; }
-
-private:
-  std::mutex readLock, writeLock;
-};
-
-template <typename ChannelT, typename T>
-class SerializationTraits<
-    ChannelT, T, T,
-    typename std::enable_if<
-        std::is_base_of<RawByteChannel, ChannelT>::value &&
-        (std::is_same<T, uint8_t>::value || std::is_same<T, int8_t>::value ||
-         std::is_same<T, uint16_t>::value || std::is_same<T, int16_t>::value ||
-         std::is_same<T, uint32_t>::value || std::is_same<T, int32_t>::value ||
-         std::is_same<T, uint64_t>::value || std::is_same<T, int64_t>::value ||
-         std::is_same<T, char>::value)>::type> {
-public:
-  static Error serialize(ChannelT &C, T V) {
-    support::endian::byte_swap<T, support::big>(V);
-    return C.appendBytes(reinterpret_cast<const char *>(&V), sizeof(T));
-  };
-
-  static Error deserialize(ChannelT &C, T &V) {
-    if (auto Err = C.readBytes(reinterpret_cast<char *>(&V), sizeof(T)))
-      return Err;
-    support::endian::byte_swap<T, support::big>(V);
-    return Error::success();
-  };
-};
-
-template <typename ChannelT>
-class SerializationTraits<ChannelT, bool, bool,
-                          typename std::enable_if<std::is_base_of<
-                              RawByteChannel, ChannelT>::value>::type> {
-public:
-  static Error serialize(ChannelT &C, bool V) {
-    uint8_t Tmp = V ? 1 : 0;
-    if (auto Err =
-          C.appendBytes(reinterpret_cast<const char *>(&Tmp), 1))
-      return Err;
-    return Error::success();
-  }
-
-  static Error deserialize(ChannelT &C, bool &V) {
-    uint8_t Tmp = 0;
-    if (auto Err = C.readBytes(reinterpret_cast<char *>(&Tmp), 1))
-      return Err;
-    V = Tmp != 0;
-    return Error::success();
-  }
-};
-
-template <typename ChannelT>
-class SerializationTraits<ChannelT, std::string, StringRef,
-                          typename std::enable_if<std::is_base_of<
-                              RawByteChannel, ChannelT>::value>::type> {
-public:
-  /// RPC channel serialization for std::strings.
-  static Error serialize(RawByteChannel &C, StringRef S) {
-    if (auto Err = serializeSeq(C, static_cast<uint64_t>(S.size())))
-      return Err;
-    return C.appendBytes((const char *)S.data(), S.size());
-  }
-};
-
-template <typename ChannelT, typename T>
-class SerializationTraits<ChannelT, std::string, T,
-                          typename std::enable_if<
-                            std::is_base_of<RawByteChannel, ChannelT>::value &&
-                            (std::is_same<T, const char*>::value ||
-                             std::is_same<T, char*>::value)>::type> {
-public:
-  static Error serialize(RawByteChannel &C, const char *S) {
-    return SerializationTraits<ChannelT, std::string, StringRef>::serialize(C,
-                                                                            S);
-  }
-};
-
-template <typename ChannelT>
-class SerializationTraits<ChannelT, std::string, std::string,
-                          typename std::enable_if<std::is_base_of<
-                              RawByteChannel, ChannelT>::value>::type> {
-public:
-  /// RPC channel serialization for std::strings.
-  static Error serialize(RawByteChannel &C, const std::string &S) {
-    return SerializationTraits<ChannelT, std::string, StringRef>::serialize(C,
-                                                                            S);
-  }
-
-  /// RPC channel deserialization for std::strings.
