Avoid checking for WTFThreadData::staticData in wtfThreadData()

third_party/WebKit/Source/wtf/WTFThreadData.h

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 37 matching lines @@
  public:
   WTFThreadData();
   ~WTFThreadData();
 
   AtomicStringTable& getAtomicStringTable() { return *m_atomicStringTable; }
 
   ICUConverterWrapper& cachedConverterICU() { return *m_cachedConverterICU; }
 
   ThreadIdentifier threadId() const { return m_threadId; }
 
+  static void initializeOnOffThread();
+  static void initializeOnMainThread();
+
 #if OS(WIN) && COMPILER(MSVC)
   static size_t threadStackSize();
 #endif
 
  private:
   std::unique_ptr<AtomicStringTable> m_atomicStringTable;
   std::unique_ptr<ICUConverterWrapper> m_cachedConverterICU;
 
   ThreadIdentifier m_threadId;
 
 #if OS(WIN) && COMPILER(MSVC)
   size_t m_threadStackSize = 0u;
 #endif
 
   static ThreadSpecific<WTFThreadData>* staticData;
   friend WTFThreadData& wtfThreadData();
 };
 
+// Special case WTFThreadData so accessors don't need to branch.
+template <>
+inline ThreadSpecific<WTFThreadData>::operator WTFThreadData*() {
+  DCHECK(isSet());
+#if defined(__GLIBC__) || OS(ANDROID) || OS(FREEBSD)
+  return static_cast<WTFThreadData*>(get());
+#else
+  if (UNLIKELY(internal::mayNotBeMainThread()))
+    return static_cast<WTFThreadData*>(get());
+  return m_mainThreadStorage;
+#endif
+}
+
+template <>
+inline void ThreadSpecific<WTFThreadData>::initializeOnOffThread() {
+  WTFThreadData* ptr = static_cast<WTFThreadData*>(Partitions::fastZeroedMalloc(
+      sizeof(WTFThreadData), WTF_HEAP_PROFILER_TYPE_NAME(WTFThreadData)));
+  set(ptr);
+  new (NotNull, ptr) WTFThreadData;
+}
+
+template <>
+inline void ThreadSpecific<WTFThreadData>::initializeOnMainThread() {
+  m_mainThreadStorage =
+      static_cast<WTFThreadData*>(Partitions::fastZeroedMalloc(
+          sizeof(WTFThreadData), WTF_HEAP_PROFILER_TYPE_NAME(WTFThreadData)));
+  set(m_mainThreadStorage);
+  new (NotNull, m_mainThreadStorage) WTFThreadData;
+}
+
 inline WTFThreadData& wtfThreadData() {
-  // WTFThreadData is used on main thread before it could possibly be used
-  // on secondary ones, so there is no need for synchronization here.
-  if (!WTFThreadData::staticData)
-    WTFThreadData::staticData = new ThreadSpecific<WTFThreadData>;
   return **WTFThreadData::staticData;
 }
 
 }  // namespace WTF
 
 using WTF::WTFThreadData;
 using WTF::wtfThreadData;
 
 #endif  // WTFThreadData_h