1 /* 2 * Copyright (c) 1997, 2023, 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 "ci/ciFlatArrayKlass.hpp" 27 #include "classfile/javaClasses.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "compiler/compileLog.hpp" 30 #include "gc/shared/barrierSet.hpp" 31 #include "gc/shared/c2/barrierSetC2.hpp" 32 #include "gc/shared/tlab_globals.hpp" 33 #include "memory/allocation.inline.hpp" 34 #include "memory/resourceArea.hpp" 35 #include "oops/objArrayKlass.hpp" 36 #include "opto/addnode.hpp" 37 #include "opto/arraycopynode.hpp" 38 #include "opto/cfgnode.hpp" 39 #include "opto/regalloc.hpp" 40 #include "opto/compile.hpp" 41 #include "opto/connode.hpp" 42 #include "opto/convertnode.hpp" 43 #include "opto/inlinetypenode.hpp" 44 #include "opto/loopnode.hpp" 45 #include "opto/machnode.hpp" 46 #include "opto/matcher.hpp" 47 #include "opto/memnode.hpp" 48 #include "opto/mulnode.hpp" 49 #include "opto/narrowptrnode.hpp" 50 #include "opto/phaseX.hpp" 51 #include "opto/regmask.hpp" 52 #include "opto/rootnode.hpp" 53 #include "opto/vectornode.hpp" 54 #include "utilities/align.hpp" 55 #include "utilities/copy.hpp" 56 #include "utilities/macros.hpp" 57 #include "utilities/powerOfTwo.hpp" 58 #include "utilities/vmError.hpp" 59 60 // Portions of code courtesy of Clifford Click 61 62 // Optimization - Graph Style 63 64 static Node *step_through_mergemem(PhaseGVN *phase, MergeMemNode *mmem, const TypePtr *tp, const TypePtr *adr_check, outputStream *st); 65 66 //============================================================================= 67 uint MemNode::size_of() const { return sizeof(*this); } 68 69 const TypePtr *MemNode::adr_type() const { 70 Node* adr = in(Address); 71 if (adr == NULL) return NULL; // node is dead 72 const TypePtr* cross_check = NULL; 73 DEBUG_ONLY(cross_check = _adr_type); 74 return calculate_adr_type(adr->bottom_type(), cross_check); 75 } 76 77 bool MemNode::check_if_adr_maybe_raw(Node* adr) { 78 if (adr != NULL) { 79 if (adr->bottom_type()->base() == Type::RawPtr || adr->bottom_type()->base() == Type::AnyPtr) { 80 return true; 81 } 82 } 83 return false; 84 } 85 86 #ifndef PRODUCT 87 void MemNode::dump_spec(outputStream *st) const { 88 if (in(Address) == NULL) return; // node is dead 89 #ifndef ASSERT 90 // fake the missing field 91 const TypePtr* _adr_type = NULL; 92 if (in(Address) != NULL) 93 _adr_type = in(Address)->bottom_type()->isa_ptr(); 94 #endif 95 dump_adr_type(this, _adr_type, st); 96 97 Compile* C = Compile::current(); 98 if (C->alias_type(_adr_type)->is_volatile()) { 99 st->print(" Volatile!"); 100 } 101 if (_unaligned_access) { 102 st->print(" unaligned"); 103 } 104 if (_mismatched_access) { 105 st->print(" mismatched"); 106 } 107 if (_unsafe_access) { 108 st->print(" unsafe"); 109 } 110 } 111 112 void MemNode::dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st) { 113 st->print(" @"); 114 if (adr_type == NULL) { 115 st->print("NULL"); 116 } else { 117 adr_type->dump_on(st); 118 Compile* C = Compile::current(); 119 Compile::AliasType* atp = NULL; 120 if (C->have_alias_type(adr_type)) atp = C->alias_type(adr_type); 121 if (atp == NULL) 122 st->print(", idx=?\?;"); 123 else if (atp->index() == Compile::AliasIdxBot) 124 st->print(", idx=Bot;"); 125 else if (atp->index() == Compile::AliasIdxTop) 126 st->print(", idx=Top;"); 127 else if (atp->index() == Compile::AliasIdxRaw) 128 st->print(", idx=Raw;"); 129 else { 130 ciField* field = atp->field(); 131 if (field) { 132 st->print(", name="); 133 field->print_name_on(st); 134 } 135 st->print(", idx=%d;", atp->index()); 136 } 137 } 138 } 139 140 extern void print_alias_types(); 141 142 #endif 143 144 Node *MemNode::optimize_simple_memory_chain(Node *mchain, const TypeOopPtr *t_oop, Node *load, PhaseGVN *phase) { 145 assert((t_oop != NULL), "sanity"); 146 bool is_instance = t_oop->is_known_instance_field(); 147 bool is_boxed_value_load = t_oop->is_ptr_to_boxed_value() && 148 (load != NULL) && load->is_Load() && 149 (phase->is_IterGVN() != NULL); 150 if (!(is_instance || is_boxed_value_load)) 151 return mchain; // don't try to optimize non-instance types 152 uint instance_id = t_oop->instance_id(); 153 Node *start_mem = phase->C->start()->proj_out_or_null(TypeFunc::Memory); 154 Node *prev = NULL; 155 Node *result = mchain; 156 while (prev != result) { 157 prev = result; 158 if (result == start_mem) 159 break; // hit one of our sentinels 160 // skip over a call which does not affect this memory slice 161 if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) { 162 Node *proj_in = result->in(0); 163 if (proj_in->is_Allocate() && proj_in->_idx == instance_id) { 164 break; // hit one of our sentinels 165 } else if (proj_in->is_Call()) { 166 // ArrayCopyNodes processed here as well 167 CallNode *call = proj_in->as_Call(); 168 if (!call->may_modify(t_oop, phase)) { // returns false for instances 169 result = call->in(TypeFunc::Memory); 170 } 171 } else if (proj_in->is_Initialize()) { 172 AllocateNode* alloc = proj_in->as_Initialize()->allocation(); 173 // Stop if this is the initialization for the object instance which 174 // contains this memory slice, otherwise skip over it. 175 if ((alloc == NULL) || (alloc->_idx == instance_id)) { 176 break; 177 } 178 if (is_instance) { 179 result = proj_in->in(TypeFunc::Memory); 180 } else if (is_boxed_value_load) { 181 Node* klass = alloc->in(AllocateNode::KlassNode); 182 const TypeKlassPtr* tklass = phase->type(klass)->is_klassptr(); 183 if (tklass->klass_is_exact() && !tklass->exact_klass()->equals(t_oop->is_instptr()->exact_klass())) { 184 result = proj_in->in(TypeFunc::Memory); // not related allocation 185 } 186 } 187 } else if (proj_in->is_MemBar()) { 188 ArrayCopyNode* ac = NULL; 189 if (ArrayCopyNode::may_modify(t_oop, proj_in->as_MemBar(), phase, ac)) { 190 break; 191 } 192 result = proj_in->in(TypeFunc::Memory); 193 } else { 194 assert(false, "unexpected projection"); 195 } 196 } else if (result->is_ClearArray()) { 197 if (!is_instance || !ClearArrayNode::step_through(&result, instance_id, phase)) { 198 // Can not bypass initialization of the instance 199 // we are looking for. 200 break; 201 } 202 // Otherwise skip it (the call updated 'result' value). 203 } else if (result->is_MergeMem()) { 204 result = step_through_mergemem(phase, result->as_MergeMem(), t_oop, NULL, tty); 205 } 206 } 207 return result; 208 } 209 210 Node *MemNode::optimize_memory_chain(Node *mchain, const TypePtr *t_adr, Node *load, PhaseGVN *phase) { 211 const TypeOopPtr* t_oop = t_adr->isa_oopptr(); 212 if (t_oop == NULL) 213 return mchain; // don't try to optimize non-oop types 214 Node* result = optimize_simple_memory_chain(mchain, t_oop, load, phase); 215 bool is_instance = t_oop->is_known_instance_field(); 216 PhaseIterGVN *igvn = phase->is_IterGVN(); 217 if (is_instance && igvn != NULL && result->is_Phi()) { 218 PhiNode *mphi = result->as_Phi(); 219 assert(mphi->bottom_type() == Type::MEMORY, "memory phi required"); 220 const TypePtr *t = mphi->adr_type(); 221 bool do_split = false; 222 // In the following cases, Load memory input can be further optimized based on 223 // its precise address type 224 if (t == TypePtr::BOTTOM || t == TypeRawPtr::BOTTOM ) { 225 do_split = true; 226 } else if (t->isa_oopptr() && !t->is_oopptr()->is_known_instance()) { 227 const TypeOopPtr* mem_t = 228 t->is_oopptr()->cast_to_exactness(true) 229 ->is_oopptr()->cast_to_ptr_type(t_oop->ptr()) 230 ->is_oopptr()->cast_to_instance_id(t_oop->instance_id()); 231 if (t_oop->is_aryptr()) { 232 mem_t = mem_t->is_aryptr() 233 ->cast_to_stable(t_oop->is_aryptr()->is_stable()) 234 ->cast_to_size(t_oop->is_aryptr()->size()) 235 ->with_offset(t_oop->is_aryptr()->offset()) 236 ->is_aryptr(); 237 } 238 do_split = mem_t == t_oop; 239 } 240 if (do_split) { 241 // clone the Phi with our address type 242 result = mphi->split_out_instance(t_adr, igvn); 243 } else { 244 assert(phase->C->get_alias_index(t) == phase->C->get_alias_index(t_adr), "correct memory chain"); 245 } 246 } 247 return result; 248 } 249 250 static Node *step_through_mergemem(PhaseGVN *phase, MergeMemNode *mmem, const TypePtr *tp, const TypePtr *adr_check, outputStream *st) { 251 uint alias_idx = phase->C->get_alias_index(tp); 252 Node *mem = mmem; 253 #ifdef ASSERT 254 { 255 // Check that current type is consistent with the alias index used during graph construction 256 assert(alias_idx >= Compile::AliasIdxRaw, "must not be a bad alias_idx"); 257 bool consistent = adr_check == NULL || adr_check->empty() || 258 phase->C->must_alias(adr_check, alias_idx ); 259 // Sometimes dead array references collapse to a[-1], a[-2], or a[-3] 260 if( !consistent && adr_check != NULL && !adr_check->empty() && 261 tp->isa_aryptr() && tp->offset() == Type::OffsetBot && 262 adr_check->isa_aryptr() && adr_check->offset() != Type::OffsetBot && 263 ( adr_check->offset() == arrayOopDesc::length_offset_in_bytes() || 264 adr_check->offset() == oopDesc::klass_offset_in_bytes() || 265 adr_check->offset() == oopDesc::mark_offset_in_bytes() ) ) { 266 // don't assert if it is dead code. 267 consistent = true; 268 } 269 if( !consistent ) { 270 st->print("alias_idx==%d, adr_check==", alias_idx); 271 if( adr_check == NULL ) { 272 st->print("NULL"); 273 } else { 274 adr_check->dump(); 275 } 276 st->cr(); 277 print_alias_types(); 278 assert(consistent, "adr_check must match alias idx"); 279 } 280 } 281 #endif 282 // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally 283 // means an array I have not precisely typed yet. Do not do any 284 // alias stuff with it any time soon. 285 const TypeOopPtr *toop = tp->isa_oopptr(); 286 if (tp->base() != Type::AnyPtr && 287 !(toop && 288 toop->isa_instptr() && 289 toop->is_instptr()->instance_klass()->is_java_lang_Object() && 290 toop->offset() == Type::OffsetBot)) { 291 // compress paths and change unreachable cycles to TOP 292 // If not, we can update the input infinitely along a MergeMem cycle 293 // Equivalent code in PhiNode::Ideal 294 Node* m = phase->transform(mmem); 295 // If transformed to a MergeMem, get the desired slice 296 // Otherwise the returned node represents memory for every slice 297 mem = (m->is_MergeMem())? m->as_MergeMem()->memory_at(alias_idx) : m; 298 // Update input if it is progress over what we have now 299 } 300 return mem; 301 } 302 303 //--------------------------Ideal_common--------------------------------------- 304 // Look for degenerate control and memory inputs. Bypass MergeMem inputs. 305 // Unhook non-raw memories from complete (macro-expanded) initializations. 306 Node *MemNode::Ideal_common(PhaseGVN *phase, bool can_reshape) { 307 // If our control input is a dead region, kill all below the region 308 Node *ctl = in(MemNode::Control); 309 if (ctl && remove_dead_region(phase, can_reshape)) 310 return this; 311 ctl = in(MemNode::Control); 312 // Don't bother trying to transform a dead node 313 if (ctl && ctl->is_top()) return NodeSentinel; 314 315 PhaseIterGVN *igvn = phase->is_IterGVN(); 316 // Wait if control on the worklist. 317 if (ctl && can_reshape && igvn != NULL) { 318 Node* bol = NULL; 319 Node* cmp = NULL; 320 if (ctl->in(0)->is_If()) { 321 assert(ctl->is_IfTrue() || ctl->is_IfFalse(), "sanity"); 322 bol = ctl->in(0)->in(1); 323 if (bol->is_Bool()) 324 cmp = ctl->in(0)->in(1)->in(1); 325 } 326 if (igvn->_worklist.member(ctl) || 327 (bol != NULL && igvn->_worklist.member(bol)) || 328 (cmp != NULL && igvn->_worklist.member(cmp)) ) { 329 // This control path may be dead. 330 // Delay this memory node transformation until the control is processed. 331 igvn->_worklist.push(this); 332 return NodeSentinel; // caller will return NULL 333 } 334 } 335 // Ignore if memory is dead, or self-loop 336 Node *mem = in(MemNode::Memory); 337 if (phase->type( mem ) == Type::TOP) return NodeSentinel; // caller will return NULL 338 assert(mem != this, "dead loop in MemNode::Ideal"); 339 340 if (can_reshape && igvn != NULL && igvn->_worklist.member(mem)) { 341 // This memory slice may be dead. 342 // Delay this mem node transformation until the memory is processed. 343 igvn->_worklist.push(this); 344 return NodeSentinel; // caller will return NULL 345 } 346 347 Node *address = in(MemNode::Address); 348 const Type *t_adr = phase->type(address); 349 if (t_adr == Type::TOP) return NodeSentinel; // caller will return NULL 350 351 if (can_reshape && is_unsafe_access() && (t_adr == TypePtr::NULL_PTR)) { 352 // Unsafe off-heap access with zero address. Remove access and other control users 353 // to not confuse optimizations and add a HaltNode to fail if this is ever executed. 354 assert(ctl != NULL, "unsafe accesses should be control dependent"); 355 for (DUIterator_Fast imax, i = ctl->fast_outs(imax); i < imax; i++) { 356 Node* u = ctl->fast_out(i); 357 if (u != ctl) { 358 igvn->rehash_node_delayed(u); 359 int nb = u->replace_edge(ctl, phase->C->top(), igvn); 360 --i, imax -= nb; 361 } 362 } 363 Node* frame = igvn->transform(new ParmNode(phase->C->start(), TypeFunc::FramePtr)); 364 Node* halt = igvn->transform(new HaltNode(ctl, frame, "unsafe off-heap access with zero address")); 365 phase->C->root()->add_req(halt); 366 return this; 367 } 368 369 if (can_reshape && igvn != NULL && 370 (igvn->_worklist.member(address) || 371 (igvn->_worklist.size() > 0 && t_adr != adr_type())) ) { 372 // The address's base and type may change when the address is processed. 373 // Delay this mem node transformation until the address is processed. 374 igvn->_worklist.push(this); 375 return NodeSentinel; // caller will return NULL 376 } 377 378 // Do NOT remove or optimize the next lines: ensure a new alias index 379 // is allocated for an oop pointer type before Escape Analysis. 380 // Note: C++ will not remove it since the call has side effect. 381 if (t_adr->isa_oopptr()) { 382 int alias_idx = phase->C->get_alias_index(t_adr->is_ptr()); 383 } 384 385 Node* base = NULL; 386 if (address->is_AddP()) { 387 base = address->in(AddPNode::Base); 388 } 389 if (base != NULL && phase->type(base)->higher_equal(TypePtr::NULL_PTR) && 390 !t_adr->isa_rawptr()) { 391 // Note: raw address has TOP base and top->higher_equal(TypePtr::NULL_PTR) is true. 392 // Skip this node optimization if its address has TOP base. 393 return NodeSentinel; // caller will return NULL 394 } 395 396 // Avoid independent memory operations 397 Node* old_mem = mem; 398 399 // The code which unhooks non-raw memories from complete (macro-expanded) 400 // initializations was removed. After macro-expansion all stores caught 401 // by Initialize node became raw stores and there is no information 402 // which memory slices they modify. So it is unsafe to move any memory 403 // operation above these stores. Also in most cases hooked non-raw memories 404 // were already unhooked by using information from detect_ptr_independence() 405 // and find_previous_store(). 406 407 if (mem->is_MergeMem()) { 408 MergeMemNode* mmem = mem->as_MergeMem(); 409 const TypePtr *tp = t_adr->is_ptr(); 410 411 mem = step_through_mergemem(phase, mmem, tp, adr_type(), tty); 412 } 413 414 if (mem != old_mem) { 415 set_req_X(MemNode::Memory, mem, phase); 416 if (phase->type(mem) == Type::TOP) return NodeSentinel; 417 return this; 418 } 419 420 // let the subclass continue analyzing... 421 return NULL; 422 } 423 424 // Helper function for proving some simple control dominations. 425 // Attempt to prove that all control inputs of 'dom' dominate 'sub'. 426 // Already assumes that 'dom' is available at 'sub', and that 'sub' 427 // is not a constant (dominated by the method's StartNode). 428 // Used by MemNode::find_previous_store to prove that the 429 // control input of a memory operation predates (dominates) 430 // an allocation it wants to look past. 431 bool MemNode::all_controls_dominate(Node* dom, Node* sub) { 432 if (dom == NULL || dom->is_top() || sub == NULL || sub->is_top()) 433 return false; // Conservative answer for dead code 434 435 // Check 'dom'. Skip Proj and CatchProj nodes. 436 dom = dom->find_exact_control(dom); 437 if (dom == NULL || dom->is_top()) 438 return false; // Conservative answer for dead code 439 440 if (dom == sub) { 441 // For the case when, for example, 'sub' is Initialize and the original 442 // 'dom' is Proj node of the 'sub'. 443 return false; 444 } 445 446 if (dom->is_Con() || dom->is_Start() || dom->is_Root() || dom == sub) 447 return true; 448 449 // 'dom' dominates 'sub' if its control edge and control edges 450 // of all its inputs dominate or equal to sub's control edge. 451 452 // Currently 'sub' is either Allocate, Initialize or Start nodes. 453 // Or Region for the check in LoadNode::Ideal(); 454 // 'sub' should have sub->in(0) != NULL. 455 assert(sub->is_Allocate() || sub->is_Initialize() || sub->is_Start() || 456 sub->is_Region() || sub->is_Call(), "expecting only these nodes"); 457 458 // Get control edge of 'sub'. 459 Node* orig_sub = sub; 460 sub = sub->find_exact_control(sub->in(0)); 461 if (sub == NULL || sub->is_top()) 462 return false; // Conservative answer for dead code 463 464 assert(sub->is_CFG(), "expecting control"); 465 466 if (sub == dom) 467 return true; 468 469 if (sub->is_Start() || sub->is_Root()) 470 return false; 471 472 { 473 // Check all control edges of 'dom'. 474 475 ResourceMark rm; 476 Node_List nlist; 477 Unique_Node_List dom_list; 478 479 dom_list.push(dom); 480 bool only_dominating_controls = false; 481 482 for (uint next = 0; next < dom_list.size(); next++) { 483 Node* n = dom_list.at(next); 484 if (n == orig_sub) 485 return false; // One of dom's inputs dominated by sub. 486 if (!n->is_CFG() && n->pinned()) { 487 // Check only own control edge for pinned non-control nodes. 488 n = n->find_exact_control(n->in(0)); 489 if (n == NULL || n->is_top()) 490 return false; // Conservative answer for dead code 491 assert(n->is_CFG(), "expecting control"); 492 dom_list.push(n); 493 } else if (n->is_Con() || n->is_Start() || n->is_Root()) { 494 only_dominating_controls = true; 495 } else if (n->is_CFG()) { 496 if (n->dominates(sub, nlist)) 497 only_dominating_controls = true; 498 else 499 return false; 500 } else { 501 // First, own control edge. 502 Node* m = n->find_exact_control(n->in(0)); 503 if (m != NULL) { 504 if (m->is_top()) 505 return false; // Conservative answer for dead code 506 dom_list.push(m); 507 } 508 // Now, the rest of edges. 509 uint cnt = n->req(); 510 for (uint i = 1; i < cnt; i++) { 511 m = n->find_exact_control(n->in(i)); 512 if (m == NULL || m->is_top()) 513 continue; 514 dom_list.push(m); 515 } 516 } 517 } 518 return only_dominating_controls; 519 } 520 } 521 522 //---------------------detect_ptr_independence--------------------------------- 523 // Used by MemNode::find_previous_store to prove that two base 524 // pointers are never equal. 525 // The pointers are accompanied by their associated allocations, 526 // if any, which have been previously discovered by the caller. 527 bool MemNode::detect_ptr_independence(Node* p1, AllocateNode* a1, 528 Node* p2, AllocateNode* a2, 529 PhaseTransform* phase) { 530 // Attempt to prove that these two pointers cannot be aliased. 531 // They may both manifestly be allocations, and they should differ. 532 // Or, if they are not both allocations, they can be distinct constants. 533 // Otherwise, one is an allocation and the other a pre-existing value. 534 if (a1 == NULL && a2 == NULL) { // neither an allocation 535 return (p1 != p2) && p1->is_Con() && p2->is_Con(); 536 } else if (a1 != NULL && a2 != NULL) { // both allocations 537 return (a1 != a2); 538 } else if (a1 != NULL) { // one allocation a1 539 // (Note: p2->is_Con implies p2->in(0)->is_Root, which dominates.) 540 return all_controls_dominate(p2, a1); 541 } else { //(a2 != NULL) // one allocation a2 542 return all_controls_dominate(p1, a2); 543 } 544 return false; 545 } 546 547 548 // Find an arraycopy ac that produces the memory state represented by parameter mem. 549 // Return ac if 550 // (a) can_see_stored_value=true and ac must have set the value for this load or if 551 // (b) can_see_stored_value=false and ac could have set the value for this load or if 552 // (c) can_see_stored_value=false and ac cannot have set the value for this load. 553 // In case (c) change the parameter mem to the memory input of ac to skip it 554 // when searching stored value. 555 // Otherwise return NULL. 556 Node* LoadNode::find_previous_arraycopy(PhaseTransform* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const { 557 ArrayCopyNode* ac = find_array_copy_clone(phase, ld_alloc, mem); 558 if (ac != NULL) { 559 Node* ld_addp = in(MemNode::Address); 560 Node* src = ac->in(ArrayCopyNode::Src); 561 const TypeAryPtr* ary_t = phase->type(src)->isa_aryptr(); 562 563 // This is a load from a cloned array. The corresponding arraycopy ac must 564 // have set the value for the load and we can return ac but only if the load 565 // is known to be within bounds. This is checked below. 566 if (ary_t != NULL && ld_addp->is_AddP()) { 567 Node* ld_offs = ld_addp->in(AddPNode::Offset); 568 BasicType ary_elem = ary_t->elem()->array_element_basic_type(); 569 jlong header = arrayOopDesc::base_offset_in_bytes(ary_elem); 570 jlong elemsize = type2aelembytes(ary_elem); 571 572 const TypeX* ld_offs_t = phase->type(ld_offs)->isa_intptr_t(); 573 const TypeInt* sizetype = ary_t->size(); 574 575 if (ld_offs_t->_lo >= header && ld_offs_t->_hi < (sizetype->_lo * elemsize + header)) { 576 // The load is known to be within bounds. It receives its value from ac. 577 return ac; 578 } 579 // The load is known to be out-of-bounds. 580 } 581 // The load could be out-of-bounds. It must not be hoisted but must remain 582 // dependent on the runtime range check. This is achieved by returning NULL. 583 } else if (mem->is_Proj() && mem->in(0) != NULL && mem->in(0)->is_ArrayCopy()) { 584 ArrayCopyNode* ac = mem->in(0)->as_ArrayCopy(); 585 586 if (ac->is_arraycopy_validated() || 587 ac->is_copyof_validated() || 588 ac->is_copyofrange_validated()) { 589 Node* ld_addp = in(MemNode::Address); 590 if (ld_addp->is_AddP()) { 591 Node* ld_base = ld_addp->in(AddPNode::Address); 592 Node* ld_offs = ld_addp->in(AddPNode::Offset); 593 594 Node* dest = ac->in(ArrayCopyNode::Dest); 595 596 if (dest == ld_base) { 597 const TypeX *ld_offs_t = phase->type(ld_offs)->isa_intptr_t(); 598 if (ac->modifies(ld_offs_t->_lo, ld_offs_t->_hi, phase, can_see_stored_value)) { 599 return ac; 600 } 601 if (!can_see_stored_value) { 602 mem = ac->in(TypeFunc::Memory); 603 return ac; 604 } 605 } 606 } 607 } 608 } 609 return NULL; 610 } 611 612 ArrayCopyNode* MemNode::find_array_copy_clone(PhaseTransform* phase, Node* ld_alloc, Node* mem) const { 613 if (mem->is_Proj() && mem->in(0) != NULL && (mem->in(0)->Opcode() == Op_MemBarStoreStore || 614 mem->in(0)->Opcode() == Op_MemBarCPUOrder)) { 615 if (ld_alloc != NULL) { 616 // Check if there is an array copy for a clone 617 Node* mb = mem->in(0); 618 ArrayCopyNode* ac = NULL; 619 if (mb->in(0) != NULL && mb->in(0)->is_Proj() && 620 mb->in(0)->in(0) != NULL && mb->in(0)->in(0)->is_ArrayCopy()) { 621 ac = mb->in(0)->in(0)->as_ArrayCopy(); 622 } else { 623 // Step over GC barrier when ReduceInitialCardMarks is disabled 624 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2(); 625 Node* control_proj_ac = bs->step_over_gc_barrier(mb->in(0)); 626 627 if (control_proj_ac->is_Proj() && control_proj_ac->in(0)->is_ArrayCopy()) { 628 ac = control_proj_ac->in(0)->as_ArrayCopy(); 629 } 630 } 631 632 if (ac != NULL && ac->is_clonebasic()) { 633 AllocateNode* alloc = AllocateNode::Ideal_allocation(ac->in(ArrayCopyNode::Dest), phase); 634 if (alloc != NULL && alloc == ld_alloc) { 635 return ac; 636 } 637 } 638 } 639 } 640 return NULL; 641 } 642 643 // The logic for reordering loads and stores uses four steps: 644 // (a) Walk carefully past stores and initializations which we 645 // can prove are independent of this load. 646 // (b) Observe that the next memory state makes an exact match 647 // with self (load or store), and locate the relevant store. 648 // (c) Ensure that, if we were to wire self directly to the store, 649 // the optimizer would fold it up somehow. 650 // (d) Do the rewiring, and return, depending on some other part of 651 // the optimizer to fold up the load. 652 // This routine handles steps (a) and (b). Steps (c) and (d) are 653 // specific to loads and stores, so they are handled by the callers. 654 // (Currently, only LoadNode::Ideal has steps (c), (d). More later.) 655 // 656 Node* MemNode::find_previous_store(PhaseTransform* phase) { 657 Node* ctrl = in(MemNode::Control); 658 Node* adr = in(MemNode::Address); 659 intptr_t offset = 0; 660 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset); 661 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase); 662 663 if (offset == Type::OffsetBot) 664 return NULL; // cannot unalias unless there are precise offsets 665 666 const bool adr_maybe_raw = check_if_adr_maybe_raw(adr); 667 const TypeOopPtr *addr_t = adr->bottom_type()->isa_oopptr(); 668 669 intptr_t size_in_bytes = memory_size(); 670 671 Node* mem = in(MemNode::Memory); // start searching here... 672 673 int cnt = 50; // Cycle limiter 674 for (;;) { // While we can dance past unrelated stores... 675 if (--cnt < 0) break; // Caught in cycle or a complicated dance? 676 677 Node* prev = mem; 678 if (mem->is_Store()) { 679 Node* st_adr = mem->in(MemNode::Address); 680 intptr_t st_offset = 0; 681 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset); 682 if (st_base == NULL) 683 break; // inscrutable pointer 684 685 // For raw accesses it's not enough to prove that constant offsets don't intersect. 686 // We need the bases to be the equal in order for the offset check to make sense. 687 if ((adr_maybe_raw || check_if_adr_maybe_raw(st_adr)) && st_base != base) { 688 break; 689 } 690 691 if (st_offset != offset && st_offset != Type::OffsetBot) { 692 const int MAX_STORE = MAX2(BytesPerLong, (int)MaxVectorSize); 693 assert(mem->as_Store()->memory_size() <= MAX_STORE, ""); 694 if (st_offset >= offset + size_in_bytes || 695 st_offset <= offset - MAX_STORE || 696 st_offset <= offset - mem->as_Store()->memory_size()) { 697 // Success: The offsets are provably independent. 