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/arraycopynode.hpp"
  34 #include "opto/c2compiler.hpp"
  35 #include "opto/callnode.hpp"
  36 #include "opto/castnode.hpp"
  37 #include "opto/cfgnode.hpp"
  38 #include "opto/compile.hpp"
  39 #include "opto/escape.hpp"
  40 #include "opto/inlinetypenode.hpp"
  41 #include "opto/locknode.hpp"
  42 #include "opto/macro.hpp"
  43 #include "opto/movenode.hpp"
  44 #include "opto/narrowptrnode.hpp"
  45 #include "opto/phaseX.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         // If MemBarStoreStore has a precedent edge add it to the worklist (like MemBarRelease)
 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. Expand flat accesses if the object does not escape. This adds nodes to
 429   // the graph, so it has to be after split_unique_types. This expands atomic
 430   // mismatched accesses (though encapsulated in LoadFlats and StoreFlats) into
 431   // non-mismatched accesses, so it is better before reduce allocation merges.
 432   if (has_non_escaping_obj) {
 433     optimize_flat_accesses(sfn_worklist);
 434   }
 435 
 436   // 7. Reduce allocation merges used as debug information. This is done after
 437   // split_unique_types because the methods used to create SafePointScalarObject
 438   // need to traverse the memory graph to find values for object fields. We also
 439   // set to null the scalarized inputs of reducible Phis so that the Allocate
 440   // that they point can be later scalar replaced.
 441   bool delay = _igvn->delay_transform();
 442   _igvn->set_delay_transform(true);
 443   for (uint i = 0; i < reducible_merges.size(); i++) {
 444     Node* n = reducible_merges.at(i);
 445     if (n->outcnt() > 0) {
 446       if (!reduce_phi_on_safepoints(n->as_Phi())) {
 447         NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 448         C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
 449         return false;
 450       }
 451 
 452       // Now we set the scalar replaceable inputs of ophi to null, which is
 453       // the last piece that would prevent it from being scalar replaceable.
 454       reset_scalar_replaceable_entries(n->as_Phi());
 455     }
 456   }
 457   _igvn->set_delay_transform(delay);
 458 
 459   // Annotate at safepoints if they have <= ArgEscape objects in their scope and at
 460   // java calls if they pass ArgEscape objects as parameters.
 461   if (has_non_escaping_obj &&
 462       (C->env()->should_retain_local_variables() ||
 463        C->env()->jvmti_can_get_owned_monitor_info() ||
 464        C->env()->jvmti_can_walk_any_space() ||
 465        DeoptimizeObjectsALot)) {
 466     int sfn_length = sfn_worklist.length();
 467     for (int next = 0; next < sfn_length; next++) {
 468       SafePointNode* sfn = sfn_worklist.at(next);
 469       sfn->set_has_ea_local_in_scope(has_ea_local_in_scope(sfn));
 470       if (sfn->is_CallJava()) {
 471         CallJavaNode* call = sfn->as_CallJava();
 472         call->set_arg_escape(has_arg_escape(call));
 473       }
 474     }
 475   }
 476 
 477   NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 478   return has_non_escaping_obj;
 479 }
 480 
 481 // Check if it's profitable to reduce the Phi passed as parameter.  Returns true
 482 // if at least one scalar replaceable allocation participates in the merge.
 483 bool ConnectionGraph::can_reduce_phi_check_inputs(PhiNode* ophi) const {
 484   bool found_sr_allocate = false;
 485 
 486   for (uint i = 1; i < ophi->req(); i++) {
 487     JavaObjectNode* ptn = unique_java_object(ophi->in(i));
 488     if (ptn != nullptr && ptn->scalar_replaceable()) {
 489       AllocateNode* alloc = ptn->ideal_node()->as_Allocate();
 490 
 491       // Don't handle arrays.
 492       if (alloc->Opcode() != Op_Allocate) {
 493         assert(alloc->Opcode() == Op_AllocateArray, "Unexpected type of allocation.");
 494         continue;
 495       }
 496 
 497       if (PhaseMacroExpand::can_eliminate_allocation(_igvn, alloc, nullptr)) {
 498         found_sr_allocate = true;
 499       } else {
 500         NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("%dth input of Phi %d is SR but can't be eliminated.", i, ophi->_idx);)
 501         ptn->set_scalar_replaceable(false);
 502       }
 503     }
 504   }
 505 
 506   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);)
 507   return found_sr_allocate;
 508 }
 509 
 510 // We can reduce the Cmp if it's a comparison between the Phi and a constant.
 511 // I require the 'other' input to be a constant so that I can move the Cmp
 512 // around safely.
 513 bool ConnectionGraph::can_reduce_cmp(Node* n, Node* cmp) const {
 514   assert(cmp->Opcode() == Op_CmpP || cmp->Opcode() == Op_CmpN, "not expected node: %s", cmp->Name());
 515   Node* left = cmp->in(1);
 516   Node* right = cmp->in(2);
 517 
 518   return (left == n || right == n) &&
 519          (left->is_Con() || right->is_Con()) &&
 520          cmp->outcnt() == 1;
 521 }
 522 
 523 // We are going to check if any of the SafePointScalarMerge entries
 524 // in the SafePoint reference the Phi that we are checking.
 525 bool ConnectionGraph::has_been_reduced(PhiNode* n, SafePointNode* sfpt) const {
 526   JVMState *jvms = sfpt->jvms();
 527 
 528   for (uint i = jvms->debug_start(); i < jvms->debug_end(); i++) {
 529     Node* sfpt_in = sfpt->in(i);
 530     if (sfpt_in->is_SafePointScalarMerge()) {
 531       SafePointScalarMergeNode* smerge = sfpt_in->as_SafePointScalarMerge();
 532       Node* nsr_ptr = sfpt->in(smerge->merge_pointer_idx(jvms));
 533       if (nsr_ptr == n) {
 534         return true;
 535       }
 536     }
 537   }
 538 
 539   return false;
 540 }
 541 
 542 // Check if we are able to untangle the merge. The following patterns are
 543 // supported:
 544 //  - Phi -> SafePoints
 545 //  - Phi -> CmpP/N
 546 //  - Phi -> AddP -> Load
 547 //  - Phi -> CastPP -> SafePoints
 548 //  - Phi -> CastPP -> AddP -> Load
 549 bool ConnectionGraph::can_reduce_check_users(Node* n, uint nesting) const {
 550   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 551     Node* use = n->fast_out(i);
 552 
 553     if (use->is_SafePoint()) {
 554       if (use->is_Call() && use->as_Call()->has_non_debug_use(n)) {
 555         NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. Call has non_debug_use().", n->_idx, _invocation);)
 556         return false;
 557       } else if (has_been_reduced(n->is_Phi() ? n->as_Phi() : n->as_CastPP()->in(1)->as_Phi(), use->as_SafePoint())) {
 558         NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. It has already been reduced.", n->_idx, _invocation);)
 559         return false;
 560       }
 561     } else if (use->is_AddP()) {
 562       Node* addp = use;
 563       for (DUIterator_Fast jmax, j = addp->fast_outs(jmax); j < jmax; j++) {
 564         Node* use_use = addp->fast_out(j);
 565         const Type* load_type = _igvn->type(use_use);
 566 
 567         if (!use_use->is_Load() || !use_use->as_Load()->can_split_through_phi_base(_igvn)) {
 568           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());)
 569           return false;
 570         } else if (load_type->isa_narrowklass() || load_type->isa_klassptr()) {
 571           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());)
 572           return false;
 573         }
 574       }
 575     } else if (nesting > 0) {
 576       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);)
 577       return false;
 578     } else if (use->is_CastPP()) {
 579       const Type* cast_t = _igvn->type(use);
 580       if (cast_t == nullptr || cast_t->make_ptr()->isa_instptr() == nullptr) {
 581 #ifndef PRODUCT
 582         if (TraceReduceAllocationMerges) {
 583           tty->print_cr("Can NOT reduce Phi %d on invocation %d. CastPP is not to an instance.", n->_idx, _invocation);
 584           use->dump();
 585         }
 586 #endif
 587         return false;
 588       }
 589 
 590       bool is_trivial_control = use->in(0) == nullptr || use->in(0) == n->in(0);
 591       if (!is_trivial_control) {
 592         // If it's not a trivial control then we check if we can reduce the
 593         // CmpP/N used by the If controlling the cast.
