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 #include "llvm/Config/config.h"
  29 #include <iosfwd>
  30 #include <sstream>
  31 #include <fstream>
  32 using namespace llvm;
  33
  34 /// CFGOnly flag - This is used to control whether or not the CFG graph printer
  35 /// prints out the contents of basic blocks or not.  This is acceptable because
  36 /// this code is only really used for debugging purposes.
  37 ///
  38 static bool CFGOnly = false;
  39
  40 namespace llvm {
  41 template<>
  42 struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
  43   static std::string getGraphName(const Function *F) {
  44     return "CFG for '" + F->getName() + "' function";
  45   }
  46
  47   static std::string getNodeLabel(const BasicBlock *Node,
  48                                   const Function *Graph) {
  49     if (CFGOnly && !Node->getName().empty())
  50       return Node->getName() + ":";
  51
  52     std::ostringstream Out;
  53     if (CFGOnly) {
  54       WriteAsOperand(Out, Node, false);
  55       return Out.str();
  56     }
  57
  58     if (Node->getName().empty()) {
  59       WriteAsOperand(Out, Node, false);
  60       Out << ":";
  61     }
  62
  63     Out << *Node;
  64     std::string OutStr = Out.str();
  65     if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
  66
  67     // Process string output to make it nicer...
  68     for (unsigned i = 0; i != OutStr.length(); ++i)
  69       if (OutStr[i] == '\n') {                            // Left justify
  70         OutStr[i] = '\\';
  71         OutStr.insert(OutStr.begin()+i+1, 'l');
  72       } else if (OutStr[i] == ';') {                      // Delete comments!
  73         unsigned Idx = OutStr.find('\n', i+1);            // Find end of line
  74         OutStr.erase(OutStr.begin()+i, OutStr.begin()+Idx);
  75         --i;
  76       }
  77
  78     return OutStr;
  79   }
  80
  81   static std::string getEdgeSourceLabel(const BasicBlock *Node,
  82                                         succ_const_iterator I) {
  83     // Label source of conditional branches with "T" or "F"
  84     if (const BranchInst *BI = dyn_cast<BranchInst>(Node->getTerminator()))
  85       if (BI->isConditional())
  86         return (I == succ_begin(Node)) ? "T" : "F";
  87     return "";
  88   }
  89 };
  90 }
  91
  92 namespace {
  93   struct VISIBILITY_HIDDEN CFGViewer : public FunctionPass {
  94     static char ID; // Pass identifcation, replacement for typeid
  95     CFGViewer() : FunctionPass(&ID) {}
  96
  97     virtual bool runOnFunction(Function &F) {
  98       F.viewCFG();
  99       return false;
 100     }
 101
 102     void print(std::ostream &OS, const Module* = 0) const {}
 103
 104     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
 105       AU.setPreservesAll();
 106     }
 107   };
 108 }
 109
 110 char CFGViewer::ID = 0;
 111 static RegisterPass<CFGViewer>
 112 V0("view-cfg", "View CFG of function", false, true);
 113
 114 namespace {
 115   struct VISIBILITY_HIDDEN CFGOnlyViewer : public FunctionPass {
 116     static char ID; // Pass identifcation, replacement for typeid
 117     CFGOnlyViewer() : FunctionPass(&ID) {}
 118
 119     virtual bool runOnFunction(Function &F) {
 120       CFGOnly = true;
 121       F.viewCFG();
 122       CFGOnly = false;
 123       return false;
 124     }
 125
 126     void print(std::ostream &OS, const Module* = 0) const {}
 127
 128     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
 129       AU.setPreservesAll();
 130     }
 131   };
 132 }
 133
 134 char CFGOnlyViewer::ID = 0;
 135 static RegisterPass<CFGOnlyViewer>
 136 V1("view-cfg-only",
 137    "View CFG of function (with no function bodies)", false, true);
 138
 139 namespace {
 140   struct VISIBILITY_HIDDEN CFGPrinter : public FunctionPass {
 141     static char ID; // Pass identification, replacement for typeid
 142     CFGPrinter() : FunctionPass(&ID) {}
 143     explicit CFGPrinter(void *pid) : FunctionPass(pid) {}
 144
 145     virtual bool runOnFunction(Function &F) {
 146       std::string Filename = "cfg." + F.getName() + ".dot";
 147       cerr << "Writing '" << Filename << "'...";
 148       std::ofstream File(Filename.c_str());
 149
 150       if (File.good())
 151         WriteGraph(File, (const Function*)&F);
 152       else
 153         cerr << "  error opening file for writing!";
 154       cerr << "\n";
 155       return false;
 156     }
 157
 158     void print(std::ostream &OS, const Module* = 0) const {}
 159
 160     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
 161       AU.setPreservesAll();
 162     }
 163   };
 164 }
 165
 166 char CFGPrinter::ID = 0;
 167 static RegisterPass<CFGPrinter>
 168 P1("dot-cfg", "Print CFG of function to 'dot' file", false, true);
 169
 170 namespace {
 171   struct VISIBILITY_HIDDEN CFGOnlyPrinter : public CFGPrinter {
 172     static char ID; // Pass identification, replacement for typeid
 173     CFGOnlyPrinter() : CFGPrinter(&ID) {}
 174     virtual bool runOnFunction(Function &F) {
 175       bool OldCFGOnly = CFGOnly;
 176       CFGOnly = true;
 177       CFGPrinter::runOnFunction(F);
 178       CFGOnly = OldCFGOnly;
 179       return false;
 180     }
 181     void print(std::ostream &OS, const Module* = 0) const {}
 182
 183     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
 184       AU.setPreservesAll();
 185     }
 186   };
 187 }
 188
 189 char CFGOnlyPrinter::ID = 0;
 190 static RegisterPass<CFGOnlyPrinter>
 191 P2("dot-cfg-only",
 192    "Print CFG of function to 'dot' file (with no function bodies)", false, true);
 193
 194 /// viewCFG - This function is meant for use from the debugger.  You can just
 195 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
 196 /// program, displaying the CFG of the current function.  This depends on there
 197 /// being a 'dot' and 'gv' program in your path.
 198 ///
 199 void Function::viewCFG() const {
 200   ViewGraph(this, "cfg" + getName());
 201 }
 202
 203 /// viewCFGOnly - This function is meant for use from the debugger.  It works
 204 /// just like viewCFG, but it does not include the contents of basic blocks
 205 /// into the nodes, just the label.  If you are only interested in the CFG t
 206 /// his can make the graph smaller.
 207 ///
 208 void Function::viewCFGOnly() const {
 209   CFGOnly = true;
 210   viewCFG();
 211   CFGOnly = false;
 212 }
 213
 214 FunctionPass *llvm::createCFGPrinterPass () {
 215   return new CFGPrinter();
 216 }
 217
 218 FunctionPass *llvm::createCFGOnlyPrinterPass () {
 219   return new CFGOnlyPrinter();
 220 }
 221