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Re: [RFA/RFC] dwarf2-frame read_reg
On Wed, Apr 12, 2006 at 08:17:07PM +0200, Mark Kettenis wrote:
> > Date: Tue, 11 Apr 2006 21:42:01 -0700
> > From: "Jim Blandy" <jimb@red-bean.com>
> >
> > On 4/11/06, Michael Snyder <msnyder@redhat.com> wrote:
> > > I want you guys to vett this change. I was getting wrong results
> > > on a target where sizeof (SP) != sizeof (void *). The local func
> > > read_reg was calling extract_unsigned_integer with the wrong size.
> >
> > Well, extract_typed_address requires the type of the register to be
> > some sort of pointer. read_reg is given as a callback to the Dwarf
> > expression evaluator in dwarf2expr.c, so it could be handed any
> > register at all.
> >
> > How about unpack_long (buf, register_type (gdbarch, regnum))?
> > Definitely regression-test this on several platforms...
>
> This is likely to be wrong for platforms where addresses are signed.
It shouldn't be.
unpack_long (struct type *type, const gdb_byte *valaddr)
{
...
case TYPE_CODE_PTR:
case TYPE_CODE_REF:
/* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
whether we want this to be true eventually. */
return extract_typed_address (valaddr, type);
which calls POINTER_TO_ADDRESS. And that will be the signed unpack for
MIPS, and the unsigned unpack for other targets.
So I think unpack_long is a good choice.
(I didn't realize that before. I think I have another pending patch
that this would be useful for - maybe the psaddr_t one?)
--
Daniel Jacobowitz
CodeSourcery