1 /*
   2  * Copyright (c) 2005, 2025, 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 "ci/ciFlatArrayKlass.hpp"
  26 #include "ci/ciInlineKlass.hpp"
  27 #include "ci/ciInstanceKlass.hpp"
  28 #include "compiler/compileLog.hpp"
  29 #include "gc/shared/collectedHeap.inline.hpp"
  30 #include "gc/shared/tlab_globals.hpp"
  31 #include "libadt/vectset.hpp"
  32 #include "memory/universe.hpp"
  33 #include "opto/addnode.hpp"
  34 #include "opto/arraycopynode.hpp"
  35 #include "opto/callnode.hpp"
  36 #include "opto/castnode.hpp"
  37 #include "opto/cfgnode.hpp"
  38 #include "opto/compile.hpp"
  39 #include "opto/convertnode.hpp"
  40 #include "opto/graphKit.hpp"
  41 #include "opto/inlinetypenode.hpp"
  42 #include "opto/intrinsicnode.hpp"
  43 #include "opto/locknode.hpp"
  44 #include "opto/loopnode.hpp"
  45 #include "opto/macro.hpp"
  46 #include "opto/memnode.hpp"
  47 #include "opto/narrowptrnode.hpp"
  48 #include "opto/node.hpp"
  49 #include "opto/opaquenode.hpp"
  50 #include "opto/opcodes.hpp"
  51 #include "opto/phaseX.hpp"
  52 #include "opto/rootnode.hpp"
  53 #include "opto/runtime.hpp"
  54 #include "opto/subnode.hpp"
  55 #include "opto/subtypenode.hpp"
  56 #include "opto/type.hpp"
  57 #include "prims/jvmtiExport.hpp"
  58 #include "runtime/continuation.hpp"
  59 #include "runtime/sharedRuntime.hpp"
  60 #include "runtime/stubRoutines.hpp"
  61 #include "utilities/globalDefinitions.hpp"
  62 #include "utilities/macros.hpp"
  63 #include "utilities/powerOfTwo.hpp"
  64 #if INCLUDE_G1GC
  65 #include "gc/g1/g1ThreadLocalData.hpp"
  66 #endif // INCLUDE_G1GC
  67 
  68 
  69 //
  70 // Replace any references to "oldref" in inputs to "use" with "newref".
  71 // Returns the number of replacements made.
  72 //
  73 int PhaseMacroExpand::replace_input(Node *use, Node *oldref, Node *newref) {
  74   int nreplacements = 0;
  75   uint req = use->req();
  76   for (uint j = 0; j < use->len(); j++) {
  77     Node *uin = use->in(j);
  78     if (uin == oldref) {
  79       if (j < req)
  80         use->set_req(j, newref);
  81       else
  82         use->set_prec(j, newref);
  83       nreplacements++;
  84     } else if (j >= req && uin == nullptr) {
  85       break;
  86     }
  87   }
  88   return nreplacements;
  89 }
  90 
  91 
  92 Node* PhaseMacroExpand::opt_bits_test(Node* ctrl, Node* region, int edge, Node* word) {
  93   Node* cmp = word;
  94   Node* bol = transform_later(new BoolNode(cmp, BoolTest::ne));
  95   IfNode* iff = new IfNode( ctrl, bol, PROB_MIN, COUNT_UNKNOWN );
  96   transform_later(iff);
  97 
  98   // Fast path taken.
  99   Node *fast_taken = transform_later(new IfFalseNode(iff));
 100 
 101   // Fast path not-taken, i.e. slow path
 102   Node *slow_taken = transform_later(new IfTrueNode(iff));
 103 
 104     region->init_req(edge, fast_taken); // Capture fast-control
 105     return slow_taken;
 106 }
 107 
 108 //--------------------copy_predefined_input_for_runtime_call--------------------
 109 void PhaseMacroExpand::copy_predefined_input_for_runtime_call(Node * ctrl, CallNode* oldcall, CallNode* call) {
 110   // Set fixed predefined input arguments
 111   call->init_req( TypeFunc::Control, ctrl );
 112   call->init_req( TypeFunc::I_O    , oldcall->in( TypeFunc::I_O) );
 113   call->init_req( TypeFunc::Memory , oldcall->in( TypeFunc::Memory ) ); // ?????
 114   call->init_req( TypeFunc::ReturnAdr, oldcall->in( TypeFunc::ReturnAdr ) );
 115   call->init_req( TypeFunc::FramePtr, oldcall->in( TypeFunc::FramePtr ) );
 116 }
 117 
 118 //------------------------------make_slow_call---------------------------------
 119 CallNode* PhaseMacroExpand::make_slow_call(CallNode *oldcall, const TypeFunc* slow_call_type,
 120                                            address slow_call, const char* leaf_name, Node* slow_path,
 121                                            Node* parm0, Node* parm1, Node* parm2) {
 122 
 123   // Slow-path call
 124  CallNode *call = leaf_name
 125    ? (CallNode*)new CallLeafNode      ( slow_call_type, slow_call, leaf_name, TypeRawPtr::BOTTOM )
 126    : (CallNode*)new CallStaticJavaNode( slow_call_type, slow_call, OptoRuntime::stub_name(slow_call), TypeRawPtr::BOTTOM );
 127 
 128   // Slow path call has no side-effects, uses few values
 129   copy_predefined_input_for_runtime_call(slow_path, oldcall, call );
 130   if (parm0 != nullptr)  call->init_req(TypeFunc::Parms+0, parm0);
 131   if (parm1 != nullptr)  call->init_req(TypeFunc::Parms+1, parm1);
 132   if (parm2 != nullptr)  call->init_req(TypeFunc::Parms+2, parm2);
 133   call->copy_call_debug_info(&_igvn, oldcall);
 134   call->set_cnt(PROB_UNLIKELY_MAG(4));  // Same effect as RC_UNCOMMON.
 135   _igvn.replace_node(oldcall, call);
 136   transform_later(call);
 137 
 138   return call;
 139 }
 140 
 141 void PhaseMacroExpand::eliminate_gc_barrier(Node* p2x) {
 142   BarrierSetC2 *bs = BarrierSet::barrier_set()->barrier_set_c2();
 143   bs->eliminate_gc_barrier(&_igvn, p2x);
 144 #ifndef PRODUCT
 145   if (PrintOptoStatistics) {
 146     AtomicAccess::inc(&PhaseMacroExpand::_GC_barriers_removed_counter);
 147   }
 148 #endif
 149 }
 150 
 151 // Search for a memory operation for the specified memory slice.
 152 static Node *scan_mem_chain(Node *mem, int alias_idx, int offset, Node *start_mem, Node *alloc, PhaseGVN *phase) {
 153   Node *orig_mem = mem;
 154   Node *alloc_mem = alloc->as_Allocate()->proj_out_or_null(TypeFunc::Memory, /*io_use:*/false);
 155   assert(alloc_mem != nullptr, "Allocation without a memory projection.");
 156   const TypeOopPtr *tinst = phase->C->get_adr_type(alias_idx)->isa_oopptr();
 157   while (true) {
 158     if (mem == alloc_mem || mem == start_mem ) {
 159       return mem;  // hit one of our sentinels
 160     } else if (mem->is_MergeMem()) {
 161       mem = mem->as_MergeMem()->memory_at(alias_idx);
 162     } else if (mem->is_Proj() && mem->as_Proj()->_con == TypeFunc::Memory) {
 163       Node *in = mem->in(0);
 164       // we can safely skip over safepoints, calls, locks and membars because we
 165       // already know that the object is safe to eliminate.
 166       if (in->is_Initialize() && in->as_Initialize()->allocation() == alloc) {
 167         return in;
 168       } else if (in->is_Call()) {
 169         CallNode *call = in->as_Call();
 170         if (call->may_modify(tinst, phase)) {
 171           assert(call->is_ArrayCopy(), "ArrayCopy is the only call node that doesn't make allocation escape");
 172           if (call->as_ArrayCopy()->modifies(offset, offset, phase, false)) {
 173             return in;
 174           }
 175         }
 176         mem = in->in(TypeFunc::Memory);
 177       } else if (in->is_MemBar()) {
 178         ArrayCopyNode* ac = nullptr;
 179         if (ArrayCopyNode::may_modify(tinst, in->as_MemBar(), phase, ac)) {
 180           if (ac != nullptr) {
 181             assert(ac->is_clonebasic(), "Only basic clone is a non escaping clone");
 182             return ac;
 183           }
 184         }
 185         mem = in->in(TypeFunc::Memory);
 186       } else if (in->is_LoadFlat() || in->is_StoreFlat()) {
 187         mem = in->in(TypeFunc::Memory);
 188       } else {
 189 #ifdef ASSERT
 190         in->dump();
 191         mem->dump();
 192         assert(false, "unexpected projection");
 193 #endif
 194       }
 195     } else if (mem->is_Store()) {
 196       const TypePtr* atype = mem->as_Store()->adr_type();
 197       int adr_idx = phase->C->get_alias_index(atype);
 198       if (adr_idx == alias_idx) {
 199         assert(atype->isa_oopptr(), "address type must be oopptr");
 200         int adr_offset = atype->flat_offset();
 201         uint adr_iid = atype->is_oopptr()->instance_id();
 202         // Array elements references have the same alias_idx
 203         // but different offset and different instance_id.
 204         if (adr_offset == offset && adr_iid == alloc->_idx) {
 205           return mem;
 206         }
 207       } else {
 208         assert(adr_idx == Compile::AliasIdxRaw, "address must match or be raw");
 209       }
 210       mem = mem->in(MemNode::Memory);
 211     } else if (mem->is_ClearArray()) {
 212       if (!ClearArrayNode::step_through(&mem, alloc->_idx, phase)) {
 213         // Can not bypass initialization of the instance
 214         // we are looking.
 215         DEBUG_ONLY(intptr_t offset;)
 216         assert(alloc == AllocateNode::Ideal_allocation(mem->in(3), phase, offset), "sanity");
 217         InitializeNode* init = alloc->as_Allocate()->initialization();
 218         // We are looking for stored value, return Initialize node
 219         // or memory edge from Allocate node.
 220         if (init != nullptr) {
 221           return init;
 222         } else {
 223           return alloc->in(TypeFunc::Memory); // It will produce zero value (see callers).
 224         }
 225       }
 226       // Otherwise skip it (the call updated 'mem' value).
 227     } else if (mem->Opcode() == Op_SCMemProj) {
 228       mem = mem->in(0);
 229       Node* adr = nullptr;
 230       if (mem->is_LoadStore()) {
 231         adr = mem->in(MemNode::Address);
 232       } else {
 233         assert(mem->Opcode() == Op_EncodeISOArray ||
 234                mem->Opcode() == Op_StrCompressedCopy, "sanity");
 235         adr = mem->in(3); // Destination array
 236       }
 237       const TypePtr* atype = adr->bottom_type()->is_ptr();
 238       int adr_idx = phase->C->get_alias_index(atype);
 239       if (adr_idx == alias_idx) {
 240         DEBUG_ONLY(mem->dump();)
 241         assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
 242         return nullptr;
 243       }
 244       mem = mem->in(MemNode::Memory);
 245     } else if (mem->Opcode() == Op_StrInflatedCopy) {
 246       Node* adr = mem->in(3); // Destination array
 247       const TypePtr* atype = adr->bottom_type()->is_ptr();
 248       int adr_idx = phase->C->get_alias_index(atype);
 249       if (adr_idx == alias_idx) {
 250         DEBUG_ONLY(mem->dump();)
 251         assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
 252         return nullptr;
 253       }
 254       mem = mem->in(MemNode::Memory);
 255     } else {
 256       return mem;
 257     }
 258     assert(mem != orig_mem, "dead memory loop");
 259   }
 260 }
 261 
 262 // Generate loads from source of the arraycopy for fields of
 263 // destination needed at a deoptimization point
 264 Node* PhaseMacroExpand::make_arraycopy_load(ArrayCopyNode* ac, intptr_t offset, Node* ctl, Node* mem, BasicType ft, const Type *ftype, AllocateNode *alloc) {
 265   BasicType bt = ft;
 266   const Type *type = ftype;
 267   if (ft == T_NARROWOOP) {
 268     bt = T_OBJECT;
 269     type = ftype->make_oopptr();
 270   }
 271   Node* res = nullptr;
 272   if (ac->is_clonebasic()) {
 273     assert(ac->in(ArrayCopyNode::Src) != ac->in(ArrayCopyNode::Dest), "clone source equals destination");
 274     Node* base = ac->in(ArrayCopyNode::Src);
 275     Node* adr = _igvn.transform(new AddPNode(base, base, _igvn.MakeConX(offset)));
 276     const TypePtr* adr_type = _igvn.type(base)->is_ptr()->add_offset(offset);
 277     MergeMemNode* mergemen = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
 278     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 279     res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemen, adr, adr_type, type, bt);
 280   } else {
 281     if (ac->modifies(offset, offset, &_igvn, true)) {
 282       assert(ac->in(ArrayCopyNode::Dest) == alloc->result_cast(), "arraycopy destination should be allocation's result");
 283       uint shift = exact_log2(type2aelembytes(bt));
 284       Node* src_pos = ac->in(ArrayCopyNode::SrcPos);
 285       Node* dest_pos = ac->in(ArrayCopyNode::DestPos);
 286       const TypeInt* src_pos_t = _igvn.type(src_pos)->is_int();
 287       const TypeInt* dest_pos_t = _igvn.type(dest_pos)->is_int();
 288 
 289       Node* adr = nullptr;
 290       Node* base = ac->in(ArrayCopyNode::Src);
 291       const TypeAryPtr* adr_type = _igvn.type(base)->is_aryptr();
 292       if (adr_type->is_flat()) {
 293         shift = adr_type->flat_log_elem_size();
 294       }
 295       if (src_pos_t->is_con() && dest_pos_t->is_con()) {
 296         intptr_t off = ((src_pos_t->get_con() - dest_pos_t->get_con()) << shift) + offset;
 297         adr = _igvn.transform(new AddPNode(base, base, _igvn.MakeConX(off)));
 298         adr_type = _igvn.type(adr)->is_aryptr();
 299         assert(adr_type == _igvn.type(base)->is_aryptr()->add_field_offset_and_offset(off), "incorrect address type");
 300         if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
 301           // Don't emit a new load from src if src == dst but try to get the value from memory instead
 302           return value_from_mem(ac->in(TypeFunc::Memory), ctl, ft, ftype, adr_type, alloc);
 303         }
 304       } else {
 305         if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
 306           // Non constant offset in the array: we can't statically
 307           // determine the value
 308           return nullptr;
 309         }
 310         Node* diff = _igvn.transform(new SubINode(ac->in(ArrayCopyNode::SrcPos), ac->in(ArrayCopyNode::DestPos)));
 311 #ifdef _LP64
 312         diff = _igvn.transform(new ConvI2LNode(diff));
 313 #endif
 314         diff = _igvn.transform(new LShiftXNode(diff, _igvn.intcon(shift)));
 315 
 316         Node* off = _igvn.transform(new AddXNode(_igvn.MakeConX(offset), diff));
 317         adr = _igvn.transform(new AddPNode(base, base, off));
 318         // In the case of a flat inline type array, each field has its
 319         // own slice so we need to extract the field being accessed from
 320         // the address computation
 321         adr_type = adr_type->add_field_offset_and_offset(offset)->add_offset(Type::OffsetBot)->is_aryptr();
 322         adr = _igvn.transform(new CastPPNode(ctl, adr, adr_type));
 323       }
 324       MergeMemNode* mergemen = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
 325       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 326       res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemen, adr, adr_type, type, bt);
 327     }
 328   }
 329   if (res != nullptr) {
 330     if (ftype->isa_narrowoop()) {
 331       // PhaseMacroExpand::scalar_replacement adds DecodeN nodes
 332       assert(res->isa_DecodeN(), "should be narrow oop");
 333       res = _igvn.transform(new EncodePNode(res, ftype));
 334     }
 335     return res;
 336   }
 337   return nullptr;
 338 }
 339 
 340 //
 341 // Given a Memory Phi, compute a value Phi containing the values from stores
 342 // on the input paths.
 343 // Note: this function is recursive, its depth is limited by the "level" argument
 344 // Returns the computed Phi, or null if it cannot compute it.
 345 Node *PhaseMacroExpand::value_from_mem_phi(Node *mem, BasicType ft, const Type *phi_type, const TypeOopPtr *adr_t, AllocateNode *alloc, Node_Stack *value_phis, int level) {
 346   assert(mem->is_Phi(), "sanity");
 347   int alias_idx = C->get_alias_index(adr_t);
 348   int offset = adr_t->flat_offset();
 349   int instance_id = adr_t->instance_id();
 350 
 351   // Check if an appropriate value phi already exists.
 352   Node* region = mem->in(0);
 353   for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) {
 354     Node* phi = region->fast_out(k);
 355     if (phi->is_Phi() && phi != mem &&
 356         phi->as_Phi()->is_same_inst_field(phi_type, (int)mem->_idx, instance_id, alias_idx, offset)) {
 357       return phi;
 358     }
 359   }
 360   // Check if an appropriate new value phi already exists.
 361   Node* new_phi = value_phis->find(mem->_idx);
 362   if (new_phi != nullptr)
 363     return new_phi;
 364 
 365   if (level <= 0) {
 366     return nullptr; // Give up: phi tree too deep
 367   }
 368   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
 369   Node *alloc_mem = alloc->proj_out_or_null(TypeFunc::Memory, /*io_use:*/false);
 370   assert(alloc_mem != nullptr, "Allocation without a memory projection.");
 371 
 372   uint length = mem->req();
 373   GrowableArray <Node *> values(length, length, nullptr);
 374 
 375   // create a new Phi for the value
 376   PhiNode *phi = new PhiNode(mem->in(0), phi_type, nullptr, mem->_idx, instance_id, alias_idx, offset);
 377   transform_later(phi);
 378   value_phis->push(phi, mem->_idx);
 379 
 380   for (uint j = 1; j < length; j++) {
 381     Node *in = mem->in(j);
 382     if (in == nullptr || in->is_top()) {
 383       values.at_put(j, in);
 384     } else {
 385       Node *val = scan_mem_chain(in, alias_idx, offset, start_mem, alloc, &_igvn);
 386       if (val == start_mem || val == alloc_mem) {
 387         // hit a sentinel, return appropriate value
 388         Node* init_value = value_from_alloc(ft, adr_t, alloc);
 389         if (init_value == nullptr) {
 390           return nullptr;
 391         } else {
 392           values.at_put(j, init_value);
 393           continue;
 394         }
 395       }
 396       if (val->is_Initialize()) {
 397         val = val->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
 398       }
 399       if (val == nullptr) {
 400         return nullptr;  // can't find a value on this path
 401       }
 402       if (val == mem) {
 403         values.at_put(j, mem);
 404       } else if (val->is_Store()) {
 405         Node* n = val->in(MemNode::ValueIn);
 406         BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 407         n = bs->step_over_gc_barrier(n);
 408         if (is_subword_type(ft)) {
 409           n = Compile::narrow_value(ft, n, phi_type, &_igvn, true);
 410         }
 411         values.at_put(j, n);
 412       } else if (val->is_Proj() && val->in(0) == alloc) {
 413         Node* init_value = value_from_alloc(ft, adr_t, alloc);
 414         if (init_value == nullptr) {
 415           return nullptr;
 416         } else {
 417           values.at_put(j, init_value);
 418         }
 419       } else if (val->is_Phi()) {
 420         val = value_from_mem_phi(val, ft, phi_type, adr_t, alloc, value_phis, level-1);
 421         if (val == nullptr) {
 422           return nullptr;
 423         }
 424         values.at_put(j, val);
 425       } else if (val->Opcode() == Op_SCMemProj) {
 426         assert(val->in(0)->is_LoadStore() ||
 427                val->in(0)->Opcode() == Op_EncodeISOArray ||
 428                val->in(0)->Opcode() == Op_StrCompressedCopy, "sanity");
 429         assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
 430         return nullptr;
 431       } else if (val->is_ArrayCopy()) {
 432         Node* res = make_arraycopy_load(val->as_ArrayCopy(), offset, val->in(0), val->in(TypeFunc::Memory), ft, phi_type, alloc);
 433         if (res == nullptr) {
 434           return nullptr;
 435         }
 436         values.at_put(j, res);
 437       } else if (val->is_top()) {
 438         // This indicates that this path into the phi is dead. Top will eventually also propagate into the Region.
 439         // IGVN will clean this up later.
