1/* 2 * Copyright (c) 1998, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "precompiled.hpp" 26#include "ci/ciMethod.hpp" 27#include "ci/ciMethodBlocks.hpp" 28#include "ci/ciStreams.hpp" 29#include "compiler/methodLiveness.hpp" 30#include "interpreter/bytecode.hpp" 31#include "interpreter/bytecodes.hpp" 32#include "memory/allocation.inline.hpp" 33#include "memory/resourceArea.hpp" 34#include "runtime/timerTrace.hpp" 35#include "utilities/bitMap.inline.hpp" 36 37// The MethodLiveness class performs a simple liveness analysis on a method 38// in order to decide which locals are live (that is, will be used again) at 39// a particular bytecode index (bci). 40// 41// The algorithm goes: 42// 43// 1. Break the method into a set of basic blocks. For each basic block we 44// also keep track of its set of predecessors through normal control flow 45// and predecessors through exceptional control flow. 46// 47// 2. For each basic block, compute two sets, gen (the set of values used before 48// they are defined) and kill (the set of values defined before they are used) 49// in the basic block. A basic block "needs" the locals in its gen set to 50// perform its computation. A basic block "provides" values for the locals in 51// its kill set, allowing a need from a successor to be ignored. 52// 53// 3. Liveness information (the set of locals which are needed) is pushed backwards through 54// the program, from blocks to their predecessors. We compute and store liveness 55// information for the normal/exceptional exit paths for each basic block. When 56// this process reaches a fixed point, we are done. 57// 58// 4. When we are asked about the liveness at a particular bci with a basic block, we 59// compute gen/kill sets which represent execution from that bci to the exit of 60// its blocks. We then compose this range gen/kill information with the normal 61// and exceptional exit information for the block to produce liveness information 62// at that bci. 63// 64// The algorithm is approximate in many respects. Notably: 65// 66// 1. We do not do the analysis necessary to match jsr's with the appropriate ret. 67// Instead we make the conservative assumption that any ret can return to any 68// jsr return site. 69// 2. Instead of computing the effects of exceptions at every instruction, we 70// summarize the effects of all exceptional continuations from the block as 71// a single set (_exception_exit), losing some information but simplifying the 72// analysis. 73 74 75//-------------------------------------------------------------------------- 76// The BitCounter class is used for counting the number of bits set in 77// some BitMap. It is only used when collecting liveness statistics. 78 79#ifndef PRODUCT 80 81class BitCounter: public BitMapClosure { 82 private: 83 int _count; 84 public: 85 BitCounter() : _count(0) {} 86 87 // Callback when bit in map is set 88 virtual bool do_bit(size_t offset) { 89 _count++; 90 return true; 91 } 92 93 int count() { 94 return _count; 95 } 96}; 97 98 99//-------------------------------------------------------------------------- 100 101 102// Counts 103long MethodLiveness::_total_bytes = 0; 104int MethodLiveness::_total_methods = 0; 105 106long MethodLiveness::_total_blocks = 0; 107int MethodLiveness::_max_method_blocks = 0; 108 109long MethodLiveness::_total_edges = 0; 110int MethodLiveness::_max_block_edges = 0; 111 112long MethodLiveness::_total_exc_edges = 0; 113int MethodLiveness::_max_block_exc_edges = 0; 114 115long MethodLiveness::_total_method_locals = 0; 116int MethodLiveness::_max_method_locals = 0; 117 118long MethodLiveness::_total_locals_queried = 0; 119long MethodLiveness::_total_live_locals_queried = 0; 120 121long MethodLiveness::_total_visits = 0; 122 123#endif 124 125// Timers 126elapsedTimer MethodLiveness::_time_build_graph; 127elapsedTimer MethodLiveness::_time_gen_kill; 128elapsedTimer MethodLiveness::_time_flow; 129elapsedTimer MethodLiveness::_time_query; 130elapsedTimer MethodLiveness::_time_total; 131 132MethodLiveness::MethodLiveness(Arena* arena, ciMethod* method) 133#ifdef COMPILER1 134 : _bci_block_start(arena, method->code_size()) 135#endif 136{ 137 _arena = arena; 138 _method = method; 139 _bit_map_size_bits = method->max_locals(); 140} 141 142void MethodLiveness::compute_liveness() { 143#ifndef PRODUCT 144 if (TraceLivenessGen) { 145 tty->print_cr("################################################################"); 146 tty->print("# Computing liveness information for "); 147 method()->print_short_name(); 148 } 149 150 if (TimeLivenessAnalysis) _time_total.start(); 151#endif 152 153 { 154 TraceTime buildGraph(NULL, &_time_build_graph, TimeLivenessAnalysis); 155 init_basic_blocks(); 156 } 157 { 158 TraceTime genKill(NULL, &_time_gen_kill, TimeLivenessAnalysis); 159 init_gen_kill(); 160 } 161 { 162 TraceTime flow(NULL, &_time_flow, TimeLivenessAnalysis); 163 propagate_liveness(); 164 } 165 166#ifndef PRODUCT 167 if (TimeLivenessAnalysis) _time_total.stop(); 168 169 if (TimeLivenessAnalysis) { 170 // Collect statistics 171 _total_bytes += method()->code_size(); 172 _total_methods++; 173 174 int num_blocks = _block_count; 175 _total_blocks += num_blocks; 176 _max_method_blocks = MAX2(num_blocks,_max_method_blocks); 177 178 for (int i=0; i<num_blocks; i++) { 179 BasicBlock *block = _block_list[i]; 180 181 int numEdges = block->_normal_predecessors->length(); 182 int numExcEdges = block->_exception_predecessors->length(); 183 184 _total_edges += numEdges; 185 _total_exc_edges += numExcEdges; 186 _max_block_edges = MAX2(numEdges,_max_block_edges); 187 _max_block_exc_edges = MAX2(numExcEdges,_max_block_exc_edges); 188 } 189 190 int numLocals = _bit_map_size_bits; 191 _total_method_locals += numLocals; 192 _max_method_locals = MAX2(numLocals,_max_method_locals); 193 } 194#endif 195} 196 197 198void MethodLiveness::init_basic_blocks() { 199 bool bailout = false; 200 201 int method_len = method()->code_size(); 202 ciMethodBlocks *mblocks = method()->get_method_blocks(); 203 204 // Create an array to store the bci->BasicBlock mapping. 205 _block_map = new (arena()) GrowableArray<BasicBlock*>(arena(), method_len, method_len, NULL); 206 207 _block_count = mblocks->num_blocks(); 208 _block_list = (BasicBlock **) arena()->Amalloc(sizeof(BasicBlock *) * _block_count); 209 210 // Used for patching up jsr/ret control flow. 211 GrowableArray<BasicBlock*>* jsr_exit_list = new GrowableArray<BasicBlock*>(5); 212 GrowableArray<BasicBlock*>* ret_list = new GrowableArray<BasicBlock*>(5); 213 214 // generate our block list from ciMethodBlocks 215 for (int blk = 0; blk < _block_count; blk++) { 216 ciBlock *cib = mblocks->block(blk); 217 int start_bci = cib->start_bci(); 218 _block_list[blk] = new (arena()) BasicBlock(this, start_bci, cib->limit_bci()); 219 _block_map->at_put(start_bci, _block_list[blk]); 220#ifdef COMPILER1 221 // mark all bcis where a new basic block starts 222 _bci_block_start.set_bit(start_bci); 223#endif // COMPILER1 224 } 225 // fill in the predecessors of blocks 226 ciBytecodeStream bytes(method()); 227 228 for (int blk = 0; blk < _block_count; blk++) { 229 BasicBlock *current_block = _block_list[blk]; 230 int bci = mblocks->block(blk)->control_bci(); 231 232 if (bci == ciBlock::fall_through_bci) { 233 int limit = current_block->limit_bci(); 234 if (limit < method_len) { 235 BasicBlock *next = _block_map->at(limit); 236 assert( next != NULL, "must be a block immediately following this one."); 237 next->add_normal_predecessor(current_block); 238 } 239 continue; 240 } 241 bytes.reset_to_bci(bci); 242 Bytecodes::Code code = bytes.next(); 243 BasicBlock *dest; 244 245 // Now we need to interpret the instruction's effect 246 // on control flow. 247 assert (current_block != NULL, "we must have a current block"); 248 switch (code) { 249 case Bytecodes::_ifeq: 250 case Bytecodes::_ifne: 251 case Bytecodes::_iflt: 252 case Bytecodes::_ifge: 253 case Bytecodes::_ifgt: 254 case Bytecodes::_ifle: 255 case Bytecodes::_if_icmpeq: 256 case Bytecodes::_if_icmpne: 257 case Bytecodes::_if_icmplt: 258 case Bytecodes::_if_icmpge: 259 case Bytecodes::_if_icmpgt: 260 case Bytecodes::_if_icmple: 261 case Bytecodes::_if_acmpeq: 262 case Bytecodes::_if_acmpne: 263 case Bytecodes::_ifnull: 264 case Bytecodes::_ifnonnull: 265 // Two way branch. Set predecessors at each destination. 