1 /* 2 * Copyright (c) 1998, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "memory/allocation.inline.hpp" 27 #include "opto/block.hpp" 28 #include "opto/c2compiler.hpp" 29 #include "opto/callnode.hpp" 30 #include "opto/cfgnode.hpp" 31 #include "opto/machnode.hpp" 32 #include "opto/runtime.hpp" 33 #if defined AD_MD_HPP 34 # include AD_MD_HPP 35 #elif defined TARGET_ARCH_MODEL_x86_32 36 # include "adfiles/ad_x86_32.hpp" 37 #elif defined TARGET_ARCH_MODEL_x86_64 38 # include "adfiles/ad_x86_64.hpp" 39 #elif defined TARGET_ARCH_MODEL_aarch64 40 # include "adfiles/ad_aarch64.hpp" 41 #elif defined TARGET_ARCH_MODEL_sparc 42 # include "adfiles/ad_sparc.hpp" 43 #elif defined TARGET_ARCH_MODEL_zero 44 # include "adfiles/ad_zero.hpp" 45 #elif defined TARGET_ARCH_MODEL_ppc_64 46 # include "adfiles/ad_ppc_64.hpp" 47 #endif 48 49 // Optimization - Graph Style 50 51 // Check whether val is not-null-decoded compressed oop, 52 // i.e. will grab into the base of the heap if it represents NULL. 53 static bool accesses_heap_base_zone(Node *val) { 54 if (Universe::narrow_oop_base() != NULL) { // Implies UseCompressedOops. 55 if (val && val->is_Mach()) { 56 if (val->as_Mach()->ideal_Opcode() == Op_DecodeN) { 57 // This assumes all Decodes with TypePtr::NotNull are matched to nodes that 58 // decode NULL to point to the heap base (Decode_NN). 59 if (val->bottom_type()->is_oopptr()->ptr() == TypePtr::NotNull) { 60 return true; 61 } 62 } 63 // Must recognize load operation with Decode matched in memory operand. 64 // We should not reach here exept for PPC/AIX, as os::zero_page_read_protected() 65 // returns true everywhere else. On PPC, no such memory operands 66 // exist, therefore we did not yet implement a check for such operands. 67 NOT_AIX(Unimplemented()); 68 } 69 } 70 return false; 71 } 72 73 static bool needs_explicit_null_check_for_read(Node *val) { 74 // On some OSes (AIX) the page at address 0 is only write protected. 75 // If so, only Store operations will trap. 76 if (os::zero_page_read_protected()) { 77 return false; // Implicit null check will work. 78 } 79 // Also a read accessing the base of a heap-based compressed heap will trap. 80 if (accesses_heap_base_zone(val) && // Hits the base zone page. 81 Universe::narrow_oop_use_implicit_null_checks()) { // Base zone page is protected. 82 return false; 83 } 84 85 return true; 86 } 87 88 //------------------------------implicit_null_check---------------------------- 89 // Detect implicit-null-check opportunities. Basically, find NULL checks 90 // with suitable memory ops nearby. Use the memory op to do the NULL check. 91 // I can generate a memory op if there is not one nearby. 92 // The proj is the control projection for the not-null case. 93 // The val is the pointer being checked for nullness or 94 // decodeHeapOop_not_null node if it did not fold into address. 95 void PhaseCFG::implicit_null_check(Block* block, Node *proj, Node *val, int allowed_reasons) { 96 // Assume if null check need for 0 offset then always needed 97 // Intel solaris doesn't support any null checks yet and no 98 // mechanism exists (yet) to set the switches at an os_cpu level 99 if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return; 100 101 // Make sure the ptr-is-null path appears to be uncommon! 102 float f = block->end()->as_MachIf()->_prob; 103 if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f; 104 if( f > PROB_UNLIKELY_MAG(4) ) return; 105 106 uint bidx = 0; // Capture index of value into memop 107 bool was_store; // Memory op is a store op 108 109 // Get the successor block for if the test ptr is non-null 110 Block* not_null_block; // this one goes with the proj 111 Block* null_block; 112 if (block->get_node(block->number_of_nodes()-1) == proj) { 113 null_block = block->_succs[0]; 114 not_null_block = block->_succs[1]; 115 } else { 116 assert(block->get_node(block->number_of_nodes()-2) == proj, "proj is one or the other"); 117 not_null_block = block->_succs[0]; 118 null_block = block->_succs[1]; 119 } 120 while (null_block->is_Empty() == Block::empty_with_goto) { 121 null_block = null_block->_succs[0]; 122 } 123 124 // Search the exception block for an uncommon trap. 125 // (See Parse::do_if and Parse::do_ifnull for the reason 126 // we need an uncommon trap. Briefly, we need a way to 127 // detect failure of this optimization, as in 6366351.) 128 { 129 bool found_trap = false; 130 for (uint i1 = 0; i1 < null_block->number_of_nodes(); i1++) { 131 Node* nn = null_block->get_node(i1); 132 if (nn->is_MachCall() && 133 nn->as_MachCall()->entry_point() == SharedRuntime::uncommon_trap_blob()->entry_point()) { 134 const Type* trtype = nn->in(TypeFunc::Parms)->bottom_type(); 135 if (trtype->isa_int() && trtype->is_int()->is_con()) { 136 jint tr_con = trtype->is_int()->get_con(); 137 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(tr_con); 138 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(tr_con); 139 assert((int)reason < (int)BitsPerInt, "recode bit map"); 140 if (is_set_nth_bit(allowed_reasons, (int) reason) 141 && action != Deoptimization::Action_none) { 142 // This uncommon trap is sure to recompile, eventually. 143 // When that happens, C->too_many_traps will prevent 144 // this transformation from happening again. 