1 /*
2 * Copyright (c) 1998, 2009, 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
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7 * published by the Free Software Foundation.
8 *
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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).
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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23 */
24
25 // Optimization - Graph Style
26
27 #include "incls/_precompiled.incl"
28 #include "incls/_lcm.cpp.incl"
29
30 //------------------------------implicit_null_check----------------------------
31 // Detect implicit-null-check opportunities. Basically, find NULL checks
32 // with suitable memory ops nearby. Use the memory op to do the NULL check.
33 // I can generate a memory op if there is not one nearby.
34 // The proj is the control projection for the not-null case.
35 // The val is the pointer being checked for nullness or
36 // decodeHeapOop_not_null node if it did not fold into address.
37 void Block::implicit_null_check(PhaseCFG *cfg, Node *proj, Node *val, int allowed_reasons) {
38 // Assume if null check need for 0 offset then always needed
39 // Intel solaris doesn't support any null checks yet and no
40 // mechanism exists (yet) to set the switches at an os_cpu level
41 if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return;
42
43 // Make sure the ptr-is-null path appears to be uncommon!
44 float f = end()->as_MachIf()->_prob;
45 if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f;
46 if( f > PROB_UNLIKELY_MAG(4) ) return;
47
48 uint bidx = 0; // Capture index of value into memop
49 bool was_store; // Memory op is a store op
50
51 // Get the successor block for if the test ptr is non-null
52 Block* not_null_block; // this one goes with the proj
53 Block* null_block;
54 if (_nodes[_nodes.size()-1] == proj) {
55 null_block = _succs[0];
56 not_null_block = _succs[1];
57 } else {
58 assert(_nodes[_nodes.size()-2] == proj, "proj is one or the other");
59 not_null_block = _succs[0];
60 null_block = _succs[1];
61 }
62 while (null_block->is_Empty() == Block::empty_with_goto) {
63 null_block = null_block->_succs[0];
64 }
65
66 // Search the exception block for an uncommon trap.
67 // (See Parse::do_if and Parse::do_ifnull for the reason
68 // we need an uncommon trap. Briefly, we need a way to
69 // detect failure of this optimization, as in 6366351.)
70 {
71 bool found_trap = false;
72 for (uint i1 = 0; i1 < null_block->_nodes.size(); i1++) {
73 Node* nn = null_block->_nodes[i1];
74 if (nn->is_MachCall() &&
75 nn->as_MachCall()->entry_point() ==
76 SharedRuntime::uncommon_trap_blob()->instructions_begin()) {
77 const Type* trtype = nn->in(TypeFunc::Parms)->bottom_type();
78 if (trtype->isa_int() && trtype->is_int()->is_con()) {
79 jint tr_con = trtype->is_int()->get_con();
80 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(tr_con);
81 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(tr_con);
82 assert((int)reason < (int)BitsPerInt, "recode bit map");
83 if (is_set_nth_bit(allowed_reasons, (int) reason)
84 && action != Deoptimization::Action_none) {
85 // This uncommon trap is sure to recompile, eventually.
86 // When that happens, C->too_many_traps will prevent
87 // this transformation from happening again.
88 found_trap = true;
89 }
90 }
91 break;
92 }
93 }
94 if (!found_trap) {
95 // We did not find an uncommon trap.
96 return;
97 }
98 }
99
100 // Check for decodeHeapOop_not_null node which did not fold into address
101 bool is_decoden = ((intptr_t)val) & 1;
102 val = (Node*)(((intptr_t)val) & ~1);
103
104 assert(!is_decoden || (val->in(0) == NULL) && val->is_Mach() &&
105 (val->as_Mach()->ideal_Opcode() == Op_DecodeN), "sanity");
106
107 // Search the successor block for a load or store who's base value is also
108 // the tested value. There may be several.
109 Node_List *out = new Node_List(Thread::current()->resource_area());
110 MachNode *best = NULL; // Best found so far
111 for (DUIterator i = val->outs(); val->has_out(i); i++) {
112 Node *m = val->out(i);
113 if( !m->is_Mach() ) continue;
114 MachNode *mach = m->as_Mach();
115 was_store = false;
116 switch( mach->ideal_Opcode() ) {
117 case Op_LoadB:
118 case Op_LoadUS:
119 case Op_LoadD:
120 case Op_LoadF:
121 case Op_LoadI:
122 case Op_LoadL:
123 case Op_LoadP:
124 case Op_LoadN:
125 case Op_LoadS:
126 case Op_LoadKlass:
127 case Op_LoadNKlass:
128 case Op_LoadRange:
129 case Op_LoadD_unaligned:
130 case Op_LoadL_unaligned:
131 assert(mach->in(2) == val, "should be address");
132 break;
133 case Op_StoreB:
134 case Op_StoreC:
135 case Op_StoreCM:
136 case Op_StoreD:
137 case Op_StoreF:
138 case Op_StoreI:
139 case Op_StoreL:
140 case Op_StoreP:
141 case Op_StoreN:
142 was_store = true; // Memory op is a store op
143 // Stores will have their address in slot 2 (memory in slot 1).
144 // If the value being nul-checked is in another slot, it means we
145 // are storing the checked value, which does NOT check the value!
146 if( mach->in(2) != val ) continue;
147 break; // Found a memory op?
148 case Op_StrComp:
149 case Op_StrEquals:
150 case Op_StrIndexOf:
151 case Op_AryEq:
152 // Not a legit memory op for implicit null check regardless of
153 // embedded loads
154 continue;
155 default: // Also check for embedded loads
156 if( !mach->needs_anti_dependence_check() )
157 continue; // Not an memory op; skip it
158 {
159 // Check that value is used in memory address in
160 // instructions with embedded load (CmpP val1,(val2+off)).
161 Node* base;
162 Node* index;
163 const MachOper* oper = mach->memory_inputs(base, index);
164 if (oper == NULL || oper == (MachOper*)-1) {
165 continue; // Not an memory op; skip it
166 }
167 if (val == base ||
168 val == index && val->bottom_type()->isa_narrowoop()) {
169 break; // Found it
170 } else {
171 continue; // Skip it
172 }
173 }
174 break;
175 }
176 // check if the offset is not too high for implicit exception
177 {
178 intptr_t offset = 0;
179 const TypePtr *adr_type = NULL; // Do not need this return value here
180 const Node* base = mach->get_base_and_disp(offset, adr_type);
181 if (base == NULL || base == NodeSentinel) {
182 // Narrow oop address doesn't have base, only index
183 if( val->bottom_type()->isa_narrowoop() &&
184 MacroAssembler::needs_explicit_null_check(offset) )
185 continue; // Give up if offset is beyond page size
186 // cannot reason about it; is probably not implicit null exception
187 } else {
188 const TypePtr* tptr;
189 if (UseCompressedOops && Universe::narrow_oop_shift() == 0) {
190 // 32-bits narrow oop can be the base of address expressions
191 tptr = base->bottom_type()->make_ptr();
192 } else {
193 // only regular oops are expected here
194 tptr = base->bottom_type()->is_ptr();
195 }
196 // Give up if offset is not a compile-time constant
197 if( offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot )
198 continue;
199 offset += tptr->_offset; // correct if base is offseted
200 if( MacroAssembler::needs_explicit_null_check(offset) )
201 continue; // Give up is reference is beyond 4K page size
202 }
203 }
204
205 // Check ctrl input to see if the null-check dominates the memory op
206 Block *cb = cfg->_bbs[mach->_idx];
207 cb = cb->_idom; // Always hoist at least 1 block
208 if( !was_store ) { // Stores can be hoisted only one block
209 while( cb->_dom_depth > (_dom_depth + 1))
210 cb = cb->_idom; // Hoist loads as far as we want
211 // The non-null-block should dominate the memory op, too. Live
212 // range spilling will insert a spill in the non-null-block if it is
213 // needs to spill the memory op for an implicit null check.
214 if (cb->_dom_depth == (_dom_depth + 1)) {
215 if (cb != not_null_block) continue;
216 cb = cb->_idom;
217 }
218 }
219 if( cb != this ) continue;
220
221 // Found a memory user; see if it can be hoisted to check-block
222 uint vidx = 0; // Capture index of value into memop
223 uint j;
224 for( j = mach->req()-1; j > 0; j-- ) {
225 if( mach->in(j) == val ) {
226 vidx = j;
227 // Ignore DecodeN val which could be hoisted to where needed.
228 if( is_decoden ) continue;
229 }
230 // Block of memory-op input
231 Block *inb = cfg->_bbs[mach->in(j)->_idx];
232 Block *b = this; // Start from nul check
233 while( b != inb && b->_dom_depth > inb->_dom_depth )
234 b = b->_idom; // search upwards for input
235 // See if input dominates null check
236 if( b != inb )
237 break;
238 }
239 if( j > 0 )
240 continue;
241 Block *mb = cfg->_bbs[mach->_idx];
242 // Hoisting stores requires more checks for the anti-dependence case.
243 // Give up hoisting if we have to move the store past any load.
244 if( was_store ) {
245 Block *b = mb; // Start searching here for a local load
246 // mach use (faulting) trying to hoist
247 // n might be blocker to hoisting
248 while( b != this ) {
249 uint k;
250 for( k = 1; k < b->_nodes.size(); k++ ) {
251 Node *n = b->_nodes[k];
252 if( n->needs_anti_dependence_check() &&
253 n->in(LoadNode::Memory) == mach->in(StoreNode::Memory) )
254 break; // Found anti-dependent load
255 }
256 if( k < b->_nodes.size() )
257 break; // Found anti-dependent load
258 // Make sure control does not do a merge (would have to check allpaths)
259 if( b->num_preds() != 2 ) break;
260 b = cfg->_bbs[b->pred(1)->_idx]; // Move up to predecessor block
261 }
262 if( b != this ) continue;
263 }
264
265 // Make sure this memory op is not already being used for a NullCheck
266 Node *e = mb->end();
267 if( e->is_MachNullCheck() && e->in(1) == mach )
268 continue; // Already being used as a NULL check
269
270 // Found a candidate! Pick one with least dom depth - the highest
271 // in the dom tree should be closest to the null check.