 594         if (use->in(0)->is_IfTrue() || use->in(0)->is_IfFalse()) {
 595           Node* iff = use->in(0)->in(0);
 596           // We may have an OpaqueNotNull node between If and Bool nodes. But we could also have a sub class of IfNode,
 597           // for example, an OuterStripMinedLoopEnd or a Parse Predicate. Bail out in all these cases.
 598           bool can_reduce = (iff->Opcode() == Op_If) && iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp();
 599           if (can_reduce) {
 600             Node* iff_cmp = iff->in(1)->in(1);
 601             int opc = iff_cmp->Opcode();
 602             can_reduce = (opc == Op_CmpP || opc == Op_CmpN) && can_reduce_cmp(n, iff_cmp);
 603           }
 604           if (!can_reduce) {
 605 #ifndef PRODUCT
 606             if (TraceReduceAllocationMerges) {
 607               tty->print_cr("Can NOT reduce Phi %d on invocation %d. CastPP %d doesn't have simple control.", n->_idx, _invocation, use->_idx);
 608               n->dump(5);
 609             }
 610 #endif
 611             return false;
 612           }
 613         }
 614       }
 615 
 616       if (!can_reduce_check_users(use, nesting+1)) {
 617         return false;
 618       }
 619     } else if (use->Opcode() == Op_CmpP || use->Opcode() == Op_CmpN) {
 620       if (!can_reduce_cmp(n, use)) {
 621         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);)
 622         return false;
 623       }
 624     } else {
 625       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());)
 626       return false;
 627     }
 628   }
 629 
 630   return true;
 631 }
 632 
 633 // Returns true if: 1) It's profitable to reduce the merge, and 2) The Phi is
 634 // only used in some certain code shapes. Check comments in
 635 // 'can_reduce_phi_inputs' and 'can_reduce_phi_users' for more
 636 // details.
 637 bool ConnectionGraph::can_reduce_phi(PhiNode* ophi) const {
 638   // If there was an error attempting to reduce allocation merges for this
 639   // method we might have disabled the compilation and be retrying with RAM
 640   // disabled.
 641   if (!_compile->do_reduce_allocation_merges() || ophi->region()->Opcode() != Op_Region) {
 642     return false;
 643   }
 644 
 645   const Type* phi_t = _igvn->type(ophi);
 646   if (phi_t == nullptr ||
 647       phi_t->make_ptr() == nullptr ||
 648       phi_t->make_ptr()->isa_aryptr() != nullptr) {
 649     return false;
 650   }
 651 
 652   if (!can_reduce_phi_check_inputs(ophi) || !can_reduce_check_users(ophi, /* nesting: */ 0)) {
 653     return false;
 654   }
 655 
 656   NOT_PRODUCT(if (TraceReduceAllocationMerges) { tty->print_cr("Can reduce Phi %d during invocation %d: ", ophi->_idx, _invocation); })
 657   return true;
 658 }
 659 
 660 // This method will return a CmpP/N that we need to use on the If controlling a
 661 // CastPP after it was split. This method is only called on bases that are
 662 // nullable therefore we always need a controlling if for the splitted CastPP.
 663 //
 664 // 'curr_ctrl' is the control of the CastPP that we want to split through phi.
 665 // If the CastPP currently doesn't have a control then the CmpP/N will be
 666 // against the null constant, otherwise it will be against the constant input of
 667 // the existing CmpP/N. It's guaranteed that there will be a CmpP/N in the later
 668 // case because we have constraints on it and because the CastPP has a control
 669 // input.
 670 Node* ConnectionGraph::specialize_cmp(Node* base, Node* curr_ctrl) {
 671   const Type* t = base->bottom_type();
 672   Node* con = nullptr;
 673 
 674   if (curr_ctrl == nullptr || curr_ctrl->is_Region()) {
 675     con = _igvn->zerocon(t->basic_type());
 676   } else {
 677     // can_reduce_check_users() verified graph: true/false -> if -> bool -> cmp
 678     assert(curr_ctrl->in(0)->Opcode() == Op_If, "unexpected node %s", curr_ctrl->in(0)->Name());
 679     Node* bol = curr_ctrl->in(0)->in(1);
 680     assert(bol->is_Bool(), "unexpected node %s", bol->Name());
 681     Node* curr_cmp = bol->in(1);
 682     assert(curr_cmp->Opcode() == Op_CmpP || curr_cmp->Opcode() == Op_CmpN, "unexpected node %s", curr_cmp->Name());
 683     con = curr_cmp->in(1)->is_Con() ? curr_cmp->in(1) : curr_cmp->in(2);
 684   }
 685 
 686   return CmpNode::make(base, con, t->basic_type());
 687 }
 688 
 689 // This method 'specializes' the CastPP passed as parameter to the base passed
 690 // as parameter. Note that the existing CastPP input is a Phi. "Specialize"
 691 // means that the CastPP now will be specific for a given base instead of a Phi.
 692 // An If-Then-Else-Region block is inserted to control the CastPP. The control
 693 // of the CastPP is a copy of the current one (if there is one) or a check
 694 // against null.
 695 //
 696 // Before:
 697 //
 698 //    C1     C2  ... Cn
 699 //     \      |      /
 700 //      \     |     /
 701 //       \    |    /
 702 //        \   |   /
 703 //         \  |  /
 704 //          \ | /
 705 //           \|/
 706 //          Region     B1      B2  ... Bn
 707 //            |          \      |      /
 708 //            |           \     |     /
 709 //            |            \    |    /
 710 //            |             \   |   /
 711 //            |              \  |  /
 712 //            |               \ | /
 713 //            ---------------> Phi
 714 //                              |
 715 //                      X       |
 716 //                      |       |
 717 //                      |       |
 718 //                      ------> CastPP
 719 //
 720 // After (only partial illustration; base = B2, current_control = C2):
 721 //
 722 //                      C2
 723 //                      |
 724 //                      If
 725 //                     / \
 726 //                    /   \
 727 //                   T     F
 728 //                  /\     /
 729 //                 /  \   /
 730 //                /    \ /
 731 //      C1    CastPP   Reg        Cn
 732 //       |              |          |
 733 //       |              |          |
 734 //       |              |          |
 735 //       -------------- | ----------
 736 //                    | | |
 737 //                    Region
 738 //
 739 Node* ConnectionGraph::specialize_castpp(Node* castpp, Node* base, Node* current_control) {
 740   Node* control_successor  = current_control->unique_ctrl_out();
 741   Node* cmp                = _igvn->transform(specialize_cmp(base, castpp->in(0)));
 742   Node* bol                = _igvn->transform(new BoolNode(cmp, BoolTest::ne));
 743   IfNode* if_ne            = _igvn->transform(new IfNode(current_control, bol, PROB_MIN, COUNT_UNKNOWN))->as_If();
 744   Node* not_eq_control     = _igvn->transform(new IfTrueNode(if_ne));
 745   Node* yes_eq_control     = _igvn->transform(new IfFalseNode(if_ne));
 746   Node* end_region         = _igvn->transform(new RegionNode(3));
 747 
 748   // Insert the new if-else-region block into the graph
 749   end_region->set_req(1, not_eq_control);
 750   end_region->set_req(2, yes_eq_control);
 751   control_successor->replace_edge(current_control, end_region, _igvn);
 752 
 753   _igvn->_worklist.push(current_control);
 754   _igvn->_worklist.push(control_successor);
 755 
 756   return _igvn->transform(ConstraintCastNode::make_cast_for_type(not_eq_control, base, _igvn->type(castpp), ConstraintCastNode::UnconditionalDependency, nullptr));
 757 }
 758 
 759 Node* ConnectionGraph::split_castpp_load_through_phi(Node* curr_addp, Node* curr_load, Node* region, GrowableArray<Node*>* bases_for_loads, GrowableArray<Node *>  &alloc_worklist) {
 760   const Type* load_type = _igvn->type(curr_load);
 761   Node* nsr_value = _igvn->zerocon(load_type->basic_type());
 762   Node* memory = curr_load->in(MemNode::Memory);
 763 
 764   // The data_phi merging the loads needs to be nullable if
 765   // we are loading pointers.
