Map::TransitionElementsTo() extracted from JSObject::GetElementsTransitionMap().

src/ic.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #include "accessors.h"
 #include "api.h"
 #include "arguments.h"
 #include "codegen.h"
@@ skipping 1446 matching lines @@
   // and so the stubs can't be harvested for the object needed for a map check.
   if (target()->type() != Code::NORMAL) {
     TRACE_GENERIC_IC(isolate(), "KeyedIC", "non-NORMAL target type");
     return generic_stub();
   }
 
   Handle<Map> receiver_map(receiver->map(), isolate());
   MapHandleList target_receiver_maps;
   TargetMaps(&target_receiver_maps);
   if (target_receiver_maps.length() == 0) {
-    Handle<Map> monomorphic_map = ComputeTransitionedMap(receiver, store_mode);
+    Handle<Map> monomorphic_map =
+        ComputeTransitionedMap(receiver_map, store_mode);
     store_mode = GetNonTransitioningStoreMode(store_mode);
     return isolate()->stub_cache()->ComputeKeyedStoreElement(
         monomorphic_map, strict_mode(), store_mode);
   }
 
   // There are several special cases where an IC that is MONOMORPHIC can still
   // transition to a different GetNonTransitioningStoreMode IC that handles a
   // superset of the original IC. Handle those here if the receiver map hasn't
   // changed or it has transitioned to a more general kind.
   KeyedAccessStoreMode old_store_mode =
       KeyedStoreIC::GetKeyedAccessStoreMode(target()->extra_ic_state());
   Handle<Map> previous_receiver_map = target_receiver_maps.at(0);
   if (state() == MONOMORPHIC) {
     Handle<Map> transitioned_receiver_map = receiver_map;
     if (IsTransitionStoreMode(store_mode)) {
-      transitioned_receiver_map = ComputeTransitionedMap(receiver, store_mode);
+      transitioned_receiver_map =
+          ComputeTransitionedMap(receiver_map, store_mode);
     }
     if ((receiver_map.is_identical_to(previous_receiver_map) &&
          IsTransitionStoreMode(store_mode)) ||
         IsTransitionOfMonomorphicTarget(*previous_receiver_map,
                                         *transitioned_receiver_map)) {
       // If the "old" and "new" maps are in the same elements map family, or
       // if they at least come from the same origin for a transitioning store,
       // stay MONOMORPHIC and use the map for the most generic ElementsKind.
       store_mode = GetNonTransitioningStoreMode(store_mode);
       return isolate()->stub_cache()->ComputeKeyedStoreElement(
@@ skipping 11 matching lines @@
     }
   }
 
   ASSERT(state() != GENERIC);
 
   bool map_added =
       AddOneReceiverMapIfMissing(&target_receiver_maps, receiver_map);
 
   if (IsTransitionStoreMode(store_mode)) {
     Handle<Map> transitioned_receiver_map =
-        ComputeTransitionedMap(receiver, store_mode);
+        ComputeTransitionedMap(receiver_map, store_mode);
     map_added |= AddOneReceiverMapIfMissing(&target_receiver_maps,
                                             transitioned_receiver_map);
   }
 
   if (!map_added) {
     // If the miss wasn't due to an unseen map, a polymorphic stub
     // won't help, use the generic stub.
     TRACE_GENERIC_IC(isolate(), "KeyedIC", "same map added twice");
     return generic_stub();
   }
@@ skipping 35 matching lines @@
       return generic_stub();
     }
   }
 
   return isolate()->stub_cache()->ComputeStoreElementPolymorphic(
       &target_receiver_maps, store_mode, strict_mode());
 }
 
 
 Handle<Map> KeyedStoreIC::ComputeTransitionedMap(
-    Handle<JSObject> receiver,
+    Handle<Map> map,
     KeyedAccessStoreMode store_mode) {
   switch (store_mode) {
     case STORE_TRANSITION_SMI_TO_OBJECT:
     case STORE_TRANSITION_DOUBLE_TO_OBJECT:
     case STORE_AND_GROW_TRANSITION_SMI_TO_OBJECT:
     case STORE_AND_GROW_TRANSITION_DOUBLE_TO_OBJECT:
-      return JSObject::GetElementsTransitionMap(receiver, FAST_ELEMENTS);
+      return Map::TransitionElementsTo(map, FAST_ELEMENTS);
     case STORE_TRANSITION_SMI_TO_DOUBLE:
     case STORE_AND_GROW_TRANSITION_SMI_TO_DOUBLE:
-      return JSObject::GetElementsTransitionMap(receiver, FAST_DOUBLE_ELEMENTS);
+      return Map::TransitionElementsTo(map, FAST_DOUBLE_ELEMENTS);
     case STORE_TRANSITION_HOLEY_SMI_TO_OBJECT:
     case STORE_TRANSITION_HOLEY_DOUBLE_TO_OBJECT:
     case STORE_AND_GROW_TRANSITION_HOLEY_SMI_TO_OBJECT:
     case STORE_AND_GROW_TRANSITION_HOLEY_DOUBLE_TO_OBJECT:
-      return JSObject::GetElementsTransitionMap(receiver,
-                                                FAST_HOLEY_ELEMENTS);
+      return Map::TransitionElementsTo(map, FAST_HOLEY_ELEMENTS);
     case STORE_TRANSITION_HOLEY_SMI_TO_DOUBLE:
     case STORE_AND_GROW_TRANSITION_HOLEY_SMI_TO_DOUBLE:
-      return JSObject::GetElementsTransitionMap(receiver,
-                                                FAST_HOLEY_DOUBLE_ELEMENTS);
+      return Map::TransitionElementsTo(map, FAST_HOLEY_DOUBLE_ELEMENTS);
     case STORE_NO_TRANSITION_IGNORE_OUT_OF_BOUNDS:
-      ASSERT(receiver->map()->has_external_array_elements());
+      ASSERT(map->has_external_array_elements());
       // Fall through
     case STORE_NO_TRANSITION_HANDLE_COW:
     case STANDARD_STORE:
     case STORE_AND_GROW_NO_TRANSITION:
-      return Handle<Map>(receiver->map(), isolate());
+      return map;
   }
-  return Handle<Map>::null();
+  UNREACHABLE();
+  return MaybeHandle<Map>().ToHandleChecked();
 }
 
 
 bool IsOutOfBoundsAccess(Handle<JSObject> receiver,
                          int index) {
   if (receiver->IsJSArray()) {
     return JSArray::cast(*receiver)->length()->IsSmi() &&
         index >= Smi::cast(JSArray::cast(*receiver)->length())->value();
   }
   return index >= receiver->elements()->length();
@@ skipping 1296 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal