1 /*
2 * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2024, 2025, Alibaba Group Holding Limited. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "gc/shared/barrierSet.hpp"
27 #include "gc/shared/c2/barrierSetC2.hpp"
28 #include "libadt/vectset.hpp"
29 #include "memory/allocation.inline.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "opto/ad.hpp"
32 #include "opto/callGenerator.hpp"
33 #include "opto/castnode.hpp"
34 #include "opto/cfgnode.hpp"
35 #include "opto/connode.hpp"
36 #include "opto/loopnode.hpp"
37 #include "opto/machnode.hpp"
38 #include "opto/matcher.hpp"
39 #include "opto/node.hpp"
40 #include "opto/opcodes.hpp"
41 #include "opto/regmask.hpp"
42 #include "opto/rootnode.hpp"
43 #include "opto/type.hpp"
44 #include "utilities/copy.hpp"
45 #include "utilities/macros.hpp"
46 #include "utilities/powerOfTwo.hpp"
47 #include "utilities/stringUtils.hpp"
48
49 class RegMask;
50 // #include "phase.hpp"
51 class PhaseTransform;
52 class PhaseGVN;
53
54 // Arena we are currently building Nodes in
55 const uint Node::NotAMachineReg = 0xffff0000;
56
57 #ifndef PRODUCT
58 extern uint nodes_created;
59 #endif
60 #ifdef __clang__
61 #pragma clang diagnostic push
62 #pragma GCC diagnostic ignored "-Wuninitialized"
63 #endif
64
65 #ifdef ASSERT
66
67 //-------------------------- construct_node------------------------------------
68 // Set a breakpoint here to identify where a particular node index is built.
69 void Node::verify_construction() {
70 _debug_orig = nullptr;
71 // The decimal digits of _debug_idx are <compile_id> followed by 10 digits of <_idx>
72 Compile* C = Compile::current();
73 assert(C->unique() < (INT_MAX - 1), "Node limit exceeded INT_MAX");
74 uint64_t new_debug_idx = (uint64_t)C->compile_id() * 10000000000 + _idx;
75 set_debug_idx(new_debug_idx);
76 if (!C->phase_optimize_finished()) {
77 // Only check assert during parsing and optimization phase. Skip it while generating code.
78 assert(C->live_nodes() <= C->max_node_limit(), "Live Node limit exceeded limit");
79 }
80 if (BreakAtNode != 0 && (_debug_idx == BreakAtNode || (uint64_t)_idx == BreakAtNode)) {
81 tty->print_cr("BreakAtNode: _idx=%d _debug_idx=" UINT64_FORMAT, _idx, _debug_idx);
82 BREAKPOINT;
83 }
84 #if OPTO_DU_ITERATOR_ASSERT
85 _last_del = nullptr;
86 _del_tick = 0;
87 #endif
88 _hash_lock = 0;
89 }
90
91
92 // #ifdef ASSERT ...
93
94 #if OPTO_DU_ITERATOR_ASSERT
95 void DUIterator_Common::sample(const Node* node) {
96 _vdui = VerifyDUIterators;
97 _node = node;
98 _outcnt = node->_outcnt;
99 _del_tick = node->_del_tick;
100 _last = nullptr;
101 }
102
103 void DUIterator_Common::verify(const Node* node, bool at_end_ok) {
104 assert(_node == node, "consistent iterator source");
105 assert(_del_tick == node->_del_tick, "no unexpected deletions allowed");
106 }
107
108 void DUIterator_Common::verify_resync() {
109 // Ensure that the loop body has just deleted the last guy produced.
110 const Node* node = _node;
111 // Ensure that at least one copy of the last-seen edge was deleted.
112 // Note: It is OK to delete multiple copies of the last-seen edge.
113 // Unfortunately, we have no way to verify that all the deletions delete
114 // that same edge. On this point we must use the Honor System.
115 assert(node->_del_tick >= _del_tick+1, "must have deleted an edge");
116 assert(node->_last_del == _last, "must have deleted the edge just produced");
117 // We liked this deletion, so accept the resulting outcnt and tick.
118 _outcnt = node->_outcnt;
119 _del_tick = node->_del_tick;
120 }
121
122 void DUIterator_Common::reset(const DUIterator_Common& that) {
123 if (this == &that) return; // ignore assignment to self
124 if (!_vdui) {
125 // We need to initialize everything, overwriting garbage values.
126 _last = that._last;
127 _vdui = that._vdui;
128 }
129 // Note: It is legal (though odd) for an iterator over some node x
130 // to be reassigned to iterate over another node y. Some doubly-nested
131 // progress loops depend on being able to do this.
132 const Node* node = that._node;
133 // Re-initialize everything, except _last.
134 _node = node;
135 _outcnt = node->_outcnt;
136 _del_tick = node->_del_tick;
137 }
138
139 void DUIterator::sample(const Node* node) {
140 DUIterator_Common::sample(node); // Initialize the assertion data.
141 _refresh_tick = 0; // No refreshes have happened, as yet.
142 }
143
144 void DUIterator::verify(const Node* node, bool at_end_ok) {
145 DUIterator_Common::verify(node, at_end_ok);
146 assert(_idx < node->_outcnt + (uint)at_end_ok, "idx in range");
147 }
148
149 void DUIterator::verify_increment() {
150 if (_refresh_tick & 1) {
151 // We have refreshed the index during this loop.
152 // Fix up _idx to meet asserts.
153 if (_idx > _outcnt) _idx = _outcnt;
154 }
155 verify(_node, true);
156 }
157
158 void DUIterator::verify_resync() {
159 // Note: We do not assert on _outcnt, because insertions are OK here.
160 DUIterator_Common::verify_resync();
161 // Make sure we are still in sync, possibly with no more out-edges:
162 verify(_node, true);
163 }
164
165 void DUIterator::reset(const DUIterator& that) {
166 if (this == &that) return; // self assignment is always a no-op
167 assert(that._refresh_tick == 0, "assign only the result of Node::outs()");
168 assert(that._idx == 0, "assign only the result of Node::outs()");
169 assert(_idx == that._idx, "already assigned _idx");
170 if (!_vdui) {
171 // We need to initialize everything, overwriting garbage values.
172 sample(that._node);
173 } else {
174 DUIterator_Common::reset(that);
175 if (_refresh_tick & 1) {
176 _refresh_tick++; // Clear the "was refreshed" flag.
177 }
178 assert(_refresh_tick < 2*100000, "DU iteration must converge quickly");
179 }
180 }
181
182 void DUIterator::refresh() {
183 DUIterator_Common::sample(_node); // Re-fetch assertion data.
184 _refresh_tick |= 1; // Set the "was refreshed" flag.
185 }
186
187 void DUIterator::verify_finish() {
188 // If the loop has killed the node, do not require it to re-run.
189 if (_node->_outcnt == 0) _refresh_tick &= ~1;
190 // If this assert triggers, it means that a loop used refresh_out_pos
191 // to re-synch an iteration index, but the loop did not correctly
192 // re-run itself, using a "while (progress)" construct.
193 // This iterator enforces the rule that you must keep trying the loop
194 // until it "runs clean" without any need for refreshing.
195 assert(!(_refresh_tick & 1), "the loop must run once with no refreshing");
196 }
197
198
199 void DUIterator_Fast::verify(const Node* node, bool at_end_ok) {
200 DUIterator_Common::verify(node, at_end_ok);
201 Node** out = node->_out;
202 uint cnt = node->_outcnt;
203 assert(cnt == _outcnt, "no insertions allowed");
204 assert(_outp >= out && _outp <= out + cnt - !at_end_ok, "outp in range");
205 // This last check is carefully designed to work for NO_OUT_ARRAY.
206 }
207
208 void DUIterator_Fast::verify_limit() {
209 const Node* node = _node;
210 verify(node, true);
211 assert(_outp == node->_out + node->_outcnt, "limit still correct");
212 }
213
214 void DUIterator_Fast::verify_resync() {
215 const Node* node = _node;
216 if (_outp == node->_out + _outcnt) {
217 // Note that the limit imax, not the pointer i, gets updated with the
218 // exact count of deletions. (For the pointer it's always "--i".)
219 assert(node->_outcnt+node->_del_tick == _outcnt+_del_tick, "no insertions allowed with deletion(s)");
220 // This is a limit pointer, with a name like "imax".
221 // Fudge the _last field so that the common assert will be happy.
222 _last = (Node*) node->_last_del;
223 DUIterator_Common::verify_resync();
224 } else {
225 assert(node->_outcnt < _outcnt, "no insertions allowed with deletion(s)");
226 // A normal internal pointer.
227 DUIterator_Common::verify_resync();
228 // Make sure we are still in sync, possibly with no more out-edges:
229 verify(node, true);
230 }
231 }
232
233 void DUIterator_Fast::verify_relimit(uint n) {
234 const Node* node = _node;
235 assert((int)n > 0, "use imax -= n only with a positive count");
236 // This must be a limit pointer, with a name like "imax".
237 assert(_outp == node->_out + node->_outcnt, "apply -= only to a limit (imax)");
238 // The reported number of deletions must match what the node saw.
239 assert(node->_del_tick == _del_tick + n, "must have deleted n edges");
240 // Fudge the _last field so that the common assert will be happy.
241 _last = (Node*) node->_last_del;
242 DUIterator_Common::verify_resync();
243 }
244
245 void DUIterator_Fast::reset(const DUIterator_Fast& that) {
246 assert(_outp == that._outp, "already assigned _outp");
247 DUIterator_Common::reset(that);
248 }
249
250 void DUIterator_Last::verify(const Node* node, bool at_end_ok) {
251 // at_end_ok means the _outp is allowed to underflow by 1
252 _outp += at_end_ok;
253 DUIterator_Fast::verify(node, at_end_ok); // check _del_tick, etc.
254 _outp -= at_end_ok;
255 assert(_outp == (node->_out + node->_outcnt) - 1, "pointer must point to end of nodes");
256 }
257
258 void DUIterator_Last::verify_limit() {
259 // Do not require the limit address to be resynched.
260 //verify(node, true);
261 assert(_outp == _node->_out, "limit still correct");
262 }
263
264 void DUIterator_Last::verify_step(uint num_edges) {
265 assert((int)num_edges > 0, "need non-zero edge count for loop progress");
266 _outcnt -= num_edges;
267 _del_tick += num_edges;
268 // Make sure we are still in sync, possibly with no more out-edges:
269 const Node* node = _node;
270 verify(node, true);
271 assert(node->_last_del == _last, "must have deleted the edge just produced");
272 }
273
274 #endif //OPTO_DU_ITERATOR_ASSERT
275
276
277 #endif //ASSERT
278
279
280 // This constant used to initialize _out may be any non-null value.
281 // The value null is reserved for the top node only.
282 #define NO_OUT_ARRAY ((Node**)-1)
283
284 // Out-of-line code from node constructors.
285 // Executed only when extra debug info. is being passed around.
286 static void init_node_notes(Compile* C, int idx, Node_Notes* nn) {
287 C->set_node_notes_at(idx, nn);
288 }
289
290 // Shared initialization code.
291 inline int Node::Init(int req) {
292 Compile* C = Compile::current();
293 int idx = C->next_unique();
294 NOT_PRODUCT(_igv_idx = C->next_igv_idx());
295
296 // Allocate memory for the necessary number of edges.
297 if (req > 0) {
298 // Allocate space for _in array to have double alignment.
299 _in = (Node **) ((char *) (C->node_arena()->AmallocWords(req * sizeof(void*))));
300 }
301 // If there are default notes floating around, capture them:
302 Node_Notes* nn = C->default_node_notes();
303 if (nn != nullptr) init_node_notes(C, idx, nn);
304
305 // Note: At this point, C is dead,
306 // and we begin to initialize the new Node.
307
308 _cnt = _max = req;
309 _outcnt = _outmax = 0;
310 _class_id = Class_Node;
311 _flags = 0;
312 _out = NO_OUT_ARRAY;
313 return idx;
314 }
315
316 //------------------------------Node-------------------------------------------
317 // Create a Node, with a given number of required edges.
318 Node::Node(uint req)
319 : _idx(Init(req))
320 #ifdef ASSERT
321 , _parse_idx(_idx)
322 #endif
323 {
324 assert( req < Compile::current()->max_node_limit() - NodeLimitFudgeFactor, "Input limit exceeded" );
325 DEBUG_ONLY( verify_construction() );
326 NOT_PRODUCT(nodes_created++);
327 if (req == 0) {
328 _in = nullptr;
329 } else {
330 Node** to = _in;
331 for(uint i = 0; i < req; i++) {
332 to[i] = nullptr;
333 }
334 }
335 }
336
337 //------------------------------Node-------------------------------------------
338 Node::Node(Node *n0)
339 : _idx(Init(1))
340 #ifdef ASSERT
341 , _parse_idx(_idx)
342 #endif
343 {
344 DEBUG_ONLY( verify_construction() );
345 NOT_PRODUCT(nodes_created++);
346 assert( is_not_dead(n0), "can not use dead node");
347 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
348 }
349
350 //------------------------------Node-------------------------------------------
351 Node::Node(Node *n0, Node *n1)
352 : _idx(Init(2))
353 #ifdef ASSERT
354 , _parse_idx(_idx)
355 #endif
356 {
357 DEBUG_ONLY( verify_construction() );
358 NOT_PRODUCT(nodes_created++);
359 assert( is_not_dead(n0), "can not use dead node");
360 assert( is_not_dead(n1), "can not use dead node");
361 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
362 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
363 }
364
365 //------------------------------Node-------------------------------------------
366 Node::Node(Node *n0, Node *n1, Node *n2)
367 : _idx(Init(3))
368 #ifdef ASSERT
369 , _parse_idx(_idx)
370 #endif
371 {
372 DEBUG_ONLY( verify_construction() );
373 NOT_PRODUCT(nodes_created++);
374 assert( is_not_dead(n0), "can not use dead node");
375 assert( is_not_dead(n1), "can not use dead node");
376 assert( is_not_dead(n2), "can not use dead node");
377 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
378 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
379 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
380 }
381
382 //------------------------------Node-------------------------------------------
383 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3)
384 : _idx(Init(4))
385 #ifdef ASSERT
386 , _parse_idx(_idx)
387 #endif
388 {
389 DEBUG_ONLY( verify_construction() );
390 NOT_PRODUCT(nodes_created++);
391 assert( is_not_dead(n0), "can not use dead node");
392 assert( is_not_dead(n1), "can not use dead node");
393 assert( is_not_dead(n2), "can not use dead node");
394 assert( is_not_dead(n3), "can not use dead node");
395 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
396 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
397 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
398 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
399 }
400
401 //------------------------------Node-------------------------------------------
402 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3, Node *n4)
403 : _idx(Init(5))
404 #ifdef ASSERT
405 , _parse_idx(_idx)
406 #endif
407 {
408 DEBUG_ONLY( verify_construction() );
409 NOT_PRODUCT(nodes_created++);
410 assert( is_not_dead(n0), "can not use dead node");
411 assert( is_not_dead(n1), "can not use dead node");
412 assert( is_not_dead(n2), "can not use dead node");
413 assert( is_not_dead(n3), "can not use dead node");
414 assert( is_not_dead(n4), "can not use dead node");
415 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
416 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
417 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
418 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
419 _in[4] = n4; if (n4 != nullptr) n4->add_out((Node *)this);
420 }
421
422 //------------------------------Node-------------------------------------------
423 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
424 Node *n4, Node *n5)
425 : _idx(Init(6))
426 #ifdef ASSERT
427 , _parse_idx(_idx)
428 #endif
429 {
430 DEBUG_ONLY( verify_construction() );
431 NOT_PRODUCT(nodes_created++);
432 assert( is_not_dead(n0), "can not use dead node");
433 assert( is_not_dead(n1), "can not use dead node");
434 assert( is_not_dead(n2), "can not use dead node");
435 assert( is_not_dead(n3), "can not use dead node");
436 assert( is_not_dead(n4), "can not use dead node");
437 assert( is_not_dead(n5), "can not use dead node");
438 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
439 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
440 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
441 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
442 _in[4] = n4; if (n4 != nullptr) n4->add_out((Node *)this);
443 _in[5] = n5; if (n5 != nullptr) n5->add_out((Node *)this);
444 }
445
446 //------------------------------Node-------------------------------------------
447 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
448 Node *n4, Node *n5, Node *n6)
449 : _idx(Init(7))
450 #ifdef ASSERT
451 , _parse_idx(_idx)
452 #endif
453 {
454 DEBUG_ONLY( verify_construction() );
455 NOT_PRODUCT(nodes_created++);
456 assert( is_not_dead(n0), "can not use dead node");
457 assert( is_not_dead(n1), "can not use dead node");
458 assert( is_not_dead(n2), "can not use dead node");
459 assert( is_not_dead(n3), "can not use dead node");
460 assert( is_not_dead(n4), "can not use dead node");
461 assert( is_not_dead(n5), "can not use dead node");
462 assert( is_not_dead(n6), "can not use dead node");
463 _in[0] = n0; if (n0 != nullptr) n0->add_out((Node *)this);
464 _in[1] = n1; if (n1 != nullptr) n1->add_out((Node *)this);
465 _in[2] = n2; if (n2 != nullptr) n2->add_out((Node *)this);
466 _in[3] = n3; if (n3 != nullptr) n3->add_out((Node *)this);
467 _in[4] = n4; if (n4 != nullptr) n4->add_out((Node *)this);
468 _in[5] = n5; if (n5 != nullptr) n5->add_out((Node *)this);
469 _in[6] = n6; if (n6 != nullptr) n6->add_out((Node *)this);
470 }
471
472 #ifdef __clang__
473 #pragma clang diagnostic pop
474 #endif
475
476
477 //------------------------------clone------------------------------------------
478 // Clone a Node.
479 Node *Node::clone() const {
480 Compile* C = Compile::current();
481 uint s = size_of(); // Size of inherited Node
482 Node *n = (Node*)C->node_arena()->AmallocWords(size_of() + _max*sizeof(Node*));
483 Copy::conjoint_words_to_lower((HeapWord*)this, (HeapWord*)n, s);
484 // Set the new input pointer array
485 n->_in = (Node**)(((char*)n)+s);
486 // Cannot share the old output pointer array, so kill it
487 n->_out = NO_OUT_ARRAY;
488 // And reset the counters to 0
489 n->_outcnt = 0;
490 n->_outmax = 0;
491 // Unlock this guy, since he is not in any hash table.
492 DEBUG_ONLY(n->_hash_lock = 0);
493 // Walk the old node's input list to duplicate its edges
494 uint i;
495 for( i = 0; i < len(); i++ ) {
496 Node *x = in(i);
497 n->_in[i] = x;
498 if (x != nullptr) x->add_out(n);
499 }
500 if (is_macro()) {
501 C->add_macro_node(n);
502 }
503 if (is_expensive()) {
504 C->add_expensive_node(n);
505 }
506 if (for_post_loop_opts_igvn()) {
507 // Don't add cloned node to Compile::_for_post_loop_opts_igvn list automatically.
508 // If it is applicable, it will happen anyway when the cloned node is registered with IGVN.
509 n->remove_flag(Node::NodeFlags::Flag_for_post_loop_opts_igvn);
510 }
511 if (for_merge_stores_igvn()) {
512 // Don't add cloned node to Compile::_for_merge_stores_igvn list automatically.
513 // If it is applicable, it will happen anyway when the cloned node is registered with IGVN.
514 n->remove_flag(Node::NodeFlags::Flag_for_merge_stores_igvn);
515 }
516 if (n->is_ParsePredicate()) {
517 C->add_parse_predicate(n->as_ParsePredicate());
518 }
519 if (n->is_OpaqueTemplateAssertionPredicate()) {
520 C->add_template_assertion_predicate_opaque(n->as_OpaqueTemplateAssertionPredicate());
521 }
522
523 n->set_idx(C->next_unique()); // Get new unique index as well
524 NOT_PRODUCT(n->_igv_idx = C->next_igv_idx());
525 DEBUG_ONLY( n->verify_construction() );
526 NOT_PRODUCT(nodes_created++);
527 // Do not patch over the debug_idx of a clone, because it makes it
528 // impossible to break on the clone's moment of creation.
529 //DEBUG_ONLY( n->set_debug_idx( debug_idx() ) );
530
531 C->copy_node_notes_to(n, (Node*) this);
532
533 // MachNode clone
534 uint nopnds;
535 if (this->is_Mach() && (nopnds = this->as_Mach()->num_opnds()) > 0) {
536 MachNode *mach = n->as_Mach();
537 MachNode *mthis = this->as_Mach();
538 // Get address of _opnd_array.
539 // It should be the same offset since it is the clone of this node.
540 MachOper **from = mthis->_opnds;
541 MachOper **to = (MachOper **)((size_t)(&mach->_opnds) +
542 pointer_delta((const void*)from,
543 (const void*)(&mthis->_opnds), 1));
544 mach->_opnds = to;
545 for ( uint i = 0; i < nopnds; ++i ) {
546 to[i] = from[i]->clone();
547 }
548 }
549 if (this->is_MachProj()) {
550 // MachProjNodes contain register masks that may contain pointers to
551 // externally allocated memory. Make sure to use a proper constructor
552 // instead of just shallowly copying.
553 MachProjNode* mach = n->as_MachProj();
554 MachProjNode* mthis = this->as_MachProj();
555 new (&mach->_rout) RegMask(mthis->_rout);
556 }
557 if (n->is_Call()) {
558 // CallGenerator is linked to the original node.
559 CallGenerator* cg = n->as_Call()->generator();
560 if (cg != nullptr) {
561 CallGenerator* cloned_cg = cg->with_call_node(n->as_Call());
562 n->as_Call()->set_generator(cloned_cg);
563 }
564 }
565 if (n->is_SafePoint()) {
566 // Scalar replacement and macro expansion might modify the JVMState.
567 // Clone it to make sure it's not shared between SafePointNodes.
568 n->as_SafePoint()->clone_jvms(C);
569 n->as_SafePoint()->clone_replaced_nodes();
570 }
571 Compile::current()->record_modified_node(n);
572 return n; // Return the clone
573 }
574
575 //---------------------------setup_is_top--------------------------------------
576 // Call this when changing the top node, to reassert the invariants
577 // required by Node::is_top. See Compile::set_cached_top_node.
578 void Node::setup_is_top() {
579 if (this == (Node*)Compile::current()->top()) {
580 // This node has just become top. Kill its out array.
581 _outcnt = _outmax = 0;
582 _out = nullptr; // marker value for top
583 assert(is_top(), "must be top");
584 } else {
585 if (_out == nullptr) _out = NO_OUT_ARRAY;
586 assert(!is_top(), "must not be top");
587 }
588 }
589
590 //------------------------------~Node------------------------------------------
591 // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
592 void Node::destruct(PhaseValues* phase) {
593 Compile* compile = (phase != nullptr) ? phase->C : Compile::current();
594 if (phase != nullptr && phase->is_IterGVN()) {
595 phase->is_IterGVN()->_worklist.remove(this);
596 }
597 // If this is the most recently created node, reclaim its index. Otherwise,
598 // record the node as dead to keep liveness information accurate.
599 if ((uint)_idx+1 == compile->unique()) {
600 compile->set_unique(compile->unique()-1);
601 } else {
602 compile->record_dead_node(_idx);
603 }
604 // Clear debug info:
605 Node_Notes* nn = compile->node_notes_at(_idx);
606 if (nn != nullptr) nn->clear();
607 // Walk the input array, freeing the corresponding output edges
608 _cnt = _max; // forget req/prec distinction
609 uint i;
610 for( i = 0; i < _max; i++ ) {
611 set_req(i, nullptr);
612 //assert(def->out(def->outcnt()-1) == (Node *)this,"bad def-use hacking in reclaim");
613 }
614 assert(outcnt() == 0, "deleting a node must not leave a dangling use");
615
616 if (is_macro()) {
617 compile->remove_macro_node(this);
618 }
619 if (is_expensive()) {
620 compile->remove_expensive_node(this);
621 }
622 if (is_OpaqueTemplateAssertionPredicate()) {
623 compile->remove_template_assertion_predicate_opaque(as_OpaqueTemplateAssertionPredicate());
624 }
625 if (is_ParsePredicate()) {
626 compile->remove_parse_predicate(as_ParsePredicate());
627 }
628 if (for_post_loop_opts_igvn()) {
629 compile->remove_from_post_loop_opts_igvn(this);
630 }
631 if (for_merge_stores_igvn()) {
632 compile->remove_from_merge_stores_igvn(this);
633 }
634
635 if (is_SafePoint()) {
636 as_SafePoint()->delete_replaced_nodes();
637
638 if (is_CallStaticJava()) {
639 compile->remove_unstable_if_trap(as_CallStaticJava(), false);
640 }
641 }
642
643 // See if the input array was allocated just prior to the object
644 int edge_size = _max*sizeof(void*);
645 int out_edge_size = _outmax*sizeof(void*);
646 char *in_array = ((char*)_in);
647 char *edge_end = in_array + edge_size;
648 char *out_array = (char*)(_out == NO_OUT_ARRAY? nullptr: _out);
649 int node_size = size_of();
650
651 #ifdef ASSERT
652 // We will not actually delete the storage, but we'll make the node unusable.
653 compile->remove_modified_node(this);
654 *(address*)this = badAddress; // smash the C++ vtbl, probably
655 _in = _out = (Node**) badAddress;
656 _max = _cnt = _outmax = _outcnt = 0;
657 #endif
658
659 // Free the output edge array
660 if (out_edge_size > 0) {
661 compile->node_arena()->Afree(out_array, out_edge_size);
662 }
663
664 // Free the input edge array and the node itself
665 if( edge_end == (char*)this ) {
666 // It was; free the input array and object all in one hit
667 #ifndef ASSERT
668 compile->node_arena()->Afree(in_array, edge_size+node_size);
669 #endif
670 } else {
671 // Free just the input array
672 compile->node_arena()->Afree(in_array, edge_size);
673
674 // Free just the object
675 #ifndef ASSERT
676 compile->node_arena()->Afree(this, node_size);
677 #endif
678 }
679 }
680
681 // Resize input or output array to grow it to the next larger power-of-2 bigger
682 // than len.
683 void Node::resize_array(Node**& array, node_idx_t& max_size, uint len, bool needs_clearing) {
684 Arena* arena = Compile::current()->node_arena();
685 uint new_max = max_size;
686 if (new_max == 0) {
687 max_size = 4;
688 array = (Node**)arena->Amalloc(4 * sizeof(Node*));
689 if (needs_clearing) {
690 array[0] = nullptr;
691 array[1] = nullptr;
692 array[2] = nullptr;
693 array[3] = nullptr;
694 }
695 return;
696 }
697 new_max = next_power_of_2(len);
698 assert(needs_clearing || (array != nullptr && array != NO_OUT_ARRAY), "out must have sensible value");
699 array = (Node**)arena->Arealloc(array, max_size * sizeof(Node*), new_max * sizeof(Node*));
700 if (needs_clearing) {
701 Copy::zero_to_bytes(&array[max_size], (new_max - max_size) * sizeof(Node*)); // null all new space
702 }
703 max_size = new_max; // Record new max length
704 // This assertion makes sure that Node::_max is wide enough to
705 // represent the numerical value of new_max.
706 assert(max_size > len, "int width of _max or _outmax is too small");
707 }
708
709 //------------------------------grow-------------------------------------------
710 // Grow the input array, making space for more edges
711 void Node::grow(uint len) {
712 resize_array(_in, _max, len, true);
713 }
714
715 //-----------------------------out_grow----------------------------------------
716 // Grow the input array, making space for more edges
717 void Node::out_grow(uint len) {
718 assert(!is_top(), "cannot grow a top node's out array");
719 resize_array(_out, _outmax, len, false);
720 }
721
722 #ifdef ASSERT
723 //------------------------------is_dead----------------------------------------
724 bool Node::is_dead() const {
725 // Mach and pinch point nodes may look like dead.
726 if( is_top() || is_Mach() || (Opcode() == Op_Node && _outcnt > 0) )
727 return false;
728 for( uint i = 0; i < _max; i++ )
729 if( _in[i] != nullptr )
730 return false;
731 return true;
732 }
733
734 bool Node::is_not_dead(const Node* n) {
735 return n == nullptr || !PhaseIterGVN::is_verify_def_use() || !(n->is_dead());
736 }
737
738 bool Node::is_reachable_from_root() const {
739 ResourceMark rm;
740 Unique_Node_List wq;
741 wq.push((Node*)this);
742 RootNode* root = Compile::current()->root();
743 for (uint i = 0; i < wq.size(); i++) {
744 Node* m = wq.at(i);
745 if (m == root) {
746 return true;
747 }
748 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) {
749 Node* u = m->fast_out(j);
750 wq.push(u);
751 }
752 }
753 return false;
754 }
755 #endif
756
757 //------------------------------is_unreachable---------------------------------
758 bool Node::is_unreachable(PhaseIterGVN &igvn) const {
759 assert(!is_Mach(), "doesn't work with MachNodes");
760 return outcnt() == 0 || igvn.type(this) == Type::TOP || (in(0) != nullptr && in(0)->is_top());
761 }
762
763 //------------------------------add_req----------------------------------------
764 // Add a new required input at the end
765 void Node::add_req( Node *n ) {
766 assert( is_not_dead(n), "can not use dead node");
767
768 // Look to see if I can move precedence down one without reallocating
769 if( (_cnt >= _max) || (in(_max-1) != nullptr) )
770 grow( _max+1 );
771
772 // Find a precedence edge to move
773 if( in(_cnt) != nullptr ) { // Next precedence edge is busy?
774 uint i;
775 for( i=_cnt; i<_max; i++ )
776 if( in(i) == nullptr ) // Find the null at end of prec edge list
777 break; // There must be one, since we grew the array
778 _in[i] = in(_cnt); // Move prec over, making space for req edge
779 }
780 _in[_cnt++] = n; // Stuff over old prec edge
781 if (n != nullptr) n->add_out((Node *)this);
782 Compile::current()->record_modified_node(this);
783 }
784
785 //---------------------------add_req_batch-------------------------------------
786 // Add a new required input at the end
787 void Node::add_req_batch( Node *n, uint m ) {
788 assert( is_not_dead(n), "can not use dead node");
789 // check various edge cases
790 if ((int)m <= 1) {
791 assert((int)m >= 0, "oob");
792 if (m != 0) add_req(n);
793 return;
794 }
795
796 // Look to see if I can move precedence down one without reallocating
797 if( (_cnt+m) > _max || _in[_max-m] )
798 grow( _max+m );
799
800 // Find a precedence edge to move
801 if( _in[_cnt] != nullptr ) { // Next precedence edge is busy?
802 uint i;
803 for( i=_cnt; i<_max; i++ )
804 if( _in[i] == nullptr ) // Find the null at end of prec edge list
805 break; // There must be one, since we grew the array
806 // Slide all the precs over by m positions (assume #prec << m).
807 Copy::conjoint_words_to_higher((HeapWord*)&_in[_cnt], (HeapWord*)&_in[_cnt+m], ((i-_cnt)*sizeof(Node*)));
808 }
809
810 // Stuff over the old prec edges
811 for(uint i=0; i<m; i++ ) {
812 _in[_cnt++] = n;
813 }
814
815 // Insert multiple out edges on the node.
816 if (n != nullptr && !n->is_top()) {
817 for(uint i=0; i<m; i++ ) {
818 n->add_out((Node *)this);
819 }
820 }
821 Compile::current()->record_modified_node(this);
822 }
823
824 //------------------------------del_req----------------------------------------
825 // Delete the required edge and compact the edge array
826 void Node::del_req( uint idx ) {
827 assert( idx < _cnt, "oob");
828 assert( !VerifyHashTableKeys || _hash_lock == 0,
829 "remove node from hash table before modifying it");
830 // First remove corresponding def-use edge
831 Node *n = in(idx);
832 if (n != nullptr) n->del_out((Node *)this);
833 _in[idx] = in(--_cnt); // Compact the array
834 // Avoid spec violation: Gap in prec edges.
835 close_prec_gap_at(_cnt);
836 Compile::current()->record_modified_node(this);
837 }
838
839 //------------------------------del_req_ordered--------------------------------
840 // Delete the required edge and compact the edge array with preserved order
841 void Node::del_req_ordered( uint idx ) {
842 assert( idx < _cnt, "oob");
843 assert( !VerifyHashTableKeys || _hash_lock == 0,
844 "remove node from hash table before modifying it");
845 // First remove corresponding def-use edge
846 Node *n = in(idx);
847 if (n != nullptr) n->del_out((Node *)this);
848 if (idx < --_cnt) { // Not last edge ?
849 Copy::conjoint_words_to_lower((HeapWord*)&_in[idx+1], (HeapWord*)&_in[idx], ((_cnt-idx)*sizeof(Node*)));
850 }
851 // Avoid spec violation: Gap in prec edges.
852 close_prec_gap_at(_cnt);
853 Compile::current()->record_modified_node(this);
854 }
855
856 //------------------------------ins_req----------------------------------------
857 // Insert a new required input at the end
858 void Node::ins_req( uint idx, Node *n ) {
859 assert( is_not_dead(n), "can not use dead node");
860 add_req(nullptr); // Make space
861 assert( idx < _max, "Must have allocated enough space");
862 // Slide over
863 if(_cnt-idx-1 > 0) {
864 Copy::conjoint_words_to_higher((HeapWord*)&_in[idx], (HeapWord*)&_in[idx+1], ((_cnt-idx-1)*sizeof(Node*)));
865 }
866 _in[idx] = n; // Stuff over old required edge
867 if (n != nullptr) n->add_out((Node *)this); // Add reciprocal def-use edge
868 Compile::current()->record_modified_node(this);
869 }
870
871 //-----------------------------find_edge---------------------------------------
872 int Node::find_edge(Node* n) {
873 for (uint i = 0; i < len(); i++) {
874 if (_in[i] == n) return i;
875 }
876 return -1;
877 }
878
879 //----------------------------replace_edge-------------------------------------
880 int Node::replace_edge(Node* old, Node* neww, PhaseGVN* gvn) {
881 if (old == neww) return 0; // nothing to do
882 uint nrep = 0;
883 for (uint i = 0; i < len(); i++) {
884 if (in(i) == old) {
885 if (i < req()) {
886 if (gvn != nullptr) {
887 set_req_X(i, neww, gvn);
888 } else {
889 set_req(i, neww);
890 }
891 } else {
892 assert(gvn == nullptr || gvn->is_IterGVN() == nullptr, "no support for igvn here");
893 assert(find_prec_edge(neww) == -1, "spec violation: duplicated prec edge (node %d -> %d)", _idx, neww->_idx);
894 set_prec(i, neww);
895 }
896 nrep++;
897 }
898 }
899 return nrep;
900 }
901
902 /**
903 * Replace input edges in the range pointing to 'old' node.
904 */
905 int Node::replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn) {
906 if (old == neww) return 0; // nothing to do
907 uint nrep = 0;
908 for (int i = start; i < end; i++) {
909 if (in(i) == old) {
910 set_req_X(i, neww, gvn);
911 nrep++;
912 }
913 }
914 return nrep;
915 }
916
917 //-------------------------disconnect_inputs-----------------------------------
918 // null out all inputs to eliminate incoming Def-Use edges.
919 void Node::disconnect_inputs(Compile* C) {
920 // the layout of Node::_in
921 // r: a required input, null is allowed
922 // p: a precedence, null values are all at the end
923 // -----------------------------------
924 // |r|...|r|p|...|p|null|...|null|
925 // | |
926 // req() len()
927 // -----------------------------------
928 for (uint i = 0; i < req(); ++i) {
929 if (in(i) != nullptr) {
930 set_req(i, nullptr);
931 }
932 }
933
934 // Remove precedence edges if any exist
935 // Note: Safepoints may have precedence edges, even during parsing
936 for (uint i = len(); i > req(); ) {
937 rm_prec(--i); // no-op if _in[i] is null
938 }
939
940 #ifdef ASSERT
941 // sanity check
942 for (uint i = 0; i < len(); ++i) {
943 assert(_in[i] == nullptr, "disconnect_inputs() failed!");
944 }
945 #endif
946
947 // Node::destruct requires all out edges be deleted first
948 // DEBUG_ONLY(destruct();) // no reuse benefit expected
949 C->record_dead_node(_idx);
950 }
951
952 //-----------------------------uncast---------------------------------------
953 // %%% Temporary, until we sort out CheckCastPP vs. CastPP.
954 // Strip away casting. (It is depth-limited.)
955 // Optionally, keep casts with dependencies.
956 Node* Node::uncast(bool keep_deps) const {
957 // Should be inline:
958 //return is_ConstraintCast() ? uncast_helper(this) : (Node*) this;
959 if (is_ConstraintCast()) {
960 return uncast_helper(this, keep_deps);
961 } else {
962 return (Node*) this;
963 }
964 }
965
966 // Find out of current node that matches opcode.
967 Node* Node::find_out_with(int opcode) {
968 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
969 Node* use = fast_out(i);
970 if (use->Opcode() == opcode) {
971 return use;
972 }
973 }
974 return nullptr;
975 }
976
977 // Return true if the current node has an out that matches opcode.
978 bool Node::has_out_with(int opcode) {
979 return (find_out_with(opcode) != nullptr);
980 }
981
982 // Return true if the current node has an out that matches any of the opcodes.
983 bool Node::has_out_with(int opcode1, int opcode2, int opcode3, int opcode4) {
984 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
985 int opcode = fast_out(i)->Opcode();
986 if (opcode == opcode1 || opcode == opcode2 || opcode == opcode3 || opcode == opcode4) {
987 return true;
988 }
989 }
990 return false;
991 }
992
993
994 //---------------------------uncast_helper-------------------------------------
995 Node* Node::uncast_helper(const Node* p, bool keep_deps) {
996 #ifdef ASSERT
997 uint depth_count = 0;
998 const Node* orig_p = p;
999 #endif
1000
1001 while (true) {
1002 #ifdef ASSERT
1003 if (depth_count >= K) {
1004 orig_p->dump(4);
1005 if (p != orig_p)
1006 p->dump(1);
1007 }
1008 assert(depth_count++ < K, "infinite loop in Node::uncast_helper");
1009 #endif
1010 if (p == nullptr || p->req() != 2) {
1011 break;
1012 } else if (p->is_ConstraintCast()) {
1013 if (keep_deps && p->as_ConstraintCast()->carry_dependency()) {
1014 break; // stop at casts with dependencies
1015 }
1016 p = p->in(1);
1017 } else {
1018 break;
1019 }
1020 }
1021 return (Node*) p;
1022 }
1023
1024 //------------------------------add_prec---------------------------------------
1025 // Add a new precedence input. Precedence inputs are unordered, with
1026 // duplicates removed and nulls packed down at the end.
1027 void Node::add_prec( Node *n ) {
1028 assert( is_not_dead(n), "can not use dead node");
1029
1030 // Check for null at end
1031 if( _cnt >= _max || in(_max-1) )
1032 grow( _max+1 );
1033
1034 // Find a precedence edge to move
1035 uint i = _cnt;
1036 while( in(i) != nullptr ) {
1037 if (in(i) == n) return; // Avoid spec violation: duplicated prec edge.
1038 i++;
1039 }
1040 _in[i] = n; // Stuff prec edge over null
1041 if ( n != nullptr) n->add_out((Node *)this); // Add mirror edge
1042
1043 #ifdef ASSERT
1044 while ((++i)<_max) { assert(_in[i] == nullptr, "spec violation: Gap in prec edges (node %d)", _idx); }
1045 #endif
1046 Compile::current()->record_modified_node(this);
1047 }
1048
1049 //------------------------------rm_prec----------------------------------------
1050 // Remove a precedence input. Precedence inputs are unordered, with
1051 // duplicates removed and nulls packed down at the end.
1052 void Node::rm_prec( uint j ) {
1053 assert(j < _max, "oob: i=%d, _max=%d", j, _max);
1054 assert(j >= _cnt, "not a precedence edge");
1055 if (_in[j] == nullptr) return; // Avoid spec violation: Gap in prec edges.
1056 _in[j]->del_out((Node *)this);
1057 close_prec_gap_at(j);
1058 Compile::current()->record_modified_node(this);
1059 }
1060
1061 //------------------------------size_of----------------------------------------
1062 uint Node::size_of() const { return sizeof(*this); }
1063
1064 //------------------------------ideal_reg--------------------------------------
1065 uint Node::ideal_reg() const { return 0; }
1066
1067 //------------------------------jvms-------------------------------------------
1068 JVMState* Node::jvms() const { return nullptr; }
1069
1070 #ifdef ASSERT
1071 //------------------------------jvms-------------------------------------------
1072 bool Node::verify_jvms(const JVMState* using_jvms) const {
1073 for (JVMState* jvms = this->jvms(); jvms != nullptr; jvms = jvms->caller()) {
1074 if (jvms == using_jvms) return true;
1075 }
1076 return false;
1077 }
1078
1079 //------------------------------init_NodeProperty------------------------------
1080 void Node::init_NodeProperty() {
1081 assert(_max_classes <= max_juint, "too many NodeProperty classes");
1082 assert(max_flags() <= max_juint, "too many NodeProperty flags");
1083 }
1084
1085 //-----------------------------max_flags---------------------------------------
1086 juint Node::max_flags() {
1087 return (PD::_last_flag << 1) - 1; // allow flags combination
1088 }
1089 #endif
1090
1091 //------------------------------format-----------------------------------------
1092 // Print as assembly
1093 void Node::format( PhaseRegAlloc *, outputStream *st ) const {}
1094 //------------------------------emit-------------------------------------------
1095 // Emit bytes using C2_MacroAssembler
1096 void Node::emit(C2_MacroAssembler *masm, PhaseRegAlloc *ra_) const {}
1097 //------------------------------size-------------------------------------------
1098 // Size of instruction in bytes
1099 uint Node::size(PhaseRegAlloc *ra_) const { return 0; }
1100
1101 //------------------------------CFG Construction-------------------------------
1102 // Nodes that end basic blocks, e.g. IfTrue/IfFalse, JumpProjNode, Root,
1103 // Goto and Return.
1104 const Node *Node::is_block_proj() const { return nullptr; }
1105
1106 // Minimum guaranteed type
1107 const Type *Node::bottom_type() const { return Type::BOTTOM; }
1108
1109
1110 //------------------------------raise_bottom_type------------------------------
1111 // Get the worst-case Type output for this Node.
1112 void Node::raise_bottom_type(const Type* new_type) {
1113 if (is_Type()) {
1114 TypeNode *n = this->as_Type();
1115 if (VerifyAliases) {
1116 assert(new_type->higher_equal_speculative(n->type()), "new type must refine old type");
1117 }
1118 n->set_type(new_type);
1119 } else if (is_Load()) {
1120 LoadNode *n = this->as_Load();
1121 if (VerifyAliases) {
1122 assert(new_type->higher_equal_speculative(n->type()), "new type must refine old type");
1123 }
1124 n->set_type(new_type);
1125 }
1126 }
1127
1128 //------------------------------Identity---------------------------------------
1129 // Return a node that the given node is equivalent to.
1130 Node* Node::Identity(PhaseGVN* phase) {
1131 return this; // Default to no identities
1132 }
1133
1134 //------------------------------Value------------------------------------------
1135 // Compute a new Type for a node using the Type of the inputs.
1136 const Type* Node::Value(PhaseGVN* phase) const {
1137 return bottom_type(); // Default to worst-case Type
1138 }
1139
1140 //------------------------------Ideal------------------------------------------
1141 //
1142 // 'Idealize' the graph rooted at this Node.
1143 //
1144 // In order to be efficient and flexible there are some subtle invariants
1145 // these Ideal calls need to hold. Running with '-XX:VerifyIterativeGVN=1' checks
1146 // these invariants, although its too slow to have on by default. If you are
1147 // hacking an Ideal call, be sure to test with '-XX:VerifyIterativeGVN=1'
1148 //
1149 // The Ideal call almost arbitrarily reshape the graph rooted at the 'this'
1150 // pointer. If ANY change is made, it must return the root of the reshaped
1151 // graph - even if the root is the same Node. Example: swapping the inputs
1152 // to an AddINode gives the same answer and same root, but you still have to
1153 // return the 'this' pointer instead of null.
1154 //
1155 // You cannot return an OLD Node, except for the 'this' pointer. Use the
1156 // Identity call to return an old Node; basically if Identity can find
1157 // another Node have the Ideal call make no change and return null.
1158 // Example: AddINode::Ideal must check for add of zero; in this case it
1159 // returns null instead of doing any graph reshaping.
1160 //
1161 // You cannot modify any old Nodes except for the 'this' pointer. Due to
1162 // sharing there may be other users of the old Nodes relying on their current
1163 // semantics. Modifying them will break the other users.
1164 // Example: when reshape "(X+3)+4" into "X+7" you must leave the Node for
1165 // "X+3" unchanged in case it is shared.
1166 //
1167 // If you modify the 'this' pointer's inputs, you should use
1168 // 'set_req'. If you are making a new Node (either as the new root or
1169 // some new internal piece) you may use 'init_req' to set the initial
1170 // value. You can make a new Node with either 'new' or 'clone'. In
1171 // either case, def-use info is correctly maintained.
1172 //
1173 // Example: reshape "(X+3)+4" into "X+7":
1174 // set_req(1, in(1)->in(1));
1175 // set_req(2, phase->intcon(7));
1176 // return this;
1177 // Example: reshape "X*4" into "X<<2"
1178 // return new LShiftINode(in(1), phase->intcon(2));
1179 //
1180 // You must call 'phase->transform(X)' on any new Nodes X you make, except
1181 // for the returned root node. Example: reshape "X*31" with "(X<<5)-X".
1182 // Node *shift=phase->transform(new LShiftINode(in(1),phase->intcon(5)));
1183 // return new AddINode(shift, in(1));
1184 //
1185 // When making a Node for a constant use 'phase->makecon' or 'phase->intcon'.
1186 // These forms are faster than 'phase->transform(new ConNode())' and Do
1187 // The Right Thing with def-use info.
