1 /*
2 * Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2024, 2025, Alibaba Group Holding Limited. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "gc/shared/barrierSet.hpp"
27 #include "gc/shared/c2/barrierSetC2.hpp"
28 #include "libadt/vectset.hpp"
29 #include "memory/allocation.inline.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "opto/ad.hpp"
32 #include "opto/callGenerator.hpp"
33 #include "opto/castnode.hpp"
34 #include "opto/cfgnode.hpp"
35 #include "opto/connode.hpp"
36 #include "opto/inlinetypenode.hpp"
37 #include "opto/loopnode.hpp"
38 #include "opto/machnode.hpp"
39 #include "opto/matcher.hpp"
40 #include "opto/node.hpp"
41 #include "opto/opcodes.hpp"
42 #include "opto/regmask.hpp"
43 #include "opto/rootnode.hpp"
44 #include "opto/type.hpp"
45 #include "utilities/copy.hpp"
46 #include "utilities/macros.hpp"
47 #include "utilities/powerOfTwo.hpp"
48 #include "utilities/stringUtils.hpp"
49
50 class RegMask;
51 // #include "phase.hpp"
52 class PhaseTransform;
53 class PhaseGVN;
54
55 // Arena we are currently building Nodes in
56 const uint Node::NotAMachineReg = 0xffff0000;
57
58 #ifndef PRODUCT
59 extern uint nodes_created;
60 #endif
61 #ifdef __clang__
62 #pragma clang diagnostic push
63 #pragma GCC diagnostic ignored "-Wuninitialized"
64 #endif
65
66 #ifdef ASSERT
67
68 //-------------------------- construct_node------------------------------------
69 // Set a breakpoint here to identify where a particular node index is built.
70 void Node::verify_construction() {
71 _debug_orig = nullptr;
72 // The decimal digits of _debug_idx are <compile_id> followed by 10 digits of <_idx>
73 Compile* C = Compile::current();
74 assert(C->unique() < (INT_MAX - 1), "Node limit exceeded INT_MAX");
75 uint64_t new_debug_idx = (uint64_t)C->compile_id() * 10000000000 + _idx;
76 set_debug_idx(new_debug_idx);
77 if (!C->phase_optimize_finished()) {
78 // Only check assert during parsing and optimization phase. Skip it while generating code.
79 assert(C->live_nodes() <= C->max_node_limit(), "Live Node limit exceeded limit");
80 }
81 if (BreakAtNode != 0 && (_debug_idx == BreakAtNode || (uint64_t)_idx == BreakAtNode)) {
82 tty->print_cr("BreakAtNode: _idx=%d _debug_idx=" UINT64_FORMAT, _idx, _debug_idx);
83 BREAKPOINT;
84 }
85 #if OPTO_DU_ITERATOR_ASSERT
86 _last_del = nullptr;
87 _del_tick = 0;
88 #endif
89 _hash_lock = 0;
90 }
91
92
93 // #ifdef ASSERT ...
94
95 #if OPTO_DU_ITERATOR_ASSERT
96 void DUIterator_Common::sample(const Node* node) {
97 _vdui = VerifyDUIterators;
98 _node = node;
99 _outcnt = node->_outcnt;
100 _del_tick = node->_del_tick;
101 _last = nullptr;
102 }
103
104 void DUIterator_Common::verify(const Node* node, bool at_end_ok) {
105 assert(_node == node, "consistent iterator source");
106 assert(_del_tick == node->_del_tick, "no unexpected deletions allowed");
107 }
108
109 void DUIterator_Common::verify_resync() {
110 // Ensure that the loop body has just deleted the last guy produced.
111 const Node* node = _node;
112 // Ensure that at least one copy of the last-seen edge was deleted.
113 // Note: It is OK to delete multiple copies of the last-seen edge.
114 // Unfortunately, we have no way to verify that all the deletions delete
115 // that same edge. On this point we must use the Honor System.
116 assert(node->_del_tick >= _del_tick+1, "must have deleted an edge");
117 assert(node->_last_del == _last, "must have deleted the edge just produced");
118 // We liked this deletion, so accept the resulting outcnt and tick.
119 _outcnt = node->_outcnt;
120 _del_tick = node->_del_tick;
121 }
122
123 void DUIterator_Common::reset(const DUIterator_Common& that) {
124 if (this == &that) return; // ignore assignment to self
125 if (!_vdui) {
126 // We need to initialize everything, overwriting garbage values.
127 _last = that._last;
128 _vdui = that._vdui;
129 }
130 // Note: It is legal (though odd) for an iterator over some node x
131 // to be reassigned to iterate over another node y. Some doubly-nested
132 // progress loops depend on being able to do this.
133 const Node* node = that._node;
134 // Re-initialize everything, except _last.
135 _node = node;
136 _outcnt = node->_outcnt;
137 _del_tick = node->_del_tick;
138 }
139
140 void DUIterator::sample(const Node* node) {
141 DUIterator_Common::sample(node); // Initialize the assertion data.
142 _refresh_tick = 0; // No refreshes have happened, as yet.
143 }
144
145 void DUIterator::verify(const Node* node, bool at_end_ok) {
146 DUIterator_Common::verify(node, at_end_ok);
147 assert(_idx < node->_outcnt + (uint)at_end_ok, "idx in range");
148 }
149
150 void DUIterator::verify_increment() {
151 if (_refresh_tick & 1) {
152 // We have refreshed the index during this loop.
153 // Fix up _idx to meet asserts.
154 if (_idx > _outcnt) _idx = _outcnt;
155 }
156 verify(_node, true);
157 }
158
159 void DUIterator::verify_resync() {
160 // Note: We do not assert on _outcnt, because insertions are OK here.
161 DUIterator_Common::verify_resync();
162 // Make sure we are still in sync, possibly with no more out-edges:
163 verify(_node, true);
164 }
165
166 void DUIterator::reset(const DUIterator& that) {
167 if (this == &that) return; // self assignment is always a no-op
168 assert(that._refresh_tick == 0, "assign only the result of Node::outs()");
169 assert(that._idx == 0, "assign only the result of Node::outs()");
170 assert(_idx == that._idx, "already assigned _idx");
171 if (!_vdui) {
172 // We need to initialize everything, overwriting garbage values.
173 sample(that._node);
174 } else {
175 DUIterator_Common::reset(that);
176 if (_refresh_tick & 1) {
177 _refresh_tick++; // Clear the "was refreshed" flag.
178 }
179 assert(_refresh_tick < 2*100000, "DU iteration must converge quickly");
180 }
181 }
182
183 void DUIterator::refresh() {
184 DUIterator_Common::sample(_node); // Re-fetch assertion data.
185 _refresh_tick |= 1; // Set the "was refreshed" flag.
186 }
187
188 void DUIterator::verify_finish() {
189 // If the loop has killed the node, do not require it to re-run.
190 if (_node->_outcnt == 0) _refresh_tick &= ~1;
191 // If this assert triggers, it means that a loop used refresh_out_pos
192 // to re-synch an iteration index, but the loop did not correctly
193 // re-run itself, using a "while (progress)" construct.
194 // This iterator enforces the rule that you must keep trying the loop
195 // until it "runs clean" without any need for refreshing.
196 assert(!(_refresh_tick & 1), "the loop must run once with no refreshing");
197 }
198
199
200 void DUIterator_Fast::verify(const Node* node, bool at_end_ok) {
201 DUIterator_Common::verify(node, at_end_ok);
202 Node** out = node->_out;
203 uint cnt = node->_outcnt;
204 assert(cnt == _outcnt, "no insertions allowed");
205 assert(_outp >= out && _outp <= out + cnt - !at_end_ok, "outp in range");
206 // This last check is carefully designed to work for NO_OUT_ARRAY.
207 }
208
209 void DUIterator_Fast::verify_limit() {
210 const Node* node = _node;
211 verify(node, true);
212 assert(_outp == node->_out + node->_outcnt, "limit still correct");
213 }
214
215 void DUIterator_Fast::verify_resync() {
216 const Node* node = _node;
217 if (_outp == node->_out + _outcnt) {
218 // Note that the limit imax, not the pointer i, gets updated with the
219 // exact count of deletions. (For the pointer it's always "--i".)
220 assert(node->_outcnt+node->_del_tick == _outcnt+_del_tick, "no insertions allowed with deletion(s)");
221 // This is a limit pointer, with a name like "imax".
222 // Fudge the _last field so that the common assert will be happy.
223 _last = (Node*) node->_last_del;
224 DUIterator_Common::verify_resync();
225 } else {
226 assert(node->_outcnt < _outcnt, "no insertions allowed with deletion(s)");
227 // A normal internal pointer.
228 DUIterator_Common::verify_resync();
229 // Make sure we are still in sync, possibly with no more out-edges:
230 verify(node, true);
231 }
232 }
233
234 void DUIterator_Fast::verify_relimit(uint n) {
235 const Node* node = _node;
236 assert((int)n > 0, "use imax -= n only with a positive count");
237 // This must be a limit pointer, with a name like "imax".
238 assert(_outp == node->_out + node->_outcnt, "apply -= only to a limit (imax)");
239 // The reported number of deletions must match what the node saw.
240 assert(node->_del_tick == _del_tick + n, "must have deleted n edges");
241 // Fudge the _last field so that the common assert will be happy.
242 _last = (Node*) node->_last_del;
243 DUIterator_Common::verify_resync();
244 }
245
246 void DUIterator_Fast::reset(const DUIterator_Fast& that) {
247 assert(_outp == that._outp, "already assigned _outp");
248 DUIterator_Common::reset(that);
249 }
250
251 void DUIterator_Last::verify(const Node* node, bool at_end_ok) {
252 // at_end_ok means the _outp is allowed to underflow by 1
253 _outp += at_end_ok;
254 DUIterator_Fast::verify(node, at_end_ok); // check _del_tick, etc.
255 _outp -= at_end_ok;
256 assert(_outp == (node->_out + node->_outcnt) - 1, "pointer must point to end of nodes");
257 }
258
259 void DUIterator_Last::verify_limit() {
260 // Do not require the limit address to be resynched.
261 //verify(node, true);
262 assert(_outp == _node->_out, "limit still correct");
263 }
264
265 void DUIterator_Last::verify_step(uint num_edges) {
266 assert((int)num_edges > 0, "need non-zero edge count for loop progress");
267 _outcnt -= num_edges;
268 _del_tick += num_edges;
269 // Make sure we are still in sync, possibly with no more out-edges:
270 const Node* node = _node;
271 verify(node, true);
272 assert(node->_last_del == _last, "must have deleted the edge just produced");
273 }
274
275 #endif //OPTO_DU_ITERATOR_ASSERT
276
277
278 #endif //ASSERT
279
280
281 // This constant used to initialize _out may be any non-null value.
282 // The value null is reserved for the top node only.
283 #define NO_OUT_ARRAY ((Node**)-1)
284
285 // Out-of-line code from node constructors.
286 // Executed only when extra debug info. is being passed around.
287 static void init_node_notes(Compile* C, int idx, Node_Notes* nn) {
288 C->set_node_notes_at(idx, nn);
289 }
290
291 // Shared initialization code.
292 inline int Node::Init(int req) {
293 Compile* C = Compile::current();
294 int idx = C->next_unique();
295 NOT_PRODUCT(_igv_idx = C->next_igv_idx());
296
297 // Allocate memory for the necessary number of edges.
298 if (req > 0) {
299 // Allocate space for _in array to have double alignment.
300 _in = (Node **) ((char *) (C->node_arena()->AmallocWords(req * sizeof(void*))));
301 }
302 // If there are default notes floating around, capture them:
303 Node_Notes* nn = C->default_node_notes();
304 if (nn != nullptr) init_node_notes(C, idx, nn);
305
306 // Note: At this point, C is dead,
307 // and we begin to initialize the new Node.
308
309 _cnt = _max = req;
310 _outcnt = _outmax = 0;
311 _class_id = Class_Node;
312 _flags = 0;
313 _out = NO_OUT_ARRAY;
314 return idx;
315 }
316
317 //------------------------------Node-------------------------------------------
318 // Create a Node, with a given number of required edges.
319 Node::Node(uint req)
320 : _idx(Init(req))
321 #ifdef ASSERT
322 , _parse_idx(_idx)
323 #endif
324 {
325 assert( req < Compile::current()->max_node_limit() - NodeLimitFudgeFactor, "Input limit exceeded" );
326 DEBUG_ONLY( verify_construction() );
327 NOT_PRODUCT(nodes_created++);
328 if (req == 0) {
329 _in = nullptr;
330 } else {
331 Node** to = _in;
332 for(uint i = 0; i < req; i++) {
333 to[i] = nullptr;
334 }
335 }
336 }
337
338 //------------------------------Node-------------------------------------------
339 Node::Node(Node *n0)
340 : _idx(Init(1))
341 #ifdef ASSERT
342 , _parse_idx(_idx)
343 #endif
344 {
345 DEBUG_ONLY( verify_construction() );
346 NOT_PRODUCT(nodes_created++);
347 assert( is_not_dead(n0), "can not use dead node");
348 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
349 }
350
351 //------------------------------Node-------------------------------------------
352 Node::Node(Node *n0, Node *n1)
353 : _idx(Init(2))
354 #ifdef ASSERT
355 , _parse_idx(_idx)
356 #endif
357 {
358 DEBUG_ONLY( verify_construction() );
359 NOT_PRODUCT(nodes_created++);
360 assert( is_not_dead(n0), "can not use dead node");
361 assert( is_not_dead(n1), "can not use dead node");
362 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
363 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
364 }
365
366 //------------------------------Node-------------------------------------------
367 Node::Node(Node *n0, Node *n1, Node *n2)
368 : _idx(Init(3))
369 #ifdef ASSERT
370 , _parse_idx(_idx)
371 #endif
372 {
373 DEBUG_ONLY( verify_construction() );
374 NOT_PRODUCT(nodes_created++);
375 assert( is_not_dead(n0), "can not use dead node");
376 assert( is_not_dead(n1), "can not use dead node");
377 assert( is_not_dead(n2), "can not use dead node");
378 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
379 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
380 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
381 }
382
383 //------------------------------Node-------------------------------------------
384 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3)
385 : _idx(Init(4))
386 #ifdef ASSERT
387 , _parse_idx(_idx)
388 #endif
389 {
390 DEBUG_ONLY( verify_construction() );
391 NOT_PRODUCT(nodes_created++);
392 assert( is_not_dead(n0), "can not use dead node");
393 assert( is_not_dead(n1), "can not use dead node");
394 assert( is_not_dead(n2), "can not use dead node");
395 assert( is_not_dead(n3), "can not use dead node");
396 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
397 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
398 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
399 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
400 }
401
402 //------------------------------Node-------------------------------------------
403 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3, Node *n4)
404 : _idx(Init(5))
405 #ifdef ASSERT
406 , _parse_idx(_idx)
407 #endif
408 {
409 DEBUG_ONLY( verify_construction() );
410 NOT_PRODUCT(nodes_created++);
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 != nullptr) n0->add_out((Node *)this);
417 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
418 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
419 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
420 _in[4] = n4; if (n4 != nullptr) 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(Init(6))
427 #ifdef ASSERT
428 , _parse_idx(_idx)
429 #endif
430 {
431 DEBUG_ONLY( verify_construction() );
432 NOT_PRODUCT(nodes_created++);
433 assert( is_not_dead(n0), "can not use dead node");
434 assert( is_not_dead(n1), "can not use dead node");
435 assert( is_not_dead(n2), "can not use dead node");
436 assert( is_not_dead(n3), "can not use dead node");
437 assert( is_not_dead(n4), "can not use dead node");
438 assert( is_not_dead(n5), "can not use dead node");
439 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
440 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
441 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
442 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
443 _in[4] = n4; if (n4 != nullptr) n4->add_out((Node *)this);
444 _in[5] = n5; if (n5 != nullptr) n5->add_out((Node *)this);
445 }
446
447 //------------------------------Node-------------------------------------------
448 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
449 Node *n4, Node *n5, Node *n6)
450 : _idx(Init(7))
451 #ifdef ASSERT
452 , _parse_idx(_idx)
453 #endif
454 {
455 DEBUG_ONLY( verify_construction() );
456 NOT_PRODUCT(nodes_created++);
457 assert( is_not_dead(n0), "can not use dead node");
458 assert( is_not_dead(n1), "can not use dead node");
459 assert( is_not_dead(n2), "can not use dead node");
460 assert( is_not_dead(n3), "can not use dead node");
461 assert( is_not_dead(n4), "can not use dead node");
462 assert( is_not_dead(n5), "can not use dead node");
463 assert( is_not_dead(n6), "can not use dead node");
464 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
465 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
466 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
467 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
468 _in[4] = n4; if (n4 != nullptr) n4->add_out((Node *)this);
469 _in[5] = n5; if (n5 != nullptr) n5->add_out((Node *)this);
470 _in[6] = n6; if (n6 != nullptr) n6->add_out((Node *)this);
471 }
472
473 #ifdef __clang__
474 #pragma clang diagnostic pop
475 #endif
476
477
478 //------------------------------clone------------------------------------------
479 // Clone a Node.
480 Node *Node::clone() const {
481 Compile* C = Compile::current();
482 uint s = size_of(); // Size of inherited Node
483 Node *n = (Node*)C->node_arena()->AmallocWords(size_of() + _max*sizeof(Node*));
484 Copy::conjoint_words_to_lower((HeapWord*)this, (HeapWord*)n, s);
485 // Set the new input pointer array
486 n->_in = (Node**)(((char*)n)+s);
487 // Cannot share the old output pointer array, so kill it
488 n->_out = NO_OUT_ARRAY;
489 // And reset the counters to 0
490 n->_outcnt = 0;
491 n->_outmax = 0;
492 // Unlock this guy, since he is not in any hash table.
493 DEBUG_ONLY(n->_hash_lock = 0);
494 // Walk the old node's input list to duplicate its edges
495 uint i;
496 for( i = 0; i < len(); i++ ) {
497 Node *x = in(i);
498 n->_in[i] = x;
499 if (x != nullptr) x->add_out(n);
500 }
501 if (is_macro()) {
502 C->add_macro_node(n);
503 }
504 if (is_expensive()) {
505 C->add_expensive_node(n);
506 }
507 if (for_post_loop_opts_igvn()) {
508 // Don't add cloned node to Compile::_for_post_loop_opts_igvn list automatically.
509 // If it is applicable, it will happen anyway when the cloned node is registered with IGVN.
510 n->remove_flag(Node::NodeFlags::Flag_for_post_loop_opts_igvn);
511 }
512 if (for_merge_stores_igvn()) {
513 // Don't add cloned node to Compile::_for_merge_stores_igvn list automatically.
514 // If it is applicable, it will happen anyway when the cloned node is registered with IGVN.
515 n->remove_flag(Node::NodeFlags::Flag_for_merge_stores_igvn);
516 }
517 if (n->is_ParsePredicate()) {
518 C->add_parse_predicate(n->as_ParsePredicate());
519 }
520 if (n->is_OpaqueTemplateAssertionPredicate()) {
521 C->add_template_assertion_predicate_opaque(n->as_OpaqueTemplateAssertionPredicate());
522 }
523
524 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
525 bs->register_potential_barrier_node(n);
526
527 n->set_idx(C->next_unique()); // Get new unique index as well
528 NOT_PRODUCT(n->_igv_idx = C->next_igv_idx());
529 DEBUG_ONLY( n->verify_construction() );
530 NOT_PRODUCT(nodes_created++);
531 // Do not patch over the debug_idx of a clone, because it makes it
532 // impossible to break on the clone's moment of creation.
533 //DEBUG_ONLY( n->set_debug_idx( debug_idx() ) );
534
535 C->copy_node_notes_to(n, (Node*) this);
536
537 // MachNode clone
538 uint nopnds;
539 if (this->is_Mach() && (nopnds = this->as_Mach()->num_opnds()) > 0) {
540 MachNode *mach = n->as_Mach();
541 MachNode *mthis = this->as_Mach();
542 // Get address of _opnd_array.
543 // It should be the same offset since it is the clone of this node.
544 MachOper **from = mthis->_opnds;
545 MachOper **to = (MachOper **)((size_t)(&mach->_opnds) +
546 pointer_delta((const void*)from,
547 (const void*)(&mthis->_opnds), 1));
548 mach->_opnds = to;
549 for ( uint i = 0; i < nopnds; ++i ) {
550 to[i] = from[i]->clone();
551 }
552 }
553 if (this->is_MachProj()) {
554 // MachProjNodes contain register masks that may contain pointers to
555 // externally allocated memory. Make sure to use a proper constructor
556 // instead of just shallowly copying.
557 MachProjNode* mach = n->as_MachProj();
558 MachProjNode* mthis = this->as_MachProj();
559 new (&mach->_rout) RegMask(mthis->_rout);
560 }
561 if (n->is_Call()) {
562 // CallGenerator is linked to the original node.
563 CallGenerator* cg = n->as_Call()->generator();
564 if (cg != nullptr) {
565 CallGenerator* cloned_cg = cg->with_call_node(n->as_Call());
566 n->as_Call()->set_generator(cloned_cg);
567 }
568 }
569 if (n->is_SafePoint()) {
570 // Scalar replacement and macro expansion might modify the JVMState.
571 // Clone it to make sure it's not shared between SafePointNodes.
572 n->as_SafePoint()->clone_jvms(C);
573 n->as_SafePoint()->clone_replaced_nodes();
574 }
575 if (n->is_InlineType()) {
576 C->add_inline_type(n);
577 }
578 if (n->is_LoadFlat() || n->is_StoreFlat()) {
579 C->add_flat_access(n);
580 }
581 Compile::current()->record_modified_node(n);
582 return n; // Return the clone
583 }
584
585 //---------------------------setup_is_top--------------------------------------
586 // Call this when changing the top node, to reassert the invariants
587 // required by Node::is_top. See Compile::set_cached_top_node.
588 void Node::setup_is_top() {
589 if (this == (Node*)Compile::current()->top()) {
590 // This node has just become top. Kill its out array.
591 _outcnt = _outmax = 0;
592 _out = nullptr; // marker value for top
593 assert(is_top(), "must be top");
594 } else {
595 if (_out == nullptr) _out = NO_OUT_ARRAY;
596 assert(!is_top(), "must not be top");
597 }
598 }
599
600 //------------------------------~Node------------------------------------------
601 // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
602 void Node::destruct(PhaseValues* phase) {
603 Compile* compile = (phase != nullptr) ? phase->C : Compile::current();
604 if (phase != nullptr && phase->is_IterGVN()) {
605 phase->is_IterGVN()->_worklist.remove(this);
606 }
607 // If this is the most recently created node, reclaim its index. Otherwise,
608 // record the node as dead to keep liveness information accurate.
609 if ((uint)_idx+1 == compile->unique()) {
610 compile->set_unique(compile->unique()-1);
611 } else {
612 compile->record_dead_node(_idx);
613 }
614 // Clear debug info:
615 Node_Notes* nn = compile->node_notes_at(_idx);
616 if (nn != nullptr) nn->clear();
617 // Walk the input array, freeing the corresponding output edges
618 _cnt = _max; // forget req/prec distinction
619 uint i;
620 for( i = 0; i < _max; i++ ) {
621 set_req(i, nullptr);
622 //assert(def->out(def->outcnt()-1) == (Node *)this,"bad def-use hacking in reclaim");
623 }
624 assert(outcnt() == 0, "deleting a node must not leave a dangling use");
625
626 if (is_macro()) {
627 compile->remove_macro_node(this);
628 }
629 if (is_expensive()) {
630 compile->remove_expensive_node(this);
631 }
632 if (is_OpaqueTemplateAssertionPredicate()) {
633 compile->remove_template_assertion_predicate_opaque(as_OpaqueTemplateAssertionPredicate());
634 }
635 if (is_ParsePredicate()) {
636 compile->remove_parse_predicate(as_ParsePredicate());
637 }
638 if (for_post_loop_opts_igvn()) {
639 compile->remove_from_post_loop_opts_igvn(this);
640 }
641 if (is_InlineType()) {
642 compile->remove_inline_type(this);
643 }
644 if (for_merge_stores_igvn()) {
645 compile->remove_from_merge_stores_igvn(this);
646 }
647
648 if (is_SafePoint()) {
649 as_SafePoint()->delete_replaced_nodes();
650
651 if (is_CallStaticJava()) {
652 compile->remove_unstable_if_trap(as_CallStaticJava(), false);
653 }
654 }
655 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
656 bs->unregister_potential_barrier_node(this);
657
658 // See if the input array was allocated just prior to the object
659 int edge_size = _max*sizeof(void*);
660 int out_edge_size = _outmax*sizeof(void*);
661 char *in_array = ((char*)_in);
662 char *edge_end = in_array + edge_size;
663 char *out_array = (char*)(_out == NO_OUT_ARRAY? nullptr: _out);
664 int node_size = size_of();
665
666 #ifdef ASSERT
667 // We will not actually delete the storage, but we'll make the node unusable.
668 compile->remove_modified_node(this);
669 *(address*)this = badAddress; // smash the C++ vtbl, probably
670 _in = _out = (Node**) badAddress;
671 _max = _cnt = _outmax = _outcnt = 0;
672 #endif
673
674 // Free the output edge array
675 if (out_edge_size > 0) {
676 compile->node_arena()->Afree(out_array, out_edge_size);
677 }
678
679 // Free the input edge array and the node itself
680 if( edge_end == (char*)this ) {
681 // It was; free the input array and object all in one hit
682 #ifndef ASSERT
683 compile->node_arena()->Afree(in_array, edge_size+node_size);
684 #endif
685 } else {
686 // Free just the input array
687 compile->node_arena()->Afree(in_array, edge_size);
688
689 // Free just the object
690 #ifndef ASSERT
691 compile->node_arena()->Afree(this, node_size);
692 #endif
693 }
694 }
695
696 // Resize input or output array to grow it to the next larger power-of-2 bigger
697 // than len.
698 void Node::resize_array(Node**& array, node_idx_t& max_size, uint len, bool needs_clearing) {
699 Arena* arena = Compile::current()->node_arena();
700 uint new_max = max_size;
701 if (new_max == 0) {
702 max_size = 4;
703 array = (Node**)arena->Amalloc(4 * sizeof(Node*));
704 if (needs_clearing) {
705 array[0] = nullptr;
706 array[1] = nullptr;
707 array[2] = nullptr;
708 array[3] = nullptr;
709 }
710 return;
711 }
712 new_max = next_power_of_2(len);
713 assert(needs_clearing || (array != nullptr && array != NO_OUT_ARRAY), "out must have sensible value");
714 array = (Node**)arena->Arealloc(array, max_size * sizeof(Node*), new_max * sizeof(Node*));
715 if (needs_clearing) {
716 Copy::zero_to_bytes(&array[max_size], (new_max - max_size) * sizeof(Node*)); // null all new space
717 }
718 max_size = new_max; // Record new max length
719 // This assertion makes sure that Node::_max is wide enough to
720 // represent the numerical value of new_max.
721 assert(max_size > len, "int width of _max or _outmax is too small");
722 }
723
724 //------------------------------grow-------------------------------------------
725 // Grow the input array, making space for more edges
726 void Node::grow(uint len) {
727 resize_array(_in, _max, len, true);
728 }
729
730 //-----------------------------out_grow----------------------------------------
731 // Grow the input array, making space for more edges
732 void Node::out_grow(uint len) {
733 assert(!is_top(), "cannot grow a top node's out array");
734 resize_array(_out, _outmax, len, false);
735 }
736
737 #ifdef ASSERT
738 //------------------------------is_dead----------------------------------------
739 bool Node::is_dead() const {
740 // Mach and pinch point nodes may look like dead.
741 if( is_top() || is_Mach() || (Opcode() == Op_Node && _outcnt > 0) )
742 return false;
743 for( uint i = 0; i < _max; i++ )
744 if( _in[i] != nullptr )
745 return false;
746 return true;
747 }
748
749 bool Node::is_not_dead(const Node* n) {
750 return n == nullptr || !PhaseIterGVN::is_verify_def_use() || !(n->is_dead());
751 }
752
753 bool Node::is_reachable_from_root() const {
754 ResourceMark rm;
755 Unique_Node_List wq;
756 wq.push((Node*)this);
757 RootNode* root = Compile::current()->root();
758 for (uint i = 0; i < wq.size(); i++) {
759 Node* m = wq.at(i);
760 if (m == root) {
761 return true;
762 }
763 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) {
764 Node* u = m->fast_out(j);
765 wq.push(u);
766 }
767 }
768 return false;
769 }
770 #endif
771
772 //------------------------------is_unreachable---------------------------------
773 bool Node::is_unreachable(PhaseIterGVN &igvn) const {
774 assert(!is_Mach(), "doesn't work with MachNodes");
775 return outcnt() == 0 || igvn.type(this) == Type::TOP || (in(0) != nullptr && in(0)->is_top());
776 }
777
778 //------------------------------add_req----------------------------------------
779 // Add a new required input at the end
780 void Node::add_req( Node *n ) {
781 assert( is_not_dead(n), "can not use dead node");
782
783 // Look to see if I can move precedence down one without reallocating
784 if( (_cnt >= _max) || (in(_max-1) != nullptr) )
785 grow( _max+1 );
786
787 // Find a precedence edge to move
788 if( in(_cnt) != nullptr ) { // Next precedence edge is busy?
789 uint i;
790 for( i=_cnt; i<_max; i++ )
791 if( in(i) == nullptr ) // Find the null at end of prec edge list
792 break; // There must be one, since we grew the array
793 _in[i] = in(_cnt); // Move prec over, making space for req edge
794 }
795 _in[_cnt++] = n; // Stuff over old prec edge
796 if (n != nullptr) n->add_out((Node *)this);
797 Compile::current()->record_modified_node(this);
798 }
799
800 //---------------------------add_req_batch-------------------------------------
801 // Add a new required input at the end
802 void Node::add_req_batch( Node *n, uint m ) {
803 assert( is_not_dead(n), "can not use dead node");
804 // check various edge cases
805 if ((int)m <= 1) {
806 assert((int)m >= 0, "oob");
807 if (m != 0) add_req(n);
808 return;
809 }
810
811 // Look to see if I can move precedence down one without reallocating
812 if( (_cnt+m) > _max || _in[_max-m] )
813 grow( _max+m );
814
815 // Find a precedence edge to move
816 if( _in[_cnt] != nullptr ) { // Next precedence edge is busy?
817 uint i;
818 for( i=_cnt; i<_max; i++ )
819 if( _in[i] == nullptr ) // Find the null at end of prec edge list
820 break; // There must be one, since we grew the array
821 // Slide all the precs over by m positions (assume #prec << m).
822 Copy::conjoint_words_to_higher((HeapWord*)&_in[_cnt], (HeapWord*)&_in[_cnt+m], ((i-_cnt)*sizeof(Node*)));
823 }
824
825 // Stuff over the old prec edges
826 for(uint i=0; i<m; i++ ) {
827 _in[_cnt++] = n;
828 }
829
830 // Insert multiple out edges on the node.
