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"
29 /// CFGOnly flag - This is used to control whether or not the CFG graph printer
30 /// prints out the contents of basic blocks or not. This is acceptable because
31 /// this code is only really used for debugging purposes.
33 static bool CFGOnly = false;
36 struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
37 static std::string getGraphName(const Function *F) {
38 return "CFG for '" + F->getName() + "' function";
41 static std::string getNodeLabel(const BasicBlock *Node,
42 const Function *Graph) {
43 if (CFGOnly && !Node->getName().empty())
44 return Node->getName() + ":";
46 std::ostringstream Out;
48 WriteAsOperand(Out, Node, false, true);
52 if (Node->getName().empty()) {
53 WriteAsOperand(Out, Node, false, true);
58 std::string OutStr = Out.str();
59 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
61 // Process string output to make it nicer...
62 for (unsigned i = 0; i != OutStr.length(); ++i)
63 if (OutStr[i] == '\n') { // Left justify
65 OutStr.insert(OutStr.begin()+i+1, 'l');
66 } else if (OutStr[i] == ';') { // Delete comments!
67 unsigned Idx = OutStr.find('\n', i+1); // Find end of line
68 OutStr.erase(OutStr.begin()+i, OutStr.begin()+Idx);
75 static std::string getNodeAttributes(const BasicBlock *N) {
76 return "fontname=Courier";
79 static std::string getEdgeSourceLabel(const BasicBlock *Node,
80 succ_const_iterator I) {
81 // Label source of conditional branches with "T" or "F"
82 if (const BranchInst *BI = dyn_cast<BranchInst>(Node->getTerminator()))
83 if (BI->isConditional())
84 return (I == succ_begin(Node)) ? "T" : "F";
90 struct CFGPrinter : public FunctionPass {
91 virtual bool runOnFunction(Function &F) {
92 std::string Filename = "cfg." + F.getName() + ".dot";
93 std::cerr << "Writing '" << Filename << "'...";
94 std::ofstream File(Filename.c_str());
97 WriteGraph(File, (const Function*)&F);
99 std::cerr << " error opening file for writing!";
104 void print(std::ostream &OS) const {}
106 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
107 AU.setPreservesAll();
111 RegisterAnalysis<CFGPrinter> P1("print-cfg",
112 "Print CFG of function to 'dot' file");
118 /// viewCFG - This function is meant for use from the debugger. You can just
119 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
120 /// program, displaying the CFG of the current function. This depends on there
121 /// being a 'dot' and 'gv' program in your path.
123 void Function::viewCFG() const {
124 std::string Filename = "/tmp/cfg." + getName() + ".dot";
125 std::cerr << "Writing '" << Filename << "'... ";
126 std::ofstream F(Filename.c_str());
129 std::cerr << " error opening file for writing!\n";
137 std::cerr << "Running 'dot' program... " << std::flush;
138 if (system(("dot -Tps " + Filename + " > /tmp/cfg.tempgraph.ps").c_str())) {
139 std::cerr << "Error running dot: 'dot' not in path?\n";
142 system("gv /tmp/cfg.tempgraph.ps");
144 system(("rm " + Filename + " /tmp/cfg.tempgraph.ps").c_str());
147 /// viewCFGOnly - This function is meant for use from the debugger. It works
148 /// just like viewCFG, but it does not include the contents of basic blocks
149 /// into the nodes, just the label. If you are only interested in the CFG t
150 /// his can make the graph smaller.
152 void Function::viewCFGOnly() const {