1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
#pragma once
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#endif
//===- LazyBranchProbabilityInfo.h - Lazy Branch Probability ----*- 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
//
//===----------------------------------------------------------------------===//
//
// This is an alternative analysis pass to BranchProbabilityInfoWrapperPass.
// The difference is that with this pass the branch probabilities are not
// computed when the analysis pass is executed but rather when the BPI results
// is explicitly requested by the analysis client.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_LAZYBRANCHPROBABILITYINFO_H
#define LLVM_ANALYSIS_LAZYBRANCHPROBABILITYINFO_H
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Pass.h"
namespace llvm {
class AnalysisUsage;
class Function;
class LoopInfo;
class TargetLibraryInfo;
/// This is an alternative analysis pass to
/// BranchProbabilityInfoWrapperPass. The difference is that with this pass the
/// branch probabilities are not computed when the analysis pass is executed but
/// rather when the BPI results is explicitly requested by the analysis client.
///
/// There are some additional requirements for any client pass that wants to use
/// the analysis:
///
/// 1. The pass needs to initialize dependent passes with:
///
/// INITIALIZE_PASS_DEPENDENCY(LazyBPIPass)
///
/// 2. Similarly, getAnalysisUsage should call:
///
/// LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU)
///
/// 3. The computed BPI should be requested with
/// getAnalysis<LazyBranchProbabilityInfoPass>().getBPI() before LoopInfo
/// could be invalidated for example by changing the CFG.
///
/// Note that it is expected that we wouldn't need this functionality for the
/// new PM since with the new PM, analyses are executed on demand.
class LazyBranchProbabilityInfoPass : public FunctionPass {
/// Wraps a BPI to allow lazy computation of the branch probabilities.
///
/// A pass that only conditionally uses BPI can uncondtionally require the
/// analysis without paying for the overhead if BPI doesn't end up being used.
class LazyBranchProbabilityInfo {
public:
LazyBranchProbabilityInfo(const Function *F, const LoopInfo *LI,
const TargetLibraryInfo *TLI)
: F(F), LI(LI), TLI(TLI) {}
/// Retrieve the BPI with the branch probabilities computed.
BranchProbabilityInfo &getCalculated() {
if (!Calculated) {
assert(F && LI && "call setAnalysis");
BPI.calculate(*F, *LI, TLI, nullptr, nullptr);
Calculated = true;
}
return BPI;
}
const BranchProbabilityInfo &getCalculated() const {
return const_cast<LazyBranchProbabilityInfo *>(this)->getCalculated();
}
private:
BranchProbabilityInfo BPI;
bool Calculated = false;
const Function *F;
const LoopInfo *LI;
const TargetLibraryInfo *TLI;
};
std::unique_ptr<LazyBranchProbabilityInfo> LBPI;
public:
static char ID;
LazyBranchProbabilityInfoPass();
/// Compute and return the branch probabilities.
BranchProbabilityInfo &getBPI() { return LBPI->getCalculated(); }
/// Compute and return the branch probabilities.
const BranchProbabilityInfo &getBPI() const { return LBPI->getCalculated(); }
void getAnalysisUsage(AnalysisUsage &AU) const override;
/// Helper for client passes to set up the analysis usage on behalf of this
/// pass.
static void getLazyBPIAnalysisUsage(AnalysisUsage &AU);
bool runOnFunction(Function &F) override;
void releaseMemory() override;
void print(raw_ostream &OS, const Module *M) const override;
};
/// Helper for client passes to initialize dependent passes for LBPI.
void initializeLazyBPIPassPass(PassRegistry &Registry);
/// Simple trait class that provides a mapping between BPI passes and the
/// corresponding BPInfo.
template <typename PassT> struct BPIPassTrait {
static PassT &getBPI(PassT *P) { return *P; }
};
template <> struct BPIPassTrait<LazyBranchProbabilityInfoPass> {
static BranchProbabilityInfo &getBPI(LazyBranchProbabilityInfoPass *P) {
return P->getBPI();
}
};
}
#endif
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif
|
