1 /*
2 * Copyright (c) 1997, 2018, 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 "gc/shared/barrierSet.hpp"
27 #include "gc/shared/c2/barrierSetC2.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "opto/block.hpp"
31 #include "opto/callnode.hpp"
32 #include "opto/castnode.hpp"
33 #include "opto/cfgnode.hpp"
34 #include "opto/idealGraphPrinter.hpp"
35 #include "opto/loopnode.hpp"
36 #include "opto/machnode.hpp"
37 #include "opto/opcodes.hpp"
38 #include "opto/phaseX.hpp"
39 #include "opto/regalloc.hpp"
40 #include "opto/rootnode.hpp"
41 #include "utilities/macros.hpp"
42
43 //=============================================================================
44 #define NODE_HASH_MINIMUM_SIZE 255
45 //------------------------------NodeHash---------------------------------------
46 NodeHash::NodeHash(uint est_max_size) :
47 _a(Thread::current()->resource_area()),
48 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
49 _inserts(0), _insert_limit( insert_limit() ),
50 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ) // (Node**)_a->Amalloc(_max * sizeof(Node*)) ),
51 #ifndef PRODUCT
52 , _grows(0),_look_probes(0), _lookup_hits(0), _lookup_misses(0),
53 _insert_probes(0), _delete_probes(0), _delete_hits(0), _delete_misses(0),
54 _total_inserts(0), _total_insert_probes(0)
55 #endif
56 {
57 // _sentinel must be in the current node space
58 _sentinel = new ProjNode(NULL, TypeFunc::Control);
59 memset(_table,0,sizeof(Node*)*_max);
60 }
61
62 //------------------------------NodeHash---------------------------------------
63 NodeHash::NodeHash(Arena *arena, uint est_max_size) :
64 _a(arena),
65 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
66 _inserts(0), _insert_limit( insert_limit() ),
67 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) )
68 #ifndef PRODUCT
69 , _grows(0),_look_probes(0), _lookup_hits(0), _lookup_misses(0),
70 _insert_probes(0), _delete_probes(0), _delete_hits(0), _delete_misses(0),
71 _total_inserts(0), _total_insert_probes(0)
72 #endif
73 {
74 // _sentinel must be in the current node space
75 _sentinel = new ProjNode(NULL, TypeFunc::Control);
76 memset(_table,0,sizeof(Node*)*_max);
77 }
78
79 //------------------------------NodeHash---------------------------------------
80 NodeHash::NodeHash(NodeHash *nh) {
81 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
82 // just copy in all the fields
83 *this = *nh;
84 // nh->_sentinel must be in the current node space
85 }
86
87 void NodeHash::replace_with(NodeHash *nh) {
88 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
89 // just copy in all the fields
90 *this = *nh;
91 // nh->_sentinel must be in the current node space
92 }
93
94 //------------------------------hash_find--------------------------------------
95 // Find in hash table
96 Node *NodeHash::hash_find( const Node *n ) {
97 // ((Node*)n)->set_hash( n->hash() );
98 uint hash = n->hash();
99 if (hash == Node::NO_HASH) {
100 NOT_PRODUCT( _lookup_misses++ );
101 return NULL;
102 }
103 uint key = hash & (_max-1);
104 uint stride = key | 0x01;
105 NOT_PRODUCT( _look_probes++ );
106 Node *k = _table[key]; // Get hashed value
107 if( !k ) { // ?Miss?
108 NOT_PRODUCT( _lookup_misses++ );
109 return NULL; // Miss!
110 }
111
112 int op = n->Opcode();
113 uint req = n->req();
114 while( 1 ) { // While probing hash table
115 if( k->req() == req && // Same count of inputs
116 k->Opcode() == op ) { // Same Opcode
117 for( uint i=0; i<req; i++ )
118 if( n->in(i)!=k->in(i)) // Different inputs?
119 goto collision; // "goto" is a speed hack...
120 if( n->cmp(*k) ) { // Check for any special bits
121 NOT_PRODUCT( _lookup_hits++ );
122 return k; // Hit!
123 }
124 }
125 collision:
126 NOT_PRODUCT( _look_probes++ );
127 key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime
128 k = _table[key]; // Get hashed value
129 if( !k ) { // ?Miss?
130 NOT_PRODUCT( _lookup_misses++ );
131 return NULL; // Miss!
132 }
133 }
134 ShouldNotReachHere();
135 return NULL;
136 }
137
138 //------------------------------hash_find_insert-------------------------------
139 // Find in hash table, insert if not already present
140 // Used to preserve unique entries in hash table
141 Node *NodeHash::hash_find_insert( Node *n ) {
142 // n->set_hash( );
143 uint hash = n->hash();
144 if (hash == Node::NO_HASH) {
145 NOT_PRODUCT( _lookup_misses++ );
146 return NULL;
147 }
148 uint key = hash & (_max-1);
149 uint stride = key | 0x01; // stride must be relatively prime to table siz
150 uint first_sentinel = 0; // replace a sentinel if seen.
151 NOT_PRODUCT( _look_probes++ );
152 Node *k = _table[key]; // Get hashed value
153 if( !k ) { // ?Miss?
154 NOT_PRODUCT( _lookup_misses++ );
155 _table[key] = n; // Insert into table!
156 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
157 check_grow(); // Grow table if insert hit limit
158 return NULL; // Miss!
159 }
160 else if( k == _sentinel ) {
161 first_sentinel = key; // Can insert here
162 }
163
164 int op = n->Opcode();
165 uint req = n->req();
166 while( 1 ) { // While probing hash table
167 if( k->req() == req && // Same count of inputs
168 k->Opcode() == op ) { // Same Opcode
169 for( uint i=0; i<req; i++ )
170 if( n->in(i)!=k->in(i)) // Different inputs?
171 goto collision; // "goto" is a speed hack...
172 if( n->cmp(*k) ) { // Check for any special bits
173 NOT_PRODUCT( _lookup_hits++ );
174 return k; // Hit!
175 }
176 }
177 collision:
178 NOT_PRODUCT( _look_probes++ );
179 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
180 k = _table[key]; // Get hashed value
181 if( !k ) { // ?Miss?
182 NOT_PRODUCT( _lookup_misses++ );
183 key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel?
184 _table[key] = n; // Insert into table!
185 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
186 check_grow(); // Grow table if insert hit limit
187 return NULL; // Miss!
188 }
189 else if( first_sentinel == 0 && k == _sentinel ) {
190 first_sentinel = key; // Can insert here
191 }
192
193 }
194 ShouldNotReachHere();
195 return NULL;
196 }
197
198 //------------------------------hash_insert------------------------------------
199 // Insert into hash table
200 void NodeHash::hash_insert( Node *n ) {
201 // // "conflict" comments -- print nodes that conflict
202 // bool conflict = false;
203 // n->set_hash();
204 uint hash = n->hash();
205 if (hash == Node::NO_HASH) {
206 return;
207 }
208 check_grow();
209 uint key = hash & (_max-1);
210 uint stride = key | 0x01;
211
212 while( 1 ) { // While probing hash table
213 NOT_PRODUCT( _insert_probes++ );
214 Node *k = _table[key]; // Get hashed value
215 if( !k || (k == _sentinel) ) break; // Found a slot
216 assert( k != n, "already inserted" );
217 // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; }
218 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
219 }
220 _table[key] = n; // Insert into table!
221 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
222 // if( conflict ) { n->dump(); }
223 }
224
225 //------------------------------hash_delete------------------------------------
226 // Replace in hash table with sentinel
227 bool NodeHash::hash_delete( const Node *n ) {
228 Node *k;
229 uint hash = n->hash();
230 if (hash == Node::NO_HASH) {
231 NOT_PRODUCT( _delete_misses++ );
232 return false;
233 }
234 uint key = hash & (_max-1);
235 uint stride = key | 0x01;
236 debug_only( uint counter = 0; );
237 for( ; /* (k != NULL) && (k != _sentinel) */; ) {
238 debug_only( counter++ );
239 NOT_PRODUCT( _delete_probes++ );
240 k = _table[key]; // Get hashed value
241 if( !k ) { // Miss?
242 NOT_PRODUCT( _delete_misses++ );
243 #ifdef ASSERT
244 if( VerifyOpto ) {
245 for( uint i=0; i < _max; i++ )
246 assert( _table[i] != n, "changed edges with rehashing" );
247 }
248 #endif
249 return false; // Miss! Not in chain
250 }
251 else if( n == k ) {
252 NOT_PRODUCT( _delete_hits++ );
253 _table[key] = _sentinel; // Hit! Label as deleted entry
254 debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table.
255 return true;
256 }
257 else {
258 // collision: move through table with prime offset
259 key = (key + stride/*7*/) & (_max-1);
260 assert( counter <= _insert_limit, "Cycle in hash-table");
261 }
262 }
263 ShouldNotReachHere();
264 return false;
265 }
266
267 //------------------------------round_up---------------------------------------
268 // Round up to nearest power of 2
269 uint NodeHash::round_up( uint x ) {
270 x += (x>>2); // Add 25% slop
271 if( x <16 ) return 16; // Small stuff
272 uint i=16;
273 while( i < x ) i <<= 1; // Double to fit
274 return i; // Return hash table size
275 }
276
277 //------------------------------grow-------------------------------------------
278 // Grow _table to next power of 2 and insert old entries
279 void NodeHash::grow() {
280 // Record old state
281 uint old_max = _max;
282 Node **old_table = _table;
283 // Construct new table with twice the space
284 #ifndef PRODUCT
285 _grows++;
286 _total_inserts += _inserts;
287 _total_insert_probes += _insert_probes;
288 _insert_probes = 0;
289 #endif
290 _inserts = 0;
291 _max = _max << 1;
292 _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) );
293 memset(_table,0,sizeof(Node*)*_max);
294 _insert_limit = insert_limit();
295 // Insert old entries into the new table
296 for( uint i = 0; i < old_max; i++ ) {
297 Node *m = *old_table++;
298 if( !m || m == _sentinel ) continue;
299 debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table.
300 hash_insert(m);
301 }
302 }
303
304 //------------------------------clear------------------------------------------
305 // Clear all entries in _table to NULL but keep storage
306 void NodeHash::clear() {
307 #ifdef ASSERT
308 // Unlock all nodes upon removal from table.
309 for (uint i = 0; i < _max; i++) {
310 Node* n = _table[i];
311 if (!n || n == _sentinel) continue;
312 n->exit_hash_lock();
313 }
314 #endif
315
316 memset( _table, 0, _max * sizeof(Node*) );
317 }
318
319 //-----------------------remove_useless_nodes----------------------------------
320 // Remove useless nodes from value table,
321 // implementation does not depend on hash function
322 void NodeHash::remove_useless_nodes(VectorSet &useful) {
323
324 // Dead nodes in the hash table inherited from GVN should not replace
325 // existing nodes, remove dead nodes.
326 uint max = size();
327 Node *sentinel_node = sentinel();
328 for( uint i = 0; i < max; ++i ) {
329 Node *n = at(i);
330 if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) {
331 debug_only(n->exit_hash_lock()); // Unlock the node when removed
332 _table[i] = sentinel_node; // Replace with placeholder
333 }
334 }
335 }
336
337
338 void NodeHash::check_no_speculative_types() {
339 #ifdef ASSERT
340 uint max = size();
341 Node *sentinel_node = sentinel();
342 for (uint i = 0; i < max; ++i) {
343 Node *n = at(i);
344 if(n != NULL && n != sentinel_node && n->is_Type() && n->outcnt() > 0) {
345 TypeNode* tn = n->as_Type();
346 const Type* t = tn->type();
347 const Type* t_no_spec = t->remove_speculative();
348 assert(t == t_no_spec, "dead node in hash table or missed node during speculative cleanup");
349 }
350 }
351 #endif
352 }
353
354 #ifndef PRODUCT
355 //------------------------------dump-------------------------------------------
356 // Dump statistics for the hash table
357 void NodeHash::dump() {
358 _total_inserts += _inserts;
359 _total_insert_probes += _insert_probes;
360 if (PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0)) {
361 if (WizardMode) {
362 for (uint i=0; i<_max; i++) {
363 if (_table[i])
364 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
365 }
366 }
367 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max);
368 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
369 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
370 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
371 // sentinels increase lookup cost, but not insert cost
372 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
373 assert( _inserts+(_inserts>>3) < _max, "table too full" );
374 assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
375 }
376 }
377
378 Node *NodeHash::find_index(uint idx) { // For debugging
379 // Find an entry by its index value
380 for( uint i = 0; i < _max; i++ ) {
381 Node *m = _table[i];
382 if( !m || m == _sentinel ) continue;
383 if( m->_idx == (uint)idx ) return m;
384 }
385 return NULL;
386 }
387 #endif
388
389 #ifdef ASSERT
390 NodeHash::~NodeHash() {
391 // Unlock all nodes upon destruction of table.
392 if (_table != (Node**)badAddress) clear();
393 }
394
395 void NodeHash::operator=(const NodeHash& nh) {
396 // Unlock all nodes upon replacement of table.
397 if (&nh == this) return;
398 if (_table != (Node**)badAddress) clear();
399 memcpy((void*)this, (void*)&nh, sizeof(*this));
400 // Do not increment hash_lock counts again.
401 // Instead, be sure we never again use the source table.
402 ((NodeHash*)&nh)->_table = (Node**)badAddress;
403 }
404
405
406 #endif
407
408
409 //=============================================================================
410 //------------------------------PhaseRemoveUseless-----------------------------
411 // 1) Use a breadthfirst walk to collect useful nodes reachable from root.
412 PhaseRemoveUseless::PhaseRemoveUseless(PhaseGVN *gvn, Unique_Node_List *worklist, PhaseNumber phase_num) : Phase(phase_num),
413 _useful(Thread::current()->resource_area()) {
414
415 // Implementation requires 'UseLoopSafepoints == true' and an edge from root
416 // to each SafePointNode at a backward branch. Inserted in add_safepoint().
417 if( !UseLoopSafepoints || !OptoRemoveUseless ) return;
418
419 // Identify nodes that are reachable from below, useful.
420 C->identify_useful_nodes(_useful);
421 // Update dead node list
422 C->update_dead_node_list(_useful);
423
424 // Remove all useless nodes from PhaseValues' recorded types
425 // Must be done before disconnecting nodes to preserve hash-table-invariant
426 gvn->remove_useless_nodes(_useful.member_set());
427
428 // Remove all useless nodes from future worklist
429 worklist->remove_useless_nodes(_useful.member_set());
430
431 // Disconnect 'useless' nodes that are adjacent to useful nodes
432 C->remove_useless_nodes(_useful);
433 }
434
435 //=============================================================================
436 //------------------------------PhaseRenumberLive------------------------------
437 // First, remove useless nodes (equivalent to identifying live nodes).
438 // Then, renumber live nodes.
439 //
440 // The set of live nodes is returned by PhaseRemoveUseless in the _useful structure.
441 // If the number of live nodes is 'x' (where 'x' == _useful.size()), then the
442 // PhaseRenumberLive updates the node ID of each node (the _idx field) with a unique
443 // value in the range [0, x).
444 //
445 // At the end of the PhaseRenumberLive phase, the compiler's count of unique nodes is
446 // updated to 'x' and the list of dead nodes is reset (as there are no dead nodes).
447 //
448 // The PhaseRenumberLive phase updates two data structures with the new node IDs.
449 // (1) The worklist is used by the PhaseIterGVN phase to identify nodes that must be
450 // processed. A new worklist (with the updated node IDs) is returned in 'new_worklist'.
451 // (2) Type information (the field PhaseGVN::_types) maps type information to each
452 // node ID. The mapping is updated to use the new node IDs as well. Updated type
453 // information is returned in PhaseGVN::_types.
454 //
455 // The PhaseRenumberLive phase does not preserve the order of elements in the worklist.
456 //
457 // Other data structures used by the compiler are not updated. The hash table for value
458 // numbering (the field PhaseGVN::_table) is not updated because computing the hash
459 // values is not based on node IDs. The field PhaseGVN::_nodes is not updated either
460 // because it is empty wherever PhaseRenumberLive is used.
461 PhaseRenumberLive::PhaseRenumberLive(PhaseGVN* gvn,
462 Unique_Node_List* worklist, Unique_Node_List* new_worklist,
463 PhaseNumber phase_num) :
464 PhaseRemoveUseless(gvn, worklist, Remove_Useless_And_Renumber_Live),
465 _new_type_array(C->comp_arena()),
466 _old2new_map(C->unique(), C->unique(), -1),
467 _delayed(Thread::current()->resource_area()),
468 _is_pass_finished(false),
469 _live_node_count(C->live_nodes())
470 {
471 assert(RenumberLiveNodes, "RenumberLiveNodes must be set to true for node renumbering to take place");
472 assert(C->live_nodes() == _useful.size(), "the number of live nodes must match the number of useful nodes");
473 assert(gvn->nodes_size() == 0, "GVN must not contain any nodes at this point");
474 assert(_delayed.size() == 0, "should be empty");
475
476 uint worklist_size = worklist->size();
477
478 // Iterate over the set of live nodes.
479 for (uint current_idx = 0; current_idx < _useful.size(); current_idx++) {
480 Node* n = _useful.at(current_idx);
481
482 bool in_worklist = false;
483 if (worklist->member(n)) {
484 in_worklist = true;
485 }
486
487 const Type* type = gvn->type_or_null(n);
488 _new_type_array.map(current_idx, type);
489
490 assert(_old2new_map.at(n->_idx) == -1, "already seen");
491 _old2new_map.at_put(n->_idx, current_idx);
492
493 n->set_idx(current_idx); // Update node ID.
494
495 if (in_worklist) {
496 new_worklist->push(n);
497 }
498
499 if (update_embedded_ids(n) < 0) {
500 _delayed.push(n); // has embedded IDs; handle later
501 }
502 }
503
504 assert(worklist_size == new_worklist->size(), "the new worklist must have the same size as the original worklist");
505 assert(_live_node_count == _useful.size(), "all live nodes must be processed");
506
507 _is_pass_finished = true; // pass finished; safe to process delayed updates
508
509 while (_delayed.size() > 0) {
510 Node* n = _delayed.pop();
511 int no_of_updates = update_embedded_ids(n);
512 assert(no_of_updates > 0, "should be updated");
513 }
514
515 // Replace the compiler's type information with the updated type information.
516 gvn->replace_types(_new_type_array);
517
518 // Update the unique node count of the compilation to the number of currently live nodes.
519 C->set_unique(_live_node_count);
520
521 // Set the dead node count to 0 and reset dead node list.
