[llvm-exegesis] Allow measuring several instructions in a single run.

Summary:
We try to recover gracefully on instructions that would crash the
program.

This includes some refactoring of runMeasurement() implementations.

Reviewers: gchatelet

Subscribers: tschuett, llvm-commits

Differential Revision: https://reviews.llvm.org/D53371

llvm-svn: 344695

1 files changed, 12 insertions, 31 deletions

diff --git a/llvm/tools/llvm-exegesis/lib/Uops.cpp b/llvm/tools/llvm-exegesis/lib/Uops.cpp
index d8065adbdb2..50be707feb2 100644
--- a/llvm/tools/llvm-exegesis/lib/Uops.cpp
+++ b/llvm/tools/llvm-exegesis/lib/Uops.cpp
@@ -12,7 +12,6 @@
 #include "Assembler.h"
 #include "BenchmarkRunner.h"
 #include "MCInstrDescView.h"
-#include "PerfHelper.h"
 #include "Target.h"
 
 // FIXME: Load constants into registers (e.g. with fld1) to not break
@@ -221,33 +220,10 @@ UopsSnippetGenerator::generateCodeTemplates(const Instruction &Instr) const {
   return getSingleton(std::move(CT));
 }
 
-std::vector<BenchmarkMeasure>
-UopsBenchmarkRunner::runMeasurements(const ExecutableFunction &Function,
-                                     ScratchSpace &Scratch) const {
+llvm::Expected<std::vector<BenchmarkMeasure>>
+UopsBenchmarkRunner::runMeasurements(const FunctionExecutor &Executor) const {
   const auto &SchedModel = State.getSubtargetInfo().getSchedModel();
 
-  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(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(Counters));
-      pfm::Counter Counter(UopPerfEvent);
-      Scratch.clear();
-      Counter.start();
-      Function(Scratch.ptr());
-      Counter.stop();
-      CounterValue += Counter.read();
-    }
-    return CounterValue;
-  };
-
   std::vector<BenchmarkMeasure> Result;
   const auto &PfmCounters = SchedModel.getExtraProcessorInfo().PfmCounters;
   // Uops per port.
@@ -256,16 +232,21 @@ UopsBenchmarkRunner::runMeasurements(const ExecutableFunction &Function,
     const char *const Counters = PfmCounters.IssueCounters[ProcResIdx];
     if (!Counters)
       continue;
-    const double CounterValue = RunMeasurement(Counters);
+    auto ExpectedCounterValue = Executor.runAndMeasure(Counters);
+    if (!ExpectedCounterValue)
+      return ExpectedCounterValue.takeError();
     Result.push_back(BenchmarkMeasure::Create(
-        SchedModel.getProcResource(ProcResIdx)->Name, CounterValue));
+        SchedModel.getProcResource(ProcResIdx)->Name, *ExpectedCounterValue));
   }
   // NumMicroOps.
   if (const char *const UopsCounter = PfmCounters.UopsCounter) {
-    const double CounterValue = RunMeasurement(UopsCounter);
-    Result.push_back(BenchmarkMeasure::Create("NumMicroOps", CounterValue));
+    auto ExpectedCounterValue = Executor.runAndMeasure(UopsCounter);
+    if (!ExpectedCounterValue)
+      return ExpectedCounterValue.takeError();
+    Result.push_back(
+        BenchmarkMeasure::Create("NumMicroOps", *ExpectedCounterValue));
   }
-  return Result;
+  return std::move(Result);
 }
 
 constexpr const size_t UopsSnippetGenerator::kMinNumDifferentAddresses;