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 "compiler/compileLog.hpp"
  26 #include "gc/shared/collectedHeap.inline.hpp"
  27 #include "gc/shared/tlab_globals.hpp"
  28 #include "libadt/vectset.hpp"
  29 #include "memory/universe.hpp"
  30 #include "opto/addnode.hpp"
  31 #include "opto/arraycopynode.hpp"
  32 #include "opto/callnode.hpp"
  33 #include "opto/castnode.hpp"
  34 #include "opto/cfgnode.hpp"
  35 #include "opto/compile.hpp"
  36 #include "opto/convertnode.hpp"
  37 #include "opto/graphKit.hpp"
  38 #include "opto/intrinsicnode.hpp"
  39 #include "opto/locknode.hpp"
  40 #include "opto/loopnode.hpp"
  41 #include "opto/macro.hpp"
  42 #include "opto/memnode.hpp"
  43 #include "opto/narrowptrnode.hpp"
  44 #include "opto/node.hpp"
  45 #include "opto/opaquenode.hpp"
  46 #include "opto/phaseX.hpp"
  47 #include "opto/rootnode.hpp"
  48 #include "opto/runtime.hpp"
  49 #include "opto/subnode.hpp"
  50 #include "opto/subtypenode.hpp"
  51 #include "opto/type.hpp"
  52 #include "prims/jvmtiExport.hpp"
  53 #include "runtime/continuation.hpp"
  54 #include "runtime/sharedRuntime.hpp"
  55 #include "utilities/macros.hpp"
  56 #include "utilities/powerOfTwo.hpp"
  57 #if INCLUDE_G1GC
  58 #include "gc/g1/g1ThreadLocalData.hpp"
  59 #endif // INCLUDE_G1GC
  60 
  61 
  62 //
  63 // Replace any references to "oldref" in inputs to "use" with "newref".
  64 // Returns the number of replacements made.
  65 //
  66 int PhaseMacroExpand::replace_input(Node *use, Node *oldref, Node *newref) {
  67   int nreplacements = 0;
  68   uint req = use->req();
  69   for (uint j = 0; j < use->len(); j++) {
  70     Node *uin = use->in(j);
  71     if (uin == oldref) {
  72       if (j < req)
  73         use->set_req(j, newref);
  74       else
  75         use->set_prec(j, newref);
  76       nreplacements++;
  77     } else if (j >= req && uin == nullptr) {
  78       break;
  79     }
  80   }
  81   return nreplacements;
  82 }
  83 
  84 void PhaseMacroExpand::migrate_outs(Node *old, Node *target) {
  85   assert(old != nullptr, "sanity");
  86   for (DUIterator_Fast imax, i = old->fast_outs(imax); i < imax; i++) {
  87     Node* use = old->fast_out(i);
  88     _igvn.rehash_node_delayed(use);
  89     imax -= replace_input(use, old, target);
  90     // back up iterator
  91     --i;
  92   }
  93   assert(old->outcnt() == 0, "all uses must be deleted");
  94 }
  95 
  96 Node* PhaseMacroExpand::opt_bits_test(Node* ctrl, Node* region, int edge, Node* word) {
  97   Node* cmp = word;
  98   Node* bol = transform_later(new BoolNode(cmp, BoolTest::ne));
  99   IfNode* iff = new IfNode( ctrl, bol, PROB_MIN, COUNT_UNKNOWN );
 100   transform_later(iff);
 101 
 102   // Fast path taken.
 103   Node *fast_taken = transform_later(new IfFalseNode(iff));
 104 
 105   // Fast path not-taken, i.e. slow path
 106   Node *slow_taken = transform_later(new IfTrueNode(iff));
 107 
 108     region->init_req(edge, fast_taken); // Capture fast-control
 109     return slow_taken;
 110 }
 111 
 112 //--------------------copy_predefined_input_for_runtime_call--------------------
 113 void PhaseMacroExpand::copy_predefined_input_for_runtime_call(Node * ctrl, CallNode* oldcall, CallNode* call) {
 114   // Set fixed predefined input arguments
 115   call->init_req( TypeFunc::Control, ctrl );
 116   call->init_req( TypeFunc::I_O    , oldcall->in( TypeFunc::I_O) );
 117   call->init_req( TypeFunc::Memory , oldcall->in( TypeFunc::Memory ) ); // ?????
 118   call->init_req( TypeFunc::ReturnAdr, oldcall->in( TypeFunc::ReturnAdr ) );
 119   call->init_req( TypeFunc::FramePtr, oldcall->in( TypeFunc::FramePtr ) );
 120 }
 121 
 122 //------------------------------make_slow_call---------------------------------
 123 CallNode* PhaseMacroExpand::make_slow_call(CallNode *oldcall, const TypeFunc* slow_call_type,
 124                                            address slow_call, const char* leaf_name, Node* slow_path,
 125                                            Node* parm0, Node* parm1, Node* parm2) {
 126 
 127   // Slow-path call
 128  CallNode *call = leaf_name
 129    ? (CallNode*)new CallLeafNode      ( slow_call_type, slow_call, leaf_name, TypeRawPtr::BOTTOM )
 130    : (CallNode*)new CallStaticJavaNode( slow_call_type, slow_call, OptoRuntime::stub_name(slow_call), TypeRawPtr::BOTTOM );
 131 
 132   // Slow path call has no side-effects, uses few values
 133   copy_predefined_input_for_runtime_call(slow_path, oldcall, call );
 134   if (parm0 != nullptr)  call->init_req(TypeFunc::Parms+0, parm0);
 135   if (parm1 != nullptr)  call->init_req(TypeFunc::Parms+1, parm1);
 136   if (parm2 != nullptr)  call->init_req(TypeFunc::Parms+2, parm2);
 137   call->copy_call_debug_info(&_igvn, oldcall);
 138   call->set_cnt(PROB_UNLIKELY_MAG(4));  // Same effect as RC_UNCOMMON.
 139   _igvn.replace_node(oldcall, call);
 140   transform_later(call);
 141 
 142   return call;
 143 }
 144 
 145 void PhaseMacroExpand::eliminate_gc_barrier(Node* p2x) {
 146   BarrierSetC2 *bs = BarrierSet::barrier_set()->barrier_set_c2();
 147   bs->eliminate_gc_barrier(this, p2x);
 148 #ifndef PRODUCT
 149   if (PrintOptoStatistics) {
 150     Atomic::inc(&PhaseMacroExpand::_GC_barriers_removed_counter);
 151   }
 152 #endif
 153 }
 154 
 155 // Search for a memory operation for the specified memory slice.
 156 static Node *scan_mem_chain(Node *mem, int alias_idx, int offset, Node *start_mem, Node *alloc, PhaseGVN *phase) {
 157   Node *orig_mem = mem;
 158   Node *alloc_mem = alloc->as_Allocate()->proj_out_or_null(TypeFunc::Memory, /*io_use:*/false);
 159   assert(alloc_mem != nullptr, "Allocation without a memory projection.");
 160   const TypeOopPtr *tinst = phase->C->get_adr_type(alias_idx)->isa_oopptr();
 161   while (true) {
 162     if (mem == alloc_mem || mem == start_mem ) {
 163       return mem;  // hit one of our sentinels
 164     } else if (mem->is_MergeMem()) {
 165       mem = mem->as_MergeMem()->memory_at(alias_idx);
 166     } else if (mem->is_Proj() && mem->as_Proj()->_con == TypeFunc::Memory) {
 167       Node *in = mem->in(0);
 168       // we can safely skip over safepoints, calls, locks and membars because we
 169       // already know that the object is safe to eliminate.
 170       if (in->is_Initialize() && in->as_Initialize()->allocation() == alloc) {
 171         return in;
 172       } else if (in->is_Call()) {
 173         CallNode *call = in->as_Call();
 174         if (call->may_modify(tinst, phase)) {
 175           assert(call->is_ArrayCopy(), "ArrayCopy is the only call node that doesn't make allocation escape");
 176           if (call->as_ArrayCopy()->modifies(offset, offset, phase, false)) {
 177             return in;
 178           }
 179         }
 180         mem = in->in(TypeFunc::Memory);
 181       } else if (in->is_MemBar()) {
 182         ArrayCopyNode* ac = nullptr;
 183         if (ArrayCopyNode::may_modify(tinst, in->as_MemBar(), phase, ac)) {
 184           if (ac != nullptr) {
 185             assert(ac->is_clonebasic(), "Only basic clone is a non escaping clone");
 186             return ac;
 187           }
 188         }
 189         mem = in->in(TypeFunc::Memory);
 190       } else {
 191 #ifdef ASSERT
 192         in->dump();
 193         mem->dump();
 194         assert(false, "unexpected projection");
 195 #endif
 196       }
 197     } else if (mem->is_Store()) {
 198       const TypePtr* atype = mem->as_Store()->adr_type();
 199       int adr_idx = phase->C->get_alias_index(atype);
 200       if (adr_idx == alias_idx) {
 201         assert(atype->isa_oopptr(), "address type must be oopptr");
 202         int adr_offset = atype->offset();
 203         uint adr_iid = atype->is_oopptr()->instance_id();
 204         // Array elements references have the same alias_idx
 205         // but different offset and different instance_id.
 206         if (adr_offset == offset && adr_iid == alloc->_idx) {
 207           return mem;
 208         }
 209       } else {
 210         assert(adr_idx == Compile::AliasIdxRaw, "address must match or be raw");
 211       }
 212       mem = mem->in(MemNode::Memory);
 213     } else if (mem->is_ClearArray()) {
 214       if (!ClearArrayNode::step_through(&mem, alloc->_idx, phase)) {
 215         // Can not bypass initialization of the instance
 216         // we are looking.
 217         DEBUG_ONLY(intptr_t offset;)
 218         assert(alloc == AllocateNode::Ideal_allocation(mem->in(3), phase, offset), "sanity");
 219         InitializeNode* init = alloc->as_Allocate()->initialization();
 220         // We are looking for stored value, return Initialize node
 221         // or memory edge from Allocate node.
 222         if (init != nullptr) {
 223           return init;
 224         } else {
 225           return alloc->in(TypeFunc::Memory); // It will produce zero value (see callers).
 226         }
 227       }
 228       // Otherwise skip it (the call updated 'mem' value).
 229     } else if (mem->Opcode() == Op_SCMemProj) {
 230       mem = mem->in(0);
 231       Node* adr = nullptr;
 232       if (mem->is_LoadStore()) {
 233         adr = mem->in(MemNode::Address);
 234       } else {
 235         assert(mem->Opcode() == Op_EncodeISOArray ||
 236                mem->Opcode() == Op_StrCompressedCopy, "sanity");
 237         adr = mem->in(3); // Destination array
 238       }
 239       const TypePtr* atype = adr->bottom_type()->is_ptr();
 240       int adr_idx = phase->C->get_alias_index(atype);
 241       if (adr_idx == alias_idx) {
 242         DEBUG_ONLY(mem->dump();)
 243         assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
 244         return nullptr;
 245       }
 246       mem = mem->in(MemNode::Memory);
 247    } else if (mem->Opcode() == Op_StrInflatedCopy) {
 248       Node* adr = mem->in(3); // Destination array
 249       const TypePtr* atype = adr->bottom_type()->is_ptr();
 250       int adr_idx = phase->C->get_alias_index(atype);
 251       if (adr_idx == alias_idx) {
 252         DEBUG_ONLY(mem->dump();)
 253         assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
 254         return nullptr;
 255       }
 256       mem = mem->in(MemNode::Memory);
 257     } else {
 258       return mem;
 259     }
 260     assert(mem != orig_mem, "dead memory loop");
 261   }
 262 }
 263 
 264 // Generate loads from source of the arraycopy for fields of
 265 // destination needed at a deoptimization point
 266 Node* PhaseMacroExpand::make_arraycopy_load(ArrayCopyNode* ac, intptr_t offset, Node* ctl, Node* mem, BasicType ft, const Type *ftype, AllocateNode *alloc) {
 267   BasicType bt = ft;
 268   const Type *type = ftype;
 269   if (ft == T_NARROWOOP) {
 270     bt = T_OBJECT;
 271     type = ftype->make_oopptr();
 272   }
 273   Node* res = nullptr;
 274   if (ac->is_clonebasic()) {
 275     assert(ac->in(ArrayCopyNode::Src) != ac->in(ArrayCopyNode::Dest), "clone source equals destination");
 276     Node* base = ac->in(ArrayCopyNode::Src);
 277     Node* adr = _igvn.transform(new AddPNode(base, base, _igvn.MakeConX(offset)));
 278     const TypePtr* adr_type = _igvn.type(base)->is_ptr()->add_offset(offset);
 279     MergeMemNode* mergemen = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
 280     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 281     res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemen, adr, adr_type, type, bt);
 282   } else {
 283     if (ac->modifies(offset, offset, &_igvn, true)) {
 284       assert(ac->in(ArrayCopyNode::Dest) == alloc->result_cast(), "arraycopy destination should be allocation's result");
 285       uint shift = exact_log2(type2aelembytes(bt));
 286       Node* src_pos = ac->in(ArrayCopyNode::SrcPos);
 287       Node* dest_pos = ac->in(ArrayCopyNode::DestPos);
 288       const TypeInt* src_pos_t = _igvn.type(src_pos)->is_int();
 289       const TypeInt* dest_pos_t = _igvn.type(dest_pos)->is_int();
 290 
 291       Node* adr = nullptr;
 292       const TypePtr* adr_type = nullptr;
 293       if (src_pos_t->is_con() && dest_pos_t->is_con()) {
 294         intptr_t off = ((src_pos_t->get_con() - dest_pos_t->get_con()) << shift) + offset;
 295         Node* base = ac->in(ArrayCopyNode::Src);
 296         adr = _igvn.transform(new AddPNode(base, base, _igvn.MakeConX(off)));
 297         adr_type = _igvn.type(base)->is_ptr()->add_offset(off);
 298         if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
 299           // Don't emit a new load from src if src == dst but try to get the value from memory instead
 300           return value_from_mem(ac->in(TypeFunc::Memory), ctl, ft, ftype, adr_type->isa_oopptr(), alloc);
 301         }
 302       } else {
 303         Node* diff = _igvn.transform(new SubINode(ac->in(ArrayCopyNode::SrcPos), ac->in(ArrayCopyNode::DestPos)));
 304 #ifdef _LP64
 305         diff = _igvn.transform(new ConvI2LNode(diff));
 306 #endif
 307         diff = _igvn.transform(new LShiftXNode(diff, _igvn.intcon(shift)));
 308 
 309         Node* off = _igvn.transform(new AddXNode(_igvn.MakeConX(offset), diff));
 310         Node* base = ac->in(ArrayCopyNode::Src);
 311         adr = _igvn.transform(new AddPNode(base, base, off));
 312         adr_type = _igvn.type(base)->is_ptr()->add_offset(Type::OffsetBot);
 313         if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
 314           // Non constant offset in the array: we can't statically
 315           // determine the value
 316           return nullptr;
 317         }
 318       }
 319       MergeMemNode* mergemen = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
 320       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 321       res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemen, adr, adr_type, type, bt);
 322     }
 323   }
 324   if (res != nullptr) {
 325     if (ftype->isa_narrowoop()) {
 326       // PhaseMacroExpand::scalar_replacement adds DecodeN nodes
 327       res = _igvn.transform(new EncodePNode(res, ftype));
 328     }
 329     return res;
 330   }
 331   return nullptr;
 332 }
 333 
 334 //
 335 // Given a Memory Phi, compute a value Phi containing the values from stores
 336 // on the input paths.
 337 // Note: this function is recursive, its depth is limited by the "level" argument
 338 // Returns the computed Phi, or null if it cannot compute it.
 339 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) {
 340   assert(mem->is_Phi(), "sanity");
 341   int alias_idx = C->get_alias_index(adr_t);
 342   int offset = adr_t->offset();
 343   int instance_id = adr_t->instance_id();
 344 
 345   // Check if an appropriate value phi already exists.
