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#include "llvm/Pass.h"
22#include "llvm/Support/FileSystem.h"
23using namespace llvm;
24
25namespace {
26  struct CFGViewer : public FunctionPass {
27    static char ID; // Pass identifcation, replacement for typeid
28    CFGViewer() : FunctionPass(ID) {
29      initializeCFGOnlyViewerPass(*PassRegistry::getPassRegistry());
30    }
31
32    bool runOnFunction(Function &F) override {
33      F.viewCFG();
34      return false;
35    }
36
37    void print(raw_ostream &OS, const Module* = nullptr) const override {}
38
39    void getAnalysisUsage(AnalysisUsage &AU) const override {
40      AU.setPreservesAll();
41    }
42  };
43}
44
45char CFGViewer::ID = 0;
46INITIALIZE_PASS(CFGViewer, "view-cfg", "View CFG of function", false, true)
47
48namespace {
49  struct CFGOnlyViewer : public FunctionPass {
50    static char ID; // Pass identifcation, replacement for typeid
51    CFGOnlyViewer() : FunctionPass(ID) {
52      initializeCFGOnlyViewerPass(*PassRegistry::getPassRegistry());
53    }
54
55    bool runOnFunction(Function &F) override {
56      F.viewCFGOnly();
57      return false;
58    }
59
60    void print(raw_ostream &OS, const Module* = nullptr) const override {}
61
62    void getAnalysisUsage(AnalysisUsage &AU) const override {
63      AU.setPreservesAll();
64    }
65  };
66}
67
68char CFGOnlyViewer::ID = 0;
69INITIALIZE_PASS(CFGOnlyViewer, "view-cfg-only",
70                "View CFG of function (with no function bodies)", false, true)
71
72namespace {
73  struct CFGPrinter : public FunctionPass {
74    static char ID; // Pass identification, replacement for typeid
75    CFGPrinter() : FunctionPass(ID) {
76      initializeCFGPrinterPass(*PassRegistry::getPassRegistry());
77    }
78
79    bool runOnFunction(Function &F) override {
80      std::string Filename = "cfg." + F.getName().str() + ".dot";
81      errs() << "Writing '" << Filename << "'...";
82
83      std::string ErrorInfo;
84      raw_fd_ostream File(Filename.c_str(), ErrorInfo, sys::fs::F_Text);
85
86      if (ErrorInfo.empty())
87        WriteGraph(File, (const Function*)&F);
88      else
89        errs() << "  error opening file for writing!";
90      errs() << "\n";
91      return false;
92    }
93
94    void print(raw_ostream &OS, const Module* = nullptr) const override {}
95
96    void getAnalysisUsage(AnalysisUsage &AU) const override {
97      AU.setPreservesAll();
98    }
99  };
100}
101
102char CFGPrinter::ID = 0;
103INITIALIZE_PASS(CFGPrinter, "dot-cfg", "Print CFG of function to 'dot' file",
104                false, true)
105
106namespace {
107  struct CFGOnlyPrinter : public FunctionPass {
108    static char ID; // Pass identification, replacement for typeid
109    CFGOnlyPrinter() : FunctionPass(ID) {
110      initializeCFGOnlyPrinterPass(*PassRegistry::getPassRegistry());
111    }
112
113    bool runOnFunction(Function &F) override {
114      std::string Filename = "cfg." + F.getName().str() + ".dot";
115      errs() << "Writing '" << Filename << "'...";
116
117      std::string ErrorInfo;
118      raw_fd_ostream File(Filename.c_str(), ErrorInfo, sys::fs::F_Text);
119
120      if (ErrorInfo.empty())
121        WriteGraph(File, (const Function*)&F, true);
122      else
123        errs() << "  error opening file for writing!";
124      errs() << "\n";
125      return false;
126    }
127    void print(raw_ostream &OS, const Module* = nullptr) const override {}
128
129    void getAnalysisUsage(AnalysisUsage &AU) const override {
130      AU.setPreservesAll();
131    }
132  };
133}
134
135char CFGOnlyPrinter::ID = 0;
136INITIALIZE_PASS(CFGOnlyPrinter, "dot-cfg-only",
137   "Print CFG of function to 'dot' file (with no function bodies)",
138   false, true)
139
140/// viewCFG - This function is meant for use from the debugger.  You can just
141/// say 'call F->viewCFG()' and a ghostview window should pop up from the
142/// program, displaying the CFG of the current function.  This depends on there
143/// being a 'dot' and 'gv' program in your path.
144///
145void Function::viewCFG() const {
146  ViewGraph(this, "cfg" + getName());
147}
148
149/// viewCFGOnly - This function is meant for use from the debugger.  It works
150/// just like viewCFG, but it does not include the contents of basic blocks
151/// into the nodes, just the label.  If you are only interested in the CFG
152/// this can make the graph smaller.
153///
154void Function::viewCFGOnly() const {
155  ViewGraph(this, "cfg" + getName(), true);
156}
157
158FunctionPass *llvm::createCFGPrinterPass () {
159  return new CFGPrinter();
160}
161
162FunctionPass *llvm::createCFGOnlyPrinterPass () {
163  return new CFGOnlyPrinter();
164}
165
166