[compiler-rt] [sanitizer-common][Darwin] Improve mach_vm_region_recurse error handling (PR #158670)

[Mariusz Borsa via llvm-commits]

wrotki wrote:

Yeah OK, let's go with it. This function actually returns early in the happy case, and continues until exhausting all possibilities when it fails, so handling positive case on top is actually in line with 'early returns' principle.

https://github.com/llvm/llvm-project/pull/158670