1 /* 2 * Copyright (c) 1997, 2013, 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 "memory/allocation.inline.hpp" 27 #include "opto/block.hpp" 28 #include "opto/callnode.hpp" 29 #include "opto/cfgnode.hpp" 30 #include "opto/connode.hpp" 31 #include "opto/idealGraphPrinter.hpp" 32 #include "opto/loopnode.hpp" 33 #include "opto/machnode.hpp" 34 #include "opto/opcodes.hpp" 35 #include "opto/phaseX.hpp" 36 #include "opto/regalloc.hpp" 37 #include "opto/rootnode.hpp" 38 39 //============================================================================= 40 #define NODE_HASH_MINIMUM_SIZE 255 41 //------------------------------NodeHash--------------------------------------- 42 NodeHash::NodeHash(uint est_max_size) : 43 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ), 44 _a(Thread::current()->resource_area()), 45 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ), 46 _inserts(0), _insert_limit( insert_limit() ), 47 _look_probes(0), _lookup_hits(0), _lookup_misses(0), 48 _total_insert_probes(0), _total_inserts(0), 49 _insert_probes(0), _grows(0) { 50 // _sentinel must be in the current node space 51 _sentinel = new (Compile::current()) ProjNode(NULL, TypeFunc::Control); 52 memset(_table,0,sizeof(Node*)*_max); 53 } 54 55 //------------------------------NodeHash--------------------------------------- 56 NodeHash::NodeHash(Arena *arena, uint est_max_size) : 57 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ), 58 _a(arena), 59 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), 60 _inserts(0), _insert_limit( insert_limit() ), 61 _look_probes(0), _lookup_hits(0), _lookup_misses(0), 62 _delete_probes(0), _delete_hits(0), _delete_misses(0), 63 _total_insert_probes(0), _total_inserts(0), 64 _insert_probes(0), _grows(0) { 65 // _sentinel must be in the current node space 66 _sentinel = new (Compile::current()) ProjNode(NULL, TypeFunc::Control); 67 memset(_table,0,sizeof(Node*)*_max); 68 } 69 70 //------------------------------NodeHash--------------------------------------- 71 NodeHash::NodeHash(NodeHash *nh) { 72 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator= 73 // just copy in all the fields 74 *this = *nh; 75 // nh->_sentinel must be in the current node space 76 } 77 78 void NodeHash::replace_with(NodeHash *nh) { 79 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator= 80 // just copy in all the fields 81 *this = *nh; 82 // nh->_sentinel must be in the current node space 83 } 84 85 //------------------------------hash_find-------------------------------------- 86 // Find in hash table 87 Node *NodeHash::hash_find( const Node *n ) { 88 // ((Node*)n)->set_hash( n->hash() ); 89 uint hash = n->hash(); 90 if (hash == Node::NO_HASH) { 91 debug_only( _lookup_misses++ ); 92 return NULL; 93 } 94 uint key = hash & (_max-1); 95 uint stride = key | 0x01; 96 debug_only( _look_probes++ ); 97 Node *k = _table[key]; // Get hashed value 98 if( !k ) { // ?Miss? 99 debug_only( _lookup_misses++ ); 100 return NULL; // Miss! 101 } 102 103 int op = n->Opcode(); 104 uint req = n->req(); 105 while( 1 ) { // While probing hash table 106 if( k->req() == req && // Same count of inputs 107 k->Opcode() == op ) { // Same Opcode 108 for( uint i=0; i<req; i++ ) 109 if( n->in(i)!=k->in(i)) // Different inputs? 110 goto collision; // "goto" is a speed hack... 111 if( n->cmp(*k) ) { // Check for any special bits 112 debug_only( _lookup_hits++ ); 113 return k; // Hit! 114 } 115 } 116 collision: 117 debug_only( _look_probes++ ); 118 key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime 119 k = _table[key]; // Get hashed value 120 if( !k ) { // ?Miss? 121 debug_only( _lookup_misses++ ); 122 return NULL; // Miss! 123 } 124 } 125 ShouldNotReachHere(); 126 return NULL; 127 } 128 129 //------------------------------hash_find_insert------------------------------- 130 // Find in hash table, insert if not already present 131 // Used to preserve unique entries in hash table 132 Node *NodeHash::hash_find_insert( Node *n ) { 133 // n->set_hash( ); 134 uint hash = n->hash(); 135 if (hash == Node::NO_HASH) { 136 debug_only( _lookup_misses++ ); 137 return NULL; 138 } 139 uint key = hash & (_max-1); 140 uint stride = key | 0x01; // stride must be relatively prime to table siz 141 uint first_sentinel = 0; // replace a sentinel if seen. 142 debug_only( _look_probes++ ); 143 Node *k = _table[key]; // Get hashed value 144 if( !k ) { // ?Miss? 145 debug_only( _lookup_misses++ ); 146 _table[key] = n; // Insert into table! 147 debug_only(n->enter_hash_lock()); // Lock down the node while in the table. 148 check_grow(); // Grow table if insert hit limit 149 return NULL; // Miss! 150 } 151 else if( k == _sentinel ) { 152 first_sentinel = key; // Can insert here 153 } 154 155 int op = n->Opcode(); 156 uint req = n->req(); 157 while( 1 ) { // While probing hash table 158 if( k->req() == req && // Same count of inputs 159 k->Opcode() == op ) { // Same Opcode 160 for( uint i=0; i<req; i++ ) 161 if( n->in(i)!=k->in(i)) // Different inputs? 162 goto collision; // "goto" is a speed hack... 163 if( n->cmp(*k) ) { // Check for any special bits 164 debug_only( _lookup_hits++ ); 165 return k; // Hit! 166 } 167 } 168 collision: 169 debug_only( _look_probes++ ); 170 key = (key + stride) & (_max-1); // Stride through table w/ relative prime 171 k = _table[key]; // Get hashed value 172 if( !k ) { // ?Miss? 173 debug_only( _lookup_misses++ ); 174 key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel? 175 _table[key] = n; // Insert into table! 176 debug_only(n->enter_hash_lock()); // Lock down the node while in the table. 177 check_grow(); // Grow table if insert hit limit 178 return NULL; // Miss! 179 } 180 else if( first_sentinel == 0 && k == _sentinel ) { 181 first_sentinel = key; // Can insert here 182 } 183 184 } 185 ShouldNotReachHere(); 186 return NULL; 187 } 188 189 //------------------------------hash_insert------------------------------------ 190 // Insert into hash table 191 void NodeHash::hash_insert( Node *n ) { 192 // // "conflict" comments -- print nodes that conflict 193 // bool conflict = false; 194 // n->set_hash(); 195 uint hash = n->hash(); 196 if (hash == Node::NO_HASH) { 197 return; 198 } 199 check_grow(); 200 uint key = hash & (_max-1); 201 uint stride = key | 0x01; 202 203 while( 1 ) { // While probing hash table 204 debug_only( _insert_probes++ ); 205 Node *k = _table[key]; // Get hashed value 206 if( !k || (k == _sentinel) ) break; // Found a slot 207 assert( k != n, "already inserted" ); 208 // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; } 209 key = (key + stride) & (_max-1); // Stride through table w/ relative prime 210 } 211 _table[key] = n; // Insert into table! 212 debug_only(n->enter_hash_lock()); // Lock down the node while in the table. 213 // if( conflict ) { n->dump(); } 214 } 215 216 //------------------------------hash_delete------------------------------------ 217 // Replace in hash table with sentinel 218 bool NodeHash::hash_delete( const Node *n ) { 219 Node *k; 220 uint hash = n->hash(); 221 if (hash == Node::NO_HASH) { 222 debug_only( _delete_misses++ ); 223 return false; 224 } 225 uint key = hash & (_max-1); 226 uint stride = key | 0x01; 227 debug_only( uint counter = 0; ); 228 for( ; /* (k != NULL) && (k != _sentinel) */; ) { 229 debug_only( counter++ ); 230 debug_only( _delete_probes++ ); 231 k = _table[key]; // Get hashed value 232 if( !k ) { // Miss? 233 debug_only( _delete_misses++ ); 234 #ifdef ASSERT 235 if( VerifyOpto ) { 236 for( uint i=0; i < _max; i++ ) 237 assert( _table[i] != n, "changed edges with rehashing" ); 238 } 239 #endif 240 return false; // Miss! Not in chain 241 } 242 else if( n == k ) { 243 debug_only( _delete_hits++ ); 244 _table[key] = _sentinel; // Hit! Label as deleted entry 245 debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table. 