phaseX.cpp revision 1472:c18cbe5936b8
1/* 2 * Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "incls/_precompiled.incl" 26#include "incls/_phaseX.cpp.incl" 27 28//============================================================================= 29#define NODE_HASH_MINIMUM_SIZE 255 30//------------------------------NodeHash--------------------------------------- 31NodeHash::NodeHash(uint est_max_size) : 32 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ), 33 _a(Thread::current()->resource_area()), 34 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ), 35 _inserts(0), _insert_limit( insert_limit() ), 36 _look_probes(0), _lookup_hits(0), _lookup_misses(0), 37 _total_insert_probes(0), _total_inserts(0), 38 _insert_probes(0), _grows(0) { 39 // _sentinel must be in the current node space 40 _sentinel = new (Compile::current(), 1) ProjNode(NULL, TypeFunc::Control); 41 memset(_table,0,sizeof(Node*)*_max); 42} 43 44//------------------------------NodeHash--------------------------------------- 45NodeHash::NodeHash(Arena *arena, uint est_max_size) : 46 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ), 47 _a(arena), 48 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), 49 _inserts(0), _insert_limit( insert_limit() ), 50 _look_probes(0), _lookup_hits(0), _lookup_misses(0), 51 _delete_probes(0), _delete_hits(0), _delete_misses(0), 52 _total_insert_probes(0), _total_inserts(0), 53 _insert_probes(0), _grows(0) { 54 // _sentinel must be in the current node space 55 _sentinel = new (Compile::current(), 1) ProjNode(NULL, TypeFunc::Control); 56 memset(_table,0,sizeof(Node*)*_max); 57} 58 59//------------------------------NodeHash--------------------------------------- 60NodeHash::NodeHash(NodeHash *nh) { 61 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator= 62 // just copy in all the fields 63 *this = *nh; 64 // nh->_sentinel must be in the current node space 65} 66 67//------------------------------hash_find-------------------------------------- 68// Find in hash table 69Node *NodeHash::hash_find( const Node *n ) { 70 // ((Node*)n)->set_hash( n->hash() ); 71 uint hash = n->hash(); 72 if (hash == Node::NO_HASH) { 73 debug_only( _lookup_misses++ ); 74 return NULL; 75 } 76 uint key = hash & (_max-1); 77 uint stride = key | 0x01; 78 debug_only( _look_probes++ ); 79 Node *k = _table[key]; // Get hashed value 80 if( !k ) { // ?Miss? 81 debug_only( _lookup_misses++ ); 82 return NULL; // Miss! 83 } 84 85 int op = n->Opcode(); 86 uint req = n->req(); 87 while( 1 ) { // While probing hash table 88 if( k->req() == req && // Same count of inputs 89 k->Opcode() == op ) { // Same Opcode 90 for( uint i=0; i<req; i++ ) 91 if( n->in(i)!=k->in(i)) // Different inputs? 92 goto collision; // "goto" is a speed hack... 93 if( n->cmp(*k) ) { // Check for any special bits 94 debug_only( _lookup_hits++ ); 95 return k; // Hit! 96 } 97 } 98 collision: 99 debug_only( _look_probes++ ); 100 key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime 101 k = _table[key]; // Get hashed value 102 if( !k ) { // ?Miss? 103 debug_only( _lookup_misses++ ); 104 return NULL; // Miss! 105 } 106 } 107 ShouldNotReachHere(); 108 return NULL; 109} 110 111//------------------------------hash_find_insert------------------------------- 112// Find in hash table, insert if not already present 113// Used to preserve unique entries in hash table 114Node *NodeHash::hash_find_insert( Node *n ) { 115 // n->set_hash( ); 116 uint hash = n->hash(); 117 if (hash == Node::NO_HASH) { 118 debug_only( _lookup_misses++ ); 119 return NULL; 120 } 121 uint key = hash & (_max-1); 122 uint stride = key | 0x01; // stride must be relatively prime to table siz 123 uint first_sentinel = 0; // replace a sentinel if seen. 124 debug_only( _look_probes++ ); 125 Node *k = _table[key]; // Get hashed value 126 if( !k ) { // ?Miss? 127 debug_only( _lookup_misses++ ); 128 _table[key] = n; // Insert into table! 129 debug_only(n->enter_hash_lock()); // Lock down the node while in the table. 130 check_grow(); // Grow table if insert hit limit 131 return NULL; // Miss! 132 } 133 else if( k == _sentinel ) { 134 first_sentinel = key; // Can insert here 135 } 136 137 int op = n->Opcode(); 138 uint req = n->req(); 139 while( 1 ) { // While probing hash table 140 if( k->req() == req && // Same count of inputs 141 k->Opcode() == op ) { // Same Opcode 142 for( uint i=0; i<req; i++ ) 143 if( n->in(i)!=k->in(i)) // Different inputs? 144 goto collision; // "goto" is a speed hack... 145 if( n->cmp(*k) ) { // Check for any special bits 146 debug_only( _lookup_hits++ ); 147 return k; // Hit! 148 } 149 } 150 collision: 151 debug_only( _look_probes++ ); 152 key = (key + stride) & (_max-1); // Stride through table w/ relative prime 153 k = _table[key]; // Get hashed value 154 if( !k ) { // ?Miss? 155 debug_only( _lookup_misses++ ); 156 key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel? 157 _table[key] = n; // Insert into table! 158 debug_only(n->enter_hash_lock()); // Lock down the node while in the table. 159 check_grow(); // Grow table if insert hit limit 160 return NULL; // Miss! 161 } 162 else if( first_sentinel == 0 && k == _sentinel ) { 163 first_sentinel = key; // Can insert here 164 } 165 166 } 167 ShouldNotReachHere(); 168 return NULL; 169} 170 171//------------------------------hash_insert------------------------------------ 172// Insert into hash table 173void NodeHash::hash_insert( Node *n ) { 174 // // "conflict" comments -- print nodes that conflict 175 // bool conflict = false; 176 // n->set_hash(); 177 uint hash = n->hash(); 178 if (hash == Node::NO_HASH) { 179 return; 180 } 181 check_grow(); 182 uint key = hash & (_max-1); 183 uint stride = key | 0x01; 184 185 while( 1 ) { // While probing hash table 186 debug_only( _insert_probes++ ); 187 Node *k = _table[key]; // Get hashed value 188 if( !k || (k == _sentinel) ) break; // Found a slot 189 assert( k != n, "already inserted" ); 190 // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; } 191 key = (key + stride) & (_max-1); // Stride through table w/ relative prime 192 } 193 _table[key] = n; // Insert into table! 194 debug_only(n->enter_hash_lock()); // Lock down the node while in the table. 195 // if( conflict ) { n->dump(); } 196} 197 198//------------------------------hash_delete------------------------------------ 199// Replace in hash table with sentinel 200bool NodeHash::hash_delete( const Node *n ) { 201 Node *k; 202 uint hash = n->hash(); 203 if (hash == Node::NO_HASH) { 204 debug_only( _delete_misses++ ); 205 return false; 206 } 207 uint key = hash & (_max-1); 208 uint stride = key | 0x01; 209 debug_only( uint counter = 0; ); 210 for( ; /* (k != NULL) && (k != _sentinel) */; ) { 211 debug_only( counter++ ); 212 debug_only( _delete_probes++ ); 213 k = _table[key]; // Get hashed value 214 if( !k ) { // Miss? 215 debug_only( _delete_misses++ ); 216#ifdef ASSERT 217 if( VerifyOpto ) { 218 for( uint i=0; i < _max; i++ ) 219 assert( _table[i] != n, "changed edges with rehashing" ); 220 } 221#endif 222 return false; // Miss! Not in chain 223 } 224 else if( n == k ) { 225 debug_only( _delete_hits++ ); 226 _table[key] = _sentinel; // Hit! Label as deleted entry 227 debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table. 