1 /*
2 * Copyright (c) 1998, 2015, 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 "memory/allocation.inline.hpp"
27 #include "opto/ad.hpp"
28 #include "opto/block.hpp"
29 #include "opto/c2compiler.hpp"
30 #include "opto/callnode.hpp"
31 #include "opto/cfgnode.hpp"
32 #include "opto/machnode.hpp"
33 #include "opto/runtime.hpp"
34 #include "runtime/sharedRuntime.hpp"
35
36 // Optimization - Graph Style
37
38 // Check whether val is not-null-decoded compressed oop,
39 // i.e. will grab into the base of the heap if it represents NULL.
40 static bool accesses_heap_base_zone(Node *val) {
41 if (Universe::narrow_oop_base() > 0) { // Implies UseCompressedOops.
42 if (val && val->is_Mach()) {
43 if (val->as_Mach()->ideal_Opcode() == Op_DecodeN) {
44 // This assumes all Decodes with TypePtr::NotNull are matched to nodes that
45 // decode NULL to point to the heap base (Decode_NN).
46 if (val->bottom_type()->is_oopptr()->ptr() == TypePtr::NotNull) {
47 return true;
48 }
49 }
50 // Must recognize load operation with Decode matched in memory operand.
51 // We should not reach here exept for PPC/AIX, as os::zero_page_read_protected()
52 // returns true everywhere else. On PPC, no such memory operands
53 // exist, therefore we did not yet implement a check for such operands.
54 NOT_AIX(Unimplemented());
55 }
56 }
57 return false;
58 }
59
60 static bool needs_explicit_null_check_for_read(Node *val) {
61 // On some OSes (AIX) the page at address 0 is only write protected.
62 // If so, only Store operations will trap.
63 if (os::zero_page_read_protected()) {
64 return false; // Implicit null check will work.
65 }
66 // Also a read accessing the base of a heap-based compressed heap will trap.
67 if (accesses_heap_base_zone(val) && // Hits the base zone page.
68 Universe::narrow_oop_use_implicit_null_checks()) { // Base zone page is protected.
69 return false;
70 }
71
72 return true;
73 }
74
75 //------------------------------implicit_null_check----------------------------
76 // Detect implicit-null-check opportunities. Basically, find NULL checks
77 // with suitable memory ops nearby. Use the memory op to do the NULL check.
78 // I can generate a memory op if there is not one nearby.
79 // The proj is the control projection for the not-null case.
80 // The val is the pointer being checked for nullness or
81 // decodeHeapOop_not_null node if it did not fold into address.
82 void PhaseCFG::implicit_null_check(Block* block, Node *proj, Node *val, int allowed_reasons) {
83 // Assume if null check need for 0 offset then always needed
84 // Intel solaris doesn't support any null checks yet and no
85 // mechanism exists (yet) to set the switches at an os_cpu level
86 if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return;
87
88 // Make sure the ptr-is-null path appears to be uncommon!
89 float f = block->end()->as_MachIf()->_prob;
90 if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f;
91 if( f > PROB_UNLIKELY_MAG(4) ) return;
92
93 uint bidx = 0; // Capture index of value into memop
94 bool was_store; // Memory op is a store op
95
96 // Get the successor block for if the test ptr is non-null
97 Block* not_null_block; // this one goes with the proj
98 Block* null_block;
99 if (block->get_node(block->number_of_nodes()-1) == proj) {
100 null_block = block->_succs[0];
101 not_null_block = block->_succs[1];
102 } else {
103 assert(block->get_node(block->number_of_nodes()-2) == proj, "proj is one or the other");
104 not_null_block = block->_succs[0];
105 null_block = block->_succs[1];
106 }
107 while (null_block->is_Empty() == Block::empty_with_goto) {
108 null_block = null_block->_succs[0];
109 }
110
111 // Search the exception block for an uncommon trap.
112 // (See Parse::do_if and Parse::do_ifnull for the reason
113 // we need an uncommon trap. Briefly, we need a way to
114 // detect failure of this optimization, as in 6366351.)
115 {
116 bool found_trap = false;
117 for (uint i1 = 0; i1 < null_block->number_of_nodes(); i1++) {
118 Node* nn = null_block->get_node(i1);
119 if (nn->is_MachCall() &&
120 nn->as_MachCall()->entry_point() == SharedRuntime::uncommon_trap_blob()->entry_point()) {
121 const Type* trtype = nn->in(TypeFunc::Parms)->bottom_type();
122 if (trtype->isa_int() && trtype->is_int()->is_con()) {
123 jint tr_con = trtype->is_int()->get_con();
124 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(tr_con);
125 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(tr_con);
126 assert((int)reason < (int)BitsPerInt, "recode bit map");
127 if (is_set_nth_bit(allowed_reasons, (int) reason)
128 && action != Deoptimization::Action_none) {
129 // This uncommon trap is sure to recompile, eventually.
130 // When that happens, C->too_many_traps will prevent
131 // this transformation from happening again.
132 found_trap = true;
133 }
134 }
135 break;
136 }
137 }
138 if (!found_trap) {
139 // We did not find an uncommon trap.
140 return;
141 }
142 }
143
144 // Check for decodeHeapOop_not_null node which did not fold into address
145 bool is_decoden = ((intptr_t)val) & 1;
146 val = (Node*)(((intptr_t)val) & ~1);
147
148 assert(!is_decoden || (val->in(0) == NULL) && val->is_Mach() &&
149 (val->as_Mach()->ideal_Opcode() == Op_DecodeN), "sanity");
150
151 // Search the successor block for a load or store who's base value is also
152 // the tested value. There may be several.
153 Node_List *out = new Node_List(Thread::current()->resource_area());
154 MachNode *best = NULL; // Best found so far
155 for (DUIterator i = val->outs(); val->has_out(i); i++) {
156 Node *m = val->out(i);
157 if( !m->is_Mach() ) continue;
158 MachNode *mach = m->as_Mach();
159 was_store = false;
160 int iop = mach->ideal_Opcode();
161 switch( iop ) {
162 case Op_LoadB:
163 case Op_LoadUB:
164 case Op_LoadUS:
165 case Op_LoadD:
166 case Op_LoadF:
167 case Op_LoadI:
168 case Op_LoadL:
169 case Op_LoadP:
170 case Op_LoadN:
171 case Op_LoadS:
172 case Op_LoadKlass:
173 case Op_LoadNKlass:
174 case Op_LoadRange:
175 case Op_LoadD_unaligned:
176 case Op_LoadL_unaligned:
177 case Op_ShenandoahReadBarrier:
178 case Op_ShenandoahWriteBarrier:
179 assert(mach->in(2) == val, "should be address");
180 break;
181 case Op_StoreB:
182 case Op_StoreC:
183 case Op_StoreCM:
184 case Op_StoreD:
185 case Op_StoreF:
186 case Op_StoreI:
187 case Op_StoreL:
188 case Op_StoreP:
189 case Op_StoreN:
190 case Op_StoreNKlass:
191 was_store = true; // Memory op is a store op
192 // Stores will have their address in slot 2 (memory in slot 1).
193 // If the value being nul-checked is in another slot, it means we
194 // are storing the checked value, which does NOT check the value!
195 if( mach->in(2) != val ) continue;
196 break; // Found a memory op?
197 case Op_StrComp:
198 case Op_StrEquals:
199 case Op_StrIndexOf:
200 case Op_AryEq:
201 case Op_EncodeISOArray:
202 // Not a legit memory op for implicit null check regardless of
203 // embedded loads
204 continue;
205 default: // Also check for embedded loads
206 if( !mach->needs_anti_dependence_check() )
207 continue; // Not an memory op; skip it
208 if( must_clone[iop] ) {
209 // Do not move nodes which produce flags because
210 // RA will try to clone it to place near branch and
211 // it will cause recompilation, see clone_node().
212 continue;
213 }
214 {
215 // Check that value is used in memory address in
216 // instructions with embedded load (CmpP val1,(val2+off)).
217 Node* base;
218 Node* index;
219 const MachOper* oper = mach->memory_inputs(base, index);
220 if (oper == NULL || oper == (MachOper*)-1) {
221 continue; // Not an memory op; skip it
222 }
223 if (val == base ||
224 val == index && val->bottom_type()->isa_narrowoop()) {
225 break; // Found it
226 } else {
227 continue; // Skip it
228 }
229 }
230 break;
231 }
232
233 // On some OSes (AIX) the page at address 0 is only write protected.
234 // If so, only Store operations will trap.
235 // But a read accessing the base of a heap-based compressed heap will trap.
236 if (!was_store && needs_explicit_null_check_for_read(val)) {
237 continue;
238 }
239
240 // check if the offset is not too high for implicit exception
241 {
242 intptr_t offset = 0;
243 const TypePtr *adr_type = NULL; // Do not need this return value here
244 const Node* base = mach->get_base_and_disp(offset, adr_type);
245 if (base == NULL || base == NodeSentinel) {
246 // Narrow oop address doesn't have base, only index
247 if( val->bottom_type()->isa_narrowoop() &&
248 MacroAssembler::needs_explicit_null_check(offset) )
249 continue; // Give up if offset is beyond page size
250 // cannot reason about it; is probably not implicit null exception
251 } else {
252 const TypePtr* tptr;
253 if (UseCompressedOops && (Universe::narrow_oop_shift() == 0 ||
254 Universe::narrow_klass_shift() == 0)) {
255 // 32-bits narrow oop can be the base of address expressions
256 tptr = base->get_ptr_type();
257 } else {
258 // only regular oops are expected here
259 tptr = base->bottom_type()->is_ptr();
260 }
261 // Give up if offset is not a compile-time constant
262 if( offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot )
263 continue;
264 offset += tptr->_offset; // correct if base is offseted
265 if( MacroAssembler::needs_explicit_null_check(offset) )
266 continue; // Give up is reference is beyond 4K page size
267 }
268 }
269
270 // Check ctrl input to see if the null-check dominates the memory op
271 Block *cb = get_block_for_node(mach);
272 cb = cb->_idom; // Always hoist at least 1 block
273 if( !was_store ) { // Stores can be hoisted only one block
274 while( cb->_dom_depth > (block->_dom_depth + 1))
275 cb = cb->_idom; // Hoist loads as far as we want
276 // The non-null-block should dominate the memory op, too. Live
277 // range spilling will insert a spill in the non-null-block if it is
278 // needs to spill the memory op for an implicit null check.
279 if (cb->_dom_depth == (block->_dom_depth + 1)) {
280 if (cb != not_null_block) continue;
281 cb = cb->_idom;
282 }
283 }
284 if( cb != block ) continue;
285
286 // Found a memory user; see if it can be hoisted to check-block
287 uint vidx = 0; // Capture index of value into memop
288 uint j;
289 for( j = mach->req()-1; j > 0; j-- ) {
290 if( mach->in(j) == val ) {
291 vidx = j;
292 // Ignore DecodeN val which could be hoisted to where needed.
293 if( is_decoden ) continue;
294 }
295 // Block of memory-op input
296 Block *inb = get_block_for_node(mach->in(j));
297 Block *b = block; // Start from nul check
298 while( b != inb && b->_dom_depth > inb->_dom_depth )
299 b = b->_idom; // search upwards for input
300 // See if input dominates null check
301 if( b != inb )
302 break;
303 }
304 if( j > 0 )
305 continue;
306 Block *mb = get_block_for_node(mach);
307 // Hoisting stores requires more checks for the anti-dependence case.
