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