Mercurial > jdk8-mips64-public > hotspot / file revision
src/share/vm/opto/phaseX.cpp@96ef09c26978
src/share/vm/opto/phaseX.cpp
Sat, 16 Mar 2013 07:39:14 -0700
- author
- morris
- date
- Sat, 16 Mar 2013 07:39:14 -0700
- changeset 4760
- 96ef09c26978
- parent 4657
- 6931f425c517
- child 4868
- 30f42e691e70
- permissions
- -rw-r--r--
8009166: [parfait] Null pointer deference in hotspot/src/share/vm/opto/type.cpp
Summary: add guarantee() to as_instance_type()
Reviewed-by: kvn, twisti
1 /*
2 * Copyright (c) 1997, 2012, 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 */
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"
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 }
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 }
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 }
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 }
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 }
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 }
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 }
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 }
184 }
185 ShouldNotReachHere();
186 return NULL;
187 }
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;
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 }
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 }
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 }
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 }
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
305 memset( _table, 0, _max * sizeof(Node*) );
306 }
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) {
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 }
326 #ifndef PRODUCT
327 //------------------------------dump-------------------------------------------
328 // Dump statistics for the hash table
329 void NodeHash::dump() {
330 _total_inserts += _inserts;
331 _total_insert_probes += _insert_probes;
332 if (PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0)) {
333 if (WizardMode) {
334 for (uint i=0; i<_max; i++) {
335 if (_table[i])
336 tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
337 }
338 }
339 tty->print("\nGVN Hash stats: %d grows to %d max_size\n", _grows, _max);
340 tty->print(" %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
341 tty->print(" %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
342 tty->print(" %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
343 // sentinels increase lookup cost, but not insert cost
344 assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
345 assert( _inserts+(_inserts>>3) < _max, "table too full" );
346 assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
347 }
348 }
350 Node *NodeHash::find_index(uint idx) { // For debugging
351 // Find an entry by its index value
352 for( uint i = 0; i < _max; i++ ) {
353 Node *m = _table[i];
354 if( !m || m == _sentinel ) continue;
355 if( m->_idx == (uint)idx ) return m;
356 }
357 return NULL;
358 }
359 #endif
361 #ifdef ASSERT
362 NodeHash::~NodeHash() {
363 // Unlock all nodes upon destruction of table.
364 if (_table != (Node**)badAddress) clear();
365 }
367 void NodeHash::operator=(const NodeHash& nh) {
368 // Unlock all nodes upon replacement of table.
369 if (&nh == this) return;
370 if (_table != (Node**)badAddress) clear();
371 memcpy(this, &nh, sizeof(*this));
372 // Do not increment hash_lock counts again.
373 // Instead, be sure we never again use the source table.
374 ((NodeHash*)&nh)->_table = (Node**)badAddress;
375 }
378 #endif
381 //=============================================================================
382 //------------------------------PhaseRemoveUseless-----------------------------
383 // 1) Use a breadthfirst walk to collect useful nodes reachable from root.
384 PhaseRemoveUseless::PhaseRemoveUseless( PhaseGVN *gvn, Unique_Node_List *worklist ) : Phase(Remove_Useless),
385 _useful(Thread::current()->resource_area()) {
387 // Implementation requires 'UseLoopSafepoints == true' and an edge from root
388 // to each SafePointNode at a backward branch. Inserted in add_safepoint().
389 if( !UseLoopSafepoints || !OptoRemoveUseless ) return;
391 // Identify nodes that are reachable from below, useful.
392 C->identify_useful_nodes(_useful);
393 // Update dead node list
394 C->update_dead_node_list(_useful);
396 // Remove all useless nodes from PhaseValues' recorded types
397 // Must be done before disconnecting nodes to preserve hash-table-invariant
398 gvn->remove_useless_nodes(_useful.member_set());
400 // Remove all useless nodes from future worklist
401 worklist->remove_useless_nodes(_useful.member_set());
403 // Disconnect 'useless' nodes that are adjacent to useful nodes
404 C->remove_useless_nodes(_useful);
406 // Remove edges from "root" to each SafePoint at a backward branch.
407 // They were inserted during parsing (see add_safepoint()) to make infinite
408 // loops without calls or exceptions visible to root, i.e., useful.
409 Node *root = C->root();
410 if( root != NULL ) {
411 for( uint i = root->req(); i < root->len(); ++i ) {
412 Node *n = root->in(i);
413 if( n != NULL && n->is_SafePoint() ) {
414 root->rm_prec(i);
415 --i;
416 }
417 }
418 }
419 }
422 //=============================================================================
423 //------------------------------PhaseTransform---------------------------------
424 PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
425 _arena(Thread::current()->resource_area()),
426 _nodes(_arena),
427 _types(_arena)
428 {
429 init_con_caches();
430 #ifndef PRODUCT
431 clear_progress();
432 clear_transforms();
433 set_allow_progress(true);
434 #endif
435 // Force allocation for currently existing nodes
436 _types.map(C->unique(), NULL);
437 }
439 //------------------------------PhaseTransform---------------------------------
440 PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
441 _arena(arena),
442 _nodes(arena),
443 _types(arena)
444 {
445 init_con_caches();
446 #ifndef PRODUCT
447 clear_progress();
448 clear_transforms();
449 set_allow_progress(true);
450 #endif
451 // Force allocation for currently existing nodes
452 _types.map(C->unique(), NULL);
453 }
455 //------------------------------PhaseTransform---------------------------------
456 // Initialize with previously generated type information
457 PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
458 _arena(pt->_arena),
459 _nodes(pt->_nodes),
460 _types(pt->_types)
461 {
462 init_con_caches();
463 #ifndef PRODUCT
464 clear_progress();
465 clear_transforms();
466 set_allow_progress(true);
467 #endif
468 }
470 void PhaseTransform::init_con_caches() {
471 memset(_icons,0,sizeof(_icons));
472 memset(_lcons,0,sizeof(_lcons));
473 memset(_zcons,0,sizeof(_zcons));
474 }
477 //--------------------------------find_int_type--------------------------------
478 const TypeInt* PhaseTransform::find_int_type(Node* n) {
479 if (n == NULL) return NULL;
480 // Call type_or_null(n) to determine node's type since we might be in
481 // parse phase and call n->Value() may return wrong type.
482 // (For example, a phi node at the beginning of loop parsing is not ready.)
483 const Type* t = type_or_null(n);
484 if (t == NULL) return NULL;
485 return t->isa_int();
486 }
489 //-------------------------------find_long_type--------------------------------
490 const TypeLong* PhaseTransform::find_long_type(Node* n) {
491 if (n == NULL) return NULL;
492 // (See comment above on type_or_null.)
493 const Type* t = type_or_null(n);
494 if (t == NULL) return NULL;
495 return t->isa_long();
496 }
499 #ifndef PRODUCT
500 void PhaseTransform::dump_old2new_map() const {
501 _nodes.dump();
502 }
504 void PhaseTransform::dump_new( uint nidx ) const {
505 for( uint i=0; i<_nodes.Size(); i++ )
506 if( _nodes[i] && _nodes[i]->_idx == nidx ) {
507 _nodes[i]->dump();
508 tty->cr();
509 tty->print_cr("Old index= %d",i);
510 return;
511 }
512 tty->print_cr("Node %d not found in the new indices", nidx);
513 }
515 //------------------------------dump_types-------------------------------------
516 void PhaseTransform::dump_types( ) const {
517 _types.dump();
518 }
520 //------------------------------dump_nodes_and_types---------------------------
521 void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
522 VectorSet visited(Thread::current()->resource_area());
523 dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
524 }
526 //------------------------------dump_nodes_and_types_recur---------------------
527 void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
528 if( !n ) return;
529 if( depth == 0 ) return;
530 if( visited.test_set(n->_idx) ) return;
531 for( uint i=0; i<n->len(); i++ ) {
532 if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
533 dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
534 }
535 n->dump();
536 if (type_or_null(n) != NULL) {
537 tty->print(" "); type(n)->dump(); tty->cr();
538 }
539 }
541 #endif
544 //=============================================================================
545 //------------------------------PhaseValues------------------------------------
546 // Set minimum table size to "255"
547 PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
548 NOT_PRODUCT( clear_new_values(); )
549 }
551 //------------------------------PhaseValues------------------------------------
552 // Set minimum table size to "255"
553 PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
554 _table(&ptv->_table) {
555 NOT_PRODUCT( clear_new_values(); )
556 }
558 //------------------------------PhaseValues------------------------------------
559 // Used by +VerifyOpto. Clear out hash table but copy _types array.
560 PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
561 _table(ptv->arena(),ptv->_table.size()) {
562 NOT_PRODUCT( clear_new_values(); )
563 }
565 //------------------------------~PhaseValues-----------------------------------
566 #ifndef PRODUCT
567 PhaseValues::~PhaseValues() {
568 _table.dump();
570 // Statistics for value progress and efficiency
571 if( PrintCompilation && Verbose && WizardMode ) {
572 tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
573 is_IterGVN() ? "Iter" : " ", C->unique(), made_progress(), made_transforms(), made_new_values());
574 if( made_transforms() != 0 ) {
575 tty->print_cr(" ratio %f", made_progress()/(float)made_transforms() );
576 } else {
577 tty->cr();
578 }
579 }
580 }
581 #endif
583 //------------------------------makecon----------------------------------------
584 ConNode* PhaseTransform::makecon(const Type *t) {
585 assert(t->singleton(), "must be a constant");
586 assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
587 switch (t->base()) { // fast paths
588 case Type::Half:
589 case Type::Top: return (ConNode*) C->top();
590 case Type::Int: return intcon( t->is_int()->get_con() );
591 case Type::Long: return longcon( t->is_long()->get_con() );
592 }
593 if (t->is_zero_type())
594 return zerocon(t->basic_type());
595 return uncached_makecon(t);
596 }
598 //--------------------------uncached_makecon-----------------------------------
599 // Make an idealized constant - one of ConINode, ConPNode, etc.
600 ConNode* PhaseValues::uncached_makecon(const Type *t) {
601 assert(t->singleton(), "must be a constant");
602 ConNode* x = ConNode::make(C, t);
603 ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
604 if (k == NULL) {
605 set_type(x, t); // Missed, provide type mapping
606 GrowableArray<Node_Notes*>* nna = C->node_note_array();
607 if (nna != NULL) {
608 Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
609 loc->clear(); // do not put debug info on constants
610 }
611 } else {
612 x->destruct(); // Hit, destroy duplicate constant
613 x = k; // use existing constant
614 }
615 return x;
616 }
618 //------------------------------intcon-----------------------------------------
619 // Fast integer constant. Same as "transform(new ConINode(TypeInt::make(i)))"
620 ConINode* PhaseTransform::intcon(int i) {
621 // Small integer? Check cache! Check that cached node is not dead
622 if (i >= _icon_min && i <= _icon_max) {
623 ConINode* icon = _icons[i-_icon_min];
624 if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
625 return icon;
626 }
627 ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
628 assert(icon->is_Con(), "");
629 if (i >= _icon_min && i <= _icon_max)
630 _icons[i-_icon_min] = icon; // Cache small integers
631 return icon;
632 }
634 //------------------------------longcon----------------------------------------
635 // Fast long constant.
636 ConLNode* PhaseTransform::longcon(jlong l) {
637 // Small integer? Check cache! Check that cached node is not dead
638 if (l >= _lcon_min && l <= _lcon_max) {
639 ConLNode* lcon = _lcons[l-_lcon_min];
640 if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
641 return lcon;
642 }
643 ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
644 assert(lcon->is_Con(), "");
645 if (l >= _lcon_min && l <= _lcon_max)
646 _lcons[l-_lcon_min] = lcon; // Cache small integers
647 return lcon;
648 }
650 //------------------------------zerocon-----------------------------------------
651 // Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
652 ConNode* PhaseTransform::zerocon(BasicType bt) {
653 assert((uint)bt <= _zcon_max, "domain check");
654 ConNode* zcon = _zcons[bt];
655 if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
656 return zcon;
657 zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
658 _zcons[bt] = zcon;
659 return zcon;
660 }
664 //=============================================================================
665 //------------------------------transform--------------------------------------
666 // Return a node which computes the same function as this node, but in a
667 // faster or cheaper fashion.
668 Node *PhaseGVN::transform( Node *n ) {
669 return transform_no_reclaim(n);
670 }
672 //------------------------------transform--------------------------------------
673 // Return a node which computes the same function as this node, but
674 // in a faster or cheaper fashion.
675 Node *PhaseGVN::transform_no_reclaim( Node *n ) {
676 NOT_PRODUCT( set_transforms(); )
678 // Apply the Ideal call in a loop until it no longer applies
679 Node *k = n;
680 NOT_PRODUCT( uint loop_count = 0; )
681 while( 1 ) {
682 Node *i = k->Ideal(this, /*can_reshape=*/false);
683 if( !i ) break;
684 assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
685 k = i;
686 assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
687 }
688 NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
691 // If brand new node, make space in type array.
692 ensure_type_or_null(k);
694 // Since I just called 'Value' to compute the set of run-time values
695 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
696 // cache Value. Later requests for the local phase->type of this Node can
697 // use the cached Value instead of suffering with 'bottom_type'.
698 const Type *t = k->Value(this); // Get runtime Value set
699 assert(t != NULL, "value sanity");
700 if (type_or_null(k) != t) {
701 #ifndef PRODUCT
702 // Do not count initial visit to node as a transformation
703 if (type_or_null(k) == NULL) {
704 inc_new_values();
705 set_progress();
706 }
707 #endif
708 set_type(k, t);
709 // If k is a TypeNode, capture any more-precise type permanently into Node
710 k->raise_bottom_type(t);
711 }
713 if( t->singleton() && !k->is_Con() ) {
714 NOT_PRODUCT( set_progress(); )
715 return makecon(t); // Turn into a constant
716 }
718 // Now check for Identities
719 Node *i = k->Identity(this); // Look for a nearby replacement
720 if( i != k ) { // Found? Return replacement!
721 NOT_PRODUCT( set_progress(); )
722 return i;
723 }
725 // Global Value Numbering
726 i = hash_find_insert(k); // Insert if new
727 if( i && (i != k) ) {
728 // Return the pre-existing node
729 NOT_PRODUCT( set_progress(); )
730 return i;
731 }
733 // Return Idealized original
734 return k;
735 }
737 #ifdef ASSERT
738 //------------------------------dead_loop_check--------------------------------
739 // Check for a simple dead loop when a data node references itself directly
740 // or through an other data node excluding cons and phis.
741 void PhaseGVN::dead_loop_check( Node *n ) {
742 // Phi may reference itself in a loop
743 if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
744 // Do 2 levels check and only data inputs.
745 bool no_dead_loop = true;
746 uint cnt = n->req();
747 for (uint i = 1; i < cnt && no_dead_loop; i++) {
748 Node *in = n->in(i);
749 if (in == n) {
750 no_dead_loop = false;
751 } else if (in != NULL && !in->is_dead_loop_safe()) {
752 uint icnt = in->req();
753 for (uint j = 1; j < icnt && no_dead_loop; j++) {
754 if (in->in(j) == n || in->in(j) == in)
755 no_dead_loop = false;
756 }
757 }
758 }
759 if (!no_dead_loop) n->dump(3);
760 assert(no_dead_loop, "dead loop detected");
761 }
762 }
763 #endif
765 //=============================================================================
766 //------------------------------PhaseIterGVN-----------------------------------
767 // Initialize hash table to fresh and clean for +VerifyOpto
768 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ),
769 _stack(C->unique() >> 1),
770 _delay_transform(false) {
771 }
773 //------------------------------PhaseIterGVN-----------------------------------
774 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
775 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
776 _worklist( igvn->_worklist ),
777 _stack( igvn->_stack ),
778 _delay_transform(igvn->_delay_transform)
779 {
780 }
782 //------------------------------PhaseIterGVN-----------------------------------
783 // Initialize with previous PhaseGVN info from Parser
784 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
785 _worklist(*C->for_igvn()),
786 _stack(C->unique() >> 1),
787 _delay_transform(false)
788 {
789 uint max;
791 // Dead nodes in the hash table inherited from GVN were not treated as
792 // roots during def-use info creation; hence they represent an invisible
793 // use. Clear them out.
794 max = _table.size();
795 for( uint i = 0; i < max; ++i ) {
796 Node *n = _table.at(i);
797 if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
798 if( n->is_top() ) continue;
799 assert( false, "Parse::remove_useless_nodes missed this node");
800 hash_delete(n);
801 }
802 }
804 // Any Phis or Regions on the worklist probably had uses that could not
805 // make more progress because the uses were made while the Phis and Regions
806 // were in half-built states. Put all uses of Phis and Regions on worklist.
807 max = _worklist.size();
808 for( uint j = 0; j < max; j++ ) {
809 Node *n = _worklist.at(j);
810 uint uop = n->Opcode();
811 if( uop == Op_Phi || uop == Op_Region ||
812 n->is_Type() ||
813 n->is_Mem() )
814 add_users_to_worklist(n);
815 }
816 }
819 #ifndef PRODUCT
820 void PhaseIterGVN::verify_step(Node* n) {
821 _verify_window[_verify_counter % _verify_window_size] = n;
822 ++_verify_counter;
823 ResourceMark rm;
824 ResourceArea *area = Thread::current()->resource_area();
825 VectorSet old_space(area), new_space(area);
826 if (C->unique() < 1000 ||
827 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
828 ++_verify_full_passes;
829 Node::verify_recur(C->root(), -1, old_space, new_space);
830 }
831 const int verify_depth = 4;
832 for ( int i = 0; i < _verify_window_size; i++ ) {
833 Node* n = _verify_window[i];
834 if ( n == NULL ) continue;
835 if( n->in(0) == NodeSentinel ) { // xform_idom
836 _verify_window[i] = n->in(1);
837 --i; continue;
838 }
839 // Typical fanout is 1-2, so this call visits about 6 nodes.
840 Node::verify_recur(n, verify_depth, old_space, new_space);
841 }
842 }
843 #endif
846 //------------------------------init_worklist----------------------------------
847 // Initialize worklist for each node.
848 void PhaseIterGVN::init_worklist( Node *n ) {
849 if( _worklist.member(n) ) return;
850 _worklist.push(n);
851 uint cnt = n->req();
852 for( uint i =0 ; i < cnt; i++ ) {
853 Node *m = n->in(i);
854 if( m ) init_worklist(m);
855 }
856 }
858 //------------------------------optimize---------------------------------------
859 void PhaseIterGVN::optimize() {
860 debug_only(uint num_processed = 0;);
861 #ifndef PRODUCT
862 {
863 _verify_counter = 0;
864 _verify_full_passes = 0;
865 for ( int i = 0; i < _verify_window_size; i++ ) {
866 _verify_window[i] = NULL;
867 }
868 }
869 #endif
871 #ifdef ASSERT
872 Node* prev = NULL;
873 uint rep_cnt = 0;
874 #endif
875 uint loop_count = 0;
877 // Pull from worklist; transform node;
878 // If node has changed: update edge info and put uses on worklist.
879 while( _worklist.size() ) {
880 if (C->check_node_count(NodeLimitFudgeFactor * 2,
881 "out of nodes optimizing method")) {
882 return;
883 }
884 Node *n = _worklist.pop();
885 if (++loop_count >= K * C->unique()) {
886 debug_only(n->dump(4);)
887 assert(false, "infinite loop in PhaseIterGVN::optimize");
888 C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
889 return;
890 }
891 #ifdef ASSERT
892 if (n == prev) {
893 if (++rep_cnt > 3) {
894 n->dump(4);
895 assert(false, "loop in Ideal transformation");
896 }
897 } else {
898 rep_cnt = 0;
899 }
900 prev = n;
901 #endif
902 if (TraceIterativeGVN && Verbose) {
903 tty->print(" Pop ");
904 NOT_PRODUCT( n->dump(); )
905 debug_only(if( (num_processed++ % 100) == 0 ) _worklist.print_set();)
906 }
908 if (n->outcnt() != 0) {
910 #ifndef PRODUCT
911 uint wlsize = _worklist.size();
912 const Type* oldtype = type_or_null(n);
913 #endif //PRODUCT
915 Node *nn = transform_old(n);
917 #ifndef PRODUCT
918 if (TraceIterativeGVN) {
919 const Type* newtype = type_or_null(n);
920 if (nn != n) {
921 // print old node
922 tty->print("< ");
923 if (oldtype != newtype && oldtype != NULL) {
924 oldtype->dump();
925 }
926 do { tty->print("\t"); } while (tty->position() < 16);
927 tty->print("<");
928 n->dump();
929 }
930 if (oldtype != newtype || nn != n) {
931 // print new node and/or new type
932 if (oldtype == NULL) {
933 tty->print("* ");
934 } else if (nn != n) {
935 tty->print("> ");
936 } else {
937 tty->print("= ");
938 }
939 if (newtype == NULL) {
940 tty->print("null");
941 } else {
942 newtype->dump();
943 }
944 do { tty->print("\t"); } while (tty->position() < 16);
945 nn->dump();
946 }
947 if (Verbose && wlsize < _worklist.size()) {
948 tty->print(" Push {");
949 while (wlsize != _worklist.size()) {
950 Node* pushed = _worklist.at(wlsize++);
951 tty->print(" %d", pushed->_idx);
952 }
953 tty->print_cr(" }");
954 }
955 }
956 if( VerifyIterativeGVN && nn != n ) {
957 verify_step((Node*) NULL); // ignore n, it might be subsumed
958 }
959 #endif
960 } else if (!n->is_top()) {
961 remove_dead_node(n);
962 }
963 }
965 #ifndef PRODUCT
966 C->verify_graph_edges();
967 if( VerifyOpto && allow_progress() ) {
968 // Must turn off allow_progress to enable assert and break recursion
969 C->root()->verify();
970 { // Check if any progress was missed using IterGVN
971 // Def-Use info enables transformations not attempted in wash-pass
972 // e.g. Region/Phi cleanup, ...
973 // Null-check elision -- may not have reached fixpoint
974 // do not propagate to dominated nodes
975 ResourceMark rm;
976 PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
977 // Fill worklist completely
978 igvn2.init_worklist(C->root());
980 igvn2.set_allow_progress(false);
981 igvn2.optimize();
982 igvn2.set_allow_progress(true);
983 }
984 }
985 if ( VerifyIterativeGVN && PrintOpto ) {
986 if ( _verify_counter == _verify_full_passes )
987 tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
988 _verify_full_passes);
989 else
990 tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
991 _verify_counter, _verify_full_passes);
992 }
993 #endif
994 }
997 //------------------register_new_node_with_optimizer---------------------------
998 // Register a new node with the optimizer. Update the types array, the def-use
999 // info. Put on worklist.
1000 Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1001 set_type_bottom(n);
1002 _worklist.push(n);
1003 if (orig != NULL) C->copy_node_notes_to(n, orig);
1004 return n;
1005 }
1007 //------------------------------transform--------------------------------------
1008 // Non-recursive: idealize Node 'n' with respect to its inputs and its value
1009 Node *PhaseIterGVN::transform( Node *n ) {
1010 if (_delay_transform) {
1011 // Register the node but don't optimize for now
1012 register_new_node_with_optimizer(n);
1013 return n;
1014 }
1016 // If brand new node, make space in type array, and give it a type.
1017 ensure_type_or_null(n);
1018 if (type_or_null(n) == NULL) {
1019 set_type_bottom(n);
1020 }
1022 return transform_old(n);
1023 }
1025 //------------------------------transform_old----------------------------------
1026 Node *PhaseIterGVN::transform_old( Node *n ) {
1027 #ifndef PRODUCT
1028 debug_only(uint loop_count = 0;);
1029 set_transforms();
1030 #endif
1031 // Remove 'n' from hash table in case it gets modified
1032 _table.hash_delete(n);
1033 if( VerifyIterativeGVN ) {
1034 assert( !_table.find_index(n->_idx), "found duplicate entry in table");
1035 }
1037 // Apply the Ideal call in a loop until it no longer applies
1038 Node *k = n;
1039 DEBUG_ONLY(dead_loop_check(k);)
1040 DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1041 Node *i = k->Ideal(this, /*can_reshape=*/true);
1042 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1043 #ifndef PRODUCT
1044 if( VerifyIterativeGVN )
1045 verify_step(k);
1046 if( i && VerifyOpto ) {
1047 if( !allow_progress() ) {
1048 if (i->is_Add() && i->outcnt() == 1) {
1049 // Switched input to left side because this is the only use
1050 } else if( i->is_If() && (i->in(0) == NULL) ) {
1051 // This IF is dead because it is dominated by an equivalent IF When
1052 // dominating if changed, info is not propagated sparsely to 'this'
1053 // Propagating this info further will spuriously identify other
1054 // progress.
1055 return i;
1056 } else
1057 set_progress();
1058 } else
1059 set_progress();
1060 }
1061 #endif
1063 while( i ) {
1064 #ifndef PRODUCT
1065 debug_only( if( loop_count >= K ) i->dump(4); )
1066 assert(loop_count < K, "infinite loop in PhaseIterGVN::transform");
1067 debug_only( loop_count++; )
1068 #endif
1069 assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1070 // Made a change; put users of original Node on worklist
1071 add_users_to_worklist( k );
1072 // Replacing root of transform tree?
1073 if( k != i ) {
1074 // Make users of old Node now use new.
1075 subsume_node( k, i );
1076 k = i;
1077 }
1078 DEBUG_ONLY(dead_loop_check(k);)
1079 // Try idealizing again
1080 DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1081 i = k->Ideal(this, /*can_reshape=*/true);
1082 assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1083 #ifndef PRODUCT
1084 if( VerifyIterativeGVN )
1085 verify_step(k);
1086 if( i && VerifyOpto ) set_progress();
1087 #endif
1088 }
1090 // If brand new node, make space in type array.
1091 ensure_type_or_null(k);
1093 // See what kind of values 'k' takes on at runtime
1094 const Type *t = k->Value(this);
1095 assert(t != NULL, "value sanity");
1097 // Since I just called 'Value' to compute the set of run-time values
1098 // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1099 // cache Value. Later requests for the local phase->type of this Node can
1100 // use the cached Value instead of suffering with 'bottom_type'.
1101 if (t != type_or_null(k)) {
1102 NOT_PRODUCT( set_progress(); )
1103 NOT_PRODUCT( inc_new_values();)
1104 set_type(k, t);
1105 // If k is a TypeNode, capture any more-precise type permanently into Node
1106 k->raise_bottom_type(t);
1107 // Move users of node to worklist
1108 add_users_to_worklist( k );
1109 }
1111 // If 'k' computes a constant, replace it with a constant
1112 if( t->singleton() && !k->is_Con() ) {
1113 NOT_PRODUCT( set_progress(); )
1114 Node *con = makecon(t); // Make a constant
1115 add_users_to_worklist( k );
1116 subsume_node( k, con ); // Everybody using k now uses con
1117 return con;
1118 }
1120 // Now check for Identities
1121 i = k->Identity(this); // Look for a nearby replacement
1122 if( i != k ) { // Found? Return replacement!
1123 NOT_PRODUCT( set_progress(); )
1124 add_users_to_worklist( k );
1125 subsume_node( k, i ); // Everybody using k now uses i
1126 return i;
1127 }
1129 // Global Value Numbering
1130 i = hash_find_insert(k); // Check for pre-existing node
1131 if( i && (i != k) ) {
1132 // Return the pre-existing node if it isn't dead
1133 NOT_PRODUCT( set_progress(); )
1134 add_users_to_worklist( k );
1135 subsume_node( k, i ); // Everybody using k now uses i
1136 return i;
1137 }
1139 // Return Idealized original
1140 return k;
1141 }
1143 //---------------------------------saturate------------------------------------
1144 const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1145 const Type* limit_type) const {
1146 return new_type->narrow(old_type);
1147 }
1149 //------------------------------remove_globally_dead_node----------------------
1150 // Kill a globally dead Node. All uses are also globally dead and are
1151 // aggressively trimmed.
1152 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1153 enum DeleteProgress {
1154 PROCESS_INPUTS,
1155 PROCESS_OUTPUTS
1156 };
1157 assert(_stack.is_empty(), "not empty");
1158 _stack.push(dead, PROCESS_INPUTS);
1160 while (_stack.is_nonempty()) {
1161 dead = _stack.node();
1162 uint progress_state = _stack.index();
1163 assert(dead != C->root(), "killing root, eh?");
1164 assert(!dead->is_top(), "add check for top when pushing");
1165 NOT_PRODUCT( set_progress(); )
1166 if (progress_state == PROCESS_INPUTS) {
1167 // After following inputs, continue to outputs
1168 _stack.set_index(PROCESS_OUTPUTS);
1169 // Remove from iterative worklist
1170 _worklist.remove(dead);
1171 if (!dead->is_Con()) { // Don't kill cons but uses
1172 bool recurse = false;
1173 // Remove from hash table
1174 _table.hash_delete( dead );
1175 // Smash all inputs to 'dead', isolating him completely
1176 for( uint i = 0; i < dead->req(); i++ ) {
1177 Node *in = dead->in(i);
1178 if( in ) { // Points to something?
1179 dead->set_req(i,NULL); // Kill the edge
1180 if (in->outcnt() == 0 && in != C->top()) {// Made input go dead?
1181 _stack.push(in, PROCESS_INPUTS); // Recursively remove
1182 recurse = true;
1183 } else if (in->outcnt() == 1 &&
1184 in->has_special_unique_user()) {
1185 _worklist.push(in->unique_out());
1186 } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1187 if( in->Opcode() == Op_Region )
1188 _worklist.push(in);
1189 else if( in->is_Store() ) {
1190 DUIterator_Fast imax, i = in->fast_outs(imax);
1191 _worklist.push(in->fast_out(i));
1192 i++;
1193 if(in->outcnt() == 2) {
1194 _worklist.push(in->fast_out(i));
1195 i++;
1196 }
1197 assert(!(i < imax), "sanity");
1198 }
1199 }
1200 if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory &&
1201 in->is_Proj() && in->in(0) != NULL && in->in(0)->is_Initialize()) {
1202 // A Load that directly follows an InitializeNode is
1203 // going away. The Stores that follow are candidates
1204 // again to be captured by the InitializeNode.
1205 for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) {
1206 Node *n = in->fast_out(j);
1207 if (n->is_Store()) {
1208 _worklist.push(n);
1209 }
1210 }
1211 }
1212 }
1213 }
1214 C->record_dead_node(dead->_idx);
1215 if (dead->is_macro()) {
1216 C->remove_macro_node(dead);
1217 }
1218 if (dead->is_expensive()) {
1219 C->remove_expensive_node(dead);
1220 }
1222 if (recurse) {
1223 continue;
1224 }
1225 }
1226 // Constant node that has no out-edges and has only one in-edge from
1227 // root is usually dead. However, sometimes reshaping walk makes
1228 // it reachable by adding use edges. So, we will NOT count Con nodes
1229 // as dead to be conservative about the dead node count at any
1230 // given time.
1231 }
1233 // Aggressively kill globally dead uses
1234 // (Rather than pushing all the outs at once, we push one at a time,
1235 // plus the parent to resume later, because of the indefinite number
1236 // of edge deletions per loop trip.)
1237 if (dead->outcnt() > 0) {
1238 // Recursively remove
1239 _stack.push(dead->raw_out(0), PROCESS_INPUTS);
1240 } else {
1241 _stack.pop();
1242 }
1243 }
1244 }
1246 //------------------------------subsume_node-----------------------------------
1247 // Remove users from node 'old' and add them to node 'nn'.
