1 /* 2 * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "c1/c1_Compilation.hpp" 27 #include "c1/c1_FrameMap.hpp" 28 #include "c1/c1_GraphBuilder.hpp" 29 #include "c1/c1_IR.hpp" 30 #include "c1/c1_InstructionPrinter.hpp" 31 #include "c1/c1_Optimizer.hpp" 32 #include "utilities/bitMap.inline.hpp" 33 34 35 // Implementation of XHandlers 36 // 37 // Note: This code could eventually go away if we are 38 // just using the ciExceptionHandlerStream. 39 40 XHandlers::XHandlers(ciMethod* method) : _list(method->exception_table_length()) { 41 ciExceptionHandlerStream s(method); 42 while (!s.is_done()) { 43 _list.append(new XHandler(s.handler())); 44 s.next(); 45 } 46 assert(s.count() == method->exception_table_length(), "exception table lengths inconsistent"); 47 } 48 49 // deep copy of all XHandler contained in list 50 XHandlers::XHandlers(XHandlers* other) : 51 _list(other->length()) 52 { 53 for (int i = 0; i < other->length(); i++) { 54 _list.append(new XHandler(other->handler_at(i))); 55 } 56 } 57 58 // Returns whether a particular exception type can be caught. Also 59 // returns true if klass is unloaded or any exception handler 60 // classes are unloaded. type_is_exact indicates whether the throw 61 // is known to be exactly that class or it might throw a subtype. 62 bool XHandlers::could_catch(ciInstanceKlass* klass, bool type_is_exact) const { 63 // the type is unknown so be conservative 64 if (!klass->is_loaded()) { 65 return true; 66 } 67 68 for (int i = 0; i < length(); i++) { 69 XHandler* handler = handler_at(i); 70 if (handler->is_catch_all()) { 71 // catch of ANY 72 return true; 73 } 74 ciInstanceKlass* handler_klass = handler->catch_klass(); 75 // if it's unknown it might be catchable 76 if (!handler_klass->is_loaded()) { 77 return true; 78 } 79 // if the throw type is definitely a subtype of the catch type 80 // then it can be caught. 81 if (klass->is_subtype_of(handler_klass)) { 82 return true; 83 } 84 if (!type_is_exact) { 85 // If the type isn't exactly known then it can also be caught by 86 // catch statements where the inexact type is a subtype of the 87 // catch type. 88 // given: foo extends bar extends Exception 89 // throw bar can be caught by catch foo, catch bar, and catch 90 // Exception, however it can't be caught by any handlers without 91 // bar in its type hierarchy. 92 if (handler_klass->is_subtype_of(klass)) { 93 return true; 94 } 95 } 96 } 97 98 return false; 99 } 100 101 102 bool XHandlers::equals(XHandlers* others) const { 103 if (others == NULL) return false; 104 if (length() != others->length()) return false; 105 106 for (int i = 0; i < length(); i++) { 107 if (!handler_at(i)->equals(others->handler_at(i))) return false; 108 } 109 return true; 110 } 111 112 bool XHandler::equals(XHandler* other) const { 113 assert(entry_pco() != -1 && other->entry_pco() != -1, "must have entry_pco"); 114 115 if (entry_pco() != other->entry_pco()) return false; 116 if (scope_count() != other->scope_count()) return false; 117 if (_desc != other->_desc) return false; 118 119 assert(entry_block() == other->entry_block(), "entry_block must be equal when entry_pco is equal"); 120 return true; 121 } 122 123 124 // Implementation of IRScope 125 BlockBegin* IRScope::build_graph(Compilation* compilation, int osr_bci) { 126 GraphBuilder gm(compilation, this); 127 NOT_PRODUCT(if (PrintValueNumbering && Verbose) gm.print_stats()); 128 if (compilation->bailed_out()) return NULL; 129 return gm.start(); 130 } 131 132 133 IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMethod* method, int osr_bci, bool create_graph) 134 : _callees(2) 135 , _compilation(compilation) 136 , _requires_phi_function(method->max_locals()) 137 { 138 _caller = caller; 139 _level = caller == NULL ? 0 : caller->level() + 1; 140 _method = method; 141 _xhandlers = new XHandlers(method); 142 _number_of_locks = 0; 143 _monitor_pairing_ok = method->has_balanced_monitors(); 144 _wrote_final = false; 145 _start = NULL; 146 147 if (osr_bci == -1) { 148 _requires_phi_function.clear(); 149 } else { 150 // selective creation of phi functions is not possibel in osr-methods 151 _requires_phi_function.set_range(0, method->max_locals()); 152 } 153 154 assert(method->holder()->is_loaded() , "method holder must be loaded"); 155 156 // build graph if monitor pairing is ok 157 if (create_graph && monitor_pairing_ok()) _start = build_graph(compilation, osr_bci); 158 } 159 160 161 int IRScope::max_stack() const { 162 int my_max = method()->max_stack(); 163 int callee_max = 0; 164 for (int i = 0; i < number_of_callees(); i++) { 165 callee_max = MAX2(callee_max, callee_no(i)->max_stack()); 166 } 167 return my_max + callee_max; 168 } 169 170 171 bool IRScopeDebugInfo::should_reexecute() { 172 ciMethod* cur_method = scope()->method(); 173 int cur_bci = bci(); 174 if (cur_method != NULL && cur_bci != SynchronizationEntryBCI) { 175 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci); 176 return Interpreter::bytecode_should_reexecute(code); 177 } else 178 return false; 179 } 180 181 182 // Implementation of CodeEmitInfo 183 184 // Stack must be NON-null 185 CodeEmitInfo::CodeEmitInfo(ValueStack* stack, XHandlers* exception_handlers) 186 : _scope(stack->scope()) 187 , _scope_debug_info(NULL) 188 , _oop_map(NULL) 189 , _stack(stack) 190 , _exception_handlers(exception_handlers) 191 , _is_method_handle_invoke(false) { 192 assert(_stack != NULL, "must be non null"); 193 } 194 195 196 CodeEmitInfo::CodeEmitInfo(CodeEmitInfo* info, ValueStack* stack) 