Oilpan: Introduce a state transition model for Oilpan GC states

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 178 matching lines @@
 namespace blink {
 
 class TestGCScope {
 public:
     explicit TestGCScope(ThreadState::StackState state)
         : m_state(ThreadState::current())
         , m_safePointScope(state)
         , m_parkedAllThreads(false)
     {
         m_state->checkThread();
-        EXPECT_FALSE(m_state->isInGC());
         if (LIKELY(ThreadState::stopThreads())) {
-            m_state->enterGC();
+            Heap::enterGC();
             m_parkedAllThreads = true;
         }
     }
 
     bool allThreadsParked() { return m_parkedAllThreads; }
 
     ~TestGCScope()
     {
         // Only cleanup if we parked all threads in which case the GC happened
         // and we need to resume the other threads.
         if (LIKELY(m_parkedAllThreads)) {
-            m_state->leaveGC();
-            EXPECT_FALSE(m_state->isInGC());
+            Heap::leaveGC();
             ThreadState::resumeThreads();
         }
     }
 
 private:
     ThreadState* m_state;
     ThreadState::SafePointScope m_safePointScope;
     bool m_parkedAllThreads; // False if we fail to park all threads
 };
 
@@ skipping 3121 matching lines @@
     // This is a low-level test where we call checkAndMarkPointer. This method
     // causes the object start bitmap to be computed which requires the heap
     // to be in a consistent state (e.g. the free allocation area must be put
     // into a free list header). However when we call makeConsistentForSweeping it
     // also clears out the freelists so we have to rebuild those before trying
     // to allocate anything again. We do this by forcing a GC after doing the
     // checkAndMarkPointer tests.
     {
         TestGCScope scope(ThreadState::HeapPointersOnStack);
         EXPECT_TRUE(scope.allThreadsParked()); // Fail the test if we could not park all threads.
-        Heap::prepareForGC();
+        Heap::preGC();
         Heap::flushHeapDoesNotContainCache();
         for (size_t i = 0; i < objectAddresses.size(); i++) {
             EXPECT_TRUE(Heap::checkAndMarkPointer(&visitor, objectAddresses[i]));
             EXPECT_TRUE(Heap::checkAndMarkPointer(&visitor, endAddresses[i]));
         }
         EXPECT_EQ(objectAddresses.size() * 2, visitor.count());
         visitor.reset();
         EXPECT_TRUE(Heap::checkAndMarkPointer(&visitor, largeObjectAddress));
         EXPECT_TRUE(Heap::checkAndMarkPointer(&visitor, largeObjectEndAddress));
         EXPECT_EQ(2ul, visitor.count());
         visitor.reset();
+        Heap::postGC();
     }
     // This forces a GC without stack scanning which results in the objects
     // being collected. This will also rebuild the above mentioned freelists,
     // however we don't rely on that below since we don't have any allocations.
     clearOutOldGarbage();
     {
         TestGCScope scope(ThreadState::HeapPointersOnStack);
         EXPECT_TRUE(scope.allThreadsParked());
-        Heap::prepareForGC();
+        Heap::preGC();
         Heap::flushHeapDoesNotContainCache();
         for (size_t i = 0; i < objectAddresses.size(); i++) {
             // We would like to assert that checkAndMarkPointer returned false
             // here because the pointers no longer point into a valid object
             // (it's been freed by the GCs. But checkAndMarkPointer will return
             // true for any pointer that points into a heap page, regardless of
             // whether it points at a valid object (this ensures the
             // correctness of the page-based on-heap address caches), so we
             // can't make that assert.
             Heap::checkAndMarkPointer(&visitor, objectAddresses[i]);
             Heap::checkAndMarkPointer(&visitor, endAddresses[i]);
         }
         EXPECT_EQ(0ul, visitor.count());
         Heap::checkAndMarkPointer(&visitor, largeObjectAddress);
         Heap::checkAndMarkPointer(&visitor, largeObjectEndAddress);
         EXPECT_EQ(0ul, visitor.count());
+        Heap::postGC();
     }
     // This round of GC is important to make sure that the object start
     // bitmap are cleared out and that the free lists are rebuild.
     clearOutOldGarbage();
 }
 
 TEST(HeapTest, VisitOffHeapCollections)
 {
     clearOutOldGarbage();
     IntWrapper::s_destructorCalls = 0;
@@ skipping 1823 matching lines @@
 TEST(HeapTest, NonNodeAllocatingNodeInDestructor)
 {
     new NonNodeAllocatingNodeInDestructor();
     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack);
     EXPECT_EQ(10, (*NonNodeAllocatingNodeInDestructor::s_node)->value());
     delete NonNodeAllocatingNodeInDestructor::s_node;
     NonNodeAllocatingNodeInDestructor::s_node = 0;
 }
 
 } // namespace blink