 346   Node* region = mem->in(0);
 347   for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) {
 348     Node* phi = region->fast_out(k);
 349     if (phi->is_Phi() && phi != mem &&
 350         phi->as_Phi()->is_same_inst_field(phi_type, (int)mem->_idx, instance_id, alias_idx, offset)) {
 351       return phi;
 352     }
 353   }
 354   // Check if an appropriate new value phi already exists.
 355   Node* new_phi = value_phis->find(mem->_idx);
 356   if (new_phi != nullptr)
 357     return new_phi;
 358 
 359   if (level <= 0) {
 360     return nullptr; // Give up: phi tree too deep
 361   }
 362   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
 363   Node *alloc_mem = alloc->proj_out_or_null(TypeFunc::Memory, /*io_use:*/false);
 364   assert(alloc_mem != nullptr, "Allocation without a memory projection.");
 365 
 366   uint length = mem->req();
 367   GrowableArray <Node *> values(length, length, nullptr);
 368 
 369   // create a new Phi for the value
 370   PhiNode *phi = new PhiNode(mem->in(0), phi_type, nullptr, mem->_idx, instance_id, alias_idx, offset);
 371   transform_later(phi);
 372   value_phis->push(phi, mem->_idx);
 373 
 374   for (uint j = 1; j < length; j++) {
 375     Node *in = mem->in(j);
 376     if (in == nullptr || in->is_top()) {
 377       values.at_put(j, in);
 378     } else  {
 379       Node *val = scan_mem_chain(in, alias_idx, offset, start_mem, alloc, &_igvn);
 380       if (val == start_mem || val == alloc_mem) {
 381         // hit a sentinel, return appropriate 0 value
 382         values.at_put(j, _igvn.zerocon(ft));
 383         continue;
 384       }
 385       if (val->is_Initialize()) {
 386         val = val->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
 387       }
 388       if (val == nullptr) {
 389         return nullptr;  // can't find a value on this path
 390       }
 391       if (val == mem) {
 392         values.at_put(j, mem);
 393       } else if (val->is_Store()) {
 394         Node* n = val->in(MemNode::ValueIn);
 395         BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 396         n = bs->step_over_gc_barrier(n);
 397         if (is_subword_type(ft)) {
 398           n = Compile::narrow_value(ft, n, phi_type, &_igvn, true);
 399         }
 400         values.at_put(j, n);
 401       } else if(val->is_Proj() && val->in(0) == alloc) {
 402         values.at_put(j, _igvn.zerocon(ft));
 403       } else if (val->is_Phi()) {
 404         val = value_from_mem_phi(val, ft, phi_type, adr_t, alloc, value_phis, level-1);
 405         if (val == nullptr) {
 406           return nullptr;
 407         }
 408         values.at_put(j, val);
 409       } else if (val->Opcode() == Op_SCMemProj) {
 410         assert(val->in(0)->is_LoadStore() ||
 411                val->in(0)->Opcode() == Op_EncodeISOArray ||
 412                val->in(0)->Opcode() == Op_StrCompressedCopy, "sanity");
 413         assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
 414         return nullptr;
 415       } else if (val->is_ArrayCopy()) {
 416         Node* res = make_arraycopy_load(val->as_ArrayCopy(), offset, val->in(0), val->in(TypeFunc::Memory), ft, phi_type, alloc);
 417         if (res == nullptr) {
 418           return nullptr;
 419         }
 420         values.at_put(j, res);
 421       } else if (val->is_top()) {
 422         // This indicates that this path into the phi is dead. Top will eventually also propagate into the Region.
 423         // IGVN will clean this up later.
 424         values.at_put(j, val);
 425       } else {
 426         DEBUG_ONLY( val->dump(); )
 427         assert(false, "unknown node on this path");
 428         return nullptr;  // unknown node on this path
 429       }
 430     }
 431   }
 432   // Set Phi's inputs
 433   for (uint j = 1; j < length; j++) {
 434     if (values.at(j) == mem) {
 435       phi->init_req(j, phi);
 436     } else {
 437       phi->init_req(j, values.at(j));
 438     }
 439   }
 440   return phi;
 441 }
 442 
 443 // Search the last value stored into the object's field.
 444 Node *PhaseMacroExpand::value_from_mem(Node *sfpt_mem, Node *sfpt_ctl, BasicType ft, const Type *ftype, const TypeOopPtr *adr_t, AllocateNode *alloc) {
 445   assert(adr_t->is_known_instance_field(), "instance required");
 446   int instance_id = adr_t->instance_id();
 447   assert((uint)instance_id == alloc->_idx, "wrong allocation");
 448 
 449   int alias_idx = C->get_alias_index(adr_t);
 450   int offset = adr_t->offset();
 451   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
 452   Node *alloc_ctrl = alloc->in(TypeFunc::Control);
 453   Node *alloc_mem = alloc->proj_out_or_null(TypeFunc::Memory, /*io_use:*/false);
 454   assert(alloc_mem != nullptr, "Allocation without a memory projection.");
 455   VectorSet visited;
 456 
 457   bool done = sfpt_mem == alloc_mem;
 458   Node *mem = sfpt_mem;
 459   while (!done) {
 460     if (visited.test_set(mem->_idx)) {
 461       return nullptr;  // found a loop, give up
 462     }
 463     mem = scan_mem_chain(mem, alias_idx, offset, start_mem, alloc, &_igvn);
 464     if (mem == start_mem || mem == alloc_mem) {
 465       done = true;  // hit a sentinel, return appropriate 0 value
 466     } else if (mem->is_Initialize()) {
 467       mem = mem->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
 468       if (mem == nullptr) {
 469         done = true; // Something go wrong.
 470       } else if (mem->is_Store()) {
 471         const TypePtr* atype = mem->as_Store()->adr_type();
 472         assert(C->get_alias_index(atype) == Compile::AliasIdxRaw, "store is correct memory slice");
 473         done = true;
 474       }
 475     } else if (mem->is_Store()) {
 476       const TypeOopPtr* atype = mem->as_Store()->adr_type()->isa_oopptr();
 477       assert(atype != nullptr, "address type must be oopptr");
 478       assert(C->get_alias_index(atype) == alias_idx &&
 479              atype->is_known_instance_field() && atype->offset() == offset &&
 480              atype->instance_id() == instance_id, "store is correct memory slice");
 481       done = true;
 482     } else if (mem->is_Phi()) {
 483       // try to find a phi's unique input
 484       Node *unique_input = nullptr;
 485       Node *top = C->top();
 486       for (uint i = 1; i < mem->req(); i++) {
 487         Node *n = scan_mem_chain(mem->in(i), alias_idx, offset, start_mem, alloc, &_igvn);
 488         if (n == nullptr || n == top || n == mem) {
 489           continue;
 490         } else if (unique_input == nullptr) {
 491           unique_input = n;
 492         } else if (unique_input != n) {
 493           unique_input = top;
 494           break;
 495         }
 496       }
 497       if (unique_input != nullptr && unique_input != top) {
 498         mem = unique_input;
 499       } else {
 500         done = true;
 501       }
 502     } else if (mem->is_ArrayCopy()) {
 503       done = true;
 504     } else {
 505       DEBUG_ONLY( mem->dump(); )
 506       assert(false, "unexpected node");
 507     }
 508   }
 509   if (mem != nullptr) {
 510     if (mem == start_mem || mem == alloc_mem) {
 511       // hit a sentinel, return appropriate 0 value
 512       return _igvn.zerocon(ft);
 513     } else if (mem->is_Store()) {
 514       Node* n = mem->in(MemNode::ValueIn);
 515       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 516       n = bs->step_over_gc_barrier(n);
 517       return n;
 518     } else if (mem->is_Phi()) {
 519       // attempt to produce a Phi reflecting the values on the input paths of the Phi
 520       Node_Stack value_phis(8);
 521       Node* phi = value_from_mem_phi(mem, ft, ftype, adr_t, alloc, &value_phis, ValueSearchLimit);
 522       if (phi != nullptr) {
 523         return phi;
 524       } else {
 525         // Kill all new Phis
 526         while(value_phis.is_nonempty()) {
 527           Node* n = value_phis.node();
 528           _igvn.replace_node(n, C->top());
 529           value_phis.pop();
 530         }
 531       }
 532     } else if (mem->is_ArrayCopy()) {
 533       Node* ctl = mem->in(0);
 534       Node* m = mem->in(TypeFunc::Memory);
 535       if (sfpt_ctl->is_Proj() && sfpt_ctl->as_Proj()->is_uncommon_trap_proj()) {
 536         // pin the loads in the uncommon trap path
 537         ctl = sfpt_ctl;
 538         m = sfpt_mem;
 539       }
 540       return make_arraycopy_load(mem->as_ArrayCopy(), offset, ctl, m, ft, ftype, alloc);
 541     }
 542   }
 543   // Something go wrong.
 544   return nullptr;
 545 }
 546 
 547 // Check the possibility of scalar replacement.
 548 bool PhaseMacroExpand::can_eliminate_allocation(PhaseIterGVN* igvn, AllocateNode *alloc, GrowableArray <SafePointNode *>* safepoints) {
 549   //  Scan the uses of the allocation to check for anything that would
 550   //  prevent us from eliminating it.
 551   NOT_PRODUCT( const char* fail_eliminate = nullptr; )
 552   DEBUG_ONLY( Node* disq_node = nullptr; )
 553   bool can_eliminate = true;
 554   bool reduce_merge_precheck = (safepoints == nullptr);
 555 
 556   Node* res = alloc->result_cast();
 557   const TypeOopPtr* res_type = nullptr;
 558   if (res == nullptr) {
 559     // All users were eliminated.
 560   } else if (!res->is_CheckCastPP()) {
 561     NOT_PRODUCT(fail_eliminate = "Allocation does not have unique CheckCastPP";)
 562     can_eliminate = false;
 563   } else {
 564     res_type = igvn->type(res)->isa_oopptr();
 565     if (res_type == nullptr) {
 566       NOT_PRODUCT(fail_eliminate = "Neither instance or array allocation";)
 567       can_eliminate = false;
 568     } else if (!res_type->klass_is_exact()) {
 569       NOT_PRODUCT(fail_eliminate = "Not an exact type.";)
 570       can_eliminate = false;
 571     } else if (res_type->isa_aryptr()) {
 572       int length = alloc->in(AllocateNode::ALength)->find_int_con(-1);
 573       if (length < 0) {
 574         NOT_PRODUCT(fail_eliminate = "Array's size is not constant";)
 575         can_eliminate = false;
 576       }
 577     }
 578   }
 579 
 580   if (can_eliminate && res != nullptr) {
 581     BarrierSetC2 *bs = BarrierSet::barrier_set()->barrier_set_c2();
 582     for (DUIterator_Fast jmax, j = res->fast_outs(jmax);
 583                                j < jmax && can_eliminate; j++) {
 584       Node* use = res->fast_out(j);
 585 
 586       if (use->is_AddP()) {
 587         const TypePtr* addp_type = igvn->type(use)->is_ptr();
 588         int offset = addp_type->offset();
 589 
 590         if (offset == Type::OffsetTop || offset == Type::OffsetBot) {
 591           NOT_PRODUCT(fail_eliminate = "Undefined field reference";)
 592           can_eliminate = false;
 593           break;
 594         }
 595         for (DUIterator_Fast kmax, k = use->fast_outs(kmax);
 596                                    k < kmax && can_eliminate; k++) {
 597           Node* n = use->fast_out(k);
 598           if (!n->is_Store() && n->Opcode() != Op_CastP2X && !bs->is_gc_pre_barrier_node(n) && !reduce_merge_precheck) {
 599             DEBUG_ONLY(disq_node = n;)
 600             if (n->is_Load() || n->is_LoadStore()) {
 601               NOT_PRODUCT(fail_eliminate = "Field load";)
 602             } else {
 603               NOT_PRODUCT(fail_eliminate = "Not store field reference";)
 604             }
 605             can_eliminate = false;
 606           }
 607         }
 608       } else if (use->is_ArrayCopy() &&
 609                  (use->as_ArrayCopy()->is_clonebasic() ||
 610                   use->as_ArrayCopy()->is_arraycopy_validated() ||
 611                   use->as_ArrayCopy()->is_copyof_validated() ||
 612                   use->as_ArrayCopy()->is_copyofrange_validated()) &&
 613                  use->in(ArrayCopyNode::Dest) == res) {
 614         // ok to eliminate
 615       } else if (use->is_SafePoint()) {
 616         SafePointNode* sfpt = use->as_SafePoint();
 617         if (sfpt->is_Call() && sfpt->as_Call()->has_non_debug_use(res)) {
 618           // Object is passed as argument.
 619           DEBUG_ONLY(disq_node = use;)
 620           NOT_PRODUCT(fail_eliminate = "Object is passed as argument";)
 621           can_eliminate = false;
 622         }
 623         Node* sfptMem = sfpt->memory();
 624         if (sfptMem == nullptr || sfptMem->is_top()) {
 625           DEBUG_ONLY(disq_node = use;)
 626           NOT_PRODUCT(fail_eliminate = "null or TOP memory";)
 627           can_eliminate = false;
 628         } else if (!reduce_merge_precheck) {
 629           safepoints->append_if_missing(sfpt);
 630         }
 631       } else if (reduce_merge_precheck &&
 632                  (use->is_Phi() || use->is_EncodeP() ||
 633                   use->Opcode() == Op_MemBarRelease ||
 634                   (UseStoreStoreForCtor && use->Opcode() == Op_MemBarStoreStore))) {
 635         // Nothing to do
 636       } else if (use->Opcode() != Op_CastP2X) { // CastP2X is used by card mark
 637         if (use->is_Phi()) {
 638           if (use->outcnt() == 1 && use->unique_out()->Opcode() == Op_Return) {
 639             NOT_PRODUCT(fail_eliminate = "Object is return value";)
 640           } else {
 641             NOT_PRODUCT(fail_eliminate = "Object is referenced by Phi";)
 642           }
 643           DEBUG_ONLY(disq_node = use;)
 644         } else {
 645           if (use->Opcode() == Op_Return) {
 646             NOT_PRODUCT(fail_eliminate = "Object is return value";)
 647           } else {
 648             NOT_PRODUCT(fail_eliminate = "Object is referenced by node";)
 649           }
 650           DEBUG_ONLY(disq_node = use;)
 651         }
 652         can_eliminate = false;
 653       }
 654     }
 655   }
 656 
 657 #ifndef PRODUCT
 658   if (PrintEliminateAllocations && safepoints != nullptr) {
 659     if (can_eliminate) {
 660       tty->print("Scalar ");
 661       if (res == nullptr)
 662         alloc->dump();
 663       else
 664         res->dump();
 665     } else if (alloc->_is_scalar_replaceable) {
 666       tty->print("NotScalar (%s)", fail_eliminate);
 667       if (res == nullptr)
 668         alloc->dump();
 669       else
 670         res->dump();
 671 #ifdef ASSERT
 672       if (disq_node != nullptr) {
 673           tty->print("  >>>> ");
 674           disq_node->dump();
 675       }
 676 #endif /*ASSERT*/
 677     }
 678   }
 679 
 680   if (TraceReduceAllocationMerges && !can_eliminate && reduce_merge_precheck) {
 681     tty->print_cr("\tCan't eliminate allocation because '%s': ", fail_eliminate != nullptr ? fail_eliminate : "");
 682     DEBUG_ONLY(if (disq_node != nullptr) disq_node->dump();)
 683   }
 684 #endif
 685   return can_eliminate;
 686 }
 687 
 688 void PhaseMacroExpand::undo_previous_scalarizations(GrowableArray <SafePointNode *> safepoints_done, AllocateNode* alloc) {
 689   Node* res = alloc->result_cast();
 690   int nfields = 0;
 691   assert(res == nullptr || res->is_CheckCastPP(), "unexpected AllocateNode result");
 692 
 693   if (res != nullptr) {
 694     const TypeOopPtr* res_type = _igvn.type(res)->isa_oopptr();
 695 
 696     if (res_type->isa_instptr()) {
 697       // find the fields of the class which will be needed for safepoint debug information
 698       ciInstanceKlass* iklass = res_type->is_instptr()->instance_klass();
 699       nfields = iklass->nof_nonstatic_fields();
 700     } else {
 701       // find the array's elements which will be needed for safepoint debug information
 702       nfields = alloc->in(AllocateNode::ALength)->find_int_con(-1);
 703       assert(nfields >= 0, "must be an array klass.");
 704     }
 705   }
 706 
 707   // rollback processed safepoints
 708   while (safepoints_done.length() > 0) {
 709     SafePointNode* sfpt_done = safepoints_done.pop();
 710     // remove any extra entries we added to the safepoint
 711     uint last = sfpt_done->req() - 1;
 712     for (int k = 0;  k < nfields; k++) {
 713       sfpt_done->del_req(last--);
 714     }
 715     JVMState *jvms = sfpt_done->jvms();
 716     jvms->set_endoff(sfpt_done->req());
 717     // Now make a pass over the debug information replacing any references
 718     // to SafePointScalarObjectNode with the allocated object.
