roland@7041: /*
roland@7041:  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
roland@7041:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
roland@7041:  *
roland@7041:  * This code is free software; you can redistribute it and/or modify it
roland@7041:  * under the terms of the GNU General Public License version 2 only, as
roland@7041:  * published by the Free Software Foundation.
roland@7041:  *
roland@7041:  * This code is distributed in the hope that it will be useful, but WITHOUT
roland@7041:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
roland@7041:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
roland@7041:  * version 2 for more details (a copy is included in the LICENSE file that
roland@7041:  * accompanied this code).
roland@7041:  *
roland@7041:  * You should have received a copy of the GNU General Public License version
roland@7041:  * 2 along with this work; if not, write to the Free Software Foundation,
roland@7041:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
roland@7041:  *
roland@7041:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
roland@7041:  * or visit www.oracle.com if you need additional information or have any
roland@7041:  * questions.
roland@7041:  *
roland@7041:  */
roland@7041: 
roland@7041: #ifndef SHARE_VM_OPTO_REPLACEDNODES_HPP
roland@7041: #define SHARE_VM_OPTO_REPLACEDNODES_HPP
roland@7041: 
roland@7041: #include "opto/connode.hpp"
roland@7041: 
roland@7041: // During parsing, when a node is "improved",
roland@7041: // GraphKit::replace_in_map() is called to update the current map so
roland@7041: // that the improved node is used from that point
roland@7041: // on. GraphKit::replace_in_map() doesn't operate on the callers maps
roland@7041: // and so some optimization opportunities may be lost. The
roland@7041: // ReplacedNodes class addresses that problem.
roland@7041: //
roland@7041: // A ReplacedNodes object is a list of pair of nodes. Every
roland@7041: // SafePointNode carries a ReplacedNodes object. Every time
roland@7041: // GraphKit::replace_in_map() is called, a new pair of nodes is pushed
roland@7041: // on the list of replaced nodes. When control flow paths merge, their
roland@7041: // replaced nodes are also merged. When parsing exits a method to
roland@7041: // return to a caller, the replaced nodes on the exit path are used to
roland@7041: // update the caller's map.
roland@7041: class ReplacedNodes VALUE_OBJ_CLASS_SPEC {
roland@7041:  private:
roland@7041:   class ReplacedNode VALUE_OBJ_CLASS_SPEC {
roland@7041:   private:
roland@7041:     Node* _initial;
roland@7041:     Node* _improved;
roland@7041:   public:
roland@7041:     ReplacedNode() : _initial(NULL), _improved(NULL) {}
roland@7041:     ReplacedNode(Node* initial, Node* improved) : _initial(initial), _improved(improved) {}
roland@7041:     Node* initial() const  { return _initial; }
roland@7041:     Node* improved() const { return _improved; }
roland@7041: 
roland@7041:     bool operator==(const ReplacedNode& other) {
roland@7041:       return _initial == other._initial && _improved == other._improved;
roland@7041:     }
roland@7041:   };
roland@7041:   GrowableArray<ReplacedNode>* _replaced_nodes;
roland@7041: 
roland@7041:   void allocate_if_necessary();
roland@7041:   bool has_node(const ReplacedNode& r) const;
roland@7041:   bool has_target_node(Node* n) const;
roland@7041: 
roland@7041:  public:
roland@7041:   ReplacedNodes()
roland@7041:     : _replaced_nodes(NULL) {}
roland@7041: 
roland@7041:   void clone();
roland@7041:   void record(Node* initial, Node* improved);
roland@7041:   void transfer_from(const ReplacedNodes& other, uint idx);
roland@7041:   void reset();
roland@7041:   void apply(Node* n);
roland@7041:   void merge_with(const ReplacedNodes& other);
roland@7041:   bool is_empty() const;
roland@7041:   void dump(outputStream *st) const;
roland@7041:   void apply(Compile* C, Node* ctl);
roland@7041: };
roland@7041: 
roland@7041: #endif // SHARE_VM_OPTO_REPLACEDNODES_HPP