// -- rsp[0] : return address
// -----------------------------------
// The fail label is not actually used since we do not allocate.
- Label allocated, cow_array, only_change_map, done;
+ Label allocated, new_backing_store, only_change_map, done;
// Check for empty arrays, which only require a map transition and no changes
// to the backing store.
__ CompareRoot(r8, Heap::kEmptyFixedArrayRootIndex);
__ j(equal, &only_change_map);
- // Check backing store for COW-ness. If the negative case, we do not have to
- // allocate a new array, since FixedArray and FixedDoubleArray do not differ
- // in size.
+ // Check backing store for COW-ness. For COW arrays we have to
+ // allocate a new backing store.
__ SmiToInteger32(r9, FieldOperand(r8, FixedDoubleArray::kLengthOffset));
__ CompareRoot(FieldOperand(r8, HeapObject::kMapOffset),
Heap::kFixedCOWArrayMapRootIndex);
- __ j(equal, &cow_array);
+ __ j(equal, &new_backing_store);
+ // Check if the backing store is in new-space. If not, we need to allocate
+ // a new one since the old one is in pointer-space.
+ // If in new space, we can reuse the old backing store because it is
+ // the same size.
+ __ JumpIfNotInNewSpace(r8, rdi, &new_backing_store);
+
__ movq(r14, r8); // Destination array equals source array.
- __ bind(&allocated);
// r8 : source FixedArray
// r9 : elements array length
// r14: destination FixedDoubleArray
__ LoadRoot(rdi, Heap::kFixedDoubleArrayMapRootIndex);
__ movq(FieldOperand(r14, HeapObject::kMapOffset), rdi);
+ __ bind(&allocated);
// Set transitioned map.
__ movq(FieldOperand(rdx, HeapObject::kMapOffset), rbx);
__ RecordWriteField(rdx,
// r15: the-hole NaN
__ jmp(&entry);
- // Allocate new array if the source array is a COW array.
- __ bind(&cow_array);
+ // Allocate new backing store.
+ __ bind(&new_backing_store);
__ lea(rdi, Operand(r9, times_pointer_size, FixedArray::kHeaderSize));
__ AllocateInNewSpace(rdi, r14, r11, r15, fail, TAG_OBJECT);
+ // Set backing store's map
+ __ LoadRoot(rdi, Heap::kFixedDoubleArrayMapRootIndex);
+ __ movq(FieldOperand(r14, HeapObject::kMapOffset), rdi);
// Set receiver's backing store.
__ movq(FieldOperand(rdx, JSObject::kElementsOffset), r14);
__ movq(r11, r14);