698 // (You may ask, why not just test st_offset != offset and be done? 699 // The answer is that stores of different sizes can co-exist 700 // in the same sequence of RawMem effects. We sometimes initialize 701 // a whole 'tile' of array elements with a single jint or jlong.) 702 mem = mem->in(MemNode::Memory); 703 continue; // (a) advance through independent store memory 704 } 705 } 706 if (st_base != base && 707 detect_ptr_independence(base, alloc, 708 st_base, 709 AllocateNode::Ideal_allocation(st_base, phase), 710 phase)) { 711 // Success: The bases are provably independent. 712 mem = mem->in(MemNode::Memory); 713 continue; // (a) advance through independent store memory 714 } 715 716 // (b) At this point, if the bases or offsets do not agree, we lose, 717 // since we have not managed to prove 'this' and 'mem' independent. 718 if (st_base == base && st_offset == offset) { 719 return mem; // let caller handle steps (c), (d) 720 } 721 722 } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) { 723 InitializeNode* st_init = mem->in(0)->as_Initialize(); 724 AllocateNode* st_alloc = st_init->allocation(); 725 if (st_alloc == NULL) 726 break; // something degenerated 727 bool known_identical = false; 728 bool known_independent = false; 729 if (alloc == st_alloc) 730 known_identical = true; 731 else if (alloc != NULL) 732 known_independent = true; 733 else if (all_controls_dominate(this, st_alloc)) 734 known_independent = true; 735 736 if (known_independent) { 737 // The bases are provably independent: Either they are 738 // manifestly distinct allocations, or else the control 739 // of this load dominates the store's allocation. 740 int alias_idx = phase->C->get_alias_index(adr_type()); 741 if (alias_idx == Compile::AliasIdxRaw) { 742 mem = st_alloc->in(TypeFunc::Memory); 743 } else { 744 mem = st_init->memory(alias_idx); 745 } 746 continue; // (a) advance through independent store memory 747 } 748 749 // (b) at this point, if we are not looking at a store initializing 750 // the same allocation we are loading from, we lose. 751 if (known_identical) { 752 // From caller, can_see_stored_value will consult find_captured_store. 753 return mem; // let caller handle steps (c), (d) 754 } 755 756 } else if (find_previous_arraycopy(phase, alloc, mem, false) != NULL) { 757 if (prev != mem) { 758 // Found an arraycopy but it doesn't affect that load 759 continue; 760 } 761 // Found an arraycopy that may affect that load 762 return mem; 763 } else if (addr_t != NULL && addr_t->is_known_instance_field()) { 764 // Can't use optimize_simple_memory_chain() since it needs PhaseGVN. 765 if (mem->is_Proj() && mem->in(0)->is_Call()) { 766 // ArrayCopyNodes processed here as well. 767 CallNode *call = mem->in(0)->as_Call(); 768 if (!call->may_modify(addr_t, phase)) { 769 mem = call->in(TypeFunc::Memory); 770 continue; // (a) advance through independent call memory 771 } 772 } else if (mem->is_Proj() && mem->in(0)->is_MemBar()) { 773 ArrayCopyNode* ac = NULL; 774 if (ArrayCopyNode::may_modify(addr_t, mem->in(0)->as_MemBar(), phase, ac)) { 775 break; 776 } 777 mem = mem->in(0)->in(TypeFunc::Memory); 778 continue; // (a) advance through independent MemBar memory 779 } else if (mem->is_ClearArray()) { 780 if (ClearArrayNode::step_through(&mem, (uint)addr_t->instance_id(), phase)) { 781 // (the call updated 'mem' value) 782 continue; // (a) advance through independent allocation memory 783 } else { 784 // Can not bypass initialization of the instance 785 // we are looking for. 786 return mem; 787 } 788 } else if (mem->is_MergeMem()) { 789 int alias_idx = phase->C->get_alias_index(adr_type()); 790 mem = mem->as_MergeMem()->memory_at(alias_idx); 791 continue; // (a) advance through independent MergeMem memory 792 } 793 } 794 795 // Unless there is an explicit 'continue', we must bail out here, 796 // because 'mem' is an inscrutable memory state (e.g., a call). 797 break; 798 } 799 800 return NULL; // bail out 801 } 802 803 //----------------------calculate_adr_type------------------------------------- 804 // Helper function. Notices when the given type of address hits top or bottom. 805 // Also, asserts a cross-check of the type against the expected address type. 806 const TypePtr* MemNode::calculate_adr_type(const Type* t, const TypePtr* cross_check) { 807 if (t == Type::TOP) return NULL; // does not touch memory any more? 808 #ifdef ASSERT 809 if (!VerifyAliases || VMError::is_error_reported() || Node::in_dump()) cross_check = NULL; 810 #endif 811 const TypePtr* tp = t->isa_ptr(); 812 if (tp == NULL) { 813 assert(cross_check == NULL || cross_check == TypePtr::BOTTOM, "expected memory type must be wide"); 814 return TypePtr::BOTTOM; // touches lots of memory 815 } else { 816 #ifdef ASSERT 817 // %%%% [phh] We don't check the alias index if cross_check is 818 // TypeRawPtr::BOTTOM. Needs to be investigated. 819 if (cross_check != NULL && 820 cross_check != TypePtr::BOTTOM && 821 cross_check != TypeRawPtr::BOTTOM) { 822 // Recheck the alias index, to see if it has changed (due to a bug). 823 Compile* C = Compile::current(); 824 assert(C->get_alias_index(cross_check) == C->get_alias_index(tp), 825 "must stay in the original alias category"); 826 // The type of the address must be contained in the adr_type, 827 // disregarding "null"-ness. 828 // (We make an exception for TypeRawPtr::BOTTOM, which is a bit bucket.) 829 const TypePtr* tp_notnull = tp->join(TypePtr::NOTNULL)->is_ptr(); 830 assert(cross_check->meet(tp_notnull) == cross_check->remove_speculative(), 831 "real address must not escape from expected memory type"); 832 } 833 #endif 834 return tp; 835 } 836 } 837 838 //============================================================================= 839 // Should LoadNode::Ideal() attempt to remove control edges? 840 bool LoadNode::can_remove_control() const { 841 return !has_pinned_control_dependency(); 842 } 843 uint LoadNode::size_of() const { return sizeof(*this); } 844 bool LoadNode::cmp( const Node &n ) const 845 { return !Type::cmp( _type, ((LoadNode&)n)._type ); } 846 const Type *LoadNode::bottom_type() const { return _type; } 847 uint LoadNode::ideal_reg() const { 848 return _type->ideal_reg(); 849 } 850 851 #ifndef PRODUCT 852 void LoadNode::dump_spec(outputStream *st) const { 853 MemNode::dump_spec(st); 854 if( !Verbose && !WizardMode ) { 855 // standard dump does this in Verbose and WizardMode 856 st->print(" #"); _type->dump_on(st); 857 } 858 if (!depends_only_on_test()) { 859 st->print(" (does not depend only on test, "); 860 if (control_dependency() == UnknownControl) { 861 st->print("unknown control"); 862 } else if (control_dependency() == Pinned) { 863 st->print("pinned"); 864 } else if (adr_type() == TypeRawPtr::BOTTOM) { 865 st->print("raw access"); 866 } else { 867 st->print("unknown reason"); 868 } 869 st->print(")"); 870 } 871 } 872 #endif 873 874 #ifdef ASSERT 875 //----------------------------is_immutable_value------------------------------- 876 // Helper function to allow a raw load without control edge for some cases 877 bool LoadNode::is_immutable_value(Node* adr) { 878 if (adr->is_AddP() && adr->in(AddPNode::Base)->is_top() && 879 adr->in(AddPNode::Address)->Opcode() == Op_ThreadLocal) { 880 881 jlong offset = adr->in(AddPNode::Offset)->find_intptr_t_con(-1); 882 int offsets[] = { 883 in_bytes(JavaThread::osthread_offset()), 884 in_bytes(JavaThread::threadObj_offset()), 885 in_bytes(JavaThread::vthread_offset()), 886 in_bytes(JavaThread::scopedValueCache_offset()), 887 }; 888 889 for (size_t i = 0; i < sizeof offsets / sizeof offsets[0]; i++) { 890 if (offset == offsets[i]) { 891 return true; 892 } 893 } 894 } 895 896 return false; 897 } 898 #endif 899 900 //----------------------------LoadNode::make----------------------------------- 901 // Polymorphic factory method: 902 Node* LoadNode::make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, const Type* rt, BasicType bt, MemOrd mo, 903 ControlDependency control_dependency, bool require_atomic_access, bool unaligned, bool mismatched, bool unsafe, uint8_t barrier_data) { 904 Compile* C = gvn.C; 905 906 // sanity check the alias category against the created node type 907 assert(!(adr_type->isa_oopptr() && 908 adr_type->offset() == oopDesc::klass_offset_in_bytes()), 909 "use LoadKlassNode instead"); 910 assert(!(adr_type->isa_aryptr() && 911 adr_type->offset() == arrayOopDesc::length_offset_in_bytes()), 912 "use LoadRangeNode instead"); 913 // Check control edge of raw loads 914 assert( ctl != NULL || C->get_alias_index(adr_type) != Compile::AliasIdxRaw || 915 // oop will be recorded in oop map if load crosses safepoint 916 rt->isa_oopptr() || is_immutable_value(adr), 917 "raw memory operations should have control edge"); 918 LoadNode* load = NULL; 919 switch (bt) { 920 case T_BOOLEAN: load = new LoadUBNode(ctl, mem, adr, adr_type, rt->is_int(), mo, control_dependency); break; 921 case T_BYTE: load = new LoadBNode (ctl, mem, adr, adr_type, rt->is_int(), mo, control_dependency); break; 922 case T_INT: load = new LoadINode (ctl, mem, adr, adr_type, rt->is_int(), mo, control_dependency); break; 923 case T_CHAR: load = new LoadUSNode(ctl, mem, adr, adr_type, rt->is_int(), mo, control_dependency); break; 924 case T_SHORT: load = new LoadSNode (ctl, mem, adr, adr_type, rt->is_int(), mo, control_dependency); break; 925 case T_LONG: load = new LoadLNode (ctl, mem, adr, adr_type, rt->is_long(), mo, control_dependency, require_atomic_access); break; 926 case T_FLOAT: load = new LoadFNode (ctl, mem, adr, adr_type, rt, mo, control_dependency); break; 927 case T_DOUBLE: load = new LoadDNode (ctl, mem, adr, adr_type, rt, mo, control_dependency, require_atomic_access); break; 928 case T_ADDRESS: load = new LoadPNode (ctl, mem, adr, adr_type, rt->is_ptr(), mo, control_dependency); break; 929 case T_PRIMITIVE_OBJECT: 930 case T_OBJECT: 931 #ifdef _LP64 932 if (adr->bottom_type()->is_ptr_to_narrowoop()) { 933 load = new LoadNNode(ctl, mem, adr, adr_type, rt->make_narrowoop(), mo, control_dependency); 934 } else 935 #endif 936 { 937 assert(!adr->bottom_type()->is_ptr_to_narrowoop() && !adr->bottom_type()->is_ptr_to_narrowklass(), "should have got back a narrow oop"); 938 load = new LoadPNode(ctl, mem, adr, adr_type, rt->is_ptr(), mo, control_dependency); 939 } 940 break; 941 default: 942 ShouldNotReachHere(); 943 break; 944 } 945 assert(load != NULL, "LoadNode should have been created"); 946 if (unaligned) { 947 load->set_unaligned_access(); 948 } 949 if (mismatched) { 950 load->set_mismatched_access(); 951 } 952 if (unsafe) { 953 load->set_unsafe_access(); 954 } 955 load->set_barrier_data(barrier_data); 956 if (load->Opcode() == Op_LoadN) { 957 Node* ld = gvn.transform(load); 958 return new DecodeNNode(ld, ld->bottom_type()->make_ptr()); 959 } 960 961 return load; 962 } 963 964 //------------------------------hash------------------------------------------- 965 uint LoadNode::hash() const { 966 // unroll addition of interesting fields 967 return (uintptr_t)in(Control) + (uintptr_t)in(Memory) + (uintptr_t)in(Address); 968 } 969 970 static bool skip_through_membars(Compile::AliasType* atp, const TypeInstPtr* tp, bool eliminate_boxing) { 971 if ((atp != NULL) && (atp->index() >= Compile::AliasIdxRaw)) { 972 bool non_volatile = (atp->field() != NULL) && !atp->field()->is_volatile(); 973 bool is_stable_ary = FoldStableValues && 974 (tp != NULL) && (tp->isa_aryptr() != NULL) && 975 tp->isa_aryptr()->is_stable(); 976 977 return (eliminate_boxing && non_volatile) || is_stable_ary; 978 } 979 980 return false; 981 } 982 983 // Is the value loaded previously stored by an arraycopy? If so return 984 // a load node that reads from the source array so we may be able to 985 // optimize out the ArrayCopy node later. 986 Node* LoadNode::can_see_arraycopy_value(Node* st, PhaseGVN* phase) const { 987 Node* ld_adr = in(MemNode::Address); 988 intptr_t ld_off = 0; 989 AllocateNode* ld_alloc = AllocateNode::Ideal_allocation(ld_adr, phase, ld_off); 990 Node* ac = find_previous_arraycopy(phase, ld_alloc, st, true); 991 if (ac != NULL) { 992 assert(ac->is_ArrayCopy(), "what kind of node can this be?"); 993 994 Node* mem = ac->in(TypeFunc::Memory); 995 Node* ctl = ac->in(0); 996 Node* src = ac->in(ArrayCopyNode::Src); 997 998 if (!ac->as_ArrayCopy()->is_clonebasic() && !phase->type(src)->isa_aryptr()) { 999 return NULL; 1000 } 1001 1002 LoadNode* ld = clone()->as_Load(); 1003 Node* addp = in(MemNode::Address)->clone(); 1004 if (ac->as_ArrayCopy()->is_clonebasic()) { 1005 assert(ld_alloc != NULL, "need an alloc"); 1006 assert(addp->is_AddP(), "address must be addp"); 1007 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2(); 1008 assert(bs->step_over_gc_barrier(addp->in(AddPNode::Base)) == bs->step_over_gc_barrier(ac->in(ArrayCopyNode::Dest)), "strange pattern"); 1009 assert(bs->step_over_gc_barrier(addp->in(AddPNode::Address)) == bs->step_over_gc_barrier(ac->in(ArrayCopyNode::Dest)), "strange pattern"); 1010 addp->set_req(AddPNode::Base, src); 1011 addp->set_req(AddPNode::Address, src); 1012 } else { 1013 assert(ac->as_ArrayCopy()->is_arraycopy_validated() || 1014 ac->as_ArrayCopy()->is_copyof_validated() || 1015 ac->as_ArrayCopy()->is_copyofrange_validated(), "only supported cases"); 1016 assert(addp->in(AddPNode::Base) == addp->in(AddPNode::Address), "should be"); 1017 addp->set_req(AddPNode::Base, src); 1018 addp->set_req(AddPNode::Address, src); 1019 1020 const TypeAryPtr* ary_t = phase->type(in(MemNode::Address))->isa_aryptr(); 1021 BasicType ary_elem = ary_t->isa_aryptr()->elem()->array_element_basic_type(); 1022 if (is_reference_type(ary_elem, true)) ary_elem = T_OBJECT; 1023 1024 uint header = arrayOopDesc::base_offset_in_bytes(ary_elem); 1025 uint shift = ary_t->is_flat() ? ary_t->flat_log_elem_size() : exact_log2(type2aelembytes(ary_elem)); 1026 1027 Node* diff = phase->transform(new SubINode(ac->in(ArrayCopyNode::SrcPos), ac->in(ArrayCopyNode::DestPos))); 1028 #ifdef _LP64 1029 diff = phase->transform(new ConvI2LNode(diff)); 1030 #endif 1031 diff = phase->transform(new LShiftXNode(diff, phase->intcon(shift))); 1032 1033 Node* offset = phase->transform(new AddXNode(addp->in(AddPNode::Offset), diff)); 1034 addp->set_req(AddPNode::Offset, offset); 1035 } 1036 addp = phase->transform(addp); 1037 #ifdef ASSERT 1038 const TypePtr* adr_type = phase->type(addp)->is_ptr(); 1039 ld->_adr_type = adr_type; 1040 #endif 1041 ld->set_req(MemNode::Address, addp); 1042 ld->set_req(0, ctl); 1043 ld->set_req(MemNode::Memory, mem); 1044 // load depends on the tests that validate the arraycopy 1045 ld->_control_dependency = UnknownControl; 1046 return ld; 1047 } 1048 return NULL; 1049 } 1050 1051 1052 //---------------------------can_see_stored_value------------------------------ 1053 // This routine exists to make sure this set of tests is done the same 1054 // everywhere. We need to make a coordinated change: first LoadNode::Ideal 1055 // will change the graph shape in a way which makes memory alive twice at the 1056 // same time (uses the Oracle model of aliasing), then some 1057 // LoadXNode::Identity will fold things back to the equivalence-class model 1058 // of aliasing. 1059 Node* MemNode::can_see_stored_value(Node* st, PhaseTransform* phase) const { 1060 Node* ld_adr = in(MemNode::Address); 1061 intptr_t ld_off = 0; 1062 Node* ld_base = AddPNode::Ideal_base_and_offset(ld_adr, phase, ld_off); 1063 Node* ld_alloc = AllocateNode::Ideal_allocation(ld_base, phase); 1064 const TypeInstPtr* tp = phase->type(ld_adr)->isa_instptr(); 1065 Compile::AliasType* atp = (tp != NULL) ? phase->C->alias_type(tp) : NULL; 1066 // This is more general than load from boxing objects. 1067 if (skip_through_membars(atp, tp, phase->C->eliminate_boxing())) { 1068 uint alias_idx = atp->index(); 1069 Node* result = NULL; 1070 Node* current = st; 1071 // Skip through chains of MemBarNodes checking the MergeMems for 1072 // new states for the slice of this load. Stop once any other 1073 // kind of node is encountered. Loads from final memory can skip 1074 // through any kind of MemBar but normal loads shouldn't skip 1075 // through MemBarAcquire since the could allow them to move out of 1076 // a synchronized region. It is not safe to step over MemBarCPUOrder, 1077 // because alias info above them may be inaccurate (e.g., due to 1078 // mixed/mismatched unsafe accesses). 1079 bool is_final_mem = !atp->is_rewritable(); 1080 while (current->is_Proj()) { 1081 int opc = current->in(0)->Opcode(); 1082 if ((is_final_mem && (opc == Op_MemBarAcquire || 1083 opc == Op_MemBarAcquireLock || 1084 opc == Op_LoadFence)) || 1085 opc == Op_MemBarRelease || 1086 opc == Op_StoreFence || 1087 opc == Op_MemBarReleaseLock || 1088 opc == Op_MemBarStoreStore || 1089 opc == Op_StoreStoreFence) { 1090 Node* mem = current->in(0)->in(TypeFunc::Memory); 1091 if (mem->is_MergeMem()) { 1092 MergeMemNode* merge = mem->as_MergeMem(); 1093 Node* new_st = merge->memory_at(alias_idx); 1094 if (new_st == merge->base_memory()) { 1095 // Keep searching 1096 current = new_st; 1097 continue; 1098 } 1099 // Save the new memory state for the slice and fall through 1100 // to exit. 1101 result = new_st; 1102 } 1103 } 1104 break; 1105 } 1106 if (result != NULL) { 1107 st = result; 1108 } 1109 } 1110 1111 // Loop around twice in the case Load -> Initialize -> Store. 1112 // (See PhaseIterGVN::add_users_to_worklist, which knows about this case.) 1113 for (int trip = 0; trip <= 1; trip++) { 1114 1115 if (st->is_Store()) { 1116 Node* st_adr = st->in(MemNode::Address); 1117 if (st_adr != ld_adr) { 1118 // Try harder before giving up. Unify base pointers with casts (e.g., raw/non-raw pointers). 1119 intptr_t st_off = 0; 1120 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_off); 1121 if (ld_base == NULL) return NULL; 1122 if (st_base == NULL) return NULL; 1123 if (!ld_base->eqv_uncast(st_base, /*keep_deps=*/true)) return NULL; 1124 if (ld_off != st_off) return NULL; 1125 if (ld_off == Type::OffsetBot) return NULL; 1126 // Same base, same offset. 1127 // Possible improvement for arrays: check index value instead of absolute offset. 1128 1129 // At this point we have proven something like this setup: 1130 // B = << base >> 1131 // L = LoadQ(AddP(Check/CastPP(B), #Off)) 1132 // S = StoreQ(AddP( B , #Off), V) 1133 // (Actually, we haven't yet proven the Q's are the same.) 1134 // In other words, we are loading from a casted version of 1135 // the same pointer-and-offset that we stored to. 1136 // Casted version may carry a dependency and it is respected. 1137 // Thus, we are able to replace L by V. 1138 } 1139 // Now prove that we have a LoadQ matched to a StoreQ, for some Q. 1140 if (store_Opcode() != st->Opcode()) { 1141 return NULL; 1142 } 1143 // LoadVector/StoreVector needs additional check to ensure the types match. 1144 if (st->is_StoreVector()) { 1145 const TypeVect* in_vt = st->as_StoreVector()->vect_type(); 1146 const TypeVect* out_vt = is_Load() ? as_LoadVector()->vect_type() : as_StoreVector()->vect_type(); 1147 if (in_vt != out_vt) { 1148 return NULL; 1149 } 1150 } 1151 return st->in(MemNode::ValueIn); 1152 } 1153 1154 // A load from a freshly-created object always returns zero. 1155 // (This can happen after LoadNode::Ideal resets the load's memory input 1156 // to find_captured_store, which returned InitializeNode::zero_memory.) 1157 if (st->is_Proj() && st->in(0)->is_Allocate() && 1158 (st->in(0) == ld_alloc) && 1159 (ld_off >= st->in(0)->as_Allocate()->minimum_header_size())) { 1160 // return a zero value for the load's basic type 1161 // (This is one of the few places where a generic PhaseTransform 1162 // can create new nodes. Think of it as lazily manifesting 1163 // virtually pre-existing constants.) 1164 assert(memory_type() != T_PRIMITIVE_OBJECT, "should not be used for inline types"); 1165 Node* default_value = ld_alloc->in(AllocateNode::DefaultValue); 1166 if (default_value != NULL) { 1167 return default_value; 1168 } 1169 assert(ld_alloc->in(AllocateNode::RawDefaultValue) == NULL, "default value may not be null"); 1170 if (memory_type() != T_VOID) { 1171 if (ReduceBulkZeroing || find_array_copy_clone(phase, ld_alloc, in(MemNode::Memory)) == NULL) { 1172 // If ReduceBulkZeroing is disabled, we need to check if the allocation does not belong to an 1173 // ArrayCopyNode clone. If it does, then we cannot assume zero since the initialization is done 1174 // by the ArrayCopyNode. 1175 return phase->zerocon(memory_type()); 1176 } 1177 } else { 1178 // TODO: materialize all-zero vector constant 1179 assert(!isa_Load() || as_Load()->type()->isa_vect(), ""); 1180 } 1181 } 1182 1183 // A load from an initialization barrier can match a captured store. 1184 if (st->is_Proj() && st->in(0)->is_Initialize()) { 1185 InitializeNode* init = st->in(0)->as_Initialize(); 1186 AllocateNode* alloc = init->allocation(); 1187 if ((alloc != NULL) && (alloc == ld_alloc)) { 1188 // examine a captured store value 1189 st = init->find_captured_store(ld_off, memory_size(), phase); 1190 if (st != NULL) { 1191 continue; // take one more trip around 1192 } 1193 } 1194 } 1195 1196 // Load boxed value from result of valueOf() call is input parameter. 1197 if (this->is_Load() && ld_adr->is_AddP() && 1198 (tp != NULL) && tp->is_ptr_to_boxed_value()) { 1199 intptr_t ignore = 0; 1200 Node* base = AddPNode::Ideal_base_and_offset(ld_adr, phase, ignore); 1201 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2(); 1202 base = bs->step_over_gc_barrier(base); 1203 if (base != NULL && base->is_Proj() && 1204 base->as_Proj()->_con == TypeFunc::Parms && 1205 base->in(0)->is_CallStaticJava() && 1206 base->in(0)->as_CallStaticJava()->is_boxing_method()) { 1207 return base->in(0)->in(TypeFunc::Parms); 1208 } 1209 } 1210 1211 break; 1212 } 1213 1214 return NULL; 1215 } 1216 1217 //----------------------is_instance_field_load_with_local_phi------------------ 1218 bool LoadNode::is_instance_field_load_with_local_phi(Node* ctrl) { 1219 if( in(Memory)->is_Phi() && in(Memory)->in(0) == ctrl && 1220 in(Address)->is_AddP() ) { 1221 const TypeOopPtr* t_oop = in(Address)->bottom_type()->isa_oopptr(); 1222 // Only instances and boxed values. 1223 if( t_oop != NULL && 1224 (t_oop->is_ptr_to_boxed_value() || 1225 t_oop->is_known_instance_field()) && 1226 t_oop->offset() != Type::OffsetBot && 1227 t_oop->offset() != Type::OffsetTop) { 1228 return true; 1229 } 1230 } 1231 return false; 1232 } 1233 1234 //------------------------------Identity--------------------------------------- 1235 // Loads are identity if previous store is to same address 1236 Node* LoadNode::Identity(PhaseGVN* phase) { 1237 // Loading from an InlineType? The InlineType has the values of 1238 // all fields as input. Look for the field with matching offset. 1239 Node* addr = in(Address); 1240 intptr_t offset; 1241 Node* base = AddPNode::Ideal_base_and_offset(addr, phase, offset); 1242 if (base != NULL && base->is_InlineType() && offset > oopDesc::klass_offset_in_bytes()) { 1243 Node* value = base->as_InlineType()->field_value_by_offset((int)offset, true); 1244 if (value != NULL) { 1245 if (Opcode() == Op_LoadN) { 1246 // Encode oop value if we are loading a narrow oop 1247 assert(!phase->type(value)->isa_narrowoop(), "should already be decoded"); 1248 value = phase->transform(new EncodePNode(value, bottom_type())); 1249 } 1250 return value; 1251 } 1252 } 1253 1254 // If the previous store-maker is the right kind of Store, and the store is 1255 // to the same address, then we are equal to the value stored. 1256 Node* mem = in(Memory); 1257 Node* value = can_see_stored_value(mem, phase); 1258 if( value ) { 1259 // byte, short & char stores truncate naturally. 1260 // A load has to load the truncated value which requires 1261 // some sort of masking operation and that requires an 1262 // Ideal call instead of an Identity call. 1263 if (memory_size() < BytesPerInt) { 1264 // If the input to the store does not fit with the load's result type, 1265 // it must be truncated via an Ideal call. 1266 if (!phase->type(value)->higher_equal(phase->type(this))) 1267 return this; 1268 } 1269 // (This works even when value is a Con, but LoadNode::Value 1270 // usually runs first, producing the singleton type of the Con.) 1271 if (!has_pinned_control_dependency() || value->is_Con()) { 1272 return value; 1273 } else { 1274 return this; 1275 } 1276 } 1277 1278 if (has_pinned_control_dependency()) { 1279 return this; 1280 } 1281 // Search for an existing data phi which was generated before for the same 1282 // instance's field to avoid infinite generation of phis in a loop. 1283 Node *region = mem->in(0); 1284 if (is_instance_field_load_with_local_phi(region)) { 1285 const TypeOopPtr *addr_t = in(Address)->bottom_type()->isa_oopptr(); 1286 int this_index = phase->C->get_alias_index(addr_t); 1287 int this_offset = addr_t->offset(); 1288 int this_iid = addr_t->instance_id(); 1289 if (!addr_t->is_known_instance() && 1290 addr_t->is_ptr_to_boxed_value()) { 1291 // Use _idx of address base (could be Phi node) for boxed values. 