/*+
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 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.+
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.+
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 *+
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 * This code is free software; you can redistribute it and/or modify it+
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 * under the terms of the GNU General Public License version 2 only, as+
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 * published by the Free Software Foundation.+
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 *+
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 * This code is distributed in the hope that it will be useful, but WITHOUT+
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or+
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License+
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 * version 2 for more details (a copy is included in the LICENSE file that+
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 * accompanied this code).+
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 *+
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 * You should have received a copy of the GNU General Public License version+
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 * 2 along with this work; if not, write to the Free Software Foundation,+
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.+
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 *+
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA+
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 * or visit www.oracle.com if you need additional information or have any+
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 * questions.+
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 *+
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 */+
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+
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#ifndef SHARE_VM_OPTO_REPLACEDNODES_HPP+
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#define SHARE_VM_OPTO_REPLACEDNODES_HPP+
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+
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#include "opto/connode.hpp"+
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+
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// During parsing, when a node is "improved",+
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// GraphKit::replace_in_map() is called to update the current map so+
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// that the improved node is used from that point+
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// on. GraphKit::replace_in_map() doesn't operate on the callers maps+
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// and so some optimization opportunities may be lost. The+
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// ReplacedNodes class addresses that problem.+
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//+
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// A ReplacedNodes object is a list of pair of nodes. Every+
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// SafePointNode carries a ReplacedNodes object. Every time+
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// GraphKit::replace_in_map() is called, a new pair of nodes is pushed+
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// on the list of replaced nodes. When control flow paths merge, their+
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// replaced nodes are also merged. When parsing exits a method to+
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// return to a caller, the replaced nodes on the exit path are used to+
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// update the caller's map.+
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class ReplacedNodes VALUE_OBJ_CLASS_SPEC {+
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 private:+
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  class ReplacedNode VALUE_OBJ_CLASS_SPEC {+
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  private:+
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    Node* _initial;+
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    Node* _improved;+
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  public:+
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    ReplacedNode() : _initial(NULL), _improved(NULL) {}+
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    ReplacedNode(Node* initial, Node* improved) : _initial(initial), _improved(improved) {}+
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    Node* initial() const  { return _initial; }+
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    Node* improved() const { return _improved; }+
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+
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    bool operator==(const ReplacedNode& other) {+
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      return _initial == other._initial && _improved == other._improved;+
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    }+
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  };+
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  GrowableArray<ReplacedNode>* _replaced_nodes;+
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+
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  void allocate_if_necessary();+
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  bool has_node(const ReplacedNode& r) const;+
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  bool has_target_node(Node* n) const;+
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+
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 public:+
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  ReplacedNodes()+
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    : _replaced_nodes(NULL) {}+
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+
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  void clone();+
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  void record(Node* initial, Node* improved);+
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  void transfer_from(const ReplacedNodes& other, uint idx);+
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  void reset();+
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  void apply(Node* n);+
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  void merge_with(const ReplacedNodes& other);+
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  bool is_empty() const;+
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  void dump(outputStream *st) const;+
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  void apply(Compile* C, Node* ctl);+
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};+
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+
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#endif // SHARE_VM_OPTO_REPLACEDNODES_HPP+
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