197 : _scope(info->_scope) 198 , _exception_handlers(NULL) 199 , _scope_debug_info(NULL) 200 , _oop_map(NULL) 201 , _stack(stack == NULL ? info->_stack : stack) 202 , _is_method_handle_invoke(info->_is_method_handle_invoke) { 203 204 // deep copy of exception handlers 205 if (info->_exception_handlers != NULL) { 206 _exception_handlers = new XHandlers(info->_exception_handlers); 207 } 208 } 209 210 211 void CodeEmitInfo::record_debug_info(DebugInformationRecorder* recorder, int pc_offset) { 212 // record the safepoint before recording the debug info for enclosing scopes 213 recorder->add_safepoint(pc_offset, _oop_map->deep_copy()); 214 _scope_debug_info->record_debug_info(recorder, pc_offset, true/*topmost*/, _is_method_handle_invoke); 215 recorder->end_safepoint(pc_offset); 216 } 217 218 219 void CodeEmitInfo::add_register_oop(LIR_Opr opr) { 220 assert(_oop_map != NULL, "oop map must already exist"); 221 assert(opr->is_single_cpu(), "should not call otherwise"); 222 223 VMReg name = frame_map()->regname(opr); 224 _oop_map->set_oop(name); 225 } 226 227 228 229 230 // Implementation of IR 231 232 IR::IR(Compilation* compilation, ciMethod* method, int osr_bci) : 233 _locals_size(in_WordSize(-1)) 234 , _num_loops(0) { 235 // setup IR fields 236 _compilation = compilation; 237 _top_scope = new IRScope(compilation, NULL, -1, method, osr_bci, true); 238 _code = NULL; 239 } 240 241 242 void IR::optimize() { 243 Optimizer opt(this); 244 if (!compilation()->profile_branches()) { 245 if (DoCEE) { 246 opt.eliminate_conditional_expressions(); 247 #ifndef PRODUCT 248 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after CEE"); print(true); } 249 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after CEE"); print(false); } 250 #endif 251 } 252 if (EliminateBlocks) { 253 opt.eliminate_blocks(); 254 #ifndef PRODUCT 255 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after block elimination"); print(true); } 256 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after block elimination"); print(false); } 257 #endif 258 } 259 } 260 if (EliminateNullChecks) { 261 opt.eliminate_null_checks(); 262 #ifndef PRODUCT 263 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after null check elimination"); print(true); } 264 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after null check elimination"); print(false); } 265 #endif 266 } 267 } 268 269 270 static int sort_pairs(BlockPair** a, BlockPair** b) { 271 if ((*a)->from() == (*b)->from()) { 272 return (*a)->to()->block_id() - (*b)->to()->block_id(); 273 } else { 274 return (*a)->from()->block_id() - (*b)->from()->block_id(); 275 } 276 } 277 278 279 class CriticalEdgeFinder: public BlockClosure { 280 BlockPairList blocks; 281 IR* _ir; 282 283 public: 284 CriticalEdgeFinder(IR* ir): _ir(ir) {} 285 void block_do(BlockBegin* bb) { 286 BlockEnd* be = bb->end(); 287 int nos = be->number_of_sux(); 288 if (nos >= 2) { 289 for (int i = 0; i < nos; i++) { 290 BlockBegin* sux = be->sux_at(i); 291 if (sux->number_of_preds() >= 2) { 292 blocks.append(new BlockPair(bb, sux)); 293 } 294 } 295 } 296 } 297 298 void split_edges() { 299 BlockPair* last_pair = NULL; 300 blocks.sort(sort_pairs); 301 for (int i = 0; i < blocks.length(); i++) { 302 BlockPair* pair = blocks.at(i); 303 if (last_pair != NULL && pair->is_same(last_pair)) continue; 304 BlockBegin* from = pair->from(); 305 BlockBegin* to = pair->to(); 306 BlockBegin* split = from->insert_block_between(to); 307 #ifndef PRODUCT 308 if ((PrintIR || PrintIR1) && Verbose) { 309 tty->print_cr("Split critical edge B%d -> B%d (new block B%d)", 310 from->block_id(), to->block_id(), split->block_id()); 311 } 312 #endif 313 last_pair = pair; 314 } 315 } 316 }; 317 318 void IR::split_critical_edges() { 319 CriticalEdgeFinder cef(this); 320 321 iterate_preorder(&cef); 322 cef.split_edges(); 323 } 324 325 326 class UseCountComputer: public ValueVisitor, BlockClosure { 327 private: 328 void visit(Value* n) { 329 // Local instructions and Phis for expression stack values at the 330 // start of basic blocks are not added to the instruction list 331 if (!(*n)->is_linked() && (*n)->can_be_linked()) { 332 assert(false, "a node was not appended to the graph"); 333 Compilation::current()->bailout("a node was not appended to the graph"); 334 } 335 // use n's input if not visited before 336 if (!(*n)->is_pinned() && !(*n)->has_uses()) { 337 // note: a) if the instruction is pinned, it will be handled by compute_use_count 338 // b) if the instruction has uses, it was touched before 339 // => in both cases we don't need to update n's values 340 uses_do(n); 341 } 342 // use n 343 (*n)->_use_count++; 344 } 345 346 Values* worklist; 347 int depth; 348 enum { 349 max_recurse_depth = 20 350 }; 351 352 void uses_do(Value* n) { 353 depth++; 354 if (depth > max_recurse_depth) { 355 // don't allow the traversal to recurse too deeply 356 worklist->push(*n); 357 } else { 358 (*n)->input_values_do(this); 359 // special handling for some instructions 360 if ((*n)->as_BlockEnd() != NULL) { 361 // note on BlockEnd: 362 // must 'use' the stack only if the method doesn't 363 // terminate, however, in those cases stack is empty 364 (*n)->state_values_do(this); 365 } 366 } 367 depth--; 368 } 369 370 void block_do(BlockBegin* b) { 371 depth = 0; 372 // process all pinned nodes as the roots of expression trees 373 for (Instruction* n = b; n != NULL; n = n->next()) { 374 if (n->is_pinned()) uses_do(&n); 375 } 376 assert(depth == 0, "should have counted back down"); 377 378 // now process any unpinned nodes which recursed too deeply 379 while (worklist->length() > 0) { 380 Value t = worklist->pop(); 381 if (!t->is_pinned()) { 382 // compute the use count 383 uses_do(&t); 384 385 // pin the instruction so that LIRGenerator doesn't recurse 386 // too deeply during it's evaluation. 