c1_IR.cpp revision 1472:c18cbe5936b8
1/* 2 * Copyright (c) 1999, 2010, 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 "incls/_precompiled.incl" 26# include "incls/_c1_IR.cpp.incl" 27 28 29// Implementation of XHandlers 30// 31// Note: This code could eventually go away if we are 32// just using the ciExceptionHandlerStream. 33 34XHandlers::XHandlers(ciMethod* method) : _list(method->exception_table_length()) { 35 ciExceptionHandlerStream s(method); 36 while (!s.is_done()) { 37 _list.append(new XHandler(s.handler())); 38 s.next(); 39 } 40 assert(s.count() == method->exception_table_length(), "exception table lengths inconsistent"); 41} 42 43// deep copy of all XHandler contained in list 44XHandlers::XHandlers(XHandlers* other) : 45 _list(other->length()) 46{ 47 for (int i = 0; i < other->length(); i++) { 48 _list.append(new XHandler(other->handler_at(i))); 49 } 50} 51 52// Returns whether a particular exception type can be caught. Also 53// returns true if klass is unloaded or any exception handler 54// classes are unloaded. type_is_exact indicates whether the throw 55// is known to be exactly that class or it might throw a subtype. 56bool XHandlers::could_catch(ciInstanceKlass* klass, bool type_is_exact) const { 57 // the type is unknown so be conservative 58 if (!klass->is_loaded()) { 59 return true; 60 } 61 62 for (int i = 0; i < length(); i++) { 63 XHandler* handler = handler_at(i); 64 if (handler->is_catch_all()) { 65 // catch of ANY 66 return true; 67 } 68 ciInstanceKlass* handler_klass = handler->catch_klass(); 69 // if it's unknown it might be catchable 70 if (!handler_klass->is_loaded()) { 71 return true; 72 } 73 // if the throw type is definitely a subtype of the catch type 74 // then it can be caught. 75 if (klass->is_subtype_of(handler_klass)) { 76 return true; 77 } 78 if (!type_is_exact) { 79 // If the type isn't exactly known then it can also be caught by 80 // catch statements where the inexact type is a subtype of the 81 // catch type. 82 // given: foo extends bar extends Exception 83 // throw bar can be caught by catch foo, catch bar, and catch 84 // Exception, however it can't be caught by any handlers without 85 // bar in its type hierarchy. 86 if (handler_klass->is_subtype_of(klass)) { 87 return true; 88 } 89 } 90 } 91 92 return false; 93} 94 95 96bool XHandlers::equals(XHandlers* others) const { 97 if (others == NULL) return false; 98 if (length() != others->length()) return false; 99 100 for (int i = 0; i < length(); i++) { 101 if (!handler_at(i)->equals(others->handler_at(i))) return false; 102 } 103 return true; 104} 105 106bool XHandler::equals(XHandler* other) const { 107 assert(entry_pco() != -1 && other->entry_pco() != -1, "must have entry_pco"); 108 109 if (entry_pco() != other->entry_pco()) return false; 110 if (scope_count() != other->scope_count()) return false; 111 if (_desc != other->_desc) return false; 112 113 assert(entry_block() == other->entry_block(), "entry_block must be equal when entry_pco is equal"); 114 return true; 115} 116 117 118// Implementation of IRScope 119 120BlockBegin* IRScope::header_block(BlockBegin* entry, BlockBegin::Flag f, ValueStack* state) { 121 if (entry == NULL) return NULL; 122 assert(entry->is_set(f), "entry/flag mismatch"); 123 // create header block 124 BlockBegin* h = new BlockBegin(entry->bci()); 125 BlockEnd* g = new Goto(entry, false); 126 h->set_next(g, entry->bci()); 127 h->set_end(g); 128 h->set(f); 129 // setup header block end state 130 ValueStack* s = state->copy(); // can use copy since stack is empty (=> no phis) 131 assert(s->stack_is_empty(), "must have empty stack at entry point"); 132 g->set_state(s); 133 return h; 134} 135 136 137BlockBegin* IRScope::build_graph(Compilation* compilation, int osr_bci) { 138 GraphBuilder gm(compilation, this); 139 NOT_PRODUCT(if (PrintValueNumbering && Verbose) gm.print_stats()); 140 if (compilation->bailed_out()) return NULL; 141 return gm.start(); 142} 143 144 145IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMethod* method, int osr_bci, bool create_graph) 146: _callees(2) 147, _compilation(compilation) 148, _lock_stack_size(-1) 149, _requires_phi_function(method->max_locals()) 150{ 151 _caller = caller; 152 _caller_bci = caller == NULL ? -1 : caller_bci; 153 _caller_state = NULL; // Must be set later if needed 154 _level = caller == NULL ? 0 : caller->level() + 1; 155 _method = method; 156 _xhandlers = new XHandlers(method); 157 _number_of_locks = 0; 158 _monitor_pairing_ok = method->has_balanced_monitors(); 159 _start = NULL; 160 161 if (osr_bci == -1) { 162 _requires_phi_function.clear(); 163 } else { 164 // selective creation of phi functions is not possibel in osr-methods 165 _requires_phi_function.set_range(0, method->max_locals()); 166 } 167 168 assert(method->holder()->is_loaded() , "method holder must be loaded"); 169 170 // build graph if monitor pairing is ok 171 if (create_graph && monitor_pairing_ok()) _start = build_graph(compilation, osr_bci); 172} 173 174 175int IRScope::max_stack() const { 176 int my_max = method()->max_stack(); 177 int callee_max = 0; 178 for (int i = 0; i < number_of_callees(); i++) { 179 callee_max = MAX2(callee_max, callee_no(i)->max_stack()); 180 } 181 return my_max + callee_max; 182} 183 184 185void IRScope::compute_lock_stack_size() { 186 if (!InlineMethodsWithExceptionHandlers) { 187 _lock_stack_size = 0; 188 return; 189 } 190 191 // Figure out whether we have to preserve expression stack elements 192 // for parent scopes, and if so, how many 193 IRScope* cur_scope = this; 194 while (cur_scope != NULL && !cur_scope->xhandlers()->has_handlers()) { 195 cur_scope = cur_scope->caller(); 196 } 197 _lock_stack_size = (cur_scope == NULL ? 0 : 198 (cur_scope->caller_state() == NULL ? 0 : 199 cur_scope->caller_state()->stack_size())); 200} 201 202int IRScope::top_scope_bci() const { 203 assert(!is_top_scope(), "no correct answer for top scope possible"); 204 const IRScope* scope = this; 205 while (!scope->caller()->is_top_scope()) { 206 scope = scope->caller(); 207 } 208 return scope->caller_bci(); 209} 210 211bool IRScopeDebugInfo::should_reexecute() { 212 ciMethod* cur_method = scope()->method(); 213 int cur_bci = bci(); 214 if (cur_method != NULL && cur_bci != SynchronizationEntryBCI) { 215 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci); 216 return Interpreter::bytecode_should_reexecute(code); 217 } else 218 return false; 219} 220 221 222// Implementation of CodeEmitInfo 223 224// Stack must be NON-null 225CodeEmitInfo::CodeEmitInfo(int bci, ValueStack* stack, XHandlers* exception_handlers) 226 : _scope(stack->scope()) 227 , _bci(bci) 228 , _scope_debug_info(NULL) 229 , _oop_map(NULL) 230 , _stack(stack) 231 , _exception_handlers(exception_handlers) 232 , _next(NULL) 233 , _id(-1) { 234 assert(_stack != NULL, "must be non null"); 235 assert(_bci == SynchronizationEntryBCI || Bytecodes::is_defined(scope()->method()->java_code_at_bci(_bci)), "make sure bci points at a real bytecode"); 236} 237 238 239CodeEmitInfo::CodeEmitInfo(CodeEmitInfo* info, bool lock_stack_only) 240 : _scope(info->_scope) 241 , _exception_handlers(NULL) 242 , _bci(info->_bci) 243 , _scope_debug_info(NULL) 244 , _oop_map(NULL) { 245 if (lock_stack_only) { 246 if (info->_stack != NULL) { 247 _stack = info->_stack->copy_locks(); 248 } else { 249 _stack = NULL; 250 } 251 } else { 252 _stack = info->_stack; 253 } 254 255 // deep copy of exception handlers 256 if (info->_exception_handlers != NULL) { 257 _exception_handlers = new XHandlers(info->_exception_handlers); 258 } 259} 260 261 262void CodeEmitInfo::record_debug_info(DebugInformationRecorder* recorder, int pc_offset, bool is_method_handle_invoke) { 263 // record the safepoint before recording the debug info for enclosing scopes 264 recorder->add_safepoint(pc_offset, _oop_map->deep_copy()); 265 _scope_debug_info->record_debug_info(recorder, pc_offset, true/*topmost*/, is_method_handle_invoke); 266 recorder->end_safepoint(pc_offset); 267} 268 269 270void CodeEmitInfo::add_register_oop(LIR_Opr opr) { 271 assert(_oop_map != NULL, "oop map must already exist"); 272 assert(opr->is_single_cpu(), "should not call otherwise"); 273 274 int frame_size = frame_map()->framesize(); 275 int arg_count = frame_map()->oop_map_arg_count(); 276 VMReg name = frame_map()->regname(opr); 277 _oop_map->set_oop(name); 278} 279 280 281 282 283// Implementation of IR 284 285IR::IR(Compilation* compilation, ciMethod* method, int osr_bci) : 286 _locals_size(in_WordSize(-1)) 287 , _num_loops(0) { 288 // initialize data structures 289 ValueType::initialize(); 290 Instruction::initialize(); 291 BlockBegin::initialize(); 292 GraphBuilder::initialize(); 293 // setup IR fields 294 _compilation = compilation; 295 _top_scope = new IRScope(compilation, NULL, -1, method, osr_bci, true); 296 _code = NULL; 297} 298 299 300void IR::optimize() { 301 Optimizer opt(this); 302 if (DoCEE) { 303 opt.eliminate_conditional_expressions(); 304#ifndef PRODUCT 305 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after CEE"); print(true); } 306 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after CEE"); print(false); } 307#endif 308 } 309 if (EliminateBlocks) { 310 opt.eliminate_blocks(); 311#ifndef PRODUCT 312 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after block elimination"); print(true); } 313 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after block elimination"); print(false); } 314#endif 315 } 316 if (EliminateNullChecks) { 317 opt.eliminate_null_checks(); 318#ifndef PRODUCT 319 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after null check elimination"); print(true); } 320 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after null check elimination"); print(false); } 321#endif 322 } 323} 324 325 326static int sort_pairs(BlockPair** a, BlockPair** b) { 327 if ((*a)->from() == (*b)->from()) { 328 return (*a)->to()->block_id() - (*b)->to()->block_id(); 329 } else { 330 return (*a)->from()->block_id() - (*b)->from()->block_id(); 331 } 332} 333 334 335class CriticalEdgeFinder: public BlockClosure { 336 BlockPairList blocks; 337 IR* _ir; 338 339 public: 340 CriticalEdgeFinder(IR* ir): _ir(ir) {} 341 void block_do(BlockBegin* bb) { 342 BlockEnd* be = bb->end(); 343 int nos = be->number_of_sux(); 344 if (nos >= 2) { 345 for (int i = 0; i < nos; i++) { 346 BlockBegin* sux = be->sux_at(i); 347 if (sux->number_of_preds() >= 2) { 348 blocks.append(new BlockPair(bb, sux)); 349 } 350 } 351 } 352 } 353 354 void split_edges() { 355 BlockPair* last_pair = NULL; 356 blocks.sort(sort_pairs); 357 for (int i = 0; i < blocks.length(); i++) { 358 BlockPair* pair = blocks.at(i); 359 if (last_pair != NULL && pair->is_same(last_pair)) continue; 360 BlockBegin* from = pair->from(); 361 BlockBegin* to = pair->to(); 362 BlockBegin* split = from->insert_block_between(to); 363#ifndef PRODUCT 364 if ((PrintIR || PrintIR1) && Verbose) { 365 tty->print_cr("Split critical edge B%d -> B%d (new block B%d)", 366 from->block_id(), to->block_id(), split->block_id()); 367 } 368#endif 369 last_pair = pair; 370 } 371 } 372}; 373 374void IR::split_critical_edges() { 375 CriticalEdgeFinder cef(this); 376 377 iterate_preorder(&cef); 378 cef.split_edges(); 379} 380 381 382class UseCountComputer: public AllStatic { 383 private: 384 static void update_use_count(Value* n) { 385 // Local instructions and Phis for expression stack values at the 386 // start of basic blocks are not added to the instruction list 387 if ((*n)->bci() == -99 && (*n)->as_Local() == NULL && 388 (*n)->as_Phi() == NULL) { 389 assert(false, "a node was not appended to the graph"); 390 Compilation::current_compilation()->bailout("a node was not appended to the graph"); 391 } 392 // use n's input if not visited before 393 if (!(*n)->is_pinned() && !(*n)->has_uses()) { 394 // note: a) if the instruction is pinned, it will be handled by compute_use_count 395 // b) if the instruction has uses, it was touched before 396 // => in both cases we don't need to update n's values 397 uses_do(n); 398 } 399 // use n 400 (*n)->_use_count++; 401 } 402 403 static Values* worklist; 404 static int depth; 405 enum { 406 max_recurse_depth = 20 407 }; 408 409 static void uses_do(Value* n) { 410 depth++; 411 if (depth > max_recurse_depth) { 412 // don't allow the traversal to recurse too deeply 413 worklist->push(*n); 414 } else { 415 (*n)->input_values_do(update_use_count); 416 // special handling for some instructions 417 if ((*n)->as_BlockEnd() != NULL) { 418 // note on BlockEnd: 419 // must 'use' the stack only if the method doesn't 420 // terminate, however, in those cases stack is empty 421 (*n)->state_values_do(update_use_count); 422 } 423 } 424 depth--; 425 } 426 427 static void basic_compute_use_count(BlockBegin* b) { 428 depth = 0; 429 // process all pinned nodes as the roots of expression trees 430 for (Instruction* n = b; n != NULL; n = n->next()) { 431 if (n->is_pinned()) uses_do(&n); 432 } 433 assert(depth == 0, "should have counted back down"); 434 435 // now process any unpinned nodes which recursed too deeply 436 while (worklist->length() > 0) { 437 Value t = worklist->pop(); 438 if (!t->is_pinned()) { 439 // compute the use count 440 uses_do(&t); 441 442 // pin the instruction so that LIRGenerator doesn't recurse 443 // too deeply during it's evaluation. 444 t->pin(); 445 } 446 } 447 assert(depth == 0, "should have counted back down"); 448 } 449 450 public: 451 static void compute(BlockList* blocks) { 452 worklist = new Values(); 453 blocks->blocks_do(basic_compute_use_count); 454 worklist = NULL; 455 } 456}; 457 458 459Values* UseCountComputer::worklist = NULL; 460int UseCountComputer::depth = 0; 461 462// helper macro for short definition of trace-output inside code 463#ifndef PRODUCT 464 #define TRACE_LINEAR_SCAN(level, code) \ 465 if (TraceLinearScanLevel >= level) { \ 466 code; \ 467 } 468#else 469 #define TRACE_LINEAR_SCAN(level, code) 470#endif 471 472class ComputeLinearScanOrder : public StackObj { 473 private: 474 int _max_block_id; // the highest block_id of a block 475 int _num_blocks; // total number of blocks (smaller than _max_block_id) 476 int _num_loops; // total number of loops 477 bool _iterative_dominators;// method requires iterative computation of dominatiors 478 479 BlockList* _linear_scan_order; // the resulting list of blocks in correct order 480 481 BitMap _visited_blocks; // used for recursive processing of blocks 482 BitMap _active_blocks; // used for recursive processing of blocks 483 BitMap _dominator_blocks; // temproary BitMap used for computation of dominator 484 intArray _forward_branches; // number of incoming forward branches for each block 485 BlockList _loop_end_blocks; // list of all loop end blocks collected during count_edges 486 BitMap2D _loop_map; // two-dimensional bit set: a bit is set if a block is contained in a loop 487 BlockList _work_list; // temporary list (used in mark_loops and compute_order) 488 489 // accessors for _visited_blocks and _active_blocks 490 void init_visited() { _active_blocks.clear(); _visited_blocks.clear(); } 491 bool is_visited(BlockBegin* b) const { return _visited_blocks.at(b->block_id()); } 492 bool is_active(BlockBegin* b) const { return _active_blocks.at(b->block_id()); } 493 void set_visited(BlockBegin* b) { assert(!is_visited(b), "already set"); _visited_blocks.set_bit(b->block_id()); } 494 void set_active(BlockBegin* b) { assert(!is_active(b), "already set"); _active_blocks.set_bit(b->block_id()); } 495 void clear_active(BlockBegin* b) { assert(is_active(b), "not already"); _active_blocks.clear_bit(b->block_id()); } 496 497 // accessors for _forward_branches 498 void inc_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) + 1); } 499 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()); } 500 501 // accessors for _loop_map 502 bool is_block_in_loop (int loop_idx, BlockBegin* b) const { return _loop_map.at(loop_idx, b->block_id()); } 503 void set_block_in_loop (int loop_idx, BlockBegin* b) { _loop_map.set_bit(loop_idx, b->block_id()); } 504 void clear_block_in_loop(int loop_idx, int block_id) { _loop_map.clear_bit(loop_idx, block_id); } 505 506 // count edges between blocks 507 void count_edges(BlockBegin* cur, BlockBegin* parent); 508 509 // loop detection 510 void mark_loops(); 511 void clear_non_natural_loops(BlockBegin* start_block); 512 void assign_loop_depth(BlockBegin* start_block); 513 514 // computation of final block order 515 BlockBegin* common_dominator(BlockBegin* a, BlockBegin* b); 516 void compute_dominator(BlockBegin* cur, BlockBegin* parent); 517 int compute_weight(BlockBegin* cur); 518 bool ready_for_processing(BlockBegin* cur); 519 void sort_into_work_list(BlockBegin* b); 520 void append_block(BlockBegin* cur); 521 void compute_order(BlockBegin* start_block); 522 523 // fixup of dominators for non-natural loops 524 bool compute_dominators_iter(); 525 void compute_dominators(); 526 527 // debug functions 528 NOT_PRODUCT(void print_blocks();) 529 DEBUG_ONLY(void verify();) 530 531 public: 532 ComputeLinearScanOrder(BlockBegin* start_block); 