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diff --git a/include/llvm/Support/BinaryByteStream.h b/include/llvm/Support/BinaryByteStream.h
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+++ b/include/llvm/Support/BinaryByteStream.h
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+//===- BinaryByteStream.h ---------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//===----------------------------------------------------------------------===//
+// A BinaryStream which stores data in a single continguous memory buffer.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_BINARYBYTESTREAM_H
+#define LLVM_SUPPORT_BINARYBYTESTREAM_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/BinaryStream.h"
+#include "llvm/Support/BinaryStreamError.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/FileOutputBuffer.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include <algorithm>
+#include <cstdint>
+#include <cstring>
+#include <memory>
+
+namespace llvm {
+
+/// \brief An implementation of BinaryStream which holds its entire data set
+/// in a single contiguous buffer.  BinaryByteStream guarantees that no read
+/// operation will ever incur a copy.  Note that BinaryByteStream does not
+/// own the underlying buffer.
+class BinaryByteStream : public BinaryStream {
+public:
+  BinaryByteStream() = default;
+  BinaryByteStream(ArrayRef<uint8_t> Data, llvm::support::endianness Endian)
+      : Endian(Endian), Data(Data) {}
+  BinaryByteStream(StringRef Data, llvm::support::endianness Endian)
+      : Endian(Endian), Data(Data.bytes_begin(), Data.bytes_end()) {}
+
+  llvm::support::endianness getEndian() const override { return Endian; }
+
+  Error readBytes(uint32_t Offset, uint32_t Size,
+                  ArrayRef<uint8_t> &Buffer) override {
+    if (auto EC = checkOffset(Offset, Size))
+      return EC;
+    Buffer = Data.slice(Offset, Size);
+    return Error::success();
+  }
+
+  Error readLongestContiguousChunk(uint32_t Offset,
+                                   ArrayRef<uint8_t> &Buffer) override {
+    if (auto EC = checkOffset(Offset, 1))
+      return EC;
+    Buffer = Data.slice(Offset);
+    return Error::success();
+  }
+
+  uint32_t getLength() override { return Data.size(); }
+
+  ArrayRef<uint8_t> data() const { return Data; }
+
+  StringRef str() const {
+    const char *CharData = reinterpret_cast<const char *>(Data.data());
+    return StringRef(CharData, Data.size());
+  }
+
+protected:
+  llvm::support::endianness Endian;
+  ArrayRef<uint8_t> Data;
+};
+
+/// \brief An implementation of BinaryStream whose data is backed by an llvm
+/// MemoryBuffer object.  MemoryBufferByteStream owns the MemoryBuffer in
+/// question.  As with BinaryByteStream, reading from a MemoryBufferByteStream
+/// will never cause a copy.
+class MemoryBufferByteStream : public BinaryByteStream {
+public:
+  MemoryBufferByteStream(std::unique_ptr<MemoryBuffer> Buffer,
+                         llvm::support::endianness Endian)
+      : BinaryByteStream(Buffer->getBuffer(), Endian),
+        MemBuffer(std::move(Buffer)) {}
+
+  std::unique_ptr<MemoryBuffer> MemBuffer;
+};
+
+/// \brief An implementation of BinaryStream which holds its entire data set
+/// in a single contiguous buffer.  As with BinaryByteStream, the mutable
+/// version also guarantees that no read operation will ever incur a copy,
+/// and similarly it does not own the underlying buffer.
+class MutableBinaryByteStream : public WritableBinaryStream {
+public:
+  MutableBinaryByteStream() = default;
+  MutableBinaryByteStream(MutableArrayRef<uint8_t> Data,
+                          llvm::support::endianness Endian)
+      : Data(Data), ImmutableStream(Data, Endian) {}
+
+  llvm::support::endianness getEndian() const override {
+    return ImmutableStream.getEndian();
+  }
+
+  Error readBytes(uint32_t Offset, uint32_t Size,
+                  ArrayRef<uint8_t> &Buffer) override {
+    return ImmutableStream.readBytes(Offset, Size, Buffer);
+  }
+
+  Error readLongestContiguousChunk(uint32_t Offset,
+                                   ArrayRef<uint8_t> &Buffer) override {
+    return ImmutableStream.readLongestContiguousChunk(Offset, Buffer);
+  }
+
+  uint32_t getLength() override { return ImmutableStream.getLength(); }
+
+  Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> Buffer) override {
+    if (Buffer.empty())
+      return Error::success();
+
+    if (auto EC = checkOffset(Offset, Buffer.size()))
+      return EC;
+
+    uint8_t *DataPtr = const_cast<uint8_t *>(Data.data());
+    ::memcpy(DataPtr + Offset, Buffer.data(), Buffer.size());
+    return Error::success();
+  }
+
+  Error commit() override { return Error::success(); }
+
+  MutableArrayRef<uint8_t> data() const { return Data; }
+
+private:
+  MutableArrayRef<uint8_t> Data;
+  BinaryByteStream ImmutableStream;
+};
+
+/// \brief An implementation of WritableBinaryStream backed by an llvm
+/// FileOutputBuffer.
+class FileBufferByteStream : public WritableBinaryStream {
+private:
+  class StreamImpl : public MutableBinaryByteStream {
+  public:
+    StreamImpl(std::unique_ptr<FileOutputBuffer> Buffer,
+               llvm::support::endianness Endian)
+        : MutableBinaryByteStream(
+              MutableArrayRef<uint8_t>(Buffer->getBufferStart(),
+                                       Buffer->getBufferEnd()),
+              Endian),
+          FileBuffer(std::move(Buffer)) {}
+
+    Error commit() override {
+      if (FileBuffer->commit())
+        return make_error<BinaryStreamError>(
+            stream_error_code::filesystem_error);
+      return Error::success();
+    }
+
+  private:
+    std::unique_ptr<FileOutputBuffer> FileBuffer;
+  };
+
+public:
+  FileBufferByteStream(std::unique_ptr<FileOutputBuffer> Buffer,
+                       llvm::support::endianness Endian)
+      : Impl(std::move(Buffer), Endian) {}
+
+  llvm::support::endianness getEndian() const override {
+    return Impl.getEndian();
+  }
+
+  Error readBytes(uint32_t Offset, uint32_t Size,
+                  ArrayRef<uint8_t> &Buffer) override {
+    return Impl.readBytes(Offset, Size, Buffer);
+  }
+
+  Error readLongestContiguousChunk(uint32_t Offset,
+                                   ArrayRef<uint8_t> &Buffer) override {
+    return Impl.readLongestContiguousChunk(Offset, Buffer);
+  }
+
+  uint32_t getLength() override { return Impl.getLength(); }
+
+  Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> Data) override {
+    return Impl.writeBytes(Offset, Data);
+  }
+
+  Error commit() override { return Impl.commit(); }
+
+private:
+  StreamImpl Impl;
+};
+
+} // end namespace llvm
+
+#endif // LLVM_SUPPORT_BYTESTREAM_H