Provide a tagged allocation top pointer.

src/arm/code-stubs-arm.cc

 // Copyright 2012 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_ARM
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 4315 matching lines @@
   // Fall back to runtime if the target differs from the new target's
   // initial map constructor.
   __ ldr(r0, FieldMemOperand(r2, Map::kConstructorOrBackPointerOffset));
   __ cmp(r0, r1);
   __ b(ne, &new_object);
 
   // Allocate the JSObject on the heap.
   Label allocate, done_allocate;
   __ ldrb(r4, FieldMemOperand(r2, Map::kInstanceSizeOffset));
   __ Allocate(r4, r0, r5, r6, &allocate, SIZE_IN_WORDS);
+  __ sub(r5, r5, Operand(kHeapObjectTag));  // Untag result end.
   __ bind(&done_allocate);
 
   // Initialize the JSObject fields.
   __ str(r2, FieldMemOperand(r0, JSObject::kMapOffset));
   __ LoadRoot(r3, Heap::kEmptyFixedArrayRootIndex);
   __ str(r3, FieldMemOperand(r0, JSObject::kPropertiesOffset));
   __ str(r3, FieldMemOperand(r0, JSObject::kElementsOffset));
   STATIC_ASSERT(JSObject::kHeaderSize == 3 * kPointerSize);
   __ add(r1, r0, Operand(JSObject::kHeaderSize - kHeapObjectTag));
 
@@ skipping 120 matching lines @@
   __ bind(&no_rest_parameters);
   {
     // ----------- S t a t e -------------
     //  -- cp : context
     //  -- lr : return address
     // -----------------------------------
 
     // Allocate an empty rest parameter array.
     Label allocate, done_allocate;
     __ Allocate(JSArray::kSize, r0, r1, r2, &allocate, NO_ALLOCATION_FLAGS);
+    __ sub(r1, r1, Operand(kHeapObjectTag));  // Untag result end.
     __ bind(&done_allocate);
 
     // Setup the rest parameter array in r0.
     __ LoadNativeContextSlot(Context::JS_ARRAY_FAST_ELEMENTS_MAP_INDEX, r1);
     __ str(r1, FieldMemOperand(r0, JSArray::kMapOffset));
     __ LoadRoot(r1, Heap::kEmptyFixedArrayRootIndex);
     __ str(r1, FieldMemOperand(r0, JSArray::kPropertiesOffset));
     __ str(r1, FieldMemOperand(r0, JSArray::kElementsOffset));
     __ mov(r1, Operand(0));
     __ str(r1, FieldMemOperand(r0, JSArray::kLengthOffset));
@@ skipping 880 matching lines @@
   CallApiFunctionAndReturn(masm, api_function_address, thunk_ref,
                            kStackUnwindSpace, NULL, return_value_operand, NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM