1 /*
   2  * Copyright (c) 2005, 2025, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "ci/bcEscapeAnalyzer.hpp"
  26 #include "compiler/compileLog.hpp"
  27 #include "gc/shared/barrierSet.hpp"
  28 #include "gc/shared/c2/barrierSetC2.hpp"
  29 #include "libadt/vectset.hpp"
  30 #include "memory/allocation.hpp"
  31 #include "memory/metaspace.hpp"
  32 #include "memory/resourceArea.hpp"
  33 #include "opto/c2compiler.hpp"
  34 #include "opto/arraycopynode.hpp"
  35 #include "opto/callnode.hpp"
  36 #include "opto/cfgnode.hpp"
  37 #include "opto/compile.hpp"
  38 #include "opto/escape.hpp"
  39 #include "opto/inlinetypenode.hpp"
  40 #include "opto/macro.hpp"
  41 #include "opto/locknode.hpp"
  42 #include "opto/phaseX.hpp"
  43 #include "opto/movenode.hpp"
  44 #include "opto/narrowptrnode.hpp"
  45 #include "opto/castnode.hpp"
  46 #include "opto/rootnode.hpp"
  47 #include "utilities/macros.hpp"
  48 
  49 ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn, int invocation) :
  50   // If ReduceAllocationMerges is enabled we might call split_through_phi during
  51   // split_unique_types and that will create additional nodes that need to be
  52   // pushed to the ConnectionGraph. The code below bumps the initial capacity of
  53   // _nodes by 10% to account for these additional nodes. If capacity is exceeded
  54   // the array will be reallocated.
  55   _nodes(C->comp_arena(), C->do_reduce_allocation_merges() ? C->unique()*1.10 : C->unique(), C->unique(), nullptr),
  56   _in_worklist(C->comp_arena()),
  57   _next_pidx(0),
  58   _collecting(true),
  59   _verify(false),
  60   _compile(C),
  61   _igvn(igvn),
  62   _invocation(invocation),
  63   _build_iterations(0),
  64   _build_time(0.),
  65   _node_map(C->comp_arena()) {
  66   // Add unknown java object.
  67   add_java_object(C->top(), PointsToNode::GlobalEscape);
  68   phantom_obj = ptnode_adr(C->top()->_idx)->as_JavaObject();
  69   set_not_scalar_replaceable(phantom_obj NOT_PRODUCT(COMMA "Phantom object"));
  70   // Add ConP and ConN null oop nodes
  71   Node* oop_null = igvn->zerocon(T_OBJECT);
  72   assert(oop_null->_idx < nodes_size(), "should be created already");
  73   add_java_object(oop_null, PointsToNode::NoEscape);
  74   null_obj = ptnode_adr(oop_null->_idx)->as_JavaObject();
  75   set_not_scalar_replaceable(null_obj NOT_PRODUCT(COMMA "Null object"));
  76   if (UseCompressedOops) {
  77     Node* noop_null = igvn->zerocon(T_NARROWOOP);
  78     assert(noop_null->_idx < nodes_size(), "should be created already");
  79     map_ideal_node(noop_null, null_obj);
  80   }
  81 }
  82 
  83 bool ConnectionGraph::has_candidates(Compile *C) {
  84   // EA brings benefits only when the code has allocations and/or locks which
  85   // are represented by ideal Macro nodes.
  86   int cnt = C->macro_count();
  87   for (int i = 0; i < cnt; i++) {
  88     Node *n = C->macro_node(i);
  89     if (n->is_Allocate()) {
  90       return true;
  91     }
  92     if (n->is_Lock()) {
  93       Node* obj = n->as_Lock()->obj_node()->uncast();
  94       if (!(obj->is_Parm() || obj->is_Con())) {
  95         return true;
  96       }
  97     }
  98     if (n->is_CallStaticJava() &&
  99         n->as_CallStaticJava()->is_boxing_method()) {
 100       return true;
 101     }
 102   }
 103   return false;
 104 }
 105 
 106 void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {
 107   Compile::TracePhase tp(Phase::_t_escapeAnalysis);
 108   ResourceMark rm;
 109 
 110   // Add ConP and ConN null oop nodes before ConnectionGraph construction
 111   // to create space for them in ConnectionGraph::_nodes[].
 112   Node* oop_null = igvn->zerocon(T_OBJECT);
 113   Node* noop_null = igvn->zerocon(T_NARROWOOP);
 114   int invocation = 0;
 115   if (C->congraph() != nullptr) {
 116     invocation = C->congraph()->_invocation + 1;
 117   }
 118   ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn, invocation);
 119   // Perform escape analysis
 120   if (congraph->compute_escape()) {
 121     // There are non escaping objects.
 122     C->set_congraph(congraph);
 123   }
 124   // Cleanup.
 125   if (oop_null->outcnt() == 0) {
 126     igvn->hash_delete(oop_null);
 127   }
 128   if (noop_null->outcnt() == 0) {
 129     igvn->hash_delete(noop_null);
 130   }
 131 }
 132 
 133 bool ConnectionGraph::compute_escape() {
 134   Compile* C = _compile;
 135   PhaseGVN* igvn = _igvn;
 136 
 137   // Worklists used by EA.
 138   Unique_Node_List delayed_worklist;
 139   Unique_Node_List reducible_merges;
 140   GrowableArray<Node*> alloc_worklist;
 141   GrowableArray<Node*> ptr_cmp_worklist;
 142   GrowableArray<MemBarStoreStoreNode*> storestore_worklist;
 143   GrowableArray<ArrayCopyNode*>  arraycopy_worklist;
 144   GrowableArray<PointsToNode*>   ptnodes_worklist;
 145   GrowableArray<JavaObjectNode*> java_objects_worklist;
 146   GrowableArray<JavaObjectNode*> non_escaped_allocs_worklist;
 147   GrowableArray<FieldNode*>      oop_fields_worklist;
 148   GrowableArray<SafePointNode*>  sfn_worklist;
 149   GrowableArray<MergeMemNode*>   mergemem_worklist;
 150   DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
 151 
 152   { Compile::TracePhase tp(Phase::_t_connectionGraph);
 153 
 154   // 1. Populate Connection Graph (CG) with PointsTo nodes.
 155   ideal_nodes.map(C->live_nodes(), nullptr);  // preallocate space
 156   // Initialize worklist
 157   if (C->root() != nullptr) {
 158     ideal_nodes.push(C->root());
 159   }
 160   // Processed ideal nodes are unique on ideal_nodes list
 161   // but several ideal nodes are mapped to the phantom_obj.
 162   // To avoid duplicated entries on the following worklists
 163   // add the phantom_obj only once to them.
 164   ptnodes_worklist.append(phantom_obj);
 165   java_objects_worklist.append(phantom_obj);
 166   for( uint next = 0; next < ideal_nodes.size(); ++next ) {
 167     Node* n = ideal_nodes.at(next);
 168     if ((n->Opcode() == Op_LoadX || n->Opcode() == Op_StoreX) &&
 169         !n->in(MemNode::Address)->is_AddP() &&
 170         _igvn->type(n->in(MemNode::Address))->isa_oopptr()) {
 171       // Load/Store at mark work address is at offset 0 so has no AddP which confuses EA
 172       Node* addp = new AddPNode(n->in(MemNode::Address), n->in(MemNode::Address), _igvn->MakeConX(0));
 173       _igvn->register_new_node_with_optimizer(addp);
 174       _igvn->replace_input_of(n, MemNode::Address, addp);
 175       ideal_nodes.push(addp);
 176       _nodes.at_put_grow(addp->_idx, nullptr, nullptr);
 177     }
 178     // Create PointsTo nodes and add them to Connection Graph. Called
 179     // only once per ideal node since ideal_nodes is Unique_Node list.
 180     add_node_to_connection_graph(n, &delayed_worklist);
 181     PointsToNode* ptn = ptnode_adr(n->_idx);
 182     if (ptn != nullptr && ptn != phantom_obj) {
 183       ptnodes_worklist.append(ptn);
 184       if (ptn->is_JavaObject()) {
 185         java_objects_worklist.append(ptn->as_JavaObject());
 186         if ((n->is_Allocate() || n->is_CallStaticJava()) &&
 187             (ptn->escape_state() < PointsToNode::GlobalEscape)) {
 188           // Only allocations and java static calls results are interesting.
 189           non_escaped_allocs_worklist.append(ptn->as_JavaObject());
 190         }
 191       } else if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
 192         oop_fields_worklist.append(ptn->as_Field());
 193       }
 194     }
 195     // Collect some interesting nodes for further use.
 196     switch (n->Opcode()) {
 197       case Op_MergeMem:
 198         // Collect all MergeMem nodes to add memory slices for
 199         // scalar replaceable objects in split_unique_types().
 200         mergemem_worklist.append(n->as_MergeMem());
 201         break;
 202       case Op_CmpP:
 203       case Op_CmpN:
 204         // Collect compare pointers nodes.
 205         if (OptimizePtrCompare) {
 206           ptr_cmp_worklist.append(n);
 207         }
 208         break;
 209       case Op_MemBarStoreStore:
 210         // Collect all MemBarStoreStore nodes so that depending on the
 211         // escape status of the associated Allocate node some of them
 212         // may be eliminated.
 213         if (!UseStoreStoreForCtor || n->req() > MemBarNode::Precedent) {
 214           storestore_worklist.append(n->as_MemBarStoreStore());
 215         }
 216         break;
 217       case Op_MemBarRelease:
 218         if (n->req() > MemBarNode::Precedent) {
 219           record_for_optimizer(n);
 220         }
 221         break;
 222 #ifdef ASSERT
 223       case Op_AddP:
 224         // Collect address nodes for graph verification.
 225         addp_worklist.append(n);
 226         break;
 227 #endif
 228       case Op_ArrayCopy:
 229         // Keep a list of ArrayCopy nodes so if one of its input is non
 230         // escaping, we can record a unique type
 231         arraycopy_worklist.append(n->as_ArrayCopy());
 232         break;
 233       default:
 234         // not interested now, ignore...
 235         break;
 236     }
 237     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 238       Node* m = n->fast_out(i);   // Get user
 239       ideal_nodes.push(m);
 240     }
 241     if (n->is_SafePoint()) {
 242       sfn_worklist.append(n->as_SafePoint());
 243     }
 244   }
 245 
 246 #ifndef PRODUCT
 247   if (_compile->directive()->TraceEscapeAnalysisOption) {
 248     tty->print("+++++ Initial worklist for ");
 249     _compile->method()->print_name();
 250     tty->print_cr(" (ea_inv=%d)", _invocation);
 251     for (int i = 0; i < ptnodes_worklist.length(); i++) {
 252       PointsToNode* ptn = ptnodes_worklist.at(i);
 253       ptn->dump();
 254     }
 255     tty->print_cr("+++++ Calculating escape states and scalar replaceability");
 256   }
 257 #endif
 258 
 259   if (non_escaped_allocs_worklist.length() == 0) {
 260     _collecting = false;
 261     NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 262     return false; // Nothing to do.
 263   }
 264   // Add final simple edges to graph.
 265   while(delayed_worklist.size() > 0) {
 266     Node* n = delayed_worklist.pop();
 267     add_final_edges(n);
 268   }
 269 
 270 #ifdef ASSERT
 271   if (VerifyConnectionGraph) {
 272     // Verify that no new simple edges could be created and all
 273     // local vars has edges.
 274     _verify = true;
 275     int ptnodes_length = ptnodes_worklist.length();
 276     for (int next = 0; next < ptnodes_length; ++next) {
 277       PointsToNode* ptn = ptnodes_worklist.at(next);
 278       add_final_edges(ptn->ideal_node());
 279       if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
 280         ptn->dump();
 281         assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
 282       }
 283     }
 284     _verify = false;
 285   }
 286 #endif
 287   // Bytecode analyzer BCEscapeAnalyzer, used for Call nodes
 288   // processing, calls to CI to resolve symbols (types, fields, methods)
 289   // referenced in bytecode. During symbol resolution VM may throw
 290   // an exception which CI cleans and converts to compilation failure.
 291   if (C->failing()) {
 292     NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 293     return false;
 294   }
 295 
 296   // 2. Finish Graph construction by propagating references to all
 297   //    java objects through graph.
 298   if (!complete_connection_graph(ptnodes_worklist, non_escaped_allocs_worklist,
 299                                  java_objects_worklist, oop_fields_worklist)) {
 300     // All objects escaped or hit time or iterations limits.
 301     _collecting = false;
 302     NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 303     return false;
 304   }
 305 
 306   // 3. Adjust scalar_replaceable state of nonescaping objects and push
 307   //    scalar replaceable allocations on alloc_worklist for processing
 308   //    in split_unique_types().
 309   GrowableArray<JavaObjectNode*> jobj_worklist;
 310   int non_escaped_length = non_escaped_allocs_worklist.length();
 311   bool found_nsr_alloc = false;
 312   for (int next = 0; next < non_escaped_length; next++) {
 313     JavaObjectNode* ptn = non_escaped_allocs_worklist.at(next);
 314     bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
 315     Node* n = ptn->ideal_node();
 316     if (n->is_Allocate()) {
 317       n->as_Allocate()->_is_non_escaping = noescape;
 318     }
 319     if (noescape && ptn->scalar_replaceable()) {
 320       adjust_scalar_replaceable_state(ptn, reducible_merges);
 321       if (ptn->scalar_replaceable()) {
 322         jobj_worklist.push(ptn);
 323       } else {
 324         found_nsr_alloc = true;
 325       }
 326     }
 327   }
 328 
 329   // Propagate NSR (Not Scalar Replaceable) state.
 330   if (found_nsr_alloc) {
 331     find_scalar_replaceable_allocs(jobj_worklist, reducible_merges);
 332   }
 333 
 334   // alloc_worklist will be processed in reverse push order.
 335   // Therefore the reducible Phis will be processed for last and that's what we
 336   // want because by then the scalarizable inputs of the merge will already have
 337   // an unique instance type.
 338   for (uint i = 0; i < reducible_merges.size(); i++ ) {
 339     Node* n = reducible_merges.at(i);
 340     alloc_worklist.append(n);
 341   }
 342 
 343   for (int next = 0; next < jobj_worklist.length(); ++next) {
 344     JavaObjectNode* jobj = jobj_worklist.at(next);
 345     if (jobj->scalar_replaceable()) {
 346       alloc_worklist.append(jobj->ideal_node());
 347     }
 348   }
 349 
 350 #ifdef ASSERT
 351   if (VerifyConnectionGraph) {
 352     // Verify that graph is complete - no new edges could be added or needed.
 353     verify_connection_graph(ptnodes_worklist, non_escaped_allocs_worklist,
 354                             java_objects_worklist, addp_worklist);
 355   }
 356   assert(C->unique() == nodes_size(), "no new ideal nodes should be added during ConnectionGraph build");
 357   assert(null_obj->escape_state() == PointsToNode::NoEscape &&
 358          null_obj->edge_count() == 0 &&
 359          !null_obj->arraycopy_src() &&
 360          !null_obj->arraycopy_dst(), "sanity");
 361 #endif
 362 
 363   _collecting = false;
 364 
 365   } // TracePhase t3("connectionGraph")
 366 
 367   // 4. Optimize ideal graph based on EA information.
 368   bool has_non_escaping_obj = (non_escaped_allocs_worklist.length() > 0);
 369   if (has_non_escaping_obj) {
 370     optimize_ideal_graph(ptr_cmp_worklist, storestore_worklist);
 371   }
 372 
 373 #ifndef PRODUCT
 374   if (PrintEscapeAnalysis) {
 375     dump(ptnodes_worklist); // Dump ConnectionGraph
 376   }
 377 #endif
 378 
 379 #ifdef ASSERT
 380   if (VerifyConnectionGraph) {
 381     int alloc_length = alloc_worklist.length();
 382     for (int next = 0; next < alloc_length; ++next) {
 383       Node* n = alloc_worklist.at(next);
 384       PointsToNode* ptn = ptnode_adr(n->_idx);
 385       assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
 386     }
 387   }
 388 
 389   if (VerifyReduceAllocationMerges) {
 390     for (uint i = 0; i < reducible_merges.size(); i++ ) {
 391       Node* n = reducible_merges.at(i);
 392       if (!can_reduce_phi(n->as_Phi())) {
 393         TraceReduceAllocationMerges = true;
 394         n->dump(2);
 395         n->dump(-2);
 396         assert(can_reduce_phi(n->as_Phi()), "Sanity: previous reducible Phi is no longer reducible before SUT.");
 397       }
 398     }
 399   }
 400 #endif
 401 
 402   // 5. Separate memory graph for scalar replaceable allcations.
 403   bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
 404   if (has_scalar_replaceable_candidates && EliminateAllocations) {
 405     assert(C->do_aliasing(), "Aliasing should be enabled");
 406     // Now use the escape information to create unique types for
 407     // scalar replaceable objects.
 408     split_unique_types(alloc_worklist, arraycopy_worklist, mergemem_worklist, reducible_merges);
 409     if (C->failing()) {
 410       NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 411       return false;
 412     }
 413     C->print_method(PHASE_AFTER_EA, 2);
 414 
 415 #ifdef ASSERT
 416   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
 417     tty->print("=== No allocations eliminated for ");
 418     C->method()->print_short_name();
 419     if (!EliminateAllocations) {
 420       tty->print(" since EliminateAllocations is off ===");
 421     } else if(!has_scalar_replaceable_candidates) {
 422       tty->print(" since there are no scalar replaceable candidates ===");
 423     }
 424     tty->cr();
 425 #endif
 426   }
 427 
 428   // 6. Reduce allocation merges used as debug information. This is done after
 429   // split_unique_types because the methods used to create SafePointScalarObject
 430   // need to traverse the memory graph to find values for object fields. We also
 431   // set to null the scalarized inputs of reducible Phis so that the Allocate
 432   // that they point can be later scalar replaced.
 433   bool delay = _igvn->delay_transform();
 434   _igvn->set_delay_transform(true);
 435   for (uint i = 0; i < reducible_merges.size(); i++) {
 436     Node* n = reducible_merges.at(i);
 437     if (n->outcnt() > 0) {
 438       if (!reduce_phi_on_safepoints(n->as_Phi())) {
 439         NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 440         C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
 441         return false;
 442       }
 443 
 444       // Now we set the scalar replaceable inputs of ophi to null, which is
 445       // the last piece that would prevent it from being scalar replaceable.
 446       reset_scalar_replaceable_entries(n->as_Phi());
 447     }
 448   }
 449   _igvn->set_delay_transform(delay);
 450 
 451   // Annotate at safepoints if they have <= ArgEscape objects in their scope and at
 452   // java calls if they pass ArgEscape objects as parameters.
 453   if (has_non_escaping_obj &&
 454       (C->env()->should_retain_local_variables() ||
 455        C->env()->jvmti_can_get_owned_monitor_info() ||
 456        C->env()->jvmti_can_walk_any_space() ||
 457        DeoptimizeObjectsALot)) {
 458     int sfn_length = sfn_worklist.length();
 459     for (int next = 0; next < sfn_length; next++) {
 460       SafePointNode* sfn = sfn_worklist.at(next);
 461       sfn->set_has_ea_local_in_scope(has_ea_local_in_scope(sfn));
 462       if (sfn->is_CallJava()) {
 463         CallJavaNode* call = sfn->as_CallJava();
 464         call->set_arg_escape(has_arg_escape(call));
 465       }
 466     }
 467   }
 468 
 469   NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 470   return has_non_escaping_obj;
 471 }
 472 
 473 // Check if it's profitable to reduce the Phi passed as parameter.  Returns true
 474 // if at least one scalar replaceable allocation participates in the merge.
 475 bool ConnectionGraph::can_reduce_phi_check_inputs(PhiNode* ophi) const {
 476   bool found_sr_allocate = false;
 477 
 478   for (uint i = 1; i < ophi->req(); i++) {
 479     JavaObjectNode* ptn = unique_java_object(ophi->in(i));
 480     if (ptn != nullptr && ptn->scalar_replaceable()) {
 481       AllocateNode* alloc = ptn->ideal_node()->as_Allocate();
 482 
 483       // Don't handle arrays.
 484       if (alloc->Opcode() != Op_Allocate) {
 485         assert(alloc->Opcode() == Op_AllocateArray, "Unexpected type of allocation.");
 486         continue;
 487       }
 488 
 489       if (PhaseMacroExpand::can_eliminate_allocation(_igvn, alloc, nullptr)) {
 490         found_sr_allocate = true;
 491       } else {
 492         NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("%dth input of Phi %d is SR but can't be eliminated.", i, ophi->_idx);)
 493         ptn->set_scalar_replaceable(false);
 494       }
 495     }
 496   }
 497 
 498   NOT_PRODUCT(if (TraceReduceAllocationMerges && !found_sr_allocate) tty->print_cr("Can NOT reduce Phi %d on invocation %d. No SR Allocate as input.", ophi->_idx, _invocation);)
 499   return found_sr_allocate;
 500 }
 501 
 502 // We can reduce the Cmp if it's a comparison between the Phi and a constant.
 503 // I require the 'other' input to be a constant so that I can move the Cmp
 504 // around safely.
 505 bool ConnectionGraph::can_reduce_cmp(Node* n, Node* cmp) const {
 506   assert(cmp->Opcode() == Op_CmpP || cmp->Opcode() == Op_CmpN, "not expected node: %s", cmp->Name());
 507   Node* left = cmp->in(1);
 508   Node* right = cmp->in(2);
 509 
 510   return (left == n || right == n) &&
 511          (left->is_Con() || right->is_Con()) &&
 512          cmp->outcnt() == 1;
 513 }
 514 
 515 // We are going to check if any of the SafePointScalarMerge entries
 516 // in the SafePoint reference the Phi that we are checking.
 517 bool ConnectionGraph::has_been_reduced(PhiNode* n, SafePointNode* sfpt) const {
 518   JVMState *jvms = sfpt->jvms();
 519 
 520   for (uint i = jvms->debug_start(); i < jvms->debug_end(); i++) {
 521     Node* sfpt_in = sfpt->in(i);
 522     if (sfpt_in->is_SafePointScalarMerge()) {
 523       SafePointScalarMergeNode* smerge = sfpt_in->as_SafePointScalarMerge();
 524       Node* nsr_ptr = sfpt->in(smerge->merge_pointer_idx(jvms));
 525       if (nsr_ptr == n) {
 526         return true;
 527       }
 528     }
 529   }
 530 
 531   return false;
 532 }
 533 
 534 // Check if we are able to untangle the merge. The following patterns are
 535 // supported:
 536 //  - Phi -> SafePoints
 537 //  - Phi -> CmpP/N
 538 //  - Phi -> AddP -> Load
 539 //  - Phi -> CastPP -> SafePoints
 540 //  - Phi -> CastPP -> AddP -> Load
 541 bool ConnectionGraph::can_reduce_check_users(Node* n, uint nesting) const {
 542   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 543     Node* use = n->fast_out(i);
 544 
 545     if (use->is_SafePoint()) {
 546       if (use->is_Call() && use->as_Call()->has_non_debug_use(n)) {
 547         NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. Call has non_debug_use().", n->_idx, _invocation);)
 548         return false;
 549       } else if (has_been_reduced(n->is_Phi() ? n->as_Phi() : n->as_CastPP()->in(1)->as_Phi(), use->as_SafePoint())) {
 550         NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. It has already been reduced.", n->_idx, _invocation);)
 551         return false;
 552       }
 553     } else if (use->is_AddP()) {
 554       Node* addp = use;
 555       for (DUIterator_Fast jmax, j = addp->fast_outs(jmax); j < jmax; j++) {
 556         Node* use_use = addp->fast_out(j);
 557         const Type* load_type = _igvn->type(use_use);
 558 
 559         if (!use_use->is_Load() || !use_use->as_Load()->can_split_through_phi_base(_igvn)) {
 560           NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. AddP user isn't a [splittable] Load(): %s", n->_idx, _invocation, use_use->Name());)
 561           return false;
 562         } else if (load_type->isa_narrowklass() || load_type->isa_klassptr()) {
 563           NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. [Narrow] Klass Load: %s", n->_idx, _invocation, use_use->Name());)
 564           return false;
 565         }
 566       }
 567     } else if (nesting > 0) {
 568       NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. Unsupported user %s at nesting level %d.", n->_idx, _invocation, use->Name(), nesting);)
 569       return false;
 570     } else if (use->is_CastPP()) {
 571       const Type* cast_t = _igvn->type(use);
 572       if (cast_t == nullptr || cast_t->make_ptr()->isa_instptr() == nullptr) {
 573 #ifndef PRODUCT
 574         if (TraceReduceAllocationMerges) {
 575           tty->print_cr("Can NOT reduce Phi %d on invocation %d. CastPP is not to an instance.", n->_idx, _invocation);
 576           use->dump();
 577         }
 578 #endif
 579         return false;
 580       }
 581 
 582       bool is_trivial_control = use->in(0) == nullptr || use->in(0) == n->in(0);
 583       if (!is_trivial_control) {
 584         // If it's not a trivial control then we check if we can reduce the
 585         // CmpP/N used by the If controlling the cast.
 586         if (use->in(0)->is_IfTrue() || use->in(0)->is_IfFalse()) {
 587           Node* iff = use->in(0)->in(0);
 588           // We may have an OpaqueNotNull node between If and Bool nodes. But we could also have a sub class of IfNode,
 589           // for example, an OuterStripMinedLoopEnd or a Parse Predicate. Bail out in all these cases.
 590           bool can_reduce = (iff->Opcode() == Op_If) && iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp();
 591           if (can_reduce) {
 592             Node* iff_cmp = iff->in(1)->in(1);
 593             int opc = iff_cmp->Opcode();
 594             can_reduce = (opc == Op_CmpP || opc == Op_CmpN) && can_reduce_cmp(n, iff_cmp);
 595           }
 596           if (!can_reduce) {
 597 #ifndef PRODUCT
 598             if (TraceReduceAllocationMerges) {
 599               tty->print_cr("Can NOT reduce Phi %d on invocation %d. CastPP %d doesn't have simple control.", n->_idx, _invocation, use->_idx);
 600               n->dump(5);
 601             }
 602 #endif
 603             return false;
 604           }
 605         }
 606       }
 607 
 608       if (!can_reduce_check_users(use, nesting+1)) {
 609         return false;
 610       }
 611     } else if (use->Opcode() == Op_CmpP || use->Opcode() == Op_CmpN) {
 612       if (!can_reduce_cmp(n, use)) {
 613         NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. CmpP/N %d isn't reducible.", n->_idx, _invocation, use->_idx);)
 614         return false;
 615       }
 616     } else {
 617       NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. One of the uses is: %d %s", n->_idx, _invocation, use->_idx, use->Name());)
 618       return false;
 619     }
 620   }
 621 
 622   return true;
 623 }
 624 
 625 // Returns true if: 1) It's profitable to reduce the merge, and 2) The Phi is
 626 // only used in some certain code shapes. Check comments in
 627 // 'can_reduce_phi_inputs' and 'can_reduce_phi_users' for more
 628 // details.
 629 bool ConnectionGraph::can_reduce_phi(PhiNode* ophi) const {
 630   // If there was an error attempting to reduce allocation merges for this
 631   // method we might have disabled the compilation and be retrying with RAM
 632   // disabled.
 633   if (!_compile->do_reduce_allocation_merges() || ophi->region()->Opcode() != Op_Region) {
 634     return false;
 635   }
 636 
 637   const Type* phi_t = _igvn->type(ophi);
 638   if (phi_t == nullptr ||
 639       phi_t->make_ptr() == nullptr ||
 640       phi_t->make_ptr()->isa_aryptr() != nullptr) {
 641     return false;
 642   }
 643 
 644   if (!can_reduce_phi_check_inputs(ophi) || !can_reduce_check_users(ophi, /* nesting: */ 0)) {
 645     return false;
 646   }
 647 
 648   NOT_PRODUCT(if (TraceReduceAllocationMerges) { tty->print_cr("Can reduce Phi %d during invocation %d: ", ophi->_idx, _invocation); })
 649   return true;
 650 }
 651 
 652 // This method will return a CmpP/N that we need to use on the If controlling a
 653 // CastPP after it was split. This method is only called on bases that are
 654 // nullable therefore we always need a controlling if for the splitted CastPP.
 655 //
 656 // 'curr_ctrl' is the control of the CastPP that we want to split through phi.
 657 // If the CastPP currently doesn't have a control then the CmpP/N will be
 658 // against the null constant, otherwise it will be against the constant input of
 659 // the existing CmpP/N. It's guaranteed that there will be a CmpP/N in the later
 660 // case because we have constraints on it and because the CastPP has a control
 661 // input.
 662 Node* ConnectionGraph::specialize_cmp(Node* base, Node* curr_ctrl) {
 663   const Type* t = base->bottom_type();
 664   Node* con = nullptr;
 665 
 666   if (curr_ctrl == nullptr || curr_ctrl->is_Region()) {
 667     con = _igvn->zerocon(t->basic_type());
 668   } else {
 669     // can_reduce_check_users() verified graph: true/false -> if -> bool -> cmp
 670     assert(curr_ctrl->in(0)->Opcode() == Op_If, "unexpected node %s", curr_ctrl->in(0)->Name());
 671     Node* bol = curr_ctrl->in(0)->in(1);
 672     assert(bol->is_Bool(), "unexpected node %s", bol->Name());
 673     Node* curr_cmp = bol->in(1);
 674     assert(curr_cmp->Opcode() == Op_CmpP || curr_cmp->Opcode() == Op_CmpN, "unexpected node %s", curr_cmp->Name());
 675     con = curr_cmp->in(1)->is_Con() ? curr_cmp->in(1) : curr_cmp->in(2);
 676   }
 677 
 678   return CmpNode::make(base, con, t->basic_type());
 679 }
 680 
 681 // This method 'specializes' the CastPP passed as parameter to the base passed
 682 // as parameter. Note that the existing CastPP input is a Phi. "Specialize"
 683 // means that the CastPP now will be specific for a given base instead of a Phi.
 684 // An If-Then-Else-Region block is inserted to control the CastPP. The control
 685 // of the CastPP is a copy of the current one (if there is one) or a check
 686 // against null.
 687 //
 688 // Before:
 689 //
 690 //    C1     C2  ... Cn
 691 //     \      |      /
 692 //      \     |     /
 693 //       \    |    /
 694 //        \   |   /
 695 //         \  |  /
 696 //          \ | /
 697 //           \|/
 698 //          Region     B1      B2  ... Bn
 699 //            |          \      |      /
 700 //            |           \     |     /
 701 //            |            \    |    /
 702 //            |             \   |   /
 703 //            |              \  |  /
 704 //            |               \ | /
 705 //            ---------------> Phi
 706 //                              |
 707 //                      X       |
 708 //                      |       |
 709 //                      |       |
 710 //                      ------> CastPP
 711 //
 712 // After (only partial illustration; base = B2, current_control = C2):
 713 //
 714 //                      C2
 715 //                      |
 716 //                      If
 717 //                     / \
 718 //                    /   \
 719 //                   T     F
 720 //                  /\     /
 721 //                 /  \   /
 722 //                /    \ /
 723 //      C1    CastPP   Reg        Cn
 724 //       |              |          |
 725 //       |              |          |
 726 //       |              |          |
 727 //       -------------- | ----------
 728 //                    | | |
 729 //                    Region
 730 //
 731 Node* ConnectionGraph::specialize_castpp(Node* castpp, Node* base, Node* current_control) {
 732   Node* control_successor  = current_control->unique_ctrl_out();
 733   Node* cmp                = _igvn->transform(specialize_cmp(base, castpp->in(0)));
 734   Node* bol                = _igvn->transform(new BoolNode(cmp, BoolTest::ne));
 735   IfNode* if_ne            = _igvn->transform(new IfNode(current_control, bol, PROB_MIN, COUNT_UNKNOWN))->as_If();
 736   Node* not_eq_control     = _igvn->transform(new IfTrueNode(if_ne));
 737   Node* yes_eq_control     = _igvn->transform(new IfFalseNode(if_ne));
 738   Node* end_region         = _igvn->transform(new RegionNode(3));
 739 
 740   // Insert the new if-else-region block into the graph
 741   end_region->set_req(1, not_eq_control);
 742   end_region->set_req(2, yes_eq_control);
 743   control_successor->replace_edge(current_control, end_region, _igvn);
 744 
 745   _igvn->_worklist.push(current_control);
 746   _igvn->_worklist.push(control_successor);
 747 
 748   return _igvn->transform(ConstraintCastNode::make_cast_for_type(not_eq_control, base, _igvn->type(castpp), ConstraintCastNode::UnconditionalDependency, nullptr));
 749 }
 750 
 751 Node* ConnectionGraph::split_castpp_load_through_phi(Node* curr_addp, Node* curr_load, Node* region, GrowableArray<Node*>* bases_for_loads, GrowableArray<Node *>  &alloc_worklist) {
 752   const Type* load_type = _igvn->type(curr_load);
 753   Node* nsr_value = _igvn->zerocon(load_type->basic_type());
 754   Node* memory = curr_load->in(MemNode::Memory);
 755 
 756   // The data_phi merging the loads needs to be nullable if
 757   // we are loading pointers.
 758   if (load_type->make_ptr() != nullptr) {
 759     if (load_type->isa_narrowoop()) {
 760       load_type = load_type->meet(TypeNarrowOop::NULL_PTR);
 761     } else if (load_type->isa_ptr()) {
 762       load_type = load_type->meet(TypePtr::NULL_PTR);
 763     } else {
 764       assert(false, "Unexpected load ptr type.");
 765     }
 766   }
 767 
 768   Node* data_phi = PhiNode::make(region, nsr_value, load_type);
 769 
 770   for (int i = 1; i < bases_for_loads->length(); i++) {
 771     Node* base = bases_for_loads->at(i);
 772     Node* cmp_region = nullptr;
 773     if (base != nullptr) {
 774       if (base->is_CFG()) { // means that we added a CastPP as child of this CFG node
 775         cmp_region = base->unique_ctrl_out_or_null();
 776         assert(cmp_region != nullptr, "There should be.");
 777         base = base->find_out_with(Op_CastPP);
 778       }
 779 
 780       Node* addr = _igvn->transform(new AddPNode(base, base, curr_addp->in(AddPNode::Offset)));
 781       Node* mem = (memory->is_Phi() && (memory->in(0) == region)) ? memory->in(i) : memory;
 782       Node* load = curr_load->clone();
 783       load->set_req(0, nullptr);
 784       load->set_req(1, mem);
 785       load->set_req(2, addr);
 786 
 787       if (cmp_region != nullptr) { // see comment on previous if
 788         Node* intermediate_phi = PhiNode::make(cmp_region, nsr_value, load_type);
 789         intermediate_phi->set_req(1, _igvn->transform(load));
 790         load = intermediate_phi;
 791       }
 792 
 793       data_phi->set_req(i, _igvn->transform(load));
 794     } else {
 795       // Just use the default, which is already in phi
 796     }
 797   }
 798 
 799   // Takes care of updating CG and split_unique_types worklists due
 800   // to cloned AddP->Load.
 801   updates_after_load_split(data_phi, curr_load, alloc_worklist);
 802 
 803   return _igvn->transform(data_phi);
 804 }
 805 
 806 // This method only reduces CastPP fields loads; SafePoints are handled
 807 // separately. The idea here is basically to clone the CastPP and place copies
 808 // on each input of the Phi, including non-scalar replaceable inputs.
 809 // Experimentation shows that the resulting IR graph is simpler that way than if
 810 // we just split the cast through scalar-replaceable inputs.
 811 //
 812 // The reduction process requires that CastPP's control be one of:
 813 //  1) no control,
 814 //  2) the same region as Ophi, or
 815 //  3) an IfTrue/IfFalse coming from an CmpP/N between Ophi and a constant.
 816 //
 817 // After splitting the CastPP we'll put it under an If-Then-Else-Region control
 818 // flow. If the CastPP originally had an IfTrue/False control input then we'll
 819 // use a similar CmpP/N to control the new If-Then-Else-Region. Otherwise, we'll
 820 // juse use a CmpP/N against the null constant.
 821 //
 822 // The If-Then-Else-Region isn't always needed. For instance, if input to
 823 // splitted cast was not nullable (or if it was the null constant) then we don't
 824 // need (shouldn't) use a CastPP at all.
 825 //
 826 // After the casts are splitted we'll split the AddP->Loads through the Phi and
 827 // connect them to the just split CastPPs.
 828 //
 829 // Before (CastPP control is same as Phi):
 830 //
 831 //          Region     Allocate   Null    Call
 832 //            |             \      |      /
 833 //            |              \     |     /
 834 //            |               \    |    /
 835 //            |                \   |   /
 836 //            |                 \  |  /
 837 //            |                  \ | /
 838 //            ------------------> Phi            # Oop Phi
 839 //            |                    |
 840 //            |                    |
 841 //            |                    |
 842 //            |                    |
 843 //            ----------------> CastPP
 844 //                                 |
 845 //                               AddP
 846 //                                 |
 847 //                               Load
 848 //
 849 // After (Very much simplified):
 850 //
 851 //                         Call  Null
 852 //                            \  /
 853 //                            CmpP
 854 //                             |
 855 //                           Bool#NE
 856 //                             |
 857 //                             If
 858 //                            / \
 859 //                           T   F
 860 //                          / \ /
 861 //                         /   R
 862 //                     CastPP  |
 863 //                       |     |
 864 //                     AddP    |
 865 //                       |     |
 866 //                     Load    |
 867 //                         \   |   0
 868 //            Allocate      \  |  /
 869 //                \          \ | /
 870 //               AddP         Phi
 871 //                  \         /
 872 //                 Load      /
 873 //                    \  0  /
 874 //                     \ | /
 875 //                      \|/
 876 //                      Phi        # "Field" Phi
 877 //
 878 void ConnectionGraph::reduce_phi_on_castpp_field_load(Node* curr_castpp, GrowableArray<Node *>  &alloc_worklist, GrowableArray<Node *>  &memnode_worklist) {
 879   Node* ophi = curr_castpp->in(1);
 880   assert(ophi->is_Phi(), "Expected this to be a Phi node.");
 881 
 882   // Identify which base should be used for AddP->Load later when spliting the
 883   // CastPP->Loads through ophi. Three kind of values may be stored in this
 884   // array, depending on the nullability status of the corresponding input in
 885   // ophi.
 886   //
 887   //  - nullptr:    Meaning that the base is actually the null constant and therefore
 888   //                we won't try to load from it.
 889   //
 890   //  - CFG Node:   Meaning that the base is a CastPP that was specialized for
 891   //                this input of Ophi. I.e., we added an If->Then->Else-Region
 892   //                that will 'activate' the CastPp only when the input is not Null.
 893   //
 894   //  - Other Node: Meaning that the base is not nullable and therefore we'll try
 895   //                to load directly from it.
 896   GrowableArray<Node*> bases_for_loads(ophi->req(), ophi->req(), nullptr);
 897 
 898   for (uint i = 1; i < ophi->req(); i++) {
 899     Node* base = ophi->in(i);
 900     const Type* base_t = _igvn->type(base);
 901 
 902     if (base_t->maybe_null()) {
 903       if (base->is_Con()) {
 904         // Nothing todo as bases_for_loads[i] is already null
 905       } else {
 906         Node* new_castpp = specialize_castpp(curr_castpp, base, ophi->in(0)->in(i));
 907         bases_for_loads.at_put(i, new_castpp->in(0)); // Use the ctrl of the new node just as a flag
 908       }
 909     } else {
 910       bases_for_loads.at_put(i, base);
 911     }
 912   }
 913 
 914   // Now let's split the CastPP->Loads through the Phi
 915   for (int i = curr_castpp->outcnt()-1; i >= 0;) {
 916     Node* use = curr_castpp->raw_out(i);
 917     if (use->is_AddP()) {
 918       for (int j = use->outcnt()-1; j >= 0;) {
 919         Node* use_use = use->raw_out(j);
 920         assert(use_use->is_Load(), "Expected this to be a Load node.");
 921 
 922         // We can't make an unconditional load from a nullable input. The
 923         // 'split_castpp_load_through_phi` method will add an
 924         // 'If-Then-Else-Region` around nullable bases and only load from them
 925         // when the input is not null.
 926         Node* phi = split_castpp_load_through_phi(use, use_use, ophi->in(0), &bases_for_loads, alloc_worklist);
 927         _igvn->replace_node(use_use, phi);
 928 
 929         --j;
 930         j = MIN2(j, (int)use->outcnt()-1);
 931       }
 932 
 933       _igvn->remove_dead_node(use);
 934     }
 935     --i;
 936     i = MIN2(i, (int)curr_castpp->outcnt()-1);
 937   }
 938 }
 939 
 940 // This method split a given CmpP/N through the Phi used in one of its inputs.
 941 // As a result we convert a comparison with a pointer to a comparison with an
 942 // integer.
 943 // The only requirement is that one of the inputs of the CmpP/N must be a Phi
 944 // while the other must be a constant.
 945 // The splitting process is basically just cloning the CmpP/N above the input
 946 // Phi.  However, some (most) of the cloned CmpP/Ns won't be requred because we
 947 // can prove at compile time the result of the comparison.
 948 //
 949 // Before:
 950 //
 951 //             in1    in2 ... inN
 952 //              \      |      /
 953 //               \     |     /
 954 //                \    |    /
 955 //                 \   |   /
 956 //                  \  |  /
 957 //                   \ | /
 958 //                    Phi
 959 //                     |   Other
 960 //                     |    /
 961 //                     |   /
 962 //                     |  /
 963 //                    CmpP/N
 964 //
 965 // After:
 966 //
 967 //        in1  Other   in2 Other  inN  Other
 968 //         |    |      |   |      |    |
 969 //         \    |      |   |      |    |
 970 //          \  /       |   /      |    /
 971 //          CmpP/N    CmpP/N     CmpP/N
 972 //          Bool      Bool       Bool
 973 //            \        |        /
 974 //             \       |       /
 975 //              \      |      /
 976 //               \     |     /
 977 //                \    |    /
 978 //                 \   |   /
 979 //                  \  |  /
 980 //                   \ | /
 981 //                    Phi
 982 //                     |
 983 //                     |   Zero
 984 //                     |    /
 985 //                     |   /
 986 //                     |  /
 987 //                     CmpI
 988 //
 989 //
 990 void ConnectionGraph::reduce_phi_on_cmp(Node* cmp) {
 991   Node* ophi = cmp->in(1)->is_Con() ? cmp->in(2) : cmp->in(1);
 992   assert(ophi->is_Phi(), "Expected this to be a Phi node.");
 993 
 994   Node* other = cmp->in(1)->is_Con() ? cmp->in(1) : cmp->in(2);
 995   Node* zero = _igvn->intcon(0);
 996   Node* one = _igvn->intcon(1);
 997   BoolTest::mask mask = cmp->unique_out()->as_Bool()->_test._test;
 998 
 999   // This Phi will merge the result of the Cmps split through the Phi
1000   Node* res_phi = PhiNode::make(ophi->in(0), zero, TypeInt::INT);
1001 
1002   for (uint i=1; i<ophi->req(); i++) {
1003     Node* ophi_input = ophi->in(i);
1004     Node* res_phi_input = nullptr;
1005 
1006     const TypeInt* tcmp = optimize_ptr_compare(ophi_input, other);
1007     if (tcmp->singleton()) {
1008       if ((mask == BoolTest::mask::eq && tcmp == TypeInt::CC_EQ) ||
1009           (mask == BoolTest::mask::ne && tcmp == TypeInt::CC_GT)) {
1010         res_phi_input = one;
1011       } else {
1012         res_phi_input = zero;
1013       }
1014     } else {
1015       Node* ncmp = _igvn->transform(cmp->clone());
1016       ncmp->set_req(1, ophi_input);
1017       ncmp->set_req(2, other);
1018       Node* bol = _igvn->transform(new BoolNode(ncmp, mask));
1019       res_phi_input = bol->as_Bool()->as_int_value(_igvn);
1020     }
1021 
1022     res_phi->set_req(i, res_phi_input);
1023   }
1024 
1025   // This CMP always compares whether the output of "res_phi" is TRUE as far as the "mask".
1026   Node* new_cmp = _igvn->transform(new CmpINode(_igvn->transform(res_phi), (mask == BoolTest::mask::eq) ? one : zero));
1027   _igvn->replace_node(cmp, new_cmp);
1028 }
1029 
1030 // Push the newly created AddP on alloc_worklist and patch
1031 // the connection graph. Note that the changes in the CG below
1032 // won't affect the ES of objects since the new nodes have the
1033 // same status as the old ones.
1034 void ConnectionGraph::updates_after_load_split(Node* data_phi, Node* previous_load, GrowableArray<Node *>  &alloc_worklist) {
1035   assert(data_phi != nullptr, "Output of split_through_phi is null.");
1036   assert(data_phi != previous_load, "Output of split_through_phi is same as input.");
1037   assert(data_phi->is_Phi(), "Output of split_through_phi isn't a Phi.");
1038 
1039   if (data_phi == nullptr || !data_phi->is_Phi()) {
1040     // Make this a retry?
1041     return ;
1042   }
1043 
1044   Node* previous_addp = previous_load->in(MemNode::Address);
1045   FieldNode* fn = ptnode_adr(previous_addp->_idx)->as_Field();
1046   for (uint i = 1; i < data_phi->req(); i++) {
1047     Node* new_load = data_phi->in(i);
1048 
1049     if (new_load->is_Phi()) {
1050       // new_load is currently the "intermediate_phi" from an specialized
1051       // CastPP.
1052       new_load = new_load->in(1);
1053     }
1054 
1055     // "new_load" might actually be a constant, parameter, etc.
1056     if (new_load->is_Load()) {
1057       Node* new_addp = new_load->in(MemNode::Address);
1058       Node* base = get_addp_base(new_addp);
1059 
1060       // The base might not be something that we can create an unique
1061       // type for. If that's the case we are done with that input.
1062       PointsToNode* jobj_ptn = unique_java_object(base);
1063       if (jobj_ptn == nullptr || !jobj_ptn->scalar_replaceable()) {
1064         continue;
1065       }
1066 
1067       // Push to alloc_worklist since the base has an unique_type
1068       alloc_worklist.append_if_missing(new_addp);
1069 
1070       // Now let's add the node to the connection graph
1071       _nodes.at_grow(new_addp->_idx, nullptr);
1072       add_field(new_addp, fn->escape_state(), fn->offset());
1073       add_base(ptnode_adr(new_addp->_idx)->as_Field(), ptnode_adr(base->_idx));
1074 
1075       // If the load doesn't load an object then it won't be
1076       // part of the connection graph
1077       PointsToNode* curr_load_ptn = ptnode_adr(previous_load->_idx);
1078       if (curr_load_ptn != nullptr) {
1079         _nodes.at_grow(new_load->_idx, nullptr);
1080         add_local_var(new_load, curr_load_ptn->escape_state());
1081         add_edge(ptnode_adr(new_load->_idx), ptnode_adr(new_addp->_idx)->as_Field());
1082       }
1083     }
1084   }
1085 }
1086 
1087 void ConnectionGraph::reduce_phi_on_field_access(Node* previous_addp, GrowableArray<Node *>  &alloc_worklist) {
1088   // We'll pass this to 'split_through_phi' so that it'll do the split even
1089   // though the load doesn't have an unique instance type.
1090   bool ignore_missing_instance_id = true;
1091 
1092   // All AddPs are present in the connection graph
1093   FieldNode* fn = ptnode_adr(previous_addp->_idx)->as_Field();
1094 
1095   // Iterate over AddP looking for a Load
1096   for (int k = previous_addp->outcnt()-1; k >= 0;) {
1097     Node* previous_load = previous_addp->raw_out(k);
1098     if (previous_load->is_Load()) {
1099       Node* data_phi = previous_load->as_Load()->split_through_phi(_igvn, ignore_missing_instance_id);
1100 
1101       // Takes care of updating CG and split_unique_types worklists due to cloned
1102       // AddP->Load.
1103       updates_after_load_split(data_phi, previous_load, alloc_worklist);
1104 
1105       _igvn->replace_node(previous_load, data_phi);
1106     }
1107     --k;
1108     k = MIN2(k, (int)previous_addp->outcnt()-1);
1109   }
1110 
1111   // Remove the old AddP from the processing list because it's dead now
1112   assert(previous_addp->outcnt() == 0, "AddP should be dead now.");
1113   alloc_worklist.remove_if_existing(previous_addp);
1114 }
1115 
1116 // Create a 'selector' Phi based on the inputs of 'ophi'. If index 'i' of the
1117 // selector is:
1118 //    -> a '-1' constant, the i'th input of the original Phi is NSR.
1119 //    -> a 'x' constant >=0, the i'th input of of original Phi will be SR and
1120 //       the info about the scalarized object will be at index x of ObjectMergeValue::possible_objects
1121 PhiNode* ConnectionGraph::create_selector(PhiNode* ophi) const {
1122   Node* minus_one = _igvn->register_new_node_with_optimizer(ConINode::make(-1));
1123   Node* selector  = _igvn->register_new_node_with_optimizer(PhiNode::make(ophi->region(), minus_one, TypeInt::INT));
1124   uint number_of_sr_objects = 0;
1125   for (uint i = 1; i < ophi->req(); i++) {
1126     Node* base = ophi->in(i);
1127     JavaObjectNode* ptn = unique_java_object(base);
1128 
1129     if (ptn != nullptr && ptn->scalar_replaceable()) {
1130       Node* sr_obj_idx = _igvn->register_new_node_with_optimizer(ConINode::make(number_of_sr_objects));
1131       selector->set_req(i, sr_obj_idx);
1132       number_of_sr_objects++;
1133     }
1134   }
1135 
1136   return selector->as_Phi();
1137 }
1138 
1139 // Returns true if the AddP node 'n' has at least one base that is a reducible
1140 // merge. If the base is a CastPP/CheckCastPP then the input of the cast is
1141 // checked instead.
1142 bool ConnectionGraph::has_reducible_merge_base(AddPNode* n, Unique_Node_List &reducible_merges) {
1143   PointsToNode* ptn = ptnode_adr(n->_idx);
1144   if (ptn == nullptr || !ptn->is_Field() || ptn->as_Field()->base_count() < 2) {
1145     return false;
1146   }
1147 
1148   for (BaseIterator i(ptn->as_Field()); i.has_next(); i.next()) {
1149     Node* base = i.get()->ideal_node();
1150 
1151     if (reducible_merges.member(base)) {
1152       return true;
1153     }
1154 
1155     if (base->is_CastPP() || base->is_CheckCastPP()) {
1156       base = base->in(1);
1157       if (reducible_merges.member(base)) {
1158         return true;
1159       }
1160     }
1161   }
1162 
1163   return false;
1164 }
1165 
1166 // This method will call its helper method to reduce SafePoint nodes that use
1167 // 'ophi' or a casted version of 'ophi'. All SafePoint nodes using the same
1168 // "version" of Phi use the same debug information (regarding the Phi).
1169 // Therefore, I collect all safepoints and patch them all at once.
1170 //
1171 // The safepoints using the Phi node have to be processed before safepoints of
1172 // CastPP nodes. The reason is, when reducing a CastPP we add a reference (the
1173 // NSR merge pointer) to the input of the CastPP (i.e., the Phi) in the
1174 // safepoint. If we process CastPP's safepoints before Phi's safepoints the
1175 // algorithm that process Phi's safepoints will think that the added Phi
1176 // reference is a regular reference.
1177 bool ConnectionGraph::reduce_phi_on_safepoints(PhiNode* ophi) {
1178   PhiNode* selector = create_selector(ophi);
1179   Unique_Node_List safepoints;
1180   Unique_Node_List casts;
1181 
1182   // Just collect the users of the Phis for later processing
1183   // in the needed order.
1184   for (uint i = 0; i < ophi->outcnt(); i++) {
1185     Node* use = ophi->raw_out(i);
1186     if (use->is_SafePoint()) {
1187       safepoints.push(use);
1188     } else if (use->is_CastPP()) {
1189       casts.push(use);
1190     } else {
1191       assert(use->outcnt() == 0, "Only CastPP & SafePoint users should be left.");
1192     }
1193   }
1194 
1195   // Need to process safepoints using the Phi first
1196   if (!reduce_phi_on_safepoints_helper(ophi, nullptr, selector, safepoints)) {
1197     return false;
1198   }
1199 
1200   // Now process CastPP->safepoints
1201   for (uint i = 0; i < casts.size(); i++) {
1202     Node* cast = casts.at(i);
1203     Unique_Node_List cast_sfpts;
1204 
1205     for (DUIterator_Fast jmax, j = cast->fast_outs(jmax); j < jmax; j++) {
1206       Node* use_use = cast->fast_out(j);
1207       if (use_use->is_SafePoint()) {
1208         cast_sfpts.push(use_use);
1209       } else {
1210         assert(use_use->outcnt() == 0, "Only SafePoint users should be left.");
1211       }
1212     }
1213 
1214     if (!reduce_phi_on_safepoints_helper(ophi, cast, selector, cast_sfpts)) {
1215       return false;
1216     }
1217   }
1218 
1219   return true;
1220 }
1221 
1222 // This method will create a SafePointScalarMERGEnode for each SafePoint in
1223 // 'safepoints'. It then will iterate on the inputs of 'ophi' and create a
1224 // SafePointScalarObjectNode for each scalar replaceable input. Each
1225 // SafePointScalarMergeNode may describe multiple scalar replaced objects -
1226 // check detailed description in SafePointScalarMergeNode class header.
1227 bool ConnectionGraph::reduce_phi_on_safepoints_helper(Node* ophi, Node* cast, Node* selector, Unique_Node_List& safepoints) {
1228   PhaseMacroExpand mexp(*_igvn);
1229   Node* original_sfpt_parent =  cast != nullptr ? cast : ophi;
1230   const TypeOopPtr* merge_t = _igvn->type(original_sfpt_parent)->make_oopptr();
1231 
1232   Node* nsr_merge_pointer = ophi;
1233   if (cast != nullptr) {
1234     const Type* new_t = merge_t->meet(TypePtr::NULL_PTR);
1235     nsr_merge_pointer = _igvn->transform(ConstraintCastNode::make_cast_for_type(cast->in(0), cast->in(1), new_t, ConstraintCastNode::RegularDependency, nullptr));
1236   }
1237 
1238   for (uint spi = 0; spi < safepoints.size(); spi++) {
1239     SafePointNode* sfpt = safepoints.at(spi)->as_SafePoint();
1240     JVMState *jvms      = sfpt->jvms();
1241     uint merge_idx      = (sfpt->req() - jvms->scloff());
1242     int debug_start     = jvms->debug_start();
1243 
1244     SafePointScalarMergeNode* smerge = new SafePointScalarMergeNode(merge_t, merge_idx);
1245     smerge->init_req(0, _compile->root());
1246     _igvn->register_new_node_with_optimizer(smerge);
1247 
1248     // The next two inputs are:
1249     //  (1) A copy of the original pointer to NSR objects.
