[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..b2322ca75e24f1e74c41bb8be11a747f6d4edbf2 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)
+    {

[haraken, 2015/11/16 02:47:49]

Can you add:

  static_assert(sizeof(T), "T must be fully defined");

?

[peria, 2015/11/16 05:33:26]

Done.

+        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)
+    {

[haraken, 2015/11/16 02:47:50]

Can you add:

  ASSERT(!ThreadState::current()->isConstructingGCMixin());

?

[peria, 2015/11/16 05:33:26]

We did the same discussion in #16
https://codereview.chromium.org/1411603007/diff/200001/third_party/WebKit/Sou...

+        return HeapObjectHeader::fromPayload(obj);

[haraken, 2015/11/16 02:47:49]

Can you add:

  ASSERT(header->checkHeader());

for the returned header?

[peria, 2015/11/16 05:33:26]

It is called in HeapObjectHeader::fromPayload().

+    }
+    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)
@@ -259,9 +293,7 @@ public:
     static void reportMemoryUsageHistogram();
     static void reportMemoryUsageForTracing();
 
-#if ENABLE(ASSERT)
-    static uint16_t gcGeneration() { return s_gcGeneration; }
-#endif
+    static uint32_t gcGeneration() { return s_gcGeneration; }
 
 private:
     // A RegionTree is a simple binary search tree of PageMemoryRegions sorted
@@ -308,9 +340,7 @@ private:
     static size_t s_collectedWrapperCount;
     static size_t s_partitionAllocSizeAtLastGC;
     static double s_estimatedMarkingTimePerByte;
-#if ENABLE(ASSERT)
-    static uint16_t s_gcGeneration;
-#endif
+    static uint32_t s_gcGeneration;
 
     friend class ThreadState;
 };
@@ -455,7 +485,7 @@ 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>