Never clear debug-stub call ICs. Make a clear distinction between is_debug_stub

src/debug.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 1609 matching lines @@
 
   // No step next action - don't continue.
   return false;
 }
 
 
 // Check whether the code object at the specified address is a debug break code
 // object.
 bool Debug::IsDebugBreak(Address addr) {
   Code* code = Code::GetCodeFromTargetAddress(addr);
-  return code->is_debug_break();
+  return code->is_debug_stub() && code->extra_ic_state() == DEBUG_BREAK;
 }
 
 
 // Check whether a code stub with the specified major key is a possible break
 // point location when looking for source break locations.
 bool Debug::IsSourceBreakStub(Code* code) {
   CodeStub::Major major_key = CodeStub::GetMajorKey(code);
   return major_key == CodeStub::CallFunction;
 }
 
@@ skipping 2224 matching lines @@
     {
       Locker locker(reinterpret_cast<v8::Isolate*>(isolate_));
       isolate_->debugger()->CallMessageDispatchHandler();
     }
   }
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal