From patchwork Sun Jun 25 21:12:07 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Carlini X-Patchwork-Id: 780532 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]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3wwlJB3NdSz9s2G for ; Mon, 26 Jun 2017 07:12:25 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=gcc.gnu.org header.i=@gcc.gnu.org header.b="X7CuCrD5"; dkim-atps=neutral DomainKey-Signature: a=rsa-sha1; c=nofws; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:to:cc :from:subject:message-id:date:mime-version:content-type; q=dns; s=default; b=X3MzYPWkmdHabQNSt2rp+qS+HwTXQjFavGuuEP6M7w9cJN3GEf eqG0WEfSyQSRGLXlficUo3IqUk8LTTR24buOQi9tEAYyNStVqd/msfiwzlEbmyDc g0lH283iC9OcemriDVKFYrmeMJuOFkJ+Rj81rv8ysIvnsOcfNRG7d52Jk= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:to:cc :from:subject:message-id:date:mime-version:content-type; s= default; bh=RB1u4lrXO2zqx6B8GKFu4NtYIsI=; b=X7CuCrD5F8O6cyIlNSUw jvCAr1Lw7pg3m79Bm0r9479mHNmT5xo2PA/siGzecjzIyDHxnhc9zwA8F29PCuES CvN+KBNaRNoPxZiMD0VPYz0w1hL9sD+fW61HbICRxx8F5XD38yCPaboGw5DCSdTI J5PtLr4Z7lwujJlSnWuH8Do= Received: (qmail 123390 invoked by alias); 25 Jun 2017 21:12:16 -0000 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 Received: (qmail 123377 invoked by uid 89); 25 Jun 2017 21:12:15 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-10.1 required=5.0 tests=BAYES_00, GIT_PATCH_2, GIT_PATCH_3, KAM_ASCII_DIVIDERS, KAM_LAZY_DOMAIN_SECURITY, RP_MATCHES_RCVD autolearn=ham version=3.3.2 spammy= X-HELO: aserp1040.oracle.com Received: from aserp1040.oracle.com (HELO aserp1040.oracle.com) (141.146.126.69) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Sun, 25 Jun 2017 21:12:13 +0000 Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id v5PLCBQc024843 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 25 Jun 2017 21:12:12 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id v5PLCBbT027537 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 25 Jun 2017 21:12:11 GMT Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id v5PLCAkT023630; Sun, 25 Jun 2017 21:12:10 GMT Received: from [192.168.1.4] (/87.16.215.96) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 25 Jun 2017 14:12:10 -0700 To: "gcc-patches@gcc.gnu.org" Cc: Jason Merrill From: Paolo Carlini Subject: [C++ Patch] PR 65775 ("Late-specified return type bypasses return type checks (qualified, function, array)") Message-ID: Date: Sun, 25 Jun 2017 23:12:07 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.0 MIME-Version: 1.0 X-IsSubscribed: yes Hi, in grokdeclarator the checks on the return type do nothing useful in case of late-specified return type because they happen too early, before splice_late_return_type is called. A straightforward way to solve the problem involves separating the checks themselves to a new check_function_return_type and calling it again only in case splice_late_return_type actually spliced the late return type (in that case, we should also consistently update type_quals). As a side issue, if we want to use good and consistent locations for the error messages (the testcase below checks that too), we need a fall back to input_location for typespec_loc, because otherwise an UNKNOWN_LOCATION is used for the error messages of testcases like lambda-syntax1.C and pr60190.C. Tested x86_64-linux. Thanks, Paolo. ///////////////////// /cp 2017-06-25 Paolo Carlini PR c++/65775 * decl.c (check_function_return_type): New. (grokdeclarator): Use the latter; if declspecs->locations[ds_type_spec] is UNKNOWN_LOCATION fall back to input_location. /testsuite 2017-06-25 Paolo Carlini PR c++/65775 * g++.dg/cpp0x/trailing14.C: New. Index: testsuite/g++.dg/cpp0x/trailing14.C =================================================================== --- testsuite/g++.dg/cpp0x/trailing14.C (revision 0) +++ testsuite/g++.dg/cpp0x/trailing14.C (working copy) @@ -0,0 +1,15 @@ +// PR c++/65775 +// { dg-do compile { target c++11 } } +// { dg-options "-Wignored-qualifiers" } + +using Qi = int const volatile; +Qi q1(); // { dg-warning "1: type qualifiers ignored" } +auto q2() -> Qi; // { dg-warning "1: type qualifiers ignored" } + +using Fi = int(); +Fi f1(); // { dg-error "1: 'f1' declared as function returning a function" } +auto f2() -> Fi; // { dg-error "1: 'f2' declared as function returning a function" } + +using Ai = int[5]; +Ai a1(); // { dg-error "1: 'a1' declared as function returning an array" } +auto a2() -> Ai; // { dg-error "1: 'a2' declared as function returning an array" } Index: cp/decl.c =================================================================== --- cp/decl.c (revision 249632) +++ cp/decl.c (working copy) @@ -9789,7 +9789,43 @@ mark_inline_variable (tree decl) } } +/* If TYPE has TYPE_QUALS != TYPE_UNQUALIFIED issue a warning controlled by + -Wignored-qualifiers and clear TYPE_QUALS to avoid cascading diagnostics. + If TYPE is not valid, issue an error message and return error_mark_node, + otherwise return TYPE itself. */ +static tree +check_function_return_type (tree type, int& type_quals, + const char* name, location_t loc) +{ + if (type_quals != TYPE_UNQUALIFIED) + { + if (SCALAR_TYPE_P (type) || VOID_TYPE_P (type)) + warning_at (loc, OPT_Wignored_qualifiers, "type " + "qualifiers ignored on function return type"); + + /* We now know that the TYPE_QUALS don't apply to the + decl, but to its return type. */ + type_quals = TYPE_UNQUALIFIED; + } + + /* Error about some types functions can't return. */ + + if (TREE_CODE (type) == FUNCTION_TYPE) + { + error_at (loc, "%qs declared as function returning a function", name); + return error_mark_node; + } + + if (TREE_CODE (type) == ARRAY_TYPE) + { + error_at (loc, "%qs declared as function returning an array", name); + return error_mark_node; + } + + return type; +} + /* Assign a typedef-given name to a class or enumeration type declared as anonymous at first. This was split out of grokdeclarator because it is also used in libcc1. */ @@ -9993,6 +10029,8 @@ grokdeclarator (const cp_declarator *declarator, declspecs->locations); if (typespec_loc == UNKNOWN_LOCATION) typespec_loc = declspecs->locations[ds_type_spec]; + if (typespec_loc == UNKNOWN_LOCATION) + typespec_loc = input_location; /* Look inside a declarator for the name being declared and get it as a string, for an error message. */ @@ -10828,31 +10866,10 @@ grokdeclarator (const cp_declarator *declarator, /* Declaring a function type. Make sure we have a valid type for the function to return. */ - if (type_quals != TYPE_UNQUALIFIED) - { - if (SCALAR_TYPE_P (type) || VOID_TYPE_P (type)) - { - warning_at (typespec_loc, OPT_Wignored_qualifiers, "type " - "qualifiers ignored on function return type"); - } - /* We now know that the TYPE_QUALS don't apply to the - decl, but to its return type. */ - type_quals = TYPE_UNQUALIFIED; - } + if (check_function_return_type (type, type_quals, name, typespec_loc) + == error_mark_node) + return error_mark_node; - /* Error about some types functions can't return. */ - - if (TREE_CODE (type) == FUNCTION_TYPE) - { - error ("%qs declared as function returning a function", name); - return error_mark_node; - } - if (TREE_CODE (type) == ARRAY_TYPE) - { - error ("%qs declared as function returning an array", name); - return error_mark_node; - } - input_location = declspecs->locations[ds_type_spec]; abstract_virtuals_error (ACU_RETURN, type); input_location = saved_loc; @@ -10959,7 +10976,17 @@ grokdeclarator (const cp_declarator *declarator, return error_mark_node; if (late_return_type) - late_return_type_p = true; + { + late_return_type_p = true; + if (type == late_return_type) + { + type_quals = cp_type_quals (type); + if (check_function_return_type (type, type_quals, + name, typespec_loc) + == error_mark_node) + return error_mark_node; + } + } if (ctype == NULL_TREE && decl_context == FIELD