 440         values.at_put(j, val);
 441       } else {
 442         DEBUG_ONLY( val->dump(); )
 443         assert(false, "unknown node on this path");
 444         return nullptr;  // unknown node on this path
 445       }
 446     }
 447   }
 448   // Set Phi's inputs
 449   for (uint j = 1; j < length; j++) {
 450     if (values.at(j) == mem) {
 451       phi->init_req(j, phi);
 452     } else {
 453       phi->init_req(j, values.at(j));
 454     }
 455   }
 456   return phi;
 457 }
 458 
 459 // Extract the initial value of a field in an allocation
 460 Node* PhaseMacroExpand::value_from_alloc(BasicType ft, const TypeOopPtr* adr_t, AllocateNode* alloc) {
 461   Node* init_value = alloc->in(AllocateNode::InitValue);
 462   if (init_value == nullptr) {
 463     assert(alloc->in(AllocateNode::RawInitValue) == nullptr, "conflicting InitValue and RawInitValue");
 464     return _igvn.zerocon(ft);
 465   }
 466 
 467   const TypeAryPtr* ary_t = adr_t->isa_aryptr();
 468   assert(ary_t != nullptr, "must be a pointer into an array");
 469 
 470   // If this is not a flat array, then it must be an oop array with elements being init_value
 471   if (ary_t->is_not_flat()) {
 472 #ifdef ASSERT
 473     BasicType init_bt = init_value->bottom_type()->basic_type();
 474     assert(ft == init_bt ||
 475            (!is_java_primitive(ft) && !is_java_primitive(init_bt) && type2aelembytes(ft, true) == type2aelembytes(init_bt, true)) ||
 476            (is_subword_type(ft) && init_bt == T_INT),
 477            "invalid init_value of type %s for field of type %s", type2name(init_bt), type2name(ft));
 478 #endif // ASSERT
 479     return init_value;
 480   }
 481 
 482   assert(ary_t->klass_is_exact() && ary_t->is_flat(), "must be an exact flat array");
 483   assert(ary_t->field_offset().get() != Type::OffsetBot, "unknown offset");
 484   if (init_value->is_EncodeP()) {
 485     init_value = init_value->in(1);
 486   }
 487   // Cannot look through init_value if it is an oop
 488   if (!init_value->is_InlineType()) {
 489     return nullptr;
 490   }
 491 
 492   ciInlineKlass* vk = init_value->bottom_type()->inline_klass();
 493   if (ary_t->field_offset().get() == vk->null_marker_offset_in_payload()) {
 494     init_value = init_value->as_InlineType()->get_null_marker();
 495   } else {
 496     init_value = init_value->as_InlineType()->field_value_by_offset(ary_t->field_offset().get() + vk->payload_offset(), true);
 497   }
 498 
 499   if (ft == T_NARROWOOP) {
 500     assert(init_value->bottom_type()->isa_ptr(), "must be a pointer");
 501     init_value = transform_later(new EncodePNode(init_value, init_value->bottom_type()->make_narrowoop()));
 502   }
 503 
 504 #ifdef ASSERT
 505   BasicType init_bt = init_value->bottom_type()->basic_type();
 506   assert(ft == init_bt ||
 507          (!is_java_primitive(ft) && !is_java_primitive(init_bt) && type2aelembytes(ft, true) == type2aelembytes(init_bt, true)) ||
 508          (is_subword_type(ft) && init_bt == T_INT),
 509          "invalid init_value of type %s for field of type %s", type2name(init_bt), type2name(ft));
 510 #endif // ASSERT
 511 
 512   return init_value;
 513 }
 514 
 515 // Search the last value stored into the object's field.
 516 Node *PhaseMacroExpand::value_from_mem(Node *sfpt_mem, Node *sfpt_ctl, BasicType ft, const Type *ftype, const TypeOopPtr *adr_t, AllocateNode *alloc) {
 517   assert(adr_t->is_known_instance_field(), "instance required");
 518   int instance_id = adr_t->instance_id();
 519   assert((uint)instance_id == alloc->_idx, "wrong allocation");
 520 
 521   int alias_idx = C->get_alias_index(adr_t);
 522   int offset = adr_t->flat_offset();
 523   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
 524   Node *alloc_mem = alloc->proj_out_or_null(TypeFunc::Memory, /*io_use:*/false);
 525   assert(alloc_mem != nullptr, "Allocation without a memory projection.");
 526   VectorSet visited;
 527 
 528   bool done = sfpt_mem == alloc_mem;
 529   Node *mem = sfpt_mem;
 530   while (!done) {
 531     if (visited.test_set(mem->_idx)) {
 532       return nullptr;  // found a loop, give up
 533     }
 534     mem = scan_mem_chain(mem, alias_idx, offset, start_mem, alloc, &_igvn);
 535     if (mem == start_mem || mem == alloc_mem) {
 536       done = true;  // hit a sentinel, return appropriate 0 value
 537     } else if (mem->is_Initialize()) {
 538       mem = mem->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
 539       if (mem == nullptr) {
 540         done = true; // Something went wrong.
 541       } else if (mem->is_Store()) {
 542         const TypePtr* atype = mem->as_Store()->adr_type();
 543         assert(C->get_alias_index(atype) == Compile::AliasIdxRaw, "store is correct memory slice");
 544         done = true;
 545       }
 546     } else if (mem->is_Store()) {
 547       const TypeOopPtr* atype = mem->as_Store()->adr_type()->isa_oopptr();
 548       assert(atype != nullptr, "address type must be oopptr");
 549       assert(C->get_alias_index(atype) == alias_idx &&
 550              atype->is_known_instance_field() && atype->flat_offset() == offset &&
 551              atype->instance_id() == instance_id, "store is correct memory slice");
 552       done = true;
 553     } else if (mem->is_Phi()) {
 554       // try to find a phi's unique input
 555       Node *unique_input = nullptr;
 556       Node *top = C->top();
 557       for (uint i = 1; i < mem->req(); i++) {
 558         Node *n = scan_mem_chain(mem->in(i), alias_idx, offset, start_mem, alloc, &_igvn);
 559         if (n == nullptr || n == top || n == mem) {
 560           continue;
 561         } else if (unique_input == nullptr) {
 562           unique_input = n;
 563         } else if (unique_input != n) {
 564           unique_input = top;
 565           break;
 566         }
 567       }
 568       if (unique_input != nullptr && unique_input != top) {
 569         mem = unique_input;
 570       } else {
 571         done = true;
 572       }
 573     } else if (mem->is_ArrayCopy()) {
 574       done = true;
 575     } else if (mem->is_top()) {
 576       // The slice is on a dead path. Returning nullptr would lead to elimination
 577       // bailout, but we want to prevent that. Just forwarding the top is also legal,
 578       // and IGVN can just clean things up, and remove whatever receives top.
 579       return mem;
 580     } else {
 581       DEBUG_ONLY( mem->dump(); )
 582       assert(false, "unexpected node");
 583     }
 584   }
 585   if (mem != nullptr) {
 586     if (mem == start_mem || mem == alloc_mem) {
 587       // hit a sentinel, return appropriate value
 588       return value_from_alloc(ft, adr_t, alloc);
 589     } else if (mem->is_Store()) {
 590       Node* n = mem->in(MemNode::ValueIn);
 591       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 592       n = bs->step_over_gc_barrier(n);
 593       return n;
 594     } else if (mem->is_Phi()) {
 595       // attempt to produce a Phi reflecting the values on the input paths of the Phi
 596       Node_Stack value_phis(8);
 597       Node* phi = value_from_mem_phi(mem, ft, ftype, adr_t, alloc, &value_phis, ValueSearchLimit);
 598       if (phi != nullptr) {
 599         return phi;
 600       } else {
 601         // Kill all new Phis
 602         while(value_phis.is_nonempty()) {
 603           Node* n = value_phis.node();
 604           _igvn.replace_node(n, C->top());
 605           value_phis.pop();
 606         }
 607       }
 608     } else if (mem->is_ArrayCopy()) {
 609       Node* ctl = mem->in(0);
 610       Node* m = mem->in(TypeFunc::Memory);
 611       if (sfpt_ctl->is_Proj() && sfpt_ctl->as_Proj()->is_uncommon_trap_proj()) {
 612         // pin the loads in the uncommon trap path
 613         ctl = sfpt_ctl;
 614         m = sfpt_mem;
 615       }
 616       return make_arraycopy_load(mem->as_ArrayCopy(), offset, ctl, m, ft, ftype, alloc);
 617     }
 618   }
 619   // Something went wrong.
 620   return nullptr;
 621 }
 622 
 623 // Search the last value stored into the inline type's fields (for flat arrays).
 624 Node* PhaseMacroExpand::inline_type_from_mem(ciInlineKlass* vk, const TypeAryPtr* elem_adr_type, int elem_idx, int offset_in_element, bool null_free, AllocateNode* alloc, SafePointNode* sfpt) {
 625   auto report_failure = [&](int field_offset_in_element) {
 626 #ifndef PRODUCT
 627     if (PrintEliminateAllocations) {
 628       ciInlineKlass* elem_klass = elem_adr_type->elem()->inline_klass();
 629       int offset = field_offset_in_element + elem_klass->payload_offset();
 630       ciField* flattened_field = elem_klass->get_field_by_offset(offset, false);
 631       assert(flattened_field != nullptr, "must have a field of type %s at offset %d", elem_klass->name()->as_utf8(), offset);
 632       tty->print("=== At SafePoint node %d can't find value of field [%s] of array element [%d]", sfpt->_idx, flattened_field->name()->as_utf8(), elem_idx);
 633       tty->print(", which prevents elimination of: ");
 634       alloc->dump();
 635     }
 636 #endif // PRODUCT
 637   };
 638 
 639   // Create a new InlineTypeNode and retrieve the field values from memory
 640   InlineTypeNode* vt = InlineTypeNode::make_uninitialized(_igvn, vk, false);
 641   transform_later(vt);
 642   if (null_free) {
 643     vt->set_null_marker(_igvn);
 644   } else {
 645     int nm_offset_in_element = offset_in_element + vk->null_marker_offset_in_payload();
 646     const TypeAryPtr* nm_adr_type = elem_adr_type->with_field_offset(nm_offset_in_element);
 647     Node* nm_value = value_from_mem(sfpt->memory(), sfpt->control(), T_BOOLEAN, TypeInt::BOOL, nm_adr_type, alloc);
 648     if (nm_value != nullptr) {
 649       vt->set_null_marker(_igvn, nm_value);
 650     } else {
 651       report_failure(nm_offset_in_element);
 652       return nullptr;
 653     }
 654   }
 655 
 656   for (int i = 0; i < vk->nof_declared_nonstatic_fields(); ++i) {
 657     ciType* field_type = vt->field_type(i);
 658     int field_offset_in_element = offset_in_element + vt->field_offset(i) - vk->payload_offset();
 659     Node* field_value = nullptr;
 660     if (vt->field_is_flat(i)) {
 661       field_value = inline_type_from_mem(field_type->as_inline_klass(), elem_adr_type, elem_idx, field_offset_in_element, vt->field_is_null_free(i), alloc, sfpt);
 662     } else {
 663       const Type* ft = Type::get_const_type(field_type);
 664       BasicType bt = type2field[field_type->basic_type()];
 665       if (UseCompressedOops && !is_java_primitive(bt)) {
 666         ft = ft->make_narrowoop();
 667         bt = T_NARROWOOP;
 668       }
 669       // Each inline type field has its own memory slice
 670       const TypeAryPtr* field_adr_type = elem_adr_type->with_field_offset(field_offset_in_element);
 671       field_value = value_from_mem(sfpt->memory(), sfpt->control(), bt, ft, field_adr_type, alloc);
 672       if (field_value == nullptr) {
 673         report_failure(field_offset_in_element);
 674       } else if (ft->isa_narrowoop()) {
 675         assert(UseCompressedOops, "unexpected narrow oop");
 676         if (field_value->is_EncodeP()) {
 677           field_value = field_value->in(1);
 678         } else if (!field_value->is_InlineType()) {
 679           field_value = transform_later(new DecodeNNode(field_value, field_value->get_ptr_type()));
 680         }
 681       }
 682     }
 683     if (field_value != nullptr) {
 684       vt->set_field_value(i, field_value);
 685     } else {
 686       return nullptr;
 687     }
 688   }
 689   return vt;
 690 }
 691 
 692 // Check the possibility of scalar replacement.
 693 bool PhaseMacroExpand::can_eliminate_allocation(PhaseIterGVN* igvn, AllocateNode *alloc, GrowableArray <SafePointNode *>* safepoints) {
 694   //  Scan the uses of the allocation to check for anything that would
 695   //  prevent us from eliminating it.
 696   NOT_PRODUCT( const char* fail_eliminate = nullptr; )
 697   DEBUG_ONLY( Node* disq_node = nullptr; )
 698   bool can_eliminate = true;
 699   bool reduce_merge_precheck = (safepoints == nullptr);
 700 
 701   Unique_Node_List worklist;
 702   Node* res = alloc->result_cast();
 703   const TypeOopPtr* res_type = nullptr;
 704   if (res == nullptr) {
 705     // All users were eliminated.
 706   } else if (!res->is_CheckCastPP()) {
 707     NOT_PRODUCT(fail_eliminate = "Allocation does not have unique CheckCastPP";)
 708     can_eliminate = false;
 709   } else {
 710     worklist.push(res);
 711     res_type = igvn->type(res)->isa_oopptr();
 712     if (res_type == nullptr) {
 713       NOT_PRODUCT(fail_eliminate = "Neither instance or array allocation";)
 714       can_eliminate = false;
 715     } else if (!res_type->klass_is_exact()) {
 716       NOT_PRODUCT(fail_eliminate = "Not an exact type.";)
 717       can_eliminate = false;
 718     } else if (res_type->isa_aryptr()) {
 719       int length = alloc->in(AllocateNode::ALength)->find_int_con(-1);
 720       if (length < 0) {
 721         NOT_PRODUCT(fail_eliminate = "Array's size is not constant";)
 722         can_eliminate = false;
 723       }
 724     }
 725   }
 726 
 727   while (can_eliminate && worklist.size() > 0) {
 728     BarrierSetC2 *bs = BarrierSet::barrier_set()->barrier_set_c2();
 729     res = worklist.pop();
 730     for (DUIterator_Fast jmax, j = res->fast_outs(jmax); j < jmax && can_eliminate; j++) {
 731       Node* use = res->fast_out(j);
 732 
 733       if (use->is_AddP()) {
 734         const TypePtr* addp_type = igvn->type(use)->is_ptr();
 735         int offset = addp_type->offset();
 736 
 737         if (offset == Type::OffsetTop || offset == Type::OffsetBot) {
 738           NOT_PRODUCT(fail_eliminate = "Undefined field reference";)
 739           can_eliminate = false;
 740           break;
 741         }
 742         for (DUIterator_Fast kmax, k = use->fast_outs(kmax);
 743                                    k < kmax && can_eliminate; k++) {
 744           Node* n = use->fast_out(k);
 745           if ((n->is_Mem() && n->as_Mem()->is_mismatched_access()) || n->is_LoadFlat() || n->is_StoreFlat()) {
 746             DEBUG_ONLY(disq_node = n);
 747             NOT_PRODUCT(fail_eliminate = "Mismatched access");
 748             can_eliminate = false;
 749           }
 750           if (!n->is_Store() && n->Opcode() != Op_CastP2X && !bs->is_gc_pre_barrier_node(n) && !reduce_merge_precheck) {
 751             DEBUG_ONLY(disq_node = n;)
 752             if (n->is_Load() || n->is_LoadStore()) {
 753               NOT_PRODUCT(fail_eliminate = "Field load";)
 754             } else {
 755               NOT_PRODUCT(fail_eliminate = "Not store field reference";)
 756             }
 757             can_eliminate = false;
 758           }
 759         }
 760       } else if (use->is_ArrayCopy() &&
 761                  (use->as_ArrayCopy()->is_clonebasic() ||
 762                   use->as_ArrayCopy()->is_arraycopy_validated() ||
 763                   use->as_ArrayCopy()->is_copyof_validated() ||
 764                   use->as_ArrayCopy()->is_copyofrange_validated()) &&
 765                  use->in(ArrayCopyNode::Dest) == res) {
 766         // ok to eliminate
 767       } else if (use->is_SafePoint()) {
 768         SafePointNode* sfpt = use->as_SafePoint();
 769         if (sfpt->is_Call() && sfpt->as_Call()->has_non_debug_use(res)) {
 770           // Object is passed as argument.
 771           DEBUG_ONLY(disq_node = use;)
 772           NOT_PRODUCT(fail_eliminate = "Object is passed as argument";)
 773           can_eliminate = false;
 774         }
 775         Node* sfptMem = sfpt->memory();
 776         if (sfptMem == nullptr || sfptMem->is_top()) {
 777           DEBUG_ONLY(disq_node = use;)
 778           NOT_PRODUCT(fail_eliminate = "null or TOP memory";)
 779           can_eliminate = false;
 780         } else if (!reduce_merge_precheck) {
 781           assert(!res->is_Phi() || !res->as_Phi()->can_be_inline_type(), "Inline type allocations should not have safepoint uses");
 782           safepoints->append_if_missing(sfpt);
 783         }
 784       } else if (use->is_InlineType() && use->as_InlineType()->get_oop() == res) {
 785         // Look at uses
 786         for (DUIterator_Fast kmax, k = use->fast_outs(kmax); k < kmax; k++) {
 787           Node* u = use->fast_out(k);
 788           if (u->is_InlineType()) {
 789             // Use in flat field can be eliminated
 790             InlineTypeNode* vt = u->as_InlineType();
 791             for (uint i = 0; i < vt->field_count(); ++i) {
 792               if (vt->field_value(i) == use && !vt->field_is_flat(i)) {
 793                 can_eliminate = false; // Use in non-flat field
 794                 break;
 795               }
 796             }
 797           } else {
 798             // Add other uses to the worklist to process individually
 799             worklist.push(use);
 800           }
 801         }
 802       } else if (use->Opcode() == Op_StoreX && use->in(MemNode::Address) == res) {
 803         // Store to mark word of inline type larval buffer
 804         assert(res_type->is_inlinetypeptr(), "Unexpected store to mark word");
 805       } else if (res_type->is_inlinetypeptr() && (use->Opcode() == Op_MemBarRelease || use->Opcode() == Op_MemBarStoreStore)) {
 806         // Inline type buffer allocations are followed by a membar
 807       } else if (reduce_merge_precheck &&
 808                  (use->is_Phi() || use->is_EncodeP() ||
 809                   use->Opcode() == Op_MemBarRelease ||
 810                   (UseStoreStoreForCtor && use->Opcode() == Op_MemBarStoreStore))) {
 811         // Nothing to do
 812       } else if (use->Opcode() != Op_CastP2X) { // CastP2X is used by card mark
 813         if (use->is_Phi()) {
 814           if (use->outcnt() == 1 && use->unique_out()->Opcode() == Op_Return) {
 815             NOT_PRODUCT(fail_eliminate = "Object is return value";)
 816           } else {
 817             NOT_PRODUCT(fail_eliminate = "Object is referenced by Phi";)
 818           }
 819           DEBUG_ONLY(disq_node = use;)
 820         } else {
 821           if (use->Opcode() == Op_Return) {
 822             NOT_PRODUCT(fail_eliminate = "Object is return value";)
 823           } else {
 824             NOT_PRODUCT(fail_eliminate = "Object is referenced by node";)
 825           }
 826           DEBUG_ONLY(disq_node = use;)
 827         }
 828         can_eliminate = false;
 829       } else {
 830         assert(use->Opcode() == Op_CastP2X, "should be");
 831         assert(!use->has_out_with(Op_OrL), "should have been removed because oop is never null");
 832       }
 833     }
 834   }
 835 
 836 #ifndef PRODUCT
 837   if (PrintEliminateAllocations && safepoints != nullptr) {
 838     if (can_eliminate) {
 839       tty->print("Scalar ");
 840       if (res == nullptr)
 841         alloc->dump();
 842       else
 843         res->dump();
 844     } else {
 845       tty->print("NotScalar (%s)", fail_eliminate);
 846       if (res == nullptr)
 847         alloc->dump();
 848       else
 849         res->dump();
 850 #ifdef ASSERT
 851       if (disq_node != nullptr) {
 852           tty->print("  >>>> ");
 853           disq_node->dump();
 854       }
 855 #endif /*ASSERT*/
 856     }
 857   }
 858 
 859   if (TraceReduceAllocationMerges && !can_eliminate && reduce_merge_precheck) {
 860     tty->print_cr("\tCan't eliminate allocation because '%s': ", fail_eliminate != nullptr ? fail_eliminate : "");
 861     DEBUG_ONLY(if (disq_node != nullptr) disq_node->dump();)
 862   }
 863 #endif
 864   return can_eliminate;
 865 }
 866 
 867 void PhaseMacroExpand::undo_previous_scalarizations(GrowableArray <SafePointNode *> safepoints_done, AllocateNode* alloc) {
 868   Node* res = alloc->result_cast();
 869   int nfields = 0;
 870   assert(res == nullptr || res->is_CheckCastPP(), "unexpected AllocateNode result");
 871 
 872   if (res != nullptr) {
 873     const TypeOopPtr* res_type = _igvn.type(res)->isa_oopptr();
 874 
 875     if (res_type->isa_instptr()) {
 876       // find the fields of the class which will be needed for safepoint debug information
 877       ciInstanceKlass* iklass = res_type->is_instptr()->instance_klass();
 878       nfields = iklass->nof_nonstatic_fields();
 879     } else {
 880       // find the array's elements which will be needed for safepoint debug information
 881       nfields = alloc->in(AllocateNode::ALength)->find_int_con(-1);
 882       assert(nfields >= 0, "must be an array klass.");
 883     }
 884   }
 885 
 886   // rollback processed safepoints
 887   while (safepoints_done.length() > 0) {
 888     SafePointNode* sfpt_done = safepoints_done.pop();
 889     // remove any extra entries we added to the safepoint
 890     uint last = sfpt_done->req() - 1;
 891     for (int k = 0;  k < nfields; k++) {
 892       sfpt_done->del_req(last--);
 893     }
 894     JVMState *jvms = sfpt_done->jvms();
 895     jvms->set_endoff(sfpt_done->req());
 896     // Now make a pass over the debug information replacing any references
 897     // to SafePointScalarObjectNode with the allocated object.
