coverage: Re-enable UnreachablePropagation for coverage builds
#122860
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rustbot has assigned @petrochenkov. Use |
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Some changes occurred to MIR optimizations cc @rust-lang/wg-mir-opt |
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This was referenced Mar 22, 2024
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| }) | ||
| .filter({ | ||
| // We only need one arbitrary instance per definition. | ||
| let mut seen = FxHashSet::default(); |
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No need to create an inner scope for this. A function-level binding is good enough, it's moved into the closure anyway.
| @@ -354,78 +346,94 @@ fn add_unused_functions(cx: &CodegenCx<'_, '_>) { | |||
| assert!(cx.codegen_unit.is_code_coverage_dead_code_cgu()); | |||
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| let tcx = cx.tcx; | |||
| let usage = prepare_usage_sets(tcx); | |||
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| let is_unused_fn = |def_id: &&LocalDefId| -> bool { | |||
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The closure should take by value, and let the caller dereference.
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@bors try @rust-timer queue |
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Awaiting bors try build completion. @rustbot label: +S-waiting-on-perf |
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coverage: Re-enable `UnreachablePropagation` for coverage builds This is a sequence of 3 related changes: - Clean up the existing code that scans for unused functions - Detect functions that were instrumented for coverage, but have had all their coverage statements removed by later MIR transforms (e.g. `UnreachablePropagation`) - Re-enable `UnreachablePropagation` in coverage builds Because we now detect functions that have lost their coverage statements, and treat them as unused, we don't need to worry about `UnreachablePropagation` removing all of those statements. This is demonstrated by `tests/coverage/unreachable.rs`. Fixes rust-lang#116171.
If a function was instrumented for coverage, but all of its coverage statements have been removed by later MIR transforms, it should be treated as "unused" even if the compiler generates an unreachable stub for it.
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Addressed feedback (diff). I think I still prefer the way it was, but 🤷♂️. |
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I'm not 100% sure, but I don't think we have any benchmarks that actually enable coverage. |
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Thanks. |
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…llaumeGomez Rollup of 6 pull requests Successful merges: - rust-lang#121843 (Implement `-L KIND=`@RUSTC_BUILTIN/...`)` - rust-lang#122860 (coverage: Re-enable `UnreachablePropagation` for coverage builds) - rust-lang#123021 (Make `TyCtxt::coroutine_layout` take coroutine's kind parameter) - rust-lang#123024 (CFI: Enable KCFI testing of run-pass tests) - rust-lang#123083 (lib: fix some unnecessary_cast clippy lint) - rust-lang#123116 (rustdoc: Swap fields and variant documentations) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#122860 - Zalathar:unused, r=cjgillot coverage: Re-enable `UnreachablePropagation` for coverage builds This is a sequence of 3 related changes: - Clean up the existing code that scans for unused functions - Detect functions that were instrumented for coverage, but have had all their coverage statements removed by later MIR transforms (e.g. `UnreachablePropagation`) - Re-enable `UnreachablePropagation` in coverage builds Because we now detect functions that have lost their coverage statements, and treat them as unused, we don't need to worry about `UnreachablePropagation` removing all of those statements. This is demonstrated by `tests/coverage/unreachable.rs`. Fixes rust-lang#116171.
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This is a sequence of 3 related changes:
UnreachablePropagation)UnreachablePropagationin coverage buildsBecause we now detect functions that have lost their coverage statements, and treat them as unused, we don't need to worry about
UnreachablePropagationremoving all of those statements. This is demonstrated bytests/coverage/unreachable.rs.Fixes #116171.