From mboxrd@z Thu Jan 1 00:00:00 1970 From: Helge Deller Subject: Re: parisc: unwind tables and backtraces broken? Date: Tue, 07 Jul 2009 20:02:43 +0200 Message-ID: <4A538DC3.5070107@gmx.de> References: <20090707005018.C697F4FE0@hiauly1.hia.nrc.ca> <4A52BBE2.7020507@tausq.org> <20090707044214.GB3826@bombadil.infradead.org> <119aab440907070707u5cbf0de7j60fb80cef470f216@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: Kyle McMartin , Randolph Chung , John David Anglin , linux-parisc@vger.kernel.org, dave.anglin@nrc-cnrc.gc.ca To: Carlos O'Donell Return-path: In-Reply-To: <119aab440907070707u5cbf0de7j60fb80cef470f216@mail.gmail.com> List-ID: List-Id: linux-parisc.vger.kernel.org On 07/07/2009 04:07 PM, Carlos O'Donell wrote: > On Tue, Jul 7, 2009 at 12:42 AM, Kyle McMartin wrote: >> indeed, it very briefly had a dwarf unwinder, but linus turned it off >> again because it turned out to generate worse backtraces than just >> chunking through stack frames with frame pointers enabled did. although, >> there is talk of it growing one again now. > > It will definitely need to grow a dwarf2 unwinder. > > Any sane ABI should drop the hard frame pointer requirement in order > to get better code generation. For example on ARM under the EABI there > is no hard fp, you get that register back for other uses and it > simplifies prologue and epilogues. If you need an offset from the fp > the compiler synthesizes it for you, and reuses it appropriately after > the use is dead. > > I thought bfd, and therefore readelf and objdump could read parisc > unwind info, if so, then what do those tools say about this broken > unwind info? Any hint what I should do to give you the input you need? Helge