Remake of the load elimination fix made earlier (r18884).

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 3f178c0abac12075a204d05e98b7877321b7e97b..1e4c94b58bb5d2f05f8d2b68cf4530920083d50b 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -1968,18 +1968,12 @@ void JSObject::FastPropertyAtPut(int index, Object* value) {
 
 
 int JSObject::GetInObjectPropertyOffset(int index) {
-  // Adjust for the number of properties stored in the object.
-  index -= map()->inobject_properties();
-  ASSERT(index < 0);
-  return map()->instance_size() + (index * kPointerSize);
+  return map()->GetInObjectPropertyOffset(index);
 }
 
 
 Object* JSObject::InObjectPropertyAt(int index) {
-  // Adjust for the number of properties stored in the object.
-  index -= map()->inobject_properties();
-  ASSERT(index < 0);
-  int offset = map()->instance_size() + (index * kPointerSize);
+  int offset = GetInObjectPropertyOffset(index);
   return READ_FIELD(this, offset);
 }
 
@@ -1988,9 +1982,7 @@ Object* JSObject::InObjectPropertyAtPut(int index,
                                         Object* value,
                                         WriteBarrierMode mode) {
   // Adjust for the number of properties stored in the object.
-  index -= map()->inobject_properties();
-  ASSERT(index < 0);
-  int offset = map()->instance_size() + (index * kPointerSize);
+  int offset = GetInObjectPropertyOffset(index);
   WRITE_FIELD(this, offset, value);
   CONDITIONAL_WRITE_BARRIER(GetHeap(), this, offset, value, mode);
   return value;
@@ -3791,6 +3783,20 @@ int Map::pre_allocated_property_fields() {
 }
 
 
+int Map::GetInObjectPropertyOffset(int index) {
+  // Adjust for the number of properties stored in the object.
+  index -= inobject_properties();
+  ASSERT(index < 0);
+  return instance_size() + (index * kPointerSize);
+}
+
+
+int Map::GetInObjectPropertyIndex(int offset) {
+  ASSERT(offset >= 0);
+  return (offset - instance_size()) / kPointerSize + inobject_properties();
+}
+
+
 int HeapObject::SizeFromMap(Map* map) {
   int instance_size = map->instance_size();
   if (instance_size != kVariableSizeSentinel) return instance_size;