fix use-of-uninitialized-memory error

Author: mingmingl-llvm

llvm/include/llvm/ProfileData/DataAccessProf.h

@@ -115,7 +115,7 @@ struct DataAccessProfRecord {
       Locations.emplace_back(Loc.FileName, Loc.Line);
   }
   // Empty constructor is used in yaml conversion.
-  DataAccessProfRecord() {}
+  DataAccessProfRecord() : AccessCount(0) {}
   SymbolHandle SymHandle;
   uint64_t AccessCount;
   // The locations of data in the source code. Optional.

llvm/include/llvm/ProfileData/MemProfYAML.h

@@ -248,7 +248,7 @@ template <> struct MappingTraits<memprof::DataAccessProfRecord> {
         Rec.SymHandle = Hash;
       }
     }
-
+    Io.mapRequired("AccessCount", Rec.AccessCount);
     Io.mapOptional("Locations", Rec.Locations);
   }
 };

llvm/test/tools/llvm-profdata/memprof-yaml.test

@@ -51,12 +51,14 @@ HeapProfileRecords:
 DataAccessProfiles:
   SampledRecords:
     - Symbol:          abcde
+      AccessCount:     100
       Locations:
       - FileName:      file2.h
         Line:          123
       - FileName:      file3.cpp
         Line:          456
     - Hash:            101010
+      AccessCount:     200
       Locations:
         - FileName:        file.cpp
           Line:            233