dwarf-2 problem on cc1

Robert Lipe robertl@sco.com
Sat Jun 12 20:59:00 GMT 1999


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[ Damned inconsistencies ] 

Date: Sat, 12 Jun 1999 20:00:46 -0500
From: Robert Lipe <robertl@sco.com>
To: egcs@egcs.cygnus.com
Cc: gdb@gdb.cygnus.com
Subject: dwarf-2 problem on cc1
Message-ID: <19990612200046.A22605@rjlhome.sco.com>
Mime-Version: 1.0
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[ Two disparate groups copied; please drop the other as appropriate. ] 

I can't tell if this is an GCC problem or a GDB problem.   I'm inclined
to think it's EGCS becuase SCO's 'debug' complains about the binary, too.

I'm looking at GCC 2.95 (i686-UnixWare7.1.0-sysv5) with GDB 4.18.  Small
binaries work OK.   Big ones fail and I need help understanding why.

The easiest way to see this fail is in GCC itself after a full three-stage:

(robertl) rjludi:/home3/negcs/gcc
$ gdb ./cc1
GNU gdb 4.18
Copyright 1998 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-UnixWare7.1.0-sysv5"...

Dwarf Error: bad offset (0x93000200) in compilation unit header (offset 0x2320b5 + 6).

.gdbinit:8: Error in sourced command file:


Now, if I use GDB on GDB to debug cc1 and set breakpoints on this error,
I can see that it's not anything as "obvious" as a sign extension
problem.

(top-gdb) print /x cu_header
$2 = {length = 0x28000000, version = 0x2, abbrev_offset = 0x93000200, 
  addr_size = 0xce}

That's a pretty bogus looking length.




If I feed that same binary to the SCO dwarf-2 debugger, it complains in 
a different way:

$ debug cc1
Error: Unrecognized debugging information at offset 0x2320b5
Error: Inconsistent state in function Dwarf2build::get_syminfo at line 788
Error: Unrecognized debugging information at offset 0x2320b5
Error: Inconsistent state in function Dwarf2build::get_syminfo at line 788
Error: Unrecognized debugging information at offset 0x2320b5
Error: Inconsistent state in function Dwarf2build::get_syminfo at line 788
Error: Unrecognized debugging information at offset 0x2320b5
Error: Inconsistent state in function Dwarf2build::get_syminfo at line 788
Error: Unrecognized debugging information at offset 0x2320b5
Error: Inconsistent state in function Dwarf2build::get_syminfo at line 788
Error: Unimplemented DWARFII location operator at offset 0x5237: DW_OP_fbreg
Error: Unimplemented DWARFII debugging information entry in section .debug_info
New program cc1 (process p1) created


It's not strictly size related.   I can invoke gdb on cc1plus and it's 
fine.   gdb on several of the gen* programs and it's fine.   but the inability
to debug cc1 worries me.

Any ideas?

RJL



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