Oilpan: Allocation should be allowed in pre-finalizers

Source/platform/heap/HeapTest.cpp

 /*
  * 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 1579 matching lines @@
         for (int i = 0; i < 32; ++i)
             LargeHeapObject::create();
     }
 
     DEFINE_INLINE_TRACE() { }
 
 private:
     Persistent<IntWrapper>* m_wrapper;
 };
 
+class PreFinalizationAllocator : public GarbageCollectedFinalized<PreFinalizationAllocator> {
+    USING_PRE_FINALIZER(PreFinalizationAllocator, dispose);
+public:
+    PreFinalizationAllocator(Persistent<IntWrapper>* wrapper)
+        : m_wrapper(wrapper)
+    {
+        ThreadState::current()->registerPreFinalizer(*this);
+    }
+
+    void dispose()
+    {
+        for (int i = 0; i < 10; ++i)
+            *m_wrapper = IntWrapper::create(42);
+        for (int i = 0; i < 512; ++i)
+            new OneKiloByteObject();
+        for (int i = 0; i < 32; ++i)
+            LargeHeapObject::create();
+    }
+
+    DEFINE_INLINE_TRACE() { }
+
+private:
+    Persistent<IntWrapper>* m_wrapper;
+};
+
 TEST(HeapTest, Transition)
 {
     {
         RefPtrWillBePersistent<TransitionRefCounted> refCounted = TransitionRefCounted::create();
         EXPECT_EQ(1, TransitionRefCounted::s_aliveCount);
         Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::GCWithSweep, Heap::ForcedGC);
         EXPECT_EQ(1, TransitionRefCounted::s_aliveCount);
     }
     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::GCWithSweep, Heap::ForcedGC);
     EXPECT_EQ(0, TransitionRefCounted::s_aliveCount);
@@ skipping 2686 matching lines @@
     // swept away and zapped later in the same sweeping phase.
     EXPECT_EQ(42, wrapper->value());
 
     wrapper.clear();
     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::GCWithSweep, Heap::ForcedGC);
     EXPECT_EQ(42, IntWrapper::s_destructorCalls);
     EXPECT_EQ(512, OneKiloByteObject::s_destructorCalls);
     EXPECT_EQ(32, LargeHeapObject::s_destructorCalls);
 }
 
+TEST(HeapTest, AllocationDuringPrefinalizer)
+{
+    clearOutOldGarbage();
+    IntWrapper::s_destructorCalls = 0;
+    OneKiloByteObject::s_destructorCalls = 0;
+    LargeHeapObject::s_destructorCalls = 0;
+
+    Persistent<IntWrapper> wrapper;
+    new PreFinalizationAllocator(&wrapper);
+
+    Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::GCWithSweep, Heap::ForcedGC);
+    EXPECT_EQ(0, IntWrapper::s_destructorCalls);
+    EXPECT_EQ(0, OneKiloByteObject::s_destructorCalls);
+    EXPECT_EQ(0, LargeHeapObject::s_destructorCalls);
+    // Check that the wrapper allocated during finalization is not
+    // swept away and zapped later in the same sweeping phase.
+    EXPECT_EQ(42, wrapper->value());
+
+    wrapper.clear();
+    Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::GCWithSweep, Heap::ForcedGC);
+    EXPECT_EQ(42, IntWrapper::s_destructorCalls);

[sof, 2015/06/18 12:18:03]

Could you add a comment where the 42 IntWrappers come from; saves a bit of time
for anyone trying to make sense of the pass condition later.

[haraken, 2015/06/18 16:30:13]

Done.

+    EXPECT_EQ(512, OneKiloByteObject::s_destructorCalls);
+    EXPECT_EQ(32, LargeHeapObject::s_destructorCalls);
+}
+
 class SimpleClassWithDestructor {
 public:
     SimpleClassWithDestructor() { }
     ~SimpleClassWithDestructor()
     {
         s_wasDestructed = true;
     }
     static bool s_wasDestructed;
 };
 
@@ skipping 1808 matching lines @@
 {
     Persistent<ClassWithMember> object = ClassWithMember::create();
     EXPECT_EQ(0, object->traceCount());
     TestMixinAllocatingObject* mixin = TestMixinAllocatingObject::create(object.get());
     EXPECT_TRUE(mixin);
     EXPECT_GT(object->traceCount(), 0);
     EXPECT_GT(mixin->traceCount(), 0);
 }
 
 } // namespace blink