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