 719     int start = jvms->debug_start();
 720     int end   = jvms->debug_end();
 721     for (int i = start; i < end; i++) {
 722       if (sfpt_done->in(i)->is_SafePointScalarObject()) {
 723         SafePointScalarObjectNode* scobj = sfpt_done->in(i)->as_SafePointScalarObject();
 724         if (scobj->first_index(jvms) == sfpt_done->req() &&
 725             scobj->n_fields() == (uint)nfields) {
 726           assert(scobj->alloc() == alloc, "sanity");
 727           sfpt_done->set_req(i, res);
 728         }
 729       }
 730     }
 731     _igvn._worklist.push(sfpt_done);
 732   }
 733 }
 734 
 735 SafePointScalarObjectNode* PhaseMacroExpand::create_scalarized_object_description(AllocateNode *alloc, SafePointNode* sfpt) {
 736   // Fields of scalar objs are referenced only at the end
 737   // of regular debuginfo at the last (youngest) JVMS.
 738   // Record relative start index.
 739   ciInstanceKlass* iklass    = nullptr;
 740   BasicType basic_elem_type  = T_ILLEGAL;
 741   const Type* field_type     = nullptr;
 742   const TypeOopPtr* res_type = nullptr;
 743   int nfields                = 0;
 744   int array_base             = 0;
 745   int element_size           = 0;
 746   uint first_ind             = (sfpt->req() - sfpt->jvms()->scloff());
 747   Node* res                  = alloc->result_cast();
 748 
 749   assert(res == nullptr || res->is_CheckCastPP(), "unexpected AllocateNode result");
 750   assert(sfpt->jvms() != nullptr, "missed JVMS");
 751 
 752   if (res != nullptr) { // Could be null when there are no users
 753     res_type = _igvn.type(res)->isa_oopptr();
 754 
 755     if (res_type->isa_instptr()) {
 756       // find the fields of the class which will be needed for safepoint debug information
 757       iklass = res_type->is_instptr()->instance_klass();
 758       nfields = iklass->nof_nonstatic_fields();
 759     } else {
 760       // find the array's elements which will be needed for safepoint debug information
 761       nfields = alloc->in(AllocateNode::ALength)->find_int_con(-1);
 762       assert(nfields >= 0, "must be an array klass.");
 763       basic_elem_type = res_type->is_aryptr()->elem()->array_element_basic_type();
 764       array_base = arrayOopDesc::base_offset_in_bytes(basic_elem_type);
 765       element_size = type2aelembytes(basic_elem_type);
 766       field_type = res_type->is_aryptr()->elem();
 767     }
 768   }
 769 
 770   SafePointScalarObjectNode* sobj = new SafePointScalarObjectNode(res_type, alloc, first_ind, sfpt->jvms()->depth(), nfields);
 771   sobj->init_req(0, C->root());
 772   transform_later(sobj);
 773 
 774   // Scan object's fields adding an input to the safepoint for each field.
 775   for (int j = 0; j < nfields; j++) {
 776     intptr_t offset;
 777     ciField* field = nullptr;
 778     if (iklass != nullptr) {
 779       field = iklass->nonstatic_field_at(j);
 780       offset = field->offset_in_bytes();
 781       ciType* elem_type = field->type();
 782       basic_elem_type = field->layout_type();
 783 
 784       // The next code is taken from Parse::do_get_xxx().
 785       if (is_reference_type(basic_elem_type)) {
 786         if (!elem_type->is_loaded()) {
 787           field_type = TypeInstPtr::BOTTOM;
 788         } else if (field != nullptr && field->is_static_constant()) {
 789           ciObject* con = field->constant_value().as_object();
 790           // Do not "join" in the previous type; it doesn't add value,
 791           // and may yield a vacuous result if the field is of interface type.
 792           field_type = TypeOopPtr::make_from_constant(con)->isa_oopptr();
 793           assert(field_type != nullptr, "field singleton type must be consistent");
 794         } else {
 795           field_type = TypeOopPtr::make_from_klass(elem_type->as_klass());
 796         }
 797         if (UseCompressedOops) {
 798           field_type = field_type->make_narrowoop();
 799           basic_elem_type = T_NARROWOOP;
 800         }
 801       } else {
 802         field_type = Type::get_const_basic_type(basic_elem_type);
 803       }
 804     } else {
 805       offset = array_base + j * (intptr_t)element_size;
 806     }
 807 
 808     const TypeOopPtr *field_addr_type = res_type->add_offset(offset)->isa_oopptr();
 809 
 810     Node *field_val = value_from_mem(sfpt->memory(), sfpt->control(), basic_elem_type, field_type, field_addr_type, alloc);
 811 
 812     // We weren't able to find a value for this field,
 813     // give up on eliminating this allocation.
 814     if (field_val == nullptr) {
 815       uint last = sfpt->req() - 1;
 816       for (int k = 0;  k < j; k++) {
 817         sfpt->del_req(last--);
 818       }
 819       _igvn._worklist.push(sfpt);
 820 
 821 #ifndef PRODUCT
 822       if (PrintEliminateAllocations) {
 823         if (field != nullptr) {
 824           tty->print("=== At SafePoint node %d can't find value of field: ", sfpt->_idx);
 825           field->print();
 826           int field_idx = C->get_alias_index(field_addr_type);
 827           tty->print(" (alias_idx=%d)", field_idx);
 828         } else { // Array's element
 829           tty->print("=== At SafePoint node %d can't find value of array element [%d]", sfpt->_idx, j);
 830         }
 831         tty->print(", which prevents elimination of: ");
 832         if (res == nullptr)
 833           alloc->dump();
 834         else
 835           res->dump();
 836       }
 837 #endif
 838 
 839       return nullptr;
 840     }
 841 
 842     if (UseCompressedOops && field_type->isa_narrowoop()) {
 843       // Enable "DecodeN(EncodeP(Allocate)) --> Allocate" transformation
 844       // to be able scalar replace the allocation.
 845       if (field_val->is_EncodeP()) {
 846         field_val = field_val->in(1);
 847       } else {
 848         field_val = transform_later(new DecodeNNode(field_val, field_val->get_ptr_type()));
 849       }
 850     }
 851     sfpt->add_req(field_val);
 852   }
 853 
 854   sfpt->jvms()->set_endoff(sfpt->req());
 855 
 856   return sobj;
 857 }
 858 
 859 // Do scalar replacement.
 860 bool PhaseMacroExpand::scalar_replacement(AllocateNode *alloc, GrowableArray <SafePointNode *>& safepoints) {
 861   GrowableArray <SafePointNode *> safepoints_done;
 862   Node* res = alloc->result_cast();
 863   assert(res == nullptr || res->is_CheckCastPP(), "unexpected AllocateNode result");
 864 
 865   // Process the safepoint uses
 866   while (safepoints.length() > 0) {
 867     SafePointNode* sfpt = safepoints.pop();
 868     SafePointScalarObjectNode* sobj = create_scalarized_object_description(alloc, sfpt);
 869 
 870     if (sobj == nullptr) {
 871       undo_previous_scalarizations(safepoints_done, alloc);
 872       return false;
 873     }
 874 
 875     // Now make a pass over the debug information replacing any references
 876     // to the allocated object with "sobj"
 877     JVMState *jvms = sfpt->jvms();
 878     sfpt->replace_edges_in_range(res, sobj, jvms->debug_start(), jvms->debug_end(), &_igvn);
 879     _igvn._worklist.push(sfpt);
 880 
 881     // keep it for rollback
 882     safepoints_done.append_if_missing(sfpt);
 883   }
 884 
 885   return true;
 886 }
 887 
 888 static void disconnect_projections(MultiNode* n, PhaseIterGVN& igvn) {
 889   Node* ctl_proj = n->proj_out_or_null(TypeFunc::Control);
 890   Node* mem_proj = n->proj_out_or_null(TypeFunc::Memory);
 891   if (ctl_proj != nullptr) {
 892     igvn.replace_node(ctl_proj, n->in(0));
 893   }
 894   if (mem_proj != nullptr) {
 895     igvn.replace_node(mem_proj, n->in(TypeFunc::Memory));
 896   }
 897 }
 898 
 899 // Process users of eliminated allocation.
 900 void PhaseMacroExpand::process_users_of_allocation(CallNode *alloc) {
 901   Node* res = alloc->result_cast();
 902   if (res != nullptr) {
 903     for (DUIterator_Last jmin, j = res->last_outs(jmin); j >= jmin; ) {
 904       Node *use = res->last_out(j);
 905       uint oc1 = res->outcnt();
 906 
 907       if (use->is_AddP()) {
 908         for (DUIterator_Last kmin, k = use->last_outs(kmin); k >= kmin; ) {
 909           Node *n = use->last_out(k);
 910           uint oc2 = use->outcnt();
 911           if (n->is_Store()) {
 912 #ifdef ASSERT
 913             // Verify that there is no dependent MemBarVolatile nodes,
 914             // they should be removed during IGVN, see MemBarNode::Ideal().
 915             for (DUIterator_Fast pmax, p = n->fast_outs(pmax);
 916                                        p < pmax; p++) {
 917               Node* mb = n->fast_out(p);
 918               assert(mb->is_Initialize() || !mb->is_MemBar() ||
 919                      mb->req() <= MemBarNode::Precedent ||
 920                      mb->in(MemBarNode::Precedent) != n,
 921                      "MemBarVolatile should be eliminated for non-escaping object");
 922             }
 923 #endif
 924             _igvn.replace_node(n, n->in(MemNode::Memory));
 925           } else {
 926             eliminate_gc_barrier(n);
 927           }
 928           k -= (oc2 - use->outcnt());
 929         }
 930         _igvn.remove_dead_node(use);
 931       } else if (use->is_ArrayCopy()) {
 932         // Disconnect ArrayCopy node
 933         ArrayCopyNode* ac = use->as_ArrayCopy();
 934         if (ac->is_clonebasic()) {
 935           Node* membar_after = ac->proj_out(TypeFunc::Control)->unique_ctrl_out();
 936           disconnect_projections(ac, _igvn);
 937           assert(alloc->in(TypeFunc::Memory)->is_Proj() && alloc->in(TypeFunc::Memory)->in(0)->Opcode() == Op_MemBarCPUOrder, "mem barrier expected before allocation");
 938           Node* membar_before = alloc->in(TypeFunc::Memory)->in(0);
 939           disconnect_projections(membar_before->as_MemBar(), _igvn);
 940           if (membar_after->is_MemBar()) {
 941             disconnect_projections(membar_after->as_MemBar(), _igvn);
 942           }
 943         } else {
 944           assert(ac->is_arraycopy_validated() ||
 945                  ac->is_copyof_validated() ||
 946                  ac->is_copyofrange_validated(), "unsupported");
 947           CallProjections callprojs;
 948           ac->extract_projections(&callprojs, true);
 949 
 950           _igvn.replace_node(callprojs.fallthrough_ioproj, ac->in(TypeFunc::I_O));
 951           _igvn.replace_node(callprojs.fallthrough_memproj, ac->in(TypeFunc::Memory));
 952           _igvn.replace_node(callprojs.fallthrough_catchproj, ac->in(TypeFunc::Control));
 953 
 954           // Set control to top. IGVN will remove the remaining projections
 955           ac->set_req(0, top());
 956           ac->replace_edge(res, top(), &_igvn);
 957 
 958           // Disconnect src right away: it can help find new
 959           // opportunities for allocation elimination
 960           Node* src = ac->in(ArrayCopyNode::Src);
 961           ac->replace_edge(src, top(), &_igvn);
 962           // src can be top at this point if src and dest of the
 963           // arraycopy were the same
 964           if (src->outcnt() == 0 && !src->is_top()) {
 965             _igvn.remove_dead_node(src);
 966           }
 967         }
 968         _igvn._worklist.push(ac);
 969       } else {
 970         eliminate_gc_barrier(use);
 971       }
 972       j -= (oc1 - res->outcnt());
 973     }
 974     assert(res->outcnt() == 0, "all uses of allocated objects must be deleted");
 975     _igvn.remove_dead_node(res);
 976   }
 977 
 978   //
 979   // Process other users of allocation's projections
 980   //
 981   if (_callprojs.resproj != nullptr && _callprojs.resproj->outcnt() != 0) {
 982     // First disconnect stores captured by Initialize node.
 983     // If Initialize node is eliminated first in the following code,
 984     // it will kill such stores and DUIterator_Last will assert.
 985     for (DUIterator_Fast jmax, j = _callprojs.resproj->fast_outs(jmax);  j < jmax; j++) {
 986       Node* use = _callprojs.resproj->fast_out(j);
 987       if (use->is_AddP()) {
 988         // raw memory addresses used only by the initialization
 989         _igvn.replace_node(use, C->top());
 990         --j; --jmax;
 991       }
 992     }
 993     for (DUIterator_Last jmin, j = _callprojs.resproj->last_outs(jmin); j >= jmin; ) {
 994       Node* use = _callprojs.resproj->last_out(j);
 995       uint oc1 = _callprojs.resproj->outcnt();
 996       if (use->is_Initialize()) {
 997         // Eliminate Initialize node.
 998         InitializeNode *init = use->as_Initialize();
 999         assert(init->outcnt() <= 2, "only a control and memory projection expected");
1000         Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
1001         if (ctrl_proj != nullptr) {
1002           _igvn.replace_node(ctrl_proj, init->in(TypeFunc::Control));
1003 #ifdef ASSERT
1004           // If the InitializeNode has no memory out, it will die, and tmp will become null
1005           Node* tmp = init->in(TypeFunc::Control);
1006           assert(tmp == nullptr || tmp == _callprojs.fallthrough_catchproj, "allocation control projection");
1007 #endif
1008         }
1009         Node *mem_proj = init->proj_out_or_null(TypeFunc::Memory);
1010         if (mem_proj != nullptr) {
1011           Node *mem = init->in(TypeFunc::Memory);
1012 #ifdef ASSERT
1013           if (mem->is_MergeMem()) {
1014             assert(mem->in(TypeFunc::Memory) == _callprojs.fallthrough_memproj, "allocation memory projection");
1015           } else {
1016             assert(mem == _callprojs.fallthrough_memproj, "allocation memory projection");
1017           }
1018 #endif
1019           _igvn.replace_node(mem_proj, mem);
1020         }
1021       } else  {
1022         assert(false, "only Initialize or AddP expected");
1023       }
1024       j -= (oc1 - _callprojs.resproj->outcnt());
1025     }
1026   }
1027   if (_callprojs.fallthrough_catchproj != nullptr) {
1028     _igvn.replace_node(_callprojs.fallthrough_catchproj, alloc->in(TypeFunc::Control));
1029   }
1030   if (_callprojs.fallthrough_memproj != nullptr) {
1031     _igvn.replace_node(_callprojs.fallthrough_memproj, alloc->in(TypeFunc::Memory));
1032   }
1033   if (_callprojs.catchall_memproj != nullptr) {
1034     _igvn.replace_node(_callprojs.catchall_memproj, C->top());
1035   }
1036   if (_callprojs.fallthrough_ioproj != nullptr) {
1037     _igvn.replace_node(_callprojs.fallthrough_ioproj, alloc->in(TypeFunc::I_O));
1038   }
1039   if (_callprojs.catchall_ioproj != nullptr) {
1040     _igvn.replace_node(_callprojs.catchall_ioproj, C->top());
1041   }
1042   if (_callprojs.catchall_catchproj != nullptr) {
1043     _igvn.replace_node(_callprojs.catchall_catchproj, C->top());
1044   }
1045 }
1046 
1047 bool PhaseMacroExpand::eliminate_allocate_node(AllocateNode *alloc) {
1048   // If reallocation fails during deoptimization we'll pop all
1049   // interpreter frames for this compiled frame and that won't play
1050   // nice with JVMTI popframe.
1051   // We avoid this issue by eager reallocation when the popframe request
1052   // is received.
1053   if (!EliminateAllocations || !alloc->_is_non_escaping) {
1054     return false;
1055   }
1056   Node* klass = alloc->in(AllocateNode::KlassNode);
1057   const TypeKlassPtr* tklass = _igvn.type(klass)->is_klassptr();
1058   Node* res = alloc->result_cast();
1059   // Eliminate boxing allocations which are not used
1060   // regardless scalar replaceable status.
1061   bool boxing_alloc = C->eliminate_boxing() &&
1062                       tklass->isa_instklassptr() &&
1063                       tklass->is_instklassptr()->instance_klass()->is_box_klass();
1064   if (!alloc->_is_scalar_replaceable && (!boxing_alloc || (res != nullptr))) {
1065     return false;
1066   }
1067 
1068   alloc->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1069 
1070   GrowableArray <SafePointNode *> safepoints;
1071   if (!can_eliminate_allocation(&_igvn, alloc, &safepoints)) {
1072     return false;
1073   }
1074 
1075   if (!alloc->_is_scalar_replaceable) {
1076     assert(res == nullptr, "sanity");
1077     // We can only eliminate allocation if all debug info references
1078     // are already replaced with SafePointScalarObject because
1079     // we can't search for a fields value without instance_id.
1080     if (safepoints.length() > 0) {
1081       return false;
1082     }
1083   }
1084 
1085   if (!scalar_replacement(alloc, safepoints)) {
1086     return false;
1087   }
1088 
1089   CompileLog* log = C->log();
1090   if (log != nullptr) {
1091     log->head("eliminate_allocation type='%d'",
1092               log->identify(tklass->exact_klass()));
1093     JVMState* p = alloc->jvms();
1094     while (p != nullptr) {
1095       log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
1096       p = p->caller();
1097     }
1098     log->tail("eliminate_allocation");
1099   }
1100 
1101   process_users_of_allocation(alloc);
1102 
1103 #ifndef PRODUCT
1104   if (PrintEliminateAllocations) {
1105     if (alloc->is_AllocateArray())
1106       tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
1107     else
1108       tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
1109   }
1110 #endif
1111 
1112   return true;
1113 }
1114 
1115 bool PhaseMacroExpand::eliminate_boxing_node(CallStaticJavaNode *boxing) {
1116   // EA should remove all uses of non-escaping boxing node.
1117   if (!C->eliminate_boxing() || boxing->proj_out_or_null(TypeFunc::Parms) != nullptr) {
1118     return false;
1119   }
1120 
1121   assert(boxing->result_cast() == nullptr, "unexpected boxing node result");
1122 
1123   boxing->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1124 
1125   const TypeTuple* r = boxing->tf()->range();
1126   assert(r->cnt() > TypeFunc::Parms, "sanity");
1127   const TypeInstPtr* t = r->field_at(TypeFunc::Parms)->isa_instptr();
1128   assert(t != nullptr, "sanity");
1129 
1130   CompileLog* log = C->log();
1131   if (log != nullptr) {
1132     log->head("eliminate_boxing type='%d'",
1133               log->identify(t->instance_klass()));
1134     JVMState* p = boxing->jvms();
1135     while (p != nullptr) {
1136       log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
1137       p = p->caller();
1138     }
1139     log->tail("eliminate_boxing");
1140   }
1141 
1142   process_users_of_allocation(boxing);
1143 
1144 #ifndef PRODUCT
1145   if (PrintEliminateAllocations) {
1146     tty->print("++++ Eliminated: %d ", boxing->_idx);
1147     boxing->method()->print_short_name(tty);
1148     tty->cr();
1149   }
1150 #endif
1151 
1152   return true;
1153 }
1154 
1155 
1156 Node* PhaseMacroExpand::make_load(Node* ctl, Node* mem, Node* base, int offset, const Type* value_type, BasicType bt) {
1157   Node* adr = basic_plus_adr(base, offset);
1158   const TypePtr* adr_type = adr->bottom_type()->is_ptr();
1159   Node* value = LoadNode::make(_igvn, ctl, mem, adr, adr_type, value_type, bt, MemNode::unordered);
1160   transform_later(value);
1161   return value;
1162 }
1163 
1164 
1165 Node* PhaseMacroExpand::make_store(Node* ctl, Node* mem, Node* base, int offset, Node* value, BasicType bt) {
1166   Node* adr = basic_plus_adr(base, offset);
1167   mem = StoreNode::make(_igvn, ctl, mem, adr, nullptr, value, bt, MemNode::unordered);
1168   transform_later(mem);
1169   return mem;
1170 }
1171 
1172 //=============================================================================
1173 //
1174 //                              A L L O C A T I O N
1175 //
1176 // Allocation attempts to be fast in the case of frequent small objects.
1177 // It breaks down like this:
1178 //
1179 // 1) Size in doublewords is computed.  This is a constant for objects and
1180 // variable for most arrays.  Doubleword units are used to avoid size
1181 // overflow of huge doubleword arrays.  We need doublewords in the end for
1182 // rounding.
1183 //
1184 // 2) Size is checked for being 'too large'.  Too-large allocations will go
1185 // the slow path into the VM.  The slow path can throw any required
1186 // exceptions, and does all the special checks for very large arrays.  The
1187 // size test can constant-fold away for objects.  For objects with
1188 // finalizers it constant-folds the otherway: you always go slow with
1189 // finalizers.
1190 //
1191 // 3) If NOT using TLABs, this is the contended loop-back point.
1192 // Load-Locked the heap top.  If using TLABs normal-load the heap top.
1193 //
1194 // 4) Check that heap top + size*8 < max.  If we fail go the slow ` route.
1195 // NOTE: "top+size*8" cannot wrap the 4Gig line!  Here's why: for largish
1196 // "size*8" we always enter the VM, where "largish" is a constant picked small
1197 // enough that there's always space between the eden max and 4Gig (old space is
1198 // there so it's quite large) and large enough that the cost of entering the VM
1199 // is dwarfed by the cost to initialize the space.
1200 //
1201 // 5) If NOT using TLABs, Store-Conditional the adjusted heap top back
1202 // down.  If contended, repeat at step 3.  If using TLABs normal-store
1203 // adjusted heap top back down; there is no contention.
1204 //
1205 // 6) If !ZeroTLAB then Bulk-clear the object/array.  Fill in klass & mark
1206 // fields.
1207 //
1208 // 7) Merge with the slow-path; cast the raw memory pointer to the correct
1209 // oop flavor.
1210 //
1211 //=============================================================================
1212 // FastAllocateSizeLimit value is in DOUBLEWORDS.
1213 // Allocations bigger than this always go the slow route.
1214 // This value must be small enough that allocation attempts that need to
1215 // trigger exceptions go the slow route.  Also, it must be small enough so
1216 // that heap_top + size_in_bytes does not wrap around the 4Gig limit.
1217 //=============================================================================j//
1218 // %%% Here is an old comment from parseHelper.cpp; is it outdated?
1219 // The allocator will coalesce int->oop copies away.  See comment in
1220 // coalesce.cpp about how this works.  It depends critically on the exact
1221 // code shape produced here, so if you are changing this code shape
1222 // make sure the GC info for the heap-top is correct in and around the
1223 // slow-path call.
1224 //
1225 
1226 void PhaseMacroExpand::expand_allocate_common(
1227             AllocateNode* alloc, // allocation node to be expanded
1228             Node* length,  // array length for an array allocation
1229             const TypeFunc* slow_call_type, // Type of slow call
1230             address slow_call_address,  // Address of slow call
1231             Node* valid_length_test // whether length is valid or not
1232     )
1233 {
1234   Node* ctrl = alloc->in(TypeFunc::Control);
1235   Node* mem  = alloc->in(TypeFunc::Memory);
1236   Node* i_o  = alloc->in(TypeFunc::I_O);
1237   Node* size_in_bytes     = alloc->in(AllocateNode::AllocSize);
1238   Node* klass_node        = alloc->in(AllocateNode::KlassNode);
1239   Node* initial_slow_test = alloc->in(AllocateNode::InitialTest);
1240   assert(ctrl != nullptr, "must have control");
1241 
1242   // We need a Region and corresponding Phi's to merge the slow-path and fast-path results.
1243   // they will not be used if "always_slow" is set
1244   enum { slow_result_path = 1, fast_result_path = 2 };
1245   Node *result_region = nullptr;
1246   Node *result_phi_rawmem = nullptr;
1247   Node *result_phi_rawoop = nullptr;
1248   Node *result_phi_i_o = nullptr;
1249 
1250   // The initial slow comparison is a size check, the comparison
1251   // we want to do is a BoolTest::gt
1252   bool expand_fast_path = true;
1253   int tv = _igvn.find_int_con(initial_slow_test, -1);
1254   if (tv >= 0) {
1255     // InitialTest has constant result
1256     //   0 - can fit in TLAB
1257     //   1 - always too big or negative
1258     assert(tv <= 1, "0 or 1 if a constant");
1259     expand_fast_path = (tv == 0);
1260     initial_slow_test = nullptr;
1261   } else {
1262     initial_slow_test = BoolNode::make_predicate(initial_slow_test, &_igvn);
1263   }
1264 
1265   if (!UseTLAB) {
1266     // Force slow-path allocation
1267     expand_fast_path = false;
1268     initial_slow_test = nullptr;
1269   }
1270 
1271   bool allocation_has_use = (alloc->result_cast() != nullptr);
1272   if (!allocation_has_use) {
1273     InitializeNode* init = alloc->initialization();
1274     if (init != nullptr) {
1275       init->remove(&_igvn);
1276     }
1277     if (expand_fast_path && (initial_slow_test == nullptr)) {
1278       // Remove allocation node and return.
1279       // Size is a non-negative constant -> no initial check needed -> directly to fast path.
1280       // Also, no usages -> empty fast path -> no fall out to slow path -> nothing left.
1281 #ifndef PRODUCT
1282       if (PrintEliminateAllocations) {
1283         tty->print("NotUsed ");
1284         Node* res = alloc->proj_out_or_null(TypeFunc::Parms);
1285         if (res != nullptr) {
1286           res->dump();
1287         } else {
1288           alloc->dump();
1289         }
1290       }
1291 #endif
1292       yank_alloc_node(alloc);
1293       return;
1294     }
1295   }
1296 
1297   enum { too_big_or_final_path = 1, need_gc_path = 2 };
1298   Node *slow_region = nullptr;
1299   Node *toobig_false = ctrl;
1300 
1301   // generate the initial test if necessary
1302   if (initial_slow_test != nullptr ) {
1303     assert (expand_fast_path, "Only need test if there is a fast path");
1304     slow_region = new RegionNode(3);
1305 
1306     // Now make the initial failure test.  Usually a too-big test but
1307     // might be a TRUE for finalizers.
1308     IfNode *toobig_iff = new IfNode(ctrl, initial_slow_test, PROB_MIN, COUNT_UNKNOWN);
1309     transform_later(toobig_iff);
1310     // Plug the failing-too-big test into the slow-path region
1311     Node *toobig_true = new IfTrueNode( toobig_iff );
1312     transform_later(toobig_true);
1313     slow_region    ->init_req( too_big_or_final_path, toobig_true );
1314     toobig_false = new IfFalseNode( toobig_iff );
1315     transform_later(toobig_false);
1316   } else {
1317     // No initial test, just fall into next case
1318     assert(allocation_has_use || !expand_fast_path, "Should already have been handled");
1319     toobig_false = ctrl;
1320     DEBUG_ONLY(slow_region = NodeSentinel);
1321   }
1322 
1323   // If we are here there are several possibilities
1324   // - expand_fast_path is false - then only a slow path is expanded. That's it.
1325   // no_initial_check means a constant allocation.
1326   // - If check always evaluates to false -> expand_fast_path is false (see above)
1327   // - If check always evaluates to true -> directly into fast path (but may bailout to slowpath)
1328   // if !allocation_has_use the fast path is empty
1329   // if !allocation_has_use && no_initial_check
1330   // - Then there are no fastpath that can fall out to slowpath -> no allocation code at all.
1331   //   removed by yank_alloc_node above.
1332 
1333   Node *slow_mem = mem;  // save the current memory state for slow path
1334   // generate the fast allocation code unless we know that the initial test will always go slow
1335   if (expand_fast_path) {
1336     // Fast path modifies only raw memory.
1337     if (mem->is_MergeMem()) {
1338       mem = mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
1339     }
1340 
1341     // allocate the Region and Phi nodes for the result
1342     result_region = new RegionNode(3);
1343     result_phi_rawmem = new PhiNode(result_region, Type::MEMORY, TypeRawPtr::BOTTOM);
1344     result_phi_i_o    = new PhiNode(result_region, Type::ABIO); // I/O is used for Prefetch
1345 
1346     // Grab regular I/O before optional prefetch may change it.
1347     // Slow-path does no I/O so just set it to the original I/O.
1348     result_phi_i_o->init_req(slow_result_path, i_o);
1349 
1350     // Name successful fast-path variables
1351     Node* fast_oop_ctrl;
1352     Node* fast_oop_rawmem;
1353     if (allocation_has_use) {
1354       Node* needgc_ctrl = nullptr;
1355       result_phi_rawoop = new PhiNode(result_region, TypeRawPtr::BOTTOM);
1356 
1357       intx prefetch_lines = length != nullptr ? AllocatePrefetchLines : AllocateInstancePrefetchLines;
1358       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1359       Node* fast_oop = bs->obj_allocate(this, mem, toobig_false, size_in_bytes, i_o, needgc_ctrl,
1360                                         fast_oop_ctrl, fast_oop_rawmem,
1361                                         prefetch_lines);
1362 
1363       if (initial_slow_test != nullptr) {
1364         // This completes all paths into the slow merge point
1365         slow_region->init_req(need_gc_path, needgc_ctrl);
1366         transform_later(slow_region);
1367       } else {
1368         // No initial slow path needed!
1369         // Just fall from the need-GC path straight into the VM call.
1370         slow_region = needgc_ctrl;
1371       }
1372 
1373       InitializeNode* init = alloc->initialization();
1374       fast_oop_rawmem = initialize_object(alloc,
1375                                           fast_oop_ctrl, fast_oop_rawmem, fast_oop,
1376                                           klass_node, length, size_in_bytes);
1377       expand_initialize_membar(alloc, init, fast_oop_ctrl, fast_oop_rawmem);
1378       expand_dtrace_alloc_probe(alloc, fast_oop, fast_oop_ctrl, fast_oop_rawmem);
1379 
1380       result_phi_rawoop->init_req(fast_result_path, fast_oop);
1381     } else {
1382       assert (initial_slow_test != nullptr, "sanity");
1383       fast_oop_ctrl   = toobig_false;
1384       fast_oop_rawmem = mem;
1385       transform_later(slow_region);
1386     }
1387 
1388     // Plug in the successful fast-path into the result merge point
1389     result_region    ->init_req(fast_result_path, fast_oop_ctrl);
1390     result_phi_i_o   ->init_req(fast_result_path, i_o);
1391     result_phi_rawmem->init_req(fast_result_path, fast_oop_rawmem);
1392   } else {
1393     slow_region = ctrl;
1394     result_phi_i_o = i_o; // Rename it to use in the following code.
