From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11373 invoked by alias); 30 Sep 2016 16:43:45 -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 11361 invoked by uid 89); 30 Sep 2016 16:43:44 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-4.9 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=sk:indisti, eq_expr, EQ_EXPR, input_location 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, 30 Sep 2016 16:43:43 +0000 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BF2EC7CDF9 for ; Fri, 30 Sep 2016 16:43:40 +0000 (UTC) Received: from redhat.com (ovpn-204-20.brq.redhat.com [10.40.204.20]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u8UGhbnQ003580 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 30 Sep 2016 12:43:39 -0400 Date: Fri, 30 Sep 2016 16:52:00 -0000 From: Marek Polacek To: Jason Merrill Cc: GCC Patches Subject: Re: C/C++ PATCH to implement -Wpointer-compare warning (PR c++/64767) Message-ID: <20160930164337.GE3223@redhat.com> References: <20160910145843.GJ19950@redhat.com> <20160915121631.GY19950@redhat.com> <20160923131537.GB3223@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.7.0 (2016-08-17) X-SW-Source: 2016-09/txt/msg02381.txt.bz2 On Fri, Sep 23, 2016 at 10:31:33AM -0400, Jason Merrill wrote: > On Fri, Sep 23, 2016 at 9:15 AM, Marek Polacek wrote: > > On Wed, Sep 21, 2016 at 03:52:09PM -0400, Jason Merrill wrote: > >> On Mon, Sep 19, 2016 at 2:49 PM, Jason Merrill wrote: > >> > I suppose that an INTEGER_CST of character type is necessarily a > >> > character constant, so adding a check for !char_type_p ought to do the > >> > trick. > >> > >> Indeed it does. I'm checking this in: > > > > Nice, thanks. What about the original patch? We still need to warn > > (or error for C++11) for pointer comparisons. > > If we still accept pointer comparisons in C++, that's another bug with > treating \0 as a null pointer constant. This seems to be because > ocp_convert of \0 to int produces an INTEGER_CST indistinguishable > from literal 0. I was trying to fix this in ocp_convert, by using NOP_EXPRs, but that wasn't successful. But since we're interested in ==/!=, I think this can be fixed easily in cp_build_binary_op. Actually, all that seems to be needed is using orig_op as the argument to null_ptr_cst_p, but that wouldn't give the correct diagnostics, so I did this. By checking orig_op we can see if the operands are character literals or not, because orig_op is an operand before the default conversions. Curiously, nothing in the testsuite broke. Bootstrapped/regtested on x86_64-linux and ppc64-linux, ok for trunk? 2016-09-30 Marek Polacek Core 903 * typeck.c (cp_build_binary_op) [EQ_EXPR]: Diagnose invalid pointer conversions. * g++.dg/cpp0x/nullptr37.C: New test. diff --git gcc/cp/typeck.c gcc/cp/typeck.c index 617ca55..2e6f44e 100644 --- gcc/cp/typeck.c +++ gcc/cp/typeck.c @@ -4584,6 +4584,14 @@ cp_build_binary_op (location_t location, else result_type = type0; + if (null_ptr_cst_p (op1) && !null_ptr_cst_p (orig_op1)) + { + if (complain & tf_error) + permerror (input_location, "ISO C++11 only allows pointer " + "conversions for integer literals"); + else + return error_mark_node; + } warn_for_null_address (location, op0, complain); } else if (((code1 == POINTER_TYPE || TYPE_PTRDATAMEM_P (type1)) @@ -4598,6 +4606,14 @@ cp_build_binary_op (location_t location, else result_type = type1; + if (null_ptr_cst_p (op0) && !null_ptr_cst_p (orig_op0)) + { + if (complain & tf_error) + permerror (input_location, "ISO C++11 only allows pointer " + "conversions for integer literals"); + else + return error_mark_node; + } warn_for_null_address (location, op1, complain); } else if ((code0 == POINTER_TYPE && code1 == POINTER_TYPE) diff --git gcc/testsuite/g++.dg/cpp0x/nullptr37.C gcc/testsuite/g++.dg/cpp0x/nullptr37.C index e69de29..17c33d1 100644 --- gcc/testsuite/g++.dg/cpp0x/nullptr37.C +++ gcc/testsuite/g++.dg/cpp0x/nullptr37.C @@ -0,0 +1,78 @@ +/* PR c++/64767 */ +// { dg-do compile { target c++11 } } + +int +f1 (int *p, int **q) +{ + int r = 0; + + r += p == '\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += p == L'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += p == u'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += p == U'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += p != '\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += p != L'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += p != u'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += p != U'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + + r += '\0' == p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += L'\0' == p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += u'\0' == p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += U'\0' == p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += '\0' != p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += L'\0' != p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += u'\0' != p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += U'\0' != p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + + r += q == '\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += q == L'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += q == u'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += q == U'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += q != '\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += q != L'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += q != u'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += q != U'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + + r += '\0' == q; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += L'\0' == q; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += u'\0' == q; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += U'\0' == q; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += '\0' != q; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += L'\0' != q; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += u'\0' != q; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += U'\0' != q; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + + return r; +} + +int +f2 (int *p) +{ + int r = 0; + + r += p == (void *) 0; + r += p != (void *) 0; + r += (void *) 0 == p; + r += (void *) 0 != p; + + r += p == 0; + r += p != 0; + r += 0 == p; + r += 0 != p; + + return r; +} + +int +f3 (int *p) +{ + int r = 0; + + r += p == (char) 0; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += p != (char) 0; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + + r += (char) 0 == p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + r += (char) 0 != p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions for integer literals" } */ + + return r; +} Marek