228 return true; 229 } 230 else { 231 // collision: move through table with prime offset 232 key = (key + stride/*7*/) & (_max-1); 233 assert( counter <= _insert_limit, "Cycle in hash-table"); 234 } 235 } 236 ShouldNotReachHere(); 237 return false; 238} 239 240//------------------------------round_up--------------------------------------- 241// Round up to nearest power of 2 242uint NodeHash::round_up( uint x ) { 243 x += (x>>2); // Add 25% slop 244 if( x <16 ) return 16; // Small stuff 245 uint i=16; 246 while( i < x ) i <<= 1; // Double to fit 247 return i; // Return hash table size 248} 249 250//------------------------------grow------------------------------------------- 251// Grow _table to next power of 2 and insert old entries 252void NodeHash::grow() { 253 // Record old state 254 uint old_max = _max; 255 Node **old_table = _table; 256 // Construct new table with twice the space 257 _grows++; 258 _total_inserts += _inserts; 259 _total_insert_probes += _insert_probes; 260 _inserts = 0; 261 _insert_probes = 0; 262 _max = _max << 1; 263 _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) ); 264 memset(_table,0,sizeof(Node*)*_max); 265 _insert_limit = insert_limit(); 266 // Insert old entries into the new table 267 for( uint i = 0; i < old_max; i++ ) { 268 Node *m = *old_table++; 269 if( !m || m == _sentinel ) continue; 270 debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table. 271 hash_insert(m); 272 } 273} 274 275//------------------------------clear------------------------------------------ 276// Clear all entries in _table to NULL but keep storage 277void NodeHash::clear() { 278#ifdef ASSERT 279 // Unlock all nodes upon removal from table. 280 for (uint i = 0; i < _max; i++) { 281 Node* n = _table[i]; 282 if (!n || n == _sentinel) continue; 283 n->exit_hash_lock(); 284 } 285#endif 286 287 memset( _table, 0, _max * sizeof(Node*) ); 288} 289 290//-----------------------remove_useless_nodes---------------------------------- 291// Remove useless nodes from value table, 292// implementation does not depend on hash function 293void NodeHash::remove_useless_nodes(VectorSet &useful) { 294 295 // Dead nodes in the hash table inherited from GVN should not replace 296 // existing nodes, remove dead nodes. 297 uint max = size(); 298 Node *sentinel_node = sentinel(); 299 for( uint i = 0; i < max; ++i ) { 300 Node *n = at(i); 301 if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) { 302 debug_only(n->exit_hash_lock()); // Unlock the node when removed 303 _table[i] = sentinel_node; // Replace with placeholder 304 } 305 } 306} 307 308#ifndef PRODUCT 309//------------------------------dump------------------------------------------- 310// Dump statistics for the hash table 311void NodeHash::dump() { 312 _total_inserts += _inserts; 313 _total_insert_probes += _insert_probes; 314 if( PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0) ) { // PrintOptoGVN 315 if( PrintCompilation2 ) { 316 for( uint i=0; i<_max; i++ ) 317 if( _table[i] ) 318 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx); 319 } 320 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max); 321 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0); 322 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses)); 323 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts); 324 // sentinels increase lookup cost, but not insert cost 325 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function"); 326 assert( _inserts+(_inserts>>3) < _max, "table too full" ); 327 assert( _inserts*3+100 >= _insert_probes, "bad hash function" ); 328 } 329} 330 331Node *NodeHash::find_index(uint idx) { // For debugging 332 // Find an entry by its index value 333 for( uint i = 0; i < _max; i++ ) { 334 Node *m = _table[i]; 335 if( !m || m == _sentinel ) continue; 336 if( m->_idx == (uint)idx ) return m; 337 } 338 return NULL; 339} 340#endif 341 342#ifdef ASSERT 343NodeHash::~NodeHash() { 344 // Unlock all nodes upon destruction of table. 345 if (_table != (Node**)badAddress) clear(); 346} 347 348void NodeHash::operator=(const NodeHash& nh) { 349 // Unlock all nodes upon replacement of table. 350 if (&nh == this) return; 351 if (_table != (Node**)badAddress) clear(); 352 memcpy(this, &nh, sizeof(*this)); 353 // Do not increment hash_lock counts again. 354 // Instead, be sure we never again use the source table. 355 ((NodeHash*)&nh)->_table = (Node**)badAddress; 356} 357 358 359#endif 360 361 362//============================================================================= 363//------------------------------PhaseRemoveUseless----------------------------- 364// 1) Use a breadthfirst walk to collect useful nodes reachable from root. 365PhaseRemoveUseless::PhaseRemoveUseless( PhaseGVN *gvn, Unique_Node_List *worklist ) : Phase(Remove_Useless), 366 _useful(Thread::current()->resource_area()) { 367 368 // Implementation requires 'UseLoopSafepoints == true' and an edge from root 369 // to each SafePointNode at a backward branch. Inserted in add_safepoint(). 370 if( !UseLoopSafepoints || !OptoRemoveUseless ) return; 371 372 // Identify nodes that are reachable from below, useful. 373 C->identify_useful_nodes(_useful); 374 375 // Remove all useless nodes from PhaseValues' recorded types 376 // Must be done before disconnecting nodes to preserve hash-table-invariant 377 gvn->remove_useless_nodes(_useful.member_set()); 378 379 // Remove all useless nodes from future worklist 380 worklist->remove_useless_nodes(_useful.member_set()); 381 382 // Disconnect 'useless' nodes that are adjacent to useful nodes 383 C->remove_useless_nodes(_useful); 384 385 // Remove edges from "root" to each SafePoint at a backward branch. 386 // They were inserted during parsing (see add_safepoint()) to make infinite 387 // loops without calls or exceptions visible to root, i.e., useful. 388 Node *root = C->root(); 389 if( root != NULL ) { 390 for( uint i = root->req(); i < root->len(); ++i ) { 391 Node *n = root->in(i); 392 if( n != NULL && n->is_SafePoint() ) { 393 root->rm_prec(i); 394 --i; 395 } 396 } 397 } 398} 399 400 401//============================================================================= 402//------------------------------PhaseTransform--------------------------------- 403PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum), 404 _arena(Thread::current()->resource_area()), 405 _nodes(_arena), 406 _types(_arena) 407{ 408 init_con_caches(); 409#ifndef PRODUCT 410 clear_progress(); 411 clear_transforms(); 412 set_allow_progress(true); 413#endif 414 // Force allocation for currently existing nodes 415 _types.map(C->unique(), NULL); 416} 417 418//------------------------------PhaseTransform--------------------------------- 419PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum), 420 _arena(arena), 421 _nodes(arena), 422 _types(arena) 423{ 424 init_con_caches(); 425#ifndef PRODUCT 426 clear_progress(); 427 clear_transforms(); 428 set_allow_progress(true); 429#endif 430 // Force allocation for currently existing nodes 431 _types.map(C->unique(), NULL); 432} 433 434//------------------------------PhaseTransform--------------------------------- 435// Initialize with previously generated type information 436PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum), 437 _arena(pt->_arena), 438 _nodes(pt->_nodes), 439 _types(pt->_types) 440{ 441 init_con_caches(); 442#ifndef PRODUCT 443 clear_progress(); 444 clear_transforms(); 445 set_allow_progress(true); 446#endif 447} 448 449void PhaseTransform::init_con_caches() { 450 memset(_icons,0,sizeof(_icons)); 451 memset(_lcons,0,sizeof(_lcons)); 452 memset(_zcons,0,sizeof(_zcons)); 453} 454 455 456//--------------------------------find_int_type-------------------------------- 457const TypeInt* PhaseTransform::find_int_type(Node* n) { 458 if (n == NULL) return NULL; 459 // Call type_or_null(n) to determine node's type since we might be in 460 // parse phase and call n->Value() may return wrong type. 461 // (For example, a phi node at the beginning of loop parsing is not ready.) 