diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index c240869014..a2d1388d40 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -379,8 +379,7 @@ static Handle<JSFunction> InstallFunction(Handle<JSObject> target,
   } else {
     attributes = DONT_ENUM;
   }
-  JSObject::SetOwnPropertyIgnoreAttributes(
-      target, internalized_name, function, attributes).Check();
+  JSObject::AddProperty(target, internalized_name, function, attributes);
   if (target->IsJSGlobalObject()) {
     function->shared()->set_instance_class_name(*internalized_name);
   }
@@ -889,9 +888,8 @@ void Genesis::InitializeGlobal(Handle<GlobalObject> inner_global,
   Heap* heap = isolate->heap();
 
   Handle<String> object_name = factory->Object_string();
-  JSObject::SetOwnPropertyIgnoreAttributes(
-      inner_global, object_name,
-      isolate->object_function(), DONT_ENUM).Check();
+  JSObject::AddProperty(
+      inner_global, object_name, isolate->object_function(), DONT_ENUM);
 
   Handle<JSObject> global(native_context()->global_object());
 
@@ -1090,8 +1088,7 @@ void Genesis::InitializeGlobal(Handle<GlobalObject> inner_global,
     cons->SetInstanceClassName(*name);
     Handle<JSObject> json_object = factory->NewJSObject(cons, TENURED);
     ASSERT(json_object->IsJSObject());
-    JSObject::SetOwnPropertyIgnoreAttributes(
-        global, name, json_object, DONT_ENUM).Check();
+    JSObject::AddProperty(global, name, json_object, DONT_ENUM);
     native_context()->set_json_object(*json_object);
   }
 
@@ -1156,14 +1153,14 @@ void Genesis::InitializeGlobal(Handle<GlobalObject> inner_global,
     native_context()->set_sloppy_arguments_boilerplate(*result);
     // Note: length must be added as the first property and
     //       callee must be added as the second property.
-    JSObject::SetOwnPropertyIgnoreAttributes(
+    JSObject::AddProperty(
         result, factory->length_string(),
         factory->undefined_value(), DONT_ENUM,
-        Object::FORCE_TAGGED, FORCE_FIELD).Check();
-    JSObject::SetOwnPropertyIgnoreAttributes(
+        Object::FORCE_TAGGED, FORCE_FIELD);
+    JSObject::AddProperty(
         result, factory->callee_string(),
         factory->undefined_value(), DONT_ENUM,
-        Object::FORCE_TAGGED, FORCE_FIELD).Check();
+        Object::FORCE_TAGGED, FORCE_FIELD);
 
 #ifdef DEBUG
     LookupResult lookup(isolate);
@@ -1262,11 +1259,6 @@ void Genesis::InitializeGlobal(Handle<GlobalObject> inner_global,
     Handle<JSObject> result = factory->NewJSObjectFromMap(map);
     native_context()->set_strict_arguments_boilerplate(*result);
 
-    // Add length property only for strict mode boilerplate.
-    JSObject::SetOwnPropertyIgnoreAttributes(
-        result, factory->length_string(),
-        factory->undefined_value(), DONT_ENUM).Check();
-
 #ifdef DEBUG
     LookupResult lookup(isolate);
     result->LookupOwn(factory->length_string(), &lookup);
@@ -1274,6 +1266,10 @@ void Genesis::InitializeGlobal(Handle<GlobalObject> inner_global,
     ASSERT(lookup.GetFieldIndex().property_index() ==
            Heap::kArgumentsLengthIndex);
 
+    Handle<Object> length_value = Object::GetProperty(
+        result, factory->length_string()).ToHandleChecked();
+    ASSERT_EQ(heap->undefined_value(), *length_value);
+
     ASSERT(result->map()->inobject_properties() > Heap::kArgumentsLengthIndex);
 
     // Check the state of the object.
@@ -1736,12 +1732,10 @@ bool Genesis::InstallNatives() {
   Handle<String> global_string =
       factory()->InternalizeOneByteString(STATIC_ASCII_VECTOR("global"));
   Handle<Object> global_obj(native_context()->global_object(), isolate());
-  JSObject::SetOwnPropertyIgnoreAttributes(
-      builtins, global_string, global_obj, attributes).Check();
+  JSObject::AddProperty(builtins, global_string, global_obj, attributes);
   Handle<String> builtins_string =
       factory()->InternalizeOneByteString(STATIC_ASCII_VECTOR("builtins"));
-  JSObject::SetOwnPropertyIgnoreAttributes(
-      builtins, builtins_string, builtins, attributes).Check();
+  JSObject::AddProperty(builtins, builtins_string, builtins, attributes);
 
   // Set up the reference from the global object to the builtins object.
   JSGlobalObject::cast(native_context()->global_object())->
@@ -2454,16 +2448,14 @@ void Genesis::TransferNamedProperties(Handle<JSObject> from,
           ASSERT(!descs->GetDetails(i).representation().IsDouble());
           Handle<Object> value = Handle<Object>(from->RawFastPropertyAt(index),
                                                 isolate());
-          JSObject::SetOwnPropertyIgnoreAttributes(
-              to, key, value, details.attributes()).Check();
+          JSObject::AddProperty(to, key, value, details.attributes());
           break;
         }
         case CONSTANT: {
           HandleScope inner(isolate());
           Handle<Name> key = Handle<Name>(descs->GetKey(i));
           Handle<Object> constant(descs->GetConstant(i), isolate());
-          JSObject::SetOwnPropertyIgnoreAttributes(
-              to, key, constant, details.attributes()).Check();
+          JSObject::AddProperty(to, key, constant, details.attributes());
           break;
         }
         case CALLBACKS: {
@@ -2513,8 +2505,7 @@ void Genesis::TransferNamedProperties(Handle<JSObject> from,
                                  isolate());
         }
         PropertyDetails details = properties->DetailsAt(i);
-        JSObject::SetOwnPropertyIgnoreAttributes(
-            to, key, value, details.attributes()).Check();
+        JSObject::AddProperty(to, key, value, details.attributes());
       }
     }
   }
diff --git a/src/factory.cc b/src/factory.cc
index 29e396b8db..0f56fca9a1 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -1333,10 +1333,7 @@ Handle<JSObject> Factory::NewFunctionPrototype(Handle<JSFunction> function) {
   Handle<JSObject> prototype = NewJSObjectFromMap(new_map);
 
   if (!function->shared()->is_generator()) {
-    JSObject::SetOwnPropertyIgnoreAttributes(prototype,
-                                             constructor_string(),
-                                             function,
-                                             DONT_ENUM).Assert();
+    JSObject::AddProperty(prototype, constructor_string(), function, DONT_ENUM);
   }
 
   return prototype;
@@ -2159,11 +2156,19 @@ Handle<JSFunction> Factory::CreateApiFunction(
     return result;
   }
 
-  JSObject::SetOwnPropertyIgnoreAttributes(
-      handle(JSObject::cast(result->prototype())),
-      constructor_string(),
-      result,
-      DONT_ENUM).Assert();
+  if (prototype->IsTheHole()) {
+#ifdef DEBUG
+    LookupIterator it(handle(JSObject::cast(result->prototype())),
+                      constructor_string(),
+                      LookupIterator::CHECK_OWN_REAL);
+    MaybeHandle<Object> maybe_prop = Object::GetProperty(&it);
+    ASSERT(it.IsFound());
+    ASSERT(maybe_prop.ToHandleChecked().is_identical_to(result));
+#endif
+  } else {
+    JSObject::AddProperty(handle(JSObject::cast(result->prototype())),
+                          constructor_string(), result, DONT_ENUM);
+  }
 
   // Down from here is only valid for API functions that can be used as a
   // constructor (don't set the "remove prototype" flag).
diff --git a/src/isolate.cc b/src/isolate.cc
index 10b1db1e73..05f87922f1 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -494,31 +494,29 @@ Handle<JSArray> Isolate::CaptureCurrentStackTrace(
             // tag.
             column_offset += script->column_offset()->value();
           }
-          JSObject::SetOwnPropertyIgnoreAttributes(
+          JSObject::AddProperty(
               stack_frame, column_key,
-              Handle<Smi>(Smi::FromInt(column_offset + 1), this), NONE).Check();
+              handle(Smi::FromInt(column_offset + 1), this), NONE);
         }
-       JSObject::SetOwnPropertyIgnoreAttributes(
+       JSObject::AddProperty(
             stack_frame, line_key,
-            Handle<Smi>(Smi::FromInt(line_number + 1), this), NONE).Check();
+            handle(Smi::FromInt(line_number + 1), this), NONE);
       }
 
       if (options & StackTrace::kScriptId) {
-        Handle<Smi> script_id(script->id(), this);
-        JSObject::SetOwnPropertyIgnoreAttributes(
-            stack_frame, script_id_key, script_id, NONE).Check();
+        JSObject::AddProperty(
+            stack_frame, script_id_key, handle(script->id(), this), NONE);
       }
 
       if (options & StackTrace::kScriptName) {
-        Handle<Object> script_name(script->name(), this);
-        JSObject::SetOwnPropertyIgnoreAttributes(
-            stack_frame, script_name_key, script_name, NONE).Check();
+        JSObject::AddProperty(
+            stack_frame, script_name_key, handle(script->name(), this), NONE);
       }
 
       if (options & StackTrace::kScriptNameOrSourceURL) {
         Handle<Object> result = Script::GetNameOrSourceURL(script);
-        JSObject::SetOwnPropertyIgnoreAttributes(
-            stack_frame, script_name_or_source_url_key, result, NONE).Check();
+        JSObject::AddProperty(
+            stack_frame, script_name_or_source_url_key, result, NONE);
       }
 
       if (options & StackTrace::kFunctionName) {
@@ -526,23 +524,21 @@ Handle<JSArray> Isolate::CaptureCurrentStackTrace(
         if (!fun_name->BooleanValue()) {
           fun_name = Handle<Object>(fun->shared()->inferred_name(), this);
         }
-        JSObject::SetOwnPropertyIgnoreAttributes(
-            stack_frame, function_key, fun_name, NONE).Check();
+        JSObject::AddProperty(stack_frame, function_key, fun_name, NONE);
       }
 
       if (options & StackTrace::kIsEval) {
         Handle<Object> is_eval =
             script->compilation_type() == Script::COMPILATION_TYPE_EVAL ?
                 factory()->true_value() : factory()->false_value();
-        JSObject::SetOwnPropertyIgnoreAttributes(
-            stack_frame, eval_key, is_eval, NONE).Check();
+        JSObject::AddProperty(stack_frame, eval_key, is_eval, NONE);
       }
 
       if (options & StackTrace::kIsConstructor) {
         Handle<Object> is_constructor = (frames[i].is_constructor()) ?
             factory()->true_value() : factory()->false_value();
-        JSObject::SetOwnPropertyIgnoreAttributes(
-            stack_frame, constructor_key, is_constructor, NONE).Check();
+        JSObject::AddProperty(
+            stack_frame, constructor_key, is_constructor, NONE);
       }
 
       FixedArray::cast(stack_trace->elements())->set(frames_seen, *stack_frame);
diff --git a/src/objects.cc b/src/objects.cc
index c0dde8dbbd..176828ec9e 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -1873,7 +1873,7 @@ void JSObject::AddSlowProperty(Handle<JSObject> object,
 }
 
