Fix context register allocation in LTransitionElementsKind.

src/deoptimizer.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1504 matching lines @@
            top_address + output_frame_offset, output_frame_offset, value);
   }
 
   // The context can be gotten from the input frame.
   Register context_reg = StubFailureTrampolineFrame::context_register();
   input_frame_offset -= kPointerSize;
   value = input_->GetFrameSlot(input_frame_offset);
   output_frame->SetRegister(context_reg.code(), value);
   output_frame_offset -= kPointerSize;
   output_frame->SetFrameSlot(output_frame_offset, value);
+  ASSERT(reinterpret_cast<Object*>(value)->IsContext());
   if (trace_scope_ != NULL) {
     PrintF(trace_scope_->file(),
            "    0x%08" V8PRIxPTR ": [top + %d] <- 0x%08"
            V8PRIxPTR " ; context\n",
            top_address + output_frame_offset, output_frame_offset, value);
   }
 
   // A marker value is used in place of the function.
   output_frame_offset -= kPointerSize;
   value = reinterpret_cast<intptr_t>(
@@ skipping 1519 matching lines @@
 
 void DeoptimizedFrameInfo::Iterate(ObjectVisitor* v) {
   v->VisitPointer(BitCast<Object**>(&function_));
   v->VisitPointers(parameters_, parameters_ + parameters_count_);
   v->VisitPointers(expression_stack_, expression_stack_ + expression_count_);
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal