diff options
author | Pedro Alves <palves@redhat.com> | 2017-12-08 22:44:12 +0000 |
---|---|---|
committer | Pedro Alves <palves@redhat.com> | 2017-12-08 23:37:30 +0000 |
commit | e5fa6583a7b1e5e0e0f33a4964a1f271e189cf35 (patch) | |
tree | 045c2a6d6b41858c0196bf5cf4ee803a218959df /gdb/common/hash_enum.h | |
parent | 4b514bc80885fa91e57b9d80f74ea267df343c46 (diff) | |
download | gdb-e5fa6583a7b1e5e0e0f33a4964a1f271e189cf35.zip gdb-e5fa6583a7b1e5e0e0f33a4964a1f271e189cf35.tar.gz gdb-e5fa6583a7b1e5e0e0f33a4964a1f271e189cf35.tar.bz2 |
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.
Diffstat (limited to 'gdb/common/hash_enum.h')
-rw-r--r-- | gdb/common/hash_enum.h | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/gdb/common/hash_enum.h b/gdb/common/hash_enum.h new file mode 100644 index 0000000..0ea3221 --- /dev/null +++ b/gdb/common/hash_enum.h @@ -0,0 +1,45 @@ +/* A hasher for enums. + + Copyright (C) 2017 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 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 */ |