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