1188 //
1189 // You cannot bury the 'this' Node inside of a graph reshape. If the reshaped
1190 // graph uses the 'this' Node it must be the root. If you want a Node with
1191 // the same Opcode as the 'this' pointer use 'clone'.
1192 //
1193 Node *Node::Ideal(PhaseGVN *phase, bool can_reshape) {
1194 return nullptr; // Default to being Ideal already
1195 }
1196
1197 // Some nodes have specific Ideal subgraph transformations only if they are
1198 // unique users of specific nodes. Such nodes should be put on IGVN worklist
1199 // for the transformations to happen.
1200 bool Node::has_special_unique_user() const {
1201 assert(outcnt() == 1, "match only for unique out");
1202 Node* n = unique_out();
1203 int op = Opcode();
1204 if (this->is_Store()) {
1205 // Condition for back-to-back stores folding.
1206 return n->Opcode() == op && n->in(MemNode::Memory) == this;
1207 } else if (this->is_Load() || this->is_DecodeN() || this->is_Phi()) {
1208 // Condition for removing an unused LoadNode or DecodeNNode from the MemBarAcquire precedence input
1209 return n->Opcode() == Op_MemBarAcquire;
1210 } else if (op == Op_AddL) {
1211 // Condition for convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
1212 return n->Opcode() == Op_ConvL2I && n->in(1) == this;
1213 } else if (op == Op_SubI || op == Op_SubL) {
1214 // Condition for subI(x,subI(y,z)) ==> subI(addI(x,z),y)
1215 return n->Opcode() == op && n->in(2) == this;
1216 } else if (is_If() && (n->is_IfFalse() || n->is_IfTrue())) {
1217 // See IfProjNode::Identity()
1218 return true;
1219 } else if ((is_IfFalse() || is_IfTrue()) && n->is_If()) {
1220 // See IfNode::fold_compares
1221 return true;
1222 } else if (n->Opcode() == Op_XorV || n->Opcode() == Op_XorVMask) {
1223 // Condition for XorVMask(VectorMaskCmp(x,y,cond), MaskAll(true)) ==> VectorMaskCmp(x,y,ncond)
1224 return true;
1225 } else {
1226 return false;
1227 }
1228 };
1229
1230 //--------------------------find_exact_control---------------------------------
1231 // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1232 Node* Node::find_exact_control(Node* ctrl) {
1233 if (ctrl == nullptr && this->is_Region())
1234 ctrl = this->as_Region()->is_copy();
1235
1236 if (ctrl != nullptr && ctrl->is_CatchProj()) {
1237 if (ctrl->as_CatchProj()->_con == CatchProjNode::fall_through_index)
1238 ctrl = ctrl->in(0);
1239 if (ctrl != nullptr && !ctrl->is_top())
1240 ctrl = ctrl->in(0);
1241 }
1242
1243 if (ctrl != nullptr && ctrl->is_Proj())
1244 ctrl = ctrl->in(0);
1245
1246 return ctrl;
1247 }
1248
1249 //--------------------------dominates------------------------------------------
1250 // Helper function for MemNode::all_controls_dominate().
1251 // Check if 'this' control node dominates or equal to 'sub' control node.
1252 // We already know that if any path back to Root or Start reaches 'this',
1253 // then all paths so, so this is a simple search for one example,
1254 // not an exhaustive search for a counterexample.
1255 Node::DomResult Node::dominates(Node* sub, Node_List &nlist) {
1256 assert(this->is_CFG(), "expecting control");
1257 assert(sub != nullptr && sub->is_CFG(), "expecting control");
1258
1259 // detect dead cycle without regions
1260 int iterations_without_region_limit = DominatorSearchLimit;
1261
1262 Node* orig_sub = sub;
1263 Node* dom = this;
1264 bool met_dom = false;
1265 nlist.clear();
1266
1267 // Walk 'sub' backward up the chain to 'dom', watching for regions.
1268 // After seeing 'dom', continue up to Root or Start.
1269 // If we hit a region (backward split point), it may be a loop head.
1270 // Keep going through one of the region's inputs. If we reach the
1271 // same region again, go through a different input. Eventually we
1272 // will either exit through the loop head, or give up.
1273 // (If we get confused, break out and return a conservative 'false'.)
1274 while (sub != nullptr) {
1275 if (sub->is_top()) {
1276 // Conservative answer for dead code.
1277 return DomResult::EncounteredDeadCode;
1278 }
1279 if (sub == dom) {
1280 if (nlist.size() == 0) {
1281 // No Region nodes except loops were visited before and the EntryControl
1282 // path was taken for loops: it did not walk in a cycle.
1283 return DomResult::Dominate;
1284 } else if (met_dom) {
1285 break; // already met before: walk in a cycle
1286 } else {
1287 // Region nodes were visited. Continue walk up to Start or Root
1288 // to make sure that it did not walk in a cycle.
1289 met_dom = true; // first time meet
1290 iterations_without_region_limit = DominatorSearchLimit; // Reset
1291 }
1292 }
1293 if (sub->is_Start() || sub->is_Root()) {
1294 // Success if we met 'dom' along a path to Start or Root.
1295 // We assume there are no alternative paths that avoid 'dom'.
1296 // (This assumption is up to the caller to ensure!)
1297 return met_dom ? DomResult::Dominate : DomResult::NotDominate;
1298 }
1299 Node* up = sub->in(0);
1300 // Normalize simple pass-through regions and projections:
1301 up = sub->find_exact_control(up);
1302 // If sub == up, we found a self-loop. Try to push past it.
1303 if (sub == up && sub->is_Loop()) {
1304 // Take loop entry path on the way up to 'dom'.
1305 up = sub->in(1); // in(LoopNode::EntryControl);
1306 } else if (sub == up && sub->is_Region() && sub->req() == 2) {
1307 // Take in(1) path on the way up to 'dom' for regions with only one input
1308 up = sub->in(1);
1309 } else if (sub == up && sub->is_Region()) {
1310 // Try both paths for Regions with 2 input paths (it may be a loop head).
1311 // It could give conservative 'false' answer without information
1312 // which region's input is the entry path.
1313 iterations_without_region_limit = DominatorSearchLimit; // Reset
1314
1315 bool region_was_visited_before = false;
1316 // Was this Region node visited before?
1317 // If so, we have reached it because we accidentally took a
1318 // loop-back edge from 'sub' back into the body of the loop,
1319 // and worked our way up again to the loop header 'sub'.
1320 // So, take the first unexplored path on the way up to 'dom'.
1321 for (int j = nlist.size() - 1; j >= 0; j--) {
1322 intptr_t ni = (intptr_t)nlist.at(j);
1323 Node* visited = (Node*)(ni & ~1);
1324 bool visited_twice_already = ((ni & 1) != 0);
1325 if (visited == sub) {
1326 if (visited_twice_already) {
1327 // Visited 2 paths, but still stuck in loop body. Give up.
1328 return DomResult::NotDominate;
1329 }
1330 // The Region node was visited before only once.
1331 // (We will repush with the low bit set, below.)
1332 nlist.remove(j);
1333 // We will find a new edge and re-insert.
1334 region_was_visited_before = true;
1335 break;
1336 }
1337 }
1338
1339 // Find an incoming edge which has not been seen yet; walk through it.
1340 assert(up == sub, "");
1341 uint skip = region_was_visited_before ? 1 : 0;
1342 for (uint i = 1; i < sub->req(); i++) {
1343 Node* in = sub->in(i);
1344 if (in != nullptr && !in->is_top() && in != sub) {
1345 if (skip == 0) {
1346 up = in;
1347 break;
1348 }
1349 --skip; // skip this nontrivial input
1350 }
1351 }
1352
1353 // Set 0 bit to indicate that both paths were taken.
1354 nlist.push((Node*)((intptr_t)sub + (region_was_visited_before ? 1 : 0)));
1355 }
1356
1357 if (up == sub) {
1358 break; // some kind of tight cycle
1359 }
1360 if (up == orig_sub && met_dom) {
1361 // returned back after visiting 'dom'
1362 break; // some kind of cycle
1363 }
1364 if (--iterations_without_region_limit < 0) {
1365 break; // dead cycle
1366 }
1367 sub = up;
1368 }
1369
1370 // Did not meet Root or Start node in pred. chain.
1371 return DomResult::NotDominate;
1372 }
1373
1374 //------------------------------remove_dead_region-----------------------------
1375 // This control node is dead. Follow the subgraph below it making everything
1376 // using it dead as well. This will happen normally via the usual IterGVN
1377 // worklist but this call is more efficient. Do not update use-def info
1378 // inside the dead region, just at the borders.
1379 static void kill_dead_code( Node *dead, PhaseIterGVN *igvn ) {
1380 // Con's are a popular node to re-hit in the hash table again.
1381 if( dead->is_Con() ) return;
1382
1383 ResourceMark rm;
1384 Node_List nstack;
1385 VectorSet dead_set; // notify uses only once
1386
1387 Node *top = igvn->C->top();
1388 nstack.push(dead);
1389 bool has_irreducible_loop = igvn->C->has_irreducible_loop();
1390
1391 while (nstack.size() > 0) {
1392 dead = nstack.pop();
1393 if (!dead_set.test_set(dead->_idx)) {
1394 // If dead has any live uses, those are now still attached. Notify them before we lose them.
1395 igvn->add_users_to_worklist(dead);
1396 }
1397 if (dead->Opcode() == Op_SafePoint) {
1398 dead->as_SafePoint()->disconnect_from_root(igvn);
1399 }
1400 if (dead->outcnt() > 0) {
1401 // Keep dead node on stack until all uses are processed.
1402 nstack.push(dead);
1403 // For all Users of the Dead... ;-)
1404 for (DUIterator_Last kmin, k = dead->last_outs(kmin); k >= kmin; ) {
1405 Node* use = dead->last_out(k);
1406 igvn->hash_delete(use); // Yank from hash table prior to mod
1407 if (use->in(0) == dead) { // Found another dead node
1408 assert (!use->is_Con(), "Control for Con node should be Root node.");
1409 use->set_req(0, top); // Cut dead edge to prevent processing
1410 nstack.push(use); // the dead node again.
1411 } else if (!has_irreducible_loop && // Backedge could be alive in irreducible loop
1412 use->is_Loop() && !use->is_Root() && // Don't kill Root (RootNode extends LoopNode)
1413 use->in(LoopNode::EntryControl) == dead) { // Dead loop if its entry is dead
1414 use->set_req(LoopNode::EntryControl, top); // Cut dead edge to prevent processing
1415 use->set_req(0, top); // Cut self edge
1416 nstack.push(use);
1417 } else { // Else found a not-dead user
1418 // Dead if all inputs are top or null
1419 bool dead_use = !use->is_Root(); // Keep empty graph alive
1420 for (uint j = 1; j < use->req(); j++) {
1421 Node* in = use->in(j);
1422 if (in == dead) { // Turn all dead inputs into TOP
1423 use->set_req(j, top);
1424 } else if (in != nullptr && !in->is_top()) {
1425 dead_use = false;
1426 }
1427 }
1428 if (dead_use) {
1429 if (use->is_Region()) {
1430 use->set_req(0, top); // Cut self edge
1431 }
1432 nstack.push(use);
1433 } else {
1434 igvn->_worklist.push(use);
1435 }
1436 }
1437 // Refresh the iterator, since any number of kills might have happened.
1438 k = dead->last_outs(kmin);
1439 }
1440 } else { // (dead->outcnt() == 0)
1441 // Done with outputs.
1442 igvn->hash_delete(dead);
1443 igvn->_worklist.remove(dead);
1444 igvn->set_type(dead, Type::TOP);
1445 // Kill all inputs to the dead guy
1446 for (uint i=0; i < dead->req(); i++) {
1447 Node *n = dead->in(i); // Get input to dead guy
1448 if (n != nullptr && !n->is_top()) { // Input is valid?
1449 dead->set_req(i, top); // Smash input away
1450 if (n->outcnt() == 0) { // Input also goes dead?
1451 if (!n->is_Con())
1452 nstack.push(n); // Clear it out as well
1453 } else if (n->outcnt() == 1 &&
1454 n->has_special_unique_user()) {
1455 igvn->add_users_to_worklist( n );
1456 } else if (n->outcnt() <= 2 && n->is_Store()) {
1457 // Push store's uses on worklist to enable folding optimization for
1458 // store/store and store/load to the same address.
1459 // The restriction (outcnt() <= 2) is the same as in set_req_X()
1460 // and remove_globally_dead_node().
1461 igvn->add_users_to_worklist( n );
1462 } else if (dead->is_data_proj_of_pure_function(n)) {
1463 igvn->_worklist.push(n);
1464 }
1465 }
1466 }
1467 igvn->C->remove_useless_node(dead);
1468 } // (dead->outcnt() == 0)
1469 } // while (nstack.size() > 0) for outputs
1470 return;
1471 }
1472
1473 //------------------------------remove_dead_region-----------------------------
1474 bool Node::remove_dead_region(PhaseGVN *phase, bool can_reshape) {
1475 Node *n = in(0);
1476 if( !n ) return false;
1477 // Lost control into this guy? I.e., it became unreachable?
1478 // Aggressively kill all unreachable code.
1479 if (can_reshape && n->is_top()) {
1480 kill_dead_code(this, phase->is_IterGVN());
1481 return false; // Node is dead.
1482 }
1483
1484 if( n->is_Region() && n->as_Region()->is_copy() ) {
1485 Node *m = n->nonnull_req();
1486 set_req(0, m);
1487 return true;
1488 }
1489 return false;
1490 }
1491
1492 //------------------------------hash-------------------------------------------
1493 // Hash function over Nodes.
1494 uint Node::hash() const {
1495 uint sum = 0;
1496 for( uint i=0; i<_cnt; i++ ) // Add in all inputs
1497 sum = (sum<<1)-(uintptr_t)in(i); // Ignore embedded nulls
1498 return (sum>>2) + _cnt + Opcode();
1499 }
1500
1501 //------------------------------cmp--------------------------------------------
1502 // Compare special parts of simple Nodes
1503 bool Node::cmp( const Node &n ) const {
1504 return true; // Must be same
1505 }
1506
1507 //------------------------------rematerialize-----------------------------------
1508 // Should we clone rather than spill this instruction?
1509 bool Node::rematerialize() const {
1510 if ( is_Mach() )
1511 return this->as_Mach()->rematerialize();
1512 else
1513 return (_flags & Flag_rematerialize) != 0;
1514 }
1515
1516 //------------------------------needs_anti_dependence_check---------------------
1517 // Nodes which use memory without consuming it, hence need antidependences.
1518 bool Node::needs_anti_dependence_check() const {
1519 if (req() < 2 || (_flags & Flag_needs_anti_dependence_check) == 0) {
1520 return false;
1521 }
1522 return in(1)->bottom_type()->has_memory();
1523 }
1524
1525 // Get an integer constant from a ConNode (or CastIINode).
1526 // Return a default value if there is no apparent constant here.
1527 const TypeInt* Node::find_int_type() const {
1528 if (this->is_Type()) {
1529 return this->as_Type()->type()->isa_int();
1530 } else if (this->is_Con()) {
1531 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1532 return this->bottom_type()->isa_int();
1533 }
1534 return nullptr;
1535 }
1536
1537 const TypeInteger* Node::find_integer_type(BasicType bt) const {
1538 if (this->is_Type()) {
1539 return this->as_Type()->type()->isa_integer(bt);
1540 } else if (this->is_Con()) {
1541 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1542 return this->bottom_type()->isa_integer(bt);
1543 }
1544 return nullptr;
1545 }
1546
1547 // Get a pointer constant from a ConstNode.
1548 // Returns the constant if it is a pointer ConstNode
1549 intptr_t Node::get_ptr() const {
1550 assert( Opcode() == Op_ConP, "" );
1551 return ((ConPNode*)this)->type()->is_ptr()->get_con();
1552 }
1553
1554 // Get a narrow oop constant from a ConNNode.
1555 intptr_t Node::get_narrowcon() const {
1556 assert( Opcode() == Op_ConN, "" );
1557 return ((ConNNode*)this)->type()->is_narrowoop()->get_con();
1558 }
1559
1560 // Get a long constant from a ConNode.
1561 // Return a default value if there is no apparent constant here.
1562 const TypeLong* Node::find_long_type() const {
1563 if (this->is_Type()) {
1564 return this->as_Type()->type()->isa_long();
1565 } else if (this->is_Con()) {
1566 assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1567 return this->bottom_type()->isa_long();
1568 }
1569 return nullptr;
1570 }
1571
1572
1573 /**
1574 * Return a ptr type for nodes which should have it.
1575 */
1576 const TypePtr* Node::get_ptr_type() const {
1577 const TypePtr* tp = this->bottom_type()->make_ptr();
1578 #ifdef ASSERT
1579 if (tp == nullptr) {
1580 this->dump(1);
1581 assert((tp != nullptr), "unexpected node type");
1582 }
1583 #endif
1584 return tp;
1585 }
1586
1587 // Get a double constant from a ConstNode.
1588 // Returns the constant if it is a double ConstNode
1589 jdouble Node::getd() const {
1590 assert( Opcode() == Op_ConD, "" );
1591 return ((ConDNode*)this)->type()->is_double_constant()->getd();
1592 }
1593
1594 // Get a float constant from a ConstNode.
1595 // Returns the constant if it is a float ConstNode
1596 jfloat Node::getf() const {
1597 assert( Opcode() == Op_ConF, "" );
1598 return ((ConFNode*)this)->type()->is_float_constant()->getf();
1599 }
1600
1601 // Get a half float constant from a ConstNode.
1602 // Returns the constant if it is a float ConstNode
1603 jshort Node::geth() const {
1604 assert( Opcode() == Op_ConH, "" );
1605 return ((ConHNode*)this)->type()->is_half_float_constant()->geth();
1606 }
1607
1608 #ifndef PRODUCT
1609
1610 // Call this from debugger:
1611 Node* old_root() {
1612 Matcher* matcher = Compile::current()->matcher();
1613 if (matcher != nullptr) {
1614 Node* new_root = Compile::current()->root();
1615 Node* old_root = matcher->find_old_node(new_root);
1616 if (old_root != nullptr) {
1617 return old_root;
1618 }
1619 }
1620 tty->print("old_root: not found.\n");
1621 return nullptr;
1622 }
1623
1624 // BFS traverse all reachable nodes from start, call callback on them
1625 template <typename Callback>
1626 void visit_nodes(Node* start, Callback callback, bool traverse_output, bool only_ctrl) {
1627 Unique_Mixed_Node_List worklist;
1628 worklist.add(start);
1629 for (uint i = 0; i < worklist.size(); i++) {
1630 Node* n = worklist[i];
1631 callback(n);
1632 for (uint i = 0; i < n->len(); i++) {
1633 if (!only_ctrl || n->is_Region() || (n->Opcode() == Op_Root) || (i == TypeFunc::Control)) {
1634 // If only_ctrl is set: Add regions, the root node, or control inputs only
1635 worklist.add(n->in(i));
1636 }
1637 }
1638 if (traverse_output && !only_ctrl) {
1639 for (uint i = 0; i < n->outcnt(); i++) {
1640 worklist.add(n->raw_out(i));
1641 }
1642 }
1643 }
1644 }
1645
1646 // BFS traverse from start, return node with idx
1647 static Node* find_node_by_idx(Node* start, uint idx, bool traverse_output, bool only_ctrl) {
1648 ResourceMark rm;
1649 Node* result = nullptr;
1650 auto callback = [&] (Node* n) {
1651 if (n->_idx == idx) {
1652 if (result != nullptr) {
1653 tty->print("find_node_by_idx: " INTPTR_FORMAT " and " INTPTR_FORMAT " both have idx==%d\n",
1654 (uintptr_t)result, (uintptr_t)n, idx);
1655 }
1656 result = n;
1657 }
1658 };
1659 visit_nodes(start, callback, traverse_output, only_ctrl);
1660 return result;
1661 }
1662
1663 static int node_idx_cmp(const Node** n1, const Node** n2) {
1664 return (*n1)->_idx - (*n2)->_idx;
1665 }
1666
1667 static void find_nodes_by_name(Node* start, const char* name) {
1668 ResourceMark rm;
1669 GrowableArray<const Node*> ns;
1670 auto callback = [&] (const Node* n) {
1671 if (StringUtils::is_star_match(name, n->Name())) {
1672 ns.push(n);
1673 }
1674 };
1675 visit_nodes(start, callback, true, false);
1676 ns.sort(node_idx_cmp);
1677 for (int i = 0; i < ns.length(); i++) {
1678 ns.at(i)->dump();
1679 }
1680 }
1681
1682 static void find_nodes_by_dump(Node* start, const char* pattern) {
1683 ResourceMark rm;
1684 GrowableArray<const Node*> ns;
1685 auto callback = [&] (const Node* n) {
1686 stringStream stream;
1687 n->dump("", false, &stream);
1688 if (StringUtils::is_star_match(pattern, stream.base())) {
1689 ns.push(n);
1690 }
1691 };
1692 visit_nodes(start, callback, true, false);
1693 ns.sort(node_idx_cmp);
1694 for (int i = 0; i < ns.length(); i++) {
1695 ns.at(i)->dump();
1696 }
1697 }
1698
1699 // call from debugger: find node with name pattern in new/current graph
1700 // name can contain "*" in match pattern to match any characters
1701 // the matching is case insensitive
1702 void find_nodes_by_name(const char* name) {
1703 Node* root = Compile::current()->root();
1704 find_nodes_by_name(root, name);
1705 }
1706
1707 // call from debugger: find node with name pattern in old graph
1708 // name can contain "*" in match pattern to match any characters
1709 // the matching is case insensitive
1710 void find_old_nodes_by_name(const char* name) {
1711 Node* root = old_root();
1712 find_nodes_by_name(root, name);
1713 }
1714
1715 // call from debugger: find node with dump pattern in new/current graph
1716 // can contain "*" in match pattern to match any characters
1717 // the matching is case insensitive
1718 void find_nodes_by_dump(const char* pattern) {
1719 Node* root = Compile::current()->root();
1720 find_nodes_by_dump(root, pattern);
1721 }
1722
1723 // call from debugger: find node with name pattern in old graph
1724 // can contain "*" in match pattern to match any characters
1725 // the matching is case insensitive
1726 void find_old_nodes_by_dump(const char* pattern) {
1727 Node* root = old_root();
1728 find_nodes_by_dump(root, pattern);
1729 }
1730
1731 // Call this from debugger, search in same graph as n:
1732 Node* find_node(Node* n, const int idx) {
1733 return n->find(idx);
1734 }
1735
1736 // Call this from debugger, search in new nodes:
1737 Node* find_node(const int idx) {
1738 return Compile::current()->root()->find(idx);
1739 }
1740
1741 // Call this from debugger, search in old nodes:
1742 Node* find_old_node(const int idx) {
1743 Node* root = old_root();
1744 return (root == nullptr) ? nullptr : root->find(idx);
1745 }
1746
1747 // Call this from debugger, search in same graph as n:
1748 Node* find_ctrl(Node* n, const int idx) {
1749 return n->find_ctrl(idx);
1750 }
1751
1752 // Call this from debugger, search in new nodes:
1753 Node* find_ctrl(const int idx) {
1754 return Compile::current()->root()->find_ctrl(idx);
1755 }
1756
1757 // Call this from debugger, search in old nodes:
1758 Node* find_old_ctrl(const int idx) {
1759 Node* root = old_root();
1760 return (root == nullptr) ? nullptr : root->find_ctrl(idx);
1761 }
1762
1763 //------------------------------find_ctrl--------------------------------------
1764 // Find an ancestor to this node in the control history with given _idx
1765 Node* Node::find_ctrl(int idx) {
1766 return find(idx, true);
1767 }
1768
1769 //------------------------------find-------------------------------------------
1770 // Tries to find the node with the index |idx| starting from this node. If idx is negative,
1771 // the search also includes forward (out) edges. Returns null if not found.
1772 // If only_ctrl is set, the search will only be done on control nodes. Returns null if
1773 // not found or if the node to be found is not a control node (search will not find it).
1774 Node* Node::find(const int idx, bool only_ctrl) {
1775 ResourceMark rm;
1776 return find_node_by_idx(this, abs(idx), (idx < 0), only_ctrl);
1777 }
1778
1779 class PrintBFS {
1780 public:
1781 PrintBFS(const Node* start, const int max_distance, const Node* target, const char* options, outputStream* st, const frame* fr)
1782 : _start(start), _max_distance(max_distance), _target(target), _options(options), _output(st), _frame(fr),
1783 _dcc(this), _info_uid(cmpkey, hashkey) {}
1784
1785 void run();
1786 private:
1787 // pipeline steps
1788 bool configure();
1789 void collect();
1790 void select();
1791 void select_all();
1792 void select_all_paths();
1793 void select_shortest_path();
1794 void sort();
1795 void print();
1796
1797 // inputs
1798 const Node* _start;
1799 const int _max_distance;
1800 const Node* _target;
1801 const char* _options;
1802 outputStream* _output;
1803 const frame* _frame;
1804
1805 // options
1806 bool _traverse_inputs = false;
1807 bool _traverse_outputs = false;
1808 struct Filter {
1809 bool _control = false;
1810 bool _memory = false;
1811 bool _data = false;
1812 bool _mixed = false;
1813 bool _other = false;
1814 bool is_empty() const {
1815 return !(_control || _memory || _data || _mixed || _other);
1816 }
1817 void set_all() {
1818 _control = true;
1819 _memory = true;
1820 _data = true;
1821 _mixed = true;
1822 _other = true;
1823 }
1824 // Check if the filter accepts the node. Go by the type categories, but also all CFG nodes
1825 // are considered to have control.
1826 bool accepts(const Node* n) {
1827 const Type* t = n->bottom_type();
1828 return ( _data && t->has_category(Type::Category::Data) ) ||
1829 ( _memory && t->has_category(Type::Category::Memory) ) ||
1830 ( _mixed && t->has_category(Type::Category::Mixed) ) ||
1831 ( _control && (t->has_category(Type::Category::Control) || n->is_CFG()) ) ||
1832 ( _other && t->has_category(Type::Category::Other) );
1833 }
1834 };
1835 Filter _filter_visit;
1836 Filter _filter_boundary;
1837 bool _sort_idx = false;
1838 bool _all_paths = false;
1839 bool _use_color = false;
1840 bool _print_blocks = false;
1841 bool _print_old = false;
1842 bool _dump_only = false;
1843 bool _print_igv = false;
1844
1845 void print_options_help(bool print_examples);
1846 bool parse_options();
1847
1848 public:
1849 class DumpConfigColored : public Node::DumpConfig {
1850 public:
1851 DumpConfigColored(PrintBFS* bfs) : _bfs(bfs) {};
1852 virtual void pre_dump(outputStream* st, const Node* n);
1853 virtual void post_dump(outputStream* st);
1854 private:
1855 PrintBFS* _bfs;
1856 };
1857 private:
1858 DumpConfigColored _dcc;
1859
1860 // node info
1861 static Node* old_node(const Node* n); // mach node -> prior IR node
1862 void print_node_idx(const Node* n);
1863 void print_block_id(const Block* b);
1864 void print_node_block(const Node* n); // _pre_order, head idx, _idom, _dom_depth
1865
1866 // traversal data structures
1867 GrowableArray<const Node*> _worklist; // BFS queue
1868 void maybe_traverse(const Node* src, const Node* dst);
1869
1870 // node info annotation
1871 class Info {
1872 public:
1873 Info() : Info(nullptr, 0) {};
1874 Info(const Node* node, int distance)
1875 : _node(node), _distance_from_start(distance) {};
1876 const Node* node() const { return _node; };
1877 int distance() const { return _distance_from_start; };
1878 int distance_from_target() const { return _distance_from_target; }
1879 void set_distance_from_target(int d) { _distance_from_target = d; }
1880 GrowableArray<const Node*> edge_bwd; // pointing toward _start
1881 bool is_marked() const { return _mark; } // marked to keep during select
1882 void set_mark() { _mark = true; }
1883 private:
1884 const Node* _node;
1885 int _distance_from_start; // distance from _start
1886 int _distance_from_target = 0; // distance from _target if _all_paths
1887 bool _mark = false;
1888 };
1889 Dict _info_uid; // Node -> uid
1890 GrowableArray<Info> _info; // uid -> info
1891
1892 Info* find_info(const Node* n) {
1893 size_t uid = (size_t)_info_uid[n];
1894 if (uid == 0) {
1895 return nullptr;
1896 }
1897 return &_info.at((int)uid);
1898 }
1899
1900 void make_info(const Node* node, const int distance) {
1901 assert(find_info(node) == nullptr, "node does not yet have info");
1902 size_t uid = _info.length() + 1;
1903 _info_uid.Insert((void*)node, (void*)uid);
1904 _info.at_put_grow((int)uid, Info(node, distance));
1905 assert(find_info(node)->node() == node, "stored correct node");
1906 };
1907
1908 // filled by sort, printed by print
1909 GrowableArray<const Node*> _print_list;
1910
1911 // print header + node table
1912 void print_header() const;
1913 void print_node(const Node* n);
1914 };
1915
1916 void PrintBFS::run() {
1917 if (!configure()) {
1918 return;
1919 }
1920 collect();
1921 select();
1922 sort();
1923 print();
1924 }
1925
1926 // set up configuration for BFS and print
1927 bool PrintBFS::configure() {
1928 if (_max_distance < 0) {
1929 _output->print_cr("dump_bfs: max_distance must be non-negative!");
1930 return false;
1931 }
1932 return parse_options();
1933 }
1934
1935 // BFS traverse according to configuration, fill worklist and info
1936 void PrintBFS::collect() {
1937 maybe_traverse(_start, _start);
1938 int pos = 0;
1939 while (pos < _worklist.length()) {
1940 const Node* n = _worklist.at(pos++); // next node to traverse
1941 Info* info = find_info(n);
1942 if (!_filter_visit.accepts(n) && n != _start) {
1943 continue; // we hit boundary, do not traverse further
1944 }
1945 if (n != _start && n->is_Root()) {
1946 continue; // traversing through root node would lead to unrelated nodes
1947 }
1948 if (_traverse_inputs && _max_distance > info->distance()) {
1949 for (uint i = 0; i < n->req(); i++) {
1950 maybe_traverse(n, n->in(i));
1951 }
1952 }
1953 if (_traverse_outputs && _max_distance > info->distance()) {
1954 for (uint i = 0; i < n->outcnt(); i++) {
1955 maybe_traverse(n, n->raw_out(i));
1956 }
1957 }
1958 }
1959 }
1960
1961 // go through work list, mark those that we want to print
1962 void PrintBFS::select() {
1963 if (_target == nullptr ) {
1964 select_all();
1965 } else {
1966 if (find_info(_target) == nullptr) {
1967 _output->print_cr("Could not find target in BFS.");
1968 return;
1969 }
1970 if (_all_paths) {
1971 select_all_paths();
1972 } else {
1973 select_shortest_path();
1974 }
1975 }
1976 }
1977
1978 // take all nodes from BFS
1979 void PrintBFS::select_all() {
1980 for (int i = 0; i < _worklist.length(); i++) {
1981 const Node* n = _worklist.at(i);
1982 Info* info = find_info(n);
1983 info->set_mark();
1984 }
1985 }
1986
1987 // traverse backward from target, along edges found in BFS
1988 void PrintBFS::select_all_paths() {
1989 int pos = 0;
1990 GrowableArray<const Node*> backtrace;
1991 // start from target
1992 backtrace.push(_target);
1993 find_info(_target)->set_mark();
1994 // traverse backward
1995 while (pos < backtrace.length()) {
1996 const Node* n = backtrace.at(pos++);
1997 Info* info = find_info(n);
1998 for (int i = 0; i < info->edge_bwd.length(); i++) {
1999 // all backward edges
2000 const Node* back = info->edge_bwd.at(i);
2001 Info* back_info = find_info(back);
2002 if (!back_info->is_marked()) {
2003 // not yet found this on way back.
2004 back_info->set_distance_from_target(info->distance_from_target() + 1);
2005 if (back_info->distance_from_target() + back_info->distance() <= _max_distance) {
2006 // total distance is small enough
2007 back_info->set_mark();
2008 backtrace.push(back);
2009 }
2010 }
2011 }
2012 }
2013 }
2014
2015 void PrintBFS::select_shortest_path() {
2016 const Node* current = _target;
2017 while (true) {
2018 Info* info = find_info(current);
2019 info->set_mark();
2020 if (current == _start) {
2021 break;
2022 }
2023 // first edge -> leads us one step closer to _start
2024 current = info->edge_bwd.at(0);
2025 }
2026 }
2027
2028 // go through worklist in desired order, put the marked ones in print list
2029 void PrintBFS::sort() {
2030 if (_traverse_inputs && !_traverse_outputs) {
2031 // reverse order
2032 for (int i = _worklist.length() - 1; i >= 0; i--) {
2033 const Node* n = _worklist.at(i);
2034 Info* info = find_info(n);
2035 if (info->is_marked()) {
2036 _print_list.push(n);
2037 }
2038 }
2039 } else {
2040 // same order as worklist
2041 for (int i = 0; i < _worklist.length(); i++) {
2042 const Node* n = _worklist.at(i);
2043 Info* info = find_info(n);
2044 if (info->is_marked()) {
2045 _print_list.push(n);
2046 }
2047 }
2048 }
2049 if (_sort_idx) {
2050 _print_list.sort(node_idx_cmp);
2051 }
2052 }
2053
2054 // go through printlist and print
2055 void PrintBFS::print() {
2056 if (_print_list.length() > 0 ) {
2057 print_header();
2058 for (int i = 0; i < _print_list.length(); i++) {
2059 const Node* n = _print_list.at(i);
2060 print_node(n);
2061 }
2062 if (_print_igv) {
2063 Compile* C = Compile::current();
2064 C->init_igv();
2065 C->igv_print_graph_to_network(nullptr, _print_list, _frame);
2066 }
2067 } else {
2068 _output->print_cr("No nodes to print.");
2069 }
2070 }
2071
2072 void PrintBFS::print_options_help(bool print_examples) {
2073 _output->print_cr("Usage: node->dump_bfs(int max_distance, Node* target, char* options)");
2074 _output->print_cr("");
2075 _output->print_cr("Use cases:");
2076 _output->print_cr(" BFS traversal: no target required");
2077 _output->print_cr(" shortest path: set target");
2078 _output->print_cr(" all paths: set target and put 'A' in options");
2079 _output->print_cr(" detect loop: subcase of all paths, have start==target");
2080 _output->print_cr("");
2081 _output->print_cr("Arguments:");
2082 _output->print_cr(" this/start: staring point of BFS");
2083 _output->print_cr(" target:");
2084 _output->print_cr(" if null: simple BFS");
2085 _output->print_cr(" else: shortest path or all paths between this/start and target");
2086 _output->print_cr(" options:");
2087 _output->print_cr(" if null: same as \"cdmox@B\"");
2088 _output->print_cr(" else: use combination of following characters");
2089 _output->print_cr(" h: display this help info");
2090 _output->print_cr(" H: display this help info, with examples");
2091 _output->print_cr(" +: traverse in-edges (on if neither + nor -)");
2092 _output->print_cr(" -: traverse out-edges");
2093 _output->print_cr(" c: visit control nodes");
2094 _output->print_cr(" d: visit data nodes");
2095 _output->print_cr(" m: visit memory nodes");
2096 _output->print_cr(" o: visit other nodes");
2097 _output->print_cr(" x: visit mixed nodes");
2098 _output->print_cr(" C: boundary control nodes");
2099 _output->print_cr(" D: boundary data nodes");
2100 _output->print_cr(" M: boundary memory nodes");
2101 _output->print_cr(" O: boundary other nodes");
2102 _output->print_cr(" X: boundary mixed nodes");
2103 _output->print_cr(" #: display node category in color (not supported in all terminals)");
2104 _output->print_cr(" S: sort displayed nodes by node idx");
2105 _output->print_cr(" A: all paths (not just shortest path to target)");
2106 _output->print_cr(" @: print old nodes - before matching (if available)");
2107 _output->print_cr(" B: print scheduling blocks (if available)");
2108 _output->print_cr(" $: dump only, no header, no other columns");
2109 _output->print_cr(" !: show nodes on IGV (sent over network stream)");
2110 _output->print_cr(" (use preferably with dump_bfs(int, Node*, char*, void*, void*, void*)");
2111 _output->print_cr(" to produce a C2 stack trace along with the graph dump, see examples below)");
2112 _output->print_cr("");
2113 _output->print_cr("recursively follow edges to nodes with permitted visit types,");
2114 _output->print_cr("on the boundary additionally display nodes allowed in boundary types");
2115 _output->print_cr("Note: the categories can be overlapping. For example a mixed node");
2116 _output->print_cr(" can contain control and memory output. Some from the other");
2117 _output->print_cr(" category are also control (Halt, Return, etc).");
2118 _output->print_cr("");
2119 _output->print_cr("output columns:");
2120 _output->print_cr(" dist: BFS distance to this/start");
2121 _output->print_cr(" apd: all paths distance (d_outputart + d_target)");
2122 _output->print_cr(" block: block identifier, based on _pre_order");
2123 _output->print_cr(" head: first node in block");
2124 _output->print_cr(" idom: head node of idom block");
2125 _output->print_cr(" depth: depth of block (_dom_depth)");
2126 _output->print_cr(" old: old IR node - before matching");
2127 _output->print_cr(" dump: node->dump()");
2128 _output->print_cr("");
2129 _output->print_cr("Note: if none of the \"cmdxo\" characters are in the options string");
2130 _output->print_cr(" then we set all of them.");
2131 _output->print_cr(" This allows for short strings like \"#\" for colored input traversal");
2132 _output->print_cr(" or \"-#\" for colored output traversal.");
2133 if (print_examples) {
2134 _output->print_cr("");
2135 _output->print_cr("Examples:");
2136 _output->print_cr(" if->dump_bfs(10, 0, \"+cxo\")");
2137 _output->print_cr(" starting at some if node, traverse inputs recursively");
2138 _output->print_cr(" only along control (mixed and other can also be control)");
2139 _output->print_cr(" phi->dump_bfs(5, 0, \"-dxo\")");
2140 _output->print_cr(" starting at phi node, traverse outputs recursively");
2141 _output->print_cr(" only along data (mixed and other can also have data flow)");
2142 _output->print_cr(" find_node(385)->dump_bfs(3, 0, \"cdmox+#@B\")");
2143 _output->print_cr(" find inputs of node 385, up to 3 nodes up (+)");
2144 _output->print_cr(" traverse all nodes (cdmox), use colors (#)");
2145 _output->print_cr(" display old nodes and blocks, if they exist");
2146 _output->print_cr(" useful call to start with");
2147 _output->print_cr(" find_node(102)->dump_bfs(10, 0, \"dCDMOX-\")");
2148 _output->print_cr(" find non-data dependencies of a data node");
2149 _output->print_cr(" follow data node outputs until we find another category");
2150 _output->print_cr(" node as the boundary");
2151 _output->print_cr(" x->dump_bfs(10, y, 0)");
2152 _output->print_cr(" find shortest path from x to y, along any edge or node");
2153 _output->print_cr(" will not find a path if it is longer than 10");
2154 _output->print_cr(" useful to find how x and y are related");
2155 _output->print_cr(" find_node(741)->dump_bfs(20, find_node(746), \"c+\")");
2156 _output->print_cr(" find shortest control path between two nodes");
2157 _output->print_cr(" find_node(741)->dump_bfs(8, find_node(746), \"cdmox+A\")");
2158 _output->print_cr(" find all paths (A) between two nodes of length at most 8");
2159 _output->print_cr(" find_node(741)->dump_bfs(7, find_node(741), \"c+A\")");
2160 _output->print_cr(" find all control loops for this node");
2161 _output->print_cr(" find_node(741)->dump_bfs(7, find_node(741), \"c+A!\", $sp, $fp, $pc)");
2162 _output->print_cr(" same as above, but printing the resulting subgraph");
2163 _output->print_cr(" along with a C2 stack trace on IGV");
2164 }
2165 }
2166
2167 bool PrintBFS::parse_options() {
2168 if (_options == nullptr) {
2169 _options = "cdmox@B"; // default options
2170 }
2171 size_t len = strlen(_options);
2172 for (size_t i = 0; i < len; i++) {
2173 switch (_options[i]) {
2174 case '+':
2175 _traverse_inputs = true;
2176 break;
2177 case '-':
2178 _traverse_outputs = true;
2179 break;
2180 case 'c':
2181 _filter_visit._control = true;
2182 break;
2183 case 'm':
2184 _filter_visit._memory = true;
2185 break;
2186 case 'd':
2187 _filter_visit._data = true;
2188 break;
2189 case 'x':
2190 _filter_visit._mixed = true;
2191 break;
2192 case 'o':
2193 _filter_visit._other = true;
2194 break;
2195 case 'C':
2196 _filter_boundary._control = true;
2197 break;
2198 case 'M':
2199 _filter_boundary._memory = true;
2200 break;
2201 case 'D':
2202 _filter_boundary._data = true;
2203 break;
2204 case 'X':
2205 _filter_boundary._mixed = true;
2206 break;
2207 case 'O':
2208 _filter_boundary._other = true;
2209 break;
2210 case 'S':
2211 _sort_idx = true;
2212 break;
2213 case 'A':
2214 _all_paths = true;
2215 break;
2216 case '#':
2217 _use_color = true;
2218 break;
2219 case 'B':
2220 _print_blocks = true;
2221 break;
2222 case '@':
2223 _print_old = true;
2224 break;
2225 case '$':
2226 _dump_only = true;
2227 break;
2228 case '!':
2229 _print_igv = true;
2230 break;
2231 case 'h':
2232 print_options_help(false);
2233 return false;
2234 case 'H':
2235 print_options_help(true);
2236 return false;
2237 default:
2238 _output->print_cr("dump_bfs: Unrecognized option \'%c\'", _options[i]);
2239 _output->print_cr("for help, run: find_node(0)->dump_bfs(0,0,\"H\")");
2240 return false;
2241 }
2242 }
2243 if (!_traverse_inputs && !_traverse_outputs) {
2244 _traverse_inputs = true;
2245 }
2246 if (_filter_visit.is_empty()) {
2247 _filter_visit.set_all();
2248 }
2249 Compile* C = Compile::current();
2250 _print_old &= (C->matcher() != nullptr); // only show old if there are new
2251 _print_blocks &= (C->cfg() != nullptr); // only show blocks if available
2252 return true;
2253 }
2254
2255 void PrintBFS::DumpConfigColored::pre_dump(outputStream* st, const Node* n) {
2256 if (!_bfs->_use_color) {
2257 return;
2258 }
2259 Info* info = _bfs->find_info(n);
2260 if (info == nullptr || !info->is_marked()) {
2261 return;
2262 }
2263
2264 const Type* t = n->bottom_type();
2265 switch (t->category()) {
2266 case Type::Category::Data:
2267 st->print("\u001b[34m");
2268 break;
2269 case Type::Category::Memory:
2270 st->print("\u001b[32m");
2271 break;
2272 case Type::Category::Mixed:
2273 st->print("\u001b[35m");
2274 break;
2275 case Type::Category::Control:
2276 st->print("\u001b[31m");
2277 break;
2278 case Type::Category::Other:
2279 st->print("\u001b[33m");
2280 break;
2281 case Type::Category::Undef:
2282 n->dump();
2283 assert(false, "category undef ??");
2284 break;
2285 default:
2286 n->dump();
2287 assert(false, "not covered");
2288 break;
2289 }
2290 }
2291
2292 void PrintBFS::DumpConfigColored::post_dump(outputStream* st) {
2293 if (!_bfs->_use_color) {
2294 return;
2295 }
2296 st->print("\u001b[0m"); // white
2297 }
2298
2299 Node* PrintBFS::old_node(const Node* n) {
2300 Compile* C = Compile::current();
2301 if (C->matcher() == nullptr || !C->node_arena()->contains(n)) {
2302 return (Node*)nullptr;
2303 } else {
2304 return C->matcher()->find_old_node(n);
2305 }
2306 }
2307
2308 void PrintBFS::print_node_idx(const Node* n) {
2309 Compile* C = Compile::current();
2310 char buf[30];
2311 if (n == nullptr) {
2312 os::snprintf_checked(buf, sizeof(buf), "_"); // null
2313 } else if (C->node_arena()->contains(n)) {
2314 os::snprintf_checked(buf, sizeof(buf), "%d", n->_idx); // new node
2315 } else {
2316 os::snprintf_checked(buf, sizeof(buf), "o%d", n->_idx); // old node
2317 }
2318 _output->print("%6s", buf);
2319 }
2320
2321 void PrintBFS::print_block_id(const Block* b) {
2322 Compile* C = Compile::current();
2323 char buf[30];
2324 os::snprintf_checked(buf, sizeof(buf), "B%d", b->_pre_order);
2325 _output->print("%7s", buf);
2326 }
2327
2328 void PrintBFS::print_node_block(const Node* n) {
2329 Compile* C = Compile::current();
2330 Block* b = C->node_arena()->contains(n)
2331 ? C->cfg()->get_block_for_node(n)
2332 : nullptr; // guard against old nodes
2333 if (b == nullptr) {
2334 _output->print(" _"); // Block
2335 _output->print(" _"); // head
2336 _output->print(" _"); // idom
2337 _output->print(" _"); // depth
2338 } else {
2339 print_block_id(b);
2340 print_node_idx(b->head());
2341 if (b->_idom) {
2342 print_node_idx(b->_idom->head());
2343 } else {
2344 _output->print(" _"); // idom
2345 }
2346 _output->print("%6d ", b->_dom_depth);
2347 }
2348 }
2349
2350 // filter, and add to worklist, add info, note traversal edges
2351 void PrintBFS::maybe_traverse(const Node* src, const Node* dst) {
2352 if (dst != nullptr &&
2353 (_filter_visit.accepts(dst) ||
2354 _filter_boundary.accepts(dst) ||
2355 dst == _start)) { // correct category or start?
2356 if (find_info(dst) == nullptr) {
2357 // never visited - set up info
2358 _worklist.push(dst);
2359 int d = 0;
2360 if (dst != _start) {
2361 d = find_info(src)->distance() + 1;
2362 }
2363 make_info(dst, d);
2364 }
2365 if (src != dst) {
2366 // traversal edges useful during select
2367 find_info(dst)->edge_bwd.push(src);
2368 }
2369 }
2370 }
2371
2372 void PrintBFS::print_header() const {
2373 if (_dump_only) {
2374 return; // no header in dump only mode
2375 }
2376 _output->print("dist"); // distance
2377 if (_all_paths) {
2378 _output->print(" apd"); // all paths distance
2379 }
2380 if (_print_blocks) {
2381 _output->print(" [block head idom depth]"); // block
2382 }
2383 if (_print_old) {
2384 _output->print(" old"); // old node
2385 }
2386 _output->print(" dump\n"); // node dump
2387 _output->print_cr("---------------------------------------------");
2388 }
2389
2390 void PrintBFS::print_node(const Node* n) {
2391 if (_dump_only) {
2392 n->dump("\n", false, _output, &_dcc);
2393 return;
2394 }
2395 _output->print("%4d", find_info(n)->distance());// distance
2396 if (_all_paths) {
2397 Info* info = find_info(n);
2398 int apd = info->distance() + info->distance_from_target();
2399 _output->print("%4d", apd); // all paths distance
2400 }
2401 if (_print_blocks) {
2402 print_node_block(n); // block
2403 }
2404 if (_print_old) {
2405 print_node_idx(old_node(n)); // old node
2406 }
2407 _output->print(" ");
2408 n->dump("\n", false, _output, &_dcc); // node dump
2409 }
2410
2411 //------------------------------dump_bfs--------------------------------------
2412 // Call this from debugger
2413 // Useful for BFS traversal, shortest path, all path, loop detection, etc
2414 // Designed to be more readable, and provide additional info
2415 // To find all options, run:
2416 // find_node(0)->dump_bfs(0,0,"H")
2417 void Node::dump_bfs(const int max_distance, Node* target, const char* options) const {
2418 dump_bfs(max_distance, target, options, tty);
2419 }
2420
2421 // Used to dump to stream.
2422 void Node::dump_bfs(const int max_distance, Node* target, const char* options, outputStream* st, const frame* fr) const {
2423 PrintBFS bfs(this, max_distance, target, options, st, fr);
2424 bfs.run();
2425 }
2426
2427 // Call this from debugger, with default arguments
2428 void Node::dump_bfs(const int max_distance) const {
2429 dump_bfs(max_distance, nullptr, nullptr);
2430 }
2431
2432 // Call this from debugger, with stack handling register arguments for IGV dumps.
2433 // Example: p find_node(741)->dump_bfs(7, find_node(741), "c+A!", $sp, $fp, $pc).
2434 void Node::dump_bfs(const int max_distance, Node* target, const char* options, void* sp, void* fp, void* pc) const {
2435 frame fr(sp, fp, pc);
2436 dump_bfs(max_distance, target, options, tty, &fr);
2437 }
2438
2439 // -----------------------------dump_idx---------------------------------------
2440 void Node::dump_idx(bool align, outputStream* st, DumpConfig* dc) const {
2441 if (dc != nullptr) {
2442 dc->pre_dump(st, this);
2443 }
2444 Compile* C = Compile::current();
2445 bool is_new = C->node_arena()->contains(this);
2446 if (align) { // print prefix empty spaces$
2447 // +1 for leading digit, +1 for "o"
2448 uint max_width = (C->unique() == 0 ? 0 : static_cast<uint>(log10(static_cast<double>(C->unique())))) + 2;
2449 // +1 for leading digit, maybe +1 for "o"
2450 uint width = (_idx == 0 ? 0 : static_cast<uint>(log10(static_cast<double>(_idx)))) + 1 + (is_new ? 0 : 1);
2451 while (max_width > width) {
2452 st->print(" ");
2453 width++;
2454 }
2455 }
2456 if (!is_new) {
2457 st->print("o");
2458 }
2459 st->print("%d", _idx);
2460 if (dc != nullptr) {
2461 dc->post_dump(st);
2462 }
2463 }
2464
2465 // -----------------------------dump_name--------------------------------------
2466 void Node::dump_name(outputStream* st, DumpConfig* dc) const {
2467 if (dc != nullptr) {
2468 dc->pre_dump(st, this);
2469 }
2470 st->print("%s", Name());
2471 if (dc != nullptr) {
2472 dc->post_dump(st);
2473 }
2474 }
2475
2476 // -----------------------------Name-------------------------------------------
2477 extern const char *NodeClassNames[];
2478 const char *Node::Name() const { return NodeClassNames[Opcode()]; }
2479
2480 static bool is_disconnected(const Node* n) {
2481 for (uint i = 0; i < n->req(); i++) {
2482 if (n->in(i) != nullptr) return false;
2483 }
2484 return true;
2485 }
2486
2487 #ifdef ASSERT
2488 void Node::dump_orig(outputStream *st, bool print_key) const {
2489 Compile* C = Compile::current();
2490 Node* orig = _debug_orig;
2491 if (not_a_node(orig)) orig = nullptr;
2492 if (orig != nullptr && !C->node_arena()->contains(orig)) orig = nullptr;
2493 if (orig == nullptr) return;
2494 if (print_key) {
2495 st->print(" !orig=");
2496 }
2497 Node* fast = orig->debug_orig(); // tortoise & hare algorithm to detect loops
2498 if (not_a_node(fast)) fast = nullptr;
2499 while (orig != nullptr) {
2500 bool discon = is_disconnected(orig); // if discon, print [123] else 123
2501 if (discon) st->print("[");
2502 if (!Compile::current()->node_arena()->contains(orig))
2503 st->print("o");
2504 st->print("%d", orig->_idx);
2505 if (discon) st->print("]");
2506 orig = orig->debug_orig();
2507 if (not_a_node(orig)) orig = nullptr;
2508 if (orig != nullptr && !C->node_arena()->contains(orig)) orig = nullptr;
2509 if (orig != nullptr) st->print(",");
2510 if (fast != nullptr) {
2511 // Step fast twice for each single step of orig:
2512 fast = fast->debug_orig();
2513 if (not_a_node(fast)) fast = nullptr;
2514 if (fast != nullptr && fast != orig) {
2515 fast = fast->debug_orig();
2516 if (not_a_node(fast)) fast = nullptr;
2517 }
2518 if (fast == orig) {
2519 st->print("...");
2520 break;
2521 }
2522 }
2523 }
2524 }
2525
2526 void Node::set_debug_orig(Node* orig) {
2527 _debug_orig = orig;
2528 if (BreakAtNode == 0) return;
2529 if (not_a_node(orig)) orig = nullptr;
2530 int trip = 10;
2531 while (orig != nullptr) {
2532 if (orig->debug_idx() == BreakAtNode || (uintx)orig->_idx == BreakAtNode) {
2533 tty->print_cr("BreakAtNode: _idx=%d _debug_idx=" UINT64_FORMAT " orig._idx=%d orig._debug_idx=" UINT64_FORMAT,
2534 this->_idx, this->debug_idx(), orig->_idx, orig->debug_idx());
2535 BREAKPOINT;
2536 }
2537 orig = orig->debug_orig();
2538 if (not_a_node(orig)) orig = nullptr;
2539 if (trip-- <= 0) break;
2540 }
2541 }
2542 #endif //ASSERT
2543
2544 //------------------------------dump------------------------------------------
2545 // Dump a Node
2546 void Node::dump(const char* suffix, bool mark, outputStream* st, DumpConfig* dc) const {
2547 Compile* C = Compile::current();
2548 bool is_new = C->node_arena()->contains(this);
2549 C->_in_dump_cnt++;
2550
2551 // idx mark name ===
2552 dump_idx(true, st, dc);
2553 st->print(mark ? " >" : " ");
2554 dump_name(st, dc);
2555 st->print(" === ");
2556
2557 // Dump the required and precedence inputs
2558 dump_req(st, dc);
2559 dump_prec(st, dc);
2560 // Dump the outputs
2561 dump_out(st, dc);
2562
2563 if (is_disconnected(this)) {
2564 #ifdef ASSERT
2565 st->print(" [" UINT64_FORMAT "]", debug_idx());
2566 dump_orig(st);
2567 #endif
2568 st->cr();
2569 C->_in_dump_cnt--;
2570 return; // don't process dead nodes
2571 }
2572
2573 if (C->clone_map().value(_idx) != 0) {
2574 C->clone_map().dump(_idx, st);
2575 }
2576 // Dump node-specific info
2577 dump_spec(st);
2578 #ifdef ASSERT
2579 // Dump the non-reset _debug_idx
2580 if (Verbose && WizardMode) {
2581 st->print(" [" UINT64_FORMAT "]", debug_idx());
2582 }
2583 #endif
2584
2585 const Type *t = bottom_type();
2586
2587 if (t != nullptr && (t->isa_instptr() || t->isa_instklassptr())) {
2588 const TypeInstPtr *toop = t->isa_instptr();
2589 const TypeInstKlassPtr *tkls = t->isa_instklassptr();
2590 if (toop) {
2591 st->print(" Oop:");
2592 } else if (tkls) {
2593 st->print(" Klass:");
2594 }
2595 t->dump_on(st);
2596 } else if (t == Type::MEMORY) {
2597 st->print(" Memory:");
2598 MemNode::dump_adr_type(this, adr_type(), st);
2599 } else if (Verbose || WizardMode) {
2600 st->print(" Type:");
2601 if (t) {
2602 t->dump_on(st);
2603 } else {
2604 st->print("no type");
2605 }
2606 } else if (t->isa_vect() && this->is_MachSpillCopy()) {
2607 // Dump MachSpillcopy vector type.
2608 t->dump_on(st);
2609 }
2610 if (is_new) {
2611 DEBUG_ONLY(dump_orig(st));
2612 Node_Notes* nn = C->node_notes_at(_idx);
2613 if (nn != nullptr && !nn->is_clear()) {
2614 if (nn->jvms() != nullptr) {
2615 st->print(" !jvms:");
2616 nn->jvms()->dump_spec(st);
2617 }
2618 }
2619 }
2620 if (suffix) st->print("%s", suffix);
2621 C->_in_dump_cnt--;
2622 }
2623
2624 // call from debugger: dump node to tty with newline
2625 void Node::dump() const {
2626 dump("\n");
2627 }
2628
2629 //------------------------------dump_req--------------------------------------
2630 void Node::dump_req(outputStream* st, DumpConfig* dc) const {
2631 // Dump the required input edges
2632 for (uint i = 0; i < req(); i++) { // For all required inputs
2633 Node* d = in(i);
2634 if (d == nullptr) {
2635 st->print("_ ");
2636 } else if (not_a_node(d)) {
2637 st->print("not_a_node "); // uninitialized, sentinel, garbage, etc.
2638 } else {
2639 d->dump_idx(false, st, dc);
2640 st->print(" ");
2641 }
2642 }
2643 }
2644
2645
2646 //------------------------------dump_prec-------------------------------------
2647 void Node::dump_prec(outputStream* st, DumpConfig* dc) const {
2648 // Dump the precedence edges
2649 int any_prec = 0;
2650 for (uint i = req(); i < len(); i++) { // For all precedence inputs
2651 Node* p = in(i);
2652 if (p != nullptr) {
2653 if (!any_prec++) st->print(" |");
2654 if (not_a_node(p)) { st->print("not_a_node "); continue; }
2655 p->dump_idx(false, st, dc);
2656 st->print(" ");
2657 }
2658 }
2659 }
2660
2661 //------------------------------dump_out--------------------------------------
2662 void Node::dump_out(outputStream* st, DumpConfig* dc) const {
2663 // Delimit the output edges
2664 st->print(" [[ ");
2665 // Dump the output edges
2666 for (uint i = 0; i < _outcnt; i++) { // For all outputs
2667 Node* u = _out[i];
2668 if (u == nullptr) {
2669 st->print("_ ");
2670 } else if (not_a_node(u)) {
2671 st->print("not_a_node ");
2672 } else {
2673 u->dump_idx(false, st, dc);
2674 st->print(" ");
2675 }
2676 }
2677 st->print("]] ");
2678 }
2679
2680 //------------------------------dump-------------------------------------------
2681 // call from debugger: dump Node's inputs (or outputs if d negative)
2682 void Node::dump(int d) const {
2683 dump_bfs(abs(d), nullptr, (d > 0) ? "+$" : "-$");
2684 }
2685
2686 //------------------------------dump_ctrl--------------------------------------
2687 // call from debugger: dump Node's control inputs (or outputs if d negative)
2688 void Node::dump_ctrl(int d) const {
2689 dump_bfs(abs(d), nullptr, (d > 0) ? "+$c" : "-$c");
2690 }
2691
2692 //-----------------------------dump_compact------------------------------------
2693 void Node::dump_comp() const {
2694 this->dump_comp("\n");
2695 }
2696
2697 //-----------------------------dump_compact------------------------------------
2698 // Dump a Node in compact representation, i.e., just print its name and index.
2699 // Nodes can specify additional specifics to print in compact representation by
2700 // implementing dump_compact_spec.
2701 void Node::dump_comp(const char* suffix, outputStream *st) const {
2702 Compile* C = Compile::current();
2703 C->_in_dump_cnt++;
2704 st->print("%s(%d)", Name(), _idx);
2705 this->dump_compact_spec(st);
2706 if (suffix) {
2707 st->print("%s", suffix);
2708 }
2709 C->_in_dump_cnt--;
2710 }
2711
2712 // VERIFICATION CODE
2713 // Verify all nodes if verify_depth is negative
2714 void Node::verify(int verify_depth, VectorSet& visited, Node_List& worklist) {
2715 assert(verify_depth != 0, "depth should not be 0");
2716 Compile* C = Compile::current();
2717 uint last_index_on_current_depth = worklist.size() - 1;
2718 verify_depth--; // Visiting the first node on depth 1
2719 // Only add nodes to worklist if verify_depth is negative (visit all nodes) or greater than 0
2720 bool add_to_worklist = verify_depth != 0;
2721
2722 for (uint list_index = 0; list_index < worklist.size(); list_index++) {
2723 Node* n = worklist[list_index];
2724
2725 if (n->is_Con() && n->bottom_type() == Type::TOP) {
2726 if (C->cached_top_node() == nullptr) {
2727 C->set_cached_top_node((Node*)n);
2728 }
2729 assert(C->cached_top_node() == n, "TOP node must be unique");
2730 }
2731
2732 uint in_len = n->len();
2733 for (uint i = 0; i < in_len; i++) {
2734 Node* x = n->_in[i];
2735 if (!x || x->is_top()) {
2736 continue;
2737 }
2738
2739 // Verify my input has a def-use edge to me
2740 // Count use-def edges from n to x
2741 int cnt = 1;
2742 for (uint j = 0; j < i; j++) {
2743 if (n->_in[j] == x) {
2744 cnt++;
2745 break;
2746 }
2747 }
2748 if (cnt == 2) {
2749 // x is already checked as n's previous input, skip its duplicated def-use count checking
2750 continue;
2751 }
2752 for (uint j = i + 1; j < in_len; j++) {
2753 if (n->_in[j] == x) {
2754 cnt++;
2755 }
2756 }
2757
2758 // Count def-use edges from x to n
2759 uint max = x->_outcnt;
2760 for (uint k = 0; k < max; k++) {
2761 if (x->_out[k] == n) {
2762 cnt--;
2763 }
2764 }
2765 assert(cnt == 0, "mismatched def-use edge counts");
2766
2767 if (add_to_worklist && !visited.test_set(x->_idx)) {
2768 worklist.push(x);
2769 }
2770 }
2771
2772 if (verify_depth > 0 && list_index == last_index_on_current_depth) {
2773 // All nodes on this depth were processed and its inputs are on the worklist. Decrement verify_depth and
2774 // store the current last list index which is the last node in the list with the new depth. All nodes
2775 // added afterwards will have a new depth again. Stop adding new nodes if depth limit is reached (=0).
