DBC: Fail cleanly when attempting to create an AOT or JIT app snapshot.

runtime/vm/intermediate_language_dbc.cc

Index: runtime/vm/intermediate_language_dbc.cc
diff --git a/runtime/vm/intermediate_language_dbc.cc b/runtime/vm/intermediate_language_dbc.cc
index f1be32dfcd7bebd59e64446839a7375eb9dc6133..02d095e2a7851472e70f84b14747ddf6787d066c 100644
--- a/runtime/vm/intermediate_language_dbc.cc
+++ b/runtime/vm/intermediate_language_dbc.cc
@@ -786,7 +786,7 @@ EMIT_NATIVE_CODE(NativeCall,
   ASSERT(!link_lazily());
   const ExternalLabel label(reinterpret_cast<uword>(native_c_function()));
   const intptr_t target_kidx =
-      __ object_pool_wrapper().FindImmediate(label.address());
+      __ object_pool_wrapper().FindNativeEntry(&label, kNotPatchable);

[zra, 2016/07/29 20:56:27]

Are there more places that we should be passing this?

[rmacnak, 2016/07/29 21:08:08]

This should be the only place with native entry in the pool. It's possible other
places could use kNotPatchable; doing so is a size optimization for sharing
object pool entries.

   const intptr_t argc_tag_kidx =
       __ object_pool_wrapper().FindImmediate(static_cast<uword>(argc_tag));
   __ PushConstant(target_kidx);