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
466 assert(RenumberLiveNodes, "RenumberLiveNodes must be set to true for node renumbering to take place");
467 assert(C->live_nodes() == _useful.size(), "the number of live nodes must match the number of useful nodes");
468 assert(gvn->nodes_size() == 0, "GVN must not contain any nodes at this point");
469
470 uint old_unique_count = C->unique();
471 uint live_node_count = C->live_nodes();
472 uint worklist_size = worklist->size();
473
474 // Storage for the updated type information.
475 Type_Array new_type_array(C->comp_arena());
476
477 // Iterate over the set of live nodes.
478 uint current_idx = 0; // The current new node ID. Incremented after every assignment.
479 for (uint i = 0; i < _useful.size(); i++) {
480 Node* n = _useful.at(i);
481 // Sanity check that fails if we ever decide to execute this phase after EA
482 assert(!n->is_Phi() || n->as_Phi()->inst_mem_id() == -1, "should not be linked to data Phi");
483 const Type* type = gvn->type_or_null(n);
484 new_type_array.map(current_idx, type);
485
486 bool in_worklist = false;
487 if (worklist->member(n)) {
488 in_worklist = true;
489 }
490
491 n->set_idx(current_idx); // Update node ID.
492
493 if (in_worklist) {
494 new_worklist->push(n);
495 }
496
497 current_idx++;
498 }
499
500 assert(worklist_size == new_worklist->size(), "the new worklist must have the same size as the original worklist");
501 assert(live_node_count == current_idx, "all live nodes must be processed");
502
503 // Replace the compiler's type information with the updated type information.
504 gvn->replace_types(new_type_array);
505
506 // Update the unique node count of the compilation to the number of currently live nodes.
507 C->set_unique(live_node_count);
508
509 // Set the dead node count to 0 and reset dead node list.
510 C->reset_dead_node_list();
511 }
512
513
514 //=============================================================================
515 //------------------------------PhaseTransform---------------------------------
516 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
517 _arena(Thread::current()->resource_area()),
518 _nodes(_arena),
519 _types(_arena)
520 {
521 init_con_caches();
522 #ifndef PRODUCT
523 clear_progress();
524 clear_transforms();
525 set_allow_progress(true);
526 #endif
527 // Force allocation for currently existing nodes
528 _types.map(C->unique(), NULL);
529 }
530
531 //------------------------------PhaseTransform---------------------------------
532 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
533 _arena(arena),
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 // Initialize with previously generated type information
549 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
550 _arena(pt->_arena),
551 _nodes(pt->_nodes),
552 _types(pt->_types)
553 {
554 init_con_caches();
555 #ifndef PRODUCT
556 clear_progress();
557 clear_transforms();
558 set_allow_progress(true);
559 #endif
560 }
561
562 void PhaseTransform::init_con_caches() {
563 memset(_icons,0,sizeof(_icons));
564 memset(_lcons,0,sizeof(_lcons));
565 memset(_zcons,0,sizeof(_zcons));
566 }
567
568
569 //--------------------------------find_int_type--------------------------------
570 const TypeInt* PhaseTransform::find_int_type(Node* n) {
571 if (n == NULL) return NULL;
572 // Call type_or_null(n) to determine node's type since we might be in
573 // parse phase and call n->Value() may return wrong type.
574 // (For example, a phi node at the beginning of loop parsing is not ready.)
575 const Type* t = type_or_null(n);
576 if (t == NULL) return NULL;
577 return t->isa_int();
578 }
579
580
581 //-------------------------------find_long_type--------------------------------
582 const TypeLong* PhaseTransform::find_long_type(Node* n) {
583 if (n == NULL) return NULL;
584 // (See comment above on type_or_null.)
585 const Type* t = type_or_null(n);
586 if (t == NULL) return NULL;
587 return t->isa_long();
588 }
589
590
591 #ifndef PRODUCT
592 void PhaseTransform::dump_old2new_map() const {
593 _nodes.dump();
594 }
595
596 void PhaseTransform::dump_new( uint nidx ) const {
597 for( uint i=0; i<_nodes.Size(); i++ )
598 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
599 _nodes[i]->dump();
600 tty->cr();
601 tty->print_cr("Old index= %d",i);
602 return;
603 }
604 tty->print_cr("Node %d not found in the new indices", nidx);
605 }
606
607 //------------------------------dump_types-------------------------------------
608 void PhaseTransform::dump_types( ) const {
609 _types.dump();
610 }
611
612 //------------------------------dump_nodes_and_types---------------------------
613 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
614 VectorSet visited(Thread::current()->resource_area());
615 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
616 }
617
618 //------------------------------dump_nodes_and_types_recur---------------------
619 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
620 if( !n ) return;
621 if( depth == 0 ) return;
622 if( visited.test_set(n->_idx) ) return;
623 for( uint i=0; i<n->len(); i++ ) {
624 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
625 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
626 }
627 n->dump();
628 if (type_or_null(n) != NULL) {
629 tty->print(" "); type(n)->dump(); tty->cr();
630 }
631 }
632
633 #endif
634
635
636 //=============================================================================
637 //------------------------------PhaseValues------------------------------------
638 // Set minimum table size to "255"
639 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
640 NOT_PRODUCT( clear_new_values(); )
641 }
642
643 //------------------------------PhaseValues------------------------------------
644 // Set minimum table size to "255"
645 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
646 _table(&ptv->_table) {
647 NOT_PRODUCT( clear_new_values(); )
648 }
649
650 //------------------------------PhaseValues------------------------------------
651 // Used by +VerifyOpto. Clear out hash table but copy _types array.
652 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
653 _table(ptv->arena(),ptv->_table.size()) {
654 NOT_PRODUCT( clear_new_values(); )
655 }
656
657 //------------------------------~PhaseValues-----------------------------------
658 #ifndef PRODUCT
659 PhaseValues::~PhaseValues() {
660 _table.dump();
661
662 // Statistics for value progress and efficiency
663 if( PrintCompilation && Verbose && WizardMode ) {
664 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
665 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
666 if( made_transforms() != 0 ) {
667 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
668 } else {
669 tty->cr();
670 }
671 }
672 }
673 #endif
674
675 //------------------------------makecon----------------------------------------
676 ConNode* PhaseTransform::makecon(const Type *t) {
677 assert(t->singleton(), "must be a constant");
678 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
679 switch (t->base()) { // fast paths
680 case Type::Half:
681 case Type::Top: return (ConNode*) C->top();
682 case Type::Int: return intcon( t->is_int()->get_con() );
683 case Type::Long: return longcon( t->is_long()->get_con() );
684 default: break;
685 }
686 if (t->is_zero_type())
687 return zerocon(t->basic_type());
688 return uncached_makecon(t);
689 }
690
691 //--------------------------uncached_makecon-----------------------------------
692 // Make an idealized constant - one of ConINode, ConPNode, etc.
