Added a special stack guard to deopt marked allocation sites.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 62251fb32dbed76a7d3f7e510a41c94be01b5179..4b5462dc3985e72c44d8c5dd1b850ad408173db1 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -8252,8 +8252,9 @@ class AllocationSite: public Struct {
   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
@@ -8278,6 +8279,18 @@ class AllocationSite: public Struct {
         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);