1 //===- CallPrinter.cpp - DOT printer for call graph -----------------------===//
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
7 //===----------------------------------------------------------------------===//
9 // This file defines '-dot-callgraph', which emit a callgraph.<fnname>.dot
10 // containing the call graph of a module.
12 // There is also a pass available to directly call dotty ('-view-callgraph').
14 //===----------------------------------------------------------------------===//
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"
29 // This option shows static (relative) call counts.
31 // Need to show real counts when profile data is available
32 static cl::opt<bool> ShowHeatColors("callgraph-heat-colors", cl::init(false),
34 cl::desc("Show heat colors in call-graph"));
37 ShowEdgeWeight("callgraph-show-weights", cl::init(false), cl::Hidden,
38 cl::desc("Show edges labeled with weights"));
41 CallMultiGraph("callgraph-multigraph", cl::init(false), cl::Hidden,
42 cl::desc("Show call-multigraph (do not remove parallel edges)"));
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."));
50 class CallGraphDOTInfo {
54 DenseMap<const Function *, uint64_t> Freq;
58 std::function<BlockFrequencyInfo *(Function &)> LookupBFI;
60 CallGraphDOTInfo(Module *M, CallGraph *CG,
61 function_ref<BlockFrequencyInfo *(Function &)> LookupBFI)
62 : M(M), CG(CG), LookupBFI(LookupBFI) {
65 for (auto F = M->getFunctionList().begin(); F != M->getFunctionList().end(); ++F) {
66 uint64_t localSumFreq = 0;
67 SmallSet<Function *, 16> Callers;
68 for (User *U : (*F).users())
70 Callers.insert(cast<Instruction>(U)->getFunction());
71 for (auto iter = Callers.begin() ; iter != Callers.end() ; ++iter)
72 localSumFreq += getNumOfCalls((**iter), *F);
73 if (localSumFreq >= MaxFreq)
74 MaxFreq = localSumFreq;
75 Freq[&*F] = localSumFreq;
78 removeParallelEdges();
81 Module *getModule() const { return M; }
83 CallGraph *getCallGraph() const { return CG; }
85 uint64_t getFreq(const Function *F) { return Freq[F]; }
87 uint64_t getMaxFreq() { return MaxFreq; }
90 void removeParallelEdges() {
91 for (auto &I : (*CG)) {
92 CallGraphNode *Node = I.second.get();
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);
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();
118 typedef std::pair<const Function *const, std::unique_ptr<CallGraphNode>>
120 static const CallGraphNode *CGGetValuePtr(const PairTy &P) {
121 return P.second.get();
124 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
125 typedef mapped_iterator<CallGraph::const_iterator, decltype(&CGGetValuePtr)>
128 static nodes_iterator nodes_begin(CallGraphDOTInfo *CGInfo) {
129 return nodes_iterator(CGInfo->getCallGraph()->begin(), &CGGetValuePtr);
131 static nodes_iterator nodes_end(CallGraphDOTInfo *CGInfo) {
132 return nodes_iterator(CGInfo->getCallGraph()->end(), &CGGetValuePtr);
137 struct DOTGraphTraits<CallGraphDOTInfo *> : public DefaultDOTGraphTraits {
139 DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
141 static std::string getGraphName(CallGraphDOTInfo *CGInfo) {
142 return "Call graph: " +
143 std::string(CGInfo->getModule()->getModuleIdentifier());
146 static bool isNodeHidden(const CallGraphNode *Node) {
147 if (CallMultiGraph || Node->getFunction())
152 std::string getNodeLabel(const CallGraphNode *Node,
153 CallGraphDOTInfo *CGInfo) {
154 if (Node == CGInfo->getCallGraph()->getExternalCallingNode())
155 return "external caller";
156 if (Node == CGInfo->getCallGraph()->getCallsExternalNode())
157 return "external callee";
159 if (Function *Func = Node->getFunction())
