Added a special stack guard to deopt marked allocation sites.

src/objects.h

 // 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 8234 matching lines @@
 
   // This method is expensive, it should only be called for reporting.
   bool IsNestedSite();
 
   // transition_info bitfields, for constructed array transition info.
   class ElementsKindBits:       public BitField<ElementsKind, 0,  15> {};
   class UnusedBits:             public BitField<int,          15, 14> {};
   class DoNotInlineBit:         public BitField<bool,         29,  1> {};
 
   // Bitfields for pretenure_data
-  class MementoFoundCountBits:  public BitField<int,          0, 28> {};
-  class PretenureDecisionBits:  public BitField<PretenureDecision, 28, 2> {};
+  class MementoFoundCountBits:  public BitField<int,               0, 27> {};
+  class PretenureDecisionBits:  public BitField<PretenureDecision, 27, 2> {};
+  class DeoptDependentCodeBit:  public BitField<bool,              29, 1> {};
   STATIC_ASSERT(PretenureDecisionBits::kMax >= kLastPretenureDecisionValue);
 
   // Increments the mementos found counter and returns true when the first
   // memento was found for a given allocation site.
   inline bool IncrementMementoFoundCount();
 
   inline void IncrementMementoCreateCount();
 
   PretenureFlag GetPretenureMode();
 
   void ResetPretenureDecision();
 
   PretenureDecision pretenure_decision() {
     int value = pretenure_data()->value();
     return PretenureDecisionBits::decode(value);
   }
 
   void set_pretenure_decision(PretenureDecision decision) {
     int value = pretenure_data()->value();
     set_pretenure_data(
         Smi::FromInt(PretenureDecisionBits::update(value, decision)),
         SKIP_WRITE_BARRIER);
   }
 
+  bool deopt_dependent_code() {
+    int value = pretenure_data()->value();
+    return DeoptDependentCodeBit::decode(value);
+  }
+
+  void set_deopt_dependent_code(bool deopt) {
+    int value = pretenure_data()->value();
+    set_pretenure_data(
+        Smi::FromInt(DeoptDependentCodeBit::update(value, deopt)),
+        SKIP_WRITE_BARRIER);
+  }
+
   int memento_found_count() {
     int value = pretenure_data()->value();
     return MementoFoundCountBits::decode(value);
   }
 
   inline void set_memento_found_count(int count);
 
   int memento_create_count() {
     return pretenure_create_count()->value();
   }
@@ skipping 2462 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_