533 534 // accessors for final result 535 BlockList* linear_scan_order() const { return _linear_scan_order; } 536 int num_loops() const { return _num_loops; } 537}; 538 539 540ComputeLinearScanOrder::ComputeLinearScanOrder(BlockBegin* start_block) : 541 _max_block_id(BlockBegin::number_of_blocks()), 542 _num_blocks(0), 543 _num_loops(0), 544 _iterative_dominators(false), 545 _visited_blocks(_max_block_id), 546 _active_blocks(_max_block_id), 547 _dominator_blocks(_max_block_id), 548 _forward_branches(_max_block_id, 0), 549 _loop_end_blocks(8), 550 _work_list(8), 551 _linear_scan_order(NULL), // initialized later with correct size 552 _loop_map(0, 0) // initialized later with correct size 553{ 554 TRACE_LINEAR_SCAN(2, "***** computing linear-scan block order"); 555 556 init_visited(); 557 count_edges(start_block, NULL); 558 559 if (_num_loops > 0) { 560 mark_loops(); 561 clear_non_natural_loops(start_block); 562 assign_loop_depth(start_block); 563 } 564 565 compute_order(start_block); 566 compute_dominators(); 567 568 NOT_PRODUCT(print_blocks()); 569 DEBUG_ONLY(verify()); 570} 571 572 573// Traverse the CFG: 574// * count total number of blocks 575// * count all incoming edges and backward incoming edges 576// * number loop header blocks 577// * create a list with all loop end blocks 578void ComputeLinearScanOrder::count_edges(BlockBegin* cur, BlockBegin* parent) { 579 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)); 580 assert(cur->dominator() == NULL, "dominator already initialized"); 581 582 if (is_active(cur)) { 583 TRACE_LINEAR_SCAN(3, tty->print_cr("backward branch")); 584 assert(is_visited(cur), "block must be visisted when block is active"); 585 assert(parent != NULL, "must have parent"); 586 587 cur->set(BlockBegin::linear_scan_loop_header_flag); 588 cur->set(BlockBegin::backward_branch_target_flag); 589 590 parent->set(BlockBegin::linear_scan_loop_end_flag); 591 592 // When a loop header is also the start of an exception handler, then the backward branch is 593 // an exception edge. Because such edges are usually critical edges which cannot be split, the 594 // loop must be excluded here from processing. 595 if (cur->is_set(BlockBegin::exception_entry_flag)) { 596 // Make sure that dominators are correct in this weird situation 597 _iterative_dominators = true; 598 return; 599 } 600 assert(parent->number_of_sux() == 1 && parent->sux_at(0) == cur, 601 "loop end blocks must have one successor (critical edges are split)"); 602 603 _loop_end_blocks.append(parent); 604 return; 605 } 606 607 // increment number of incoming forward branches 608 inc_forward_branches(cur); 609 610 if (is_visited(cur)) { 611 TRACE_LINEAR_SCAN(3, tty->print_cr("block already visited")); 612 return; 613 } 614 615 _num_blocks++; 616 set_visited(cur); 617 set_active(cur); 618 619 // recursive call for all successors 620 int i; 621 for (i = cur->number_of_sux() - 1; i >= 0; i--) { 622 count_edges(cur->sux_at(i), cur); 623 } 624 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { 625 count_edges(cur->exception_handler_at(i), cur); 626 } 627 628 clear_active(cur); 629 630 // Each loop has a unique number. 631 // When multiple loops are nested, assign_loop_depth assumes that the 632 // innermost loop has the lowest number. This is guaranteed by setting 633 // the loop number after the recursive calls for the successors above 634 // have returned. 635 if (cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { 636 assert(cur->loop_index() == -1, "cannot set loop-index twice"); 637 TRACE_LINEAR_SCAN(3, tty->print_cr("Block B%d is loop header of loop %d", cur->block_id(), _num_loops)); 638 639 cur->set_loop_index(_num_loops); 640 _num_loops++; 641 } 642 643 TRACE_LINEAR_SCAN(3, tty->print_cr("Finished count_edges for block B%d", cur->block_id())); 644} 645 646 647void ComputeLinearScanOrder::mark_loops() { 648 TRACE_LINEAR_SCAN(3, tty->print_cr("----- marking loops")); 649 650 _loop_map = BitMap2D(_num_loops, _max_block_id); 651 _loop_map.clear(); 652 653 for (int i = _loop_end_blocks.length() - 1; i >= 0; i--) { 654 BlockBegin* loop_end = _loop_end_blocks.at(i); 655 BlockBegin* loop_start = loop_end->sux_at(0); 656 int loop_idx = loop_start->loop_index(); 657 658 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)); 659 assert(loop_end->is_set(BlockBegin::linear_scan_loop_end_flag), "loop end flag must be set"); 660 assert(loop_end->number_of_sux() == 1, "incorrect number of successors"); 661 assert(loop_start->is_set(BlockBegin::linear_scan_loop_header_flag), "loop header flag must be set"); 662 assert(loop_idx >= 0 && loop_idx < _num_loops, "loop index not set"); 663 assert(_work_list.is_empty(), "work list must be empty before processing"); 664 665 // add the end-block of the loop to the working list 666 _work_list.push(loop_end); 667 set_block_in_loop(loop_idx, loop_end); 668 do { 669 BlockBegin* cur = _work_list.pop(); 670 671 TRACE_LINEAR_SCAN(3, tty->print_cr(" processing B%d", cur->block_id())); 672 assert(is_block_in_loop(loop_idx, cur), "bit in loop map must be set when block is in work list"); 673 674 // recursive processing of all predecessors ends when start block of loop is reached 675 if (cur != loop_start && !cur->is_set(BlockBegin::osr_entry_flag)) { 676 for (int j = cur->number_of_preds() - 1; j >= 0; j--) { 677 BlockBegin* pred = cur->pred_at(j); 678 679 if (!is_block_in_loop(loop_idx, pred) /*&& !pred->is_set(BlockBeginosr_entry_flag)*/) { 680 // this predecessor has not been processed yet, so add it to work list 681 TRACE_LINEAR_SCAN(3, tty->print_cr(" pushing B%d", pred->block_id())); 682 _work_list.push(pred); 683 set_block_in_loop(loop_idx, pred); 684 } 685 } 686 } 687 } while (!