693 ConNode* PhaseValues::uncached_makecon(const Type *t) {
694 assert(t->singleton(), "must be a constant");
695 ConNode* x = ConNode::make(t);
696 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
697 if (k == NULL) {
698 set_type(x, t); // Missed, provide type mapping
699 GrowableArray<Node_Notes*>* nna = C->node_note_array();
700 if (nna != NULL) {
701 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
702 loc->clear(); // do not put debug info on constants
703 }
704 } else {
705 x->destruct(); // Hit, destroy duplicate constant
706 x = k; // use existing constant
707 }
708 return x;
709 }
710
711 //------------------------------intcon-----------------------------------------
712 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
713 ConINode* PhaseTransform::intcon(jint i) {
714 // Small integer? Check cache! Check that cached node is not dead
715 if (i >= _icon_min && i <= _icon_max) {
716 ConINode* icon = _icons[i-_icon_min];
717 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
718 return icon;
719 }
720 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
721 assert(icon->is_Con(), "");
722 if (i >= _icon_min && i <= _icon_max)
723 _icons[i-_icon_min] = icon; // Cache small integers
724 return icon;
725 }
726
727 //------------------------------longcon----------------------------------------
728 // Fast long constant.
729 ConLNode* PhaseTransform::longcon(jlong l) {
730 // Small integer? Check cache! Check that cached node is not dead
731 if (l >= _lcon_min && l <= _lcon_max) {
732 ConLNode* lcon = _lcons[l-_lcon_min];
733 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
734 return lcon;
735 }
736 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
737 assert(lcon->is_Con(), "");
738 if (l >= _lcon_min && l <= _lcon_max)
739 _lcons[l-_lcon_min] = lcon; // Cache small integers
740 return lcon;
741 }
742
743 //------------------------------zerocon-----------------------------------------
744 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
745 ConNode* PhaseTransform::zerocon(BasicType bt) {
746 assert((uint)bt <= _zcon_max, "domain check");
747 ConNode* zcon = _zcons[bt];
748 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
749 return zcon;
750 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
751 _zcons[bt] = zcon;
752 return zcon;
753 }
754
755
756
757 //=============================================================================
758 Node* PhaseGVN::apply_ideal(Node* k, bool can_reshape) {
759 Node* i = BarrierSet::barrier_set()->barrier_set_c2()->ideal_node(this, k, can_reshape);
760 if (i == NULL) {
761 i = k->Ideal(this, can_reshape);
762 }
763 return i;
764 }
765
766 Node* PhaseGVN::apply_identity(Node* k) {
767 Node* i = BarrierSet::barrier_set()->barrier_set_c2()->identity_node(this, k);
768 if (i == k) {
769 i = k->Identity(this);
770 }
771 return i;
772 }
773
774 //------------------------------transform--------------------------------------
775 // Return a node which computes the same function as this node, but in a
776 // faster or cheaper fashion.
777 Node *PhaseGVN::transform( Node *n ) {
778 return transform_no_reclaim(n);
779 }
780
781 //------------------------------transform--------------------------------------
782 // Return a node which computes the same function as this node, but
783 // in a faster or cheaper fashion.
784 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
785 NOT_PRODUCT( set_transforms(); )
786
787 // Apply the Ideal call in a loop until it no longer applies
788 Node *k = n;
789 NOT_PRODUCT( uint loop_count = 0; )
790 while( 1 ) {
791 Node *i = apply_ideal(k, /*can_reshape=*/false);
792 if( !i ) break;
793 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
794 k = i;
795 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
796 }
797 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
798
799
800 // If brand new node, make space in type array.
801 ensure_type_or_null(k);
802
803 // Since I just called 'Value' to compute the set of run-time values
804 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
805 // cache Value. Later requests for the local phase->type of this Node can
806 // use the cached Value instead of suffering with 'bottom_type'.
807 const Type *t = k->Value(this); // Get runtime Value set
808 assert(t != NULL, "value sanity");
809 if (type_or_null(k) != t) {
810 #ifndef PRODUCT
811 // Do not count initial visit to node as a transformation
812 if (type_or_null(k) == NULL) {
813 inc_new_values();
814 set_progress();
815 }
816 #endif
817 set_type(k, t);
818 // If k is a TypeNode, capture any more-precise type permanently into Node
819 k->raise_bottom_type(t);
820 }
821
822 if( t->singleton() && !k->is_Con() ) {
823 NOT_PRODUCT( set_progress(); )
824 return makecon(t); // Turn into a constant
825 }
826
827 // Now check for Identities
828 Node *i = apply_identity(k); // Look for a nearby replacement
829 if( i != k ) { // Found? Return replacement!
830 NOT_PRODUCT( set_progress(); )
831 return i;
832 }
833
834 // Global Value Numbering
835 i = hash_find_insert(k); // Insert if new
836 if( i && (i != k) ) {
837 // Return the pre-existing node
838 NOT_PRODUCT( set_progress(); )
839 return i;
840 }
841
842 // Return Idealized original
843 return k;
844 }
845
846 bool PhaseGVN::is_dominator_helper(Node *d, Node *n, bool linear_only) {
847 if (d->is_top() || n->is_top()) {
848 return false;
849 }
850 assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes");
851 int i = 0;
852 while (d != n) {
853 n = IfNode::up_one_dom(n, linear_only);
854 i++;
855 if (n == NULL || i >= 10) {
856 return false;
857 }
858 }
859 return true;
860 }
861
862 #ifdef ASSERT
863 //------------------------------dead_loop_check--------------------------------
864 // Check for a simple dead loop when a data node references itself directly
865 // or through an other data node excluding cons and phis.
866 void PhaseGVN::dead_loop_check( Node *n ) {
867 // Phi may reference itself in a loop
868 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
869 // Do 2 levels check and only data inputs.
870 bool no_dead_loop = true;
871 uint cnt = n->req();
872 for (uint i = 1; i < cnt && no_dead_loop; i++) {
873 Node *in = n->in(i);
874 if (in == n) {
875 no_dead_loop = false;
876 } else if (in != NULL && !in->is_dead_loop_safe()) {
877 uint icnt = in->req();
878 for (uint j = 1; j < icnt && no_dead_loop; j++) {
879 if (in->in(j) == n || in->in(j) == in)
880 no_dead_loop = false;
881 }
882 }
883 }
884 if (!no_dead_loop) n->dump(3);
885 assert(no_dead_loop, "dead loop detected");
886 }
887 }
888 #endif
889
890 //=============================================================================
891 //------------------------------PhaseIterGVN-----------------------------------
892 // Initialize hash table to fresh and clean for +VerifyOpto
893 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy),
894 _delay_transform(false),
895 _stack(C->live_nodes() >> 1),
896 _worklist( ) {
897 }
898
899 //------------------------------PhaseIterGVN-----------------------------------
900 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
901 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
902 _delay_transform(igvn->_delay_transform),
903 _stack( igvn->_stack ),
904 _worklist( igvn->_worklist )
905 {
906 }
907
908 //------------------------------PhaseIterGVN-----------------------------------
909 // Initialize with previous PhaseGVN info from Parser
910 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
911 _delay_transform(false),
912 // TODO: Before incremental inlining it was allocated only once and it was fine. Now that
913 // the constructor is used in incremental inlining, this consumes too much memory:
914 // _stack(C->live_nodes() >> 1),
915 // So, as a band-aid, we replace this by:
916 _stack(C->comp_arena(), 32),
917 _worklist(*C->for_igvn())
918 {
919 uint max;
920
921 // Dead nodes in the hash table inherited from GVN were not treated as
922 // roots during def-use info creation; hence they represent an invisible
923 // use. Clear them out.
924 max = _table.size();
925 for( uint i = 0; i < max; ++i ) {
926 Node *n = _table.at(i);
927 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
928 if( n->is_top() ) continue;
929 assert( false, "Parse::remove_useless_nodes missed this node");
930 hash_delete(n);
931 }
932 }
933
934 // Any Phis or Regions on the worklist probably had uses that could not
935 // make more progress because the uses were made while the Phis and Regions
936 // were in half-built states. Put all uses of Phis and Regions on worklist.