-  static Error deserialize(RawByteChannel &C, std::string &S) {
-    uint64_t Count = 0;
-    if (auto Err = deserializeSeq(C, Count))
-      return Err;
-    S.resize(Count);
-    return C.readBytes(&S[0], Count);
-  }
-};
-
-} // end namespace rpc
-} // end namespace orc
-} // end namespace llvm
-
-#endif // LLVM_EXECUTIONENGINE_ORC_RAWBYTECHANNEL_H
diff --git a/llvm/lib/ExecutionEngine/CMakeLists.txt b/llvm/lib/ExecutionEngine/CMakeLists.txt
index ccee3460339..c5445fbc16d 100644
--- a/llvm/lib/ExecutionEngine/CMakeLists.txt
+++ b/llvm/lib/ExecutionEngine/CMakeLists.txt
@@ -21,6 +21,7 @@ endif()
 add_subdirectory(Interpreter)
 add_subdirectory(JITLink)
 add_subdirectory(MCJIT)
+add_subdirectory(OrcError)
 add_subdirectory(Orc)
 add_subdirectory(RuntimeDyld)
 
diff --git a/llvm/lib/ExecutionEngine/LLVMBuild.txt b/llvm/lib/ExecutionEngine/LLVMBuild.txt
index 13872da4a56..9bc6775f78a 100644
--- a/llvm/lib/ExecutionEngine/LLVMBuild.txt
+++ b/llvm/lib/ExecutionEngine/LLVMBuild.txt
@@ -16,7 +16,7 @@
 
 [common]
 subdirectories = Interpreter MCJIT JITLink RuntimeDyld IntelJITEvents
-                 OProfileJIT Orc PerfJITEvents
+                 OProfileJIT Orc OrcError PerfJITEvents
 
 [component_0]
 type = Library
diff --git a/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt b/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt
index 6c0881d4b25..e615fd8f234 100644
--- a/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt
+++ b/llvm/lib/ExecutionEngine/Orc/CMakeLists.txt
@@ -16,9 +16,7 @@ add_llvm_library(LLVMOrcJIT
   ObjectTransformLayer.cpp
   OrcABISupport.cpp
   OrcCBindings.cpp
-  OrcError.cpp
   OrcMCJITReplacement.cpp
-  RPCUtils.cpp
   RTDyldObjectLinkingLayer.cpp
   ThreadSafeModule.cpp
   Speculation.cpp
diff --git a/llvm/lib/ExecutionEngine/Orc/LLVMBuild.txt b/llvm/lib/ExecutionEngine/Orc/LLVMBuild.txt
index 11a7c5bf09b..4a78243551c 100644
--- a/llvm/lib/ExecutionEngine/Orc/LLVMBuild.txt
+++ b/llvm/lib/ExecutionEngine/Orc/LLVMBuild.txt
@@ -18,5 +18,5 @@
 type = Library
 name = OrcJIT
 parent = ExecutionEngine
-required_libraries = Core ExecutionEngine JITLink Object MC Passes RuntimeDyld
-                     Support Target TransformUtils
+required_libraries = Core ExecutionEngine JITLink Object OrcError MC Passes
+                     RuntimeDyld Support Target TransformUtils
diff --git a/llvm/lib/ExecutionEngine/Orc/OrcError.cpp b/llvm/lib/ExecutionEngine/Orc/OrcError.cpp
deleted file mode 100644
index e6e9a095319..00000000000
--- a/llvm/lib/ExecutionEngine/Orc/OrcError.cpp
+++ /dev/null
@@ -1,115 +0,0 @@
-//===---------------- OrcError.cpp - Error codes for ORC ------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-//
-// Error codes for ORC.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ExecutionEngine/Orc/OrcError.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/ManagedStatic.h"
-
-using namespace llvm;
-using namespace llvm::orc;
-
-namespace {
-
-// FIXME: This class is only here to support the transition to llvm::Error. It
-// will be removed once this transition is complete. Clients should prefer to
-// deal with the Error value directly, rather than converting to error_code.
-class OrcErrorCategory : public std::error_category {
-public:
-  const char *name() const noexcept override { return "orc"; }
-
-  std::string message(int condition) const override {
-    switch (static_cast<OrcErrorCode>(condition)) {
-    case OrcErrorCode::UnknownORCError:
-      return "Unknown ORC error";
-    case OrcErrorCode::DuplicateDefinition:
-      return "Duplicate symbol definition";
-    case OrcErrorCode::JITSymbolNotFound:
-      return "JIT symbol not found";
-    case OrcErrorCode::RemoteAllocatorDoesNotExist:
-      return "Remote allocator does not exist";
-    case OrcErrorCode::RemoteAllocatorIdAlreadyInUse:
-      return "Remote allocator Id already in use";
-    case OrcErrorCode::RemoteMProtectAddrUnrecognized:
-      return "Remote mprotect call references unallocated memory";
-    case OrcErrorCode::RemoteIndirectStubsOwnerDoesNotExist:
-      return "Remote indirect stubs owner does not exist";
-    case OrcErrorCode::RemoteIndirectStubsOwnerIdAlreadyInUse:
-      return "Remote indirect stubs owner Id already in use";
-    case OrcErrorCode::RPCConnectionClosed:
-      return "RPC connection closed";
-    case OrcErrorCode::RPCCouldNotNegotiateFunction:
-      return "Could not negotiate RPC function";
-    case OrcErrorCode::RPCResponseAbandoned:
-      return "RPC response abandoned";
-    case OrcErrorCode::UnexpectedRPCCall:
-      return "Unexpected RPC call";
-    case OrcErrorCode::UnexpectedRPCResponse:
-      return "Unexpected RPC response";
-    case OrcErrorCode::UnknownErrorCodeFromRemote:
-      return "Unknown error returned from remote RPC function "
-             "(Use StringError to get error message)";
