RFC: Variables in blocks of registers

[Andrew Cagney]

>> dwarf2 makes it possible to scatter a value across both memory and 
>> registers.  It's been proposed that the `struct value' be augmented with 
>> something like `struct location' that knows how to find any sub 
>> component of a value.
> 
> 
> However, right now GCC doesn't generate this.  Probably because it
> would kill us.

I'm not so sure.  In the past, GCC hasn't waited for GDB so I don't 
think that would be the reason now.

 >  If I have any mental energy left after location lists,
 > I may implement support for DW_OP_piece.

Perhaphs leave that one for someone else?


> Michael, I think the new multi-arch function is a good idea as long as
> it is a fallback from explicit debug info support, when we have such. 
> I also think it needs a better name; but I'm not quite sure what.  Hmm,
> that could be mitigated by adequate commenting.

I think it is very dangerous.  It's assuming a specific algorithm in the 
compiler.  That locks both GDB and GCC into something of a death spiral. 
  I think its far better to try and get a proper location mechanism working.

Andrew