1 //===- LazyBranchProbabilityInfo.cpp - Lazy Branch Probability Analysis ---===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This is an alternative analysis pass to BranchProbabilityInfoWrapperPass.
11 // The difference is that with this pass the branch probabilities are not
12 // computed when the analysis pass is executed but rather when the BPI results
13 // is explicitly requested by the analysis client.
14 //
15 //===----------------------------------------------------------------------===//
16
17 #include "llvm/Analysis/LazyBranchProbabilityInfo.h"
18 #include "llvm/Analysis/LoopInfo.h"
19 #include "llvm/Analysis/TargetLibraryInfo.h"
20 #include "llvm/IR/Dominators.h"
21
22 using namespace llvm;
23
24 #define DEBUG_TYPE "lazy-branch-prob"
25
26 INITIALIZE_PASS_BEGIN(LazyBranchProbabilityInfoPass, DEBUG_TYPE,
27 "Lazy Branch Probability Analysis", true, true)
28 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
29 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
30 INITIALIZE_PASS_END(LazyBranchProbabilityInfoPass, DEBUG_TYPE,
31 "Lazy Branch Probability Analysis", true, true)
32
33 char LazyBranchProbabilityInfoPass::ID = 0;
34
LazyBranchProbabilityInfoPass()35 LazyBranchProbabilityInfoPass::LazyBranchProbabilityInfoPass()
36 : FunctionPass(ID) {
37 initializeLazyBranchProbabilityInfoPassPass(*PassRegistry::getPassRegistry());
38 }
39
print(raw_ostream & OS,const Module *) const40 void LazyBranchProbabilityInfoPass::print(raw_ostream &OS,
41 const Module *) const {
42 LBPI->getCalculated().print(OS);
43 }
44
getAnalysisUsage(AnalysisUsage & AU) const45 void LazyBranchProbabilityInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
46 // We require DT so it's available when LI is available. The LI updating code
47 // asserts that DT is also present so if we don't make sure that we have DT
48 // here, that assert will trigger.
49 AU.addRequired<DominatorTreeWrapperPass>();
50 AU.addRequired<LoopInfoWrapperPass>();
51 AU.addRequired<TargetLibraryInfoWrapperPass>();
52 AU.setPreservesAll();
53 }
54
releaseMemory()55 void LazyBranchProbabilityInfoPass::releaseMemory() { LBPI.reset(); }
56
runOnFunction(Function & F)57 bool LazyBranchProbabilityInfoPass::runOnFunction(Function &F) {
58 LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
59 TargetLibraryInfo &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
60 LBPI = llvm::make_unique<LazyBranchProbabilityInfo>(&F, &LI, &TLI);
61 return false;
62 }
63
getLazyBPIAnalysisUsage(AnalysisUsage & AU)64 void LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AnalysisUsage &AU) {
65 AU.addRequired<LazyBranchProbabilityInfoPass>();
66 AU.addRequired<LoopInfoWrapperPass>();
67 AU.addRequired<TargetLibraryInfoWrapperPass>();
68 }
69
initializeLazyBPIPassPass(PassRegistry & Registry)70 void llvm::initializeLazyBPIPassPass(PassRegistry &Registry) {
71 INITIALIZE_PASS_DEPENDENCY(LazyBranchProbabilityInfoPass);
72 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
73 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass);
74 }
75