From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4023 invoked by alias); 8 Oct 2012 20:38:29 -0000 Received: (qmail 3853 invoked by uid 22791); 8 Oct 2012 20:38:28 -0000 X-SWARE-Spam-Status: No, hits=-3.8 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,KHOP_RCVD_TRUST,KHOP_THREADED,RCVD_IN_DNSWL_LOW,RCVD_IN_HOSTKARMA_YE X-Spam-Check-By: sourceware.org Received: from mail-oa0-f41.google.com (HELO mail-oa0-f41.google.com) (209.85.219.41) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 08 Oct 2012 20:38:22 +0000 Received: by mail-oa0-f41.google.com with SMTP id k14so670464oag.0 for ; Mon, 08 Oct 2012 13:38:21 -0700 (PDT) MIME-Version: 1.0 Received: by 10.182.185.12 with SMTP id ey12mr626696obc.7.1349728701655; Mon, 08 Oct 2012 13:38:21 -0700 (PDT) Received: by 10.76.144.229 with HTTP; Mon, 8 Oct 2012 13:38:21 -0700 (PDT) In-Reply-To: <201210082022.q98KM82d014759@glazunov.sibelius.xs4all.nl> References: <20121003154712.GH3028@adacore.com> <201210040657.q946vJlc006566@glazunov.sibelius.xs4all.nl> <201210081948.q98Jm3D7020175@glazunov.sibelius.xs4all.nl> <201210082022.q98KM82d014759@glazunov.sibelius.xs4all.nl> Date: Mon, 08 Oct 2012 20:38:00 -0000 Message-ID: Subject: Re: PING: PATCH: PR backtrace/14646: [x32] backtrace doesn't work From: "H.J. Lu" To: Mark Kettenis Cc: gdb-patches@sourceware.org Content-Type: text/plain; charset=ISO-8859-1 X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2012-10/txt/msg00140.txt.bz2 On Mon, Oct 8, 2012 at 1:22 PM, Mark Kettenis wrote: >> Date: Mon, 8 Oct 2012 13:04:03 -0700 >> From: "H.J. Lu" >> >> On Mon, Oct 8, 2012 at 12:48 PM, Mark Kettenis wrote: >> >> Date: Thu, 4 Oct 2012 06:57:22 -0700 >> >> From: "H.J. Lu" >> >> >> >> On Wed, Oct 3, 2012 at 11:57 PM, Mark Kettenis wrote: >> >> > >> >> > Perhaps the user-regs.c mechanism can be used to establish eip -> pc >> >> > and esp -> sp mappings? >> >> >> >> It doesn't help as long as gdbarch_pc_regnum/gdbarch_sp_regnum >> >> are used for both frame pc/sp value and unwind pc/sp value. For x32, >> >> we want eip/esp for frame pc/sp value and rip/rsp for unwind pc/sp >> >> value. >> > >> > That probably means we need to set gdbarch_pc_regnum (and >> > gdbarch_sp_regnum) to -1 for x32. >> >> We can't set gdbarch_pc_regnum/gdbarch_sp_regnum to -1: >> >> >> GNU gdb (GDB) 7.5.50.20121008-cvs >> Copyright (C) 2012 Free Software Foundation, Inc. >> License GPLv3+: GNU GPL version 3 or later >> This is free software: you are free to change and redistribute it. >> There is NO WARRANTY, to the extent permitted by law. Type "show copying" >> and "show warranty" for details. >> This GDB was configured as "x86_64-unknown-linux-gnu". >> For bug reporting instructions, please see: >> ... >> Reading symbols from >> /export/build/gnu/glibc-x32/build-x86_64-linux/elf/sln...done. >> (gdb) b main >> Breakpoint 1 at 0x400c20: file sln.c, line 50. >> (gdb) r >> Starting program: /export/build/gnu/glibc-x32/build-x86_64-linux/elf/sln >> /export/gnu/import/git/gdb/gdb/regcache.c:1062: internal-error: >> regcache_read_pc: Unable to find PC >> A problem internal to GDB has been detected, >> further debugging may prove unreliable. >> Quit this debugging session? (y or n) > > Well, obviously you'll need to implement gdbarch_read_pc() for this to > work. And probably a few more gdbarch methods. What do we gain by setting gdbarch_pc_regnum/gdbarch_sp_regnum to -1? PC and SP are RIP and RSP for x32. We need them for stack unwind. The only unusual part is they are 64-bit although x32 is a 32-bit environment. How about this change? diff --git a/gdb/features/i386/x32-core.xml b/gdb/features/i386/x32-core.xml index 1e41417..392ce24 100644 --- a/gdb/features/i386/x32-core.xml +++ b/gdb/features/i386/x32-core.xml @@ -34,7 +34,7 @@ - + @@ -44,7 +44,7 @@ - + -- H.J.