[LLVMdev] Associating types directly with debug metadata?

[Pekka Nikander]

>>>> We want to avoid any Type class modification. Instead you can use pair in named metadata to match metadata with type.
>>>> 
>> 
>> I thought about that more, and I think the "right" way would be to have a syntax like
>> 
>> !21 = metadata !{ type %struct.T, metadata !11 } 
>> 
>> or perhaps
>> 
>> !21 = metadata !{ typeval %struct.T, metadata !11 }
>> 
>> to avoid the problem with the keyword 'type'.
>> 
>> Would that be worth doing?  Apparently we can fake with our need, and use a null pointer instead.  Technically, that would be wrong, but would work with the current code without any modifications:
>> 
>> !21 = metadata !{ %struct.T *null, metadata !11 }
> 
> I would recommend this approach.

But that would have a hacky feeling :-)

Anyway, I already implemented an early patch for making Types representable as Values.  For that I created a new class, TypeValue, which represents a type as a value.  An early patch for that enclosed.  Works when reading or writing textual representations; no BC representation yet.  And no test case yet.  

This works well enough for our purposes; I don't have any incentive to go further unless someone else needs a similar kind of functionality.

--Pekka

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