Add flow graph printing into a .cfg file with flag --print-flow-graph-file.

vm/il_printer.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_IL_PRINTER_H_
 #define VM_IL_PRINTER_H_
 
 #include "vm/intermediate_language.h"
 
 namespace dart {
 
 class BufferFormatter : public ValueObject {
  public:
   BufferFormatter(char* buffer, intptr_t size)
     : position_(0),
       buffer_(buffer),
       size_(size) { }
 
+  void VPrint(const char* format, va_list args);
   void Print(const char* format, ...);
 
  private:
   intptr_t position_;
   char* buffer_;
   const intptr_t size_;
 
   DISALLOW_COPY_AND_ASSIGN(BufferFormatter);
 };
 
 
 // Graph printing.
 class FlowGraphPrinter : public ValueObject {
  public:
   FlowGraphPrinter(const Function& function,
                    const GrowableArray<BlockEntryInstr*>& block_order)
       : function_(function), block_order_(block_order) { }
 
-  virtual ~FlowGraphPrinter() {}
-
   // Print the instructions in a block terminated by newlines.  Add "goto N"
   // to the end of the block if it ends with an unconditional jump to
   // another block and that block is not next in reverse postorder.
   void PrintBlocks();
   static void PrintInstruction(Instruction* instr);
   static void PrintComputation(Computation* comp);
 
  private:
   const Function& function_;
   const GrowableArray<BlockEntryInstr*>& block_order_;
 };
 
+
+class FlowGraphVisualizer : public ValueObject {
+ public:
+  FlowGraphVisualizer(const Function& function,
+                      const GrowableArray<BlockEntryInstr*>& block_order)
+      : function_(function), block_order_(block_order), indent_(0) { }
+
+  void PrintFunction();
+
+ private:
+  // Helpers for printing.
+  void PrintInstruction(Instruction* instr);
+  void Print(const char* format, ...);
+
+  const Function& function_;
+  const GrowableArray<BlockEntryInstr*>& block_order_;
+  intptr_t indent_;
+
+  DISALLOW_COPY_AND_ASSIGN(FlowGraphVisualizer);
+};
+
 }  // namespace dart
 
 #endif  // VM_IL_PRINTER_H_