1 /* 2 * Copyright (c) 2014, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_OPTO_OPAQUENODE_HPP 26 #define SHARE_VM_OPTO_OPAQUENODE_HPP 27 28 #include "opto/node.hpp" 29 #include "opto/opcodes.hpp" 30 31 //------------------------------Opaque1Node------------------------------------ 32 // A node to prevent unwanted optimizations. Allows constant folding. 33 // Stops value-numbering, Ideal calls or Identity functions. 34 class Opaque1Node : public Node { 35 virtual uint hash() const ; // { return NO_HASH; } 36 virtual uint cmp( const Node &n ) const; 37 public: 38 Opaque1Node( Compile* C, Node *n ) : Node(0,n) { 39 // Put it on the Macro nodes list to removed during macro nodes expansion. 40 init_flags(Flag_is_macro); 41 C->add_macro_node(this); 42 } 43 // Special version for the pre-loop to hold the original loop limit 44 // which is consumed by range check elimination. 45 Opaque1Node( Compile* C, Node *n, Node* orig_limit ) : Node(0,n,orig_limit) { 46 // Put it on the Macro nodes list to removed during macro nodes expansion. 47 init_flags(Flag_is_macro); 48 C->add_macro_node(this); 49 } 50 Node* original_loop_limit() { return req()==3 ? in(2) : NULL; } 51 virtual int Opcode() const; 52 virtual const Type *bottom_type() const { return TypeInt::INT; } 53 virtual Node *Identity( PhaseTransform *phase ); 54 }; 55 56 //------------------------------Opaque2Node------------------------------------ 57 // A node to prevent unwanted optimizations. Allows constant folding. Stops 58 // value-numbering, most Ideal calls or Identity functions. This Node is 59 // specifically designed to prevent the pre-increment value of a loop trip 60 // counter from being live out of the bottom of the loop (hence causing the 61 // pre- and post-increment values both being live and thus requiring an extra 62 // temp register and an extra move). If we "accidentally" optimize through 63 // this kind of a Node, we'll get slightly pessimal, but correct, code. Thus 64 // it's OK to be slightly sloppy on optimizations here. 65 class Opaque2Node : public Node { 66 virtual uint hash() const ; // { return NO_HASH; } 67 virtual uint cmp( const Node &n ) const; 68 public: 69 Opaque2Node( Compile* C, Node *n ) : Node(0,n) { 70 // Put it on the Macro nodes list to removed during macro nodes expansion. 71 init_flags(Flag_is_macro); 72 C->add_macro_node(this); 73 } 74 virtual int Opcode() const; 75 virtual const Type *bottom_type() const { return TypeInt::INT; } 76 }; 77 78 //------------------------------Opaque3Node------------------------------------ 79 // A node to prevent unwanted optimizations. Will be optimized only during 80 // macro nodes expansion. 81 class Opaque3Node : public Opaque2Node { 82 int _opt; // what optimization it was used for 83 public: 84 enum { RTM_OPT }; 85 Opaque3Node(Compile* C, Node *n, int opt) : Opaque2Node(C, n), _opt(opt) {} 86 virtual int Opcode() const; 87 bool rtm_opt() const { return (_opt == RTM_OPT); } 88 }; 89 90 #endif // SHARE_VM_OPTO_OPAQUENODE_HPP 91