Oilpan: Fix ASan instrumentation around heap object headers.

Source/platform/heap/Heap.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 1479 matching lines @@
 size_t HeapObjectHeader::payloadSize()
 {
     return size() - objectHeaderSize;
 }
 
 Address HeapObjectHeader::payloadEnd()
 {
     return reinterpret_cast<Address>(this) + size();
 }
 
+NO_SANITIZE_ADDRESS
 void HeapObjectHeader::mark()
 {
     checkHeader();
     // The use of atomic ops guarantees that the reads and writes are
     // atomic and that no memory operation reorderings take place.
     // Multiple threads can still read the old value and all store the
     // new value. However, the new value will be the same for all of
     // the threads and the end result is therefore consistent.
-    // We need to unpoison/poison the header on ASAN since
-    // acquireLoad/releaseStore don't have the NO_SANITIZE_ADDRESS flag.
-    ASAN_UNPOISON_MEMORY_REGION(this, sizeof(this));
+#if defined(ADDRESS_SANITIZER)

[zerny-chromium, 2014/09/09 06:01:28]

I'd prefer to avoid the code duplication by defining the asan variants for both
true and false values of defined(ADDRESS_SANITIZER).

[Mads Ager (chromium), 2014/09/09 08:22:14]

Done.

+    unsigned size = asanAcquireLoad(&m_size);
+    asanReleaseStore(&m_size, size | markBitMask);
+#else
     unsigned size = acquireLoad(&m_size);
     releaseStore(&m_size, size | markBitMask);
-    ASAN_POISON_MEMORY_REGION(this, sizeof(this));
+#endif
 }
 
 Address FinalizedHeapObjectHeader::payload()
 {
     return reinterpret_cast<Address>(this) + finalizedHeaderSize;
 }
 
 size_t FinalizedHeapObjectHeader::payloadSize()
 {
     return size() - finalizedHeaderSize;
@@ skipping 1047 matching lines @@
 };
 
 template<typename T>
 struct IfWeakMember<WeakMember<T> > {
     static bool isDead(Visitor* visitor, const WeakMember<T>& t) { return !visitor->isAlive(t.get()); }
 };
 
 }
 
 #endif // Heap_h