From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14983 invoked by alias); 5 Nov 2004 20:41:09 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 14974 invoked from network); 5 Nov 2004 20:41:07 -0000 Received: from unknown (HELO nevyn.them.org) (66.93.172.17) by sourceware.org with SMTP; 5 Nov 2004 20:41:07 -0000 Received: from drow by nevyn.them.org with local (Exim 4.34 #1 (Debian)) id 1CQAtK-0006AA-Fi; Fri, 05 Nov 2004 15:41:02 -0500 Date: Fri, 05 Nov 2004 20:41:00 -0000 From: Daniel Jacobowitz To: Mark Kettenis Cc: cagney@gnu.org, gdb-patches@sources.redhat.com Subject: Re: [COMMIT] Fix decoding CIE's in DWARF frame info Message-ID: <20041105204101.GA23606@nevyn.them.org> Mail-Followup-To: Mark Kettenis , cagney@gnu.org, gdb-patches@sources.redhat.com References: <200411051543.iA5Fh1nK020633@juw15.nfra.nl> <418BB19C.7000100@gnu.org> <200411051853.iA5IrpfP014435@elgar.sibelius.xs4all.nl> <20041105191217.GA23973@nevyn.them.org> <200411052036.iA5KaHFK014692@elgar.sibelius.xs4all.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200411052036.iA5KaHFK014692@elgar.sibelius.xs4all.nl> User-Agent: Mutt/1.5.5.1+cvs20040105i X-SW-Source: 2004-11/txt/msg00092.txt.bz2 On Fri, Nov 05, 2004 at 09:36:17PM +0100, Mark Kettenis wrote: > Date: Fri, 5 Nov 2004 14:12:17 -0500 > From: Daniel Jacobowitz > > On Fri, Nov 05, 2004 at 07:53:51PM +0100, Mark Kettenis wrote: > > Date: Fri, 05 Nov 2004 12:00:12 -0500 > > From: Andrew Cagney > > > > Mark Kettenis wrote: > > > The old code didn't take into account that the encoding used to > > > specify the personality routine in the augmentation could be > > > DW_PE_EH_aligned. > > > > > > Fixed by the attach patch. > > > > > > Committed to mainline. I'll commit this to the branch later today. > > > > How are you testing this? I'm seeing: > > > > dwarf2-frame.c:1083: internal-error: Unsupported encoding: DW_EH_PE_indirect > > > > If your toolchain really generates DW_EH_PE_indirect, it's a different > > problem; I don't know how to properly support this :-(. > > I do know that some GCC toolchains emit DW_EH_PE_indirect - I ran into > it yesterday on PowerPC. It's exactly what it says; after applying > whatever other encoding (pcrel, etc), dereference the result. Adding > this to read_encoded_value should be pretty straightforward. > > I don't think so. We read the encoded pointers when we load the > executable in GDB. But if the value of these encoded pointers is > known at that point, why doesn't the (static) linker resolve things > instead of having us goe through the indirection process? Because this is used, as far as I know, only for PIC code in shared libraries (which we only load after they've been dynamically relocated). DW_EH_PE_indirect is used so that symbols which will need a runtime RELATIVE relocation live in the data segment, instead of the with the rest of the exception data, which could otherwise be read-only. It's true that in general we'd have to delay the read until it was used, but I think it'll work OK to read it right away for all cases I know of. But I don't have a test case, so I'll just save this thought for later. -- Daniel Jacobowitz