Merge WebKit at r84325: Initial merge by git.

Change-Id: Ic1a909300ecc0a13ddc6b4e784371d2ac6e3d59b

1 files changed, 295 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/heap/MarkStack.h b/Source/JavaScriptCore/heap/MarkStack.h
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+++ b/Source/JavaScriptCore/heap/MarkStack.h
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+/*
+ * Copyright (C) 2009, 2011 Apple 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:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef MarkStack_h
+#define MarkStack_h
+
+#include "JSValue.h"
+#include "Register.h"
+#include "WriteBarrier.h"
+#include <wtf/HashSet.h>
+#include <wtf/Vector.h>
+#include <wtf/Noncopyable.h>
+#include <wtf/OSAllocator.h>
+
+namespace JSC {
+
+    class ConservativeRoots;
+    class JSGlobalData;
+    class Register;
+    
+    enum MarkSetProperties { MayContainNullValues, NoNullValues };
+    
+    class MarkStack {
+        WTF_MAKE_NONCOPYABLE(MarkStack);
+    public:
+        MarkStack(void* jsArrayVPtr)
+            : m_jsArrayVPtr(jsArrayVPtr)
+#if !ASSERT_DISABLED
+            , m_isCheckingForDefaultMarkViolation(false)
+            , m_isDraining(false)
+#endif
+        {
+        }
+
+        ~MarkStack()
+        {
+            ASSERT(m_markSets.isEmpty());
+            ASSERT(m_values.isEmpty());
+        }
+
+        void deprecatedAppend(JSCell**);
+        template <typename T> void append(WriteBarrierBase<T>*);
+
+        void appendValues(WriteBarrierBase<Unknown>* barriers, size_t count, MarkSetProperties properties = NoNullValues)
+        {
+            JSValue* values = barriers->slot();
+            if (count)
+                m_markSets.append(MarkSet(values, values + count, properties));
+        }
+        
+        void append(ConservativeRoots&);
+
+        bool addOpaqueRoot(void* root) { return m_opaqueRoots.add(root).second; }
+        bool containsOpaqueRoot(void* root) { return m_opaqueRoots.contains(root); }
+        int opaqueRootCount() { return m_opaqueRoots.size(); }
+
+        void drain();
+        void reset();
+
+    private:
+        friend class HeapRootMarker; // Allowed to mark a JSValue* or JSCell** directly.
+        void append(JSValue*);
+        void append(JSValue*, size_t count);
+        void append(JSCell**);
+
+        void internalAppend(JSCell*);
+        void internalAppend(JSValue);
+        void markChildren(JSCell*);
+
+        struct MarkSet {
+            MarkSet(JSValue* values, JSValue* end, MarkSetProperties properties)
+                : m_values(values)
+                , m_end(end)
+                , m_properties(properties)
+            {
+                ASSERT(values);
+            }
+            JSValue* m_values;
+            JSValue* m_end;
+            MarkSetProperties m_properties;
+        };
+
+        static void* allocateStack(size_t size) { return OSAllocator::reserveAndCommit(size); }
+        static void releaseStack(void* addr, size_t size) { OSAllocator::decommitAndRelease(addr, size); }
+
+        static void initializePagesize();
+        static size_t pageSize()
+        {
+            if (!s_pageSize)
+                initializePagesize();
+            return s_pageSize;
+        }
+
+        template <typename T> struct MarkStackArray {
+            MarkStackArray()
+                : m_top(0)
+                , m_allocated(MarkStack::pageSize())
+                , m_capacity(m_allocated / sizeof(T))
+            {
+                m_data = reinterpret_cast<T*>(allocateStack(m_allocated));
+            }
+
+            ~MarkStackArray()
+            {
+                releaseStack(m_data, m_allocated);
+            }
+
+            void expand()
+            {
+                size_t oldAllocation = m_allocated;
+                m_allocated *= 2;
+                m_capacity = m_allocated / sizeof(T);
+                void* newData = allocateStack(m_allocated);
+                memcpy(newData, m_data, oldAllocation);
+                releaseStack(m_data, oldAllocation);
+                m_data = reinterpret_cast<T*>(newData);
+            }
+
+            inline void append(const T& v)
+            {
+                if (m_top == m_capacity)
+                    expand();
+                m_data[m_top++] = v;
+            }
+
+            inline T removeLast()
+            {
+                ASSERT(m_top);
+                return m_data[--m_top];
+            }
+            
+            inline T& last()
+            {
+                ASSERT(m_top);
+                return m_data[m_top - 1];
+            }
+
+            inline bool isEmpty()
+            {
+                return m_top == 0;
+            }
+
+            inline size_t size() { return m_top; }
+
+            inline void shrinkAllocation(size_t size)
+            {
+                ASSERT(size <= m_allocated);
+                ASSERT(0 == (size % MarkStack::pageSize()));
+                if (size == m_allocated)
+                    return;
+#if OS(WINDOWS) || OS(SYMBIAN) || PLATFORM(BREWMP)
+                // We cannot release a part of a region with VirtualFree.  To get around this,
+                // we'll release the entire region and reallocate the size that we want.
+                releaseStack(m_data, m_allocated);
+                m_data = reinterpret_cast<T*>(allocateStack(size));
+#else
+                releaseStack(reinterpret_cast<char*>(m_data) + size, m_allocated - size);
+#endif
+                m_allocated = size;
+                m_capacity = m_allocated / sizeof(T);
+            }
+
+        private:
+            size_t m_top;
+            size_t m_allocated;
+            size_t m_capacity;
+            T* m_data;
+        };
+
+        void* m_jsArrayVPtr;
+        MarkStackArray<MarkSet> m_markSets;
+        MarkStackArray<JSCell*> m_values;
+        static size_t s_pageSize;
+        HashSet<void*> m_opaqueRoots; // Handle-owning data structures not visible to the garbage collector.
+
+#if !ASSERT_DISABLED
+    public:
+        bool m_isCheckingForDefaultMarkViolation;
+        bool m_isDraining;
+#endif
+    };
+
+    inline void MarkStack::append(JSValue* slot, size_t count)
+    {
+        if (!count)
+            return;
+        m_markSets.append(MarkSet(slot, slot + count, NoNullValues));
+    }
+    
+    template <typename T> inline void MarkStack::append(WriteBarrierBase<T>* slot)
+    {
+        internalAppend(*slot->slot());
+    }
+
+    ALWAYS_INLINE void MarkStack::deprecatedAppend(JSCell** value)
+    {
+        ASSERT(value);
+        internalAppend(*value);
+    }
+
+    ALWAYS_INLINE void MarkStack::append(JSValue* value)
+    {
+        ASSERT(value);
+        internalAppend(*value);
+    }
+
+    ALWAYS_INLINE void MarkStack::append(JSCell** value)
+    {
+        ASSERT(value);
+        internalAppend(*value);
+    }
+
+    ALWAYS_INLINE void MarkStack::internalAppend(JSValue value)
+    {
+        ASSERT(value);
+        if (value.isCell())
+            internalAppend(value.asCell());
+    }
+
+    // Privileged class for marking JSValues directly. It is only safe to use
+    // this class to mark direct heap roots that are marked during every GC pass.
+    // All other references should be wrapped in WriteBarriers and marked through
+    // the MarkStack.
+    class HeapRootMarker {
+    private:
+        friend class Heap;
+        HeapRootMarker(MarkStack&);
+        
+    public:
+        void mark(JSValue*);
+        void mark(JSValue*, size_t);
+        void mark(JSString**);
+        void mark(JSCell**);
+        
+        MarkStack& markStack();
+
+    private:
+        MarkStack& m_markStack;
+    };
+
+    inline HeapRootMarker::HeapRootMarker(MarkStack& markStack)
+        : m_markStack(markStack)
+    {
+    }
+
+    inline void HeapRootMarker::mark(JSValue* slot)
+    {
+        m_markStack.append(slot);
+    }
+
+    inline void HeapRootMarker::mark(JSValue* slot, size_t count)
+    {
+        m_markStack.append(slot, count);
+    }
+
+    inline void HeapRootMarker::mark(JSString** slot)
+    {
+        m_markStack.append(reinterpret_cast<JSCell**>(slot));
+    }
+
+    inline void HeapRootMarker::mark(JSCell** slot)
+    {
+        m_markStack.append(slot);
+    }
+
+    inline MarkStack& HeapRootMarker::markStack()
+    {
+        return m_markStack;
+    }
+
+} // namespace JSC
+
+#endif