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 [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id 160D83870841 for ; Thu, 21 Jan 2021 15:39:44 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 160D83870841 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-477-WamYawfePAmHSuK6_GVPkA-1; Thu, 21 Jan 2021 10:39:41 -0500 X-MC-Unique: WamYawfePAmHSuK6_GVPkA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id F1035107ACE4 for ; Thu, 21 Jan 2021 15:39:40 +0000 (UTC) Received: from redhat.com (ovpn-112-35.rdu2.redhat.com [10.10.112.35]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 884A85D9C6; Thu, 21 Jan 2021 15:39:40 +0000 (UTC) Date: Thu, 21 Jan 2021 10:39:38 -0500 From: Marek Polacek To: Jason Merrill Cc: GCC Patches Subject: Re: [PATCH v3] c++: ICE with delayed noexcept and attribute used [PR97966] Message-ID: <20210121153938.GD3666@redhat.com> References: <20210113021346.98238-1-polacek@redhat.com> <911fa149-69b1-fbb7-60f2-7c8d5246d4cc@redhat.com> <20210121004948.GC3666@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-14.9 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_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) 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-List-Received-Date: Thu, 21 Jan 2021 15:39:45 -0000 On Thu, Jan 21, 2021 at 01:55:24AM -0500, Jason Merrill wrote: > > + /* Now that we've gone through all the members, instantiate those > > + marked with attribute used. */ > > + for (tree &x : used) > > This doesn't need to be a reference. And I think we want this to happen > even later, after finish_struct_1. Fair enough, here's an updated version. Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? -- >8 -- Another ICE with delayed noexcept parsing, but a bit gnarlier. A function definition marked with __attribute__((used)) ought to be emitted even when it is not referenced in the TU. For a member function template marked with __attribute__((used)) this means that it will be instantiated: in instantiate_class_template_1 we have 11971 /* Instantiate members marked with attribute used. */ 11972 if (r != error_mark_node && DECL_PRESERVE_P (r)) 11973 mark_used (r); It is not so surprising that this doesn't work well with delayed noexcept parsing: when we're processing the function template we delay the parsing, so the member "foo" is found, but then when we're instantiating it, "foo" hasn't yet been seen, which creates a discrepancy and a crash ensues. "foo" hasn't yet been seen because instantiate_class_template_1 just loops over the class members and instantiates right away. To make it work, this patch uses a vector to keep track of members marked with attribute used and uses it to instantiate such members only after we're done with the class; in particular, after we have called finish_member_declaration for each member. And we ought to be verifying that we did emit such members, so I've added a bunch of dg-finals. gcc/cp/ChangeLog: PR c++/97966 * pt.c (instantiate_class_template_1): Instantiate members marked with attribute used only after we're done instantiating the class. gcc/testsuite/ChangeLog: PR c++/97966 * g++.dg/cpp0x/noexcept63.C: New test. --- gcc/cp/pt.c | 12 ++++- gcc/testsuite/g++.dg/cpp0x/noexcept63.C | 63 +++++++++++++++++++++++++ 2 files changed, 73 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept63.C diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index 373f8279604..1f3850d1048 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -11895,6 +11895,9 @@ instantiate_class_template_1 (tree type) relative to the scope of the class. */ pop_to_parent_deferring_access_checks (); + /* A vector to hold members marked with attribute used. */ + auto_vec used; + /* Now members are processed in the order of declaration. */ for (member = CLASSTYPE_DECL_LIST (pattern); member; member = TREE_CHAIN (member)) @@ -11968,7 +11971,7 @@ instantiate_class_template_1 (tree type) finish_member_declaration (r); /* Instantiate members marked with attribute used. */ if (r != error_mark_node && DECL_PRESERVE_P (r)) - mark_used (r); + used.safe_push (r); if (TREE_CODE (r) == FUNCTION_DECL && DECL_OMP_DECLARE_REDUCTION_P (r)) cp_check_omp_declare_reduction (r); @@ -12034,7 +12037,7 @@ instantiate_class_template_1 (tree type) /*flags=*/0); /* Instantiate members marked with attribute used. */ if (r != error_mark_node && DECL_PRESERVE_P (r)) - mark_used (r); + used.safe_push (r); } else if (TREE_CODE (r) == FIELD_DECL) { @@ -12203,6 +12206,11 @@ instantiate_class_template_1 (tree type) finish_struct_1 (type); TYPE_BEING_DEFINED (type) = 0; + /* Now that we've gone through all the members, instantiate those + marked with attribute used. */ + for (tree x : used) + mark_used (x); + /* We don't instantiate default arguments for member functions. 14.7.1: The implicit instantiation of a class template specialization causes diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept63.C b/gcc/testsuite/g++.dg/cpp0x/noexcept63.C new file mode 100644 index 00000000000..cf048f56c2a --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept63.C @@ -0,0 +1,63 @@ +// PR c++/97966 +// { dg-do compile { target c++11 } } + +template +struct S1 { + __attribute__((used)) S1() noexcept(noexcept(this->foo())) { } + void foo(); +}; + +template +struct S2 { + __attribute__((used)) void bar() noexcept(noexcept(this->foo())) { } + void foo(); +}; + +template +struct S3 { + void __attribute__((used)) bar() noexcept(noexcept(this->foo())) { } + void foo(); +}; + +template +struct S4 { + [[gnu::used]] void bar() noexcept(noexcept(this->foo())) { } + void foo(); +}; + +template +struct S5 { + void bar() noexcept(noexcept(this->foo())) __attribute__((used)) { } + void foo(); +}; + +template +struct S6 { + template + struct N { + [[gnu::used]] void bar() noexcept(noexcept(this->foo())) { } + void foo(); + }; +}; + +void +g () +{ + S1<1> s1; + S2<1> s2; + S3<1> s3; + S4<1> s4; + S5<1> s5; + S6<1>::N<1> n; +} + +// Make sure that we did emit the functions marked with attribute used +// even though they're not referenced in this TU. (Well, the S1() +// constructor is.) +// { dg-final { scan-assembler "_ZN2S1ILi1EEC1Ev" } } +// { dg-final { scan-assembler "_ZN2S1ILi1EEC2Ev" } } +// { dg-final { scan-assembler "_ZN2S2ILi1EE3barEv" } } +// { dg-final { scan-assembler "_ZN2S3ILi1EE3barEv" } } +// { dg-final { scan-assembler "_ZN2S4ILi1EE3barEv" } } +// { dg-final { scan-assembler "_ZN2S5ILi1EE3barEv" } } +// { dg-final { scan-assembler "_ZN2S6ILi1EE1NILi1EE3barEv" } } base-commit: 43705f3fa343e08b2fb030460fc5e2a969954398 -- 2.29.2