1395   }
1396 
1397   // Generate slow-path call
1398   CallNode *call = new CallStaticJavaNode(slow_call_type, slow_call_address,
1399                                OptoRuntime::stub_name(slow_call_address),
1400                                TypePtr::BOTTOM);
1401   call->init_req(TypeFunc::Control,   slow_region);
1402   call->init_req(TypeFunc::I_O,       top());    // does no i/o
1403   call->init_req(TypeFunc::Memory,    slow_mem); // may gc ptrs
1404   call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
1405   call->init_req(TypeFunc::FramePtr,  alloc->in(TypeFunc::FramePtr));
1406 
1407   call->init_req(TypeFunc::Parms+0, klass_node);
1408   if (length != nullptr) {
1409     call->init_req(TypeFunc::Parms+1, length);
1410   }
1411 
1412   // Copy debug information and adjust JVMState information, then replace
1413   // allocate node with the call
1414   call->copy_call_debug_info(&_igvn, alloc);
1415   // For array allocations, copy the valid length check to the call node so Compile::final_graph_reshaping() can verify
1416   // that the call has the expected number of CatchProj nodes (in case the allocation always fails and the fallthrough
1417   // path dies).
1418   if (valid_length_test != nullptr) {
1419     call->add_req(valid_length_test);
1420   }
1421   if (expand_fast_path) {
1422     call->set_cnt(PROB_UNLIKELY_MAG(4));  // Same effect as RC_UNCOMMON.
1423   } else {
1424     // Hook i_o projection to avoid its elimination during allocation
1425     // replacement (when only a slow call is generated).
1426     call->set_req(TypeFunc::I_O, result_phi_i_o);
1427   }
1428   _igvn.replace_node(alloc, call);
1429   transform_later(call);
1430 
1431   // Identify the output projections from the allocate node and
1432   // adjust any references to them.
1433   // The control and io projections look like:
1434   //
1435   //        v---Proj(ctrl) <-----+   v---CatchProj(ctrl)
1436   //  Allocate                   Catch
1437   //        ^---Proj(io) <-------+   ^---CatchProj(io)
1438   //
1439   //  We are interested in the CatchProj nodes.
1440   //
1441   call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1442 
1443   // An allocate node has separate memory projections for the uses on
1444   // the control and i_o paths. Replace the control memory projection with
1445   // result_phi_rawmem (unless we are only generating a slow call when
1446   // both memory projections are combined)
1447   if (expand_fast_path && _callprojs.fallthrough_memproj != nullptr) {
1448     migrate_outs(_callprojs.fallthrough_memproj, result_phi_rawmem);
1449   }
1450   // Now change uses of catchall_memproj to use fallthrough_memproj and delete
1451   // catchall_memproj so we end up with a call that has only 1 memory projection.
1452   if (_callprojs.catchall_memproj != nullptr ) {
1453     if (_callprojs.fallthrough_memproj == nullptr) {
1454       _callprojs.fallthrough_memproj = new ProjNode(call, TypeFunc::Memory);
1455       transform_later(_callprojs.fallthrough_memproj);
1456     }
1457     migrate_outs(_callprojs.catchall_memproj, _callprojs.fallthrough_memproj);
1458     _igvn.remove_dead_node(_callprojs.catchall_memproj);
1459   }
1460 
1461   // An allocate node has separate i_o projections for the uses on the control
1462   // and i_o paths. Always replace the control i_o projection with result i_o
1463   // otherwise incoming i_o become dead when only a slow call is generated
1464   // (it is different from memory projections where both projections are
1465   // combined in such case).
1466   if (_callprojs.fallthrough_ioproj != nullptr) {
1467     migrate_outs(_callprojs.fallthrough_ioproj, result_phi_i_o);
1468   }
1469   // Now change uses of catchall_ioproj to use fallthrough_ioproj and delete
1470   // catchall_ioproj so we end up with a call that has only 1 i_o projection.
1471   if (_callprojs.catchall_ioproj != nullptr ) {
1472     if (_callprojs.fallthrough_ioproj == nullptr) {
1473       _callprojs.fallthrough_ioproj = new ProjNode(call, TypeFunc::I_O);
1474       transform_later(_callprojs.fallthrough_ioproj);
1475     }
1476     migrate_outs(_callprojs.catchall_ioproj, _callprojs.fallthrough_ioproj);
1477     _igvn.remove_dead_node(_callprojs.catchall_ioproj);
1478   }
1479 
1480   // if we generated only a slow call, we are done
1481   if (!expand_fast_path) {
1482     // Now we can unhook i_o.
1483     if (result_phi_i_o->outcnt() > 1) {
1484       call->set_req(TypeFunc::I_O, top());
1485     } else {
1486       assert(result_phi_i_o->unique_ctrl_out() == call, "sanity");
1487       // Case of new array with negative size known during compilation.
1488       // AllocateArrayNode::Ideal() optimization disconnect unreachable
1489       // following code since call to runtime will throw exception.
1490       // As result there will be no users of i_o after the call.
1491       // Leave i_o attached to this call to avoid problems in preceding graph.
1492     }
1493     return;
1494   }
1495 
1496   if (_callprojs.fallthrough_catchproj != nullptr) {
1497     ctrl = _callprojs.fallthrough_catchproj->clone();
1498     transform_later(ctrl);
1499     _igvn.replace_node(_callprojs.fallthrough_catchproj, result_region);
1500   } else {
1501     ctrl = top();
1502   }
1503   Node *slow_result;
1504   if (_callprojs.resproj == nullptr) {
1505     // no uses of the allocation result
1506     slow_result = top();
1507   } else {
1508     slow_result = _callprojs.resproj->clone();
1509     transform_later(slow_result);
1510     _igvn.replace_node(_callprojs.resproj, result_phi_rawoop);
1511   }
1512 
1513   // Plug slow-path into result merge point
1514   result_region->init_req( slow_result_path, ctrl);
1515   transform_later(result_region);
1516   if (allocation_has_use) {
1517     result_phi_rawoop->init_req(slow_result_path, slow_result);
1518     transform_later(result_phi_rawoop);
1519   }
1520   result_phi_rawmem->init_req(slow_result_path, _callprojs.fallthrough_memproj);
1521   transform_later(result_phi_rawmem);
1522   transform_later(result_phi_i_o);
1523   // This completes all paths into the result merge point
1524 }
1525 
1526 // Remove alloc node that has no uses.
1527 void PhaseMacroExpand::yank_alloc_node(AllocateNode* alloc) {
1528   Node* ctrl = alloc->in(TypeFunc::Control);
1529   Node* mem  = alloc->in(TypeFunc::Memory);
1530   Node* i_o  = alloc->in(TypeFunc::I_O);
1531 
1532   alloc->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1533   if (_callprojs.resproj != nullptr) {
1534     for (DUIterator_Fast imax, i = _callprojs.resproj->fast_outs(imax); i < imax; i++) {
1535       Node* use = _callprojs.resproj->fast_out(i);
1536       use->isa_MemBar()->remove(&_igvn);
1537       --imax;
1538       --i; // back up iterator
1539     }
1540     assert(_callprojs.resproj->outcnt() == 0, "all uses must be deleted");
1541     _igvn.remove_dead_node(_callprojs.resproj);
1542   }
1543   if (_callprojs.fallthrough_catchproj != nullptr) {
1544     migrate_outs(_callprojs.fallthrough_catchproj, ctrl);
1545     _igvn.remove_dead_node(_callprojs.fallthrough_catchproj);
1546   }
1547   if (_callprojs.catchall_catchproj != nullptr) {
1548     _igvn.rehash_node_delayed(_callprojs.catchall_catchproj);
1549     _callprojs.catchall_catchproj->set_req(0, top());
1550   }
1551   if (_callprojs.fallthrough_proj != nullptr) {
1552     Node* catchnode = _callprojs.fallthrough_proj->unique_ctrl_out();
1553     _igvn.remove_dead_node(catchnode);
1554     _igvn.remove_dead_node(_callprojs.fallthrough_proj);
1555   }
1556   if (_callprojs.fallthrough_memproj != nullptr) {
1557     migrate_outs(_callprojs.fallthrough_memproj, mem);
1558     _igvn.remove_dead_node(_callprojs.fallthrough_memproj);
1559   }
1560   if (_callprojs.fallthrough_ioproj != nullptr) {
1561     migrate_outs(_callprojs.fallthrough_ioproj, i_o);
1562     _igvn.remove_dead_node(_callprojs.fallthrough_ioproj);
1563   }
1564   if (_callprojs.catchall_memproj != nullptr) {
1565     _igvn.rehash_node_delayed(_callprojs.catchall_memproj);
1566     _callprojs.catchall_memproj->set_req(0, top());
1567   }
1568   if (_callprojs.catchall_ioproj != nullptr) {
1569     _igvn.rehash_node_delayed(_callprojs.catchall_ioproj);
1570     _callprojs.catchall_ioproj->set_req(0, top());
1571   }
1572 #ifndef PRODUCT
1573   if (PrintEliminateAllocations) {
1574     if (alloc->is_AllocateArray()) {
1575       tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
1576     } else {
1577       tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
1578     }
1579   }
1580 #endif
1581   _igvn.remove_dead_node(alloc);
1582 }
1583 
1584 void PhaseMacroExpand::expand_initialize_membar(AllocateNode* alloc, InitializeNode* init,
1585                                                 Node*& fast_oop_ctrl, Node*& fast_oop_rawmem) {
1586   // If initialization is performed by an array copy, any required
1587   // MemBarStoreStore was already added. If the object does not
1588   // escape no need for a MemBarStoreStore. If the object does not
1589   // escape in its initializer and memory barrier (MemBarStoreStore or
1590   // stronger) is already added at exit of initializer, also no need
1591   // for a MemBarStoreStore. Otherwise we need a MemBarStoreStore
1592   // so that stores that initialize this object can't be reordered
1593   // with a subsequent store that makes this object accessible by
1594   // other threads.
1595   // Other threads include java threads and JVM internal threads
1596   // (for example concurrent GC threads). Current concurrent GC
1597   // implementation: G1 will not scan newly created object,
1598   // so it's safe to skip storestore barrier when allocation does
1599   // not escape.
1600   if (!alloc->does_not_escape_thread() &&
1601     !alloc->is_allocation_MemBar_redundant() &&
1602     (init == nullptr || !init->is_complete_with_arraycopy())) {
1603     if (init == nullptr || init->req() < InitializeNode::RawStores) {
1604       // No InitializeNode or no stores captured by zeroing
1605       // elimination. Simply add the MemBarStoreStore after object
1606       // initialization.
1607       MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot);
1608       transform_later(mb);
1609 
1610       mb->init_req(TypeFunc::Memory, fast_oop_rawmem);
1611       mb->init_req(TypeFunc::Control, fast_oop_ctrl);
1612       fast_oop_ctrl = new ProjNode(mb, TypeFunc::Control);
1613       transform_later(fast_oop_ctrl);
1614       fast_oop_rawmem = new ProjNode(mb, TypeFunc::Memory);
1615       transform_later(fast_oop_rawmem);
1616     } else {
1617       // Add the MemBarStoreStore after the InitializeNode so that
1618       // all stores performing the initialization that were moved
1619       // before the InitializeNode happen before the storestore
1620       // barrier.
1621 
1622       Node* init_ctrl = init->proj_out_or_null(TypeFunc::Control);
1623       Node* init_mem = init->proj_out_or_null(TypeFunc::Memory);
1624 
1625       MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot);
1626       transform_later(mb);
1627 
1628       Node* ctrl = new ProjNode(init, TypeFunc::Control);
1629       transform_later(ctrl);
1630       Node* mem = new ProjNode(init, TypeFunc::Memory);
1631       transform_later(mem);
1632 
1633       // The MemBarStoreStore depends on control and memory coming
1634       // from the InitializeNode
1635       mb->init_req(TypeFunc::Memory, mem);
1636       mb->init_req(TypeFunc::Control, ctrl);
1637 
1638       ctrl = new ProjNode(mb, TypeFunc::Control);
1639       transform_later(ctrl);
1640       mem = new ProjNode(mb, TypeFunc::Memory);
1641       transform_later(mem);
1642 
1643       // All nodes that depended on the InitializeNode for control
1644       // and memory must now depend on the MemBarNode that itself
1645       // depends on the InitializeNode
1646       if (init_ctrl != nullptr) {
1647         _igvn.replace_node(init_ctrl, ctrl);
1648       }
1649       if (init_mem != nullptr) {
1650         _igvn.replace_node(init_mem, mem);
1651       }
1652     }
1653   }
1654 }
1655 
1656 void PhaseMacroExpand::expand_dtrace_alloc_probe(AllocateNode* alloc, Node* oop,
1657                                                 Node*& ctrl, Node*& rawmem) {
1658   if (C->env()->dtrace_alloc_probes()) {
1659     // Slow-path call
1660     int size = TypeFunc::Parms + 2;
1661     CallLeafNode *call = new CallLeafNode(OptoRuntime::dtrace_object_alloc_Type(),
1662                                           CAST_FROM_FN_PTR(address,
1663                                           static_cast<int (*)(JavaThread*, oopDesc*)>(SharedRuntime::dtrace_object_alloc)),
1664                                           "dtrace_object_alloc",
1665                                           TypeRawPtr::BOTTOM);
1666 
1667     // Get base of thread-local storage area
1668     Node* thread = new ThreadLocalNode();
1669     transform_later(thread);
1670 
1671     call->init_req(TypeFunc::Parms + 0, thread);
1672     call->init_req(TypeFunc::Parms + 1, oop);
1673     call->init_req(TypeFunc::Control, ctrl);
1674     call->init_req(TypeFunc::I_O    , top()); // does no i/o
1675     call->init_req(TypeFunc::Memory , rawmem);
1676     call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
1677     call->init_req(TypeFunc::FramePtr, alloc->in(TypeFunc::FramePtr));
1678     transform_later(call);
1679     ctrl = new ProjNode(call, TypeFunc::Control);
1680     transform_later(ctrl);
1681     rawmem = new ProjNode(call, TypeFunc::Memory);
1682     transform_later(rawmem);
1683   }
1684 }
1685 
1686 // Helper for PhaseMacroExpand::expand_allocate_common.
1687 // Initializes the newly-allocated storage.
1688 Node*
1689 PhaseMacroExpand::initialize_object(AllocateNode* alloc,
1690                                     Node* control, Node* rawmem, Node* object,
1691                                     Node* klass_node, Node* length,
1692                                     Node* size_in_bytes) {
1693   InitializeNode* init = alloc->initialization();
1694   // Store the klass & mark bits
1695   Node* mark_node = alloc->make_ideal_mark(&_igvn, object, control, rawmem);
1696   if (!mark_node->is_Con()) {
1697     transform_later(mark_node);
1698   }
1699   rawmem = make_store(control, rawmem, object, oopDesc::mark_offset_in_bytes(), mark_node, TypeX_X->basic_type());
1700 
1701   if (!UseCompactObjectHeaders) {
1702     rawmem = make_store(control, rawmem, object, Type::klass_offset(), klass_node, T_METADATA);
1703   }
1704   int header_size = alloc->minimum_header_size();  // conservatively small
1705 
1706   // Array length
1707   if (length != nullptr) {         // Arrays need length field
1708     rawmem = make_store(control, rawmem, object, arrayOopDesc::length_offset_in_bytes(), length, T_INT);
1709     // conservatively small header size:
1710     header_size = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1711     if (_igvn.type(klass_node)->isa_aryklassptr()) {   // we know the exact header size in most cases:
1712       BasicType elem = _igvn.type(klass_node)->is_klassptr()->as_instance_type()->isa_aryptr()->elem()->array_element_basic_type();
1713       if (is_reference_type(elem, true)) {
1714         elem = T_OBJECT;
1715       }
1716       header_size = Klass::layout_helper_header_size(Klass::array_layout_helper(elem));
1717     }
1718   }
1719 
1720   // Clear the object body, if necessary.
