On 26/08/20 19:34 +0100, Jonathan Wakely wrote:
The _Tuple_impl constructor for allocator-extended construction from a
different tuple type uses the _Tuple_impl's own _Head type in the
__use_alloc test. That is incorrect, because the argument tuple could
have a different type. Using the wrong type might select the
leading-allocator convention when it should use the trailing-allocator
convention, or vice versa.
libstdc++-v3/ChangeLog:
PR libstdc++/96803
* include/std/tuple
(_Tuple_impl(allocator_arg_t, Alloc, const _Tuple_impl<U...>&)):
Replace parameter pack with a type parameter and a pack and pass
the first type to __use_alloc.
* testsuite/20_util/tuple/cons/96803.cc: New test.
While backporting 5494edae83ad33c769bd1ebc98f0c492453a6417 I noticed
that it's still not correct. I made the allocator-extended constructor
use the right type for the uses-allocator construction detection, but I
used an rvalue when it should be a const lvalue.
This should fix it properly this time.
libstdc++-v3/ChangeLog:
PR libstdc++/96803
* include/std/tuple
(_Tuple_impl(allocator_arg_t, Alloc, const _Tuple_impl<U...>&)):
Use correct value category in __use_alloc call.
* testsuite/20_util/tuple/cons/96803.cc: Check with constructors
that require correct value category to be used.
Tested powerpc64le-linux. Committed to trunk.
commit 7825399092d572ce8ea82c4aa8dfeb65076b0e52
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Tue Sep 22 08:42:18 2020
libstdc++: Use correct argument type for __use_alloc, again [PR 96803]
While backporting 5494edae83ad33c769bd1ebc98f0c492453a6417 I noticed
that it's still not correct. I made the allocator-extended constructor
use the right type for the uses-allocator construction detection, but I
used an rvalue when it should be a const lvalue.
This should fix it properly this time.
libstdc++-v3/ChangeLog:
PR libstdc++/96803
* include/std/tuple
(_Tuple_impl(allocator_arg_t, Alloc, const _Tuple_impl<U...>&)):
Use correct value category in __use_alloc call.
* testsuite/20_util/tuple/cons/96803.cc: Check with constructors
that require correct value category to be used.
diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple
index 06f56337ce4..11ad1991108 100644
--- a/libstdc++-v3/include/std/tuple
+++ b/libstdc++-v3/include/std/tuple
@@ -355,7 +355,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const _Tuple_impl<_Idx, _UHead, _UTails...>& __in)
: _Inherited(__tag, __a,
_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in)),
- _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
+ _Base(__use_alloc<_Head, _Alloc, const _UHead&>(__a),
_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in))
{ }
diff --git a/libstdc++-v3/testsuite/20_util/tuple/cons/96803.cc b/libstdc++-v3/testsuite/20_util/tuple/cons/96803.cc
index 9d3c07d55b2..867a42150e0 100644
--- a/libstdc++-v3/testsuite/20_util/tuple/cons/96803.cc
+++ b/libstdc++-v3/testsuite/20_util/tuple/cons/96803.cc
@@ -38,4 +38,25 @@ test01()
// std::tuple chooses wrong constructor for uses-allocator construction
std::tuple<int> o;
std::tuple<X> nok(std::allocator_arg, std::allocator<int>(), o);
+
+ std::tuple<int, int> oo;
+ std::tuple<X, X> nn(std::allocator_arg, std::allocator<int>(), oo);
+}
+
+struct Y
+{
+ using allocator_type = std::allocator<int>;
+
+ Y(const X&) { }
+ Y(const X&, const allocator_type&) { }
+
+ Y(X&&) { }
+ Y(std::allocator_arg_t, const allocator_type&, X&&) { }
+};
+
+void
+test02()
+{
+ std::tuple<X, X> o{1, 1};
+ std::tuple<Y, Y> oo(std::allocator_arg, std::allocator<int>(), o);
}
