1 /*
2 * Copyright (c) 1998, 2014, 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.
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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
35 // Optimization - Graph Style
36
37 // Check whether val is not-null-decoded compressed oop,
38 // i.e. will grab into the base of the heap if it represents NULL.
39 static bool accesses_heap_base_zone(Node *val) {
40 if (Universe::narrow_oop_base() > 0) { // Implies UseCompressedOops.
41 if (val && val->is_Mach()) {
42 if (val->as_Mach()->ideal_Opcode() == Op_DecodeN) {
43 // This assumes all Decodes with TypePtr::NotNull are matched to nodes that
44 // decode NULL to point to the heap base (Decode_NN).
45 if (val->bottom_type()->is_oopptr()->ptr() == TypePtr::NotNull) {
46 return true;
47 }
48 }
49 // Must recognize load operation with Decode matched in memory operand.
50 // We should not reach here exept for PPC/AIX, as os::zero_page_read_protected()
51 // returns true everywhere else. On PPC, no such memory operands
52 // exist, therefore we did not yet implement a check for such operands.
53 NOT_AIX(Unimplemented());
54 }
55 }
56 return false;
57 }
58
59 static bool needs_explicit_null_check_for_read(Node *val) {
60 // On some OSes (AIX) the page at address 0 is only write protected.
61 // If so, only Store operations will trap.
62 if (os::zero_page_read_protected()) {
63 return false; // Implicit null check will work.
64 }
65 // Also a read accessing the base of a heap-based compressed heap will trap.
66 if (accesses_heap_base_zone(val) && // Hits the base zone page.
67 Universe::narrow_oop_use_implicit_null_checks()) { // Base zone page is protected.
68 return false;
69 }
70
71 return true;
72 }
73
74 //------------------------------implicit_null_check----------------------------
75 // Detect implicit-null-check opportunities. Basically, find NULL checks
76 // with suitable memory ops nearby. Use the memory op to do the NULL check.
77 // I can generate a memory op if there is not one nearby.
78 // The proj is the control projection for the not-null case.
79 // The val is the pointer being checked for nullness or
80 // decodeHeapOop_not_null node if it did not fold into address.
81 void PhaseCFG::implicit_null_check(Block* block, Node *proj, Node *val, int allowed_reasons) {
82 // Assume if null check need for 0 offset then always needed
83 // Intel solaris doesn't support any null checks yet and no
84 // mechanism exists (yet) to set the switches at an os_cpu level
85 if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return;
86
87 // Make sure the ptr-is-null path appears to be uncommon!
88 float f = block->end()->as_MachIf()->_prob;
89 if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f;
90 if( f > PROB_UNLIKELY_MAG(4) ) return;
91
92 uint bidx = 0; // Capture index of value into memop
93 bool was_store; // Memory op is a store op
94
95 // Get the successor block for if the test ptr is non-null
96 Block* not_null_block; // this one goes with the proj
97 Block* null_block;
98 if (block->get_node(block->number_of_nodes()-1) == proj) {
99 null_block = block->_succs[0];
100 not_null_block = block->_succs[1];
101 } else {
102 assert(block->get_node(block->number_of_nodes()-2) == proj, "proj is one or the other");
103 not_null_block = block->_succs[0];
104 null_block = block->_succs[1];
105 }
106 while (null_block->is_Empty() == Block::empty_with_goto) {
107 null_block = null_block->_succs[0];
108 }
109
110 // Search the exception block for an uncommon trap.
111 // (See Parse::do_if and Parse::do_ifnull for the reason
112 // we need an uncommon trap. Briefly, we need a way to
113 // detect failure of this optimization, as in 6366351.)
114 {
115 bool found_trap = false;
116 for (uint i1 = 0; i1 < null_block->number_of_nodes(); i1++) {
117 Node* nn = null_block->get_node(i1);
118 if (nn->is_MachCall() &&
119 nn->as_MachCall()->entry_point() == SharedRuntime::uncommon_trap_blob()->entry_point()) {
120 const Type* trtype = nn->in(TypeFunc::Parms)->bottom_type();
121 if (trtype->isa_int() && trtype->is_int()->is_con()) {
122 jint tr_con = trtype->is_int()->get_con();
123 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(tr_con);
124 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(tr_con);
125 assert((int)reason < (int)BitsPerInt, "recode bit map");
126 if (is_set_nth_bit(allowed_reasons, (int) reason)
127 && action != Deoptimization::Action_none) {
128 // This uncommon trap is sure to recompile, eventually.
129 // When that happens, C->too_many_traps will prevent
130 // this transformation from happening again.
131 found_trap = true;
132 }
133 }
134 break;
135 }
136 }
137 if (!found_trap) {
138 // We did not find an uncommon trap.
139 return;
140 }
141 }
142
143 // Check for decodeHeapOop_not_null node which did not fold into address
144 bool is_decoden = ((intptr_t)val) & 1;
145 val = (Node*)(((intptr_t)val) & ~1);
146
147 assert(!is_decoden || (val->in(0) == NULL) && val->is_Mach() &&
148 (val->as_Mach()->ideal_Opcode() == Op_DecodeN), "sanity");
149
150 // Search the successor block for a load or store who's base value is also
151 // the tested value. There may be several.
152 Node_List *out = new Node_List(Thread::current()->resource_area());
153 MachNode *best = NULL; // Best found so far
154 for (DUIterator i = val->outs(); val->has_out(i); i++) {
155 Node *m = val->out(i);
156 if( !m->is_Mach() ) continue;
157 MachNode *mach = m->as_Mach();
158 was_store = false;
159 int iop = mach->ideal_Opcode();
160 switch( iop ) {
161 case Op_LoadB:
162 case Op_LoadUB:
163 case Op_LoadUS:
164 case Op_LoadD:
165 case Op_LoadF:
166 case Op_LoadI:
167 case Op_LoadL:
168 case Op_LoadP:
169 case Op_LoadN:
170 case Op_LoadS:
171 case Op_LoadKlass:
172 case Op_LoadNKlass:
173 case Op_LoadRange:
174 case Op_LoadD_unaligned:
175 case Op_LoadL_unaligned:
176 assert(mach->in(2) == val, "should be address");
177 break;
178 case Op_StoreB:
179 case Op_StoreC:
180 case Op_StoreCM:
181 case Op_StoreD:
182 case Op_StoreF:
183 case Op_StoreI:
184 case Op_StoreL:
185 case Op_StoreP:
186 case Op_StoreN:
187 case Op_StoreNKlass:
188 was_store = true; // Memory op is a store op
189 // Stores will have their address in slot 2 (memory in slot 1).
190 // If the value being nul-checked is in another slot, it means we
191 // are storing the checked value, which does NOT check the value!
192 if( mach->in(2) != val ) continue;
193 break; // Found a memory op?
194 case Op_StrComp:
195 case Op_StrEquals:
196 case Op_StrIndexOf:
197 case Op_AryEq:
198 case Op_EncodeISOArray:
199 // Not a legit memory op for implicit null check regardless of
200 // embedded loads
201 continue;
202 default: // Also check for embedded loads
203 if( !mach->needs_anti_dependence_check() )
204 continue; // Not an memory op; skip it
205 if( must_clone[iop] ) {
206 // Do not move nodes which produce flags because
207 // RA will try to clone it to place near branch and
208 // it will cause recompilation, see clone_node().
209 continue;
210 }
211 {
212 // Check that value is used in memory address in
213 // instructions with embedded load (CmpP val1,(val2+off)).
214 Node* base;
215 Node* index;
216 const MachOper* oper = mach->memory_inputs(base, index);
217 if (oper == NULL || oper == (MachOper*)-1) {
218 continue; // Not an memory op; skip it
219 }
220 if (val == base ||
221 val == index && val->bottom_type()->isa_narrowoop()) {
222 break; // Found it
223 } else {
224 continue; // Skip it
225 }
226 }
227 break;
228 }
229
230 // On some OSes (AIX) the page at address 0 is only write protected.
231 // If so, only Store operations will trap.
232 // But a read accessing the base of a heap-based compressed heap will trap.
233 if (!was_store && needs_explicit_null_check_for_read(val)) {
234 continue;
235 }
236
237 // check if the offset is not too high for implicit exception
238 {
239 intptr_t offset = 0;
240 const TypePtr *adr_type = NULL; // Do not need this return value here
241 const Node* base = mach->get_base_and_disp(offset, adr_type);
242 if (base == NULL || base == NodeSentinel) {
243 // Narrow oop address doesn't have base, only index
244 if( val->bottom_type()->isa_narrowoop() &&
245 MacroAssembler::needs_explicit_null_check(offset) )
246 continue; // Give up if offset is beyond page size
247 // cannot reason about it; is probably not implicit null exception
248 } else {
249 const TypePtr* tptr;
250 if (UseCompressedOops && (Universe::narrow_oop_shift() == 0 ||
251 Universe::narrow_klass_shift() == 0)) {
252 // 32-bits narrow oop can be the base of address expressions
253 tptr = base->get_ptr_type();
254 } else {
255 // only regular oops are expected here
256 tptr = base->bottom_type()->is_ptr();
257 }
258 // Give up if offset is not a compile-time constant
259 if( offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot )
260 continue;
261 offset += tptr->_offset; // correct if base is offseted
262 if( MacroAssembler::needs_explicit_null_check(offset) )
263 continue; // Give up is reference is beyond 4K page size
264 }
265 }
266
267 // Check ctrl input to see if the null-check dominates the memory op
268 Block *cb = get_block_for_node(mach);
269 cb = cb->_idom; // Always hoist at least 1 block
270 if( !was_store ) { // Stores can be hoisted only one block
271 while( cb->_dom_depth > (block->_dom_depth + 1))
272 cb = cb->_idom; // Hoist loads as far as we want
273 // The non-null-block should dominate the memory op, too. Live
274 // range spilling will insert a spill in the non-null-block if it is
275 // needs to spill the memory op for an implicit null check.
276 if (cb->_dom_depth == (block->_dom_depth + 1)) {
277 if (cb != not_null_block) continue;
278 cb = cb->_idom;
279 }
280 }
281 if( cb != block ) continue;
282
283 // Found a memory user; see if it can be hoisted to check-block
284 uint vidx = 0; // Capture index of value into memop
285 uint j;
286 for( j = mach->req()-1; j > 0; j-- ) {
287 if( mach->in(j) == val ) {
288 vidx = j;
289 // Ignore DecodeN val which could be hoisted to where needed.
290 if( is_decoden ) continue;
291 }
292 // Block of memory-op input
293 Block *inb = get_block_for_node(mach->in(j));
294 Block *b = block; // Start from nul check
295 while( b != inb && b->_dom_depth > inb->_dom_depth )
296 b = b->_idom; // search upwards for input
297 // See if input dominates null check
298 if( b != inb )
299 break;
300 }
301 if( j > 0 )
302 continue;
303 Block *mb = get_block_for_node(mach);
304 // Hoisting stores requires more checks for the anti-dependence case.
305 // Give up hoisting if we have to move the store past any load.
