coverage. Generate Mappings of decisions and conditions for MC/DC

1 files changed, 59 insertions, 10 deletions

diff --git a/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs b/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs
index adb0c9f1929..b9919a2ae88 100644
--- a/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs
+++ b/compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs
@@ -1,7 +1,9 @@
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_index::IndexVec;
-use rustc_middle::mir::coverage::{BlockMarkerId, BranchSpan, CoverageKind};
+use rustc_middle::mir::coverage::{
+    BlockMarkerId, BranchSpan, CoverageKind, MCDCBranchSpan, MCDCDecisionSpan,
+};
 use rustc_middle::mir::{
     self, AggregateKind, BasicBlock, FakeReadCause, Rvalue, Statement, StatementKind, Terminator,
     TerminatorKind,
@@ -227,7 +229,10 @@ fn filtered_statement_span(statement: &Statement<'_>) -> Option<Span> {
 
         // These coverage statements should not exist prior to coverage instrumentation.
         StatementKind::Coverage(
-            CoverageKind::CounterIncrement { .. } | CoverageKind::ExpressionUsed { .. },
+            CoverageKind::CounterIncrement { .. }
+            | CoverageKind::ExpressionUsed { .. }
+            | CoverageKind::CondBitmapUpdate { .. }
+            | CoverageKind::TestVectorBitmapUpdate { .. },
         ) => bug!(
             "Unexpected coverage statement found during coverage instrumentation: {statement:?}"
         ),
@@ -384,10 +389,11 @@ pub(super) fn extract_branch_mappings(
         }
     }
 
-    branch_info
-        .branch_spans
-        .iter()
-        .filter_map(|&BranchSpan { span: raw_span, true_marker, false_marker }| {
+    let bcb_from_marker =
+        |marker: BlockMarkerId| basic_coverage_blocks.bcb_from_bb(block_markers[marker]?);
+
+    let check_branch_bcb =
+        |raw_span: Span, true_marker: BlockMarkerId, false_marker: BlockMarkerId| {
             // For now, ignore any branch span that was introduced by
             // expansion. This makes things like assert macros less noisy.
             if !raw_span.ctxt().outer_expn_data().is_root() {
@@ -395,13 +401,56 @@ pub(super) fn extract_branch_mappings(
             }
             let (span, _) = unexpand_into_body_span_with_visible_macro(raw_span, body_span)?;
 
-            let bcb_from_marker =
-                |marker: BlockMarkerId| basic_coverage_blocks.bcb_from_bb(block_markers[marker]?);
-
             let true_bcb = bcb_from_marker(true_marker)?;
             let false_bcb = bcb_from_marker(false_marker)?;
+            Some((span, true_bcb, false_bcb))
+        };
 
-            Some(BcbMapping { kind: BcbMappingKind::Branch { true_bcb, false_bcb }, span })
+    let branch_filter_map = |&BranchSpan { span: raw_span, true_marker, false_marker }| {
+        check_branch_bcb(raw_span, true_marker, false_marker).map(|(span, true_bcb, false_bcb)| {
+            BcbMapping { kind: BcbMappingKind::Branch { true_bcb, false_bcb }, span }
         })
+    };
+
+    let mcdc_branch_filter_map =
+        |&MCDCBranchSpan { span: raw_span, true_marker, false_marker, condition_info }| {
+            check_branch_bcb(raw_span, true_marker, false_marker).map(
+                |(span, true_bcb, false_bcb)| BcbMapping {
+                    kind: BcbMappingKind::MCDCBranch { true_bcb, false_bcb, condition_info },
+                    span,
+                },
+            )
+        };
+
+    let mut next_bitmap_idx = 0;
+
+    let decision_filter_map = |decision: &MCDCDecisionSpan| {
+        let (span, _) = unexpand_into_body_span_with_visible_macro(decision.span, body_span)?;
+
+        let end_bcbs = decision
+            .end_markers
+            .iter()
+            .map(|&marker| bcb_from_marker(marker))
+            .collect::<Option<_>>()?;
+
+        let bitmap_idx = next_bitmap_idx;
+        next_bitmap_idx += (1_u32 << decision.conditions_num).div_ceil(8);
+
+        Some(BcbMapping {
+            kind: BcbMappingKind::MCDCDecision {
+                end_bcbs,
+                bitmap_idx,
+                conditions_num: decision.conditions_num as u16,
+            },
+            span,
+        })
+    };
+
+    branch_info
+        .branch_spans
+        .iter()
+        .filter_map(branch_filter_map)
+        .chain(branch_info.mcdc_branch_spans.iter().filter_map(mcdc_branch_filter_map))
+        .chain(branch_info.mcdc_decision_spans.iter().filter_map(decision_filter_map))
         .collect::<Vec<_>>()
 }