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diff --git a/Source/JavaScriptCore/dfg/DFGVirtualRegisterAllocationPhase.cpp b/Source/JavaScriptCore/dfg/DFGVirtualRegisterAllocationPhase.cpp
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+++ b/Source/JavaScriptCore/dfg/DFGVirtualRegisterAllocationPhase.cpp
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+/*
+ * Copyright (C) 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. 
+ */
+
+#include "config.h"
+#include "DFGVirtualRegisterAllocationPhase.h"
+
+#if ENABLE(DFG_JIT)
+
+#include "DFGGraph.h"
+#include "DFGScoreBoard.h"
+
+namespace JSC { namespace DFG {
+
+class VirtualRegisterAllocationPhase : public Phase {
+public:
+    VirtualRegisterAllocationPhase(Graph& graph)
+        : Phase(graph, "virtual register allocation")
+    {
+    }
+    
+    void run()
+    {
+#if DFG_ENABLE(DEBUG_VERBOSE)
+        dataLog("Preserved vars: ");
+        m_graph.m_preservedVars.dump(WTF::dataFile());
+        dataLog("\n");
+#endif
+        ScoreBoard scoreBoard(m_graph, m_graph.m_preservedVars);
+        unsigned sizeExcludingPhiNodes = m_graph.m_blocks.last()->end;
+        for (size_t i = 0; i < sizeExcludingPhiNodes; ++i) {
+            Node& node = m_graph[i];
+        
+            if (!node.shouldGenerate())
+                continue;
+        
+            // GetLocal nodes are effectively phi nodes in the graph, referencing
+            // results from prior blocks.
+            if (node.op != GetLocal) {
+                // First, call use on all of the current node's children, then
+                // allocate a VirtualRegister for this node. We do so in this
+                // order so that if a child is on its last use, and a
+                // VirtualRegister is freed, then it may be reused for node.
+                if (node.op & NodeHasVarArgs) {
+                    for (unsigned childIdx = node.firstChild(); childIdx < node.firstChild() + node.numChildren(); childIdx++)
+                        scoreBoard.use(m_graph.m_varArgChildren[childIdx]);
+                } else {
+                    scoreBoard.use(node.child1());
+                    scoreBoard.use(node.child2());
+                    scoreBoard.use(node.child3());
+                }
+            }
+
+            if (!node.hasResult())
+                continue;
+
+            node.setVirtualRegister(scoreBoard.allocate());
+            // 'mustGenerate' nodes have their useCount artificially elevated,
+            // call use now to account for this.
+            if (node.mustGenerate())
+                scoreBoard.use(i);
+        }
+
+        // 'm_numCalleeRegisters' is the number of locals and temporaries allocated
+        // for the function (and checked for on entry). Since we perform a new and
+        // different allocation of temporaries, more registers may now be required.
+        unsigned calleeRegisters = scoreBoard.highWatermark() + m_graph.m_parameterSlots;
+        if ((unsigned)codeBlock()->m_numCalleeRegisters < calleeRegisters)
+            codeBlock()->m_numCalleeRegisters = calleeRegisters;
+#if DFG_ENABLE(DEBUG_VERBOSE)
+        dataLog("Num callee registers: %u\n", calleeRegisters);
+#endif
+    }
+};
+
+void performVirtualRegisterAllocation(Graph& graph)
+{
+    runPhase<VirtualRegisterAllocationPhase>(graph);
+}
+
+} } // namespace JSC::DFG
+
+#endif // ENABLE(DFG_JIT)