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Tue, 5 Dec 2023 17:00:34 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.195.157]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 26577492BC6; Tue, 5 Dec 2023 17:00:34 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 3B5H0Vf92959751 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 5 Dec 2023 18:00:32 +0100 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 3B5H0V802959750; Tue, 5 Dec 2023 18:00:31 +0100 Date: Tue, 5 Dec 2023 18:00:31 +0100 From: Jakub Jelinek To: Jason Merrill , Marek Polacek Cc: gcc-patches@gcc.gnu.org Subject: [PATCH] c++, v2: Fix parsing [[]][[]]; Message-ID: References: MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline X-Spam-Status: No, score=-3.4 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, 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: 2.1.30 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Jakub Jelinek Errors-To: gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1784462092437262117 X-GMAIL-MSGID: 1784462092437262117 On Tue, Dec 05, 2023 at 09:45:32AM -0500, Marek Polacek wrote: > > When working on the previous patch I put [[]] [[]] asm (""); into a > > testcase, but was surprised it wasn't parsed. > > By wasn't parsed you mean we gave an error, right? I only see an error > with block-scope [[]] [[]];. Yeah. The reason why [[]][[]]; works at namespace scope is that if else if (cp_lexer_nth_token_is (parser->lexer, cp_parser_skip_std_attribute_spec_seq (parser, 1), CPP_SEMICOLON)) which is the case here then even if after parsing the attributes next token isn't CPP_SEMICOLON (the case here without the patch), it will just return and another cp_parser_declaration will parse another [[]], that time also with CPP_SEMICOLON. > It seems marginally better to me to use void_list_node so that we don't > need a new parm, like what we do when parsing parameters: ()/(void)/(...), > but I should let others decide. Here is a modified version of the patch which does it like that. 2023-12-05 Jakub Jelinek * parser.cc (cp_parser_std_attribute_spec): Return void_list_node rather than NULL_TREE if token is neither CPP_OPEN_SQUARE nor RID_ALIGNAS CPP_KEYWORD. (cp_parser_std_attribute_spec_seq): For attr_spec == void_list_node break, for attr_spec == NULL_TREE continue. * g++.dg/cpp0x/gen-attrs-79.C: New test. Jakub --- gcc/cp/parser.cc.jj 2023-12-05 16:18:32.224909370 +0100 +++ gcc/cp/parser.cc 2023-12-05 17:07:34.690170639 +0100 @@ -30244,7 +30244,11 @@ void cp_parser_late_contract_condition ( [ [ assert : contract-mode [opt] : conditional-expression ] ] [ [ pre : contract-mode [opt] : conditional-expression ] ] [ [ post : contract-mode [opt] identifier [opt] : - conditional-expression ] ] */ + conditional-expression ] ] + + Return void_list_node if the current token doesn't start an + attribute-specifier to differentiate from NULL_TREE returned e.g. + for [ [ ] ]. */ static tree cp_parser_std_attribute_spec (cp_parser *parser) @@ -30324,7 +30328,7 @@ cp_parser_std_attribute_spec (cp_parser if (token->type != CPP_KEYWORD || token->keyword != RID_ALIGNAS) - return NULL_TREE; + return void_list_node; cp_lexer_consume_token (parser->lexer); maybe_warn_cpp0x (CPP0X_ATTRIBUTES); @@ -30397,8 +30401,12 @@ cp_parser_std_attribute_spec_seq (cp_par while (true) { tree attr_spec = cp_parser_std_attribute_spec (parser); - if (attr_spec == NULL_TREE) + if (attr_spec == void_list_node) break; + /* Accept [[]][[]]; for which cp_parser_std_attribute_spec + returns NULL_TREE as there are no attributes. */ + if (attr_spec == NULL_TREE) + continue; if (attr_spec == error_mark_node) return error_mark_node; --- gcc/testsuite/g++.dg/cpp0x/gen-attrs-79.C.jj 2023-12-05 17:04:14.235988879 +0100 +++ gcc/testsuite/g++.dg/cpp0x/gen-attrs-79.C 2023-12-05 17:04:14.235988879 +0100 @@ -0,0 +1,9 @@ +// { dg-do compile { target c++11 } } + +[[]] [[]]; + +[[]] [[]] void +foo () +{ + [[]] [[]]; +}