tests/assembly/x86_64-naked-fn-no-cet-prolog.rs

   1 // compile-flags: -C no-prepopulate-passes -Zcf-protection=full
   2 // assembly-output: emit-asm
   3 // needs-asm-support
   4 // only-x86_64
   5
   6 #![crate_type = "lib"]
   7 #![feature(naked_functions)]
   8 use std::arch::asm;
   9
  10 // The problem at hand: Rust has adopted a fairly strict meaning for "naked functions",
  11 // meaning "no prologue whatsoever, no, really, not one instruction."
  12 // Unfortunately, x86's control-flow enforcement, specifically indirect branch protection,
  13 // works by using an instruction for each possible landing site,
  14 // and LLVM implements this via making sure of that.
  15 #[no_mangle]
  16 #[naked]
  17 pub unsafe extern "sysv64" fn will_halt() -> ! {
  18     // CHECK-NOT: endbr{{32|64}}
  19     // CHECK: hlt
  20     asm!("hlt", options(noreturn))
  21 }
  22
  23 // what about aarch64?
  24 // "branch-protection"=false