Macro nostd_panic_handler 

macro_rules! nostd_panic_handler {
    () => { ... };
}

The no_std panic handler.

Aborts through the SVM’s abort syscall, without experimental inline assembly or a compute-consuming spin loop; the runtime rolls the instruction back. With the panic-location feature it first reports the file, line, and column, and with panic-message the message. See report_panic.