[heap] Fix a map creation data race with concurrent marking.

The race happens when an object transitions to a newly created map.
The map initializing stores can be reordered after object->set_map(map),
which will cause the concurrent marker to observe inconsistent map.

The fix is to use store-release when setting the map pointer and
acquire-load when reading the map in the concurrent marker.

BUG=chromium:694255

Change-Id: I4fd6bc27dd70ff1a30f56a4cec13310ccdd627c8
Reviewed-on: https://chromium-review.googlesource.com/528118
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45876}

src/builtins/builtins-array.cc

@@ -498,9 +498,9 @@ class ArrayConcatVisitor {
         isolate_->factory()->NewNumber(static_cast<double>(index_offset_));
     Handle<Map> map = JSObject::GetElementsTransitionMap(
         array, fast_elements() ? FAST_HOLEY_ELEMENTS : DICTIONARY_ELEMENTS);
-    array->set_map(*map);
     array->set_length(*length);
     array->set_elements(*storage_fixed_array());
+    array->synchronized_set_map(*map);
     return array;
   }
 

src/factory.cc

@@ -1864,8 +1864,8 @@ Handle<JSGlobalObject> Factory::NewJSGlobalObject(
   new_map->set_dictionary_map(true);
 
   // Set up the global object as a normalized object.
-  global->set_map(*new_map);
   global->set_properties(*dictionary);
+  global->synchronized_set_map(*new_map);
 
   // Make sure result is a global object with properties in dictionary.
   DCHECK(global->IsJSGlobalObject() && !global->HasFastProperties());

src/heap/concurrent-marking.cc

@@ -266,7 +266,8 @@ void ConcurrentMarking::Run() {
       if (new_space_top <= addr && addr < new_space_limit) {
         deque_->Push(object, MarkingThread::kConcurrent, TargetDeque::kBailout);
       } else {
-        bytes_marked += visitor_->Visit(object);
+        Map* map = object->synchronized_map();
+        bytes_marked += visitor_->Visit(map, object);
       }
     }
   }

src/heap/objects-visiting-inl.h

@@ -487,7 +487,12 @@ inline static bool HasSourceCode(Heap* heap, SharedFunctionInfo* info) {
 
 template <typename ResultType, typename ConcreteVisitor>
 ResultType HeapVisitor<ResultType, ConcreteVisitor>::Visit(HeapObject* object) {
-  Map* map = object->map();
+  return Visit(object->map(), object);
+}
+
+template <typename ResultType, typename ConcreteVisitor>
+ResultType HeapVisitor<ResultType, ConcreteVisitor>::Visit(Map* map,
+                                                           HeapObject* object) {
   ConcreteVisitor* visitor = static_cast<ConcreteVisitor*>(this);
   switch (static_cast<VisitorId>(map->visitor_id())) {
 #define CASE(type)   \

src/heap/objects-visiting.h

@@ -387,6 +387,7 @@ template <typename ResultType, typename ConcreteVisitor>
 class HeapVisitor : public ObjectVisitor {
  public:
   ResultType Visit(HeapObject* object);
+  ResultType Visit(Map* map, HeapObject* object);
 
  protected:
   // A guard predicate for visiting the object.

src/objects.cc

@@ -3822,7 +3822,7 @@ void JSObject::MigrateToMap(Handle<JSObject> object, Handle<Map> new_map,
     CHECK(new_map->is_dictionary_map());
 
     // Slow-to-slow migration is trivial.
-    object->set_map(*new_map);
+    object->synchronized_set_map(*new_map);
   } else if (!new_map->is_dictionary_map()) {
     MigrateFastToFast(object, new_map);
     if (old_map->is_prototype_map()) {
@@ -15298,7 +15298,7 @@ void JSObject::SetImmutableProto(Handle<JSObject> object) {
   if (map->is_immutable_proto()) return;
 
   Handle<Map> new_map = Map::TransitionToImmutableProto(map);
-  object->set_map(*new_map);
+  object->synchronized_set_map(*new_map);
 }
 
 void JSObject::EnsureCanContainElements(Handle<JSObject> object,

src/runtime/runtime-literals.cc

@@ -111,7 +111,7 @@ static Handle<Object> CreateArrayLiteralBoilerplate(
     Context* native_context = isolate->context()->native_context();
     Object* map =
         native_context->get(Context::ArrayMapIndex(constant_elements_kind));
-    object->set_map(Map::cast(map));
+    object->synchronized_set_map(Map::cast(map));
   }
 
   Handle<FixedArrayBase> copied_elements_values;