From patchwork Thu Jan 10 15:22:07 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dodji Seketeli X-Patchwork-Id: 211061 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) by ozlabs.org (Postfix) with SMTP id 3CDA12C0223 for ; Fri, 11 Jan 2013 02:22:36 +1100 (EST) Comment: DKIM? See http://www.dkim.org DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d=gcc.gnu.org; s=default; x=1358436157; h=Comment: DomainKey-Signature:Received:Received:Received:Received:Received: Received:From:To:Cc:Subject:References:Date:In-Reply-To: Message-ID:User-Agent:MIME-Version:Content-Type:Mailing-List: Precedence:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:Sender:Delivered-To; bh=YfYsM/Uw4MtTsfZ8kkGXfiWlYK8=; b=q3DsI0inlfqbzyeLwmx1wgJJ9finWGzjeEjaUD/THxdcyvjXIF8LqsOZ/pMGn5 bLGzaB6RZUZT+uQp0IyA4YgZ2RR+P8gcjhU9TMWycC4aHynvpsRpbrppiVgEDTjE LjCaVLJSPq0WtOz8im/DlKBo9xwEyDic6M91gSuxlEoFo= Comment: DomainKeys? See http://antispam.yahoo.com/domainkeys DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=gcc.gnu.org; h=Received:Received:X-SWARE-Spam-Status:X-Spam-Check-By:Received:Received:Received:Received:From:To:Cc:Subject:References:X-URL:Date:In-Reply-To:Message-ID:User-Agent:MIME-Version:Content-Type:Mailing-List:Precedence:List-Id:List-Unsubscribe:List-Archive:List-Post:List-Help:Sender:Delivered-To; b=cHj3K7EPRpR3qeiSmQ7piQ3cJ97rfGW90rP04kXP0vdkwLh7E06f9wbiiMcGHw /1nhUXHAixWqFY3Ni8GZndbU43MD1rtWvUHBALY4c/5sFkLElJSE6uf5f5p5oEVy oxHbnYjZL3Lb69K8IHYcTEW7gDj1x4+7O8UMdgYftv3Lo=; Received: (qmail 20472 invoked by alias); 10 Jan 2013 15:22:22 -0000 Received: (qmail 20461 invoked by uid 22791); 10 Jan 2013 15:22:20 -0000 X-SWARE-Spam-Status: No, hits=-6.1 required=5.0 tests=AWL, BAYES_00, KHOP_RCVD_UNTRUST, RCVD_IN_DNSWL_HI, RCVD_IN_HOSTKARMA_W, RP_MATCHES_RCVD, SPF_HELO_PASS X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 10 Jan 2013 15:22:12 +0000 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r0AFMBj3024014 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 10 Jan 2013 10:22:11 -0500 Received: from localhost (ovpn-116-53.ams2.redhat.com [10.36.116.53]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r0AFM9vJ015553 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 10 Jan 2013 10:22:10 -0500 Received: by localhost (Postfix, from userid 1000) id 454539F1A4; Thu, 10 Jan 2013 16:22:08 +0100 (CET) From: Dodji Seketeli To: Gabriel Dos Reis Cc: GCC Patches , Jason Merrill Subject: Re: [PATCH] PR c++/55663 - constexpr function templ instantiation considered non-const as alias templ arg References: <877gnnwzdg.fsf@redhat.com> <87hamqtlum.fsf@redhat.com> X-URL: http://www.redhat.com Date: Thu, 10 Jan 2013 16:22:07 +0100 In-Reply-To: (Gabriel Dos Reis's message of "Wed, 9 Jan 2013 10:14:43 -0600") Message-ID: <87k3rlrrkw.fsf@redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.2 (gnu/linux) MIME-Version: 1.0 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Delivered-To: mailing list gcc-patches@gcc.gnu.org Gabriel Dos Reis writes: > I read your reply. I am now even more puzzled > than before. The call to uses_template_parm indicates that > we expect that code to work when are also when processing a template > (e.g. for non-dependent cases inside a template.) > That makes me wonder how it could possibly work for the > cases at hand because for non-type template arguments we need > full instantiation information to determine convertibility and > "constant"ness. I introduced the confusion, sorry. I overlooked the fact that this is actually happening while calling instantiate_alias_template on Alias with the argument the_thruth non folded. In that code patch, we didn't even go through convert_template_argument like what I was saying. More on this below. Jason Merrill writes: > On 01/09/2013 10:02 AM, Dodji Seketeli wrote: >> As the argument 'the_truth()' we care about is type dependant, >> uses_template_parms returns true and so convert_nontype_argument is >> never called. > > Right, but we should call it for the instantiated argument, too. We > do that for class templates by calling lookup_template_class again, > which calls coerce_template_parms. We need to make sure we call > coerce_template_parms when instantiating alias templates, too. Indeed. The problem is happening during the instantiation of test using instantiate_class_template. In that case the argument {int} was previously properly coerced and stored in CLASSTYPE_TI_ARGS by lookup_class_template, as you are saying. So instantiate_class_template always uses coerced arguments. But during the