 766   if (load_type->make_ptr() != nullptr) {
 767     if (load_type->isa_narrowoop()) {
 768       load_type = load_type->meet(TypeNarrowOop::NULL_PTR);
 769     } else if (load_type->isa_ptr()) {
 770       load_type = load_type->meet(TypePtr::NULL_PTR);
 771     } else {
 772       assert(false, "Unexpected load ptr type.");
 773     }
 774   }
 775 
 776   Node* data_phi = PhiNode::make(region, nsr_value, load_type);
 777 
 778   for (int i = 1; i < bases_for_loads->length(); i++) {
 779     Node* base = bases_for_loads->at(i);
 780     Node* cmp_region = nullptr;
 781     if (base != nullptr) {
 782       if (base->is_CFG()) { // means that we added a CastPP as child of this CFG node
 783         cmp_region = base->unique_ctrl_out_or_null();
 784         assert(cmp_region != nullptr, "There should be.");
 785         base = base->find_out_with(Op_CastPP);
 786       }
 787 
 788       Node* addr = _igvn->transform(new AddPNode(base, base, curr_addp->in(AddPNode::Offset)));
 789       Node* mem = (memory->is_Phi() && (memory->in(0) == region)) ? memory->in(i) : memory;
 790       Node* load = curr_load->clone();
 791       load->set_req(0, nullptr);
 792       load->set_req(1, mem);
 793       load->set_req(2, addr);
 794 
 795       if (cmp_region != nullptr) { // see comment on previous if
 796         Node* intermediate_phi = PhiNode::make(cmp_region, nsr_value, load_type);
 797         intermediate_phi->set_req(1, _igvn->transform(load));
 798         load = intermediate_phi;
 799       }
 800 
 801       data_phi->set_req(i, _igvn->transform(load));
 802     } else {
 803       // Just use the default, which is already in phi
 804     }
 805   }
 806 
 807   // Takes care of updating CG and split_unique_types worklists due
 808   // to cloned AddP->Load.
 809   updates_after_load_split(data_phi, curr_load, alloc_worklist);
 810 
 811   return _igvn->transform(data_phi);
 812 }
 813 
 814 // This method only reduces CastPP fields loads; SafePoints are handled
 815 // separately. The idea here is basically to clone the CastPP and place copies
 816 // on each input of the Phi, including non-scalar replaceable inputs.
 817 // Experimentation shows that the resulting IR graph is simpler that way than if
 818 // we just split the cast through scalar-replaceable inputs.
 819 //
 820 // The reduction process requires that CastPP's control be one of:
 821 //  1) no control,
 822 //  2) the same region as Ophi, or
 823 //  3) an IfTrue/IfFalse coming from an CmpP/N between Ophi and a constant.
 824 //
 825 // After splitting the CastPP we'll put it under an If-Then-Else-Region control
 826 // flow. If the CastPP originally had an IfTrue/False control input then we'll
 827 // use a similar CmpP/N to control the new If-Then-Else-Region. Otherwise, we'll
 828 // juse use a CmpP/N against the null constant.
 829 //
 830 // The If-Then-Else-Region isn't always needed. For instance, if input to
 831 // splitted cast was not nullable (or if it was the null constant) then we don't
 832 // need (shouldn't) use a CastPP at all.
 833 //
 834 // After the casts are splitted we'll split the AddP->Loads through the Phi and
 835 // connect them to the just split CastPPs.
 836 //
 837 // Before (CastPP control is same as Phi):
 838 //
 839 //          Region     Allocate   Null    Call
 840 //            |             \      |      /
 841 //            |              \     |     /
 842 //            |               \    |    /
 843 //            |                \   |   /
 844 //            |                 \  |  /
 845 //            |                  \ | /
 846 //            ------------------> Phi            # Oop Phi
 847 //            |                    |
 848 //            |                    |
 849 //            |                    |
 850 //            |                    |
 851 //            ----------------> CastPP
 852 //                                 |
 853 //                               AddP
 854 //                                 |
 855 //                               Load
 856 //
 857 // After (Very much simplified):
 858 //
 859 //                         Call  Null
 860 //                            \  /
 861 //                            CmpP
 862 //                             |
 863 //                           Bool#NE
 864 //                             |
 865 //                             If
 866 //                            / \
 867 //                           T   F
 868 //                          / \ /
 869 //                         /   R
 870 //                     CastPP  |
 871 //                       |     |
 872 //                     AddP    |
 873 //                       |     |
 874 //                     Load    |
 875 //                         \   |   0
 876 //            Allocate      \  |  /
 877 //                \          \ | /
 878 //               AddP         Phi
 879 //                  \         /
 880 //                 Load      /
 881 //                    \  0  /
 882 //                     \ | /
 883 //                      \|/
 884 //                      Phi        # "Field" Phi
 885 //
 886 void ConnectionGraph::reduce_phi_on_castpp_field_load(Node* curr_castpp, GrowableArray<Node *>  &alloc_worklist, GrowableArray<Node *>  &memnode_worklist) {
 887   Node* ophi = curr_castpp->in(1);
 888   assert(ophi->is_Phi(), "Expected this to be a Phi node.");
 889 
 890   // Identify which base should be used for AddP->Load later when spliting the
 891   // CastPP->Loads through ophi. Three kind of values may be stored in this
 892   // array, depending on the nullability status of the corresponding input in
 893   // ophi.
 894   //
 895   //  - nullptr:    Meaning that the base is actually the null constant and therefore
 896   //                we won't try to load from it.
 897   //
 898   //  - CFG Node:   Meaning that the base is a CastPP that was specialized for
 899   //                this input of Ophi. I.e., we added an If->Then->Else-Region
 900   //                that will 'activate' the CastPp only when the input is not Null.
 901   //
 902   //  - Other Node: Meaning that the base is not nullable and therefore we'll try
 903   //                to load directly from it.
 904   GrowableArray<Node*> bases_for_loads(ophi->req(), ophi->req(), nullptr);
 905 
 906   for (uint i = 1; i < ophi->req(); i++) {
 907     Node* base = ophi->in(i);
 908     const Type* base_t = _igvn->type(base);
 909 
 910     if (base_t->maybe_null()) {
 911       if (base->is_Con()) {
 912         // Nothing todo as bases_for_loads[i] is already null
 913       } else {
 914         Node* new_castpp = specialize_castpp(curr_castpp, base, ophi->in(0)->in(i));
 915         bases_for_loads.at_put(i, new_castpp->in(0)); // Use the ctrl of the new node just as a flag
 916       }
 917     } else {
 918       bases_for_loads.at_put(i, base);
 919     }
 920   }
 921 
 922   // Now let's split the CastPP->Loads through the Phi
 923   for (int i = curr_castpp->outcnt()-1; i >= 0;) {
 924     Node* use = curr_castpp->raw_out(i);
 925     if (use->is_AddP()) {
 926       for (int j = use->outcnt()-1; j >= 0;) {
 927         Node* use_use = use->raw_out(j);
 928         assert(use_use->is_Load(), "Expected this to be a Load node.");
 929 
 930         // We can't make an unconditional load from a nullable input. The
 931         // 'split_castpp_load_through_phi` method will add an
 932         // 'If-Then-Else-Region` around nullable bases and only load from them
 933         // when the input is not null.
 934         Node* phi = split_castpp_load_through_phi(use, use_use, ophi->in(0), &bases_for_loads, alloc_worklist);
 935         _igvn->replace_node(use_use, phi);
 936 
 937         --j;
 938         j = MIN2(j, (int)use->outcnt()-1);
 939       }
 940 
 941       _igvn->remove_dead_node(use);
 942     }
 943     --i;
 944     i = MIN2(i, (int)curr_castpp->outcnt()-1);
 945   }
 946 }
 947 
 948 // This method split a given CmpP/N through the Phi used in one of its inputs.
 949 // As a result we convert a comparison with a pointer to a comparison with an
 950 // integer.
 951 // The only requirement is that one of the inputs of the CmpP/N must be a Phi
 952 // while the other must be a constant.
 953 // The splitting process is basically just cloning the CmpP/N above the input
 954 // Phi.  However, some (most) of the cloned CmpP/Ns won't be requred because we
 955 // can prove at compile time the result of the comparison.
 956 //
 957 // Before:
 958 //
 959 //             in1    in2 ... inN
 960 //              \      |      /
 961 //               \     |     /
 962 //                \    |    /
 963 //                 \   |   /
 964 //                  \  |  /
 965 //                   \ | /
 966 //                    Phi
 967 //                     |   Other
 968 //                     |    /
 969 //                     |   /
 970 //                     |  /
 971 //                    CmpP/N
 972 //
 973 // After:
 974 //
 975 //        in1  Other   in2 Other  inN  Other
 976 //         |    |      |   |      |    |
 977 //         \    |      |   |      |    |
 978 //          \  /       |   /      |    /
 979 //          CmpP/N    CmpP/N     CmpP/N
 980 //          Bool      Bool       Bool
 981 //            \        |        /
 982 //             \       |       /
 983 //              \      |      /
 984 //               \     |     /
 985 //                \    |    /
 986 //                 \   |   /
 987 //                  \  |  /
 988 //                   \ | /
 989 //                    Phi
 990 //                     |
 991 //                     |   Zero
 992 //                     |    /
 993 //                     |   /
 994 //                     |  /
 995 //                     CmpI
 996 //
 997 //
 998 void ConnectionGraph::reduce_phi_on_cmp(Node* cmp) {
 999   Node* ophi = cmp->in(1)->is_Con() ? cmp->in(2) : cmp->in(1);
1000   assert(ophi->is_Phi(), "Expected this to be a Phi node.");
1001 
1002   Node* other = cmp->in(1)->is_Con() ? cmp->in(1) : cmp->in(2);
1003   Node* zero = _igvn->intcon(0);
1004   Node* one = _igvn->intcon(1);
1005   BoolTest::mask mask = cmp->unique_out()->as_Bool()->_test._test;
1006 
1007   // This Phi will merge the result of the Cmps split through the Phi
1008   Node* res_phi = PhiNode::make(ophi->in(0), zero, TypeInt::INT);
1009 
1010   for (uint i=1; i<ophi->req(); i++) {
1011     Node* ophi_input = ophi->in(i);
1012     Node* res_phi_input = nullptr;
1013 
1014     const TypeInt* tcmp = optimize_ptr_compare(ophi_input, other);
1015     if (tcmp->singleton()) {
1016       if ((mask == BoolTest::mask::eq && tcmp == TypeInt::CC_EQ) ||
1017           (mask == BoolTest::mask::ne && tcmp == TypeInt::CC_GT)) {
1018         res_phi_input = one;
1019       } else {
1020         res_phi_input = zero;
1021       }
1022     } else {
1023       Node* ncmp = _igvn->transform(cmp->clone());
1024       ncmp->set_req(1, ophi_input);
1025       ncmp->set_req(2, other);
1026       Node* bol = _igvn->transform(new BoolNode(ncmp, mask));
1027       res_phi_input = bol->as_Bool()->as_int_value(_igvn);
1028     }
1029 
1030     res_phi->set_req(i, res_phi_input);
1031   }
1032 
1033   // This CMP always compares whether the output of "res_phi" is TRUE as far as the "mask".
1034   Node* new_cmp = _igvn->transform(new CmpINode(_igvn->transform(res_phi), (mask == BoolTest::mask::eq) ? one : zero));
1035   _igvn->replace_node(cmp, new_cmp);
1036 }
1037 
1038 // Push the newly created AddP on alloc_worklist and patch
1039 // the connection graph. Note that the changes in the CG below
1040 // won't affect the ES of objects since the new nodes have the
1041 // same status as the old ones.
1042 void ConnectionGraph::updates_after_load_split(Node* data_phi, Node* previous_load, GrowableArray<Node *>  &alloc_worklist) {
1043   assert(data_phi != nullptr, "Output of split_through_phi is null.");
1044   assert(data_phi != previous_load, "Output of split_through_phi is same as input.");
1045   assert(data_phi->is_Phi(), "Output of split_through_phi isn't a Phi.");
1046 
1047   if (data_phi == nullptr || !data_phi->is_Phi()) {
1048     // Make this a retry?
1049     return ;
1050   }
1051 
1052   Node* previous_addp = previous_load->in(MemNode::Address);
1053   FieldNode* fn = ptnode_adr(previous_addp->_idx)->as_Field();
1054   for (uint i = 1; i < data_phi->req(); i++) {
1055     Node* new_load = data_phi->in(i);
1056 
1057     if (new_load->is_Phi()) {
1058       // new_load is currently the "intermediate_phi" from an specialized
1059       // CastPP.
1060       new_load = new_load->in(1);
1061     }
1062 
1063     // "new_load" might actually be a constant, parameter, etc.
1064     if (new_load->is_Load()) {
1065       Node* new_addp = new_load->in(MemNode::Address);
1066       Node* base = get_addp_base(new_addp);
1067 
1068       // The base might not be something that we can create an unique
1069       // type for. If that's the case we are done with that input.
1070       PointsToNode* jobj_ptn = unique_java_object(base);
1071       if (jobj_ptn == nullptr || !jobj_ptn->scalar_replaceable()) {
1072         continue;
1073       }
1074 
1075       // Push to alloc_worklist since the base has an unique_type
1076       alloc_worklist.append_if_missing(new_addp);
1077 
1078       // Now let's add the node to the connection graph
1079       _nodes.at_grow(new_addp->_idx, nullptr);
1080       add_field(new_addp, fn->escape_state(), fn->offset());
1081       add_base(ptnode_adr(new_addp->_idx)->as_Field(), ptnode_adr(base->_idx));
1082 
1083       // If the load doesn't load an object then it won't be
1084       // part of the connection graph
1085       PointsToNode* curr_load_ptn = ptnode_adr(previous_load->_idx);
1086       if (curr_load_ptn != nullptr) {
1087         _nodes.at_grow(new_load->_idx, nullptr);
1088         add_local_var(new_load, curr_load_ptn->escape_state());
1089         add_edge(ptnode_adr(new_load->_idx), ptnode_adr(new_addp->_idx)->as_Field());
1090       }
1091     }
1092   }
1093 }
1094 
1095 void ConnectionGraph::reduce_phi_on_field_access(Node* previous_addp, GrowableArray<Node *>  &alloc_worklist) {
1096   // We'll pass this to 'split_through_phi' so that it'll do the split even
1097   // though the load doesn't have an unique instance type.