145 found_trap = true; 146 } 147 } 148 break; 149 } 150 } 151 if (!found_trap) { 152 // We did not find an uncommon trap. 153 return; 154 } 155 } 156 157 // Check for decodeHeapOop_not_null node which did not fold into address 158 bool is_decoden = ((intptr_t)val) & 1; 159 val = (Node*)(((intptr_t)val) & ~1); 160 161 assert(!is_decoden || (val->in(0) == NULL) && val->is_Mach() && 162 (val->as_Mach()->ideal_Opcode() == Op_DecodeN), "sanity"); 163 164 // Search the successor block for a load or store who's base value is also 165 // the tested value. There may be several. 166 Node_List *out = new Node_List(Thread::current()->resource_area()); 167 MachNode *best = NULL; // Best found so far 168 for (DUIterator i = val->outs(); val->has_out(i); i++) { 169 Node *m = val->out(i); 170 if( !m->is_Mach() ) continue; 171 MachNode *mach = m->as_Mach(); 172 was_store = false; 173 int iop = mach->ideal_Opcode(); 174 switch( iop ) { 175 case Op_LoadB: 176 case Op_LoadUB: 177 case Op_LoadUS: 178 case Op_LoadD: 179 case Op_LoadF: 180 case Op_LoadI: 181 case Op_LoadL: 182 case Op_LoadP: 183 case Op_LoadN: 184 case Op_LoadS: 185 case Op_LoadKlass: 186 case Op_LoadNKlass: 187 case Op_LoadRange: 188 case Op_LoadD_unaligned: 189 case Op_LoadL_unaligned: 190 case Op_StoreB: 191 case Op_StoreC: 192 case Op_StoreCM: 193 case Op_StoreD: 194 case Op_StoreF: 195 case Op_StoreI: 196 case Op_StoreL: 197 case Op_StoreP: 198 case Op_StoreN: 199 case Op_StoreNKlass: 200 was_store = true; // Memory op is a store op 201 // Stores will have their address in slot 2 (memory in slot 1). 202 // If the value being nul-checked is in another slot, it means we 203 // are storing the checked value, which does NOT check the value! 204 if( mach->in(2) != val ) continue; 205 break; // Found a memory op? 206 case Op_StrComp: 207 case Op_StrEquals: 208 case Op_StrIndexOf: 209 case Op_AryEq: 210 case Op_EncodeISOArray: 211 // Not a legit memory op for implicit null check regardless of 212 // embedded loads 213 continue; 214 default: // Also check for embedded loads 215 if( !mach->needs_anti_dependence_check() ) 216 continue; // Not an memory op; skip it 217 if( must_clone[iop] ) { 218 // Do not move nodes which produce flags because 219 // RA will try to clone it to place near branch and 220 // it will cause recompilation, see clone_node(). 221 continue; 222 } 223 { 224 // Check that value is used in memory address in 225 // instructions with embedded load (CmpP val1,(val2+off)). 226 Node* base; 227 Node* index; 228 const MachOper* oper = mach->memory_inputs(base, index); 229 if (oper == NULL || oper == (MachOper*)-1) { 230 continue; // Not an memory op; skip it 231 } 232 if (val == base || 233 val == index && val->bottom_type()->isa_narrowoop()) { 234 break; // Found it 235 } else { 236 continue; // Skip it 237 } 238 } 239 break; 240 } 241 242 // On some OSes (AIX) the page at address 0 is only write protected. 243 // If so, only Store operations will trap. 244 // But a read accessing the base of a heap-based compressed heap will trap. 245 if (!was_store && needs_explicit_null_check_for_read(val)) { 246 continue; 247 } 248 249 // Check that node's control edge is not-null block's head or dominates it, 250 // otherwise we can't hoist it because there are other control dependencies. 251 Node* ctrl = mach->in(0); 252 if (ctrl != NULL && !(ctrl == not_null_block->head() || 253 get_block_for_node(ctrl)->dominates(not_null_block))) { 254 continue; 255 } 256 257 // check if the offset is not too high for implicit exception 258 { 259 intptr_t offset = 0; 260 const TypePtr *adr_type = NULL; // Do not need this return value here 261 const Node* base = mach->get_base_and_disp(offset, adr_type); 262 if (base == NULL || base == NodeSentinel) { 263 // Narrow oop address doesn't have base, only index 264 if( val->bottom_type()->isa_narrowoop() && 265 MacroAssembler::needs_explicit_null_check(offset) ) 266 continue; // Give up if offset is beyond page size 267 // cannot reason about it; is probably not implicit null exception 268 } else { 269 const TypePtr* tptr; 270 if (UseCompressedOops && (Universe::narrow_oop_shift() == 0 || 271 Universe::narrow_klass_shift() == 0)) { 272 // 32-bits narrow oop can be the base of address expressions 273 tptr = base->get_ptr_type(); 274 } else { 275 // only regular oops are expected here 276 tptr = base->bottom_type()->is_ptr(); 277 } 278 // Give up if offset is not a compile-time constant 279 if( offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot ) 280 continue; 281 offset += tptr->_offset; // correct if base is offseted 282 if( MacroAssembler::needs_explicit_null_check(offset) ) 283 continue; // Give up is reference is beyond 4K page size 284 } 285 } 286 287 // Check ctrl input to see if the null-check dominates the memory op 288 Block *cb = get_block_for_node(mach); 289 cb = cb->_idom; // Always hoist at least 1 block 290 if( !was_store ) { // Stores can be hoisted only one block 291 while( cb->_dom_depth > (block->_dom_depth + 1)) 292 cb = cb->_idom; // Hoist loads as far as we want 293 // The non-null-block should dominate the memory op, too. Live 294 // range spilling will insert a spill in the non-null-block if it is 295 // needs to spill the memory op for an implicit null check. 296 if (cb->_dom_depth == (block->_dom_depth + 1)) { 297 if (cb != not_null_block) continue; 298 cb = cb->_idom; 299 } 300 } 301 if( cb != block ) continue; 302 303 // Found a memory user; see if it can be hoisted to check-block 304 uint vidx = 0; // Capture index of value into memop 305 uint j; 306 for( j = mach->req()-1; j > 0; j-- ) { 307 if( mach->in(j) == val ) { 308 vidx = j; 309 // Ignore DecodeN val which could be hoisted to where needed. 310 if( is_decoden ) continue; 311 } 312 // Block of memory-op input 313 Block *inb = get_block_for_node(mach->in(j)); 314 Block *b = block; // Start from nul check 315 while( b != inb && b->_dom_depth > inb->_dom_depth ) 316 b = b->_idom; // search upwards for input 317 // See if input dominates null check 318 if( b != inb ) 319 break; 320 } 321 if( j > 0 ) 322 continue; 323 Block *mb = get_block_for_node(mach); 324 // Hoisting stores requires more checks for the anti-dependence case. 325 // Give up hoisting if we have to move the store past any load. 326 if( was_store ) { 327 Block *b = mb; // Start searching here for a local load 328 // mach use (faulting) trying to hoist 329 // n might be blocker to hoisting 330 while( b != block ) { 331 uint k; 332 for( k = 1; k < b->number_of_nodes(); k++ ) { 333 Node *n = b->get_node(k); 334 if( n->needs_anti_dependence_check() && 335 n->in(LoadNode::Memory) == mach->in(StoreNode::Memory) ) 336 break; // Found anti-dependent load 337 } 338 if( k < b->number_of_nodes() ) 339 break; // Found anti-dependent load 340 // Make sure control does not do a merge (would have to check allpaths) 341 if( b->num_preds() != 2 ) break; 342 b = get_block_for_node(b->pred(1)); // Move up to predecessor block 343 } 344 if( b != block ) continue; 345 } 346 347 // Make sure this memory op is not already being used for a NullCheck 348 Node *e = mb->end(); 349 if( e->is_MachNullCheck() && e->in(1) == mach ) 350 continue; // Already being used as a NULL check 351 352 // Found a candidate! Pick one with least dom depth - the highest 353 // in the dom tree should be closest to the null check. 354 if (best == NULL || get_block_for_node(mach)->_dom_depth < get_block_for_node(best)->_dom_depth) { 355 best = mach; 356 bidx = vidx; 357 } 358 } 359 // No candidate! 360 if (best == NULL) { 361 return; 362 } 363 364 // ---- Found an implicit null check 365 extern int implicit_null_checks; 366 implicit_null_checks++; 367 368 if( is_decoden ) { 369 // Check if we need to hoist decodeHeapOop_not_null first. 370 Block *valb = get_block_for_node(val); 371 if( block != valb && block->_dom_depth < valb->_dom_depth ) { 372 // Hoist it up to the end of the test block. 373 valb->find_remove(val); 374 block->add_inst(val); 375 map_node_to_block(val, block); 376 // DecodeN on x86 may kill flags. Check for flag-killing projections 377 // that also need to be hoisted. 378 for (DUIterator_Fast jmax, j = val->fast_outs(jmax); j < jmax; j++) { 379 Node* n = val->fast_out(j); 380 if( n->is_MachProj() ) { 381 get_block_for_node(n)->find_remove(n); 382 block->add_inst(n); 383 map_node_to_block(n, block); 384 } 385 } 386 } 387 } 388 // Hoist the memory candidate up to the end of the test block. 389 Block *old_block = get_block_for_node(best); 390 old_block->find_remove(best); 391 block->add_inst(best); 392 map_node_to_block(best, block); 393 394 // Move the control dependence if it is pinned to not-null block. 395 // Don't change it in other cases: NULL or dominating control. 396 if (best->in(0) == not_null_block->head()) { 397 // Set it to control edge of null check. 398 best->set_req(0, proj->in(0)->in(0)); 399 } 400 401 // Check for flag-killing projections that also need to be hoisted 402 // Should be DU safe because no edge updates. 403 for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) { 404 Node* n = best->fast_out(j); 405 if( n->is_MachProj() ) { 406 get_block_for_node(n)->find_remove(n); 407 block->add_inst(n); 408 map_node_to_block(n, block); 409 } 410 } 411 412 // proj==Op_True --> ne test; proj==Op_False --> eq test. 413 // One of two graph shapes got matched: 414 // (IfTrue (If (Bool NE (CmpP ptr NULL)))) 415 // (IfFalse (If (Bool EQ (CmpP ptr NULL)))) 416 // NULL checks are always branch-if-eq. If we see a IfTrue projection 417 // then we are replacing a 'ne' test with a 'eq' NULL check test. 418 // We need to flip the projections to keep the same semantics. 419 if( proj->Opcode() == Op_IfTrue ) { 420 // Swap order of projections in basic block to swap branch targets 421 Node *tmp1 = block->get_node(block->end_idx()+1); 422 Node *tmp2 = block->get_node(block->end_idx()+2); 423 block->map_node(tmp2, block->end_idx()+1); 424 block->map_node(tmp1, block->end_idx()+2); 425 Node *tmp = new (C) Node(C->top()); // Use not NULL input 426 tmp1->replace_by(tmp); 427 tmp2->replace_by(tmp1); 428 tmp->replace_by(tmp2); 429 tmp->destruct(); 430 } 431 432 // Remove the existing null check; use a new implicit null check instead. 433 // Since schedule-local needs precise def-use info, we need to correct 434 // it as well. 435 Node *old_tst = proj->in(0); 436 MachNode *nul_chk = new (C) MachNullCheckNode(old_tst->in(0),best,bidx); 437 block->map_node(nul_chk, block->end_idx()); 438 map_node_to_block(nul_chk, block); 439 // Redirect users of old_test to nul_chk 440 for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2) 441 old_tst->last_out(i2)->set_req(0, nul_chk); 442 // Clean-up any dead code 443 for (uint i3 = 0; i3 < old_tst->req(); i3++) { 444 Node* in = old_tst->in(i3); 445 old_tst->set_req(i3, NULL); 446 if (in->outcnt() == 0) { 447 // Remove dead input node 448 in->disconnect_inputs(NULL, C); 449 block->find_remove(in); 450 } 451 } 452 453 latency_from_uses(nul_chk); 454 latency_from_uses(best); 455 456 // insert anti-dependences to defs in this block 457 if (! best->needs_anti_dependence_check()) { 458 for (uint k = 1; k < block->number_of_nodes(); k++) { 459 Node *n = block->get_node(k); 460 if (n->needs_anti_dependence_check() && 461 n->in(LoadNode::Memory) == best->in(StoreNode::Memory)) { 462 // Found anti-dependent load 463 insert_anti_dependences(block, n); 464 } 465 } 466 } 467 } 468 469 470 //------------------------------select----------------------------------------- 471 // Select a nice fellow from the worklist to schedule next. If there is only 472 // one choice, then use it. Projections take top priority for correctness 473 // reasons - if I see a projection, then it is next. There are a number of 474 // other special cases, for instructions that consume condition codes, et al. 475 // These are chosen immediately. Some instructions are required to immediately 476 // precede the last instruction in the block, and these are taken last. Of the 477 // remaining cases (most), choose the instruction with the greatest latency 478 // (that is, the most number of pseudo-cycles required to the end of the 479 // routine). If there is a tie, choose the instruction with the most inputs. 480 Node* PhaseCFG::select(Block* block, Node_List &worklist, GrowableArray<int> &ready_cnt, VectorSet &next_call, uint sched_slot) { 481 482 // If only a single entry on the stack, use it 483 uint cnt = worklist.size(); 484 if (cnt == 1) { 485 Node *n = worklist[0]; 486 worklist.map(0,worklist.pop()); 487 return n; 488 } 489 490 uint choice = 0; // Bigger is most important 491 uint latency = 0; // Bigger is scheduled first 492 uint score = 0; // Bigger is better 493 int idx = -1; // Index in worklist 494 int cand_cnt = 0; // Candidate count 495 496 for( uint i=0; i<cnt; i++ ) { // Inspect entire worklist 497 // Order in worklist is used to break ties. 498 // See caller for how this is used to delay scheduling 499 // of induction variable increments to after the other 500 // uses of the phi are scheduled. 501 Node *n = worklist[i]; // Get Node on worklist 502 503 int iop = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : 0; 504 if( n->is_Proj() || // Projections always win 505 n->Opcode()== Op_Con || // So does constant 'Top' 506 iop == Op_CreateEx || // Create-exception must start block 507 iop == Op_CheckCastPP 508 ) { 509 worklist.map(i,worklist.pop()); 510 return n; 511 } 512 513 // Final call in a block must be adjacent to 'catch' 514 Node *e = block->end(); 515 if( e->is_Catch() && e->in(0)->in(0) == n ) 516 continue; 517 518 // Memory op for an implicit null check has to be at the end of the block 519 if( e->is_MachNullCheck() && e->in(1) == n ) 520 continue; 521 522 // Schedule IV increment last. 523 if (e->is_Mach() && e->as_Mach()->ideal_Opcode() == Op_CountedLoopEnd && 524 e->in(1)->in(1) == n && n->is_iteratively_computed()) 525 continue; 526 527 uint n_choice = 2; 528 529 // See if this instruction is consumed by a branch. If so, then (as the 530 // branch is the last instruction in the basic block) force it to the 531 // end of the basic block 532 if ( must_clone[iop] ) { 533 // See if any use is a branch 534 bool found_machif = false; 535 536 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 537 Node* use = n->fast_out(j); 538 539 // The use is a conditional branch, make them adjacent 540 if (use->is_MachIf() && get_block_for_node(use) == block) { 541 found_machif = true; 542 break; 543 } 544 545 // More than this instruction pending for successor to be ready, 546 // don't choose this if other opportunities are ready 547 if (ready_cnt.at(use->_idx) > 1) 548 n_choice = 1; 549 } 550 551 // loop terminated, prefer not to use this instruction 552 if (found_machif) 553 continue; 554 } 555 556 // See if this has a predecessor that is "must_clone", i.e. sets the 557 // condition code. If so, choose this first 558 for (uint j = 0; j < n->req() ; j++) { 559 Node *inn = n->in(j); 560 if (inn) { 561 if (inn->is_Mach() && must_clone[inn->as_Mach()->ideal_Opcode()] ) { 562 n_choice = 3; 563 break; 564 } 565 } 566 } 567 568 // MachTemps should be scheduled last so they are near their uses 569 if (n->is_MachTemp()) { 570 n_choice = 1; 571 } 572 573 uint n_latency = get_latency_for_node(n); 574 uint n_score = n->req(); // Many inputs get high score to break ties 575 576 // Keep best latency found 577 cand_cnt++; 578 if (choice < n_choice || 579 (choice == n_choice && 580 ((StressLCM && Compile::randomized_select(cand_cnt)) || 581 (!StressLCM && 582 (latency < n_latency || 583 (latency == n_latency && 584 (score < n_score))))))) { 585 choice = n_choice; 586 latency = n_latency; 587 score = n_score; 588 idx = i; // Also keep index in worklist 589 } 590 } // End of for all ready nodes in worklist 591 592 assert(idx >= 0, "index should be set"); 593 Node *n = worklist[(uint)idx]; // Get the winner 594 595 worklist.map((uint)idx, worklist.pop()); // Compress worklist 596 return n; 597 } 598 599 600 //------------------------------set_next_call---------------------------------- 601 void PhaseCFG::set_next_call(Block* block, Node* n, VectorSet& next_call) { 602 if( next_call.test_set(n->_idx) ) return; 603 for( uint i=0; i<n->len(); i++ ) { 604 Node *m = n->in(i); 605 if( !m ) continue; // must see all nodes in block that precede