[Interpreter] Adds support for const/let variables to interpreter.

src/interpreter/bytecode-generator.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_BYTECODE_GENERATOR_H_
 #define V8_INTERPRETER_BYTECODE_GENERATOR_H_
 
 #include "src/ast/ast.h"
 #include "src/interpreter/bytecode-array-builder.h"
 #include "src/interpreter/bytecodes.h"
@@ skipping 56 matching lines @@
   void VisitPropertyLoadForAccumulator(Register obj, Property* expr);
 
   void VisitVariableLoad(Variable* variable, FeedbackVectorSlot slot,
                          TypeofMode typeof_mode = NOT_INSIDE_TYPEOF);
   void VisitVariableLoadForAccumulatorValue(
       Variable* variable, FeedbackVectorSlot slot,
       TypeofMode typeof_mode = NOT_INSIDE_TYPEOF);
   MUST_USE_RESULT Register
   VisitVariableLoadForRegisterValue(Variable* variable, FeedbackVectorSlot slot,
                                     TypeofMode typeof_mode = NOT_INSIDE_TYPEOF);
-  void VisitVariableAssignment(Variable* variable, FeedbackVectorSlot slot);
+  void VisitVariableAssignment(Variable* variable, Token::Value op,
+                               FeedbackVectorSlot slot);
+  void BuildThrowIfHole(Handle<String> name);
+  void BuildThrowIfNotHole(Handle<String> name);
+  void BuildThrowReassignConstant(Register destination, Handle<String> name);
+  void BuildThrowReassignConstant(Handle<String> name);
+  void BuildHoleCheckForVariableLoad(VariableMode mode, Handle<String> name);
 
   void VisitArgumentsObject(Variable* variable);
   void VisitThisFunctionVariable(Variable* variable);
   void VisitNewTargetVariable(Variable* variable);
   void VisitNewLocalFunctionContext();
   void VisitBuildLocalActivationContext();
   void VisitBlockDeclarationsAndStatements(Block* stmt);
   void VisitNewLocalBlockContext(Scope* scope);
   void VisitNewLocalCatchContext(Variable* variable);
   void VisitFunctionClosureForContext();
@@ skipping 62 matching lines @@
   ContextScope* execution_context_;
   ExpressionResultScope* execution_result_;
   RegisterAllocationScope* register_allocator_;
 };
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_BYTECODE_GENERATOR_H_