[llvm-exegesis] Add support for measuring NumMicroOps.

Summary:
Example output for vzeroall:

---
mode:            uops
key:
  instructions:
    - 'VZEROALL'
  config:          ''
  register_initial_values:
cpu_name:        haswell
llvm_triple:     x86_64-unknown-linux-gnu
num_repetitions: 10000
measurements:
  - { debug_string: HWPort0, value: 0.0006, per_snippet_value: 0.0006,
      key: '3' }
  - { debug_string: HWPort1, value: 0.0011, per_snippet_value: 0.0011,
      key: '4' }
  - { debug_string: HWPort2, value: 0.0004, per_snippet_value: 0.0004,
      key: '5' }
  - { debug_string: HWPort3, value: 0.0018, per_snippet_value: 0.0018,
      key: '6' }
  - { debug_string: HWPort4, value: 0.0002, per_snippet_value: 0.0002,
      key: '7' }
  - { debug_string: HWPort5, value: 1.0019, per_snippet_value: 1.0019,
      key: '8' }
  - { debug_string: HWPort6, value: 1.0033, per_snippet_value: 1.0033,
      key: '9' }
  - { debug_string: HWPort7, value: 0.0001, per_snippet_value: 0.0001,
      key: '10' }
  - { debug_string: NumMicroOps, value: 20.0069, per_snippet_value: 20.0069,
      key: NumMicroOps }
error:           ''
info:            ''
assembled_snippet: C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C3
...

Reviewers: gchatelet

Subscribers: tschuett, RKSimon, andreadb, llvm-commits

Differential Revision: https://reviews.llvm.org/D52539

llvm-svn: 343094
diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
index e4e29ef..0fcf4e9 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
@@ -41,6 +41,10 @@
 };
 
 struct BenchmarkMeasure {
+  // A helper to create an unscaled BenchmarkMeasure.
+  static BenchmarkMeasure Create(std::string Key, double Value) {
+    return {Key, Value, Value, Key};
+  }
   std::string Key;
   // This is the per-instruction value, i.e. measured quantity scaled per
   // instruction.
@@ -48,6 +52,7 @@
   // This is the per-snippet value, i.e. measured quantity for one repetition of
   // the whole snippet.
   double PerSnippetValue;
+  // FIXME: remove, use `Key` instead.
   std::string DebugString;
 };
 
diff --git a/llvm/tools/llvm-exegesis/lib/Latency.cpp b/llvm/tools/llvm-exegesis/lib/Latency.cpp
index 3c402c4..9eeb264 100644
--- a/llvm/tools/llvm-exegesis/lib/Latency.cpp
+++ b/llvm/tools/llvm-exegesis/lib/Latency.cpp
@@ -130,8 +130,7 @@
     if (Value < MinLatency)
       MinLatency = Value;
   }
-  return {{"latency", static_cast<double>(MinLatency),
-           static_cast<double>(MinLatency), ""}};
+  return {BenchmarkMeasure::Create("latency", MinLatency)};
 }
 
 } // namespace exegesis
diff --git a/llvm/tools/llvm-exegesis/lib/Uops.cpp b/llvm/tools/llvm-exegesis/lib/Uops.cpp
index dbecbfe..d7ac880 100644
--- a/llvm/tools/llvm-exegesis/lib/Uops.cpp
+++ b/llvm/tools/llvm-exegesis/lib/Uops.cpp
@@ -255,23 +255,18 @@
                                      ScratchSpace &Scratch) const {
   const auto &SchedModel = State.getSubtargetInfo().getSchedModel();
 
-  std::vector<BenchmarkMeasure> Result;
-  for (unsigned ProcResIdx = 1;
-       ProcResIdx < SchedModel.getNumProcResourceKinds(); ++ProcResIdx) {
-    const char *const PfmCounters = SchedModel.getExtraProcessorInfo()
-                                        .PfmCounters.IssueCounters[ProcResIdx];
-    if (!PfmCounters)
-      continue;
+  const auto RunMeasurement = [&Function,
+                               &Scratch](const char *const Counters) {
     // We sum counts when there are several counters for a single ProcRes
     // (e.g. P23 on SandyBridge).
     int64_t CounterValue = 0;
     llvm::SmallVector<llvm::StringRef, 2> CounterNames;
-    llvm::StringRef(PfmCounters).split(CounterNames, ',');
+    llvm::StringRef(Counters).split(CounterNames, ',');
     for (const auto &CounterName : CounterNames) {
       pfm::PerfEvent UopPerfEvent(CounterName);
       if (!UopPerfEvent.valid())
         llvm::report_fatal_error(
-            llvm::Twine("invalid perf event ").concat(PfmCounters));
+            llvm::Twine("invalid perf event ").concat(Counters));
       pfm::Counter Counter(UopPerfEvent);
       Scratch.clear();
       Counter.start();
@@ -279,10 +274,24 @@
       Counter.stop();
       CounterValue += Counter.read();
     }
-    Result.push_back({llvm::itostr(ProcResIdx),
-                      static_cast<double>(CounterValue),
-                      static_cast<double>(CounterValue),
-                      SchedModel.getProcResource(ProcResIdx)->Name});
+    return CounterValue;
+  };
+
+  std::vector<BenchmarkMeasure> Result;
+  const auto& PfmCounters = SchedModel.getExtraProcessorInfo().PfmCounters;
+  // Uops per port.
+  for (unsigned ProcResIdx = 1;
+       ProcResIdx < SchedModel.getNumProcResourceKinds(); ++ProcResIdx) {
+    const char *const Counters = PfmCounters.IssueCounters[ProcResIdx];
+    if (!Counters)
+      continue;
+    const double CounterValue = RunMeasurement(Counters);
+    Result.push_back(BenchmarkMeasure::Create(SchedModel.getProcResource(ProcResIdx)->Name, CounterValue));
+  }
+  // NumMicroOps.
+  if (const char *const UopsCounter = PfmCounters.UopsCounter) {
+    const double CounterValue = RunMeasurement(UopsCounter);
+    Result.push_back(BenchmarkMeasure::Create("NumMicroOps", CounterValue));
   }
   return Result;
 }