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diff --git a/tools/dsymutil/BinaryHolder.h b/tools/dsymutil/BinaryHolder.h
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+//===-- BinaryHolder.h - Utility class for accessing binaries -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This program is a utility that aims to be a dropin replacement for
+// Darwin's dsymutil.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_TOOLS_DSYMUTIL_BINARYHOLDER_H
+#define LLVM_TOOLS_DSYMUTIL_BINARYHOLDER_H
+
+#include "llvm/Object/Archive.h"
+#include "llvm/Object/Error.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/ErrorOr.h"
+
+namespace llvm {
+namespace dsymutil {
+
+/// \brief The BinaryHolder class is responsible for creating and
+/// owning ObjectFile objects and their underlying MemoryBuffer. This
+/// is different from a simple OwningBinary in that it handles
+/// accessing to archive members.
+///
+/// As an optimization, this class will reuse an already mapped and
+/// parsed Archive object if 2 successive requests target the same
+/// archive file (Which is always the case in debug maps).
+/// Currently it only owns one memory buffer at any given time,
+/// meaning that a mapping request will invalidate the previous memory
+/// mapping.
+class BinaryHolder {
+  std::unique_ptr<object::Archive> CurrentArchive;
+  std::unique_ptr<MemoryBuffer> CurrentMemoryBuffer;
+  std::unique_ptr<object::ObjectFile> CurrentObjectFile;
+  bool Verbose;
+
+  /// \brief Get the MemoryBufferRef for the file specification in \p
+  /// Filename from the current archive.
+  ///
+  /// This function performs no system calls, it just looks up a
+  /// potential match for the given \p Filename in the currently
+  /// mapped archive if there is one.
+  ErrorOr<MemoryBufferRef> GetArchiveMemberBuffer(StringRef Filename);
+
+  /// \brief Interpret Filename as an archive member specification,
+  /// map the corresponding archive to memory and return the
+  /// MemoryBufferRef corresponding to the described member.
+  ErrorOr<MemoryBufferRef> MapArchiveAndGetMemberBuffer(StringRef Filename);
+
+  /// \brief Return the MemoryBufferRef that holds the memory
+  /// mapping for the given \p Filename. This function will try to
+  /// parse archive member specifications of the form
+  /// /path/to/archive.a(member.o).
+  ///
+  /// The returned MemoryBufferRef points to a buffer owned by this
+  /// object. The buffer is valid until the next call to
+  /// GetMemoryBufferForFile() on this object.
+  ErrorOr<MemoryBufferRef> GetMemoryBufferForFile(StringRef Filename);
+
+public:
+  BinaryHolder(bool Verbose) : Verbose(Verbose) {}
+
+  /// \brief Get the ObjectFile designated by the \p Filename. This
+  /// might be an archive member specification of the form
+  /// /path/to/archive.a(member.o).
+  ///
+  /// Calling this function invalidates the previous mapping owned by
+  /// the BinaryHolder.
+  ErrorOr<const object::ObjectFile &> GetObjectFile(StringRef Filename);
+
+  /// \brief Wraps GetObjectFile() to return a derived ObjectFile type.
+  template <typename ObjectFileType>
+  ErrorOr<const ObjectFileType &> GetFileAs(StringRef Filename) {
+    auto ErrOrObjFile = GetObjectFile(Filename);
+    if (auto Err = ErrOrObjFile.getError())
+      return Err;
+    if (const auto *Derived = dyn_cast<ObjectFileType>(CurrentObjectFile.get()))
+      return *Derived;
+    return make_error_code(object::object_error::invalid_file_type);
+  }
+
+  /// \brief Access the currently owned ObjectFile. As successfull
+  /// call to GetObjectFile() or GetFileAs() must have been performed
+  /// before calling this.
+  const object::ObjectFile &Get() {
+    assert(CurrentObjectFile);
+    return *CurrentObjectFile;
+  }
+
+  /// \brief Access to a derived version of the currently owned
+  /// ObjectFile. The conversion must be known to be valid.
+  template <typename ObjectFileType> const ObjectFileType &GetAs() {
+    return cast<ObjectFileType>(*CurrentObjectFile);
+  }
+};
+}
+}
+#endif