1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "libadt/vectset.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "opto/cfgnode.hpp"
29 #include "opto/connode.hpp"
30 #include "opto/loopnode.hpp"
31 #include "opto/machnode.hpp"
32 #include "opto/matcher.hpp"
33 #include "opto/node.hpp"
34 #include "opto/opcodes.hpp"
35 #include "opto/regmask.hpp"
36 #include "opto/type.hpp"
37 #include "utilities/copy.hpp"
38
39 class RegMask;
40 // #include "phase.hpp"
41 class PhaseTransform;
42 class PhaseGVN;
43
44 // Arena we are currently building Nodes in
45 const uint Node::NotAMachineReg = 0xffff0000;
46
47 #ifndef PRODUCT
48 extern int nodes_created;
49 #endif
50
51 #ifdef ASSERT
52
53 //-------------------------- construct_node------------------------------------
54 // Set a breakpoint here to identify where a particular node index is built.
55 void Node::verify_construction() {
56 _debug_orig = NULL;
57 int old_debug_idx = Compile::debug_idx();
58 int new_debug_idx = old_debug_idx+1;
59 if (new_debug_idx > 0) {
60 // Arrange that the lowest five decimal digits of _debug_idx
61 // will repeat those of _idx. In case this is somehow pathological,
62 // we continue to assign negative numbers (!) consecutively.
63 const int mod = 100000;
64 int bump = (int)(_idx - new_debug_idx) % mod;
65 if (bump < 0) bump += mod;
66 assert(bump >= 0 && bump < mod, "");
67 new_debug_idx += bump;
68 }
69 Compile::set_debug_idx(new_debug_idx);
70 set_debug_idx( new_debug_idx );
71 assert(Compile::current()->unique() < (UINT_MAX - 1), "Node limit exceeded UINT_MAX");
72 if (BreakAtNode != 0 && (_debug_idx == BreakAtNode || (int)_idx == BreakAtNode)) {
73 tty->print_cr("BreakAtNode: _idx=%d _debug_idx=%d", _idx, _debug_idx);
74 BREAKPOINT;
75 }
76 #if OPTO_DU_ITERATOR_ASSERT
77 _last_del = NULL;
78 _del_tick = 0;
79 #endif
80 _hash_lock = 0;
81 }
82
83
84 // #ifdef ASSERT ...
85
86 #if OPTO_DU_ITERATOR_ASSERT
87 void DUIterator_Common::sample(const Node* node) {
88 _vdui = VerifyDUIterators;
89 _node = node;
90 _outcnt = node->_outcnt;
91 _del_tick = node->_del_tick;
92 _last = NULL;
93 }
94
95 void DUIterator_Common::verify(const Node* node, bool at_end_ok) {
96 assert(_node == node, "consistent iterator source");
97 assert(_del_tick == node->_del_tick, "no unexpected deletions allowed");
98 }
99
100 void DUIterator_Common::verify_resync() {
101 // Ensure that the loop body has just deleted the last guy produced.
102 const Node* node = _node;
103 // Ensure that at least one copy of the last-seen edge was deleted.
104 // Note: It is OK to delete multiple copies of the last-seen edge.
105 // Unfortunately, we have no way to verify that all the deletions delete
106 // that same edge. On this point we must use the Honor System.
107 assert(node->_del_tick >= _del_tick+1, "must have deleted an edge");
108 assert(node->_last_del == _last, "must have deleted the edge just produced");
109 // We liked this deletion, so accept the resulting outcnt and tick.
110 _outcnt = node->_outcnt;
111 _del_tick = node->_del_tick;
112 }
113
114 void DUIterator_Common::reset(const DUIterator_Common& that) {
115 if (this == &that) return; // ignore assignment to self
116 if (!_vdui) {
117 // We need to initialize everything, overwriting garbage values.
118 _last = that._last;
119 _vdui = that._vdui;
120 }
121 // Note: It is legal (though odd) for an iterator over some node x
122 // to be reassigned to iterate over another node y. Some doubly-nested
123 // progress loops depend on being able to do this.
124 const Node* node = that._node;
125 // Re-initialize everything, except _last.
126 _node = node;
127 _outcnt = node->_outcnt;
128 _del_tick = node->_del_tick;
129 }
130
131 void DUIterator::sample(const Node* node) {
132 DUIterator_Common::sample(node); // Initialize the assertion data.
133 _refresh_tick = 0; // No refreshes have happened, as yet.
134 }
135
136 void DUIterator::verify(const Node* node, bool at_end_ok) {
137 DUIterator_Common::verify(node, at_end_ok);
138 assert(_idx < node->_outcnt + (uint)at_end_ok, "idx in range");
139 }
140
141 void DUIterator::verify_increment() {
142 if (_refresh_tick & 1) {
143 // We have refreshed the index during this loop.
144 // Fix up _idx to meet asserts.
145 if (_idx > _outcnt) _idx = _outcnt;
146 }
147 verify(_node, true);
148 }
149
150 void DUIterator::verify_resync() {
151 // Note: We do not assert on _outcnt, because insertions are OK here.
152 DUIterator_Common::verify_resync();
153 // Make sure we are still in sync, possibly with no more out-edges:
154 verify(_node, true);
155 }
156
157 void DUIterator::reset(const DUIterator& that) {
158 if (this == &that) return; // self assignment is always a no-op
159 assert(that._refresh_tick == 0, "assign only the result of Node::outs()");
160 assert(that._idx == 0, "assign only the result of Node::outs()");
161 assert(_idx == that._idx, "already assigned _idx");
162 if (!_vdui) {
163 // We need to initialize everything, overwriting garbage values.
164 sample(that._node);
165 } else {
166 DUIterator_Common::reset(that);
167 if (_refresh_tick & 1) {
168 _refresh_tick++; // Clear the "was refreshed" flag.
169 }
170 assert(_refresh_tick < 2*100000, "DU iteration must converge quickly");
171 }
172 }
173
174 void DUIterator::refresh() {
175 DUIterator_Common::sample(_node); // Re-fetch assertion data.
176 _refresh_tick |= 1; // Set the "was refreshed" flag.
177 }
178
179 void DUIterator::verify_finish() {
180 // If the loop has killed the node, do not require it to re-run.
181 if (_node->_outcnt == 0) _refresh_tick &= ~1;
182 // If this assert triggers, it means that a loop used refresh_out_pos
183 // to re-synch an iteration index, but the loop did not correctly
184 // re-run itself, using a "while (progress)" construct.
185 // This iterator enforces the rule that you must keep trying the loop
186 // until it "runs clean" without any need for refreshing.
187 assert(!(_refresh_tick & 1), "the loop must run once with no refreshing");
188 }
189
190
191 void DUIterator_Fast::verify(const Node* node, bool at_end_ok) {
192 DUIterator_Common::verify(node, at_end_ok);
193 Node** out = node->_out;
194 uint cnt = node->_outcnt;
195 assert(cnt == _outcnt, "no insertions allowed");
196 assert(_outp >= out && _outp <= out + cnt - !at_end_ok, "outp in range");
197 // This last check is carefully designed to work for NO_OUT_ARRAY.
198 }
199
200 void DUIterator_Fast::verify_limit() {
201 const Node* node = _node;
202 verify(node, true);
203 assert(_outp == node->_out + node->_outcnt, "limit still correct");
204 }
205
206 void DUIterator_Fast::verify_resync() {
207 const Node* node = _node;
208 if (_outp == node->_out + _outcnt) {
209 // Note that the limit imax, not the pointer i, gets updated with the
210 // exact count of deletions. (For the pointer it's always "--i".)
211 assert(node->_outcnt+node->_del_tick == _outcnt+_del_tick, "no insertions allowed with deletion(s)");
212 // This is a limit pointer, with a name like "imax".
213 // Fudge the _last field so that the common assert will be happy.
214 _last = (Node*) node->_last_del;
215 DUIterator_Common::verify_resync();
216 } else {
217 assert(node->_outcnt < _outcnt, "no insertions allowed with deletion(s)");
218 // A normal internal pointer.
219 DUIterator_Common::verify_resync();
220 // Make sure we are still in sync, possibly with no more out-edges:
221 verify(node, true);
222 }
223 }
224
225 void DUIterator_Fast::verify_relimit(uint n) {
226 const Node* node = _node;
227 assert((int)n > 0, "use imax -= n only with a positive count");
228 // This must be a limit pointer, with a name like "imax".
229 assert(_outp == node->_out + node->_outcnt, "apply -= only to a limit (imax)");
230 // The reported number of deletions must match what the node saw.
231 assert(node->_del_tick == _del_tick + n, "must have deleted n edges");
232 // Fudge the _last field so that the common assert will be happy.
233 _last = (Node*) node->_last_del;
234 DUIterator_Common::verify_resync();
235 }
236
237 void DUIterator_Fast::reset(const DUIterator_Fast& that) {
238 assert(_outp == that._outp, "already assigned _outp");
239 DUIterator_Common::reset(that);
240 }
241
242 void DUIterator_Last::verify(const Node* node, bool at_end_ok) {
243 // at_end_ok means the _outp is allowed to underflow by 1
244 _outp += at_end_ok;
245 DUIterator_Fast::verify(node, at_end_ok); // check _del_tick, etc.
246 _outp -= at_end_ok;
247 assert(_outp == (node->_out + node->_outcnt) - 1, "pointer must point to end of nodes");
248 }
249
250 void DUIterator_Last::verify_limit() {
251 // Do not require the limit address to be resynched.
252 //verify(node, true);
253 assert(_outp == _node->_out, "limit still correct");
254 }
255
256 void DUIterator_Last::verify_step(uint num_edges) {
257 assert((int)num_edges > 0, "need non-zero edge count for loop progress");
258 _outcnt -= num_edges;
259 _del_tick += num_edges;
260 // Make sure we are still in sync, possibly with no more out-edges:
261 const Node* node = _node;
262 verify(node, true);
263 assert(node->_last_del == _last, "must have deleted the edge just produced");
264 }
265
266 #endif //OPTO_DU_ITERATOR_ASSERT
267
268
269 #endif //ASSERT
270
271
272 // This constant used to initialize _out may be any non-null value.
273 // The value NULL is reserved for the top node only.
274 #define NO_OUT_ARRAY ((Node**)-1)
275
276 // This funny expression handshakes with Node::operator new
277 // to pull Compile::current out of the new node's _out field,
278 // and then calls a subroutine which manages most field
279 // initializations. The only one which is tricky is the
280 // _idx field, which is const, and so must be initialized
281 // by a return value, not an assignment.