462 const Type* t = type_or_null(n); 463 if (t == NULL) return NULL; 464 return t->isa_int(); 465} 466 467 468//-------------------------------find_long_type-------------------------------- 469const TypeLong* PhaseTransform::find_long_type(Node* n) { 470 if (n == NULL) return NULL; 471 // (See comment above on type_or_null.) 472 const Type* t = type_or_null(n); 473 if (t == NULL) return NULL; 474 return t->isa_long(); 475} 476 477 478#ifndef PRODUCT 479void PhaseTransform::dump_old2new_map() const { 480 _nodes.dump(); 481} 482 483void PhaseTransform::dump_new( uint nidx ) const { 484 for( uint i=0; i<_nodes.Size(); i++ ) 485 if( _nodes[i] && _nodes[i]->_idx == nidx ) { 486 _nodes[i]->dump(); 487 tty->cr(); 488 tty->print_cr("Old index= %d",i); 489 return; 490 } 491 tty->print_cr("Node %d not found in the new indices", nidx); 492} 493 494//------------------------------dump_types------------------------------------- 495void PhaseTransform::dump_types( ) const { 496 _types.dump(); 497} 498 499//------------------------------dump_nodes_and_types--------------------------- 500void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) { 501 VectorSet visited(Thread::current()->resource_area()); 502 dump_nodes_and_types_recur( root, depth, only_ctrl, visited ); 503} 504 505//------------------------------dump_nodes_and_types_recur--------------------- 506void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) { 507 if( !n ) return; 508 if( depth == 0 ) return; 509 if( visited.test_set(n->_idx) ) return; 510 for( uint i=0; i<n->len(); i++ ) { 511 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue; 512 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited ); 513 } 514 n->dump(); 515 if (type_or_null(n) != NULL) { 516 tty->print(" "); type(n)->dump(); tty->cr(); 517 } 518} 519 520#endif 521 522 523//============================================================================= 524//------------------------------PhaseValues------------------------------------ 525// Set minimum table size to "255" 526PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) { 527 NOT_PRODUCT( clear_new_values(); ) 528} 529 530//------------------------------PhaseValues------------------------------------ 531// Set minimum table size to "255" 532PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ), 533 _table(&ptv->_table) { 534 NOT_PRODUCT( clear_new_values(); ) 535} 536 537//------------------------------PhaseValues------------------------------------ 538// Used by +VerifyOpto. Clear out hash table but copy _types array. 539PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ), 540 _table(ptv->arena(),ptv->_table.size()) { 541 NOT_PRODUCT( clear_new_values(); ) 542} 543 544//------------------------------~PhaseValues----------------------------------- 545#ifndef PRODUCT 546PhaseValues::~PhaseValues() { 547 _table.dump(); 548 549 // Statistics for value progress and efficiency 550 if( PrintCompilation && Verbose && WizardMode ) { 551 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)", 552 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values()); 553 if( made_transforms() != 0 ) { 554 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() ); 555 } else { 556 tty->cr(); 557 } 558 } 559} 560#endif 561 562//------------------------------makecon---------------------------------------- 563ConNode* PhaseTransform::makecon(const Type *t) { 564 assert(t->singleton(), "must be a constant"); 565 assert(!t->empty() || t == Type::TOP, "must not be vacuous range"); 566 switch (t->base()) { // fast paths 567 case Type::Half: 568 case Type::Top: return (ConNode*) C->top(); 569 case Type::Int: return intcon( t->is_int()->get_con() ); 570 case Type::Long: return longcon( t->is_long()->get_con() ); 571 } 572 if (t->is_zero_type()) 573 return zerocon(t->basic_type()); 574 return uncached_makecon(t); 575} 576 577//--------------------------uncached_makecon----------------------------------- 578// Make an idealized constant - one of ConINode, ConPNode, etc. 579ConNode* PhaseValues::uncached_makecon(const Type *t) { 580 assert(t->singleton(), "must be a constant"); 581 ConNode* x = ConNode::make(C, t); 582 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering 583 if (k == NULL) { 584 set_type(x, t); // Missed, provide type mapping 585 GrowableArray<Node_Notes*>* nna = C->node_note_array(); 586 if (nna != NULL) { 587 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true); 588 loc->clear(); // do not put debug info on constants 589 } 590 } else { 591 x->destruct(); // Hit, destroy duplicate constant 592 x = k; // use existing constant 593 } 594 return x; 595} 596 597//------------------------------intcon----------------------------------------- 598// Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))" 599ConINode* PhaseTransform::intcon(int i) { 600 // Small integer? Check cache! Check that cached node is not dead 601 if (i >= _icon_min && i <= _icon_max) { 602 ConINode* icon = _icons[i-_icon_min]; 603 if (icon != NULL && icon->in(TypeFunc::Control) != NULL) 604 return icon; 605 } 606 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i)); 607 assert(icon->is_Con(), ""); 608 if (i >= _icon_min && i <= _icon_max) 609 _icons[i-_icon_min] = icon; // Cache small integers 610 return icon; 611} 612 613//------------------------------longcon---------------------------------------- 614// Fast long constant. 615ConLNode* PhaseTransform::longcon(jlong l) { 616 // Small integer? Check cache! Check that cached node is not dead 617 if (l >= _lcon_min && l <= _lcon_max) { 618 ConLNode* lcon = _lcons[l-_lcon_min]; 619 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL) 620 return lcon; 621 } 622 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l)); 623 assert(lcon->is_Con(), ""); 624 if (l >= _lcon_min && l <= _lcon_max) 625 _lcons[l-_lcon_min] = lcon; // Cache small integers 626 return lcon; 627} 628 629//------------------------------zerocon----------------------------------------- 630// Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))" 631ConNode* PhaseTransform::zerocon(BasicType bt) { 632 assert((uint)bt <= _zcon_max, "domain check"); 633 ConNode* zcon = _zcons[bt]; 634 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL) 635 return zcon; 636 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt)); 637 _zcons[bt] = zcon; 638 return zcon; 639} 640 641 642 643//============================================================================= 644//------------------------------transform-------------------------------------- 645// Return a node which computes the same function as this node, but in a 646// faster or cheaper fashion. 