[ProfileSummary] Add options to override hot and cold count thresholds.

[eraman]

Summary

The hot and cold count thresholds are derived from the summary, but for
debugging purposes it is convenient to provide the actual thresholds.

[davidxl]

lgtm

lib/Analysis/ProfileSummaryInfo.cpp

cl::desc("If the sample profile is accurate, we will mark all un-sampled "
              "we have no profile."));
 static cl::opt<unsigned> ProfileSummaryHugeWorkingSetSizeThreshold(
     "profile-summary-huge-working-set-size-threshold", cl::Hidden,
     cl::init(15000), cl::ZeroOrMore,
     cl::desc("The code working set size is considered huge if the number of"
              " blocks required to reach the -profile-summary-cutoff-hot"
              " percentile exceeds this count."));
 
+// The next two options override the counts derived from summary computation and
+// are useful for debugging purposes.
+static cl::opt<int> ProfileSummaryHotCount(
+    "profile-summary-hot-count", cl::ReallyHidden, cl::ZeroOrMore,
+    cl::desc("A fixed hot count that overrides the count derived from"
+             " profile-summary-cutoff-hot"));
+
+static cl::opt<int> ProfileSummaryColdCount(
+    "profile-summary-cold-count", cl::ReallyHidden, cl::ZeroOrMore,
+    cl::desc("A fixed cold count that overrides the count derived from"
+             " profile-summary-cutoff-cold"));
+
 // Find the summary entry for a desired percentile of counts.
 static const ProfileSummaryEntry &getEntryForPercentile(SummaryEntryVector &DS,
                                                         uint64_t Percentile) {
   auto Compare = [](const ProfileSummaryEntry &Entry, uint64_t Percentile) {
     return Entry.Cutoff < Percentile;
   };
   auto It = std::lower_bound(DS.begin(), DS.end(), Percentile, Compare);
   // The required percentile has to be <= one of the percentiles in the

 /// Compute the hot and cold thresholds.
 void ProfileSummaryInfo::computeThresholds() {
   if (!computeSummary())
     return;
   auto &DetailedSummary = Summary->getDetailedSummary();
   auto &HotEntry =
       getEntryForPercentile(DetailedSummary, ProfileSummaryCutoffHot);
   HotCountThreshold = HotEntry.MinCount;
+  if (ProfileSummaryHotCount.getNumOccurrences() > 0)
+    HotCountThreshold = ProfileSummaryHotCount;
   auto &ColdEntry =
       getEntryForPercentile(DetailedSummary, ProfileSummaryCutoffCold);
   ColdCountThreshold = ColdEntry.MinCount;
+  if (ProfileSummaryColdCount.getNumOccurrences() > 0)
+    ColdCountThreshold = ProfileSummaryColdCount;
+  assert(ColdCountThreshold <= HotCountThreshold &&
+         "Cold count threshold cannot exceed hot count threshold!");
   HasHugeWorkingSetSize =
       HotEntry.NumCounts > ProfileSummaryHugeWorkingSetSizeThreshold;
 }
 
 bool ProfileSummaryInfo::hasHugeWorkingSetSize() {
   if (!HasHugeWorkingSetSize)
     computeThresholds();
   return HasHugeWorkingSetSize && HasHugeWorkingSetSize.getValue();

test/Analysis/ProfileSummary/basic.ll

 ; RUN: opt < %s -disable-output -passes=print-profile-summary -S 2>&1 | FileCheck %s
+; RUN: opt < %s -disable-output -profile-summary-hot-count=500 -passes=print-profile-summary -S 2>&1 | FileCheck %s -check-prefixes=OVERRIDE-HOT
+; RUN: opt < %s -disable-output -profile-summary-cold-count=0 -passes=print-profile-summary -S 2>&1 | FileCheck %s -check-prefixes=OVERRIDE-COLD
+; RUN: opt < %s -disable-output -profile-summary-cold-count=200 -profile-summary-hot-count=1000 -passes=print-profile-summary -S 2>&1 | FileCheck %s -check-prefixes=OVERRIDE-BOTH
 
 define void @f1() !prof !20 {
 ; CHECK-LABEL: f1 :hot
+; OVERRIDE-HOT-LABEL: f1
+; OVERRIDE-COLD-LABEL: f1 :hot
+; OVERRIDE-BOTH-LABEL: f1
 
   ret void
 }
 
 define void @f2() !prof !21 {
 ; CHECK-LABEL: f2 :cold
+; OVERRIDE-HOT-LABEL: f2 :cold
+; OVERRIDE-COLD-LABEL: f2
+; OVERRIDE-BOTH-LABEL: f2
 
   ret void
 }
 
 define void @f3() !prof !22 {
 ; CHECK-LABEL: f3
+; OVERRIDE-HOT-LABEL: f3
+; OVERRIDE-COLD-LABEL: f3
+; OVERRIDE-BOTH-LABEL: f3
 
   ret void
 }
 
 !llvm.module.flags = !{!1}
 !20 = !{!"function_entry_count", i64 400}
 !21 = !{!"function_entry_count", i64 1}
 !22 = !{!"function_entry_count", i64 100}