[interpreter] Add explicit OSR polling bytecode.

src/interpreter/interpreter-assembler.h

 // Copyright 2015 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_INTERPRETER_INTERPRETER_ASSEMBLER_H_
 #define V8_INTERPRETER_INTERPRETER_ASSEMBLER_H_
 
 #include "src/allocation.h"
 #include "src/base/smart-pointers.h"
 #include "src/builtins/builtins.h"
@@ skipping 128 matching lines @@
   // word values |lhs| and |rhs| are not equal.
   void JumpIfWordNotEqual(compiler::Node* lhs, compiler::Node* rhs,
                           compiler::Node* jump_offset);
 
   // Returns true if the stack guard check triggers an interrupt.
   compiler::Node* StackCheckTriggeredInterrupt();
 
   // Updates the profiler interrupt budget for a return.
   void UpdateInterruptBudgetOnReturn();
 
+  // Returns the OSR nesting level from the bytecode header.
+  compiler::Node* LoadOSRNestingLevel();
+
   // Dispatch to the bytecode.
   compiler::Node* Dispatch();
 
   // Dispatch to bytecode handler.
   compiler::Node* DispatchToBytecodeHandler(compiler::Node* handler) {
     return DispatchToBytecodeHandler(handler, BytecodeOffset());
   }
 
   // Dispatch bytecode as wide operand variant.
   void DispatchWide(OperandScale operand_scale);
@@ skipping 119 matching lines @@
   compiler::Node* stack_pointer_before_call_;
 
   DISALLOW_COPY_AND_ASSIGN(InterpreterAssembler);
 };
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_INTERPRETER_ASSEMBLER_H_