[runtime][ic] Constant field tracking support.

src/ic/accessor-assembler.cc

 // 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.
 
 #include "src/ic/accessor-assembler.h"
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/ic/handler-configuration.h"
 #include "src/ic/stub-cache.h"
@@ skipping 612 matching lines @@
   Node* handler_kind = DecodeWord<StoreHandler::KindBits>(handler_word);
   if (transition) {
     CSA_ASSERT(
         this,
         Word32Or(
             WordEqual(handler_kind,
                       IntPtrConstant(StoreHandler::kTransitionToField)),
             WordEqual(handler_kind,
                       IntPtrConstant(StoreHandler::kTransitionToConstant))));
   } else {
-    CSA_ASSERT(this, WordEqual(handler_kind,
-                               IntPtrConstant(StoreHandler::kStoreField)));
+    if (FLAG_track_constant_fields) {
+      CSA_ASSERT(
+          this,
+          Word32Or(WordEqual(handler_kind,
+                             IntPtrConstant(StoreHandler::kStoreField)),
+                   WordEqual(handler_kind,
+                             IntPtrConstant(StoreHandler::kStoreConstField))));
+    } else {
+      CSA_ASSERT(this, WordEqual(handler_kind,
+                                 IntPtrConstant(StoreHandler::kStoreField)));
+    }
   }
 #endif
 
   Node* field_representation =
       DecodeWord<StoreHandler::FieldRepresentationBits>(handler_word);
 
   Label if_smi_field(this), if_double_field(this), if_heap_object_field(this),
       if_tagged_field(this);
 
   GotoIf(WordEqual(field_representation, IntPtrConstant(StoreHandler::kTagged)),
@@ skipping 46 matching lines @@
   Node* prepared_value = PrepareValueForStore(
       handler_word, holder, representation, transition, value, miss);
 
   Label if_inobject(this), if_out_of_object(this);
   Branch(IsSetWord<StoreHandler::IsInobjectBits>(handler_word), &if_inobject,
          &if_out_of_object);
 
   Bind(&if_inobject);
   {
     StoreNamedField(handler_word, holder, true, representation, prepared_value,
-                    transition_to_field);
+                    transition_to_field, miss);
     if (transition_to_field) {
       StoreMap(holder, transition);
     }
     Return(value);
   }
 
   Bind(&if_out_of_object);
   {
     if (transition_to_field) {
       Label storage_extended(this);
       GotoUnless(IsSetWord<StoreHandler::ExtendStorageBits>(handler_word),
                  &storage_extended);
       Comment("[ Extend storage");
       ExtendPropertiesBackingStore(holder);
       Comment("] Extend storage");
       Goto(&storage_extended);
 
       Bind(&storage_extended);
     }
 
     StoreNamedField(handler_word, holder, false, representation, prepared_value,
-                    transition_to_field);
+                    transition_to_field, miss);
     if (transition_to_field) {
       StoreMap(holder, transition);
     }
     Return(value);
   }
 }
 
 Node* AccessorAssembler::PrepareValueForStore(Node* handler_word, Node* holder,
                                               Representation representation,
                                               Node* transition, Node* value,
                                               Label* bailout) {
   if (representation.IsDouble()) {
     value = TryTaggedToFloat64(value, bailout);
 
   } else if (representation.IsHeapObject()) {
     GotoIf(TaggedIsSmi(value), bailout);
+
+    Label done(this);
+    if (FLAG_track_constant_fields && !transition) {
+      // Skip field type check in favor of constant value check when storing
+      // to constant field.
+      GotoIf(WordEqual(DecodeWord<StoreHandler::KindBits>(handler_word),
+                       IntPtrConstant(StoreHandler::kStoreConstField)),
+             &done);
+    }
     Node* value_index_in_descriptor =
         DecodeWord<StoreHandler::DescriptorValueIndexBits>(handler_word);
     Node* descriptors =
         LoadMapDescriptors(transition ? transition : LoadMap(holder));
     Node* maybe_field_type =
         LoadFixedArrayElement(descriptors, value_index_in_descriptor);
 
-    Label done(this);
     GotoIf(TaggedIsSmi(maybe_field_type), &done);
     // Check that value type matches the field type.
     {
       Node* field_type = LoadWeakCellValue(maybe_field_type, bailout);
       Branch(WordEqual(LoadMap(value), field_type), &done, bailout);
     }
     Bind(&done);
 
   } else if (representation.IsSmi()) {
     GotoUnless(TaggedIsSmi(value), bailout);
@@ skipping 36 matching lines @@
   // the write barrier.
   CopyFixedArrayElements(kind, properties, new_properties, length,
                          SKIP_WRITE_BARRIER, mode);
 
   StoreObjectField(object, JSObject::kPropertiesOffset, new_properties);
 }
 
 void AccessorAssembler::StoreNamedField(Node* handler_word, Node* object,
                                         bool is_inobject,
                                         Representation representation,
-                                        Node* value, bool transition_to_field) {
+                                        Node* value, bool transition_to_field,
+                                        Label* bailout) {
   bool store_value_as_double = representation.IsDouble();
   Node* property_storage = object;
   if (!is_inobject) {
     property_storage = LoadProperties(object);
   }
 
   Node* offset = DecodeWord<StoreHandler::FieldOffsetBits>(handler_word);
   if (representation.IsDouble()) {
     if (!FLAG_unbox_double_fields || !is_inobject) {
       if (transition_to_field) {
         Node* heap_number = AllocateHeapNumberWithValue(value, MUTABLE);
         // Store the new mutable heap number into the object.
         value = heap_number;
         store_value_as_double = false;
       } else {
         // Load the heap number.
         property_storage = LoadObjectField(property_storage, offset);
         // Store the double value into it.
         offset = IntPtrConstant(HeapNumber::kValueOffset);
       }
     }
   }
 
+  // Do constant value check if necessary.
+  if (FLAG_track_constant_fields && !transition_to_field) {
+    Label done(this);
+    GotoUnless(WordEqual(DecodeWord<StoreHandler::KindBits>(handler_word),
+                         IntPtrConstant(StoreHandler::kStoreConstField)),
+               &done);
+    {
+      if (store_value_as_double) {
+        Node* current_value =
+            LoadObjectField(property_storage, offset, MachineType::Float64());
+        GotoUnless(Float64Equal(current_value, value), bailout);
+      } else {
+        Node* current_value = LoadObjectField(property_storage, offset);
+        GotoUnless(WordEqual(current_value, value), bailout);
+      }
+      Goto(&done);
+    }
+    Bind(&done);
+  }
+
+  // Do the store.
   if (store_value_as_double) {
     StoreObjectFieldNoWriteBarrier(property_storage, offset, value,
                                    MachineRepresentation::kFloat64);
   } else if (representation.IsSmi()) {
     StoreObjectFieldNoWriteBarrier(property_storage, offset, value);
   } else {
     StoreObjectField(property_storage, offset, value);
   }
 }
 
@@ skipping 1045 matching lines @@
   Node* slot = Parameter(Descriptor::kSlot);
   Node* context = Parameter(Descriptor::kContext);
   Node* vector = LoadTypeFeedbackVectorForStub();
 
   StoreICParameters p(context, receiver, name, value, slot, vector);
   KeyedStoreIC(&p, language_mode);
 }
 
 }  // namespace internal
 }  // namespace v8