831 if (n != nullptr && !n->is_top()) {
832 for(uint i=0; i<m; i++ ) {
833 n->add_out((Node *)this);
834 }
835 }
836 Compile::current()->record_modified_node(this);
837 }
838
839 //------------------------------del_req----------------------------------------
840 // Delete the required edge and compact the edge array
841 void Node::del_req( uint idx ) {
842 assert( idx < _cnt, "oob");
843 assert( !VerifyHashTableKeys || _hash_lock == 0,
844 "remove node from hash table before modifying it");
845 // First remove corresponding def-use edge
846 Node *n = in(idx);
847 if (n != nullptr) n->del_out((Node *)this);
848 _in[idx] = in(--_cnt); // Compact the array
849 // Avoid spec violation: Gap in prec edges.
850 close_prec_gap_at(_cnt);
851 Compile::current()->record_modified_node(this);
852 }
853
854 //------------------------------del_req_ordered--------------------------------
855 // Delete the required edge and compact the edge array with preserved order
856 void Node::del_req_ordered( uint idx ) {
857 assert( idx < _cnt, "oob");
858 assert( !VerifyHashTableKeys || _hash_lock == 0,
859 "remove node from hash table before modifying it");
860 // First remove corresponding def-use edge
861 Node *n = in(idx);
862 if (n != nullptr) n->del_out((Node *)this);
863 if (idx < --_cnt) { // Not last edge ?
864 Copy::conjoint_words_to_lower((HeapWord*)&_in[idx+1], (HeapWord*)&_in[idx], ((_cnt-idx)*sizeof(Node*)));
865 }
866 // Avoid spec violation: Gap in prec edges.
867 close_prec_gap_at(_cnt);
868 Compile::current()->record_modified_node(this);
869 }
870
871 //------------------------------ins_req----------------------------------------
872 // Insert a new required input at the end
873 void Node::ins_req( uint idx, Node *n ) {
874 assert( is_not_dead(n), "can not use dead node");
875 add_req(nullptr); // Make space
876 assert( idx < _max, "Must have allocated enough space");
877 // Slide over
878 if(_cnt-idx-1 > 0) {
879 Copy::conjoint_words_to_higher((HeapWord*)&_in[idx], (HeapWord*)&_in[idx+1], ((_cnt-idx-1)*sizeof(Node*)));
880 }
881 _in[idx] = n; // Stuff over old required edge
882 if (n != nullptr) n->add_out((Node *)this); // Add reciprocal def-use edge
883 Compile::current()->record_modified_node(this);
884 }
885
886 //-----------------------------find_edge---------------------------------------
887 int Node::find_edge(Node* n) {
888 for (uint i = 0; i < len(); i++) {
889 if (_in[i] == n) return i;
890 }
891 return -1;
892 }
893
894 //----------------------------replace_edge-------------------------------------
895 int Node::replace_edge(Node* old, Node* neww, PhaseGVN* gvn) {
896 if (old == neww) return 0; // nothing to do
897 uint nrep = 0;
898 for (uint i = 0; i < len(); i++) {
899 if (in(i) == old) {
900 if (i < req()) {
901 if (gvn != nullptr) {
902 set_req_X(i, neww, gvn);
903 } else {
904 set_req(i, neww);
905 }
906 } else {
907 assert(gvn == nullptr || gvn->is_IterGVN() == nullptr, "no support for igvn here");
908 assert(find_prec_edge(neww) == -1, "spec violation: duplicated prec edge (node %d -> %d)", _idx, neww->_idx);
909 set_prec(i, neww);
910 }
911 nrep++;
912 }
913 }
914 return nrep;
915 }
916
917 /**
918 * Replace input edges in the range pointing to 'old' node.
919 */
920 int Node::replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn) {
921 if (old == neww) return 0; // nothing to do
922 uint nrep = 0;
923 for (int i = start; i < end; i++) {
924 if (in(i) == old) {
925 set_req_X(i, neww, gvn);
926 nrep++;
927 }
928 }
929 return nrep;
930 }
931
932 //-------------------------disconnect_inputs-----------------------------------
933 // null out all inputs to eliminate incoming Def-Use edges.
934 void Node::disconnect_inputs(Compile* C) {
935 // the layout of Node::_in
936 // r: a required input, null is allowed
937 // p: a precedence, null values are all at the end
938 // -----------------------------------
939 // |r|...|r|p|...|p|null|...|null|
940 // | |
941 // req() len()
942 // -----------------------------------
943 for (uint i = 0; i < req(); ++i) {
944 if (in(i) != nullptr) {
945 set_req(i, nullptr);
946 }
947 }
948
949 // Remove precedence edges if any exist
950 // Note: Safepoints may have precedence edges, even during parsing
951 for (uint i = len(); i > req(); ) {
952 rm_prec(--i); // no-op if _in[i] is null
953 }
954
955 #ifdef ASSERT
956 // sanity check
957 for (uint i = 0; i < len(); ++i) {
958 assert(_in[i] == nullptr, "disconnect_inputs() failed!");
959 }
960 #endif
961
962 // Node::destruct requires all out edges be deleted first
963 // DEBUG_ONLY(destruct();) // no reuse benefit expected
964 C->record_dead_node(_idx);
965 }
966
967 //-----------------------------uncast---------------------------------------
968 // %%% Temporary, until we sort out CheckCastPP vs. CastPP.
969 // Strip away casting. (It is depth-limited.)
970 // Optionally, keep casts with dependencies.
971 Node* Node::uncast(bool keep_deps) const {
972 // Should be inline:
973 //return is_ConstraintCast() ? uncast_helper(this) : (Node*) this;
974 if (is_ConstraintCast()) {
975 return uncast_helper(this, keep_deps);
976 } else {
977 return (Node*) this;
978 }
979 }
980
981 // Find out of current node that matches opcode.
982 Node* Node::find_out_with(int opcode) {
983 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
984 Node* use = fast_out(i);
985 if (use->Opcode() == opcode) {
986 return use;
987 }
988 }
989 return nullptr;
990 }
991
992 // Return true if the current node has an out that matches opcode.
993 bool Node::has_out_with(int opcode) {
994 return (find_out_with(opcode) != nullptr);
995 }
996
997 // Return true if the current node has an out that matches any of the opcodes.
998 bool Node::has_out_with(int opcode1, int opcode2, int opcode3, int opcode4) {
999 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
1000 int opcode = fast_out(i)->Opcode();
1001 if (opcode == opcode1 || opcode == opcode2 || opcode == opcode3 || opcode == opcode4) {
1002 return true;
1003 }
1004 }
1005 return false;
1006 }
1007
1008
1009 //---------------------------uncast_helper-------------------------------------
1010 Node* Node::uncast_helper(const Node* p, bool keep_deps) {
1011 #ifdef ASSERT
1012 // If we end up traversing more nodes than we actually have,
1013 // it is definitely an infinite loop.
1014 uint max_depth = Compile::current()->unique();
1015 uint depth_count = 0;
1016 const Node* orig_p = p;
1017 #endif
1018
1019 while (true) {
1020 #ifdef ASSERT
1021 if (depth_count++ >= max_depth) {
1022 orig_p->dump(4);
1023 if (p != orig_p) {
1024 p->dump(1);
1025 }
1026 fatal("infinite loop in Node::uncast_helper");
1027 }
1028 #endif
1029 if (p == nullptr || p->req() != 2) {
1030 break;
1031 } else if (p->is_ConstraintCast()) {
1032 if (keep_deps && p->as_ConstraintCast()->carry_dependency()) {
1033 break; // stop at casts with dependencies
1034 }
1035 p = p->in(1);
1036 } else {
1037 break;
1038 }
1039 }
1040 return (Node*) p;
1041 }
1042
1043 //------------------------------add_prec---------------------------------------
1044 // Add a new precedence input. Precedence inputs are unordered, with
1045 // duplicates removed and nulls packed down at the end.
1046 void Node::add_prec( Node *n ) {
1047 assert( is_not_dead(n), "can not use dead node");
1048
1049 // Check for null at end
1050 if( _cnt >= _max || in(_max-1) )
1051 grow( _max+1 );
1052
1053 // Find a precedence edge to move
1054 uint i = _cnt;
1055 while( in(i) != nullptr ) {
1056 if (in(i) == n) return; // Avoid spec violation: duplicated prec edge.
1057 i++;
1058 }
1059 _in[i] = n; // Stuff prec edge over null
1060 if ( n != nullptr) n->add_out((Node *)this); // Add mirror edge
1061
1062 #ifdef ASSERT
1063 while ((++i)<_max) { assert(_in[i] == nullptr, "spec violation: Gap in prec edges (node %d)", _idx); }
1064 #endif
1065 Compile::current()->record_modified_node(this);
1066 }
1067
1068 //------------------------------rm_prec----------------------------------------
1069 // Remove a precedence input. Precedence inputs are unordered, with
1070 // duplicates removed and nulls packed down at the end.
1071 void Node::rm_prec( uint j ) {
1072 assert(j < _max, "oob: i=%d, _max=%d", j, _max);
1073 assert(j >= _cnt, "not a precedence edge");
1074 if (_in[j] == nullptr) return; // Avoid spec violation: Gap in prec edges.
1075 _in[j]->del_out((Node *)this);
1076 close_prec_gap_at(j);
1077 Compile::current()->record_modified_node(this);
1078 }
1079
1080 //------------------------------size_of----------------------------------------
1081 uint Node::size_of() const { return sizeof(*this); }
1082
1083 //------------------------------ideal_reg--------------------------------------
1084 uint Node::ideal_reg() const { return 0; }
1085
1086 //------------------------------jvms-------------------------------------------
1087 JVMState* Node::jvms() const { return nullptr; }
1088
1089 #ifdef ASSERT
1090 //------------------------------jvms-------------------------------------------
1091 bool Node::verify_jvms(const JVMState* using_jvms) const {
1092 for (JVMState* jvms = this->jvms(); jvms != nullptr; jvms = jvms->caller()) {
1093 if (jvms == using_jvms) return true;
1094 }
1095 return false;
1096 }
1097
1098 //------------------------------init_NodeProperty------------------------------
1099 void Node::init_NodeProperty() {
1100 assert(_max_classes <= max_juint, "too many NodeProperty classes");
1101 assert(max_flags() <= max_juint, "too many NodeProperty flags");
1102 }
1103
1104 //-----------------------------max_flags---------------------------------------
1105 juint Node::max_flags() {
1106 return (PD::_last_flag << 1) - 1; // allow flags combination
1107 }
1108 #endif
1109
1110 //------------------------------format-----------------------------------------
1111 // Print as assembly
1112 void Node::format( PhaseRegAlloc *, outputStream *st ) const {}
1113 //------------------------------emit-------------------------------------------
1114 // Emit bytes using C2_MacroAssembler
1115 void Node::emit(C2_MacroAssembler *masm, PhaseRegAlloc *ra_) const {}
1116 //------------------------------size-------------------------------------------
1117 // Size of instruction in bytes
1118 uint Node::size(PhaseRegAlloc *ra_) const { return 0; }
1119
1120 //------------------------------CFG Construction-------------------------------
1121 // Nodes that end basic blocks, e.g. IfTrue/IfFalse, JumpProjNode, Root,
1122 // Goto and Return.
1123 const Node *Node::is_block_proj() const { return nullptr; }
1124
1125 // Minimum guaranteed type
1126 const Type *Node::bottom_type() const { return Type::BOTTOM; }
1127
1128
1129 //------------------------------raise_bottom_type------------------------------
1130 // Get the worst-case Type output for this Node.
1131 void Node::raise_bottom_type(const Type* new_type) {
1132 if (is_Type()) {
1133 TypeNode *n = this->as_Type();
1134 if (VerifyAliases) {
1135 assert(new_type->higher_equal_speculative(n->type()), "new type must refine old type");
1136 }
1137 n->set_type(new_type);
1138 } else if (is_Load()) {
1139 LoadNode *n = this->as_Load();
1140 if (VerifyAliases) {
1141 assert(new_type->higher_equal_speculative(n->type()), "new type must refine old type");
1142 }
1143 n->set_type(new_type);
1144 }
1145 }
1146
1147 //------------------------------Identity---------------------------------------
1148 // Return a node that the given node is equivalent to.
1149 Node* Node::Identity(PhaseGVN* phase) {
1150 return this; // Default to no identities
1151 }
1152
1153 //------------------------------Value------------------------------------------
1154 // Compute a new Type for a node using the Type of the inputs.
1155 const Type* Node::Value(PhaseGVN* phase) const {
1156 return bottom_type(); // Default to worst-case Type
1157 }
1158
1159 //------------------------------Ideal------------------------------------------
1160 //
1161 // 'Idealize' the graph rooted at this Node.
1162 //
1163 // In order to be efficient and flexible there are some subtle invariants
1164 // these Ideal calls need to hold. Some of the flag bits for '-XX:VerifyIterativeGVN'
1165 // can help with validating these invariants, although they are too slow to have on by default:
1166 // - '-XX:VerifyIterativeGVN=1' checks the def-use info
1167 // - '-XX:VerifyIterativeGVN=100000' checks the return value
1168 // If you are hacking an Ideal call, be sure to use these.
1169 //
1170 // The Ideal call almost arbitrarily reshape the graph rooted at the 'this'
1171 // pointer. If ANY change is made, it must return the root of the reshaped
1172 // graph - even if the root is the same Node. Example: swapping the inputs
1173 // to an AddINode gives the same answer and same root, but you still have to
1174 // return the 'this' pointer instead of null. If the node was already dead
1175 // before the Ideal call, this rule does not apply, and it is fine to return
1176 // nullptr even if modifications were made.
1177 //
1178 // You cannot return an OLD Node, except for the 'this' pointer. Use the
1179 // Identity call to return an old Node; basically if Identity can find
1180 // another Node have the Ideal call make no change and return null.
1181 // Example: AddINode::Ideal must check for add of zero; in this case it
1182 // returns null instead of doing any graph reshaping.
1183 //
1184 // You cannot modify any old Nodes except for the 'this' pointer. Due to
1185 // sharing there may be other users of the old Nodes relying on their current
1186 // semantics. Modifying them will break the other users.
1187 // Example: when reshape "(X+3)+4" into "X+7" you must leave the Node for
1188 // "X+3" unchanged in case it is shared.
1189 //
1190 // If you modify the 'this' pointer's inputs, you should use
1191 // 'set_req'. If you are making a new Node (either as the new root or
1192 // some new internal piece) you may use 'init_req' to set the initial
1193 // value. You can make a new Node with either 'new' or 'clone'. In
1194 // either case, def-use info is correctly maintained.
1195 //
1196 // Example: reshape "(X+3)+4" into "X+7":
1197 // set_req(1, in(1)->in(1));
1198 // set_req(2, phase->intcon(7));
1199 // return this;
1200 // Example: reshape "X*4" into "X<<2"
1201 // return new LShiftINode(in(1), phase->intcon(2));
1202 //
1203 // You must call 'phase->transform(X)' on any new Nodes X you make, except
1204 // for the returned root node. Example: reshape "X*31" with "(X<<5)-X".
1205 // Node *shift=phase->transform(new LShiftINode(in(1),phase->intcon(5)));
1206 // return new AddINode(shift, in(1));
1207 //
1208 // When making a Node for a constant use 'phase->makecon' or 'phase->intcon'.
1209 // These forms are faster than 'phase->transform(new ConNode())' and Do
1210 // The Right Thing with def-use info.
1211 //
1212 // You cannot bury the 'this' Node inside of a graph reshape. If the reshaped
1213 // graph uses the 'this' Node it must be the root. If you want a Node with
1214 // the same Opcode as the 'this' pointer use 'clone'.
