Unpoison CrossThreadPersistents

third_party/WebKit/Source/platform/heap/PersistentNode.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/heap/PersistentNode.h"
 
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
@@ skipping 69 matching lines @@
   m_freeListHead = nullptr;
   int persistentCount = 0;
   PersistentNodeSlots** prevNext = &m_slots;
   PersistentNodeSlots* slots = m_slots;
   while (slots) {
     PersistentNode* freeListNext = nullptr;
     PersistentNode* freeListLast = nullptr;
     int freeCount = 0;
     for (int i = 0; i < PersistentNodeSlots::slotCount; ++i) {
       PersistentNode* node = &slots->m_slot[i];
+      ASAN_UNPOISON_MEMORY_REGION(node->self(),
+                                  sizeof(CrossThreadPersistent<void*>));

[haraken, 2016/10/17 03:55:22]

Would you help me understand who poisons the memory region of node->self()?

I'm wondering if there's an option to simply stop poisoning heap pages for
CrossThreadPersistents.

       if (node->isUnused()) {
         if (!freeListNext)
           freeListLast = node;
         node->setFreeListNext(freeListNext);
         freeListNext = node;
         ++freeCount;
       } else {
         ++persistentCount;
         if (!shouldTrace(visitor, node))
           continue;
@@ skipping 67 matching lines @@
       if (page->arena()->getThreadState() == threadState) {
         persistent->clear();
         ASSERT(slots->m_slot[i].isUnused());
       }
     }
     slots = slots->m_next;
   }
 }
 
 }  // namespace blink