Re: RFC: implement typed DWARF stack

[Tom Tromey <tromey@redhat.com>]

CCing Jakub.

Ulrich> So just to clarify: in the discussion a while back, you said:

Sorry for any confusion.  I hope this email will clear it up.

During our discussion I was convinced that DW_OP_shr should generally
use the sign of any explicit type to decide what to do (with a special
case for implicit type).  However, Jakub informed me that GCC relied on
'shr' always zero-filling, even for explicit types.  So, I changed the
code back.  What is now in the tree implements the same semantics that
GCC assumes.

Ulrich> With this latest patch, it is now definitely *not* the case that
Ulrich> DW_OP_shr and DW_OP_shra behave the same on new-style typed
Ulrich> values.  Instead, as I pointed out originally, DW_OP_shr now
Ulrich> always performs an unsigned operation, while DW_OP_shra respects
Ulrich> the value's type ...

Ulrich> Is that really what was intended?

At least the shr part is intended.  I did not consider the shra case.

Ulrich> Or should rather DW_OP_shra now also be changed (to always
Ulrich> perform a signed operation as its name suggests)?

In other words, mirror the shr special case for shra.
This makes sense to me.  Jakub, what do you think?

Tom