From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com ([134.134.136.24]:22160 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750732AbaGTVRb (ORCPT ); Sun, 20 Jul 2014 17:17:31 -0400 Date: Sun, 20 Jul 2014 14:17:30 -0700 From: Andi Kleen Subject: Re: [PATCH 2/2] Kbuild: Add a option to enable dwarf4 Message-ID: <20140720211729.GP5803@tassilo.jf.intel.com> References: <1405466172-17055-1-git-send-email-andi@firstfloor.org> <1405466172-17055-2-git-send-email-andi@firstfloor.org> <20140720192315.GA4679@ravnborg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140720192315.GA4679@ravnborg.org> Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Sam Ravnborg Cc: Andi Kleen , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org On Sun, Jul 20, 2014 at 09:23:15PM +0200, Sam Ravnborg wrote: > On Wed, Jul 16, 2014 at 01:16:12AM +0200, Andi Kleen wrote: > > From: Andi Kleen > > > > I found that a lot of unresolvable variables when using gdb on the kernel > > become resolvable when dwarf4 is enabled. So add a Kconfig flag to enable it. > > > > It definitely increases the debug information size, but on the other > > hand this isn't so bad when debug fusion is used. > > Would it not make sense to try to enable degug info like this: > First try -gdwarf-4 > If this fails try -gdwarf-3 > If this fails try -gdwarf-2 > And if this also fails fallback to -g > > We could then us a Kconfig option to enable the highest debug level - where 4 for now is the highest. > On the other hand if most people have revent utils then they all have -gdwarf-4 supported > and then it is no big deal. I made it a separate option, because dwarf4 is somewhat bigger than dwarf3 and it's probably only useful for people actively using gdb/crash (and I don't think others users like systemtap/perf probe do dwarf4 yet) If debug fusion was default it would be fine, but right now it would need converting a lot of debuginfo packaing scripts first. -Andi