[llvm-branch-commits] compiler-rt: Introduce runtime functions for emulated PAC. (PR #133530)

[Kristof Beyls via llvm-branch-commits]

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@@ -0,0 +1,7343 @@
+/*
+ * xxHash - Extremely Fast Hash algorithm
+ * Header File
+ * Copyright (C) 2012-2023 Yann Collet
+ *
+ * BSD 2-Clause License (https://www.opensource.org/licenses/bsd-license.php)
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kbeyls wrote:

This is a license different from Apache-2.0 WITH LLVM-exception.
Therefore, the process described at https://llvm.org/docs/DeveloperPolicy.html#copyright-license-and-patents should be followed to check whether this is acceptable in this specific case.

That being said, xxhash is already present under [llvm/lib/Support/xxhash.cpp](https://github.com/llvm/llvm-project/blob/21eeca3db0341fef4ab4a6464ffe38b2eba5810c/llvm/lib/Support/xxhash.cpp#L163), as you pointed out in the [RFC](https://discourse.llvm.org/t/rfc-emulated-pac/85557).

Making sure we don't have multiple copies of non-Apache-2.0 WITH LLVM-exception code would be preferable. I'll tag @beanz, as he had ideas about how to better structure vendored third party code in LLVM.

I'm not sure if moving non-Apache-2.0 WITH LLVM-exception licensed code to a run-time library (for the first time?) triggers new concerns.

I'll note that other hashing algorithms, such as [Blake3](https://github.com/llvm/llvm-project/blob/21eeca3db0341fef4ab4a6464ffe38b2eba5810c/llvm/include/llvm/Support/BLAKE3.h#L1) and [SipHash](https://github.com/llvm/llvm-project/blob/21eeca3db0341fef4ab4a6464ffe38b2eba5810c/llvm/lib/Support/SipHash.cpp#L1), which are available under the Apache-2.0 WITH LLVM-exception, are also already present in the LLVM Support library.
Would one of these preferably-licensed hashing algorithms be a good fit for the hashing functionality needed for this use case?



https://github.com/llvm/llvm-project/pull/133530