0
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1 /*
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2 * Copyright 1998-2004 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 // This file defines the IndexSet class, a set of sparse integer indices.
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26 // This data structure is used by the compiler in its liveness analysis and
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27 // during register allocation. It also defines an iterator for this class.
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28
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29 #include "incls/_precompiled.incl"
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30 #include "incls/_indexSet.cpp.incl"
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31
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32 //-------------------------------- Initializations ------------------------------
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33
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34 IndexSet::BitBlock IndexSet::_empty_block = IndexSet::BitBlock();
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35
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36 #ifdef ASSERT
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37 // Initialize statistics counters
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38 uint IndexSet::_alloc_new = 0;
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39 uint IndexSet::_alloc_total = 0;
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40
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41 long IndexSet::_total_bits = 0;
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42 long IndexSet::_total_used_blocks = 0;
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43 long IndexSet::_total_unused_blocks = 0;
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44
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45 // Per set, or all sets operation tracing
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46 int IndexSet::_serial_count = 1;
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47 #endif
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48
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49 // What is the first set bit in a 5 bit integer?
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50 const byte IndexSetIterator::_first_bit[32] = {
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51 0, 0, 1, 0,
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52 2, 0, 1, 0,
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53 3, 0, 1, 0,
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54 2, 0, 1, 0,
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55 4, 0, 1, 0,
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56 2, 0, 1, 0,
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57 3, 0, 1, 0,
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58 2, 0, 1, 0
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59 };
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60
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61 // What is the second set bit in a 5 bit integer?
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62 const byte IndexSetIterator::_second_bit[32] = {
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63 5, 5, 5, 1,
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64 5, 2, 2, 1,
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65 5, 3, 3, 1,
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66 3, 2, 2, 1,
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67 5, 4, 4, 1,
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68 4, 2, 2, 1,
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69 4, 3, 3, 1,
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70 3, 2, 2, 1
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71 };
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72
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73 // I tried implementing the IndexSetIterator with a window_size of 8 and
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74 // didn't seem to get a noticeable speedup. I am leaving in the tables
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75 // in case we want to switch back.
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76
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77 /*const byte IndexSetIterator::_first_bit[256] = {
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78 8, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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79 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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80 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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81 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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82 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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83 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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84 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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85 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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86 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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87 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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88 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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89 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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90 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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91 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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92 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
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93 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0
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94 };
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95
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96 const byte IndexSetIterator::_second_bit[256] = {
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97 8, 8, 8, 1, 8, 2, 2, 1, 8, 3, 3, 1, 3, 2, 2, 1,
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98 8, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1,
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99 8, 5, 5, 1, 5, 2, 2, 1, 5, 3, 3, 1, 3, 2, 2, 1,
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100 5, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1,
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101 8, 6, 6, 1, 6, 2, 2, 1, 6, 3, 3, 1, 3, 2, 2, 1,
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102 6, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1,
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103 6, 5, 5, 1, 5, 2, 2, 1, 5, 3, 3, 1, 3, 2, 2, 1,
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104 5, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1,
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105 8, 7, 7, 1, 7, 2, 2, 1, 7, 3, 3, 1, 3, 2, 2, 1,
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106 7, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1,
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107 7, 5, 5, 1, 5, 2, 2, 1, 5, 3, 3, 1, 3, 2, 2, 1,
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108 5, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1,
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109 7, 6, 6, 1, 6, 2, 2, 1, 6, 3, 3, 1, 3, 2, 2, 1,
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110 6, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1,
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111 6, 5, 5, 1, 5, 2, 2, 1, 5, 3, 3, 1, 3, 2, 2, 1,
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112 5, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1
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113 };*/
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114
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115 //---------------------------- IndexSet::populate_free_list() -----------------------------
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116 // Populate the free BitBlock list with a batch of BitBlocks. The BitBlocks
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117 // are 32 bit aligned.
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118
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119 void IndexSet::populate_free_list() {
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120 Compile *compile = Compile::current();
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121 BitBlock *free = (BitBlock*)compile->indexSet_free_block_list();
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122
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123 char *mem = (char*)arena()->Amalloc_4(sizeof(BitBlock) *
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124 bitblock_alloc_chunk_size + 32);
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125
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126 // Align the pointer to a 32 bit boundary.
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127 BitBlock *new_blocks = (BitBlock*)(((uintptr_t)mem + 32) & ~0x001F);
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128
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129 // Add the new blocks to the free list.
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130 for (int i = 0; i < bitblock_alloc_chunk_size; i++) {
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131 new_blocks->set_next(free);
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132 free = new_blocks;
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133 new_blocks++;
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134 }
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135
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136 compile->set_indexSet_free_block_list(free);
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137
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138 #ifdef ASSERT
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139 if (CollectIndexSetStatistics) {
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140 _alloc_new += bitblock_alloc_chunk_size;
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141 }
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142 #endif
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143 }
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144
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145
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146 //---------------------------- IndexSet::alloc_block() ------------------------
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147 // Allocate a BitBlock from the free list. If the free list is empty,
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148 // prime it.
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149
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150 IndexSet::BitBlock *IndexSet::alloc_block() {
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151 #ifdef ASSERT
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152 if (CollectIndexSetStatistics) {
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153 _alloc_total++;
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154 }
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155 #endif
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156 Compile *compile = Compile::current();
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157 BitBlock* free_list = (BitBlock*)compile->indexSet_free_block_list();
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158 if (free_list == NULL) {
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159 populate_free_list();
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160 free_list = (BitBlock*)compile->indexSet_free_block_list();
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161 }
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162 BitBlock *block = free_list;
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163 compile->set_indexSet_free_block_list(block->next());
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164
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165 block->clear();
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166 return block;
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167 }
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168
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169 //---------------------------- IndexSet::alloc_block_containing() -------------
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170 // Allocate a new BitBlock and put it into the position in the _blocks array
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171 // corresponding to element.
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172
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173 IndexSet::BitBlock *IndexSet::alloc_block_containing(uint element) {
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174 BitBlock *block = alloc_block();
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175 uint bi = get_block_index(element);
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176 _blocks[bi] = block;
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177 return block;
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178 }
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179
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180 //---------------------------- IndexSet::free_block() -------------------------
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181 // Add a BitBlock to the free list.
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182
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183 void IndexSet::free_block(uint i) {
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184 debug_only(check_watch("free block", i));
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185 assert(i < _max_blocks, "block index too large");
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186 BitBlock *block = _blocks[i];
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187 assert(block != &_empty_block, "cannot free the empty block");
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188 block->set_next((IndexSet::BitBlock*)Compile::current()->indexSet_free_block_list());
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189 Compile::current()->set_indexSet_free_block_list(block);
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190 set_block(i,&_empty_block);
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191 }
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192
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193 //------------------------------lrg_union--------------------------------------
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194 // Compute the union of all elements of one and two which interfere with
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195 // the RegMask mask. If the degree of the union becomes exceeds
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196 // fail_degree, the union bails out. The underlying set is cleared before
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197 // the union is performed.
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198
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199 uint IndexSet::lrg_union(uint lr1, uint lr2,
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200 const uint fail_degree,
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201 const PhaseIFG *ifg,
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202 const RegMask &mask ) {
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203 IndexSet *one = ifg->neighbors(lr1);
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204 IndexSet *two = ifg->neighbors(lr2);
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205 LRG &lrg1 = ifg->lrgs(lr1);
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206 LRG &lrg2 = ifg->lrgs(lr2);
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207 #ifdef ASSERT
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208 assert(_max_elements == one->_max_elements, "max element mismatch");
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209 check_watch("union destination");
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210 one->check_watch("union source");
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211 two->check_watch("union source");
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212 #endif
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213
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214 // Compute the degree of the combined live-range. The combined
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215 // live-range has the union of the original live-ranges' neighbors set as
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216 // well as the neighbors of all intermediate copies, minus those neighbors
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217 // that can not use the intersected allowed-register-set.
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218
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219 // Copy the larger set. Insert the smaller set into the larger.
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220 if (two->count() > one->count()) {
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221 IndexSet *temp = one;
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222 one = two;
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223 two = temp;
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224 }
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225
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226 clear();
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227
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228 // Used to compute degree of register-only interferences. Infinite-stack
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229 // neighbors do not alter colorability, as they can always color to some
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230 // other color. (A variant of the Briggs assertion)
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231 uint reg_degree = 0;
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232
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233 uint element;
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234 // Load up the combined interference set with the neighbors of one
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235 IndexSetIterator elements(one);
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236 while ((element = elements.next()) != 0) {
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237 LRG &lrg = ifg->lrgs(element);
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238 if (mask.overlap(lrg.mask())) {
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239 insert(element);
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240 if( !lrg.mask().is_AllStack() ) {
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241 reg_degree += lrg1.compute_degree(lrg);
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242 if( reg_degree >= fail_degree ) return reg_degree;
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243 } else {
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244 // !!!!! Danger! No update to reg_degree despite having a neighbor.
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245 // A variant of the Briggs assertion.
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246 // Not needed if I simplify during coalesce, ala George/Appel.
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247 assert( lrg.lo_degree(), "" );
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248 }
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249 }
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250 }
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251 // Add neighbors of two as well
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252 IndexSetIterator elements2(two);
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253 while ((element = elements2.next()) != 0) {
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254 LRG &lrg = ifg->lrgs(element);
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255 if (mask.overlap(lrg.mask())) {
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256 if (insert(element)) {
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257 if( !lrg.mask().is_AllStack() ) {
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258 reg_degree += lrg2.compute_degree(lrg);
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259 if( reg_degree >= fail_degree ) return reg_degree;
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260 } else {
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261 // !!!!! Danger! No update to reg_degree despite having a neighbor.
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262 // A variant of the Briggs assertion.
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263 // Not needed if I simplify during coalesce, ala George/Appel.
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264 assert( lrg.lo_degree(), "" );
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265 }
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266 }
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267 }
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268 }
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269
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270 return reg_degree;
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271 }
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272
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273 //---------------------------- IndexSet() -----------------------------
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274 // A deep copy constructor. This is used when you need a scratch copy of this set.
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275
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276 IndexSet::IndexSet (IndexSet *set) {
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277 #ifdef ASSERT
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278 _serial_number = _serial_count++;
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279 set->check_watch("copied", _serial_number);
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280 check_watch("initialized by copy", set->_serial_number);
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281 _max_elements = set->_max_elements;
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282 #endif
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283 _count = set->_count;
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284 _max_blocks = set->_max_blocks;
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285 if (_max_blocks <= preallocated_block_list_size) {
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286 _blocks = _preallocated_block_list;
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287 } else {
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288 _blocks =
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289 (IndexSet::BitBlock**) arena()->Amalloc_4(sizeof(IndexSet::BitBlock**) * _max_blocks);
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290 }
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291 for (uint i = 0; i < _max_blocks; i++) {
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292 BitBlock *block = set->_blocks[i];
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293 if (block == &_empty_block) {
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294 set_block(i, &_empty_block);
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295 } else {
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296 BitBlock *new_block = alloc_block();
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297 memcpy(new_block->words(), block->words(), sizeof(uint32) * words_per_block);
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298 set_block(i, new_block);
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299 }
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300 }
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301 }
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302
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303 //---------------------------- IndexSet::initialize() -----------------------------
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304 // Prepare an IndexSet for use.
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305
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306 void IndexSet::initialize(uint max_elements) {
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307 #ifdef ASSERT
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308 _serial_number = _serial_count++;
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309 check_watch("initialized", max_elements);
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310 _max_elements = max_elements;
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311 #endif
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312 _count = 0;
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313 _max_blocks = (max_elements + bits_per_block - 1) / bits_per_block;
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314
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315 if (_max_blocks <= preallocated_block_list_size) {
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316 _blocks = _preallocated_block_list;
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317 } else {
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318 _blocks = (IndexSet::BitBlock**) arena()->Amalloc_4(sizeof(IndexSet::BitBlock**) * _max_blocks);
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319 }
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320 for (uint i = 0; i < _max_blocks; i++) {
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321 set_block(i, &_empty_block);
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322 }
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323 }
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324
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325 //---------------------------- IndexSet::initialize()------------------------------
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326 // Prepare an IndexSet for use. If it needs to allocate its _blocks array, it does
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327 // so from the Arena passed as a parameter. BitBlock allocation is still done from
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328 // the static Arena which was set with reset_memory().
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329
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330 void IndexSet::initialize(uint max_elements, Arena *arena) {
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331 #ifdef ASSERT
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332 _serial_number = _serial_count++;
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333 check_watch("initialized2", max_elements);
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334 _max_elements = max_elements;
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335 #endif // ASSERT
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336 _count = 0;
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337 _max_blocks = (max_elements + bits_per_block - 1) / bits_per_block;
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338
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339 if (_max_blocks <= preallocated_block_list_size) {
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340 _blocks = _preallocated_block_list;
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341 } else {
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342 _blocks = (IndexSet::BitBlock**) arena->Amalloc_4(sizeof(IndexSet::BitBlock**) * _max_blocks);
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343 }
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344 for (uint i = 0; i < _max_blocks; i++) {
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345 set_block(i, &_empty_block);
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346 }
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347 }
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348
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349 //---------------------------- IndexSet::swap() -----------------------------
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350 // Exchange two IndexSets.
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351
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352 void IndexSet::swap(IndexSet *set) {
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353 #ifdef ASSERT
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354 assert(_max_elements == set->_max_elements, "must have same universe size to swap");
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355 check_watch("swap", set->_serial_number);
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356 set->check_watch("swap", _serial_number);
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357 #endif
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358
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359 for (uint i = 0; i < _max_blocks; i++) {
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360 BitBlock *temp = _blocks[i];
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361 set_block(i, set->_blocks[i]);
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362 set->set_block(i, temp);
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363 }
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364 uint temp = _count;
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365 _count = set->_count;
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366 set->_count = temp;
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367 }
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368
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369 //---------------------------- IndexSet::dump() -----------------------------
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370 // Print this set. Used for debugging.
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371
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372 #ifndef PRODUCT
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373 void IndexSet::dump() const {
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374 IndexSetIterator elements(this);
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375
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376 tty->print("{");
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377 uint i;
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378 while ((i = elements.next()) != 0) {
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379 tty->print("L%d ", i);
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380 }
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381 tty->print_cr("}");
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382 }
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383 #endif
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384
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385 #ifdef ASSERT
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386 //---------------------------- IndexSet::tally_iteration_statistics() -----------------------------
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387 // Update block/bit counts to reflect that this set has been iterated over.
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388
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389 void IndexSet::tally_iteration_statistics() const {
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390 _total_bits += count();
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391
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392 for (uint i = 0; i < _max_blocks; i++) {
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393 if (_blocks[i] != &_empty_block) {
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394 _total_used_blocks++;
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395 } else {
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396 _total_unused_blocks++;
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397 }
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398 }
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399 }
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400
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401 //---------------------------- IndexSet::print_statistics() -----------------------------
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402 // Print statistics about IndexSet usage.
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403
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404 void IndexSet::print_statistics() {
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405 long total_blocks = _total_used_blocks + _total_unused_blocks;
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406 tty->print_cr ("Accumulated IndexSet usage statistics:");
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407 tty->print_cr ("--------------------------------------");
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408 tty->print_cr (" Iteration:");
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409 tty->print_cr (" blocks visited: %d", total_blocks);
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410 tty->print_cr (" blocks empty: %4.2f%%", 100.0*_total_unused_blocks/total_blocks);
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411 tty->print_cr (" bit density (bits/used blocks): %4.2f%%", (double)_total_bits/_total_used_blocks);
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412 tty->print_cr (" bit density (bits/all blocks): %4.2f%%", (double)_total_bits/total_blocks);
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413 tty->print_cr (" Allocation:");
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414 tty->print_cr (" blocks allocated: %d", _alloc_new);
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415 tty->print_cr (" blocks used/reused: %d", _alloc_total);
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416 }
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417
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418 //---------------------------- IndexSet::verify() -----------------------------
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419 // Expensive test of IndexSet sanity. Ensure that the count agrees with the
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420 // number of bits in the blocks. Make sure the iterator is seeing all elements
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421 // of the set. Meant for use during development.
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422
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423 void IndexSet::verify() const {
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424 assert(!member(0), "zero cannot be a member");
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425 uint count = 0;
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426 uint i;
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427 for (i = 1; i < _max_elements; i++) {
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428 if (member(i)) {
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429 count++;
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430 assert(count <= _count, "_count is messed up");
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431 }
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432 }
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433
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434 IndexSetIterator elements(this);
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435 count = 0;
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436 while ((i = elements.next()) != 0) {
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437 count++;
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438 assert(member(i), "returned a non member");
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439 assert(count <= _count, "iterator returned wrong number of elements");
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440 }
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441 }
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442 #endif
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443
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444 //---------------------------- IndexSetIterator() -----------------------------
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445 // Create an iterator for a set. If empty blocks are detected when iterating
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446 // over the set, these blocks are replaced.
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447
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448 IndexSetIterator::IndexSetIterator(IndexSet *set) {
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449 #ifdef ASSERT
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450 if (CollectIndexSetStatistics) {
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451 set->tally_iteration_statistics();
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452 }
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453 set->check_watch("traversed", set->count());
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454 #endif
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455 if (set->is_empty()) {
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456 _current = 0;
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457 _next_word = IndexSet::words_per_block;
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458 _next_block = 1;
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459 _max_blocks = 1;
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460
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461 // We don't need the following values when we iterate over an empty set.
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462 // The commented out code is left here to document that the omission
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463 // is intentional.
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464 //
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465 //_value = 0;
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466 //_words = NULL;
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467 //_blocks = NULL;
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468 //_set = NULL;
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469 } else {
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470 _current = 0;
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471 _value = 0;
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472 _next_block = 0;
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473 _next_word = IndexSet::words_per_block;
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474
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475 _max_blocks = set->_max_blocks;
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476 _words = NULL;
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477 _blocks = set->_blocks;
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478 _set = set;
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479 }
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480 }
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481
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482 //---------------------------- IndexSetIterator(const) -----------------------------
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483 // Iterate over a constant IndexSet.
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484
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485 IndexSetIterator::IndexSetIterator(const IndexSet *set) {
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486 #ifdef ASSERT
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487 if (CollectIndexSetStatistics) {
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488 set->tally_iteration_statistics();
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489 }
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490 // We don't call check_watch from here to avoid bad recursion.
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491 // set->check_watch("traversed const", set->count());
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492 #endif
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493 if (set->is_empty()) {
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494 _current = 0;
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495 _next_word = IndexSet::words_per_block;
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496 _next_block = 1;
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497 _max_blocks = 1;
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498
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499 // We don't need the following values when we iterate over an empty set.
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500 // The commented out code is left here to document that the omission
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501 // is intentional.
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502 //
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503 //_value = 0;
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504 //_words = NULL;
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505 //_blocks = NULL;
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506 //_set = NULL;
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507 } else {
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508 _current = 0;
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509 _value = 0;
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510 _next_block = 0;
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511 _next_word = IndexSet::words_per_block;
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512
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513 _max_blocks = set->_max_blocks;
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514 _words = NULL;
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515 _blocks = set->_blocks;
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516 _set = NULL;
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517 }
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518 }
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519
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520 //---------------------------- List16Iterator::advance_and_next() -----------------------------
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521 // Advance to the next non-empty word in the set being iterated over. Return the next element
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522 // if there is one. If we are done, return 0. This method is called from the next() method
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523 // when it gets done with a word.
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524
|
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525 uint IndexSetIterator::advance_and_next() {
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526 // See if there is another non-empty word in the current block.
|
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527 for (uint wi = _next_word; wi < (unsigned)IndexSet::words_per_block; wi++) {
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528 if (_words[wi] != 0) {
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529 // Found a non-empty word.
|
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530 _value = ((_next_block - 1) * IndexSet::bits_per_block) + (wi * IndexSet::bits_per_word);
|
|
531 _current = _words[wi];
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532
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533 _next_word = wi+1;
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534
|
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535 return next();
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536 }
|
|
537 }
|
|
538
|
|
539 // We ran out of words in the current block. Advance to next non-empty block.
|
|
540 for (uint bi = _next_block; bi < _max_blocks; bi++) {
|
|
541 if (_blocks[bi] != &IndexSet::_empty_block) {
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542 // Found a non-empty block.
|
|
543
|
|
544 _words = _blocks[bi]->words();
|
|
545 for (uint wi = 0; wi < (unsigned)IndexSet::words_per_block; wi++) {
|
|
546 if (_words[wi] != 0) {
|
|
547 // Found a non-empty word.
|
|
548 _value = (bi * IndexSet::bits_per_block) + (wi * IndexSet::bits_per_word);
|
|
549 _current = _words[wi];
|
|
550
|
|
551 _next_block = bi+1;
|
|
552 _next_word = wi+1;
|
|
553
|
|
554 return next();
|
|
555 }
|
|
556 }
|
|
557
|
|
558 // All of the words in the block were empty. Replace
|
|
559 // the block with the empty block.
|
|
560 if (_set) {
|
|
561 _set->free_block(bi);
|
|
562 }
|
|
563 }
|
|
564 }
|
|
565
|
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566 // These assignments make redundant calls to next on a finished iterator
|
|
567 // faster. Probably not necessary.
|
|
568 _next_block = _max_blocks;
|
|
569 _next_word = IndexSet::words_per_block;
|
|
570
|
|
571 // No more words.
|
|
572 return 0;
|
|
573 }
|