1 /*
2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "opto/block.hpp"
28 #include "opto/callnode.hpp"
29 #include "opto/cfgnode.hpp"
30 #include "opto/connode.hpp"
31 #include "opto/idealGraphPrinter.hpp"
32 #include "opto/loopnode.hpp"
33 #include "opto/machnode.hpp"
34 #include "opto/opcodes.hpp"
35 #include "opto/phaseX.hpp"
36 #include "opto/regalloc.hpp"
37 #include "opto/rootnode.hpp"
38
39 //=============================================================================
40 #define NODE_HASH_MINIMUM_SIZE 255
41 //------------------------------NodeHash---------------------------------------
42 NodeHash::NodeHash(uint est_max_size) :
43 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
44 _a(Thread::current()->resource_area()),
45 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ),
46 _inserts(0), _insert_limit( insert_limit() ),
47 _look_probes(0), _lookup_hits(0), _lookup_misses(0),
48 _total_insert_probes(0), _total_inserts(0),
49 _insert_probes(0), _grows(0) {
50 // _sentinel must be in the current node space
51 _sentinel = new (Compile::current(), 1) ProjNode(NULL, TypeFunc::Control);
52 memset(_table,0,sizeof(Node*)*_max);
53 }
54
55 //------------------------------NodeHash---------------------------------------
56 NodeHash::NodeHash(Arena *arena, uint est_max_size) :
57 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
58 _a(arena),
59 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ),
60 _inserts(0), _insert_limit( insert_limit() ),
61 _look_probes(0), _lookup_hits(0), _lookup_misses(0),
62 _delete_probes(0), _delete_hits(0), _delete_misses(0),
63 _total_insert_probes(0), _total_inserts(0),
64 _insert_probes(0), _grows(0) {
65 // _sentinel must be in the current node space
66 _sentinel = new (Compile::current(), 1) ProjNode(NULL, TypeFunc::Control);
67 memset(_table,0,sizeof(Node*)*_max);
68 }
69
70 //------------------------------NodeHash---------------------------------------
71 NodeHash::NodeHash(NodeHash *nh) {
72 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
73 // just copy in all the fields
74 *this = *nh;
75 // nh->_sentinel must be in the current node space
76 }
77
78 //------------------------------hash_find--------------------------------------
79 // Find in hash table
80 Node *NodeHash::hash_find( const Node *n ) {
81 // ((Node*)n)->set_hash( n->hash() );
82 uint hash = n->hash();
83 if (hash == Node::NO_HASH) {
84 debug_only( _lookup_misses++ );
85 return NULL;
86 }
87 uint key = hash & (_max-1);
88 uint stride = key | 0x01;
89 debug_only( _look_probes++ );
90 Node *k = _table[key]; // Get hashed value
91 if( !k ) { // ?Miss?
92 debug_only( _lookup_misses++ );
93 return NULL; // Miss!
94 }
95
96 int op = n->Opcode();
97 uint req = n->req();
98 while( 1 ) { // While probing hash table
99 if( k->req() == req && // Same count of inputs
100 k->Opcode() == op ) { // Same Opcode
101 for( uint i=0; i<req; i++ )
102 if( n->in(i)!=k->in(i)) // Different inputs?
103 goto collision; // "goto" is a speed hack...
104 if( n->cmp(*k) ) { // Check for any special bits
105 debug_only( _lookup_hits++ );
106 return k; // Hit!
107 }
108 }
109 collision:
110 debug_only( _look_probes++ );
111 key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime
112 k = _table[key]; // Get hashed value
113 if( !k ) { // ?Miss?
114 debug_only( _lookup_misses++ );
115 return NULL; // Miss!
116 }
117 }
118 ShouldNotReachHere();
119 return NULL;
120 }
121
122 //------------------------------hash_find_insert-------------------------------
123 // Find in hash table, insert if not already present
124 // Used to preserve unique entries in hash table
125 Node *NodeHash::hash_find_insert( Node *n ) {
126 // n->set_hash( );
127 uint hash = n->hash();
128 if (hash == Node::NO_HASH) {
129 debug_only( _lookup_misses++ );
130 return NULL;
131 }
132 uint key = hash & (_max-1);
133 uint stride = key | 0x01; // stride must be relatively prime to table siz
134 uint first_sentinel = 0; // replace a sentinel if seen.
135 debug_only( _look_probes++ );
136 Node *k = _table[key]; // Get hashed value
137 if( !k ) { // ?Miss?
138 debug_only( _lookup_misses++ );
139 _table[key] = n; // Insert into table!
140 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
141 check_grow(); // Grow table if insert hit limit
142 return NULL; // Miss!
143 }
144 else if( k == _sentinel ) {
145 first_sentinel = key; // Can insert here
146 }
147
148 int op = n->Opcode();
149 uint req = n->req();
150 while( 1 ) { // While probing hash table
151 if( k->req() == req && // Same count of inputs
152 k->Opcode() == op ) { // Same Opcode
153 for( uint i=0; i<req; i++ )
154 if( n->in(i)!=k->in(i)) // Different inputs?
155 goto collision; // "goto" is a speed hack...
156 if( n->cmp(*k) ) { // Check for any special bits
157 debug_only( _lookup_hits++ );
158 return k; // Hit!
159 }
160 }
161 collision:
162 debug_only( _look_probes++ );
163 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
164 k = _table[key]; // Get hashed value
165 if( !k ) { // ?Miss?
166 debug_only( _lookup_misses++ );
167 key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel?
168 _table[key] = n; // Insert into table!
169 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
170 check_grow(); // Grow table if insert hit limit
171 return NULL; // Miss!
172 }
173 else if( first_sentinel == 0 && k == _sentinel ) {
174 first_sentinel = key; // Can insert here
175 }
176
177 }
178 ShouldNotReachHere();
179 return NULL;
180 }
181
182 //------------------------------hash_insert------------------------------------
183 // Insert into hash table
184 void NodeHash::hash_insert( Node *n ) {
185 // // "conflict" comments -- print nodes that conflict
186 // bool conflict = false;
187 // n->set_hash();
188 uint hash = n->hash();
189 if (hash == Node::NO_HASH) {
190 return;
191 }
192 check_grow();
193 uint key = hash & (_max-1);
194 uint stride = key | 0x01;
195
196 while( 1 ) { // While probing hash table
197 debug_only( _insert_probes++ );
198 Node *k = _table[key]; // Get hashed value
199 if( !k || (k == _sentinel) ) break; // Found a slot
200 assert( k != n, "already inserted" );
201 // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; }
202 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
203 }
204 _table[key] = n; // Insert into table!
205 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
206 // if( conflict ) { n->dump(); }
207 }
208
209 //------------------------------hash_delete------------------------------------
210 // Replace in hash table with sentinel
211 bool NodeHash::hash_delete( const Node *n ) {
212 Node *k;
213 uint hash = n->hash();
214 if (hash == Node::NO_HASH) {
215 debug_only( _delete_misses++ );
216 return false;
217 }
218 uint key = hash & (_max-1);
219 uint stride = key | 0x01;
220 debug_only( uint counter = 0; );
221 for( ; /* (k != NULL) && (k != _sentinel) */; ) {
222 debug_only( counter++ );
223 debug_only( _delete_probes++ );
224 k = _table[key]; // Get hashed value
225 if( !k ) { // Miss?
