/* Caching of GDB/DWARF index files. Copyright (C) 2018-2019 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 "gdbsupport/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 */