1292 intptr_t ignore = 0; 1293 Node* base = AddPNode::Ideal_base_and_offset(in(Address), phase, ignore); 1294 if (base == NULL) { 1295 return this; 1296 } 1297 this_iid = base->_idx; 1298 } 1299 const Type* this_type = bottom_type(); 1300 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { 1301 Node* phi = region->fast_out(i); 1302 if (phi->is_Phi() && phi != mem && 1303 phi->as_Phi()->is_same_inst_field(this_type, (int)mem->_idx, this_iid, this_index, this_offset)) { 1304 return phi; 1305 } 1306 } 1307 } 1308 1309 return this; 1310 } 1311 1312 // Construct an equivalent unsigned load. 1313 Node* LoadNode::convert_to_unsigned_load(PhaseGVN& gvn) { 1314 BasicType bt = T_ILLEGAL; 1315 const Type* rt = NULL; 1316 switch (Opcode()) { 1317 case Op_LoadUB: return this; 1318 case Op_LoadUS: return this; 1319 case Op_LoadB: bt = T_BOOLEAN; rt = TypeInt::UBYTE; break; 1320 case Op_LoadS: bt = T_CHAR; rt = TypeInt::CHAR; break; 1321 default: 1322 assert(false, "no unsigned variant: %s", Name()); 1323 return NULL; 1324 } 1325 return LoadNode::make(gvn, in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address), 1326 raw_adr_type(), rt, bt, _mo, _control_dependency, 1327 false /*require_atomic_access*/, is_unaligned_access(), is_mismatched_access()); 1328 } 1329 1330 // Construct an equivalent signed load. 1331 Node* LoadNode::convert_to_signed_load(PhaseGVN& gvn) { 1332 BasicType bt = T_ILLEGAL; 1333 const Type* rt = NULL; 1334 switch (Opcode()) { 1335 case Op_LoadUB: bt = T_BYTE; rt = TypeInt::BYTE; break; 1336 case Op_LoadUS: bt = T_SHORT; rt = TypeInt::SHORT; break; 1337 case Op_LoadB: // fall through 1338 case Op_LoadS: // fall through 1339 case Op_LoadI: // fall through 1340 case Op_LoadL: return this; 1341 default: 1342 assert(false, "no signed variant: %s", Name()); 1343 return NULL; 1344 } 1345 return LoadNode::make(gvn, in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address), 1346 raw_adr_type(), rt, bt, _mo, _control_dependency, 1347 false /*require_atomic_access*/, is_unaligned_access(), is_mismatched_access()); 1348 } 1349 1350 bool LoadNode::has_reinterpret_variant(const Type* rt) { 1351 BasicType bt = rt->basic_type(); 1352 switch (Opcode()) { 1353 case Op_LoadI: return (bt == T_FLOAT); 1354 case Op_LoadL: return (bt == T_DOUBLE); 1355 case Op_LoadF: return (bt == T_INT); 1356 case Op_LoadD: return (bt == T_LONG); 1357 1358 default: return false; 1359 } 1360 } 1361 1362 Node* LoadNode::convert_to_reinterpret_load(PhaseGVN& gvn, const Type* rt) { 1363 BasicType bt = rt->basic_type(); 1364 assert(has_reinterpret_variant(rt), "no reinterpret variant: %s %s", Name(), type2name(bt)); 1365 bool is_mismatched = is_mismatched_access(); 1366 const TypeRawPtr* raw_type = gvn.type(in(MemNode::Memory))->isa_rawptr(); 1367 if (raw_type == NULL) { 1368 is_mismatched = true; // conservatively match all non-raw accesses as mismatched 1369 } 1370 const int op = Opcode(); 1371 bool require_atomic_access = (op == Op_LoadL && ((LoadLNode*)this)->require_atomic_access()) || 1372 (op == Op_LoadD && ((LoadDNode*)this)->require_atomic_access()); 1373 return LoadNode::make(gvn, in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address), 1374 raw_adr_type(), rt, bt, _mo, _control_dependency, 1375 require_atomic_access, is_unaligned_access(), is_mismatched); 1376 } 1377 1378 bool StoreNode::has_reinterpret_variant(const Type* vt) { 1379 BasicType bt = vt->basic_type(); 1380 switch (Opcode()) { 1381 case Op_StoreI: return (bt == T_FLOAT); 1382 case Op_StoreL: return (bt == T_DOUBLE); 1383 case Op_StoreF: return (bt == T_INT); 1384 case Op_StoreD: return (bt == T_LONG); 1385 1386 default: return false; 1387 } 1388 } 1389 1390 Node* StoreNode::convert_to_reinterpret_store(PhaseGVN& gvn, Node* val, const Type* vt) { 1391 BasicType bt = vt->basic_type(); 1392 assert(has_reinterpret_variant(vt), "no reinterpret variant: %s %s", Name(), type2name(bt)); 1393 const int op = Opcode(); 1394 bool require_atomic_access = (op == Op_StoreL && ((StoreLNode*)this)->require_atomic_access()) || 1395 (op == Op_StoreD && ((StoreDNode*)this)->require_atomic_access()); 1396 StoreNode* st = StoreNode::make(gvn, in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address), 1397 raw_adr_type(), val, bt, _mo, require_atomic_access); 1398 1399 bool is_mismatched = is_mismatched_access(); 1400 const TypeRawPtr* raw_type = gvn.type(in(MemNode::Memory))->isa_rawptr(); 1401 if (raw_type == NULL) { 1402 is_mismatched = true; // conservatively match all non-raw accesses as mismatched 1403 } 1404 if (is_mismatched) { 1405 st->set_mismatched_access(); 1406 } 1407 return st; 1408 } 1409 1410 // We're loading from an object which has autobox behaviour. 1411 // If this object is result of a valueOf call we'll have a phi 1412 // merging a newly allocated object and a load from the cache. 1413 // We want to replace this load with the original incoming 1414 // argument to the valueOf call. 1415 Node* LoadNode::eliminate_autobox(PhaseIterGVN* igvn) { 1416 assert(igvn->C->eliminate_boxing(), "sanity"); 1417 intptr_t ignore = 0; 1418 Node* base = AddPNode::Ideal_base_and_offset(in(Address), igvn, ignore); 1419 if ((base == NULL) || base->is_Phi()) { 1420 // Push the loads from the phi that comes from valueOf up 1421 // through it to allow elimination of the loads and the recovery 1422 // of the original value. It is done in split_through_phi(). 1423 return NULL; 1424 } else if (base->is_Load() || 1425 (base->is_DecodeN() && base->in(1)->is_Load())) { 1426 // Eliminate the load of boxed value for integer types from the cache 1427 // array by deriving the value from the index into the array. 1428 // Capture the offset of the load and then reverse the computation. 1429 1430 // Get LoadN node which loads a boxing object from 'cache' array. 1431 if (base->is_DecodeN()) { 1432 base = base->in(1); 1433 } 1434 if (!base->in(Address)->is_AddP()) { 1435 return NULL; // Complex address 1436 } 1437 AddPNode* address = base->in(Address)->as_AddP(); 1438 Node* cache_base = address->in(AddPNode::Base); 1439 if ((cache_base != NULL) && cache_base->is_DecodeN()) { 1440 // Get ConP node which is static 'cache' field. 1441 cache_base = cache_base->in(1); 1442 } 1443 if ((cache_base != NULL) && cache_base->is_Con()) { 1444 const TypeAryPtr* base_type = cache_base->bottom_type()->isa_aryptr(); 1445 if ((base_type != NULL) && base_type->is_autobox_cache()) { 1446 Node* elements[4]; 1447 int shift = exact_log2(type2aelembytes(T_OBJECT)); 1448 int count = address->unpack_offsets(elements, ARRAY_SIZE(elements)); 1449 if (count > 0 && elements[0]->is_Con() && 1450 (count == 1 || 1451 (count == 2 && elements[1]->Opcode() == Op_LShiftX && 1452 elements[1]->in(2) == igvn->intcon(shift)))) { 1453 ciObjArray* array = base_type->const_oop()->as_obj_array(); 1454 // Fetch the box object cache[0] at the base of the array and get its value 1455 ciInstance* box = array->obj_at(0)->as_instance(); 1456 ciInstanceKlass* ik = box->klass()->as_instance_klass(); 1457 assert(ik->is_box_klass(), "sanity"); 1458 assert(ik->nof_nonstatic_fields() == 1, "change following code"); 1459 if (ik->nof_nonstatic_fields() == 1) { 1460 // This should be true nonstatic_field_at requires calling 1461 // nof_nonstatic_fields so check it anyway 1462 ciConstant c = box->field_value(ik->nonstatic_field_at(0)); 1463 BasicType bt = c.basic_type(); 1464 // Only integer types have boxing cache. 1465 assert(bt == T_BOOLEAN || bt == T_CHAR || 1466 bt == T_BYTE || bt == T_SHORT || 1467 bt == T_INT || bt == T_LONG, "wrong type = %s", type2name(bt)); 1468 jlong cache_low = (bt == T_LONG) ? c.as_long() : c.as_int(); 1469 if (cache_low != (int)cache_low) { 1470 return NULL; // should not happen since cache is array indexed by value 1471 } 1472 jlong offset = arrayOopDesc::base_offset_in_bytes(T_OBJECT) - (cache_low << shift); 1473 if (offset != (int)offset) { 1474 return NULL; // should not happen since cache is array indexed by value 1475 } 1476 // Add up all the offsets making of the address of the load 1477 Node* result = elements[0]; 1478 for (int i = 1; i < count; i++) { 1479 result = igvn->transform(new AddXNode(result, elements[i])); 1480 } 1481 // Remove the constant offset from the address and then 1482 result = igvn->transform(new AddXNode(result, igvn->MakeConX(-(int)offset))); 1483 // remove the scaling of the offset to recover the original index. 1484 if (result->Opcode() == Op_LShiftX && result->in(2) == igvn->intcon(shift)) { 1485 // Peel the shift off directly but wrap it in a dummy node 1486 // since Ideal can't return existing nodes 1487 igvn->_worklist.push(result); // remove dead node later 1488 result = new RShiftXNode(result->in(1), igvn->intcon(0)); 1489 } else if (result->is_Add() && result->in(2)->is_Con() && 1490 result->in(1)->Opcode() == Op_LShiftX && 1491 result->in(1)->in(2) == igvn->intcon(shift)) { 1492 // We can't do general optimization: ((X<<Z) + Y) >> Z ==> X + (Y>>Z) 1493 // but for boxing cache access we know that X<<Z will not overflow 1494 // (there is range check) so we do this optimizatrion by hand here. 1495 igvn->_worklist.push(result); // remove dead node later 1496 Node* add_con = new RShiftXNode(result->in(2), igvn->intcon(shift)); 1497 result = new AddXNode(result->in(1)->in(1), igvn->transform(add_con)); 1498 } else { 1499 result = new RShiftXNode(result, igvn->intcon(shift)); 1500 } 1501 #ifdef _LP64 1502 if (bt != T_LONG) { 1503 result = new ConvL2INode(igvn->transform(result)); 1504 } 1505 #else 1506 if (bt == T_LONG) { 1507 result = new ConvI2LNode(igvn->transform(result)); 1508 } 1509 #endif 1510 // Boxing/unboxing can be done from signed & unsigned loads (e.g. LoadUB -> ... -> LoadB pair). 1511 // Need to preserve unboxing load type if it is unsigned. 1512 switch(this->Opcode()) { 1513 case Op_LoadUB: 1514 result = new AndINode(igvn->transform(result), igvn->intcon(0xFF)); 1515 break; 1516 case Op_LoadUS: 1517 result = new AndINode(igvn->transform(result), igvn->intcon(0xFFFF)); 1518 break; 1519 } 1520 return result; 1521 } 1522 } 1523 } 1524 } 1525 } 1526 return NULL; 1527 } 1528 1529 static bool stable_phi(PhiNode* phi, PhaseGVN *phase) { 1530 Node* region = phi->in(0); 1531 if (region == NULL) { 1532 return false; // Wait stable graph 1533 } 1534 uint cnt = phi->req(); 1535 for (uint i = 1; i < cnt; i++) { 1536 Node* rc = region->in(i); 1537 if (rc == NULL || phase->type(rc) == Type::TOP) 1538 return false; // Wait stable graph 1539 Node* in = phi->in(i); 1540 if (in == NULL || phase->type(in) == Type::TOP) 1541 return false; // Wait stable graph 1542 } 1543 return true; 1544 } 1545 //------------------------------split_through_phi------------------------------ 1546 // Split instance or boxed field load through Phi. 1547 Node* LoadNode::split_through_phi(PhaseGVN* phase) { 1548 if (req() > 3) { 1549 assert(is_LoadVector() && Opcode() != Op_LoadVector, "load has too many inputs"); 1550 // LoadVector subclasses such as LoadVectorMasked have extra inputs that the logic below doesn't take into account 1551 return NULL; 1552 } 1553 Node* mem = in(Memory); 1554 Node* address = in(Address); 1555 const TypeOopPtr *t_oop = phase->type(address)->isa_oopptr(); 1556 1557 assert((t_oop != NULL) && 1558 (t_oop->is_known_instance_field() || 1559 t_oop->is_ptr_to_boxed_value()), "invalid conditions"); 1560 1561 Compile* C = phase->C; 1562 intptr_t ignore = 0; 1563 Node* base = AddPNode::Ideal_base_and_offset(address, phase, ignore); 1564 bool base_is_phi = (base != NULL) && base->is_Phi(); 1565 bool load_boxed_values = t_oop->is_ptr_to_boxed_value() && C->aggressive_unboxing() && 1566 (base != NULL) && (base == address->in(AddPNode::Base)) && 1567 phase->type(base)->higher_equal(TypePtr::NOTNULL); 1568 1569 if (!((mem->is_Phi() || base_is_phi) && 1570 (load_boxed_values || t_oop->is_known_instance_field()))) { 1571 return NULL; // memory is not Phi 1572 } 1573 1574 if (mem->is_Phi()) { 1575 if (!stable_phi(mem->as_Phi(), phase)) { 1576 return NULL; // Wait stable graph 1577 } 1578 uint cnt = mem->req(); 1579 // Check for loop invariant memory. 1580 if (cnt == 3) { 1581 for (uint i = 1; i < cnt; i++) { 1582 Node* in = mem->in(i); 1583 Node* m = optimize_memory_chain(in, t_oop, this, phase); 1584 if (m == mem) { 1585 if (i == 1) { 1586 // if the first edge was a loop, check second edge too. 1587 // If both are replaceable - we are in an infinite loop 1588 Node *n = optimize_memory_chain(mem->in(2), t_oop, this, phase); 1589 if (n == mem) { 1590 break; 1591 } 1592 } 1593 set_req(Memory, mem->in(cnt - i)); 1594 return this; // made change 1595 } 1596 } 1597 } 1598 } 1599 if (base_is_phi) { 1600 if (!stable_phi(base->as_Phi(), phase)) { 1601 return NULL; // Wait stable graph 1602 } 1603 uint cnt = base->req(); 1604 // Check for loop invariant memory. 1605 if (cnt == 3) { 1606 for (uint i = 1; i < cnt; i++) { 1607 if (base->in(i) == base) { 1608 return NULL; // Wait stable graph 1609 } 1610 } 1611 } 1612 } 1613 1614 // Split through Phi (see original code in loopopts.cpp). 1615 assert(C->have_alias_type(t_oop), "instance should have alias type"); 1616 1617 // Do nothing here if Identity will find a value 1618 // (to avoid infinite chain of value phis generation). 1619 if (this != Identity(phase)) { 1620 return NULL; 1621 } 1622 1623 // Select Region to split through. 1624 Node* region; 1625 if (!base_is_phi) { 1626 assert(mem->is_Phi(), "sanity"); 1627 region = mem->in(0); 1628 // Skip if the region dominates some control edge of the address. 1629 if (!MemNode::all_controls_dominate(address, region)) 1630 return NULL; 1631 } else if (!mem->is_Phi()) { 1632 assert(base_is_phi, "sanity"); 1633 region = base->in(0); 1634 // Skip if the region dominates some control edge of the memory. 1635 if (!MemNode::all_controls_dominate(mem, region)) 1636 return NULL; 1637 } else if (base->in(0) != mem->in(0)) { 1638 assert(base_is_phi && mem->is_Phi(), "sanity"); 1639 if (MemNode::all_controls_dominate(mem, base->in(0))) { 1640 region = base->in(0); 1641 } else if (MemNode::all_controls_dominate(address, mem->in(0))) { 1642 region = mem->in(0); 1643 } else { 1644 return NULL; // complex graph 1645 } 1646 } else { 1647 assert(base->in(0) == mem->in(0), "sanity"); 1648 region = mem->in(0); 1649 } 1650 1651 const Type* this_type = this->bottom_type(); 1652 int this_index = C->get_alias_index(t_oop); 1653 int this_offset = t_oop->offset(); 1654 int this_iid = t_oop->instance_id(); 1655 if (!t_oop->is_known_instance() && load_boxed_values) { 1656 // Use _idx of address base for boxed values. 1657 this_iid = base->_idx; 1658 } 1659 PhaseIterGVN* igvn = phase->is_IterGVN(); 1660 Node* phi = new PhiNode(region, this_type, NULL, mem->_idx, this_iid, this_index, this_offset); 1661 for (uint i = 1; i < region->req(); i++) { 1662 Node* x; 1663 Node* the_clone = NULL; 1664 Node* in = region->in(i); 1665 if (region->is_CountedLoop() && region->as_Loop()->is_strip_mined() && i == LoopNode::EntryControl && 1666 in != NULL && in->is_OuterStripMinedLoop()) { 1667 // No node should go in the outer strip mined loop 1668 in = in->in(LoopNode::EntryControl); 1669 } 1670 if (in == NULL || in == C->top()) { 1671 x = C->top(); // Dead path? Use a dead data op 1672 } else { 1673 x = this->clone(); // Else clone up the data op 1674 the_clone = x; // Remember for possible deletion. 1675 // Alter data node to use pre-phi inputs 1676 if (this->in(0) == region) { 1677 x->set_req(0, in); 1678 } else { 1679 x->set_req(0, NULL); 1680 } 1681 if (mem->is_Phi() && (mem->in(0) == region)) { 1682 x->set_req(Memory, mem->in(i)); // Use pre-Phi input for the clone. 1683 } 1684 if (address->is_Phi() && address->in(0) == region) { 1685 x->set_req(Address, address->in(i)); // Use pre-Phi input for the clone 1686 } 1687 if (base_is_phi && (base->in(0) == region)) { 1688 Node* base_x = base->in(i); // Clone address for loads from boxed objects. 1689 Node* adr_x = phase->transform(new AddPNode(base_x,base_x,address->in(AddPNode::Offset))); 1690 x->set_req(Address, adr_x); 1691 } 1692 } 1693 // Check for a 'win' on some paths 1694 const Type *t = x->Value(igvn); 1695 1696 bool singleton = t->singleton(); 1697 1698 // See comments in PhaseIdealLoop::split_thru_phi(). 1699 if (singleton && t == Type::TOP) { 1700 singleton &= region->is_Loop() && (i != LoopNode::EntryControl); 1701 } 1702 1703 if (singleton) { 1704 x = igvn->makecon(t); 1705 } else { 1706 // We now call Identity to try to simplify the cloned node. 1707 // Note that some Identity methods call phase->type(this). 1708 // Make sure that the type array is big enough for 1709 // our new node, even though we may throw the node away. 1710 // (This tweaking with igvn only works because x is a new node.) 1711 igvn->set_type(x, t); 1712 // If x is a TypeNode, capture any more-precise type permanently into Node 1713 // otherwise it will be not updated during igvn->transform since 1714 // igvn->type(x) is set to x->Value() already. 1715 x->raise_bottom_type(t); 1716 Node* y = x->Identity(igvn); 1717 if (y != x) { 1718 x = y; 1719 } else { 1720 y = igvn->hash_find_insert(x); 1721 if (y) { 1722 x = y; 1723 } else { 1724 // Else x is a new node we are keeping 1725 // We do not need register_new_node_with_optimizer 1726 // because set_type has already been called. 1727 igvn->_worklist.push(x); 1728 } 1729 } 1730 } 1731 if (x != the_clone && the_clone != NULL) { 1732 igvn->remove_dead_node(the_clone); 1733 } 1734 phi->set_req(i, x); 1735 } 1736 // Record Phi 1737 igvn->register_new_node_with_optimizer(phi); 1738 return phi; 1739 } 1740 1741 AllocateNode* LoadNode::is_new_object_mark_load(PhaseGVN *phase) const { 1742 if (Opcode() == Op_LoadX) { 1743 Node* address = in(MemNode::Address); 1744 AllocateNode* alloc = AllocateNode::Ideal_allocation(address, phase); 1745 Node* mem = in(MemNode::Memory); 1746 if (alloc != NULL && mem->is_Proj() && 1747 mem->in(0) != NULL && 1748 mem->in(0) == alloc->initialization() && 1749 alloc->initialization()->proj_out_or_null(0) != NULL) { 1750 return alloc; 1751 } 1752 } 1753 return NULL; 1754 } 1755 1756 1757 //------------------------------Ideal------------------------------------------ 1758 // If the load is from Field memory and the pointer is non-null, it might be possible to 1759 // zero out the control input. 1760 // If the offset is constant and the base is an object allocation, 1761 // try to hook me up to the exact initializing store. 1762 Node *LoadNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1763 if (has_pinned_control_dependency()) { 1764 return NULL; 1765 } 1766 Node* p = MemNode::Ideal_common(phase, can_reshape); 1767 if (p) return (p == NodeSentinel) ? NULL : p; 1768 1769 Node* ctrl = in(MemNode::Control); 1770 Node* address = in(MemNode::Address); 1771 bool progress = false; 1772 1773 bool addr_mark = ((phase->type(address)->isa_oopptr() || phase->type(address)->isa_narrowoop()) && 1774 phase->type(address)->is_ptr()->offset() == oopDesc::mark_offset_in_bytes()); 1775 1776 // Skip up past a SafePoint control. Cannot do this for Stores because 1777 // pointer stores & cardmarks must stay on the same side of a SafePoint. 1778 if( ctrl != NULL && ctrl->Opcode() == Op_SafePoint && 1779 phase->C->get_alias_index(phase->type(address)->is_ptr()) != Compile::AliasIdxRaw && 1780 !addr_mark && 1781 (depends_only_on_test() || has_unknown_control_dependency())) { 1782 ctrl = ctrl->in(0); 1783 set_req(MemNode::Control,ctrl); 1784 progress = true; 1785 } 1786 1787 intptr_t ignore = 0; 1788 Node* base = AddPNode::Ideal_base_and_offset(address, phase, ignore); 1789 if (base != NULL 1790 && phase->C->get_alias_index(phase->type(address)->is_ptr()) != Compile::AliasIdxRaw) { 1791 // Check for useless control edge in some common special cases 1792 if (in(MemNode::Control) != NULL 1793 && can_remove_control() 1794 && phase->type(base)->higher_equal(TypePtr::NOTNULL) 1795 && all_controls_dominate(base, phase->C->start())) { 1796 // A method-invariant, non-null address (constant or 'this' argument). 1797 set_req(MemNode::Control, NULL); 1798 progress = true; 1799 } 1800 } 1801 1802 Node* mem = in(MemNode::Memory); 1803 const TypePtr *addr_t = phase->type(address)->isa_ptr(); 1804 1805 if (can_reshape && (addr_t != NULL)) { 1806 // try to optimize our memory input 1807 Node* opt_mem = MemNode::optimize_memory_chain(mem, addr_t, this, phase); 1808 if (opt_mem != mem) { 1809 set_req_X(MemNode::Memory, opt_mem, phase); 1810 if (phase->type( opt_mem ) == Type::TOP) return NULL; 1811 return this; 1812 } 1813 const TypeOopPtr *t_oop = addr_t->isa_oopptr(); 1814 if ((t_oop != NULL) && 1815 (t_oop->is_known_instance_field() || 1816 t_oop->is_ptr_to_boxed_value())) { 1817 PhaseIterGVN *igvn = phase->is_IterGVN(); 1818 assert(igvn != NULL, "must be PhaseIterGVN when can_reshape is true"); 1819 if (igvn->_worklist.member(opt_mem)) { 1820 // Delay this transformation until memory Phi is processed. 1821 igvn->_worklist.push(this); 1822 return NULL; 1823 } 1824 // Split instance field load through Phi. 1825 Node* result = split_through_phi(phase); 1826 if (result != NULL) return result; 1827 1828 if (t_oop->is_ptr_to_boxed_value()) { 1829 Node* result = eliminate_autobox(igvn); 1830 if (result != NULL) return result; 1831 } 1832 } 1833 } 1834 1835 // Is there a dominating load that loads the same value? Leave 1836 // anything that is not a load of a field/array element (like 1837 // barriers etc.) alone 1838 if (in(0) != NULL && !adr_type()->isa_rawptr() && can_reshape) { 1839 for (DUIterator_Fast imax, i = mem->fast_outs(imax); i < imax; i++) { 1840 Node *use = mem->fast_out(i); 1841 if (use != this && 1842 use->Opcode() == Opcode() && 1843 use->in(0) != NULL && 1844 use->in(0) != in(0) && 1845 use->in(Address) == in(Address)) { 1846 Node* ctl = in(0); 1847 for (int i = 0; i < 10 && ctl != NULL; i++) { 1848 ctl = IfNode::up_one_dom(ctl); 1849 if (ctl == use->in(0)) { 1850 set_req(0, use->in(0)); 1851 return this; 1852 } 1853 } 1854 } 1855 } 1856 } 1857 1858 // Check for prior store with a different base or offset; make Load 1859 // independent. Skip through any number of them. Bail out if the stores 1860 // are in an endless dead cycle and report no progress. This is a key 1861 // transform for Reflection. However, if after skipping through the Stores 1862 // we can't then fold up against a prior store do NOT do the transform as 1863 // this amounts to using the 'Oracle' model of aliasing. It leaves the same 1864 // array memory alive twice: once for the hoisted Load and again after the 1865 // bypassed Store. This situation only works if EVERYBODY who does 1866 // anti-dependence work knows how to bypass. I.e. we need all 1867 // anti-dependence checks to ask the same Oracle. Right now, that Oracle is 1868 // the alias index stuff. So instead, peek through Stores and IFF we can 1869 // fold up, do so. 1870 Node* prev_mem = find_previous_store(phase); 1871 if (prev_mem != NULL) { 1872 Node* value = can_see_arraycopy_value(prev_mem, phase); 1873 if (value != NULL) { 1874 return value; 1875 } 1876 } 1877 // Steps (a), (b): Walk past independent stores to find an exact match. 1878 if (prev_mem != NULL && prev_mem != in(MemNode::Memory)) { 1879 // (c) See if we can fold up on the spot, but don't fold up here. 1880 // Fold-up might require truncation (for LoadB/LoadS/LoadUS) or 1881 // just return a prior value, which is done by Identity calls. 1882 if (can_see_stored_value(prev_mem, phase)) { 1883 // Make ready for step (d): 1884 set_req_X(MemNode::Memory, prev_mem, phase); 1885 return this; 1886 } 1887 } 1888 1889 return progress ? this : NULL; 1890 } 1891 1892 // Helper to recognize certain Klass fields which are invariant across 1893 // some group of array types (e.g., int[] or all T[] where T < Object). 1894 const Type* 1895 LoadNode::load_array_final_field(const TypeKlassPtr *tkls, 1896 ciKlass* klass) const { 1897 if (tkls->offset() == in_bytes(Klass::modifier_flags_offset())) { 1898 // The field is Klass::_modifier_flags. Return its (constant) value. 1899 // (Folds up the 2nd indirection in aClassConstant.getModifiers().) 1900 assert(this->Opcode() == Op_LoadI, "must load an int from _modifier_flags"); 1901 return TypeInt::make(klass->modifier_flags()); 1902 } 1903 if (tkls->offset() == in_bytes(Klass::access_flags_offset())) { 1904 // The field is Klass::_access_flags. Return its (constant) value. 1905 // (Folds up the 2nd indirection in Reflection.getClassAccessFlags(aClassConstant).) 1906 assert(this->Opcode() == Op_LoadI, "must load an int from _access_flags"); 1907 return TypeInt::make(klass->access_flags()); 1908 } 1909 if (tkls->offset() == in_bytes(Klass::layout_helper_offset())) { 1910 // The field is Klass::_layout_helper. Return its constant value if known. 1911 assert(this->Opcode() == Op_LoadI, "must load an int from _layout_helper"); 1912 return TypeInt::make(klass->layout_helper()); 1913 } 1914 1915 // No match. 1916 return NULL; 1917 } 1918 1919 //------------------------------Value----------------------------------------- 1920 const Type* LoadNode::Value(PhaseGVN* phase) const { 1921 // Either input is TOP ==> the result is TOP 1922 Node* mem = in(MemNode::Memory); 1923 const Type *t1 = phase->type(mem); 1924 if (t1 == Type::TOP) return Type::TOP; 1925 Node* adr = in(MemNode::Address); 1926 const TypePtr* tp = phase->type(adr)->isa_ptr(); 1927 if (tp == NULL || tp->empty()) return Type::TOP; 1928 int off = tp->offset(); 1929 assert(off != Type::OffsetTop, "case covered by TypePtr::empty"); 1930 Compile* C = phase->C; 1931 1932 // Try to guess loaded type from pointer type 1933 if (tp->isa_aryptr()) { 1934 const TypeAryPtr* ary = tp->is_aryptr(); 1935 const Type* t = ary->elem(); 1936 1937 // Determine whether the reference is beyond the header or not, by comparing 1938 // the offset against the offset of the start of the array's data. 1939 // Different array types begin at slightly different offsets (12 vs. 16). 1940 // We choose T_BYTE as an example base type that is least restrictive 1941 // as to alignment, which will therefore produce the smallest 1942 // possible base offset. 1943 const int min_base_off = arrayOopDesc::base_offset_in_bytes(T_BYTE); 1944 const bool off_beyond_header = (off >= min_base_off); 1945 1946 // Try to constant-fold a stable array element. 1947 if (FoldStableValues && !is_mismatched_access() && ary->is_stable()) { 1948 // Make sure the reference is not into the header and the offset is constant 1949 ciObject* aobj = ary->const_oop(); 1950 if (aobj != NULL && off_beyond_header && adr->is_AddP() && off != Type::OffsetBot) { 1951 int stable_dimension = (ary->stable_dimension() > 0 ? ary->stable_dimension() - 1 : 0); 1952 const Type* con_type = Type::make_constant_from_array_element(aobj->as_array(), off, 1953 stable_dimension, 1954 memory_type(), is_unsigned()); 1955 if (con_type != NULL) { 1956 return con_type; 1957 } 1958 } 1959 } 1960 1961 // Don't do this for integer types. There is only potential profit if 1962 // the element type t is lower than _type; that is, for int types, if _type is 1963 // more restrictive than t. This only happens here if one is short and the other 1964 // char (both 16 bits), and in those cases we've made an intentional decision 1965 // to use one kind of load over the other. See AndINode::Ideal and 4965907. 1966 // Also, do not try to narrow the type for a LoadKlass, regardless of offset. 