From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id BE5DB3850429; Mon, 29 Mar 2021 20:03:31 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org BE5DB3850429 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jonathan Wakely To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r10-9595] libstdc++: Add noexcept to std::begin etc as per LWG 2280 and 3537 X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/releases/gcc-10 X-Git-Oldrev: ad9ae82ed1c33e1803f33bb367b0b4c9ee2e3e63 X-Git-Newrev: e7b2f969346435c5b460a4021b1334c0a4c11df2 Message-Id: <20210329200331.BE5DB3850429@sourceware.org> Date: Mon, 29 Mar 2021 20:03:31 +0000 (GMT) X-BeenThere: libstdc++-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 29 Mar 2021 20:03:31 -0000 https://gcc.gnu.org/g:e7b2f969346435c5b460a4021b1334c0a4c11df2 commit r10-9595-ge7b2f969346435c5b460a4021b1334c0a4c11df2 Author: Jonathan Wakely Date: Mon Mar 22 15:15:12 2021 +0000 libstdc++: Add noexcept to std::begin etc as per LWG 2280 and 3537 This implements the proposed changes for LWG 3537 (which we're allowed to do as an extension whatever the outcome of the issue). I noticed we didn't implement LWG 2280 completely, as the std::begin and std::end overloads for arrays were not noexcept. libstdc++-v3/ChangeLog: * include/bits/range_access.h (begin(T (&)[N]), end(T (&)[N])): Add missing 'noexcept' as per LWG 2280. (rbegin(T (&)[N]), rend(T (&)[N]), rbegin(initializer_list)) (rend(initializer_list)): Add 'noexcept' as per LWG 3537. * testsuite/24_iterators/range_access/range_access.cc: Check for expected noexcept specifiers. Check result types of generic std::begin and std::end overloads. * testsuite/24_iterators/range_access/range_access_cpp14.cc: Check for expected noexcept specifiers. * testsuite/24_iterators/range_access/range_access_cpp17.cc: Likewise. (cherry picked from commit 00b46c00c8d9003c61e8f817668ad3380e16fedb) Diff: --- libstdc++-v3/include/bits/range_access.h | 12 ++++----- .../24_iterators/range_access/range_access.cc | 30 ++++++++++++++++++++++ .../range_access/range_access_cpp14.cc | 15 +++++++++++ .../range_access/range_access_cpp17.cc | 14 ++++++++++ 4 files changed, 65 insertions(+), 6 deletions(-) diff --git a/libstdc++-v3/include/bits/range_access.h b/libstdc++-v3/include/bits/range_access.h index 3853bbf862b..c93d1e37f34 100644 --- a/libstdc++-v3/include/bits/range_access.h +++ b/libstdc++-v3/include/bits/range_access.h @@ -87,7 +87,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION */ template inline _GLIBCXX14_CONSTEXPR _Tp* - begin(_Tp (&__arr)[_Nm]) + begin(_Tp (&__arr)[_Nm]) noexcept { return __arr; } /** @@ -97,7 +97,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION */ template inline _GLIBCXX14_CONSTEXPR _Tp* - end(_Tp (&__arr)[_Nm]) + end(_Tp (&__arr)[_Nm]) noexcept { return __arr + _Nm; } #if __cplusplus >= 201402L @@ -178,7 +178,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION */ template inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Tp*> - rbegin(_Tp (&__arr)[_Nm]) + rbegin(_Tp (&__arr)[_Nm]) noexcept { return reverse_iterator<_Tp*>(__arr + _Nm); } /** @@ -188,7 +188,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION */ template inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Tp*> - rend(_Tp (&__arr)[_Nm]) + rend(_Tp (&__arr)[_Nm]) noexcept { return reverse_iterator<_Tp*>(__arr); } /** @@ -198,7 +198,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION */ template inline _GLIBCXX17_CONSTEXPR reverse_iterator - rbegin(initializer_list<_Tp> __il) + rbegin(initializer_list<_Tp> __il) noexcept { return reverse_iterator(__il.end()); } /** @@ -208,7 +208,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION */ template inline _GLIBCXX17_CONSTEXPR