[llvm] [BOLT][AArch64] Fix PREL Relocs on RHEL8 (PR #144505)

[Paschalis Mpeis via llvm-commits]

paschalis-mpeis wrote:


> This does highlight a potential problem with these tests that you may be able to solve by requiring an lld built from source at the same time as BOLT or setting a REQUIRES minimum lld version. For example lets say a new lld version does some additional optimisations, under a new flag not accepted by older lld versions so it can't be used to turn them off; then you may find that there's no way to avoid different linker output from affecting your tests.

@smithp35:  Absolutely, it seems that's why the test is flaky.

We invoke the linker via the `%clang` driver, which comes from the build dir. If lld isn't there, clang would pick whatever is on the system. However, lld is a required project for bolt tests, so I'm not sure what happens on RHEL8, and I don't have easy access to check.

Maybe this is solved if we introduce `%lld` to the lit config, coming from build dir? That is as an alternative of skipping affected tests with REQUIRES.

https://github.com/llvm/llvm-project/pull/144505