246 return true; 247 } 248 else { 249 // collision: move through table with prime offset 250 key = (key + stride/*7*/) & (_max-1); 251 assert( counter <= _insert_limit, "Cycle in hash-table"); 252 } 253 } 254 ShouldNotReachHere(); 255 return false; 256 } 257 258 //------------------------------round_up--------------------------------------- 259 // Round up to nearest power of 2 260 uint NodeHash::round_up( uint x ) { 261 x += (x>>2); // Add 25% slop 262 if( x <16 ) return 16; // Small stuff 263 uint i=16; 264 while( i < x ) i <<= 1; // Double to fit 265 return i; // Return hash table size 266 } 267 268 //------------------------------grow------------------------------------------- 269 // Grow _table to next power of 2 and insert old entries 270 void NodeHash::grow() { 271 // Record old state 272 uint old_max = _max; 273 Node **old_table = _table; 274 // Construct new table with twice the space 275 _grows++; 276 _total_inserts += _inserts; 277 _total_insert_probes += _insert_probes; 278 _inserts = 0; 279 _insert_probes = 0; 280 _max = _max << 1; 281 _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) ); 282 memset(_table,0,sizeof(Node*)*_max); 283 _insert_limit = insert_limit(); 284 // Insert old entries into the new table 285 for( uint i = 0; i < old_max; i++ ) { 286 Node *m = *old_table++; 287 if( !m || m == _sentinel ) continue; 288 debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table. 289 hash_insert(m); 290 } 291 } 292 293 //------------------------------clear------------------------------------------ 294 // Clear all entries in _table to NULL but keep storage 295 void NodeHash::clear() { 296 #ifdef ASSERT 297 // Unlock all nodes upon removal from table. 298 for (uint i = 0; i < _max; i++) { 299 Node* n = _table[i]; 300 if (!n || n == _sentinel) continue; 301 n->exit_hash_lock(); 302 } 303 #endif 304 305 memset( _table, 0, _max * sizeof(Node*) ); 306 } 307 308 //-----------------------remove_useless_nodes---------------------------------- 309 // Remove useless nodes from value table, 310 // implementation does not depend on hash function 311 void NodeHash::remove_useless_nodes(VectorSet &useful) { 312 313 // Dead nodes in the hash table inherited from GVN should not replace 314 // existing nodes, remove dead nodes. 315 uint max = size(); 316 Node *sentinel_node = sentinel(); 317 for( uint i = 0; i < max; ++i ) { 318 Node *n = at(i); 319 if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) { 320 debug_only(n->exit_hash_lock()); // Unlock the node when removed 321 _table[i] = sentinel_node; // Replace with placeholder 322 } 323 } 324 } 325 326 327 void NodeHash::check_no_speculative_types() { 328 #ifdef ASSERT 329 uint max = size(); 330 Node *sentinel_node = sentinel(); 331 for (uint i = 0; i < max; ++i) { 332 Node *n = at(i); 333 if(n != NULL && n != sentinel_node && n->is_Type() && n->outcnt() > 0) { 334 TypeNode* tn = n->as_Type(); 335 const Type* t = tn->type(); 336 const Type* t_no_spec = t->remove_speculative(); 337 assert(t == t_no_spec, "dead node in hash table or missed node during speculative cleanup"); 338 } 339 } 340 #endif 341 } 342 343 #ifndef PRODUCT 344 //------------------------------dump------------------------------------------- 345 // Dump statistics for the hash table 346 void NodeHash::dump() { 347 _total_inserts += _inserts; 348 _total_insert_probes += _insert_probes; 349 if (PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0)) { 350 if (WizardMode) { 351 for (uint i=0; i<_max; i++) { 352 if (_table[i]) 353 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx); 354 } 355 } 356 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max); 357 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0); 358 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses)); 359 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts); 360 // sentinels increase lookup cost, but not insert cost 361 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function"); 362 assert( _inserts+(_inserts>>3) < _max, "table too full" ); 363 assert( _inserts*3+100 >= _insert_probes, "bad hash function" ); 364 } 365 } 366 367 Node *NodeHash::find_index(uint idx) { // For debugging 368 // Find an entry by its index value 369 for( uint i = 0; i < _max; i++ ) { 370 Node *m = _table[i]; 371 if( !m || m == _sentinel ) continue; 372 if( m->_idx == (uint)idx ) return m; 373 } 374 return NULL; 375 } 376 #endif 377 378 #ifdef ASSERT 379 NodeHash::~NodeHash() { 380 // Unlock all nodes upon destruction of table. 381 if (_table != (Node**)badAddress) clear(); 382 } 383 384 void NodeHash::operator=(const NodeHash& nh) { 385 // Unlock all nodes upon replacement of table. 386 if (&nh == this) return; 387 if (_table != (Node**)badAddress) clear(); 388 memcpy(this, &nh, sizeof(*this)); 389 // Do not increment hash_lock counts again. 390 // Instead, be sure we never again use the source table. 391 ((NodeHash*)&nh)->_table = (Node**)badAddress; 392 } 393 394 395 #endif 396 397 398 //============================================================================= 399 //------------------------------PhaseRemoveUseless----------------------------- 400 // 1) Use a breadthfirst walk to collect useful nodes reachable from root. 401 PhaseRemoveUseless::PhaseRemoveUseless( PhaseGVN *gvn, Unique_Node_List *worklist ) : Phase(Remove_Useless), 402 _useful(Thread::current()->resource_area()) { 403 404 // Implementation requires 'UseLoopSafepoints == true' and an edge from root 405 // to each SafePointNode at a backward branch. Inserted in add_safepoint(). 406 if( !UseLoopSafepoints || !OptoRemoveUseless ) return; 407 408 // Identify nodes that are reachable from below, useful. 409 C->identify_useful_nodes(_useful); 410 // Update dead node list 411 C->update_dead_node_list(_useful); 412 413 // Remove all useless nodes from PhaseValues' recorded types 414 // Must be done before disconnecting nodes to preserve hash-table-invariant 415 gvn->remove_useless_nodes(_useful.member_set()); 416 417 // Remove all useless nodes from future worklist 418 worklist->remove_useless_nodes(_useful.member_set()); 419 420 // Disconnect 'useless' nodes that are adjacent to useful nodes 421 C->remove_useless_nodes(_useful); 422 423 // Remove edges from "root" to each SafePoint at a backward branch. 424 // They were inserted during parsing (see add_safepoint()) to make infinite 425 // loops without calls or exceptions visible to root, i.e., useful. 426 Node *root = C->root(); 427 if( root != NULL ) { 428 for( uint i = root->req(); i < root->len(); ++i ) { 429 Node *n = root->in(i); 430 if( n != NULL && n->is_SafePoint() ) { 431 root->rm_prec(i); 432 --i; 433 } 434 } 435 } 436 } 437 438 439 //============================================================================= 440 //------------------------------PhaseTransform--------------------------------- 441 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum), 442 _arena(Thread::current()->resource_area()), 443 _nodes(_arena), 444 _types(_arena) 445 { 446 init_con_caches(); 447 #ifndef PRODUCT 448 clear_progress(); 449 clear_transforms(); 450 set_allow_progress(true); 451 #endif 452 // Force allocation for currently existing nodes 453 _types.map(C->unique(), NULL); 454 } 455 456 //------------------------------PhaseTransform--------------------------------- 457 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum), 458 _arena(arena), 459 _nodes(arena), 460 _types(arena) 461 { 462 init_con_caches(); 463 #ifndef PRODUCT 464 clear_progress(); 465 clear_transforms(); 466 set_allow_progress(true); 467 #endif 468 // Force allocation for currently existing nodes 469 _types.map(C->unique(), NULL); 470 } 471 472 //------------------------------PhaseTransform--------------------------------- 473 // Initialize with previously generated type information 474 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum), 475 _arena(pt->_arena), 476 _nodes(pt->_nodes), 477 _types(pt->_types) 478 { 479 init_con_caches(); 480 #ifndef PRODUCT 481 clear_progress(); 482 clear_transforms(); 483 set_allow_progress(true); 484 #endif 485 } 486 487 void PhaseTransform::init_con_caches() { 488 memset(_icons,0,sizeof(_icons)); 489 memset(_lcons,0,sizeof(_lcons)); 490 memset(_zcons,0,sizeof(_zcons)); 491 } 492 493 494 //--------------------------------find_int_type-------------------------------- 495 const TypeInt* PhaseTransform::find_int_type(Node* n) { 496 if (n == NULL) return NULL; 497 // Call type_or_null(n) to determine node's type since we might be in 498 // parse phase and call n->Value() may return wrong type. 499 // (For example, a phi node at the beginning of loop parsing is not ready.) 