hotspot/src/share/vm/opto/rootnode.hpp
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0:fd16c54261b3 1:489c9b5090e2
       
     1 /*
       
     2  * Copyright 1997-2005 Sun Microsystems, Inc.  All Rights Reserved.
       
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       
     4  *
       
     5  * This code is free software; you can redistribute it and/or modify it
       
     6  * under the terms of the GNU General Public License version 2 only, as
       
     7  * published by the Free Software Foundation.
       
     8  *
       
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
       
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
       
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
       
    12  * version 2 for more details (a copy is included in the LICENSE file that
       
    13  * accompanied this code).
       
    14  *
       
    15  * You should have received a copy of the GNU General Public License version
       
    16  * 2 along with this work; if not, write to the Free Software Foundation,
       
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
       
    18  *
       
    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
       
    20  * CA 95054 USA or visit www.sun.com if you need additional information or
       
    21  * have any questions.
       
    22  *
       
    23  */
       
    24 
       
    25 //------------------------------RootNode---------------------------------------
       
    26 // The one-and-only before-all-else and after-all-else RootNode.  The RootNode
       
    27 // represents what happens if the user runs the whole program repeatedly.  The
       
    28 // RootNode produces the initial values of I/O and memory for the program or
       
    29 // procedure start.
       
    30 class RootNode : public LoopNode {
       
    31 public:
       
    32   RootNode( ) : LoopNode(0,0) {
       
    33     init_class_id(Class_Root);
       
    34     del_req(2);
       
    35     del_req(1);
       
    36   }
       
    37   virtual int   Opcode() const;
       
    38   virtual const Node *is_block_proj() const { return this; }
       
    39   virtual const Type *bottom_type() const { return Type::BOTTOM; }
       
    40   virtual Node *Identity( PhaseTransform *phase ) { return this; }
       
    41   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
       
    42   virtual const Type *Value( PhaseTransform *phase ) const { return Type::BOTTOM; }
       
    43 };
       
    44 
       
    45 //------------------------------HaltNode---------------------------------------
       
    46 // Throw an exception & die
       
    47 class HaltNode : public Node {
       
    48 public:
       
    49   HaltNode( Node *ctrl, Node *frameptr );
       
    50   virtual int Opcode() const;
       
    51   virtual bool  pinned() const { return true; };
       
    52   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
       
    53   virtual const Type *Value( PhaseTransform *phase ) const;
       
    54   virtual const Type *bottom_type() const;
       
    55   virtual bool  is_CFG() const { return true; }
       
    56   virtual uint hash() const { return NO_HASH; }  // CFG nodes do not hash
       
    57   virtual bool depends_only_on_test() const { return false; }
       
    58   virtual const Node *is_block_proj() const { return this; }
       
    59   virtual const RegMask &out_RegMask() const;
       
    60   virtual uint ideal_reg() const { return NotAMachineReg; }
       
    61   virtual uint match_edge(uint idx) const { return 0; }
       
    62 };