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