500 const Type* t = type_or_null(n); 501 if (t == NULL) return NULL; 502 return t->isa_int(); 503 } 504 505 506 //-------------------------------find_long_type-------------------------------- 507 const TypeLong* PhaseTransform::find_long_type(Node* n) { 508 if (n == NULL) return NULL; 509 // (See comment above on type_or_null.) 510 const Type* t = type_or_null(n); 511 if (t == NULL) return NULL; 512 return t->isa_long(); 513 } 514 515 516 #ifndef PRODUCT 517 void PhaseTransform::dump_old2new_map() const { 518 _nodes.dump(); 519 } 520 521 void PhaseTransform::dump_new( uint nidx ) const { 522 for( uint i=0; i<_nodes.Size(); i++ ) 523 if( _nodes[i] && _nodes[i]->_idx == nidx ) { 524 _nodes[i]->dump(); 525 tty->cr(); 526 tty->print_cr("Old index= %d",i); 527 return; 528 } 529 tty->print_cr("Node %d not found in the new indices", nidx); 530 } 531 532 //------------------------------dump_types------------------------------------- 533 void PhaseTransform::dump_types( ) const { 534 _types.dump(); 535 } 536 537 //------------------------------dump_nodes_and_types--------------------------- 538 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) { 539 VectorSet visited(Thread::current()->resource_area()); 540 dump_nodes_and_types_recur( root, depth, only_ctrl, visited ); 541 } 542 543 //------------------------------dump_nodes_and_types_recur--------------------- 544 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) { 545 if( !n ) return; 546 if( depth == 0 ) return; 547 if( visited.test_set(n->_idx) ) return; 548 for( uint i=0; i<n->len(); i++ ) { 549 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue; 550 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited ); 551 } 552 n->dump(); 553 if (type_or_null(n) != NULL) { 554 tty->print(" "); type(n)->dump(); tty->cr(); 555 } 556 } 557 558 #endif 559 560 561 //============================================================================= 562 //------------------------------PhaseValues------------------------------------ 563 // Set minimum table size to "255" 564 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) { 565 NOT_PRODUCT( clear_new_values(); ) 566 } 567 568 //------------------------------PhaseValues------------------------------------ 569 // Set minimum table size to "255" 570 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ), 571 _table(&ptv->_table) { 572 NOT_PRODUCT( clear_new_values(); ) 573 } 574 575 //------------------------------PhaseValues------------------------------------ 576 // Used by +VerifyOpto. Clear out hash table but copy _types array. 577 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ), 578 _table(ptv->arena(),ptv->_table.size()) { 579 NOT_PRODUCT( clear_new_values(); ) 580 } 581 582 //------------------------------~PhaseValues----------------------------------- 583 #ifndef PRODUCT 584 PhaseValues::~PhaseValues() { 585 _table.dump(); 586 587 // Statistics for value progress and efficiency 588 if( PrintCompilation && Verbose && WizardMode ) { 589 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)", 590 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values()); 591 if( made_transforms() != 0 ) { 592 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() ); 593 } else { 594 tty->cr(); 595 } 596 } 597 } 598 #endif 599 600 //------------------------------makecon---------------------------------------- 601 ConNode* PhaseTransform::makecon(const Type *t) { 602 assert(t->singleton(), "must be a constant"); 603 assert(!t->empty() || t == Type::TOP, "must not be vacuous range"); 604 switch (t->base()) { // fast paths 605 case Type::Half: 606 case Type::Top: return (ConNode*) C->top(); 607 case Type::Int: return intcon( t->is_int()->get_con() ); 608 case Type::Long: return longcon( t->is_long()->get_con() ); 609 } 610 if (t->is_zero_type()) 611 return zerocon(t->basic_type()); 612 return uncached_makecon(t); 613 } 614 615 //--------------------------uncached_makecon----------------------------------- 616 // Make an idealized constant - one of ConINode, ConPNode, etc. 617 ConNode* PhaseValues::uncached_makecon(const Type *t) { 618 assert(t->singleton(), "must be a constant"); 619 ConNode* x = ConNode::make(C, t); 620 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering 621 if (k == NULL) { 622 set_type(x, t); // Missed, provide type mapping 623 GrowableArray<Node_Notes*>* nna = C->node_note_array(); 624 if (nna != NULL) { 625 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true); 626 loc->clear(); // do not put debug info on constants 627 } 628 } else { 629 x->destruct(); // Hit, destroy duplicate constant 630 x = k; // use existing constant 631 } 632 return x; 633 } 634 635 //------------------------------intcon----------------------------------------- 636 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))" 637 ConINode* PhaseTransform::intcon(int i) { 638 // Small integer? Check cache! Check that cached node is not dead 639 if (i >= _icon_min && i <= _icon_max) { 640 ConINode* icon = _icons[i-_icon_min]; 641 if (icon != NULL && icon->in(TypeFunc::Control) != NULL) 642 return icon; 643 } 644 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i)); 645 assert(icon->is_Con(), ""); 646 if (i >= _icon_min && i <= _icon_max) 647 _icons[i-_icon_min] = icon; // Cache small integers 648 return icon; 649 } 650 651 //------------------------------longcon---------------------------------------- 652 // Fast long constant. 653 ConLNode* PhaseTransform::longcon(jlong l) { 654 // Small integer? Check cache! Check that cached node is not dead 655 if (l >= _lcon_min && l <= _lcon_max) { 656 ConLNode* lcon = _lcons[l-_lcon_min]; 657 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL) 658 return lcon; 659 } 660 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l)); 661 assert(lcon->is_Con(), ""); 662 if (l >= _lcon_min && l <= _lcon_max) 663 _lcons[l-_lcon_min] = lcon; // Cache small integers 664 return lcon; 665 } 666 667 //------------------------------zerocon----------------------------------------- 668 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))" 669 ConNode* PhaseTransform::zerocon(BasicType bt) { 670 assert((uint)bt <= _zcon_max, "domain check"); 671 ConNode* zcon = _zcons[bt]; 672 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL) 673 return zcon; 674 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt)); 675 _zcons[bt] = zcon; 676 return zcon; 677 } 678 679 680 681 //============================================================================= 682 //------------------------------transform-------------------------------------- 683 // Return a node which computes the same function as this node, but in a 684 // faster or cheaper fashion. 685 Node *PhaseGVN::transform( Node *n ) { 686 return transform_no_reclaim(n); 687 } 688 689 //------------------------------transform-------------------------------------- 690 // Return a node which computes the same function as this node, but 691 // in a faster or cheaper fashion. 