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1 /* |
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2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 * |
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23 */ |
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24 |
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25 #ifndef SHARE_VM_OPTO_CFGNODE_HPP |
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26 #define SHARE_VM_OPTO_CFGNODE_HPP |
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27 |
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28 #include "opto/multnode.hpp" |
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29 #include "opto/node.hpp" |
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30 #include "opto/opcodes.hpp" |
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31 #include "opto/type.hpp" |
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32 |
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33 // Portions of code courtesy of Clifford Click |
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34 |
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35 // Optimization - Graph Style |
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36 |
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37 class Matcher; |
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38 class Node; |
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39 class RegionNode; |
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40 class TypeNode; |
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41 class PhiNode; |
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42 class GotoNode; |
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43 class MultiNode; |
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44 class MultiBranchNode; |
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45 class IfNode; |
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46 class PCTableNode; |
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47 class JumpNode; |
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48 class CatchNode; |
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49 class NeverBranchNode; |
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50 class ProjNode; |
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51 class CProjNode; |
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52 class IfTrueNode; |
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53 class IfFalseNode; |
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54 class CatchProjNode; |
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55 class JProjNode; |
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56 class JumpProjNode; |
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57 class SCMemProjNode; |
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58 class PhaseIdealLoop; |
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59 |
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60 //------------------------------RegionNode------------------------------------- |
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61 // The class of RegionNodes, which can be mapped to basic blocks in the |
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62 // program. Their inputs point to Control sources. PhiNodes (described |
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63 // below) have an input point to a RegionNode. Merged data inputs to PhiNodes |
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64 // correspond 1-to-1 with RegionNode inputs. The zero input of a PhiNode is |
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65 // the RegionNode, and the zero input of the RegionNode is itself. |
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66 class RegionNode : public Node { |
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67 public: |
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68 // Node layout (parallels PhiNode): |
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69 enum { Region, // Generally points to self. |
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70 Control // Control arcs are [1..len) |
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71 }; |
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72 |
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73 RegionNode( uint required ) : Node(required) { |
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74 init_class_id(Class_Region); |
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75 init_req(0,this); |
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76 } |
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77 |
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78 Node* is_copy() const { |
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79 const Node* r = _in[Region]; |
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80 if (r == NULL) |
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81 return nonnull_req(); |
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82 return NULL; // not a copy! |
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83 } |
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84 PhiNode* has_phi() const; // returns an arbitrary phi user, or NULL |
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85 PhiNode* has_unique_phi() const; // returns the unique phi user, or NULL |
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86 // Is this region node unreachable from root? |
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87 bool is_unreachable_region(PhaseGVN *phase) const; |
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88 virtual int Opcode() const; |
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89 virtual bool pinned() const { return (const Node *)in(0) == this; } |
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90 virtual bool is_CFG () const { return true; } |
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91 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash |
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92 virtual bool depends_only_on_test() const { return false; } |
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93 virtual const Type *bottom_type() const { return Type::CONTROL; } |
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94 virtual const Type *Value( PhaseTransform *phase ) const; |
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95 virtual Node *Identity( PhaseTransform *phase ); |
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96 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); |
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97 virtual const RegMask &out_RegMask() const; |
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98 bool try_clean_mem_phi(PhaseGVN *phase); |
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99 }; |
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100 |
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101 //------------------------------JProjNode-------------------------------------- |
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102 // jump projection for node that produces multiple control-flow paths |
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103 class JProjNode : public ProjNode { |
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104 public: |
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105 JProjNode( Node* ctrl, uint idx ) : ProjNode(ctrl,idx) {} |
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106 virtual int Opcode() const; |
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107 virtual bool is_CFG() const { return true; } |
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108 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash |
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109 virtual const Node* is_block_proj() const { return in(0); } |
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110 virtual const RegMask& out_RegMask() const; |
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111 virtual uint ideal_reg() const { return 0; } |
