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 initializeLazyBlockFrequencyInfoPassPass(*PassRegistry::getPassRegistry()); 37 } 38 39 void LazyBlockFrequencyInfoPass::print(raw_ostream &OS, const Module *) const { 40 LBFI.getCalculated().print(OS); 41 } 42 43 void LazyBlockFrequencyInfoPass::getAnalysisUsage(AnalysisUsage &AU) const { 44 LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU); 45 // We require DT so it's available when LI is available. The LI updating code 46 // asserts that DT is also present so if we don't make sure that we have DT 47 // here, that assert will trigger. 48 AU.addRequiredTransitive<DominatorTreeWrapperPass>(); 49 AU.addRequiredTransitive<LoopInfoWrapperPass>(); 50 AU.setPreservesAll(); 51 } 52 53 void LazyBlockFrequencyInfoPass::releaseMemory() { LBFI.releaseMemory(); } 54 55 bool LazyBlockFrequencyInfoPass::runOnFunction(Function &F) { 56 auto &BPIPass = getAnalysis<LazyBranchProbabilityInfoPass>(); 57 LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo(); 58 LBFI.setAnalysis(&F, &BPIPass, &LI); 59 return false; 60 } 61 62 void LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AnalysisUsage &AU) { 63 LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU); 64 AU.addRequiredTransitive<LazyBlockFrequencyInfoPass>(); 65 AU.addRequiredTransitive<LoopInfoWrapperPass>(); 66 } 67 68 void llvm::initializeLazyBFIPassPass(PassRegistry &Registry) { 69 initializeLazyBPIPassPass(Registry); 70 INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass); 71 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass); 72 } 73