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llvm-for-llvmta/lib/CodeGen/MachineBlockFrequencyInfo.cpp

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//===- MachineBlockFrequencyInfo.cpp - MBB Frequency Analysis -------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Loops should be simplified before this analysis.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/iterator.h"
#include "llvm/Analysis/BlockFrequencyInfoImpl.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/GraphWriter.h"
#include <string>
using namespace llvm;
#define DEBUG_TYPE "machine-block-freq"
static cl::opt<GVDAGType> ViewMachineBlockFreqPropagationDAG(
"view-machine-block-freq-propagation-dags", cl::Hidden,
cl::desc("Pop up a window to show a dag displaying how machine block "
"frequencies propagate through the CFG."),
cl::values(clEnumValN(GVDT_None, "none", "do not display graphs."),
clEnumValN(GVDT_Fraction, "fraction",
"display a graph using the "
"fractional block frequency representation."),
clEnumValN(GVDT_Integer, "integer",
"display a graph using the raw "
"integer fractional block frequency representation."),
clEnumValN(GVDT_Count, "count", "display a graph using the real "
"profile count if available.")));
// Similar option above, but used to control BFI display only after MBP pass
cl::opt<GVDAGType> ViewBlockLayoutWithBFI(
"view-block-layout-with-bfi", cl::Hidden,
cl::desc(
"Pop up a window to show a dag displaying MBP layout and associated "
"block frequencies of the CFG."),
cl::values(clEnumValN(GVDT_None, "none", "do not display graphs."),
clEnumValN(GVDT_Fraction, "fraction",
"display a graph using the "
"fractional block frequency representation."),
clEnumValN(GVDT_Integer, "integer",
"display a graph using the raw "
"integer fractional block frequency representation."),
clEnumValN(GVDT_Count, "count",
"display a graph using the real "
"profile count if available.")));
// Command line option to specify the name of the function for CFG dump
// Defined in Analysis/BlockFrequencyInfo.cpp: -view-bfi-func-name=
extern cl::opt<std::string> ViewBlockFreqFuncName;
// Command line option to specify hot frequency threshold.
// Defined in Analysis/BlockFrequencyInfo.cpp: -view-hot-freq-perc=
extern cl::opt<unsigned> ViewHotFreqPercent;
static cl::opt<bool> PrintMachineBlockFreq(
"print-machine-bfi", cl::init(false), cl::Hidden,
cl::desc("Print the machine block frequency info."));
// Command line option to specify the name of the function for block frequency
// dump. Defined in Analysis/BlockFrequencyInfo.cpp.
extern cl::opt<std::string> PrintBlockFreqFuncName;
static GVDAGType getGVDT() {
if (ViewBlockLayoutWithBFI != GVDT_None)
return ViewBlockLayoutWithBFI;
return ViewMachineBlockFreqPropagationDAG;
}
namespace llvm {
template <> struct GraphTraits<MachineBlockFrequencyInfo *> {
using NodeRef = const MachineBasicBlock *;
using ChildIteratorType = MachineBasicBlock::const_succ_iterator;
using nodes_iterator = pointer_iterator<MachineFunction::const_iterator>;
static NodeRef getEntryNode(const MachineBlockFrequencyInfo *G) {
return &G->getFunction()->front();
}
static ChildIteratorType child_begin(const NodeRef N) {
return N->succ_begin();
}
static ChildIteratorType child_end(const NodeRef N) { return N->succ_end(); }
static nodes_iterator nodes_begin(const MachineBlockFrequencyInfo *G) {
return nodes_iterator(G->getFunction()->begin());
}
static nodes_iterator nodes_end(const MachineBlockFrequencyInfo *G) {
return nodes_iterator(G->getFunction()->end());
}
};
using MBFIDOTGraphTraitsBase =
BFIDOTGraphTraitsBase<MachineBlockFrequencyInfo,
MachineBranchProbabilityInfo>;
template <>
struct DOTGraphTraits<MachineBlockFrequencyInfo *>
: public MBFIDOTGraphTraitsBase {
const MachineFunction *CurFunc = nullptr;
DenseMap<const MachineBasicBlock *, int> LayoutOrderMap;
explicit DOTGraphTraits(bool isSimple = false)
: MBFIDOTGraphTraitsBase(isSimple) {}
std::string getNodeLabel(const MachineBasicBlock *Node,
const MachineBlockFrequencyInfo *Graph) {
int layout_order = -1;
// Attach additional ordering information if 'isSimple' is false.
