[ProfileData] Use default member initializations (NFC)

llvm/include/llvm/ProfileData/InstrProf.h

@@ -1184,21 +1184,21 @@ inline uint64_t ComputeHash(StringRef K) { return ComputeHash(HashType, K); }
 // data file in indexed-format. Please update llvm/docs/InstrProfileFormat.rst
 // as appropriate when updating the indexed profile format.
 struct Header {
-  uint64_t Magic;
+  uint64_t Magic = IndexedInstrProf::Magic;
   // The lower 32 bits specify the version of the indexed profile.
   // The most significant 32 bits are reserved to specify the variant types of
   // the profile.
-  uint64_t Version;
-  uint64_t Unused; // Becomes unused since version 4
-  uint64_t HashType;
+  uint64_t Version = 0;
+  uint64_t Unused = 0; // Becomes unused since version 4
+  uint64_t HashType = static_cast<uint64_t>(IndexedInstrProf::HashType);
   // This field records the offset of this hash table's metadata (i.e., the
   // number of buckets and entries), which follows right after the payload of
   // the entire hash table.
-  uint64_t HashOffset;
-  uint64_t MemProfOffset;
-  uint64_t BinaryIdOffset;
-  uint64_t TemporalProfTracesOffset;
-  uint64_t VTableNamesOffset;
+  uint64_t HashOffset = 0;
+  uint64_t MemProfOffset = 0;
+  uint64_t BinaryIdOffset = 0;
+  uint64_t TemporalProfTracesOffset = 0;
+  uint64_t VTableNamesOffset = 0;
   // New fields should only be added at the end to ensure that the size
   // computation is correct. The methods below need to be updated to ensure that
   // the new field is read correctly.

llvm/lib/ProfileData/InstrProfWriter.cpp

@@ -682,7 +682,6 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {
 
   // Write the header.
   IndexedInstrProf::Header Header;
-  Header.Magic = IndexedInstrProf::Magic;
   Header.Version = WritePrevVersion
                        ? IndexedInstrProf::ProfVersion::Version11
                        : IndexedInstrProf::ProfVersion::CurrentVersion;
@@ -706,14 +705,6 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {
   if (static_cast<bool>(ProfileKind & InstrProfKind::TemporalProfile))
     Header.Version |= VARIANT_MASK_TEMPORAL_PROF;
 
-  Header.Unused = 0;
-  Header.HashType = static_cast<uint64_t>(IndexedInstrProf::HashType);
-  Header.HashOffset = 0;
-  Header.MemProfOffset = 0;
-  Header.BinaryIdOffset = 0;
-  Header.TemporalProfTracesOffset = 0;
-  Header.VTableNamesOffset = 0;
-
   const uint64_t BackPatchStartOffset =
       writeHeader(Header, WritePrevVersion, OS);