1 /*
2 * Copyright 1998-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
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.
36 void Block::implicit_null_check(PhaseCFG *cfg, Node *proj, Node *val, int allowed_reasons) {
37 // Assume if null check need for 0 offset then always needed
38 // Intel solaris doesn't support any null checks yet and no
39 // mechanism exists (yet) to set the switches at an os_cpu level
40 if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return;
41
42 // Make sure the ptr-is-null path appears to be uncommon!
43 float f = end()->as_MachIf()->_prob;
44 if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f;
45 if( f > PROB_UNLIKELY_MAG(4) ) return;
46
47 uint bidx = 0; // Capture index of value into memop
48 bool was_store; // Memory op is a store op
49
50 // Get the successor block for if the test ptr is non-null
51 Block* not_null_block; // this one goes with the proj
52 Block* null_block;
53 if (_nodes[_nodes.size()-1] == proj) {
54 null_block = _succs[0];
55 not_null_block = _succs[1];
56 } else {
57 assert(_nodes[_nodes.size()-2] == proj, "proj is one or the other");
58 not_null_block = _succs[0];
59 null_block = _succs[1];
60 }
61 while (null_block->is_Empty() == Block::empty_with_goto) {
62 null_block = null_block->_succs[0];
63 }
64
65 // Search the exception block for an uncommon trap.
66 // (See Parse::do_if and Parse::do_ifnull for the reason
67 // we need an uncommon trap. Briefly, we need a way to
68 // detect failure of this optimization, as in 6366351.)
69 {
70 bool found_trap = false;
71 for (uint i1 = 0; i1 < null_block->_nodes.size(); i1++) {
72 Node* nn = null_block->_nodes[i1];
73 if (nn->is_MachCall() &&
74 nn->as_MachCall()->entry_point() ==
75 SharedRuntime::uncommon_trap_blob()->instructions_begin()) {
76 const Type* trtype = nn->in(TypeFunc::Parms)->bottom_type();
77 if (trtype->isa_int() && trtype->is_int()->is_con()) {
78 jint tr_con = trtype->is_int()->get_con();
79 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(tr_con);
80 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(tr_con);
81 assert((int)reason < (int)BitsPerInt, "recode bit map");
82 if (is_set_nth_bit(allowed_reasons, (int) reason)
83 && action != Deoptimization::Action_none) {
84 // This uncommon trap is sure to recompile, eventually.
85 // When that happens, C->too_many_traps will prevent
86 // this transformation from happening again.
87 found_trap = true;
88 }
89 }
90 break;
91 }
92 }
93 if (!found_trap) {
94 // We did not find an uncommon trap.
95 return;
96 }
97 }
98
99 // Search the successor block for a load or store who's base value is also
100 // the tested value. There may be several.
101 Node_List *out = new Node_List(Thread::current()->resource_area());
102 MachNode *best = NULL; // Best found so far
103 for (DUIterator i = val->outs(); val->has_out(i); i++) {
104 Node *m = val->out(i);
105 if( !m->is_Mach() ) continue;
106 MachNode *mach = m->as_Mach();
107 was_store = false;
108 switch( mach->ideal_Opcode() ) {
109 case Op_LoadB:
110 case Op_LoadUS:
111 case Op_LoadD:
112 case Op_LoadF:
113 case Op_LoadI:
114 case Op_LoadL:
115 case Op_LoadP:
116 case Op_LoadN:
117 case Op_LoadS:
118 case Op_LoadKlass:
119 case Op_LoadNKlass:
120 case Op_LoadRange:
121 case Op_LoadD_unaligned:
122 case Op_LoadL_unaligned:
123 break;
124 case Op_StoreB:
125 case Op_StoreC:
126 case Op_StoreCM:
127 case Op_StoreD:
128 case Op_StoreF:
129 case Op_StoreI:
130 case Op_StoreL:
131 case Op_StoreP:
132 case Op_StoreN:
133 was_store = true; // Memory op is a store op
134 // Stores will have their address in slot 2 (memory in slot 1).
135 // If the value being nul-checked is in another slot, it means we
136 // are storing the checked value, which does NOT check the value!
137 if( mach->in(2) != val ) continue;
138 break; // Found a memory op?
