Remove SmartMove, bringing Array methods further into spec compliance

src/array.js

Index: src/array.js
diff --git a/src/array.js b/src/array.js
index b6f3a89d698fee679b4ae1a6e9c5c2eb9d8da969..8579450ab48f236a387c7dace74e19680001c1e4 100644
--- a/src/array.js
+++ b/src/array.js
@@ -231,50 +231,6 @@ function SmartSlice(array, start_i, del_count, len, deleted_elements) {
 }
 
 
-// This function implements the optimized splice implementation that can use
-// special array operations to handle sparse arrays in a sensible fashion.
-function SmartMove(array, start_i, del_count, len, num_additional_args) {
-  // Move data to new array.
-  var new_array = new InternalArray(len - del_count + num_additional_args);
-  var indices = %GetArrayKeys(array, len);
-  if (IS_NUMBER(indices)) {
-    var limit = indices;
-    for (var i = 0; i < start_i && i < limit; ++i) {
-      var current = array[i];
-      if (!IS_UNDEFINED(current) || i in array) {
-        new_array[i] = current;
-      }
-    }
-    for (var i = start_i + del_count; i < limit; ++i) {
-      var current = array[i];
-      if (!IS_UNDEFINED(current) || i in array) {
-        new_array[i - del_count + num_additional_args] = current;
-      }
-    }
-  } else {
-    var length = indices.length;
-    for (var k = 0; k < length; ++k) {
-      var key = indices[k];
-      if (!IS_UNDEFINED(key)) {
-        if (key < start_i) {
-          var current = array[key];
-          if (!IS_UNDEFINED(current) || key in array) {
-            new_array[key] = current;
-          }
-        } else if (key >= start_i + del_count) {
-          var current = array[key];
-          if (!IS_UNDEFINED(current) || key in array) {
-            new_array[key - del_count + num_additional_args] = current;
-          }
-        }
-      }
-    }
-  }
-  // Move contents of new_array into this array
-  %MoveArrayContents(new_array, array);
-}
-
-
 // This is part of the old simple-minded splice.  We are using it either
 // because the receiver is not an array (so we have no choice) or because we
 // know we are not deleting or moving a lot of elements.
@@ -292,8 +248,9 @@ function SimpleSlice(array, start_i, del_count, len, deleted_elements) {
 }
 
 
-function SimpleMove(array, start_i, del_count, len, num_additional_args) {
-  if (num_additional_args !== del_count) {
+function SimpleMove(array, start_i, del_count, len, num_additional_args,
+    force) {
+  if (num_additional_args !== del_count || force) {
     // Move the existing elements after the elements to be deleted
     // to the right position in the resulting array.
     if (num_additional_args > del_count) {
@@ -604,11 +561,7 @@ function ArrayShift() {
 
   var first = array[0];
 
-  if (IS_ARRAY(array)) {
-    SmartMove(array, 0, 1, len, 0);
-  } else {
-    SimpleMove(array, 0, 1, len, 0);
-  }
+  SimpleMove(array, 0, 1, len, 0);
 
   array.length = len - 1;
 
@@ -644,14 +597,7 @@ function ArrayUnshift(arg1) {  // length == 1
   var array = TO_OBJECT_INLINE(this);
   var len = TO_UINT32(array.length);
   var num_arguments = %_ArgumentsLength();
-  var is_sealed = ObjectIsSealed(array);
-
-  if (IS_ARRAY(array) && !is_sealed && len > 0) {
-    SmartMove(array, 0, 0, len, num_arguments);
-  } else {
-    SimpleMove(array, 0, 0, len, num_arguments);
-  }
-
+  SimpleMove(array, 0, 0, len, num_arguments, true);
   for (var i = 0; i < num_arguments; i++) {
     array[i] = %_Arguments(i);
   }
@@ -806,15 +752,8 @@ function ArraySplice(start, delete_count) {
     // point, then include those in the estimate of changed elements.
     changed_elements += len - start_i - del_count;
   }
-  if (UseSparseVariant(array, len, IS_ARRAY(array), changed_elements)) {
-    %NormalizeElements(array);
-    %NormalizeElements(deleted_elements);
-    SmartSlice(array, start_i, del_count, len, deleted_elements);
-    SmartMove(array, start_i, del_count, len, num_elements_to_add);
-  } else {
-    SimpleSlice(array, start_i, del_count, len, deleted_elements);
-    SimpleMove(array, start_i, del_count, len, num_elements_to_add);
-  }
+  SimpleSlice(array, start_i, del_count, len, deleted_elements);
+  SimpleMove(array, start_i, del_count, len, num_elements_to_add);
 
   // Insert the arguments into the resulting array in
   // place of the deleted elements.