This is the mail archive of the
gdb-prs@sources.redhat.com
mailing list for the GDB project.
Re: symtab/1333: Internal error with Dwarf2
- From: Jim Blandy <jimb at redhat dot com>
- To: jimb at redhat dot com
- Cc: gdb-prs at sources dot redhat dot com,
- Date: 15 Aug 2003 21:38:00 -0000
- Subject: Re: symtab/1333: Internal error with Dwarf2
- Reply-to: Jim Blandy <jimb at redhat dot com>
The following reply was made to PR symtab/1333; it has been noted by GNATS.
From: Jim Blandy <jimb@redhat.com>
To: gdb-gnats@sources.redhat.com
Cc:
Subject: Re: symtab/1333: Internal error with Dwarf2
Date: 15 Aug 2003 16:30:46 -0500
X-From-Line: imap Thu Aug 14 12:21:00 2003
Return-Path: <gdb-return-15151-jimb=redhat.com@sources.redhat.com>
Received: from pobox.corp.redhat.com ([unix socket])
by pobox.corp.redhat.com (Cyrus v2.1.12) with LMTP; Thu, 14 Aug 2003 10:56:13 -0400
X-Sieve: CMU Sieve 2.2
Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254])
by pobox.corp.redhat.com (8.12.8/8.12.8) with ESMTP id h7EEuDED023586
for <jimb@pobox.corp.redhat.com>; Thu, 14 Aug 2003 10:56:13 -0400
Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31])
by int-mx1.corp.redhat.com (8.11.6/8.11.6) with SMTP id h7EEuDs25957
for <jimb@redhat.com>; Thu, 14 Aug 2003 10:56:13 -0400
Received: from sources.redhat.com (sources.redhat.com [67.72.78.213])
by mx1.redhat.com (8.11.6/8.11.6) with SMTP id h7EEuCt31360
for <jimb@redhat.com>; Thu, 14 Aug 2003 10:56:12 -0400
Received: (qmail 8307 invoked by alias); 14 Aug 2003 14:56:01 -0000
Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm
Precedence: bulk
List-Unsubscribe: <mailto:gdb-unsubscribe-jimb=redhat.com@sources.redhat.com>
List-Subscribe: <mailto:gdb-subscribe@sources.redhat.com>
List-Archive: <http://sources.redhat.com/ml/gdb/>
List-Post: <mailto:gdb@sources.redhat.com>
List-Help: <mailto:gdb-help@sources.redhat.com>, <http://sources.redhat.com/ml/#faqs>
Sender: gdb-owner@sources.redhat.com
Delivered-To: mailing list gdb@sources.redhat.com
Received: (qmail 8292 invoked from network); 14 Aug 2003 14:56:00 -0000
Received: from unknown (HELO maxipes.logix.cz) (81.0.234.97)
by sources.redhat.com with SMTP; 14 Aug 2003 14:56:00 -0000
Received: from suse.cz (styx.suse.cz [213.210.157.162])
(using TLSv1 with cipher RC4-MD5 (128/128 bits))
(Client CN "Michal Ludvig", Issuer "Personal Freemail RSA 2000.8.30" (verified OK))
by maxipes.logix.cz (Postfix) with ESMTP
id 5E8B4299DF; Thu, 14 Aug 2003 16:55:59 +0200 (CEST)
Message-ID: <3F3BA318.3050305@suse.cz>
Date: Thu, 14 Aug 2003 16:56:24 +0200
From: Michal Ludvig <mludvig@suse.cz>
Organization: SuSE CR, s.r.o.
User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.5b) Gecko/20030813
X-Accept-Language: cs, cz, en
To: gdb <gdb@sources.redhat.com>
Cc: Elena Zannoni <ezannoni@redhat.com>, Daniel Jacobowitz <drow@mvista.com>
Subject: Re: Dwarf2-related Internal error
References: <3F0AD6F4.9060709@suse.cz> <3F3B6C99.6020908@suse.cz> <16187.34103.759484.814559@localhost.redhat.com> <3F3B8C04.1010309@suse.cz>
In-Reply-To: <3F3B8C04.1010309@suse.cz>
Lines: 65
Xref: zenia.home mail.gdb.outside:10405
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Michal Ludvig told me that:
> Elena Zannoni told me that:
>
>> I don't have much time to devote to this, but usually that kind of
>> error is generated by some infinite loop that gdb got itself into.
>
>
> Unlikely. The immediate problem is that the size of function's parameter
> 'xx' is too big:
>
> (top-gdb) f
> #0 read_var_value (var=0x8b35c0, frame=0x85ad98)
> at ../../gdb-head/gdb/findvar.c:397
> 397 struct type *type = SYMBOL_TYPE (var);
> (top-gdb) p *var->type
> $2 = {pointer_type = 0x0, reference_type = 0x0, chain = 0x89fc00,
> instance_flags = 0, length = 4294967292, main_type = 0x89fc28}
> (top-gdb) p (int)4294967292
> $3 = -4
> (top-gdb)
>
> Very likely it was ment to be -4 because something somewhere in the
> debug info was wrongly interpreted.
OK, I have found the problem. The type of the parameter 'xx' is an array
with unspecified size. Lower bound is set to '1' for Fortran and since
there is no upper bound specified, it's set to '-1' by default.
3097 else if (attr->form == DW_FORM_block1)
3098 {
3099 /* GCC encodes arrays with unspecified or dynamic length
3100 with a DW_FORM_block1 attribute.
3101 FIXME: GDB does not yet know how to handle dynamic
3102 arrays properly, treat them as arrays with unspecified
3103 length for now. */
3104 high = -1;
3105 }
Later, when the actual size of the array type is computed, it takes the
size of the main type (real, size=4) and multiplies it by
(high-low+1=-1) leading to -4 which is quite a big number when converted
to unsigned.
Now how to solve it. For now I did
length for now. */
high = -1;
+ if (cu_language == language_fortran)
+ high = 0;
}
which at least prevents GDB from crashing. IMHO it achieves the same
behaviour as for other languages, where low=0, high=-1 and so the size
of the array results to 0. In fortran low=1, so with high=0 the size
will become 0 as well.
Would this be an acceptable solution? Any comments?
Michal Ludvig
--
* SuSE CR, s.r.o * mludvig@suse.cz
* (+420) 296.545.373 * http://www.suse.cz