226 debug_only( _delete_misses++ );
227 #ifdef ASSERT
228 if( VerifyOpto ) {
229 for( uint i=0; i < _max; i++ )
230 assert( _table[i] != n, "changed edges with rehashing" );
231 }
232 #endif
233 return false; // Miss! Not in chain
234 }
235 else if( n == k ) {
236 debug_only( _delete_hits++ );
237 _table[key] = _sentinel; // Hit! Label as deleted entry
238 debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table.
239 return true;
240 }
241 else {
242 // collision: move through table with prime offset
243 key = (key + stride/*7*/) & (_max-1);
244 assert( counter <= _insert_limit, "Cycle in hash-table");
245 }
246 }
247 ShouldNotReachHere();
248 return false;
249 }
250
251 //------------------------------round_up---------------------------------------
252 // Round up to nearest power of 2
253 uint NodeHash::round_up( uint x ) {
254 x += (x>>2); // Add 25% slop
255 if( x <16 ) return 16; // Small stuff
256 uint i=16;
257 while( i < x ) i <<= 1; // Double to fit
258 return i; // Return hash table size
259 }
260
261 //------------------------------grow-------------------------------------------
262 // Grow _table to next power of 2 and insert old entries
263 void NodeHash::grow() {
264 // Record old state
265 uint old_max = _max;
266 Node **old_table = _table;
267 // Construct new table with twice the space
268 _grows++;
269 _total_inserts += _inserts;
270 _total_insert_probes += _insert_probes;
271 _inserts = 0;
272 _insert_probes = 0;
273 _max = _max << 1;
274 _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) );
275 memset(_table,0,sizeof(Node*)*_max);
276 _insert_limit = insert_limit();
277 // Insert old entries into the new table
278 for( uint i = 0; i < old_max; i++ ) {
279 Node *m = *old_table++;
280 if( !m || m == _sentinel ) continue;
281 debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table.
282 hash_insert(m);
283 }
284 }
285
286 //------------------------------clear------------------------------------------
287 // Clear all entries in _table to NULL but keep storage
288 void NodeHash::clear() {
289 #ifdef ASSERT
290 // Unlock all nodes upon removal from table.
291 for (uint i = 0; i < _max; i++) {
292 Node* n = _table[i];
293 if (!n || n == _sentinel) continue;
294 n->exit_hash_lock();
295 }
296 #endif
297
298 memset( _table, 0, _max * sizeof(Node*) );
299 }
300
301 //-----------------------remove_useless_nodes----------------------------------
302 // Remove useless nodes from value table,
303 // implementation does not depend on hash function
304 void NodeHash::remove_useless_nodes(VectorSet &useful) {
305
306 // Dead nodes in the hash table inherited from GVN should not replace
307 // existing nodes, remove dead nodes.
308 uint max = size();
309 Node *sentinel_node = sentinel();
310 for( uint i = 0; i < max; ++i ) {
311 Node *n = at(i);
312 if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) {
313 debug_only(n->exit_hash_lock()); // Unlock the node when removed
314 _table[i] = sentinel_node; // Replace with placeholder
315 }
316 }
317 }
318
319 #ifndef PRODUCT
320 //------------------------------dump-------------------------------------------
321 // Dump statistics for the hash table
322 void NodeHash::dump() {
323 _total_inserts += _inserts;
324 _total_insert_probes += _insert_probes;
325 if( PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0) ) { // PrintOptoGVN
326 if( PrintCompilation2 ) {
327 for( uint i=0; i<_max; i++ )
328 if( _table[i] )
329 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
330 }
331 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max);
332 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
333 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
334 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
335 // sentinels increase lookup cost, but not insert cost
336 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
337 assert( _inserts+(_inserts>>3) < _max, "table too full" );
338 assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
339 }
340 }
341
342 Node *NodeHash::find_index(uint idx) { // For debugging
343 // Find an entry by its index value
344 for( uint i = 0; i < _max; i++ ) {
345 Node *m = _table[i];
346 if( !m || m == _sentinel ) continue;
347 if( m->_idx == (uint)idx ) return m;
348 }
349 return NULL;
350 }
351 #endif
352
353 #ifdef ASSERT
354 NodeHash::~NodeHash() {
355 // Unlock all nodes upon destruction of table.
356 if (_table != (Node**)badAddress) clear();
357 }
358
359 void NodeHash::operator=(const NodeHash& nh) {
360 // Unlock all nodes upon replacement of table.
361 if (&nh == this) return;
362 if (_table != (Node**)badAddress) clear();
363 memcpy(this, &nh, sizeof(*this));
364 // Do not increment hash_lock counts again.
365 // Instead, be sure we never again use the source table.
366 ((NodeHash*)&nh)->_table = (Node**)badAddress;
367 }
368
369
370 #endif
371
372
373 //=============================================================================
374 //------------------------------PhaseRemoveUseless-----------------------------
375 // 1) Use a breadthfirst walk to collect useful nodes reachable from root.
376 PhaseRemoveUseless::PhaseRemoveUseless( PhaseGVN *gvn, Unique_Node_List *worklist ) : Phase(Remove_Useless),
377 _useful(Thread::current()->resource_area()) {
378
379 // Implementation requires 'UseLoopSafepoints == true' and an edge from root
380 // to each SafePointNode at a backward branch. Inserted in add_safepoint().
381 if( !UseLoopSafepoints || !OptoRemoveUseless ) return;
382
383 // Identify nodes that are reachable from below, useful.
384 C->identify_useful_nodes(_useful);
385
386 // Remove all useless nodes from PhaseValues' recorded types
387 // Must be done before disconnecting nodes to preserve hash-table-invariant
388 gvn->remove_useless_nodes(_useful.member_set());
389
390 // Remove all useless nodes from future worklist
391 worklist->remove_useless_nodes(_useful.member_set());
392
393 // Disconnect 'useless' nodes that are adjacent to useful nodes
394 C->remove_useless_nodes(_useful);
395
396 // Remove edges from "root" to each SafePoint at a backward branch.
397 // They were inserted during parsing (see add_safepoint()) to make infinite
398 // loops without calls or exceptions visible to root, i.e., useful.
399 Node *root = C->root();
400 if( root != NULL ) {
401 for( uint i = root->req(); i < root->len(); ++i ) {
402 Node *n = root->in(i);
403 if( n != NULL && n->is_SafePoint() ) {
404 root->rm_prec(i);
405 --i;
406 }
407 }
408 }
409 }
410
411
412 //=============================================================================
413 //------------------------------PhaseTransform---------------------------------
414 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
415 _arena(Thread::current()->resource_area()),
416 _nodes(_arena),
417 _types(_arena)
418 {
419 init_con_caches();
420 #ifndef PRODUCT
421 clear_progress();
422 clear_transforms();
423 set_allow_progress(true);
424 #endif
425 // Force allocation for currently existing nodes
426 _types.map(C->unique(), NULL);
427 }
428
429 //------------------------------PhaseTransform---------------------------------
430 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
431 _arena(arena),
432 _nodes(arena),
433 _types(arena)
434 {
435 init_con_caches();
436 #ifndef PRODUCT
437 clear_progress();
438 clear_transforms();
439 set_allow_progress(true);
440 #endif
441 // Force allocation for currently existing nodes
442 _types.map(C->unique(), NULL);
443 }
444
445 //------------------------------PhaseTransform---------------------------------
446 // Initialize with previously generated type information
447 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
448 _arena(pt->_arena),
449 _nodes(pt->_nodes),
450 _types(pt->_types)
451 {
452 init_con_caches();
453 #ifndef PRODUCT
454 clear_progress();
455 clear_transforms();
456 set_allow_progress(true);
457 #endif
458 }
459
460 void PhaseTransform::init_con_caches() {
461 memset(_icons,0,sizeof(_icons));
462 memset(_lcons,0,sizeof(_lcons));
463 memset(_zcons,0,sizeof(_zcons));
464 }
465
466
467 //--------------------------------find_int_type--------------------------------
468 const TypeInt* PhaseTransform::find_int_type(Node* n) {
469 if (n == NULL) return NULL;
470 // Call type_or_null(n) to determine node's type since we might be in
471 // parse phase and call n->Value() may return wrong type.
472 // (For example, a phi node at the beginning of loop parsing is not ready.)
473 const Type* t = type_or_null(n);
474 if (t == NULL) return NULL;
475 return t->isa_int();
476 }
477
478
479 //-------------------------------find_long_type--------------------------------
480 const TypeLong* PhaseTransform::find_long_type(Node* n) {
481 if (n == NULL) return NULL;
482 // (See comment above on type_or_null.)
483 const Type* t = type_or_null(n);
484 if (t == NULL) return NULL;
485 return t->isa_long();
486 }
487
488
489 #ifndef PRODUCT
490 void PhaseTransform::dump_old2new_map() const {
491 _nodes.dump();
492 }
493
494 void PhaseTransform::dump_new( uint nidx ) const {
495 for( uint i=0; i<_nodes.Size(); i++ )
496 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
497 _nodes[i]->dump();
498 tty->cr();
499 tty->print_cr("Old index= %d",i);
500 return;
501 }
502 tty->print_cr("Node %d not found in the new indices", nidx);
503 }
504
505 //------------------------------dump_types-------------------------------------
506 void PhaseTransform::dump_types( ) const {
507 _types.dump();
508 }
509
510 //------------------------------dump_nodes_and_types---------------------------
511 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
512 VectorSet visited(Thread::current()->resource_area());
513 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
514 }
515
516 //------------------------------dump_nodes_and_types_recur---------------------
517 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
518 if( !n ) return;
519 if( depth == 0 ) return;
520 if( visited.test_set(n->_idx) ) return;
521 for( uint i=0; i<n->len(); i++ ) {
522 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
523 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
524 }
525 n->dump();
526 if (type_or_null(n) != NULL) {
527 tty->print(" "); type(n)->dump(); tty->cr();
528 }
529 }
530
531 #endif
532
533
534 //=============================================================================
535 //------------------------------PhaseValues------------------------------------
536 // Set minimum table size to "255"
537 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
538 NOT_PRODUCT( clear_new_values(); )
539 }
540
541 //------------------------------PhaseValues------------------------------------
542 // Set minimum table size to "255"
543 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
544 _table(&ptv->_table) {
545 NOT_PRODUCT( clear_new_values(); )
546 }
547
548 //------------------------------PhaseValues------------------------------------
549 // Used by +VerifyOpto. Clear out hash table but copy _types array.
550 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
551 _table(ptv->arena(),ptv->_table.size()) {
552 NOT_PRODUCT( clear_new_values(); )
553 }
554
555 //------------------------------~PhaseValues-----------------------------------
556 #ifndef PRODUCT
557 PhaseValues::~PhaseValues() {
558 _table.dump();
559
560 // Statistics for value progress and efficiency
561 if( PrintCompilation && Verbose && WizardMode ) {
562 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
563 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
564 if( made_transforms() != 0 ) {
565 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
566 } else {
567 tty->cr();
568 }
569 }
570 }
571 #endif
572
573 //------------------------------makecon----------------------------------------
574 ConNode* PhaseTransform::makecon(const Type *t) {
575 assert(t->singleton(), "must be a constant");
576 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
577 switch (t->base()) { // fast paths
578 case Type::Half:
579 case Type::Top: return (ConNode*) C->top();
580 case Type::Int: return intcon( t->is_int()->get_con() );
581 case Type::Long: return longcon( t->is_long()->get_con() );
582 }
583 if (t->is_zero_type())
584 return zerocon(t->basic_type());
585 return uncached_makecon(t);
586 }
587
588 //--------------------------uncached_makecon-----------------------------------
589 // Make an idealized constant - one of ConINode, ConPNode, etc.
590 ConNode* PhaseValues::uncached_makecon(const Type *t) {
591 assert(t->singleton(), "must be a constant");
592 ConNode* x = ConNode::make(C, t);
593 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
594 if (k == NULL) {
595 set_type(x, t); // Missed, provide type mapping
596 GrowableArray<Node_Notes*>* nna = C->node_note_array();
597 if (nna != NULL) {
598 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
599 loc->clear(); // do not put debug info on constants
600 }
601 } else {
602 x->destruct(); // Hit, destroy duplicate constant
603 x = k; // use existing constant
604 }
605 return x;
606 }
607
608 //------------------------------intcon-----------------------------------------
609 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
610 ConINode* PhaseTransform::intcon(int i) {
611 // Small integer? Check cache! Check that cached node is not dead
612 if (i >= _icon_min && i <= _icon_max) {
613 ConINode* icon = _icons[i-_icon_min];
614 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
615 return icon;
616 }
617 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
618 assert(icon->is_Con(), "");
619 if (i >= _icon_min && i <= _icon_max)
620 _icons[i-_icon_min] = icon; // Cache small integers
621 return icon;
622 }
623
624 //------------------------------longcon----------------------------------------
625 // Fast long constant.
626 ConLNode* PhaseTransform::longcon(jlong l) {
627 // Small integer? Check cache! Check that cached node is not dead
628 if (l >= _lcon_min && l <= _lcon_max) {
629 ConLNode* lcon = _lcons[l-_lcon_min];
630 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
631 return lcon;
632 }
633 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
634 assert(lcon->is_Con(), "");
635 if (l >= _lcon_min && l <= _lcon_max)
636 _lcons[l-_lcon_min] = lcon; // Cache small integers
637 return lcon;
638 }
639
640 //------------------------------zerocon-----------------------------------------
641 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
642 ConNode* PhaseTransform::zerocon(BasicType bt) {
643 assert((uint)bt <= _zcon_max, "domain check");
644 ConNode* zcon = _zcons[bt];
645 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
646 return zcon;
647 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
648 _zcons[bt] = zcon;
649 return zcon;
650 }
651
652
653
654 //=============================================================================
655 //------------------------------transform--------------------------------------
656 // Return a node which computes the same function as this node, but in a
657 // faster or cheaper fashion.
658 Node *PhaseGVN::transform( Node *n ) {
659 return transform_no_reclaim(n);
660 }
661
662 //------------------------------transform--------------------------------------
663 // Return a node which computes the same function as this node, but
664 // in a faster or cheaper fashion.
