1 files changed, 47 insertions, 9 deletions

diff --git a/Source/JavaScriptCore/heap/MarkStack.cpp b/Source/JavaScriptCore/heap/MarkStack.cpp
index cf6e3513c..785444e55 100644
--- a/Source/JavaScriptCore/heap/MarkStack.cpp
+++ b/Source/JavaScriptCore/heap/MarkStack.cpp
@@ -36,6 +36,7 @@
 #include "JSObject.h"
 #include "ScopeChain.h"
 #include "Structure.h"
+#include "UString.h"
 #include "WriteBarrier.h"
 #include <wtf/MainThread.h>
 
@@ -218,17 +219,24 @@ void MarkStackArray::stealSomeCellsFrom(MarkStackArray& other)
 }
 
 #if ENABLE(PARALLEL_GC)
-void MarkStackThreadSharedData::markingThreadMain()
+void MarkStackThreadSharedData::resetChildren()
+{
+    for (unsigned i = 0; i < m_slaveMarkStacks.size(); ++i)
+       m_slaveMarkStacks[i]->reset();
+}
+
+void MarkStackThreadSharedData::markingThreadMain(SlotVisitor* slotVisitor)
 {
     WTF::registerGCThread();
-    SlotVisitor slotVisitor(*this);
-    ParallelModeEnabler enabler(slotVisitor);
-    slotVisitor.drainFromShared(SlotVisitor::SlaveDrain);
+    ParallelModeEnabler enabler(*slotVisitor);
+    slotVisitor->drainFromShared(SlotVisitor::SlaveDrain);
+    delete slotVisitor;
 }
 
-void MarkStackThreadSharedData::markingThreadStartFunc(void* shared)
+void MarkStackThreadSharedData::markingThreadStartFunc(void* myVisitor)
 {
-    static_cast<MarkStackThreadSharedData*>(shared)->markingThreadMain();
+    SlotVisitor* slotVisitor = static_cast<SlotVisitor*>(myVisitor);
+    slotVisitor->sharedData().markingThreadMain(slotVisitor);
 }
 #endif
 
@@ -241,7 +249,9 @@ MarkStackThreadSharedData::MarkStackThreadSharedData(JSGlobalData* globalData)
 {
 #if ENABLE(PARALLEL_GC)
     for (unsigned i = 1; i < Options::numberOfGCMarkers; ++i) {
-        m_markingThreads.append(createThread(markingThreadStartFunc, this, "JavaScriptCore::Marking"));
+        SlotVisitor* slotVisitor = new SlotVisitor(*this);
+        m_slaveMarkStacks.append(slotVisitor);
+        m_markingThreads.append(createThread(markingThreadStartFunc, slotVisitor, "JavaScriptCore::Marking"));
         ASSERT(m_markingThreads.last());
     }
 #endif
@@ -273,7 +283,6 @@ void MarkStackThreadSharedData::reset()
 #else
     ASSERT(m_opaqueRoots.isEmpty());
 #endif
-    
     m_weakReferenceHarvesters.removeAll();
 }
 
@@ -286,6 +295,7 @@ void MarkStack::reset()
 #else
     m_opaqueRoots.clear();
 #endif
+    m_uniqueStrings.clear();
 }
 
 void MarkStack::append(ConservativeRoots& conservativeRoots)
@@ -486,6 +496,34 @@ void* SlotVisitor::allocateNewSpace(void* ptr, size_t bytes)
     return CopiedSpace::allocateFromBlock(m_copyBlock, bytes);
 }
 
+inline void MarkStack::internalAppend(JSValue* slot)
+{
+    ASSERT(slot);
+    JSValue value = *slot;
+    ASSERT(value);
+    if (!value.isCell())
+        return;
+
+    if (value.isString()) {
+        JSString* string = jsCast<JSString*>(value.asCell());
+        if (!string->isHashConstSingleton() && string->length() > 1 && !string->isRope()) {
+            UniqueStringMap::AddResult addResult = m_uniqueStrings.add(string->string().impl(), value);
+            if (addResult.isNewEntry)
+                string->setHashConstSingleton();
+            else {
+                JSValue existingJSValue = addResult.iterator->second;
+                if (value != existingJSValue)
+                    jsCast<JSString*>(existingJSValue.asCell())->clearHashConstSingleton();
+                *slot = existingJSValue;
+                return;
+            }
+        }
+    }
+
+    internalAppend(value.asCell());
+}
+
+
 void SlotVisitor::copyAndAppend(void** ptr, size_t bytes, JSValue* values, unsigned length)
 {
     void* oldPtr = *ptr;
@@ -499,7 +537,7 @@ void SlotVisitor::copyAndAppend(void** ptr, size_t bytes, JSValue* values, unsig
             newValues[i] = value;
             if (!value)
                 continue;
-            internalAppend(value);
+            internalAppend(&newValues[i]);
         }
 
         memcpy(newPtr, oldPtr, jsValuesOffset);