272 if( !best ||
273 cfg->_bbs[mach->_idx]->_dom_depth < cfg->_bbs[best->_idx]->_dom_depth ) {
274 best = mach;
275 bidx = vidx;
276
277 }
278 }
279 // No candidate!
280 if( !best ) return;
281
282 // ---- Found an implicit null check
283 extern int implicit_null_checks;
284 implicit_null_checks++;
285
286 if( is_decoden ) {
287 // Check if we need to hoist decodeHeapOop_not_null first.
288 Block *valb = cfg->_bbs[val->_idx];
289 if( this != valb && this->_dom_depth < valb->_dom_depth ) {
290 // Hoist it up to the end of the test block.
291 valb->find_remove(val);
292 this->add_inst(val);
293 cfg->_bbs.map(val->_idx,this);
294 // DecodeN on x86 may kill flags. Check for flag-killing projections
295 // that also need to be hoisted.
296 for (DUIterator_Fast jmax, j = val->fast_outs(jmax); j < jmax; j++) {
297 Node* n = val->fast_out(j);
298 if( n->Opcode() == Op_MachProj ) {
299 cfg->_bbs[n->_idx]->find_remove(n);
300 this->add_inst(n);
301 cfg->_bbs.map(n->_idx,this);
302 }
303 }
304 }
305 }
306 // Hoist the memory candidate up to the end of the test block.
307 Block *old_block = cfg->_bbs[best->_idx];
308 old_block->find_remove(best);
309 add_inst(best);
310 cfg->_bbs.map(best->_idx,this);
311
312 // Move the control dependence
313 if (best->in(0) && best->in(0) == old_block->_nodes[0])
314 best->set_req(0, _nodes[0]);
315
316 // Check for flag-killing projections that also need to be hoisted
317 // Should be DU safe because no edge updates.
318 for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) {
319 Node* n = best->fast_out(j);
320 if( n->Opcode() == Op_MachProj ) {
321 cfg->_bbs[n->_idx]->find_remove(n);
322 add_inst(n);
323 cfg->_bbs.map(n->_idx,this);
324 }
325 }
326
327 Compile *C = cfg->C;
328 // proj==Op_True --> ne test; proj==Op_False --> eq test.
329 // One of two graph shapes got matched:
330 // (IfTrue (If (Bool NE (CmpP ptr NULL))))
331 // (IfFalse (If (Bool EQ (CmpP ptr NULL))))
332 // NULL checks are always branch-if-eq. If we see a IfTrue projection
333 // then we are replacing a 'ne' test with a 'eq' NULL check test.
334 // We need to flip the projections to keep the same semantics.
335 if( proj->Opcode() == Op_IfTrue ) {
336 // Swap order of projections in basic block to swap branch targets
337 Node *tmp1 = _nodes[end_idx()+1];
338 Node *tmp2 = _nodes[end_idx()+2];
339 _nodes.map(end_idx()+1, tmp2);
340 _nodes.map(end_idx()+2, tmp1);
341 Node *tmp = new (C, 1) Node(C->top()); // Use not NULL input
342 tmp1->replace_by(tmp);
343 tmp2->replace_by(tmp1);
344 tmp->replace_by(tmp2);
345 tmp->destruct();
346 }
347
348 // Remove the existing null check; use a new implicit null check instead.
349 // Since schedule-local needs precise def-use info, we need to correct
350 // it as well.
351 Node *old_tst = proj->in(0);
352 MachNode *nul_chk = new (C) MachNullCheckNode(old_tst->in(0),best,bidx);
353 _nodes.map(end_idx(),nul_chk);
354 cfg->_bbs.map(nul_chk->_idx,this);
355 // Redirect users of old_test to nul_chk
356 for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2)
357 old_tst->last_out(i2)->set_req(0, nul_chk);
358 // Clean-up any dead code
359 for (uint i3 = 0; i3 < old_tst->req(); i3++)
360 old_tst->set_req(i3, NULL);
361
362 cfg->latency_from_uses(nul_chk);
363 cfg->latency_from_uses(best);
364 }
365
366
367 //------------------------------select-----------------------------------------
368 // Select a nice fellow from the worklist to schedule next. If there is only
369 // one choice, then use it. Projections take top priority for correctness
370 // reasons - if I see a projection, then it is next. There are a number of
371 // other special cases, for instructions that consume condition codes, et al.
372 // These are chosen immediately. Some instructions are required to immediately
373 // precede the last instruction in the block, and these are taken last. Of the
374 // remaining cases (most), choose the instruction with the greatest latency
375 // (that is, the most number of pseudo-cycles required to the end of the
376 // routine). If there is a tie, choose the instruction with the most inputs.
377 Node *Block::select(PhaseCFG *cfg, Node_List &worklist, int *ready_cnt, VectorSet &next_call, uint sched_slot) {
378
379 // If only a single entry on the stack, use it
380 uint cnt = worklist.size();
381 if (cnt == 1) {
382 Node *n = worklist[0];
383 worklist.map(0,worklist.pop());
384 return n;
385 }
386
387 uint choice = 0; // Bigger is most important
388 uint latency = 0; // Bigger is scheduled first
389 uint score = 0; // Bigger is better
390 int idx = -1; // Index in worklist
391
392 for( uint i=0; i<cnt; i++ ) { // Inspect entire worklist
393 // Order in worklist is used to break ties.
