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diff --git a/gdb/dwarf-index-cache.h b/gdb/dwarf-index-cache.h
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+/* Caching of GDB/DWARF index files.
+
+   Copyright (C) 2018 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef DWARF_INDEX_CACHE_H
+#define DWARF_INDEX_CACHE_H
+
+#include "dwarf-index-common.h"
+#include "common/array-view.h"
+#include "symfile.h"
+
+/* Base of the classes used to hold the resources of the indices loaded from
+   the cache (e.g. mmapped files).  */
+
+struct index_cache_resource
+{
+  virtual ~index_cache_resource () = 0;
+};
+
+/* Class to manage the access to the DWARF index cache.  */
+
+class index_cache
+{
+public:
+  /* Change the directory used to save/load index files.  */
+  void set_directory (std::string dir);
+
+  /* Return true if the usage of the cache is enabled.  */
+  bool enabled () const
+  {
+    return m_enabled;
+  }
+
+  /* Enable the cache.  */
+  void enable ();
+
+  /* Disable the cache.  */
+  void disable ();
+
+  /* Store an index for the specified object file in the cache.  */
+  void store (struct dwarf2_per_objfile *dwarf2_per_objfile);
+
+  /* Look for an index file matching BUILD_ID.  If found, return the contents
+     as an array_view and store the underlying resources (allocated memory,
+     mapped file, etc) in RESOURCE.  The returned array_view is valid as long
+     as RESOURCE is not destroyed.
+
+     If no matching index file is found, return an empty array view.  */
+  gdb::array_view<const gdb_byte>
+  lookup_gdb_index (const bfd_build_id *build_id,
+		    std::unique_ptr<index_cache_resource> *resource);
+
+  /* Return the number of cache hits.  */
+  unsigned int n_hits () const
+  { return m_n_hits; }
+
+  /* Record a cache hit.  */
+  void hit ()
+  {
+    if (enabled ())
+      m_n_hits++;
+  }
+
+  /* Return the number of cache misses.  */
+  unsigned int n_misses () const
+  { return m_n_misses; }
+
+  /* Record a cache miss.  */
+  void miss ()
+  {
+    if (enabled ())
+      m_n_misses++;
+  }
+
+private:
+
+  /* Compute the absolute filename where the index of the objfile with build
+     id BUILD_ID will be stored.  SUFFIX is appended at the end of the
+     filename.  */
+  std::string make_index_filename (const bfd_build_id *build_id,
+				   const char *suffix) const;
+
+  /* The base directory where we are storing and looking up index files.  */
+  std::string m_dir;
+
+  /* Whether the cache is enabled.  */
+  bool m_enabled = false;
+
+  /* Number of cache hits and misses during this GDB session.  */
+  unsigned int m_n_hits = 0;
+  unsigned int m_n_misses = 0;
+};
+
+/* The global instance of the index cache.  */
+extern index_cache global_index_cache;
+
+#endif /* DWARF_INDEX_CACHE_H */