| //@ compile-flags: -C no-prepopulate-passes -Zbranch-protection=bti |
| //@ assembly-output: emit-asm |
| //@ needs-asm-support |
| //@ only-aarch64 |
| |
| #![crate_type = "lib"] |
| #![feature(naked_functions)] |
| use std::arch::naked_asm; |
| |
| // The problem at hand: Rust has adopted a fairly strict meaning for "naked functions", |
| // meaning "no prologue whatsoever, no, really, not one instruction." |
| // Unfortunately, aarch64's "branch target identification" works via hints at landing sites. |
| // LLVM implements this via making sure of that, even for functions with the naked attribute. |
| // So, we must emit an appropriate instruction instead! |
| #[no_mangle] |
| #[naked] |
| pub unsafe extern "C" fn _hlt() -> ! { |
| // CHECK-NOT: hint #34 |
| // CHECK: hlt #0x1 |
| naked_asm!("hlt #1") |
| } |