_work_list.is_empty()); 688 } 689} 690 691 692// check for non-natural loops (loops where the loop header does not dominate 693// all other loop blocks = loops with mulitple entries). 694// such loops are ignored 695void ComputeLinearScanOrder::clear_non_natural_loops(BlockBegin* start_block) { 696 for (int i = _num_loops - 1; i >= 0; i--) { 697 if (is_block_in_loop(i, start_block)) { 698 // loop i contains the entry block of the method 699 // -> this is not a natural loop, so ignore it 700 TRACE_LINEAR_SCAN(2, tty->print_cr("Loop %d is non-natural, so it is ignored", i)); 701 702 for (int block_id = _max_block_id - 1; block_id >= 0; block_id--) { 703 clear_block_in_loop(i, block_id); 704 } 705 _iterative_dominators = true; 706 } 707 } 708} 709 710void ComputeLinearScanOrder::assign_loop_depth(BlockBegin* start_block) { 711 TRACE_LINEAR_SCAN(3, "----- computing loop-depth and weight"); 712 init_visited(); 713 714 assert(_work_list.is_empty(), "work list must be empty before processing"); 715 _work_list.append(start_block); 716 717 do { 718 BlockBegin* cur = _work_list.pop(); 719 720 if (!is_visited(cur)) { 721 set_visited(cur); 722 TRACE_LINEAR_SCAN(4, tty->print_cr("Computing loop depth for block B%d", cur->block_id())); 723 724 // compute loop-depth and loop-index for the block 725 assert(cur->loop_depth() == 0, "cannot set loop-depth twice"); 726 int i; 727 int loop_depth = 0; 728 int min_loop_idx = -1; 729 for (i = _num_loops - 1; i >= 0; i--) { 730 if (is_block_in_loop(i, cur)) { 731 loop_depth++; 732 min_loop_idx = i; 733 } 734 } 735 cur->set_loop_depth(loop_depth); 736 cur->set_loop_index(min_loop_idx); 737 738 // append all unvisited successors to work list 739 for (i = cur->number_of_sux() - 1; i >= 0; i--) { 740 _work_list.append(cur->sux_at(i)); 741 } 742 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { 743 _work_list.append(cur->exception_handler_at(i)); 744 } 745 } 746 } while (!_work_list.is_empty()); 747} 748 749 750BlockBegin* ComputeLinearScanOrder::common_dominator(BlockBegin* a, BlockBegin* b) { 751 assert(a != NULL && b != NULL, "must have input blocks"); 752 753 _dominator_blocks.clear(); 754 while (a != NULL) { 755 _dominator_blocks.set_bit(a->block_id()); 756 assert(a->dominator() != NULL || a == _linear_scan_order->at(0), "dominator must be initialized"); 757 a = a->dominator(); 758 } 759 while (b != NULL && !_dominator_blocks.at(b->block_id())) { 760 assert(b->dominator() != NULL || b == _linear_scan_order->at(0), "dominator must be initialized"); 761 b = b->dominator(); 762 } 763 764 assert(b != NULL, "could not find dominator"); 765 return b; 766} 767 768void ComputeLinearScanOrder::compute_dominator(BlockBegin* cur, BlockBegin* parent) { 769 if (cur->dominator() == NULL) { 770 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: initializing dominator of B%d to B%d", cur->block_id(), parent->block_id())); 771 cur->set_dominator(parent); 772 773 } else if (!(cur->is_set(BlockBegin::linear_scan_loop_header_flag) && parent->is_set(BlockBegin::linear_scan_loop_end_flag))) { 774 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())); 775 assert(cur->number_of_preds() > 1, ""); 776 cur->set_dominator(common_dominator(cur->dominator(), parent)); 777 } 778} 779 780 781int ComputeLinearScanOrder::compute_weight(BlockBegin* cur) { 782 BlockBegin* single_sux = NULL; 783 if (cur->number_of_sux() == 1) { 784 single_sux = cur->sux_at(0); 785 } 786 787 // limit loop-depth to 15 bit (only for security reason, it will never be so big) 788 int weight = (cur->loop_depth() & 0x7FFF) << 16; 789 790 // general macro for short definition of weight flags 791 // the first instance of INC_WEIGHT_IF has the highest priority 792 int cur_bit = 15; 793 #define INC_WEIGHT_IF(condition) if ((condition)) { weight |= (1 << cur_bit); } cur_bit--; 794 795 // this is necessery for the (very rare) case that two successing blocks have 796 // the same loop depth, but a different loop index (can happen for endless loops 797 // with exception handlers) 798 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_header_flag)); 799 800 // loop end blocks (blocks that end with a backward branch) are added 801 // after all other blocks of the loop. 802 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_end_flag)); 803 804 // critical edge split blocks are prefered because than they have a bigger 805 // proability to be completely empty 806 INC_WEIGHT_IF(cur->is_set(BlockBegin::critical_edge_split_flag)); 807 808 // exceptions should not be thrown in normal control flow, so these blocks 809 // are added as late as possible 810 INC_WEIGHT_IF(cur->end()->as_Throw() == NULL && (single_sux == NULL || single_sux->end()->as_Throw() == NULL)); 811 INC_WEIGHT_IF(cur->end()->as_Return() == NULL && (single_sux == NULL || single_sux->end()->as_Return() == NULL)); 812 813 // exceptions handlers are added as late as possible 814 INC_WEIGHT_IF(!cur->is_set(BlockBegin::exception_entry_flag)); 815 816 // guarantee that weight is > 0 817 weight |= 1; 818 819 #undef INC_WEIGHT_IF 820 assert(cur_bit >= 0, "too many flags"); 821 assert(weight > 0, "weight cannot become negative"); 822 823 return weight; 824} 825 826bool ComputeLinearScanOrder::ready_for_processing(BlockBegin* cur) { 827 // Discount the edge just traveled. 