1248 void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1249 assert( old != hash_find(old), "should already been removed" );
1250 assert( old != C->top(), "cannot subsume top node");
1251 // Copy debug or profile information to the new version:
1252 C->copy_node_notes_to(nn, old);
1253 // Move users of node 'old' to node 'nn'
1254 for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1255 Node* use = old->last_out(i); // for each use...
1256 // use might need re-hashing (but it won't if it's a new node)
1257 bool is_in_table = _table.hash_delete( use );
1258 // Update use-def info as well
1259 // We remove all occurrences of old within use->in,
1260 // so as to avoid rehashing any node more than once.
1261 // The hash table probe swamps any outer loop overhead.
1262 uint num_edges = 0;
1263 for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1264 if (use->in(j) == old) {
1265 use->set_req(j, nn);
1266 ++num_edges;
1267 }
1268 }
1269 // Insert into GVN hash table if unique
1270 // If a duplicate, 'use' will be cleaned up when pulled off worklist
1271 if( is_in_table ) {
1272 hash_find_insert(use);
1273 }
1274 i -= num_edges; // we deleted 1 or more copies of this edge
1275 }
1277 // Smash all inputs to 'old', isolating him completely
1278 Node *temp = new (C) Node(1);
1279 temp->init_req(0,nn); // Add a use to nn to prevent him from dying
1280 remove_dead_node( old );
1281 temp->del_req(0); // Yank bogus edge
1282 #ifndef PRODUCT
1283 if( VerifyIterativeGVN ) {
1284 for ( int i = 0; i < _verify_window_size; i++ ) {
1285 if ( _verify_window[i] == old )
1286 _verify_window[i] = nn;
1287 }
1288 }
1289 #endif
1290 _worklist.remove(temp); // this can be necessary
1291 temp->destruct(); // reuse the _idx of this little guy
1292 }
1294 //------------------------------add_users_to_worklist--------------------------
1295 void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
1296 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1297 _worklist.push(n->fast_out(i)); // Push on worklist
1298 }
1299 }
1301 void PhaseIterGVN::add_users_to_worklist( Node *n ) {
1302 add_users_to_worklist0(n);
1304 // Move users of node to worklist
1305 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1306 Node* use = n->fast_out(i); // Get use
1308 if( use->is_Multi() || // Multi-definer? Push projs on worklist
1309 use->is_Store() ) // Enable store/load same address
1310 add_users_to_worklist0(use);
1312 // If we changed the receiver type to a call, we need to revisit
1313 // the Catch following the call. It's looking for a non-NULL
1314 // receiver to know when to enable the regular fall-through path
1315 // in addition to the NullPtrException path.
1316 if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1317 Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
1318 if (p != NULL) {
1319 add_users_to_worklist0(p);
1320 }
1321 }
1323 if( use->is_Cmp() ) { // Enable CMP/BOOL optimization
1324 add_users_to_worklist(use); // Put Bool on worklist
1325 // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1326 // phi merging either 0 or 1 onto the worklist
1327 if (use->outcnt() > 0) {
1328 Node* bol = use->raw_out(0);
1329 if (bol->outcnt() > 0) {
1330 Node* iff = bol->raw_out(0);
1331 if (iff->outcnt() == 2) {
1332 Node* ifproj0 = iff->raw_out(0);
1333 Node* ifproj1 = iff->raw_out(1);
1334 if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1335 Node* region0 = ifproj0->raw_out(0);
1336 Node* region1 = ifproj1->raw_out(0);
1337 if( region0 == region1 )
1338 add_users_to_worklist0(region0);
1339 }
1340 }
1341 }
1342 }
1343 }
1345 uint use_op = use->Opcode();
1346 // If changed Cast input, check Phi users for simple cycles
1347 if( use->is_ConstraintCast() || use->is_CheckCastPP() ) {
1348 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1349 Node* u = use->fast_out(i2);
1350 if (u->is_Phi())
1351 _worklist.push(u);
1352 }
1353 }
1354 // If changed LShift inputs, check RShift users for useless sign-ext
1355 if( use_op == Op_LShiftI ) {
1356 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1357 Node* u = use->fast_out(i2);
1358 if (u->Opcode() == Op_RShiftI)
1359 _worklist.push(u);
1360 }
1361 }
1362 // If changed AddP inputs, check Stores for loop invariant
1363 if( use_op == Op_AddP ) {
1364 for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1365 Node* u = use->fast_out(i2);
1366 if (u->is_Mem())
1367 _worklist.push(u);
1368 }
1369 }
1370 // If changed initialization activity, check dependent Stores
1371 if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1372 InitializeNode* init = use->as_Allocate()->initialization();
1373 if (init != NULL) {
1374 Node* imem = init->proj_out(TypeFunc::Memory);
1375 if (imem != NULL) add_users_to_worklist0(imem);
1376 }
1377 }
1378 if (use_op == Op_Initialize) {
1379 Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
1380 if (imem != NULL) add_users_to_worklist0(imem);
1381 }
1382 }
1383 }
1385 //=============================================================================
1386 #ifndef PRODUCT
1387 uint PhaseCCP::_total_invokes = 0;
1388 uint PhaseCCP::_total_constants = 0;
1389 #endif
1390 //------------------------------PhaseCCP---------------------------------------
1391 // Conditional Constant Propagation, ala Wegman & Zadeck
1392 PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1393 NOT_PRODUCT( clear_constants(); )
1394 assert( _worklist.size() == 0, "" );
1395 // Clear out _nodes from IterGVN. Must be clear to transform call.
1396 _nodes.clear(); // Clear out from IterGVN
1397 analyze();
1398 }
1400 #ifndef PRODUCT
1401 //------------------------------~PhaseCCP--------------------------------------
1402 PhaseCCP::~PhaseCCP() {
1403 inc_invokes();
1404 _total_constants += count_constants();
1405 }
1406 #endif
1409 #ifdef ASSERT
1410 static bool ccp_type_widens(const Type* t, const Type* t0) {
1411 assert(t->meet(t0) == t, "Not monotonic");
1412 switch (t->base() == t0->base() ? t->base() : Type::Top) {
1413 case Type::Int:
1414 assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
1415 break;
1416 case Type::Long:
1417 assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
1418 break;
1419 }
1420 return true;
1421 }
1422 #endif //ASSERT
1424 //------------------------------analyze----------------------------------------
1425 void PhaseCCP::analyze() {
1426 // Initialize all types to TOP, optimistic analysis
1427 for (int i = C->unique() - 1; i >= 0; i--) {
1428 _types.map(i,Type::TOP);
1429 }
1431 // Push root onto worklist
1432 Unique_Node_List worklist;
1433 worklist.push(C->root());
1435 // Pull from worklist; compute new value; push changes out.
