Address spaces

[Stan Shebs <stanshebs@earthlink.net>]

One of the recurring themes I'm noticing in my little bit of prototyping 
for multiprogram GDB is the need for a general concept of "address 
space". It's not quite the same as program/exec, because several 
programs could be in one address space in a non-virtual-memory system. 
It's not quite the same as process, because it applies to address lookup 
in execs prior to running any of them. It seems most like a tag glued on 
the front of a CORE_ADDR in fact (change CORE_ADDR to a struct? urgh).

Anyway, I'm just throwing this out to get people's thoughts, and see if 
I'm missing an existing basic type or bit of infrastructure that could 
serve the purpose. I don't think address space objects would be 
user-visible, nor have very many properties; I think their main purpose 
in practice will be to keep target addresses in different execs and 
processes from getting mixed up with each other.

Stan