Reland "[strong] Object literals create strong objects"

src/runtime/runtime-literals.cc

 // Copyright 2014 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/v8.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/arguments.h"
 #include "src/ast.h"
 #include "src/parser.h"
 #include "src/runtime/runtime.h"
 #include "src/runtime/runtime-utils.h"
 
 namespace v8 {
 namespace internal {
 
 static Handle<Map> ComputeObjectLiteralMap(
     Handle<Context> context, Handle<FixedArray> constant_properties,
-    bool* is_result_from_cache) {
+    bool is_strong, bool* is_result_from_cache) {
   int properties_length = constant_properties->length();
   int number_of_properties = properties_length / 2;
 
   for (int p = 0; p != properties_length; p += 2) {
     Object* key = constant_properties->get(p);
     uint32_t element_index = 0;
     if (key->ToArrayIndex(&element_index)) {
       // An index key does not require space in the property backing store.
       number_of_properties--;
     }
   }
   Isolate* isolate = context->GetIsolate();
   return isolate->factory()->ObjectLiteralMapFromCache(
-      context, number_of_properties, is_result_from_cache);
+      context, number_of_properties, is_strong, is_result_from_cache);
 }
 
 MUST_USE_RESULT static MaybeHandle<Object> CreateLiteralBoilerplate(
     Isolate* isolate, Handle<FixedArray> literals,
-    Handle<FixedArray> constant_properties);
+    Handle<FixedArray> constant_properties, bool is_strong);
 
 
 MUST_USE_RESULT static MaybeHandle<Object> CreateObjectLiteralBoilerplate(
     Isolate* isolate, Handle<FixedArray> literals,
     Handle<FixedArray> constant_properties, bool should_have_fast_elements,
-    bool has_function_literal) {
+    bool has_function_literal, bool is_strong) {
   Handle<Context> context = isolate->native_context();
 
   // In case we have function literals, we want the object to be in
   // slow properties mode for now. We don't go in the map cache because
   // maps with constant functions can't be shared if the functions are
   // not the same (which is the common case).
+  // TODO(rossberg): handle strong objects with function literals
   bool is_result_from_cache = false;
   Handle<Map> map = has_function_literal
                         ? Handle<Map>(context->object_function()->initial_map())
                         : ComputeObjectLiteralMap(context, constant_properties,
+                                                  is_strong,
                                                   &is_result_from_cache);
 
   PretenureFlag pretenure_flag =
       isolate->heap()->InNewSpace(*literals) ? NOT_TENURED : TENURED;
 
   Handle<JSObject> boilerplate =
       isolate->factory()->NewJSObjectFromMap(map, pretenure_flag);
 
   // Normalize the elements of the boilerplate to save space if needed.
   if (!should_have_fast_elements) JSObject::NormalizeElements(boilerplate);
@@ skipping 10 matching lines @@
   }
   // TODO(verwaest): Support tracking representations in the boilerplate.
   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);
       ASSIGN_RETURN_ON_EXCEPTION(
-          isolate, value, CreateLiteralBoilerplate(isolate, literals, array),
+          isolate, value,
+          CreateLiteralBoilerplate(isolate, literals, array, is_strong),
           Object);
     }
     MaybeHandle<Object> maybe_result;
     uint32_t element_index = 0;
     if (key->IsInternalizedString()) {
       if (Handle<String>::cast(key)->AsArrayIndex(&element_index)) {
         // Array index as string (uint32).
         if (value->IsUninitialized()) value = handle(Smi::FromInt(0), isolate);
         maybe_result =
             JSObject::SetOwnElement(boilerplate, element_index, value, SLOPPY);
@@ skipping 34 matching lines @@
     JSObject::MigrateSlowToFast(boilerplate,
                                 boilerplate->map()->unused_property_fields(),
                                 "FastLiteral");
   }
   return boilerplate;
 }
 
 
 MaybeHandle<Object> Runtime::CreateArrayLiteralBoilerplate(
     Isolate* isolate, Handle<FixedArray> literals,
-    Handle<FixedArray> elements) {
+    Handle<FixedArray> elements, bool is_strong) {
   // Create the JSArray.
   Handle<JSFunction> constructor = isolate->array_function();
 
   PretenureFlag pretenure_flag =
       isolate->heap()->InNewSpace(*literals) ? NOT_TENURED : TENURED;
 
   Handle<JSArray> object = Handle<JSArray>::cast(
       isolate->factory()->NewJSObject(constructor, pretenure_flag));
 