160 return std::string(Func->getName());
161 return "external node";
163 static const CallGraphNode *CGGetValuePtr(CallGraphNode::CallRecord P) {
167 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
168 typedef mapped_iterator<CallGraphNode::const_iterator,
169 decltype(&CGGetValuePtr)>
172 std::string getEdgeAttributes(const CallGraphNode *Node, nodes_iterator I,
173 CallGraphDOTInfo *CGInfo) {
177 Function *Caller = Node->getFunction();
178 if (Caller == nullptr || Caller->isDeclaration())
181 Function *Callee = (*I)->getFunction();
182 if (Callee == nullptr)
185 uint64_t Counter = getNumOfCalls(*Caller, *Callee);
187 1 + 2 * (double(Counter) / CGInfo->getMaxFreq());
188 std::string Attrs = "label=\"" + std::to_string(Counter) +
189 "\" penwidth=" + std::to_string(Width);
193 std::string getNodeAttributes(const CallGraphNode *Node,
194 CallGraphDOTInfo *CGInfo) {
195 Function *F = Node->getFunction();
198 std::string attrs = "";
199 if (ShowHeatColors) {
200 uint64_t freq = CGInfo->getFreq(F);
201 std::string color = getHeatColor(freq, CGInfo->getMaxFreq());
202 std::string edgeColor = (freq <= (CGInfo->getMaxFreq() / 2))
205 attrs = "color=\"" + edgeColor + "ff\", style=filled, fillcolor=\"" +
212 } // end llvm namespace
216 class CallGraphViewer : public ModulePass {
219 CallGraphViewer() : ModulePass(ID) {}
221 void getAnalysisUsage(AnalysisUsage &AU) const override;
222 bool runOnModule(Module &M) override;
225 void CallGraphViewer::getAnalysisUsage(AnalysisUsage &AU) const {
226 ModulePass::getAnalysisUsage(AU);
227 AU.addRequired<BlockFrequencyInfoWrapperPass>();
228 AU.setPreservesAll();
231 bool CallGraphViewer::runOnModule(Module &M) {
232 auto LookupBFI = [this](Function &F) {
233 return &this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI();
237 CallGraphDOTInfo CFGInfo(&M, &CG, LookupBFI);
240 DOTGraphTraits<CallGraphDOTInfo *>::getGraphName(&CFGInfo);
241 ViewGraph(&CFGInfo, "callgraph", true, Title);
248 class CallGraphDOTPrinter : public ModulePass {
251 CallGraphDOTPrinter() : ModulePass(ID) {}
253 void getAnalysisUsage(AnalysisUsage &AU) const override;
254 bool runOnModule(Module &M) override;
257 void CallGraphDOTPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
258 ModulePass::getAnalysisUsage(AU);
259 AU.addRequired<BlockFrequencyInfoWrapperPass>();
260 AU.setPreservesAll();
263 bool CallGraphDOTPrinter::runOnModule(Module &M) {
264 auto LookupBFI = [this](Function &F) {
265 return &this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI();
268 std::string Filename;
269 if (!CallGraphDotFilenamePrefix.empty())
270 Filename = (CallGraphDotFilenamePrefix + ".callgraph.dot");
272 Filename = (std::string(M.getModuleIdentifier()) + ".callgraph.dot");
273 errs() << "Writing '" << Filename << "'...";
276 raw_fd_ostream File(Filename, EC, sys::fs::F_Text);
279 CallGraphDOTInfo CFGInfo(&M, &CG, LookupBFI);
282 WriteGraph(File, &CFGInfo);
284 errs() << " error opening file for writing!";
290 } // end anonymous namespace
292 char CallGraphViewer::ID = 0;
293 INITIALIZE_PASS(CallGraphViewer, "view-callgraph", "View call graph", false,
296 char CallGraphDOTPrinter::ID = 0;
297 INITIALIZE_PASS(CallGraphDOTPrinter, "dot-callgraph",
298 "Print call graph to 'dot' file", false, false)
300 // Create methods available outside of this file, to use them
301 // "include/llvm/LinkAllPasses.h". Otherwise the pass would be deleted by
302 // the link time optimization.
304 ModulePass *llvm::createCallGraphViewerPass() { return new CallGraphViewer(); }
306 ModulePass *llvm::createCallGraphDOTPrinterPass() {
307 return new CallGraphDOTPrinter();