1 //===- CallPrinter.cpp - DOT printer for call graph -----------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file defines '-dot-callgraph', which emit a callgraph.<fnname>.dot 10 // containing the call graph of a module. 11 // 12 // There is also a pass available to directly call dotty ('-view-callgraph'). 13 // 14 //===----------------------------------------------------------------------===// 15 16 #include "llvm/Analysis/CallPrinter.h" 17 #include "llvm/Analysis/BlockFrequencyInfo.h" 18 #include "llvm/Analysis/BranchProbabilityInfo.h" 19 #include "llvm/Analysis/CallGraph.h" 20 #include "llvm/Analysis/DOTGraphTraitsPass.h" 21 #include "llvm/Analysis/HeatUtils.h" 22 #include "llvm/Support/CommandLine.h" 23 #include "llvm/InitializePasses.h" 24 #include "llvm/ADT/DenseMap.h" 25 #include "llvm/ADT/SmallSet.h" 26 27 using namespace llvm; 28 29 // This option shows static (relative) call counts. 30 // FIXME: 31 // Need to show real counts when profile data is available 32 static cl::opt<bool> ShowHeatColors("callgraph-heat-colors", cl::init(false), 33 cl::Hidden, 34 cl::desc("Show heat colors in call-graph")); 35 36 static cl::opt<bool> 37 ShowEdgeWeight("callgraph-show-weights", cl::init(false), cl::Hidden, 38 cl::desc("Show edges labeled with weights")); 39 40 static cl::opt<bool> 41 CallMultiGraph("callgraph-multigraph", cl::init(false), cl::Hidden, 42 cl::desc("Show call-multigraph (do not remove parallel edges)")); 43 44 static cl::opt<std::string> CallGraphDotFilenamePrefix( 45 "callgraph-dot-filename-prefix", cl::Hidden, 46 cl::desc("The prefix used for the CallGraph dot file names.")); 47 48 namespace llvm { 49 50 class CallGraphDOTInfo { 51 private: 52 Module *M; 53 CallGraph *CG; 54 DenseMap<const Function *, uint64_t> Freq; 55 uint64_t MaxFreq; 56 57 public: 58 std::function<BlockFrequencyInfo *(Function &)> LookupBFI; 59 60 CallGraphDOTInfo(Module *M, CallGraph *CG, 61 function_ref<BlockFrequencyInfo *(Function &)> LookupBFI) 62 : M(M), CG(CG), LookupBFI(LookupBFI) { 63 MaxFreq = 0; 64 65 for (Function &F : M->getFunctionList()) { 66 uint64_t localSumFreq = 0; 67 SmallSet<Function *, 16> Callers; 68 for (User *U : F.users()) 69 if (isa<CallInst>(U)) 70 Callers.insert(cast<Instruction>(U)->getFunction()); 71 for (Function *Caller : Callers) 72 localSumFreq += getNumOfCalls(*Caller, F); 73 if (localSumFreq >= MaxFreq) 74 MaxFreq = localSumFreq; 75 Freq[&F] = localSumFreq; 76 } 77 if (!CallMultiGraph) 78 removeParallelEdges(); 79 } 80 81 Module *getModule() const { return M; } 82 83 CallGraph *getCallGraph() const { return CG; } 84 85 uint64_t getFreq(const Function *F) { return Freq[F]; } 86 87 uint64_t getMaxFreq() { return MaxFreq; } 88 89 private: 90 void removeParallelEdges() { 91 for (auto &I : (*CG)) { 92 CallGraphNode *Node = I.second.get(); 93 94 bool FoundParallelEdge = true; 95 while (FoundParallelEdge) { 96 SmallSet<Function *, 16> Visited; 97 FoundParallelEdge = false; 98 for (auto CI = Node->begin(), CE = Node->end(); CI != CE; CI++) { 99 if (!