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