387 t->pin(); 388 } 389 } 390 assert(depth == 0, "should have counted back down"); 391 } 392 393 UseCountComputer() { 394 worklist = new Values(); 395 depth = 0; 396 } 397 398 public: 399 static void compute(BlockList* blocks) { 400 UseCountComputer ucc; 401 blocks->iterate_backward(&ucc); 402 } 403 }; 404 405 406 // helper macro for short definition of trace-output inside code 407 #ifndef PRODUCT 408 #define TRACE_LINEAR_SCAN(level, code) \ 409 if (TraceLinearScanLevel >= level) { \ 410 code; \ 411 } 412 #else 413 #define TRACE_LINEAR_SCAN(level, code) 414 #endif 415 416 class ComputeLinearScanOrder : public StackObj { 417 private: 418 int _max_block_id; // the highest block_id of a block 419 int _num_blocks; // total number of blocks (smaller than _max_block_id) 420 int _num_loops; // total number of loops 421 bool _iterative_dominators;// method requires iterative computation of dominatiors 422 423 BlockList* _linear_scan_order; // the resulting list of blocks in correct order 424 425 BitMap _visited_blocks; // used for recursive processing of blocks 426 BitMap _active_blocks; // used for recursive processing of blocks 427 BitMap _dominator_blocks; // temproary BitMap used for computation of dominator 428 intArray _forward_branches; // number of incoming forward branches for each block 429 BlockList _loop_end_blocks; // list of all loop end blocks collected during count_edges 430 BitMap2D _loop_map; // two-dimensional bit set: a bit is set if a block is contained in a loop 431 BlockList _work_list; // temporary list (used in mark_loops and compute_order) 432 433 Compilation* _compilation; 434 435 // accessors for _visited_blocks and _active_blocks 436 void init_visited() { _active_blocks.clear(); _visited_blocks.clear(); } 437 bool is_visited(BlockBegin* b) const { return _visited_blocks.at(b->block_id()); } 438 bool is_active(BlockBegin* b) const { return _active_blocks.at(b->block_id()); } 439 void set_visited(BlockBegin* b) { assert(!is_visited(b), "already set"); _visited_blocks.set_bit(b->block_id()); } 440 void set_active(BlockBegin* b) { assert(!is_active(b), "already set"); _active_blocks.set_bit(b->block_id()); } 441 void clear_active(BlockBegin* b) { assert(is_active(b), "not already"); _active_blocks.clear_bit(b->block_id()); } 442 443 // accessors for _forward_branches 444 void inc_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) + 1); } 445 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()); } 446 447 // accessors for _loop_map 448 bool is_block_in_loop (int loop_idx, BlockBegin* b) const { return _loop_map.at(loop_idx, b->block_id()); } 449 void set_block_in_loop (int loop_idx, BlockBegin* b) { _loop_map.set_bit(loop_idx, b->block_id()); } 450 void clear_block_in_loop(int loop_idx, int block_id) { _loop_map.clear_bit(loop_idx, block_id); } 451 452 // count edges between blocks 453 void count_edges(BlockBegin* cur, BlockBegin* parent); 454 455 // loop detection 456 void mark_loops(); 457 void clear_non_natural_loops(BlockBegin* start_block); 458 void assign_loop_depth(BlockBegin* start_block); 459 460 // computation of final block order 461 BlockBegin* common_dominator(BlockBegin* a, BlockBegin* b); 462 void compute_dominator(BlockBegin* cur, BlockBegin* parent); 463 int compute_weight(BlockBegin* cur); 464 bool ready_for_processing(BlockBegin* cur); 465 void sort_into_work_list(BlockBegin* b); 466 void append_block(BlockBegin* cur); 467 void compute_order(BlockBegin* start_block); 468 469 // fixup of dominators for non-natural loops 470 bool compute_dominators_iter(); 471 void compute_dominators(); 472 473 // debug functions 474 NOT_PRODUCT(void print_blocks();) 475 DEBUG_ONLY(void verify();) 476 477 Compilation* compilation() const { return _compilation; } 478 public: 479 ComputeLinearScanOrder(Compilation* c, BlockBegin* start_block); 480 481 // accessors for final result 482 BlockList* linear_scan_order() const { return _linear_scan_order; } 483 int num_loops() const { return _num_loops; } 484 }; 485 486 487 ComputeLinearScanOrder::ComputeLinearScanOrder(Compilation* c, BlockBegin* start_block) : 488 _max_block_id(BlockBegin::number_of_blocks()), 489 _num_blocks(0), 490 _num_loops(0), 491 _iterative_dominators(false), 492 _visited_blocks(_max_block_id), 493 _active_blocks(_max_block_id), 494 _dominator_blocks(_max_block_id), 495 _forward_branches(_max_block_id, 0), 496 _loop_end_blocks(8), 497 _work_list(8), 498 _linear_scan_order(NULL), // initialized later with correct size 499 _loop_map(0, 0), // initialized later with correct size 500 _compilation(c) 501 { 502 TRACE_LINEAR_SCAN(2, "***** computing linear-scan block order"); 503 504 init_visited(); 505 count_edges(start_block, NULL); 506 507 if (compilation()->is_profiling()) { 508 ciMethod *method = compilation()->method(); 509 if (!method->is_accessor()) { 510 ciMethodData* md = method->method_data_or_null(); 511 assert(md != NULL, "Sanity"); 512 md->set_compilation_stats(_num_loops, _num_blocks); 513 } 514 } 515 516 if (_num_loops > 0) { 517 mark_loops(); 518 clear_non_natural_loops(start_block); 519 assign_loop_depth(start_block); 520 } 521 522 compute_order(start_block); 523 compute_dominators(); 