308 // Give up hoisting if we have to move the store past any load.
309 if( was_store ) {
310 Block *b = mb; // Start searching here for a local load
311 // mach use (faulting) trying to hoist
312 // n might be blocker to hoisting
313 while( b != block ) {
314 uint k;
315 for( k = 1; k < b->number_of_nodes(); k++ ) {
316 Node *n = b->get_node(k);
317 if( n->needs_anti_dependence_check() &&
318 n->in(LoadNode::Memory) == mach->in(StoreNode::Memory) )
319 break; // Found anti-dependent load
320 }
321 if( k < b->number_of_nodes() )
322 break; // Found anti-dependent load
323 // Make sure control does not do a merge (would have to check allpaths)
324 if( b->num_preds() != 2 ) break;
325 b = get_block_for_node(b->pred(1)); // Move up to predecessor block
326 }
327 if( b != block ) continue;
328 }
329
330 // Make sure this memory op is not already being used for a NullCheck
331 Node *e = mb->end();
332 if( e->is_MachNullCheck() && e->in(1) == mach )
333 continue; // Already being used as a NULL check
334
335 // Found a candidate! Pick one with least dom depth - the highest
336 // in the dom tree should be closest to the null check.
337 if (best == NULL || get_block_for_node(mach)->_dom_depth < get_block_for_node(best)->_dom_depth) {
338 best = mach;
339 bidx = vidx;
340 }
341 }
342 // No candidate!
343 if (best == NULL) {
344 return;
345 }
346
347 // ---- Found an implicit null check
348 extern int implicit_null_checks;
349 implicit_null_checks++;
350
351 if( is_decoden ) {
352 // Check if we need to hoist decodeHeapOop_not_null first.
353 Block *valb = get_block_for_node(val);
354 if( block != valb && block->_dom_depth < valb->_dom_depth ) {
355 // Hoist it up to the end of the test block.
356 valb->find_remove(val);
357 block->add_inst(val);
358 map_node_to_block(val, block);
359 // DecodeN on x86 may kill flags. Check for flag-killing projections
360 // that also need to be hoisted.
361 for (DUIterator_Fast jmax, j = val->fast_outs(jmax); j < jmax; j++) {
362 Node* n = val->fast_out(j);
363 if( n->is_MachProj() ) {
364 get_block_for_node(n)->find_remove(n);
365 block->add_inst(n);
366 map_node_to_block(n, block);
367 }
368 }
369 }
370 }
371 // Hoist the memory candidate up to the end of the test block.
372 Block *old_block = get_block_for_node(best);
373 old_block->find_remove(best);
374 block->add_inst(best);
375 map_node_to_block(best, block);
376
377 // Move the control dependence
378 if (best->in(0) && best->in(0) == old_block->head())
379 best->set_req(0, block->head());
380
381 // Check for flag-killing projections that also need to be hoisted
382 // Should be DU safe because no edge updates.
383 for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) {
384 Node* n = best->fast_out(j);
385 if( n->is_MachProj() || n->Opcode() == Op_ShenandoahWBMemProj) {
386 get_block_for_node(n)->find_remove(n);
387 block->add_inst(n);
388 map_node_to_block(n, block);
389 }
390 }
391
392 // proj==Op_True --> ne test; proj==Op_False --> eq test.
393 // One of two graph shapes got matched:
394 // (IfTrue (If (Bool NE (CmpP ptr NULL))))
395 // (IfFalse (If (Bool EQ (CmpP ptr NULL))))
396 // NULL checks are always branch-if-eq. If we see a IfTrue projection
397 // then we are replacing a 'ne' test with a 'eq' NULL check test.
398 // We need to flip the projections to keep the same semantics.
399 if( proj->Opcode() == Op_IfTrue ) {
400 // Swap order of projections in basic block to swap branch targets
401 Node *tmp1 = block->get_node(block->end_idx()+1);
402 Node *tmp2 = block->get_node(block->end_idx()+2);
403 block->map_node(tmp2, block->end_idx()+1);
404 block->map_node(tmp1, block->end_idx()+2);
405 Node *tmp = new Node(C->top()); // Use not NULL input
406 tmp1->replace_by(tmp);
407 tmp2->replace_by(tmp1);
408 tmp->replace_by(tmp2);
409 tmp->destruct();
410 }
411
412 // Remove the existing null check; use a new implicit null check instead.
413 // Since schedule-local needs precise def-use info, we need to correct
414 // it as well.
415 Node *old_tst = proj->in(0);
416 MachNode *nul_chk = new MachNullCheckNode(old_tst->in(0),best,bidx);
417 block->map_node(nul_chk, block->end_idx());
418 map_node_to_block(nul_chk, block);
419 // Redirect users of old_test to nul_chk
420 for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2)
421 old_tst->last_out(i2)->set_req(0, nul_chk);
422 // Clean-up any dead code
423 for (uint i3 = 0; i3 < old_tst->req(); i3++) {
424 Node* in = old_tst->in(i3);
425 old_tst->set_req(i3, NULL);
426 if (in->outcnt() == 0) {
427 // Remove dead input node
428 in->disconnect_inputs(NULL, C);
429 block->find_remove(in);
430 }
431 }
432
433 latency_from_uses(nul_chk);
434 latency_from_uses(best);
435 }
436
437
438 //------------------------------select-----------------------------------------
439 // Select a nice fellow from the worklist to schedule next. If there is only
440 // one choice, then use it. Projections take top priority for correctness
441 // reasons - if I see a projection, then it is next. There are a number of
442 // other special cases, for instructions that consume condition codes, et al.
