Rollup merge of #139966 - Zalathar:span-merge, r=oli-obk

coverage: Only merge adjacent coverage spans

For a long time, coverage instrumentation has automatically “merged” spans with the same control-flow into a smaller number of larger spans, even when the spans being merged are not overlapping or adjacent. This causes any source text between the original spans to be included in the merged span, which is then associated with an execution count when shown in coverage reports.

That approach causes a number of problems:
- The intervening source text can contain all sorts of things that shouldn't really be marked as executable code (e.g. nested items, parts of macro invocations, long comments). In some cases we have complicated workarounds (e.g. bucketing to avoid merging spans across nested items), but in other cases there isn't much we can do.
- Merging can have aesthetically weird effects, such as including unbalanced parentheses, because the merging process doesn't really understand what it's doing at a source code level.
- It generally leads to an accumulation of piled-on heuristics and special cases that give decent-looking results, but are fiendishly difficult to modify or replace.

Therefore, this PR aims to abolish the merging of non-adjacent coverage spans.

The big tradeoff here is that the resulting coverage metadata (embedded in the instrumented binary) tends to become larger, because the overall number of distinct spans has increased. That's unfortunate, but I see it as the inevitable cost of cleaning up the messes and inaccuracies that were caused by the old approach. And the resulting spans do tend to be more accurate to the program's actual control-flow.

---

The `.coverage` snapshot changes give an indication of how this PR will affect user-visible coverage reports. In many cases the changes to reporting are minor or even nonexistent, despite substantial changes to the metadata (as indicated by `.cov-map` snapshots).

---

try-job: aarch64-gnu

Author: GuillaumeGomez

compiler/rustc_mir_transform/src/coverage/mappings.rs

@@ -91,7 +91,7 @@ pub(super) fn extract_all_mapping_info_from_mir<'tcx>(
         // When debugging flag `-Zcoverage-options=no-mir-spans` is set, we need
         // to give the same treatment to _all_ functions, because `llvm-cov`
         // seems to ignore functions that don't have any ordinary code spans.
-        if let Some(span) = hir_info.fn_sig_span_extended {
+        if let Some(span) = hir_info.fn_sig_span {
             code_mappings.push(CodeMapping { span, bcb: START_BCB });
         }
     } else {

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -268,9 +268,9 @@ fn inject_statement(mir_body: &mut mir::Body<'_>, counter_kind: CoverageKind, bb
 struct ExtractedHirInfo {
     function_source_hash: u64,
     is_async_fn: bool,
-    /// The span of the function's signature, extended to the start of `body_span`.
+    /// The span of the function's signature, if available.
     /// Must have the same context and filename as the body span.
-    fn_sig_span_extended: Option<Span>,
+    fn_sig_span: Option<Span>,
     body_span: Span,
     /// "Holes" are regions within the function body (or its expansions) that
     /// should not be included in coverage spans for this function
@@ -308,30 +308,20 @@ fn extract_hir_info<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> ExtractedHir
 
     // The actual signature span is only used if it has the same context and
     // filename as the body, and precedes the body.
-    let fn_sig_span_extended = maybe_fn_sig
-        .map(|fn_sig| fn_sig.span)
-        .filter(|&fn_sig_span| {
-            let source_map = tcx.sess.source_map();
-            let file_idx = |span: Span| source_map.lookup_source_file_idx(span.lo());
-
-            fn_sig_span.eq_ctxt(body_span)
-                && fn_sig_span.hi() <= body_span.lo()
-                && file_idx(fn_sig_span) == file_idx(body_span)
-        })
-        // If so, extend it to the start of the body span.
-        .map(|fn_sig_span| fn_sig_span.with_hi(body_span.lo()));
+    let fn_sig_span = maybe_fn_sig.map(|fn_sig| fn_sig.span).filter(|&fn_sig_span| {
+        let source_map = tcx.sess.source_map();
+        let file_idx = |span: Span| source_map.lookup_source_file_idx(span.lo());
+
+        fn_sig_span.eq_ctxt(body_span)
+            && fn_sig_span.hi() <= body_span.lo()
+            && file_idx(fn_sig_span) == file_idx(body_span)
+    });
 
     let function_source_hash = hash_mir_source(tcx, hir_body);
 
     let hole_spans = extract_hole_spans_from_hir(tcx, hir_body);
 
