Changeset 48403 in webkit for trunk/JavaScriptCore/runtime/Structure.cpp

Timestamp:

Sep 15, 2009, 4:17:19 PM (16 years ago)

Author:

[email protected]

Message:

Allow anonymous storage inside JSObject
​https://bugs.webkit.org/show_bug.cgi?id=29168

Reviewed by Geoff Garen

Add the concept of anonymous slots to Structures so that it is
possible to store references to values that need marking in the
standard JSObject storage buffer. This allows us to reduce the
malloc overhead of some objects (by allowing them to store JS
values in the inline storage of the object) and reduce the
dependence of custom mark functions (if all an objects children
are in the standard object property storage there's no need to
mark them manually).

File:

• trunk/JavaScriptCore/runtime/Structure.cpp (modified) (7 diffs)

trunk/JavaScriptCore/runtime/Structure.cpp

@@ -153 +153 @@
 Structure::~Structure()
 {
-    if (m_previous)
-        m_previous->table.remove(make_pair(m_nameInPrevious.get(), m_attributesInPrevious), m_specificValueInPrevious);
+    if (m_previous) {
+        if (m_nameInPrevious)
+            m_previous->table.remove(make_pair(m_nameInPrevious.get(), m_attributesInPrevious), m_specificValueInPrevious);
+        else
+            m_previous->table.removeAnonymousSlotTransition(m_anonymousSlotsInPrevious);
+
+    }
 
     if (m_cachedPropertyNameArrayData)
@@ -268 +273 @@
     for (ptrdiff_t i = structures.size() - 2; i >= 0; --i) {
         structure = structures[i];
+        if (!structure->m_nameInPrevious) {
+            m_propertyTable->anonymousSlotCount += structure->m_anonymousSlotsInPrevious;
+            continue;
+        }
         structure->m_nameInPrevious->ref();
         PropertyMapEntry entry(structure->m_nameInPrevious.get(), structure->m_offset, structure->m_attributesInPrevious, structure->m_specificValueInPrevious, ++m_propertyTable->lastIndexUsed);
@@ -490 +499 @@
 }
 
+PassRefPtr<Structure> Structure::addAnonymousSlotsTransition(Structure* structure, unsigned count)
+{
+    if (Structure* transition = structure->table.getAnonymousSlotTransition(count)) {
+        ASSERT(transition->storedPrototype() == structure->storedPrototype());
+        return transition;
+    }
+    ASSERT(count);
+    ASSERT(count < ((1<<6) - 2));
+    RefPtr<Structure> transition = create(structure->m_prototype, structure->typeInfo());
+    
+    transition->m_cachedPrototypeChain = structure->m_cachedPrototypeChain;
+    transition->m_previous = structure;
+    transition->m_nameInPrevious = 0;
+    transition->m_attributesInPrevious = 0;
+    transition->m_anonymousSlotsInPrevious = count;
+    transition->m_specificValueInPrevious = 0;
+    transition->m_propertyStorageCapacity = structure->m_propertyStorageCapacity;
+    transition->m_hasGetterSetterProperties = structure->m_hasGetterSetterProperties;
+
+    if (structure->m_propertyTable) {
+        if (structure->m_isPinnedPropertyTable)
+            transition->m_propertyTable = structure->copyPropertyTable();
+        else {
+            transition->m_propertyTable = structure->m_propertyTable;
+            structure->m_propertyTable = 0;
+        }
+    } else {
+        if (structure->m_previous)
+            transition->materializePropertyMap();
+        else
+            transition->createPropertyMapHashTable();
+    }
+
+    transition->addAnonymousSlots(count);
+    if (transition->propertyStorageSize() > transition->propertyStorageCapacity())
+        transition->growPropertyStorageCapacity();
+
+    structure->table.addAnonymousSlotTransition(count, transition.get());
+    return transition.release();    
+}
+
 PassRefPtr<Structure> Structure::getterSetterTransition(Structure* structure)
 {
@@ -614 +664 @@
         newTable->deletedOffsets = new Vector<unsigned>(*m_propertyTable->deletedOffsets);
 
+    newTable->anonymousSlotCount = m_propertyTable->anonymousSlotCount;
     return newTable;
 }
@@ -793 +844 @@
         m_propertyTable->deletedOffsets->removeLast();
     } else
-        newOffset = m_propertyTable->keyCount;
+        newOffset = m_propertyTable->keyCount + m_propertyTable->anonymousSlotCount;
     m_propertyTable->entries()[entryIndex - 1].offset = newOffset;
 
@@ -803 +854 @@
     checkConsistency();
     return newOffset;
+}
+
+void Structure::addAnonymousSlots(unsigned count)
+{
+    m_propertyTable->anonymousSlotCount += count;
 }
 
@@ -963 +1019 @@
     m_propertyTable->size = newTableSize;
     m_propertyTable->sizeMask = newTableSize - 1;
+    m_propertyTable->anonymousSlotCount = oldTable->anonymousSlotCount;
 
     unsigned lastIndexUsed = 0;