JavaScriptCore-1097.3.tar.gz

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

diff --git a/bytecode/PutByIdStatus.h b/bytecode/PutByIdStatus.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 PutByIdStatus_h
+#define PutByIdStatus_h
+
+#include <wtf/NotFound.h>
+
+namespace JSC {
+
+class CodeBlock;
+class Identifier;
+class Structure;
+class StructureChain;
+
+class PutByIdStatus {
+public:
+    enum State {
+        // It's uncached so we have no information.
+        NoInformation,
+        // It's cached as a direct store into an object property for cases where the object
+        // already has the property.
+        SimpleReplace,
+        // It's cached as a transition from one structure that lacks the property to one that
+        // includes the property, and a direct store to this new property.
+        SimpleTransition,
+        // It's known to often take slow path.
+        TakesSlowPath
+    };
+    
+    PutByIdStatus()
+        : m_state(NoInformation)
+        , m_oldStructure(0)
+        , m_newStructure(0)
+        , m_structureChain(0)
+        , m_offset(notFound)
+    {
+    }
+    
+    PutByIdStatus(
+        State state,
+        Structure* oldStructure,
+        Structure* newStructure,
+        StructureChain* structureChain,
+        size_t offset)
+        : m_state(state)
+        , m_oldStructure(oldStructure)
+        , m_newStructure(newStructure)
+        , m_structureChain(structureChain)
+        , m_offset(offset)
+    {
+        ASSERT((m_state == NoInformation || m_state == TakesSlowPath) == !m_oldStructure);
+        ASSERT((m_state != SimpleTransition) == !m_newStructure);
+        ASSERT((m_state != SimpleTransition) == !m_structureChain);
+        ASSERT((m_state == NoInformation || m_state == TakesSlowPath) == (m_offset == notFound));
+    }
+    
+    static PutByIdStatus computeFor(CodeBlock*, unsigned bytecodeIndex, Identifier&);
+    
+    State state() const { return m_state; }
+    
+    bool isSet() const { return m_state != NoInformation; }
+    bool operator!() const { return m_state == NoInformation; }
+    bool isSimpleReplace() const { return m_state == SimpleReplace; }
+    bool isSimpleTransition() const { return m_state == SimpleTransition; }
+    bool takesSlowPath() const { return m_state == TakesSlowPath; }
+    
+    Structure* oldStructure() const { return m_oldStructure; }
+    Structure* newStructure() const { return m_newStructure; }
+    StructureChain* structureChain() const { return m_structureChain; }
+    size_t offset() const { return m_offset; }
+    
+private:
+    static PutByIdStatus computeFromLLInt(CodeBlock*, unsigned bytecodeIndex, Identifier&);
+    
+    State m_state;
+    Structure* m_oldStructure;
+    Structure* m_newStructure;
+    StructureChain* m_structureChain;
+    size_t m_offset;
+};
+
+} // namespace JSC
+
+#endif // PutByIdStatus_h
+