1721   if (init == nullptr) {
1722     // The init has somehow disappeared; be cautious and clear everything.
1723     //
1724     // This can happen if a node is allocated but an uncommon trap occurs
1725     // immediately.  In this case, the Initialize gets associated with the
1726     // trap, and may be placed in a different (outer) loop, if the Allocate
1727     // is in a loop.  If (this is rare) the inner loop gets unrolled, then
1728     // there can be two Allocates to one Initialize.  The answer in all these
1729     // edge cases is safety first.  It is always safe to clear immediately
1730     // within an Allocate, and then (maybe or maybe not) clear some more later.
1731     if (!(UseTLAB && ZeroTLAB)) {
1732       rawmem = ClearArrayNode::clear_memory(control, rawmem, object,
1733                                             header_size, size_in_bytes,
1734                                             &_igvn);
1735     }
1736   } else {
1737     if (!init->is_complete()) {
1738       // Try to win by zeroing only what the init does not store.
1739       // We can also try to do some peephole optimizations,
1740       // such as combining some adjacent subword stores.
1741       rawmem = init->complete_stores(control, rawmem, object,
1742                                      header_size, size_in_bytes, &_igvn);
1743     }
1744     // We have no more use for this link, since the AllocateNode goes away:
1745     init->set_req(InitializeNode::RawAddress, top());
1746     // (If we keep the link, it just confuses the register allocator,
1747     // who thinks he sees a real use of the address by the membar.)
1748   }
1749 
1750   return rawmem;
1751 }
1752 
1753 // Generate prefetch instructions for next allocations.
1754 Node* PhaseMacroExpand::prefetch_allocation(Node* i_o, Node*& needgc_false,
1755                                         Node*& contended_phi_rawmem,
1756                                         Node* old_eden_top, Node* new_eden_top,
1757                                         intx lines) {
1758    enum { fall_in_path = 1, pf_path = 2 };
1759    if( UseTLAB && AllocatePrefetchStyle == 2 ) {
1760       // Generate prefetch allocation with watermark check.
1761       // As an allocation hits the watermark, we will prefetch starting
1762       // at a "distance" away from watermark.
1763 
1764       Node *pf_region = new RegionNode(3);
1765       Node *pf_phi_rawmem = new PhiNode( pf_region, Type::MEMORY,
1766                                                 TypeRawPtr::BOTTOM );
1767       // I/O is used for Prefetch
1768       Node *pf_phi_abio = new PhiNode( pf_region, Type::ABIO );
1769 
1770       Node *thread = new ThreadLocalNode();
1771       transform_later(thread);
1772 
1773       Node *eden_pf_adr = new AddPNode( top()/*not oop*/, thread,
1774                    _igvn.MakeConX(in_bytes(JavaThread::tlab_pf_top_offset())) );
1775       transform_later(eden_pf_adr);
1776 
1777       Node *old_pf_wm = new LoadPNode(needgc_false,
1778                                    contended_phi_rawmem, eden_pf_adr,
1779                                    TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM,
1780                                    MemNode::unordered);
1781       transform_later(old_pf_wm);
1782 
1783       // check against new_eden_top
1784       Node *need_pf_cmp = new CmpPNode( new_eden_top, old_pf_wm );
1785       transform_later(need_pf_cmp);
1786       Node *need_pf_bol = new BoolNode( need_pf_cmp, BoolTest::ge );
1787       transform_later(need_pf_bol);
1788       IfNode *need_pf_iff = new IfNode( needgc_false, need_pf_bol,
1789                                        PROB_UNLIKELY_MAG(4), COUNT_UNKNOWN );
1790       transform_later(need_pf_iff);
1791 
1792       // true node, add prefetchdistance
1793       Node *need_pf_true = new IfTrueNode( need_pf_iff );
1794       transform_later(need_pf_true);
1795 
1796       Node *need_pf_false = new IfFalseNode( need_pf_iff );
1797       transform_later(need_pf_false);
1798 
1799       Node *new_pf_wmt = new AddPNode( top(), old_pf_wm,
1800                                     _igvn.MakeConX(AllocatePrefetchDistance) );
1801       transform_later(new_pf_wmt );
1802       new_pf_wmt->set_req(0, need_pf_true);
1803 
1804       Node *store_new_wmt = new StorePNode(need_pf_true,
1805                                        contended_phi_rawmem, eden_pf_adr,
1806                                        TypeRawPtr::BOTTOM, new_pf_wmt,
1807                                        MemNode::unordered);
1808       transform_later(store_new_wmt);
1809 
1810       // adding prefetches
1811       pf_phi_abio->init_req( fall_in_path, i_o );
1812 
1813       Node *prefetch_adr;
1814       Node *prefetch;
1815       uint step_size = AllocatePrefetchStepSize;
1816       uint distance = 0;
1817 
1818       for ( intx i = 0; i < lines; i++ ) {
1819         prefetch_adr = new AddPNode( old_pf_wm, new_pf_wmt,
1820                                             _igvn.MakeConX(distance) );
1821         transform_later(prefetch_adr);
1822         prefetch = new PrefetchAllocationNode( i_o, prefetch_adr );
1823         transform_later(prefetch);
1824         distance += step_size;
1825         i_o = prefetch;
1826       }
1827       pf_phi_abio->set_req( pf_path, i_o );
1828 
1829       pf_region->init_req( fall_in_path, need_pf_false );
1830       pf_region->init_req( pf_path, need_pf_true );
1831 
1832       pf_phi_rawmem->init_req( fall_in_path, contended_phi_rawmem );
1833       pf_phi_rawmem->init_req( pf_path, store_new_wmt );
1834 
1835       transform_later(pf_region);
1836       transform_later(pf_phi_rawmem);
1837       transform_later(pf_phi_abio);
1838 
1839       needgc_false = pf_region;
1840       contended_phi_rawmem = pf_phi_rawmem;
1841       i_o = pf_phi_abio;
1842    } else if( UseTLAB && AllocatePrefetchStyle == 3 ) {
1843       // Insert a prefetch instruction for each allocation.
1844       // This code is used to generate 1 prefetch instruction per cache line.
1845 
1846       // Generate several prefetch instructions.
1847       uint step_size = AllocatePrefetchStepSize;
1848       uint distance = AllocatePrefetchDistance;
1849 
1850       // Next cache address.
1851       Node *cache_adr = new AddPNode(old_eden_top, old_eden_top,
1852                                      _igvn.MakeConX(step_size + distance));
1853       transform_later(cache_adr);
1854       cache_adr = new CastP2XNode(needgc_false, cache_adr);
1855       transform_later(cache_adr);
1856       // Address is aligned to execute prefetch to the beginning of cache line size
1857       // (it is important when BIS instruction is used on SPARC as prefetch).
1858       Node* mask = _igvn.MakeConX(~(intptr_t)(step_size-1));
1859       cache_adr = new AndXNode(cache_adr, mask);
1860       transform_later(cache_adr);
1861       cache_adr = new CastX2PNode(cache_adr);
1862       transform_later(cache_adr);
1863 
1864       // Prefetch
1865       Node *prefetch = new PrefetchAllocationNode( contended_phi_rawmem, cache_adr );
1866       prefetch->set_req(0, needgc_false);
1867       transform_later(prefetch);
1868       contended_phi_rawmem = prefetch;
1869       Node *prefetch_adr;
1870       distance = step_size;
1871       for ( intx i = 1; i < lines; i++ ) {
1872         prefetch_adr = new AddPNode( cache_adr, cache_adr,
1873                                             _igvn.MakeConX(distance) );
1874         transform_later(prefetch_adr);
1875         prefetch = new PrefetchAllocationNode( contended_phi_rawmem, prefetch_adr );
1876         transform_later(prefetch);
1877         distance += step_size;
1878         contended_phi_rawmem = prefetch;
1879       }
1880    } else if( AllocatePrefetchStyle > 0 ) {
1881       // Insert a prefetch for each allocation only on the fast-path
1882       Node *prefetch_adr;
1883       Node *prefetch;
1884       // Generate several prefetch instructions.
1885       uint step_size = AllocatePrefetchStepSize;
1886       uint distance = AllocatePrefetchDistance;
1887       for ( intx i = 0; i < lines; i++ ) {
1888         prefetch_adr = new AddPNode( old_eden_top, new_eden_top,
1889                                             _igvn.MakeConX(distance) );
1890         transform_later(prefetch_adr);
1891         prefetch = new PrefetchAllocationNode( i_o, prefetch_adr );
1892         // Do not let it float too high, since if eden_top == eden_end,
1893         // both might be null.
1894         if( i == 0 ) { // Set control for first prefetch, next follows it
1895           prefetch->init_req(0, needgc_false);
1896         }
1897         transform_later(prefetch);
1898         distance += step_size;
1899         i_o = prefetch;
1900       }
1901    }
1902    return i_o;
1903 }
1904 
1905 
1906 void PhaseMacroExpand::expand_allocate(AllocateNode *alloc) {
1907   expand_allocate_common(alloc, nullptr,
1908                          OptoRuntime::new_instance_Type(),
1909                          OptoRuntime::new_instance_Java(), nullptr);
1910 }
1911 
1912 void PhaseMacroExpand::expand_allocate_array(AllocateArrayNode *alloc) {
1913   Node* length = alloc->in(AllocateNode::ALength);
1914   Node* valid_length_test = alloc->in(AllocateNode::ValidLengthTest);
1915   InitializeNode* init = alloc->initialization();
1916   Node* klass_node = alloc->in(AllocateNode::KlassNode);
1917   const TypeAryKlassPtr* ary_klass_t = _igvn.type(klass_node)->isa_aryklassptr();
1918   address slow_call_address;  // Address of slow call
1919   if (init != nullptr && init->is_complete_with_arraycopy() &&
1920       ary_klass_t && ary_klass_t->elem()->isa_klassptr() == nullptr) {
1921     // Don't zero type array during slow allocation in VM since
1922     // it will be initialized later by arraycopy in compiled code.
1923     slow_call_address = OptoRuntime::new_array_nozero_Java();
1924   } else {
1925     slow_call_address = OptoRuntime::new_array_Java();
1926   }
1927   expand_allocate_common(alloc, length,
1928                          OptoRuntime::new_array_Type(),
1929                          slow_call_address, valid_length_test);
1930 }
1931 
1932 //-------------------mark_eliminated_box----------------------------------
1933 //
1934 // During EA obj may point to several objects but after few ideal graph
1935 // transformations (CCP) it may point to only one non escaping object
1936 // (but still using phi), corresponding locks and unlocks will be marked
1937 // for elimination. Later obj could be replaced with a new node (new phi)
1938 // and which does not have escape information. And later after some graph
1939 // reshape other locks and unlocks (which were not marked for elimination
1940 // before) are connected to this new obj (phi) but they still will not be
1941 // marked for elimination since new obj has no escape information.
1942 // Mark all associated (same box and obj) lock and unlock nodes for
1943 // elimination if some of them marked already.
1944 void PhaseMacroExpand::mark_eliminated_box(Node* box, Node* obj) {
1945   BoxLockNode* oldbox = box->as_BoxLock();
1946   if (oldbox->is_eliminated()) {
1947     return; // This BoxLock node was processed already.
1948   }
1949   assert(!oldbox->is_unbalanced(), "this should not be called for unbalanced region");
1950   // New implementation (EliminateNestedLocks) has separate BoxLock
1951   // node for each locked region so mark all associated locks/unlocks as
1952   // eliminated even if different objects are referenced in one locked region
1953   // (for example, OSR compilation of nested loop inside locked scope).
1954   if (EliminateNestedLocks ||
1955       oldbox->as_BoxLock()->is_simple_lock_region(nullptr, obj, nullptr)) {
1956     // Box is used only in one lock region. Mark this box as eliminated.
1957     oldbox->set_local();      // This verifies correct state of BoxLock
1958     _igvn.hash_delete(oldbox);
1959     oldbox->set_eliminated(); // This changes box's hash value
1960      _igvn.hash_insert(oldbox);
1961 
1962     for (uint i = 0; i < oldbox->outcnt(); i++) {
1963       Node* u = oldbox->raw_out(i);
1964       if (u->is_AbstractLock() && !u->as_AbstractLock()->is_non_esc_obj()) {
1965         AbstractLockNode* alock = u->as_AbstractLock();
1966         // Check lock's box since box could be referenced by Lock's debug info.
1967         if (alock->box_node() == oldbox) {
1968           // Mark eliminated all related locks and unlocks.
1969 #ifdef ASSERT
1970           alock->log_lock_optimization(C, "eliminate_lock_set_non_esc4");
1971 #endif
1972           alock->set_non_esc_obj();
1973         }
1974       }
1975     }
1976     return;
1977   }
1978 
1979   // Create new "eliminated" BoxLock node and use it in monitor debug info
1980   // instead of oldbox for the same object.
1981   BoxLockNode* newbox = oldbox->clone()->as_BoxLock();
1982 
1983   // Note: BoxLock node is marked eliminated only here and it is used
1984   // to indicate that all associated lock and unlock nodes are marked
1985   // for elimination.
1986   newbox->set_local(); // This verifies correct state of BoxLock
1987   newbox->set_eliminated();
1988   transform_later(newbox);
1989 
1990   // Replace old box node with new box for all users of the same object.
1991   for (uint i = 0; i < oldbox->outcnt();) {
1992     bool next_edge = true;
1993 
1994     Node* u = oldbox->raw_out(i);
1995     if (u->is_AbstractLock()) {
1996       AbstractLockNode* alock = u->as_AbstractLock();
1997       if (alock->box_node() == oldbox && alock->obj_node()->eqv_uncast(obj)) {
1998         // Replace Box and mark eliminated all related locks and unlocks.
1999 #ifdef ASSERT
2000         alock->log_lock_optimization(C, "eliminate_lock_set_non_esc5");
2001 #endif
2002         alock->set_non_esc_obj();
2003         _igvn.rehash_node_delayed(alock);
2004         alock->set_box_node(newbox);
2005         next_edge = false;
2006       }
2007     }
2008     if (u->is_FastLock() && u->as_FastLock()->obj_node()->eqv_uncast(obj)) {
2009       FastLockNode* flock = u->as_FastLock();
2010       assert(flock->box_node() == oldbox, "sanity");
2011       _igvn.rehash_node_delayed(flock);
2012       flock->set_box_node(newbox);
2013       next_edge = false;
2014     }
2015 
2016     // Replace old box in monitor debug info.
