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annotate src/share/vm/opto/indexSet.cpp @ 12355:cefad50507d8
Merge with hs25-b53
| author | Gilles Duboscq <duboscq@ssw.jku.at> |
|---|---|
| date | Fri, 11 Oct 2013 10:38:03 +0200 |
| parents | f7de3327c683 |
| children |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2250 | 2 * Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
|
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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. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "memory/allocation.inline.hpp" | |
| 27 #include "opto/chaitin.hpp" | |
| 28 #include "opto/compile.hpp" | |
| 29 #include "opto/indexSet.hpp" | |
| 30 #include "opto/regmask.hpp" | |
| 31 | |
| 0 | 32 // This file defines the IndexSet class, a set of sparse integer indices. |
| 33 // This data structure is used by the compiler in its liveness analysis and | |
| 34 // during register allocation. It also defines an iterator for this class. | |
| 35 | |
| 36 //-------------------------------- Initializations ------------------------------ | |
| 37 | |
| 38 IndexSet::BitBlock IndexSet::_empty_block = IndexSet::BitBlock(); | |
| 39 | |
| 40 #ifdef ASSERT | |
| 41 // Initialize statistics counters | |
| 2250 | 42 julong IndexSet::_alloc_new = 0; |
| 43 julong IndexSet::_alloc_total = 0; | |
| 0 | 44 |
| 2250 | 45 julong IndexSet::_total_bits = 0; |
| 46 julong IndexSet::_total_used_blocks = 0; | |
| 47 julong IndexSet::_total_unused_blocks = 0; | |
| 0 | 48 |
| 49 // Per set, or all sets operation tracing | |
| 50 int IndexSet::_serial_count = 1; | |
| 51 #endif | |
| 52 | |
| 53 // What is the first set bit in a 5 bit integer? | |
| 54 const byte IndexSetIterator::_first_bit[32] = { | |
| 55 0, 0, 1, 0, | |
| 56 2, 0, 1, 0, | |
| 57 3, 0, 1, 0, | |
| 58 2, 0, 1, 0, | |
| 59 4, 0, 1, 0, | |
| 60 2, 0, 1, 0, | |
| 61 3, 0, 1, 0, | |
| 62 2, 0, 1, 0 | |
| 63 }; | |
| 64 | |
| 65 // What is the second set bit in a 5 bit integer? | |
| 66 const byte IndexSetIterator::_second_bit[32] = { | |
| 67 5, 5, 5, 1, | |
| 68 5, 2, 2, 1, | |
| 69 5, 3, 3, 1, | |
| 70 3, 2, 2, 1, | |
| 71 5, 4, 4, 1, | |
| 72 4, 2, 2, 1, | |
| 73 4, 3, 3, 1, | |
| 74 3, 2, 2, 1 | |
| 75 }; | |
| 76 | |
| 77 // I tried implementing the IndexSetIterator with a window_size of 8 and | |
| 78 // didn't seem to get a noticeable speedup. I am leaving in the tables | |
| 79 // in case we want to switch back. | |
| 80 | |
| 81 /*const byte IndexSetIterator::_first_bit[256] = { | |
| 82 8, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 83 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 84 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 85 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 86 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 87 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 88 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 89 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 90 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 91 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 92 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 93 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 94 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 95 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 96 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, | |
| 97 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 | |
| 98 }; | |
| 99 | |
| 100 const byte IndexSetIterator::_second_bit[256] = { | |
| 101 8, 8, 8, 1, 8, 2, 2, 1, 8, 3, 3, 1, 3, 2, 2, 1, | |
| 102 8, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1, | |
| 103 8, 5, 5, 1, 5, 2, 2, 1, 5, 3, 3, 1, 3, 2, 2, 1, | |
| 104 5, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1, | |
| 105 8, 6, 6, 1, 6, 2, 2, 1, 6, 3, 3, 1, 3, 2, 2, 1, | |
| 106 6, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1, | |
| 107 6, 5, 5, 1, 5, 2, 2, 1, 5, 3, 3, 1, 3, 2, 2, 1, | |
| 108 5, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1, | |
| 109 8, 7, 7, 1, 7, 2, 2, 1, 7, 3, 3, 1, 3, 2, 2, 1, | |
| 110 7, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1, | |
| 111 7, 5, 5, 1, 5, 2, 2, 1, 5, 3, 3, 1, 3, 2, 2, 1, | |
| 112 5, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1, | |
| 113 7, 6, 6, 1, 6, 2, 2, 1, 6, 3, 3, 1, 3, 2, 2, 1, | |
| 114 6, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1, | |
| 115 6, 5, 5, 1, 5, 2, 2, 1, 5, 3, 3, 1, 3, 2, 2, 1, | |
| 116 5, 4, 4, 1, 4, 2, 2, 1, 4, 3, 3, 1, 3, 2, 2, 1 | |
| 117 };*/ | |
| 118 | |
| 119 //---------------------------- IndexSet::populate_free_list() ----------------------------- | |
| 120 // Populate the free BitBlock list with a batch of BitBlocks. The BitBlocks | |
| 121 // are 32 bit aligned. | |
| 122 | |
| 123 void IndexSet::populate_free_list() { | |
| 124 Compile *compile = Compile::current(); | |
| 125 BitBlock *free = (BitBlock*)compile->indexSet_free_block_list(); | |
| 126 | |
| 127 char *mem = (char*)arena()->Amalloc_4(sizeof(BitBlock) * | |
| 128 bitblock_alloc_chunk_size + 32); | |
| 129 | |
| 130 // Align the pointer to a 32 bit boundary. | |
| 131 BitBlock *new_blocks = (BitBlock*)(((uintptr_t)mem + 32) & ~0x001F); | |
| 132 | |
| 133 // Add the new blocks to the free list. | |
| 134 for (int i = 0; i < bitblock_alloc_chunk_size; i++) { | |
| 135 new_blocks->set_next(free); | |
| 136 free = new_blocks; | |
| 137 new_blocks++; | |
| 138 } | |
| 139 | |
| 140 compile->set_indexSet_free_block_list(free); | |
| 141 | |
| 142 #ifdef ASSERT | |
| 143 if (CollectIndexSetStatistics) { | |
| 2250 | 144 inc_stat_counter(&_alloc_new, bitblock_alloc_chunk_size); |
| 0 | 145 } |
| 146 #endif | |
| 147 } | |
| 148 | |
| 149 | |
| 150 //---------------------------- IndexSet::alloc_block() ------------------------ | |
| 151 // Allocate a BitBlock from the free list. If the free list is empty, | |
| 152 // prime it. | |
| 153 | |
| 154 IndexSet::BitBlock *IndexSet::alloc_block() { | |
| 155 #ifdef ASSERT | |
| 156 if (CollectIndexSetStatistics) { | |
| 2250 | 157 inc_stat_counter(&_alloc_total, 1); |
| 0 | 158 } |
| 159 #endif | |
| 160 Compile *compile = Compile::current(); | |
| 161 BitBlock* free_list = (BitBlock*)compile->indexSet_free_block_list(); | |
| 162 if (free_list == NULL) { | |
| 163 populate_free_list(); | |
| 164 free_list = (BitBlock*)compile->indexSet_free_block_list(); | |
| 165 } | |
| 166 BitBlock *block = free_list; | |
| 167 compile->set_indexSet_free_block_list(block->next()); | |
| 168 | |
| 169 block->clear(); | |
| 170 return block; | |
| 171 } | |
| 172 | |
| 173 //---------------------------- IndexSet::alloc_block_containing() ------------- | |
| 174 // Allocate a new BitBlock and put it into the position in the _blocks array | |
| 175 // corresponding to element. | |
| 176 | |
| 177 IndexSet::BitBlock *IndexSet::alloc_block_containing(uint element) { | |
| 178 BitBlock *block = alloc_block(); | |
| 179 uint bi = get_block_index(element); | |
| 180 _blocks[bi] = block; | |
| 181 return block; | |
| 182 } | |
| 183 | |
| 184 //---------------------------- IndexSet::free_block() ------------------------- | |
| 185 // Add a BitBlock to the free list. | |
| 186 | |
| 187 void IndexSet::free_block(uint i) { | |
| 188 debug_only(check_watch("free block", i)); | |
| 189 assert(i < _max_blocks, "block index too large"); | |
| 190 BitBlock *block = _blocks[i]; | |
| 191 assert(block != &_empty_block, "cannot free the empty block"); | |
| 192 block->set_next((IndexSet::BitBlock*)Compile::current()->indexSet_free_block_list()); | |
| 193 Compile::current()->set_indexSet_free_block_list(block); | |
| 194 set_block(i,&_empty_block); | |
| 195 } | |
| 196 | |
| 197 //------------------------------lrg_union-------------------------------------- | |
| 198 // Compute the union of all elements of one and two which interfere with | |
| 199 // the RegMask mask. If the degree of the union becomes exceeds | |
| 200 // fail_degree, the union bails out. The underlying set is cleared before | |
| 201 // the union is performed. | |
| 202 | |
| 203 uint IndexSet::lrg_union(uint lr1, uint lr2, | |
| 204 const uint fail_degree, | |
| 205 const PhaseIFG *ifg, | |
| 206 const RegMask &mask ) { | |
| 207 IndexSet *one = ifg->neighbors(lr1); | |
| 208 IndexSet *two = ifg->neighbors(lr2); | |
| 209 LRG &lrg1 = ifg->lrgs(lr1); | |
| 210 LRG &lrg2 = ifg->lrgs(lr2); | |
| 211 #ifdef ASSERT | |
| 212 assert(_max_elements == one->_max_elements, "max element mismatch"); | |
| 213 check_watch("union destination"); | |
| 214 one->check_watch("union source"); | |
| 215 two->check_watch("union source"); | |
| 216 #endif | |
| 217 | |
| 218 // Compute the degree of the combined live-range. The combined | |
| 219 // live-range has the union of the original live-ranges' neighbors set as | |
| 220 // well as the neighbors of all intermediate copies, minus those neighbors | |
| 221 // that can not use the intersected allowed-register-set. | |
| 222 | |
| 223 // Copy the larger set. Insert the smaller set into the larger. | |
| 224 if (two->count() > one->count()) { | |
| 225 IndexSet *temp = one; | |
| 226 one = two; | |
| 227 two = temp; | |
| 228 } | |
| 229 | |
| 230 clear(); | |
| 231 | |
| 232 // Used to compute degree of register-only interferences. Infinite-stack | |
| 233 // neighbors do not alter colorability, as they can always color to some | |
| 234 // other color. (A variant of the Briggs assertion) | |
| 235 uint reg_degree = 0; | |
| 236 | |
| 237 uint element; | |
| 238 // Load up the combined interference set with the neighbors of one | |
| 239 IndexSetIterator elements(one); | |
| 240 while ((element = elements.next()) != 0) { | |
| 241 LRG &lrg = ifg->lrgs(element); | |
| 242 if (mask.overlap(lrg.mask())) { | |
| 243 insert(element); | |
| 244 if( !lrg.mask().is_AllStack() ) { | |
| 245 reg_degree += lrg1.compute_degree(lrg); | |
| 246 if( reg_degree >= fail_degree ) return reg_degree; | |
| 247 } else { | |
| 248 // !!!!! Danger! No update to reg_degree despite having a neighbor. | |
| 249 // A variant of the Briggs assertion. | |
| 250 // Not needed if I simplify during coalesce, ala George/Appel. | |
| 251 assert( lrg.lo_degree(), "" ); | |
| 252 } | |
| 253 } | |
| 254 } | |
| 255 // Add neighbors of two as well | |
| 256 IndexSetIterator elements2(two); | |
| 257 while ((element = elements2.next()) != 0) { | |
| 258 LRG &lrg = ifg->lrgs(element); | |
| 259 if (mask.overlap(lrg.mask())) { | |
| 260 if (insert(element)) { | |
| 261 if( !lrg.mask().is_AllStack() ) { | |
| 262 reg_degree += lrg2.compute_degree(lrg); | |
| 263 if( reg_degree >= fail_degree ) return reg_degree; | |
| 264 } else { | |
| 265 // !!!!! Danger! No update to reg_degree despite having a neighbor. | |
| 266 // A variant of the Briggs assertion. | |
| 267 // Not needed if I simplify during coalesce, ala George/Appel. | |
| 268 assert( lrg.lo_degree(), "" ); | |
| 269 } | |
| 270 } | |
| 271 } | |
| 272 } | |
| 273 | |
| 274 return reg_degree; | |
| 275 } | |
| 276 | |
| 277 //---------------------------- IndexSet() ----------------------------- | |
| 278 // A deep copy constructor. This is used when you need a scratch copy of this set. | |
| 279 | |
| 280 IndexSet::IndexSet (IndexSet *set) { | |
| 281 #ifdef ASSERT | |
| 282 _serial_number = _serial_count++; | |
| 283 set->check_watch("copied", _serial_number); | |
| 284 check_watch("initialized by copy", set->_serial_number); | |
| 285 _max_elements = set->_max_elements; | |
| 286 #endif | |
| 287 _count = set->_count; | |
| 288 _max_blocks = set->_max_blocks; | |
| 289 if (_max_blocks <= preallocated_block_list_size) { | |
| 290 _blocks = _preallocated_block_list; | |
| 291 } else { | |
| 292 _blocks = | |
| 293 (IndexSet::BitBlock**) arena()->Amalloc_4(sizeof(IndexSet::BitBlock**) * _max_blocks); | |
| 294 } | |
| 295 for (uint i = 0; i < _max_blocks; i++) { | |
| 296 BitBlock *block = set->_blocks[i]; | |
| 297 if (block == &_empty_block) { | |
| 298 set_block(i, &_empty_block); | |
| 299 } else { | |
| 300 BitBlock *new_block = alloc_block(); | |
| 301 memcpy(new_block->words(), block->words(), sizeof(uint32) * words_per_block); | |
| 302 set_block(i, new_block); | |
| 303 } | |
| 304 } | |
| 305 } | |
| 306 | |
| 307 //---------------------------- IndexSet::initialize() ----------------------------- | |
| 308 // Prepare an IndexSet for use. | |
| 309 | |
| 310 void IndexSet::initialize(uint max_elements) { | |
| 311 #ifdef ASSERT | |
| 312 _serial_number = _serial_count++; | |
| 313 check_watch("initialized", max_elements); | |
| 314 _max_elements = max_elements; | |
| 315 #endif | |
| 316 _count = 0; | |
| 317 _max_blocks = (max_elements + bits_per_block - 1) / bits_per_block; | |
| 318 | |
| 319 if (_max_blocks <= preallocated_block_list_size) { | |
| 320 _blocks = _preallocated_block_list; | |
| 321 } else { | |
| 322 _blocks = (IndexSet::BitBlock**) arena()->Amalloc_4(sizeof(IndexSet::BitBlock**) * _max_blocks); | |
| 323 } | |
| 324 for (uint i = 0; i < _max_blocks; i++) { | |
| 325 set_block(i, &_empty_block); | |
| 326 } | |
| 327 } | |
| 328 | |
| 329 //---------------------------- IndexSet::initialize()------------------------------ | |
| 330 // Prepare an IndexSet for use. If it needs to allocate its _blocks array, it does | |
| 331 // so from the Arena passed as a parameter. BitBlock allocation is still done from | |
| 332 // the static Arena which was set with reset_memory(). | |
| 333 | |
| 334 void IndexSet::initialize(uint max_elements, Arena *arena) { | |
| 335 #ifdef ASSERT | |
| 336 _serial_number = _serial_count++; | |
| 337 check_watch("initialized2", max_elements); | |
| 338 _max_elements = max_elements; | |
| 339 #endif // ASSERT | |
| 340 _count = 0; | |
| 341 _max_blocks = (max_elements + bits_per_block - 1) / bits_per_block; | |
| 342 | |
| 343 if (_max_blocks <= preallocated_block_list_size) { | |
| 344 _blocks = _preallocated_block_list; | |
| 345 } else { | |
| 346 _blocks = (IndexSet::BitBlock**) arena->Amalloc_4(sizeof(IndexSet::BitBlock**) * _max_blocks); | |
| 347 } | |
| 348 for (uint i = 0; i < _max_blocks; i++) { | |
| 349 set_block(i, &_empty_block); | |
| 350 } | |
| 351 } | |
| 352 | |
| 353 //---------------------------- IndexSet::swap() ----------------------------- | |
| 354 // Exchange two IndexSets. | |
| 355 | |
| 356 void IndexSet::swap(IndexSet *set) { | |
| 357 #ifdef ASSERT | |
| 358 assert(_max_elements == set->_max_elements, "must have same universe size to swap"); | |
| 359 check_watch("swap", set->_serial_number); | |
| 360 set->check_watch("swap", _serial_number); | |
| 361 #endif | |
| 362 | |
| 363 for (uint i = 0; i < _max_blocks; i++) { | |
| 364 BitBlock *temp = _blocks[i]; | |
| 365 set_block(i, set->_blocks[i]); | |
| 366 set->set_block(i, temp); | |
| 367 } | |
| 368 uint temp = _count; | |
| 369 _count = set->_count; | |
| 370 set->_count = temp; | |
| 371 } | |
| 372 | |
| 373 //---------------------------- IndexSet::dump() ----------------------------- | |
| 374 // Print this set. Used for debugging. | |
| 375 | |
| 376 #ifndef PRODUCT | |
| 377 void IndexSet::dump() const { | |
| 378 IndexSetIterator elements(this); | |
| 379 | |
| 380 tty->print("{"); | |
| 381 uint i; | |
| 382 while ((i = elements.next()) != 0) { | |
| 383 tty->print("L%d ", i); | |
| 384 } | |
| 385 tty->print_cr("}"); | |
| 386 } | |
| 387 #endif | |
| 388 | |
| 389 #ifdef ASSERT | |
| 390 //---------------------------- IndexSet::tally_iteration_statistics() ----------------------------- | |
| 391 // Update block/bit counts to reflect that this set has been iterated over. | |
| 392 | |
| 393 void IndexSet::tally_iteration_statistics() const { | |
| 2250 | 394 inc_stat_counter(&_total_bits, count()); |
| 0 | 395 |
| 396 for (uint i = 0; i < _max_blocks; i++) { | |
| 397 if (_blocks[i] != &_empty_block) { | |
| 2250 | 398 inc_stat_counter(&_total_used_blocks, 1); |
| 0 | 399 } else { |
| 2250 | 400 inc_stat_counter(&_total_unused_blocks, 1); |
| 0 | 401 } |
| 402 } | |
| 403 } | |
| 404 | |
| 405 //---------------------------- IndexSet::print_statistics() ----------------------------- | |
| 406 // Print statistics about IndexSet usage. | |
| 407 | |
| 408 void IndexSet::print_statistics() { | |
| 2250 | 409 julong total_blocks = _total_used_blocks + _total_unused_blocks; |
| 0 | 410 tty->print_cr ("Accumulated IndexSet usage statistics:"); |
| 411 tty->print_cr ("--------------------------------------"); | |
| 412 tty->print_cr (" Iteration:"); | |
| 2250 | 413 tty->print_cr (" blocks visited: " UINT64_FORMAT, total_blocks); |
| 414 tty->print_cr (" blocks empty: %4.2f%%", 100.0*(double)_total_unused_blocks/total_blocks); | |
| 415 tty->print_cr (" bit density (bits/used blocks): %4.2f", (double)_total_bits/_total_used_blocks); | |
| 416 tty->print_cr (" bit density (bits/all blocks): %4.2f", (double)_total_bits/total_blocks); | |
| 0 | 417 tty->print_cr (" Allocation:"); |
| 2250 | 418 tty->print_cr (" blocks allocated: " UINT64_FORMAT, _alloc_new); |
| 419 tty->print_cr (" blocks used/reused: " UINT64_FORMAT, _alloc_total); | |
| 0 | 420 } |
| 421 | |
| 422 //---------------------------- IndexSet::verify() ----------------------------- | |
| 423 // Expensive test of IndexSet sanity. Ensure that the count agrees with the | |
| 424 // number of bits in the blocks. Make sure the iterator is seeing all elements | |
| 425 // of the set. Meant for use during development. | |
| 426 | |
| 427 void IndexSet::verify() const { | |
| 428 assert(!member(0), "zero cannot be a member"); | |
| 429 uint count = 0; | |
| 430 uint i; | |
| 431 for (i = 1; i < _max_elements; i++) { | |
| 432 if (member(i)) { | |
| 433 count++; | |
| 434 assert(count <= _count, "_count is messed up"); | |
| 435 } | |
| 436 } | |
| 437 | |
| 438 IndexSetIterator elements(this); | |
| 439 count = 0; | |
| 440 while ((i = elements.next()) != 0) { | |
| 441 count++; | |
| 442 assert(member(i), "returned a non member"); | |
| 443 assert(count <= _count, "iterator returned wrong number of elements"); | |
| 444 } | |
| 445 } | |
| 446 #endif | |
| 447 | |
| 448 //---------------------------- IndexSetIterator() ----------------------------- | |
| 449 // Create an iterator for a set. If empty blocks are detected when iterating | |
| 450 // over the set, these blocks are replaced. | |
| 451 | |
| 452 IndexSetIterator::IndexSetIterator(IndexSet *set) { | |
| 453 #ifdef ASSERT | |
| 454 if (CollectIndexSetStatistics) { | |
| 455 set->tally_iteration_statistics(); | |
| 456 } | |
| 457 set->check_watch("traversed", set->count()); | |
| 458 #endif | |
| 459 if (set->is_empty()) { | |
| 460 _current = 0; | |
| 461 _next_word = IndexSet::words_per_block; | |
| 462 _next_block = 1; | |
| 463 _max_blocks = 1; | |
| 464 | |
| 465 // We don't need the following values when we iterate over an empty set. | |
| 466 // The commented out code is left here to document that the omission | |
| 467 // is intentional. | |
| 468 // | |
| 469 //_value = 0; | |
| 470 //_words = NULL; | |
| 471 //_blocks = NULL; | |
| 472 //_set = NULL; | |
| 473 } else { | |
| 474 _current = 0; | |
| 475 _value = 0; | |
| 476 _next_block = 0; | |
| 477 _next_word = IndexSet::words_per_block; | |
| 478 | |
| 479 _max_blocks = set->_max_blocks; | |
| 480 _words = NULL; | |
| 481 _blocks = set->_blocks; | |
| 482 _set = set; | |
| 483 } | |
| 484 } | |
| 485 | |
| 486 //---------------------------- IndexSetIterator(const) ----------------------------- | |
| 487 // Iterate over a constant IndexSet. | |
| 488 | |
| 489 IndexSetIterator::IndexSetIterator(const IndexSet *set) { | |
| 490 #ifdef ASSERT | |
| 491 if (CollectIndexSetStatistics) { | |
| 492 set->tally_iteration_statistics(); | |
| 493 } | |
| 494 // We don't call check_watch from here to avoid bad recursion. | |
| 495 // set->check_watch("traversed const", set->count()); | |
| 496 #endif | |
| 497 if (set->is_empty()) { | |
| 498 _current = 0; | |
| 499 _next_word = IndexSet::words_per_block; | |
| 500 _next_block = 1; | |
| 501 _max_blocks = 1; | |
| 502 | |
| 503 // We don't need the following values when we iterate over an empty set. | |
| 504 // The commented out code is left here to document that the omission | |
| 505 // is intentional. | |
| 506 // | |
| 507 //_value = 0; | |
| 508 //_words = NULL; | |
| 509 //_blocks = NULL; | |
| 510 //_set = NULL; | |
| 511 } else { | |
| 512 _current = 0; | |
| 513 _value = 0; | |
| 514 _next_block = 0; | |
| 515 _next_word = IndexSet::words_per_block; | |
| 516 | |
| 517 _max_blocks = set->_max_blocks; | |
| 518 _words = NULL; | |
| 519 _blocks = set->_blocks; | |
| 520 _set = NULL; | |
| 521 } | |
| 522 } | |
| 523 | |
| 524 //---------------------------- List16Iterator::advance_and_next() ----------------------------- | |
| 525 // Advance to the next non-empty word in the set being iterated over. Return the next element | |
| 526 // if there is one. If we are done, return 0. This method is called from the next() method | |
| 527 // when it gets done with a word. | |
| 528 | |
| 529 uint IndexSetIterator::advance_and_next() { | |
| 530 // See if there is another non-empty word in the current block. | |
| 531 for (uint wi = _next_word; wi < (unsigned)IndexSet::words_per_block; wi++) { | |
| 532 if (_words[wi] != 0) { | |
| 533 // Found a non-empty word. | |
| 534 _value = ((_next_block - 1) * IndexSet::bits_per_block) + (wi * IndexSet::bits_per_word); | |
| 535 _current = _words[wi]; | |
| 536 | |
| 537 _next_word = wi+1; | |
| 538 | |
| 539 return next(); | |
| 540 } | |
| 541 } | |
| 542 | |
| 543 // We ran out of words in the current block. Advance to next non-empty block. | |
| 544 for (uint bi = _next_block; bi < _max_blocks; bi++) { | |
| 545 if (_blocks[bi] != &IndexSet::_empty_block) { | |
| 546 // Found a non-empty block. | |
| 547 | |
| 548 _words = _blocks[bi]->words(); | |
| 549 for (uint wi = 0; wi < (unsigned)IndexSet::words_per_block; wi++) { | |
| 550 if (_words[wi] != 0) { | |
| 551 // Found a non-empty word. | |
| 552 _value = (bi * IndexSet::bits_per_block) + (wi * IndexSet::bits_per_word); | |
| 553 _current = _words[wi]; | |
| 554 | |
| 555 _next_block = bi+1; | |
| 556 _next_word = wi+1; | |
| 557 | |
| 558 return next(); | |
| 559 } | |
| 560 } | |
| 561 | |
| 562 // All of the words in the block were empty. Replace | |
| 563 // the block with the empty block. | |
| 564 if (_set) { | |
| 565 _set->free_block(bi); | |
| 566 } | |
| 567 } | |
| 568 } | |
| 569 | |
| 570 // These assignments make redundant calls to next on a finished iterator | |
| 571 // faster. Probably not necessary. | |
| 572 _next_block = _max_blocks; | |
| 573 _next_word = IndexSet::words_per_block; | |
| 574 | |
| 575 // No more words. | |
| 576 return 0; | |
| 577 } |