Store offset between fixed typed array base and data start in object

src/objects-inl.h

 // 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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 3815 matching lines @@
 void ExternalFloat64Array::set(int index, double value) {
   DCHECK((index >= 0) && (index < this->length()));
   double* ptr = static_cast<double*>(external_pointer());
   ptr[index] = value;
 }
 
 
 ACCESSORS(FixedTypedArrayBase, base_pointer, Object, kBasePointerOffset)
 
 
-void* FixedTypedArrayBase::DataPtr() {
-  return FIELD_ADDR(this, kDataOffset);
+void* FixedTypedArrayBase::external_pointer() const {
+  intptr_t ptr = READ_INTPTR_FIELD(this, kExternalPointerOffset);
+  return reinterpret_cast<void*>(ptr);
 }
 
 
+void FixedTypedArrayBase::set_external_pointer(void* value,
+                                               WriteBarrierMode mode) {
+  intptr_t ptr = reinterpret_cast<intptr_t>(value);
+  WRITE_INTPTR_FIELD(this, kExternalPointerOffset, ptr);
+}
+
+
+void* FixedTypedArrayBase::DataPtr() {
+  return reinterpret_cast<void*>(
+      reinterpret_cast<intptr_t>(base_pointer()) +
+      reinterpret_cast<intptr_t>(external_pointer()));
+}
+
+
 int FixedTypedArrayBase::ElementSize(InstanceType type) {
   int element_size;
   switch (type) {
 #define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size)                       \
     case FIXED_##TYPE##_ARRAY_TYPE:                                           \
       element_size = size;                                                    \
       break;
 
     TYPED_ARRAYS(TYPED_ARRAY_CASE)
 #undef TYPED_ARRAY_CASE
@@ skipping 57 matching lines @@
 
 
 double Float64ArrayTraits::defaultValue() {
   return std::numeric_limits<double>::quiet_NaN();
 }
 
 
 template <class Traits>
 typename Traits::ElementType FixedTypedArray<Traits>::get_scalar(int index) {
   DCHECK((index >= 0) && (index < this->length()));
-  ElementType* ptr = reinterpret_cast<ElementType*>(
-      FIELD_ADDR(this, kDataOffset));
+  ElementType* ptr = reinterpret_cast<ElementType*>(DataPtr());
   return ptr[index];
 }
 
 
 template <class Traits>
 void FixedTypedArray<Traits>::set(int index, ElementType value) {
   DCHECK((index >= 0) && (index < this->length()));
-  ElementType* ptr = reinterpret_cast<ElementType*>(
-      FIELD_ADDR(this, kDataOffset));
+  ElementType* ptr = reinterpret_cast<ElementType*>(DataPtr());
   ptr[index] = value;
 }
 
 
 template <class Traits>
 typename Traits::ElementType FixedTypedArray<Traits>::from_int(int value) {
   return static_cast<ElementType>(value);
 }
 
 
@@ skipping 3361 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_