include/llvm/Analysis/IndirectCallPromotionAnalysis.h

   1 //===- IndirectCallPromotionAnalysis.h - Indirect call analysis -*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 /// \file
   9 /// Interface to identify indirect call promotion candidates.
  10 ///
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_ANALYSIS_INDIRECTCALLPROMOTIONANALYSIS_H
  14 #define LLVM_ANALYSIS_INDIRECTCALLPROMOTIONANALYSIS_H
  15
  16 #include "llvm/ProfileData/InstrProf.h"
  17
  18 namespace llvm {
  19
  20 class Instruction;
  21
  22 // Class for identifying profitable indirect call promotion candidates when
  23 // the indirect-call value profile metadata is available.
  24 class ICallPromotionAnalysis {
  25 private:
  26   // Allocate space to read the profile annotation.
  27   std::unique_ptr<InstrProfValueData[]> ValueDataArray;
  28
  29   // Count is the call count for the direct-call target.
  30   // TotalCount is the total call count for the indirect-call callsite.
  31   // RemainingCount is the TotalCount minus promoted-direct-call count.
  32   // Return true we should promote this indirect-call target.
  33   bool isPromotionProfitable(uint64_t Count, uint64_t TotalCount,
  34                              uint64_t RemainingCount);
  35
  36   // Returns the number of profitable candidates to promote for the
  37   // current ValueDataArray and the given \p Inst.
  38   uint32_t getProfitablePromotionCandidates(const Instruction *Inst,
  39                                             uint32_t NumVals,
  40                                             uint64_t TotalCount);
  41
  42   // Noncopyable
  43   ICallPromotionAnalysis(const ICallPromotionAnalysis &other) = delete;
  44   ICallPromotionAnalysis &
  45   operator=(const ICallPromotionAnalysis &other) = delete;
  46
  47 public:
  48   ICallPromotionAnalysis();
  49
  50   /// Returns reference to array of InstrProfValueData for the given
  51   /// instruction \p I.
  52   ///
  53   /// The \p NumVals, \p TotalCount and \p NumCandidates
  54   /// are set to the number of values in the array, the total profile count
  55   /// of the indirect call \p I, and the number of profitable candidates
  56   /// in the given array (which is sorted in reverse order of profitability).
  57   ///
  58   /// The returned array space is owned by this class, and overwritten on
  59   /// subsequent calls.
  60   ArrayRef<InstrProfValueData>
  61   getPromotionCandidatesForInstruction(const Instruction *I, uint32_t &NumVals,
  62                                        uint64_t &TotalCount,
  63                                        uint32_t &NumCandidates);
  64 };
  65
  66 } // end namespace llvm
  67
  68 #endif