[llvm-exegesis][NFC] remove runAndMeasure

[aidengrossman]

Summary

This completes the FIXME listed in FunctionExecutor in regards to
deprecating this function. It simply makes the appropriate call into
runAndSample and grabs the first counter value. This patch completely
removes the function, moving that logic into the callers (currently only
uopsBenchmarkRunner). This makes creating new FunctionExecutors easier
as an implementation no longer needs to worry about this detail.

llvm/tools/llvm-exegesis/lib/BenchmarkRunner.h

private:
     char *const AlignedPtr;
   };
 
   // A helper to measure counters while executing a function in a sandboxed
   // context.
   class FunctionExecutor {
   public:
     virtual ~FunctionExecutor();
-    // FIXME deprecate this.
-    virtual Expected<int64_t> runAndMeasure(const char *Counters) const = 0;
 
     virtual Expected<llvm::SmallVector<int64_t, 4>>
     runAndSample(const char *Counters) const = 0;
   };
 
 protected:
   const LLVMState &State;
   const Benchmark::ModeE Mode;

llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp

 public:
   FunctionExecutorImpl(const LLVMState &State,
                        object::OwningBinary<object::ObjectFile> Obj,
                        BenchmarkRunner::ScratchSpace *Scratch)
       : State(State), Function(State.createTargetMachine(), std::move(Obj)),
         Scratch(Scratch) {}
 
 private:
-  Expected<int64_t> runAndMeasure(const char *Counters) const override {
-    auto ResultOrError = runAndSample(Counters);
-    if (ResultOrError)
-      return ResultOrError.get()[0];
-    return ResultOrError.takeError();
-  }
-
   static void
   accumulateCounterValues(const llvm::SmallVector<int64_t, 4> &NewValues,
                           llvm::SmallVector<int64_t, 4> *Result) {
     const size_t NumValues = std::max(NewValues.size(), Result->size());
     if (NumValues > Result->size())
       Result->resize(NumValues, 0);
     for (size_t I = 0, End = NewValues.size(); I < End; ++I)
       (*Result)[I] += NewValues[I];

llvm/tools/llvm-exegesis/lib/UopsBenchmarkRunner.cpp

UopsBenchmarkRunner::runMeasurements(const FunctionExecutor &Executor) const {
   std::vector<BenchmarkMeasure> Result;
   const PfmCountersInfo &PCI = State.getPfmCounters();
   // Uops per port.
   for (const auto *IssueCounter = PCI.IssueCounters,
                   *IssueCounterEnd = PCI.IssueCounters + PCI.NumIssueCounters;
        IssueCounter != IssueCounterEnd; ++IssueCounter) {
     if (!IssueCounter->Counter)
       continue;
-    auto ExpectedCounterValue = Executor.runAndMeasure(IssueCounter->Counter);
+    auto ExpectedCounterValue = Executor.runAndSample(IssueCounter->Counter);
     if (!ExpectedCounterValue)
       return ExpectedCounterValue.takeError();
     Result.push_back(BenchmarkMeasure::Create(IssueCounter->ProcResName,
-                                              *ExpectedCounterValue));
+                                              (*ExpectedCounterValue)[0]));
   }
   // NumMicroOps.
   if (const char *const UopsCounter = PCI.UopsCounter) {
-    auto ExpectedCounterValue = Executor.runAndMeasure(UopsCounter);
+    auto ExpectedCounterValue = Executor.runAndSample(UopsCounter);
     if (!ExpectedCounterValue)
       return ExpectedCounterValue.takeError();
     Result.push_back(
-        BenchmarkMeasure::Create("NumMicroOps", *ExpectedCounterValue));
+        BenchmarkMeasure::Create("NumMicroOps", (*ExpectedCounterValue)[0]));
   }
   return std::move(Result);
 }
 
 } // namespace exegesis
 } // namespace llvm