Implement the Function::viewCFG* methods, for use in a debugger. Also, the

-print-cfg pass now lives here.

llvm-svn: 9374

llvm/lib/Analysis/CFGPrinter.cpp

@@ -0,0 +1,144 @@
+//===- CFGPrinter.cpp - DOT printer for the control flow graph ------------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This file defines a '-print-cfg' analysis pass, which emits the
+// cfg.<fnname>.dot file for each function in the program, with a graph of the
+// CFG for that function.
+//
+// The other main feature of this file is that it implements the
+// Function::viewCFG method, which is useful for debugging passes which operate
+// on the CFG.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Support/GraphWriter.h"
+#include "llvm/Pass.h"
+#include "llvm/Function.h"
+#include "llvm/iTerminators.h"
+#include "llvm/Support/CFG.h"
+#include <sstream>
+#include <fstream>
+
+/// CFGOnly flag - This is used to control whether or not the CFG graph printer
+/// prints out the contents of basic blocks or not.  This is acceptable because
+/// this code is only really used for debugging purposes.
+///
+static bool CFGOnly = false;
+
+template<>
+struct DOTGraphTraits<const Function*> : public DefaultDOTGraphTraits {
+  static std::string getGraphName(const Function *F) {
+    return "CFG for '" + F->getName() + "' function";
+  }
+
+  static std::string getNodeLabel(const BasicBlock *Node,
+                                  const Function *Graph) {
+    if (CFGOnly) return Node->getName() + ":";
+
+    std::ostringstream Out;
+    Out << *Node;
+    std::string OutStr = Out.str();
+    if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
+
+    // Process string output to make it nicer...
+    for (unsigned i = 0; i != OutStr.length(); ++i)
+      if (OutStr[i] == '\n') {                            // Left justify
+        OutStr[i] = '\\';
+        OutStr.insert(OutStr.begin()+i+1, 'l');
+      } else if (OutStr[i] == ';') {                      // Delete comments!
+        unsigned Idx = OutStr.find('\n', i+1);            // Find end of line
+        OutStr.erase(OutStr.begin()+i, OutStr.begin()+Idx);
+        --i;
+      }
+
+    return OutStr;
+  }
+
+  static std::string getNodeAttributes(const BasicBlock *N) {
+    return "fontname=Courier";
+  }
+  
+  static std::string getEdgeSourceLabel(const BasicBlock *Node,
+                                        succ_const_iterator I) {
+    // Label source of conditional branches with "T" or "F"
+    if (const BranchInst *BI = dyn_cast<BranchInst>(Node->getTerminator()))
+      if (BI->isConditional())
+        return (I == succ_begin(Node)) ? "T" : "F";
+    return "";
+  }
+};
+
+namespace {
+  struct CFGPrinter : public FunctionPass {
+    virtual bool runOnFunction(Function &F) {
+      std::string Filename = "cfg." + F.getName() + ".dot";
+      std::cerr << "Writing '" << Filename << "'...";
+      std::ofstream File(Filename.c_str());
+      
+      if (File.good())
+        WriteGraph(File, (const Function*)&F);
+      else
+        std::cerr << "  error opening file for writing!";
+      std::cerr << "\n";
+      return false;
+    }
+
+    void print(std::ostream &OS) const {}
+    
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesAll();
+    }
+  };
+
+  RegisterAnalysis<CFGPrinter> P1("print-cfg",
+                                  "Print CFG of function to 'dot' file");
+};
+
+
+
+
+/// viewCFG - This function is meant for use from the debugger.  You can just
+/// say 'call F->viewCFG()' and a ghostview window should pop up from the
+/// program, displaying the CFG of the current function.  This depends on there
+/// being a 'dot' and 'gv' program in your path.
+///
+void Function::viewCFG() const {
+  std::string Filename = "/tmp/cfg." + getName() + ".dot";
+  std::cerr << "Writing '" << Filename << "'... ";
+  std::ofstream F(Filename.c_str());
+  
+  if (!F.good()) {
+    std::cerr << "  error opening file for writing!\n";
+    return;
+  }
+
+  WriteGraph(F, this);
+  F.close();
+  std::cerr << "\n";
+
+  std::cerr << "Running 'dot' program... " << std::flush;
+  if (system(("dot -Tps " + Filename + " > /tmp/cfg.tempgraph.ps").c_str())) {
+    std::cerr << "Error running dot: 'dot' not in path?\n";
+  } else {
+    std::cerr << "\n";
+    system("gv /tmp/cfg.tempgraph.ps");
+  }
+  system(("rm " + Filename + " /tmp/cfg.tempgraph.ps").c_str());
+}
+
+/// viewCFGOnly - This function is meant for use from the debugger.  It works
+/// just like viewCFG, but it does not include the contents of basic blocks
+/// into the nodes, just the label.  If you are only interested in the CFG t
+/// his can make the graph smaller.
+///
+void Function::viewCFGOnly() const {
+  CFGOnly = true;
+  viewCFG();
+  CFGOnly = false;
+}