(early draft) Strict mode - throw exception on assignment to read only property.

src/objects.cc

 // Copyright 2010 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 1426 matching lines @@
       }
     }
   }
   return AddSlowProperty(name, value, attributes);
 }
 
 
 MaybeObject* JSObject::SetPropertyPostInterceptor(
     String* name,
     Object* value,
-    PropertyAttributes attributes) {
+    PropertyAttributes attributes,
+    StrictModeFlag strict) {
   // Check local property, ignore interceptor.
   LookupResult result;
   LocalLookupRealNamedProperty(name, &result);
   if (result.IsFound()) {
     // An existing property, a map transition or a null descriptor was
     // found.  Use set property to handle all these cases.
-    return SetProperty(&result, name, value, attributes);
+    return SetProperty(&result, name, value, attributes, strict);
   }
   // Add a new real property.
   return AddProperty(name, value, attributes);
 }
 
 
 MaybeObject* JSObject::ReplaceSlowProperty(String* name,
                                            Object* value,
                                            PropertyAttributes attributes) {
   StringDictionary* dictionary = property_dictionary();
@@ skipping 104 matching lines @@
     set_properties(FixedArray::cast(new_properties));
   }
   return FastPropertyAtPut(index, new_value);
 }
 
 
 
 MaybeObject* JSObject::SetPropertyWithInterceptor(
     String* name,
     Object* value,
-    PropertyAttributes attributes) {
+    PropertyAttributes attributes,
+    StrictModeFlag strict) {
   HandleScope scope;
   Handle<JSObject> this_handle(this);
   Handle<String> name_handle(name);
   Handle<Object> value_handle(value);
   Handle<InterceptorInfo> interceptor(GetNamedInterceptor());
   if (!interceptor->setter()->IsUndefined()) {
     LOG(ApiNamedPropertyAccess("interceptor-named-set", this, name));
     CustomArguments args(interceptor->data(), this, this);
     v8::AccessorInfo info(args.end());
     v8::NamedPropertySetter setter =
         v8::ToCData<v8::NamedPropertySetter>(interceptor->setter());
     v8::Handle<v8::Value> result;
     {
       // Leaving JavaScript.
       VMState state(EXTERNAL);
       Handle<Object> value_unhole(value->IsTheHole() ?
                                   Heap::undefined_value() :
                                   value);
       result = setter(v8::Utils::ToLocal(name_handle),
                       v8::Utils::ToLocal(value_unhole),
                       info);
     }
     RETURN_IF_SCHEDULED_EXCEPTION();
     if (!result.IsEmpty()) return *value_handle;
   }
   MaybeObject* raw_result =
       this_handle->SetPropertyPostInterceptor(*name_handle,
                                               *value_handle,
-                                              attributes);
+                                              attributes,
+                                              strict);
   RETURN_IF_SCHEDULED_EXCEPTION();
   return raw_result;
 }
 
 
 MaybeObject* JSObject::SetProperty(String* name,
                                    Object* value,
-                                   PropertyAttributes attributes) {
+                                   PropertyAttributes attributes,
+                                   StrictModeFlag strict) {
   LookupResult result;
   LocalLookup(name, &result);
-  return SetProperty(&result, name, value, attributes);
+  return SetProperty(&result, name, value, attributes, strict);
 }
 
 
 MaybeObject* JSObject::SetPropertyWithCallback(Object* structure,
                                                String* name,
                                                Object* value,
                                                JSObject* holder) {
   HandleScope scope;
 
   // We should never get here to initialize a const with the hole
@@ skipping 259 matching lines @@
   HandleScope scope;
   Handle<Object> value_handle(value);
   Top::ReportFailedAccessCheck(this, v8::ACCESS_SET);
   return *value_handle;
 }
 
 
 MaybeObject* JSObject::SetProperty(LookupResult* result,
                                    String* name,
                                    Object* value,
-                                   PropertyAttributes attributes) {
+                                   PropertyAttributes attributes,
+                                   StrictModeFlag strict) {
   // Make sure that the top context does not change when doing callbacks or
   // interceptor calls.
   AssertNoContextChange ncc;
 
   // Optimization for 2-byte strings often used as keys in a decompression
   // dictionary.  We make these short keys into symbols to avoid constantly
   // reallocating them.
   if (!name->IsSymbol() && name->length() <= 2) {
     Object* symbol_version;
     { MaybeObject* maybe_symbol_version = Heap::LookupSymbol(name);
       if (maybe_symbol_version->ToObject(&symbol_version)) {
         name = String::cast(symbol_version);
       }
     }
   }
 
