diff -r 3bdbc1d2a0a3 JavaScriptCore/runtime/JSString.h
--- a/JavaScriptCore/runtime/JSString.h	Tue Mar 23 16:41:06 2010 +0800
+++ b/JavaScriptCore/runtime/JSString.h	Tue Mar 23 18:49:11 2010 +0800
@@ -139,7 +139,7 @@
             , m_length(rope->length())
             , m_fiberCount(1)
         {
-            m_other.m_fibers[0] = rope.releaseRef();
+            m_other.m_union.m_fibers[0] = rope.releaseRef();
         }
         // This constructor constructs a new string by concatenating s1 & s2.
         // This should only be called with fiberCount <= 3.
@@ -203,8 +203,8 @@
             , m_fiberCount(0)
         {
             // nasty hack because we can't union non-POD types
-            m_other.m_finalizerCallback = finalizer;
-            m_other.m_finalizerContext = context;
+            m_other.m_union.m_struct.m_finalizerCallback = finalizer;
+            m_other.m_union.m_struct.m_finalizerContext = context;
             Heap::heap(this)->reportExtraMemoryCost(value.cost());
         }
 
@@ -212,10 +212,10 @@
         {
             ASSERT(vptr() == JSGlobalData::jsStringVPtr);
             for (unsigned i = 0; i < m_fiberCount; ++i)
-                m_other.m_fibers[i]->deref();
+                m_other.m_union.m_fibers[i]->deref();
 
-            if (!m_fiberCount && m_other.m_finalizerCallback)
-                m_other.m_finalizerCallback(this, m_other.m_finalizerContext);
+            if (!m_fiberCount && m_other.m_union.m_struct.m_finalizerCallback)
+                m_other.m_union.m_struct.m_finalizerCallback(this, m_other.m_union.m_struct.m_finalizerContext);
         }
 
         const UString& value(ExecState* exec) const
@@ -256,16 +256,16 @@
         {
             UStringImpl* impl = string.rep();
             impl->ref();
-            m_other.m_fibers[index++] = impl;
+            m_other.m_union.m_fibers[index++] = impl;
         }
 
         void appendStringInConstruct(unsigned& index, JSString* jsString)
         {
             if (jsString->isRope()) {
                 for (unsigned i = 0; i < jsString->m_fiberCount; ++i) {
-                    Rope::Fiber fiber = jsString->m_other.m_fibers[i];
+                    Rope::Fiber fiber = jsString->m_other.m_union.m_fibers[i];
                     fiber->ref();
-                    m_other.m_fibers[index++] = fiber;
+                    m_other.m_union.m_fibers[index++] = fiber;
                 }
             } else
                 appendStringInConstruct(index, jsString->string());
@@ -283,7 +283,7 @@
                 UString u(v.toString(exec));
                 UStringImpl* impl = u.rep();
                 impl->ref();
-                m_other.m_fibers[index++] = impl;
+                m_other.m_union.m_fibers[index++] = impl;
                 m_length += u.size();
             }
         }
@@ -312,14 +312,14 @@
         mutable unsigned m_fiberCount;
         // This structure exists to support a temporary workaround for a GC issue.
         struct JSStringFinalizerStruct {
-            JSStringFinalizerStruct() : m_finalizerCallback(0) {}
+            //JSStringFinalizerStruct() : JSStringFinalizerStructUnion::JSStringFinalizerStructInner::m_finalizerCallback(0) {}
             union {
                 mutable Rope::Fiber m_fibers[s_maxInternalRopeLength];
                 struct {
                     JSStringFinalizerCallback m_finalizerCallback;
                     void* m_finalizerContext;
-                };
-            };
+                } m_struct;
+            } m_union;
         } m_other;
 
         bool isRope() const { return m_fiberCount; }
diff -r d743efab4cb5 JavaScriptCore/runtime/JSString.cpp
--- a/JavaScriptCore/runtime/JSString.cpp	Wed Mar 24 18:16:39 2010 +0800
+++ b/JavaScriptCore/runtime/JSString.cpp	Wed Mar 24 20:26:23 2010 +0800
@@ -51,8 +51,8 @@
         m_value = newImpl;
     else {
         for (unsigned i = 0; i < m_fiberCount; ++i) {
-            m_other.m_fibers[i]->deref();
-            m_other.m_fibers[i] = 0;
+            m_other.m_union.m_fibers[i]->deref();
+            m_other.m_union.m_fibers[i] = 0;
         }
         m_fiberCount = 0;
         ASSERT(!isRope());
@@ -66,8 +66,8 @@
     Vector<Rope::Fiber, 32> workQueue;
     Rope::Fiber currentFiber;
     for (unsigned i = 0; i < (m_fiberCount - 1); ++i)
-        workQueue.append(m_other.m_fibers[i]);
-    currentFiber = m_other.m_fibers[m_fiberCount - 1];
+        workQueue.append(m_other.m_union.m_fibers[i]);
+    currentFiber = m_other.m_union.m_fibers[m_fiberCount - 1];
     while (true) {
         if (currentFiber->isRope()) {
             Rope* rope = static_cast<URopeImpl*>(currentFiber);
@@ -88,8 +88,8 @@
                 // Create a string from the UChar buffer, clear the rope RefPtr.
                 ASSERT(buffer == position);
                 for (unsigned i = 0; i < m_fiberCount; ++i) {
-                    m_other.m_fibers[i]->deref();
-                    m_other.m_fibers[i] = 0;
+                    m_other.m_union.m_fibers[i]->deref();
+                    m_other.m_union.m_fibers[i] = 0;
                 }
                 m_fiberCount = 0;
 
diff -r d2a07bdc6744 JavaScriptCore/runtime/JSString.h
--- a/JavaScriptCore/runtime/JSString.h	Tue May 18 19:09:56 2010 +0800
+++ b/JavaScriptCore/runtime/JSString.h	Tue May 18 20:11:12 2010 +0800
@@ -92,7 +92,7 @@
             {
                 if (jsString->isRope()) {
                     for (unsigned i = 0; i < jsString->m_fiberCount; ++i)
-                        append(jsString->m_other.m_fibers[i]);
+                        append(jsString->m_other.m_union.m_fibers[i]);
                 } else
                     append(jsString->string());
             }