Copy-on-write arrays.

src/ia32/stub-cache-ia32.cc

 // Copyright 2006-2009 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 1348 matching lines @@
 
   CheckPrototypes(JSObject::cast(object), edx,
                   holder, ebx,
                   eax, edi, name, &miss);
 
   if (argc == 0) {
     // Noop, return the length.
     __ mov(eax, FieldOperand(edx, JSArray::kLengthOffset));
     __ ret((argc + 1) * kPointerSize);
   } else {
+    Label call_builtin;
+
     // Get the elements array of the object.
     __ mov(ebx, FieldOperand(edx, JSArray::kElementsOffset));
 
-    // Check that the elements are in fast mode (not dictionary).
+    // Check that the elements are in fast mode and writable.
     __ cmp(FieldOperand(ebx, HeapObject::kMapOffset),
            Immediate(Factory::fixed_array_map()));
-    __ j(not_equal, &miss);
+    __ j(not_equal, &call_builtin);
 
     if (argc == 1) {  // Otherwise fall through to call builtin.
-      Label call_builtin, exit, with_write_barrier, attempt_to_grow_elements;
+      Label exit, with_write_barrier, attempt_to_grow_elements;
 
       // Get the array's length into eax and calculate new length.
       __ mov(eax, FieldOperand(edx, JSArray::kLengthOffset));
       STATIC_ASSERT(kSmiTagSize == 1);
       STATIC_ASSERT(kSmiTag == 0);
       __ add(Operand(eax), Immediate(Smi::FromInt(argc)));
 
       // Get the element's length into ecx.
       __ mov(ecx, FieldOperand(ebx, FixedArray::kLengthOffset));
 
@@ skipping 60 matching lines @@
       // Restore receiver to edx as finish sequence assumes it's here.
       __ mov(edx, Operand(esp, (argc + 1) * kPointerSize));
 
       // Increment element's and array's sizes.
       __ add(FieldOperand(ebx, FixedArray::kLengthOffset),
              Immediate(Smi::FromInt(kAllocationDelta)));
       __ mov(FieldOperand(edx, JSArray::kLengthOffset), eax);
 
       // Elements are in new space, so write barrier is not required.
       __ ret((argc + 1) * kPointerSize);
-
-      __ bind(&call_builtin);
     }
 
+    __ bind(&call_builtin);
     __ TailCallExternalReference(ExternalReference(Builtins::c_ArrayPush),
                                  argc + 1,
                                  1);
   }
 
   __ bind(&miss);
   Object* obj = GenerateMissBranch();
   if (obj->IsFailure()) return obj;
 
   // Return the generated code.
@@ skipping 31 matching lines @@
   // Check that the receiver isn't a smi.
   __ test(edx, Immediate(kSmiTagMask));
   __ j(zero, &miss);
   CheckPrototypes(JSObject::cast(object), edx,
                   holder, ebx,
                   eax, edi, name, &miss);
 
   // Get the elements array of the object.
   __ mov(ebx, FieldOperand(edx, JSArray::kElementsOffset));
 
-  // Check that the elements are in fast mode (not dictionary).
+  // Check that the elements are in fast mode and writable.
   __ cmp(FieldOperand(ebx, HeapObject::kMapOffset),
          Immediate(Factory::fixed_array_map()));
-  __ j(not_equal, &miss);
+  __ j(not_equal, &call_builtin);
 
   // Get the array's length into ecx and calculate new length.
   __ mov(ecx, FieldOperand(edx, JSArray::kLengthOffset));
   __ sub(Operand(ecx), Immediate(Smi::FromInt(1)));
   __ j(negative, &return_undefined);
 
   // Get the last element.
   STATIC_ASSERT(kSmiTagSize == 1);
   STATIC_ASSERT(kSmiTag == 0);
   __ mov(eax, FieldOperand(ebx,
@@ skipping 1203 matching lines @@
   // Return the generated code.
   return GetCode();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32