[PGO] Text format profile reader needs to clear the value profile

[xur]

Summary

Reset the ValueData for each function to avoid using the ones in
the previous function.

[davidxl]

lib/ProfileData/InstrProfReader.cpp

247

Add a Clear() member function to do counter reset for both edge and value counts.

[xur]

Integrated David's review comments.

[davidxl]

lgtm

include/llvm/ProfileData/InstrProf.h

struct InstrProfRecord {
   void sortValueData() {
     for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind) {
       std::vector<InstrProfValueSiteRecord> &SiteRecords =
           getValueSitesForKind(Kind);
       for (auto &SR : SiteRecords)
         SR.sortByCount();
     }
   }
+
+  /// Clear value data entries and edge counters.
+  void Clear() {
+    Counts.clear();
+    clearValueData();
+  }
+
   /// Clear value data entries
   void clearValueData() {
     for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
       getValueSitesForKind(Kind).clear();
   }
 
   /// Get the error contained within the record's soft error counter.
   Error takeError() { return SIPE.takeError(); }

lib/ProfileData/InstrProfReader.cpp

Error TextInstrProfReader::readNextRecord(InstrProfRecord &Record) {
   if (Line.is_at_end())
     return error(instrprof_error::truncated);
   if ((Line++)->getAsInteger(10, NumCounters))
     return error(instrprof_error::malformed);
   if (NumCounters == 0)
     return error(instrprof_error::malformed);
 
   // Read each counter and fill our internal storage with the values.
-  Record.Counts.clear();
+  Record.Clear();
   Record.Counts.reserve(NumCounters);
   for (uint64_t I = 0; I < NumCounters; ++I) {
     if (Line.is_at_end())
       return error(instrprof_error::truncated);
     uint64_t Count;
     if ((Line++)->getAsInteger(10, Count))
       return error(instrprof_error::malformed);
     Record.Counts.push_back(Count);
   }
 
   // Check if value profile data exists and read it if so.
   if (Error E = readValueProfileData(Record))
     return E;
 
   // This is needed to avoid two pass parsing because llvm-profdata
   // does dumping while reading.
   Symtab->finalizeSymtab();
   return success();
 }

test/tools/llvm-profdata/value-prof.proftext

 #IC-NEXT: [ 2, foo2, 20000 ]
 
 #ICTEXT: foo:100
 #ICTEXT-NEXT: foo2:1000
 #ICTEXT-NEXT: 1
 #ICTEXT-NEXT: foo2:20000
 #
 
+bar
+# Func Hash:
+10
+# Num Counters:
+2
+# Counter Values:
+999000
+359800
+
 #ICSUM: Total Number of Indirect Call Sites : 3
 #ICSUM: Total Number of Sites With Values : 2
 #ICSUM: Total Number of Profiled Values : 3
 #ICSUM: NumTargets, SiteCount
 #ICSUM  1, 1
 #ICSUM  2, 1