Changeset 100242 in webkit

Timestamp:

Nov 14, 2011, 10:58:19 PM (15 years ago)

Author:

fpizlo@apple.com

Message:

Weak reference harvesters should run to fixpoint
​https://bugs.webkit.org/show_bug.cgi?id=72346

Reviewed by Oliver Hunt.

• heap/Heap.cpp:

(JSC::Heap::markRoots):

• heap/ListableHandler.h:

(JSC::ListableHandler::next):
(JSC::ListableHandler::List::head):
(JSC::ListableHandler::List::removeNext):
(JSC::ListableHandler::List::removeAll):

• heap/MarkStack.cpp:

(JSC::MarkStackThreadSharedData::reset):
(JSC::SlotVisitor::harvestWeakReferences):

• heap/MarkStack.h:

(JSC::MarkStack::isEmpty):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• heap/Heap.cpp (modified) (2 diffs)
• heap/ListableHandler.h (modified) (2 diffs)
• heap/MarkStack.cpp (modified) (2 diffs)
• heap/MarkStack.h (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2011-11-14  Filip Pizlo  <fpizlo@apple.com>
+
+        Weak reference harvesters should run to fixpoint
+        https://bugs.webkit.org/show_bug.cgi?id=72346
+
+        Reviewed by Oliver Hunt.
+
+        * heap/Heap.cpp:
+        (JSC::Heap::markRoots):
+        * heap/ListableHandler.h:
+        (JSC::ListableHandler::next):
+        (JSC::ListableHandler::List::head):
+        (JSC::ListableHandler::List::removeNext):
+        (JSC::ListableHandler::List::removeAll):
+        * heap/MarkStack.cpp:
+        (JSC::MarkStackThreadSharedData::reset):
+        (JSC::SlotVisitor::harvestWeakReferences):
+        * heap/MarkStack.h:
+        (JSC::MarkStack::isEmpty):
+
 2011-11-14  Oliver Hunt  <oliver@apple.com>
 

trunk/Source/JavaScriptCore/heap/Heap.cpp

@@ -685 +685 @@
     {
         GCPHASE(VisitingWeakHandles);
-        int lastOpaqueRootCount;
-        do {
-            lastOpaqueRootCount = visitor.opaqueRootCount();
+        while (true) {
             m_handleHeap.visitWeakHandles(heapRootVisitor);
+            harvestWeakReferences();
+            if (visitor.isEmpty())
+                break;
             {
                 ParallelModeEnabler enabler(visitor);
@@ -696 +697 @@
 #endif
             }
-            // If the set of opaque roots has grown, more weak handles may have become reachable.
-        } while (lastOpaqueRootCount != visitor.opaqueRootCount());
+        }
     }
     GCCOUNTER(VisitedValueCount, visitor.visitCount());
-
-    {
-        GCPHASE(HarvestWeakReferences);
-        harvestWeakReferences();
-    }
 
     visitor.reset();

trunk/Source/JavaScriptCore/heap/ListableHandler.h

@@ -43 +43 @@
     
     virtual ~ListableHandler() { }
+    
+    T* next() const
+    {
+        return reinterpret_cast<T*>(m_nextAndFlag & ~1);
+    }
 
 private:
@@ -73 +78 @@
         }
         
+        T* head()
+        {
+            return m_first;
+        }
+        
         T* removeNext()
         {
             T* current = m_first;
-            T* next = reinterpret_cast<T*>(current->m_nextAndFlag & ~1);
+            T* next = current->next();
             current->m_nextAndFlag = 0;
             m_first = next;
             return current;
+        }
+        
+        void removeAll()
+        {
+            while (hasNext())
+                removeNext();
         }
         

trunk/Source/JavaScriptCore/heap/MarkStack.cpp

@@ -272 +272 @@
     ASSERT(m_opaqueRoots.isEmpty());
 #endif
+    
+    m_weakReferenceHarvesters.removeAll();
 }
 
@@ -450 +452 @@
 void SlotVisitor::harvestWeakReferences()
 {
-    while (m_shared.m_weakReferenceHarvesters.hasNext())
-        m_shared.m_weakReferenceHarvesters.removeNext()->visitWeakReferences(*this);
+    for (WeakReferenceHarvester* current = m_shared.m_weakReferenceHarvesters.head(); current; current = current->next())
+        current->visitWeakReferences(*this);
 }
 

trunk/Source/JavaScriptCore/heap/MarkStack.h

@@ -220 +220 @@
         bool containsOpaqueRoot(void*);
         int opaqueRootCount();
+        
+        bool isEmpty() { return m_stack.isEmpty(); }
 
         void reset();