524 525 NOT_PRODUCT(print_blocks()); 526 DEBUG_ONLY(verify()); 527 } 528 529 530 // Traverse the CFG: 531 // * count total number of blocks 532 // * count all incoming edges and backward incoming edges 533 // * number loop header blocks 534 // * create a list with all loop end blocks 535 void ComputeLinearScanOrder::count_edges(BlockBegin* cur, BlockBegin* parent) { 536 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)); 537 assert(cur->dominator() == NULL, "dominator already initialized"); 538 539 if (is_active(cur)) { 540 TRACE_LINEAR_SCAN(3, tty->print_cr("backward branch")); 541 assert(is_visited(cur), "block must be visisted when block is active"); 542 assert(parent != NULL, "must have parent"); 543 544 cur->set(BlockBegin::linear_scan_loop_header_flag); 545 cur->set(BlockBegin::backward_branch_target_flag); 546 547 parent->set(BlockBegin::linear_scan_loop_end_flag); 548 549 // When a loop header is also the start of an exception handler, then the backward branch is 550 // an exception edge. Because such edges are usually critical edges which cannot be split, the 551 // loop must be excluded here from processing. 552 if (cur->is_set(BlockBegin::exception_entry_flag)) { 553 // Make sure that dominators are correct in this weird situation 554 _iterative_dominators = true; 555 return; 556 } 557 assert(parent->number_of_sux() == 1 && parent->sux_at(0) == cur, 558 "loop end blocks must have one successor (critical edges are split)"); 559 560 _loop_end_blocks.append(parent); 561 return; 562 } 563 564 // increment number of incoming forward branches 565 inc_forward_branches(cur); 566 567 if (is_visited(cur)) { 568 TRACE_LINEAR_SCAN(3, tty->print_cr("block already visited")); 569 return; 570 } 571 572 _num_blocks++; 573 set_visited(cur); 574 set_active(cur); 575 576 // recursive call for all successors 577 int i; 578 for (i = cur->number_of_sux() - 1; i >= 0; i--) { 579 count_edges(cur->sux_at(i), cur); 580 } 581 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { 582 count_edges(cur->exception_handler_at(i), cur); 583 } 584 585 clear_active(cur); 586 587 // Each loop has a unique number. 588 // When multiple loops are nested, assign_loop_depth assumes that the 589 // innermost loop has the lowest number. This is guaranteed by setting 590 // the loop number after the recursive calls for the successors above 591 // have returned. 592 if (cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { 593 assert(cur->loop_index() == -1, "cannot set loop-index twice"); 594 TRACE_LINEAR_SCAN(3, tty->print_cr("Block B%d is loop header of loop %d", cur->block_id(), _num_loops)); 595 596 cur->set_loop_index(_num_loops); 597 _num_loops++; 598 } 599 600 TRACE_LINEAR_SCAN(3, tty->print_cr("Finished count_edges for block B%d", cur->block_id())); 601 } 602 603 604 void ComputeLinearScanOrder::mark_loops() { 605 TRACE_LINEAR_SCAN(3, tty->print_cr("----- marking loops")); 606 607 _loop_map = BitMap2D(_num_loops, _max_block_id); 608 _loop_map.clear(); 609 610 for (int i = _loop_end_blocks.length() - 1; i >= 0; i--) { 611 BlockBegin* loop_end = _loop_end_blocks.at(i); 612 BlockBegin* loop_start = loop_end->sux_at(0); 613 int loop_idx = loop_start->loop_index(); 614 615 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)); 616 assert(loop_end->is_set(BlockBegin::linear_scan_loop_end_flag), "loop end flag must be set"); 617 assert(loop_end->number_of_sux() == 1, "incorrect number of successors"); 618 assert(loop_start->is_set(BlockBegin::linear_scan_loop_header_flag), "loop header flag must be set"); 619 assert(loop_idx >= 0 && loop_idx < _num_loops, "loop index not set"); 620 assert(_work_list.is_empty(), "work list must be empty before processing"); 621 622 // add the end-block of the loop to the working list 623 _work_list.push(loop_end); 624 set_block_in_loop(loop_idx, loop_end); 625 do { 626 BlockBegin* cur = _work_list.pop(); 627 628 TRACE_LINEAR_SCAN(3, tty->print_cr(" processing B%d", cur->block_id())); 629 assert(is_block_in_loop(loop_idx, cur), "bit in loop map must be set when block is in work list"); 630 631 // recursive processing of all predecessors ends when start block of loop is reached 632 if (cur != loop_start && !cur->is_set(BlockBegin::osr_entry_flag)) { 633 for (int j = cur->number_of_preds() - 1; j >= 0; j--) { 634 BlockBegin* pred = cur->pred_at(j); 635 636 if (!is_block_in_loop(loop_idx, pred) /*&& !pred->is_set(BlockBeginosr_entry_flag)*/) { 637 // this predecessor has not been processed yet, so add it to work list 638 TRACE_LINEAR_SCAN(3, tty->print_cr(" pushing B%d", pred->block_id())); 639 _work_list.push(pred); 640 set_block_in_loop(loop_idx, pred); 641 } 642 } 643 } 644 } while (!_work_list.is_empty()); 645 } 646 } 647 648 649 // check for non-natural loops (loops where the loop header does not dominate 650 // all other loop blocks = loops with mulitple entries). 