665 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
666 NOT_PRODUCT( set_transforms(); )
667
668 // Apply the Ideal call in a loop until it no longer applies
669 Node *k = n;
670 NOT_PRODUCT( uint loop_count = 0; )
671 while( 1 ) {
672 Node *i = k->Ideal(this, /*can_reshape=*/false);
673 if( !i ) break;
674 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
675 k = i;
676 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
677 }
678 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
679
680
681 // If brand new node, make space in type array.
682 ensure_type_or_null(k);
683
684 // Since I just called 'Value' to compute the set of run-time values
685 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
686 // cache Value. Later requests for the local phase->type of this Node can
687 // use the cached Value instead of suffering with 'bottom_type'.
688 const Type *t = k->Value(this); // Get runtime Value set
689 assert(t != NULL, "value sanity");
690 if (type_or_null(k) != t) {
691 #ifndef PRODUCT
692 // Do not count initial visit to node as a transformation
693 if (type_or_null(k) == NULL) {
694 inc_new_values();
695 set_progress();
696 }
697 #endif
698 set_type(k, t);
699 // If k is a TypeNode, capture any more-precise type permanently into Node
700 k->raise_bottom_type(t);
701 }
702
703 if( t->singleton() && !k->is_Con() ) {
704 NOT_PRODUCT( set_progress(); )
705 return makecon(t); // Turn into a constant
706 }
707
708 // Now check for Identities
709 Node *i = k->Identity(this); // Look for a nearby replacement
710 if( i != k ) { // Found? Return replacement!
711 NOT_PRODUCT( set_progress(); )
712 return i;
713 }
714
715 // Global Value Numbering
716 i = hash_find_insert(k); // Insert if new
717 if( i && (i != k) ) {
718 // Return the pre-existing node
719 NOT_PRODUCT( set_progress(); )
720 return i;
721 }
722
723 // Return Idealized original
724 return k;
725 }
726
727 #ifdef ASSERT
728 //------------------------------dead_loop_check--------------------------------
729 // Check for a simple dead loop when a data node references itself directly
730 // or through an other data node excluding cons and phis.
731 void PhaseGVN::dead_loop_check( Node *n ) {
732 // Phi may reference itself in a loop
733 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
734 // Do 2 levels check and only data inputs.
735 bool no_dead_loop = true;
736 uint cnt = n->req();
737 for (uint i = 1; i < cnt && no_dead_loop; i++) {
738 Node *in = n->in(i);
739 if (in == n) {
740 no_dead_loop = false;
741 } else if (in != NULL && !in->is_dead_loop_safe()) {
742 uint icnt = in->req();
743 for (uint j = 1; j < icnt && no_dead_loop; j++) {
744 if (in->in(j) == n || in->in(j) == in)
745 no_dead_loop = false;
746 }
747 }
748 }
749 if (!no_dead_loop) n->dump(3);
750 assert(no_dead_loop, "dead loop detected");
751 }
752 }
753 #endif
754
755 //=============================================================================
756 //------------------------------PhaseIterGVN-----------------------------------
757 // Initialize hash table to fresh and clean for +VerifyOpto
758 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ),
759 _delay_transform(false) {
760 }
761
762 //------------------------------PhaseIterGVN-----------------------------------
763 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
764 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
765 _worklist( igvn->_worklist ),
766 _delay_transform(igvn->_delay_transform)
767 {
768 }
769
770 //------------------------------PhaseIterGVN-----------------------------------
771 // Initialize with previous PhaseGVN info from Parser
772 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
773 _worklist(*C->for_igvn()),
774 _delay_transform(false)
775 {
776 uint max;
777
778 // Dead nodes in the hash table inherited from GVN were not treated as
779 // roots during def-use info creation; hence they represent an invisible
780 // use. Clear them out.
781 max = _table.size();
782 for( uint i = 0; i < max; ++i ) {
783 Node *n = _table.at(i);
784 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
785 if( n->is_top() ) continue;
786 assert( false, "Parse::remove_useless_nodes missed this node");
787 hash_delete(n);
788 }
789 }
790
791 // Any Phis or Regions on the worklist probably had uses that could not
792 // make more progress because the uses were made while the Phis and Regions
793 // were in half-built states. Put all uses of Phis and Regions on worklist.
794 max = _worklist.size();
795 for( uint j = 0; j < max; j++ ) {
796 Node *n = _worklist.at(j);
797 uint uop = n->Opcode();
798 if( uop == Op_Phi || uop == Op_Region ||
799 n->is_Type() ||
800 n->is_Mem() )
801 add_users_to_worklist(n);
802 }
803 }
804
805
806 #ifndef PRODUCT
807 void PhaseIterGVN::verify_step(Node* n) {
808 _verify_window[_verify_counter % _verify_window_size] = n;
809 ++_verify_counter;
810 ResourceMark rm;
811 ResourceArea *area = Thread::current()->resource_area();
812 VectorSet old_space(area), new_space(area);
813 if (C->unique() < 1000 ||
814 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
815 ++_verify_full_passes;
816 Node::verify_recur(C->root(), -1, old_space, new_space);
817 }
818 const int verify_depth = 4;
819 for ( int i = 0; i < _verify_window_size; i++ ) {
820 Node* n = _verify_window[i];
821 if ( n == NULL ) continue;
822 if( n->in(0) == NodeSentinel ) { // xform_idom
823 _verify_window[i] = n->in(1);
824 --i; continue;
825 }
826 // Typical fanout is 1-2, so this call visits about 6 nodes.
827 Node::verify_recur(n, verify_depth, old_space, new_space);
828 }
829 }
830 #endif
831
832
833 //------------------------------init_worklist----------------------------------
834 // Initialize worklist for each node.
835 void PhaseIterGVN::init_worklist( Node *n ) {
836 if( _worklist.member(n) ) return;
837 _worklist.push(n);
838 uint cnt = n->req();
839 for( uint i =0 ; i < cnt; i++ ) {
840 Node *m = n->in(i);
841 if( m ) init_worklist(m);
842 }
843 }
844
845 //------------------------------optimize---------------------------------------
846 void PhaseIterGVN::optimize() {
847 debug_only(uint num_processed = 0;);
848 #ifndef PRODUCT
849 {
850 _verify_counter = 0;
851 _verify_full_passes = 0;
852 for ( int i = 0; i < _verify_window_size; i++ ) {
853 _verify_window[i] = NULL;
854 }
855 }
856 #endif
857
858 #ifdef ASSERT
859 Node* prev = NULL;
860 uint rep_cnt = 0;
861 #endif
862 uint loop_count = 0;
863
864 // Pull from worklist; transform node;
865 // If node has changed: update edge info and put uses on worklist.