828 // When the number drops to zero, all forward branches were processed 829 if (dec_forward_branches(cur) != 0) { 830 return false; 831 } 832 833 assert(_linear_scan_order->index_of(cur) == -1, "block already processed (block can be ready only once)"); 834 assert(_work_list.index_of(cur) == -1, "block already in work-list (block can be ready only once)"); 835 return true; 836} 837 838void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) { 839 assert(_work_list.index_of(cur) == -1, "block already in work list"); 840 841 int cur_weight = compute_weight(cur); 842 843 // the linear_scan_number is used to cache the weight of a block 844 cur->set_linear_scan_number(cur_weight); 845 846#ifndef PRODUCT 847 if (StressLinearScan) { 848 _work_list.insert_before(0, cur); 849 return; 850 } 851#endif 852 853 _work_list.append(NULL); // provide space for new element 854 855 int insert_idx = _work_list.length() - 1; 856 while (insert_idx > 0 && _work_list.at(insert_idx - 1)->linear_scan_number() > cur_weight) { 857 _work_list.at_put(insert_idx, _work_list.at(insert_idx - 1)); 858 insert_idx--; 859 } 860 _work_list.at_put(insert_idx, cur); 861 862 TRACE_LINEAR_SCAN(3, tty->print_cr("Sorted B%d into worklist. new worklist:", cur->block_id())); 863 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())); 864 865#ifdef ASSERT 866 for (int i = 0; i < _work_list.length(); i++) { 867 assert(_work_list.at(i)->linear_scan_number() > 0, "weight not set"); 868 assert(i == 0 || _work_list.at(i - 1)->linear_scan_number() <= _work_list.at(i)->linear_scan_number(), "incorrect order in worklist"); 869 } 870#endif 871} 872 873void ComputeLinearScanOrder::append_block(BlockBegin* cur) { 874 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())); 875 assert(_linear_scan_order->index_of(cur) == -1, "cannot add the same block twice"); 876 877 // currently, the linear scan order and code emit order are equal. 878 // therefore the linear_scan_number and the weight of a block must also 879 // be equal. 880 cur->set_linear_scan_number(_linear_scan_order->length()); 881 _linear_scan_order->append(cur); 882} 883 884void ComputeLinearScanOrder::compute_order(BlockBegin* start_block) { 885 TRACE_LINEAR_SCAN(3, "----- computing final block order"); 886 887 // the start block is always the first block in the linear scan order 888 _linear_scan_order = new BlockList(_num_blocks); 889 append_block(start_block); 890 891 assert(start_block->end()->as_Base() != NULL, "start block must end with Base-instruction"); 892 BlockBegin* std_entry = ((Base*)start_block->end())->std_entry(); 893 BlockBegin* osr_entry = ((Base*)start_block->end())->osr_entry(); 894 895 BlockBegin* sux_of_osr_entry = NULL; 896 if (osr_entry != NULL) { 897 // special handling for osr entry: 898 // ignore the edge between the osr entry and its successor for processing 899 // the osr entry block is added manually below 900 assert(osr_entry->number_of_sux() == 1, "osr entry must have exactly one successor"); 901 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"); 902 903 sux_of_osr_entry = osr_entry->sux_at(0); 904 dec_forward_branches(sux_of_osr_entry); 905 906 compute_dominator(osr_entry, start_block); 907 _iterative_dominators = true; 908 } 909 compute_dominator(std_entry, start_block); 910 911 // start processing with standard entry block 912 assert(_work_list.is_empty(), "list must be empty before processing"); 913 914 if (ready_for_processing(std_entry)) { 915 sort_into_work_list(std_entry); 916 } else { 917 assert(false, "the std_entry must be ready for processing (otherwise, the method has no start block)"); 918 } 919 920 do { 921 BlockBegin* cur = _work_list.pop(); 922 923 if (cur == sux_of_osr_entry) { 924 // the osr entry block is ignored in normal processing, it is never added to the 925 // work list. Instead, it is added as late as possible manually here. 926 append_block(osr_entry); 927 compute_dominator(cur, osr_entry); 928 } 929 append_block(cur); 930 931 int i; 932 int num_sux = cur->number_of_sux(); 933 // changed loop order to get "intuitive" order of if- and else-blocks 934 for (i = 0; i < num_sux; i++) { 935 BlockBegin* sux = cur->sux_at(i); 936 compute_dominator(sux, cur); 937 if (ready_for_processing(sux)) { 938 sort_into_work_list(sux); 939 } 940 } 941 num_sux = cur->number_of_exception_handlers(); 942 for (i = 0; i < num_sux; i++) { 943 BlockBegin* sux = cur->exception_handler_at(i); 944 compute_dominator(sux, cur); 945 if (ready_for_processing(sux)) { 946 sort_into_work_list(sux); 947 } 948 } 949 } while (_work_list.length() > 0); 950} 951 952 953bool ComputeLinearScanOrder::compute_dominators_iter() { 954 bool changed = false; 955 int num_blocks = _linear_scan_order->length(); 956 957 assert(_linear_scan_order->at(0)->dominator() == NULL, "must not have dominator"); 958 assert(_linear_scan_order->at(0)->number_of_preds() == 0, "must not have predecessors"); 959 for (int i = 1; i < num_blocks; i++) { 960 BlockBegin* block = _linear_scan_order->at(i); 961 962 BlockBegin* dominator = block->pred_at(0); 963 int num_preds = block->number_of_preds(); 964 for (int i = 1; i < num_preds; i++) { 965 dominator = common_dominator(dominator, block->pred_at(i)); 966 } 967 968 if (dominator != block->dominator()) { 969 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())); 970 971 block->set_dominator(dominator); 972 changed = true; 973 } 974 } 975 return changed; 976} 977 978void ComputeLinearScanOrder::compute_dominators() { 979 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing dominators (iterative computation reqired: %d)", _iterative_dominators)); 980 981 // iterative computation of dominators is only required for methods with non-natural loops 982 // and OSR-methods. For all other methods, the dominators computed when generating the 983 // linear scan block order are correct. 