1250     //  (2) A selector, used to decide if we need to rematerialize an object
1251     //      or use the pointer to a NSR object.
1252     // See more details of these fields in the declaration of SafePointScalarMergeNode
1253     sfpt->add_req(nsr_merge_pointer);
1254     sfpt->add_req(selector);
1255 
1256     for (uint i = 1; i < ophi->req(); i++) {
1257       Node* base = ophi->in(i);
1258       JavaObjectNode* ptn = unique_java_object(base);
1259 
1260       // If the base is not scalar replaceable we don't need to register information about
1261       // it at this time.
1262       if (ptn == nullptr || !ptn->scalar_replaceable()) {
1263         continue;
1264       }
1265 
1266       AllocateNode* alloc = ptn->ideal_node()->as_Allocate();
1267       Unique_Node_List value_worklist;
1268 #ifdef ASSERT
1269       const Type* res_type = alloc->result_cast()->bottom_type();
1270       if (res_type->is_inlinetypeptr() && !Compile::current()->has_circular_inline_type()) {
1271         PhiNode* phi = ophi->as_Phi();
1272         assert(!ophi->as_Phi()->can_push_inline_types_down(_igvn), "missed earlier scalarization opportunity");
1273       }
1274 #endif
1275       SafePointScalarObjectNode* sobj = mexp.create_scalarized_object_description(alloc, sfpt, &value_worklist);
1276       if (sobj == nullptr) {
1277         _compile->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1278         return false;
1279       }
1280 
1281       // Now make a pass over the debug information replacing any references
1282       // to the allocated object with "sobj"
1283       Node* ccpp = alloc->result_cast();
1284       sfpt->replace_edges_in_range(ccpp, sobj, debug_start, jvms->debug_end(), _igvn);
1285 
1286       // Register the scalarized object as a candidate for reallocation
1287       smerge->add_req(sobj);
1288 
1289       // Scalarize inline types that were added to the safepoint.
1290       // Don't allow linking a constant oop (if available) for flat array elements
1291       // because Deoptimization::reassign_flat_array_elements needs field values.
1292       const bool allow_oop = !merge_t->is_flat();
1293       for (uint j = 0; j < value_worklist.size(); ++j) {
1294         InlineTypeNode* vt = value_worklist.at(j)->as_InlineType();
1295         vt->make_scalar_in_safepoints(_igvn, allow_oop);
1296       }
1297     }
1298 
1299     // Replaces debug information references to "original_sfpt_parent" in "sfpt" with references to "smerge"
1300     sfpt->replace_edges_in_range(original_sfpt_parent, smerge, debug_start, jvms->debug_end(), _igvn);
1301 
1302     // The call to 'replace_edges_in_range' above might have removed the
1303     // reference to ophi that we need at _merge_pointer_idx. The line below make
1304     // sure the reference is maintained.
1305     sfpt->set_req(smerge->merge_pointer_idx(jvms), nsr_merge_pointer);
1306     _igvn->_worklist.push(sfpt);
1307   }
1308 
1309   return true;
1310 }
1311 
1312 void ConnectionGraph::reduce_phi(PhiNode* ophi, GrowableArray<Node *>  &alloc_worklist, GrowableArray<Node *>  &memnode_worklist) {
1313   bool delay = _igvn->delay_transform();
1314   _igvn->set_delay_transform(true);
1315   _igvn->hash_delete(ophi);
1316 
1317   // Copying all users first because some will be removed and others won't.
1318   // Ophi also may acquire some new users as part of Cast reduction.
1319   // CastPPs also need to be processed before CmpPs.
1320   Unique_Node_List castpps;
1321   Unique_Node_List others;
1322   for (DUIterator_Fast imax, i = ophi->fast_outs(imax); i < imax; i++) {
1323     Node* use = ophi->fast_out(i);
1324 
1325     if (use->is_CastPP()) {
1326       castpps.push(use);
1327     } else if (use->is_AddP() || use->is_Cmp()) {
1328       others.push(use);
1329     } else if (use->is_SafePoint()) {
1330       // processed later
1331     } else {
1332       assert(use->is_SafePoint(), "Unexpected user of reducible Phi %d -> %d:%s:%d", ophi->_idx, use->_idx, use->Name(), use->outcnt());
1333     }
1334   }
1335 
1336   // CastPPs need to be processed before Cmps because during the process of
1337   // splitting CastPPs we make reference to the inputs of the Cmp that is used
1338   // by the If controlling the CastPP.
1339   for (uint i = 0; i < castpps.size(); i++) {
1340     reduce_phi_on_castpp_field_load(castpps.at(i), alloc_worklist, memnode_worklist);
1341   }
1342 
1343   for (uint i = 0; i < others.size(); i++) {
1344     Node* use = others.at(i);
1345 
1346     if (use->is_AddP()) {
1347       reduce_phi_on_field_access(use, alloc_worklist);
1348     } else if(use->is_Cmp()) {
1349       reduce_phi_on_cmp(use);
1350     }
1351   }
1352 
1353   _igvn->set_delay_transform(delay);
1354 }
1355 
1356 void ConnectionGraph::reset_scalar_replaceable_entries(PhiNode* ophi) {
1357   Node* null_ptr            = _igvn->makecon(TypePtr::NULL_PTR);
1358   const TypeOopPtr* merge_t = _igvn->type(ophi)->make_oopptr();
1359   const Type* new_t         = merge_t->meet(TypePtr::NULL_PTR);
1360   Node* new_phi             = _igvn->register_new_node_with_optimizer(PhiNode::make(ophi->region(), null_ptr, new_t));
1361 
1362   for (uint i = 1; i < ophi->req(); i++) {
1363     Node* base          = ophi->in(i);
1364     JavaObjectNode* ptn = unique_java_object(base);
1365 
1366     if (ptn != nullptr && ptn->scalar_replaceable()) {
1367       new_phi->set_req(i, null_ptr);
1368     } else {
1369       new_phi->set_req(i, ophi->in(i));
1370     }
1371   }
1372 
1373   for (int i = ophi->outcnt()-1; i >= 0;) {
1374     Node* out = ophi->raw_out(i);
1375 
1376     if (out->is_ConstraintCast()) {
1377       const Type* out_t = _igvn->type(out)->make_ptr();
1378       const Type* out_new_t = out_t->meet(TypePtr::NULL_PTR);
1379       bool change = out_new_t != out_t;
1380 
1381       for (int j = out->outcnt()-1; change && j >= 0; --j) {
1382         Node* out2 = out->raw_out(j);
1383         if (!out2->is_SafePoint()) {
1384           change = false;
1385           break;
1386         }
1387       }
1388 
1389       if (change) {
1390         Node* new_cast = ConstraintCastNode::make_cast_for_type(out->in(0), out->in(1), out_new_t, ConstraintCastNode::StrongDependency, nullptr);
1391         _igvn->replace_node(out, new_cast);
1392         _igvn->register_new_node_with_optimizer(new_cast);
1393       }
1394     }
1395 
1396     --i;
1397     i = MIN2(i, (int)ophi->outcnt()-1);
1398   }
1399 
1400   _igvn->replace_node(ophi, new_phi);
1401 }
1402 
1403 void ConnectionGraph::verify_ram_nodes(Compile* C, Node* root) {
1404   if (!C->do_reduce_allocation_merges()) return;
1405 
1406   Unique_Node_List ideal_nodes;
1407   ideal_nodes.map(C->live_nodes(), nullptr);  // preallocate space
1408   ideal_nodes.push(root);
1409 
1410   for (uint next = 0; next < ideal_nodes.size(); ++next) {
1411     Node* n = ideal_nodes.at(next);
1412 
1413     if (n->is_SafePointScalarMerge()) {
1414       SafePointScalarMergeNode* merge = n->as_SafePointScalarMerge();
1415 
1416       // Validate inputs of merge
1417       for (uint i = 1; i < merge->req(); i++) {
1418         if (merge->in(i) != nullptr && !merge->in(i)->is_top() && !merge->in(i)->is_SafePointScalarObject()) {
1419           assert(false, "SafePointScalarMerge inputs should be null/top or SafePointScalarObject.");
1420           C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1421         }
1422       }
1423 
1424       // Validate users of merge
1425       for (DUIterator_Fast imax, i = merge->fast_outs(imax); i < imax; i++) {
1426         Node* sfpt = merge->fast_out(i);
1427         if (sfpt->is_SafePoint()) {
1428           int merge_idx = merge->merge_pointer_idx(sfpt->as_SafePoint()->jvms());
1429 
1430           if (sfpt->in(merge_idx) != nullptr && sfpt->in(merge_idx)->is_SafePointScalarMerge()) {
1431             assert(false, "SafePointScalarMerge nodes can't be nested.");
1432             C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1433           }
1434         } else {
1435           assert(false, "Only safepoints can use SafePointScalarMerge nodes.");
1436           C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1437         }
1438       }
1439     }
1440 
1441     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1442       Node* m = n->fast_out(i);
1443       ideal_nodes.push(m);
1444     }
1445   }
1446 }
1447 
1448 // Returns true if there is an object in the scope of sfn that does not escape globally.
1449 bool ConnectionGraph::has_ea_local_in_scope(SafePointNode* sfn) {
1450   Compile* C = _compile;
1451   for (JVMState* jvms = sfn->jvms(); jvms != nullptr; jvms = jvms->caller()) {
1452     if (C->env()->should_retain_local_variables() || C->env()->jvmti_can_walk_any_space() ||
1453         DeoptimizeObjectsALot) {
1454       // Jvmti agents can access locals. Must provide info about local objects at runtime.
1455       int num_locs = jvms->loc_size();
1456       for (int idx = 0; idx < num_locs; idx++) {
1457         Node* l = sfn->local(jvms, idx);
1458         if (not_global_escape(l)) {
1459           return true;
1460         }
1461       }
1462     }
1463     if (C->env()->jvmti_can_get_owned_monitor_info() ||
1464         C->env()->jvmti_can_walk_any_space() || DeoptimizeObjectsALot) {
1465       // Jvmti agents can read monitors. Must provide info about locked objects at runtime.
1466       int num_mon = jvms->nof_monitors();
1467       for (int idx = 0; idx < num_mon; idx++) {
1468         Node* m = sfn->monitor_obj(jvms, idx);
1469         if (m != nullptr && not_global_escape(m)) {
1470           return true;
1471         }
1472       }
1473     }
1474   }
1475   return false;
1476 }
1477 
1478 // Returns true if at least one of the arguments to the call is an object
1479 // that does not escape globally.
1480 bool ConnectionGraph::has_arg_escape(CallJavaNode* call) {
1481   if (call->method() != nullptr) {
1482     uint max_idx = TypeFunc::Parms + call->method()->arg_size();
1483     for (uint idx = TypeFunc::Parms; idx < max_idx; idx++) {
1484       Node* p = call->in(idx);
1485       if (not_global_escape(p)) {
1486         return true;
1487       }
1488     }
1489   } else {
1490     const char* name = call->as_CallStaticJava()->_name;
1491     assert(name != nullptr, "no name");
1492     // no arg escapes through uncommon traps
1493     if (strcmp(name, "uncommon_trap") != 0) {
1494       // process_call_arguments() assumes that all arguments escape globally
1495       const TypeTuple* d = call->tf()->domain_sig();
1496       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1497         const Type* at = d->field_at(i);
1498         if (at->isa_oopptr() != nullptr) {
1499           return true;
1500         }
1501       }
1502     }
1503   }
1504   return false;
1505 }
1506 
1507 
1508 
1509 // Utility function for nodes that load an object
1510 void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
1511   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1512   // ThreadLocal has RawPtr type.
1513   const Type* t = _igvn->type(n);
1514   if (t->make_ptr() != nullptr) {
1515     Node* adr = n->in(MemNode::Address);
1516 #ifdef ASSERT
1517     if (!adr->is_AddP()) {
1518       assert(_igvn->type(adr)->isa_rawptr(), "sanity");
1519     } else {
1520       assert((ptnode_adr(adr->_idx) == nullptr ||
1521               ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
1522     }
1523 #endif
1524     add_local_var_and_edge(n, PointsToNode::NoEscape,
1525                            adr, delayed_worklist);
1526   }
1527 }
1528 
1529 // Populate Connection Graph with PointsTo nodes and create simple
1530 // connection graph edges.
1531 void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
1532   assert(!_verify, "this method should not be called for verification");
1533   PhaseGVN* igvn = _igvn;
1534   uint n_idx = n->_idx;
1535   PointsToNode* n_ptn = ptnode_adr(n_idx);
1536   if (n_ptn != nullptr) {
1537     return; // No need to redefine PointsTo node during first iteration.
1538   }
1539   int opcode = n->Opcode();
1540   bool gc_handled = BarrierSet::barrier_set()->barrier_set_c2()->escape_add_to_con_graph(this, igvn, delayed_worklist, n, opcode);
1541   if (gc_handled) {
1542     return; // Ignore node if already handled by GC.
1543   }
1544 
1545   if (n->is_Call()) {
1546     // Arguments to allocation and locking don't escape.
1547     if (n->is_AbstractLock()) {
1548       // Put Lock and Unlock nodes on IGVN worklist to process them during
1549       // first IGVN optimization when escape information is still available.
1550       record_for_optimizer(n);
1551     } else if (n->is_Allocate()) {
1552       add_call_node(n->as_Call());
1553       record_for_optimizer(n);
1554     } else {
1555       if (n->is_CallStaticJava()) {
1556         const char* name = n->as_CallStaticJava()->_name;
1557         if (name != nullptr && strcmp(name, "uncommon_trap") == 0) {
1558           return; // Skip uncommon traps
1559         }
1560       }
1561       // Don't mark as processed since call's arguments have to be processed.
1562       delayed_worklist->push(n);
1563       // Check if a call returns an object.
1564       if ((n->as_Call()->returns_pointer() &&
1565            n->as_Call()->proj_out_or_null(TypeFunc::Parms) != nullptr) ||
1566           (n->is_CallStaticJava() &&
1567            n->as_CallStaticJava()->is_boxing_method())) {
1568         add_call_node(n->as_Call());
1569       } else if (n->as_Call()->tf()->returns_inline_type_as_fields()) {
1570         bool returns_oop = false;
1571         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax && !returns_oop; i++) {
1572           ProjNode* pn = n->fast_out(i)->as_Proj();
1573           if (pn->_con >= TypeFunc::Parms && pn->bottom_type()->isa_ptr()) {
1574             returns_oop = true;
1575           }
1576         }
1577         if (returns_oop) {
1578           add_call_node(n->as_Call());
1579         }
1580       }
1581     }
1582     return;
1583   }
1584   // Put this check here to process call arguments since some call nodes
1585   // point to phantom_obj.
1586   if (n_ptn == phantom_obj || n_ptn == null_obj) {
1587     return; // Skip predefined nodes.
1588   }
1589   switch (opcode) {
1590     case Op_AddP: {
1591       Node* base = get_addp_base(n);
1592       PointsToNode* ptn_base = ptnode_adr(base->_idx);
1593       // Field nodes are created for all field types. They are used in
1594       // adjust_scalar_replaceable_state() and split_unique_types().
1595       // Note, non-oop fields will have only base edges in Connection
1596       // Graph because such fields are not used for oop loads and stores.
1597       int offset = address_offset(n, igvn);
1598       add_field(n, PointsToNode::NoEscape, offset);
1599       if (ptn_base == nullptr) {
1600         delayed_worklist->push(n); // Process it later.
1601       } else {
1602         n_ptn = ptnode_adr(n_idx);
1603         add_base(n_ptn->as_Field(), ptn_base);
1604       }
1605       break;
1606     }
1607     case Op_CastX2P:
1608     case Op_CastI2N: {
1609       map_ideal_node(n, phantom_obj);
1610       break;
1611     }
1612     case Op_InlineType:
1613     case Op_CastPP:
1614     case Op_CheckCastPP:
1615     case Op_EncodeP:
1616     case Op_DecodeN:
1617     case Op_EncodePKlass:
1618     case Op_DecodeNKlass: {
1619       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), delayed_worklist);
1620       break;
1621     }
1622     case Op_CMoveP: {
1623       add_local_var(n, PointsToNode::NoEscape);
1624       // Do not add edges during first iteration because some could be
1625       // not defined yet.
1626       delayed_worklist->push(n);
1627       break;
1628     }
1629     case Op_ConP:
1630     case Op_ConN:
1631     case Op_ConNKlass: {
1632       // assume all oop constants globally escape except for null
1633       PointsToNode::EscapeState es;
1634       const Type* t = igvn->type(n);
1635       if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
1636         es = PointsToNode::NoEscape;
1637       } else {
1638         es = PointsToNode::GlobalEscape;
1639       }
1640       PointsToNode* ptn_con = add_java_object(n, es);
1641       set_not_scalar_replaceable(ptn_con NOT_PRODUCT(COMMA "Constant pointer"));
1642       break;
1643     }
1644     case Op_CreateEx: {
1645       // assume that all exception objects globally escape
1646       map_ideal_node(n, phantom_obj);
1647       break;
1648     }
1649     case Op_LoadKlass:
1650     case Op_LoadNKlass: {
1651       // Unknown class is loaded
1652       map_ideal_node(n, phantom_obj);
1653       break;
1654     }
1655     case Op_LoadP:
1656     case Op_LoadN: {
1657       add_objload_to_connection_graph(n, delayed_worklist);
1658       break;
1659     }
1660     case Op_Parm: {
1661       map_ideal_node(n, phantom_obj);
1662       break;
1663     }
1664     case Op_PartialSubtypeCheck: {
1665       // Produces Null or notNull and is used in only in CmpP so
1666       // phantom_obj could be used.
1667       map_ideal_node(n, phantom_obj); // Result is unknown
1668       break;
1669     }
1670     case Op_Phi: {
1671       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1672       // ThreadLocal has RawPtr type.
1673       const Type* t = n->as_Phi()->type();
1674       if (t->make_ptr() != nullptr) {
1675         add_local_var(n, PointsToNode::NoEscape);
1676         // Do not add edges during first iteration because some could be
1677         // not defined yet.
1678         delayed_worklist->push(n);
1679       }
1680       break;
1681     }
1682     case Op_Proj: {
1683       // we are only interested in the oop result projection from a call
1684       if (n->as_Proj()->_con >= TypeFunc::Parms && n->in(0)->is_Call() &&
1685           (n->in(0)->as_Call()->returns_pointer() || n->bottom_type()->isa_ptr())) {
1686         assert((n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->as_Call()->returns_pointer()) ||
1687                n->in(0)->as_Call()->tf()->returns_inline_type_as_fields(), "what kind of oop return is it?");
1688         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), delayed_worklist);
1689       }
1690       break;
1691     }
1692     case Op_Rethrow: // Exception object escapes
1693     case Op_Return: {
1694       if (n->req() > TypeFunc::Parms &&
1695           igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
1696         // Treat Return value as LocalVar with GlobalEscape escape state.
1697         add_local_var_and_edge(n, PointsToNode::GlobalEscape, n->in(TypeFunc::Parms), delayed_worklist);
1698       }
1699       break;
1700     }
1701     case Op_CompareAndExchangeP:
1702     case Op_CompareAndExchangeN:
1703     case Op_GetAndSetP:
1704     case Op_GetAndSetN: {
1705       add_objload_to_connection_graph(n, delayed_worklist);
1706       // fall-through
1707     }
1708     case Op_StoreP:
1709     case Op_StoreN:
1710     case Op_StoreNKlass:
1711     case Op_WeakCompareAndSwapP:
1712     case Op_WeakCompareAndSwapN:
1713     case Op_CompareAndSwapP:
1714     case Op_CompareAndSwapN: {
1715       add_to_congraph_unsafe_access(n, opcode, delayed_worklist);
1716       break;
1717     }
1718     case Op_AryEq:
1719     case Op_CountPositives:
1720     case Op_StrComp:
1721     case Op_StrEquals:
1722     case Op_StrIndexOf:
1723     case Op_StrIndexOfChar:
1724     case Op_StrInflatedCopy:
1725     case Op_StrCompressedCopy:
1726     case Op_VectorizedHashCode:
1727     case Op_EncodeISOArray: {
1728       add_local_var(n, PointsToNode::ArgEscape);
1729       delayed_worklist->push(n); // Process it later.
1730       break;
1731     }
1732     case Op_ThreadLocal: {
1733       PointsToNode* ptn_thr = add_java_object(n, PointsToNode::ArgEscape);
1734       set_not_scalar_replaceable(ptn_thr NOT_PRODUCT(COMMA "Constant pointer"));
1735       break;
1736     }
1737     case Op_Blackhole: {
1738       // All blackhole pointer arguments are globally escaping.
1739       // Only do this if there is at least one pointer argument.
1740       // Do not add edges during first iteration because some could be
1741       // not defined yet, defer to final step.
1742       for (uint i = 0; i < n->req(); i++) {
1743         Node* in = n->in(i);
1744         if (in != nullptr) {
1745           const Type* at = _igvn->type(in);
1746           if (!at->isa_ptr()) continue;
1747 
1748           add_local_var(n, PointsToNode::GlobalEscape);
1749           delayed_worklist->push(n);
1750           break;
1751         }
1752       }
1753       break;
1754     }
1755     default:
1756       ; // Do nothing for nodes not related to EA.
1757   }
1758   return;
1759 }
1760 
1761 // Add final simple edges to graph.
1762 void ConnectionGraph::add_final_edges(Node *n) {
1763   PointsToNode* n_ptn = ptnode_adr(n->_idx);
1764 #ifdef ASSERT
1765   if (_verify && n_ptn->is_JavaObject())
1766     return; // This method does not change graph for JavaObject.
1767 #endif
1768 
1769   if (n->is_Call()) {
1770     process_call_arguments(n->as_Call());
1771     return;
1772   }
1773   assert(n->is_Store() || n->is_LoadStore() ||
1774          ((n_ptn != nullptr) && (n_ptn->ideal_node() != nullptr)),
1775          "node should be registered already");
1776   int opcode = n->Opcode();
1777   bool gc_handled = BarrierSet::barrier_set()->barrier_set_c2()->escape_add_final_edges(this, _igvn, n, opcode);
1778   if (gc_handled) {
1779     return; // Ignore node if already handled by GC.
1780   }
1781   switch (opcode) {
1782     case Op_AddP: {
1783       Node* base = get_addp_base(n);
1784       PointsToNode* ptn_base = ptnode_adr(base->_idx);
1785       assert(ptn_base != nullptr, "field's base should be registered");
1786       add_base(n_ptn->as_Field(), ptn_base);
1787       break;
1788     }
1789     case Op_InlineType:
1790     case Op_CastPP:
1791     case Op_CheckCastPP:
1792     case Op_EncodeP:
1793     case Op_DecodeN:
1794     case Op_EncodePKlass:
1795     case Op_DecodeNKlass: {
1796       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), nullptr);
1797       break;
1798     }
1799     case Op_CMoveP: {
1800       for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
1801         Node* in = n->in(i);
1802         if (in == nullptr) {
1803           continue;  // ignore null
1804         }
1805         Node* uncast_in = in->uncast();
1806         if (uncast_in->is_top() || uncast_in == n) {
1807           continue;  // ignore top or inputs which go back this node
1808         }
1809         PointsToNode* ptn = ptnode_adr(in->_idx);
1810         assert(ptn != nullptr, "node should be registered");
1811         add_edge(n_ptn, ptn);
1812       }
1813       break;
1814     }
1815     case Op_LoadP:
1816     case Op_LoadN: {
1817       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1818       // ThreadLocal has RawPtr type.
1819       assert(_igvn->type(n)->make_ptr() != nullptr, "Unexpected node type");
1820       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(MemNode::Address), nullptr);
1821       break;
1822     }
1823     case Op_Phi: {
1824       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1825       // ThreadLocal has RawPtr type.
1826       assert(n->as_Phi()->type()->make_ptr() != nullptr, "Unexpected node type");
1827       for (uint i = 1; i < n->req(); i++) {
1828         Node* in = n->in(i);
1829         if (in == nullptr) {
1830           continue;  // ignore null
1831         }
1832         Node* uncast_in = in->uncast();
1833         if (uncast_in->is_top() || uncast_in == n) {
1834           continue;  // ignore top or inputs which go back this node
1835         }
1836         PointsToNode* ptn = ptnode_adr(in->_idx);
1837         assert(ptn != nullptr, "node should be registered");
1838         add_edge(n_ptn, ptn);
1839       }
1840       break;
1841     }
1842     case Op_Proj: {
1843       // we are only interested in the oop result projection from a call
1844       assert((n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->as_Call()->returns_pointer()) ||
1845              n->in(0)->as_Call()->tf()->returns_inline_type_as_fields(), "what kind of oop return is it?");
1846       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), nullptr);
1847       break;
1848     }
1849     case Op_Rethrow: // Exception object escapes
1850     case Op_Return: {
1851       assert(n->req() > TypeFunc::Parms && _igvn->type(n->in(TypeFunc::Parms))->isa_oopptr(),
1852              "Unexpected node type");
1853       // Treat Return value as LocalVar with GlobalEscape escape state.
1854       add_local_var_and_edge(n, PointsToNode::GlobalEscape, n->in(TypeFunc::Parms), nullptr);
1855       break;
1856     }
1857     case Op_CompareAndExchangeP:
1858     case Op_CompareAndExchangeN:
1859     case Op_GetAndSetP:
1860     case Op_GetAndSetN:{
1861       assert(_igvn->type(n)->make_ptr() != nullptr, "Unexpected node type");
1862       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(MemNode::Address), nullptr);
1863       // fall-through
1864     }
1865     case Op_CompareAndSwapP:
1866     case Op_CompareAndSwapN:
1867     case Op_WeakCompareAndSwapP:
1868     case Op_WeakCompareAndSwapN:
1869     case Op_StoreP:
1870     case Op_StoreN:
1871     case Op_StoreNKlass:{
1872       add_final_edges_unsafe_access(n, opcode);
1873       break;
1874     }
1875     case Op_VectorizedHashCode:
1876     case Op_AryEq:
1877     case Op_CountPositives:
1878     case Op_StrComp:
1879     case Op_StrEquals:
1880     case Op_StrIndexOf:
1881     case Op_StrIndexOfChar:
1882     case Op_StrInflatedCopy:
1883     case Op_StrCompressedCopy:
1884     case Op_EncodeISOArray: {
1885       // char[]/byte[] arrays passed to string intrinsic do not escape but
1886       // they are not scalar replaceable. Adjust escape state for them.
1887       // Start from in(2) edge since in(1) is memory edge.
1888       for (uint i = 2; i < n->req(); i++) {
1889         Node* adr = n->in(i);
1890         const Type* at = _igvn->type(adr);
1891         if (!adr->is_top() && at->isa_ptr()) {
1892           assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
1893                  at->isa_ptr() != nullptr, "expecting a pointer");
1894           if (adr->is_AddP()) {
1895             adr = get_addp_base(adr);
1896           }
1897           PointsToNode* ptn = ptnode_adr(adr->_idx);
1898           assert(ptn != nullptr, "node should be registered");
1899           add_edge(n_ptn, ptn);
1900         }
1901       }
1902       break;
1903     }
1904     case Op_Blackhole: {
1905       // All blackhole pointer arguments are globally escaping.
1906       for (uint i = 0; i < n->req(); i++) {
1907         Node* in = n->in(i);
1908         if (in != nullptr) {
1909           const Type* at = _igvn->type(in);
1910           if (!at->isa_ptr()) continue;
1911 
1912           if (in->is_AddP()) {
1913             in = get_addp_base(in);
1914           }
1915 
1916           PointsToNode* ptn = ptnode_adr(in->_idx);
1917           assert(ptn != nullptr, "should be defined already");
1918           set_escape_state(ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA "blackhole"));
1919           add_edge(n_ptn, ptn);
1920         }
1921       }
1922       break;
1923     }
1924     default: {
1925       // This method should be called only for EA specific nodes which may
1926       // miss some edges when they were created.
1927 #ifdef ASSERT
1928       n->dump(1);
1929 #endif
1930       guarantee(false, "unknown node");
1931     }
1932   }
1933   return;
1934 }
1935 
1936 void ConnectionGraph::add_to_congraph_unsafe_access(Node* n, uint opcode, Unique_Node_List* delayed_worklist) {
1937   Node* adr = n->in(MemNode::Address);
1938   const Type* adr_type = _igvn->type(adr);
1939   adr_type = adr_type->make_ptr();
1940   if (adr_type == nullptr) {
1941     return; // skip dead nodes
1942   }
1943   if (adr_type->isa_oopptr()
1944       || ((opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass)
1945           && adr_type == TypeRawPtr::NOTNULL
1946           && is_captured_store_address(adr))) {
1947     delayed_worklist->push(n); // Process it later.
1948 #ifdef ASSERT
1949     assert (adr->is_AddP(), "expecting an AddP");
1950     if (adr_type == TypeRawPtr::NOTNULL) {
1951       // Verify a raw address for a store captured by Initialize node.
1952       int offs = (int) _igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
1953       assert(offs != Type::OffsetBot, "offset must be a constant");
1954     }
1955 #endif
1956   } else {
1957     // Ignore copy the displaced header to the BoxNode (OSR compilation).
1958     if (adr->is_BoxLock()) {
1959       return;
1960     }
1961     // Stored value escapes in unsafe access.
1962     if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
1963       delayed_worklist->push(n); // Process unsafe access later.
1964       return;
1965     }
1966 #ifdef ASSERT
1967     n->dump(1);
1968     assert(false, "not unsafe");
1969 #endif
1970   }
1971 }
1972 
1973 bool ConnectionGraph::add_final_edges_unsafe_access(Node* n, uint opcode) {
1974   Node* adr = n->in(MemNode::Address);
1975   const Type *adr_type = _igvn->type(adr);
1976   adr_type = adr_type->make_ptr();
1977 #ifdef ASSERT
1978   if (adr_type == nullptr) {
1979     n->dump(1);
1980     assert(adr_type != nullptr, "dead node should not be on list");
1981     return true;
1982   }
1983 #endif
1984 
1985   if (adr_type->isa_oopptr()
1986       || ((opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass)
1987            && adr_type == TypeRawPtr::NOTNULL
1988            && is_captured_store_address(adr))) {
1989     // Point Address to Value
1990     PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
1991     assert(adr_ptn != nullptr &&
1992            adr_ptn->as_Field()->is_oop(), "node should be registered");
1993     Node* val = n->in(MemNode::ValueIn);
1994     PointsToNode* ptn = ptnode_adr(val->_idx);
1995     assert(ptn != nullptr, "node should be registered");
1996     add_edge(adr_ptn, ptn);
1997     return true;
1998   } else if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
1999     // Stored value escapes in unsafe access.
2000     Node* val = n->in(MemNode::ValueIn);
2001     PointsToNode* ptn = ptnode_adr(val->_idx);
2002     assert(ptn != nullptr, "node should be registered");
2003     set_escape_state(ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA "stored at raw address"));
2004     // Add edge to object for unsafe access with offset.
2005     PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
2006     assert(adr_ptn != nullptr, "node should be registered");
2007     if (adr_ptn->is_Field()) {
2008       assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
2009       add_edge(adr_ptn, ptn);
2010     }
2011     return true;
2012   }
2013 #ifdef ASSERT
2014   n->dump(1);
2015   assert(false, "not unsafe");
2016 #endif
2017   return false;
2018 }
2019 
2020 void ConnectionGraph::add_call_node(CallNode* call) {
2021   assert(call->returns_pointer() || call->tf()->returns_inline_type_as_fields(), "only for call which returns pointer");
2022   uint call_idx = call->_idx;
2023   if (call->is_Allocate()) {
2024     Node* k = call->in(AllocateNode::KlassNode);
2025     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
2026     assert(kt != nullptr, "TypeKlassPtr  required.");
2027     PointsToNode::EscapeState es = PointsToNode::NoEscape;
2028     bool scalar_replaceable = true;
2029     NOT_PRODUCT(const char* nsr_reason = "");
2030     if (call->is_AllocateArray()) {
2031       if (!kt->isa_aryklassptr()) { // StressReflectiveCode
2032         es = PointsToNode::GlobalEscape;
2033       } else {
2034         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
2035         if (length < 0) {
2036           // Not scalar replaceable if the length is not constant.
2037           scalar_replaceable = false;
2038           NOT_PRODUCT(nsr_reason = "has a non-constant length");
2039         } else if (length > EliminateAllocationArraySizeLimit) {
2040           // Not scalar replaceable if the length is too big.
2041           scalar_replaceable = false;
2042           NOT_PRODUCT(nsr_reason = "has a length that is too big");
2043         }
2044       }
2045     } else {  // Allocate instance
2046       if (!kt->isa_instklassptr()) { // StressReflectiveCode
2047         es = PointsToNode::GlobalEscape;
2048       } else {
2049         const TypeInstKlassPtr* ikt = kt->is_instklassptr();
2050         ciInstanceKlass* ik = ikt->klass_is_exact() ? ikt->exact_klass()->as_instance_klass() : ikt->instance_klass();
2051         if (ik->is_subclass_of(_compile->env()->Thread_klass()) ||
2052             ik->is_subclass_of(_compile->env()->Reference_klass()) ||
2053             !ik->can_be_instantiated() ||
2054             ik->has_finalizer()) {
2055           es = PointsToNode::GlobalEscape;
2056         } else {
2057           int nfields = ik->as_instance_klass()->nof_nonstatic_fields();
2058           if (nfields > EliminateAllocationFieldsLimit) {
2059             // Not scalar replaceable if there are too many fields.
2060             scalar_replaceable = false;
2061             NOT_PRODUCT(nsr_reason = "has too many fields");
2062           }
2063         }
2064       }
2065     }
2066     add_java_object(call, es);
2067     PointsToNode* ptn = ptnode_adr(call_idx);
2068     if (!scalar_replaceable && ptn->scalar_replaceable()) {
2069       set_not_scalar_replaceable(ptn NOT_PRODUCT(COMMA nsr_reason));
2070     }
2071   } else if (call->is_CallStaticJava()) {
2072     // Call nodes could be different types:
2073     //
2074     // 1. CallDynamicJavaNode (what happened during call is unknown):
2075     //
2076     //    - mapped to GlobalEscape JavaObject node if oop is returned;
2077     //
2078     //    - all oop arguments are escaping globally;
2079     //
2080     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
2081     //
2082     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
2083     //
2084     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
2085     //    - mapped to NoEscape JavaObject node if non-escaping object allocated
2086     //      during call is returned;
2087     //    - mapped to ArgEscape LocalVar node pointed to object arguments
2088     //      which are returned and does not escape during call;
2089     //
2090     //    - oop arguments escaping status is defined by bytecode analysis;
2091     //
2092     // For a static call, we know exactly what method is being called.
2093     // Use bytecode estimator to record whether the call's return value escapes.
2094     ciMethod* meth = call->as_CallJava()->method();
2095     if (meth == nullptr) {
2096       const char* name = call->as_CallStaticJava()->_name;
2097       assert(strncmp(name, "C2 Runtime multianewarray", 25) == 0 ||
2098              strncmp(name, "C2 Runtime load_unknown_inline", 30) == 0, "TODO: add failed case check");
2099       // Returns a newly allocated non-escaped object.
2100       add_java_object(call, PointsToNode::NoEscape);
2101       set_not_scalar_replaceable(ptnode_adr(call_idx) NOT_PRODUCT(COMMA "is result of multinewarray"));
2102     } else if (meth->is_boxing_method()) {
2103       // Returns boxing object
2104       PointsToNode::EscapeState es;
2105       vmIntrinsics::ID intr = meth->intrinsic_id();
2106       if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
2107         // It does not escape if object is always allocated.
2108         es = PointsToNode::NoEscape;
2109       } else {
2110         // It escapes globally if object could be loaded from cache.
2111         es = PointsToNode::GlobalEscape;
2112       }
2113       add_java_object(call, es);
2114       if (es == PointsToNode::GlobalEscape) {
2115         set_not_scalar_replaceable(ptnode_adr(call->_idx) NOT_PRODUCT(COMMA "object can be loaded from boxing cache"));
2116       }
2117     } else {
2118       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
2119       call_analyzer->copy_dependencies(_compile->dependencies());
2120       if (call_analyzer->is_return_allocated()) {
2121         // Returns a newly allocated non-escaped object, simply
2122         // update dependency information.
2123         // Mark it as NoEscape so that objects referenced by
2124         // it's fields will be marked as NoEscape at least.
2125         add_java_object(call, PointsToNode::NoEscape);
2126         set_not_scalar_replaceable(ptnode_adr(call_idx) NOT_PRODUCT(COMMA "is result of call"));
2127       } else {
2128         // Determine whether any arguments are returned.
2129         const TypeTuple* d = call->tf()->domain_cc();
2130         bool ret_arg = false;
2131         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2132           if (d->field_at(i)->isa_ptr() != nullptr &&
2133               call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
2134             ret_arg = true;
2135             break;
2136           }
2137         }
2138         if (ret_arg) {
2139           add_local_var(call, PointsToNode::ArgEscape);
2140         } else {
2141           // Returns unknown object.
2142           map_ideal_node(call, phantom_obj);
2143         }
2144       }
2145     }
2146   } else {
2147     // An other type of call, assume the worst case:
2148     // returned value is unknown and globally escapes.
2149     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
2150     map_ideal_node(call, phantom_obj);
2151   }
2152 }
2153 
2154 void ConnectionGraph::process_call_arguments(CallNode *call) {
2155     bool is_arraycopy = false;
2156     switch (call->Opcode()) {
2157 #ifdef ASSERT
2158     case Op_Allocate:
2159     case Op_AllocateArray:
2160     case Op_Lock:
2161     case Op_Unlock:
2162       assert(false, "should be done already");
2163       break;
2164 #endif
2165     case Op_ArrayCopy:
2166     case Op_CallLeafNoFP:
2167       // Most array copies are ArrayCopy nodes at this point but there
2168       // are still a few direct calls to the copy subroutines (See
2169       // PhaseStringOpts::copy_string())
2170       is_arraycopy = (call->Opcode() == Op_ArrayCopy) ||
2171         call->as_CallLeaf()->is_call_to_arraycopystub();
2172       // fall through
2173     case Op_CallLeafVector:
2174     case Op_CallLeaf: {
2175       // Stub calls, objects do not escape but they are not scale replaceable.
2176       // Adjust escape state for outgoing arguments.
2177       const TypeTuple * d = call->tf()->domain_sig();
2178       bool src_has_oops = false;
2179       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2180         const Type* at = d->field_at(i);
2181         Node *arg = call->in(i);
2182         if (arg == nullptr) {
2183           continue;
2184         }
2185         const Type *aat = _igvn->type(arg);
2186         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr()) {
2187           continue;
2188         }
2189         if (arg->is_AddP()) {
2190           //
2191           // The inline_native_clone() case when the arraycopy stub is called
2192           // after the allocation before Initialize and CheckCastPP nodes.
2193           // Or normal arraycopy for object arrays case.
2194           //
2195           // Set AddP's base (Allocate) as not scalar replaceable since
2196           // pointer to the base (with offset) is passed as argument.
2197           //
2198           arg = get_addp_base(arg);
2199         }
2200         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
2201         assert(arg_ptn != nullptr, "should be registered");
2202         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
2203         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
2204           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
2205                  aat->isa_ptr() != nullptr, "expecting an Ptr");
2206           bool arg_has_oops = aat->isa_oopptr() &&
2207                               (aat->isa_instptr() ||
2208                                (aat->isa_aryptr() && (aat->isa_aryptr()->elem() == Type::BOTTOM || aat->isa_aryptr()->elem()->make_oopptr() != nullptr)) ||
2209                                (aat->isa_aryptr() && aat->isa_aryptr()->elem() != nullptr &&
2210                                                                aat->isa_aryptr()->is_flat() &&
2211                                                                aat->isa_aryptr()->elem()->inline_klass()->contains_oops()));
2212           if (i == TypeFunc::Parms) {
2213             src_has_oops = arg_has_oops;
2214           }
2215           //
2216           // src or dst could be j.l.Object when other is basic type array:
2217           //
2218           //   arraycopy(char[],0,Object*,0,size);
2219           //   arraycopy(Object*,0,char[],0,size);
2220           //
2221           // Don't add edges in such cases.
2222           //
2223           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
2224                                        arg_has_oops && (i > TypeFunc::Parms);
2225 #ifdef ASSERT
2226           if (!(is_arraycopy ||
2227                 BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(call) ||
2228                 (call->as_CallLeaf()->_name != nullptr &&
2229                  (strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
2230                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32C") == 0 ||
2231                   strcmp(call->as_CallLeaf()->_name, "updateBytesAdler32") == 0 ||
2232                   strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
2233                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
2234                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
2235                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
2236                   strcmp(call->as_CallLeaf()->_name, "electronicCodeBook_encryptAESCrypt") == 0 ||
2237                   strcmp(call->as_CallLeaf()->_name, "electronicCodeBook_decryptAESCrypt") == 0 ||
2238                   strcmp(call->as_CallLeaf()->_name, "counterMode_AESCrypt") == 0 ||
2239                   strcmp(call->as_CallLeaf()->_name, "galoisCounterMode_AESCrypt") == 0 ||
2240                   strcmp(call->as_CallLeaf()->_name, "poly1305_processBlocks") == 0 ||
2241                   strcmp(call->as_CallLeaf()->_name, "intpoly_montgomeryMult_P256") == 0 ||
2242                   strcmp(call->as_CallLeaf()->_name, "intpoly_assign") == 0 ||
2243                   strcmp(call->as_CallLeaf()->_name, "ghash_processBlocks") == 0 ||
2244                   strcmp(call->as_CallLeaf()->_name, "chacha20Block") == 0 ||
2245                   strcmp(call->as_CallLeaf()->_name, "kyberNtt") == 0 ||
2246                   strcmp(call->as_CallLeaf()->_name, "kyberInverseNtt") == 0 ||
2247                   strcmp(call->as_CallLeaf()->_name, "kyberNttMult") == 0 ||
2248                   strcmp(call->as_CallLeaf()->_name, "kyberAddPoly_2") == 0 ||
2249                   strcmp(call->as_CallLeaf()->_name, "kyberAddPoly_3") == 0 ||
2250                   strcmp(call->as_CallLeaf()->_name, "kyber12To16") == 0 ||
2251                   strcmp(call->as_CallLeaf()->_name, "kyberBarrettReduce") == 0 ||
2252                   strcmp(call->as_CallLeaf()->_name, "dilithiumAlmostNtt") == 0 ||
2253                   strcmp(call->as_CallLeaf()->_name, "dilithiumAlmostInverseNtt") == 0 ||
2254                   strcmp(call->as_CallLeaf()->_name, "dilithiumNttMult") == 0 ||
2255                   strcmp(call->as_CallLeaf()->_name, "dilithiumMontMulByConstant") == 0 ||
2256                   strcmp(call->as_CallLeaf()->_name, "dilithiumDecomposePoly") == 0 ||
2257                   strcmp(call->as_CallLeaf()->_name, "encodeBlock") == 0 ||
2258                   strcmp(call->as_CallLeaf()->_name, "decodeBlock") == 0 ||
2259                   strcmp(call->as_CallLeaf()->_name, "md5_implCompress") == 0 ||
2260                   strcmp(call->as_CallLeaf()->_name, "md5_implCompressMB") == 0 ||
2261                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
2262                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
2263                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
2264                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
2265                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
2266                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
2267                   strcmp(call->as_CallLeaf()->_name, "sha3_implCompress") == 0 ||
2268                   strcmp(call->as_CallLeaf()->_name, "double_keccak") == 0 ||
2269                   strcmp(call->as_CallLeaf()->_name, "sha3_implCompressMB") == 0 ||
2270                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
2271                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
2272                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0 ||
2273                   strcmp(call->as_CallLeaf()->_name, "montgomery_multiply") == 0 ||
2274                   strcmp(call->as_CallLeaf()->_name, "montgomery_square") == 0 ||
2275                   strcmp(call->as_CallLeaf()->_name, "vectorizedMismatch") == 0 ||
2276                   strcmp(call->as_CallLeaf()->_name, "load_unknown_inline") == 0 ||
2277                   strcmp(call->as_CallLeaf()->_name, "store_unknown_inline") == 0 ||
2278                   strcmp(call->as_CallLeaf()->_name, "bigIntegerRightShiftWorker") == 0 ||
2279                   strcmp(call->as_CallLeaf()->_name, "bigIntegerLeftShiftWorker") == 0 ||
2280                   strcmp(call->as_CallLeaf()->_name, "vectorizedMismatch") == 0 ||
2281                   strcmp(call->as_CallLeaf()->_name, "stringIndexOf") == 0 ||
2282                   strcmp(call->as_CallLeaf()->_name, "arraysort_stub") == 0 ||
2283                   strcmp(call->as_CallLeaf()->_name, "array_partition_stub") == 0 ||
2284                   strcmp(call->as_CallLeaf()->_name, "get_class_id_intrinsic") == 0 ||
2285                   strcmp(call->as_CallLeaf()->_name, "unsafe_setmemory") == 0)
2286                  ))) {
2287             call->dump();
2288             fatal("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name);
2289           }
2290 #endif
2291           // Always process arraycopy's destination object since
2292           // we need to add all possible edges to references in
2293           // source object.
2294           if (arg_esc >= PointsToNode::ArgEscape &&
2295               !arg_is_arraycopy_dest) {
2296             continue;
2297           }
2298           PointsToNode::EscapeState es = PointsToNode::ArgEscape;
2299           if (call->is_ArrayCopy()) {
2300             ArrayCopyNode* ac = call->as_ArrayCopy();
2301             if (ac->is_clonebasic() ||
2302                 ac->is_arraycopy_validated() ||
2303                 ac->is_copyof_validated() ||
2304                 ac->is_copyofrange_validated()) {
2305               es = PointsToNode::NoEscape;
2306             }
2307           }
2308           set_escape_state(arg_ptn, es NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2309           if (arg_is_arraycopy_dest) {
2310             Node* src = call->in(TypeFunc::Parms);
2311             if (src->is_AddP()) {
2312               src = get_addp_base(src);
2313             }
2314             PointsToNode* src_ptn = ptnode_adr(src->_idx);
2315             assert(src_ptn != nullptr, "should be registered");
2316             if (arg_ptn != src_ptn) {
2317               // Special arraycopy edge:
2318               // A destination object's field can't have the source object
2319               // as base since objects escape states are not related.
2320               // Only escape state of destination object's fields affects
2321               // escape state of fields in source object.
2322               add_arraycopy(call, es, src_ptn, arg_ptn);
2323             }
2324           }
2325         }
2326       }
2327       break;
2328     }
2329     case Op_CallStaticJava: {
2330       // For a static call, we know exactly what method is being called.
2331       // Use bytecode estimator to record the call's escape affects
2332 #ifdef ASSERT
2333       const char* name = call->as_CallStaticJava()->_name;
2334       assert((name == nullptr || strcmp(name, "uncommon_trap") != 0), "normal calls only");
2335 #endif
2336       ciMethod* meth = call->as_CallJava()->method();
2337       if ((meth != nullptr) && meth->is_boxing_method()) {
2338         break; // Boxing methods do not modify any oops.
2339       }
2340       BCEscapeAnalyzer* call_analyzer = (meth !=nullptr) ? meth->get_bcea() : nullptr;
2341       // fall-through if not a Java method or no analyzer information
2342       if (call_analyzer != nullptr) {
2343         PointsToNode* call_ptn = ptnode_adr(call->_idx);
2344         const TypeTuple* d = call->tf()->domain_cc();
2345         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2346           const Type* at = d->field_at(i);
2347           int k = i - TypeFunc::Parms;
2348           Node* arg = call->in(i);
2349           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
2350           if (at->isa_ptr() != nullptr &&
2351               call_analyzer->is_arg_returned(k)) {
2352             // The call returns arguments.
2353             if (call_ptn != nullptr) { // Is call's result used?
2354               assert(call_ptn->is_LocalVar(), "node should be registered");
2355               assert(arg_ptn != nullptr, "node should be registered");
2356               add_edge(call_ptn, arg_ptn);
2357             }
2358           }
2359           if (at->isa_oopptr() != nullptr &&
2360               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
2361             if (!call_analyzer->is_arg_stack(k)) {
2362               // The argument global escapes
2363               set_escape_state(arg_ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2364             } else {
2365               set_escape_state(arg_ptn, PointsToNode::ArgEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2366               if (!call_analyzer->is_arg_local(k)) {
2367                 // The argument itself doesn't escape, but any fields might
2368                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2369               }
2370             }
2371           }
2372         }
2373         if (call_ptn != nullptr && call_ptn->is_LocalVar()) {
2374           // The call returns arguments.
2375           assert(call_ptn->edge_count() > 0, "sanity");
2376           if (!call_analyzer->is_return_local()) {
2377             // Returns also unknown object.
2378             add_edge(call_ptn, phantom_obj);
2379           }
2380         }
2381         break;
2382       }
2383     }
2384     default: {
2385       // Fall-through here if not a Java method or no analyzer information
2386       // or some other type of call, assume the worst case: all arguments
2387       // globally escape.
2388       const TypeTuple* d = call->tf()->domain_cc();
2389       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2390         const Type* at = d->field_at(i);
2391         if (at->isa_oopptr() != nullptr) {
2392           Node* arg = call->in(i);
2393           if (arg->is_AddP()) {
2394             arg = get_addp_base(arg);
2395           }
2396           assert(ptnode_adr(arg->_idx) != nullptr, "should be defined already");
2397           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2398         }
2399       }
2400     }
2401   }
2402 }
2403 
2404 
2405 // Finish Graph construction.
2406 bool ConnectionGraph::complete_connection_graph(
2407                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
2408                          GrowableArray<JavaObjectNode*>& non_escaped_allocs_worklist,
2409                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
2410                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
2411   // Normally only 1-3 passes needed to build Connection Graph depending
2412   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
2413   // Set limit to 20 to catch situation when something did go wrong and
2414   // bailout Escape Analysis.
2415   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
2416 #define GRAPH_BUILD_ITER_LIMIT 20
2417 
2418   // Propagate GlobalEscape and ArgEscape escape states and check that
2419   // we still have non-escaping objects. The method pushs on _worklist
2420   // Field nodes which reference phantom_object.
2421   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_allocs_worklist)) {
2422     return false; // Nothing to do.
2423   }
2424   // Now propagate references to all JavaObject nodes.
2425   int java_objects_length = java_objects_worklist.length();
2426   elapsedTimer build_time;
2427   build_time.start();
2428   elapsedTimer time;
2429   bool timeout = false;
2430   int new_edges = 1;
2431   int iterations = 0;
2432   do {
2433     while ((new_edges > 0) &&
2434            (iterations++ < GRAPH_BUILD_ITER_LIMIT)) {
2435       double start_time = time.seconds();
2436       time.start();
2437       new_edges = 0;
2438       // Propagate references to phantom_object for nodes pushed on _worklist
2439       // by find_non_escaped_objects() and find_field_value().
2440       new_edges += add_java_object_edges(phantom_obj, false);
2441       for (int next = 0; next < java_objects_length; ++next) {
2442         JavaObjectNode* ptn = java_objects_worklist.at(next);
2443         new_edges += add_java_object_edges(ptn, true);
2444 
2445 #define SAMPLE_SIZE 4
2446         if ((next % SAMPLE_SIZE) == 0) {
2447           // Each 4 iterations calculate how much time it will take
2448           // to complete graph construction.
2449           time.stop();
2450           // Poll for requests from shutdown mechanism to quiesce compiler
2451           // because Connection graph construction may take long time.
2452           CompileBroker::maybe_block();
2453           double stop_time = time.seconds();
2454           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
2455           double time_until_end = time_per_iter * (double)(java_objects_length - next);
2456           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
2457             timeout = true;
2458             break; // Timeout
2459           }
2460           start_time = stop_time;
2461           time.start();
2462         }
2463 #undef SAMPLE_SIZE
2464 
2465       }
2466       if (timeout) break;
2467       if (new_edges > 0) {
2468         // Update escape states on each iteration if graph was updated.
2469         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_allocs_worklist)) {
2470           return false; // Nothing to do.
2471         }
2472       }
2473       time.stop();
2474       if (time.seconds() >= EscapeAnalysisTimeout) {
2475         timeout = true;
2476         break;
2477       }
2478     }
2479     if ((iterations < GRAPH_BUILD_ITER_LIMIT) && !timeout) {
2480       time.start();
2481       // Find fields which have unknown value.
2482       int fields_length = oop_fields_worklist.length();
2483       for (int next = 0; next < fields_length; next++) {
2484         FieldNode* field = oop_fields_worklist.at(next);
2485         if (field->edge_count() == 0) {
2486           new_edges += find_field_value(field);
2487           // This code may added new edges to phantom_object.
2488           // Need an other cycle to propagate references to phantom_object.
2489         }
2490       }
2491       time.stop();
2492       if (time.seconds() >= EscapeAnalysisTimeout) {
2493         timeout = true;
2494         break;
2495       }
2496     } else {
2497       new_edges = 0; // Bailout
2498     }
2499   } while (new_edges > 0);
2500 
2501   build_time.stop();
2502   _build_time = build_time.seconds();
2503   _build_iterations = iterations;
2504 
2505   // Bailout if passed limits.
2506   if ((iterations >= GRAPH_BUILD_ITER_LIMIT) || timeout) {
2507     Compile* C = _compile;
2508     if (C->log() != nullptr) {
2509       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
2510       C->log()->text("%s", timeout ? "time" : "iterations");
2511       C->log()->end_elem(" limit'");
2512     }
2513     assert(ExitEscapeAnalysisOnTimeout, "infinite EA connection graph build during invocation %d (%f sec, %d iterations) with %d nodes and worklist size %d",
2514            _invocation, _build_time, _build_iterations, nodes_size(), ptnodes_worklist.length());
2515     // Possible infinite build_connection_graph loop,
2516     // bailout (no changes to ideal graph were made).
2517     return false;
2518   }
2519 
2520 #undef GRAPH_BUILD_ITER_LIMIT
2521 
2522   // Find fields initialized by null for non-escaping Allocations.
2523   int non_escaped_length = non_escaped_allocs_worklist.length();
2524   for (int next = 0; next < non_escaped_length; next++) {
2525     JavaObjectNode* ptn = non_escaped_allocs_worklist.at(next);
2526     PointsToNode::EscapeState es = ptn->escape_state();
2527     assert(es <= PointsToNode::ArgEscape, "sanity");
2528     if (es == PointsToNode::NoEscape) {
2529       if (find_init_values_null(ptn, _igvn) > 0) {
2530         // Adding references to null object does not change escape states
2531         // since it does not escape. Also no fields are added to null object.
2532         add_java_object_edges(null_obj, false);
2533       }
2534     }
2535     Node* n = ptn->ideal_node();
2536     if (n->is_Allocate()) {
2537       // The object allocated by this Allocate node will never be
2538       // seen by an other thread. Mark it so that when it is
2539       // expanded no MemBarStoreStore is added.
2540       InitializeNode* ini = n->as_Allocate()->initialization();
2541       if (ini != nullptr)
2542         ini->set_does_not_escape();
2543     }
2544   }
2545   return true; // Finished graph construction.
2546 }
2547 
2548 // Propagate GlobalEscape and ArgEscape escape states to all nodes
2549 // and check that we still have non-escaping java objects.
2550 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
2551                                                GrowableArray<JavaObjectNode*>& non_escaped_allocs_worklist) {
2552   GrowableArray<PointsToNode*> escape_worklist;
2553   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
2554   int ptnodes_length = ptnodes_worklist.length();
2555   for (int next = 0; next < ptnodes_length; ++next) {
2556     PointsToNode* ptn = ptnodes_worklist.at(next);
2557     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
2558         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
2559       escape_worklist.push(ptn);
2560     }
2561   }
2562   // Set escape states to referenced nodes (edges list).
2563   while (escape_worklist.length() > 0) {
2564     PointsToNode* ptn = escape_worklist.pop();
2565     PointsToNode::EscapeState es  = ptn->escape_state();
2566     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
2567     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
2568         es >= PointsToNode::ArgEscape) {
2569       // GlobalEscape or ArgEscape state of field means it has unknown value.
2570       if (add_edge(ptn, phantom_obj)) {
2571         // New edge was added
2572         add_field_uses_to_worklist(ptn->as_Field());
2573       }
2574     }
2575     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2576       PointsToNode* e = i.get();
2577       if (e->is_Arraycopy()) {
2578         assert(ptn->arraycopy_dst(), "sanity");
2579         // Propagate only fields escape state through arraycopy edge.
2580         if (e->fields_escape_state() < field_es) {
2581           set_fields_escape_state(e, field_es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2582           escape_worklist.push(e);
2583         }
2584       } else if (es >= field_es) {
2585         // fields_escape_state is also set to 'es' if it is less than 'es'.
2586         if (e->escape_state() < es) {
2587           set_escape_state(e, es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2588           escape_worklist.push(e);
2589         }
2590       } else {
2591         // Propagate field escape state.
2592         bool es_changed = false;
2593         if (e->fields_escape_state() < field_es) {
2594           set_fields_escape_state(e, field_es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2595           es_changed = true;
2596         }
2597         if ((e->escape_state() < field_es) &&
2598             e->is_Field() && ptn->is_JavaObject() &&
2599             e->as_Field()->is_oop()) {
2600           // Change escape state of referenced fields.
2601           set_escape_state(e, field_es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2602           es_changed = true;
2603         } else if (e->escape_state() < es) {
2604           set_escape_state(e, es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2605           es_changed = true;
2606         }
2607         if (es_changed) {
2608           escape_worklist.push(e);
2609         }
2610       }
2611     }
2612   }
2613   // Remove escaped objects from non_escaped list.
2614   for (int next = non_escaped_allocs_worklist.length()-1; next >= 0 ; --next) {
2615     JavaObjectNode* ptn = non_escaped_allocs_worklist.at(next);
2616     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
2617       non_escaped_allocs_worklist.delete_at(next);
2618     }
2619     if (ptn->escape_state() == PointsToNode::NoEscape) {
2620       // Find fields in non-escaped allocations which have unknown value.
2621       find_init_values_phantom(ptn);
2622     }
2623   }
2624   return (non_escaped_allocs_worklist.length() > 0);
2625 }
2626 
2627 // Add all references to JavaObject node by walking over all uses.
2628 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
2629   int new_edges = 0;
2630   if (populate_worklist) {
2631     // Populate _worklist by uses of jobj's uses.
2632     for (UseIterator i(jobj); i.has_next(); i.next()) {
2633       PointsToNode* use = i.get();
2634       if (use->is_Arraycopy()) {
2635         continue;
2636       }
2637       add_uses_to_worklist(use);
2638       if (use->is_Field() && use->as_Field()->is_oop()) {
2639         // Put on worklist all field's uses (loads) and
2640         // related field nodes (same base and offset).
2641         add_field_uses_to_worklist(use->as_Field());
2642       }
2643     }
2644   }
2645   for (int l = 0; l < _worklist.length(); l++) {
2646     PointsToNode* use = _worklist.at(l);
2647     if (PointsToNode::is_base_use(use)) {
2648       // Add reference from jobj to field and from field to jobj (field's base).
2649       use = PointsToNode::get_use_node(use)->as_Field();
2650       if (add_base(use->as_Field(), jobj)) {
2651         new_edges++;
2652       }
2653       continue;
2654     }
2655     assert(!use->is_JavaObject(), "sanity");
2656     if (use->is_Arraycopy()) {
2657       if (jobj == null_obj) { // null object does not have field edges
2658         continue;
2659       }
2660       // Added edge from Arraycopy node to arraycopy's source java object
2661       if (add_edge(use, jobj)) {
2662         jobj->set_arraycopy_src();
2663         new_edges++;
2664       }
2665       // and stop here.
2666       continue;
2667     }
2668     if (!add_edge(use, jobj)) {
2669       continue; // No new edge added, there was such edge already.
2670     }
2671     new_edges++;
2672     if (use->is_LocalVar()) {
2673       add_uses_to_worklist(use);
2674       if (use->arraycopy_dst()) {
2675         for (EdgeIterator i(use); i.has_next(); i.next()) {
2676           PointsToNode* e = i.get();
2677           if (e->is_Arraycopy()) {
2678             if (jobj == null_obj) { // null object does not have field edges
2679               continue;
2680             }
2681             // Add edge from arraycopy's destination java object to Arraycopy node.
2682             if (add_edge(jobj, e)) {
2683               new_edges++;
2684               jobj->set_arraycopy_dst();
2685             }
2686           }
2687         }
2688       }
2689     } else {
2690       // Added new edge to stored in field values.
2691       // Put on worklist all field's uses (loads) and
2692       // related field nodes (same base and offset).
2693       add_field_uses_to_worklist(use->as_Field());
2694     }
2695   }
2696   _worklist.clear();
2697   _in_worklist.reset();
2698   return new_edges;
2699 }
2700 
2701 // Put on worklist all related field nodes.
2702 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
2703   assert(field->is_oop(), "sanity");
2704   int offset = field->offset();
2705   add_uses_to_worklist(field);
2706   // Loop over all bases of this field and push on worklist Field nodes
2707   // with the same offset and base (since they may reference the same field).
2708   for (BaseIterator i(field); i.has_next(); i.next()) {
2709     PointsToNode* base = i.get();
2710     add_fields_to_worklist(field, base);
2711     // Check if the base was source object of arraycopy and go over arraycopy's
2712     // destination objects since values stored to a field of source object are
2713     // accessible by uses (loads) of fields of destination objects.
2714     if (base->arraycopy_src()) {
2715       for (UseIterator j(base); j.has_next(); j.next()) {
2716         PointsToNode* arycp = j.get();
2717         if (arycp->is_Arraycopy()) {
2718           for (UseIterator k(arycp); k.has_next(); k.next()) {
2719             PointsToNode* abase = k.get();
2720             if (abase->arraycopy_dst() && abase != base) {
2721               // Look for the same arraycopy reference.
2722               add_fields_to_worklist(field, abase);
2723             }
2724           }
2725         }
2726       }
2727     }
2728   }
2729 }
2730 
2731 // Put on worklist all related field nodes.
2732 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
2733   int offset = field->offset();
2734   if (base->is_LocalVar()) {
2735     for (UseIterator j(base); j.has_next(); j.next()) {
2736       PointsToNode* f = j.get();
2737       if (PointsToNode::is_base_use(f)) { // Field
2738         f = PointsToNode::get_use_node(f);
2739         if (f == field || !f->as_Field()->is_oop()) {
2740           continue;
2741         }
2742         int offs = f->as_Field()->offset();
2743         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
2744           add_to_worklist(f);
2745         }
2746       }
2747     }
2748   } else {
2749     assert(base->is_JavaObject(), "sanity");
2750     if (// Skip phantom_object since it is only used to indicate that
2751         // this field's content globally escapes.
2752         (base != phantom_obj) &&
2753         // null object node does not have fields.
2754         (base != null_obj)) {
2755       for (EdgeIterator i(base); i.has_next(); i.next()) {
2756         PointsToNode* f = i.get();
2757         // Skip arraycopy edge since store to destination object field
2758         // does not update value in source object field.
2759         if (f->is_Arraycopy()) {
2760           assert(base->arraycopy_dst(), "sanity");
2761           continue;
2762         }
2763         if (f == field || !f->as_Field()->is_oop()) {
2764           continue;
2765         }
2766         int offs = f->as_Field()->offset();
2767         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
2768           add_to_worklist(f);
2769         }
2770       }
2771     }
2772   }
2773 }
2774 
2775 // Find fields which have unknown value.
2776 int ConnectionGraph::find_field_value(FieldNode* field) {
2777   // Escaped fields should have init value already.
2778   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
2779   int new_edges = 0;
2780   for (BaseIterator i(field); i.has_next(); i.next()) {
2781     PointsToNode* base = i.get();
2782     if (base->is_JavaObject()) {
2783       // Skip Allocate's fields which will be processed later.
2784       if (base->ideal_node()->is_Allocate()) {
2785         return 0;
2786       }
2787       assert(base == null_obj, "only null ptr base expected here");
2788     }
2789   }
2790   if (add_edge(field, phantom_obj)) {
2791     // New edge was added
2792     new_edges++;
2793     add_field_uses_to_worklist(field);
2794   }
2795   return new_edges;
2796 }
2797 
2798 // Find fields initializing values for allocations.
2799 int ConnectionGraph::find_init_values_phantom(JavaObjectNode* pta) {
2800   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
2801   PointsToNode* init_val = phantom_obj;
2802   Node* alloc = pta->ideal_node();
2803 
2804   // Do nothing for Allocate nodes since its fields values are
2805   // "known" unless they are initialized by arraycopy/clone.
2806   if (alloc->is_Allocate() && !pta->arraycopy_dst()) {
2807     if (alloc->as_Allocate()->in(AllocateNode::InitValue) != nullptr) {
2808       // Non-flat inline type arrays are initialized with
2809       // an init value instead of null. Handle them here.
2810       init_val = ptnode_adr(alloc->as_Allocate()->in(AllocateNode::InitValue)->_idx);
2811       assert(init_val != nullptr, "init value should be registered");
2812     } else {
2813       return 0;
2814     }
2815   }
2816   // Non-escaped allocation returned from Java or runtime call has unknown values in fields.
2817   assert(pta->arraycopy_dst() || alloc->is_CallStaticJava() || init_val != phantom_obj, "sanity");
2818 #ifdef ASSERT
2819   if (alloc->is_CallStaticJava() && alloc->as_CallStaticJava()->method() == nullptr) {
2820     const char* name = alloc->as_CallStaticJava()->_name;
2821     assert(strncmp(name, "C2 Runtime multianewarray", 25) == 0 ||
2822            strncmp(name, "C2 Runtime load_unknown_inline", 30) == 0, "sanity");
2823   }
2824 #endif
2825   // Non-escaped allocation returned from Java or runtime call have unknown values in fields.
2826   int new_edges = 0;
2827   for (EdgeIterator i(pta); i.has_next(); i.next()) {
2828     PointsToNode* field = i.get();
2829     if (field->is_Field() && field->as_Field()->is_oop()) {
2830       if (add_edge(field, init_val)) {
2831         // New edge was added
2832         new_edges++;
2833         add_field_uses_to_worklist(field->as_Field());
2834       }
2835     }
2836   }
2837   return new_edges;
2838 }
2839 
2840 // Find fields initializing values for allocations.
2841 int ConnectionGraph::find_init_values_null(JavaObjectNode* pta, PhaseValues* phase) {
2842   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
2843   Node* alloc = pta->ideal_node();
2844   // Do nothing for Call nodes since its fields values are unknown.
2845   if (!alloc->is_Allocate() || alloc->as_Allocate()->in(AllocateNode::InitValue) != nullptr) {
2846     return 0;
2847   }
2848   InitializeNode* ini = alloc->as_Allocate()->initialization();
2849   bool visited_bottom_offset = false;
2850   GrowableArray<int> offsets_worklist;
2851   int new_edges = 0;
2852 
2853   // Check if an oop field's initializing value is recorded and add
2854   // a corresponding null if field's value if it is not recorded.
2855   // Connection Graph does not record a default initialization by null
2856   // captured by Initialize node.
2857   //
2858   for (EdgeIterator i(pta); i.has_next(); i.next()) {
2859     PointsToNode* field = i.get(); // Field (AddP)
2860     if (!field->is_Field() || !field->as_Field()->is_oop()) {
2861       continue; // Not oop field
2862     }
2863     int offset = field->as_Field()->offset();
2864     if (offset == Type::OffsetBot) {
2865       if (!visited_bottom_offset) {
2866         // OffsetBot is used to reference array's element,
2867         // always add reference to null to all Field nodes since we don't
2868         // known which element is referenced.
2869         if (add_edge(field, null_obj)) {
2870           // New edge was added
2871           new_edges++;
2872           add_field_uses_to_worklist(field->as_Field());
2873           visited_bottom_offset = true;
2874         }
2875       }
2876     } else {
2877       // Check only oop fields.
2878       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
2879       if (adr_type->isa_rawptr()) {
2880 #ifdef ASSERT
2881         // Raw pointers are used for initializing stores so skip it
2882         // since it should be recorded already
2883         Node* base = get_addp_base(field->ideal_node());
2884         assert(adr_type->isa_rawptr() && is_captured_store_address(field->ideal_node()), "unexpected pointer type");
2885 #endif
2886         continue;
2887       }
2888       if (!offsets_worklist.contains(offset)) {
2889         offsets_worklist.append(offset);
2890         Node* value = nullptr;
2891         if (ini != nullptr) {
2892           // StoreP::memory_type() == T_ADDRESS
2893           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
2894           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
2895           // Make sure initializing store has the same type as this AddP.
2896           // This AddP may reference non existing field because it is on a
2897           // dead branch of bimorphic call which is not eliminated yet.
2898           if (store != nullptr && store->is_Store() &&
2899               store->as_Store()->memory_type() == ft) {
2900             value = store->in(MemNode::ValueIn);
2901 #ifdef ASSERT
2902             if (VerifyConnectionGraph) {
2903               // Verify that AddP already points to all objects the value points to.
2904               PointsToNode* val = ptnode_adr(value->_idx);
2905               assert((val != nullptr), "should be processed already");
2906               PointsToNode* missed_obj = nullptr;
2907               if (val->is_JavaObject()) {
2908                 if (!field->points_to(val->as_JavaObject())) {
2909                   missed_obj = val;
2910                 }
2911               } else {
2912                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
2913                   tty->print_cr("----------init store has invalid value -----");
2914                   store->dump();
2915                   val->dump();
2916                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
2917                 }
2918                 for (EdgeIterator j(val); j.has_next(); j.next()) {
2919                   PointsToNode* obj = j.get();
2920                   if (obj->is_JavaObject()) {
2921                     if (!field->points_to(obj->as_JavaObject())) {
2922                       missed_obj = obj;
2923                       break;
2924                     }
2925                   }
2926                 }
2927               }
2928               if (missed_obj != nullptr) {
2929                 tty->print_cr("----------field---------------------------------");
2930                 field->dump();
2931                 tty->print_cr("----------missed reference to object------------");
2932                 missed_obj->dump();
2933                 tty->print_cr("----------object referenced by init store-------");
2934                 store->dump();
2935                 val->dump();
2936                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
2937               }
2938             }
2939 #endif
2940           } else {
2941             // There could be initializing stores which follow allocation.
2942             // For example, a volatile field store is not collected
2943             // by Initialize node.
2944             //
2945             // Need to check for dependent loads to separate such stores from
2946             // stores which follow loads. For now, add initial value null so
2947             // that compare pointers optimization works correctly.
2948           }
2949         }
2950         if (value == nullptr) {
2951           // A field's initializing value was not recorded. Add null.
2952           if (add_edge(field, null_obj)) {
2953             // New edge was added
2954             new_edges++;
2955             add_field_uses_to_worklist(field->as_Field());
2956           }
2957         }
2958       }
2959     }
2960   }
2961   return new_edges;
2962 }
2963 
2964 // Adjust scalar_replaceable state after Connection Graph is built.
2965 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj, Unique_Node_List &reducible_merges) {
2966   // A Phi 'x' is a _candidate_ to be reducible if 'can_reduce_phi(x)'
2967   // returns true. If one of the constraints in this method set 'jobj' to NSR
2968   // then the candidate Phi is discarded. If the Phi has another SR 'jobj' as
2969   // input, 'adjust_scalar_replaceable_state' will eventually be called with
2970   // that other object and the Phi will become a reducible Phi.
2971   // There could be multiple merges involving the same jobj.
2972   Unique_Node_List candidates;
2973 
2974   // Search for non-escaping objects which are not scalar replaceable
2975   // and mark them to propagate the state to referenced objects.
2976 
2977   for (UseIterator i(jobj); i.has_next(); i.next()) {
2978     PointsToNode* use = i.get();
2979     if (use->is_Arraycopy()) {
2980       continue;
2981     }
2982     if (use->is_Field()) {
2983       FieldNode* field = use->as_Field();
2984       assert(field->is_oop() && field->scalar_replaceable(), "sanity");
2985       // 1. An object is not scalar replaceable if the field into which it is
2986       // stored has unknown offset (stored into unknown element of an array).
2987       if (field->offset() == Type::OffsetBot) {
2988         set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored at unknown offset"));
2989         return;
2990       }
2991       for (BaseIterator i(field); i.has_next(); i.next()) {
2992         PointsToNode* base = i.get();
2993         // 2. An object is not scalar replaceable if the field into which it is
2994         // stored has multiple bases one of which is null.
2995         if ((base == null_obj) && (field->base_count() > 1)) {
2996           set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with potentially null base"));
2997           return;
2998         }
2999         // 2.5. An object is not scalar replaceable if the field into which it is
3000         // stored has NSR base.
3001         if (!base->scalar_replaceable()) {
3002           set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with NSR base"));
3003           return;
3004         }
3005       }
3006     }
3007     assert(use->is_Field() || use->is_LocalVar(), "sanity");
3008     // 3. An object is not scalar replaceable if it is merged with other objects
3009     // and we can't remove the merge
3010     for (EdgeIterator j(use); j.has_next(); j.next()) {
3011       PointsToNode* ptn = j.get();
3012       if (ptn->is_JavaObject() && ptn != jobj) {
3013         Node* use_n = use->ideal_node();
3014 
3015         // These other local vars may point to multiple objects through a Phi
3016         // In this case we skip them and see if we can reduce the Phi.
3017         if (use_n->is_CastPP() || use_n->is_CheckCastPP()) {
3018           use_n = use_n->in(1);
3019         }
3020 
3021         // If it's already a candidate or confirmed reducible merge we can skip verification
3022         if (candidates.member(use_n) || reducible_merges.member(use_n)) {
3023           continue;
3024         }
3025 
3026         if (use_n->is_Phi() && can_reduce_phi(use_n->as_Phi())) {
3027           candidates.push(use_n);
3028         } else {
3029           // Mark all objects as NSR if we can't remove the merge
3030           set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA trace_merged_message(ptn)));
3031           set_not_scalar_replaceable(ptn NOT_PRODUCT(COMMA trace_merged_message(jobj)));
3032         }
3033       }
3034     }
3035     if (!jobj->scalar_replaceable()) {
3036       return;
3037     }
3038   }
3039 
3040   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
3041     if (j.get()->is_Arraycopy()) {
3042       continue;
3043     }
3044 
3045     // Non-escaping object node should point only to field nodes.
3046     FieldNode* field = j.get()->as_Field();
3047     int offset = field->as_Field()->offset();
3048 
3049     // 4. An object is not scalar replaceable if it has a field with unknown
3050     // offset (array's element is accessed in loop).
3051     if (offset == Type::OffsetBot) {
3052       set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "has field with unknown offset"));
3053       return;
3054     }
3055     // 5. Currently an object is not scalar replaceable if a LoadStore node
3056     // access its field since the field value is unknown after it.
3057     //
3058     Node* n = field->ideal_node();
3059 
3060     // Test for an unsafe access that was parsed as maybe off heap
3061     // (with a CheckCastPP to raw memory).
3062     assert(n->is_AddP(), "expect an address computation");
3063     if (n->in(AddPNode::Base)->is_top() &&
3064         n->in(AddPNode::Address)->Opcode() == Op_CheckCastPP) {
3065       assert(n->in(AddPNode::Address)->bottom_type()->isa_rawptr(), "raw address so raw cast expected");
3066       assert(_igvn->type(n->in(AddPNode::Address)->in(1))->isa_oopptr(), "cast pattern at unsafe access expected");
3067       set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is used as base of mixed unsafe access"));
3068       return;
3069     }
3070 
3071     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3072       Node* u = n->fast_out(i);
3073       if (u->is_LoadStore() || (u->is_Mem() && u->as_Mem()->is_mismatched_access())) {
3074         set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is used in LoadStore or mismatched access"));
3075         return;
3076       }
3077     }
3078 
3079     // 6. Or the address may point to more then one object. This may produce
3080     // the false positive result (set not scalar replaceable)
3081     // since the flow-insensitive escape analysis can't separate
3082     // the case when stores overwrite the field's value from the case
3083     // when stores happened on different control branches.
3084     //
3085     // Note: it will disable scalar replacement in some cases:
3086     //
3087     //    Point p[] = new Point[1];
3088     //    p[0] = new Point(); // Will be not scalar replaced
3089     //
3090     // but it will save us from incorrect optimizations in next cases:
3091     //
3092     //    Point p[] = new Point[1];
3093     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
3094     //
3095     if (field->base_count() > 1 && candidates.size() == 0) {
3096       if (has_non_reducible_merge(field, reducible_merges)) {
3097         for (BaseIterator i(field); i.has_next(); i.next()) {
3098           PointsToNode* base = i.get();
3099           // Don't take into account LocalVar nodes which
3100           // may point to only one object which should be also
3101           // this field's base by now.
3102           if (base->is_JavaObject() && base != jobj) {
3103             // Mark all bases.
3104             set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "may point to more than one object"));
3105             set_not_scalar_replaceable(base NOT_PRODUCT(COMMA "may point to more than one object"));
3106           }
3107         }
3108 
3109         if (!jobj->scalar_replaceable()) {
3110           return;
3111         }
3112       }
3113     }
3114   }
3115 
3116   // The candidate is truly a reducible merge only if none of the other
3117   // constraints ruled it as NSR. There could be multiple merges involving the
3118   // same jobj.
3119   assert(jobj->scalar_replaceable(), "sanity");
3120   for (uint i = 0; i < candidates.size(); i++ ) {
3121     Node* candidate = candidates.at(i);
3122     reducible_merges.push(candidate);
3123   }
3124 }
3125 
3126 bool ConnectionGraph::has_non_reducible_merge(FieldNode* field, Unique_Node_List& reducible_merges) {
3127   for (BaseIterator i(field); i.has_next(); i.next()) {
3128     Node* base = i.get()->ideal_node();
3129     if (base->is_Phi() && !reducible_merges.member(base)) {
3130       return true;
3131     }
3132   }
3133   return false;
3134 }
3135 
3136 void ConnectionGraph::revisit_reducible_phi_status(JavaObjectNode* jobj, Unique_Node_List& reducible_merges) {
3137   assert(jobj != nullptr && !jobj->scalar_replaceable(), "jobj should be set as NSR before calling this function.");
3138 
3139   // Look for 'phis' that refer to 'jobj' as the last
3140   // remaining scalar replaceable input.
3141   uint reducible_merges_cnt = reducible_merges.size();
3142   for (uint i = 0; i < reducible_merges_cnt; i++) {
3143     Node* phi = reducible_merges.at(i);
3144 
3145     // This 'Phi' will be a 'good' if it still points to
3146     // at least one scalar replaceable object. Note that 'obj'
3147     // was/should be marked as NSR before calling this function.
3148     bool good_phi = false;
3149 
3150     for (uint j = 1; j < phi->req(); j++) {
3151       JavaObjectNode* phi_in_obj = unique_java_object(phi->in(j));
3152       if (phi_in_obj != nullptr && phi_in_obj->scalar_replaceable()) {
3153         good_phi = true;
3154         break;
3155       }
3156     }
3157 
3158     if (!good_phi) {
3159       NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Phi %d became non-reducible after node %d became NSR.", phi->_idx, jobj->ideal_node()->_idx);)
3160       reducible_merges.remove(i);
3161 
3162       // Decrement the index because the 'remove' call above actually
3163       // moves the last entry of the list to position 'i'.
3164       i--;
3165 
3166       reducible_merges_cnt--;
3167     }
3168   }
3169 }
3170 
3171 // Propagate NSR (Not scalar replaceable) state.
3172 void ConnectionGraph::find_scalar_replaceable_allocs(GrowableArray<JavaObjectNode*>& jobj_worklist, Unique_Node_List &reducible_merges) {
3173   int jobj_length = jobj_worklist.length();
3174   bool found_nsr_alloc = true;
3175   while (found_nsr_alloc) {
3176     found_nsr_alloc = false;
3177     for (int next = 0; next < jobj_length; ++next) {
3178       JavaObjectNode* jobj = jobj_worklist.at(next);
3179       for (UseIterator i(jobj); (jobj->scalar_replaceable() && i.has_next()); i.next()) {
3180         PointsToNode* use = i.get();
3181         if (use->is_Field()) {
3182           FieldNode* field = use->as_Field();
3183           assert(field->is_oop() && field->scalar_replaceable(), "sanity");
3184           assert(field->offset() != Type::OffsetBot, "sanity");
3185           for (BaseIterator i(field); i.has_next(); i.next()) {
3186             PointsToNode* base = i.get();
3187             // An object is not scalar replaceable if the field into which
3188             // it is stored has NSR base.
3189             if ((base != null_obj) && !base->scalar_replaceable()) {
3190               set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with NSR base"));
3191               // Any merge that had only 'jobj' as scalar-replaceable will now be non-reducible,
3192               // because there is no point in reducing a Phi that won't improve the number of SR
3193               // objects.
3194               revisit_reducible_phi_status(jobj, reducible_merges);
3195               found_nsr_alloc = true;
3196               break;
3197             }
3198           }
3199         }
3200       }
3201     }
3202   }
3203 }
3204 
3205 #ifdef ASSERT
3206 void ConnectionGraph::verify_connection_graph(
3207                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
3208                          GrowableArray<JavaObjectNode*>& non_escaped_allocs_worklist,
3209                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
3210                          GrowableArray<Node*>& addp_worklist) {
3211   // Verify that graph is complete - no new edges could be added.
3212   int java_objects_length = java_objects_worklist.length();
3213   int non_escaped_length  = non_escaped_allocs_worklist.length();
3214   int new_edges = 0;
3215   for (int next = 0; next < java_objects_length; ++next) {
3216     JavaObjectNode* ptn = java_objects_worklist.at(next);
3217     new_edges += add_java_object_edges(ptn, true);
3218   }
3219   assert(new_edges == 0, "graph was not complete");
3220   // Verify that escape state is final.
3221   int length = non_escaped_allocs_worklist.length();
3222   find_non_escaped_objects(ptnodes_worklist, non_escaped_allocs_worklist);
3223   assert((non_escaped_length == non_escaped_allocs_worklist.length()) &&
3224          (non_escaped_length == length) &&
3225          (_worklist.length() == 0), "escape state was not final");
3226 
3227   // Verify fields information.
3228   int addp_length = addp_worklist.length();
3229   for (int next = 0; next < addp_length; ++next ) {
3230     Node* n = addp_worklist.at(next);
3231     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
3232     if (field->is_oop()) {
3233       // Verify that field has all bases
3234       Node* base = get_addp_base(n);
3235       PointsToNode* ptn = ptnode_adr(base->_idx);
3236       if (ptn->is_JavaObject()) {
3237         assert(field->has_base(ptn->as_JavaObject()), "sanity");
3238       } else {
3239         assert(ptn->is_LocalVar(), "sanity");
3240         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
3241           PointsToNode* e = i.get();
3242           if (e->is_JavaObject()) {
3243             assert(field->has_base(e->as_JavaObject()), "sanity");
3244           }
3245         }
3246       }
3247       // Verify that all fields have initializing values.
3248       if (field->edge_count() == 0) {
3249         tty->print_cr("----------field does not have references----------");
3250         field->dump();
3251         for (BaseIterator i(field); i.has_next(); i.next()) {
3252           PointsToNode* base = i.get();
3253           tty->print_cr("----------field has next base---------------------");
3254           base->dump();
3255           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
3256             tty->print_cr("----------base has fields-------------------------");
3257             for (EdgeIterator j(base); j.has_next(); j.next()) {
3258               j.get()->dump();
3259             }
3260             tty->print_cr("----------base has references---------------------");
3261             for (UseIterator j(base); j.has_next(); j.next()) {
3262               j.get()->dump();
3263             }
3264           }
3265         }
3266         for (UseIterator i(field); i.has_next(); i.next()) {
3267           i.get()->dump();
3268         }
3269         assert(field->edge_count() > 0, "sanity");
3270       }
3271     }
3272   }
3273 }
3274 #endif
3275 
3276 // Optimize ideal graph.
3277 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
3278                                            GrowableArray<MemBarStoreStoreNode*>& storestore_worklist) {
3279   Compile* C = _compile;
3280   PhaseIterGVN* igvn = _igvn;
3281   if (EliminateLocks) {
3282     // Mark locks before changing ideal graph.
3283     int cnt = C->macro_count();
3284     for (int i = 0; i < cnt; i++) {
3285       Node *n = C->macro_node(i);
3286       if (n->is_AbstractLock()) { // Lock and Unlock nodes
3287         AbstractLockNode* alock = n->as_AbstractLock();
3288         if (!alock->is_non_esc_obj()) {
3289           const Type* obj_type = igvn->type(alock->obj_node());
3290           if (can_eliminate_lock(alock) && !obj_type->is_inlinetypeptr()) {
3291             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
3292             // The lock could be marked eliminated by lock coarsening
3293             // code during first IGVN before EA. Replace coarsened flag
3294             // to eliminate all associated locks/unlocks.
3295 #ifdef ASSERT
3296             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
3297 #endif
3298             alock->set_non_esc_obj();
3299           }
3300         }
3301       }
3302     }
3303   }
3304 
3305   if (OptimizePtrCompare) {
3306     for (int i = 0; i < ptr_cmp_worklist.length(); i++) {
3307       Node *n = ptr_cmp_worklist.at(i);
3308       assert(n->Opcode() == Op_CmpN || n->Opcode() == Op_CmpP, "must be");
3309       const TypeInt* tcmp = optimize_ptr_compare(n->in(1), n->in(2));
3310       if (tcmp->singleton()) {
3311         Node* cmp = igvn->makecon(tcmp);
3312 #ifndef PRODUCT
3313         if (PrintOptimizePtrCompare) {
3314           tty->print_cr("++++ Replaced: %d %s(%d,%d) --> %s", n->_idx, (n->Opcode() == Op_CmpP ? "CmpP" : "CmpN"), n->in(1)->_idx, n->in(2)->_idx, (tcmp == TypeInt::CC_EQ ? "EQ" : "NotEQ"));
3315           if (Verbose) {
3316             n->dump(1);
3317           }
3318         }
3319 #endif
3320         igvn->replace_node(n, cmp);
3321       }
3322     }
3323   }
3324 
3325   // For MemBarStoreStore nodes added in library_call.cpp, check
3326   // escape status of associated AllocateNode and optimize out
3327   // MemBarStoreStore node if the allocated object never escapes.
3328   for (int i = 0; i < storestore_worklist.length(); i++) {
3329     Node* storestore = storestore_worklist.at(i);
3330     Node* alloc = storestore->in(MemBarNode::Precedent)->in(0);
3331     if (alloc->is_Allocate() && not_global_escape(alloc)) {
3332       if (alloc->in(AllocateNode::InlineType) != nullptr) {
3333         // Non-escaping inline type buffer allocations don't require a membar
3334         storestore->as_MemBar()->remove(_igvn);
3335       } else {
3336         MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
3337         mb->init_req(TypeFunc::Memory,  storestore->in(TypeFunc::Memory));
3338         mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
3339         igvn->register_new_node_with_optimizer(mb);
3340         igvn->replace_node(storestore, mb);
3341       }
3342     }
3343   }
3344 }
3345 
3346 // Optimize objects compare.
3347 const TypeInt* ConnectionGraph::optimize_ptr_compare(Node* left, Node* right) {
3348   assert(OptimizePtrCompare, "sanity");
3349   const TypeInt* EQ = TypeInt::CC_EQ; // [0] == ZERO
3350   const TypeInt* NE = TypeInt::CC_GT; // [1] == ONE
3351   const TypeInt* UNKNOWN = TypeInt::CC;    // [-1, 0,1]
3352 
3353   PointsToNode* ptn1 = ptnode_adr(left->_idx);
3354   PointsToNode* ptn2 = ptnode_adr(right->_idx);
3355   JavaObjectNode* jobj1 = unique_java_object(left);
3356   JavaObjectNode* jobj2 = unique_java_object(right);
3357 
3358   // The use of this method during allocation merge reduction may cause 'left'
3359   // or 'right' be something (e.g., a Phi) that isn't in the connection graph or
3360   // that doesn't reference an unique java object.
3361   if (ptn1 == nullptr || ptn2 == nullptr ||
3362       jobj1 == nullptr || jobj2 == nullptr) {
3363     return UNKNOWN;
3364   }
3365 
3366   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
3367   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
3368 
3369   // Check simple cases first.
3370   if (jobj1 != nullptr) {
3371     if (jobj1->escape_state() == PointsToNode::NoEscape) {
3372       if (jobj1 == jobj2) {
3373         // Comparing the same not escaping object.
3374         return EQ;
3375       }
3376       Node* obj = jobj1->ideal_node();
3377       // Comparing not escaping allocation.
3378       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
3379           !ptn2->points_to(jobj1)) {
3380         return NE; // This includes nullness check.
3381       }
3382     }
3383   }
3384   if (jobj2 != nullptr) {
3385     if (jobj2->escape_state() == PointsToNode::NoEscape) {
3386       Node* obj = jobj2->ideal_node();
3387       // Comparing not escaping allocation.
3388       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
3389           !ptn1->points_to(jobj2)) {
3390         return NE; // This includes nullness check.
3391       }
3392     }
3393   }
3394   if (jobj1 != nullptr && jobj1 != phantom_obj &&
3395       jobj2 != nullptr && jobj2 != phantom_obj &&
3396       jobj1->ideal_node()->is_Con() &&
3397       jobj2->ideal_node()->is_Con()) {
3398     // Klass or String constants compare. Need to be careful with
3399     // compressed pointers - compare types of ConN and ConP instead of nodes.
3400     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
3401     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
3402     if (t1->make_ptr() == t2->make_ptr()) {
3403       return EQ;
3404     } else {
3405       return NE;
3406     }
3407   }
3408   if (ptn1->meet(ptn2)) {
3409     return UNKNOWN; // Sets are not disjoint
3410   }
3411 
3412   // Sets are disjoint.
3413   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
3414   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
3415   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
3416   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
3417   if ((set1_has_unknown_ptr && set2_has_null_ptr) ||
3418       (set2_has_unknown_ptr && set1_has_null_ptr)) {
3419     // Check nullness of unknown object.
3420     return UNKNOWN;
3421   }
3422 
3423   // Disjointness by itself is not sufficient since
3424   // alias analysis is not complete for escaped objects.
3425   // Disjoint sets are definitely unrelated only when
3426   // at least one set has only not escaping allocations.
3427   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
3428     if (ptn1->non_escaping_allocation()) {
3429       return NE;
3430     }
3431   }
3432   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
3433     if (ptn2->non_escaping_allocation()) {
3434       return NE;
3435     }
3436   }
3437   return UNKNOWN;
3438 }
3439 
3440 // Connection Graph construction functions.
3441 
3442 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
3443   PointsToNode* ptadr = _nodes.at(n->_idx);
3444   if (ptadr != nullptr) {
3445     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
3446     return;
3447   }
3448   Compile* C = _compile;
3449   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
3450   map_ideal_node(n, ptadr);
3451 }
3452 
3453 PointsToNode* ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
3454   PointsToNode* ptadr = _nodes.at(n->_idx);
3455   if (ptadr != nullptr) {
3456     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
3457     return ptadr;
3458   }
3459   Compile* C = _compile;
3460   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
3461   map_ideal_node(n, ptadr);
3462   return ptadr;
3463 }
3464 
3465 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
3466   PointsToNode* ptadr = _nodes.at(n->_idx);
3467   if (ptadr != nullptr) {
3468     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
3469     return;
3470   }
3471   bool unsafe = false;
3472   bool is_oop = is_oop_field(n, offset, &unsafe);
3473   if (unsafe) {
3474     es = PointsToNode::GlobalEscape;
3475   }
3476   Compile* C = _compile;
3477   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
3478   map_ideal_node(n, field);
3479 }
3480 
3481 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
3482                                     PointsToNode* src, PointsToNode* dst) {
3483   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
3484   assert((src != null_obj) && (dst != null_obj), "not for ConP null");
3485   PointsToNode* ptadr = _nodes.at(n->_idx);
3486   if (ptadr != nullptr) {
3487     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
3488     return;
3489   }
3490   Compile* C = _compile;
3491   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
3492   map_ideal_node(n, ptadr);
3493   // Add edge from arraycopy node to source object.
3494   (void)add_edge(ptadr, src);
3495   src->set_arraycopy_src();
3496   // Add edge from destination object to arraycopy node.
3497   (void)add_edge(dst, ptadr);
3498   dst->set_arraycopy_dst();
3499 }
3500 
3501 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
3502   const Type* adr_type = n->as_AddP()->bottom_type();
3503   int field_offset = adr_type->isa_aryptr() ? adr_type->isa_aryptr()->field_offset().get() : Type::OffsetBot;
3504   BasicType bt = T_INT;
3505   if (offset == Type::OffsetBot && field_offset == Type::OffsetBot) {
3506     // Check only oop fields.
3507     if (!adr_type->isa_aryptr() ||
3508         adr_type->isa_aryptr()->elem() == Type::BOTTOM ||
3509         adr_type->isa_aryptr()->elem()->make_oopptr() != nullptr) {
3510       // OffsetBot is used to reference array's element. Ignore first AddP.
3511       if (find_second_addp(n, n->in(AddPNode::Base)) == nullptr) {
3512         bt = T_OBJECT;
3513       }
3514     }
3515   } else if (offset != oopDesc::klass_offset_in_bytes()) {
3516     if (adr_type->isa_instptr()) {
3517       ciField* field = _compile->alias_type(adr_type->is_ptr())->field();
3518       if (field != nullptr) {
3519         bt = field->layout_type();
3520       } else {
3521         // Check for unsafe oop field access
3522         if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN) ||
3523             n->has_out_with(Op_GetAndSetP, Op_GetAndSetN, Op_CompareAndExchangeP, Op_CompareAndExchangeN) ||
3524             n->has_out_with(Op_CompareAndSwapP, Op_CompareAndSwapN, Op_WeakCompareAndSwapP, Op_WeakCompareAndSwapN) ||
3525             BarrierSet::barrier_set()->barrier_set_c2()->escape_has_out_with_unsafe_object(n)) {
3526           bt = T_OBJECT;
3527           (*unsafe) = true;
3528         }
3529       }
3530     } else if (adr_type->isa_aryptr()) {
3531       if (offset == arrayOopDesc::length_offset_in_bytes()) {
3532         // Ignore array length load.
3533       } else if (find_second_addp(n, n->in(AddPNode::Base)) != nullptr) {
3534         // Ignore first AddP.
3535       } else {
3536         const Type* elemtype = adr_type->is_aryptr()->elem();
3537         if (adr_type->is_aryptr()->is_flat() && field_offset != Type::OffsetBot) {
3538           ciInlineKlass* vk = elemtype->inline_klass();
3539           field_offset += vk->payload_offset();
3540           bt = vk->get_field_by_offset(field_offset, false)->layout_type();
3541         } else {
3542           bt = elemtype->array_element_basic_type();
3543         }
3544       }
3545     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
3546       // Allocation initialization, ThreadLocal field access, unsafe access
3547       if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN) ||
3548           n->has_out_with(Op_GetAndSetP, Op_GetAndSetN, Op_CompareAndExchangeP, Op_CompareAndExchangeN) ||
3549           n->has_out_with(Op_CompareAndSwapP, Op_CompareAndSwapN, Op_WeakCompareAndSwapP, Op_WeakCompareAndSwapN) ||
3550           BarrierSet::barrier_set()->barrier_set_c2()->escape_has_out_with_unsafe_object(n)) {
3551         bt = T_OBJECT;
3552       }
3553     }
3554   }
3555   // Note: T_NARROWOOP is not classed as a real reference type
3556   return (is_reference_type(bt) || bt == T_NARROWOOP);
3557 }
3558 
3559 // Returns unique pointed java object or null.
3560 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) const {
3561   // If the node was created after the escape computation we can't answer.
3562   uint idx = n->_idx;
3563   if (idx >= nodes_size()) {
3564     return nullptr;
3565   }
3566   PointsToNode* ptn = ptnode_adr(idx);
3567   if (ptn == nullptr) {
3568     return nullptr;
3569   }
3570   if (ptn->is_JavaObject()) {
3571     return ptn->as_JavaObject();
3572   }
3573   assert(ptn->is_LocalVar(), "sanity");
3574   // Check all java objects it points to.
3575   JavaObjectNode* jobj = nullptr;
3576   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
3577     PointsToNode* e = i.get();
3578     if (e->is_JavaObject()) {
3579       if (jobj == nullptr) {
3580         jobj = e->as_JavaObject();
3581       } else if (jobj != e) {
3582         return nullptr;
3583       }
3584     }
3585   }
3586   return jobj;
3587 }
3588 
3589 // Return true if this node points only to non-escaping allocations.
3590 bool PointsToNode::non_escaping_allocation() {
3591   if (is_JavaObject()) {
3592     Node* n = ideal_node();
3593     if (n->is_Allocate() || n->is_CallStaticJava()) {
3594       return (escape_state() == PointsToNode::NoEscape);
3595     } else {
3596       return false;
3597     }
3598   }
3599   assert(is_LocalVar(), "sanity");
3600   // Check all java objects it points to.
3601   for (EdgeIterator i(this); i.has_next(); i.next()) {
3602     PointsToNode* e = i.get();
3603     if (e->is_JavaObject()) {
3604       Node* n = e->ideal_node();
3605       if ((e->escape_state() != PointsToNode::NoEscape) ||
3606           !(n->is_Allocate() || n->is_CallStaticJava())) {
3607         return false;
3608       }
3609     }
3610   }
3611   return true;
3612 }
3613 
3614 // Return true if we know the node does not escape globally.
3615 bool ConnectionGraph::not_global_escape(Node *n) {
3616   assert(!_collecting, "should not call during graph construction");
3617   // If the node was created after the escape computation we can't answer.
3618   uint idx = n->_idx;
3619   if (idx >= nodes_size()) {
3620     return false;
3621   }
3622   PointsToNode* ptn = ptnode_adr(idx);
3623   if (ptn == nullptr) {
3624     return false; // not in congraph (e.g. ConI)
3625   }
3626   PointsToNode::EscapeState es = ptn->escape_state();
3627   // If we have already computed a value, return it.
3628   if (es >= PointsToNode::GlobalEscape) {
3629     return false;
3630   }
3631   if (ptn->is_JavaObject()) {
3632     return true; // (es < PointsToNode::GlobalEscape);
3633   }
3634   assert(ptn->is_LocalVar(), "sanity");
3635   // Check all java objects it points to.
3636   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
3637     if (i.get()->escape_state() >= PointsToNode::GlobalEscape) {
3638       return false;
3639     }
3640   }
3641   return true;
3642 }
3643 
3644 // Return true if locked object does not escape globally
3645 // and locked code region (identified by BoxLockNode) is balanced:
3646 // all compiled code paths have corresponding Lock/Unlock pairs.
3647 bool ConnectionGraph::can_eliminate_lock(AbstractLockNode* alock) {
3648   if (alock->is_balanced() && not_global_escape(alock->obj_node())) {
3649     if (EliminateNestedLocks) {
3650       // We can mark whole locking region as Local only when only
3651       // one object is used for locking.
3652       alock->box_node()->as_BoxLock()->set_local();
3653     }
3654     return true;
3655   }
3656   return false;
3657 }
3658 
3659 // Helper functions
3660 
3661 // Return true if this node points to specified node or nodes it points to.
3662 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
3663   if (is_JavaObject()) {
3664     return (this == ptn);
3665   }
3666   assert(is_LocalVar() || is_Field(), "sanity");
3667   for (EdgeIterator i(this); i.has_next(); i.next()) {
3668     if (i.get() == ptn) {
3669       return true;
3670     }
3671   }
3672   return false;
3673 }
3674 
3675 // Return true if one node points to an other.
3676 bool PointsToNode::meet(PointsToNode* ptn) {
3677   if (this == ptn) {
3678     return true;
3679   } else if (ptn->is_JavaObject()) {
3680     return this->points_to(ptn->as_JavaObject());
3681   } else if (this->is_JavaObject()) {
3682     return ptn->points_to(this->as_JavaObject());
3683   }
3684   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
3685   int ptn_count =  ptn->edge_count();
3686   for (EdgeIterator i(this); i.has_next(); i.next()) {
3687     PointsToNode* this_e = i.get();
3688     for (int j = 0; j < ptn_count; j++) {
3689       if (this_e == ptn->edge(j)) {
3690         return true;
3691       }
3692     }
3693   }
3694   return false;
3695 }
3696 
3697 #ifdef ASSERT
3698 // Return true if bases point to this java object.
3699 bool FieldNode::has_base(JavaObjectNode* jobj) const {
3700   for (BaseIterator i(this); i.has_next(); i.next()) {
3701     if (i.get() == jobj) {
3702       return true;
3703     }
3704   }
3705   return false;
3706 }
3707 #endif
3708 
3709 bool ConnectionGraph::is_captured_store_address(Node* addp) {
3710   // Handle simple case first.
3711   assert(_igvn->type(addp)->isa_oopptr() == nullptr, "should be raw access");
3712   if (addp->in(AddPNode::Address)->is_Proj() && addp->in(AddPNode::Address)->in(0)->is_Allocate()) {
3713     return true;
3714   } else if (addp->in(AddPNode::Address)->is_Phi()) {
3715     for (DUIterator_Fast imax, i = addp->fast_outs(imax); i < imax; i++) {
3716       Node* addp_use = addp->fast_out(i);
3717       if (addp_use->is_Store()) {
3718         for (DUIterator_Fast jmax, j = addp_use->fast_outs(jmax); j < jmax; j++) {
3719           if (addp_use->fast_out(j)->is_Initialize()) {
3720             return true;
3721           }
3722         }
3723       }
3724     }
3725   }
3726   return false;
3727 }
3728 
3729 int ConnectionGraph::address_offset(Node* adr, PhaseValues* phase) {
3730   const Type *adr_type = phase->type(adr);
3731   if (adr->is_AddP() && adr_type->isa_oopptr() == nullptr && is_captured_store_address(adr)) {
3732     // We are computing a raw address for a store captured by an Initialize
3733     // compute an appropriate address type. AddP cases #3 and #5 (see below).
3734     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
3735     assert(offs != Type::OffsetBot ||
3736            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
3737            "offset must be a constant or it is initialization of array");
3738     return offs;
3739   }
3740   return adr_type->is_ptr()->flat_offset();
3741 }
3742 
3743 Node* ConnectionGraph::get_addp_base(Node *addp) {
3744   assert(addp->is_AddP(), "must be AddP");
3745   //
3746   // AddP cases for Base and Address inputs:
3747   // case #1. Direct object's field reference:
3748   //     Allocate
3749   //       |
3750   //     Proj #5 ( oop result )
3751   //       |
3752   //     CheckCastPP (cast to instance type)
3753   //      | |
3754   //     AddP  ( base == address )
3755   //
3756   // case #2. Indirect object's field reference:
3757   //      Phi
3758   //       |
3759   //     CastPP (cast to instance type)
3760   //      | |
3761   //     AddP  ( base == address )
3762   //
3763   // case #3. Raw object's field reference for Initialize node:
3764   //      Allocate
3765   //        |
3766   //      Proj #5 ( oop result )
3767   //  top   |
3768   //     \  |
3769   //     AddP  ( base == top )
3770   //
3771   // case #4. Array's element reference:
3772   //   {CheckCastPP | CastPP}
3773   //     |  | |
3774   //     |  AddP ( array's element offset )
3775   //     |  |
3776   //     AddP ( array's offset )
3777   //
3778   // case #5. Raw object's field reference for arraycopy stub call:
3779   //          The inline_native_clone() case when the arraycopy stub is called
3780   //          after the allocation before Initialize and CheckCastPP nodes.
3781   //      Allocate
3782   //        |
3783   //      Proj #5 ( oop result )
3784   //       | |
3785   //       AddP  ( base == address )
3786   //
3787   // case #6. Constant Pool, ThreadLocal, CastX2P or
3788   //          Raw object's field reference:
3789   //      {ConP, ThreadLocal, CastX2P, raw Load}
3790   //  top   |
3791   //     \  |
3792   //     AddP  ( base == top )
3793   //
3794   // case #7. Klass's field reference.
3795   //      LoadKlass
3796   //       | |
3797   //       AddP  ( base == address )
3798   //
3799   // case #8. narrow Klass's field reference.
3800   //      LoadNKlass
3801   //       |
3802   //      DecodeN
3803   //       | |
3804   //       AddP  ( base == address )
3805   //
3806   // case #9. Mixed unsafe access
3807   //    {instance}
3808   //        |
3809   //      CheckCastPP (raw)
3810   //  top   |
3811   //     \  |
3812   //     AddP  ( base == top )
3813   //
3814   Node *base = addp->in(AddPNode::Base);
3815   if (base->uncast()->is_top()) { // The AddP case #3 and #6 and #9.
3816     base = addp->in(AddPNode::Address);
3817     while (base->is_AddP()) {
3818       // Case #6 (unsafe access) may have several chained AddP nodes.
3819       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
3820       base = base->in(AddPNode::Address);
3821     }
3822     if (base->Opcode() == Op_CheckCastPP &&
3823         base->bottom_type()->isa_rawptr() &&
3824         _igvn->type(base->in(1))->isa_oopptr()) {
3825       base = base->in(1); // Case #9
3826     } else {
3827       Node* uncast_base = base->uncast();
3828       int opcode = uncast_base->Opcode();
3829       assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
3830              opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
3831              (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != nullptr)) ||
3832              is_captured_store_address(addp), "sanity");
3833     }
3834   }
3835   return base;
3836 }
3837 
3838 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
3839   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
3840   Node* addp2 = addp->raw_out(0);
3841   if (addp->outcnt() == 1 && addp2->is_AddP() &&
3842       addp2->in(AddPNode::Base) == n &&
3843       addp2->in(AddPNode::Address) == addp) {
3844     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
3845     //
3846     // Find array's offset to push it on worklist first and
3847     // as result process an array's element offset first (pushed second)
3848     // to avoid CastPP for the array's offset.
3849     // Otherwise the inserted CastPP (LocalVar) will point to what
3850     // the AddP (Field) points to. Which would be wrong since
3851     // the algorithm expects the CastPP has the same point as
3852     // as AddP's base CheckCastPP (LocalVar).
3853     //
3854     //    ArrayAllocation
3855     //     |
3856     //    CheckCastPP
3857     //     |
3858     //    memProj (from ArrayAllocation CheckCastPP)
3859     //     |  ||
3860     //     |  ||   Int (element index)
3861     //     |  ||    |   ConI (log(element size))
3862     //     |  ||    |   /
3863     //     |  ||   LShift
3864     //     |  ||  /
3865     //     |  AddP (array's element offset)
3866     //     |  |
3867     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
3868     //     | / /
3869     //     AddP (array's offset)
3870     //      |
3871     //     Load/Store (memory operation on array's element)
3872     //
3873     return addp2;
3874   }
3875   return nullptr;
3876 }
3877 
3878 //
3879 // Adjust the type and inputs of an AddP which computes the
3880 // address of a field of an instance
3881 //
3882 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
3883   PhaseGVN* igvn = _igvn;
3884   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
3885   assert(base_t != nullptr && base_t->is_known_instance(), "expecting instance oopptr");
3886   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
3887   if (t == nullptr) {
3888     // We are computing a raw address for a store captured by an Initialize
3889     // compute an appropriate address type (cases #3 and #5).
