1 files changed, 21 insertions, 0 deletions
diff --git a/src/qml/jsruntime/qv4identifier.cpp b/src/qml/jsruntime/qv4identifier.cpp
index 626648067f..6260fd0cc8 100644
--- a/src/qml/jsruntime/qv4identifier.cpp
+++ b/src/qml/jsruntime/qv4identifier.cpp
@@ -64,12 +64,33 @@ IdentifierHashData::IdentifierHashData(int numBits)
     memset(entries, 0, alloc*sizeof(IdentifierHashEntry));
 }
 
+IdentifierHashData::IdentifierHashData(IdentifierHashData *other)
+    : size(other->size)
+    , numBits(other->numBits)
+    , identifierTable(other->identifierTable)
+{
+    refCount.store(1);
+    alloc = other->alloc;
+    entries = (IdentifierHashEntry *)malloc(alloc*sizeof(IdentifierHashEntry));
+    memcpy(entries, other->entries, alloc*sizeof(IdentifierHashEntry));
+}
+
 IdentifierHashBase::IdentifierHashBase(ExecutionEngine *engine)
 {
     d = new IdentifierHashData(3);
     d->identifierTable = engine->identifierTable;
 }
 
+void IdentifierHashBase::detach()
+{
+    if (!d || d->refCount == 1)
+        return;
+    IdentifierHashData *newData = new IdentifierHashData(d);
+    if (d && !d->refCount.deref())
+        delete d;
+    d = newData;
+}
+
 
 IdentifierHashEntry *IdentifierHashBase::addEntry(const Identifier *identifier)
 {