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113 lines
3.1 KiB
C++
113 lines
3.1 KiB
C++
/* Caching of GDB/DWARF index files.
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Copyright (C) 2018-2020 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef DWARF_INDEX_CACHE_H
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#define DWARF_INDEX_CACHE_H
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#include "dwarf-index-common.h"
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#include "gdbsupport/array-view.h"
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#include "symfile.h"
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/* Base of the classes used to hold the resources of the indices loaded from
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the cache (e.g. mmapped files). */
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struct index_cache_resource
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{
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virtual ~index_cache_resource () = 0;
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};
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/* Class to manage the access to the DWARF index cache. */
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class index_cache
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{
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public:
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/* Change the directory used to save/load index files. */
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void set_directory (std::string dir);
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/* Return true if the usage of the cache is enabled. */
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bool enabled () const
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{
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return m_enabled;
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}
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/* Enable the cache. */
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void enable ();
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/* Disable the cache. */
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void disable ();
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/* Store an index for the specified object file in the cache. */
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void store (struct dwarf2_per_objfile *dwarf2_per_objfile);
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/* Look for an index file matching BUILD_ID. If found, return the contents
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as an array_view and store the underlying resources (allocated memory,
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mapped file, etc) in RESOURCE. The returned array_view is valid as long
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as RESOURCE is not destroyed.
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If no matching index file is found, return an empty array view. */
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gdb::array_view<const gdb_byte>
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lookup_gdb_index (const bfd_build_id *build_id,
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std::unique_ptr<index_cache_resource> *resource);
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/* Return the number of cache hits. */
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unsigned int n_hits () const
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{ return m_n_hits; }
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/* Record a cache hit. */
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void hit ()
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{
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if (enabled ())
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m_n_hits++;
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}
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/* Return the number of cache misses. */
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unsigned int n_misses () const
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{ return m_n_misses; }
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/* Record a cache miss. */
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void miss ()
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{
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if (enabled ())
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m_n_misses++;
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}
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private:
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/* Compute the absolute filename where the index of the objfile with build
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id BUILD_ID will be stored. SUFFIX is appended at the end of the
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filename. */
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std::string make_index_filename (const bfd_build_id *build_id,
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const char *suffix) const;
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/* The base directory where we are storing and looking up index files. */
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std::string m_dir;
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/* Whether the cache is enabled. */
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bool m_enabled = false;
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/* Number of cache hits and misses during this GDB session. */
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unsigned int m_n_hits = 0;
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unsigned int m_n_misses = 0;
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};
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/* The global instance of the index cache. */
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extern index_cache global_index_cache;
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#endif /* DWARF_INDEX_CACHE_H */
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