 
-MaybeHandle<Object> JSObject::AddProperty(
+MaybeHandle<Object> JSObject::AddPropertyInternal(
     Handle<JSObject> object,
     Handle<Name> name,
     Handle<Object> value,
@@ -3926,10 +3926,10 @@ MaybeHandle<Object> JSObject::SetPropertyUsingTransition(
   PropertyDetails details = descriptors->GetDetails(descriptor);
 
   if (details.type() == CALLBACKS || attributes != details.attributes()) {
-    // AddProperty will either normalize the object, or create a new fast copy
-    // of the map. If we get a fast copy of the map, all field representations
-    // will be tagged since the transition is omitted.
-    return JSObject::AddProperty(
+    // AddPropertyInternal will either normalize the object, or create a new
+    // fast copy of the map. If we get a fast copy of the map, all field
+    // representations will be tagged since the transition is omitted.
+    return JSObject::AddPropertyInternal(
         object, name, value, attributes, SLOPPY,
         JSReceiver::CERTAINLY_NOT_STORE_FROM_KEYED,
         JSReceiver::OMIT_EXTENSIBILITY_CHECK,
@@ -4093,7 +4093,7 @@ MaybeHandle<Object> JSObject::SetPropertyForResult(
 
   if (!lookup->IsFound()) {
     // Neither properties nor transitions found.
-    return AddProperty(
+    return AddPropertyInternal(
         object, name, value, attributes, strict_mode, store_mode);
   }
 
@@ -4173,6 +4173,28 @@ MaybeHandle<Object> JSObject::SetPropertyForResult(
 }
 
 
+void JSObject::AddProperty(
+    Handle<JSObject> object,
+    Handle<Name> name,
+    Handle<Object> value,
+    PropertyAttributes attributes,
+    ValueType value_type,
+    StoreMode store_mode) {
+#ifdef DEBUG
+  uint32_t index;
+  ASSERT(!object->IsJSProxy());
+  ASSERT(!name->AsArrayIndex(&index));
+  LookupIterator it(object, name, LookupIterator::CHECK_OWN_REAL);
+  GetPropertyAttributes(&it);
+  ASSERT(!it.IsFound());
+  ASSERT(object->map()->is_extensible());
+#endif
+  SetOwnPropertyIgnoreAttributes(
+      object, name, value, attributes, value_type, store_mode,
+      OMIT_EXTENSIBILITY_CHECK).Check();
+}
+
+
 // Set a real own property, even if it is READ_ONLY.  If the property is not
 // present, add it with attributes NONE.  This code is an exact clone of
 // SetProperty, with the check for IsReadOnly and the check for a
@@ -4228,7 +4250,7 @@ MaybeHandle<Object> JSObject::SetOwnPropertyIgnoreAttributes(
     TransitionFlag flag = lookup.IsFound()
         ? OMIT_TRANSITION : INSERT_TRANSITION;
     // Neither properties nor transitions found.
-    return AddProperty(object, name, value, attributes, SLOPPY,
+    return AddPropertyInternal(object, name, value, attributes, SLOPPY,
         store_from_keyed, extensibility_check, value_type, mode, flag);
   }
 
@@ -5154,13 +5176,8 @@ Handle<ObjectHashTable> JSObject::GetOrCreateHiddenPropertiesHashtable(
   }
 
   JSObject::SetOwnPropertyIgnoreAttributes(
-      object,
-      isolate->factory()->hidden_string(),
-      hashtable,
-      DONT_ENUM,
-      OPTIMAL_REPRESENTATION,
-      ALLOW_AS_CONSTANT,
-      OMIT_EXTENSIBILITY_CHECK).Assert();
+      object, isolate->factory()->hidden_string(),
+      hashtable, DONT_ENUM).Assert();
 
   return hashtable;
 }
diff --git a/src/objects.h b/src/objects.h
index ef3cd34a9a..764cdd909f 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2153,6 +2153,13 @@ class JSObject: public JSReceiver {
       StoreFromKeyed store_mode = MAY_BE_STORE_FROM_KEYED,
       ExecutableAccessorInfoHandling handling = DEFAULT_HANDLING);
 
