1 #ifdef USE_PRAGMA_IDENT_SRC 2 #pragma ident "@(#)c1_IR.cpp 1.161 08/11/07 15:47:10 JVM" 3 #endif 4 /* 5 * Copyright 1999-2008 Sun Microsystems, Inc. All Rights Reserved. 6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 7 * 8 * This code is free software; you can redistribute it and/or modify it 9 * under the terms of the GNU General Public License version 2 only, as 10 * published by the Free Software Foundation. 11 * 12 * This code is distributed in the hope that it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 * version 2 for more details (a copy is included in the LICENSE file that 16 * accompanied this code). 17 * 18 * You should have received a copy of the GNU General Public License version 19 * 2 along with this work; if not, write to the Free Software Foundation, 20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 21 * 22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 23 * CA 95054 USA or visit www.sun.com if you need additional information or 24 * have any questions. 25 * 26 */ 27 28 # include "incls/_precompiled.incl" 29 # include "incls/_c1_IR.cpp.incl" 30 31 32 // Implementation of XHandlers 33 // 34 // Note: This code could eventually go away if we are 35 // just using the ciExceptionHandlerStream. 36 37 XHandlers::XHandlers(ciMethod* method) : _list(method->exception_table_length()) { 38 ciExceptionHandlerStream s(method); 39 while (!s.is_done()) { 40 _list.append(new XHandler(s.handler())); 41 s.next(); 42 } 43 assert(s.count() == method->exception_table_length(), "exception table lengths inconsistent"); 44 } 45 46 // deep copy of all XHandler contained in list 47 XHandlers::XHandlers(XHandlers* other) : 48 _list(other->length()) 49 { 50 for (int i = 0; i < other->length(); i++) { 51 _list.append(new XHandler(other->handler_at(i))); 52 } 53 } 54 55 // Returns whether a particular exception type can be caught. Also 56 // returns true if klass is unloaded or any exception handler 57 // classes are unloaded. type_is_exact indicates whether the throw 58 // is known to be exactly that class or it might throw a subtype. 59 bool XHandlers::could_catch(ciInstanceKlass* klass, bool type_is_exact) const { 60 // the type is unknown so be conservative 61 if (!klass->is_loaded()) { 62 return true; 63 } 64 65 for (int i = 0; i < length(); i++) { 66 XHandler* handler = handler_at(i); 67 if (handler->is_catch_all()) { 68 // catch of ANY 69 return true; 70 } 71 ciInstanceKlass* handler_klass = handler->catch_klass(); 72 // if it's unknown it might be catchable 73 if (!handler_klass->is_loaded()) { 74 return true; 75 } 76 // if the throw type is definitely a subtype of the catch type 77 // then it can be caught. 78 if (klass->is_subtype_of(handler_klass)) { 79 return true; 80 } 81 if (!type_is_exact) { 82 // If the type isn't exactly known then it can also be caught by 83 // catch statements where the inexact type is a subtype of the 84 // catch type. 85 // given: foo extends bar extends Exception 86 // throw bar can be caught by catch foo, catch bar, and catch 87 // Exception, however it can't be caught by any handlers without 88 // bar in its type hierarchy. 89 if (handler_klass->is_subtype_of(klass)) { 90 return true; 91 } 92 } 93 } 94 95 return false; 96 } 97 98 99 bool XHandlers::equals(XHandlers* others) const { 100 if (others == NULL) return false; 101 if (length() != others->length()) return false; 102 103 for (int i = 0; i < length(); i++) { 104 if (!handler_at(i)->equals(others->handler_at(i))) return false; 105 } 106 return true; 107 } 108 109 bool XHandler::equals(XHandler* other) const { 110 assert(entry_pco() != -1 && other->entry_pco() != -1, "must have entry_pco"); 111 112 if (entry_pco() != other->entry_pco()) return false; 113 if (scope_count() != other->scope_count()) return false; 114 if (_desc != other->_desc) return false; 115 116 assert(entry_block() == other->entry_block(), "entry_block must be equal when entry_pco is equal"); 117 return true; 118 } 119 120 121 // Implementation of IRScope 122 123 BlockBegin* IRScope::header_block(BlockBegin* entry, BlockBegin::Flag f, ValueStack* state) { 124 if (entry == NULL) return NULL; 125 assert(entry->is_set(f), "entry/flag mismatch"); 126 // create header block 127 BlockBegin* h = new BlockBegin(entry->bci()); 128 BlockEnd* g = new Goto(entry, false); 129 h->set_next(g, entry->bci()); 130 h->set_end(g); 131 h->set(f); 132 // setup header block end state 133 ValueStack* s = state->copy(); // can use copy since stack is empty (=> no phis) 134 assert(s->stack_is_empty(), "must have empty stack at entry point"); 135 g->set_state(s); 136 return h; 137 } 138 139 140 BlockBegin* IRScope::build_graph(Compilation* compilation, int osr_bci) { 141 GraphBuilder gm(compilation, this); 142 NOT_PRODUCT(if (PrintValueNumbering && Verbose) gm.print_stats()); 143 if (compilation->bailed_out()) return NULL; 144 return gm.start(); 145 } 146 147 148 IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMethod* method, int osr_bci, bool create_graph) 149 : _callees(2) 150 , _compilation(compilation) 151 , _lock_stack_size(-1) 152 , _requires_phi_function(method->max_locals()) 153 { 154 _caller = caller; 155 _caller_bci = caller == NULL ? -1 : caller_bci; 156 _caller_state = NULL; // Must be set later if needed 157 _level = caller == NULL ? 