[api] Default native data property setter to replace the setter if the property is writable.

src/accessors.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 "src/accessors.h"
 
 #include "src/api.h"
 #include "src/contexts.h"
 #include "src/deoptimizer.h"
 #include "src/execution.h"
@@ skipping 16 matching lines @@
     AccessorNameSetterCallback setter,
     PropertyAttributes attributes) {
   Factory* factory = isolate->factory();
   Handle<AccessorInfo> info = factory->NewAccessorInfo();
   info->set_property_attributes(attributes);
   info->set_all_can_read(false);
   info->set_all_can_write(false);
   info->set_is_special_data_property(true);
   info->set_name(*name);
   Handle<Object> get = v8::FromCData(isolate, getter);
+  if (setter == nullptr) setter = &ReconfigureToDataProperty;
   Handle<Object> set = v8::FromCData(isolate, setter);
   info->set_getter(*get);
   info->set_setter(*set);
   return info;
 }
 
 
 static V8_INLINE bool CheckForName(Handle<Name> name,
                                    Handle<String> property_name,
                                    int offset,
@@ skipping 71 matching lines @@
     case JS_DATA_VIEW_TYPE:
       return CheckForName(name, isolate->factory()->byte_length_string(),
                           JSDataView::kByteLengthOffset, object_offset) ||
              CheckForName(name, isolate->factory()->byte_offset_string(),
                           JSDataView::kByteOffsetOffset, object_offset);
     default:
       return false;
   }
 }
 
+MUST_USE_RESULT static MaybeHandle<Object> ReplaceAccessorWithDataProperty(
+    Isolate* isolate, Handle<JSObject> receiver, Handle<JSObject> holder,
+    Handle<Name> name, Handle<Object> value, bool observe) {
+  LookupIterator it(receiver, name, holder,
+                    LookupIterator::OWN_SKIP_INTERCEPTOR);
+  // Skip any access checks we might hit. This accessor should never hit in a
+  // situation where the caller does not have access.
+  if (it.state() == LookupIterator::ACCESS_CHECK) {
+    CHECK(it.HasAccess());
+    it.Next();
+  }
+  CHECK_EQ(LookupIterator::ACCESSOR, it.state());
+
+  Handle<Object> old_value;
+  bool is_observed = observe && receiver->map()->is_observed();
+  if (is_observed) {
+    MaybeHandle<Object> maybe_old =
+        Object::GetPropertyWithAccessor(&it, SLOPPY);
+    if (!maybe_old.ToHandle(&old_value)) return maybe_old;
+  }
+
+  it.ReconfigureDataProperty(value, it.property_attributes());
+
+  if (is_observed && !old_value->SameValue(*value)) {
+    return JSObject::EnqueueChangeRecord(receiver, "update", name, old_value);
+  }
+
+  return value;
+}
+
+void Accessors::ReconfigureToDataProperty(
+    v8::Local<v8::Name> key, v8::Local<v8::Value> val,
+    const v8::PropertyCallbackInfo<void>& info) {
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
+  HandleScope scope(isolate);
+  Handle<JSObject> receiver =
+      Handle<JSObject>::cast(Utils::OpenHandle(*info.This()));
+  Handle<JSObject> holder =
+      Handle<JSObject>::cast(Utils::OpenHandle(*info.Holder()));
+  Handle<Name> name = Utils::OpenHandle(*key);
+  Handle<Object> value = Utils::OpenHandle(*val);
+  MaybeHandle<Object> result = ReplaceAccessorWithDataProperty(
+      isolate, receiver, holder, name, value, false);
+  if (result.is_null()) isolate->OptionalRescheduleException(false);
+}
 
 //
 // Accessors::ArgumentsIterator
 //
 
 
 void Accessors::ArgumentsIteratorGetter(
     v8::Local<v8::Name> name, const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* result = isolate->native_context()->array_values_iterator();
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(result, isolate)));
 }
 
 
-void Accessors::ArgumentsIteratorSetter(
-    v8::Local<v8::Name> name, v8::Local<v8::Value> val,
-    const v8::PropertyCallbackInfo<void>& info) {
-  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
-  HandleScope scope(isolate);
-  Handle<JSObject> object_handle =
-      Handle<JSObject>::cast(Utils::OpenHandle(*info.This()));
-  Handle<Object> value_handle = Utils::OpenHandle(*val);
-  Handle<Name> name_handle = Utils::OpenHandle(*name);
-
-  if (JSObject::DefinePropertyOrElementIgnoreAttributes(
-          object_handle, name_handle, value_handle, NONE)
-          .is_null()) {
-    isolate->OptionalRescheduleException(false);
-  }
-}
-
-
 Handle<AccessorInfo> Accessors::ArgumentsIteratorInfo(
     Isolate* isolate, PropertyAttributes attributes) {
   Handle<Name> name = isolate->factory()->iterator_symbol();
-  return MakeAccessor(isolate, name, &ArgumentsIteratorGetter,
-                      &ArgumentsIteratorSetter, attributes);
+  return MakeAccessor(isolate, name, &ArgumentsIteratorGetter, nullptr,
+                      attributes);
 }
 
 
 //
 // Accessors::ArrayLength
 //
 
 
 void Accessors::ArrayLengthGetter(
     v8::Local<v8::Name> name,
@@ skipping 73 matching lines @@
   if (!value->IsString()) {
     // Not a string value. That means that we either got a String wrapper or
     // a Value with a String wrapper in its prototype chain.
     value = JSValue::cast(*Utils::OpenHandle(*info.Holder()))->value();
   }
   Object* result = Smi::FromInt(String::cast(value)->length());
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(result, isolate)));
 }
 
 
-void Accessors::StringLengthSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::StringLengthInfo(
       Isolate* isolate, PropertyAttributes attributes) {
-  return MakeAccessor(isolate,
-                      isolate->factory()->length_string(),
-                      &StringLengthGetter,
-                      &StringLengthSetter,
-                      attributes);
+  return MakeAccessor(isolate, isolate->factory()->length_string(),
+                      &StringLengthGetter, nullptr, attributes);
 }
 
 
 //
 // Accessors::ScriptColumnOffset
 //
 
 
 void Accessors::ScriptColumnOffsetGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   Object* res = Smi::FromInt(
       Script::cast(JSValue::cast(object)->value())->column_offset());
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(res, isolate)));
 }
 
 
-void Accessors::ScriptColumnOffsetSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptColumnOffsetInfo(
       Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(isolate->factory()->InternalizeOneByteString(
       STATIC_CHAR_VECTOR("column_offset")));
-  return MakeAccessor(isolate,
-                      name,
-                      &ScriptColumnOffsetGetter,
-                      &ScriptColumnOffsetSetter,
+  return MakeAccessor(isolate, name, &ScriptColumnOffsetGetter, nullptr,
                       attributes);
 }
 
 
 //
 // Accessors::ScriptId
 //
 
 
 void Accessors::ScriptIdGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   Object* id = Smi::FromInt(Script::cast(JSValue::cast(object)->value())->id());
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(id, isolate)));
 }
 
 
-void Accessors::ScriptIdSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptIdInfo(
       Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(
       isolate->factory()->InternalizeOneByteString(STATIC_CHAR_VECTOR("id")));
-  return MakeAccessor(isolate,
-                      name,
-                      &ScriptIdGetter,
-                      &ScriptIdSetter,
-                      attributes);
+  return MakeAccessor(isolate, name, &ScriptIdGetter, nullptr, attributes);
 }
 
 
 //
 // Accessors::ScriptName
 //
 
 
 void Accessors::ScriptNameGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   Object* source = Script::cast(JSValue::cast(object)->value())->name();
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(source, isolate)));
 }
 
