1//===-- SpeculateAnalyses.h --*- 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/// Contains the Analyses and Result Interpretation to select likely functions
10/// to Speculatively compile before they are called. [Purely Experimentation]
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_EXECUTIONENGINE_ORC_SPECULATEANALYSES_H
14#define LLVM_EXECUTIONENGINE_ORC_SPECULATEANALYSES_H
15
16#include "llvm/Analysis/BranchProbabilityInfo.h"
17#include "llvm/ExecutionEngine/Orc/Core.h"
18#include "llvm/ExecutionEngine/Orc/Speculation.h"
19
20#include <vector>
21
22namespace llvm {
23
24namespace orc {
25
26// Provides common code.
27class SpeculateQuery {
28protected:
29 void findCalles(const BasicBlock *, DenseSet<StringRef> &);
30 bool isStraightLine(const Function &F);
31
32public:
33 using ResultTy = Optional<DenseMap<StringRef, DenseSet<StringRef>>>;
34};
35
36// Direct calls in high frequency basic blocks are extracted.
37class BlockFreqQuery : public SpeculateQuery {
38 size_t numBBToGet(size_t);
39
40public:
41 // Find likely next executables based on IR Block Frequency
42 ResultTy operator()(Function &F);
43};
44
45// This Query generates a sequence of basic blocks which follows the order of
46// execution.
47// A handful of BB with higher block frequencies are taken, then path to entry
48// and end BB are discovered by traversing up & down the CFG.
49class SequenceBBQuery : public SpeculateQuery {
50 struct WalkDirection {
51 bool Upward = true, Downward = true;
52 // the block associated contain a call
53 bool CallerBlock = false;
54 };
55
56public:
57 using VisitedBlocksInfoTy = DenseMap<const BasicBlock *, WalkDirection>;
58 using BlockListTy = SmallVector<const BasicBlock *, 8>;
59 using BackEdgesInfoTy =
60 SmallVector<std::pair<const BasicBlock *, const BasicBlock *>, 8>;
61 using BlockFreqInfoTy =
62 SmallVector<std::pair<const BasicBlock *, uint64_t>, 8>;
63
64private:
65 std::size_t getHottestBlocks(std::size_t TotalBlocks);
66 BlockListTy rearrangeBB(const Function &, const BlockListTy &);
67 BlockListTy queryCFG(Function &, const BlockListTy &);
68 void traverseToEntryBlock(const BasicBlock *, const BlockListTy &,
69 const BackEdgesInfoTy &,
70 const BranchProbabilityInfo *,
71 VisitedBlocksInfoTy &);
72 void traverseToExitBlock(const BasicBlock *, const BlockListTy &,
73 const BackEdgesInfoTy &,
74 const BranchProbabilityInfo *,
75 VisitedBlocksInfoTy &);
76
77public:
78 ResultTy operator()(Function &F);
79};
80
81} // namespace orc
82} // namespace llvm
83
84#endif // LLVM_EXECUTIONENGINE_ORC_SPECULATEANALYSES_H
85