0 : caller->level() + 1; 158 _method = method; 159 _xhandlers = new XHandlers(method); 160 _number_of_locks = 0; 161 _monitor_pairing_ok = method->has_balanced_monitors(); 162 _start = NULL; 163 164 if (osr_bci == -1) { 165 _requires_phi_function.clear(); 166 } else { 167 // selective creation of phi functions is not possibel in osr-methods 168 _requires_phi_function.set_range(0, method->max_locals()); 169 } 170 171 assert(method->holder()->is_loaded() , "method holder must be loaded"); 172 173 // build graph if monitor pairing is ok 174 if (create_graph && monitor_pairing_ok()) _start = build_graph(compilation, osr_bci); 175 } 176 177 178 int IRScope::max_stack() const { 179 int my_max = method()->max_stack(); 180 int callee_max = 0; 181 for (int i = 0; i < number_of_callees(); i++) { 182 callee_max = MAX2(callee_max, callee_no(i)->max_stack()); 183 } 184 return my_max + callee_max; 185 } 186 187 188 void IRScope::compute_lock_stack_size() { 189 if (!InlineMethodsWithExceptionHandlers) { 190 _lock_stack_size = 0; 191 return; 192 } 193 194 // Figure out whether we have to preserve expression stack elements 195 // for parent scopes, and if so, how many 196 IRScope* cur_scope = this; 197 while (cur_scope != NULL && !cur_scope->xhandlers()->has_handlers()) { 198 cur_scope = cur_scope->caller(); 199 } 200 _lock_stack_size = (cur_scope == NULL ? 0 : 201 (cur_scope->caller_state() == NULL ? 0 : 202 cur_scope->caller_state()->stack_size())); 203 } 204 205 int IRScope::top_scope_bci() const { 206 assert(!is_top_scope(), "no correct answer for top scope possible"); 207 const IRScope* scope = this; 208 while (!scope->caller()->is_top_scope()) { 209 scope = scope->caller(); 210 } 211 return scope->caller_bci(); 212 } 213 214 215 216 // Implementation of CodeEmitInfo 217 218 // Stack must be NON-null 219 CodeEmitInfo::CodeEmitInfo(int bci, ValueStack* stack, XHandlers* exception_handlers) 220 : _scope(stack->scope()) 221 , _bci(bci) 222 , _scope_debug_info(NULL) 223 , _oop_map(NULL) 224 , _stack(stack) 225 , _exception_handlers(exception_handlers) 226 , _next(NULL) 227 , _id(-1) { 228 assert(_stack != NULL, "must be non null"); 229 assert(_bci == SynchronizationEntryBCI || Bytecodes::is_defined(scope()->method()->java_code_at_bci(_bci)), "make sure bci points at a real bytecode"); 230 } 231 232 233 CodeEmitInfo::CodeEmitInfo(CodeEmitInfo* info, bool lock_stack_only) 234 : _scope(info->_scope) 235 , _exception_handlers(NULL) 236 , _bci(info->_bci) 237 , _scope_debug_info(NULL) 238 , _oop_map(NULL) { 239 if (lock_stack_only) { 240 if (info->_stack != NULL) { 241 _stack = info->_stack->copy_locks(); 242 } else { 243 _stack = NULL; 244 } 245 } else { 246 _stack = info->_stack; 247 } 248 249 // deep copy of exception handlers 250 if (info->_exception_handlers != NULL) { 251 _exception_handlers = new XHandlers(info->_exception_handlers); 252 } 253 } 254 255 256 void CodeEmitInfo::record_debug_info(DebugInformationRecorder* recorder, int pc_offset) { 257 // record the safepoint before recording the debug info for enclosing scopes 258 recorder->add_safepoint(pc_offset, _oop_map->deep_copy()); 259 _scope_debug_info->record_debug_info(recorder, pc_offset); 260 recorder->end_safepoint(pc_offset); 261 } 262 263 264 void CodeEmitInfo::add_register_oop(LIR_Opr opr) { 265 assert(_oop_map != NULL, "oop map must already exist"); 266 assert(opr->is_single_cpu(), "should not call otherwise"); 267 268 int frame_size = frame_map()->framesize(); 269 int arg_count = frame_map()->oop_map_arg_count(); 270 VMReg name = frame_map()->regname(opr); 271 _oop_map->set_oop(name); 272 } 273 274 275 276 277 // Implementation of IR 278 279 IR::IR(Compilation* compilation, ciMethod* method, int osr_bci) : 280 _locals_size(in_WordSize(-1)) 281 , _num_loops(0) { 282 // initialize data structures 283 ValueType::initialize(); 284 Instruction::initialize(); 285 BlockBegin::initialize(); 286 GraphBuilder::initialize(); 287 // setup IR fields 288 _compilation = compilation; 289 _top_scope = new IRScope(compilation, NULL, -1, method, osr_bci, true); 290 _code = NULL; 291 } 292 293 294 void IR::optimize() { 295 Optimizer opt(this); 296 if (DoCEE) { 297 opt.eliminate_conditional_expressions(); 298 #ifndef PRODUCT 299 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after CEE"); print(true); } 300 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after CEE"); print(false); } 301 #endif 302 } 303 if (EliminateBlocks) { 304 opt.eliminate_blocks(); 305 #ifndef PRODUCT 306 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after block elimination"); print(true); } 307 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after block elimination"); print(false); } 308 #endif 309 } 310 if (EliminateNullChecks) { 311 opt.eliminate_null_checks(); 312 #ifndef PRODUCT 313 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after null check elimination"); print(true); } 314 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after null check elimination"); print(false); } 315 #endif 316 } 317 } 318 319 320 static int sort_pairs(BlockPair** a, BlockPair** b) { 321 if ((*a)->from() == (*b)->from()) { 322 return (*a)->to()->block_id() - (*b)->to()->block_id(); 323 } else { 324 return (*a)->from()->block_id() - (*b)->from()->block_id(); 325 } 326 } 327 328 329 class CriticalEdgeFinder: public BlockClosure { 330 BlockPairList blocks; 331 IR* _ir; 332 333 public: 334 CriticalEdgeFinder(IR* ir): _ir(ir) {} 335 void block_do(BlockBegin* bb) { 336 BlockEnd* be = bb->end(); 337 int nos = be->number_of_sux(); 338 if (nos >= 2) { 339 for (int i = 0; i < nos; i++) { 340 BlockBegin* sux = be->sux_at(i); 341 if (sux->number_of_preds() >= 2) { 342 blocks.append(new BlockPair(bb, sux)); 343 } 344 } 345 } 346 } 347 348 void split_edges() { 349 BlockPair* last_pair = NULL; 350 blocks.sort(sort_pairs); 351 for (int i = 0; i < blocks.length(); i++) { 352 BlockPair* pair = blocks.at(i); 353 if (last_pair != NULL && pair->is_same(last_pair)) continue; 354 BlockBegin* from = pair->from(); 355 BlockBegin* to = pair->to(); 356 BlockBegin* split = from->insert_block_between(to); 357 #ifndef PRODUCT 358 if ((PrintIR || PrintIR1) && Verbose) { 359 tty->print_cr("Split critical edge B%d -> B%d (new block B%d)", 360 from->block_id(), to->block_id(), split->block_id()); 361 } 362 #endif 363 last_pair = pair; 364 } 365 } 366 }; 367 368 void IR::split_critical_edges() { 369 CriticalEdgeFinder cef(this); 370 371 iterate_preorder(&cef); 372 cef.split_edges(); 373 } 374 375 376 class UseCountComputer: public AllStatic { 377 private: 378 static void update_use_count(Value* n) { 379 // Local instructions and Phis for expression stack values at the 380 // start of basic blocks are not added to the instruction list 381 if ((*n)->bci() == -99 && (*n)->as_Local() == NULL && 382 (*n)->as_Phi() == NULL) { 383 assert(false, "a node was not appended to the graph"); 384 Compilation::current_compilation()->bailout("a node was not appended to the graph"); 385 } 386 // use n's input if not visited before 387 if (!