 
-void Accessors::ScriptNameSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptNameInfo(
       Isolate* isolate, PropertyAttributes attributes) {
-  return MakeAccessor(isolate,
-                      isolate->factory()->name_string(),
-                      &ScriptNameGetter,
-                      &ScriptNameSetter,
-                      attributes);
+  return MakeAccessor(isolate, isolate->factory()->name_string(),
+                      &ScriptNameGetter, nullptr, attributes);
 }
 
 
 //
 // Accessors::ScriptSource
 //
 
 
 void Accessors::ScriptSourceGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   Object* source = Script::cast(JSValue::cast(object)->value())->source();
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(source, isolate)));
 }
 
 
-void Accessors::ScriptSourceSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptSourceInfo(
       Isolate* isolate, PropertyAttributes attributes) {
-  return MakeAccessor(isolate,
-                      isolate->factory()->source_string(),
-                      &ScriptSourceGetter,
-                      &ScriptSourceSetter,
-                      attributes);
+  return MakeAccessor(isolate, isolate->factory()->source_string(),
+                      &ScriptSourceGetter, nullptr, attributes);
 }
 
 
 //
 // Accessors::ScriptLineOffset
 //
 
 
 void Accessors::ScriptLineOffsetGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   Object* res =
       Smi::FromInt(Script::cast(JSValue::cast(object)->value())->line_offset());
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(res, isolate)));
 }
 
 
-void Accessors::ScriptLineOffsetSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptLineOffsetInfo(
       Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(isolate->factory()->InternalizeOneByteString(
       STATIC_CHAR_VECTOR("line_offset")));
-  return MakeAccessor(isolate,
-                      name,
-                      &ScriptLineOffsetGetter,
-                      &ScriptLineOffsetSetter,
+  return MakeAccessor(isolate, name, &ScriptLineOffsetGetter, nullptr,
                       attributes);
 }
 
 
 //
 // Accessors::ScriptType
 //
 
 
 void Accessors::ScriptTypeGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   Object* res =
       Smi::FromInt(Script::cast(JSValue::cast(object)->value())->type());
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(res, isolate)));
 }
 
 
-void Accessors::ScriptTypeSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptTypeInfo(
       Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(
       isolate->factory()->InternalizeOneByteString(STATIC_CHAR_VECTOR("type")));
-  return MakeAccessor(isolate,
-                      name,
-                      &ScriptTypeGetter,
-                      &ScriptTypeSetter,
-                      attributes);
+  return MakeAccessor(isolate, name, &ScriptTypeGetter, nullptr, attributes);
 }
 
 
 //
 // Accessors::ScriptCompilationType
 //
 
 
 void Accessors::ScriptCompilationTypeGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   Object* res = Smi::FromInt(
       Script::cast(JSValue::cast(object)->value())->compilation_type());
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(res, isolate)));
 }
 
 
-void Accessors::ScriptCompilationTypeSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptCompilationTypeInfo(
       Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(isolate->factory()->InternalizeOneByteString(
       STATIC_CHAR_VECTOR("compilation_type")));
-  return MakeAccessor(isolate,
-                      name,
-                      &ScriptCompilationTypeGetter,
-                      &ScriptCompilationTypeSetter,
+  return MakeAccessor(isolate, name, &ScriptCompilationTypeGetter, nullptr,
                       attributes);
 }
 
 
 //
 // Accessors::ScriptGetLineEnds
 //
 
 
 void Accessors::ScriptLineEndsGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   HandleScope scope(isolate);
   Handle<Object> object = Utils::OpenHandle(*info.This());
   Handle<Script> script(
       Script::cast(Handle<JSValue>::cast(object)->value()), isolate);
   Script::InitLineEnds(script);
   DCHECK(script->line_ends()->IsFixedArray());
   Handle<FixedArray> line_ends(FixedArray::cast(script->line_ends()));
   // We do not want anyone to modify this array from JS.
   DCHECK(*line_ends == isolate->heap()->empty_fixed_array() ||
          line_ends->map() == isolate->heap()->fixed_cow_array_map());
   Handle<JSArray> js_array =
       isolate->factory()->NewJSArrayWithElements(line_ends);
   info.GetReturnValue().Set(Utils::ToLocal(js_array));
 }
 