394 // See caller for how this is used to delay scheduling
395 // of induction variable increments to after the other
396 // uses of the phi are scheduled.
397 Node *n = worklist[i]; // Get Node on worklist
398
399 int iop = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : 0;
400 if( n->is_Proj() || // Projections always win
401 n->Opcode()== Op_Con || // So does constant 'Top'
402 iop == Op_CreateEx || // Create-exception must start block
403 iop == Op_CheckCastPP
404 ) {
405 worklist.map(i,worklist.pop());
406 return n;
407 }
408
409 // Final call in a block must be adjacent to 'catch'
410 Node *e = end();
411 if( e->is_Catch() && e->in(0)->in(0) == n )
412 continue;
413
414 // Memory op for an implicit null check has to be at the end of the block
415 if( e->is_MachNullCheck() && e->in(1) == n )
416 continue;
417
418 uint n_choice = 2;
419
420 // See if this instruction is consumed by a branch. If so, then (as the
421 // branch is the last instruction in the basic block) force it to the
422 // end of the basic block
423 if ( must_clone[iop] ) {
424 // See if any use is a branch
425 bool found_machif = false;
426
427 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
428 Node* use = n->fast_out(j);
429
430 // The use is a conditional branch, make them adjacent
431 if (use->is_MachIf() && cfg->_bbs[use->_idx]==this ) {
432 found_machif = true;
433 break;
434 }
435
436 // More than this instruction pending for successor to be ready,
437 // don't choose this if other opportunities are ready
438 if (ready_cnt[use->_idx] > 1)
439 n_choice = 1;
440 }
441
442 // loop terminated, prefer not to use this instruction
443 if (found_machif)
444 continue;
445 }
446
447 // See if this has a predecessor that is "must_clone", i.e. sets the
448 // condition code. If so, choose this first
449 for (uint j = 0; j < n->req() ; j++) {
450 Node *inn = n->in(j);
451 if (inn) {
452 if (inn->is_Mach() && must_clone[inn->as_Mach()->ideal_Opcode()] ) {
453 n_choice = 3;
454 break;
455 }
456 }
457 }
458
459 // MachTemps should be scheduled last so they are near their uses
460 if (n->is_MachTemp()) {
461 n_choice = 1;
462 }
463
464 uint n_latency = cfg->_node_latency.at_grow(n->_idx);
465 uint n_score = n->req(); // Many inputs get high score to break ties
466
467 // Keep best latency found
468 if( choice < n_choice ||
469 ( choice == n_choice &&
470 ( latency < n_latency ||
471 ( latency == n_latency &&
472 ( score < n_score ))))) {
473 choice = n_choice;
474 latency = n_latency;
475 score = n_score;
476 idx = i; // Also keep index in worklist
477 }
478 } // End of for all ready nodes in worklist
479
480 assert(idx >= 0, "index should be set");
481 Node *n = worklist[(uint)idx]; // Get the winner
482
483 worklist.map((uint)idx, worklist.pop()); // Compress worklist
484 return n;
485 }
486
487
488 //------------------------------set_next_call----------------------------------
489 void Block::set_next_call( Node *n, VectorSet &next_call, Block_Array &bbs ) {
490 if( next_call.test_set(n->_idx) ) return;
491 for( uint i=0; i<n->len(); i++ ) {
492 Node *m = n->in(i);
493 if( !m ) continue; // must see all nodes in block that precede call
494 if( bbs[m->_idx] == this )
495 set_next_call( m, next_call, bbs );
496 }
497 }
498
499 //------------------------------needed_for_next_call---------------------------
500 // Set the flag 'next_call' for each Node that is needed for the next call to
501 // be scheduled. This flag lets me bias scheduling so Nodes needed for the
502 // next subroutine call get priority - basically it moves things NOT needed
503 // for the next call till after the call. This prevents me from trying to
504 // carry lots of stuff live across a call.
505 void Block::needed_for_next_call(Node *this_call, VectorSet &next_call, Block_Array &bbs) {
506 // Find the next control-defining Node in this block
507 Node* call = NULL;
508 for (DUIterator_Fast imax, i = this_call->fast_outs(imax); i < imax; i++) {
509 Node* m = this_call->fast_out(i);
510 if( bbs[m->_idx] == this && // Local-block user
511 m != this_call && // Not self-start node
512 m->is_Call() )
513 call = m;
514 break;
515 }
516 if (call == NULL) return; // No next call (e.g., block end is near)
517 // Set next-call for all inputs to this call
518 set_next_call(call, next_call, bbs);
519 }
520
521 //------------------------------sched_call-------------------------------------
522 uint Block::sched_call( Matcher &matcher, Block_Array &bbs, uint node_cnt, Node_List &worklist, int *ready_cnt, MachCallNode *mcall, VectorSet &next_call ) {
523 RegMask regs;
524
525 // Schedule all the users of the call right now. All the users are
526 // projection Nodes, so they must be scheduled next to the call.
527 // Collect all the defined registers.
