Implement tracking and optimizations of packed arrays.

src/mips/ic-mips.cc

Index: src/mips/ic-mips.cc
diff --git a/src/mips/ic-mips.cc b/src/mips/ic-mips.cc
index 2c4da1a886455d6edd64004ed3c18d18c111bfdc..4017b54af981c87945c7758cd255483f9fca8de8 100644
--- a/src/mips/ic-mips.cc
+++ b/src/mips/ic-mips.cc
@@ -1347,8 +1347,7 @@ void KeyedStoreIC::GenerateGeneric(MacroAssembler* masm,
   __ LoadRoot(at, Heap::kHeapNumberMapRootIndex);
   __ Branch(&non_double_value, ne, t0, Operand(at));
 
-  // Value is a double. Transition FAST_SMI_ONLY_ELEMENTS ->
-  // FAST_DOUBLE_ELEMENTS and complete the store.
+  // Value is a double. Transition Smi -> Double and complete the store.
   __ LoadTransitionedArrayMapConditional(FAST_SMI_ONLY_ELEMENTS,
                                          FAST_DOUBLE_ELEMENTS,
                                          receiver_map,
@@ -1360,21 +1359,21 @@ void KeyedStoreIC::GenerateGeneric(MacroAssembler* masm,
   __ jmp(&fast_double_without_map_check);
 
   __ bind(&non_double_value);
-  // Value is not a double, FAST_SMI_ONLY_ELEMENTS -> FAST_ELEMENTS
+  // Value is not a double, Smi -> Object elements
   __ LoadTransitionedArrayMapConditional(FAST_SMI_ONLY_ELEMENTS,
                                          FAST_ELEMENTS,
                                          receiver_map,
                                          t0,
                                          &slow);
   ASSERT(receiver_map.is(a3));  // Transition code expects map in a3
-  ElementsTransitionGenerator::GenerateSmiOnlyToObject(masm);
+  ElementsTransitionGenerator::GenerateMapChangeElementTransition(masm);
   __ lw(elements, FieldMemOperand(receiver, JSObject::kElementsOffset));
   __ jmp(&finish_object_store);
 
   __ bind(&transition_double_elements);
-  // Elements are FAST_DOUBLE_ELEMENTS, but value is an Object that's not a
-  // HeapNumber. Make sure that the receiver is a Array with FAST_ELEMENTS and
-  // transition array from FAST_DOUBLE_ELEMENTS to FAST_ELEMENTS
+  // Elements are double, but value is an Object that's not a HeapNumber. Make
+  // sure that the receiver is a Array with Object elements and transition array
+  // from double elements to Object elements.
   __ LoadTransitionedArrayMapConditional(FAST_DOUBLE_ELEMENTS,
                                          FAST_ELEMENTS,
                                          receiver_map,