CoverageMappingReader/Writer: MCDCConditionID shouldn't be zero

Author: chapuni

llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp

@@ -308,6 +308,10 @@ Error RawCoverageMappingReader::readMappingRegionsSubArray(
             return Err;
           if (auto Err = readIntMax(FID, std::numeric_limits<unsigned>::max()))
             return Err;
+          if (ID == 0)
+            return make_error<CoverageMapError>(
+                coveragemap_error::malformed,
+                "MCDCConditionID shouldn't be zero");
           break;
         case CounterMappingRegion::MCDCDecisionRegion:
           Kind = CounterMappingRegion::MCDCDecisionRegion;

llvm/lib/ProfileData/Coverage/CoverageMappingWriter.cpp

@@ -251,6 +251,7 @@ void CoverageMappingWriter::write(raw_ostream &OS) {
                     OS);
       writeCounter(MinExpressions, Count, OS);
       writeCounter(MinExpressions, FalseCount, OS);
+      assert(I->MCDCParams.ID > 0);
       encodeULEB128(unsigned(I->MCDCParams.ID), OS);
       encodeULEB128(unsigned(I->MCDCParams.TrueID), OS);
       encodeULEB128(unsigned(I->MCDCParams.FalseID), OS);