528 for (DUIterator_Fast imax, i = mcall->fast_outs(imax); i < imax; i++) {
529 Node* n = mcall->fast_out(i);
530 assert( n->Opcode()==Op_MachProj, "" );
531 --ready_cnt[n->_idx];
532 assert( !ready_cnt[n->_idx], "" );
533 // Schedule next to call
534 _nodes.map(node_cnt++, n);
535 // Collect defined registers
536 regs.OR(n->out_RegMask());
537 // Check for scheduling the next control-definer
538 if( n->bottom_type() == Type::CONTROL )
539 // Warm up next pile of heuristic bits
540 needed_for_next_call(n, next_call, bbs);
541
542 // Children of projections are now all ready
543 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
544 Node* m = n->fast_out(j); // Get user
545 if( bbs[m->_idx] != this ) continue;
546 if( m->is_Phi() ) continue;
547 if( !--ready_cnt[m->_idx] )
548 worklist.push(m);
549 }
550
551 }
552
553 // Act as if the call defines the Frame Pointer.
554 // Certainly the FP is alive and well after the call.
555 regs.Insert(matcher.c_frame_pointer());
556
557 // Set all registers killed and not already defined by the call.
558 uint r_cnt = mcall->tf()->range()->cnt();
559 int op = mcall->ideal_Opcode();
560 MachProjNode *proj = new (matcher.C, 1) MachProjNode( mcall, r_cnt+1, RegMask::Empty, MachProjNode::fat_proj );
561 bbs.map(proj->_idx,this);
562 _nodes.insert(node_cnt++, proj);
563
564 // Select the right register save policy.
565 const char * save_policy;
566 switch (op) {
567 case Op_CallRuntime:
568 case Op_CallLeaf:
569 case Op_CallLeafNoFP:
570 // Calling C code so use C calling convention
571 save_policy = matcher._c_reg_save_policy;
572 break;
573
574 case Op_CallStaticJava:
575 case Op_CallDynamicJava:
576 // Calling Java code so use Java calling convention
577 save_policy = matcher._register_save_policy;
578 break;
579
580 default:
581 ShouldNotReachHere();
582 }
583
584 // When using CallRuntime mark SOE registers as killed by the call
585 // so values that could show up in the RegisterMap aren't live in a
586 // callee saved register since the register wouldn't know where to
587 // find them. CallLeaf and CallLeafNoFP are ok because they can't
588 // have debug info on them. Strictly speaking this only needs to be
589 // done for oops since idealreg2debugmask takes care of debug info
590 // references but there no way to handle oops differently than other
591 // pointers as far as the kill mask goes.
592 bool exclude_soe = op == Op_CallRuntime;
593
594 // If the call is a MethodHandle invoke, we need to exclude the
595 // register which is used to save the SP value over MH invokes from
596 // the mask. Otherwise this register could be used for
597 // deoptimization information.
598 if (op == Op_CallStaticJava) {
599 MachCallStaticJavaNode* mcallstaticjava = (MachCallStaticJavaNode*) mcall;
600 if (mcallstaticjava->_method_handle_invoke)
601 proj->_rout.OR(Matcher::method_handle_invoke_SP_save_mask());
602 }
603
604 // Fill in the kill mask for the call
605 for( OptoReg::Name r = OptoReg::Name(0); r < _last_Mach_Reg; r=OptoReg::add(r,1) ) {
606 if( !regs.Member(r) ) { // Not already defined by the call
607 // Save-on-call register?
608 if ((save_policy[r] == 'C') ||
609 (save_policy[r] == 'A') ||
610 ((save_policy[r] == 'E') && exclude_soe)) {
611 proj->_rout.Insert(r);
612 }
613 }
614 }
615
616 return node_cnt;
617 }
618
619
620 //------------------------------schedule_local---------------------------------
621 // Topological sort within a block. Someday become a real scheduler.
622 bool Block::schedule_local(PhaseCFG *cfg, Matcher &matcher, int *ready_cnt, VectorSet &next_call) {
623 // Already "sorted" are the block start Node (as the first entry), and
624 // the block-ending Node and any trailing control projections. We leave
625 // these alone. PhiNodes and ParmNodes are made to follow the block start
626 // Node. Everything else gets topo-sorted.
627
628 #ifndef PRODUCT
629 if (cfg->trace_opto_pipelining()) {
630 tty->print_cr("# --- schedule_local B%d, before: ---", _pre_order);
631 for (uint i = 0;i < _nodes.size();i++) {
632 tty->print("# ");
633 _nodes[i]->fast_dump();
634 }
635 tty->print_cr("#");
636 }
637 #endif
638
639 // RootNode is already sorted
640 if( _nodes.size() == 1 ) return true;
641
642 // Move PhiNodes and ParmNodes from 1 to cnt up to the start
643 uint node_cnt = end_idx();
644 uint phi_cnt = 1;
645 uint i;
646 for( i = 1; i<node_cnt; i++ ) { // Scan for Phi
647 Node *n = _nodes[i];
648 if( n->is_Phi() || // Found a PhiNode or ParmNode
649 (n->is_Proj() && n->in(0) == head()) ) {
650 // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt
651 _nodes.map(i,_nodes[phi_cnt]);
652 _nodes.map(phi_cnt++,n); // swap Phi/Parm up front
653 } else { // All others
654 // Count block-local inputs to 'n'
655 uint cnt = n->len(); // Input count
656 uint local = 0;
657 for( uint j=0; j<cnt; j++ ) {
658 Node *m = n->in(j);
659 if( m && cfg->_bbs[m->_idx] == this && !m->is_top() )
660 local++; // One more block-local input
661 }
662 ready_cnt[n->_idx] = local; // Count em up
663
664 // A few node types require changing a required edge to a precedence edge
665 // before allocation.