647Node *PhaseGVN::transform( Node *n ) { 648 return transform_no_reclaim(n); 649} 650 651//------------------------------transform-------------------------------------- 652// Return a node which computes the same function as this node, but 653// in a faster or cheaper fashion. 654Node *PhaseGVN::transform_no_reclaim( Node *n ) { 655 NOT_PRODUCT( set_transforms(); ) 656 657 // Apply the Ideal call in a loop until it no longer applies 658 Node *k = n; 659 NOT_PRODUCT( uint loop_count = 0; ) 660 while( 1 ) { 661 Node *i = k->Ideal(this, /*can_reshape=*/false); 662 if( !i ) break; 663 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" ); 664 k = i; 665 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform"); 666 } 667 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } ) 668 669 670 // If brand new node, make space in type array. 671 ensure_type_or_null(k); 672 673 // Since I just called 'Value' to compute the set of run-time values 674 // for this Node, and 'Value' is non-local (and therefore expensive) I'll 675 // cache Value. Later requests for the local phase->type of this Node can 676 // use the cached Value instead of suffering with 'bottom_type'. 677 const Type *t = k->Value(this); // Get runtime Value set 678 assert(t != NULL, "value sanity"); 679 if (type_or_null(k) != t) { 680#ifndef PRODUCT 681 // Do not count initial visit to node as a transformation 682 if (type_or_null(k) == NULL) { 683 inc_new_values(); 684 set_progress(); 685 } 686#endif 687 set_type(k, t); 688 // If k is a TypeNode, capture any more-precise type permanently into Node 689 k->raise_bottom_type(t); 690 } 691 692 if( t->singleton() && !k->is_Con() ) { 693 NOT_PRODUCT( set_progress(); ) 694 return makecon(t); // Turn into a constant 695 } 696 697 // Now check for Identities 698 Node *i = k->Identity(this); // Look for a nearby replacement 699 if( i != k ) { // Found? Return replacement! 700 NOT_PRODUCT( set_progress(); ) 701 return i; 702 } 703 704 // Global Value Numbering 705 i = hash_find_insert(k); // Insert if new 706 if( i && (i != k) ) { 707 // Return the pre-existing node 708 NOT_PRODUCT( set_progress(); ) 709 return i; 710 } 711 712 // Return Idealized original 713 return k; 714} 715 716#ifdef ASSERT 717//------------------------------dead_loop_check-------------------------------- 718// Check for a simple dead loop when a data node references itself directly 719// or through an other data node excluding cons and phis. 720void PhaseGVN::dead_loop_check( Node *n ) { 721 // Phi may reference itself in a loop 722 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) { 723 // Do 2 levels check and only data inputs. 724 bool no_dead_loop = true; 725 uint cnt = n->req(); 726 for (uint i = 1; i < cnt && no_dead_loop; i++) { 727 Node *in = n->in(i); 728 if (in == n) { 729 no_dead_loop = false; 730 } else if (in != NULL && !in->is_dead_loop_safe()) { 731 uint icnt = in->req(); 732 for (uint j = 1; j < icnt && no_dead_loop; j++) { 733 if (in->in(j) == n || in->in(j) == in) 734 no_dead_loop = false; 735 } 736 } 737 } 738 if (!no_dead_loop) n->dump(3); 739 assert(no_dead_loop, "dead loop detected"); 740 } 741} 742#endif 743 744//============================================================================= 745//------------------------------PhaseIterGVN----------------------------------- 746// Initialize hash table to fresh and clean for +VerifyOpto 747PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ), 748 _delay_transform(false) { 749} 750 751//------------------------------PhaseIterGVN----------------------------------- 752// Initialize with previous PhaseIterGVN info; used by PhaseCCP 753PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn), 754 _worklist( igvn->_worklist ), 755 _delay_transform(igvn->_delay_transform) 756{ 757} 758 759//------------------------------PhaseIterGVN----------------------------------- 760// Initialize with previous PhaseGVN info from Parser 761PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn), 762 _worklist(*C->for_igvn()), 763 _delay_transform(false) 764{ 765 uint max; 766 767 // Dead nodes in the hash table inherited from GVN were not treated as 768 // roots during def-use info creation; hence they represent an invisible 769 // use. Clear them out. 770 max = _table.size(); 771 for( uint i = 0; i < max; ++i ) { 772 Node *n = _table.at(i); 773 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) { 774 if( n->is_top() ) continue; 775 assert( false, "Parse::remove_useless_nodes missed this node"); 776 hash_delete(n); 777 } 778 } 779 780 // Any Phis or Regions on the worklist probably had uses that could not 781 // make more progress because the uses were made while the Phis and Regions 782 // were in half-built states. Put all uses of Phis and Regions on worklist. 783 max = _worklist.size(); 784 for( uint j = 0; j < max; j++ ) { 785 Node *n = _worklist.at(j); 786 uint uop = n->Opcode(); 787 if( uop == Op_Phi || uop == Op_Region || 788 n->is_Type() || 789 n->is_Mem() ) 790 add_users_to_worklist(n); 791 } 792} 793 794 795#ifndef PRODUCT 796void PhaseIterGVN::verify_step(Node* n) { 797 _verify_window[_verify_counter % _verify_window_size] = n; 798 ++_verify_counter; 799 ResourceMark rm; 800 ResourceArea *area = Thread::current()->resource_area(); 801 VectorSet old_space(area), new_space(area); 802 if (C->unique() < 1000 || 803 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) { 804 ++_verify_full_passes; 805 Node::verify_recur(C->root(), -1, old_space, new_space); 806 } 807 const int verify_depth = 4; 808 for ( int i = 0; i < _verify_window_size; i++ ) { 809 Node* n = _verify_window[i]; 810 if ( n == NULL ) continue; 811 if( n->in(0) == NodeSentinel ) { // xform_idom 812 _verify_window[i] = n->in(1); 813 --i; continue; 814 } 815 // Typical fanout is 1-2, so this call visits about 6 nodes. 816 Node::verify_recur(n, verify_depth, old_space, new_space); 817 } 818} 819#endif 820 821 822//------------------------------init_worklist---------------------------------- 823// Initialize worklist for each node. 824void PhaseIterGVN::init_worklist( Node *n ) { 825 if( _worklist.member(n) ) return; 826 _worklist.push(n); 827 uint cnt = n->req(); 828 for( uint i =0 ; i < cnt; i++ ) { 829 Node *m = n->in(i); 830 if( m ) init_worklist(m); 831 } 832} 833 834//------------------------------optimize--------------------------------------- 835void PhaseIterGVN::optimize() { 836 debug_only(uint num_processed = 0;); 837#ifndef PRODUCT 838 { 839 _verify_counter = 0; 840 _verify_full_passes = 0; 841 for ( int i = 0; i < _verify_window_size; i++ ) { 842 _verify_window[i] = NULL; 843 } 844 } 845#endif 846 847 // Pull from worklist; transform node; 848 // If node has changed: update edge info and put uses on worklist. 