Report deoptimization error in release mode.

src/deoptimizer.cc

 // Copyright 2012 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 517 matching lines @@
     }
   }
   PrintF("[couldn't find pc offset for node=%d]\n", id.ToInt());
   PrintF("[method: %s]\n", *shared->DebugName()->ToCString());
   // Print the source code if available.
   HeapStringAllocator string_allocator;
   StringStream stream(&string_allocator);
   shared->SourceCodePrint(&stream, -1);
   PrintF("[source:\n%s\n]", *stream.ToCString());
 
-  UNREACHABLE();
+  FATAL("unable to find pc offset during deoptimization");
   return -1;
 }
 
 
 int Deoptimizer::GetDeoptimizedCodeCount(Isolate* isolate) {
   int length = 0;
   DeoptimizingCodeListNode* node =
       isolate->deoptimizer_data()->deoptimizing_code_list_;
   while (node != NULL) {
     length++;
@@ skipping 1473 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