651 // such loops are ignored 652 void ComputeLinearScanOrder::clear_non_natural_loops(BlockBegin* start_block) { 653 for (int i = _num_loops - 1; i >= 0; i--) { 654 if (is_block_in_loop(i, start_block)) { 655 // loop i contains the entry block of the method 656 // -> this is not a natural loop, so ignore it 657 TRACE_LINEAR_SCAN(2, tty->print_cr("Loop %d is non-natural, so it is ignored", i)); 658 659 for (int block_id = _max_block_id - 1; block_id >= 0; block_id--) { 660 clear_block_in_loop(i, block_id); 661 } 662 _iterative_dominators = true; 663 } 664 } 665 } 666 667 void ComputeLinearScanOrder::assign_loop_depth(BlockBegin* start_block) { 668 TRACE_LINEAR_SCAN(3, "----- computing loop-depth and weight"); 669 init_visited(); 670 671 assert(_work_list.is_empty(), "work list must be empty before processing"); 672 _work_list.append(start_block); 673 674 do { 675 BlockBegin* cur = _work_list.pop(); 676 677 if (!is_visited(cur)) { 678 set_visited(cur); 679 TRACE_LINEAR_SCAN(4, tty->print_cr("Computing loop depth for block B%d", cur->block_id())); 680 681 // compute loop-depth and loop-index for the block 682 assert(cur->loop_depth() == 0, "cannot set loop-depth twice"); 683 int i; 684 int loop_depth = 0; 685 int min_loop_idx = -1; 686 for (i = _num_loops - 1; i >= 0; i--) { 687 if (is_block_in_loop(i, cur)) { 688 loop_depth++; 689 min_loop_idx = i; 690 } 691 } 692 cur->set_loop_depth(loop_depth); 693 cur->set_loop_index(min_loop_idx); 694 695 // append all unvisited successors to work list 696 for (i = cur->number_of_sux() - 1; i >= 0; i--) { 697 _work_list.append(cur->sux_at(i)); 698 } 699 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { 700 _work_list.append(cur->exception_handler_at(i)); 701 } 702 } 703 } while (!_work_list.is_empty()); 704 } 705 706 707 BlockBegin* ComputeLinearScanOrder::common_dominator(BlockBegin* a, BlockBegin* b) { 708 assert(a != NULL && b != NULL, "must have input blocks"); 709 710 _dominator_blocks.clear(); 711 while (a != NULL) { 712 _dominator_blocks.set_bit(a->block_id()); 713 assert(a->dominator() != NULL || a == _linear_scan_order->at(0), "dominator must be initialized"); 714 a = a->dominator(); 715 } 716 while (b != NULL && !_dominator_blocks.at(b->block_id())) { 717 assert(b->dominator() != NULL || b == _linear_scan_order->at(0), "dominator must be initialized"); 718 b = b->dominator(); 719 } 720 721 assert(b != NULL, "could not find dominator"); 722 return b; 723 } 724 725 void ComputeLinearScanOrder::compute_dominator(BlockBegin* cur, BlockBegin* parent) { 726 if (cur->dominator() == NULL) { 727 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: initializing dominator of B%d to B%d", cur->block_id(), parent->block_id())); 728 cur->set_dominator(parent); 729 730 } else if (!(cur->is_set(BlockBegin::linear_scan_loop_header_flag) && parent->is_set(BlockBegin::linear_scan_loop_end_flag))) { 731 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())); 732 assert(cur->number_of_preds() > 1, ""); 733 cur->set_dominator(common_dominator(cur->dominator(), parent)); 734 } 735 } 736 737 738 int ComputeLinearScanOrder::compute_weight(BlockBegin* cur) { 739 BlockBegin* single_sux = NULL; 740 if (cur->number_of_sux() == 1) { 741 single_sux = cur->sux_at(0); 742 } 743 744 // limit loop-depth to 15 bit (only for security reason, it will never be so big) 745 int weight = (cur->loop_depth() & 0x7FFF) << 16; 746 747 // general macro for short definition of weight flags 748 // the first instance of INC_WEIGHT_IF has the highest priority 749 int cur_bit = 15; 750 #define INC_WEIGHT_IF(condition) if ((condition)) { weight |= (1 << cur_bit); } cur_bit--; 751 752 // this is necessery for the (very rare) case that two successing blocks have 753 // the same loop depth, but a different loop index (can happen for endless loops 754 // with exception handlers) 755 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_header_flag)); 756 757 // loop end blocks (blocks that end with a backward branch) are added 758 // after all other blocks of the loop. 759 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_end_flag)); 760 761 // critical edge split blocks are prefered because than they have a bigger 762 // proability to be completely empty 763 INC_WEIGHT_IF(cur->is_set(BlockBegin::critical_edge_split_flag)); 764 765 // exceptions should not be thrown in normal control flow, so these blocks 766 // are added as late as possible 767 INC_WEIGHT_IF(cur->end()->as_Throw() == NULL && (single_sux == NULL || single_sux->end()->as_Throw() == NULL)); 768 INC_WEIGHT_IF(cur->end()->as_Return() == NULL && (single_sux == NULL || single_sux->end()->as_Return() == NULL)); 769 770 // exceptions handlers are added as late as possible 771 INC_WEIGHT_IF(!cur->is_set(BlockBegin::exception_entry_flag)); 772 773 // guarantee that weight is > 0 774 weight |= 1; 775 776 #undef INC_WEIGHT_IF 777 assert(cur_bit >= 0, "too many flags"); 778 assert(weight > 0, "weight cannot become negative"); 779 780 return weight; 781 } 782 783 bool ComputeLinearScanOrder::ready_for_processing(BlockBegin* cur) { 784 // Discount the edge just traveled. 785 // When the number drops to zero, all forward branches were processed 786 if (dec_forward_branches(cur) != 0) { 787 return false; 788 } 789 790 assert(_linear_scan_order->index_of(cur) == -1, "block already processed (block can be ready only once)"); 791 assert(_work_list.index_of(cur) == -1, "block already in work-list (block can be ready only once)"); 792 return true; 793 } 794 795 void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) { 796 assert(_work_list.index_of(cur) == -1, "block already in work list"); 797 798 int cur_weight = compute_weight(cur); 799 800 // the linear_scan_number is used to cache the weight of a block 801 cur->set_linear_scan_number(cur_weight); 802 803 #ifndef PRODUCT 804 if (StressLinearScan) { 805 _work_list.insert_before(0, cur); 806 return; 807 } 808 #endif 809 810 _work_list.append(NULL); // provide space for new element 811 812 int insert_idx = _work_list.length() - 1; 813 while (insert_idx > 0 && _work_list.at(insert_idx - 1)->linear_scan_number() > cur_weight) { 