282 //
283 // (Aren't you thankful that Java finals don't require so many tricks?)
284 #define IDX_INIT(req) this->Init((req), (Compile*) this->_out)
285 #ifdef _MSC_VER // the IDX_INIT hack falls foul of warning C4355
286 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
287 #endif
288
289 // Out-of-line code from node constructors.
290 // Executed only when extra debug info. is being passed around.
291 static void init_node_notes(Compile* C, int idx, Node_Notes* nn) {
292 C->set_node_notes_at(idx, nn);
293 }
294
295 // Shared initialization code.
296 inline int Node::Init(int req, Compile* C) {
297 assert(Compile::current() == C, "must use operator new(Compile*)");
298 int idx = C->next_unique();
299
300 // Allocate memory for the necessary number of edges.
301 if (req > 0) {
302 // Allocate space for _in array to have double alignment.
303 _in = (Node **) ((char *) (C->node_arena()->Amalloc_D(req * sizeof(void*))));
304 #ifdef ASSERT
305 _in[req-1] = this; // magic cookie for assertion check
306 #endif
307 }
308 // If there are default notes floating around, capture them:
309 Node_Notes* nn = C->default_node_notes();
310 if (nn != NULL) init_node_notes(C, idx, nn);
311
312 // Note: At this point, C is dead,
313 // and we begin to initialize the new Node.
314
315 _cnt = _max = req;
316 _outcnt = _outmax = 0;
317 _class_id = Class_Node;
318 _flags = 0;
319 _out = NO_OUT_ARRAY;
320 return idx;
321 }
322
323 //------------------------------Node-------------------------------------------
324 // Create a Node, with a given number of required edges.
325 Node::Node(uint req)
326 : _idx(IDX_INIT(req))
327 {
328 assert( req < (uint)(MaxNodeLimit - NodeLimitFudgeFactor), "Input limit exceeded" );
329 debug_only( verify_construction() );
330 NOT_PRODUCT(nodes_created++);
331 if (req == 0) {
332 assert( _in == (Node**)this, "Must not pass arg count to 'new'" );
333 _in = NULL;
334 } else {
335 assert( _in[req-1] == this, "Must pass arg count to 'new'" );
336 Node** to = _in;
337 for(uint i = 0; i < req; i++) {
338 to[i] = NULL;
339 }
340 }
341 }
342
343 //------------------------------Node-------------------------------------------
344 Node::Node(Node *n0)
345 : _idx(IDX_INIT(1))
346 {
347 debug_only( verify_construction() );
348 NOT_PRODUCT(nodes_created++);
349 // Assert we allocated space for input array already
350 assert( _in[0] == this, "Must pass arg count to 'new'" );
351 assert( is_not_dead(n0), "can not use dead node");
352 _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
353 }
354
355 //------------------------------Node-------------------------------------------
356 Node::Node(Node *n0, Node *n1)
357 : _idx(IDX_INIT(2))
358 {
359 debug_only( verify_construction() );
360 NOT_PRODUCT(nodes_created++);
361 // Assert we allocated space for input array already
362 assert( _in[1] == this, "Must pass arg count to 'new'" );
363 assert( is_not_dead(n0), "can not use dead node");
364 assert( is_not_dead(n1), "can not use dead node");
365 _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
366 _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
367 }
368
369 //------------------------------Node-------------------------------------------
370 Node::Node(Node *n0, Node *n1, Node *n2)
371 : _idx(IDX_INIT(3))
372 {
373 debug_only( verify_construction() );
374 NOT_PRODUCT(nodes_created++);
375 // Assert we allocated space for input array already
376 assert( _in[2] == this, "Must pass arg count to 'new'" );
377 assert( is_not_dead(n0), "can not use dead node");
378 assert( is_not_dead(n1), "can not use dead node");
379 assert( is_not_dead(n2), "can not use dead node");
380 _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
381 _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
382 _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
383 }
384
385 //------------------------------Node-------------------------------------------
386 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3)
387 : _idx(IDX_INIT(4))
388 {
389 debug_only( verify_construction() );
390 NOT_PRODUCT(nodes_created++);
391 // Assert we allocated space for input array already
392 assert( _in[3] == this, "Must pass arg count to 'new'" );
393 assert( is_not_dead(n0), "can not use dead node");
394 assert( is_not_dead(n1), "can not use dead node");
395 assert( is_not_dead(n2), "can not use dead node");
396 assert( is_not_dead(n3), "can not use dead node");
397 _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
398 _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
399 _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
400 _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
401 }
402
403 //------------------------------Node-------------------------------------------
404 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3, Node *n4)
405 : _idx(IDX_INIT(5))
406 {
407 debug_only( verify_construction() );
408 NOT_PRODUCT(nodes_created++);
409 // Assert we allocated space for input array already
410 assert( _in[4] == this, "Must pass arg count to 'new'" );
411 assert( is_not_dead(n0), "can not use dead node");
412 assert( is_not_dead(n1), "can not use dead node");
413 assert( is_not_dead(n2), "can not use dead node");
414 assert( is_not_dead(n3), "can not use dead node");
415 assert( is_not_dead(n4), "can not use dead node");
416 _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
417 _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
418 _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
419 _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
420 _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
421 }
422
423 //------------------------------Node-------------------------------------------
424 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
425 Node *n4, Node *n5)
426 : _idx(IDX_INIT(6))
427 {
428 debug_only( verify_construction() );
429 NOT_PRODUCT(nodes_created++);
430 // Assert we allocated space for input array already
431 assert( _in[5] == this, "Must pass arg count to 'new'" );
432 assert( is_not_dead(n0), "can not use dead node");
433 assert( is_not_dead(n1), "can not use dead node");
434 assert( is_not_dead(n2), "can not use dead node");
435 assert( is_not_dead(n3), "can not use dead node");
436 assert( is_not_dead(n4), "can not use dead node");
437 assert( is_not_dead(n5), "can not use dead node");
438 _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
439 _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
440 _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
441 _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
442 _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
443 _in[5] = n5; if (n5 != NULL) n5->add_out((Node *)this);
444 }
445
446 //------------------------------Node-------------------------------------------
447 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
448 Node *n4, Node *n5, Node *n6)
449 : _idx(IDX_INIT(7))
450 {
451 debug_only( verify_construction() );
452 NOT_PRODUCT(nodes_created++);
453 // Assert we allocated space for input array already
454 assert( _in[6] == this, "Must pass arg count to 'new'" );
455 assert( is_not_dead(n0), "can not use dead node");
456 assert( is_not_dead(n1), "can not use dead node");
457 assert( is_not_dead(n2), "can not use dead node");
458 assert( is_not_dead(n3), "can not use dead node");
459 assert( is_not_dead(n4), "can not use dead node");
460 assert( is_not_dead(n5), "can not use dead node");
461 assert( is_not_dead(n6), "can not use dead node");
462 _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
463 _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
464 _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
465 _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
466 _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
467 _in[5] = n5; if (n5 != NULL) n5->add_out((Node *)this);
468 _in[6] = n6; if (n6 != NULL) n6->add_out((Node *)this);
469 }
470
471
472 //------------------------------clone------------------------------------------
473 // Clone a Node.
474 Node *Node::clone() const {
475 Compile *compile = Compile::current();
476 uint s = size_of(); // Size of inherited Node
477 Node *n = (Node*)compile->node_arena()->Amalloc_D(size_of() + _max*sizeof(Node*));
478 Copy::conjoint_words_to_lower((HeapWord*)this, (HeapWord*)n, s);
479 // Set the new input pointer array
480 n->_in = (Node**)(((char*)n)+s);
481 // Cannot share the old output pointer array, so kill it
482 n->_out = NO_OUT_ARRAY;
483 // And reset the counters to 0
484 n->_outcnt = 0;
485 n->_outmax = 0;
486 // Unlock this guy, since he is not in any hash table.
487 debug_only(n->_hash_lock = 0);
488 // Walk the old node's input list to duplicate its edges
489 uint i;
490 for( i = 0; i < len(); i++ ) {
491 Node *x = in(i);
492 n->_in[i] = x;
493 if (x != NULL) x->add_out(n);
494 }
495 if (is_macro())
496 compile->add_macro_node(n);
497 if (is_expensive())
498 compile->add_expensive_node(n);
499
500 n->set_idx(compile->next_unique()); // Get new unique index as well
501 debug_only( n->verify_construction() );
502 NOT_PRODUCT(nodes_created++);
503 // Do not patch over the debug_idx of a clone, because it makes it
504 // impossible to break on the clone's moment of creation.
505 //debug_only( n->set_debug_idx( debug_idx() ) );
506
507 compile->copy_node_notes_to(n, (Node*) this);
508
509 // MachNode clone
510 uint nopnds;
511 if (this->is_Mach() && (nopnds = this->as_Mach()->num_opnds()) > 0) {
512 MachNode *mach = n->as_Mach();
513 MachNode *mthis = this->as_Mach();
514 // Get address of _opnd_array.
515 // It should be the same offset since it is the clone of this node.
516 MachOper **from = mthis->_opnds;
517 MachOper **to = (MachOper **)((size_t)(&mach->_opnds) +
518 pointer_delta((const void*)from,
519 (const void*)(&mthis->_opnds), 1));
520 mach->_opnds = to;
521 for ( uint i = 0; i < nopnds; ++i ) {
522 to[i] = from[i]->clone(compile);
523 }
524 }
525 // cloning CallNode may need to clone JVMState
526 if (n->is_Call()) {
527 CallNode *call = n->as_Call();
528 call->clone_jvms();
529 }
530 if (n->is_SafePoint()) {
531 n->as_SafePoint()->clone_replaced_nodes();
532 }
533 return n; // Return the clone
534 }
535
536 //---------------------------setup_is_top--------------------------------------
537 // Call this when changing the top node, to reassert the invariants
538 // required by Node::is_top. See Compile::set_cached_top_node.
539 void Node::setup_is_top() {
540 if (this == (Node*)Compile::current()->top()) {
541 // This node has just become top. Kill its out array.
