Introduce infrastructure for tracing ScriptWrappables.

third_party/WebKit/Source/platform/heap/HeapPage.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 124 matching lines @@
 // | gcInfoIndex (14 bit) | DOM mark bit (1 bit) | size (14 bit) | dead bit (1 bit) | freed bit (1 bit) | mark bit (1 bit) |
 //
 // - For non-large objects, 14 bit is enough for |size| because the blink
 //   page size is 2^17 byte and each object is guaranteed to be aligned with
 //   2^3 byte.
 // - For large objects, |size| is 0. The actual size of a large object is
 //   stored in LargeObjectPage::m_payloadSize.
 // - 1 bit used to mark DOM trees for V8.
 // - 14 bit is enough for gcInfoIndex because there are less than 2^14 types
 //   in Blink.
-const size_t headerDOMMarkBitMask = 1u << 17;
+const size_t headerWrapperMarkBitMast = 1u << 17;

[Hannes Payer (out of office), 2016/04/19 07:44:33]

headerWrapperMarkBitMask

[Marcel Hlopko, 2016/04/19 12:40:30]

Done.

 const size_t headerGCInfoIndexShift = 18;
 const size_t headerGCInfoIndexMask = (static_cast<size_t>((1 << 14) - 1)) << headerGCInfoIndexShift;
 const size_t headerSizeMask = (static_cast<size_t>((1 << 14) - 1)) << 3;
 const size_t headerMarkBitMask = 1;
 const size_t headerFreedBitMask = 2;
 // The dead bit is used for objects that have gone through a GC marking, but did
 // not get swept before a new GC started. In that case we set the dead bit on
 // objects that were not marked in the previous GC to ensure we are not tracing
 // them via a conservatively found pointer. Tracing dead objects could lead to
 // tracing of already finalized objects in another thread's heap which is a
@@ skipping 42 matching lines @@
     size_t size() const;
 
     NO_SANITIZE_ADDRESS
     size_t gcInfoIndex() const { return (m_encoded & headerGCInfoIndexMask) >> headerGCInfoIndexShift; }
     NO_SANITIZE_ADDRESS
     void setSize(size_t size)
     {
         ASSERT(size < nonLargeObjectPageSizeMax);
         m_encoded = static_cast<uint32_t>(size) | (m_encoded & ~headerSizeMask);
     }
+    bool isWrapperMarked() const;
+    void markWrapper();
+    void unmarkWrapper();

[haraken, 2016/04/19 04:58:31]

isWrapperHeaderMarked
markWrapperHeader
unmarkWrapperHeader

[Marcel Hlopko, 2016/04/19 12:40:30]

Done.

[Marcel Hlopko, 2016/04/19 12:40:30]

Done.

     bool isMarked() const;
     void mark();
     void unmark();
     void markDead();
     bool isDead() const;
 
     Address payload();
     size_t payloadSize();
     Address payloadEnd();
 
@@ skipping 610 matching lines @@
 
 inline HeapObjectHeader* HeapObjectHeader::fromPayload(const void* payload)
 {
     Address addr = reinterpret_cast<Address>(const_cast<void*>(payload));
     HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(addr - sizeof(HeapObjectHeader));
     ASSERT(header->checkHeader());
     return header;
 }
 
 NO_SANITIZE_ADDRESS inline
+bool HeapObjectHeader::isWrapperMarked() const
+{
+    ASSERT(checkHeader());
+    return m_encoded & headerWrapperMarkBitMast;
+}
+
+NO_SANITIZE_ADDRESS inline
+void HeapObjectHeader::markWrapper()
+{
+    ASSERT(checkHeader());
+    ASSERT(!isWrapperMarked());
+    m_encoded |= headerWrapperMarkBitMast;
+}
+
+NO_SANITIZE_ADDRESS inline
+void HeapObjectHeader::unmarkWrapper()
+{
+    ASSERT(checkHeader());
+    ASSERT(isWrapperMarked());
+    m_encoded &= ~headerWrapperMarkBitMast;
+}
+
+NO_SANITIZE_ADDRESS inline
 bool HeapObjectHeader::isMarked() const
 {
     ASSERT(checkHeader());
     return m_encoded & headerMarkBitMask;
 }
 
 NO_SANITIZE_ADDRESS inline
 void HeapObjectHeader::mark()
 {
     ASSERT(checkHeader());
@@ skipping 38 matching lines @@
         SET_MEMORY_ACCESSIBLE(result, allocationSize - sizeof(HeapObjectHeader));
         ASSERT(findPageFromAddress(headerAddress + allocationSize - 1));
         return result;
     }
     return outOfLineAllocate(allocationSize, gcInfoIndex);
 }
 
 } // namespace blink
 
 #endif // HeapPage_h