Do not rely on code patching on DBC for lazy deoptimization.

runtime/vm/code_patcher.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 // Class for patching compiled code.
 
 #ifndef RUNTIME_VM_CODE_PATCHER_H_
 #define RUNTIME_VM_CODE_PATCHER_H_
 
 #include "vm/allocation.h"
 #include "vm/native_entry.h"
@@ skipping 50 matching lines @@
                                     ICData* ic_data);
 
   // Return target of an unoptimized static call and its ICData object
   // (calls target via a stub).
   static RawFunction* GetUnoptimizedStaticCallAt(uword return_address,
                                                  const Code& code,
                                                  ICData* ic_data);
 
   static intptr_t InstanceCallSizeInBytes();
 
-  static void InsertDeoptimizationCallAt(uword start);

[rmacnak, 2017/03/09 20:31:59]

Sweet!

-
   static void PatchPoolPointerCallAt(uword return_address,
                                      const Code& code,
                                      const Code& new_target);
 
   static void PatchSwitchableCallAt(uword return_address,
                                     const Code& caller_code,
                                     const Object& data,
                                     const Code& target);
   static RawObject* GetSwitchableCallDataAt(uword return_address,
                                             const Code& caller_code);
   static RawCode* GetSwitchableCallTargetAt(uword return_address,
                                             const Code& caller_code);
 
   static RawCode* GetNativeCallAt(uword return_address,
                                   const Code& code,
                                   NativeFunction* target);
 
   static void PatchNativeCallAt(uword return_address,
                                 const Code& code,
                                 NativeFunction target,
                                 const Code& trampoline);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_CODE_PATCHER_H_