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 using namespace llvm;
29 
30 namespace llvm {
31 template<>
32 struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
33   static std::string getGraphName(const Function *F) {
34     return "CFG for '" + F->getNameStr() + "' function";
35   }
36 
37   static std::string getNodeLabel(const BasicBlock *Node,
38                                   const Function *Graph,
39                                   bool ShortNames) {
40     if (ShortNames && !Node->getName().empty())
41       return Node->getNameStr() + ":";
42 
43     std::string Str;
44     raw_string_ostream OS(Str);
45 
46     if (ShortNames) {
47       WriteAsOperand(OS, Node, false);
48       return OS.str();
49     }
50 
51     if (Node->getName().empty()) {
52       WriteAsOperand(OS, Node, false);
53       OS << ":";
54     }
55 
56     OS << *Node;
57     std::string OutStr = OS.str();
58     if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
59 
60     // Process string output to make it nicer...
61     for (unsigned i = 0; i != OutStr.length(); ++i)
62       if (OutStr[i] == '\n') {                            // Left justify
63         OutStr[i] = '\\';
64         OutStr.insert(OutStr.begin()+i+1, 'l');
65       } else if (OutStr[i] == ';') {                      // Delete comments!
66         unsigned Idx = OutStr.find('\n', i+1);            // Find end of line
67         OutStr.erase(OutStr.begin()+i, OutStr.begin()+Idx);
68         --i;
69       }
70 
71     return OutStr;
72   }
73 
74   static std::string getEdgeSourceLabel(const BasicBlock *Node,
75                                         succ_const_iterator I) {
76     // Label source of conditional branches with "T" or "F"
77     if (const BranchInst *BI = dyn_cast<BranchInst>(Node->getTerminator()))
78       if (BI->isConditional())
79         return (I == succ_begin(Node)) ? "T" : "F";
80     return "";
81   }
82 };
83 }
84 
85 namespace {
86   struct VISIBILITY_HIDDEN CFGViewer : public FunctionPass {
87     static char ID; // Pass identifcation, replacement for typeid
88     CFGViewer() : FunctionPass(&ID) {}
89 
90     virtual bool runOnFunction(Function &F) {
91       F.viewCFG();
92       return false;
93     }
94 
95     void print(raw_ostream &OS, const Module* = 0) const {}
96 
97     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
98       AU.setPreservesAll();
99     }
100   };
101 }
102 
103 char CFGViewer::ID = 0;
104 static RegisterPass<CFGViewer>
105 V0("view-cfg", "View CFG of function", false, true);
106 
107 namespace {
108   struct VISIBILITY_HIDDEN CFGOnlyViewer : public FunctionPass {
109     static char ID; // Pass identifcation, replacement for typeid
110     CFGOnlyViewer() : FunctionPass(&ID) {}
111 
112     virtual bool runOnFunction(Function &F) {
113       F.viewCFG();
114       return false;
115     }
116 
117     void print(raw_ostream &OS, const Module* = 0) const {}
118 
119     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
120       AU.setPreservesAll();
121     }
122   };
123 }
124 
125 char CFGOnlyViewer::ID = 0;
126 static RegisterPass<CFGOnlyViewer>
127 V1("view-cfg-only",
128    "View CFG of function (with no function bodies)", false, true);
129 
130 namespace {
131   struct VISIBILITY_HIDDEN CFGPrinter : public FunctionPass {
132     static char ID; // Pass identification, replacement for typeid
133     CFGPrinter() : FunctionPass(&ID) {}
134     explicit CFGPrinter(void *pid) : FunctionPass(pid) {}
135 
136     virtual bool runOnFunction(Function &F) {
137       std::string Filename = "cfg." + F.getNameStr() + ".dot";
138       errs() << "Writing '" << Filename << "'...";
139 
140       std::string ErrorInfo;
141       raw_fd_ostream File(Filename.c_str(), ErrorInfo);
142 
143       if (ErrorInfo.empty())
144         WriteGraph(File, (const Function*)&F);
145       else
146         errs() << "  error opening file for writing!";
147       errs() << "\n";
148       return false;
149     }
150 
151     void print(raw_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       errs() << "Writing '" << Filename << "'...";
171 
172       std::string ErrorInfo;
173       raw_fd_ostream File(Filename.c_str(), ErrorInfo);
174 
175       if (ErrorInfo.empty())
176         WriteGraph(File, (const Function*)&F, true);
177       else
178         errs() << "  error opening file for writing!";
179       errs() << "\n";
180       return false;
181     }
182     void print(raw_ostream &OS, const Module* = 0) const {}
183 
184     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
185       AU.setPreservesAll();
186     }
187   };
188 }
189 
190 char CFGOnlyPrinter::ID = 0;
191 static RegisterPass<CFGOnlyPrinter>
192 P2("dot-cfg-only",
193    "Print CFG of function to 'dot' file (with no function bodies)", false, true);
194 
195 /// viewCFG - This function is meant for use from the debugger.  You can just
196 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
197 /// program, displaying the CFG of the current function.  This depends on there
198 /// being a 'dot' and 'gv' program in your path.
199 ///
200 void Function::viewCFG() const {
201   ViewGraph(this, "cfg" + getNameStr());
202 }
203 
204 /// viewCFGOnly - This function is meant for use from the debugger.  It works
205 /// just like viewCFG, but it does not include the contents of basic blocks
206 /// into the nodes, just the label.  If you are only interested in the CFG t
207 /// his can make the graph smaller.
208 ///
209 void Function::viewCFGOnly() const {
210   ViewGraph(this, "cfg" + getNameStr(), true);
211 }
212 
213 FunctionPass *llvm::createCFGPrinterPass () {
214   return new CFGPrinter();
215 }
216 
217 FunctionPass *llvm::createCFGOnlyPrinterPass () {
218   return new CFGOnlyPrinter();
219 }
220 
221