Ah, sorry I had found the oss implementation of libSystem_initializer before I commented here. It's just a lot of callouts to other functions that implement the actual behaviour and therefore a bit of a slog to walk through manually, so I was hoping that there was some known advice for skipping some of the work it does. I'll take a look at __libplatform_init and the rundown you wrote up about the linker and loading.

I made a "true" clone, just returning 0 immediately from main. It looks pretty much the same in terms of dyld setup time. 893μs for "Launch executable" of which 454μs is "Run static initializer" for libSystem.

Kacper, that doesn't seem to be true? At least in macOS 26.2 (25C56) I get the following error if I don't add the entitlement: Processor Trace cannot profile this process without proper permissions. Recovery Suggestion: Either: Add the 'com.apple.security.get-task-allow' entitlement to your binary entitlements file, or Make sure the build setting CODE_SIGN_INJECT_BASE_ENTITLEMENTS = YES is enabled when building with Xcode.