Revert of Disallow subclassing Arrays.

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 2104 matching lines @@
   __ movp(rax, Immediate(arg_count()));
   __ movp(rcx, FieldOperand(rbx, rdx, times_pointer_size,
                             FixedArray::kHeaderSize));
   // Verify that ecx contains an AllocationSite
   Factory* factory = masm->isolate()->factory();
   __ Cmp(FieldOperand(rcx, HeapObject::kMapOffset),
          factory->allocation_site_map());
   __ j(not_equal, &miss);
 
   __ movp(rbx, rcx);
-  __ movp(rdx, rdi);
   ArrayConstructorStub stub(masm->isolate(), arg_count());
   __ TailCallStub(&stub);
 
   __ bind(&miss);
   GenerateMiss(masm);
 
   // The slow case, we need this no matter what to complete a call after a miss.
   CallFunctionNoFeedback(masm,
                          arg_count(),
                          true,
@@ skipping 2430 matching lines @@
     UNREACHABLE();
   }
 }
 
 
 void ArrayConstructorStub::Generate(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax    : argc
   //  -- rbx    : AllocationSite or undefined
   //  -- rdi    : constructor
-  //  -- rdx    : original constructor
   //  -- rsp[0] : return address
   //  -- rsp[8] : last argument
   // -----------------------------------
   if (FLAG_debug_code) {
     // The array construct code is only set for the global and natives
     // builtin Array functions which always have maps.
 
     // Initial map for the builtin Array function should be a map.
     __ movp(rcx, FieldOperand(rdi, JSFunction::kPrototypeOrInitialMapOffset));
     // Will both indicate a NULL and a Smi.
     STATIC_ASSERT(kSmiTag == 0);
     Condition not_smi = NegateCondition(masm->CheckSmi(rcx));
     __ Check(not_smi, kUnexpectedInitialMapForArrayFunction);
     __ CmpObjectType(rcx, MAP_TYPE, rcx);
     __ Check(equal, kUnexpectedInitialMapForArrayFunction);
 
     // We should either have undefined in rbx or a valid AllocationSite
     __ AssertUndefinedOrAllocationSite(rbx);
   }
 
-  Label subclassing;
-  __ cmpp(rdi, rdx);
-  __ j(not_equal, &subclassing);
-
   Label no_info;
   // If the feedback vector is the undefined value call an array constructor
   // that doesn't use AllocationSites.
   __ CompareRoot(rbx, Heap::kUndefinedValueRootIndex);
   __ j(equal, &no_info);
 
   // Only look at the lower 16 bits of the transition info.
   __ movp(rdx, FieldOperand(rbx, AllocationSite::kTransitionInfoOffset));
   __ SmiToInteger32(rdx, rdx);
   STATIC_ASSERT(AllocationSite::ElementsKindBits::kShift == 0);
   __ andp(rdx, Immediate(AllocationSite::ElementsKindBits::kMask));
   GenerateDispatchToArrayStub(masm, DONT_OVERRIDE);
 
   __ bind(&no_info);
   GenerateDispatchToArrayStub(masm, DISABLE_ALLOCATION_SITES);
-
-  __ bind(&subclassing);
-  __ TailCallRuntime(Runtime::kThrowArrayNotSubclassableError, 0, 1);
 }
 
 
 void InternalArrayConstructorStub::GenerateCase(
     MacroAssembler* masm, ElementsKind kind) {
   Label not_zero_case, not_one_case;
   Label normal_sequence;
 
   __ testp(rax, rax);
   __ j(not_zero, &not_zero_case);
@@ skipping 475 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