1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "opto/block.hpp"
28 #include "opto/callnode.hpp"
29 #include "opto/cfgnode.hpp"
30 #include "opto/idealGraphPrinter.hpp"
31 #include "opto/loopnode.hpp"
32 #include "opto/machnode.hpp"
33 #include "opto/opcodes.hpp"
34 #include "opto/phaseX.hpp"
35 #include "opto/regalloc.hpp"
36 #include "opto/rootnode.hpp"
37
38 //=============================================================================
39 #define NODE_HASH_MINIMUM_SIZE 255
40 //------------------------------NodeHash---------------------------------------
41 NodeHash::NodeHash(uint est_max_size) :
42 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
43 _a(Thread::current()->resource_area()),
44 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ),
45 _inserts(0), _insert_limit( insert_limit() ),
46 _look_probes(0), _lookup_hits(0), _lookup_misses(0),
47 _total_insert_probes(0), _total_inserts(0),
48 _insert_probes(0), _grows(0) {
49 // _sentinel must be in the current node space
50 _sentinel = new (Compile::current()) ProjNode(NULL, TypeFunc::Control);
51 memset(_table,0,sizeof(Node*)*_max);
52 }
53
54 //------------------------------NodeHash---------------------------------------
55 NodeHash::NodeHash(Arena *arena, uint est_max_size) :
56 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
57 _a(arena),
58 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ),
59 _inserts(0), _insert_limit( insert_limit() ),
60 _look_probes(0), _lookup_hits(0), _lookup_misses(0),
61 _delete_probes(0), _delete_hits(0), _delete_misses(0),
62 _total_insert_probes(0), _total_inserts(0),
63 _insert_probes(0), _grows(0) {
64 // _sentinel must be in the current node space
65 _sentinel = new (Compile::current()) ProjNode(NULL, TypeFunc::Control);
66 memset(_table,0,sizeof(Node*)*_max);
67 }
68
69 //------------------------------NodeHash---------------------------------------
70 NodeHash::NodeHash(NodeHash *nh) {
71 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
72 // just copy in all the fields
73 *this = *nh;
74 // nh->_sentinel must be in the current node space
75 }
76
77 void NodeHash::replace_with(NodeHash *nh) {
78 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
79 // just copy in all the fields
80 *this = *nh;
81 // nh->_sentinel must be in the current node space
82 }
83
84 //------------------------------hash_find--------------------------------------
85 // Find in hash table
86 Node *NodeHash::hash_find( const Node *n ) {
87 // ((Node*)n)->set_hash( n->hash() );
88 uint hash = n->hash();
89 if (hash == Node::NO_HASH) {
90 debug_only( _lookup_misses++ );
91 return NULL;
92 }
93 uint key = hash & (_max-1);
94 uint stride = key | 0x01;
95 debug_only( _look_probes++ );
96 Node *k = _table[key]; // Get hashed value
97 if( !k ) { // ?Miss?
98 debug_only( _lookup_misses++ );
99 return NULL; // Miss!
100 }
101
102 int op = n->Opcode();
103 uint req = n->req();
104 while( 1 ) { // While probing hash table
105 if( k->req() == req && // Same count of inputs
106 k->Opcode() == op ) { // Same Opcode
107 for( uint i=0; i<req; i++ )
108 if( n->in(i)!=k->in(i)) // Different inputs?
109 goto collision; // "goto" is a speed hack...
110 if( n->cmp(*k) ) { // Check for any special bits
111 debug_only( _lookup_hits++ );
112 return k; // Hit!
113 }
114 }
115 collision:
116 debug_only( _look_probes++ );
117 key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime
118 k = _table[key]; // Get hashed value
119 if( !k ) { // ?Miss?
120 debug_only( _lookup_misses++ );
121 return NULL; // Miss!
122 }
123 }
124 ShouldNotReachHere();
125 return NULL;
126 }
127
128 //------------------------------hash_find_insert-------------------------------
129 // Find in hash table, insert if not already present
130 // Used to preserve unique entries in hash table
131 Node *NodeHash::hash_find_insert( Node *n ) {
132 // n->set_hash( );
133 uint hash = n->hash();
134 if (hash == Node::NO_HASH) {
135 debug_only( _lookup_misses++ );
136 return NULL;
137 }
138 uint key = hash & (_max-1);
139 uint stride = key | 0x01; // stride must be relatively prime to table siz
140 uint first_sentinel = 0; // replace a sentinel if seen.
141 debug_only( _look_probes++ );
142 Node *k = _table[key]; // Get hashed value
143 if( !k ) { // ?Miss?
144 debug_only( _lookup_misses++ );
145 _table[key] = n; // Insert into table!
146 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
147 check_grow(); // Grow table if insert hit limit
148 return NULL; // Miss!
149 }
150 else if( k == _sentinel ) {
151 first_sentinel = key; // Can insert here
152 }
153
154 int op = n->Opcode();
155 uint req = n->req();
156 while( 1 ) { // While probing hash table
157 if( k->req() == req && // Same count of inputs
158 k->Opcode() == op ) { // Same Opcode
159 for( uint i=0; i<req; i++ )
160 if( n->in(i)!=k->in(i)) // Different inputs?
161 goto collision; // "goto" is a speed hack...
162 if( n->cmp(*k) ) { // Check for any special bits
163 debug_only( _lookup_hits++ );
164 return k; // Hit!
165 }
166 }
167 collision:
168 debug_only( _look_probes++ );
169 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
170 k = _table[key]; // Get hashed value
171 if( !k ) { // ?Miss?
172 debug_only( _lookup_misses++ );
173 key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel?
174 _table[key] = n; // Insert into table!
175 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
176 check_grow(); // Grow table if insert hit limit
177 return NULL; // Miss!
178 }
179 else if( first_sentinel == 0 && k == _sentinel ) {
180 first_sentinel = key; // Can insert here
181 }
182
183 }
184 ShouldNotReachHere();
185 return NULL;
186 }
187
188 //------------------------------hash_insert------------------------------------
189 // Insert into hash table
190 void NodeHash::hash_insert( Node *n ) {
191 // // "conflict" comments -- print nodes that conflict
192 // bool conflict = false;
193 // n->set_hash();
194 uint hash = n->hash();
195 if (hash == Node::NO_HASH) {
196 return;
197 }
198 check_grow();
199 uint key = hash & (_max-1);
200 uint stride = key | 0x01;
201
202 while( 1 ) { // While probing hash table
203 debug_only( _insert_probes++ );
204 Node *k = _table[key]; // Get hashed value
205 if( !k || (k == _sentinel) ) break; // Found a slot
206 assert( k != n, "already inserted" );
207 // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; }
208 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
209 }
210 _table[key] = n; // Insert into table!
211 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
212 // if( conflict ) { n->dump(); }
213 }
214
215 //------------------------------hash_delete------------------------------------
216 // Replace in hash table with sentinel
217 bool NodeHash::hash_delete( const Node *n ) {
218 Node *k;
219 uint hash = n->hash();
220 if (hash == Node::NO_HASH) {
221 debug_only( _delete_misses++ );
222 return false;
223 }
224 uint key = hash & (_max-1);
225 uint stride = key | 0x01;
226 debug_only( uint counter = 0; );
227 for( ; /* (k != NULL) && (k != _sentinel) */; ) {
228 debug_only( counter++ );
229 debug_only( _delete_probes++ );
230 k = _table[key]; // Get hashed value
231 if( !k ) { // Miss?
232 debug_only( _delete_misses++ );
233 #ifdef ASSERT
234 if( VerifyOpto ) {
235 for( uint i=0; i < _max; i++ )
236 assert( _table[i] != n, "changed edges with rehashing" );
237 }
238 #endif
239 return false; // Miss! Not in chain
240 }
241 else if( n == k ) {
242 debug_only( _delete_hits++ );
243 _table[key] = _sentinel; // Hit! Label as deleted entry
244 debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table.
