mirror of
https://sourceware.org/git/binutils-gdb.git
synced 2024-12-09 04:21:49 +08:00
6feae66da1
When building gdb with -std=c++20, I run into:
...
gdbsupport/default-init-alloc.h:52:12: error: ‘construct’ has not been \
declared in ‘class std::allocator<unsigned char>’
52 | using A::construct;
| ^~~~~~~~~
...
Indeed, std::allocator::construct has been deprecated in c++17 and removed in
c++20.
Fix this by using instead std::pmr::polymorphic_allocator for c++20.
Tested on x86_64-linux.
79 lines
2.3 KiB
C++
79 lines
2.3 KiB
C++
/* Copyright (C) 2017-2023 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_DEFAULT_INIT_ALLOC_H
|
|
#define COMMON_DEFAULT_INIT_ALLOC_H
|
|
|
|
#if __cplusplus >= 202002L
|
|
#include <memory_resource>
|
|
#endif
|
|
|
|
namespace gdb {
|
|
|
|
/* An allocator that default constructs using default-initialization
|
|
rather than value-initialization. The idea is to use this when you
|
|
don't want to default construct elements of containers of trivial
|
|
types using zero-initialization. */
|
|
|
|
/* Mostly as implementation convenience, this is implemented as an
|
|
adapter that given an allocator A, overrides 'A::construct()'. 'A'
|
|
defaults to std::allocator<T>. */
|
|
|
|
template<typename T,
|
|
typename A
|
|
#if __cplusplus >= 202002L
|
|
= std::pmr::polymorphic_allocator<T>
|
|
#else
|
|
= std::allocator<T>
|
|
#endif
|
|
>
|
|
class default_init_allocator : public A
|
|
{
|
|
public:
|
|
/* Pull in A's ctors. */
|
|
using A::A;
|
|
|
|
/* Override rebind. */
|
|
template<typename U>
|
|
struct rebind
|
|
{
|
|
/* A couple helpers just to make it a bit more readable. */
|
|
typedef std::allocator_traits<A> traits_;
|
|
typedef typename traits_::template rebind_alloc<U> alloc_;
|
|
|
|
/* This is what we're after. */
|
|
typedef default_init_allocator<U, alloc_> other;
|
|
};
|
|
|
|
/* Make the base allocator's construct method(s) visible. */
|
|
using A::construct;
|
|
|
|
/* .. and provide an override/overload for the case of default
|
|
construction (i.e., no arguments). This is where we construct
|
|
with default-init. */
|
|
template <typename U>
|
|
void construct (U *ptr)
|
|
noexcept (std::is_nothrow_default_constructible<U>::value)
|
|
{
|
|
::new ((void *) ptr) U; /* default-init */
|
|
}
|
|
};
|
|
|
|
} /* namespace gdb */
|
|
|
|
#endif /* COMMON_DEFAULT_INIT_ALLOC_H */
|