Support for LLVM 16

[athas]

Oclgrind does not seem to support LLVM 16 yet. The first showstopper is that clang has changed the name of the include directory that contains opencl-c.h. From the release notes:

Clang’s resource directory path previously included the full clang version. It now includes only the major version. The new resource directory is $prefix/lib/clang/$CLANG_MAJOR_VERSION and can be queried using clang -print-resource-dir, just like before.

[jrprice]

LLVM 15 isn't yet supported either.

I have WIP changes to migrate to opaque pointers which is the main blocker on upgrading. They're almost done, so I will do my best to find some time in the near future to get that finished off so that we can support LLVM 15 and 16. Sorry for the delays!

[tkanarsky]

Any updates on this? I just tried to take a stab at porting it to LLVM 17 and quickly found myself over my head. In some cases it's pretty trivial to pull the pointee type info from e.g. the owning instr but in your business logic where we're hopping around and dereferencing things, there doesn't seem to be a good way other than keeping an out-of-band mapping from pair<address_space, Value*> -> pointee_type.

[RossComputerGuy]

This would be great since we have plans to drop LLVM 12 from Nixpkgs.

[athas]

oclgrind is slated to be removed from Nixpkgs: NixOS/nixpkgs#440273

I'd take a stab at upgrading oclgrind myself, but I am unfamiliar with LLVM's API, and it sounds like the problem is greater than tweaking include paths.

Since I use oclgrind frequently in my own work, I'll probably produce a Nix derivation that uses an older LLVM.

[jrprice]

LLVM 16 is now supported (with just one regression that I'm aware of). Apologies for taking so long to get to this. I do read all of these comments though, and they're very useful for knowing what people need.

I realize that LLVM 16 is now too old for most people and package managers. I'm working on continuing to push support forwards for LLVM 17+. I'll close this issue now, and I've opened issues for supporting LLVM 19, 20, and 21 that people can subscribe to track ongoing progress.

[athas]

Thank you for your continued maintenance of oclgrind! I assume that it is no longer an important part of your own toolbox, but there is definitely research I would never have been able to carry out if I did not have oclgrind. I think it's in the acknowledgements section of most of my papers.