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/Analysis/CFGPrinter.h"
21 
22 #include "llvm/Pass.h"
23 using namespace llvm;
24 
25 namespace {
26   struct CFGViewer : public FunctionPass {
27     static char ID; // Pass identifcation, replacement for typeid
28     CFGViewer() : FunctionPass(ID) {}
29 
30     virtual bool runOnFunction(Function &F) {
31       F.viewCFG();
32       return false;
33     }
34 
35     void print(raw_ostream &OS, const Module* = 0) const {}
36 
37     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
38       AU.setPreservesAll();
39     }
40   };
41 }
42 
43 char CFGViewer::ID = 0;
44 INITIALIZE_PASS(CFGViewer, "view-cfg", "View CFG of function", false, true);
45 
46 namespace {
47   struct CFGOnlyViewer : public FunctionPass {
48     static char ID; // Pass identifcation, replacement for typeid
49     CFGOnlyViewer() : FunctionPass(ID) {}
50 
51     virtual bool runOnFunction(Function &F) {
52       F.viewCFGOnly();
53       return false;
54     }
55 
56     void print(raw_ostream &OS, const Module* = 0) const {}
57 
58     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
59       AU.setPreservesAll();
60     }
61   };
62 }
63 
64 char CFGOnlyViewer::ID = 0;
65 INITIALIZE_PASS(CFGOnlyViewer, "view-cfg-only",
66                 "View CFG of function (with no function bodies)", false, true);
67 
68 namespace {
69   struct CFGPrinter : public FunctionPass {
70     static char ID; // Pass identification, replacement for typeid
71     CFGPrinter() : FunctionPass(ID) {}
72     explicit CFGPrinter(char &pid) : FunctionPass(pid) {}
73 
74     virtual bool runOnFunction(Function &F) {
75       std::string Filename = "cfg." + F.getNameStr() + ".dot";
76       errs() << "Writing '" << Filename << "'...";
77 
78       std::string ErrorInfo;
79       raw_fd_ostream File(Filename.c_str(), ErrorInfo);
80 
81       if (ErrorInfo.empty())
82         WriteGraph(File, (const Function*)&F);
83       else
84         errs() << "  error opening file for writing!";
85       errs() << "\n";
86       return false;
87     }
88 
89     void print(raw_ostream &OS, const Module* = 0) const {}
90 
91     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
92       AU.setPreservesAll();
93     }
94   };
95 }
96 
97 char CFGPrinter::ID = 0;
98 INITIALIZE_PASS(CFGPrinter, "dot-cfg", "Print CFG of function to 'dot' file",
99                 false, true);
100 
101 namespace {
102   struct CFGOnlyPrinter : public FunctionPass {
103     static char ID; // Pass identification, replacement for typeid
104     CFGOnlyPrinter() : FunctionPass(ID) {}
105     explicit CFGOnlyPrinter(char &pid) : FunctionPass(pid) {}
106     virtual bool runOnFunction(Function &F) {
107       std::string Filename = "cfg." + F.getNameStr() + ".dot";
108       errs() << "Writing '" << Filename << "'...";
109 
110       std::string ErrorInfo;
111       raw_fd_ostream File(Filename.c_str(), ErrorInfo);
112 
113       if (ErrorInfo.empty())
114         WriteGraph(File, (const Function*)&F, true);
115       else
116         errs() << "  error opening file for writing!";
117       errs() << "\n";
118       return false;
119     }
120     void print(raw_ostream &OS, const Module* = 0) const {}
121 
122     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
123       AU.setPreservesAll();
124     }
125   };
126 }
127 
128 char CFGOnlyPrinter::ID = 0;
129 INITIALIZE_PASS(CFGOnlyPrinter, "dot-cfg-only",
130    "Print CFG of function to 'dot' file (with no function bodies)",
131    false, true);
132 
133 /// viewCFG - This function is meant for use from the debugger.  You can just
134 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
135 /// program, displaying the CFG of the current function.  This depends on there
136 /// being a 'dot' and 'gv' program in your path.
137 ///
138 void Function::viewCFG() const {
139   ViewGraph(this, "cfg" + getNameStr());
140 }
141 
142 /// viewCFGOnly - This function is meant for use from the debugger.  It works
143 /// just like viewCFG, but it does not include the contents of basic blocks
144 /// into the nodes, just the label.  If you are only interested in the CFG t
145 /// his can make the graph smaller.
146 ///
147 void Function::viewCFGOnly() const {
148   ViewGraph(this, "cfg" + getNameStr(), true);
149 }
150 
151 FunctionPass *llvm::createCFGPrinterPass () {
152   return new CFGPrinter();
153 }
154 
155 FunctionPass *llvm::createCFGOnlyPrinterPass () {
156   return new CFGOnlyPrinter();
157 }
158 
159