2776 verify_depth--;
2777 if (verify_depth == 0) {
2778 add_to_worklist = false;
2779 }
2780 last_index_on_current_depth = worklist.size() - 1;
2781 }
2782 }
2783 }
2784 #endif // not PRODUCT
2785
2786 //------------------------------Registers--------------------------------------
2787 // Do we Match on this edge index or not? Generally false for Control
2788 // and true for everything else. Weird for calls & returns.
2789 uint Node::match_edge(uint idx) const {
2790 return idx; // True for other than index 0 (control)
2791 }
2792
2793 // Register classes are defined for specific machines
2794 const RegMask &Node::out_RegMask() const {
2795 ShouldNotCallThis();
2796 return RegMask::EMPTY;
2797 }
2798
2799 const RegMask &Node::in_RegMask(uint) const {
2800 ShouldNotCallThis();
2801 return RegMask::EMPTY;
2802 }
2803
2804 void Node_Array::grow(uint i) {
2805 assert(i >= _max, "Should have been checked before, use maybe_grow?");
2806 assert(_max > 0, "invariant");
2807 uint old = _max;
2808 _max = next_power_of_2(i);
2809 _nodes = (Node**)_a->Arealloc( _nodes, old*sizeof(Node*),_max*sizeof(Node*));
2810 Copy::zero_to_bytes( &_nodes[old], (_max-old)*sizeof(Node*) );
2811 }
2812
2813 void Node_Array::insert(uint i, Node* n) {
2814 if (_nodes[_max - 1]) {
2815 grow(_max);
2816 }
2817 Copy::conjoint_words_to_higher((HeapWord*)&_nodes[i], (HeapWord*)&_nodes[i + 1], ((_max - i - 1) * sizeof(Node*)));
2818 _nodes[i] = n;
2819 }
2820
2821 void Node_Array::remove(uint i) {
2822 Copy::conjoint_words_to_lower((HeapWord*)&_nodes[i + 1], (HeapWord*)&_nodes[i], ((_max - i - 1) * sizeof(Node*)));
2823 _nodes[_max - 1] = nullptr;
2824 }
2825
2826 void Node_Array::dump() const {
2827 #ifndef PRODUCT
2828 for (uint i = 0; i < _max; i++) {
2829 Node* nn = _nodes[i];
2830 if (nn != nullptr) {
2831 tty->print("%5d--> ",i); nn->dump();
2832 }
2833 }
2834 #endif
2835 }
2836
2837 //--------------------------is_iteratively_computed------------------------------
2838 // Operation appears to be iteratively computed (such as an induction variable)
2839 // It is possible for this operation to return false for a loop-varying
2840 // value, if it appears (by local graph inspection) to be computed by a simple conditional.
2841 bool Node::is_iteratively_computed() {
2842 if (ideal_reg()) { // does operation have a result register?
2843 for (uint i = 1; i < req(); i++) {
2844 Node* n = in(i);
2845 if (n != nullptr && n->is_Phi()) {
2846 for (uint j = 1; j < n->req(); j++) {
2847 if (n->in(j) == this) {
2848 return true;
2849 }
2850 }
2851 }
2852 }
2853 }
2854 return false;
2855 }
2856
2857 //--------------------------find_similar------------------------------
2858 // Return a node with opcode "opc" and same inputs as "this" if one can
2859 // be found; Otherwise return null;
2860 Node* Node::find_similar(int opc) {
2861 if (req() >= 2) {
2862 Node* def = in(1);
2863 if (def && def->outcnt() >= 2) {
2864 for (DUIterator_Fast dmax, i = def->fast_outs(dmax); i < dmax; i++) {
2865 Node* use = def->fast_out(i);
2866 if (use != this &&
2867 use->Opcode() == opc &&
2868 use->req() == req()) {
2869 uint j;
2870 for (j = 0; j < use->req(); j++) {
2871 if (use->in(j) != in(j)) {
2872 break;
2873 }
2874 }
2875 if (j == use->req()) {
2876 return use;
2877 }
2878 }
2879 }
2880 }
2881 }
2882 return nullptr;
2883 }
2884
2885
2886 //--------------------------unique_ctrl_out_or_null-------------------------
2887 // Return the unique control out if only one. Null if none or more than one.
2888 Node* Node::unique_ctrl_out_or_null() const {
2889 Node* found = nullptr;
2890 for (uint i = 0; i < outcnt(); i++) {
2891 Node* use = raw_out(i);
2892 if (use->is_CFG() && use != this) {
2893 if (found != nullptr) {
2894 return nullptr;
2895 }
2896 found = use;
2897 }
2898 }
2899 return found;
2900 }
2901
2902 //--------------------------unique_ctrl_out------------------------------
2903 // Return the unique control out. Asserts if none or more than one control out.
2904 Node* Node::unique_ctrl_out() const {
2905 Node* ctrl = unique_ctrl_out_or_null();
2906 assert(ctrl != nullptr, "control out is assumed to be unique");
2907 return ctrl;
2908 }
2909
2910 void Node::ensure_control_or_add_prec(Node* c) {
2911 if (in(0) == nullptr) {
2912 set_req(0, c);
2913 } else if (in(0) != c) {
2914 add_prec(c);
2915 }
2916 }
2917
2918 void Node::add_prec_from(Node* n) {
2919 for (uint i = n->req(); i < n->len(); i++) {
2920 Node* prec = n->in(i);
2921 if (prec != nullptr) {
2922 add_prec(prec);
2923 }
2924 }
2925 }
2926
2927 bool Node::is_dead_loop_safe() const {
2928 if (is_Phi()) {
2929 return true;
2930 }
2931 if (is_Proj() && in(0) == nullptr) {
2932 return true;
2933 }
2934 if ((_flags & (Flag_is_dead_loop_safe | Flag_is_Con)) != 0) {
2935 if (!is_Proj()) {
2936 return true;
2937 }
2938 if (in(0)->is_Allocate()) {
2939 return false;
2940 }
2941 // MemNode::can_see_stored_value() peeks through the boxing call
2942 if (in(0)->is_CallStaticJava() && in(0)->as_CallStaticJava()->is_boxing_method()) {
2943 return false;
2944 }
2945 return true;
2946 }
2947 return false;
2948 }
2949
2950 bool Node::is_div_or_mod(BasicType bt) const { return Opcode() == Op_Div(bt) || Opcode() == Op_Mod(bt) ||
2951 Opcode() == Op_UDiv(bt) || Opcode() == Op_UMod(bt); }
2952
2953 // `maybe_pure_function` is assumed to be the input of `this`. This is a bit redundant,
2954 // but we already have and need maybe_pure_function in all the call sites, so
2955 // it makes it obvious that the `maybe_pure_function` is the same node as in the caller,
2956 // while it takes more thinking to realize that a locally computed in(0) must be equal to
2957 // the local in the caller.
2958 bool Node::is_data_proj_of_pure_function(const Node* maybe_pure_function) const {
2959 return Opcode() == Op_Proj && as_Proj()->_con == TypeFunc::Parms && maybe_pure_function->is_CallLeafPure();
2960 }
2961
2962 //=============================================================================
2963 //------------------------------yank-------------------------------------------
2964 // Find and remove
2965 void Node_List::yank( Node *n ) {
2966 uint i;
2967 for (i = 0; i < _cnt; i++) {
2968 if (_nodes[i] == n) {
2969 break;
2970 }
2971 }
2972
2973 if (i < _cnt) {
2974 _nodes[i] = _nodes[--_cnt];
2975 }
2976 }
2977
2978 //------------------------------dump-------------------------------------------
2979 void Node_List::dump() const {
2980 #ifndef PRODUCT
2981 for (uint i = 0; i < _cnt; i++) {
2982 if (_nodes[i]) {
2983 tty->print("%5d--> ", i);
2984 _nodes[i]->dump();
2985 }
2986 }
2987 #endif
2988 }
2989
2990 void Node_List::dump_simple() const {
2991 #ifndef PRODUCT
2992 for (uint i = 0; i < _cnt; i++) {
2993 if( _nodes[i] ) {
2994 tty->print(" %d", _nodes[i]->_idx);
2995 } else {
2996 tty->print(" null");
2997 }
2998 }
2999 #endif
3000 }
3001
3002 //=============================================================================
3003 //------------------------------remove-----------------------------------------
3004 void Unique_Node_List::remove(Node* n) {
3005 if (_in_worklist.test(n->_idx)) {
3006 for (uint i = 0; i < size(); i++) {
3007 if (_nodes[i] == n) {
3008 map(i, Node_List::pop());
3009 _in_worklist.remove(n->_idx);
3010 return;
3011 }
3012 }
3013 ShouldNotReachHere();
3014 }
3015 }
3016
3017 //-----------------------remove_useless_nodes----------------------------------
3018 // Remove useless nodes from worklist
3019 void Unique_Node_List::remove_useless_nodes(VectorSet &useful) {
3020 for (uint i = 0; i < size(); ++i) {
3021 Node *n = at(i);
3022 assert( n != nullptr, "Did not expect null entries in worklist");
3023 if (!useful.test(n->_idx)) {
3024 _in_worklist.remove(n->_idx);
3025 map(i, Node_List::pop());
3026 --i; // Visit popped node
3027 // If it was last entry, loop terminates since size() was also reduced
3028 }
3029 }
3030 }
3031
3032 //=============================================================================
3033 void Node_Stack::grow() {
3034 size_t old_top = pointer_delta(_inode_top,_inodes,sizeof(INode)); // save _top
3035 size_t old_max = pointer_delta(_inode_max,_inodes,sizeof(INode));
3036 size_t max = old_max << 1; // max * 2
3037 _inodes = REALLOC_ARENA_ARRAY(_a, INode, _inodes, old_max, max);
3038 _inode_max = _inodes + max;
3039 _inode_top = _inodes + old_top; // restore _top
3040 }
3041
3042 // Node_Stack is used to map nodes.
3043 Node* Node_Stack::find(uint idx) const {
3044 uint sz = size();
3045 for (uint i = 0; i < sz; i++) {
3046 if (idx == index_at(i)) {
3047 return node_at(i);
3048 }
3049 }
3050 return nullptr;
3051 }
3052
3053 //=============================================================================
3054 uint TypeNode::size_of() const { return sizeof(*this); }
3055 #ifndef PRODUCT
3056 void TypeNode::dump_spec(outputStream *st) const {
3057 if (!Verbose && !WizardMode) {
3058 // standard dump does this in Verbose and WizardMode
3059 st->print(" #"); _type->dump_on(st);
3060 }
3061 }
3062
3063 void TypeNode::dump_compact_spec(outputStream *st) const {
3064 st->print("#");
3065 _type->dump_on(st);
3066 }
3067 #endif
3068 uint TypeNode::hash() const {
3069 return Node::hash() + _type->hash();
3070 }
3071 bool TypeNode::cmp(const Node& n) const {
3072 return Type::equals(_type, n.as_Type()->_type);
3073 }
3074 const Type* TypeNode::bottom_type() const { return _type; }
3075 const Type* TypeNode::Value(PhaseGVN* phase) const { return _type; }
3076
3077 //------------------------------ideal_reg--------------------------------------
3078 uint TypeNode::ideal_reg() const {
3079 return _type->ideal_reg();
3080 }
3081
3082 void TypeNode::make_path_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, Node* ctrl_use, uint j, const char* phase_str) {
3083 Node* c = ctrl_use->in(j);
3084 if (igvn->type(c) != Type::TOP) {
3085 igvn->replace_input_of(ctrl_use, j, igvn->C->top());
3086 create_halt_path(igvn, c, loop, phase_str);
3087 }
3088 }
3089
3090 // This Type node is dead. It could be because the type that it captures and the type of the node computed from its
3091 // inputs do not intersect anymore. That node has some uses along some control flow paths. Those control flow paths must
3092 // be unreachable as using a dead value makes no sense. For the Type node to capture a narrowed down type, some control
3093 // flow construct must guard the Type node (an If node usually). When the Type node becomes dead, the guard usually
3094 // constant folds and the control flow that leads to the Type node becomes unreachable. There are cases where that
3095 // doesn't happen, however. They are handled here by following uses of the Type node until a CFG or a Phi to find dead
3096 // paths. The dead paths are then replaced by a Halt node.
3097 void TypeNode::make_paths_from_here_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, const char* phase_str) {
3098 Unique_Node_List wq;
3099 wq.push(this);
3100 for (uint i = 0; i < wq.size(); ++i) {
3101 Node* n = wq.at(i);
3102 for (DUIterator_Fast kmax, k = n->fast_outs(kmax); k < kmax; k++) {
3103 Node* u = n->fast_out(k);
3104 if (u->is_CFG()) {
3105 assert(!u->is_Region(), "Can't reach a Region without going through a Phi");
3106 make_path_dead(igvn, loop, u, 0, phase_str);
3107 } else if (u->is_Phi()) {
3108 Node* r = u->in(0);
3109 assert(r->is_Region() || r->is_top(), "unexpected Phi's control");
3110 if (r->is_Region()) {
3111 for (uint j = 1; j < u->req(); ++j) {
3112 if (u->in(j) == n && r->in(j) != nullptr) {
3113 make_path_dead(igvn, loop, r, j, phase_str);
3114 }
3115 }
3116 }
3117 } else {
3118 wq.push(u);
3119 }
3120 }
3121 }
3122 }
3123
3124 void TypeNode::create_halt_path(PhaseIterGVN* igvn, Node* c, PhaseIdealLoop* loop, const char* phase_str) const {
3125 Node* frame = new ParmNode(igvn->C->start(), TypeFunc::FramePtr);
3126 if (loop == nullptr) {
3127 igvn->register_new_node_with_optimizer(frame);
3128 } else {
3129 loop->register_new_node(frame, igvn->C->start());
3130 }
3131
3132 stringStream ss;
3133 ss.print("dead path discovered by TypeNode during %s", phase_str);
3134
3135 Node* halt = new HaltNode(c, frame, ss.as_string(igvn->C->comp_arena()));
3136 if (loop == nullptr) {
3137 igvn->register_new_node_with_optimizer(halt);
3138 } else {
3139 loop->register_control(halt, loop->ltree_root(), c);
3140 }
3141 igvn->add_input_to(igvn->C->root(), halt);
3142 }
3143
3144 Node* TypeNode::Ideal(PhaseGVN* phase, bool can_reshape) {
3145 if (KillPathsReachableByDeadTypeNode && can_reshape && Value(phase) == Type::TOP) {
3146 PhaseIterGVN* igvn = phase->is_IterGVN();
3147 Node* top = igvn->C->top();
3148 ResourceMark rm;
3149 make_paths_from_here_dead(igvn, nullptr, "igvn");
3150 return top;
3151 }
3152
3153 return Node::Ideal(phase, can_reshape);
3154 }
3155