666 if( UseConcMarkSweepGC || UseG1GC ) {
667 if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_StoreCM ) {
668 // Note: Required edges with an index greater than oper_input_base
669 // are not supported by the allocator.
670 // Note2: Can only depend on unmatched edge being last,
671 // can not depend on its absolute position.
672 Node *oop_store = n->in(n->req() - 1);
673 n->del_req(n->req() - 1);
674 n->add_prec(oop_store);
675 assert(cfg->_bbs[oop_store->_idx]->_dom_depth <= this->_dom_depth, "oop_store must dominate card-mark");
676 }
677 }
678 if( n->is_Mach() && n->req() > TypeFunc::Parms &&
679 (n->as_Mach()->ideal_Opcode() == Op_MemBarAcquire ||
680 n->as_Mach()->ideal_Opcode() == Op_MemBarVolatile) ) {
681 // MemBarAcquire could be created without Precedent edge.
682 // del_req() replaces the specified edge with the last input edge
683 // and then removes the last edge. If the specified edge > number of
684 // edges the last edge will be moved outside of the input edges array
685 // and the edge will be lost. This is why this code should be
686 // executed only when Precedent (== TypeFunc::Parms) edge is present.
687 Node *x = n->in(TypeFunc::Parms);
688 n->del_req(TypeFunc::Parms);
689 n->add_prec(x);
690 }
691 }
692 }
693 for(uint i2=i; i2<_nodes.size(); i2++ ) // Trailing guys get zapped count
694 ready_cnt[_nodes[i2]->_idx] = 0;
695
696 // All the prescheduled guys do not hold back internal nodes
697 uint i3;
698 for(i3 = 0; i3<phi_cnt; i3++ ) { // For all pre-scheduled
699 Node *n = _nodes[i3]; // Get pre-scheduled
700 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
701 Node* m = n->fast_out(j);
702 if( cfg->_bbs[m->_idx] ==this ) // Local-block user
703 ready_cnt[m->_idx]--; // Fix ready count
704 }
705 }
706
707 Node_List delay;
708 // Make a worklist
709 Node_List worklist;
710 for(uint i4=i3; i4<node_cnt; i4++ ) { // Put ready guys on worklist
711 Node *m = _nodes[i4];
712 if( !ready_cnt[m->_idx] ) { // Zero ready count?
713 if (m->is_iteratively_computed()) {
714 // Push induction variable increments last to allow other uses
715 // of the phi to be scheduled first. The select() method breaks
716 // ties in scheduling by worklist order.
717 delay.push(m);
718 } else if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CreateEx) {
719 // Force the CreateEx to the top of the list so it's processed
720 // first and ends up at the start of the block.
721 worklist.insert(0, m);
722 } else {
723 worklist.push(m); // Then on to worklist!
724 }
725 }
726 }
727 while (delay.size()) {
728 Node* d = delay.pop();
729 worklist.push(d);
730 }
731
732 // Warm up the 'next_call' heuristic bits
733 needed_for_next_call(_nodes[0], next_call, cfg->_bbs);
734
735 #ifndef PRODUCT
736 if (cfg->trace_opto_pipelining()) {
737 for (uint j=0; j<_nodes.size(); j++) {
738 Node *n = _nodes[j];
739 int idx = n->_idx;
740 tty->print("# ready cnt:%3d ", ready_cnt[idx]);
741 tty->print("latency:%3d ", cfg->_node_latency.at_grow(idx));
742 tty->print("%4d: %s\n", idx, n->Name());
743 }
744 }
745 #endif
746
747 // Pull from worklist and schedule
748 while( worklist.size() ) { // Worklist is not ready
749
750 #ifndef PRODUCT
751 if (cfg->trace_opto_pipelining()) {
752 tty->print("# ready list:");
753 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
754 Node *n = worklist[i]; // Get Node on worklist
755 tty->print(" %d", n->_idx);
756 }
757 tty->cr();
758 }
759 #endif
760
761 // Select and pop a ready guy from worklist
762 Node* n = select(cfg, worklist, ready_cnt, next_call, phi_cnt);
763 _nodes.map(phi_cnt++,n); // Schedule him next
764
765 #ifndef PRODUCT
766 if (cfg->trace_opto_pipelining()) {
767 tty->print("# select %d: %s", n->_idx, n->Name());
768 tty->print(", latency:%d", cfg->_node_latency.at_grow(n->_idx));
769 n->dump();
770 if (Verbose) {
771 tty->print("# ready list:");
772 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
773 Node *n = worklist[i]; // Get Node on worklist
774 tty->print(" %d", n->_idx);
775 }
776 tty->cr();
777 }
778 }
779
780 #endif
781 if( n->is_MachCall() ) {
782 MachCallNode *mcall = n->as_MachCall();
783 phi_cnt = sched_call(matcher, cfg->_bbs, phi_cnt, worklist, ready_cnt, mcall, next_call);
784 continue;
785 }
786 // Children are now all ready
787 for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) {
788 Node* m = n->fast_out(i5); // Get user
789 if( cfg->_bbs[m->_idx] != this ) continue;
790 if( m->is_Phi() ) continue;
791 if( !--ready_cnt[m->_idx] )
792 worklist.push(m);
793 }
794 }
795
796 if( phi_cnt != end_idx() ) {
797 // did not schedule all. Retry, Bailout, or Die
798 Compile* C = matcher.C;
799 if (C->subsume_loads() == true && !C->failing()) {
800 // Retry with subsume_loads == false
801 // If this is the first failure, the sentinel string will "stick"
802 // to the Compile object, and the C2Compiler will see it and retry.
