[wasm] reuse the first compiled module

src/snapshot/code-serializer.cc

Index: src/snapshot/code-serializer.cc
diff --git a/src/snapshot/code-serializer.cc b/src/snapshot/code-serializer.cc
index 8d2f5d933994cbab63e6451973137fe11c50496a..48e59cd148c04be032ecf7d473bc15aae1be69fa 100644
--- a/src/snapshot/code-serializer.cc
+++ b/src/snapshot/code-serializer.cc
@@ -98,6 +98,10 @@ void CodeSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
     UNREACHABLE();
   }
 
+  if (SkipOver(obj)) {
+    return SerializeGeneric(*isolate()->factory()->undefined_value(),

[bradnelson, 2016/09/02 16:56:59]

So the links contain undefined when serialized?

[Mircea Trofin, 2016/09/02 20:55:30]

Yes. The module obtained by deserializing this is its own separate
JSObject instance, with its own wasm module instances chain

+                            how_to_code, where_to_point);
+  }
   // Past this point we should not see any (context-specific) maps anymore.
   CHECK(!obj->IsMap());
   // There should be no references to the global object embedded.