Refactor and improve inlined double-aligned allocations

src/x64/code-stubs-x64.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 315 matching lines @@
   int elements_size = 0;
   if (length > 0) {
     elements_size = mode == FastCloneShallowArrayStub::CLONE_DOUBLE_ELEMENTS
         ? FixedDoubleArray::SizeFor(length)
         : FixedArray::SizeFor(length);
   }
   int size = JSArray::kSize + elements_size;
 
   // Allocate both the JS array and the elements array in one big
   // allocation. This avoids multiple limit checks.
-  __ AllocateInNewSpace(size, rax, rbx, rdx, fail, TAG_OBJECT);
+  AllocationFlags flags = TAG_OBJECT;
+  if (mode == FastCloneShallowArrayStub::CLONE_DOUBLE_ELEMENTS) {
+    flags = static_cast<AllocationFlags>(DOUBLE_ALIGNMENT | flags);
+  }
+  __ AllocateInNewSpace(size, rax, rbx, rdx, fail, flags);
 
   // Copy the JS array part.
   for (int i = 0; i < JSArray::kSize; i += kPointerSize) {
     if ((i != JSArray::kElementsOffset) || (length == 0)) {
       __ movq(rbx, FieldOperand(rcx, i));
       __ movq(FieldOperand(rax, i), rbx);
     }
   }
 
   if (length > 0) {
@@ skipping 6134 matching lines @@
 #endif
 
   __ Ret();
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64