Overlay target stratum?

[Andrew Cagney]

Hello,

In working through target code, I keep comming across overlay stuff. 
I'm wondering if it should be moved to its own overlay-target stratum?

The user could then (at least in theory) view memory according to the 
overlay, or according to the underlying physical representation.  Also, 
totally in theory, a variant of the stratum could be implemented that 
modeled an OS's VM system!  However, that's a later bridge to cross.

The approach would be:

	target has segments (aka section_table)

	segment has
		base, length
		offset
		target (or bfd)

A memory read/write would do a virtual/physical translation using the 
segment (aka section table) and then call the underlying target's xfer 
function.

Actual code would be:

	s = this->section_by_addr (addr);
	s->target->xfer (addr - s->base + s->offset, len adjusted by s->length

The existing code already does this, but only for bfd backed segments.
(Oh, the existing code also does really evil things with the section 
table - independant targets somehow sharing a common table :-()


Thoughts?

thoughts?
Andrew