266 dest = _block_map->at(bytes.next_bci()); 267 assert(dest != NULL, "must be a block immediately following this one."); 268 dest->add_normal_predecessor(current_block); 269 270 dest = _block_map->at(bytes.get_dest()); 271 assert(dest != NULL, "branch desination must start a block."); 272 dest->add_normal_predecessor(current_block); 273 break; 274 case Bytecodes::_goto: 275 dest = _block_map->at(bytes.get_dest()); 276 assert(dest != NULL, "branch desination must start a block."); 277 dest->add_normal_predecessor(current_block); 278 break; 279 case Bytecodes::_goto_w: 280 dest = _block_map->at(bytes.get_far_dest()); 281 assert(dest != NULL, "branch desination must start a block."); 282 dest->add_normal_predecessor(current_block); 283 break; 284 case Bytecodes::_tableswitch: 285 { 286 Bytecode_tableswitch tableswitch(&bytes); 287 288 int len = tableswitch.length(); 289 290 dest = _block_map->at(bci + tableswitch.default_offset()); 291 assert(dest != NULL, "branch desination must start a block."); 292 dest->add_normal_predecessor(current_block); 293 while (--len >= 0) { 294 dest = _block_map->at(bci + tableswitch.dest_offset_at(len)); 295 assert(dest != NULL, "branch desination must start a block."); 296 dest->add_normal_predecessor(current_block); 297 } 298 break; 299 } 300 301 case Bytecodes::_lookupswitch: 302 { 303 Bytecode_lookupswitch lookupswitch(&bytes); 304 305 int npairs = lookupswitch.number_of_pairs(); 306 307 dest = _block_map->at(bci + lookupswitch.default_offset()); 308 assert(dest != NULL, "branch desination must start a block."); 309 dest->add_normal_predecessor(current_block); 310 while(--npairs >= 0) { 311 LookupswitchPair pair = lookupswitch.pair_at(npairs); 312 dest = _block_map->at( bci + pair.offset()); 313 assert(dest != NULL, "branch desination must start a block."); 314 dest->add_normal_predecessor(current_block); 315 } 316 break; 317 } 318 319 case Bytecodes::_jsr: 320 { 321 assert(bytes.is_wide()==false, "sanity check"); 322 dest = _block_map->at(bytes.get_dest()); 323 assert(dest != NULL, "branch desination must start a block."); 324 dest->add_normal_predecessor(current_block); 325 BasicBlock *jsrExit = _block_map->at(current_block->limit_bci()); 326 assert(jsrExit != NULL, "jsr return bci must start a block."); 327 jsr_exit_list->append(jsrExit); 328 break; 329 } 330 case Bytecodes::_jsr_w: 331 { 332 dest = _block_map->at(bytes.get_far_dest()); 333 assert(dest != NULL, "branch desination must start a block."); 334 dest->add_normal_predecessor(current_block); 335 BasicBlock *jsrExit = _block_map->at(current_block->limit_bci()); 336 assert(jsrExit != NULL, "jsr return bci must start a block."); 337 jsr_exit_list->append(jsrExit); 338 break; 339 } 340 341 case Bytecodes::_wide: 342 assert(false, "wide opcodes should not be seen here"); 343 break; 344 case Bytecodes::_athrow: 345 case Bytecodes::_ireturn: 346 case Bytecodes::_lreturn: 347 case Bytecodes::_freturn: 348 case Bytecodes::_dreturn: 349 case Bytecodes::_areturn: 350 case Bytecodes::_return: 351 // These opcodes are not the normal predecessors of any other opcodes. 352 break; 353 case Bytecodes::_ret: 354 // We will patch up jsr/rets in a subsequent pass. 355 ret_list->append(current_block); 356 break; 357 case Bytecodes::_breakpoint: 358 // Bail out of there are breakpoints in here. 359 bailout = true; 360 break; 361 default: 362 // Do nothing. 363 break; 364 } 365 } 366 // Patch up the jsr/ret's. We conservatively assume that any ret 367 // can return to any jsr site. 368 int ret_list_len = ret_list->length(); 369 int jsr_exit_list_len = jsr_exit_list->length(); 370 if (ret_list_len > 0 && jsr_exit_list_len > 0) { 371 for (int i = jsr_exit_list_len - 1; i >= 0; i--) { 372 BasicBlock *jsrExit = jsr_exit_list->at(i); 373 for (int i = ret_list_len - 1; i >= 0; i--) { 374 jsrExit->add_normal_predecessor(ret_list->at(i)); 375 } 376 } 377 } 378 379 // Compute exception edges. 380 for (int b=_block_count-1; b >= 0; b--) { 381 BasicBlock *block = _block_list[b]; 382 int block_start = block->start_bci(); 383 int block_limit = block->limit_bci(); 384 ciExceptionHandlerStream handlers(method()); 385 for (; !handlers.is_done(); handlers.next()) { 386 ciExceptionHandler* handler = handlers.handler(); 387 int start = handler->start(); 388 int limit = handler->limit(); 389 int handler_bci = handler->handler_bci(); 390 391 int intersect_start = MAX2(block_start, start); 392 int intersect_limit = MIN2(block_limit, limit); 393 if (intersect_start < intersect_limit) { 394 // The catch range has a nonempty intersection with this 395 // basic block. That means this basic block can be an 396 // exceptional predecessor. 397 _block_map->at(handler_bci)->add_exception_predecessor(block); 398 399 if (handler->is_catch_all()) { 400 // This is a catch-all block. 401 if (intersect_start == block_start && intersect_limit == block_limit) { 402 // The basic block is entirely contained in this catch-all block. 403 // Skip the rest of the exception handlers -- they can never be 404 // reached in execution. 405 break; 406 } 407 } 408 } 409 } 410 } 411} 412 413void MethodLiveness::init_gen_kill() { 414 for (int i=_block_count-1; i >= 0; i--) { 415 _block_list[i]->compute_gen_kill(method()); 416 } 417} 418 419void MethodLiveness::propagate_liveness() { 420 int num_blocks = _block_count; 421 BasicBlock *block; 422 423 // We start our work list off with all blocks in it. 424 // Alternately, we could start off the work list with the list of all 425 // blocks which could exit the method directly, along with one block 426 // from any infinite loop. If this matters, it can be changed. It 427 // may not be clear from looking at the code, but the order of the 428 // workList will be the opposite of the creation order of the basic 429 // blocks, which should be decent for quick convergence (with the 430 // possible exception of exception handlers, which are all created 431 // early). 432 _work_list = NULL; 433 for (int i = 0; i < num_blocks; i++) { 434 block = _block_list[i]; 435 block->set_next(_work_list); 436 block->set_on_work_list(true); 437 _work_list = block; 438 } 439 440 441 while ((block = work_list_get()) != NULL) { 442 block->propagate(this); 443 NOT_PRODUCT(_total_visits++;) 444 } 445} 446 447void MethodLiveness::work_list_add(BasicBlock *block) { 448 if (!block->on_work_list()) { 449 block->set_next(_work_list); 450 block->set_on_work_list(true); 451 _work_list = block; 452 } 453} 454 455MethodLiveness::BasicBlock *MethodLiveness::work_list_get() { 456 BasicBlock *block = _work_list; 457 if (block != NULL) { 458 block->set_on_work_list(false); 459 _work_list = block->next(); 460 } 461 return block; 462} 463 464 465MethodLivenessResult MethodLiveness::get_liveness_at(int entry_bci) { 466 int bci = entry_bci; 467 bool is_entry = false; 468 if (entry_bci == InvocationEntryBci) { 469 is_entry = true; 470 bci = 0; 471 } 472 473 MethodLivenessResult answer; 474 475 if (_block_count > 0) { 476 if (TimeLivenessAnalysis) _time_total.start(); 477 if (TimeLivenessAnalysis) _time_query.start(); 478 479 assert( 0 <= bci && bci < method()->code_size(), "bci out of range" ); 480 BasicBlock *block = _block_map->at(bci); 481 // We may not be at the block start, so search backwards to find the block 482 // containing bci. 483 int t = bci; 484 while (block == NULL && t > 0) { 485 block = _block_map->at(--t); 486 } 487 assert( block != NULL, "invalid bytecode index; must be instruction index" ); 488 assert(bci >= block->start_bci() && bci < block->limit_bci(), "block must contain bci."); 489 490 answer = block->get_liveness_at(method(), bci); 491 492 if (is_entry && method()->is_synchronized() && !method()->is_static()) { 493 // Synchronized methods use the receiver once on entry. 494 answer.at_put(0, true); 495 } 496 497#ifndef PRODUCT 498 if (TraceLivenessQuery) { 499 tty->print("Liveness query of "); 500 method()->print_short_name(); 501 tty->print(" @ %d : result is ", bci); 502 answer.print_on(tty); 503 } 504 505 if (TimeLivenessAnalysis) _time_query.stop(); 506 if (TimeLivenessAnalysis) _time_total.stop(); 507#endif 508 } 509 510#ifndef PRODUCT 511 if (TimeLivenessAnalysis) { 512 // Collect statistics. 513 _total_locals_queried += _bit_map_size_bits; 514 BitCounter counter; 515 answer.iterate(&counter); 516 _total_live_locals_queried += counter.count(); 517 } 518#endif 519 520 return answer; 521} 522 523 524#ifndef PRODUCT 525 526void MethodLiveness::print_times() { 527 tty->print_cr ("Accumulated liveness analysis times/statistics:"); 528 tty->print_cr ("-----------------------------------------------"); 529 tty->print_cr (" Total : %3.3f sec.", _time_total.seconds()); 530 tty->print_cr (" Build graph : %3.3f sec. (%2.2f%%)", _time_build_graph.seconds(), 531 _time_build_graph.seconds() * 100 / _time_total.seconds()); 532 tty->print_cr (" Gen / Kill : %3.3f sec. (%2.2f%%)", _time_gen_kill.seconds(), 533 _time_gen_kill.seconds() * 100 / _time_total.seconds()); 534 tty->print_cr (" Dataflow : %3.3f sec. (%2.2f%%)", _time_flow.seconds(), 535 _time_flow.seconds() * 100 / _time_total.seconds()); 536 tty->print_cr (" Query : %3.3f sec. (%2.2f%%)", _time_query.seconds(), 537 _time_query.seconds() * 100 / _time_total.seconds()); 538 tty->print_cr (" #bytes : %8ld (%3.0f bytes per sec)", 539 _total_bytes, 540 _total_bytes / _time_total.seconds()); 541 tty->print_cr (" #methods : %8d (%3.0f methods per sec)", 542 _total_methods, 543 _total_methods / _time_total.seconds()); 544 tty->print_cr (" avg locals : %3.3f max locals : %3d", 545 (float)_total_method_locals / _total_methods, 546 _max_method_locals); 547 tty->print_cr (" avg blocks : %3.3f max blocks : %3d", 548 (float)_total_blocks / _total_methods, 549 _max_method_blocks); 550 tty->print_cr (" avg bytes : %3.3f", 551 (float)_total_bytes / _total_methods); 552 tty->print_cr (" #blocks : %8ld", 553 _total_blocks); 554 tty->print_cr (" avg normal predecessors : %3.3f max normal predecessors : %3d", 555 (float)_total_edges / _total_blocks, 556 _max_block_edges); 557 tty->print_cr (" avg exception predecessors : %3.3f max exception predecessors : %3d", 558 (float)_total_exc_edges / _total_blocks, 559 _max_block_exc_edges); 560 tty->print_cr (" avg visits : %3.3f", 561 (float)_total_visits / _total_blocks); 562 tty->print_cr (" #locals queried : %8ld #live : %8ld %%live : %2.2f%%", 563 _total_locals_queried, 564 _total_live_locals_queried, 565 100.0 * _total_live_locals_queried / _total_locals_queried); 566} 567 568#endif 569 570 571MethodLiveness::BasicBlock::BasicBlock(MethodLiveness *analyzer, int start, int limit) : 572 _gen(analyzer->arena(), analyzer->bit_map_size_bits()), 573 _kill(analyzer->arena(), analyzer->bit_map_size_bits()), 574 _entry(analyzer->arena(), analyzer->bit_map_size_bits()), 575 _normal_exit(analyzer->arena(), analyzer->bit_map_size_bits()), 576 _exception_exit(analyzer->arena(), analyzer->bit_map_size_bits()), 577 _last_bci(-1) { 578 _analyzer = analyzer; 579 _start_bci = start; 580 _limit_bci = limit; 581 _normal_predecessors = 582 new (analyzer->arena()) GrowableArray<MethodLiveness::BasicBlock*>(analyzer->arena(), 5, 0, NULL); 583 _exception_predecessors = 584 new (analyzer->arena()) GrowableArray<MethodLiveness::BasicBlock*>(analyzer->arena(), 5, 0, NULL); 585} 586 587 588 589MethodLiveness::BasicBlock *MethodLiveness::BasicBlock::split(int split_bci) { 590 int start = _start_bci; 591 int limit = _limit_bci; 592 593 if (TraceLivenessGen) { 594 tty->print_cr(" ** Splitting block (%d,%d) at %d", start, limit, split_bci); 595 } 596 597 GrowableArray<BasicBlock*>* save_predecessors = _normal_predecessors; 598 599 assert (start < split_bci && split_bci < limit, "improper split"); 600 601 // Make a new block to cover the first half of the range. 602 BasicBlock *first_half = new (_analyzer->arena()) BasicBlock(_analyzer, start, split_bci); 603 604 // Assign correct values to the second half (this) 605 _normal_predecessors = first_half->_normal_predecessors; 606 _start_bci = split_bci; 607 add_normal_predecessor(first_half); 608 609 // Assign correct predecessors to the new first half 610 first_half->_normal_predecessors = save_predecessors; 611 612 return first_half; 613} 614 615void MethodLiveness::BasicBlock::compute_gen_kill(ciMethod* method) { 616 ciBytecodeStream bytes(method); 617 bytes.reset_to_bci(start_bci()); 618 bytes.set_max_bci(limit_bci()); 619 compute_gen_kill_range(&bytes); 620 621} 622 623void MethodLiveness::BasicBlock::compute_gen_kill_range(ciBytecodeStream *bytes) { 624 _gen.clear(); 625 _kill.clear(); 626 627 while (bytes->next() != ciBytecodeStream::EOBC()) { 628 compute_gen_kill_single(bytes); 629 } 630} 631 632void MethodLiveness::BasicBlock::compute_gen_kill_single(ciBytecodeStream *instruction) { 633 int localNum; 634 635 // We prohibit _gen and _kill from having locals in common. If we 636 // know that one is definitely going to be applied before the other, 637 // we could save some computation time by relaxing this prohibition. 638 639 switch (instruction->cur_bc()) { 640 case Bytecodes::_nop: 641 case Bytecodes::_goto: 642 case Bytecodes::_goto_w: 643 case Bytecodes::_aconst_null: 644 case Bytecodes::_new: 645 case Bytecodes::_iconst_m1: 646 case Bytecodes::_iconst_0: 647 case Bytecodes::_iconst_1: 648 case Bytecodes::_iconst_2: 649 case Bytecodes::_iconst_3: 650 case Bytecodes::_iconst_4: 651 case Bytecodes::_iconst_5: 652 case Bytecodes::_fconst_0: 653 case Bytecodes::_fconst_1: 654 case Bytecodes::_fconst_2: 655 case Bytecodes::_bipush: 656 case Bytecodes::_sipush: 657 case Bytecodes::_lconst_0: 658 case Bytecodes::_lconst_1: 659 case Bytecodes::_dconst_0: 660 case Bytecodes::_dconst_1: 661 case Bytecodes::_ldc2_w: 662 case Bytecodes::_ldc: 663 case Bytecodes::_ldc_w: 664 case Bytecodes::_iaload: 665 case Bytecodes::_faload: 666 case Bytecodes::_baload: 667 case Bytecodes::_caload: 668 case Bytecodes::_saload: 669 case Bytecodes::_laload: 670 case Bytecodes::_daload: 671 case Bytecodes::_aaload: 672 case Bytecodes::_iastore: 673 case Bytecodes::_fastore: 674 case Bytecodes::_bastore: 675 case Bytecodes::_castore: 676 case Bytecodes::_sastore: 677 case Bytecodes::_lastore: 678 case Bytecodes::_dastore: 679 case Bytecodes::_aastore: 680 case Bytecodes::_pop: 681 case Bytecodes::_pop2: 682 case Bytecodes::_dup: 683 case Bytecodes::_dup_x1: 684 case Bytecodes::_dup_x2: 685 case Bytecodes::_dup2: 686 case Bytecodes::_dup2_x1: 687 case Bytecodes::_dup2_x2: 688 case Bytecodes::_swap: 689 case Bytecodes::_iadd: 690 case Bytecodes::_fadd: 691 case Bytecodes::_isub: 692 case Bytecodes::_fsub: 693 case Bytecodes::_imul: 694 case Bytecodes::_fmul: 695 case Bytecodes::_idiv: 696 case Bytecodes::_fdiv: 697 case Bytecodes::_irem: 698 case Bytecodes::_frem: 699 case Bytecodes::_ishl: 700 case Bytecodes::_ishr: 701 case Bytecodes::_iushr: 702 case Bytecodes::_iand: 703 case Bytecodes::_ior: 704 case Bytecodes::_ixor: 705 case Bytecodes::_l2f: 706 case Bytecodes::_l2i: 707 case Bytecodes::_d2f: 708 case Bytecodes::_d2i: 709 case Bytecodes::_fcmpl: 710 case Bytecodes::_fcmpg: 711 case Bytecodes::_ladd: 712 case Bytecodes::_dadd: 713 case Bytecodes::_lsub: 714 case Bytecodes::_dsub: 715 case Bytecodes::_lmul: 716 case Bytecodes::_dmul: 717 case Bytecodes::_ldiv: 718 case Bytecodes::_ddiv: 719 case Bytecodes::_lrem: 720 case Bytecodes::_drem: 721 case Bytecodes::_land: 722 case Bytecodes::_lor: 723 case Bytecodes::_lxor: 724 case Bytecodes::_ineg: 725 case Bytecodes::_fneg: 726 case Bytecodes::_i2f: 727 case Bytecodes::_f2i: 728 case Bytecodes::_i2c: 729 case Bytecodes::_i2s: 730 case Bytecodes::_i2b: 731 case Bytecodes::_lneg: 732 case Bytecodes::_dneg: 733 case Bytecodes::_l2d: 734 case Bytecodes::_d2l: 735 case Bytecodes::_lshl: 736 case Bytecodes::_lshr: 737 case Bytecodes::_lushr: 738 case Bytecodes::_i2l: 739 case Bytecodes::_i2d: 740 case Bytecodes::_f2l: 741 case Bytecodes::_f2d: 742 case Bytecodes::_lcmp: 743 case Bytecodes::_dcmpl: 744 case Bytecodes::_dcmpg: 745 case Bytecodes::_ifeq: 746 case Bytecodes::_ifne: 