542 _outcnt = _outmax = 0;
543 _out = NULL; // marker value for top
544 assert(is_top(), "must be top");
545 } else {
546 if (_out == NULL) _out = NO_OUT_ARRAY;
547 assert(!is_top(), "must not be top");
548 }
549 }
550
551
552 //------------------------------~Node------------------------------------------
553 // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
554 extern int reclaim_idx ;
555 extern int reclaim_in ;
556 extern int reclaim_node;
557 void Node::destruct() {
558 // Eagerly reclaim unique Node numberings
559 Compile* compile = Compile::current();
560 if ((uint)_idx+1 == compile->unique()) {
561 compile->set_unique(compile->unique()-1);
562 #ifdef ASSERT
563 reclaim_idx++;
564 #endif
565 }
566 // Clear debug info:
567 Node_Notes* nn = compile->node_notes_at(_idx);
568 if (nn != NULL) nn->clear();
569 // Walk the input array, freeing the corresponding output edges
570 _cnt = _max; // forget req/prec distinction
571 uint i;
572 for( i = 0; i < _max; i++ ) {
573 set_req(i, NULL);
574 //assert(def->out(def->outcnt()-1) == (Node *)this,"bad def-use hacking in reclaim");
575 }
576 assert(outcnt() == 0, "deleting a node must not leave a dangling use");
577 // See if the input array was allocated just prior to the object
578 int edge_size = _max*sizeof(void*);
579 int out_edge_size = _outmax*sizeof(void*);
580 char *edge_end = ((char*)_in) + edge_size;
581 char *out_array = (char*)(_out == NO_OUT_ARRAY? NULL: _out);
582 char *out_edge_end = out_array + out_edge_size;
583 int node_size = size_of();
584
585 // Free the output edge array
586 if (out_edge_size > 0) {
587 #ifdef ASSERT
588 if( out_edge_end == compile->node_arena()->hwm() )
589 reclaim_in += out_edge_size; // count reclaimed out edges with in edges
590 #endif
591 compile->node_arena()->Afree(out_array, out_edge_size);
592 }
593
594 // Free the input edge array and the node itself
595 if( edge_end == (char*)this ) {
596 #ifdef ASSERT
597 if( edge_end+node_size == compile->node_arena()->hwm() ) {
598 reclaim_in += edge_size;
599 reclaim_node+= node_size;
600 }
601 #else
602 // It was; free the input array and object all in one hit
603 compile->node_arena()->Afree(_in,edge_size+node_size);
604 #endif
605 } else {
606
607 // Free just the input array
608 #ifdef ASSERT
609 if( edge_end == compile->node_arena()->hwm() )
610 reclaim_in += edge_size;
611 #endif
612 compile->node_arena()->Afree(_in,edge_size);
613
614 // Free just the object
615 #ifdef ASSERT
616 if( ((char*)this) + node_size == compile->node_arena()->hwm() )
617 reclaim_node+= node_size;
618 #else
619 compile->node_arena()->Afree(this,node_size);
620 #endif
621 }
622 if (is_macro()) {
623 compile->remove_macro_node(this);
624 }
625 if (is_expensive()) {
626 compile->remove_expensive_node(this);
627 }
628 if (is_SafePoint()) {
629 as_SafePoint()->delete_replaced_nodes();
630 }
631 #ifdef ASSERT
632 // We will not actually delete the storage, but we'll make the node unusable.
633 *(address*)this = badAddress; // smash the C++ vtbl, probably
634 _in = _out = (Node**) badAddress;
635 _max = _cnt = _outmax = _outcnt = 0;
636 #endif
637 }
638
639 //------------------------------grow-------------------------------------------
640 // Grow the input array, making space for more edges
641 void Node::grow( uint len ) {
642 Arena* arena = Compile::current()->node_arena();
643 uint new_max = _max;
644 if( new_max == 0 ) {
645 _max = 4;
646 _in = (Node**)arena->Amalloc(4*sizeof(Node*));
647 Node** to = _in;
648 to[0] = NULL;
649 to[1] = NULL;
650 to[2] = NULL;
651 to[3] = NULL;
652 return;
653 }
654 while( new_max <= len ) new_max <<= 1; // Find next power-of-2
655 // Trimming to limit allows a uint8 to handle up to 255 edges.
656 // Previously I was using only powers-of-2 which peaked at 128 edges.
657 //if( new_max >= limit ) new_max = limit-1;
658 _in = (Node**)arena->Arealloc(_in, _max*sizeof(Node*), new_max*sizeof(Node*));
659 Copy::zero_to_bytes(&_in[_max], (new_max-_max)*sizeof(Node*)); // NULL all new space
660 _max = new_max; // Record new max length
661 // This assertion makes sure that Node::_max is wide enough to
662 // represent the numerical value of new_max.
663 assert(_max == new_max && _max > len, "int width of _max is too small");
664 }
665
666 //-----------------------------out_grow----------------------------------------
667 // Grow the input array, making space for more edges
668 void Node::out_grow( uint len ) {
669 assert(!is_top(), "cannot grow a top node's out array");
670 Arena* arena = Compile::current()->node_arena();
671 uint new_max = _outmax;
672 if( new_max == 0 ) {
673 _outmax = 4;
674 _out = (Node **)arena->Amalloc(4*sizeof(Node*));
675 return;
676 }
677 while( new_max <= len ) new_max <<= 1; // Find next power-of-2
678 // Trimming to limit allows a uint8 to handle up to 255 edges.
679 // Previously I was using only powers-of-2 which peaked at 128 edges.
680 //if( new_max >= limit ) new_max = limit-1;
681 assert(_out != NULL && _out != NO_OUT_ARRAY, "out must have sensible value");
682 _out = (Node**)arena->Arealloc(_out,_outmax*sizeof(Node*),new_max*sizeof(Node*));
683 //Copy::zero_to_bytes(&_out[_outmax], (new_max-_outmax)*sizeof(Node*)); // NULL all new space
684 _outmax = new_max; // Record new max length
685 // This assertion makes sure that Node::_max is wide enough to
686 // represent the numerical value of new_max.
687 assert(_outmax == new_max && _outmax > len, "int width of _outmax is too small");
688 }
689
690 #ifdef ASSERT
691 //------------------------------is_dead----------------------------------------
692 bool Node::is_dead() const {
693 // Mach and pinch point nodes may look like dead.
694 if( is_top() || is_Mach() || (Opcode() == Op_Node && _outcnt > 0) )
695 return false;
696 for( uint i = 0; i < _max; i++ )
697 if( _in[i] != NULL )
698 return false;
699 dump();
700 return true;
701 }
702 #endif
703
704
705 //------------------------------is_unreachable---------------------------------
706 bool Node::is_unreachable(PhaseIterGVN &igvn) const {
707 assert(!is_Mach(), "doesn't work with MachNodes");
708 return outcnt() == 0 || igvn.type(this) == Type::TOP || in(0)->is_top();
709 }
710
711 //------------------------------add_req----------------------------------------
712 // Add a new required input at the end
713 void Node::add_req( Node *n ) {
714 assert( is_not_dead(n), "can not use dead node");
715
716 // Look to see if I can move precedence down one without reallocating
717 if( (_cnt >= _max) || (in(_max-1) != NULL) )
718 grow( _max+1 );
719
720 // Find a precedence edge to move
721 if( in(_cnt) != NULL ) { // Next precedence edge is busy?
722 uint i;
723 for( i=_cnt; i<_max; i++ )
724 if( in(i) == NULL ) // Find the NULL at end of prec edge list
725 break; // There must be one, since we grew the array
726 _in[i] = in(_cnt); // Move prec over, making space for req edge
727 }
728 _in[_cnt++] = n; // Stuff over old prec edge
729 if (n != NULL) n->add_out((Node *)this);
730 }
731
732 //---------------------------add_req_batch-------------------------------------
733 // Add a new required input at the end
734 void Node::add_req_batch( Node *n, uint m ) {
735 assert( is_not_dead(n), "can not use dead node");
736 // check various edge cases
737 if ((int)m <= 1) {
738 assert((int)m >= 0, "oob");
739 if (m != 0) add_req(n);
740 return;
741 }
742
743 // Look to see if I can move precedence down one without reallocating
744 if( (_cnt+m) > _max || _in[_max-m] )
745 grow( _max+m );
746
747 // Find a precedence edge to move
748 if( _in[_cnt] != NULL ) { // Next precedence edge is busy?
749 uint i;
750 for( i=_cnt; i<_max; i++ )
751 if( _in[i] == NULL ) // Find the NULL at end of prec edge list
752 break; // There must be one, since we grew the array
753 // Slide all the precs over by m positions (assume #prec << m).
754 Copy::conjoint_words_to_higher((HeapWord*)&_in[_cnt], (HeapWord*)&_in[_cnt+m], ((i-_cnt)*sizeof(Node*)));
755 }
756
757 // Stuff over the old prec edges
758 for(uint i=0; i<m; i++ ) {
759 _in[_cnt++] = n;
760 }
761
762 // Insert multiple out edges on the node.
763 if (n != NULL && !n->is_top()) {
764 for(uint i=0; i<m; i++ ) {
765 n->add_out((Node *)this);
766 }
767 }
768 }
769
770 //------------------------------del_req----------------------------------------
771 // Delete the required edge and compact the edge array
772 void Node::del_req( uint idx ) {
773 assert( idx < _cnt, "oob");
774 assert( !VerifyHashTableKeys || _hash_lock == 0,
775 "remove node from hash table before modifying it");
776 // First remove corresponding def-use edge
777 Node *n = in(idx);
778 if (n != NULL) n->del_out((Node *)this);
779 _in[idx] = in(--_cnt); // Compact the array
780 _in[_cnt] = NULL; // NULL out emptied slot
781 }
782
783 //------------------------------ins_req----------------------------------------
784 // Insert a new required input at the end
785 void Node::ins_req( uint idx, Node *n ) {
786 assert( is_not_dead(n), "can not use dead node");
787 add_req(NULL); // Make space
788 assert( idx < _max, "Must have allocated enough space");
789 // Slide over
790 if(_cnt-idx-1 > 0) {
791 Copy::conjoint_words_to_higher((HeapWord*)&_in[idx], (HeapWord*)&_in[idx+1], ((_cnt-idx-1)*sizeof(Node*)));
792 }
793 _in[idx] = n; // Stuff over old required edge
794 if (n != NULL) n->add_out((Node *)this); // Add reciprocal def-use edge
795 }
796
797 //-----------------------------find_edge---------------------------------------
798 int Node::find_edge(Node* n) {
799 for (uint i = 0; i < len(); i++) {
800 if (_in[i] == n) return i;
801 }
802 return -1;
803 }
804
805 //----------------------------replace_edge-------------------------------------
806 int Node::replace_edge(Node* old, Node* neww) {
807 if (old == neww) return 0; // nothing to do
808 uint nrep = 0;
809 for (uint i = 0; i < len(); i++) {
810 if (in(i) == old) {
811 if (i < req())
812 set_req(i, neww);
813 else
814 set_prec(i, neww);
815 nrep++;
816 }
817 }
818 return nrep;
819 }
820
821 //-------------------------disconnect_inputs-----------------------------------
822 // NULL out all inputs to eliminate incoming Def-Use edges.
