[llvm-profdata] Allow overlap/similarity comparison to use custom hot threshold cutoff

[wenlei]

Summary

Allow overlap/similarity comparison to use custom hot threshold cutoff, instead of using hard coded 990000 as hot cutoff.

[hoy]

lgtm

llvm/tools/llvm-profdata/llvm-profdata.cpp

std::error_code SampleOverlapAggregator::loadProfiles() {
   if (BaseReader->profileIsProbeBased() != TestReader->profileIsProbeBased())
     exitWithError(
         "cannot compare probe-based profile with non-probe-based profile");
   if (BaseReader->profileIsCS() != TestReader->profileIsCS())
     exitWithError("cannot compare CS profile with non-CS profile");
 
   // Load BaseHotThreshold and TestHotThreshold as 99-percentile threshold in
   // profile summary.
-  const uint64_t HotCutoff = 990000;
   ProfileSummary &BasePS = BaseReader->getSummary();
-  for (const auto &SummaryEntry : BasePS.getDetailedSummary()) {
-    if (SummaryEntry.Cutoff == HotCutoff) {
-      BaseHotThreshold = SummaryEntry.MinCount;
-      break;
-    }
-  }
-
   ProfileSummary &TestPS = TestReader->getSummary();
-  for (const auto &SummaryEntry : TestPS.getDetailedSummary()) {
-    if (SummaryEntry.Cutoff == HotCutoff) {
-      TestHotThreshold = SummaryEntry.MinCount;
-      break;
-    }
-  }
+  BaseHotThreshold =
+      ProfileSummaryBuilder::getHotCountThreshold(BasePS.getDetailedSummary());
+  TestHotThreshold =
+      ProfileSummaryBuilder::getHotCountThreshold(TestPS.getDetailedSummary());
+
   return std::error_code();
 }
 
 void overlapSampleProfile(const std::string &BaseFilename,
                           const std::string &TestFilename,
                           const OverlapFuncFilters &FuncFilter,
                           uint64_t SimilarityCutoff, raw_fd_ostream &OS) {
   using namespace sampleprof;