306 if( was_store ) {
307 Block *b = mb; // Start searching here for a local load
308 // mach use (faulting) trying to hoist
309 // n might be blocker to hoisting
310 while( b != block ) {
311 uint k;
312 for( k = 1; k < b->number_of_nodes(); k++ ) {
313 Node *n = b->get_node(k);
314 if( n->needs_anti_dependence_check() &&
315 n->in(LoadNode::Memory) == mach->in(StoreNode::Memory) )
316 break; // Found anti-dependent load
317 }
318 if( k < b->number_of_nodes() )
319 break; // Found anti-dependent load
320 // Make sure control does not do a merge (would have to check allpaths)
321 if( b->num_preds() != 2 ) break;
322 b = get_block_for_node(b->pred(1)); // Move up to predecessor block
323 }
324 if( b != block ) continue;
325 }
326
327 // Make sure this memory op is not already being used for a NullCheck
328 Node *e = mb->end();
329 if( e->is_MachNullCheck() && e->in(1) == mach )
330 continue; // Already being used as a NULL check
331
332 // Found a candidate! Pick one with least dom depth - the highest
333 // in the dom tree should be closest to the null check.
334 if (best == NULL || get_block_for_node(mach)->_dom_depth < get_block_for_node(best)->_dom_depth) {
335 best = mach;
336 bidx = vidx;
337 }
338 }
339 // No candidate!
340 if (best == NULL) {
341 return;
342 }
343
344 // ---- Found an implicit null check
345 extern int implicit_null_checks;
346 implicit_null_checks++;
347
348 if( is_decoden ) {
349 // Check if we need to hoist decodeHeapOop_not_null first.
350 Block *valb = get_block_for_node(val);
351 if( block != valb && block->_dom_depth < valb->_dom_depth ) {
352 // Hoist it up to the end of the test block.
353 valb->find_remove(val);
354 block->add_inst(val);
355 map_node_to_block(val, block);
356 // DecodeN on x86 may kill flags. Check for flag-killing projections
357 // that also need to be hoisted.
358 for (DUIterator_Fast jmax, j = val->fast_outs(jmax); j < jmax; j++) {
359 Node* n = val->fast_out(j);
360 if( n->is_MachProj() ) {
361 get_block_for_node(n)->find_remove(n);
362 block->add_inst(n);
363 map_node_to_block(n, block);
364 }
365 }
366 }
367 }
368 // Hoist the memory candidate up to the end of the test block.
369 Block *old_block = get_block_for_node(best);
370 old_block->find_remove(best);
371 block->add_inst(best);
372 map_node_to_block(best, block);
373
374 // Move the control dependence
375 if (best->in(0) && best->in(0) == old_block->head())
376 best->set_req(0, block->head());
377
378 // Check for flag-killing projections that also need to be hoisted
379 // Should be DU safe because no edge updates.
380 for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) {
381 Node* n = best->fast_out(j);
382 if( n->is_MachProj() ) {
383 get_block_for_node(n)->find_remove(n);
384 block->add_inst(n);
385 map_node_to_block(n, block);
386 }
387 }
388
389 // proj==Op_True --> ne test; proj==Op_False --> eq test.
390 // One of two graph shapes got matched:
391 // (IfTrue (If (Bool NE (CmpP ptr NULL))))
392 // (IfFalse (If (Bool EQ (CmpP ptr NULL))))
393 // NULL checks are always branch-if-eq. If we see a IfTrue projection
394 // then we are replacing a 'ne' test with a 'eq' NULL check test.
395 // We need to flip the projections to keep the same semantics.
396 if( proj->Opcode() == Op_IfTrue ) {
397 // Swap order of projections in basic block to swap branch targets
398 Node *tmp1 = block->get_node(block->end_idx()+1);
399 Node *tmp2 = block->get_node(block->end_idx()+2);
400 block->map_node(tmp2, block->end_idx()+1);
401 block->map_node(tmp1, block->end_idx()+2);
402 Node *tmp = new Node(C->top()); // Use not NULL input
403 tmp1->replace_by(tmp);
404 tmp2->replace_by(tmp1);
405 tmp->replace_by(tmp2);
406 tmp->destruct();
407 }
408
409 // Remove the existing null check; use a new implicit null check instead.
410 // Since schedule-local needs precise def-use info, we need to correct
411 // it as well.
412 Node *old_tst = proj->in(0);
413 MachNode *nul_chk = new MachNullCheckNode(old_tst->in(0),best,bidx);
414 block->map_node(nul_chk, block->end_idx());
415 map_node_to_block(nul_chk, block);
416 // Redirect users of old_test to nul_chk
417 for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2)
418 old_tst->last_out(i2)->set_req(0, nul_chk);
419 // Clean-up any dead code
420 for (uint i3 = 0; i3 < old_tst->req(); i3++) {
421 Node* in = old_tst->in(i3);
422 old_tst->set_req(i3, NULL);
423 if (in->outcnt() == 0) {
424 // Remove dead input node
425 in->disconnect_inputs(NULL, C);
426 block->find_remove(in);
427 }
428 }
429
430 latency_from_uses(nul_chk);
431 latency_from_uses(best);
432 }
433
434
435 //------------------------------select-----------------------------------------
436 // Select a nice fellow from the worklist to schedule next. If there is only
437 // one choice, then use it. Projections take top priority for correctness
438 // reasons - if I see a projection, then it is next. There are a number of
439 // other special cases, for instructions that consume condition codes, et al.
440 // These are chosen immediately. Some instructions are required to immediately
441 // precede the last instruction in the block, and these are taken last. Of the
442 // remaining cases (most), choose the instruction with the greatest latency
443 // (that is, the most number of pseudo-cycles required to the end of the
444 // routine). If there is a tie, choose the instruction with the most inputs.