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112 }; |
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113 |
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114 //------------------------------PhiNode---------------------------------------- |
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115 // PhiNodes merge values from different Control paths. Slot 0 points to the |
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116 // controlling RegionNode. Other slots map 1-for-1 with incoming control flow |
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117 // paths to the RegionNode. For speed reasons (to avoid another pass) we |
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118 // can turn PhiNodes into copys in-place by NULL'ing out their RegionNode |
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119 // input in slot 0. |
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120 class PhiNode : public TypeNode { |
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121 const TypePtr* const _adr_type; // non-null only for Type::MEMORY nodes. |
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122 const int _inst_id; // Instance id of the memory slice. |
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123 const int _inst_index; // Alias index of the instance memory slice. |
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124 // Array elements references have the same alias_idx but different offset. |
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125 const int _inst_offset; // Offset of the instance memory slice. |
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126 // Size is bigger to hold the _adr_type field. |
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127 virtual uint hash() const; // Check the type |
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128 virtual uint cmp( const Node &n ) const; |
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129 virtual uint size_of() const { return sizeof(*this); } |
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130 |
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131 // Determine if CMoveNode::is_cmove_id can be used at this join point. |
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132 Node* is_cmove_id(PhaseTransform* phase, int true_path); |
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133 |
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134 public: |
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135 // Node layout (parallels RegionNode): |
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136 enum { Region, // Control input is the Phi's region. |
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137 Input // Input values are [1..len) |
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138 }; |
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139 |
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140 PhiNode( Node *r, const Type *t, const TypePtr* at = NULL, |
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141 const int iid = TypeOopPtr::InstanceTop, |
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142 const int iidx = Compile::AliasIdxTop, |
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143 const int ioffs = Type::OffsetTop ) |
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144 : TypeNode(t,r->req()), |
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145 _adr_type(at), |
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146 _inst_id(iid), |
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147 _inst_index(iidx), |
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148 _inst_offset(ioffs) |
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149 { |
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150 init_class_id(Class_Phi); |
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151 init_req(0, r); |
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152 verify_adr_type(); |
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153 } |
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154 // create a new phi with in edges matching r and set (initially) to x |
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155 static PhiNode* make( Node* r, Node* x ); |
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156 // extra type arguments override the new phi's bottom_type and adr_type |
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157 static PhiNode* make( Node* r, Node* x, const Type *t, const TypePtr* at = NULL ); |
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158 // create a new phi with narrowed memory type |
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159 PhiNode* slice_memory(const TypePtr* adr_type) const; |
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160 PhiNode* split_out_instance(const TypePtr* at, PhaseIterGVN *igvn) const; |
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161 // like make(r, x), but does not initialize the in edges to x |
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162 static PhiNode* make_blank( Node* r, Node* x ); |
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163 |
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164 // Accessors |
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165 RegionNode* region() const { Node* r = in(Region); assert(!r || r->is_Region(), ""); return (RegionNode*)r; } |
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166 |
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167 Node* is_copy() const { |
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168 // The node is a real phi if _in[0] is a Region node. |
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169 DEBUG_ONLY(const Node* r = _in[Region];) |
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170 assert(r != NULL && r->is_Region(), "Not valid control"); |
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171 return NULL; // not a copy! |
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172 } |
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173 |
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174 bool is_tripcount() const; |
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175 |
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176 // Determine a unique non-trivial input, if any. |
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177 // Ignore casts if it helps. Return NULL on failure. |
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178 Node* unique_input(PhaseTransform *phase); |
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179 |
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180 // Check for a simple dead loop. |
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181 enum LoopSafety { Safe = 0, Unsafe, UnsafeLoop }; |
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182 LoopSafety simple_data_loop_check(Node *in) const; |
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183 // Is it unsafe data loop? It becomes a dead loop if this phi node removed. |
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184 bool is_unsafe_data_reference(Node *in) const; |
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185 int is_diamond_phi(bool check_control_only = false) const; |
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186 virtual int Opcode() const; |
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187 virtual bool pinned() const { return in(0) != 0; } |
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188 virtual const TypePtr *adr_type() const { verify_adr_type(true); return _adr_type; } |
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189 |
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190 const int inst_id() const { return _inst_id; } |
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191 const int inst_index() const { return _inst_index; } |
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192 const int inst_offset() const { return _inst_offset; } |