937 max = _worklist.size();
938 for( uint j = 0; j < max; j++ ) {
939 Node *n = _worklist.at(j);
940 uint uop = n->Opcode();
941 if( uop == Op_Phi || uop == Op_Region ||
942 n->is_Type() ||
943 n->is_Mem() )
944 add_users_to_worklist(n);
945 }
946
947 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
948 bs->add_users_to_worklist(&_worklist);
949 }
950
951 /**
952 * Initialize worklist for each node.
953 */
954 void PhaseIterGVN::init_worklist(Node* first) {
955 Unique_Node_List to_process;
956 to_process.push(first);
957
958 while (to_process.size() > 0) {
959 Node* n = to_process.pop();
960 if (!_worklist.member(n)) {
961 _worklist.push(n);
962
963 uint cnt = n->req();
964 for(uint i = 0; i < cnt; i++) {
965 Node* m = n->in(i);
966 if (m != NULL) {
967 to_process.push(m);
968 }
969 }
970 }
971 }
972 }
973
974 #ifndef PRODUCT
975 void PhaseIterGVN::verify_step(Node* n) {
976 if (VerifyIterativeGVN) {
977 _verify_window[_verify_counter % _verify_window_size] = n;
978 ++_verify_counter;
979 ResourceMark rm;
980 ResourceArea* area = Thread::current()->resource_area();
981 VectorSet old_space(area), new_space(area);
982 if (C->unique() < 1000 ||
983 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
984 ++_verify_full_passes;
985 Node::verify_recur(C->root(), -1, old_space, new_space);
986 }
987 const int verify_depth = 4;
988 for ( int i = 0; i < _verify_window_size; i++ ) {
989 Node* n = _verify_window[i];
990 if ( n == NULL ) continue;
991 if( n->in(0) == NodeSentinel ) { // xform_idom
992 _verify_window[i] = n->in(1);
993 --i; continue;
994 }
995 // Typical fanout is 1-2, so this call visits about 6 nodes.
996 Node::verify_recur(n, verify_depth, old_space, new_space);
997 }
998 }
999 }
1000
1001 void PhaseIterGVN::trace_PhaseIterGVN(Node* n, Node* nn, const Type* oldtype) {
1002 if (TraceIterativeGVN) {
1003 uint wlsize = _worklist.size();
1004 const Type* newtype = type_or_null(n);
1005 if (nn != n) {
1006 // print old node
1007 tty->print("< ");
1008 if (oldtype != newtype && oldtype != NULL) {
1009 oldtype->dump();
1010 }
1011 do { tty->print("\t"); } while (tty->position() < 16);
1012 tty->print("<");
1013 n->dump();
1014 }
1015 if (oldtype != newtype || nn != n) {
1016 // print new node and/or new type
1017 if (oldtype == NULL) {
1018 tty->print("* ");
1019 } else if (nn != n) {
1020 tty->print("> ");
1021 } else {
1022 tty->print("= ");
1023 }
1024 if (newtype == NULL) {
1025 tty->print("null");
1026 } else {
1027 newtype->dump();
1028 }
1029 do { tty->print("\t"); } while (tty->position() < 16);
1030 nn->dump();
1031 }
1032 if (Verbose && wlsize < _worklist.size()) {
1033 tty->print(" Push {");
1034 while (wlsize != _worklist.size()) {
1035 Node* pushed = _worklist.at(wlsize++);
1036 tty->print(" %d", pushed->_idx);
1037 }
1038 tty->print_cr(" }");
1039 }
1040 if (nn != n) {
1041 // ignore n, it might be subsumed
1042 verify_step((Node*) NULL);
1043 }
1044 }
1045 }
1046
1047 void PhaseIterGVN::init_verifyPhaseIterGVN() {
1048 _verify_counter = 0;
1049 _verify_full_passes = 0;
1050 for (int i = 0; i < _verify_window_size; i++) {
1051 _verify_window[i] = NULL;
1052 }
1053 #ifdef ASSERT
1054 // Verify that all modified nodes are on _worklist
1055 Unique_Node_List* modified_list = C->modified_nodes();
1056 while (modified_list != NULL && modified_list->size()) {
1057 Node* n = modified_list->pop();
1058 if (n->outcnt() != 0 && !n->is_Con() && !_worklist.member(n)) {
1059 n->dump();
1060 assert(false, "modified node is not on IGVN._worklist");
1061 }
1062 }
1063 #endif
1064 }
1065
1066 void PhaseIterGVN::verify_PhaseIterGVN() {
1067 #ifdef ASSERT
1068 // Verify nodes with changed inputs.
1069 Unique_Node_List* modified_list = C->modified_nodes();
1070 while (modified_list != NULL && modified_list->size()) {
1071 Node* n = modified_list->pop();
1072 if (n->outcnt() != 0 && !n->is_Con()) { // skip dead and Con nodes
1073 n->dump();
1074 assert(false, "modified node was not processed by IGVN.transform_old()");
1075 }
1076 }
1077 #endif
1078
1079 C->verify_graph_edges();
1080 if( VerifyOpto && allow_progress() ) {
1081 // Must turn off allow_progress to enable assert and break recursion
1082 C->root()->verify();
1083 { // Check if any progress was missed using IterGVN
1084 // Def-Use info enables transformations not attempted in wash-pass
1085 // e.g. Region/Phi cleanup, ...
1086 // Null-check elision -- may not have reached fixpoint
1087 // do not propagate to dominated nodes
1088 ResourceMark rm;
1089 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
1090 // Fill worklist completely
1091 igvn2.init_worklist(C->root());
1092
1093 igvn2.set_allow_progress(false);
1094 igvn2.optimize();
1095 igvn2.set_allow_progress(true);
1096 }
1097 }
1098 if (VerifyIterativeGVN && PrintOpto) {
1099 if (_verify_counter == _verify_full_passes) {
1100 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
1101 (int) _verify_full_passes);
1102 } else {
1103 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
1104 (int) _verify_counter, (int) _verify_full_passes);
1105 }
1106 }
1107
1108 #ifdef ASSERT
1109 while (modified_list->size()) {
1110 Node* n = modified_list->pop();
1111 n->dump();
1112 assert(false, "VerifyIterativeGVN: new modified node was added");
1113 }
1114 #endif
1115 }
1116 #endif /* PRODUCT */
1117
1118 #ifdef ASSERT
1119 /**
1120 * Dumps information that can help to debug the problem. A debug
1121 * build fails with an assert.
1122 */
1123 void PhaseIterGVN::dump_infinite_loop_info(Node* n) {
1124 n->dump(4);
1125 _worklist.dump();
1126 assert(false, "infinite loop in PhaseIterGVN::optimize");
1127 }
1128
1129 /**
1130 * Prints out information about IGVN if the 'verbose' option is used.
1131 */
1132 void PhaseIterGVN::trace_PhaseIterGVN_verbose(Node* n, int num_processed) {
1133 if (TraceIterativeGVN && Verbose) {
1134 tty->print(" Pop ");
1135 n->dump();
1136 if ((num_processed % 100) == 0) {
1137 _worklist.print_set();
1138 }
1139 }
1140 }
1141 #endif /* ASSERT */
1142
1143 void PhaseIterGVN::optimize() {
1144 DEBUG_ONLY(uint num_processed = 0;)
1145 NOT_PRODUCT(init_verifyPhaseIterGVN();)
1146
1147 uint loop_count = 0;
1148 // Pull from worklist and transform the node. If the node has changed,
1149 // update edge info and put uses on worklist.
1150 while(_worklist.size()) {
1151 if (C->check_node_count(NodeLimitFudgeFactor * 2, "Out of nodes")) {
1152 return;
1153 }
1154 Node* n = _worklist.pop();
1155 if (++loop_count >= K * C->live_nodes()) {
1156 DEBUG_ONLY(dump_infinite_loop_info(n);)
1157 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
1158 return;
1159 }
1160 DEBUG_ONLY(trace_PhaseIterGVN_verbose(n, num_processed++);)
1161 if (n->outcnt() != 0) {
1162 NOT_PRODUCT(const Type* oldtype = type_or_null(n));
1163 // Do the transformation
1164 Node* nn = transform_old(n);
1165 NOT_PRODUCT(trace_PhaseIterGVN(n, nn, oldtype);)
1166 } else if (!n->is_top()) {
1167 remove_dead_node(n);
1168 }
1169 }
1170 NOT_PRODUCT(verify_PhaseIterGVN();)
1171 }
1172
1173
1174 /**
1175 * Register a new node with the optimizer. Update the types array, the def-use
1176 * info. Put on worklist.
1177 */
1178 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1179 set_type_bottom(n);
1180 _worklist.push(n);
1181 if (orig != NULL) C->copy_node_notes_to(n, orig);
1182 return n;
1183 }
1184
1185 //------------------------------transform--------------------------------------
1186 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1187 Node *PhaseIterGVN::transform( Node *n ) {
1188 if (_delay_transform) {
1189 // Register the node but don't optimize for now
1190 register_new_node_with_optimizer(n);
1191 return n;
1192 }
1193
1194 // If brand new node, make space in type array, and give it a type.
1195 ensure_type_or_null(n);
1196 if (type_or_null(n) == NULL) {
1197 set_type_bottom(n);
1198 }
1199
1200 return transform_old(n);
1201 }
1202
1203 Node *PhaseIterGVN::transform_old(Node* n) {
1204 DEBUG_ONLY(uint loop_count = 0;);
1205 NOT_PRODUCT(set_transforms());
1206
1207 // Remove 'n' from hash table in case it gets modified
1208 _table.hash_delete(n);
1209 if (VerifyIterativeGVN) {
1210 assert(!_table.find_index(n->_idx), "found duplicate entry in table");
1211 }
1212
1213 // Apply the Ideal call in a loop until it no longer applies
1214 Node* k = n;
1215 DEBUG_ONLY(dead_loop_check(k);)
1216 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1217 C->remove_modified_node(k);
1218 Node* i = apply_ideal(k, /*can_reshape=*/true);
1219 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1220 #ifndef PRODUCT
1221 verify_step(k);
1222 if (i && VerifyOpto ) {
1223 if (!allow_progress()) {
1224 if (i->is_Add() && (i->outcnt() == 1)) {
1225 // Switched input to left side because this is the only use
1226 } else if (i->is_If() && (i->in(0) == NULL)) {
1227 // This IF is dead because it is dominated by an equivalent IF When
1228 // dominating if changed, info is not propagated sparsely to 'this'
1229 // Propagating this info further will spuriously identify other
1230 // progress.
1231 return i;
1232 } else
1233 set_progress();
1234 } else {
1235 set_progress();
1236 }
1237 }
1238 #endif
1239
1240 while (i != NULL) {
1241 #ifdef ASSERT
1242 if (loop_count >= K) {
1243 dump_infinite_loop_info(i);
1244 }
1245 loop_count++;
1246 #endif
1247 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1248 // Made a change; put users of original Node on worklist
1249 add_users_to_worklist(k);
1250 // Replacing root of transform tree?
1251 if (k != i) {
1252 // Make users of old Node now use new.
1253 subsume_node(k, i);
1254 k = i;
1255 }
1256 DEBUG_ONLY(dead_loop_check(k);)
1257 // Try idealizing again
1258 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1259 C->remove_modified_node(k);
1260 i = apply_ideal(k, /*can_reshape=*/true);
1261 assert(i != k || is_new || (i->outcnt() > 0), "don't return dead nodes");
1262 #ifndef PRODUCT
1263 verify_step(k);
1264 if (i && VerifyOpto) {
1265 set_progress();
1266 }
1267 #endif
1268 }
1269
1270 // If brand new node, make space in type array.
1271 ensure_type_or_null(k);
1272
1273 // See what kind of values 'k' takes on at runtime
1274 const Type* t = k->Value(this);
1275 assert(t != NULL, "value sanity");
1276
1277 // Since I just called 'Value' to compute the set of run-time values
1278 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1279 // cache Value. Later requests for the local phase->type of this Node can
1280 // use the cached Value instead of suffering with 'bottom_type'.
1281 if (type_or_null(k) != t) {
1282 #ifndef PRODUCT
1283 inc_new_values();
1284 set_progress();
1285 #endif
1286 set_type(k, t);
1287 // If k is a TypeNode, capture any more-precise type permanently into Node
1288 k->raise_bottom_type(t);
1289 // Move users of node to worklist
1290 add_users_to_worklist(k);
1291 }
1292 // If 'k' computes a constant, replace it with a constant
1293 if (t->singleton() && !k->is_Con()) {
1294 NOT_PRODUCT(set_progress();)
1295 Node* con = makecon(t); // Make a constant
1296 add_users_to_worklist(k);
1297 subsume_node(k, con); // Everybody using k now uses con
1298 return con;
1299 }
1300
1301 // Now check for Identities
1302 i = apply_identity(k); // Look for a nearby replacement
1303 if (i != k) { // Found? Return replacement!
1304 NOT_PRODUCT(set_progress();)
1305 add_users_to_worklist(k);
1306 subsume_node(k, i); // Everybody using k now uses i
1307 return i;
1308 }
1309
1310 // Global Value Numbering
1311 i = hash_find_insert(k); // Check for pre-existing node
1312 if (i && (i != k)) {
1313 // Return the pre-existing node if it isn't dead
1314 NOT_PRODUCT(set_progress();)
1315 add_users_to_worklist(k);
1316 subsume_node(k, i); // Everybody using k now uses i
1317 return i;
1318 }
1319
1320 // Return Idealized original
1321 return k;
1322 }
1323
1324 //---------------------------------saturate------------------------------------
1325 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1326 const Type* limit_type) const {
1327 return new_type->narrow(old_type);
1328 }
1329
1330 //------------------------------remove_globally_dead_node----------------------
1331 // Kill a globally dead Node. All uses are also globally dead and are
1332 // aggressively trimmed.
1333 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1334 enum DeleteProgress {
1335 PROCESS_INPUTS,
1336 PROCESS_OUTPUTS
1337 };
1338 assert(_stack.is_empty(), "not empty");
1339 _stack.push(dead, PROCESS_INPUTS);
1340
1341 while (_stack.is_nonempty()) {
1342 dead = _stack.node();
1343 if (dead->Opcode() == Op_SafePoint) {
1344 dead->as_SafePoint()->disconnect_from_root(this);
1345 }
1346 uint progress_state = _stack.index();
1347 assert(dead != C->root(), "killing root, eh?");
1348 assert(!dead->is_top(), "add check for top when pushing");
1349 NOT_PRODUCT( set_progress(); )
1350 if (progress_state == PROCESS_INPUTS) {
1351 // After following inputs, continue to outputs
1352 _stack.set_index(PROCESS_OUTPUTS);
1353 if (!dead->is_Con()) { // Don't kill cons but uses
1354 bool recurse = false;
1355 // Remove from hash table
1356 _table.hash_delete( dead );
1357 // Smash all inputs to 'dead', isolating him completely
1358 for (uint i = 0; i < dead->req(); i++) {
1359 Node *in = dead->in(i);
1360 if (in != NULL && in != C->top()) { // Points to something?
1361 int nrep = dead->replace_edge(in, NULL); // Kill edges
1362 assert((nrep > 0), "sanity");
1363 if (in->outcnt() == 0) { // Made input go dead?
1364 _stack.push(in, PROCESS_INPUTS); // Recursively remove
1365 recurse = true;
1366 } else if (in->outcnt() == 1 &&
1367 in->has_special_unique_user()) {
1368 _worklist.push(in->unique_out());
1369 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1370 if (in->Opcode() == Op_Region) {
1371 _worklist.push(in);
1372 } else if (in->is_Store()) {
1373 DUIterator_Fast imax, i = in->fast_outs(imax);
1374 _worklist.push(in->fast_out(i));
1375 i++;
1376 if (in->outcnt() == 2) {
1377 _worklist.push(in->fast_out(i));
1378 i++;
1379 }
1380 assert(!(i < imax), "sanity");
1381 }
1382 } else {
1383 BarrierSet::barrier_set()->barrier_set_c2()->enqueue_useful_gc_barrier(this, in);
1384 }
1385 if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory &&
1386 in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) {
1387 // A Load that directly follows an InitializeNode is
1388 // going away. The Stores that follow are candidates
1389 // again to be captured by the InitializeNode.
1390 for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) {
1391 Node *n = in->fast_out(j);
1392 if (n->is_Store()) {
1393 _worklist.push(n);
1394 }
1395 }
1396 }
1397 } // if (in != NULL && in != C->top())
1398 } // for (uint i = 0; i < dead->req(); i++)
1399 if (recurse) {
1400 continue;
1401 }
1402 } // if (!dead->is_Con())
1403 } // if (progress_state == PROCESS_INPUTS)
1404
1405 // Aggressively kill globally dead uses
1406 // (Rather than pushing all the outs at once, we push one at a time,
1407 // plus the parent to resume later, because of the indefinite number
1408 // of edge deletions per loop trip.)
1409 if (dead->outcnt() > 0) {
1410 // Recursively remove output edges
1411 _stack.push(dead->raw_out(0), PROCESS_INPUTS);
1412 } else {
1413 // Finished disconnecting all input and output edges.
1414 _stack.pop();
1415 // Remove dead node from iterative worklist
1416 _worklist.remove(dead);
1417 C->remove_modified_node(dead);
1418 // Constant node that has no out-edges and has only one in-edge from
1419 // root is usually dead. However, sometimes reshaping walk makes
1420 // it reachable by adding use edges. So, we will NOT count Con nodes
1421 // as dead to be conservative about the dead node count at any
1422 // given time.
1423 if (!dead->is_Con()) {
1424 C->record_dead_node(dead->_idx);
1425 }
1426 if (dead->is_macro()) {
1427 C->remove_macro_node(dead);
1428 }
1429 if (dead->is_expensive()) {
1430 C->remove_expensive_node(dead);
1431 }
1432 CastIINode* cast = dead->isa_CastII();
1433 if (cast != NULL && cast->has_range_check()) {
1434 C->remove_range_check_cast(cast);
1435 }
1436 if (dead->Opcode() == Op_Opaque4) {
1437 C->remove_opaque4_node(dead);
1438 }
1439 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1440 bs->unregister_potential_barrier_node(dead);
1441 }
1442 } // while (_stack.is_nonempty())
1443 }
1444
1445 //------------------------------subsume_node-----------------------------------
1446 // Remove users from node 'old' and add them to node 'nn'.
1447 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1448 if (old->Opcode() == Op_SafePoint) {
1449 old->as_SafePoint()->disconnect_from_root(this);
1450 }
1451 assert( old != hash_find(old), "should already been removed" );
1452 assert( old != C->top(), "cannot subsume top node");
1453 // Copy debug or profile information to the new version:
1454 C->copy_node_notes_to(nn, old);
1455 // Move users of node 'old' to node 'nn'
1456 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1457 Node* use = old->last_out(i); // for each use...
1458 // use might need re-hashing (but it won't if it's a new node)
1459 rehash_node_delayed(use);
1460 // Update use-def info as well
1461 // We remove all occurrences of old within use->in,
1462 // so as to avoid rehashing any node more than once.
1463 // The hash table probe swamps any outer loop overhead.
1464 uint num_edges = 0;
1465 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1466 if (use->in(j) == old) {
1467 use->set_req(j, nn);
1468 ++num_edges;
1469 }
1470 }
1471 i -= num_edges; // we deleted 1 or more copies of this edge
1472 }
1473
1474 // Search for instance field data PhiNodes in the same region pointing to the old
1475 // memory PhiNode and update their instance memory ids to point to the new node.
1476 if (old->is_Phi() && old->as_Phi()->type()->has_memory() && old->in(0) != NULL) {
1477 Node* region = old->in(0);
1478 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1479 PhiNode* phi = region->fast_out(i)->isa_Phi();
1480 if (phi != NULL && phi->inst_mem_id() == (int)old->_idx) {
1481 phi->set_inst_mem_id((int)nn->_idx);
1482 }
1483 }
1484 }
1485
1486 // Smash all inputs to 'old', isolating him completely
1487 Node *temp = new Node(1);
1488 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1489 remove_dead_node( old );
1490 temp->del_req(0); // Yank bogus edge
1491 #ifndef PRODUCT
1492 if( VerifyIterativeGVN ) {
1493 for ( int i = 0; i < _verify_window_size; i++ ) {
1494 if ( _verify_window[i] == old )
1495 _verify_window[i] = nn;
1496 }
1497 }
1498 #endif
1499 _worklist.remove(temp); // this can be necessary
1500 temp->destruct(); // reuse the _idx of this little guy
1501 }
1502
1503 //------------------------------add_users_to_worklist--------------------------
1504 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1505 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1506 _worklist.push(n->fast_out(i)); // Push on worklist
1507 }
1508 }
1509
1510 // Return counted loop Phi if as a counted loop exit condition, cmp
1511 // compares the the induction variable with n
1512 static PhiNode* countedloop_phi_from_cmp(CmpINode* cmp, Node* n) {
1513 for (DUIterator_Fast imax, i = cmp->fast_outs(imax); i < imax; i++) {
1514 Node* bol = cmp->fast_out(i);
1515 for (DUIterator_Fast i2max, i2 = bol->fast_outs(i2max); i2 < i2max; i2++) {
1516 Node* iff = bol->fast_out(i2);
1517 if (iff->is_CountedLoopEnd()) {
1518 CountedLoopEndNode* cle = iff->as_CountedLoopEnd();
1519 if (cle->limit() == n) {
1520 PhiNode* phi = cle->phi();
1521 if (phi != NULL) {
1522 return phi;
1523 }
1524 }
1525 }
1526 }
1527 }
1528 return NULL;
1529 }
1530
1531 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1532 add_users_to_worklist0(n);
1533
1534 // Move users of node to worklist
1535 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1536 Node* use = n->fast_out(i); // Get use
1537
1538 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1539 use->is_Store() ) // Enable store/load same address
1540 add_users_to_worklist0(use);
1541
1542 // If we changed the receiver type to a call, we need to revisit
1543 // the Catch following the call. It's looking for a non-NULL
1544 // receiver to know when to enable the regular fall-through path
1545 // in addition to the NullPtrException path.