747 case Bytecodes::_iflt: 748 case Bytecodes::_ifge: 749 case Bytecodes::_ifgt: 750 case Bytecodes::_ifle: 751 case Bytecodes::_tableswitch: 752 case Bytecodes::_ireturn: 753 case Bytecodes::_freturn: 754 case Bytecodes::_if_icmpeq: 755 case Bytecodes::_if_icmpne: 756 case Bytecodes::_if_icmplt: 757 case Bytecodes::_if_icmpge: 758 case Bytecodes::_if_icmpgt: 759 case Bytecodes::_if_icmple: 760 case Bytecodes::_lreturn: 761 case Bytecodes::_dreturn: 762 case Bytecodes::_if_acmpeq: 763 case Bytecodes::_if_acmpne: 764 case Bytecodes::_jsr: 765 case Bytecodes::_jsr_w: 766 case Bytecodes::_getstatic: 767 case Bytecodes::_putstatic: 768 case Bytecodes::_getfield: 769 case Bytecodes::_putfield: 770 case Bytecodes::_invokevirtual: 771 case Bytecodes::_invokespecial: 772 case Bytecodes::_invokestatic: 773 case Bytecodes::_invokeinterface: 774 case Bytecodes::_invokedynamic: 775 case Bytecodes::_newarray: 776 case Bytecodes::_anewarray: 777 case Bytecodes::_checkcast: 778 case Bytecodes::_arraylength: 779 case Bytecodes::_instanceof: 780 case Bytecodes::_athrow: 781 case Bytecodes::_areturn: 782 case Bytecodes::_monitorenter: 783 case Bytecodes::_monitorexit: 784 case Bytecodes::_ifnull: 785 case Bytecodes::_ifnonnull: 786 case Bytecodes::_multianewarray: 787 case Bytecodes::_lookupswitch: 788 // These bytecodes have no effect on the method's locals. 789 break; 790 791 case Bytecodes::_return: 792 if (instruction->method()->intrinsic_id() == vmIntrinsics::_Object_init) { 793 // return from Object.init implicitly registers a finalizer 794 // for the receiver if needed, so keep it alive. 795 load_one(0); 796 } 797 break; 798 799 800 case Bytecodes::_lload: 801 case Bytecodes::_dload: 802 load_two(instruction->get_index()); 803 break; 804 805 case Bytecodes::_lload_0: 806 case Bytecodes::_dload_0: 807 load_two(0); 808 break; 809 810 case Bytecodes::_lload_1: 811 case Bytecodes::_dload_1: 812 load_two(1); 813 break; 814 815 case Bytecodes::_lload_2: 816 case Bytecodes::_dload_2: 817 load_two(2); 818 break; 819 820 case Bytecodes::_lload_3: 821 case Bytecodes::_dload_3: 822 load_two(3); 823 break; 824 825 case Bytecodes::_iload: 826 case Bytecodes::_iinc: 827 case Bytecodes::_fload: 828 case Bytecodes::_aload: 829 case Bytecodes::_ret: 830 load_one(instruction->get_index()); 831 break; 832 833 case Bytecodes::_iload_0: 834 case Bytecodes::_fload_0: 835 case Bytecodes::_aload_0: 836 load_one(0); 837 break; 838 839 case Bytecodes::_iload_1: 840 case Bytecodes::_fload_1: 841 case Bytecodes::_aload_1: 842 load_one(1); 843 break; 844 845 case Bytecodes::_iload_2: 846 case Bytecodes::_fload_2: 847 case Bytecodes::_aload_2: 848 load_one(2); 849 break; 850 851 case Bytecodes::_iload_3: 852 case Bytecodes::_fload_3: 853 case Bytecodes::_aload_3: 854 load_one(3); 855 break; 856 857 case Bytecodes::_lstore: 858 case Bytecodes::_dstore: 859 store_two(localNum = instruction->get_index()); 860 break; 861 862 case Bytecodes::_lstore_0: 863 case Bytecodes::_dstore_0: 864 store_two(0); 865 break; 866 867 case Bytecodes::_lstore_1: 868 case Bytecodes::_dstore_1: 869 store_two(1); 870 break; 871 872 case Bytecodes::_lstore_2: 873 case Bytecodes::_dstore_2: 874 store_two(2); 875 break; 876 877 case Bytecodes::_lstore_3: 878 case Bytecodes::_dstore_3: 879 store_two(3); 880 break; 881 882 case Bytecodes::_istore: 883 case Bytecodes::_fstore: 884 case Bytecodes::_astore: 885 store_one(instruction->get_index()); 886 break; 887 888 case Bytecodes::_istore_0: 889 case Bytecodes::_fstore_0: 890 case Bytecodes::_astore_0: 891 store_one(0); 892 break; 893 894 case Bytecodes::_istore_1: 895 case Bytecodes::_fstore_1: 896 case Bytecodes::_astore_1: 897 store_one(1); 898 break; 899 900 case Bytecodes::_istore_2: 901 case Bytecodes::_fstore_2: 902 case Bytecodes::_astore_2: 903 store_one(2); 904 break; 905 906 case Bytecodes::_istore_3: 907 case Bytecodes::_fstore_3: 908 case Bytecodes::_astore_3: 909 store_one(3); 910 break; 911 912 case Bytecodes::_wide: 913 fatal("Iterator should skip this bytecode"); 914 break; 915 916 default: 917 tty->print("unexpected opcode: %d\n", instruction->cur_bc()); 918 ShouldNotReachHere(); 919 break; 920 } 921} 922 923void MethodLiveness::BasicBlock::load_two(int local) { 924 load_one(local); 925 load_one(local+1); 926} 927 928void MethodLiveness::BasicBlock::load_one(int local) { 929 if (!