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193 bool is_same_inst_field(const Type* tp, int id, int index, int offset) { |
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194 return type()->basic_type() == tp->basic_type() && |
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195 inst_id() == id && |
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196 inst_index() == index && |
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197 inst_offset() == offset && |
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198 type()->higher_equal(tp); |
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199 } |
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200 |
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201 virtual const Type *Value( PhaseTransform *phase ) const; |
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202 virtual Node *Identity( PhaseTransform *phase ); |
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203 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); |
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204 virtual const RegMask &out_RegMask() const; |
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205 virtual const RegMask &in_RegMask(uint) const; |
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206 #ifndef PRODUCT |
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207 virtual void dump_spec(outputStream *st) const; |
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208 #endif |
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209 #ifdef ASSERT |
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210 void verify_adr_type(VectorSet& visited, const TypePtr* at) const; |
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211 void verify_adr_type(bool recursive = false) const; |
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212 #else //ASSERT |
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213 void verify_adr_type(bool recursive = false) const {} |
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214 #endif //ASSERT |
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215 }; |
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216 |
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217 //------------------------------GotoNode--------------------------------------- |
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218 // GotoNodes perform direct branches. |
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219 class GotoNode : public Node { |
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220 public: |
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221 GotoNode( Node *control ) : Node(control) {} |
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222 virtual int Opcode() const; |
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223 virtual bool pinned() const { return true; } |
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224 virtual bool is_CFG() const { return true; } |
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225 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash |
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226 virtual const Node *is_block_proj() const { return this; } |
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227 virtual bool depends_only_on_test() const { return false; } |
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228 virtual const Type *bottom_type() const { return Type::CONTROL; } |
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229 virtual const Type *Value( PhaseTransform *phase ) const; |
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230 virtual Node *Identity( PhaseTransform *phase ); |
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231 virtual const RegMask &out_RegMask() const; |
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232 }; |
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233 |
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234 //------------------------------CProjNode-------------------------------------- |
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235 // control projection for node that produces multiple control-flow paths |
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236 class CProjNode : public ProjNode { |
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237 public: |
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238 CProjNode( Node *ctrl, uint idx ) : ProjNode(ctrl,idx) {} |
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239 virtual int Opcode() const; |
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240 virtual bool is_CFG() const { return true; } |
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241 virtual uint hash() const { return NO_HASH; } // CFG nodes do not hash |
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242 virtual const Node *is_block_proj() const { return in(0); } |
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243 virtual const RegMask &out_RegMask() const; |
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244 virtual uint ideal_reg() const { return 0; } |
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245 }; |
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246 |
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247 //---------------------------MultiBranchNode----------------------------------- |
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248 // This class defines a MultiBranchNode, a MultiNode which yields multiple |
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249 // control values. These are distinguished from other types of MultiNodes |
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250 // which yield multiple values, but control is always and only projection #0. |
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251 class MultiBranchNode : public MultiNode { |
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252 public: |
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253 MultiBranchNode( uint required ) : MultiNode(required) { |
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254 init_class_id(Class_MultiBranch); |
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255 } |
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256 // returns required number of users to be well formed. |
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257 virtual int required_outcnt() const = 0; |
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258 }; |
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259 |
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260 //------------------------------IfNode----------------------------------------- |
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261 // Output selected Control, based on a boolean test |
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262 class IfNode : public MultiBranchNode { |
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263 // Size is bigger to hold the probability field. However, _prob does not |
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264 // change the semantics so it does not appear in the hash & cmp functions. |
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265 virtual uint size_of() const { return sizeof(*this); } |
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266 public: |
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267 |
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268 // Degrees of branch prediction probability by order of magnitude: |
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269 // PROB_UNLIKELY_1e(N) is a 1 in 1eN chance. |
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270 // PROB_LIKELY_1e(N) is a 1 - PROB_UNLIKELY_1e(N) |
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271 #define PROB_UNLIKELY_MAG(N) (1e- ## N ## f) |
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272 #define PROB_LIKELY_MAG(N) (1.0f-PROB_UNLIKELY_MAG(N)) |
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273 |
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274 // Maximum and minimum branch prediction probabilties |