245 return true;
246 }
247 else {
248 // collision: move through table with prime offset
249 key = (key + stride/*7*/) & (_max-1);
250 assert( counter <= _insert_limit, "Cycle in hash-table");
251 }
252 }
253 ShouldNotReachHere();
254 return false;
255 }
256
257 //------------------------------round_up---------------------------------------
258 // Round up to nearest power of 2
259 uint NodeHash::round_up( uint x ) {
260 x += (x>>2); // Add 25% slop
261 if( x <16 ) return 16; // Small stuff
262 uint i=16;
263 while( i < x ) i <<= 1; // Double to fit
264 return i; // Return hash table size
265 }
266
267 //------------------------------grow-------------------------------------------
268 // Grow _table to next power of 2 and insert old entries
269 void NodeHash::grow() {
270 // Record old state
271 uint old_max = _max;
272 Node **old_table = _table;
273 // Construct new table with twice the space
274 _grows++;
275 _total_inserts += _inserts;
276 _total_insert_probes += _insert_probes;
277 _inserts = 0;
278 _insert_probes = 0;
279 _max = _max << 1;
280 _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) );
281 memset(_table,0,sizeof(Node*)*_max);
282 _insert_limit = insert_limit();
283 // Insert old entries into the new table
284 for( uint i = 0; i < old_max; i++ ) {
285 Node *m = *old_table++;
286 if( !m || m == _sentinel ) continue;
287 debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table.
288 hash_insert(m);
289 }
290 }
291
292 //------------------------------clear------------------------------------------
293 // Clear all entries in _table to NULL but keep storage
294 void NodeHash::clear() {
295 #ifdef ASSERT
296 // Unlock all nodes upon removal from table.
297 for (uint i = 0; i < _max; i++) {
298 Node* n = _table[i];
299 if (!n || n == _sentinel) continue;
300 n->exit_hash_lock();
301 }
302 #endif
303
304 memset( _table, 0, _max * sizeof(Node*) );
305 }
306
307 //-----------------------remove_useless_nodes----------------------------------
308 // Remove useless nodes from value table,
309 // implementation does not depend on hash function
310 void NodeHash::remove_useless_nodes(VectorSet &useful) {
311
312 // Dead nodes in the hash table inherited from GVN should not replace
313 // existing nodes, remove dead nodes.
314 uint max = size();
315 Node *sentinel_node = sentinel();
316 for( uint i = 0; i < max; ++i ) {
317 Node *n = at(i);
318 if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) {
319 debug_only(n->exit_hash_lock()); // Unlock the node when removed
320 _table[i] = sentinel_node; // Replace with placeholder
321 }
322 }
323 }
324
325
326 void NodeHash::check_no_speculative_types() {
327 #ifdef ASSERT
328 uint max = size();
329 Node *sentinel_node = sentinel();
330 for (uint i = 0; i < max; ++i) {
331 Node *n = at(i);
332 if(n != NULL && n != sentinel_node && n->is_Type()) {
333 TypeNode* tn = n->as_Type();
334 const Type* t = tn->type();
335 const Type* t_no_spec = t->remove_speculative();
336 assert(t == t_no_spec, "dead node in hash table or missed node during speculative cleanup");
337 }
338 }
339 #endif
340 }
341
342 #ifndef PRODUCT
343 //------------------------------dump-------------------------------------------
344 // Dump statistics for the hash table
345 void NodeHash::dump() {
346 _total_inserts += _inserts;
347 _total_insert_probes += _insert_probes;
348 if (PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0)) {
349 if (WizardMode) {
350 for (uint i=0; i<_max; i++) {
351 if (_table[i])
352 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
353 }
354 }
355 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max);
356 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
357 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
358 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
359 // sentinels increase lookup cost, but not insert cost
360 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
361 assert( _inserts+(_inserts>>3) < _max, "table too full" );
362 assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
363 }
364 }
365
366 Node *NodeHash::find_index(uint idx) { // For debugging
367 // Find an entry by its index value
368 for( uint i = 0; i < _max; i++ ) {
369 Node *m = _table[i];
370 if( !m || m == _sentinel ) continue;
371 if( m->_idx == (uint)idx ) return m;
372 }
373 return NULL;
374 }
375 #endif
376
377 #ifdef ASSERT
378 NodeHash::~NodeHash() {
379 // Unlock all nodes upon destruction of table.
380 if (_table != (Node**)badAddress) clear();
381 }
382
383 void NodeHash::operator=(const NodeHash& nh) {
384 // Unlock all nodes upon replacement of table.
385 if (&nh == this) return;
386 if (_table != (Node**)badAddress) clear();
387 memcpy(this, &nh, sizeof(*this));
388 // Do not increment hash_lock counts again.
389 // Instead, be sure we never again use the source table.
390 ((NodeHash*)&nh)->_table = (Node**)badAddress;
391 }
392
393
394 #endif
395
396
397 //=============================================================================
398 //------------------------------PhaseRemoveUseless-----------------------------
399 // 1) Use a breadthfirst walk to collect useful nodes reachable from root.
400 PhaseRemoveUseless::PhaseRemoveUseless( PhaseGVN *gvn, Unique_Node_List *worklist ) : Phase(Remove_Useless),
401 _useful(Thread::current()->resource_area()) {
402
403 // Implementation requires 'UseLoopSafepoints == true' and an edge from root
404 // to each SafePointNode at a backward branch. Inserted in add_safepoint().
405 if( !UseLoopSafepoints || !OptoRemoveUseless ) return;
406
407 // Identify nodes that are reachable from below, useful.
408 C->identify_useful_nodes(_useful);
409 // Update dead node list
410 C->update_dead_node_list(_useful);
411
412 // Remove all useless nodes from PhaseValues' recorded types
413 // Must be done before disconnecting nodes to preserve hash-table-invariant
414 gvn->remove_useless_nodes(_useful.member_set());
415
416 // Remove all useless nodes from future worklist
417 worklist->remove_useless_nodes(_useful.member_set());
418
419 // Disconnect 'useless' nodes that are adjacent to useful nodes
420 C->remove_useless_nodes(_useful);
421
422 // Remove edges from "root" to each SafePoint at a backward branch.
423 // They were inserted during parsing (see add_safepoint()) to make infinite
424 // loops without calls or exceptions visible to root, i.e., useful.
425 Node *root = C->root();
426 if( root != NULL ) {
427 for( uint i = root->req(); i < root->len(); ++i ) {
428 Node *n = root->in(i);
429 if( n != NULL && n->is_SafePoint() ) {
430 root->rm_prec(i);
431 --i;
432 }
433 }
434 }
435 }
436
437
438 //=============================================================================
439 //------------------------------PhaseTransform---------------------------------
440 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
441 _arena(Thread::current()->resource_area()),
442 _nodes(_arena),
443 _types(_arena)
444 {
445 init_con_caches();
446 #ifndef PRODUCT
447 clear_progress();
448 clear_transforms();
449 set_allow_progress(true);
450 #endif
451 // Force allocation for currently existing nodes
452 _types.map(C->unique(), NULL);
453 }
454
455 //------------------------------PhaseTransform---------------------------------
456 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
457 _arena(arena),
458 _nodes(arena),
459 _types(arena)
460 {
461 init_con_caches();
462 #ifndef PRODUCT
463 clear_progress();
464 clear_transforms();
465 set_allow_progress(true);
466 #endif
467 // Force allocation for currently existing nodes
468 _types.map(C->unique(), NULL);
469 }
470
471 //------------------------------PhaseTransform---------------------------------
472 // Initialize with previously generated type information
473 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
474 _arena(pt->_arena),
475 _nodes(pt->_nodes),
476 _types(pt->_types)
477 {
478 init_con_caches();
479 #ifndef PRODUCT
480 clear_progress();
481 clear_transforms();
482 set_allow_progress(true);
483 #endif
484 }
485
486 void PhaseTransform::init_con_caches() {
487 memset(_icons,0,sizeof(_icons));
488 memset(_lcons,0,sizeof(_lcons));
489 memset(_zcons,0,sizeof(_zcons));
490 }
491
492
493 //--------------------------------find_int_type--------------------------------
494 const TypeInt* PhaseTransform::find_int_type(Node* n) {
495 if (n == NULL) return NULL;
496 // Call type_or_null(n) to determine node's type since we might be in
497 // parse phase and call n->Value() may return wrong type.
