Add an IC for CompareNil operations

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 2092859cd55deebe68fbbd54d51bb43a3ff3ac12..c71163a99acba8ac22070694da39e2177df44cfc 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9129,6 +9129,22 @@ Map* Code::FindFirstMap() {
 }
 
 
+void Code::ReplaceFirstMap(Map* replace_with) {
+  ASSERT(is_inline_cache_stub());
+  AssertNoAllocation no_allocation;
+  int mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
+  for (RelocIterator it(this, mask); !it.done(); it.next()) {
+    RelocInfo* info = it.rinfo();
+    Object* object = info->target_object();
+    if (object->IsMap()) {
+      info->set_target_object(replace_with);
+      return;
+    }
+  }
+  UNREACHABLE();
+}
+
+
 void Code::FindAllMaps(MapHandleList* maps) {
   ASSERT(is_inline_cache_stub());
   AssertNoAllocation no_allocation;
@@ -9324,6 +9340,7 @@ const char* Code::Kind2String(Kind kind) {
     case UNARY_OP_IC: return "UNARY_OP_IC";
     case BINARY_OP_IC: return "BINARY_OP_IC";
     case COMPARE_IC: return "COMPARE_IC";
+    case COMPARE_NIL_IC: return "COMPARE_NIL_IC";
     case TO_BOOLEAN_IC: return "TO_BOOLEAN_IC";
   }
   UNREACHABLE();