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275 // 1 in 1,000,000 (magnitude 6) |
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276 // |
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277 // Although PROB_NEVER == PROB_MIN and PROB_ALWAYS == PROB_MAX |
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278 // they are used to distinguish different situations: |
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279 // |
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280 // The name PROB_MAX (PROB_MIN) is for probabilities which correspond to |
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281 // very likely (unlikely) but with a concrete possibility of a rare |
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282 // contrary case. These constants would be used for pinning |
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283 // measurements, and as measures for assertions that have high |
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284 // confidence, but some evidence of occasional failure. |
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285 // |
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286 // The name PROB_ALWAYS (PROB_NEVER) is to stand for situations for which |
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287 // there is no evidence at all that the contrary case has ever occurred. |
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288 |
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289 #define PROB_NEVER PROB_UNLIKELY_MAG(6) |
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290 #define PROB_ALWAYS PROB_LIKELY_MAG(6) |
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291 |
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292 #define PROB_MIN PROB_UNLIKELY_MAG(6) |
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293 #define PROB_MAX PROB_LIKELY_MAG(6) |
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294 |
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295 // Static branch prediction probabilities |
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296 // 1 in 10 (magnitude 1) |
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297 #define PROB_STATIC_INFREQUENT PROB_UNLIKELY_MAG(1) |
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298 #define PROB_STATIC_FREQUENT PROB_LIKELY_MAG(1) |
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299 |
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300 // Fair probability 50/50 |
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301 #define PROB_FAIR (0.5f) |
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302 |
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303 // Unknown probability sentinel |
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304 #define PROB_UNKNOWN (-1.0f) |
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305 |
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306 // Probability "constructors", to distinguish as a probability any manifest |
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307 // constant without a names |
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308 #define PROB_LIKELY(x) ((float) (x)) |
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309 #define PROB_UNLIKELY(x) (1.0f - (float)(x)) |
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310 |
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311 // Other probabilities in use, but without a unique name, are documented |
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312 // here for lack of a better place: |
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313 // |
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314 // 1 in 1000 probabilities (magnitude 3): |
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315 // threshold for converting to conditional move |
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316 // likelihood of null check failure if a null HAS been seen before |
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317 // likelihood of slow path taken in library calls |
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318 // |
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319 // 1 in 10,000 probabilities (magnitude 4): |
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320 // threshold for making an uncommon trap probability more extreme |
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321 // threshold for for making a null check implicit |
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322 // likelihood of needing a gc if eden top moves during an allocation |
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323 // likelihood of a predicted call failure |
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324 // |
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325 // 1 in 100,000 probabilities (magnitude 5): |
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326 // threshold for ignoring counts when estimating path frequency |
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327 // likelihood of FP clipping failure |
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328 // likelihood of catching an exception from a try block |
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329 // likelihood of null check failure if a null has NOT been seen before |
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330 // |
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331 // Magic manifest probabilities such as 0.83, 0.7, ... can be found in |
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332 // gen_subtype_check() and catch_inline_exceptions(). |
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333 |
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334 float _prob; // Probability of true path being taken. |
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335 float _fcnt; // Frequency counter |
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336 IfNode( Node *control, Node *b, float p, float fcnt ) |
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337 : MultiBranchNode(2), _prob(p), _fcnt(fcnt) { |
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338 init_class_id(Class_If); |
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339 init_req(0,control); |
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340 init_req(1,b); |
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341 } |
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342 virtual int Opcode() const; |
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343 virtual bool pinned() const { return true; } |
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344 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; } |
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345 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); |
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346 virtual const Type *Value( PhaseTransform *phase ) const; |
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347 virtual int required_outcnt() const { return 2; } |
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348 virtual const RegMask &out_RegMask() const; |
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349 void dominated_by(Node* prev_dom, PhaseIterGVN* igvn); |
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350 int is_range_check(Node* &range, Node* &index, jint &offset); |
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351 Node* fold_compares(PhaseGVN* phase); |
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352 static Node* up_one_dom(Node* curr, bool linear_only = false); |
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353 |
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354 // Takes the type of val and filters it through the test represented |
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355 // by if_proj and returns a more refined type if one is produced. |
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356 // Returns NULL is it couldn't improve the type. |
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357 static const TypeInt* filtered_int_type(PhaseGVN* phase, Node* val, Node* if_proj); |