-    case OrcErrorCode::UnknownResourceHandle:
-      return "Unknown resource handle";
-    }
-    llvm_unreachable("Unhandled error code");
-  }
-};
-
-static ManagedStatic<OrcErrorCategory> OrcErrCat;
-}
-
-namespace llvm {
-namespace orc {
-
-char DuplicateDefinition::ID = 0;
-char JITSymbolNotFound::ID = 0;
-
-std::error_code orcError(OrcErrorCode ErrCode) {
-  typedef std::underlying_type<OrcErrorCode>::type UT;
-  return std::error_code(static_cast<UT>(ErrCode), *OrcErrCat);
-}
-
-
-DuplicateDefinition::DuplicateDefinition(std::string SymbolName)
-  : SymbolName(std::move(SymbolName)) {}
-
-std::error_code DuplicateDefinition::convertToErrorCode() const {
-  return orcError(OrcErrorCode::DuplicateDefinition);
-}
-
-void DuplicateDefinition::log(raw_ostream &OS) const {
-  OS << "Duplicate definition of symbol '" << SymbolName << "'";
-}
-
-const std::string &DuplicateDefinition::getSymbolName() const {
-  return SymbolName;
-}
-
-JITSymbolNotFound::JITSymbolNotFound(std::string SymbolName)
-  : SymbolName(std::move(SymbolName)) {}
-
-std::error_code JITSymbolNotFound::convertToErrorCode() const {
-  typedef std::underlying_type<OrcErrorCode>::type UT;
-  return std::error_code(static_cast<UT>(OrcErrorCode::JITSymbolNotFound),
-                         *OrcErrCat);
-}
-
-void JITSymbolNotFound::log(raw_ostream &OS) const {
-  OS << "Could not find symbol '" << SymbolName << "'";
-}
-
-const std::string &JITSymbolNotFound::getSymbolName() const {
-  return SymbolName;
-}
-
-}
-}
diff --git a/llvm/lib/ExecutionEngine/Orc/RPCUtils.cpp b/llvm/lib/ExecutionEngine/Orc/RPCUtils.cpp
deleted file mode 100644
index 367b3639f84..00000000000
--- a/llvm/lib/ExecutionEngine/Orc/RPCUtils.cpp
+++ /dev/null
@@ -1,54 +0,0 @@
-//===--------------- RPCUtils.cpp - RPCUtils implementation ---------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-//
-// RPCUtils implementation.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ExecutionEngine/Orc/RPCUtils.h"
-
-char llvm::orc::rpc::RPCFatalError::ID = 0;
-char llvm::orc::rpc::ConnectionClosed::ID = 0;
-char llvm::orc::rpc::ResponseAbandoned::ID = 0;
-char llvm::orc::rpc::CouldNotNegotiate::ID = 0;
-
-namespace llvm {
-namespace orc {
-namespace rpc {
-
-std::error_code ConnectionClosed::convertToErrorCode() const {
-  return orcError(OrcErrorCode::RPCConnectionClosed);
-}
-
-void ConnectionClosed::log(raw_ostream &OS) const {
-  OS << "RPC connection already closed";
-}
-
-std::error_code ResponseAbandoned::convertToErrorCode() const {
-  return orcError(OrcErrorCode::RPCResponseAbandoned);
-}
-
-void ResponseAbandoned::log(raw_ostream &OS) const {
-  OS << "RPC response abandoned";
-}
-
-CouldNotNegotiate::CouldNotNegotiate(std::string Signature)
-    : Signature(std::move(Signature)) {}
-
-std::error_code CouldNotNegotiate::convertToErrorCode() const {
-  return orcError(OrcErrorCode::RPCCouldNotNegotiateFunction);
-}
-
-void CouldNotNegotiate::log(raw_ostream &OS) const {
-  OS << "Could not negotiate RPC function " << Signature;
-}
-
-
-} // end namespace rpc
-} // end namespace orc
-} // end namespace llvm
diff --git a/llvm/lib/ExecutionEngine/OrcError/CMakeLists.txt b/llvm/lib/ExecutionEngine/OrcError/CMakeLists.txt
new file mode 100644
index 00000000000..7273a33030e
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/OrcError/CMakeLists.txt
@@ -0,0 +1,6 @@
+add_llvm_library(LLVMOrcError
+  OrcError.cpp
+  RPCError.cpp
+  ADDITIONAL_HEADER_DIRS
+  ${LLVM_MAIN_INCLUDE_DIR}/llvm/ExecutionEngine/Orc
+  )
diff --git a/llvm/lib/ExecutionEngine/OrcError/LLVMBuild.txt b/llvm/lib/ExecutionEngine/OrcError/LLVMBuild.txt
new file mode 100644
index 00000000000..65e7916916f
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/OrcError/LLVMBuild.txt
@@ -0,0 +1,21 @@
+;===- ./lib/ExecutionEngine/OrcError/LLVMBuild.txt -------------*- Conf -*--===;
+;
+; 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 is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = OrcError
+parent = ExecutionEngine
+required_libraries = Support
diff --git a/llvm/lib/ExecutionEngine/OrcError/OrcError.cpp b/llvm/lib/ExecutionEngine/OrcError/OrcError.cpp
new file mode 100644
index 00000000000..e6e9a095319
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/OrcError/OrcError.cpp
@@ -0,0 +1,115 @@
+//===---------------- OrcError.cpp - Error codes for ORC ------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Error codes for ORC.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ExecutionEngine/Orc/OrcError.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ManagedStatic.h"
+
+using namespace llvm;
+using namespace llvm::orc;
+
+namespace {
+
+// FIXME: This class is only here to support the transition to llvm::Error. It
+// will be removed once this transition is complete. Clients should prefer to
+// deal with the Error value directly, rather than converting to error_code.