reverse_iterator - rend(initializer_list<_Tp> __il) + rend(initializer_list<_Tp> __il) noexcept { return reverse_iterator(__il.begin()); } /** diff --git a/libstdc++-v3/testsuite/24_iterators/range_access/range_access.cc b/libstdc++-v3/testsuite/24_iterators/range_access/range_access.cc index 865e784738c..d86ea3271e2 100644 --- a/libstdc++-v3/testsuite/24_iterators/range_access/range_access.cc +++ b/libstdc++-v3/testsuite/24_iterators/range_access/range_access.cc @@ -27,4 +27,34 @@ test01() int arr[3] = {1, 2, 3}; std::begin(arr); std::end(arr); + + static_assert( noexcept(std::begin(arr)), "LWG 2280" ); + static_assert( noexcept(std::end(arr)), "LWG 2280" ); +} + +void +test02() +{ + extern void require_int(int*); + extern void require_long(long*); + + struct B + { + int* begin() { return nullptr; } + long* begin() const { return nullptr; } + }; + + B b; + require_int( std::begin(b) ); + require_long( std::begin(const_cast(b)) ); + + struct E + { + int* end() { return nullptr; } + long* end() const { return nullptr; } + }; + + E e; + require_int( std::end(e) ); + require_long( std::end(const_cast(e)) ); } diff --git a/libstdc++-v3/testsuite/24_iterators/range_access/range_access_cpp14.cc b/libstdc++-v3/testsuite/24_iterators/range_access/range_access_cpp14.cc index 1df05ba9c5e..e66caf97cbd 100644 --- a/libstdc++-v3/testsuite/24_iterators/range_access/range_access_cpp14.cc +++ b/libstdc++-v3/testsuite/24_iterators/range_access/range_access_cpp14.cc @@ -39,10 +39,21 @@ void test02() { static int i[1]; + // LWG 2280 constexpr auto b __attribute__((unused)) = std::begin(i); constexpr auto e __attribute__((unused)) = std::end(i); constexpr auto cb __attribute__((unused)) = std::cbegin(i); constexpr auto ce __attribute__((unused)) = std::cend(i); + + // LWG 2280 + static_assert( noexcept(std::begin(i)), "LWG 2280" ); + static_assert( noexcept(std::end(i)), "LWG 2280" ); + static_assert( noexcept(std::cbegin(i)), "LWG 2280" ); + static_assert( noexcept(std::cend(i)), "LWG 2280" ); + + // LWG 3537 + static_assert( noexcept(std::rbegin(i)), "LWG 3537" ); + static_assert( noexcept(std::rend(i)), "LWG 3537" ); } void @@ -55,6 +66,10 @@ test03() VERIFY(std::rend(il) == std::reverse_iterator(il.begin())); VERIFY(std::crbegin(il) == std::reverse_iterator(il.end())); VERIFY(std::crend(il) == std::reverse_iterator(il.begin())); + + // LWG 3537 + static_assert( noexcept(std::rbegin(il)), "LWG 3537" ); + static_assert( noexcept(std::rend(il)), "LWG 3537" ); } void diff --git a/libstdc++-v3/testsuite/24_iterators/range_access/range_access_cpp17.cc b/libstdc++-v3/testsuite/24_iterators/range_access/range_access_cpp17.cc index 00a856776f7..fe4da9a6df3 100644 --- a/libstdc++-v3/testsuite/24_iterators/range_access/range_access_cpp17.cc +++ b/libstdc++-v3/testsuite/24_iterators/range_access/range_access_cpp17.cc @@ -41,6 +41,16 @@ test02() static int i[] = { 1, 2 }; static_assert(std::distance(std::begin(i), std::end(i)) == 2); static_assert(std::distance(std::cbegin(i), std::cend(i)) == 2); + + // LWG 2280 + static_assert( noexcept(std::begin(i)), "LWG 2280" ); + static_assert( noexcept(std::end(i)), "LWG 2280" ); + static_assert( noexcept(std::cbegin(i)), "LWG 2280" ); + static_assert( noexcept(std::cend(i)), "LWG 2280" ); + + // LWG 3537 + static_assert( noexcept(std::rbegin(i)), "LWG 3537" ); + static_assert( noexcept(std::rend(i)), "LWG 3537" ); } void @@ -54,4 +64,8 @@ test03() static_assert(std::rend(il) == reverse_iterator(il.begin())); static_assert(std::crbegin(il) == reverse_iterator(il.end())); static_assert(std::crend(il) == reverse_iterator(il.begin())); + + // LWG 3537 + static_assert( noexcept(std::rbegin(il)), "LWG 3537" ); + static_assert( noexcept(std::rend(il)), "LWG 3537" ); }