Revert of Disallow subclassing Arrays.

src/arm64/code-stubs-arm64.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_ARM64
 
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
@@ skipping 3053 matching lines @@
          Operand::UntagSmiAndScale(index, kPointerSizeLog2));
   __ Ldr(scratch, FieldMemOperand(scratch, FixedArray::kHeaderSize));
 
   // Verify that scratch contains an AllocationSite
   Register map = x5;
   __ Ldr(map, FieldMemOperand(scratch, HeapObject::kMapOffset));
   __ JumpIfNotRoot(map, Heap::kAllocationSiteMapRootIndex, &miss);
 
   Register allocation_site = feedback_vector;
   __ Mov(allocation_site, scratch);
-
-  Register original_constructor = x3;
-  __ Mov(original_constructor, function);
   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 1915 matching lines @@
   }
 }
 
 
 void ArrayConstructorStub::Generate(MacroAssembler* masm) {
   ASM_LOCATION("ArrayConstructorStub::Generate");
   // ----------- S t a t e -------------
   //  -- x0 : argc (only if argument_count() == ANY)
   //  -- x1 : constructor
   //  -- x2 : AllocationSite or undefined
-  //  -- x3 : original constructor
   //  -- sp[0] : return address
   //  -- sp[4] : last argument
   // -----------------------------------
   Register constructor = x1;
   Register allocation_site = x2;
-  Register original_constructor = x3;
 
   if (FLAG_debug_code) {
     // The array construct code is only set for the global and natives
     // builtin Array functions which always have maps.
 
     Label unexpected_map, map_ok;
     // Initial map for the builtin Array function should be a map.
     __ Ldr(x10, FieldMemOperand(constructor,
                                 JSFunction::kPrototypeOrInitialMapOffset));
     // Will both indicate a NULL and a Smi.
     __ JumpIfSmi(x10, &unexpected_map);
     __ JumpIfObjectType(x10, x10, x11, MAP_TYPE, &map_ok);
     __ Bind(&unexpected_map);
     __ Abort(kUnexpectedInitialMapForArrayFunction);
     __ Bind(&map_ok);
 
     // We should either have undefined in the allocation_site register or a
     // valid AllocationSite.
     __ AssertUndefinedOrAllocationSite(allocation_site, x10);
   }
 
-  Label subclassing;
-  __ Cmp(original_constructor, constructor);
-  __ B(ne, &subclassing);
-
   Register kind = x3;
   Label no_info;
   // Get the elements kind and case on that.
   __ JumpIfRoot(allocation_site, Heap::kUndefinedValueRootIndex, &no_info);
 
   __ Ldrsw(kind,
            UntagSmiFieldMemOperand(allocation_site,
                                    AllocationSite::kTransitionInfoOffset));
   __ And(kind, kind, 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 zero_case, n_case;
   Register argc = x0;
 
   __ Cbz(argc, &zero_case);
   __ CompareAndBranch(argc, 1, ne, &n_case);
@@ skipping 423 matching lines @@
                            kStackUnwindSpace, NULL, spill_offset,
                            MemOperand(fp, 6 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM64