[llvm-profdata] Adjust profile supplementation heuristics

[xur]

Summary

(1) We now use the count size in FDO as the main factor to deal with pre-inliner.
Currently we use the number of sample records in the SampleFDO profile. But
that only counts the top-level body sample records (not including the nested
call-sites). We are seeing some big functions not being updated because of
this. I think using the count size in FDO profile is more reasonable to judge if
the function is likely to be inlined to the callers in pre-inliner.

(2) We use getMaxCount in SampleFDO rather the HeadSample to determine if
if the function is hot in SampleFDO. This is in-sync with the logic
in the compiler (also HeadSample can be 0).

[davidxl]

lgtm

llvm/test/tools/llvm-profdata/Inputs/mix_instr_small.proftext

+:ir
+foo
+7
+1
+0
+
+goo
+5
+3
+0
+0
+0
+
+moo
+9
+1
+0
+

llvm/test/tools/llvm-profdata/suppl-instr-with-sample.test

 MIX3-NEXT: Counters: 4
 MIX3-NEXT: Block counts: [3000, 1000, 2000, 500]
 
 Test foo's profile won't be adjusted because its size is smaller
 than suppl-min-size-threshold.
 RUN: llvm-profdata merge \
 RUN:     -supplement-instr-with-sample=%p/Inputs/mix_sample.proftext \
 RUN:     -suppl-min-size-threshold=2 -zero-counter-threshold=0.7 \
-RUN:     -instr-prof-cold-threshold=30 %p/Inputs/mix_instr.proftext -o %t
+RUN:     -instr-prof-cold-threshold=30 %p/Inputs/mix_instr_small.proftext -o %t
 RUN: llvm-profdata show %t -all-functions -counts | FileCheck %s --check-prefix=MIX4
 
 MIX4: foo:
 MIX4-NEXT: Hash: 0x0000000000000007
-MIX4-NEXT: Counters: 5
-MIX4-NEXT: Block counts: [12, 13, 0, 0, 0]
+MIX4-NEXT: Counters: 1
+MIX4-NEXT: Block counts: [0]
 MIX4: goo:
 MIX4-NEXT: Hash: 0x0000000000000005
 MIX4-NEXT: Counters: 3
 MIX4-NEXT: Block counts: [18446744073709551615, 18446744073709551615, 18446744073709551615]
 MIX4: moo:
 MIX4-NEXT: Hash: 0x0000000000000009
-MIX4-NEXT: Counters: 4
-MIX4-NEXT: Block counts: [3000, 1000, 2000, 500]
+MIX4-NEXT: Counters: 1
+MIX4-NEXT: Block counts: [0]
 
 Test profile summary won't be affected by -1 counter.
 RUN: llvm-profdata merge \
 RUN:     -supplement-instr-with-sample=%p/Inputs/mix_sample.proftext \
 RUN:     -suppl-min-size-threshold=0 %p/Inputs/mix_instr.proftext -o %t
 RUN: llvm-profdata show %t -detailed-summary | FileCheck %s --check-prefix=MIX5
 
 MIX5: Instrumentation level: IR

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

if (NumErrors == Inputs.size() ||
     exitWithError("no profile can be merged");
 
   writeInstrProfile(OutputFilename, OutputFormat, Contexts[0]->Writer);
 }
 
 /// The profile entry for a function in instrumentation profile.
 struct InstrProfileEntry {
   uint64_t MaxCount = 0;
+  uint64_t NumEdgeCounters = 0;
   float ZeroCounterRatio = 0.0;
   InstrProfRecord *ProfRecord;
   InstrProfileEntry(InstrProfRecord *Record);
   InstrProfileEntry() = default;
 };
 
 InstrProfileEntry::InstrProfileEntry(InstrProfRecord *Record) {
   ProfRecord = Record;
   uint64_t CntNum = Record->Counts.size();
   uint64_t ZeroCntNum = 0;
   for (size_t I = 0; I < CntNum; ++I) {
     MaxCount = std::max(MaxCount, Record->Counts[I]);
     ZeroCntNum += !Record->Counts[I];
   }
   ZeroCounterRatio = (float)ZeroCntNum / CntNum;
+  NumEdgeCounters = CntNum;
 }
 
 /// Either set all the counters in the instr profile entry \p IFE to -1
 /// in order to drop the profile or scale up the counters in \p IFP to
 /// be above hot threshold. We use the ratio of zero counters in the
 /// profile of a function to decide the profile is helpful or harmful
 /// for performance, and to choose whether to scale up or drop it.
 static void updateInstrProfileEntry(InstrProfileEntry &IFE,
uint64_t ColdInstrThreshold =
                 .MinCount;
 
   // Find hot/warm functions in sample profile which is cold in instr profile
   // and adjust the profiles of those functions in the instr profile.
   for (const auto &PD : Reader->getProfiles()) {
     auto &FContext = PD.first;
     const sampleprof::FunctionSamples &FS = PD.second;
     auto It = InstrProfileMap.find(FContext.toString());
-    if (FS.getHeadSamples() > ColdSampleThreshold &&
+    if (FS.getMaxCountInside() > ColdSampleThreshold &&
         It != InstrProfileMap.end() &&
         It->second.MaxCount <= ColdInstrThreshold &&
-        FS.getBodySamples().size() >= SupplMinSizeThreshold) {
+        It->second.NumEdgeCounters >= SupplMinSizeThreshold) {
       updateInstrProfileEntry(It->second, HotInstrThreshold,
                               ZeroCounterThreshold);
     }
   }
 }
 
 /// The main function to supplement instr profile with sample profile.
 /// \Inputs contains the instr profile. \p SampleFilename specifies the