 898     int start = jvms->debug_start();
 899     int end   = jvms->debug_end();
 900     for (int i = start; i < end; i++) {
 901       if (sfpt_done->in(i)->is_SafePointScalarObject()) {
 902         SafePointScalarObjectNode* scobj = sfpt_done->in(i)->as_SafePointScalarObject();
 903         if (scobj->first_index(jvms) == sfpt_done->req() &&
 904             scobj->n_fields() == (uint)nfields) {
 905           assert(scobj->alloc() == alloc, "sanity");
 906           sfpt_done->set_req(i, res);
 907         }
 908       }
 909     }
 910     _igvn._worklist.push(sfpt_done);
 911   }
 912 }
 913 
 914 #ifdef ASSERT
 915   // Verify if a value can be written into a field.
 916   void verify_type_compatability(const Type* value_type, const Type* field_type) {
 917     BasicType value_bt = value_type->basic_type();
 918     BasicType field_bt = field_type->basic_type();
 919 
 920     // Primitive types must match.
 921     if (is_java_primitive(value_bt) && value_bt == field_bt) { return; }
 922 
 923     // I have been struggling to make a similar assert for non-primitive
 924     // types. I we can add one in the future. For now, I just let them
 925     // pass without checks.
 926     // In particular, I was struggling with a value that came from a call,
 927     // and had only a non-null check CastPP. There was also a checkcast
 928     // in the graph to verify the interface, but the corresponding
 929     // CheckCastPP result was not updated in the stack slot, and so
 930     // we ended up using the CastPP. That means that the field knows
 931     // that it should get an oop from an interface, but the value lost
 932     // that information, and so it is not a subtype.
 933     // There may be other issues, feel free to investigate further!
 934     if (!is_java_primitive(value_bt)) { return; }
 935 
 936     tty->print_cr("value not compatible for field: %s vs %s",
 937                   type2name(value_bt),
 938                   type2name(field_bt));
 939     tty->print("value_type: ");
 940     value_type->dump();
 941     tty->cr();
 942     tty->print("field_type: ");
 943     field_type->dump();
 944     tty->cr();
 945     assert(false, "value_type does not fit field_type");
 946   }
 947 #endif
 948 
 949 void PhaseMacroExpand::process_field_value_at_safepoint(const Type* field_type, Node* field_val, SafePointNode* sfpt, Unique_Node_List* value_worklist) {
 950   if (UseCompressedOops && field_type->isa_narrowoop()) {
 951     // Enable "DecodeN(EncodeP(Allocate)) --> Allocate" transformation
 952     // to be able scalar replace the allocation.
 953     if (field_val->is_EncodeP()) {
 954       field_val = field_val->in(1);
 955     } else if (!field_val->is_InlineType()) {
 956       field_val = transform_later(new DecodeNNode(field_val, field_val->get_ptr_type()));
 957     }
 958   }
 959 
 960   // Keep track of inline types to scalarize them later
 961   if (field_val->is_InlineType()) {
 962     value_worklist->push(field_val);
 963   } else if (field_val->is_Phi()) {
 964     PhiNode* phi = field_val->as_Phi();
 965     // Eagerly replace inline type phis now since we could be removing an inline type allocation where we must
 966     // scalarize all its fields in safepoints.
 967     field_val = phi->try_push_inline_types_down(&_igvn, true);
 968     if (field_val->is_InlineType()) {
 969       value_worklist->push(field_val);
 970     }
 971   }
 972   DEBUG_ONLY(verify_type_compatability(field_val->bottom_type(), field_type);)
 973   sfpt->add_req(field_val);
 974 }
 975 
 976 bool PhaseMacroExpand::add_array_elems_to_safepoint(AllocateNode* alloc, const TypeAryPtr* array_type, SafePointNode* sfpt, Unique_Node_List* value_worklist) {
 977   const Type* elem_type = array_type->elem();
 978   BasicType basic_elem_type = elem_type->array_element_basic_type();
 979 
 980   intptr_t elem_size;
 981   uint header_size;
 982   if (array_type->is_flat()) {
 983     elem_size = array_type->flat_elem_size();
 984     header_size = arrayOopDesc::base_offset_in_bytes(T_FLAT_ELEMENT);
 985   } else {
 986     elem_size = type2aelembytes(basic_elem_type);
 987     header_size = arrayOopDesc::base_offset_in_bytes(basic_elem_type);
 988   }
 989 
 990   int n_elems = alloc->in(AllocateNode::ALength)->get_int();
 991   for (int elem_idx = 0; elem_idx < n_elems; elem_idx++) {
 992     intptr_t elem_offset = header_size + elem_idx * elem_size;
 993     const TypeAryPtr* elem_adr_type = array_type->with_offset(elem_offset);
 994     Node* elem_val;
 995     if (array_type->is_flat()) {
 996       ciInlineKlass* elem_klass = elem_type->inline_klass();
 997       assert(elem_klass->maybe_flat_in_array(), "must be flat in array");
 998       elem_val = inline_type_from_mem(elem_klass, elem_adr_type, elem_idx, 0, array_type->is_null_free(), alloc, sfpt);
 999     } else {
1000       elem_val = value_from_mem(sfpt->memory(), sfpt->control(), basic_elem_type, elem_type, elem_adr_type, alloc);
1001 #ifndef PRODUCT
1002       if (PrintEliminateAllocations && elem_val == nullptr) {
1003         tty->print("=== At SafePoint node %d can't find value of array element [%d]", sfpt->_idx, elem_idx);
1004         tty->print(", which prevents elimination of: ");
1005         alloc->dump();
1006       }
1007 #endif // PRODUCT
1008     }
1009     if (elem_val == nullptr) {
1010       return false;
1011     }
1012 
1013     process_field_value_at_safepoint(elem_type, elem_val, sfpt, value_worklist);
1014   }
1015 
1016   return true;
1017 }
1018 
1019 // Recursively adds all flattened fields of a type 'iklass' inside 'base' to 'sfpt'.
1020 // 'offset_minus_header' refers to the offset of the payload of 'iklass' inside 'base' minus the
1021 // payload offset of 'iklass'. If 'base' is of type 'iklass' then 'offset_minus_header' == 0.
1022 bool PhaseMacroExpand::add_inst_fields_to_safepoint(ciInstanceKlass* iklass, AllocateNode* alloc, Node* base, int offset_minus_header, SafePointNode* sfpt, Unique_Node_List* value_worklist) {
1023   const TypeInstPtr* base_type = _igvn.type(base)->is_instptr();
1024   auto report_failure = [&](int offset) {
1025 #ifndef PRODUCT
1026     if (PrintEliminateAllocations) {
1027       ciInstanceKlass* base_klass = base_type->instance_klass();
1028       ciField* flattened_field = base_klass->get_field_by_offset(offset, false);
1029       assert(flattened_field != nullptr, "must have a field of type %s at offset %d", base_klass->name()->as_utf8(), offset);
1030       tty->print("=== At SafePoint node %d can't find value of field: ", sfpt->_idx);
1031       flattened_field->print();
1032       int field_idx = C->alias_type(flattened_field)->index();
1033       tty->print(" (alias_idx=%d)", field_idx);
1034       tty->print(", which prevents elimination of: ");
1035       base->dump();
1036     }
1037 #endif // PRODUCT
1038   };
1039 
1040   for (int i = 0; i < iklass->nof_declared_nonstatic_fields(); i++) {
1041     ciField* field = iklass->declared_nonstatic_field_at(i);
1042     if (field->is_flat()) {
1043       ciInlineKlass* fvk = field->type()->as_inline_klass();
1044       int field_offset_minus_header = offset_minus_header + field->offset_in_bytes() - fvk->payload_offset();
1045       bool success = add_inst_fields_to_safepoint(fvk, alloc, base, field_offset_minus_header, sfpt, value_worklist);
1046       if (!success) {
1047         return false;
1048       }
1049 
1050       // The null marker of a field is added right after we scalarize that field
1051       if (!field->is_null_free()) {
1052         int nm_offset = offset_minus_header + field->null_marker_offset();
1053         Node* null_marker = value_from_mem(sfpt->memory(), sfpt->control(), T_BOOLEAN, TypeInt::BOOL, base_type->with_offset(nm_offset), alloc);
1054         if (null_marker == nullptr) {
1055           report_failure(nm_offset);
1056           return false;
1057         }
1058         process_field_value_at_safepoint(TypeInt::BOOL, null_marker, sfpt, value_worklist);
1059       }
1060 
1061       continue;
1062     }
1063 
1064     int offset = offset_minus_header + field->offset_in_bytes();
1065     ciType* elem_type = field->type();
1066     BasicType basic_elem_type = field->layout_type();
1067 
1068     const Type* field_type;
1069     if (is_reference_type(basic_elem_type)) {
1070       if (!elem_type->is_loaded()) {
1071         field_type = TypeInstPtr::BOTTOM;
1072       } else {
1073         field_type = TypeOopPtr::make_from_klass(elem_type->as_klass());
1074       }
1075       if (UseCompressedOops) {
1076         field_type = field_type->make_narrowoop();
1077         basic_elem_type = T_NARROWOOP;
1078       }
1079     } else {
1080       field_type = Type::get_const_basic_type(basic_elem_type);
1081     }
1082 
1083     const TypeInstPtr* field_addr_type = base_type->add_offset(offset)->isa_instptr();
1084     Node* field_val = value_from_mem(sfpt->memory(), sfpt->control(), basic_elem_type, field_type, field_addr_type, alloc);
1085     if (field_val == nullptr) {
1086       report_failure(offset);
1087       return false;
1088     }
1089     process_field_value_at_safepoint(field_type, field_val, sfpt, value_worklist);
1090   }
1091 
1092   return true;
1093 }
1094 
1095 SafePointScalarObjectNode* PhaseMacroExpand::create_scalarized_object_description(AllocateNode* alloc, SafePointNode* sfpt,
1096                                                                                   Unique_Node_List* value_worklist) {
1097   // Fields of scalar objs are referenced only at the end
1098   // of regular debuginfo at the last (youngest) JVMS.
1099   // Record relative start index.
1100   ciInstanceKlass* iklass    = nullptr;
1101   const TypeOopPtr* res_type = nullptr;
1102   int nfields                = 0;
1103   uint first_ind             = (sfpt->req() - sfpt->jvms()->scloff());
1104   Node* res                  = alloc->result_cast();
1105 
1106   assert(res == nullptr || res->is_CheckCastPP(), "unexpected AllocateNode result");
1107   assert(sfpt->jvms() != nullptr, "missed JVMS");
1108   uint before_sfpt_req = sfpt->req();
1109 
1110   if (res != nullptr) { // Could be null when there are no users
1111     res_type = _igvn.type(res)->isa_oopptr();
1112 
1113     if (res_type->isa_instptr()) {
1114       // find the fields of the class which will be needed for safepoint debug information
1115       iklass = res_type->is_instptr()->instance_klass();
1116       nfields = iklass->nof_nonstatic_fields();
1117     } else {
1118       // find the array's elements which will be needed for safepoint debug information
1119       nfields = alloc->in(AllocateNode::ALength)->find_int_con(-1);
1120       assert(nfields >= 0, "must be an array klass.");
1121     }
1122 
1123     if (res->bottom_type()->is_inlinetypeptr()) {
1124       // Nullable inline types have a null marker field which is added to the safepoint when scalarizing them (see
1125       // InlineTypeNode::make_scalar_in_safepoint()). When having circular inline types, we stop scalarizing at depth 1
1126       // to avoid an endless recursion. Therefore, we do not have a SafePointScalarObjectNode node here, yet.
1127       // We are about to create a SafePointScalarObjectNode as if this is a normal object. Add an additional int input
1128       // with value 1 which sets the null marker to true to indicate that the object is always non-null. This input is checked
1129       // later in PhaseOutput::filLocArray() for inline types.
1130       sfpt->add_req(_igvn.intcon(1));
1131     }
1132   }
1133 
1134   SafePointScalarObjectNode* sobj = new SafePointScalarObjectNode(res_type, alloc, first_ind, sfpt->jvms()->depth(), nfields);
1135   sobj->init_req(0, C->root());
1136   transform_later(sobj);
1137 
1138   if (res == nullptr) {
1139     sfpt->jvms()->set_endoff(sfpt->req());
1140     return sobj;
1141   }
1142 
1143   bool success;
1144   if (iklass == nullptr) {
1145     success = add_array_elems_to_safepoint(alloc, res_type->is_aryptr(), sfpt, value_worklist);
1146   } else {
1147     success = add_inst_fields_to_safepoint(iklass, alloc, res, 0, sfpt, value_worklist);
1148   }
1149 
1150   // We weren't able to find a value for this field, remove all the fields added to the safepoint
1151   if (!success) {
1152     for (uint i = sfpt->req() - 1; i >= before_sfpt_req; i--) {
1153       sfpt->del_req(i);
1154     }
1155     _igvn._worklist.push(sfpt);
1156     return nullptr;
1157   }
1158 
1159   sfpt->jvms()->set_endoff(sfpt->req());
1160   return sobj;
1161 }
1162 
1163 // Do scalar replacement.
1164 bool PhaseMacroExpand::scalar_replacement(AllocateNode *alloc, GrowableArray <SafePointNode *>& safepoints) {
1165   GrowableArray <SafePointNode *> safepoints_done;
1166   Node* res = alloc->result_cast();
1167   assert(res == nullptr || res->is_CheckCastPP(), "unexpected AllocateNode result");
1168   const TypeOopPtr* res_type = nullptr;
1169   if (res != nullptr) { // Could be null when there are no users
1170     res_type = _igvn.type(res)->isa_oopptr();
1171   }
1172 
1173   // Process the safepoint uses
1174   Unique_Node_List value_worklist;
1175   while (safepoints.length() > 0) {
1176     SafePointNode* sfpt = safepoints.pop();
1177     SafePointScalarObjectNode* sobj = create_scalarized_object_description(alloc, sfpt, &value_worklist);
1178 
1179     if (sobj == nullptr) {
1180       undo_previous_scalarizations(safepoints_done, alloc);
1181       return false;
1182     }
1183 
1184     // Now make a pass over the debug information replacing any references
1185     // to the allocated object with "sobj"
1186     JVMState *jvms = sfpt->jvms();
1187     sfpt->replace_edges_in_range(res, sobj, jvms->debug_start(), jvms->debug_end(), &_igvn);
1188     _igvn._worklist.push(sfpt);
1189 
1190     // keep it for rollback
1191     safepoints_done.append_if_missing(sfpt);
1192   }
1193   // Scalarize inline types that were added to the safepoint.
1194   // Don't allow linking a constant oop (if available) for flat array elements
1195   // because Deoptimization::reassign_flat_array_elements needs field values.
1196   bool allow_oop = (res_type != nullptr) && !res_type->is_flat();
1197   for (uint i = 0; i < value_worklist.size(); ++i) {
1198     InlineTypeNode* vt = value_worklist.at(i)->as_InlineType();
1199     vt->make_scalar_in_safepoints(&_igvn, allow_oop);
1200   }
1201   return true;
1202 }
1203 
1204 static void disconnect_projections(MultiNode* n, PhaseIterGVN& igvn) {
1205   Node* ctl_proj = n->proj_out_or_null(TypeFunc::Control);
1206   Node* mem_proj = n->proj_out_or_null(TypeFunc::Memory);
1207   if (ctl_proj != nullptr) {
1208     igvn.replace_node(ctl_proj, n->in(0));
1209   }
1210   if (mem_proj != nullptr) {
1211     igvn.replace_node(mem_proj, n->in(TypeFunc::Memory));
1212   }
1213 }
1214 
1215 // Process users of eliminated allocation.
1216 void PhaseMacroExpand::process_users_of_allocation(CallNode *alloc, bool inline_alloc) {
1217   Unique_Node_List worklist;
1218   Node* res = alloc->result_cast();
1219   if (res != nullptr) {
1220     worklist.push(res);
1221   }
1222   while (worklist.size() > 0) {
1223     res = worklist.pop();
1224     for (DUIterator_Last jmin, j = res->last_outs(jmin); j >= jmin; ) {
1225       Node *use = res->last_out(j);
1226       uint oc1 = res->outcnt();
1227 
1228       if (use->is_AddP()) {
1229         for (DUIterator_Last kmin, k = use->last_outs(kmin); k >= kmin; ) {
1230           Node *n = use->last_out(k);
1231           uint oc2 = use->outcnt();
1232           if (n->is_Store()) {
1233             for (DUIterator_Fast pmax, p = n->fast_outs(pmax); p < pmax; p++) {
1234               MemBarNode* mb = n->fast_out(p)->isa_MemBar();
1235               if (mb != nullptr && mb->req() <= MemBarNode::Precedent && mb->in(MemBarNode::Precedent) == n) {
1236                 // MemBarVolatiles should have been removed by MemBarNode::Ideal() for non-inline allocations
1237                 assert(inline_alloc, "MemBarVolatile should be eliminated for non-escaping object");
1238                 mb->remove(&_igvn);
1239               }
1240             }
1241             _igvn.replace_node(n, n->in(MemNode::Memory));
1242           } else {
1243             eliminate_gc_barrier(n);
1244           }
1245           k -= (oc2 - use->outcnt());
1246         }
1247         _igvn.remove_dead_node(use);
1248       } else if (use->is_ArrayCopy()) {
1249         // Disconnect ArrayCopy node
1250         ArrayCopyNode* ac = use->as_ArrayCopy();
1251         if (ac->is_clonebasic()) {
1252           Node* membar_after = ac->proj_out(TypeFunc::Control)->unique_ctrl_out();
1253           disconnect_projections(ac, _igvn);
1254           assert(alloc->in(TypeFunc::Memory)->is_Proj() && alloc->in(TypeFunc::Memory)->in(0)->Opcode() == Op_MemBarCPUOrder, "mem barrier expected before allocation");
1255           Node* membar_before = alloc->in(TypeFunc::Memory)->in(0);
1256           disconnect_projections(membar_before->as_MemBar(), _igvn);
1257           if (membar_after->is_MemBar()) {
1258             disconnect_projections(membar_after->as_MemBar(), _igvn);
1259           }
1260         } else {
1261           assert(ac->is_arraycopy_validated() ||
1262                  ac->is_copyof_validated() ||
1263                  ac->is_copyofrange_validated(), "unsupported");
1264           CallProjections* callprojs = ac->extract_projections(true);
1265 
1266           _igvn.replace_node(callprojs->fallthrough_ioproj, ac->in(TypeFunc::I_O));
1267           _igvn.replace_node(callprojs->fallthrough_memproj, ac->in(TypeFunc::Memory));
1268           _igvn.replace_node(callprojs->fallthrough_catchproj, ac->in(TypeFunc::Control));
1269 
1270           // Set control to top. IGVN will remove the remaining projections
1271           ac->set_req(0, top());
1272           ac->replace_edge(res, top(), &_igvn);
1273 
1274           // Disconnect src right away: it can help find new
1275           // opportunities for allocation elimination
1276           Node* src = ac->in(ArrayCopyNode::Src);
1277           ac->replace_edge(src, top(), &_igvn);
1278           // src can be top at this point if src and dest of the
1279           // arraycopy were the same
1280           if (src->outcnt() == 0 && !src->is_top()) {
1281             _igvn.remove_dead_node(src);
1282           }
1283         }
1284         _igvn._worklist.push(ac);
1285       } else if (use->is_InlineType()) {
1286         assert(use->as_InlineType()->get_oop() == res, "unexpected inline type ptr use");
1287         // Cut off oop input and remove known instance id from type
1288         _igvn.rehash_node_delayed(use);
1289         use->as_InlineType()->set_oop(_igvn, _igvn.zerocon(T_OBJECT));
1290         use->as_InlineType()->set_is_buffered(_igvn, false);
1291         const TypeOopPtr* toop = _igvn.type(use)->is_oopptr()->cast_to_instance_id(TypeOopPtr::InstanceBot);
1292         _igvn.set_type(use, toop);
1293         use->as_InlineType()->set_type(toop);
1294         // Process users
1295         for (DUIterator_Fast kmax, k = use->fast_outs(kmax); k < kmax; k++) {
1296           Node* u = use->fast_out(k);
1297           if (!u->is_InlineType() && !u->is_StoreFlat()) {
1298             worklist.push(u);
1299           }
1300         }
1301       } else if (use->Opcode() == Op_StoreX && use->in(MemNode::Address) == res) {
1302         // Store to mark word of inline type larval buffer
1303         assert(inline_alloc, "Unexpected store to mark word");
1304         _igvn.replace_node(use, use->in(MemNode::Memory));
1305       } else if (use->Opcode() == Op_MemBarRelease || use->Opcode() == Op_MemBarStoreStore) {
1306         // Inline type buffer allocations are followed by a membar
1307         assert(inline_alloc, "Unexpected MemBarRelease");
1308         use->as_MemBar()->remove(&_igvn);
1309       } else {
1310         eliminate_gc_barrier(use);
1311       }
1312       j -= (oc1 - res->outcnt());
1313     }
1314     assert(res->outcnt() == 0, "all uses of allocated objects must be deleted");
1315     _igvn.remove_dead_node(res);
1316   }
1317 
1318   //
1319   // Process other users of allocation's projections
1320   //
1321   if (_callprojs->resproj[0] != nullptr && _callprojs->resproj[0]->outcnt() != 0) {
1322     // First disconnect stores captured by Initialize node.
1323     // If Initialize node is eliminated first in the following code,
1324     // it will kill such stores and DUIterator_Last will assert.
1325     for (DUIterator_Fast jmax, j = _callprojs->resproj[0]->fast_outs(jmax);  j < jmax; j++) {
1326       Node* use = _callprojs->resproj[0]->fast_out(j);
1327       if (use->is_AddP()) {
1328         // raw memory addresses used only by the initialization
1329         _igvn.replace_node(use, C->top());
1330         --j; --jmax;
1331       }
1332     }
1333     for (DUIterator_Last jmin, j = _callprojs->resproj[0]->last_outs(jmin); j >= jmin; ) {
1334       Node* use = _callprojs->resproj[0]->last_out(j);
1335       uint oc1 = _callprojs->resproj[0]->outcnt();
1336       if (use->is_Initialize()) {
1337         // Eliminate Initialize node.
1338         InitializeNode *init = use->as_Initialize();
1339         Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
1340         if (ctrl_proj != nullptr) {
1341           _igvn.replace_node(ctrl_proj, init->in(TypeFunc::Control));
1342 #ifdef ASSERT
1343           // If the InitializeNode has no memory out, it will die, and tmp will become null
1344           Node* tmp = init->in(TypeFunc::Control);
1345           assert(tmp == nullptr || tmp == _callprojs->fallthrough_catchproj, "allocation control projection");
1346 #endif
1347         }
1348         Node* mem = init->in(TypeFunc::Memory);
1349 #ifdef ASSERT
1350         if (init->number_of_projs(TypeFunc::Memory) > 0) {
1351           if (mem->is_MergeMem()) {
1352             assert(mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw) == _callprojs->fallthrough_memproj, "allocation memory projection");
1353           } else {
1354             assert(mem == _callprojs->fallthrough_memproj, "allocation memory projection");
1355           }
1356         }
1357 #endif
1358         init->replace_mem_projs_by(mem, &_igvn);
1359         assert(init->outcnt() == 0, "should only have had a control and some memory projections, and we removed them");
1360       } else if (use->Opcode() == Op_MemBarStoreStore) {
1361         // Inline type buffer allocations are followed by a membar
1362         assert(inline_alloc, "Unexpected MemBarStoreStore");
1363         use->as_MemBar()->remove(&_igvn);
1364       } else  {
1365         assert(false, "only Initialize or AddP expected");
1366       }
1367       j -= (oc1 - _callprojs->resproj[0]->outcnt());
1368     }
1369   }
1370   if (_callprojs->fallthrough_catchproj != nullptr) {
1371     _igvn.replace_node(_callprojs->fallthrough_catchproj, alloc->in(TypeFunc::Control));
1372   }
1373   if (_callprojs->fallthrough_memproj != nullptr) {
1374     _igvn.replace_node(_callprojs->fallthrough_memproj, alloc->in(TypeFunc::Memory));
1375   }
1376   if (_callprojs->catchall_memproj != nullptr) {
1377     _igvn.replace_node(_callprojs->catchall_memproj, C->top());
1378   }
1379   if (_callprojs->fallthrough_ioproj != nullptr) {
1380     _igvn.replace_node(_callprojs->fallthrough_ioproj, alloc->in(TypeFunc::I_O));
1381   }
1382   if (_callprojs->catchall_ioproj != nullptr) {
1383     _igvn.replace_node(_callprojs->catchall_ioproj, C->top());
1384   }
1385   if (_callprojs->catchall_catchproj != nullptr) {
1386     _igvn.replace_node(_callprojs->catchall_catchproj, C->top());
1387   }
1388 }
1389 
1390 bool PhaseMacroExpand::eliminate_allocate_node(AllocateNode *alloc) {
1391   // If reallocation fails during deoptimization we'll pop all
1392   // interpreter frames for this compiled frame and that won't play
1393   // nice with JVMTI popframe.
1394   // We avoid this issue by eager reallocation when the popframe request
1395   // is received.
1396   if (!EliminateAllocations) {
1397     return false;
1398   }
1399   Node* klass = alloc->in(AllocateNode::KlassNode);
1400   const TypeKlassPtr* tklass = _igvn.type(klass)->is_klassptr();
1401 
1402   // Attempt to eliminate inline type buffer allocations
1403   // regardless of usage and escape/replaceable status.
1404   bool inline_alloc = tklass->isa_instklassptr() &&
1405                       tklass->is_instklassptr()->instance_klass()->is_inlinetype();
1406   if (!alloc->_is_non_escaping && !inline_alloc) {
1407     return false;
1408   }
1409   // Eliminate boxing allocations which are not used
1410   // regardless scalar replaceable status.
1411   Node* res = alloc->result_cast();
1412   bool boxing_alloc = (res == nullptr) && C->eliminate_boxing() &&
1413                       tklass->isa_instklassptr() &&
1414                       tklass->is_instklassptr()->instance_klass()->is_box_klass();
1415   if (!alloc->_is_scalar_replaceable && !boxing_alloc && !inline_alloc) {
1416     return false;
1417   }
1418 
1419   _callprojs = alloc->extract_projections(false /*separate_io_proj*/, false /*do_asserts*/);
1420 
1421   GrowableArray <SafePointNode *> safepoints;
1422   if (!can_eliminate_allocation(&_igvn, alloc, &safepoints)) {
1423     return false;
1424   }
1425 
1426   if (!alloc->_is_scalar_replaceable) {
1427     assert(res == nullptr || inline_alloc, "sanity");
1428     // We can only eliminate allocation if all debug info references
1429     // are already replaced with SafePointScalarObject because
1430     // we can't search for a fields value without instance_id.
1431     if (safepoints.length() > 0) {
1432       return false;
1433     }
1434   }
1435 
1436   if (!scalar_replacement(alloc, safepoints)) {
1437     return false;
1438   }
1439 
1440   CompileLog* log = C->log();
1441   if (log != nullptr) {
1442     log->head("eliminate_allocation type='%d'",
1443               log->identify(tklass->exact_klass()));
1444     JVMState* p = alloc->jvms();
1445     while (p != nullptr) {
1446       log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
1447       p = p->caller();
1448     }
1449     log->tail("eliminate_allocation");
1450   }
1451 
1452   process_users_of_allocation(alloc, inline_alloc);
1453 
1454 #ifndef PRODUCT
1455   if (PrintEliminateAllocations) {
1456     if (alloc->is_AllocateArray())
1457       tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
1458     else
1459       tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
1460   }
1461 #endif
1462 
1463   return true;
1464 }
1465 
1466 bool PhaseMacroExpand::eliminate_boxing_node(CallStaticJavaNode *boxing) {
1467   // EA should remove all uses of non-escaping boxing node.
1468   if (!C->eliminate_boxing() || boxing->proj_out_or_null(TypeFunc::Parms) != nullptr) {
1469     return false;
1470   }
1471 
1472   assert(boxing->result_cast() == nullptr, "unexpected boxing node result");
1473 
1474   _callprojs = boxing->extract_projections(false /*separate_io_proj*/, false /*do_asserts*/);
1475 
1476   const TypeTuple* r = boxing->tf()->range_sig();
1477   assert(r->cnt() > TypeFunc::Parms, "sanity");
1478   const TypeInstPtr* t = r->field_at(TypeFunc::Parms)->isa_instptr();
1479   assert(t != nullptr, "sanity");
1480 
1481   CompileLog* log = C->log();
1482   if (log != nullptr) {
1483     log->head("eliminate_boxing type='%d'",
1484               log->identify(t->instance_klass()));
1485     JVMState* p = boxing->jvms();
1486     while (p != nullptr) {
1487       log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
1488       p = p->caller();
1489     }
1490     log->tail("eliminate_boxing");
1491   }
1492 
1493   process_users_of_allocation(boxing);
1494 
1495 #ifndef PRODUCT
1496   if (PrintEliminateAllocations) {
1497     tty->print("++++ Eliminated: %d ", boxing->_idx);
1498     boxing->method()->print_short_name(tty);
1499     tty->cr();
1500   }
1501 #endif
1502 
1503   return true;
1504 }
1505 
1506 
1507 Node* PhaseMacroExpand::make_load(Node* ctl, Node* mem, Node* base, int offset, const Type* value_type, BasicType bt) {
1508   Node* adr = basic_plus_adr(base, offset);
1509   const TypePtr* adr_type = adr->bottom_type()->is_ptr();
1510   Node* value = LoadNode::make(_igvn, ctl, mem, adr, adr_type, value_type, bt, MemNode::unordered);
1511   transform_later(value);
1512   return value;
1513 }
1514 
1515 
1516 Node* PhaseMacroExpand::make_store(Node* ctl, Node* mem, Node* base, int offset, Node* value, BasicType bt) {
1517   Node* adr = basic_plus_adr(base, offset);
1518   mem = StoreNode::make(_igvn, ctl, mem, adr, nullptr, value, bt, MemNode::unordered);
1519   transform_later(mem);
1520   return mem;
1521 }
1522 
1523 //=============================================================================
1524 //
1525 //                              A L L O C A T I O N
1526 //
1527 // Allocation attempts to be fast in the case of frequent small objects.
1528 // It breaks down like this:
1529 //
1530 // 1) Size in doublewords is computed.  This is a constant for objects and
1531 // variable for most arrays.  Doubleword units are used to avoid size
1532 // overflow of huge doubleword arrays.  We need doublewords in the end for
1533 // rounding.
1534 //
1535 // 2) Size is checked for being 'too large'.  Too-large allocations will go
1536 // the slow path into the VM.  The slow path can throw any required
1537 // exceptions, and does all the special checks for very large arrays.  The
1538 // size test can constant-fold away for objects.  For objects with
1539 // finalizers it constant-folds the otherway: you always go slow with
1540 // finalizers.
1541 //
1542 // 3) If NOT using TLABs, this is the contended loop-back point.
1543 // Load-Locked the heap top.  If using TLABs normal-load the heap top.
1544 //
1545 // 4) Check that heap top + size*8 < max.  If we fail go the slow ` route.
1546 // NOTE: "top+size*8" cannot wrap the 4Gig line!  Here's why: for largish
1547 // "size*8" we always enter the VM, where "largish" is a constant picked small
1548 // enough that there's always space between the eden max and 4Gig (old space is
1549 // there so it's quite large) and large enough that the cost of entering the VM
1550 // is dwarfed by the cost to initialize the space.
1551 //
1552 // 5) If NOT using TLABs, Store-Conditional the adjusted heap top back
1553 // down.  If contended, repeat at step 3.  If using TLABs normal-store
1554 // adjusted heap top back down; there is no contention.
1555 //
1556 // 6) If !ZeroTLAB then Bulk-clear the object/array.  Fill in klass & mark
1557 // fields.
1558 //
1559 // 7) Merge with the slow-path; cast the raw memory pointer to the correct
1560 // oop flavor.
1561 //
1562 //=============================================================================
1563 // FastAllocateSizeLimit value is in DOUBLEWORDS.
1564 // Allocations bigger than this always go the slow route.
1565 // This value must be small enough that allocation attempts that need to
1566 // trigger exceptions go the slow route.  Also, it must be small enough so
1567 // that heap_top + size_in_bytes does not wrap around the 4Gig limit.
1568 //=============================================================================j//
1569 // %%% Here is an old comment from parseHelper.cpp; is it outdated?
1570 // The allocator will coalesce int->oop copies away.  See comment in
1571 // coalesce.cpp about how this works.  It depends critically on the exact
1572 // code shape produced here, so if you are changing this code shape
1573 // make sure the GC info for the heap-top is correct in and around the
1574 // slow-path call.
1575 //
1576 
1577 void PhaseMacroExpand::expand_allocate_common(
1578             AllocateNode* alloc, // allocation node to be expanded
1579             Node* length,  // array length for an array allocation
1580             Node* init_val, // value to initialize the array with
1581             const TypeFunc* slow_call_type, // Type of slow call
1582             address slow_call_address,  // Address of slow call
1583             Node* valid_length_test // whether length is valid or not
1584     )
1585 {
1586   Node* ctrl = alloc->in(TypeFunc::Control);
1587   Node* mem  = alloc->in(TypeFunc::Memory);
1588   Node* i_o  = alloc->in(TypeFunc::I_O);
1589   Node* size_in_bytes     = alloc->in(AllocateNode::AllocSize);
1590   Node* klass_node        = alloc->in(AllocateNode::KlassNode);
1591   Node* initial_slow_test = alloc->in(AllocateNode::InitialTest);
1592   assert(ctrl != nullptr, "must have control");
1593 
1594   // We need a Region and corresponding Phi's to merge the slow-path and fast-path results.
1595   // they will not be used if "always_slow" is set
1596   enum { slow_result_path = 1, fast_result_path = 2 };
1597   Node *result_region = nullptr;
1598   Node *result_phi_rawmem = nullptr;
1599   Node *result_phi_rawoop = nullptr;
1600   Node *result_phi_i_o = nullptr;
1601 
1602   // The initial slow comparison is a size check, the comparison
1603   // we want to do is a BoolTest::gt
1604   bool expand_fast_path = true;
1605   int tv = _igvn.find_int_con(initial_slow_test, -1);
1606   if (tv >= 0) {
1607     // InitialTest has constant result
1608     //   0 - can fit in TLAB
1609     //   1 - always too big or negative
1610     assert(tv <= 1, "0 or 1 if a constant");
1611     expand_fast_path = (tv == 0);
1612     initial_slow_test = nullptr;
1613   } else {
1614     initial_slow_test = BoolNode::make_predicate(initial_slow_test, &_igvn);
1615   }
1616 
1617   if (!UseTLAB) {
1618     // Force slow-path allocation
1619     expand_fast_path = false;
1620     initial_slow_test = nullptr;
1621   }
1622 
1623   bool allocation_has_use = (alloc->result_cast() != nullptr);
1624   if (!allocation_has_use) {
1625     InitializeNode* init = alloc->initialization();
1626     if (init != nullptr) {
1627       init->remove(&_igvn);
1628     }
1629     if (expand_fast_path && (initial_slow_test == nullptr)) {
1630       // Remove allocation node and return.
1631       // Size is a non-negative constant -> no initial check needed -> directly to fast path.
1632       // Also, no usages -> empty fast path -> no fall out to slow path -> nothing left.
1633 #ifndef PRODUCT
1634       if (PrintEliminateAllocations) {
1635         tty->print("NotUsed ");
1636         Node* res = alloc->proj_out_or_null(TypeFunc::Parms);
1637         if (res != nullptr) {
1638           res->dump();
1639         } else {
1640           alloc->dump();
1641         }
1642       }
1643 #endif
1644       yank_alloc_node(alloc);
1645       return;
1646     }
1647   }
1648 
1649   enum { too_big_or_final_path = 1, need_gc_path = 2 };
1650   Node *slow_region = nullptr;
1651   Node *toobig_false = ctrl;
1652 
1653   // generate the initial test if necessary
1654   if (initial_slow_test != nullptr ) {
1655     assert (expand_fast_path, "Only need test if there is a fast path");
1656     slow_region = new RegionNode(3);
1657 
1658     // Now make the initial failure test.  Usually a too-big test but
1659     // might be a TRUE for finalizers.
1660     IfNode *toobig_iff = new IfNode(ctrl, initial_slow_test, PROB_MIN, COUNT_UNKNOWN);
1661     transform_later(toobig_iff);
1662     // Plug the failing-too-big test into the slow-path region
1663     Node* toobig_true = new IfTrueNode(toobig_iff);
1664     transform_later(toobig_true);
1665     slow_region    ->init_req( too_big_or_final_path, toobig_true );
1666     toobig_false = new IfFalseNode(toobig_iff);
1667     transform_later(toobig_false);
1668   } else {
1669     // No initial test, just fall into next case
1670     assert(allocation_has_use || !expand_fast_path, "Should already have been handled");
1671     toobig_false = ctrl;
1672     DEBUG_ONLY(slow_region = NodeSentinel);
1673   }
1674 
1675   // If we are here there are several possibilities
1676   // - expand_fast_path is false - then only a slow path is expanded. That's it.
1677   // no_initial_check means a constant allocation.
1678   // - If check always evaluates to false -> expand_fast_path is false (see above)
1679   // - If check always evaluates to true -> directly into fast path (but may bailout to slowpath)
1680   // if !allocation_has_use the fast path is empty
1681   // if !allocation_has_use && no_initial_check
1682   // - Then there are no fastpath that can fall out to slowpath -> no allocation code at all.
1683   //   removed by yank_alloc_node above.
1684 
1685   Node *slow_mem = mem;  // save the current memory state for slow path
1686   // generate the fast allocation code unless we know that the initial test will always go slow
1687   if (expand_fast_path) {
1688     // Fast path modifies only raw memory.
1689     if (mem->is_MergeMem()) {
1690       mem = mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
1691     }
1692 
1693     // allocate the Region and Phi nodes for the result
1694     result_region = new RegionNode(3);
1695     result_phi_rawmem = new PhiNode(result_region, Type::MEMORY, TypeRawPtr::BOTTOM);
1696     result_phi_i_o    = new PhiNode(result_region, Type::ABIO); // I/O is used for Prefetch
1697 
1698     // Grab regular I/O before optional prefetch may change it.
1699     // Slow-path does no I/O so just set it to the original I/O.
1700     result_phi_i_o->init_req(slow_result_path, i_o);
1701 
1702     // Name successful fast-path variables
1703     Node* fast_oop_ctrl;
1704     Node* fast_oop_rawmem;
1705 
1706     if (allocation_has_use) {
1707       Node* needgc_ctrl = nullptr;
1708       result_phi_rawoop = new PhiNode(result_region, TypeRawPtr::BOTTOM);
1709 
1710       intx prefetch_lines = length != nullptr ? AllocatePrefetchLines : AllocateInstancePrefetchLines;
1711       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1712       Node* fast_oop = bs->obj_allocate(this, mem, toobig_false, size_in_bytes, i_o, needgc_ctrl,
1713                                         fast_oop_ctrl, fast_oop_rawmem,
1714                                         prefetch_lines);
1715 
1716       if (initial_slow_test != nullptr) {
1717         // This completes all paths into the slow merge point
1718         slow_region->init_req(need_gc_path, needgc_ctrl);
1719         transform_later(slow_region);
1720       } else {
1721         // No initial slow path needed!
1722         // Just fall from the need-GC path straight into the VM call.
1723         slow_region = needgc_ctrl;
1724       }
1725 
1726       InitializeNode* init = alloc->initialization();
1727       fast_oop_rawmem = initialize_object(alloc,
1728                                           fast_oop_ctrl, fast_oop_rawmem, fast_oop,
1729                                           klass_node, length, size_in_bytes);
1730       expand_initialize_membar(alloc, init, fast_oop_ctrl, fast_oop_rawmem);
1731       expand_dtrace_alloc_probe(alloc, fast_oop, fast_oop_ctrl, fast_oop_rawmem);
1732 
1733       result_phi_rawoop->init_req(fast_result_path, fast_oop);
1734     } else {
1735       assert (initial_slow_test != nullptr, "sanity");
1736       fast_oop_ctrl   = toobig_false;
1737       fast_oop_rawmem = mem;
1738       transform_later(slow_region);
1739     }
1740 
1741     // Plug in the successful fast-path into the result merge point
1742     result_region    ->init_req(fast_result_path, fast_oop_ctrl);
1743     result_phi_i_o   ->init_req(fast_result_path, i_o);
1744     result_phi_rawmem->init_req(fast_result_path, fast_oop_rawmem);
1745   } else {
1746     slow_region = ctrl;
1747     result_phi_i_o = i_o; // Rename it to use in the following code.
1748   }
1749 
1750   // Generate slow-path call
1751   CallNode *call = new CallStaticJavaNode(slow_call_type, slow_call_address,
1752                                OptoRuntime::stub_name(slow_call_address),
1753                                TypePtr::BOTTOM);
1754   call->init_req(TypeFunc::Control,   slow_region);
1755   call->init_req(TypeFunc::I_O,       top());    // does no i/o
1756   call->init_req(TypeFunc::Memory,    slow_mem); // may gc ptrs
1757   call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
1758   call->init_req(TypeFunc::FramePtr,  alloc->in(TypeFunc::FramePtr));
1759 
1760   call->init_req(TypeFunc::Parms+0, klass_node);
1761   if (length != nullptr) {
1762     call->init_req(TypeFunc::Parms+1, length);
1763     if (init_val != nullptr) {
1764       call->init_req(TypeFunc::Parms+2, init_val);
1765     }
1766   } else {
1767     // Let the runtime know if this is a larval allocation
1768     call->init_req(TypeFunc::Parms+1, _igvn.intcon(alloc->_larval));
1769   }
1770 
1771   // Copy debug information and adjust JVMState information, then replace
1772   // allocate node with the call
1773   call->copy_call_debug_info(&_igvn, alloc);
1774   // For array allocations, copy the valid length check to the call node so Compile::final_graph_reshaping() can verify
1775   // that the call has the expected number of CatchProj nodes (in case the allocation always fails and the fallthrough
1776   // path dies).
1777   if (valid_length_test != nullptr) {
1778     call->add_req(valid_length_test);
1779   }
1780   if (expand_fast_path) {
1781     call->set_cnt(PROB_UNLIKELY_MAG(4));  // Same effect as RC_UNCOMMON.
1782   } else {
1783     // Hook i_o projection to avoid its elimination during allocation
1784     // replacement (when only a slow call is generated).
1785     call->set_req(TypeFunc::I_O, result_phi_i_o);
1786   }
1787   _igvn.replace_node(alloc, call);
1788   transform_later(call);
1789 
1790   // Identify the output projections from the allocate node and
1791   // adjust any references to them.
1792   // The control and io projections look like:
1793   //
1794   //        v---Proj(ctrl) <-----+   v---CatchProj(ctrl)
1795   //  Allocate                   Catch
1796   //        ^---Proj(io) <-------+   ^---CatchProj(io)
1797   //
1798   //  We are interested in the CatchProj nodes.
1799   //
1800   _callprojs = call->extract_projections(false /*separate_io_proj*/, false /*do_asserts*/);
1801 
1802   // An allocate node has separate memory projections for the uses on
1803   // the control and i_o paths. Replace the control memory projection with
1804   // result_phi_rawmem (unless we are only generating a slow call when
1805   // both memory projections are combined)
1806   if (expand_fast_path && _callprojs->fallthrough_memproj != nullptr) {
1807     _igvn.replace_in_uses(_callprojs->fallthrough_memproj, result_phi_rawmem);
1808   }
1809   // Now change uses of catchall_memproj to use fallthrough_memproj and delete
1810   // catchall_memproj so we end up with a call that has only 1 memory projection.
1811   if (_callprojs->catchall_memproj != nullptr) {
1812     if (_callprojs->fallthrough_memproj == nullptr) {
1813       _callprojs->fallthrough_memproj = new ProjNode(call, TypeFunc::Memory);
1814       transform_later(_callprojs->fallthrough_memproj);
1815     }
1816     _igvn.replace_in_uses(_callprojs->catchall_memproj, _callprojs->fallthrough_memproj);
1817     _igvn.remove_dead_node(_callprojs->catchall_memproj);
1818   }
1819 
1820   // An allocate node has separate i_o projections for the uses on the control
1821   // and i_o paths. Always replace the control i_o projection with result i_o
1822   // otherwise incoming i_o become dead when only a slow call is generated
1823   // (it is different from memory projections where both projections are
1824   // combined in such case).
1825   if (_callprojs->fallthrough_ioproj != nullptr) {
1826     _igvn.replace_in_uses(_callprojs->fallthrough_ioproj, result_phi_i_o);
1827   }
1828   // Now change uses of catchall_ioproj to use fallthrough_ioproj and delete
1829   // catchall_ioproj so we end up with a call that has only 1 i_o projection.
1830   if (_callprojs->catchall_ioproj != nullptr) {
1831     if (_callprojs->fallthrough_ioproj == nullptr) {
1832       _callprojs->fallthrough_ioproj = new ProjNode(call, TypeFunc::I_O);
1833       transform_later(_callprojs->fallthrough_ioproj);
1834     }
1835     _igvn.replace_in_uses(_callprojs->catchall_ioproj, _callprojs->fallthrough_ioproj);
1836     _igvn.remove_dead_node(_callprojs->catchall_ioproj);
1837   }
1838 
1839   // if we generated only a slow call, we are done
1840   if (!expand_fast_path) {
1841     // Now we can unhook i_o.
1842     if (result_phi_i_o->outcnt() > 1) {
1843       call->set_req(TypeFunc::I_O, top());
1844     } else {
1845       assert(result_phi_i_o->unique_ctrl_out() == call, "sanity");
1846       // Case of new array with negative size known during compilation.
1847       // AllocateArrayNode::Ideal() optimization disconnect unreachable
1848       // following code since call to runtime will throw exception.
1849       // As result there will be no users of i_o after the call.
1850       // Leave i_o attached to this call to avoid problems in preceding graph.
1851     }
1852     return;
1853   }
1854 
1855   if (_callprojs->fallthrough_catchproj != nullptr) {
1856     ctrl = _callprojs->fallthrough_catchproj->clone();
1857     transform_later(ctrl);
1858     _igvn.replace_node(_callprojs->fallthrough_catchproj, result_region);
1859   } else {
1860     ctrl = top();
1861   }
1862   Node *slow_result;
1863   if (_callprojs->resproj[0] == nullptr) {
1864     // no uses of the allocation result
1865     slow_result = top();
1866   } else {
1867     slow_result = _callprojs->resproj[0]->clone();
1868     transform_later(slow_result);
1869     _igvn.replace_node(_callprojs->resproj[0], result_phi_rawoop);
1870   }
1871 
1872   // Plug slow-path into result merge point
1873   result_region->init_req( slow_result_path, ctrl);
1874   transform_later(result_region);
1875   if (allocation_has_use) {
1876     result_phi_rawoop->init_req(slow_result_path, slow_result);
1877     transform_later(result_phi_rawoop);
1878   }
1879   result_phi_rawmem->init_req(slow_result_path, _callprojs->fallthrough_memproj);
1880   transform_later(result_phi_rawmem);
1881   transform_later(result_phi_i_o);
1882   // This completes all paths into the result merge point
1883 }
1884 
1885 // Remove alloc node that has no uses.
1886 void PhaseMacroExpand::yank_alloc_node(AllocateNode* alloc) {
1887   Node* ctrl = alloc->in(TypeFunc::Control);
1888   Node* mem  = alloc->in(TypeFunc::Memory);
1889   Node* i_o  = alloc->in(TypeFunc::I_O);
1890 
1891   _callprojs = alloc->extract_projections(false /*separate_io_proj*/, false /*do_asserts*/);
1892   if (_callprojs->resproj[0] != nullptr) {
1893     for (DUIterator_Fast imax, i = _callprojs->resproj[0]->fast_outs(imax); i < imax; i++) {
1894       Node* use = _callprojs->resproj[0]->fast_out(i);
1895       use->isa_MemBar()->remove(&_igvn);
1896       --imax;
1897       --i; // back up iterator
1898     }
1899     assert(_callprojs->resproj[0]->outcnt() == 0, "all uses must be deleted");
1900     _igvn.remove_dead_node(_callprojs->resproj[0]);
1901   }
1902   if (_callprojs->fallthrough_catchproj != nullptr) {
1903     _igvn.replace_in_uses(_callprojs->fallthrough_catchproj, ctrl);
1904     _igvn.remove_dead_node(_callprojs->fallthrough_catchproj);
1905   }
1906   if (_callprojs->catchall_catchproj != nullptr) {
1907     _igvn.rehash_node_delayed(_callprojs->catchall_catchproj);
1908     _callprojs->catchall_catchproj->set_req(0, top());
1909   }
1910   if (_callprojs->fallthrough_proj != nullptr) {
1911     Node* catchnode = _callprojs->fallthrough_proj->unique_ctrl_out();
1912     _igvn.remove_dead_node(catchnode);
1913     _igvn.remove_dead_node(_callprojs->fallthrough_proj);
1914   }
1915   if (_callprojs->fallthrough_memproj != nullptr) {
1916     _igvn.replace_in_uses(_callprojs->fallthrough_memproj, mem);
1917     _igvn.remove_dead_node(_callprojs->fallthrough_memproj);
1918   }
1919   if (_callprojs->fallthrough_ioproj != nullptr) {
1920     _igvn.replace_in_uses(_callprojs->fallthrough_ioproj, i_o);
1921     _igvn.remove_dead_node(_callprojs->fallthrough_ioproj);
1922   }
1923   if (_callprojs->catchall_memproj != nullptr) {
1924     _igvn.rehash_node_delayed(_callprojs->catchall_memproj);
1925     _callprojs->catchall_memproj->set_req(0, top());
1926   }
1927   if (_callprojs->catchall_ioproj != nullptr) {
1928     _igvn.rehash_node_delayed(_callprojs->catchall_ioproj);
1929     _callprojs->catchall_ioproj->set_req(0, top());
1930   }
1931 #ifndef PRODUCT
1932   if (PrintEliminateAllocations) {
1933     if (alloc->is_AllocateArray()) {
1934       tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
1935     } else {
1936       tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
1937     }
1938   }
1939 #endif
1940   _igvn.remove_dead_node(alloc);
1941 }
1942 
1943 void PhaseMacroExpand::expand_initialize_membar(AllocateNode* alloc, InitializeNode* init,
1944                                                 Node*& fast_oop_ctrl, Node*& fast_oop_rawmem) {
1945   // If initialization is performed by an array copy, any required
1946   // MemBarStoreStore was already added. If the object does not
1947   // escape no need for a MemBarStoreStore. If the object does not
1948   // escape in its initializer and memory barrier (MemBarStoreStore or
1949   // stronger) is already added at exit of initializer, also no need
1950   // for a MemBarStoreStore. Otherwise we need a MemBarStoreStore
1951   // so that stores that initialize this object can't be reordered
1952   // with a subsequent store that makes this object accessible by
1953   // other threads.
1954   // Other threads include java threads and JVM internal threads
1955   // (for example concurrent GC threads). Current concurrent GC
1956   // implementation: G1 will not scan newly created object,
1957   // so it's safe to skip storestore barrier when allocation does
1958   // not escape.
1959   if (!alloc->does_not_escape_thread() &&
1960     !alloc->is_allocation_MemBar_redundant() &&
1961     (init == nullptr || !init->is_complete_with_arraycopy())) {
1962     if (init == nullptr || init->req() < InitializeNode::RawStores) {
1963       // No InitializeNode or no stores captured by zeroing
1964       // elimination. Simply add the MemBarStoreStore after object
1965       // initialization.
1966       // What we want is to prevent the compiler and the CPU from re-ordering the stores that initialize this object
1967       // with subsequent stores to any slice. As a consequence, this MemBar should capture the entire memory state at
1968       // this point in the IR and produce a new memory state that should cover all slices. However, the Initialize node
1969       // only captures/produces a partial memory state making it complicated to insert such a MemBar. Because
1970       // re-ordering by the compiler can't happen by construction (a later Store that publishes the just allocated
1971       // object reference is indirectly control dependent on the Initialize node), preventing reordering by the CPU is
1972       // sufficient. For that a MemBar on the raw memory slice is good enough.
1973       // If init is null, this allocation does have an InitializeNode but this logic can't locate it (see comment in
1974       // PhaseMacroExpand::initialize_object()).
1975       MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxRaw);
1976       transform_later(mb);
1977 
1978       mb->init_req(TypeFunc::Memory, fast_oop_rawmem);
1979       mb->init_req(TypeFunc::Control, fast_oop_ctrl);
1980       fast_oop_ctrl = new ProjNode(mb, TypeFunc::Control);
1981       transform_later(fast_oop_ctrl);
1982       fast_oop_rawmem = new ProjNode(mb, TypeFunc::Memory);
1983       transform_later(fast_oop_rawmem);
1984     } else {
1985       // Add the MemBarStoreStore after the InitializeNode so that
1986       // all stores performing the initialization that were moved
1987       // before the InitializeNode happen before the storestore
1988       // barrier.
1989 
1990       Node* init_ctrl = init->proj_out_or_null(TypeFunc::Control);
1991 
1992       // See comment above that explains why a raw memory MemBar is good enough.
1993       MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxRaw);
1994       transform_later(mb);
1995 
1996       Node* ctrl = new ProjNode(init, TypeFunc::Control);
1997       transform_later(ctrl);
1998       Node* old_raw_mem_proj = nullptr;
1999       auto find_raw_mem = [&](ProjNode* proj) {
2000         if (C->get_alias_index(proj->adr_type()) == Compile::AliasIdxRaw) {
2001           assert(old_raw_mem_proj == nullptr, "only one expected");
2002           old_raw_mem_proj = proj;
2003         }
2004       };
2005       init->for_each_proj(find_raw_mem, TypeFunc::Memory);
2006       assert(old_raw_mem_proj != nullptr, "should have found raw mem Proj");
2007       Node* raw_mem_proj = new ProjNode(init, TypeFunc::Memory);
2008       transform_later(raw_mem_proj);
2009 
2010       // The MemBarStoreStore depends on control and memory coming
2011       // from the InitializeNode
2012       mb->init_req(TypeFunc::Memory, raw_mem_proj);
2013       mb->init_req(TypeFunc::Control, ctrl);
2014 
2015       ctrl = new ProjNode(mb, TypeFunc::Control);
2016       transform_later(ctrl);
2017       Node* mem = new ProjNode(mb, TypeFunc::Memory);
2018       transform_later(mem);
2019 
2020       // All nodes that depended on the InitializeNode for control
2021       // and memory must now depend on the MemBarNode that itself
2022       // depends on the InitializeNode
2023       if (init_ctrl != nullptr) {
2024         _igvn.replace_node(init_ctrl, ctrl);
2025       }
2026       _igvn.replace_node(old_raw_mem_proj, mem);
2027     }
2028   }
2029 }
2030 
2031 void PhaseMacroExpand::expand_dtrace_alloc_probe(AllocateNode* alloc, Node* oop,
2032                                                 Node*& ctrl, Node*& rawmem) {
2033   if (C->env()->dtrace_alloc_probes()) {
2034     // Slow-path call
2035     int size = TypeFunc::Parms + 2;
2036     CallLeafNode *call = new CallLeafNode(OptoRuntime::dtrace_object_alloc_Type(),
2037                                           CAST_FROM_FN_PTR(address,
2038                                           static_cast<int (*)(JavaThread*, oopDesc*)>(SharedRuntime::dtrace_object_alloc)),
2039                                           "dtrace_object_alloc",
2040                                           TypeRawPtr::BOTTOM);
2041 
2042     // Get base of thread-local storage area
2043     Node* thread = new ThreadLocalNode();
2044     transform_later(thread);
2045 
2046     call->init_req(TypeFunc::Parms + 0, thread);
2047     call->init_req(TypeFunc::Parms + 1, oop);
2048     call->init_req(TypeFunc::Control, ctrl);
2049     call->init_req(TypeFunc::I_O    , top()); // does no i/o
2050     call->init_req(TypeFunc::Memory , rawmem);
2051     call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
2052     call->init_req(TypeFunc::FramePtr, alloc->in(TypeFunc::FramePtr));
2053     transform_later(call);
2054     ctrl = new ProjNode(call, TypeFunc::Control);
2055     transform_later(ctrl);
2056     rawmem = new ProjNode(call, TypeFunc::Memory);
2057     transform_later(rawmem);
2058   }
2059 }
2060 
2061 // Helper for PhaseMacroExpand::expand_allocate_common.
2062 // Initializes the newly-allocated storage.
2063 Node* PhaseMacroExpand::initialize_object(AllocateNode* alloc,
2064                                           Node* control, Node* rawmem, Node* object,
2065                                           Node* klass_node, Node* length,
2066                                           Node* size_in_bytes) {
2067   InitializeNode* init = alloc->initialization();
2068   // Store the klass & mark bits
2069   Node* mark_node = alloc->make_ideal_mark(&_igvn, control, rawmem);
2070   if (!mark_node->is_Con()) {
2071     transform_later(mark_node);
2072   }
2073   rawmem = make_store(control, rawmem, object, oopDesc::mark_offset_in_bytes(), mark_node, TypeX_X->basic_type());
2074 
2075   if (!UseCompactObjectHeaders) {
2076     rawmem = make_store(control, rawmem, object, oopDesc::klass_offset_in_bytes(), klass_node, T_METADATA);
2077   }
2078   int header_size = alloc->minimum_header_size();  // conservatively small
2079 
2080   // Array length
2081   if (length != nullptr) {         // Arrays need length field
2082     rawmem = make_store(control, rawmem, object, arrayOopDesc::length_offset_in_bytes(), length, T_INT);
2083     // conservatively small header size:
2084     header_size = arrayOopDesc::base_offset_in_bytes(T_BYTE);
2085     if (_igvn.type(klass_node)->isa_aryklassptr()) {   // we know the exact header size in most cases:
2086       BasicType elem = _igvn.type(klass_node)->is_klassptr()->as_instance_type()->isa_aryptr()->elem()->array_element_basic_type();
2087       if (is_reference_type(elem, true)) {
2088         elem = T_OBJECT;
2089       }
2090       header_size = Klass::layout_helper_header_size(Klass::array_layout_helper(elem));
2091     }
2092   }
2093 
2094   // Clear the object body, if necessary.
2095   if (init == nullptr) {
2096     // The init has somehow disappeared; be cautious and clear everything.
2097     //
2098     // This can happen if a node is allocated but an uncommon trap occurs
2099     // immediately.  In this case, the Initialize gets associated with the
2100     // trap, and may be placed in a different (outer) loop, if the Allocate
2101     // is in a loop.  If (this is rare) the inner loop gets unrolled, then
2102     // there can be two Allocates to one Initialize.  The answer in all these
2103     // edge cases is safety first.  It is always safe to clear immediately
2104     // within an Allocate, and then (maybe or maybe not) clear some more later.
2105     if (!(UseTLAB && ZeroTLAB)) {
2106       rawmem = ClearArrayNode::clear_memory(control, rawmem, object,
2107                                             alloc->in(AllocateNode::InitValue),
2108                                             alloc->in(AllocateNode::RawInitValue),
2109                                             header_size, size_in_bytes,
2110                                             &_igvn);
2111     }
2112   } else {
2113     if (!init->is_complete()) {
2114       // Try to win by zeroing only what the init does not store.
2115       // We can also try to do some peephole optimizations,
2116       // such as combining some adjacent subword stores.
2117       rawmem = init->complete_stores(control, rawmem, object,
2118                                      header_size, size_in_bytes, &_igvn);
2119     }
2120     // We have no more use for this link, since the AllocateNode goes away:
2121     init->set_req(InitializeNode::RawAddress, top());
2122     // (If we keep the link, it just confuses the register allocator,
2123     // who thinks he sees a real use of the address by the membar.)
2124   }
2125 
2126   return rawmem;
2127 }
2128 
2129 // Generate prefetch instructions for next allocations.
2130 Node* PhaseMacroExpand::prefetch_allocation(Node* i_o, Node*& needgc_false,
2131                                         Node*& contended_phi_rawmem,
2132                                         Node* old_eden_top, Node* new_eden_top,
2133                                         intx lines) {
2134    enum { fall_in_path = 1, pf_path = 2 };
2135    if( UseTLAB && AllocatePrefetchStyle == 2 ) {
2136       // Generate prefetch allocation with watermark check.
2137       // As an allocation hits the watermark, we will prefetch starting
2138       // at a "distance" away from watermark.
2139 
2140       Node *pf_region = new RegionNode(3);
2141       Node *pf_phi_rawmem = new PhiNode( pf_region, Type::MEMORY,
2142                                                 TypeRawPtr::BOTTOM );
2143       // I/O is used for Prefetch
2144       Node *pf_phi_abio = new PhiNode( pf_region, Type::ABIO );
2145 
2146       Node *thread = new ThreadLocalNode();
2147       transform_later(thread);
2148 
2149       Node *eden_pf_adr = new AddPNode( top()/*not oop*/, thread,
2150                    _igvn.MakeConX(in_bytes(JavaThread::tlab_pf_top_offset())) );
2151       transform_later(eden_pf_adr);
2152 
2153       Node *old_pf_wm = new LoadPNode(needgc_false,
2154                                    contended_phi_rawmem, eden_pf_adr,
2155                                    TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM,
2156                                    MemNode::unordered);
2157       transform_later(old_pf_wm);
2158 
2159       // check against new_eden_top
2160       Node *need_pf_cmp = new CmpPNode( new_eden_top, old_pf_wm );
2161       transform_later(need_pf_cmp);
2162       Node *need_pf_bol = new BoolNode( need_pf_cmp, BoolTest::ge );
2163       transform_later(need_pf_bol);
2164       IfNode *need_pf_iff = new IfNode( needgc_false, need_pf_bol,
2165                                        PROB_UNLIKELY_MAG(4), COUNT_UNKNOWN );
2166       transform_later(need_pf_iff);
2167 
2168       // true node, add prefetchdistance
2169       Node *need_pf_true = new IfTrueNode( need_pf_iff );
2170       transform_later(need_pf_true);
2171 
2172       Node *need_pf_false = new IfFalseNode( need_pf_iff );
2173       transform_later(need_pf_false);
2174 
2175       Node *new_pf_wmt = new AddPNode( top(), old_pf_wm,
2176                                     _igvn.MakeConX(AllocatePrefetchDistance) );
2177       transform_later(new_pf_wmt );
2178       new_pf_wmt->set_req(0, need_pf_true);
2179 
2180       Node *store_new_wmt = new StorePNode(need_pf_true,
2181                                        contended_phi_rawmem, eden_pf_adr,
2182                                        TypeRawPtr::BOTTOM, new_pf_wmt,
2183                                        MemNode::unordered);
2184       transform_later(store_new_wmt);
2185 
2186       // adding prefetches
2187       pf_phi_abio->init_req( fall_in_path, i_o );
2188 
2189       Node *prefetch_adr;
2190       Node *prefetch;
2191       uint step_size = AllocatePrefetchStepSize;
2192       uint distance = 0;
2193 
2194       for ( intx i = 0; i < lines; i++ ) {
2195         prefetch_adr = new AddPNode( old_pf_wm, new_pf_wmt,
2196                                             _igvn.MakeConX(distance) );
2197         transform_later(prefetch_adr);
2198         prefetch = new PrefetchAllocationNode( i_o, prefetch_adr );
2199         transform_later(prefetch);
2200         distance += step_size;
2201         i_o = prefetch;
2202       }
2203       pf_phi_abio->set_req( pf_path, i_o );
2204 
2205       pf_region->init_req( fall_in_path, need_pf_false );
2206       pf_region->init_req( pf_path, need_pf_true );
2207 
2208       pf_phi_rawmem->init_req( fall_in_path, contended_phi_rawmem );
2209       pf_phi_rawmem->init_req( pf_path, store_new_wmt );
2210 
2211       transform_later(pf_region);
2212       transform_later(pf_phi_rawmem);
2213       transform_later(pf_phi_abio);
2214 
2215       needgc_false = pf_region;
2216       contended_phi_rawmem = pf_phi_rawmem;
2217       i_o = pf_phi_abio;
2218    } else if( UseTLAB && AllocatePrefetchStyle == 3 ) {
2219       // Insert a prefetch instruction for each allocation.
