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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, 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. 
+ */
+
+#include "config.h"
+#include "DFGVirtualRegisterAllocationPhase.h"
+
+#if ENABLE(DFG_JIT)
+
+#include "DFGGraph.h"
+#include "DFGScoreBoard.h"
+#include "JSCInlines.h"
+#include "StackAlignment.h"
+#include <wtf/StdLibExtras.h>
+
+namespace JSC { namespace DFG {
+
+class VirtualRegisterAllocationPhase : public Phase {
+public:
+    VirtualRegisterAllocationPhase(Graph& graph)
+        : Phase(graph, "virtual register allocation")
+    {
+    }
+    
+    bool run()
+    {
+        DFG_ASSERT(m_graph, nullptr, m_graph.m_form == ThreadedCPS);
+        
+        ScoreBoard scoreBoard(m_graph.m_nextMachineLocal);
+        scoreBoard.assertClear();
+        for (size_t blockIndex = 0; blockIndex < m_graph.numBlocks(); ++blockIndex) {
+            BasicBlock* block = m_graph.block(blockIndex);
+            if (!block)
+                continue;
+            if (!block->isReachable)
+                continue;
+            if (!ASSERT_DISABLED) {
+                // Force usage of highest-numbered virtual registers.
+                scoreBoard.sortFree();
+            }
+            for (size_t indexInBlock = 0; indexInBlock < block->size(); ++indexInBlock) {
+                Node* node = block->at(indexInBlock);
+        
+                if (!node->shouldGenerate())
+                    continue;
+                
+                switch (node->op()) {
+                case Phi:
+                case Flush:
+                case PhantomLocal:
+                    continue;
+                case GetLocal:
+                    ASSERT(!node->child1()->hasResult());
+                    break;
+                default:
+                    break;
+                }
+                
+                // 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->flags() & NodeHasVarArgs) {
+                    for (unsigned childIdx = node->firstChild(); childIdx < node->firstChild() + node->numChildren(); childIdx++)
+                        scoreBoard.useIfHasResult(m_graph.m_varArgChildren[childIdx]);
+                } else {
+                    scoreBoard.useIfHasResult(node->child1());
+                    scoreBoard.useIfHasResult(node->child2());
+                    scoreBoard.useIfHasResult(node->child3());
+                }
+
+                if (!node->hasResult())
+                    continue;
+
+                VirtualRegister virtualRegister = scoreBoard.allocate();
+                node->setVirtualRegister(virtualRegister);
+                // 'mustGenerate' nodes have their useCount artificially elevated,
+                // call use now to account for this.
+                if (node->mustGenerate())
+                    scoreBoard.use(node);
+            }
+            scoreBoard.assertClear();
+        }
+        
+        // Record the number of virtual registers we're using. This is used by calls
+        // to figure out where to put the parameters.
+        m_graph.m_nextMachineLocal = scoreBoard.highWatermark();
+
+        return true;
+    }
+};
+
+bool performVirtualRegisterAllocation(Graph& graph)
+{
+    SamplingRegion samplingRegion("DFG Virtual Register Allocation Phase");
+    return runPhase<VirtualRegisterAllocationPhase>(graph);
+}
+
+} } // namespace JSC::DFG
+
+#endif // ENABLE(DFG_JIT)