443 // These are chosen immediately. Some instructions are required to immediately
444 // precede the last instruction in the block, and these are taken last. Of the
445 // remaining cases (most), choose the instruction with the greatest latency
446 // (that is, the most number of pseudo-cycles required to the end of the
447 // routine). If there is a tie, choose the instruction with the most inputs.
448 Node* PhaseCFG::select(Block* block, Node_List &worklist, GrowableArray<int> &ready_cnt, VectorSet &next_call, uint sched_slot) {
449
450 // If only a single entry on the stack, use it
451 uint cnt = worklist.size();
452 if (cnt == 1) {
453 Node *n = worklist[0];
454 worklist.map(0,worklist.pop());
455 return n;
456 }
457
458 uint choice = 0; // Bigger is most important
459 uint latency = 0; // Bigger is scheduled first
460 uint score = 0; // Bigger is better
461 int idx = -1; // Index in worklist
462 int cand_cnt = 0; // Candidate count
463
464 for( uint i=0; i<cnt; i++ ) { // Inspect entire worklist
465 // Order in worklist is used to break ties.
466 // See caller for how this is used to delay scheduling
467 // of induction variable increments to after the other
468 // uses of the phi are scheduled.
469 Node *n = worklist[i]; // Get Node on worklist
470
471 int iop = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : 0;
472 if( n->is_Proj() || // Projections always win
473 n->Opcode()== Op_Con || // So does constant 'Top'
474 iop == Op_CreateEx || // Create-exception must start block
475 iop == Op_CheckCastPP
476 ) {
477 worklist.map(i,worklist.pop());
478 return n;
479 }
480
481 // Final call in a block must be adjacent to 'catch'
482 Node *e = block->end();
483 if( e->is_Catch() && e->in(0)->in(0) == n )
484 continue;
485
486 // Memory op for an implicit null check has to be at the end of the block
487 if( e->is_MachNullCheck() && e->in(1) == n )
488 continue;
489
490 // Schedule IV increment last.
491 if (e->is_Mach() && e->as_Mach()->ideal_Opcode() == Op_CountedLoopEnd &&
492 e->in(1)->in(1) == n && n->is_iteratively_computed())
493 continue;
494
495 uint n_choice = 2;
496
497 // See if this instruction is consumed by a branch. If so, then (as the
498 // branch is the last instruction in the basic block) force it to the
499 // end of the basic block
500 if ( must_clone[iop] ) {
501 // See if any use is a branch
502 bool found_machif = false;
503
504 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
505 Node* use = n->fast_out(j);
506
507 // The use is a conditional branch, make them adjacent
508 if (use->is_MachIf() && get_block_for_node(use) == block) {
509 found_machif = true;
510 break;
511 }
512
513 // More than this instruction pending for successor to be ready,
514 // don't choose this if other opportunities are ready
515 if (ready_cnt.at(use->_idx) > 1)
516 n_choice = 1;
517 }
518
519 // loop terminated, prefer not to use this instruction
520 if (found_machif)
521 continue;
522 }
523
524 // See if this has a predecessor that is "must_clone", i.e. sets the
525 // condition code. If so, choose this first
526 for (uint j = 0; j < n->req() ; j++) {
527 Node *inn = n->in(j);
528 if (inn) {
529 if (inn->is_Mach() && must_clone[inn->as_Mach()->ideal_Opcode()] ) {
530 n_choice = 3;
531 break;
532 }
533 }
534 }
535
536 // MachTemps should be scheduled last so they are near their uses
537 if (n->is_MachTemp()) {
538 n_choice = 1;
539 }
540
541 uint n_latency = get_latency_for_node(n);
542 uint n_score = n->req(); // Many inputs get high score to break ties
543
544 // Keep best latency found
545 cand_cnt++;
546 if (choice < n_choice ||
547 (choice == n_choice &&
548 ((StressLCM && Compile::randomized_select(cand_cnt)) ||
549 (!StressLCM &&
550 (latency < n_latency ||
551 (latency == n_latency &&
552 (score < n_score))))))) {
553 choice = n_choice;
554 latency = n_latency;
555 score = n_score;
556 idx = i; // Also keep index in worklist
557 }
558 } // End of for all ready nodes in worklist
559
560 assert(idx >= 0, "index should be set");
561 Node *n = worklist[(uint)idx]; // Get the winner
562
563 worklist.map((uint)idx, worklist.pop()); // Compress worklist
564 return n;
565 }
566
567
568 //------------------------------set_next_call----------------------------------
569 void PhaseCFG::set_next_call(Block* block, Node* n, VectorSet& next_call) {
570 if( next_call.test_set(n->_idx) ) return;
571 for( uint i=0; i<n->len(); i++ ) {
572 Node *m = n->in(i);
573 if( !m ) continue; // must see all nodes in block that precede call
574 if (get_block_for_node(m) == block) {
575 set_next_call(block, m, next_call);
576 }
577 }
578 }
579
580 //------------------------------needed_for_next_call---------------------------
581 // Set the flag 'next_call' for each Node that is needed for the next call to
582 // be scheduled. This flag lets me bias scheduling so Nodes needed for the
583 // next subroutine call get priority - basically it moves things NOT needed
584 // for the next call till after the call. This prevents me from trying to
585 // carry lots of stuff live across a call.
586 void PhaseCFG::needed_for_next_call(Block* block, Node* this_call, VectorSet& next_call) {
587 // Find the next control-defining Node in this block
588 Node* call = NULL;
589 for (DUIterator_Fast imax, i = this_call->fast_outs(imax); i < imax; i++) {
590 Node* m = this_call->fast_out(i);
591 if (get_block_for_node(m) == block && // Local-block user
592 m != this_call && // Not self-start node
593 m->is_MachCall()) {
594 call = m;
595 break;
596 }
597 }
598 if (call == NULL) return; // No next call (e.g., block end is near)
599 // Set next-call for all inputs to this call
600 set_next_call(block, call, next_call);
601 }
602
603 //------------------------------add_call_kills-------------------------------------
604 // helper function that adds caller save registers to MachProjNode
605 static void add_call_kills(MachProjNode *proj, RegMask& regs, const char* save_policy, bool exclude_soe) {
606 // Fill in the kill mask for the call
607 for( OptoReg::Name r = OptoReg::Name(0); r < _last_Mach_Reg; r=OptoReg::add(r,1) ) {
608 if( !regs.Member(r) ) { // Not already defined by the call
609 // Save-on-call register?
610 if ((save_policy[r] == 'C') ||
611 (save_policy[r] == 'A') ||
612 ((save_policy[r] == 'E') && exclude_soe)) {
613 proj->_rout.Insert(r);
614 }
615 }
616 }
617 }
618
619
620 //------------------------------sched_call-------------------------------------
621 uint PhaseCFG::sched_call(Block* block, uint node_cnt, Node_List& worklist, GrowableArray<int>& ready_cnt, MachCallNode* mcall, VectorSet& next_call) {
622 RegMask regs;
623
624 // Schedule all the users of the call right now. All the users are
625 // projection Nodes, so they must be scheduled next to the call.
626 // Collect all the defined registers.
627 for (DUIterator_Fast imax, i = mcall->fast_outs(imax); i < imax; i++) {
628 Node* n = mcall->fast_out(i);
629 assert( n->is_MachProj(), "" );
630 int n_cnt = ready_cnt.at(n->_idx)-1;
631 ready_cnt.at_put(n->_idx, n_cnt);
632 assert( n_cnt == 0, "" );
633 // Schedule next to call
634 block->map_node(n, node_cnt++);
635 // Collect defined registers
636 regs.OR(n->out_RegMask());
637 // Check for scheduling the next control-definer
638 if( n->bottom_type() == Type::CONTROL )
639 // Warm up next pile of heuristic bits
640 needed_for_next_call(block, n, next_call);
641
642 // Children of projections are now all ready
643 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
644 Node* m = n->fast_out(j); // Get user
645 if(get_block_for_node(m) != block) {
646 continue;
647 }
648 if( m->is_Phi() ) continue;
649 int m_cnt = ready_cnt.at(m->_idx)-1;
650 ready_cnt.at_put(m->_idx, m_cnt);
651 if( m_cnt == 0 )
652 worklist.push(m);
653 }
654
655 }
656
657 // Act as if the call defines the Frame Pointer.
658 // Certainly the FP is alive and well after the call.
659 regs.Insert(_matcher.c_frame_pointer());
660
661 // Set all registers killed and not already defined by the call.
662 uint r_cnt = mcall->tf()->range()->cnt();
663 int op = mcall->ideal_Opcode();
664 MachProjNode *proj = new MachProjNode( mcall, r_cnt+1, RegMask::Empty, MachProjNode::fat_proj );
665 map_node_to_block(proj, block);
666 block->insert_node(proj, node_cnt++);
667
668 // Select the right register save policy.
669 const char * save_policy;
670 switch (op) {
671 case Op_CallRuntime:
672 case Op_CallLeaf:
673 case Op_CallLeafNoFP:
674 // Calling C code so use C calling convention
675 save_policy = _matcher._c_reg_save_policy;
676 break;
677
678 case Op_CallStaticJava:
679 case Op_CallDynamicJava:
680 // Calling Java code so use Java calling convention
681 save_policy = _matcher._register_save_policy;
682 break;
683
684 default:
685 ShouldNotReachHere();
686 }
687
688 // When using CallRuntime mark SOE registers as killed by the call
689 // so values that could show up in the RegisterMap aren't live in a
690 // callee saved register since the register wouldn't know where to
691 // find them. CallLeaf and CallLeafNoFP are ok because they can't
692 // have debug info on them. Strictly speaking this only needs to be
693 // done for oops since idealreg2debugmask takes care of debug info
694 // references but there no way to handle oops differently than other
695 // pointers as far as the kill mask goes.
696 bool exclude_soe = op == Op_CallRuntime;
697
698 // If the call is a MethodHandle invoke, we need to exclude the
699 // register which is used to save the SP value over MH invokes from
700 // the mask. Otherwise this register could be used for
701 // deoptimization information.
702 if (op == Op_CallStaticJava) {
703 MachCallStaticJavaNode* mcallstaticjava = (MachCallStaticJavaNode*) mcall;
704 if (mcallstaticjava->_method_handle_invoke)
705 proj->_rout.OR(Matcher::method_handle_invoke_SP_save_mask());
706 }
707
708 add_call_kills(proj, regs, save_policy, exclude_soe);
709
710 return node_cnt;
711 }
712
713
714 //------------------------------schedule_local---------------------------------
715 // Topological sort within a block. Someday become a real scheduler.
716 bool PhaseCFG::schedule_local(Block* block, GrowableArray<int>& ready_cnt, VectorSet& next_call) {
717 // Already "sorted" are the block start Node (as the first entry), and
718 // the block-ending Node and any trailing control projections. We leave
719 // these alone. PhiNodes and ParmNodes are made to follow the block start
720 // Node. Everything else gets topo-sorted.
721
722 #ifndef PRODUCT
723 if (trace_opto_pipelining()) {
724 tty->print_cr("# --- schedule_local B%d, before: ---", block->_pre_order);
725 for (uint i = 0;i < block->number_of_nodes(); i++) {
726 tty->print("# ");
727 block->get_node(i)->fast_dump();
728 }
729 tty->print_cr("#");
730 }
731 #endif
732
733 // RootNode is already sorted
734 if (block->number_of_nodes() == 1) {
735 return true;
736 }
737
738 // Move PhiNodes and ParmNodes from 1 to cnt up to the start
739 uint node_cnt = block->end_idx();
740 uint phi_cnt = 1;
741 uint i;
742 for( i = 1; i<node_cnt; i++ ) { // Scan for Phi
743 Node *n = block->get_node(i);
744 if( n->is_Phi() || // Found a PhiNode or ParmNode
745 (n->is_Proj() && n->in(0) == block->head()) ) {
746 // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt
747 block->map_node(block->get_node(phi_cnt), i);
748 block->map_node(n, phi_cnt++); // swap Phi/Parm up front
749 } else { // All others
750 // Count block-local inputs to 'n'
751 uint cnt = n->len(); // Input count
752 uint local = 0;
753 for( uint j=0; j<cnt; j++ ) {
754 Node *m = n->in(j);
755 if( m && get_block_for_node(m) == block && !m->is_top() )
756 local++; // One more block-local input
757 }
758 ready_cnt.at_put(n->_idx, local); // Count em up
759
760 #ifdef ASSERT
761 if( UseConcMarkSweepGC || UseG1GC ) {
762 if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_StoreCM ) {
763 // Check the precedence edges
764 for (uint prec = n->req(); prec < n->len(); prec++) {
765 Node* oop_store = n->in(prec);
766 if (oop_store != NULL) {
767 assert(get_block_for_node(oop_store)->_dom_depth <= block->_dom_depth, "oop_store must dominate card-mark");
768 }
769 }
770 }
771 }
772 #endif
773
774 // A few node types require changing a required edge to a precedence edge
775 // before allocation.
776 if( n->is_Mach() && n->req() > TypeFunc::Parms &&
777 (n->as_Mach()->ideal_Opcode() == Op_MemBarAcquire ||
778 n->as_Mach()->ideal_Opcode() == Op_MemBarVolatile) ) {
779 // MemBarAcquire could be created without Precedent edge.
780 // del_req() replaces the specified edge with the last input edge
781 // and then removes the last edge. If the specified edge > number of
782 // edges the last edge will be moved outside of the input edges array
783 // and the edge will be lost. This is why this code should be
784 // executed only when Precedent (== TypeFunc::Parms) edge is present.
785 Node *x = n->in(TypeFunc::Parms);
786 n->del_req(TypeFunc::Parms);
787 n->add_prec(x);
788 }
789 }
790 }
791 for(uint i2=i; i2< block->number_of_nodes(); i2++ ) // Trailing guys get zapped count
792 ready_cnt.at_put(block->get_node(i2)->_idx, 0);
793
794 // All the prescheduled guys do not hold back internal nodes
795 uint i3;
796 for(i3 = 0; i3<phi_cnt; i3++ ) { // For all pre-scheduled
797 Node *n = block->get_node(i3); // Get pre-scheduled
798 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
799 Node* m = n->fast_out(j);
800 if (get_block_for_node(m) == block) { // Local-block user
801 int m_cnt = ready_cnt.at(m->_idx)-1;
802 ready_cnt.at_put(m->_idx, m_cnt); // Fix ready count
803 }
804 }
805 }
806
807 Node_List delay;
808 // Make a worklist
809 Node_List worklist;
810 for(uint i4=i3; i4<node_cnt; i4++ ) { // Put ready guys on worklist
811 Node *m = block->get_node(i4);
812 if( !ready_cnt.at(m->_idx) ) { // Zero ready count?
813 if (m->is_iteratively_computed()) {
814 // Push induction variable increments last to allow other uses
815 // of the phi to be scheduled first. The select() method breaks
816 // ties in scheduling by worklist order.
817 delay.push(m);
818 } else if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CreateEx) {
819 // Force the CreateEx to the top of the list so it's processed
820 // first and ends up at the start of the block.
821 worklist.insert(0, m);
822 } else {
823 worklist.push(m); // Then on to worklist!
824 }
825 }
826 }
827 while (delay.size()) {
828 Node* d = delay.pop();
829 worklist.push(d);
830 }
831
832 // Warm up the 'next_call' heuristic bits
833 needed_for_next_call(block, block->head(), next_call);
834
835 #ifndef PRODUCT
836 if (trace_opto_pipelining()) {
837 for (uint j=0; j< block->number_of_nodes(); j++) {
838 Node *n = block->get_node(j);
839 int idx = n->_idx;
840 tty->print("# ready cnt:%3d ", ready_cnt.at(idx));
841 tty->print("latency:%3d ", get_latency_for_node(n));
842 tty->print("%4d: %s\n", idx, n->Name());
843 }
844 }
845 #endif
846
847 uint max_idx = (uint)ready_cnt.length();
848 // Pull from worklist and schedule
849 while( worklist.size() ) { // Worklist is not ready
850
851 #ifndef PRODUCT
852 if (trace_opto_pipelining()) {
853 tty->print("# ready list:");
854 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
855 Node *n = worklist[i]; // Get Node on worklist
856 tty->print(" %d", n->_idx);
857 }
858 tty->cr();
859 }
860 #endif
861
862 // Select and pop a ready guy from worklist
863 Node* n = select(block, worklist, ready_cnt, next_call, phi_cnt);
864 block->map_node(n, phi_cnt++); // Schedule him next
865
866 #ifndef PRODUCT
867 if (trace_opto_pipelining()) {
868 tty->print("# select %d: %s", n->_idx, n->Name());
869 tty->print(", latency:%d", get_latency_for_node(n));
870 n->dump();
871 if (Verbose) {
872 tty->print("# ready list:");
873 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
874 Node *n = worklist[i]; // Get Node on worklist
875 tty->print(" %d", n->_idx);
876 }
877 tty->cr();
878 }
879 }
880
881 #endif
882 if( n->is_MachCall() ) {
883 MachCallNode *mcall = n->as_MachCall();
884 phi_cnt = sched_call(block, phi_cnt, worklist, ready_cnt, mcall, next_call);
885 continue;
886 }
887
888 if (n->is_Mach() && n->as_Mach()->has_call()) {
889 RegMask regs;
890 regs.Insert(_matcher.c_frame_pointer());
891 regs.OR(n->out_RegMask());
892
893 MachProjNode *proj = new MachProjNode( n, 1, RegMask::Empty, MachProjNode::fat_proj );
894 map_node_to_block(proj, block);
895 block->insert_node(proj, phi_cnt++);
896
897 add_call_kills(proj, regs, _matcher._c_reg_save_policy, false);
898 }
899
900 // Children are now all ready
901 for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) {
902 Node* m = n->fast_out(i5); // Get user
903 if (get_block_for_node(m) != block) {
904 continue;
905 }
906 if( m->is_Phi() ) continue;
907 if (m->_idx >= max_idx) { // new node, skip it
908 assert(m->is_MachProj() && n->is_Mach() && n->as_Mach()->has_call(), "unexpected node types");
909 continue;
910 }
911 int m_cnt = ready_cnt.at(m->_idx)-1;
912 ready_cnt.at_put(m->_idx, m_cnt);
913 if( m_cnt == 0 )
914 worklist.push(m);
915 }
916 }
917
918 if( phi_cnt != block->end_idx() ) {
919 // did not schedule all. Retry, Bailout, or Die
920 if (C->subsume_loads() == true && !C->failing()) {
921 // Retry with subsume_loads == false
922 // If this is the first failure, the sentinel string will "stick"
923 // to the Compile object, and the C2Compiler will see it and retry.
924 C->record_failure(C2Compiler::retry_no_subsuming_loads());
925 }
926 // assert( phi_cnt == end_idx(), "did not schedule all" );
927 return false;
928 }
929
930 #ifndef PRODUCT
931 if (trace_opto_pipelining()) {
932 tty->print_cr("#");
933 tty->print_cr("# after schedule_local");
934 for (uint i = 0;i < block->number_of_nodes();i++) {
935 tty->print("# ");
936 block->get_node(i)->fast_dump();
937 }
938 tty->cr();
939 }
940 #endif
941
942
943 return true;
944 }
945
946 //--------------------------catch_cleanup_fix_all_inputs-----------------------
947 static void catch_cleanup_fix_all_inputs(Node *use, Node *old_def, Node *new_def) {
948 for (uint l = 0; l < use->len(); l++) {
949 if (use->in(l) == old_def) {
950 if (l < use->req()) {
951 use->set_req(l, new_def);
952 } else {
953 use->rm_prec(l);
954 use->add_prec(new_def);
955 l--;
956 }
957 }
958 }
959 }
960
961 //------------------------------catch_cleanup_find_cloned_def------------------
962 Node* PhaseCFG::catch_cleanup_find_cloned_def(Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) {
963 assert( use_blk != def_blk, "Inter-block cleanup only");
964
965 // The use is some block below the Catch. Find and return the clone of the def
966 // that dominates the use. If there is no clone in a dominating block, then
967 // create a phi for the def in a dominating block.
968
969 // Find which successor block dominates this use. The successor
970 // blocks must all be single-entry (from the Catch only; I will have
971 // split blocks to make this so), hence they all dominate.
972 while( use_blk->_dom_depth > def_blk->_dom_depth+1 )
973 use_blk = use_blk->_idom;
974
975 // Find the successor
976 Node *fixup = NULL;
977
978 uint j;
979 for( j = 0; j < def_blk->_num_succs; j++ )
980 if( use_blk == def_blk->_succs[j] )
981 break;
982
983 if( j == def_blk->_num_succs ) {
984 // Block at same level in dom-tree is not a successor. It needs a
985 // PhiNode, the PhiNode uses from the def and IT's uses need fixup.
986 Node_Array inputs = new Node_List(Thread::current()->resource_area());
987 for(uint k = 1; k < use_blk->num_preds(); k++) {
988 Block* block = get_block_for_node(use_blk->pred(k));
989 inputs.map(k, catch_cleanup_find_cloned_def(block, def, def_blk, n_clone_idx));
990 }
991
992 // Check to see if the use_blk already has an identical phi inserted.
993 // If it exists, it will be at the first position since all uses of a
994 // def are processed together.
995 Node *phi = use_blk->get_node(1);
996 if( phi->is_Phi() ) {
997 fixup = phi;
998 for (uint k = 1; k < use_blk->num_preds(); k++) {
999 if (phi->in(k) != inputs[k]) {
1000 // Not a match
1001 fixup = NULL;
1002 break;
1003 }
1004 }
1005 }
1006
1007 // If an existing PhiNode was not found, make a new one.
1008 if (fixup == NULL) {
1009 Node *new_phi = PhiNode::make(use_blk->head(), def);
1010 use_blk->insert_node(new_phi, 1);
1011 map_node_to_block(new_phi, use_blk);
1012 for (uint k = 1; k < use_blk->num_preds(); k++) {
1013 new_phi->set_req(k, inputs[k]);
1014 }
1015 fixup = new_phi;
1016 }
1017
1018 } else {
1019 // Found the use just below the Catch. Make it use the clone.
1020 fixup = use_blk->get_node(n_clone_idx);
1021 }
1022
1023 return fixup;
1024 }
1025
1026 //--------------------------catch_cleanup_intra_block--------------------------
1027 // Fix all input edges in use that reference "def". The use is in the same
1028 // block as the def and both have been cloned in each successor block.
1029 static void catch_cleanup_intra_block(Node *use, Node *def, Block *blk, int beg, int n_clone_idx) {
1030
1031 // Both the use and def have been cloned. For each successor block,
1032 // get the clone of the use, and make its input the clone of the def
1033 // found in that block.
1034
1035 uint use_idx = blk->find_node(use);
1036 uint offset_idx = use_idx - beg;
1037 for( uint k = 0; k < blk->_num_succs; k++ ) {
1038 // Get clone in each successor block
1039 Block *sb = blk->_succs[k];
1040 Node *clone = sb->get_node(offset_idx+1);
1041 assert( clone->Opcode() == use->Opcode(), "" );
1042
1043 // Make use-clone reference the def-clone
1044 catch_cleanup_fix_all_inputs(clone, def, sb->get_node(n_clone_idx));
1045 }
1046 }
1047
1048 //------------------------------catch_cleanup_inter_block---------------------
1049 // Fix all input edges in use that reference "def". The use is in a different
1050 // block than the def.
1051 void PhaseCFG::catch_cleanup_inter_block(Node *use, Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) {
1052 if( !use_blk ) return; // Can happen if the use is a precedence edge
1053
1054 Node *new_def = catch_cleanup_find_cloned_def(use_blk, def, def_blk, n_clone_idx);
1055 catch_cleanup_fix_all_inputs(use, def, new_def);
1056 }
1057
1058 //------------------------------call_catch_cleanup-----------------------------
1059 // If we inserted any instructions between a Call and his CatchNode,
1060 // clone the instructions on all paths below the Catch.
1061 void PhaseCFG::call_catch_cleanup(Block* block) {
1062
1063 // End of region to clone
1064 uint end = block->end_idx();
1065 if( !block->get_node(end)->is_Catch() ) return;
1066 // Start of region to clone
1067 uint beg = end;
1068 while(!block->get_node(beg-1)->is_MachProj() ||
1069 !block->get_node(beg-1)->in(0)->is_MachCall() ) {
1070 beg--;
1071 assert(beg > 0,"Catch cleanup walking beyond block boundary");
1072 }
1073 // Range of inserted instructions is [beg, end)
1074 if( beg == end ) return;
1075
1076 // Clone along all Catch output paths. Clone area between the 'beg' and
1077 // 'end' indices.
1078 for( uint i = 0; i < block->_num_succs; i++ ) {
1079 Block *sb = block->_succs[i];
1080 // Clone the entire area; ignoring the edge fixup for now.
1081 for( uint j = end; j > beg; j-- ) {
1082 // It is safe here to clone a node with anti_dependence
1083 // since clones dominate on each path.
1084 Node *clone = block->get_node(j-1)->clone();
1085 sb->insert_node(clone, 1);
1086 map_node_to_block(clone, sb);
1087 }
1088 }
1089
1090
1091 // Fixup edges. Check the def-use info per cloned Node
1092 for(uint i2 = beg; i2 < end; i2++ ) {
1093 uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block
1094 Node *n = block->get_node(i2); // Node that got cloned
1095 // Need DU safe iterator because of edge manipulation in calls.
1096 Unique_Node_List *out = new Unique_Node_List(Thread::current()->resource_area());
1097 for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) {
1098 out->push(n->fast_out(j1));
1099 }
1100 uint max = out->size();
1101 for (uint j = 0; j < max; j++) {// For all users
1102 Node *use = out->pop();
1103 Block *buse = get_block_for_node(use);
1104 if( use->is_Phi() ) {
1105 for( uint k = 1; k < use->req(); k++ )
1106 if( use->in(k) == n ) {
1107 Block* b = get_block_for_node(buse->pred(k));
1108 Node *fixup = catch_cleanup_find_cloned_def(b, n, block, n_clone_idx);
1109 use->set_req(k, fixup);
1110 }
1111 } else {
1112 if (block == buse) {
1113 catch_cleanup_intra_block(use, n, block, beg, n_clone_idx);
1114 } else {
1115 catch_cleanup_inter_block(use, buse, n, block, n_clone_idx);
1116 }
1117 }
1118 } // End for all users
1119
1120 } // End of for all Nodes in cloned area
1121
1122 // Remove the now-dead cloned ops
1123 for(uint i3 = beg; i3 < end; i3++ ) {
1124 block->get_node(beg)->disconnect_inputs(NULL, C);
1125 block->remove_node(beg);
1126 }
1127
1128 // If the successor blocks have a CreateEx node, move it back to the top
1129 for(uint i4 = 0; i4 < block->_num_succs; i4++ ) {
1130 Block *sb = block->_succs[i4];
1131 uint new_cnt = end - beg;
1132 // Remove any newly created, but dead, nodes.
1133 for( uint j = new_cnt; j > 0; j-- ) {
1134 Node *n = sb->get_node(j);
1135 if (n->outcnt() == 0 &&
1136 (!n->is_Proj() || n->as_Proj()->in(0)->outcnt() == 1) ){
1137 n->disconnect_inputs(NULL, C);
1138 sb->remove_node(j);
1139 new_cnt--;
1140 }
1141 }
1142 // If any newly created nodes remain, move the CreateEx node to the top
1143 if (new_cnt > 0) {
1144 Node *cex = sb->get_node(1+new_cnt);
1145 if( cex->is_Mach() && cex->as_Mach()->ideal_Opcode() == Op_CreateEx ) {
1146 sb->remove_node(1+new_cnt);
1147 sb->insert_node(cex, 1);
1148 }
1149 }
1150 }
1151 }