Ensure the debugger keeps a reference to code objects

runtime/vm/debugger_x64.cc

 // Copyright (c) 2011, 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.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/debugger.h"
 
 #include "vm/assembler.h"
@@ skipping 18 matching lines @@
   // At a minimum we have the closure object on the stack.
   ASSERT(num_actual_args > 0);
   // Stack pointer points to last argument that was pushed on the stack.
   uword closure_addr = sp() + ((num_actual_args - 1) * kWordSize);
   return reinterpret_cast<RawObject*>(
              *reinterpret_cast<uword*>(closure_addr));
 }
 
 
 uword CodeBreakpoint::OrigStubAddress() const {
-  const Code& code =
-      Code::Handle(Function::Handle(function_).unoptimized_code());
+  const Code& code = Code::Handle(code_);
   const Array& object_pool = Array::Handle(code.ObjectPool());
   uword offset = saved_value_ + kHeapObjectTag;
   ASSERT((offset % kWordSize) == 0);
   const intptr_t index = (offset - Array::data_offset()) / kWordSize;
   const uword stub_address = reinterpret_cast<uword>(object_pool.At(index));
   ASSERT(stub_address % kWordSize == 0);
   return stub_address;
 }
 
 
@@ skipping 35 matching lines @@
     default:
       UNREACHABLE();
   }
   is_enabled_ = false;
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64