1967 // 1968 // Yes, it is possible to encounter an expression like (LoadKlass p1:(AddP x x 8)) 1969 // where the _gvn.type of the AddP is wider than 8. This occurs when an earlier 1970 // copy p0 of (AddP x x 8) has been proven equal to p1, and the p0 has been 1971 // subsumed by p1. If p1 is on the worklist but has not yet been re-transformed, 1972 // it is possible that p1 will have a type like Foo*[int+]:NotNull*+any. 1973 // In fact, that could have been the original type of p1, and p1 could have 1974 // had an original form like p1:(AddP x x (LShiftL quux 3)), where the 1975 // expression (LShiftL quux 3) independently optimized to the constant 8. 1976 if ((t->isa_int() == NULL) && (t->isa_long() == NULL) 1977 && (_type->isa_vect() == NULL) 1978 && !ary->is_flat() 1979 && Opcode() != Op_LoadKlass && Opcode() != Op_LoadNKlass) { 1980 // t might actually be lower than _type, if _type is a unique 1981 // concrete subclass of abstract class t. 1982 if (off_beyond_header || off == Type::OffsetBot) { // is the offset beyond the header? 1983 const Type* jt = t->join_speculative(_type); 1984 // In any case, do not allow the join, per se, to empty out the type. 1985 if (jt->empty() && !t->empty()) { 1986 // This can happen if a interface-typed array narrows to a class type. 1987 jt = _type; 1988 } 1989 #ifdef ASSERT 1990 if (phase->C->eliminate_boxing() && adr->is_AddP()) { 1991 // The pointers in the autobox arrays are always non-null 1992 Node* base = adr->in(AddPNode::Base); 1993 if ((base != NULL) && base->is_DecodeN()) { 1994 // Get LoadN node which loads IntegerCache.cache field 1995 base = base->in(1); 1996 } 1997 if ((base != NULL) && base->is_Con()) { 1998 const TypeAryPtr* base_type = base->bottom_type()->isa_aryptr(); 1999 if ((base_type != NULL) && base_type->is_autobox_cache()) { 2000 // It could be narrow oop 2001 assert(jt->make_ptr()->ptr() == TypePtr::NotNull,"sanity"); 2002 } 2003 } 2004 } 2005 #endif 2006 return jt; 2007 } 2008 } 2009 } else if (tp->base() == Type::InstPtr) { 2010 assert( off != Type::OffsetBot || 2011 // arrays can be cast to Objects 2012 !tp->isa_instptr() || 2013 tp->is_instptr()->instance_klass()->is_java_lang_Object() || 2014 // Default value load 2015 tp->is_instptr()->instance_klass() == ciEnv::current()->Class_klass() || 2016 // unsafe field access may not have a constant offset 2017 C->has_unsafe_access(), 2018 "Field accesses must be precise" ); 2019 // For oop loads, we expect the _type to be precise. 2020 2021 const TypeInstPtr* tinst = tp->is_instptr(); 2022 BasicType bt = memory_type(); 2023 2024 // Optimize loads from constant fields. 2025 ciObject* const_oop = tinst->const_oop(); 2026 if (!is_mismatched_access() && off != Type::OffsetBot && const_oop != NULL && const_oop->is_instance()) { 2027 ciType* mirror_type = const_oop->as_instance()->java_mirror_type(); 2028 if (mirror_type != NULL) { 2029 const Type* const_oop = NULL; 2030 ciInlineKlass* vk = mirror_type->is_inlinetype() ? mirror_type->as_inline_klass() : NULL; 2031 // Fold default value loads 2032 if (vk != NULL && off == vk->default_value_offset()) { 2033 const_oop = TypeInstPtr::make(vk->default_instance()); 2034 } 2035 // Fold class mirror loads 2036 if (off == java_lang_Class::primary_mirror_offset()) { 2037 const_oop = (vk == NULL) ? TypePtr::NULL_PTR : TypeInstPtr::make(vk->ref_instance()); 2038 } else if (off == java_lang_Class::secondary_mirror_offset()) { 2039 const_oop = (vk == NULL) ? TypePtr::NULL_PTR : TypeInstPtr::make(vk->val_instance()); 2040 } 2041 if (const_oop != NULL) { 2042 return (bt == T_NARROWOOP) ? const_oop->make_narrowoop() : const_oop; 2043 } 2044 } 2045 const Type* con_type = Type::make_constant_from_field(const_oop->as_instance(), off, is_unsigned(), bt); 2046 if (con_type != NULL) { 2047 return con_type; 2048 } 2049 } 2050 } else if (tp->base() == Type::KlassPtr || tp->base() == Type::InstKlassPtr || tp->base() == Type::AryKlassPtr) { 2051 assert(off != Type::OffsetBot || 2052 !tp->isa_instklassptr() || 2053 // arrays can be cast to Objects 2054 tp->isa_instklassptr()->instance_klass()->is_java_lang_Object() || 2055 // also allow array-loading from the primary supertype 2056 // array during subtype checks 2057 Opcode() == Op_LoadKlass, 2058 "Field accesses must be precise"); 2059 // For klass/static loads, we expect the _type to be precise 2060 } else if (tp->base() == Type::RawPtr && !StressReflectiveCode) { 2061 if (adr->is_Load() && off == 0) { 2062 /* With mirrors being an indirect in the Klass* 2063 * the VM is now using two loads. LoadKlass(LoadP(LoadP(Klass, mirror_offset), zero_offset)) 2064 * The LoadP from the Klass has a RawPtr type (see LibraryCallKit::load_mirror_from_klass). 2065 * 2066 * So check the type and klass of the node before the LoadP. 2067 */ 2068 Node* adr2 = adr->in(MemNode::Address); 2069 const TypeKlassPtr* tkls = phase->type(adr2)->isa_klassptr(); 2070 if (tkls != NULL) { 2071 if (tkls->is_loaded() && tkls->klass_is_exact() && tkls->offset() == in_bytes(Klass::java_mirror_offset())) { 2072 ciKlass* klass = tkls->exact_klass(); 2073 assert(adr->Opcode() == Op_LoadP, "must load an oop from _java_mirror"); 2074 assert(Opcode() == Op_LoadP, "must load an oop from _java_mirror"); 2075 return TypeInstPtr::make(klass->java_mirror()); 2076 } 2077 } 2078 } else { 2079 // Check for a load of the default value offset from the InlineKlassFixedBlock: 2080 // LoadI(LoadP(inline_klass, adr_inlineklass_fixed_block_offset), default_value_offset_offset) 2081 intptr_t offset = 0; 2082 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset); 2083 if (base != NULL && base->is_Load() && offset == in_bytes(InlineKlass::default_value_offset_offset())) { 2084 const TypeKlassPtr* tkls = phase->type(base->in(MemNode::Address))->isa_klassptr(); 2085 if (tkls != NULL && tkls->is_loaded() && tkls->klass_is_exact() && tkls->exact_klass()->is_inlinetype() && 2086 tkls->offset() == in_bytes(InstanceKlass::adr_inlineklass_fixed_block_offset())) { 2087 assert(base->Opcode() == Op_LoadP, "must load an oop from klass"); 2088 assert(Opcode() == Op_LoadI, "must load an int from fixed block"); 2089 return TypeInt::make(tkls->exact_klass()->as_inline_klass()->default_value_offset()); 2090 } 2091 } 2092 } 2093 } 2094 2095 const TypeKlassPtr *tkls = tp->isa_klassptr(); 2096 if (tkls != NULL) { 2097 if (tkls->is_loaded() && tkls->klass_is_exact()) { 2098 ciKlass* klass = tkls->exact_klass(); 2099 // We are loading a field from a Klass metaobject whose identity 2100 // is known at compile time (the type is "exact" or "precise"). 2101 // Check for fields we know are maintained as constants by the VM. 2102 if (tkls->offset() == in_bytes(Klass::super_check_offset_offset())) { 2103 // The field is Klass::_super_check_offset. Return its (constant) value. 2104 // (Folds up type checking code.) 2105 assert(Opcode() == Op_LoadI, "must load an int from _super_check_offset"); 2106 return TypeInt::make(klass->super_check_offset()); 2107 } 2108 // Compute index into primary_supers array 2109 juint depth = (tkls->offset() - in_bytes(Klass::primary_supers_offset())) / sizeof(Klass*); 2110 // Check for overflowing; use unsigned compare to handle the negative case. 2111 if( depth < ciKlass::primary_super_limit() ) { 2112 // The field is an element of Klass::_primary_supers. Return its (constant) value. 2113 // (Folds up type checking code.) 2114 assert(Opcode() == Op_LoadKlass, "must load a klass from _primary_supers"); 2115 ciKlass *ss = klass->super_of_depth(depth); 2116 return ss ? TypeKlassPtr::make(ss, Type::trust_interfaces) : TypePtr::NULL_PTR; 2117 } 2118 const Type* aift = load_array_final_field(tkls, klass); 2119 if (aift != NULL) return aift; 2120 } 2121 2122 // We can still check if we are loading from the primary_supers array at a 2123 // shallow enough depth. Even though the klass is not exact, entries less 2124 // than or equal to its super depth are correct. 2125 if (tkls->is_loaded()) { 2126 ciKlass* klass = NULL; 2127 if (tkls->isa_instklassptr()) { 2128 klass = tkls->is_instklassptr()->instance_klass(); 2129 } else { 2130 int dims; 2131 const Type* inner = tkls->is_aryklassptr()->base_element_type(dims); 2132 if (inner->isa_instklassptr()) { 2133 klass = inner->is_instklassptr()->instance_klass(); 2134 klass = ciObjArrayKlass::make(klass, dims); 2135 } 2136 } 2137 if (klass != NULL) { 2138 // Compute index into primary_supers array 2139 juint depth = (tkls->offset() - in_bytes(Klass::primary_supers_offset())) / sizeof(Klass*); 2140 // Check for overflowing; use unsigned compare to handle the negative case. 2141 if (depth < ciKlass::primary_super_limit() && 2142 depth <= klass->super_depth()) { // allow self-depth checks to handle self-check case 2143 // The field is an element of Klass::_primary_supers. Return its (constant) value. 2144 // (Folds up type checking code.) 2145 assert(Opcode() == Op_LoadKlass, "must load a klass from _primary_supers"); 2146 ciKlass *ss = klass->super_of_depth(depth); 2147 return ss ? TypeKlassPtr::make(ss, Type::trust_interfaces) : TypePtr::NULL_PTR; 2148 } 2149 } 2150 } 2151 2152 // If the type is enough to determine that the thing is not an array, 2153 // we can give the layout_helper a positive interval type. 2154 // This will help short-circuit some reflective code. 2155 if (tkls->offset() == in_bytes(Klass::layout_helper_offset()) && 2156 tkls->isa_instklassptr() && // not directly typed as an array 2157 !tkls->is_instklassptr()->instance_klass()->is_java_lang_Object() // not the supertype of all T[] and specifically not Serializable & Cloneable 2158 ) { 2159 // Note: When interfaces are reliable, we can narrow the interface 2160 // test to (klass != Serializable && klass != Cloneable). 2161 assert(Opcode() == Op_LoadI, "must load an int from _layout_helper"); 2162 jint min_size = Klass::instance_layout_helper(oopDesc::header_size(), false); 2163 // The key property of this type is that it folds up tests 2164 // for array-ness, since it proves that the layout_helper is positive. 2165 // Thus, a generic value like the basic object layout helper works fine. 2166 return TypeInt::make(min_size, max_jint, Type::WidenMin); 2167 } 2168 } 2169 2170 // If we are loading from a freshly-allocated object, produce a zero, 2171 // if the load is provably beyond the header of the object. 2172 // (Also allow a variable load from a fresh array to produce zero.) 2173 const TypeOopPtr *tinst = tp->isa_oopptr(); 2174 bool is_instance = (tinst != NULL) && tinst->is_known_instance_field(); 2175 bool is_boxed_value = (tinst != NULL) && tinst->is_ptr_to_boxed_value(); 2176 if (ReduceFieldZeroing || is_instance || is_boxed_value) { 2177 Node* value = can_see_stored_value(mem,phase); 2178 if (value != NULL && value->is_Con()) { 2179 assert(value->bottom_type()->higher_equal(_type),"sanity"); 2180 return value->bottom_type(); 2181 } 2182 } 2183 2184 bool is_vect = (_type->isa_vect() != NULL); 2185 if (is_instance && !is_vect) { 2186 // If we have an instance type and our memory input is the 2187 // programs's initial memory state, there is no matching store, 2188 // so just return a zero of the appropriate type - 2189 // except if it is vectorized - then we have no zero constant. 2190 Node *mem = in(MemNode::Memory); 2191 if (mem->is_Parm() && mem->in(0)->is_Start()) { 2192 assert(mem->as_Parm()->_con == TypeFunc::Memory, "must be memory Parm"); 2193 return Type::get_zero_type(_type->basic_type()); 2194 } 2195 } 2196 Node* alloc = is_new_object_mark_load(phase); 2197 if (alloc != NULL) { 2198 if (EnableValhalla) { 2199 // The mark word may contain property bits (inline, flat, null-free) 2200 Node* klass_node = alloc->in(AllocateNode::KlassNode); 2201 const TypeKlassPtr* tkls = phase->type(klass_node)->is_klassptr(); 2202 if (tkls->is_loaded() && tkls->klass_is_exact()) { 2203 return TypeX::make(tkls->exact_klass()->prototype_header().value()); 2204 } 2205 } else { 2206 return TypeX::make(markWord::prototype().value()); 2207 } 2208 } 2209 2210 return _type; 2211 } 2212 2213 //------------------------------match_edge------------------------------------- 2214 // Do we Match on this edge index or not? Match only the address. 2215 uint LoadNode::match_edge(uint idx) const { 2216 return idx == MemNode::Address; 2217 } 2218 2219 //--------------------------LoadBNode::Ideal-------------------------------------- 2220 // 2221 // If the previous store is to the same address as this load, 2222 // and the value stored was larger than a byte, replace this load 2223 // with the value stored truncated to a byte. If no truncation is 2224 // needed, the replacement is done in LoadNode::Identity(). 2225 // 2226 Node* LoadBNode::Ideal(PhaseGVN* phase, bool can_reshape) { 2227 Node* mem = in(MemNode::Memory); 2228 Node* value = can_see_stored_value(mem,phase); 2229 if (value != NULL) { 2230 Node* narrow = Compile::narrow_value(T_BYTE, value, _type, phase, false); 2231 if (narrow != value) { 2232 return narrow; 2233 } 2234 } 2235 // Identity call will handle the case where truncation is not needed. 2236 return LoadNode::Ideal(phase, can_reshape); 2237 } 2238 2239 const Type* LoadBNode::Value(PhaseGVN* phase) const { 2240 Node* mem = in(MemNode::Memory); 2241 Node* value = can_see_stored_value(mem,phase); 2242 if (value != NULL && value->is_Con() && 2243 !value->bottom_type()->higher_equal(_type)) { 2244 // If the input to the store does not fit with the load's result type, 2245 // it must be truncated. We can't delay until Ideal call since 2246 // a singleton Value is needed for split_thru_phi optimization. 2247 int con = value->get_int(); 2248 return TypeInt::make((con << 24) >> 24); 2249 } 2250 return LoadNode::Value(phase); 2251 } 2252 2253 //--------------------------LoadUBNode::Ideal------------------------------------- 2254 // 2255 // If the previous store is to the same address as this load, 2256 // and the value stored was larger than a byte, replace this load 2257 // with the value stored truncated to a byte. If no truncation is 2258 // needed, the replacement is done in LoadNode::Identity(). 2259 // 2260 Node* LoadUBNode::Ideal(PhaseGVN* phase, bool can_reshape) { 2261 Node* mem = in(MemNode::Memory); 2262 Node* value = can_see_stored_value(mem, phase); 2263 if (value != NULL) { 2264 Node* narrow = Compile::narrow_value(T_BOOLEAN, value, _type, phase, false); 2265 if (narrow != value) { 2266 return narrow; 2267 } 2268 } 2269 // Identity call will handle the case where truncation is not needed. 2270 return LoadNode::Ideal(phase, can_reshape); 2271 } 2272 2273 const Type* LoadUBNode::Value(PhaseGVN* phase) const { 2274 Node* mem = in(MemNode::Memory); 2275 Node* value = can_see_stored_value(mem,phase); 2276 if (value != NULL && value->is_Con() && 2277 !value->bottom_type()->higher_equal(_type)) { 2278 // If the input to the store does not fit with the load's result type, 2279 // it must be truncated. We can't delay until Ideal call since 2280 // a singleton Value is needed for split_thru_phi optimization. 2281 int con = value->get_int(); 2282 return TypeInt::make(con & 0xFF); 2283 } 2284 return LoadNode::Value(phase); 2285 } 2286 2287 //--------------------------LoadUSNode::Ideal------------------------------------- 2288 // 2289 // If the previous store is to the same address as this load, 2290 // and the value stored was larger than a char, replace this load 2291 // with the value stored truncated to a char. If no truncation is 2292 // needed, the replacement is done in LoadNode::Identity(). 2293 // 2294 Node* LoadUSNode::Ideal(PhaseGVN* phase, bool can_reshape) { 2295 Node* mem = in(MemNode::Memory); 2296 Node* value = can_see_stored_value(mem,phase); 2297 if (value != NULL) { 2298 Node* narrow = Compile::narrow_value(T_CHAR, value, _type, phase, false); 2299 if (narrow != value) { 2300 return narrow; 2301 } 2302 } 2303 // Identity call will handle the case where truncation is not needed. 2304 return LoadNode::Ideal(phase, can_reshape); 2305 } 2306 2307 const Type* LoadUSNode::Value(PhaseGVN* phase) const { 2308 Node* mem = in(MemNode::Memory); 2309 Node* value = can_see_stored_value(mem,phase); 2310 if (value != NULL && value->is_Con() && 2311 !value->bottom_type()->higher_equal(_type)) { 2312 // If the input to the store does not fit with the load's result type, 2313 // it must be truncated. We can't delay until Ideal call since 2314 // a singleton Value is needed for split_thru_phi optimization. 2315 int con = value->get_int(); 2316 return TypeInt::make(con & 0xFFFF); 2317 } 2318 return LoadNode::Value(phase); 2319 } 2320 2321 //--------------------------LoadSNode::Ideal-------------------------------------- 2322 // 2323 // If the previous store is to the same address as this load, 2324 // and the value stored was larger than a short, replace this load 2325 // with the value stored truncated to a short. If no truncation is 2326 // needed, the replacement is done in LoadNode::Identity(). 2327 // 2328 Node* LoadSNode::Ideal(PhaseGVN* phase, bool can_reshape) { 2329 Node* mem = in(MemNode::Memory); 2330 Node* value = can_see_stored_value(mem,phase); 2331 if (value != NULL) { 2332 Node* narrow = Compile::narrow_value(T_SHORT, value, _type, phase, false); 2333 if (narrow != value) { 2334 return narrow; 2335 } 2336 } 2337 // Identity call will handle the case where truncation is not needed. 2338 return LoadNode::Ideal(phase, can_reshape); 2339 } 2340 2341 const Type* LoadSNode::Value(PhaseGVN* phase) const { 2342 Node* mem = in(MemNode::Memory); 2343 Node* value = can_see_stored_value(mem,phase); 2344 if (value != NULL && value->is_Con() && 2345 !value->bottom_type()->higher_equal(_type)) { 2346 // If the input to the store does not fit with the load's result type, 2347 // it must be truncated. We can't delay until Ideal call since 2348 // a singleton Value is needed for split_thru_phi optimization. 2349 int con = value->get_int(); 2350 return TypeInt::make((con << 16) >> 16); 2351 } 2352 return LoadNode::Value(phase); 2353 } 2354 2355 //============================================================================= 2356 //----------------------------LoadKlassNode::make------------------------------ 2357 // Polymorphic factory method: 2358 Node* LoadKlassNode::make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* at, 2359 const TypeKlassPtr* tk) { 2360 // sanity check the alias category against the created node type 2361 const TypePtr *adr_type = adr->bottom_type()->isa_ptr(); 2362 assert(adr_type != NULL, "expecting TypeKlassPtr"); 2363 #ifdef _LP64 2364 if (adr_type->is_ptr_to_narrowklass()) { 2365 assert(UseCompressedClassPointers, "no compressed klasses"); 2366 Node* load_klass = gvn.transform(new LoadNKlassNode(ctl, mem, adr, at, tk->make_narrowklass(), MemNode::unordered)); 2367 return new DecodeNKlassNode(load_klass, load_klass->bottom_type()->make_ptr()); 2368 } 2369 #endif 2370 assert(!adr_type->is_ptr_to_narrowklass() && !adr_type->is_ptr_to_narrowoop(), "should have got back a narrow oop"); 2371 return new LoadKlassNode(ctl, mem, adr, at, tk, MemNode::unordered); 2372 } 2373 2374 //------------------------------Value------------------------------------------ 2375 const Type* LoadKlassNode::Value(PhaseGVN* phase) const { 2376 return klass_value_common(phase); 2377 } 2378 2379 // In most cases, LoadKlassNode does not have the control input set. If the control 2380 // input is set, it must not be removed (by LoadNode::Ideal()). 2381 bool LoadKlassNode::can_remove_control() const { 2382 return false; 2383 } 2384 2385 const Type* LoadNode::klass_value_common(PhaseGVN* phase) const { 2386 // Either input is TOP ==> the result is TOP 2387 const Type *t1 = phase->type( in(MemNode::Memory) ); 2388 if (t1 == Type::TOP) return Type::TOP; 2389 Node *adr = in(MemNode::Address); 2390 const Type *t2 = phase->type( adr ); 2391 if (t2 == Type::TOP) return Type::TOP; 2392 const TypePtr *tp = t2->is_ptr(); 2393 if (TypePtr::above_centerline(tp->ptr()) || 2394 tp->ptr() == TypePtr::Null) return Type::TOP; 2395 2396 // Return a more precise klass, if possible 2397 const TypeInstPtr *tinst = tp->isa_instptr(); 2398 if (tinst != NULL) { 2399 ciInstanceKlass* ik = tinst->instance_klass(); 2400 int offset = tinst->offset(); 2401 if (ik == phase->C->env()->Class_klass() 2402 && (offset == java_lang_Class::klass_offset() || 2403 offset == java_lang_Class::array_klass_offset())) { 2404 // We are loading a special hidden field from a Class mirror object, 2405 // the field which points to the VM's Klass metaobject. 2406 bool null_free = false; 2407 ciType* t = tinst->java_mirror_type(&null_free); 2408 // java_mirror_type returns non-null for compile-time Class constants. 2409 if (t != NULL) { 2410 // constant oop => constant klass 2411 if (offset == java_lang_Class::array_klass_offset()) { 2412 if (t->is_void()) { 2413 // We cannot create a void array. Since void is a primitive type return null 2414 // klass. Users of this result need to do a null check on the returned klass. 2415 return TypePtr::NULL_PTR; 2416 } 2417 return TypeKlassPtr::make(ciArrayKlass::make(t, null_free), Type::trust_interfaces); 2418 } 2419 if (!t->is_klass()) { 2420 // a primitive Class (e.g., int.class) has NULL for a klass field 2421 return TypePtr::NULL_PTR; 2422 } 2423 // (Folds up the 1st indirection in aClassConstant.getModifiers().) 2424 return TypeKlassPtr::make(t->as_klass(), Type::trust_interfaces); 2425 } 2426 // non-constant mirror, so we can't tell what's going on 2427 } 2428 if (!tinst->is_loaded()) 2429 return _type; // Bail out if not loaded 2430 if (offset == oopDesc::klass_offset_in_bytes()) { 2431 return tinst->as_klass_type(true); 2432 } 2433 } 2434 2435 // Check for loading klass from an array 2436 const TypeAryPtr* tary = tp->isa_aryptr(); 2437 if (tary != NULL && tary->elem() != Type::BOTTOM && 2438 tary->offset() == oopDesc::klass_offset_in_bytes()) { 2439 return tary->as_klass_type(true); 2440 } 2441 2442 // Check for loading klass from an array klass 2443 const TypeKlassPtr *tkls = tp->isa_klassptr(); 2444 if (tkls != NULL && !StressReflectiveCode) { 2445 if (!tkls->is_loaded()) 2446 return _type; // Bail out if not loaded 2447 if (tkls->isa_aryklassptr() && tkls->is_aryklassptr()->elem()->isa_klassptr() && 2448 tkls->offset() == in_bytes(ObjArrayKlass::element_klass_offset())) { 2449 // // Always returning precise element type is incorrect, 2450 // // e.g., element type could be object and array may contain strings 2451 // return TypeKlassPtr::make(TypePtr::Constant, elem, 0); 2452 2453 // The array's TypeKlassPtr was declared 'precise' or 'not precise' 2454 // according to the element type's subclassing. 2455 return tkls->is_aryklassptr()->elem(); 2456 } 2457 if (tkls->isa_instklassptr() != NULL && tkls->klass_is_exact() && 2458 tkls->offset() == in_bytes(Klass::super_offset())) { 2459 ciKlass* sup = tkls->is_instklassptr()->instance_klass()->super(); 2460 // The field is Klass::_super. Return its (constant) value. 2461 // (Folds up the 2nd indirection in aClassConstant.getSuperClass().) 2462 return sup ? TypeKlassPtr::make(sup, Type::trust_interfaces) : TypePtr::NULL_PTR; 2463 } 2464 } 2465 2466 // Bailout case 2467 return LoadNode::Value(phase); 2468 } 2469 2470 //------------------------------Identity--------------------------------------- 2471 // To clean up reflective code, simplify k.java_mirror.as_klass to plain k. 2472 // Also feed through the klass in Allocate(...klass...)._klass. 2473 Node* LoadKlassNode::Identity(PhaseGVN* phase) { 2474 return klass_identity_common(phase); 2475 } 2476 2477 Node* LoadNode::klass_identity_common(PhaseGVN* phase) { 2478 Node* x = LoadNode::Identity(phase); 2479 if (x != this) return x; 2480 2481 // Take apart the address into an oop and offset. 2482 // Return 'this' if we cannot. 2483 Node* adr = in(MemNode::Address); 2484 intptr_t offset = 0; 2485 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset); 2486 if (base == NULL) return this; 2487 const TypeOopPtr* toop = phase->type(adr)->isa_oopptr(); 2488 if (toop == NULL) return this; 2489 2490 // Step over potential GC barrier for OopHandle resolve 2491 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2(); 2492 if (bs->is_gc_barrier_node(base)) { 2493 base = bs->step_over_gc_barrier(base); 2494 } 2495 2496 // We can fetch the klass directly through an AllocateNode. 2497 // This works even if the klass is not constant (clone or newArray). 2498 if (offset == oopDesc::klass_offset_in_bytes()) { 2499 Node* allocated_klass = AllocateNode::Ideal_klass(base, phase); 2500 if (allocated_klass != NULL) { 2501 return allocated_klass; 2502 } 2503 } 2504 2505 // Simplify k.java_mirror.as_klass to plain k, where k is a Klass*. 2506 // See inline_native_Class_query for occurrences of these patterns. 2507 // Java Example: x.getClass().isAssignableFrom(y) 2508 // 2509 // This improves reflective code, often making the Class 2510 // mirror go completely dead. (Current exception: Class 2511 // mirrors may appear in debug info, but we could clean them out by 2512 // introducing a new debug info operator for Klass.java_mirror). 2513 2514 if (toop->isa_instptr() && toop->is_instptr()->instance_klass() == phase->C->env()->Class_klass() 2515 && offset == java_lang_Class::klass_offset()) { 2516 if (base->is_Load()) { 2517 Node* base2 = base->in(MemNode::Address); 2518 if (base2->is_Load()) { /* direct load of a load which is the OopHandle */ 2519 Node* adr2 = base2->in(MemNode::Address); 2520 const TypeKlassPtr* tkls = phase->type(adr2)->isa_klassptr(); 2521 if (tkls != NULL && !tkls->empty() 2522 && (tkls->isa_instklassptr() || tkls->isa_aryklassptr()) 2523 && adr2->is_AddP() 2524 ) { 2525 int mirror_field = in_bytes(Klass::java_mirror_offset()); 2526 if (tkls->offset() == mirror_field) { 2527 return adr2->in(AddPNode::Base); 2528 } 2529 } 2530 } 2531 } 2532 } 2533 2534 return this; 2535 } 2536 2537 2538 //------------------------------Value------------------------------------------ 2539 const Type* LoadNKlassNode::Value(PhaseGVN* phase) const { 2540 const Type *t = klass_value_common(phase); 2541 if (t == Type::TOP) 2542 return t; 2543 2544 return t->make_narrowklass(); 2545 } 2546 2547 //------------------------------Identity--------------------------------------- 2548 // To clean up reflective code, simplify k.java_mirror.as_klass to narrow k. 2549 // Also feed through the klass in Allocate(...klass...)