+class OrcErrorCategory : public std::error_category {
+public:
+  const char *name() const noexcept override { return "orc"; }
+
+  std::string message(int condition) const override {
+    switch (static_cast<OrcErrorCode>(condition)) {
+    case OrcErrorCode::UnknownORCError:
+      return "Unknown ORC error";
+    case OrcErrorCode::DuplicateDefinition:
+      return "Duplicate symbol definition";
+    case OrcErrorCode::JITSymbolNotFound:
+      return "JIT symbol not found";
+    case OrcErrorCode::RemoteAllocatorDoesNotExist:
+      return "Remote allocator does not exist";
+    case OrcErrorCode::RemoteAllocatorIdAlreadyInUse:
+      return "Remote allocator Id already in use";
+    case OrcErrorCode::RemoteMProtectAddrUnrecognized:
+      return "Remote mprotect call references unallocated memory";
+    case OrcErrorCode::RemoteIndirectStubsOwnerDoesNotExist:
+      return "Remote indirect stubs owner does not exist";
+    case OrcErrorCode::RemoteIndirectStubsOwnerIdAlreadyInUse:
+      return "Remote indirect stubs owner Id already in use";
+    case OrcErrorCode::RPCConnectionClosed:
+      return "RPC connection closed";
+    case OrcErrorCode::RPCCouldNotNegotiateFunction:
+      return "Could not negotiate RPC function";
+    case OrcErrorCode::RPCResponseAbandoned:
+      return "RPC response abandoned";
+    case OrcErrorCode::UnexpectedRPCCall:
+      return "Unexpected RPC call";
+    case OrcErrorCode::UnexpectedRPCResponse:
+      return "Unexpected RPC response";
+    case OrcErrorCode::UnknownErrorCodeFromRemote:
+      return "Unknown error returned from remote RPC function "
+             "(Use StringError to get error message)";
+    case OrcErrorCode::UnknownResourceHandle:
+      return "Unknown resource handle";
+    }
+    llvm_unreachable("Unhandled error code");
+  }
+};
+
+static ManagedStatic<OrcErrorCategory> OrcErrCat;
+}
+
+namespace llvm {
+namespace orc {
+
+char DuplicateDefinition::ID = 0;
+char JITSymbolNotFound::ID = 0;
+
+std::error_code orcError(OrcErrorCode ErrCode) {
+  typedef std::underlying_type<OrcErrorCode>::type UT;
+  return std::error_code(static_cast<UT>(ErrCode), *OrcErrCat);
+}
+
+
+DuplicateDefinition::DuplicateDefinition(std::string SymbolName)
+  : SymbolName(std::move(SymbolName)) {}
+
+std::error_code DuplicateDefinition::convertToErrorCode() const {
+  return orcError(OrcErrorCode::DuplicateDefinition);
+}
+
+void DuplicateDefinition::log(raw_ostream &OS) const {
+  OS << "Duplicate definition of symbol '" << SymbolName << "'";
+}
+
+const std::string &DuplicateDefinition::getSymbolName() const {
+  return SymbolName;
+}
+
+JITSymbolNotFound::JITSymbolNotFound(std::string SymbolName)
+  : SymbolName(std::move(SymbolName)) {}
+
+std::error_code JITSymbolNotFound::convertToErrorCode() const {
+  typedef std::underlying_type<OrcErrorCode>::type UT;
+  return std::error_code(static_cast<UT>(OrcErrorCode::JITSymbolNotFound),
+                         *OrcErrCat);
+}
+
+void JITSymbolNotFound::log(raw_ostream &OS) const {
+  OS << "Could not find symbol '" << SymbolName << "'";
+}
+
+const std::string &JITSymbolNotFound::getSymbolName() const {
+  return SymbolName;
+}
+
+}
+}
