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///===- LazyMachineBlockFrequencyInfo.cpp - Lazy Machine Block Frequency --===//
///
/// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
/// See https://llvm.org/LICENSE.txt for license information.
/// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
///
///===---------------------------------------------------------------------===//
/// \file
/// This is an alternative analysis pass to MachineBlockFrequencyInfo. The
/// difference is that with this pass the block frequencies are not computed
/// when the analysis pass is executed but rather when the BFI result is
/// explicitly requested by the analysis client.
///
///===---------------------------------------------------------------------===//
#include "llvm/CodeGen/LazyMachineBlockFrequencyInfo.h"
#include "llvm/InitializePasses.h"
using namespace llvm;
#define DEBUG_TYPE "lazy-machine-block-freq"
INITIALIZE_PASS_BEGIN(LazyMachineBlockFrequencyInfoPass, DEBUG_TYPE,
"Lazy Machine Block Frequency Analysis", true, true)
INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
INITIALIZE_PASS_END(LazyMachineBlockFrequencyInfoPass, DEBUG_TYPE,
"Lazy Machine Block Frequency Analysis", true, true)
char LazyMachineBlockFrequencyInfoPass::ID = 0;
LazyMachineBlockFrequencyInfoPass::LazyMachineBlockFrequencyInfoPass()
: MachineFunctionPass(ID) {
initializeLazyMachineBlockFrequencyInfoPassPass(
*PassRegistry::getPassRegistry());
}
void LazyMachineBlockFrequencyInfoPass::print(raw_ostream &OS,
const Module *M) const {
getBFI().print(OS, M);
}
void LazyMachineBlockFrequencyInfoPass::getAnalysisUsage(
AnalysisUsage &AU) const {
AU.addRequired<MachineBranchProbabilityInfo>();
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
}
void LazyMachineBlockFrequencyInfoPass::releaseMemory() {
OwnedMBFI.reset();
OwnedMLI.reset();
OwnedMDT.reset();
}
MachineBlockFrequencyInfo &
LazyMachineBlockFrequencyInfoPass::calculateIfNotAvailable() const {
auto *MBFI = getAnalysisIfAvailable<MachineBlockFrequencyInfo>();
if (MBFI) {
LLVM_DEBUG(dbgs() << "MachineBlockFrequencyInfo is available\n");
return *MBFI;
}
auto &MBPI = getAnalysis<MachineBranchProbabilityInfo>();
auto *MLI = getAnalysisIfAvailable<MachineLoopInfo>();
auto *MDT = getAnalysisIfAvailable<MachineDominatorTree>();
LLVM_DEBUG(dbgs() << "Building MachineBlockFrequencyInfo on the fly\n");
LLVM_DEBUG(if (MLI) dbgs() << "LoopInfo is available\n");
if (!MLI) {
LLVM_DEBUG(dbgs() << "Building LoopInfo on the fly\n");
// First create a dominator tree.
LLVM_DEBUG(if (MDT) dbgs() << "DominatorTree is available\n");
if (!MDT) {
LLVM_DEBUG(dbgs() << "Building DominatorTree on the fly\n");
OwnedMDT = std::make_unique<MachineDominatorTree>();
OwnedMDT->getBase().recalculate(*MF);
MDT = OwnedMDT.get();
}
// Generate LoopInfo from it.
OwnedMLI = std::make_unique<MachineLoopInfo>();
OwnedMLI->getBase().analyze(MDT->getBase());
MLI = OwnedMLI.get();
}
OwnedMBFI = std::make_unique<MachineBlockFrequencyInfo>();
OwnedMBFI->calculate(*MF, MBPI, *MLI);
return *OwnedMBFI.get();
}
bool LazyMachineBlockFrequencyInfoPass::runOnMachineFunction(
MachineFunction &F) {
MF = &F;
return false;
}
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