866 while( _worklist.size() ) {
867 Node *n = _worklist.pop();
868 if (++loop_count >= K * C->unique()) {
869 debug_only(n->dump(4);)
870 assert(false, "infinite loop in PhaseIterGVN::optimize");
871 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
872 return;
873 }
874 #ifdef ASSERT
875 if (n == prev) {
876 if (++rep_cnt > 3) {
877 n->dump(4);
878 assert(false, "loop in Ideal transformation");
879 }
880 } else {
881 rep_cnt = 0;
882 }
883 prev = n;
884 #endif
885 if (TraceIterativeGVN && Verbose) {
886 tty->print(" Pop ");
887 NOT_PRODUCT( n->dump(); )
888 debug_only(if( (num_processed++ % 100) == 0 ) _worklist.print_set();)
889 }
890
891 if (n->outcnt() != 0) {
892
893 #ifndef PRODUCT
894 uint wlsize = _worklist.size();
895 const Type* oldtype = type_or_null(n);
896 #endif //PRODUCT
897
898 Node *nn = transform_old(n);
899
900 #ifndef PRODUCT
901 if (TraceIterativeGVN) {
902 const Type* newtype = type_or_null(n);
903 if (nn != n) {
904 // print old node
905 tty->print("< ");
906 if (oldtype != newtype && oldtype != NULL) {
907 oldtype->dump();
908 }
909 do { tty->print("\t"); } while (tty->position() < 16);
910 tty->print("<");
911 n->dump();
912 }
913 if (oldtype != newtype || nn != n) {
914 // print new node and/or new type
915 if (oldtype == NULL) {
916 tty->print("* ");
917 } else if (nn != n) {
918 tty->print("> ");
919 } else {
920 tty->print("= ");
921 }
922 if (newtype == NULL) {
923 tty->print("null");
924 } else {
925 newtype->dump();
926 }
927 do { tty->print("\t"); } while (tty->position() < 16);
928 nn->dump();
929 }
930 if (Verbose && wlsize < _worklist.size()) {
931 tty->print(" Push {");
932 while (wlsize != _worklist.size()) {
933 Node* pushed = _worklist.at(wlsize++);
934 tty->print(" %d", pushed->_idx);
935 }
936 tty->print_cr(" }");
937 }
938 }
939 if( VerifyIterativeGVN && nn != n ) {
940 verify_step((Node*) NULL); // ignore n, it might be subsumed
941 }
942 #endif
943 } else if (!n->is_top()) {
944 remove_dead_node(n);
945 }
946 }
947
948 #ifndef PRODUCT
949 C->verify_graph_edges();
950 if( VerifyOpto && allow_progress() ) {
951 // Must turn off allow_progress to enable assert and break recursion
952 C->root()->verify();
953 { // Check if any progress was missed using IterGVN
954 // Def-Use info enables transformations not attempted in wash-pass
955 // e.g. Region/Phi cleanup, ...
956 // Null-check elision -- may not have reached fixpoint
957 // do not propagate to dominated nodes
958 ResourceMark rm;
959 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
960 // Fill worklist completely
961 igvn2.init_worklist(C->root());
962
963 igvn2.set_allow_progress(false);
964 igvn2.optimize();
965 igvn2.set_allow_progress(true);
966 }
967 }
968 if ( VerifyIterativeGVN && PrintOpto ) {
969 if ( _verify_counter == _verify_full_passes )
970 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
971 _verify_full_passes);
972 else
973 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
974 _verify_counter, _verify_full_passes);
975 }
976 #endif
977 }
978
979
980 //------------------register_new_node_with_optimizer---------------------------
981 // Register a new node with the optimizer. Update the types array, the def-use
982 // info. Put on worklist.
983 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
984 set_type_bottom(n);
985 _worklist.push(n);
986 if (orig != NULL) C->copy_node_notes_to(n, orig);
987 return n;
988 }
989
990 //------------------------------transform--------------------------------------
991 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
992 Node *PhaseIterGVN::transform( Node *n ) {
993 if (_delay_transform) {
994 // Register the node but don't optimize for now
995 register_new_node_with_optimizer(n);
996 return n;
997 }
998
999 // If brand new node, make space in type array, and give it a type.
1000 ensure_type_or_null(n);
1001 if (type_or_null(n) == NULL) {
1002 set_type_bottom(n);
1003 }
1004
1005 return transform_old(n);
1006 }
1007
1008 //------------------------------transform_old----------------------------------
1009 Node *PhaseIterGVN::transform_old( Node *n ) {
1010 #ifndef PRODUCT
1011 debug_only(uint loop_count = 0;);
1012 set_transforms();
1013 #endif
1014 // Remove 'n' from hash table in case it gets modified
1015 _table.hash_delete(n);
1016 if( VerifyIterativeGVN ) {
1017 assert( !_table.find_index(n->_idx), "found duplicate entry in table");
1018 }
1019
1020 // Apply the Ideal call in a loop until it no longer applies
1021 Node *k = n;
1022 DEBUG_ONLY(dead_loop_check(k);)
1023 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1024 Node *i = k->Ideal(this, /*can_reshape=*/true);
1025 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1026 #ifndef PRODUCT
1027 if( VerifyIterativeGVN )
1028 verify_step(k);
1029 if( i && VerifyOpto ) {
1030 if( !allow_progress() ) {
1031 if (i->is_Add() && i->outcnt() == 1) {
1032 // Switched input to left side because this is the only use
1033 } else if( i->is_If() && (i->in(0) == NULL) ) {
1034 // This IF is dead because it is dominated by an equivalent IF When
1035 // dominating if changed, info is not propagated sparsely to 'this'
1036 // Propagating this info further will spuriously identify other
1037 // progress.
1038 return i;
1039 } else
1040 set_progress();
1041 } else
1042 set_progress();
1043 }
1044 #endif
1045
1046 while( i ) {
1047 #ifndef PRODUCT
1048 debug_only( if( loop_count >= K ) i->dump(4); )
1049 assert(loop_count < K, "infinite loop in PhaseIterGVN::transform");
1050 debug_only( loop_count++; )
1051 #endif
1052 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1053 // Made a change; put users of original Node on worklist
1054 add_users_to_worklist( k );
1055 // Replacing root of transform tree?
1056 if( k != i ) {
1057 // Make users of old Node now use new.
1058 subsume_node( k, i );
1059 k = i;
1060 }
1061 DEBUG_ONLY(dead_loop_check(k);)
1062 // Try idealizing again
1063 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1064 i = k->Ideal(this, /*can_reshape=*/true);
1065 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1066 #ifndef PRODUCT
1067 if( VerifyIterativeGVN )
1068 verify_step(k);
1069 if( i && VerifyOpto ) set_progress();
1070 #endif
1071 }
1072
1073 // If brand new node, make space in type array.
1074 ensure_type_or_null(k);
1075
1076 // See what kind of values 'k' takes on at runtime
1077 const Type *t = k->Value(this);
1078 assert(t != NULL, "value sanity");
1079
1080 // Since I just called 'Value' to compute the set of run-time values
1081 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1082 // cache Value. Later requests for the local phase->type of this Node can
1083 // use the cached Value instead of suffering with 'bottom_type'.
1084 if (t != type_or_null(k)) {
1085 NOT_PRODUCT( set_progress(); )
1086 NOT_PRODUCT( inc_new_values();)
1087 set_type(k, t);
1088 // If k is a TypeNode, capture any more-precise type permanently into Node
1089 k->raise_bottom_type(t);
1090 // Move users of node to worklist
1091 add_users_to_worklist( k );
1092 }
1093
1094 // If 'k' computes a constant, replace it with a constant
1095 if( t->singleton() && !k->is_Con() ) {
1096 NOT_PRODUCT( set_progress(); )
1097 Node *con = makecon(t); // Make a constant
1098 add_users_to_worklist( k );
1099 subsume_node( k, con ); // Everybody using k now uses con
1100 return con;
1101 }
1102
1103 // Now check for Identities
1104 i = k->Identity(this); // Look for a nearby replacement
1105 if( i != k ) { // Found? Return replacement!