984 if (_iterative_dominators) { 985 do { 986 TRACE_LINEAR_SCAN(1, tty->print_cr("DOM: next iteration of fix-point calculation")); 987 } while (compute_dominators_iter()); 988 } 989 990 // check that dominators are correct 991 assert(!compute_dominators_iter(), "fix point not reached"); 992} 993 994 995#ifndef PRODUCT 996void ComputeLinearScanOrder::print_blocks() { 997 if (TraceLinearScanLevel >= 2) { 998 tty->print_cr("----- loop information:"); 999 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { 1000 BlockBegin* cur = _linear_scan_order->at(block_idx); 1001 1002 tty->print("%4d: B%2d: ", cur->linear_scan_number(), cur->block_id()); 1003 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { 1004 tty->print ("%d ", is_block_in_loop(loop_idx, cur)); 1005 } 1006 tty->print_cr(" -> loop_index: %2d, loop_depth: %2d", cur->loop_index(), cur->loop_depth()); 1007 } 1008 } 1009 1010 if (TraceLinearScanLevel >= 1) { 1011 tty->print_cr("----- linear-scan block order:"); 1012 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { 1013 BlockBegin* cur = _linear_scan_order->at(block_idx); 1014 tty->print("%4d: B%2d loop: %2d depth: %2d", cur->linear_scan_number(), cur->block_id(), cur->loop_index(), cur->loop_depth()); 1015 1016 tty->print(cur->is_set(BlockBegin::exception_entry_flag) ? " ex" : " "); 1017 tty->print(cur->is_set(BlockBegin::critical_edge_split_flag) ? " ce" : " "); 1018 tty->print(cur->is_set(BlockBegin::linear_scan_loop_header_flag) ? " lh" : " "); 1019 tty->print(cur->is_set(BlockBegin::linear_scan_loop_end_flag) ? " le" : " "); 1020 1021 if (cur->dominator() != NULL) { 1022 tty->print(" dom: B%d ", cur->dominator()->block_id()); 1023 } else { 1024 tty->print(" dom: NULL "); 1025 } 1026 1027 if (cur->number_of_preds() > 0) { 1028 tty->print(" preds: "); 1029 for (int j = 0; j < cur->number_of_preds(); j++) { 1030 BlockBegin* pred = cur->pred_at(j); 1031 tty->print("B%d ", pred->block_id()); 1032 } 1033 } 1034 if (cur->number_of_sux() > 0) { 1035 tty->print(" sux: "); 1036 for (int j = 0; j < cur->number_of_sux(); j++) { 1037 BlockBegin* sux = cur->sux_at(j); 1038 tty->print("B%d ", sux->block_id()); 1039 } 1040 } 1041 if (cur->number_of_exception_handlers() > 0) { 1042 tty->print(" ex: "); 1043 for (int j = 0; j < cur->number_of_exception_handlers(); j++) { 1044 BlockBegin* ex = cur->exception_handler_at(j); 1045 tty->print("B%d ", ex->block_id()); 1046 } 1047 } 1048 tty->cr(); 1049 } 1050 } 1051} 1052#endif 1053 1054#ifdef ASSERT 1055void ComputeLinearScanOrder::verify() { 1056 assert(_linear_scan_order->length() == _num_blocks, "wrong number of blocks in list"); 1057 1058 if (StressLinearScan) { 1059 // blocks are scrambled when StressLinearScan is used 1060 return; 1061 } 1062 1063 // check that all successors of a block have a higher linear-scan-number 1064 // and that all predecessors of a block have a lower linear-scan-number 1065 // (only backward branches of loops are ignored) 1066 int i; 1067 for (i = 0; i < _linear_scan_order->length(); i++) { 1068 BlockBegin* cur = _linear_scan_order->at(i); 1069 1070 assert(cur->linear_scan_number() == i, "incorrect linear_scan_number"); 1071 assert(cur->linear_scan_number() >= 0 && cur->linear_scan_number() == _linear_scan_order->index_of(cur), "incorrect linear_scan_number"); 1072 1073 int j; 1074 for (j = cur->number_of_sux() - 1; j >= 0; j--) { 1075 BlockBegin* sux = cur->sux_at(j); 1076 1077 assert(sux->linear_scan_number() >= 0 && sux->linear_scan_number() == _linear_scan_order->index_of(sux), "incorrect linear_scan_number"); 1078 if (!cur->is_set(BlockBegin::linear_scan_loop_end_flag)) { 1079 assert(cur->linear_scan_number() < sux->linear_scan_number(), "invalid order"); 1080 } 1081 if (cur->loop_depth() == sux->loop_depth()) { 1082 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"); 1083 } 1084 } 1085 1086 for (j = cur->number_of_preds() - 1; j >= 0; j--) { 1087 BlockBegin* pred = cur->pred_at(j); 1088 1089 assert(pred->linear_scan_number() >= 0 && pred->linear_scan_number() == _linear_scan_order->index_of(pred), "incorrect linear_scan_number"); 1090 if (!cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { 1091 assert(cur->linear_scan_number() > pred->linear_scan_number(), "invalid order"); 1092 } 1093 if (cur->loop_depth() == pred->loop_depth()) { 1094 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"); 1095 } 1096 1097 assert(cur->dominator()->linear_scan_number() <= cur->pred_at(j)->linear_scan_number(), "dominator must be before predecessors"); 1098 } 1099 1100 // check dominator 1101 if (i == 0) { 1102 assert(cur->dominator() == NULL, "first block has no dominator"); 1103 } else { 1104 assert(cur->dominator() != NULL, "all but first block must have dominator"); 1105 } 1106 assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0), "Single predecessor must also be dominator"); 1107 } 1108 1109 // check that all loops are continuous 1110 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { 1111 int block_idx = 0; 1112 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "the first block must not be present in any loop"); 1113 1114 // skip blocks before the loop 1115 while (block_idx < _num_blocks && !is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { 1116 block_idx++; 1117 } 1118 // skip blocks of loop 1119 while (block_idx < _num_blocks && is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { 1120 block_idx++; 1121 } 1122 // after the first non-loop block, there must not be another loop-block 1123 while (block_idx < _num_blocks) { 1124 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "loop not continuous in linear-scan order"); 1125 block_idx++; 1126 } 1127 } 1128} 1129#endif 1130 1131 1132void IR::compute_code() { 1133 assert(is_valid(), "IR must be valid"); 1134 1135 ComputeLinearScanOrder compute_order(start()); 1136 _num_loops = compute_order.num_loops(); 1137 _code = compute_order.linear_scan_order(); 1138} 1139 1140 1141void IR::compute_use_counts() { 1142 // make sure all values coming out of this block get evaluated. 