Make functions contexts in optimized code weak.

BUG=

Review URL: https://codereview.chromium.org/882913006

Cr-Commit-Position: refs/heads/master@{#26436}

src/lithium.cc

@@ -427,27 +427,23 @@ static void AddWeakObjectToCodeDependency(Isolate* isolate,
 void LChunk::RegisterWeakObjectsInOptimizedCode(Handle<Code> code) const {
   DCHECK(code->is_optimized_code());
   ZoneList<Handle<Map> > maps(1, zone());
-  ZoneList<Handle<JSObject> > objects(1, zone());
-  ZoneList<Handle<Cell> > cells(1, zone());
+  ZoneList<Handle<HeapObject> > objects(1, zone());
   int mode_mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT) |
                   RelocInfo::ModeMask(RelocInfo::CELL);
   for (RelocIterator it(*code, mode_mask); !it.done(); it.next()) {
     RelocInfo::Mode mode = it.rinfo()->rmode();
     if (mode == RelocInfo::CELL &&
         code->IsWeakObjectInOptimizedCode(it.rinfo()->target_cell())) {
-      Handle<Cell> cell(it.rinfo()->target_cell());
-      cells.Add(cell, zone());
+      objects.Add(Handle<HeapObject>(it.rinfo()->target_cell()), zone());
     } else if (mode == RelocInfo::EMBEDDED_OBJECT &&
                code->IsWeakObjectInOptimizedCode(it.rinfo()->target_object())) {
       if (it.rinfo()->target_object()->IsMap()) {
         Handle<Map> map(Map::cast(it.rinfo()->target_object()));
         maps.Add(map, zone());
-      } else if (it.rinfo()->target_object()->IsJSObject()) {
-        Handle<JSObject> object(JSObject::cast(it.rinfo()->target_object()));
+      } else {
+        Handle<HeapObject> object(
+            HeapObject::cast(it.rinfo()->target_object()));
         objects.Add(object, zone());
-      } else if (it.rinfo()->target_object()->IsCell()) {
-        Handle<Cell> cell(Cell::cast(it.rinfo()->target_object()));
-        cells.Add(cell, zone());
       }
     }
   }
@@ -457,9 +453,6 @@ void LChunk::RegisterWeakObjectsInOptimizedCode(Handle<Code> code) const {
   for (int i = 0; i < objects.length(); i++) {
     AddWeakObjectToCodeDependency(isolate(), objects.at(i), code);
   }
-  for (int i = 0; i < cells.length(); i++) {
-    AddWeakObjectToCodeDependency(isolate(), cells.at(i), code);
-  }
   if (FLAG_enable_ool_constant_pool) {
     code->constant_pool()->set_weak_object_state(
         ConstantPoolArray::WEAK_OBJECTS_IN_OPTIMIZED_CODE);

src/objects-inl.h

@@ -5234,10 +5234,17 @@ bool Code::IsWeakObjectInOptimizedCode(Object* object) {
     return Map::cast(object)->CanTransition() &&
            FLAG_weak_embedded_maps_in_optimized_code;
   }
-  if (object->IsJSObject() ||
-      (object->IsCell() && Cell::cast(object)->value()->IsJSObject())) {
+  if (object->IsCell()) object = Cell::cast(object)->value();
+  if (object->IsJSObject()) {
     return FLAG_weak_embedded_objects_in_optimized_code;
   }
+  if (object->IsFixedArray()) {
+    // Contexts of inlined functions are embedded in optimized code.
+    Map* map = HeapObject::cast(object)->map();
+    Heap* heap = map->GetHeap();
+    return FLAG_weak_embedded_objects_in_optimized_code &&
+           map == heap->function_context_map();
+  }
   return false;
 }