[Dwarf-Discuss] modeling different address spaces

[Metzger, Markus T]

Hello Todd,

> They use DW_AT_address_class with a CUDA-specific enum of address spaces,
> with
> values for things like: global memory, shared memory, const memory, etc.  They
> don't attach these attributes to subroutines, because all the code on that
> architecture is in a single "code" memory.  They do attach them to pointer
> types, as the DWARF spec describes.  They also attach them to variables,
> formals, etc.  That's a vendor extension (which I'd forgotten until I looked it
> up again in the DWARF spec).  But an obvious one.  We might want to formalize it
> at some point.
> 
> Anyway, these are the sorts of things we see:
> 
>    DW_TAG_pointer_type
>       DW_AT_type          : ...
>       DW_AT_address_class : ptxGenericStorage
> 
>    DW_TAG_variable
>       DW_AT_name          : myConstant
>       DW_AT_type          : ...
>       DW_AT_location      : ...
>       DW_AT_address_class : ptxConstStorage
> 
>    DW_TAG_variable
>       DW_AT_abstract_origin : ...
>       DW_AT_location        : ...
>       DW_AT_address_class   : ptxLocalStorage
> 
> I don't know your architecture, but I'd expect something similar to work for any
> GPU with heterogeneous memories.

That looks good to me.  And I agree that it would be very nice if the extension to
attach this attribute to variables were formalized.

Thanks,
Markus.
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