Allow the global object to be frozen through the global template

src/api-natives.cc

 // Copyright 2015 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/api-natives.h"
 
 #include "src/api.h"
 #include "src/isolate-inl.h"
 #include "src/lookup.h"
 #include "src/messages.h"
@@ skipping 595 matching lines @@
 
   if (prototype->IsTheHole(isolate)) {
     prototype = isolate->factory()->NewFunctionPrototype(result);
   } else {
     JSObject::AddProperty(Handle<JSObject>::cast(prototype),
                           isolate->factory()->constructor_string(), result,
                           DONT_ENUM);
   }
 
   int internal_field_count = 0;
+  bool immutable_proto = false;
   if (!obj->instance_template()->IsUndefined(isolate)) {
     Handle<ObjectTemplateInfo> instance_template = Handle<ObjectTemplateInfo>(
         ObjectTemplateInfo::cast(obj->instance_template()));
     internal_field_count = instance_template->internal_field_count();
+    immutable_proto = instance_template->immutable_proto();
   }
 
   // TODO(svenpanne) Kill ApiInstanceType and refactor things by generalizing
   // JSObject::GetHeaderSize.
   int instance_size = kPointerSize * internal_field_count;
   InstanceType type;
   switch (instance_type) {
     case JavaScriptObjectType:
       if (!obj->needs_access_check() &&
           obj->named_property_handler()->IsUndefined(isolate) &&
@@ skipping 13 matching lines @@
       instance_size += JSGlobalProxy::kSize;
       break;
     default:
       UNREACHABLE();
       type = JS_OBJECT_TYPE;  // Keep the compiler happy.
       break;
   }
 
   Handle<Map> map =
       isolate->factory()->NewMap(type, instance_size, FAST_HOLEY_SMI_ELEMENTS);
+
+  if (immutable_proto) map->set_immutable_proto(true);

[adamk, 2016/11/04 18:06:12]

Please put this down below with all the others (after the call to
SetInitialMap).

+
   JSFunction::SetInitialMap(result, map, Handle<JSObject>::cast(prototype));
 
   // Mark as undetectable if needed.
   if (obj->undetectable()) {
     map->set_is_undetectable();
   }
 
   // Mark as needs_access_check if needed.
   if (obj->needs_access_check()) {
     map->set_is_access_check_needed(true);
@@ skipping 11 matching lines @@
   if (!obj->instance_call_handler()->IsUndefined(isolate)) {
     map->set_is_callable();
     map->set_is_constructor(true);
   }
 
   return result;
 }
 
 }  // namespace internal
 }  // namespace v8