[Oilpan] Add use-after-free detector in Member<>

third_party/WebKit/Source/platform/heap/Heap.h

Index: third_party/WebKit/Source/platform/heap/Heap.h
diff --git a/third_party/WebKit/Source/platform/heap/Heap.h b/third_party/WebKit/Source/platform/heap/Heap.h
index 67a8bc873ef643166d19459cecc0c07fab89dab3..99bdc1f6a855caa90e530e5ec145e3186fe095d0 100644
--- a/third_party/WebKit/Source/platform/heap/Heap.h
+++ b/third_party/WebKit/Source/platform/heap/Heap.h
@@ -47,6 +47,8 @@ template<typename T> class Member;
 template<typename T> class WeakMember;
 template<typename T> class UntracedMember;
 
+// TODO(peria): Refactor following two sets of template.
+
 template<typename T, bool = NeedsAdjustAndMark<T>::value> class ObjectAliveTrait;
 
 template<typename T>
@@ -69,6 +71,38 @@ public:
     }
 };
 
+template<typename T, bool = IsGarbageCollectedMixin<T>::value> class HeapObjectHeaderTrait;
+
+template<typename T>
+class HeapObjectHeaderTrait<T, true> {
+public:
+    static HeapObjectHeader* heapObjectHeader(T* obj)
+    {
+        return obj->heapObjectHeader();
+    }
+    static uint32_t gcGeneration(T* obj)
+    {
+        // While constructing GarbageCollectedMixin classes, we skip looking
+        // for gcGeneration, because the object may not be fully allocated.
+        if (ThreadState::current()->isConstructingGCMixin())
+            return 0;
+        return heapObjectHeader(obj)->gcGeneration();
+    }
+};
+
+template<typename T>
+class HeapObjectHeaderTrait<T, false> {
+public:
+    static HeapObjectHeader* heapObjectHeader(T* obj)
+    {
+        return HeapObjectHeader::fromPayload(obj);
+    }
+    static uint32_t gcGeneration(T* obj)
+    {
+        return heapObjectHeader(obj)->gcGeneration();
+    }
+};
+
 class PLATFORM_EXPORT Heap {
 public:
     static void init();
@@ -96,17 +130,17 @@ public:
     template<typename T>
     static inline bool isHeapObjectAlive(const Member<T>& member)
     {
-        return isHeapObjectAlive(member.get());
+        return isHeapObjectAlive(member.unsafeGet());
     }
     template<typename T>
     static inline bool isHeapObjectAlive(const WeakMember<T>& member)
     {
-        return isHeapObjectAlive(member.get());
+        return isHeapObjectAlive(member.unsafeGet());
     }
     template<typename T>
     static inline bool isHeapObjectAlive(const UntracedMember<T>& member)
     {
-        return isHeapObjectAlive(member.get());
+        return isHeapObjectAlive(member.unsafeGet());
     }
     template<typename T>
     static inline bool isHeapObjectAlive(const RawPtr<T>& ptr)
@@ -260,7 +294,7 @@ public:
     static void reportMemoryUsageForTracing();
 
 #if ENABLE(ASSERT)
-    static uint16_t gcGeneration() { return s_gcGeneration; }
+    static uint32_t gcGeneration() { return s_gcGeneration; }
 #endif
 
 private:
@@ -309,7 +343,7 @@ private:
     static size_t s_partitionAllocSizeAtLastGC;
     static double s_estimatedMarkingTimePerByte;
 #if ENABLE(ASSERT)
-    static uint16_t s_gcGeneration;
+    static uint32_t s_gcGeneration;
 #endif
 
     friend class ThreadState;
@@ -455,7 +489,7 @@ inline Address Heap::allocateOnHeapIndex(ThreadState* state, size_t size, int he
     ASSERT(state->isAllocationAllowed());
     ASSERT(heapIndex != BlinkGC::LargeObjectHeapIndex);
     NormalPageHeap* heap = static_cast<NormalPageHeap*>(state->heap(heapIndex));
-    return heap->allocateObject(allocationSizeFromSize(size), gcInfoIndex);
+    return heap->allocateObject(allocationSizeFromSize(size), gcInfoIndex, gcGeneration());
 }
 
 template<typename T>