[clang] [compiler-rt] [llvm] [DRAFT][memprof][darwin] Support memprof on Darwin platform and add binary access profile (PR #142884)

[Snehasish Kumar via llvm-commits]

snehasish wrote:

> > Can you share the improvement in startup time observed on MachO? I can reach out to the Android toolchain team to gauge interest.
> 
> @snehasish thanks!
> 
> The improvement in startup performance we observed for iOS apps (MachO) are,
> 
> * socialApp1: for cold starts, we reduced 80ms (3%) of the entire app startup time (time to network content) on average; 270ms (6%) reduction p95. From another perspective, we reduced 5% of the total major page faults for the entire app startup phase.
> * socialApp2:  for cold starts, we reduced 54ms from app startup on average, which is around 12% of the app's premain startup time.

Great. For my understanding, the baseline app includes some form of PGO e.g. temporal profiling? These numbers are *purely* from static data layout on top of the baseline?

https://github.com/llvm/llvm-project/pull/142884