692 Node *PhaseGVN::transform_no_reclaim( Node *n ) { 693 NOT_PRODUCT( set_transforms(); ) 694 695 // Apply the Ideal call in a loop until it no longer applies 696 Node *k = n; 697 NOT_PRODUCT( uint loop_count = 0; ) 698 while( 1 ) { 699 Node *i = k->Ideal(this, /*can_reshape=*/false); 700 if( !i ) break; 701 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" ); 702 k = i; 703 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform"); 704 } 705 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } ) 706 707 708 // If brand new node, make space in type array. 709 ensure_type_or_null(k); 710 711 // Since I just called 'Value' to compute the set of run-time values 712 // for this Node, and 'Value' is non-local (and therefore expensive) I'll 713 // cache Value. Later requests for the local phase->type of this Node can 714 // use the cached Value instead of suffering with 'bottom_type'. 715 const Type *t = k->Value(this); // Get runtime Value set 716 assert(t != NULL, "value sanity"); 717 if (type_or_null(k) != t) { 718 #ifndef PRODUCT 719 // Do not count initial visit to node as a transformation 720 if (type_or_null(k) == NULL) { 721 inc_new_values(); 722 set_progress(); 723 } 724 #endif 725 set_type(k, t); 726 // If k is a TypeNode, capture any more-precise type permanently into Node 727 k->raise_bottom_type(t); 728 } 729 730 if( t->singleton() && !k->is_Con() ) { 731 NOT_PRODUCT( set_progress(); ) 732 return makecon(t); // Turn into a constant 733 } 734 735 // Now check for Identities 736 Node *i = k->Identity(this); // Look for a nearby replacement 737 if( i != k ) { // Found? Return replacement! 738 NOT_PRODUCT( set_progress(); ) 739 return i; 740 } 741 742 // Global Value Numbering 743 i = hash_find_insert(k); // Insert if new 744 if( i && (i != k) ) { 745 // Return the pre-existing node 746 NOT_PRODUCT( set_progress(); ) 747 return i; 748 } 749 750 // Return Idealized original 751 return k; 752 } 753 754 #ifdef ASSERT 755 //------------------------------dead_loop_check-------------------------------- 756 // Check for a simple dead loop when a data node references itself directly 757 // or through an other data node excluding cons and phis. 758 void PhaseGVN::dead_loop_check( Node *n ) { 759 // Phi may reference itself in a loop 760 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) { 761 // Do 2 levels check and only data inputs. 762 bool no_dead_loop = true; 763 uint cnt = n->req(); 764 for (uint i = 1; i < cnt && no_dead_loop; i++) { 765 Node *in = n->in(i); 766 if (in == n) { 767 no_dead_loop = false; 768 } else if (in != NULL && !in->is_dead_loop_safe()) { 769 uint icnt = in->req(); 770 for (uint j = 1; j < icnt && no_dead_loop; j++) { 771 if (in->in(j) == n || in->in(j) == in) 772 no_dead_loop = false; 773 } 774 } 775 } 776 if (!no_dead_loop) n->dump(3); 777 assert(no_dead_loop, "dead loop detected"); 778 } 779 } 780 #endif 781 782 //============================================================================= 783 //------------------------------PhaseIterGVN----------------------------------- 784 // Initialize hash table to fresh and clean for +VerifyOpto 785 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ), 786 _stack(C->unique() >> 1), 787 _delay_transform(false) { 788 } 789 790 //------------------------------PhaseIterGVN----------------------------------- 791 // Initialize with previous PhaseIterGVN info; used by PhaseCCP 792 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn), 793 _worklist( igvn->_worklist ), 794 _stack( igvn->_stack ), 795 _delay_transform(igvn->_delay_transform) 796 { 797 } 798 799 //------------------------------PhaseIterGVN----------------------------------- 800 // Initialize with previous PhaseGVN info from Parser 801 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn), 802 _worklist(*C->for_igvn()), 803 _stack(C->unique() >> 1), 804 _delay_transform(false) 805 { 806 uint max; 807 808 // Dead nodes in the hash table inherited from GVN were not treated as 809 // roots during def-use info creation; hence they represent an invisible 810 // use. Clear them out. 811 max = _table.size(); 812 for( uint i = 0; i < max; ++i ) { 813 Node *n = _table.at(i); 814 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) { 815 if( n->is_top() ) continue; 816 assert( false, "Parse::remove_useless_nodes missed this node"); 817 hash_delete(n); 818 } 819 } 820 821 // Any Phis or Regions on the worklist probably had uses that could not 822 // make more progress because the uses were made while the Phis and Regions 823 // were in half-built states. Put all uses of Phis and Regions on worklist. 824 max = _worklist.size(); 825 for( uint j = 0; j < max; j++ ) { 826 Node *n = _worklist.at(j); 827 uint uop = n->Opcode(); 828 if( uop == Op_Phi || uop == Op_Region || 829 n->is_Type() || 830 n->is_Mem() ) 831 add_users_to_worklist(n); 832 } 833 } 834 835 836 #ifndef PRODUCT 837 void PhaseIterGVN::verify_step(Node* n) { 838 _verify_window[_verify_counter % _verify_window_size] = n; 839 ++_verify_counter; 840 ResourceMark rm; 841 ResourceArea *area = Thread::current()->resource_area(); 842 VectorSet old_space(area), new_space(area); 843 if (C->unique() < 1000 || 844 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) { 845 ++_verify_full_passes; 846 Node::verify_recur(C->root(), -1, old_space, new_space); 847 } 848 const int verify_depth = 4; 849 for ( int i = 0; i < _verify_window_size; i++ ) { 850 Node* n = _verify_window[i]; 851 if ( n == NULL ) continue; 852 if( n->in(0) == NodeSentinel ) { // xform_idom 853 _verify_window[i] = n->in(1); 854 --i; continue; 855 } 856 // Typical fanout is 1-2, so this call visits about 6 nodes. 857 Node::verify_recur(n, verify_depth, old_space, new_space); 858 } 859 } 860 #endif 861 862 863 //------------------------------init_worklist---------------------------------- 864 // Initialize worklist for each node. 865 void PhaseIterGVN::init_worklist( Node *n ) { 866 if( _worklist.member(n) ) return; 867 _worklist.push(n); 868 uint cnt = n->req(); 869 for( uint i =0 ; i < cnt; i++ ) { 870 Node *m = n->in(i); 871 if( m ) init_worklist(m); 872 } 873 } 874 875 //------------------------------optimize--------------------------------------- 876 void PhaseIterGVN::optimize() { 877 debug_only(uint num_processed = 0;); 878 #ifndef PRODUCT 879 { 880 _verify_counter = 0; 881 _verify_full_passes = 0; 882 for ( int i = 0; i < _verify_window_size; i++ ) { 883 _verify_window[i] = NULL; 884 } 885 } 886 #endif 887 888 #ifdef ASSERT 889 Node* prev = NULL; 890 uint rep_cnt = 0; 891 #endif 892 uint loop_count = 0; 893 894 // Pull from worklist; transform node; 895 // If node has changed: update edge info and put uses on worklist. 