(*n)->is_pinned() && !(*n)->has_uses()) { 388 // note: a) if the instruction is pinned, it will be handled by compute_use_count 389 // b) if the instruction has uses, it was touched before 390 // => in both cases we don't need to update n's values 391 uses_do(n); 392 } 393 // use n 394 (*n)->_use_count++; 395 } 396 397 static Values* worklist; 398 static int depth; 399 enum { 400 max_recurse_depth = 20 401 }; 402 403 static void uses_do(Value* n) { 404 depth++; 405 if (depth > max_recurse_depth) { 406 // don't allow the traversal to recurse too deeply 407 worklist->push(*n); 408 } else { 409 (*n)->input_values_do(update_use_count); 410 // special handling for some instructions 411 if ((*n)->as_BlockEnd() != NULL) { 412 // note on BlockEnd: 413 // must 'use' the stack only if the method doesn't 414 // terminate, however, in those cases stack is empty 415 (*n)->state_values_do(update_use_count); 416 } 417 } 418 depth--; 419 } 420 421 static void basic_compute_use_count(BlockBegin* b) { 422 depth = 0; 423 // process all pinned nodes as the roots of expression trees 424 for (Instruction* n = b; n != NULL; n = n->next()) { 425 if (n->is_pinned()) uses_do(&n); 426 } 427 assert(depth == 0, "should have counted back down"); 428 429 // now process any unpinned nodes which recursed too deeply 430 while (worklist->length() > 0) { 431 Value t = worklist->pop(); 432 if (!t->is_pinned()) { 433 // compute the use count 434 uses_do(&t); 435 436 // pin the instruction so that LIRGenerator doesn't recurse 437 // too deeply during it's evaluation. 438 t->pin(); 439 } 440 } 441 assert(depth == 0, "should have counted back down"); 442 } 443 444 public: 445 static void compute(BlockList* blocks) { 446 worklist = new Values(); 447 blocks->blocks_do(basic_compute_use_count); 448 worklist = NULL; 449 } 450 }; 451 452 453 Values* UseCountComputer::worklist = NULL; 454 int UseCountComputer::depth = 0; 455 456 // helper macro for short definition of trace-output inside code 457 #ifndef PRODUCT 458 #define TRACE_LINEAR_SCAN(level, code) \ 459 if (TraceLinearScanLevel >= level) { \ 460 code; \ 461 } 462 #else 463 #define TRACE_LINEAR_SCAN(level, code) 464 #endif 465 466 class ComputeLinearScanOrder : public StackObj { 467 private: 468 int _max_block_id; // the highest block_id of a block 469 int _num_blocks; // total number of blocks (smaller than _max_block_id) 470 int _num_loops; // total number of loops 471 bool _iterative_dominators;// method requires iterative computation of dominatiors 472 473 BlockList* _linear_scan_order; // the resulting list of blocks in correct order 474 475 BitMap _visited_blocks; // used for recursive processing of blocks 476 BitMap _active_blocks; // used for recursive processing of blocks 477 BitMap _dominator_blocks; // temproary BitMap used for computation of dominator 478 intArray _forward_branches; // number of incoming forward branches for each block 479 BlockList _loop_end_blocks; // list of all loop end blocks collected during count_edges 480 BitMap2D _loop_map; // two-dimensional bit set: a bit is set if a block is contained in a loop 481 BlockList _work_list; // temporary list (used in mark_loops and compute_order) 482 483 // accessors for _visited_blocks and _active_blocks 484 void init_visited() { _active_blocks.clear(); _visited_blocks.clear(); } 485 bool is_visited(BlockBegin* b) const { return _visited_blocks.at(b->block_id()); } 486 bool is_active(BlockBegin* b) const { return _active_blocks.at(b->block_id()); } 487 void set_visited(BlockBegin* b) { assert(!is_visited(b), "already set"); _visited_blocks.set_bit(b->block_id()); } 488 void set_active(BlockBegin* b) { assert(!is_active(b), "already set"); _active_blocks.set_bit(b->block_id()); } 489 void clear_active(BlockBegin* b) { assert(is_active(b), "not already"); _active_blocks.clear_bit(b->block_id()); } 490 491 // accessors for _forward_branches 492 void inc_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) + 1); } 493 int dec_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) - 1); return _forward_branches.at(b->block_id()); } 494 495 // accessors for _loop_map 496 bool is_block_in_loop (int loop_idx, BlockBegin* b) const { return _loop_map.at(loop_idx, b->block_id()); } 497 void set_block_in_loop (int loop_idx, BlockBegin* b) { _loop_map.set_bit(loop_idx, b->block_id()); } 498 void clear_block_in_loop(int loop_idx, int block_id) { _loop_map.clear_bit(loop_idx, block_id); } 499 500 // count edges between blocks 501 void count_edges(BlockBegin* cur, BlockBegin* parent); 502 503 // loop detection 504 void mark_loops(); 505 void clear_non_natural_loops(BlockBegin* start_block); 506 void assign_loop_depth(BlockBegin* start_block); 507 508 // computation of final block order 509 BlockBegin* common_dominator(BlockBegin* a, BlockBegin* b); 510 void compute_dominator(BlockBegin* cur, BlockBegin* parent); 511 int compute_weight(BlockBegin* cur); 512 bool ready_for_processing(BlockBegin* cur); 513 void sort_into_work_list(BlockBegin* b); 514 void append_block(BlockBegin* cur); 515 void compute_order(BlockBegin* start_block); 516 517 // fixup of dominators for non-natural loops 518 bool compute_dominators_iter(); 519 void compute_dominators(); 520 521 // debug functions 522 NOT_PRODUCT(void print_blocks();) 523 DEBUG_ONLY(void verify();) 524 525 public: 526 ComputeLinearScanOrder(BlockBegin* start_block); 527 528 // accessors for final result 529 BlockList* linear_scan_order() const { return _linear_scan_order; } 530 int num_loops() const { return _num_loops; } 531 }; 532 533 534 ComputeLinearScanOrder::ComputeLinearScanOrder(BlockBegin* start_block) : 535 _max_block_id(BlockBegin::number_of_blocks()), 536 _num_blocks(0), 537 _num_loops(0), 538 _iterative_dominators(false), 539 _visited_blocks(_max_block_id), 540 _active_blocks(_max_block_id), 541 _dominator_blocks(_max_block_id), 542 _forward_branches(_max_block_id, 0), 543 _loop_end_blocks(8), 544 _work_list(8), 545 _linear_scan_order(NULL), // initialized later with correct size 546 _loop_map(0, 0) // initialized later with correct size 547 { 548 TRACE_LINEAR_SCAN(2, "***** computing linear-scan block order"); 549 550 init_visited(); 551 count_edges(start_block, NULL); 552 553 if (_num_loops > 0) { 554 mark_loops(); 555 clear_non_natural_loops(start_block); 556 assign_loop_depth(start_block); 557 } 558 559 compute_order(start_block); 560 compute_dominators(); 561 562 NOT_PRODUCT(print_blocks()); 563 DEBUG_ONLY(verify()); 564 } 565 566 567 // Traverse the CFG: 568 // * count total number of blocks 569 // * count all incoming edges and backward incoming edges 570 // * number loop header blocks 571 // * create a list with all loop end blocks 572 void ComputeLinearScanOrder::count_edges(BlockBegin* cur, BlockBegin* parent) { 573 TRACE_LINEAR_SCAN(3, tty->print_cr("Enter count_edges for block B%d coming from B%d", cur->block_id(), parent != NULL ? parent->block_id() : -1)); 574 assert(cur->dominator() == NULL, "dominator already initialized"); 575 576 if (is_active(cur)) { 577 TRACE_LINEAR_SCAN(3, tty->print_cr("backward branch")); 578 assert(is_visited(cur), "block must be visisted when block is active"); 579 assert(parent != NULL, "must have parent"); 580 581 cur->set(BlockBegin::linear_scan_loop_header_flag); 582 cur->set(BlockBegin::backward_branch_target_flag); 583 584 parent->set(BlockBegin::linear_scan_loop_end_flag); 585 586 // When a loop header is also the start of an exception handler, then the backward branch is 587 // an exception edge. Because such edges are usually critical edges which cannot be split, the 588 // loop must be excluded here from processing. 589 if (cur->is_set(BlockBegin::exception_entry_flag)) { 590 // Make sure that dominators are correct in this weird situation 591 _iterative_dominators = true; 592 return; 593 } 594 assert(parent->number_of_sux() == 1 && parent->sux_at(0) == cur, 595 "loop end blocks must have one successor (critical edges are split)"); 596 597 _loop_end_blocks.append(parent); 598 return; 599 } 600 601 // increment number of incoming forward branches 602 inc_forward_branches(cur); 603 604 if (is_visited(cur)) { 605 TRACE_LINEAR_SCAN(3, tty->print_cr("block already visited")); 606 return; 607 } 608 609 _num_blocks++; 610 set_visited(cur); 611 set_active(cur); 612 613 // recursive call for all successors 614 int i; 615 for (i = cur->number_of_sux() - 1; i >= 0; i--) { 616 count_edges(cur->sux_at(i), cur); 617 } 618 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { 619 count_edges(cur->exception_handler_at(i), cur); 620 } 621 622 clear_active(cur); 623 624 // Each loop has a unique number. 625 // When multiple loops are nested, assign_loop_depth assumes that the 626 // innermost loop has the lowest number. This is guaranteed by setting 627 // the loop number after the recursive calls for the successors above 628 // have returned. 629 if (cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { 630 assert(cur->loop_index() == -1, "cannot set loop-index twice"); 631 TRACE_LINEAR_SCAN(3, tty->print_cr("Block B%d is loop header of loop %d", cur->block_id(), _num_loops)); 632 633 cur->set_loop_index(_num_loops); 634 _num_loops++; 635 } 636 637 TRACE_LINEAR_SCAN(3, tty->print_cr("Finished count_edges for block B%d", cur->block_id())); 638 } 639 640 641 void ComputeLinearScanOrder::mark_loops() { 642 TRACE_LINEAR_SCAN(3, tty->print_cr("----- marking loops")); 643 644 _loop_map = BitMap2D(_num_loops, _max_block_id); 645 _loop_map.clear(); 646 647 for (int i = _loop_end_blocks.length() - 1; i >= 0; i--) { 648 BlockBegin* loop_end = _loop_end_blocks.at(i); 649 BlockBegin* loop_start = loop_end->sux_at(0); 650 int loop_idx = loop_start->loop_index(); 651 652 TRACE_LINEAR_SCAN(3, tty->print_cr("Processing loop from B%d to B%d (loop %d):", loop_start->block_id(), loop_end->block_id(), loop_idx)); 653 assert(loop_end->is_set(BlockBegin::linear_scan_loop_end_flag), "loop end flag must be set"); 654 assert(loop_end->number_of_sux() == 1, "incorrect number of successors"); 655 assert(loop_start->is_set(BlockBegin::linear_scan_loop_header_flag), "loop header flag must be set"); 656 assert(loop_idx >= 0 && loop_idx < _num_loops, "loop index not set"); 657 assert(_work_list.is_empty(), "work list must be empty before processing"); 658 659 // add the end-block of the loop to the working list 660 _work_list.push(loop_end); 661 set_block_in_loop(loop_idx, loop_end); 662 do { 663 BlockBegin* cur = _work_list.pop(); 664 665 TRACE_LINEAR_SCAN(3, tty->print_cr(" processing B%d", cur->block_id())); 666 assert(is_block_in_loop(loop_idx, cur), "bit in loop map must be set when block is in work list"); 667 668 // recursive processing of all predecessors ends when start block of loop is reached 669 if (cur != loop_start && !cur->is_set(BlockBegin::osr_entry_flag)) { 670 for (int j = cur->number_of_preds() - 1; j >= 0; j--) { 671 BlockBegin* pred = cur->pred_at(j); 672 673 if (!is_block_in_loop(loop_idx, pred) /*&& !pred->is_set(BlockBeginosr_entry_flag)*/) { 674 // this predecessor has not been processed yet, so add it to work list 675 TRACE_LINEAR_SCAN(3, tty->print_cr(" pushing B%d", pred->block_id())); 676 _work_list.push(pred); 677 set_block_in_loop(loop_idx, pred); 678 } 679 } 680 } 681 } while (!_work_list.is_empty()); 682 } 683 } 684 685 686 // check for non-natural loops (loops where the loop header does not dominate 687 // all other loop blocks = loops with mulitple entries). 688 // such loops are ignored 689 void ComputeLinearScanOrder::clear_non_natural_loops(BlockBegin* start_block) { 690 for (int i = _num_loops - 1; i >= 0; i--) { 691 if (is_block_in_loop(i, start_block)) { 692 // loop i contains the entry block of the method 693 // -> this is not a natural loop, so ignore it 694 TRACE_LINEAR_SCAN(2, tty->print_cr("Loop %d is non-natural, so it is ignored", i)); 695 696 for (int block_id = _max_block_id - 1; block_id >= 0; block_id--) { 697 clear_block_in_loop(i, block_id); 698 } 699 _iterative_dominators = true; 700 } 701 } 702 } 703 704 void ComputeLinearScanOrder::assign_loop_depth(BlockBegin* start_block) { 705 TRACE_LINEAR_SCAN(3, "----- computing loop-depth and weight"); 706 init_visited(); 707 708 assert(_work_list.is_empty(), "work list must be empty before processing"); 709 _work_list.append(start_block); 710 711 do { 712 BlockBegin* cur = _work_list.pop(); 713 714 if (!is_visited(cur)) { 715 set_visited(cur); 716 TRACE_LINEAR_SCAN(4, tty->print_cr("Computing loop depth for block B%d", cur->block_id())); 717 718 // compute loop-depth and loop-index for the block 719 assert(cur->loop_depth() == 0, "cannot set loop-depth twice"); 720 int i; 721 int loop_depth = 0; 722 int min_loop_idx = -1; 723 for (i = _num_loops - 1; i >= 0; i--) { 724 if (is_block_in_loop(i, cur)) { 725 loop_depth++; 726 min_loop_idx = i; 727 } 728 } 729 cur->set_loop_depth(loop_depth); 730 cur->set_loop_index(min_loop_idx); 731 732 // append all unvisited successors to work list 733 for (i = cur->number_of_sux() - 1; i >= 0; i--) { 734 _work_list.append(cur->sux_at(i)); 735 } 736 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { 737 _work_list.append(cur->exception_handler_at(i)); 738 } 739 } 740 } while (!_work_list.is_empty()); 741 } 742 743 744 BlockBegin* ComputeLinearScanOrder::common_dominator(BlockBegin* a, BlockBegin* b) { 745 assert(a != NULL && b != NULL, "must have input blocks"); 746 747 _dominator_blocks.clear(); 748 while (a != NULL) { 749 _dominator_blocks.set_bit(a->block_id()); 750 assert(a->dominator() != NULL || a == _linear_scan_order->at(0), "dominator must be initialized"); 751 a = a->dominator(); 752 } 753 while (b != NULL && !_dominator_blocks.at(b->block_id())) { 754 assert(b->dominator() != NULL || b == _linear_scan_order->at(0), "dominator must be initialized"); 755 b = b->dominator(); 756 } 757 758 assert(b != NULL, "could not find dominator"); 759 return b; 760 } 761 762 void ComputeLinearScanOrder::compute_dominator(BlockBegin* cur, BlockBegin* parent) { 763 if (cur->dominator() == NULL) { 764 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: initializing dominator of B%d to B%d", cur->block_id(), parent->block_id())); 765 cur->set_dominator(parent); 766 767 } else if (!(cur->is_set(BlockBegin::linear_scan_loop_header_flag) && parent->is_set(BlockBegin::linear_scan_loop_end_flag))) { 768 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: computing dominator of B%d: common dominator of B%d and B%d is B%d", cur->block_id(), parent->block_id(), cur->dominator()->block_id(), common_dominator(cur->dominator(), parent)->block_id())); 769 assert(cur->number_of_preds() > 1, ""); 770 cur->set_dominator(common_dominator(cur->dominator(), parent)); 771 } 772 } 773 774 775 int ComputeLinearScanOrder::compute_weight(BlockBegin* cur) { 776 BlockBegin* single_sux = NULL; 777 if (cur->number_of_sux() == 1) { 778 single_sux = cur->sux_at(0); 779 } 780 781 // limit loop-depth to 15 bit (only for security reason, it will never be so big) 782 int weight = (cur->loop_depth() & 0x7FFF) << 16; 783 784 // general macro for short definition of weight flags 785 // the first instance of INC_WEIGHT_IF has the highest priority 786 int cur_bit = 15; 787 #define INC_WEIGHT_IF(condition) if ((condition)) { weight |= (1 << cur_bit); } cur_bit--; 788 789 // this is necessery for the (very rare) case that two successing blocks have 790 // the same loop depth, but a different loop index (can happen for endless loops 791 // with exception handlers) 792 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_header_flag)); 793 794 // loop end blocks (blocks that end with a backward branch) are added 795 // after all other blocks of the loop. 796 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_end_flag)); 797 798 // critical edge split blocks are prefered because than they have a bigger 799 // proability to be completely empty 800 INC_WEIGHT_IF(cur->is_set(BlockBegin::critical_edge_split_flag)); 801 802 // exceptions should not be thrown in normal control flow, so these blocks 803 // are added as late as possible 804 INC_WEIGHT_IF(cur->end()->as_Throw() == NULL && (single_sux == NULL || single_sux->end()->as_Throw() == NULL)); 805 INC_WEIGHT_IF(cur->end()->as_Return() == NULL && (single_sux == NULL || single_sux->end()->as_Return() == NULL)); 806 807 // exceptions handlers are added as late as possible 808 INC_WEIGHT_IF(!cur->is_set(BlockBegin::exception_entry_flag)); 809 810 // guarantee that weight is > 0 811 weight |= 1; 812 813 #undef INC_WEIGHT_IF 814 assert(cur_bit >= 0, "too many flags"); 815 assert(weight > 0, "weight cannot become negative"); 816 817 return weight; 818 } 819 820 bool ComputeLinearScanOrder::ready_for_processing(BlockBegin* cur) { 821 // Discount the edge just traveled. 