445 Node* PhaseCFG::select(Block* block, Node_List &worklist, GrowableArray<int> &ready_cnt, VectorSet &next_call, uint sched_slot) {
446
447 // If only a single entry on the stack, use it
448 uint cnt = worklist.size();
449 if (cnt == 1) {
450 Node *n = worklist[0];
451 worklist.map(0,worklist.pop());
452 return n;
453 }
454
455 uint choice = 0; // Bigger is most important
456 uint latency = 0; // Bigger is scheduled first
457 uint score = 0; // Bigger is better
458 int idx = -1; // Index in worklist
459 int cand_cnt = 0; // Candidate count
460
461 for( uint i=0; i<cnt; i++ ) { // Inspect entire worklist
462 // Order in worklist is used to break ties.
463 // See caller for how this is used to delay scheduling
464 // of induction variable increments to after the other
465 // uses of the phi are scheduled.
466 Node *n = worklist[i]; // Get Node on worklist
467
468 int iop = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : 0;
469 if( n->is_Proj() || // Projections always win
470 n->Opcode()== Op_Con || // So does constant 'Top'
471 iop == Op_CreateEx || // Create-exception must start block
472 iop == Op_CheckCastPP
473 ) {
474 worklist.map(i,worklist.pop());
475 return n;
476 }
477
478 // Final call in a block must be adjacent to 'catch'
479 Node *e = block->end();
480 if( e->is_Catch() && e->in(0)->in(0) == n )
481 continue;
482
483 // Memory op for an implicit null check has to be at the end of the block
484 if( e->is_MachNullCheck() && e->in(1) == n )
485 continue;
486
487 // Schedule IV increment last.
488 if (e->is_Mach() && e->as_Mach()->ideal_Opcode() == Op_CountedLoopEnd &&
489 e->in(1)->in(1) == n && n->is_iteratively_computed())
490 continue;
491
492 uint n_choice = 2;
493
494 // See if this instruction is consumed by a branch. If so, then (as the
495 // branch is the last instruction in the basic block) force it to the
496 // end of the basic block
497 if ( must_clone[iop] ) {
498 // See if any use is a branch
499 bool found_machif = false;
500
501 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
502 Node* use = n->fast_out(j);
503
504 // The use is a conditional branch, make them adjacent
505 if (use->is_MachIf() && get_block_for_node(use) == block) {
506 found_machif = true;
507 break;
508 }
509
510 // More than this instruction pending for successor to be ready,
511 // don't choose this if other opportunities are ready
512 if (ready_cnt.at(use->_idx) > 1)
513 n_choice = 1;
514 }
515
516 // loop terminated, prefer not to use this instruction
517 if (found_machif)
518 continue;
519 }
520
521 // See if this has a predecessor that is "must_clone", i.e. sets the
522 // condition code. If so, choose this first
523 for (uint j = 0; j < n->req() ; j++) {
524 Node *inn = n->in(j);
525 if (inn) {
526 if (inn->is_Mach() && must_clone[inn->as_Mach()->ideal_Opcode()] ) {
527 n_choice = 3;
528 break;
529 }
530 }
531 }
532
533 // MachTemps should be scheduled last so they are near their uses
534 if (n->is_MachTemp()) {
535 n_choice = 1;
536 }
537
538 uint n_latency = get_latency_for_node(n);
539 uint n_score = n->req(); // Many inputs get high score to break ties
540
541 // Keep best latency found
542 cand_cnt++;
543 if (choice < n_choice ||
544 (choice == n_choice &&
545 ((StressLCM && Compile::randomized_select(cand_cnt)) ||
546 (!StressLCM &&
547 (latency < n_latency ||
548 (latency == n_latency &&
549 (score < n_score))))))) {
550 choice = n_choice;
551 latency = n_latency;
552 score = n_score;
553 idx = i; // Also keep index in worklist
554 }
555 } // End of for all ready nodes in worklist
556
557 assert(idx >= 0, "index should be set");
558 Node *n = worklist[(uint)idx]; // Get the winner
559
560 worklist.map((uint)idx, worklist.pop()); // Compress worklist
561 return n;
562 }
563
564
565 //------------------------------set_next_call----------------------------------
566 void PhaseCFG::set_next_call(Block* block, Node* n, VectorSet& next_call) {
567 if( next_call.test_set(n->_idx) ) return;
568 for( uint i=0; i<n->len(); i++ ) {
569 Node *m = n->in(i);
570 if( !m ) continue; // must see all nodes in block that precede call
571 if (get_block_for_node(m) == block) {
572 set_next_call(block, m, next_call);
573 }
574 }
575 }
576
577 //------------------------------needed_for_next_call---------------------------
578 // Set the flag 'next_call' for each Node that is needed for the next call to
579 // be scheduled. This flag lets me bias scheduling so Nodes needed for the
580 // next subroutine call get priority - basically it moves things NOT needed
581 // for the next call till after the call. This prevents me from trying to
582 // carry lots of stuff live across a call.
583 void PhaseCFG::needed_for_next_call(Block* block, Node* this_call, VectorSet& next_call) {
584 // Find the next control-defining Node in this block
585 Node* call = NULL;
586 for (DUIterator_Fast imax, i = this_call->fast_outs(imax); i < imax; i++) {
587 Node* m = this_call->fast_out(i);
588 if (get_block_for_node(m) == block && // Local-block user
589 m != this_call && // Not self-start node
590 m->is_MachCall()) {
591 call = m;
592 break;
593 }
594 }
595 if (call == NULL) return; // No next call (e.g., block end is near)
596 // Set next-call for all inputs to this call
597 set_next_call(block, call, next_call);
598 }
599
600 //------------------------------add_call_kills-------------------------------------
601 // helper function that adds caller save registers to MachProjNode
602 static void add_call_kills(MachProjNode *proj, RegMask& regs, const char* save_policy, bool exclude_soe) {
603 // Fill in the kill mask for the call
604 for( OptoReg::Name r = OptoReg::Name(0); r < _last_Mach_Reg; r=OptoReg::add(r,1) ) {
605 if( !regs.Member(r) ) { // Not already defined by the call
606 // Save-on-call register?