1436 // This loop is the meat of CCP.
1437 while( worklist.size() ) {
1438 Node *n = worklist.pop();
1439 const Type *t = n->Value(this);
1440 if (t != type(n)) {
1441 assert(ccp_type_widens(t, type(n)), "ccp type must widen");
1442 #ifndef PRODUCT
1443 if( TracePhaseCCP ) {
1444 t->dump();
1445 do { tty->print("\t"); } while (tty->position() < 16);
1446 n->dump();
1447 }
1448 #endif
1449 set_type(n, t);
1450 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1451 Node* m = n->fast_out(i); // Get user
1452 if( m->is_Region() ) { // New path to Region? Must recheck Phis too
1453 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1454 Node* p = m->fast_out(i2); // Propagate changes to uses
1455 if( p->bottom_type() != type(p) ) // If not already bottomed out
1456 worklist.push(p); // Propagate change to user
1457 }
1458 }
1459 // If we changed the receiver type to a call, we need to revisit
1460 // the Catch following the call. It's looking for a non-NULL
1461 // receiver to know when to enable the regular fall-through path
1462 // in addition to the NullPtrException path
1463 if (m->is_Call()) {
1464 for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
1465 Node* p = m->fast_out(i2); // Propagate changes to uses
1466 if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1)
1467 worklist.push(p->unique_out());
1468 }
1469 }
1470 if( m->bottom_type() != type(m) ) // If not already bottomed out
1471 worklist.push(m); // Propagate change to user
1472 }
1473 }
1474 }
1475 }
1477 //------------------------------do_transform-----------------------------------
1478 // Top level driver for the recursive transformer
1479 void PhaseCCP::do_transform() {
1480 // Correct leaves of new-space Nodes; they point to old-space.
1481 C->set_root( transform(C->root())->as_Root() );
1482 assert( C->top(), "missing TOP node" );
1483 assert( C->root(), "missing root" );
1484 }
1486 //------------------------------transform--------------------------------------
1487 // Given a Node in old-space, clone him into new-space.
1488 // Convert any of his old-space children into new-space children.
1489 Node *PhaseCCP::transform( Node *n ) {
1490 Node *new_node = _nodes[n->_idx]; // Check for transformed node
1491 if( new_node != NULL )
1492 return new_node; // Been there, done that, return old answer
1493 new_node = transform_once(n); // Check for constant
1494 _nodes.map( n->_idx, new_node ); // Flag as having been cloned
1496 // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
1497 GrowableArray <Node *> trstack(C->unique() >> 1);
1499 trstack.push(new_node); // Process children of cloned node
1500 while ( trstack.is_nonempty() ) {
1501 Node *clone = trstack.pop();
1502 uint cnt = clone->req();
1503 for( uint i = 0; i < cnt; i++ ) { // For all inputs do
1504 Node *input = clone->in(i);
1505 if( input != NULL ) { // Ignore NULLs
1506 Node *new_input = _nodes[input->_idx]; // Check for cloned input node
1507 if( new_input == NULL ) {
1508 new_input = transform_once(input); // Check for constant
1509 _nodes.map( input->_idx, new_input );// Flag as having been cloned
1510 trstack.push(new_input);
1511 }
1512 assert( new_input == clone->in(i), "insanity check");
1513 }
1514 }
1515 }
1516 return new_node;
1517 }
1520 //------------------------------transform_once---------------------------------
1521 // For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
1522 Node *PhaseCCP::transform_once( Node *n ) {
1523 const Type *t = type(n);
1524 // Constant? Use constant Node instead
1525 if( t->singleton() ) {
1526 Node *nn = n; // Default is to return the original constant
1527 if( t == Type::TOP ) {
1528 // cache my top node on the Compile instance
1529 if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
1530 C->set_cached_top_node( ConNode::make(C, Type::TOP) );
1531 set_type(C->top(), Type::TOP);
1532 }
1533 nn = C->top();
1534 }
1535 if( !n->is_Con() ) {
1536 if( t != Type::TOP ) {
1537 nn = makecon(t); // ConNode::make(t);
1538 NOT_PRODUCT( inc_constants(); )
1539 } else if( n->is_Region() ) { // Unreachable region
1540 // Note: nn == C->top()
1541 n->set_req(0, NULL); // Cut selfreference
1542 // Eagerly remove dead phis to avoid phis copies creation.
1543 for (DUIterator i = n->outs(); n->has_out(i); i++) {
1544 Node* m = n->out(i);
1545 if( m->is_Phi() ) {
1546 assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
1547 replace_node(m, nn);
1548 --i; // deleted this phi; rescan starting with next position
1549 }
1550 }
1551 }
1552 replace_node(n,nn); // Update DefUse edges for new constant
1553 }
1554 return nn;
1555 }
1557 // If x is a TypeNode, capture any more-precise type permanently into Node
1558 if (t != n->bottom_type()) {
1559 hash_delete(n); // changing bottom type may force a rehash
1560 n->raise_bottom_type(t);
1561 _worklist.push(n); // n re-enters the hash table via the worklist
1562 }
1564 // Idealize graph using DU info. Must clone() into new-space.
1565 // DU info is generally used to show profitability, progress or safety
1566 // (but generally not needed for correctness).
1567 Node *nn = n->Ideal_DU_postCCP(this);
1569 // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
1570 switch( n->Opcode() ) {
1571 case Op_FastLock: // Revisit FastLocks for lock coarsening
1572 case Op_If:
1573 case Op_CountedLoopEnd:
1574 case Op_Region:
1575 case Op_Loop:
1576 case Op_CountedLoop:
1577 case Op_Conv2B:
1578 case Op_Opaque1:
1579 case Op_Opaque2:
1580 _worklist.push(n);
1581 break;
1582 default:
1583 break;
1584 }
1585 if( nn ) {
1586 _worklist.push(n);
1587 // Put users of 'n' onto worklist for second igvn transform
1588 add_users_to_worklist(n);
1589 return nn;
1590 }
1592 return n;
1593 }
1595 //---------------------------------saturate------------------------------------
1596 const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
1597 const Type* limit_type) const {
1598 const Type* wide_type = new_type->widen(old_type, limit_type);
1599 if (wide_type != new_type) { // did we widen?
1600 // If so, we may have widened beyond the limit type. Clip it back down.