498 // (For example, a phi node at the beginning of loop parsing is not ready.)
499 const Type* t = type_or_null(n);
500 if (t == NULL) return NULL;
501 return t->isa_int();
502 }
503
504
505 //-------------------------------find_long_type--------------------------------
506 const TypeLong* PhaseTransform::find_long_type(Node* n) {
507 if (n == NULL) return NULL;
508 // (See comment above on type_or_null.)
509 const Type* t = type_or_null(n);
510 if (t == NULL) return NULL;
511 return t->isa_long();
512 }
513
514
515 #ifndef PRODUCT
516 void PhaseTransform::dump_old2new_map() const {
517 _nodes.dump();
518 }
519
520 void PhaseTransform::dump_new( uint nidx ) const {
521 for( uint i=0; i<_nodes.Size(); i++ )
522 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
523 _nodes[i]->dump();
524 tty->cr();
525 tty->print_cr("Old index= %d",i);
526 return;
527 }
528 tty->print_cr("Node %d not found in the new indices", nidx);
529 }
530
531 //------------------------------dump_types-------------------------------------
532 void PhaseTransform::dump_types( ) const {
533 _types.dump();
534 }
535
536 //------------------------------dump_nodes_and_types---------------------------
537 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
538 VectorSet visited(Thread::current()->resource_area());
539 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
540 }
541
542 //------------------------------dump_nodes_and_types_recur---------------------
543 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
544 if( !n ) return;
545 if( depth == 0 ) return;
546 if( visited.test_set(n->_idx) ) return;
547 for( uint i=0; i<n->len(); i++ ) {
548 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
549 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
550 }
551 n->dump();
552 if (type_or_null(n) != NULL) {
553 tty->print(" "); type(n)->dump(); tty->cr();
554 }
555 }
556
557 #endif
558
559
560 //=============================================================================
561 //------------------------------PhaseValues------------------------------------
562 // Set minimum table size to "255"
563 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
564 NOT_PRODUCT( clear_new_values(); )
565 }
566
567 //------------------------------PhaseValues------------------------------------
568 // Set minimum table size to "255"
569 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
570 _table(&ptv->_table) {
571 NOT_PRODUCT( clear_new_values(); )
572 }
573
574 //------------------------------PhaseValues------------------------------------
575 // Used by +VerifyOpto. Clear out hash table but copy _types array.
576 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
577 _table(ptv->arena(),ptv->_table.size()) {
578 NOT_PRODUCT( clear_new_values(); )
579 }
580
581 //------------------------------~PhaseValues-----------------------------------
582 #ifndef PRODUCT
583 PhaseValues::~PhaseValues() {
584 _table.dump();
585
586 // Statistics for value progress and efficiency
587 if( PrintCompilation && Verbose && WizardMode ) {
588 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
589 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
590 if( made_transforms() != 0 ) {
591 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
592 } else {
593 tty->cr();
594 }
595 }
596 }
597 #endif
598
599 //------------------------------makecon----------------------------------------
600 ConNode* PhaseTransform::makecon(const Type *t) {
601 assert(t->singleton(), "must be a constant");
602 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
603 switch (t->base()) { // fast paths
604 case Type::Half:
605 case Type::Top: return (ConNode*) C->top();
606 case Type::Int: return intcon( t->is_int()->get_con() );
607 case Type::Long: return longcon( t->is_long()->get_con() );
608 }
609 if (t->is_zero_type())
610 return zerocon(t->basic_type());
611 return uncached_makecon(t);
612 }
613
614 //--------------------------uncached_makecon-----------------------------------
615 // Make an idealized constant - one of ConINode, ConPNode, etc.
616 ConNode* PhaseValues::uncached_makecon(const Type *t) {
617 assert(t->singleton(), "must be a constant");
618 ConNode* x = ConNode::make(C, t);
619 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
620 if (k == NULL) {
621 set_type(x, t); // Missed, provide type mapping
622 GrowableArray<Node_Notes*>* nna = C->node_note_array();
623 if (nna != NULL) {
624 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
625 loc->clear(); // do not put debug info on constants
626 }
627 } else {
628 x->destruct(); // Hit, destroy duplicate constant
629 x = k; // use existing constant
630 }
631 return x;
632 }
633
634 //------------------------------intcon-----------------------------------------
635 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
636 ConINode* PhaseTransform::intcon(int i) {
637 // Small integer? Check cache! Check that cached node is not dead
638 if (i >= _icon_min && i <= _icon_max) {
639 ConINode* icon = _icons[i-_icon_min];
640 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
641 return icon;
642 }
643 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
644 assert(icon->is_Con(), "");
645 if (i >= _icon_min && i <= _icon_max)
646 _icons[i-_icon_min] = icon; // Cache small integers
647 return icon;
648 }
649
650 //------------------------------longcon----------------------------------------
651 // Fast long constant.
652 ConLNode* PhaseTransform::longcon(jlong l) {
653 // Small integer? Check cache! Check that cached node is not dead
654 if (l >= _lcon_min && l <= _lcon_max) {
655 ConLNode* lcon = _lcons[l-_lcon_min];
656 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
657 return lcon;
658 }
659 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
660 assert(lcon->is_Con(), "");
661 if (l >= _lcon_min && l <= _lcon_max)
662 _lcons[l-_lcon_min] = lcon; // Cache small integers
663 return lcon;
664 }
665
666 //------------------------------zerocon-----------------------------------------
667 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
668 ConNode* PhaseTransform::zerocon(BasicType bt) {
669 assert((uint)bt <= _zcon_max, "domain check");
670 ConNode* zcon = _zcons[bt];
671 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
672 return zcon;
673 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
674 _zcons[bt] = zcon;
675 return zcon;
676 }
677
678
679
680 //=============================================================================
681 //------------------------------transform--------------------------------------
682 // Return a node which computes the same function as this node, but in a
683 // faster or cheaper fashion.
684 Node *PhaseGVN::transform( Node *n ) {
685 return transform_no_reclaim(n);
686 }
687
688 //------------------------------transform--------------------------------------
689 // Return a node which computes the same function as this node, but
690 // in a faster or cheaper fashion.
691 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
692 NOT_PRODUCT( set_transforms(); )
693
694 // Apply the Ideal call in a loop until it no longer applies
695 Node *k = n;
696 NOT_PRODUCT( uint loop_count = 0; )
697 while( 1 ) {
698 Node *i = k->Ideal(this, /*can_reshape=*/false);
699 if( !i ) break;
700 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
701 k = i;
702 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
703 }
704 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
705
706
707 // If brand new node, make space in type array.
708 ensure_type_or_null(k);
709
710 // Since I just called 'Value' to compute the set of run-time values
711 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
712 // cache Value. Later requests for the local phase->type of this Node can
713 // use the cached Value instead of suffering with 'bottom_type'.
