JavaScriptCore-1218.tar.gz

[apple/javascriptcore.git] / bytecode / ArrayAllocationProfile.h

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+/*
+ * Copyright (C) 2012 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 ArrayAllocationProfile_h
+#define ArrayAllocationProfile_h
+
+#include "IndexingType.h"
+#include "JSArray.h"
+
+namespace JSC {
+
+class ArrayAllocationProfile {
+public:
+    ArrayAllocationProfile()
+        : m_currentIndexingType(ArrayWithUndecided)
+        , m_lastArray(0)
+    {
+    }
+    
+    IndexingType selectIndexingType()
+    {
+        if (m_lastArray && UNLIKELY(m_lastArray->structure()->indexingType() != m_currentIndexingType))
+            updateIndexingType();
+        return m_currentIndexingType;
+    }
+    
+    JSArray* updateLastAllocation(JSArray* lastArray)
+    {
+        m_lastArray = lastArray;
+        return lastArray;
+    }
+    
+    JS_EXPORT_PRIVATE void updateIndexingType();
+    
+    static IndexingType selectIndexingTypeFor(ArrayAllocationProfile* profile)
+    {
+        if (!profile)
+            return ArrayWithUndecided;
+        return profile->selectIndexingType();
+    }
+    
+    static JSArray* updateLastAllocationFor(ArrayAllocationProfile* profile, JSArray* lastArray)
+    {
+        if (profile)
+            profile->updateLastAllocation(lastArray);
+        return lastArray;
+    }
+
+private:
+    
+    IndexingType m_currentIndexingType;
+    JSArray* m_lastArray;
+};
+
+} // namespace JSC
+
+#endif // ArrayAllocationProfile_h
+