[llvm-dev] [RFC] AAP Backend

Ed Jones via llvm-dev llvm-dev at lists.llvm.org
Thu Aug 18 07:16:13 PDT 2016

On 18/08/16 13:57, Renato Golin wrote:
> So, the discussion that has to happen before is: are those two
> differences deal breakers for your target?
> If the AAP back-end can't work without those two features, and they
> prove hard to adapt, it may be hard to get the AAP in-tree.
> But I don't think that will be the case. The CHERI back-end also has
> fat pointers by default, and they were encouraged to merge their
> changes, which is at least one similarity with your own back-end.
> My personal take is that it would be good to allow non-integer
> pointers in IR, but this may also prove complicated for the
> middle-end. Time will tell.
> Submitting those two patches, or at least their RFCs, would be a good
> way to make sure there are no contentious issues with the rest of the
> code.

I don't think they're absolutely necessary. Also when I say that we have
large pointers, it is only when emitting code. Pointers are 16-bits
internally, but we use a 32-bit ELF with the upper 16-bit used to store
flags such as the address space.

The other generic change is not absolutely necessary, and we could avoid
it by changing the calling convention.

> I don't think that's a good idea. The simulator should be a separate
> project altogether, on its own GitHub repository, using the LLVM
> libraries as such.

Okay, this sounds sensible. We'll cross that bridge when we come to it.

Thank you,
Ed Jones

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