+  static void AddProperty(Handle<JSObject> object,
+                          Handle<Name> key,
+                          Handle<Object> value,
+                          PropertyAttributes attributes,
+                          ValueType value_type = OPTIMAL_REPRESENTATION,
+                          StoreMode mode = ALLOW_AS_CONSTANT);
+
   // Extend the receiver with a single fast property appeared first in the
   // passed map. This also extends the property backing store if necessary.
   static void AllocateStorageForMap(Handle<JSObject> object, Handle<Map> map);
@@ -2750,7 +2757,7 @@ class JSObject: public JSReceiver {
       StrictMode strict_mode);
 
   // Add a property to an object.
-  MUST_USE_RESULT static MaybeHandle<Object> AddProperty(
+  MUST_USE_RESULT static MaybeHandle<Object> AddPropertyInternal(
       Handle<JSObject> object,
       Handle<Name> name,
       Handle<Object> value,
diff --git a/src/runtime.cc b/src/runtime.cc
index 5efaaa13d4..888f665d21 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -303,8 +303,7 @@ MUST_USE_RESULT static MaybeHandle<Object> CreateObjectLiteralBoilerplate(
       const char* str = DoubleToCString(num, buffer);
       Handle<String> name = isolate->factory()->NewStringFromAsciiChecked(str);
       maybe_result = JSObject::SetOwnPropertyIgnoreAttributes(
-          boilerplate, name, value, NONE,
-          value_type, mode);
+          boilerplate, name, value, NONE, value_type, mode);
     }
     // If setting the property on the boilerplate throws an
     // exception, the exception is converted to an empty handle in
@@ -2396,10 +2395,7 @@ RUNTIME_FUNCTION(Runtime_InitializeConstGlobal) {
   if (!lookup.IsFound()) {
     HandleScope handle_scope(isolate);
     Handle<GlobalObject> global(isolate->context()->global_object());
-    RETURN_FAILURE_ON_EXCEPTION(
-        isolate,
-        JSObject::SetOwnPropertyIgnoreAttributes(global, name, value,
-                                                 attributes));
+    JSObject::AddProperty(global, name, value, attributes);
     return *value;
   }
 
@@ -8133,8 +8129,8 @@ RUNTIME_FUNCTION(Runtime_FunctionBindArguments) {
       static_cast<PropertyAttributes>(DONT_DELETE | DONT_ENUM | READ_ONLY);
   RETURN_FAILURE_ON_EXCEPTION(
       isolate,
-      JSObject::SetOwnPropertyIgnoreAttributes(bound_function, length_string,
-                                               new_length, attr));
+      JSObject::SetOwnPropertyIgnoreAttributes(
+          bound_function, length_string, new_length, attr));
   return *bound_function;
 }
 
@@ -13809,18 +13805,10 @@ RUNTIME_FUNCTION(Runtime_GetLanguageTagVariants) {
     }
 
     Handle<JSObject> result = factory->NewJSObject(isolate->object_function());
-    RETURN_FAILURE_ON_EXCEPTION(isolate,
-        JSObject::SetOwnPropertyIgnoreAttributes(
-            result,
-            maximized,
-            factory->NewStringFromAsciiChecked(base_max_locale),
-            NONE));
-    RETURN_FAILURE_ON_EXCEPTION(isolate,
-        JSObject::SetOwnPropertyIgnoreAttributes(
-            result,
-            base,
-            factory->NewStringFromAsciiChecked(base_locale),
-            NONE));
+    Handle<String> value = factory->NewStringFromAsciiChecked(base_max_locale);
+    JSObject::AddProperty(result, maximized, value, NONE);
+    value = factory->NewStringFromAsciiChecked(base_locale);
+    JSObject::AddProperty(result, base, value, NONE);
     output->set(i, *result);
   }
 
