[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.


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