(Visited.insert(CI->second->getFunction())).second) { 100 FoundParallelEdge = true; 101 Node->removeCallEdge(CI); 102 break; 103 } 104 } 105 } 106 } 107 } 108 }; 109 110 template <> 111 struct GraphTraits<CallGraphDOTInfo *> 112 : public GraphTraits<const CallGraphNode *> { 113 static NodeRef getEntryNode(CallGraphDOTInfo *CGInfo) { 114 // Start at the external node! 115 return CGInfo->getCallGraph()->getExternalCallingNode(); 116 } 117 118 typedef std::pair<const Function *const, std::unique_ptr<CallGraphNode>> 119 PairTy; 120 static const CallGraphNode *CGGetValuePtr(const PairTy &P) { 121 return P.second.get(); 122 } 123 124 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 125 typedef mapped_iterator<CallGraph::const_iterator, decltype(&CGGetValuePtr)> 126 nodes_iterator; 127 128 static nodes_iterator nodes_begin(CallGraphDOTInfo *CGInfo) { 129 return nodes_iterator(CGInfo->getCallGraph()->begin(), &CGGetValuePtr); 130 } 131 static nodes_iterator nodes_end(CallGraphDOTInfo *CGInfo) { 132 return nodes_iterator(CGInfo->getCallGraph()->end(), &CGGetValuePtr); 133 } 134 }; 135 136 template <> 137 struct DOTGraphTraits<CallGraphDOTInfo *> : public DefaultDOTGraphTraits { 138 139 DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {} 140 141 static std::string getGraphName(CallGraphDOTInfo *CGInfo) { 142 return "Call graph: " + 143 std::string(CGInfo->getModule()->getModuleIdentifier()); 144 } 145 146 static bool isNodeHidden(const CallGraphNode *Node, 147 const CallGraphDOTInfo *CGInfo) { 148 if (CallMultiGraph || Node->getFunction()) 149 return false; 150 return true; 151 } 152 153 std::string getNodeLabel(const CallGraphNode *Node, 154 CallGraphDOTInfo *CGInfo) { 155 if (Node == CGInfo->getCallGraph()->getExternalCallingNode()) 156 return "external caller"; 157 if (Node == CGInfo->getCallGraph()->getCallsExternalNode()) 158 return "external callee"; 159 160 if (Function *Func = Node->getFunction()) 161 return std::string(Func->getName()); 162 return "external node"; 163 } 164 static const CallGraphNode *CGGetValuePtr(CallGraphNode::CallRecord P) { 165 return P.second; 166 } 167 168 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 169 typedef mapped_iterator<CallGraphNode::const_iterator, 170 decltype(&CGGetValuePtr)> 171 nodes_iterator; 172 173 std::string getEdgeAttributes(const CallGraphNode *Node, nodes_iterator I, 174 CallGraphDOTInfo *CGInfo) { 175 if (!ShowEdgeWeight) 176 return ""; 177 178 Function *Caller = Node->getFunction(); 179 if (Caller == nullptr || Caller->isDeclaration()) 180 return ""; 181 182 Function *Callee = (*I)->getFunction(); 183 if (Callee == nullptr) 184 return ""; 185 186 uint64_t Counter = getNumOfCalls(*Caller, *Callee); 187 double Width = 188 1 + 2 * (double(Counter) / CGInfo->getMaxFreq()); 189 std::string Attrs = "label=\"" + std::to_string(Counter) + 190 "\" penwidth=" + std::to_string(Width); 191 return Attrs; 192 } 193 194 std::string getNodeAttributes(const CallGraphNode *Node, 195 CallGraphDOTInfo *CGInfo) { 196 Function *F = Node->getFunction(); 197 if (F == nullptr) 198 return ""; 199 std::string attrs; 200 if (ShowHeatColors) { 201 uint64_t freq = CGInfo->getFreq(F); 202 std::string color = getHeatColor(freq, CGInfo->getMaxFreq()); 