From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 99827 invoked by alias); 26 Feb 2015 08:39:38 -0000 Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org Received: (qmail 99817 invoked by uid 89); 26 Feb 2015 08:39:37 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=3.9 required=5.0 tests=AWL,BAYES_50,FREEMAIL_FROM,KAM_FROM_URIBL_PCCC,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=no version=3.3.2 X-HELO: mail-ig0-f177.google.com Received: from mail-ig0-f177.google.com (HELO mail-ig0-f177.google.com) (209.85.213.177) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Thu, 26 Feb 2015 08:39:36 +0000 Received: by mail-ig0-f177.google.com with SMTP id z20so12738964igj.4 for ; Thu, 26 Feb 2015 00:39:34 -0800 (PST) MIME-Version: 1.0 X-Received: by 10.42.71.194 with SMTP id l2mr8172147icj.71.1424939974090; Thu, 26 Feb 2015 00:39:34 -0800 (PST) Received: by 10.107.136.80 with HTTP; Thu, 26 Feb 2015 00:39:34 -0800 (PST) In-Reply-To: References: <0AB56024-875B-4724-8ED2-A9DDB237CBFF@dell.com> <23CC7871-C616-436C-920C-4A635DC87189@dell.com> <7A311B56-C424-4C4F-A0E4-B12B65131745@gmail.com> <225BDA7A-3A1F-4F94-8086-E44249E273D5@gmail.com> Date: Thu, 26 Feb 2015 09:52:00 -0000 Message-ID: Subject: Re: format string is not a string literal From: Jack Howarth To: Andrew Pinski Cc: Simon Marchi , "Paul_Koning@dell.com" , "gdb@sourceware.org" Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2015-02/txt/msg00063.txt.bz2 On Wed, Feb 25, 2015 at 9:38 PM, Andrew Pinski wrote: > On Wed, Feb 25, 2015 at 6:35 PM, Andrew Pinski wrote: >> On Wed, Feb 25, 2015 at 6:30 PM, Simon Marchi wrote: >>>>> On Feb 25, 2015, at 4:41 PM, Jack Howarth wrote: >>>>> >>>>> Andrew, >>>>> See the additional comments from the llvm.org clang developers at... >>>>> >>>>> http://llvm.org/bugs/show_bug.cgi?id=22701#c5 >>>> >>>> Then put this warning under a different flag. Anyways clang is broken and gdb should not change due to a broken compiler. >>>> >>>> Thanks, >>>> Andrew >>> >>> I would not say that clang is broken or that the warning is unclear. >>> The flag is -Wformat-nonliteral and the warning message is "format >>> string is not a string literal". I don't know how you can be more >>> clear and direct about the fact that the format string is not a string >>> literal. Looking at the code, we observe that clang is right (the >>> format string is indeed not a string literal). With the proper >>> function attributes, the compiler could do better checks and prevent >>> programming mistakes. Since clang pointed out this low-hanging fruit >>> improvement to gdb's code, why shouldn't we take advantage of it? >>> >>> Anyway, Jack, you are welcome to submit a patch for this if you feel >>> like it and/or file a bug if it is not already done. >> >> >> Except GCC documents this options differently than clang implements: >> -Wformat-nonliteralIf -Wformat is specified, also warn if the format >> string is not a string literal and so cannot be checked, unless the >> format function takes its format arguments as a va_list. >> >> >> Notice the last part of the documentation. >> >> So this again is clang implements a GCC option but does not follow the >> documentation of GCC. >> How does clang document this option? >> > > GCC has always documented this option this way since at least 3.1.1: > https://gcc.gnu.org/onlinedocs/gcc-3.1.1/gcc/Warning-Options.html#Warning%20Options > > And there is no user documentation for clang for this option so clang is broken. http://clang.llvm.org/docs/AttributeReference.html#format-gnu-format > > Thanks, > Andrew > > > >> Thanks, >> Andrew >> >>> >>> Simon