[Dwarf-discuss] Constant expressions in locations lists

[David Anderson]

Cary Coutant wrote:
>
> Nothing in what I suggested would introduce any conversion issues -- 
> there are no implicit conversions from, say, integer to constant value 
> or register name, and there are no operators that would do any 
> conversion. The type system is just there to aid the semantic 
> description, and isn't meant to suggest any specific implementation. 
> In fact, since I'm not proposing to change the semantics -- just a way 
> of describing them -- it shouldn't have any impact at all on anyone's 
> implementation. The implementations have to deal with register names 
> and piece descriptions today, so they must already have something more 
> than just a stack of address-size-integers.
Not really.  Having implemented such a thing I'd say that's exactly what 
it is,
a stack of address size integers.  The 'plain register' case being a 
wart :-)
And a different wart for DW_OP_piece (which I never needed to implement
as the compiler involved did not produce such).

I don't understand how, if you have 'types', that one could store such 
on the
simple address-size-entry stack.  And if you had  a type for each entry,
how could DW_OP_plus do anything without some conversion.

I don't mean to be difficult, I just don't get it. Sorry.
I'm sure a complete description of what you mean by types
would answer my questions, and I'm happy to wait for such if
this notion gets general interest (and if it does not get
general interest, then it's moot). 

David Anderson