llvm/tools/llvm-mca/BackendStatistics.h

//===--------------------- BackendStatistics.h ------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
///
/// This file implements a View named BackendStatistics that knows how to
/// collect and print a few statistics related to the retire unit.
///
/// Example:
/// ========
///
/// Retire Control Unit - number of cycles where we saw N instructions retired:
/// [# retired], [# cycles]
///  0,           9  (6.9%)
///  1,           6  (4.6%)
///  2,           1  (0.8%)
///  4,           3  (2.3%)
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_TOOLS_LLVM_MCA_BACKENDSTATISTICS_H
#define LLVM_TOOLS_LLVM_MCA_BACKENDSTATISTICS_H

#include "View.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/MC/MCSubtargetInfo.h"

namespace mca {

class BackendStatistics : public View {
  const llvm::MCSubtargetInfo &STI;

  using Histogram = llvm::DenseMap<unsigned, unsigned>;
  Histogram RetiredPerCycle;

  unsigned NumRetired;
  unsigned NumCycles;

  void updateHistograms() {
    RetiredPerCycle[NumRetired]++;
    NumRetired = 0;
  }

  void printRCUStatistics(llvm::raw_ostream &OS, const Histogram &Histogram,
                          unsigned Cycles) const;

public:
  BackendStatistics(const llvm::MCSubtargetInfo &sti)
      : STI(sti), NumRetired(0), NumCycles(0) {}

  void onInstructionEvent(const HWInstructionEvent &Event) override;

  void onCycleBegin(unsigned Cycle) override { NumCycles++; }

  void onCycleEnd(unsigned Cycle) override { updateHistograms(); }

  void printView(llvm::raw_ostream &OS) const override;
};
} // namespace mca

#endif