1098   bool ignore_missing_instance_id = true;
1099 
1100   // All AddPs are present in the connection graph
1101   FieldNode* fn = ptnode_adr(previous_addp->_idx)->as_Field();
1102 
1103   // Iterate over AddP looking for a Load
1104   for (int k = previous_addp->outcnt()-1; k >= 0;) {
1105     Node* previous_load = previous_addp->raw_out(k);
1106     if (previous_load->is_Load()) {
1107       Node* data_phi = previous_load->as_Load()->split_through_phi(_igvn, ignore_missing_instance_id);
1108 
1109       // Takes care of updating CG and split_unique_types worklists due to cloned
1110       // AddP->Load.
1111       updates_after_load_split(data_phi, previous_load, alloc_worklist);
1112 
1113       _igvn->replace_node(previous_load, data_phi);
1114     }
1115     --k;
1116     k = MIN2(k, (int)previous_addp->outcnt()-1);
1117   }
1118 
1119   // Remove the old AddP from the processing list because it's dead now
1120   assert(previous_addp->outcnt() == 0, "AddP should be dead now.");
1121   alloc_worklist.remove_if_existing(previous_addp);
1122 }
1123 
1124 // Create a 'selector' Phi based on the inputs of 'ophi'. If index 'i' of the
1125 // selector is:
1126 //    -> a '-1' constant, the i'th input of the original Phi is NSR.
1127 //    -> a 'x' constant >=0, the i'th input of of original Phi will be SR and
1128 //       the info about the scalarized object will be at index x of ObjectMergeValue::possible_objects
1129 PhiNode* ConnectionGraph::create_selector(PhiNode* ophi) const {
1130   Node* minus_one = _igvn->register_new_node_with_optimizer(ConINode::make(-1));
1131   Node* selector  = _igvn->register_new_node_with_optimizer(PhiNode::make(ophi->region(), minus_one, TypeInt::INT));
1132   uint number_of_sr_objects = 0;
1133   for (uint i = 1; i < ophi->req(); i++) {
1134     Node* base = ophi->in(i);
1135     JavaObjectNode* ptn = unique_java_object(base);
1136 
1137     if (ptn != nullptr && ptn->scalar_replaceable()) {
1138       Node* sr_obj_idx = _igvn->register_new_node_with_optimizer(ConINode::make(number_of_sr_objects));
1139       selector->set_req(i, sr_obj_idx);
1140       number_of_sr_objects++;
1141     }
1142   }
1143 
1144   return selector->as_Phi();
1145 }
1146 
1147 // Returns true if the AddP node 'n' has at least one base that is a reducible
1148 // merge. If the base is a CastPP/CheckCastPP then the input of the cast is
1149 // checked instead.
1150 bool ConnectionGraph::has_reducible_merge_base(AddPNode* n, Unique_Node_List &reducible_merges) {
1151   PointsToNode* ptn = ptnode_adr(n->_idx);
1152   if (ptn == nullptr || !ptn->is_Field() || ptn->as_Field()->base_count() < 2) {
1153     return false;
1154   }
1155 
1156   for (BaseIterator i(ptn->as_Field()); i.has_next(); i.next()) {
1157     Node* base = i.get()->ideal_node();
1158 
1159     if (reducible_merges.member(base)) {
1160       return true;
1161     }
1162 
1163     if (base->is_CastPP() || base->is_CheckCastPP()) {
1164       base = base->in(1);
1165       if (reducible_merges.member(base)) {
1166         return true;
1167       }
1168     }
1169   }
1170 
1171   return false;
1172 }
1173 
1174 // This method will call its helper method to reduce SafePoint nodes that use
1175 // 'ophi' or a casted version of 'ophi'. All SafePoint nodes using the same
1176 // "version" of Phi use the same debug information (regarding the Phi).
1177 // Therefore, I collect all safepoints and patch them all at once.
1178 //
1179 // The safepoints using the Phi node have to be processed before safepoints of
1180 // CastPP nodes. The reason is, when reducing a CastPP we add a reference (the
1181 // NSR merge pointer) to the input of the CastPP (i.e., the Phi) in the
1182 // safepoint. If we process CastPP's safepoints before Phi's safepoints the
1183 // algorithm that process Phi's safepoints will think that the added Phi
1184 // reference is a regular reference.
1185 bool ConnectionGraph::reduce_phi_on_safepoints(PhiNode* ophi) {
1186   PhiNode* selector = create_selector(ophi);
1187   Unique_Node_List safepoints;
1188   Unique_Node_List casts;
1189 
1190   // Just collect the users of the Phis for later processing
1191   // in the needed order.
1192   for (uint i = 0; i < ophi->outcnt(); i++) {
1193     Node* use = ophi->raw_out(i);
1194     if (use->is_SafePoint()) {
1195       safepoints.push(use);
1196     } else if (use->is_CastPP()) {
1197       casts.push(use);
1198     } else {
1199       assert(use->outcnt() == 0, "Only CastPP & SafePoint users should be left.");
1200     }
1201   }
1202 
1203   // Need to process safepoints using the Phi first
1204   if (!reduce_phi_on_safepoints_helper(ophi, nullptr, selector, safepoints)) {
1205     return false;
1206   }
1207 
1208   // Now process CastPP->safepoints
1209   for (uint i = 0; i < casts.size(); i++) {
1210     Node* cast = casts.at(i);
1211     Unique_Node_List cast_sfpts;
1212 
1213     for (DUIterator_Fast jmax, j = cast->fast_outs(jmax); j < jmax; j++) {
1214       Node* use_use = cast->fast_out(j);
1215       if (use_use->is_SafePoint()) {
1216         cast_sfpts.push(use_use);
1217       } else {
1218         assert(use_use->outcnt() == 0, "Only SafePoint users should be left.");
1219       }
1220     }
1221 
1222     if (!reduce_phi_on_safepoints_helper(ophi, cast, selector, cast_sfpts)) {
1223       return false;
1224     }
1225   }
1226 
1227   return true;
1228 }
1229 
1230 // This method will create a SafePointScalarMERGEnode for each SafePoint in
1231 // 'safepoints'. It then will iterate on the inputs of 'ophi' and create a
1232 // SafePointScalarObjectNode for each scalar replaceable input. Each
1233 // SafePointScalarMergeNode may describe multiple scalar replaced objects -
1234 // check detailed description in SafePointScalarMergeNode class header.
