From owner-freebsd-current@FreeBSD.ORG Fri Nov 4 21:21:28 2011 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8BF111065673; Fri, 4 Nov 2011 21:21:28 +0000 (UTC) (envelope-from loox@e-shell.net) Received: from mail.serpronet.com (mail.serpronet.com [64.214.84.187]) by mx1.freebsd.org (Postfix) with ESMTP id 608788FC08; Fri, 4 Nov 2011 21:21:28 +0000 (UTC) Received: by mail.serpronet.com (Postfix, from userid 506) id 42A5CC4BB9; Fri, 4 Nov 2011 15:21:27 -0600 (CST) X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on titan.serpronet.com X-Spam-Level: X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED,BAYES_00 autolearn=ham version=3.2.5 Received: from twinmoon.e-shell.net (unknown [10.1.10.180]) by mail.serpronet.com (Postfix) with ESMTP id B9460C4BB4; Fri, 4 Nov 2011 15:21:24 -0600 (CST) Received: from moonlight.e-shell.tk (unknown [189.247.86.136]) by twinmoon.e-shell.net (Postfix) with ESMTPSA id 7359217021; Fri, 4 Nov 2011 15:22:44 -0600 (CST) From: Axel Gonzalez To: freebsd-current@freebsd.org Date: Fri, 04 Nov 2011 15:21:21 -0600 Message-ID: <3103300.opx6oxscCi@moonlight.e-shell.tk> User-Agent: KMail/4.7.1 (FreeBSD/9.0-RC1; KDE/4.7.2; i386; ; ) In-Reply-To: <2104381.NqWTZMXtng@moonlight.e-shell.tk> References: <1562351.Ln9lEKl2rv@moonlight.e-shell.tk> <20111101065651.GA27751@freebsd.org> <2104381.NqWTZMXtng@moonlight.e-shell.tk> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Cc: Roman Divacky Subject: bug in clang printf format | was Re: Strange warning with clang and 9RC1 (ntohs) X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 04 Nov 2011 21:21:28 -0000 After getting in contact with clang's ml, the determined that this a bug in clang's format checker. Note that this bug affects: printf("%hu\n", ntohs(x)); This happens in 9 that ntohs is defined as a macro using conditinal operator (? :) The discussion is here: http://lists.cs.uiuc.edu/pipermail/cfe-dev/2011-November/018464.html The bug in clang is here: http://llvm.org/bugs/show_bug.cgi?id=11313 Greetings! On Tuesday 01 November 2011 01:10:36 Axel Gonzalez wrote: > Here is the output (short version): > > ... > (snip) > > static __inline __uint16_t > __bswap16_var(__uint16_t _x) > { > > return ((__uint16_t)((_x) << 8 | (_x) >> 8)); > } > > ... > (snip) > > > int main() > { > uint16_t x = (__builtin_constant_p(80) ? (__uint16_t)(((__uint16_t)(80)) << > 8 > | ((__uint16_t)(80)) >> 8) : __bswap16_var(80)); > > printf("%hu\n", (uint16_t)(__builtin_constant_p(x) ? (__uint16_t) > (((__uint16_t)(x)) << 8 | ((__uint16_t)(x)) >> 8) : __bswap16_var(x))); > printf("%hu\n", (__builtin_constant_p(x) ? (__uint16_t)(((__uint16_t)(x)) > << 8 | ((__uint16_t)(x)) >> 8) : __bswap16_var(x))); > return (0); > } > > > % clang -E ntohs.c > ntohs_.c > % clang -Wall -o ntohs ntohs_.c > In file included from ntohs.c:1: > ntohs.c:8:12: warning: conversion specifies type 'unsigned short' but the > argument has type > 'int' [-Wformat] > ...%hu\n", (__builtin_constant_p(x) ? (__uint16_t)(((__uint16_t)(x)) << 8 > | ((__uint16_t)(x)) >> 8) : __bswap16_var(x))... > ~~^ > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ %d > 1 warning generated. > > > > And I missed it the first mail: > > FreeBSD moonlight 9.0-RC1 FreeBSD 9.0-RC1 #0: Fri Oct 28 22:53:45 CDT 2011 > toor@moonlight:/usr/obj/usr/src/sys/LXCORE9 i386 > > > Thanks! > > A > > On Tuesday 01 November 2011 07:56:51 Roman Divacky wrote: > > It doesnt warn here. Can you check with "clang -E" what the ntohs() > > is being expanded to and what the real prototype is? -- Fri Nov 4 15:11:00 2011 GMT ** ****** ********* ********** ********** ********* ****** ** 9.