Refactor BasicBlock, no inheritance from GenericNode

src/compiler/instruction.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_INSTRUCTION_H_
 #define V8_COMPILER_INSTRUCTION_H_
 
 #include <deque>
 #include <map>
 #include <set>
@@ skipping 821 matching lines @@
 
   int BasicBlockCount() const {
     return static_cast<int>(schedule_->rpo_order()->size());
   }
 
   BasicBlock* BlockAt(int rpo_number) const {
     return (*schedule_->rpo_order())[rpo_number];
   }
 
   BasicBlock* GetContainingLoop(BasicBlock* block) {
-    return block->loop_header_;
+    return block->loop_header();
   }
 
-  int GetLoopEnd(BasicBlock* block) const { return block->loop_end_; }
+  int GetLoopEnd(BasicBlock* block) const { return block->loop_end(); }
 
   BasicBlock* GetBasicBlock(int instruction_index);
 
   int GetVirtualRegister(Node* node) const { return node->id(); }
 
   bool IsReference(int virtual_register) const;
   bool IsDouble(int virtual_register) const;
 
   void MarkAsReference(int virtual_register);
   void MarkAsDouble(int virtual_register);
@@ skipping 88 matching lines @@
   DeoptimizationVector deoptimization_entries_;
 };
 
 OStream& operator<<(OStream& os, const InstructionSequence& code);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_H_