1235 bool ConnectionGraph::reduce_phi_on_safepoints_helper(Node* ophi, Node* cast, Node* selector, Unique_Node_List& safepoints) {
1236   PhaseMacroExpand mexp(*_igvn);
1237   Node* original_sfpt_parent =  cast != nullptr ? cast : ophi;
1238   const TypeOopPtr* merge_t = _igvn->type(original_sfpt_parent)->make_oopptr();
1239 
1240   Node* nsr_merge_pointer = ophi;
1241   if (cast != nullptr) {
1242     const Type* new_t = merge_t->meet(TypePtr::NULL_PTR);
1243     nsr_merge_pointer = _igvn->transform(ConstraintCastNode::make_cast_for_type(cast->in(0), cast->in(1), new_t, ConstraintCastNode::RegularDependency, nullptr));
1244   }
1245 
1246   for (uint spi = 0; spi < safepoints.size(); spi++) {
1247     SafePointNode* sfpt = safepoints.at(spi)->as_SafePoint();
1248     JVMState *jvms      = sfpt->jvms();
1249     uint merge_idx      = (sfpt->req() - jvms->scloff());
1250     int debug_start     = jvms->debug_start();
1251 
1252     SafePointScalarMergeNode* smerge = new SafePointScalarMergeNode(merge_t, merge_idx);
1253     smerge->init_req(0, _compile->root());
1254     _igvn->register_new_node_with_optimizer(smerge);
1255 
1256     // The next two inputs are:
1257     //  (1) A copy of the original pointer to NSR objects.
1258     //  (2) A selector, used to decide if we need to rematerialize an object
1259     //      or use the pointer to a NSR object.
1260     // See more details of these fields in the declaration of SafePointScalarMergeNode
1261     sfpt->add_req(nsr_merge_pointer);
1262     sfpt->add_req(selector);
1263 
1264     for (uint i = 1; i < ophi->req(); i++) {
1265       Node* base = ophi->in(i);
1266       JavaObjectNode* ptn = unique_java_object(base);
1267 
1268       // If the base is not scalar replaceable we don't need to register information about
1269       // it at this time.
1270       if (ptn == nullptr || !ptn->scalar_replaceable()) {
1271         continue;
1272       }
1273 
1274       AllocateNode* alloc = ptn->ideal_node()->as_Allocate();
1275       Unique_Node_List value_worklist;
1276 #ifdef ASSERT
1277       const Type* res_type = alloc->result_cast()->bottom_type();
1278       if (res_type->is_inlinetypeptr() && !Compile::current()->has_circular_inline_type()) {
1279         PhiNode* phi = ophi->as_Phi();
1280         assert(!ophi->as_Phi()->can_push_inline_types_down(_igvn), "missed earlier scalarization opportunity");
1281       }
1282 #endif
1283       SafePointScalarObjectNode* sobj = mexp.create_scalarized_object_description(alloc, sfpt, &value_worklist);
1284       if (sobj == nullptr) {
1285         _compile->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1286         return false;
1287       }
1288 
1289       // Now make a pass over the debug information replacing any references
1290       // to the allocated object with "sobj"
1291       Node* ccpp = alloc->result_cast();
1292       sfpt->replace_edges_in_range(ccpp, sobj, debug_start, jvms->debug_end(), _igvn);
1293 
1294       // Register the scalarized object as a candidate for reallocation
1295       smerge->add_req(sobj);
1296 
1297       // Scalarize inline types that were added to the safepoint.
1298       // Don't allow linking a constant oop (if available) for flat array elements
1299       // because Deoptimization::reassign_flat_array_elements needs field values.
1300       const bool allow_oop = !merge_t->is_flat();
1301       for (uint j = 0; j < value_worklist.size(); ++j) {
1302         InlineTypeNode* vt = value_worklist.at(j)->as_InlineType();
1303         vt->make_scalar_in_safepoints(_igvn, allow_oop);
1304       }
1305     }
1306 
1307     // Replaces debug information references to "original_sfpt_parent" in "sfpt" with references to "smerge"
1308     sfpt->replace_edges_in_range(original_sfpt_parent, smerge, debug_start, jvms->debug_end(), _igvn);
1309 
1310     // The call to 'replace_edges_in_range' above might have removed the
1311     // reference to ophi that we need at _merge_pointer_idx. The line below make
1312     // sure the reference is maintained.
1313     sfpt->set_req(smerge->merge_pointer_idx(jvms), nsr_merge_pointer);
1314     _igvn->_worklist.push(sfpt);
1315   }
1316 
1317   return true;
1318 }
1319 
1320 void ConnectionGraph::reduce_phi(PhiNode* ophi, GrowableArray<Node *>  &alloc_worklist, GrowableArray<Node *>  &memnode_worklist) {
1321   bool delay = _igvn->delay_transform();
1322   _igvn->set_delay_transform(true);
1323   _igvn->hash_delete(ophi);
1324 
1325   // Copying all users first because some will be removed and others won't.
1326   // Ophi also may acquire some new users as part of Cast reduction.
1327   // CastPPs also need to be processed before CmpPs.
1328   Unique_Node_List castpps;
1329   Unique_Node_List others;
1330   for (DUIterator_Fast imax, i = ophi->fast_outs(imax); i < imax; i++) {
1331     Node* use = ophi->fast_out(i);
1332 
1333     if (use->is_CastPP()) {
1334       castpps.push(use);
1335     } else if (use->is_AddP() || use->is_Cmp()) {
1336       others.push(use);
1337     } else {
1338       // Safepoints to be processed later; other users aren't expected here
1339       assert(use->is_SafePoint(), "Unexpected user of reducible Phi %d -> %d:%s:%d", ophi->_idx, use->_idx, use->Name(), use->outcnt());
1340     }
1341   }
1342 
1343   // CastPPs need to be processed before Cmps because during the process of
1344   // splitting CastPPs we make reference to the inputs of the Cmp that is used
1345   // by the If controlling the CastPP.
