Remove CanRetainOtherContext since embedded objects are now weak.

src/type-info.cc

Index: src/type-info.cc
diff --git a/src/type-info.cc b/src/type-info.cc
index 1059c7aecd8796e4f31d0a9f4a9e3ff3354f4719..087e1db148b22f2c9943571ebde21d3223656c4a 100644
--- a/src/type-info.cc
+++ b/src/type-info.cc
@@ -52,12 +52,7 @@ Handle<Object> TypeFeedbackOracle::GetInfo(TypeFeedbackId ast_id) {
 Handle<Object> TypeFeedbackOracle::GetInfo(FeedbackVectorSlot slot) {
   DCHECK(slot.ToInt() >= 0 && slot.ToInt() < feedback_vector_->length());
   Object* obj = feedback_vector_->Get(slot);
-  if (!obj->IsJSFunction() ||
-      !CanRetainOtherContext(JSFunction::cast(obj), *native_context_)) {
-    DCHECK(!obj->IsMap());
-    return Handle<Object>(obj, isolate());
-  }
-  return Handle<Object>::cast(isolate()->factory()->undefined_value());
+  return Handle<Object>(obj, isolate());
 }
 
 
@@ -75,9 +70,7 @@ Handle<Object> TypeFeedbackOracle::GetInfo(FeedbackVectorICSlot slot) {
     obj = cell->value();
   }
 
-  if ((obj->IsJSFunction() &&
-       !CanRetainOtherContext(JSFunction::cast(obj), *native_context_)) ||
-      obj->IsAllocationSite() || obj->IsSymbol()) {
+  if (obj->IsJSFunction() || obj->IsAllocationSite() || obj->IsSymbol()) {
     return Handle<Object>(obj, isolate());
   }
 
@@ -248,12 +241,7 @@ void TypeFeedbackOracle::CompareType(TypeFeedbackId id,
 
   Handle<Map> map;
   Map* raw_map = code->FindFirstMap();
-  if (raw_map != NULL) {
-    if (Map::TryUpdate(handle(raw_map)).ToHandle(&map) &&
-        CanRetainOtherContext(*map, *native_context_)) {
-      map = Handle<Map>::null();
-    }
-  }
+  if (raw_map != NULL) Map::TryUpdate(handle(raw_map)).ToHandle(&map);
 
   if (code->is_compare_ic_stub()) {
     CompareICStub stub(code->stub_key(), isolate());
@@ -419,43 +407,6 @@ void TypeFeedbackOracle::CollectReceiverTypes(T* obj, Handle<Name> name,
 }
 
 
-// Check if a map originates from a given native context. We use this
-// information to filter out maps from different context to avoid
-// retaining objects from different tabs in Chrome via optimized code.
-bool TypeFeedbackOracle::CanRetainOtherContext(Map* map,
-                                               Context* native_context) {
-  Object* constructor = NULL;
-  while (!map->prototype()->IsNull()) {
-    constructor = map->GetConstructor();
-    if (!constructor->IsNull()) {
-      // If the constructor is not null or a JSFunction, we have to
-      // conservatively assume that it may retain a native context.
-      if (!constructor->IsJSFunction()) return true;
-      // Check if the constructor directly references a foreign context.
-      if (CanRetainOtherContext(JSFunction::cast(constructor),
-                                native_context)) {
-        return true;
-      }
-    }
-    map = HeapObject::cast(map->prototype())->map();
-  }
-  constructor = map->GetConstructor();
-  if (constructor->IsNull()) return false;
-  // If the constructor is not null or a JSFunction, we have to conservatively
-  // assume that it may retain a native context.
-  if (!constructor->IsJSFunction()) return true;
-  JSFunction* function = JSFunction::cast(constructor);
-  return CanRetainOtherContext(function, native_context);
-}
-
-
-bool TypeFeedbackOracle::CanRetainOtherContext(JSFunction* function,
-                                               Context* native_context) {
-  return function->context()->global_object() != native_context->global_object()
-      && function->context()->global_object() != native_context->builtins();
-}
-
-
 void TypeFeedbackOracle::CollectReceiverTypes(TypeFeedbackId ast_id,
                                               SmallMapList* types) {
   Handle<Object> object = GetInfo(ast_id);
@@ -479,8 +430,8 @@ void TypeFeedbackOracle::CollectReceiverTypes(T* obj, SmallMapList* types) {
   types->Reserve(maps.length(), zone());
   for (int i = 0; i < maps.length(); i++) {
     Handle<Map> map(maps.at(i));

[Erik Corry, 2015/03/26 11:20:57]

Perhaps you don't need this variable if it's only used one place.

-    if (!CanRetainOtherContext(*map, *native_context_)) {
-      types->AddMapIfMissing(map, zone());
+    if (IsRelevantFeedback(*map, *native_context_)) {
+      types->AddMapIfMissing(maps.at(i), zone());
     }
   }
 }