[geoffk@cygnus.com: GCC testing failed with your patch.]
Jason Merrill
jason@cygnus.com
Thu Mar 23 18:19:00 GMT 2000
>>>>> Geoff Keating <geoffk@cygnus.com> writes:
> I know this is bad. There seems to be no way around it. It's why the
> PowerPC DWARF frame information uses negative offsets; it was done
> that way in the first cut and then people started shipping it on CDs
> and now we're stuck.
Note that I no longer think this is a bug; the rs6000, like the SPARC,
indeed does save some registers into the caller's frame, for which negative
offsets make sense. I cheated on the SPARC by creating a window_save
instruction rather than introduce negative offsets at that point.
> There is one kind of change you _can_ make: if all you do is change
> the behaviour in a case that never occurred before, and if the change
> of behaviour occurs on a new platform that doesn't have compatibility
> issues (eg. because you're only now implementing DWARF support on that
> platform), then that's OK.
The frame.c change that I made for the ARM fits this description.
Jason
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