607 if ((save_policy[r] == 'C') ||
608 (save_policy[r] == 'A') ||
609 ((save_policy[r] == 'E') && exclude_soe)) {
610 proj->_rout.Insert(r);
611 }
612 }
613 }
614 }
615
616
617 //------------------------------sched_call-------------------------------------
618 uint PhaseCFG::sched_call(Block* block, uint node_cnt, Node_List& worklist, GrowableArray<int>& ready_cnt, MachCallNode* mcall, VectorSet& next_call) {
619 RegMask regs;
620
621 // Schedule all the users of the call right now. All the users are
622 // projection Nodes, so they must be scheduled next to the call.
623 // Collect all the defined registers.
624 for (DUIterator_Fast imax, i = mcall->fast_outs(imax); i < imax; i++) {
625 Node* n = mcall->fast_out(i);
626 assert( n->is_MachProj(), "" );
627 int n_cnt = ready_cnt.at(n->_idx)-1;
628 ready_cnt.at_put(n->_idx, n_cnt);
629 assert( n_cnt == 0, "" );
630 // Schedule next to call
631 block->map_node(n, node_cnt++);
632 // Collect defined registers
633 regs.OR(n->out_RegMask());
634 // Check for scheduling the next control-definer
635 if( n->bottom_type() == Type::CONTROL )
636 // Warm up next pile of heuristic bits
637 needed_for_next_call(block, n, next_call);
638
639 // Children of projections are now all ready
640 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
641 Node* m = n->fast_out(j); // Get user
642 if(get_block_for_node(m) != block) {
643 continue;
644 }
645 if( m->is_Phi() ) continue;
646 int m_cnt = ready_cnt.at(m->_idx)-1;
647 ready_cnt.at_put(m->_idx, m_cnt);
648 if( m_cnt == 0 )
649 worklist.push(m);
650 }
651
652 }
653
654 // Act as if the call defines the Frame Pointer.
655 // Certainly the FP is alive and well after the call.
656 regs.Insert(_matcher.c_frame_pointer());
657
658 // Set all registers killed and not already defined by the call.
659 uint r_cnt = mcall->tf()->range()->cnt();
660 int op = mcall->ideal_Opcode();
661 MachProjNode *proj = new MachProjNode( mcall, r_cnt+1, RegMask::Empty, MachProjNode::fat_proj );
662 map_node_to_block(proj, block);
663 block->insert_node(proj, node_cnt++);
664
665 // Select the right register save policy.
666 const char * save_policy;
667 switch (op) {
668 case Op_CallRuntime:
669 case Op_CallLeaf:
670 case Op_CallLeafNoFP:
671 // Calling C code so use C calling convention
672 save_policy = _matcher._c_reg_save_policy;
673 break;
674
675 case Op_CallStaticJava:
676 case Op_CallDynamicJava:
677 // Calling Java code so use Java calling convention
678 save_policy = _matcher._register_save_policy;
679 break;
680
681 default:
682 ShouldNotReachHere();
683 }
684
685 // When using CallRuntime mark SOE registers as killed by the call
686 // so values that could show up in the RegisterMap aren't live in a
687 // callee saved register since the register wouldn't know where to
688 // find them. CallLeaf and CallLeafNoFP are ok because they can't
689 // have debug info on them. Strictly speaking this only needs to be
690 // done for oops since idealreg2debugmask takes care of debug info
691 // references but there no way to handle oops differently than other
692 // pointers as far as the kill mask goes.
693 bool exclude_soe = op == Op_CallRuntime;
694
695 // If the call is a MethodHandle invoke, we need to exclude the
696 // register which is used to save the SP value over MH invokes from
697 // the mask. Otherwise this register could be used for
698 // deoptimization information.
699 if (op == Op_CallStaticJava) {
700 MachCallStaticJavaNode* mcallstaticjava = (MachCallStaticJavaNode*) mcall;
701 if (mcallstaticjava->_method_handle_invoke)
702 proj->_rout.OR(Matcher::method_handle_invoke_SP_save_mask());
703 }
704
705 add_call_kills(proj, regs, save_policy, exclude_soe);
706
707 return node_cnt;
708 }
709
710
711 //------------------------------schedule_local---------------------------------
712 // Topological sort within a block. Someday become a real scheduler.
713 bool PhaseCFG::schedule_local(Block* block, GrowableArray<int>& ready_cnt, VectorSet& next_call) {
714 // Already "sorted" are the block start Node (as the first entry), and
715 // the block-ending Node and any trailing control projections. We leave
716 // these alone. PhiNodes and ParmNodes are made to follow the block start
717 // Node. Everything else gets topo-sorted.
718
719 #ifndef PRODUCT
720 if (trace_opto_pipelining()) {
721 tty->print_cr("# --- schedule_local B%d, before: ---", block->_pre_order);
722 for (uint i = 0;i < block->number_of_nodes(); i++) {
723 tty->print("# ");
724 block->get_node(i)->fast_dump();
725 }
726 tty->print_cr("#");
727 }
728 #endif
729
730 // RootNode is already sorted
731 if (block->number_of_nodes() == 1) {
732 return true;
733 }
734
735 // Move PhiNodes and ParmNodes from 1 to cnt up to the start
736 uint node_cnt = block->end_idx();
737 uint phi_cnt = 1;
738 uint i;
739 for( i = 1; i<node_cnt; i++ ) { // Scan for Phi
740 Node *n = block->get_node(i);
741 if( n->is_Phi() || // Found a PhiNode or ParmNode
742 (n->is_Proj() && n->in(0) == block->head()) ) {
743 // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt
744 block->map_node(block->get_node(phi_cnt), i);
745 block->map_node(n, phi_cnt++); // swap Phi/Parm up front
746 } else { // All others
747 // Count block-local inputs to 'n'
748 uint cnt = n->len(); // Input count
749 uint local = 0;
750 for( uint j=0; j<cnt; j++ ) {
751 Node *m = n->in(j);
752 if( m && get_block_for_node(m) == block && !m->is_top() )
753 local++; // One more block-local input
754 }
755 ready_cnt.at_put(n->_idx, local); // Count em up
756
757 #ifdef ASSERT
758 if( UseConcMarkSweepGC || UseG1GC ) {
759 if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_StoreCM ) {
760 // Check the precedence edges
761 for (uint prec = n->req(); prec < n->len(); prec++) {
762 Node* oop_store = n->in(prec);
763 if (oop_store != NULL) {
764 assert(get_block_for_node(oop_store)->_dom_depth <= block->_dom_depth, "oop_store must dominate card-mark");
765 }
766 }
767 }
768 }
769 #endif
770
771 // A few node types require changing a required edge to a precedence edge
772 // before allocation.
773 if( n->is_Mach() && n->req() > TypeFunc::Parms &&
774 (n->as_Mach()->ideal_Opcode() == Op_MemBarAcquire ||
775 n->as_Mach()->ideal_Opcode() == Op_MemBarVolatile) ) {
776 // MemBarAcquire could be created without Precedent edge.
777 // del_req() replaces the specified edge with the last input edge
778 // and then removes the last edge. If the specified edge > number of
779 // edges the last edge will be moved outside of the input edges array
780 // and the edge will be lost. This is why this code should be
781 // executed only when Precedent (== TypeFunc::Parms) edge is present.
782 Node *x = n->in(TypeFunc::Parms);
783 n->del_req(TypeFunc::Parms);
784 n->add_prec(x);
785 }
786 }
787 }
788 for(uint i2=i; i2< block->number_of_nodes(); i2++ ) // Trailing guys get zapped count
789 ready_cnt.at_put(block->get_node(i2)->_idx, 0);
790
791 // All the prescheduled guys do not hold back internal nodes
792 uint i3;
793 for(i3 = 0; i3<phi_cnt; i3++ ) { // For all pre-scheduled
794 Node *n = block->get_node(i3); // Get pre-scheduled
795 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
796 Node* m = n->fast_out(j);
797 if (get_block_for_node(m) == block) { // Local-block user
798 int m_cnt = ready_cnt.at(m->_idx)-1;
799 ready_cnt.at_put(m->_idx, m_cnt); // Fix ready count
800 }
801 }
802 }
803
804 Node_List delay;
805 // Make a worklist
806 Node_List worklist;
807 for(uint i4=i3; i4<node_cnt; i4++ ) { // Put ready guys on worklist
808 Node *m = block->get_node(i4);
809 if( !ready_cnt.at(m->_idx) ) { // Zero ready count?
810 if (m->is_iteratively_computed()) {
811 // Push induction variable increments last to allow other uses
812 // of the phi to be scheduled first. The select() method breaks
813 // ties in scheduling by worklist order.
814 delay.push(m);
815 } else if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CreateEx) {
816 // Force the CreateEx to the top of the list so it's processed
817 // first and ends up at the start of the block.
818 worklist.insert(0, m);
819 } else {
820 worklist.push(m); // Then on to worklist!
821 }
822 }
823 }
824 while (delay.size()) {
825 Node* d = delay.pop();
826 worklist.push(d);
827 }
828
829 // Warm up the 'next_call' heuristic bits
830 needed_for_next_call(block, block->head(), next_call);
831
832 #ifndef PRODUCT
833 if (trace_opto_pipelining()) {
834 for (uint j=0; j< block->number_of_nodes(); j++) {
835 Node *n = block->get_node(j);
836 int idx = n->_idx;
837 tty->print("# ready cnt:%3d ", ready_cnt.at(idx));
838 tty->print("latency:%3d ", get_latency_for_node(n));
839 tty->print("%4d: %s\n", idx, n->Name());
840 }
841 }
842 #endif
843
844 uint max_idx = (uint)ready_cnt.length();
845 // Pull from worklist and schedule
846 while( worklist.size() ) { // Worklist is not ready
847
848 #ifndef PRODUCT
849 if (trace_opto_pipelining()) {
850 tty->print("# ready list:");
851 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
852 Node *n = worklist[i]; // Get Node on worklist
853 tty->print(" %d", n->_idx);
854 }
855 tty->cr();
856 }
857 #endif
858
859 // Select and pop a ready guy from worklist
860 Node* n = select(block, worklist, ready_cnt, next_call, phi_cnt);
861 block->map_node(n, phi_cnt++); // Schedule him next
862
863 #ifndef PRODUCT
864 if (trace_opto_pipelining()) {
865 tty->print("# select %d: %s", n->_idx, n->Name());
866 tty->print(", latency:%d", get_latency_for_node(n));
