Optimize array literal boilerplate copy for fast cases.

src/x64/code-stubs-x64.cc

 // Copyright 2011 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 208 matching lines @@
 }
 
 
 static void GenerateFastCloneShallowArrayCommon(
     MacroAssembler* masm,
     int length,
     FastCloneShallowArrayStub::Mode mode,
     Label* fail) {
   // Registers on entry:
   //
-  // rcx: boilerplate array.
+  // rcx: boilerplate literal array.
   ASSERT(mode != FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS);
 
   // All sizes here are multiples of kPointerSize.
   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;
@@ skipping 68 matching lines @@
            factory->fixed_cow_array_map());
     __ j(not_equal, &check_fast_elements);
     GenerateFastCloneShallowArrayCommon(masm, 0,
                                         COPY_ON_WRITE_ELEMENTS, &slow_case);
     __ ret(3 * kPointerSize);
 
     __ bind(&check_fast_elements);
     __ Cmp(FieldOperand(rbx, HeapObject::kMapOffset),
            factory->fixed_array_map());
     __ j(not_equal, &double_elements);
-    GenerateFastCloneShallowArrayCommon(masm, 0,
+    GenerateFastCloneShallowArrayCommon(masm, length_,
                                         CLONE_ELEMENTS, &slow_case);
     __ ret(3 * kPointerSize);
 
     __ bind(&double_elements);
     mode = CLONE_DOUBLE_ELEMENTS;
     // Fall through to generate the code to handle double elements.
   }
 
   if (FLAG_debug_code) {
     const char* message;
@@ skipping 10 matching lines @@
       expected_map_index = Heap::kFixedCOWArrayMapRootIndex;
     }
     __ push(rcx);
     __ movq(rcx, FieldOperand(rcx, JSArray::kElementsOffset));
     __ CompareRoot(FieldOperand(rcx, HeapObject::kMapOffset),
                    expected_map_index);
     __ Assert(equal, message);
     __ pop(rcx);
   }
 
-  GenerateFastCloneShallowArrayCommon(masm, 0,
-                                      CLONE_DOUBLE_ELEMENTS, &slow_case);
+  GenerateFastCloneShallowArrayCommon(masm, length_, mode, &slow_case);
   __ ret(3 * kPointerSize);
 
   __ bind(&slow_case);
   __ TailCallRuntime(Runtime::kCreateArrayLiteralShallow, 3, 1);
 }
 
 
 // The stub expects its argument on the stack and returns its result in tos_:
 // zero for false, and a non-zero value for true.
 void ToBooleanStub::Generate(MacroAssembler* masm) {
@@ skipping 5701 matching lines @@
                                  xmm0,
                                  &slow_elements);
   __ ret(0);
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64