binutils-gdb/gdb/common/hash_enum.h

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Add gdb::hash_enum The DWARF-5 .debug_names consumer patch will want to use an std::unordered_map with an enum as key type, like: std::unordered_map<sect_offset, dwarf2_per_cu_data*> That doesn't work in C++11 in non-recent compilers due to a language defect: http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2148 ~~~ In file included from /usr/include/c++/5.3.1/bits/hashtable.h:35:0, from /usr/include/c++/5.3.1/unordered_set:47, from src/gdb/dwarf2read.c:79: /usr/include/c++/5.3.1/bits/hashtable_policy.h: In instantiation of ‘struct std::__detail::__is_noexcept_hash<sect_offset, std::hash<sect_offset> >’: /usr/include/c++/5.3.1/type_traits:137:12: required from ‘struct std::__and_<std::__is_fast_hash<std::hash<sect_offset> >, std::__detail::__is_noexcept_hash<sect_offset, std::hash<sect_offset> > >’ /usr/include/c++/5.3.1/type_traits:148:38: required from ‘struct std::__not_<std::__and_<std::__is_fast_hash<std::hash<sect_offset> >, std::__detail::__is_noexcept_hash<sect_offset, std::hash<sect_offset> > > >’ /usr/include/c++/5.3.1/bits/unordered_map.h:100:66: required from ‘class std::unordered_map<sect_offset, dwarf2_per_cu_data*>’ src/gdb/dwarf2read.c:3260:30: required from here /usr/include/c++/5.3.1/bits/hashtable_policy.h:85:34: error: no match for call to ‘(const std::hash<sect_offset>) (const sect_offset&)’ noexcept(declval<const _Hash&>()(declval<const _Key&>()))> ^ In file included from /usr/include/c++/5.3.1/bits/move.h:57:0, from /usr/include/c++/5.3.1/bits/stl_pair.h:59, from /usr/include/c++/5.3.1/bits/stl_algobase.h:64, from /usr/include/c++/5.3.1/bits/char_traits.h:39, from /usr/include/c++/5.3.1/string:40, from /home/pedro/gdb/mygit/src/gdb/common/common-utils.h:23, from /home/pedro/gdb/mygit/src/gdb/common/common-defs.h:78, from /home/pedro/gdb/mygit/src/gdb/defs.h:28, from /home/pedro/gdb/mygit/src/gdb/dwarf2read.c:31: ~~~ This commits adds a helper replacement. gdb/ChangeLog: 2017-12-08 Pedro Alves <palves@redhat.com> * common/hash_enum.h: New file.
2017-12-08 23:44:12 +01:00
/* A hasher for enums.
Copyright (C) 2017-2018 Free Software Foundation, Inc.
Add gdb::hash_enum The DWARF-5 .debug_names consumer patch will want to use an std::unordered_map with an enum as key type, like: std::unordered_map<sect_offset, dwarf2_per_cu_data*> That doesn't work in C++11 in non-recent compilers due to a language defect: http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2148 ~~~ In file included from /usr/include/c++/5.3.1/bits/hashtable.h:35:0, from /usr/include/c++/5.3.1/unordered_set:47, from src/gdb/dwarf2read.c:79: /usr/include/c++/5.3.1/bits/hashtable_policy.h: In instantiation of ‘struct std::__detail::__is_noexcept_hash<sect_offset, std::hash<sect_offset> >’: /usr/include/c++/5.3.1/type_traits:137:12: required from ‘struct std::__and_<std::__is_fast_hash<std::hash<sect_offset> >, std::__detail::__is_noexcept_hash<sect_offset, std::hash<sect_offset> > >’ /usr/include/c++/5.3.1/type_traits:148:38: required from ‘struct std::__not_<std::__and_<std::__is_fast_hash<std::hash<sect_offset> >, std::__detail::__is_noexcept_hash<sect_offset, std::hash<sect_offset> > > >’ /usr/include/c++/5.3.1/bits/unordered_map.h:100:66: required from ‘class std::unordered_map<sect_offset, dwarf2_per_cu_data*>’ src/gdb/dwarf2read.c:3260:30: required from here /usr/include/c++/5.3.1/bits/hashtable_policy.h:85:34: error: no match for call to ‘(const std::hash<sect_offset>) (const sect_offset&)’ noexcept(declval<const _Hash&>()(declval<const _Key&>()))> ^ In file included from /usr/include/c++/5.3.1/bits/move.h:57:0, from /usr/include/c++/5.3.1/bits/stl_pair.h:59, from /usr/include/c++/5.3.1/bits/stl_algobase.h:64, from /usr/include/c++/5.3.1/bits/char_traits.h:39, from /usr/include/c++/5.3.1/string:40, from /home/pedro/gdb/mygit/src/gdb/common/common-utils.h:23, from /home/pedro/gdb/mygit/src/gdb/common/common-defs.h:78, from /home/pedro/gdb/mygit/src/gdb/defs.h:28, from /home/pedro/gdb/mygit/src/gdb/dwarf2read.c:31: ~~~ This commits adds a helper replacement. gdb/ChangeLog: 2017-12-08 Pedro Alves <palves@redhat.com> * common/hash_enum.h: New file.
2017-12-08 23:44:12 +01:00
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 COMMON_HASH_ENUM_H
#define COMMON_HASH_ENUM_H
/* A hasher for enums, which was missing in C++11:
http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2148
*/
namespace gdb {
/* Helper struct for hashing enum types. */
template<typename T>
struct hash_enum
{
typedef size_t result_type;
typedef T argument_type;
size_t operator() (T val) const noexcept
{
using underlying = typename std::underlying_type<T>::type;
return std::hash<underlying> () (static_cast<underlying> (val));
}
};
} /* namespace gdb */
#endif /* COMMON_HASH_ENUM_H */