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LL| |#![feature(core_intrinsics, 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| |}
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