From patchwork Mon Oct 4 14:24:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Wakely X-Patchwork-Id: 1536145 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=gcc.gnu.org header.i=@gcc.gnu.org header.a=rsa-sha256 header.s=default header.b=W9XMWAhb; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org (client-ip=2620:52:3:1:0:246e:9693:128c; helo=sourceware.org; envelope-from=gcc-patches-bounces+incoming=patchwork.ozlabs.org@gcc.gnu.org; receiver=) Received: from sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4HNNKR6nTlz9t25 for ; Tue, 5 Oct 2021 01:25:14 +1100 (AEDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 868D33858005 for ; Mon, 4 Oct 2021 14:25:10 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 868D33858005 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1633357510; bh=i31BCTBHVG+CBho3+6ygVNadVqpxETXH5WVzL3PY8fw=; h=Date:To:Subject:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=W9XMWAhblKuMZGDMZb1tTLAkWtPCvAOhVWTMiOb69H5fw5EEa3Yb/Ynhz6RZcO5pI mUWn+dELHq8P2vVctgvOoqxVrvJyCdDhg8E5u+EITiJUlQvTxAZpVTLM9svPTcKmS4 i7wFckGhok3BZBZszYnaC8HHu2D9saSLNoVnBS3g= 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 [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id C80D43858D28 for ; Mon, 4 Oct 2021 14:24:28 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C80D43858D28 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-243-cdHXXIWkNRCarzF4aCQ-kQ-1; Mon, 04 Oct 2021 10:24:27 -0400 X-MC-Unique: cdHXXIWkNRCarzF4aCQ-kQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 293D21007300; Mon, 4 Oct 2021 14:24:26 +0000 (UTC) Received: from localhost (unknown [10.33.36.47]) by smtp.corp.redhat.com (Postfix) with ESMTP id CB04B60BD8; Mon, 4 Oct 2021 14:24:25 +0000 (UTC) Date: Mon, 4 Oct 2021 15:24:24 +0100 To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [committed] libstdc++: Disable std::string{, _view} construction from nullptr (P2166R1) Message-ID: MIME-Version: 1.0 X-Clacks-Overhead: GNU Terry Pratchett X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline X-Spam-Status: No, score=-13.8 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_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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+incoming=patchwork.ozlabs.org@gcc.gnu.org Sender: "Gcc-patches" Implement this C++23 feature. Because construction from a null pointer is undefined, we can implement it for C++11 and up, turning undefined behaviour into a compilation error. libstdc++-v3/ChangeLog: * include/bits/basic_string.h (basic_string(nullptr_t)): Define as deleted. (operator=(nullptr_t)): Likewise. * include/bits/cow_string.h (basic_string(nullptr_t)): Likewise. (operator=(nullptr_t)): Likewise. * include/std/string_view (basic_string_view(nullptr_t)): Likewise. * testsuite/21_strings/basic_string/cons/char/nullptr.cc: New test. * testsuite/21_strings/basic_string_view/cons/char/nonnull.cc: Change dg-warning to dg-error. * testsuite/21_strings/basic_string_view/cons/wchar_t/nonnull.cc: Likewise. Tested powerpc64le-linux. Committed to trunk. commit cf876562c592193732f869e9f96034a42d0fad89 Author: Jonathan Wakely Date: Fri Oct 1 21:27:24 2021 libstdc++: Disable std::string{,_view} construction from nullptr (P2166R1) Implement this C++23 feature. Because construction from a null pointer is undefined, we can implement it for C++11 and up, turning undefined behaviour into a compilation error. libstdc++-v3/ChangeLog: * include/bits/basic_string.h (basic_string(nullptr_t)): Define as deleted. (operator=(nullptr_t)): Likewise. * include/bits/cow_string.h (basic_string(nullptr_t)): Likewise. (operator=(nullptr_t)): Likewise. * include/std/string_view (basic_string_view(nullptr_t)): Likewise. * testsuite/21_strings/basic_string/cons/char/nullptr.cc: New test. * testsuite/21_strings/basic_string_view/cons/char/nonnull.cc: Change dg-warning to dg-error. * testsuite/21_strings/basic_string_view/cons/wchar_t/nonnull.cc: Likewise. diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h index 24c454d863a..68c388408f0 100644 --- a/libstdc++-v3/include/bits/basic_string.h +++ b/libstdc++-v3/include/bits/basic_string.h @@ -623,6 +623,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11 _M_construct(__str.begin(), __str.end()); } + basic_string(nullptr_t) = delete; + basic_string& operator=(nullptr_t) = delete; #endif // C++11 /** diff --git a/libstdc++-v3/include/bits/cow_string.h b/libstdc++-v3/include/bits/cow_string.h index ba4a8cc2e98..f0540128364 100644 --- a/libstdc++-v3/include/bits/cow_string.h +++ b/libstdc++-v3/include/bits/cow_string.h @@ -667,6 +667,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION else _M_dataplus._M_p = _S_construct(__str.begin(), __str.end(), __a); } + + basic_string(nullptr_t) = delete; + basic_string& operator=(nullptr_t) = delete; #endif // C++11 /** diff --git a/libstdc++-v3/include/std/string_view b/libstdc++-v3/include/std/string_view index d8cbee9bee0..996b03f9346 100644 --- a/libstdc++-v3/include/std/string_view +++ b/libstdc++-v3/include/std/string_view @@ -168,6 +168,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION #endif // C++23 #endif // C++20 + basic_string_view(nullptr_t) = delete; + constexpr basic_string_view& operator=(const basic_string_view&) noexcept = default; diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/nullptr.cc b/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/nullptr.cc new file mode 100644 index 00000000000..fdb24aeeb89 --- /dev/null +++ b/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/nullptr.cc @@ -0,0 +1,4 @@ +// { dg-do compile { target c++11 } } +#include + +std::string s = nullptr; // { dg-error "deleted" "P2166R1" } diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/char/nonnull.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/char/nonnull.cc index b33af088a3d..f42f95e2fdd 100644 --- a/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/char/nonnull.cc +++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/char/nonnull.cc @@ -25,5 +25,5 @@ test01() { std::string_view s((const char*)nullptr); // { dg-warning "\\\[-Wnonnull" } std::string_view t((char*)nullptr); // { dg-warning "\\\[-Wnonnull" } - std::string_view u(nullptr); // { dg-warning "\\\[-Wnonnull" } + std::string_view u(nullptr); // { dg-error "deleted" } } diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/wchar_t/nonnull.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/wchar_t/nonnull.cc index 4c1013177eb..e480f7c4923 100644 --- a/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/wchar_t/nonnull.cc +++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/wchar_t/nonnull.cc @@ -25,5 +25,5 @@ test01() { std::wstring_view s((const wchar_t*)nullptr); // { dg-warning "\\\[-Wnonnull" } std::wstring_view t((wchar_t*)nullptr); // { dg-warning "\\\[-Wnonnull" } - std::wstring_view u(nullptr); // { dg-warning "\\\[-Wnonnull" } + std::wstring_view u(nullptr); // { dg-error "deleted" } }