From owner-freebsd-hackers Sat Aug 3 5:54:52 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3547637B400 for ; Sat, 3 Aug 2002 05:54:49 -0700 (PDT) Received: from woozle.rinet.ru (woozle.rinet.ru [195.54.192.68]) by mx1.FreeBSD.org (Postfix) with ESMTP id B4BBB43E3B for ; Sat, 3 Aug 2002 05:54:47 -0700 (PDT) (envelope-from marck@rinet.ru) Received: from localhost (marck@localhost) by woozle.rinet.ru (8.11.6/8.11.6) with ESMTP id g73Csd325944; Sat, 3 Aug 2002 16:54:44 +0400 (MSD) (envelope-from marck@rinet.ru) Date: Sat, 3 Aug 2002 16:54:39 +0400 (MSD) From: Dmitry Morozovsky To: Terry Lambert Cc: hackers@freebsd.org Subject: Re: -fomit-frame-pointer for the world build In-Reply-To: <3D4ACBC2.DB52A15C@mindspring.com> Message-ID: <20020803164434.Q25630-100000@woozle.rinet.ru> X-NCC-RegID: ru.rinet MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Fri, 2 Aug 2002, Terry Lambert wrote: TL> Dmitry Morozovsky wrote: TL> [ ... -fomit-frame-pointer ... ] TL> > Yes, Terry, I'd read this note. However, it does not clarify for me which TL> > exactly functionality is lost with omitting this. TL> > TL> > I tried to build some binaries with -fomit..., then tried to debug it a TL> > bit, and gdb shows me both backtrace stack and arguments, so I was in TL> > doubt a bit -- so here is my question ;-) TL> TL> Try it again on a SPARC or other RISC machine that pushes TL> register window frames on the stack after a certain function TL> call depth is achieved. TL> TL> I was pretty sure at one time that the PPC platform had a TL> variant of this problem, as well. Well, this clarifies much more than I test -- the only platform I tried to check this was i386. TL> If you want a definative answer, then the people to ask are TL> the GCC implementors, who put the option into the compiler TL> for a reason, and added the descriptive text to the .info TL> file in the first place. I didn't doubt it ;-) TL> Realize that this is a GCC issue, not a FreeBSD issue. What's the issue? Existence of -fomit... option? ;-) Actually, I was not specific enough in my initial question. It should sound something like: I presume building FreeBSD RELENG_4 world on i386 with -fomit-frame-pointer may lead to some undesired effects. But I neither found them in my (not so deep though) tests nor read info about it except GCC-info's note that you cite. 8-12% of code efficiency is not too small... Sincerely, D.Marck [DM5020, DM268-RIPE, DM3-RIPN] ------------------------------------------------------------------------ *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru *** ------------------------------------------------------------------------ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message