From patchwork Thu Jun 30 16:53:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Wakely X-Patchwork-Id: 1650827 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=NMpsCWeJ; 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 (2048 bits) server-digest SHA256) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4LYktt5yCKz9s09 for ; Fri, 1 Jul 2022 02:53:57 +1000 (AEST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 8EAF33841897 for ; Thu, 30 Jun 2022 16:53:49 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8EAF33841897 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1656608029; bh=GJ82ZGev9sPRPDC2I4ZIqrx4pwyCU8iUks/TKSRNRCA=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=NMpsCWeJsAXA6TvrNMD0rybnmhhk1jPNklsn2dKJ/4qaidWhgV8UPYbts+p7zreeT bpy6tJHhX4gOsRrw+Sv8sAZRsFacL5F64dToHwx0oNSCe6c6M6hmKGLxQob9R9nIqj MfV6MGYWahIvhusynE12teEMKjYbHWuSUKP35r6s= 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 [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 62D373857367 for ; Thu, 30 Jun 2022 16:53:29 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 62D373857367 Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-526-g6XzMOvKOhekUi0MC0hYow-1; Thu, 30 Jun 2022 12:53:28 -0400 X-MC-Unique: g6XzMOvKOhekUi0MC0hYow-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 631AF3C025D2 for ; Thu, 30 Jun 2022 16:53:27 +0000 (UTC) Received: from localhost (unknown [10.33.36.212]) by smtp.corp.redhat.com (Postfix) with ESMTP id 293D540E6A41; Thu, 30 Jun 2022 16:53:27 +0000 (UTC) To: gcc-patches@gcc.gnu.org Subject: [PATCH] c++: Refer to internal linkage for -Wsubobject-linkage [PR86491] Date: Thu, 30 Jun 2022 17:53:26 +0100 Message-Id: <20220630165326.1253733-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.7 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, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham 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+incoming=patchwork.ozlabs.org@gcc.gnu.org Sender: "Gcc-patches" Tested powerpc64le-linux, OK for trunk? -- >8 -- Since C++11 relaxed the requirement for template arguments to have external linkage, it's possible to get -Wsubobject-linkage warnings without using any anonymous namespaces. This confuses users when they get diagnostics that refer to an anonymous namespace that doesn't exist in their code. This changes the diagnostic to say "has internal linkage" for C++11 and later, which is accurate whether internal linkage is due to the 'static' specifier, or due to the use of anonymous namespaces. For C++98 template arguments declared with 'static' are ill-formed anyway, so the only way this warning can arise is via anonymous namespaces. That means the existing wording is accurate for C++98 and so we can keep it. PR c++/86491 gcc/cp/ChangeLog: * decl2.cc (constrain_class_visibility): Adjust wording of -Wsubobject-linkage to account for cases where anonymous namespaces aren't used. gcc/testsuite/ChangeLog: * g++.dg/warn/Wsubobject-linkage-3.C: Adjust for new warning. * g++.dg/warn/anonymous-namespace-1.C: Use separate dg-warning directives for C++98 and everything else. * g++.dg/warn/anonymous-namespace-2.C: Likewise. * g++.dg/warn/anonymous-namespace-3.C: Likewise. --- gcc/cp/decl2.cc | 12 ++++++++++-- gcc/testsuite/g++.dg/warn/Wsubobject-linkage-3.C | 4 ++-- gcc/testsuite/g++.dg/warn/anonymous-namespace-1.C | 8 ++++++-- gcc/testsuite/g++.dg/warn/anonymous-namespace-2.C | 9 ++++++--- gcc/testsuite/g++.dg/warn/anonymous-namespace-3.C | 3 ++- 5 files changed, 26 insertions(+), 10 deletions(-) diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc index 3737e5f010c..de53678715e 100644 --- a/gcc/cp/decl2.cc +++ b/gcc/cp/decl2.cc @@ -3027,7 +3027,11 @@ constrain_class_visibility (tree type) %qT has a field %qD whose type depends on the type %qT which has no linkage", type, t, nlt); } - else + else if (cxx_dialect > cxx98) + warning (OPT_Wsubobject_linkage, "\ +%qT has a field %qD whose type has internal linkage", + type, t); + else // In C++98 this can only happen with unnamed namespaces. warning (OPT_Wsubobject_linkage, "\ %qT has a field %qD whose type uses the anonymous namespace", type, t); @@ -3062,7 +3066,11 @@ constrain_class_visibility (tree type) %qT has a base %qT whose type depends on the type %qT which has no linkage", type, TREE_TYPE (t), nlt); } - else + else if (cxx_dialect > cxx98) + warning (OPT_Wsubobject_linkage, "\ +%qT has a base %qT whose type has internal linkage", + type, TREE_TYPE (t)); + else // In C++98 this can only happen with unnamed namespaces. warning (OPT_Wsubobject_linkage, "\ %qT has a base %qT whose type uses the anonymous namespace", type, TREE_TYPE (t)); diff --git a/gcc/testsuite/g++.dg/warn/Wsubobject-linkage-3.C b/gcc/testsuite/g++.dg/warn/Wsubobject-linkage-3.C index 95a04501441..b116fbbb186 100644 --- a/gcc/testsuite/g++.dg/warn/Wsubobject-linkage-3.C +++ b/gcc/testsuite/g++.dg/warn/Wsubobject-linkage-3.C @@ -3,7 +3,7 @@ namespace { struct Foo { }; } #line 6 "foo.C" -struct Bar { Foo foo; }; // { dg-warning "anonymous namespace" } +struct Bar { Foo foo; }; // { dg-warning "anonymous namespace|internal linkage" } // { dg-bogus "no linkage" "" { target *-*-* } .-1 } -struct Bar2 : Foo { }; // { dg-warning "anonymous namespace" } +struct Bar2 : Foo { }; // { dg-warning "anonymous namespace|internal linkage" } // { dg-bogus "no linkage" "" { target *-*-* } .-1 } diff --git a/gcc/testsuite/g++.dg/warn/anonymous-namespace-1.C b/gcc/testsuite/g++.dg/warn/anonymous-namespace-1.C index cf193e0cba5..eed3818c5cf 100644 --- a/gcc/testsuite/g++.dg/warn/anonymous-namespace-1.C +++ b/gcc/testsuite/g++.dg/warn/anonymous-namespace-1.C @@ -14,5 +14,9 @@ class foobar1 }; #line 17 "foo.C" -class foobar : public bad { }; // { dg-warning "uses the anonymous namespace" } -class foobar2 { bad b; }; // { dg-warning "uses the anonymous namespace" } +class foobar : public bad { }; +// { dg-warning "has internal linkage" "" { target c++11 } .-1 } +// { dg-warning "uses the anonymous namespace" "" { target c++98_only } .-2 } +class foobar2 { bad b; }; +// { dg-warning "has internal linkage" "" { target c++11 } .-1 } +// { dg-warning "uses the anonymous namespace" "" { target c++98_only } .-2 } diff --git a/gcc/testsuite/g++.dg/warn/anonymous-namespace-2.C b/gcc/testsuite/g++.dg/warn/anonymous-namespace-2.C index 4048f3959df..f2ca5915278 100644 --- a/gcc/testsuite/g++.dg/warn/anonymous-namespace-2.C +++ b/gcc/testsuite/g++.dg/warn/anonymous-namespace-2.C @@ -18,12 +18,15 @@ struct g3 { }; #line 21 "foo.C" -struct b1 { // { dg-warning "uses the anonymous namespace" } +struct b1 { // { dg-warning "has internal linkage" "" { target c++11 } } +// { dg-warning "uses the anonymous namespace" "" { target c++98_only } .-1 } bad * B; }; -struct b2 { // { dg-warning "uses the anonymous namespace" } +struct b2 { // { dg-warning "has internal linkage" "" { target c++11 } } +// { dg-warning "uses the anonymous namespace" "" { target c++98_only } .-1 } bad * B[1]; }; -struct b3 { // { dg-warning "uses the anonymous namespace" } +struct b3 { // { dg-warning "has internal linkage" "" { target c++11 } } +// { dg-warning "uses the anonymous namespace" "" { target c++98_only } .-1 } bad (*B)[1]; }; diff --git a/gcc/testsuite/g++.dg/warn/anonymous-namespace-3.C b/gcc/testsuite/g++.dg/warn/anonymous-namespace-3.C index 8b72abdf5d1..ce5745b25f0 100644 --- a/gcc/testsuite/g++.dg/warn/anonymous-namespace-3.C +++ b/gcc/testsuite/g++.dg/warn/anonymous-namespace-3.C @@ -7,7 +7,8 @@ struct B { std::auto_ptr p; }; #line 10 "foo.C" -struct C // { dg-warning "uses the anonymous namespace" } +struct C // { dg-warning "has internal linkage" "" { target c++11 } } +// { dg-warning "uses the anonymous namespace" "" { target c++98_only } .-1 } { std::auto_ptr p; };