Use new ASAN APIs for scanning ASAN fake stacks during garbage collection.

Source/heap/ThreadState.h

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 408 matching lines @@
     // corresponding to a given address. Return 0 if the address is
     // not contained in any of the pages.
     BaseHeapPage* heapPageFromAddress(Address);
 
     // List of persistent roots allocated on the given thread.
     PersistentNode* roots() const { return m_persistents; }
 
     // Visit local thread stack and trace all pointers conservatively.
     void visitStack(Visitor*);
 
+#if defined(ADDRESS_SANITIZER) && !OS(WIN)
+    // Visit the asan fake stack frame corresponding to a slot on the
+    // real machine stack if there is one.
+    void visitAsanFakeStackForPointer(Visitor*, Address);
+#endif
+
     // Visit all persistents allocated on this thread.
     void visitPersistents(Visitor*);
 
     // Checks a given address and if a pointer into the oilpan heap marks
     // the object to which it points.
     bool checkAndMarkPointer(Visitor*, Address);
 
     void getStats(HeapStats&);
     HeapStats& stats() { return m_stats; }
     HeapStats& statsAfterLastGC() { return m_statsAfterLastGC; }
@@ skipping 41 matching lines @@
     Vector<Interruptor*> m_interruptors;
     bool m_gcRequested;
     volatile int m_sweepRequested;
     bool m_sweepInProgress;
     size_t m_noAllocationCount;
     bool m_inGC;
     BaseHeap* m_heaps[NumberOfHeaps];
     HeapContainsCache* m_heapContainsCache;
     HeapStats m_stats;
     HeapStats m_statsAfterLastGC;
+#if defined(ADDRESS_SANITIZER) && !OS(WIN)

[kcc1, 2014/02/06 13:44:06]

Why !OS(WIN)?
asan will be available on Windows eventually

[Mads Ager (chromium), 2014/02/06 14:15:17]

SyZyAsan uses the same define and they do not have this API (and they don't have
a fake stack). So, we shouldn't attempt to do this on Windows. 

+    void* m_asanFakeStack;
+#endif
 };
 
 template<ThreadAffinity affinity> class ThreadStateFor;
 
 template<> class ThreadStateFor<MainThreadOnly> {
 public:
     static ThreadState* state()
     {
         // This specialization must only be used from the main thread.
         ASSERT(ThreadState::isMainThread());
         return ThreadState::mainThreadState();
     }
 };
 
 template<> class ThreadStateFor<AnyThread> {
 public:
     static ThreadState* state() { return ThreadState::current(); }
 };
 
 }
 
 #endif // ThreadState_h