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 static RegisterPass<CFGViewer>
45 V0("view-cfg", "View CFG of function", false, true);
46 
47 namespace {
48   struct CFGOnlyViewer : public FunctionPass {
49     static char ID; // Pass identifcation, replacement for typeid
50     CFGOnlyViewer() : FunctionPass(&ID) {}
51 
52     virtual bool runOnFunction(Function &F) {
53       F.viewCFGOnly();
54       return false;
55     }
56 
57     void print(raw_ostream &OS, const Module* = 0) const {}
58 
59     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
60       AU.setPreservesAll();
61     }
62   };
63 }
64 
65 char CFGOnlyViewer::ID = 0;
66 static RegisterPass<CFGOnlyViewer>
67 V1("view-cfg-only",
68    "View CFG of function (with no function bodies)", false, true);
69 
70 namespace {
71   struct CFGPrinter : public FunctionPass {
72     static char ID; // Pass identification, replacement for typeid
73     CFGPrinter() : FunctionPass(&ID) {}
74     explicit CFGPrinter(void *pid) : FunctionPass(pid) {}
75 
76     virtual bool runOnFunction(Function &F) {
77       std::string Filename = "cfg." + F.getNameStr() + ".dot";
78       errs() << "Writing '" << Filename << "'...";
79 
80       std::string ErrorInfo;
81       raw_fd_ostream File(Filename.c_str(), ErrorInfo);
82 
83       if (ErrorInfo.empty())
84         WriteGraph(File, (const Function*)&F);
85       else
86         errs() << "  error opening file for writing!";
87       errs() << "\n";
88       return false;
89     }
90 
91     void print(raw_ostream &OS, const Module* = 0) const {}
92 
93     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
94       AU.setPreservesAll();
95     }
96   };
97 }
98 
99 char CFGPrinter::ID = 0;
100 static RegisterPass<CFGPrinter>
101 P1("dot-cfg", "Print CFG of function to 'dot' file", false, true);
102 
103 namespace {
104   struct CFGOnlyPrinter : public FunctionPass {
105     static char ID; // Pass identification, replacement for typeid
106     CFGOnlyPrinter() : FunctionPass(&ID) {}
107     explicit CFGOnlyPrinter(void *pid) : FunctionPass(pid) {}
108     virtual bool runOnFunction(Function &F) {
109       std::string Filename = "cfg." + F.getNameStr() + ".dot";
110       errs() << "Writing '" << Filename << "'...";
111 
112       std::string ErrorInfo;
113       raw_fd_ostream File(Filename.c_str(), ErrorInfo);
114 
115       if (ErrorInfo.empty())
116         WriteGraph(File, (const Function*)&F, true);
117       else
118         errs() << "  error opening file for writing!";
119       errs() << "\n";
120       return false;
121     }
122     void print(raw_ostream &OS, const Module* = 0) const {}
123 
124     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
125       AU.setPreservesAll();
126     }
127   };
128 }
129 
130 char CFGOnlyPrinter::ID = 0;
131 static RegisterPass<CFGOnlyPrinter>
132 P2("dot-cfg-only",
133    "Print CFG of function to 'dot' file (with no function bodies)", false, true);
134 
135 /// viewCFG - This function is meant for use from the debugger.  You can just
136 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
137 /// program, displaying the CFG of the current function.  This depends on there
138 /// being a 'dot' and 'gv' program in your path.
139 ///
140 void Function::viewCFG() const {
141   ViewGraph(this, "cfg" + getNameStr());
142 }
143 
144 /// viewCFGOnly - This function is meant for use from the debugger.  It works
145 /// just like viewCFG, but it does not include the contents of basic blocks
146 /// into the nodes, just the label.  If you are only interested in the CFG t
147 /// his can make the graph smaller.
148 ///
149 void Function::viewCFGOnly() const {
150   ViewGraph(this, "cfg" + getNameStr(), true);
151 }
152 
153 FunctionPass *llvm::createCFGPrinterPass () {
154   return new CFGPrinter();
155 }
156 
157 FunctionPass *llvm::createCFGOnlyPrinterPass () {
158   return new CFGOnlyPrinter();
159 }
160 
161