1 //===- CFGPrinter.cpp - DOT printer for the control flow graph ------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines a '-dot-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.
13 //
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
16 // on the CFG.
17 //
18 //===----------------------------------------------------------------------===//
19 
20 #include "llvm/Function.h"
21 #include "llvm/Instructions.h"
22 #include "llvm/Pass.h"
23 #include "llvm/Analysis/CFGPrinter.h"
24 #include "llvm/Assembly/Writer.h"
25 #include "llvm/Support/CFG.h"
26 #include "llvm/Support/Compiler.h"
27 #include "llvm/Support/GraphWriter.h"
28 #include "llvm/Config/config.h"
29 #include <iosfwd>
30 #include <sstream>
31 #include <fstream>
32 using namespace llvm;
33 
34 namespace llvm {
35 template<>
36 struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
37   static std::string getGraphName(const Function *F) {
38     return "CFG for '" + F->getNameStr() + "' function";
39   }
40 
41   static std::string getNodeLabel(const BasicBlock *Node,
42                                   const Function *Graph,
43                                   bool ShortNames) {
44     if (ShortNames && !Node->getName().empty())
45       return Node->getNameStr() + ":";
46 
47     std::ostringstream Out;
48     if (ShortNames) {
49       WriteAsOperand(Out, Node, false);
50       return Out.str();
51     }
52 
53     if (Node->getName().empty()) {
54       WriteAsOperand(Out, Node, false);
55       Out << ":";
56     }
57 
58     Out << *Node;
59     std::string OutStr = Out.str();
60     if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
61 
62     // Process string output to make it nicer...
63     for (unsigned i = 0; i != OutStr.length(); ++i)
64       if (OutStr[i] == '\n') {                            // Left justify
65         OutStr[i] = '\\';
66         OutStr.insert(OutStr.begin()+i+1, 'l');
67       } else if (OutStr[i] == ';') {                      // Delete comments!
68         unsigned Idx = OutStr.find('\n', i+1);            // Find end of line
69         OutStr.erase(OutStr.begin()+i, OutStr.begin()+Idx);
70         --i;
71       }
72 
73     return OutStr;
74   }
75 
76   static std::string getEdgeSourceLabel(const BasicBlock *Node,
77                                         succ_const_iterator I) {
78     // Label source of conditional branches with "T" or "F"
79     if (const BranchInst *BI = dyn_cast<BranchInst>(Node->getTerminator()))
80       if (BI->isConditional())
81         return (I == succ_begin(Node)) ? "T" : "F";
82     return "";
83   }
84 };
85 }
86 
87 namespace {
88   struct VISIBILITY_HIDDEN CFGViewer : public FunctionPass {
89     static char ID; // Pass identifcation, replacement for typeid
90     CFGViewer() : FunctionPass(&ID) {}
91 
92     virtual bool runOnFunction(Function &F) {
93       F.viewCFG();
94       return false;
95     }
96 
97     void print(std::ostream &OS, const Module* = 0) const {}
98 
99     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
100       AU.setPreservesAll();
101     }
102   };
103 }
104 
105 char CFGViewer::ID = 0;
106 static RegisterPass<CFGViewer>
107 V0("view-cfg", "View CFG of function", false, true);
108 
109 namespace {
110   struct VISIBILITY_HIDDEN CFGOnlyViewer : public FunctionPass {
111     static char ID; // Pass identifcation, replacement for typeid
112     CFGOnlyViewer() : FunctionPass(&ID) {}
113 
114     virtual bool runOnFunction(Function &F) {
115       F.viewCFG();
116       return false;
117     }
118 
119     void print(std::ostream &OS, const Module* = 0) const {}
120 
121     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
122       AU.setPreservesAll();
123     }
124   };
125 }
126 
127 char CFGOnlyViewer::ID = 0;
128 static RegisterPass<CFGOnlyViewer>
129 V1("view-cfg-only",
130    "View CFG of function (with no function bodies)", false, true);
131 
132 namespace {
133   struct VISIBILITY_HIDDEN CFGPrinter : public FunctionPass {
134     static char ID; // Pass identification, replacement for typeid
135     CFGPrinter() : FunctionPass(&ID) {}
136     explicit CFGPrinter(void *pid) : FunctionPass(pid) {}
137 
138     virtual bool runOnFunction(Function &F) {
139       std::string Filename = "cfg." + F.getNameStr() + ".dot";
140       cerr << "Writing '" << Filename << "'...";
141       std::ofstream File(Filename.c_str());
142 
143       if (File.good())
144         WriteGraph(File, (const Function*)&F);
145       else
146         cerr << "  error opening file for writing!";
147       cerr << "\n";
148       return false;
149     }
150 
151     void print(std::ostream &OS, const Module* = 0) const {}
152 
153     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
154       AU.setPreservesAll();
155     }
156   };
157 }
158 
159 char CFGPrinter::ID = 0;
160 static RegisterPass<CFGPrinter>
161 P1("dot-cfg", "Print CFG of function to 'dot' file", false, true);
162 
163 namespace {
164   struct VISIBILITY_HIDDEN CFGOnlyPrinter : public FunctionPass {
165     static char ID; // Pass identification, replacement for typeid
166     CFGOnlyPrinter() : FunctionPass(&ID) {}
167     explicit CFGOnlyPrinter(void *pid) : FunctionPass(pid) {}
168     virtual bool runOnFunction(Function &F) {
169       std::string Filename = "cfg." + F.getNameStr() + ".dot";
170       cerr << "Writing '" << Filename << "'...";
171       std::ofstream File(Filename.c_str());
172 
173       if (File.good())
174         WriteGraph(File, (const Function*)&F, true);
175       else
176         cerr << "  error opening file for writing!";
177       cerr << "\n";
178       return false;
179     }
180     void print(std::ostream &OS, const Module* = 0) const {}
181 
182     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
183       AU.setPreservesAll();
184     }
185   };
186 }
187 
188 char CFGOnlyPrinter::ID = 0;
189 static RegisterPass<CFGOnlyPrinter>
190 P2("dot-cfg-only",
191    "Print CFG of function to 'dot' file (with no function bodies)", false, true);
192 
193 /// viewCFG - This function is meant for use from the debugger.  You can just
194 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
195 /// program, displaying the CFG of the current function.  This depends on there
196 /// being a 'dot' and 'gv' program in your path.
197 ///
198 void Function::viewCFG() const {
199   ViewGraph(this, "cfg" + getNameStr());
200 }
201 
202 /// viewCFGOnly - This function is meant for use from the debugger.  It works
203 /// just like viewCFG, but it does not include the contents of basic blocks
204 /// into the nodes, just the label.  If you are only interested in the CFG t
205 /// his can make the graph smaller.
206 ///
207 void Function::viewCFGOnly() const {
208   ViewGraph(this, "cfg" + getNameStr(), true);
209 }
210 
211 FunctionPass *llvm::createCFGPrinterPass () {
212   return new CFGPrinter();
213 }
214 
215 FunctionPass *llvm::createCFGOnlyPrinterPass () {
216   return new CFGOnlyPrinter();
217 }
218 
219