[llvm-dev] [RFC] We are running out of slots in the Attribute::AttrKind enum

[Doerfert, Johannes via llvm-dev]

We should also consider an extension. Maybe using the last bit to
indicate a lookup in a second 64-bit mask, or if the memory footprint is
not a problem, even a bitvector implementation.


There is certainly interest in adding more attributes (I can provide
references if needed), making them faster would certainly not hurt.

Cheers,
  Johannes


On 03/14, Snider, Todd via llvm-dev wrote:
> 
> I would like to add a target-dependent attribute to the LLVM IR, and the guidance in http://llvm.org/docs/HowToUseAttributes.html says that target-dependent attributes should not occupy a slot in the Attribute::AttrKind enum, but I have yet to find an attribute that is represented in the IR that does not also have a slot in the AttrKind enum.
> 
> We are limited to 63 slots in the AttrKind enum because it is represented in the bitcode with a 64-bit bitmask. There is only one free slot left and I don't want to use it for a target-dependent attribute. I had anticipated that only target-independent attributes would have analogous ATTR_KIND identifiers in the AtttrKind enum, yet the ARM-specific CMSE_NS_CALL and CMSE_NS_ENTRY occupy slots in the AttrKind enum.
> 
> Can someone point me to an example of a target-dependent attribute represented in the LLVM IR that does not occupy a slot in the AttrKind enum?
> 
> Thanks,
> 
> Todd Snider

> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev


-- 

Johannes Doerfert
Researcher

Argonne National Laboratory
Lemont, IL 60439, USA

jdoerfert at anl.gov
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 228 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20190314/42e75814/attachment.sig>