1 files changed, 47 insertions, 21 deletions

diff --git a/src/qml/jsruntime/qv4persistent.cpp b/src/qml/jsruntime/qv4persistent.cpp
index 0b31c971f9..79c372348f 100644
--- a/src/qml/jsruntime/qv4persistent.cpp
+++ b/src/qml/jsruntime/qv4persistent.cpp
@@ -68,6 +68,22 @@ Page *getPage(Value *val) {
    return reinterpret_cast<Page *>(reinterpret_cast<quintptr>(val) & ~((quintptr)(WTF::pageSize() - 1)));
 }
 
+QML_NEARLY_ALWAYS_INLINE void insertInFront(PersistentValueStorage *storage, Page *p)
+{
+    p->header.next = reinterpret_cast<Page *>(storage->firstPage);
+    p->header.prev = reinterpret_cast<Page **>(&storage->firstPage);
+    if (p->header.next)
+        p->header.next->header.prev = &p->header.next;
+    storage->firstPage = p;
+}
+
+QML_NEARLY_ALWAYS_INLINE void unlink(Page *p)
+{
+    if (p->header.prev)
+        *p->header.prev = p->header.next;
+    if (p->header.next)
+        p->header.next->header.prev = p->header.prev;
+}
 
 Page *allocatePage(PersistentValueStorage *storage)
 {
@@ -78,18 +94,13 @@ Page *allocatePage(PersistentValueStorage *storage)
 
     p->header.engine = storage->engine;
     p->header.alloc = page;
-    p->header.next = reinterpret_cast<Page *>(storage->firstPage);
-    p->header.prev = reinterpret_cast<Page **>(&storage->firstPage);
     p->header.refCount = 0;
     p->header.freeList = 0;
-    if (p->header.next)
-        p->header.next->header.prev = &p->header.next;
+    insertInFront(storage, p);
     for (int i = 0; i < kEntriesPerPage - 1; ++i) {
-        p->values[i].setEmpty(i + 1);
+        p->values[i] = Encode(i + 1);
     }
-    p->values[kEntriesPerPage - 1].setEmpty(-1);
-
-    storage->firstPage = p;
+    p->values[kEntriesPerPage - 1] = Encode(-1);
 
     return p;
 }
@@ -161,7 +172,7 @@ Value &PersistentValueStorage::Iterator::operator *()
 
 PersistentValueStorage::PersistentValueStorage(ExecutionEngine *engine)
     : engine(engine),
-      firstPage(0)
+      firstPage(nullptr)
 {
 }
 
@@ -174,9 +185,9 @@ PersistentValueStorage::~PersistentValueStorage()
                 p->values[i] = Encode::undefined();
         }
         Page *n = p->header.next;
-        p->header.engine = 0;
-        p->header.prev = 0;
-        p->header.next = 0;
+        p->header.engine = nullptr;
+        p->header.prev = nullptr;
+        p->header.next = nullptr;
         Q_ASSERT(p->header.refCount);
         p = n;
     }
@@ -195,6 +206,12 @@ Value *PersistentValueStorage::allocate()
 
     Value *v = p->values + p->header.freeList;
     p->header.freeList = v->int_32();
+
+    if (p->header.freeList != -1 && p != firstPage) {
+        unlink(p);
+        insertInFront(this, p);
+    }
+
     ++p->header.refCount;
 
     v->setRawValue(Encode::undefined());
@@ -209,7 +226,7 @@ void PersistentValueStorage::free(Value *v)
 
     Page *p = getPage(v);
 
-    v->setEmpty(p->header.freeList);
+    *v = Encode(p->header.freeList);
     p->header.freeList = v - p->values;
     if (!--p->header.refCount)
         freePage(p);
@@ -237,16 +254,13 @@ ExecutionEngine *PersistentValueStorage::getEngine(Value *v)
 void PersistentValueStorage::freePage(void *page)
 {
     Page *p = static_cast<Page *>(page);
-    if (p->header.prev)
-        *p->header.prev = p->header.next;
-    if (p->header.next)
-        p->header.next->header.prev = p->header.prev;
+    unlink(p);
     p->header.alloc.deallocate();
 }
 
 
 PersistentValue::PersistentValue(const PersistentValue &other)
-    : val(0)
+    : val(nullptr)
 {
     if (other.val) {
         val = other.engine()->memoryManager->m_persistentValues->allocate();
@@ -267,7 +281,7 @@ PersistentValue::PersistentValue(ExecutionEngine *engine, ReturnedValue value)
 }
 
 PersistentValue::PersistentValue(ExecutionEngine *engine, Object *object)
-    : val(0)
+    : val(nullptr)
 {
     if (!object)
         return;
@@ -288,6 +302,10 @@ PersistentValue &PersistentValue::operator=(const PersistentValue &other)
             return *this;
         val = other.engine()->memoryManager->m_persistentValues->allocate();
     }
+    if (!other.val) {
+        *val = Encode::undefined();
+        return *this;
+    }
 
     Q_ASSERT(engine() == other.engine());
 
@@ -302,6 +320,10 @@ PersistentValue &PersistentValue::operator=(const WeakValue &other)
             return *this;
         val = other.engine()->memoryManager->m_persistentValues->allocate();
     }
+    if (!other.valueRef()) {
+        *val = Encode::undefined();
+        return *this;
+    }
 
     Q_ASSERT(engine() == other.engine());
 
@@ -344,7 +366,7 @@ void PersistentValue::set(ExecutionEngine *engine, Heap::Base *obj)
 }
 
 WeakValue::WeakValue(const WeakValue &other)
-    : val(0)
+    : val(nullptr)
 {
     if (other.val) {
         allocVal(other.engine());
@@ -365,6 +387,10 @@ WeakValue &WeakValue::operator=(const WeakValue &other)
             return *this;
         allocVal(other.engine());
     }
+    if (!other.val) {
+        *val = Encode::undefined();
+        return *this;
+    }
 
     Q_ASSERT(engine() == other.engine());
 
@@ -404,6 +430,6 @@ void WeakValue::free()
         PersistentValueStorage::free(val);
     }
 
-    val = 0;
+    val = nullptr;
 }