From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752442AbdBJRET (ORCPT ); Fri, 10 Feb 2017 12:04:19 -0500 Received: from mail.kernel.org ([198.145.29.136]:46564 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751577AbdBJRES (ORCPT ); Fri, 10 Feb 2017 12:04:18 -0500 Date: Fri, 10 Feb 2017 14:03:17 -0300 From: Arnaldo Carvalho de Melo To: Steven Rostedt Cc: Namhyung Kim , Jiri Olsa , Linux Kernel Mailing List Subject: [PATCH] building libtraceevent with clang Message-ID: <20170210170317.GA14313@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Steven, I tried building perf (and thus libtraceevent) with clang and got this one: kbuffer-parse.c:312:7: warning: variable 'length' is used uninitialized whenever switch case is taken [-Wsometimes-uninitialized] case OLD_RINGBUF_TYPE_TIME_EXTEND: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ kbuffer-parse.c:339:29: note: uninitialized use occurs here kbuf->next = kbuf->index + length; ^~~~~~ kbuffer-parse.c:297:21: note: initialize the variable 'length' to silence this warning unsigned int length; ^ = 0 1 warning generated. Please take a look if the following is what should be done: diff --git a/tools/lib/traceevent/kbuffer-parse.c b/tools/lib/traceevent/kbuffer-parse.c index 65984f1c2974..3f717294cb82 100644 --- a/tools/lib/traceevent/kbuffer-parse.c +++ b/tools/lib/traceevent/kbuffer-parse.c @@ -309,20 +309,20 @@ static unsigned int old_update_pointers(struct kbuffer *kbuf) kbuf->next = kbuf->size; return 0; - case OLD_RINGBUF_TYPE_TIME_EXTEND: - extend = read_4(kbuf, ptr); - extend <<= TS_SHIFT; - extend += delta; - delta = extend; - ptr += 4; - break; - case OLD_RINGBUF_TYPE_TIME_STAMP: /* should never happen! */ kbuf->curr = kbuf->size; kbuf->next = kbuf->size; kbuf->index = kbuf->size; return -1; + + case OLD_RINGBUF_TYPE_TIME_EXTEND: + extend = read_4(kbuf, ptr); + extend <<= TS_SHIFT; + extend += delta; + delta = extend; + ptr += 4; + /* Fall through */ default: if (len) length = len * 4;