[es6] Reintroduce the instanceof operator in the backends.

src/code-stub-assembler.h

 // Copyright 2016 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_CODE_STUB_ASSEMBLER_H_
 #define V8_CODE_STUB_ASSEMBLER_H_
 
 #include "src/compiler/code-assembler.h"
 #include "src/objects.h"
 
@@ skipping 227 matching lines @@
   void TryLookupProperty(compiler::Node* object, compiler::Node* map,
                          compiler::Node* instance_type, compiler::Node* name,
                          Label* if_found, Label* if_not_found,
                          Label* call_runtime);
 
   void TryLookupElement(compiler::Node* object, compiler::Node* map,
                         compiler::Node* instance_type, compiler::Node* index,
                         Label* if_found, Label* if_not_found,
                         Label* call_runtime);
 
+  // Instanceof helpers.
+  // ES6 section 7.3.19 OrdinaryHasInstance (C, O)
+  compiler::Node* OrdinaryHasInstance(compiler::Node* context,
+                                      compiler::Node* callable,
+                                      compiler::Node* object);
+
  private:
   compiler::Node* AllocateRawAligned(compiler::Node* size_in_bytes,
                                      AllocationFlags flags,
                                      compiler::Node* top_address,
                                      compiler::Node* limit_address);
   compiler::Node* AllocateRawUnaligned(compiler::Node* size_in_bytes,
                                        AllocationFlags flags,
                                        compiler::Node* top_adddress,
                                        compiler::Node* limit_address);
 
   static const int kElementLoopUnrollThreshold = 8;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CODE_STUB_ASSEMBLER_H_