 
-void Accessors::ScriptLineEndsSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptLineEndsInfo(
       Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(isolate->factory()->InternalizeOneByteString(
       STATIC_CHAR_VECTOR("line_ends")));
-  return MakeAccessor(isolate,
-                      name,
-                      &ScriptLineEndsGetter,
-                      &ScriptLineEndsSetter,
+  return MakeAccessor(isolate, name, &ScriptLineEndsGetter, nullptr,
                       attributes);
 }
 
 
 //
 // Accessors::ScriptSourceUrl
 //
 
 
 void Accessors::ScriptSourceUrlGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   Object* url = Script::cast(JSValue::cast(object)->value())->source_url();
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(url, isolate)));
 }
 
 
-void Accessors::ScriptSourceUrlSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptSourceUrlInfo(
       Isolate* isolate, PropertyAttributes attributes) {
-  return MakeAccessor(isolate,
-                      isolate->factory()->source_url_string(),
-                      &ScriptSourceUrlGetter,
-                      &ScriptSourceUrlSetter,
-                      attributes);
+  return MakeAccessor(isolate, isolate->factory()->source_url_string(),
+                      &ScriptSourceUrlGetter, nullptr, attributes);
 }
 
 
 //
 // Accessors::ScriptSourceMappingUrl
 //
 
 
 void Accessors::ScriptSourceMappingUrlGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   Object* url =
       Script::cast(JSValue::cast(object)->value())->source_mapping_url();
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(url, isolate)));
 }
 
 
-void Accessors::ScriptSourceMappingUrlSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptSourceMappingUrlInfo(
       Isolate* isolate, PropertyAttributes attributes) {
-  return MakeAccessor(isolate,
-                      isolate->factory()->source_mapping_url_string(),
-                      &ScriptSourceMappingUrlGetter,
-                      &ScriptSourceMappingUrlSetter,
-                      attributes);
+  return MakeAccessor(isolate, isolate->factory()->source_mapping_url_string(),
+                      &ScriptSourceMappingUrlGetter, nullptr, attributes);
 }
 
 
 //
 // Accessors::ScriptIsEmbedderDebugScript
 //
 
 
 void Accessors::ScriptIsEmbedderDebugScriptGetter(
     v8::Local<v8::Name> name, const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   bool is_embedder_debug_script = Script::cast(JSValue::cast(object)->value())
                                       ->origin_options()
                                       .IsEmbedderDebugScript();
   Object* res = *isolate->factory()->ToBoolean(is_embedder_debug_script);
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(res, isolate)));
 }
 
 
-void Accessors::ScriptIsEmbedderDebugScriptSetter(
-    v8::Local<v8::Name> name, v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptIsEmbedderDebugScriptInfo(
     Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(isolate->factory()->InternalizeOneByteString(
       STATIC_CHAR_VECTOR("is_debugger_script")));
   return MakeAccessor(isolate, name, &ScriptIsEmbedderDebugScriptGetter,
-                      &ScriptIsEmbedderDebugScriptSetter, attributes);
+                      nullptr, attributes);
 }
 
 
 //
 // Accessors::ScriptGetContextData
 //
 
 
 void Accessors::ScriptContextDataGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   DisallowHeapAllocation no_allocation;
   HandleScope scope(isolate);
   Object* object = *Utils::OpenHandle(*info.This());
   Object* res = Script::cast(JSValue::cast(object)->value())->context_data();
   info.GetReturnValue().Set(Utils::ToLocal(Handle<Object>(res, isolate)));
 }
 
 
-void Accessors::ScriptContextDataSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptContextDataInfo(
       Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(isolate->factory()->InternalizeOneByteString(
       STATIC_CHAR_VECTOR("context_data")));
-  return MakeAccessor(isolate,
-                      name,
-                      &ScriptContextDataGetter,
-                      &ScriptContextDataSetter,
+  return MakeAccessor(isolate, name, &ScriptContextDataGetter, nullptr,
                       attributes);
 }
 
 
 //
 // Accessors::ScriptGetEvalFromScript
 //
 
 
 void Accessors::ScriptEvalFromScriptGetter(
@@ skipping 11 matching lines @@
     if (eval_from_shared->script()->IsScript()) {
       Handle<Script> eval_from_script(Script::cast(eval_from_shared->script()));
       result = Script::GetWrapper(eval_from_script);
     }
   }
 
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
 
-void Accessors::ScriptEvalFromScriptSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptEvalFromScriptInfo(
       Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(isolate->factory()->InternalizeOneByteString(
       STATIC_CHAR_VECTOR("eval_from_script")));
-  return MakeAccessor(isolate,
-                      name,
-                      &ScriptEvalFromScriptGetter,
-                      &ScriptEvalFromScriptSetter,
+  return MakeAccessor(isolate, name, &ScriptEvalFromScriptGetter, nullptr,
                       attributes);
 }
 
 
 //
 // Accessors::ScriptGetEvalFromScriptPosition
 //
 
 
 void Accessors::ScriptEvalFromScriptPositionGetter(
@@ skipping 10 matching lines @@
         script->eval_from_shared())->code());
     result = Handle<Object>(Smi::FromInt(code->SourcePosition(
                                 code->instruction_start() +
                                 script->eval_from_instructions_offset())),
                             isolate);
   }
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
 
-void Accessors::ScriptEvalFromScriptPositionSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptEvalFromScriptPositionInfo(
       Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(isolate->factory()->InternalizeOneByteString(
       STATIC_CHAR_VECTOR("eval_from_script_position")));
-  return MakeAccessor(isolate,
-                      name,
-                      &ScriptEvalFromScriptPositionGetter,
-                      &ScriptEvalFromScriptPositionSetter,
-                      attributes);
+  return MakeAccessor(isolate, name, &ScriptEvalFromScriptPositionGetter,
+                      nullptr, attributes);
 }
 
 
 //
 // Accessors::ScriptGetEvalFromFunctionName
 //
 
 
 void Accessors::ScriptEvalFromFunctionNameGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   HandleScope scope(isolate);
   Handle<Object> object = Utils::OpenHandle(*info.This());
   Handle<Script> script(
       Script::cast(Handle<JSValue>::cast(object)->value()), isolate);
   Handle<Object> result;
   Handle<SharedFunctionInfo> shared(
       SharedFunctionInfo::cast(script->eval_from_shared()));
   // Find the name of the function calling eval.
   if (!shared->name()->IsUndefined()) {
     result = Handle<Object>(shared->name(), isolate);
   } else {
     result = Handle<Object>(shared->inferred_name(), isolate);
   }
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
 
-void Accessors::ScriptEvalFromFunctionNameSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> value,
-    const v8::PropertyCallbackInfo<void>& info) {
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::ScriptEvalFromFunctionNameInfo(
       Isolate* isolate, PropertyAttributes attributes) {
   Handle<String> name(isolate->factory()->InternalizeOneByteString(
       STATIC_CHAR_VECTOR("eval_from_function_name")));
-  return MakeAccessor(isolate,
-                      name,
-                      &ScriptEvalFromFunctionNameGetter,
-                      &ScriptEvalFromFunctionNameSetter,
+  return MakeAccessor(isolate, name, &ScriptEvalFromFunctionNameGetter, nullptr,
                       attributes);
 }
 
