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Re: gdb/1383: Enhancement: support open watcom
- From: Bart Oldeman <bartoldeman at users dot sourceforge dot net>
- To: nobody at sources dot redhat dot com
- Cc: gdb-prs at sources dot redhat dot com,
- Date: 8 Nov 2004 04:48:00 -0000
- Subject: Re: gdb/1383: Enhancement: support open watcom
- Reply-to: Bart Oldeman <bartoldeman at users dot sourceforge dot net>
The following reply was made to PR gdb/1383; it has been noted by GNATS.
From: Bart Oldeman <bartoldeman@users.sourceforge.net>
To: gdb-gnats@sources.redhat.com
Cc:
Subject: Re: gdb/1383: Enhancement: support open watcom
Date: Mon, 8 Nov 2004 17:47:04 +1300 (NZDT)
Open Watcom generates DWARF-2
The generated DWARF is incompatible with GDB in various ways:
a) no alignment in .debug_aranges
there needs to be a 4 byte alignment on i386; there was no
alignment. This is a violation of the spec.
b) all addresses are 0 based (e.g. for ELF, Watcom stores 0x100
where GCC stores 0x8048200). GDB assumes that they are
absolute as far as I could see. This isn't really a violation
but an "implementation detail" (according to Michael Eager)
c) A missing DW_AT_frame_base. A spec violation.
We're fixing at least a) and c) on the Watcom side now. I'm not so sure
about b). For ELF it is clear that "what others do is probably best".
For PE it's somewhat more difficult. The debugger would probably have to
compare a DWARF address with an address in the executable header and
calculate a base from this.
Bart