522 C->reset_dead_node_list();
523 }
524
525 int PhaseRenumberLive::new_index(int old_idx) {
526 assert(_is_pass_finished, "not finished");
527 if (_old2new_map.at(old_idx) == -1) { // absent
528 // Allocate a placeholder to preserve uniqueness
529 _old2new_map.at_put(old_idx, _live_node_count);
530 _live_node_count++;
531 }
532 return _old2new_map.at(old_idx);
533 }
534
535 int PhaseRenumberLive::update_embedded_ids(Node* n) {
536 int no_of_updates = 0;
537 if (n->is_Phi()) {
538 PhiNode* phi = n->as_Phi();
539 if (phi->_inst_id != -1) {
540 if (!_is_pass_finished) {
541 return -1; // delay
542 }
543 int new_idx = new_index(phi->_inst_id);
544 assert(new_idx != -1, "");
545 phi->_inst_id = new_idx;
546 no_of_updates++;
547 }
548 if (phi->_inst_mem_id != -1) {
549 if (!_is_pass_finished) {
550 return -1; // delay
551 }
552 int new_idx = new_index(phi->_inst_mem_id);
553 assert(new_idx != -1, "");
554 phi->_inst_mem_id = new_idx;
555 no_of_updates++;
556 }
557 }
558
559 const Type* type = _new_type_array.fast_lookup(n->_idx);
560 if (type != NULL && type->isa_oopptr() && type->is_oopptr()->is_known_instance()) {
561 if (!_is_pass_finished) {
562 return -1; // delay
563 }
564 int old_idx = type->is_oopptr()->instance_id();
565 int new_idx = new_index(old_idx);
566 const Type* new_type = type->is_oopptr()->with_instance_id(new_idx);
567 _new_type_array.map(n->_idx, new_type);
568 no_of_updates++;
569 }
570
571 return no_of_updates;
572 }
573
574 //=============================================================================
575 //------------------------------PhaseTransform---------------------------------
576 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
577 _arena(Thread::current()->resource_area()),
578 _nodes(_arena),
579 _types(_arena)
580 {
581 init_con_caches();
582 #ifndef PRODUCT
583 clear_progress();
584 clear_transforms();
585 set_allow_progress(true);
586 #endif
587 // Force allocation for currently existing nodes
588 _types.map(C->unique(), NULL);
589 }
590
591 //------------------------------PhaseTransform---------------------------------
592 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
593 _arena(arena),
594 _nodes(arena),
595 _types(arena)
596 {
597 init_con_caches();
598 #ifndef PRODUCT
599 clear_progress();
600 clear_transforms();
601 set_allow_progress(true);
602 #endif
603 // Force allocation for currently existing nodes
604 _types.map(C->unique(), NULL);
605 }
606
607 //------------------------------PhaseTransform---------------------------------
608 // Initialize with previously generated type information
609 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
610 _arena(pt->_arena),
611 _nodes(pt->_nodes),
612 _types(pt->_types)
613 {
614 init_con_caches();
615 #ifndef PRODUCT
616 clear_progress();
617 clear_transforms();
618 set_allow_progress(true);
619 #endif
620 }
621
622 void PhaseTransform::init_con_caches() {
623 memset(_icons,0,sizeof(_icons));
624 memset(_lcons,0,sizeof(_lcons));
625 memset(_zcons,0,sizeof(_zcons));
626 }
627
628
629 //--------------------------------find_int_type--------------------------------
630 const TypeInt* PhaseTransform::find_int_type(Node* n) {
631 if (n == NULL) return NULL;
632 // Call type_or_null(n) to determine node's type since we might be in
633 // parse phase and call n->Value() may return wrong type.
634 // (For example, a phi node at the beginning of loop parsing is not ready.)
635 const Type* t = type_or_null(n);
636 if (t == NULL) return NULL;
637 return t->isa_int();
638 }
639
640
641 //-------------------------------find_long_type--------------------------------
642 const TypeLong* PhaseTransform::find_long_type(Node* n) {
643 if (n == NULL) return NULL;
644 // (See comment above on type_or_null.)
645 const Type* t = type_or_null(n);
646 if (t == NULL) return NULL;
647 return t->isa_long();
648 }
649
650
651 #ifndef PRODUCT
652 void PhaseTransform::dump_old2new_map() const {
653 _nodes.dump();
654 }
655
656 void PhaseTransform::dump_new( uint nidx ) const {
657 for( uint i=0; i<_nodes.Size(); i++ )
658 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
659 _nodes[i]->dump();
660 tty->cr();
661 tty->print_cr("Old index= %d",i);
662 return;
663 }
664 tty->print_cr("Node %d not found in the new indices", nidx);
665 }
666
667 //------------------------------dump_types-------------------------------------
668 void PhaseTransform::dump_types( ) const {
669 _types.dump();
670 }
671
672 //------------------------------dump_nodes_and_types---------------------------
673 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
674 VectorSet visited(Thread::current()->resource_area());
675 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
676 }
677
678 //------------------------------dump_nodes_and_types_recur---------------------
679 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
680 if( !n ) return;
681 if( depth == 0 ) return;
682 if( visited.test_set(n->_idx) ) return;
683 for( uint i=0; i<n->len(); i++ ) {
684 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
685 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
686 }
687 n->dump();
688 if (type_or_null(n) != NULL) {
689 tty->print(" "); type(n)->dump(); tty->cr();
690 }
691 }
692
693 #endif
694
695
696 //=============================================================================
697 //------------------------------PhaseValues------------------------------------
698 // Set minimum table size to "255"
699 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
700 NOT_PRODUCT( clear_new_values(); )
701 }
702
703 //------------------------------PhaseValues------------------------------------
704 // Set minimum table size to "255"
705 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
706 _table(&ptv->_table) {
707 NOT_PRODUCT( clear_new_values(); )
708 }
709
710 //------------------------------PhaseValues------------------------------------
711 // Used by +VerifyOpto. Clear out hash table but copy _types array.
712 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
713 _table(ptv->arena(),ptv->_table.size()) {
714 NOT_PRODUCT( clear_new_values(); )
715 }
716
717 //------------------------------~PhaseValues-----------------------------------
718 #ifndef PRODUCT
719 PhaseValues::~PhaseValues() {
720 _table.dump();
721
722 // Statistics for value progress and efficiency
723 if( PrintCompilation && Verbose && WizardMode ) {
724 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
725 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
726 if( made_transforms() != 0 ) {
727 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
728 } else {
729 tty->cr();
730 }
731 }
732 }
733 #endif
734
735 //------------------------------makecon----------------------------------------
736 ConNode* PhaseTransform::makecon(const Type *t) {
737 assert(t->singleton(), "must be a constant");
738 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
739 switch (t->base()) { // fast paths
740 case Type::Half:
741 case Type::Top: return (ConNode*) C->top();
742 case Type::Int: return intcon( t->is_int()->get_con() );
743 case Type::Long: return longcon( t->is_long()->get_con() );
744 default: break;
745 }
746 if (t->is_zero_type())
747 return zerocon(t->basic_type());
748 return uncached_makecon(t);
749 }
750
751 //--------------------------uncached_makecon-----------------------------------
752 // Make an idealized constant - one of ConINode, ConPNode, etc.
753 ConNode* PhaseValues::uncached_makecon(const Type *t) {
754 assert(t->singleton(), "must be a constant");
755 ConNode* x = ConNode::make(t);
756 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
757 if (k == NULL) {
758 set_type(x, t); // Missed, provide type mapping
759 GrowableArray<Node_Notes*>* nna = C->node_note_array();
760 if (nna != NULL) {
761 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
762 loc->clear(); // do not put debug info on constants
763 }
764 } else {
765 x->destruct(); // Hit, destroy duplicate constant
766 x = k; // use existing constant
767 }
768 return x;
769 }
770
771 //------------------------------intcon-----------------------------------------
772 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
773 ConINode* PhaseTransform::intcon(jint i) {
774 // Small integer? Check cache! Check that cached node is not dead
775 if (i >= _icon_min && i <= _icon_max) {
776 ConINode* icon = _icons[i-_icon_min];
777 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
778 return icon;
779 }
780 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
781 assert(icon->is_Con(), "");
782 if (i >= _icon_min && i <= _icon_max)
783 _icons[i-_icon_min] = icon; // Cache small integers
784 return icon;
785 }
786
787 //------------------------------longcon----------------------------------------
788 // Fast long constant.
789 ConLNode* PhaseTransform::longcon(jlong l) {
790 // Small integer? Check cache! Check that cached node is not dead
791 if (l >= _lcon_min && l <= _lcon_max) {
792 ConLNode* lcon = _lcons[l-_lcon_min];
793 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
794 return lcon;
795 }
796 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
797 assert(lcon->is_Con(), "");
798 if (l >= _lcon_min && l <= _lcon_max)
799 _lcons[l-_lcon_min] = lcon; // Cache small integers
800 return lcon;
801 }
802
803 //------------------------------zerocon-----------------------------------------
804 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
805 ConNode* PhaseTransform::zerocon(BasicType bt) {
806 assert((uint)bt <= _zcon_max, "domain check");
807 ConNode* zcon = _zcons[bt];
808 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
809 return zcon;
810 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
811 _zcons[bt] = zcon;
812 return zcon;
813 }
814
815
816
817 //=============================================================================
818 Node* PhaseGVN::apply_ideal(Node* k, bool can_reshape) {
819 Node* i = BarrierSet::barrier_set()->barrier_set_c2()->ideal_node(this, k, can_reshape);
820 if (i == NULL) {
821 i = k->Ideal(this, can_reshape);
822 }
823 return i;
824 }
825
826 Node* PhaseGVN::apply_identity(Node* k) {
827 Node* i = BarrierSet::barrier_set()->barrier_set_c2()->identity_node(this, k);
828 if (i == k) {
829 i = k->Identity(this);
830 }
831 return i;
832 }
833
834 //------------------------------transform--------------------------------------
835 // Return a node which computes the same function as this node, but in a
836 // faster or cheaper fashion.
837 Node *PhaseGVN::transform( Node *n ) {
838 return transform_no_reclaim(n);
839 }
840
841 //------------------------------transform--------------------------------------
842 // Return a node which computes the same function as this node, but
843 // in a faster or cheaper fashion.
844 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
845 NOT_PRODUCT( set_transforms(); )
846
847 // Apply the Ideal call in a loop until it no longer applies
848 Node *k = n;
849 NOT_PRODUCT( uint loop_count = 0; )
850 while( 1 ) {
851 Node *i = apply_ideal(k, /*can_reshape=*/false);
852 if( !i ) break;
853 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
854 k = i;
855 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
856 }
857 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
858
859
860 // If brand new node, make space in type array.
861 ensure_type_or_null(k);
862
863 // Since I just called 'Value' to compute the set of run-time values
864 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
865 // cache Value. Later requests for the local phase->type of this Node can
866 // use the cached Value instead of suffering with 'bottom_type'.
867 const Type *t = k->Value(this); // Get runtime Value set
868 assert(t != NULL, "value sanity");
869 if (type_or_null(k) != t) {
870 #ifndef PRODUCT
871 // Do not count initial visit to node as a transformation
872 if (type_or_null(k) == NULL) {
873 inc_new_values();
874 set_progress();
875 }
876 #endif
877 set_type(k, t);
878 // If k is a TypeNode, capture any more-precise type permanently into Node
879 k->raise_bottom_type(t);
880 }
881
882 if( t->singleton() && !k->is_Con() ) {
883 NOT_PRODUCT( set_progress(); )
884 return makecon(t); // Turn into a constant
885 }
886
887 // Now check for Identities
888 Node *i = apply_identity(k); // Look for a nearby replacement
889 if( i != k ) { // Found? Return replacement!
890 NOT_PRODUCT( set_progress(); )
891 return i;
892 }
893
894 // Global Value Numbering
895 i = hash_find_insert(k); // Insert if new
896 if( i && (i != k) ) {
897 // Return the pre-existing node
898 NOT_PRODUCT( set_progress(); )
899 return i;
900 }
901
902 // Return Idealized original
903 return k;
904 }
905
906 bool PhaseGVN::is_dominator_helper(Node *d, Node *n, bool linear_only) {
907 if (d->is_top() || n->is_top()) {
908 return false;
909 }
910 assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes");
911 int i = 0;
912 while (d != n) {
913 n = IfNode::up_one_dom(n, linear_only);
914 i++;
915 if (n == NULL || i >= 10) {
916 return false;
917 }
918 }
919 return true;
920 }
921
922 #ifdef ASSERT
923 //------------------------------dead_loop_check--------------------------------
924 // Check for a simple dead loop when a data node references itself directly
925 // or through an other data node excluding cons and phis.
926 void PhaseGVN::dead_loop_check( Node *n ) {
927 // Phi may reference itself in a loop
928 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
929 // Do 2 levels check and only data inputs.
930 bool no_dead_loop = true;
931 uint cnt = n->req();
932 for (uint i = 1; i < cnt && no_dead_loop; i++) {
933 Node *in = n->in(i);
934 if (in == n) {
935 no_dead_loop = false;
936 } else if (in != NULL && !in->is_dead_loop_safe()) {
937 uint icnt = in->req();
938 for (uint j = 1; j < icnt && no_dead_loop; j++) {
939 if (in->in(j) == n || in->in(j) == in)
940 no_dead_loop = false;
941 }
942 }
943 }
944 if (!no_dead_loop) n->dump(3);
945 assert(no_dead_loop, "dead loop detected");
946 }
947 }
948 #endif
949
950 //=============================================================================
951 //------------------------------PhaseIterGVN-----------------------------------
952 // Initialize hash table to fresh and clean for +VerifyOpto
953 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy),
954 _delay_transform(false),
955 _stack(C->live_nodes() >> 1),
956 _worklist( ) {
957 }
958
959 //------------------------------PhaseIterGVN-----------------------------------
960 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
961 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
962 _delay_transform(igvn->_delay_transform),
963 _stack( igvn->_stack ),
964 _worklist( igvn->_worklist )
965 {
966 }
967
968 //------------------------------PhaseIterGVN-----------------------------------
969 // Initialize with previous PhaseGVN info from Parser
970 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
971 _delay_transform(false),
972 // TODO: Before incremental inlining it was allocated only once and it was fine. Now that
973 // the constructor is used in incremental inlining, this consumes too much memory:
974 // _stack(C->live_nodes() >> 1),
975 // So, as a band-aid, we replace this by:
976 _stack(C->comp_arena(), 32),
977 _worklist(*C->for_igvn())
978 {
979 uint max;
980
981 // Dead nodes in the hash table inherited from GVN were not treated as
982 // roots during def-use info creation; hence they represent an invisible
983 // use. Clear them out.
984 max = _table.size();
985 for( uint i = 0; i < max; ++i ) {
986 Node *n = _table.at(i);
987 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
988 if( n->is_top() ) continue;
989 assert( false, "Parse::remove_useless_nodes missed this node");
990 hash_delete(n);
991 }
992 }
993
994 // Any Phis or Regions on the worklist probably had uses that could not
995 // make more progress because the uses were made while the Phis and Regions
996 // were in half-built states. Put all uses of Phis and Regions on worklist.
997 max = _worklist.size();
998 for( uint j = 0; j < max; j++ ) {
999 Node *n = _worklist.at(j);
1000 uint uop = n->Opcode();
1001 if( uop == Op_Phi || uop == Op_Region ||
1002 n->is_Type() ||
1003 n->is_Mem() )
1004 add_users_to_worklist(n);
1005 }
1006
1007 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1008 bs->add_users_to_worklist(&_worklist);
1009 }
1010
1011 /**
1012 * Initialize worklist for each node.
1013 */
1014 void PhaseIterGVN::init_worklist(Node* first) {
1015 Unique_Node_List to_process;
1016 to_process.push(first);
1017
1018 while (to_process.size() > 0) {
1019 Node* n = to_process.pop();
1020 if (!_worklist.member(n)) {
1021 _worklist.push(n);
1022
1023 uint cnt = n->req();
1024 for(uint i = 0; i < cnt; i++) {
1025 Node* m = n->in(i);
1026 if (m != NULL) {
1027 to_process.push(m);
1028 }
1029 }
1030 }
1031 }
1032 }
1033
1034 #ifndef PRODUCT
1035 void PhaseIterGVN::verify_step(Node* n) {
1036 if (VerifyIterativeGVN) {
1037 _verify_window[_verify_counter % _verify_window_size] = n;
1038 ++_verify_counter;
1039 ResourceMark rm;
1040 ResourceArea* area = Thread::current()->resource_area();
1041 VectorSet old_space(area), new_space(area);
1042 if (C->unique() < 1000 ||
1043 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
1044 ++_verify_full_passes;
1045 Node::verify_recur(C->root(), -1, old_space, new_space);
1046 }
1047 const int verify_depth = 4;
1048 for ( int i = 0; i < _verify_window_size; i++ ) {
1049 Node* n = _verify_window[i];
1050 if ( n == NULL ) continue;
1051 if( n->in(0) == NodeSentinel ) { // xform_idom
1052 _verify_window[i] = n->in(1);
1053 --i; continue;
1054 }
1055 // Typical fanout is 1-2, so this call visits about 6 nodes.
1056 Node::verify_recur(n, verify_depth, old_space, new_space);
1057 }
1058 }
1059 }
1060
1061 void PhaseIterGVN::trace_PhaseIterGVN(Node* n, Node* nn, const Type* oldtype) {
1062 if (TraceIterativeGVN) {
1063 uint wlsize = _worklist.size();
1064 const Type* newtype = type_or_null(n);
1065 if (nn != n) {
1066 // print old node
1067 tty->print("< ");
1068 if (oldtype != newtype && oldtype != NULL) {
1069 oldtype->dump();
1070 }
1071 do { tty->print("\t"); } while (tty->position() < 16);
1072 tty->print("<");
1073 n->dump();
1074 }
1075 if (oldtype != newtype || nn != n) {
1076 // print new node and/or new type
1077 if (oldtype == NULL) {
1078 tty->print("* ");
1079 } else if (nn != n) {
1080 tty->print("> ");
1081 } else {
1082 tty->print("= ");
1083 }
1084 if (newtype == NULL) {
1085 tty->print("null");
1086 } else {
1087 newtype->dump();
1088 }
1089 do { tty->print("\t"); } while (tty->position() < 16);
1090 nn->dump();
1091 }
1092 if (Verbose && wlsize < _worklist.size()) {
1093 tty->print(" Push {");
1094 while (wlsize != _worklist.size()) {
1095 Node* pushed = _worklist.at(wlsize++);
1096 tty->print(" %d", pushed->_idx);
1097 }
1098 tty->print_cr(" }");
1099 }
1100 if (nn != n) {
1101 // ignore n, it might be subsumed
1102 verify_step((Node*) NULL);
1103 }
1104 }
1105 }
1106
1107 void PhaseIterGVN::init_verifyPhaseIterGVN() {
1108 _verify_counter = 0;
1109 _verify_full_passes = 0;
1110 for (int i = 0; i < _verify_window_size; i++) {
1111 _verify_window[i] = NULL;
1112 }
1113 #ifdef ASSERT
1114 // Verify that all modified nodes are on _worklist
1115 Unique_Node_List* modified_list = C->modified_nodes();
1116 while (modified_list != NULL && modified_list->size()) {
1117 Node* n = modified_list->pop();
1118 if (n->outcnt() != 0 && !n->is_Con() && !_worklist.member(n)) {
1119 n->dump();
1120 assert(false, "modified node is not on IGVN._worklist");
1121 }
1122 }
1123 #endif
1124 }
1125
1126 void PhaseIterGVN::verify_PhaseIterGVN() {
1127 #ifdef ASSERT
1128 // Verify nodes with changed inputs.
1129 Unique_Node_List* modified_list = C->modified_nodes();
1130 while (modified_list != NULL && modified_list->size()) {
1131 Node* n = modified_list->pop();
1132 if (n->outcnt() != 0 && !n->is_Con()) { // skip dead and Con nodes
1133 n->dump();
1134 assert(false, "modified node was not processed by IGVN.transform_old()");
1135 }
1136 }
1137 #endif
1138
1139 C->verify_graph_edges();
1140 if( VerifyOpto && allow_progress() ) {
1141 // Must turn off allow_progress to enable assert and break recursion
1142 C->root()->verify();
1143 { // Check if any progress was missed using IterGVN
1144 // Def-Use info enables transformations not attempted in wash-pass
1145 // e.g. Region/Phi cleanup, ...