1546 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1547 Node* p = use->as_CallDynamicJava()->proj_out_or_null(TypeFunc::Control);
1548 if (p != NULL) {
1549 add_users_to_worklist0(p);
1550 }
1551 }
1552
1553 uint use_op = use->Opcode();
1554 if(use->is_Cmp()) { // Enable CMP/BOOL optimization
1555 add_users_to_worklist(use); // Put Bool on worklist
1556 if (use->outcnt() > 0) {
1557 Node* bol = use->raw_out(0);
1558 if (bol->outcnt() > 0) {
1559 Node* iff = bol->raw_out(0);
1560 if (iff->outcnt() == 2) {
1561 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1562 // phi merging either 0 or 1 onto the worklist
1563 Node* ifproj0 = iff->raw_out(0);
1564 Node* ifproj1 = iff->raw_out(1);
1565 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1566 Node* region0 = ifproj0->raw_out(0);
1567 Node* region1 = ifproj1->raw_out(0);
1568 if( region0 == region1 )
1569 add_users_to_worklist0(region0);
1570 }
1571 }
1572 }
1573 }
1574 if (use_op == Op_CmpI) {
1575 Node* phi = countedloop_phi_from_cmp((CmpINode*)use, n);
1576 if (phi != NULL) {
1577 // If an opaque node feeds into the limit condition of a
1578 // CountedLoop, we need to process the Phi node for the
1579 // induction variable when the opaque node is removed:
1580 // the range of values taken by the Phi is now known and
1581 // so its type is also known.
1582 _worklist.push(phi);
1583 }
1584 Node* in1 = use->in(1);
1585 for (uint i = 0; i < in1->outcnt(); i++) {
1586 if (in1->raw_out(i)->Opcode() == Op_CastII) {
1587 Node* castii = in1->raw_out(i);
1588 if (castii->in(0) != NULL && castii->in(0)->in(0) != NULL && castii->in(0)->in(0)->is_If()) {
1589 Node* ifnode = castii->in(0)->in(0);
1590 if (ifnode->in(1) != NULL && ifnode->in(1)->is_Bool() && ifnode->in(1)->in(1) == use) {
1591 // Reprocess a CastII node that may depend on an
1592 // opaque node value when the opaque node is
1593 // removed. In case it carries a dependency we can do
1594 // a better job of computing its type.
1595 _worklist.push(castii);
1596 }
1597 }
1598 }
1599 }
1600 }
1601 }
1602
1603 // If changed Cast input, check Phi users for simple cycles
1604 if (use->is_ConstraintCast()) {
1605 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1606 Node* u = use->fast_out(i2);
1607 if (u->is_Phi())
1608 _worklist.push(u);
1609 }
1610 }
1611 // If changed LShift inputs, check RShift users for useless sign-ext
1612 if( use_op == Op_LShiftI ) {
1613 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1614 Node* u = use->fast_out(i2);
1615 if (u->Opcode() == Op_RShiftI)
1616 _worklist.push(u);
1617 }
1618 }
1619 // If changed AddI/SubI inputs, check CmpU for range check optimization.
1620 if (use_op == Op_AddI || use_op == Op_SubI) {
1621 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1622 Node* u = use->fast_out(i2);
1623 if (u->is_Cmp() && (u->Opcode() == Op_CmpU)) {
1624 _worklist.push(u);
1625 }
1626 }
1627 }
1628 // If changed AddP inputs, check Stores for loop invariant
1629 if( use_op == Op_AddP ) {
1630 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1631 Node* u = use->fast_out(i2);
1632 if (u->is_Mem())
1633 _worklist.push(u);
1634 }
1635 }
1636 // If changed initialization activity, check dependent Stores
1637 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1638 InitializeNode* init = use->as_Allocate()->initialization();
1639 if (init != NULL) {
1640 Node* imem = init->proj_out_or_null(TypeFunc::Memory);
1641 if (imem != NULL) add_users_to_worklist0(imem);
1642 }
1643 }
1644 if (use_op == Op_Initialize) {
1645 Node* imem = use->as_Initialize()->proj_out_or_null(TypeFunc::Memory);
1646 if (imem != NULL) add_users_to_worklist0(imem);
1647 }
1648 // Loading the java mirror from a Klass requires two loads and the type
1649 // of the mirror load depends on the type of 'n'. See LoadNode::Value().
1650 // LoadBarrier?(LoadP(LoadP(AddP(foo:Klass, #java_mirror))))
1651 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1652 bool has_load_barriers = bs->has_load_barriers();
1653
1654 if (use_op == Op_LoadP && use->bottom_type()->isa_rawptr()) {
1655 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1656 Node* u = use->fast_out(i2);
1657 const Type* ut = u->bottom_type();
1658 if (u->Opcode() == Op_LoadP && ut->isa_instptr()) {
1659 if (has_load_barriers) {
1660 // Search for load barriers behind the load
1661 for (DUIterator_Fast i3max, i3 = u->fast_outs(i3max); i3 < i3max; i3++) {
1662 Node* b = u->fast_out(i3);
1663 if (bs->is_gc_barrier_node(b)) {
1664 _worklist.push(b);
1665 }
1666 }
1667 }
1668 _worklist.push(u);
1669 }
1670 }
1671 }
1672
1673 BarrierSet::barrier_set()->barrier_set_c2()->igvn_add_users_to_worklist(this, use);
1674 }
1675 }
1676
1677 /**
1678 * Remove the speculative part of all types that we know of
1679 */
1680 void PhaseIterGVN::remove_speculative_types() {
1681 assert(UseTypeSpeculation, "speculation is off");
1682 for (uint i = 0; i < _types.Size(); i++) {
1683 const Type* t = _types.fast_lookup(i);
1684 if (t != NULL) {
1685 _types.map(i, t->remove_speculative());
1686 }
1687 }
1688 _table.check_no_speculative_types();
1689 }
1690
1691 //=============================================================================
1692 #ifndef PRODUCT
1693 uint PhaseCCP::_total_invokes = 0;
1694 uint PhaseCCP::_total_constants = 0;
1695 #endif
1696 //------------------------------PhaseCCP---------------------------------------
1697 // Conditional Constant Propagation, ala Wegman & Zadeck
1698 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1699 NOT_PRODUCT( clear_constants(); )
1700 assert( _worklist.size() == 0, "" );
1701 // Clear out _nodes from IterGVN. Must be clear to transform call.
1702 _nodes.clear(); // Clear out from IterGVN
1703 analyze();
1704 }
1705
1706 #ifndef PRODUCT
1707 //------------------------------~PhaseCCP--------------------------------------
1708 PhaseCCP::~PhaseCCP() {
1709 inc_invokes();
1710 _total_constants += count_constants();
1711 }
1712 #endif
1713
1714
1715 #ifdef ASSERT
1716 static bool ccp_type_widens(const Type* t, const Type* t0) {
1717 assert(t->meet(t0) == t, "Not monotonic");
1718 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1719 case Type::Int:
1720 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1721 break;
1722 case Type::Long:
1723 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1724 break;
1725 default:
1726 break;
1727 }
1728 return true;
1729 }
1730 #endif //ASSERT
1731
1732 //------------------------------analyze----------------------------------------
1733 void PhaseCCP::analyze() {
1734 // Initialize all types to TOP, optimistic analysis
1735 for (int i = C->unique() - 1; i >= 0; i--) {
1736 _types.map(i,Type::TOP);
1737 }
1738
1739 // Push root onto worklist
1740 Unique_Node_List worklist;
1741 worklist.push(C->root());
1742
1743 // Pull from worklist; compute new value; push changes out.
