The kern.elf64.aslr.pie_enable and kern.elf32.aslr.pie_enable sysctls control the default setting for PIE binary address randomization, but it is possible to enable or disable ASLR on a per-process basis. Use procctl(2) to query whether ASLR is enabled.
(Note that with ASLR enabled but sysctl kern.elf64.aslr.pie_enable=0 a PIE binary will in effect have randomization disabled, and be functional with msan. This is not intended as as a user-facing control though. The user can use proccontrol(1) to disable aslr for the process.)
From LLVM 64de0064f315f57044294879d9ff4eacb454d45b
(review for approval to merge to in-tree copy of contrib/llvm-project)