1 //===- MachineBlockFrequencyInfo.cpp - MBB Frequency Analysis -------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // Loops should be simplified before this analysis. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h" 15 #include "llvm/ADT/DenseMap.h" 16 #include "llvm/ADT/None.h" 17 #include "llvm/ADT/iterator.h" 18 #include "llvm/Analysis/BlockFrequencyInfoImpl.h" 19 #include "llvm/CodeGen/MachineBasicBlock.h" 20 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h" 21 #include "llvm/CodeGen/MachineFunction.h" 22 #include "llvm/CodeGen/MachineLoopInfo.h" 23 #include "llvm/Pass.h" 24 #include "llvm/Support/CommandLine.h" 25 #include "llvm/Support/GraphWriter.h" 26 #include <string> 27 28 using namespace llvm; 29 30 #define DEBUG_TYPE "machine-block-freq" 31 32 static cl::opt<GVDAGType> ViewMachineBlockFreqPropagationDAG( 33 "view-machine-block-freq-propagation-dags", cl::Hidden, 34 cl::desc("Pop up a window to show a dag displaying how machine block " 35 "frequencies propagate through the CFG."), 36 cl::values(clEnumValN(GVDT_None, "none", "do not display graphs."), 37 clEnumValN(GVDT_Fraction, "fraction", 38 "display a graph using the " 39 "fractional block frequency representation."), 40 clEnumValN(GVDT_Integer, "integer", 41 "display a graph using the raw " 42 "integer fractional block frequency representation."), 43 clEnumValN(GVDT_Count, "count", "display a graph using the real " 44 "profile count if available."))); 45 46 // Similar option above, but used to control BFI display only after MBP pass 47 cl::opt<GVDAGType> ViewBlockLayoutWithBFI( 48 "view-block-layout-with-bfi", cl::Hidden, 49 cl::desc( 50 "Pop up a window to show a dag displaying MBP layout and associated " 51 "block frequencies of the CFG."), 52 cl::values(clEnumValN(GVDT_None, "none", "do not display graphs."), 53 clEnumValN(GVDT_Fraction, "fraction", 54 "display a graph using the " 55 "fractional block frequency representation."), 56 clEnumValN(GVDT_Integer, "integer", 57 "display a graph using the raw " 58 "integer fractional block frequency representation."), 59 clEnumValN(GVDT_Count, "count", 60 "display a graph using the real " 61 "profile count if available."))); 62 63 // Command line option to specify the name of the function for CFG dump 64 // Defined in Analysis/BlockFrequencyInfo.cpp: -view-bfi-func-name= 65 extern cl::opt<std::string> ViewBlockFreqFuncName; 66 67 // Command line option to specify hot frequency threshold. 68 // Defined in Analysis/BlockFrequencyInfo.cpp: -view-hot-freq-perc= 69 extern cl::opt<unsigned> ViewHotFreqPercent; 70 71 static cl::opt<bool> PrintMachineBlockFreq( 72 "print-machine-bfi", cl::init(false), cl::Hidden, 73 cl::desc("Print the machine block frequency info.")); 74 75 // Command line option to specify the name of the function for block frequency 76 // dump. Defined in Analysis/BlockFrequencyInfo.cpp. 77 extern cl::opt<std::string> PrintBlockFreqFuncName; 78 79 static GVDAGType getGVDT() { 80 if (ViewBlockLayoutWithBFI != GVDT_None) 81 return ViewBlockLayoutWithBFI; 82 83 return ViewMachineBlockFreqPropagationDAG; 84 } 85 86 namespace