1 /*
2 * Copyright (c) 1998, 2024, 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 "asm/macroAssembler.inline.hpp"
27 #include "gc/shared/gc_globals.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "oops/compressedOops.hpp"
30 #include "opto/ad.hpp"
31 #include "opto/block.hpp"
32 #include "opto/c2compiler.hpp"
33 #include "opto/callnode.hpp"
34 #include "opto/cfgnode.hpp"
35 #include "opto/machnode.hpp"
36 #include "opto/runtime.hpp"
37 #include "opto/chaitin.hpp"
38 #include "runtime/os.inline.hpp"
39 #include "runtime/sharedRuntime.hpp"
40
41 // Optimization - Graph Style
42
43 // Check whether val is not-null-decoded compressed oop,
44 // i.e. will grab into the base of the heap if it represents null.
45 static bool accesses_heap_base_zone(Node *val) {
46 if (CompressedOops::base() != nullptr) { // Implies UseCompressedOops.
47 if (val && val->is_Mach()) {
48 if (val->as_Mach()->ideal_Opcode() == Op_DecodeN) {
49 // This assumes all Decodes with TypePtr::NotNull are matched to nodes that
50 // decode null to point to the heap base (Decode_NN).
51 if (val->bottom_type()->is_oopptr()->ptr() == TypePtr::NotNull) {
52 return true;
53 }
54 }
55 // Must recognize load operation with Decode matched in memory operand.
56 // We should not reach here except for PPC/AIX, as os::zero_page_read_protected()
57 // returns true everywhere else. On PPC, no such memory operands
58 // exist, therefore we did not yet implement a check for such operands.
59 NOT_AIX(Unimplemented());
60 }
61 }
62 return false;
63 }
64
65 static bool needs_explicit_null_check_for_read(Node *val) {
66 // On some OSes (AIX) the page at address 0 is only write protected.
67 // If so, only Store operations will trap.
68 if (os::zero_page_read_protected()) {
69 return false; // Implicit null check will work.
70 }
71 // Also a read accessing the base of a heap-based compressed heap will trap.
72 if (accesses_heap_base_zone(val) && // Hits the base zone page.
73 CompressedOops::use_implicit_null_checks()) { // Base zone page is protected.
74 return false;
75 }
76
77 return true;
78 }
79
80 //------------------------------implicit_null_check----------------------------
81 // Detect implicit-null-check opportunities. Basically, find null checks
82 // with suitable memory ops nearby. Use the memory op to do the null check.
83 // I can generate a memory op if there is not one nearby.
84 // The proj is the control projection for the not-null case.
85 // The val is the pointer being checked for nullness or
86 // decodeHeapOop_not_null node if it did not fold into address.
87 void PhaseCFG::implicit_null_check(Block* block, Node *proj, Node *val, int allowed_reasons) {
88 // Assume if null check need for 0 offset then always needed
89 // Intel solaris doesn't support any null checks yet and no
90 // mechanism exists (yet) to set the switches at an os_cpu level
91 if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return;
92
93 // Make sure the ptr-is-null path appears to be uncommon!
94 float f = block->end()->as_MachIf()->_prob;
95 if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f;
96 if( f > PROB_UNLIKELY_MAG(4) ) return;
97
98 uint bidx = 0; // Capture index of value into memop
99 bool was_store; // Memory op is a store op
100
101 // Get the successor block for if the test ptr is non-null
102 Block* not_null_block; // this one goes with the proj
103 Block* null_block;
104 if (block->get_node(block->number_of_nodes()-1) == proj) {
105 null_block = block->_succs[0];
106 not_null_block = block->_succs[1];
107 } else {
108 assert(block->get_node(block->number_of_nodes()-2) == proj, "proj is one or the other");
109 not_null_block = block->_succs[0];
110 null_block = block->_succs[1];
111 }
112 while (null_block->is_Empty() == Block::empty_with_goto) {
113 null_block = null_block->_succs[0];
114 }
115
116 // Search the exception block for an uncommon trap.
117 // (See Parse::do_if and Parse::do_ifnull for the reason
118 // we need an uncommon trap. Briefly, we need a way to
119 // detect failure of this optimization, as in 6366351.)
120 {
121 bool found_trap = false;
122 for (uint i1 = 0; i1 < null_block->number_of_nodes(); i1++) {
123 Node* nn = null_block->get_node(i1);
124 if (nn->is_MachCall() &&
125 nn->as_MachCall()->entry_point() == SharedRuntime::uncommon_trap_blob()->entry_point()) {
126 const Type* trtype = nn->in(TypeFunc::Parms)->bottom_type();
127 if (trtype->isa_int() && trtype->is_int()->is_con()) {
128 jint tr_con = trtype->is_int()->get_con();
129 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(tr_con);
130 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(tr_con);
131 assert((int)reason < (int)BitsPerInt, "recode bit map");
132 if (is_set_nth_bit(allowed_reasons, (int) reason)
133 && action != Deoptimization::Action_none) {
134 // This uncommon trap is sure to recompile, eventually.
135 // When that happens, C->too_many_traps will prevent
136 // this transformation from happening again.
137 found_trap = true;
138 }
139 }
140 break;
141 }
142 }
143 if (!found_trap) {
144 // We did not find an uncommon trap.
145 return;
146 }
147 }
148
149 // Check for decodeHeapOop_not_null node which did not fold into address
150 bool is_decoden = ((intptr_t)val) & 1;
151 val = (Node*)(((intptr_t)val) & ~1);
152
153 assert(!is_decoden ||
154 ((val->in(0) == nullptr) && val->is_Mach() &&
155 (val->as_Mach()->ideal_Opcode() == Op_DecodeN)), "sanity");
156
157 // Search the successor block for a load or store who's base value is also
158 // the tested value. There may be several.
159 MachNode *best = nullptr; // Best found so far
160 for (DUIterator i = val->outs(); val->has_out(i); i++) {
161 Node *m = val->out(i);
162 if( !m->is_Mach() ) continue;
163 MachNode *mach = m->as_Mach();
164 was_store = false;
165 int iop = mach->ideal_Opcode();
166 switch( iop ) {
167 case Op_LoadB:
168 case Op_LoadUB:
169 case Op_LoadUS:
170 case Op_LoadD:
171 case Op_LoadF:
172 case Op_LoadI:
173 case Op_LoadL:
174 case Op_LoadP:
175 case Op_LoadN:
176 case Op_LoadS:
177 case Op_LoadKlass:
178 case Op_LoadNKlass:
179 case Op_LoadRange:
180 case Op_LoadD_unaligned:
181 case Op_LoadL_unaligned:
182 assert(mach->in(2) == val, "should be address");
183 break;
184 case Op_StoreB:
185 case Op_StoreC:
186 case Op_StoreCM:
187 case Op_StoreD:
188 case Op_StoreF:
189 case Op_StoreI:
190 case Op_StoreL:
191 case Op_StoreP:
192 case Op_StoreN:
193 case Op_StoreNKlass:
194 was_store = true; // Memory op is a store op
195 // Stores will have their address in slot 2 (memory in slot 1).
196 // If the value being nul-checked is in another slot, it means we
197 // are storing the checked value, which does NOT check the value!
198 if( mach->in(2) != val ) continue;
199 break; // Found a memory op?