if (!isSimple()) {
const MachineFunction *F = Node->getParent();
if (!CurFunc || F != CurFunc) {
if (CurFunc)
LayoutOrderMap.clear();
CurFunc = F;
int O = 0;
for (auto MBI = F->begin(); MBI != F->end(); ++MBI, ++O) {
LayoutOrderMap[&*MBI] = O;
}
}
layout_order = LayoutOrderMap[Node];
}
return MBFIDOTGraphTraitsBase::getNodeLabel(Node, Graph, getGVDT(),
layout_order);
}
std::string getNodeAttributes(const MachineBasicBlock *Node,
const MachineBlockFrequencyInfo *Graph) {
return MBFIDOTGraphTraitsBase::getNodeAttributes(Node, Graph,
ViewHotFreqPercent);
}
std::string getEdgeAttributes(const MachineBasicBlock *Node, EdgeIter EI,
const MachineBlockFrequencyInfo *MBFI) {
return MBFIDOTGraphTraitsBase::getEdgeAttributes(
Node, EI, MBFI, MBFI->getMBPI(), ViewHotFreqPercent);
}
};
} // end namespace llvm
INITIALIZE_PASS_BEGIN(MachineBlockFrequencyInfo, DEBUG_TYPE,
"Machine Block Frequency Analysis", true, true)
INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
INITIALIZE_PASS_END(MachineBlockFrequencyInfo, DEBUG_TYPE,
"Machine Block Frequency Analysis", true, true)
char MachineBlockFrequencyInfo::ID = 0;
MachineBlockFrequencyInfo::MachineBlockFrequencyInfo()
: MachineFunctionPass(ID) {
initializeMachineBlockFrequencyInfoPass(*PassRegistry::getPassRegistry());
}
MachineBlockFrequencyInfo::MachineBlockFrequencyInfo(
MachineFunction &F,
MachineBranchProbabilityInfo &MBPI,
MachineLoopInfo &MLI) : MachineFunctionPass(ID) {
calculate(F, MBPI, MLI);
}
MachineBlockFrequencyInfo::~MachineBlockFrequencyInfo() = default;
void MachineBlockFrequencyInfo::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<MachineBranchProbabilityInfo>();
AU.addRequired<MachineLoopInfo>();
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
}
void MachineBlockFrequencyInfo::calculate(
const MachineFunction &F, const MachineBranchProbabilityInfo &MBPI,
const MachineLoopInfo &MLI) {
if (!MBFI)
MBFI.reset(new ImplType);
MBFI->calculate(F, MBPI, MLI);
if (ViewMachineBlockFreqPropagationDAG != GVDT_None &&
(ViewBlockFreqFuncName.empty() ||
F.getName().equals(ViewBlockFreqFuncName))) {
view("MachineBlockFrequencyDAGS." + F.getName());
}
if (PrintMachineBlockFreq &&
(PrintBlockFreqFuncName.empty() ||
F.getName().equals(PrintBlockFreqFuncName))) {
MBFI->print(dbgs());
}
}
bool MachineBlockFrequencyInfo::runOnMachineFunction(MachineFunction &F) {
MachineBranchProbabilityInfo &MBPI =
getAnalysis<MachineBranchProbabilityInfo>();
MachineLoopInfo &MLI = getAnalysis<MachineLoopInfo>();
calculate(F, MBPI, MLI);
return false;
}
void MachineBlockFrequencyInfo::releaseMemory() { MBFI.reset(); }
/// Pop up a ghostview window with the current block frequency propagation
/// rendered using dot.
void MachineBlockFrequencyInfo::view(const Twine &Name, bool isSimple) const {
// This code is only for debugging.
ViewGraph(const_cast<MachineBlockFrequencyInfo *>(this), Name, isSimple);
}
BlockFrequency
MachineBlockFrequencyInfo::getBlockFreq(const MachineBasicBlock *MBB) const {
return MBFI ? MBFI->getBlockFreq(MBB) : 0;
}
Optional<uint64_t> MachineBlockFrequencyInfo::getBlockProfileCount(
const MachineBasicBlock *MBB) const {
const Function &F = MBFI->getFunction()->getFunction();
return MBFI ? MBFI->getBlockProfileCount(F, MBB) : None;
}
Optional<uint64_t>
MachineBlockFrequencyInfo::getProfileCountFromFreq(uint64_t Freq) const {
const Function &F = MBFI->getFunction()->getFunction();
return MBFI ? MBFI->getProfileCountFromFreq(F, Freq) : None;
}
bool MachineBlockFrequencyInfo::isIrrLoopHeader(
const MachineBasicBlock *MBB) const {
assert(MBFI && "Expected analysis to be available");
return MBFI->isIrrLoopHeader(MBB);
}
void MachineBlockFrequencyInfo::onEdgeSplit(
const MachineBasicBlock &NewPredecessor,
const MachineBasicBlock &NewSuccessor,
const MachineBranchProbabilityInfo &MBPI) {
assert(MBFI && "Expected analysis to be available");
auto NewSuccFreq = MBFI->getBlockFreq(&NewPredecessor) *
MBPI.getEdgeProbability(&NewPredecessor, &NewSuccessor);
MBFI->setBlockFreq(&NewSuccessor, NewSuccFreq.getFrequency());
}
const MachineFunction *MachineBlockFrequencyInfo::getFunction() const {
return MBFI ? MBFI->getFunction() : nullptr;
}
const MachineBranchProbabilityInfo *MachineBlockFrequencyInfo::getMBPI() const {
return MBFI ? &MBFI->getBPI() : nullptr;
}
raw_ostream &
MachineBlockFrequencyInfo::printBlockFreq(raw_ostream &OS,
const BlockFrequency Freq) const {
return MBFI ? MBFI->printBlockFreq(OS, Freq) : OS;
}
raw_ostream &
MachineBlockFrequencyInfo::printBlockFreq(raw_ostream &OS,
const MachineBasicBlock *MBB) const {
return MBFI ? MBFI->printBlockFreq(OS, MBB) : OS;
}
uint64_t MachineBlockFrequencyInfo::getEntryFreq() const {
return MBFI ? MBFI->getEntryFreq() : 0;
}
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