Make maps in monomorphic IC stubs weak.

src/objects-debug.cc

Index: src/objects-debug.cc
diff --git a/src/objects-debug.cc b/src/objects-debug.cc
index ba9ff65be0c4883b97685076fdeef82e9f528671..6f9b31b6abb98722a065641adee8612443594070 100644
--- a/src/objects-debug.cc
+++ b/src/objects-debug.cc
@@ -640,15 +640,29 @@ void Code::CodeVerify() {
 }
 
 
+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);