849 while( _worklist.size() ) { 850 Node *n = _worklist.pop(); 851 if (TraceIterativeGVN && Verbose) { 852 tty->print(" Pop "); 853 NOT_PRODUCT( n->dump(); ) 854 debug_only(if( (num_processed++ % 100) == 0 ) _worklist.print_set();) 855 } 856 857 if (n->outcnt() != 0) { 858 859#ifndef PRODUCT 860 uint wlsize = _worklist.size(); 861 const Type* oldtype = type_or_null(n); 862#endif //PRODUCT 863 864 Node *nn = transform_old(n); 865 866#ifndef PRODUCT 867 if (TraceIterativeGVN) { 868 const Type* newtype = type_or_null(n); 869 if (nn != n) { 870 // print old node 871 tty->print("< "); 872 if (oldtype != newtype && oldtype != NULL) { 873 oldtype->dump(); 874 } 875 do { tty->print("\t"); } while (tty->position() < 16); 876 tty->print("<"); 877 n->dump(); 878 } 879 if (oldtype != newtype || nn != n) { 880 // print new node and/or new type 881 if (oldtype == NULL) { 882 tty->print("* "); 883 } else if (nn != n) { 884 tty->print("> "); 885 } else { 886 tty->print("= "); 887 } 888 if (newtype == NULL) { 889 tty->print("null"); 890 } else { 891 newtype->dump(); 892 } 893 do { tty->print("\t"); } while (tty->position() < 16); 894 nn->dump(); 895 } 896 if (Verbose && wlsize < _worklist.size()) { 897 tty->print(" Push {"); 898 while (wlsize != _worklist.size()) { 899 Node* pushed = _worklist.at(wlsize++); 900 tty->print(" %d", pushed->_idx); 901 } 902 tty->print_cr(" }"); 903 } 904 } 905 if( VerifyIterativeGVN && nn != n ) { 906 verify_step((Node*) NULL); // ignore n, it might be subsumed 907 } 908#endif 909 } else if (!n->is_top()) { 910 remove_dead_node(n); 911 } 912 } 913 914#ifndef PRODUCT 915 C->verify_graph_edges(); 916 if( VerifyOpto && allow_progress() ) { 917 // Must turn off allow_progress to enable assert and break recursion 918 C->root()->verify(); 919 { // Check if any progress was missed using IterGVN 920 // Def-Use info enables transformations not attempted in wash-pass 921 // e.g. Region/Phi cleanup, ... 922 // Null-check elision -- may not have reached fixpoint 923 // do not propagate to dominated nodes 924 ResourceMark rm; 925 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean! 926 // Fill worklist completely 927 igvn2.init_worklist(C->root()); 928 929 igvn2.set_allow_progress(false); 930 igvn2.optimize(); 931 igvn2.set_allow_progress(true); 932 } 933 } 934 if ( VerifyIterativeGVN && PrintOpto ) { 935 if ( _verify_counter == _verify_full_passes ) 936 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes", 937 _verify_full_passes); 938 else 939 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes", 940 _verify_counter, _verify_full_passes); 941 } 942#endif 943} 944 945 946//------------------register_new_node_with_optimizer--------------------------- 947// Register a new node with the optimizer. Update the types array, the def-use 948// info. Put on worklist. 949Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) { 950 set_type_bottom(n); 951 _worklist.push(n); 952 if (orig != NULL) C->copy_node_notes_to(n, orig); 953 return n; 954} 955 956//------------------------------transform-------------------------------------- 957// Non-recursive: idealize Node 'n' with respect to its inputs and its value 958Node *PhaseIterGVN::transform( Node *n ) { 959 if (_delay_transform) { 960 // Register the node but don't optimize for now 961 register_new_node_with_optimizer(n); 962 return n; 963 } 964 965 // If brand new node, make space in type array, and give it a type. 966 ensure_type_or_null(n); 967 if (type_or_null(n) == NULL) { 968 set_type_bottom(n); 969 } 970 971 return transform_old(n); 972} 973 974//------------------------------transform_old---------------------------------- 975Node *PhaseIterGVN::transform_old( Node *n ) { 976#ifndef PRODUCT 977 debug_only(uint loop_count = 0;); 978 set_transforms(); 979#endif 980 // Remove 'n' from hash table in case it gets modified 981 _table.hash_delete(n); 982 if( VerifyIterativeGVN ) { 983 assert( !_table.find_index(n->_idx), "found duplicate entry in table"); 984 } 985 986 // Apply the Ideal call in a loop until it no longer applies 987 Node *k = n; 988 DEBUG_ONLY(dead_loop_check(k);) 989 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);) 990 Node *i = k->Ideal(this, /*can_reshape=*/true); 991 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes"); 992#ifndef PRODUCT 993 if( VerifyIterativeGVN ) 994 verify_step(k); 995 if( i && VerifyOpto ) { 996 if( !allow_progress() ) { 997 if (i->is_Add() && i->outcnt() == 1) { 998 // Switched input to left side because this is the only use 999 } else if( i->is_If() && (i->in(0) == NULL) ) { 1000 // This IF is dead because it is dominated by an equivalent IF When 1001 // dominating if changed, info is not propagated sparsely to 'this' 1002 // Propagating this info further will spuriously identify other 1003 // progress. 1004 return i; 1005 } else 1006 set_progress(); 1007 } else 1008 set_progress(); 1009 } 1010#endif 1011 1012 while( i ) { 1013#ifndef PRODUCT 1014 debug_only( if( loop_count >= K ) i->dump(4); ) 1015 assert(loop_count < K, "infinite loop in PhaseIterGVN::transform"); 1016 debug_only( loop_count++; ) 1017#endif 1018 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes"); 1019 // Made a change; put users of original Node on worklist 1020 add_users_to_worklist( k ); 1021 // Replacing root of transform tree? 1022 if( k != i ) { 1023 // Make users of old Node now use new. 1024 subsume_node( k, i ); 1025 k = i; 1026 } 1027 DEBUG_ONLY(dead_loop_check(k);) 1028 // Try idealizing again 1029 DEBUG_ONLY(is_new = (k->outcnt() == 0);) 1030 i = k->Ideal(this, /*can_reshape=*/true); 1031 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes"); 1032#ifndef PRODUCT 1033 if( VerifyIterativeGVN ) 1034 verify_step(k); 1035 if( i && VerifyOpto ) set_progress(); 1036#endif 1037 } 1038 1039 // If brand new node, make space in type array. 1040 ensure_type_or_null(k); 1041 1042 // See what kind of values 'k' takes on at runtime 1043 const Type *t = k->Value(this); 1044 assert(t != NULL, "value sanity"); 1045 1046 // Since I just called 'Value' to compute the set of run-time values 1047 // for this Node, and 'Value' is non-local (and therefore expensive) I'll 1048 // cache Value. Later requests for the local phase->type of this Node can 1049 // use the cached Value instead of suffering with 'bottom_type'. 1050 if (t != type_or_null(k)) { 1051 NOT_PRODUCT( set_progress(); ) 1052 NOT_PRODUCT( inc_new_values();) 1053 set_type(k, t); 1054 // If k is a TypeNode, capture any more-precise type permanently into Node 1055 k->raise_bottom_type(t); 1056 // Move users of node to worklist 1057 add_users_to_worklist( k ); 1058 } 1059 1060 // If 'k' computes a constant, replace it with a constant 1061 if( t->singleton() && !k->is_Con() ) { 1062 NOT_PRODUCT( set_progress(); ) 1063 Node *con = makecon(t); // Make a constant 1064 add_users_to_worklist( k ); 1065 subsume_node( k, con ); // Everybody using k now uses con 1066 return con; 1067 } 1068 1069 // Now check for Identities 1070 i = k->Identity(this); // Look for a nearby replacement 1071 if( i != k ) { // Found? Return replacement! 1072 NOT_PRODUCT( set_progress(); ) 1073 add_users_to_worklist( k ); 1074 subsume_node( k, i ); // Everybody using k now uses i 1075 return i; 1076 } 1077 1078 // Global Value Numbering 1079 i = hash_find_insert(k); // Check for pre-existing node 1080 if( i && (i != k) ) { 1081 // Return the pre-existing node if it isn't dead 1082 NOT_PRODUCT( set_progress(); ) 1083 add_users_to_worklist( k ); 1084 subsume_node( k, i ); // Everybody using k now uses i 1085 return i; 1086 } 1087 1088 // Return Idealized original 1089 return k; 1090} 1091 1092//---------------------------------saturate------------------------------------ 1093const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type, 1094 const Type* limit_type) const { 1095 return new_type->narrow(old_type); 1096} 1097 1098//------------------------------remove_globally_dead_node---------------------- 1099// Kill a globally dead Node. All uses are also globally dead and are 1100// aggressively trimmed. 