1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "opto/block.hpp"
28 #include "opto/callnode.hpp"
29 #include "opto/cfgnode.hpp"
30 #include "opto/idealGraphPrinter.hpp"
31 #include "opto/loopnode.hpp"
32 #include "opto/machnode.hpp"
33 #include "opto/opcodes.hpp"
34 #include "opto/phaseX.hpp"
35 #include "opto/regalloc.hpp"
36 #include "opto/rootnode.hpp"
37
38 //=============================================================================
39 #define NODE_HASH_MINIMUM_SIZE 255
40 //------------------------------NodeHash---------------------------------------
41 NodeHash::NodeHash(uint est_max_size) :
42 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
43 _a(Thread::current()->resource_area()),
44 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ),
45 _inserts(0), _insert_limit( insert_limit() )
46 #ifndef PRODUCT
47 ,_look_probes(0), _lookup_hits(0), _lookup_misses(0),
48 _delete_probes(0), _delete_hits(0), _delete_misses(0),
49 _total_insert_probes(0), _total_inserts(0),
50 _insert_probes(0), _grows(0)
51 #endif
52 {
53 // _sentinel must be in the current node space
54 _sentinel = new ProjNode(NULL, TypeFunc::Control);
55 memset(_table,0,sizeof(Node*)*_max);
56 }
57
58 //------------------------------NodeHash---------------------------------------
59 NodeHash::NodeHash(Arena *arena, uint est_max_size) :
60 _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
61 _a(arena),
62 _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ),
63 _inserts(0), _insert_limit( insert_limit() )
64 #ifndef PRODUCT
65 ,_look_probes(0), _lookup_hits(0), _lookup_misses(0),
66 _delete_probes(0), _delete_hits(0), _delete_misses(0),
67 _total_insert_probes(0), _total_inserts(0),
68 _insert_probes(0), _grows(0)
69 #endif
70 {
71 // _sentinel must be in the current node space
72 _sentinel = new ProjNode(NULL, TypeFunc::Control);
73 memset(_table,0,sizeof(Node*)*_max);
74 }
75
76 //------------------------------NodeHash---------------------------------------
77 NodeHash::NodeHash(NodeHash *nh) {
78 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
79 // just copy in all the fields
80 *this = *nh;
81 // nh->_sentinel must be in the current node space
82 }
83
84 void NodeHash::replace_with(NodeHash *nh) {
85 debug_only(_table = (Node**)badAddress); // interact correctly w/ operator=
86 // just copy in all the fields
87 *this = *nh;
88 // nh->_sentinel must be in the current node space
89 }
90
91 //------------------------------hash_find--------------------------------------
92 // Find in hash table
93 Node *NodeHash::hash_find( const Node *n ) {
94 // ((Node*)n)->set_hash( n->hash() );
95 uint hash = n->hash();
96 if (hash == Node::NO_HASH) {
97 NOT_PRODUCT( _lookup_misses++ );
98 return NULL;
99 }
100 uint key = hash & (_max-1);
101 uint stride = key | 0x01;
102 NOT_PRODUCT( _look_probes++ );
103 Node *k = _table[key]; // Get hashed value
104 if( !k ) { // ?Miss?
105 NOT_PRODUCT( _lookup_misses++ );
106 return NULL; // Miss!
107 }
108
109 int op = n->Opcode();
110 uint req = n->req();
111 while( 1 ) { // While probing hash table
112 if( k->req() == req && // Same count of inputs
113 k->Opcode() == op ) { // Same Opcode
114 for( uint i=0; i<req; i++ )
115 if( n->in(i)!=k->in(i)) // Different inputs?
116 goto collision; // "goto" is a speed hack...
117 if( n->cmp(*k) ) { // Check for any special bits
118 NOT_PRODUCT( _lookup_hits++ );
119 return k; // Hit!
120 }
121 }
122 collision:
123 NOT_PRODUCT( _look_probes++ );
124 key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime
125 k = _table[key]; // Get hashed value
126 if( !k ) { // ?Miss?
127 NOT_PRODUCT( _lookup_misses++ );
128 return NULL; // Miss!
129 }
130 }
131 ShouldNotReachHere();
132 return NULL;
133 }
134
135 //------------------------------hash_find_insert-------------------------------
136 // Find in hash table, insert if not already present
137 // Used to preserve unique entries in hash table
138 Node *NodeHash::hash_find_insert( Node *n ) {
139 // n->set_hash( );
140 uint hash = n->hash();
141 if (hash == Node::NO_HASH) {
142 NOT_PRODUCT( _lookup_misses++ );
143 return NULL;
144 }
145 uint key = hash & (_max-1);
146 uint stride = key | 0x01; // stride must be relatively prime to table siz
147 uint first_sentinel = 0; // replace a sentinel if seen.
148 NOT_PRODUCT( _look_probes++ );
149 Node *k = _table[key]; // Get hashed value
150 if( !k ) { // ?Miss?
151 NOT_PRODUCT( _lookup_misses++ );
152 _table[key] = n; // Insert into table!
153 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
154 check_grow(); // Grow table if insert hit limit
155 return NULL; // Miss!
156 }
157 else if( k == _sentinel ) {
158 first_sentinel = key; // Can insert here
159 }
160
161 int op = n->Opcode();
162 uint req = n->req();
163 while( 1 ) { // While probing hash table
164 if( k->req() == req && // Same count of inputs
165 k->Opcode() == op ) { // Same Opcode
166 for( uint i=0; i<req; i++ )
167 if( n->in(i)!=k->in(i)) // Different inputs?
168 goto collision; // "goto" is a speed hack...
169 if( n->cmp(*k) ) { // Check for any special bits
170 NOT_PRODUCT( _lookup_hits++ );
171 return k; // Hit!
172 }
173 }
174 collision:
175 NOT_PRODUCT( _look_probes++ );
176 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
177 k = _table[key]; // Get hashed value
178 if( !k ) { // ?Miss?
179 NOT_PRODUCT( _lookup_misses++ );
180 key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel?
181 _table[key] = n; // Insert into table!
182 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
183 check_grow(); // Grow table if insert hit limit
184 return NULL; // Miss!
185 }
186 else if( first_sentinel == 0 && k == _sentinel ) {
187 first_sentinel = key; // Can insert here
188 }
189
190 }
191 ShouldNotReachHere();
192 return NULL;
193 }
194
195 //------------------------------hash_insert------------------------------------
196 // Insert into hash table
197 void NodeHash::hash_insert( Node *n ) {
198 // // "conflict" comments -- print nodes that conflict
199 // bool conflict = false;
200 // n->set_hash();
201 uint hash = n->hash();
202 if (hash == Node::NO_HASH) {
203 return;
204 }
205 check_grow();
206 uint key = hash & (_max-1);
207 uint stride = key | 0x01;
208
209 while( 1 ) { // While probing hash table
210 NOT_PRODUCT( _insert_probes++ );
211 Node *k = _table[key]; // Get hashed value
212 if( !k || (k == _sentinel) ) break; // Found a slot
213 assert( k != n, "already inserted" );
214 // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print(" conflict: "); k->dump(); conflict = true; }
215 key = (key + stride) & (_max-1); // Stride through table w/ relative prime
216 }
217 _table[key] = n; // Insert into table!
218 debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
219 // if( conflict ) { n->dump(); }
220 }
221
222 //------------------------------hash_delete------------------------------------
223 // Replace in hash table with sentinel
224 bool NodeHash::hash_delete( const Node *n ) {
225 Node *k;
226 uint hash = n->hash();
227 if (hash == Node::NO_HASH) {
228 NOT_PRODUCT( _delete_misses++ );
229 return false;
230 }
231 uint key = hash & (_max-1);
232 uint stride = key | 0x01;
233 debug_only( uint counter = 0; );
234 for( ; /* (k != NULL) && (k != _sentinel) */; ) {
235 debug_only( counter++ );
236 NOT_PRODUCT( _delete_probes++ );
237 k = _table[key]; // Get hashed value
238 if( !k ) { // Miss?
239 NOT_PRODUCT( _delete_misses++ );
240 #ifdef ASSERT
241 if( VerifyOpto ) {
242 for( uint i=0; i < _max; i++ )
243 assert( _table[i] != n, "changed edges with rehashing" );
244 }
245 #endif
246 return false; // Miss! Not in chain
247 }
248 else if( n == k ) {
249 NOT_PRODUCT( _delete_hits++ );
250 _table[key] = _sentinel; // Hit! Label as deleted entry
251 debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table.
252 return true;
253 }
254 else {
255 // collision: move through table with prime offset
256 key = (key + stride/*7*/) & (_max-1);
257 assert( counter <= _insert_limit, "Cycle in hash-table");
258 }
259 }
260 ShouldNotReachHere();
261 return false;
262 }
263
264 //------------------------------round_up---------------------------------------
265 // Round up to nearest power of 2
266 uint NodeHash::round_up( uint x ) {
267 x += (x>>2); // Add 25% slop
268 if( x <16 ) return 16; // Small stuff
269 uint i=16;
270 while( i < x ) i <<= 1; // Double to fit
271 return i; // Return hash table size
272 }
273
274 //------------------------------grow-------------------------------------------
275 // Grow _table to next power of 2 and insert old entries
276 void NodeHash::grow() {
277 // Record old state
278 uint old_max = _max;
279 Node **old_table = _table;
280 // Construct new table with twice the space
281 #ifndef PRODUCT
282 _grows++;
283 _total_inserts += _inserts;
284 _total_insert_probes += _insert_probes;
285 _insert_probes = 0;
286 #endif
287 _inserts = 0;
288 _max = _max << 1;
289 _table = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) );
290 memset(_table,0,sizeof(Node*)*_max);
291 _insert_limit = insert_limit();
292 // Insert old entries into the new table
293 for( uint i = 0; i < old_max; i++ ) {
294 Node *m = *old_table++;
295 if( !m || m == _sentinel ) continue;
296 debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table.
297 hash_insert(m);
298 }
299 }
300
301 //------------------------------clear------------------------------------------
302 // Clear all entries in _table to NULL but keep storage
303 void NodeHash::clear() {
304 #ifdef ASSERT
305 // Unlock all nodes upon removal from table.
306 for (uint i = 0; i < _max; i++) {
307 Node* n = _table[i];
308 if (!n || n == _sentinel) continue;
309 n->exit_hash_lock();
310 }
311 #endif
312
313 memset( _table, 0, _max * sizeof(Node*) );
314 }
315
316 //-----------------------remove_useless_nodes----------------------------------
317 // Remove useless nodes from value table,
318 // implementation does not depend on hash function
319 void NodeHash::remove_useless_nodes(VectorSet &useful) {
320
321 // Dead nodes in the hash table inherited from GVN should not replace
322 // existing nodes, remove dead nodes.
323 uint max = size();
324 Node *sentinel_node = sentinel();
325 for( uint i = 0; i < max; ++i ) {
326 Node *n = at(i);
327 if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) {
328 debug_only(n->exit_hash_lock()); // Unlock the node when removed
329 _table[i] = sentinel_node; // Replace with placeholder
330 }
331 }
332 }
333
334
335 void NodeHash::check_no_speculative_types() {
336 #ifdef ASSERT
337 uint max = size();
338 Node *sentinel_node = sentinel();
339 for (uint i = 0; i < max; ++i) {
340 Node *n = at(i);
341 if(n != NULL && n != sentinel_node && n->is_Type() && n->outcnt() > 0) {
342 TypeNode* tn = n->as_Type();
343 const Type* t = tn->type();
344 const Type* t_no_spec = t->remove_speculative();
345 assert(t == t_no_spec, "dead node in hash table or missed node during speculative cleanup");
346 }
347 }
348 #endif
349 }
350
351 #ifndef PRODUCT
352 //------------------------------dump-------------------------------------------
353 // Dump statistics for the hash table
354 void NodeHash::dump() {
355 _total_inserts += _inserts;
356 _total_insert_probes += _insert_probes;
357 if (PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0)) {
358 if (WizardMode) {
359 for (uint i=0; i<_max; i++) {
360 if (_table[i])
361 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
362 }
363 }
364 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max);
365 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
366 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
367 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
368 // sentinels increase lookup cost, but not insert cost
369 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
370 assert( _inserts+(_inserts>>3) < _max, "table too full" );
371 assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
372 }
373 }
374
375 Node *NodeHash::find_index(uint idx) { // For debugging
376 // Find an entry by its index value
377 for( uint i = 0; i < _max; i++ ) {
378 Node *m = _table[i];
379 if( !m || m == _sentinel ) continue;
380 if( m->_idx == (uint)idx ) return m;
381 }
382 return NULL;
383 }
384 #endif
385
386 #ifdef ASSERT
387 NodeHash::~NodeHash() {
388 // Unlock all nodes upon destruction of table.
389 if (_table != (Node**)badAddress) clear();
390 }
391
392 void NodeHash::operator=(const NodeHash& nh) {
393 // Unlock all nodes upon replacement of table.
394 if (&nh == this) return;
395 if (_table != (Node**)badAddress) clear();
396 memcpy(this, &nh, sizeof(*this));
397 // Do not increment hash_lock counts again.
398 // Instead, be sure we never again use the source table.
399 ((NodeHash*)&nh)->_table = (Node**)badAddress;
400 }
401
402
403 #endif
404
405
406 //=============================================================================
407 //------------------------------PhaseRemoveUseless-----------------------------
408 // 1) Use a breadthfirst walk to collect useful nodes reachable from root.
409 PhaseRemoveUseless::PhaseRemoveUseless(PhaseGVN *gvn, Unique_Node_List *worklist, PhaseNumber phase_num) : Phase(phase_num),
410 _useful(Thread::current()->resource_area()) {
411
412 // Implementation requires 'UseLoopSafepoints == true' and an edge from root
413 // to each SafePointNode at a backward branch. Inserted in add_safepoint().
414 if( !UseLoopSafepoints || !OptoRemoveUseless ) return;
415
416 // Identify nodes that are reachable from below, useful.
417 C->identify_useful_nodes(_useful);
418 // Update dead node list
419 C->update_dead_node_list(_useful);
420
421 // Remove all useless nodes from PhaseValues' recorded types
422 // Must be done before disconnecting nodes to preserve hash-table-invariant
423 gvn->remove_useless_nodes(_useful.member_set());
424
425 // Remove all useless nodes from future worklist
426 worklist->remove_useless_nodes(_useful.member_set());
427
428 // Disconnect 'useless' nodes that are adjacent to useful nodes
429 C->remove_useless_nodes(_useful);
430
431 // Remove edges from "root" to each SafePoint at a backward branch.
432 // They were inserted during parsing (see add_safepoint()) to make infinite
433 // loops without calls or exceptions visible to root, i.e., useful.
434 Node *root = C->root();
435 if( root != NULL ) {
436 for( uint i = root->req(); i < root->len(); ++i ) {
437 Node *n = root->in(i);
438 if( n != NULL && n->is_SafePoint() ) {
439 root->rm_prec(i);
440 --i;
441 }
442 }
443 }
444 }
445
446 //=============================================================================
447 //------------------------------PhaseRenumberLive------------------------------
448 // First, remove useless nodes (equivalent to identifying live nodes).
449 // Then, renumber live nodes.
450 //
451 // The set of live nodes is returned by PhaseRemoveUseless in the _useful structure.
452 // If the number of live nodes is 'x' (where 'x' == _useful.size()), then the
453 // PhaseRenumberLive updates the node ID of each node (the _idx field) with a unique
454 // value in the range [0, x).
455 //
456 // At the end of the PhaseRenumberLive phase, the compiler's count of unique nodes is
457 // updated to 'x' and the list of dead nodes is reset (as there are no dead nodes).
458 //
459 // The PhaseRenumberLive phase updates two data structures with the new node IDs.
460 // (1) The worklist is used by the PhaseIterGVN phase to identify nodes that must be
461 // processed. A new worklist (with the updated node IDs) is returned in 'new_worklist'.
462 // (2) Type information (the field PhaseGVN::_types) maps type information to each
463 // node ID. The mapping is updated to use the new node IDs as well. Updated type
464 // information is returned in PhaseGVN::_types.
465 //
466 // The PhaseRenumberLive phase does not preserve the order of elements in the worklist.
467 //
468 // Other data structures used by the compiler are not updated. The hash table for value
469 // numbering (the field PhaseGVN::_table) is not updated because computing the hash
470 // values is not based on node IDs. The field PhaseGVN::_nodes is not updated either
471 // because it is empty wherever PhaseRenumberLive is used.
472 PhaseRenumberLive::PhaseRenumberLive(PhaseGVN* gvn,
473 Unique_Node_List* worklist, Unique_Node_List* new_worklist,
474 PhaseNumber phase_num) :
475 PhaseRemoveUseless(gvn, worklist, Remove_Useless_And_Renumber_Live) {
476
477 assert(RenumberLiveNodes, "RenumberLiveNodes must be set to true for node renumbering to take place");
478 assert(C->live_nodes() == _useful.size(), "the number of live nodes must match the number of useful nodes");
479 assert(gvn->nodes_size() == 0, "GVN must not contain any nodes at this point");
480
481 uint old_unique_count = C->unique();
482 uint live_node_count = C->live_nodes();
483 uint worklist_size = worklist->size();
484
485 // Storage for the updated type information.
486 Type_Array new_type_array(C->comp_arena());
487
488 // Iterate over the set of live nodes.
