Turn off tracking of fields for the roll.

src/hydrogen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 7200 matching lines @@
   return ast_context()->ReturnInstruction(instr, expr->id());
 }
 
 
 void HOptimizedGraphBuilder::HandlePolymorphicStoreNamedField(
     Assignment* expr,
     HValue* object,
     HValue* value,
     SmallMapList* types,
     Handle<String> name) {
-  // Use monomorphic store if property lookup results in the same field index
-  // and compatible representation for all maps. Requires special map check on
-  // the set of all handled maps.
-  if (types->length() <= kMaxStorePolymorphism) {
-    int previous_field_offset = 0;
-    bool previous_field_is_in_object = false;
-    Representation previous_representation = Representation::None();
-
-    Handle<Map> map;
-    LookupResult lookup(isolate());
-    int count;
-    for (count = 0; count < types->length(); ++count) {
-      map = types->at(count);
-      if (!ComputeLoadStoreField(map, name, &lookup, false) ||
-          lookup.IsTransition()) {
-        break;
-      }
-      Representation representation = lookup.representation();
-      int index = ComputeLoadStoreFieldIndex(map, &lookup);
-      bool is_in_object = index < 0;
-      int offset = index * kPointerSize;
-      if (index < 0) {
-        offset += map->instance_size();
-      } else {
-        offset += FixedArray::kHeaderSize;
-      }
-      if (count == 0) {
-        previous_field_offset = offset;
-        previous_field_is_in_object = is_in_object;
-        previous_representation = representation;
-      } else if (offset != previous_field_offset ||
-                 is_in_object != previous_field_is_in_object ||
-                 !representation.IsCompatibleForStore(
-                     previous_representation)) {
-        break;
-      }
-    }
-
-    if (types->length() == count) {
-      AddInstruction(new(zone()) HCheckNonSmi(object));
-      AddInstruction(HCheckMaps::New(object, types, zone()));
-      HInstruction* instr = BuildStoreNamedField(
-          object, name, value, map, &lookup);
-      AddInstruction(instr);
-      instr->set_position(expr->position());
-      // The HSimulate for the store should not see the stored value in
-      // effect contexts (it is not materialized at expr->id() in the
-      // unoptimized code).
-      if (instr->HasObservableSideEffects()) {
-        if (ast_context()->IsEffect()) {
-          AddSimulate(expr->id(), REMOVABLE_SIMULATE);
-        } else {
-          Push(value);
-          AddSimulate(expr->id(), REMOVABLE_SIMULATE);
-          Drop(1);
-        }
-      }
-      return ast_context()->ReturnValue(value);
-    }
-  }
-
   // TODO(ager): We should recognize when the prototype chains for different
   // maps are identical. In that case we can avoid repeatedly generating the
   // same prototype map checks.
   int count = 0;
   HBasicBlock* join = NULL;
   for (int i = 0; i < types->length() && count < kMaxStorePolymorphism; ++i) {
     Handle<Map> map = types->at(i);
     LookupResult lookup(isolate());
     if (ComputeLoadStoreField(map, name, &lookup, true)) {
       if (count == 0) {
@@ skipping 5073 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal