[llvm] [BOLT] Do not fail in case of instrumentation binary without fini & fini_array & instrumentation-sleep-time>0 (PR #170086)

[Peter Waller via llvm-commits]

https://github.com/peterwaller-arm approved this pull request.

Nit: suggestion for shortening/clarity of the commit message subject:
 
> [BOLT] Allow missing DT_FINI{,_ARRAY} if instrumentation-sleep-time is used

The implementation otherwise looks reasonable to me. Please wait at least 24h to give others a chance to chime in before submitting.

I note that some well known workloads call `_exit` and can skip the exit hooks anyway, as well. So anyone working with those and using instrumentation-sleep-time would already be experiencing 'counters not flushed at the end of the workload' in the same way.

https://github.com/llvm/llvm-project/pull/170086