823 // Return the number of edges between 'n' and 'this'
824 int Node::disconnect_inputs(Node *n, Compile* C) {
825 int edges_to_n = 0;
826
827 uint cnt = req();
828 for( uint i = 0; i < cnt; ++i ) {
829 if( in(i) == 0 ) continue;
830 if( in(i) == n ) ++edges_to_n;
831 set_req(i, NULL);
832 }
833 // Remove precedence edges if any exist
834 // Note: Safepoints may have precedence edges, even during parsing
835 if( (req() != len()) && (in(req()) != NULL) ) {
836 uint max = len();
837 for( uint i = 0; i < max; ++i ) {
838 if( in(i) == 0 ) continue;
839 if( in(i) == n ) ++edges_to_n;
840 set_prec(i, NULL);
841 }
842 }
843
844 // Node::destruct requires all out edges be deleted first
845 // debug_only(destruct();) // no reuse benefit expected
846 if (edges_to_n == 0) {
847 C->record_dead_node(_idx);
848 }
849 return edges_to_n;
850 }
851
852 //-----------------------------uncast---------------------------------------
853 // %%% Temporary, until we sort out CheckCastPP vs. CastPP.
854 // Strip away casting. (It is depth-limited.)
855 Node* Node::uncast() const {
856 // Should be inline:
857 //return is_ConstraintCast() ? uncast_helper(this) : (Node*) this;
858 if (is_ConstraintCast() || is_CheckCastPP())
859 return uncast_helper(this);
860 else
861 return (Node*) this;
862 }
863
864 //---------------------------uncast_helper-------------------------------------
865 Node* Node::uncast_helper(const Node* p) {
866 #ifdef ASSERT
867 uint depth_count = 0;
868 const Node* orig_p = p;
869 #endif
870
871 while (true) {
872 #ifdef ASSERT
873 if (depth_count >= K) {
874 orig_p->dump(4);
875 if (p != orig_p)
876 p->dump(1);
877 }
878 assert(depth_count++ < K, "infinite loop in Node::uncast_helper");
879 #endif
880 if (p == NULL || p->req() != 2) {
881 break;
882 } else if (p->is_ConstraintCast()) {
883 p = p->in(1);
884 } else if (p->is_CheckCastPP()) {
885 p = p->in(1);
886 } else {
887 break;
888 }
889 }
890 return (Node*) p;
891 }
892
893 //------------------------------add_prec---------------------------------------
894 // Add a new precedence input. Precedence inputs are unordered, with
895 // duplicates removed and NULLs packed down at the end.
896 void Node::add_prec( Node *n ) {
897 assert( is_not_dead(n), "can not use dead node");
898
899 // Check for NULL at end
900 if( _cnt >= _max || in(_max-1) )
901 grow( _max+1 );
902
903 // Find a precedence edge to move
904 uint i = _cnt;
905 while( in(i) != NULL ) i++;
906 _in[i] = n; // Stuff prec edge over NULL
907 if ( n != NULL) n->add_out((Node *)this); // Add mirror edge
908 }
909
910 //------------------------------rm_prec----------------------------------------
911 // Remove a precedence input. Precedence inputs are unordered, with
912 // duplicates removed and NULLs packed down at the end.
913 void Node::rm_prec( uint j ) {
914
915 // Find end of precedence list to pack NULLs
916 uint i;
917 for( i=j; i<_max; i++ )
918 if( !_in[i] ) // Find the NULL at end of prec edge list
919 break;
920 if (_in[j] != NULL) _in[j]->del_out((Node *)this);
921 _in[j] = _in[--i]; // Move last element over removed guy
922 _in[i] = NULL; // NULL out last element
923 }
924
925 //------------------------------size_of----------------------------------------
926 uint Node::size_of() const { return sizeof(*this); }
927
928 //------------------------------ideal_reg--------------------------------------
929 uint Node::ideal_reg() const { return 0; }
930
931 //------------------------------jvms-------------------------------------------
932 JVMState* Node::jvms() const { return NULL; }
933
934 #ifdef ASSERT
935 //------------------------------jvms-------------------------------------------
936 bool Node::verify_jvms(const JVMState* using_jvms) const {
937 for (JVMState* jvms = this->jvms(); jvms != NULL; jvms = jvms->caller()) {
938 if (jvms == using_jvms) return true;
939 }
940 return false;
941 }
942
943 //------------------------------init_NodeProperty------------------------------
944 void Node::init_NodeProperty() {
945 assert(_max_classes <= max_jushort, "too many NodeProperty classes");
946 assert(_max_flags <= max_jushort, "too many NodeProperty flags");
947 }
948 #endif
949
950 //------------------------------format-----------------------------------------
951 // Print as assembly
952 void Node::format( PhaseRegAlloc *, outputStream *st ) const {}
953 //------------------------------emit-------------------------------------------
954 // Emit bytes starting at parameter 'ptr'.
955 void Node::emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const {}
956 //------------------------------lateExpand-------------------------------------
957 // Expand node after register allocation.
958 void Node::lateExpand(GrowableArray <Node *> *nodes, PhaseRegAlloc *ra_) {}
959 //------------------------------size-------------------------------------------
960 // Size of instruction in bytes
961 uint Node::size(PhaseRegAlloc *ra_) const { return 0; }
962
963 //------------------------------CFG Construction-------------------------------
964 // Nodes that end basic blocks, e.g. IfTrue/IfFalse, JumpProjNode, Root,
965 // Goto and Return.
966 const Node *Node::is_block_proj() const { return 0; }
967
968 // Minimum guaranteed type
969 const Type *Node::bottom_type() const { return Type::BOTTOM; }
970
971
972 //------------------------------raise_bottom_type------------------------------
973 // Get the worst-case Type output for this Node.
974 void Node::raise_bottom_type(const Type* new_type) {
975 if (is_Type()) {
976 TypeNode *n = this->as_Type();
977 if (VerifyAliases) {
978 assert(new_type->higher_equal(n->type()), "new type must refine old type");
979 }
980 n->set_type(new_type);
981 } else if (is_Load()) {
982 LoadNode *n = this->as_Load();
983 if (VerifyAliases) {
984 assert(new_type->higher_equal(n->type()), "new type must refine old type");
985 }
986 n->set_type(new_type);
987 }
988 }
989
990 //------------------------------Identity---------------------------------------
991 // Return a node that the given node is equivalent to.
992 Node *Node::Identity( PhaseTransform * ) {
993 return this; // Default to no identities
994 }
995
996 //------------------------------Value------------------------------------------
997 // Compute a new Type for a node using the Type of the inputs.
998 const Type *Node::Value( PhaseTransform * ) const {
999 return bottom_type(); // Default to worst-case Type
1000 }
1001
1002 //------------------------------Ideal------------------------------------------
1003 //
1004 // 'Idealize' the graph rooted at this Node.
1005 //
1006 // In order to be efficient and flexible there are some subtle invariants
1007 // these Ideal calls need to hold. Running with '+VerifyIterativeGVN' checks
1008 // these invariants, although its too slow to have on by default. If you are
1009 // hacking an Ideal call, be sure to test with +VerifyIterativeGVN!
1010 //
1011 // The Ideal call almost arbitrarily reshape the graph rooted at the 'this'
1012 // pointer. If ANY change is made, it must return the root of the reshaped
1013 // graph - even if the root is the same Node. Example: swapping the inputs
1014 // to an AddINode gives the same answer and same root, but you still have to
1015 // return the 'this' pointer instead of NULL.
1016 //
1017 // You cannot return an OLD Node, except for the 'this' pointer. Use the
1018 // Identity call to return an old Node; basically if Identity can find
1019 // another Node have the Ideal call make no change and return NULL.
1020 // Example: AddINode::Ideal must check for add of zero; in this case it
1021 // returns NULL instead of doing any graph reshaping.
1022 //
1023 // You cannot modify any old Nodes except for the 'this' pointer. Due to
1024 // sharing there may be other users of the old Nodes relying on their current
1025 // semantics. Modifying them will break the other users.
1026 // Example: when reshape "(X+3)+4" into "X+7" you must leave the Node for
1027 // "X+3" unchanged in case it is shared.
1028 //
1029 // If you modify the 'this' pointer's inputs, you should use
1030 // 'set_req'. If you are making a new Node (either as the new root or
1031 // some new internal piece) you may use 'init_req' to set the initial
1032 // value. You can make a new Node with either 'new' or 'clone'. In
1033 // either case, def-use info is correctly maintained.
1034 //
1035 // Example: reshape "(X+3)+4" into "X+7":
1036 // set_req(1, in(1)->in(1));
1037 // set_req(2, phase->intcon(7));
1038 // return this;
1039 // Example: reshape "X*4" into "X<<2"
1040 // return new (C) LShiftINode(in(1), phase->intcon(2));
1041 //
1042 // You must call 'phase->transform(X)' on any new Nodes X you make, except
1043 // for the returned root node. Example: reshape "X*31" with "(X<<5)-X".
1044 // Node *shift=phase->transform(new(C)LShiftINode(in(1),phase->intcon(5)));
1045 // return new (C) AddINode(shift, in(1));
1046 //
1047 // When making a Node for a constant use 'phase->makecon' or 'phase->intcon'.
1048 // These forms are faster than 'phase->transform(new (C) ConNode())' and Do
1049 // The Right Thing with def-use info.
1050 //
1051 // You cannot bury the 'this' Node inside of a graph reshape. If the reshaped
1052 // graph uses the 'this' Node it must be the root. If you want a Node with
1053 // the same Opcode as the 'this' pointer use 'clone'.
1054 //
1055 Node *Node::Ideal(PhaseGVN *phase, bool can_reshape) {
1056 return NULL; // Default to being Ideal already
1057 }
1058
1059 // Some nodes have specific Ideal subgraph transformations only if they are
1060 // unique users of specific nodes. Such nodes should be put on IGVN worklist
1061 // for the transformations to happen.
1062 bool Node::has_special_unique_user() const {
1063 assert(outcnt() == 1, "match only for unique out");
1064 Node* n = unique_out();
1065 int op = Opcode();
1066 if( this->is_Store() ) {
1067 // Condition for back-to-back stores folding.
