DEC-SRC-Modula-3-3.5.1-m3gdb-distribution

There are two GNU debugger versions that have been extended to 
understand Modula-3 source and expressions: The first one is
distributed by DEC SRC and is based on gdb 4.11. Some things
are still missing in this version, but it has been reported to be
quite stable and usable. Most work has been done by Bill Kalsow,
I think.

The other debugger package is based on a development snapshot
from GNU gdb 4.13. Oliver Meyer (from RWTH Aachen, if I remember
correctly) has invested a lot of work to enhance the debugger to
understand complex expressions, types and modules. He also
integrated support for Modula-2 (Sun compiler), and there are
Fortran specific sources in his package. His debugger has been
thought of as a big step towards a final solution for Modula-3
(or so I heard ;-).

Since none of the debuggers supported FreeBSD as a target, I
decided it would be easier to integrate the changes for Modula-3
into the FreeBSD debugger sources than vice versa. So now
there are two new sudirectories under /usr/src/gnu/usr.bin/gdb:
m3gdb (the original DEC version) and m23gdb (the version extended
by Oliver Meyer). Both versions compile and link (with some warnings),
but - alas - both do not work as expected. I invested most time in
getting m23gdb up, but there still is a major problem with the
construction or with the handling of the symbol-tables: The
debugger cannot find any local symbols. There are probably many
other bugs in the result of my effort to integrate the Modula-3
extensions, but I deemed the ability to inspect values of variables 
and functions to be the most basic and needed one. I am sorry that I
couldn't achieve a more satisfactory result, but the time I can 
spent on this work is limited, and probably people with a better
understanding of gdb will find the bugs faster than I ever could
dream of.

Perhaps some day Modula-3 support will even be integrated into the
standard system debugger of FreeBSD. For the time being I thought
that the current state of the port might be interesting for those
considering to use Modula-3, and so I packed up the sources as they 
are.

I don't think I will be able to work on this port during the next
weeks, but I would be very interested in getting every patch that
improves the debugger.

Please send flames to /dev/null and patches and useful comments or
hints to wagner@luthien.in-berlin.de or olaf@logware.de.

Olaf Wagner              18. April 1995

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I traced some of the bugs in the standard m3gdb distribution port, and 
now it can be used to inspect values quite satisfactoriliy. I'll leave
it as it is until I will need other features...

Olaf Wagner               2. May 1995

