[runtime][ic] Constant field tracking support.

src/ic/handler-configuration-inl.h

 // Copyright 2016 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.
 
 #ifndef V8_IC_HANDLER_CONFIGURATION_INL_H_
 #define V8_IC_HANDLER_CONFIGURATION_INL_H_
 
 #include "src/ic/handler-configuration.h"
 
 #include "src/field-index-inl.h"
@@ skipping 85 matching lines @@
       break;
     case Representation::kTagged:
       field_rep = StoreHandler::kTagged;
       break;
     default:
       UNREACHABLE();
       return Handle<Object>::null();
   }
   int value_index = DescriptorArray::ToValueIndex(descriptor);
 
-  DCHECK(kind == kStoreField || kind == kTransitionToField);
+  DCHECK(kind == kStoreField || kind == kTransitionToField ||
+         (kind == kStoreConstField && FLAG_track_constant_fields));
   DCHECK_IMPLIES(extend_storage, kind == kTransitionToField);
   DCHECK_IMPLIES(field_index.is_inobject(), !extend_storage);
 
   int config = StoreHandler::KindBits::encode(kind) |
                StoreHandler::ExtendStorageBits::encode(extend_storage) |
                StoreHandler::IsInobjectBits::encode(field_index.is_inobject()) |
                StoreHandler::FieldRepresentationBits::encode(field_rep) |
                StoreHandler::DescriptorValueIndexBits::encode(value_index) |
                StoreHandler::FieldOffsetBits::encode(field_index.offset());
   return handle(Smi::FromInt(config), isolate);
 }
 
 Handle<Object> StoreHandler::StoreField(Isolate* isolate, int descriptor,
                                         FieldIndex field_index,
+                                        PropertyConstness constness,
                                         Representation representation) {
-  return StoreField(isolate, kStoreField, descriptor, field_index,
-                    representation, false);
+  DCHECK_IMPLIES(!FLAG_track_constant_fields, constness == kMutable);
+  Kind kind = constness == kMutable ? kStoreField : kStoreConstField;
+  return StoreField(isolate, kind, descriptor, field_index, representation,
+                    false);
 }
 
 Handle<Object> StoreHandler::TransitionToField(Isolate* isolate, int descriptor,
                                                FieldIndex field_index,
                                                Representation representation,
                                                bool extend_storage) {
   return StoreField(isolate, kTransitionToField, descriptor, field_index,
                     representation, extend_storage);
 }
 
 Handle<Object> StoreHandler::TransitionToConstant(Isolate* isolate,
                                                   int descriptor) {
+  DCHECK(!FLAG_track_constant_fields);
   int value_index = DescriptorArray::ToValueIndex(descriptor);
   int config =
       StoreHandler::KindBits::encode(StoreHandler::kTransitionToConstant) |
       StoreHandler::DescriptorValueIndexBits::encode(value_index);
   return handle(Smi::FromInt(config), isolate);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_IC_HANDLER_CONFIGURATION_INL_H_