822 // When the number drops to zero, all forward branches were processed 823 if (dec_forward_branches(cur) != 0) { 824 return false; 825 } 826 827 assert(_linear_scan_order->index_of(cur) == -1, "block already processed (block can be ready only once)"); 828 assert(_work_list.index_of(cur) == -1, "block already in work-list (block can be ready only once)"); 829 return true; 830 } 831 832 void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) { 833 assert(_work_list.index_of(cur) == -1, "block already in work list"); 834 835 int cur_weight = compute_weight(cur); 836 837 // the linear_scan_number is used to cache the weight of a block 838 cur->set_linear_scan_number(cur_weight); 839 840 #ifndef PRODUCT 841 if (StressLinearScan) { 842 _work_list.insert_before(0, cur); 843 return; 844 } 845 #endif 846 847 _work_list.append(NULL); // provide space for new element 848 849 int insert_idx = _work_list.length() - 1; 850 while (insert_idx > 0 && _work_list.at(insert_idx - 1)->linear_scan_number() > cur_weight) { 851 _work_list.at_put(insert_idx, _work_list.at(insert_idx - 1)); 852 insert_idx--; 853 } 854 _work_list.at_put(insert_idx, cur); 855 856 TRACE_LINEAR_SCAN(3, tty->print_cr("Sorted B%d into worklist. new worklist:", cur->block_id())); 857 TRACE_LINEAR_SCAN(3, for (int i = 0; i < _work_list.length(); i++) tty->print_cr("%8d B%2d weight:%6x", i, _work_list.at(i)->block_id(), _work_list.at(i)->linear_scan_number())); 858 859 #ifdef ASSERT 860 for (int i = 0; i < _work_list.length(); i++) { 861 assert(_work_list.at(i)->linear_scan_number() > 0, "weight not set"); 862 assert(i == 0 || _work_list.at(i - 1)->linear_scan_number() <= _work_list.at(i)->linear_scan_number(), "incorrect order in worklist"); 863 } 864 #endif 865 } 866 867 void ComputeLinearScanOrder::append_block(BlockBegin* cur) { 868 TRACE_LINEAR_SCAN(3, tty->print_cr("appending block B%d (weight 0x%6x) to linear-scan order", cur->block_id(), cur->linear_scan_number())); 869 assert(_linear_scan_order->index_of(cur) == -1, "cannot add the same block twice"); 870 871 // currently, the linear scan order and code emit order are equal. 872 // therefore the linear_scan_number and the weight of a block must also 873 // be equal. 874 cur->set_linear_scan_number(_linear_scan_order->length()); 875 _linear_scan_order->append(cur); 876 } 877 878 void ComputeLinearScanOrder::compute_order(BlockBegin* start_block) { 879 TRACE_LINEAR_SCAN(3, "----- computing final block order"); 880 881 // the start block is always the first block in the linear scan order 882 _linear_scan_order = new BlockList(_num_blocks); 883 append_block(start_block); 884 885 assert(start_block->end()->as_Base() != NULL, "start block must end with Base-instruction"); 886 BlockBegin* std_entry = ((Base*)start_block->end())->std_entry(); 887 BlockBegin* osr_entry = ((Base*)start_block->end())->osr_entry(); 888 889 BlockBegin* sux_of_osr_entry = NULL; 890 if (osr_entry != NULL) { 891 // special handling for osr entry: 892 // ignore the edge between the osr entry and its successor for processing 893 // the osr entry block is added manually below 894 assert(osr_entry->number_of_sux() == 1, "osr entry must have exactly one successor"); 895 assert(osr_entry->sux_at(0)->number_of_preds() >= 2, "sucessor of osr entry must have two predecessors (otherwise it is not present in normal control flow"); 896 897 sux_of_osr_entry = osr_entry->sux_at(0); 898 dec_forward_branches(sux_of_osr_entry); 899 900 compute_dominator(osr_entry, start_block); 901 _iterative_dominators = true; 902 } 903 compute_dominator(std_entry, start_block); 904 905 // start processing with standard entry block 906 assert(_work_list.is_empty(), "list must be empty before processing"); 907 908 if (ready_for_processing(std_entry)) { 909 sort_into_work_list(std_entry); 910 } else { 911 assert(false, "the std_entry must be ready for processing (otherwise, the method has no start block)"); 912 } 913 914 do { 915 BlockBegin* cur = _work_list.pop(); 916 917 if (cur == sux_of_osr_entry) { 918 // the osr entry block is ignored in normal processing, it is never added to the 919 // work list. Instead, it is added as late as possible manually here. 920 append_block(osr_entry); 921 compute_dominator(cur, osr_entry); 922 } 923 append_block(cur); 924 925 int i; 926 int num_sux = cur->number_of_sux(); 927 // changed loop order to get "intuitive" order of if- and else-blocks 928 for (i = 0; i < num_sux; i++) { 929 BlockBegin* sux = cur->sux_at(i); 930 compute_dominator(sux, cur); 931 if (ready_for_processing(sux)) { 932 sort_into_work_list(sux); 933 } 934 } 935 num_sux = cur->number_of_exception_handlers(); 936 for (i = 0; i < num_sux; i++) { 937 BlockBegin* sux = cur->exception_handler_at(i); 938 compute_dominator(sux, cur); 939 if (ready_for_processing(sux)) { 940 sort_into_work_list(sux); 941 } 942 } 943 } while (_work_list.length() > 0); 944 } 945 946 947 bool ComputeLinearScanOrder::compute_dominators_iter() { 948 bool changed = false; 949 int num_blocks = _linear_scan_order->length(); 950 951 assert(_linear_scan_order->at(0)->dominator() == NULL, "must not have dominator"); 952 assert(_linear_scan_order->at(0)->number_of_preds() == 0, "must not have predecessors"); 953 for (int i = 1; i < num_blocks; i++) { 954 BlockBegin* block = _linear_scan_order->at(i); 955 956 BlockBegin* dominator = block->pred_at(0); 957 int num_preds = block->number_of_preds(); 958 for (int i = 1; i < num_preds; i++) { 959 dominator = common_dominator(dominator, block->pred_at(i)); 960 } 961 962 if (dominator != block->dominator()) { 963 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: updating dominator of B%d from B%d to B%d", block->block_id(), block->dominator()->block_id(), dominator->block_id())); 964 965 block->set_dominator(dominator); 966 changed = true; 967 } 968 } 969 return changed; 970 } 971 972 void ComputeLinearScanOrder::compute_dominators() { 973 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing dominators (iterative computation reqired: %d)", _iterative_dominators)); 974 975 // iterative computation of dominators is only required for methods with non-natural loops 976 // and OSR-methods. For all other methods, the dominators computed when generating the 977 // linear scan block order are correct. 