| LL| |#![feature(core_intrinsics)] | |
| LL| |#![feature(coverage_attribute)] | |
| LL| |//@ edition: 2021 | |
| LL| | | |
| LL| |// <https://github.com/rust-lang/rust/issues/116171> | |
| LL| |// If we instrument a function for coverage, but all of its counter-increment | |
| LL| |// statements are removed by MIR optimizations, LLVM will think it isn't | |
| LL| |// instrumented and it will disappear from coverage maps and coverage reports. | |
| LL| |// Most MIR opts won't cause this because they tend not to remove statements | |
| LL| |// from bb0, but `UnreachablePropagation` can do so if it sees that bb0 ends | |
| LL| |// with `TerminatorKind::Unreachable`. | |
| LL| | | |
| LL| |use std::hint::{black_box, unreachable_unchecked}; | |
| LL| | | |
| LL| 0|static UNREACHABLE_CLOSURE: fn() = || unsafe { unreachable_unchecked() }; | |
| LL| | | |
| LL| 0|fn unreachable_function() { | |
| LL| 0| unsafe { unreachable_unchecked() } | |
| LL| |} | |
| LL| | | |
| LL| |// Use an intrinsic to more reliably trigger unreachable-propagation. | |
| LL| 0|fn unreachable_intrinsic() { | |
| LL| 0| unsafe { std::intrinsics::unreachable() } | |
| LL| |} | |
| LL| | | |
| LL| |#[coverage(off)] | |
| LL| |fn main() { | |
| LL| | if black_box(false) { | |
| LL| | UNREACHABLE_CLOSURE(); | |
| LL| | } | |
| LL| | if black_box(false) { | |
| LL| | unreachable_function(); | |
| LL| | } | |
| LL| | if black_box(false) { | |
| LL| | unreachable_intrinsic(); | |
| LL| | } | |
| LL| |} | |