1101void PhaseIterGVN::remove_globally_dead_node( Node *dead ) { 1102 assert(dead != C->root(), "killing root, eh?"); 1103 if (dead->is_top()) return; 1104 NOT_PRODUCT( set_progress(); ) 1105 // Remove from iterative worklist 1106 _worklist.remove(dead); 1107 if (!dead->is_Con()) { // Don't kill cons but uses 1108 // Remove from hash table 1109 _table.hash_delete( dead ); 1110 // Smash all inputs to 'dead', isolating him completely 1111 for( uint i = 0; i < dead->req(); i++ ) { 1112 Node *in = dead->in(i); 1113 if( in ) { // Points to something? 1114 dead->set_req(i,NULL); // Kill the edge 1115 if (in->outcnt() == 0 && in != C->top()) {// Made input go dead? 1116 remove_dead_node(in); // Recursively remove 1117 } else if (in->outcnt() == 1 && 1118 in->has_special_unique_user()) { 1119 _worklist.push(in->unique_out()); 1120 } else if (in->outcnt() <= 2 && dead->is_Phi()) { 1121 if( in->Opcode() == Op_Region ) 1122 _worklist.push(in); 1123 else if( in->is_Store() ) { 1124 DUIterator_Fast imax, i = in->fast_outs(imax); 1125 _worklist.push(in->fast_out(i)); 1126 i++; 1127 if(in->outcnt() == 2) { 1128 _worklist.push(in->fast_out(i)); 1129 i++; 1130 } 1131 assert(!(i < imax), "sanity"); 1132 } 1133 } 1134 } 1135 } 1136 1137 if (dead->is_macro()) { 1138 C->remove_macro_node(dead); 1139 } 1140 } 1141 // Aggressively kill globally dead uses 1142 // (Cannot use DUIterator_Last because of the indefinite number 1143 // of edge deletions per loop trip.) 1144 while (dead->outcnt() > 0) { 1145 remove_globally_dead_node(dead->raw_out(0)); 1146 } 1147} 1148 1149//------------------------------subsume_node----------------------------------- 1150// Remove users from node 'old' and add them to node 'nn'. 1151void PhaseIterGVN::subsume_node( Node *old, Node *nn ) { 1152 assert( old != hash_find(old), "should already been removed" ); 1153 assert( old != C->top(), "cannot subsume top node"); 1154 // Copy debug or profile information to the new version: 1155 C->copy_node_notes_to(nn, old); 1156 // Move users of node 'old' to node 'nn' 1157 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) { 1158 Node* use = old->last_out(i); // for each use... 1159 // use might need re-hashing (but it won't if it's a new node) 1160 bool is_in_table = _table.hash_delete( use ); 1161 // Update use-def info as well 1162 // We remove all occurrences of old within use->in, 1163 // so as to avoid rehashing any node more than once. 1164 // The hash table probe swamps any outer loop overhead. 1165 uint num_edges = 0; 1166 for (uint jmax = use->len(), j = 0; j < jmax; j++) { 1167 if (use->in(j) == old) { 1168 use->set_req(j, nn); 1169 ++num_edges; 1170 } 1171 } 1172 // Insert into GVN hash table if unique 1173 // If a duplicate, 'use' will be cleaned up when pulled off worklist 1174 if( is_in_table ) { 1175 hash_find_insert(use); 1176 } 1177 i -= num_edges; // we deleted 1 or more copies of this edge 1178 } 1179 1180 // Smash all inputs to 'old', isolating him completely 1181 Node *temp = new (C, 1) Node(1); 1182 temp->init_req(0,nn); // Add a use to nn to prevent him from dying 1183 remove_dead_node( old ); 1184 temp->del_req(0); // Yank bogus edge 1185#ifndef PRODUCT 1186 if( VerifyIterativeGVN ) { 1187 for ( int i = 0; i < _verify_window_size; i++ ) { 1188 if ( _verify_window[i] == old ) 1189 _verify_window[i] = nn; 1190 } 1191 } 1192#endif 1193 _worklist.remove(temp); // this can be necessary 1194 temp->destruct(); // reuse the _idx of this little guy 1195} 1196 1197//------------------------------add_users_to_worklist-------------------------- 1198void PhaseIterGVN::add_users_to_worklist0( Node *n ) { 1199 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 1200 _worklist.push(n->fast_out(i)); // Push on worklist 1201 } 1202} 1203 1204void PhaseIterGVN::add_users_to_worklist( Node *n ) { 1205 add_users_to_worklist0(n); 1206 1207 // Move users of node to worklist 1208 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 1209 Node* use = n->fast_out(i); // Get use 1210 1211 if( use->is_Multi() || // Multi-definer? Push projs on worklist 1212 use->is_Store() ) // Enable store/load same address 1213 add_users_to_worklist0(use); 1214 1215 // If we changed the receiver type to a call, we need to revisit 1216 // the Catch following the call. It's looking for a non-NULL 1217 // receiver to know when to enable the regular fall-through path 1218 // in addition to the NullPtrException path. 1219 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) { 1220 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control); 1221 if (p != NULL) { 1222 add_users_to_worklist0(p); 1223 } 1224 } 1225 1226 if( use->is_Cmp() ) { // Enable CMP/BOOL optimization 1227 add_users_to_worklist(use); // Put Bool on worklist 1228 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the 1229 // phi merging either 0 or 1 onto the worklist 1230 if (use->outcnt() > 0) { 1231 Node* bol = use->raw_out(0); 1232 if (bol->outcnt() > 0) { 1233 Node* iff = bol->raw_out(0); 1234 if (iff->outcnt() == 2) { 1235 Node* ifproj0 = iff->raw_out(0); 1236 Node* ifproj1 = iff->raw_out(1); 1237 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) { 1238 Node* region0 = ifproj0->raw_out(0); 1239 Node* region1 = ifproj1->raw_out(0); 1240 if( region0 == region1 ) 1241 add_users_to_worklist0(region0); 1242 } 1243 } 1244 } 1245 } 1246 } 1247 1248 uint use_op = use->Opcode(); 1249 // If changed Cast input, check Phi users for simple cycles 1250 if( use->is_ConstraintCast() || use->is_CheckCastPP() ) { 1251 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) { 1252 Node* u = use->fast_out(i2); 1253 if (u->is_Phi()) 1254 _worklist.push(u); 1255 } 1256 } 1257 // If changed LShift inputs, check RShift users for useless sign-ext 1258 if( use_op == Op_LShiftI ) { 1259 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) { 1260 Node* u = use->fast_out(i2); 1261 if (u->Opcode() == Op_RShiftI) 1262 _worklist.push(u); 1263 } 1264 } 1265 // If changed AddP inputs, check Stores for loop invariant 1266 if( use_op == Op_AddP ) { 1267 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) { 1268 Node* u = use->fast_out(i2); 1269 if (u->is_Mem()) 1270 _worklist.push(u); 1271 } 1272 } 1273 // If changed initialization activity, check dependent Stores 1274 if (use_op == Op_Allocate || use_op == Op_AllocateArray) { 1275 InitializeNode* init = use->as_Allocate()->initialization(); 1276 if (init != NULL) { 1277 Node* imem = init->proj_out(TypeFunc::Memory); 1278 if (imem != NULL) add_users_to_worklist0(imem); 1279 } 1280 } 1281 if (use_op == Op_Initialize) { 1282 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory); 1283 if (imem != NULL) add_users_to_worklist0(imem); 1284 } 1285 } 1286} 1287 1288//============================================================================= 1289#ifndef PRODUCT 1290uint PhaseCCP::_total_invokes = 0; 1291uint