Refactor the Heap into ThreadHeap to prepare for per thread heaps

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MarkingVisitorImpl_h
 #define MarkingVisitorImpl_h
 
 #include "platform/heap/Heap.h"
 #include "platform/heap/ThreadState.h"
 #include "platform/heap/Visitor.h"
@@ skipping 20 matching lines @@
         // from a live thread heap to a dead thread heap.  We must eliminate
         // the dangling pointer.
         // Release builds don't have the ASSERT, but it is OK because
         // release builds will crash in the following header->isMarked()
         // because all the entries of the orphaned heaps are zapped.
         ASSERT(!pageFromObject(objectPointer)->orphaned());
 
         if (header->isMarked())
             return;
 
-        ASSERT(ThreadState::current()->isInGC());
+        ASSERT(toDerived()->threadState()->isInGC());
+        if (toDerived()->threadState()->perThreadHeapEnabled())
+            RELEASE_ASSERT(ThreadState::forObject(objectPointer) == toDerived()->threadState());

[haraken, 2016/01/07 08:06:22]

forObject => fromObject

[haraken, 2016/01/07 08:06:22]

Hmm. This RELEASE_ASSERT would be a bit problematic for the following two
reasons:

- markHeader must be super fast to minimize GC's pause time. I want to avoid
introducing an if branch and the ASSERT.

- The ASSERT checks that a per-thread heap's GC doesn't trace into a
non-per-thread heap, but it doesn't check that a non-per-thread heap's GC
doesn't trace into a per-thread heap.

That said, I have no alternative idea at the moment. Let me think about it more.

 #if !defined(NDEBUG)
-        ASSERT(Heap::findPageFromAddress(header));
+        else
+            ASSERT(Heap::findPageFromAddress(header));
 #endif
         ASSERT(toDerived()->markingMode() != Visitor::WeakProcessing);
 
         header->mark();
 
         if (callback)
-            Heap::pushTraceCallback(const_cast<void*>(objectPointer), callback);
+            Heap::pushTraceCallback(const_cast<void*>(objectPointer), callback, toDerived()->threadState());
     }
 
     inline void mark(const void* objectPointer, TraceCallback callback)
     {
         if (!objectPointer)
             return;
         HeapObjectHeader* header = HeapObjectHeader::fromPayload(objectPointer);
         markHeader(header, header->payload(), callback);
     }
 
     inline void registerDelayedMarkNoTracing(const void* objectPointer)
     {
         ASSERT(toDerived()->markingMode() != Visitor::WeakProcessing);
         Heap::pushPostMarkingCallback(const_cast<void*>(objectPointer), &markNoTracingCallback);
     }
 
     inline void registerWeakMembers(const void* closure, const void* objectPointer, WeakCallback callback)
     {
         ASSERT(toDerived()->markingMode() != Visitor::WeakProcessing);
         // We don't want to run weak processings when taking a snapshot.
         if (toDerived()->markingMode() == Visitor::SnapshotMarking)
             return;
         Heap::pushThreadLocalWeakCallback(const_cast<void*>(closure), const_cast<void*>(objectPointer), callback);
     }
 
     inline void registerWeakTable(const void* closure, EphemeronCallback iterationCallback, EphemeronCallback iterationDoneCallback)
     {
         ASSERT(toDerived()->markingMode() != Visitor::WeakProcessing);
-        Heap::registerWeakTable(const_cast<void*>(closure), iterationCallback, iterationDoneCallback);
+        Heap::registerWeakTable(const_cast<void*>(closure), iterationCallback, iterationDoneCallback, toDerived()->threadState());
     }
 
 #if ENABLE(ASSERT)
     inline bool weakTableRegistered(const void* closure)
     {
-        return Heap::weakTableRegistered(closure);
+        return Heap::weakTableRegistered(closure, toDerived()->threadState());
     }
 #endif
 
     inline bool ensureMarked(const void* objectPointer)
     {
         if (!objectPointer)
             return false;
         if (!toDerived()->shouldMarkObject(objectPointer))
             return false;
 #if ENABLE(ASSERT)
@@ skipping 17 matching lines @@
         return static_cast<Derived*>(this);
     }
 
 protected:
     inline void registerWeakCellWithCallback(void** cell, WeakCallback callback)
     {
         ASSERT(toDerived()->markingMode() != Visitor::WeakProcessing);
         // We don't want to run weak processings when taking a snapshot.
         if (toDerived()->markingMode() == Visitor::SnapshotMarking)
             return;
-        Heap::pushGlobalWeakCallback(cell, callback);
+        Heap::pushGlobalWeakCallback(cell, callback, toDerived()->threadState());
     }
 
 private:
     static void markNoTracingCallback(Visitor* visitor, void* object)
     {
         visitor->markNoTracing(object);
     }
 };
 
 } // namespace blink
 
 #endif