1601 new_type = wide_type->filter(limit_type);
1602 }
1603 return new_type;
1604 }
1606 //------------------------------print_statistics-------------------------------
1607 #ifndef PRODUCT
1608 void PhaseCCP::print_statistics() {
1609 tty->print_cr("CCP: %d constants found: %d", _total_invokes, _total_constants);
1610 }
1611 #endif
1614 //=============================================================================
1615 #ifndef PRODUCT
1616 uint PhasePeephole::_total_peepholes = 0;
1617 #endif
1618 //------------------------------PhasePeephole----------------------------------
1619 // Conditional Constant Propagation, ala Wegman & Zadeck
1620 PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
1621 : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
1622 NOT_PRODUCT( clear_peepholes(); )
1623 }
1625 #ifndef PRODUCT
1626 //------------------------------~PhasePeephole---------------------------------
1627 PhasePeephole::~PhasePeephole() {
1628 _total_peepholes += count_peepholes();
1629 }
1630 #endif
1632 //------------------------------transform--------------------------------------
1633 Node *PhasePeephole::transform( Node *n ) {
1634 ShouldNotCallThis();
1635 return NULL;
1636 }
1638 //------------------------------do_transform-----------------------------------
1639 void PhasePeephole::do_transform() {
1640 bool method_name_not_printed = true;
1642 // Examine each basic block
1643 for( uint block_number = 1; block_number < _cfg._num_blocks; ++block_number ) {
1644 Block *block = _cfg._blocks[block_number];
1645 bool block_not_printed = true;
1647 // and each instruction within a block
1648 uint end_index = block->_nodes.size();
1649 // block->end_idx() not valid after PhaseRegAlloc
1650 for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
1651 Node *n = block->_nodes.at(instruction_index);
1652 if( n->is_Mach() ) {
1653 MachNode *m = n->as_Mach();
1654 int deleted_count = 0;
1655 // check for peephole opportunities
1656 MachNode *m2 = m->peephole( block, instruction_index, _regalloc, deleted_count, C );
1657 if( m2 != NULL ) {
1658 #ifndef PRODUCT
1659 if( PrintOptoPeephole ) {
1660 // Print method, first time only
1661 if( C->method() && method_name_not_printed ) {
1662 C->method()->print_short_name(); tty->cr();
1663 method_name_not_printed = false;
1664 }
1665 // Print this block
1666 if( Verbose && block_not_printed) {
1667 tty->print_cr("in block");
1668 block->dump();
1669 block_not_printed = false;
1670 }
1671 // Print instructions being deleted
1672 for( int i = (deleted_count - 1); i >= 0; --i ) {
1673 block->_nodes.at(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
1674 }
1675 tty->print_cr("replaced with");
1676 // Print new instruction
1677 m2->format(_regalloc);
1678 tty->print("\n\n");
1679 }
1680 #endif
1681 // Remove old nodes from basic block and update instruction_index
1682 // (old nodes still exist and may have edges pointing to them
1683 // as register allocation info is stored in the allocator using
1684 // the node index to live range mappings.)
1685 uint safe_instruction_index = (instruction_index - deleted_count);
1686 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
1687 block->_nodes.remove( instruction_index );
1688 }
1689 // install new node after safe_instruction_index
1690 block->_nodes.insert( safe_instruction_index + 1, m2 );
1691 end_index = block->_nodes.size() - 1; // Recompute new block size
1692 NOT_PRODUCT( inc_peepholes(); )
1693 }
1694 }
1695 }
1696 }
1697 }
1699 //------------------------------print_statistics-------------------------------
1700 #ifndef PRODUCT
1701 void PhasePeephole::print_statistics() {
1702 tty->print_cr("Peephole: peephole rules applied: %d", _total_peepholes);
1703 }
1704 #endif
1707 //=============================================================================
1708 //------------------------------set_req_X--------------------------------------
1709 void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
1710 assert( is_not_dead(n), "can not use dead node");
1711 assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
1712 Node *old = in(i);
1713 set_req(i, n);
1715 // old goes dead?
1716 if( old ) {
1717 switch (old->outcnt()) {
1718 case 0:
1719 // Put into the worklist to kill later. We do not kill it now because the
1720 // recursive kill will delete the current node (this) if dead-loop exists
1721 if (!old->is_top())
1722 igvn->_worklist.push( old );
1723 break;
1724 case 1:
1725 if( old->is_Store() || old->has_special_unique_user() )
1726 igvn->add_users_to_worklist( old );
1727 break;
1728 case 2:
1729 if( old->is_Store() )
1730 igvn->add_users_to_worklist( old );
1731 if( old->Opcode() == Op_Region )
1732 igvn->_worklist.push(old);
1733 break;
1734 case 3:
1735 if( old->Opcode() == Op_Region ) {
1736 igvn->_worklist.push(old);
1737 igvn->add_users_to_worklist( old );
1738 }
1739 break;
1740 default:
1741 break;
1742 }
1743 }
1745 }
1747 //-------------------------------replace_by-----------------------------------
1748 // Using def-use info, replace one node for another. Follow the def-use info
1749 // to all users of the OLD node. Then make all uses point to the NEW node.
1750 void Node::replace_by(Node *new_node) {
1751 assert(!is_top(), "top node has no DU info");
1752 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
1753 Node* use = last_out(i);
1754 uint uses_found = 0;
1755 for (uint j = 0; j < use->len(); j++) {
1756 if (use->in(j) == this) {
1757 if (j < use->req())
1758 use->set_req(j, new_node);
1759 else use->set_prec(j, new_node);
1760 uses_found++;
1761 }
1762 }
1763 i -= uses_found; // we deleted 1 or more copies of this edge
1764 }
1765 }
1767 //=============================================================================
1768 //-----------------------------------------------------------------------------
1769 void Type_Array::grow( uint i ) {
1770 if( !_max ) {
1771 _max = 1;
1772 _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
1773 _types[0] = NULL;
1774 }
1775 uint old = _max;
1776 while( i >= _max ) _max <<= 1; // Double to fit
1777 _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
1778 memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
1779 }
1781 //------------------------------dump-------------------------------------------
1782 #ifndef PRODUCT
1783 void Type_Array::dump() const {
1784 uint max = Size();
1785 for( uint i = 0; i < max; i++ ) {
1786 if( _types[i] != NULL ) {
1787 tty->print(" %d\t== ", i); _types[i]->dump(); tty->cr();
1788 }
1789 }
1790 }
1791 #endif
