[rfc] Handle DWARF-2 value pieces residing in *parts* of a register

[Ulrich Weigand]

Tom Tromey wrote:
> >>>>> "Ulrich" == Ulrich Weigand <uweigand@de.ibm.com> writes:
> 
> Ulrich> Now, according to the DWARF-2 standard, the location of register pieces
> Ulrich> of smaller than full register size is defined by the platform ABI.
> Ulrich> For the placement of a small value in a *single* register we have a
> Ulrich> gdbarch callback (gdbarch_value_from_register); maybe we need something
> Ulrich> like that for value pieces as well.  At the very least, we ought to
> Ulrich> you the same default as default_value_from_register does: assume
> Ulrich> partial register use implies the least-significant part of the register.
> 
> Ulrich> The patch below implements this.
> 
> I think this seems reasonable.
> 
> It seems straightforward enough to add an arch method if we ever
> actually need one.  I wouldn't worry about it unless we already know of
> such a machine.

Thanks for the review.  I've checked the patch in now.

> Ulrich> 	a register, assume the least-signficant part is used.
> 
> Typo, "significant".

Fixed, thanks!

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com