1215 //
1216 Node *Node::Ideal(PhaseGVN *phase, bool can_reshape) {
1217 return nullptr; // Default to being Ideal already
1218 }
1219
1220 // Some nodes have specific Ideal subgraph transformations only if they are
1221 // unique users of specific nodes. Such nodes should be put on IGVN worklist
1222 // for the transformations to happen.
1223 bool Node::has_special_unique_user() const {
1224 assert(outcnt() == 1, "match only for unique out");
1225 Node* n = unique_out();
1226 int op = Opcode();
1227 if (this->is_Store()) {
1228 // Condition for back-to-back stores folding.
1229 return n->Opcode() == op && n->in(MemNode::Memory) == this;
1230 } else if ((this->is_Load() || this->is_DecodeN() || this->is_Phi() || this->is_Con()) && n->Opcode() == Op_MemBarAcquire) {
1231 // Condition for removing an unused LoadNode or DecodeNNode from the MemBarAcquire precedence input
1232 return true;
1233 } else if (this->is_Load() && n->is_Move()) {
1234 // Condition for MoveX2Y (LoadX mem) => LoadY mem
1235 return true;
1236 } else if (op == Op_AddL) {
1237 // Condition for convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
1238 return n->Opcode() == Op_ConvL2I && n->in(1) == this;
1239 } else if (op == Op_SubI || op == Op_SubL) {
1240 // Condition for subI(x,subI(y,z)) ==> subI(addI(x,z),y)
1241 return n->Opcode() == op && n->in(2) == this;
1242 } else if (is_If() && (n->is_IfFalse() || n->is_IfTrue())) {
1243 // See IfProjNode::Identity()
1244 return true;
1245 } else if ((is_IfFalse() || is_IfTrue()) && n->is_If()) {
1246 // See IfNode::fold_compares
1247 return true;
1248 } else if (n->Opcode() == Op_XorV || n->Opcode() == Op_XorVMask) {
1249 // Condition for XorVMask(VectorMaskCmp(x,y,cond), MaskAll(true)) ==> VectorMaskCmp(x,y,ncond)
1250 return true;
1251 } else {
1252 return false;
1253 }
1254 };
1255
1256 //--------------------------find_exact_control---------------------------------
1257 // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1258 Node* Node::find_exact_control(Node* ctrl) {
1259 if (ctrl == nullptr && this->is_Region())
1260 ctrl = this->as_Region()->is_copy();
1261
1262 if (ctrl != nullptr && ctrl->is_CatchProj()) {
1263 if (ctrl->as_CatchProj()->_con == CatchProjNode::fall_through_index)
1264 ctrl = ctrl->in(0);
1265 if (ctrl != nullptr && !ctrl->is_top())
1266 ctrl = ctrl->in(0);
1267 }
1268
1269 if (ctrl != nullptr && ctrl->is_Proj())
1270 ctrl = ctrl->in(0);
1271
1272 return ctrl;
1273 }
1274
1275 //--------------------------dominates------------------------------------------
1276 // Helper function for MemNode::all_controls_dominate().
1277 // Check if 'this' control node dominates or equal to 'sub' control node.
1278 // We already know that if any path back to Root or Start reaches 'this',
1279 // then all paths so, so this is a simple search for one example,
1280 // not an exhaustive search for a counterexample.
1281 Node::DomResult Node::dominates(Node* sub, Node_List &nlist) {
1282 assert(this->is_CFG(), "expecting control");
1283 assert(sub != nullptr && sub->is_CFG(), "expecting control");
1284
1285 // detect dead cycle without regions
1286 int iterations_without_region_limit = DominatorSearchLimit;
1287
1288 Node* orig_sub = sub;
1289 Node* dom = this;
1290 bool met_dom = false;
1291 nlist.clear();
1292
1293 // Walk 'sub' backward up the chain to 'dom', watching for regions.
1294 // After seeing 'dom', continue up to Root or Start.
1295 // If we hit a region (backward split point), it may be a loop head.
1296 // Keep going through one of the region's inputs. If we reach the
1297 // same region again, go through a different input. Eventually we
1298 // will either exit through the loop head, or give up.
1299 // (If we get confused, break out and return a conservative 'false'.)
1300 while (sub != nullptr) {
1301 if (sub->is_top()) {
1302 // Conservative answer for dead code.
1303 return DomResult::EncounteredDeadCode;
1304 }
1305 if (sub == dom) {
1306 if (nlist.size() == 0) {
1307 // No Region nodes except loops were visited before and the EntryControl
1308 // path was taken for loops: it did not walk in a cycle.
1309 return DomResult::Dominate;
1310 } else if (met_dom) {
1311 break; // already met before: walk in a cycle
1312 } else {
1313 // Region nodes were visited. Continue walk up to Start or Root
1314 // to make sure that it did not walk in a cycle.
1315 met_dom = true; // first time meet
1316 iterations_without_region_limit = DominatorSearchLimit; // Reset
1317 }
1318 }
1319 if (sub->is_Start() || sub->is_Root()) {
1320 // Success if we met 'dom' along a path to Start or Root.
1321 // We assume there are no alternative paths that avoid 'dom'.
1322 // (This assumption is up to the caller to ensure!)
1323 return met_dom ? DomResult::Dominate : DomResult::NotDominate;
1324 }
1325 Node* up = sub->in(0);
1326 // Normalize simple pass-through regions and projections:
1327 up = sub->find_exact_control(up);
1328 // If sub == up, we found a self-loop. Try to push past it.
1329 if (sub == up && sub->is_Loop()) {
1330 // Take loop entry path on the way up to 'dom'.
1331 up = sub->in(1); // in(LoopNode::EntryControl);
1332 } else if (sub == up && sub->is_Region() && sub->req() == 2) {
1333 // Take in(1) path on the way up to 'dom' for regions with only one input
1334 up = sub->in(1);
1335 } else if (sub == up && sub->is_Region()) {
1336 // Try both paths for Regions with 2 input paths (it may be a loop head).
1337 // It could give conservative 'false' answer without information
1338 // which region's input is the entry path.
1339 iterations_without_region_limit = DominatorSearchLimit; // Reset
1340
1341 bool region_was_visited_before = false;
1342 // Was this Region node visited before?
1343 // If so, we have reached it because we accidentally took a
1344 // loop-back edge from 'sub' back into the body of the loop,
1345 // and worked our way up again to the loop header 'sub'.
1346 // So, take the first unexplored path on the way up to 'dom'.
1347 for (int j = nlist.size() - 1; j >= 0; j--) {
1348 intptr_t ni = (intptr_t)nlist.at(j);
1349 Node* visited = (Node*)(ni & ~1);
1350 bool visited_twice_already = ((ni & 1) != 0);
1351 if (visited == sub) {
1352 if (visited_twice_already) {
1353 // Visited 2 paths, but still stuck in loop body. Give up.
1354 return DomResult::NotDominate;
1355 }
1356 // The Region node was visited before only once.
1357 // (We will repush with the low bit set, below.)
1358 nlist.remove(j);
1359 // We will find a new edge and re-insert.
1360 region_was_visited_before = true;
1361 break;
1362 }
1363 }
1364
1365 // Find an incoming edge which has not been seen yet; walk through it.
1366 assert(up == sub, "");
1367 uint skip = region_was_visited_before ? 1 : 0;
1368 for (uint i = 1; i < sub->req(); i++) {
1369 Node* in = sub->in(i);
1370 if (in != nullptr && !in->is_top() && in != sub) {
1371 if (skip == 0) {
1372 up = in;
1373 break;
1374 }
1375 --skip; // skip this nontrivial input
1376 }
1377 }
1378
1379 // Set 0 bit to indicate that both paths were taken.
1380 nlist.push((Node*)((intptr_t)sub + (region_was_visited_before ? 1 : 0)));
1381 }
1382
1383 if (up == sub) {
1384 break; // some kind of tight cycle
1385 }
1386 if (up == orig_sub && met_dom) {
1387 // returned back after visiting 'dom'
1388 break; // some kind of cycle
1389 }
1390 if (--iterations_without_region_limit < 0) {
1391 break; // dead cycle
1392 }
1393 sub = up;
1394 }
1395
1396 // Did not meet Root or Start node in pred. chain.
1397 return DomResult::NotDominate;
1398 }
1399
1400 //------------------------------remove_dead_region-----------------------------
1401 // This control node is dead. Follow the subgraph below it making everything
1402 // using it dead as well. This will happen normally via the usual IterGVN
1403 // worklist but this call is more efficient. Do not update use-def info
1404 // inside the dead region, just at the borders.
1405 static void kill_dead_code( Node *dead, PhaseIterGVN *igvn ) {
1406 // Con's are a popular node to re-hit in the hash table again.
1407 if( dead->is_Con() ) return;
1408
1409 ResourceMark rm;
1410 Node_List nstack;
1411 VectorSet dead_set; // notify uses only once
1412
1413 Node *top = igvn->C->top();
1414 nstack.push(dead);
1415 bool has_irreducible_loop = igvn->C->has_irreducible_loop();
1416
1417 while (nstack.size() > 0) {
1418 dead = nstack.pop();
1419 if (!dead_set.test_set(dead->_idx)) {
1420 // If dead has any live uses, those are now still attached. Notify them before we lose them.
1421 igvn->add_users_to_worklist(dead);
1422 }
1423 if (dead->Opcode() == Op_SafePoint) {
1424 dead->as_SafePoint()->disconnect_from_root(igvn);
1425 }
1426 if (dead->outcnt() > 0) {
1427 // Keep dead node on stack until all uses are processed.
1428 nstack.push(dead);
1429 // For all Users of the Dead... ;-)
1430 for (DUIterator_Last kmin, k = dead->last_outs(kmin); k >= kmin; ) {
1431 Node* use = dead->last_out(k);
1432 igvn->hash_delete(use); // Yank from hash table prior to mod
1433 if (use->in(0) == dead) { // Found another dead node
1434 assert (!use->is_Con(), "Control for Con node should be Root node.");
1435 use->set_req(0, top); // Cut dead edge to prevent processing
1436 nstack.push(use); // the dead node again.
1437 } else if (!has_irreducible_loop && // Backedge could be alive in irreducible loop
1438 use->is_Loop() && !use->is_Root() && // Don't kill Root (RootNode extends LoopNode)
1439 use->in(LoopNode::EntryControl) == dead) { // Dead loop if its entry is dead
1440 use->set_req(LoopNode::EntryControl, top); // Cut dead edge to prevent processing
1441 use->set_req(0, top); // Cut self edge
1442 nstack.push(use);
1443 } else { // Else found a not-dead user
1444 // Dead if all inputs are top or null
1445 bool dead_use = !use->is_Root(); // Keep empty graph alive
1446 for (uint j = 1; j < use->req(); j++) {
1447 Node* in = use->in(j);
1448 if (in == dead) { // Turn all dead inputs into TOP
1449 use->set_req(j, top);
1450 } else if (in != nullptr && !in->is_top()) {
1451 dead_use = false;
1452 }
1453 }
1454 if (dead_use) {
1455 if (use->is_Region()) {
1456 use->set_req(0, top); // Cut self edge
1457 }
1458 nstack.push(use);
1459 } else {
1460 igvn->_worklist.push(use);
1461 }
1462 }
1463 // Refresh the iterator, since any number of kills might have happened.
1464 k = dead->last_outs(kmin);
1465 }
1466 } else { // (dead->outcnt() == 0)
1467 // Done with outputs.
1468 igvn->hash_delete(dead);
1469 igvn->_worklist.remove(dead);
1470 igvn->set_type(dead, Type::TOP);
1471 // Kill all inputs to the dead guy
1472 for (uint i=0; i < dead->req(); i++) {
1473 Node *n = dead->in(i); // Get input to dead guy
1474 if (n != nullptr && !n->is_top()) { // Input is valid?
1475 dead->set_req(i, top); // Smash input away
1476 if (n->outcnt() == 0) { // Input also goes dead?
1477 if (!n->is_Con())
1478 nstack.push(n); // Clear it out as well
1479 } else if (n->outcnt() == 1 &&
1480 n->has_special_unique_user()) {
1481 igvn->add_users_to_worklist( n );
1482 } else if (n->outcnt() <= 2 && n->is_Store()) {
1483 // Push store's uses on worklist to enable folding optimization for
1484 // store/store and store/load to the same address.
1485 // The restriction (outcnt() <= 2) is the same as in set_req_X()
1486 // and remove_globally_dead_node().
1487 igvn->add_users_to_worklist( n );
1488 } else if (dead->is_data_proj_of_pure_function(n)) {
1489 igvn->_worklist.push(n);
1490 } else {
1491 BarrierSet::barrier_set()->barrier_set_c2()->enqueue_useful_gc_barrier(igvn, n);
1492 }
1493 }
1494 }
1495 igvn->C->remove_useless_node(dead);
1496 } // (dead->outcnt() == 0)
1497 } // while (nstack.size() > 0) for outputs
1498 return;
1499 }
1500
1501 //------------------------------remove_dead_region-----------------------------
1502 bool Node::remove_dead_region(PhaseGVN *phase, bool can_reshape) {
1503 Node *n = in(0);
1504 if( !n ) return false;
1505 // Lost control into this guy? I.e., it became unreachable?
1506 // Aggressively kill all unreachable code.
1507 if (can_reshape && n->is_top()) {
1508 kill_dead_code(this, phase->is_IterGVN());
1509 return false; // Node is dead.
1510 }
1511
1512 if( n->is_Region() && n->as_Region()->is_copy() ) {
1513 Node *m = n->nonnull_req();
1514 set_req(0, m);
1515 return true;
1516 }
1517 return false;
1518 }
1519
1520 //------------------------------hash-------------------------------------------
1521 // Hash function over Nodes.
1522 uint Node::hash() const {
1523 uint sum = 0;
1524 for( uint i=0; i<_cnt; i++ ) // Add in all inputs
1525 sum = (sum<<1)-(uintptr_t)in(i); // Ignore embedded nulls
1526 return (sum>>2) + _cnt + Opcode();
1527 }
1528
1529 //------------------------------cmp--------------------------------------------
1530 // Compare special parts of simple Nodes
1531 bool Node::cmp( const Node &n ) const {
1532 return true; // Must be same
1533 }
1534
1535 //------------------------------rematerialize-----------------------------------
1536 // Should we clone rather than spill this instruction?
1537 bool Node::rematerialize() const {
1538 if ( is_Mach() )
1539 return this->as_Mach()->rematerialize();
1540 else
1541 return (_flags & Flag_rematerialize) != 0;
1542 }
1543
1544 //------------------------------needs_anti_dependence_check---------------------
1545 // Nodes which use memory without consuming it, hence need antidependences.
1546 bool Node::needs_anti_dependence_check() const {
1547 if (req() < 2 || (_flags & Flag_needs_anti_dependence_check) == 0) {
1548 return false;
1549 }
1550 return in(1)->bottom_type()->has_memory();
1551 }
1552
1553 // Get an integer constant from a ConNode (or CastIINode).
1554 // Return a default value if there is no apparent constant here.
1555 const TypeInt* Node::find_int_type() const {
1556 if (this->is_Type()) {
1557 return this->as_Type()->type()->isa_int();
1558 } else if (this->is_Con()) {
1559 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1560 return this->bottom_type()->isa_int();
1561 }
1562 return nullptr;
1563 }
1564
1565 const TypeInteger* Node::find_integer_type(BasicType bt) const {
1566 if (this->is_Type()) {
1567 return this->as_Type()->type()->isa_integer(bt);
1568 } else if (this->is_Con()) {
1569 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1570 return this->bottom_type()->isa_integer(bt);
1571 }
1572 return nullptr;
1573 }
1574
1575 // Get a pointer constant from a ConstNode.
