Port FastCloneShallowArrayStub to ARM and x64.

src/ia32/codegen-ia32.cc

 // Copyright 2010 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 6899 matching lines @@
   __ mov(esi, Operand(eax));
   __ ret(1 * kPointerSize);
 
   // Need to collect. Call into runtime system.
   __ bind(&gc);
   __ TailCallRuntime(ExternalReference(Runtime::kNewContext), 1, 1);
 }
 
 
 void FastCloneShallowArrayStub::Generate(MacroAssembler* masm) {
+  // Stack layout on entry:
+  //
+  // [esp + kPointerSize]: constant elements.
+  // [esp + (2 * kPointerSize)]: literal index.
+  // [esp + (3 * kPointerSize)]: literals array.
+
+  // All sizes here are multiples of kPointerSize.
   int elements_size = (length_ > 0) ? FixedArray::SizeFor(length_) : 0;
   int size = JSArray::kSize + elements_size;
 
   // Load boilerplate object into ecx and check if we need to create a
   // boilerplate.
   Label slow_case;
   __ mov(ecx, Operand(esp, 3 * kPointerSize));
   __ mov(eax, Operand(esp, 2 * kPointerSize));
   ASSERT((kPointerSize == 4) && (kSmiTagSize == 1) && (kSmiTag == 0));
   __ mov(ecx, FieldOperand(ecx, eax, times_2, FixedArray::kHeaderSize));
@@ skipping 3172 matching lines @@
 
   // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
   // tagged as a small integer.
   __ bind(&runtime);
   __ TailCallRuntime(ExternalReference(Runtime::kStringCompare), 2, 1);
 }
 
 #undef __
 
 } }  // namespace v8::internal