@@ -13937,12 +13925,10 @@ RUNTIME_FUNCTION(Runtime_CreateDateTimeFormat) {
 
   local_object->SetInternalField(0, reinterpret_cast<Smi*>(date_format));
 
-  RETURN_FAILURE_ON_EXCEPTION(isolate,
-      JSObject::SetOwnPropertyIgnoreAttributes(
-          local_object,
-          isolate->factory()->NewStringFromStaticAscii("dateFormat"),
-          isolate->factory()->NewStringFromStaticAscii("valid"),
-          NONE));
+  Factory* factory = isolate->factory();
+  Handle<String> key = factory->NewStringFromStaticAscii("dateFormat");
+  Handle<String> value = factory->NewStringFromStaticAscii("valid");
+  JSObject::AddProperty(local_object, key, value, NONE);
 
   // Make object handle weak so we can delete the data format once GC kicks in.
   Handle<Object> wrapper = isolate->global_handles()->Create(*local_object);
@@ -14036,12 +14022,10 @@ RUNTIME_FUNCTION(Runtime_CreateNumberFormat) {
 
   local_object->SetInternalField(0, reinterpret_cast<Smi*>(number_format));
 
-  RETURN_FAILURE_ON_EXCEPTION(isolate,
-      JSObject::SetOwnPropertyIgnoreAttributes(
-          local_object,
-          isolate->factory()->NewStringFromStaticAscii("numberFormat"),
-          isolate->factory()->NewStringFromStaticAscii("valid"),
-          NONE));
+  Factory* factory = isolate->factory();
+  Handle<String> key = factory->NewStringFromStaticAscii("numberFormat");
+  Handle<String> value = factory->NewStringFromStaticAscii("valid");
+  JSObject::AddProperty(local_object, key, value, NONE);
 
   Handle<Object> wrapper = isolate->global_handles()->Create(*local_object);
   GlobalHandles::MakeWeak(wrapper.location(),
@@ -14144,12 +14128,10 @@ RUNTIME_FUNCTION(Runtime_CreateCollator) {
 
   local_object->SetInternalField(0, reinterpret_cast<Smi*>(collator));
 
-  RETURN_FAILURE_ON_EXCEPTION(isolate,
-      JSObject::SetOwnPropertyIgnoreAttributes(
-          local_object,
-          isolate->factory()->NewStringFromStaticAscii("collator"),
-          isolate->factory()->NewStringFromStaticAscii("valid"),
-          NONE));
+  Factory* factory = isolate->factory();
+  Handle<String> key = factory->NewStringFromStaticAscii("collator");
+  Handle<String> value = factory->NewStringFromStaticAscii("valid");
+  JSObject::AddProperty(local_object, key, value, NONE);
 
   Handle<Object> wrapper = isolate->global_handles()->Create(*local_object);
   GlobalHandles::MakeWeak(wrapper.location(),
@@ -14250,12 +14232,10 @@ RUNTIME_FUNCTION(Runtime_CreateBreakIterator) {
   // Make sure that the pointer to adopted text is NULL.
   local_object->SetInternalField(1, reinterpret_cast<Smi*>(NULL));
 
-  RETURN_FAILURE_ON_EXCEPTION(isolate,
-      JSObject::SetOwnPropertyIgnoreAttributes(
-          local_object,
-          isolate->factory()->NewStringFromStaticAscii("breakIterator"),
-          isolate->factory()->NewStringFromStaticAscii("valid"),
-          NONE));
+  Factory* factory = isolate->factory();
+  Handle<String> key = factory->NewStringFromStaticAscii("breakIterator");
+  Handle<String> value = factory->NewStringFromStaticAscii("valid");
+  JSObject::AddProperty(local_object, key, value, NONE);
 
   // Make object handle weak so we can delete the break iterator once GC kicks
   // in.