489 uint current_idx = 0; // The current new node ID. Incremented after every assignment.
490 for (uint i = 0; i < _useful.size(); i++) {
491 Node* n = _useful.at(i);
492 const Type* type = gvn->type_or_null(n);
493 new_type_array.map(current_idx, type);
494
495 bool in_worklist = false;
496 if (worklist->member(n)) {
497 in_worklist = true;
498 }
499
500 n->set_idx(current_idx); // Update node ID.
501
502 if (in_worklist) {
503 new_worklist->push(n);
504 }
505
506 current_idx++;
507 }
508
509 assert(worklist_size == new_worklist->size(), "the new worklist must have the same size as the original worklist");
510 assert(live_node_count == current_idx, "all live nodes must be processed");
511
512 // Replace the compiler's type information with the updated type information.
513 gvn->replace_types(new_type_array);
514
515 // Update the unique node count of the compilation to the number of currently live nodes.
516 C->set_unique(live_node_count);
517
518 // Set the dead node count to 0 and reset dead node list.
519 C->reset_dead_node_list();
520 }
521
522
523 //=============================================================================
524 //------------------------------PhaseTransform---------------------------------
525 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
526 _arena(Thread::current()->resource_area()),
527 _nodes(_arena),
528 _types(_arena)
529 {
530 init_con_caches();
531 #ifndef PRODUCT
532 clear_progress();
533 clear_transforms();
534 set_allow_progress(true);
535 #endif
536 // Force allocation for currently existing nodes
537 _types.map(C->unique(), NULL);
538 }
539
540 //------------------------------PhaseTransform---------------------------------
541 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
542 _arena(arena),
543 _nodes(arena),
544 _types(arena)
545 {
546 init_con_caches();
547 #ifndef PRODUCT
548 clear_progress();
549 clear_transforms();
550 set_allow_progress(true);
551 #endif
552 // Force allocation for currently existing nodes
553 _types.map(C->unique(), NULL);
554 }
555
556 //------------------------------PhaseTransform---------------------------------
557 // Initialize with previously generated type information
558 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
559 _arena(pt->_arena),
560 _nodes(pt->_nodes),
561 _types(pt->_types)
562 {
563 init_con_caches();
564 #ifndef PRODUCT
565 clear_progress();
566 clear_transforms();
567 set_allow_progress(true);
568 #endif
569 }
570
571 void PhaseTransform::init_con_caches() {
572 memset(_icons,0,sizeof(_icons));
573 memset(_lcons,0,sizeof(_lcons));
574 memset(_zcons,0,sizeof(_zcons));
575 }
576
577
578 //--------------------------------find_int_type--------------------------------
579 const TypeInt* PhaseTransform::find_int_type(Node* n) {
580 if (n == NULL) return NULL;
581 // Call type_or_null(n) to determine node's type since we might be in
582 // parse phase and call n->Value() may return wrong type.
583 // (For example, a phi node at the beginning of loop parsing is not ready.)
584 const Type* t = type_or_null(n);
585 if (t == NULL) return NULL;
586 return t->isa_int();
587 }
588
589
590 //-------------------------------find_long_type--------------------------------
591 const TypeLong* PhaseTransform::find_long_type(Node* n) {
592 if (n == NULL) return NULL;
593 // (See comment above on type_or_null.)
594 const Type* t = type_or_null(n);
595 if (t == NULL) return NULL;
596 return t->isa_long();
597 }
598
599
600 #ifndef PRODUCT
601 void PhaseTransform::dump_old2new_map() const {
602 _nodes.dump();
603 }
604
605 void PhaseTransform::dump_new( uint nidx ) const {
606 for( uint i=0; i<_nodes.Size(); i++ )
607 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
608 _nodes[i]->dump();
609 tty->cr();
610 tty->print_cr("Old index= %d",i);
611 return;
612 }
613 tty->print_cr("Node %d not found in the new indices", nidx);
614 }
615
616 //------------------------------dump_types-------------------------------------
617 void PhaseTransform::dump_types( ) const {
618 _types.dump();
619 }
620
621 //------------------------------dump_nodes_and_types---------------------------
622 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
623 VectorSet visited(Thread::current()->resource_area());
624 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
625 }
626
627 //------------------------------dump_nodes_and_types_recur---------------------
628 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
629 if( !n ) return;
630 if( depth == 0 ) return;
631 if( visited.test_set(n->_idx) ) return;
632 for( uint i=0; i<n->len(); i++ ) {
633 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
634 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
635 }
636 n->dump();
637 if (type_or_null(n) != NULL) {
638 tty->print(" "); type(n)->dump(); tty->cr();
639 }
640 }
641
642 #endif
643
644
645 //=============================================================================
646 //------------------------------PhaseValues------------------------------------
647 // Set minimum table size to "255"
648 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
649 NOT_PRODUCT( clear_new_values(); )
650 }
651
652 //------------------------------PhaseValues------------------------------------
653 // Set minimum table size to "255"
654 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
655 _table(&ptv->_table) {
656 NOT_PRODUCT( clear_new_values(); )
657 }
658
659 //------------------------------PhaseValues------------------------------------
660 // Used by +VerifyOpto. Clear out hash table but copy _types array.
661 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
662 _table(ptv->arena(),ptv->_table.size()) {
663 NOT_PRODUCT( clear_new_values(); )
664 }
665
666 //------------------------------~PhaseValues-----------------------------------
667 #ifndef PRODUCT
668 PhaseValues::~PhaseValues() {
669 _table.dump();
670
671 // Statistics for value progress and efficiency
672 if( PrintCompilation && Verbose && WizardMode ) {
673 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
674 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
675 if( made_transforms() != 0 ) {
676 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
677 } else {
678 tty->cr();
679 }
680 }
681 }
682 #endif
683
684 //------------------------------makecon----------------------------------------
685 ConNode* PhaseTransform::makecon(const Type *t) {
686 assert(t->singleton(), "must be a constant");
687 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
688 switch (t->base()) { // fast paths
689 case Type::Half:
690 case Type::Top: return (ConNode*) C->top();
691 case Type::Int: return intcon( t->is_int()->get_con() );
692 case Type::Long: return longcon( t->is_long()->get_con() );
693 }
694 if (t->is_zero_type())
695 return zerocon(t->basic_type());
696 return uncached_makecon(t);
697 }
698
699 //--------------------------uncached_makecon-----------------------------------
700 // Make an idealized constant - one of ConINode, ConPNode, etc.
701 ConNode* PhaseValues::uncached_makecon(const Type *t) {
702 assert(t->singleton(), "must be a constant");
703 ConNode* x = ConNode::make(t);
704 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
705 if (k == NULL) {
706 set_type(x, t); // Missed, provide type mapping
707 GrowableArray<Node_Notes*>* nna = C->node_note_array();
708 if (nna != NULL) {
709 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
710 loc->clear(); // do not put debug info on constants
711 }
712 } else {
713 x->destruct(); // Hit, destroy duplicate constant
714 x = k; // use existing constant
715 }
716 return x;
717 }
718
719 //------------------------------intcon-----------------------------------------
720 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
721 ConINode* PhaseTransform::intcon(int i) {
722 // Small integer? Check cache! Check that cached node is not dead
723 if (i >= _icon_min && i <= _icon_max) {
724 ConINode* icon = _icons[i-_icon_min];
725 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
726 return icon;
727 }
728 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
729 assert(icon->is_Con(), "");
730 if (i >= _icon_min && i <= _icon_max)
731 _icons[i-_icon_min] = icon; // Cache small integers
732 return icon;
733 }
734
735 //------------------------------longcon----------------------------------------
736 // Fast long constant.
737 ConLNode* PhaseTransform::longcon(jlong l) {
738 // Small integer? Check cache! Check that cached node is not dead
739 if (l >= _lcon_min && l <= _lcon_max) {
740 ConLNode* lcon = _lcons[l-_lcon_min];
741 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
742 return lcon;
743 }
744 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
745 assert(lcon->is_Con(), "");
746 if (l >= _lcon_min && l <= _lcon_max)
747 _lcons[l-_lcon_min] = lcon; // Cache small integers
748 return lcon;
749 }
750
751 //------------------------------zerocon-----------------------------------------
752 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
753 ConNode* PhaseTransform::zerocon(BasicType bt) {
754 assert((uint)bt <= _zcon_max, "domain check");
755 ConNode* zcon = _zcons[bt];
756 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
757 return zcon;
758 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
759 _zcons[bt] = zcon;
760 return zcon;
761 }
762
763
764
765 //=============================================================================
766 //------------------------------transform--------------------------------------
767 // Return a node which computes the same function as this node, but in a
768 // faster or cheaper fashion.