2017     if (u->is_SafePoint() && u->as_SafePoint()->jvms()) {
2018       SafePointNode* sfn = u->as_SafePoint();
2019       JVMState* youngest_jvms = sfn->jvms();
2020       int max_depth = youngest_jvms->depth();
2021       for (int depth = 1; depth <= max_depth; depth++) {
2022         JVMState* jvms = youngest_jvms->of_depth(depth);
2023         int num_mon  = jvms->nof_monitors();
2024         // Loop over monitors
2025         for (int idx = 0; idx < num_mon; idx++) {
2026           Node* obj_node = sfn->monitor_obj(jvms, idx);
2027           Node* box_node = sfn->monitor_box(jvms, idx);
2028           if (box_node == oldbox && obj_node->eqv_uncast(obj)) {
2029             int j = jvms->monitor_box_offset(idx);
2030             _igvn.replace_input_of(u, j, newbox);
2031             next_edge = false;
2032           }
2033         }
2034       }
2035     }
2036     if (next_edge) i++;
2037   }
2038 }
2039 
2040 //-----------------------mark_eliminated_locking_nodes-----------------------
2041 void PhaseMacroExpand::mark_eliminated_locking_nodes(AbstractLockNode *alock) {
2042   if (!alock->is_balanced()) {
2043     return; // Can't do any more elimination for this locking region
2044   }
2045   if (EliminateNestedLocks) {
2046     if (alock->is_nested()) {
2047        assert(alock->box_node()->as_BoxLock()->is_eliminated(), "sanity");
2048        return;
2049     } else if (!alock->is_non_esc_obj()) { // Not eliminated or coarsened
2050       // Only Lock node has JVMState needed here.
2051       // Not that preceding claim is documented anywhere else.
2052       if (alock->jvms() != nullptr) {
2053         if (alock->as_Lock()->is_nested_lock_region()) {
2054           // Mark eliminated related nested locks and unlocks.
2055           Node* obj = alock->obj_node();
2056           BoxLockNode* box_node = alock->box_node()->as_BoxLock();
2057           assert(!box_node->is_eliminated(), "should not be marked yet");
2058           // Note: BoxLock node is marked eliminated only here
2059           // and it is used to indicate that all associated lock
2060           // and unlock nodes are marked for elimination.
2061           box_node->set_eliminated(); // Box's hash is always NO_HASH here
2062           for (uint i = 0; i < box_node->outcnt(); i++) {
2063             Node* u = box_node->raw_out(i);
2064             if (u->is_AbstractLock()) {
2065               alock = u->as_AbstractLock();
2066               if (alock->box_node() == box_node) {
2067                 // Verify that this Box is referenced only by related locks.
2068                 assert(alock->obj_node()->eqv_uncast(obj), "");
2069                 // Mark all related locks and unlocks.
2070 #ifdef ASSERT
2071                 alock->log_lock_optimization(C, "eliminate_lock_set_nested");
2072 #endif
2073                 alock->set_nested();
2074               }
2075             }
2076           }
2077         } else {
2078 #ifdef ASSERT
2079           alock->log_lock_optimization(C, "eliminate_lock_NOT_nested_lock_region");
2080           if (C->log() != nullptr)
2081             alock->as_Lock()->is_nested_lock_region(C); // rerun for debugging output
2082 #endif
2083         }
2084       }
2085       return;
2086     }
2087     // Process locks for non escaping object
2088     assert(alock->is_non_esc_obj(), "");
2089   } // EliminateNestedLocks
2090 
2091   if (alock->is_non_esc_obj()) { // Lock is used for non escaping object
2092     // Look for all locks of this object and mark them and
2093     // corresponding BoxLock nodes as eliminated.
2094     Node* obj = alock->obj_node();
2095     for (uint j = 0; j < obj->outcnt(); j++) {
2096       Node* o = obj->raw_out(j);
2097       if (o->is_AbstractLock() &&
2098           o->as_AbstractLock()->obj_node()->eqv_uncast(obj)) {
2099         alock = o->as_AbstractLock();
2100         Node* box = alock->box_node();
2101         // Replace old box node with new eliminated box for all users
2102         // of the same object and mark related locks as eliminated.
2103         mark_eliminated_box(box, obj);
2104       }
2105     }
2106   }
2107 }
2108 
2109 // we have determined that this lock/unlock can be eliminated, we simply
2110 // eliminate the node without expanding it.
2111 //
2112 // Note:  The membar's associated with the lock/unlock are currently not
2113 //        eliminated.  This should be investigated as a future enhancement.
2114 //
2115 bool PhaseMacroExpand::eliminate_locking_node(AbstractLockNode *alock) {
2116 
2117   if (!alock->is_eliminated()) {
2118     return false;
2119   }
2120 #ifdef ASSERT
2121   if (!alock->is_coarsened()) {
2122     // Check that new "eliminated" BoxLock node is created.
2123     BoxLockNode* oldbox = alock->box_node()->as_BoxLock();
2124     assert(oldbox->is_eliminated(), "should be done already");
2125   }
2126 #endif
2127 
2128   alock->log_lock_optimization(C, "eliminate_lock");
2129 
2130 #ifndef PRODUCT
2131   if (PrintEliminateLocks) {
2132     tty->print_cr("++++ Eliminated: %d %s '%s'", alock->_idx, (alock->is_Lock() ? "Lock" : "Unlock"), alock->kind_as_string());
2133   }
2134 #endif
2135 
2136   Node* mem  = alock->in(TypeFunc::Memory);
2137   Node* ctrl = alock->in(TypeFunc::Control);
2138   guarantee(ctrl != nullptr, "missing control projection, cannot replace_node() with null");
2139 
2140   alock->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2141   // There are 2 projections from the lock.  The lock node will
2142   // be deleted when its last use is subsumed below.
2143   assert(alock->outcnt() == 2 &&
2144          _callprojs.fallthrough_proj != nullptr &&
2145          _callprojs.fallthrough_memproj != nullptr,
2146          "Unexpected projections from Lock/Unlock");
2147 
2148   Node* fallthroughproj = _callprojs.fallthrough_proj;
2149   Node* memproj_fallthrough = _callprojs.fallthrough_memproj;
2150 
2151   // The memory projection from a lock/unlock is RawMem
2152   // The input to a Lock is merged memory, so extract its RawMem input
2153   // (unless the MergeMem has been optimized away.)
2154   if (alock->is_Lock()) {
2155     // Search for MemBarAcquireLock node and delete it also.
2156     MemBarNode* membar = fallthroughproj->unique_ctrl_out()->as_MemBar();
2157     assert(membar != nullptr && membar->Opcode() == Op_MemBarAcquireLock, "");
2158     Node* ctrlproj = membar->proj_out(TypeFunc::Control);
2159     Node* memproj = membar->proj_out(TypeFunc::Memory);
2160     _igvn.replace_node(ctrlproj, fallthroughproj);
2161     _igvn.replace_node(memproj, memproj_fallthrough);
2162 
2163     // Delete FastLock node also if this Lock node is unique user
2164     // (a loop peeling may clone a Lock node).
2165     Node* flock = alock->as_Lock()->fastlock_node();
2166     if (flock->outcnt() == 1) {
2167       assert(flock->unique_out() == alock, "sanity");
2168       _igvn.replace_node(flock, top());
2169     }
2170   }
2171 
2172   // Search for MemBarReleaseLock node and delete it also.
2173   if (alock->is_Unlock() && ctrl->is_Proj() && ctrl->in(0)->is_MemBar()) {
2174     MemBarNode* membar = ctrl->in(0)->as_MemBar();
2175     assert(membar->Opcode() == Op_MemBarReleaseLock &&
2176            mem->is_Proj() && membar == mem->in(0), "");
2177     _igvn.replace_node(fallthroughproj, ctrl);
2178     _igvn.replace_node(memproj_fallthrough, mem);
2179     fallthroughproj = ctrl;
2180     memproj_fallthrough = mem;
2181     ctrl = membar->in(TypeFunc::Control);
2182     mem  = membar->in(TypeFunc::Memory);
2183   }
2184 
2185   _igvn.replace_node(fallthroughproj, ctrl);
2186   _igvn.replace_node(memproj_fallthrough, mem);
2187   return true;
2188 }
2189 
2190 
2191 //------------------------------expand_lock_node----------------------
2192 void PhaseMacroExpand::expand_lock_node(LockNode *lock) {
2193 
2194   Node* ctrl = lock->in(TypeFunc::Control);
2195   Node* mem = lock->in(TypeFunc::Memory);
2196   Node* obj = lock->obj_node();
2197   Node* box = lock->box_node();
2198   Node* flock = lock->fastlock_node();
2199 
2200   assert(!box->as_BoxLock()->is_eliminated(), "sanity");
2201 
2202   // Make the merge point
2203   Node *region;
2204   Node *mem_phi;
2205   Node *slow_path;
2206 
2207   region  = new RegionNode(3);
2208   // create a Phi for the memory state
2209   mem_phi = new PhiNode( region, Type::MEMORY, TypeRawPtr::BOTTOM);
2210 
2211   // Optimize test; set region slot 2
2212   slow_path = opt_bits_test(ctrl, region, 2, flock);
2213   mem_phi->init_req(2, mem);
2214 
2215   // Make slow path call
2216   CallNode* call = make_slow_call(lock, OptoRuntime::complete_monitor_enter_Type(),
2217                                   OptoRuntime::complete_monitor_locking_Java(), nullptr, slow_path,
2218                                   obj, box, nullptr);
2219 
2220   call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2221 
2222   // Slow path can only throw asynchronous exceptions, which are always
2223   // de-opted.  So the compiler thinks the slow-call can never throw an
2224   // exception.  If it DOES throw an exception we would need the debug
2225   // info removed first (since if it throws there is no monitor).
2226   assert(_callprojs.fallthrough_ioproj == nullptr && _callprojs.catchall_ioproj == nullptr &&
2227          _callprojs.catchall_memproj == nullptr && _callprojs.catchall_catchproj == nullptr, "Unexpected projection from Lock");
2228 
2229   // Capture slow path
2230   // disconnect fall-through projection from call and create a new one
2231   // hook up users of fall-through projection to region
2232   Node *slow_ctrl = _callprojs.fallthrough_proj->clone();
2233   transform_later(slow_ctrl);
2234   _igvn.hash_delete(_callprojs.fallthrough_proj);
2235   _callprojs.fallthrough_proj->disconnect_inputs(C);
2236   region->init_req(1, slow_ctrl);
2237   // region inputs are now complete
2238   transform_later(region);
2239   _igvn.replace_node(_callprojs.fallthrough_proj, region);
2240 
2241   Node *memproj = transform_later(new ProjNode(call, TypeFunc::Memory));
2242 
2243   mem_phi->init_req(1, memproj);
2244 
2245   transform_later(mem_phi);
2246 
2247   _igvn.replace_node(_callprojs.fallthrough_memproj, mem_phi);
2248 }
2249 
2250 //------------------------------expand_unlock_node----------------------
2251 void PhaseMacroExpand::expand_unlock_node(UnlockNode *unlock) {
2252 
2253   Node* ctrl = unlock->in(TypeFunc::Control);
2254   Node* mem = unlock->in(TypeFunc::Memory);
2255   Node* obj = unlock->obj_node();
2256   Node* box = unlock->box_node();
2257 
2258   assert(!box->as_BoxLock()->is_eliminated(), "sanity");
2259 
2260   // No need for a null check on unlock
2261 
2262   // Make the merge point
2263   Node *region;
2264   Node *mem_phi;
2265 
2266   region  = new RegionNode(3);
2267   // create a Phi for the memory state
2268   mem_phi = new PhiNode( region, Type::MEMORY, TypeRawPtr::BOTTOM);
2269 
2270   FastUnlockNode *funlock = new FastUnlockNode( ctrl, obj, box );
2271   funlock = transform_later( funlock )->as_FastUnlock();
2272   // Optimize test; set region slot 2
2273   Node *slow_path = opt_bits_test(ctrl, region, 2, funlock);
2274   Node *thread = transform_later(new ThreadLocalNode());
2275 
2276   CallNode *call = make_slow_call((CallNode *) unlock, OptoRuntime::complete_monitor_exit_Type(),
2277                                   CAST_FROM_FN_PTR(address, SharedRuntime::complete_monitor_unlocking_C),
2278                                   "complete_monitor_unlocking_C", slow_path, obj, box, thread);
2279 
2280   call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2281   assert(_callprojs.fallthrough_ioproj == nullptr && _callprojs.catchall_ioproj == nullptr &&
2282          _callprojs.catchall_memproj == nullptr && _callprojs.catchall_catchproj == nullptr, "Unexpected projection from Lock");
2283 
2284   // No exceptions for unlocking
2285   // Capture slow path
2286   // disconnect fall-through projection from call and create a new one
2287   // hook up users of fall-through projection to region
2288   Node *slow_ctrl = _callprojs.fallthrough_proj->clone();
2289   transform_later(slow_ctrl);
2290   _igvn.hash_delete(_callprojs.fallthrough_proj);
2291   _callprojs.fallthrough_proj->disconnect_inputs(C);
2292   region->init_req(1, slow_ctrl);
2293   // region inputs are now complete
2294   transform_later(region);
2295   _igvn.replace_node(_callprojs.fallthrough_proj, region);
2296 
2297   Node *memproj = transform_later(new ProjNode(call, TypeFunc::Memory) );
2298   mem_phi->init_req(1, memproj );
2299   mem_phi->init_req(2, mem);
2300   transform_later(mem_phi);
2301 
2302   _igvn.replace_node(_callprojs.fallthrough_memproj, mem_phi);
2303 }
2304 
2305 void PhaseMacroExpand::expand_subtypecheck_node(SubTypeCheckNode *check) {
2306   assert(check->in(SubTypeCheckNode::Control) == nullptr, "should be pinned");
2307   Node* bol = check->unique_out();
2308   Node* obj_or_subklass = check->in(SubTypeCheckNode::ObjOrSubKlass);
2309   Node* superklass = check->in(SubTypeCheckNode::SuperKlass);
2310   assert(bol->is_Bool() && bol->as_Bool()->_test._test == BoolTest::ne, "unexpected bool node");
2311 
2312   for (DUIterator_Last imin, i = bol->last_outs(imin); i >= imin; --i) {
2313     Node* iff = bol->last_out(i);
2314     assert(iff->is_If(), "where's the if?");
2315 
2316     if (iff->in(0)->is_top()) {
2317       _igvn.replace_input_of(iff, 1, C->top());
2318       continue;
2319     }
2320 
2321     Node* iftrue = iff->as_If()->proj_out(1);
2322     Node* iffalse = iff->as_If()->proj_out(0);
2323     Node* ctrl = iff->in(0);
2324 
2325     Node* subklass = nullptr;
2326     if (_igvn.type(obj_or_subklass)->isa_klassptr()) {
2327       subklass = obj_or_subklass;
2328     } else {
2329       Node* k_adr = basic_plus_adr(obj_or_subklass, Type::klass_offset());
2330       subklass = _igvn.transform(LoadKlassNode::make(_igvn, C->immutable_memory(), k_adr, TypeInstPtr::KLASS));
2331     }
2332 
2333     Node* not_subtype_ctrl = Phase::gen_subtype_check(subklass, superklass, &ctrl, nullptr, _igvn, check->method(), check->bci());
2334 
2335     _igvn.replace_input_of(iff, 0, C->top());
2336     _igvn.replace_node(iftrue, not_subtype_ctrl);
2337     _igvn.replace_node(iffalse, ctrl);
2338   }
2339   _igvn.replace_node(check, C->top());
2340 }
2341 
2342 // Perform refining of strip mined loop nodes in the macro nodes list.
2343 void PhaseMacroExpand::refine_strip_mined_loop_macro_nodes() {
2344    for (int i = C->macro_count(); i > 0; i--) {
2345     Node* n = C->macro_node(i - 1);
2346     if (n->is_OuterStripMinedLoop()) {
2347       n->as_OuterStripMinedLoop()->adjust_strip_mined_loop(&_igvn);
2348     }
2349   }
2350 }
2351 
2352 //---------------------------eliminate_macro_nodes----------------------
2353 // Eliminate scalar replaced allocations and associated locks.
2354 void PhaseMacroExpand::eliminate_macro_nodes() {
2355   if (C->macro_count() == 0)
2356     return;
2357 
2358   if (StressMacroElimination) {
2359     C->shuffle_macro_nodes();
2360   }
2361   NOT_PRODUCT(int membar_before = count_MemBar(C);)
2362 
2363   // Before elimination may re-mark (change to Nested or NonEscObj)
2364   // all associated (same box and obj) lock and unlock nodes.