714 const Type *t = k->Value(this); // Get runtime Value set
715 assert(t != NULL, "value sanity");
716 if (type_or_null(k) != t) {
717 #ifndef PRODUCT
718 // Do not count initial visit to node as a transformation
719 if (type_or_null(k) == NULL) {
720 inc_new_values();
721 set_progress();
722 }
723 #endif
724 set_type(k, t);
725 // If k is a TypeNode, capture any more-precise type permanently into Node
726 k->raise_bottom_type(t);
727 }
728
729 if( t->singleton() && !k->is_Con() ) {
730 NOT_PRODUCT( set_progress(); )
731 return makecon(t); // Turn into a constant
732 }
733
734 // Now check for Identities
735 Node *i = k->Identity(this); // Look for a nearby replacement
736 if( i != k ) { // Found? Return replacement!
737 NOT_PRODUCT( set_progress(); )
738 return i;
739 }
740
741 // Global Value Numbering
742 i = hash_find_insert(k); // Insert if new
743 if( i && (i != k) ) {
744 // Return the pre-existing node
745 NOT_PRODUCT( set_progress(); )
746 return i;
747 }
748
749 // Return Idealized original
750 return k;
751 }
752
753 #ifdef ASSERT
754 //------------------------------dead_loop_check--------------------------------
755 // Check for a simple dead loop when a data node references itself directly
756 // or through an other data node excluding cons and phis.
757 void PhaseGVN::dead_loop_check( Node *n ) {
758 // Phi may reference itself in a loop
759 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
760 // Do 2 levels check and only data inputs.
761 bool no_dead_loop = true;
762 uint cnt = n->req();
763 for (uint i = 1; i < cnt && no_dead_loop; i++) {
764 Node *in = n->in(i);
765 if (in == n) {
766 no_dead_loop = false;
767 } else if (in != NULL && !in->is_dead_loop_safe()) {
768 uint icnt = in->req();
769 for (uint j = 1; j < icnt && no_dead_loop; j++) {
770 if (in->in(j) == n || in->in(j) == in)
771 no_dead_loop = false;
772 }
773 }
774 }
775 if (!no_dead_loop) n->dump(3);
776 assert(no_dead_loop, "dead loop detected");
777 }
778 }
779 #endif
780
781 //=============================================================================
782 //------------------------------PhaseIterGVN-----------------------------------
783 // Initialize hash table to fresh and clean for +VerifyOpto
784 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ),
785 _stack(C->unique() >> 1),
786 _delay_transform(false) {
787 }
788
789 //------------------------------PhaseIterGVN-----------------------------------
790 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
791 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
792 _worklist( igvn->_worklist ),
793 _stack( igvn->_stack ),
794 _delay_transform(igvn->_delay_transform)
795 {
796 }
797
798 //------------------------------PhaseIterGVN-----------------------------------
799 // Initialize with previous PhaseGVN info from Parser
800 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
801 _worklist(*C->for_igvn()),
802 _stack(C->unique() >> 1),
803 _delay_transform(false)
804 {
805 uint max;
806
807 // Dead nodes in the hash table inherited from GVN were not treated as
808 // roots during def-use info creation; hence they represent an invisible
809 // use. Clear them out.
810 max = _table.size();
811 for( uint i = 0; i < max; ++i ) {
812 Node *n = _table.at(i);
813 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
814 if( n->is_top() ) continue;
815 assert( false, "Parse::remove_useless_nodes missed this node");
816 hash_delete(n);
817 }
818 }
819
820 // Any Phis or Regions on the worklist probably had uses that could not
821 // make more progress because the uses were made while the Phis and Regions
822 // were in half-built states. Put all uses of Phis and Regions on worklist.
823 max = _worklist.size();
824 for( uint j = 0; j < max; j++ ) {
825 Node *n = _worklist.at(j);
826 uint uop = n->Opcode();
827 if( uop == Op_Phi || uop == Op_Region ||
828 n->is_Type() ||
829 n->is_Mem() )
830 add_users_to_worklist(n);
831 }
832 }
833
834
835 #ifndef PRODUCT
836 void PhaseIterGVN::verify_step(Node* n) {
837 _verify_window[_verify_counter % _verify_window_size] = n;
838 ++_verify_counter;
839 ResourceMark rm;
840 ResourceArea *area = Thread::current()->resource_area();
841 VectorSet old_space(area), new_space(area);
842 if (C->unique() < 1000 ||
843 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
844 ++_verify_full_passes;
845 Node::verify_recur(C->root(), -1, old_space, new_space);
846 }
847 const int verify_depth = 4;
848 for ( int i = 0; i < _verify_window_size; i++ ) {
849 Node* n = _verify_window[i];
850 if ( n == NULL ) continue;
851 if( n->in(0) == NodeSentinel ) { // xform_idom
852 _verify_window[i] = n->in(1);
853 --i; continue;
854 }
855 // Typical fanout is 1-2, so this call visits about 6 nodes.
856 Node::verify_recur(n, verify_depth, old_space, new_space);
857 }
858 }
859 #endif
860
861
862 //------------------------------init_worklist----------------------------------
863 // Initialize worklist for each node.
864 void PhaseIterGVN::init_worklist( Node *n ) {
865 if( _worklist.member(n) ) return;
866 _worklist.push(n);
867 uint cnt = n->req();
868 for( uint i =0 ; i < cnt; i++ ) {
869 Node *m = n->in(i);
870 if( m ) init_worklist(m);
871 }
872 }
873
874 //------------------------------optimize---------------------------------------
875 void PhaseIterGVN::optimize() {
876 debug_only(uint num_processed = 0;);
877 #ifndef PRODUCT
878 {
879 _verify_counter = 0;
880 _verify_full_passes = 0;
881 for ( int i = 0; i < _verify_window_size; i++ ) {
882 _verify_window[i] = NULL;
883 }
884 }
885 #endif
886
887 #ifdef ASSERT
888 Node* prev = NULL;
889 uint rep_cnt = 0;
890 #endif
891 uint loop_count = 0;
892
893 // Pull from worklist; transform node;
894 // If node has changed: update edge info and put uses on worklist.
895 while( _worklist.size() ) {
896 if (C->check_node_count(NodeLimitFudgeFactor * 2,
897 "out of nodes optimizing method")) {
898 return;
899 }
900 Node *n = _worklist.pop();
901 if (++loop_count >= K * C->live_nodes()) {
902 debug_only(n->dump(4);)
903 assert(false, "infinite loop in PhaseIterGVN::optimize");
904 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
905 return;
906 }
907 #ifdef ASSERT
908 if (n == prev) {
909 if (++rep_cnt > 3) {
910 n->dump(4);
911 assert(false, "loop in Ideal transformation");
912 }
913 } else {
914 rep_cnt = 0;
915 }
916 prev = n;
917 #endif
918 if (TraceIterativeGVN && Verbose) {
919 tty->print(" Pop ");
920 NOT_PRODUCT( n->dump(); )
921 debug_only(if( (num_processed++ % 100) == 0 ) _worklist.print_set();)
922 }
923
924 if (n->outcnt() != 0) {
925
926 #ifndef PRODUCT
927 uint wlsize = _worklist.size();
928 const Type* oldtype = type_or_null(n);
929 #endif //PRODUCT
930
931 Node *nn = transform_old(n);
932
933 #ifndef PRODUCT
934 if (TraceIterativeGVN) {
935 const Type* newtype = type_or_null(n);
936 if (nn != n) {
937 // print old node
938 tty->print("< ");
939 if (oldtype != newtype && oldtype != NULL) {
940 oldtype->dump();
941 }
942 do { tty->print("\t"); } while (tty->position() < 16);
943 tty->print("<");
944 n->dump();
945 }
946 if (oldtype != newtype || nn != n) {
947 // print new node and/or new type
948 if (oldtype == NULL) {
949 tty->print("* ");
950 } else if (nn != n) {
951 tty->print("> ");
952 } else {
953 tty->print("= ");
954 }
955 if (newtype == NULL) {
956 tty->print("null");
957 } else {
958 newtype->dump();
959 }
960 do { tty->print("\t"); } while (tty->position() < 16);
961 nn->dump();
962 }
963 if (Verbose && wlsize < _worklist.size()) {
964 tty->print(" Push {");
965 while (wlsize != _worklist.size()) {
966 Node* pushed = _worklist.at(wlsize++);
967 tty->print(" %d", pushed->_idx);
968 }
969 tty->print_cr(" }");
970 }
971 }
972 if( VerifyIterativeGVN && nn != n ) {
973 verify_step((Node*) NULL); // ignore n, it might be subsumed
974 }
975 #endif
976 } else if (!n->is_top()) {
977 remove_dead_node(n);
978 }
979 }
980
981 #ifndef PRODUCT
982 C->verify_graph_edges();
983 if( VerifyOpto && allow_progress() ) {
984 // Must turn off allow_progress to enable assert and break recursion
985 C->root()->verify();
986 { // Check if any progress was missed using IterGVN
987 // Def-Use info enables transformations not attempted in wash-pass
988 // e.g. Region/Phi cleanup, ...
