From patchwork Fri Mar 31 14:49:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Wakely X-Patchwork-Id: 67154 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id EC7FF38582AC for ; Fri, 31 Mar 2023 14:50:17 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org EC7FF38582AC DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1680274218; bh=k3hHyad2Auq7G41l1eBL4MIuJ9l/b1Bv4EYOUKbKmg4=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=SjujsT9YH11kwEEEnqihVrCly55U1L2UZjjfDuSGhxu6qmdV3AkoUaiEadki947PR kH/p48PcKj2t7KoOaJmHyHE/i3Z0cqoHX9R7DGsAEE/7q1u3A+tSTCSY6Zs1PWJt7B HbsnzRS1xCN3Ofqt247us0QkLxbecnusWkFtwqPs= X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 3C9063858C53 for ; Fri, 31 Mar 2023 14:49:14 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 3C9063858C53 Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-659-dO41Ock8OW2A6BjKcVbZMg-1; Fri, 31 Mar 2023 10:49:10 -0400 X-MC-Unique: dO41Ock8OW2A6BjKcVbZMg-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 46FA28028B3; Fri, 31 Mar 2023 14:49:10 +0000 (UTC) Received: from localhost (unknown [10.33.36.223]) by smtp.corp.redhat.com (Postfix) with ESMTP id 10BAE492C3E; Fri, 31 Mar 2023 14:49:09 +0000 (UTC) To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [committed] libstdc++: Revert addition of boolean flag to net::ip::basic_endpoint Date: Fri, 31 Mar 2023 15:49:09 +0100 Message-Id: <20230331144909.29872-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-11.8 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Jonathan Wakely via Gcc-patches From: Jonathan Wakely Reply-To: Jonathan Wakely Errors-To: gcc-patches-bounces+patchwork=sourceware.org@gcc.gnu.org Sender: "Gcc-patches" Tested powerpc64le-linux. Pushed to trunk. -- >8 -- As pointed out in P2641R1, we can use GCC's __builtin_constant_p to emulate the proposed std::is_active_member. This allows us to detect which of the union members is active during constant evaluation, so we don't need the extra bool data member. We still can't support constexpr until C++20 though, as we need to change the active member during constant evaluation. libstdc++-v3/ChangeLog: * include/experimental/internet (ip::basic_endpoint::_M_if_v6): Revert change from member function to data member. Fix for constant evaluation by detecting which union member is active. (ip::basic_endpoint::resize): Revert changes to update _M_is_v6 flag. --- libstdc++-v3/include/experimental/internet | 32 ++++++++++------------ 1 file changed, 14 insertions(+), 18 deletions(-) diff --git a/libstdc++-v3/include/experimental/internet b/libstdc++-v3/include/experimental/internet index dff81b456ab..eb23ae21cdc 100644 --- a/libstdc++-v3/include/experimental/internet +++ b/libstdc++-v3/include/experimental/internet @@ -1531,7 +1531,6 @@ namespace ip std::_Construct(&_M_data._M_v6); _M_data._M_v6.sin6_family = __proto.family(); _M_data._M_v6.sin6_port = address_v4::_S_hton_16(__port_num); - _M_is_v6 = true; } else { @@ -1560,7 +1559,6 @@ namespace ip for (int __i = 0; __i < 16; ++__i) __s6a[__i] = __addr._M_v6._M_bytes[__i]; _M_data._M_v6.sin6_scope_id = __addr._M_v6._M_scope_id; - _M_is_v6 = true; } } @@ -1568,13 +1566,13 @@ namespace ip constexpr protocol_type protocol() const noexcept { - return _M_is_v6 ? protocol_type::v6() : protocol_type::v4(); + return _M_is_v6() ? protocol_type::v6() : protocol_type::v4(); } constexpr ip::address address() const noexcept { - if (_M_is_v6) + if (_M_is_v6()) { address_v6 __v6; const uint8_t* __s6a = _M_data._M_v6.sin6_addr.s6_addr; @@ -1601,14 +1599,12 @@ namespace ip __builtin_memcpy(_M_data._M_v6.sin6_addr.s6_addr, __addr._M_v6._M_bytes.data(), 16); _M_data._M_v6.sin6_scope_id = __addr._M_v6._M_scope_id; - _M_is_v6 = true; } else { std::_Construct(&_M_data._M_v4); _M_data._M_v4.sin_family = protocol_type::v4().family(); _M_data._M_v4.sin_addr.s_addr = __addr._M_v4._M_addr; - _M_is_v6 = false; } } @@ -1616,7 +1612,7 @@ namespace ip port() const noexcept { port_type __p = 0; - if (_M_is_v6) + if (_M_is_v6()) __p = _M_data._M_v6.sin6_port; else __p = _M_data._M_v4.sin_port; @@ -1627,7 +1623,7 @@ namespace ip port(port_type __port_num) noexcept { __port_num = address_v4::_S_hton_16(__port_num); - if (_M_is_v6) + if (_M_is_v6()) _M_data._M_v6.sin6_port = __port_num; else _M_data._M_v4.sin_port = __port_num; @@ -1639,19 +1635,11 @@ namespace ip constexpr size_t size() const noexcept - { return _M_is_v6 ? sizeof(sockaddr_in6) : sizeof(sockaddr_in); } + { return _M_is_v6() ? sizeof(sockaddr_in6) : sizeof(sockaddr_in); } void resize(size_t __s) { - __glibcxx_assert(__s >= 0); - static_assert(offsetof(sockaddr_in6, sin6_family) - == offsetof(sockaddr_in, sin_family), - "sockaddr_in::sin_family and sockaddr_in6::sin6_family " - "must be at the same offset"); - const sa_family_t __in6 = AF_INET6; - const auto* __ptr = (char*)&_M_data + offsetof(sockaddr_in, sin_family); - _M_is_v6 = __builtin_memcmp(&__in6, __ptr, sizeof(__in6)) == 0; if (__s != size()) __throw_length_error("net::ip::basic_endpoint::resize"); } @@ -1665,7 +1653,15 @@ namespace ip sockaddr_in6 _M_v6; } _M_data; - bool _M_is_v6 = false; + constexpr bool + _M_is_v6() const noexcept + { + // For constexpr eval we can just detect which union member is active. + // i.e. emulate P2641R1's std::is_active_member(&_M_data._M_v6)). + if (std::__is_constant_evaluated()) + return __builtin_constant_p(_M_data._M_v6.sin6_family); + return _M_data._M_v6.sin6_family == AF_INET6; + } }; /** basic_endpoint comparisons