Optimize AOT's switchable calls for the monomorphic case.

runtime/lib/stacktrace.cc

 // Copyright (c) 2013, 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 "lib/stacktrace.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/exceptions.h"
 #include "vm/object_store.h"
 #include "vm/runtime_entry.h"
 #include "vm/stack_frame.h"
 
 namespace dart {
 
 static void IterateFrames(const GrowableObjectArray& code_list,
                           const GrowableObjectArray& pc_offset_list,
                           int skip_frames) {
   StackFrameIterator frames(StackFrameIterator::kDontValidateFrames);
   StackFrame* frame = frames.NextFrame();
   ASSERT(frame != NULL);  // We expect to find a dart invocation frame.
   Code& code = Code::Handle();
   Smi& offset = Smi::Handle();
   while (frame != NULL) {
     if (frame->IsDartFrame()) {
       if (skip_frames > 0) {
         skip_frames--;
       } else {
         code = frame->LookupDartCode();
-        offset = Smi::New(frame->pc() - code.EntryPoint());
+        offset = Smi::New(frame->pc() - code.PayloadStart());
         code_list.Add(code);
         pc_offset_list.Add(offset);
       }
     }
     frame = frames.NextFrame();
   }
 }
 
 // Creates a Stacktrace object from the current stack.
 //
@@ skipping 31 matching lines @@
     frame = frames.NextFrame();
   }
 }
 
 DEFINE_NATIVE_ENTRY(StackTrace_current, 0) {
   const Stacktrace& stacktrace = GetCurrentStacktrace(1);
   return stacktrace.raw();
 }
 
 }  // namespace dart