instantiation of the *members* of test, we try to instantiate Alias>, without coercing (and thus without folding) the argument {the_truth}. We do this using instantiate_alias_template, called from tsubst. The patch below makes sure instantiate_alias_template coerces the arguments it uses to instantiate the alias template, like what I understood you are suggesting. I have tested it without boostrap and a full boostrap is currently running. If this approach looks acceptable, could I replace (part of) the template argument coercing code in lookup_class_template_1 with the new coerce_template_parms_all_level I introduced in this patch? Also, I am not sure if this patch would be appropriate for commit, now that we are in 'regression-only' mode. But seeing this alias-template related thing not working hurts me. :) So at worst I'll schedule the patch for when stage1 opens again. Thanks. gcc/cp/ PR c++/55663 * pt.c (coerce_template_parms_all_levels): New static function. (instantiate_alias_template): Use it here. gcc/testsuite/ PR c++/55663 * g++.dg/cpp0x/alias-decl-31.C: New test. --- gcc/cp/pt.c | 64 +++++++++++++++++++++++++++++- gcc/testsuite/g++.dg/cpp0x/alias-decl-31.C | 20 ++++++++++ 2 files changed, 83 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/alias-decl-31.C diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index 30bafa0..aadc173 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -130,6 +130,8 @@ static tree tsubst_initializer_list (tree, tree); static tree get_class_bindings (tree, tree, tree, tree); static tree coerce_template_parms (tree, tree, tree, tsubst_flags_t, bool, bool); +static tree coerce_template_parms_all_levels (tree, tree, tree, tsubst_flags_t, + bool, bool); static void tsubst_enum (tree, tree, tree); static tree add_to_template_args (tree, tree); static tree add_outermost_template_args (tree, tree); @@ -6742,6 +6744,58 @@ coerce_template_parms (tree parms, return new_inner_args; } +/* Like coerce_template_parms. If PARMS represents all template + parameters levels, this function returns a vector of vectors + representing all the resulting argument levels. Note that in this + case, only the innermost arguments are coerced because the + outermost ones are supposed to have been coerced already. + + Otherwise, if PARMS represents only (the innermost) vectors of + parameters, returns a vector containing just the innermost + resulting arguments. */ + +static tree +coerce_template_parms_all_levels (tree parms, + tree args, + tree in_decl, + tsubst_flags_t complain, + bool require_all_args, + bool use_default_args) +{ + int parms_depth = TMPL_PARMS_DEPTH (parms); + int args_depth = TMPL_ARGS_DEPTH (args); + tree coerced_args; + + if (parms_depth > 1) + { + coerced_args = make_tree_vec (parms_depth); + tree level; + int cur_depth; + + for (level = parms, cur_depth = parms_depth; + parms_depth > 0 && level != NULL_TREE; + level = TREE_CHAIN (level), --cur_depth) + { + tree l; + if (cur_depth == args_depth) + l = coerce_template_parms (TREE_VALUE (level), + args, in_decl, complain, + require_all_args, + use_default_args); + else + l = TMPL_ARGS_LEVEL (args, cur_depth); + + SET_TMPL_ARGS_LEVEL (coerced_args, cur_depth, l); + } + } + else + coerced_args = coerce_template_parms (INNERMOST_TEMPLATE_PARMS (parms), + args, in_decl, complain, + require_all_args, + use_default_args); + return coerced_args; +} + /* Returns 1 if template args OT and NT are equivalent. */ static int @@ -14637,7 +14691,15 @@ instantiate_alias_template (tree tmpl, tree args, tsubst_flags_t complain) ggc_free (tinst); return error_mark_node; } - tree r = instantiate_template (tmpl, args, complain); + + tree coerced_args = + coerce_template_parms_all_levels (DECL_TEMPLATE_PARMS (tmpl), + args, tmpl, complain, + /*require_all_args=*/true, + /*use_default_args=*/true); + + tree r = instantiate_template (tmpl, coerced_args, complain); + pop_tinst_level (); /* We can't free this if a pending_template entry or last_error_tinst_level is pointing at it. */ diff --git a/gcc/testsuite/g++.dg/cpp0x/alias-decl-31.C b/gcc/testsuite/g++.dg/cpp0x/alias-decl-31.C new file mode 100644 index 0000000..83eea47 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/alias-decl-31.C @@ -0,0 +1,20 @@ +// Origin: PR c++/55663 +// { dg-do compile { target c++11 } } + +template +constexpr bool the_truth () { return true; } + +template + struct Takes_bool { }; + +template + using Alias = Takes_bool; + +template + struct test { using type = Alias()>; }; + +int main () { + test a; + + return 0; +}