1068 return n->Opcode() == op && n->in(MemNode::Memory) == this;
1069 } else if( op == Op_AddL ) {
1070 // Condition for convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
1071 return n->Opcode() == Op_ConvL2I && n->in(1) == this;
1072 } else if( op == Op_SubI || op == Op_SubL ) {
1073 // Condition for subI(x,subI(y,z)) ==> subI(addI(x,z),y)
1074 return n->Opcode() == op && n->in(2) == this;
1075 }
1076 return false;
1077 };
1078
1079 //--------------------------find_exact_control---------------------------------
1080 // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1081 Node* Node::find_exact_control(Node* ctrl) {
1082 if (ctrl == NULL && this->is_Region())
1083 ctrl = this->as_Region()->is_copy();
1084
1085 if (ctrl != NULL && ctrl->is_CatchProj()) {
1086 if (ctrl->as_CatchProj()->_con == CatchProjNode::fall_through_index)
1087 ctrl = ctrl->in(0);
1088 if (ctrl != NULL && !ctrl->is_top())
1089 ctrl = ctrl->in(0);
1090 }
1091
1092 if (ctrl != NULL && ctrl->is_Proj())
1093 ctrl = ctrl->in(0);
1094
1095 return ctrl;
1096 }
1097
1098 //--------------------------dominates------------------------------------------
1099 // Helper function for MemNode::all_controls_dominate().
1100 // Check if 'this' control node dominates or equal to 'sub' control node.
1101 // We already know that if any path back to Root or Start reaches 'this',
1102 // then all paths so, so this is a simple search for one example,
1103 // not an exhaustive search for a counterexample.
1104 bool Node::dominates(Node* sub, Node_List &nlist) {
1105 assert(this->is_CFG(), "expecting control");
1106 assert(sub != NULL && sub->is_CFG(), "expecting control");
1107
1108 // detect dead cycle without regions
1109 int iterations_without_region_limit = DominatorSearchLimit;
1110
1111 Node* orig_sub = sub;
1112 Node* dom = this;
1113 bool met_dom = false;
1114 nlist.clear();
1115
1116 // Walk 'sub' backward up the chain to 'dom', watching for regions.
1117 // After seeing 'dom', continue up to Root or Start.
1118 // If we hit a region (backward split point), it may be a loop head.
1119 // Keep going through one of the region's inputs. If we reach the
1120 // same region again, go through a different input. Eventually we
1121 // will either exit through the loop head, or give up.
1122 // (If we get confused, break out and return a conservative 'false'.)
1123 while (sub != NULL) {
1124 if (sub->is_top()) break; // Conservative answer for dead code.
1125 if (sub == dom) {
1126 if (nlist.size() == 0) {
1127 // No Region nodes except loops were visited before and the EntryControl
1128 // path was taken for loops: it did not walk in a cycle.
1129 return true;
1130 } else if (met_dom) {
1131 break; // already met before: walk in a cycle
1132 } else {
1133 // Region nodes were visited. Continue walk up to Start or Root
1134 // to make sure that it did not walk in a cycle.
1135 met_dom = true; // first time meet
1136 iterations_without_region_limit = DominatorSearchLimit; // Reset
1137 }
1138 }
1139 if (sub->is_Start() || sub->is_Root()) {
1140 // Success if we met 'dom' along a path to Start or Root.
1141 // We assume there are no alternative paths that avoid 'dom'.
1142 // (This assumption is up to the caller to ensure!)
1143 return met_dom;
1144 }
1145 Node* up = sub->in(0);
1146 // Normalize simple pass-through regions and projections:
1147 up = sub->find_exact_control(up);
1148 // If sub == up, we found a self-loop. Try to push past it.
1149 if (sub == up && sub->is_Loop()) {
1150 // Take loop entry path on the way up to 'dom'.
1151 up = sub->in(1); // in(LoopNode::EntryControl);
1152 } else if (sub == up && sub->is_Region() && sub->req() != 3) {
1153 // Always take in(1) path on the way up to 'dom' for clone regions
1154 // (with only one input) or regions which merge > 2 paths
1155 // (usually used to merge fast/slow paths).
1156 up = sub->in(1);
1157 } else if (sub == up && sub->is_Region()) {
1158 // Try both paths for Regions with 2 input paths (it may be a loop head).
1159 // It could give conservative 'false' answer without information
1160 // which region's input is the entry path.
1161 iterations_without_region_limit = DominatorSearchLimit; // Reset
1162
1163 bool region_was_visited_before = false;
1164 // Was this Region node visited before?
1165 // If so, we have reached it because we accidentally took a
1166 // loop-back edge from 'sub' back into the body of the loop,
1167 // and worked our way up again to the loop header 'sub'.
1168 // So, take the first unexplored path on the way up to 'dom'.
1169 for (int j = nlist.size() - 1; j >= 0; j--) {
1170 intptr_t ni = (intptr_t)nlist.at(j);
1171 Node* visited = (Node*)(ni & ~1);
1172 bool visited_twice_already = ((ni & 1) != 0);
1173 if (visited == sub) {
1174 if (visited_twice_already) {
1175 // Visited 2 paths, but still stuck in loop body. Give up.
1176 return false;
1177 }
1178 // The Region node was visited before only once.
1179 // (We will repush with the low bit set, below.)
1180 nlist.remove(j);
1181 // We will find a new edge and re-insert.
1182 region_was_visited_before = true;
1183 break;
1184 }
1185 }
1186
1187 // Find an incoming edge which has not been seen yet; walk through it.
1188 assert(up == sub, "");
1189 uint skip = region_was_visited_before ? 1 : 0;
1190 for (uint i = 1; i < sub->req(); i++) {
1191 Node* in = sub->in(i);
1192 if (in != NULL && !in->is_top() && in != sub) {
1193 if (skip == 0) {
1194 up = in;
1195 break;
1196 }
1197 --skip; // skip this nontrivial input
1198 }
1199 }
1200
1201 // Set 0 bit to indicate that both paths were taken.
1202 nlist.push((Node*)((intptr_t)sub + (region_was_visited_before ? 1 : 0)));
1203 }
1204
1205 if (up == sub) {
1206 break; // some kind of tight cycle
1207 }
1208 if (up == orig_sub && met_dom) {
1209 // returned back after visiting 'dom'
1210 break; // some kind of cycle
1211 }
1212 if (--iterations_without_region_limit < 0) {
1213 break; // dead cycle
1214 }
1215 sub = up;
1216 }
1217
1218 // Did not meet Root or Start node in pred. chain.
1219 // Conservative answer for dead code.
1220 return false;
1221 }
1222
1223 //------------------------------remove_dead_region-----------------------------
1224 // This control node is dead. Follow the subgraph below it making everything
1225 // using it dead as well. This will happen normally via the usual IterGVN
1226 // worklist but this call is more efficient. Do not update use-def info
1227 // inside the dead region, just at the borders.
1228 static void kill_dead_code( Node *dead, PhaseIterGVN *igvn ) {
1229 // Con's are a popular node to re-hit in the hash table again.
1230 if( dead->is_Con() ) return;
1231
1232 // Can't put ResourceMark here since igvn->_worklist uses the same arena
1233 // for verify pass with +VerifyOpto and we add/remove elements in it here.
1234 Node_List nstack(Thread::current()->resource_area());
1235
1236 Node *top = igvn->C->top();
1237 nstack.push(dead);
1238 bool has_irreducible_loop = igvn->C->has_irreducible_loop();
1239
1240 while (nstack.size() > 0) {
1241 dead = nstack.pop();
1242 if (dead->outcnt() > 0) {
1243 // Keep dead node on stack until all uses are processed.
1244 nstack.push(dead);
1245 // For all Users of the Dead... ;-)
1246 for (DUIterator_Last kmin, k = dead->last_outs(kmin); k >= kmin; ) {
1247 Node* use = dead->last_out(k);
1248 igvn->hash_delete(use); // Yank from hash table prior to mod
1249 if (use->in(0) == dead) { // Found another dead node
1250 assert (!use->is_Con(), "Control for Con node should be Root node.");
1251 use->set_req(0, top); // Cut dead edge to prevent processing
1252 nstack.push(use); // the dead node again.
1253 } else if (!has_irreducible_loop && // Backedge could be alive in irreducible loop
1254 use->is_Loop() && !use->is_Root() && // Don't kill Root (RootNode extends LoopNode)
1255 use->in(LoopNode::EntryControl) == dead) { // Dead loop if its entry is dead
1256 use->set_req(LoopNode::EntryControl, top); // Cut dead edge to prevent processing
1257 use->set_req(0, top); // Cut self edge
1258 nstack.push(use);
1259 } else { // Else found a not-dead user
1260 // Dead if all inputs are top or null
1261 bool dead_use = !use->is_Root(); // Keep empty graph alive
1262 for (uint j = 1; j < use->req(); j++) {
1263 Node* in = use->in(j);
1264 if (in == dead) { // Turn all dead inputs into TOP
1265 use->set_req(j, top);
1266 } else if (in != NULL && !in->is_top()) {
1267 dead_use = false;
1268 }
1269 }
1270 if (dead_use) {
1271 if (use->is_Region()) {
1272 use->set_req(0, top); // Cut self edge
1273 }
1274 nstack.push(use);
1275 } else {
1276 igvn->_worklist.push(use);
1277 }
1278 }
1279 // Refresh the iterator, since any number of kills might have happened.
1280 k = dead->last_outs(kmin);
1281 }
1282 } else { // (dead->outcnt() == 0)
1283 // Done with outputs.
1284 igvn->hash_delete(dead);
1285 igvn->_worklist.remove(dead);
1286 igvn->set_type(dead, Type::TOP);
1287 if (dead->is_macro()) {
1288 igvn->C->remove_macro_node(dead);
1289 }
1290 if (dead->is_expensive()) {
1291 igvn->C->remove_expensive_node(dead);
1292 }
1293 igvn->C->record_dead_node(dead->_idx);
1294 // Kill all inputs to the dead guy
1295 for (uint i=0; i < dead->req(); i++) {
1296 Node *n = dead->in(i); // Get input to dead guy
1297 if (n != NULL && !n->is_top()) { // Input is valid?
1298 dead->set_req(i, top); // Smash input away
1299 if (n->outcnt() == 0) { // Input also goes dead?
1300 if (!n->is_Con())
1301 nstack.push(n); // Clear it out as well
1302 } else if (n->outcnt() == 1 &&
1303 n->has_special_unique_user()) {
1304 igvn->add_users_to_worklist( n );
1305 } else if (n->outcnt() <= 2 && n->is_Store()) {
1306 // Push store's uses on worklist to enable folding optimization for
1307 // store/store and store/load to the same address.
1308 // The restriction (outcnt() <= 2) is the same as in set_req_X()
1309 // and remove_globally_dead_node().
