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diff --git a/include/clang/Serialization/PCHContainerOperations.h b/include/clang/Serialization/PCHContainerOperations.h
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index 0000000000000..2a91d9830af3c
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+++ b/include/clang/Serialization/PCHContainerOperations.h
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+//===--- Serialization/PCHContainerOperations.h - PCH Containers --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_SERIALIZATION_PCHCONTAINEROPERATIONS_H
+#define LLVM_CLANG_SERIALIZATION_PCHCONTAINEROPERATIONS_H
+
+#include "clang/Basic/Module.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include <memory>
+
+namespace llvm {
+class raw_pwrite_stream;
+}
+
+namespace clang {
+
+class ASTConsumer;
+class CodeGenOptions;
+class DiagnosticsEngine;
+class CompilerInstance;
+
+struct PCHBuffer {
+  ASTFileSignature Signature;
+  llvm::SmallVector<char, 0> Data;
+  bool IsComplete;
+};
+
+/// This abstract interface provides operations for creating
+/// containers for serialized ASTs (precompiled headers and clang
+/// modules).
+class PCHContainerWriter {
+public:
+  virtual ~PCHContainerWriter() = 0;
+  virtual llvm::StringRef getFormat() const = 0;
+
+  /// Return an ASTConsumer that can be chained with a
+  /// PCHGenerator that produces a wrapper file format containing a
+  /// serialized AST bitstream.
+  virtual std::unique_ptr<ASTConsumer>
+  CreatePCHContainerGenerator(CompilerInstance &CI,
+                              const std::string &MainFileName,
+                              const std::string &OutputFileName,
+                              std::unique_ptr<llvm::raw_pwrite_stream> OS,
+                              std::shared_ptr<PCHBuffer> Buffer) const = 0;
+};
+
+/// This abstract interface provides operations for unwrapping
+/// containers for serialized ASTs (precompiled headers and clang
+/// modules).
+class PCHContainerReader {
+public:
+  virtual ~PCHContainerReader() = 0;
+  /// Equivalent to the format passed to -fmodule-format=
+  virtual llvm::StringRef getFormat() const = 0;
+
+  /// Returns the serialized AST inside the PCH container Buffer.
+  virtual llvm::StringRef ExtractPCH(llvm::MemoryBufferRef Buffer) const = 0;
+};
+
+/// Implements write operations for a raw pass-through PCH container.
+class RawPCHContainerWriter : public PCHContainerWriter {
+  llvm::StringRef getFormat() const override { return "raw"; }
+
+  /// Return an ASTConsumer that can be chained with a
+  /// PCHGenerator that writes the module to a flat file.
+  std::unique_ptr<ASTConsumer>
+  CreatePCHContainerGenerator(CompilerInstance &CI,
+                              const std::string &MainFileName,
+                              const std::string &OutputFileName,
+                              std::unique_ptr<llvm::raw_pwrite_stream> OS,
+                              std::shared_ptr<PCHBuffer> Buffer) const override;
+};
+
+/// Implements read operations for a raw pass-through PCH container.
+class RawPCHContainerReader : public PCHContainerReader {
+  llvm::StringRef getFormat() const override { return "raw"; }
+
+  /// Simply returns the buffer contained in Buffer.
+  llvm::StringRef ExtractPCH(llvm::MemoryBufferRef Buffer) const override;
+};
+
+/// A registry of PCHContainerWriter and -Reader objects for different formats.
+class PCHContainerOperations {
+  llvm::StringMap<std::unique_ptr<PCHContainerWriter>> Writers;
+  llvm::StringMap<std::unique_ptr<PCHContainerReader>> Readers;
+public:
+  /// Automatically registers a RawPCHContainerWriter and
+  /// RawPCHContainerReader.
+  PCHContainerOperations();
+  void registerWriter(std::unique_ptr<PCHContainerWriter> Writer) {
+    Writers[Writer->getFormat()] = std::move(Writer);
+  }
+  void registerReader(std::unique_ptr<PCHContainerReader> Reader) {
+    Readers[Reader->getFormat()] = std::move(Reader);
+  }
+  const PCHContainerWriter *getWriterOrNull(llvm::StringRef Format) {
+    return Writers[Format].get();
+  }
+  const PCHContainerReader *getReaderOrNull(llvm::StringRef Format) {
+    return Readers[Format].get();
+  }
+  const PCHContainerReader &getRawReader() {
+    return *getReaderOrNull("raw");
+  }
+};
+
+}
+
+#endif