1143 int num_blocks = _code->length(); 1144 for (int i = 0; i < num_blocks; i++) { 1145 _code->at(i)->end()->state()->pin_stack_for_linear_scan(); 1146 } 1147 1148 // compute use counts 1149 UseCountComputer::compute(_code); 1150} 1151 1152 1153void IR::iterate_preorder(BlockClosure* closure) { 1154 assert(is_valid(), "IR must be valid"); 1155 start()->iterate_preorder(closure); 1156} 1157 1158 1159void IR::iterate_postorder(BlockClosure* closure) { 1160 assert(is_valid(), "IR must be valid"); 1161 start()->iterate_postorder(closure); 1162} 1163 1164void IR::iterate_linear_scan_order(BlockClosure* closure) { 1165 linear_scan_order()->iterate_forward(closure); 1166} 1167 1168 1169#ifndef PRODUCT 1170class BlockPrinter: public BlockClosure { 1171 private: 1172 InstructionPrinter* _ip; 1173 bool _cfg_only; 1174 bool _live_only; 1175 1176 public: 1177 BlockPrinter(InstructionPrinter* ip, bool cfg_only, bool live_only = false) { 1178 _ip = ip; 1179 _cfg_only = cfg_only; 1180 _live_only = live_only; 1181 } 1182 1183 virtual void block_do(BlockBegin* block) { 1184 if (_cfg_only) { 1185 _ip->print_instr(block); tty->cr(); 1186 } else { 1187 block->print_block(*_ip, _live_only); 1188 } 1189 } 1190}; 1191 1192 1193void IR::print(BlockBegin* start, bool cfg_only, bool live_only) { 1194 ttyLocker ttyl; 1195 InstructionPrinter ip(!cfg_only); 1196 BlockPrinter bp(&ip, cfg_only, live_only); 1197 start->iterate_preorder(&bp); 1198 tty->cr(); 1199} 1200 1201void IR::print(bool cfg_only, bool live_only) { 1202 if (is_valid()) { 1203 print(start(), cfg_only, live_only); 1204 } else { 1205 tty->print_cr("invalid IR"); 1206 } 1207} 1208 1209 1210define_array(BlockListArray, BlockList*) 1211define_stack(BlockListList, BlockListArray) 1212 1213class PredecessorValidator : public BlockClosure { 1214 private: 1215 BlockListList* _predecessors; 1216 BlockList* _blocks; 1217 1218 static int cmp(BlockBegin** a, BlockBegin** b) { 1219 return (*a)->block_id() - (*b)->block_id(); 1220 } 1221 1222 public: 1223 PredecessorValidator(IR* hir) { 1224 ResourceMark rm; 1225 _predecessors = new BlockListList(BlockBegin::number_of_blocks(), NULL); 1226 _blocks = new BlockList(); 1227 1228 int i; 1229 hir->start()->iterate_preorder(this); 1230 if (hir->code() != NULL) { 1231 assert(hir->code()->length() == _blocks->length(), "must match"); 1232 for (i = 0; i < _blocks->length(); i++) { 1233 assert(hir->code()->contains(_blocks->at(i)), "should be in both lists"); 1234 } 1235 } 1236 1237 for (i = 0; i < _blocks->length(); i++) { 1238 BlockBegin* block = _blocks->at(i); 1239 BlockList* preds = _predecessors->at(block->block_id()); 1240 if (preds == NULL) { 1241 assert(block->number_of_preds() == 0, "should be the same"); 1242 continue; 1243 } 1244 1245 // clone the pred list so we can mutate it 1246 BlockList* pred_copy = new BlockList(); 1247 int j; 1248 for (j = 0; j < block->number_of_preds(); j++) { 1249 pred_copy->append(block->pred_at(j)); 1250 } 1251 // sort them in the same order 1252 preds->sort(cmp); 1253 pred_copy->sort(cmp); 1254 int length = MIN2(preds->length(), block->number_of_preds()); 1255 for (j = 0; j < block->number_of_preds(); j++) { 1256 assert(preds->at(j) == pred_copy->at(j), "must match"); 1257 } 1258 1259 assert(preds->length() == block->number_of_preds(), "should be the same"); 1260 } 1261 } 1262 1263 virtual void block_do(BlockBegin* block) { 1264 _blocks->append(block); 1265 BlockEnd* be = block->end(); 1266 int n = be->number_of_sux(); 1267 int i; 1268 for (i = 0; i < n; i++) { 1269 BlockBegin* sux = be->sux_at(i); 1270 assert(!sux->is_set(BlockBegin::exception_entry_flag), "must not be xhandler"); 1271 1272 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); 1273 if (preds == NULL) { 1274 preds = new BlockList(); 1275 _predecessors->at_put(sux->block_id(), preds); 1276 } 1277 preds->append(block); 1278 } 1279 1280 n = block->number_of_exception_handlers(); 1281 for (i = 0; i < n; i++) { 1282 BlockBegin* sux = block->exception_handler_at(i); 1283 assert(sux->is_set(BlockBegin::exception_entry_flag), "must be xhandler"); 1284 1285 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); 1286 if (preds == NULL) { 1287 preds = new BlockList(); 1288 _predecessors->at_put(sux->block_id(), preds); 1289 } 1290 preds->append(block); 1291 } 1292 } 1293}; 1294 1295void IR::verify() { 1296#ifdef ASSERT 1297 PredecessorValidator pv(this); 1298#endif 1299} 1300 1301#endif // PRODUCT 1302 1303void SubstitutionResolver::substitute(Value* v) { 1304 Value v0 = *v; 1305 if (v0) { 1306 Value vs = v0->subst(); 1307 if (vs != v0) { 1308 *v = v0->subst(); 1309 } 1310 } 1311} 1312 1313#ifdef ASSERT 1314void check_substitute(Value* v) { 1315 Value v0 = *v; 1316 if (v0) { 1317 Value vs = v0->subst(); 1318 assert(vs == v0, "missed substitution"); 1319 } 1320} 1321#endif 1322 1323 1324void SubstitutionResolver::block_do(BlockBegin* block) { 1325 Instruction* last = NULL; 1326 for (Instruction* n = block; n != NULL;) { 1327 n->values_do(substitute); 1328 // need to remove this instruction from the instruction stream 1329 if (n->subst() != n) { 1330 assert(last != NULL, "must have last"); 1331 last->set_next(n->next(), n->next()->bci()); 1332 } else { 1333 last = n; 1334 } 1335 n = last->next(); 1336 } 1337 1338#ifdef ASSERT 1339 if (block->state()) block->state()->values_do(check_substitute); 1340 block->block_values_do(check_substitute); 1341 if (block->end() && block->end()->state()) block->end()->state()->values_do(check_substitute); 1342#endif 1343} 1344