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 21 using namespace llvm; 22 23 #define DEBUG_TYPE "lazy-block-freq" 24 25 INITIALIZE_PASS_BEGIN(LazyBlockFrequencyInfoPass, DEBUG_TYPE, 26 "Lazy Block Frequency Analysis", true, true) 27 INITIALIZE_PASS_DEPENDENCY(LazyBPIPass) 28 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass) 29 INITIALIZE_PASS_END(LazyBlockFrequencyInfoPass, DEBUG_TYPE, 30 "Lazy Block Frequency Analysis", true, true) 31 32 char LazyBlockFrequencyInfoPass::ID = 0; 33 34 LazyBlockFrequencyInfoPass::LazyBlockFrequencyInfoPass() : FunctionPass(ID) { 35 initializeLazyBlockFrequencyInfoPassPass(*PassRegistry::getPassRegistry()); 36 } 37 38 void LazyBlockFrequencyInfoPass::print(raw_ostream &OS, const Module *) const { 39 LBFI.getCalculated().print(OS); 40 } 41 42 void LazyBlockFrequencyInfoPass::getAnalysisUsage(AnalysisUsage &AU) const { 43 LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU); 44 // We require DT so it's available when LI is available. The LI updating code 45 // asserts that DT is also present so if we don't make sure that we have DT 46 // here, that assert will trigger. 47 AU.addRequired<DominatorTreeWrapperPass>(); 48 AU.addRequired<LoopInfoWrapperPass>(); 49 AU.setPreservesAll(); 50 } 51 52 void LazyBlockFrequencyInfoPass::releaseMemory() { LBFI.releaseMemory(); } 53 54 bool LazyBlockFrequencyInfoPass::runOnFunction(Function &F) { 55 auto &BPIPass = getAnalysis<LazyBranchProbabilityInfoPass>(); 56 LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo(); 57 LBFI.setAnalysis(&F, &BPIPass, &LI); 58 return false; 59 } 60 61 void LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AnalysisUsage &AU) { 62 LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU); 63 AU.addRequired<LazyBlockFrequencyInfoPass>(); 64 AU.addRequired<LoopInfoWrapperPass>(); 65 } 66 67 void llvm::initializeLazyBFIPassPass(PassRegistry &Registry) { 68 initializeLazyBPIPassPass(Registry); 69 INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass); 70 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass); 71 } 72