| Message ID | CAFk2RUbfaK=+i_6Gm9fcbZaXFJAC3HC5UDp4z9qd2cuxdzEiiA@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
On 2 April 2017 at 02:45, Ville Voutilainen <ville.voutilainen@gmail.com> wrote:
> Tested on Linux-x64.
For what it's worth, here's a saner changelog that uses the signatures
that were originally in place. The patch
passes the full testsuite on Linux-PPC64 without regressions.
2017-04-02 Ville Voutilainen <ville.voutilainen@gmail.com>
PR libstdc++/79141
* include/bits/stl_pair.h (__wrap_nonesuch): New.
(operator=(typename conditional<
__and_<is_copy_assignable<_T1>,
is_copy_assignable<_T2>>::value,
const pair&, const __nonesuch&>::type)): Change __nonesuch
to __wrap_nonesuch.
(operator=(typename conditional<
__not_<__and_<is_copy_assignable<_T1>,
is_copy_assignable<_T2>>>::value,
const pair&, const __nonesuch&>::type)): Likewise.
(operator=(typename conditional<
__and_<is_move_assignable<_T1>,
is_move_assignable<_T2>>::value,
pair&&, __nonesuch&&>::type)): Likewise.
* testsuite/20_util/pair/79141.cc: New.
On 02/04/17 02:45 +0300, Ville Voutilainen wrote: > PR libstdc++/79141 > * include/bits/stl_pair.h (__wrap_nonesuch): New. > (operator=(typename conditional< > __and_<is_copy_assignable<_T1>, > is_copy_assignable<_T2>>::value, > const pair&, const __wrap_nonesuch&>::type)): Change __nonesuch > to __wrap_nonesuch. > (operator=(typename conditional< > __not_<__and_<is_copy_assignable<_T1>, > is_copy_assignable<_T2>>>::value, > const pair&, const __nonesuch&>::type)): Likewise. > (operator=(typename conditional< > __and_<is_move_assignable<_T1>, > is_move_assignable<_T2>>::value, > pair&&, __wrap_nonesuch&&>::type)): Likewise. > * testsuite/20_util/pair/79141.cc: New. >diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h >index 7c7cee2..b746fb4 100644 >--- a/libstdc++-v3/include/bits/stl_pair.h >+++ b/libstdc++-v3/include/bits/stl_pair.h >@@ -179,6 +179,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > } > }; > >+ struct __wrap_nonesuch : std::__nonesuch { >+ explicit __wrap_nonesuch(const __nonesuch&) = delete; >+ }; Could you please add a comment explaining that this is needed to ensure that functions with parameters of this type are not viable when an argument of {} is used. Because even with such a comment I'll probably not understand this by next week. And I think __explicit_nonesuch or __no_list_init would be a clearer name. We're not really "wrapping" this, unless I misunderstand. OK for trunk, I suppose. This kind of thing is why I want to burn std::pair and std::tuple to the ground.
On 03/04/17 16:43 +0100, Jonathan Wakely wrote: >On 02/04/17 02:45 +0300, Ville Voutilainen wrote: >> PR libstdc++/79141 >> * include/bits/stl_pair.h (__wrap_nonesuch): New. >> (operator=(typename conditional< >> __and_<is_copy_assignable<_T1>, >> is_copy_assignable<_T2>>::value, >> const pair&, const __wrap_nonesuch&>::type)): Change __nonesuch >> to __wrap_nonesuch. >> (operator=(typename conditional< >> __not_<__and_<is_copy_assignable<_T1>, >> is_copy_assignable<_T2>>>::value, >> const pair&, const __nonesuch&>::type)): Likewise. >> (operator=(typename conditional< >> __and_<is_move_assignable<_T1>, >> is_move_assignable<_T2>>::value, >> pair&&, __wrap_nonesuch&&>::type)): Likewise. >> * testsuite/20_util/pair/79141.cc: New. > >>diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h >>index 7c7cee2..b746fb4 100644 >>--- a/libstdc++-v3/include/bits/stl_pair.h >>+++ b/libstdc++-v3/include/bits/stl_pair.h >>@@ -179,6 +179,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION >> } >> }; >> >>+ struct __wrap_nonesuch : std::__nonesuch { >>+ explicit __wrap_nonesuch(const __nonesuch&) = delete; >>+ }; > >Could you please add a comment explaining that this is needed to >ensure that functions with parameters of this type are not viable when >an argument of {} is used. Because even with such a comment I'll >probably not understand this by next week. > >And I think __explicit_nonesuch or __no_list_init would be a clearer >name. We're not really "wrapping" this, unless I misunderstand. > >OK for trunk, I suppose. Oh, and gcc-6-branch.
diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h index 7c7cee2..b746fb4 100644 --- a/libstdc++-v3/include/bits/stl_pair.h +++ b/libstdc++-v3/include/bits/stl_pair.h @@ -179,6 +179,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION } }; + struct __wrap_nonesuch : std::__nonesuch { + explicit __wrap_nonesuch(const __nonesuch&) = delete; + }; + #endif /** @@ -360,7 +364,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION operator=(typename conditional< __and_<is_copy_assignable<_T1>, is_copy_assignable<_T2>>::value, - const pair&, const __nonesuch&>::type __p) + const pair&, const __wrap_nonesuch&>::type __p) { first = __p.first; second = __p.second; @@ -371,13 +375,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION operator=(typename conditional< __not_<__and_<is_copy_assignable<_T1>, is_copy_assignable<_T2>>>::value, - const pair&, const __nonesuch&>::type __p) = delete; + const pair&, const __wrap_nonesuch&>::type __p) = delete; pair& operator=(typename conditional< __and_<is_move_assignable<_T1>, is_move_assignable<_T2>>::value, - pair&&, __nonesuch&&>::type __p) + pair&&, __wrap_nonesuch&&>::type __p) noexcept(__and_<is_nothrow_move_assignable<_T1>, is_nothrow_move_assignable<_T2>>::value) { diff --git a/libstdc++-v3/testsuite/20_util/pair/79141.cc b/libstdc++-v3/testsuite/20_util/pair/79141.cc new file mode 100644 index 0000000..d4b5c94 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/pair/79141.cc @@ -0,0 +1,25 @@ +// { dg-do compile { target c++11 } } + +// Copyright (C) 2017 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library 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, or (at your option) +// any later version. + +// This library 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 library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <utility> + +int main() { + std::pair<int,int> p; + p = {}; +}
Tested on Linux-x64. 2017-04-02 Ville Voutilainen <ville.voutilainen@gmail.com> PR libstdc++/79141 * include/bits/stl_pair.h (__wrap_nonesuch): New. (operator=(typename conditional< __and_<is_copy_assignable<_T1>, is_copy_assignable<_T2>>::value, const pair&, const __wrap_nonesuch&>::type)): Change __nonesuch to __wrap_nonesuch. (operator=(typename conditional< __not_<__and_<is_copy_assignable<_T1>, is_copy_assignable<_T2>>>::value, const pair&, const __nonesuch&>::type)): Likewise. (operator=(typename conditional< __and_<is_move_assignable<_T1>, is_move_assignable<_T2>>::value, pair&&, __wrap_nonesuch&&>::type)): Likewise. * testsuite/20_util/pair/79141.cc: New.