1 files changed, 150 insertions, 9 deletions

diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/runtime/StructureTransitionTable.h b/src/3rdparty/javascriptcore/JavaScriptCore/runtime/StructureTransitionTable.h
index 804cbeb1de..0fa7b73c59 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/runtime/StructureTransitionTable.h
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/runtime/StructureTransitionTable.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008 Apple Inc. All rights reserved.
+ * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -30,6 +30,8 @@
 #include <wtf/HashFunctions.h>
 #include <wtf/HashMap.h>
 #include <wtf/HashTraits.h>
+#include <wtf/PtrAndFlags.h>
+#include <wtf/OwnPtr.h>
 #include <wtf/RefPtr.h>
 
 namespace JSC {
@@ -37,7 +39,7 @@ namespace JSC {
     class Structure;
 
     struct StructureTransitionTableHash {
-        typedef std::pair<RefPtr<UString::Rep>, std::pair<unsigned, JSCell*> > Key;
+        typedef std::pair<RefPtr<UString::Rep>, unsigned> Key;
         static unsigned hash(const Key& p)
         {
             return p.first->computedHash();
@@ -53,20 +55,159 @@ namespace JSC {
 
     struct StructureTransitionTableHashTraits {
         typedef WTF::HashTraits<RefPtr<UString::Rep> > FirstTraits;
-        typedef WTF::GenericHashTraits<unsigned> SecondFirstTraits;
-        typedef WTF::GenericHashTraits<JSCell*> SecondSecondTraits;
-        typedef std::pair<FirstTraits::TraitType, std::pair<SecondFirstTraits::TraitType, SecondSecondTraits::TraitType> > TraitType;
+        typedef WTF::GenericHashTraits<unsigned> SecondTraits;
+        typedef std::pair<FirstTraits::TraitType, SecondTraits::TraitType > TraitType;
 
-        static const bool emptyValueIsZero = FirstTraits::emptyValueIsZero && SecondFirstTraits::emptyValueIsZero && SecondSecondTraits::emptyValueIsZero;
-        static TraitType emptyValue() { return std::make_pair(FirstTraits::emptyValue(), std::make_pair(SecondFirstTraits::emptyValue(), SecondSecondTraits::emptyValue())); }
+        static const bool emptyValueIsZero = FirstTraits::emptyValueIsZero && SecondTraits::emptyValueIsZero;
+        static TraitType emptyValue() { return std::make_pair(FirstTraits::emptyValue(), SecondTraits::emptyValue()); }
 
-        static const bool needsDestruction = FirstTraits::needsDestruction || SecondFirstTraits::needsDestruction || SecondSecondTraits::needsDestruction;
+        static const bool needsDestruction = FirstTraits::needsDestruction || SecondTraits::needsDestruction;
 
         static void constructDeletedValue(TraitType& slot) { FirstTraits::constructDeletedValue(slot.first); }
         static bool isDeletedValue(const TraitType& value) { return FirstTraits::isDeletedValue(value.first); }
     };
 