call 606 if (get_block_for_node(m) == block) { 607 set_next_call(block, m, next_call); 608 } 609 } 610 } 611 612 //------------------------------needed_for_next_call--------------------------- 613 // Set the flag 'next_call' for each Node that is needed for the next call to 614 // be scheduled. This flag lets me bias scheduling so Nodes needed for the 615 // next subroutine call get priority - basically it moves things NOT needed 616 // for the next call till after the call. This prevents me from trying to 617 // carry lots of stuff live across a call. 618 void PhaseCFG::needed_for_next_call(Block* block, Node* this_call, VectorSet& next_call) { 619 // Find the next control-defining Node in this block 620 Node* call = NULL; 621 for (DUIterator_Fast imax, i = this_call->fast_outs(imax); i < imax; i++) { 622 Node* m = this_call->fast_out(i); 623 if (get_block_for_node(m) == block && // Local-block user 624 m != this_call && // Not self-start node 625 m->is_MachCall()) { 626 call = m; 627 break; 628 } 629 } 630 if (call == NULL) return; // No next call (e.g., block end is near) 631 // Set next-call for all inputs to this call 632 set_next_call(block, call, next_call); 633 } 634 635 //------------------------------add_call_kills------------------------------------- 636 // helper function that adds caller save registers to MachProjNode 637 static void add_call_kills(MachProjNode *proj, RegMask& regs, const char* save_policy, bool exclude_soe) { 638 // Fill in the kill mask for the call 639 for( OptoReg::Name r = OptoReg::Name(0); r < _last_Mach_Reg; r=OptoReg::add(r,1) ) { 640 if( !regs.Member(r) ) { // Not already defined by the call 641 // Save-on-call register? 642 if ((save_policy[r] == 'C') || 643 (save_policy[r] == 'A') || 644 ((save_policy[r] == 'E') && exclude_soe)) { 645 proj->_rout.Insert(r); 646 } 647 } 648 } 649 } 650 651 652 //------------------------------sched_call------------------------------------- 653 uint PhaseCFG::sched_call(Block* block, uint node_cnt, Node_List& worklist, GrowableArray<int>& ready_cnt, MachCallNode* mcall, VectorSet& next_call) { 654 RegMask regs; 655 656 // Schedule all the users of the call right now. All the users are 657 // projection Nodes, so they must be scheduled next to the call. 658 // Collect all the defined registers. 659 for (DUIterator_Fast imax, i = mcall->fast_outs(imax); i < imax; i++) { 660 Node* n = mcall->fast_out(i); 661 assert( n->is_MachProj(), "" ); 662 int n_cnt = ready_cnt.at(n->_idx)-1; 663 ready_cnt.at_put(n->_idx, n_cnt); 664 assert( n_cnt == 0, "" ); 665 // Schedule next to call 666 block->map_node(n, node_cnt++); 667 // Collect defined registers 668 regs.OR(n->out_RegMask()); 669 // Check for scheduling the next control-definer 670 if( n->bottom_type() == Type::CONTROL ) 671 // Warm up next pile of heuristic bits 672 needed_for_next_call(block, n, next_call); 673 674 // Children of projections are now all ready 675 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 676 Node* m = n->fast_out(j); // Get user 677 if(get_block_for_node(m) != block) { 678 continue; 679 } 680 if( m->is_Phi() ) continue; 681 int m_cnt = ready_cnt.at(m->_idx)-1; 682 ready_cnt.at_put(m->_idx, m_cnt); 683 if( m_cnt == 0 ) 684 worklist.push(m); 685 } 686 687 } 688 689 // Act as if the call defines the Frame Pointer. 690 // Certainly the FP is alive and well after the call. 691 regs.Insert(_matcher.c_frame_pointer()); 692 693 // Set all registers killed and not already defined by the call. 694 uint r_cnt = mcall->tf()->range()->cnt(); 695 int op = mcall->ideal_Opcode(); 696 MachProjNode *proj = new (C) MachProjNode( mcall, r_cnt+1, RegMask::Empty, MachProjNode::fat_proj ); 697 map_node_to_block(proj, block); 698 block->insert_node(proj, node_cnt++); 699 700 // Select the right register save policy. 701 const char *save_policy = NULL; 702 switch (op) { 703 case Op_CallRuntime: 704 case Op_CallLeaf: 705 case Op_CallLeafNoFP: 706 // Calling C code so use C calling convention 707 save_policy = _matcher._c_reg_save_policy; 708 break; 709 710 case Op_CallStaticJava: 711 case Op_CallDynamicJava: 712 // Calling Java code so use Java calling convention 713 save_policy = _matcher._register_save_policy; 714 break; 715 716 default: 717 ShouldNotReachHere(); 718 } 719 720 // When using CallRuntime mark SOE registers as killed by the call 721 // so values that could show up in the RegisterMap aren't live in a 722 // callee saved register since the register wouldn't know where to 723 // find them. CallLeaf and CallLeafNoFP are ok because they can't 724 // have debug info on them. Strictly speaking this only needs to be 725 // done for oops since idealreg2debugmask takes care of debug info 726 // references but there no way to handle oops differently than other 727 // pointers as far as the kill mask goes. 728 bool exclude_soe = op == Op_CallRuntime; 729 730 // If the call is a MethodHandle invoke, we need to exclude the 731 // register which is used to save the SP value over MH invokes from 732 // the mask. Otherwise this register could be used for 733 // deoptimization information. 734 if (op == Op_CallStaticJava) { 735 MachCallStaticJavaNode* mcallstaticjava = (MachCallStaticJavaNode*) mcall; 736 if (mcallstaticjava->_method_handle_invoke) 737 proj->_rout.OR(Matcher::method_handle_invoke_SP_save_mask()); 738 } 739 740 add_call_kills(proj, regs, save_policy, exclude_soe); 741 742 return node_cnt; 743 } 744 745 746 //------------------------------schedule_local--------------------------------- 747 // Topological sort within a block. Someday become a real scheduler. 748 bool PhaseCFG::schedule_local(Block* block, GrowableArray<int>& ready_cnt, VectorSet& next_call) { 749 // Already "sorted" are the block start Node (as the first entry), and 750 // the block-ending Node and any trailing control projections. We leave 751 // these alone. PhiNodes and ParmNodes are made to follow the block start 752 // Node. Everything else gets topo-sorted. 753 754 #ifndef PRODUCT 755 if (trace_opto_pipelining()) { 756 tty->print_cr("# --- schedule_local B%d, before: ---", block->_pre_order); 757 for (uint i = 0;i < block->number_of_nodes(); i++) { 758 tty->print("# "); 759 block->get_node(i)->fast_dump(); 760 } 761 tty->print_cr("#"); 762 } 763 #endif 764 765 // RootNode is already sorted 766 if (block->number_of_nodes() == 1) { 767 return true; 768 } 769 770 // Move PhiNodes and ParmNodes from 1 to cnt up to the start 771 uint node_cnt = block->end_idx(); 772 uint phi_cnt = 1; 773 uint i; 774 for( i = 1; i<node_cnt; i++ ) { // Scan for Phi 775 Node *n = block->get_node(i); 776 if( n->is_Phi() || // Found a PhiNode or ParmNode 777 (n->is_Proj() && n->in(0) == block->head()) ) { 778 // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt 779 block->map_node(block->get_node(phi_cnt), i); 780 block->map_node(n, phi_cnt++); // swap Phi/Parm up front 781 } else { // All others 782 // Count block-local inputs to 'n' 783 uint cnt = n->len(); // Input count 784 uint local = 0; 785 for( uint j=0; j<cnt; j++ ) { 786 Node *m = n->in(j); 787 if( m && get_block_for_node(m) == block && !m->is_top() ) 788 local++; // One more block-local input 789 } 790 ready_cnt.at_put(n->_idx, local); // Count em up 791 792 #ifdef ASSERT 793 if( UseConcMarkSweepGC || UseG1GC ) { 794 if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_StoreCM ) { 795 // Check the precedence edges 796 for (uint prec = n->req(); prec < n->len(); prec++) { 797 Node* oop_store = n->in(prec); 798 if (oop_store != NULL) { 799 assert(get_block_for_node(oop_store)->_dom_depth <= block->_dom_depth, "oop_store must dominate card-mark"); 800 } 801 } 802 } 803 } 804 #endif 805 806 // A few node types require changing a required edge to a precedence edge 807 // before allocation. 808 if( n->is_Mach() && n->req() > TypeFunc::Parms && 809 (n->as_Mach()->ideal_Opcode() == Op_MemBarAcquire || 810 n->as_Mach()->ideal_Opcode() == Op_MemBarVolatile) ) { 811 // MemBarAcquire could be created without Precedent edge. 812 // del_req() replaces the specified edge with the last input edge 813 // and then removes the last edge. If the specified edge > number of 814 // edges the last edge will be moved outside of the input edges array 815 // and the edge will be lost. This is why this code should be 816 // executed only when Precedent (== TypeFunc::Parms) edge is present. 817 Node *x = n->in(TypeFunc::Parms); 818 if (x != NULL && get_block_for_node(x) == block && n->find_prec_edge(x) != -1) { 819 // Old edge to node within same block will get removed, but no precedence 820 // edge will get added because it already exists. Update ready count. 821 int cnt = ready_cnt.at(n->_idx); 822 assert(cnt > 1, err_msg("MemBar node %d must not get ready here", n->_idx)); 823 ready_cnt.at_put(n->_idx, cnt-1); 824 } 825 n->del_req(TypeFunc::Parms); 826 n->add_prec(x); 827 } 828 } 829 } 830 for(uint i2=i; i2< block->number_of_nodes(); i2++ ) // Trailing guys get zapped count 831 ready_cnt.at_put(block->get_node(i2)->_idx, 0); 832 833 // All the prescheduled guys do not hold back internal nodes 834 uint i3; 835 for(i3 = 0; i3<phi_cnt; i3++ ) { // For all pre-scheduled 836 Node *n = block->get_node(i3); // Get pre-scheduled 837 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { 838 Node* m = n->fast_out(j); 839 if (get_block_for_node(m) == block) { // Local-block user 840 int m_cnt = ready_cnt.at(m->_idx)-1; 841 ready_cnt.at_put(m->_idx, m_cnt); // Fix ready count 842 } 843 } 844 } 845 846 Node_List delay; 847 // Make a worklist 848 Node_List worklist; 849 for(uint i4=i3; i4<node_cnt; i4++ ) { // Put ready guys on worklist 850 Node *m = block->get_node(i4); 851 if( !ready_cnt.at(m->_idx) ) { // Zero ready count? 852 if (m->is_iteratively_computed()) { 853 // Push induction variable increments last to allow other uses 854 // of the phi to be scheduled first. The select() method breaks 855 // ties in scheduling by worklist order. 856 delay.push(m); 857 } else if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CreateEx) { 858 // Force the CreateEx to the top of the list so it's processed 859 // first and ends up at the start of the block. 860 worklist.insert(0, m); 861 } else { 862 worklist.push(m); // Then on to worklist! 863 } 864 } 865 } 866 while (delay.size()) { 867 Node* d = delay.pop(); 868 worklist.push(d); 869 } 870 871 // Warm up the 'next_call' heuristic bits 872 needed_for_next_call(block, block->head(), next_call); 873 874 #ifndef PRODUCT 875 if (trace_opto_pipelining()) { 876 for (uint j=0; j< block->number_of_nodes(); j++) { 877 Node *n = block->get_node(j); 878 int idx = n->_idx; 879 tty->print("# ready cnt:%3d ", ready_cnt.at(idx)); 880 tty->print("latency:%3d ", get_latency_for_node(n)); 881 tty->print("%4d: %s\n", idx, n->Name()); 882 } 883 } 884 #endif 885 886 uint max_idx = (uint)ready_cnt.length(); 887 // Pull from worklist and schedule 888 while( worklist.size() ) { // Worklist is not ready 889 890 #ifndef PRODUCT 891 if (trace_opto_pipelining()) { 892 tty->print("# ready list:"); 893 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist 894 Node *n = worklist[i]; // Get Node on worklist 895 tty->print(" %d", n->_idx); 896 } 897 tty->cr(); 898 } 899 #endif 900 901 // Select and pop a ready guy from worklist 902 Node* n = select(block, worklist, ready_cnt, next_call, phi_cnt); 903 block->map_node(n, phi_cnt++); // Schedule him next 904 905 #ifndef PRODUCT 906 if (trace_opto_pipelining()) { 907 tty->print("# select %d: %s", n->_idx, n->Name()); 908 tty->print(", latency:%d", get_latency_for_node(n)); 909 n->dump(); 910 if (Verbose) { 911 tty->print("# ready list:"); 912 for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist 913 Node *n = worklist[i]; // Get Node on worklist 914 tty->print(" %d", n->_idx); 915 } 916 tty->cr(); 917 } 918 } 919 920 #endif 921 if( n->is_MachCall() ) { 922 MachCallNode *mcall = n->as_MachCall(); 923 phi_cnt = sched_call(block, phi_cnt, worklist, ready_cnt, mcall, next_call); 924 continue; 925 } 926 927 if (n->is_Mach() && n->as_Mach()->has_call()) { 928 RegMask regs; 929 regs.Insert(_matcher.c_frame_pointer()); 930 regs.OR(n->out_RegMask()); 931 932 MachProjNode *proj = new (C) MachProjNode( n, 1, RegMask::Empty, MachProjNode::fat_proj ); 933 map_node_to_block(proj, block); 934 block->insert_node(proj, phi_cnt++); 935 936 add_call_kills(proj, regs, _matcher._c_reg_save_policy, false); 937 } 938 939 // Children are now all ready 940 for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) { 941 Node* m = n->fast_out(i5); // Get user 942 if (get_block_for_node(m) != block) { 943 continue; 944 } 945 if( m->is_Phi() ) continue; 946 if (m->_idx >= max_idx) { // new node, skip it 947 assert(m->is_MachProj() && n->is_Mach() && n->as_Mach()->has_call(), "unexpected node types"); 948 continue; 949 } 950 int m_cnt = ready_cnt.at(m->_idx)-1; 951 ready_cnt.at_put(m->_idx, m_cnt); 952 if( m_cnt == 0 ) 953 worklist.push(m); 954 } 955 } 956 957 if( phi_cnt != block->end_idx() ) { 958 // did not schedule all. Retry, Bailout, or Die 959 if (C->subsume_loads() == true && !C->failing()) { 960 // Retry with subsume_loads == false 961 // If this is the first failure, the sentinel string will "stick" 962 // to the Compile object, and the C2Compiler will see it and retry. 963 C->record_failure(C2Compiler::retry_no_subsuming_loads()); 964 } else { 965 assert(false, "graph should be schedulable"); 966 } 967 // assert( phi_cnt == end_idx(), "did not schedule all" ); 968 return false; 969 } 970 971 #ifndef PRODUCT 972 if (trace_opto_pipelining()) { 973 tty->print_cr("#"); 974 tty->print_cr("# after schedule_local"); 975 for (uint i = 0;i < block->number_of_nodes();i++) { 976 tty->print("# "); 977 block->get_node(i)->fast_dump(); 978 } 979 tty->cr(); 980 } 981 #endif 982 983 984 return true; 985 } 986 987 //--------------------------catch_cleanup_fix_all_inputs----------------------- 988 static void catch_cleanup_fix_all_inputs(Node *use, Node *old_def, Node *new_def) { 989 for (uint l = 0; l < use->len(); l++) { 990 if (use->in(l) == old_def) { 991 if (l < use->req()) { 992 use->set_req(l, new_def); 993 } else { 994 use->rm_prec(l); 995 use->add_prec(new_def); 996 l--; 997 } 998 } 999 } 1000 } 1001 1002 //------------------------------catch_cleanup_find_cloned_def------------------ 1003 Node* PhaseCFG::catch_cleanup_find_cloned_def(Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) { 1004 assert( use_blk != def_blk, "Inter-block cleanup only"); 1005 1006 // The use is some block below the Catch. Find and return the clone of the def 1007 // that dominates the use. If there is no clone in a dominating block, then 1008 // create a phi for the def in a dominating block. 1009 1010 // Find which successor block dominates this use. The successor 1011 // blocks must all be single-entry (from the Catch only; I will have 1012 // split blocks to make this so), hence they all dominate. 1013 while( use_blk->_dom_depth > def_blk->_dom_depth+1 ) 1014 use_blk = use_blk->_idom; 1015 1016 // Find the successor 1017 Node *fixup = NULL; 1018 1019 uint j; 1020 for( j = 0; j < def_blk->_num_succs; j++ ) 1021 if( use_blk == def_blk->_succs[j] ) 1022 break; 1023 1024 if( j == def_blk->_num_succs ) { 1025 // Block at same level in dom-tree is not a successor. It needs a 1026 // PhiNode, the PhiNode uses from the def and IT's uses need fixup. 1027 Node_Array inputs = new Node_List(Thread::current()->resource_area()); 1028 for(uint k = 1; k < use_blk->num_preds(); k++) { 1029 Block* block = get_block_for_node(use_blk->pred(k)); 1030 inputs.map(k, catch_cleanup_find_cloned_def(block, def, def_blk, n_clone_idx)); 1031 } 1032 1033 // Check to see if the use_blk already has an identical phi inserted. 1034 // If it exists, it will be at the first position since all uses of a 1035 // def are processed together. 1036 Node *phi = use_blk->get_node(1); 1037 if( phi->is_Phi() ) { 1038 fixup = phi; 1039 for (uint k = 1; k < use_blk->num_preds(); k++) { 1040 if (phi->in(k) != inputs[k]) { 1041 // Not a match 1042 fixup = NULL; 1043 break; 1044 } 1045 } 1046 } 1047 1048 // If an existing PhiNode was not found, make a new one. 1049 if (fixup == NULL) { 1050 Node *new_phi = PhiNode::make(use_blk->head(), def); 1051 use_blk->insert_node(new_phi, 1); 1052 map_node_to_block(new_phi, use_blk); 1053 for (uint k = 1; k < use_blk->num_preds(); k++) { 1054 new_phi->set_req(k, inputs[k]); 1055 } 1056 fixup = new_phi; 1057 } 1058 1059 } else { 1060 // Found the use just below the Catch. Make it use the clone. 1061 fixup = use_blk->get_node(n_clone_idx); 1062 } 1063 1064 return fixup; 1065 } 1066 1067 //--------------------------catch_cleanup_intra_block-------------------------- 1068 // Fix all input edges in use that reference "def". The use is in the same 1069 // block as the def and both have been cloned in each successor block. 1070 static void catch_cleanup_intra_block(Node *use, Node *def, Block *blk, int beg, int n_clone_idx) { 1071 1072 // Both the use and def have been cloned. For each successor block, 1073 // get the clone of the use, and make its input the clone of the def 1074 // found in that block. 1075 1076 uint use_idx = blk->find_node(use); 1077 uint offset_idx = use_idx - beg; 1078 for( uint k = 0; k < blk->_num_succs; k++ ) { 1079 // Get clone in each successor block 1080 Block *sb = blk->_succs[k]; 1081 Node *clone = sb->get_node(offset_idx+1); 1082 assert( clone->Opcode() == use->Opcode(), "" ); 1083 1084 // Make use-clone reference the def-clone 1085 catch_cleanup_fix_all_inputs(clone, def, sb->get_node(n_clone_idx)); 1086 } 1087 } 1088 1089 //------------------------------catch_cleanup_inter_block--------------------- 1090 // Fix all input edges in use that reference "def". The use is in a different 1091 // block than the def. 1092 void PhaseCFG::catch_cleanup_inter_block(Node *use, Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) { 1093 if( !use_blk ) return; // Can happen if the use is a precedence edge 1094 1095 Node *new_def = catch_cleanup_find_cloned_def(use_blk, def, def_blk, n_clone_idx); 1096 catch_cleanup_fix_all_inputs(use, def, new_def); 1097 } 1098 1099 //------------------------------call_catch_cleanup----------------------------- 1100 // If we inserted any instructions between a Call and his CatchNode, 1101 // clone the instructions on all paths below the Catch. 1102 void PhaseCFG::call_catch_cleanup(Block* block) { 1103 1104 // End of region to clone 1105 uint end = block->end_idx(); 1106 if( !block->get_node(end)->is_Catch() ) return; 1107 // Start of region to clone 1108 uint beg = end; 1109 while(!block->get_node(beg-1)->is_MachProj() || 1110 !block->get_node(beg-1)->in(0)->is_MachCall() ) { 1111 beg--; 1112 assert(beg > 0,"Catch cleanup walking beyond block boundary"); 1113 } 1114 // Range of inserted instructions is [beg, end) 1115 if( beg == end ) return; 1116 1117 // Clone along all Catch output paths. Clone area between the 'beg' and 1118 // 'end' indices. 1119 for( uint i = 0; i < block->_num_succs; i++ ) { 1120 Block *sb = block->_succs[i]; 1121 // Clone the entire area; ignoring the edge fixup for now. 1122 for( uint j = end; j > beg; j-- ) { 1123 Node *clone = block->get_node(j-1)->clone(); 1124 sb->insert_node(clone, 1); 1125 map_node_to_block(clone, sb); 1126 if (clone->needs_anti_dependence_check()) { 1127 insert_anti_dependences(sb, clone); 1128 } 1129 } 1130 } 1131 1132 1133 // Fixup edges. Check the def-use info per cloned Node 1134 for(uint i2 = beg; i2 < end; i2++ ) { 1135 uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block 1136 Node *n = block->get_node(i2); // Node that got cloned 1137 // Need DU safe iterator because of edge manipulation in calls. 1138 Unique_Node_List *out = new Unique_Node_List(Thread::current()->resource_area()); 1139 for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) { 1140 out->push(n->fast_out(j1)); 1141 } 1142 uint max = out->size(); 1143 for (uint j = 0; j < max; j++) {// For all users 1144 Node *use = out->pop(); 1145 Block *buse = get_block_for_node(use); 1146 if( use->is_Phi() ) { 1147 for( uint k = 1; k < use->req(); k++ ) 1148 if( use->in(k) == n ) { 1149 Block* b = get_block_for_node(buse->pred(k)); 1150 Node *fixup = catch_cleanup_find_cloned_def(b, n, block, n_clone_idx); 1151 use->set_req(k, fixup); 1152 } 1153 } else { 1154 if (block == buse) { 1155 catch_cleanup_intra_block(use, n, block, beg, n_clone_idx); 1156 } else { 1157 catch_cleanup_inter_block(use, buse, n, block, n_clone_idx); 1158 } 1159 } 1160 } // End for all users 1161 1162 } // End of for all Nodes in cloned area 1163 1164 // Remove the now-dead cloned ops 1165 for(uint i3 = beg; i3 < end; i3++ ) { 1166 block->get_node(beg)->disconnect_inputs(NULL, C); 1167 block->remove_node(beg); 1168 } 1169 1170 // If the successor blocks have a CreateEx node, move it back to the top 1171 for(uint i4 = 0; i4 < block->_num_succs; i4++ ) { 1172 Block *sb = block->_succs[i4]; 1173 uint new_cnt = end - beg; 1174 // Remove any newly created, but dead, nodes. 1175 for( uint j = new_cnt; j > 0; j-- ) { 1176 Node *n = sb->get_node(j); 1177 if (n->outcnt() == 0 && 1178 (!n->is_Proj() || n->as_Proj()->in(0)->outcnt() == 1) ){ 1179 n->disconnect_inputs(NULL, C); 1180 sb->remove_node(j); 1181 new_cnt--; 1182 } 1183 } 1184 // If any newly created nodes remain, move the CreateEx node to the top 1185 if (new_cnt > 0) { 1186 Node *cex = sb->get_node(1+new_cnt); 1187 if( cex->is_Mach() && cex->as_Mach()->ideal_Opcode() == Op_CreateEx ) { 1188 sb->remove_node(1+new_cnt); 1189 sb->insert_node(cex, 1); 1190 } 1191 } 1192 } 1193 }