_kill.at(local)) { 930 _gen.at_put(local, true); 931 } 932} 933 934void MethodLiveness::BasicBlock::store_two(int local) { 935 store_one(local); 936 store_one(local+1); 937} 938 939void MethodLiveness::BasicBlock::store_one(int local) { 940 if (!_gen.at(local)) { 941 _kill.at_put(local, true); 942 } 943} 944 945void MethodLiveness::BasicBlock::propagate(MethodLiveness *ml) { 946 // These set operations could be combined for efficiency if the 947 // performance of this analysis becomes an issue. 948 _entry.set_union(_normal_exit); 949 _entry.set_difference(_kill); 950 _entry.set_union(_gen); 951 952 // Note that we merge information from our exceptional successors 953 // just once, rather than at individual bytecodes. 954 _entry.set_union(_exception_exit); 955 956 if (TraceLivenessGen) { 957 tty->print_cr(" ** Visiting block at %d **", start_bci()); 958 print_on(tty); 959 } 960 961 int i; 962 for (i=_normal_predecessors->length()-1; i>=0; i--) { 963 BasicBlock *block = _normal_predecessors->at(i); 964 if (block->merge_normal(_entry)) { 965 ml->work_list_add(block); 966 } 967 } 968 for (i=_exception_predecessors->length()-1; i>=0; i--) { 969 BasicBlock *block = _exception_predecessors->at(i); 970 if (block->merge_exception(_entry)) { 971 ml->work_list_add(block); 972 } 973 } 974} 975 976bool MethodLiveness::BasicBlock::merge_normal(const BitMap& other) { 977 return _normal_exit.set_union_with_result(other); 978} 979 980bool MethodLiveness::BasicBlock::merge_exception(const BitMap& other) { 981 return _exception_exit.set_union_with_result(other); 982} 983 984MethodLivenessResult MethodLiveness::BasicBlock::get_liveness_at(ciMethod* method, int bci) { 985 MethodLivenessResult answer(_analyzer->bit_map_size_bits()); 986 answer.set_is_valid(); 987 988#ifndef ASSERT 989 if (bci == start_bci()) { 990 answer.set_from(_entry); 991 return answer; 992 } 993#endif 994 995#ifdef ASSERT 996 ResourceMark rm; 997 ResourceBitMap g(_gen.size()); g.set_from(_gen); 998 ResourceBitMap k(_kill.size()); k.set_from(_kill); 999#endif 1000 if (_last_bci != bci || trueInDebug) { 1001 ciBytecodeStream bytes(method); 1002 bytes.reset_to_bci(bci); 1003 bytes.set_max_bci(limit_bci()); 1004 compute_gen_kill_range(&bytes); 1005 assert(_last_bci != bci || 1006 (g.is_same(_gen) && k.is_same(_kill)), "cached computation is incorrect"); 1007 _last_bci = bci; 1008 } 1009 1010 answer.set_union(_normal_exit); 1011 answer.set_difference(_kill); 1012 answer.set_union(_gen); 1013 answer.set_union(_exception_exit); 1014 1015#ifdef ASSERT 1016 if (bci == start_bci()) { 1017 assert(answer.is_same(_entry), "optimized answer must be accurate"); 1018 } 1019#endif 1020 1021 return answer; 1022} 1023 1024#ifndef PRODUCT 1025 1026void MethodLiveness::BasicBlock::print_on(outputStream *os) const { 1027 os->print_cr("==================================================================="); 1028 os->print_cr(" Block start: %4d, limit: %4d", _start_bci, _limit_bci); 1029 os->print (" Normal predecessors (%2d) @", _normal_predecessors->length()); 1030 int i; 1031 for (i=0; i < _normal_predecessors->length(); i++) { 1032 os->print(" %4d", _normal_predecessors->at(i)->start_bci()); 1033 } 1034 os->cr(); 1035 os->print (" Exceptional predecessors (%2d) @", _exception_predecessors->length()); 1036 for (i=0; i < _exception_predecessors->length(); i++) { 1037 os->print(" %4d", _exception_predecessors->at(i)->start_bci()); 1038 } 1039 os->cr(); 1040 os->print (" Normal Exit : "); 1041 _normal_exit.print_on(os); 1042 os->print (" Gen : "); 1043 _gen.print_on(os); 1044 os->print (" Kill : "); 1045 _kill.print_on(os); 1046 os->print (" Exception Exit: "); 1047 _exception_exit.print_on(os); 1048 os->print (" Entry : "); 1049 _entry.print_on(os); 1050} 1051 1052#endif // PRODUCT 1053