814 _work_list.at_put(insert_idx, _work_list.at(insert_idx - 1)); 815 insert_idx--; 816 } 817 _work_list.at_put(insert_idx, cur); 818 819 TRACE_LINEAR_SCAN(3, tty->print_cr("Sorted B%d into worklist. new worklist:", cur->block_id())); 820 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())); 821 822 #ifdef ASSERT 823 for (int i = 0; i < _work_list.length(); i++) { 824 assert(_work_list.at(i)->linear_scan_number() > 0, "weight not set"); 825 assert(i == 0 || _work_list.at(i - 1)->linear_scan_number() <= _work_list.at(i)->linear_scan_number(), "incorrect order in worklist"); 826 } 827 #endif 828 } 829 830 void ComputeLinearScanOrder::append_block(BlockBegin* cur) { 831 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())); 832 assert(_linear_scan_order->index_of(cur) == -1, "cannot add the same block twice"); 833 834 // currently, the linear scan order and code emit order are equal. 835 // therefore the linear_scan_number and the weight of a block must also 836 // be equal. 837 cur->set_linear_scan_number(_linear_scan_order->length()); 838 _linear_scan_order->append(cur); 839 } 840 841 void ComputeLinearScanOrder::compute_order(BlockBegin* start_block) { 842 TRACE_LINEAR_SCAN(3, "----- computing final block order"); 843 844 // the start block is always the first block in the linear scan order 845 _linear_scan_order = new BlockList(_num_blocks); 846 append_block(start_block); 847 848 assert(start_block->end()->as_Base() != NULL, "start block must end with Base-instruction"); 849 BlockBegin* std_entry = ((Base*)start_block->end())->std_entry(); 850 BlockBegin* osr_entry = ((Base*)start_block->end())->osr_entry(); 851 852 BlockBegin* sux_of_osr_entry = NULL; 853 if (osr_entry != NULL) { 854 // special handling for osr entry: 855 // ignore the edge between the osr entry and its successor for processing 856 // the osr entry block is added manually below 857 assert(osr_entry->number_of_sux() == 1, "osr entry must have exactly one successor"); 858 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"); 859 860 sux_of_osr_entry = osr_entry->sux_at(0); 861 dec_forward_branches(sux_of_osr_entry); 862 863 compute_dominator(osr_entry, start_block); 864 _iterative_dominators = true; 865 } 866 compute_dominator(std_entry, start_block); 867 868 // start processing with standard entry block 869 assert(_work_list.is_empty(), "list must be empty before processing"); 870 871 if (ready_for_processing(std_entry)) { 872 sort_into_work_list(std_entry); 873 } else { 874 assert(false, "the std_entry must be ready for processing (otherwise, the method has no start block)"); 875 } 876 877 do { 878 BlockBegin* cur = _work_list.pop(); 879 880 if (cur == sux_of_osr_entry) { 881 // the osr entry block is ignored in normal processing, it is never added to the 882 // work list. Instead, it is added as late as possible manually here. 883 append_block(osr_entry); 884 compute_dominator(cur, osr_entry); 885 } 886 append_block(cur); 887 888 int i; 889 int num_sux = cur->number_of_sux(); 890 // changed loop order to get "intuitive" order of if- and else-blocks 891 for (i = 0; i < num_sux; i++) { 892 BlockBegin* sux = cur->sux_at(i); 893 compute_dominator(sux, cur); 894 if (ready_for_processing(sux)) { 895 sort_into_work_list(sux); 896 } 897 } 898 num_sux = cur->number_of_exception_handlers(); 899 for (i = 0; i < num_sux; i++) { 900 BlockBegin* sux = cur->exception_handler_at(i); 901 compute_dominator(sux, cur); 902 if (ready_for_processing(sux)) { 903 sort_into_work_list(sux); 904 } 905 } 906 } while (_work_list.length() > 0); 907 } 908 909 910 bool ComputeLinearScanOrder::compute_dominators_iter() { 911 bool changed = false; 912 int num_blocks = _linear_scan_order->length(); 913 914 assert(_linear_scan_order->at(0)->dominator() == NULL, "must not have dominator"); 915 assert(_linear_scan_order->at(0)->number_of_preds() == 0, "must not have predecessors"); 916 for (int i = 1; i < num_blocks; i++) { 917 BlockBegin* block = _linear_scan_order->at(i); 918 919 BlockBegin* dominator = block->pred_at(0); 920 int num_preds = block->number_of_preds(); 921 for (int i = 1; i < num_preds; i++) { 922 dominator = common_dominator(dominator, block->pred_at(i)); 923 } 924 925 if (dominator != block->dominator()) { 926 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())); 927 928 block->set_dominator(dominator); 929 changed = true; 930 } 931 } 932 return changed; 933 } 934 935 void ComputeLinearScanOrder::compute_dominators() { 936 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing dominators (iterative computation reqired: %d)", _iterative_dominators)); 937 938 // iterative computation of dominators is only required for methods with non-natural loops 939 // and OSR-methods. For all other methods, the dominators computed when generating the 940 // linear scan block order are correct. 