769 Node *PhaseGVN::transform( Node *n ) {
770 return transform_no_reclaim(n);
771 }
772
773 //------------------------------transform--------------------------------------
774 // Return a node which computes the same function as this node, but
775 // in a faster or cheaper fashion.
776 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
777 NOT_PRODUCT( set_transforms(); )
778
779 // Apply the Ideal call in a loop until it no longer applies
780 Node *k = n;
781 NOT_PRODUCT( uint loop_count = 0; )
782 while( 1 ) {
783 Node *i = k->Ideal(this, /*can_reshape=*/false);
784 if( !i ) break;
785 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
786 k = i;
787 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
788 }
789 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
790
791
792 // If brand new node, make space in type array.
793 ensure_type_or_null(k);
794
795 // Since I just called 'Value' to compute the set of run-time values
796 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
797 // cache Value. Later requests for the local phase->type of this Node can
798 // use the cached Value instead of suffering with 'bottom_type'.
799 const Type *t = k->Value(this); // Get runtime Value set
800 assert(t != NULL, "value sanity");
801 if (type_or_null(k) != t) {
802 #ifndef PRODUCT
803 // Do not count initial visit to node as a transformation
804 if (type_or_null(k) == NULL) {
805 inc_new_values();
806 set_progress();
807 }
808 #endif
809 set_type(k, t);
810 // If k is a TypeNode, capture any more-precise type permanently into Node
811 k->raise_bottom_type(t);
812 }
813
814 if( t->singleton() && !k->is_Con() ) {
815 NOT_PRODUCT( set_progress(); )
816 return makecon(t); // Turn into a constant
817 }
818
819 // Now check for Identities
820 Node *i = k->Identity(this); // Look for a nearby replacement
821 if( i != k ) { // Found? Return replacement!
822 NOT_PRODUCT( set_progress(); )
823 return i;
824 }
825
826 // Global Value Numbering
827 i = hash_find_insert(k); // Insert if new
828 if( i && (i != k) ) {
829 // Return the pre-existing node
830 NOT_PRODUCT( set_progress(); )
831 return i;
832 }
833
834 // Return Idealized original
835 return k;
836 }
837
838 bool PhaseGVN::is_dominator_helper(Node *d, Node *n, bool linear_only) {
839 if (d->is_top() || n->is_top()) {
840 return false;
841 }
842 assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes");
843 int i = 0;
844 while (d != n) {
845 n = IfNode::up_one_dom(n, linear_only);
846 i++;
847 if (n == NULL || i >= 10) {
848 return false;
849 }
850 }
851 return true;
852 }
853
854 #ifdef ASSERT
855 //------------------------------dead_loop_check--------------------------------
856 // Check for a simple dead loop when a data node references itself directly
857 // or through an other data node excluding cons and phis.
858 void PhaseGVN::dead_loop_check( Node *n ) {
859 // Phi may reference itself in a loop
860 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
861 // Do 2 levels check and only data inputs.
862 bool no_dead_loop = true;
863 uint cnt = n->req();
864 for (uint i = 1; i < cnt && no_dead_loop; i++) {
865 Node *in = n->in(i);
866 if (in == n) {
867 no_dead_loop = false;
868 } else if (in != NULL && !in->is_dead_loop_safe()) {
869 uint icnt = in->req();
870 for (uint j = 1; j < icnt && no_dead_loop; j++) {
871 if (in->in(j) == n || in->in(j) == in)
872 no_dead_loop = false;
873 }
874 }
875 }
876 if (!no_dead_loop) n->dump(3);
877 assert(no_dead_loop, "dead loop detected");
878 }
879 }
880 #endif
881
882 //=============================================================================
883 //------------------------------PhaseIterGVN-----------------------------------
884 // Initialize hash table to fresh and clean for +VerifyOpto
885 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ),
886 _stack(C->live_nodes() >> 1),
887 _delay_transform(false) {
888 }
889
890 //------------------------------PhaseIterGVN-----------------------------------
891 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
892 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
893 _worklist( igvn->_worklist ),
894 _stack( igvn->_stack ),
895 _delay_transform(igvn->_delay_transform)
896 {
897 }
898
899 //------------------------------PhaseIterGVN-----------------------------------
900 // Initialize with previous PhaseGVN info from Parser
901 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
902 _worklist(*C->for_igvn()),
903 // TODO: Before incremental inlining it was allocated only once and it was fine. Now that
904 // the constructor is used in incremental inlining, this consumes too much memory:
905 // _stack(C->live_nodes() >> 1),
906 // So, as a band-aid, we replace this by:
907 _stack(C->comp_arena(), 32),
908 _delay_transform(false)
909 {
910 uint max;
911
912 // Dead nodes in the hash table inherited from GVN were not treated as
913 // roots during def-use info creation; hence they represent an invisible
914 // use. Clear them out.
915 max = _table.size();
916 for( uint i = 0; i < max; ++i ) {
917 Node *n = _table.at(i);
918 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
919 if( n->is_top() ) continue;
920 assert( false, "Parse::remove_useless_nodes missed this node");
921 hash_delete(n);
922 }
923 }
924
925 // Any Phis or Regions on the worklist probably had uses that could not
926 // make more progress because the uses were made while the Phis and Regions
927 // were in half-built states. Put all uses of Phis and Regions on worklist.
928 max = _worklist.size();
929 for( uint j = 0; j < max; j++ ) {
930 Node *n = _worklist.at(j);
931 uint uop = n->Opcode();
932 if( uop == Op_Phi || uop == Op_Region ||
933 n->is_Type() ||
934 n->is_Mem() )
935 add_users_to_worklist(n);
936 }
937 }
938
939 /**
940 * Initialize worklist for each node.
941 */
942 void PhaseIterGVN::init_worklist(Node* first) {
943 Unique_Node_List to_process;
944 to_process.push(first);
945
946 while (to_process.size() > 0) {
947 Node* n = to_process.pop();
948 if (!_worklist.member(n)) {
949 _worklist.push(n);
950
951 uint cnt = n->req();
952 for(uint i = 0; i < cnt; i++) {
953 Node* m = n->in(i);
954 if (m != NULL) {
955 to_process.push(m);
956 }
957 }
958 }
959 }
960 }
961
962 #ifndef PRODUCT
963 void PhaseIterGVN::verify_step(Node* n) {
964 if (VerifyIterativeGVN) {
965 _verify_window[_verify_counter % _verify_window_size] = n;
966 ++_verify_counter;
967 ResourceMark rm;
968 ResourceArea* area = Thread::current()->resource_area();
969 VectorSet old_space(area), new_space(area);
970 if (C->unique() < 1000 ||
971 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
972 ++_verify_full_passes;
973 Node::verify_recur(C->root(), -1, old_space, new_space);
974 }
975 const int verify_depth = 4;
976 for ( int i = 0; i < _verify_window_size; i++ ) {
977 Node* n = _verify_window[i];
978 if ( n == NULL ) continue;
979 if( n->in(0) == NodeSentinel ) { // xform_idom
980 _verify_window[i] = n->in(1);
981 --i; continue;
982 }
983 // Typical fanout is 1-2, so this call visits about 6 nodes.
984 Node::verify_recur(n, verify_depth, old_space, new_space);
985 }
986 }
987 }
988
989 void PhaseIterGVN::trace_PhaseIterGVN(Node* n, Node* nn, const Type* oldtype) {
990 if (TraceIterativeGVN) {
991 uint wlsize = _worklist.size();
992 const Type* newtype = type_or_null(n);
993 if (nn != n) {
994 // print old node
995 tty->print("< ");
996 if (oldtype != newtype && oldtype != NULL) {
997 oldtype->dump();
998 }
999 do { tty->print("\t"); } while (tty->position() < 16);
1000 tty->print("<");
1001 n->dump();
1002 }
1003 if (oldtype != newtype || nn != n) {
1004 // print new node and/or new type
1005 if (oldtype == NULL) {
1006 tty->print("* ");
1007 } else if (nn != n) {
1008 tty->print("> ");
1009 } else {
1010 tty->print("= ");
1011 }
1012 if (newtype == NULL) {
1013 tty->print("null");
1014 } else {
1015 newtype->dump();
1016 }
1017 do { tty->print("\t"); } while (tty->position() < 16);
1018 nn->dump();
1019 }
1020 if (Verbose && wlsize < _worklist.size()) {
1021 tty->print(" Push {");
1022 while (wlsize != _worklist.size()) {
1023 Node* pushed = _worklist.at(wlsize++);
1024 tty->print(" %d", pushed->_idx);
1025 }
1026 tty->print_cr(" }");
1027 }
1028 if (nn != n) {
1029 // ignore n, it might be subsumed
1030 verify_step((Node*) NULL);
1031 }
1032 }
1033 }
1034
1035 void PhaseIterGVN::init_verifyPhaseIterGVN() {
1036 _verify_counter = 0;
1037 _verify_full_passes = 0;
1038 for (int i = 0; i < _verify_window_size; i++) {
1039 _verify_window[i] = NULL;
1040 }
1041 #ifdef ASSERT
1042 // Verify that all modified nodes are on _worklist
1043 Unique_Node_List* modified_list = C->modified_nodes();
1044 while (modified_list != NULL && modified_list->size()) {
1045 Node* n = modified_list->pop();
1046 if (n->outcnt() != 0 && !n->is_Con() && !_worklist.member(n)) {
1047 n->dump();
1048 assert(false, "modified node is not on IGVN._worklist");
1049 }
1050 }
1051 #endif
1052 }
1053
1054 void PhaseIterGVN::verify_PhaseIterGVN() {
1055 #ifdef ASSERT
1056 // Verify nodes with changed inputs.
1057 Unique_Node_List* modified_list = C->modified_nodes();
1058 while (modified_list != NULL && modified_list->size()) {
1059 Node* n = modified_list->pop();
1060 if (n->outcnt() != 0 && !n->is_Con()) { // skip dead and Con nodes
1061 n->dump();
1062 assert(false, "modified node was not processed by IGVN.transform_old()");
1063 }
1064 }
1065 #endif
1066
1067 C->verify_graph_edges();
1068 if( VerifyOpto && allow_progress() ) {
1069 // Must turn off allow_progress to enable assert and break recursion
1070 C->root()->verify();
1071 { // Check if any progress was missed using IterGVN
1072 // Def-Use info enables transformations not attempted in wash-pass
1073 // e.g. Region/Phi cleanup, ...
1074 // Null-check elision -- may not have reached fixpoint
1075 // do not propagate to dominated nodes
1076 ResourceMark rm;
1077 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
1078 // Fill worklist completely
1079 igvn2.init_worklist(C->root());
1080
1081 igvn2.set_allow_progress(false);
1082 igvn2.optimize();
1083 igvn2.set_allow_progress(true);
1084 }
1085 }
1086 if (VerifyIterativeGVN && PrintOpto) {
1087 if (_verify_counter == _verify_full_passes) {
1088 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
1089 (int) _verify_full_passes);
1090 } else {
1091 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
1092 (int) _verify_counter, (int) _verify_full_passes);
1093 }
1094 }
1095
1096 #ifdef ASSERT
1097 while (modified_list->size()) {
1098 Node* n = modified_list->pop();
1099 n->dump();
1100 assert(false, "VerifyIterativeGVN: new modified node was added");
1101 }
1102 #endif
1103 }
1104 #endif /* PRODUCT */
1105
1106 #ifdef ASSERT
1107 /**
1108 * Dumps information that can help to debug the problem. A debug
1109 * build fails with an assert.
1110 */
1111 void PhaseIterGVN::dump_infinite_loop_info(Node* n) {
1112 n->dump(4);
1113 _worklist.dump();
1114 assert(false, "infinite loop in PhaseIterGVN::optimize");
1115 }
1116
1117 /**
1118 * Prints out information about IGVN if the 'verbose' option is used.
1119 */
1120 void PhaseIterGVN::trace_PhaseIterGVN_verbose(Node* n, int num_processed) {
1121 if (TraceIterativeGVN && Verbose) {
1122 tty->print(" Pop ");
1123 n->dump();
1124 if ((num_processed % 100) == 0) {
1125 _worklist.print_set();
1126 }
1127 }
1128 }
1129 #endif /* ASSERT */
1130
1131 void PhaseIterGVN::optimize() {
1132 DEBUG_ONLY(uint num_processed = 0;)
1133 NOT_PRODUCT(init_verifyPhaseIterGVN();)
1134
1135 uint loop_count = 0;
1136 // Pull from worklist and transform the node. If the node has changed,
1137 // update edge info and put uses on worklist.
1138 while(_worklist.size()) {
1139 if (C->check_node_count(NodeLimitFudgeFactor * 2, "Out of nodes")) {
1140 return;
1141 }
1142 Node* n = _worklist.pop();
1143 if (++loop_count >= K * C->live_nodes()) {
1144 DEBUG_ONLY(dump_infinite_loop_info(n);)
1145 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
1146 return;
1147 }
1148 DEBUG_ONLY(trace_PhaseIterGVN_verbose(n, num_processed++);)
1149 if (n->outcnt() != 0) {
1150 NOT_PRODUCT(const Type* oldtype = type_or_null(n));
1151 // Do the transformation
1152 Node* nn = transform_old(n);
1153 NOT_PRODUCT(trace_PhaseIterGVN(n, nn, oldtype);)
1154 } else if (!n->is_top()) {
1155 remove_dead_node(n);
1156 }
1157 }
1158 NOT_PRODUCT(verify_PhaseIterGVN();)
1159 }
1160
1161
1162 /**
1163 * Register a new node with the optimizer. Update the types array, the def-use
1164 * info. Put on worklist.
1165 */
1166 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1167 set_type_bottom(n);
1168 _worklist.push(n);
1169 if (orig != NULL) C->copy_node_notes_to(n, orig);
1170 return n;
1171 }
1172
1173 //------------------------------transform--------------------------------------
1174 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1175 Node *PhaseIterGVN::transform( Node *n ) {
1176 if (_delay_transform) {
1177 // Register the node but don't optimize for now
1178 register_new_node_with_optimizer(n);
1179 return n;
1180 }
1181
1182 // If brand new node, make space in type array, and give it a type.
1183 ensure_type_or_null(n);
1184 if (type_or_null(n) == NULL) {
1185 set_type_bottom(n);
1186 }
1187
1188 return transform_old(n);
1189 }
1190
1191 Node *PhaseIterGVN::transform_old(Node* n) {
1192 DEBUG_ONLY(uint loop_count = 0;);
1193 NOT_PRODUCT(set_transforms());
1194
1195 // Remove 'n' from hash table in case it gets modified
1196 _table.hash_delete(n);
1197 if (VerifyIterativeGVN) {
1198 assert(!_table.find_index(n->_idx), "found duplicate entry in table");
1199 }
1200
1201 // Apply the Ideal call in a loop until it no longer applies
1202 Node* k = n;
1203 DEBUG_ONLY(dead_loop_check(k);)
1204 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1205 C->remove_modified_node(k);
1206 Node* i = k->Ideal(this, /*can_reshape=*/true);
1207 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1208 #ifndef PRODUCT
1209 verify_step(k);
1210 if (i && VerifyOpto ) {
1211 if (!allow_progress()) {
1212 if (i->is_Add() && (i->outcnt() == 1)) {
1213 // Switched input to left side because this is the only use
1214 } else if (i->is_If() && (i->in(0) == NULL)) {
1215 // This IF is dead because it is dominated by an equivalent IF When
1216 // dominating if changed, info is not propagated sparsely to 'this'
1217 // Propagating this info further will spuriously identify other
1218 // progress.
1219 return i;
1220 } else
1221 set_progress();
1222 } else {
1223 set_progress();
1224 }
1225 }
1226 #endif
1227
1228 while (i != NULL) {
1229 #ifdef ASSERT
1230 if (loop_count >= K) {
1231 dump_infinite_loop_info(i);
1232 }
1233 loop_count++;
1234 #endif
1235 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1236 // Made a change; put users of original Node on worklist
1237 add_users_to_worklist(k);
1238 // Replacing root of transform tree?
1239 if (k != i) {
1240 // Make users of old Node now use new.
1241 subsume_node(k, i);
1242 k = i;
1243 }
1244 DEBUG_ONLY(dead_loop_check(k);)
1245 // Try idealizing again
1246 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1247 C->remove_modified_node(k);
1248 i = k->Ideal(this, /*can_reshape=*/true);
1249 assert(i != k || is_new || (i->outcnt() > 0), "don't return dead nodes");
1250 #ifndef PRODUCT
1251 verify_step(k);
1252 if (i && VerifyOpto) {
1253 set_progress();
1254 }
1255 #endif
1256 }
1257
1258 // If brand new node, make space in type array.
1259 ensure_type_or_null(k);
1260
1261 // See what kind of values 'k' takes on at runtime
1262 const Type* t = k->Value(this);
1263 assert(t != NULL, "value sanity");
1264
1265 // Since I just called 'Value' to compute the set of run-time values
1266 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1267 // cache Value. Later requests for the local phase->type of this Node can
1268 // use the cached Value instead of suffering with 'bottom_type'.
1269 if (type_or_null(k) != t) {
1270 #ifndef PRODUCT
1271 inc_new_values();
1272 set_progress();
1273 #endif
1274 set_type(k, t);
1275 // If k is a TypeNode, capture any more-precise type permanently into Node
1276 k->raise_bottom_type(t);
1277 // Move users of node to worklist
1278 add_users_to_worklist(k);
1279 }
1280 // If 'k' computes a constant, replace it with a constant
1281 if (t->singleton() && !k->is_Con()) {
1282 NOT_PRODUCT(set_progress();)
1283 Node* con = makecon(t); // Make a constant
1284 add_users_to_worklist(k);
1285 subsume_node(k, con); // Everybody using k now uses con
1286 return con;
1287 }
1288
1289 // Now check for Identities
1290 i = k->Identity(this); // Look for a nearby replacement
1291 if (i != k) { // Found? Return replacement!
1292 NOT_PRODUCT(set_progress();)
1293 add_users_to_worklist(k);
1294 subsume_node(k, i); // Everybody using k now uses i
1295 return i;
1296 }
1297
1298 // Global Value Numbering
1299 i = hash_find_insert(k); // Check for pre-existing node
1300 if (i && (i != k)) {
1301 // Return the pre-existing node if it isn't dead
1302 NOT_PRODUCT(set_progress();)
1303 add_users_to_worklist(k);
1304 subsume_node(k, i); // Everybody using k now uses i
1305 return i;
1306 }
1307
1308 // Return Idealized original
1309 return k;
1310 }
1311
1312 //---------------------------------saturate------------------------------------
1313 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1314 const Type* limit_type) const {
1315 return new_type->narrow(old_type);
1316 }
1317
1318 //------------------------------remove_globally_dead_node----------------------
1319 // Kill a globally dead Node. All uses are also globally dead and are
1320 // aggressively trimmed.
1321 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1322 enum DeleteProgress {
1323 PROCESS_INPUTS,
1324 PROCESS_OUTPUTS
1325 };
1326 assert(_stack.is_empty(), "not empty");
1327 _stack.push(dead, PROCESS_INPUTS);
1328
1329 while (_stack.is_nonempty()) {
1330 dead = _stack.node();
1331 uint progress_state = _stack.index();
1332 assert(dead != C->root(), "killing root, eh?");
1333 assert(!dead->is_top(), "add check for top when pushing");
1334 NOT_PRODUCT( set_progress(); )
1335 if (progress_state == PROCESS_INPUTS) {
1336 // After following inputs, continue to outputs
1337 _stack.set_index(PROCESS_OUTPUTS);
1338 if (!dead->is_Con()) { // Don't kill cons but uses
1339 bool recurse = false;
1340 // Remove from hash table
1341 _table.hash_delete( dead );
1342 // Smash all inputs to 'dead', isolating him completely
1343 for (uint i = 0; i < dead->req(); i++) {
1344 Node *in = dead->in(i);
1345 if (in != NULL && in != C->top()) { // Points to something?
1346 int nrep = dead->replace_edge(in, NULL); // Kill edges
1347 assert((nrep > 0), "sanity");
1348 if (in->outcnt() == 0) { // Made input go dead?
1349 _stack.push(in, PROCESS_INPUTS); // Recursively remove
1350 recurse = true;
1351 } else if (in->outcnt() == 1 &&
1352 in->has_special_unique_user()) {
1353 _worklist.push(in->unique_out());
1354 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1355 if (in->Opcode() == Op_Region) {
1356 _worklist.push(in);
1357 } else if (in->is_Store()) {
1358 DUIterator_Fast imax, i = in->fast_outs(imax);
1359 _worklist.push(in->fast_out(i));
1360 i++;
1361 if (in->outcnt() == 2) {
1362 _worklist.push(in->fast_out(i));
1363 i++;
1364 }
1365 assert(!(i < imax), "sanity");
1366 }
1367 }
1368 if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory &&
1369 in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) {
1370 // A Load that directly follows an InitializeNode is
1371 // going away. The Stores that follow are candidates
1372 // again to be captured by the InitializeNode.
1373 for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) {
1374 Node *n = in->fast_out(j);
1375 if (n->is_Store()) {
1376 _worklist.push(n);
1377 }
1378 }
1379 }
1380 } // if (in != NULL && in != C->top())
1381 } // for (uint i = 0; i < dead->req(); i++)
1382 if (recurse) {
1383 continue;
1384 }
1385 } // if (!dead->is_Con())
1386 } // if (progress_state == PROCESS_INPUTS)
1387
1388 // Aggressively kill globally dead uses
1389 // (Rather than pushing all the outs at once, we push one at a time,
1390 // plus the parent to resume later, because of the indefinite number
1391 // of edge deletions per loop trip.)
1392 if (dead->outcnt() > 0) {
1393 // Recursively remove output edges
1394 _stack.push(dead->raw_out(0), PROCESS_INPUTS);
1395 } else {
1396 // Finished disconnecting all input and output edges.
1397 _stack.pop();
1398 // Remove dead node from iterative worklist
1399 _worklist.remove(dead);
1400 C->remove_modified_node(dead);
1401 // Constant node that has no out-edges and has only one in-edge from
1402 // root is usually dead. However, sometimes reshaping walk makes
1403 // it reachable by adding use edges. So, we will NOT count Con nodes
1404 // as dead to be conservative about the dead node count at any
1405 // given time.
1406 if (!dead->is_Con()) {
1407 C->record_dead_node(dead->_idx);
1408 }
1409 if (dead->is_macro()) {
1410 C->remove_macro_node(dead);
1411 }
1412 if (dead->is_expensive()) {
1413 C->remove_expensive_node(dead);
1414 }
1415 }
1416 } // while (_stack.is_nonempty())
1417 }
1418
1419 //------------------------------subsume_node-----------------------------------
1420 // Remove users from node 'old' and add them to node 'nn'.
1421 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1422 assert( old != hash_find(old), "should already been removed" );
1423 assert( old != C->top(), "cannot subsume top node");
1424 // Copy debug or profile information to the new version:
1425 C->copy_node_notes_to(nn, old);
1426 // Move users of node 'old' to node 'nn'
1427 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1428 Node* use = old->last_out(i); // for each use...
1429 // use might need re-hashing (but it won't if it's a new node)
1430 rehash_node_delayed(use);
1431 // Update use-def info as well
1432 // We remove all occurrences of old within use->in,
1433 // so as to avoid rehashing any node more than once.
1434 // The hash table probe swamps any outer loop overhead.
1435 uint num_edges = 0;
1436 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1437 if (use->in(j) == old) {
1438 use->set_req(j, nn);
1439 ++num_edges;
1440 }
1441 }
1442 i -= num_edges; // we deleted 1 or more copies of this edge
1443 }
1444
1445 // Smash all inputs to 'old', isolating him completely
1446 Node *temp = new Node(1);
1447 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1448 remove_dead_node( old );
1449 temp->del_req(0); // Yank bogus edge
1450 #ifndef PRODUCT
1451 if( VerifyIterativeGVN ) {
1452 for ( int i = 0; i < _verify_window_size; i++ ) {
1453 if ( _verify_window[i] == old )
1454 _verify_window[i] = nn;
1455 }
1456 }
1457 #endif
1458 _worklist.remove(temp); // this can be necessary
1459 temp->destruct(); // reuse the _idx of this little guy
1460 }
1461
1462 //------------------------------add_users_to_worklist--------------------------
1463 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1464 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1465 _worklist.push(n->fast_out(i)); // Push on worklist
1466 }
1467 }
1468
1469 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1470 add_users_to_worklist0(n);
1471
1472 // Move users of node to worklist
1473 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1474 Node* use = n->fast_out(i); // Get use
1475
1476 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1477 use->is_Store() ) // Enable store/load same address
1478 add_users_to_worklist0(use);
1479
1480 // If we changed the receiver type to a call, we need to revisit
1481 // the Catch following the call. It's looking for a non-NULL
1482 // receiver to know when to enable the regular fall-through path
1483 // in addition to the NullPtrException path.
1484 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1485 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
1486 if (p != NULL) {
1487 add_users_to_worklist0(p);
1488 }
1489 }
1490
1491 uint use_op = use->Opcode();
1492 if(use->is_Cmp()) { // Enable CMP/BOOL optimization
1493 add_users_to_worklist(use); // Put Bool on worklist
1494 if (use->outcnt() > 0) {
1495 Node* bol = use->raw_out(0);
1496 if (bol->outcnt() > 0) {
1497 Node* iff = bol->raw_out(0);
1498 if (use_op == Op_CmpI &&
1499 iff->is_CountedLoopEnd()) {
1500 CountedLoopEndNode* cle = iff->as_CountedLoopEnd();
1501 if (cle->limit() == n && cle->phi() != NULL) {
1502 // If an opaque node feeds into the limit condition of a
1503 // CountedLoop, we need to process the Phi node for the
1504 // induction variable when the opaque node is removed:
1505 // the range of values taken by the Phi is now known and
1506 // so its type is also known.
