1 files changed, 169 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/dfg/DFGAvailability.h b/Source/JavaScriptCore/dfg/DFGAvailability.h
new file mode 100644
index 000000000..507d816aa
--- /dev/null
+++ b/Source/JavaScriptCore/dfg/DFGAvailability.h
@@ -0,0 +1,169 @@
+/*
+ * Copyright (C) 2013 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 DFGAvailability_h
+#define DFGAvailability_h
+
+#if ENABLE(DFG_JIT)
+
+#include "DFGFlushedAt.h"
+#include "DFGVariableAccessData.h"
+
+namespace JSC { namespace DFG {
+
+struct Node;
+
+class Availability {
+public:
+    Availability()
+        : m_node(0)
+        , m_flushedAt(DeadFlush)
+    {
+    }
+    
+    explicit Availability(Node* node)
+        : m_node(node)
+        , m_flushedAt(ConflictingFlush)
+    {
+    }
+    
+    explicit Availability(FlushedAt flushedAt)
+        : m_node(unavailableMarker())
+        , m_flushedAt(flushedAt)
+    {
+    }
+    
+    Availability(Node* node, FlushedAt flushedAt)
+        : m_node(node)
+        , m_flushedAt(flushedAt)
+    {
+    }
+    
+    static Availability unavailable()
+    {
+        return Availability(unavailableMarker(), FlushedAt(ConflictingFlush));
+    }
+    
+    Availability withFlush(FlushedAt flush) const
+    {
+        return Availability(m_node, flush);
+    }
+    
+    Availability withNode(Node* node) const
+    {
+        return Availability(node, m_flushedAt);
+    }
+    
+    Availability withUnavailableNode() const
+    {
+        return withNode(unavailableMarker());
+    }
+    
+    void setFlush(FlushedAt flushedAt)
+    {
+        m_flushedAt = flushedAt;
+    }
+    
+    void setNode(Node* node)
+    {
+        m_node = node;
+    }
+    
+    void setNodeUnavailable()
+    {
+        m_node = unavailableMarker();
+    }
+    
+    bool nodeIsUndecided() const { return !m_node; }
+    bool nodeIsUnavailable() const { return m_node == unavailableMarker(); }
+    
+    bool hasNode() const { return !nodeIsUndecided() && !nodeIsUnavailable(); }
+    bool shouldUseNode() const { return !isFlushUseful() && hasNode(); }
+    
+    Node* node() const
+    {
+        ASSERT(!nodeIsUndecided());
+        ASSERT(!nodeIsUnavailable());
+        return m_node;
+    }
+    
+    FlushedAt flushedAt() const { return m_flushedAt; }
+    bool isFlushUseful() const
+    {
+        return flushedAt().format() != DeadFlush && flushedAt().format() != ConflictingFlush;
+    }
+    
+    bool isDead() const { return !isFlushUseful() && !hasNode(); }
+    
+    bool operator!() const { return nodeIsUnavailable() && flushedAt().format() == ConflictingFlush; }
+
+    bool operator==(const Availability& other) const
+    {
+        return m_node == other.m_node
+            && m_flushedAt == other.m_flushedAt;
+    }
+    
+    bool operator!=(const Availability& other) const
+    {
+        return !(*this == other);
+    }
+    
+    Availability merge(const Availability& other) const
+    {
+        return Availability(
+            mergeNodes(m_node, other.m_node),
+            m_flushedAt.merge(other.m_flushedAt));
+    }
+    
+    void dump(PrintStream&) const;
+    void dumpInContext(PrintStream&, DumpContext*) const;
+
+private:
+    static Node* mergeNodes(Node* a, Node* b)
+    {
+        if (!a)
+            return b;
+        if (!b)
+            return a;
+        if (a == b)
+            return a;
+        return unavailableMarker();
+    }
+    
+    static Node* unavailableMarker()
+    {
+        return bitwise_cast<Node*>(static_cast<intptr_t>(1));
+    }
+    
+    Node* m_node;
+    FlushedAt m_flushedAt;
+};
+
+} } // namespace JSC::DFG
+
+#endif // ENABLE(DFG_JIT)
+
+#endif // DFGAvailability_h
+