-    ExtractedHirInfo {
-        function_source_hash,
-        is_async_fn,
-        fn_sig_span_extended,
-        body_span,
-        hole_spans,
-    }
+    ExtractedHirInfo { function_source_hash, is_async_fn, fn_sig_span, body_span, hole_spans }
 }
 
 fn hash_mir_source<'tcx>(tcx: TyCtxt<'tcx>, hir_body: &'tcx hir::Body<'tcx>) -> u64 {

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -1,11 +1,8 @@
-use std::collections::VecDeque;
-use std::iter;
-
 use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::mir;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::{DesugaringKind, ExpnKind, MacroKind, Span};
-use tracing::{debug, debug_span, instrument};
+use tracing::instrument;
 
 use crate::coverage::graph::{BasicCoverageBlock, CoverageGraph};
 use crate::coverage::spans::from_mir::{Hole, RawSpanFromMir, SpanFromMir};
@@ -42,12 +39,12 @@ pub(super) fn extract_refined_covspans<'tcx>(
         return;
     }
 
-    // Also add the adjusted function signature span, if available.
+    // Also add the function signature span, if available.
     // Otherwise, add a fake span at the start of the body, to avoid an ugly
     // gap between the start of the body and the first real span.
     // FIXME: Find a more principled way to solve this problem.
     covspans.push(SpanFromMir::for_fn_sig(
-        hir_info.fn_sig_span_extended.unwrap_or_else(|| body_span.shrink_to_lo()),
+        hir_info.fn_sig_span.unwrap_or_else(|| body_span.shrink_to_lo()),
     ));
 
     // First, perform the passes that need macro information.
@@ -83,24 +80,17 @@ pub(super) fn extract_refined_covspans<'tcx>(
     holes.sort_by(|a, b| compare_spans(a.span, b.span));
     holes.dedup_by(|b, a| a.merge_if_overlapping_or_adjacent(b));
 
-    // Split the covspans into separate buckets that don't overlap any holes.
-    let buckets = divide_spans_into_buckets(covspans, &holes);
-
-    for covspans in buckets {
-        let _span = debug_span!("processing bucket", ?covspans).entered();
+    // Discard any span that overlaps with a hole.
+    discard_spans_overlapping_holes(&mut covspans, &holes);
 
-        let mut covspans = remove_unwanted_overlapping_spans(covspans);
-        debug!(?covspans, "after removing overlaps");
+    // Perform more refinement steps after holes have been dealt with.
+    let mut covspans = remove_unwanted_overlapping_spans(covspans);
+    covspans.dedup_by(|b, a| a.merge_if_eligible(b));
 
-        // Do one last merge pass, to simplify the output.
-        covspans.dedup_by(|b, a| a.merge_if_eligible(b));
-        debug!(?covspans, "after merge");
-
-        code_mappings.extend(covspans.into_iter().map(|Covspan { span, bcb }| {
-            // Each span produced by the refiner represents an ordinary code region.
-            mappings::CodeMapping { span, bcb }
-        }));
-    }
+    code_mappings.extend(covspans.into_iter().map(|Covspan { span, bcb }| {
+        // Each span produced by the refiner represents an ordinary code region.
+        mappings::CodeMapping { span, bcb }
+    }));
 }
 
 /// Macros that expand into branches (e.g. `assert!`, `trace!`) tend to generate
@@ -142,52 +132,36 @@ fn shrink_visible_macro_spans(tcx: TyCtxt<'_>, covspans: &mut Vec<SpanFromMir>)
     }
 }
 
-/// Uses the holes to divide the given covspans into buckets, such that:
-/// - No span in any hole overlaps a bucket (discarding spans if necessary).
-/// - The spans in each bucket are strictly after all spans in previous buckets,
-///   and strictly before all spans in subsequent buckets.
+/// Discard all covspans that overlap a hole.
 ///
-/// The lists of covspans and holes must be sorted.
-/// The resulting buckets are sorted relative to each other, and each bucket's
-/// contents are sorted.
-#[instrument(level = "debug")]
-fn divide_spans_into_buckets(input_covspans: Vec<Covspan>, holes: &[Hole]) -> Vec<Vec<Covspan>> {
-    debug_assert!(input_covspans.is_sorted_by(|a, b| compare_spans(a.span, b.span).is_le()));
+/// The lists of covspans and holes must be sorted, and any holes that overlap
+/// with each other must have already been merged.
+fn discard_spans_overlapping_holes(covspans: &mut Vec<Covspan>, holes: &[Hole]) {
+    debug_assert!(covspans.is_sorted_by(|a, b| compare_spans(a.span, b.span).is_le()));
     debug_assert!(holes.is_sorted_by(|a, b| compare_spans(a.span, b.span).is_le()));
+    debug_assert!(holes.array_windows().all(|[a, b]| !a.span.overlaps_or_adjacent(b.span)));
+
+    let mut curr_hole = 0usize;
+    let mut overlaps_hole = |covspan: &Covspan| -> bool {
+        while let Some(hole) = holes.get(curr_hole) {
+            // Both lists are sorted, so we can permanently skip any holes that
+            // end before the start of the current span.
+            if hole.span.hi() <= covspan.span.lo() {
+                curr_hole += 1;
+                continue;
+            }
 
