Make maps in monomorphic IC stubs weak.

src/objects-debug.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 622 matching lines @@
     it.rinfo()->Verify();
     // Ensure that GC will not iterate twice over the same pointer.
     if (RelocInfo::IsGCRelocMode(it.rinfo()->rmode())) {
       CHECK(it.rinfo()->pc() != last_gc_pc);
       last_gc_pc = it.rinfo()->pc();
     }
   }
 }
 
 
+static bool CodeListContains(Object* head, Code* code) {
+  while (!head->IsUndefined()) {
+    if (head == code) return true;
+    head = Code::cast(head)->next_code_link();
+  }
+  return false;
+}
+
+
 void Code::VerifyEmbeddedObjectsDependency() {
+  if (!CanContainWeakObjects()) return;
   int mode_mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
   for (RelocIterator it(this, mode_mask); !it.done(); it.next()) {
     Object* obj = it.rinfo()->target_object();
     if (IsWeakObject(obj)) {
       if (obj->IsMap()) {
         Map* map = Map::cast(obj);
-        CHECK(map->dependent_code()->Contains(
-            DependentCode::kWeaklyEmbeddedGroup, this));
+        if (is_optimized_code()) {
+          CHECK(map->dependent_code()->Contains(
+              DependentCode::kWeaklyEmbeddedGroup, this));
+        } else {
+          CHECK(CodeListContains(map->dependent_ic(), this));
+        }
       } else if (obj->IsJSObject()) {
         Object* raw_table = GetIsolate()->heap()->weak_object_to_code_table();
         WeakHashTable* table = WeakHashTable::cast(raw_table);
         CHECK(DependentCode::cast(table->Lookup(obj))->Contains(
             DependentCode::kWeaklyEmbeddedGroup, this));
       }
     }
   }
 }
 
@@ skipping 497 matching lines @@
   for (int i = 0; i < number_of_transitions(); ++i) {
     if (!CheckOneBackPointer(current_map, GetTarget(i))) return false;
   }
   return true;
 }
 
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal