1 /*
2 * Copyright (c) 1997, 2025, 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/loopnode.hpp"
37 #include "opto/machnode.hpp"
38 #include "opto/matcher.hpp"
39 #include "opto/node.hpp"
40 #include "opto/opcodes.hpp"
41 #include "opto/regmask.hpp"
42 #include "opto/rootnode.hpp"
43 #include "opto/type.hpp"
44 #include "utilities/copy.hpp"
45 #include "utilities/macros.hpp"
46 #include "utilities/powerOfTwo.hpp"
47 #include "utilities/stringUtils.hpp"
48
49 class RegMask;
50 // #include "phase.hpp"
51 class PhaseTransform;
52 class PhaseGVN;
53
54 // Arena we are currently building Nodes in
55 const uint Node::NotAMachineReg = 0xffff0000;
56
57 #ifndef PRODUCT
58 extern uint nodes_created;
59 #endif
60 #ifdef __clang__
61 #pragma clang diagnostic push
62 #pragma GCC diagnostic ignored "-Wuninitialized"
63 #endif
64
65 #ifdef ASSERT
66
67 //-------------------------- construct_node------------------------------------
68 // Set a breakpoint here to identify where a particular node index is built.
69 void Node::verify_construction() {
70 _debug_orig = nullptr;
71 // The decimal digits of _debug_idx are <compile_id> followed by 10 digits of <_idx>
72 Compile* C = Compile::current();
73 assert(C->unique() < (INT_MAX - 1), "Node limit exceeded INT_MAX");
74 uint64_t new_debug_idx = (uint64_t)C->compile_id() * 10000000000 + _idx;
75 set_debug_idx(new_debug_idx);
76 if (!C->phase_optimize_finished()) {
77 // Only check assert during parsing and optimization phase. Skip it while generating code.
78 assert(C->live_nodes() <= C->max_node_limit(), "Live Node limit exceeded limit");
79 }
80 if (BreakAtNode != 0 && (_debug_idx == BreakAtNode || (uint64_t)_idx == BreakAtNode)) {
81 tty->print_cr("BreakAtNode: _idx=%d _debug_idx=" UINT64_FORMAT, _idx, _debug_idx);
82 BREAKPOINT;
83 }
84 #if OPTO_DU_ITERATOR_ASSERT
85 _last_del = nullptr;
86 _del_tick = 0;
87 #endif
88 _hash_lock = 0;
89 }
90
91
92 // #ifdef ASSERT ...
93
94 #if OPTO_DU_ITERATOR_ASSERT
95 void DUIterator_Common::sample(const Node* node) {
96 _vdui = VerifyDUIterators;
97 _node = node;
98 _outcnt = node->_outcnt;
99 _del_tick = node->_del_tick;
100 _last = nullptr;
101 }
102
103 void DUIterator_Common::verify(const Node* node, bool at_end_ok) {
104 assert(_node == node, "consistent iterator source");
105 assert(_del_tick == node->_del_tick, "no unexpected deletions allowed");
106 }
107
108 void DUIterator_Common::verify_resync() {
109 // Ensure that the loop body has just deleted the last guy produced.
110 const Node* node = _node;
111 // Ensure that at least one copy of the last-seen edge was deleted.
112 // Note: It is OK to delete multiple copies of the last-seen edge.
113 // Unfortunately, we have no way to verify that all the deletions delete
114 // that same edge. On this point we must use the Honor System.
115 assert(node->_del_tick >= _del_tick+1, "must have deleted an edge");
116 assert(node->_last_del == _last, "must have deleted the edge just produced");
117 // We liked this deletion, so accept the resulting outcnt and tick.
118 _outcnt = node->_outcnt;
119 _del_tick = node->_del_tick;
120 }
121
122 void DUIterator_Common::reset(const DUIterator_Common& that) {
123 if (this == &that) return; // ignore assignment to self
124 if (!_vdui) {
125 // We need to initialize everything, overwriting garbage values.
126 _last = that._last;
127 _vdui = that._vdui;
128 }
129 // Note: It is legal (though odd) for an iterator over some node x
130 // to be reassigned to iterate over another node y. Some doubly-nested
131 // progress loops depend on being able to do this.
132 const Node* node = that._node;
133 // Re-initialize everything, except _last.
134 _node = node;
135 _outcnt = node->_outcnt;
136 _del_tick = node->_del_tick;
137 }
138
139 void DUIterator::sample(const Node* node) {
140 DUIterator_Common::sample(node); // Initialize the assertion data.
141 _refresh_tick = 0; // No refreshes have happened, as yet.
142 }
143
144 void DUIterator::verify(const Node* node, bool at_end_ok) {
145 DUIterator_Common::verify(node, at_end_ok);
146 assert(_idx < node->_outcnt + (uint)at_end_ok, "idx in range");
147 }
148
149 void DUIterator::verify_increment() {
150 if (_refresh_tick & 1) {
151 // We have refreshed the index during this loop.
152 // Fix up _idx to meet asserts.
153 if (_idx > _outcnt) _idx = _outcnt;
154 }
155 verify(_node, true);
156 }
157
158 void DUIterator::verify_resync() {
159 // Note: We do not assert on _outcnt, because insertions are OK here.
160 DUIterator_Common::verify_resync();
161 // Make sure we are still in sync, possibly with no more out-edges:
162 verify(_node, true);
163 }
164
165 void DUIterator::reset(const DUIterator& that) {
166 if (this == &that) return; // self assignment is always a no-op
167 assert(that._refresh_tick == 0, "assign only the result of Node::outs()");
168 assert(that._idx == 0, "assign only the result of Node::outs()");
169 assert(_idx == that._idx, "already assigned _idx");
170 if (!_vdui) {
171 // We need to initialize everything, overwriting garbage values.
172 sample(that._node);
173 } else {
174 DUIterator_Common::reset(that);
175 if (_refresh_tick & 1) {
176 _refresh_tick++; // Clear the "was refreshed" flag.
177 }
178 assert(_refresh_tick < 2*100000, "DU iteration must converge quickly");
179 }
180 }
181
182 void DUIterator::refresh() {
183 DUIterator_Common::sample(_node); // Re-fetch assertion data.
184 _refresh_tick |= 1; // Set the "was refreshed" flag.
185 }
186
187 void DUIterator::verify_finish() {
188 // If the loop has killed the node, do not require it to re-run.
189 if (_node->_outcnt == 0) _refresh_tick &= ~1;
190 // If this assert triggers, it means that a loop used refresh_out_pos
191 // to re-synch an iteration index, but the loop did not correctly
192 // re-run itself, using a "while (progress)" construct.
193 // This iterator enforces the rule that you must keep trying the loop
194 // until it "runs clean" without any need for refreshing.
195 assert(!(_refresh_tick & 1), "the loop must run once with no refreshing");
196 }
197
198
199 void DUIterator_Fast::verify(const Node* node, bool at_end_ok) {
200 DUIterator_Common::verify(node, at_end_ok);
201 Node** out = node->_out;
202 uint cnt = node->_outcnt;
203 assert(cnt == _outcnt, "no insertions allowed");
204 assert(_outp >= out && _outp <= out + cnt - !at_end_ok, "outp in range");
205 // This last check is carefully designed to work for NO_OUT_ARRAY.
206 }
207
208 void DUIterator_Fast::verify_limit() {
209 const Node* node = _node;
210 verify(node, true);
211 assert(_outp == node->_out + node->_outcnt, "limit still correct");
212 }
213
214 void DUIterator_Fast::verify_resync() {
215 const Node* node = _node;
216 if (_outp == node->_out + _outcnt) {
217 // Note that the limit imax, not the pointer i, gets updated with the
218 // exact count of deletions. (For the pointer it's always "--i".)
219 assert(node->_outcnt+node->_del_tick == _outcnt+_del_tick, "no insertions allowed with deletion(s)");
220 // This is a limit pointer, with a name like "imax".
221 // Fudge the _last field so that the common assert will be happy.
222 _last = (Node*) node->_last_del;
223 DUIterator_Common::verify_resync();
224 } else {
225 assert(node->_outcnt < _outcnt, "no insertions allowed with deletion(s)");
226 // A normal internal pointer.
227 DUIterator_Common::verify_resync();
228 // Make sure we are still in sync, possibly with no more out-edges:
229 verify(node, true);
230 }
231 }
232
233 void DUIterator_Fast::verify_relimit(uint n) {
234 const Node* node = _node;
235 assert((int)n > 0, "use imax -= n only with a positive count");
236 // This must be a limit pointer, with a name like "imax".
237 assert(_outp == node->_out + node->_outcnt, "apply -= only to a limit (imax)");
238 // The reported number of deletions must match what the node saw.
239 assert(node->_del_tick == _del_tick + n, "must have deleted n edges");
240 // Fudge the _last field so that the common assert will be happy.
241 _last = (Node*) node->_last_del;
242 DUIterator_Common::verify_resync();
243 }
244
245 void DUIterator_Fast::reset(const DUIterator_Fast& that) {
246 assert(_outp == that._outp, "already assigned _outp");
247 DUIterator_Common::reset(that);
248 }
249
250 void DUIterator_Last::verify(const Node* node, bool at_end_ok) {
251 // at_end_ok means the _outp is allowed to underflow by 1
252 _outp += at_end_ok;
253 DUIterator_Fast::verify(node, at_end_ok); // check _del_tick, etc.
254 _outp -= at_end_ok;
255 assert(_outp == (node->_out + node->_outcnt) - 1, "pointer must point to end of nodes");
256 }
257
258 void DUIterator_Last::verify_limit() {
259 // Do not require the limit address to be resynched.
260 //verify(node, true);
261 assert(_outp == _node->_out, "limit still correct");
262 }
263
264 void DUIterator_Last::verify_step(uint num_edges) {
265 assert((int)num_edges > 0, "need non-zero edge count for loop progress");
266 _outcnt -= num_edges;
267 _del_tick += num_edges;
268 // Make sure we are still in sync, possibly with no more out-edges:
269 const Node* node = _node;
270 verify(node, true);
271 assert(node->_last_del == _last, "must have deleted the edge just produced");
272 }
273
274 #endif //OPTO_DU_ITERATOR_ASSERT
275
276
277 #endif //ASSERT
278
279
280 // This constant used to initialize _out may be any non-null value.
281 // The value null is reserved for the top node only.
282 #define NO_OUT_ARRAY ((Node**)-1)
283
284 // Out-of-line code from node constructors.
285 // Executed only when extra debug info. is being passed around.
286 static void init_node_notes(Compile* C, int idx, Node_Notes* nn) {
287 C->set_node_notes_at(idx, nn);
288 }
289
290 // Shared initialization code.
291 inline int Node::Init(int req) {
292 Compile* C = Compile::current();
293 int idx = C->next_unique();
294 NOT_PRODUCT(_igv_idx = C->next_igv_idx());
295
296 // Allocate memory for the necessary number of edges.
297 if (req > 0) {
298 // Allocate space for _in array to have double alignment.
299 _in = (Node **) ((char *) (C->node_arena()->AmallocWords(req * sizeof(void*))));
300 }
301 // If there are default notes floating around, capture them:
302 Node_Notes* nn = C->default_node_notes();
303 if (nn != nullptr) init_node_notes(C, idx, nn);
304
305 // Note: At this point, C is dead,
306 // and we begin to initialize the new Node.
307
308 _cnt = _max = req;
309 _outcnt = _outmax = 0;
310 _class_id = Class_Node;
311 _flags = 0;
312 _out = NO_OUT_ARRAY;
313 return idx;
314 }
315
316 //------------------------------Node-------------------------------------------
317 // Create a Node, with a given number of required edges.
318 Node::Node(uint req)
319 : _idx(Init(req))
320 #ifdef ASSERT
321 , _parse_idx(_idx)
322 #endif
323 {
324 assert( req < Compile::current()->max_node_limit() - NodeLimitFudgeFactor, "Input limit exceeded" );
325 DEBUG_ONLY( verify_construction() );
326 NOT_PRODUCT(nodes_created++);
327 if (req == 0) {
328 _in = nullptr;
329 } else {
330 Node** to = _in;
331 for(uint i = 0; i < req; i++) {
332 to[i] = nullptr;
333 }
334 }
335 }
336
337 //------------------------------Node-------------------------------------------
338 Node::Node(Node *n0)
339 : _idx(Init(1))
340 #ifdef ASSERT
341 , _parse_idx(_idx)
342 #endif
343 {
344 DEBUG_ONLY( verify_construction() );
345 NOT_PRODUCT(nodes_created++);
346 assert( is_not_dead(n0), "can not use dead node");
347 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
348 }
349
350 //------------------------------Node-------------------------------------------
351 Node::Node(Node *n0, Node *n1)
352 : _idx(Init(2))
353 #ifdef ASSERT
354 , _parse_idx(_idx)
355 #endif
356 {
357 DEBUG_ONLY( verify_construction() );
358 NOT_PRODUCT(nodes_created++);
359 assert( is_not_dead(n0), "can not use dead node");
360 assert( is_not_dead(n1), "can not use dead node");
361 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
362 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
363 }
364
365 //------------------------------Node-------------------------------------------
366 Node::Node(Node *n0, Node *n1, Node *n2)
367 : _idx(Init(3))
368 #ifdef ASSERT
369 , _parse_idx(_idx)
370 #endif
371 {
372 DEBUG_ONLY( verify_construction() );
373 NOT_PRODUCT(nodes_created++);
374 assert( is_not_dead(n0), "can not use dead node");
375 assert( is_not_dead(n1), "can not use dead node");
376 assert( is_not_dead(n2), "can not use dead node");
377 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
378 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
379 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
380 }
381
382 //------------------------------Node-------------------------------------------
383 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3)
384 : _idx(Init(4))
385 #ifdef ASSERT
386 , _parse_idx(_idx)
387 #endif
388 {
389 DEBUG_ONLY( verify_construction() );
390 NOT_PRODUCT(nodes_created++);
391 assert( is_not_dead(n0), "can not use dead node");
392 assert( is_not_dead(n1), "can not use dead node");
393 assert( is_not_dead(n2), "can not use dead node");
394 assert( is_not_dead(n3), "can not use dead node");
395 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
396 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
397 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
398 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
399 }
400
401 //------------------------------Node-------------------------------------------
402 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3, Node *n4)
403 : _idx(Init(5))
404 #ifdef ASSERT
405 , _parse_idx(_idx)
406 #endif
407 {
408 DEBUG_ONLY( verify_construction() );
409 NOT_PRODUCT(nodes_created++);
410 assert( is_not_dead(n0), "can not use dead node");
411 assert( is_not_dead(n1), "can not use dead node");
412 assert( is_not_dead(n2), "can not use dead node");
413 assert( is_not_dead(n3), "can not use dead node");
414 assert( is_not_dead(n4), "can not use dead node");
415 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
416 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
417 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
418 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
419 _in[4] = n4; if (n4 != nullptr) n4->add_out((Node *)this);
420 }
421
422 //------------------------------Node-------------------------------------------
423 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
424 Node *n4, Node *n5)
425 : _idx(Init(6))
426 #ifdef ASSERT
427 , _parse_idx(_idx)
428 #endif
429 {
430 DEBUG_ONLY( verify_construction() );
431 NOT_PRODUCT(nodes_created++);
432 assert( is_not_dead(n0), "can not use dead node");
433 assert( is_not_dead(n1), "can not use dead node");
434 assert( is_not_dead(n2), "can not use dead node");
435 assert( is_not_dead(n3), "can not use dead node");
436 assert( is_not_dead(n4), "can not use dead node");
437 assert( is_not_dead(n5), "can not use dead node");
438 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
439 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
440 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
441 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
442 _in[4] = n4; if (n4 != nullptr) n4->add_out((Node *)this);
443 _in[5] = n5; if (n5 != nullptr) n5->add_out((Node *)this);
444 }
445
446 //------------------------------Node-------------------------------------------
447 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
448 Node *n4, Node *n5, Node *n6)
449 : _idx(Init(7))
450 #ifdef ASSERT
451 , _parse_idx(_idx)
452 #endif
453 {
454 DEBUG_ONLY( verify_construction() );
455 NOT_PRODUCT(nodes_created++);
456 assert( is_not_dead(n0), "can not use dead node");
457 assert( is_not_dead(n1), "can not use dead node");
458 assert( is_not_dead(n2), "can not use dead node");
459 assert( is_not_dead(n3), "can not use dead node");
460 assert( is_not_dead(n4), "can not use dead node");
461 assert( is_not_dead(n5), "can not use dead node");
462 assert( is_not_dead(n6), "can not use dead node");
463 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
464 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
465 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
466 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
467 _in[4] = n4; if (n4 != nullptr) n4->add_out((Node *)this);
468 _in[5] = n5; if (n5 != nullptr) n5->add_out((Node *)this);
469 _in[6] = n6; if (n6 != nullptr) n6->add_out((Node *)this);
470 }
471
472 #ifdef __clang__
473 #pragma clang diagnostic pop
474 #endif
475
476
477 //------------------------------clone------------------------------------------
478 // Clone a Node.
479 Node *Node::clone() const {
480 Compile* C = Compile::current();
481 uint s = size_of(); // Size of inherited Node
482 Node *n = (Node*)C->node_arena()->AmallocWords(size_of() + _max*sizeof(Node*));
483 Copy::conjoint_words_to_lower((HeapWord*)this, (HeapWord*)n, s);
484 // Set the new input pointer array
485 n->_in = (Node**)(((char*)n)+s);
486 // Cannot share the old output pointer array, so kill it
487 n->_out = NO_OUT_ARRAY;
488 // And reset the counters to 0
489 n->_outcnt = 0;
490 n->_outmax = 0;
491 // Unlock this guy, since he is not in any hash table.
492 DEBUG_ONLY(n->_hash_lock = 0);
493 // Walk the old node's input list to duplicate its edges
494 uint i;
495 for( i = 0; i < len(); i++ ) {
496 Node *x = in(i);
497 n->_in[i] = x;
498 if (x != nullptr) x->add_out(n);
499 }
500 if (is_macro()) {
501 C->add_macro_node(n);
502 }
503 if (is_expensive()) {
504 C->add_expensive_node(n);
505 }
506 if (for_post_loop_opts_igvn()) {
507 // Don't add cloned node to Compile::_for_post_loop_opts_igvn list automatically.
508 // If it is applicable, it will happen anyway when the cloned node is registered with IGVN.
509 n->remove_flag(Node::NodeFlags::Flag_for_post_loop_opts_igvn);
510 }
511 if (for_merge_stores_igvn()) {
512 // Don't add cloned node to Compile::_for_merge_stores_igvn list automatically.
513 // If it is applicable, it will happen anyway when the cloned node is registered with IGVN.
514 n->remove_flag(Node::NodeFlags::Flag_for_merge_stores_igvn);
515 }
516 if (n->is_ParsePredicate()) {
517 C->add_parse_predicate(n->as_ParsePredicate());
518 }
519 if (n->is_OpaqueTemplateAssertionPredicate()) {
520 C->add_template_assertion_predicate_opaque(n->as_OpaqueTemplateAssertionPredicate());
521 }
522
523 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
524 bs->register_potential_barrier_node(n);
525
526 n->set_idx(C->next_unique()); // Get new unique index as well
527 NOT_PRODUCT(n->_igv_idx = C->next_igv_idx());
528 DEBUG_ONLY( n->verify_construction() );
529 NOT_PRODUCT(nodes_created++);
530 // Do not patch over the debug_idx of a clone, because it makes it
531 // impossible to break on the clone's moment of creation.
532 //DEBUG_ONLY( n->set_debug_idx( debug_idx() ) );
533
534 C->copy_node_notes_to(n, (Node*) this);
535
536 // MachNode clone
537 uint nopnds;
538 if (this->is_Mach() && (nopnds = this->as_Mach()->num_opnds()) > 0) {
539 MachNode *mach = n->as_Mach();
540 MachNode *mthis = this->as_Mach();
541 // Get address of _opnd_array.
542 // It should be the same offset since it is the clone of this node.
543 MachOper **from = mthis->_opnds;
544 MachOper **to = (MachOper **)((size_t)(&mach->_opnds) +
545 pointer_delta((const void*)from,
546 (const void*)(&mthis->_opnds), 1));
547 mach->_opnds = to;
548 for ( uint i = 0; i < nopnds; ++i ) {
549 to[i] = from[i]->clone();
550 }
551 }
552 if (this->is_MachProj()) {
553 // MachProjNodes contain register masks that may contain pointers to
554 // externally allocated memory. Make sure to use a proper constructor
555 // instead of just shallowly copying.
556 MachProjNode* mach = n->as_MachProj();
557 MachProjNode* mthis = this->as_MachProj();
558 new (&mach->_rout) RegMask(mthis->_rout);
559 }
560 if (n->is_Call()) {
561 // CallGenerator is linked to the original node.
562 CallGenerator* cg = n->as_Call()->generator();
563 if (cg != nullptr) {
564 CallGenerator* cloned_cg = cg->with_call_node(n->as_Call());
565 n->as_Call()->set_generator(cloned_cg);
566 }
567 }
568 if (n->is_SafePoint()) {
569 // Scalar replacement and macro expansion might modify the JVMState.
570 // Clone it to make sure it's not shared between SafePointNodes.
571 n->as_SafePoint()->clone_jvms(C);
572 n->as_SafePoint()->clone_replaced_nodes();
573 }
574 Compile::current()->record_modified_node(n);
575 return n; // Return the clone
576 }
577
578 //---------------------------setup_is_top--------------------------------------
579 // Call this when changing the top node, to reassert the invariants
580 // required by Node::is_top. See Compile::set_cached_top_node.
581 void Node::setup_is_top() {
582 if (this == (Node*)Compile::current()->top()) {
583 // This node has just become top. Kill its out array.
584 _outcnt = _outmax = 0;
585 _out = nullptr; // marker value for top
586 assert(is_top(), "must be top");
587 } else {
588 if (_out == nullptr) _out = NO_OUT_ARRAY;
589 assert(!is_top(), "must not be top");
590 }
591 }
592
593 //------------------------------~Node------------------------------------------
594 // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
595 void Node::destruct(PhaseValues* phase) {
596 Compile* compile = (phase != nullptr) ? phase->C : Compile::current();
597 if (phase != nullptr && phase->is_IterGVN()) {
598 phase->is_IterGVN()->_worklist.remove(this);
599 }
600 // If this is the most recently created node, reclaim its index. Otherwise,
601 // record the node as dead to keep liveness information accurate.
602 if ((uint)_idx+1 == compile->unique()) {
603 compile->set_unique(compile->unique()-1);
604 } else {
605 compile->record_dead_node(_idx);
606 }
607 // Clear debug info:
608 Node_Notes* nn = compile->node_notes_at(_idx);
609 if (nn != nullptr) nn->clear();
610 // Walk the input array, freeing the corresponding output edges
611 _cnt = _max; // forget req/prec distinction
612 uint i;
613 for( i = 0; i < _max; i++ ) {
614 set_req(i, nullptr);
615 //assert(def->out(def->outcnt()-1) == (Node *)this,"bad def-use hacking in reclaim");
616 }
617 assert(outcnt() == 0, "deleting a node must not leave a dangling use");
618
619 if (is_macro()) {
620 compile->remove_macro_node(this);
621 }
622 if (is_expensive()) {
623 compile->remove_expensive_node(this);
624 }
625 if (is_OpaqueTemplateAssertionPredicate()) {
626 compile->remove_template_assertion_predicate_opaque(as_OpaqueTemplateAssertionPredicate());
627 }
628 if (is_ParsePredicate()) {
629 compile->remove_parse_predicate(as_ParsePredicate());
630 }
631 if (for_post_loop_opts_igvn()) {
632 compile->remove_from_post_loop_opts_igvn(this);
633 }
634 if (for_merge_stores_igvn()) {
635 compile->remove_from_merge_stores_igvn(this);
636 }
637
638 if (is_SafePoint()) {
639 as_SafePoint()->delete_replaced_nodes();
640
641 if (is_CallStaticJava()) {
642 compile->remove_unstable_if_trap(as_CallStaticJava(), false);
643 }
644 }
645 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
646 bs->unregister_potential_barrier_node(this);
647
648 // See if the input array was allocated just prior to the object
649 int edge_size = _max*sizeof(void*);
650 int out_edge_size = _outmax*sizeof(void*);
651 char *in_array = ((char*)_in);
652 char *edge_end = in_array + edge_size;
653 char *out_array = (char*)(_out == NO_OUT_ARRAY? nullptr: _out);
654 int node_size = size_of();
655
656 #ifdef ASSERT
657 // We will not actually delete the storage, but we'll make the node unusable.
658 compile->remove_modified_node(this);
659 *(address*)this = badAddress; // smash the C++ vtbl, probably
660 _in = _out = (Node**) badAddress;
661 _max = _cnt = _outmax = _outcnt = 0;
662 #endif
663
664 // Free the output edge array
665 if (out_edge_size > 0) {
666 compile->node_arena()->Afree(out_array, out_edge_size);
667 }
668
669 // Free the input edge array and the node itself
670 if( edge_end == (char*)this ) {
671 // It was; free the input array and object all in one hit
672 #ifndef ASSERT
673 compile->node_arena()->Afree(in_array, edge_size+node_size);
674 #endif
675 } else {
676 // Free just the input array
677 compile->node_arena()->Afree(in_array, edge_size);
678
679 // Free just the object
680 #ifndef ASSERT
681 compile->node_arena()->Afree(this, node_size);
682 #endif
683 }
684 }
685
686 // Resize input or output array to grow it to the next larger power-of-2 bigger
687 // than len.
688 void Node::resize_array(Node**& array, node_idx_t& max_size, uint len, bool needs_clearing) {
689 Arena* arena = Compile::current()->node_arena();
690 uint new_max = max_size;
691 if (new_max == 0) {
692 max_size = 4;
693 array = (Node**)arena->Amalloc(4 * sizeof(Node*));
694 if (needs_clearing) {
695 array[0] = nullptr;
696 array[1] = nullptr;
697 array[2] = nullptr;
698 array[3] = nullptr;
699 }
700 return;
701 }
702 new_max = next_power_of_2(len);
703 assert(needs_clearing || (array != nullptr && array != NO_OUT_ARRAY), "out must have sensible value");
704 array = (Node**)arena->Arealloc(array, max_size * sizeof(Node*), new_max * sizeof(Node*));
705 if (needs_clearing) {
706 Copy::zero_to_bytes(&array[max_size], (new_max - max_size) * sizeof(Node*)); // null all new space
707 }
708 max_size = new_max; // Record new max length
709 // This assertion makes sure that Node::_max is wide enough to
710 // represent the numerical value of new_max.
711 assert(max_size > len, "int width of _max or _outmax is too small");
712 }
713
714 //------------------------------grow-------------------------------------------
715 // Grow the input array, making space for more edges
716 void Node::grow(uint len) {
717 resize_array(_in, _max, len, true);
718 }
719
720 //-----------------------------out_grow----------------------------------------
721 // Grow the input array, making space for more edges
722 void Node::out_grow(uint len) {
723 assert(!is_top(), "cannot grow a top node's out array");
724 resize_array(_out, _outmax, len, false);
725 }
726
727 #ifdef ASSERT
728 //------------------------------is_dead----------------------------------------
729 bool Node::is_dead() const {
730 // Mach and pinch point nodes may look like dead.
731 if( is_top() || is_Mach() || (Opcode() == Op_Node && _outcnt > 0) )
732 return false;
733 for( uint i = 0; i < _max; i++ )
734 if( _in[i] != nullptr )
735 return false;
736 return true;
737 }
738
739 bool Node::is_not_dead(const Node* n) {
740 return n == nullptr || !PhaseIterGVN::is_verify_def_use() || !(n->is_dead());
741 }
742
743 bool Node::is_reachable_from_root() const {
744 ResourceMark rm;
745 Unique_Node_List wq;
746 wq.push((Node*)this);
747 RootNode* root = Compile::current()->root();
748 for (uint i = 0; i < wq.size(); i++) {
749 Node* m = wq.at(i);
750 if (m == root) {
751 return true;
752 }
753 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) {
754 Node* u = m->fast_out(j);
755 wq.push(u);
756 }
757 }
758 return false;
759 }
760 #endif
761
762 //------------------------------is_unreachable---------------------------------
763 bool Node::is_unreachable(PhaseIterGVN &igvn) const {
764 assert(!is_Mach(), "doesn't work with MachNodes");
765 return outcnt() == 0 || igvn.type(this) == Type::TOP || (in(0) != nullptr && in(0)->is_top());
766 }
767
768 //------------------------------add_req----------------------------------------
769 // Add a new required input at the end
770 void Node::add_req( Node *n ) {
771 assert( is_not_dead(n), "can not use dead node");
772
773 // Look to see if I can move precedence down one without reallocating
774 if( (_cnt >= _max) || (in(_max-1) != nullptr) )
775 grow( _max+1 );
776
777 // Find a precedence edge to move
778 if( in(_cnt) != nullptr ) { // Next precedence edge is busy?
779 uint i;
780 for( i=_cnt; i<_max; i++ )
781 if( in(i) == nullptr ) // Find the null at end of prec edge list
782 break; // There must be one, since we grew the array
783 _in[i] = in(_cnt); // Move prec over, making space for req edge
784 }
785 _in[_cnt++] = n; // Stuff over old prec edge
786 if (n != nullptr) n->add_out((Node *)this);
787 Compile::current()->record_modified_node(this);
788 }
789
790 //---------------------------add_req_batch-------------------------------------
791 // Add a new required input at the end
792 void Node::add_req_batch( Node *n, uint m ) {
793 assert( is_not_dead(n), "can not use dead node");
794 // check various edge cases
795 if ((int)m <= 1) {
796 assert((int)m >= 0, "oob");
797 if (m != 0) add_req(n);
798 return;
799 }
800
801 // Look to see if I can move precedence down one without reallocating
802 if( (_cnt+m) > _max || _in[_max-m] )
803 grow( _max+m );
804
805 // Find a precedence edge to move
806 if( _in[_cnt] != nullptr ) { // Next precedence edge is busy?
807 uint i;
808 for( i=_cnt; i<_max; i++ )
809 if( _in[i] == nullptr ) // Find the null at end of prec edge list
810 break; // There must be one, since we grew the array
811 // Slide all the precs over by m positions (assume #prec << m).
812 Copy::conjoint_words_to_higher((HeapWord*)&_in[_cnt], (HeapWord*)&_in[_cnt+m], ((i-_cnt)*sizeof(Node*)));
813 }
814
815 // Stuff over the old prec edges
816 for(uint i=0; i<m; i++ ) {
817 _in[_cnt++] = n;
818 }
819
820 // Insert multiple out edges on the node.
821 if (n != nullptr && !n->is_top()) {
822 for(uint i=0; i<m; i++ ) {
823 n->add_out((Node *)this);
824 }
825 }
826 Compile::current()->record_modified_node(this);
827 }
828
829 //------------------------------del_req----------------------------------------
830 // Delete the required edge and compact the edge array
831 void Node::del_req( uint idx ) {
832 assert( idx < _cnt, "oob");
833 assert( !VerifyHashTableKeys || _hash_lock == 0,
834 "remove node from hash table before modifying it");
835 // First remove corresponding def-use edge
836 Node *n = in(idx);
837 if (n != nullptr) n->del_out((Node *)this);
838 _in[idx] = in(--_cnt); // Compact the array
839 // Avoid spec violation: Gap in prec edges.
840 close_prec_gap_at(_cnt);
841 Compile::current()->record_modified_node(this);
842 }
843
844 //------------------------------del_req_ordered--------------------------------
845 // Delete the required edge and compact the edge array with preserved order
846 void Node::del_req_ordered( uint idx ) {
847 assert( idx < _cnt, "oob");
848 assert( !VerifyHashTableKeys || _hash_lock == 0,
849 "remove node from hash table before modifying it");
850 // First remove corresponding def-use edge
851 Node *n = in(idx);
852 if (n != nullptr) n->del_out((Node *)this);
853 if (idx < --_cnt) { // Not last edge ?
854 Copy::conjoint_words_to_lower((HeapWord*)&_in[idx+1], (HeapWord*)&_in[idx], ((_cnt-idx)*sizeof(Node*)));
855 }
856 // Avoid spec violation: Gap in prec edges.
857 close_prec_gap_at(_cnt);
858 Compile::current()->record_modified_node(this);
859 }
860
861 //------------------------------ins_req----------------------------------------
862 // Insert a new required input at the end
863 void Node::ins_req( uint idx, Node *n ) {
864 assert( is_not_dead(n), "can not use dead node");
865 add_req(nullptr); // Make space
866 assert( idx < _max, "Must have allocated enough space");
867 // Slide over
868 if(_cnt-idx-1 > 0) {
869 Copy::conjoint_words_to_higher((HeapWord*)&_in[idx], (HeapWord*)&_in[idx+1], ((_cnt-idx-1)*sizeof(Node*)));
870 }
871 _in[idx] = n; // Stuff over old required edge
872 if (n != nullptr) n->add_out((Node *)this); // Add reciprocal def-use edge
873 Compile::current()->record_modified_node(this);
874 }
875
876 //-----------------------------find_edge---------------------------------------
877 int Node::find_edge(Node* n) {
878 for (uint i = 0; i < len(); i++) {
879 if (_in[i] == n) return i;
880 }
881 return -1;
882 }
883
884 //----------------------------replace_edge-------------------------------------
885 int Node::replace_edge(Node* old, Node* neww, PhaseGVN* gvn) {
886 if (old == neww) return 0; // nothing to do
887 uint nrep = 0;
888 for (uint i = 0; i < len(); i++) {
889 if (in(i) == old) {
890 if (i < req()) {
891 if (gvn != nullptr) {
892 set_req_X(i, neww, gvn);
893 } else {
894 set_req(i, neww);
895 }
896 } else {
897 assert(gvn == nullptr || gvn->is_IterGVN() == nullptr, "no support for igvn here");
898 assert(find_prec_edge(neww) == -1, "spec violation: duplicated prec edge (node %d -> %d)", _idx, neww->_idx);
899 set_prec(i, neww);
900 }
901 nrep++;
902 }
903 }
904 return nrep;
905 }
906
907 /**
908 * Replace input edges in the range pointing to 'old' node.
909 */
910 int Node::replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn) {
911 if (old == neww) return 0; // nothing to do
912 uint nrep = 0;
913 for (int i = start; i < end; i++) {
914 if (in(i) == old) {
915 set_req_X(i, neww, gvn);
916 nrep++;
917 }
918 }
919 return nrep;
920 }
921
922 //-------------------------disconnect_inputs-----------------------------------
923 // null out all inputs to eliminate incoming Def-Use edges.
924 void Node::disconnect_inputs(Compile* C) {
925 // the layout of Node::_in
926 // r: a required input, null is allowed
927 // p: a precedence, null values are all at the end
928 // -----------------------------------
929 // |r|...|r|p|...|p|null|...|null|
930 // | |
931 // req() len()
932 // -----------------------------------
933 for (uint i = 0; i < req(); ++i) {
934 if (in(i) != nullptr) {
935 set_req(i, nullptr);
936 }
937 }
938
939 // Remove precedence edges if any exist
940 // Note: Safepoints may have precedence edges, even during parsing
941 for (uint i = len(); i > req(); ) {
942 rm_prec(--i); // no-op if _in[i] is null
943 }
944
945 #ifdef ASSERT
946 // sanity check
947 for (uint i = 0; i < len(); ++i) {
948 assert(_in[i] == nullptr, "disconnect_inputs() failed!");
949 }
950 #endif
951
952 // Node::destruct requires all out edges be deleted first
953 // DEBUG_ONLY(destruct();) // no reuse benefit expected
954 C->record_dead_node(_idx);
955 }
956
957 //-----------------------------uncast---------------------------------------
958 // %%% Temporary, until we sort out CheckCastPP vs. CastPP.
959 // Strip away casting. (It is depth-limited.)
960 // Optionally, keep casts with dependencies.
961 Node* Node::uncast(bool keep_deps) const {
962 // Should be inline:
963 //return is_ConstraintCast() ? uncast_helper(this) : (Node*) this;
964 if (is_ConstraintCast()) {
965 return uncast_helper(this, keep_deps);
966 } else {
967 return (Node*) this;
968 }
969 }
970
971 // Find out of current node that matches opcode.
972 Node* Node::find_out_with(int opcode) {
973 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
974 Node* use = fast_out(i);
975 if (use->Opcode() == opcode) {
976 return use;
977 }
978 }
979 return nullptr;
980 }
981
982 // Return true if the current node has an out that matches opcode.
983 bool Node::has_out_with(int opcode) {
984 return (find_out_with(opcode) != nullptr);
985 }
986
987 // Return true if the current node has an out that matches any of the opcodes.
988 bool Node::has_out_with(int opcode1, int opcode2, int opcode3, int opcode4) {
989 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
990 int opcode = fast_out(i)->Opcode();
991 if (opcode == opcode1 || opcode == opcode2 || opcode == opcode3 || opcode == opcode4) {
992 return true;
993 }
994 }
995 return false;
996 }
997
998
999 //---------------------------uncast_helper-------------------------------------
1000 Node* Node::uncast_helper(const Node* p, bool keep_deps) {
1001 #ifdef ASSERT
1002 uint depth_count = 0;
1003 const Node* orig_p = p;
1004 #endif
1005
1006 while (true) {
1007 #ifdef ASSERT
1008 if (depth_count >= K) {
1009 orig_p->dump(4);
1010 if (p != orig_p)
1011 p->dump(1);
1012 }
1013 assert(depth_count++ < K, "infinite loop in Node::uncast_helper");
1014 #endif
1015 if (p == nullptr || p->req() != 2) {
1016 break;
1017 } else if (p->is_ConstraintCast()) {
1018 if (keep_deps && p->as_ConstraintCast()->carry_dependency()) {
1019 break; // stop at casts with dependencies
1020 }
1021 p = p->in(1);
1022 } else {
1023 break;
1024 }
1025 }
1026 return (Node*) p;
1027 }
1028
1029 //------------------------------add_prec---------------------------------------
1030 // Add a new precedence input. Precedence inputs are unordered, with
1031 // duplicates removed and nulls packed down at the end.
1032 void Node::add_prec( Node *n ) {
1033 assert( is_not_dead(n), "can not use dead node");
1034
1035 // Check for null at end
1036 if( _cnt >= _max || in(_max-1) )
1037 grow( _max+1 );
1038
1039 // Find a precedence edge to move
1040 uint i = _cnt;
1041 while( in(i) != nullptr ) {
1042 if (in(i) == n) return; // Avoid spec violation: duplicated prec edge.
1043 i++;
1044 }
1045 _in[i] = n; // Stuff prec edge over null
1046 if ( n != nullptr) n->add_out((Node *)this); // Add mirror edge
1047
1048 #ifdef ASSERT
1049 while ((++i)<_max) { assert(_in[i] == nullptr, "spec violation: Gap in prec edges (node %d)", _idx); }
1050 #endif
1051 Compile::current()->record_modified_node(this);
1052 }
1053
1054 //------------------------------rm_prec----------------------------------------
1055 // Remove a precedence input. Precedence inputs are unordered, with
1056 // duplicates removed and nulls packed down at the end.
1057 void Node::rm_prec( uint j ) {
1058 assert(j < _max, "oob: i=%d, _max=%d", j, _max);
1059 assert(j >= _cnt, "not a precedence edge");
1060 if (_in[j] == nullptr) return; // Avoid spec violation: Gap in prec edges.
1061 _in[j]->del_out((Node *)this);
1062 close_prec_gap_at(j);
1063 Compile::current()->record_modified_node(this);
1064 }
1065
1066 //------------------------------size_of----------------------------------------
1067 uint Node::size_of() const { return sizeof(*this); }
1068
1069 //------------------------------ideal_reg--------------------------------------
1070 uint Node::ideal_reg() const { return 0; }
1071
1072 //------------------------------jvms-------------------------------------------
1073 JVMState* Node::jvms() const { return nullptr; }
1074
1075 #ifdef ASSERT
1076 //------------------------------jvms-------------------------------------------
1077 bool Node::verify_jvms(const JVMState* using_jvms) const {
1078 for (JVMState* jvms = this->jvms(); jvms != nullptr; jvms = jvms->caller()) {
1079 if (jvms == using_jvms) return true;
1080 }
1081 return false;
1082 }
1083
1084 //------------------------------init_NodeProperty------------------------------
1085 void Node::init_NodeProperty() {
1086 assert(_max_classes <= max_juint, "too many NodeProperty classes");
1087 assert(max_flags() <= max_juint, "too many NodeProperty flags");
1088 }
1089
1090 //-----------------------------max_flags---------------------------------------
1091 juint Node::max_flags() {
1092 return (PD::_last_flag << 1) - 1; // allow flags combination
1093 }
1094 #endif
1095
1096 //------------------------------format-----------------------------------------
1097 // Print as assembly
1098 void Node::format( PhaseRegAlloc *, outputStream *st ) const {}
1099 //------------------------------emit-------------------------------------------
1100 // Emit bytes using C2_MacroAssembler
1101 void Node::emit(C2_MacroAssembler *masm, PhaseRegAlloc *ra_) const {}
1102 //------------------------------size-------------------------------------------
1103 // Size of instruction in bytes
1104 uint Node::size(PhaseRegAlloc *ra_) const { return 0; }
1105
1106 //------------------------------CFG Construction-------------------------------
1107 // Nodes that end basic blocks, e.g. IfTrue/IfFalse, JumpProjNode, Root,
1108 // Goto and Return.
1109 const Node *Node::is_block_proj() const { return nullptr; }
1110
1111 // Minimum guaranteed type
1112 const Type *Node::bottom_type() const { return Type::BOTTOM; }
1113
1114
1115 //------------------------------raise_bottom_type------------------------------
1116 // Get the worst-case Type output for this Node.
1117 void Node::raise_bottom_type(const Type* new_type) {
1118 if (is_Type()) {
1119 TypeNode *n = this->as_Type();
1120 if (VerifyAliases) {
1121 assert(new_type->higher_equal_speculative(n->type()), "new type must refine old type");
1122 }
1123 n->set_type(new_type);
1124 } else if (is_Load()) {
1125 LoadNode *n = this->as_Load();
1126 if (VerifyAliases) {
1127 assert(new_type->higher_equal_speculative(n->type()), "new type must refine old type");
1128 }
1129 n->set_type(new_type);
1130 }
1131 }
1132
1133 //------------------------------Identity---------------------------------------
1134 // Return a node that the given node is equivalent to.
1135 Node* Node::Identity(PhaseGVN* phase) {
1136 return this; // Default to no identities
1137 }
1138
1139 //------------------------------Value------------------------------------------
1140 // Compute a new Type for a node using the Type of the inputs.
1141 const Type* Node::Value(PhaseGVN* phase) const {
1142 return bottom_type(); // Default to worst-case Type
1143 }
1144
1145 //------------------------------Ideal------------------------------------------
1146 //
1147 // 'Idealize' the graph rooted at this Node.
1148 //
1149 // In order to be efficient and flexible there are some subtle invariants
1150 // these Ideal calls need to hold. Running with '-XX:VerifyIterativeGVN=1' checks
1151 // these invariants, although its too slow to have on by default. If you are
1152 // hacking an Ideal call, be sure to test with '-XX:VerifyIterativeGVN=1'
1153 //
1154 // The Ideal call almost arbitrarily reshape the graph rooted at the 'this'
1155 // pointer. If ANY change is made, it must return the root of the reshaped
1156 // graph - even if the root is the same Node. Example: swapping the inputs
1157 // to an AddINode gives the same answer and same root, but you still have to
1158 // return the 'this' pointer instead of null.
1159 //
1160 // You cannot return an OLD Node, except for the 'this' pointer. Use the
1161 // Identity call to return an old Node; basically if Identity can find
1162 // another Node have the Ideal call make no change and return null.
1163 // Example: AddINode::Ideal must check for add of zero; in this case it
1164 // returns null instead of doing any graph reshaping.
1165 //
1166 // You cannot modify any old Nodes except for the 'this' pointer. Due to
1167 // sharing there may be other users of the old Nodes relying on their current
1168 // semantics. Modifying them will break the other users.
1169 // Example: when reshape "(X+3)+4" into "X+7" you must leave the Node for
1170 // "X+3" unchanged in case it is shared.
1171 //
1172 // If you modify the 'this' pointer's inputs, you should use
1173 // 'set_req'. If you are making a new Node (either as the new root or
1174 // some new internal piece) you may use 'init_req' to set the initial
1175 // value. You can make a new Node with either 'new' or 'clone'. In
1176 // either case, def-use info is correctly maintained.
1177 //
1178 // Example: reshape "(X+3)+4" into "X+7":
1179 // set_req(1, in(1)->in(1));
1180 // set_req(2, phase->intcon(7));
1181 // return this;
1182 // Example: reshape "X*4" into "X<<2"
1183 // return new LShiftINode(in(1), phase->intcon(2));
1184 //
1185 // You must call 'phase->transform(X)' on any new Nodes X you make, except
1186 // for the returned root node. Example: reshape "X*31" with "(X<<5)-X".
1187 // Node *shift=phase->transform(new LShiftINode(in(1),phase->intcon(5)));
1188 // return new AddINode(shift, in(1));
1189 //
1190 // When making a Node for a constant use 'phase->makecon' or 'phase->intcon'.
1191 // These forms are faster than 'phase->transform(new ConNode())' and Do
1192 // The Right Thing with def-use info.
1193 //
1194 // You cannot bury the 'this' Node inside of a graph reshape. If the reshaped
1195 // graph uses the 'this' Node it must be the root. If you want a Node with
1196 // the same Opcode as the 'this' pointer use 'clone'.
1197 //
1198 Node *Node::Ideal(PhaseGVN *phase, bool can_reshape) {
1199 return nullptr; // Default to being Ideal already
1200 }
1201
1202 // Some nodes have specific Ideal subgraph transformations only if they are
1203 // unique users of specific nodes. Such nodes should be put on IGVN worklist
1204 // for the transformations to happen.
1205 bool Node::has_special_unique_user() const {
1206 assert(outcnt() == 1, "match only for unique out");
1207 Node* n = unique_out();
1208 int op = Opcode();
1209 if (this->is_Store()) {
1210 // Condition for back-to-back stores folding.
1211 return n->Opcode() == op && n->in(MemNode::Memory) == this;
1212 } else if ((this->is_Load() || this->is_DecodeN() || this->is_Phi()) && n->Opcode() == Op_MemBarAcquire) {
1213 // Condition for removing an unused LoadNode or DecodeNNode from the MemBarAcquire precedence input
1214 return true;
1215 } else if (this->is_Load() && n->is_Move()) {
1216 // Condition for MoveX2Y (LoadX mem) => LoadY mem
1217 return true;
1218 } else if (op == Op_AddL) {
1219 // Condition for convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
1220 return n->Opcode() == Op_ConvL2I && n->in(1) == this;
1221 } else if (op == Op_SubI || op == Op_SubL) {
1222 // Condition for subI(x,subI(y,z)) ==> subI(addI(x,z),y)
1223 return n->Opcode() == op && n->in(2) == this;
1224 } else if (is_If() && (n->is_IfFalse() || n->is_IfTrue())) {
1225 // See IfProjNode::Identity()
1226 return true;
1227 } else if ((is_IfFalse() || is_IfTrue()) && n->is_If()) {
1228 // See IfNode::fold_compares
1229 return true;
1230 } else if (n->Opcode() == Op_XorV || n->Opcode() == Op_XorVMask) {
1231 // Condition for XorVMask(VectorMaskCmp(x,y,cond), MaskAll(true)) ==> VectorMaskCmp(x,y,ncond)
1232 return true;
1233 } else {
1234 return false;
1235 }
1236 };
1237
1238 //--------------------------find_exact_control---------------------------------
1239 // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1240 Node* Node::find_exact_control(Node* ctrl) {
1241 if (ctrl == nullptr && this->is_Region())
1242 ctrl = this->as_Region()->is_copy();
1243
1244 if (ctrl != nullptr && ctrl->is_CatchProj()) {
1245 if (ctrl->as_CatchProj()->_con == CatchProjNode::fall_through_index)
1246 ctrl = ctrl->in(0);
1247 if (ctrl != nullptr && !ctrl->is_top())
1248 ctrl = ctrl->in(0);
1249 }
1250
1251 if (ctrl != nullptr && ctrl->is_Proj())
1252 ctrl = ctrl->in(0);
1253
1254 return ctrl;
1255 }
1256
1257 //--------------------------dominates------------------------------------------
1258 // Helper function for MemNode::all_controls_dominate().
1259 // Check if 'this' control node dominates or equal to 'sub' control node.
1260 // We already know that if any path back to Root or Start reaches 'this',
1261 // then all paths so, so this is a simple search for one example,
1262 // not an exhaustive search for a counterexample.
1263 Node::DomResult Node::dominates(Node* sub, Node_List &nlist) {
1264 assert(this->is_CFG(), "expecting control");
1265 assert(sub != nullptr && sub->is_CFG(), "expecting control");
1266
1267 // detect dead cycle without regions
1268 int iterations_without_region_limit = DominatorSearchLimit;
1269
1270 Node* orig_sub = sub;
1271 Node* dom = this;
1272 bool met_dom = false;
1273 nlist.clear();
1274
1275 // Walk 'sub' backward up the chain to 'dom', watching for regions.
1276 // After seeing 'dom', continue up to Root or Start.
1277 // If we hit a region (backward split point), it may be a loop head.
1278 // Keep going through one of the region's inputs. If we reach the
1279 // same region again, go through a different input. Eventually we
1280 // will either exit through the loop head, or give up.
1281 // (If we get confused, break out and return a conservative 'false'.)
1282 while (sub != nullptr) {
1283 if (sub->is_top()) {
1284 // Conservative answer for dead code.
1285 return DomResult::EncounteredDeadCode;
1286 }
1287 if (sub == dom) {
1288 if (nlist.size() == 0) {
1289 // No Region nodes except loops were visited before and the EntryControl
1290 // path was taken for loops: it did not walk in a cycle.
1291 return DomResult::Dominate;
1292 } else if (met_dom) {
1293 break; // already met before: walk in a cycle
1294 } else {
1295 // Region nodes were visited. Continue walk up to Start or Root
1296 // to make sure that it did not walk in a cycle.
1297 met_dom = true; // first time meet
1298 iterations_without_region_limit = DominatorSearchLimit; // Reset
1299 }
1300 }
1301 if (sub->is_Start() || sub->is_Root()) {
1302 // Success if we met 'dom' along a path to Start or Root.
1303 // We assume there are no alternative paths that avoid 'dom'.
1304 // (This assumption is up to the caller to ensure!)
1305 return met_dom ? DomResult::Dominate : DomResult::NotDominate;
1306 }
1307 Node* up = sub->in(0);
1308 // Normalize simple pass-through regions and projections:
1309 up = sub->find_exact_control(up);
1310 // If sub == up, we found a self-loop. Try to push past it.
1311 if (sub == up && sub->is_Loop()) {
1312 // Take loop entry path on the way up to 'dom'.
1313 up = sub->in(1); // in(LoopNode::EntryControl);
1314 } else if (sub == up && sub->is_Region() && sub->req() == 2) {
1315 // Take in(1) path on the way up to 'dom' for regions with only one input
1316 up = sub->in(1);
1317 } else if (sub == up && sub->is_Region()) {
1318 // Try both paths for Regions with 2 input paths (it may be a loop head).
1319 // It could give conservative 'false' answer without information
1320 // which region's input is the entry path.
1321 iterations_without_region_limit = DominatorSearchLimit; // Reset
1322
1323 bool region_was_visited_before = false;
1324 // Was this Region node visited before?
1325 // If so, we have reached it because we accidentally took a
1326 // loop-back edge from 'sub' back into the body of the loop,
1327 // and worked our way up again to the loop header 'sub'.
1328 // So, take the first unexplored path on the way up to 'dom'.
1329 for (int j = nlist.size() - 1; j >= 0; j--) {
1330 intptr_t ni = (intptr_t)nlist.at(j);
1331 Node* visited = (Node*)(ni & ~1);
1332 bool visited_twice_already = ((ni & 1) != 0);
1333 if (visited == sub) {
1334 if (visited_twice_already) {
1335 // Visited 2 paths, but still stuck in loop body. Give up.
1336 return DomResult::NotDominate;
1337 }
1338 // The Region node was visited before only once.
1339 // (We will repush with the low bit set, below.)
1340 nlist.remove(j);
1341 // We will find a new edge and re-insert.
1342 region_was_visited_before = true;
1343 break;
1344 }
1345 }
1346
1347 // Find an incoming edge which has not been seen yet; walk through it.
1348 assert(up == sub, "");
1349 uint skip = region_was_visited_before ? 1 : 0;
1350 for (uint i = 1; i < sub->req(); i++) {
1351 Node* in = sub->in(i);
1352 if (in != nullptr && !in->is_top() && in != sub) {
1353 if (skip == 0) {
1354 up = in;
1355 break;
1356 }
1357 --skip; // skip this nontrivial input
1358 }
1359 }
1360
1361 // Set 0 bit to indicate that both paths were taken.
1362 nlist.push((Node*)((intptr_t)sub + (region_was_visited_before ? 1 : 0)));
1363 }
1364
1365 if (up == sub) {
1366 break; // some kind of tight cycle
1367 }
1368 if (up == orig_sub && met_dom) {
1369 // returned back after visiting 'dom'
1370 break; // some kind of cycle
1371 }
1372 if (--iterations_without_region_limit < 0) {
1373 break; // dead cycle
1374 }
1375 sub = up;
1376 }
1377
1378 // Did not meet Root or Start node in pred. chain.
1379 return DomResult::NotDominate;
1380 }
1381
1382 //------------------------------remove_dead_region-----------------------------
1383 // This control node is dead. Follow the subgraph below it making everything
1384 // using it dead as well. This will happen normally via the usual IterGVN
1385 // worklist but this call is more efficient. Do not update use-def info
1386 // inside the dead region, just at the borders.
1387 static void kill_dead_code( Node *dead, PhaseIterGVN *igvn ) {
1388 // Con's are a popular node to re-hit in the hash table again.
1389 if( dead->is_Con() ) return;
1390
1391 ResourceMark rm;
1392 Node_List nstack;
1393 VectorSet dead_set; // notify uses only once
1394
1395 Node *top = igvn->C->top();
1396 nstack.push(dead);
1397 bool has_irreducible_loop = igvn->C->has_irreducible_loop();
1398
1399 while (nstack.size() > 0) {
1400 dead = nstack.pop();
1401 if (!dead_set.test_set(dead->_idx)) {
1402 // If dead has any live uses, those are now still attached. Notify them before we lose them.
1403 igvn->add_users_to_worklist(dead);
1404 }
1405 if (dead->Opcode() == Op_SafePoint) {
1406 dead->as_SafePoint()->disconnect_from_root(igvn);
1407 }
1408 if (dead->outcnt() > 0) {
1409 // Keep dead node on stack until all uses are processed.
1410 nstack.push(dead);
1411 // For all Users of the Dead... ;-)
1412 for (DUIterator_Last kmin, k = dead->last_outs(kmin); k >= kmin; ) {
1413 Node* use = dead->last_out(k);
1414 igvn->hash_delete(use); // Yank from hash table prior to mod
1415 if (use->in(0) == dead) { // Found another dead node
1416 assert (!use->is_Con(), "Control for Con node should be Root node.");
1417 use->set_req(0, top); // Cut dead edge to prevent processing
1418 nstack.push(use); // the dead node again.
1419 } else if (!has_irreducible_loop && // Backedge could be alive in irreducible loop
1420 use->is_Loop() && !use->is_Root() && // Don't kill Root (RootNode extends LoopNode)
1421 use->in(LoopNode::EntryControl) == dead) { // Dead loop if its entry is dead
1422 use->set_req(LoopNode::EntryControl, top); // Cut dead edge to prevent processing
1423 use->set_req(0, top); // Cut self edge
1424 nstack.push(use);
1425 } else { // Else found a not-dead user
1426 // Dead if all inputs are top or null
1427 bool dead_use = !use->is_Root(); // Keep empty graph alive
1428 for (uint j = 1; j < use->req(); j++) {
1429 Node* in = use->in(j);
1430 if (in == dead) { // Turn all dead inputs into TOP
1431 use->set_req(j, top);
1432 } else if (in != nullptr && !in->is_top()) {
1433 dead_use = false;
1434 }
1435 }
1436 if (dead_use) {
1437 if (use->is_Region()) {
1438 use->set_req(0, top); // Cut self edge
1439 }
1440 nstack.push(use);
1441 } else {
1442 igvn->_worklist.push(use);
1443 }
1444 }
1445 // Refresh the iterator, since any number of kills might have happened.
1446 k = dead->last_outs(kmin);
1447 }
1448 } else { // (dead->outcnt() == 0)
1449 // Done with outputs.
1450 igvn->hash_delete(dead);
1451 igvn->_worklist.remove(dead);
1452 igvn->set_type(dead, Type::TOP);
1453 // Kill all inputs to the dead guy
1454 for (uint i=0; i < dead->req(); i++) {
1455 Node *n = dead->in(i); // Get input to dead guy
1456 if (n != nullptr && !n->is_top()) { // Input is valid?
1457 dead->set_req(i, top); // Smash input away
1458 if (n->outcnt() == 0) { // Input also goes dead?
1459 if (!n->is_Con())
1460 nstack.push(n); // Clear it out as well
1461 } else if (n->outcnt() == 1 &&
1462 n->has_special_unique_user()) {
1463 igvn->add_users_to_worklist( n );
1464 } else if (n->outcnt() <= 2 && n->is_Store()) {
1465 // Push store's uses on worklist to enable folding optimization for
1466 // store/store and store/load to the same address.
1467 // The restriction (outcnt() <= 2) is the same as in set_req_X()
1468 // and remove_globally_dead_node().
1469 igvn->add_users_to_worklist( n );
1470 } else if (dead->is_data_proj_of_pure_function(n)) {
1471 igvn->_worklist.push(n);
1472 } else {
1473 BarrierSet::barrier_set()->barrier_set_c2()->enqueue_useful_gc_barrier(igvn, n);
1474 }
1475 }
1476 }
1477 igvn->C->remove_useless_node(dead);
1478 } // (dead->outcnt() == 0)
1479 } // while (nstack.size() > 0) for outputs
1480 return;
1481 }
1482
1483 //------------------------------remove_dead_region-----------------------------
1484 bool Node::remove_dead_region(PhaseGVN *phase, bool can_reshape) {
1485 Node *n = in(0);
1486 if( !n ) return false;
1487 // Lost control into this guy? I.e., it became unreachable?
1488 // Aggressively kill all unreachable code.
1489 if (can_reshape && n->is_top()) {
1490 kill_dead_code(this, phase->is_IterGVN());
1491 return false; // Node is dead.
1492 }
1493
1494 if( n->is_Region() && n->as_Region()->is_copy() ) {
1495 Node *m = n->nonnull_req();
1496 set_req(0, m);
1497 return true;
1498 }
1499 return false;
1500 }
1501
1502 //------------------------------hash-------------------------------------------
1503 // Hash function over Nodes.
1504 uint Node::hash() const {
1505 uint sum = 0;
1506 for( uint i=0; i<_cnt; i++ ) // Add in all inputs
1507 sum = (sum<<1)-(uintptr_t)in(i); // Ignore embedded nulls
1508 return (sum>>2) + _cnt + Opcode();
1509 }
1510
1511 //------------------------------cmp--------------------------------------------
1512 // Compare special parts of simple Nodes
1513 bool Node::cmp( const Node &n ) const {
1514 return true; // Must be same
1515 }
1516
1517 //------------------------------rematerialize-----------------------------------
1518 // Should we clone rather than spill this instruction?
1519 bool Node::rematerialize() const {
1520 if ( is_Mach() )
1521 return this->as_Mach()->rematerialize();
1522 else
1523 return (_flags & Flag_rematerialize) != 0;
1524 }
1525
1526 //------------------------------needs_anti_dependence_check---------------------
1527 // Nodes which use memory without consuming it, hence need antidependences.
1528 bool Node::needs_anti_dependence_check() const {
1529 if (req() < 2 || (_flags & Flag_needs_anti_dependence_check) == 0) {
1530 return false;
1531 }
1532 return in(1)->bottom_type()->has_memory();
1533 }
1534
1535 // Get an integer constant from a ConNode (or CastIINode).
1536 // Return a default value if there is no apparent constant here.
1537 const TypeInt* Node::find_int_type() const {
1538 if (this->is_Type()) {
1539 return this->as_Type()->type()->isa_int();
1540 } else if (this->is_Con()) {
1541 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1542 return this->bottom_type()->isa_int();
1543 }
1544 return nullptr;
1545 }
1546
1547 const TypeInteger* Node::find_integer_type(BasicType bt) const {
1548 if (this->is_Type()) {
1549 return this->as_Type()->type()->isa_integer(bt);
1550 } else if (this->is_Con()) {
1551 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1552 return this->bottom_type()->isa_integer(bt);
1553 }
1554 return nullptr;
1555 }
1556
1557 // Get a pointer constant from a ConstNode.
1558 // Returns the constant if it is a pointer ConstNode
1559 intptr_t Node::get_ptr() const {
1560 assert( Opcode() == Op_ConP, "" );
1561 return ((ConPNode*)this)->type()->is_ptr()->get_con();
1562 }
1563
1564 // Get a narrow oop constant from a ConNNode.
1565 intptr_t Node::get_narrowcon() const {
1566 assert( Opcode() == Op_ConN, "" );
1567 return ((ConNNode*)this)->type()->is_narrowoop()->get_con();
1568 }
1569
1570 // Get a long constant from a ConNode.
1571 // Return a default value if there is no apparent constant here.
1572 const TypeLong* Node::find_long_type() const {
1573 if (this->is_Type()) {
1574 return this->as_Type()->type()->isa_long();
1575 } else if (this->is_Con()) {
1576 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1577 return this->bottom_type()->isa_long();
1578 }
1579 return nullptr;
1580 }
1581
1582
1583 /**
1584 * Return a ptr type for nodes which should have it.
1585 */
1586 const TypePtr* Node::get_ptr_type() const {
1587 const TypePtr* tp = this->bottom_type()->make_ptr();
1588 #ifdef ASSERT
1589 if (tp == nullptr) {
1590 this->dump(1);
1591 assert((tp != nullptr), "unexpected node type");
1592 }
1593 #endif
1594 return tp;
1595 }
1596
1597 // Get a double constant from a ConstNode.
1598 // Returns the constant if it is a double ConstNode
1599 jdouble Node::getd() const {
1600 assert( Opcode() == Op_ConD, "" );
1601 return ((ConDNode*)this)->type()->is_double_constant()->getd();
1602 }
1603
1604 // Get a float constant from a ConstNode.
1605 // Returns the constant if it is a float ConstNode
1606 jfloat Node::getf() const {
1607 assert( Opcode() == Op_ConF, "" );
1608 return ((ConFNode*)this)->type()->is_float_constant()->getf();
1609 }
1610
1611 // Get a half float constant from a ConstNode.
1612 // Returns the constant if it is a float ConstNode
1613 jshort Node::geth() const {
1614 assert( Opcode() == Op_ConH, "" );
1615 return ((ConHNode*)this)->type()->is_half_float_constant()->geth();
1616 }
1617
1618 #ifndef PRODUCT
1619
1620 // Call this from debugger:
1621 Node* old_root() {
1622 Matcher* matcher = Compile::current()->matcher();
1623 if (matcher != nullptr) {
1624 Node* new_root = Compile::current()->root();
1625 Node* old_root = matcher->find_old_node(new_root);
1626 if (old_root != nullptr) {
1627 return old_root;
1628 }
1629 }
1630 tty->print("old_root: not found.\n");
1631 return nullptr;
1632 }
1633
1634 // BFS traverse all reachable nodes from start, call callback on them
1635 template <typename Callback>
1636 void visit_nodes(Node* start, Callback callback, bool traverse_output, bool only_ctrl) {
1637 Unique_Mixed_Node_List worklist;
1638 worklist.add(start);
1639 for (uint i = 0; i < worklist.size(); i++) {
1640 Node* n = worklist[i];
1641 callback(n);
1642 for (uint i = 0; i < n->len(); i++) {
1643 if (!only_ctrl || n->is_Region() || (n->Opcode() == Op_Root) || (i == TypeFunc::Control)) {
1644 // If only_ctrl is set: Add regions, the root node, or control inputs only
1645 worklist.add(n->in(i));
1646 }
1647 }
1648 if (traverse_output && !only_ctrl) {
1649 for (uint i = 0; i < n->outcnt(); i++) {
1650 worklist.add(n->raw_out(i));
1651 }
1652 }
1653 }
1654 }
1655
1656 // BFS traverse from start, return node with idx
1657 static Node* find_node_by_idx(Node* start, uint idx, bool traverse_output, bool only_ctrl) {
1658 ResourceMark rm;
1659 Node* result = nullptr;
1660 auto callback = [&] (Node* n) {
1661 if (n->_idx == idx) {
1662 if (result != nullptr) {
1663 tty->print("find_node_by_idx: " INTPTR_FORMAT " and " INTPTR_FORMAT " both have idx==%d\n",
1664 (uintptr_t)result, (uintptr_t)n, idx);
1665 }
1666 result = n;
1667 }
1668 };
1669 visit_nodes(start, callback, traverse_output, only_ctrl);
1670 return result;
1671 }
1672
1673 static int node_idx_cmp(const Node** n1, const Node** n2) {
1674 return (*n1)->_idx - (*n2)->_idx;
1675 }
1676
1677 static void find_nodes_by_name(Node* start, const char* name) {
1678 ResourceMark rm;
1679 GrowableArray<const Node*> ns;
1680 auto callback = [&] (const Node* n) {
1681 if (StringUtils::is_star_match(name, n->Name())) {
1682 ns.push(n);
1683 }
1684 };
1685 visit_nodes(start, callback, true, false);
1686 ns.sort(node_idx_cmp);
1687 for (int i = 0; i < ns.length(); i++) {
1688 ns.at(i)->dump();
1689 }
1690 }
1691
1692 static void find_nodes_by_dump(Node* start, const char* pattern) {
1693 ResourceMark rm;
1694 GrowableArray<const Node*> ns;
1695 auto callback = [&] (const Node* n) {
1696 stringStream stream;
1697 n->dump("", false, &stream);
1698 if (StringUtils::is_star_match(pattern, stream.base())) {
1699 ns.push(n);
1700 }
1701 };
1702 visit_nodes(start, callback, true, false);
1703 ns.sort(node_idx_cmp);
1704 for (int i = 0; i < ns.length(); i++) {
1705 ns.at(i)->dump();
1706 }
1707 }
1708
1709 // call from debugger: find node with name pattern in new/current graph
1710 // name can contain "*" in match pattern to match any characters
1711 // the matching is case insensitive
1712 void find_nodes_by_name(const char* name) {
1713 Node* root = Compile::current()->root();
1714 find_nodes_by_name(root, name);
1715 }
1716
1717 // call from debugger: find node with name pattern in old graph
1718 // name can contain "*" in match pattern to match any characters
1719 // the matching is case insensitive
1720 void find_old_nodes_by_name(const char* name) {
1721 Node* root = old_root();
1722 find_nodes_by_name(root, name);
1723 }
1724
1725 // call from debugger: find node with dump pattern in new/current graph
1726 // can contain "*" in match pattern to match any characters
1727 // the matching is case insensitive
1728 void find_nodes_by_dump(const char* pattern) {
1729 Node* root = Compile::current()->root();
1730 find_nodes_by_dump(root, pattern);
1731 }
1732
1733 // call from debugger: find node with name pattern in old graph
1734 // can contain "*" in match pattern to match any characters
1735 // the matching is case insensitive
1736 void find_old_nodes_by_dump(const char* pattern) {
1737 Node* root = old_root();
1738 find_nodes_by_dump(root, pattern);
1739 }
1740
1741 // Call this from debugger, search in same graph as n:
1742 Node* find_node(Node* n, const int idx) {
1743 return n->find(idx);
1744 }
1745
1746 // Call this from debugger, search in new nodes:
1747 Node* find_node(const int idx) {
1748 return Compile::current()->root()->find(idx);
1749 }
1750
1751 // Call this from debugger, search in old nodes:
1752 Node* find_old_node(const int idx) {
1753 Node* root = old_root();
1754 return (root == nullptr) ? nullptr : root->find(idx);
1755 }
1756
1757 // Call this from debugger, search in same graph as n:
1758 Node* find_ctrl(Node* n, const int idx) {
1759 return n->find_ctrl(idx);
1760 }
1761
1762 // Call this from debugger, search in new nodes:
1763 Node* find_ctrl(const int idx) {
1764 return Compile::current()->root()->find_ctrl(idx);
1765 }
1766
1767 // Call this from debugger, search in old nodes:
1768 Node* find_old_ctrl(const int idx) {
1769 Node* root = old_root();
1770 return (root == nullptr) ? nullptr : root->find_ctrl(idx);
1771 }
1772
1773 //------------------------------find_ctrl--------------------------------------
1774 // Find an ancestor to this node in the control history with given _idx
1775 Node* Node::find_ctrl(int idx) {
1776 return find(idx, true);
1777 }
1778
1779 //------------------------------find-------------------------------------------
1780 // Tries to find the node with the index |idx| starting from this node. If idx is negative,
1781 // the search also includes forward (out) edges. Returns null if not found.
1782 // If only_ctrl is set, the search will only be done on control nodes. Returns null if
1783 // not found or if the node to be found is not a control node (search will not find it).
1784 Node* Node::find(const int idx, bool only_ctrl) {
1785 ResourceMark rm;
1786 return find_node_by_idx(this, abs(idx), (idx < 0), only_ctrl);
1787 }
1788
1789 class PrintBFS {
1790 public:
1791 PrintBFS(const Node* start, const int max_distance, const Node* target, const char* options, outputStream* st, const frame* fr)
1792 : _start(start), _max_distance(max_distance), _target(target), _options(options), _output(st), _frame(fr),
1793 _dcc(this), _info_uid(cmpkey, hashkey) {}
1794
1795 void run();
1796 private:
1797 // pipeline steps
1798 bool configure();
1799 void collect();
1800 void select();
1801 void select_all();
1802 void select_all_paths();
1803 void select_shortest_path();
1804 void sort();
1805 void print();
1806
1807 // inputs
1808 const Node* _start;
1809 const int _max_distance;
1810 const Node* _target;
1811 const char* _options;
1812 outputStream* _output;
1813 const frame* _frame;
1814
1815 // options
1816 bool _traverse_inputs = false;
1817 bool _traverse_outputs = false;
1818 struct Filter {
1819 bool _control = false;
1820 bool _memory = false;
1821 bool _data = false;
1822 bool _mixed = false;
1823 bool _other = false;
1824 bool is_empty() const {
1825 return !(_control || _memory || _data || _mixed || _other);
1826 }
1827 void set_all() {
1828 _control = true;
1829 _memory = true;
1830 _data = true;
1831 _mixed = true;
1832 _other = true;
1833 }
1834 // Check if the filter accepts the node. Go by the type categories, but also all CFG nodes
1835 // are considered to have control.
1836 bool accepts(const Node* n) {
1837 const Type* t = n->bottom_type();
1838 return ( _data && t->has_category(Type::Category::Data) ) ||
1839 ( _memory && t->has_category(Type::Category::Memory) ) ||
1840 ( _mixed && t->has_category(Type::Category::Mixed) ) ||
1841 ( _control && (t->has_category(Type::Category::Control) || n->is_CFG()) ) ||
1842 ( _other && t->has_category(Type::Category::Other) );
1843 }
1844 };
1845 Filter _filter_visit;
1846 Filter _filter_boundary;
1847 bool _sort_idx = false;
1848 bool _all_paths = false;
1849 bool _use_color = false;
1850 bool _print_blocks = false;
1851 bool _print_old = false;
1852 bool _dump_only = false;
1853 bool _print_igv = false;
1854
1855 void print_options_help(bool print_examples);
1856 bool parse_options();
1857
1858 public:
1859 class DumpConfigColored : public Node::DumpConfig {
1860 public:
1861 DumpConfigColored(PrintBFS* bfs) : _bfs(bfs) {};
1862 virtual void pre_dump(outputStream* st, const Node* n);
1863 virtual void post_dump(outputStream* st);
1864 private:
1865 PrintBFS* _bfs;
1866 };
1867 private:
1868 DumpConfigColored _dcc;
1869
1870 // node info
1871 static Node* old_node(const Node* n); // mach node -> prior IR node
1872 void print_node_idx(const Node* n);
1873 void print_block_id(const Block* b);
1874 void print_node_block(const Node* n); // _pre_order, head idx, _idom, _dom_depth
1875
1876 // traversal data structures
1877 GrowableArray<const Node*> _worklist; // BFS queue
1878 void maybe_traverse(const Node* src, const Node* dst);
1879
1880 // node info annotation
1881 class Info {
1882 public:
1883 Info() : Info(nullptr, 0) {};
1884 Info(const Node* node, int distance)
1885 : _node(node), _distance_from_start(distance) {};
1886 const Node* node() const { return _node; };
1887 int distance() const { return _distance_from_start; };
1888 int distance_from_target() const { return _distance_from_target; }
1889 void set_distance_from_target(int d) { _distance_from_target = d; }
1890 GrowableArray<const Node*> edge_bwd; // pointing toward _start
1891 bool is_marked() const { return _mark; } // marked to keep during select
1892 void set_mark() { _mark = true; }
1893 private:
1894 const Node* _node;
1895 int _distance_from_start; // distance from _start
1896 int _distance_from_target = 0; // distance from _target if _all_paths
1897 bool _mark = false;
1898 };
1899 Dict _info_uid; // Node -> uid
1900 GrowableArray<Info> _info; // uid -> info
1901
1902 Info* find_info(const Node* n) {
1903 size_t uid = (size_t)_info_uid[n];
1904 if (uid == 0) {
1905 return nullptr;
1906 }
1907 return &_info.at((int)uid);
1908 }
1909
1910 void make_info(const Node* node, const int distance) {
1911 assert(find_info(node) == nullptr, "node does not yet have info");
1912 size_t uid = _info.length() + 1;
1913 _info_uid.Insert((void*)node, (void*)uid);
1914 _info.at_put_grow((int)uid, Info(node, distance));
1915 assert(find_info(node)->node() == node, "stored correct node");
1916 };
1917
1918 // filled by sort, printed by print
1919 GrowableArray<const Node*> _print_list;
1920
1921 // print header + node table
1922 void print_header() const;
1923 void print_node(const Node* n);
1924 };
1925
1926 void PrintBFS::run() {
1927 if (!configure()) {
1928 return;
1929 }
1930 collect();
1931 select();
1932 sort();
1933 print();
1934 }
1935
1936 // set up configuration for BFS and print
1937 bool PrintBFS::configure() {
1938 if (_max_distance < 0) {
1939 _output->print_cr("dump_bfs: max_distance must be non-negative!");
1940 return false;
1941 }
1942 return parse_options();
1943 }
1944
1945 // BFS traverse according to configuration, fill worklist and info
1946 void PrintBFS::collect() {
1947 maybe_traverse(_start, _start);
1948 int pos = 0;
1949 while (pos < _worklist.length()) {
1950 const Node* n = _worklist.at(pos++); // next node to traverse
1951 Info* info = find_info(n);
1952 if (!_filter_visit.accepts(n) && n != _start) {
1953 continue; // we hit boundary, do not traverse further
1954 }
1955 if (n != _start && n->is_Root()) {
1956 continue; // traversing through root node would lead to unrelated nodes
1957 }
1958 if (_traverse_inputs && _max_distance > info->distance()) {
1959 for (uint i = 0; i < n->req(); i++) {
1960 maybe_traverse(n, n->in(i));
1961 }
1962 }
1963 if (_traverse_outputs && _max_distance > info->distance()) {
1964 for (uint i = 0; i < n->outcnt(); i++) {
1965 maybe_traverse(n, n->raw_out(i));
1966 }
1967 }
1968 }
1969 }
1970
1971 // go through work list, mark those that we want to print
1972 void PrintBFS::select() {
1973 if (_target == nullptr ) {
1974 select_all();
1975 } else {
1976 if (find_info(_target) == nullptr) {
1977 _output->print_cr("Could not find target in BFS.");
1978 return;
1979 }
1980 if (_all_paths) {
1981 select_all_paths();
1982 } else {
1983 select_shortest_path();
1984 }
1985 }
1986 }
1987
1988 // take all nodes from BFS
1989 void PrintBFS::select_all() {
1990 for (int i = 0; i < _worklist.length(); i++) {
1991 const Node* n = _worklist.at(i);
1992 Info* info = find_info(n);
1993 info->set_mark();
1994 }
1995 }
1996
1997 // traverse backward from target, along edges found in BFS
1998 void PrintBFS::select_all_paths() {
1999 int pos = 0;
2000 GrowableArray<const Node*> backtrace;
2001 // start from target
2002 backtrace.push(_target);
2003 find_info(_target)->set_mark();
2004 // traverse backward
2005 while (pos < backtrace.length()) {
2006 const Node* n = backtrace.at(pos++);
2007 Info* info = find_info(n);
2008 for (int i = 0; i < info->edge_bwd.length(); i++) {
2009 // all backward edges
2010 const Node* back = info->edge_bwd.at(i);
2011 Info* back_info = find_info(back);
2012 if (!back_info->is_marked()) {
2013 // not yet found this on way back.
2014 back_info->set_distance_from_target(info->distance_from_target() + 1);
2015 if (back_info->distance_from_target() + back_info->distance() <= _max_distance) {
2016 // total distance is small enough
2017 back_info->set_mark();
2018 backtrace.push(back);
2019 }
2020 }
2021 }
2022 }
2023 }
2024
2025 void PrintBFS::select_shortest_path() {
2026 const Node* current = _target;
2027 while (true) {
2028 Info* info = find_info(current);
2029 info->set_mark();
2030 if (current == _start) {
2031 break;
2032 }
2033 // first edge -> leads us one step closer to _start
2034 current = info->edge_bwd.at(0);
2035 }
2036 }
2037
2038 // go through worklist in desired order, put the marked ones in print list
2039 void PrintBFS::sort() {
2040 if (_traverse_inputs && !_traverse_outputs) {
2041 // reverse order
2042 for (int i = _worklist.length() - 1; i >= 0; i--) {
2043 const Node* n = _worklist.at(i);
2044 Info* info = find_info(n);
2045 if (info->is_marked()) {
2046 _print_list.push(n);
2047 }
2048 }
2049 } else {
2050 // same order as worklist
2051 for (int i = 0; i < _worklist.length(); i++) {
2052 const Node* n = _worklist.at(i);
2053 Info* info = find_info(n);
2054 if (info->is_marked()) {
2055 _print_list.push(n);
2056 }
2057 }
2058 }
2059 if (_sort_idx) {
2060 _print_list.sort(node_idx_cmp);
2061 }
2062 }
2063
2064 // go through printlist and print
2065 void PrintBFS::print() {
2066 if (_print_list.length() > 0 ) {
2067 print_header();
2068 for (int i = 0; i < _print_list.length(); i++) {
2069 const Node* n = _print_list.at(i);
2070 print_node(n);
2071 }
2072 if (_print_igv) {
2073 Compile* C = Compile::current();
2074 C->init_igv();
2075 C->igv_print_graph_to_network(nullptr, _print_list, _frame);
2076 }
2077 } else {
2078 _output->print_cr("No nodes to print.");
2079 }
2080 }
2081
2082 void PrintBFS::print_options_help(bool print_examples) {
2083 _output->print_cr("Usage: node->dump_bfs(int max_distance, Node* target, char* options)");
2084 _output->print_cr("");
2085 _output->print_cr("Use cases:");
2086 _output->print_cr(" BFS traversal: no target required");
2087 _output->print_cr(" shortest path: set target");
2088 _output->print_cr(" all paths: set target and put 'A' in options");
2089 _output->print_cr(" detect loop: subcase of all paths, have start==target");
2090 _output->print_cr("");
2091 _output->print_cr("Arguments:");
2092 _output->print_cr(" this/start: staring point of BFS");
2093 _output->print_cr(" target:");
2094 _output->print_cr(" if null: simple BFS");
2095 _output->print_cr(" else: shortest path or all paths between this/start and target");
2096 _output->print_cr(" options:");
2097 _output->print_cr(" if null: same as \"cdmox@B\"");
2098 _output->print_cr(" else: use combination of following characters");
2099 _output->print_cr(" h: display this help info");
2100 _output->print_cr(" H: display this help info, with examples");
2101 _output->print_cr(" +: traverse in-edges (on if neither + nor -)");
2102 _output->print_cr(" -: traverse out-edges");
2103 _output->print_cr(" c: visit control nodes");
2104 _output->print_cr(" d: visit data nodes");
2105 _output->print_cr(" m: visit memory nodes");
2106 _output->print_cr(" o: visit other nodes");
2107 _output->print_cr(" x: visit mixed nodes");
2108 _output->print_cr(" C: boundary control nodes");
2109 _output->print_cr(" D: boundary data nodes");
2110 _output->print_cr(" M: boundary memory nodes");
2111 _output->print_cr(" O: boundary other nodes");
2112 _output->print_cr(" X: boundary mixed nodes");
2113 _output->print_cr(" #: display node category in color (not supported in all terminals)");
2114 _output->print_cr(" S: sort displayed nodes by node idx");
2115 _output->print_cr(" A: all paths (not just shortest path to target)");
2116 _output->print_cr(" @: print old nodes - before matching (if available)");
2117 _output->print_cr(" B: print scheduling blocks (if available)");
2118 _output->print_cr(" $: dump only, no header, no other columns");
2119 _output->print_cr(" !: show nodes on IGV (sent over network stream)");
2120 _output->print_cr(" (use preferably with dump_bfs(int, Node*, char*, void*, void*, void*)");
2121 _output->print_cr(" to produce a C2 stack trace along with the graph dump, see examples below)");
2122 _output->print_cr("");
2123 _output->print_cr("recursively follow edges to nodes with permitted visit types,");
2124 _output->print_cr("on the boundary additionally display nodes allowed in boundary types");
2125 _output->print_cr("Note: the categories can be overlapping. For example a mixed node");
2126 _output->print_cr(" can contain control and memory output. Some from the other");
2127 _output->print_cr(" category are also control (Halt, Return, etc).");
2128 _output->print_cr("");
2129 _output->print_cr("output columns:");
2130 _output->print_cr(" dist: BFS distance to this/start");
2131 _output->print_cr(" apd: all paths distance (d_outputart + d_target)");
2132 _output->print_cr(" block: block identifier, based on _pre_order");
2133 _output->print_cr(" head: first node in block");
2134 _output->print_cr(" idom: head node of idom block");
2135 _output->print_cr(" depth: depth of block (_dom_depth)");
2136 _output->print_cr(" old: old IR node - before matching");
2137 _output->print_cr(" dump: node->dump()");
2138 _output->print_cr("");
2139 _output->print_cr("Note: if none of the \"cmdxo\" characters are in the options string");
2140 _output->print_cr(" then we set all of them.");
2141 _output->print_cr(" This allows for short strings like \"#\" for colored input traversal");
2142 _output->print_cr(" or \"-#\" for colored output traversal.");
2143 if (print_examples) {
2144 _output->print_cr("");
2145 _output->print_cr("Examples:");
2146 _output->print_cr(" if->dump_bfs(10, 0, \"+cxo\")");
2147 _output->print_cr(" starting at some if node, traverse inputs recursively");
2148 _output->print_cr(" only along control (mixed and other can also be control)");
2149 _output->print_cr(" phi->dump_bfs(5, 0, \"-dxo\")");
2150 _output->print_cr(" starting at phi node, traverse outputs recursively");
2151 _output->print_cr(" only along data (mixed and other can also have data flow)");
2152 _output->print_cr(" find_node(385)->dump_bfs(3, 0, \"cdmox+#@B\")");
2153 _output->print_cr(" find inputs of node 385, up to 3 nodes up (+)");
2154 _output->print_cr(" traverse all nodes (cdmox), use colors (#)");
2155 _output->print_cr(" display old nodes and blocks, if they exist");
2156 _output->print_cr(" useful call to start with");
2157 _output->print_cr(" find_node(102)->dump_bfs(10, 0, \"dCDMOX-\")");
2158 _output->print_cr(" find non-data dependencies of a data node");
2159 _output->print_cr(" follow data node outputs until we find another category");
2160 _output->print_cr(" node as the boundary");
2161 _output->print_cr(" x->dump_bfs(10, y, 0)");
2162 _output->print_cr(" find shortest path from x to y, along any edge or node");
2163 _output->print_cr(" will not find a path if it is longer than 10");
2164 _output->print_cr(" useful to find how x and y are related");
2165 _output->print_cr(" find_node(741)->dump_bfs(20, find_node(746), \"c+\")");
2166 _output->print_cr(" find shortest control path between two nodes");
2167 _output->print_cr(" find_node(741)->dump_bfs(8, find_node(746), \"cdmox+A\")");
2168 _output->print_cr(" find all paths (A) between two nodes of length at most 8");
2169 _output->print_cr(" find_node(741)->dump_bfs(7, find_node(741), \"c+A\")");
2170 _output->print_cr(" find all control loops for this node");
2171 _output->print_cr(" find_node(741)->dump_bfs(7, find_node(741), \"c+A!\", $sp, $fp, $pc)");
2172 _output->print_cr(" same as above, but printing the resulting subgraph");
2173 _output->print_cr(" along with a C2 stack trace on IGV");
2174 }
2175 }
2176
2177 bool PrintBFS::parse_options() {
2178 if (_options == nullptr) {
2179 _options = "cdmox@B"; // default options
2180 }
2181 size_t len = strlen(_options);
2182 for (size_t i = 0; i < len; i++) {
2183 switch (_options[i]) {
2184 case '+':
2185 _traverse_inputs = true;
2186 break;
2187 case '-':
2188 _traverse_outputs = true;
2189 break;
2190 case 'c':
2191 _filter_visit._control = true;
2192 break;
2193 case 'm':
2194 _filter_visit._memory = true;
2195 break;
2196 case 'd':
2197 _filter_visit._data = true;
2198 break;
2199 case 'x':
2200 _filter_visit._mixed = true;
2201 break;
2202 case 'o':
2203 _filter_visit._other = true;
2204 break;
2205 case 'C':
2206 _filter_boundary._control = true;
2207 break;
2208 case 'M':
2209 _filter_boundary._memory = true;
2210 break;
2211 case 'D':
2212 _filter_boundary._data = true;
2213 break;
2214 case 'X':
2215 _filter_boundary._mixed = true;
2216 break;
2217 case 'O':
2218 _filter_boundary._other = true;
2219 break;
2220 case 'S':
2221 _sort_idx = true;
2222 break;
2223 case 'A':
2224 _all_paths = true;
2225 break;
2226 case '#':
2227 _use_color = true;
2228 break;
2229 case 'B':
2230 _print_blocks = true;
2231 break;
2232 case '@':
2233 _print_old = true;
2234 break;
2235 case '$':
2236 _dump_only = true;
2237 break;
2238 case '!':
2239 _print_igv = true;
2240 break;
2241 case 'h':
2242 print_options_help(false);
2243 return false;
2244 case 'H':
2245 print_options_help(true);
2246 return false;
2247 default:
2248 _output->print_cr("dump_bfs: Unrecognized option \'%c\'", _options[i]);
2249 _output->print_cr("for help, run: find_node(0)->dump_bfs(0,0,\"H\")");
2250 return false;
2251 }
2252 }
2253 if (!_traverse_inputs && !_traverse_outputs) {
2254 _traverse_inputs = true;
2255 }
2256 if (_filter_visit.is_empty()) {
2257 _filter_visit.set_all();
2258 }
2259 Compile* C = Compile::current();
2260 _print_old &= (C->matcher() != nullptr); // only show old if there are new
2261 _print_blocks &= (C->cfg() != nullptr); // only show blocks if available
2262 return true;
2263 }
2264
2265 void PrintBFS::DumpConfigColored::pre_dump(outputStream* st, const Node* n) {
2266 if (!_bfs->_use_color) {
2267 return;
2268 }
2269 Info* info = _bfs->find_info(n);
2270 if (info == nullptr || !info->is_marked()) {
2271 return;
2272 }
2273
2274 const Type* t = n->bottom_type();
2275 switch (t->category()) {
2276 case Type::Category::Data:
2277 st->print("\u001b[34m");
2278 break;
2279 case Type::Category::Memory:
2280 st->print("\u001b[32m");
2281 break;
2282 case Type::Category::Mixed:
2283 st->print("\u001b[35m");
2284 break;
2285 case Type::Category::Control:
2286 st->print("\u001b[31m");
2287 break;
2288 case Type::Category::Other:
2289 st->print("\u001b[33m");
2290 break;
2291 case Type::Category::Undef:
2292 n->dump();
2293 assert(false, "category undef ??");
2294 break;
2295 default:
2296 n->dump();
2297 assert(false, "not covered");
2298 break;
2299 }
2300 }
2301
2302 void PrintBFS::DumpConfigColored::post_dump(outputStream* st) {
2303 if (!_bfs->_use_color) {
2304 return;
2305 }
2306 st->print("\u001b[0m"); // white
2307 }
2308
2309 Node* PrintBFS::old_node(const Node* n) {
2310 Compile* C = Compile::current();
2311 if (C->matcher() == nullptr || !C->node_arena()->contains(n)) {
2312 return (Node*)nullptr;
2313 } else {
2314 return C->matcher()->find_old_node(n);
2315 }
2316 }
2317
2318 void PrintBFS::print_node_idx(const Node* n) {
2319 Compile* C = Compile::current();
2320 char buf[30];
2321 if (n == nullptr) {
2322 os::snprintf_checked(buf, sizeof(buf), "_"); // null
2323 } else if (C->node_arena()->contains(n)) {
2324 os::snprintf_checked(buf, sizeof(buf), "%d", n->_idx); // new node
2325 } else {
2326 os::snprintf_checked(buf, sizeof(buf), "o%d", n->_idx); // old node
2327 }
2328 _output->print("%6s", buf);
2329 }
2330
2331 void PrintBFS::print_block_id(const Block* b) {
2332 Compile* C = Compile::current();
2333 char buf[30];
2334 os::snprintf_checked(buf, sizeof(buf), "B%d", b->_pre_order);
2335 _output->print("%7s", buf);
2336 }
2337
2338 void PrintBFS::print_node_block(const Node* n) {
2339 Compile* C = Compile::current();
2340 Block* b = C->node_arena()->contains(n)
2341 ? C->cfg()->get_block_for_node(n)
2342 : nullptr; // guard against old nodes
2343 if (b == nullptr) {
2344 _output->print(" _"); // Block
2345 _output->print(" _"); // head
2346 _output->print(" _"); // idom
2347 _output->print(" _"); // depth
2348 } else {
2349 print_block_id(b);
2350 print_node_idx(b->head());
2351 if (b->_idom) {
2352 print_node_idx(b->_idom->head());
2353 } else {
2354 _output->print(" _"); // idom
2355 }
2356 _output->print("%6d ", b->_dom_depth);
2357 }
2358 }
2359
2360 // filter, and add to worklist, add info, note traversal edges
2361 void PrintBFS::maybe_traverse(const Node* src, const Node* dst) {
2362 if (dst != nullptr &&
2363 (_filter_visit.accepts(dst) ||
2364 _filter_boundary.accepts(dst) ||
2365 dst == _start)) { // correct category or start?
2366 if (find_info(dst) == nullptr) {
2367 // never visited - set up info
2368 _worklist.push(dst);
2369 int d = 0;
2370 if (dst != _start) {
2371 d = find_info(src)->distance() + 1;
2372 }
2373 make_info(dst, d);
2374 }
2375 if (src != dst) {
2376 // traversal edges useful during select
2377 find_info(dst)->edge_bwd.push(src);
2378 }
2379 }
2380 }
2381
2382 void PrintBFS::print_header() const {
2383 if (_dump_only) {
2384 return; // no header in dump only mode
2385 }
2386 _output->print("dist"); // distance
2387 if (_all_paths) {
2388 _output->print(" apd"); // all paths distance
2389 }
2390 if (_print_blocks) {
2391 _output->print(" [block head idom depth]"); // block
2392 }
2393 if (_print_old) {
2394 _output->print(" old"); // old node
2395 }
2396 _output->print(" dump\n"); // node dump
2397 _output->print_cr("---------------------------------------------");
2398 }
2399
2400 void PrintBFS::print_node(const Node* n) {
2401 if (_dump_only) {
2402 n->dump("\n", false, _output, &_dcc);
2403 return;
2404 }
2405 _output->print("%4d", find_info(n)->distance());// distance
2406 if (_all_paths) {
2407 Info* info = find_info(n);
2408 int apd = info->distance() + info->distance_from_target();
2409 _output->print("%4d", apd); // all paths distance
2410 }
2411 if (_print_blocks) {
2412 print_node_block(n); // block
2413 }
2414 if (_print_old) {
2415 print_node_idx(old_node(n)); // old node
2416 }
2417 _output->print(" ");
2418 n->dump("\n", false, _output, &_dcc); // node dump
2419 }
2420
2421 //------------------------------dump_bfs--------------------------------------
2422 // Call this from debugger
2423 // Useful for BFS traversal, shortest path, all path, loop detection, etc
2424 // Designed to be more readable, and provide additional info
2425 // To find all options, run:
2426 // find_node(0)->dump_bfs(0,0,"H")
2427 void Node::dump_bfs(const int max_distance, Node* target, const char* options) const {
2428 dump_bfs(max_distance, target, options, tty);
2429 }
2430
2431 // Used to dump to stream.
2432 void Node::dump_bfs(const int max_distance, Node* target, const char* options, outputStream* st, const frame* fr) const {
2433 PrintBFS bfs(this, max_distance, target, options, st, fr);
2434 bfs.run();
2435 }
2436
2437 // Call this from debugger, with default arguments
2438 void Node::dump_bfs(const int max_distance) const {
2439 dump_bfs(max_distance, nullptr, nullptr);
2440 }
2441
2442 // Call this from debugger, with stack handling register arguments for IGV dumps.
2443 // Example: p find_node(741)->dump_bfs(7, find_node(741), "c+A!", $sp, $fp, $pc).
2444 void Node::dump_bfs(const int max_distance, Node* target, const char* options, void* sp, void* fp, void* pc) const {
2445 frame fr(sp, fp, pc);
2446 dump_bfs(max_distance, target, options, tty, &fr);
2447 }
2448
2449 // -----------------------------dump_idx---------------------------------------
2450 void Node::dump_idx(bool align, outputStream* st, DumpConfig* dc) const {
2451 if (dc != nullptr) {
2452 dc->pre_dump(st, this);
2453 }
2454 Compile* C = Compile::current();
2455 bool is_new = C->node_arena()->contains(this);
2456 if (align) { // print prefix empty spaces$
2457 // +1 for leading digit, +1 for "o"
2458 uint max_width = (C->unique() == 0 ? 0 : static_cast<uint>(log10(static_cast<double>(C->unique())))) + 2;
2459 // +1 for leading digit, maybe +1 for "o"
2460 uint width = (_idx == 0 ? 0 : static_cast<uint>(log10(static_cast<double>(_idx)))) + 1 + (is_new ? 0 : 1);
2461 while (max_width > width) {
2462 st->print(" ");
2463 width++;
2464 }
2465 }
2466 if (!is_new) {
2467 st->print("o");
2468 }
2469 st->print("%d", _idx);
2470 if (dc != nullptr) {
2471 dc->post_dump(st);
2472 }
2473 }
2474
2475 // -----------------------------dump_name--------------------------------------
2476 void Node::dump_name(outputStream* st, DumpConfig* dc) const {
2477 if (dc != nullptr) {
2478 dc->pre_dump(st, this);
2479 }
2480 st->print("%s", Name());
2481 if (dc != nullptr) {
2482 dc->post_dump(st);
2483 }
2484 }
2485
2486 // -----------------------------Name-------------------------------------------
2487 extern const char *NodeClassNames[];
2488 const char *Node::Name() const { return NodeClassNames[Opcode()]; }
2489
2490 static bool is_disconnected(const Node* n) {
2491 for (uint i = 0; i < n->req(); i++) {
2492 if (n->in(i) != nullptr) return false;
2493 }
2494 return true;
2495 }
2496
2497 #ifdef ASSERT
2498 void Node::dump_orig(outputStream *st, bool print_key) const {
2499 Compile* C = Compile::current();
2500 Node* orig = _debug_orig;
2501 if (not_a_node(orig)) orig = nullptr;
2502 if (orig != nullptr && !C->node_arena()->contains(orig)) orig = nullptr;
2503 if (orig == nullptr) return;
2504 if (print_key) {
2505 st->print(" !orig=");
2506 }
2507 Node* fast = orig->debug_orig(); // tortoise & hare algorithm to detect loops
2508 if (not_a_node(fast)) fast = nullptr;
2509 while (orig != nullptr) {
2510 bool discon = is_disconnected(orig); // if discon, print [123] else 123
2511 if (discon) st->print("[");
2512 if (!Compile::current()->node_arena()->contains(orig))
2513 st->print("o");
2514 st->print("%d", orig->_idx);
2515 if (discon) st->print("]");
2516 orig = orig->debug_orig();
2517 if (not_a_node(orig)) orig = nullptr;
2518 if (orig != nullptr && !C->node_arena()->contains(orig)) orig = nullptr;
2519 if (orig != nullptr) st->print(",");
2520 if (fast != nullptr) {
2521 // Step fast twice for each single step of orig:
2522 fast = fast->debug_orig();
2523 if (not_a_node(fast)) fast = nullptr;
2524 if (fast != nullptr && fast != orig) {
2525 fast = fast->debug_orig();
2526 if (not_a_node(fast)) fast = nullptr;
2527 }
2528 if (fast == orig) {
2529 st->print("...");
2530 break;
2531 }
2532 }
2533 }
2534 }
2535
2536 void Node::set_debug_orig(Node* orig) {
2537 _debug_orig = orig;
2538 if (BreakAtNode == 0) return;
2539 if (not_a_node(orig)) orig = nullptr;
2540 int trip = 10;
2541 while (orig != nullptr) {
2542 if (orig->debug_idx() == BreakAtNode || (uintx)orig->_idx == BreakAtNode) {
2543 tty->print_cr("BreakAtNode: _idx=%d _debug_idx=" UINT64_FORMAT " orig._idx=%d orig._debug_idx=" UINT64_FORMAT,
2544 this->_idx, this->debug_idx(), orig->_idx, orig->debug_idx());
2545 BREAKPOINT;
2546 }
2547 orig = orig->debug_orig();
2548 if (not_a_node(orig)) orig = nullptr;
2549 if (trip-- <= 0) break;
2550 }
2551 }
2552 #endif //ASSERT
2553
2554 //------------------------------dump------------------------------------------
2555 // Dump a Node
2556 void Node::dump(const char* suffix, bool mark, outputStream* st, DumpConfig* dc) const {
2557 Compile* C = Compile::current();
2558 bool is_new = C->node_arena()->contains(this);
2559 C->_in_dump_cnt++;
2560
2561 // idx mark name ===
2562 dump_idx(true, st, dc);
2563 st->print(mark ? " >" : " ");
2564 dump_name(st, dc);
2565 st->print(" === ");
2566
2567 // Dump the required and precedence inputs
2568 dump_req(st, dc);
2569 dump_prec(st, dc);
2570 // Dump the outputs
2571 dump_out(st, dc);
2572
2573 if (is_disconnected(this)) {
2574 #ifdef ASSERT
2575 st->print(" [" UINT64_FORMAT "]", debug_idx());
2576 dump_orig(st);
2577 #endif
2578 st->cr();
2579 C->_in_dump_cnt--;
2580 return; // don't process dead nodes
2581 }
2582
2583 if (C->clone_map().value(_idx) != 0) {
2584 C->clone_map().dump(_idx, st);
2585 }
2586 // Dump node-specific info
2587 dump_spec(st);
2588 #ifdef ASSERT
2589 // Dump the non-reset _debug_idx
2590 if (Verbose && WizardMode) {
2591 st->print(" [" UINT64_FORMAT "]", debug_idx());
2592 }
2593 #endif
2594
2595 const Type *t = bottom_type();
2596
2597 if (t != nullptr && (t->isa_instptr() || t->isa_instklassptr())) {
2598 const TypeInstPtr *toop = t->isa_instptr();
2599 const TypeInstKlassPtr *tkls = t->isa_instklassptr();
2600 if (toop) {
2601 st->print(" Oop:");
2602 } else if (tkls) {
2603 st->print(" Klass:");
2604 }
2605 t->dump_on(st);
2606 } else if (t == Type::MEMORY) {
2607 st->print(" Memory:");
2608 MemNode::dump_adr_type(adr_type(), st);
2609 } else if (Verbose || WizardMode) {
2610 st->print(" Type:");
2611 if (t) {
2612 t->dump_on(st);
2613 } else {
2614 st->print("no type");
2615 }
2616 } else if (t->isa_vect() && this->is_MachSpillCopy()) {
2617 // Dump MachSpillcopy vector type.
2618 t->dump_on(st);
2619 }
2620 if (is_new) {
2621 DEBUG_ONLY(dump_orig(st));
2622 Node_Notes* nn = C->node_notes_at(_idx);
2623 if (nn != nullptr && !nn->is_clear()) {
2624 if (nn->jvms() != nullptr) {
2625 st->print(" !jvms:");
2626 nn->jvms()->dump_spec(st);
2627 }
2628 }
2629 }
2630 if (suffix) st->print("%s", suffix);
2631 C->_in_dump_cnt--;
2632 }
2633
2634 // call from debugger: dump node to tty with newline
2635 void Node::dump() const {
2636 dump("\n");
2637 }
2638
2639 //------------------------------dump_req--------------------------------------
2640 void Node::dump_req(outputStream* st, DumpConfig* dc) const {
2641 // Dump the required input edges
2642 for (uint i = 0; i < req(); i++) { // For all required inputs
2643 Node* d = in(i);
2644 if (d == nullptr) {
2645 st->print("_ ");
2646 } else if (not_a_node(d)) {
2647 st->print("not_a_node "); // uninitialized, sentinel, garbage, etc.
2648 } else {
2649 d->dump_idx(false, st, dc);
2650 st->print(" ");
2651 }
2652 }
2653 }
2654
2655
2656 //------------------------------dump_prec-------------------------------------
2657 void Node::dump_prec(outputStream* st, DumpConfig* dc) const {
2658 // Dump the precedence edges
2659 int any_prec = 0;
2660 for (uint i = req(); i < len(); i++) { // For all precedence inputs
2661 Node* p = in(i);
2662 if (p != nullptr) {
2663 if (!any_prec++) st->print(" |");
2664 if (not_a_node(p)) { st->print("not_a_node "); continue; }
2665 p->dump_idx(false, st, dc);
2666 st->print(" ");
2667 }
2668 }
2669 }
2670
2671 //------------------------------dump_out--------------------------------------
2672 void Node::dump_out(outputStream* st, DumpConfig* dc) const {
2673 // Delimit the output edges
2674 st->print(" [[ ");
2675 // Dump the output edges
2676 for (uint i = 0; i < _outcnt; i++) { // For all outputs
2677 Node* u = _out[i];
2678 if (u == nullptr) {
2679 st->print("_ ");
2680 } else if (not_a_node(u)) {
2681 st->print("not_a_node ");
2682 } else {
2683 u->dump_idx(false, st, dc);
2684 st->print(" ");
2685 }
2686 }
2687 st->print("]] ");
2688 }
2689
2690 //------------------------------dump-------------------------------------------
2691 // call from debugger: dump Node's inputs (or outputs if d negative)
2692 void Node::dump(int d) const {
2693 dump_bfs(abs(d), nullptr, (d > 0) ? "+$" : "-$");
2694 }
2695
2696 //------------------------------dump_ctrl--------------------------------------
2697 // call from debugger: dump Node's control inputs (or outputs if d negative)
2698 void Node::dump_ctrl(int d) const {
2699 dump_bfs(abs(d), nullptr, (d > 0) ? "+$c" : "-$c");
2700 }
2701
2702 //-----------------------------dump_compact------------------------------------
2703 void Node::dump_comp() const {
2704 this->dump_comp("\n");
2705 }
2706
2707 //-----------------------------dump_compact------------------------------------
2708 // Dump a Node in compact representation, i.e., just print its name and index.
2709 // Nodes can specify additional specifics to print in compact representation by
2710 // implementing dump_compact_spec.
2711 void Node::dump_comp(const char* suffix, outputStream *st) const {
2712 Compile* C = Compile::current();
2713 C->_in_dump_cnt++;
2714 st->print("%s(%d)", Name(), _idx);
2715 this->dump_compact_spec(st);
2716 if (suffix) {
2717 st->print("%s", suffix);
2718 }
2719 C->_in_dump_cnt--;
2720 }
2721
2722 // VERIFICATION CODE
2723 // Verify all nodes if verify_depth is negative
2724 void Node::verify(int verify_depth, VectorSet& visited, Node_List& worklist) {
2725 assert(verify_depth != 0, "depth should not be 0");
2726 Compile* C = Compile::current();
2727 uint last_index_on_current_depth = worklist.size() - 1;
2728 verify_depth--; // Visiting the first node on depth 1
2729 // Only add nodes to worklist if verify_depth is negative (visit all nodes) or greater than 0
2730 bool add_to_worklist = verify_depth != 0;
2731
2732 for (uint list_index = 0; list_index < worklist.size(); list_index++) {
2733 Node* n = worklist[list_index];
2734
2735 if (n->is_Con() && n->bottom_type() == Type::TOP) {
2736 if (C->cached_top_node() == nullptr) {
2737 C->set_cached_top_node((Node*)n);
2738 }
2739 assert(C->cached_top_node() == n, "TOP node must be unique");
2740 }
2741
2742 uint in_len = n->len();
2743 for (uint i = 0; i < in_len; i++) {
2744 Node* x = n->_in[i];
2745 if (!x || x->is_top()) {
2746 continue;
2747 }
2748
2749 // Verify my input has a def-use edge to me
2750 // Count use-def edges from n to x
2751 int cnt = 1;
2752 for (uint j = 0; j < i; j++) {
2753 if (n->_in[j] == x) {
2754 cnt++;
2755 break;
2756 }
2757 }
2758 if (cnt == 2) {
2759 // x is already checked as n's previous input, skip its duplicated def-use count checking
2760 continue;
2761 }
2762 for (uint j = i + 1; j < in_len; j++) {
2763 if (n->_in[j] == x) {
2764 cnt++;
2765 }
2766 }
2767
2768 // Count def-use edges from x to n
2769 uint max = x->_outcnt;
2770 for (uint k = 0; k < max; k++) {
2771 if (x->_out[k] == n) {
2772 cnt--;
2773 }
2774 }
2775 assert(cnt == 0, "mismatched def-use edge counts");
2776
2777 if (add_to_worklist && !visited.test_set(x->_idx)) {
2778 worklist.push(x);
2779 }
2780 }
2781
2782 if (verify_depth > 0 && list_index == last_index_on_current_depth) {
2783 // All nodes on this depth were processed and its inputs are on the worklist. Decrement verify_depth and
2784 // store the current last list index which is the last node in the list with the new depth. All nodes
2785 // added afterwards will have a new depth again. Stop adding new nodes if depth limit is reached (=0).
2786 verify_depth--;
2787 if (verify_depth == 0) {
2788 add_to_worklist = false;
2789 }
2790 last_index_on_current_depth = worklist.size() - 1;
2791 }
2792 }
2793 }
2794 #endif // not PRODUCT
2795
2796 //------------------------------Registers--------------------------------------
2797 // Do we Match on this edge index or not? Generally false for Control
2798 // and true for everything else. Weird for calls & returns.
2799 uint Node::match_edge(uint idx) const {
2800 return idx; // True for other than index 0 (control)
2801 }
2802
2803 // Register classes are defined for specific machines
2804 const RegMask &Node::out_RegMask() const {
2805 ShouldNotCallThis();
2806 return RegMask::EMPTY;
2807 }
2808
2809 const RegMask &Node::in_RegMask(uint) const {
2810 ShouldNotCallThis();
2811 return RegMask::EMPTY;
2812 }
2813
2814 void Node_Array::grow(uint i) {
2815 assert(i >= _max, "Should have been checked before, use maybe_grow?");
2816 assert(_max > 0, "invariant");
2817 uint old = _max;
2818 _max = next_power_of_2(i);
2819 _nodes = (Node**)_a->Arealloc( _nodes, old*sizeof(Node*),_max*sizeof(Node*));
2820 Copy::zero_to_bytes( &_nodes[old], (_max-old)*sizeof(Node*) );
2821 }
2822
2823 void Node_Array::insert(uint i, Node* n) {
2824 if (_nodes[_max - 1]) {
2825 grow(_max);
2826 }
2827 Copy::conjoint_words_to_higher((HeapWord*)&_nodes[i], (HeapWord*)&_nodes[i + 1], ((_max - i - 1) * sizeof(Node*)));
2828 _nodes[i] = n;
2829 }
2830
2831 void Node_Array::remove(uint i) {
2832 Copy::conjoint_words_to_lower((HeapWord*)&_nodes[i + 1], (HeapWord*)&_nodes[i], ((_max - i - 1) * sizeof(Node*)));
2833 _nodes[_max - 1] = nullptr;
2834 }
2835
2836 void Node_Array::dump() const {
2837 #ifndef PRODUCT
2838 for (uint i = 0; i < _max; i++) {
2839 Node* nn = _nodes[i];
2840 if (nn != nullptr) {
2841 tty->print("%5d--> ",i); nn->dump();
2842 }
2843 }
2844 #endif
2845 }
2846
2847 //--------------------------is_iteratively_computed------------------------------
2848 // Operation appears to be iteratively computed (such as an induction variable)
2849 // It is possible for this operation to return false for a loop-varying
2850 // value, if it appears (by local graph inspection) to be computed by a simple conditional.
2851 bool Node::is_iteratively_computed() {
2852 if (ideal_reg()) { // does operation have a result register?
2853 for (uint i = 1; i < req(); i++) {
2854 Node* n = in(i);
2855 if (n != nullptr && n->is_Phi()) {
2856 for (uint j = 1; j < n->req(); j++) {
2857 if (n->in(j) == this) {
2858 return true;
2859 }
2860 }
2861 }
2862 }
2863 }
2864 return false;
2865 }
2866
2867 //--------------------------find_similar------------------------------
2868 // Return a node with opcode "opc" and same inputs as "this" if one can
2869 // be found; Otherwise return null;
2870 Node* Node::find_similar(int opc) {
2871 if (req() >= 2) {
2872 Node* def = in(1);
2873 if (def && def->outcnt() >= 2) {
2874 for (DUIterator_Fast dmax, i = def->fast_outs(dmax); i < dmax; i++) {
2875 Node* use = def->fast_out(i);
2876 if (use != this &&
2877 use->Opcode() == opc &&
2878 use->req() == req()) {
2879 uint j;
2880 for (j = 0; j < use->req(); j++) {
2881 if (use->in(j) != in(j)) {
2882 break;
2883 }
2884 }
2885 if (j == use->req()) {
2886 return use;
2887 }
2888 }
2889 }
2890 }
2891 }
2892 return nullptr;
2893 }
2894
2895 Node* Node::unique_multiple_edges_out_or_null() const {
2896 Node* use = nullptr;
2897 for (DUIterator_Fast kmax, k = fast_outs(kmax); k < kmax; k++) {
2898 Node* u = fast_out(k);
2899 if (use == nullptr) {
2900 use = u; // first use
2901 } else if (u != use) {
2902 return nullptr; // not unique
2903 } else {
2904 // secondary use
2905 }
2906 }
2907 return use;
2908 }
2909
2910 //--------------------------unique_ctrl_out_or_null-------------------------
2911 // Return the unique control out if only one. Null if none or more than one.
2912 Node* Node::unique_ctrl_out_or_null() const {
2913 Node* found = nullptr;
2914 for (uint i = 0; i < outcnt(); i++) {
2915 Node* use = raw_out(i);
2916 if (use->is_CFG() && use != this) {
2917 if (found != nullptr) {
2918 return nullptr;
2919 }
2920 found = use;
2921 }
2922 }
2923 return found;
2924 }
2925
2926 //--------------------------unique_ctrl_out------------------------------
2927 // Return the unique control out. Asserts if none or more than one control out.
2928 Node* Node::unique_ctrl_out() const {
2929 Node* ctrl = unique_ctrl_out_or_null();
2930 assert(ctrl != nullptr, "control out is assumed to be unique");
2931 return ctrl;
2932 }
2933
2934 void Node::ensure_control_or_add_prec(Node* c) {
2935 if (in(0) == nullptr) {
2936 set_req(0, c);
2937 } else if (in(0) != c) {
2938 add_prec(c);
2939 }
2940 }
2941
2942 void Node::add_prec_from(Node* n) {
2943 for (uint i = n->req(); i < n->len(); i++) {
2944 Node* prec = n->in(i);
2945 if (prec != nullptr) {
2946 add_prec(prec);
2947 }
2948 }
2949 }
2950
2951 bool Node::is_dead_loop_safe() const {
2952 if (is_Phi()) {
2953 return true;
2954 }
2955 if (is_Proj() && in(0) == nullptr) {
2956 return true;
2957 }
2958 if ((_flags & (Flag_is_dead_loop_safe | Flag_is_Con)) != 0) {
2959 if (!is_Proj()) {
2960 return true;
2961 }
2962 if (in(0)->is_Allocate()) {
2963 return false;
2964 }
2965 // MemNode::can_see_stored_value() peeks through the boxing call
2966 if (in(0)->is_CallStaticJava() && in(0)->as_CallStaticJava()->is_boxing_method()) {
2967 return false;
2968 }
2969 return true;
2970 }
2971 return false;
2972 }
2973
2974 bool Node::is_div_or_mod(BasicType bt) const { return Opcode() == Op_Div(bt) || Opcode() == Op_Mod(bt) ||
2975 Opcode() == Op_UDiv(bt) || Opcode() == Op_UMod(bt); }
2976
2977 // `maybe_pure_function` is assumed to be the input of `this`. This is a bit redundant,
2978 // but we already have and need maybe_pure_function in all the call sites, so
2979 // it makes it obvious that the `maybe_pure_function` is the same node as in the caller,
2980 // while it takes more thinking to realize that a locally computed in(0) must be equal to
2981 // the local in the caller.
2982 bool Node::is_data_proj_of_pure_function(const Node* maybe_pure_function) const {
2983 return Opcode() == Op_Proj && as_Proj()->_con == TypeFunc::Parms && maybe_pure_function->is_CallLeafPure();
2984 }
2985
2986 //=============================================================================
2987 //------------------------------yank-------------------------------------------
2988 // Find and remove
2989 void Node_List::yank( Node *n ) {
2990 uint i;
2991 for (i = 0; i < _cnt; i++) {
2992 if (_nodes[i] == n) {
2993 break;
2994 }
2995 }
2996
2997 if (i < _cnt) {
2998 _nodes[i] = _nodes[--_cnt];
2999 }
3000 }
3001
3002 //------------------------------dump-------------------------------------------
3003 void Node_List::dump() const {
3004 #ifndef PRODUCT
3005 for (uint i = 0; i < _cnt; i++) {
3006 if (_nodes[i]) {
3007 tty->print("%5d--> ", i);
3008 _nodes[i]->dump();
3009 }
3010 }
3011 #endif
3012 }
3013
3014 void Node_List::dump_simple() const {
3015 #ifndef PRODUCT
3016 for (uint i = 0; i < _cnt; i++) {
3017 if( _nodes[i] ) {
3018 tty->print(" %d", _nodes[i]->_idx);
3019 } else {
3020 tty->print(" null");
3021 }
3022 }
3023 #endif
3024 }
3025
3026 //=============================================================================
3027 //------------------------------remove-----------------------------------------
3028 void Unique_Node_List::remove(Node* n) {
3029 if (_in_worklist.test(n->_idx)) {
3030 for (uint i = 0; i < size(); i++) {
3031 if (_nodes[i] == n) {
3032 map(i, Node_List::pop());
3033 _in_worklist.remove(n->_idx);
3034 return;
3035 }
3036 }
3037 ShouldNotReachHere();
3038 }
3039 }
3040
3041 //-----------------------remove_useless_nodes----------------------------------
3042 // Remove useless nodes from worklist
3043 void Unique_Node_List::remove_useless_nodes(VectorSet &useful) {
3044 for (uint i = 0; i < size(); ++i) {
3045 Node *n = at(i);
3046 assert( n != nullptr, "Did not expect null entries in worklist");
3047 if (!useful.test(n->_idx)) {
3048 _in_worklist.remove(n->_idx);
3049 map(i, Node_List::pop());
3050 --i; // Visit popped node
3051 // If it was last entry, loop terminates since size() was also reduced
3052 }
3053 }
3054 }
3055
3056 //=============================================================================
3057 void Node_Stack::grow() {
3058 size_t old_top = pointer_delta(_inode_top,_inodes,sizeof(INode)); // save _top
3059 size_t old_max = pointer_delta(_inode_max,_inodes,sizeof(INode));
3060 size_t max = old_max << 1; // max * 2
3061 _inodes = REALLOC_ARENA_ARRAY(_a, INode, _inodes, old_max, max);
3062 _inode_max = _inodes + max;
3063 _inode_top = _inodes + old_top; // restore _top
3064 }
3065
3066 // Node_Stack is used to map nodes.
3067 Node* Node_Stack::find(uint idx) const {
3068 uint sz = size();
3069 for (uint i = 0; i < sz; i++) {
3070 if (idx == index_at(i)) {
3071 return node_at(i);
3072 }
3073 }
3074 return nullptr;
3075 }
3076
3077 //=============================================================================
3078 uint TypeNode::size_of() const { return sizeof(*this); }
3079 #ifndef PRODUCT
3080 void TypeNode::dump_spec(outputStream *st) const {
3081 if (!Verbose && !WizardMode) {
3082 // standard dump does this in Verbose and WizardMode
3083 st->print(" #"); _type->dump_on(st);
3084 }
3085 }
3086
3087 void TypeNode::dump_compact_spec(outputStream *st) const {
3088 st->print("#");
3089 _type->dump_on(st);
3090 }
3091 #endif
3092 uint TypeNode::hash() const {
3093 return Node::hash() + _type->hash();
3094 }
3095 bool TypeNode::cmp(const Node& n) const {
3096 return Type::equals(_type, n.as_Type()->_type);
3097 }
3098 const Type* TypeNode::bottom_type() const { return _type; }
3099 const Type* TypeNode::Value(PhaseGVN* phase) const { return _type; }
3100
3101 //------------------------------ideal_reg--------------------------------------
3102 uint TypeNode::ideal_reg() const {
3103 return _type->ideal_reg();
3104 }
3105
3106 void TypeNode::make_path_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, Node* ctrl_use, uint j, const char* phase_str) {
3107 Node* c = ctrl_use->in(j);
3108 if (igvn->type(c) != Type::TOP) {
3109 igvn->replace_input_of(ctrl_use, j, igvn->C->top());
3110 create_halt_path(igvn, c, loop, phase_str);
3111 }
3112 }
3113
3114 // This Type node is dead. It could be because the type that it captures and the type of the node computed from its
3115 // inputs do not intersect anymore. That node has some uses along some control flow paths. Those control flow paths must
3116 // be unreachable as using a dead value makes no sense. For the Type node to capture a narrowed down type, some control
3117 // flow construct must guard the Type node (an If node usually). When the Type node becomes dead, the guard usually
3118 // constant folds and the control flow that leads to the Type node becomes unreachable. There are cases where that
3119 // doesn't happen, however. They are handled here by following uses of the Type node until a CFG or a Phi to find dead
3120 // paths. The dead paths are then replaced by a Halt node.
3121 void TypeNode::make_paths_from_here_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, const char* phase_str) {
3122 Unique_Node_List wq;
3123 wq.push(this);
3124 for (uint i = 0; i < wq.size(); ++i) {
3125 Node* n = wq.at(i);
3126 for (DUIterator_Fast kmax, k = n->fast_outs(kmax); k < kmax; k++) {
3127 Node* u = n->fast_out(k);
3128 if (u->is_CFG()) {
3129 assert(!u->is_Region(), "Can't reach a Region without going through a Phi");
3130 make_path_dead(igvn, loop, u, 0, phase_str);
3131 } else if (u->is_Phi()) {
3132 Node* r = u->in(0);
3133 assert(r->is_Region() || r->is_top(), "unexpected Phi's control");
3134 if (r->is_Region()) {
3135 for (uint j = 1; j < u->req(); ++j) {
3136 if (u->in(j) == n && r->in(j) != nullptr) {
3137 make_path_dead(igvn, loop, r, j, phase_str);
3138 }
3139 }
3140 }
3141 } else {
3142 wq.push(u);
3143 }
3144 }
3145 }
3146 }
3147
3148 void TypeNode::create_halt_path(PhaseIterGVN* igvn, Node* c, PhaseIdealLoop* loop, const char* phase_str) const {
3149 Node* frame = new ParmNode(igvn->C->start(), TypeFunc::FramePtr);
3150 if (loop == nullptr) {
3151 igvn->register_new_node_with_optimizer(frame);
3152 } else {
3153 loop->register_new_node(frame, igvn->C->start());
3154 }
3155
3156 stringStream ss;
3157 ss.print("dead path discovered by TypeNode during %s", phase_str);
3158
3159 Node* halt = new HaltNode(c, frame, ss.as_string(igvn->C->comp_arena()));
3160 if (loop == nullptr) {
3161 igvn->register_new_node_with_optimizer(halt);
3162 } else {
3163 loop->register_control(halt, loop->ltree_root(), c);
3164 }
3165 igvn->add_input_to(igvn->C->root(), halt);
3166 }
3167
3168 Node* TypeNode::Ideal(PhaseGVN* phase, bool can_reshape) {
3169 if (KillPathsReachableByDeadTypeNode && can_reshape && Value(phase) == Type::TOP) {
3170 PhaseIterGVN* igvn = phase->is_IterGVN();
3171 Node* top = igvn->C->top();
3172 ResourceMark rm;
3173 make_paths_from_here_dead(igvn, nullptr, "igvn");
3174 return top;
3175 }
3176
3177 return Node::Ideal(phase, can_reshape);
3178 }
3179