-    // Now we're ready to start grouping spans into buckets separated by holes.
-
-    let mut input_covspans = VecDeque::from(input_covspans);
-
-    // For each hole:
-    // - Identify the spans that are entirely or partly before the hole.
-    // - Discard any that overlap with the hole.
-    // - Add the remaining identified spans to the corresponding bucket.
-    let mut buckets = (0..holes.len()).map(|_| vec![]).collect::<Vec<_>>();
-    for (hole, bucket) in holes.iter().zip(&mut buckets) {
-        bucket.extend(
-            drain_front_while(&mut input_covspans, |c| c.span.lo() < hole.span.hi())
-                .filter(|c| !c.span.overlaps(hole.span)),
-        );
-    }
-
-    // Any remaining spans form their own final bucket, after the final hole.
-    // (If there were no holes, this will just be all of the initial spans.)
-    buckets.push(Vec::from(input_covspans));
+            return hole.span.overlaps(covspan.span);
+        }
 
-    buckets
-}
+        // No holes left, so this covspan doesn't overlap with any holes.
+        false
+    };
 
-/// Similar to `.drain(..)`, but stops just before it would remove an item not
-/// satisfying the predicate.
-fn drain_front_while<'a, T>(
-    queue: &'a mut VecDeque<T>,
-    mut pred_fn: impl FnMut(&T) -> bool,
-) -> impl Iterator<Item = T> {
-    iter::from_fn(move || queue.pop_front_if(|x| pred_fn(x)))
+    covspans.retain(|covspan| !overlaps_hole(covspan));
 }
 
-/// Takes one of the buckets of (sorted) spans extracted from MIR, and "refines"
+/// Takes a list of sorted spans extracted from MIR, and "refines"
 /// those spans by removing spans that overlap in unwanted ways.
 #[instrument(level = "debug")]
 fn remove_unwanted_overlapping_spans(sorted_spans: Vec<Covspan>) -> Vec<Covspan> {
@@ -227,19 +201,21 @@ struct Covspan {
 }
 
 impl Covspan {
-    /// If `self` and `other` can be merged (i.e. they have the same BCB),
-    /// mutates `self.span` to also include `other.span` and returns true.
+    /// If `self` and `other` can be merged, mutates `self.span` to also
+    /// include `other.span` and returns true.
     ///
-    /// Note that compatible covspans can be merged even if their underlying
-    /// spans are not overlapping/adjacent; any space between them will also be
-    /// part of the merged covspan.
+    /// Two covspans can be merged if they have the same BCB, and they are
+    /// overlapping or adjacent.
     fn merge_if_eligible(&mut self, other: &Self) -> bool {
-        if self.bcb != other.bcb {
-            return false;
+        let eligible_for_merge =
+            |a: &Self, b: &Self| (a.bcb == b.bcb) && a.span.overlaps_or_adjacent(b.span);
+
+        if eligible_for_merge(self, other) {
+            self.span = self.span.to(other.span);
+            true
+        } else {
+            false
         }
-
-        self.span = self.span.to(other.span);
-        true
     }
 }
 