200 case Op_StrComp:
201 case Op_StrEquals:
202 case Op_StrIndexOf:
203 case Op_StrIndexOfChar:
204 case Op_AryEq:
205 case Op_VectorizedHashCode:
206 case Op_StrInflatedCopy:
207 case Op_StrCompressedCopy:
208 case Op_EncodeISOArray:
209 case Op_CountPositives:
210 // Not a legit memory op for implicit null check regardless of
211 // embedded loads
212 continue;
213 default: // Also check for embedded loads
214 if( !mach->needs_anti_dependence_check() )
215 continue; // Not an memory op; skip it
216 if( must_clone[iop] ) {
217 // Do not move nodes which produce flags because
218 // RA will try to clone it to place near branch and
219 // it will cause recompilation, see clone_node().
220 continue;
221 }
222 {
223 // Check that value is used in memory address in
224 // instructions with embedded load (CmpP val1,(val2+off)).
225 Node* base;
226 Node* index;
227 const MachOper* oper = mach->memory_inputs(base, index);
228 if (oper == nullptr || oper == (MachOper*)-1) {
229 continue; // Not an memory op; skip it
230 }
231 if (val == base ||
232 (val == index && val->bottom_type()->isa_narrowoop())) {
233 break; // Found it
234 } else {
235 continue; // Skip it
236 }
237 }
238 break;
239 }
240
241 // On some OSes (AIX) the page at address 0 is only write protected.
242 // If so, only Store operations will trap.
243 // But a read accessing the base of a heap-based compressed heap will trap.
244 if (!was_store && needs_explicit_null_check_for_read(val)) {
245 continue;
246 }
247
248 // Check that node's control edge is not-null block's head or dominates it,
249 // otherwise we can't hoist it because there are other control dependencies.
250 Node* ctrl = mach->in(0);
251 if (ctrl != nullptr && !(ctrl == not_null_block->head() ||
252 get_block_for_node(ctrl)->dominates(not_null_block))) {
253 continue;
254 }
255
256 // check if the offset is not too high for implicit exception
257 {
258 intptr_t offset = 0;
259 const TypePtr *adr_type = nullptr; // Do not need this return value here
260 const Node* base = mach->get_base_and_disp(offset, adr_type);
261 if (base == nullptr || base == NodeSentinel) {
262 // Narrow oop address doesn't have base, only index.
263 // Give up if offset is beyond page size or if heap base is not protected.
264 if (val->bottom_type()->isa_narrowoop() &&
265 (MacroAssembler::needs_explicit_null_check(offset) ||
266 !CompressedOops::use_implicit_null_checks()))
267 continue;
268 // cannot reason about it; is probably not implicit null exception
269 } else {
270 const TypePtr* tptr;
271 if ((UseCompressedOops || UseCompressedClassPointers) && 272 (CompressedOops::shift() == 0 || CompressedKlassPointers::shift() == 0)) {
273 // 32-bits narrow oop can be the base of address expressions
274 tptr = base->get_ptr_type();
275 } else {
276 // only regular oops are expected here
277 tptr = base->bottom_type()->is_ptr();
278 }
279 // Give up if offset is not a compile-time constant.
280 if (offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot)
281 continue;
282 offset += tptr->_offset; // correct if base is offsetted
283 // Give up if reference is beyond page size.
284 if (MacroAssembler::needs_explicit_null_check(offset))
285 continue;
286 // Give up if base is a decode node and the heap base is not protected.
287 if (base->is_Mach() && base->as_Mach()->ideal_Opcode() == Op_DecodeN &&
288 !CompressedOops::use_implicit_null_checks())
289 continue;
290 }
291 }
292
293 // Check ctrl input to see if the null-check dominates the memory op
294 Block *cb = get_block_for_node(mach);
295 cb = cb->_idom; // Always hoist at least 1 block
296 if( !was_store ) { // Stores can be hoisted only one block
297 while( cb->_dom_depth > (block->_dom_depth + 1))
298 cb = cb->_idom; // Hoist loads as far as we want
299 // The non-null-block should dominate the memory op, too. Live
300 // range spilling will insert a spill in the non-null-block if it is
301 // needs to spill the memory op for an implicit null check.
302 if (cb->_dom_depth == (block->_dom_depth + 1)) {
303 if (cb != not_null_block) continue;
304 cb = cb->_idom;
305 }
306 }
307 if( cb != block ) continue;
308
309 // Found a memory user; see if it can be hoisted to check-block
310 uint vidx = 0; // Capture index of value into memop
311 uint j;
312 for( j = mach->req()-1; j > 0; j-- ) {
313 if( mach->in(j) == val ) {
314 vidx = j;
315 // Ignore DecodeN val which could be hoisted to where needed.
316 if( is_decoden ) continue;
317 }
318 // Block of memory-op input
319 Block *inb = get_block_for_node(mach->in(j));
320 Block *b = block; // Start from nul check
321 while( b != inb && b->_dom_depth > inb->_dom_depth )
322 b = b->_idom; // search upwards for input
323 // See if input dominates null check
324 if( b != inb )
325 break;
326 }
327 if( j > 0 )
328 continue;
329 Block *mb = get_block_for_node(mach);
330 // Hoisting stores requires more checks for the anti-dependence case.
331 // Give up hoisting if we have to move the store past any load.
332 if (was_store) {
333 // Make sure control does not do a merge (would have to check allpaths)
334 if (mb->num_preds() != 2) {
335 continue;
336 }
337 // mach is a store, hence block is the immediate dominator of mb.
338 // Due to the null-check shape of block (where its successors cannot re-join),
339 // block must be the direct predecessor of mb.
340 assert(get_block_for_node(mb->pred(1)) == block, "Unexpected predecessor block");
341 uint k;
342 uint num_nodes = mb->number_of_nodes();
343 for (k = 1; k < num_nodes; k++) {
344 Node *n = mb->get_node(k);
345 if (n->needs_anti_dependence_check() &&
346 n->in(LoadNode::Memory) == mach->in(StoreNode::Memory)) {
347 break; // Found anti-dependent load
348 }
349 }
350 if (k < num_nodes) {
351 continue; // Found anti-dependent load
352 }
353 }
354
355 // Make sure this memory op is not already being used for a NullCheck
356 Node *e = mb->end();
357 if( e->is_MachNullCheck() && e->in(1) == mach )
358 continue; // Already being used as a null check
359
360 // Found a candidate! Pick one with least dom depth - the highest
361 // in the dom tree should be closest to the null check.
362 if (best == nullptr || get_block_for_node(mach)->_dom_depth < get_block_for_node(best)->_dom_depth) {
363 best = mach;
364 bidx = vidx;
365 }
366 }
367 // No candidate!
368 if (best == nullptr) {
369 return;
370 }
371
372 // ---- Found an implicit null check
373 #ifndef PRODUCT
374 extern uint implicit_null_checks;
375 implicit_null_checks++;
376 #endif
377
378 if( is_decoden ) {
379 // Check if we need to hoist decodeHeapOop_not_null first.
380 Block *valb = get_block_for_node(val);
381 if( block != valb && block->_dom_depth < valb->_dom_depth ) {
382 // Hoist it up to the end of the test block together with its inputs if they exist.
383 for (uint i = 2; i < val->req(); i++) {
384 // DecodeN has 2 regular inputs + optional MachTemp or load Base inputs.
385 Node *temp = val->in(i);
386 Block *tempb = get_block_for_node(temp);
387 if (!tempb->dominates(block)) {
388 assert(block->dominates(tempb), "sanity check: temp node placement");
389 // We only expect nodes without further inputs, like MachTemp or load Base.
390 assert(temp->req() == 0 || (temp->req() == 1 && temp->in(0) == (Node*)C->root()),
391 "need for recursive hoisting not expected");
392 tempb->find_remove(temp);
393 block->add_inst(temp);
394 map_node_to_block(temp, block);
395 }
396 }
397 valb->find_remove(val);
398 block->add_inst(val);
399 map_node_to_block(val, block);
400 // DecodeN on x86 may kill flags. Check for flag-killing projections
401 // that also need to be hoisted.