941 if (_iterative_dominators) { 942 do { 943 TRACE_LINEAR_SCAN(1, tty->print_cr("DOM: next iteration of fix-point calculation")); 944 } while (compute_dominators_iter()); 945 } 946 947 // check that dominators are correct 948 assert(!compute_dominators_iter(), "fix point not reached"); 949 } 950 951 952 #ifndef PRODUCT 953 void ComputeLinearScanOrder::print_blocks() { 954 if (TraceLinearScanLevel >= 2) { 955 tty->print_cr("----- loop information:"); 956 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { 957 BlockBegin* cur = _linear_scan_order->at(block_idx); 958 959 tty->print("%4d: B%2d: ", cur->linear_scan_number(), cur->block_id()); 960 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { 961 tty->print ("%d ", is_block_in_loop(loop_idx, cur)); 962 } 963 tty->print_cr(" -> loop_index: %2d, loop_depth: %2d", cur->loop_index(), cur->loop_depth()); 964 } 965 } 966 967 if (TraceLinearScanLevel >= 1) { 968 tty->print_cr("----- linear-scan block order:"); 969 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { 970 BlockBegin* cur = _linear_scan_order->at(block_idx); 971 tty->print("%4d: B%2d loop: %2d depth: %2d", cur->linear_scan_number(), cur->block_id(), cur->loop_index(), cur->loop_depth()); 972 973 tty->print(cur->is_set(BlockBegin::exception_entry_flag) ? " ex" : " "); 974 tty->print(cur->is_set(BlockBegin::critical_edge_split_flag) ? " ce" : " "); 975 tty->print(cur->is_set(BlockBegin::linear_scan_loop_header_flag) ? " lh" : " "); 976 tty->print(cur->is_set(BlockBegin::linear_scan_loop_end_flag) ? " le" : " "); 977 978 if (cur->dominator() != NULL) { 979 tty->print(" dom: B%d ", cur->dominator()->block_id()); 980 } else { 981 tty->print(" dom: NULL "); 982 } 983 984 if (cur->number_of_preds() > 0) { 985 tty->print(" preds: "); 986 for (int j = 0; j < cur->number_of_preds(); j++) { 987 BlockBegin* pred = cur->pred_at(j); 988 tty->print("B%d ", pred->block_id()); 989 } 990 } 991 if (cur->number_of_sux() > 0) { 992 tty->print(" sux: "); 993 for (int j = 0; j < cur->number_of_sux(); j++) { 994 BlockBegin* sux = cur->sux_at(j); 995 tty->print("B%d ", sux->block_id()); 996 } 997 } 998 if (cur->number_of_exception_handlers() > 0) { 999 tty->print(" ex: "); 1000 for (int j = 0; j < cur->number_of_exception_handlers(); j++) { 1001 BlockBegin* ex = cur->exception_handler_at(j); 1002 tty->print("B%d ", ex->block_id()); 1003 } 1004 } 1005 tty->cr(); 1006 } 1007 } 1008 } 1009 #endif 1010 1011 #ifdef ASSERT 1012 void ComputeLinearScanOrder::verify() { 1013 assert(_linear_scan_order->length() == _num_blocks, "wrong number of blocks in list"); 1014 1015 if (StressLinearScan) { 1016 // blocks are scrambled when StressLinearScan is used 1017 return; 1018 } 1019 1020 // check that all successors of a block have a higher linear-scan-number 1021 // and that all predecessors of a block have a lower linear-scan-number 1022 // (only backward branches of loops are ignored) 1023 int i; 1024 for (i = 0; i < _linear_scan_order->length(); i++) { 1025 BlockBegin* cur = _linear_scan_order->at(i); 1026 1027 assert(cur->linear_scan_number() == i, "incorrect linear_scan_number"); 1028 assert(cur->linear_scan_number() >= 0 && cur->linear_scan_number() == _linear_scan_order->index_of(cur), "incorrect linear_scan_number"); 1029 1030 int j; 1031 for (j = cur->number_of_sux() - 1; j >= 0; j--) { 1032 BlockBegin* sux = cur->sux_at(j); 1033 1034 assert(sux->linear_scan_number() >= 0 && sux->linear_scan_number() == _linear_scan_order->index_of(sux), "incorrect linear_scan_number"); 1035 if (!cur->is_set(BlockBegin::linear_scan_loop_end_flag)) { 1036 assert(cur->linear_scan_number() < sux->linear_scan_number(), "invalid order"); 1037 } 1038 if (cur->loop_depth() == sux->loop_depth()) { 1039 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"); 1040 } 1041 } 1042 1043 for (j = cur->number_of_preds() - 1; j >= 0; j--) { 1044 BlockBegin* pred = cur->pred_at(j); 1045 1046 assert(pred->linear_scan_number() >= 0 && pred->linear_scan_number() == _linear_scan_order->index_of(pred), "incorrect linear_scan_number"); 1047 if (!cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { 1048 assert(cur->linear_scan_number() > pred->linear_scan_number(), "invalid order"); 1049 } 1050 if (cur->loop_depth() == pred->loop_depth()) { 1051 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"); 1052 } 1053 1054 assert(cur->dominator()->linear_scan_number() <= cur->pred_at(j)->linear_scan_number(), "dominator must be before predecessors"); 1055 } 1056 1057 // check dominator 1058 if (i == 0) { 1059 assert(cur->dominator() == NULL, "first block has no dominator"); 1060 } else { 1061 assert(cur->dominator() != NULL, "all but first block must have dominator"); 1062 } 1063 assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0), "Single predecessor must also be dominator"); 1064 } 1065 1066 // check that all loops are continuous 1067 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { 1068 int block_idx = 0; 1069 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "the first block must not be present in any loop"); 1070 1071 // skip blocks before the loop 1072 while (block_idx < _num_blocks && !is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { 1073 block_idx++; 1074 } 1075 // skip blocks of loop 1076 while (block_idx < _num_blocks && is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { 1077 block_idx++; 1078 } 1079 // after the first non-loop block, there must not be another loop-block 1080 while (block_idx < _num_blocks) { 1081 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "loop not continuous in linear-scan order"); 1082 block_idx++; 1083 } 1084 } 1085 } 1086 #endif 1087 1088 1089 void IR::compute_code() { 1090 assert(is_valid(), "IR must be valid"); 1091 1092 ComputeLinearScanOrder compute_order(compilation(), start()); 1093 _num_loops = compute_order.num_loops(); 1094 _code = compute_order.linear_scan_order(); 1095 } 1096 1097 1098 void IR::compute_use_counts() { 1099 // make sure all values coming out of this block get evaluated. 