1744 // This loop is the meat of CCP.
1745 while( worklist.size() ) {
1746 Node *n = worklist.pop();
1747 const Type *t = n->Value(this);
1748 if (t != type(n)) {
1749 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1750 #ifndef PRODUCT
1751 if( TracePhaseCCP ) {
1752 t->dump();
1753 do { tty->print("\t"); } while (tty->position() < 16);
1754 n->dump();
1755 }
1756 #endif
1757 set_type(n, t);
1758 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1759 Node* m = n->fast_out(i); // Get user
1760 if (m->is_Region()) { // New path to Region? Must recheck Phis too
1761 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1762 Node* p = m->fast_out(i2); // Propagate changes to uses
1763 if (p->bottom_type() != type(p)) { // If not already bottomed out
1764 worklist.push(p); // Propagate change to user
1765 }
1766 }
1767 }
1768 // If we changed the receiver type to a call, we need to revisit
1769 // the Catch following the call. It's looking for a non-NULL
1770 // receiver to know when to enable the regular fall-through path
1771 // in addition to the NullPtrException path
1772 if (m->is_Call()) {
1773 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1774 Node* p = m->fast_out(i2); // Propagate changes to uses
1775 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1) {
1776 worklist.push(p->unique_out());
1777 }
1778 }
1779 }
1780 if (m->bottom_type() != type(m)) { // If not already bottomed out
1781 worklist.push(m); // Propagate change to user
1782 }
1783
1784 // CmpU nodes can get their type information from two nodes up in the
1785 // graph (instead of from the nodes immediately above). Make sure they
1786 // are added to the worklist if nodes they depend on are updated, since
1787 // they could be missed and get wrong types otherwise.
1788 uint m_op = m->Opcode();
1789 if (m_op == Op_AddI || m_op == Op_SubI) {
1790 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1791 Node* p = m->fast_out(i2); // Propagate changes to uses
1792 if (p->Opcode() == Op_CmpU) {
1793 // Got a CmpU which might need the new type information from node n.
1794 if(p->bottom_type() != type(p)) { // If not already bottomed out
1795 worklist.push(p); // Propagate change to user
1796 }
1797 }
1798 }
1799 }
1800 // If n is used in a counted loop exit condition then the type
1801 // of the counted loop's Phi depends on the type of n. See
1802 // PhiNode::Value().
1803 if (m_op == Op_CmpI) {
1804 PhiNode* phi = countedloop_phi_from_cmp((CmpINode*)m, n);
1805 if (phi != NULL) {
1806 worklist.push(phi);
1807 }
1808 }
1809 // Loading the java mirror from a Klass requires two loads and the type
1810 // of the mirror load depends on the type of 'n'. See LoadNode::Value().
1811 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1812 bool has_load_barriers = bs->has_load_barriers();
1813
1814 if (m_op == Op_LoadP && m->bottom_type()->isa_rawptr()) {
1815 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1816 Node* u = m->fast_out(i2);
1817 const Type* ut = u->bottom_type();
1818 if (u->Opcode() == Op_LoadP && ut->isa_instptr() && ut != type(u)) {
1819 if (has_load_barriers) {
1820 // Search for load barriers behind the load
1821 for (DUIterator_Fast i3max, i3 = u->fast_outs(i3max); i3 < i3max; i3++) {
1822 Node* b = u->fast_out(i3);
1823 if (bs->is_gc_barrier_node(b)) {
1824 worklist.push(b);
1825 }
1826 }
1827 }
1828 worklist.push(u);
1829 }
1830 }
1831 }
1832
1833 BarrierSet::barrier_set()->barrier_set_c2()->ccp_analyze(this, worklist, m);
1834 }
1835 }
1836 }
1837 }
1838
1839 //------------------------------do_transform-----------------------------------
1840 // Top level driver for the recursive transformer
1841 void PhaseCCP::do_transform() {
1842 // Correct leaves of new-space Nodes; they point to old-space.
1843 C->set_root( transform(C->root())->as_Root() );
1844 assert( C->top(), "missing TOP node" );
1845 assert( C->root(), "missing root" );
1846 }
1847
1848 //------------------------------transform--------------------------------------
1849 // Given a Node in old-space, clone him into new-space.
1850 // Convert any of his old-space children into new-space children.
1851 Node *PhaseCCP::transform( Node *n ) {
1852 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1853 if( new_node != NULL )
1854 return new_node; // Been there, done that, return old answer
1855 new_node = transform_once(n); // Check for constant
1856 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1857
1858 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1859 GrowableArray <Node *> trstack(C->live_nodes() >> 1);
1860
1861 trstack.push(new_node); // Process children of cloned node
1862 while ( trstack.is_nonempty() ) {
1863 Node *clone = trstack.pop();
1864 uint cnt = clone->req();
1865 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1866 Node *input = clone->in(i);
1867 if( input != NULL ) { // Ignore NULLs
1868 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1869 if( new_input == NULL ) {
1870 new_input = transform_once(input); // Check for constant
1871 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1872 trstack.push(new_input);
1873 }
1874 assert( new_input == clone->in(i), "insanity check");
1875 }
1876 }
1877 }
1878 return new_node;
1879 }
1880
1881
1882 //------------------------------transform_once---------------------------------
1883 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1884 Node *PhaseCCP::transform_once( Node *n ) {
1885 const Type *t = type(n);
1886 // Constant? Use constant Node instead
1887 if( t->singleton() ) {
1888 Node *nn = n; // Default is to return the original constant
1889 if( t == Type::TOP ) {
1890 // cache my top node on the Compile instance
1891 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1892 C->set_cached_top_node(ConNode::make(Type::TOP));
1893 set_type(C->top(), Type::TOP);
1894 }
1895 nn = C->top();
1896 }
1897 if( !n->is_Con() ) {
1898 if( t != Type::TOP ) {
1899 nn = makecon(t); // ConNode::make(t);
1900 NOT_PRODUCT( inc_constants(); )
1901 } else if( n->is_Region() ) { // Unreachable region
1902 // Note: nn == C->top()
1903 n->set_req(0, NULL); // Cut selfreference
1904 bool progress = true;
1905 uint max = n->outcnt();
1906 DUIterator i;
1907 while (progress) {
1908 progress = false;
1909 // Eagerly remove dead phis to avoid phis copies creation.
