From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 70DA03858D28 for ; Fri, 22 Mar 2024 22:50:43 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 70DA03858D28 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 70DA03858D28 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1711147846; cv=none; b=siuTt1koldEVJLV3CmMWVAN5RLJ5BN3OtoTCuaE2cMkfdpBDf/P7RmvcFElEWe432WcZv4pNttKLd7zSex3Y8n30OocTd5cifT3ANS6K2Z81BTvfbGh4QL6JQXkEM47h/p8wTQ/fG/tkCIbTJ5ZzJNkrQPZGpnbYo5D31jTcjeo= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1711147846; c=relaxed/simple; bh=FbROVAXhvRgQ6GW9Ul6WPiyvOzgL0wai5i3oyIxYVkU=; h=DKIM-Signature:MIME-Version:From:Date:Message-ID:Subject:To; b=OMvESQVa7WPoCi4DHlUYNiIxzojBFZuaHIeVNIl5J5fy8eB2aC/8s81ZluhugL9Erl5mDdD45Bdfl+47qGDSQ2HpmnHbceUq+YvdxuBDUvNNjlLt9mP79Gfh3n4OzgHA6ttx7tOqqQDZ13RILAIpeFoINOcnBgDBXwSJ8+aPB2g= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1711147843; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gBQ/UVrJpn5Xr9mT3SkcES7H2u/FQeG0YekKEZffKqw=; b=Uz3VF5XWmqRLkNMeVvRRrMa0WahWZDJl2dWxdRQGkPE8xAsHV/07DxjuO8/Topldkb50AN hUmpyH7xdDajJpSCH8Ws06Zx8W2zBKcI9Ty4yNl9i8wwJnCRyzAgLzftNSOizkzobklhiz say3SE+IGFHOvzCX8lu3Gx7bnhSfy5k= Received: from mail-yw1-f199.google.com (mail-yw1-f199.google.com [209.85.128.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-536-PGUKAKDHPy2Eg-YmbF2aRA-1; Fri, 22 Mar 2024 18:50:41 -0400 X-MC-Unique: PGUKAKDHPy2Eg-YmbF2aRA-1 Received: by mail-yw1-f199.google.com with SMTP id 00721157ae682-60ab69a9e6fso47161957b3.0 for ; Fri, 22 Mar 2024 15:50:41 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1711147841; x=1711752641; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=gBQ/UVrJpn5Xr9mT3SkcES7H2u/FQeG0YekKEZffKqw=; b=sOV83nMFCr3c8WTKLtlXPEIrI/BJi+x/XCktx834HDnBiUsDXGuw4Zsl1OE7Zc6t2o PCZfoBJAqERC/rE6AIuxAyA/u7oVPmqZbHfxqJQ5raRYCnUCo6Bsmv6KJ9bHzQRtoFlf MUhePGFD2U9a7hc/Jt6aqDMTpnx3pbqSCI1QxiypCo9uYxJDjIu1fyEavGJjRNNDCMTp uMBDJ1LvTdks2j3oAZVVwAsu2xREHnTgS2gH+8QlyEQtt9k9p5GaZp1u9eiHiuX20pr1 BSXrwpvZElUQgMXGKxDOYpqA1ITb+VeVjbeDPGm921wUyu0heh2bgLgZUDuLGp/WJxSQ 69rw== X-Gm-Message-State: AOJu0YzpQzf/4sJnfr2zQBvQk27n9hKu5ttxrmHP4UfZ46o0XPGWdj1t OtPJk1qV/XZlC0P+Ejf0BfQwesfyhaiwFRcKC5M1NTkHR40PecpCn7KNh6ebf16X/7gsex6pzDo Sr0m3ErifEuMfgECMpOEQ/5yqeGrt3N4yEm3KmXlDWa2adlrUyO/oN2RO/auYSBYqMJMceTqRqz shy6ekh7S72T7ErKNZCQknAuFR4CjULEHHHhE= X-Received: by 2002:a25:3182:0:b0:dc6:c670:c957 with SMTP id x124-20020a253182000000b00dc6c670c957mr168306ybx.32.1711147840985; Fri, 22 Mar 2024 15:50:40 -0700 (PDT) X-Google-Smtp-Source: AGHT+IH1AuGKfgxEI6bf0yn+IJXzJbuIsuB8eEgLowTgdPLGMQzB1LHBEwXV/NlHzKNNjK0pzxwqbRoxSwPKlQOvaUE= X-Received: by 2002:a25:3182:0:b0:dc6:c670:c957 with SMTP id x124-20020a253182000000b00dc6c670c957mr168302ybx.32.1711147840648; Fri, 22 Mar 2024 15:50:40 -0700 (PDT) MIME-Version: 1.0 References: <20240319155858.3406992-1-jwakely@redhat.com> In-Reply-To: <20240319155858.3406992-1-jwakely@redhat.com> From: Jonathan Wakely Date: Fri, 22 Mar 2024 22:50:24 +0000 Message-ID: Subject: Re: [PATCH] libstdc++: Constrain std::vector default constructor [PR113841] To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-12.5 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_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP,URI_HEX autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Pushed to trunk. Backport to gcc-13 needed too, as the changes to use concepts for std::pair constructors are on that branch. On Tue, 19 Mar 2024 at 15:59, Jonathan Wakely wrote: > > This fixes the problem in the PR, which is revealed by the new > concept-based constraints on std::pair constructors in C++20 mode. That > makes this a C++20 regression, as the PR's example compiles with C++17. > > We need something similar for std::basic_string too, which I'll do > later. > > Any comments? > > Tested aarch64-linux. > > -- >8 -- > > This is needed to avoid errors outside the immediate context when > evaluating