803 C->record_failure(C2Compiler::retry_no_subsuming_loads());
804 }
805 // assert( phi_cnt == end_idx(), "did not schedule all" );
806 return false;
807 }
808
809 #ifndef PRODUCT
810 if (cfg->trace_opto_pipelining()) {
811 tty->print_cr("#");
812 tty->print_cr("# after schedule_local");
813 for (uint i = 0;i < _nodes.size();i++) {
814 tty->print("# ");
815 _nodes[i]->fast_dump();
816 }
817 tty->cr();
818 }
819 #endif
820
821
822 return true;
823 }
824
825 //--------------------------catch_cleanup_fix_all_inputs-----------------------
826 static void catch_cleanup_fix_all_inputs(Node *use, Node *old_def, Node *new_def) {
827 for (uint l = 0; l < use->len(); l++) {
828 if (use->in(l) == old_def) {
829 if (l < use->req()) {
830 use->set_req(l, new_def);
831 } else {
832 use->rm_prec(l);
833 use->add_prec(new_def);
834 l--;
835 }
836 }
837 }
838 }
839
840 //------------------------------catch_cleanup_find_cloned_def------------------
841 static Node *catch_cleanup_find_cloned_def(Block *use_blk, Node *def, Block *def_blk, Block_Array &bbs, int n_clone_idx) {
842 assert( use_blk != def_blk, "Inter-block cleanup only");
843
844 // The use is some block below the Catch. Find and return the clone of the def
845 // that dominates the use. If there is no clone in a dominating block, then
846 // create a phi for the def in a dominating block.
847
848 // Find which successor block dominates this use. The successor
849 // blocks must all be single-entry (from the Catch only; I will have
850 // split blocks to make this so), hence they all dominate.
851 while( use_blk->_dom_depth > def_blk->_dom_depth+1 )
852 use_blk = use_blk->_idom;
853
854 // Find the successor
855 Node *fixup = NULL;
856
857 uint j;
858 for( j = 0; j < def_blk->_num_succs; j++ )
859 if( use_blk == def_blk->_succs[j] )
860 break;
861
862 if( j == def_blk->_num_succs ) {
863 // Block at same level in dom-tree is not a successor. It needs a
864 // PhiNode, the PhiNode uses from the def and IT's uses need fixup.
865 Node_Array inputs = new Node_List(Thread::current()->resource_area());
866 for(uint k = 1; k < use_blk->num_preds(); k++) {
867 inputs.map(k, catch_cleanup_find_cloned_def(bbs[use_blk->pred(k)->_idx], def, def_blk, bbs, n_clone_idx));
868 }
869
870 // Check to see if the use_blk already has an identical phi inserted.
871 // If it exists, it will be at the first position since all uses of a
872 // def are processed together.
873 Node *phi = use_blk->_nodes[1];
874 if( phi->is_Phi() ) {
875 fixup = phi;
876 for (uint k = 1; k < use_blk->num_preds(); k++) {
877 if (phi->in(k) != inputs[k]) {
878 // Not a match
879 fixup = NULL;
880 break;
881 }
882 }
883 }
884
885 // If an existing PhiNode was not found, make a new one.
886 if (fixup == NULL) {
887 Node *new_phi = PhiNode::make(use_blk->head(), def);
888 use_blk->_nodes.insert(1, new_phi);
889 bbs.map(new_phi->_idx, use_blk);
890 for (uint k = 1; k < use_blk->num_preds(); k++) {
891 new_phi->set_req(k, inputs[k]);
892 }
893 fixup = new_phi;
894 }
895
896 } else {
897 // Found the use just below the Catch. Make it use the clone.
898 fixup = use_blk->_nodes[n_clone_idx];
899 }
900
901 return fixup;
902 }
903
904 //--------------------------catch_cleanup_intra_block--------------------------
905 // Fix all input edges in use that reference "def". The use is in the same
906 // block as the def and both have been cloned in each successor block.
907 static void catch_cleanup_intra_block(Node *use, Node *def, Block *blk, int beg, int n_clone_idx) {
908
909 // Both the use and def have been cloned. For each successor block,
910 // get the clone of the use, and make its input the clone of the def
911 // found in that block.