1146 // Null-check elision -- may not have reached fixpoint
1147 // do not propagate to dominated nodes
1148 ResourceMark rm;
1149 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
1150 // Fill worklist completely
1151 igvn2.init_worklist(C->root());
1152
1153 igvn2.set_allow_progress(false);
1154 igvn2.optimize();
1155 igvn2.set_allow_progress(true);
1156 }
1157 }
1158 if (VerifyIterativeGVN && PrintOpto) {
1159 if (_verify_counter == _verify_full_passes) {
1160 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
1161 (int) _verify_full_passes);
1162 } else {
1163 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
1164 (int) _verify_counter, (int) _verify_full_passes);
1165 }
1166 }
1167
1168 #ifdef ASSERT
1169 while (modified_list->size()) {
1170 Node* n = modified_list->pop();
1171 n->dump();
1172 assert(false, "VerifyIterativeGVN: new modified node was added");
1173 }
1174 #endif
1175 }
1176 #endif /* PRODUCT */
1177
1178 #ifdef ASSERT
1179 /**
1180 * Dumps information that can help to debug the problem. A debug
1181 * build fails with an assert.
1182 */
1183 void PhaseIterGVN::dump_infinite_loop_info(Node* n) {
1184 n->dump(4);
1185 _worklist.dump();
1186 assert(false, "infinite loop in PhaseIterGVN::optimize");
1187 }
1188
1189 /**
1190 * Prints out information about IGVN if the 'verbose' option is used.
1191 */
1192 void PhaseIterGVN::trace_PhaseIterGVN_verbose(Node* n, int num_processed) {
1193 if (TraceIterativeGVN && Verbose) {
1194 tty->print(" Pop ");
1195 n->dump();
1196 if ((num_processed % 100) == 0) {
1197 _worklist.print_set();
1198 }
1199 }
1200 }
1201 #endif /* ASSERT */
1202
1203 void PhaseIterGVN::optimize() {
1204 DEBUG_ONLY(uint num_processed = 0;)
1205 NOT_PRODUCT(init_verifyPhaseIterGVN();)
1206
1207 uint loop_count = 0;
1208 // Pull from worklist and transform the node. If the node has changed,
1209 // update edge info and put uses on worklist.
1210 while(_worklist.size()) {
1211 if (C->check_node_count(NodeLimitFudgeFactor * 2, "Out of nodes")) {
1212 return;
1213 }
1214 Node* n = _worklist.pop();
1215 if (++loop_count >= K * C->live_nodes()) {
1216 DEBUG_ONLY(dump_infinite_loop_info(n);)
1217 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
1218 return;
1219 }
1220 DEBUG_ONLY(trace_PhaseIterGVN_verbose(n, num_processed++);)
1221 if (n->outcnt() != 0) {
1222 NOT_PRODUCT(const Type* oldtype = type_or_null(n));
1223 // Do the transformation
1224 Node* nn = transform_old(n);
1225 NOT_PRODUCT(trace_PhaseIterGVN(n, nn, oldtype);)
1226 } else if (!n->is_top()) {
1227 remove_dead_node(n);
1228 }
1229 }
1230 NOT_PRODUCT(verify_PhaseIterGVN();)
1231 }
1232
1233
1234 /**
1235 * Register a new node with the optimizer. Update the types array, the def-use
1236 * info. Put on worklist.
1237 */
1238 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1239 set_type_bottom(n);
1240 _worklist.push(n);
1241 if (orig != NULL) C->copy_node_notes_to(n, orig);
1242 return n;
1243 }
1244
1245 //------------------------------transform--------------------------------------
1246 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1247 Node *PhaseIterGVN::transform( Node *n ) {
1248 if (_delay_transform) {
1249 // Register the node but don't optimize for now
1250 register_new_node_with_optimizer(n);
1251 return n;
1252 }
1253
1254 // If brand new node, make space in type array, and give it a type.
1255 ensure_type_or_null(n);
1256 if (type_or_null(n) == NULL) {
1257 set_type_bottom(n);
1258 }
1259
1260 return transform_old(n);
1261 }
1262
1263 Node *PhaseIterGVN::transform_old(Node* n) {
1264 DEBUG_ONLY(uint loop_count = 0;);
1265 NOT_PRODUCT(set_transforms());
1266
1267 // Remove 'n' from hash table in case it gets modified
1268 _table.hash_delete(n);
1269 if (VerifyIterativeGVN) {
1270 assert(!_table.find_index(n->_idx), "found duplicate entry in table");
1271 }
1272
1273 // Apply the Ideal call in a loop until it no longer applies
1274 Node* k = n;
1275 DEBUG_ONLY(dead_loop_check(k);)
1276 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1277 C->remove_modified_node(k);
1278 Node* i = apply_ideal(k, /*can_reshape=*/true);
1279 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1280 #ifndef PRODUCT
1281 verify_step(k);
1282 if (i && VerifyOpto ) {
1283 if (!allow_progress()) {
1284 if (i->is_Add() && (i->outcnt() == 1)) {
1285 // Switched input to left side because this is the only use
1286 } else if (i->is_If() && (i->in(0) == NULL)) {
1287 // This IF is dead because it is dominated by an equivalent IF When
1288 // dominating if changed, info is not propagated sparsely to 'this'
1289 // Propagating this info further will spuriously identify other
1290 // progress.
1291 return i;
1292 } else
1293 set_progress();
1294 } else {
1295 set_progress();
1296 }
1297 }
1298 #endif
1299
1300 while (i != NULL) {
1301 #ifdef ASSERT
1302 if (loop_count >= K) {
1303 dump_infinite_loop_info(i);
1304 }
1305 loop_count++;
1306 #endif
1307 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1308 // Made a change; put users of original Node on worklist
1309 add_users_to_worklist(k);
1310 // Replacing root of transform tree?
1311 if (k != i) {
1312 // Make users of old Node now use new.
1313 subsume_node(k, i);
1314 k = i;
1315 }
1316 DEBUG_ONLY(dead_loop_check(k);)
1317 // Try idealizing again
1318 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1319 C->remove_modified_node(k);
1320 i = apply_ideal(k, /*can_reshape=*/true);
1321 assert(i != k || is_new || (i->outcnt() > 0), "don't return dead nodes");
1322 #ifndef PRODUCT
1323 verify_step(k);
1324 if (i && VerifyOpto) {
1325 set_progress();
1326 }
1327 #endif
1328 }
1329
1330 // If brand new node, make space in type array.
1331 ensure_type_or_null(k);
1332
1333 // See what kind of values 'k' takes on at runtime
1334 const Type* t = k->Value(this);
1335 assert(t != NULL, "value sanity");
1336
1337 // Since I just called 'Value' to compute the set of run-time values
1338 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1339 // cache Value. Later requests for the local phase->type of this Node can
1340 // use the cached Value instead of suffering with 'bottom_type'.
1341 if (type_or_null(k) != t) {
1342 #ifndef PRODUCT
1343 inc_new_values();
1344 set_progress();
1345 #endif
1346 set_type(k, t);
1347 // If k is a TypeNode, capture any more-precise type permanently into Node
1348 k->raise_bottom_type(t);
1349 // Move users of node to worklist
1350 add_users_to_worklist(k);
1351 }
1352 // If 'k' computes a constant, replace it with a constant
1353 if (t->singleton() && !k->is_Con()) {
1354 NOT_PRODUCT(set_progress();)
1355 Node* con = makecon(t); // Make a constant
1356 add_users_to_worklist(k);
1357 subsume_node(k, con); // Everybody using k now uses con
1358 return con;
1359 }
1360
1361 // Now check for Identities
1362 i = apply_identity(k); // Look for a nearby replacement
1363 if (i != k) { // Found? Return replacement!
1364 NOT_PRODUCT(set_progress();)
1365 add_users_to_worklist(k);
1366 subsume_node(k, i); // Everybody using k now uses i
1367 return i;
1368 }
1369
1370 // Global Value Numbering
1371 i = hash_find_insert(k); // Check for pre-existing node
1372 if (i && (i != k)) {
1373 // Return the pre-existing node if it isn't dead
1374 NOT_PRODUCT(set_progress();)
1375 add_users_to_worklist(k);
1376 subsume_node(k, i); // Everybody using k now uses i
1377 return i;
1378 }
1379
1380 // Return Idealized original
1381 return k;
1382 }
1383
1384 //---------------------------------saturate------------------------------------
1385 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1386 const Type* limit_type) const {
1387 return new_type->narrow(old_type);
1388 }
1389
1390 //------------------------------remove_globally_dead_node----------------------
1391 // Kill a globally dead Node. All uses are also globally dead and are
1392 // aggressively trimmed.
1393 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1394 enum DeleteProgress {
1395 PROCESS_INPUTS,
1396 PROCESS_OUTPUTS
1397 };
1398 assert(_stack.is_empty(), "not empty");
1399 _stack.push(dead, PROCESS_INPUTS);
1400
1401 while (_stack.is_nonempty()) {
1402 dead = _stack.node();
1403 if (dead->Opcode() == Op_SafePoint) {
1404 dead->as_SafePoint()->disconnect_from_root(this);
1405 }
1406 uint progress_state = _stack.index();
1407 assert(dead != C->root(), "killing root, eh?");
1408 assert(!dead->is_top(), "add check for top when pushing");
1409 NOT_PRODUCT( set_progress(); )
1410 if (progress_state == PROCESS_INPUTS) {
1411 // After following inputs, continue to outputs
1412 _stack.set_index(PROCESS_OUTPUTS);
1413 if (!dead->is_Con()) { // Don't kill cons but uses
1414 bool recurse = false;
1415 // Remove from hash table
1416 _table.hash_delete( dead );
1417 // Smash all inputs to 'dead', isolating him completely
1418 for (uint i = 0; i < dead->req(); i++) {
1419 Node *in = dead->in(i);
1420 if (in != NULL && in != C->top()) { // Points to something?