1346   for (uint i = 0; i < castpps.size(); i++) {
1347     reduce_phi_on_castpp_field_load(castpps.at(i), alloc_worklist, memnode_worklist);
1348   }
1349 
1350   for (uint i = 0; i < others.size(); i++) {
1351     Node* use = others.at(i);
1352 
1353     if (use->is_AddP()) {
1354       reduce_phi_on_field_access(use, alloc_worklist);
1355     } else if(use->is_Cmp()) {
1356       reduce_phi_on_cmp(use);
1357     }
1358   }
1359 
1360   _igvn->set_delay_transform(delay);
1361 }
1362 
1363 void ConnectionGraph::reset_scalar_replaceable_entries(PhiNode* ophi) {
1364   Node* null_ptr            = _igvn->makecon(TypePtr::NULL_PTR);
1365   const TypeOopPtr* merge_t = _igvn->type(ophi)->make_oopptr();
1366   const Type* new_t         = merge_t->meet(TypePtr::NULL_PTR);
1367   Node* new_phi             = _igvn->register_new_node_with_optimizer(PhiNode::make(ophi->region(), null_ptr, new_t));
1368 
1369   for (uint i = 1; i < ophi->req(); i++) {
1370     Node* base          = ophi->in(i);
1371     JavaObjectNode* ptn = unique_java_object(base);
1372 
1373     if (ptn != nullptr && ptn->scalar_replaceable()) {
1374       new_phi->set_req(i, null_ptr);
1375     } else {
1376       new_phi->set_req(i, ophi->in(i));
1377     }
1378   }
1379 
1380   for (int i = ophi->outcnt()-1; i >= 0;) {
1381     Node* out = ophi->raw_out(i);
1382 
1383     if (out->is_ConstraintCast()) {
1384       const Type* out_t = _igvn->type(out)->make_ptr();
1385       const Type* out_new_t = out_t->meet(TypePtr::NULL_PTR);
1386       bool change = out_new_t != out_t;
1387 
1388       for (int j = out->outcnt()-1; change && j >= 0; --j) {
1389         Node* out2 = out->raw_out(j);
1390         if (!out2->is_SafePoint()) {
1391           change = false;
1392           break;
1393         }
1394       }
1395 
1396       if (change) {
1397         Node* new_cast = ConstraintCastNode::make_cast_for_type(out->in(0), out->in(1), out_new_t, ConstraintCastNode::StrongDependency, nullptr);
1398         _igvn->replace_node(out, new_cast);
1399         _igvn->register_new_node_with_optimizer(new_cast);
1400       }
1401     }
1402 
1403     --i;
1404     i = MIN2(i, (int)ophi->outcnt()-1);
1405   }
1406 
1407   _igvn->replace_node(ophi, new_phi);
1408 }
1409 
1410 void ConnectionGraph::verify_ram_nodes(Compile* C, Node* root) {
1411   if (!C->do_reduce_allocation_merges()) return;
1412 
1413   Unique_Node_List ideal_nodes;
1414   ideal_nodes.map(C->live_nodes(), nullptr);  // preallocate space
1415   ideal_nodes.push(root);
1416 
1417   for (uint next = 0; next < ideal_nodes.size(); ++next) {
1418     Node* n = ideal_nodes.at(next);
1419 
1420     if (n->is_SafePointScalarMerge()) {
1421       SafePointScalarMergeNode* merge = n->as_SafePointScalarMerge();
1422 
1423       // Validate inputs of merge
1424       for (uint i = 1; i < merge->req(); i++) {
1425         if (merge->in(i) != nullptr && !merge->in(i)->is_top() && !merge->in(i)->is_SafePointScalarObject()) {
1426           assert(false, "SafePointScalarMerge inputs should be null/top or SafePointScalarObject.");
1427           C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1428         }
1429       }
1430 
1431       // Validate users of merge
1432       for (DUIterator_Fast imax, i = merge->fast_outs(imax); i < imax; i++) {
1433         Node* sfpt = merge->fast_out(i);
1434         if (sfpt->is_SafePoint()) {
1435           int merge_idx = merge->merge_pointer_idx(sfpt->as_SafePoint()->jvms());
1436 
1437           if (sfpt->in(merge_idx) != nullptr && sfpt->in(merge_idx)->is_SafePointScalarMerge()) {
1438             assert(false, "SafePointScalarMerge nodes can't be nested.");
1439             C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1440           }
1441         } else {
1442           assert(false, "Only safepoints can use SafePointScalarMerge nodes.");
1443           C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1444         }
1445       }
1446     }
1447 
1448     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1449       Node* m = n->fast_out(i);
1450       ideal_nodes.push(m);
1451     }
1452   }
1453 }
1454 
1455 // Returns true if there is an object in the scope of sfn that does not escape globally.
1456 bool ConnectionGraph::has_ea_local_in_scope(SafePointNode* sfn) {
1457   Compile* C = _compile;
1458   for (JVMState* jvms = sfn->jvms(); jvms != nullptr; jvms = jvms->caller()) {
1459     if (C->env()->should_retain_local_variables() || C->env()->jvmti_can_walk_any_space() ||
1460         DeoptimizeObjectsALot) {
1461       // Jvmti agents can access locals. Must provide info about local objects at runtime.
1462       int num_locs = jvms->loc_size();
1463       for (int idx = 0; idx < num_locs; idx++) {
1464         Node* l = sfn->local(jvms, idx);
1465         if (not_global_escape(l)) {
1466           return true;
1467         }
1468       }
1469     }
1470     if (C->env()->jvmti_can_get_owned_monitor_info() ||
1471         C->env()->jvmti_can_walk_any_space() || DeoptimizeObjectsALot) {
1472       // Jvmti agents can read monitors. Must provide info about locked objects at runtime.
1473       int num_mon = jvms->nof_monitors();
1474       for (int idx = 0; idx < num_mon; idx++) {
1475         Node* m = sfn->monitor_obj(jvms, idx);
1476         if (m != nullptr && not_global_escape(m)) {
1477           return true;
1478         }
1479       }
1480     }
1481   }
1482   return false;
1483 }
1484 
1485 // Returns true if at least one of the arguments to the call is an object
1486 // that does not escape globally.
1487 bool ConnectionGraph::has_arg_escape(CallJavaNode* call) {
1488   if (call->method() != nullptr) {
1489     uint max_idx = TypeFunc::Parms + call->method()->arg_size();
1490     for (uint idx = TypeFunc::Parms; idx < max_idx; idx++) {
1491       Node* p = call->in(idx);
1492       if (not_global_escape(p)) {
1493         return true;
1494       }
1495     }
1496   } else {
1497     const char* name = call->as_CallStaticJava()->_name;
1498     assert(name != nullptr, "no name");
1499     // no arg escapes through uncommon traps
1500     if (strcmp(name, "uncommon_trap") != 0) {
1501       // process_call_arguments() assumes that all arguments escape globally
1502       const TypeTuple* d = call->tf()->domain_sig();
1503       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1504         const Type* at = d->field_at(i);
1505         if (at->isa_oopptr() != nullptr) {
1506           return true;
1507         }
1508       }
1509     }
1510   }
1511   return false;
1512 }
1513 
1514 
1515 
1516 // Utility function for nodes that load an object
1517 void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
1518   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1519   // ThreadLocal has RawPtr type.
1520   const Type* t = _igvn->type(n);
1521   if (t->make_ptr() != nullptr) {
1522     Node* adr = n->in(MemNode::Address);
1523 #ifdef ASSERT
1524     if (!adr->is_AddP()) {
1525       assert(_igvn->type(adr)->isa_rawptr(), "sanity");
1526     } else {
1527       assert((ptnode_adr(adr->_idx) == nullptr ||
1528               ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
1529     }
1530 #endif
1531     add_local_var_and_edge(n, PointsToNode::NoEscape,
1532                            adr, delayed_worklist);
1533   }
1534 }
1535 
1536 // Populate Connection Graph with PointsTo nodes and create simple
1537 // connection graph edges.
1538 void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
1539   assert(!_verify, "this method should not be called for verification");
1540   PhaseGVN* igvn = _igvn;
1541   uint n_idx = n->_idx;
1542   PointsToNode* n_ptn = ptnode_adr(n_idx);
1543   if (n_ptn != nullptr) {
1544     return; // No need to redefine PointsTo node during first iteration.
1545   }
1546   int opcode = n->Opcode();
1547   bool gc_handled = BarrierSet::barrier_set()->barrier_set_c2()->escape_add_to_con_graph(this, igvn, delayed_worklist, n, opcode);
1548   if (gc_handled) {
1549     return; // Ignore node if already handled by GC.
1550   }
1551 
1552   if (n->is_Call()) {
1553     // Arguments to allocation and locking don't escape.
1554     if (n->is_AbstractLock()) {
1555       // Put Lock and Unlock nodes on IGVN worklist to process them during
1556       // first IGVN optimization when escape information is still available.
1557       record_for_optimizer(n);
1558     } else if (n->is_Allocate()) {
1559       add_call_node(n->as_Call());
1560       record_for_optimizer(n);
1561     } else {
1562       if (n->is_CallStaticJava()) {
1563         const char* name = n->as_CallStaticJava()->_name;
1564         if (name != nullptr && strcmp(name, "uncommon_trap") == 0) {
1565           return; // Skip uncommon traps
1566         }
1567       }
1568       // Don't mark as processed since call's arguments have to be processed.
1569       delayed_worklist->push(n);
1570       // Check if a call returns an object.