._klass. 2550 Node* LoadNKlassNode::Identity(PhaseGVN* phase) { 2551 Node *x = klass_identity_common(phase); 2552 2553 const Type *t = phase->type( x ); 2554 if( t == Type::TOP ) return x; 2555 if( t->isa_narrowklass()) return x; 2556 assert (!t->isa_narrowoop(), "no narrow oop here"); 2557 2558 return phase->transform(new EncodePKlassNode(x, t->make_narrowklass())); 2559 } 2560 2561 //------------------------------Value----------------------------------------- 2562 const Type* LoadRangeNode::Value(PhaseGVN* phase) const { 2563 // Either input is TOP ==> the result is TOP 2564 const Type *t1 = phase->type( in(MemNode::Memory) ); 2565 if( t1 == Type::TOP ) return Type::TOP; 2566 Node *adr = in(MemNode::Address); 2567 const Type *t2 = phase->type( adr ); 2568 if( t2 == Type::TOP ) return Type::TOP; 2569 const TypePtr *tp = t2->is_ptr(); 2570 if (TypePtr::above_centerline(tp->ptr())) return Type::TOP; 2571 const TypeAryPtr *tap = tp->isa_aryptr(); 2572 if( !tap ) return _type; 2573 return tap->size(); 2574 } 2575 2576 //-------------------------------Ideal--------------------------------------- 2577 // Feed through the length in AllocateArray(...length...)._length. 2578 Node *LoadRangeNode::Ideal(PhaseGVN *phase, bool can_reshape) { 2579 Node* p = MemNode::Ideal_common(phase, can_reshape); 2580 if (p) return (p == NodeSentinel) ? NULL : p; 2581 2582 // Take apart the address into an oop and offset. 2583 // Return 'this' if we cannot. 2584 Node* adr = in(MemNode::Address); 2585 intptr_t offset = 0; 2586 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset); 2587 if (base == NULL) return NULL; 2588 const TypeAryPtr* tary = phase->type(adr)->isa_aryptr(); 2589 if (tary == NULL) return NULL; 2590 2591 // We can fetch the length directly through an AllocateArrayNode. 2592 // This works even if the length is not constant (clone or newArray). 2593 if (offset == arrayOopDesc::length_offset_in_bytes()) { 2594 AllocateArrayNode* alloc = AllocateArrayNode::Ideal_array_allocation(base, phase); 2595 if (alloc != NULL) { 2596 Node* allocated_length = alloc->Ideal_length(); 2597 Node* len = alloc->make_ideal_length(tary, phase); 2598 if (allocated_length != len) { 2599 // New CastII improves on this. 2600 return len; 2601 } 2602 } 2603 } 2604 2605 return NULL; 2606 } 2607 2608 //------------------------------Identity--------------------------------------- 2609 // Feed through the length in AllocateArray(...length...)._length. 2610 Node* LoadRangeNode::Identity(PhaseGVN* phase) { 2611 Node* x = LoadINode::Identity(phase); 2612 if (x != this) return x; 2613 2614 // Take apart the address into an oop and offset. 2615 // Return 'this' if we cannot. 2616 Node* adr = in(MemNode::Address); 2617 intptr_t offset = 0; 2618 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset); 2619 if (base == NULL) return this; 2620 const TypeAryPtr* tary = phase->type(adr)->isa_aryptr(); 2621 if (tary == NULL) return this; 2622 2623 // We can fetch the length directly through an AllocateArrayNode. 2624 // This works even if the length is not constant (clone or newArray). 2625 if (offset == arrayOopDesc::length_offset_in_bytes()) { 2626 AllocateArrayNode* alloc = AllocateArrayNode::Ideal_array_allocation(base, phase); 2627 if (alloc != NULL) { 2628 Node* allocated_length = alloc->Ideal_length(); 2629 // Do not allow make_ideal_length to allocate a CastII node. 2630 Node* len = alloc->make_ideal_length(tary, phase, false); 2631 if (allocated_length == len) { 2632 // Return allocated_length only if it would not be improved by a CastII. 2633 return allocated_length; 2634 } 2635 } 2636 } 2637 2638 return this; 2639 2640 } 2641 2642 //============================================================================= 2643 //---------------------------StoreNode::make----------------------------------- 2644 // Polymorphic factory method: 2645 StoreNode* StoreNode::make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, BasicType bt, MemOrd mo, bool require_atomic_access) { 2646 assert((mo == unordered || mo == release), "unexpected"); 2647 Compile* C = gvn.C; 2648 assert(C->get_alias_index(adr_type) != Compile::AliasIdxRaw || 2649 ctl != NULL, "raw memory operations should have control edge"); 2650 2651 switch (bt) { 2652 case T_BOOLEAN: val = gvn.transform(new AndINode(val, gvn.intcon(0x1))); // Fall through to T_BYTE case 2653 case T_BYTE: return new StoreBNode(ctl, mem, adr, adr_type, val, mo); 2654 case T_INT: return new StoreINode(ctl, mem, adr, adr_type, val, mo); 2655 case T_CHAR: 2656 case T_SHORT: return new StoreCNode(ctl, mem, adr, adr_type, val, mo); 2657 case T_LONG: return new StoreLNode(ctl, mem, adr, adr_type, val, mo, require_atomic_access); 2658 case T_FLOAT: return new StoreFNode(ctl, mem, adr, adr_type, val, mo); 2659 case T_DOUBLE: return new StoreDNode(ctl, mem, adr, adr_type, val, mo, require_atomic_access); 2660 case T_METADATA: 2661 case T_ADDRESS: 2662 case T_PRIMITIVE_OBJECT: 2663 case T_OBJECT: 2664 #ifdef _LP64 2665 if (adr->bottom_type()->is_ptr_to_narrowoop()) { 2666 val = gvn.transform(new EncodePNode(val, val->bottom_type()->make_narrowoop())); 2667 return new StoreNNode(ctl, mem, adr, adr_type, val, mo); 2668 } else if (adr->bottom_type()->is_ptr_to_narrowklass() || 2669 (UseCompressedClassPointers && val->bottom_type()->isa_klassptr() && 2670 adr->bottom_type()->isa_rawptr())) { 2671 val = gvn.transform(new EncodePKlassNode(val, val->bottom_type()->make_narrowklass())); 2672 return new StoreNKlassNode(ctl, mem, adr, adr_type, val, mo); 2673 } 2674 #endif 2675 { 2676 return new StorePNode(ctl, mem, adr, adr_type, val, mo); 2677 } 2678 default: 2679 ShouldNotReachHere(); 2680 return (StoreNode*)NULL; 2681 } 2682 } 2683 2684 //--------------------------bottom_type---------------------------------------- 2685 const Type *StoreNode::bottom_type() const { 2686 return Type::MEMORY; 2687 } 2688 2689 //------------------------------hash------------------------------------------- 2690 uint StoreNode::hash() const { 2691 // unroll addition of interesting fields 2692 //return (uintptr_t)in(Control) + (uintptr_t)in(Memory) + (uintptr_t)in(Address) + (uintptr_t)in(ValueIn); 2693 2694 // Since they are not commoned, do not hash them: 2695 return NO_HASH; 2696 } 2697 2698 //------------------------------Ideal------------------------------------------ 2699 // Change back-to-back Store(, p, x) -> Store(m, p, y) to Store(m, p, x). 2700 // When a store immediately follows a relevant allocation/initialization, 2701 // try to capture it into the initialization, or hoist it above. 2702 Node *StoreNode::Ideal(PhaseGVN *phase, bool can_reshape) { 2703 Node* p = MemNode::Ideal_common(phase, can_reshape); 2704 if (p) return (p == NodeSentinel) ? NULL : p; 2705 2706 Node* mem = in(MemNode::Memory); 2707 Node* address = in(MemNode::Address); 2708 Node* value = in(MemNode::ValueIn); 2709 // Back-to-back stores to same address? Fold em up. Generally 2710 // unsafe if I have intervening uses... Also disallowed for StoreCM 2711 // since they must follow each StoreP operation. Redundant StoreCMs 2712 // are eliminated just before matching in final_graph_reshape. 2713 if (phase->C->get_adr_type(phase->C->get_alias_index(adr_type())) != TypeAryPtr::INLINES) { 2714 Node* st = mem; 2715 // If Store 'st' has more than one use, we cannot fold 'st' away. 2716 // For example, 'st' might be the final state at a conditional 2717 // return. Or, 'st' might be used by some node which is live at 2718 // the same time 'st' is live, which might be unschedulable. So, 2719 // require exactly ONE user until such time as we clone 'mem' for 2720 // each of 'mem's uses (thus making the exactly-1-user-rule hold 2721 // true). 2722 while (st->is_Store() && st->outcnt() == 1 && st->Opcode() != Op_StoreCM) { 2723 // Looking at a dead closed cycle of memory? 2724 assert(st != st->in(MemNode::Memory), "dead loop in StoreNode::Ideal"); 2725 assert(Opcode() == st->Opcode() || 2726 st->Opcode() == Op_StoreVector || 2727 Opcode() == Op_StoreVector || 2728 st->Opcode() == Op_StoreVectorScatter || 2729 Opcode() == Op_StoreVectorScatter || 2730 phase->C->get_alias_index(adr_type()) == Compile::AliasIdxRaw || 2731 (Opcode() == Op_StoreL && st->Opcode() == Op_StoreI) || // expanded ClearArrayNode 2732 (Opcode() == Op_StoreI && st->Opcode() == Op_StoreL) || // initialization by arraycopy 2733 (Opcode() == Op_StoreL && st->Opcode() == Op_StoreN) || 2734 (is_mismatched_access() || st->as_Store()->is_mismatched_access()), 2735 "no mismatched stores, except on raw memory: %s %s", NodeClassNames[Opcode()], NodeClassNames[st->Opcode()]); 2736 2737 if (st->in(MemNode::Address)->eqv_uncast(address) && 2738 st->as_Store()->memory_size() <= this->memory_size()) { 2739 Node* use = st->raw_out(0); 2740 if (phase->is_IterGVN()) { 2741 phase->is_IterGVN()->rehash_node_delayed(use); 2742 } 2743 // It's OK to do this in the parser, since DU info is always accurate, 2744 // and the parser always refers to nodes via SafePointNode maps. 2745 use->set_req_X(MemNode::Memory, st->in(MemNode::Memory), phase); 2746 return this; 2747 } 2748 st = st->in(MemNode::Memory); 2749 } 2750 } 2751 2752 2753 // Capture an unaliased, unconditional, simple store into an initializer. 2754 // Or, if it is independent of the allocation, hoist it above the allocation. 2755 if (ReduceFieldZeroing && /*can_reshape &&*/ 2756 mem->is_Proj() && mem->in(0)->is_Initialize()) { 2757 InitializeNode* init = mem->in(0)->as_Initialize(); 2758 intptr_t offset = init->can_capture_store(this, phase, can_reshape); 2759 if (offset > 0) { 2760 Node* moved = init->capture_store(this, offset, phase, can_reshape); 2761 // If the InitializeNode captured me, it made a raw copy of me, 2762 // and I need to disappear. 2763 if (moved != NULL) { 2764 // %%% hack to ensure that Ideal returns a new node: 2765 mem = MergeMemNode::make(mem); 2766 return mem; // fold me away 2767 } 2768 } 2769 } 2770 2771 // Fold reinterpret cast into memory operation: 2772 // StoreX mem (MoveY2X v) => StoreY mem v 2773 if (value->is_Move()) { 2774 const Type* vt = value->in(1)->bottom_type(); 2775 if (has_reinterpret_variant(vt)) { 2776 if (phase->C->post_loop_opts_phase()) { 2777 return convert_to_reinterpret_store(*phase, value->in(1), vt); 2778 } else { 2779 phase->C->record_for_post_loop_opts_igvn(this); // attempt the transformation once loop opts are over 2780 } 2781 } 2782 } 2783 2784 return NULL; // No further progress 2785 } 2786 2787 //------------------------------Value----------------------------------------- 2788 const Type* StoreNode::Value(PhaseGVN* phase) const { 2789 // Either input is TOP ==> the result is TOP 2790 const Type *t1 = phase->type( in(MemNode::Memory) ); 2791 if( t1 == Type::TOP ) return Type::TOP; 2792 const Type *t2 = phase->type( in(MemNode::Address) ); 2793 if( t2 == Type::TOP ) return Type::TOP; 2794 const Type *t3 = phase->type( in(MemNode::ValueIn) ); 2795 if( t3 == Type::TOP ) return Type::TOP; 2796 return Type::MEMORY; 2797 } 2798 2799 //------------------------------Identity--------------------------------------- 2800 // Remove redundant stores: 2801 // Store(m, p, Load(m, p)) changes to m. 2802 // Store(, p, x) -> Store(m, p, x) changes to Store(m, p, x). 2803 Node* StoreNode::Identity(PhaseGVN* phase) { 2804 Node* mem = in(MemNode::Memory); 2805 Node* adr = in(MemNode::Address); 2806 Node* val = in(MemNode::ValueIn); 2807 2808 Node* result = this; 2809 2810 // Load then Store? Then the Store is useless 2811 if (val->is_Load() && 2812 val->in(MemNode::Address)->eqv_uncast(adr) && 2813 val->in(MemNode::Memory )->eqv_uncast(mem) && 2814 val->as_Load()->store_Opcode() == Opcode()) { 2815 result = mem; 2816 } 2817 2818 // Two stores in a row of the same value? 2819 if (result == this && 2820 mem->is_Store() && 2821 mem->in(MemNode::Address)->eqv_uncast(adr) && 2822 mem->in(MemNode::ValueIn)->eqv_uncast(val) && 2823 mem->Opcode() == Opcode()) { 2824 result = mem; 2825 } 2826 2827 // Store of zero anywhere into a freshly-allocated object? 2828 // Then the store is useless. 2829 // (It must already have been captured by the InitializeNode.) 2830 if (result == this && ReduceFieldZeroing) { 2831 // a newly allocated object is already all-zeroes everywhere 2832 if (mem->is_Proj() && mem->in(0)->is_Allocate() && 2833 (phase->type(val)->is_zero_type() || mem->in(0)->in(AllocateNode::DefaultValue) == val)) { 2834 result = mem; 2835 } 2836 2837 if (result == this && phase->type(val)->is_zero_type()) { 2838 // the store may also apply to zero-bits in an earlier object 2839 Node* prev_mem = find_previous_store(phase); 2840 // Steps (a), (b): Walk past independent stores to find an exact match. 2841 if (prev_mem != NULL) { 2842 Node* prev_val = can_see_stored_value(prev_mem, phase); 2843 if (prev_val != NULL && prev_val == val) { 2844 // prev_val and val might differ by a cast; it would be good 2845 // to keep the more informative of the two. 2846 result = mem; 2847 } 2848 } 2849 } 2850 } 2851 2852 PhaseIterGVN* igvn = phase->is_IterGVN(); 2853 if (result != this && igvn != NULL) { 2854 MemBarNode* trailing = trailing_membar(); 2855 if (trailing != NULL) { 2856 #ifdef ASSERT 2857 const TypeOopPtr* t_oop = phase->type(in(Address))->isa_oopptr(); 2858 assert(t_oop == NULL || t_oop->is_known_instance_field(), "only for non escaping objects"); 2859 #endif 2860 trailing->remove(igvn); 2861 } 2862 } 2863 2864 return result; 2865 } 2866 2867 //------------------------------match_edge------------------------------------- 2868 // Do we Match on this edge index or not? Match only memory & value 2869 uint StoreNode::match_edge(uint idx) const { 2870 return idx == MemNode::Address || idx == MemNode::ValueIn; 2871 } 2872 2873 //------------------------------cmp-------------------------------------------- 2874 // Do not common stores up together. They generally have to be split 2875 // back up anyways, so do not bother. 2876 bool StoreNode::cmp( const Node &n ) const { 2877 return (&n == this); // Always fail except on self 2878 } 2879 2880 //------------------------------Ideal_masked_input----------------------------- 2881 // Check for a useless mask before a partial-word store 2882 // (StoreB ... (AndI valIn conIa) ) 2883 // If (conIa & mask == mask) this simplifies to 2884 // (StoreB ... (valIn) ) 2885 Node *StoreNode::Ideal_masked_input(PhaseGVN *phase, uint mask) { 2886 Node *val = in(MemNode::ValueIn); 2887 if( val->Opcode() == Op_AndI ) { 2888 const TypeInt *t = phase->type( val->in(2) )->isa_int(); 2889 if( t && t->is_con() && (t->get_con() & mask) == mask ) { 2890 set_req_X(MemNode::ValueIn, val->in(1), phase); 2891 return this; 2892 } 2893 } 2894 return NULL; 2895 } 2896 2897 2898 //------------------------------Ideal_sign_extended_input---------------------- 2899 // Check for useless sign-extension before a partial-word store 2900 // (StoreB ... (RShiftI _ (LShiftI _ valIn conIL ) conIR) ) 2901 // If (conIL == conIR && conIR <= num_bits) this simplifies to 2902 // (StoreB ... (valIn) ) 2903 Node *StoreNode::Ideal_sign_extended_input(PhaseGVN *phase, int num_bits) { 2904 Node *val = in(MemNode::ValueIn); 2905 if( val->Opcode() == Op_RShiftI ) { 2906 const TypeInt *t = phase->type( val->in(2) )->isa_int(); 2907 if( t && t->is_con() && (t->get_con() <= num_bits) ) { 2908 Node *shl = val->in(1); 2909 if( shl->Opcode() == Op_LShiftI ) { 2910 const TypeInt *t2 = phase->type( shl->in(2) )->isa_int(); 2911 if( t2 && t2->is_con() && (t2->get_con() == t->get_con()) ) { 2912 set_req_X(MemNode::ValueIn, shl->in(1), phase); 2913 return this; 2914 } 2915 } 2916 } 2917 } 2918 return NULL; 2919 } 2920 2921 //------------------------------value_never_loaded----------------------------------- 2922 // Determine whether there are any possible loads of the value stored. 2923 // For simplicity, we actually check if there are any loads from the 2924 // address stored to, not just for loads of the value stored by this node. 2925 // 2926 bool StoreNode::value_never_loaded( PhaseTransform *phase) const { 2927 Node *adr = in(Address); 2928 const TypeOopPtr *adr_oop = phase->type(adr)->isa_oopptr(); 2929 if (adr_oop == NULL) 2930 return false; 2931 if (!adr_oop->is_known_instance_field()) 2932 return false; // if not a distinct instance, there may be aliases of the address 2933 for (DUIterator_Fast imax, i = adr->fast_outs(imax); i < imax; i++) { 2934 Node *use = adr->fast_out(i); 2935 if (use->is_Load() || use->is_LoadStore()) { 2936 return false; 2937 } 2938 } 2939 return true; 2940 } 2941 2942 MemBarNode* StoreNode::trailing_membar() const { 2943 if (is_release()) { 2944 MemBarNode* trailing_mb = NULL; 2945 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 2946 Node* u = fast_out(i); 2947 if (u->is_MemBar()) { 2948 if (u->as_MemBar()->trailing_store()) { 2949 assert(u->Opcode() == Op_MemBarVolatile, ""); 2950 assert(trailing_mb == NULL, "only one"); 2951 trailing_mb = u->as_MemBar(); 2952 #ifdef ASSERT 2953 Node* leading = u->as_MemBar()->leading_membar(); 2954 assert(leading->Opcode() == Op_MemBarRelease, "incorrect membar"); 2955 assert(leading->as_MemBar()->leading_store(), "incorrect membar pair"); 2956 assert(leading->as_MemBar()->trailing_membar() == u, "incorrect membar pair"); 2957 #endif 2958 } else { 2959 assert(u->as_MemBar()->standalone(), ""); 2960 } 2961 } 2962 } 2963 return trailing_mb; 2964 } 2965 return NULL; 2966 } 2967 2968 2969 //============================================================================= 2970 //------------------------------Ideal------------------------------------------ 2971 // If the store is from an AND mask that leaves the low bits untouched, then 2972 // we can skip the AND operation. If the store is from a sign-extension 2973 // (a left shift, then right shift) we can skip both. 2974 Node *StoreBNode::Ideal(PhaseGVN *phase, bool can_reshape){ 2975 Node *progress = StoreNode::Ideal_masked_input(phase, 0xFF); 2976 if( progress != NULL ) return progress; 2977 2978 progress = StoreNode::Ideal_sign_extended_input(phase, 24); 2979 if( progress != NULL ) return progress; 2980 2981 // Finally check the default case 2982 return StoreNode::Ideal(phase, can_reshape); 2983 } 2984 2985 //============================================================================= 2986 //------------------------------Ideal------------------------------------------ 2987 // If the store is from an AND mask that leaves the low bits untouched, then 2988 // we can skip the AND operation 2989 Node *StoreCNode::Ideal(PhaseGVN *phase, bool can_reshape){ 2990 Node *progress = StoreNode::Ideal_masked_input(phase, 0xFFFF); 2991 if( progress != NULL ) return progress; 2992 2993 progress = StoreNode::Ideal_sign_extended_input(phase, 16); 2994 if( progress != NULL ) return progress; 2995 2996 // Finally check the default case 2997 return StoreNode::Ideal(phase, can_reshape); 2998 } 2999 3000 //============================================================================= 3001 //------------------------------Identity--------------------------------------- 3002 Node* StoreCMNode::Identity(PhaseGVN* phase) { 3003 // No need to card mark when storing a null ptr 3004 Node* my_store = in(MemNode::OopStore); 3005 if (my_store->is_Store()) { 3006 const Type *t1 = phase->type( my_store->in(MemNode::ValueIn) ); 3007 if( t1 == TypePtr::NULL_PTR ) { 3008 return in(MemNode::Memory); 3009 } 3010 } 3011 return this; 3012 } 3013 3014 //============================================================================= 3015 //------------------------------Ideal--------------------------------------- 3016 Node *StoreCMNode::Ideal(PhaseGVN *phase, bool can_reshape){ 3017 Node* progress = StoreNode::Ideal(phase, can_reshape); 3018 if (progress != NULL) return progress; 3019 3020 Node* my_store = in(MemNode::OopStore); 3021 if (my_store->is_MergeMem()) { 3022 if (oop_alias_idx() != phase->C->get_alias_index(TypeAryPtr::INLINES) || 3023 phase->C->flattened_accesses_share_alias()) { 3024 // The alias that was recorded is no longer accurate enough. 3025 Node* mem = my_store->as_MergeMem()->memory_at(oop_alias_idx()); 3026 set_req_X(MemNode::OopStore, mem, phase); 3027 return this; 3028 } 3029 } 3030 3031 return NULL; 3032 } 3033 3034 //------------------------------Value----------------------------------------- 3035 const Type* StoreCMNode::Value(PhaseGVN* phase) const { 3036 // Either input is TOP ==> the result is TOP (checked in StoreNode::Value). 3037 // If extra input is TOP ==> the result is TOP 3038 const Type* t = phase->type(in(MemNode::OopStore)); 3039 if (t == Type::TOP) { 3040 return Type::TOP; 3041 } 3042 return StoreNode::Value(phase); 3043 } 3044 3045 3046 //============================================================================= 3047 //----------------------------------SCMemProjNode------------------------------ 3048 const Type* SCMemProjNode::Value(PhaseGVN* phase) const 3049 { 3050 if (in(0) == NULL || phase->type(in(0)) == Type::TOP) { 3051 return Type::TOP; 3052 } 3053 return bottom_type(); 3054 } 3055 3056 //============================================================================= 3057 //----------------------------------LoadStoreNode------------------------------ 3058 LoadStoreNode::LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required ) 3059 : Node(required), 3060 _type(rt), 3061 _adr_type(at), 3062 _barrier_data(0) 3063 { 3064 init_req(MemNode::Control, c ); 3065 init_req(MemNode::Memory , mem); 3066 init_req(MemNode::Address, adr); 3067 init_req(MemNode::ValueIn, val); 3068 init_class_id(Class_LoadStore); 3069 } 3070 3071 //------------------------------Value----------------------------------------- 3072 const Type* LoadStoreNode::Value(PhaseGVN* phase) const { 3073 // Either input is TOP ==> the result is TOP 3074 if (!in(MemNode::Control) || phase->type(in(MemNode::Control)) == Type::TOP) { 3075 return Type::TOP; 3076 } 3077 const Type* t = phase->type(in(MemNode::Memory)); 3078 if (t == Type::TOP) { 3079 return Type::TOP; 3080 } 3081 t = phase->type(in(MemNode::Address)); 3082 if (t == Type::TOP) { 3083 return Type::TOP; 3084 } 3085 t = phase->type(in(MemNode::ValueIn)); 3086 if (t == Type::TOP) { 3087 return Type::TOP; 3088 } 3089 return bottom_type(); 3090 } 3091 3092 uint LoadStoreNode::ideal_reg() const { 3093 return _type->ideal_reg(); 3094 } 3095 3096 bool LoadStoreNode::result_not_used() const { 3097 for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) { 3098 Node *x = fast_out(i); 3099 if (x->Opcode() == Op_SCMemProj) continue; 3100 return false; 3101 } 3102 return true; 3103 } 3104 3105 MemBarNode* LoadStoreNode::trailing_membar() const { 3106 MemBarNode* trailing = NULL; 3107 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) { 3108 Node* u = fast_out(i); 3109 if (u->is_MemBar()) { 3110 if (u->as_MemBar()->trailing_load_store()) { 3111 assert(u->Opcode() == Op_MemBarAcquire, ""); 3112 assert(trailing == NULL, "only one"); 3113 trailing = u->as_MemBar(); 3114 #ifdef ASSERT 3115 Node* leading = trailing->leading_membar(); 3116 assert(support_IRIW_for_not_multiple_copy_atomic_cpu || leading->Opcode() == Op_MemBarRelease, "incorrect membar"); 3117 assert(leading->as_MemBar()->leading_load_store(), "incorrect membar pair"); 3118 assert(leading->as_MemBar()->trailing_membar() == trailing, "incorrect membar pair"); 3119 #endif 3120 } else { 3121 assert(u->as_MemBar()->standalone(), "wrong barrier kind"); 3122 } 3123 } 3124 } 3125 3126 return trailing; 3127 } 3128 3129 uint LoadStoreNode::size_of() const { return sizeof(*this); } 3130 3131 //============================================================================= 3132 //----------------------------------LoadStoreConditionalNode-------------------- 3133 LoadStoreConditionalNode::LoadStoreConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex ) : LoadStoreNode(c, mem, adr, val, NULL, TypeInt::BOOL, 5) { 3134 init_req(ExpectedIn, ex ); 3135 } 3136 3137 const Type* LoadStoreConditionalNode::Value(PhaseGVN* phase) const { 3138 // Either input is TOP ==> the result is TOP 3139 const Type* t = phase->type(in(ExpectedIn)); 3140 if (t == Type::TOP) { 3141 return Type::TOP; 3142 } 3143 return LoadStoreNode::Value(phase); 3144 } 3145 3146 //============================================================================= 3147 //-------------------------------adr_type-------------------------------------- 3148 const TypePtr* ClearArrayNode::adr_type() const { 3149 Node *adr = in(3); 3150 if (adr == NULL) return NULL; // node is dead 3151 return MemNode::calculate_adr_type(adr->bottom_type()); 3152 } 3153 3154 //------------------------------match_edge------------------------------------- 3155 // Do we Match on this edge index or not? Do not match memory 3156 uint ClearArrayNode::match_edge(uint idx) const { 3157 return idx > 1; 3158 } 3159 3160 //------------------------------Identity--------------------------------------- 3161 // Clearing a zero length array does nothing 3162 Node* ClearArrayNode::Identity(PhaseGVN* phase) { 3163 return phase->type(in(2))->higher_equal(TypeX::ZERO) ? in(1) : this; 3164 } 3165 3166 //------------------------------Idealize--------------------------------------- 3167 // Clearing a short array is faster with stores 3168 Node *ClearArrayNode::Ideal(PhaseGVN *phase, bool can_reshape) { 3169 // Already know this is a large node, do not try to ideal it 3170 if (_is_large) return NULL; 3171 3172 const int unit = BytesPerLong; 3173 const TypeX* t = phase->type(in(2))->isa_intptr_t(); 3174 if (!t) return NULL; 3175 if (!t->is_con()) return NULL; 3176 intptr_t raw_count = t->get_con(); 3177 intptr_t size = raw_count; 3178 if (!Matcher::init_array_count_is_in_bytes) size *= unit; 3179 // Clearing nothing uses the Identity call. 3180 // Negative clears are possible on dead ClearArrays 3181 // (see jck test stmt114.stmt11402.val). 3182 if (size <= 0 || size % unit != 0) return NULL; 3183 intptr_t count = size / unit; 3184 // Length too long; communicate this to matchers and assemblers. 