tests/coverage/abort.cov-map

@@ -1,5 +1,5 @@
 Function name: abort::main
-Raw bytes (83): 0x[01, 01, 07, 05, 01, 05, 0b, 01, 09, 05, 13, 01, 0d, 05, 1b, 01, 11, 0d, 01, 0d, 01, 01, 1b, 05, 02, 0b, 00, 18, 02, 01, 0c, 00, 19, 09, 00, 1a, 02, 0a, 06, 02, 09, 00, 0a, 02, 02, 0c, 00, 19, 0d, 00, 1a, 00, 31, 0e, 00, 30, 00, 31, 02, 04, 0c, 00, 19, 11, 00, 1a, 00, 31, 16, 00, 30, 00, 31, 02, 01, 09, 00, 17, 01, 02, 05, 01, 02]
+Raw bytes (98): 0x[01, 01, 07, 05, 01, 05, 0b, 01, 09, 05, 13, 01, 0d, 05, 1b, 01, 11, 10, 01, 0d, 01, 00, 1c, 01, 01, 09, 00, 16, 01, 00, 19, 00, 1b, 05, 01, 0b, 00, 18, 02, 01, 0c, 00, 19, 09, 00, 1a, 02, 0a, 06, 02, 09, 00, 0a, 02, 02, 0c, 00, 19, 0d, 00, 1a, 00, 31, 0e, 00, 30, 00, 31, 02, 04, 0c, 00, 19, 11, 00, 1a, 00, 31, 16, 00, 30, 00, 31, 02, 01, 09, 00, 17, 01, 02, 05, 00, 0b, 01, 01, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/abort.rs
 Number of expressions: 7
@@ -10,9 +10,11 @@ Number of expressions: 7
 - expression 4 operands: lhs = Counter(0), rhs = Counter(3)
 - expression 5 operands: lhs = Counter(1), rhs = Expression(6, Add)
 - expression 6 operands: lhs = Counter(0), rhs = Counter(4)
-Number of file 0 mappings: 13
-- Code(Counter(0)) at (prev + 13, 1) to (start + 1, 27)
-- Code(Counter(1)) at (prev + 2, 11) to (start + 0, 24)
+Number of file 0 mappings: 16
+- Code(Counter(0)) at (prev + 13, 1) to (start + 0, 28)
+- Code(Counter(0)) at (prev + 1, 9) to (start + 0, 22)
+- Code(Counter(0)) at (prev + 0, 25) to (start + 0, 27)
+- Code(Counter(1)) at (prev + 1, 11) to (start + 0, 24)
 - Code(Expression(0, Sub)) at (prev + 1, 12) to (start + 0, 25)
     = (c1 - c0)
 - Code(Counter(2)) at (prev + 0, 26) to (start + 2, 10)
@@ -30,19 +32,25 @@ Number of file 0 mappings: 13
     = (c1 - (c0 + c4))
 - Code(Expression(0, Sub)) at (prev + 1, 9) to (start + 0, 23)
     = (c1 - c0)
-- Code(Counter(0)) at (prev + 2, 5) to (start + 1, 2)
+- Code(Counter(0)) at (prev + 2, 5) to (start + 0, 11)
+- Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
 Highest counter ID seen: c4
 
 Function name: abort::might_abort
-Raw bytes (21): 0x[01, 01, 01, 01, 05, 03, 01, 03, 01, 01, 14, 05, 02, 09, 01, 0f, 02, 02, 0c, 03, 02]
+Raw bytes (41): 0x[01, 01, 01, 01, 05, 07, 01, 03, 01, 00, 2e, 01, 01, 08, 00, 14, 05, 01, 09, 00, 11, 05, 00, 12, 00, 1f, 05, 01, 09, 00, 0f, 02, 01, 0c, 02, 06, 02, 03, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/abort.rs
 Number of expressions: 1
 - expression 0 operands: lhs = Counter(0), rhs = Counter(1)
-Number of file 0 mappings: 3
-- Code(Counter(0)) at (prev + 3, 1) to (start + 1, 20)
-- Code(Counter(1)) at (prev + 2, 9) to (start + 1, 15)
-- Code(Expression(0, Sub)) at (prev + 2, 12) to (start + 3, 2)
+Number of file 0 mappings: 7
+- Code(Counter(0)) at (prev + 3, 1) to (start + 0, 46)
+- Code(Counter(0)) at (prev + 1, 8) to (start + 0, 20)
+- Code(Counter(1)) at (prev + 1, 9) to (start + 0, 17)
+- Code(Counter(1)) at (prev + 0, 18) to (start + 0, 31)
+- Code(Counter(1)) at (prev + 1, 9) to (start + 0, 15)
+- Code(Expression(0, Sub)) at (prev + 1, 12) to (start + 2, 6)
+    = (c0 - c1)
+- Code(Expression(0, Sub)) at (prev + 3, 1) to (start + 0, 2)
     = (c0 - c1)
 Highest counter ID seen: c1
 

