IndirectCallPromotionAnalysis.h

Go to the documentation of this file.

//===- IndirectCallPromotionAnalysis.h - Indirect call analysis -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file
/// Interface to identify indirect call promotion candidates.
///
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_ANALYSIS_INDIRECTCALLPROMOTIONANALYSIS_H
#define LLVM_ANALYSIS_INDIRECTCALLPROMOTIONANALYSIS_H
 
#include "llvm/ProfileData/InstrProf.h"
 
namespace llvm {
 
struct AnalysisOptions;
class Instruction;
class LLVMContext;
 
/// Return -icp-max-num-vtables.
LLVM_ABI unsigned getMaxNumVTableAnnotations(const LLVMContext &C);
 
// Class for identifying profitable indirect call promotion candidates when
// the indirect-call value profile metadata is available.
class ICallPromotionAnalysis {
private:
  // Allocate space to read the profile annotation.
  SmallVector<InstrProfValueData, 4> ValueDataArray;
 
  // Count is the call count for the direct-call target.
  // TotalCount is the total call count for the indirect-call callsite.
  // RemainingCount is the TotalCount minus promoted-direct-call count.
  // Return true we should promote this indirect-call target.
  bool isPromotionProfitable(const AnalysisOptions &Opts, uint64_t Count,
                             uint64_t TotalCount, uint64_t RemainingCount);
 
  // Returns the number of profitable candidates to promote for the
  // current ValueDataArray and the given \p Inst.
  uint32_t getProfitablePromotionCandidates(const AnalysisOptions &Opts,
                                            const Instruction *Inst,
                                            uint64_t TotalCount);
 
  // Noncopyable
  ICallPromotionAnalysis(const ICallPromotionAnalysis &other) = delete;
  ICallPromotionAnalysis &
  operator=(const ICallPromotionAnalysis &other) = delete;
 
public:
  ICallPromotionAnalysis() = default;
 
  /// Returns reference to array of InstrProfValueData for the given
  /// instruction \p I.
  ///
  /// The \p TotalCount and \p NumCandidates are set to the the total profile
  /// count of the indirect call \p I and the number of profitable candidates
  /// in the given array (which is sorted in reverse order of profitability).
  /// The value of \p MaxNumValueData can be used to override the max set
  /// from the -icp-max-prom option with a larger value.
  ///
  /// The returned array space is owned by this class, and overwritten on
  /// subsequent calls.
  LLVM_ABI MutableArrayRef<InstrProfValueData>
  getPromotionCandidatesForInstruction(const Instruction *I,
                                       uint64_t &TotalCount,
                                       uint32_t &NumCandidates,
                                       unsigned MaxNumValueData = 0);
};
 
} // end namespace llvm
 
#endif