   // Check access rights if needed.
   if (IsAccessCheckNeeded()
       && !Top::MayNamedAccess(this, name, v8::ACCESS_SET)) {
     return SetPropertyWithFailedAccessCheck(result, name, value, true);
   }
 
   if (IsJSGlobalProxy()) {
     Object* proto = GetPrototype();
     if (proto->IsNull()) return value;
     ASSERT(proto->IsJSGlobalObject());
-    return JSObject::cast(proto)->SetProperty(result, name, value, attributes);
+    return JSObject::cast(proto)->SetProperty(
+        result, name, value, attributes, strict);
   }
 
   if (!result->IsProperty() && !IsJSContextExtensionObject()) {
     // We could not find a local property so let's check whether there is an
     // accessor that wants to handle the property.
     LookupResult accessor_result;
     LookupCallbackSetterInPrototypes(name, &accessor_result);
     if (accessor_result.IsProperty()) {
       return SetPropertyWithCallback(accessor_result.GetCallbackObject(),
                                      name,
                                      value,
                                      accessor_result.holder());
     }
   }
   if (!result->IsFound()) {
     // Neither properties nor transitions found.
     return AddProperty(name, value, attributes);
   }
-  if (result->IsReadOnly() && result->IsProperty()) return value;
+  if (result->IsReadOnly() && result->IsProperty()) {
+    if (strict == kStrictMode) {
+      HandleScope scope;
+      Handle<String> key(name);
+      Handle<Object> holder(this);
+      Handle<Object> args[2] = { key, holder };
+      return Top::Throw(*Factory::NewTypeError("strict_rdonly_property",
+                                                HandleVector(args, 2)));
+
+    } else {
+      return value;
+    }
+  }
   // This is a real property that is not read-only, or it is a
   // transition or null descriptor and there are no setters in the prototypes.
   switch (result->type()) {
     case NORMAL:
       return SetNormalizedProperty(result, value);
     case FIELD:
       return FastPropertyAtPut(result->GetFieldIndex(), value);
     case MAP_TRANSITION:
       if (attributes == result->GetAttributes()) {
         // Only use map transition if the attributes match.
         return AddFastPropertyUsingMap(result->GetTransitionMap(),
                                        name,
                                        value);
       }
       return ConvertDescriptorToField(name, value, attributes);
     case CONSTANT_FUNCTION:
       // Only replace the function if necessary.
       if (value == result->GetConstantFunction()) return value;
       // Preserve the attributes of this existing property.
       attributes = result->GetAttributes();
       return ConvertDescriptorToField(name, value, attributes);
     case CALLBACKS:
       return SetPropertyWithCallback(result->GetCallbackObject(),
                                      name,
                                      value,
                                      result->holder());
     case INTERCEPTOR:
-      return SetPropertyWithInterceptor(name, value, attributes);
+      return SetPropertyWithInterceptor(name, value, attributes, strict);
     case CONSTANT_TRANSITION: {
       // If the same constant function is being added we can simply
       // transition to the target map.
       Map* target_map = result->GetTransitionMap();
       DescriptorArray* target_descriptors = target_map->instance_descriptors();
       int number = target_descriptors->SearchWithCache(name);
       ASSERT(number != DescriptorArray::kNotFound);
       ASSERT(target_descriptors->GetType(number) == CONSTANT_FUNCTION);
       JSFunction* function =
           JSFunction::cast(target_descriptors->GetValue(number));
@@ skipping 4296 matching lines @@
 
 void Code::PrintExtraICState(FILE* out, Kind kind, ExtraICState extra) {
   const char* name = NULL;
   switch (kind) {
     case CALL_IC:
       if (extra == STRING_INDEX_OUT_OF_BOUNDS) {
         name = "STRING_INDEX_OUT_OF_BOUNDS";
       }
       break;
     case STORE_IC:
-      if (extra == StoreIC::kStoreICStrict) {
+    case KEYED_STORE_IC:
+      if (extra == kStrictMode) {
         name = "STRICT";
       }
       break;
     default:
       break;
   }
   if (name != NULL) {
     PrintF(out, "extra_ic_state = %s\n", name);
   } else {
     PrintF(out, "etra_ic_state = %d\n", extra);
@@ skipping 3715 matching lines @@
   if (break_point_objects()->IsUndefined()) return 0;
   // Single beak point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif
 
 
 } }  // namespace v8::internal