896 while( _worklist.size() ) { 897 if (C->check_node_count(NodeLimitFudgeFactor * 2, 898 "out of nodes optimizing method")) { 899 return; 900 } 901 Node *n = _worklist.pop(); 902 if (++loop_count >= K * C->live_nodes()) { 903 debug_only(n->dump(4);) 904 assert(false, "infinite loop in PhaseIterGVN::optimize"); 905 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize"); 906 return; 907 } 908 #ifdef ASSERT 909 if (n == prev) { 910 if (++rep_cnt > 3) { 911 n->dump(4); 912 assert(false, "loop in Ideal transformation"); 913 } 914 } else { 915 rep_cnt = 0; 916 } 917 prev = n; 918 #endif 919 if (TraceIterativeGVN && Verbose) { 920 tty->print(" Pop "); 921 NOT_PRODUCT( n->dump(); ) 922 debug_only(if( (num_processed++ % 100) == 0 ) _worklist.print_set();) 923 } 924 925 if (n->outcnt() != 0) { 926 927 #ifndef PRODUCT 928 uint wlsize = _worklist.size(); 929 const Type* oldtype = type_or_null(n); 930 #endif //PRODUCT 931 932 Node *nn = transform_old(n); 933 934 #ifndef PRODUCT 935 if (TraceIterativeGVN) { 936 const Type* newtype = type_or_null(n); 937 if (nn != n) { 938 // print old node 939 tty->print("< "); 940 if (oldtype != newtype && oldtype != NULL) { 941 oldtype->dump(); 942 } 943 do { tty->print("\t"); } while (tty->position() < 16); 944 tty->print("<"); 945 n->dump(); 946 } 947 if (oldtype != newtype || nn != n) { 948 // print new node and/or new type 949 if (oldtype == NULL) { 950 tty->print("* "); 951 } else if (nn != n) { 952 tty->print("> "); 953 } else { 954 tty->print("= "); 955 } 956 if (newtype == NULL) { 957 tty->print("null"); 958 } else { 959 newtype->dump(); 960 } 961 do { tty->print("\t"); } while (tty->position() < 16); 962 nn->dump(); 963 } 964 if (Verbose && wlsize < _worklist.size()) { 965 tty->print(" Push {"); 966 while (wlsize != _worklist.size()) { 967 Node* pushed = _worklist.at(wlsize++); 968 tty->print(" %d", pushed->_idx); 969 } 970 tty->print_cr(" }"); 971 } 972 } 973 if( VerifyIterativeGVN && nn != n ) { 974 verify_step((Node*) NULL); // ignore n, it might be subsumed 975 } 976 #endif 977 } else if (!n->is_top()) { 978 remove_dead_node(n); 979 } 980 } 981 982 #ifndef PRODUCT 983 C->verify_graph_edges(); 984 if( VerifyOpto && allow_progress() ) { 985 // Must turn off allow_progress to enable assert and break recursion 986 C->root()->verify(); 987 { // Check if any progress was missed using IterGVN 988 // Def-Use info enables transformations not attempted in wash-pass 989 // e.g. Region/Phi cleanup, ... 990 // Null-check elision -- may not have reached fixpoint 991 // do not propagate to dominated nodes 992 ResourceMark rm; 993 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean! 994 // Fill worklist completely 995 igvn2.init_worklist(C->root()); 996 997 igvn2.set_allow_progress(false); 998 igvn2.optimize(); 999 igvn2.set_allow_progress(true); 1000 } 1001 } 1002 if ( VerifyIterativeGVN && PrintOpto ) { 1003 if ( _verify_counter == _verify_full_passes ) 1004 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes", 1005 _verify_full_passes); 1006 else 1007 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes", 1008 _verify_counter, _verify_full_passes); 1009 } 1010 #endif 1011 } 1012 1013 1014 //------------------register_new_node_with_optimizer--------------------------- 1015 // Register a new node with the optimizer. Update the types array, the def-use 1016 // info. Put on worklist. 1017 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) { 1018 set_type_bottom(n); 1019 _worklist.push(n); 1020 if (orig != NULL) C->copy_node_notes_to(n, orig); 1021 return n; 1022 } 1023 1024 //------------------------------transform-------------------------------------- 1025 // Non-recursive: idealize Node 'n' with respect to its inputs and its value 1026 Node *PhaseIterGVN::transform( Node *n ) { 1027 if (_delay_transform) { 1028 // Register the node but don't optimize for now 1029 register_new_node_with_optimizer(n); 1030 return n; 1031 } 1032 1033 // If brand new node, make space in type array, and give it a type. 1034 ensure_type_or_null(n); 1035 if (type_or_null(n) == NULL) { 1036 set_type_bottom(n); 1037 } 1038 1039 return transform_old(n); 1040 } 1041 1042 //------------------------------transform_old---------------------------------- 1043 Node *PhaseIterGVN::transform_old( Node *n ) { 1044 #ifndef PRODUCT 1045 debug_only(uint loop_count = 0;); 1046 set_transforms(); 1047 #endif 1048 // Remove 'n' from hash table in case it gets modified 1049 _table.hash_delete(n); 1050 if( VerifyIterativeGVN ) { 1051 assert( !_table.find_index(n->_idx), "found duplicate entry in table"); 1052 } 1053 1054 // Apply the Ideal call in a loop until it no longer applies 1055 Node *k = n; 1056 DEBUG_ONLY(dead_loop_check(k);) 1057 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);) 1058 Node *i = k->Ideal(this, /*can_reshape=*/true); 1059 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes"); 1060 #ifndef PRODUCT 1061 if( VerifyIterativeGVN ) 1062 verify_step(k); 1063 if( i && VerifyOpto ) { 1064 if( !allow_progress() ) { 1065 if (i->is_Add() && i->outcnt() == 1) { 1066 // Switched input to left side because this is the only use 1067 } else if( i->is_If() && (i->in(0) == NULL) ) { 1068 // This IF is dead because it is dominated by an equivalent IF When 1069 // dominating if changed, info is not propagated sparsely to 'this' 1070 // Propagating this info further will spuriously identify other 1071 // progress. 1072 return i; 1073 } else 1074 set_progress(); 1075 } else 1076 set_progress(); 1077 } 1078 #endif 1079 1080 while( i ) { 1081 #ifndef PRODUCT 1082 debug_only( if( loop_count >= K ) i->dump(4); ) 1083 assert(loop_count < K, "infinite loop in PhaseIterGVN::transform"); 1084 debug_only( loop_count++; ) 1085 #endif 1086 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes"); 1087 // Made a change; put users of original Node on worklist 1088 add_users_to_worklist( k ); 1089 // Replacing root of transform tree? 1090 if( k != i ) { 1091 // Make users of old Node now use new. 1092 subsume_node( k, i ); 1093 k = i; 1094 } 1095 DEBUG_ONLY(dead_loop_check(k);) 1096 // Try idealizing again 1097 DEBUG_ONLY(is_new = (k->outcnt() == 0);) 1098 i = k->Ideal(this, /*can_reshape=*/true); 1099 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes"); 1100 #ifndef PRODUCT 1101 if( VerifyIterativeGVN ) 1102 verify_step(k); 1103 if( i && VerifyOpto ) set_progress(); 1104 #endif 1105 } 1106 1107 // If brand new node, make space in type array. 1108 ensure_type_or_null(k); 1109 1110 // See what kind of values 'k' takes on at runtime 1111 const Type *t = k->Value(this); 1112 assert(t != NULL, "value sanity"); 1113 1114 // Since I just called 'Value' to compute the set of run-time values 1115 // for this Node, and 'Value' is non-local (and therefore expensive) I'll 1116 // cache Value. Later requests for the local phase->type of this Node can 1117 // use the cached Value instead of suffering with 'bottom_type'. 1118 if (t != type_or_null(k)) { 1119 NOT_PRODUCT( set_progress(); ) 1120 NOT_PRODUCT( inc_new_values();) 1121 set_type(k, t); 1122 // If k is a TypeNode, capture any more-precise type permanently into Node 1123 k->raise_bottom_type(t); 1124 // Move users of node to worklist 1125 add_users_to_worklist( k ); 1126 } 1127 1128 // If 'k' computes a constant, replace it with a constant 1129 if( t->singleton() && !k->is_Con() ) { 1130 NOT_PRODUCT( set_progress(); ) 1131 Node *con = makecon(t); // Make a constant 1132 add_users_to_worklist( k ); 1133 subsume_node( k, con ); // Everybody using k now uses con 1134 return con; 1135 } 1136 1137 // Now check for Identities 1138 i = k->Identity(this); // Look for a nearby replacement 1139 if( i != k ) { // Found? Return replacement! 1140 NOT_PRODUCT( set_progress(); ) 1141 add_users_to_worklist( k ); 1142 subsume_node( k, i ); // Everybody using k now uses i 1143 return i; 1144 } 1145 1146 // Global Value Numbering 1147 i = hash_find_insert(k); // Check for pre-existing node 1148 if( i && (i != k) ) { 1149 // Return the pre-existing node if it isn't dead 1150 NOT_PRODUCT( set_progress(); ) 1151 add_users_to_worklist( k ); 1152 subsume_node( k, i ); // Everybody using k now uses i 1153 return i; 1154 } 1155 1156 // Return Idealized original 1157 return k; 1158 } 1159 1160 //---------------------------------saturate------------------------------------ 1161 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type, 1162 const Type* limit_type) const { 1163 return new_type->narrow(old_type); 1164 } 1165 1166 //------------------------------remove_globally_dead_node---------------------- 1167 // Kill a globally dead Node. All uses are also globally dead and are 1168 // aggressively trimmed. 