lib/Analysis/CFGPrinter.cpp

   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