978 if (_iterative_dominators) { 979 do { 980 TRACE_LINEAR_SCAN(1, tty->print_cr("DOM: next iteration of fix-point calculation")); 981 } while (compute_dominators_iter()); 982 } 983 984 // check that dominators are correct 985 assert(!compute_dominators_iter(), "fix point not reached"); 986 } 987 988 989 #ifndef PRODUCT 990 void ComputeLinearScanOrder::print_blocks() { 991 if (TraceLinearScanLevel >= 2) { 992 tty->print_cr("----- loop information:"); 993 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { 994 BlockBegin* cur = _linear_scan_order->at(block_idx); 995 996 tty->print("%4d: B%2d: ", cur->linear_scan_number(), cur->block_id()); 997 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { 998 tty->print ("%d ", is_block_in_loop(loop_idx, cur)); 999 } 1000 tty->print_cr(" -> loop_index: %2d, loop_depth: %2d", cur->loop_index(), cur->loop_depth()); 1001 } 1002 } 1003 1004 if (TraceLinearScanLevel >= 1) { 1005 tty->print_cr("----- linear-scan block order:"); 1006 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { 1007 BlockBegin* cur = _linear_scan_order->at(block_idx); 1008 tty->print("%4d: B%2d loop: %2d depth: %2d", cur->linear_scan_number(), cur->block_id(), cur->loop_index(), cur->loop_depth()); 1009 1010 tty->print(cur->is_set(BlockBegin::exception_entry_flag) ? " ex" : " "); 1011 tty->print(cur->is_set(BlockBegin::critical_edge_split_flag) ? " ce" : " "); 1012 tty->print(cur->is_set(BlockBegin::linear_scan_loop_header_flag) ? " lh" : " "); 1013 tty->print(cur->is_set(BlockBegin::linear_scan_loop_end_flag) ? " le" : " "); 1014 1015 if (cur->dominator() != NULL) { 1016 tty->print(" dom: B%d ", cur->dominator()->block_id()); 1017 } else { 1018 tty->print(" dom: NULL "); 1019 } 1020 1021 if (cur->number_of_preds() > 0) { 1022 tty->print(" preds: "); 1023 for (int j = 0; j < cur->number_of_preds(); j++) { 1024 BlockBegin* pred = cur->pred_at(j); 1025 tty->print("B%d ", pred->block_id()); 1026 } 1027 } 1028 if (cur->number_of_sux() > 0) { 1029 tty->print(" sux: "); 1030 for (int j = 0; j < cur->number_of_sux(); j++) { 1031 BlockBegin* sux = cur->sux_at(j); 1032 tty->print("B%d ", sux->block_id()); 1033 } 1034 } 1035 if (cur->number_of_exception_handlers() > 0) { 1036 tty->print(" ex: "); 1037 for (int j = 0; j < cur->number_of_exception_handlers(); j++) { 1038 BlockBegin* ex = cur->exception_handler_at(j); 1039 tty->print("B%d ", ex->block_id()); 1040 } 1041 } 1042 tty->cr(); 1043 } 1044 } 1045 } 1046 #endif 1047 1048 #ifdef ASSERT 1049 void ComputeLinearScanOrder::verify() { 1050 assert(_linear_scan_order->length() == _num_blocks, "wrong number of blocks in list"); 1051 1052 if (StressLinearScan) { 1053 // blocks are scrambled when StressLinearScan is used 1054 return; 1055 } 1056 1057 // check that all successors of a block have a higher linear-scan-number 1058 // and that all predecessors of a block have a lower linear-scan-number 1059 // (only backward branches of loops are ignored) 1060 int i; 1061 for (i = 0; i < _linear_scan_order->length(); i++) { 1062 BlockBegin* cur = _linear_scan_order->at(i); 1063 1064 assert(cur->linear_scan_number() == i, "incorrect linear_scan_number"); 1065 assert(cur->linear_scan_number() >= 0 && cur->linear_scan_number() == _linear_scan_order->index_of(cur), "incorrect linear_scan_number"); 1066 1067 int j; 1068 for (j = cur->number_of_sux() - 1; j >= 0; j--) { 1069 BlockBegin* sux = cur->sux_at(j); 1070 1071 assert(sux->linear_scan_number() >= 0 && sux->linear_scan_number() == _linear_scan_order->index_of(sux), "incorrect linear_scan_number"); 1072 if (!cur->is_set(BlockBegin::linear_scan_loop_end_flag)) { 1073 assert(cur->linear_scan_number() < sux->linear_scan_number(), "invalid order"); 1074 } 1075 if (cur->loop_depth() == sux->loop_depth()) { 1076 assert(cur->loop_index() == sux->loop_index() || sux->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index"); 1077 } 1078 } 1079 1080 for (j = cur->number_of_preds() - 1; j >= 0; j--) { 1081 BlockBegin* pred = cur->pred_at(j); 1082 1083 assert(pred->linear_scan_number() >= 0 && pred->linear_scan_number() == _linear_scan_order->index_of(pred), "incorrect linear_scan_number"); 1084 if (!cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { 1085 assert(cur->linear_scan_number() > pred->linear_scan_number(), "invalid order"); 1086 } 1087 if (cur->loop_depth() == pred->loop_depth()) { 1088 assert(cur->loop_index() == pred->loop_index() || cur->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index"); 1089 } 1090 1091 assert(cur->dominator()->linear_scan_number() <= cur->pred_at(j)->linear_scan_number(), "dominator must be before predecessors"); 1092 } 1093 1094 // check dominator 1095 if (i == 0) { 1096 assert(cur->dominator() == NULL, "first block has no dominator"); 1097 } else { 1098 assert(cur->dominator() != NULL, "all but first block must have dominator"); 1099 } 1100 assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0), "Single predecessor must also be dominator"); 1101 } 1102 1103 // check that all loops are continuous 1104 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { 1105 int block_idx = 0; 1106 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "the first block must not be present in any loop"); 1107 1108 // skip blocks before the loop 1109 while (block_idx < _num_blocks && !is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { 1110 block_idx++; 1111 } 1112 // skip blocks of loop 1113 while (block_idx < _num_blocks && is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { 1114 block_idx++; 1115 } 1116 // after the first non-loop block, there must not be another loop-block 1117 while (block_idx < _num_blocks) { 1118 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "loop not continuous in linear-scan order"); 1119 block_idx++; 1120 } 1121 } 1122 } 1123 #endif 1124 1125 1126 void IR::compute_code() { 1127 assert(is_valid(), "IR must be valid"); 1128 1129 ComputeLinearScanOrder compute_order(start()); 1130 _num_loops = compute_order.num_loops(); 1131 _code = compute_order.linear_scan_order(); 1132 } 1133 1134 1135 void IR::compute_use_counts() { 1136 // make sure all values coming out of this block get evaluated. 