867 n->dump();
868 if (Verbose) {
869 tty->print("# ready list:");
870 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
871 Node *n = worklist[i]; // Get Node on worklist
872 tty->print(" %d", n->_idx);
873 }
874 tty->cr();
875 }
876 }
877
878 #endif
879 if( n->is_MachCall() ) {
880 MachCallNode *mcall = n->as_MachCall();
881 phi_cnt = sched_call(block, phi_cnt, worklist, ready_cnt, mcall, next_call);
882 continue;
883 }
884
885 if (n->is_Mach() && n->as_Mach()->has_call()) {
886 RegMask regs;
887 regs.Insert(_matcher.c_frame_pointer());
888 regs.OR(n->out_RegMask());
889
890 MachProjNode *proj = new MachProjNode( n, 1, RegMask::Empty, MachProjNode::fat_proj );
891 map_node_to_block(proj, block);
892 block->insert_node(proj, phi_cnt++);
893
894 add_call_kills(proj, regs, _matcher._c_reg_save_policy, false);
895 }
896
897 // Children are now all ready
898 for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) {
899 Node* m = n->fast_out(i5); // Get user
900 if (get_block_for_node(m) != block) {
901 continue;
902 }
903 if( m->is_Phi() ) continue;
904 if (m->_idx >= max_idx) { // new node, skip it
905 assert(m->is_MachProj() && n->is_Mach() && n->as_Mach()->has_call(), "unexpected node types");
906 continue;
907 }
908 int m_cnt = ready_cnt.at(m->_idx)-1;
909 ready_cnt.at_put(m->_idx, m_cnt);
910 if( m_cnt == 0 )
911 worklist.push(m);
912 }
913 }
914
915 if( phi_cnt != block->end_idx() ) {
916 // did not schedule all. Retry, Bailout, or Die
917 if (C->subsume_loads() == true && !C->failing()) {
918 // Retry with subsume_loads == false
919 // If this is the first failure, the sentinel string will "stick"
920 // to the Compile object, and the C2Compiler will see it and retry.
921 C->record_failure(C2Compiler::retry_no_subsuming_loads());
922 }
923 // assert( phi_cnt == end_idx(), "did not schedule all" );
924 return false;
925 }
926
927 #ifndef PRODUCT
928 if (trace_opto_pipelining()) {
929 tty->print_cr("#");
930 tty->print_cr("# after schedule_local");
931 for (uint i = 0;i < block->number_of_nodes();i++) {
932 tty->print("# ");
933 block->get_node(i)->fast_dump();
934 }
935 tty->cr();
936 }
937 #endif
938
939
940 return true;
941 }
942
943 //--------------------------catch_cleanup_fix_all_inputs-----------------------
944 static void catch_cleanup_fix_all_inputs(Node *use, Node *old_def, Node *new_def) {
945 for (uint l = 0; l < use->len(); l++) {
946 if (use->in(l) == old_def) {
947 if (l < use->req()) {
948 use->set_req(l, new_def);
949 } else {
950 use->rm_prec(l);
951 use->add_prec(new_def);
952 l--;
953 }
954 }
955 }
956 }
957
958 //------------------------------catch_cleanup_find_cloned_def------------------
959 Node* PhaseCFG::catch_cleanup_find_cloned_def(Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) {
960 assert( use_blk != def_blk, "Inter-block cleanup only");
961
962 // The use is some block below the Catch. Find and return the clone of the def
963 // that dominates the use. If there is no clone in a dominating block, then
964 // create a phi for the def in a dominating block.
965
966 // Find which successor block dominates this use. The successor
967 // blocks must all be single-entry (from the Catch only; I will have
968 // split blocks to make this so), hence they all dominate.
969 while( use_blk->_dom_depth > def_blk->_dom_depth+1 )
970 use_blk = use_blk->_idom;
971
972 // Find the successor
973 Node *fixup = NULL;
974
975 uint j;
976 for( j = 0; j < def_blk->_num_succs; j++ )
977 if( use_blk == def_blk->_succs[j] )
978 break;
979
980 if( j == def_blk->_num_succs ) {
981 // Block at same level in dom-tree is not a successor. It needs a
982 // PhiNode, the PhiNode uses from the def and IT's uses need fixup.
983 Node_Array inputs = new Node_List(Thread::current()->resource_area());
984 for(uint k = 1; k < use_blk->num_preds(); k++) {
985 Block* block = get_block_for_node(use_blk->pred(k));
986 inputs.map(k, catch_cleanup_find_cloned_def(block, def, def_blk, n_clone_idx));
987 }
988
989 // Check to see if the use_blk already has an identical phi inserted.
990 // If it exists, it will be at the first position since all uses of a
991 // def are processed together.
992 Node *phi = use_blk->get_node(1);
993 if( phi->is_Phi() ) {
994 fixup = phi;
995 for (uint k = 1; k < use_blk->num_preds(); k++) {
996 if (phi->in(k) != inputs[k]) {
997 // Not a match
998 fixup = NULL;
999 break;
1000 }
1001 }
1002 }
1003
1004 // If an existing PhiNode was not found, make a new one.
1005 if (fixup == NULL) {
1006 Node *new_phi = PhiNode::make(use_blk->head(), def);
1007 use_blk->insert_node(new_phi, 1);
1008 map_node_to_block(new_phi, use_blk);
1009 for (uint k = 1; k < use_blk->num_preds(); k++) {
1010 new_phi->set_req(k, inputs[k]);
1011 }
1012 fixup = new_phi;
1013 }
1014
1015 } else {
1016 // Found the use just below the Catch. Make it use the clone.
1017 fixup = use_blk->get_node(n_clone_idx);
1018 }
1019
1020 return fixup;
1021 }
1022
1023 //--------------------------catch_cleanup_intra_block--------------------------
1024 // Fix all input edges in use that reference "def". The use is in the same
1025 // block as the def and both have been cloned in each successor block.