llvm { 87 88 template <> struct GraphTraits<MachineBlockFrequencyInfo *> { 89 using NodeRef = const MachineBasicBlock *; 90 using ChildIteratorType = MachineBasicBlock::const_succ_iterator; 91 using nodes_iterator = pointer_iterator<MachineFunction::const_iterator>; 92 93 static NodeRef getEntryNode(const MachineBlockFrequencyInfo *G) { 94 return &G->getFunction()->front(); 95 } 96 97 static ChildIteratorType child_begin(const NodeRef N) { 98 return N->succ_begin(); 99 } 100 101 static ChildIteratorType child_end(const NodeRef N) { return N->succ_end(); } 102 103 static nodes_iterator nodes_begin(const MachineBlockFrequencyInfo *G) { 104 return nodes_iterator(G->getFunction()->begin()); 105 } 106 107 static nodes_iterator nodes_end(const MachineBlockFrequencyInfo *G) { 108 return nodes_iterator(G->getFunction()->end()); 109 } 110 }; 111 112 using MBFIDOTGraphTraitsBase = 113 BFIDOTGraphTraitsBase<MachineBlockFrequencyInfo, 114 MachineBranchProbabilityInfo>; 115 116 template <> 117 struct DOTGraphTraits<MachineBlockFrequencyInfo *> 118 : public MBFIDOTGraphTraitsBase { 119 const MachineFunction *CurFunc = nullptr; 120 DenseMap<const MachineBasicBlock *, int> LayoutOrderMap; 121 122 explicit DOTGraphTraits(bool isSimple = false) 123 : MBFIDOTGraphTraitsBase(isSimple) {} 124 125 std::string getNodeLabel(const MachineBasicBlock *Node, 126 const MachineBlockFrequencyInfo *Graph) { 127 int layout_order = -1; 128 // Attach additional ordering information if 'isSimple' is false. 129 if (!isSimple()) { 130 const MachineFunction *F = Node->getParent(); 131 if (!CurFunc || F != CurFunc) { 132 if (CurFunc) 133 LayoutOrderMap.clear(); 134 135 CurFunc = F; 136 int O = 0; 137 for (auto MBI = F->begin(); MBI != F->end(); ++MBI, ++O) { 138 LayoutOrderMap[&*MBI] = O; 139 } 140 } 141 layout_order = LayoutOrderMap[Node]; 142 } 143 return MBFIDOTGraphTraitsBase::getNodeLabel(Node, Graph, getGVDT(), 144 layout_order); 145 } 146 147 std::string getNodeAttributes(const MachineBasicBlock *Node, 148 const MachineBlockFrequencyInfo *Graph) { 149 return MBFIDOTGraphTraitsBase::getNodeAttributes(Node, Graph, 150 ViewHotFreqPercent); 151 } 152 153 std::string getEdgeAttributes(const MachineBasicBlock *Node, EdgeIter EI, 154 const MachineBlockFrequencyInfo *MBFI) { 155 return MBFIDOTGraphTraitsBase::getEdgeAttributes( 156 Node, EI, MBFI, MBFI->getMBPI(), ViewHotFreqPercent); 157 } 158 }; 159 160 } // end namespace llvm 161 162 INITIALIZE_PASS_BEGIN(MachineBlockFrequencyInfo, DEBUG_TYPE, 163 "Machine Block Frequency Analysis", true, true) 164 INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo) 165 INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo) 166 INITIALIZE_PASS_END(MachineBlockFrequencyInfo, DEBUG_TYPE, 167 "Machine Block Frequency Analysis", true, true) 168 169 char MachineBlockFrequencyInfo::ID = 0; 170 171 MachineBlockFrequencyInfo::MachineBlockFrequencyInfo() 172 : MachineFunctionPass(ID) { 173 initializeMachineBlockFrequencyInfoPass(*PassRegistry::getPassRegistry()); 174 } 175 176 MachineBlockFrequencyInfo::~MachineBlockFrequencyInfo() = default; 177 178 void