[runtime] Introduce dedicated JSBoundFunction to represent bound functions.

src/x64/code-stubs-x64.cc

 // Copyright 2013 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
 #include "src/ic/handler-compiler.h"
@@ skipping 2493 matching lines @@
   __ bind(&fast_case);
   __ JumpIfSmi(function, &slow_case);
   __ CmpObjectType(function, JS_FUNCTION_TYPE, function_map);
   __ j(not_equal, &slow_case);
 
   // Ensure that {function} has an instance prototype.
   __ testb(FieldOperand(function_map, Map::kBitFieldOffset),
            Immediate(1 << Map::kHasNonInstancePrototype));
   __ j(not_zero, &slow_case);
 
-  // Ensure that {function} is not bound.
-  Register const shared_info = kScratchRegister;
-  __ movp(shared_info,
-          FieldOperand(function, JSFunction::kSharedFunctionInfoOffset));
-  __ TestBitSharedFunctionInfoSpecialField(
-      shared_info, SharedFunctionInfo::kCompilerHintsOffset,
-      SharedFunctionInfo::kBoundFunction);
-  __ j(not_zero, &slow_case);
-
   // Get the "prototype" (or initial map) of the {function}.
   __ movp(function_prototype,
           FieldOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
   __ AssertNotSmi(function_prototype);
 
   // Resolve the prototype if the {function} has an initial map.  Afterwards the
   // {function_prototype} will be either the JSReceiver prototype object or the
   // hole value, which means that no instances of the {function} were created so
   // far and hence we should return false.
   Label function_prototype_valid;
@@ skipping 2892 matching lines @@
                            kStackSpace, nullptr, return_value_operand, NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64