| //===- 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" |
| |
| namespace llvm { |
| 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; |
| } // namespace llvm |
| |
| 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 { |
| if (!MBFI) |
| return None; |
| |
| const Function &F = MBFI->getFunction()->getFunction(); |
| return MBFI->getBlockProfileCount(F, MBB); |
| } |
| |
| Optional<uint64_t> |
| MachineBlockFrequencyInfo::getProfileCountFromFreq(uint64_t Freq) const { |
| if (!MBFI) |
| return None; |
| |
| const Function &F = MBFI->getFunction()->getFunction(); |
| return MBFI->getProfileCountFromFreq(F, Freq); |
| } |
| |
| 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; |
| } |