1106 NOT_PRODUCT( set_progress(); )
1107 add_users_to_worklist( k );
1108 subsume_node( k, i ); // Everybody using k now uses i
1109 return i;
1110 }
1111
1112 // Global Value Numbering
1113 i = hash_find_insert(k); // Check for pre-existing node
1114 if( i && (i != k) ) {
1115 // Return the pre-existing node if it isn't dead
1116 NOT_PRODUCT( set_progress(); )
1117 add_users_to_worklist( k );
1118 subsume_node( k, i ); // Everybody using k now uses i
1119 return i;
1120 }
1121
1122 // Return Idealized original
1123 return k;
1124 }
1125
1126 //---------------------------------saturate------------------------------------
1127 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1128 const Type* limit_type) const {
1129 return new_type->narrow(old_type);
1130 }
1131
1132 //------------------------------remove_globally_dead_node----------------------
1133 // Kill a globally dead Node. All uses are also globally dead and are
1134 // aggressively trimmed.
1135 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1136 assert(dead != C->root(), "killing root, eh?");
1137 if (dead->is_top()) return;
1138 NOT_PRODUCT( set_progress(); )
1139 // Remove from iterative worklist
1140 _worklist.remove(dead);
1141 if (!dead->is_Con()) { // Don't kill cons but uses
1142 // Remove from hash table
1143 _table.hash_delete( dead );
1144 // Smash all inputs to 'dead', isolating him completely
1145 for( uint i = 0; i < dead->req(); i++ ) {
1146 Node *in = dead->in(i);
1147 if( in ) { // Points to something?
1148 dead->set_req(i,NULL); // Kill the edge
1149 if (in->outcnt() == 0 && in != C->top()) {// Made input go dead?
1150 remove_dead_node(in); // Recursively remove
1151 } else if (in->outcnt() == 1 &&
1152 in->has_special_unique_user()) {
1153 _worklist.push(in->unique_out());
1154 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1155 if( in->Opcode() == Op_Region )
1156 _worklist.push(in);
1157 else if( in->is_Store() ) {
1158 DUIterator_Fast imax, i = in->fast_outs(imax);
1159 _worklist.push(in->fast_out(i));
1160 i++;
1161 if(in->outcnt() == 2) {
1162 _worklist.push(in->fast_out(i));
1163 i++;
1164 }
1165 assert(!(i < imax), "sanity");
1166 }
1167 }
1168 }
1169 }
1170
1171 if (dead->is_macro()) {
1172 C->remove_macro_node(dead);
1173 }
1174 }
1175 // Aggressively kill globally dead uses
1176 // (Cannot use DUIterator_Last because of the indefinite number
1177 // of edge deletions per loop trip.)
1178 while (dead->outcnt() > 0) {
1179 remove_globally_dead_node(dead->raw_out(0));
1180 }
1181 }
1182
1183 //------------------------------subsume_node-----------------------------------
1184 // Remove users from node 'old' and add them to node 'nn'.
1185 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1186 assert( old != hash_find(old), "should already been removed" );
1187 assert( old != C->top(), "cannot subsume top node");
1188 // Copy debug or profile information to the new version:
1189 C->copy_node_notes_to(nn, old);
1190 // Move users of node 'old' to node 'nn'
1191 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1192 Node* use = old->last_out(i); // for each use...
1193 // use might need re-hashing (but it won't if it's a new node)
1194 bool is_in_table = _table.hash_delete( use );
1195 // Update use-def info as well
1196 // We remove all occurrences of old within use->in,
1197 // so as to avoid rehashing any node more than once.
1198 // The hash table probe swamps any outer loop overhead.
1199 uint num_edges = 0;
1200 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1201 if (use->in(j) == old) {
1202 use->set_req(j, nn);
1203 ++num_edges;
1204 }
1205 }
1206 // Insert into GVN hash table if unique
1207 // If a duplicate, 'use' will be cleaned up when pulled off worklist
1208 if( is_in_table ) {
1209 hash_find_insert(use);
1210 }
1211 i -= num_edges; // we deleted 1 or more copies of this edge
1212 }
1213
1214 // Smash all inputs to 'old', isolating him completely
1215 Node *temp = new (C, 1) Node(1);
1216 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1217 remove_dead_node( old );
1218 temp->del_req(0); // Yank bogus edge
1219 #ifndef PRODUCT
1220 if( VerifyIterativeGVN ) {
1221 for ( int i = 0; i < _verify_window_size; i++ ) {
1222 if ( _verify_window[i] == old )
1223 _verify_window[i] = nn;
1224 }
1225 }
1226 #endif
1227 _worklist.remove(temp); // this can be necessary
1228 temp->destruct(); // reuse the _idx of this little guy
1229 }
1230
1231 //------------------------------add_users_to_worklist--------------------------
1232 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1233 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1234 _worklist.push(n->fast_out(i)); // Push on worklist
1235 }
1236 }
1237
1238 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1239 add_users_to_worklist0(n);
1240
1241 // Move users of node to worklist
1242 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1243 Node* use = n->fast_out(i); // Get use
1244
1245 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1246 use->is_Store() ) // Enable store/load same address
1247 add_users_to_worklist0(use);
1248
1249 // If we changed the receiver type to a call, we need to revisit
1250 // the Catch following the call. It's looking for a non-NULL
1251 // receiver to know when to enable the regular fall-through path
1252 // in addition to the NullPtrException path.
1253 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1254 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
1255 if (p != NULL) {
1256 add_users_to_worklist0(p);
1257 }
1258 }
1259
1260 if( use->is_Cmp() ) { // Enable CMP/BOOL optimization
1261 add_users_to_worklist(use); // Put Bool on worklist
1262 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1263 // phi merging either 0 or 1 onto the worklist
1264 if (use->outcnt() > 0) {
1265 Node* bol = use->raw_out(0);
1266 if (bol->outcnt() > 0) {
1267 Node* iff = bol->raw_out(0);
1268 if (iff->outcnt() == 2) {
1269 Node* ifproj0 = iff->raw_out(0);
1270 Node* ifproj1 = iff->raw_out(1);
1271 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1272 Node* region0 = ifproj0->raw_out(0);
1273 Node* region1 = ifproj1->raw_out(0);
1274 if( region0 == region1 )
1275 add_users_to_worklist0(region0);
1276 }
1277 }
1278 }
1279 }
1280 }
1281
1282 uint use_op = use->Opcode();
1283 // If changed Cast input, check Phi users for simple cycles
1284 if( use->is_ConstraintCast() || use->is_CheckCastPP() ) {
1285 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1286 Node* u = use->fast_out(i2);
1287 if (u->is_Phi())
1288 _worklist.push(u);
1289 }
1290 }
1291 // If changed LShift inputs, check RShift users for useless sign-ext
1292 if( use_op == Op_LShiftI ) {
1293 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1294 Node* u = use->fast_out(i2);
1295 if (u->Opcode() == Op_RShiftI)
1296 _worklist.push(u);
1297 }
1298 }
1299 // If changed AddP inputs, check Stores for loop invariant
1300 if( use_op == Op_AddP ) {
1301 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1302 Node* u = use->fast_out(i2);
1303 if (u->is_Mem())
1304 _worklist.push(u);
1305 }
1306 }
1307 // If changed initialization activity, check dependent Stores
1308 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1309 InitializeNode* init = use->as_Allocate()->initialization();
1310 if (init != NULL) {
1311 Node* imem = init->proj_out(TypeFunc::Memory);
1312 if (imem != NULL) add_users_to_worklist0(imem);
1313 }
1314 }
1315 if (use_op == Op_Initialize) {
1316 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
1317 if (imem != NULL) add_users_to_worklist0(imem);
1318 }
1319 }
1320 }
1321
1322 //=============================================================================
1323 #ifndef PRODUCT
1324 uint PhaseCCP::_total_invokes = 0;
1325 uint PhaseCCP::_total_constants = 0;
1326 #endif
1327 //------------------------------PhaseCCP---------------------------------------
1328 // Conditional Constant Propagation, ala Wegman & Zadeck
1329 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1330 NOT_PRODUCT( clear_constants(); )
1331 assert( _worklist.size() == 0, "" );
1332 // Clear out _nodes from IterGVN. Must be clear to transform call.
1333 _nodes.clear(); // Clear out from IterGVN
1334 analyze();
1335 }
1336
1337 #ifndef PRODUCT
1338 //------------------------------~PhaseCCP--------------------------------------
1339 PhaseCCP::~PhaseCCP() {
1340 inc_invokes();
1341 _total_constants += count_constants();
1342 }
1343 #endif
1344
1345
1346 #ifdef ASSERT
1347 static bool ccp_type_widens(const Type* t, const Type* t0) {
1348 assert(t->meet(t0) == t, "Not monotonic");
1349 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1350 case Type::Int:
1351 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1352 break;
1353 case Type::Long:
1354 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1355 break;
1356 }
1357 return true;
1358 }
1359 #endif //ASSERT
1360
1361 //------------------------------analyze----------------------------------------
1362 void PhaseCCP::analyze() {
1363 // Initialize all types to TOP, optimistic analysis
1364 for (int i = C->unique() - 1; i >= 0; i--) {
1365 _types.map(i,Type::TOP);
1366 }
1367
1368 // Push root onto worklist
1369 Unique_Node_List worklist;
1370 worklist.push(C->root());
1371
1372 // Pull from worklist; compute new value; push changes out.
1373 // This loop is the meat of CCP.
1374 while( worklist.size() ) {
1375 Node *n = worklist.pop();
1376 const Type *t = n->Value(this);
1377 if (t != type(n)) {
1378 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1379 #ifndef PRODUCT
1380 if( TracePhaseCCP ) {
1381 t->dump();
1382 do { tty->print("\t"); } while (tty->position() < 16);
1383 n->dump();
1384 }
1385 #endif
1386 set_type(n, t);
1387 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1388 Node* m = n->fast_out(i); // Get user
1389 if( m->is_Region() ) { // New path to Region? Must recheck Phis too
1390 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1391 Node* p = m->fast_out(i2); // Propagate changes to uses
1392 if( p->bottom_type() != type(p) ) // If not already bottomed out
1393 worklist.push(p); // Propagate change to user
1394 }
1395 }
1396 // If we changed the receiver type to a call, we need to revisit
1397 // the Catch following the call. It's looking for a non-NULL
1398 // receiver to know when to enable the regular fall-through path
1399 // in addition to the NullPtrException path
1400 if (m->is_Call()) {
1401 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1402 Node* p = m->fast_out(i2); // Propagate changes to uses
1403 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1)
1404 worklist.push(p->unique_out());
1405 }
1406 }
1407 if( m->bottom_type() != type(m) ) // If not already bottomed out
1408 worklist.push(m); // Propagate change to user
1409 }
1410 }
1411 }
1412 }
1413
1414 //------------------------------do_transform-----------------------------------
1415 // Top level driver for the recursive transformer
1416 void PhaseCCP::do_transform() {
1417 // Correct leaves of new-space Nodes; they point to old-space.
1418 C->set_root( transform(C->root())->as_Root() );
1419 assert( C->top(), "missing TOP node" );
1420 assert( C->root(), "missing root" );
1421 }
1422
1423 //------------------------------transform--------------------------------------
1424 // Given a Node in old-space, clone him into new-space.
1425 // Convert any of his old-space children into new-space children.
1426 Node *PhaseCCP::transform( Node *n ) {
1427 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1428 if( new_node != NULL )
1429 return new_node; // Been there, done that, return old answer
1430 new_node = transform_once(n); // Check for constant
1431 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1432
1433 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1434 GrowableArray <Node *> trstack(C->unique() >> 1);
1435
1436 trstack.push(new_node); // Process children of cloned node
1437 while ( trstack.is_nonempty() ) {
1438 Node *clone = trstack.pop();
1439 uint cnt = clone->req();
1440 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1441 Node *input = clone->in(i);
1442 if( input != NULL ) { // Ignore NULLs
1443 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1444 if( new_input == NULL ) {
1445 new_input = transform_once(input); // Check for constant
1446 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1447 trstack.push(new_input);
1448 }
1449 assert( new_input == clone->in(i), "insanity check");
1450 }
1451 }
1452 }
1453 return new_node;
1454 }
1455
1456
1457 //------------------------------transform_once---------------------------------
1458 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1459 Node *PhaseCCP::transform_once( Node *n ) {
1460 const Type *t = type(n);
1461 // Constant? Use constant Node instead
1462 if( t->singleton() ) {
1463 Node *nn = n; // Default is to return the original constant
1464 if( t == Type::TOP ) {
1465 // cache my top node on the Compile instance
1466 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1467 C->set_cached_top_node( ConNode::make(C, Type::TOP) );
1468 set_type(C->top(), Type::TOP);
1469 }
1470 nn = C->top();
1471 }
1472 if( !n->is_Con() ) {
1473 if( t != Type::TOP ) {
1474 nn = makecon(t); // ConNode::make(t);
1475 NOT_PRODUCT( inc_constants(); )
1476 } else if( n->is_Region() ) { // Unreachable region
1477 // Note: nn == C->top()
1478 n->set_req(0, NULL); // Cut selfreference
1479 // Eagerly remove dead phis to avoid phis copies creation.
1480 for (DUIterator i = n->outs(); n->has_out(i); i++) {
1481 Node* m = n->out(i);
1482 if( m->is_Phi() ) {
1483 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1484 replace_node(m, nn);
1485 --i; // deleted this phi; rescan starting with next position
1486 }
1487 }
1488 }
1489 replace_node(n,nn); // Update DefUse edges for new constant
1490 }
1491 return nn;
1492 }
1493
1494 // If x is a TypeNode, capture any more-precise type permanently into Node
1495 if (t != n->bottom_type()) {
1496 hash_delete(n); // changing bottom type may force a rehash
1497 n->raise_bottom_type(t);
1498 _worklist.push(n); // n re-enters the hash table via the worklist
1499 }
1500
1501 // Idealize graph using DU info. Must clone() into new-space.
1502 // DU info is generally used to show profitability, progress or safety
1503 // (but generally not needed for correctness).