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358 |
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359 #ifndef PRODUCT |
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360 virtual void dump_spec(outputStream *st) const; |
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361 #endif |
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362 }; |
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363 |
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364 class IfTrueNode : public CProjNode { |
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365 public: |
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366 IfTrueNode( IfNode *ifnode ) : CProjNode(ifnode,1) { |
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367 init_class_id(Class_IfTrue); |
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368 } |
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369 virtual int Opcode() const; |
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370 virtual Node *Identity( PhaseTransform *phase ); |
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371 }; |
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372 |
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373 class IfFalseNode : public CProjNode { |
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374 public: |
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375 IfFalseNode( IfNode *ifnode ) : CProjNode(ifnode,0) { |
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376 init_class_id(Class_IfFalse); |
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377 } |
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378 virtual int Opcode() const; |
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379 virtual Node *Identity( PhaseTransform *phase ); |
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380 }; |
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381 |
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382 |
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383 //------------------------------PCTableNode------------------------------------ |
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384 // Build an indirect branch table. Given a control and a table index, |
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385 // control is passed to the Projection matching the table index. Used to |
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386 // implement switch statements and exception-handling capabilities. |
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387 // Undefined behavior if passed-in index is not inside the table. |
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388 class PCTableNode : public MultiBranchNode { |
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389 virtual uint hash() const; // Target count; table size |
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390 virtual uint cmp( const Node &n ) const; |
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391 virtual uint size_of() const { return sizeof(*this); } |
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392 |
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393 public: |
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394 const uint _size; // Number of targets |
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395 |
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396 PCTableNode( Node *ctrl, Node *idx, uint size ) : MultiBranchNode(2), _size(size) { |
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397 init_class_id(Class_PCTable); |
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398 init_req(0, ctrl); |
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399 init_req(1, idx); |
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400 } |
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401 virtual int Opcode() const; |
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402 virtual const Type *Value( PhaseTransform *phase ) const; |
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403 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); |
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404 virtual const Type *bottom_type() const; |
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405 virtual bool pinned() const { return true; } |
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406 virtual int required_outcnt() const { return _size; } |
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407 }; |
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408 |
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409 //------------------------------JumpNode--------------------------------------- |
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410 // Indirect branch. Uses PCTable above to implement a switch statement. |
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411 // It emits as a table load and local branch. |
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412 class JumpNode : public PCTableNode { |
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413 public: |
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414 JumpNode( Node* control, Node* switch_val, uint size) : PCTableNode(control, switch_val, size) { |
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415 init_class_id(Class_Jump); |
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416 } |
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417 virtual int Opcode() const; |
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418 virtual const RegMask& out_RegMask() const; |
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419 virtual const Node* is_block_proj() const { return this; } |
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420 }; |
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421 |
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422 class JumpProjNode : public JProjNode { |
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423 virtual uint hash() const; |
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424 virtual uint cmp( const Node &n ) const; |
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425 virtual uint size_of() const { return sizeof(*this); } |
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426 |
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427 private: |
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428 const int _dest_bci; |
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429 const uint _proj_no; |
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430 const int _switch_val; |
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431 public: |
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432 JumpProjNode(Node* jumpnode, uint proj_no, int dest_bci, int switch_val) |
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433 : JProjNode(jumpnode, proj_no), _dest_bci(dest_bci), _proj_no(proj_no), _switch_val(switch_val) { |
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434 init_class_id(Class_JumpProj); |
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435 } |
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436 |
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437 virtual int Opcode() const; |
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438 virtual const Type* bottom_type() const { return Type::CONTROL; } |
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439 int dest_bci() const { return _dest_bci; } |
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440 int switch_val() const { return _switch_val; } |
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441 uint proj_no() const { return _proj_no; } |
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442 #ifndef PRODUCT |
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443 virtual void dump_spec(outputStream *st) const; |
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444 #endif |
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445 }; |
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446 |