1310 igvn->add_users_to_worklist( n );
1311 }
1312 }
1313 }
1314 } // (dead->outcnt() == 0)
1315 } // while (nstack.size() > 0) for outputs
1316 return;
1317 }
1318
1319 //------------------------------remove_dead_region-----------------------------
1320 bool Node::remove_dead_region(PhaseGVN *phase, bool can_reshape) {
1321 Node *n = in(0);
1322 if( !n ) return false;
1323 // Lost control into this guy? I.e., it became unreachable?
1324 // Aggressively kill all unreachable code.
1325 if (can_reshape && n->is_top()) {
1326 kill_dead_code(this, phase->is_IterGVN());
1327 return false; // Node is dead.
1328 }
1329
1330 if( n->is_Region() && n->as_Region()->is_copy() ) {
1331 Node *m = n->nonnull_req();
1332 set_req(0, m);
1333 return true;
1334 }
1335 return false;
1336 }
1337
1338 //------------------------------Ideal_DU_postCCP-------------------------------
1339 // Idealize graph, using DU info. Must clone result into new-space
1340 Node *Node::Ideal_DU_postCCP( PhaseCCP * ) {
1341 return NULL; // Default to no change
1342 }
1343
1344 //------------------------------hash-------------------------------------------
1345 // Hash function over Nodes.
1346 uint Node::hash() const {
1347 uint sum = 0;
1348 for( uint i=0; i<_cnt; i++ ) // Add in all inputs
1349 sum = (sum<<1)-(uintptr_t)in(i); // Ignore embedded NULLs
1350 return (sum>>2) + _cnt + Opcode();
1351 }
1352
1353 //------------------------------cmp--------------------------------------------
1354 // Compare special parts of simple Nodes
1355 uint Node::cmp( const Node &n ) const {
1356 return 1; // Must be same
1357 }
1358
1359 //------------------------------rematerialize-----------------------------------
1360 // Should we clone rather than spill this instruction?
1361 bool Node::rematerialize() const {
1362 if ( is_Mach() )
1363 return this->as_Mach()->rematerialize();
1364 else
1365 return (_flags & Flag_rematerialize) != 0;
1366 }
1367
1368 //------------------------------needs_anti_dependence_check---------------------
1369 // Nodes which use memory without consuming it, hence need antidependences.
1370 bool Node::needs_anti_dependence_check() const {
1371 if( req() < 2 || (_flags & Flag_needs_anti_dependence_check) == 0 )
1372 return false;
1373 else
1374 return in(1)->bottom_type()->has_memory();
1375 }
1376
1377
1378 // Get an integer constant from a ConNode (or CastIINode).
1379 // Return a default value if there is no apparent constant here.
1380 const TypeInt* Node::find_int_type() const {
1381 if (this->is_Type()) {
1382 return this->as_Type()->type()->isa_int();
1383 } else if (this->is_Con()) {
1384 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1385 return this->bottom_type()->isa_int();
1386 }
1387 return NULL;
1388 }
1389
1390 // Get a pointer constant from a ConstNode.
1391 // Returns the constant if it is a pointer ConstNode
1392 intptr_t Node::get_ptr() const {
1393 assert( Opcode() == Op_ConP, "" );
1394 return ((ConPNode*)this)->type()->is_ptr()->get_con();
1395 }
1396
1397 // Get a narrow oop constant from a ConNNode.
1398 intptr_t Node::get_narrowcon() const {
1399 assert( Opcode() == Op_ConN, "" );
1400 return ((ConNNode*)this)->type()->is_narrowoop()->get_con();
1401 }
1402
1403 // Get a long constant from a ConNode.
1404 // Return a default value if there is no apparent constant here.
1405 const TypeLong* Node::find_long_type() const {
1406 if (this->is_Type()) {
1407 return this->as_Type()->type()->isa_long();
1408 } else if (this->is_Con()) {
1409 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1410 return this->bottom_type()->isa_long();
1411 }
1412 return NULL;
1413 }
1414
1415
1416 /**
1417 * Return a ptr type for nodes which should have it.
1418 */
1419 const TypePtr* Node::get_ptr_type() const {
1420 const TypePtr* tp = this->bottom_type()->make_ptr();
1421 #ifdef ASSERT
1422 if (tp == NULL) {
1423 this->dump(1);
1424 assert((tp != NULL), "unexpected node type");
1425 }
1426 #endif
1427 return tp;
1428 }
1429
1430 // Get a double constant from a ConstNode.
1431 // Returns the constant if it is a double ConstNode
1432 jdouble Node::getd() const {
1433 assert( Opcode() == Op_ConD, "" );
1434 return ((ConDNode*)this)->type()->is_double_constant()->getd();
1435 }
1436
1437 // Get a float constant from a ConstNode.
1438 // Returns the constant if it is a float ConstNode
1439 jfloat Node::getf() const {
1440 assert( Opcode() == Op_ConF, "" );
1441 return ((ConFNode*)this)->type()->is_float_constant()->getf();
1442 }
1443
1444 #ifndef PRODUCT
1445
1446 //----------------------------NotANode----------------------------------------
1447 // Used in debugging code to avoid walking across dead or uninitialized edges.
1448 static inline bool NotANode(const Node* n) {
1449 if (n == NULL) return true;
1450 if (((intptr_t)n & 1) != 0) return true; // uninitialized, etc.
1451 if (*(address*)n == badAddress) return true; // kill by Node::destruct
1452 return false;
1453 }
1454
1455
1456 //------------------------------find------------------------------------------
1457 // Find a neighbor of this Node with the given _idx
1458 // If idx is negative, find its absolute value, following both _in and _out.
1459 static void find_recur(Compile* C, Node* &result, Node *n, int idx, bool only_ctrl,
1460 VectorSet* old_space, VectorSet* new_space ) {
1461 int node_idx = (idx >= 0) ? idx : -idx;
1462 if (NotANode(n)) return; // Gracefully handle NULL, -1, 0xabababab, etc.
1463 // Contained in new_space or old_space? Check old_arena first since it's mostly empty.
1464 VectorSet *v = C->old_arena()->contains(n) ? old_space : new_space;
1465 if( v->test(n->_idx) ) return;
1466 if( (int)n->_idx == node_idx
1467 debug_only(|| n->debug_idx() == node_idx) ) {
1468 if (result != NULL)
1469 tty->print("find: " INTPTR_FORMAT " and " INTPTR_FORMAT " both have idx==%d\n",
1470 (uintptr_t)result, (uintptr_t)n, node_idx);
1471 result = n;
1472 }
1473 v->set(n->_idx);
1474 for( uint i=0; i<n->len(); i++ ) {
1475 if( only_ctrl && !(n->is_Region()) && (n->Opcode() != Op_Root) && (i != TypeFunc::Control) ) continue;
1476 find_recur(C, result, n->in(i), idx, only_ctrl, old_space, new_space );
1477 }
1478 // Search along forward edges also:
1479 if (idx < 0 && !only_ctrl) {
1480 for( uint j=0; j<n->outcnt(); j++ ) {
1481 find_recur(C, result, n->raw_out(j), idx, only_ctrl, old_space, new_space );
1482 }
1483 }
1484 #ifdef ASSERT
1485 // Search along debug_orig edges last, checking for cycles
1486 Node* orig = n->debug_orig();
1487 if (orig != NULL) {
1488 do {
1489 if (NotANode(orig)) break;
1490 find_recur(C, result, orig, idx, only_ctrl, old_space, new_space );
1491 orig = orig->debug_orig();
1492 } while (orig != NULL && orig != n->debug_orig());
1493 }
1494 #endif //ASSERT
1495 }
1496
1497 // call this from debugger:
1498 Node* find_node(Node* n, int idx) {
1499 return n->find(idx);
1500 }
1501
1502 //------------------------------find-------------------------------------------
1503 Node* Node::find(int idx) const {
1504 ResourceArea *area = Thread::current()->resource_area();
1505 VectorSet old_space(area), new_space(area);
1506 Node* result = NULL;
1507 find_recur(Compile::current(), result, (Node*) this, idx, false, &old_space, &new_space );
1508 return result;
1509 }
1510
1511 //------------------------------find_ctrl--------------------------------------
1512 // Find an ancestor to this node in the control history with given _idx
1513 Node* Node::find_ctrl(int idx) const {
1514 ResourceArea *area = Thread::current()->resource_area();
1515 VectorSet old_space(area), new_space(area);
1516 Node* result = NULL;
1517 find_recur(Compile::current(), result, (Node*) this, idx, true, &old_space, &new_space );
1518 return result;
1519 }
1520 #endif
1521
1522
1523
1524 #ifndef PRODUCT
1525
1526 // -----------------------------Name-------------------------------------------
1527 extern const char *NodeClassNames[];
1528 const char *Node::Name() const { return NodeClassNames[Opcode()]; }
1529
1530 static bool is_disconnected(const Node* n) {
1531 for (uint i = 0; i < n->req(); i++) {
1532 if (n->in(i) != NULL) return false;
1533 }
1534 return true;
1535 }
1536
1537 #ifdef ASSERT
1538 static void dump_orig(Node* orig, outputStream *st) {
1539 Compile* C = Compile::current();
1540 if (NotANode(orig)) orig = NULL;
1541 if (orig != NULL && !C->node_arena()->contains(orig)) orig = NULL;
1542 if (orig == NULL) return;
1543 st->print(" !orig=");
1544 Node* fast = orig->debug_orig(); // tortoise & hare algorithm to detect loops
1545 if (NotANode(fast)) fast = NULL;
1546 while (orig != NULL) {
1547 bool discon = is_disconnected(orig); // if discon, print [123] else 123
1548 if (discon) st->print("[");
1549 if (!Compile::current()->node_arena()->contains(orig))
1550 st->print("o");
1551 st->print("%d", orig->_idx);
1552 if (discon) st->print("]");
1553 orig = orig->debug_orig();
1554 if (NotANode(orig)) orig = NULL;
1555 if (orig != NULL && !C->node_arena()->contains(orig)) orig = NULL;
1556 if (orig != NULL) st->print(",");
1557 if (fast != NULL) {
1558 // Step fast twice for each single step of orig:
1559 fast = fast->debug_orig();
1560 if (NotANode(fast)) fast = NULL;
1561 if (fast != NULL && fast != orig) {
1562 fast = fast->debug_orig();
1563 if (NotANode(fast)) fast = NULL;
1564 }
1565 if (fast == orig) {
1566 st->print("...");
1567 break;
1568 }
1569 }
1570 }
1571 }
1572
1573 void Node::set_debug_orig(Node* orig) {
1574 _debug_orig = orig;
1575 if (BreakAtNode == 0) return;
1576 if (NotANode(orig)) orig = NULL;
1577 int trip = 10;
1578 while (orig != NULL) {
1579 if (orig->debug_idx() == BreakAtNode || (int)orig->_idx == BreakAtNode) {
1580 tty->print_cr("BreakAtNode: _idx=%d _debug_idx=%d orig._idx=%d orig._debug_idx=%d",
1581 this->_idx, this->debug_idx(), orig->_idx, orig->debug_idx());
1582 BREAKPOINT;
1583 }
1584 orig = orig->debug_orig();
1585 if (NotANode(orig)) orig = NULL;
1586 if (trip-- <= 0) break;
1587 }
1588 }
1589 #endif //ASSERT
1590
1591 //------------------------------dump------------------------------------------
1592 // Dump a Node
1593 void Node::dump(const char* suffix, outputStream *st) const {
1594 Compile* C = Compile::current();
1595 bool is_new = C->node_arena()->contains(this);
1596 C->_in_dump_cnt++;
1597 st->print("%c%d\t%s\t=== ", is_new ? ' ' : 'o', _idx, Name());
1598
1599 // Dump the required and precedence inputs
1600 dump_req(st);
1601 dump_prec(st);
1602 // Dump the outputs
1603 dump_out(st);
1604
1605 if (is_disconnected(this)) {
1606 #ifdef ASSERT
1607 st->print(" [%d]",debug_idx());
1608 dump_orig(debug_orig(), st);
1609 #endif
1610 st->cr();
1611 C->_in_dump_cnt--;
1612 return; // don't process dead nodes
1613 }
1614
1615 // Dump node-specific info
1616 dump_spec(st);
1617 #ifdef ASSERT
1618 // Dump the non-reset _debug_idx
1619 if (Verbose && WizardMode) {
1620 st->print(" [%d]",debug_idx());
1621 }
1622 #endif
1623
1624 const Type *t = bottom_type();
1625
1626 if (t != NULL && (t->isa_instptr() || t->isa_klassptr())) {
1627 const TypeInstPtr *toop = t->isa_instptr();
1628 const TypeKlassPtr *tkls = t->isa_klassptr();
1629 ciKlass* klass = toop ? toop->klass() : (tkls ? tkls->klass() : NULL );
1630 if (klass && klass->is_loaded() && klass->is_interface()) {
1631 st->print(" Interface:");
1632 } else if (toop) {
1633 st->print(" Oop:");
1634 } else if (tkls) {
1635 st->print(" Klass:");
1636 }
1637 t->dump_on(st);
1638 } else if (t == Type::MEMORY) {
1639 st->print(" Memory:");
1640 MemNode::dump_adr_type(this, adr_type(), st);
1641 } else if (Verbose || WizardMode) {
1642 st->print(" Type:");
1643 if (t) {
1644 t->dump_on(st);
1645 } else {
1646 st->print("no type");
1647 }
1648 } else if (t->isa_vect() && this->is_MachSpillCopy()) {
1649 // Dump MachSpillcopy vector type.