tests/coverage/assert-ne.cov-map

@@ -1,16 +1,23 @@
 Function name: assert_ne::main
-Raw bytes (28): 0x[01, 01, 02, 01, 05, 01, 09, 04, 01, 08, 01, 03, 15, 05, 04, 0d, 00, 13, 02, 02, 0d, 00, 13, 06, 03, 05, 01, 02]
+Raw bytes (55): 0x[01, 01, 03, 01, 05, 01, 09, 01, 09, 09, 01, 08, 01, 00, 0a, 01, 01, 05, 00, 0f, 01, 01, 09, 00, 12, 01, 00, 13, 00, 19, 01, 01, 0c, 00, 15, 05, 01, 0d, 00, 13, 02, 02, 0d, 00, 13, 0a, 03, 05, 00, 07, 0a, 01, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/assert-ne.rs
-Number of expressions: 2
+Number of expressions: 3
 - expression 0 operands: lhs = Counter(0), rhs = Counter(1)
 - expression 1 operands: lhs = Counter(0), rhs = Counter(2)
-Number of file 0 mappings: 4
-- Code(Counter(0)) at (prev + 8, 1) to (start + 3, 21)
-- Code(Counter(1)) at (prev + 4, 13) to (start + 0, 19)
+- expression 2 operands: lhs = Counter(0), rhs = Counter(2)
+Number of file 0 mappings: 9
+- Code(Counter(0)) at (prev + 8, 1) to (start + 0, 10)
+- Code(Counter(0)) at (prev + 1, 5) to (start + 0, 15)
+- Code(Counter(0)) at (prev + 1, 9) to (start + 0, 18)
+- Code(Counter(0)) at (prev + 0, 19) to (start + 0, 25)
+- Code(Counter(0)) at (prev + 1, 12) to (start + 0, 21)
+- Code(Counter(1)) at (prev + 1, 13) to (start + 0, 19)
 - Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 19)
     = (c0 - c1)
-- Code(Expression(1, Sub)) at (prev + 3, 5) to (start + 1, 2)
+- Code(Expression(2, Sub)) at (prev + 3, 5) to (start + 0, 7)
+    = (c0 - c2)
+- Code(Expression(2, Sub)) at (prev + 1, 1) to (start + 0, 2)
     = (c0 - c2)
 Highest counter ID seen: c1
 

tests/coverage/assert.cov-map

@@ -1,5 +1,5 @@
 Function name: assert::main
-Raw bytes (61): 0x[01, 01, 06, 05, 01, 05, 17, 01, 09, 05, 13, 17, 0d, 01, 09, 09, 01, 09, 01, 01, 1b, 05, 02, 0b, 00, 18, 02, 01, 0c, 00, 1a, 09, 00, 1b, 02, 0a, 06, 02, 13, 00, 20, 0d, 00, 21, 02, 0a, 0e, 02, 09, 00, 0a, 02, 01, 09, 00, 17, 01, 02, 05, 01, 02]
+Raw bytes (76): 0x[01, 01, 06, 05, 01, 05, 17, 01, 09, 05, 13, 17, 0d, 01, 09, 0c, 01, 09, 01, 00, 1c, 01, 01, 09, 00, 16, 01, 00, 19, 00, 1b, 05, 01, 0b, 00, 18, 02, 01, 0c, 00, 1a, 09, 00, 1b, 02, 0a, 06, 02, 13, 00, 20, 0d, 00, 21, 02, 0a, 0e, 02, 09, 00, 0a, 02, 01, 09, 00, 17, 01, 02, 05, 00, 0b, 01, 01, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/assert.rs
 Number of expressions: 6
@@ -9,9 +9,11 @@ Number of expressions: 6
 - expression 3 operands: lhs = Counter(1), rhs = Expression(4, Add)
 - expression 4 operands: lhs = Expression(5, Add), rhs = Counter(3)
 - expression 5 operands: lhs = Counter(0), rhs = Counter(2)
-Number of file 0 mappings: 9
-- Code(Counter(0)) at (prev + 9, 1) to (start + 1, 27)
-- Code(Counter(1)) at (prev + 2, 11) to (start + 0, 24)
+Number of file 0 mappings: 12
+- Code(Counter(0)) at (prev + 9, 1) to (start + 0, 28)
+- Code(Counter(0)) at (prev + 1, 9) to (start + 0, 22)
+- Code(Counter(0)) at (prev + 0, 25) to (start + 0, 27)
+- Code(Counter(1)) at (prev + 1, 11) to (start + 0, 24)
 - Code(Expression(0, Sub)) at (prev + 1, 12) to (start + 0, 26)
     = (c1 - c0)
 - Code(Counter(2)) at (prev + 0, 27) to (start + 2, 10)
@@ -22,18 +24,22 @@ Number of file 0 mappings: 9
     = (c1 - ((c0 + c2) + c3))
 - Code(Expression(0, Sub)) at (prev + 1, 9) to (start + 0, 23)
     = (c1 - c0)
-- Code(Counter(0)) at (prev + 2, 5) to (start + 1, 2)
+- Code(Counter(0)) at (prev + 2, 5) to (start + 0, 11)
+- Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
 Highest counter ID seen: c3
 
