[heap] Avoid the use of cells to point from code to new-space objects.

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index a7fd3b79d7bb799ea7414332645ac64dc178fcf0..a9461ee2e109044df1a0d65e41ddb46dea00391c 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -189,6 +189,11 @@ using v8::MemoryPressureLevel;
   V(FixedArray, detached_contexts, DetachedContexts)                           \
   V(ArrayList, retained_maps, RetainedMaps)                                    \
   V(WeakHashTable, weak_object_to_code_table, WeakObjectToCodeTable)           \
+  /* weak_new_space_object_to_code_list is an array of weak cells, where */    \
+  /* slots with even indices refer to the weak object, and the subsequent */   \
+  /* slots refer to the code with the reference to the weak object. */         \
+  V(ArrayList, weak_new_space_object_to_code_list,                             \
+    WeakNewSpaceObjectToCodeList)                                              \
   V(PropertyCell, array_protector, ArrayProtector)                             \
   V(Cell, is_concat_spreadable_protector, IsConcatSpreadableProtector)         \
   V(PropertyCell, empty_property_cell, EmptyPropertyCell)                      \
@@ -839,6 +844,9 @@ class Heap {
     return new_space_.IsAtMaximumCapacity() && maximum_size_scavenges_ == 0;
   }
 
+  void AddWeakNewSpaceObjectToCodeDependency(Handle<HeapObject> obj,
+                                             Handle<WeakCell> code);
+
   void AddWeakObjectToCodeDependency(Handle<HeapObject> obj,
                                      Handle<DependentCode> dep);
 
@@ -1099,6 +1107,8 @@ class Heap {
 
   // Write barrier support for object[offset] = o;
   inline void RecordWrite(Object* object, int offset, Object* o);
+  inline void RecordWriteIntoCode(Code* host, RelocInfo* rinfo, Object* target);
+  void RecordWriteIntoCodeSlow(Code* host, RelocInfo* rinfo, Object* target);
   inline void RecordFixedArrayElements(FixedArray* array, int offset,
                                        int length);