llvm/Analysis/IndirectCallPromotionAnalysis.h

0001 //===- IndirectCallPromotionAnalysis.h - Indirect call analysis -*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008 /// \file
0009 /// Interface to identify indirect call promotion candidates.
0010 ///
0011 //===----------------------------------------------------------------------===//
0012
0013 #ifndef LLVM_ANALYSIS_INDIRECTCALLPROMOTIONANALYSIS_H
0014 #define LLVM_ANALYSIS_INDIRECTCALLPROMOTIONANALYSIS_H
0015
0016 #include "llvm/ProfileData/InstrProf.h"
0017
0018 namespace llvm {
0019
0020 class Instruction;
0021
0022 // Class for identifying profitable indirect call promotion candidates when
0023 // the indirect-call value profile metadata is available.
0024 class ICallPromotionAnalysis {
0025 private:
0026   // Allocate space to read the profile annotation.
0027   SmallVector<InstrProfValueData, 4> ValueDataArray;
0028
0029   // Count is the call count for the direct-call target.
0030   // TotalCount is the total call count for the indirect-call callsite.
0031   // RemainingCount is the TotalCount minus promoted-direct-call count.
0032   // Return true we should promote this indirect-call target.
0033   bool isPromotionProfitable(uint64_t Count, uint64_t TotalCount,
0034                              uint64_t RemainingCount);
0035
0036   // Returns the number of profitable candidates to promote for the
0037   // current ValueDataArray and the given \p Inst.
0038   uint32_t getProfitablePromotionCandidates(const Instruction *Inst,
0039                                             uint64_t TotalCount);
0040
0041   // Noncopyable
0042   ICallPromotionAnalysis(const ICallPromotionAnalysis &other) = delete;
0043   ICallPromotionAnalysis &
0044   operator=(const ICallPromotionAnalysis &other) = delete;
0045
0046 public:
0047   ICallPromotionAnalysis() = default;
0048
0049   /// Returns reference to array of InstrProfValueData for the given
0050   /// instruction \p I.
0051   ///
0052   /// The \p TotalCount and \p NumCandidates are set to the the total profile
0053   /// count of the indirect call \p I and the number of profitable candidates
0054   /// in the given array (which is sorted in reverse order of profitability).
0055   ///
0056   /// The returned array space is owned by this class, and overwritten on
0057   /// subsequent calls.
0058   MutableArrayRef<InstrProfValueData> getPromotionCandidatesForInstruction(
0059       const Instruction *I, uint64_t &TotalCount, uint32_t &NumCandidates);
0060 };
0061
0062 } // end namespace llvm
0063
0064 #endif