src/share/vm/opto/rootnode.hpp

/*
 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
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 */

#ifndef SHARE_VM_OPTO_ROOTNODE_HPP
#define SHARE_VM_OPTO_ROOTNODE_HPP

#include "opto/loopnode.hpp"

//------------------------------RootNode---------------------------------------
// The one-and-only before-all-else and after-all-else RootNode.  The RootNode
// represents what happens if the user runs the whole program repeatedly.  The
// RootNode produces the initial values of I/O and memory for the program or
// procedure start.
class RootNode : public LoopNode {
public:
  RootNode( ) : LoopNode(0,0) {
    init_class_id(Class_Root);
    del_req(2);
    del_req(1);
  }
  virtual int   Opcode() const;
  virtual const Node *is_block_proj() const { return this; }
  virtual const Type *bottom_type() const { return Type::BOTTOM; }
  virtual Node *Identity( PhaseTransform *phase ) { return this; }
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
  virtual const Type *Value( PhaseTransform *phase ) const { return Type::BOTTOM; }
};

//------------------------------HaltNode---------------------------------------
// Throw an exception & die
class HaltNode : public Node {
public:
  HaltNode( Node *ctrl, Node *frameptr );
  virtual int Opcode() const;
  virtual bool  pinned() const { return true; };
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
  virtual const Type *Value( PhaseTransform *phase ) const;
  virtual const Type *bottom_type() const;
  virtual bool  is_CFG() const { return true; }
  virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash
  virtual bool depends_only_on_test() const { return false; }
  virtual const Node *is_block_proj() const { return this; }
  virtual const RegMask &out_RegMask() const;
  virtual uint ideal_reg() const { return NotAMachineReg; }
  virtual uint match_edge(uint idx) const { return 0; }
};

#endif // SHARE_VM_OPTO_ROOTNODE_HPP