libstdc++: Fix regressions in unique_ptr::swap (PR 93562)

The requirements for this function are only that the deleter is
swappable, but we incorrectly require that the element type is complete
and that the deleter can be swapped using std::swap (which requires it
to be move cosntructible and move assignable).

The fix is to add __uniq_ptr_impl::swap which swaps the pointer and
deleter individually, instead of using the generic std::swap on the
tuple containing them.

	PR libstdc++/93562
	* include/bits/unique_ptr.h (__uniq_ptr_impl::swap): Define.
	(unique_ptr::swap, unique_ptr<T[], D>::swap): Call it.
	* testsuite/20_util/unique_ptr/modifiers/93562.cc: New test.

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index a94334f8ab166f30d7c665f474dc11ae08bd7916..075442c124a7a619da566b04fb96ed12840684af 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,13 @@
 2020-02-26  Jonathan Wakely  <jwakely@redhat.com>
 
+       Backport from mainline
+       2020-02-04  Jonathan Wakely  <jwakely@redhat.com>
+
+       PR libstdc++/93562
+       * include/bits/unique_ptr.h (__uniq_ptr_impl::swap): Define.
+       (unique_ptr::swap, unique_ptr<T[], D>::swap): Call it.
+       * testsuite/20_util/unique_ptr/modifiers/93562.cc: New test.
+
        Backport from mainline
        2020-01-17  Jonathan Wakely  <jwakely@redhat.com>
 

diff --git a/libstdc++-v3/include/bits/unique_ptr.h b/libstdc++-v3/include/bits/unique_ptr.h
index d8129747eb5d3c6634c4f6586aaacb58f7022c2f..c934873a72202f59c68b99d8808aafb6cbf00b18 100644 (file)
--- a/libstdc++-v3/include/bits/unique_ptr.h
+++ b/libstdc++-v3/include/bits/unique_ptr.h
@@ -155,6 +155,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _Dp&       _M_deleter() { return std::get<1>(_M_t); }
       const _Dp& _M_deleter() const { return std::get<1>(_M_t); }
 
+      void
+      swap(__uniq_ptr_impl& __rhs) noexcept
+      {
+       using std::swap;
+       swap(this->_M_ptr(), __rhs._M_ptr());
+       swap(this->_M_deleter(), __rhs._M_deleter());
+      }
+
     private:
       tuple<pointer, _Dp> _M_t;
     };
@@ -398,8 +406,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       void
       swap(unique_ptr& __u) noexcept
       {
-       using std::swap;
-       swap(_M_t, __u._M_t);
+       static_assert(__is_swappable<_Dp>::value, "deleter must be swappable");
+       _M_t.swap(__u._M_t);
       }
 
       // Disable copy from lvalue.
@@ -673,8 +681,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       void
       swap(unique_ptr& __u) noexcept
       {
-       using std::swap;
-       swap(_M_t, __u._M_t);
+       static_assert(__is_swappable<_Dp>::value, "deleter must be swappable");
+       _M_t.swap(__u._M_t);
       }
 
       // Disable copy from lvalue.

diff --git a/libstdc++-v3/testsuite/20_util/unique_ptr/modifiers/93562.cc b/libstdc++-v3/testsuite/20_util/unique_ptr/modifiers/93562.cc
new file mode 100644 (file)
index 0000000..8ed2363
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/unique_ptr/modifiers/93562.cc
@@ -0,0 +1,98 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-do run { target c++11 } }
+
+#include <memory>
+#include <testsuite_hooks.h>
+
+struct incomplete;
+
+// This function isn't called, we just need to check it compiles.
+void
+test01(std::unique_ptr<incomplete>& p1, std::unique_ptr<incomplete>& p2)
+{
+  // PR libstdc++/93562
+  p1.swap(p2);
+  swap(p1, p2);
+}
+
+// This function isn't called, we just need to check it compiles.
+void
+test02(std::unique_ptr<incomplete[]>& p1, std::unique_ptr<incomplete[]>& p2)
+{
+  // PR libstdc++/93562
+  p1.swap(p2);
+  swap(p1, p2);
+}
+
+namespace A
+{
+  struct Deleter
+  {
+    Deleter& operator=(const Deleter&) = delete;
+
+    void operator()(int* p) const noexcept { delete p; }
+
+    // found by ADL
+    friend void swap(Deleter& lhs, Deleter& rhs) noexcept
+    { std::swap(lhs.id, rhs.id); }
+
+    int id;
+  };
+
+  static_assert(!std::is_move_assignable<Deleter>::value, "not assignable");
+#if __cplusplus >= 201703L
+  static_assert(std::is_swappable_v<Deleter>, "but swappable");
+#endif
+} // namespace A
+
+void
+test03()
+{
+  std::unique_ptr<int, A::Deleter> p1(new int(1), { -1 });
+  std::unique_ptr<int, A::Deleter> p2(new int(2), { -2 });
+  int* const pi1 = p1.get();
+  int* const pi2 = p2.get();
+  // This type must swappable even though the deleter is not move-assignable:
+  swap(p1, p2);
+  VERIFY(p1.get() == pi2);
+  VERIFY(p1.get_deleter().id == -2);
+  VERIFY(p2.get() == pi1);
+  VERIFY(p2.get_deleter().id == -1);
+}
+
+void
+test04()
+{
+  std::unique_ptr<int[], A::Deleter> p1(new int[1]{1}, { -1 });
+  std::unique_ptr<int[], A::Deleter> p2(new int[2]{2, 2}, { -2 });
+  int* const pi1 = p1.get();
+  int* const pi2 = p2.get();
+  // This type must swappable even though the deleter is not move-assignable:
+  swap(p1, p2);
+  VERIFY(p1.get() == pi2);
+  VERIFY(p1.get_deleter().id == -2);
+  VERIFY(p2.get() == pi1);
+  VERIFY(p2.get_deleter().id == -1);
+}
+
+int main()
+{
+  test03();
+  test04();
+}