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447 //------------------------------CatchNode-------------------------------------- |
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448 // Helper node to fork exceptions. "Catch" catches any exceptions thrown by |
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449 // a just-prior call. Looks like a PCTableNode but emits no code - just the |
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450 // table. The table lookup and branch is implemented by RethrowNode. |
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451 class CatchNode : public PCTableNode { |
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452 public: |
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453 CatchNode( Node *ctrl, Node *idx, uint size ) : PCTableNode(ctrl,idx,size){ |
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454 init_class_id(Class_Catch); |
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455 } |
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456 virtual int Opcode() const; |
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457 virtual const Type *Value( PhaseTransform *phase ) const; |
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458 }; |
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459 |
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460 // CatchProjNode controls which exception handler is targetted after a call. |
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461 // It is passed in the bci of the target handler, or no_handler_bci in case |
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462 // the projection doesn't lead to an exception handler. |
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463 class CatchProjNode : public CProjNode { |
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464 virtual uint hash() const; |
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465 virtual uint cmp( const Node &n ) const; |
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466 virtual uint size_of() const { return sizeof(*this); } |
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467 |
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468 private: |
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469 const int _handler_bci; |
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470 |
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471 public: |
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472 enum { |
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473 fall_through_index = 0, // the fall through projection index |
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474 catch_all_index = 1, // the projection index for catch-alls |
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475 no_handler_bci = -1 // the bci for fall through or catch-all projs |
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476 }; |
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477 |
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478 CatchProjNode(Node* catchnode, uint proj_no, int handler_bci) |
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479 : CProjNode(catchnode, proj_no), _handler_bci(handler_bci) { |
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480 init_class_id(Class_CatchProj); |
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481 assert(proj_no != fall_through_index || handler_bci < 0, "fall through case must have bci < 0"); |
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482 } |
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483 |
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484 virtual int Opcode() const; |
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485 virtual Node *Identity( PhaseTransform *phase ); |
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486 virtual const Type *bottom_type() const { return Type::CONTROL; } |
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487 int handler_bci() const { return _handler_bci; } |
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488 bool is_handler_proj() const { return _handler_bci >= 0; } |
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489 #ifndef PRODUCT |
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490 virtual void dump_spec(outputStream *st) const; |
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491 #endif |
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492 }; |
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493 |
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494 |
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495 //---------------------------------CreateExNode-------------------------------- |
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496 // Helper node to create the exception coming back from a call |
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497 class CreateExNode : public TypeNode { |
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498 public: |
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499 CreateExNode(const Type* t, Node* control, Node* i_o) : TypeNode(t, 2) { |
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500 init_req(0, control); |
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501 init_req(1, i_o); |
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502 } |
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503 virtual int Opcode() const; |
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504 virtual Node *Identity( PhaseTransform *phase ); |
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505 virtual bool pinned() const { return true; } |
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506 uint match_edge(uint idx) const { return 0; } |
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507 virtual uint ideal_reg() const { return Op_RegP; } |
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508 }; |
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509 |
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510 //------------------------------NeverBranchNode------------------------------- |
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511 // The never-taken branch. Used to give the appearance of exiting infinite |
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512 // loops to those algorithms that like all paths to be reachable. Encodes |
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513 // empty. |
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514 class NeverBranchNode : public MultiBranchNode { |
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515 public: |
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516 NeverBranchNode( Node *ctrl ) : MultiBranchNode(1) { init_req(0,ctrl); } |
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517 virtual int Opcode() const; |
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518 virtual bool pinned() const { return true; }; |
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519 virtual const Type *bottom_type() const { return TypeTuple::IFBOTH; } |
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520 virtual const Type *Value( PhaseTransform *phase ) const; |
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521 virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); |
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522 virtual int required_outcnt() const { return 2; } |
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523 virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const { } |
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524 virtual uint size(PhaseRegAlloc *ra_) const { return 0; } |
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525 #ifndef PRODUCT |
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526 virtual void format( PhaseRegAlloc *, outputStream *st ) const; |
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527 #endif |
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528 }; |
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529 |
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530 #endif // SHARE_VM_OPTO_CFGNODE_HPP |