[ORC] Use after free in multi-threaded setups

[bluescarni]

LLVM versions up to and including 19RC4 have a use-after-free bug that inconsistently shows up in multi-threaded setups. The bug was diagnosed and fixed by @lhames in this commit on main:

7034ec4

Would it be possible to have this fix backported to the 19 release branch or to the first dot release of the LLVM 19 series?

[llvmbot]

@llvm/issue-subscribers-orcjit

Author: Francesco Biscani (bluescarni)

LLVM versions up to and including 19RC4 have a use-after-free bug that inconsistently shows up in multi-threaded setups. The bug was diagnosed and fixed by @lhames in this commit on ``main``:

7034ec4

Would it be possible to have this fix backported to the 19 release branch or to the first dot release of the LLVM 19 series?

[lhames]

This seems like a reasonable bug-fix for the release.

/cherry-pick 7034ec4