Add a function to compute loop nesting level to HBasicBlock.

src/hydrogen.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 84 matching lines @@
   void DetachLoopInformation();
   bool IsLoopHeader() const { return loop_information() != NULL; }
   bool IsStartBlock() const { return block_id() == 0; }
   void PostProcessLoopHeader(IterationStatement* stmt);
 
   bool IsFinished() const { return end_ != NULL; }
   void AddPhi(HPhi* phi);
   void RemovePhi(HPhi* phi);
   void AddInstruction(HInstruction* instr);
   bool Dominates(HBasicBlock* other) const;
+  int LoopNestingDepth() const;
 
   void SetInitialEnvironment(HEnvironment* env);
   void ClearEnvironment() { last_environment_ = NULL; }
   bool HasEnvironment() const { return last_environment_ != NULL; }
   void UpdateEnvironment(HEnvironment* env) { last_environment_ = env; }
   HBasicBlock* parent_loop_header() const { return parent_loop_header_; }
 
   void set_parent_loop_header(HBasicBlock* block) {
     ASSERT(parent_loop_header_ == NULL);
     parent_loop_header_ = block;
@@ skipping 1116 matching lines @@
   const char* filename_;
   HeapStringAllocator string_allocator_;
   StringStream trace_;
   int indent_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_H_