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