912
913 uint use_idx = blk->find_node(use);
914 uint offset_idx = use_idx - beg;
915 for( uint k = 0; k < blk->_num_succs; k++ ) {
916 // Get clone in each successor block
917 Block *sb = blk->_succs[k];
918 Node *clone = sb->_nodes[offset_idx+1];
919 assert( clone->Opcode() == use->Opcode(), "" );
920
921 // Make use-clone reference the def-clone
922 catch_cleanup_fix_all_inputs(clone, def, sb->_nodes[n_clone_idx]);
923 }
924 }
925
926 //------------------------------catch_cleanup_inter_block---------------------
927 // Fix all input edges in use that reference "def". The use is in a different
928 // block than the def.
929 static void catch_cleanup_inter_block(Node *use, Block *use_blk, Node *def, Block *def_blk, Block_Array &bbs, int n_clone_idx) {
930 if( !use_blk ) return; // Can happen if the use is a precedence edge
931
932 Node *new_def = catch_cleanup_find_cloned_def(use_blk, def, def_blk, bbs, n_clone_idx);
933 catch_cleanup_fix_all_inputs(use, def, new_def);
934 }
935
936 //------------------------------call_catch_cleanup-----------------------------
937 // If we inserted any instructions between a Call and his CatchNode,
938 // clone the instructions on all paths below the Catch.
939 void Block::call_catch_cleanup(Block_Array &bbs) {
940
941 // End of region to clone
942 uint end = end_idx();
943 if( !_nodes[end]->is_Catch() ) return;
944 // Start of region to clone
945 uint beg = end;
946 while( _nodes[beg-1]->Opcode() != Op_MachProj ||
947 !_nodes[beg-1]->in(0)->is_Call() ) {
948 beg--;
949 assert(beg > 0,"Catch cleanup walking beyond block boundary");
950 }
951 // Range of inserted instructions is [beg, end)
952 if( beg == end ) return;
953
954 // Clone along all Catch output paths. Clone area between the 'beg' and
955 // 'end' indices.
956 for( uint i = 0; i < _num_succs; i++ ) {
957 Block *sb = _succs[i];
958 // Clone the entire area; ignoring the edge fixup for now.
959 for( uint j = end; j > beg; j-- ) {
960 Node *clone = _nodes[j-1]->clone();
961 sb->_nodes.insert( 1, clone );
962 bbs.map(clone->_idx,sb);
963 }
964 }
965
966
967 // Fixup edges. Check the def-use info per cloned Node
968 for(uint i2 = beg; i2 < end; i2++ ) {
969 uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block
970 Node *n = _nodes[i2]; // Node that got cloned
971 // Need DU safe iterator because of edge manipulation in calls.
972 Unique_Node_List *out = new Unique_Node_List(Thread::current()->resource_area());
973 for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) {
974 out->push(n->fast_out(j1));
975 }
976 uint max = out->size();
977 for (uint j = 0; j < max; j++) {// For all users
978 Node *use = out->pop();
979 Block *buse = bbs[use->_idx];
980 if( use->is_Phi() ) {
981 for( uint k = 1; k < use->req(); k++ )
982 if( use->in(k) == n ) {
983 Node *fixup = catch_cleanup_find_cloned_def(bbs[buse->pred(k)->_idx], n, this, bbs, n_clone_idx);
984 use->set_req(k, fixup);
985 }
986 } else {
987 if (this == buse) {
988 catch_cleanup_intra_block(use, n, this, beg, n_clone_idx);
989 } else {
990 catch_cleanup_inter_block(use, buse, n, this, bbs, n_clone_idx);
991 }
992 }
993 } // End for all users
994
995 } // End of for all Nodes in cloned area
996
997 // Remove the now-dead cloned ops
998 for(uint i3 = beg; i3 < end; i3++ ) {
999 _nodes[beg]->disconnect_inputs(NULL);
1000 _nodes.remove(beg);
1001 }
1002
1003 // If the successor blocks have a CreateEx node, move it back to the top
1004 for(uint i4 = 0; i4 < _num_succs; i4++ ) {
1005 Block *sb = _succs[i4];
1006 uint new_cnt = end - beg;
1007 // Remove any newly created, but dead, nodes.
1008 for( uint j = new_cnt; j > 0; j-- ) {
1009 Node *n = sb->_nodes[j];
1010 if (n->outcnt() == 0 &&
1011 (!n->is_Proj() || n->as_Proj()->in(0)->outcnt() == 1) ){
1012 n->disconnect_inputs(NULL);
1013 sb->_nodes.remove(j);
1014 new_cnt--;
1015 }
1016 }
1017 // If any newly created nodes remain, move the CreateEx node to the top
1018 if (new_cnt > 0) {
1019 Node *cex = sb->_nodes[1+new_cnt];
1020 if( cex->is_Mach() && cex->as_Mach()->ideal_Opcode() == Op_CreateEx ) {
1021 sb->_nodes.remove(1+new_cnt);
1022 sb->_nodes.insert(1,cex);
1023 }
1024 }
1025 }
1026 }