1507 _worklist.push(cle->phi());
1508 }
1509 } else if (iff->outcnt() == 2) {
1510 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1511 // phi merging either 0 or 1 onto the worklist
1512 Node* ifproj0 = iff->raw_out(0);
1513 Node* ifproj1 = iff->raw_out(1);
1514 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1515 Node* region0 = ifproj0->raw_out(0);
1516 Node* region1 = ifproj1->raw_out(0);
1517 if( region0 == region1 )
1518 add_users_to_worklist0(region0);
1519 }
1520 }
1521 }
1522 }
1523 if (use_op == Op_CmpI) {
1524 Node* in1 = use->in(1);
1525 for (uint i = 0; i < in1->outcnt(); i++) {
1526 if (in1->raw_out(i)->Opcode() == Op_CastII) {
1527 Node* castii = in1->raw_out(i);
1528 if (castii->in(0) != NULL && castii->in(0)->in(0) != NULL && castii->in(0)->in(0)->is_If()) {
1529 Node* ifnode = castii->in(0)->in(0);
1530 if (ifnode->in(1) != NULL && ifnode->in(1)->is_Bool() && ifnode->in(1)->in(1) == use) {
1531 // Reprocess a CastII node that may depend on an
1532 // opaque node value when the opaque node is
1533 // removed. In case it carries a dependency we can do
1534 // a better job of computing its type.
1535 _worklist.push(castii);
1536 }
1537 }
1538 }
1539 }
1540 }
1541 }
1542
1543 // If changed Cast input, check Phi users for simple cycles
1544 if (use->is_ConstraintCast()) {
1545 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1546 Node* u = use->fast_out(i2);
1547 if (u->is_Phi())
1548 _worklist.push(u);
1549 }
1550 }
1551 // If changed LShift inputs, check RShift users for useless sign-ext
1552 if( use_op == Op_LShiftI ) {
1553 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1554 Node* u = use->fast_out(i2);
1555 if (u->Opcode() == Op_RShiftI)
1556 _worklist.push(u);
1557 }
1558 }
1559 // If changed AddI/SubI inputs, check CmpU for range check optimization.
1560 if (use_op == Op_AddI || use_op == Op_SubI) {
1561 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1562 Node* u = use->fast_out(i2);
1563 if (u->is_Cmp() && (u->Opcode() == Op_CmpU)) {
1564 _worklist.push(u);
1565 }
1566 }
1567 }
1568 // If changed AddP inputs, check Stores for loop invariant
1569 if( use_op == Op_AddP ) {
1570 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1571 Node* u = use->fast_out(i2);
1572 if (u->is_Mem())
1573 _worklist.push(u);
1574 }
1575 }
1576 // If changed initialization activity, check dependent Stores
1577 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1578 InitializeNode* init = use->as_Allocate()->initialization();
1579 if (init != NULL) {
1580 Node* imem = init->proj_out(TypeFunc::Memory);
1581 if (imem != NULL) add_users_to_worklist0(imem);
1582 }
1583 }
1584 if (use_op == Op_Initialize) {
1585 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
1586 if (imem != NULL) add_users_to_worklist0(imem);
1587 }
1588 }
1589 }
1590
1591 /**
1592 * Remove the speculative part of all types that we know of
1593 */
1594 void PhaseIterGVN::remove_speculative_types() {
1595 assert(UseTypeSpeculation, "speculation is off");
1596 for (uint i = 0; i < _types.Size(); i++) {
1597 const Type* t = _types.fast_lookup(i);
1598 if (t != NULL) {
1599 _types.map(i, t->remove_speculative());
1600 }
1601 }
1602 _table.check_no_speculative_types();
1603 }
1604
1605 //=============================================================================
1606 #ifndef PRODUCT
1607 uint PhaseCCP::_total_invokes = 0;
1608 uint PhaseCCP::_total_constants = 0;
1609 #endif
1610 //------------------------------PhaseCCP---------------------------------------
1611 // Conditional Constant Propagation, ala Wegman & Zadeck
1612 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1613 NOT_PRODUCT( clear_constants(); )
1614 assert( _worklist.size() == 0, "" );
1615 // Clear out _nodes from IterGVN. Must be clear to transform call.
1616 _nodes.clear(); // Clear out from IterGVN
1617 analyze();
1618 }
1619
1620 #ifndef PRODUCT
1621 //------------------------------~PhaseCCP--------------------------------------
1622 PhaseCCP::~PhaseCCP() {
1623 inc_invokes();
1624 _total_constants += count_constants();
1625 }
1626 #endif
1627
1628
1629 #ifdef ASSERT
1630 static bool ccp_type_widens(const Type* t, const Type* t0) {
1631 assert(t->meet(t0) == t, "Not monotonic");
1632 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1633 case Type::Int:
1634 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1635 break;
1636 case Type::Long:
1637 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1638 break;
1639 }
1640 return true;
1641 }
1642 #endif //ASSERT
1643
1644 //------------------------------analyze----------------------------------------
1645 void PhaseCCP::analyze() {
1646 // Initialize all types to TOP, optimistic analysis
1647 for (int i = C->unique() - 1; i >= 0; i--) {
1648 _types.map(i,Type::TOP);
1649 }
1650
1651 // Push root onto worklist
1652 Unique_Node_List worklist;
1653 worklist.push(C->root());
1654
1655 // Pull from worklist; compute new value; push changes out.
1656 // This loop is the meat of CCP.
1657 while( worklist.size() ) {
1658 Node *n = worklist.pop();
1659 const Type *t = n->Value(this);
1660 if (t != type(n)) {
1661 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1662 #ifndef PRODUCT
1663 if( TracePhaseCCP ) {
1664 t->dump();
1665 do { tty->print("\t"); } while (tty->position() < 16);
1666 n->dump();
1667 }
1668 #endif
1669 set_type(n, t);
1670 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1671 Node* m = n->fast_out(i); // Get user
1672 if (m->is_Region()) { // New path to Region? Must recheck Phis too
1673 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1674 Node* p = m->fast_out(i2); // Propagate changes to uses
1675 if (p->bottom_type() != type(p)) { // If not already bottomed out
1676 worklist.push(p); // Propagate change to user
1677 }
1678 }
1679 }
1680 // If we changed the receiver type to a call, we need to revisit
1681 // the Catch following the call. It's looking for a non-NULL
1682 // receiver to know when to enable the regular fall-through path
1683 // in addition to the NullPtrException path
1684 if (m->is_Call()) {
1685 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1686 Node* p = m->fast_out(i2); // Propagate changes to uses
1687 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1) {
1688 worklist.push(p->unique_out());
1689 }
1690 }
1691 }
1692 if (m->bottom_type() != type(m)) { // If not already bottomed out
1693 worklist.push(m); // Propagate change to user
1694 }
1695
1696 // CmpU nodes can get their type information from two nodes up in the
1697 // graph (instead of from the nodes immediately above). Make sure they
1698 // are added to the worklist if nodes they depend on are updated, since
1699 // they could be missed and get wrong types otherwise.
1700 uint m_op = m->Opcode();
1701 if (m_op == Op_AddI || m_op == Op_SubI) {
1702 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1703 Node* p = m->fast_out(i2); // Propagate changes to uses
1704 if (p->Opcode() == Op_CmpU) {
1705 // Got a CmpU which might need the new type information from node n.
1706 if(p->bottom_type() != type(p)) { // If not already bottomed out
1707 worklist.push(p); // Propagate change to user
1708 }
1709 }
1710 }
1711 }
1712 }
1713 }
1714 }
1715 }
1716
1717 //------------------------------do_transform-----------------------------------
1718 // Top level driver for the recursive transformer
1719 void PhaseCCP::do_transform() {
1720 // Correct leaves of new-space Nodes; they point to old-space.
1721 C->set_root( transform(C->root())->as_Root() );
1722 assert( C->top(), "missing TOP node" );
1723 assert( C->root(), "missing root" );
1724 }
1725
1726 //------------------------------transform--------------------------------------
1727 // Given a Node in old-space, clone him into new-space.
1728 // Convert any of his old-space children into new-space children.
