[gcc(refs/vendors/ibm/heads/gcc-8-branch)] libstdc++: Fix std::to_address for debug iterators (PR 93960)
Peter Bergner
bergner@gcc.gnu.org
Thu Apr 23 18:51:58 GMT 2020
https://gcc.gnu.org/g:afae9879c28a2797c49bf2da51415da70cdd2b83
commit afae9879c28a2797c49bf2da51415da70cdd2b83
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Fri Apr 3 12:00:07 2020 +0100
libstdc++: Fix std::to_address for debug iterators (PR 93960)
It should be valid to use std::to_address on a past-the-end iterator,
but the debug mode iterators do a check for dereferenceable in their
operator->(). That check is generally useful, so rather than remove it
this changes std::__to_address to identify a debug mode iterator and
use base().operator->() to skip the check.
Backport from mainline
2020-04-03 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/93960
* include/bits/ptr_traits.h (__to_address): Add special case for debug
iterators, to avoid dereferenceable check.
* testsuite/20_util/to_address/1_neg.cc: Adjust dg-error line number.
* testsuite/20_util/to_address/debug.cc: New test.
Diff:
---
libstdc++-v3/ChangeLog | 11 +++++++
libstdc++-v3/include/bits/ptr_traits.h | 11 ++++++-
libstdc++-v3/testsuite/20_util/to_address/1_neg.cc | 2 +-
libstdc++-v3/testsuite/20_util/to_address/debug.cc | 36 ++++++++++++++++++++++
4 files changed, 58 insertions(+), 2 deletions(-)
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 1d6f972584a..495f6809729 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,14 @@
+2020-04-03 Jonathan Wakely <jwakely@redhat.com>
+
+ Backport from mainline
+ 2020-04-03 Jonathan Wakely <jwakely@redhat.com>
+
+ PR libstdc++/93960
+ * include/bits/ptr_traits.h (__to_address): Add special case for debug
+ iterators, to avoid dereferenceable check.
+ * testsuite/20_util/to_address/1_neg.cc: Adjust dg-error line number.
+ * testsuite/20_util/to_address/debug.cc: New test.
+
2020-03-04 Release Manager
* GCC 8.4.0 released.
diff --git a/libstdc++-v3/include/bits/ptr_traits.h b/libstdc++-v3/include/bits/ptr_traits.h
index 11b6056370a..88261de02d6 100644
--- a/libstdc++-v3/include/bits/ptr_traits.h
+++ b/libstdc++-v3/include/bits/ptr_traits.h
@@ -34,6 +34,10 @@
#include <bits/move.h>
+#if __cplusplus > 201703L
+namespace __gnu_debug { struct _Safe_iterator_base; }
+#endif
+
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -169,7 +173,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Ptr, typename... _None>
constexpr auto
__to_address(const _Ptr& __ptr, _None...) noexcept
- { return std::__to_address(__ptr.operator->()); }
+ {
+ if constexpr (is_base_of_v<__gnu_debug::_Safe_iterator_base, _Ptr>)
+ return std::__to_address(__ptr.base().operator->());
+ else
+ return std::__to_address(__ptr.operator->());
+ }
/**
* @brief Obtain address referenced by a pointer to an object
diff --git a/libstdc++-v3/testsuite/20_util/to_address/1_neg.cc b/libstdc++-v3/testsuite/20_util/to_address/1_neg.cc
index e5681de588f..3346253f2a8 100644
--- a/libstdc++-v3/testsuite/20_util/to_address/1_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/to_address/1_neg.cc
@@ -17,7 +17,7 @@
// { dg-options "-std=gnu++2a" }
// { dg-do compile { target c++2a } }
-// { dg-error "not a function pointer" "" { target *-*-* } 153 }
+// { dg-error "not a function pointer" "" { target *-*-* } 157 }
#include <memory>
diff --git a/libstdc++-v3/testsuite/20_util/to_address/debug.cc b/libstdc++-v3/testsuite/20_util/to_address/debug.cc
new file mode 100644
index 00000000000..4555284416d
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/to_address/debug.cc
@@ -0,0 +1,36 @@
+// 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-options "-std=gnu++2a" }
+// { dg-do run { target c++2a } }
+
+#include <debug/vector>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+ __gnu_debug::vector<int> v{1, 2, 3};
+ auto p = std::to_address(v.end());
+ VERIFY( p == v.data() + v.size() );
+}
+
+int
+main()
+{
+ test01();
+}
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