3890     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
3891     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
3892     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
3893     assert(offs != Type::OffsetBot, "offset must be a constant");
3894     if (base_t->isa_aryptr() != nullptr) {
3895       // In the case of a flat inline type array, each field has its
3896       // own slice so we need to extract the field being accessed from
3897       // the address computation
3898       t = base_t->isa_aryptr()->add_field_offset_and_offset(offs)->is_oopptr();
3899     } else {
3900       t = base_t->add_offset(offs)->is_oopptr();
3901     }
3902   }
3903   int inst_id = base_t->instance_id();
3904   assert(!t->is_known_instance() || t->instance_id() == inst_id,
3905                              "old type must be non-instance or match new type");
3906 
3907   // The type 't' could be subclass of 'base_t'.
3908   // As result t->offset() could be large then base_t's size and it will
3909   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
3910   // constructor verifies correctness of the offset.
3911   //
3912   // It could happened on subclass's branch (from the type profiling
3913   // inlining) which was not eliminated during parsing since the exactness
3914   // of the allocation type was not propagated to the subclass type check.
3915   //
3916   // Or the type 't' could be not related to 'base_t' at all.
3917   // It could happen when CHA type is different from MDO type on a dead path
3918   // (for example, from instanceof check) which is not collapsed during parsing.
3919   //
3920   // Do nothing for such AddP node and don't process its users since
3921   // this code branch will go away.
3922   //
3923   if (!t->is_known_instance() &&
3924       !base_t->maybe_java_subtype_of(t)) {
3925      return false; // bail out
3926   }
3927   const TypePtr* tinst = base_t->add_offset(t->offset());
3928   if (tinst->isa_aryptr() && t->isa_aryptr()) {
3929     // In the case of a flat inline type array, each field has its
3930     // own slice so we need to keep track of the field being accessed.
3931     tinst = tinst->is_aryptr()->with_field_offset(t->is_aryptr()->field_offset().get());
3932     // Keep array properties (not flat/null-free)
3933     tinst = tinst->is_aryptr()->update_properties(t->is_aryptr());
3934     if (tinst == nullptr) {
3935       return false; // Skip dead path with inconsistent properties
3936     }
3937   }
3938 
3939   // Do NOT remove the next line: ensure a new alias index is allocated
3940   // for the instance type. Note: C++ will not remove it since the call
3941   // has side effect.
3942   int alias_idx = _compile->get_alias_index(tinst);
3943   igvn->set_type(addp, tinst);
3944   // record the allocation in the node map
3945   set_map(addp, get_map(base->_idx));
3946   // Set addp's Base and Address to 'base'.
3947   Node *abase = addp->in(AddPNode::Base);
3948   Node *adr   = addp->in(AddPNode::Address);
3949   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
3950       adr->in(0)->_idx == (uint)inst_id) {
3951     // Skip AddP cases #3 and #5.
3952   } else {
3953     assert(!abase->is_top(), "sanity"); // AddP case #3
3954     if (abase != base) {
3955       igvn->hash_delete(addp);
3956       addp->set_req(AddPNode::Base, base);
3957       if (abase == adr) {
3958         addp->set_req(AddPNode::Address, base);
3959       } else {
3960         // AddP case #4 (adr is array's element offset AddP node)
3961 #ifdef ASSERT
3962         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
3963         assert(adr->is_AddP() && atype != nullptr &&
3964                atype->instance_id() == inst_id, "array's element offset should be processed first");
3965 #endif
3966       }
3967       igvn->hash_insert(addp);
3968     }
3969   }
3970   // Put on IGVN worklist since at least addp's type was changed above.
3971   record_for_optimizer(addp);
3972   return true;
3973 }
3974 
3975 //
3976 // Create a new version of orig_phi if necessary. Returns either the newly
3977 // created phi or an existing phi.  Sets create_new to indicate whether a new
3978 // phi was created.  Cache the last newly created phi in the node map.
3979 //
3980 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
3981   Compile *C = _compile;
3982   PhaseGVN* igvn = _igvn;
3983   new_created = false;
3984   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
3985   // nothing to do if orig_phi is bottom memory or matches alias_idx
3986   if (phi_alias_idx == alias_idx) {
3987     return orig_phi;
3988   }
3989   // Have we recently created a Phi for this alias index?
3990   PhiNode *result = get_map_phi(orig_phi->_idx);
3991   if (result != nullptr && C->get_alias_index(result->adr_type()) == alias_idx) {
3992     return result;
3993   }
3994   // Previous check may fail when the same wide memory Phi was split into Phis
3995   // for different memory slices. Search all Phis for this region.
3996   if (result != nullptr) {
3997     Node* region = orig_phi->in(0);
3998     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
3999       Node* phi = region->fast_out(i);
4000       if (phi->is_Phi() &&
4001           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
4002         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
4003         return phi->as_Phi();
4004       }
4005     }
4006   }
4007   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
4008     if (C->do_escape_analysis() == true && !C->failing()) {
4009       // Retry compilation without escape analysis.
4010       // If this is the first failure, the sentinel string will "stick"
4011       // to the Compile object, and the C2Compiler will see it and retry.
4012       C->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4013     }
4014     return nullptr;
4015   }
4016   orig_phi_worklist.append_if_missing(orig_phi);
4017   const TypePtr *atype = C->get_adr_type(alias_idx);
4018   result = PhiNode::make(orig_phi->in(0), nullptr, Type::MEMORY, atype);
4019   C->copy_node_notes_to(result, orig_phi);
4020   igvn->set_type(result, result->bottom_type());
4021   record_for_optimizer(result);
4022   set_map(orig_phi, result);
4023   new_created = true;
4024   return result;
4025 }
4026 
4027 //
4028 // Return a new version of Memory Phi "orig_phi" with the inputs having the
4029 // specified alias index.
4030 //
4031 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *> &orig_phi_worklist, uint rec_depth) {
4032   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
4033   Compile *C = _compile;
4034   PhaseGVN* igvn = _igvn;
4035   bool new_phi_created;
4036   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
4037   if (!new_phi_created) {
4038     return result;
4039   }
4040   GrowableArray<PhiNode *>  phi_list;
4041   GrowableArray<uint>  cur_input;
4042   PhiNode *phi = orig_phi;
4043   uint idx = 1;
4044   bool finished = false;
4045   while(!finished) {
4046     while (idx < phi->req()) {
4047       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist, rec_depth + 1);
4048       if (mem != nullptr && mem->is_Phi()) {
4049         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
4050         if (new_phi_created) {
4051           // found an phi for which we created a new split, push current one on worklist and begin
4052           // processing new one
4053           phi_list.push(phi);
4054           cur_input.push(idx);
4055           phi = mem->as_Phi();
4056           result = newphi;
4057           idx = 1;
4058           continue;
4059         } else {
4060           mem = newphi;
4061         }
4062       }
4063       if (C->failing()) {
4064         return nullptr;
4065       }
4066       result->set_req(idx++, mem);
4067     }
4068 #ifdef ASSERT
4069     // verify that the new Phi has an input for each input of the original
4070     assert( phi->req() == result->req(), "must have same number of inputs.");
4071     assert( result->in(0) != nullptr && result->in(0) == phi->in(0), "regions must match");
4072 #endif
4073     // Check if all new phi's inputs have specified alias index.
4074     // Otherwise use old phi.
4075     for (uint i = 1; i < phi->req(); i++) {
4076       Node* in = result->in(i);
4077       assert((phi->in(i) == nullptr) == (in == nullptr), "inputs must correspond.");
4078     }
4079     // we have finished processing a Phi, see if there are any more to do
4080     finished = (phi_list.length() == 0 );
4081     if (!finished) {
4082       phi = phi_list.pop();
4083       idx = cur_input.pop();
4084       PhiNode *prev_result = get_map_phi(phi->_idx);
4085       prev_result->set_req(idx++, result);
4086       result = prev_result;
4087     }
4088   }
4089   return result;
4090 }
4091 
4092 //
4093 // The next methods are derived from methods in MemNode.
4094 //
4095 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
4096   Node *mem = mmem;
4097   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
4098   // means an array I have not precisely typed yet.  Do not do any
4099   // alias stuff with it any time soon.
4100   if (toop->base() != Type::AnyPtr &&
4101       !(toop->isa_instptr() &&
4102         toop->is_instptr()->instance_klass()->is_java_lang_Object() &&
4103         toop->offset() == Type::OffsetBot)) {
4104     mem = mmem->memory_at(alias_idx);
4105     // Update input if it is progress over what we have now
4106   }
4107   return mem;
4108 }
4109 
4110 //
4111 // Move memory users to their memory slices.
4112 //
4113 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
4114   Compile* C = _compile;
4115   PhaseGVN* igvn = _igvn;
4116   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
4117   assert(tp != nullptr, "ptr type");
4118   int alias_idx = C->get_alias_index(tp);
4119   int general_idx = C->get_general_index(alias_idx);
4120 
4121   // Move users first
4122   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4123     Node* use = n->fast_out(i);
4124     if (use->is_MergeMem()) {
4125       MergeMemNode* mmem = use->as_MergeMem();
4126       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
4127       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
4128         continue; // Nothing to do
4129       }
4130       // Replace previous general reference to mem node.
4131       uint orig_uniq = C->unique();
4132       Node* m = find_inst_mem(n, general_idx, orig_phis);
4133       assert(orig_uniq == C->unique(), "no new nodes");
4134       mmem->set_memory_at(general_idx, m);
4135       --imax;
4136       --i;
4137     } else if (use->is_MemBar()) {
4138       assert(!use->is_Initialize(), "initializing stores should not be moved");
4139       if (use->req() > MemBarNode::Precedent &&
4140           use->in(MemBarNode::Precedent) == n) {
4141         // Don't move related membars.
4142         record_for_optimizer(use);
4143         continue;
4144       }
4145       tp = use->as_MemBar()->adr_type()->isa_ptr();
4146       if ((tp != nullptr && C->get_alias_index(tp) == alias_idx) ||
4147           alias_idx == general_idx) {
4148         continue; // Nothing to do
4149       }
4150       // Move to general memory slice.
4151       uint orig_uniq = C->unique();
4152       Node* m = find_inst_mem(n, general_idx, orig_phis);
4153       assert(orig_uniq == C->unique(), "no new nodes");
4154       igvn->hash_delete(use);
4155       imax -= use->replace_edge(n, m, igvn);
4156       igvn->hash_insert(use);
4157       record_for_optimizer(use);
4158       --i;
4159 #ifdef ASSERT
4160     } else if (use->is_Mem()) {
4161       // Memory nodes should have new memory input.
4162       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
4163       assert(tp != nullptr, "ptr type");
4164       int idx = C->get_alias_index(tp);
4165       assert(get_map(use->_idx) != nullptr || idx == alias_idx,
4166              "Following memory nodes should have new memory input or be on the same memory slice");
4167     } else if (use->is_Phi()) {
4168       // Phi nodes should be split and moved already.
4169       tp = use->as_Phi()->adr_type()->isa_ptr();
4170       assert(tp != nullptr, "ptr type");
4171       int idx = C->get_alias_index(tp);
4172       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
4173     } else {
4174       use->dump();
4175       assert(false, "should not be here");
4176 #endif
4177     }
4178   }
4179 }
4180 
4181 //
4182 // Search memory chain of "mem" to find a MemNode whose address
4183 // is the specified alias index.
4184 //
4185 #define FIND_INST_MEM_RECURSION_DEPTH_LIMIT 1000
4186 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis, uint rec_depth) {
4187   if (rec_depth > FIND_INST_MEM_RECURSION_DEPTH_LIMIT) {
4188     _compile->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4189     return nullptr;
4190   }
4191   if (orig_mem == nullptr) {
4192     return orig_mem;
4193   }
4194   Compile* C = _compile;
4195   PhaseGVN* igvn = _igvn;
4196   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
4197   bool is_instance = (toop != nullptr) && toop->is_known_instance();
4198   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
4199   Node *prev = nullptr;
4200   Node *result = orig_mem;
4201   while (prev != result) {
4202     prev = result;
4203     if (result == start_mem) {
4204       break;  // hit one of our sentinels
4205     }
4206     if (result->is_Mem()) {
4207       const Type *at = igvn->type(result->in(MemNode::Address));
4208       if (at == Type::TOP) {
4209         break; // Dead
4210       }
4211       assert (at->isa_ptr() != nullptr, "pointer type required.");
4212       int idx = C->get_alias_index(at->is_ptr());
4213       if (idx == alias_idx) {
4214         break; // Found
4215       }
4216       if (!is_instance && (at->isa_oopptr() == nullptr ||
4217                            !at->is_oopptr()->is_known_instance())) {
4218         break; // Do not skip store to general memory slice.
4219       }
4220       result = result->in(MemNode::Memory);
4221     }
4222     if (!is_instance) {
4223       continue;  // don't search further for non-instance types
4224     }
4225     // skip over a call which does not affect this memory slice
4226     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
4227       Node *proj_in = result->in(0);
4228       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
4229         break;  // hit one of our sentinels
4230       } else if (proj_in->is_Call()) {
4231         // ArrayCopy node processed here as well
4232         CallNode *call = proj_in->as_Call();
4233         if (!call->may_modify(toop, igvn)) {
4234           result = call->in(TypeFunc::Memory);
4235         }
4236       } else if (proj_in->is_Initialize()) {
4237         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
4238         // Stop if this is the initialization for the object instance which
4239         // which contains this memory slice, otherwise skip over it.
4240         if (alloc == nullptr || alloc->_idx != (uint)toop->instance_id()) {
4241           result = proj_in->in(TypeFunc::Memory);
4242         }
4243       } else if (proj_in->is_MemBar()) {
4244         // Check if there is an array copy for a clone
4245         // Step over GC barrier when ReduceInitialCardMarks is disabled
4246         BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
4247         Node* control_proj_ac = bs->step_over_gc_barrier(proj_in->in(0));
4248 
4249         if (control_proj_ac->is_Proj() && control_proj_ac->in(0)->is_ArrayCopy()) {
4250           // Stop if it is a clone
4251           ArrayCopyNode* ac = control_proj_ac->in(0)->as_ArrayCopy();
4252           if (ac->may_modify(toop, igvn)) {
4253             break;
4254           }
4255         }
4256         result = proj_in->in(TypeFunc::Memory);
4257       }
4258     } else if (result->is_MergeMem()) {
4259       MergeMemNode *mmem = result->as_MergeMem();
4260       result = step_through_mergemem(mmem, alias_idx, toop);
4261       if (result == mmem->base_memory()) {
4262         // Didn't find instance memory, search through general slice recursively.
4263         result = mmem->memory_at(C->get_general_index(alias_idx));
4264         result = find_inst_mem(result, alias_idx, orig_phis, rec_depth + 1);
4265         if (C->failing()) {
4266           return nullptr;
4267         }
4268         mmem->set_memory_at(alias_idx, result);
4269       }
4270     } else if (result->is_Phi() &&
4271                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
4272       Node *un = result->as_Phi()->unique_input(igvn);
4273       if (un != nullptr) {
4274         orig_phis.append_if_missing(result->as_Phi());
4275         result = un;
4276       } else {
4277         break;
4278       }
4279     } else if (result->is_ClearArray()) {
4280       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
4281         // Can not bypass initialization of the instance
4282         // we are looking for.
4283         break;
4284       }
4285       // Otherwise skip it (the call updated 'result' value).
4286     } else if (result->Opcode() == Op_SCMemProj) {
4287       Node* mem = result->in(0);
4288       Node* adr = nullptr;
4289       if (mem->is_LoadStore()) {
4290         adr = mem->in(MemNode::Address);
4291       } else {
4292         assert(mem->Opcode() == Op_EncodeISOArray ||
4293                mem->Opcode() == Op_StrCompressedCopy, "sanity");
4294         adr = mem->in(3); // Memory edge corresponds to destination array
4295       }
4296       const Type *at = igvn->type(adr);
4297       if (at != Type::TOP) {
4298         assert(at->isa_ptr() != nullptr, "pointer type required.");
4299         int idx = C->get_alias_index(at->is_ptr());
4300         if (idx == alias_idx) {
4301           // Assert in debug mode
4302           assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
4303           break; // In product mode return SCMemProj node
4304         }
4305       }
4306       result = mem->in(MemNode::Memory);
4307     } else if (result->Opcode() == Op_StrInflatedCopy) {
4308       Node* adr = result->in(3); // Memory edge corresponds to destination array
4309       const Type *at = igvn->type(adr);
4310       if (at != Type::TOP) {
4311         assert(at->isa_ptr() != nullptr, "pointer type required.");
4312         int idx = C->get_alias_index(at->is_ptr());
4313         if (idx == alias_idx) {
4314           // Assert in debug mode
4315           assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
4316           break; // In product mode return SCMemProj node
4317         }
4318       }
4319       result = result->in(MemNode::Memory);
4320     }
4321   }
4322   if (result->is_Phi()) {
4323     PhiNode *mphi = result->as_Phi();
4324     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
4325     const TypePtr *t = mphi->adr_type();
4326     if (!is_instance) {
4327       // Push all non-instance Phis on the orig_phis worklist to update inputs
4328       // during Phase 4 if needed.
4329       orig_phis.append_if_missing(mphi);
4330     } else if (C->get_alias_index(t) != alias_idx) {
4331       // Create a new Phi with the specified alias index type.
4332       result = split_memory_phi(mphi, alias_idx, orig_phis, rec_depth + 1);
4333     }
4334   }
4335   // the result is either MemNode, PhiNode, InitializeNode.
4336   return result;
4337 }
4338 
4339 //
4340 //  Convert the types of non-escaped object to instance types where possible,
4341 //  propagate the new type information through the graph, and update memory
4342 //  edges and MergeMem inputs to reflect the new type.
4343 //
4344 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
4345 //  The processing is done in 4 phases:
4346 //
4347 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
4348 //            types for the CheckCastPP for allocations where possible.
4349 //            Propagate the new types through users as follows:
4350 //               casts and Phi:  push users on alloc_worklist
4351 //               AddP:  cast Base and Address inputs to the instance type
4352 //                      push any AddP users on alloc_worklist and push any memnode
4353 //                      users onto memnode_worklist.
4354 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
4355 //            search the Memory chain for a store with the appropriate type
4356 //            address type.  If a Phi is found, create a new version with
4357 //            the appropriate memory slices from each of the Phi inputs.
4358 //            For stores, process the users as follows:
4359 //               MemNode:  push on memnode_worklist
4360 //               MergeMem: push on mergemem_worklist
4361 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
4362 //            moving the first node encountered of each  instance type to the
4363 //            the input corresponding to its alias index.
4364 //            appropriate memory slice.
4365 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
4366 //
4367 // In the following example, the CheckCastPP nodes are the cast of allocation
4368 // results and the allocation of node 29 is non-escaped and eligible to be an
4369 // instance type.
4370 //
4371 // We start with:
4372 //
4373 //     7 Parm #memory
4374 //    10  ConI  "12"
4375 //    19  CheckCastPP   "Foo"
4376 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
4377 //    29  CheckCastPP   "Foo"
4378 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
4379 //
4380 //    40  StoreP  25   7  20   ... alias_index=4
4381 //    50  StoreP  35  40  30   ... alias_index=4
4382 //    60  StoreP  45  50  20   ... alias_index=4
4383 //    70  LoadP    _  60  30   ... alias_index=4
4384 //    80  Phi     75  50  60   Memory alias_index=4
4385 //    90  LoadP    _  80  30   ... alias_index=4
4386 //   100  LoadP    _  80  20   ... alias_index=4
4387 //
4388 //
4389 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
4390 // and creating a new alias index for node 30.  This gives:
4391 //
4392 //     7 Parm #memory
4393 //    10  ConI  "12"
4394 //    19  CheckCastPP   "Foo"
4395 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
4396 //    29  CheckCastPP   "Foo"  iid=24
4397 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
4398 //
4399 //    40  StoreP  25   7  20   ... alias_index=4
4400 //    50  StoreP  35  40  30   ... alias_index=6
4401 //    60  StoreP  45  50  20   ... alias_index=4
4402 //    70  LoadP    _  60  30   ... alias_index=6
4403 //    80  Phi     75  50  60   Memory alias_index=4
4404 //    90  LoadP    _  80  30   ... alias_index=6
4405 //   100  LoadP    _  80  20   ... alias_index=4
4406 //
4407 // In phase 2, new memory inputs are computed for the loads and stores,
4408 // And a new version of the phi is created.  In phase 4, the inputs to
4409 // node 80 are updated and then the memory nodes are updated with the
4410 // values computed in phase 2.  This results in:
4411 //
4412 //     7 Parm #memory
4413 //    10  ConI  "12"
4414 //    19  CheckCastPP   "Foo"
4415 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
4416 //    29  CheckCastPP   "Foo"  iid=24
4417 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
4418 //
4419 //    40  StoreP  25  7   20   ... alias_index=4
4420 //    50  StoreP  35  7   30   ... alias_index=6
4421 //    60  StoreP  45  40  20   ... alias_index=4
4422 //    70  LoadP    _  50  30   ... alias_index=6
4423 //    80  Phi     75  40  60   Memory alias_index=4
4424 //   120  Phi     75  50  50   Memory alias_index=6
4425 //    90  LoadP    _ 120  30   ... alias_index=6
4426 //   100  LoadP    _  80  20   ... alias_index=4
4427 //
4428 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist,
4429                                          GrowableArray<ArrayCopyNode*> &arraycopy_worklist,
4430                                          GrowableArray<MergeMemNode*> &mergemem_worklist,
4431                                          Unique_Node_List &reducible_merges) {
4432   DEBUG_ONLY(Unique_Node_List reduced_merges;)
4433   GrowableArray<Node *>  memnode_worklist;
4434   GrowableArray<PhiNode *>  orig_phis;
4435   PhaseIterGVN  *igvn = _igvn;
4436   uint new_index_start = (uint) _compile->num_alias_types();
4437   VectorSet visited;
4438   ideal_nodes.clear(); // Reset for use with set_map/get_map.
4439   uint unique_old = _compile->unique();
4440 
4441   //  Phase 1:  Process possible allocations from alloc_worklist.
4442   //  Create instance types for the CheckCastPP for allocations where possible.
4443   //
4444   // (Note: don't forget to change the order of the second AddP node on
4445   //  the alloc_worklist if the order of the worklist processing is changed,
4446   //  see the comment in find_second_addp().)
4447   //
4448   while (alloc_worklist.length() != 0) {
4449     Node *n = alloc_worklist.pop();
4450     uint ni = n->_idx;
4451     if (n->is_Call()) {
4452       CallNode *alloc = n->as_Call();
4453       // copy escape information to call node
4454       PointsToNode* ptn = ptnode_adr(alloc->_idx);
4455       PointsToNode::EscapeState es = ptn->escape_state();
4456       // We have an allocation or call which returns a Java object,
4457       // see if it is non-escaped.
4458       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable()) {
4459         continue;
4460       }
4461       // Find CheckCastPP for the allocate or for the return value of a call
4462       n = alloc->result_cast();
4463       if (n == nullptr) {            // No uses except Initialize node
4464         if (alloc->is_Allocate()) {
4465           // Set the scalar_replaceable flag for allocation
4466           // so it could be eliminated if it has no uses.
4467           alloc->as_Allocate()->_is_scalar_replaceable = true;
4468         }
4469         continue;
4470       }
4471       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
4472         // we could reach here for allocate case if one init is associated with many allocs.
4473         if (alloc->is_Allocate()) {
4474           alloc->as_Allocate()->_is_scalar_replaceable = false;
4475         }
4476         continue;
4477       }
4478 
4479       // The inline code for Object.clone() casts the allocation result to
4480       // java.lang.Object and then to the actual type of the allocated
4481       // object. Detect this case and use the second cast.
4482       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
4483       // the allocation result is cast to java.lang.Object and then
4484       // to the actual Array type.
4485       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
4486           && (alloc->is_AllocateArray() ||
4487               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeInstKlassPtr::OBJECT)) {
4488         Node *cast2 = nullptr;
4489         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4490           Node *use = n->fast_out(i);
4491           if (use->is_CheckCastPP()) {
4492             cast2 = use;
4493             break;
4494           }
4495         }
4496         if (cast2 != nullptr) {
4497           n = cast2;
4498         } else {
4499           // Non-scalar replaceable if the allocation type is unknown statically
4500           // (reflection allocation), the object can't be restored during
4501           // deoptimization without precise type.
4502           continue;
4503         }
4504       }
4505 
4506       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
4507       if (t == nullptr) {
4508         continue;  // not a TypeOopPtr
4509       }
4510       if (!t->klass_is_exact()) {
4511         continue; // not an unique type
4512       }
4513       if (alloc->is_Allocate()) {
4514         // Set the scalar_replaceable flag for allocation
4515         // so it could be eliminated.
4516         alloc->as_Allocate()->_is_scalar_replaceable = true;
4517       }
4518       set_escape_state(ptnode_adr(n->_idx), es NOT_PRODUCT(COMMA trace_propagate_message(ptn))); // CheckCastPP escape state
4519       // in order for an object to be scalar-replaceable, it must be:
4520       //   - a direct allocation (not a call returning an object)
4521       //   - non-escaping
4522       //   - eligible to be a unique type
4523       //   - not determined to be ineligible by escape analysis
4524       set_map(alloc, n);
4525       set_map(n, alloc);
4526       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
4527       igvn->hash_delete(n);
4528       igvn->set_type(n,  tinst);
4529       n->raise_bottom_type(tinst);
4530       igvn->hash_insert(n);
4531       record_for_optimizer(n);
4532       // Allocate an alias index for the header fields. Accesses to
4533       // the header emitted during macro expansion wouldn't have
4534       // correct memory state otherwise.
4535       _compile->get_alias_index(tinst->add_offset(oopDesc::mark_offset_in_bytes()));
4536       _compile->get_alias_index(tinst->add_offset(oopDesc::klass_offset_in_bytes()));
4537       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
4538 
4539         // First, put on the worklist all Field edges from Connection Graph
4540         // which is more accurate than putting immediate users from Ideal Graph.
4541         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
4542           PointsToNode* tgt = e.get();
4543           if (tgt->is_Arraycopy()) {
4544             continue;
4545           }
4546           Node* use = tgt->ideal_node();
4547           assert(tgt->is_Field() && use->is_AddP(),
4548                  "only AddP nodes are Field edges in CG");
4549           if (use->outcnt() > 0) { // Don't process dead nodes
4550             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
4551             if (addp2 != nullptr) {
4552               assert(alloc->is_AllocateArray(),"array allocation was expected");
4553               alloc_worklist.append_if_missing(addp2);
4554             }
4555             alloc_worklist.append_if_missing(use);
4556           }
4557         }
4558 
4559         // An allocation may have an Initialize which has raw stores. Scan
4560         // the users of the raw allocation result and push AddP users
4561         // on alloc_worklist.
