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
69