1169 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) { 1170 enum DeleteProgress { 1171 PROCESS_INPUTS, 1172 PROCESS_OUTPUTS 1173 }; 1174 assert(_stack.is_empty(), "not empty"); 1175 _stack.push(dead, PROCESS_INPUTS); 1176 1177 while (_stack.is_nonempty()) { 1178 dead = _stack.node(); 1179 uint progress_state = _stack.index(); 1180 assert(dead != C->root(), "killing root, eh?"); 1181 assert(!dead->is_top(), "add check for top when pushing"); 1182 NOT_PRODUCT( set_progress(); ) 1183 if (progress_state == PROCESS_INPUTS) { 1184 // After following inputs, continue to outputs 1185 _stack.set_index(PROCESS_OUTPUTS); 1186 if (!dead->is_Con()) { // Don't kill cons but uses 1187 bool recurse = false; 1188 // Remove from hash table 1189 _table.hash_delete( dead ); 1190 // Smash all inputs to 'dead', isolating him completely 1191 for (uint i = 0; i < dead->req(); i++) { 1192 Node *in = dead->in(i); 1193 if (in != NULL && in != C->top()) { // Points to something? 1194 int nrep = dead->replace_edge(in, NULL); // Kill edges 1195 assert((nrep > 0), "sanity"); 1196 if (in->outcnt() == 0) { // Made input go dead? 1197 _stack.push(in, PROCESS_INPUTS); // Recursively remove 1198 recurse = true; 1199 } else if (in->outcnt() == 1 && 1200 in->has_special_unique_user()) { 1201 _worklist.push(in->unique_out()); 1202 } else if (in->outcnt() <= 2 && dead->is_Phi()) { 1203 if (in->Opcode() == Op_Region) { 1204 _worklist.push(in); 1205 } else if (in->is_Store()) { 1206 DUIterator_Fast imax, i = in->fast_outs(imax); 1207 _worklist.push(in->fast_out(i)); 1208 i++; 1209 if (in->outcnt() == 2) { 1210 _worklist.push(in->fast_out(i)); 1211 i++; 1212 } 1213 assert(!(i < imax), "sanity"); 1214 } 1215 } 1216 if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory && 1217 in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) { 1218 // A Load that directly follows an InitializeNode is 1219 // going away. The Stores that follow are candidates 1220 // again to be captured by the InitializeNode. 1221 for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) { 1222 Node *n = in->fast_out(j); 1223 if (n->is_Store()) { 1224 _worklist.push(n); 1225 } 1226 } 1227 } 1228 } // if (in != NULL && in != C->top()) 1229 } // for (uint i = 0; i < dead->req(); i++) 1230 if (recurse) { 1231 continue; 1232 } 1233 } // if (!dead->is_Con()) 1234 } // if (progress_state == PROCESS_INPUTS) 1235 1236 // Aggressively kill globally dead uses 1237 // (Rather than pushing all the outs at once, we push one at a time, 1238 // plus the parent to resume later, because of the indefinite number 1239 // of edge deletions per loop trip.) 1240 if (dead->outcnt() > 0) { 1241 // Recursively remove output edges 1242 _stack.push(dead->raw_out(0), PROCESS_INPUTS); 1243 } else { 1244 // Finished disconnecting all input and output edges. 1245 _stack.pop(); 1246 // Remove dead node from iterative worklist 1247 _worklist.remove(dead); 1248 // Constant node that has no out-edges and has only one in-edge from 1249 // root is usually dead. However, sometimes reshaping walk makes 1250 // it reachable by adding use edges. So, we will NOT count Con nodes 1251 // as dead to be conservative about the dead node count at any 1252 // given time. 1253 if (!dead->is_Con()) { 1254 C->record_dead_node(dead->_idx); 1255 } 1256 if (dead->is_macro()) { 1257 C->remove_macro_node(dead); 1258 } 1259 if (dead->is_expensive()) { 1260 C->remove_expensive_node(dead); 1261 } 1262 } 1263 } // while (_stack.is_nonempty()) 1264 } 1265 1266 //------------------------------subsume_node----------------------------------- 1267 // Remove users from node 'old' and add them to node 'nn'. 1268 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) { 1269 assert( old != hash_find(old), "should already been removed" ); 1270 assert( old != C->top(), "cannot subsume top node"); 1271 // Copy debug or profile information to the new version: 1272 C->copy_node_notes_to(nn, old); 1273 // Move users of node 'old' to node 'nn' 1274 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) { 1275 Node* use = old->last_out(i); // for each use... 1276 // use might need re-hashing (but it won't if it's a new node) 1277 bool is_in_table = _table.hash_delete( use ); 1278 // Update use-def info as well 1279 // We remove all occurrences of old within use->in, 1280 // so as to avoid rehashing any node more than once. 1281 // The hash table probe swamps any outer loop overhead. 1282 uint num_edges = 0; 1283 for (uint jmax = use->len(), j = 0; j < jmax; j++) { 1284 if (use->in(j) == old) { 1285 use->set_req(j, nn); 1286 ++num_edges; 1287 } 1288 } 1289 // Insert into GVN hash table if unique 1290 // If a duplicate, 'use' will be cleaned up when pulled off worklist 1291 if( is_in_table ) { 1292 hash_find_insert(use); 1293 } 1294 i -= num_edges; // we deleted 1 or more copies of this edge 1295 } 1296 1297 // Smash all inputs to 'old', isolating him completely 1298 Node *temp = new (C) Node(1); 1299 temp->init_req(0,nn); // Add a use to nn to prevent him from dying 1300 remove_dead_node( old ); 1301 temp->del_req(0); // Yank bogus edge 1302 #ifndef PRODUCT 1303 if( VerifyIterativeGVN ) { 1304 for ( int i = 0; i < _verify_window_size; i++ ) { 1305 if ( _verify_window[i] == old ) 1306 _verify_window[i] = nn; 1307 } 1308 } 1309 #endif 1310 _worklist.remove(temp); // this can be necessary 1311 temp->destruct(); // reuse the _idx of this little guy 1312 } 1313 1314 //------------------------------add_users_to_worklist-------------------------- 1315 void PhaseIterGVN::add_users_to_worklist0( Node *n ) { 1316 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 1317 _worklist.push(n->fast_out(i)); // Push on worklist 1318 } 1319 } 1320 1321 void PhaseIterGVN::add_users_to_worklist( Node *n ) { 1322 add_users_to_worklist0(n); 1323 1324 // Move users of node to worklist 1325 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 1326 Node* use = n->fast_out(i); // Get use 1327 1328 if( use->is_Multi() || // Multi-definer? Push projs on worklist 1329 use->is_Store() ) // Enable store/load same address 1330 add_users_to_worklist0(use); 1331 1332 // If we changed the receiver type to a call, we need to revisit 1333 // the Catch following the call. It's looking for a non-NULL 1334 // receiver to know when to enable the regular fall-through path 1335 // in addition to the NullPtrException path. 1336 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) { 1337 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control); 1338 if (p != NULL) { 1339 add_users_to_worklist0(p); 1340 } 1341 } 1342 1343 if( use->is_Cmp() ) { // Enable CMP/BOOL optimization 1344 add_users_to_worklist(use); // Put Bool on worklist 1345 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the 1346 // phi merging either 0 or 1 onto the worklist 1347 if (use->outcnt() > 0) { 1348 Node* bol = use->raw_out(0); 1349 if (bol->outcnt() > 0) { 1350 Node* iff = bol->raw_out(0); 1351 if (iff->outcnt() == 2) { 1352 Node* ifproj0 = iff->raw_out(0); 1353 Node* ifproj1 = iff->raw_out(1); 1354 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) { 1355 Node* region0 = ifproj0->raw_out(0); 1356 Node* region1 = ifproj1->raw_out(0); 1357 if( region0 == region1 ) 1358 add_users_to_worklist0(region0); 1359 } 1360 } 1361 } 1362 } 1363 } 1364 1365 uint use_op = use->Opcode(); 1366 // If changed Cast input, check Phi users for simple cycles 1367 if( use->is_ConstraintCast() || use->is_CheckCastPP() ) { 1368 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) { 1369 Node* u = use->fast_out(i2); 1370 if (u->is_Phi()) 1371 _worklist.push(u); 1372 } 1373 } 1374 // If changed LShift inputs, check RShift users for useless sign-ext 1375 if( use_op == Op_LShiftI ) { 1376 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) { 1377 Node* u = use->fast_out(i2); 1378 if (u->Opcode() == Op_RShiftI) 1379 _worklist.push(u); 1380 } 1381 } 1382 // If changed AddP inputs, check Stores for loop invariant 1383 if( use_op == Op_AddP ) { 1384 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) { 1385 Node* u = use->fast_out(i2); 1386 if (u->is_Mem()) 1387 _worklist.push(u); 1388 } 1389 } 1390 // If changed initialization activity, check dependent Stores 1391 if (use_op == Op_Allocate || use_op == Op_AllocateArray) { 1392 InitializeNode* init = use->as_Allocate()->initialization(); 1393 if (init != NULL) { 1394 Node* imem = init->proj_out(TypeFunc::Memory); 1395 if (imem != NULL) add_users_to_worklist0(imem); 1396 } 1397 } 1398 if (use_op == Op_Initialize) { 1399 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory); 1400 if (imem != NULL) add_users_to_worklist0(imem); 1401 } 1402 } 1403 } 1404 1405 /** 1406 * Remove the speculative part of all types that we know of 1407 */ 1408 void PhaseIterGVN::remove_speculative_types() { 1409 assert(UseTypeSpeculation, "speculation is off"); 1410 for (uint i = 0; i < _types.Size(); i++) { 1411 const Type* t = _types.fast_lookup(i); 1412 if (t != NULL) { 1413 _types.map(i, t->remove_speculative()); 1414 } 1415 } 1416 _table.check_no_speculative_types(); 1417 } 1418 1419 //============================================================================= 1420 #ifndef PRODUCT 1421 uint PhaseCCP::_total_invokes = 0; 1422 uint PhaseCCP::_total_constants = 0; 1423 #endif 1424 //------------------------------PhaseCCP--------------------------------------- 1425 // Conditional Constant Propagation, ala Wegman & Zadeck 1426 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) { 1427 NOT_PRODUCT( clear_constants(); ) 1428 assert( _worklist.size() == 0, "" ); 1429 // Clear out _nodes from IterGVN. Must be clear to transform call. 1430 _nodes.clear(); // Clear out from IterGVN 1431 analyze(); 1432 } 1433 1434 #ifndef PRODUCT 1435 //------------------------------~PhaseCCP-------------------------------------- 1436 PhaseCCP::~PhaseCCP() { 1437 inc_invokes(); 1438 _total_constants += count_constants(); 1439 } 1440 #endif 1441 1442 1443 #ifdef ASSERT 1444 static bool ccp_type_widens(const Type* t, const Type* t0) { 1445 assert(t->meet(t0) == t, "Not monotonic"); 1446 switch (t->base() == t0->base() ? t->base() : Type::Top) { 1447 case Type::Int: 1448 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases"); 1449 break; 1450 case Type::Long: 1451 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases"); 1452 break; 1453 } 1454 return true; 1455 } 1456 #endif //ASSERT 1457 1458 //------------------------------analyze---------------------------------------- 1459 void PhaseCCP::analyze() { 1460 // Initialize all types to TOP, optimistic analysis 1461 for (int i = C->unique() - 1; i >= 0; i--) { 1462 _types.map(i,Type::TOP); 1463 } 1464 1465 // Push root onto worklist 1466 Unique_Node_List worklist; 1467 worklist.push(C->root()); 1468 1469 // Pull from worklist; compute new value; push changes out. 1470 // This loop is the meat of CCP. 1471 while( worklist.size() ) { 1472 Node *n = worklist.pop(); 1473 const Type *t = n->Value(this); 1474 if (t != type(n)) { 1475 assert(ccp_type_widens(t, type(n)), "ccp type must widen"); 1476 #ifndef PRODUCT 1477 if( TracePhaseCCP ) { 1478 t->dump(); 1479 do { tty->print("\t"); } while (tty->position() < 16); 1480 n->dump(); 1481 } 1482 #endif 1483 set_type(n, t); 1484 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 1485 Node* m = n->fast_out(i); // Get user 1486 if( m->is_Region() ) { // New path to Region? Must recheck Phis too 1487 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) { 1488 Node* p = m->fast_out(i2); // Propagate changes to uses 1489 if( p->bottom_type() != type(p) ) // If not already bottomed out 1490 worklist.push(p); // Propagate change to user 1491 } 1492 } 1493 // If we changed the receiver type to a call, we need to revisit 1494 // the Catch following the call. It's looking for a non-NULL 1495 // receiver to know when to enable the regular fall-through path 1496 // in addition to the NullPtrException path 1497 if (m->is_Call()) { 1498 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) { 1499 Node* p = m->fast_out(i2); // Propagate changes to uses 1500 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1) 1501 worklist.push(p->unique_out()); 1502 } 1503 } 1504 if( m->bottom_type() != type(m) ) // If not already bottomed out 1505 worklist.push(m); // Propagate change to user 1506 } 1507 } 1508 } 1509 } 1510 1511 //------------------------------do_transform----------------------------------- 1512 // Top level driver for the recursive transformer 1513 void PhaseCCP::do_transform() { 1514 // Correct leaves of new-space Nodes; they point to old-space. 1515 C->set_root( transform(C->root())->as_Root() ); 1516 assert( C->top(), "missing TOP node" ); 1517 assert( C->root(), "missing root" ); 1518 } 1519 1520 //------------------------------transform-------------------------------------- 1521 // Given a Node in old-space, clone him into new-space. 1522 // Convert any of his old-space children into new-space children. 1523 Node *PhaseCCP::transform( Node *n ) { 1524 Node *new_node = _nodes[n->_idx]; // Check for transformed node 1525 if( new_node != NULL ) 1526 return new_node; // Been there, done that, return old answer 1527 new_node = transform_once(n); // Check for constant 1528 _nodes.map( n->_idx, new_node ); // Flag as having been cloned 1529 1530 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc 1531 GrowableArray <Node *> trstack(C->unique() >> 1); 1532 1533 trstack.push(new_node); // Process children of cloned node 1534 while ( trstack.is_nonempty() ) { 1535 Node *clone = trstack.pop(); 1536 uint cnt = clone->req(); 1537 for( uint i = 0; i < cnt; i++ ) { // For all inputs do 1538 Node *input = clone->in(i); 1539 if( input != NULL ) { // Ignore NULLs 1540 Node *new_input = _nodes[input->_idx]; // Check for cloned input node 1541 if( new_input == NULL ) { 1542 new_input = transform_once(input); // Check for constant 1543 _nodes.map( input->_idx, new_input );// Flag as having been cloned 1544 trstack.push(new_input); 1545 } 1546 assert( new_input == clone->in(i), "insanity check"); 1547 } 1548 } 1549 } 1550 return new_node; 1551 } 1552 1553 1554 //------------------------------transform_once--------------------------------- 1555 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant. 1556 Node *PhaseCCP::transform_once( Node *n ) { 1557 const Type *t = type(n); 1558 // Constant? Use constant Node instead 1559 if( t->singleton() ) { 1560 Node *nn = n; // Default is to return the original constant 1561 if( t == Type::TOP ) { 1562 // cache my top node on the Compile instance 1563 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) { 1564 C->set_cached_top_node( ConNode::make(C, Type::TOP) ); 1565 set_type(C->top(), Type::TOP); 1566 } 1567 nn = C->top(); 1568 } 1569 if( !n->is_Con() ) { 1570 if( t != Type::TOP ) { 1571 nn = makecon(t); // ConNode::make(t); 1572 NOT_PRODUCT( inc_constants(); ) 1573 } else if( n->is_Region() ) { // Unreachable region 1574 // Note: nn == C->top() 1575 n->set_req(0, NULL); // Cut selfreference 1576 // Eagerly remove dead phis to avoid phis copies creation. 1577 for (DUIterator i = n->outs(); n->has_out(i); i++) { 1578 Node* m = n->out(i); 1579 if( m->is_Phi() ) { 1580 assert(type(m) == Type::TOP, "Unreachable region should not have live phis."); 1581 replace_node(m, nn); 1582 --i; // deleted this phi; rescan starting with next position 1583 } 1584 } 1585 } 1586 replace_node(n,nn); // Update DefUse edges for new constant 1587 } 1588 return nn; 1589 } 1590 1591 // If x is a TypeNode, capture any more-precise type permanently into Node 1592 if (t != n->bottom_type()) { 1593 hash_delete(n); // changing bottom type may force a rehash 1594 n->raise_bottom_type(t); 1595 _worklist.push(n); // n re-enters the hash table via the worklist 1596 } 1597 1598 // Idealize graph using DU info. Must clone() into new-space. 