LazyBlockFrequencyInfo.cpp revision 360784
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 initializeLazyBlockFrequencyInfoPassPass(*PassRegistry::getPassRegistry()); 37} 38 39void LazyBlockFrequencyInfoPass::print(raw_ostream &OS, const Module *) const { 40 LBFI.getCalculated().print(OS); 41} 42 43void 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.addRequired<DominatorTreeWrapperPass>(); 49 AU.addRequired<LoopInfoWrapperPass>(); 50 AU.setPreservesAll(); 51} 52 53void LazyBlockFrequencyInfoPass::releaseMemory() { LBFI.releaseMemory(); } 54 55bool 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 62void LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AnalysisUsage &AU) { 63 LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU); 64 AU.addRequired<LazyBlockFrequencyInfoPass>(); 65 AU.addRequired<LoopInfoWrapperPass>(); 66} 67 68void llvm::initializeLazyBFIPassPass(PassRegistry &Registry) { 69 initializeLazyBPIPassPass(Registry); 70 INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass); 71 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass); 72} 73