[Dwarf-Discuss] How best to represent multiple programs in a single file...

Michael Eager eager@eagercon.com
Tue Jan 4 21:19:06 GMT 2011

Relph, Richard wrote:
>> You do need to have DWARF which describes each
>> kernel separately.
> This is the conclusion I've reached.
>> This "kernel" organization looks to me a lot like
>> overlays.  I'm not exactly sure how other compilers
>> have handled this in ELF/DWARF.
> Oh my... Overlays... I'd completely forgotten that term... But that you mentioned it and that I recognized it shows something about our age, doesn't it... ;-)
> But you're right, this is very much like the old MS-DOS (or was it CP/M?) style overlays of too many years ago. A program counter address isn't enough information alone to figure out a source file line, you need to know which 'overlay' - or kernel - is currently loaded.

Actually, I was working with a DSP not long ago
which had a very involved overlay structure, where
applications were loaded over each other in memory.
And overlays predate CP/M or MS/DOS by quite a while.

Binutils has support for overlays, although I
can't say that I recall much about the details.

Michael Eager	 eager at eagercon.com
1960 Park Blvd., Palo Alto, CA 94306  650-325-8077

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