3185 // Assemblers are responsible to produce fast hardware clears for it. 3186 if (size > InitArrayShortSize) { 3187 return new ClearArrayNode(in(0), in(1), in(2), in(3), in(4), true); 3188 } else if (size > 2 && Matcher::match_rule_supported_vector(Op_ClearArray, 4, T_LONG)) { 3189 return NULL; 3190 } 3191 if (!IdealizeClearArrayNode) return NULL; 3192 Node *mem = in(1); 3193 if( phase->type(mem)==Type::TOP ) return NULL; 3194 Node *adr = in(3); 3195 const Type* at = phase->type(adr); 3196 if( at==Type::TOP ) return NULL; 3197 const TypePtr* atp = at->isa_ptr(); 3198 // adjust atp to be the correct array element address type 3199 if (atp == NULL) atp = TypePtr::BOTTOM; 3200 else atp = atp->add_offset(Type::OffsetBot); 3201 // Get base for derived pointer purposes 3202 if( adr->Opcode() != Op_AddP ) Unimplemented(); 3203 Node *base = adr->in(1); 3204 3205 Node *val = in(4); 3206 Node *off = phase->MakeConX(BytesPerLong); 3207 mem = new StoreLNode(in(0), mem, adr, atp, val, MemNode::unordered, false); 3208 count--; 3209 while( count-- ) { 3210 mem = phase->transform(mem); 3211 adr = phase->transform(new AddPNode(base,adr,off)); 3212 mem = new StoreLNode(in(0), mem, adr, atp, val, MemNode::unordered, false); 3213 } 3214 return mem; 3215 } 3216 3217 //----------------------------step_through---------------------------------- 3218 // Return allocation input memory edge if it is different instance 3219 // or itself if it is the one we are looking for. 3220 bool ClearArrayNode::step_through(Node** np, uint instance_id, PhaseTransform* phase) { 3221 Node* n = *np; 3222 assert(n->is_ClearArray(), "sanity"); 3223 intptr_t offset; 3224 AllocateNode* alloc = AllocateNode::Ideal_allocation(n->in(3), phase, offset); 3225 // This method is called only before Allocate nodes are expanded 3226 // during macro nodes expansion. Before that ClearArray nodes are 3227 // only generated in PhaseMacroExpand::generate_arraycopy() (before 3228 // Allocate nodes are expanded) which follows allocations. 3229 assert(alloc != NULL, "should have allocation"); 3230 if (alloc->_idx == instance_id) { 3231 // Can not bypass initialization of the instance we are looking for. 3232 return false; 3233 } 3234 // Otherwise skip it. 3235 InitializeNode* init = alloc->initialization(); 3236 if (init != NULL) 3237 *np = init->in(TypeFunc::Memory); 3238 else 3239 *np = alloc->in(TypeFunc::Memory); 3240 return true; 3241 } 3242 3243 //----------------------------clear_memory------------------------------------- 3244 // Generate code to initialize object storage to zero. 3245 Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest, 3246 Node* val, 3247 Node* raw_val, 3248 intptr_t start_offset, 3249 Node* end_offset, 3250 PhaseGVN* phase) { 3251 intptr_t offset = start_offset; 3252 3253 int unit = BytesPerLong; 3254 if ((offset % unit) != 0) { 3255 Node* adr = new AddPNode(dest, dest, phase->MakeConX(offset)); 3256 adr = phase->transform(adr); 3257 const TypePtr* atp = TypeRawPtr::BOTTOM; 3258 if (val != NULL) { 3259 assert(phase->type(val)->isa_narrowoop(), "should be narrow oop"); 3260 mem = new StoreNNode(ctl, mem, adr, atp, val, MemNode::unordered); 3261 } else { 3262 assert(raw_val == NULL, "val may not be null"); 3263 mem = StoreNode::make(*phase, ctl, mem, adr, atp, phase->zerocon(T_INT), T_INT, MemNode::unordered); 3264 } 3265 mem = phase->transform(mem); 3266 offset += BytesPerInt; 3267 } 3268 assert((offset % unit) == 0, ""); 3269 3270 // Initialize the remaining stuff, if any, with a ClearArray. 3271 return clear_memory(ctl, mem, dest, raw_val, phase->MakeConX(offset), end_offset, phase); 3272 } 3273 3274 Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest, 3275 Node* raw_val, 3276 Node* start_offset, 3277 Node* end_offset, 3278 PhaseGVN* phase) { 3279 if (start_offset == end_offset) { 3280 // nothing to do 3281 return mem; 3282 } 3283 3284 int unit = BytesPerLong; 3285 Node* zbase = start_offset; 3286 Node* zend = end_offset; 3287 3288 // Scale to the unit required by the CPU: 3289 if (!Matcher::init_array_count_is_in_bytes) { 3290 Node* shift = phase->intcon(exact_log2(unit)); 3291 zbase = phase->transform(new URShiftXNode(zbase, shift) ); 3292 zend = phase->transform(new URShiftXNode(zend, shift) ); 3293 } 3294 3295 // Bulk clear double-words 3296 Node* zsize = phase->transform(new SubXNode(zend, zbase) ); 3297 Node* adr = phase->transform(new AddPNode(dest, dest, start_offset) ); 3298 if (raw_val == NULL) { 3299 raw_val = phase->MakeConX(0); 3300 } 3301 mem = new ClearArrayNode(ctl, mem, zsize, adr, raw_val, false); 3302 return phase->transform(mem); 3303 } 3304 3305 Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest, 3306 Node* val, 3307 Node* raw_val, 3308 intptr_t start_offset, 3309 intptr_t end_offset, 3310 PhaseGVN* phase) { 3311 if (start_offset == end_offset) { 3312 // nothing to do 3313 return mem; 3314 } 3315 3316 assert((end_offset % BytesPerInt) == 0, "odd end offset"); 3317 intptr_t done_offset = end_offset; 3318 if ((done_offset % BytesPerLong) != 0) { 3319 done_offset -= BytesPerInt; 3320 } 3321 if (done_offset > start_offset) { 3322 mem = clear_memory(ctl, mem, dest, val, raw_val, 3323 start_offset, phase->MakeConX(done_offset), phase); 3324 } 3325 if (done_offset < end_offset) { // emit the final 32-bit store 3326 Node* adr = new AddPNode(dest, dest, phase->MakeConX(done_offset)); 3327 adr = phase->transform(adr); 3328 const TypePtr* atp = TypeRawPtr::BOTTOM; 3329 if (val != NULL) { 3330 assert(phase->type(val)->isa_narrowoop(), "should be narrow oop"); 3331 mem = new StoreNNode(ctl, mem, adr, atp, val, MemNode::unordered); 3332 } else { 3333 assert(raw_val == NULL, "val may not be null"); 3334 mem = StoreNode::make(*phase, ctl, mem, adr, atp, phase->zerocon(T_INT), T_INT, MemNode::unordered); 3335 } 3336 mem = phase->transform(mem); 3337 done_offset += BytesPerInt; 3338 } 3339 assert(done_offset == end_offset, ""); 3340 return mem; 3341 } 3342 3343 //============================================================================= 3344 MemBarNode::MemBarNode(Compile* C, int alias_idx, Node* precedent) 3345 : MultiNode(TypeFunc::Parms + (precedent == NULL? 0: 1)), 3346 _adr_type(C->get_adr_type(alias_idx)), _kind(Standalone) 3347 #ifdef ASSERT 3348 , _pair_idx(0) 3349 #endif 3350 { 3351 init_class_id(Class_MemBar); 3352 Node* top = C->top(); 3353 init_req(TypeFunc::I_O,top); 3354 init_req(TypeFunc::FramePtr,top); 3355 init_req(TypeFunc::ReturnAdr,top); 3356 if (precedent != NULL) 3357 init_req(TypeFunc::Parms, precedent); 3358 } 3359 3360 //------------------------------cmp-------------------------------------------- 3361 uint MemBarNode::hash() const { return NO_HASH; } 3362 bool MemBarNode::cmp( const Node &n ) const { 3363 return (&n == this); // Always fail except on self 3364 } 3365 3366 //------------------------------make------------------------------------------- 3367 MemBarNode* MemBarNode::make(Compile* C, int opcode, int atp, Node* pn) { 3368 switch (opcode) { 3369 case Op_MemBarAcquire: return new MemBarAcquireNode(C, atp, pn); 3370 case Op_LoadFence: return new LoadFenceNode(C, atp, pn); 3371 case Op_MemBarRelease: return new MemBarReleaseNode(C, atp, pn); 3372 case Op_StoreFence: return new StoreFenceNode(C, atp, pn); 3373 case Op_MemBarStoreStore: return new MemBarStoreStoreNode(C, atp, pn); 3374 case Op_StoreStoreFence: return new StoreStoreFenceNode(C, atp, pn); 3375 case Op_MemBarAcquireLock: return new MemBarAcquireLockNode(C, atp, pn); 3376 case Op_MemBarReleaseLock: return new MemBarReleaseLockNode(C, atp, pn); 3377 case Op_MemBarVolatile: return new MemBarVolatileNode(C, atp, pn); 3378 case Op_MemBarCPUOrder: return new MemBarCPUOrderNode(C, atp, pn); 3379 case Op_OnSpinWait: return new OnSpinWaitNode(C, atp, pn); 3380 case Op_Initialize: return new InitializeNode(C, atp, pn); 3381 default: ShouldNotReachHere(); return NULL; 3382 } 3383 } 3384 3385 void MemBarNode::remove(PhaseIterGVN *igvn) { 3386 if (outcnt() != 2) { 3387 assert(Opcode() == Op_Initialize, "Only seen when there are no use of init memory"); 3388 assert(outcnt() == 1, "Only control then"); 3389 } 3390 if (trailing_store() || trailing_load_store()) { 3391 MemBarNode* leading = leading_membar(); 3392 if (leading != NULL) { 3393 assert(leading->trailing_membar() == this, "inconsistent leading/trailing membars"); 3394 leading->remove(igvn); 3395 } 3396 } 3397 if (proj_out_or_null(TypeFunc::Memory) != NULL) { 3398 igvn->replace_node(proj_out(TypeFunc::Memory), in(TypeFunc::Memory)); 3399 } 3400 if (proj_out_or_null(TypeFunc::Control) != NULL) { 3401 igvn->replace_node(proj_out(TypeFunc::Control), in(TypeFunc::Control)); 3402 } 3403 } 3404 3405 //------------------------------Ideal------------------------------------------ 3406 // Return a node which is more "ideal" than the current node. Strip out 3407 // control copies 3408 Node *MemBarNode::Ideal(PhaseGVN *phase, bool can_reshape) { 3409 if (remove_dead_region(phase, can_reshape)) return this; 3410 // Don't bother trying to transform a dead node 3411 if (in(0) && in(0)->is_top()) { 3412 return NULL; 3413 } 3414 3415 bool progress = false; 3416 // Eliminate volatile MemBars for scalar replaced objects. 3417 if (can_reshape && req() == (Precedent+1)) { 3418 bool eliminate = false; 3419 int opc = Opcode(); 3420 if ((opc == Op_MemBarAcquire || opc == Op_MemBarVolatile)) { 3421 // Volatile field loads and stores. 3422 Node* my_mem = in(MemBarNode::Precedent); 3423 // The MembarAquire may keep an unused LoadNode alive through the Precedent edge 3424 if ((my_mem != NULL) && (opc == Op_MemBarAcquire) && (my_mem->outcnt() == 1)) { 3425 // if the Precedent is a decodeN and its input (a Load) is used at more than one place, 3426 // replace this Precedent (decodeN) with the Load instead. 3427 if ((my_mem->Opcode() == Op_DecodeN) && (my_mem->in(1)->outcnt() > 1)) { 3428 Node* load_node = my_mem->in(1); 3429 set_req(MemBarNode::Precedent, load_node); 3430 phase->is_IterGVN()->_worklist.push(my_mem); 3431 my_mem = load_node; 3432 } else { 3433 assert(my_mem->unique_out() == this, "sanity"); 3434 del_req(Precedent); 3435 phase->is_IterGVN()->_worklist.push(my_mem); // remove dead node later 3436 my_mem = NULL; 3437 } 3438 progress = true; 3439 } 3440 if (my_mem != NULL && my_mem->is_Mem()) { 3441 const TypeOopPtr* t_oop = my_mem->in(MemNode::Address)->bottom_type()->isa_oopptr(); 3442 // Check for scalar replaced object reference. 3443 if( t_oop != NULL && t_oop->is_known_instance_field() && 3444 t_oop->offset() != Type::OffsetBot && 3445 t_oop->offset() != Type::OffsetTop) { 3446 eliminate = true; 3447 } 3448 } 3449 } else if (opc == Op_MemBarRelease) { 3450 // Final field stores. 3451 Node* alloc = AllocateNode::Ideal_allocation(in(MemBarNode::Precedent), phase); 3452 if ((alloc != NULL) && alloc->is_Allocate() && 3453 alloc->as_Allocate()->does_not_escape_thread()) { 3454 // The allocated object does not escape. 3455 eliminate = true; 3456 } 3457 } 3458 if (eliminate) { 3459 // Replace MemBar projections by its inputs. 3460 PhaseIterGVN* igvn = phase->is_IterGVN(); 3461 remove(igvn); 3462 // Must return either the original node (now dead) or a new node 3463 // (Do not return a top here, since that would break the uniqueness of top.) 3464 return new ConINode(TypeInt::ZERO); 3465 } 3466 } 3467 return progress ? this : NULL; 3468 } 3469 3470 //------------------------------Value------------------------------------------ 3471 const Type* MemBarNode::Value(PhaseGVN* phase) const { 3472 if( !in(0) ) return Type::TOP; 3473 if( phase->type(in(0)) == Type::TOP ) 3474 return Type::TOP; 3475 return TypeTuple::MEMBAR; 3476 } 3477 3478 //------------------------------match------------------------------------------ 3479 // Construct projections for memory. 3480 Node *MemBarNode::match(const ProjNode *proj, const Matcher *m, const RegMask* mask) { 3481 switch (proj->_con) { 3482 case TypeFunc::Control: 3483 case TypeFunc::Memory: 3484 return new MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj); 3485 } 3486 ShouldNotReachHere(); 3487 return NULL; 3488 } 3489 3490 void MemBarNode::set_store_pair(MemBarNode* leading, MemBarNode* trailing) { 3491 trailing->_kind = TrailingStore; 3492 leading->_kind = LeadingStore; 3493 #ifdef ASSERT 3494 trailing->_pair_idx = leading->_idx; 3495 leading->_pair_idx = leading->_idx; 3496 #endif 3497 } 3498 3499 void MemBarNode::set_load_store_pair(MemBarNode* leading, MemBarNode* trailing) { 3500 trailing->_kind = TrailingLoadStore; 3501 leading->_kind = LeadingLoadStore; 3502 #ifdef ASSERT 3503 trailing->_pair_idx = leading->_idx; 3504 leading->_pair_idx = leading->_idx; 3505 #endif 3506 } 3507 3508 MemBarNode* MemBarNode::trailing_membar() const { 3509 ResourceMark rm; 3510 Node* trailing = (Node*)this; 3511 VectorSet seen; 3512 Node_Stack multis(0); 3513 do { 3514 Node* c = trailing; 3515 uint i = 0; 3516 do { 3517 trailing = NULL; 3518 for (; i < c->outcnt(); i++) { 3519 Node* next = c->raw_out(i); 3520 if (next != c && next->is_CFG()) { 3521 if (c->is_MultiBranch()) { 3522 if (multis.node() == c) { 3523 multis.set_index(i+1); 3524 } else { 3525 multis.push(c, i+1); 3526 } 3527 } 3528 trailing = next; 3529 break; 3530 } 3531 } 3532 if (trailing != NULL && !seen.test_set(trailing->_idx)) { 3533 break; 3534 } 3535 while (multis.size() > 0) { 3536 c = multis.node(); 3537 i = multis.index(); 3538 if (i < c->req()) { 3539 break; 3540 } 3541 multis.pop(); 3542 } 3543 } while (multis.size() > 0); 3544 } while (!trailing->is_MemBar() || !trailing->as_MemBar()->trailing()); 3545 3546 MemBarNode* mb = trailing->as_MemBar(); 3547 assert((mb->_kind == TrailingStore && _kind == LeadingStore) || 3548 (mb->_kind == TrailingLoadStore && _kind == LeadingLoadStore), "bad trailing membar"); 3549 assert(mb->_pair_idx == _pair_idx, "bad trailing membar"); 3550 return mb; 3551 } 3552 3553 MemBarNode* MemBarNode::leading_membar() const { 3554 ResourceMark rm; 3555 VectorSet seen; 3556 Node_Stack regions(0); 3557 Node* leading = in(0); 3558 while (leading != NULL && (!leading->is_MemBar() || !leading->as_MemBar()->leading())) { 3559 while (leading == NULL || leading->is_top() || seen.test_set(leading->_idx)) { 3560 leading = NULL; 3561 while (regions.size() > 0 && leading == NULL) { 3562 Node* r = regions.node(); 3563 uint i = regions.index(); 3564 if (i < r->req()) { 3565 leading = r->in(i); 3566 regions.set_index(i+1); 3567 } else { 3568 regions.pop(); 3569 } 3570 } 3571 if (leading == NULL) { 3572 assert(regions.size() == 0, "all paths should have been tried"); 3573 return NULL; 3574 } 3575 } 3576 if (leading->is_Region()) { 3577 regions.push(leading, 2); 3578 leading = leading->in(1); 3579 } else { 3580 leading = leading->in(0); 3581 } 3582 } 3583 #ifdef ASSERT 3584 Unique_Node_List wq; 3585 wq.push((Node*)this); 3586 uint found = 0; 3587 for (uint i = 0; i < wq.size(); i++) { 3588 Node* n = wq.at(i); 3589 if (n->is_Region()) { 3590 for (uint j = 1; j < n->req(); j++) { 3591 Node* in = n->in(j); 3592 if (in != NULL && !in->is_top()) { 3593 wq.push(in); 3594 } 3595 } 3596 } else { 3597 if (n->is_MemBar() && n->as_MemBar()->leading()) { 3598 assert(n == leading, "consistency check failed"); 3599 found++; 3600 } else { 3601 Node* in = n->in(0); 3602 if (in != NULL && !in->is_top()) { 3603 wq.push(in); 3604 } 3605 } 3606 } 3607 } 3608 assert(found == 1 || (found == 0 && leading == NULL), "consistency check failed"); 3609 #endif 3610 if (leading == NULL) { 3611 return NULL; 3612 } 3613 MemBarNode* mb = leading->as_MemBar(); 3614 assert((mb->_kind == LeadingStore && _kind == TrailingStore) || 3615 (mb->_kind == LeadingLoadStore && _kind == TrailingLoadStore), "bad leading membar"); 3616 assert(mb->_pair_idx == _pair_idx, "bad leading membar"); 3617 return mb; 3618 } 3619 3620 3621 //===========================InitializeNode==================================== 3622 // SUMMARY: 3623 // This node acts as a memory barrier on raw memory, after some raw stores. 3624 // The 'cooked' oop value feeds from the Initialize, not the Allocation. 3625 // The Initialize can 'capture' suitably constrained stores as raw inits. 3626 // It can coalesce related raw stores into larger units (called 'tiles'). 3627 // It can avoid zeroing new storage for memory units which have raw inits. 3628 // At macro-expansion, it is marked 'complete', and does not optimize further. 3629 // 3630 // EXAMPLE: 3631 // The object 'new short[2]' occupies 16 bytes in a 32-bit machine. 3632 // ctl = incoming control; mem* = incoming memory 3633 // (Note: A star * on a memory edge denotes I/O and other standard edges.) 3634 // First allocate uninitialized memory and fill in the header: 3635 // alloc = (Allocate ctl mem* 16 #short[].klass ...) 3636 // ctl := alloc.Control; mem* := alloc.Memory* 3637 // rawmem = alloc.Memory; rawoop = alloc.RawAddress 3638 // Then initialize to zero the non-header parts of the raw memory block: 3639 // init = (Initialize alloc.Control alloc.Memory* alloc.RawAddress) 3640 // ctl := init.Control; mem.SLICE(#short[*]) := init.Memory 3641 // After the initialize node executes, the object is ready for service: 3642 // oop := (CheckCastPP init.Control alloc.RawAddress #short[]) 3643 // Suppose its body is immediately initialized as {1,2}: 3644 // store1 = (StoreC init.Control init.Memory (+ oop 12) 1) 3645 // store2 = (StoreC init.Control store1 (+ oop 14) 2) 3646 // mem.SLICE(#short[*]) := store2 3647 // 3648 // DETAILS: 3649 // An InitializeNode collects and isolates object initialization after 3650 // an AllocateNode and before the next possible safepoint. As a 3651 // memory barrier (MemBarNode), it keeps critical stores from drifting 3652 // down past any safepoint or any publication of the allocation. 3653 // Before this barrier, a newly-allocated object may have uninitialized bits. 3654 // After this barrier, it may be treated as a real oop, and GC is allowed. 3655 // 3656 // The semantics of the InitializeNode include an implicit zeroing of 3657 // the new object from object header to the end of the object. 3658 // (The object header and end are determined by the AllocateNode.) 3659 // 3660 // Certain stores may be added as direct inputs to the InitializeNode. 3661 // These stores must update raw memory, and they must be to addresses 3662 // derived from the raw address produced by AllocateNode, and with 3663 // a constant offset. They must be ordered by increasing offset. 3664 // The first one is at in(RawStores), the last at in(req()-1). 3665 // Unlike most memory operations, they are not linked in a chain, 3666 // but are displayed in parallel as users of the rawmem output of 3667 // the allocation. 3668 // 3669 // (See comments in InitializeNode::capture_store, which continue 3670 // the example given above.) 3671 // 3672 // When the associated Allocate is macro-expanded, the InitializeNode 3673 // may be rewritten to optimize collected stores. A ClearArrayNode 3674 // may also be created at that point to represent any required zeroing. 3675 // The InitializeNode is then marked 'complete', prohibiting further 3676 // capturing of nearby memory operations. 3677 // 3678 // During macro-expansion, all captured initializations which store 3679 // constant values of 32 bits or smaller are coalesced (if advantageous) 3680 // into larger 'tiles' 32 or 64 bits. This allows an object to be 3681 // initialized in fewer memory operations. Memory words which are 3682 // covered by neither tiles nor non-constant stores are pre-zeroed 3683 // by explicit stores of zero. (The code shape happens to do all 3684 // zeroing first, then all other stores, with both sequences occurring 3685 // in order of ascending offsets.) 3686 // 3687 // Alternatively, code may be inserted between an AllocateNode and its 3688 // InitializeNode, to perform arbitrary initialization of the new object. 3689 // E.g., the object copying intrinsics insert complex data transfers here. 3690 // The initialization must then be marked as 'complete' disable the 3691 // built-in zeroing semantics and the collection of initializing stores. 3692 // 3693 // While an InitializeNode is incomplete, reads from the memory state 3694 // produced by it are optimizable if they match the control edge and 3695 // new oop address associated with the allocation/initialization. 3696 // They return a stored value (if the offset matches) or else zero. 3697 // A write to the memory state, if it matches control and address, 3698 // and if it is to a constant offset, may be 'captured' by the 3699 // InitializeNode. It is cloned as a raw memory operation and rewired 3700 // inside the initialization, to the raw oop produced by the allocation. 3701 // Operations on addresses which are provably distinct (e.g., to 3702 // other AllocateNodes) are allowed to bypass the initialization. 3703 // 3704 // The effect of all this is to consolidate object initialization 3705 // (both arrays and non-arrays, both piecewise and bulk) into a 3706 // single location, where it can be optimized as a unit. 3707 // 3708 // Only stores with an offset less than TrackedInitializationLimit words 3709 // will be considered for capture by an InitializeNode. This puts a 3710 // reasonable limit on the complexity of optimized initializations. 3711 3712 //---------------------------InitializeNode------------------------------------ 3713 InitializeNode::InitializeNode(Compile* C, int adr_type, Node* rawoop) 3714 : MemBarNode(C, adr_type, rawoop), 3715 _is_complete(Incomplete), _does_not_escape(false) 3716 { 3717 init_class_id(Class_Initialize); 3718 3719 assert(adr_type == Compile::AliasIdxRaw, "only valid atp"); 3720 assert(in(RawAddress) == rawoop, "proper init"); 3721 // Note: allocation() can be NULL, for secondary initialization barriers 3722 } 3723 3724 // Since this node is not matched, it will be processed by the 3725 // register allocator. Declare that there are no constraints 3726 // on the allocation of the RawAddress edge. 3727 const RegMask &InitializeNode::in_RegMask(uint idx) const { 3728 // This edge should be set to top, by the set_complete. But be conservative. 3729 if (idx == InitializeNode::RawAddress) 3730 return *(Compile::current()->matcher()->idealreg2spillmask[in(idx)->ideal_reg()]); 3731 return RegMask::Empty; 3732 } 3733 3734 Node* InitializeNode::memory(uint alias_idx) { 3735 Node* mem = in(Memory); 3736 if (mem->is_MergeMem()) { 3737 return mem->as_MergeMem()->memory_at(alias_idx); 3738 } else { 3739 // incoming raw memory is not split 3740 return mem; 3741 } 3742 } 3743 3744 bool InitializeNode::is_non_zero() { 3745 if (is_complete()) return false; 3746 remove_extra_zeroes(); 3747 return (req() > RawStores); 3748 } 3749 3750 void InitializeNode::set_complete(PhaseGVN* phase) { 3751 assert(!is_complete(), "caller responsibility"); 3752 _is_complete = Complete; 3753 3754 // After this node is complete, it contains a bunch of 3755 // raw-memory initializations. There is no need for 3756 // it to have anything to do with non-raw memory effects. 3757 // Therefore, tell all non-raw users to re-optimize themselves, 3758 // after skipping the memory effects of this initialization. 3759 PhaseIterGVN* igvn = phase->is_IterGVN(); 3760 if (igvn) igvn->add_users_to_worklist(this); 3761 } 3762 3763 // convenience function 3764 // return false if the init contains any stores already 3765 bool AllocateNode::maybe_set_complete(PhaseGVN* phase) { 3766 InitializeNode* init = initialization(); 3767 if (init == NULL || init->is_complete()) { 3768 return false; 3769 } 3770 init->remove_extra_zeroes(); 3771 // for now, if this allocation has already collected any inits, bail: 3772 if (init->is_non_zero()) return false; 3773 init->set_complete(phase); 3774 return true; 3775 } 3776 3777 void InitializeNode::remove_extra_zeroes() { 3778 if (req() == RawStores) return; 3779 Node* zmem = zero_memory(); 3780 uint fill = RawStores; 3781 for (uint i = fill; i < req(); i++) { 3782 Node* n = in(i); 3783 if (n->is_top() || n == zmem) continue; // skip 3784 if (fill < i) set_req(fill, n); // compact 3785 ++fill; 3786 } 3787 // delete any empty spaces created: 3788 while (fill < req()) { 3789 del_req(fill); 3790 } 3791 } 3792 3793 // Helper for remembering which stores go with which offsets. 3794 intptr_t InitializeNode::get_store_offset(Node* st, PhaseTransform* phase) { 3795 if (!st->is_Store()) return -1; // can happen to dead code via subsume_node 3796 intptr_t offset = -1; 3797 Node* base = AddPNode::Ideal_base_and_offset(st->in(MemNode::Address), 3798 phase, offset); 3799 if (base == NULL) return -1; // something is dead, 3800 if (offset < 0) return -1; // dead, dead 3801 return offset; 3802 } 3803 3804 // Helper for proving that an initialization expression is 3805 // "simple enough" to be folded into an object initialization. 3806 // Attempts to prove that a store's initial value 'n' can be captured 3807 // within the initialization without creating a vicious cycle, such as: 3808 // { Foo p = new Foo(); p.next = p; } 3809 // True for constants and parameters and small combinations thereof. 3810 bool InitializeNode::detect_init_independence(Node* value, PhaseGVN* phase) { 3811 ResourceMark rm; 3812 Unique_Node_List worklist; 3813 worklist.push(value); 3814 3815 uint complexity_limit = 20; 3816 for (uint j = 0; j < worklist.size(); j++) { 3817 if (j >= complexity_limit) { 3818 return false; // Bail out if processed too many nodes 3819 } 3820 3821 Node* n = worklist.at(j); 3822 if (n == NULL) continue; // (can this really happen?) 3823 if (n->is_Proj()) n = n->in(0); 3824 if (n == this) return false; // found a cycle 3825 if (n->is_Con()) continue; 3826 if (n->is_Start()) continue; // params, etc., are OK 3827 if (n->is_Root()) continue; // even better 3828 3829 // There cannot be any dependency if 'n' is a CFG node that dominates the current allocation 3830 if (n->is_CFG() && phase->is_dominator(n, allocation())) { 3831 continue; 3832 } 3833 3834 Node* ctl = n->in(0); 3835 if (ctl != NULL && !ctl->is_top()) { 3836 if (ctl->is_Proj()) ctl = ctl->in(0); 3837 if (ctl == this) return false; 3838 3839 // If we already know that the enclosing memory op is pinned right after 3840 // the init, then any control flow that the store has picked up 3841 // must have preceded the init, or else be equal to the init. 3842 // Even after loop optimizations (which might change control edges) 3843 // a store is never pinned *before* the availability of its inputs. 