Changeset 96372 in webkit for trunk/Source/JavaScriptCore/heap/Heap.cpp

Timestamp:

Sep 29, 2011, 3:52:45 PM (14 years ago)

Author:

[email protected]

Message:

Add logic to collect dirty objects as roots
​https://bugs.webkit.org/show_bug.cgi?id=69100

Reviewed by Geoff Garen.

This gives us the ability to walk all the MarkedBlocks in an
AllocationSpace and collect the dirty objects, and then use
them as GC roots.

• dfg/DFGJITCodeGenerator.cpp:

(JSC::DFG::JITCodeGenerator::markCellCard):

• dfg/DFGJITCodeGenerator32_64.cpp:

(JSC::DFG::JITCodeGenerator::markCellCard):

• heap/AllocationSpace.cpp:

Tidy up the write barrier logic a bit

(JSC::MarkedBlock::gatherDirtyObjects):
(JSC::TakeIfDirty::returnValue):
(JSC::TakeIfDirty::TakeIfDirty):
(JSC::TakeIfDirty::operator()):
(JSC::AllocationSpace::gatherDirtyObjects):

• heap/AllocationSpace.h:
• heap/CardSet.h:

(JSC::::isCardMarked):
(JSC::::clearCard):

• heap/Heap.cpp:

(JSC::Heap::markRoots):

• heap/Heap.h:

(JSC::Heap::writeBarrier):

• heap/MarkStack.cpp:

(JSC::SlotVisitor::visitChildren):

• heap/MarkedBlock.h:

(JSC::MarkedBlock::setDirtyObject):
(JSC::MarkedBlock::addressOfCardFor):

• heap/SlotVisitor.h:
• jit/JITPropertyAccess.cpp:

(JSC::JIT::emitWriteBarrier):

Tidy the write barrier a bit

File:

• trunk/Source/JavaScriptCore/heap/Heap.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/heap/Heap.cpp

@@ -472 +472 @@
     registerFile().gatherConservativeRoots(registerFileRoots, m_jettisonedCodeBlocks);
     m_jettisonedCodeBlocks.deleteUnmarkedCodeBlocks();
-
-    clearMarks();
+#if ENABLE(GGC)
+    MarkedBlock::DirtyCellVector dirtyCells;
+    // Until we have a sensible policy we just random choose to perform
+    // young generation collections 90% of the time.
+    if (WTF::randomNumber() > 0.1)
+        m_objectSpace.gatherDirtyCells(dirtyCells);
+    else
+#endif
+        clearMarks();
+
 
     SlotVisitor& visitor = m_slotVisitor;
     HeapRootVisitor heapRootVisitor(visitor);
-    
+
+#if ENABLE(GGC)
+    for (size_t i = 0; i < dirtyObjectCount; i++) {
+        heapRootVisitor.visitChildren(dirtyCells[i]);
+        visitor.drain();
+    }
+#endif
+
     visitor.append(machineThreadRoots);
     visitor.drain();