[es6] When comparing two symbols we may need to throw a TypeError

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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
@@ skipping 1560 matching lines @@
     // so we do the second best thing - test it ourselves.
     Label heap_number;
     // If it's not a heap number, then return equal for (in)equality operator.
     __ Cmp(FieldOperand(rdx, HeapObject::kMapOffset),
            factory->heap_number_map());
     __ j(equal, &heap_number, Label::kNear);
     if (cc != equal) {
       // Call runtime on identical objects.  Otherwise return equal.
       __ CmpObjectType(rax, FIRST_SPEC_OBJECT_TYPE, rcx);
       __ j(above_equal, &not_identical, Label::kNear);
+      // Call runtime on identical symbols since we need to throw a TypeError.
+      __ CmpObjectType(rax, SYMBOL_TYPE, rcx);
+      __ j(equal, &not_identical, Label::kNear);
     }
     __ Set(rax, EQUAL);
     __ ret(0);
 
     __ bind(&heap_number);
     // It is a heap number, so return  equal if it's not NaN.
     // For NaN, return 1 for every condition except greater and
     // greater-equal.  Return -1 for them, so the comparison yields
     // false for all conditions except not-equal.
     __ Set(rax, EQUAL);
@@ skipping 3759 matching lines @@
   CallApiFunctionAndReturn(masm, api_function_address, thunk_ref, getter_arg,
                            kStackSpace, nullptr, return_value_operand, NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64