Ensure double arrays are filled with holes when extended from variations of empty arrays.

src/ia32/stub-cache-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4335 matching lines @@
     int size = FixedDoubleArray::SizeFor(JSArray::kPreallocatedArrayElements);
     __ AllocateInNewSpace(size, edi, ebx, ecx, &prepare_slow, TAG_OBJECT);
 
     // Restore the key, which is known to be the array length.
     __ mov(ecx, Immediate(0));
 
     // eax: value
     // ecx: key
     // edx: receiver
     // edi: elements
-    // Initialize the new FixedDoubleArray. Leave elements unitialized for
-    // efficiency, they are guaranteed to be initialized before use.
+    // Initialize the new FixedDoubleArray.
     __ mov(FieldOperand(edi, JSObject::kMapOffset),
            Immediate(masm->isolate()->factory()->fixed_double_array_map()));
     __ mov(FieldOperand(edi, FixedDoubleArray::kLengthOffset),
            Immediate(Smi::FromInt(JSArray::kPreallocatedArrayElements)));
 
+    for (int i = 1; i < JSArray::kPreallocatedArrayElements; i++) {
+      int offset = FixedDoubleArray::OffsetOfElementAt(i);
+      __ mov(FieldOperand(edi, offset), Immediate(kHoleNanLower32));
+      __ mov(FieldOperand(edi, offset + kPointerSize),
+             Immediate(kHoleNanUpper32));
+    }
+
+    __ StoreNumberToDoubleElements(eax, edi, ecx, ebx, xmm0,
+                                   &transition_elements_kind, true);
+
     // Install the new backing store in the JSArray.
     __ mov(FieldOperand(edx, JSObject::kElementsOffset), edi);
     __ RecordWriteField(edx, JSObject::kElementsOffset, edi, ebx,
                         kDontSaveFPRegs, EMIT_REMEMBERED_SET, OMIT_SMI_CHECK);
 
     // Increment the length of the array.
     __ add(FieldOperand(edx, JSArray::kLengthOffset),
            Immediate(Smi::FromInt(1)));
     __ mov(edi, FieldOperand(edx, JSObject::kElementsOffset));
-    __ jmp(&finish_store);
+    __ ret(0);
 
     __ bind(&check_capacity);
     // eax: value
     // ecx: key
     // edx: receiver
     // edi: elements
     // Make sure that the backing store can hold additional elements.
     __ cmp(ecx, FieldOperand(edi, FixedDoubleArray::kLengthOffset));
     __ j(above_equal, &slow);
 
@@ skipping 11 matching lines @@
     __ jmp(ic_slow, RelocInfo::CODE_TARGET);
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32