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Diffstat (limited to 'gdb/dwarf-index-cache.h')
-rw-r--r-- | gdb/dwarf-index-cache.h | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/gdb/dwarf-index-cache.h b/gdb/dwarf-index-cache.h new file mode 100644 index 0000000..b4fa8c4 --- /dev/null +++ b/gdb/dwarf-index-cache.h @@ -0,0 +1,112 @@ +/* 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 */ |