203 std::string edgeColor = (freq <= (CGInfo->getMaxFreq() / 2)) 204 ? getHeatColor(0) 205 : getHeatColor(1); 206 attrs = "color=\"" + edgeColor + "ff\", style=filled, fillcolor=\"" + 207 color + "80\""; 208 } 209 return attrs; 210 } 211 }; 212 213 } // end llvm namespace 214 215 namespace { 216 // Viewer 217 class CallGraphViewer : public ModulePass { 218 public: 219 static char ID; 220 CallGraphViewer() : ModulePass(ID) {} 221 222 void getAnalysisUsage(AnalysisUsage &AU) const override; 223 bool runOnModule(Module &M) override; 224 }; 225 226 void CallGraphViewer::getAnalysisUsage(AnalysisUsage &AU) const { 227 ModulePass::getAnalysisUsage(AU); 228 AU.addRequired<BlockFrequencyInfoWrapperPass>(); 229 AU.setPreservesAll(); 230 } 231 232 bool CallGraphViewer::runOnModule(Module &M) { 233 auto LookupBFI = [this](Function &F) { 234 return &this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI(); 235 }; 236 237 CallGraph CG(M); 238 CallGraphDOTInfo CFGInfo(&M, &CG, LookupBFI); 239 240 std::string Title = 241 DOTGraphTraits<CallGraphDOTInfo *>::getGraphName(&CFGInfo); 242 ViewGraph(&CFGInfo, "callgraph", true, Title); 243 244 return false; 245 } 246 247 // DOT Printer 248 249 class CallGraphDOTPrinter : public ModulePass { 250 public: 251 static char ID; 252 CallGraphDOTPrinter() : ModulePass(ID) {} 253 254 void getAnalysisUsage(AnalysisUsage &AU) const override; 255 bool runOnModule(Module &M) override; 256 }; 257 258 void CallGraphDOTPrinter::getAnalysisUsage(AnalysisUsage &AU) const { 259 ModulePass::getAnalysisUsage(AU); 260 AU.addRequired<BlockFrequencyInfoWrapperPass>(); 261 AU.setPreservesAll(); 262 } 263 264 bool CallGraphDOTPrinter::runOnModule(Module &M) { 265 auto LookupBFI = [this](Function &F) { 266 return &this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI(); 267 }; 268 269 std::string Filename; 270 if (!CallGraphDotFilenamePrefix.empty()) 271 Filename = (CallGraphDotFilenamePrefix + ".callgraph.dot"); 272 else 273 Filename = (std::string(M.getModuleIdentifier()) + ".callgraph.dot"); 274 errs() << "Writing '" << Filename << "'..."; 275 276 std::error_code EC; 277 raw_fd_ostream File(Filename, EC, sys::fs::OF_Text); 278 279 CallGraph CG(M); 280 CallGraphDOTInfo CFGInfo(&M, &CG, LookupBFI); 281 282 if (!EC) 283 WriteGraph(File, &CFGInfo); 284 else 285 errs() << " error opening file for writing!"; 286 errs() << "\n"; 287 288 return false; 289 } 290 291 } // end anonymous namespace 292 293 char CallGraphViewer::ID = 0; 294 INITIALIZE_PASS(CallGraphViewer, "view-callgraph", "View call graph", false, 295 false) 296 297 char CallGraphDOTPrinter::ID = 0; 298 INITIALIZE_PASS(CallGraphDOTPrinter, "dot-callgraph", 299 "Print call graph to 'dot' file", false, false) 300 301 // Create methods available outside of this file, to use them 302 // "include/llvm/LinkAllPasses.h". Otherwise the pass would be deleted by 303 // the link time optimization. 304 305 ModulePass *llvm::createCallGraphViewerPass() { return new CallGraphViewer(); } 306 307 ModulePass *llvm::createCallGraphDOTPrinterPass() { 308 return new CallGraphDOTPrinter(); 309 } 310