From 24fe8c8e338e1c820d942b9c7b997a37705eb29e Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Fri, 3 Apr 2020 10:42:20 +0100 Subject: [PATCH] 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. 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. --- libstdc++-v3/ChangeLog | 8 +++++ libstdc++-v3/include/bits/ptr_traits.h | 11 +++++- .../testsuite/20_util/to_address/1_neg.cc | 2 +- .../testsuite/20_util/to_address/debug.cc | 36 +++++++++++++++++++ 4 files changed, 55 insertions(+), 2 deletions(-) create mode 100644 libstdc++-v3/testsuite/20_util/to_address/debug.cc diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index e713fd235e9..c358977dfbb 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,11 @@ +2020-04-03 Jonathan Wakely + + 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. + 2020-04-01 Andrea Corallo * testsuite/experimental/net/execution_context/use_service.cc: diff --git a/libstdc++-v3/include/bits/ptr_traits.h b/libstdc++-v3/include/bits/ptr_traits.h index 429f7fde520..8fd91bf7bf2 100644 --- a/libstdc++-v3/include/bits/ptr_traits.h +++ b/libstdc++-v3/include/bits/ptr_traits.h @@ -34,6 +34,10 @@ #include +#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 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 ceb2141f10b..ee64a2281fb 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 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 +// . + +// { dg-options "-std=gnu++2a" } +// { dg-do run { target c++2a } } + +#include +#include + +void +test01() +{ + __gnu_debug::vector v{1, 2, 3}; + auto p = std::to_address(v.end()); + VERIFY( p == v.data() + v.size() ); +} + +int +main() +{ + test01(); +} -- 2.30.2