1504 Node *nn = n->Ideal_DU_postCCP(this);
1505
1506 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1507 switch( n->Opcode() ) {
1508 case Op_FastLock: // Revisit FastLocks for lock coarsening
1509 case Op_If:
1510 case Op_CountedLoopEnd:
1511 case Op_Region:
1512 case Op_Loop:
1513 case Op_CountedLoop:
1514 case Op_Conv2B:
1515 case Op_Opaque1:
1516 case Op_Opaque2:
1517 _worklist.push(n);
1518 break;
1519 default:
1520 break;
1521 }
1522 if( nn ) {
1523 _worklist.push(n);
1524 // Put users of 'n' onto worklist for second igvn transform
1525 add_users_to_worklist(n);
1526 return nn;
1527 }
1528
1529 return n;
1530 }
1531
1532 //---------------------------------saturate------------------------------------
1533 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1534 const Type* limit_type) const {
1535 const Type* wide_type = new_type->widen(old_type, limit_type);
1536 if (wide_type != new_type) { // did we widen?
1537 // If so, we may have widened beyond the limit type. Clip it back down.
1538 new_type = wide_type->filter(limit_type);
1539 }
1540 return new_type;
1541 }
1542
1543 //------------------------------print_statistics-------------------------------
1544 #ifndef PRODUCT
1545 void PhaseCCP::print_statistics() {
1546 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1547 }
1548 #endif
1549
1550
1551 //=============================================================================
1552 #ifndef PRODUCT
1553 uint PhasePeephole::_total_peepholes = 0;
1554 #endif
1555 //------------------------------PhasePeephole----------------------------------
1556 // Conditional Constant Propagation, ala Wegman & Zadeck
1557 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1558 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1559 NOT_PRODUCT( clear_peepholes(); )
1560 }
1561
1562 #ifndef PRODUCT
1563 //------------------------------~PhasePeephole---------------------------------
1564 PhasePeephole::~PhasePeephole() {
1565 _total_peepholes += count_peepholes();
1566 }
1567 #endif
1568
1569 //------------------------------transform--------------------------------------
1570 Node *PhasePeephole::transform( Node *n ) {
1571 ShouldNotCallThis();
1572 return NULL;
1573 }
1574
1575 //------------------------------do_transform-----------------------------------
1576 void PhasePeephole::do_transform() {
1577 bool method_name_not_printed = true;
1578
1579 // Examine each basic block
1580 for( uint block_number = 1; block_number < _cfg._num_blocks; ++block_number ) {
1581 Block *block = _cfg._blocks[block_number];
1582 bool block_not_printed = true;
1583
1584 // and each instruction within a block
1585 uint end_index = block->_nodes.size();
1586 // block->end_idx() not valid after PhaseRegAlloc
1587 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
1588 Node *n = block->_nodes.at(instruction_index);
1589 if( n->is_Mach() ) {
1590 MachNode *m = n->as_Mach();
1591 int deleted_count = 0;
1592 // check for peephole opportunities
1593 MachNode *m2 = m->peephole( block, instruction_index, _regalloc, deleted_count, C );
1594 if( m2 != NULL ) {
1595 #ifndef PRODUCT
1596 if( PrintOptoPeephole ) {
1597 // Print method, first time only
1598 if( C->method() && method_name_not_printed ) {
1599 C->method()->print_short_name(); tty->cr();
1600 method_name_not_printed = false;
1601 }
1602 // Print this block
1603 if( Verbose && block_not_printed) {
1604 tty->print_cr("in block");
1605 block->dump();
1606 block_not_printed = false;
1607 }
1608 // Print instructions being deleted
1609 for( int i = (deleted_count - 1); i >= 0; --i ) {
1610 block->_nodes.at(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
1611 }
1612 tty->print_cr("replaced with");
1613 // Print new instruction
1614 m2->format(_regalloc);
1615 tty->print("\n\n");
1616 }
1617 #endif
1618 // Remove old nodes from basic block and update instruction_index
1619 // (old nodes still exist and may have edges pointing to them
1620 // as register allocation info is stored in the allocator using
1621 // the node index to live range mappings.)
1622 uint safe_instruction_index = (instruction_index - deleted_count);
1623 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
1624 block->_nodes.remove( instruction_index );
1625 }
1626 // install new node after safe_instruction_index
1627 block->_nodes.insert( safe_instruction_index + 1, m2 );
1628 end_index = block->_nodes.size() - 1; // Recompute new block size
1629 NOT_PRODUCT( inc_peepholes(); )
1630 }
1631 }
1632 }
1633 }
1634 }
1635
1636 //------------------------------print_statistics-------------------------------
1637 #ifndef PRODUCT
1638 void PhasePeephole::print_statistics() {
1639 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
1640 }
1641 #endif
1642
1643
1644 //=============================================================================
1645 //------------------------------set_req_X--------------------------------------
1646 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
1647 assert( is_not_dead(n), "can not use dead node");
1648 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
1649 Node *old = in(i);
1650 set_req(i, n);
1651
1652 // old goes dead?
1653 if( old ) {
1654 switch (old->outcnt()) {
1655 case 0:
1656 // Put into the worklist to kill later. We do not kill it now because the
1657 // recursive kill will delete the current node (this) if dead-loop exists
1658 if (!old->is_top())
1659 igvn->_worklist.push( old );
1660 break;
1661 case 1:
1662 if( old->is_Store() || old->has_special_unique_user() )
1663 igvn->add_users_to_worklist( old );
1664 break;
1665 case 2:
1666 if( old->is_Store() )
1667 igvn->add_users_to_worklist( old );
1668 if( old->Opcode() == Op_Region )
1669 igvn->_worklist.push(old);
1670 break;
1671 case 3:
1672 if( old->Opcode() == Op_Region ) {
1673 igvn->_worklist.push(old);
1674 igvn->add_users_to_worklist( old );
1675 }
1676 break;
1677 default:
1678 break;
1679 }
1680 }
1681
1682 }
1683
1684 //-------------------------------replace_by-----------------------------------
1685 // Using def-use info, replace one node for another. Follow the def-use info
1686 // to all users of the OLD node. Then make all uses point to the NEW node.
1687 void Node::replace_by(Node *new_node) {
1688 assert(!is_top(), "top node has no DU info");
1689 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
1690 Node* use = last_out(i);
1691 uint uses_found = 0;
1692 for (uint j = 0; j < use->len(); j++) {
1693 if (use->in(j) == this) {
1694 if (j < use->req())
1695 use->set_req(j, new_node);
1696 else use->set_prec(j, new_node);
1697 uses_found++;
1698 }
1699 }
1700 i -= uses_found; // we deleted 1 or more copies of this edge
1701 }
1702 }
1703
1704 //=============================================================================
1705 //-----------------------------------------------------------------------------
1706 void Type_Array::grow( uint i ) {
1707 if( !_max ) {
1708 _max = 1;
1709 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
1710 _types[0] = NULL;
1711 }
1712 uint old = _max;
1713 while( i >= _max ) _max <<= 1; // Double to fit
1714 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
1715 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
1716 }
1717
1718 //------------------------------dump-------------------------------------------
1719 #ifndef PRODUCT
1720 void Type_Array::dump() const {
1721 uint max = Size();
1722 for( uint i = 0; i < max; i++ ) {
1723 if( _types[i] != NULL ) {
1724 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
1725 }
1726 }
1727 }
1728 #endif