PhaseCCP::_total_constants = 0; 1292#endif 1293//------------------------------PhaseCCP--------------------------------------- 1294// Conditional Constant Propagation, ala Wegman & Zadeck 1295PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) { 1296 NOT_PRODUCT( clear_constants(); ) 1297 assert( _worklist.size() == 0, "" ); 1298 // Clear out _nodes from IterGVN. Must be clear to transform call. 1299 _nodes.clear(); // Clear out from IterGVN 1300 analyze(); 1301} 1302 1303#ifndef PRODUCT 1304//------------------------------~PhaseCCP-------------------------------------- 1305PhaseCCP::~PhaseCCP() { 1306 inc_invokes(); 1307 _total_constants += count_constants(); 1308} 1309#endif 1310 1311 1312#ifdef ASSERT 1313static bool ccp_type_widens(const Type* t, const Type* t0) { 1314 assert(t->meet(t0) == t, "Not monotonic"); 1315 switch (t->base() == t0->base() ? t->base() : Type::Top) { 1316 case Type::Int: 1317 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases"); 1318 break; 1319 case Type::Long: 1320 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases"); 1321 break; 1322 } 1323 return true; 1324} 1325#endif //ASSERT 1326 1327//------------------------------analyze---------------------------------------- 1328void PhaseCCP::analyze() { 1329 // Initialize all types to TOP, optimistic analysis 1330 for (int i = C->unique() - 1; i >= 0; i--) { 1331 _types.map(i,Type::TOP); 1332 } 1333 1334 // Push root onto worklist 1335 Unique_Node_List worklist; 1336 worklist.push(C->root()); 1337 1338 // Pull from worklist; compute new value; push changes out. 1339 // This loop is the meat of CCP. 1340 while( worklist.size() ) { 1341 Node *n = worklist.pop(); 1342 const Type *t = n->Value(this); 1343 if (t != type(n)) { 1344 assert(ccp_type_widens(t, type(n)), "ccp type must widen"); 1345#ifndef PRODUCT 1346 if( TracePhaseCCP ) { 1347 t->dump(); 1348 do { tty->print("\t"); } while (tty->position() < 16); 1349 n->dump(); 1350 } 1351#endif 1352 set_type(n, t); 1353 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { 1354 Node* m = n->fast_out(i); // Get user 1355 if( m->is_Region() ) { // New path to Region? Must recheck Phis too 1356 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) { 1357 Node* p = m->fast_out(i2); // Propagate changes to uses 1358 if( p->bottom_type() != type(p) ) // If not already bottomed out 1359 worklist.push(p); // Propagate change to user 1360 } 1361 } 1362 // If we changed the receiver type to a call, we need to revisit 1363 // the Catch following the call. It's looking for a non-NULL 1364 // receiver to know when to enable the regular fall-through path 1365 // in addition to the NullPtrException path 1366 if (m->is_Call()) { 1367 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) { 1368 Node* p = m->fast_out(i2); // Propagate changes to uses 1369 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1) 1370 worklist.push(p->unique_out()); 1371 } 1372 } 1373 if( m->bottom_type() != type(m) ) // If not already bottomed out 1374 worklist.push(m); // Propagate change to user 1375 } 1376 } 1377 } 1378} 1379 1380//------------------------------do_transform----------------------------------- 1381// Top level driver for the recursive transformer 1382void PhaseCCP::do_transform() { 1383 // Correct leaves of new-space Nodes; they point to old-space. 1384 C->set_root( transform(C->root())->as_Root() ); 1385 assert( C->top(), "missing TOP node" ); 1386 assert( C->root(), "missing root" ); 1387} 1388 1389//------------------------------transform-------------------------------------- 1390// Given a Node in old-space, clone him into new-space. 1391// Convert any of his old-space children into new-space children. 1392Node *PhaseCCP::transform( Node *n ) { 1393 Node *new_node = _nodes[n->_idx]; // Check for transformed node 1394 if( new_node != NULL ) 1395 return new_node; // Been there, done that, return old answer 1396 new_node = transform_once(n); // Check for constant 1397 _nodes.map( n->_idx, new_node ); // Flag as having been cloned 1398 1399 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc 1400 GrowableArray <Node *> trstack(C->unique() >> 1); 1401 1402 trstack.push(new_node); // Process children of cloned node 1403 while ( trstack.is_nonempty() ) { 1404 Node *clone = trstack.pop(); 1405 uint cnt = clone->req(); 1406 for( uint i = 0; i < cnt; i++ ) { // For all inputs do 1407 Node *input = clone->in(i); 1408 if( input != NULL ) { // Ignore NULLs 1409 Node *new_input = _nodes[input->_idx]; // Check for cloned input node 1410 if( new_input == NULL ) { 1411 new_input = transform_once(input); // Check for constant 1412 _nodes.map( input->_idx, new_input );// Flag as having been cloned 1413 trstack.push(new_input); 1414 } 1415 assert( new_input == clone->in(i), "insanity check"); 1416 } 1417 } 1418 } 1419 return new_node; 1420} 1421 1422 1423//------------------------------transform_once--------------------------------- 1424// For PhaseCCP, transformation is IDENTITY unless Node computed a constant. 1425Node *PhaseCCP::transform_once( Node *n ) { 1426 const Type *t = type(n); 1427 // Constant? Use constant Node instead 1428 if( t->singleton() ) { 1429 Node *nn = n; // Default is to return the original constant 1430 if( t == Type::TOP ) { 1431 // cache my top node on the Compile instance 1432 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) { 1433 C->set_cached_top_node( ConNode::make(C, Type::TOP) ); 1434 set_type(C->top(), Type::TOP); 1435 } 1436 nn = C->top(); 1437 } 1438 if( !n->is_Con() ) { 1439 if( t != Type::TOP ) { 1440 nn = makecon(t); // ConNode::make(t); 1441 NOT_PRODUCT( inc_constants(); ) 1442 } else if( n->is_Region() ) { // Unreachable region 1443 // Note: nn == C->top() 1444 n->set_req(0, NULL); // Cut selfreference 1445 // Eagerly remove dead phis to avoid phis copies creation. 1446 for (DUIterator i = n->outs(); n->has_out(i); i++) { 1447 Node* m = n->out(i); 1448 if( m->is_Phi() ) { 1449 assert(type(m) == Type::TOP, "Unreachable region should not have live phis."); 1450 add_users_to_worklist(m); 1451 hash_delete(m); // Yank from hash before hacking edges 1452 subsume_node(m, nn); 1453 --i; // deleted this phi; rescan starting with next position 1454 } 1455 } 1456 } 1457 add_users_to_worklist(n); // Users of about-to-be-constant 'n' 1458 hash_delete(n); // Removed 'n' from table before subsuming it 1459 subsume_node(n,nn); // Update DefUse edges for new constant 1460 } 1461 return nn; 1462 } 1463 1464 // If x is a TypeNode, capture any more-precise type permanently into Node 1465 if (t != n->bottom_type()) { 1466 hash_delete(n); // changing bottom type may force a rehash 1467 n->raise_bottom_type(t); 1468 _worklist.push(n); // n re-enters the hash table via the worklist 1469 } 1470 1471 // Idealize graph using DU info. Must clone() into new-space. 1472 // DU info is generally used to show profitability, progress or safety 1473 // (but generally not needed for correctness). 