 
 //
 // Accessors::FunctionPrototype
 //
 
 static Handle<Object> GetFunctionPrototype(Isolate* isolate,
                                            Handle<JSFunction> function) {
@@ skipping 97 matching lines @@
       length = function->shared()->length();
     }
     if (isolate->has_pending_exception()) {
       isolate->OptionalRescheduleException(false);
     }
   }
   Handle<Object> result(Smi::FromInt(length), isolate);
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
-
-MUST_USE_RESULT static MaybeHandle<Object> ReplaceAccessorWithDataProperty(
-    Isolate* isolate, Handle<JSObject> object, Handle<Name> name,
-    Handle<Object> value, bool is_observed, Handle<Object> old_value) {
-  LookupIterator it(object, name);
-  CHECK_EQ(LookupIterator::ACCESSOR, it.state());
-  DCHECK(it.HolderIsReceiverOrHiddenPrototype());
-  it.ReconfigureDataProperty(value, it.property_details().attributes());
-
-  if (is_observed && !old_value->SameValue(*value)) {
-    return JSObject::EnqueueChangeRecord(object, "update", name, old_value);
-  }
-
-  return value;
-}
-
-
-MUST_USE_RESULT static MaybeHandle<Object> SetFunctionLength(
-    Isolate* isolate, Handle<JSFunction> function, Handle<Object> value) {
-  Handle<Object> old_value;
-  bool is_observed = function->map()->is_observed();
-  if (is_observed) {
-    old_value = handle(Smi::FromInt(function->shared()->length()), isolate);
-  }
-
-  return ReplaceAccessorWithDataProperty(isolate, function,
-                                         isolate->factory()->length_string(),
-                                         value, is_observed, old_value);
-}
-
-
-void Accessors::FunctionLengthSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> val,
+void Accessors::ObservedReconfigureToDataProperty(
+    v8::Local<v8::Name> key, v8::Local<v8::Value> val,
     const v8::PropertyCallbackInfo<void>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   HandleScope scope(isolate);
+  Handle<JSObject> receiver =
+      Handle<JSObject>::cast(Utils::OpenHandle(*info.This()));
+  Handle<JSObject> holder =
+      Handle<JSObject>::cast(Utils::OpenHandle(*info.Holder()));
+  Handle<Name> name = Utils::OpenHandle(*key);
   Handle<Object> value = Utils::OpenHandle(*val);
-
-  Handle<JSFunction> object =
-      Handle<JSFunction>::cast(Utils::OpenHandle(*info.Holder()));
-  if (SetFunctionLength(isolate, object, value).is_null()) {
-    isolate->OptionalRescheduleException(false);
-  }
+  MaybeHandle<Object> result = ReplaceAccessorWithDataProperty(
+      isolate, receiver, holder, name, value, true);
+  if (result.is_null()) isolate->OptionalRescheduleException(false);
 }
 
 
 Handle<AccessorInfo> Accessors::FunctionLengthInfo(
       Isolate* isolate, PropertyAttributes attributes) {
-  return MakeAccessor(isolate,
-                      isolate->factory()->length_string(),
-                      &FunctionLengthGetter,
-                      &FunctionLengthSetter,
+  return MakeAccessor(isolate, isolate->factory()->length_string(),
+                      &FunctionLengthGetter, &ObservedReconfigureToDataProperty,
                       attributes);
 }
 