1576 // Returns the constant if it is a pointer ConstNode
1577 intptr_t Node::get_ptr() const {
1578 assert( Opcode() == Op_ConP, "" );
1579 return ((ConPNode*)this)->type()->is_ptr()->get_con();
1580 }
1581
1582 // Get a narrow oop constant from a ConNNode.
1583 intptr_t Node::get_narrowcon() const {
1584 assert( Opcode() == Op_ConN, "" );
1585 return ((ConNNode*)this)->type()->is_narrowoop()->get_con();
1586 }
1587
1588 // Get a long constant from a ConNode.
1589 // Return a default value if there is no apparent constant here.
1590 const TypeLong* Node::find_long_type() const {
1591 if (this->is_Type()) {
1592 return this->as_Type()->type()->isa_long();
1593 } else if (this->is_Con()) {
1594 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1595 return this->bottom_type()->isa_long();
1596 }
1597 return nullptr;
1598 }
1599
1600
1601 /**
1602 * Return a ptr type for nodes which should have it.
1603 */
1604 const TypePtr* Node::get_ptr_type() const {
1605 const TypePtr* tp = this->bottom_type()->make_ptr();
1606 #ifdef ASSERT
1607 if (tp == nullptr) {
1608 this->dump(1);
1609 assert((tp != nullptr), "unexpected node type");
1610 }
1611 #endif
1612 return tp;
1613 }
1614
1615 // Get a double constant from a ConstNode.
1616 // Returns the constant if it is a double ConstNode
1617 jdouble Node::getd() const {
1618 assert( Opcode() == Op_ConD, "" );
1619 return ((ConDNode*)this)->type()->is_double_constant()->getd();
1620 }
1621
1622 // Get a float constant from a ConstNode.
1623 // Returns the constant if it is a float ConstNode
1624 jfloat Node::getf() const {
1625 assert( Opcode() == Op_ConF, "" );
1626 return ((ConFNode*)this)->type()->is_float_constant()->getf();
1627 }
1628
1629 // Get a half float constant from a ConstNode.
1630 // Returns the constant if it is a float ConstNode
1631 jshort Node::geth() const {
1632 assert( Opcode() == Op_ConH, "" );
1633 return ((ConHNode*)this)->type()->is_half_float_constant()->geth();
1634 }
1635
1636 #ifndef PRODUCT
1637
1638 // Call this from debugger:
1639 Node* old_root() {
1640 Matcher* matcher = Compile::current()->matcher();
1641 if (matcher != nullptr) {
1642 Node* new_root = Compile::current()->root();
1643 Node* old_root = matcher->find_old_node(new_root);
1644 if (old_root != nullptr) {
1645 return old_root;
1646 }
1647 }
1648 tty->print("old_root: not found.\n");
1649 return nullptr;
1650 }
1651
1652 // BFS traverse all reachable nodes from start, call callback on them
1653 template <typename Callback>
1654 void visit_nodes(Node* start, Callback callback, bool traverse_output, bool only_ctrl) {
1655 Unique_Mixed_Node_List worklist;
1656 worklist.add(start);
1657 for (uint i = 0; i < worklist.size(); i++) {
1658 Node* n = worklist[i];
1659 callback(n);
1660 for (uint i = 0; i < n->len(); i++) {
1661 if (!only_ctrl || n->is_Region() || (n->Opcode() == Op_Root) || (i == TypeFunc::Control)) {
1662 // If only_ctrl is set: Add regions, the root node, or control inputs only
1663 worklist.add(n->in(i));
1664 }
1665 }
1666 if (traverse_output && !only_ctrl) {
1667 for (uint i = 0; i < n->outcnt(); i++) {
1668 worklist.add(n->raw_out(i));
1669 }
1670 }
1671 }
1672 }
1673
1674 // BFS traverse from start, return node with idx
1675 static Node* find_node_by_idx(Node* start, uint idx, bool traverse_output, bool only_ctrl) {
1676 ResourceMark rm;
1677 Node* result = nullptr;
1678 auto callback = [&] (Node* n) {
1679 if (n->_idx == idx) {
1680 if (result != nullptr) {
1681 tty->print("find_node_by_idx: " INTPTR_FORMAT " and " INTPTR_FORMAT " both have idx==%d\n",
1682 (uintptr_t)result, (uintptr_t)n, idx);
1683 }
1684 result = n;
1685 }
1686 };
1687 visit_nodes(start, callback, traverse_output, only_ctrl);
1688 return result;
1689 }
1690
1691 static int node_idx_cmp(const Node** n1, const Node** n2) {
1692 return (*n1)->_idx - (*n2)->_idx;
1693 }
1694
1695 static void find_nodes_by_name(Node* start, const char* name) {
1696 ResourceMark rm;
1697 GrowableArray<const Node*> ns;
1698 auto callback = [&] (const Node* n) {
1699 if (StringUtils::is_star_match(name, n->Name())) {
1700 ns.push(n);
1701 }
1702 };
1703 visit_nodes(start, callback, true, false);
1704 ns.sort(node_idx_cmp);
1705 for (int i = 0; i < ns.length(); i++) {
1706 ns.at(i)->dump();
1707 }
1708 }
1709
1710 static void find_nodes_by_dump(Node* start, const char* pattern) {
1711 ResourceMark rm;
1712 GrowableArray<const Node*> ns;
1713 auto callback = [&] (const Node* n) {
1714 stringStream stream;
1715 n->dump("", false, &stream);
1716 if (StringUtils::is_star_match(pattern, stream.base())) {
1717 ns.push(n);
1718 }
1719 };
1720 visit_nodes(start, callback, true, false);
1721 ns.sort(node_idx_cmp);
1722 for (int i = 0; i < ns.length(); i++) {
1723 ns.at(i)->dump();
1724 }
1725 }
1726
1727 // call from debugger: find node with name pattern in new/current graph
1728 // name can contain "*" in match pattern to match any characters
1729 // the matching is case insensitive
1730 void find_nodes_by_name(const char* name) {
1731 Node* root = Compile::current()->root();
1732 find_nodes_by_name(root, name);
1733 }
1734
1735 // call from debugger: find node with name pattern in old graph
1736 // name can contain "*" in match pattern to match any characters
1737 // the matching is case insensitive
1738 void find_old_nodes_by_name(const char* name) {
1739 Node* root = old_root();
1740 find_nodes_by_name(root, name);
1741 }
1742
1743 // call from debugger: find node with dump pattern in new/current graph
1744 // can contain "*" in match pattern to match any characters
1745 // the matching is case insensitive
1746 void find_nodes_by_dump(const char* pattern) {
1747 Node* root = Compile::current()->root();
1748 find_nodes_by_dump(root, pattern);
1749 }
1750
1751 // call from debugger: find node with name pattern in old graph
1752 // can contain "*" in match pattern to match any characters
1753 // the matching is case insensitive
1754 void find_old_nodes_by_dump(const char* pattern) {
1755 Node* root = old_root();
1756 find_nodes_by_dump(root, pattern);
1757 }
1758
1759 // Call this from debugger, search in same graph as n:
1760 Node* find_node(Node* n, const int idx) {
1761 return n->find(idx);
1762 }
1763
1764 // Call this from debugger, search in new nodes:
1765 Node* find_node(const int idx) {
1766 return Compile::current()->root()->find(idx);
1767 }
1768
1769 // Call this from debugger, search in old nodes:
1770 Node* find_old_node(const int idx) {
1771 Node* root = old_root();
1772 return (root == nullptr) ? nullptr : root->find(idx);
1773 }
1774
1775 // Call this from debugger, search in same graph as n:
1776 Node* find_ctrl(Node* n, const int idx) {
1777 return n->find_ctrl(idx);
1778 }
1779
1780 // Call this from debugger, search in new nodes:
1781 Node* find_ctrl(const int idx) {
1782 return Compile::current()->root()->find_ctrl(idx);
1783 }
1784
1785 // Call this from debugger, search in old nodes:
1786 Node* find_old_ctrl(const int idx) {
1787 Node* root = old_root();
1788 return (root == nullptr) ? nullptr : root->find_ctrl(idx);
1789 }
1790
1791 //------------------------------find_ctrl--------------------------------------
1792 // Find an ancestor to this node in the control history with given _idx
1793 Node* Node::find_ctrl(int idx) {
1794 return find(idx, true);
1795 }
1796
1797 //------------------------------find-------------------------------------------
1798 // Tries to find the node with the index |idx| starting from this node. If idx is negative,
1799 // the search also includes forward (out) edges. Returns null if not found.
1800 // If only_ctrl is set, the search will only be done on control nodes. Returns null if
1801 // not found or if the node to be found is not a control node (search will not find it).
1802 Node* Node::find(const int idx, bool only_ctrl) {
1803 ResourceMark rm;
1804 return find_node_by_idx(this, abs(idx), (idx < 0), only_ctrl);
1805 }
1806
1807 class PrintBFS {
1808 public:
1809 PrintBFS(const Node* start, const int max_distance, const Node* target, const char* options, outputStream* st, const frame* fr)
1810 : _start(start), _max_distance(max_distance), _target(target), _options(options), _output(st), _frame(fr),
1811 _dcc(this), _info_uid(cmpkey, hashkey) {}
1812
1813 void run();
1814 private:
1815 // pipeline steps
1816 bool configure();
1817 void collect();
1818 void select();
1819 void select_all();
1820 void select_all_paths();
1821 void select_shortest_path();
1822 void sort();
1823 void print();
1824
1825 // inputs
1826 const Node* _start;
1827 const int _max_distance;
1828 const Node* _target;
1829 const char* _options;
1830 outputStream* _output;
1831 const frame* _frame;
1832
1833 // options
1834 bool _traverse_inputs = false;
1835 bool _traverse_outputs = false;
1836 struct Filter {
1837 bool _control = false;
1838 bool _memory = false;
1839 bool _data = false;
1840 bool _mixed = false;
1841 bool _other = false;
1842 bool is_empty() const {
1843 return !(_control || _memory || _data || _mixed || _other);
1844 }
1845 void set_all() {
1846 _control = true;
1847 _memory = true;
1848 _data = true;
1849 _mixed = true;
1850 _other = true;
1851 }
1852 // Check if the filter accepts the node. Go by the type categories, but also all CFG nodes
1853 // are considered to have control.
1854 bool accepts(const Node* n) {
1855 const Type* t = n->bottom_type();
1856 return ( _data && t->has_category(Type::Category::Data) ) ||
1857 ( _memory && t->has_category(Type::Category::Memory) ) ||
1858 ( _mixed && t->has_category(Type::Category::Mixed) ) ||
1859 ( _control && (t->has_category(Type::Category::Control) || n->is_CFG()) ) ||
1860 ( _other && t->has_category(Type::Category::Other) );
1861 }
1862 };
1863 Filter _filter_visit;
1864 Filter _filter_boundary;
1865 bool _sort_idx = false;
1866 bool _all_paths = false;
1867 bool _use_color = false;
1868 bool _print_blocks = false;
1869 bool _print_old = false;
1870 bool _dump_only = false;
1871 bool _print_igv = false;
1872
1873 void print_options_help(bool print_examples);
1874 bool parse_options();
1875
1876 public:
1877 class DumpConfigColored : public Node::DumpConfig {
1878 public:
1879 DumpConfigColored(PrintBFS* bfs) : _bfs(bfs) {};
1880 virtual void pre_dump(outputStream* st, const Node* n);
1881 virtual void post_dump(outputStream* st);
1882 private:
1883 PrintBFS* _bfs;
1884 };
1885 private:
1886 DumpConfigColored _dcc;
1887
1888 // node info
1889 static Node* old_node(const Node* n); // mach node -> prior IR node
1890 void print_node_idx(const Node* n);
1891 void print_block_id(const Block* b);
1892 void print_node_block(const Node* n); // _pre_order, head idx, _idom, _dom_depth
1893
1894 // traversal data structures
1895 GrowableArray<const Node*> _worklist; // BFS queue
1896 void maybe_traverse(const Node* src, const Node* dst);
1897
1898 // node info annotation
1899 class Info {
1900 public:
1901 Info() : Info(nullptr, 0) {};
1902 Info(const Node* node, int distance)
1903 : _node(node), _distance_from_start(distance) {};
1904 const Node* node() const { return _node; };
1905 int distance() const { return _distance_from_start; };
1906 int distance_from_target() const { return _distance_from_target; }
1907 void set_distance_from_target(int d) { _distance_from_target = d; }
1908 GrowableArray<const Node*> edge_bwd; // pointing toward _start
1909 bool is_marked() const { return _mark; } // marked to keep during select
1910 void set_mark() { _mark = true; }
1911 private:
1912 const Node* _node;
1913 int _distance_from_start; // distance from _start
1914 int _distance_from_target = 0; // distance from _target if _all_paths
1915 bool _mark = false;
1916 };
1917 Dict _info_uid; // Node -> uid
1918 GrowableArray<Info> _info; // uid -> info
1919
1920 Info* find_info(const Node* n) {
1921 size_t uid = (size_t)_info_uid[n];
1922 if (uid == 0) {
1923 return nullptr;
1924 }
1925 return &_info.at((int)uid);
1926 }
1927
1928 void make_info(const Node* node, const int distance) {
1929 assert(find_info(node) == nullptr, "node does not yet have info");
1930 size_t uid = _info.length() + 1;
1931 _info_uid.Insert((void*)node, (void*)uid);
1932 _info.at_put_grow((int)uid, Info(node, distance));
1933 assert(find_info(node)->node() == node, "stored correct node");
1934 };
1935
1936 // filled by sort, printed by print
1937 GrowableArray<const Node*> _print_list;
1938
1939 // print header + node table
1940 void print_header() const;
1941 void print_node(const Node* n);
1942 };
1943
1944 void PrintBFS::run() {
1945 if (!configure()) {
1946 return;
1947 }
1948 collect();
1949 select();
1950 sort();
1951 print();
1952 }
1953
1954 // set up configuration for BFS and print
1955 bool PrintBFS::configure() {
1956 if (_max_distance < 0) {
1957 _output->print_cr("dump_bfs: max_distance must be non-negative!");
1958 return false;
1959 }
1960 return parse_options();
1961 }
1962
1963 // BFS traverse according to configuration, fill worklist and info
1964 void PrintBFS::collect() {
1965 maybe_traverse(_start, _start);
1966 int pos = 0;
1967 while (pos < _worklist.length()) {
1968 const Node* n = _worklist.at(pos++); // next node to traverse
1969 Info* info = find_info(n);
1970 if (!_filter_visit.accepts(n) && n != _start) {
1971 continue; // we hit boundary, do not traverse further
1972 }
1973 if (n != _start && n->is_Root()) {
1974 continue; // traversing through root node would lead to unrelated nodes
1975 }
1976 if (_traverse_inputs && _max_distance > info->distance()) {
1977 for (uint i = 0; i < n->req(); i++) {
1978 maybe_traverse(n, n->in(i));
1979 }
1980 }
1981 if (_traverse_outputs && _max_distance > info->distance()) {
1982 for (uint i = 0; i < n->outcnt(); i++) {
1983 maybe_traverse(n, n->raw_out(i));
1984 }
1985 }
1986 }
1987 }
1988
1989 // go through work list, mark those that we want to print
1990 void PrintBFS::select() {
1991 if (_target == nullptr ) {
1992 select_all();
1993 } else {
1994 if (find_info(_target) == nullptr) {
1995 _output->print_cr("Could not find target in BFS.");
1996 return;
1997 }
1998 if (_all_paths) {
1999 select_all_paths();
2000 } else {
2001 select_shortest_path();
2002 }
2003 }
2004 }
2005
2006 // take all nodes from BFS
2007 void PrintBFS::select_all() {
2008 for (int i = 0; i < _worklist.length(); i++) {
2009 const Node* n = _worklist.at(i);
2010 Info* info = find_info(n);
2011 info->set_mark();
2012 }
2013 }
2014
2015 // traverse backward from target, along edges found in BFS
2016 void PrintBFS::select_all_paths() {
2017 int pos = 0;
2018 GrowableArray<const Node*> backtrace;
2019 // start from target
2020 backtrace.push(_target);
2021 find_info(_target)->set_mark();
2022 // traverse backward
2023 while (pos < backtrace.length()) {
2024 const Node* n = backtrace.at(pos++);
2025 Info* info = find_info(n);
2026 for (int i = 0; i < info->edge_bwd.length(); i++) {
2027 // all backward edges
2028 const Node* back = info->edge_bwd.at(i);
2029 Info* back_info = find_info(back);
2030 if (!back_info->is_marked()) {
2031 // not yet found this on way back.
2032 back_info->set_distance_from_target(info->distance_from_target() + 1);
2033 if (back_info->distance_from_target() + back_info->distance() <= _max_distance) {
2034 // total distance is small enough
2035 back_info->set_mark();
2036 backtrace.push(back);
2037 }
2038 }
2039 }
2040 }
2041 }
2042
2043 void PrintBFS::select_shortest_path() {
2044 const Node* current = _target;
2045 while (true) {
2046 Info* info = find_info(current);
2047 info->set_mark();
2048 if (current == _start) {
2049 break;
2050 }
2051 // first edge -> leads us one step closer to _start
2052 current = info->edge_bwd.at(0);
2053 }
2054 }
2055
2056 // go through worklist in desired order, put the marked ones in print list
2057 void PrintBFS::sort() {
2058 if (_traverse_inputs && !_traverse_outputs) {
2059 // reverse order
2060 for (int i = _worklist.length() - 1; i >= 0; i--) {
2061 const Node* n = _worklist.at(i);
2062 Info* info = find_info(n);
2063 if (info->is_marked()) {
2064 _print_list.push(n);
2065 }
2066 }
2067 } else {
2068 // same order as worklist
2069 for (int i = 0; i < _worklist.length(); i++) {
2070 const Node* n = _worklist.at(i);
2071 Info* info = find_info(n);
2072 if (info->is_marked()) {
2073 _print_list.push(n);
2074 }
2075 }
2076 }
2077 if (_sort_idx) {
2078 _print_list.sort(node_idx_cmp);
2079 }
2080 }
2081
2082 // go through printlist and print
2083 void PrintBFS::print() {
2084 if (_print_list.length() > 0 ) {
2085 print_header();
2086 for (int i = 0; i < _print_list.length(); i++) {
2087 const Node* n = _print_list.at(i);
2088 print_node(n);
2089 }
2090 if (_print_igv) {
2091 Compile* C = Compile::current();
2092 C->init_igv();
2093 C->igv_print_graph_to_network(nullptr, _print_list, _frame);
2094 }
2095 } else {
2096 _output->print_cr("No nodes to print.");
2097 }
2098 }
2099
2100 void PrintBFS::print_options_help(bool print_examples) {
2101 _output->print_cr("Usage: node->dump_bfs(int max_distance, Node* target, char* options)");
2102 _output->print_cr("");
2103 _output->print_cr("Use cases:");
2104 _output->print_cr(" BFS traversal: no target required");
2105 _output->print_cr(" shortest path: set target");
2106 _output->print_cr(" all paths: set target and put 'A' in options");
2107 _output->print_cr(" detect loop: subcase of all paths, have start==target");
2108 _output->print_cr("");
2109 _output->print_cr("Arguments:");
2110 _output->print_cr(" this/start: staring point of BFS");
2111 _output->print_cr(" target:");
2112 _output->print_cr(" if null: simple BFS");
2113 _output->print_cr(" else: shortest path or all paths between this/start and target");
2114 _output->print_cr(" options:");
2115 _output->print_cr(" if null: same as \"cdmox@B\"");
2116 _output->print_cr(" else: use combination of following characters");
2117 _output->print_cr(" h: display this help info");
2118 _output->print_cr(" H: display this help info, with examples");
2119 _output->print_cr(" +: traverse in-edges (on if neither + nor -)");
2120 _output->print_cr(" -: traverse out-edges");
2121 _output->print_cr(" c: visit control nodes");
2122 _output->print_cr(" d: visit data nodes");
2123 _output->print_cr(" m: visit memory nodes");
2124 _output->print_cr(" o: visit other nodes");
2125 _output->print_cr(" x: visit mixed nodes");
2126 _output->print_cr(" C: boundary control nodes");
2127 _output->print_cr(" D: boundary data nodes");
2128 _output->print_cr(" M: boundary memory nodes");
2129 _output->print_cr(" O: boundary other nodes");
2130 _output->print_cr(" X: boundary mixed nodes");
2131 _output->print_cr(" #: display node category in color (not supported in all terminals)");
2132 _output->print_cr(" S: sort displayed nodes by node idx");
2133 _output->print_cr(" A: all paths (not just shortest path to target)");
2134 _output->print_cr(" @: print old nodes - before matching (if available)");
2135 _output->print_cr(" B: print scheduling blocks (if available)");
2136 _output->print_cr(" $: dump only, no header, no other columns");
2137 _output->print_cr(" !: show nodes on IGV (sent over network stream)");
2138 _output->print_cr(" (use preferably with dump_bfs(int, Node*, char*, void*, void*, void*)");
2139 _output->print_cr(" to produce a C2 stack trace along with the graph dump, see examples below)");
2140 _output->print_cr("");
2141 _output->print_cr("recursively follow edges to nodes with permitted visit types,");
2142 _output->print_cr("on the boundary additionally display nodes allowed in boundary types");
2143 _output->print_cr("Note: the categories can be overlapping. For example a mixed node");
2144 _output->print_cr(" can contain control and memory output. Some from the other");
2145 _output->print_cr(" category are also control (Halt, Return, etc).");
2146 _output->print_cr("");
2147 _output->print_cr("output columns:");
2148 _output->print_cr(" dist: BFS distance to this/start");
2149 _output->print_cr(" apd: all paths distance (d_outputart + d_target)");
2150 _output->print_cr(" block: block identifier, based on _pre_order");
2151 _output->print_cr(" head: first node in block");
2152 _output->print_cr(" idom: head node of idom block");
2153 _output->print_cr(" depth: depth of block (_dom_depth)");
2154 _output->print_cr(" old: old IR node - before matching");
2155 _output->print_cr(" dump: node->dump()");
2156 _output->print_cr("");
2157 _output->print_cr("Note: if none of the \"cmdxo\" characters are in the options string");
2158 _output->print_cr(" then we set all of them.");
2159 _output->print_cr(" This allows for short strings like \"#\" for colored input traversal");
2160 _output->print_cr(" or \"-#\" for colored output traversal.");
2161 if (print_examples) {
2162 _output->print_cr("");
2163 _output->print_cr("Examples:");
2164 _output->print_cr(" if->dump_bfs(10, 0, \"+cxo\")");
2165 _output->print_cr(" starting at some if node, traverse inputs recursively");
2166 _output->print_cr(" only along control (mixed and other can also be control)");
2167 _output->print_cr(" phi->dump_bfs(5, 0, \"-dxo\")");
2168 _output->print_cr(" starting at phi node, traverse outputs recursively");
2169 _output->print_cr(" only along data (mixed and other can also have data flow)");
2170 _output->print_cr(" find_node(385)->dump_bfs(3, 0, \"cdmox+#@B\")");
2171 _output->print_cr(" find inputs of node 385, up to 3 nodes up (+)");
2172 _output->print_cr(" traverse all nodes (cdmox), use colors (#)");
2173 _output->print_cr(" display old nodes and blocks, if they exist");
2174 _output->print_cr(" useful call to start with");
2175 _output->print_cr(" find_node(102)->dump_bfs(10, 0, \"dCDMOX-\")");
2176 _output->print_cr(" find non-data dependencies of a data node");
2177 _output->print_cr(" follow data node outputs until we find another category");
2178 _output->print_cr(" node as the boundary");
2179 _output->print_cr(" x->dump_bfs(10, y, 0)");
2180 _output->print_cr(" find shortest path from x to y, along any edge or node");
2181 _output->print_cr(" will not find a path if it is longer than 10");
2182 _output->print_cr(" useful to find how x and y are related");
2183 _output->print_cr(" find_node(741)->dump_bfs(20, find_node(746), \"c+\")");
2184 _output->print_cr(" find shortest control path between two nodes");
2185 _output->print_cr(" find_node(741)->dump_bfs(8, find_node(746), \"cdmox+A\")");
2186 _output->print_cr(" find all paths (A) between two nodes of length at most 8");
2187 _output->print_cr(" find_node(741)->dump_bfs(7, find_node(741), \"c+A\")");
2188 _output->print_cr(" find all control loops for this node");
2189 _output->print_cr(" find_node(741)->dump_bfs(7, find_node(741), \"c+A!\", $sp, $fp, $pc)");
2190 _output->print_cr(" same as above, but printing the resulting subgraph");
2191 _output->print_cr(" along with a C2 stack trace on IGV");
2192 }
2193 }
2194
2195 bool PrintBFS::parse_options() {
2196 if (_options == nullptr) {
2197 _options = "cdmox@B"; // default options
2198 }
2199 size_t len = strlen(_options);
2200 for (size_t i = 0; i < len; i++) {
2201 switch (_options[i]) {
2202 case '+':
2203 _traverse_inputs = true;
2204 break;
2205 case '-':
2206 _traverse_outputs = true;
2207 break;
2208 case 'c':
2209 _filter_visit._control = true;
2210 break;
2211 case 'm':
2212 _filter_visit._memory = true;
2213 break;
2214 case 'd':
2215 _filter_visit._data = true;
2216 break;
2217 case 'x':
2218 _filter_visit._mixed = true;
2219 break;
2220 case 'o':
2221 _filter_visit._other = true;
2222 break;
2223 case 'C':
2224 _filter_boundary._control = true;
2225 break;
2226 case 'M':
2227 _filter_boundary._memory = true;
2228 break;
2229 case 'D':
2230 _filter_boundary._data = true;
2231 break;
2232 case 'X':
2233 _filter_boundary._mixed = true;
2234 break;
2235 case 'O':
2236 _filter_boundary._other = true;
2237 break;
2238 case 'S':
2239 _sort_idx = true;
2240 break;
2241 case 'A':
2242 _all_paths = true;
2243 break;
2244 case '#':
2245 _use_color = true;
2246 break;
2247 case 'B':
2248 _print_blocks = true;
2249 break;
2250 case '@':
2251 _print_old = true;
2252 break;
2253 case '$':
2254 _dump_only = true;
2255 break;
2256 case '!':
2257 _print_igv = true;
2258 break;
2259 case 'h':
2260 print_options_help(false);
2261 return false;
2262 case 'H':
2263 print_options_help(true);
2264 return false;
2265 default:
2266 _output->print_cr("dump_bfs: Unrecognized option \'%c\'", _options[i]);
2267 _output->print_cr("for help, run: find_node(0)->dump_bfs(0,0,\"H\")");
2268 return false;
2269 }
2270 }
2271 if (!_traverse_inputs && !_traverse_outputs) {
2272 _traverse_inputs = true;
2273 }
2274 if (_filter_visit.is_empty()) {
2275 _filter_visit.set_all();
2276 }
2277 Compile* C = Compile::current();
2278 _print_old &= (C->matcher() != nullptr); // only show old if there are new
2279 _print_blocks &= (C->cfg() != nullptr); // only show blocks if available
2280 return true;
2281 }
2282
2283 void PrintBFS::DumpConfigColored::pre_dump(outputStream* st, const Node* n) {
2284 if (!_bfs->_use_color) {
2285 return;
2286 }
2287 Info* info = _bfs->find_info(n);
2288 if (info == nullptr || !info->is_marked()) {
2289 return;
2290 }
2291
2292 const Type* t = n->bottom_type();
2293 switch (t->category()) {
2294 case Type::Category::Data:
2295 st->print("\u001b[34m");
2296 break;
2297 case Type::Category::Memory:
2298 st->print("\u001b[32m");
2299 break;
2300 case Type::Category::Mixed:
2301 st->print("\u001b[35m");
2302 break;
2303 case Type::Category::Control:
2304 st->print("\u001b[31m");
2305 break;
2306 case Type::Category::Other:
2307 st->print("\u001b[33m");
2308 break;
2309 case Type::Category::Undef:
2310 n->dump();
2311 assert(false, "category undef ??");
2312 break;
2313 default:
2314 n->dump();
2315 assert(false, "not covered");
2316 break;
2317 }
2318 }
2319
2320 void PrintBFS::DumpConfigColored::post_dump(outputStream* st) {
2321 if (!_bfs->_use_color) {
2322 return;
2323 }
2324 st->print("\u001b[0m"); // white
2325 }
2326
2327 Node* PrintBFS::old_node(const Node* n) {
2328 Compile* C = Compile::current();
2329 if (C->matcher() == nullptr || !C->node_arena()->contains(n)) {
2330 return (Node*)nullptr;
2331 } else {
2332 return C->matcher()->find_old_node(n);
2333 }
2334 }
2335
2336 void PrintBFS::print_node_idx(const Node* n) {
2337 Compile* C = Compile::current();
2338 char buf[30];
2339 if (n == nullptr) {
2340 os::snprintf_checked(buf, sizeof(buf), "_"); // null
2341 } else if (C->node_arena()->contains(n)) {
2342 os::snprintf_checked(buf, sizeof(buf), "%d", n->_idx); // new node
2343 } else {
2344 os::snprintf_checked(buf, sizeof(buf), "o%d", n->_idx); // old node
2345 }
2346 _output->print("%6s", buf);
2347 }
2348
2349 void PrintBFS::print_block_id(const Block* b) {
2350 Compile* C = Compile::current();
2351 char buf[30];
2352 os::snprintf_checked(buf, sizeof(buf), "B%d", b->_pre_order);
2353 _output->print("%7s", buf);
2354 }
2355
2356 void PrintBFS::print_node_block(const Node* n) {
2357 Compile* C = Compile::current();
2358 Block* b = C->node_arena()->contains(n)
2359 ? C->cfg()->get_block_for_node(n)
2360 : nullptr; // guard against old nodes
2361 if (b == nullptr) {
2362 _output->print(" _"); // Block
2363 _output->print(" _"); // head
2364 _output->print(" _"); // idom
2365 _output->print(" _"); // depth
2366 } else {
2367 print_block_id(b);
2368 print_node_idx(b->head());
2369 if (b->_idom) {
2370 print_node_idx(b->_idom->head());
2371 } else {
2372 _output->print(" _"); // idom
2373 }
2374 _output->print("%6d ", b->_dom_depth);
2375 }
2376 }
2377
2378 // filter, and add to worklist, add info, note traversal edges
2379 void PrintBFS::maybe_traverse(const Node* src, const Node* dst) {
2380 if (dst != nullptr &&
2381 (_filter_visit.accepts(dst) ||
2382 _filter_boundary.accepts(dst) ||
2383 dst == _start)) { // correct category or start?
2384 if (find_info(dst) == nullptr) {
2385 // never visited - set up info
2386 _worklist.push(dst);
2387 int d = 0;
2388 if (dst != _start) {
2389 d = find_info(src)->distance() + 1;
2390 }
2391 make_info(dst, d);
2392 }
2393 if (src != dst) {
2394 // traversal edges useful during select
2395 find_info(dst)->edge_bwd.push(src);
2396 }
2397 }
2398 }
2399
2400 void PrintBFS::print_header() const {
2401 if (_dump_only) {
2402 return; // no header in dump only mode
2403 }
2404 _output->print("dist"); // distance
2405 if (_all_paths) {
2406 _output->print(" apd"); // all paths distance
2407 }
2408 if (_print_blocks) {
2409 _output->print(" [block head idom depth]"); // block
2410 }
2411 if (_print_old) {
2412 _output->print(" old"); // old node
2413 }
2414 _output->print(" dump\n"); // node dump
2415 _output->print_cr("---------------------------------------------");
2416 }
2417
2418 void PrintBFS::print_node(const Node* n) {
2419 if (_dump_only) {
2420 n->dump("\n", false, _output, &_dcc);
2421 return;
2422 }
2423 _output->print("%4d", find_info(n)->distance());// distance
2424 if (_all_paths) {
2425 Info* info = find_info(n);
2426 int apd = info->distance() + info->distance_from_target();
2427 _output->print("%4d", apd); // all paths distance
2428 }
2429 if (_print_blocks) {
2430 print_node_block(n); // block
2431 }
2432 if (_print_old) {
2433 print_node_idx(old_node(n)); // old node
2434 }
2435 _output->print(" ");
2436 n->dump("\n", false, _output, &_dcc); // node dump
2437 }
2438
2439 //------------------------------dump_bfs--------------------------------------
2440 // Call this from debugger
2441 // Useful for BFS traversal, shortest path, all path, loop detection, etc
2442 // Designed to be more readable, and provide additional info
2443 // To find all options, run:
2444 // find_node(0)->dump_bfs(0,0,"H")
2445 void Node::dump_bfs(const int max_distance, Node* target, const char* options) const {
2446 dump_bfs(max_distance, target, options, tty);
2447 }
2448
2449 // Used to dump to stream.
2450 void Node::dump_bfs(const int max_distance, Node* target, const char* options, outputStream* st, const frame* fr) const {
2451 PrintBFS bfs(this, max_distance, target, options, st, fr);
2452 bfs.run();
2453 }
2454
2455 // Call this from debugger, with default arguments
2456 void Node::dump_bfs(const int max_distance) const {
2457 dump_bfs(max_distance, nullptr, nullptr);
2458 }
2459
2460 // Call this from debugger, with stack handling register arguments for IGV dumps.
2461 // Example: p find_node(741)->dump_bfs(7, find_node(741), "c+A!", $sp, $fp, $pc).
2462 void Node::dump_bfs(const int max_distance, Node* target, const char* options, void* sp, void* fp, void* pc) const {
2463 frame fr(sp, fp, pc);
2464 dump_bfs(max_distance, target, options, tty, &fr);
2465 }
2466
2467 // -----------------------------dump_idx---------------------------------------
2468 void Node::dump_idx(bool align, outputStream* st, DumpConfig* dc) const {
2469 if (dc != nullptr) {
2470 dc->pre_dump(st, this);
2471 }
2472 Compile* C = Compile::current();
2473 bool is_new = C->node_arena()->contains(this);
2474 if (align) { // print prefix empty spaces$
2475 // +1 for leading digit, +1 for "o"
2476 uint max_width = (C->unique() == 0 ? 0 : static_cast<uint>(log10(static_cast<double>(C->unique())))) + 2;
2477 // +1 for leading digit, maybe +1 for "o"
2478 uint width = (_idx == 0 ? 0 : static_cast<uint>(log10(static_cast<double>(_idx)))) + 1 + (is_new ? 0 : 1);
2479 while (max_width > width) {
2480 st->print(" ");
2481 width++;
2482 }
2483 }
2484 if (!is_new) {
2485 st->print("o");
2486 }
2487 st->print("%d", _idx);
2488 if (dc != nullptr) {
2489 dc->post_dump(st);
2490 }
2491 }
2492
2493 // -----------------------------dump_name--------------------------------------
2494 void Node::dump_name(outputStream* st, DumpConfig* dc) const {
2495 if (dc != nullptr) {
2496 dc->pre_dump(st, this);
2497 }
2498 st->print("%s", Name());
2499 if (dc != nullptr) {
2500 dc->post_dump(st);
2501 }
2502 }
2503
2504 // -----------------------------Name-------------------------------------------
2505 extern const char *NodeClassNames[];
2506 const char *Node::Name() const { return NodeClassNames[Opcode()]; }
2507
2508 static bool is_disconnected(const Node* n) {
2509 for (uint i = 0; i < n->req(); i++) {
2510 if (n->in(i) != nullptr) return false;
2511 }
2512 return true;
2513 }
2514
2515 #ifdef ASSERT
2516 void Node::dump_orig(outputStream *st, bool print_key) const {
2517 Compile* C = Compile::current();
2518 Node* orig = _debug_orig;
2519 if (not_a_node(orig)) orig = nullptr;
2520 if (orig != nullptr && !C->node_arena()->contains(orig)) orig = nullptr;
2521 if (orig == nullptr) return;
2522 if (print_key) {
2523 st->print(" !orig=");
2524 }
2525 Node* fast = orig->debug_orig(); // tortoise & hare algorithm to detect loops
2526 if (not_a_node(fast)) fast = nullptr;
2527 while (orig != nullptr) {
2528 bool discon = is_disconnected(orig); // if discon, print [123] else 123
2529 if (discon) st->print("[");
2530 if (!Compile::current()->node_arena()->contains(orig))
2531 st->print("o");
2532 st->print("%d", orig->_idx);
2533 if (discon) st->print("]");
2534 orig = orig->debug_orig();
2535 if (not_a_node(orig)) orig = nullptr;
2536 if (orig != nullptr && !C->node_arena()->contains(orig)) orig = nullptr;
2537 if (orig != nullptr) st->print(",");
2538 if (fast != nullptr) {
2539 // Step fast twice for each single step of orig:
2540 fast = fast->debug_orig();
2541 if (not_a_node(fast)) fast = nullptr;
2542 if (fast != nullptr && fast != orig) {
2543 fast = fast->debug_orig();
2544 if (not_a_node(fast)) fast = nullptr;
2545 }
2546 if (fast == orig) {
2547 st->print("...");
2548 break;
2549 }
2550 }
2551 }
2552 }
2553
2554 void Node::set_debug_orig(Node* orig) {
2555 _debug_orig = orig;
2556 if (BreakAtNode == 0) return;
2557 if (not_a_node(orig)) orig = nullptr;
2558 int trip = 10;
2559 while (orig != nullptr) {
2560 if (orig->debug_idx() == BreakAtNode || (uintx)orig->_idx == BreakAtNode) {
2561 tty->print_cr("BreakAtNode: _idx=%d _debug_idx=" UINT64_FORMAT " orig._idx=%d orig._debug_idx=" UINT64_FORMAT,
2562 this->_idx, this->debug_idx(), orig->_idx, orig->debug_idx());
2563 BREAKPOINT;
2564 }
2565 orig = orig->debug_orig();
2566 if (not_a_node(orig)) orig = nullptr;
2567 if (trip-- <= 0) break;
2568 }
2569 }
2570 #endif //ASSERT
2571
2572 //------------------------------dump------------------------------------------
2573 // Dump a Node
2574 void Node::dump(const char* suffix, bool mark, outputStream* st, DumpConfig* dc) const {
2575 Compile* C = Compile::current();
2576 bool is_new = C->node_arena()->contains(this);
2577 C->_in_dump_cnt++;
2578
2579 // idx mark name ===
2580 dump_idx(true, st, dc);
2581 st->print(mark ? " >" : " ");
2582 dump_name(st, dc);
2583 st->print(" === ");
2584
2585 // Dump the required and precedence inputs
2586 dump_req(st, dc);
2587 dump_prec(st, dc);
2588 // Dump the outputs
2589 dump_out(st, dc);
2590
2591 if (is_disconnected(this)) {
2592 #ifdef ASSERT
2593 st->print(" [" UINT64_FORMAT "]", debug_idx());
2594 dump_orig(st);
2595 #endif
2596 st->cr();
2597 C->_in_dump_cnt--;
2598 return; // don't process dead nodes
2599 }
2600
2601 if (C->clone_map().value(_idx) != 0) {
2602 C->clone_map().dump(_idx, st);
2603 }
2604 // Dump node-specific info
2605 dump_spec(st);
2606 #ifdef ASSERT
2607 // Dump the non-reset _debug_idx
2608 if (Verbose && WizardMode) {
2609 st->print(" [" UINT64_FORMAT "]", debug_idx());
2610 }
2611 #endif
2612
2613 const Type *t = bottom_type();
2614
2615 if (t != nullptr && (t->isa_instptr() || t->isa_instklassptr())) {
2616 const TypeInstPtr *toop = t->isa_instptr();
2617 const TypeInstKlassPtr *tkls = t->isa_instklassptr();
2618 if (toop) {
2619 st->print(" Oop:");
2620 } else if (tkls) {
2621 st->print(" Klass:");
2622 }
2623 t->dump_on(st);
2624 } else if (t == Type::MEMORY) {
2625 st->print(" Memory:");
2626 MemNode::dump_adr_type(adr_type(), st);
2627 } else if (Verbose || WizardMode) {
2628 st->print(" Type:");
2629 if (t) {
2630 t->dump_on(st);
2631 } else {
2632 st->print("no type");
2633 }
2634 } else if (t->isa_vect() && this->is_MachSpillCopy()) {
2635 // Dump MachSpillcopy vector type.
2636 t->dump_on(st);
2637 }
2638 if (is_new) {
2639 DEBUG_ONLY(dump_orig(st));
2640 Node_Notes* nn = C->node_notes_at(_idx);
2641 if (nn != nullptr && !nn->is_clear()) {
2642 if (nn->jvms() != nullptr) {
2643 st->print(" !jvms:");
2644 nn->jvms()->dump_spec(st);
2645 }
2646 }
2647 }
2648 if (suffix) st->print("%s", suffix);
2649 C->_in_dump_cnt--;
2650 }
2651
2652 // call from debugger: dump node to tty with newline
2653 void Node::dump() const {
2654 dump("\n");
2655 }
2656
2657 //------------------------------dump_req--------------------------------------
2658 void Node::dump_req(outputStream* st, DumpConfig* dc) const {
2659 // Dump the required input edges
2660 for (uint i = 0; i < req(); i++) { // For all required inputs
2661 Node* d = in(i);
2662 if (d == nullptr) {
2663 st->print("_ ");
2664 } else if (not_a_node(d)) {
2665 st->print("not_a_node "); // uninitialized, sentinel, garbage, etc.
2666 } else {
2667 d->dump_idx(false, st, dc);
2668 st->print(" ");
2669 }
2670 }
2671 }
2672
2673
2674 //------------------------------dump_prec-------------------------------------
2675 void Node::dump_prec(outputStream* st, DumpConfig* dc) const {
2676 // Dump the precedence edges
2677 int any_prec = 0;
2678 for (uint i = req(); i < len(); i++) { // For all precedence inputs
2679 Node* p = in(i);
2680 if (p != nullptr) {
2681 if (!any_prec++) st->print(" |");
2682 if (not_a_node(p)) { st->print("not_a_node "); continue; }
2683 p->dump_idx(false, st, dc);
2684 st->print(" ");
2685 }
2686 }
2687 }
2688
2689 //------------------------------dump_out--------------------------------------
2690 void Node::dump_out(outputStream* st, DumpConfig* dc) const {
2691 // Delimit the output edges
2692 st->print(" [[ ");
2693 // Dump the output edges
2694 for (uint i = 0; i < _outcnt; i++) { // For all outputs
2695 Node* u = _out[i];
2696 if (u == nullptr) {
2697 st->print("_ ");
2698 } else if (not_a_node(u)) {
2699 st->print("not_a_node ");
2700 } else {
2701 u->dump_idx(false, st, dc);
2702 st->print(" ");
2703 }
2704 }
2705 st->print("]] ");
2706 }
2707
2708 //------------------------------dump-------------------------------------------
2709 // call from debugger: dump Node's inputs (or outputs if d negative)
2710 void Node::dump(int d) const {
2711 dump_bfs(abs(d), nullptr, (d > 0) ? "+$" : "-$");
2712 }
2713
2714 //------------------------------dump_ctrl--------------------------------------
2715 // call from debugger: dump Node's control inputs (or outputs if d negative)
2716 void Node::dump_ctrl(int d) const {
2717 dump_bfs(abs(d), nullptr, (d > 0) ? "+$c" : "-$c");
2718 }
2719
2720 //-----------------------------dump_compact------------------------------------
2721 void Node::dump_comp() const {
2722 this->dump_comp("\n");
2723 }
2724
2725 //-----------------------------dump_compact------------------------------------
2726 // Dump a Node in compact representation, i.e., just print its name and index.
2727 // Nodes can specify additional specifics to print in compact representation by
2728 // implementing dump_compact_spec.
2729 void Node::dump_comp(const char* suffix, outputStream *st) const {
2730 Compile* C = Compile::current();
2731 C->_in_dump_cnt++;
2732 st->print("%s(%d)", Name(), _idx);
2733 this->dump_compact_spec(st);
2734 if (suffix) {
2735 st->print("%s", suffix);
2736 }
2737 C->_in_dump_cnt--;
2738 }
2739
2740 // VERIFICATION CODE
2741 // Verify all nodes if verify_depth is negative
2742 void Node::verify(int verify_depth, VectorSet& visited, Node_List& worklist) {
2743 assert(verify_depth != 0, "depth should not be 0");
2744 Compile* C = Compile::current();
2745 uint last_index_on_current_depth = worklist.size() - 1;
2746 verify_depth--; // Visiting the first node on depth 1
2747 // Only add nodes to worklist if verify_depth is negative (visit all nodes) or greater than 0
2748 bool add_to_worklist = verify_depth != 0;
2749
2750 for (uint list_index = 0; list_index < worklist.size(); list_index++) {
2751 Node* n = worklist[list_index];
2752
2753 if (n->is_Con() && n->bottom_type() == Type::TOP) {
2754 if (C->cached_top_node() == nullptr) {
2755 C->set_cached_top_node((Node*)n);
2756 }
2757 assert(C->cached_top_node() == n, "TOP node must be unique");
2758 }
2759
2760 uint in_len = n->len();
2761 for (uint i = 0; i < in_len; i++) {
2762 Node* x = n->_in[i];
2763 if (!x || x->is_top()) {
2764 continue;
2765 }
2766
2767 // Verify my input has a def-use edge to me
2768 // Count use-def edges from n to x
2769 int cnt = 1;
2770 for (uint j = 0; j < i; j++) {
2771 if (n->_in[j] == x) {
2772 cnt++;
2773 break;
2774 }
2775 }
2776 if (cnt == 2) {
2777 // x is already checked as n's previous input, skip its duplicated def-use count checking
2778 continue;
2779 }
2780 for (uint j = i + 1; j < in_len; j++) {
2781 if (n->_in[j] == x) {
2782 cnt++;
2783 }
2784 }
2785
2786 // Count def-use edges from x to n
2787 uint max = x->_outcnt;
2788 for (uint k = 0; k < max; k++) {
2789 if (x->_out[k] == n) {
2790 cnt--;
2791 }
2792 }
2793 assert(cnt == 0, "mismatched def-use edge counts");
2794
2795 if (add_to_worklist && !visited.test_set(x->_idx)) {
2796 worklist.push(x);
2797 }
2798 }
2799
2800 if (verify_depth > 0 && list_index == last_index_on_current_depth) {
2801 // All nodes on this depth were processed and its inputs are on the worklist. Decrement verify_depth and
2802 // store the current last list index which is the last node in the list with the new depth. All nodes
2803 // added afterwards will have a new depth again. Stop adding new nodes if depth limit is reached (=0).
2804 verify_depth--;
2805 if (verify_depth == 0) {
2806 add_to_worklist = false;
2807 }
2808 last_index_on_current_depth = worklist.size() - 1;
2809 }
2810 }
2811 }
2812 #endif // not PRODUCT
2813
2814 //------------------------------Registers--------------------------------------
2815 // Do we Match on this edge index or not? Generally false for Control
2816 // and true for everything else. Weird for calls & returns.
2817 uint Node::match_edge(uint idx) const {
2818 return idx; // True for other than index 0 (control)
2819 }
2820
2821 // Register classes are defined for specific machines
2822 const RegMask &Node::out_RegMask() const {
2823 ShouldNotCallThis();
2824 return RegMask::EMPTY;
2825 }
2826
2827 const RegMask &Node::in_RegMask(uint) const {
2828 ShouldNotCallThis();
2829 return RegMask::EMPTY;
2830 }
2831
2832 void Node_Array::grow(uint i) {
2833 assert(i >= _max, "Should have been checked before, use maybe_grow?");
2834 assert(_max > 0, "invariant");
2835 uint old = _max;
2836 _max = next_power_of_2(i);
2837 _nodes = (Node**)_a->Arealloc( _nodes, old*sizeof(Node*),_max*sizeof(Node*));
2838 Copy::zero_to_bytes( &_nodes[old], (_max-old)*sizeof(Node*) );
2839 }
2840
2841 void Node_Array::insert(uint i, Node* n) {
2842 if (_nodes[_max - 1]) {
2843 grow(_max);
2844 }
2845 Copy::conjoint_words_to_higher((HeapWord*)&_nodes[i], (HeapWord*)&_nodes[i + 1], ((_max - i - 1) * sizeof(Node*)));
2846 _nodes[i] = n;
2847 }
2848
2849 void Node_Array::remove(uint i) {
2850 Copy::conjoint_words_to_lower((HeapWord*)&_nodes[i + 1], (HeapWord*)&_nodes[i], ((_max - i - 1) * sizeof(Node*)));
2851 _nodes[_max - 1] = nullptr;
2852 }
2853
2854 void Node_Array::dump() const {
2855 #ifndef PRODUCT
2856 for (uint i = 0; i < _max; i++) {
2857 Node* nn = _nodes[i];
2858 if (nn != nullptr) {
2859 tty->print("%5d--> ",i); nn->dump();
2860 }
2861 }
2862 #endif
2863 }
2864
2865 //--------------------------is_iteratively_computed------------------------------
2866 // Operation appears to be iteratively computed (such as an induction variable)
2867 // It is possible for this operation to return false for a loop-varying
2868 // value, if it appears (by local graph inspection) to be computed by a simple conditional.
2869 bool Node::is_iteratively_computed() {
2870 if (ideal_reg()) { // does operation have a result register?
2871 for (uint i = 1; i < req(); i++) {
2872 Node* n = in(i);
2873 if (n != nullptr && n->is_Phi()) {
2874 for (uint j = 1; j < n->req(); j++) {
2875 if (n->in(j) == this) {
2876 return true;
2877 }
2878 }
2879 }
2880 }
2881 }
2882 return false;
2883 }
2884
2885 //--------------------------find_similar------------------------------
2886 // Return a node with opcode "opc" and same inputs as "this" if one can
2887 // be found; Otherwise return null;
2888 Node* Node::find_similar(int opc) {
2889 if (req() >= 2) {
2890 Node* def = in(1);
2891 if (def && def->outcnt() >= 2) {
2892 for (DUIterator_Fast dmax, i = def->fast_outs(dmax); i < dmax; i++) {
2893 Node* use = def->fast_out(i);
2894 if (use != this &&
2895 use->Opcode() == opc &&
2896 use->req() == req() &&
2897 has_same_inputs_as(use)) {
2898 return use;
2899 }
2900 }
2901 }
2902 }
2903 return nullptr;
2904 }
2905
2906 bool Node::has_same_inputs_as(const Node* other) const {
2907 assert(req() == other->req(), "should have same number of inputs");
2908 for (uint j = 0; j < other->req(); j++) {
2909 if (in(j) != other->in(j)) {
2910 return false;
2911 }
2912 }
2913 return true;
2914 }
2915
2916 Node* Node::unique_multiple_edges_out_or_null() const {
2917 Node* use = nullptr;
2918 for (DUIterator_Fast kmax, k = fast_outs(kmax); k < kmax; k++) {
2919 Node* u = fast_out(k);
2920 if (use == nullptr) {
2921 use = u; // first use
2922 } else if (u != use) {
2923 return nullptr; // not unique
2924 } else {
2925 // secondary use
2926 }
2927 }
2928 return use;
2929 }
2930
2931 //--------------------------unique_ctrl_out_or_null-------------------------
2932 // Return the unique control out if only one. Null if none or more than one.
2933 Node* Node::unique_ctrl_out_or_null() const {
2934 Node* found = nullptr;
2935 for (uint i = 0; i < outcnt(); i++) {
2936 Node* use = raw_out(i);
2937 if (use->is_CFG() && use != this) {
2938 if (found != nullptr) {
2939 return nullptr;
2940 }
2941 found = use;
2942 }
2943 }
2944 return found;
2945 }
2946
2947 //--------------------------unique_ctrl_out------------------------------
2948 // Return the unique control out. Asserts if none or more than one control out.
2949 Node* Node::unique_ctrl_out() const {
2950 Node* ctrl = unique_ctrl_out_or_null();
2951 assert(ctrl != nullptr, "control out is assumed to be unique");
2952 return ctrl;
2953 }
2954
2955 void Node::ensure_control_or_add_prec(Node* c) {
2956 if (in(0) == nullptr) {
2957 set_req(0, c);
2958 } else if (in(0) != c) {
2959 add_prec(c);
2960 }
2961 }
2962
2963 void Node::add_prec_from(Node* n) {
2964 for (uint i = n->req(); i < n->len(); i++) {
2965 Node* prec = n->in(i);
2966 if (prec != nullptr) {
2967 add_prec(prec);
2968 }
2969 }
2970 }
2971
2972 bool Node::is_dead_loop_safe() const {
2973 if (is_Phi()) {
2974 return true;
2975 }
2976 if (is_Proj() && in(0) == nullptr) {
2977 return true;
2978 }
2979 if ((_flags & (Flag_is_dead_loop_safe | Flag_is_Con)) != 0) {
2980 if (!is_Proj()) {
2981 return true;
2982 }
2983 if (in(0)->is_Allocate()) {
2984 return false;
2985 }
2986 // MemNode::can_see_stored_value() peeks through the boxing call
2987 if (in(0)->is_CallStaticJava() && in(0)->as_CallStaticJava()->is_boxing_method()) {
2988 return false;
2989 }
2990 return true;
2991 }
2992 return false;
2993 }
2994
2995 bool Node::is_div_or_mod(BasicType bt) const { return Opcode() == Op_Div(bt) || Opcode() == Op_Mod(bt) ||
2996 Opcode() == Op_UDiv(bt) || Opcode() == Op_UMod(bt); }
2997
2998 // `maybe_pure_function` is assumed to be the input of `this`. This is a bit redundant,
2999 // but we already have and need maybe_pure_function in all the call sites, so
3000 // it makes it obvious that the `maybe_pure_function` is the same node as in the caller,
3001 // while it takes more thinking to realize that a locally computed in(0) must be equal to
3002 // the local in the caller.
3003 bool Node::is_data_proj_of_pure_function(const Node* maybe_pure_function) const {
3004 return Opcode() == Op_Proj && as_Proj()->_con == TypeFunc::Parms && maybe_pure_function->is_CallLeafPure();
3005 }
3006
3007 //=============================================================================
3008 //------------------------------yank-------------------------------------------
3009 // Find and remove
3010 void Node_List::yank( Node *n ) {
3011 uint i;
3012 for (i = 0; i < _cnt; i++) {
3013 if (_nodes[i] == n) {
3014 break;
3015 }
3016 }
3017
3018 if (i < _cnt) {
3019 _nodes[i] = _nodes[--_cnt];
3020 }
3021 }
3022
3023 //------------------------------dump-------------------------------------------
3024 void Node_List::dump() const {
3025 #ifndef PRODUCT
3026 for (uint i = 0; i < _cnt; i++) {
3027 if (_nodes[i]) {
3028 tty->print("%5d--> ", i);
3029 _nodes[i]->dump();
3030 }
3031 }
3032 #endif
3033 }
3034
3035 void Node_List::dump_simple() const {
3036 #ifndef PRODUCT
3037 for (uint i = 0; i < _cnt; i++) {
3038 if( _nodes[i] ) {
3039 tty->print(" %d", _nodes[i]->_idx);
3040 } else {
3041 tty->print(" null");
3042 }
3043 }
3044 #endif
3045 }
3046
3047 //=============================================================================
3048 //------------------------------remove-----------------------------------------
3049 void Unique_Node_List::remove(Node* n) {
3050 if (_in_worklist.test(n->_idx)) {
3051 for (uint i = 0; i < size(); i++) {
3052 if (_nodes[i] == n) {
3053 map(i, Node_List::pop());
3054 _in_worklist.remove(n->_idx);
3055 return;
3056 }
3057 }
3058 ShouldNotReachHere();
3059 }
3060 }
3061
3062 //-----------------------remove_useless_nodes----------------------------------
3063 // Remove useless nodes from worklist
3064 void Unique_Node_List::remove_useless_nodes(VectorSet &useful) {
3065 for (uint i = 0; i < size(); ++i) {
3066 Node *n = at(i);
3067 assert( n != nullptr, "Did not expect null entries in worklist");
3068 if (!useful.test(n->_idx)) {
3069 _in_worklist.remove(n->_idx);
3070 map(i, Node_List::pop());
3071 --i; // Visit popped node
3072 // If it was last entry, loop terminates since size() was also reduced
3073 }
3074 }
3075 }
3076
3077 //=============================================================================
3078 void Node_Stack::grow() {
3079 size_t old_top = pointer_delta(_inode_top,_inodes,sizeof(INode)); // save _top
3080 size_t old_max = pointer_delta(_inode_max,_inodes,sizeof(INode));
3081 size_t max = old_max << 1; // max * 2
3082 _inodes = REALLOC_ARENA_ARRAY(_a, INode, _inodes, old_max, max);
3083 _inode_max = _inodes + max;
3084 _inode_top = _inodes + old_top; // restore _top
3085 }
3086
3087 // Node_Stack is used to map nodes.
3088 Node* Node_Stack::find(uint idx) const {
3089 uint sz = size();
3090 for (uint i = 0; i < sz; i++) {
3091 if (idx == index_at(i)) {
3092 return node_at(i);
3093 }
3094 }
3095 return nullptr;
3096 }
3097
3098 //=============================================================================
3099 uint TypeNode::size_of() const { return sizeof(*this); }
3100 #ifndef PRODUCT
3101 void TypeNode::dump_spec(outputStream *st) const {
3102 if (!Verbose && !WizardMode) {
3103 // standard dump does this in Verbose and WizardMode
3104 st->print(" #"); _type->dump_on(st);
3105 }
3106 }
3107
3108 void TypeNode::dump_compact_spec(outputStream *st) const {
3109 st->print("#");
3110 _type->dump_on(st);
3111 }
3112 #endif
3113 uint TypeNode::hash() const {
3114 return Node::hash() + _type->hash();
3115 }
3116 bool TypeNode::cmp(const Node& n) const {
3117 return Type::equals(_type, n.as_Type()->_type);
3118 }
3119 const Type* TypeNode::bottom_type() const { return _type; }
3120 const Type* TypeNode::Value(PhaseGVN* phase) const { return _type; }
3121
3122 //------------------------------ideal_reg--------------------------------------
3123 uint TypeNode::ideal_reg() const {
3124 return _type->ideal_reg();
3125 }
3126
3127 void TypeNode::make_path_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, Node* ctrl_use, uint j, const char* phase_str) {
3128 Node* c = ctrl_use->in(j);
3129 if (igvn->type(c) != Type::TOP) {
3130 igvn->replace_input_of(ctrl_use, j, igvn->C->top());
3131 create_halt_path(igvn, c, loop, phase_str);
3132 }
3133 }
3134
3135 // This Type node is dead. It could be because the type that it captures and the type of the node computed from its
3136 // inputs do not intersect anymore. That node has some uses along some control flow paths. Those control flow paths must
3137 // be unreachable as using a dead value makes no sense. For the Type node to capture a narrowed down type, some control
3138 // flow construct must guard the Type node (an If node usually). When the Type node becomes dead, the guard usually
3139 // constant folds and the control flow that leads to the Type node becomes unreachable. There are cases where that
3140 // doesn't happen, however. They are handled here by following uses of the Type node until a CFG or a Phi to find dead
3141 // paths. The dead paths are then replaced by a Halt node.
3142 void TypeNode::make_paths_from_here_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, const char* phase_str) {
3143 Unique_Node_List wq;
3144 wq.push(this);
3145 for (uint i = 0; i < wq.size(); ++i) {
3146 Node* n = wq.at(i);
3147 for (DUIterator_Fast kmax, k = n->fast_outs(kmax); k < kmax; k++) {
3148 Node* u = n->fast_out(k);
3149 if (u->is_CFG()) {
3150 assert(!u->is_Region(), "Can't reach a Region without going through a Phi");
3151 make_path_dead(igvn, loop, u, 0, phase_str);
3152 } else if (u->is_Phi()) {
3153 Node* r = u->in(0);
3154 assert(r->is_Region() || r->is_top(), "unexpected Phi's control");
3155 if (r->is_Region()) {
3156 for (uint j = 1; j < u->req(); ++j) {
3157 if (u->in(j) == n && r->in(j) != nullptr) {
3158 make_path_dead(igvn, loop, r, j, phase_str);
3159 }
3160 }
3161 }
3162 } else {
3163 wq.push(u);
3164 }
3165 }
3166 }
3167 }
3168
3169 void TypeNode::create_halt_path(PhaseIterGVN* igvn, Node* c, PhaseIdealLoop* loop, const char* phase_str) const {
3170 Node* frame = new ParmNode(igvn->C->start(), TypeFunc::FramePtr);
3171 if (loop == nullptr) {
3172 igvn->register_new_node_with_optimizer(frame);
3173 } else {
3174 loop->register_new_node(frame, igvn->C->start());
3175 }
3176
3177 stringStream ss;
3178 ss.print("dead path discovered by TypeNode during %s", phase_str);
3179
3180 Node* halt = new HaltNode(c, frame, ss.as_string(igvn->C->comp_arena()));
3181 if (loop == nullptr) {
3182 igvn->register_new_node_with_optimizer(halt);
3183 } else {
3184 loop->register_control(halt, loop->ltree_root(), c);
3185 }
3186 igvn->add_input_to(igvn->C->root(), halt);
3187 }
3188
3189 Node* TypeNode::Ideal(PhaseGVN* phase, bool can_reshape) {
3190 if (KillPathsReachableByDeadTypeNode && can_reshape && Value(phase) == Type::TOP) {
3191 PhaseIterGVN* igvn = phase->is_IterGVN();
3192 Node* top = igvn->C->top();
3193 ResourceMark rm;
3194 make_paths_from_here_dead(igvn, nullptr, "igvn");
3195 return top;
3196 }
3197
3198 return Node::Ideal(phase, can_reshape);
3199 }
3200