 Function name: assert::might_fail_assert
-Raw bytes (21): 0x[01, 01, 01, 01, 05, 03, 01, 04, 01, 02, 0f, 02, 02, 25, 00, 3d, 05, 01, 01, 00, 02]
+Raw bytes (36): 0x[01, 01, 01, 01, 05, 06, 01, 04, 01, 00, 28, 01, 01, 05, 00, 0d, 01, 00, 0e, 00, 20, 01, 01, 05, 00, 0f, 02, 00, 25, 00, 3d, 05, 01, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/assert.rs
 Number of expressions: 1
 - expression 0 operands: lhs = Counter(0), rhs = Counter(1)
-Number of file 0 mappings: 3
-- Code(Counter(0)) at (prev + 4, 1) to (start + 2, 15)
-- Code(Expression(0, Sub)) at (prev + 2, 37) to (start + 0, 61)
+Number of file 0 mappings: 6
+- Code(Counter(0)) at (prev + 4, 1) to (start + 0, 40)
+- Code(Counter(0)) at (prev + 1, 5) to (start + 0, 13)
+- Code(Counter(0)) at (prev + 0, 14) to (start + 0, 32)
+- Code(Counter(0)) at (prev + 1, 5) to (start + 0, 15)
+- Code(Expression(0, Sub)) at (prev + 0, 37) to (start + 0, 61)
     = (c0 - c1)
 - Code(Counter(1)) at (prev + 1, 1) to (start + 0, 2)
 Highest counter ID seen: c1

tests/coverage/assert_not.cov-map

@@ -1,13 +1,18 @@
 Function name: assert_not::main
-Raw bytes (29): 0x[01, 01, 00, 05, 01, 06, 01, 01, 11, 01, 02, 05, 00, 13, 01, 01, 05, 00, 13, 01, 01, 05, 00, 15, 01, 01, 01, 00, 02]
+Raw bytes (54): 0x[01, 01, 00, 0a, 01, 06, 01, 00, 0a, 01, 01, 05, 00, 0c, 01, 00, 0d, 00, 11, 01, 01, 05, 00, 0c, 01, 00, 0d, 00, 13, 01, 01, 05, 00, 0c, 01, 00, 0d, 00, 13, 01, 01, 05, 00, 0c, 01, 00, 0d, 00, 15, 01, 01, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/assert_not.rs
 Number of expressions: 0
-Number of file 0 mappings: 5
-- Code(Counter(0)) at (prev + 6, 1) to (start + 1, 17)
-- Code(Counter(0)) at (prev + 2, 5) to (start + 0, 19)
-- Code(Counter(0)) at (prev + 1, 5) to (start + 0, 19)
-- Code(Counter(0)) at (prev + 1, 5) to (start + 0, 21)
+Number of file 0 mappings: 10
+- Code(Counter(0)) at (prev + 6, 1) to (start + 0, 10)
+- Code(Counter(0)) at (prev + 1, 5) to (start + 0, 12)
+- Code(Counter(0)) at (prev + 0, 13) to (start + 0, 17)
+- Code(Counter(0)) at (prev + 1, 5) to (start + 0, 12)
+- Code(Counter(0)) at (prev + 0, 13) to (start + 0, 19)
+- Code(Counter(0)) at (prev + 1, 5) to (start + 0, 12)
+- Code(Counter(0)) at (prev + 0, 13) to (start + 0, 19)
+- Code(Counter(0)) at (prev + 1, 5) to (start + 0, 12)
+- Code(Counter(0)) at (prev + 0, 13) to (start + 0, 21)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
 Highest counter ID seen: c0