[Dwarf-Discuss] PROPOSAL: Constant expressions in location lists

[Michael Eager]

Chris Quenelle wrote:

> Say you have some large and complex C++ class and a single variable
> of that type.  Now let's say the optimizer has placed one tiny field
> of a deeply nested inner member of that class into a register.
> The only die is for the top-level variable.  How should the compiler
> record that one tiny part of the overall class is now in a register?

Unless I've misunderstood you, DWARF can describe this currently.
The location list for the member points to the register and gives
the scope where this is valid.

I'm not sure what you mean by having only the DIE for the "top-level
variable".  If you mean that the DWARF only contains a DW_TAG_class_type
without any of the specification for the members, then this would not
be well formed.

-- 
Michael Eager	 eager at eagercon.com
1960 Park Blvd., Palo Alto, CA 94306  650-325-8077