On 21/02/19 20:47 +0000, Jonathan Wakely wrote:
On 05/02/19 14:45 +0000, Jonathan Wakely wrote:
This fixes two PRs, one trivial (don't use C++17 features in C++11
mode) and one more serious (don't require MoveInsertable when we
should only need CopyInsertable).
It would be nice to rely on if-constexpr in C++11 mode, but it causes
clang warnings, complicates testcase bisection/reduction, and causes
users to file bogus bug reports. So let's just avoid it.
Tested powerpc64le-linux, committed to trunk.
commit 51908e56bd32b5f89bc909193c3da957de01c3e0
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Tue Feb 5 11:50:18 2019 +0000
PR libstdc++/89130 restore support for non-MoveConstructible types
The changes to "relocate" std::vector elements can lead to new errors
outside the immediate context, because moving the elements to new
storage no longer makes use of the move-if-noexcept utilities. This
means that types with deleted moves no longer degenerate to copies, but
are just ill-formed. The errors happen while instantiating the
noexcept-specifier for __relocate_object_a, when deciding whether to try
to relocate.
This patch introduces indirections to avoid the ill-formed
instantiations of std::__relocate_object_a. In order to avoid using
if-constexpr prior to C++17 this is done by tag dispatching. After this
patch all uses of std::__relocate_a are guarded by checks that will
support sensible code (i.e. code not using custom allocators that fool
the new checks).
PR libstdc++/89130
* include/bits/alloc_traits.h (__is_copy_insertable_impl): Rename to
__is_alloc_insertable_impl. Replace single type member with two
members, one for each of copy and move insertable.
(__is_move_insertable): New trait for internal use.
* include/bits/stl_vector.h (vector::_S_nothrow_relocate(true_type))
(vector::_S_nothrow_relocate(true_type)): New functions to
conditionally check if __relocate_a can throw.
(vector::_S_use_relocate()): Dispatch to _S_nothrow_relocate based
on __is_move_insertable.
(vector::_S_do_relocate): New overloaded functions to conditionally
call __relocate_a.
(vector::_S_relocate): New function that dispatches to _S_do_relocate
based on _S_use_relocate.
* include/bits/vector.tcc (vector::reserve, vector::_M_realloc_insert)
(vector::_M_default_append): Call _S_relocate instead of __relocate_a.
* testsuite/23_containers/vector/modifiers/push_back/89130.cc: New.
diff --git a/libstdc++-v3/include/bits/alloc_traits.h
b/libstdc++-v3/include/bits/alloc_traits.h
index ed61ce845f8..3b0c16fbf64 100644
--- a/libstdc++-v3/include/bits/alloc_traits.h
+++ b/libstdc++-v3/include/bits/alloc_traits.h
@@ -577,14 +577,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
template<typename _Alloc>
- class __is_copy_insertable_impl
+ class __is_alloc_insertable_impl
{
- typedef allocator_traits<_Alloc> _Traits;
+ using _Traits = allocator_traits<_Alloc>;
+ using value_type = typename _Traits::value_type;
- template<typename _Up, typename
+ template<typename _Up, typename _Tp = __remove_cvref_t<_Up>,
+ typename
= decltype(_Traits::construct(std::declval<_Alloc&>(),
- std::declval<_Up*>(),
- std::declval<const _Up&>()))>
+ std::declval<_Tp*>(),
+ std::declval<_Up>()))>
static true_type
_M_select(int);
@@ -593,13 +595,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_select(...);
public:
- typedef decltype(_M_select<typename _Alloc::value_type>(0)) type;
+ using copy = decltype(_M_select<const value_type&>(0));
+ using move = decltype(_M_select<value_type>(0));
This caused another regression, fixed by the attached patch.
That patch doesn't work with Clang because I made the members
protected and forgot to make them public again (and GCC doesn't cre,
only Clang notices).
Tested powerpc64le-linux, committed to trunk.
commit 6f46cf624c814ea231490bf69afe970acf493543
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Sun Feb 24 15:32:03 2019 +0000
PR libstdc++/89416 fix accessibility of members
PR libstdc++/89416
* include/bits/alloc_traits.h (__is_alloc_insertable_impl): Make
copy and move members public.
diff --git a/libstdc++-v3/include/bits/alloc_traits.h b/libstdc++-v3/include/bits/alloc_traits.h
index 71892cbfaba..9a3d816c42c 100644
--- a/libstdc++-v3/include/bits/alloc_traits.h
+++ b/libstdc++-v3/include/bits/alloc_traits.h
@@ -590,7 +590,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
static false_type
_M_select(...);
- protected:
+ public:
template<typename _Alloc, typename _Tp = typename _Alloc::value_type>
using copy = decltype(_M_select<_Alloc, const _Tp&>(0));