1729 Node *PhaseCCP::transform( Node *n ) {
1730 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1731 if( new_node != NULL )
1732 return new_node; // Been there, done that, return old answer
1733 new_node = transform_once(n); // Check for constant
1734 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1735
1736 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1737 GrowableArray <Node *> trstack(C->live_nodes() >> 1);
1738
1739 trstack.push(new_node); // Process children of cloned node
1740 while ( trstack.is_nonempty() ) {
1741 Node *clone = trstack.pop();
1742 uint cnt = clone->req();
1743 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1744 Node *input = clone->in(i);
1745 if( input != NULL ) { // Ignore NULLs
1746 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1747 if( new_input == NULL ) {
1748 new_input = transform_once(input); // Check for constant
1749 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1750 trstack.push(new_input);
1751 }
1752 assert( new_input == clone->in(i), "insanity check");
1753 }
1754 }
1755 }
1756 return new_node;
1757 }
1758
1759
1760 //------------------------------transform_once---------------------------------
1761 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1762 Node *PhaseCCP::transform_once( Node *n ) {
1763 const Type *t = type(n);
1764 // Constant? Use constant Node instead
1765 if( t->singleton() ) {
1766 Node *nn = n; // Default is to return the original constant
1767 if( t == Type::TOP ) {
1768 // cache my top node on the Compile instance
1769 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1770 C->set_cached_top_node(ConNode::make(Type::TOP));
1771 set_type(C->top(), Type::TOP);
1772 }
1773 nn = C->top();
1774 }
1775 if( !n->is_Con() ) {
1776 if( t != Type::TOP ) {
1777 nn = makecon(t); // ConNode::make(t);
1778 NOT_PRODUCT( inc_constants(); )
1779 } else if( n->is_Region() ) { // Unreachable region
1780 // Note: nn == C->top()
1781 n->set_req(0, NULL); // Cut selfreference
1782 // Eagerly remove dead phis to avoid phis copies creation.
1783 for (DUIterator i = n->outs(); n->has_out(i); i++) {
1784 Node* m = n->out(i);
1785 if( m->is_Phi() ) {
1786 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1787 replace_node(m, nn);
1788 --i; // deleted this phi; rescan starting with next position
1789 }
1790 }
1791 }
1792 replace_node(n,nn); // Update DefUse edges for new constant
1793 }
1794 return nn;
1795 }
1796
1797 // If x is a TypeNode, capture any more-precise type permanently into Node
1798 if (t != n->bottom_type()) {
1799 hash_delete(n); // changing bottom type may force a rehash
1800 n->raise_bottom_type(t);
1801 _worklist.push(n); // n re-enters the hash table via the worklist
1802 }
1803
1804 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1805 switch( n->Opcode() ) {
1806 case Op_FastLock: // Revisit FastLocks for lock coarsening
1807 case Op_If:
1808 case Op_CountedLoopEnd:
1809 case Op_Region:
1810 case Op_Loop:
1811 case Op_CountedLoop:
1812 case Op_Conv2B:
1813 case Op_Opaque1:
1814 case Op_Opaque2:
1815 _worklist.push(n);
1816 break;
1817 default:
1818 break;
1819 }
1820
1821 return n;
1822 }
1823
1824 //---------------------------------saturate------------------------------------
1825 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1826 const Type* limit_type) const {
1827 const Type* wide_type = new_type->widen(old_type, limit_type);
1828 if (wide_type != new_type) { // did we widen?
1829 // If so, we may have widened beyond the limit type. Clip it back down.
1830 new_type = wide_type->filter(limit_type);
1831 }
1832 return new_type;
1833 }
1834
1835 //------------------------------print_statistics-------------------------------
1836 #ifndef PRODUCT
1837 void PhaseCCP::print_statistics() {
1838 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1839 }
1840 #endif
1841
1842
1843 //=============================================================================
1844 #ifndef PRODUCT
1845 uint PhasePeephole::_total_peepholes = 0;
1846 #endif
1847 //------------------------------PhasePeephole----------------------------------
1848 // Conditional Constant Propagation, ala Wegman & Zadeck
1849 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1850 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1851 NOT_PRODUCT( clear_peepholes(); )
1852 }
1853
1854 #ifndef PRODUCT
1855 //------------------------------~PhasePeephole---------------------------------
1856 PhasePeephole::~PhasePeephole() {
1857 _total_peepholes += count_peepholes();
1858 }
1859 #endif
1860
1861 //------------------------------transform--------------------------------------
1862 Node *PhasePeephole::transform( Node *n ) {
1863 ShouldNotCallThis();
1864 return NULL;
1865 }
1866
1867 //------------------------------do_transform-----------------------------------
1868 void PhasePeephole::do_transform() {
1869 bool method_name_not_printed = true;
1870
1871 // Examine each basic block
1872 for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) {
1873 Block* block = _cfg.get_block(block_number);
1874 bool block_not_printed = true;
1875
1876 // and each instruction within a block
1877 uint end_index = block->number_of_nodes();
1878 // block->end_idx() not valid after PhaseRegAlloc
1879 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
1880 Node *n = block->get_node(instruction_index);
1881 if( n->is_Mach() ) {
1882 MachNode *m = n->as_Mach();
1883 int deleted_count = 0;
1884 // check for peephole opportunities
1885 MachNode *m2 = m->peephole(block, instruction_index, _regalloc, deleted_count);
1886 if( m2 != NULL ) {
1887 #ifndef PRODUCT
1888 if( PrintOptoPeephole ) {
1889 // Print method, first time only
1890 if( C->method() && method_name_not_printed ) {
1891 C->method()->print_short_name(); tty->cr();
1892 method_name_not_printed = false;
1893 }
1894 // Print this block
1895 if( Verbose && block_not_printed) {
1896 tty->print_cr("in block");
1897 block->dump();
1898 block_not_printed = false;
1899 }
1900 // Print instructions being deleted
1901 for( int i = (deleted_count - 1); i >= 0; --i ) {
1902 block->get_node(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
1903 }
1904 tty->print_cr("replaced with");
1905 // Print new instruction
1906 m2->format(_regalloc);
1907 tty->print("\n\n");
1908 }
1909 #endif
1910 // Remove old nodes from basic block and update instruction_index
1911 // (old nodes still exist and may have edges pointing to them
1912 // as register allocation info is stored in the allocator using
1913 // the node index to live range mappings.)
1914 uint safe_instruction_index = (instruction_index - deleted_count);
1915 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
1916 block->remove_node( instruction_index );
1917 }
1918 // install new node after safe_instruction_index
1919 block->insert_node(m2, safe_instruction_index + 1);
1920 end_index = block->number_of_nodes() - 1; // Recompute new block size
1921 NOT_PRODUCT( inc_peepholes(); )
1922 }
1923 }
1924 }
1925 }
1926 }
1927
1928 //------------------------------print_statistics-------------------------------
1929 #ifndef PRODUCT
1930 void PhasePeephole::print_statistics() {
1931 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
1932 }
1933 #endif
1934
1935
1936 //=============================================================================
1937 //------------------------------set_req_X--------------------------------------
1938 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
1939 assert( is_not_dead(n), "can not use dead node");
1940 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
1941 Node *old = in(i);
1942 set_req(i, n);
1943
1944 // old goes dead?
1945 if( old ) {
1946 switch (old->outcnt()) {
1947 case 0:
1948 // Put into the worklist to kill later. We do not kill it now because the
1949 // recursive kill will delete the current node (this) if dead-loop exists
1950 if (!old->is_top())
1951 igvn->_worklist.push( old );
1952 break;
1953 case 1:
1954 if( old->is_Store() || old->has_special_unique_user() )
1955 igvn->add_users_to_worklist( old );
1956 break;
1957 case 2:
1958 if( old->is_Store() )
1959 igvn->add_users_to_worklist( old );
1960 if( old->Opcode() == Op_Region )
1961 igvn->_worklist.push(old);
1962 break;
1963 case 3:
1964 if( old->Opcode() == Op_Region ) {
1965 igvn->_worklist.push(old);
1966 igvn->add_users_to_worklist( old );
1967 }
1968 break;
1969 default:
1970 break;
1971 }
1972 }
1973
1974 }
1975
1976 //-------------------------------replace_by-----------------------------------
1977 // Using def-use info, replace one node for another. Follow the def-use info
1978 // to all users of the OLD node. Then make all uses point to the NEW node.
1979 void Node::replace_by(Node *new_node) {
1980 assert(!is_top(), "top node has no DU info");
1981 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
1982 Node* use = last_out(i);
1983 uint uses_found = 0;
1984 for (uint j = 0; j < use->len(); j++) {
1985 if (use->in(j) == this) {
1986 if (j < use->req())
1987 use->set_req(j, new_node);
1988 else use->set_prec(j, new_node);
1989 uses_found++;
1990 }
1991 }
1992 i -= uses_found; // we deleted 1 or more copies of this edge
1993 }
1994 }
1995
1996 //=============================================================================
1997 //-----------------------------------------------------------------------------
1998 void Type_Array::grow( uint i ) {
1999 if( !_max ) {
2000 _max = 1;
2001 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
2002 _types[0] = NULL;
2003 }
2004 uint old = _max;
2005 while( i >= _max ) _max <<= 1; // Double to fit
2006 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
2007 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
2008 }
2009
2010 //------------------------------dump-------------------------------------------
2011 #ifndef PRODUCT
2012 void Type_Array::dump() const {
2013 uint max = Size();
2014 for( uint i = 0; i < max; i++ ) {
2015 if( _types[i] != NULL ) {
2016 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
2017 }
2018 }
2019 }
2020 #endif