[llvm] [Exegesis] Do not assume the size and layout of the assembled snippet (PR #79636)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 approved this pull request.

One nit. Otherwise LGTM.

Thanks for fixing this. Is it possible to have a test in-tree for this or is the object file code for that downstream as well? It would be nice to have a test if possible. I mainly implemented this the way I did as I wanted to avoid the search (which I guess isn't actually that expensive) and figured exegesis de-facto only supports ELF, so this should be fine (didn't test any different object file formats though).

https://github.com/llvm/llvm-project/pull/79636