989 // Null-check elision -- may not have reached fixpoint
990 // do not propagate to dominated nodes
991 ResourceMark rm;
992 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
993 // Fill worklist completely
994 igvn2.init_worklist(C->root());
995
996 igvn2.set_allow_progress(false);
997 igvn2.optimize();
998 igvn2.set_allow_progress(true);
999 }
1000 }
1001 if ( VerifyIterativeGVN && PrintOpto ) {
1002 if ( _verify_counter == _verify_full_passes )
1003 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
1004 _verify_full_passes);
1005 else
1006 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
1007 _verify_counter, _verify_full_passes);
1008 }
1009 #endif
1010 }
1011
1012
1013 //------------------register_new_node_with_optimizer---------------------------
1014 // Register a new node with the optimizer. Update the types array, the def-use
1015 // info. Put on worklist.
1016 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1017 set_type_bottom(n);
1018 _worklist.push(n);
1019 if (orig != NULL) C->copy_node_notes_to(n, orig);
1020 return n;
1021 }
1022
1023 //------------------------------transform--------------------------------------
1024 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1025 Node *PhaseIterGVN::transform( Node *n ) {
1026 if (_delay_transform) {
1027 // Register the node but don't optimize for now
1028 register_new_node_with_optimizer(n);
1029 return n;
1030 }
1031
1032 // If brand new node, make space in type array, and give it a type.
1033 ensure_type_or_null(n);
1034 if (type_or_null(n) == NULL) {
1035 set_type_bottom(n);
1036 }
1037
1038 return transform_old(n);
1039 }
1040
1041 //------------------------------transform_old----------------------------------
1042 Node *PhaseIterGVN::transform_old( Node *n ) {
1043 #ifndef PRODUCT
1044 debug_only(uint loop_count = 0;);
1045 set_transforms();
1046 #endif
1047 // Remove 'n' from hash table in case it gets modified
1048 _table.hash_delete(n);
1049 if( VerifyIterativeGVN ) {
1050 assert( !_table.find_index(n->_idx), "found duplicate entry in table");
1051 }
1052
1053 // Apply the Ideal call in a loop until it no longer applies
1054 Node *k = n;
1055 DEBUG_ONLY(dead_loop_check(k);)
1056 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1057 Node *i = k->Ideal(this, /*can_reshape=*/true);
1058 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1059 #ifndef PRODUCT
1060 if( VerifyIterativeGVN )
1061 verify_step(k);
1062 if( i && VerifyOpto ) {
1063 if( !allow_progress() ) {
1064 if (i->is_Add() && i->outcnt() == 1) {
1065 // Switched input to left side because this is the only use
1066 } else if( i->is_If() && (i->in(0) == NULL) ) {
1067 // This IF is dead because it is dominated by an equivalent IF When
1068 // dominating if changed, info is not propagated sparsely to 'this'
1069 // Propagating this info further will spuriously identify other
1070 // progress.
1071 return i;
1072 } else
1073 set_progress();
1074 } else
1075 set_progress();
1076 }
1077 #endif
1078
1079 while( i ) {
1080 #ifndef PRODUCT
1081 debug_only( if( loop_count >= K ) i->dump(4); )
1082 assert(loop_count < K, "infinite loop in PhaseIterGVN::transform");
1083 debug_only( loop_count++; )
1084 #endif
1085 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1086 // Made a change; put users of original Node on worklist
1087 add_users_to_worklist( k );
1088 // Replacing root of transform tree?
1089 if( k != i ) {
1090 // Make users of old Node now use new.
1091 subsume_node( k, i );
1092 k = i;
1093 }
1094 DEBUG_ONLY(dead_loop_check(k);)
1095 // Try idealizing again
1096 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1097 i = k->Ideal(this, /*can_reshape=*/true);
1098 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1099 #ifndef PRODUCT
1100 if( VerifyIterativeGVN )
1101 verify_step(k);
1102 if( i && VerifyOpto ) set_progress();
1103 #endif
1104 }
1105
1106 // If brand new node, make space in type array.
1107 ensure_type_or_null(k);
1108
1109 // See what kind of values 'k' takes on at runtime
1110 const Type *t = k->Value(this);
1111 assert(t != NULL, "value sanity");
1112
1113 // Since I just called 'Value' to compute the set of run-time values
1114 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1115 // cache Value. Later requests for the local phase->type of this Node can
1116 // use the cached Value instead of suffering with 'bottom_type'.
1117 if (t != type_or_null(k)) {
1118 NOT_PRODUCT( set_progress(); )
1119 NOT_PRODUCT( inc_new_values();)
1120 set_type(k, t);
1121 // If k is a TypeNode, capture any more-precise type permanently into Node
1122 k->raise_bottom_type(t);
1123 // Move users of node to worklist
1124 add_users_to_worklist( k );
1125 }
1126
1127 // If 'k' computes a constant, replace it with a constant
1128 if( t->singleton() && !k->is_Con() ) {
1129 NOT_PRODUCT( set_progress(); )
1130 Node *con = makecon(t); // Make a constant
1131 add_users_to_worklist( k );
1132 subsume_node( k, con ); // Everybody using k now uses con
1133 return con;
1134 }
1135
1136 // Now check for Identities
1137 i = k->Identity(this); // Look for a nearby replacement
1138 if( i != k ) { // Found? Return replacement!
1139 NOT_PRODUCT( set_progress(); )
1140 add_users_to_worklist( k );
1141 subsume_node( k, i ); // Everybody using k now uses i
1142 return i;
1143 }
1144
1145 // Global Value Numbering
1146 i = hash_find_insert(k); // Check for pre-existing node
1147 if( i && (i != k) ) {
1148 // Return the pre-existing node if it isn't dead
1149 NOT_PRODUCT( set_progress(); )
1150 add_users_to_worklist( k );
1151 subsume_node( k, i ); // Everybody using k now uses i
1152 return i;
1153 }
1154
1155 // Return Idealized original
1156 return k;
1157 }
1158
1159 //---------------------------------saturate------------------------------------
1160 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1161 const Type* limit_type) const {
1162 return new_type->narrow(old_type);
1163 }
1164
1165 //------------------------------remove_globally_dead_node----------------------
1166 // Kill a globally dead Node. All uses are also globally dead and are
1167 // aggressively trimmed.
