[Dwarf-discuss] Constant expressions in locations lists

[Cary Coutant]

David Anderson wrote:

> History note:  We really intended the OP evaluation
> stack to have simply 'address size integers'
> and avoid such a 'type' system entirely. Even avoiding signed/ 
> unsigned issues (as that's not a  problem
> with twos-complement). Not as an oversight, but as a design decision.
>
> Whether that simple address-size-integer
> value stack  is still sufficient is open to discussion, but
> any type system introduces all the 'conversion' issues.

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.

-cary