mcdc-coverage: rename Decision marker to MCDCDecisionEntryMarker, add output marker

Author: RenjiSann

compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs

@@ -107,7 +107,8 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
             CoverageKind::SpanMarker
             | CoverageKind::BlockMarker { .. }
             | CoverageKind::MCDCBlockMarker { .. }
-            | CoverageKind::MCDCDecisionMarker { .. } => unreachable!(
+            | CoverageKind::MCDCDecisionEntryMarker { .. }
+            | CoverageKind::MCDCDecisionOutputMarker { .. } => unreachable!(
                 "marker statement {kind:?} should have been removed by CleanupPostBorrowck"
             ),
             CoverageKind::CounterIncrement { id } => {

compiler/rustc_middle/src/mir/coverage.rs

@@ -114,7 +114,14 @@ pub enum CoverageKind {
     /// conditions in the same decision will reference this id.
     ///
     /// Has no effect during codegen.
-    MCDCDecisionMarker { id: DecisionMarkerId },
+    MCDCDecisionEntryMarker { id: DecisionMarkerId },
+
+    /// Marks one of the basic blocks following the decision referenced with `id`.
+    /// the outcome bool designates which branch of the decision it is:
+    /// `true` for the then block, `false` for the else block.
+    ///
+    /// Has no effect during codegen.
+    MCDCDecisionOutputMarker { id: DecisionMarkerId, outcome: bool },
 
     /// Declares the number of bytes needed to store the test-vector bitmaps of
     /// all the decisions in the function body.
@@ -151,8 +158,15 @@ impl Debug for CoverageKind {
             MCDCBlockMarker { id, decision_id } => {
                 write!(fmt, "MCDCBlockMarker({:?}, {:?})", id.index(), decision_id.index())
             }
-            MCDCDecisionMarker { id } => write!(fmt, "MCDCDecisionMarker({:?})", id.index()),
-            MCDCBitmapRequire { needed_bytes } => write!(fmt, "MCDCBitmapRequire({needed_bytes} bytes)"),
+            MCDCDecisionEntryMarker { id } => {
+                write!(fmt, "MCDCDecisionEntryMarker({:?})", id.index())
+            }
+            &MCDCDecisionOutputMarker { id, outcome } => {
+                write!(fmt, "MCDCDecisionOutputMarker({:?}, {})", id.index(), outcome)
+            }
+            MCDCBitmapRequire { needed_bytes } => {
+                write!(fmt, "MCDCBitmapRequire({needed_bytes} bytes)")
+            }
             CounterIncrement { id } => write!(fmt, "CounterIncrement({:?})", id.index()),
             ExpressionUsed { id } => write!(fmt, "ExpressionUsed({:?})", id.index()),
         }

compiler/rustc_mir_build/src/build/coverageinfo.rs

@@ -106,9 +106,7 @@ impl BranchInfoBuilder {
         }
 
         let mut decision_spans = IndexVec::from_iter(
-            decisions
-                .into_iter()
-                .map(|span| DecisionSpan { span, num_conditions: 0 }),
+            decisions.into_iter().map(|span| DecisionSpan { span, num_conditions: 0 }),
         );
 
         // Count the number of conditions linked to each decision.
@@ -161,10 +159,8 @@ impl Builder<'_, '_> {
                 CoverageKind::BlockMarker { id }
             };
 
-            let marker_statement = mir::Statement {
-                source_info,
-                kind: mir::StatementKind::Coverage(cov_kind),
-            };
+            let marker_statement =
+                mir::Statement { source_info, kind: mir::StatementKind::Coverage(cov_kind) };
             self.cfg.push(block, marker_statement);
 
             id
@@ -204,9 +200,9 @@ impl Builder<'_, '_> {
         let source_info = self.source_info(span);
         let marker_statement = mir::Statement {
             source_info,
-            kind: mir::StatementKind::Coverage(
-                CoverageKind::MCDCDecisionMarker { id: decision_id },
-            ),
+            kind: mir::StatementKind::Coverage(CoverageKind::MCDCDecisionEntryMarker {
+                id: decision_id,
+            }),
         };
         self.cfg.push(block, marker_statement);
 

compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs

@@ -38,7 +38,8 @@ impl<'tcx> MirPass<'tcx> for CleanupPostBorrowck {
                         CoverageKind::BlockMarker { .. }
                         | CoverageKind::SpanMarker { .. }
                         | CoverageKind::MCDCBlockMarker { .. }
-                        | CoverageKind::MCDCDecisionMarker { .. },
+                        | CoverageKind::MCDCDecisionEntryMarker { .. }
+                        | CoverageKind::MCDCDecisionOutputMarker { .. },
                     )
                     | StatementKind::FakeRead(..) => statement.make_nop(),
                     _ => (),

compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs

@@ -227,7 +227,8 @@ fn filtered_statement_span(statement: &Statement<'_>) -> Option<Span> {
             CoverageKind::BlockMarker {..}
             // Ignore MCDC markers as well
             | CoverageKind::MCDCBlockMarker{ .. }
-            | CoverageKind::MCDCDecisionMarker{ .. }
+            | CoverageKind::MCDCDecisionEntryMarker{ .. }
+            | CoverageKind::MCDCDecisionOutputMarker { .. }
         ) => None,
 
         // These coverage statements should not exist prior to coverage instrumentation.