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