1168 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1169 enum DeleteProgress {
1170 PROCESS_INPUTS,
1171 PROCESS_OUTPUTS
1172 };
1173 assert(_stack.is_empty(), "not empty");
1174 _stack.push(dead, PROCESS_INPUTS);
1175
1176 while (_stack.is_nonempty()) {
1177 dead = _stack.node();
1178 uint progress_state = _stack.index();
1179 assert(dead != C->root(), "killing root, eh?");
1180 assert(!dead->is_top(), "add check for top when pushing");
1181 NOT_PRODUCT( set_progress(); )
1182 if (progress_state == PROCESS_INPUTS) {
1183 // After following inputs, continue to outputs
1184 _stack.set_index(PROCESS_OUTPUTS);
1185 if (!dead->is_Con()) { // Don't kill cons but uses
1186 bool recurse = false;
1187 // Remove from hash table
1188 _table.hash_delete( dead );
1189 // Smash all inputs to 'dead', isolating him completely
1190 for (uint i = 0; i < dead->req(); i++) {
1191 Node *in = dead->in(i);
1192 if (in != NULL && in != C->top()) { // Points to something?
1193 int nrep = dead->replace_edge(in, NULL); // Kill edges
1194 assert((nrep > 0), "sanity");
1195 if (in->outcnt() == 0) { // Made input go dead?
1196 _stack.push(in, PROCESS_INPUTS); // Recursively remove
1197 recurse = true;
1198 } else if (in->outcnt() == 1 &&
1199 in->has_special_unique_user()) {
1200 _worklist.push(in->unique_out());
1201 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1202 if (in->Opcode() == Op_Region) {
1203 _worklist.push(in);
1204 } else if (in->is_Store()) {
1205 DUIterator_Fast imax, i = in->fast_outs(imax);
1206 _worklist.push(in->fast_out(i));
1207 i++;
1208 if (in->outcnt() == 2) {
1209 _worklist.push(in->fast_out(i));
1210 i++;
1211 }
1212 assert(!(i < imax), "sanity");
1213 }
1214 }
1215 if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory &&
1216 in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) {
1217 // A Load that directly follows an InitializeNode is
1218 // going away. The Stores that follow are candidates
1219 // again to be captured by the InitializeNode.
1220 for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) {
1221 Node *n = in->fast_out(j);
1222 if (n->is_Store()) {
1223 _worklist.push(n);
1224 }
1225 }
1226 }
1227 } // if (in != NULL && in != C->top())
1228 } // for (uint i = 0; i < dead->req(); i++)
1229 if (recurse) {
1230 continue;
1231 }
1232 } // if (!dead->is_Con())
1233 } // if (progress_state == PROCESS_INPUTS)
1234
1235 // Aggressively kill globally dead uses
1236 // (Rather than pushing all the outs at once, we push one at a time,
1237 // plus the parent to resume later, because of the indefinite number
1238 // of edge deletions per loop trip.)
1239 if (dead->outcnt() > 0) {
1240 // Recursively remove output edges
1241 _stack.push(dead->raw_out(0), PROCESS_INPUTS);
1242 } else {
1243 // Finished disconnecting all input and output edges.
1244 _stack.pop();
1245 // Remove dead node from iterative worklist
1246 _worklist.remove(dead);
1247 // Constant node that has no out-edges and has only one in-edge from
1248 // root is usually dead. However, sometimes reshaping walk makes
1249 // it reachable by adding use edges. So, we will NOT count Con nodes
1250 // as dead to be conservative about the dead node count at any
1251 // given time.
1252 if (!dead->is_Con()) {
1253 C->record_dead_node(dead->_idx);
1254 }
1255 if (dead->is_macro()) {
1256 C->remove_macro_node(dead);
1257 }
1258 if (dead->is_expensive()) {
1259 C->remove_expensive_node(dead);
1260 }
1261 }
1262 } // while (_stack.is_nonempty())
1263 }
1264
1265 //------------------------------subsume_node-----------------------------------
1266 // Remove users from node 'old' and add them to node 'nn'.
1267 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1268 assert( old != hash_find(old), "should already been removed" );
1269 assert( old != C->top(), "cannot subsume top node");
1270 // Copy debug or profile information to the new version:
1271 C->copy_node_notes_to(nn, old);
1272 // Move users of node 'old' to node 'nn'
1273 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1274 Node* use = old->last_out(i); // for each use...
1275 // use might need re-hashing (but it won't if it's a new node)
1276 bool is_in_table = _table.hash_delete( use );
1277 // Update use-def info as well
1278 // We remove all occurrences of old within use->in,
1279 // so as to avoid rehashing any node more than once.
1280 // The hash table probe swamps any outer loop overhead.
1281 uint num_edges = 0;
1282 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1283 if (use->in(j) == old) {
1284 use->set_req(j, nn);
1285 ++num_edges;
1286 }
1287 }
1288 // Insert into GVN hash table if unique
1289 // If a duplicate, 'use' will be cleaned up when pulled off worklist
1290 if( is_in_table ) {
1291 hash_find_insert(use);
1292 }
1293 i -= num_edges; // we deleted 1 or more copies of this edge
1294 }
1295
1296 // Smash all inputs to 'old', isolating him completely
1297 Node *temp = new (C) Node(1);
1298 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1299 remove_dead_node( old );
1300 temp->del_req(0); // Yank bogus edge
1301 #ifndef PRODUCT
1302 if( VerifyIterativeGVN ) {
1303 for ( int i = 0; i < _verify_window_size; i++ ) {
1304 if ( _verify_window[i] == old )
1305 _verify_window[i] = nn;
1306 }
1307 }
1308 #endif
1309 _worklist.remove(temp); // this can be necessary
1310 temp->destruct(); // reuse the _idx of this little guy
1311 }
1312
1313 //------------------------------add_users_to_worklist--------------------------
1314 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1315 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1316 _worklist.push(n->fast_out(i)); // Push on worklist
1317 }
1318 }
1319
1320 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1321 add_users_to_worklist0(n);
1322
1323 // Move users of node to worklist
1324 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1325 Node* use = n->fast_out(i); // Get use
1326
1327 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1328 use->is_Store() ) // Enable store/load same address
1329 add_users_to_worklist0(use);
1330
1331 // If we changed the receiver type to a call, we need to revisit
1332 // the Catch following the call. It's looking for a non-NULL
1333 // receiver to know when to enable the regular fall-through path
1334 // in addition to the NullPtrException path.