-    typedef HashMap<StructureTransitionTableHash::Key, Structure*, StructureTransitionTableHash, StructureTransitionTableHashTraits> StructureTransitionTable;
+    class StructureTransitionTable {
+        typedef std::pair<Structure*, Structure*> Transition;
+        struct TransitionTable : public HashMap<StructureTransitionTableHash::Key, Transition, StructureTransitionTableHash, StructureTransitionTableHashTraits> {
+            typedef HashMap<unsigned, Structure*> AnonymousSlotMap;
+
+            void addSlotTransition(unsigned count, Structure* structure)
+            {
+                ASSERT(!getSlotTransition(count));
+                if (!m_anonymousSlotTable)
+                    m_anonymousSlotTable.set(new AnonymousSlotMap);
+                m_anonymousSlotTable->add(count, structure);
+            }
+
+            void removeSlotTransition(unsigned count)
+            {
+                ASSERT(getSlotTransition(count));
+                m_anonymousSlotTable->remove(count);
+            }
+
+            Structure* getSlotTransition(unsigned count)
+            {
+                if (!m_anonymousSlotTable)
+                    return 0;
+
+                AnonymousSlotMap::iterator find = m_anonymousSlotTable->find(count);
+                if (find == m_anonymousSlotTable->end())
+                    return 0;
+                return find->second;
+            }
+        private:
+            OwnPtr<AnonymousSlotMap> m_anonymousSlotTable;
+        };
+    public:
+        StructureTransitionTable() {
+            m_transitions.m_singleTransition.set(0);
+            m_transitions.m_singleTransition.setFlag(usingSingleSlot);
+        }
+
+        ~StructureTransitionTable() {
+            if (!usingSingleTransitionSlot())
+                delete table();
+        }
+
+        // The contains and get methods accept imprecise matches, so if an unspecialised transition exists
+        // for the given key they will consider that transition to be a match.  If a specialised transition
+        // exists and it matches the provided specificValue, get will return the specific transition.
+        inline bool contains(const StructureTransitionTableHash::Key&, JSCell* specificValue);
+        inline Structure* get(const StructureTransitionTableHash::Key&, JSCell* specificValue) const;
+        inline bool hasTransition(const StructureTransitionTableHash::Key& key) const;
+        void remove(const StructureTransitionTableHash::Key& key, JSCell* specificValue)
+        {
+            if (usingSingleTransitionSlot()) {
+                ASSERT(contains(key, specificValue));
+                setSingleTransition(0);
+                return;
+            }
+            TransitionTable::iterator find = table()->find(key);
+            if (!specificValue)
+                find->second.first = 0;
+            else
+                find->second.second = 0;
+            if (!find->second.first && !find->second.second)
+                table()->remove(find);
+        }
+        void add(const StructureTransitionTableHash::Key& key, Structure* structure, JSCell* specificValue)
+        {
+            if (usingSingleTransitionSlot()) {
+                if (!singleTransition()) {
+                    setSingleTransition(structure);
+                    return;
+                }
+                reifySingleTransition();
+            }
+            if (!specificValue) {
+                TransitionTable::iterator find = table()->find(key);
+                if (find == table()->end())
+                    table()->add(key, Transition(structure, 0));
+                else
+                    find->second.first = structure;
+            } else {
+                // If we're adding a transition to a specific value, then there cannot be
+                // an existing transition
+                ASSERT(!table()->contains(key));
+                table()->add(key, Transition(0, structure));
+            }
+        }
+
+        Structure* getAnonymousSlotTransition(unsigned count)
+        {
+            if (usingSingleTransitionSlot())
+                return 0;
+            return table()->getSlotTransition(count);
+        }
+
+        void addAnonymousSlotTransition(unsigned count, Structure* structure)
+        {
+            if (usingSingleTransitionSlot())
+                reifySingleTransition();
+            ASSERT(!table()->getSlotTransition(count));
+            table()->addSlotTransition(count, structure);
+        }
+        
+        void removeAnonymousSlotTransition(unsigned count)
+        {
+            ASSERT(!usingSingleTransitionSlot());
+            table()->removeSlotTransition(count);
+        }
+    private:
+        TransitionTable* table() const { ASSERT(!usingSingleTransitionSlot()); return m_transitions.m_table; }
+        Structure* singleTransition() const {
+            ASSERT(usingSingleTransitionSlot());
+            return m_transitions.m_singleTransition.get();
+        }
+        bool usingSingleTransitionSlot() const { return m_transitions.m_singleTransition.isFlagSet(usingSingleSlot); }
+        void setSingleTransition(Structure* structure)
+        { 
+            ASSERT(usingSingleTransitionSlot());
+            m_transitions.m_singleTransition.set(structure);
+        }
+
+        void setTransitionTable(TransitionTable* table)
+        {
+            ASSERT(usingSingleTransitionSlot());
+#ifndef NDEBUG
+            setSingleTransition(0);
+#endif
+            m_transitions.m_table = table;
+            // This implicitly clears the flag that indicates we're using a single transition
+            ASSERT(!usingSingleTransitionSlot());
+        }
+        inline void reifySingleTransition();
+
+        enum UsingSingleSlot {
+            usingSingleSlot
+        };
+        // Last bit indicates whether we are using the single transition optimisation
+        union {
+            TransitionTable* m_table;
+            PtrAndFlagsBase<Structure, UsingSingleSlot> m_singleTransition;
+        } m_transitions;
+    };
 
 } // namespace JSC