   ElementsKind constant_elements_kind =
       static_cast<ElementsKind>(Smi::cast(elements->get(0))->value());
   Handle<FixedArrayBase> constant_elements_values(
       FixedArrayBase::cast(elements->get(1)));
 
   {
     DisallowHeapAllocation no_gc;
     DCHECK(IsFastElementsKind(constant_elements_kind));
     Context* native_context = isolate->context()->native_context();
-    Object* maps_array = native_context->js_array_maps();
+    Object* maps_array = is_strong
+        ? native_context->js_array_strong_maps()
+        : native_context->js_array_maps();
     DCHECK(!maps_array->IsUndefined());
     Object* map = FixedArray::cast(maps_array)->get(constant_elements_kind);
     object->set_map(Map::cast(map));
   }
 
   Handle<FixedArrayBase> copied_elements_values;
   if (IsFastDoubleElementsKind(constant_elements_kind)) {
     copied_elements_values = isolate->factory()->CopyFixedDoubleArray(
         Handle<FixedDoubleArray>::cast(constant_elements_values));
   } else {
@@ skipping 15 matching lines @@
       Handle<FixedArray> fixed_array_values_copy =
           isolate->factory()->CopyFixedArray(fixed_array_values);
       copied_elements_values = fixed_array_values_copy;
       for (int i = 0; i < fixed_array_values->length(); i++) {
         if (fixed_array_values->get(i)->IsFixedArray()) {
           // The value contains the constant_properties of a
           // simple object or array literal.
           Handle<FixedArray> fa(FixedArray::cast(fixed_array_values->get(i)));
           Handle<Object> result;
           ASSIGN_RETURN_ON_EXCEPTION(
-              isolate, result, CreateLiteralBoilerplate(isolate, literals, fa),
+              isolate, result,
+              CreateLiteralBoilerplate(isolate, literals, fa, is_strong),
               Object);
           fixed_array_values_copy->set(i, *result);
         }
       }
     }
   }
   object->set_elements(*copied_elements_values);
   object->set_length(Smi::FromInt(copied_elements_values->length()));
 
   JSObject::ValidateElements(object);
   return object;
 }
 
 
 MUST_USE_RESULT static MaybeHandle<Object> CreateLiteralBoilerplate(
-    Isolate* isolate, Handle<FixedArray> literals, Handle<FixedArray> array) {
+    Isolate* isolate, Handle<FixedArray> literals, Handle<FixedArray> array,
+    bool is_strong) {
   Handle<FixedArray> elements = CompileTimeValue::GetElements(array);
   const bool kHasNoFunctionLiteral = false;
   switch (CompileTimeValue::GetLiteralType(array)) {
     case CompileTimeValue::OBJECT_LITERAL_FAST_ELEMENTS:
       return CreateObjectLiteralBoilerplate(isolate, literals, elements, true,
-                                            kHasNoFunctionLiteral);
+                                            kHasNoFunctionLiteral, is_strong);
     case CompileTimeValue::OBJECT_LITERAL_SLOW_ELEMENTS:
       return CreateObjectLiteralBoilerplate(isolate, literals, elements, false,
-                                            kHasNoFunctionLiteral);
+                                            kHasNoFunctionLiteral, is_strong);
     case CompileTimeValue::ARRAY_LITERAL:
       return Runtime::CreateArrayLiteralBoilerplate(isolate, literals,
-                                                    elements);
+                                                    elements, is_strong);
     default:
       UNREACHABLE();
       return MaybeHandle<Object>();
   }
 }
 
 
 RUNTIME_FUNCTION(Runtime_CreateObjectLiteral) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 4);
   CONVERT_ARG_HANDLE_CHECKED(FixedArray, literals, 0);
   CONVERT_SMI_ARG_CHECKED(literals_index, 1);
   CONVERT_ARG_HANDLE_CHECKED(FixedArray, constant_properties, 2);
   CONVERT_SMI_ARG_CHECKED(flags, 3);
   bool should_have_fast_elements = (flags & ObjectLiteral::kFastElements) != 0;
   bool has_function_literal = (flags & ObjectLiteral::kHasFunction) != 0;
   bool enable_mementos = (flags & ObjectLiteral::kDisableMementos) == 0;
+  bool is_strong = (flags & ObjectLiteral::kIsStrong) != 0;
 
   RUNTIME_ASSERT(literals_index >= 0 && literals_index < literals->length());
 
