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/Analysis/CFGPrinter.h"
26 #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;
39 struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
40 static std::string getGraphName(const Function *F) {
41 return "CFG for '" + F->getName() + "' function";
44 static std::string getNodeLabel(const BasicBlock *Node,
45 const Function *Graph) {
46 if (CFGOnly && !Node->getName().empty())
47 return Node->getName() + ":";
49 std::ostringstream Out;
51 WriteAsOperand(Out, Node, false, true);
55 if (Node->getName().empty()) {
56 WriteAsOperand(Out, Node, false, true);
61 std::string OutStr = Out.str();
62 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
64 // Process string output to make it nicer...
65 for (unsigned i = 0; i != OutStr.length(); ++i)
66 if (OutStr[i] == '\n') { // Left justify
68 OutStr.insert(OutStr.begin()+i+1, 'l');
69 } else if (OutStr[i] == ';') { // Delete comments!
70 unsigned Idx = OutStr.find('\n', i+1); // Find end of line
71 OutStr.erase(OutStr.begin()+i, OutStr.begin()+Idx);
78 static std::string getNodeAttributes(const BasicBlock *N) {
79 return "fontname=Courier";
82 static std::string getEdgeSourceLabel(const BasicBlock *Node,
83 succ_const_iterator I) {
84 // Label source of conditional branches with "T" or "F"
85 if (const BranchInst *BI = dyn_cast<BranchInst>(Node->getTerminator()))
86 if (BI->isConditional())
87 return (I == succ_begin(Node)) ? "T" : "F";
94 struct CFGPrinter : public FunctionPass {
95 virtual bool runOnFunction(Function &F) {
96 std::string Filename = "cfg." + F.getName() + ".dot";
97 std::cerr << "Writing '" << Filename << "'...";
98 std::ofstream File(Filename.c_str());
101 WriteGraph(File, (const Function*)&F);
103 std::cerr << " error opening file for writing!";
108 void print(std::ostream &OS) const {}
110 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
111 AU.setPreservesAll();
115 RegisterAnalysis<CFGPrinter> P1("print-cfg",
116 "Print CFG of function to 'dot' file");
118 struct CFGOnlyPrinter : public CFGPrinter {
119 virtual bool runOnFunction(Function &F) {
120 bool OldCFGOnly = CFGOnly;
122 CFGPrinter::runOnFunction(F);
123 CFGOnly = OldCFGOnly;
126 void print(std::ostream &OS) const {}
128 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
129 AU.setPreservesAll();
133 RegisterAnalysis<CFGOnlyPrinter>
135 "Print CFG of function to 'dot' file (with no function bodies)");
138 /// viewCFG - This function is meant for use from the debugger. You can just
139 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
140 /// program, displaying the CFG of the current function. This depends on there
141 /// being a 'dot' and 'gv' program in your path.
143 void Function::viewCFG() const {
144 std::string Filename = "/tmp/cfg." + getName() + ".dot";
145 std::cerr << "Writing '" << Filename << "'... ";
146 std::ofstream F(Filename.c_str());
149 std::cerr << " error opening file for writing!\n";
157 std::cerr << "Running 'dot' program... " << std::flush;
158 if (system(("dot -Tps " + Filename + " > /tmp/cfg.tempgraph.ps").c_str())) {
159 std::cerr << "Error running dot: 'dot' not in path?\n";
162 system("gv /tmp/cfg.tempgraph.ps");
164 system(("rm " + Filename + " /tmp/cfg.tempgraph.ps").c_str());
167 /// viewCFGOnly - This function is meant for use from the debugger. It works
168 /// just like viewCFG, but it does not include the contents of basic blocks
169 /// into the nodes, just the label. If you are only interested in the CFG t
170 /// his can make the graph smaller.
172 void Function::viewCFGOnly() const {
178 FunctionPass *llvm::createCFGPrinterPass () {
179 return new CFGPrinter();
182 FunctionPass *llvm::createCFGOnlyPrinterPass () {
183 return new CFGOnlyPrinter();