3844 if (!MemNode::all_controls_dominate(n, this)) 3845 return false; // failed to prove a good control 3846 } 3847 3848 // Check data edges for possible dependencies on 'this'. 3849 for (uint i = 1; i < n->req(); i++) { 3850 Node* m = n->in(i); 3851 if (m == NULL || m == n || m->is_top()) continue; 3852 3853 // Only process data inputs once 3854 worklist.push(m); 3855 } 3856 } 3857 3858 return true; 3859 } 3860 3861 // Here are all the checks a Store must pass before it can be moved into 3862 // an initialization. Returns zero if a check fails. 3863 // On success, returns the (constant) offset to which the store applies, 3864 // within the initialized memory. 3865 intptr_t InitializeNode::can_capture_store(StoreNode* st, PhaseGVN* phase, bool can_reshape) { 3866 const int FAIL = 0; 3867 if (st->req() != MemNode::ValueIn + 1) 3868 return FAIL; // an inscrutable StoreNode (card mark?) 3869 Node* ctl = st->in(MemNode::Control); 3870 if (!(ctl != NULL && ctl->is_Proj() && ctl->in(0) == this)) 3871 return FAIL; // must be unconditional after the initialization 3872 Node* mem = st->in(MemNode::Memory); 3873 if (!(mem->is_Proj() && mem->in(0) == this)) 3874 return FAIL; // must not be preceded by other stores 3875 Node* adr = st->in(MemNode::Address); 3876 intptr_t offset; 3877 AllocateNode* alloc = AllocateNode::Ideal_allocation(adr, phase, offset); 3878 if (alloc == NULL) 3879 return FAIL; // inscrutable address 3880 if (alloc != allocation()) 3881 return FAIL; // wrong allocation! (store needs to float up) 3882 int size_in_bytes = st->memory_size(); 3883 if ((size_in_bytes != 0) && (offset % size_in_bytes) != 0) { 3884 return FAIL; // mismatched access 3885 } 3886 Node* val = st->in(MemNode::ValueIn); 3887 3888 if (!detect_init_independence(val, phase)) 3889 return FAIL; // stored value must be 'simple enough' 3890 3891 // The Store can be captured only if nothing after the allocation 3892 // and before the Store is using the memory location that the store 3893 // overwrites. 3894 bool failed = false; 3895 // If is_complete_with_arraycopy() is true the shape of the graph is 3896 // well defined and is safe so no need for extra checks. 3897 if (!is_complete_with_arraycopy()) { 3898 // We are going to look at each use of the memory state following 3899 // the allocation to make sure nothing reads the memory that the 3900 // Store writes. 3901 const TypePtr* t_adr = phase->type(adr)->isa_ptr(); 3902 int alias_idx = phase->C->get_alias_index(t_adr); 3903 ResourceMark rm; 3904 Unique_Node_List mems; 3905 mems.push(mem); 3906 Node* unique_merge = NULL; 3907 for (uint next = 0; next < mems.size(); ++next) { 3908 Node *m = mems.at(next); 3909 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) { 3910 Node *n = m->fast_out(j); 3911 if (n->outcnt() == 0) { 3912 continue; 3913 } 3914 if (n == st) { 3915 continue; 3916 } else if (n->in(0) != NULL && n->in(0) != ctl) { 3917 // If the control of this use is different from the control 3918 // of the Store which is right after the InitializeNode then 3919 // this node cannot be between the InitializeNode and the 3920 // Store. 3921 continue; 3922 } else if (n->is_MergeMem()) { 3923 if (n->as_MergeMem()->memory_at(alias_idx) == m) { 3924 // We can hit a MergeMemNode (that will likely go away 3925 // later) that is a direct use of the memory state 3926 // following the InitializeNode on the same slice as the 3927 // store node that we'd like to capture. We need to check 3928 // the uses of the MergeMemNode. 3929 mems.push(n); 3930 } 3931 } else if (n->is_Mem()) { 3932 Node* other_adr = n->in(MemNode::Address); 3933 if (other_adr == adr) { 3934 failed = true; 3935 break; 3936 } else { 3937 const TypePtr* other_t_adr = phase->type(other_adr)->isa_ptr(); 3938 if (other_t_adr != NULL) { 3939 int other_alias_idx = phase->C->get_alias_index(other_t_adr); 3940 if (other_alias_idx == alias_idx) { 3941 // A load from the same memory slice as the store right 3942 // after the InitializeNode. We check the control of the 3943 // object/array that is loaded from. If it's the same as 3944 // the store control then we cannot capture the store. 3945 assert(!n->is_Store(), "2 stores to same slice on same control?"); 3946 Node* base = other_adr; 3947 if (base->is_Phi()) { 3948 // In rare case, base may be a PhiNode and it may read 3949 // the same memory slice between InitializeNode and store. 3950 failed = true; 3951 break; 3952 } 3953 assert(base->is_AddP(), "should be addp but is %s", base->Name()); 3954 base = base->in(AddPNode::Base); 3955 if (base != NULL) { 3956 base = base->uncast(); 3957 if (base->is_Proj() && base->in(0) == alloc) { 3958 failed = true; 3959 break; 3960 } 3961 } 3962 } 3963 } 3964 } 3965 } else { 3966 failed = true; 3967 break; 3968 } 3969 } 3970 } 3971 } 3972 if (failed) { 3973 if (!can_reshape) { 3974 // We decided we couldn't capture the store during parsing. We 3975 // should try again during the next IGVN once the graph is 3976 // cleaner. 3977 phase->C->record_for_igvn(st); 3978 } 3979 return FAIL; 3980 } 3981 3982 return offset; // success 3983 } 3984 3985 // Find the captured store in(i) which corresponds to the range 3986 // [start..start+size) in the initialized object. 3987 // If there is one, return its index i. If there isn't, return the 3988 // negative of the index where it should be inserted. 3989 // Return 0 if the queried range overlaps an initialization boundary 3990 // or if dead code is encountered. 3991 // If size_in_bytes is zero, do not bother with overlap checks. 3992 int InitializeNode::captured_store_insertion_point(intptr_t start, 3993 int size_in_bytes, 3994 PhaseTransform* phase) { 3995 const int FAIL = 0, MAX_STORE = MAX2(BytesPerLong, (int)MaxVectorSize); 3996 3997 if (is_complete()) 3998 return FAIL; // arraycopy got here first; punt 3999 4000 assert(allocation() != NULL, "must be present"); 4001 4002 // no negatives, no header fields: 4003 if (start < (intptr_t) allocation()->minimum_header_size()) return FAIL; 4004 4005 // after a certain size, we bail out on tracking all the stores: 4006 intptr_t ti_limit = (TrackedInitializationLimit * HeapWordSize); 4007 if (start >= ti_limit) return FAIL; 4008 4009 for (uint i = InitializeNode::RawStores, limit = req(); ; ) { 4010 if (i >= limit) return -(int)i; // not found; here is where to put it 4011 4012 Node* st = in(i); 4013 intptr_t st_off = get_store_offset(st, phase); 4014 if (st_off < 0) { 4015 if (st != zero_memory()) { 4016 return FAIL; // bail out if there is dead garbage 4017 } 4018 } else if (st_off > start) { 4019 // ...we are done, since stores are ordered 4020 if (st_off < start + size_in_bytes) { 4021 return FAIL; // the next store overlaps 4022 } 4023 return -(int)i; // not found; here is where to put it 4024 } else if (st_off < start) { 4025 assert(st->as_Store()->memory_size() <= MAX_STORE, ""); 4026 if (size_in_bytes != 0 && 4027 start < st_off + MAX_STORE && 4028 start < st_off + st->as_Store()->memory_size()) { 4029 return FAIL; // the previous store overlaps 4030 } 4031 } else { 4032 if (size_in_bytes != 0 && 4033 st->as_Store()->memory_size() != size_in_bytes) { 4034 return FAIL; // mismatched store size 4035 } 4036 return i; 4037 } 4038 4039 ++i; 4040 } 4041 } 4042 4043 // Look for a captured store which initializes at the offset 'start' 4044 // with the given size. If there is no such store, and no other 4045 // initialization interferes, then return zero_memory (the memory 4046 // projection of the AllocateNode). 4047 Node* InitializeNode::find_captured_store(intptr_t start, int size_in_bytes, 4048 PhaseTransform* phase) { 4049 assert(stores_are_sane(phase), ""); 4050 int i = captured_store_insertion_point(start, size_in_bytes, phase); 4051 if (i == 0) { 4052 return NULL; // something is dead 4053 } else if (i < 0) { 4054 return zero_memory(); // just primordial zero bits here 4055 } else { 4056 Node* st = in(i); // here is the store at this position 4057 assert(get_store_offset(st->as_Store(), phase) == start, "sanity"); 4058 return st; 4059 } 4060 } 4061 4062 // Create, as a raw pointer, an address within my new object at 'offset'. 4063 Node* InitializeNode::make_raw_address(intptr_t offset, 4064 PhaseTransform* phase) { 4065 Node* addr = in(RawAddress); 4066 if (offset != 0) { 4067 Compile* C = phase->C; 4068 addr = phase->transform( new AddPNode(C->top(), addr, 4069 phase->MakeConX(offset)) ); 4070 } 4071 return addr; 4072 } 4073 4074 // Clone the given store, converting it into a raw store 4075 // initializing a field or element of my new object. 4076 // Caller is responsible for retiring the original store, 4077 // with subsume_node or the like. 4078 // 4079 // From the example above InitializeNode::InitializeNode, 4080 // here are the old stores to be captured: 4081 // store1 = (StoreC init.Control init.Memory (+ oop 12) 1) 4082 // store2 = (StoreC init.Control store1 (+ oop 14) 2) 4083 // 4084 // Here is the changed code; note the extra edges on init: 4085 // alloc = (Allocate ...) 4086 // rawoop = alloc.RawAddress 4087 // rawstore1 = (StoreC alloc.Control alloc.Memory (+ rawoop 12) 1) 4088 // rawstore2 = (StoreC alloc.Control alloc.Memory (+ rawoop 14) 2) 4089 // init = (Initialize alloc.Control alloc.Memory rawoop 4090 // rawstore1 rawstore2) 4091 // 4092 Node* InitializeNode::capture_store(StoreNode* st, intptr_t start, 4093 PhaseGVN* phase, bool can_reshape) { 4094 assert(stores_are_sane(phase), ""); 4095 4096 if (start < 0) return NULL; 4097 assert(can_capture_store(st, phase, can_reshape) == start, "sanity"); 4098 4099 Compile* C = phase->C; 4100 int size_in_bytes = st->memory_size(); 4101 int i = captured_store_insertion_point(start, size_in_bytes, phase); 4102 if (i == 0) return NULL; // bail out 4103 Node* prev_mem = NULL; // raw memory for the captured store 4104 if (i > 0) { 4105 prev_mem = in(i); // there is a pre-existing store under this one 4106 set_req(i, C->top()); // temporarily disconnect it 4107 // See StoreNode::Ideal 'st->outcnt() == 1' for the reason to disconnect. 4108 } else { 4109 i = -i; // no pre-existing store 4110 prev_mem = zero_memory(); // a slice of the newly allocated object 4111 if (i > InitializeNode::RawStores && in(i-1) == prev_mem) 4112 set_req(--i, C->top()); // reuse this edge; it has been folded away 4113 else 4114 ins_req(i, C->top()); // build a new edge 4115 } 4116 Node* new_st = st->clone(); 4117 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2(); 4118 new_st->set_req(MemNode::Control, in(Control)); 4119 new_st->set_req(MemNode::Memory, prev_mem); 4120 new_st->set_req(MemNode::Address, make_raw_address(start, phase)); 4121 bs->eliminate_gc_barrier_data(new_st); 4122 new_st = phase->transform(new_st); 4123 4124 // At this point, new_st might have swallowed a pre-existing store 4125 // at the same offset, or perhaps new_st might have disappeared, 4126 // if it redundantly stored the same value (or zero to fresh memory). 4127 4128 // In any case, wire it in: 4129 PhaseIterGVN* igvn = phase->is_IterGVN(); 4130 if (igvn) { 4131 igvn->rehash_node_delayed(this); 4132 } 4133 set_req(i, new_st); 4134 4135 // The caller may now kill the old guy. 4136 DEBUG_ONLY(Node* check_st = find_captured_store(start, size_in_bytes, phase)); 4137 assert(check_st == new_st || check_st == NULL, "must be findable"); 4138 assert(!is_complete(), ""); 4139 return new_st; 4140 } 4141 4142 static bool store_constant(jlong* tiles, int num_tiles, 4143 intptr_t st_off, int st_size, 4144 jlong con) { 4145 if ((st_off & (st_size-1)) != 0) 4146 return false; // strange store offset (assume size==2**N) 4147 address addr = (address)tiles + st_off; 4148 assert(st_off >= 0 && addr+st_size <= (address)&tiles[num_tiles], "oob"); 4149 switch (st_size) { 4150 case sizeof(jbyte): *(jbyte*) addr = (jbyte) con; break; 4151 case sizeof(jchar): *(jchar*) addr = (jchar) con; break; 4152 case sizeof(jint): *(jint*) addr = (jint) con; break; 4153 case sizeof(jlong): *(jlong*) addr = (jlong) con; break; 4154 default: return false; // strange store size (detect size!=2**N here) 4155 } 4156 return true; // return success to caller 4157 } 4158 4159 // Coalesce subword constants into int constants and possibly 4160 // into long constants. The goal, if the CPU permits, 4161 // is to initialize the object with a small number of 64-bit tiles. 4162 // Also, convert floating-point constants to bit patterns. 4163 // Non-constants are not relevant to this pass. 4164 // 4165 // In terms of the running example on InitializeNode::InitializeNode 4166 // and InitializeNode::capture_store, here is the transformation 4167 // of rawstore1 and rawstore2 into rawstore12: 4168 // alloc = (Allocate ...) 4169 // rawoop = alloc.RawAddress 4170 // tile12 = 0x00010002 4171 // rawstore12 = (StoreI alloc.Control alloc.Memory (+ rawoop 12) tile12) 4172 // init = (Initialize alloc.Control alloc.Memory rawoop rawstore12) 4173 // 4174 void 4175 InitializeNode::coalesce_subword_stores(intptr_t header_size, 4176 Node* size_in_bytes, 4177 PhaseGVN* phase) { 4178 Compile* C = phase->C; 4179 4180 assert(stores_are_sane(phase), ""); 4181 // Note: After this pass, they are not completely sane, 4182 // since there may be some overlaps. 4183 4184 int old_subword = 0, old_long = 0, new_int = 0, new_long = 0; 4185 4186 intptr_t ti_limit = (TrackedInitializationLimit * HeapWordSize); 4187 intptr_t size_limit = phase->find_intptr_t_con(size_in_bytes, ti_limit); 4188 size_limit = MIN2(size_limit, ti_limit); 4189 size_limit = align_up(size_limit, BytesPerLong); 4190 int num_tiles = size_limit / BytesPerLong; 4191 4192 // allocate space for the tile map: 4193 const int small_len = DEBUG_ONLY(true ? 3 :) 30; // keep stack frames small 4194 jlong tiles_buf[small_len]; 4195 Node* nodes_buf[small_len]; 4196 jlong inits_buf[small_len]; 4197 jlong* tiles = ((num_tiles <= small_len) ? &tiles_buf[0] 4198 : NEW_RESOURCE_ARRAY(jlong, num_tiles)); 4199 Node** nodes = ((num_tiles <= small_len) ? &nodes_buf[0] 4200 : NEW_RESOURCE_ARRAY(Node*, num_tiles)); 4201 jlong* inits = ((num_tiles <= small_len) ? &inits_buf[0] 4202 : NEW_RESOURCE_ARRAY(jlong, num_tiles)); 4203 // tiles: exact bitwise model of all primitive constants 4204 // nodes: last constant-storing node subsumed into the tiles model 4205 // inits: which bytes (in each tile) are touched by any initializations 4206 4207 //// Pass A: Fill in the tile model with any relevant stores. 4208 4209 Copy::zero_to_bytes(tiles, sizeof(tiles[0]) * num_tiles); 4210 Copy::zero_to_bytes(nodes, sizeof(nodes[0]) * num_tiles); 4211 Copy::zero_to_bytes(inits, sizeof(inits[0]) * num_tiles); 4212 Node* zmem = zero_memory(); // initially zero memory state 4213 for (uint i = InitializeNode::RawStores, limit = req(); i < limit; i++) { 4214 Node* st = in(i); 4215 intptr_t st_off = get_store_offset(st, phase); 4216 4217 // Figure out the store's offset and constant value: 4218 if (st_off < header_size) continue; //skip (ignore header) 4219 if (st->in(MemNode::Memory) != zmem) continue; //skip (odd store chain) 4220 int st_size = st->as_Store()->memory_size(); 4221 if (st_off + st_size > size_limit) break; 4222 4223 // Record which bytes are touched, whether by constant or not. 4224 if (!store_constant(inits, num_tiles, st_off, st_size, (jlong) -1)) 4225 continue; // skip (strange store size) 4226 4227 const Type* val = phase->type(st->in(MemNode::ValueIn)); 4228 if (!val->singleton()) continue; //skip (non-con store) 4229 BasicType type = val->basic_type(); 4230 4231 jlong con = 0; 4232 switch (type) { 4233 case T_INT: con = val->is_int()->get_con(); break; 4234 case T_LONG: con = val->is_long()->get_con(); break; 4235 case T_FLOAT: con = jint_cast(val->getf()); break; 4236 case T_DOUBLE: con = jlong_cast(val->getd()); break; 4237 default: continue; //skip (odd store type) 4238 } 4239 4240 if (type == T_LONG && Matcher::isSimpleConstant64(con) && 4241 st->Opcode() == Op_StoreL) { 4242 continue; // This StoreL is already optimal. 4243 } 4244 4245 // Store down the constant. 4246 store_constant(tiles, num_tiles, st_off, st_size, con); 4247 4248 intptr_t j = st_off >> LogBytesPerLong; 4249 4250 if (type == T_INT && st_size == BytesPerInt 4251 && (st_off & BytesPerInt) == BytesPerInt) { 4252 jlong lcon = tiles[j]; 4253 if (!Matcher::isSimpleConstant64(lcon) && 4254 st->Opcode() == Op_StoreI) { 4255 // This StoreI is already optimal by itself. 4256 jint* intcon = (jint*) &tiles[j]; 4257 intcon[1] = 0; // undo the store_constant() 4258 4259 // If the previous store is also optimal by itself, back up and 4260 // undo the action of the previous loop iteration... if we can. 4261 // But if we can't, just let the previous half take care of itself. 4262 st = nodes[j]; 4263 st_off -= BytesPerInt; 4264 con = intcon[0]; 4265 if (con != 0 && st != NULL && st->Opcode() == Op_StoreI) { 4266 assert(st_off >= header_size, "still ignoring header"); 4267 assert(get_store_offset(st, phase) == st_off, "must be"); 4268 assert(in(i-1) == zmem, "must be"); 4269 DEBUG_ONLY(const Type* tcon = phase->type(st->in(MemNode::ValueIn))); 4270 assert(con == tcon->is_int()->get_con(), "must be"); 4271 // Undo the effects of the previous loop trip, which swallowed st: 4272 intcon[0] = 0; // undo store_constant() 4273 set_req(i-1, st); // undo set_req(i, zmem) 4274 nodes[j] = NULL; // undo nodes[j] = st 4275 --old_subword; // undo ++old_subword 4276 } 4277 continue; // This StoreI is already optimal. 4278 } 4279 } 4280 4281 // This store is not needed. 4282 set_req(i, zmem); 4283 nodes[j] = st; // record for the moment 4284 if (st_size < BytesPerLong) // something has changed 4285 ++old_subword; // includes int/float, but who's counting... 4286 else ++old_long; 4287 } 4288 4289 if ((old_subword + old_long) == 0) 4290 return; // nothing more to do 4291 4292 //// Pass B: Convert any non-zero tiles into optimal constant stores. 4293 // Be sure to insert them before overlapping non-constant stores. 4294 // (E.g., byte[] x = { 1,2,y,4 } => x[int 0] = 0x01020004, x[2]=y.) 4295 for (int j = 0; j < num_tiles; j++) { 4296 jlong con = tiles[j]; 4297 jlong init = inits[j]; 4298 if (con == 0) continue; 4299 jint con0, con1; // split the constant, address-wise 4300 jint init0, init1; // split the init map, address-wise 4301 { union { jlong con; jint intcon[2]; } u; 4302 u.con = con; 4303 con0 = u.intcon[0]; 4304 con1 = u.intcon[1]; 4305 u.con = init; 4306 init0 = u.intcon[0]; 4307 init1 = u.intcon[1]; 4308 } 4309 4310 Node* old = nodes[j]; 4311 assert(old != NULL, "need the prior store"); 4312 intptr_t offset = (j * BytesPerLong); 4313 4314 bool split = !Matcher::isSimpleConstant64(con); 4315 4316 if (offset < header_size) { 4317 assert(offset + BytesPerInt >= header_size, "second int counts"); 4318 assert(*(jint*)&tiles[j] == 0, "junk in header"); 4319 split = true; // only the second word counts 4320 // Example: int a[] = { 42 ... } 4321 } else if (con0 == 0 && init0 == -1) { 4322 split = true; // first word is covered by full inits 4323 // Example: int a[] = { ... foo(), 42 ... } 4324 } else if (con1 == 0 && init1 == -1) { 4325 split = true; // second word is covered by full inits 4326 // Example: int a[] = { ... 42, foo() ... } 4327 } 4328 4329 // Here's a case where init0 is neither 0 nor -1: 4330 // byte a[] = { ... 0,0,foo(),0, 0,0,0,42 ... } 4331 // Assuming big-endian memory, init0, init1 are 0x0000FF00, 0x000000FF. 4332 // In this case the tile is not split; it is (jlong)42. 4333 // The big tile is stored down, and then the foo() value is inserted. 4334 // (If there were foo(),foo() instead of foo(),0, init0 would be -1.) 4335 4336 Node* ctl = old->in(MemNode::Control); 4337 Node* adr = make_raw_address(offset, phase); 4338 const TypePtr* atp = TypeRawPtr::BOTTOM; 4339 4340 // One or two coalesced stores to plop down. 4341 Node* st[2]; 4342 intptr_t off[2]; 4343 int nst = 0; 4344 if (!split) { 4345 ++new_long; 4346 off[nst] = offset; 4347 st[nst++] = StoreNode::make(*phase, ctl, zmem, adr, atp, 4348 phase->longcon(con), T_LONG, MemNode::unordered); 4349 } else { 4350 // Omit either if it is a zero. 4351 if (con0 != 0) { 4352 ++new_int; 4353 off[nst] = offset; 4354 st[nst++] = StoreNode::make(*phase, ctl, zmem, adr, atp, 4355 phase->intcon(con0), T_INT, MemNode::unordered); 4356 } 4357 if (con1 != 0) { 4358 ++new_int; 4359 offset += BytesPerInt; 4360 adr = make_raw_address(offset, phase); 4361 off[nst] = offset; 4362 st[nst++] = StoreNode::make(*phase, ctl, zmem, adr, atp, 4363 phase->intcon(con1), T_INT, MemNode::unordered); 4364 } 4365 } 4366 4367 // Insert second store first, then the first before the second. 4368 // Insert each one just before any overlapping non-constant stores. 4369 while (nst > 0) { 4370 Node* st1 = st[--nst]; 4371 C->copy_node_notes_to(st1, old); 4372 st1 = phase->transform(st1); 4373 offset = off[nst]; 4374 assert(offset >= header_size, "do not smash header"); 4375 int ins_idx = captured_store_insertion_point(offset, /*size:*/0, phase); 4376 guarantee(ins_idx != 0, "must re-insert constant store"); 4377 if (ins_idx < 0) ins_idx = -ins_idx; // never overlap 4378 if (ins_idx > InitializeNode::RawStores && in(ins_idx-1) == zmem) 4379 set_req(--ins_idx, st1); 4380 else 4381 ins_req(ins_idx, st1); 4382 } 4383 } 4384 4385 if (PrintCompilation && WizardMode) 4386 tty->print_cr("Changed %d/%d subword/long constants into %d/%d int/long", 4387 old_subword, old_long, new_int, new_long); 4388 if (C->log() != NULL) 4389 C->log()->elem("comment that='%d/%d subword/long to %d/%d int/long'", 4390 old_subword, old_long, new_int, new_long); 4391 4392 // Clean up any remaining occurrences of zmem: 4393 remove_extra_zeroes(); 4394 } 4395 4396 // Explore forward from in(start) to find the first fully initialized 4397 // word, and return its offset. Skip groups of subword stores which 4398 // together initialize full words. If in(start) is itself part of a 4399 // fully initialized word, return the offset of in(start). If there 4400 // are no following full-word stores, or if something is fishy, return 4401 // a negative value. 4402 intptr_t InitializeNode::find_next_fullword_store(uint start, PhaseGVN* phase) { 4403 int int_map = 0; 4404 intptr_t int_map_off = 0; 4405 const int FULL_MAP = right_n_bits(BytesPerInt); // the int_map we hope for 4406 4407 for (uint i = start, limit = req(); i < limit; i++) { 4408 Node* st = in(i); 4409 4410 intptr_t st_off = get_store_offset(st, phase); 4411 if (st_off < 0) break; // return conservative answer 4412 4413 int st_size = st->as_Store()->memory_size(); 4414 if (st_size >= BytesPerInt && (st_off % BytesPerInt) == 0) { 4415 return st_off; // we found a complete word init 4416 } 4417 4418 // update the map: 4419 4420 intptr_t this_int_off = align_down(st_off, BytesPerInt); 4421 if (this_int_off != int_map_off) { 4422 // reset the map: 4423 int_map = 0; 4424 int_map_off = this_int_off; 4425 } 4426 4427 int subword_off = st_off - this_int_off; 4428 int_map |= right_n_bits(st_size) << subword_off; 4429 if ((int_map & FULL_MAP) == FULL_MAP) { 4430 return this_int_off; // we found a complete word init 4431 } 4432 4433 // Did this store hit or cross the word boundary? 4434 intptr_t next_int_off = align_down(st_off + st_size, BytesPerInt); 4435 if (next_int_off == this_int_off + BytesPerInt) { 4436 // We passed the current int, without fully initializing it. 4437 int_map_off = next_int_off; 4438 int_map >>= BytesPerInt; 4439 } else if (next_int_off > this_int_off + BytesPerInt) { 4440 // We passed the current and next int. 4441 return this_int_off + BytesPerInt; 4442 } 4443 } 4444 4445 return -1; 4446 } 4447 4448 4449 // Called when the associated AllocateNode is expanded into CFG. 4450 // At this point, we may perform additional optimizations. 4451 // Linearize the stores by ascending offset, to make memory 4452 // activity as coherent as possible. 4453 Node* InitializeNode::complete_stores(Node* rawctl, Node* rawmem, Node* rawptr, 4454 intptr_t header_size, 4455 Node* size_in_bytes, 4456 PhaseIterGVN* phase) { 4457 assert(!is_complete(), "not already complete"); 4458 assert(stores_are_sane(phase), ""); 4459 assert(allocation() != NULL, "must be present"); 4460 4461 remove_extra_zeroes(); 4462 4463 if (ReduceFieldZeroing || ReduceBulkZeroing) 4464 // reduce instruction count for common initialization patterns 4465 coalesce_subword_stores(header_size, size_in_bytes, phase); 4466 4467 Node* zmem = zero_memory(); // initially zero memory state 4468 Node* inits = zmem; // accumulating a linearized chain of inits 4469 #ifdef ASSERT 4470 intptr_t first_offset = allocation()->minimum_header_size(); 4471 intptr_t last_init_off = first_offset; // previous init offset 4472 intptr_t last_init_end = first_offset; // previous init offset+size 4473 intptr_t last_tile_end = first_offset; // previous tile offset+size 4474 #endif 4475 intptr_t zeroes_done = header_size; 4476 4477 bool do_zeroing = true; // we might give up if inits are very sparse 4478 int big_init_gaps = 0; // how many large gaps have we seen? 4479 4480 if (UseTLAB && ZeroTLAB) do_zeroing = false; 4481 if (!ReduceFieldZeroing && !ReduceBulkZeroing) do_zeroing = false; 4482 4483 for (uint i = InitializeNode::RawStores, limit = req(); i < limit; i++) { 4484 Node* st = in(i); 4485 intptr_t st_off = get_store_offset(st, phase); 4486 if (st_off < 0) 4487 break; // unknown junk in the inits 4488 if (st->in(MemNode::Memory) != zmem) 4489 break; // complicated store chains somehow in list 4490 4491 int st_size = st->as_Store()->memory_size(); 4492 intptr_t next_init_off = st_off + st_size; 4493 4494 if (do_zeroing && zeroes_done < next_init_off) { 4495 // See if this store needs a zero before it or under it. 4496 intptr_t zeroes_needed = st_off; 4497 4498 if (st_size < BytesPerInt) { 4499 // Look for subword stores which only partially initialize words. 4500 // If we find some, we must lay down some word-level zeroes first, 4501 // underneath the subword stores. 