1100 int num_blocks = _code->length(); 1101 for (int i = 0; i < num_blocks; i++) { 1102 _code->at(i)->end()->state()->pin_stack_for_linear_scan(); 1103 } 1104 1105 // compute use counts 1106 UseCountComputer::compute(_code); 1107 } 1108 1109 1110 void IR::iterate_preorder(BlockClosure* closure) { 1111 assert(is_valid(), "IR must be valid"); 1112 start()->iterate_preorder(closure); 1113 } 1114 1115 1116 void IR::iterate_postorder(BlockClosure* closure) { 1117 assert(is_valid(), "IR must be valid"); 1118 start()->iterate_postorder(closure); 1119 } 1120 1121 void IR::iterate_linear_scan_order(BlockClosure* closure) { 1122 linear_scan_order()->iterate_forward(closure); 1123 } 1124 1125 1126 #ifndef PRODUCT 1127 class BlockPrinter: public BlockClosure { 1128 private: 1129 InstructionPrinter* _ip; 1130 bool _cfg_only; 1131 bool _live_only; 1132 1133 public: 1134 BlockPrinter(InstructionPrinter* ip, bool cfg_only, bool live_only = false) { 1135 _ip = ip; 1136 _cfg_only = cfg_only; 1137 _live_only = live_only; 1138 } 1139 1140 virtual void block_do(BlockBegin* block) { 1141 if (_cfg_only) { 1142 _ip->print_instr(block); tty->cr(); 1143 } else { 1144 block->print_block(*_ip, _live_only); 1145 } 1146 } 1147 }; 1148 1149 1150 void IR::print(BlockBegin* start, bool cfg_only, bool live_only) { 1151 ttyLocker ttyl; 1152 InstructionPrinter ip(!cfg_only); 1153 BlockPrinter bp(&ip, cfg_only, live_only); 1154 start->iterate_preorder(&bp); 1155 tty->cr(); 1156 } 1157 1158 void IR::print(bool cfg_only, bool live_only) { 1159 if (is_valid()) { 1160 print(start(), cfg_only, live_only); 1161 } else { 1162 tty->print_cr("invalid IR"); 1163 } 1164 } 1165 1166 1167 define_array(BlockListArray, BlockList*) 1168 define_stack(BlockListList, BlockListArray) 1169 1170 class PredecessorValidator : public BlockClosure { 1171 private: 1172 BlockListList* _predecessors; 1173 BlockList* _blocks; 1174 1175 static int cmp(BlockBegin** a, BlockBegin** b) { 1176 return (*a)->block_id() - (*b)->block_id(); 1177 } 1178 1179 public: 1180 PredecessorValidator(IR* hir) { 1181 ResourceMark rm; 1182 _predecessors = new BlockListList(BlockBegin::number_of_blocks(), NULL); 1183 _blocks = new BlockList(); 1184 1185 int i; 1186 hir->start()->iterate_preorder(this); 1187 if (hir->code() != NULL) { 1188 assert(hir->code()->length() == _blocks->length(), "must match"); 1189 for (i = 0; i < _blocks->length(); i++) { 1190 assert(hir->code()->contains(_blocks->at(i)), "should be in both lists"); 1191 } 1192 } 1193 1194 for (i = 0; i < _blocks->length(); i++) { 1195 BlockBegin* block = _blocks->at(i); 1196 BlockList* preds = _predecessors->at(block->block_id()); 1197 if (preds == NULL) { 1198 assert(block->number_of_preds() == 0, "should be the same"); 1199 continue; 1200 } 1201 1202 // clone the pred list so we can mutate it 1203 BlockList* pred_copy = new BlockList(); 1204 int j; 1205 for (j = 0; j < block->number_of_preds(); j++) { 1206 pred_copy->append(block->pred_at(j)); 1207 } 1208 // sort them in the same order 1209 preds->sort(cmp); 1210 pred_copy->sort(cmp); 1211 int length = MIN2(preds->length(), block->number_of_preds()); 1212 for (j = 0; j < block->number_of_preds(); j++) { 1213 assert(preds->at(j) == pred_copy->at(j), "must match"); 1214 } 1215 1216 assert(preds->length() == block->number_of_preds(), "should be the same"); 1217 } 1218 } 1219 1220 virtual void block_do(BlockBegin* block) { 1221 _blocks->append(block); 1222 BlockEnd* be = block->end(); 1223 int n = be->number_of_sux(); 1224 int i; 1225 for (i = 0; i < n; i++) { 1226 BlockBegin* sux = be->sux_at(i); 1227 assert(!sux->is_set(BlockBegin::exception_entry_flag), "must not be xhandler"); 1228 1229 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); 1230 if (preds == NULL) { 1231 preds = new BlockList(); 1232 _predecessors->at_put(sux->block_id(), preds); 1233 } 1234 preds->append(block); 1235 } 1236 1237 n = block->number_of_exception_handlers(); 1238 for (i = 0; i < n; i++) { 1239 BlockBegin* sux = block->exception_handler_at(i); 1240 assert(sux->is_set(BlockBegin::exception_entry_flag), "must be xhandler"); 1241 1242 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); 1243 if (preds == NULL) { 1244 preds = new BlockList(); 1245 _predecessors->at_put(sux->block_id(), preds); 1246 } 1247 preds->append(block); 1248 } 1249 } 1250 }; 1251 1252 void IR::verify() { 1253 #ifdef ASSERT 1254 PredecessorValidator pv(this); 1255 #endif 1256 } 1257 1258 #endif // PRODUCT 1259 1260 void SubstitutionResolver::visit(Value* v) { 1261 Value v0 = *v; 1262 if (v0) { 1263 Value vs = v0->subst(); 1264 if (vs != v0) { 1265 *v = v0->subst(); 1266 } 1267 } 1268 } 1269 1270 #ifdef ASSERT 1271 class SubstitutionChecker: public ValueVisitor { 1272 void visit(Value* v) { 1273 Value v0 = *v; 1274 if (v0) { 1275 Value vs = v0->subst(); 1276 assert(vs == v0, "missed substitution"); 1277 } 1278 } 1279 }; 1280 #endif 1281 1282 1283 void SubstitutionResolver::block_do(BlockBegin* block) { 1284 Instruction* last = NULL; 1285 for (Instruction* n = block; n != NULL;) { 1286 n->values_do(this); 1287 // need to remove this instruction from the instruction stream 1288 if (n->subst() != n) { 1289 assert(last != NULL, "must have last"); 1290 last->set_next(n->next()); 1291 } else { 1292 last = n; 1293 } 1294 n = last->next(); 1295 } 1296 1297 #ifdef ASSERT 1298 SubstitutionChecker check_substitute; 1299 if (block->state()) block->state()->values_do(&check_substitute); 1300 block->block_values_do(&check_substitute); 1301 if (block->end() && block->end()->state()) block->end()->state()->values_do(&check_substitute); 1302 #endif 1303 }