1650 t->dump_on(st);
1651 }
1652 if (is_new) {
1653 debug_only(dump_orig(debug_orig(), st));
1654 Node_Notes* nn = C->node_notes_at(_idx);
1655 if (nn != NULL && !nn->is_clear()) {
1656 if (nn->jvms() != NULL) {
1657 st->print(" !jvms:");
1658 nn->jvms()->dump_spec(st);
1659 }
1660 }
1661 }
1662 if (suffix) st->print(suffix);
1663 C->_in_dump_cnt--;
1664 }
1665
1666 //------------------------------dump_req--------------------------------------
1667 void Node::dump_req(outputStream *st) const {
1668 // Dump the required input edges
1669 for (uint i = 0; i < req(); i++) { // For all required inputs
1670 Node* d = in(i);
1671 if (d == NULL) {
1672 st->print("_ ");
1673 } else if (NotANode(d)) {
1674 st->print("NotANode "); // uninitialized, sentinel, garbage, etc.
1675 } else {
1676 st->print("%c%d ", Compile::current()->node_arena()->contains(d) ? ' ' : 'o', d->_idx);
1677 }
1678 }
1679 }
1680
1681
1682 //------------------------------dump_prec-------------------------------------
1683 void Node::dump_prec(outputStream *st) const {
1684 // Dump the precedence edges
1685 int any_prec = 0;
1686 for (uint i = req(); i < len(); i++) { // For all precedence inputs
1687 Node* p = in(i);
1688 if (p != NULL) {
1689 if (!any_prec++) st->print(" |");
1690 if (NotANode(p)) { st->print("NotANode "); continue; }
1691 st->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
1692 }
1693 }
1694 }
1695
1696 //------------------------------dump_out--------------------------------------
1697 void Node::dump_out(outputStream *st) const {
1698 // Delimit the output edges
1699 st->print(" [[");
1700 // Dump the output edges
1701 for (uint i = 0; i < _outcnt; i++) { // For all outputs
1702 Node* u = _out[i];
1703 if (u == NULL) {
1704 st->print("_ ");
1705 } else if (NotANode(u)) {
1706 st->print("NotANode ");
1707 } else {
1708 st->print("%c%d ", Compile::current()->node_arena()->contains(u) ? ' ' : 'o', u->_idx);
1709 }
1710 }
1711 st->print("]] ");
1712 }
1713
1714 //------------------------------dump_nodes-------------------------------------
1715 static void dump_nodes(const Node* start, int d, bool only_ctrl) {
1716 Node* s = (Node*)start; // remove const
1717 if (NotANode(s)) return;
1718
1719 uint depth = (uint)ABS(d);
1720 int direction = d;
1721 Compile* C = Compile::current();
1722 GrowableArray <Node *> nstack(C->unique());
1723
1724 nstack.append(s);
1725 int begin = 0;
1726 int end = 0;
1727 for(uint i = 0; i < depth; i++) {
1728 end = nstack.length();
1729 for(int j = begin; j < end; j++) {
1730 Node* tp = nstack.at(j);
1731 uint limit = direction > 0 ? tp->len() : tp->outcnt();
1732 for(uint k = 0; k < limit; k++) {
1733 Node* n = direction > 0 ? tp->in(k) : tp->raw_out(k);
1734
1735 if (NotANode(n)) continue;
1736 // do not recurse through top or the root (would reach unrelated stuff)
1737 if (n->is_Root() || n->is_top()) continue;
1738 if (only_ctrl && !n->is_CFG()) continue;
1739
1740 bool on_stack = nstack.contains(n);
1741 if (!on_stack) {
1742 nstack.append(n);
1743 }
1744 }
1745 }
1746 begin = end;
1747 }
1748 end = nstack.length();
1749 if (direction > 0) {
1750 for(int j = end-1; j >= 0; j--) {
1751 nstack.at(j)->dump();
1752 }
1753 } else {
1754 for(int j = 0; j < end; j++) {
1755 nstack.at(j)->dump();
1756 }
1757 }
1758 }
1759
1760 //------------------------------dump-------------------------------------------
1761 void Node::dump(int d) const {
1762 dump_nodes(this, d, false);
1763 }
1764
1765 //------------------------------dump_ctrl--------------------------------------
1766 // Dump a Node's control history to depth
1767 void Node::dump_ctrl(int d) const {
1768 dump_nodes(this, d, true);
1769 }
1770
1771 // VERIFICATION CODE
1772 // For each input edge to a node (ie - for each Use-Def edge), verify that
1773 // there is a corresponding Def-Use edge.
1774 //------------------------------verify_edges-----------------------------------
1775 void Node::verify_edges(Unique_Node_List &visited) {
1776 uint i, j, idx;
1777 int cnt;
1778 Node *n;
1779
1780 // Recursive termination test
1781 if (visited.member(this)) return;
1782 visited.push(this);
1783
1784 // Walk over all input edges, checking for correspondence
1785 for( i = 0; i < len(); i++ ) {
1786 n = in(i);
1787 if (n != NULL && !n->is_top()) {
1788 // Count instances of (Node *)this
1789 cnt = 0;
1790 for (idx = 0; idx < n->_outcnt; idx++ ) {
1791 if (n->_out[idx] == (Node *)this) cnt++;
1792 }
1793 assert( cnt > 0,"Failed to find Def-Use edge." );
1794 // Check for duplicate edges
1795 // walk the input array downcounting the input edges to n
1796 for( j = 0; j < len(); j++ ) {
1797 if( in(j) == n ) cnt--;
1798 }
1799 assert( cnt == 0,"Mismatched edge count.");
1800 } else if (n == NULL) {
1801 assert(i >= req() || i == 0 || is_Region() || is_Phi(), "only regions or phis have null data edges");
1802 } else {
1803 assert(n->is_top(), "sanity");
1804 // Nothing to check.
1805 }
1806 }
1807 // Recursive walk over all input edges
1808 for( i = 0; i < len(); i++ ) {
1809 n = in(i);
1810 if( n != NULL )
1811 in(i)->verify_edges(visited);
1812 }
1813 }
1814
1815 //------------------------------verify_recur-----------------------------------
1816 static const Node *unique_top = NULL;
1817
1818 void Node::verify_recur(const Node *n, int verify_depth,
1819 VectorSet &old_space, VectorSet &new_space) {
1820 if ( verify_depth == 0 ) return;
1821 if (verify_depth > 0) --verify_depth;
1822
1823 Compile* C = Compile::current();
1824
1825 // Contained in new_space or old_space?
1826 VectorSet *v = C->node_arena()->contains(n) ? &new_space : &old_space;
1827 // Check for visited in the proper space. Numberings are not unique
1828 // across spaces so we need a separate VectorSet for each space.