2220       // This code is used to generate 1 prefetch instruction per cache line.
2221 
2222       // Generate several prefetch instructions.
2223       uint step_size = AllocatePrefetchStepSize;
2224       uint distance = AllocatePrefetchDistance;
2225 
2226       // Next cache address.
2227       Node *cache_adr = new AddPNode(old_eden_top, old_eden_top,
2228                                      _igvn.MakeConX(step_size + distance));
2229       transform_later(cache_adr);
2230       cache_adr = new CastP2XNode(needgc_false, cache_adr);
2231       transform_later(cache_adr);
2232       // Address is aligned to execute prefetch to the beginning of cache line size
2233       // (it is important when BIS instruction is used on SPARC as prefetch).
2234       Node* mask = _igvn.MakeConX(~(intptr_t)(step_size-1));
2235       cache_adr = new AndXNode(cache_adr, mask);
2236       transform_later(cache_adr);
2237       cache_adr = new CastX2PNode(cache_adr);
2238       transform_later(cache_adr);
2239 
2240       // Prefetch
2241       Node *prefetch = new PrefetchAllocationNode( contended_phi_rawmem, cache_adr );
2242       prefetch->set_req(0, needgc_false);
2243       transform_later(prefetch);
2244       contended_phi_rawmem = prefetch;
2245       Node *prefetch_adr;
2246       distance = step_size;
2247       for ( intx i = 1; i < lines; i++ ) {
2248         prefetch_adr = new AddPNode( cache_adr, cache_adr,
2249                                             _igvn.MakeConX(distance) );
2250         transform_later(prefetch_adr);
2251         prefetch = new PrefetchAllocationNode( contended_phi_rawmem, prefetch_adr );
2252         transform_later(prefetch);
2253         distance += step_size;
2254         contended_phi_rawmem = prefetch;
2255       }
2256    } else if( AllocatePrefetchStyle > 0 ) {
2257       // Insert a prefetch for each allocation only on the fast-path
2258       Node *prefetch_adr;
2259       Node *prefetch;
2260       // Generate several prefetch instructions.
2261       uint step_size = AllocatePrefetchStepSize;
2262       uint distance = AllocatePrefetchDistance;
2263       for ( intx i = 0; i < lines; i++ ) {
2264         prefetch_adr = new AddPNode( old_eden_top, new_eden_top,
2265                                             _igvn.MakeConX(distance) );
2266         transform_later(prefetch_adr);
2267         prefetch = new PrefetchAllocationNode( i_o, prefetch_adr );
2268         // Do not let it float too high, since if eden_top == eden_end,
2269         // both might be null.
2270         if( i == 0 ) { // Set control for first prefetch, next follows it
2271           prefetch->init_req(0, needgc_false);
2272         }
2273         transform_later(prefetch);
2274         distance += step_size;
2275         i_o = prefetch;
2276       }
2277    }
2278    return i_o;
2279 }
2280 
2281 
2282 void PhaseMacroExpand::expand_allocate(AllocateNode *alloc) {
2283   expand_allocate_common(alloc, nullptr, nullptr,
2284                          OptoRuntime::new_instance_Type(),
2285                          OptoRuntime::new_instance_Java(), nullptr);
2286 }
2287 
2288 void PhaseMacroExpand::expand_allocate_array(AllocateArrayNode *alloc) {
2289   Node* length = alloc->in(AllocateNode::ALength);
2290   Node* valid_length_test = alloc->in(AllocateNode::ValidLengthTest);
2291   InitializeNode* init = alloc->initialization();
2292   Node* klass_node = alloc->in(AllocateNode::KlassNode);
2293   Node* init_value = alloc->in(AllocateNode::InitValue);
2294   const TypeAryKlassPtr* ary_klass_t = _igvn.type(klass_node)->isa_aryklassptr();
2295   assert(!ary_klass_t || !ary_klass_t->klass_is_exact() || !ary_klass_t->exact_klass()->is_obj_array_klass() ||
2296          ary_klass_t->is_refined_type(), "Must be a refined array klass");
2297   const TypeFunc* slow_call_type;
2298   address slow_call_address;  // Address of slow call
2299   if (init != nullptr && init->is_complete_with_arraycopy() &&
2300       ary_klass_t && ary_klass_t->elem()->isa_klassptr() == nullptr) {
2301     // Don't zero type array during slow allocation in VM since
2302     // it will be initialized later by arraycopy in compiled code.
2303     slow_call_address = OptoRuntime::new_array_nozero_Java();
2304     slow_call_type = OptoRuntime::new_array_nozero_Type();
2305   } else {
2306     slow_call_address = OptoRuntime::new_array_Java();
2307     slow_call_type = OptoRuntime::new_array_Type();
2308 
2309     if (init_value == nullptr) {
2310       init_value = _igvn.zerocon(T_OBJECT);
2311     } else if (UseCompressedOops) {
2312       init_value = transform_later(new DecodeNNode(init_value, init_value->bottom_type()->make_ptr()));
2313     }
2314   }
2315   expand_allocate_common(alloc, length, init_value,
2316                          slow_call_type,
2317                          slow_call_address, valid_length_test);
2318 }
2319 
2320 //-------------------mark_eliminated_box----------------------------------
2321 //
2322 // During EA obj may point to several objects but after few ideal graph
2323 // transformations (CCP) it may point to only one non escaping object
2324 // (but still using phi), corresponding locks and unlocks will be marked
2325 // for elimination. Later obj could be replaced with a new node (new phi)
2326 // and which does not have escape information. And later after some graph
2327 // reshape other locks and unlocks (which were not marked for elimination
2328 // before) are connected to this new obj (phi) but they still will not be
2329 // marked for elimination since new obj has no escape information.
2330 // Mark all associated (same box and obj) lock and unlock nodes for
2331 // elimination if some of them marked already.
2332 void PhaseMacroExpand::mark_eliminated_box(Node* box, Node* obj) {
2333   BoxLockNode* oldbox = box->as_BoxLock();
2334   if (oldbox->is_eliminated()) {
2335     return; // This BoxLock node was processed already.
2336   }
2337   assert(!oldbox->is_unbalanced(), "this should not be called for unbalanced region");
2338   // New implementation (EliminateNestedLocks) has separate BoxLock
2339   // node for each locked region so mark all associated locks/unlocks as
2340   // eliminated even if different objects are referenced in one locked region
2341   // (for example, OSR compilation of nested loop inside locked scope).
2342   if (EliminateNestedLocks ||
2343       oldbox->as_BoxLock()->is_simple_lock_region(nullptr, obj, nullptr)) {
2344     // Box is used only in one lock region. Mark this box as eliminated.
2345     oldbox->set_local();      // This verifies correct state of BoxLock
2346     _igvn.hash_delete(oldbox);
2347     oldbox->set_eliminated(); // This changes box's hash value
2348      _igvn.hash_insert(oldbox);
2349 
2350     for (uint i = 0; i < oldbox->outcnt(); i++) {
2351       Node* u = oldbox->raw_out(i);
2352       if (u->is_AbstractLock() && !u->as_AbstractLock()->is_non_esc_obj()) {
2353         AbstractLockNode* alock = u->as_AbstractLock();
2354         // Check lock's box since box could be referenced by Lock's debug info.
2355         if (alock->box_node() == oldbox) {
2356           // Mark eliminated all related locks and unlocks.
2357 #ifdef ASSERT
2358           alock->log_lock_optimization(C, "eliminate_lock_set_non_esc4");
2359 #endif
2360           alock->set_non_esc_obj();
2361         }
2362       }
2363     }
2364     return;
2365   }
2366 
2367   // Create new "eliminated" BoxLock node and use it in monitor debug info
2368   // instead of oldbox for the same object.
2369   BoxLockNode* newbox = oldbox->clone()->as_BoxLock();
2370 
2371   // Note: BoxLock node is marked eliminated only here and it is used
2372   // to indicate that all associated lock and unlock nodes are marked
2373   // for elimination.
2374   newbox->set_local(); // This verifies correct state of BoxLock
2375   newbox->set_eliminated();
2376   transform_later(newbox);
2377 
2378   // Replace old box node with new box for all users of the same object.
2379   for (uint i = 0; i < oldbox->outcnt();) {
2380     bool next_edge = true;
2381 
2382     Node* u = oldbox->raw_out(i);
2383     if (u->is_AbstractLock()) {
2384       AbstractLockNode* alock = u->as_AbstractLock();
2385       if (alock->box_node() == oldbox && alock->obj_node()->eqv_uncast(obj)) {
2386         // Replace Box and mark eliminated all related locks and unlocks.
2387 #ifdef ASSERT
2388         alock->log_lock_optimization(C, "eliminate_lock_set_non_esc5");
2389 #endif
2390         alock->set_non_esc_obj();
2391         _igvn.rehash_node_delayed(alock);
2392         alock->set_box_node(newbox);
2393         next_edge = false;
2394       }
2395     }
2396     if (u->is_FastLock() && u->as_FastLock()->obj_node()->eqv_uncast(obj)) {
2397       FastLockNode* flock = u->as_FastLock();
2398       assert(flock->box_node() == oldbox, "sanity");
2399       _igvn.rehash_node_delayed(flock);
2400       flock->set_box_node(newbox);
2401       next_edge = false;
2402     }
2403 
2404     // Replace old box in monitor debug info.
2405     if (u->is_SafePoint() && u->as_SafePoint()->jvms()) {
2406       SafePointNode* sfn = u->as_SafePoint();
2407       JVMState* youngest_jvms = sfn->jvms();
2408       int max_depth = youngest_jvms->depth();
2409       for (int depth = 1; depth <= max_depth; depth++) {
2410         JVMState* jvms = youngest_jvms->of_depth(depth);
2411         int num_mon  = jvms->nof_monitors();
2412         // Loop over monitors
2413         for (int idx = 0; idx < num_mon; idx++) {
2414           Node* obj_node = sfn->monitor_obj(jvms, idx);
2415           Node* box_node = sfn->monitor_box(jvms, idx);
2416           if (box_node == oldbox && obj_node->eqv_uncast(obj)) {
2417             int j = jvms->monitor_box_offset(idx);
2418             _igvn.replace_input_of(u, j, newbox);
2419             next_edge = false;
2420           }
2421         }
2422       }
2423     }
2424     if (next_edge) i++;
2425   }
2426 }
2427 
2428 //-----------------------mark_eliminated_locking_nodes-----------------------
2429 void PhaseMacroExpand::mark_eliminated_locking_nodes(AbstractLockNode *alock) {
2430   if (!alock->is_balanced()) {
2431     return; // Can't do any more elimination for this locking region
2432   }
2433   if (EliminateNestedLocks) {
2434     if (alock->is_nested()) {
2435        assert(alock->box_node()->as_BoxLock()->is_eliminated(), "sanity");
2436        return;
2437     } else if (!alock->is_non_esc_obj()) { // Not eliminated or coarsened
2438       // Only Lock node has JVMState needed here.
2439       // Not that preceding claim is documented anywhere else.
2440       if (alock->jvms() != nullptr) {
2441         if (alock->as_Lock()->is_nested_lock_region()) {
2442           // Mark eliminated related nested locks and unlocks.
2443           Node* obj = alock->obj_node();
2444           BoxLockNode* box_node = alock->box_node()->as_BoxLock();
2445           assert(!box_node->is_eliminated(), "should not be marked yet");
2446           // Note: BoxLock node is marked eliminated only here
2447           // and it is used to indicate that all associated lock
2448           // and unlock nodes are marked for elimination.
2449           box_node->set_eliminated(); // Box's hash is always NO_HASH here
2450           for (uint i = 0; i < box_node->outcnt(); i++) {
2451             Node* u = box_node->raw_out(i);
2452             if (u->is_AbstractLock()) {
2453               alock = u->as_AbstractLock();
2454               if (alock->box_node() == box_node) {
2455                 // Verify that this Box is referenced only by related locks.
2456                 assert(alock->obj_node()->eqv_uncast(obj), "");
2457                 // Mark all related locks and unlocks.
2458 #ifdef ASSERT
2459                 alock->log_lock_optimization(C, "eliminate_lock_set_nested");
2460 #endif
2461                 alock->set_nested();
2462               }
2463             }
2464           }
2465         } else {
2466 #ifdef ASSERT
2467           alock->log_lock_optimization(C, "eliminate_lock_NOT_nested_lock_region");
2468           if (C->log() != nullptr)
2469             alock->as_Lock()->is_nested_lock_region(C); // rerun for debugging output
2470 #endif
2471         }
2472       }
2473       return;
2474     }
2475     // Process locks for non escaping object
2476     assert(alock->is_non_esc_obj(), "");
2477   } // EliminateNestedLocks
2478 
2479   if (alock->is_non_esc_obj()) { // Lock is used for non escaping object
2480     // Look for all locks of this object and mark them and
2481     // corresponding BoxLock nodes as eliminated.
2482     Node* obj = alock->obj_node();
2483     for (uint j = 0; j < obj->outcnt(); j++) {
2484       Node* o = obj->raw_out(j);
2485       if (o->is_AbstractLock() &&
2486           o->as_AbstractLock()->obj_node()->eqv_uncast(obj)) {
2487         alock = o->as_AbstractLock();
2488         Node* box = alock->box_node();
2489         // Replace old box node with new eliminated box for all users
2490         // of the same object and mark related locks as eliminated.
2491         mark_eliminated_box(box, obj);
2492       }
2493     }
2494   }
2495 }
2496 
2497 // we have determined that this lock/unlock can be eliminated, we simply
2498 // eliminate the node without expanding it.
2499 //
2500 // Note:  The membar's associated with the lock/unlock are currently not
2501 //        eliminated.  This should be investigated as a future enhancement.
2502 //
2503 bool PhaseMacroExpand::eliminate_locking_node(AbstractLockNode *alock) {
2504 
2505   if (!alock->is_eliminated()) {
2506     return false;
2507   }
2508 #ifdef ASSERT
2509   if (!alock->is_coarsened()) {
2510     // Check that new "eliminated" BoxLock node is created.
2511     BoxLockNode* oldbox = alock->box_node()->as_BoxLock();
2512     assert(oldbox->is_eliminated(), "should be done already");
2513   }
2514 #endif
2515 
2516   alock->log_lock_optimization(C, "eliminate_lock");
2517 
2518 #ifndef PRODUCT
2519   if (PrintEliminateLocks) {
2520     tty->print_cr("++++ Eliminated: %d %s '%s'", alock->_idx, (alock->is_Lock() ? "Lock" : "Unlock"), alock->kind_as_string());
2521   }
2522 #endif
2523 
2524   Node* mem  = alock->in(TypeFunc::Memory);
2525   Node* ctrl = alock->in(TypeFunc::Control);
2526   guarantee(ctrl != nullptr, "missing control projection, cannot replace_node() with null");
2527 
2528   _callprojs = alock->extract_projections(false /*separate_io_proj*/, false /*do_asserts*/);
2529   // There are 2 projections from the lock.  The lock node will
2530   // be deleted when its last use is subsumed below.
2531   assert(alock->outcnt() == 2 &&
2532          _callprojs->fallthrough_proj != nullptr &&
2533          _callprojs->fallthrough_memproj != nullptr,
2534          "Unexpected projections from Lock/Unlock");
2535 
2536   Node* fallthroughproj = _callprojs->fallthrough_proj;
2537   Node* memproj_fallthrough = _callprojs->fallthrough_memproj;
2538 
2539   // The memory projection from a lock/unlock is RawMem
2540   // The input to a Lock is merged memory, so extract its RawMem input
2541   // (unless the MergeMem has been optimized away.)
2542   if (alock->is_Lock()) {
2543     // Search for MemBarAcquireLock node and delete it also.
2544     MemBarNode* membar = fallthroughproj->unique_ctrl_out()->as_MemBar();
2545     assert(membar != nullptr && membar->Opcode() == Op_MemBarAcquireLock, "");
2546     Node* ctrlproj = membar->proj_out(TypeFunc::Control);
2547     Node* memproj = membar->proj_out(TypeFunc::Memory);
2548     _igvn.replace_node(ctrlproj, fallthroughproj);
2549     _igvn.replace_node(memproj, memproj_fallthrough);
2550 
2551     // Delete FastLock node also if this Lock node is unique user
2552     // (a loop peeling may clone a Lock node).
2553     Node* flock = alock->as_Lock()->fastlock_node();
2554     if (flock->outcnt() == 1) {
2555       assert(flock->unique_out() == alock, "sanity");
2556       _igvn.replace_node(flock, top());
2557     }
2558   }
2559 
2560   // Search for MemBarReleaseLock node and delete it also.
2561   if (alock->is_Unlock() && ctrl->is_Proj() && ctrl->in(0)->is_MemBar()) {
2562     MemBarNode* membar = ctrl->in(0)->as_MemBar();
2563     assert(membar->Opcode() == Op_MemBarReleaseLock &&
2564            mem->is_Proj() && membar == mem->in(0), "");
2565     _igvn.replace_node(fallthroughproj, ctrl);
2566     _igvn.replace_node(memproj_fallthrough, mem);
2567     fallthroughproj = ctrl;
2568     memproj_fallthrough = mem;
2569     ctrl = membar->in(TypeFunc::Control);
2570     mem  = membar->in(TypeFunc::Memory);
2571   }
2572 
2573   _igvn.replace_node(fallthroughproj, ctrl);
2574   _igvn.replace_node(memproj_fallthrough, mem);
2575   return true;
2576 }
2577 
2578 
2579 //------------------------------expand_lock_node----------------------
2580 void PhaseMacroExpand::expand_lock_node(LockNode *lock) {
2581 
2582   Node* ctrl = lock->in(TypeFunc::Control);
2583   Node* mem = lock->in(TypeFunc::Memory);
2584   Node* obj = lock->obj_node();
2585   Node* box = lock->box_node();
2586   Node* flock = lock->fastlock_node();
2587 
2588   assert(!box->as_BoxLock()->is_eliminated(), "sanity");
2589 
2590   // Make the merge point
2591   Node *region;
2592   Node *mem_phi;
2593   Node *slow_path;
2594 
2595   region  = new RegionNode(3);
2596   // create a Phi for the memory state
2597   mem_phi = new PhiNode( region, Type::MEMORY, TypeRawPtr::BOTTOM);
2598 
2599   // Optimize test; set region slot 2
2600   slow_path = opt_bits_test(ctrl, region, 2, flock);
2601   mem_phi->init_req(2, mem);
2602 
2603   // Make slow path call
2604   CallNode* call = make_slow_call(lock, OptoRuntime::complete_monitor_enter_Type(),
2605                                   OptoRuntime::complete_monitor_locking_Java(), nullptr, slow_path,
2606                                   obj, box, nullptr);
2607 
2608   _callprojs = call->extract_projections(false /*separate_io_proj*/, false /*do_asserts*/);
2609 
2610   // Slow path can only throw asynchronous exceptions, which are always
2611   // de-opted.  So the compiler thinks the slow-call can never throw an
2612   // exception.  If it DOES throw an exception we would need the debug
2613   // info removed first (since if it throws there is no monitor).
