Remove the patching of the debug break stub...

src/debug.cc

 // Copyright 2006-2008 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 1446 matching lines @@
 bool Debug::IsSourceBreakStub(Code* code) {
   CodeStub::Major major_key = CodeStub::GetMajorKey(code);
   return major_key == CodeStub::CallFunction;
 }
 
 
 // Check whether a code stub with the specified major key is a possible break
 // location.
 bool Debug::IsBreakStub(Code* code) {
   CodeStub::Major major_key = CodeStub::GetMajorKey(code);
-  return major_key == CodeStub::CallFunction ||
-         major_key == CodeStub::StackCheck;
+  return major_key == CodeStub::CallFunction;
 }
 
 
 // Find the builtin to use for invoking the debug break
 Handle<Code> Debug::FindDebugBreak(Handle<Code> code, RelocInfo::Mode mode) {
   // Find the builtin debug break function matching the calling convention
   // used by the call site.
   if (code->is_inline_cache_stub()) {
     switch (code->kind()) {
       case Code::CALL_IC:
@@ skipping 17 matching lines @@
       default:
         UNREACHABLE();
     }
   }
   if (RelocInfo::IsConstructCall(mode)) {
     Handle<Code> result =
         Handle<Code>(Builtins::builtin(Builtins::ConstructCall_DebugBreak));
     return result;
   }
   if (code->kind() == Code::STUB) {
-    ASSERT(code->major_key() == CodeStub::CallFunction ||
-           code->major_key() == CodeStub::StackCheck);
+    ASSERT(code->major_key() == CodeStub::CallFunction);
     Handle<Code> result =
         Handle<Code>(Builtins::builtin(Builtins::StubNoRegisters_DebugBreak));
     return result;
   }
 
   UNREACHABLE();
   return Handle<Code>::null();
 }
 
 
@@ skipping 1544 matching lines @@
     {
       Locker locker;
       Debugger::CallMessageDispatchHandler();
     }
   }
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal