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llvm-mirror/lib/CodeGen/LazyMachineBlockFrequencyInfo.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

97 lines
3.3 KiB
C++

///===- 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"
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 = make_unique<MachineDominatorTree>();
OwnedMDT->getBase().recalculate(*MF);
MDT = OwnedMDT.get();
}
// Generate LoopInfo from it.
OwnedMLI = make_unique<MachineLoopInfo>();
OwnedMLI->getBase().analyze(MDT->getBase());
MLI = OwnedMLI.get();
}
OwnedMBFI = make_unique<MachineBlockFrequencyInfo>();
OwnedMBFI->calculate(*MF, MBPI, *MLI);
return *OwnedMBFI.get();
}
bool LazyMachineBlockFrequencyInfoPass::runOnMachineFunction(
MachineFunction &F) {
MF = &F;
return false;
}