diff --git a/compiler/rustc_mir_transform/src/coverage/spans.rs b/compiler/rustc_mir_transform/src/coverage/spans.rs index 9cda71cdd0770..cc8ce6d6e8f4d 100644 --- a/compiler/rustc_mir_transform/src/coverage/spans.rs +++ b/compiler/rustc_mir_transform/src/coverage/spans.rs @@ -24,8 +24,7 @@ pub(super) fn extract_refined_covspans( from_mir::mir_to_initial_sorted_coverage_spans(mir_body, hir_info, basic_coverage_blocks); for bucket in sorted_span_buckets { let refined_spans = SpansRefiner::refine_sorted_spans(bucket); - code_mappings.extend(refined_spans.into_iter().map(|covspan| { - let RefinedCovspan { span, bcb, is_hole: _ } = covspan; + code_mappings.extend(refined_spans.into_iter().map(|RefinedCovspan { span, bcb }| { // Each span produced by the refiner represents an ordinary code region. mappings::CodeMapping { span, bcb } })); @@ -36,24 +35,16 @@ pub(super) fn extract_refined_covspans( struct CurrCovspan { span: Span, bcb: BasicCoverageBlock, - is_hole: bool, } impl CurrCovspan { - fn new(span: Span, bcb: BasicCoverageBlock, is_hole: bool) -> Self { - Self { span, bcb, is_hole } + fn new(span: Span, bcb: BasicCoverageBlock) -> Self { + Self { span, bcb } } fn into_prev(self) -> PrevCovspan { - let Self { span, bcb, is_hole } = self; - PrevCovspan { span, bcb, merged_spans: vec![span], is_hole } - } - - fn into_refined(self) -> RefinedCovspan { - // This is only called in cases where `curr` is a hole span that has - // been carved out of `prev`. - debug_assert!(self.is_hole); - self.into_prev().into_refined() + let Self { span, bcb } = self; + PrevCovspan { span, bcb, merged_spans: vec![span] } } } @@ -64,12 +55,11 @@ struct PrevCovspan { /// List of all the original spans from MIR that have been merged into this /// span. Mainly used to precisely skip over gaps when truncating a span. merged_spans: Vec, - is_hole: bool, } impl PrevCovspan { fn is_mergeable(&self, other: &CurrCovspan) -> bool { - self.bcb == other.bcb && !self.is_hole && !other.is_hole + self.bcb == other.bcb } fn merge_from(&mut self, other: &CurrCovspan) { @@ -88,8 +78,8 @@ impl PrevCovspan { } fn refined_copy(&self) -> RefinedCovspan { - let &Self { span, bcb, merged_spans: _, is_hole } = self; - RefinedCovspan { span, bcb, is_hole } + let &Self { span, bcb, merged_spans: _ } = self; + RefinedCovspan { span, bcb } } fn into_refined(self) -> RefinedCovspan { @@ -102,12 +92,11 @@ impl PrevCovspan { struct RefinedCovspan { span: Span, bcb: BasicCoverageBlock, - is_hole: bool, } impl RefinedCovspan { fn is_mergeable(&self, other: &Self) -> bool { - self.bcb == other.bcb && !self.is_hole && !other.is_hole + self.bcb == other.bcb } fn merge_from(&mut self, other: &Self) { @@ -122,8 +111,6 @@ impl RefinedCovspan { /// * Remove duplicate source code coverage regions /// * Merge spans that represent continuous (both in source code and control flow), non-branching /// execution -/// * Carve out (leave uncovered) any "hole" spans that need to be left blank -/// (e.g. closures that will be counted by their own MIR body) struct SpansRefiner { /// The initial set of coverage spans, sorted by `Span` (`lo` and `hi`) and by relative /// dominance between the `BasicCoverageBlock`s of equal `Span`s. @@ -184,13 +171,6 @@ impl SpansRefiner { ); let prev = self.take_prev().into_refined(); self.refined_spans.push(prev); - } else if prev.is_hole { - // drop any equal or overlapping span (`curr`) and keep `prev` to test again in the - // next iter - debug!(?prev, "prev (a hole) overlaps curr, so discarding curr"); - self.take_curr(); // Discards curr. - } else if curr.is_hole { - self.carve_out_span_for_hole(); } else { self.cutoff_prev_at_overlapping_curr(); } @@ -214,9 +194,6 @@ impl SpansRefiner { } }); - // Discard hole spans, since their purpose was to carve out chunks from - // other spans, but we don't want the holes themselves in the final mappings. - self.refined_spans.retain(|covspan| !covspan.is_hole); self.refined_spans } @@ -252,50 +229,17 @@ impl SpansRefiner { if let Some(curr) = self.some_curr.take() { self.some_prev = Some(curr.into_prev()); } - while let Some(curr) = self.sorted_spans_iter.next() { - debug!("FOR curr={:?}", curr); - if let Some(prev) = &self.some_prev - && prev.span.lo() > curr.span.lo() - { - // Skip curr because prev has already advanced beyond the end of curr. - // This can only happen if a prior iteration updated `prev` to skip past - // a region of code, such as skipping past a hole. - debug!(?prev, "prev.span starts after curr.span, so curr will be dropped"); - } else { - self.some_curr = Some(CurrCovspan::new(curr.span, curr.bcb, false)); - return true; + if let Some(SpanFromMir { span, bcb, .. }) = self.sorted_spans_iter.next() { + // This code only sees sorted spans after hole-carving, so there should + // be no way for `curr` to start before `prev`. + if let Some(prev) = &self.some_prev { + debug_assert!(prev.span.lo() <= span.lo()); } - } - false - } - - /// If `prev`s span extends left of the hole (`curr`), carve out the hole's span from - /// `prev`'s span. Add the portion of the span to the left of the hole; and if the span - /// extends to the right of the hole, update `prev` to that portion of the span. - fn carve_out_span_for_hole(&mut self) { - let prev = self.prev(); - let curr = self.curr(); - - let left_cutoff = curr.span.lo(); - let right_cutoff = curr.span.hi(); - let has_pre_hole_span = prev.span.lo() < right_cutoff; - let has_post_hole_span = prev.span.hi() > right_cutoff; - - if has_pre_hole_span { - let mut pre_hole = prev.refined_copy(); - pre_hole.span = pre_hole.span.with_hi(left_cutoff); - debug!(?pre_hole, "prev overlaps a hole; adding pre-hole span"); - self.refined_spans.push(pre_hole); - } - - if has_post_hole_span { - // Mutate `prev.span` to start after the hole (and discard curr). - self.prev_mut().span = self.prev().span.with_lo(right_cutoff); - debug!(prev=?self.prev(), "mutated prev to start after the hole"); - - // Prevent this curr from becoming prev. - let hole_covspan = self.take_curr().into_refined(); - self.refined_spans.push(hole_covspan); // since self.prev() was already updated + self.some_curr = Some(CurrCovspan::new(span, bcb)); + debug!(?self.some_prev, ?self.some_curr, "next_coverage_span"); + true + } else { + false } }