1335 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1336 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
1337 if (p != NULL) {
1338 add_users_to_worklist0(p);
1339 }
1340 }
1341
1342 if( use->is_Cmp() ) { // Enable CMP/BOOL optimization
1343 add_users_to_worklist(use); // Put Bool on worklist
1344 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1345 // phi merging either 0 or 1 onto the worklist
1346 if (use->outcnt() > 0) {
1347 Node* bol = use->raw_out(0);
1348 if (bol->outcnt() > 0) {
1349 Node* iff = bol->raw_out(0);
1350 if (iff->outcnt() == 2) {
1351 Node* ifproj0 = iff->raw_out(0);
1352 Node* ifproj1 = iff->raw_out(1);
1353 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1354 Node* region0 = ifproj0->raw_out(0);
1355 Node* region1 = ifproj1->raw_out(0);
1356 if( region0 == region1 )
1357 add_users_to_worklist0(region0);
1358 }
1359 }
1360 }
1361 }
1362 }
1363
1364 uint use_op = use->Opcode();
1365 // If changed Cast input, check Phi users for simple cycles
1366 if( use->is_ConstraintCast() || use->is_CheckCastPP() ) {
1367 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1368 Node* u = use->fast_out(i2);
1369 if (u->is_Phi())
1370 _worklist.push(u);
1371 }
1372 }
1373 // If changed LShift inputs, check RShift users for useless sign-ext
1374 if( use_op == Op_LShiftI ) {
1375 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1376 Node* u = use->fast_out(i2);
1377 if (u->Opcode() == Op_RShiftI)
1378 _worklist.push(u);
1379 }
1380 }
1381 // If changed AddP inputs, check Stores for loop invariant
1382 if( use_op == Op_AddP ) {
1383 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1384 Node* u = use->fast_out(i2);
1385 if (u->is_Mem())
1386 _worklist.push(u);
1387 }
1388 }
1389 // If changed initialization activity, check dependent Stores
1390 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1391 InitializeNode* init = use->as_Allocate()->initialization();
1392 if (init != NULL) {
1393 Node* imem = init->proj_out(TypeFunc::Memory);
1394 if (imem != NULL) add_users_to_worklist0(imem);
1395 }
1396 }
1397 if (use_op == Op_Initialize) {
1398 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
1399 if (imem != NULL) add_users_to_worklist0(imem);
1400 }
1401 }
1402 }
1403
1404 /**
1405 * Remove the speculative part of all types that we know of
1406 */
1407 void PhaseIterGVN::remove_speculative_types() {
1408 assert(UseTypeSpeculation, "speculation is off");
1409 for (uint i = 0; i < _types.Size(); i++) {
1410 const Type* t = _types.fast_lookup(i);
1411 if (t != NULL) {
1412 _types.map(i, t->remove_speculative());
1413 }
1414 }
1415 _table.check_no_speculative_types();
1416 }
1417
1418 //=============================================================================
1419 #ifndef PRODUCT
1420 uint PhaseCCP::_total_invokes = 0;
1421 uint PhaseCCP::_total_constants = 0;
1422 #endif
1423 //------------------------------PhaseCCP---------------------------------------
1424 // Conditional Constant Propagation, ala Wegman & Zadeck
1425 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1426 NOT_PRODUCT( clear_constants(); )
1427 assert( _worklist.size() == 0, "" );
1428 // Clear out _nodes from IterGVN. Must be clear to transform call.
1429 _nodes.clear(); // Clear out from IterGVN
1430 analyze();
1431 }
1432
1433 #ifndef PRODUCT
1434 //------------------------------~PhaseCCP--------------------------------------
1435 PhaseCCP::~PhaseCCP() {
1436 inc_invokes();
1437 _total_constants += count_constants();
1438 }
1439 #endif
1440
1441
1442 #ifdef ASSERT
1443 static bool ccp_type_widens(const Type* t, const Type* t0) {
1444 assert(t->meet(t0) == t, "Not monotonic");
1445 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1446 case Type::Int:
1447 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1448 break;
1449 case Type::Long:
1450 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1451 break;
1452 }
1453 return true;
1454 }
1455 #endif //ASSERT
1456
1457 //------------------------------analyze----------------------------------------
1458 void PhaseCCP::analyze() {
1459 // Initialize all types to TOP, optimistic analysis
1460 for (int i = C->unique() - 1; i >= 0; i--) {
1461 _types.map(i,Type::TOP);
1462 }
1463
1464 // Push root onto worklist
1465 Unique_Node_List worklist;
1466 worklist.push(C->root());
1467
1468 // Pull from worklist; compute new value; push changes out.
1469 // This loop is the meat of CCP.
1470 while( worklist.size() ) {
1471 Node *n = worklist.pop();
1472 const Type *t = n->Value(this);
1473 if (t != type(n)) {
1474 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1475 #ifndef PRODUCT
1476 if( TracePhaseCCP ) {
1477 t->dump();
1478 do { tty->print("\t"); } while (tty->position() < 16);
1479 n->dump();
1480 }
1481 #endif
1482 set_type(n, t);
1483 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1484 Node* m = n->fast_out(i); // Get user
1485 if( m->is_Region() ) { // New path to Region? Must recheck Phis too
1486 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1487 Node* p = m->fast_out(i2); // Propagate changes to uses
1488 if( p->bottom_type() != type(p) ) // If not already bottomed out
1489 worklist.push(p); // Propagate change to user
1490 }
1491 }
1492 // If we changed the receiver type to a call, we need to revisit
1493 // the Catch following the call. It's looking for a non-NULL
1494 // receiver to know when to enable the regular fall-through path
1495 // in addition to the NullPtrException path
1496 if (m->is_Call()) {
1497 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1498 Node* p = m->fast_out(i2); // Propagate changes to uses
1499 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1)
1500 worklist.push(p->unique_out());
1501 }
1502 }
1503 if( m->bottom_type() != type(m) ) // If not already bottomed out
1504 worklist.push(m); // Propagate change to user
1505 }
1506 }
1507 }
1508 }
1509
1510 //------------------------------do_transform-----------------------------------
1511 // Top level driver for the recursive transformer
1512 void PhaseCCP::do_transform() {
1513 // Correct leaves of new-space Nodes; they point to old-space.
1514 C->set_root( transform(C->root())->as_Root() );
1515 assert( C->top(), "missing TOP node" );
1516 assert( C->root(), "missing root" );
1517 }
1518
1519 //------------------------------transform--------------------------------------
1520 // Given a Node in old-space, clone him into new-space.
1521 // Convert any of his old-space children into new-space children.
1522 Node *PhaseCCP::transform( Node *n ) {
1523 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1524 if( new_node != NULL )
1525 return new_node; // Been there, done that, return old answer
1526 new_node = transform_once(n); // Check for constant
1527 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1528
1529 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1530 GrowableArray <Node *> trstack(C->unique() >> 1);
1531
1532 trstack.push(new_node); // Process children of cloned node
1533 while ( trstack.is_nonempty() ) {
1534 Node *clone = trstack.pop();
1535 uint cnt = clone->req();
1536 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1537 Node *input = clone->in(i);
1538 if( input != NULL ) { // Ignore NULLs
1539 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1540 if( new_input == NULL ) {
1541 new_input = transform_once(input); // Check for constant
1542 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1543 trstack.push(new_input);
1544 }
1545 assert( new_input == clone->in(i), "insanity check");
1546 }
1547 }
1548 }
1549 return new_node;
1550 }
1551
1552
1553 //------------------------------transform_once---------------------------------
1554 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1555 Node *PhaseCCP::transform_once( Node *n ) {
1556 const Type *t = type(n);
1557 // Constant? Use constant Node instead
1558 if( t->singleton() ) {
1559 Node *nn = n; // Default is to return the original constant
1560 if( t == Type::TOP ) {
1561 // cache my top node on the Compile instance
1562 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1563 C->set_cached_top_node( ConNode::make(C, Type::TOP) );
1564 set_type(C->top(), Type::TOP);
1565 }
1566 nn = C->top();
1567 }
1568 if( !n->is_Con() ) {
1569 if( t != Type::TOP ) {
1570 nn = makecon(t); // ConNode::make(t);
1571 NOT_PRODUCT( inc_constants(); )
1572 } else if( n->is_Region() ) { // Unreachable region
1573 // Note: nn == C->top()
1574 n->set_req(0, NULL); // Cut selfreference
1575 // Eagerly remove dead phis to avoid phis copies creation.
1576 for (DUIterator i = n->outs(); n->has_out(i); i++) {
1577 Node* m = n->out(i);
1578 if( m->is_Phi() ) {
1579 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1580 replace_node(m, nn);
1581 --i; // deleted this phi; rescan starting with next position
1582 }
1583 }
1584 }
1585 replace_node(n,nn); // Update DefUse edges for new constant
1586 }
1587 return nn;
1588 }
1589
1590 // If x is a TypeNode, capture any more-precise type permanently into Node
1591 if (t != n->bottom_type()) {
1592 hash_delete(n); // changing bottom type may force a rehash
1593 n->raise_bottom_type(t);
1594 _worklist.push(n); // n re-enters the hash table via the worklist
1595 }
1596
1597 // Idealize graph using DU info. Must clone() into new-space.