2614   assert(_callprojs->fallthrough_ioproj == nullptr && _callprojs->catchall_ioproj == nullptr &&
2615          _callprojs->catchall_memproj == nullptr && _callprojs->catchall_catchproj == nullptr, "Unexpected projection from Lock");
2616 
2617   // Capture slow path
2618   // disconnect fall-through projection from call and create a new one
2619   // hook up users of fall-through projection to region
2620   Node *slow_ctrl = _callprojs->fallthrough_proj->clone();
2621   transform_later(slow_ctrl);
2622   _igvn.hash_delete(_callprojs->fallthrough_proj);
2623   _callprojs->fallthrough_proj->disconnect_inputs(C);
2624   region->init_req(1, slow_ctrl);
2625   // region inputs are now complete
2626   transform_later(region);
2627   _igvn.replace_node(_callprojs->fallthrough_proj, region);
2628 
2629   Node *memproj = transform_later(new ProjNode(call, TypeFunc::Memory));
2630 
2631   mem_phi->init_req(1, memproj);
2632 
2633   transform_later(mem_phi);
2634 
2635   _igvn.replace_node(_callprojs->fallthrough_memproj, mem_phi);
2636 }
2637 
2638 //------------------------------expand_unlock_node----------------------
2639 void PhaseMacroExpand::expand_unlock_node(UnlockNode *unlock) {
2640 
2641   Node* ctrl = unlock->in(TypeFunc::Control);
2642   Node* mem = unlock->in(TypeFunc::Memory);
2643   Node* obj = unlock->obj_node();
2644   Node* box = unlock->box_node();
2645 
2646   assert(!box->as_BoxLock()->is_eliminated(), "sanity");
2647 
2648   // No need for a null check on unlock
2649 
2650   // Make the merge point
2651   Node *region;
2652   Node *mem_phi;
2653 
2654   region  = new RegionNode(3);
2655   // create a Phi for the memory state
2656   mem_phi = new PhiNode( region, Type::MEMORY, TypeRawPtr::BOTTOM);
2657 
2658   FastUnlockNode *funlock = new FastUnlockNode( ctrl, obj, box );
2659   funlock = transform_later( funlock )->as_FastUnlock();
2660   // Optimize test; set region slot 2
2661   Node *slow_path = opt_bits_test(ctrl, region, 2, funlock);
2662   Node *thread = transform_later(new ThreadLocalNode());
2663 
2664   CallNode *call = make_slow_call((CallNode *) unlock, OptoRuntime::complete_monitor_exit_Type(),
2665                                   CAST_FROM_FN_PTR(address, SharedRuntime::complete_monitor_unlocking_C),
2666                                   "complete_monitor_unlocking_C", slow_path, obj, box, thread);
2667 
2668   _callprojs = call->extract_projections(false /*separate_io_proj*/, false /*do_asserts*/);
2669   assert(_callprojs->fallthrough_ioproj == nullptr && _callprojs->catchall_ioproj == nullptr &&
2670          _callprojs->catchall_memproj == nullptr && _callprojs->catchall_catchproj == nullptr, "Unexpected projection from Lock");
2671 
2672   // No exceptions for unlocking
2673   // Capture slow path
2674   // disconnect fall-through projection from call and create a new one
2675   // hook up users of fall-through projection to region
2676   Node *slow_ctrl = _callprojs->fallthrough_proj->clone();
2677   transform_later(slow_ctrl);
2678   _igvn.hash_delete(_callprojs->fallthrough_proj);
2679   _callprojs->fallthrough_proj->disconnect_inputs(C);
2680   region->init_req(1, slow_ctrl);
2681   // region inputs are now complete
2682   transform_later(region);
2683   _igvn.replace_node(_callprojs->fallthrough_proj, region);
2684 
2685   Node *memproj = transform_later(new ProjNode(call, TypeFunc::Memory) );
2686   mem_phi->init_req(1, memproj );
2687   mem_phi->init_req(2, mem);
2688   transform_later(mem_phi);
2689 
2690   _igvn.replace_node(_callprojs->fallthrough_memproj, mem_phi);
2691 }
2692 
2693 // An inline type might be returned from the call but we don't know its
2694 // type. Either we get a buffered inline type (and nothing needs to be done)
2695 // or one of the values being returned is the klass of the inline type
2696 // and we need to allocate an inline type instance of that type and
2697 // initialize it with other values being returned. In that case, we
2698 // first try a fast path allocation and initialize the value with the
2699 // inline klass's pack handler or we fall back to a runtime call.
2700 void PhaseMacroExpand::expand_mh_intrinsic_return(CallStaticJavaNode* call) {
2701   assert(call->method()->is_method_handle_intrinsic(), "must be a method handle intrinsic call");
2702   Node* ret = call->proj_out_or_null(TypeFunc::Parms);
2703   if (ret == nullptr) {
2704     return;
2705   }
2706   const TypeFunc* tf = call->_tf;
2707   const TypeTuple* domain = OptoRuntime::store_inline_type_fields_Type()->domain_cc();
2708   const TypeFunc* new_tf = TypeFunc::make(tf->domain_sig(), tf->domain_cc(), tf->range_sig(), domain);
2709   call->_tf = new_tf;
2710   // Make sure the change of type is applied before projections are processed by igvn
2711   _igvn.set_type(call, call->Value(&_igvn));
2712   _igvn.set_type(ret, ret->Value(&_igvn));
2713 
2714   // Before any new projection is added:
2715   CallProjections* projs = call->extract_projections(true, true);
2716 
2717   // Create temporary hook nodes that will be replaced below.
2718   // Add an input to prevent hook nodes from being dead.
2719   Node* ctl = new Node(call);
2720   Node* mem = new Node(ctl);
2721   Node* io = new Node(ctl);
2722   Node* ex_ctl = new Node(ctl);
2723   Node* ex_mem = new Node(ctl);
2724   Node* ex_io = new Node(ctl);
2725   Node* res = new Node(ctl);
2726 
2727   // Allocate a new buffered inline type only if a new one is not returned
2728   Node* cast = transform_later(new CastP2XNode(ctl, res));
2729   Node* mask = MakeConX(0x1);
2730   Node* masked = transform_later(new AndXNode(cast, mask));
2731   Node* cmp = transform_later(new CmpXNode(masked, mask));
2732   Node* bol = transform_later(new BoolNode(cmp, BoolTest::eq));
2733   IfNode* allocation_iff = new IfNode(ctl, bol, PROB_MAX, COUNT_UNKNOWN);
2734   transform_later(allocation_iff);
2735   Node* allocation_ctl = transform_later(new IfTrueNode(allocation_iff));
2736   Node* no_allocation_ctl = transform_later(new IfFalseNode(allocation_iff));
2737   Node* no_allocation_res = transform_later(new CheckCastPPNode(no_allocation_ctl, res, TypeInstPtr::BOTTOM));
2738 
2739   // Try to allocate a new buffered inline instance either from TLAB or eden space
2740   Node* needgc_ctrl = nullptr; // needgc means slowcase, i.e. allocation failed
2741   CallLeafNoFPNode* handler_call;
2742   const bool alloc_in_place = UseTLAB;
2743   if (alloc_in_place) {
2744     Node* fast_oop_ctrl = nullptr;
2745     Node* fast_oop_rawmem = nullptr;
2746     Node* mask2 = MakeConX(-2);
2747     Node* masked2 = transform_later(new AndXNode(cast, mask2));
2748     Node* rawklassptr = transform_later(new CastX2PNode(masked2));
2749     Node* klass_node = transform_later(new CheckCastPPNode(allocation_ctl, rawklassptr, TypeInstKlassPtr::OBJECT_OR_NULL));
2750     Node* layout_val = make_load(nullptr, mem, klass_node, in_bytes(Klass::layout_helper_offset()), TypeInt::INT, T_INT);
2751     Node* size_in_bytes = ConvI2X(layout_val);
2752     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
2753     Node* fast_oop = bs->obj_allocate(this, mem, allocation_ctl, size_in_bytes, io, needgc_ctrl,
2754                                       fast_oop_ctrl, fast_oop_rawmem,
2755                                       AllocateInstancePrefetchLines);
2756     // Allocation succeed, initialize buffered inline instance header firstly,
2757     // and then initialize its fields with an inline class specific handler
2758     Node* mark_word_node;
2759     if (UseCompactObjectHeaders) {
2760       // COH: We need to load the prototype from the klass at runtime since it encodes the klass pointer already.
2761       mark_word_node = make_load(fast_oop_ctrl, fast_oop_rawmem, klass_node, in_bytes(Klass::prototype_header_offset()), TypeRawPtr::BOTTOM, T_ADDRESS);
2762     } else {
2763       // Otherwise, use the static prototype.
2764       mark_word_node = makecon(TypeRawPtr::make((address)markWord::inline_type_prototype().value()));
2765     }
2766 
2767     fast_oop_rawmem = make_store(fast_oop_ctrl, fast_oop_rawmem, fast_oop, oopDesc::mark_offset_in_bytes(), mark_word_node, T_ADDRESS);
2768     if (!UseCompactObjectHeaders) {
2769       // COH: Everything is encoded in the mark word, so nothing left to do.
2770       fast_oop_rawmem = make_store(fast_oop_ctrl, fast_oop_rawmem, fast_oop, oopDesc::klass_offset_in_bytes(), klass_node, T_METADATA);
2771       if (UseCompressedClassPointers) {
2772         fast_oop_rawmem = make_store(fast_oop_ctrl, fast_oop_rawmem, fast_oop, oopDesc::klass_gap_offset_in_bytes(), intcon(0), T_INT);
2773       }
2774     }
2775     Node* members  = make_load(fast_oop_ctrl, fast_oop_rawmem, klass_node, in_bytes(InlineKlass::adr_members_offset()), TypeRawPtr::BOTTOM, T_ADDRESS);
2776     Node* pack_handler = make_load(fast_oop_ctrl, fast_oop_rawmem, members, in_bytes(InlineKlass::pack_handler_offset()), TypeRawPtr::BOTTOM, T_ADDRESS);
2777     handler_call = new CallLeafNoFPNode(OptoRuntime::pack_inline_type_Type(),
2778                                         nullptr,
2779                                         "pack handler",
2780                                         TypeRawPtr::BOTTOM);
2781     handler_call->init_req(TypeFunc::Control, fast_oop_ctrl);
2782     handler_call->init_req(TypeFunc::Memory, fast_oop_rawmem);
2783     handler_call->init_req(TypeFunc::I_O, top());
2784     handler_call->init_req(TypeFunc::FramePtr, call->in(TypeFunc::FramePtr));
2785     handler_call->init_req(TypeFunc::ReturnAdr, top());
2786     handler_call->init_req(TypeFunc::Parms, pack_handler);
2787     handler_call->init_req(TypeFunc::Parms+1, fast_oop);
2788   } else {
2789     needgc_ctrl = allocation_ctl;
2790   }
2791 
2792   // Allocation failed, fall back to a runtime call
2793   CallStaticJavaNode* slow_call = new CallStaticJavaNode(OptoRuntime::store_inline_type_fields_Type(),
2794                                                          StubRoutines::store_inline_type_fields_to_buf(),
2795                                                          "store_inline_type_fields",
2796                                                          TypePtr::BOTTOM);
2797   slow_call->init_req(TypeFunc::Control, needgc_ctrl);
2798   slow_call->init_req(TypeFunc::Memory, mem);
2799   slow_call->init_req(TypeFunc::I_O, io);
2800   slow_call->init_req(TypeFunc::FramePtr, call->in(TypeFunc::FramePtr));
2801   slow_call->init_req(TypeFunc::ReturnAdr, call->in(TypeFunc::ReturnAdr));
2802   slow_call->init_req(TypeFunc::Parms, res);
2803 
2804   Node* slow_ctl = transform_later(new ProjNode(slow_call, TypeFunc::Control));
2805   Node* slow_mem = transform_later(new ProjNode(slow_call, TypeFunc::Memory));
2806   Node* slow_io = transform_later(new ProjNode(slow_call, TypeFunc::I_O));
2807   Node* slow_res = transform_later(new ProjNode(slow_call, TypeFunc::Parms));
2808   Node* slow_catc = transform_later(new CatchNode(slow_ctl, slow_io, 2));
2809   Node* slow_norm = transform_later(new CatchProjNode(slow_catc, CatchProjNode::fall_through_index, CatchProjNode::no_handler_bci));
2810   Node* slow_excp = transform_later(new CatchProjNode(slow_catc, CatchProjNode::catch_all_index,    CatchProjNode::no_handler_bci));
2811 
2812   Node* ex_r = new RegionNode(3);
2813   Node* ex_mem_phi = new PhiNode(ex_r, Type::MEMORY, TypePtr::BOTTOM);
2814   Node* ex_io_phi = new PhiNode(ex_r, Type::ABIO);
2815   ex_r->init_req(1, slow_excp);
2816   ex_mem_phi->init_req(1, slow_mem);
2817   ex_io_phi->init_req(1, slow_io);
2818   ex_r->init_req(2, ex_ctl);
2819   ex_mem_phi->init_req(2, ex_mem);
2820   ex_io_phi->init_req(2, ex_io);
2821   transform_later(ex_r);
2822   transform_later(ex_mem_phi);
2823   transform_later(ex_io_phi);
2824 
2825   // We don't know how many values are returned. This assumes the
2826   // worst case, that all available registers are used.
2827   for (uint i = TypeFunc::Parms+1; i < domain->cnt(); i++) {
2828     if (domain->field_at(i) == Type::HALF) {
2829       slow_call->init_req(i, top());
2830       if (alloc_in_place) {
2831         handler_call->init_req(i+1, top());
2832       }
2833       continue;
2834     }
2835     Node* proj = transform_later(new ProjNode(call, i));
2836     slow_call->init_req(i, proj);
2837     if (alloc_in_place) {
2838       handler_call->init_req(i+1, proj);
2839     }
2840   }
2841   // We can safepoint at that new call
2842   slow_call->copy_call_debug_info(&_igvn, call);
2843   transform_later(slow_call);
2844   if (alloc_in_place) {
2845     transform_later(handler_call);
2846   }
2847 
2848   Node* fast_ctl = nullptr;
2849   Node* fast_res = nullptr;
2850   MergeMemNode* fast_mem = nullptr;
2851   if (alloc_in_place) {
2852     fast_ctl = transform_later(new ProjNode(handler_call, TypeFunc::Control));
2853     Node* rawmem = transform_later(new ProjNode(handler_call, TypeFunc::Memory));
2854     fast_res = transform_later(new ProjNode(handler_call, TypeFunc::Parms));
2855     fast_mem = MergeMemNode::make(mem);
2856     fast_mem->set_memory_at(Compile::AliasIdxRaw, rawmem);
2857     transform_later(fast_mem);
2858   }
2859 
2860   Node* r = new RegionNode(alloc_in_place ? 4 : 3);
2861   Node* mem_phi = new PhiNode(r, Type::MEMORY, TypePtr::BOTTOM);
2862   Node* io_phi = new PhiNode(r, Type::ABIO);
2863   Node* res_phi = new PhiNode(r, TypeInstPtr::BOTTOM);
2864   r->init_req(1, no_allocation_ctl);
2865   mem_phi->init_req(1, mem);
2866   io_phi->init_req(1, io);
2867   res_phi->init_req(1, no_allocation_res);
2868   r->init_req(2, slow_norm);
2869   mem_phi->init_req(2, slow_mem);
2870   io_phi->init_req(2, slow_io);
2871   res_phi->init_req(2, slow_res);
2872   if (alloc_in_place) {
2873     r->init_req(3, fast_ctl);
2874     mem_phi->init_req(3, fast_mem);
2875     io_phi->init_req(3, io);
2876     res_phi->init_req(3, fast_res);
2877   }
2878   transform_later(r);
2879   transform_later(mem_phi);
2880   transform_later(io_phi);
2881   transform_later(res_phi);
2882 
2883   // Do not let stores that initialize this buffer be reordered with a subsequent
2884   // store that would make this buffer accessible by other threads.
2885   MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot);
2886   transform_later(mb);
2887   mb->init_req(TypeFunc::Memory, mem_phi);
2888   mb->init_req(TypeFunc::Control, r);
2889   r = new ProjNode(mb, TypeFunc::Control);
2890   transform_later(r);
2891   mem_phi = new ProjNode(mb, TypeFunc::Memory);
2892   transform_later(mem_phi);
2893 
2894   assert(projs->nb_resproj == 1, "unexpected number of results");
2895   _igvn.replace_in_uses(projs->fallthrough_catchproj, r);
2896   _igvn.replace_in_uses(projs->fallthrough_memproj, mem_phi);
2897   _igvn.replace_in_uses(projs->fallthrough_ioproj, io_phi);
2898   _igvn.replace_in_uses(projs->resproj[0], res_phi);
2899   _igvn.replace_in_uses(projs->catchall_catchproj, ex_r);
2900   _igvn.replace_in_uses(projs->catchall_memproj, ex_mem_phi);
2901   _igvn.replace_in_uses(projs->catchall_ioproj, ex_io_phi);
2902   // The CatchNode should not use the ex_io_phi. Re-connect it to the catchall_ioproj.
2903   Node* cn = projs->fallthrough_catchproj->in(0);
2904   _igvn.replace_input_of(cn, 1, projs->catchall_ioproj);
2905 
2906   _igvn.replace_node(ctl, projs->fallthrough_catchproj);
2907   _igvn.replace_node(mem, projs->fallthrough_memproj);
2908   _igvn.replace_node(io, projs->fallthrough_ioproj);
2909   _igvn.replace_node(res, projs->resproj[0]);
2910   _igvn.replace_node(ex_ctl, projs->catchall_catchproj);
2911   _igvn.replace_node(ex_mem, projs->catchall_memproj);
2912   _igvn.replace_node(ex_io, projs->catchall_ioproj);
2913  }
2914 
2915 void PhaseMacroExpand::expand_subtypecheck_node(SubTypeCheckNode *check) {
2916   assert(check->in(SubTypeCheckNode::Control) == nullptr, "should be pinned");
2917   Node* bol = check->unique_out();
2918   Node* obj_or_subklass = check->in(SubTypeCheckNode::ObjOrSubKlass);
2919   Node* superklass = check->in(SubTypeCheckNode::SuperKlass);
2920   assert(bol->is_Bool() && bol->as_Bool()->_test._test == BoolTest::ne, "unexpected bool node");
2921 
2922   for (DUIterator_Last imin, i = bol->last_outs(imin); i >= imin; --i) {
2923     Node* iff = bol->last_out(i);
2924     assert(iff->is_If(), "where's the if?");
2925 
2926     if (iff->in(0)->is_top()) {
2927       _igvn.replace_input_of(iff, 1, C->top());
2928       continue;
2929     }
2930 
2931     IfTrueNode* iftrue = iff->as_If()->true_proj();
2932     IfFalseNode* iffalse = iff->as_If()->false_proj();
2933     Node* ctrl = iff->in(0);
2934 
2935     Node* subklass = nullptr;
2936     if (_igvn.type(obj_or_subklass)->isa_klassptr()) {
2937       subklass = obj_or_subklass;
2938     } else {
2939       Node* k_adr = basic_plus_adr(obj_or_subklass, oopDesc::klass_offset_in_bytes());
2940       subklass = _igvn.transform(LoadKlassNode::make(_igvn, C->immutable_memory(), k_adr, TypeInstPtr::KLASS, TypeInstKlassPtr::OBJECT));
2941     }
2942 
2943     Node* not_subtype_ctrl = Phase::gen_subtype_check(subklass, superklass, &ctrl, nullptr, _igvn, check->method(), check->bci());
2944 
2945     _igvn.replace_input_of(iff, 0, C->top());
2946     _igvn.replace_node(iftrue, not_subtype_ctrl);
2947     _igvn.replace_node(iffalse, ctrl);
2948   }
2949   _igvn.replace_node(check, C->top());
2950 }
2951 
2952 // FlatArrayCheckNode (array1 array2 ...) is expanded into:
2953 //
2954 // long mark = array1.mark | array2.mark | ...;
2955 // long locked_bit = markWord::unlocked_value & array1.mark & array2.mark & ...;
2956 // if (locked_bit == 0) {
2957 //   // One array is locked, load prototype header from the klass
2958 //   mark = array1.klass.proto | array2.klass.proto | ...
2959 // }
2960 // if ((mark & markWord::flat_array_bit_in_place) == 0) {
2961 //    ...