2365   int cnt = C->macro_count();
2366   for (int i=0; i < cnt; i++) {
2367     Node *n = C->macro_node(i);
2368     if (n->is_AbstractLock()) { // Lock and Unlock nodes
2369       mark_eliminated_locking_nodes(n->as_AbstractLock());
2370     }
2371   }
2372   // Re-marking may break consistency of Coarsened locks.
2373   if (!C->coarsened_locks_consistent()) {
2374     return; // recompile without Coarsened locks if broken
2375   } else {
2376     // After coarsened locks are eliminated locking regions
2377     // become unbalanced. We should not execute any more
2378     // locks elimination optimizations on them.
2379     C->mark_unbalanced_boxes();
2380   }
2381 
2382   // First, attempt to eliminate locks
2383   bool progress = true;
2384   while (progress) {
2385     progress = false;
2386     for (int i = C->macro_count(); i > 0; i = MIN2(i - 1, C->macro_count())) { // more than 1 element can be eliminated at once
2387       Node* n = C->macro_node(i - 1);
2388       bool success = false;
2389       DEBUG_ONLY(int old_macro_count = C->macro_count();)
2390       if (n->is_AbstractLock()) {
2391         success = eliminate_locking_node(n->as_AbstractLock());
2392 #ifndef PRODUCT
2393         if (success && PrintOptoStatistics) {
2394           Atomic::inc(&PhaseMacroExpand::_monitor_objects_removed_counter);
2395         }
2396 #endif
2397       }
2398       assert(success == (C->macro_count() < old_macro_count), "elimination reduces macro count");
2399       progress = progress || success;
2400       if (success) {
2401         C->print_method(PHASE_AFTER_MACRO_ELIMINATION_STEP, 5, n);
2402       }
2403     }
2404   }
2405   // Next, attempt to eliminate allocations
2406   progress = true;
2407   while (progress) {
2408     progress = false;
2409     for (int i = C->macro_count(); i > 0; i = MIN2(i - 1, C->macro_count())) { // more than 1 element can be eliminated at once
2410       Node* n = C->macro_node(i - 1);
2411       bool success = false;
2412       DEBUG_ONLY(int old_macro_count = C->macro_count();)
2413       switch (n->class_id()) {
2414       case Node::Class_Allocate:
2415       case Node::Class_AllocateArray:
2416         success = eliminate_allocate_node(n->as_Allocate());
2417 #ifndef PRODUCT
2418         if (success && PrintOptoStatistics) {
2419           Atomic::inc(&PhaseMacroExpand::_objs_scalar_replaced_counter);
2420         }
2421 #endif
2422         break;
2423       case Node::Class_CallStaticJava:
2424         success = eliminate_boxing_node(n->as_CallStaticJava());
2425         break;
2426       case Node::Class_Lock:
2427       case Node::Class_Unlock:
2428         assert(!n->as_AbstractLock()->is_eliminated(), "sanity");
2429         break;
2430       case Node::Class_ArrayCopy:
2431         break;
2432       case Node::Class_OuterStripMinedLoop:
2433         break;
2434       case Node::Class_SubTypeCheck:
2435         break;
2436       case Node::Class_Opaque1:
2437         break;
2438       default:
2439         assert(n->Opcode() == Op_LoopLimit ||
2440                n->Opcode() == Op_ModD ||
2441                n->Opcode() == Op_ModF ||
2442                n->is_OpaqueNotNull()       ||
2443                n->is_OpaqueInitializedAssertionPredicate() ||
2444                n->Opcode() == Op_MaxL      ||
2445                n->Opcode() == Op_MinL      ||
2446                BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(n),
2447                "unknown node type in macro list");
2448       }
2449       assert(success == (C->macro_count() < old_macro_count), "elimination reduces macro count");
2450       progress = progress || success;
2451       if (success) {
2452         C->print_method(PHASE_AFTER_MACRO_ELIMINATION_STEP, 5, n);
2453       }
2454     }
2455   }
2456 #ifndef PRODUCT
2457   if (PrintOptoStatistics) {
2458     int membar_after = count_MemBar(C);
2459     Atomic::add(&PhaseMacroExpand::_memory_barriers_removed_counter, membar_before - membar_after);
2460   }
2461 #endif
2462 }
2463 
2464 void PhaseMacroExpand::eliminate_opaque_looplimit_macro_nodes() {
2465   if (C->macro_count() == 0) {
2466     return;
2467   }
2468   refine_strip_mined_loop_macro_nodes();
2469   // Eliminate Opaque and LoopLimit nodes. Do it after all loop optimizations.
2470   bool progress = true;
2471   while (progress) {
2472     progress = false;
2473     for (int i = C->macro_count(); i > 0; i--) {
2474       Node* n = C->macro_node(i-1);
2475       bool success = false;
2476       DEBUG_ONLY(int old_macro_count = C->macro_count();)
2477       if (n->Opcode() == Op_LoopLimit) {
2478         // Remove it from macro list and put on IGVN worklist to optimize.
2479         C->remove_macro_node(n);
2480         _igvn._worklist.push(n);
2481         success = true;
2482       } else if (n->Opcode() == Op_CallStaticJava) {
2483         // Remove it from macro list and put on IGVN worklist to optimize.
2484         C->remove_macro_node(n);
2485         _igvn._worklist.push(n);
2486         success = true;
2487       } else if (n->is_Opaque1()) {
2488         _igvn.replace_node(n, n->in(1));
2489         success = true;
2490       } else if (n->is_OpaqueNotNull()) {
2491         // Tests with OpaqueNotNull nodes are implicitly known to be true. Replace the node with true. In debug builds,
2492         // we leave the test in the graph to have an additional sanity check at runtime. If the test fails (i.e. a bug),
2493         // we will execute a Halt node.
2494 #ifdef ASSERT
2495         _igvn.replace_node(n, n->in(1));
2496 #else
2497         _igvn.replace_node(n, _igvn.intcon(1));
2498 #endif
2499         success = true;
2500       } else if (n->is_OpaqueInitializedAssertionPredicate()) {
2501           // Initialized Assertion Predicates must always evaluate to true. Therefore, we get rid of them in product
2502           // builds as they are useless. In debug builds we keep them as additional verification code. Even though
2503           // loop opts are already over, we want to keep Initialized Assertion Predicates alive as long as possible to
2504           // enable folding of dead control paths within which cast nodes become top after due to impossible types -
2505           // even after loop opts are over. Therefore, we delay the removal of these opaque nodes until now.
2506 #ifdef ASSERT
2507         _igvn.replace_node(n, n->in(1));
2508 #else
2509         _igvn.replace_node(n, _igvn.intcon(1));
2510 #endif // ASSERT
2511       } else if (n->Opcode() == Op_OuterStripMinedLoop) {
2512         C->remove_macro_node(n);
2513         success = true;
2514       } else if (n->Opcode() == Op_MaxL) {
2515         // Since MaxL and MinL are not implemented in the backend, we expand them to
2516         // a CMoveL construct now. At least until here, the type could be computed
2517         // precisely. CMoveL is not so smart, but we can give it at least the best
2518         // type we know abouot n now.
2519         Node* repl = MaxNode::signed_max(n->in(1), n->in(2), _igvn.type(n), _igvn);
2520         _igvn.replace_node(n, repl);
2521         success = true;
2522       } else if (n->Opcode() == Op_MinL) {
2523         Node* repl = MaxNode::signed_min(n->in(1), n->in(2), _igvn.type(n), _igvn);
2524         _igvn.replace_node(n, repl);
2525         success = true;
2526       }
2527       assert(!success || (C->macro_count() == (old_macro_count - 1)), "elimination must have deleted one node from macro list");
2528       progress = progress || success;
2529       if (success) {
2530         C->print_method(PHASE_AFTER_MACRO_ELIMINATION_STEP, 5, n);
2531       }
2532     }
2533   }
2534 }
2535 
2536 //------------------------------expand_macro_nodes----------------------
2537 //  Returns true if a failure occurred.
2538 bool PhaseMacroExpand::expand_macro_nodes() {
2539   if (StressMacroExpansion) {
2540     C->shuffle_macro_nodes();
2541   }
2542 
2543   // Clean up the graph so we're less likely to hit the maximum node
2544   // limit
2545   _igvn.set_delay_transform(false);
2546   _igvn.optimize();
2547   if (C->failing())  return true;
2548   _igvn.set_delay_transform(true);
2549 
2550 
2551   // Because we run IGVN after each expansion, some macro nodes may go
2552   // dead and be removed from the list as we iterate over it. Move
2553   // Allocate nodes (processed in a second pass) at the beginning of
2554   // the list and then iterate from the last element of the list until
2555   // an Allocate node is seen. This is robust to random deletion in
2556   // the list due to nodes going dead.
2557   C->sort_macro_nodes();
2558 
2559   // expand arraycopy "macro" nodes first
2560   // For ReduceBulkZeroing, we must first process all arraycopy nodes
2561   // before the allocate nodes are expanded.
2562   while (C->macro_count() > 0) {
2563     int macro_count = C->macro_count();
2564     Node * n = C->macro_node(macro_count-1);
2565     assert(n->is_macro(), "only macro nodes expected here");
2566     if (_igvn.type(n) == Type::TOP || (n->in(0) != nullptr && n->in(0)->is_top())) {
2567       // node is unreachable, so don't try to expand it
2568       C->remove_macro_node(n);
2569       continue;
2570     }
2571     if (n->is_Allocate()) {
2572       break;
2573     }
2574     // Make sure expansion will not cause node limit to be exceeded.
2575     // Worst case is a macro node gets expanded into about 200 nodes.
2576     // Allow 50% more for optimization.
2577     if (C->check_node_count(300, "out of nodes before macro expansion")) {
2578       return true;
2579     }
2580 
2581     DEBUG_ONLY(int old_macro_count = C->macro_count();)
2582     switch (n->class_id()) {
2583     case Node::Class_Lock:
2584       expand_lock_node(n->as_Lock());
2585       break;
2586     case Node::Class_Unlock:
2587       expand_unlock_node(n->as_Unlock());
2588       break;
2589     case Node::Class_ArrayCopy:
2590       expand_arraycopy_node(n->as_ArrayCopy());
2591       break;
2592     case Node::Class_SubTypeCheck:
2593       expand_subtypecheck_node(n->as_SubTypeCheck());
2594       break;
2595     default:
2596       switch (n->Opcode()) {
2597       case Op_ModD:
2598       case Op_ModF: {
2599         bool is_drem = n->Opcode() == Op_ModD;
2600         CallNode* mod_macro = n->as_Call();
2601         CallNode* call = new CallLeafNode(mod_macro->tf(),
2602                                           is_drem ? CAST_FROM_FN_PTR(address, SharedRuntime::drem)
2603                                                   : CAST_FROM_FN_PTR(address, SharedRuntime::frem),
2604                                           is_drem ? "drem" : "frem", TypeRawPtr::BOTTOM);
2605         call->init_req(TypeFunc::Control, mod_macro->in(TypeFunc::Control));
2606         call->init_req(TypeFunc::I_O, mod_macro->in(TypeFunc::I_O));
2607         call->init_req(TypeFunc::Memory, mod_macro->in(TypeFunc::Memory));
2608         call->init_req(TypeFunc::ReturnAdr, mod_macro->in(TypeFunc::ReturnAdr));
2609         call->init_req(TypeFunc::FramePtr, mod_macro->in(TypeFunc::FramePtr));
2610         for (unsigned int i = 0; i < mod_macro->tf()->domain()->cnt() - TypeFunc::Parms; i++) {
2611           call->init_req(TypeFunc::Parms + i, mod_macro->in(TypeFunc::Parms + i));
2612         }
2613         _igvn.replace_node(mod_macro, call);
2614         transform_later(call);
2615         break;
2616       }
2617       default:
2618         assert(false, "unknown node type in macro list");
2619       }
2620     }
2621     assert(C->macro_count() == (old_macro_count - 1), "expansion must have deleted one node from macro list");
2622     if (C->failing())  return true;
2623     C->print_method(PHASE_AFTER_MACRO_EXPANSION_STEP, 5, n);
2624 
2625     // Clean up the graph so we're less likely to hit the maximum node
2626     // limit
2627     _igvn.set_delay_transform(false);
2628     _igvn.optimize();
2629     if (C->failing())  return true;
2630     _igvn.set_delay_transform(true);
2631   }
2632 
2633   // All nodes except Allocate nodes are expanded now. There could be
2634   // new optimization opportunities (such as folding newly created
2635   // load from a just allocated object). Run IGVN.
2636 
2637   // expand "macro" nodes
2638   // nodes are removed from the macro list as they are processed
2639   while (C->macro_count() > 0) {
2640     int macro_count = C->macro_count();
2641     Node * n = C->macro_node(macro_count-1);
2642     assert(n->is_macro(), "only macro nodes expected here");
2643     if (_igvn.type(n) == Type::TOP || (n->in(0) != nullptr && n->in(0)->is_top())) {
2644       // node is unreachable, so don't try to expand it
2645       C->remove_macro_node(n);
2646       continue;
2647     }
2648     // Make sure expansion will not cause node limit to be exceeded.
2649     // Worst case is a macro node gets expanded into about 200 nodes.
2650     // Allow 50% more for optimization.
2651     if (C->check_node_count(300, "out of nodes before macro expansion")) {
2652       return true;
2653     }
2654     switch (n->class_id()) {
2655     case Node::Class_Allocate:
2656       expand_allocate(n->as_Allocate());
2657       break;
2658     case Node::Class_AllocateArray:
2659       expand_allocate_array(n->as_AllocateArray());
2660       break;
2661     default:
2662       assert(false, "unknown node type in macro list");
2663     }
2664     assert(C->macro_count() < macro_count, "must have deleted a node from macro list");
2665     if (C->failing())  return true;
2666     C->print_method(PHASE_AFTER_MACRO_EXPANSION_STEP, 5, n);
2667 
2668     // Clean up the graph so we're less likely to hit the maximum node
2669     // limit
2670     _igvn.set_delay_transform(false);
2671     _igvn.optimize();
2672     if (C->failing())  return true;
2673     _igvn.set_delay_transform(true);
2674   }
2675 
2676   _igvn.set_delay_transform(false);
2677   return false;
2678 }
2679 
2680 #ifndef PRODUCT
2681 int PhaseMacroExpand::_objs_scalar_replaced_counter = 0;
2682 int PhaseMacroExpand::_monitor_objects_removed_counter = 0;
2683 int PhaseMacroExpand::_GC_barriers_removed_counter = 0;
2684 int PhaseMacroExpand::_memory_barriers_removed_counter = 0;
2685 
2686 void PhaseMacroExpand::print_statistics() {
2687   tty->print("Objects scalar replaced = %d, ", Atomic::load(&_objs_scalar_replaced_counter));
2688   tty->print("Monitor objects removed = %d, ", Atomic::load(&_monitor_objects_removed_counter));
2689   tty->print("GC barriers removed = %d, ", Atomic::load(&_GC_barriers_removed_counter));
2690   tty->print_cr("Memory barriers removed = %d", Atomic::load(&_memory_barriers_removed_counter));
2691 }
2692 
2693 int PhaseMacroExpand::count_MemBar(Compile *C) {
2694   if (!PrintOptoStatistics) {
2695     return 0;
2696   }
2697   Unique_Node_List ideal_nodes;
2698   int total = 0;
2699   ideal_nodes.map(C->live_nodes(), nullptr);
2700   ideal_nodes.push(C->root());
2701   for (uint next = 0; next < ideal_nodes.size(); ++next) {
2702     Node* n = ideal_nodes.at(next);
2703     if (n->is_MemBar()) {
2704       total++;
2705     }
2706     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2707       Node* m = n->fast_out(i);
2708       ideal_nodes.push(m);
2709     }
2710   }
2711   return total;
2712 }
2713 #endif