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 22 using namespace llvm; 23 24 #define DEBUG_TYPE "lazy-block-freq" 25 26 INITIALIZE_PASS_BEGIN(LazyBlockFrequencyInfoPass, DEBUG_TYPE, 27 "Lazy Block Frequency Analysis", true, true) 28 INITIALIZE_PASS_DEPENDENCY(LazyBPIPass) 29 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass) 30 INITIALIZE_PASS_END(LazyBlockFrequencyInfoPass, DEBUG_TYPE, 31 "Lazy Block Frequency Analysis", true, true) 32 33 char LazyBlockFrequencyInfoPass::ID = 0; 34 35 LazyBlockFrequencyInfoPass::LazyBlockFrequencyInfoPass() : FunctionPass(ID) {} 36 37 void LazyBlockFrequencyInfoPass::print(raw_ostream &OS, const Module *) const { 38 LBFI.getCalculated().print(OS); 39 } 40 41 void 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 51 void LazyBlockFrequencyInfoPass::releaseMemory() { LBFI.releaseMemory(); } 52 53 bool LazyBlockFrequencyInfoPass::runOnFunction(Function &F) { 54 auto &BPIPass = getAnalysis<LazyBranchProbabilityInfoPass>(); 55 LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo(); 56 LBFI.setAnalysis(&F, &BPIPass, &LI); 57 return false; 58 } 59 60 void LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AnalysisUsage &AU) { 61 LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU); 62 AU.addRequiredTransitive<LazyBlockFrequencyInfoPass>(); 63 AU.addRequiredTransitive<LoopInfoWrapperPass>(); 64 } 65 66 void llvm::initializeLazyBFIPassPass(PassRegistry &Registry) { 67 initializeLazyBPIPassPass(Registry); 68 INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass); 69 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass); 70 } 71