1 files changed, 10 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/runtime/JSString.h b/Source/JavaScriptCore/runtime/JSString.h
index 10ec799e5..c95233deb 100644
--- a/Source/JavaScriptCore/runtime/JSString.h
+++ b/Source/JavaScriptCore/runtime/JSString.h
@@ -67,6 +67,7 @@ namespace JSC {
         friend class JSGlobalData;
         friend class SpecializedThunkJIT;
         friend class JSRopeString;
+        friend class MarkStack;
         friend struct ThunkHelpers;
 
         typedef JSCell Base;
@@ -91,6 +92,7 @@ namespace JSC {
             Base::finishCreation(globalData);
             m_length = length;
             m_is8Bit = m_value.impl()->is8Bit();
+            m_isHashConstSingleton = false;
         }
 
         void finishCreation(JSGlobalData& globalData, size_t length, size_t cost)
@@ -99,6 +101,7 @@ namespace JSC {
             Base::finishCreation(globalData);
             m_length = length;
             m_is8Bit = m_value.impl()->is8Bit();
+            m_isHashConstSingleton = false;
             Heap::heap(this)->reportExtraMemoryCost(cost);
         }
 
@@ -108,6 +111,7 @@ namespace JSC {
             Base::finishCreation(globalData);
             m_length = 0;
             m_is8Bit = true;
+            m_isHashConstSingleton = false;
         }
         
     public:
@@ -161,9 +165,13 @@ namespace JSC {
     protected:
         bool isRope() const { return m_value.isNull(); }
         bool is8Bit() const { return m_is8Bit; }
+        bool isHashConstSingleton() const { return m_isHashConstSingleton; }
+        void clearHashConstSingleton() { m_isHashConstSingleton = false; }
+        void setHashConstSingleton() { m_isHashConstSingleton = true; }
 
         // A string is represented either by a UString or a rope of fibers.
         bool m_is8Bit : 1;
+        bool m_isHashConstSingleton : 1;
         unsigned m_length;
         mutable UString m_value;
 
@@ -233,6 +241,7 @@ namespace JSC {
             Base::finishCreation(globalData);
             m_length = s1->length() + s2->length();
             m_is8Bit = (s1->is8Bit() && s2->is8Bit());
+            m_isHashConstSingleton = false;
             m_fibers[0].set(globalData, this, s1);
             m_fibers[1].set(globalData, this, s2);
         }
@@ -242,6 +251,7 @@ namespace JSC {
             Base::finishCreation(globalData);
             m_length = s1->length() + s2->length() + s3->length();
             m_is8Bit = (s1->is8Bit() && s2->is8Bit() &&  s3->is8Bit());
+            m_isHashConstSingleton = false;
             m_fibers[0].set(globalData, this, s1);
             m_fibers[1].set(globalData, this, s2);
             m_fibers[2].set(globalData, this, s3);