1//===- LazyBlockFrequencyInfo.cpp - Lazy Block Frequency Analysis ---------===//
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//
9// This is an alternative analysis pass to BlockFrequencyInfoWrapperPass. The
10// difference is that with this pass the block frequencies are not computed when
11// the analysis pass is executed but rather when the BFI result is explicitly
12// requested by the analysis client.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
17#include "llvm/Analysis/LazyBranchProbabilityInfo.h"
18#include "llvm/Analysis/LoopInfo.h"
19#include "llvm/IR/Dominators.h"
20#include "llvm/InitializePasses.h"
21
22using namespace llvm;
23
24#define DEBUG_TYPE "lazy-block-freq"
25
26INITIALIZE_PASS_BEGIN(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
27 "Lazy Block Frequency Analysis", true, true)
28INITIALIZE_PASS_DEPENDENCY(LazyBPIPass)
29INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
30INITIALIZE_PASS_END(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
31 "Lazy Block Frequency Analysis", true, true)
32
33char LazyBlockFrequencyInfoPass::ID = 0;
34
35LazyBlockFrequencyInfoPass::LazyBlockFrequencyInfoPass() : FunctionPass(ID) {}
36
37void LazyBlockFrequencyInfoPass::print(raw_ostream &OS, const Module *) const {
38 LBFI.getCalculated().print(OS);
39}
40
41void LazyBlockFrequencyInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
42 LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU);
43 // We require DT so it's available when LI is available. The LI updating code
44 // asserts that DT is also present so if we don't make sure that we have DT
45 // here, that assert will trigger.
46 AU.addRequiredTransitive<DominatorTreeWrapperPass>();
47 AU.addRequiredTransitive<LoopInfoWrapperPass>();
48 AU.setPreservesAll();
49}
50
51void LazyBlockFrequencyInfoPass::releaseMemory() { LBFI.releaseMemory(); }
52
53bool LazyBlockFrequencyInfoPass::runOnFunction(Function &F) {
54 auto &BPIPass = getAnalysis<LazyBranchProbabilityInfoPass>();
55 LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
56 LBFI.setAnalysis(F: &F, BPIPass: &BPIPass, LI: &LI);
57 return false;
58}
59
60void LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AnalysisUsage &AU) {
61 LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU);
62 AU.addRequiredTransitive<LazyBlockFrequencyInfoPass>();
63 AU.addRequiredTransitive<LoopInfoWrapperPass>();
64}
65
66void llvm::initializeLazyBFIPassPass(PassRegistry &Registry) {
67 initializeLazyBPIPassPass(Registry);
68 INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass);
69 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
70}
71