402 for (DUIterator_Fast jmax, j = val->fast_outs(jmax); j < jmax; j++) {
403 Node* n = val->fast_out(j);
404 if( n->is_MachProj() ) {
405 get_block_for_node(n)->find_remove(n);
406 block->add_inst(n);
407 map_node_to_block(n, block);
408 }
409 }
410 }
411 }
412 // Hoist the memory candidate up to the end of the test block.
413 Block *old_block = get_block_for_node(best);
414 old_block->find_remove(best);
415 block->add_inst(best);
416 map_node_to_block(best, block);
417
418 // Move the control dependence if it is pinned to not-null block.
419 // Don't change it in other cases: null or dominating control.
420 Node* ctrl = best->in(0);
421 if (ctrl != nullptr && get_block_for_node(ctrl) == not_null_block) {
422 // Set it to control edge of null check.
423 best->set_req(0, proj->in(0)->in(0));
424 }
425
426 // Check for flag-killing projections that also need to be hoisted
427 // Should be DU safe because no edge updates.
428 for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) {
429 Node* n = best->fast_out(j);
430 if( n->is_MachProj() ) {
431 get_block_for_node(n)->find_remove(n);
432 block->add_inst(n);
433 map_node_to_block(n, block);
434 }
435 }
436
437 // proj==Op_True --> ne test; proj==Op_False --> eq test.
438 // One of two graph shapes got matched:
439 // (IfTrue (If (Bool NE (CmpP ptr null))))
440 // (IfFalse (If (Bool EQ (CmpP ptr null))))
441 // null checks are always branch-if-eq. If we see a IfTrue projection
442 // then we are replacing a 'ne' test with a 'eq' null check test.
443 // We need to flip the projections to keep the same semantics.
444 if( proj->Opcode() == Op_IfTrue ) {
445 // Swap order of projections in basic block to swap branch targets
446 Node *tmp1 = block->get_node(block->end_idx()+1);
447 Node *tmp2 = block->get_node(block->end_idx()+2);
448 block->map_node(tmp2, block->end_idx()+1);
449 block->map_node(tmp1, block->end_idx()+2);
450 Node *tmp = new Node(C->top()); // Use not null input
451 tmp1->replace_by(tmp);
452 tmp2->replace_by(tmp1);
453 tmp->replace_by(tmp2);
454 tmp->destruct(nullptr);
455 }
456
457 // Remove the existing null check; use a new implicit null check instead.
458 // Since schedule-local needs precise def-use info, we need to correct
459 // it as well.
460 Node *old_tst = proj->in(0);
461 MachNode *nul_chk = new MachNullCheckNode(old_tst->in(0),best,bidx);
462 block->map_node(nul_chk, block->end_idx());
463 map_node_to_block(nul_chk, block);
464 // Redirect users of old_test to nul_chk
465 for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2)
466 old_tst->last_out(i2)->set_req(0, nul_chk);
467 // Clean-up any dead code
468 for (uint i3 = 0; i3 < old_tst->req(); i3++) {
469 Node* in = old_tst->in(i3);
470 old_tst->set_req(i3, nullptr);
471 if (in->outcnt() == 0) {
472 // Remove dead input node
473 in->disconnect_inputs(C);
474 block->find_remove(in);
475 }
476 }
477
478 latency_from_uses(nul_chk);
479 latency_from_uses(best);
480
481 // insert anti-dependences to defs in this block
482 if (! best->needs_anti_dependence_check()) {
483 for (uint k = 1; k < block->number_of_nodes(); k++) {
484 Node *n = block->get_node(k);
485 if (n->needs_anti_dependence_check() &&
486 n->in(LoadNode::Memory) == best->in(StoreNode::Memory)) {
487 // Found anti-dependent load
488 insert_anti_dependences(block, n);
489 }
490 }
491 }
492 }
493
494
495 //------------------------------select-----------------------------------------
496 // Select a nice fellow from the worklist to schedule next. If there is only one
497 // choice, then use it. CreateEx nodes that are initially ready must start their
498 // blocks and are given the highest priority, by being placed at the beginning
499 // of the worklist. Next after initially-ready CreateEx nodes are projections,
500 // which must follow their parents, and CreateEx nodes with local input
501 // dependencies. Next are constants and CheckCastPP nodes. There are a number of
502 // other special cases, for instructions that consume condition codes, et al.
503 // These are chosen immediately. Some instructions are required to immediately
504 // precede the last instruction in the block, and these are taken last. Of the
505 // remaining cases (most), choose the instruction with the greatest latency
506 // (that is, the most number of pseudo-cycles required to the end of the
507 // routine). If there is a tie, choose the instruction with the most inputs.
508 Node* PhaseCFG::select(
509 Block* block,
510 Node_List &worklist,
511 GrowableArray<int> &ready_cnt,
512 VectorSet &next_call,
513 uint sched_slot,
514 intptr_t* recalc_pressure_nodes) {
515
516 // If only a single entry on the stack, use it
517 uint cnt = worklist.size();
518 if (cnt == 1) {
519 Node *n = worklist[0];
520 worklist.map(0,worklist.pop());
521 return n;
522 }
523
524 uint choice = 0; // Bigger is most important
525 uint latency = 0; // Bigger is scheduled first
526 uint score = 0; // Bigger is better
527 int idx = -1; // Index in worklist
528 int cand_cnt = 0; // Candidate count
529 bool block_size_threshold_ok = (recalc_pressure_nodes != nullptr) && (block->number_of_nodes() > 10);
530
531 for( uint i=0; i<cnt; i++ ) { // Inspect entire worklist
532 // Order in worklist is used to break ties.
533 // See caller for how this is used to delay scheduling
534 // of induction variable increments to after the other
535 // uses of the phi are scheduled.
536 Node *n = worklist[i]; // Get Node on worklist
537
538 int iop = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : 0;
539 if (iop == Op_CreateEx || n->is_Proj()) {
540 // CreateEx nodes that are initially ready must start the block (after Phi
541 // and Parm nodes which are pre-scheduled) and get top priority. This is
542 // currently enforced by placing them at the beginning of the initial
543 // worklist and selecting them eagerly here. After these, projections and
544 // other CreateEx nodes are selected with equal priority.
545 worklist.map(i,worklist.pop());
546 return n;
547 }
548
549 if (n->Opcode() == Op_Con || iop == Op_CheckCastPP) {
550 // Constants and CheckCastPP nodes have higher priority than the rest of
551 // the nodes tested below. Record as current winner, but keep looking for
552 // higher-priority nodes in the worklist.
553 choice = 4;
554 // Latency and score are only used to break ties among low-priority nodes.
555 latency = 0;
556 score = 0;
557 idx = i;
558 continue;
559 }
560
561 // Final call in a block must be adjacent to 'catch'
562 Node *e = block->end();
563 if( e->is_Catch() && e->in(0)->in(0) == n )
564 continue;
565
566 // Memory op for an implicit null check has to be at the end of the block
567 if( e->is_MachNullCheck() && e->in(1) == n )
568 continue;
569
570 // Schedule IV increment last.
571 if (e->is_Mach() && e->as_Mach()->ideal_Opcode() == Op_CountedLoopEnd) {
572 // Cmp might be matched into CountedLoopEnd node.