1137 int num_blocks = _code->length(); 1138 for (int i = 0; i < num_blocks; i++) { 1139 _code->at(i)->end()->state()->pin_stack_for_linear_scan(); 1140 } 1141 1142 // compute use counts 1143 UseCountComputer::compute(_code); 1144 } 1145 1146 1147 void IR::iterate_preorder(BlockClosure* closure) { 1148 assert(is_valid(), "IR must be valid"); 1149 start()->iterate_preorder(closure); 1150 } 1151 1152 1153 void IR::iterate_postorder(BlockClosure* closure) { 1154 assert(is_valid(), "IR must be valid"); 1155 start()->iterate_postorder(closure); 1156 } 1157 1158 void IR::iterate_linear_scan_order(BlockClosure* closure) { 1159 linear_scan_order()->iterate_forward(closure); 1160 } 1161 1162 1163 #ifndef PRODUCT 1164 class BlockPrinter: public BlockClosure { 1165 private: 1166 InstructionPrinter* _ip; 1167 bool _cfg_only; 1168 bool _live_only; 1169 1170 public: 1171 BlockPrinter(InstructionPrinter* ip, bool cfg_only, bool live_only = false) { 1172 _ip = ip; 1173 _cfg_only = cfg_only; 1174 _live_only = live_only; 1175 } 1176 1177 virtual void block_do(BlockBegin* block) { 1178 if (_cfg_only) { 1179 _ip->print_instr(block); tty->cr(); 1180 } else { 1181 block->print_block(*_ip, _live_only); 1182 } 1183 } 1184 }; 1185 1186 1187 void IR::print(BlockBegin* start, bool cfg_only, bool live_only) { 1188 ttyLocker ttyl; 1189 InstructionPrinter ip(!cfg_only); 1190 BlockPrinter bp(&ip, cfg_only, live_only); 1191 start->iterate_preorder(&bp); 1192 tty->cr(); 1193 } 1194 1195 void IR::print(bool cfg_only, bool live_only) { 1196 if (is_valid()) { 1197 print(start(), cfg_only, live_only); 1198 } else { 1199 tty->print_cr("invalid IR"); 1200 } 1201 } 1202 1203 1204 define_array(BlockListArray, BlockList*) 1205 define_stack(BlockListList, BlockListArray) 1206 1207 class PredecessorValidator : public BlockClosure { 1208 private: 1209 BlockListList* _predecessors; 1210 BlockList* _blocks; 1211 1212 static int cmp(BlockBegin** a, BlockBegin** b) { 1213 return (*a)->block_id() - (*b)->block_id(); 1214 } 1215 1216 public: 1217 PredecessorValidator(IR* hir) { 1218 ResourceMark rm; 1219 _predecessors = new BlockListList(BlockBegin::number_of_blocks(), NULL); 1220 _blocks = new BlockList(); 1221 1222 int i; 1223 hir->start()->iterate_preorder(this); 1224 if (hir->code() != NULL) { 1225 assert(hir->code()->length() == _blocks->length(), "must match"); 1226 for (i = 0; i < _blocks->length(); i++) { 1227 assert(hir->code()->contains(_blocks->at(i)), "should be in both lists"); 1228 } 1229 } 1230 1231 for (i = 0; i < _blocks->length(); i++) { 1232 BlockBegin* block = _blocks->at(i); 1233 BlockList* preds = _predecessors->at(block->block_id()); 1234 if (preds == NULL) { 1235 assert(block->number_of_preds() == 0, "should be the same"); 1236 continue; 1237 } 1238 1239 // clone the pred list so we can mutate it 1240 BlockList* pred_copy = new BlockList(); 1241 int j; 1242 for (j = 0; j < block->number_of_preds(); j++) { 1243 pred_copy->append(block->pred_at(j)); 1244 } 1245 // sort them in the same order 1246 preds->sort(cmp); 1247 pred_copy->sort(cmp); 1248 int length = MIN2(preds->length(), block->number_of_preds()); 1249 for (j = 0; j < block->number_of_preds(); j++) { 1250 assert(preds->at(j) == pred_copy->at(j), "must match"); 1251 } 1252 1253 assert(preds->length() == block->number_of_preds(), "should be the same"); 1254 } 1255 } 1256 1257 virtual void block_do(BlockBegin* block) { 1258 _blocks->append(block); 1259 BlockEnd* be = block->end(); 1260 int n = be->number_of_sux(); 1261 int i; 1262 for (i = 0; i < n; i++) { 1263 BlockBegin* sux = be->sux_at(i); 1264 assert(!sux->is_set(BlockBegin::exception_entry_flag), "must not be xhandler"); 1265 1266 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); 1267 if (preds == NULL) { 1268 preds = new BlockList(); 1269 _predecessors->at_put(sux->block_id(), preds); 1270 } 1271 preds->append(block); 1272 } 1273 1274 n = block->number_of_exception_handlers(); 1275 for (i = 0; i < n; i++) { 1276 BlockBegin* sux = block->exception_handler_at(i); 1277 assert(sux->is_set(BlockBegin::exception_entry_flag), "must be xhandler"); 1278 1279 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); 1280 if (preds == NULL) { 1281 preds = new BlockList(); 1282 _predecessors->at_put(sux->block_id(), preds); 1283 } 1284 preds->append(block); 1285 } 1286 } 1287 }; 1288 1289 void IR::verify() { 1290 #ifdef ASSERT 1291 PredecessorValidator pv(this); 1292 #endif 1293 } 1294 1295 #endif // PRODUCT 1296 1297 void SubstitutionResolver::substitute(Value* v) { 1298 Value v0 = *v; 1299 if (v0) { 1300 Value vs = v0->subst(); 1301 if (vs != v0) { 1302 *v = v0->subst(); 1303 } 1304 } 1305 } 1306 1307 #ifdef ASSERT 1308 void check_substitute(Value* v) { 1309 Value v0 = *v; 1310 if (v0) { 1311 Value vs = v0->subst(); 1312 assert(vs == v0, "missed substitution"); 1313 } 1314 } 1315 #endif 1316 1317 1318 void SubstitutionResolver::block_do(BlockBegin* block) { 1319 Instruction* last = NULL; 1320 for (Instruction* n = block; n != NULL;) { 1321 n->values_do(substitute); 1322 // need to remove this instruction from the instruction stream 1323 if (n->subst() != n) { 1324 assert(last != NULL, "must have last"); 1325 last->set_next(n->next(), n->next()->bci()); 1326 } else { 1327 last = n; 1328 } 1329 n = last->next(); 1330 } 1331 1332 #ifdef ASSERT 1333 if (block->state()) block->state()->values_do(check_substitute); 1334 block->block_values_do(check_substitute); 1335 if (block->end() && block->end()->state()) block->end()->state()->values_do(check_substitute); 1336 #endif 1337 }