110 lines
2.0 KiB
Rust
110 lines
2.0 KiB
Rust
//@ only-x86_64
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//@ run-pass
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//@ needs-asm-support
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#![deny(unreachable_code)]
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#![feature(asm_goto)]
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use std::arch::asm;
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fn goto_fallthough() {
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unsafe {
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asm!(
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"/* {} */",
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label {
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unreachable!();
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}
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)
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}
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}
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fn goto_jump() {
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unsafe {
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let mut value = false;
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asm!(
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"jmp {}",
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label {
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value = true;
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}
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);
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assert!(value);
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}
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}
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// asm goto with outputs cause miscompilation in LLVM. UB can be triggered
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// when outputs are used inside the label block when optimisation is enabled.
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// See: https://github.com/llvm/llvm-project/issues/74483
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/*
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fn goto_out_fallthrough() {
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unsafe {
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let mut out: usize;
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asm!(
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"lea {}, [{} + 1]",
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"/* {} */",
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out(reg) out,
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in(reg) 0x12345678usize,
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label {
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unreachable!();
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}
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);
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assert_eq!(out, 0x12345679);
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}
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}
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fn goto_out_jump() {
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unsafe {
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let mut value = false;
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let mut out: usize;
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asm!(
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"lea {}, [{} + 1]",
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"jmp {}",
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out(reg) out,
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in(reg) 0x12345678usize,
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label {
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value = true;
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assert_eq!(out, 0x12345679);
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}
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);
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assert!(value);
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}
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}
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*/
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fn goto_noreturn() {
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unsafe {
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let a;
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asm!(
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"jmp {}",
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label {
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a = 1;
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},
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options(noreturn)
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);
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assert_eq!(a, 1);
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}
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}
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#[warn(unreachable_code)]
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fn goto_noreturn_diverge() {
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unsafe {
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asm!(
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"jmp {}",
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label {
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return;
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},
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options(noreturn)
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);
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unreachable!();
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//~^ WARN unreachable statement
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}
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}
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fn main() {
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goto_fallthough();
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goto_jump();
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// goto_out_fallthrough();
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// goto_out_jump();
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goto_noreturn();
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goto_noreturn_diverge();
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}
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