 
 //
 // Accessors::FunctionName
 //
 
 
 void Accessors::FunctionNameGetter(
     v8::Local<v8::Name> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   HandleScope scope(isolate);
   Handle<JSFunction> function =
       Handle<JSFunction>::cast(Utils::OpenHandle(*info.Holder()));
   Handle<Object> result;
   if (function->shared()->name_should_print_as_anonymous()) {
     result = isolate->factory()->anonymous_string();
   } else {
     result = handle(function->shared()->name(), isolate);
   }
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
-
-MUST_USE_RESULT static MaybeHandle<Object> SetFunctionName(
-    Isolate* isolate, Handle<JSFunction> function, Handle<Object> value) {
-  Handle<Object> old_value;
-  bool is_observed = function->map()->is_observed();
-  if (is_observed) {
-    old_value = handle(function->shared()->name(), isolate);
-  }
-
-  return ReplaceAccessorWithDataProperty(isolate, function,
-                                         isolate->factory()->name_string(),
-                                         value, is_observed, old_value);
-}
-
-
-void Accessors::FunctionNameSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> val,
-    const v8::PropertyCallbackInfo<void>& info) {
-  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
-  HandleScope scope(isolate);
-  Handle<Object> value = Utils::OpenHandle(*val);
-
-  Handle<JSFunction> object =
-      Handle<JSFunction>::cast(Utils::OpenHandle(*info.Holder()));
-  if (SetFunctionName(isolate, object, value).is_null()) {
-    isolate->OptionalRescheduleException(false);
-  }
-}
-
-
 Handle<AccessorInfo> Accessors::FunctionNameInfo(
       Isolate* isolate, PropertyAttributes attributes) {
-  return MakeAccessor(isolate,
-                      isolate->factory()->name_string(),
-                      &FunctionNameGetter,
-                      &FunctionNameSetter,
+  return MakeAccessor(isolate, isolate->factory()->name_string(),
+                      &FunctionNameGetter, &ObservedReconfigureToDataProperty,
                       attributes);
 }
 
 
 //
 // Accessors::FunctionArguments
 //
 
 
 static Handle<Object> ArgumentsForInlinedFunction(
@@ skipping 107 matching lines @@
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(info.GetIsolate());
   HandleScope scope(isolate);
   Handle<JSFunction> function =
       Handle<JSFunction>::cast(Utils::OpenHandle(*info.Holder()));
   Handle<Object> result = GetFunctionArguments(isolate, function);
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
 
-void Accessors::FunctionArgumentsSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> val,
-    const v8::PropertyCallbackInfo<void>& info) {
-  // Function arguments is non writable, non configurable.
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::FunctionArgumentsInfo(
       Isolate* isolate, PropertyAttributes attributes) {
-  return MakeAccessor(isolate,
-                      isolate->factory()->arguments_string(),
-                      &FunctionArgumentsGetter,
-                      &FunctionArgumentsSetter,
-                      attributes);
+  return MakeAccessor(isolate, isolate->factory()->arguments_string(),
+                      &FunctionArgumentsGetter, nullptr, attributes);
 }
 
 
 //
 // Accessors::FunctionCaller
 //
 
 
 static inline bool AllowAccessToFunction(Context* current_context,
                                          JSFunction* function) {
@@ skipping 109 matching lines @@
   Handle<JSFunction> caller;
   if (maybe_caller.ToHandle(&caller)) {
     result = caller;
   } else {
     result = isolate->factory()->null_value();
   }
   info.GetReturnValue().Set(Utils::ToLocal(result));
 }
 
 
-void Accessors::FunctionCallerSetter(
-    v8::Local<v8::Name> name,
-    v8::Local<v8::Value> val,
-    const v8::PropertyCallbackInfo<void>& info) {
-  // Function caller is non writable, non configurable.
-  UNREACHABLE();
-}
-
-
 Handle<AccessorInfo> Accessors::FunctionCallerInfo(
       Isolate* isolate, PropertyAttributes attributes) {
-  return MakeAccessor(isolate,
-                      isolate->factory()->caller_string(),
-                      &FunctionCallerGetter,
-                      &FunctionCallerSetter,
-                      attributes);
+  return MakeAccessor(isolate, isolate->factory()->caller_string(),
+                      &FunctionCallerGetter, nullptr, attributes);
 }
 
 
 //
 // Accessors::MakeModuleExport
 //
 
 static void ModuleGetExport(v8::Local<v8::Name> property,
                             const v8::PropertyCallbackInfo<v8::Value>& info) {
   JSModule* instance = JSModule::cast(*v8::Utils::OpenHandle(*info.Holder()));
@@ skipping 43 matching lines @@
   Isolate* isolate = name->GetIsolate();
   Handle<AccessorInfo> info = MakeAccessor(isolate, name, &ModuleGetExport,
                                            &ModuleSetExport, attributes);
   info->set_data(Smi::FromInt(index));
   return info;
 }
 
 
 }  // namespace internal
 }  // namespace v8