1599 // DU info is generally used to show profitability, progress or safety 1600 // (but generally not needed for correctness). 1601 Node *nn = n->Ideal_DU_postCCP(this); 1602 1603 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks 1604 switch( n->Opcode() ) { 1605 case Op_FastLock: // Revisit FastLocks for lock coarsening 1606 case Op_If: 1607 case Op_CountedLoopEnd: 1608 case Op_Region: 1609 case Op_Loop: 1610 case Op_CountedLoop: 1611 case Op_Conv2B: 1612 case Op_Opaque1: 1613 case Op_Opaque2: 1614 _worklist.push(n); 1615 break; 1616 default: 1617 break; 1618 } 1619 if( nn ) { 1620 _worklist.push(n); 1621 // Put users of 'n' onto worklist for second igvn transform 1622 add_users_to_worklist(n); 1623 return nn; 1624 } 1625 1626 return n; 1627 } 1628 1629 //---------------------------------saturate------------------------------------ 1630 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type, 1631 const Type* limit_type) const { 1632 const Type* wide_type = new_type->widen(old_type, limit_type); 1633 if (wide_type != new_type) { // did we widen? 1634 // If so, we may have widened beyond the limit type. Clip it back down. 1635 new_type = wide_type->filter(limit_type); 1636 } 1637 return new_type; 1638 } 1639 1640 //------------------------------print_statistics------------------------------- 1641 #ifndef PRODUCT 1642 void PhaseCCP::print_statistics() { 1643 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants); 1644 } 1645 #endif 1646 1647 1648 //============================================================================= 1649 #ifndef PRODUCT 1650 uint PhasePeephole::_total_peepholes = 0; 1651 #endif 1652 //------------------------------PhasePeephole---------------------------------- 1653 // Conditional Constant Propagation, ala Wegman & Zadeck 1654 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg ) 1655 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) { 1656 NOT_PRODUCT( clear_peepholes(); ) 1657 } 1658 1659 #ifndef PRODUCT 1660 //------------------------------~PhasePeephole--------------------------------- 1661 PhasePeephole::~PhasePeephole() { 1662 _total_peepholes += count_peepholes(); 1663 } 1664 #endif 1665 1666 //------------------------------transform-------------------------------------- 1667 Node *PhasePeephole::transform( Node *n ) { 1668 ShouldNotCallThis(); 1669 return NULL; 1670 } 1671 1672 //------------------------------do_transform----------------------------------- 1673 void PhasePeephole::do_transform() { 1674 bool method_name_not_printed = true; 1675 1676 // Examine each basic block 1677 for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) { 1678 Block* block = _cfg.get_block(block_number); 1679 bool block_not_printed = true; 1680 1681 // and each instruction within a block 1682 uint end_index = block->number_of_nodes(); 1683 // block->end_idx() not valid after PhaseRegAlloc 1684 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) { 1685 Node *n = block->get_node(instruction_index); 1686 if( n->is_Mach() ) { 1687 MachNode *m = n->as_Mach(); 1688 int deleted_count = 0; 1689 // check for peephole opportunities 1690 MachNode *m2 = m->peephole( block, instruction_index, _regalloc, deleted_count, C ); 1691 if( m2 != NULL ) { 1692 #ifndef PRODUCT 1693 if( PrintOptoPeephole ) { 1694 // Print method, first time only 1695 if( C->method() && method_name_not_printed ) { 1696 C->method()->print_short_name(); tty->cr(); 1697 method_name_not_printed = false; 1698 } 1699 // Print this block 1700 if( Verbose && block_not_printed) { 1701 tty->print_cr("in block"); 1702 block->dump(); 1703 block_not_printed = false; 1704 } 1705 // Print instructions being deleted 1706 for( int i = (deleted_count - 1); i >= 0; --i ) { 1707 block->get_node(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr(); 1708 } 1709 tty->print_cr("replaced with"); 1710 // Print new instruction 1711 m2->format(_regalloc); 1712 tty->print("\n\n"); 1713 } 1714 #endif 1715 // Remove old nodes from basic block and update instruction_index 1716 // (old nodes still exist and may have edges pointing to them 1717 // as register allocation info is stored in the allocator using 1718 // the node index to live range mappings.) 1719 uint safe_instruction_index = (instruction_index - deleted_count); 1720 for( ; (instruction_index > safe_instruction_index); --instruction_index ) { 1721 block->remove_node( instruction_index ); 1722 } 1723 // install new node after safe_instruction_index 1724 block->insert_node(m2, safe_instruction_index + 1); 1725 end_index = block->number_of_nodes() - 1; // Recompute new block size 1726 NOT_PRODUCT( inc_peepholes(); ) 1727 } 1728 } 1729 } 1730 } 1731 } 1732 1733 //------------------------------print_statistics------------------------------- 1734 #ifndef PRODUCT 1735 void PhasePeephole::print_statistics() { 1736 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes); 1737 } 1738 #endif 1739 1740 1741 //============================================================================= 1742 //------------------------------set_req_X-------------------------------------- 1743 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) { 1744 assert( is_not_dead(n), "can not use dead node"); 1745 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" ); 1746 Node *old = in(i); 1747 set_req(i, n); 1748 1749 // old goes dead? 1750 if( old ) { 1751 switch (old->outcnt()) { 1752 case 0: 1753 // Put into the worklist to kill later. We do not kill it now because the 1754 // recursive kill will delete the current node (this) if dead-loop exists 1755 if (!old->is_top()) 1756 igvn->_worklist.push( old ); 1757 break; 1758 case 1: 1759 if( old->is_Store() || old->has_special_unique_user() ) 1760 igvn->add_users_to_worklist( old ); 1761 break; 1762 case 2: 1763 if( old->is_Store() ) 1764 igvn->add_users_to_worklist( old ); 1765 if( old->Opcode() == Op_Region ) 1766 igvn->_worklist.push(old); 1767 break; 1768 case 3: 1769 if( old->Opcode() == Op_Region ) { 1770 igvn->_worklist.push(old); 1771 igvn->add_users_to_worklist( old ); 1772 } 1773 break; 1774 default: 1775 break; 1776 } 1777 } 1778 1779 } 1780 1781 //-------------------------------replace_by----------------------------------- 1782 // Using def-use info, replace one node for another. Follow the def-use info 1783 // to all users of the OLD node. Then make all uses point to the NEW node. 1784 void Node::replace_by(Node *new_node) { 1785 assert(!is_top(), "top node has no DU info"); 1786 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) { 1787 Node* use = last_out(i); 1788 uint uses_found = 0; 1789 for (uint j = 0; j < use->len(); j++) { 1790 if (use->in(j) == this) { 1791 if (j < use->req()) 1792 use->set_req(j, new_node); 1793 else use->set_prec(j, new_node); 1794 uses_found++; 1795 } 1796 } 1797 i -= uses_found; // we deleted 1 or more copies of this edge 1798 } 1799 } 1800 1801 //============================================================================= 1802 //----------------------------------------------------------------------------- 1803 void Type_Array::grow( uint i ) { 1804 if( !_max ) { 1805 _max = 1; 1806 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) ); 1807 _types[0] = NULL; 1808 } 1809 uint old = _max; 1810 while( i >= _max ) _max <<= 1; // Double to fit 1811 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*)); 1812 memset( &_types[old], 0, (_max-old)*sizeof(Type*) ); 1813 } 1814 1815 //------------------------------dump------------------------------------------- 1816 #ifndef PRODUCT 1817 void Type_Array::dump() const { 1818 uint max = Size(); 1819 for( uint i = 0; i < max; i++ ) { 1820 if( _types[i] != NULL ) { 1821 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr(); 1822 } 1823 } 1824 } 1825 #endif