4502 // 4503 // Examples: 4504 // byte[] a = { p,q,r,s } => a[0]=p,a[1]=q,a[2]=r,a[3]=s 4505 // byte[] a = { x,y,0,0 } => a[0..3] = 0, a[0]=x,a[1]=y 4506 // byte[] a = { 0,0,z,0 } => a[0..3] = 0, a[2]=z 4507 // 4508 // Note: coalesce_subword_stores may have already done this, 4509 // if it was prompted by constant non-zero subword initializers. 4510 // But this case can still arise with non-constant stores. 4511 4512 intptr_t next_full_store = find_next_fullword_store(i, phase); 4513 4514 // In the examples above: 4515 // in(i) p q r s x y z 4516 // st_off 12 13 14 15 12 13 14 4517 // st_size 1 1 1 1 1 1 1 4518 // next_full_s. 12 16 16 16 16 16 16 4519 // z's_done 12 16 16 16 12 16 12 4520 // z's_needed 12 16 16 16 16 16 16 4521 // zsize 0 0 0 0 4 0 4 4522 if (next_full_store < 0) { 4523 // Conservative tack: Zero to end of current word. 4524 zeroes_needed = align_up(zeroes_needed, BytesPerInt); 4525 } else { 4526 // Zero to beginning of next fully initialized word. 4527 // Or, don't zero at all, if we are already in that word. 4528 assert(next_full_store >= zeroes_needed, "must go forward"); 4529 assert((next_full_store & (BytesPerInt-1)) == 0, "even boundary"); 4530 zeroes_needed = next_full_store; 4531 } 4532 } 4533 4534 if (zeroes_needed > zeroes_done) { 4535 intptr_t zsize = zeroes_needed - zeroes_done; 4536 // Do some incremental zeroing on rawmem, in parallel with inits. 4537 zeroes_done = align_down(zeroes_done, BytesPerInt); 4538 rawmem = ClearArrayNode::clear_memory(rawctl, rawmem, rawptr, 4539 allocation()->in(AllocateNode::DefaultValue), 4540 allocation()->in(AllocateNode::RawDefaultValue), 4541 zeroes_done, zeroes_needed, 4542 phase); 4543 zeroes_done = zeroes_needed; 4544 if (zsize > InitArrayShortSize && ++big_init_gaps > 2) 4545 do_zeroing = false; // leave the hole, next time 4546 } 4547 } 4548 4549 // Collect the store and move on: 4550 phase->replace_input_of(st, MemNode::Memory, inits); 4551 inits = st; // put it on the linearized chain 4552 set_req(i, zmem); // unhook from previous position 4553 4554 if (zeroes_done == st_off) 4555 zeroes_done = next_init_off; 4556 4557 assert(!do_zeroing || zeroes_done >= next_init_off, "don't miss any"); 4558 4559 #ifdef ASSERT 4560 // Various order invariants. Weaker than stores_are_sane because 4561 // a large constant tile can be filled in by smaller non-constant stores. 4562 assert(st_off >= last_init_off, "inits do not reverse"); 4563 last_init_off = st_off; 4564 const Type* val = NULL; 4565 if (st_size >= BytesPerInt && 4566 (val = phase->type(st->in(MemNode::ValueIn)))->singleton() && 4567 (int)val->basic_type() < (int)T_OBJECT) { 4568 assert(st_off >= last_tile_end, "tiles do not overlap"); 4569 assert(st_off >= last_init_end, "tiles do not overwrite inits"); 4570 last_tile_end = MAX2(last_tile_end, next_init_off); 4571 } else { 4572 intptr_t st_tile_end = align_up(next_init_off, BytesPerLong); 4573 assert(st_tile_end >= last_tile_end, "inits stay with tiles"); 4574 assert(st_off >= last_init_end, "inits do not overlap"); 4575 last_init_end = next_init_off; // it's a non-tile 4576 } 4577 #endif //ASSERT 4578 } 4579 4580 remove_extra_zeroes(); // clear out all the zmems left over 4581 add_req(inits); 4582 4583 if (!(UseTLAB && ZeroTLAB)) { 4584 // If anything remains to be zeroed, zero it all now. 4585 zeroes_done = align_down(zeroes_done, BytesPerInt); 4586 // if it is the last unused 4 bytes of an instance, forget about it 4587 intptr_t size_limit = phase->find_intptr_t_con(size_in_bytes, max_jint); 4588 if (zeroes_done + BytesPerLong >= size_limit) { 4589 AllocateNode* alloc = allocation(); 4590 assert(alloc != NULL, "must be present"); 4591 if (alloc != NULL && alloc->Opcode() == Op_Allocate) { 4592 Node* klass_node = alloc->in(AllocateNode::KlassNode); 4593 ciKlass* k = phase->type(klass_node)->is_instklassptr()->instance_klass(); 4594 if (zeroes_done == k->layout_helper()) 4595 zeroes_done = size_limit; 4596 } 4597 } 4598 if (zeroes_done < size_limit) { 4599 rawmem = ClearArrayNode::clear_memory(rawctl, rawmem, rawptr, 4600 allocation()->in(AllocateNode::DefaultValue), 4601 allocation()->in(AllocateNode::RawDefaultValue), 4602 zeroes_done, size_in_bytes, phase); 4603 } 4604 } 4605 4606 set_complete(phase); 4607 return rawmem; 4608 } 4609 4610 4611 #ifdef ASSERT 4612 bool InitializeNode::stores_are_sane(PhaseTransform* phase) { 4613 if (is_complete()) 4614 return true; // stores could be anything at this point 4615 assert(allocation() != NULL, "must be present"); 4616 intptr_t last_off = allocation()->minimum_header_size(); 4617 for (uint i = InitializeNode::RawStores; i < req(); i++) { 4618 Node* st = in(i); 4619 intptr_t st_off = get_store_offset(st, phase); 4620 if (st_off < 0) continue; // ignore dead garbage 4621 if (last_off > st_off) { 4622 tty->print_cr("*** bad store offset at %d: " INTX_FORMAT " > " INTX_FORMAT, i, last_off, st_off); 4623 this->dump(2); 4624 assert(false, "ascending store offsets"); 4625 return false; 4626 } 4627 last_off = st_off + st->as_Store()->memory_size(); 4628 } 4629 return true; 4630 } 4631 #endif //ASSERT 4632 4633 4634 4635 4636 //============================MergeMemNode===================================== 4637 // 4638 // SEMANTICS OF MEMORY MERGES: A MergeMem is a memory state assembled from several 4639 // contributing store or call operations. Each contributor provides the memory 4640 // state for a particular "alias type" (see Compile::alias_type). For example, 4641 // if a MergeMem has an input X for alias category #6, then any memory reference 4642 // to alias category #6 may use X as its memory state input, as an exact equivalent 4643 // to using the MergeMem as a whole. 4644 // Load<6>( MergeMem(<6>: X, ...), p ) <==> Load<6>(X,p) 4645 // 4646 // (Here, the <N> notation gives the index of the relevant adr_type.) 4647 // 4648 // In one special case (and more cases in the future), alias categories overlap. 4649 // The special alias category "Bot" (Compile::AliasIdxBot) includes all memory 4650 // states. Therefore, if a MergeMem has only one contributing input W for Bot, 4651 // it is exactly equivalent to that state W: 4652 // MergeMem(<Bot>: W) <==> W 4653 // 4654 // Usually, the merge has more than one input. In that case, where inputs 4655 // overlap (i.e., one is Bot), the narrower alias type determines the memory 4656 // state for that type, and the wider alias type (Bot) fills in everywhere else: 4657 // Load<5>( MergeMem(<Bot>: W, <6>: X), p ) <==> Load<5>(W,p) 4658 // Load<6>( MergeMem(<Bot>: W, <6>: X), p ) <==> Load<6>(X,p) 4659 // 4660 // A merge can take a "wide" memory state as one of its narrow inputs. 4661 // This simply means that the merge observes out only the relevant parts of 4662 // the wide input. That is, wide memory states arriving at narrow merge inputs 4663 // are implicitly "filtered" or "sliced" as necessary. (This is rare.) 4664 // 4665 // These rules imply that MergeMem nodes may cascade (via their <Bot> links), 4666 // and that memory slices "leak through": 4667 // MergeMem(<Bot>: MergeMem(<Bot>: W, <7>: Y)) <==> MergeMem(<Bot>: W, <7>: Y) 4668 // 4669 // But, in such a cascade, repeated memory slices can "block the leak": 4670 // MergeMem(<Bot>: MergeMem(<Bot>: W, <7>: Y), <7>: Y') <==> MergeMem(<Bot>: W, <7>: Y') 4671 // 4672 // In the last example, Y is not part of the combined memory state of the 4673 // outermost MergeMem. The system must, of course, prevent unschedulable 4674 // memory states from arising, so you can be sure that the state Y is somehow 4675 // a precursor to state Y'. 4676 // 4677 // 4678 // REPRESENTATION OF MEMORY MERGES: The indexes used to address the Node::in array 4679 // of each MergeMemNode array are exactly the numerical alias indexes, including 4680 // but not limited to AliasIdxTop, AliasIdxBot, and AliasIdxRaw. The functions 4681 // Compile::alias_type (and kin) produce and manage these indexes. 4682 // 4683 // By convention, the value of in(AliasIdxTop) (i.e., in(1)) is always the top node. 4684 // (Note that this provides quick access to the top node inside MergeMem methods, 4685 // without the need to reach out via TLS to Compile::current.) 4686 // 4687 // As a consequence of what was just described, a MergeMem that represents a full 4688 // memory state has an edge in(AliasIdxBot) which is a "wide" memory state, 4689 // containing all alias categories. 4690 // 4691 // MergeMem nodes never (?) have control inputs, so in(0) is NULL. 4692 // 4693 // All other edges in(N) (including in(AliasIdxRaw), which is in(3)) are either 4694 // a memory state for the alias type <N>, or else the top node, meaning that 4695 // there is no particular input for that alias type. Note that the length of 4696 // a MergeMem is variable, and may be extended at any time to accommodate new 4697 // memory states at larger alias indexes. When merges grow, they are of course 4698 // filled with "top" in the unused in() positions. 4699 // 4700 // This use of top is named "empty_memory()", or "empty_mem" (no-memory) as a variable. 4701 // (Top was chosen because it works smoothly with passes like GCM.) 4702 // 4703 // For convenience, we hardwire the alias index for TypeRawPtr::BOTTOM. (It is 4704 // the type of random VM bits like TLS references.) Since it is always the 4705 // first non-Bot memory slice, some low-level loops use it to initialize an 4706 // index variable: for (i = AliasIdxRaw; i < req(); i++). 4707 // 4708 // 4709 // ACCESSORS: There is a special accessor MergeMemNode::base_memory which returns 4710 // the distinguished "wide" state. The accessor MergeMemNode::memory_at(N) returns 4711 // the memory state for alias type <N>, or (if there is no particular slice at <N>, 4712 // it returns the base memory. To prevent bugs, memory_at does not accept <Top> 4713 // or <Bot> indexes. The iterator MergeMemStream provides robust iteration over 4714 // MergeMem nodes or pairs of such nodes, ensuring that the non-top edges are visited. 4715 // 4716 // %%%% We may get rid of base_memory as a separate accessor at some point; it isn't 4717 // really that different from the other memory inputs. An abbreviation called 4718 // "bot_memory()" for "memory_at(AliasIdxBot)" would keep code tidy. 4719 // 4720 // 4721 // PARTIAL MEMORY STATES: During optimization, MergeMem nodes may arise that represent 4722 // partial memory states. When a Phi splits through a MergeMem, the copy of the Phi 4723 // that "emerges though" the base memory will be marked as excluding the alias types 4724 // of the other (narrow-memory) copies which "emerged through" the narrow edges: 4725 // 4726 // Phi<Bot>(U, MergeMem(<Bot>: W, <8>: Y)) 4727 // ==Ideal=> MergeMem(<Bot>: Phi<Bot-8>(U, W), Phi<8>(U, Y)) 4728 // 4729 // This strange "subtraction" effect is necessary to ensure IGVN convergence. 4730 // (It is currently unimplemented.) As you can see, the resulting merge is 4731 // actually a disjoint union of memory states, rather than an overlay. 4732 // 4733 4734 //------------------------------MergeMemNode----------------------------------- 4735 Node* MergeMemNode::make_empty_memory() { 4736 Node* empty_memory = (Node*) Compile::current()->top(); 4737 assert(empty_memory->is_top(), "correct sentinel identity"); 4738 return empty_memory; 4739 } 4740 4741 MergeMemNode::MergeMemNode(Node *new_base) : Node(1+Compile::AliasIdxRaw) { 4742 init_class_id(Class_MergeMem); 4743 // all inputs are nullified in Node::Node(int) 4744 // set_input(0, NULL); // no control input 4745 4746 // Initialize the edges uniformly to top, for starters. 4747 Node* empty_mem = make_empty_memory(); 4748 for (uint i = Compile::AliasIdxTop; i < req(); i++) { 4749 init_req(i,empty_mem); 4750 } 4751 assert(empty_memory() == empty_mem, ""); 4752 4753 if( new_base != NULL && new_base->is_MergeMem() ) { 4754 MergeMemNode* mdef = new_base->as_MergeMem(); 4755 assert(mdef->empty_memory() == empty_mem, "consistent sentinels"); 4756 for (MergeMemStream mms(this, mdef); mms.next_non_empty2(); ) { 4757 mms.set_memory(mms.memory2()); 4758 } 4759 assert(base_memory() == mdef->base_memory(), ""); 4760 } else { 4761 set_base_memory(new_base); 4762 } 4763 } 4764 4765 // Make a new, untransformed MergeMem with the same base as 'mem'. 4766 // If mem is itself a MergeMem, populate the result with the same edges. 4767 MergeMemNode* MergeMemNode::make(Node* mem) { 4768 return new MergeMemNode(mem); 4769 } 4770 4771 //------------------------------cmp-------------------------------------------- 4772 uint MergeMemNode::hash() const { return NO_HASH; } 4773 bool MergeMemNode::cmp( const Node &n ) const { 4774 return (&n == this); // Always fail except on self 4775 } 4776 4777 //------------------------------Identity--------------------------------------- 4778 Node* MergeMemNode::Identity(PhaseGVN* phase) { 4779 // Identity if this merge point does not record any interesting memory 4780 // disambiguations. 4781 Node* base_mem = base_memory(); 4782 Node* empty_mem = empty_memory(); 4783 if (base_mem != empty_mem) { // Memory path is not dead? 4784 for (uint i = Compile::AliasIdxRaw; i < req(); i++) { 4785 Node* mem = in(i); 4786 if (mem != empty_mem && mem != base_mem) { 4787 return this; // Many memory splits; no change 4788 } 4789 } 4790 } 4791 return base_mem; // No memory splits; ID on the one true input 4792 } 4793 4794 //------------------------------Ideal------------------------------------------ 4795 // This method is invoked recursively on chains of MergeMem nodes 4796 Node *MergeMemNode::Ideal(PhaseGVN *phase, bool can_reshape) { 4797 // Remove chain'd MergeMems 4798 // 4799 // This is delicate, because the each "in(i)" (i >= Raw) is interpreted 4800 // relative to the "in(Bot)". Since we are patching both at the same time, 4801 // we have to be careful to read each "in(i)" relative to the old "in(Bot)", 4802 // but rewrite each "in(i)" relative to the new "in(Bot)". 4803 Node *progress = NULL; 4804 4805 4806 Node* old_base = base_memory(); 4807 Node* empty_mem = empty_memory(); 4808 if (old_base == empty_mem) 4809 return NULL; // Dead memory path. 4810 4811 MergeMemNode* old_mbase; 4812 if (old_base != NULL && old_base->is_MergeMem()) 4813 old_mbase = old_base->as_MergeMem(); 4814 else 4815 old_mbase = NULL; 4816 Node* new_base = old_base; 4817 4818 // simplify stacked MergeMems in base memory 4819 if (old_mbase) new_base = old_mbase->base_memory(); 4820 4821 // the base memory might contribute new slices beyond my req() 4822 if (old_mbase) grow_to_match(old_mbase); 4823 4824 // Note: We do not call verify_sparse on entry, because inputs 4825 // can normalize to the base_memory via subsume_node or similar 4826 // mechanisms. This method repairs that damage. 4827 4828 assert(!old_mbase || old_mbase->is_empty_memory(empty_mem), "consistent sentinels"); 4829 4830 // Look at each slice. 4831 for (uint i = Compile::AliasIdxRaw; i < req(); i++) { 4832 Node* old_in = in(i); 4833 // calculate the old memory value 4834 Node* old_mem = old_in; 4835 if (old_mem == empty_mem) old_mem = old_base; 4836 assert(old_mem == memory_at(i), ""); 4837 4838 // maybe update (reslice) the old memory value 4839 4840 // simplify stacked MergeMems 4841 Node* new_mem = old_mem; 4842 MergeMemNode* old_mmem; 4843 if (old_mem != NULL && old_mem->is_MergeMem()) 4844 old_mmem = old_mem->as_MergeMem(); 4845 else 4846 old_mmem = NULL; 4847 if (old_mmem == this) { 4848 // This can happen if loops break up and safepoints disappear. 4849 // A merge of BotPtr (default) with a RawPtr memory derived from a 4850 // safepoint can be rewritten to a merge of the same BotPtr with 4851 // the BotPtr phi coming into the loop. If that phi disappears 4852 // also, we can end up with a self-loop of the mergemem. 4853 // In general, if loops degenerate and memory effects disappear, 4854 // a mergemem can be left looking at itself. This simply means 4855 // that the mergemem's default should be used, since there is 4856 // no longer any apparent effect on this slice. 4857 // Note: If a memory slice is a MergeMem cycle, it is unreachable 4858 // from start. Update the input to TOP. 4859 new_mem = (new_base == this || new_base == empty_mem)? empty_mem : new_base; 4860 } 4861 else if (old_mmem != NULL) { 4862 new_mem = old_mmem->memory_at(i); 4863 } 4864 // else preceding memory was not a MergeMem 4865 4866 // maybe store down a new value 4867 Node* new_in = new_mem; 4868 if (new_in == new_base) new_in = empty_mem; 4869 4870 if (new_in != old_in) { 4871 // Warning: Do not combine this "if" with the previous "if" 4872 // A memory slice might have be be rewritten even if it is semantically 4873 // unchanged, if the base_memory value has changed. 4874 set_req_X(i, new_in, phase); 4875 progress = this; // Report progress 4876 } 4877 } 4878 4879 if (new_base != old_base) { 4880 set_req_X(Compile::AliasIdxBot, new_base, phase); 4881 // Don't use set_base_memory(new_base), because we need to update du. 4882 assert(base_memory() == new_base, ""); 4883 progress = this; 4884 } 4885 4886 if( base_memory() == this ) { 4887 // a self cycle indicates this memory path is dead 4888 set_req(Compile::AliasIdxBot, empty_mem); 4889 } 4890 4891 // Resolve external cycles by calling Ideal on a MergeMem base_memory 4892 // Recursion must occur after the self cycle check above 4893 if( base_memory()->is_MergeMem() ) { 4894 MergeMemNode *new_mbase = base_memory()->as_MergeMem(); 4895 Node *m = phase->transform(new_mbase); // Rollup any cycles 4896 if( m != NULL && 4897 (m->is_top() || 4898 (m->is_MergeMem() && m->as_MergeMem()->base_memory() == empty_mem)) ) { 4899 // propagate rollup of dead cycle to self 4900 set_req(Compile::AliasIdxBot, empty_mem); 4901 } 4902 } 4903 4904 if( base_memory() == empty_mem ) { 4905 progress = this; 4906 // Cut inputs during Parse phase only. 4907 // During Optimize phase a dead MergeMem node will be subsumed by Top. 4908 if( !can_reshape ) { 4909 for (uint i = Compile::AliasIdxRaw; i < req(); i++) { 4910 if( in(i) != empty_mem ) { set_req(i, empty_mem); } 4911 } 4912 } 4913 } 4914 4915 if( !progress && base_memory()->is_Phi() && can_reshape ) { 4916 // Check if PhiNode::Ideal's "Split phis through memory merges" 4917 // transform should be attempted. Look for this->phi->this cycle. 4918 uint merge_width = req(); 4919 if (merge_width > Compile::AliasIdxRaw) { 4920 PhiNode* phi = base_memory()->as_Phi(); 4921 for( uint i = 1; i < phi->req(); ++i ) {// For all paths in 4922 if (phi->in(i) == this) { 4923 phase->is_IterGVN()->_worklist.push(phi); 4924 break; 4925 } 4926 } 4927 } 4928 } 4929 4930 assert(progress || verify_sparse(), "please, no dups of base"); 4931 return progress; 4932 } 4933 4934 //-------------------------set_base_memory------------------------------------- 4935 void MergeMemNode::set_base_memory(Node *new_base) { 4936 Node* empty_mem = empty_memory(); 4937 set_req(Compile::AliasIdxBot, new_base); 4938 assert(memory_at(req()) == new_base, "must set default memory"); 4939 // Clear out other occurrences of new_base: 4940 if (new_base != empty_mem) { 4941 for (uint i = Compile::AliasIdxRaw; i < req(); i++) { 4942 if (in(i) == new_base) set_req(i, empty_mem); 4943 } 4944 } 4945 } 4946 4947 //------------------------------out_RegMask------------------------------------ 4948 const RegMask &MergeMemNode::out_RegMask() const { 4949 return RegMask::Empty; 4950 } 4951 4952 //------------------------------dump_spec-------------------------------------- 4953 #ifndef PRODUCT 4954 void MergeMemNode::dump_spec(outputStream *st) const { 4955 st->print(" {"); 4956 Node* base_mem = base_memory(); 4957 for( uint i = Compile::AliasIdxRaw; i < req(); i++ ) { 4958 Node* mem = (in(i) != NULL) ? memory_at(i) : base_mem; 4959 if (mem == base_mem) { st->print(" -"); continue; } 4960 st->print( " N%d:", mem->_idx ); 4961 Compile::current()->get_adr_type(i)->dump_on(st); 4962 } 4963 st->print(" }"); 4964 } 4965 #endif // !PRODUCT 4966 4967 4968 #ifdef ASSERT 4969 static bool might_be_same(Node* a, Node* b) { 4970 if (a == b) return true; 4971 if (!(a->is_Phi() || b->is_Phi())) return false; 4972 // phis shift around during optimization 4973 return true; // pretty stupid... 4974 } 4975 4976 // verify a narrow slice (either incoming or outgoing) 4977 static void verify_memory_slice(const MergeMemNode* m, int alias_idx, Node* n) { 4978 if (!VerifyAliases) return; // don't bother to verify unless requested 4979 if (VMError::is_error_reported()) return; // muzzle asserts when debugging an error 4980 if (Node::in_dump()) return; // muzzle asserts when printing 4981 assert(alias_idx >= Compile::AliasIdxRaw, "must not disturb base_memory or sentinel"); 4982 assert(n != NULL, ""); 4983 // Elide intervening MergeMem's 4984 while (n->is_MergeMem()) { 4985 n = n->as_MergeMem()->memory_at(alias_idx); 4986 } 4987 Compile* C = Compile::current(); 4988 const TypePtr* n_adr_type = n->adr_type(); 4989 if (n == m->empty_memory()) { 4990 // Implicit copy of base_memory() 4991 } else if (n_adr_type != TypePtr::BOTTOM) { 4992 assert(n_adr_type != NULL, "new memory must have a well-defined adr_type"); 4993 assert(C->must_alias(n_adr_type, alias_idx), "new memory must match selected slice"); 4994 } else { 4995 // A few places like make_runtime_call "know" that VM calls are narrow, 4996 // and can be used to update only the VM bits stored as TypeRawPtr::BOTTOM. 4997 bool expected_wide_mem = false; 4998 if (n == m->base_memory()) { 4999 expected_wide_mem = true; 5000 } else if (alias_idx == Compile::AliasIdxRaw || 5001 n == m->memory_at(Compile::AliasIdxRaw)) { 5002 expected_wide_mem = true; 5003 } else if (!C->alias_type(alias_idx)->is_rewritable()) { 5004 // memory can "leak through" calls on channels that 5005 // are write-once. Allow this also. 5006 expected_wide_mem = true; 5007 } 5008 assert(expected_wide_mem, "expected narrow slice replacement"); 5009 } 5010 } 5011 #else // !ASSERT 5012 #define verify_memory_slice(m,i,n) (void)(0) // PRODUCT version is no-op 5013 #endif 5014 5015 5016 //-----------------------------memory_at--------------------------------------- 5017 Node* MergeMemNode::memory_at(uint alias_idx) const { 5018 assert(alias_idx >= Compile::AliasIdxRaw || 5019 alias_idx == Compile::AliasIdxBot && !Compile::current()->do_aliasing(), 5020 "must avoid base_memory and AliasIdxTop"); 5021 5022 // Otherwise, it is a narrow slice. 5023 Node* n = alias_idx < req() ? in(alias_idx) : empty_memory(); 5024 if (is_empty_memory(n)) { 5025 // the array is sparse; empty slots are the "top" node 5026 n = base_memory(); 5027 assert(Node::in_dump() 5028 || n == NULL || n->bottom_type() == Type::TOP 5029 || n->adr_type() == NULL // address is TOP 5030 || n->adr_type() == TypePtr::BOTTOM 5031 || n->adr_type() == TypeRawPtr::BOTTOM 5032 || !Compile::current()->do_aliasing(), 5033 "must be a wide memory"); 5034 // do_aliasing == false if we are organizing the memory states manually. 5035 // See verify_memory_slice for comments on TypeRawPtr::BOTTOM. 5036 } else { 5037 // make sure the stored slice is sane 5038 #ifdef ASSERT 5039 if (VMError::is_error_reported() || Node::in_dump()) { 5040 } else if (might_be_same(n, base_memory())) { 5041 // Give it a pass: It is a mostly harmless repetition of the base. 5042 // This can arise normally from node subsumption during optimization. 5043 } else { 5044 verify_memory_slice(this, alias_idx, n); 5045 } 5046 #endif 5047 } 5048 return n; 5049 } 5050 5051 //---------------------------set_memory_at------------------------------------- 5052 void MergeMemNode::set_memory_at(uint alias_idx, Node *n) { 5053 verify_memory_slice(this, alias_idx, n); 5054 Node* empty_mem = empty_memory(); 5055 if (n == base_memory()) n = empty_mem; // collapse default 5056 uint need_req = alias_idx+1; 5057 if (req() < need_req) { 5058 if (n == empty_mem) return; // already the default, so do not grow me 5059 // grow the sparse array 5060 do { 5061 add_req(empty_mem); 5062 } while (req() < need_req); 5063 } 5064 set_req( alias_idx, n ); 5065 } 5066 5067 5068 5069 //--------------------------iteration_setup------------------------------------ 5070 void MergeMemNode::iteration_setup(const MergeMemNode* other) { 5071 if (other != NULL) { 5072 grow_to_match(other); 5073 // invariant: the finite support of mm2 is within mm->req() 5074 #ifdef ASSERT 5075 for (uint i = req(); i < other->req(); i++) { 5076 assert(other->is_empty_memory(other->in(i)), "slice left uncovered"); 5077 } 5078 #endif 5079 } 5080 // Replace spurious copies of base_memory by top. 5081 Node* base_mem = base_memory(); 5082 if (base_mem != NULL && !base_mem->is_top()) { 5083 for (uint i = Compile::AliasIdxBot+1, imax = req(); i < imax; i++) { 5084 if (in(i) == base_mem) 5085 set_req(i, empty_memory()); 5086 } 5087 } 5088 } 5089 5090 //---------------------------grow_to_match------------------------------------- 5091 void MergeMemNode::grow_to_match(const MergeMemNode* other) { 5092 Node* empty_mem = empty_memory(); 5093 assert(other->is_empty_memory(empty_mem), "consistent sentinels"); 5094 // look for the finite support of the other memory 5095 for (uint i = other->req(); --i >= req(); ) { 5096 if (other->in(i) != empty_mem) { 5097 uint new_len = i+1; 5098 while (req() < new_len) add_req(empty_mem); 5099 break; 5100 } 5101 } 5102 } 5103 5104 //---------------------------verify_sparse------------------------------------- 5105 #ifndef PRODUCT 5106 bool MergeMemNode::verify_sparse() const { 5107 assert(is_empty_memory(make_empty_memory()), "sane sentinel"); 5108 Node* base_mem = base_memory(); 5109 // The following can happen in degenerate cases, since empty==top. 5110 if (is_empty_memory(base_mem)) return true; 5111 for (uint i = Compile::AliasIdxRaw; i < req(); i++) { 5112 assert(in(i) != NULL, "sane slice"); 5113 if (in(i) == base_mem) return false; // should have been the sentinel value! 5114 } 5115 return true; 5116 } 5117 5118 bool MergeMemStream::match_memory(Node* mem, const MergeMemNode* mm, int idx) { 5119 Node* n; 5120 n = mm->in(idx); 5121 if (mem == n) return true; // might be empty_memory() 5122 n = (idx == Compile::AliasIdxBot)? mm->base_memory(): mm->memory_at(idx); 5123 if (mem == n) return true; 5124 return false; 5125 } 5126 #endif // !PRODUCT