Intrusive GDB Symbol Lookup when debugging remotely

[David Steven Trollope <trollope@lucent.com>]

Hello!

I'm trying to determine if there exists an alternative solution, or a 
patch for the following problem, or if someone familiar with the GDB 
source can estimate how much work it would be to implement a patch. Any 
advice would be welcome and appreciated.


Configuration:

GDB running on a Sun Solaris machine.
GDBServer running on a PowerPC Linux machine
The application is running on the target in GDBServer and GDB is 
connected to the target using "target remote x.x.x.x:y"

Problem:

While the target is running, I don't think it is possible to examine the 
symbol table from within gdb without sending an interrupt signal to GDB. 
This is a problem because users (and frontends) don't seem to be able to 
look up symbols in the symbol table in GDB without interrupting the target.

In theory, it would be possible to stop the interrupt being propogated 
to the server and hence the target could remain running without 
interruption. One possible way of solving this would be to use a 
different signal as a "Non-intrusive interrupt" or "Local Interrupt". 
The symbol lookup can occur, and then gdb resumes. This would imply gdb 
would need to know if its running in "Local" or "Remote" mode to prevent 
operations trying to access the target.

An alternative mechanism could be to have a separate thread that runs 
and is signalled for non-intrusive operations.

You might ask why not just run a separate gdb instance to do this kind 
of look up? However, I am dealing with large executables where loading 
separate instances for the sake of a symbol lookup is neither efficient, 
timely or practical.

I would very much appreciate discussion on this topic with regard to 
feasibility, if its been done already or how much effort it would be to 
implement this type of functionality.

Cheers
Dave Trollope

-- 
                 Dave Trollope
              Lucent Technologies
            Tel/Fax: +1 630 713 9110
           mailto:trollope@lucent.com