MachineBlockFrequencyInfo::getAnalysisUsage(AnalysisUsage &AU) const { 179 AU.addRequired<MachineBranchProbabilityInfo>(); 180 AU.addRequired<MachineLoopInfo>(); 181 AU.setPreservesAll(); 182 MachineFunctionPass::getAnalysisUsage(AU); 183 } 184 185 void MachineBlockFrequencyInfo::calculate( 186 const MachineFunction &F, const MachineBranchProbabilityInfo &MBPI, 187 const MachineLoopInfo &MLI) { 188 if (!MBFI) 189 MBFI.reset(new ImplType); 190 MBFI->calculate(F, MBPI, MLI); 191 if (ViewMachineBlockFreqPropagationDAG != GVDT_None && 192 (ViewBlockFreqFuncName.empty() || 193 F.getName().equals(ViewBlockFreqFuncName))) { 194 view("MachineBlockFrequencyDAGS." + F.getName()); 195 } 196 if (PrintMachineBlockFreq && 197 (PrintBlockFreqFuncName.empty() || 198 F.getName().equals(PrintBlockFreqFuncName))) { 199 MBFI->print(dbgs()); 200 } 201 } 202 203 bool MachineBlockFrequencyInfo::runOnMachineFunction(MachineFunction &F) { 204 MachineBranchProbabilityInfo &MBPI = 205 getAnalysis<MachineBranchProbabilityInfo>(); 206 MachineLoopInfo &MLI = getAnalysis<MachineLoopInfo>(); 207 calculate(F, MBPI, MLI); 208 return false; 209 } 210 211 void MachineBlockFrequencyInfo::releaseMemory() { MBFI.reset(); } 212 213 /// Pop up a ghostview window with the current block frequency propagation 214 /// rendered using dot. 215 void MachineBlockFrequencyInfo::view(const Twine &Name, bool isSimple) const { 216 // This code is only for debugging. 217 ViewGraph(const_cast<MachineBlockFrequencyInfo *>(this), Name, isSimple); 218 } 219 220 BlockFrequency 221 MachineBlockFrequencyInfo::getBlockFreq(const MachineBasicBlock *MBB) const { 222 return MBFI ? MBFI->getBlockFreq(MBB) : 0; 223 } 224 225 Optional<uint64_t> MachineBlockFrequencyInfo::getBlockProfileCount( 226 const MachineBasicBlock *MBB) const { 227 const Function &F = MBFI->getFunction()->getFunction(); 228 return MBFI ? MBFI->getBlockProfileCount(F, MBB) : None; 229 } 230 231 Optional<uint64_t> 232 MachineBlockFrequencyInfo::getProfileCountFromFreq(uint64_t Freq) const { 233 const Function &F = MBFI->getFunction()->getFunction(); 234 return MBFI ? MBFI->getProfileCountFromFreq(F, Freq) : None; 235 } 236 237 bool 238 MachineBlockFrequencyInfo::isIrrLoopHeader(const MachineBasicBlock *MBB) { 239 assert(MBFI && "Expected analysis to be available"); 240 return MBFI->isIrrLoopHeader(MBB); 241 } 242 243 const MachineFunction *MachineBlockFrequencyInfo::getFunction() const { 244 return MBFI ? MBFI->getFunction() : nullptr; 245 } 246 247 const MachineBranchProbabilityInfo *MachineBlockFrequencyInfo::getMBPI() const { 248 return MBFI ? &MBFI->getBPI() : nullptr; 249 } 250 251 raw_ostream & 252 MachineBlockFrequencyInfo::printBlockFreq(raw_ostream &OS, 253 const BlockFrequency Freq) const { 254 return MBFI ? MBFI->printBlockFreq(OS, Freq) : OS; 255 } 256 257 raw_ostream & 258 MachineBlockFrequencyInfo::printBlockFreq(raw_ostream &OS, 259 const MachineBasicBlock *MBB) const { 260 return MBFI ? MBFI->printBlockFreq(OS, MBB) : OS; 261 } 262 263 uint64_t MachineBlockFrequencyInfo::getEntryFreq() const { 264 return MBFI ? MBFI->getEntryFreq() : 0; 265 } 266