diff --git a/llvm/lib/ExecutionEngine/OrcError/RPCError.cpp b/llvm/lib/ExecutionEngine/OrcError/RPCError.cpp
new file mode 100644
index 00000000000..b77a526f571
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/OrcError/RPCError.cpp
@@ -0,0 +1,54 @@
+//===--------------- RPCError.cpp - RPCERror implementation ---------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// RPC Error type implmentations.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ExecutionEngine/Orc/RPC/RPCUtils.h"
+
+char llvm::orc::rpc::RPCFatalError::ID = 0;
+char llvm::orc::rpc::ConnectionClosed::ID = 0;
+char llvm::orc::rpc::ResponseAbandoned::ID = 0;
+char llvm::orc::rpc::CouldNotNegotiate::ID = 0;
+
+namespace llvm {
+namespace orc {
+namespace rpc {
+
+std::error_code ConnectionClosed::convertToErrorCode() const {
+  return orcError(OrcErrorCode::RPCConnectionClosed);
+}
+
+void ConnectionClosed::log(raw_ostream &OS) const {
+  OS << "RPC connection already closed";
+}
+
+std::error_code ResponseAbandoned::convertToErrorCode() const {
+  return orcError(OrcErrorCode::RPCResponseAbandoned);
+}
+
+void ResponseAbandoned::log(raw_ostream &OS) const {
+  OS << "RPC response abandoned";
+}
+
+CouldNotNegotiate::CouldNotNegotiate(std::string Signature)
+    : Signature(std::move(Signature)) {}
+
+std::error_code CouldNotNegotiate::convertToErrorCode() const {
+  return orcError(OrcErrorCode::RPCCouldNotNegotiateFunction);
+}
+
+void CouldNotNegotiate::log(raw_ostream &OS) const {
+  OS << "Could not negotiate RPC function " << Signature;
+}
+
+
+} // end namespace rpc
+} // end namespace orc
+} // end namespace llvm
diff --git a/llvm/tools/lli/RemoteJITUtils.h b/llvm/tools/lli/RemoteJITUtils.h
index 8e80e73c808..cc93294af0c 100644
--- a/llvm/tools/lli/RemoteJITUtils.h
+++ b/llvm/tools/lli/RemoteJITUtils.h
@@ -13,7 +13,7 @@
 #ifndef LLVM_TOOLS_LLI_REMOTEJITUTILS_H
 #define LLVM_TOOLS_LLI_REMOTEJITUTILS_H
 
-#include "llvm/ExecutionEngine/Orc/RawByteChannel.h"
+#include "llvm/ExecutionEngine/Orc/RPC/RawByteChannel.h"
 #include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
 #include <mutex>
 
diff --git a/llvm/unittests/ExecutionEngine/Orc/QueueChannel.h b/llvm/unittests/ExecutionEngine/Orc/QueueChannel.h
index caf696987bf..fabe2d11fe9 100644
--- a/llvm/unittests/ExecutionEngine/Orc/QueueChannel.h
+++ b/llvm/unittests/ExecutionEngine/Orc/QueueChannel.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_UNITTESTS_EXECUTIONENGINE_ORC_QUEUECHANNEL_H
 #define LLVM_UNITTESTS_EXECUTIONENGINE_ORC_QUEUECHANNEL_H
 
-#include "llvm/ExecutionEngine/Orc/RawByteChannel.h"
+#include "llvm/ExecutionEngine/Orc/RPC/RawByteChannel.h"
 #include "llvm/Support/Error.h"
 
 #include <atomic>
diff --git a/llvm/unittests/ExecutionEngine/Orc/RPCUtilsTest.cpp b/llvm/unittests/ExecutionEngine/Orc/RPCUtilsTest.cpp
index 2a0ed077252..734511bf33a 100644
--- a/llvm/unittests/ExecutionEngine/Orc/RPCUtilsTest.cpp
+++ b/llvm/unittests/ExecutionEngine/Orc/RPCUtilsTest.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/ExecutionEngine/Orc/RPCUtils.h"
+#include "llvm/ExecutionEngine/Orc/RPC/RPCUtils.h"
 #include "QueueChannel.h"
 #include "gtest/gtest.h"
 
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