From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 73266 invoked by alias); 7 Dec 2018 00:23:49 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 73252 invoked by uid 89); 7 Dec 2018 00:23:49 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-26.9 required=5.0 tests=BAYES_00,GIT_PATCH_0,GIT_PATCH_1,GIT_PATCH_2,GIT_PATCH_3,SPF_HELO_PASS,TIME_LIMIT_EXCEEDED autolearn=unavailable version=3.3.2 spammy=revealed, cloned, rolled, mistakenly X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 07 Dec 2018 00:23:38 +0000 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A3076307CDD3 for ; Fri, 7 Dec 2018 00:23:37 +0000 (UTC) Received: from free.home (ovpn04.gateway.prod.ext.phx2.redhat.com [10.5.9.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5955E8501; Fri, 7 Dec 2018 00:23:37 +0000 (UTC) Received: from livre (livre.home [172.31.160.2]) by free.home (8.15.2/8.15.2) with ESMTP id wB70NR86089841; Thu, 6 Dec 2018 22:23:27 -0200 From: Alexandre Oliva To: gcc-patches@gcc.gnu.org Subject: [C++ Patch] [PR c++/88146] do not crash synthesizing inherited ctor(...) Date: Fri, 07 Dec 2018 00:23:00 -0000 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-SW-Source: 2018-12/txt/msg00424.txt.bz2 This patch started out from the testcase in PR88146, that attempted to synthesize an inherited ctor without any args before a varargs ellipsis and crashed while at that, because of the unguarded dereferencing of the parm type list, that usually contains a terminator. The terminator is not there for varargs functions, however, and without any other args, we ended up dereferencing a NULL pointer. Oops. Guarding the accesses there was easy, but I missed the sorry message we got in other testcases that passed arguments through the ellipsis in inherited ctors. I put a check in, and noticed the inherited ctors were synthesized with the location assigned to the class name, although they were initially assigned the location of the using declaration. I decided the latter was better, and arranged for the better location to be retained. Further investigation revealed the lack of a sorry message had to do with the call being in a non-evaluated context, in this case, a noexcept expression. The sorry would be correctly reported in other contexts, so I rolled back the check I'd added, but retained the source location improvement. I was still concerned about issuing sorry messages while instantiating template ctors even in non-evaluated contexts, e.g., if a template ctor had a base initializer that used an inherited ctor with enough arguments that they'd go through an ellipsis. I wanted to defer the instantiation of such template ctors, but that would have been wrong for constexpr template ctors, and already done for non-constexpr ones. So, I just consolidated multiple test variants into a single testcase that explores and explains various of the possibilities I thought of. Regstrapped on x86_64- and i686-linux-gnu, mistakenly along with a patch with a known regression, and got only that known regression. Retesting without it. Ok to install? for gcc/cp/ChangeLog PR c++/88146 * method.c (do_build_copy_constructor): Do not crash with ellipsis-only parm list. (synthesize_method): Retain location of inherited ctor. for gcc/testsuite/ChangeLog PR c++/88146 * g++.dg/cpp0x/inh-ctor32.C: New. --- gcc/cp/method.c | 9 + gcc/testsuite/g++.dg/cpp0x/inh-ctor32.C | 229 +++++++++++++++++++++++++++= ++++ 2 files changed, 234 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/inh-ctor32.C diff --git a/gcc/cp/method.c b/gcc/cp/method.c index fd023e200538..41d609fb1de6 100644 --- a/gcc/cp/method.c +++ b/gcc/cp/method.c @@ -643,7 +643,7 @@ do_build_copy_constructor (tree fndecl) bool trivial =3D trivial_fn_p (fndecl); tree inh =3D DECL_INHERITED_CTOR (fndecl); =20 - if (!inh) + if (parm && !inh) parm =3D convert_from_reference (parm); =20 if (trivial) @@ -677,7 +677,7 @@ do_build_copy_constructor (tree fndecl) { tree fields =3D TYPE_FIELDS (current_class_type); tree member_init_list =3D NULL_TREE; - int cvquals =3D cp_type_quals (TREE_TYPE (parm)); + int cvquals =3D parm ? cp_type_quals (TREE_TYPE (parm)) : 0; int i; tree binfo, base_binfo; tree init; @@ -891,8 +891,9 @@ synthesize_method (tree fndecl) =20 /* Reset the source location, we might have been previously deferred, and thus have saved where we were first needed. */ - DECL_SOURCE_LOCATION (fndecl) - =3D DECL_SOURCE_LOCATION (TYPE_NAME (DECL_CONTEXT (fndecl))); + if (!DECL_INHERITED_CTOR (fndecl)) + DECL_SOURCE_LOCATION (fndecl) + =3D DECL_SOURCE_LOCATION (TYPE_NAME (DECL_CONTEXT (fndecl))); =20 /* If we've been asked to synthesize a clone, just synthesize the cloned function instead. Doing so will automatically fill in the diff --git a/gcc/testsuite/g++.dg/cpp0x/inh-ctor32.C b/gcc/testsuite/g++.dg= /cpp0x/inh-ctor32.C new file mode 100644 index 000000000000..c40412fc5346 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/inh-ctor32.C @@ -0,0 +1,229 @@ +// { dg-do compile { target c++11 } } +// Minimized from the testcase for PR c++/88146, +// then turned into multiple variants.=20 + +// We issue an error when calling an inherited ctor with at least one +// argument passed through a varargs ellipsis, if the call is in an +// evaluated context. Even in nonevaluated contexts, we will +// instantiate constexpr templates (unlike non-constexpr templates), +// which might then issue errors that in nonevlauated contexts +// wouldn't be issued. + +// In these variants, the inherited ctor is constexpr, but it's only +// called in unevaluated contexts, so no error is issued. The +// templateness of the ctor doesn't matter, because the only call that +// passes args through the ellipsis is in a noexcept expr, that is not +// evaluated. The ctors in derived classes are created and +// instantiated, discarding arguments passed through the ellipsis when +// calling base ctors, but that's not reported: we only report a +// problem when *calling* ctors that behave this way. +namespace unevaled_call { + namespace no_arg_before_ellipsis { + namespace without_template { + struct foo { + constexpr foo(...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bar : boo { + using boo::boo; + }; + void f() noexcept(noexcept(bar{0})); + } + + namespace with_template { + struct foo { + template + constexpr foo(...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bar : boo { + using boo::boo; + }; + void f() noexcept(noexcept(bar{0})); + } + } + + namespace one_arg_before_ellipsis { + namespace without_template { + struct foo { + constexpr foo(int, ...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bar : boo { + using boo::boo; + }; + void f() noexcept(noexcept(bar{0,1})); + } + + namespace with_template { + struct foo { + template + constexpr foo(T, ...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bar : boo { + using boo::boo; + }; + void f() noexcept(noexcept(bar{0,1})); + } + } +} + +// In these variants, the inherited ctor is constexpr, and it's called +// in unevaluated contexts in ways that would otherwise trigger the +// sorry message. Here we check that the message is not issued at +// those calls, nor at subsequent calls that use the same ctor without +// passing arguments through its ellipsis. We check that it is issued +// later, when we pass the ctor arguments through the ellipsis. +namespace evaled_bad_call_in_u { + namespace one_arg_before_ellipsis { + namespace without_template { + struct foo { + constexpr foo(int, ...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bar : boo { + using boo::boo; + }; + void f() noexcept(noexcept(bar{0, 1})); + bar t(0); + bar u(0, 1); // { dg-message "sorry, unimplemented: passing argument= s to ellipsis" } + } + + namespace with_template { + struct foo { + template + constexpr foo(T, ...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bar : boo { + using boo::boo; + }; + void f() noexcept(noexcept(bar{0,1})); + bar t(0); + bar u(0,1); // { dg-message "sorry, unimplemented: passing arguments= to ellipsis" } + } + } + + namespace no_arg_before_ellipsis { + namespace without_template { + struct foo { + constexpr foo(...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bar : boo { + using boo::boo; + }; + void f() noexcept(noexcept(bar{0})); + bar u(0); // { dg-message "sorry, unimplemented: passing arguments t= o ellipsis" } + } + + namespace with_template { + struct foo { + template + constexpr foo(...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bar : boo { + using boo::boo; + }; + void f() noexcept(noexcept(bar{0})); + bar u(0); // { dg-message "sorry, unimplemented: passing arguments t= o ellipsis" } + } + } +} + +// Now, instead of instantiating a class that uses a derived ctor, we +// introduce another template ctor that will use the varargs ctor to +// initialize its base class. The idea is to verify that the error +// message is issued, even if the instantiation occurs in a +// nonevaluated context, e.g., for constexpr templates. In the +// inherited_derived_ctor, we check that even an inherited ctor of a +// constexpr ctor is instantiated and have an error message issued. +namespace derived_ctor { + namespace direct_derived_ctor { + namespace constexpr_noninherited_ctor { + struct foo { + template + constexpr foo(T, ...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bar : boo { + template + constexpr bar(T ... args) : boo(args...) {} // { dg-message "sorry, unimp= lemented: passing arguments to ellipsis" } + }; + void f() noexcept(noexcept(bar{0,1})); + } + + namespace no_constexpr_noninherited_ctor { + struct foo { + template + constexpr foo(T, ...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bar : boo { + template + /* constexpr */ bar(T ... args) : boo(args...) {} + }; + void f() noexcept(noexcept(bar{0,1})); + } + } + + namespace inherited_derived_ctor { + namespace constexpr_noninherited_ctor { + struct foo { + template + constexpr foo(T, ...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bor : boo { + template + constexpr bor(T ... args) : boo(args...) {} // { dg-message "sorry, unimp= lemented: passing arguments to ellipsis" } + }; + struct bar : bor { + using bor::bor; + }; + void f() noexcept(noexcept(bar{0,1})); // { dg-message "'constexpr' = expansion" } + } + + namespace no_constexpr_noninherited_ctor { + struct foo { + template + constexpr foo(T, ...) {} + }; + struct boo : foo { + using foo::foo; + }; + struct bor : boo { + template + /* constexpr */ bor(T ... args) : boo(args...) {} + }; + struct bar : bor { + using bor::bor; + }; + void f() noexcept(noexcept(bar{0,1})); + } + } +} --=20 Alexandre Oliva, freedom fighter https://FSFLA.org/blogs/lxo Be the change, be Free! FSF Latin America board member GNU Toolchain Engineer Free Software Evangelist Hay que enGNUrecerse, pero sin perder la terGNUra jam=C3=A1s-GNUChe