1829 if( v->test_set(n->_idx) ) return;
1830
1831 if (n->is_Con() && n->bottom_type() == Type::TOP) {
1832 if (C->cached_top_node() == NULL)
1833 C->set_cached_top_node((Node*)n);
1834 assert(C->cached_top_node() == n, "TOP node must be unique");
1835 }
1836
1837 for( uint i = 0; i < n->len(); i++ ) {
1838 Node *x = n->in(i);
1839 if (!x || x->is_top()) continue;
1840
1841 // Verify my input has a def-use edge to me
1842 if (true /*VerifyDefUse*/) {
1843 // Count use-def edges from n to x
1844 int cnt = 0;
1845 for( uint j = 0; j < n->len(); j++ )
1846 if( n->in(j) == x )
1847 cnt++;
1848 // Count def-use edges from x to n
1849 uint max = x->_outcnt;
1850 for( uint k = 0; k < max; k++ )
1851 if (x->_out[k] == n)
1852 cnt--;
1853 assert( cnt == 0, "mismatched def-use edge counts" );
1854 }
1855
1856 verify_recur(x, verify_depth, old_space, new_space);
1857 }
1858
1859 }
1860
1861 //------------------------------verify-----------------------------------------
1862 // Check Def-Use info for my subgraph
1863 void Node::verify() const {
1864 Compile* C = Compile::current();
1865 Node* old_top = C->cached_top_node();
1866 ResourceMark rm;
1867 ResourceArea *area = Thread::current()->resource_area();
1868 VectorSet old_space(area), new_space(area);
1869 verify_recur(this, -1, old_space, new_space);
1870 C->set_cached_top_node(old_top);
1871 }
1872 #endif
1873
1874
1875 //------------------------------walk-------------------------------------------
1876 // Graph walk, with both pre-order and post-order functions
1877 void Node::walk(NFunc pre, NFunc post, void *env) {
1878 VectorSet visited(Thread::current()->resource_area()); // Setup for local walk
1879 walk_(pre, post, env, visited);
1880 }
1881
1882 void Node::walk_(NFunc pre, NFunc post, void *env, VectorSet &visited) {
1883 if( visited.test_set(_idx) ) return;
1884 pre(*this,env); // Call the pre-order walk function
1885 for( uint i=0; i<_max; i++ )
1886 if( in(i) ) // Input exists and is not walked?
1887 in(i)->walk_(pre,post,env,visited); // Walk it with pre & post functions
1888 post(*this,env); // Call the post-order walk function
1889 }
1890
1891 void Node::nop(Node &, void*) {}
1892
1893 //------------------------------Registers--------------------------------------
1894 // Do we Match on this edge index or not? Generally false for Control
1895 // and true for everything else. Weird for calls & returns.
1896 uint Node::match_edge(uint idx) const {
1897 return idx; // True for other than index 0 (control)
1898 }
1899
1900 // Register classes are defined for specific machines
1901 const RegMask &Node::out_RegMask() const {
1902 ShouldNotCallThis();
1903 return *(new RegMask());
1904 }
1905
1906 const RegMask &Node::in_RegMask(uint) const {
1907 ShouldNotCallThis();
1908 return *(new RegMask());
1909 }
1910
1911 //=============================================================================
1912 //-----------------------------------------------------------------------------
1913 void Node_Array::reset( Arena *new_arena ) {
1914 _a->Afree(_nodes,_max*sizeof(Node*));
1915 _max = 0;
1916 _nodes = NULL;
1917 _a = new_arena;
1918 }
1919
1920 //------------------------------clear------------------------------------------
1921 // Clear all entries in _nodes to NULL but keep storage
1922 void Node_Array::clear() {
1923 Copy::zero_to_bytes( _nodes, _max*sizeof(Node*) );
1924 }
1925
1926 //-----------------------------------------------------------------------------
1927 void Node_Array::grow( uint i ) {
1928 if( !_max ) {
1929 _max = 1;
1930 _nodes = (Node**)_a->Amalloc( _max * sizeof(Node*) );
1931 _nodes[0] = NULL;
1932 }
1933 uint old = _max;
1934 while( i >= _max ) _max <<= 1; // Double to fit
1935 _nodes = (Node**)_a->Arealloc( _nodes, old*sizeof(Node*),_max*sizeof(Node*));
1936 Copy::zero_to_bytes( &_nodes[old], (_max-old)*sizeof(Node*) );
1937 }
1938
1939 //-----------------------------------------------------------------------------
1940 void Node_Array::insert( uint i, Node *n ) {
1941 if( _nodes[_max-1] ) grow(_max); // Get more space if full
1942 Copy::conjoint_words_to_higher((HeapWord*)&_nodes[i], (HeapWord*)&_nodes[i+1], ((_max-i-1)*sizeof(Node*)));
1943 _nodes[i] = n;
1944 }
1945
1946 //-----------------------------------------------------------------------------
1947 void Node_Array::remove( uint i ) {
1948 Copy::conjoint_words_to_lower((HeapWord*)&_nodes[i+1], (HeapWord*)&_nodes[i], ((_max-i-1)*sizeof(Node*)));
1949 _nodes[_max-1] = NULL;
1950 }
1951
1952 //-----------------------------------------------------------------------------
1953 void Node_Array::sort( C_sort_func_t func) {
1954 qsort( _nodes, _max, sizeof( Node* ), func );
1955 }
1956
1957 //-----------------------------------------------------------------------------
1958 void Node_Array::dump() const {
1959 #ifndef PRODUCT
1960 for( uint i = 0; i < _max; i++ ) {
1961 Node *nn = _nodes[i];
1962 if( nn != NULL ) {
1963 tty->print("%5d--> ",i); nn->dump();
1964 }
1965 }
1966 #endif
1967 }
1968
1969 //--------------------------is_iteratively_computed------------------------------
1970 // Operation appears to be iteratively computed (such as an induction variable)
1971 // It is possible for this operation to return false for a loop-varying
1972 // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1973 bool Node::is_iteratively_computed() {
1974 if (ideal_reg()) { // does operation have a result register?
1975 for (uint i = 1; i < req(); i++) {
1976 Node* n = in(i);
1977 if (n != NULL && n->is_Phi()) {
1978 for (uint j = 1; j < n->req(); j++) {
1979 if (n->in(j) == this) {
1980 return true;
1981 }
1982 }
1983 }
1984 }
1985 }
1986 return false;
1987 }
1988
1989 //--------------------------find_similar------------------------------
1990 // Return a node with opcode "opc" and same inputs as "this" if one can
1991 // be found; Otherwise return NULL;
1992 Node* Node::find_similar(int opc) {
1993 if (req() >= 2) {
1994 Node* def = in(1);
1995 if (def && def->outcnt() >= 2) {
1996 for (DUIterator_Fast dmax, i = def->fast_outs(dmax); i < dmax; i++) {
1997 Node* use = def->fast_out(i);
1998 if (use->Opcode() == opc &&
1999 use->req() == req()) {
2000 uint j;
2001 for (j = 0; j < use->req(); j++) {
2002 if (use->in(j) != in(j)) {
2003 break;
2004 }
2005 }
2006 if (j == use->req()) {
2007 return use;
2008 }
2009 }
2010 }
2011 }
2012 }
2013 return NULL;
2014 }
2015
2016
2017 //--------------------------unique_ctrl_out------------------------------
2018 // Return the unique control out if only one. Null if none or more than one.
2019 Node* Node::unique_ctrl_out() {
2020 Node* found = NULL;
2021 for (uint i = 0; i < outcnt(); i++) {
2022 Node* use = raw_out(i);
2023 if (use->is_CFG() && use != this) {
2024 if (found != NULL) return NULL;
2025 found = use;
2026 }
2027 }
2028 return found;
2029 }
2030
2031 //=============================================================================
2032 //------------------------------yank-------------------------------------------
2033 // Find and remove
2034 void Node_List::yank( Node *n ) {
2035 uint i;
2036 for( i = 0; i < _cnt; i++ )
2037 if( _nodes[i] == n )
2038 break;
2039
2040 if( i < _cnt )
2041 _nodes[i] = _nodes[--_cnt];
2042 }
2043
2044 //------------------------------dump-------------------------------------------
2045 void Node_List::dump() const {
2046 #ifndef PRODUCT
2047 for( uint i = 0; i < _cnt; i++ )
2048 if( _nodes[i] ) {
2049 tty->print("%5d--> ",i);
2050 _nodes[i]->dump();
2051 }
2052 #endif
2053 }
2054
2055 //=============================================================================
2056 //------------------------------remove-----------------------------------------
2057 void Unique_Node_List::remove( Node *n ) {
2058 if( _in_worklist[n->_idx] ) {
2059 for( uint i = 0; i < size(); i++ )
2060 if( _nodes[i] == n ) {
2061 map(i,Node_List::pop());
2062 _in_worklist >>= n->_idx;
2063 return;
2064 }
2065 ShouldNotReachHere();
2066 }
2067 }
2068
2069 //-----------------------remove_useless_nodes----------------------------------
2070 // Remove useless nodes from worklist
2071 void Unique_Node_List::remove_useless_nodes(VectorSet &useful) {
2072
2073 for( uint i = 0; i < size(); ++i ) {
2074 Node *n = at(i);
2075 assert( n != NULL, "Did not expect null entries in worklist");
2076 if( ! useful.test(n->_idx) ) {
2077 _in_worklist >>= n->_idx;
2078 map(i,Node_List::pop());
2079 // Node *replacement = Node_List::pop();
2080 // if( i != size() ) { // Check if removing last entry
2081 // _nodes[i] = replacement;
2082 // }
2083 --i; // Visit popped node
2084 // If it was last entry, loop terminates since size() was also reduced
2085 }
2086 }
2087 }
2088
2089 //=============================================================================
2090 void Node_Stack::grow() {
2091 size_t old_top = pointer_delta(_inode_top,_inodes,sizeof(INode)); // save _top
2092 size_t old_max = pointer_delta(_inode_max,_inodes,sizeof(INode));
2093 size_t max = old_max << 1; // max * 2
2094 _inodes = REALLOC_ARENA_ARRAY(_a, INode, _inodes, old_max, max);
2095 _inode_max = _inodes + max;
2096 _inode_top = _inodes + old_top; // restore _top
2097 }
2098
2099 // Node_Stack is used to map nodes.
2100 Node* Node_Stack::find(uint idx) const {
2101 uint sz = size();
2102 for (uint i=0; i < sz; i++) {
2103 if (idx == index_at(i) )
2104 return node_at(i);
2105 }
2106 return NULL;
2107 }
2108
2109 //=============================================================================
2110 uint TypeNode::size_of() const { return sizeof(*this); }
2111 #ifndef PRODUCT
2112 void TypeNode::dump_spec(outputStream *st) const {
2113 if( !Verbose && !WizardMode ) {
2114 // standard dump does this in Verbose and WizardMode
2115 st->print(" #"); _type->dump_on(st);
2116 }
2117 }
2118 #endif
2119 uint TypeNode::hash() const {
2120 return Node::hash() + _type->hash();
2121 }
2122 uint TypeNode::cmp( const Node &n ) const
2123 { return !Type::cmp( _type, ((TypeNode&)n)._type ); }
2124 const Type *TypeNode::bottom_type() const { return _type; }
2125 const Type *TypeNode::Value( PhaseTransform * ) const { return _type; }
2126
2127 //------------------------------ideal_reg--------------------------------------
2128 uint TypeNode::ideal_reg() const {
2129 return Matcher::base2reg[_type->base()];
2130 }