Track representations of fields

src/runtime.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 231 matching lines @@
   bool should_transform =
       !is_result_from_cache && boilerplate->HasFastProperties();
   if (should_transform || has_function_literal) {
     // Normalize the properties of object to avoid n^2 behavior
     // when extending the object multiple properties. Indicate the number of
     // properties to be added.
     JSObject::NormalizeProperties(
         boilerplate, KEEP_INOBJECT_PROPERTIES, length / 2);
   }
 
+  // TODO(verwaest): This does not catch the case where the object stays in fast
+  // most from the beginning. However, since it may go slow by adding
+  // properties, currently only assume we'll ever be fast if we ensure
+  // converting it back to fast mode.
+  bool will_be_fast = should_transform && !has_function_literal;
   for (int index = 0; index < length; index +=2) {
     Handle<Object> key(constant_properties->get(index+0), isolate);
     Handle<Object> value(constant_properties->get(index+1), isolate);
     if (value->IsFixedArray()) {
       // The value contains the constant_properties of a
       // simple object or array literal.
       Handle<FixedArray> array = Handle<FixedArray>::cast(value);
       value = CreateLiteralBoilerplate(isolate, literals, array);
       if (value.is_null()) return value;
+    } else if (value->IsUndefined()) {
+      // TODO(verwaest): Support storage types in the boilerplate.
+      // if (will_be_fast) {
+      //   value = isolate->factory()->the_hole_value();
+      // } else {
+      //   value = Handle<Object>(Smi::FromInt(0), isolate);
+      // }
     }
     Handle<Object> result;
     uint32_t element_index = 0;
     if (key->IsInternalizedString()) {
       if (Handle<String>::cast(key)->AsArrayIndex(&element_index)) {
         // Array index as string (uint32).
         result = JSObject::SetOwnElement(
             boilerplate, element_index, value, kNonStrictMode);
       } else {
         Handle<String> name(String::cast(*key));
@@ skipping 21 matching lines @@
     // exception, the exception is converted to an empty handle in
     // the handle based operations.  In that case, we need to
     // convert back to an exception.
     if (result.is_null()) return result;
   }
 
   // Transform to fast properties if necessary. For object literals with
   // containing function literals we defer this operation until after all
   // computed properties have been assigned so that we can generate
   // constant function properties.
-  if (should_transform && !has_function_literal) {
+  if (will_be_fast) {
     JSObject::TransformToFastProperties(
         boilerplate, boilerplate->map()->unused_property_fields());
   }
 
   return boilerplate;
 }
 
 
 MaybeObject* TransitionElements(Handle<Object> object,
                                 ElementsKind to_kind,
@@ skipping 7163 matching lines @@
       Execution::New(Handle<JSFunction>::cast(bound_function),
                      total_argc, *param_data, &exception);
   if (exception) {
     return Failure::Exception();
   }
   ASSERT(!result.is_null());
   return *result;
 }
 
 
-static void TrySettingInlineConstructStub(Isolate* isolate,
-                                          Handle<JSFunction> function) {
-  Handle<Object> prototype = isolate->factory()->null_value();
-  if (function->has_instance_prototype()) {
-    prototype = Handle<Object>(function->instance_prototype(), isolate);
-  }
-  if (function->shared()->CanGenerateInlineConstructor(*prototype)) {
-    ConstructStubCompiler compiler(isolate);
-    Handle<Code> code = compiler.CompileConstructStub(function);
-    function->shared()->set_construct_stub(*code);
-  }
-}
+// static void TrySettingInlineConstructStub(Isolate* isolate,
+//                                           Handle<JSFunction> function) {
+//   Handle<Object> prototype = isolate->factory()->null_value();
+//   if (function->has_instance_prototype()) {
+//     prototype = Handle<Object>(function->instance_prototype(), isolate);
+//   }
+//   if (function->shared()->CanGenerateInlineConstructor(*prototype)) {
+//     ConstructStubCompiler compiler(isolate);
+//     Handle<Code> code = compiler.CompileConstructStub(function);
+//     function->shared()->set_construct_stub(*code);
+//   }
+// }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_NewObject) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
 
   Handle<Object> constructor = args.at<Object>(0);
 
   // If the constructor isn't a proper function we throw a type error.
   if (!constructor->IsJSFunction()) {
@@ skipping 45 matching lines @@
 
   Handle<SharedFunctionInfo> shared(function->shared(), isolate);
   if (!function->has_initial_map() &&
       shared->IsInobjectSlackTrackingInProgress()) {
     // The tracking is already in progress for another function. We can only
     // track one initial_map at a time, so we force the completion before the
     // function is called as a constructor for the first time.
     shared->CompleteInobjectSlackTracking();
   }
 
-  bool first_allocation = !shared->live_objects_may_exist();
+  // bool first_allocation = !shared->live_objects_may_exist();
   Handle<JSObject> result = isolate->factory()->NewJSObject(function);
   RETURN_IF_EMPTY_HANDLE(isolate, result);
   // Delay setting the stub if inobject slack tracking is in progress.
-  if (first_allocation && !shared->IsInobjectSlackTrackingInProgress()) {
-    TrySettingInlineConstructStub(isolate, function);
-  }
+  // if (first_allocation && !shared->IsInobjectSlackTrackingInProgress()) {
+  //   TrySettingInlineConstructStub(isolate, function);
+  // }
 
   isolate->counters()->constructed_objects()->Increment();
   isolate->counters()->constructed_objects_runtime()->Increment();
 
   return *result;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FinalizeInstanceSize) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
 
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
   function->shared()->CompleteInobjectSlackTracking();
-  TrySettingInlineConstructStub(isolate, function);
+  // TrySettingInlineConstructStub(isolate, function);
 
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_LazyCompile) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
 
   Handle<JSFunction> function = args.at<JSFunction>(0);
@@ skipping 5696 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal