1 //===- CFGPrinter.cpp - DOT printer for the control flow graph ------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines a '-print-cfg' analysis pass, which emits the
11 // cfg.<fnname>.dot file for each function in the program, with a graph of the
12 // CFG for that function.
14 // The other main feature of this file is that it implements the
15 // Function::viewCFG method, which is useful for debugging passes which operate
18 //===----------------------------------------------------------------------===//
20 #include "Support/GraphWriter.h"
21 #include "llvm/Pass.h"
22 #include "llvm/Function.h"
23 #include "llvm/iTerminators.h"
24 #include "llvm/Assembly/Writer.h"
25 #include "llvm/Support/CFG.h"
31 /// CFGOnly flag - This is used to control whether or not the CFG graph printer
32 /// prints out the contents of basic blocks or not. This is acceptable because
33 /// this code is only really used for debugging purposes.
35 static bool CFGOnly = false;
38 struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
39 static std::string getGraphName(const Function *F) {
40 return "CFG for '" + F->getName() + "' function";
43 static std::string getNodeLabel(const BasicBlock *Node,
44 const Function *Graph) {
45 if (CFGOnly && !Node->getName().empty())
46 return Node->getName() + ":";
48 std::ostringstream Out;
50 WriteAsOperand(Out, Node, false, true);
54 if (Node->getName().empty()) {
55 WriteAsOperand(Out, Node, false, true);
60 std::string OutStr = Out.str();
61 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
63 // Process string output to make it nicer...
64 for (unsigned i = 0; i != OutStr.length(); ++i)
65 if (OutStr[i] == '\n') { // Left justify
67 OutStr.insert(OutStr.begin()+i+1, 'l');
68 } else if (OutStr[i] == ';') { // Delete comments!
69 unsigned Idx = OutStr.find('\n', i+1); // Find end of line
70 OutStr.erase(OutStr.begin()+i, OutStr.begin()+Idx);
77 static std::string getNodeAttributes(const BasicBlock *N) {
78 return "fontname=Courier";
81 static std::string getEdgeSourceLabel(const BasicBlock *Node,
82 succ_const_iterator I) {
83 // Label source of conditional branches with "T" or "F"
84 if (const BranchInst *BI = dyn_cast<BranchInst>(Node->getTerminator()))
85 if (BI->isConditional())
86 return (I == succ_begin(Node)) ? "T" : "F";
92 struct CFGPrinter : public FunctionPass {
93 virtual bool runOnFunction(Function &F) {
94 std::string Filename = "cfg." + F.getName() + ".dot";
95 std::cerr << "Writing '" << Filename << "'...";
96 std::ofstream File(Filename.c_str());
99 WriteGraph(File, (const Function*)&F);
101 std::cerr << " error opening file for writing!";
106 void print(std::ostream &OS) const {}
108 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
109 AU.setPreservesAll();
113 RegisterAnalysis<CFGPrinter> P1("print-cfg",
114 "Print CFG of function to 'dot' file");
117 /// viewCFG - This function is meant for use from the debugger. You can just
118 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
119 /// program, displaying the CFG of the current function. This depends on there
120 /// being a 'dot' and 'gv' program in your path.
122 void Function::viewCFG() const {
123 std::string Filename = "/tmp/cfg." + getName() + ".dot";
124 std::cerr << "Writing '" << Filename << "'... ";
125 std::ofstream F(Filename.c_str());
128 std::cerr << " error opening file for writing!\n";
136 std::cerr << "Running 'dot' program... " << std::flush;
137 if (system(("dot -Tps " + Filename + " > /tmp/cfg.tempgraph.ps").c_str())) {
138 std::cerr << "Error running dot: 'dot' not in path?\n";
141 system("gv /tmp/cfg.tempgraph.ps");
143 system(("rm " + Filename + " /tmp/cfg.tempgraph.ps").c_str());
146 /// viewCFGOnly - This function is meant for use from the debugger. It works
147 /// just like viewCFG, but it does not include the contents of basic blocks
148 /// into the nodes, just the label. If you are only interested in the CFG t
149 /// his can make the graph smaller.
151 void Function::viewCFGOnly() const {
157 } // End llvm namespace