1421 int nrep = dead->replace_edge(in, NULL); // Kill edges
1422 assert((nrep > 0), "sanity");
1423 if (in->outcnt() == 0) { // Made input go dead?
1424 _stack.push(in, PROCESS_INPUTS); // Recursively remove
1425 recurse = true;
1426 } else if (in->outcnt() == 1 &&
1427 in->has_special_unique_user()) {
1428 _worklist.push(in->unique_out());
1429 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1430 if (in->Opcode() == Op_Region) {
1431 _worklist.push(in);
1432 } else if (in->is_Store()) {
1433 DUIterator_Fast imax, i = in->fast_outs(imax);
1434 _worklist.push(in->fast_out(i));
1435 i++;
1436 if (in->outcnt() == 2) {
1437 _worklist.push(in->fast_out(i));
1438 i++;
1439 }
1440 assert(!(i < imax), "sanity");
1441 }
1442 } else {
1443 BarrierSet::barrier_set()->barrier_set_c2()->enqueue_useful_gc_barrier(this, in);
1444 }
1445 if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory &&
1446 in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) {
1447 // A Load that directly follows an InitializeNode is
1448 // going away. The Stores that follow are candidates
1449 // again to be captured by the InitializeNode.
1450 for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) {
1451 Node *n = in->fast_out(j);
1452 if (n->is_Store()) {
1453 _worklist.push(n);
1454 }
1455 }
1456 }
1457 } // if (in != NULL && in != C->top())
1458 } // for (uint i = 0; i < dead->req(); i++)
1459 if (recurse) {
1460 continue;
1461 }
1462 } // if (!dead->is_Con())
1463 } // if (progress_state == PROCESS_INPUTS)
1464
1465 // Aggressively kill globally dead uses
1466 // (Rather than pushing all the outs at once, we push one at a time,
1467 // plus the parent to resume later, because of the indefinite number
1468 // of edge deletions per loop trip.)
1469 if (dead->outcnt() > 0) {
1470 // Recursively remove output edges
1471 _stack.push(dead->raw_out(0), PROCESS_INPUTS);
1472 } else {
1473 // Finished disconnecting all input and output edges.
1474 _stack.pop();
1475 // Remove dead node from iterative worklist
1476 _worklist.remove(dead);
1477 C->remove_modified_node(dead);
1478 // Constant node that has no out-edges and has only one in-edge from
1479 // root is usually dead. However, sometimes reshaping walk makes
1480 // it reachable by adding use edges. So, we will NOT count Con nodes
1481 // as dead to be conservative about the dead node count at any
1482 // given time.
1483 if (!dead->is_Con()) {
1484 C->record_dead_node(dead->_idx);
1485 }
1486 if (dead->is_macro()) {
1487 C->remove_macro_node(dead);
1488 }
1489 if (dead->is_expensive()) {
1490 C->remove_expensive_node(dead);
1491 }
1492 CastIINode* cast = dead->isa_CastII();
1493 if (cast != NULL && cast->has_range_check()) {
1494 C->remove_range_check_cast(cast);
1495 }
1496 if (dead->Opcode() == Op_Opaque4) {
1497 C->remove_opaque4_node(dead);
1498 }
1499 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1500 bs->unregister_potential_barrier_node(dead);
1501 }
1502 } // while (_stack.is_nonempty())
1503 }
1504
1505 //------------------------------subsume_node-----------------------------------
1506 // Remove users from node 'old' and add them to node 'nn'.
1507 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1508 if (old->Opcode() == Op_SafePoint) {
1509 old->as_SafePoint()->disconnect_from_root(this);
1510 }
1511 assert( old != hash_find(old), "should already been removed" );
1512 assert( old != C->top(), "cannot subsume top node");
1513 // Copy debug or profile information to the new version:
1514 C->copy_node_notes_to(nn, old);
1515 // Move users of node 'old' to node 'nn'
1516 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1517 Node* use = old->last_out(i); // for each use...
1518 // use might need re-hashing (but it won't if it's a new node)
1519 rehash_node_delayed(use);
1520 // Update use-def info as well
1521 // We remove all occurrences of old within use->in,
1522 // so as to avoid rehashing any node more than once.
1523 // The hash table probe swamps any outer loop overhead.
1524 uint num_edges = 0;
1525 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1526 if (use->in(j) == old) {
1527 use->set_req(j, nn);
1528 ++num_edges;
1529 }
1530 }
1531 i -= num_edges; // we deleted 1 or more copies of this edge
1532 }
1533
1534 // Search for instance field data PhiNodes in the same region pointing to the old
1535 // memory PhiNode and update their instance memory ids to point to the new node.
1536 if (old->is_Phi() && old->as_Phi()->type()->has_memory() && old->in(0) != NULL) {
1537 Node* region = old->in(0);
1538 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1539 PhiNode* phi = region->fast_out(i)->isa_Phi();
1540 if (phi != NULL && phi->inst_mem_id() == (int)old->_idx) {
1541 phi->set_inst_mem_id((int)nn->_idx);
1542 }
1543 }
1544 }
1545
1546 // Smash all inputs to 'old', isolating him completely
1547 Node *temp = new Node(1);
1548 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1549 remove_dead_node( old );
1550 temp->del_req(0); // Yank bogus edge
1551 #ifndef PRODUCT
1552 if( VerifyIterativeGVN ) {
1553 for ( int i = 0; i < _verify_window_size; i++ ) {
1554 if ( _verify_window[i] == old )
1555 _verify_window[i] = nn;
1556 }
1557 }
1558 #endif
1559 _worklist.remove(temp); // this can be necessary
1560 temp->destruct(); // reuse the _idx of this little guy
1561 }
1562
1563 //------------------------------add_users_to_worklist--------------------------
1564 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1565 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1566 _worklist.push(n->fast_out(i)); // Push on worklist
1567 }
1568 }
1569
1570 // Return counted loop Phi if as a counted loop exit condition, cmp
1571 // compares the the induction variable with n
1572 static PhiNode* countedloop_phi_from_cmp(CmpINode* cmp, Node* n) {
1573 for (DUIterator_Fast imax, i = cmp->fast_outs(imax); i < imax; i++) {
1574 Node* bol = cmp->fast_out(i);
1575 for (DUIterator_Fast i2max, i2 = bol->fast_outs(i2max); i2 < i2max; i2++) {
1576 Node* iff = bol->fast_out(i2);
1577 if (iff->is_CountedLoopEnd()) {
1578 CountedLoopEndNode* cle = iff->as_CountedLoopEnd();
1579 if (cle->limit() == n) {
1580 PhiNode* phi = cle->phi();
1581 if (phi != NULL) {
1582 return phi;
1583 }
1584 }
1585 }
1586 }
1587 }
1588 return NULL;
1589 }
1590
1591 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1592 add_users_to_worklist0(n);
1593
1594 // Move users of node to worklist
1595 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1596 Node* use = n->fast_out(i); // Get use
1597
1598 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1599 use->is_Store() ) // Enable store/load same address
1600 add_users_to_worklist0(use);
1601
1602 // If we changed the receiver type to a call, we need to revisit
1603 // the Catch following the call. It's looking for a non-NULL
1604 // receiver to know when to enable the regular fall-through path
1605 // in addition to the NullPtrException path.
1606 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1607 Node* p = use->as_CallDynamicJava()->proj_out_or_null(TypeFunc::Control);
1608 if (p != NULL) {
1609 add_users_to_worklist0(p);
1610 }
1611 }
1612
1613 uint use_op = use->Opcode();
1614 if(use->is_Cmp()) { // Enable CMP/BOOL optimization
1615 add_users_to_worklist(use); // Put Bool on worklist
1616 if (use->outcnt() > 0) {
1617 Node* bol = use->raw_out(0);
1618 if (bol->outcnt() > 0) {
1619 Node* iff = bol->raw_out(0);
1620 if (iff->outcnt() == 2) {
1621 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1622 // phi merging either 0 or 1 onto the worklist
1623 Node* ifproj0 = iff->raw_out(0);
1624 Node* ifproj1 = iff->raw_out(1);
1625 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1626 Node* region0 = ifproj0->raw_out(0);
1627 Node* region1 = ifproj1->raw_out(0);
1628 if( region0 == region1 )
1629 add_users_to_worklist0(region0);
1630 }
1631 }
1632 }
1633 }
1634 if (use_op == Op_CmpI) {
1635 Node* phi = countedloop_phi_from_cmp((CmpINode*)use, n);
1636 if (phi != NULL) {
1637 // If an opaque node feeds into the limit condition of a
1638 // CountedLoop, we need to process the Phi node for the
1639 // induction variable when the opaque node is removed:
1640 // the range of values taken by the Phi is now known and
1641 // so its type is also known.
1642 _worklist.push(phi);
1643 }
1644 Node* in1 = use->in(1);
1645 for (uint i = 0; i < in1->outcnt(); i++) {
1646 if (in1->raw_out(i)->Opcode() == Op_CastII) {
1647 Node* castii = in1->raw_out(i);
1648 if (castii->in(0) != NULL && castii->in(0)->in(0) != NULL && castii->in(0)->in(0)->is_If()) {
1649 Node* ifnode = castii->in(0)->in(0);
1650 if (ifnode->in(1) != NULL && ifnode->in(1)->is_Bool() && ifnode->in(1)->in(1) == use) {
1651 // Reprocess a CastII node that may depend on an
1652 // opaque node value when the opaque node is
1653 // removed. In case it carries a dependency we can do
1654 // a better job of computing its type.