1598 // DU info is generally used to show profitability, progress or safety
1599 // (but generally not needed for correctness).
1600 Node *nn = n->Ideal_DU_postCCP(this);
1601
1602 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1603 switch( n->Opcode() ) {
1604 case Op_FastLock: // Revisit FastLocks for lock coarsening
1605 case Op_If:
1606 case Op_CountedLoopEnd:
1607 case Op_Region:
1608 case Op_Loop:
1609 case Op_CountedLoop:
1610 case Op_Conv2B:
1611 case Op_Opaque1:
1612 case Op_Opaque2:
1613 _worklist.push(n);
1614 break;
1615 default:
1616 break;
1617 }
1618 if( nn ) {
1619 _worklist.push(n);
1620 // Put users of 'n' onto worklist for second igvn transform
1621 add_users_to_worklist(n);
1622 return nn;
1623 }
1624
1625 return n;
1626 }
1627
1628 //---------------------------------saturate------------------------------------
1629 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1630 const Type* limit_type) const {
1631 const Type* wide_type = new_type->widen(old_type, limit_type);
1632 if (wide_type != new_type) { // did we widen?
1633 // If so, we may have widened beyond the limit type. Clip it back down.
1634 new_type = wide_type->filter(limit_type);
1635 }
1636 return new_type;
1637 }
1638
1639 //------------------------------print_statistics-------------------------------
1640 #ifndef PRODUCT
1641 void PhaseCCP::print_statistics() {
1642 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1643 }
1644 #endif
1645
1646
1647 //=============================================================================
1648 #ifndef PRODUCT
1649 uint PhasePeephole::_total_peepholes = 0;
1650 #endif
1651 //------------------------------PhasePeephole----------------------------------
1652 // Conditional Constant Propagation, ala Wegman & Zadeck
1653 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1654 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1655 NOT_PRODUCT( clear_peepholes(); )
1656 }
1657
1658 #ifndef PRODUCT
1659 //------------------------------~PhasePeephole---------------------------------
1660 PhasePeephole::~PhasePeephole() {
1661 _total_peepholes += count_peepholes();
1662 }
1663 #endif
1664
1665 //------------------------------transform--------------------------------------
1666 Node *PhasePeephole::transform( Node *n ) {
1667 ShouldNotCallThis();
1668 return NULL;
1669 }
1670
1671 //------------------------------do_transform-----------------------------------
1672 void PhasePeephole::do_transform() {
1673 bool method_name_not_printed = true;
1674
1675 // Examine each basic block
1676 for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) {
1677 Block* block = _cfg.get_block(block_number);
1678 bool block_not_printed = true;
1679
1680 // and each instruction within a block
1681 uint end_index = block->number_of_nodes();
1682 // block->end_idx() not valid after PhaseRegAlloc
1683 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
1684 Node *n = block->get_node(instruction_index);
1685 if( n->is_Mach() ) {
1686 MachNode *m = n->as_Mach();
1687 int deleted_count = 0;
1688 // check for peephole opportunities
1689 MachNode *m2 = m->peephole( block, instruction_index, _regalloc, deleted_count, C );
1690 if( m2 != NULL ) {
1691 #ifndef PRODUCT
1692 if( PrintOptoPeephole ) {
1693 // Print method, first time only
1694 if( C->method() && method_name_not_printed ) {
1695 C->method()->print_short_name(); tty->cr();
1696 method_name_not_printed = false;
1697 }
1698 // Print this block
1699 if( Verbose && block_not_printed) {
1700 tty->print_cr("in block");
1701 block->dump();
1702 block_not_printed = false;
1703 }
1704 // Print instructions being deleted
1705 for( int i = (deleted_count - 1); i >= 0; --i ) {
1706 block->get_node(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
1707 }
1708 tty->print_cr("replaced with");
1709 // Print new instruction
1710 m2->format(_regalloc);
1711 tty->print("\n\n");
1712 }
1713 #endif
1714 // Remove old nodes from basic block and update instruction_index
1715 // (old nodes still exist and may have edges pointing to them
1716 // as register allocation info is stored in the allocator using
1717 // the node index to live range mappings.)
1718 uint safe_instruction_index = (instruction_index - deleted_count);
1719 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
1720 block->remove_node( instruction_index );
1721 }
1722 // install new node after safe_instruction_index
1723 block->insert_node(m2, safe_instruction_index + 1);
1724 end_index = block->number_of_nodes() - 1; // Recompute new block size
1725 NOT_PRODUCT( inc_peepholes(); )
1726 }
1727 }
1728 }
1729 }
1730 }
1731
1732 //------------------------------print_statistics-------------------------------
1733 #ifndef PRODUCT
1734 void PhasePeephole::print_statistics() {
1735 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
1736 }
1737 #endif
1738
1739
1740 //=============================================================================
1741 //------------------------------set_req_X--------------------------------------
1742 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
1743 assert( is_not_dead(n), "can not use dead node");
1744 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
1745 Node *old = in(i);
1746 set_req(i, n);
1747
1748 // old goes dead?
1749 if( old ) {
1750 switch (old->outcnt()) {
1751 case 0:
1752 // Put into the worklist to kill later. We do not kill it now because the
1753 // recursive kill will delete the current node (this) if dead-loop exists
1754 if (!old->is_top())
1755 igvn->_worklist.push( old );
1756 break;
1757 case 1:
1758 if( old->is_Store() || old->has_special_unique_user() )
1759 igvn->add_users_to_worklist( old );
1760 break;
1761 case 2:
1762 if( old->is_Store() )
1763 igvn->add_users_to_worklist( old );
1764 if( old->Opcode() == Op_Region )
1765 igvn->_worklist.push(old);
1766 break;
1767 case 3:
1768 if( old->Opcode() == Op_Region ) {
1769 igvn->_worklist.push(old);
1770 igvn->add_users_to_worklist( old );
1771 }
1772 break;
1773 default:
1774 break;
1775 }
1776 }
1777
1778 }
1779
1780 //-------------------------------replace_by-----------------------------------
1781 // Using def-use info, replace one node for another. Follow the def-use info
1782 // to all users of the OLD node. Then make all uses point to the NEW node.
1783 void Node::replace_by(Node *new_node) {
1784 assert(!is_top(), "top node has no DU info");
1785 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
1786 Node* use = last_out(i);
1787 uint uses_found = 0;
1788 for (uint j = 0; j < use->len(); j++) {
1789 if (use->in(j) == this) {
1790 if (j < use->req())
1791 use->set_req(j, new_node);
1792 else use->set_prec(j, new_node);
1793 uses_found++;
1794 }
1795 }
1796 i -= uses_found; // we deleted 1 or more copies of this edge
1797 }
1798 }
1799
1800 //=============================================================================
1801 //-----------------------------------------------------------------------------
1802 void Type_Array::grow( uint i ) {
1803 if( !_max ) {
1804 _max = 1;
1805 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
1806 _types[0] = NULL;
1807 }
1808 uint old = _max;
1809 while( i >= _max ) _max <<= 1; // Double to fit
1810 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
1811 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
1812 }
1813
1814 //------------------------------dump-------------------------------------------
1815 #ifndef PRODUCT
1816 void Type_Array::dump() const {
1817 uint max = Size();
1818 for( uint i = 0; i < max; i++ ) {
1819 if( _types[i] != NULL ) {
1820 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
1821 }
1822 }
1823 }
1824 #endif