   // Check if boilerplate exists. If not, create it first.
   Handle<Object> literal_site(literals->get(literals_index), isolate);
   Handle<AllocationSite> site;
   Handle<JSObject> boilerplate;
   if (*literal_site == isolate->heap()->undefined_value()) {
     Handle<Object> raw_boilerplate;
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
         isolate, raw_boilerplate,
         CreateObjectLiteralBoilerplate(isolate, literals, constant_properties,
                                        should_have_fast_elements,
-                                       has_function_literal));
+                                       has_function_literal, is_strong));
     boilerplate = Handle<JSObject>::cast(raw_boilerplate);
 
     AllocationSiteCreationContext creation_context(isolate);
     site = creation_context.EnterNewScope();
     RETURN_FAILURE_ON_EXCEPTION(
         isolate, JSObject::DeepWalk(boilerplate, &creation_context));
     creation_context.ExitScope(site, boilerplate);
 
     // Update the functions literal and return the boilerplate.
     literals->set(literals_index, *site);
   } else {
     site = Handle<AllocationSite>::cast(literal_site);
     boilerplate =
         Handle<JSObject>(JSObject::cast(site->transition_info()), isolate);
   }
 
   AllocationSiteUsageContext usage_context(isolate, site, enable_mementos);
   usage_context.EnterNewScope();
   MaybeHandle<Object> maybe_copy =
       JSObject::DeepCopy(boilerplate, &usage_context);
   usage_context.ExitScope(site, boilerplate);
   Handle<Object> copy;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, copy, maybe_copy);
   return *copy;
 }
 
 
 MUST_USE_RESULT static MaybeHandle<AllocationSite> GetLiteralAllocationSite(
     Isolate* isolate, Handle<FixedArray> literals, int literals_index,
-    Handle<FixedArray> elements) {
+    Handle<FixedArray> elements, bool is_strong) {
   // Check if boilerplate exists. If not, create it first.
   Handle<Object> literal_site(literals->get(literals_index), isolate);
   Handle<AllocationSite> site;
   if (*literal_site == isolate->heap()->undefined_value()) {
     DCHECK(*elements != isolate->heap()->empty_fixed_array());
     Handle<Object> boilerplate;
     ASSIGN_RETURN_ON_EXCEPTION(
         isolate, boilerplate,
-        Runtime::CreateArrayLiteralBoilerplate(isolate, literals, elements),
+        Runtime::CreateArrayLiteralBoilerplate(isolate, literals, elements,
+                                               is_strong),
         AllocationSite);
 
     AllocationSiteCreationContext creation_context(isolate);
     site = creation_context.EnterNewScope();
     if (JSObject::DeepWalk(Handle<JSObject>::cast(boilerplate),
                            &creation_context).is_null()) {
       return Handle<AllocationSite>::null();
     }
     creation_context.ExitScope(site, Handle<JSObject>::cast(boilerplate));
 
     literals->set(literals_index, *site);
   } else {
     site = Handle<AllocationSite>::cast(literal_site);
   }
 
   return site;
 }
 
 
 static MaybeHandle<JSObject> CreateArrayLiteralImpl(Isolate* isolate,
                                                     Handle<FixedArray> literals,
                                                     int literals_index,
                                                     Handle<FixedArray> elements,
                                                     int flags) {
   RUNTIME_ASSERT_HANDLIFIED(
       literals_index >= 0 && literals_index < literals->length(), JSObject);
   Handle<AllocationSite> site;
+  bool is_strong = (flags & ArrayLiteral::kIsStrong) != 0;
   ASSIGN_RETURN_ON_EXCEPTION(
       isolate, site,
-      GetLiteralAllocationSite(isolate, literals, literals_index, elements),
+      GetLiteralAllocationSite(isolate, literals, literals_index, elements,
+                               is_strong),
       JSObject);
 
   bool enable_mementos = (flags & ArrayLiteral::kDisableMementos) == 0;
   Handle<JSObject> boilerplate(JSObject::cast(site->transition_info()));
   AllocationSiteUsageContext usage_context(isolate, site, enable_mementos);
   usage_context.EnterNewScope();
   JSObject::DeepCopyHints hints = (flags & ArrayLiteral::kShallowElements) == 0
                                       ? JSObject::kNoHints
                                       : JSObject::kObjectIsShallow;
   MaybeHandle<JSObject> copy =
@@ skipping 85 matching lines @@
         JSObject::TransitionElementsKind(boilerplate_object, transitioned_kind);
       }
     }
     FixedArray* object_array = FixedArray::cast(object->elements());
     object_array->set(store_index, *value);
   }
   return *object;
 }
 }
 }  // namespace v8::internal