1655 _worklist.push(castii);
1656 }
1657 }
1658 }
1659 }
1660 }
1661 }
1662
1663 // If changed Cast input, check Phi users for simple cycles
1664 if (use->is_ConstraintCast()) {
1665 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1666 Node* u = use->fast_out(i2);
1667 if (u->is_Phi())
1668 _worklist.push(u);
1669 }
1670 }
1671 // If changed LShift inputs, check RShift users for useless sign-ext
1672 if( use_op == Op_LShiftI ) {
1673 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1674 Node* u = use->fast_out(i2);
1675 if (u->Opcode() == Op_RShiftI)
1676 _worklist.push(u);
1677 }
1678 }
1679 // If changed AddI/SubI inputs, check CmpU for range check optimization.
1680 if (use_op == Op_AddI || use_op == Op_SubI) {
1681 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1682 Node* u = use->fast_out(i2);
1683 if (u->is_Cmp() && (u->Opcode() == Op_CmpU)) {
1684 _worklist.push(u);
1685 }
1686 }
1687 }
1688 // If changed AddP inputs, check Stores for loop invariant
1689 if( use_op == Op_AddP ) {
1690 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1691 Node* u = use->fast_out(i2);
1692 if (u->is_Mem())
1693 _worklist.push(u);
1694 }
1695 }
1696 // If changed initialization activity, check dependent Stores
1697 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1698 InitializeNode* init = use->as_Allocate()->initialization();
1699 if (init != NULL) {
1700 Node* imem = init->proj_out_or_null(TypeFunc::Memory);
1701 if (imem != NULL) add_users_to_worklist0(imem);
1702 }
1703 }
1704 if (use_op == Op_Initialize) {
1705 Node* imem = use->as_Initialize()->proj_out_or_null(TypeFunc::Memory);
1706 if (imem != NULL) add_users_to_worklist0(imem);
1707 }
1708 // Loading the java mirror from a Klass requires two loads and the type
1709 // of the mirror load depends on the type of 'n'. See LoadNode::Value().
1710 // LoadBarrier?(LoadP(LoadP(AddP(foo:Klass, #java_mirror))))
1711 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1712 bool has_load_barriers = bs->has_load_barriers();
1713
1714 if (use_op == Op_LoadP && use->bottom_type()->isa_rawptr()) {
1715 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1716 Node* u = use->fast_out(i2);
1717 const Type* ut = u->bottom_type();
1718 if (u->Opcode() == Op_LoadP && ut->isa_instptr()) {
1719 if (has_load_barriers) {
1720 // Search for load barriers behind the load
1721 for (DUIterator_Fast i3max, i3 = u->fast_outs(i3max); i3 < i3max; i3++) {
1722 Node* b = u->fast_out(i3);
1723 if (bs->is_gc_barrier_node(b)) {
1724 _worklist.push(b);
1725 }
1726 }
1727 }
1728 _worklist.push(u);
1729 }
1730 }
1731 }
1732
1733 BarrierSet::barrier_set()->barrier_set_c2()->igvn_add_users_to_worklist(this, use);
1734 }
1735 }
1736
1737 /**
1738 * Remove the speculative part of all types that we know of
1739 */
1740 void PhaseIterGVN::remove_speculative_types() {
1741 assert(UseTypeSpeculation, "speculation is off");
1742 for (uint i = 0; i < _types.Size(); i++) {
1743 const Type* t = _types.fast_lookup(i);
1744 if (t != NULL) {
1745 _types.map(i, t->remove_speculative());
1746 }
1747 }
1748 _table.check_no_speculative_types();
1749 }
1750
1751 //=============================================================================
1752 #ifndef PRODUCT
1753 uint PhaseCCP::_total_invokes = 0;
1754 uint PhaseCCP::_total_constants = 0;
1755 #endif
1756 //------------------------------PhaseCCP---------------------------------------
1757 // Conditional Constant Propagation, ala Wegman & Zadeck
1758 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1759 NOT_PRODUCT( clear_constants(); )
1760 assert( _worklist.size() == 0, "" );
1761 // Clear out _nodes from IterGVN. Must be clear to transform call.
1762 _nodes.clear(); // Clear out from IterGVN
1763 analyze();
1764 }
1765
1766 #ifndef PRODUCT
1767 //------------------------------~PhaseCCP--------------------------------------
1768 PhaseCCP::~PhaseCCP() {
1769 inc_invokes();
1770 _total_constants += count_constants();
1771 }
1772 #endif
1773
1774
1775 #ifdef ASSERT
1776 static bool ccp_type_widens(const Type* t, const Type* t0) {
1777 assert(t->meet(t0) == t, "Not monotonic");
1778 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1779 case Type::Int:
1780 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1781 break;
1782 case Type::Long:
1783 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1784 break;
1785 default:
1786 break;
1787 }
1788 return true;
1789 }
1790 #endif //ASSERT
1791
1792 //------------------------------analyze----------------------------------------
1793 void PhaseCCP::analyze() {
1794 // Initialize all types to TOP, optimistic analysis
1795 for (int i = C->unique() - 1; i >= 0; i--) {
1796 _types.map(i,Type::TOP);
1797 }
1798
1799 // Push root onto worklist
1800 Unique_Node_List worklist;
1801 worklist.push(C->root());
1802
1803 // Pull from worklist; compute new value; push changes out.
1804 // This loop is the meat of CCP.
1805 while( worklist.size() ) {
1806 Node *n = worklist.pop();
1807 const Type *t = n->Value(this);
1808 if (t != type(n)) {
1809 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1810 #ifndef PRODUCT
1811 if( TracePhaseCCP ) {
1812 t->dump();
1813 do { tty->print("\t"); } while (tty->position() < 16);
1814 n->dump();
1815 }
1816 #endif
1817 set_type(n, t);
1818 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1819 Node* m = n->fast_out(i); // Get user
1820 if (m->is_Region()) { // New path to Region? Must recheck Phis too
1821 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1822 Node* p = m->fast_out(i2); // Propagate changes to uses
1823 if (p->bottom_type() != type(p)) { // If not already bottomed out
1824 worklist.push(p); // Propagate change to user
1825 }
1826 }
1827 }
1828 // If we changed the receiver type to a call, we need to revisit
1829 // the Catch following the call. It's looking for a non-NULL
1830 // receiver to know when to enable the regular fall-through path
1831 // in addition to the NullPtrException path
1832 if (m->is_Call()) {
1833 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1834 Node* p = m->fast_out(i2); // Propagate changes to uses
1835 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1) {
1836 worklist.push(p->unique_out());
1837 }
1838 }
1839 }
1840 if (m->bottom_type() != type(m)) { // If not already bottomed out
1841 worklist.push(m); // Propagate change to user
1842 }
1843
1844 // CmpU nodes can get their type information from two nodes up in the
1845 // graph (instead of from the nodes immediately above). Make sure they
1846 // are added to the worklist if nodes they depend on are updated, since
1847 // they could be missed and get wrong types otherwise.
1848 uint m_op = m->Opcode();
1849 if (m_op == Op_AddI || m_op == Op_SubI) {
1850 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1851 Node* p = m->fast_out(i2); // Propagate changes to uses
1852 if (p->Opcode() == Op_CmpU) {
1853 // Got a CmpU which might need the new type information from node n.
1854 if(p->bottom_type() != type(p)) { // If not already bottomed out
1855 worklist.push(p); // Propagate change to user
1856 }
1857 }
1858 }
1859 }
1860 // If n is used in a counted loop exit condition then the type
1861 // of the counted loop's Phi depends on the type of n. See
1862 // PhiNode::Value().
1863 if (m_op == Op_CmpI) {
1864 PhiNode* phi = countedloop_phi_from_cmp((CmpINode*)m, n);
1865 if (phi != NULL) {
1866 worklist.push(phi);
1867 }
1868 }
1869 // Loading the java mirror from a Klass requires two loads and the type
1870 // of the mirror load depends on the type of 'n'. See LoadNode::Value().
1871 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1872 bool has_load_barriers = bs->has_load_barriers();
1873
1874 if (m_op == Op_LoadP && m->bottom_type()->isa_rawptr()) {
1875 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1876 Node* u = m->fast_out(i2);
1877 const Type* ut = u->bottom_type();
1878 if (u->Opcode() == Op_LoadP && ut->isa_instptr() && ut != type(u)) {
1879 if (has_load_barriers) {
1880 // Search for load barriers behind the load
1881 for (DUIterator_Fast i3max, i3 = u->fast_outs(i3max); i3 < i3max; i3++) {
1882 Node* b = u->fast_out(i3);
1883 if (bs->is_gc_barrier_node(b)) {
1884 worklist.push(b);
1885 }
1886 }
1887 }
1888 worklist.push(u);
1889 }
1890 }
1891 }
1892
1893 BarrierSet::barrier_set()->barrier_set_c2()->ccp_analyze(this, worklist, m);
1894 }
1895 }
1896 }
1897 }
1898
1899 //------------------------------do_transform-----------------------------------
1900 // Top level driver for the recursive transformer
1901 void PhaseCCP::do_transform() {
1902 // Correct leaves of new-space Nodes; they point to old-space.
1903 C->set_root( transform(C->root())->as_Root() );
1904 assert( C->top(), "missing TOP node" );
1905 assert( C->root(), "missing root" );
1906 }
1907
1908 //------------------------------transform--------------------------------------
1909 // Given a Node in old-space, clone him into new-space.
1910 // Convert any of his old-space children into new-space children.
