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