Saving to 32 bits of GPRs in signal context

[Hiroyuki Machida]

Hi Steve,

2007/5/30, Steve Munroe <sjmunroe at us.ibm.com>:
>
> Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote on 05/29/2007
> 04:44:15 PM:
  :
  :
> > >
> > > Also if you want to debug this code (see long long variables correctly
> from
> > > GDB or even see the upper 32-bits of GPRs) you will need an ABI change
> so
> > > that GDB/DWARF knows what to do.

As already mentioned, ABI (calling convetion and relocations) wont't change,
so there's no exteion to DWARF required,  I think. Do you have any concern ?

> >
> > I personally don't care about gdb seeing those or anything like that,
> > those would be strictly local asm optimisations, at least that's my
> > point of view on the matter.
> >
> Well others do. If gcc supports code gen for this they will expect GDB
> support.

Even now,  gcc -m32 -mpowerpc64  produces 64 bit insns.
I've cheked with gcc version 4.1.1 20070105 (Red Hat 4.1.1-51).
But in most case, developers would use these options to some
specific files which are critical to performance.

I think GDB support is not critical, but would be expected.

---
Hiroyuki Machida