Add MC/DC support to coverage test tools

2 files changed, 57 insertions, 2 deletions

diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index bb8509fe413..03580c0f14c 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -752,6 +752,19 @@ impl<'test> TestCx<'test> {
             Lazy::new(|| Regex::new(r"(?m:^)(?<prefix>(?:  \|)+  Branch \()[0-9]+:").unwrap());
         let coverage = BRANCH_LINE_NUMBER_RE.replace_all(&coverage, "${prefix}LL:");
 
+        // `  |---> MC/DC Decision Region (1:30) to (2:`     => `  |---> MC/DC Decision Region (LL:30) to (LL:`
+        static MCDC_DECISION_LINE_NUMBER_RE: Lazy<Regex> = Lazy::new(|| {
+            Regex::new(r"(?m:^)(?<prefix>(?:  \|)+---> MC/DC Decision Region \()[0-9]+:(?<middle>[0-9]+\) to \()[0-9]+:").unwrap()
+        });
+        let coverage =
+            MCDC_DECISION_LINE_NUMBER_RE.replace_all(&coverage, "${prefix}LL:${middle}LL:");
+
+        // `  |     Condition C1 --> (1:`     => `  |     Condition C1 --> (LL:`
+        static MCDC_CONDITION_LINE_NUMBER_RE: Lazy<Regex> = Lazy::new(|| {
+            Regex::new(r"(?m:^)(?<prefix>(?:  \|)+     Condition C[0-9]+ --> \()[0-9]+:").unwrap()
+        });
+        let coverage = MCDC_CONDITION_LINE_NUMBER_RE.replace_all(&coverage, "${prefix}LL:");
+
         coverage.into_owned()
     }
 
diff --git a/src/tools/coverage-dump/src/covfun.rs b/src/tools/coverage-dump/src/covfun.rs
index 49e3a6ed583..b308c8de14f 100644
--- a/src/tools/coverage-dump/src/covfun.rs
+++ b/src/tools/coverage-dump/src/covfun.rs
@@ -70,7 +70,8 @@ pub(crate) fn dump_covfun_mappings(
                     }
                     // If the mapping is a branch region, print both of its arms
                     // in resolved form (even if they aren't expressions).
-                    MappingKind::Branch { r#true, r#false } => {
+                    MappingKind::Branch { r#true, r#false }
+                    | MappingKind::MCDCBranch { r#true, r#false, .. } => {
                         println!("    true  = {}", expression_resolver.format_term(r#true));
                         println!("    false = {}", expression_resolver.format_term(r#false));
                     }
@@ -164,6 +165,26 @@ impl<'a> Parser<'a> {
                     let r#false = self.read_simple_term()?;
                     Ok(MappingKind::Branch { r#true, r#false })
                 }
+                5 => {
+                    let bitmap_idx = self.read_uleb128_u32()?;
+                    let conditions_num = self.read_uleb128_u32()?;
+                    Ok(MappingKind::MCDCDecision { bitmap_idx, conditions_num })
+                }
+                6 => {
+                    let r#true = self.read_simple_term()?;
+                    let r#false = self.read_simple_term()?;
+                    let condition_id = self.read_uleb128_u32()?;
+                    let true_next_id = self.read_uleb128_u32()?;
+                    let false_next_id = self.read_uleb128_u32()?;
+                    Ok(MappingKind::MCDCBranch {
+                        r#true,
+                        r#false,
+                        condition_id,
+                        true_next_id,
+                        false_next_id,
+                    })
+                }
+
                 _ => Err(anyhow!("unknown mapping kind: {raw_mapping_kind:#x}")),
             }
         }
@@ -224,7 +245,28 @@ enum MappingKind {
     // Using raw identifiers here makes the dump output a little bit nicer
     // (via the derived Debug), at the expense of making this tool's source
     // code a little bit uglier.
-    Branch { r#true: CovTerm, r#false: CovTerm },
+    Branch {
+        r#true: CovTerm,
+        r#false: CovTerm,
+    },
+    MCDCBranch {
+        r#true: CovTerm,
+        r#false: CovTerm,
+        // These attributes are printed in Debug but not used directly.
+        #[allow(dead_code)]
+        condition_id: u32,
+        #[allow(dead_code)]
+        true_next_id: u32,
+        #[allow(dead_code)]
+        false_next_id: u32,
+    },
+    MCDCDecision {
+        // These attributes are printed in Debug but not used directly.
+        #[allow(dead_code)]
+        bitmap_idx: u32,
+        #[allow(dead_code)]
+        conditions_num: u32,
+    },
 }
 
 struct MappingRegion {