76 lines · cpp
1//===- LazyBranchProbabilityInfo.cpp - Lazy Branch Probability 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-exception6//7//===----------------------------------------------------------------------===//8//9// This is an alternative analysis pass to BranchProbabilityInfoWrapperPass.10// The difference is that with this pass the branch probabilities are not11// computed when the analysis pass is executed but rather when the BPI results12// is explicitly requested by the analysis client.13//14//===----------------------------------------------------------------------===//15 16#include "llvm/Analysis/LazyBranchProbabilityInfo.h"17#include "llvm/Analysis/LoopInfo.h"18#include "llvm/Analysis/TargetLibraryInfo.h"19#include "llvm/IR/Dominators.h"20#include "llvm/InitializePasses.h"21 22using namespace llvm;23 24#define DEBUG_TYPE "lazy-branch-prob"25 26INITIALIZE_PASS_BEGIN(LazyBranchProbabilityInfoPass, DEBUG_TYPE,27 "Lazy Branch Probability Analysis", true, true)28INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)29INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)30INITIALIZE_PASS_END(LazyBranchProbabilityInfoPass, DEBUG_TYPE,31 "Lazy Branch Probability Analysis", true, true)32 33char LazyBranchProbabilityInfoPass::ID = 0;34 35LazyBranchProbabilityInfoPass::LazyBranchProbabilityInfoPass()36 : FunctionPass(ID) {37 initializeLazyBranchProbabilityInfoPassPass(*PassRegistry::getPassRegistry());38}39 40void LazyBranchProbabilityInfoPass::print(raw_ostream &OS,41 const Module *) const {42 LBPI->getCalculated().print(OS);43}44 45void LazyBranchProbabilityInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {46 // We require DT so it's available when LI is available. The LI updating code47 // asserts that DT is also present so if we don't make sure that we have DT48 // here, that assert will trigger.49 AU.addRequiredTransitive<DominatorTreeWrapperPass>();50 AU.addRequiredTransitive<LoopInfoWrapperPass>();51 AU.addRequiredTransitive<TargetLibraryInfoWrapperPass>();52 AU.setPreservesAll();53}54 55void LazyBranchProbabilityInfoPass::releaseMemory() { LBPI.reset(); }56 57bool LazyBranchProbabilityInfoPass::runOnFunction(Function &F) {58 LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();59 TargetLibraryInfo &TLI =60 getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);61 LBPI = std::make_unique<LazyBranchProbabilityInfo>(&F, &LI, &TLI);62 return false;63}64 65void LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AnalysisUsage &AU) {66 AU.addRequiredTransitive<LazyBranchProbabilityInfoPass>();67 AU.addRequiredTransitive<LoopInfoWrapperPass>();68 AU.addRequiredTransitive<TargetLibraryInfoWrapperPass>();69}70 71void llvm::initializeLazyBPIPassPass(PassRegistry &Registry) {72 INITIALIZE_PASS_DEPENDENCY(LazyBranchProbabilityInfoPass);73 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);74 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass);75}76