1474 Node *nn = n->Ideal_DU_postCCP(this); 1475 1476 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks 1477 switch( n->Opcode() ) { 1478 case Op_FastLock: // Revisit FastLocks for lock coarsening 1479 case Op_If: 1480 case Op_CountedLoopEnd: 1481 case Op_Region: 1482 case Op_Loop: 1483 case Op_CountedLoop: 1484 case Op_Conv2B: 1485 case Op_Opaque1: 1486 case Op_Opaque2: 1487 _worklist.push(n); 1488 break; 1489 default: 1490 break; 1491 } 1492 if( nn ) { 1493 _worklist.push(n); 1494 // Put users of 'n' onto worklist for second igvn transform 1495 add_users_to_worklist(n); 1496 return nn; 1497 } 1498 1499 return n; 1500} 1501 1502//---------------------------------saturate------------------------------------ 1503const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type, 1504 const Type* limit_type) const { 1505 const Type* wide_type = new_type->widen(old_type, limit_type); 1506 if (wide_type != new_type) { // did we widen? 1507 // If so, we may have widened beyond the limit type. Clip it back down. 1508 new_type = wide_type->filter(limit_type); 1509 } 1510 return new_type; 1511} 1512 1513//------------------------------print_statistics------------------------------- 1514#ifndef PRODUCT 1515void PhaseCCP::print_statistics() { 1516 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants); 1517} 1518#endif 1519 1520 1521//============================================================================= 1522#ifndef PRODUCT 1523uint PhasePeephole::_total_peepholes = 0; 1524#endif 1525//------------------------------PhasePeephole---------------------------------- 1526// Conditional Constant Propagation, ala Wegman & Zadeck 1527PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg ) 1528 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) { 1529 NOT_PRODUCT( clear_peepholes(); ) 1530} 1531 1532#ifndef PRODUCT 1533//------------------------------~PhasePeephole--------------------------------- 1534PhasePeephole::~PhasePeephole() { 1535 _total_peepholes += count_peepholes(); 1536} 1537#endif 1538 1539//------------------------------transform-------------------------------------- 1540Node *PhasePeephole::transform( Node *n ) { 1541 ShouldNotCallThis(); 1542 return NULL; 1543} 1544 1545//------------------------------do_transform----------------------------------- 1546void PhasePeephole::do_transform() { 1547 bool method_name_not_printed = true; 1548 1549 // Examine each basic block 1550 for( uint block_number = 1; block_number < _cfg._num_blocks; ++block_number ) { 1551 Block *block = _cfg._blocks[block_number]; 1552 bool block_not_printed = true; 1553 1554 // and each instruction within a block 1555 uint end_index = block->_nodes.size(); 1556 // block->end_idx() not valid after PhaseRegAlloc 1557 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) { 1558 Node *n = block->_nodes.at(instruction_index); 1559 if( n->is_Mach() ) { 1560 MachNode *m = n->as_Mach(); 1561 int deleted_count = 0; 1562 // check for peephole opportunities 1563 MachNode *m2 = m->peephole( block, instruction_index, _regalloc, deleted_count, C ); 1564 if( m2 != NULL ) { 1565#ifndef PRODUCT 1566 if( PrintOptoPeephole ) { 1567 // Print method, first time only 1568 if( C->method() && method_name_not_printed ) { 1569 C->method()->print_short_name(); tty->cr(); 1570 method_name_not_printed = false; 1571 } 1572 // Print this block 1573 if( Verbose && block_not_printed) { 1574 tty->print_cr("in block"); 1575 block->dump(); 1576 block_not_printed = false; 1577 } 1578 // Print instructions being deleted 1579 for( int i = (deleted_count - 1); i >= 0; --i ) { 1580 block->_nodes.at(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr(); 1581 } 1582 tty->print_cr("replaced with"); 1583 // Print new instruction 1584 m2->format(_regalloc); 1585 tty->print("\n\n"); 1586 } 1587#endif 1588 // Remove old nodes from basic block and update instruction_index 1589 // (old nodes still exist and may have edges pointing to them 1590 // as register allocation info is stored in the allocator using 1591 // the node index to live range mappings.) 1592 uint safe_instruction_index = (instruction_index - deleted_count); 1593 for( ; (instruction_index > safe_instruction_index); --instruction_index ) { 1594 block->_nodes.remove( instruction_index ); 1595 } 1596 // install new node after safe_instruction_index 1597 block->_nodes.insert( safe_instruction_index + 1, m2 ); 1598 end_index = block->_nodes.size() - 1; // Recompute new block size 1599 NOT_PRODUCT( inc_peepholes(); ) 1600 } 1601 } 1602 } 1603 } 1604} 1605 1606//------------------------------print_statistics------------------------------- 1607#ifndef PRODUCT 1608void PhasePeephole::print_statistics() { 1609 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes); 1610} 1611#endif 1612 1613 1614//============================================================================= 1615//------------------------------set_req_X-------------------------------------- 1616void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) { 1617 assert( is_not_dead(n), "can not use dead node"); 1618 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" ); 1619 Node *old = in(i); 1620 set_req(i, n); 1621 1622 // old goes dead? 1623 if( old ) { 1624 switch (old->outcnt()) { 1625 case 0: 1626 // Put into the worklist to kill later. We do not kill it now because the 1627 // recursive kill will delete the current node (this) if dead-loop exists 1628 if (!old->is_top()) 1629 igvn->_worklist.push( old ); 1630 break; 1631 case 1: 1632 if( old->is_Store() || old->has_special_unique_user() ) 1633 igvn->add_users_to_worklist( old ); 1634 break; 1635 case 2: 1636 if( old->is_Store() ) 1637 igvn->add_users_to_worklist( old ); 1638 if( old->Opcode() == Op_Region ) 1639 igvn->_worklist.push(old); 1640 break; 1641 case 3: 1642 if( old->Opcode() == Op_Region ) { 1643 igvn->_worklist.push(old); 1644 igvn->add_users_to_worklist( old ); 1645 } 1646 break; 1647 default: 1648 break; 1649 } 1650 } 1651 1652} 1653 1654//-------------------------------replace_by----------------------------------- 1655// Using def-use info, replace one node for another. Follow the def-use info 1656// to all users of the OLD node. Then make all uses point to the NEW node. 1657void Node::replace_by(Node *new_node) { 1658 assert(!is_top(), "top node has no DU info"); 1659 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) { 1660 Node* use = last_out(i); 1661 uint uses_found = 0; 1662 for (uint j = 0; j < use->len(); j++) { 1663 if (use->in(j) == this) { 1664 if (j < use->req()) 1665 use->set_req(j, new_node); 1666 else use->set_prec(j, new_node); 1667 uses_found++; 1668 } 1669 } 1670 i -= uses_found; // we deleted 1 or more copies of this edge 1671 } 1672} 1673 1674//============================================================================= 1675//----------------------------------------------------------------------------- 1676void Type_Array::grow( uint i ) { 1677 if( !_max ) { 1678 _max = 1; 1679 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) ); 1680 _types[0] = NULL; 1681 } 1682 uint old = _max; 1683 while( i >= _max ) _max <<= 1; // Double to fit 1684 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*)); 1685 memset( &_types[old], 0, (_max-old)*sizeof(Type*) ); 1686} 1687 1688//------------------------------dump------------------------------------------- 1689#ifndef PRODUCT 1690void Type_Array::dump() const { 1691 uint max = Size(); 1692 for( uint i = 0; i < max; i++ ) { 1693 if( _types[i] != NULL ) { 1694 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr(); 1695 } 1696 } 1697} 1698#endif 1699