2962 // }
2963 void PhaseMacroExpand::expand_flatarraycheck_node(FlatArrayCheckNode* check) {
2964   bool array_inputs = _igvn.type(check->in(FlatArrayCheckNode::ArrayOrKlass))->isa_oopptr() != nullptr;
2965   if (array_inputs) {
2966     Node* mark = MakeConX(0);
2967     Node* locked_bit = MakeConX(markWord::unlocked_value);
2968     Node* mem = check->in(FlatArrayCheckNode::Memory);
2969     for (uint i = FlatArrayCheckNode::ArrayOrKlass; i < check->req(); ++i) {
2970       Node* ary = check->in(i);
2971       const TypeOopPtr* t = _igvn.type(ary)->isa_oopptr();
2972       assert(t != nullptr, "Mixing array and klass inputs");
2973       assert(!t->is_flat() && !t->is_not_flat(), "Should have been optimized out");
2974       Node* mark_adr = basic_plus_adr(ary, oopDesc::mark_offset_in_bytes());
2975       Node* mark_load = _igvn.transform(LoadNode::make(_igvn, nullptr, mem, mark_adr, mark_adr->bottom_type()->is_ptr(), TypeX_X, TypeX_X->basic_type(), MemNode::unordered));
2976       mark = _igvn.transform(new OrXNode(mark, mark_load));
2977       locked_bit = _igvn.transform(new AndXNode(locked_bit, mark_load));
2978     }
2979     assert(!mark->is_Con(), "Should have been optimized out");
2980     Node* cmp = _igvn.transform(new CmpXNode(locked_bit, MakeConX(0)));
2981     Node* is_unlocked = _igvn.transform(new BoolNode(cmp, BoolTest::ne));
2982 
2983     // BoolNode might be shared, replace each if user
2984     Node* old_bol = check->unique_out();
2985     assert(old_bol->is_Bool() && old_bol->as_Bool()->_test._test == BoolTest::ne, "unexpected condition");
2986     for (DUIterator_Last imin, i = old_bol->last_outs(imin); i >= imin; --i) {
2987       IfNode* old_iff = old_bol->last_out(i)->as_If();
2988       Node* ctrl = old_iff->in(0);
2989       RegionNode* region = new RegionNode(3);
2990       Node* mark_phi = new PhiNode(region, TypeX_X);
2991 
2992       // Check if array is unlocked
2993       IfNode* iff = _igvn.transform(new IfNode(ctrl, is_unlocked, PROB_MAX, COUNT_UNKNOWN))->as_If();
2994 
2995       // Unlocked: Use bits from mark word
2996       region->init_req(1, _igvn.transform(new IfTrueNode(iff)));
2997       mark_phi->init_req(1, mark);
2998 
2999       // Locked: Load prototype header from klass
3000       ctrl = _igvn.transform(new IfFalseNode(iff));
3001       Node* proto = MakeConX(0);
3002       for (uint i = FlatArrayCheckNode::ArrayOrKlass; i < check->req(); ++i) {
3003         Node* ary = check->in(i);
3004         // Make loads control dependent to make sure they are only executed if array is locked
3005         Node* klass_adr = basic_plus_adr(ary, oopDesc::klass_offset_in_bytes());
3006         Node* klass = _igvn.transform(LoadKlassNode::make(_igvn, C->immutable_memory(), klass_adr, TypeInstPtr::KLASS, TypeInstKlassPtr::OBJECT));
3007         Node* proto_adr = basic_plus_adr(klass, in_bytes(Klass::prototype_header_offset()));
3008         Node* proto_load = _igvn.transform(LoadNode::make(_igvn, ctrl, C->immutable_memory(), proto_adr, proto_adr->bottom_type()->is_ptr(), TypeX_X, TypeX_X->basic_type(), MemNode::unordered));
3009         proto = _igvn.transform(new OrXNode(proto, proto_load));
3010       }
3011       region->init_req(2, ctrl);
3012       mark_phi->init_req(2, proto);
3013 
3014       // Check if flat array bits are set
3015       Node* mask = MakeConX(markWord::flat_array_bit_in_place);
3016       Node* masked = _igvn.transform(new AndXNode(_igvn.transform(mark_phi), mask));
3017       cmp = _igvn.transform(new CmpXNode(masked, MakeConX(0)));
3018       Node* is_not_flat = _igvn.transform(new BoolNode(cmp, BoolTest::eq));
3019 
3020       ctrl = _igvn.transform(region);
3021       iff = _igvn.transform(new IfNode(ctrl, is_not_flat, PROB_MAX, COUNT_UNKNOWN))->as_If();
3022       _igvn.replace_node(old_iff, iff);
3023     }
3024     _igvn.replace_node(check, C->top());
3025   } else {
3026     // Fall back to layout helper check
3027     Node* lhs = intcon(0);
3028     for (uint i = FlatArrayCheckNode::ArrayOrKlass; i < check->req(); ++i) {
3029       Node* array_or_klass = check->in(i);
3030       Node* klass = nullptr;
3031       const TypePtr* t = _igvn.type(array_or_klass)->is_ptr();
3032       assert(!t->is_flat() && !t->is_not_flat(), "Should have been optimized out");
3033       if (t->isa_oopptr() != nullptr) {
3034         Node* klass_adr = basic_plus_adr(array_or_klass, oopDesc::klass_offset_in_bytes());
3035         klass = transform_later(LoadKlassNode::make(_igvn, C->immutable_memory(), klass_adr, TypeInstPtr::KLASS, TypeInstKlassPtr::OBJECT));
3036       } else {
3037         assert(t->isa_klassptr(), "Unexpected input type");
3038         klass = array_or_klass;
3039       }
3040       Node* lh_addr = basic_plus_adr(klass, in_bytes(Klass::layout_helper_offset()));
3041       Node* lh_val = _igvn.transform(LoadNode::make(_igvn, nullptr, C->immutable_memory(), lh_addr, lh_addr->bottom_type()->is_ptr(), TypeInt::INT, T_INT, MemNode::unordered));
3042       lhs = _igvn.transform(new OrINode(lhs, lh_val));
3043     }
3044     Node* masked = transform_later(new AndINode(lhs, intcon(Klass::_lh_array_tag_flat_value_bit_inplace)));
3045     Node* cmp = transform_later(new CmpINode(masked, intcon(0)));
3046     Node* bol = transform_later(new BoolNode(cmp, BoolTest::eq));
3047     Node* m2b = transform_later(new Conv2BNode(masked));
3048     // The matcher expects the input to If/CMove nodes to be produced by a Bool(CmpI..)
3049     // pattern, but the input to other potential users (e.g. Phi) to be some
3050     // other pattern (e.g. a Conv2B node, possibly idealized as a CMoveI).
3051     Node* old_bol = check->unique_out();
3052     for (DUIterator_Last imin, i = old_bol->last_outs(imin); i >= imin; --i) {
3053       Node* user = old_bol->last_out(i);
3054       for (uint j = 0; j < user->req(); j++) {
3055         Node* n = user->in(j);
3056         if (n == old_bol) {
3057           _igvn.replace_input_of(user, j, (user->is_If() || user->is_CMove()) ? bol : m2b);
3058         }
3059       }
3060     }
3061     _igvn.replace_node(check, C->top());
3062   }
3063 }
3064 
3065 // Perform refining of strip mined loop nodes in the macro nodes list.
3066 void PhaseMacroExpand::refine_strip_mined_loop_macro_nodes() {
3067    for (int i = C->macro_count(); i > 0; i--) {
3068     Node* n = C->macro_node(i - 1);
3069     if (n->is_OuterStripMinedLoop()) {
3070       n->as_OuterStripMinedLoop()->adjust_strip_mined_loop(&_igvn);
3071     }
3072   }
3073 }
3074 
3075 //---------------------------eliminate_macro_nodes----------------------
3076 // Eliminate scalar replaced allocations and associated locks.
3077 void PhaseMacroExpand::eliminate_macro_nodes(bool eliminate_locks) {
3078   if (C->macro_count() == 0) {
3079     return;
3080   }
3081 
3082   if (StressMacroElimination) {
3083     C->shuffle_macro_nodes();
3084   }
3085   NOT_PRODUCT(int membar_before = count_MemBar(C);)
3086 
3087   int iteration = 0;
3088   while (C->macro_count() > 0) {
3089     if (iteration++ > 100) {
3090       assert(false, "Too slow convergence of macro elimination");
3091       break;
3092     }
3093 
3094     // Postpone lock elimination to after EA when most allocations are eliminated
3095     // because they might block lock elimination if their escape state isn't
3096     // determined yet and we only got one chance at eliminating the lock.
3097     if (eliminate_locks) {
3098       // Before elimination may re-mark (change to Nested or NonEscObj)
3099       // all associated (same box and obj) lock and unlock nodes.
3100       int cnt = C->macro_count();
3101       for (int i=0; i < cnt; i++) {
3102         Node *n = C->macro_node(i);
3103         if (n->is_AbstractLock()) { // Lock and Unlock nodes
3104           mark_eliminated_locking_nodes(n->as_AbstractLock());
3105         }
3106       }
3107       // Re-marking may break consistency of Coarsened locks.
3108       if (!C->coarsened_locks_consistent()) {
3109         return; // recompile without Coarsened locks if broken
3110       } else {
3111         // After coarsened locks are eliminated locking regions
3112         // become unbalanced. We should not execute any more
3113         // locks elimination optimizations on them.
3114         C->mark_unbalanced_boxes();
3115       }
3116     }
3117 
3118     bool progress = false;
3119     for (int i = C->macro_count(); i > 0; i = MIN2(i - 1, C->macro_count())) { // more than 1 element can be eliminated at once
3120       Node* n = C->macro_node(i - 1);
3121       bool success = false;
3122       DEBUG_ONLY(int old_macro_count = C->macro_count();)
3123       switch (n->class_id()) {
3124       case Node::Class_Allocate:
3125       case Node::Class_AllocateArray:
3126         success = eliminate_allocate_node(n->as_Allocate());
3127 #ifndef PRODUCT
3128         if (success && PrintOptoStatistics) {
3129           AtomicAccess::inc(&PhaseMacroExpand::_objs_scalar_replaced_counter);
3130         }
3131 #endif
3132         break;
3133       case Node::Class_CallStaticJava: {
3134         CallStaticJavaNode* call = n->as_CallStaticJava();
3135         if (!call->method()->is_method_handle_intrinsic()) {
3136           success = eliminate_boxing_node(n->as_CallStaticJava());
3137         }
3138         break;
3139       }
3140       case Node::Class_Lock:
3141       case Node::Class_Unlock:
3142         if (eliminate_locks) {
3143           success = eliminate_locking_node(n->as_AbstractLock());
3144 #ifndef PRODUCT
3145           if (success && PrintOptoStatistics) {
3146             AtomicAccess::inc(&PhaseMacroExpand::_monitor_objects_removed_counter);
3147           }
3148 #endif
3149         }
3150         break;
3151       case Node::Class_ArrayCopy:
3152         break;
3153       case Node::Class_OuterStripMinedLoop:
3154         break;
3155       case Node::Class_SubTypeCheck:
3156         break;
3157       case Node::Class_Opaque1:
3158         break;
3159       case Node::Class_FlatArrayCheck:
3160         break;
3161       default:
3162         assert(n->Opcode() == Op_LoopLimit ||
3163                n->Opcode() == Op_ModD ||
3164                n->Opcode() == Op_ModF ||
3165                n->is_OpaqueNotNull()       ||
3166                n->is_OpaqueInitializedAssertionPredicate() ||
3167                n->Opcode() == Op_MaxL      ||
3168                n->Opcode() == Op_MinL      ||
3169                BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(n),
3170                "unknown node type in macro list");
3171       }
3172       assert(success == (C->macro_count() < old_macro_count), "elimination reduces macro count");
3173       progress = progress || success;
3174       if (success) {
3175         C->print_method(PHASE_AFTER_MACRO_ELIMINATION_STEP, 5, n);
3176       }
3177     }
3178 
3179     // Ensure the graph after PhaseMacroExpand::eliminate_macro_nodes is canonical (no igvn
3180     // transformation is pending). If an allocation is used only in safepoints, elimination of
3181     // other macro nodes can remove all these safepoints, allowing the allocation to be removed.
3182     // Hence after igvn we retry removing macro nodes if some progress that has been made in this
3183     // iteration.
3184     _igvn.set_delay_transform(false);
3185     _igvn.optimize();
3186     if (C->failing()) {
3187       return;
3188     }
3189     _igvn.set_delay_transform(true);
3190 
3191     if (!progress) {
3192       break;
3193     }
3194   }
3195 #ifndef PRODUCT
3196   if (PrintOptoStatistics) {
3197     int membar_after = count_MemBar(C);
3198     AtomicAccess::add(&PhaseMacroExpand::_memory_barriers_removed_counter, membar_before - membar_after);
3199   }
3200 #endif
3201 }
3202 
3203 void PhaseMacroExpand::eliminate_opaque_looplimit_macro_nodes() {
3204   if (C->macro_count() == 0) {
3205     return;
3206   }
3207   refine_strip_mined_loop_macro_nodes();
3208   // Eliminate Opaque and LoopLimit nodes. Do it after all loop optimizations.
3209   bool progress = true;
3210   while (progress) {
3211     progress = false;
3212     for (int i = C->macro_count(); i > 0; i--) {
3213       Node* n = C->macro_node(i-1);
3214       bool success = false;
3215       DEBUG_ONLY(int old_macro_count = C->macro_count();)
3216       if (n->Opcode() == Op_LoopLimit) {
3217         // Remove it from macro list and put on IGVN worklist to optimize.
3218         C->remove_macro_node(n);
3219         _igvn._worklist.push(n);
3220         success = true;
3221       } else if (n->Opcode() == Op_CallStaticJava) {
3222         CallStaticJavaNode* call = n->as_CallStaticJava();
3223         if (!call->method()->is_method_handle_intrinsic()) {
3224           // Remove it from macro list and put on IGVN worklist to optimize.
3225           C->remove_macro_node(n);
3226           _igvn._worklist.push(n);
3227           success = true;
3228         }
3229       } else if (n->is_Opaque1()) {
3230         _igvn.replace_node(n, n->in(1));
3231         success = true;
3232       } else if (n->is_OpaqueNotNull()) {
3233         // Tests with OpaqueNotNull nodes are implicitly known to be true. Replace the node with true. In debug builds,
3234         // we leave the test in the graph to have an additional sanity check at runtime. If the test fails (i.e. a bug),
3235         // we will execute a Halt node.
3236 #ifdef ASSERT
3237         _igvn.replace_node(n, n->in(1));
3238 #else
3239         _igvn.replace_node(n, _igvn.intcon(1));
3240 #endif
3241         success = true;
3242       } else if (n->is_OpaqueInitializedAssertionPredicate()) {
3243           // Initialized Assertion Predicates must always evaluate to true. Therefore, we get rid of them in product
3244           // builds as they are useless. In debug builds we keep them as additional verification code. Even though
3245           // loop opts are already over, we want to keep Initialized Assertion Predicates alive as long as possible to
3246           // enable folding of dead control paths within which cast nodes become top after due to impossible types -
3247           // even after loop opts are over. Therefore, we delay the removal of these opaque nodes until now.
3248 #ifdef ASSERT
3249         _igvn.replace_node(n, n->in(1));
3250 #else
3251         _igvn.replace_node(n, _igvn.intcon(1));
3252 #endif // ASSERT
3253       } else if (n->Opcode() == Op_OuterStripMinedLoop) {
3254         C->remove_macro_node(n);
3255         success = true;
3256       } else if (n->Opcode() == Op_MaxL) {
3257         // Since MaxL and MinL are not implemented in the backend, we expand them to
3258         // a CMoveL construct now. At least until here, the type could be computed
3259         // precisely. CMoveL is not so smart, but we can give it at least the best
3260         // type we know abouot n now.
3261         Node* repl = MaxNode::signed_max(n->in(1), n->in(2), _igvn.type(n), _igvn);
3262         _igvn.replace_node(n, repl);
3263         success = true;
3264       } else if (n->Opcode() == Op_MinL) {
3265         Node* repl = MaxNode::signed_min(n->in(1), n->in(2), _igvn.type(n), _igvn);
3266         _igvn.replace_node(n, repl);
3267         success = true;
3268       }
3269       assert(!success || (C->macro_count() == (old_macro_count - 1)), "elimination must have deleted one node from macro list");
3270       progress = progress || success;
3271       if (success) {
3272         C->print_method(PHASE_AFTER_MACRO_ELIMINATION_STEP, 5, n);
3273       }
3274     }
3275   }
3276 }
3277 
3278 //------------------------------expand_macro_nodes----------------------
3279 //  Returns true if a failure occurred.
3280 bool PhaseMacroExpand::expand_macro_nodes() {
3281   if (StressMacroExpansion) {
3282     C->shuffle_macro_nodes();
3283   }
3284 
3285   // Clean up the graph so we're less likely to hit the maximum node
3286   // limit
3287   _igvn.set_delay_transform(false);
3288   _igvn.optimize();
3289   if (C->failing())  return true;
3290   _igvn.set_delay_transform(true);
3291 
3292 
3293   // Because we run IGVN after each expansion, some macro nodes may go
3294   // dead and be removed from the list as we iterate over it. Move
3295   // Allocate nodes (processed in a second pass) at the beginning of
3296   // the list and then iterate from the last element of the list until
3297   // an Allocate node is seen. This is robust to random deletion in
3298   // the list due to nodes going dead.
3299   C->sort_macro_nodes();
3300 
3301   // expand arraycopy "macro" nodes first
3302   // For ReduceBulkZeroing, we must first process all arraycopy nodes
3303   // before the allocate nodes are expanded.
3304   while (C->macro_count() > 0) {
3305     int macro_count = C->macro_count();
3306     Node * n = C->macro_node(macro_count-1);
3307     assert(n->is_macro(), "only macro nodes expected here");
3308     if (_igvn.type(n) == Type::TOP || (n->in(0) != nullptr && n->in(0)->is_top())) {
3309       // node is unreachable, so don't try to expand it
3310       C->remove_macro_node(n);
3311       continue;
3312     }
3313     if (n->is_Allocate()) {
3314       break;
3315     }
3316     // Make sure expansion will not cause node limit to be exceeded.
3317     // Worst case is a macro node gets expanded into about 200 nodes.
3318     // Allow 50% more for optimization.
3319     if (C->check_node_count(300, "out of nodes before macro expansion")) {
3320       return true;
3321     }
3322 
3323     DEBUG_ONLY(int old_macro_count = C->macro_count();)
3324     switch (n->class_id()) {
3325     case Node::Class_Lock:
3326       expand_lock_node(n->as_Lock());
3327       break;
3328     case Node::Class_Unlock:
3329       expand_unlock_node(n->as_Unlock());
3330       break;
3331     case Node::Class_ArrayCopy:
3332       expand_arraycopy_node(n->as_ArrayCopy());
3333       break;
3334     case Node::Class_SubTypeCheck:
3335       expand_subtypecheck_node(n->as_SubTypeCheck());
3336       break;
3337     case Node::Class_CallStaticJava:
3338       expand_mh_intrinsic_return(n->as_CallStaticJava());
3339       C->remove_macro_node(n);
3340       break;
3341     case Node::Class_FlatArrayCheck:
3342       expand_flatarraycheck_node(n->as_FlatArrayCheck());
3343       break;
3344     default:
3345       switch (n->Opcode()) {
3346       case Op_ModD:
3347       case Op_ModF: {
3348         CallNode* mod_macro = n->as_Call();
3349         CallNode* call = new CallLeafPureNode(mod_macro->tf(), mod_macro->entry_point(), mod_macro->_name);
3350         call->init_req(TypeFunc::Control, mod_macro->in(TypeFunc::Control));
3351         call->init_req(TypeFunc::I_O, C->top());
3352         call->init_req(TypeFunc::Memory, C->top());
3353         call->init_req(TypeFunc::ReturnAdr, C->top());
3354         call->init_req(TypeFunc::FramePtr, C->top());
3355         for (unsigned int i = 0; i < mod_macro->tf()->domain_cc()->cnt() - TypeFunc::Parms; i++) {
3356           call->init_req(TypeFunc::Parms + i, mod_macro->in(TypeFunc::Parms + i));
3357         }
3358         _igvn.replace_node(mod_macro, call);
3359         transform_later(call);
3360         break;
3361       }
3362       default:
3363         assert(false, "unknown node type in macro list");
3364       }
3365     }
3366     assert(C->macro_count() == (old_macro_count - 1), "expansion must have deleted one node from macro list");
3367     if (C->failing())  return true;
3368     C->print_method(PHASE_AFTER_MACRO_EXPANSION_STEP, 5, n);
3369 
3370     // Clean up the graph so we're less likely to hit the maximum node
3371     // limit
3372     _igvn.set_delay_transform(false);
3373     _igvn.optimize();
3374     if (C->failing())  return true;
3375     _igvn.set_delay_transform(true);
3376   }
3377 
3378   // All nodes except Allocate nodes are expanded now. There could be
3379   // new optimization opportunities (such as folding newly created
3380   // load from a just allocated object). Run IGVN.
3381 
3382   // expand "macro" nodes
3383   // nodes are removed from the macro list as they are processed
3384   while (C->macro_count() > 0) {
3385     int macro_count = C->macro_count();
3386     Node * n = C->macro_node(macro_count-1);
3387     assert(n->is_macro(), "only macro nodes expected here");
3388     if (_igvn.type(n) == Type::TOP || (n->in(0) != nullptr && n->in(0)->is_top())) {
3389       // node is unreachable, so don't try to expand it
3390       C->remove_macro_node(n);
3391       continue;
3392     }
3393     // Make sure expansion will not cause node limit to be exceeded.
3394     // Worst case is a macro node gets expanded into about 200 nodes.
3395     // Allow 50% more for optimization.
3396     if (C->check_node_count(300, "out of nodes before macro expansion")) {
3397       return true;
3398     }
3399     switch (n->class_id()) {
3400     case Node::Class_Allocate:
3401       expand_allocate(n->as_Allocate());
3402       break;
3403     case Node::Class_AllocateArray:
3404       expand_allocate_array(n->as_AllocateArray());
3405       break;
3406     default:
3407       assert(false, "unknown node type in macro list");
3408     }
3409     assert(C->macro_count() < macro_count, "must have deleted a node from macro list");
3410     if (C->failing())  return true;
3411     C->print_method(PHASE_AFTER_MACRO_EXPANSION_STEP, 5, n);
3412 
3413     // Clean up the graph so we're less likely to hit the maximum node
3414     // limit
3415     _igvn.set_delay_transform(false);
3416     _igvn.optimize();
3417     if (C->failing())  return true;
3418     _igvn.set_delay_transform(true);
3419   }
3420 
3421   _igvn.set_delay_transform(false);
3422   return false;
3423 }
3424 
3425 #ifndef PRODUCT
3426 int PhaseMacroExpand::_objs_scalar_replaced_counter = 0;
3427 int PhaseMacroExpand::_monitor_objects_removed_counter = 0;
3428 int PhaseMacroExpand::_GC_barriers_removed_counter = 0;
3429 int PhaseMacroExpand::_memory_barriers_removed_counter = 0;
3430 
3431 void PhaseMacroExpand::print_statistics() {
3432   tty->print("Objects scalar replaced = %d, ", AtomicAccess::load(&_objs_scalar_replaced_counter));
3433   tty->print("Monitor objects removed = %d, ", AtomicAccess::load(&_monitor_objects_removed_counter));
3434   tty->print("GC barriers removed = %d, ", AtomicAccess::load(&_GC_barriers_removed_counter));
3435   tty->print_cr("Memory barriers removed = %d", AtomicAccess::load(&_memory_barriers_removed_counter));
3436 }
3437 
3438 int PhaseMacroExpand::count_MemBar(Compile *C) {
3439   if (!PrintOptoStatistics) {
3440     return 0;
3441   }
3442   Unique_Node_List ideal_nodes;
3443   int total = 0;
3444   ideal_nodes.map(C->live_nodes(), nullptr);
3445   ideal_nodes.push(C->root());
3446   for (uint next = 0; next < ideal_nodes.size(); ++next) {
3447     Node* n = ideal_nodes.at(next);
3448     if (n->is_MemBar()) {
3449       total++;
3450     }
3451     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3452       Node* m = n->fast_out(i);
3453       ideal_nodes.push(m);
3454     }
3455   }
3456   return total;
3457 }
3458 #endif