Merge in WebKit r47029.

1 files changed, 171 insertions, 0 deletions

diff --git a/JavaScriptCore/runtime/MarkStack.h b/JavaScriptCore/runtime/MarkStack.h
new file mode 100644
index 0000000..7a7b3af
--- /dev/null
+++ b/JavaScriptCore/runtime/MarkStack.h
@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2009 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 <wtf/Noncopyable.h>
+
+namespace JSC {
+    class Register;
+    
+    enum MarkSetProperties { MayContainNullValues, NoNullValues };
+    
+    class MarkStack : Noncopyable {
+    public:
+        MarkStack()
+            : m_markSets()
+            , m_values()
+        {
+        }
+
+        ALWAYS_INLINE void append(JSValue value)
+        {
+            ASSERT(value);
+            if (value.marked())
+                return;
+            value.markDirect();
+            if (value.hasChildren())
+                m_values.append(value.asCell());
+        }
+
+        ALWAYS_INLINE void append(JSCell* cell);
+        
+        ALWAYS_INLINE void appendValues(Register* values, size_t count, MarkSetProperties properties = NoNullValues)
+        {
+            appendValues(reinterpret_cast<JSValue*>(values), count, properties);
+        }
+
+        ALWAYS_INLINE void appendValues(JSValue* values, size_t count, MarkSetProperties properties = NoNullValues)
+        {
+            if (count)
+                m_markSets.append(MarkSet(values, values + count, properties));
+        }
+
+        inline void drain();
+        void compact();
+
+        ~MarkStack()
+        {
+            ASSERT(m_markSets.isEmpty());
+            ASSERT(m_values.isEmpty());
+        }
+
+    private:
+        struct MarkSet {
+            MarkSet(JSValue* values, JSValue* end, MarkSetProperties properties)
+                : m_values(values)
+                , m_end(end)
+                , m_properties(properties)
+            {
+            }
+            JSValue* m_values;
+            JSValue* m_end;
+            MarkSetProperties m_properties;
+        };
+
+        static void* allocateStack(size_t size);
+        static void releaseStack(void* addr, size_t 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 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;
+                releaseStack(reinterpret_cast<char*>(m_data) + size, m_allocated - size);
+                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;
+        };
+
+        MarkStackArray<MarkSet> m_markSets;
+        MarkStackArray<JSCell*> m_values;
+        static size_t s_pageSize;
+    };
+}
+
+#endif