1910 for (i = n->outs(); n->has_out(i); i++) {
1911 Node* m = n->out(i);
1912 if (m->is_Phi()) {
1913 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1914 replace_node(m, nn);
1915 if (max != n->outcnt()) {
1916 progress = true;
1917 i = n->refresh_out_pos(i);
1918 max = n->outcnt();
1919 }
1920 }
1921 }
1922 }
1923 }
1924 replace_node(n,nn); // Update DefUse edges for new constant
1925 }
1926 return nn;
1927 }
1928
1929 // If x is a TypeNode, capture any more-precise type permanently into Node
1930 if (t != n->bottom_type()) {
1931 hash_delete(n); // changing bottom type may force a rehash
1932 n->raise_bottom_type(t);
1933 _worklist.push(n); // n re-enters the hash table via the worklist
1934 }
1935
1936 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1937 switch( n->Opcode() ) {
1938 case Op_FastLock: // Revisit FastLocks for lock coarsening
1939 case Op_If:
1940 case Op_CountedLoopEnd:
1941 case Op_Region:
1942 case Op_Loop:
1943 case Op_CountedLoop:
1944 case Op_Conv2B:
1945 case Op_Opaque1:
1946 case Op_Opaque2:
1947 _worklist.push(n);
1948 break;
1949 default:
1950 break;
1951 }
1952
1953 return n;
1954 }
1955
1956 //---------------------------------saturate------------------------------------
1957 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1958 const Type* limit_type) const {
1959 const Type* wide_type = new_type->widen(old_type, limit_type);
1960 if (wide_type != new_type) { // did we widen?
1961 // If so, we may have widened beyond the limit type. Clip it back down.
1962 new_type = wide_type->filter(limit_type);
1963 }
1964 return new_type;
1965 }
1966
1967 //------------------------------print_statistics-------------------------------
1968 #ifndef PRODUCT
1969 void PhaseCCP::print_statistics() {
1970 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1971 }
1972 #endif
1973
1974
1975 //=============================================================================
1976 #ifndef PRODUCT
1977 uint PhasePeephole::_total_peepholes = 0;
1978 #endif
1979 //------------------------------PhasePeephole----------------------------------
1980 // Conditional Constant Propagation, ala Wegman & Zadeck
1981 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1982 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1983 NOT_PRODUCT( clear_peepholes(); )
1984 }
1985
1986 #ifndef PRODUCT
1987 //------------------------------~PhasePeephole---------------------------------
1988 PhasePeephole::~PhasePeephole() {
1989 _total_peepholes += count_peepholes();
1990 }
1991 #endif
1992
1993 //------------------------------transform--------------------------------------
1994 Node *PhasePeephole::transform( Node *n ) {
1995 ShouldNotCallThis();
1996 return NULL;
1997 }
1998
1999 //------------------------------do_transform-----------------------------------
2000 void PhasePeephole::do_transform() {
2001 bool method_name_not_printed = true;
2002
2003 // Examine each basic block
2004 for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) {
2005 Block* block = _cfg.get_block(block_number);
2006 bool block_not_printed = true;
2007
2008 // and each instruction within a block
2009 uint end_index = block->number_of_nodes();
2010 // block->end_idx() not valid after PhaseRegAlloc
2011 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
2012 Node *n = block->get_node(instruction_index);
2013 if( n->is_Mach() ) {
2014 MachNode *m = n->as_Mach();
2015 int deleted_count = 0;
2016 // check for peephole opportunities
2017 MachNode *m2 = m->peephole(block, instruction_index, _regalloc, deleted_count);
2018 if( m2 != NULL ) {
2019 #ifndef PRODUCT
2020 if( PrintOptoPeephole ) {
2021 // Print method, first time only
2022 if( C->method() && method_name_not_printed ) {
2023 C->method()->print_short_name(); tty->cr();
2024 method_name_not_printed = false;
2025 }
2026 // Print this block
2027 if( Verbose && block_not_printed) {
2028 tty->print_cr("in block");
2029 block->dump();
2030 block_not_printed = false;
2031 }
2032 // Print instructions being deleted
2033 for( int i = (deleted_count - 1); i >= 0; --i ) {
2034 block->get_node(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
2035 }
2036 tty->print_cr("replaced with");
2037 // Print new instruction
2038 m2->format(_regalloc);
2039 tty->print("\n\n");
2040 }
2041 #endif
2042 // Remove old nodes from basic block and update instruction_index
2043 // (old nodes still exist and may have edges pointing to them
2044 // as register allocation info is stored in the allocator using
2045 // the node index to live range mappings.)
2046 uint safe_instruction_index = (instruction_index - deleted_count);
2047 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
2048 block->remove_node( instruction_index );
2049 }
2050 // install new node after safe_instruction_index
2051 block->insert_node(m2, safe_instruction_index + 1);
2052 end_index = block->number_of_nodes() - 1; // Recompute new block size
2053 NOT_PRODUCT( inc_peepholes(); )
2054 }
2055 }
2056 }
2057 }
2058 }
2059
2060 //------------------------------print_statistics-------------------------------
2061 #ifndef PRODUCT
2062 void PhasePeephole::print_statistics() {
2063 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
2064 }
2065 #endif
2066
2067
2068 //=============================================================================
2069 //------------------------------set_req_X--------------------------------------
2070 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
2071 assert( is_not_dead(n), "can not use dead node");
2072 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
2073 Node *old = in(i);
2074 set_req(i, n);
2075
2076 // old goes dead?
2077 if( old ) {
2078 switch (old->outcnt()) {
2079 case 0:
2080 // Put into the worklist to kill later. We do not kill it now because the
2081 // recursive kill will delete the current node (this) if dead-loop exists
2082 if (!old->is_top())
2083 igvn->_worklist.push( old );
2084 break;
2085 case 1:
2086 if( old->is_Store() || old->has_special_unique_user() )
2087 igvn->add_users_to_worklist( old );
2088 break;
2089 case 2:
2090 if( old->is_Store() )
2091 igvn->add_users_to_worklist( old );
2092 if( old->Opcode() == Op_Region )
2093 igvn->_worklist.push(old);
2094 break;
2095 case 3:
2096 if( old->Opcode() == Op_Region ) {
2097 igvn->_worklist.push(old);
2098 igvn->add_users_to_worklist( old );
2099 }
2100 break;
2101 default:
2102 break;
2103 }
2104
2105 BarrierSet::barrier_set()->barrier_set_c2()->enqueue_useful_gc_barrier(igvn, old);
2106 }
2107
2108 }
2109
2110 //-------------------------------replace_by-----------------------------------
2111 // Using def-use info, replace one node for another. Follow the def-use info
2112 // to all users of the OLD node. Then make all uses point to the NEW node.
2113 void Node::replace_by(Node *new_node) {
2114 assert(!is_top(), "top node has no DU info");
2115 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
2116 Node* use = last_out(i);
2117 uint uses_found = 0;
2118 for (uint j = 0; j < use->len(); j++) {
2119 if (use->in(j) == this) {
2120 if (j < use->req())
2121 use->set_req(j, new_node);
2122 else use->set_prec(j, new_node);
2123 uses_found++;
2124 }
2125 }
2126 i -= uses_found; // we deleted 1 or more copies of this edge
2127 }
2128 }
2129
2130 //=============================================================================
2131 //-----------------------------------------------------------------------------
2132 void Type_Array::grow( uint i ) {
2133 if( !_max ) {
2134 _max = 1;
2135 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
2136 _types[0] = NULL;
2137 }
2138 uint old = _max;
2139 while( i >= _max ) _max <<= 1; // Double to fit
2140 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
2141 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
2142 }
2143
2144 //------------------------------dump-------------------------------------------
2145 #ifndef PRODUCT
2146 void Type_Array::dump() const {
2147 uint max = Size();
2148 for( uint i = 0; i < max; i++ ) {
2149 if( _types[i] != NULL ) {
2150 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
2151 }
2152 }
2153 }
2154 #endif