is_default_constructible_v> when A is not > default constructible. > > To avoid diagnostic regressions for 23_containers/vector/48101_neg.cc we > need to make the std::allocator partial specializations default > constructible, which they probably should have been anyway. > > libstdc++-v3/ChangeLog: > > PR libstdc++/113841 > * include/bits/allocator.h (allocator): Add default > constructor to partial specializations for cv-qualified types. > * include/bits/stl_vector.h (_Vector_impl::_Vector_impl()): > Constrain so that it's only present if the allocator is default > constructible. > * include/bits/stl_bvector.h (_Bvector_impl::_Bvector_impl()): > Likewise. > * testsuite/23_containers/vector/cons/113841.cc: New test. > --- > libstdc++-v3/include/bits/allocator.h | 3 ++ > libstdc++-v3/include/bits/stl_bvector.h | 3 ++ > libstdc++-v3/include/bits/stl_vector.h | 3 ++ > .../23_containers/vector/cons/113841.cc | 34 +++++++++++++++++++ > 4 files changed, 43 insertions(+) > create mode 100644 libstdc++-v3/testsuite/23_containers/vector/cons/113841.cc > > diff --git a/libstdc++-v3/include/bits/allocator.h b/libstdc++-v3/include/bits/allocator.h > index ff4f5b9137b..9e75b37fce7 100644 > --- a/libstdc++-v3/include/bits/allocator.h > +++ b/libstdc++-v3/include/bits/allocator.h > @@ -254,6 +254,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > { > public: > typedef _Tp value_type; > + allocator() { } > template allocator(const allocator<_Up>&) { } > }; > > @@ -262,6 +263,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > { > public: > typedef _Tp value_type; > + allocator() { } > template allocator(const allocator<_Up>&) { } > }; > > @@ -270,6 +272,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > { > public: > typedef _Tp value_type; > + allocator() { } > template allocator(const allocator<_Up>&) { } > }; > /// @endcond > diff --git a/libstdc++-v3/include/bits/stl_bvector.h b/libstdc++-v3/include/bits/stl_bvector.h > index a3343d95b36..d567e26f4e4 100644 > --- a/libstdc++-v3/include/bits/stl_bvector.h > +++ b/libstdc++-v3/include/bits/stl_bvector.h > @@ -593,6 +593,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER > _GLIBCXX20_CONSTEXPR > _Bvector_impl() _GLIBCXX_NOEXCEPT_IF( > is_nothrow_default_constructible<_Bit_alloc_type>::value) > +#if __cpp_concepts > + requires is_default_constructible_v<_Bit_alloc_type> > +#endif > : _Bit_alloc_type() > { } > > diff --git a/libstdc++-v3/include/bits/stl_vector.h b/libstdc++-v3/include/bits/stl_vector.h > index a8d387f40a1..31169711a48 100644 > --- a/libstdc++-v3/include/bits/stl_vector.h > +++ b/libstdc++-v3/include/bits/stl_vector.h > @@ -135,6 +135,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER > _GLIBCXX20_CONSTEXPR > _Vector_impl() _GLIBCXX_NOEXCEPT_IF( > is_nothrow_default_constructible<_Tp_alloc_type>::value) > +#if __cpp_lib_concepts > + requires is_default_constructible_v<_Tp_alloc_type> > +#endif > : _Tp_alloc_type() > { } > > diff --git a/libstdc++-v3/testsuite/23_containers/vector/cons/113841.cc b/libstdc++-v3/testsuite/23_containers/vector/cons/113841.cc > new file mode 100644 > index 00000000000..a7721d27f79 > --- /dev/null > +++ b/libstdc++-v3/testsuite/23_containers/vector/cons/113841.cc > @@ -0,0 +1,34 @@ > +// { dg-do compile { target c++20 } } > + > +#include > + > +template > +struct Alloc > +{ > + using value_type = T; > + > + Alloc(int) { } // not default constructible > + > + template Alloc(const Alloc&) { } > + > + T* allocate(std::size_t n) { return std::allocator().allocate(n); } > + void deallocate(T* p, std::size_t n) { std::allocator().deallocate(p, n); } > +}; > + > +template struct wrap { T t; }; > + > +template void do_adl(T&) { } > + > +void test_pr113841() > +{ > + using test_type = std::vector>; > + std::pair>* h = nullptr; > + do_adl(h); > +} > + > +void test_pr113841_bool() > +{ > + using test_type = std::vector>; > + std::pair>* h = nullptr; > + do_adl(h); > +} > -- > 2.44.0 >