573 Node *cmp = (e->in(1)->ideal_reg() == Op_RegFlags) ? e->in(1) : e;
574 if (cmp->req() > 1 && cmp->in(1) == n && n->is_iteratively_computed()) {
575 continue;
576 }
577 }
578
579 uint n_choice = 2;
580
581 // See if this instruction is consumed by a branch. If so, then (as the
582 // branch is the last instruction in the basic block) force it to the
583 // end of the basic block
584 if ( must_clone[iop] ) {
585 // See if any use is a branch
586 bool found_machif = false;
587
588 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
589 Node* use = n->fast_out(j);
590
591 // The use is a conditional branch, make them adjacent
592 if (use->is_MachIf() && get_block_for_node(use) == block) {
593 found_machif = true;
594 break;
595 }
596
597 // More than this instruction pending for successor to be ready,
598 // don't choose this if other opportunities are ready
599 if (ready_cnt.at(use->_idx) > 1)
600 n_choice = 1;
601 }
602
603 // loop terminated, prefer not to use this instruction
604 if (found_machif)
605 continue;
606 }
607
608 // See if this has a predecessor that is "must_clone", i.e. sets the
609 // condition code. If so, choose this first
610 for (uint j = 0; j < n->req() ; j++) {
611 Node *inn = n->in(j);
612 if (inn) {
613 if (inn->is_Mach() && must_clone[inn->as_Mach()->ideal_Opcode()] ) {
614 n_choice = 3;
615 break;
616 }
617 }
618 }
619
620 // MachTemps should be scheduled last so they are near their uses
621 if (n->is_MachTemp()) {
622 n_choice = 1;
623 }
624
625 uint n_latency = get_latency_for_node(n);
626 uint n_score = n->req(); // Many inputs get high score to break ties
627
628 if (OptoRegScheduling && block_size_threshold_ok) {
629 if (recalc_pressure_nodes[n->_idx] == 0x7fff7fff) {
630 _regalloc->_scratch_int_pressure.init(_regalloc->_sched_int_pressure.high_pressure_limit());
631 _regalloc->_scratch_float_pressure.init(_regalloc->_sched_float_pressure.high_pressure_limit());
632 // simulate the notion that we just picked this node to schedule
633 n->add_flag(Node::Flag_is_scheduled);
634 // now calculate its effect upon the graph if we did
635 adjust_register_pressure(n, block, recalc_pressure_nodes, false);
636 // return its state for finalize in case somebody else wins
637 n->remove_flag(Node::Flag_is_scheduled);
638 // now save the two final pressure components of register pressure, limiting pressure calcs to short size
639 short int_pressure = (short)_regalloc->_scratch_int_pressure.current_pressure();
640 short float_pressure = (short)_regalloc->_scratch_float_pressure.current_pressure();
641 recalc_pressure_nodes[n->_idx] = int_pressure;
642 recalc_pressure_nodes[n->_idx] |= (float_pressure << 16);
643 }
644
645 if (_scheduling_for_pressure) {
646 latency = n_latency;
647 if (n_choice != 3) {
648 // Now evaluate each register pressure component based on threshold in the score.
649 // In general the defining register type will dominate the score, ergo we will not see register pressure grow on both banks
650 // on a single instruction, but we might see it shrink on both banks.
651 // For each use of register that has a register class that is over the high pressure limit, we build n_score up for
652 // live ranges that terminate on this instruction.
653 if (_regalloc->_sched_int_pressure.current_pressure() > _regalloc->_sched_int_pressure.high_pressure_limit()) {
654 short int_pressure = (short)recalc_pressure_nodes[n->_idx];
655 n_score = (int_pressure < 0) ? ((score + n_score) - int_pressure) : (int_pressure > 0) ? 1 : n_score;
656 }
657 if (_regalloc->_sched_float_pressure.current_pressure() > _regalloc->_sched_float_pressure.high_pressure_limit()) {
658 short float_pressure = (short)(recalc_pressure_nodes[n->_idx] >> 16);
659 n_score = (float_pressure < 0) ? ((score + n_score) - float_pressure) : (float_pressure > 0) ? 1 : n_score;
660 }
661 } else {
662 // make sure we choose these candidates
663 score = 0;
664 }
665 }
666 }
667
668 // Keep best latency found
669 cand_cnt++;
670 if (choice < n_choice ||
671 (choice == n_choice &&
672 ((StressLCM && C->randomized_select(cand_cnt)) ||
673 (!StressLCM &&
674 (latency < n_latency ||
675 (latency == n_latency &&
676 (score < n_score))))))) {
677 choice = n_choice;
678 latency = n_latency;
679 score = n_score;
680 idx = i; // Also keep index in worklist
681 }
682 } // End of for all ready nodes in worklist
683
684 guarantee(idx >= 0, "index should be set");
685 Node *n = worklist[(uint)idx]; // Get the winner
686
687 worklist.map((uint)idx, worklist.pop()); // Compress worklist
688 return n;
689 }
690
691 //-------------------------adjust_register_pressure----------------------------
692 void PhaseCFG::adjust_register_pressure(Node* n, Block* block, intptr_t* recalc_pressure_nodes, bool finalize_mode) {
693 PhaseLive* liveinfo = _regalloc->get_live();
694 IndexSet* liveout = liveinfo->live(block);
695 // first adjust the register pressure for the sources
696 for (uint i = 1; i < n->req(); i++) {
697 bool lrg_ends = false;
698 Node *src_n = n->in(i);
699 if (src_n == nullptr) continue;
700 if (!src_n->is_Mach()) continue;
701 uint src = _regalloc->_lrg_map.find(src_n);
702 if (src == 0) continue;
703 LRG& lrg_src = _regalloc->lrgs(src);
704 // detect if the live range ends or not
705 if (liveout->member(src) == false) {
706 lrg_ends = true;
707 for (DUIterator_Fast jmax, j = src_n->fast_outs(jmax); j < jmax; j++) {
708 Node* m = src_n->fast_out(j); // Get user
709 if (m == n) continue;
710 if (!m->is_Mach()) continue;
711 MachNode *mach = m->as_Mach();
712 bool src_matches = false;
713 int iop = mach->ideal_Opcode();
714
715 switch (iop) {
716 case Op_StoreB:
717 case Op_StoreC:
718 case Op_StoreCM:
719 case Op_StoreD:
720 case Op_StoreF:
721 case Op_StoreI:
722 case Op_StoreL:
723 case Op_StoreP:
724 case Op_StoreN:
725 case Op_StoreVector:
726 case Op_StoreVectorMasked:
727 case Op_StoreVectorScatter:
728 case Op_StoreVectorScatterMasked:
729 case Op_StoreNKlass:
730 for (uint k = 1; k < m->req(); k++) {
731 Node *in = m->in(k);
732 if (in == src_n) {
733 src_matches = true;
734 break;
735 }
736 }
737 break;
738
739 default:
740 src_matches = true;
741 break;
742 }
743
744 // If we have a store as our use, ignore the non source operands
745 if (src_matches == false) continue;
746
747 // Mark every unscheduled use which is not n with a recalculation
748 if ((get_block_for_node(m) == block) && (!m->is_scheduled())) {
749 if (finalize_mode && !m->is_Phi()) {
750 recalc_pressure_nodes[m->_idx] = 0x7fff7fff;
751 }
752 lrg_ends = false;
753 }
754 }
755 }
756 // if none, this live range ends and we can adjust register pressure
757 if (lrg_ends) {
758 if (finalize_mode) {
759 _regalloc->lower_pressure(block, 0, lrg_src, nullptr, _regalloc->_sched_int_pressure, _regalloc->_sched_float_pressure);
760 } else {
761 _regalloc->lower_pressure(block, 0, lrg_src, nullptr, _regalloc->_scratch_int_pressure, _regalloc->_scratch_float_pressure);
762 }
763 }
764 }
765
766 // now add the register pressure from the dest and evaluate which heuristic we should use:
767 // 1.) The default, latency scheduling
768 // 2.) Register pressure scheduling based on the high pressure limit threshold for int or float register stacks
769 uint dst = _regalloc->_lrg_map.find(n);
770 if (dst != 0) {
771 LRG& lrg_dst = _regalloc->lrgs(dst);
772 if (finalize_mode) {
773 _regalloc->raise_pressure(block, lrg_dst, _regalloc->_sched_int_pressure, _regalloc->_sched_float_pressure);
774 // check to see if we fall over the register pressure cliff here
775 if (_regalloc->_sched_int_pressure.current_pressure() > _regalloc->_sched_int_pressure.high_pressure_limit()) {
776 _scheduling_for_pressure = true;
777 } else if (_regalloc->_sched_float_pressure.current_pressure() > _regalloc->_sched_float_pressure.high_pressure_limit()) {
778 _scheduling_for_pressure = true;
779 } else {
780 // restore latency scheduling mode
781 _scheduling_for_pressure = false;
782 }
783 } else {
784 _regalloc->raise_pressure(block, lrg_dst, _regalloc->_scratch_int_pressure, _regalloc->_scratch_float_pressure);
785 }
786 }
787 }
788
789 //------------------------------set_next_call----------------------------------
790 void PhaseCFG::set_next_call(Block* block, Node* n, VectorSet& next_call) {
791 if( next_call.test_set(n->_idx) ) return;
792 for( uint i=0; i<n->len(); i++ ) {
793 Node *m = n->in(i);
794 if( !m ) continue; // must see all nodes in block that precede call
795 if (get_block_for_node(m) == block) {
796 set_next_call(block, m, next_call);
797 }
798 }
799 }
800
801 //------------------------------needed_for_next_call---------------------------
802 // Set the flag 'next_call' for each Node that is needed for the next call to
803 // be scheduled. This flag lets me bias scheduling so Nodes needed for the
804 // next subroutine call get priority - basically it moves things NOT needed
805 // for the next call till after the call. This prevents me from trying to
806 // carry lots of stuff live across a call.
807 void PhaseCFG::needed_for_next_call(Block* block, Node* this_call, VectorSet& next_call) {
808 // Find the next control-defining Node in this block
809 Node* call = nullptr;
810 for (DUIterator_Fast imax, i = this_call->fast_outs(imax); i < imax; i++) {
811 Node* m = this_call->fast_out(i);
812 if (get_block_for_node(m) == block && // Local-block user
813 m != this_call && // Not self-start node
814 m->is_MachCall()) {
815 call = m;
816 break;
817 }
818 }
819 if (call == nullptr) return; // No next call (e.g., block end is near)
820 // Set next-call for all inputs to this call
821 set_next_call(block, call, next_call);
822 }
823
824 //------------------------------add_call_kills-------------------------------------
825 // helper function that adds caller save registers to MachProjNode
826 static void add_call_kills(MachProjNode *proj, RegMask& regs, const char* save_policy, bool exclude_soe) {
827 // Fill in the kill mask for the call
828 for( OptoReg::Name r = OptoReg::Name(0); r < _last_Mach_Reg; r=OptoReg::add(r,1) ) {
829 if( !regs.Member(r) ) { // Not already defined by the call
830 // Save-on-call register?
831 if ((save_policy[r] == 'C') ||
832 (save_policy[r] == 'A') ||
833 ((save_policy[r] == 'E') && exclude_soe)) {
834 proj->_rout.Insert(r);
835 }
836 }
837 }
838 }
839
840
841 //------------------------------sched_call-------------------------------------
842 uint PhaseCFG::sched_call(Block* block, uint node_cnt, Node_List& worklist, GrowableArray<int>& ready_cnt, MachCallNode* mcall, VectorSet& next_call) {
843 RegMask regs;
844
845 // Schedule all the users of the call right now. All the users are
846 // projection Nodes, so they must be scheduled next to the call.
847 // Collect all the defined registers.
848 for (DUIterator_Fast imax, i = mcall->fast_outs(imax); i < imax; i++) {
849 Node* n = mcall->fast_out(i);
850 assert( n->is_MachProj(), "" );
851 int n_cnt = ready_cnt.at(n->_idx)-1;
852 ready_cnt.at_put(n->_idx, n_cnt);
853 assert( n_cnt == 0, "" );
854 // Schedule next to call
855 block->map_node(n, node_cnt++);
856 // Collect defined registers
857 regs.OR(n->out_RegMask());
858 // Check for scheduling the next control-definer
859 if( n->bottom_type() == Type::CONTROL )
860 // Warm up next pile of heuristic bits
861 needed_for_next_call(block, n, next_call);
862
863 // Children of projections are now all ready
864 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
865 Node* m = n->fast_out(j); // Get user
866 if(get_block_for_node(m) != block) {
867 continue;
868 }
869 if( m->is_Phi() ) continue;
870 int m_cnt = ready_cnt.at(m->_idx) - 1;
871 ready_cnt.at_put(m->_idx, m_cnt);
872 if( m_cnt == 0 )
873 worklist.push(m);
874 }
875
876 }
877
878 // Act as if the call defines the Frame Pointer.
879 // Certainly the FP is alive and well after the call.
880 regs.Insert(_matcher.c_frame_pointer());
881
882 // Set all registers killed and not already defined by the call.
883 uint r_cnt = mcall->tf()->range()->cnt();
884 int op = mcall->ideal_Opcode();
885 MachProjNode *proj = new MachProjNode( mcall, r_cnt+1, RegMask::Empty, MachProjNode::fat_proj );
886 map_node_to_block(proj, block);
887 block->insert_node(proj, node_cnt++);
888
889 // Select the right register save policy.
890 const char *save_policy = nullptr;
891 switch (op) {
892 case Op_CallRuntime:
893 case Op_CallLeaf:
894 case Op_CallLeafNoFP:
895 case Op_CallLeafVector:
896 // Calling C code so use C calling convention
897 save_policy = _matcher._c_reg_save_policy;
898 break;
899
900 case Op_CallStaticJava:
901 case Op_CallDynamicJava:
902 // Calling Java code so use Java calling convention
903 save_policy = _matcher._register_save_policy;
904 break;
905
906 default:
907 ShouldNotReachHere();
908 }
909
910 // When using CallRuntime mark SOE registers as killed by the call
911 // so values that could show up in the RegisterMap aren't live in a
912 // callee saved register since the register wouldn't know where to
913 // find them. CallLeaf and CallLeafNoFP are ok because they can't
914 // have debug info on them. Strictly speaking this only needs to be
915 // done for oops since idealreg2debugmask takes care of debug info
916 // references but there no way to handle oops differently than other
917 // pointers as far as the kill mask goes.
918 bool exclude_soe = op == Op_CallRuntime;
919
920 // If the call is a MethodHandle invoke, we need to exclude the
921 // register which is used to save the SP value over MH invokes from
922 // the mask. Otherwise this register could be used for
923 // deoptimization information.
924 if (op == Op_CallStaticJava) {
925 MachCallStaticJavaNode* mcallstaticjava = (MachCallStaticJavaNode*) mcall;
926 if (mcallstaticjava->_method_handle_invoke)
927 proj->_rout.OR(Matcher::method_handle_invoke_SP_save_mask());
928 }
929
930 add_call_kills(proj, regs, save_policy, exclude_soe);
931
932 return node_cnt;
933 }
934
935
936 //------------------------------schedule_local---------------------------------
937 // Topological sort within a block. Someday become a real scheduler.
938 bool PhaseCFG::schedule_local(Block* block, GrowableArray<int>& ready_cnt, VectorSet& next_call, intptr_t *recalc_pressure_nodes) {
939 // Already "sorted" are the block start Node (as the first entry), and
940 // the block-ending Node and any trailing control projections. We leave
941 // these alone. PhiNodes and ParmNodes are made to follow the block start
942 // Node. Everything else gets topo-sorted.
943
944 #ifndef PRODUCT
945 if (trace_opto_pipelining()) {
946 tty->print_cr("# --- schedule_local B%d, before: ---", block->_pre_order);
947 for (uint i = 0;i < block->number_of_nodes(); i++) {
948 tty->print("# ");
949 block->get_node(i)->dump();
950 }
951 tty->print_cr("#");
952 }
953 #endif
954
955 // RootNode is already sorted
956 if (block->number_of_nodes() == 1) {
957 return true;
958 }
959
960 bool block_size_threshold_ok = (recalc_pressure_nodes != nullptr) && (block->number_of_nodes() > 10);
961
962 // We track the uses of local definitions as input dependences so that
963 // we know when a given instruction is available to be scheduled.
964 uint i;
965 if (OptoRegScheduling && block_size_threshold_ok) {
966 for (i = 1; i < block->number_of_nodes(); i++) { // setup nodes for pressure calc
967 Node *n = block->get_node(i);
968 n->remove_flag(Node::Flag_is_scheduled);
969 if (!n->is_Phi()) {
970 recalc_pressure_nodes[n->_idx] = 0x7fff7fff;
971 }
972 }
973 }
974
975 // Move PhiNodes and ParmNodes from 1 to cnt up to the start
976 uint node_cnt = block->end_idx();
977 uint phi_cnt = 1;
978 for( i = 1; i<node_cnt; i++ ) { // Scan for Phi
979 Node *n = block->get_node(i);
980 if( n->is_Phi() || // Found a PhiNode or ParmNode
981 (n->is_Proj() && n->in(0) == block->head()) ) {
982 // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt
983 block->map_node(block->get_node(phi_cnt), i);
984 block->map_node(n, phi_cnt++); // swap Phi/Parm up front
985 if (OptoRegScheduling && block_size_threshold_ok) {
986 // mark n as scheduled
987 n->add_flag(Node::Flag_is_scheduled);
988 }
989 } else { // All others
990 // Count block-local inputs to 'n'
991 uint cnt = n->len(); // Input count
992 uint local = 0;
993 for( uint j=0; j<cnt; j++ ) {
994 Node *m = n->in(j);
995 if( m && get_block_for_node(m) == block && !m->is_top() )
996 local++; // One more block-local input
997 }
998 ready_cnt.at_put(n->_idx, local); // Count em up
999
1000 #ifdef ASSERT
1001 if (UseG1GC) {
1002 if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_StoreCM ) {
1003 // Check the precedence edges
1004 for (uint prec = n->req(); prec < n->len(); prec++) {
1005 Node* oop_store = n->in(prec);
1006 if (oop_store != nullptr) {
1007 assert(get_block_for_node(oop_store)->_dom_depth <= block->_dom_depth, "oop_store must dominate card-mark");
1008 }
1009 }
1010 }
1011 }
1012 #endif
1013
1014 // A few node types require changing a required edge to a precedence edge
1015 // before allocation.
1016 if( n->is_Mach() && n->req() > TypeFunc::Parms &&
1017 (n->as_Mach()->ideal_Opcode() == Op_MemBarAcquire ||
1018 n->as_Mach()->ideal_Opcode() == Op_MemBarVolatile) ) {
1019 // MemBarAcquire could be created without Precedent edge.
1020 // del_req() replaces the specified edge with the last input edge
1021 // and then removes the last edge. If the specified edge > number of
1022 // edges the last edge will be moved outside of the input edges array
1023 // and the edge will be lost. This is why this code should be
1024 // executed only when Precedent (== TypeFunc::Parms) edge is present.
1025 Node *x = n->in(TypeFunc::Parms);
1026 if (x != nullptr && get_block_for_node(x) == block && n->find_prec_edge(x) != -1) {
1027 // Old edge to node within same block will get removed, but no precedence
1028 // edge will get added because it already exists. Update ready count.
1029 int cnt = ready_cnt.at(n->_idx);
1030 assert(cnt > 1, "MemBar node %d must not get ready here", n->_idx);
1031 ready_cnt.at_put(n->_idx, cnt-1);
1032 }
1033 n->del_req(TypeFunc::Parms);
1034 n->add_prec(x);
1035 }
1036 }
1037 }
1038 for(uint i2=i; i2< block->number_of_nodes(); i2++ ) // Trailing guys get zapped count
1039 ready_cnt.at_put(block->get_node(i2)->_idx, 0);
1040
1041 // All the prescheduled guys do not hold back internal nodes
1042 uint i3;
1043 for (i3 = 0; i3 < phi_cnt; i3++) { // For all pre-scheduled
1044 Node *n = block->get_node(i3); // Get pre-scheduled
1045 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
1046 Node* m = n->fast_out(j);
1047 if (get_block_for_node(m) == block) { // Local-block user
1048 int m_cnt = ready_cnt.at(m->_idx)-1;
1049 if (OptoRegScheduling && block_size_threshold_ok) {
1050 // mark m as scheduled
1051 if (m_cnt < 0) {
1052 m->add_flag(Node::Flag_is_scheduled);
1053 }
1054 }
1055 ready_cnt.at_put(m->_idx, m_cnt); // Fix ready count
1056 }
1057 }
1058 }
1059
1060 Node_List delay;
1061 // Make a worklist
1062 Node_List worklist;
1063 for(uint i4=i3; i4<node_cnt; i4++ ) { // Put ready guys on worklist
1064 Node *m = block->get_node(i4);
1065 if( !ready_cnt.at(m->_idx) ) { // Zero ready count?
1066 if (m->is_iteratively_computed()) {
1067 // Push induction variable increments last to allow other uses
1068 // of the phi to be scheduled first. The select() method breaks
1069 // ties in scheduling by worklist order.
1070 delay.push(m);
1071 } else if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CreateEx) {
1072 // Place CreateEx nodes that are initially ready at the beginning of the
1073 // worklist so they are selected first and scheduled at the block start.
1074 worklist.insert(0, m);
1075 } else {
1076 worklist.push(m); // Then on to worklist!
1077 }
1078 }
1079 }
1080 while (delay.size()) {
1081 Node* d = delay.pop();
1082 worklist.push(d);
1083 }
1084
1085 if (OptoRegScheduling && block_size_threshold_ok) {
1086 // To stage register pressure calculations we need to examine the live set variables
1087 // breaking them up by register class to compartmentalize the calculations.
1088 _regalloc->_sched_int_pressure.init(Matcher::int_pressure_limit());
1089 _regalloc->_sched_float_pressure.init(Matcher::float_pressure_limit());
1090 _regalloc->_scratch_int_pressure.init(Matcher::int_pressure_limit());
1091 _regalloc->_scratch_float_pressure.init(Matcher::float_pressure_limit());
1092
1093 _regalloc->compute_entry_block_pressure(block);
1094 }
1095
1096 // Warm up the 'next_call' heuristic bits
1097 needed_for_next_call(block, block->head(), next_call);
1098
1099 #ifndef PRODUCT
1100 if (trace_opto_pipelining()) {
1101 for (uint j=0; j< block->number_of_nodes(); j++) {
1102 Node *n = block->get_node(j);
1103 int idx = n->_idx;
1104 tty->print("# ready cnt:%3d ", ready_cnt.at(idx));
1105 tty->print("latency:%3d ", get_latency_for_node(n));
1106 tty->print("%4d: %s\n", idx, n->Name());
1107 }
1108 }
1109 #endif
1110
1111 uint max_idx = (uint)ready_cnt.length();
1112 // Pull from worklist and schedule
1113 while( worklist.size() ) { // Worklist is not ready
1114
1115 #ifndef PRODUCT
1116 if (trace_opto_pipelining()) {
1117 tty->print("# ready list:");
1118 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
1119 Node *n = worklist[i]; // Get Node on worklist
1120 tty->print(" %d", n->_idx);
1121 }
1122 tty->cr();
1123 }
1124 #endif
1125
1126 // Select and pop a ready guy from worklist
1127 Node* n = select(block, worklist, ready_cnt, next_call, phi_cnt, recalc_pressure_nodes);
1128 block->map_node(n, phi_cnt++); // Schedule him next
1129
1130 if (OptoRegScheduling && block_size_threshold_ok) {
1131 n->add_flag(Node::Flag_is_scheduled);
1132
1133 // Now adjust the resister pressure with the node we selected
1134 if (!n->is_Phi()) {
1135 adjust_register_pressure(n, block, recalc_pressure_nodes, true);
1136 }
1137 }
1138
1139 #ifndef PRODUCT
1140 if (trace_opto_pipelining()) {
1141 tty->print("# select %d: %s", n->_idx, n->Name());
1142 tty->print(", latency:%d", get_latency_for_node(n));
1143 n->dump();
1144 if (Verbose) {
1145 tty->print("# ready list:");
1146 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
1147 Node *n = worklist[i]; // Get Node on worklist
1148 tty->print(" %d", n->_idx);
1149 }
1150 tty->cr();
1151 }
1152 }
1153
1154 #endif
1155 if( n->is_MachCall() ) {
1156 MachCallNode *mcall = n->as_MachCall();
1157 phi_cnt = sched_call(block, phi_cnt, worklist, ready_cnt, mcall, next_call);
1158 continue;
1159 }
1160
1161 if (n->is_Mach() && n->as_Mach()->has_call()) {
1162 RegMask regs;
1163 regs.Insert(_matcher.c_frame_pointer());
1164 regs.OR(n->out_RegMask());
1165
1166 MachProjNode *proj = new MachProjNode( n, 1, RegMask::Empty, MachProjNode::fat_proj );
1167 map_node_to_block(proj, block);
1168 block->insert_node(proj, phi_cnt++);
1169
1170 add_call_kills(proj, regs, _matcher._c_reg_save_policy, false);
1171 }
1172
1173 // Children are now all ready
1174 for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) {
1175 Node* m = n->fast_out(i5); // Get user
1176 if (get_block_for_node(m) != block) {
1177 continue;
1178 }
1179 if( m->is_Phi() ) continue;
1180 if (m->_idx >= max_idx) { // new node, skip it
1181 assert(m->is_MachProj() && n->is_Mach() && n->as_Mach()->has_call(), "unexpected node types");
1182 continue;
1183 }
1184 int m_cnt = ready_cnt.at(m->_idx) - 1;
1185 ready_cnt.at_put(m->_idx, m_cnt);
1186 if( m_cnt == 0 )
1187 worklist.push(m);
1188 }
1189 }
1190
1191 if( phi_cnt != block->end_idx() ) {
1192 // did not schedule all. Retry, Bailout, or Die
1193 if (C->subsume_loads() == true && !C->failing()) {
1194 // Retry with subsume_loads == false
1195 // If this is the first failure, the sentinel string will "stick"
1196 // to the Compile object, and the C2Compiler will see it and retry.
1197 C->record_failure(C2Compiler::retry_no_subsuming_loads());
1198 } else {
1199 assert(false, "graph should be schedulable");
1200 }
1201 // assert( phi_cnt == end_idx(), "did not schedule all" );
1202 return false;
1203 }
1204
1205 if (OptoRegScheduling && block_size_threshold_ok) {
1206 _regalloc->compute_exit_block_pressure(block);
1207 block->_reg_pressure = _regalloc->_sched_int_pressure.final_pressure();
1208 block->_freg_pressure = _regalloc->_sched_float_pressure.final_pressure();
1209 }
1210
1211 #ifndef PRODUCT
1212 if (trace_opto_pipelining()) {
1213 tty->print_cr("#");
1214 tty->print_cr("# after schedule_local");
1215 for (uint i = 0;i < block->number_of_nodes();i++) {
1216 tty->print("# ");
1217 block->get_node(i)->dump();
1218 }
1219 tty->print_cr("# ");
1220
1221 if (OptoRegScheduling && block_size_threshold_ok) {
1222 tty->print_cr("# pressure info : %d", block->_pre_order);
1223 _regalloc->print_pressure_info(_regalloc->_sched_int_pressure, "int register info");
1224 _regalloc->print_pressure_info(_regalloc->_sched_float_pressure, "float register info");
1225 }
1226 tty->cr();
1227 }
1228 #endif
1229
1230 return true;
1231 }
1232
1233 //--------------------------catch_cleanup_fix_all_inputs-----------------------
1234 static void catch_cleanup_fix_all_inputs(Node *use, Node *old_def, Node *new_def) {
1235 for (uint l = 0; l < use->len(); l++) {
1236 if (use->in(l) == old_def) {
1237 if (l < use->req()) {
1238 use->set_req(l, new_def);
1239 } else {
1240 use->rm_prec(l);
1241 use->add_prec(new_def);
1242 l--;
1243 }
1244 }
1245 }
1246 }
1247
1248 //------------------------------catch_cleanup_find_cloned_def------------------
1249 Node* PhaseCFG::catch_cleanup_find_cloned_def(Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) {
1250 assert( use_blk != def_blk, "Inter-block cleanup only");
1251
1252 // The use is some block below the Catch. Find and return the clone of the def
1253 // that dominates the use. If there is no clone in a dominating block, then
1254 // create a phi for the def in a dominating block.
1255
1256 // Find which successor block dominates this use. The successor
1257 // blocks must all be single-entry (from the Catch only; I will have
1258 // split blocks to make this so), hence they all dominate.
1259 while( use_blk->_dom_depth > def_blk->_dom_depth+1 )
1260 use_blk = use_blk->_idom;
1261
1262 // Find the successor
1263 Node *fixup = nullptr;
1264
1265 uint j;
1266 for( j = 0; j < def_blk->_num_succs; j++ )
1267 if( use_blk == def_blk->_succs[j] )
1268 break;
1269
1270 if( j == def_blk->_num_succs ) {
1271 // Block at same level in dom-tree is not a successor. It needs a
1272 // PhiNode, the PhiNode uses from the def and IT's uses need fixup.
1273 Node_Array inputs;
1274 for(uint k = 1; k < use_blk->num_preds(); k++) {
1275 Block* block = get_block_for_node(use_blk->pred(k));
1276 inputs.map(k, catch_cleanup_find_cloned_def(block, def, def_blk, n_clone_idx));
1277 }
1278
1279 // Check to see if the use_blk already has an identical phi inserted.
1280 // If it exists, it will be at the first position since all uses of a
1281 // def are processed together.
1282 Node *phi = use_blk->get_node(1);
1283 if( phi->is_Phi() ) {
1284 fixup = phi;
1285 for (uint k = 1; k < use_blk->num_preds(); k++) {
1286 if (phi->in(k) != inputs[k]) {
1287 // Not a match
1288 fixup = nullptr;
1289 break;
1290 }
1291 }
1292 }
1293
1294 // If an existing PhiNode was not found, make a new one.
1295 if (fixup == nullptr) {
1296 Node *new_phi = PhiNode::make(use_blk->head(), def);
1297 use_blk->insert_node(new_phi, 1);
1298 map_node_to_block(new_phi, use_blk);
1299 for (uint k = 1; k < use_blk->num_preds(); k++) {
1300 new_phi->set_req(k, inputs[k]);
1301 }
1302 fixup = new_phi;
1303 }
1304
1305 } else {
1306 // Found the use just below the Catch. Make it use the clone.
1307 fixup = use_blk->get_node(n_clone_idx);
1308 }
1309
1310 return fixup;
1311 }
1312
1313 //--------------------------catch_cleanup_intra_block--------------------------
1314 // Fix all input edges in use that reference "def". The use is in the same
1315 // block as the def and both have been cloned in each successor block.
1316 static void catch_cleanup_intra_block(Node *use, Node *def, Block *blk, int beg, int n_clone_idx) {
1317
1318 // Both the use and def have been cloned. For each successor block,
1319 // get the clone of the use, and make its input the clone of the def
1320 // found in that block.
1321
1322 uint use_idx = blk->find_node(use);
1323 uint offset_idx = use_idx - beg;
1324 for( uint k = 0; k < blk->_num_succs; k++ ) {
1325 // Get clone in each successor block
1326 Block *sb = blk->_succs[k];
1327 Node *clone = sb->get_node(offset_idx+1);
1328 assert( clone->Opcode() == use->Opcode(), "" );
1329
1330 // Make use-clone reference the def-clone
1331 catch_cleanup_fix_all_inputs(clone, def, sb->get_node(n_clone_idx));
1332 }
1333 }
1334
1335 //------------------------------catch_cleanup_inter_block---------------------
1336 // Fix all input edges in use that reference "def". The use is in a different
1337 // block than the def.
1338 void PhaseCFG::catch_cleanup_inter_block(Node *use, Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) {
1339 if( !use_blk ) return; // Can happen if the use is a precedence edge
1340
1341 Node *new_def = catch_cleanup_find_cloned_def(use_blk, def, def_blk, n_clone_idx);
1342 catch_cleanup_fix_all_inputs(use, def, new_def);
1343 }
1344
1345 //------------------------------call_catch_cleanup-----------------------------
1346 // If we inserted any instructions between a Call and his CatchNode,
1347 // clone the instructions on all paths below the Catch.
1348 void PhaseCFG::call_catch_cleanup(Block* block) {
1349
1350 // End of region to clone
1351 uint end = block->end_idx();
1352 if( !block->get_node(end)->is_Catch() ) return;
1353 // Start of region to clone
1354 uint beg = end;
1355 while(!block->get_node(beg-1)->is_MachProj() ||
1356 !block->get_node(beg-1)->in(0)->is_MachCall() ) {
1357 beg--;
1358 assert(beg > 0,"Catch cleanup walking beyond block boundary");
1359 }
1360 // Range of inserted instructions is [beg, end)
1361 if( beg == end ) return;
1362
1363 // Clone along all Catch output paths. Clone area between the 'beg' and
1364 // 'end' indices.
1365 for( uint i = 0; i < block->_num_succs; i++ ) {
1366 Block *sb = block->_succs[i];
1367 // Clone the entire area; ignoring the edge fixup for now.
1368 for( uint j = end; j > beg; j-- ) {
1369 Node *clone = block->get_node(j-1)->clone();
1370 sb->insert_node(clone, 1);
1371 map_node_to_block(clone, sb);
1372 if (clone->needs_anti_dependence_check()) {
1373 insert_anti_dependences(sb, clone);
1374 }
1375 }
1376 }
1377
1378
1379 // Fixup edges. Check the def-use info per cloned Node
1380 for(uint i2 = beg; i2 < end; i2++ ) {
1381 uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block
1382 Node *n = block->get_node(i2); // Node that got cloned
1383 // Need DU safe iterator because of edge manipulation in calls.
1384 Unique_Node_List* out = new Unique_Node_List();
1385 for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) {
1386 out->push(n->fast_out(j1));
1387 }
1388 uint max = out->size();
1389 for (uint j = 0; j < max; j++) {// For all users
1390 Node *use = out->pop();
1391 Block *buse = get_block_for_node(use);
1392 if( use->is_Phi() ) {
1393 for( uint k = 1; k < use->req(); k++ )
1394 if( use->in(k) == n ) {
1395 Block* b = get_block_for_node(buse->pred(k));
1396 Node *fixup = catch_cleanup_find_cloned_def(b, n, block, n_clone_idx);
1397 use->set_req(k, fixup);
1398 }
1399 } else {
1400 if (block == buse) {
1401 catch_cleanup_intra_block(use, n, block, beg, n_clone_idx);
1402 } else {
1403 catch_cleanup_inter_block(use, buse, n, block, n_clone_idx);
1404 }
1405 }
1406 } // End for all users
1407
1408 } // End of for all Nodes in cloned area
1409
1410 // Remove the now-dead cloned ops
1411 for(uint i3 = beg; i3 < end; i3++ ) {
1412 block->get_node(beg)->disconnect_inputs(C);
1413 block->remove_node(beg);
1414 }
1415
1416 // If the successor blocks have a CreateEx node, move it back to the top
1417 for (uint i4 = 0; i4 < block->_num_succs; i4++) {
1418 Block *sb = block->_succs[i4];
1419 uint new_cnt = end - beg;
1420 // Remove any newly created, but dead, nodes by traversing their schedule
1421 // backwards. Here, a dead node is a node whose only outputs (if any) are
1422 // unused projections.
1423 for (uint j = new_cnt; j > 0; j--) {
1424 Node *n = sb->get_node(j);
1425 // Individual projections are examined together with all siblings when
1426 // their parent is visited.
1427 if (n->is_Proj()) {
1428 continue;
1429 }
1430 bool dead = true;
1431 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1432 Node* out = n->fast_out(i);
1433 // n is live if it has a non-projection output or a used projection.
1434 if (!out->is_Proj() || out->outcnt() > 0) {
1435 dead = false;
1436 break;
1437 }
1438 }
1439 if (dead) {
1440 // n's only outputs (if any) are unused projections scheduled next to n
1441 // (see PhaseCFG::select()). Remove these projections backwards.
1442 for (uint k = j + n->outcnt(); k > j; k--) {
1443 Node* proj = sb->get_node(k);
1444 assert(proj->is_Proj() && proj->in(0) == n,
1445 "projection should correspond to dead node");
1446 proj->disconnect_inputs(C);
1447 sb->remove_node(k);
1448 new_cnt--;
1449 }
1450 // Now remove the node itself.
1451 n->disconnect_inputs(C);
1452 sb->remove_node(j);
1453 new_cnt--;
1454 }
1455 }
1456 // If any newly created nodes remain, move the CreateEx node to the top
1457 if (new_cnt > 0) {
1458 Node *cex = sb->get_node(1+new_cnt);
1459 if( cex->is_Mach() && cex->as_Mach()->ideal_Opcode() == Op_CreateEx ) {
1460 sb->remove_node(1+new_cnt);
1461 sb->insert_node(cex, 1);
1462 }
1463 }
1464 }
1465 }
--- EOF ---