1911 Node *PhaseCCP::transform( Node *n ) {
1912 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1913 if( new_node != NULL )
1914 return new_node; // Been there, done that, return old answer
1915 new_node = transform_once(n); // Check for constant
1916 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1917
1918 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1919 GrowableArray <Node *> trstack(C->live_nodes() >> 1);
1920
1921 trstack.push(new_node); // Process children of cloned node
1922 while ( trstack.is_nonempty() ) {
1923 Node *clone = trstack.pop();
1924 uint cnt = clone->req();
1925 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1926 Node *input = clone->in(i);
1927 if( input != NULL ) { // Ignore NULLs
1928 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1929 if( new_input == NULL ) {
1930 new_input = transform_once(input); // Check for constant
1931 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1932 trstack.push(new_input);
1933 }
1934 assert( new_input == clone->in(i), "insanity check");
1935 }
1936 }
1937 }
1938 return new_node;
1939 }
1940
1941
1942 //------------------------------transform_once---------------------------------
1943 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1944 Node *PhaseCCP::transform_once( Node *n ) {
1945 const Type *t = type(n);
1946 // Constant? Use constant Node instead
1947 if( t->singleton() ) {
1948 Node *nn = n; // Default is to return the original constant
1949 if( t == Type::TOP ) {
1950 // cache my top node on the Compile instance
1951 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1952 C->set_cached_top_node(ConNode::make(Type::TOP));
1953 set_type(C->top(), Type::TOP);
1954 }
1955 nn = C->top();
1956 }
1957 if( !n->is_Con() ) {
1958 if( t != Type::TOP ) {
1959 nn = makecon(t); // ConNode::make(t);
1960 NOT_PRODUCT( inc_constants(); )
1961 } else if( n->is_Region() ) { // Unreachable region
1962 // Note: nn == C->top()
1963 n->set_req(0, NULL); // Cut selfreference
1964 bool progress = true;
1965 uint max = n->outcnt();
1966 DUIterator i;
1967 while (progress) {
1968 progress = false;
1969 // Eagerly remove dead phis to avoid phis copies creation.
1970 for (i = n->outs(); n->has_out(i); i++) {
1971 Node* m = n->out(i);
1972 if (m->is_Phi()) {
1973 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1974 replace_node(m, nn);
1975 if (max != n->outcnt()) {
1976 progress = true;
1977 i = n->refresh_out_pos(i);
1978 max = n->outcnt();
1979 }
1980 }
1981 }
1982 }
1983 }
1984 replace_node(n,nn); // Update DefUse edges for new constant
1985 }
1986 return nn;
1987 }
1988
1989 // If x is a TypeNode, capture any more-precise type permanently into Node
1990 if (t != n->bottom_type()) {
1991 hash_delete(n); // changing bottom type may force a rehash
1992 n->raise_bottom_type(t);
1993 _worklist.push(n); // n re-enters the hash table via the worklist
1994 }
1995
1996 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1997 switch( n->Opcode() ) {
1998 case Op_FastLock: // Revisit FastLocks for lock coarsening
1999 case Op_If:
2000 case Op_CountedLoopEnd:
2001 case Op_Region:
2002 case Op_Loop:
2003 case Op_CountedLoop:
2004 case Op_Conv2B:
2005 case Op_Opaque1:
2006 case Op_Opaque2:
2007 _worklist.push(n);
2008 break;
2009 default:
2010 break;
2011 }
2012
2013 return n;
2014 }
2015
2016 //---------------------------------saturate------------------------------------
2017 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
2018 const Type* limit_type) const {
2019 const Type* wide_type = new_type->widen(old_type, limit_type);
2020 if (wide_type != new_type) { // did we widen?
2021 // If so, we may have widened beyond the limit type. Clip it back down.
2022 new_type = wide_type->filter(limit_type);
2023 }
2024 return new_type;
2025 }
2026
2027 //------------------------------print_statistics-------------------------------
2028 #ifndef PRODUCT
2029 void PhaseCCP::print_statistics() {
2030 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
2031 }
2032 #endif
2033
2034
2035 //=============================================================================
2036 #ifndef PRODUCT
2037 uint PhasePeephole::_total_peepholes = 0;
2038 #endif
2039 //------------------------------PhasePeephole----------------------------------
2040 // Conditional Constant Propagation, ala Wegman & Zadeck
2041 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
2042 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
2043 NOT_PRODUCT( clear_peepholes(); )
2044 }
2045
2046 #ifndef PRODUCT
2047 //------------------------------~PhasePeephole---------------------------------
2048 PhasePeephole::~PhasePeephole() {
2049 _total_peepholes += count_peepholes();
2050 }
2051 #endif
2052
2053 //------------------------------transform--------------------------------------
2054 Node *PhasePeephole::transform( Node *n ) {
2055 ShouldNotCallThis();
2056 return NULL;
2057 }
2058
2059 //------------------------------do_transform-----------------------------------
2060 void PhasePeephole::do_transform() {
2061 bool method_name_not_printed = true;
2062
2063 // Examine each basic block
2064 for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) {
2065 Block* block = _cfg.get_block(block_number);
2066 bool block_not_printed = true;
2067
2068 // and each instruction within a block
2069 uint end_index = block->number_of_nodes();
2070 // block->end_idx() not valid after PhaseRegAlloc
2071 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
2072 Node *n = block->get_node(instruction_index);
2073 if( n->is_Mach() ) {
2074 MachNode *m = n->as_Mach();
2075 int deleted_count = 0;
2076 // check for peephole opportunities
2077 MachNode *m2 = m->peephole(block, instruction_index, _regalloc, deleted_count);
2078 if( m2 != NULL ) {
2079 #ifndef PRODUCT
2080 if( PrintOptoPeephole ) {
2081 // Print method, first time only
2082 if( C->method() && method_name_not_printed ) {
2083 C->method()->print_short_name(); tty->cr();
2084 method_name_not_printed = false;
2085 }
2086 // Print this block
2087 if( Verbose && block_not_printed) {
2088 tty->print_cr("in block");
2089 block->dump();
2090 block_not_printed = false;
2091 }
2092 // Print instructions being deleted
2093 for( int i = (deleted_count - 1); i >= 0; --i ) {
2094 block->get_node(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
2095 }
2096 tty->print_cr("replaced with");
2097 // Print new instruction
2098 m2->format(_regalloc);
2099 tty->print("\n\n");
2100 }
2101 #endif
2102 // Remove old nodes from basic block and update instruction_index
2103 // (old nodes still exist and may have edges pointing to them
2104 // as register allocation info is stored in the allocator using
2105 // the node index to live range mappings.)
2106 uint safe_instruction_index = (instruction_index - deleted_count);
2107 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
2108 block->remove_node( instruction_index );
2109 }
2110 // install new node after safe_instruction_index
2111 block->insert_node(m2, safe_instruction_index + 1);
2112 end_index = block->number_of_nodes() - 1; // Recompute new block size
2113 NOT_PRODUCT( inc_peepholes(); )
2114 }
2115 }
2116 }
2117 }
2118 }
2119
2120 //------------------------------print_statistics-------------------------------
2121 #ifndef PRODUCT
2122 void PhasePeephole::print_statistics() {
2123 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
2124 }
2125 #endif
2126
2127
2128 //=============================================================================
2129 //------------------------------set_req_X--------------------------------------
2130 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
2131 assert( is_not_dead(n), "can not use dead node");
2132 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
2133 Node *old = in(i);
2134 set_req(i, n);
2135
2136 // old goes dead?
2137 if( old ) {
2138 switch (old->outcnt()) {
2139 case 0:
2140 // Put into the worklist to kill later. We do not kill it now because the
2141 // recursive kill will delete the current node (this) if dead-loop exists
2142 if (!old->is_top())
2143 igvn->_worklist.push( old );
2144 break;
2145 case 1:
2146 if( old->is_Store() || old->has_special_unique_user() )
2147 igvn->add_users_to_worklist( old );
2148 break;
2149 case 2:
2150 if( old->is_Store() )
2151 igvn->add_users_to_worklist( old );
2152 if( old->Opcode() == Op_Region )
2153 igvn->_worklist.push(old);
2154 break;
2155 case 3:
2156 if( old->Opcode() == Op_Region ) {
2157 igvn->_worklist.push(old);
2158 igvn->add_users_to_worklist( old );
2159 }
2160 break;
2161 default:
2162 break;
2163 }
2164
2165 BarrierSet::barrier_set()->barrier_set_c2()->enqueue_useful_gc_barrier(igvn, old);
2166 }
2167
2168 }
2169
2170 //-------------------------------replace_by-----------------------------------
2171 // Using def-use info, replace one node for another. Follow the def-use info
2172 // to all users of the OLD node. Then make all uses point to the NEW node.
2173 void Node::replace_by(Node *new_node) {
2174 assert(!is_top(), "top node has no DU info");
2175 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
2176 Node* use = last_out(i);
2177 uint uses_found = 0;
2178 for (uint j = 0; j < use->len(); j++) {
2179 if (use->in(j) == this) {
2180 if (j < use->req())
2181 use->set_req(j, new_node);
2182 else use->set_prec(j, new_node);
2183 uses_found++;
2184 }
2185 }
2186 i -= uses_found; // we deleted 1 or more copies of this edge
2187 }
2188 }
2189
2190 //=============================================================================
2191 //-----------------------------------------------------------------------------
2192 void Type_Array::grow( uint i ) {
2193 if( !_max ) {
2194 _max = 1;
2195 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
2196 _types[0] = NULL;
2197 }
2198 uint old = _max;
2199 while( i >= _max ) _max <<= 1; // Double to fit
2200 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
2201 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
2202 }
2203
2204 //------------------------------dump-------------------------------------------
2205 #ifndef PRODUCT
2206 void Type_Array::dump() const {
2207 uint max = Size();
2208 for( uint i = 0; i < max; i++ ) {
2209 if( _types[i] != NULL ) {
2210 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
2211 }
2212 }
2213 }
2214 #endif