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/* DWARF abbrev table cache
Copyright (C) 2022-2024 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 GDB_DWARF2_ABBREV_TABLE_CACHE_H
#define GDB_DWARF2_ABBREV_TABLE_CACHE_H
#include "dwarf2/abbrev.h"
#include "gdbsupport/unordered_set.h"
/* An abbrev table cache holds abbrev tables for easier reuse. */
class abbrev_table_cache
{
public:
abbrev_table_cache () = default;
DISABLE_COPY_AND_ASSIGN (abbrev_table_cache);
/* Find an abbrev table coming from the abbrev section SECTION at
offset OFFSET. Return the table, or nullptr if it has not yet
been registered. */
const abbrev_table *find (dwarf2_section_info *section,
sect_offset offset) const
{
abbrev_table_search_key key {section, offset};
if (auto iter = m_tables.find (key);
iter != m_tables.end ())
return iter->get ();
return nullptr;
}
/* Add TABLE to this cache. Ownership of TABLE is transferred to
the cache. Note that a table at a given section+offset may only
be registered once -- a violation of this will cause an assert.
To avoid this, call the 'find' method first, to see if the table
has already been read. */
void add (abbrev_table_up table);
private:
/* Key used to search for an existing abbrev table in M_TABLES. */
struct abbrev_table_search_key
{
const dwarf2_section_info *section;
sect_offset sect_off;
};
struct abbrev_table_hash
{
using is_transparent = void;
std::size_t operator() (const abbrev_table_search_key &key) const noexcept
{
return (std::hash<const dwarf2_section_info *> () (key.section)
+ (std::hash<std::underlying_type_t<decltype (key.sect_off)>> ()
(to_underlying (key.sect_off))));
}
std::size_t operator() (const abbrev_table_up &table) const noexcept
{ return (*this) ({ table->section, table->sect_off }); }
};
struct abbrev_table_eq
{
using is_transparent = void;
bool operator() (const abbrev_table_search_key &key,
const abbrev_table_up &table) const noexcept
{ return key.section == table->section && key.sect_off == table->sect_off; }
bool operator() (const abbrev_table_up &lhs,
const abbrev_table_up &rhs) const noexcept
{ return (*this) ({ lhs->section, lhs->sect_off }, rhs); }
};
/* Hash table of abbrev tables. */
gdb::unordered_set<abbrev_table_up, abbrev_table_hash, abbrev_table_eq> m_tables;
};
#endif /* GDB_DWARF2_ABBREV_TABLE_CACHE_H */
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