4562         Node *raw_result = alloc->proj_out_or_null(TypeFunc::Parms);
4563         assert (raw_result != nullptr, "must have an allocation result");
4564         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
4565           Node *use = raw_result->fast_out(i);
4566           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
4567             Node* addp2 = find_second_addp(use, raw_result);
4568             if (addp2 != nullptr) {
4569               assert(alloc->is_AllocateArray(),"array allocation was expected");
4570               alloc_worklist.append_if_missing(addp2);
4571             }
4572             alloc_worklist.append_if_missing(use);
4573           } else if (use->is_MemBar()) {
4574             memnode_worklist.append_if_missing(use);
4575           }
4576         }
4577       }
4578     } else if (n->is_AddP()) {
4579       if (has_reducible_merge_base(n->as_AddP(), reducible_merges)) {
4580         // This AddP will go away when we reduce the Phi
4581         continue;
4582       }
4583       Node* addp_base = get_addp_base(n);
4584       JavaObjectNode* jobj = unique_java_object(addp_base);
4585       if (jobj == nullptr || jobj == phantom_obj) {
4586 #ifdef ASSERT
4587         ptnode_adr(get_addp_base(n)->_idx)->dump();
4588         ptnode_adr(n->_idx)->dump();
4589         assert(jobj != nullptr && jobj != phantom_obj, "escaped allocation");
4590 #endif
4591         _compile->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4592         return;
4593       }
4594       Node *base = get_map(jobj->idx());  // CheckCastPP node
4595       if (!split_AddP(n, base)) continue; // wrong type from dead path
4596     } else if (n->is_Phi() ||
4597                n->is_CheckCastPP() ||
4598                n->is_EncodeP() ||
4599                n->is_DecodeN() ||
4600                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
4601       if (visited.test_set(n->_idx)) {
4602         assert(n->is_Phi(), "loops only through Phi's");
4603         continue;  // already processed
4604       }
4605       // Reducible Phi's will be removed from the graph after split_unique_types
4606       // finishes. For now we just try to split out the SR inputs of the merge.
4607       Node* parent = n->in(1);
4608       if (reducible_merges.member(n)) {
4609         reduce_phi(n->as_Phi(), alloc_worklist, memnode_worklist);
4610 #ifdef ASSERT
4611         if (VerifyReduceAllocationMerges) {
4612           reduced_merges.push(n);
4613         }
4614 #endif
4615         continue;
4616       } else if (reducible_merges.member(parent)) {
4617         // 'n' is an user of a reducible merge (a Phi). It will be simplified as
4618         // part of reduce_merge.
4619         continue;
4620       }
4621       JavaObjectNode* jobj = unique_java_object(n);
4622       if (jobj == nullptr || jobj == phantom_obj) {
4623 #ifdef ASSERT
4624         ptnode_adr(n->_idx)->dump();
4625         assert(jobj != nullptr && jobj != phantom_obj, "escaped allocation");
4626 #endif
4627         _compile->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4628         return;
4629       } else {
4630         Node *val = get_map(jobj->idx());   // CheckCastPP node
4631         TypeNode *tn = n->as_Type();
4632         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
4633         assert(tinst != nullptr && tinst->is_known_instance() &&
4634                tinst->instance_id() == jobj->idx() , "instance type expected.");
4635 
4636         const Type *tn_type = igvn->type(tn);
4637         const TypeOopPtr *tn_t;
4638         if (tn_type->isa_narrowoop()) {
4639           tn_t = tn_type->make_ptr()->isa_oopptr();
4640         } else {
4641           tn_t = tn_type->isa_oopptr();
4642         }
4643         if (tn_t != nullptr && tinst->maybe_java_subtype_of(tn_t)) {
4644           if (tn_t->isa_aryptr()) {
4645             // Keep array properties (not flat/null-free)
4646             tinst = tinst->is_aryptr()->update_properties(tn_t->is_aryptr());
4647             if (tinst == nullptr) {
4648               continue; // Skip dead path with inconsistent properties
4649             }
4650           }
4651           if (tn_type->isa_narrowoop()) {
4652             tn_type = tinst->make_narrowoop();
4653           } else {
4654             tn_type = tinst;
4655           }
4656           igvn->hash_delete(tn);
4657           igvn->set_type(tn, tn_type);
4658           tn->set_type(tn_type);
4659           igvn->hash_insert(tn);
4660           record_for_optimizer(n);
4661         } else {
4662           assert(tn_type == TypePtr::NULL_PTR ||
4663                  (tn_t != nullptr && !tinst->maybe_java_subtype_of(tn_t)),
4664                  "unexpected type");
4665           continue; // Skip dead path with different type
4666         }
4667       }
4668     } else {
4669       debug_only(n->dump();)
4670       assert(false, "EA: unexpected node");
4671       continue;
4672     }
4673     // push allocation's users on appropriate worklist
4674     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4675       Node *use = n->fast_out(i);
4676       if (use->is_Mem() && use->in(MemNode::Address) == n) {
4677         // Load/store to instance's field
4678         memnode_worklist.append_if_missing(use);
4679       } else if (use->is_MemBar()) {
4680         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
4681           memnode_worklist.append_if_missing(use);
4682         }
4683       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
4684         Node* addp2 = find_second_addp(use, n);
4685         if (addp2 != nullptr) {
4686           alloc_worklist.append_if_missing(addp2);
4687         }
4688         alloc_worklist.append_if_missing(use);
4689       } else if (use->is_Phi() ||
4690                  use->is_CheckCastPP() ||
4691                  use->is_EncodeNarrowPtr() ||
4692                  use->is_DecodeNarrowPtr() ||
4693                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
4694         alloc_worklist.append_if_missing(use);
4695 #ifdef ASSERT
4696       } else if (use->is_Mem()) {
4697         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
4698       } else if (use->is_MergeMem()) {
4699         assert(mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
4700       } else if (use->is_SafePoint()) {
4701         // Look for MergeMem nodes for calls which reference unique allocation
4702         // (through CheckCastPP nodes) even for debug info.
4703         Node* m = use->in(TypeFunc::Memory);
4704         if (m->is_MergeMem()) {
4705           assert(mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
4706         }
4707       } else if (use->Opcode() == Op_EncodeISOArray) {
4708         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
4709           // EncodeISOArray overwrites destination array
4710           memnode_worklist.append_if_missing(use);
4711         }
4712       } else if (use->Opcode() == Op_Return) {
4713         // Allocation is referenced by field of returned inline type
4714         assert(_compile->tf()->returns_inline_type_as_fields(), "EA: unexpected reference by ReturnNode");
4715       } else {
4716         uint op = use->Opcode();
4717         if ((op == Op_StrCompressedCopy || op == Op_StrInflatedCopy) &&
4718             (use->in(MemNode::Memory) == n)) {
4719           // They overwrite memory edge corresponding to destination array,
4720           memnode_worklist.append_if_missing(use);
4721         } else if (!(op == Op_CmpP || op == Op_Conv2B ||
4722               op == Op_CastP2X ||
4723               op == Op_FastLock || op == Op_AryEq ||
4724               op == Op_StrComp || op == Op_CountPositives ||
4725               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
4726               op == Op_StrEquals || op == Op_VectorizedHashCode ||
4727               op == Op_StrIndexOf || op == Op_StrIndexOfChar ||
4728               op == Op_SubTypeCheck || op == Op_InlineType || op == Op_FlatArrayCheck ||
4729               op == Op_ReinterpretS2HF ||
4730               BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(use))) {
4731           n->dump();
4732           use->dump();
4733           assert(false, "EA: missing allocation reference path");
4734         }
4735 #endif
4736       }
4737     }
4738 
4739   }
4740 
4741 #ifdef ASSERT
4742   if (VerifyReduceAllocationMerges) {
4743     for (uint i = 0; i < reducible_merges.size(); i++) {
4744       Node* phi = reducible_merges.at(i);
4745 
4746       if (!reduced_merges.member(phi)) {
4747         phi->dump(2);
4748         phi->dump(-2);
4749         assert(false, "This reducible merge wasn't reduced.");
4750       }
4751 
4752       // At this point reducible Phis shouldn't have AddP users anymore; only SafePoints or Casts.
4753       for (DUIterator_Fast jmax, j = phi->fast_outs(jmax); j < jmax; j++) {
4754         Node* use = phi->fast_out(j);
4755         if (!use->is_SafePoint() && !use->is_CastPP()) {
4756           phi->dump(2);
4757           phi->dump(-2);
4758           assert(false, "Unexpected user of reducible Phi -> %d:%s:%d", use->_idx, use->Name(), use->outcnt());
4759         }
4760       }
4761     }
4762   }
4763 #endif
4764 
4765   // Go over all ArrayCopy nodes and if one of the inputs has a unique
4766   // type, record it in the ArrayCopy node so we know what memory this
4767   // node uses/modified.
4768   for (int next = 0; next < arraycopy_worklist.length(); next++) {
4769     ArrayCopyNode* ac = arraycopy_worklist.at(next);
4770     Node* dest = ac->in(ArrayCopyNode::Dest);
4771     if (dest->is_AddP()) {
4772       dest = get_addp_base(dest);
4773     }
4774     JavaObjectNode* jobj = unique_java_object(dest);
4775     if (jobj != nullptr) {
4776       Node *base = get_map(jobj->idx());
4777       if (base != nullptr) {
4778         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
4779         ac->_dest_type = base_t;
4780       }
4781     }
4782     Node* src = ac->in(ArrayCopyNode::Src);
4783     if (src->is_AddP()) {
4784       src = get_addp_base(src);
4785     }
4786     jobj = unique_java_object(src);
4787     if (jobj != nullptr) {
4788       Node* base = get_map(jobj->idx());
4789       if (base != nullptr) {
4790         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
4791         ac->_src_type = base_t;
4792       }
4793     }
4794   }
4795 
4796   // New alias types were created in split_AddP().
4797   uint new_index_end = (uint) _compile->num_alias_types();
4798 
4799   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
4800   //            compute new values for Memory inputs  (the Memory inputs are not
4801   //            actually updated until phase 4.)
4802   if (memnode_worklist.length() == 0)
4803     return;  // nothing to do
4804   while (memnode_worklist.length() != 0) {
4805     Node *n = memnode_worklist.pop();
4806     if (visited.test_set(n->_idx)) {
4807       continue;
4808     }
4809     if (n->is_Phi() || n->is_ClearArray()) {
4810       // we don't need to do anything, but the users must be pushed
4811     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
4812       // we don't need to do anything, but the users must be pushed
4813       n = n->as_MemBar()->proj_out_or_null(TypeFunc::Memory);
4814       if (n == nullptr) {
4815         continue;
4816       }
4817     } else if (n->is_CallLeaf()) {
4818       // Runtime calls with narrow memory input (no MergeMem node)
4819       // get the memory projection
4820       n = n->as_Call()->proj_out_or_null(TypeFunc::Memory);
4821       if (n == nullptr) {
4822         continue;
4823       }
4824     } else if (n->Opcode() == Op_StrInflatedCopy) {
4825       // Check direct uses of StrInflatedCopy.
4826       // It is memory type Node - no special SCMemProj node.
4827     } else if (n->Opcode() == Op_StrCompressedCopy ||
4828                n->Opcode() == Op_EncodeISOArray) {
4829       // get the memory projection
4830       n = n->find_out_with(Op_SCMemProj);
4831       assert(n != nullptr && n->Opcode() == Op_SCMemProj, "memory projection required");
4832     } else if (n->is_CallLeaf() && n->as_CallLeaf()->_name != nullptr &&
4833                strcmp(n->as_CallLeaf()->_name, "store_unknown_inline") == 0) {
4834       n = n->as_CallLeaf()->proj_out(TypeFunc::Memory);
4835     } else {
4836 #ifdef ASSERT
4837       if (!n->is_Mem()) {
4838         n->dump();
4839       }
4840       assert(n->is_Mem(), "memory node required.");
4841 #endif
4842       Node *addr = n->in(MemNode::Address);
4843       const Type *addr_t = igvn->type(addr);
4844       if (addr_t == Type::TOP) {
4845         continue;
4846       }
4847       assert (addr_t->isa_ptr() != nullptr, "pointer type required.");
4848       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
4849       assert ((uint)alias_idx < new_index_end, "wrong alias index");
4850       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
4851       if (_compile->failing()) {
4852         return;
4853       }
4854       if (mem != n->in(MemNode::Memory)) {
4855         // We delay the memory edge update since we need old one in
4856         // MergeMem code below when instances memory slices are separated.
4857         set_map(n, mem);
4858       }
4859       if (n->is_Load()) {
4860         continue;  // don't push users
4861       } else if (n->is_LoadStore()) {
4862         // get the memory projection
4863         n = n->find_out_with(Op_SCMemProj);
4864         assert(n != nullptr && n->Opcode() == Op_SCMemProj, "memory projection required");
4865       }
4866     }
4867     // push user on appropriate worklist
4868     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4869       Node *use = n->fast_out(i);
4870       if (use->is_Phi() || use->is_ClearArray()) {
4871         memnode_worklist.append_if_missing(use);
4872       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
4873         memnode_worklist.append_if_missing(use);
4874       } else if (use->is_MemBar() || use->is_CallLeaf()) {
4875         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
4876           memnode_worklist.append_if_missing(use);
4877         }
4878 #ifdef ASSERT
4879       } else if (use->is_Mem()) {
4880         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
4881       } else if (use->is_MergeMem()) {
4882         assert(mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
4883       } else if (use->Opcode() == Op_EncodeISOArray) {
4884         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
4885           // EncodeISOArray overwrites destination array
4886           memnode_worklist.append_if_missing(use);
4887         }
4888       } else if (use->is_CallLeaf() && use->as_CallLeaf()->_name != nullptr &&
4889                  strcmp(use->as_CallLeaf()->_name, "store_unknown_inline") == 0) {
4890         // store_unknown_inline overwrites destination array
4891         memnode_worklist.append_if_missing(use);
4892       } else {
4893         uint op = use->Opcode();
4894         if ((use->in(MemNode::Memory) == n) &&
4895             (op == Op_StrCompressedCopy || op == Op_StrInflatedCopy)) {
4896           // They overwrite memory edge corresponding to destination array,
4897           memnode_worklist.append_if_missing(use);
4898         } else if (!(BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(use) ||
4899               op == Op_AryEq || op == Op_StrComp || op == Op_CountPositives ||
4900               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy || op == Op_VectorizedHashCode ||
4901               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar || op == Op_FlatArrayCheck)) {
4902           n->dump();
4903           use->dump();
4904           assert(false, "EA: missing memory path");
4905         }
4906 #endif
4907       }
4908     }
4909   }
4910 
4911   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
4912   //            Walk each memory slice moving the first node encountered of each
4913   //            instance type to the input corresponding to its alias index.
4914   uint length = mergemem_worklist.length();
4915   for( uint next = 0; next < length; ++next ) {
4916     MergeMemNode* nmm = mergemem_worklist.at(next);
4917     assert(!visited.test_set(nmm->_idx), "should not be visited before");
4918     // Note: we don't want to use MergeMemStream here because we only want to
4919     // scan inputs which exist at the start, not ones we add during processing.
4920     // Note 2: MergeMem may already contains instance memory slices added
4921     // during find_inst_mem() call when memory nodes were processed above.
4922     igvn->hash_delete(nmm);
4923     uint nslices = MIN2(nmm->req(), new_index_start);
4924     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
4925       Node* mem = nmm->in(i);
4926       Node* cur = nullptr;
4927       if (mem == nullptr || mem->is_top()) {
4928         continue;
4929       }
4930       // First, update mergemem by moving memory nodes to corresponding slices
4931       // if their type became more precise since this mergemem was created.
4932       while (mem->is_Mem()) {
4933         const Type *at = igvn->type(mem->in(MemNode::Address));
4934         if (at != Type::TOP) {
4935           assert (at->isa_ptr() != nullptr, "pointer type required.");
4936           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
4937           if (idx == i) {
4938             if (cur == nullptr) {
4939               cur = mem;
4940             }
4941           } else {
4942             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
4943               nmm->set_memory_at(idx, mem);
4944             }
4945           }
4946         }
4947         mem = mem->in(MemNode::Memory);
4948       }
4949       nmm->set_memory_at(i, (cur != nullptr) ? cur : mem);
4950       // Find any instance of the current type if we haven't encountered
4951       // already a memory slice of the instance along the memory chain.
4952       for (uint ni = new_index_start; ni < new_index_end; ni++) {
4953         if((uint)_compile->get_general_index(ni) == i) {
4954           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
4955           if (nmm->is_empty_memory(m)) {
4956             Node* result = find_inst_mem(mem, ni, orig_phis);
4957             if (_compile->failing()) {
4958               return;
4959             }
4960             nmm->set_memory_at(ni, result);
4961           }
4962         }
4963       }
4964     }
4965     // Find the rest of instances values
4966     for (uint ni = new_index_start; ni < new_index_end; ni++) {
4967       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
4968       Node* result = step_through_mergemem(nmm, ni, tinst);
4969       if (result == nmm->base_memory()) {
4970         // Didn't find instance memory, search through general slice recursively.
4971         result = nmm->memory_at(_compile->get_general_index(ni));
4972         result = find_inst_mem(result, ni, orig_phis);
4973         if (_compile->failing()) {
4974           return;
4975         }
4976         nmm->set_memory_at(ni, result);
4977       }
4978     }
4979 
4980     // If we have crossed the 3/4 point of max node limit it's too risky
4981     // to continue with EA/SR because we might hit the max node limit.
4982     if (_compile->live_nodes() >= _compile->max_node_limit() * 0.75) {
4983       if (_compile->do_reduce_allocation_merges()) {
4984         _compile->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
4985       } else if (_invocation > 0) {
4986         _compile->record_failure(C2Compiler::retry_no_iterative_escape_analysis());
4987       } else {
4988         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
4989       }
4990       return;
4991     }
4992 
4993     igvn->hash_insert(nmm);
4994     record_for_optimizer(nmm);
4995   }
4996 
4997   //  Phase 4:  Update the inputs of non-instance memory Phis and
4998   //            the Memory input of memnodes
4999   // First update the inputs of any non-instance Phi's from
5000   // which we split out an instance Phi.  Note we don't have
5001   // to recursively process Phi's encountered on the input memory
5002   // chains as is done in split_memory_phi() since they will
5003   // also be processed here.
5004   for (int j = 0; j < orig_phis.length(); j++) {
5005     PhiNode *phi = orig_phis.at(j);
5006     int alias_idx = _compile->get_alias_index(phi->adr_type());
5007     igvn->hash_delete(phi);
5008     for (uint i = 1; i < phi->req(); i++) {
5009       Node *mem = phi->in(i);
5010       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
5011       if (_compile->failing()) {
5012         return;
5013       }
5014       if (mem != new_mem) {
5015         phi->set_req(i, new_mem);
5016       }
5017     }
5018     igvn->hash_insert(phi);
5019     record_for_optimizer(phi);
5020   }
5021 
5022   // Update the memory inputs of MemNodes with the value we computed
5023   // in Phase 2 and move stores memory users to corresponding memory slices.
5024   // Disable memory split verification code until the fix for 6984348.
5025   // Currently it produces false negative results since it does not cover all cases.
5026 #if 0 // ifdef ASSERT
5027   visited.Reset();
5028   Node_Stack old_mems(arena, _compile->unique() >> 2);
5029 #endif
5030   for (uint i = 0; i < ideal_nodes.size(); i++) {
5031     Node*    n = ideal_nodes.at(i);
5032     Node* nmem = get_map(n->_idx);
5033     assert(nmem != nullptr, "sanity");
5034     if (n->is_Mem()) {
5035 #if 0 // ifdef ASSERT
5036       Node* old_mem = n->in(MemNode::Memory);
5037       if (!visited.test_set(old_mem->_idx)) {
5038         old_mems.push(old_mem, old_mem->outcnt());
5039       }
5040 #endif
5041       assert(n->in(MemNode::Memory) != nmem, "sanity");
5042       if (!n->is_Load()) {
5043         // Move memory users of a store first.
5044         move_inst_mem(n, orig_phis);
5045       }
5046       // Now update memory input
5047       igvn->hash_delete(n);
5048       n->set_req(MemNode::Memory, nmem);
5049       igvn->hash_insert(n);
5050       record_for_optimizer(n);
5051     } else {
5052       assert(n->is_Allocate() || n->is_CheckCastPP() ||
5053              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
5054     }
5055   }
5056 #if 0 // ifdef ASSERT
5057   // Verify that memory was split correctly
5058   while (old_mems.is_nonempty()) {
5059     Node* old_mem = old_mems.node();
5060     uint  old_cnt = old_mems.index();
5061     old_mems.pop();
5062     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
5063   }
5064 #endif
5065 }
5066 
5067 #ifndef PRODUCT
5068 int ConnectionGraph::_no_escape_counter = 0;
5069 int ConnectionGraph::_arg_escape_counter = 0;
5070 int ConnectionGraph::_global_escape_counter = 0;
5071 
5072 static const char *node_type_names[] = {
5073   "UnknownType",
5074   "JavaObject",
5075   "LocalVar",
5076   "Field",
5077   "Arraycopy"
5078 };
5079 
5080 static const char *esc_names[] = {
5081   "UnknownEscape",
5082   "NoEscape",
5083   "ArgEscape",
5084   "GlobalEscape"
5085 };
5086 
5087 void PointsToNode::dump_header(bool print_state, outputStream* out) const {
5088   NodeType nt = node_type();
5089   out->print("%s(%d) ", node_type_names[(int) nt], _pidx);
5090   if (print_state) {
5091     EscapeState es = escape_state();
5092     EscapeState fields_es = fields_escape_state();
5093     out->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
5094     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable()) {
5095       out->print("NSR ");
5096     }
5097   }
5098 }
5099 
5100 void PointsToNode::dump(bool print_state, outputStream* out, bool newline) const {
5101   dump_header(print_state, out);
5102   if (is_Field()) {
5103     FieldNode* f = (FieldNode*)this;
5104     if (f->is_oop()) {
5105       out->print("oop ");
5106     }
5107     if (f->offset() > 0) {
5108       out->print("+%d ", f->offset());
5109     }
5110     out->print("(");
5111     for (BaseIterator i(f); i.has_next(); i.next()) {
5112       PointsToNode* b = i.get();
5113       out->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
5114     }
5115     out->print(" )");
5116   }
5117   out->print("[");
5118   for (EdgeIterator i(this); i.has_next(); i.next()) {
5119     PointsToNode* e = i.get();
5120     out->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
5121   }
5122   out->print(" [");
5123   for (UseIterator i(this); i.has_next(); i.next()) {
5124     PointsToNode* u = i.get();
5125     bool is_base = false;
5126     if (PointsToNode::is_base_use(u)) {
5127       is_base = true;
5128       u = PointsToNode::get_use_node(u)->as_Field();
5129     }
5130     out->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
5131   }
5132   out->print(" ]]  ");
5133   if (_node == nullptr) {
5134     out->print("<null>%s", newline ? "\n" : "");
5135   } else {
5136     _node->dump(newline ? "\n" : "", false, out);
5137   }
5138 }
5139 
5140 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
5141   bool first = true;
5142   int ptnodes_length = ptnodes_worklist.length();
5143   for (int i = 0; i < ptnodes_length; i++) {
5144     PointsToNode *ptn = ptnodes_worklist.at(i);
5145     if (ptn == nullptr || !ptn->is_JavaObject()) {
5146       continue;
5147     }
5148     PointsToNode::EscapeState es = ptn->escape_state();
5149     if ((es != PointsToNode::NoEscape) && !Verbose) {
5150       continue;
5151     }
5152     Node* n = ptn->ideal_node();
5153     if (n->is_Allocate() || (n->is_CallStaticJava() &&
5154                              n->as_CallStaticJava()->is_boxing_method())) {
5155       if (first) {
5156         tty->cr();
5157         tty->print("======== Connection graph for ");
5158         _compile->method()->print_short_name();
5159         tty->cr();
5160         tty->print_cr("invocation #%d: %d iterations and %f sec to build connection graph with %d nodes and worklist size %d",
5161                       _invocation, _build_iterations, _build_time, nodes_size(), ptnodes_worklist.length());
5162         tty->cr();
5163         first = false;
5164       }
5165       ptn->dump();
5166       // Print all locals and fields which reference this allocation
5167       for (UseIterator j(ptn); j.has_next(); j.next()) {
5168         PointsToNode* use = j.get();
5169         if (use->is_LocalVar()) {
5170           use->dump(Verbose);
5171         } else if (Verbose) {
5172           use->dump();
5173         }
5174       }
5175       tty->cr();
5176     }
5177   }
5178 }
5179 
5180 void ConnectionGraph::print_statistics() {
5181   tty->print_cr("No escape = %d, Arg escape = %d, Global escape = %d", Atomic::load(&_no_escape_counter), Atomic::load(&_arg_escape_counter), Atomic::load(&_global_escape_counter));
5182 }
5183 
5184 void ConnectionGraph::escape_state_statistics(GrowableArray<JavaObjectNode*>& java_objects_worklist) {
5185   if (!PrintOptoStatistics || (_invocation > 0)) { // Collect data only for the first invocation
5186     return;
5187   }
5188   for (int next = 0; next < java_objects_worklist.length(); ++next) {
5189     JavaObjectNode* ptn = java_objects_worklist.at(next);
5190     if (ptn->ideal_node()->is_Allocate()) {
5191       if (ptn->escape_state() == PointsToNode::NoEscape) {
5192         Atomic::inc(&ConnectionGraph::_no_escape_counter);
5193       } else if (ptn->escape_state() == PointsToNode::ArgEscape) {
5194         Atomic::inc(&ConnectionGraph::_arg_escape_counter);
5195       } else if (ptn->escape_state() == PointsToNode::GlobalEscape) {
5196         Atomic::inc(&ConnectionGraph::_global_escape_counter);
5197       } else {
5198         assert(false, "Unexpected Escape State");
5199       }
5200     }
5201   }
5202 }
5203 
5204 void ConnectionGraph::trace_es_update_helper(PointsToNode* ptn, PointsToNode::EscapeState es, bool fields, const char* reason) const {
5205   if (_compile->directive()->TraceEscapeAnalysisOption) {
5206     assert(ptn != nullptr, "should not be null");
5207     assert(reason != nullptr, "should not be null");
5208     ptn->dump_header(true);
5209     PointsToNode::EscapeState new_es = fields ? ptn->escape_state() : es;
5210     PointsToNode::EscapeState new_fields_es = fields ? es : ptn->fields_escape_state();
5211     tty->print_cr("-> %s(%s) %s", esc_names[(int)new_es], esc_names[(int)new_fields_es], reason);
5212   }
5213 }
5214 
5215 const char* ConnectionGraph::trace_propagate_message(PointsToNode* from) const {
5216   if (_compile->directive()->TraceEscapeAnalysisOption) {
5217     stringStream ss;
5218     ss.print("propagated from: ");
5219     from->dump(true, &ss, false);
5220     return ss.as_string();
5221   } else {
5222     return nullptr;
5223   }
5224 }
5225 
5226 const char* ConnectionGraph::trace_arg_escape_message(CallNode* call) const {
5227   if (_compile->directive()->TraceEscapeAnalysisOption) {
5228     stringStream ss;
5229     ss.print("escapes as arg to:");
5230     call->dump("", false, &ss);
5231     return ss.as_string();
5232   } else {
5233     return nullptr;
5234   }
5235 }
5236 
5237 const char* ConnectionGraph::trace_merged_message(PointsToNode* other) const {
5238   if (_compile->directive()->TraceEscapeAnalysisOption) {
5239     stringStream ss;
5240     ss.print("is merged with other object: ");
5241     other->dump_header(true, &ss);
5242     return ss.as_string();
5243   } else {
5244     return nullptr;
5245   }
5246 }
5247 
5248 #endif
5249 
5250 void ConnectionGraph::record_for_optimizer(Node *n) {
5251   _igvn->_worklist.push(n);
5252   _igvn->add_users_to_worklist(n);
5253 }