25 lines
782 B
Rust
25 lines
782 B
Rust
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// compile-flags: -C no-prepopulate-passes -Zcf-protection=full
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// assembly-output: emit-asm
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// needs-asm-support
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// only-x86_64
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#![crate_type = "lib"]
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#![feature(naked_functions)]
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use std::arch::asm;
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// The problem at hand: Rust has adopted a fairly strict meaning for "naked functions",
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// meaning "no prologue whatsoever, no, really, not one instruction."
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// Unfortunately, x86's control-flow enforcement, specifically indirect branch protection,
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// works by using an instruction for each possible landing site,
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// and LLVM implements this via making sure of that.
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#[no_mangle]
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#[naked]
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pub unsafe extern "sysv64" fn will_halt() -> ! {
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// CHECK-NOT: endbr{{32|64}}
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// CHECK: hlt
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asm!("hlt", options(noreturn))
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}
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// what about aarch64?
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// "branch-protection"=false
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