[PATCH] D92736: [lld/mac] Use xxhash instead of MD5 for computing the UUID

Tue Dec 8 14:35:17 PST 2020

clayborg added a comment.

In D92736#2439511 <https://reviews.llvm.org/D92736#2439511>, @int3 wrote:

>> So we are hashing only what ld64 is hashing? Do the RFC 4122 changes make us differ from ld64 if we don't switch hashing algorithms?
>
> No, we're hashing the object paths in the debug info too. But that should be addressed in a separate diff...

Gotcha.

> RFC 4122 has nothing to do with what gets hashed. It's merely about the format of the UUID string, which stores metadata about how the UUID was generated.

The main question is if ld64 is doing this and if we want to replicate what it does. Might be a handy option to add in case compatibility is desired: --ld64 which would enable the slower MD5 hashing of only the bits that ld64 does (and possibly other things), without this lld can pick its own hashing algorithm for speed?

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https://reviews.llvm.org/D92736