1026 static void catch_cleanup_intra_block(Node *use, Node *def, Block *blk, int beg, int n_clone_idx) {
1027
1028 // Both the use and def have been cloned. For each successor block,
1029 // get the clone of the use, and make its input the clone of the def
1030 // found in that block.
1031
1032 uint use_idx = blk->find_node(use);
1033 uint offset_idx = use_idx - beg;
1034 for( uint k = 0; k < blk->_num_succs; k++ ) {
1035 // Get clone in each successor block
1036 Block *sb = blk->_succs[k];
1037 Node *clone = sb->get_node(offset_idx+1);
1038 assert( clone->Opcode() == use->Opcode(), "" );
1039
1040 // Make use-clone reference the def-clone
1041 catch_cleanup_fix_all_inputs(clone, def, sb->get_node(n_clone_idx));
1042 }
1043 }
1044
1045 //------------------------------catch_cleanup_inter_block---------------------
1046 // Fix all input edges in use that reference "def". The use is in a different
1047 // block than the def.
1048 void PhaseCFG::catch_cleanup_inter_block(Node *use, Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) {
1049 if( !use_blk ) return; // Can happen if the use is a precedence edge
1050
1051 Node *new_def = catch_cleanup_find_cloned_def(use_blk, def, def_blk, n_clone_idx);
1052 catch_cleanup_fix_all_inputs(use, def, new_def);
1053 }
1054
1055 //------------------------------call_catch_cleanup-----------------------------
1056 // If we inserted any instructions between a Call and his CatchNode,
1057 // clone the instructions on all paths below the Catch.
1058 void PhaseCFG::call_catch_cleanup(Block* block) {
1059
1060 // End of region to clone
1061 uint end = block->end_idx();
1062 if( !block->get_node(end)->is_Catch() ) return;
1063 // Start of region to clone
1064 uint beg = end;
1065 while(!block->get_node(beg-1)->is_MachProj() ||
1066 !block->get_node(beg-1)->in(0)->is_MachCall() ) {
1067 beg--;
1068 assert(beg > 0,"Catch cleanup walking beyond block boundary");
1069 }
1070 // Range of inserted instructions is [beg, end)
1071 if( beg == end ) return;
1072
1073 // Clone along all Catch output paths. Clone area between the 'beg' and
1074 // 'end' indices.
1075 for( uint i = 0; i < block->_num_succs; i++ ) {
1076 Block *sb = block->_succs[i];
1077 // Clone the entire area; ignoring the edge fixup for now.
1078 for( uint j = end; j > beg; j-- ) {
1079 // It is safe here to clone a node with anti_dependence
1080 // since clones dominate on each path.
1081 Node *clone = block->get_node(j-1)->clone();
1082 sb->insert_node(clone, 1);
1083 map_node_to_block(clone, sb);
1084 }
1085 }
1086
1087
1088 // Fixup edges. Check the def-use info per cloned Node
1089 for(uint i2 = beg; i2 < end; i2++ ) {
1090 uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block
1091 Node *n = block->get_node(i2); // Node that got cloned
1092 // Need DU safe iterator because of edge manipulation in calls.
1093 Unique_Node_List *out = new Unique_Node_List(Thread::current()->resource_area());
1094 for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) {
1095 out->push(n->fast_out(j1));
1096 }
1097 uint max = out->size();
1098 for (uint j = 0; j < max; j++) {// For all users
1099 Node *use = out->pop();
1100 Block *buse = get_block_for_node(use);
1101 if( use->is_Phi() ) {
1102 for( uint k = 1; k < use->req(); k++ )
1103 if( use->in(k) == n ) {
1104 Block* b = get_block_for_node(buse->pred(k));
1105 Node *fixup = catch_cleanup_find_cloned_def(b, n, block, n_clone_idx);
1106 use->set_req(k, fixup);
1107 }
1108 } else {
1109 if (block == buse) {
1110 catch_cleanup_intra_block(use, n, block, beg, n_clone_idx);
1111 } else {
1112 catch_cleanup_inter_block(use, buse, n, block, n_clone_idx);
1113 }
1114 }
1115 } // End for all users
1116
1117 } // End of for all Nodes in cloned area
1118
1119 // Remove the now-dead cloned ops
1120 for(uint i3 = beg; i3 < end; i3++ ) {
1121 block->get_node(beg)->disconnect_inputs(NULL, C);
1122 block->remove_node(beg);
1123 }
1124
1125 // If the successor blocks have a CreateEx node, move it back to the top
1126 for(uint i4 = 0; i4 < block->_num_succs; i4++ ) {
1127 Block *sb = block->_succs[i4];
1128 uint new_cnt = end - beg;
1129 // Remove any newly created, but dead, nodes.
1130 for( uint j = new_cnt; j > 0; j-- ) {
1131 Node *n = sb->get_node(j);
1132 if (n->outcnt() == 0 &&
1133 (!n->is_Proj() || n->as_Proj()->in(0)->outcnt() == 1) ){
1134 n->disconnect_inputs(NULL, C);
1135 sb->remove_node(j);
1136 new_cnt--;
1137 }
1138 }
1139 // If any newly created nodes remain, move the CreateEx node to the top
1140 if (new_cnt > 0) {
1141 Node *cex = sb->get_node(1+new_cnt);
1142 if( cex->is_Mach() && cex->as_Mach()->ideal_Opcode() == Op_CreateEx ) {
1143 sb->remove_node(1+new_cnt);
1144 sb->insert_node(cex, 1);
1145 }
1146 }
1147 }
1148 }