139 case Op_StrComp:
140 case Op_StrEquals:
141 case Op_StrIndexOf:
142 case Op_AryEq:
143 // Not a legit memory op for implicit null check regardless of
144 // embedded loads
145 continue;
146 default: // Also check for embedded loads
147 if( !mach->needs_anti_dependence_check() )
148 continue; // Not an memory op; skip it
149 break;
150 }
151 // check if the offset is not too high for implicit exception
152 {
153 intptr_t offset = 0;
154 const TypePtr *adr_type = NULL; // Do not need this return value here
155 const Node* base = mach->get_base_and_disp(offset, adr_type);
156 if (base == NULL || base == NodeSentinel) {
157 // Narrow oop address doesn't have base, only index
158 if( val->bottom_type()->isa_narrowoop() &&
159 MacroAssembler::needs_explicit_null_check(offset) )
160 continue; // Give up if offset is beyond page size
161 // cannot reason about it; is probably not implicit null exception
162 } else {
163 const TypePtr* tptr;
164 if (UseCompressedOops && Universe::narrow_oop_shift() == 0) {
165 // 32-bits narrow oop can be the base of address expressions
166 tptr = base->bottom_type()->make_ptr();
167 } else {
168 // only regular oops are expected here
169 tptr = base->bottom_type()->is_ptr();
170 }
171 // Give up if offset is not a compile-time constant
172 if( offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot )
173 continue;
174 offset += tptr->_offset; // correct if base is offseted
175 if( MacroAssembler::needs_explicit_null_check(offset) )
176 continue; // Give up is reference is beyond 4K page size
177 }
178 }
179
180 // Check ctrl input to see if the null-check dominates the memory op
181 Block *cb = cfg->_bbs[mach->_idx];
182 cb = cb->_idom; // Always hoist at least 1 block
183 if( !was_store ) { // Stores can be hoisted only one block
184 while( cb->_dom_depth > (_dom_depth + 1))
185 cb = cb->_idom; // Hoist loads as far as we want
186 // The non-null-block should dominate the memory op, too. Live
187 // range spilling will insert a spill in the non-null-block if it is
188 // needs to spill the memory op for an implicit null check.
189 if (cb->_dom_depth == (_dom_depth + 1)) {
190 if (cb != not_null_block) continue;
191 cb = cb->_idom;
192 }
193 }
194 if( cb != this ) continue;
195
196 // Found a memory user; see if it can be hoisted to check-block
197 uint vidx = 0; // Capture index of value into memop
198 uint j;
199 for( j = mach->req()-1; j > 0; j-- ) {
200 if( mach->in(j) == val ) vidx = j;
201 // Block of memory-op input
202 Block *inb = cfg->_bbs[mach->in(j)->_idx];
203 Block *b = this; // Start from nul check
204 while( b != inb && b->_dom_depth > inb->_dom_depth )
205 b = b->_idom; // search upwards for input
206 // See if input dominates null check
207 if( b != inb )
208 break;
209 }
210 if( j > 0 )
211 continue;
212 Block *mb = cfg->_bbs[mach->_idx];
213 // Hoisting stores requires more checks for the anti-dependence case.
214 // Give up hoisting if we have to move the store past any load.
215 if( was_store ) {
216 Block *b = mb; // Start searching here for a local load
217 // mach use (faulting) trying to hoist
218 // n might be blocker to hoisting
219 while( b != this ) {
220 uint k;
221 for( k = 1; k < b->_nodes.size(); k++ ) {
222 Node *n = b->_nodes[k];
223 if( n->needs_anti_dependence_check() &&
224 n->in(LoadNode::Memory) == mach->in(StoreNode::Memory) )
225 break; // Found anti-dependent load
226 }
227 if( k < b->_nodes.size() )
228 break; // Found anti-dependent load
229 // Make sure control does not do a merge (would have to check allpaths)
230 if( b->num_preds() != 2 ) break;
231 b = cfg->_bbs[b->pred(1)->_idx]; // Move up to predecessor block
232 }
233 if( b != this ) continue;
234 }
235
236 // Make sure this memory op is not already being used for a NullCheck
237 Node *e = mb->end();
238 if( e->is_MachNullCheck() && e->in(1) == mach )
239 continue; // Already being used as a NULL check
240
241 // Found a candidate! Pick one with least dom depth - the highest
242 // in the dom tree should be closest to the null check.
243 if( !best ||
244 cfg->_bbs[mach->_idx]->_dom_depth < cfg->_bbs[best->_idx]->_dom_depth ) {
245 best = mach;
246 bidx = vidx;
247
248 }
249 }
250 // No candidate!
251 if( !best ) return;
252
253 // ---- Found an implicit null check
254 extern int implicit_null_checks;
255 implicit_null_checks++;
256
257 // Hoist the memory candidate up to the end of the test block.
258 Block *old_block = cfg->_bbs[best->_idx];
259 old_block->find_remove(best);
260 add_inst(best);
261 cfg->_bbs.map(best->_idx,this);
262
263 // Move the control dependence
264 if (best->in(0) && best->in(0) == old_block->_nodes[0])
265 best->set_req(0, _nodes[0]);
266
267 // Check for flag-killing projections that also need to be hoisted
268 // Should be DU safe because no edge updates.
269 for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) {
270 Node* n = best->fast_out(j);
271 if( n->Opcode() == Op_MachProj ) {
272 cfg->_bbs[n->_idx]->find_remove(n);
273 add_inst(n);
274 cfg->_bbs.map(n->_idx,this);
275 }
276 }
277
278 Compile *C = cfg->C;
279 // proj==Op_True --> ne test; proj==Op_False --> eq test.
280 // One of two graph shapes got matched:
281 // (IfTrue (If (Bool NE (CmpP ptr NULL))))
282 // (IfFalse (If (Bool EQ (CmpP ptr NULL))))
283 // NULL checks are always branch-if-eq. If we see a IfTrue projection
284 // then we are replacing a 'ne' test with a 'eq' NULL check test.
285 // We need to flip the projections to keep the same semantics.
286 if( proj->Opcode() == Op_IfTrue ) {
287 // Swap order of projections in basic block to swap branch targets
288 Node *tmp1 = _nodes[end_idx()+1];
289 Node *tmp2 = _nodes[end_idx()+2];
290 _nodes.map(end_idx()+1, tmp2);
291 _nodes.map(end_idx()+2, tmp1);
292 Node *tmp = new (C, 1) Node(C->top()); // Use not NULL input
293 tmp1->replace_by(tmp);
294 tmp2->replace_by(tmp1);
295 tmp->replace_by(tmp2);
296 tmp->destruct();
297 }
298
299 // Remove the existing null check; use a new implicit null check instead.
300 // Since schedule-local needs precise def-use info, we need to correct
301 // it as well.
302 Node *old_tst = proj->in(0);
303 MachNode *nul_chk = new (C) MachNullCheckNode(old_tst->in(0),best,bidx);
304 _nodes.map(end_idx(),nul_chk);
305 cfg->_bbs.map(nul_chk->_idx,this);
306 // Redirect users of old_test to nul_chk
307 for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2)
308 old_tst->last_out(i2)->set_req(0, nul_chk);
309 // Clean-up any dead code
310 for (uint i3 = 0; i3 < old_tst->req(); i3++)
311 old_tst->set_req(i3, NULL);
312
313 cfg->latency_from_uses(nul_chk);
314 cfg->latency_from_uses(best);
315 }
316
317
318 //------------------------------select-----------------------------------------
319 // Select a nice fellow from the worklist to schedule next. If there is only
320 // one choice, then use it. Projections take top priority for correctness
321 // reasons - if I see a projection, then it is next. There are a number of
322 // other special cases, for instructions that consume condition codes, et al.
323 // These are chosen immediately. Some instructions are required to immediately
324 // precede the last instruction in the block, and these are taken last. Of the
325 // remaining cases (most), choose the instruction with the greatest latency
326 // (that is, the most number of pseudo-cycles required to the end of the
327 // routine). If there is a tie, choose the instruction with the most inputs.
328 Node *Block::select(PhaseCFG *cfg, Node_List &worklist, int *ready_cnt, VectorSet &next_call, uint sched_slot) {
329
330 // If only a single entry on the stack, use it
331 uint cnt = worklist.size();
332 if (cnt == 1) {
333 Node *n = worklist[0];
334 worklist.map(0,worklist.pop());
335 return n;
336 }
337
338 uint choice = 0; // Bigger is most important
339 uint latency = 0; // Bigger is scheduled first
340 uint score = 0; // Bigger is better
341 int idx = -1; // Index in worklist
342
343 for( uint i=0; i<cnt; i++ ) { // Inspect entire worklist
344 // Order in worklist is used to break ties.
345 // See caller for how this is used to delay scheduling
346 // of induction variable increments to after the other
347 // uses of the phi are scheduled.
348 Node *n = worklist[i]; // Get Node on worklist
349
350 int iop = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : 0;
351 if( n->is_Proj() || // Projections always win
352 n->Opcode()== Op_Con || // So does constant 'Top'
353 iop == Op_CreateEx || // Create-exception must start block
354 iop == Op_CheckCastPP
355 ) {
356 worklist.map(i,worklist.pop());
357 return n;
358 }
359
360 // Final call in a block must be adjacent to 'catch'
361 Node *e = end();
362 if( e->is_Catch() && e->in(0)->in(0) == n )
363 continue;
364
365 // Memory op for an implicit null check has to be at the end of the block
366 if( e->is_MachNullCheck() && e->in(1) == n )
367 continue;
368
369 uint n_choice = 2;
370
371 // See if this instruction is consumed by a branch. If so, then (as the
372 // branch is the last instruction in the basic block) force it to the
373 // end of the basic block
374 if ( must_clone[iop] ) {
375 // See if any use is a branch
376 bool found_machif = false;
377
378 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
379 Node* use = n->fast_out(j);
380
381 // The use is a conditional branch, make them adjacent
382 if (use->is_MachIf() && cfg->_bbs[use->_idx]==this ) {
383 found_machif = true;
384 break;
385 }
386
387 // More than this instruction pending for successor to be ready,
388 // don't choose this if other opportunities are ready
389 if (ready_cnt[use->_idx] > 1)
390 n_choice = 1;
391 }
392
393 // loop terminated, prefer not to use this instruction
394 if (found_machif)
395 continue;
396 }
397
398 // See if this has a predecessor that is "must_clone", i.e. sets the
399 // condition code. If so, choose this first
400 for (uint j = 0; j < n->req() ; j++) {
401 Node *inn = n->in(j);
402 if (inn) {
403 if (inn->is_Mach() && must_clone[inn->as_Mach()->ideal_Opcode()] ) {
404 n_choice = 3;
405 break;
406 }
407 }
408 }
409
410 // MachTemps should be scheduled last so they are near their uses
411 if (n->is_MachTemp()) {
412 n_choice = 1;
413 }
414
415 uint n_latency = cfg->_node_latency.at_grow(n->_idx);
416 uint n_score = n->req(); // Many inputs get high score to break ties
417
418 // Keep best latency found
419 if( choice < n_choice ||
420 ( choice == n_choice &&
421 ( latency < n_latency ||
422 ( latency == n_latency &&
423 ( score < n_score ))))) {
424 choice = n_choice;
425 latency = n_latency;
426 score = n_score;
427 idx = i; // Also keep index in worklist
428 }
429 } // End of for all ready nodes in worklist
430
431 assert(idx >= 0, "index should be set");
432 Node *n = worklist[(uint)idx]; // Get the winner
433
434 worklist.map((uint)idx, worklist.pop()); // Compress worklist
435 return n;
436 }
437
438
439 //------------------------------set_next_call----------------------------------
440 void Block::set_next_call( Node *n, VectorSet &next_call, Block_Array &bbs ) {
441 if( next_call.test_set(n->_idx) ) return;
442 for( uint i=0; i<n->len(); i++ ) {
443 Node *m = n->in(i);
444 if( !m ) continue; // must see all nodes in block that precede call
445 if( bbs[m->_idx] == this )
446 set_next_call( m, next_call, bbs );
447 }
448 }
449
450 //------------------------------needed_for_next_call---------------------------
451 // Set the flag 'next_call' for each Node that is needed for the next call to
452 // be scheduled. This flag lets me bias scheduling so Nodes needed for the
453 // next subroutine call get priority - basically it moves things NOT needed
454 // for the next call till after the call. This prevents me from trying to
455 // carry lots of stuff live across a call.
456 void Block::needed_for_next_call(Node *this_call, VectorSet &next_call, Block_Array &bbs) {
457 // Find the next control-defining Node in this block
458 Node* call = NULL;
459 for (DUIterator_Fast imax, i = this_call->fast_outs(imax); i < imax; i++) {
460 Node* m = this_call->fast_out(i);
461 if( bbs[m->_idx] == this && // Local-block user
462 m != this_call && // Not self-start node
463 m->is_Call() )
464 call = m;
465 break;
466 }
467 if (call == NULL) return; // No next call (e.g., block end is near)
468 // Set next-call for all inputs to this call
469 set_next_call(call, next_call, bbs);
470 }
471
472 //------------------------------sched_call-------------------------------------
473 uint Block::sched_call( Matcher &matcher, Block_Array &bbs, uint node_cnt, Node_List &worklist, int *ready_cnt, MachCallNode *mcall, VectorSet &next_call ) {
474 RegMask regs;
475
476 // Schedule all the users of the call right now. All the users are
477 // projection Nodes, so they must be scheduled next to the call.
478 // Collect all the defined registers.
479 for (DUIterator_Fast imax, i = mcall->fast_outs(imax); i < imax; i++) {
480 Node* n = mcall->fast_out(i);
481 assert( n->Opcode()==Op_MachProj, "" );
482 --ready_cnt[n->_idx];
483 assert( !ready_cnt[n->_idx], "" );
484 // Schedule next to call
485 _nodes.map(node_cnt++, n);
486 // Collect defined registers
487 regs.OR(n->out_RegMask());
488 // Check for scheduling the next control-definer
489 if( n->bottom_type() == Type::CONTROL )
490 // Warm up next pile of heuristic bits
491 needed_for_next_call(n, next_call, bbs);
492
493 // Children of projections are now all ready
494 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
495 Node* m = n->fast_out(j); // Get user
496 if( bbs[m->_idx] != this ) continue;
497 if( m->is_Phi() ) continue;
498 if( !--ready_cnt[m->_idx] )
499 worklist.push(m);
500 }
501
502 }
503
504 // Act as if the call defines the Frame Pointer.
505 // Certainly the FP is alive and well after the call.
506 regs.Insert(matcher.c_frame_pointer());
507
508 // Set all registers killed and not already defined by the call.
509 uint r_cnt = mcall->tf()->range()->cnt();
510 int op = mcall->ideal_Opcode();
511 MachProjNode *proj = new (matcher.C, 1) MachProjNode( mcall, r_cnt+1, RegMask::Empty, MachProjNode::fat_proj );
512 bbs.map(proj->_idx,this);
513 _nodes.insert(node_cnt++, proj);
514
515 // Select the right register save policy.
516 const char * save_policy;
517 switch (op) {
518 case Op_CallRuntime:
519 case Op_CallLeaf:
520 case Op_CallLeafNoFP:
521 // Calling C code so use C calling convention
522 save_policy = matcher._c_reg_save_policy;
523 break;
524
525 case Op_CallStaticJava:
526 case Op_CallDynamicJava:
527 // Calling Java code so use Java calling convention
528 save_policy = matcher._register_save_policy;
529 break;
530
531 default:
532 ShouldNotReachHere();
533 }
534
535 // When using CallRuntime mark SOE registers as killed by the call
536 // so values that could show up in the RegisterMap aren't live in a
537 // callee saved register since the register wouldn't know where to
538 // find them. CallLeaf and CallLeafNoFP are ok because they can't
539 // have debug info on them. Strictly speaking this only needs to be
540 // done for oops since idealreg2debugmask takes care of debug info
541 // references but there no way to handle oops differently than other
542 // pointers as far as the kill mask goes.
543 bool exclude_soe = op == Op_CallRuntime;
544
545 // Fill in the kill mask for the call
546 for( OptoReg::Name r = OptoReg::Name(0); r < _last_Mach_Reg; r=OptoReg::add(r,1) ) {
547 if( !regs.Member(r) ) { // Not already defined by the call
548 // Save-on-call register?
549 if ((save_policy[r] == 'C') ||
550 (save_policy[r] == 'A') ||
551 ((save_policy[r] == 'E') && exclude_soe)) {
552 proj->_rout.Insert(r);
553 }
554 }
555 }
556
557 return node_cnt;
558 }
559
560
561 //------------------------------schedule_local---------------------------------
562 // Topological sort within a block. Someday become a real scheduler.
563 bool Block::schedule_local(PhaseCFG *cfg, Matcher &matcher, int *ready_cnt, VectorSet &next_call) {
564 // Already "sorted" are the block start Node (as the first entry), and
565 // the block-ending Node and any trailing control projections. We leave
566 // these alone. PhiNodes and ParmNodes are made to follow the block start
567 // Node. Everything else gets topo-sorted.
568
569 #ifndef PRODUCT
570 if (cfg->trace_opto_pipelining()) {
571 tty->print_cr("# --- schedule_local B%d, before: ---", _pre_order);
572 for (uint i = 0;i < _nodes.size();i++) {
573 tty->print("# ");
574 _nodes[i]->fast_dump();
575 }
576 tty->print_cr("#");
577 }
578 #endif
579
580 // RootNode is already sorted
581 if( _nodes.size() == 1 ) return true;
582
583 // Move PhiNodes and ParmNodes from 1 to cnt up to the start
584 uint node_cnt = end_idx();
585 uint phi_cnt = 1;
586 uint i;
587 for( i = 1; i<node_cnt; i++ ) { // Scan for Phi
588 Node *n = _nodes[i];
589 if( n->is_Phi() || // Found a PhiNode or ParmNode
590 (n->is_Proj() && n->in(0) == head()) ) {
591 // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt
592 _nodes.map(i,_nodes[phi_cnt]);
593 _nodes.map(phi_cnt++,n); // swap Phi/Parm up front
594 } else { // All others
595 // Count block-local inputs to 'n'
596 uint cnt = n->len(); // Input count
597 uint local = 0;
598 for( uint j=0; j<cnt; j++ ) {
599 Node *m = n->in(j);
600 if( m && cfg->_bbs[m->_idx] == this && !m->is_top() )
601 local++; // One more block-local input
602 }
603 ready_cnt[n->_idx] = local; // Count em up
604
605 // A few node types require changing a required edge to a precedence edge
606 // before allocation.
607 if( UseConcMarkSweepGC || UseG1GC ) {
608 if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_StoreCM ) {
609 // Note: Required edges with an index greater than oper_input_base
610 // are not supported by the allocator.
611 // Note2: Can only depend on unmatched edge being last,
612 // can not depend on its absolute position.
613 Node *oop_store = n->in(n->req() - 1);
614 n->del_req(n->req() - 1);
615 n->add_prec(oop_store);
616 assert(cfg->_bbs[oop_store->_idx]->_dom_depth <= this->_dom_depth, "oop_store must dominate card-mark");
617 }
618 }
619 if( n->is_Mach() && n->req() > TypeFunc::Parms &&
620 (n->as_Mach()->ideal_Opcode() == Op_MemBarAcquire ||
621 n->as_Mach()->ideal_Opcode() == Op_MemBarVolatile) ) {
622 // MemBarAcquire could be created without Precedent edge.
623 // del_req() replaces the specified edge with the last input edge
624 // and then removes the last edge. If the specified edge > number of
625 // edges the last edge will be moved outside of the input edges array
626 // and the edge will be lost. This is why this code should be
627 // executed only when Precedent (== TypeFunc::Parms) edge is present.
628 Node *x = n->in(TypeFunc::Parms);
629 n->del_req(TypeFunc::Parms);
630 n->add_prec(x);
631 }
632 }
633 }
634 for(uint i2=i; i2<_nodes.size(); i2++ ) // Trailing guys get zapped count
635 ready_cnt[_nodes[i2]->_idx] = 0;
636
637 // All the prescheduled guys do not hold back internal nodes
638 uint i3;
639 for(i3 = 0; i3<phi_cnt; i3++ ) { // For all pre-scheduled
640 Node *n = _nodes[i3]; // Get pre-scheduled
641 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
642 Node* m = n->fast_out(j);
643 if( cfg->_bbs[m->_idx] ==this ) // Local-block user
644 ready_cnt[m->_idx]--; // Fix ready count
645 }
646 }
647
648 Node_List delay;
649 // Make a worklist
650 Node_List worklist;
651 for(uint i4=i3; i4<node_cnt; i4++ ) { // Put ready guys on worklist
652 Node *m = _nodes[i4];
653 if( !ready_cnt[m->_idx] ) { // Zero ready count?
654 if (m->is_iteratively_computed()) {
655 // Push induction variable increments last to allow other uses
656 // of the phi to be scheduled first. The select() method breaks
657 // ties in scheduling by worklist order.
658 delay.push(m);
659 } else if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CreateEx) {
660 // Force the CreateEx to the top of the list so it's processed
661 // first and ends up at the start of the block.
662 worklist.insert(0, m);
663 } else {
664 worklist.push(m); // Then on to worklist!
665 }
666 }
667 }
668 while (delay.size()) {
669 Node* d = delay.pop();
670 worklist.push(d);
671 }
672
673 // Warm up the 'next_call' heuristic bits
674 needed_for_next_call(_nodes[0], next_call, cfg->_bbs);
675
676 #ifndef PRODUCT
677 if (cfg->trace_opto_pipelining()) {
678 for (uint j=0; j<_nodes.size(); j++) {
679 Node *n = _nodes[j];
680 int idx = n->_idx;
681 tty->print("# ready cnt:%3d ", ready_cnt[idx]);
682 tty->print("latency:%3d ", cfg->_node_latency.at_grow(idx));
683 tty->print("%4d: %s\n", idx, n->Name());
684 }
685 }
686 #endif
687
688 // Pull from worklist and schedule
689 while( worklist.size() ) { // Worklist is not ready
690
691 #ifndef PRODUCT
692 if (cfg->trace_opto_pipelining()) {
693 tty->print("# ready list:");
694 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
695 Node *n = worklist[i]; // Get Node on worklist
696 tty->print(" %d", n->_idx);
697 }
698 tty->cr();
699 }
700 #endif
701
702 // Select and pop a ready guy from worklist
703 Node* n = select(cfg, worklist, ready_cnt, next_call, phi_cnt);
704 _nodes.map(phi_cnt++,n); // Schedule him next
705
706 #ifndef PRODUCT
707 if (cfg->trace_opto_pipelining()) {
708 tty->print("# select %d: %s", n->_idx, n->Name());
709 tty->print(", latency:%d", cfg->_node_latency.at_grow(n->_idx));
710 n->dump();
711 if (Verbose) {
712 tty->print("# ready list:");
713 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
714 Node *n = worklist[i]; // Get Node on worklist
715 tty->print(" %d", n->_idx);
716 }
717 tty->cr();
718 }
719 }
720
721 #endif
722 if( n->is_MachCall() ) {
723 MachCallNode *mcall = n->as_MachCall();
724 phi_cnt = sched_call(matcher, cfg->_bbs, phi_cnt, worklist, ready_cnt, mcall, next_call);
725 continue;
726 }
727 // Children are now all ready
728 for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) {
729 Node* m = n->fast_out(i5); // Get user
730 if( cfg->_bbs[m->_idx] != this ) continue;
731 if( m->is_Phi() ) continue;
732 if( !--ready_cnt[m->_idx] )
733 worklist.push(m);
734 }
735 }
736
737 if( phi_cnt != end_idx() ) {
738 // did not schedule all. Retry, Bailout, or Die
739 Compile* C = matcher.C;
740 if (C->subsume_loads() == true && !C->failing()) {
741 // Retry with subsume_loads == false
742 // If this is the first failure, the sentinel string will "stick"
743 // to the Compile object, and the C2Compiler will see it and retry.
744 C->record_failure(C2Compiler::retry_no_subsuming_loads());
745 }
746 // assert( phi_cnt == end_idx(), "did not schedule all" );
747 return false;
748 }
749
750 #ifndef PRODUCT
751 if (cfg->trace_opto_pipelining()) {
752 tty->print_cr("#");
753 tty->print_cr("# after schedule_local");
754 for (uint i = 0;i < _nodes.size();i++) {
755 tty->print("# ");
756 _nodes[i]->fast_dump();
757 }
758 tty->cr();
759 }
760 #endif
761
762
763 return true;
764 }
765
766 //--------------------------catch_cleanup_fix_all_inputs-----------------------
767 static void catch_cleanup_fix_all_inputs(Node *use, Node *old_def, Node *new_def) {
768 for (uint l = 0; l < use->len(); l++) {
769 if (use->in(l) == old_def) {
770 if (l < use->req()) {
771 use->set_req(l, new_def);
772 } else {
773 use->rm_prec(l);
774 use->add_prec(new_def);
775 l--;
776 }
777 }
778 }
779 }
780
781 //------------------------------catch_cleanup_find_cloned_def------------------
782 static Node *catch_cleanup_find_cloned_def(Block *use_blk, Node *def, Block *def_blk, Block_Array &bbs, int n_clone_idx) {
783 assert( use_blk != def_blk, "Inter-block cleanup only");
784
785 // The use is some block below the Catch. Find and return the clone of the def
786 // that dominates the use. If there is no clone in a dominating block, then
787 // create a phi for the def in a dominating block.
788
789 // Find which successor block dominates this use. The successor
790 // blocks must all be single-entry (from the Catch only; I will have
791 // split blocks to make this so), hence they all dominate.
792 while( use_blk->_dom_depth > def_blk->_dom_depth+1 )
793 use_blk = use_blk->_idom;
794
795 // Find the successor
796 Node *fixup = NULL;
797
798 uint j;
799 for( j = 0; j < def_blk->_num_succs; j++ )
800 if( use_blk == def_blk->_succs[j] )
801 break;
802
803 if( j == def_blk->_num_succs ) {
804 // Block at same level in dom-tree is not a successor. It needs a
805 // PhiNode, the PhiNode uses from the def and IT's uses need fixup.
806 Node_Array inputs = new Node_List(Thread::current()->resource_area());
807 for(uint k = 1; k < use_blk->num_preds(); k++) {
808 inputs.map(k, catch_cleanup_find_cloned_def(bbs[use_blk->pred(k)->_idx], def, def_blk, bbs, n_clone_idx));
809 }
810
811 // Check to see if the use_blk already has an identical phi inserted.
812 // If it exists, it will be at the first position since all uses of a
813 // def are processed together.
814 Node *phi = use_blk->_nodes[1];
815 if( phi->is_Phi() ) {
816 fixup = phi;
817 for (uint k = 1; k < use_blk->num_preds(); k++) {
818 if (phi->in(k) != inputs[k]) {
819 // Not a match
820 fixup = NULL;
821 break;
822 }
823 }
824 }
825
826 // If an existing PhiNode was not found, make a new one.
827 if (fixup == NULL) {
828 Node *new_phi = PhiNode::make(use_blk->head(), def);
829 use_blk->_nodes.insert(1, new_phi);
830 bbs.map(new_phi->_idx, use_blk);
831 for (uint k = 1; k < use_blk->num_preds(); k++) {
832 new_phi->set_req(k, inputs[k]);
833 }
834 fixup = new_phi;
835 }
836
837 } else {
838 // Found the use just below the Catch. Make it use the clone.
839 fixup = use_blk->_nodes[n_clone_idx];
840 }
841
842 return fixup;
843 }
844
845 //--------------------------catch_cleanup_intra_block--------------------------
846 // Fix all input edges in use that reference "def". The use is in the same
847 // block as the def and both have been cloned in each successor block.
848 static void catch_cleanup_intra_block(Node *use, Node *def, Block *blk, int beg, int n_clone_idx) {
849
850 // Both the use and def have been cloned. For each successor block,
851 // get the clone of the use, and make its input the clone of the def
852 // found in that block.
853
854 uint use_idx = blk->find_node(use);
855 uint offset_idx = use_idx - beg;
856 for( uint k = 0; k < blk->_num_succs; k++ ) {
857 // Get clone in each successor block
858 Block *sb = blk->_succs[k];
859 Node *clone = sb->_nodes[offset_idx+1];
860 assert( clone->Opcode() == use->Opcode(), "" );
861
862 // Make use-clone reference the def-clone
863 catch_cleanup_fix_all_inputs(clone, def, sb->_nodes[n_clone_idx]);
864 }
865 }
866
867 //------------------------------catch_cleanup_inter_block---------------------
868 // Fix all input edges in use that reference "def". The use is in a different
869 // block than the def.
870 static void catch_cleanup_inter_block(Node *use, Block *use_blk, Node *def, Block *def_blk, Block_Array &bbs, int n_clone_idx) {
871 if( !use_blk ) return; // Can happen if the use is a precedence edge
872
873 Node *new_def = catch_cleanup_find_cloned_def(use_blk, def, def_blk, bbs, n_clone_idx);
874 catch_cleanup_fix_all_inputs(use, def, new_def);
875 }
876
877 //------------------------------call_catch_cleanup-----------------------------
878 // If we inserted any instructions between a Call and his CatchNode,
879 // clone the instructions on all paths below the Catch.
880 void Block::call_catch_cleanup(Block_Array &bbs) {
881
882 // End of region to clone
883 uint end = end_idx();
884 if( !_nodes[end]->is_Catch() ) return;
885 // Start of region to clone
886 uint beg = end;
887 while( _nodes[beg-1]->Opcode() != Op_MachProj ||
888 !_nodes[beg-1]->in(0)->is_Call() ) {
889 beg--;
890 assert(beg > 0,"Catch cleanup walking beyond block boundary");
891 }
892 // Range of inserted instructions is [beg, end)
893 if( beg == end ) return;
894
895 // Clone along all Catch output paths. Clone area between the 'beg' and
896 // 'end' indices.
897 for( uint i = 0; i < _num_succs; i++ ) {
898 Block *sb = _succs[i];
899 // Clone the entire area; ignoring the edge fixup for now.
900 for( uint j = end; j > beg; j-- ) {
901 Node *clone = _nodes[j-1]->clone();
902 sb->_nodes.insert( 1, clone );
903 bbs.map(clone->_idx,sb);
904 }
905 }
906
907
908 // Fixup edges. Check the def-use info per cloned Node
909 for(uint i2 = beg; i2 < end; i2++ ) {
910 uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block
911 Node *n = _nodes[i2]; // Node that got cloned
912 // Need DU safe iterator because of edge manipulation in calls.
913 Unique_Node_List *out = new Unique_Node_List(Thread::current()->resource_area());
914 for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) {
915 out->push(n->fast_out(j1));
916 }
917 uint max = out->size();
918 for (uint j = 0; j < max; j++) {// For all users
919 Node *use = out->pop();
920 Block *buse = bbs[use->_idx];
921 if( use->is_Phi() ) {
922 for( uint k = 1; k < use->req(); k++ )
923 if( use->in(k) == n ) {
924 Node *fixup = catch_cleanup_find_cloned_def(bbs[buse->pred(k)->_idx], n, this, bbs, n_clone_idx);
925 use->set_req(k, fixup);
926 }
927 } else {
928 if (this == buse) {
929 catch_cleanup_intra_block(use, n, this, beg, n_clone_idx);
930 } else {
931 catch_cleanup_inter_block(use, buse, n, this, bbs, n_clone_idx);
932 }
933 }
934 } // End for all users
935
936 } // End of for all Nodes in cloned area
937
938 // Remove the now-dead cloned ops
939 for(uint i3 = beg; i3 < end; i3++ ) {
940 _nodes[beg]->disconnect_inputs(NULL);
941 _nodes.remove(beg);
942 }
943
944 // If the successor blocks have a CreateEx node, move it back to the top
945 for(uint i4 = 0; i4 < _num_succs; i4++ ) {
946 Block *sb = _succs[i4];
947 uint new_cnt = end - beg;
948 // Remove any newly created, but dead, nodes.
949 for( uint j = new_cnt; j > 0; j-- ) {
950 Node *n = sb->_nodes[j];
951 if (n->outcnt() == 0 &&
952 (!n->is_Proj() || n->as_Proj()->in(0)->outcnt() == 1) ){
953 n->disconnect_inputs(NULL);
954 sb->_nodes.remove(j);
955 new_cnt--;
956 }
957 }
958 // If any newly created nodes remain, move the CreateEx node to the top
959 if (new_cnt > 0) {
960 Node *cex = sb->_nodes[1+new_cnt];
961 if( cex->is_Mach() && cex->as_Mach()->ideal_Opcode() == Op_CreateEx ) {
962 sb->_nodes.remove(1+new_cnt);
963 sb->_nodes.insert(1,cex);
964 }
965 }
966 }
967 }