1571       if ((n->as_Call()->returns_pointer() &&
1572            n->as_Call()->proj_out_or_null(TypeFunc::Parms) != nullptr) ||
1573           (n->is_CallStaticJava() &&
1574            n->as_CallStaticJava()->is_boxing_method())) {
1575         add_call_node(n->as_Call());
1576       } else if (n->as_Call()->tf()->returns_inline_type_as_fields()) {
1577         bool returns_oop = false;
1578         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax && !returns_oop; i++) {
1579           ProjNode* pn = n->fast_out(i)->as_Proj();
1580           if (pn->_con >= TypeFunc::Parms && pn->bottom_type()->isa_ptr()) {
1581             returns_oop = true;
1582           }
1583         }
1584         if (returns_oop) {
1585           add_call_node(n->as_Call());
1586         }
1587       }
1588     }
1589     return;
1590   }
1591   // Put this check here to process call arguments since some call nodes
1592   // point to phantom_obj.
1593   if (n_ptn == phantom_obj || n_ptn == null_obj) {
1594     return; // Skip predefined nodes.
1595   }
1596   switch (opcode) {
1597     case Op_AddP: {
1598       Node* base = get_addp_base(n);
1599       PointsToNode* ptn_base = ptnode_adr(base->_idx);
1600       // Field nodes are created for all field types. They are used in
1601       // adjust_scalar_replaceable_state() and split_unique_types().
1602       // Note, non-oop fields will have only base edges in Connection
1603       // Graph because such fields are not used for oop loads and stores.
1604       int offset = address_offset(n, igvn);
1605       add_field(n, PointsToNode::NoEscape, offset);
1606       if (ptn_base == nullptr) {
1607         delayed_worklist->push(n); // Process it later.
1608       } else {
1609         n_ptn = ptnode_adr(n_idx);
1610         add_base(n_ptn->as_Field(), ptn_base);
1611       }
1612       break;
1613     }
1614     case Op_CastX2P:
1615     case Op_CastI2N: {
1616       map_ideal_node(n, phantom_obj);
1617       break;
1618     }
1619     case Op_InlineType:
1620     case Op_CastPP:
1621     case Op_CheckCastPP:
1622     case Op_EncodeP:
1623     case Op_DecodeN:
1624     case Op_EncodePKlass:
1625     case Op_DecodeNKlass: {
1626       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), delayed_worklist);
1627       break;
1628     }
1629     case Op_CMoveP: {
1630       add_local_var(n, PointsToNode::NoEscape);
1631       // Do not add edges during first iteration because some could be
1632       // not defined yet.
1633       delayed_worklist->push(n);
1634       break;
1635     }
1636     case Op_ConP:
1637     case Op_ConN:
1638     case Op_ConNKlass: {
1639       // assume all oop constants globally escape except for null
1640       PointsToNode::EscapeState es;
1641       const Type* t = igvn->type(n);
1642       if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
1643         es = PointsToNode::NoEscape;
1644       } else {
1645         es = PointsToNode::GlobalEscape;
1646       }
1647       PointsToNode* ptn_con = add_java_object(n, es);
1648       set_not_scalar_replaceable(ptn_con NOT_PRODUCT(COMMA "Constant pointer"));
1649       break;
1650     }
1651     case Op_CreateEx: {
1652       // assume that all exception objects globally escape
1653       map_ideal_node(n, phantom_obj);
1654       break;
1655     }
1656     case Op_LoadKlass:
1657     case Op_LoadNKlass: {
1658       // Unknown class is loaded
1659       map_ideal_node(n, phantom_obj);
1660       break;
1661     }
1662     case Op_LoadP:
1663     case Op_LoadN: {
1664       add_objload_to_connection_graph(n, delayed_worklist);
1665       break;
1666     }
1667     case Op_Parm: {
1668       map_ideal_node(n, phantom_obj);
1669       break;
1670     }
1671     case Op_PartialSubtypeCheck: {
1672       // Produces Null or notNull and is used in only in CmpP so
1673       // phantom_obj could be used.
1674       map_ideal_node(n, phantom_obj); // Result is unknown
1675       break;
1676     }
1677     case Op_Phi: {
1678       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1679       // ThreadLocal has RawPtr type.
1680       const Type* t = n->as_Phi()->type();
1681       if (t->make_ptr() != nullptr) {
1682         add_local_var(n, PointsToNode::NoEscape);
1683         // Do not add edges during first iteration because some could be
1684         // not defined yet.
1685         delayed_worklist->push(n);
1686       }
1687       break;
1688     }
1689     case Op_LoadFlat:
1690       // Treat LoadFlat similar to an unknown call that receives nothing and produces its results
1691       map_ideal_node(n, phantom_obj);
1692       break;
1693     case Op_StoreFlat:
1694       // Treat StoreFlat similar to a call that escapes the stored flattened fields
1695       delayed_worklist->push(n);
1696       break;
1697     case Op_Proj: {
1698       // we are only interested in the oop result projection from a call
1699       if (n->as_Proj()->_con >= TypeFunc::Parms && n->in(0)->is_Call() &&
1700           (n->in(0)->as_Call()->returns_pointer() || n->bottom_type()->isa_ptr())) {
1701         assert((n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->as_Call()->returns_pointer()) ||
1702                n->in(0)->as_Call()->tf()->returns_inline_type_as_fields(), "what kind of oop return is it?");
1703         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), delayed_worklist);
1704       } else if (n->as_Proj()->_con >= TypeFunc::Parms && n->in(0)->is_LoadFlat() && igvn->type(n)->isa_ptr()) {
1705         // Treat LoadFlat outputs similar to a call return value
1706         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), delayed_worklist);
1707       }
1708       break;
1709     }
1710     case Op_Rethrow: // Exception object escapes
1711     case Op_Return: {
1712       if (n->req() > TypeFunc::Parms &&
1713           igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
1714         // Treat Return value as LocalVar with GlobalEscape escape state.
1715         add_local_var_and_edge(n, PointsToNode::GlobalEscape, n->in(TypeFunc::Parms), delayed_worklist);
1716       }
1717       break;
1718     }
1719     case Op_CompareAndExchangeP:
1720     case Op_CompareAndExchangeN:
1721     case Op_GetAndSetP:
1722     case Op_GetAndSetN: {
1723       add_objload_to_connection_graph(n, delayed_worklist);
1724       // fall-through
1725     }
1726     case Op_StoreP:
1727     case Op_StoreN:
1728     case Op_StoreNKlass:
1729     case Op_WeakCompareAndSwapP:
1730     case Op_WeakCompareAndSwapN:
1731     case Op_CompareAndSwapP:
1732     case Op_CompareAndSwapN: {
1733       add_to_congraph_unsafe_access(n, opcode, delayed_worklist);
1734       break;
1735     }
1736     case Op_AryEq:
1737     case Op_CountPositives:
1738     case Op_StrComp:
1739     case Op_StrEquals:
1740     case Op_StrIndexOf:
1741     case Op_StrIndexOfChar:
1742     case Op_StrInflatedCopy:
1743     case Op_StrCompressedCopy:
1744     case Op_VectorizedHashCode:
1745     case Op_EncodeISOArray: {
1746       add_local_var(n, PointsToNode::ArgEscape);
1747       delayed_worklist->push(n); // Process it later.
1748       break;
1749     }
1750     case Op_ThreadLocal: {
1751       PointsToNode* ptn_thr = add_java_object(n, PointsToNode::ArgEscape);
1752       set_not_scalar_replaceable(ptn_thr NOT_PRODUCT(COMMA "Constant pointer"));
1753       break;
1754     }
1755     case Op_Blackhole: {
1756       // All blackhole pointer arguments are globally escaping.
1757       // Only do this if there is at least one pointer argument.
1758       // Do not add edges during first iteration because some could be
1759       // not defined yet, defer to final step.
1760       for (uint i = 0; i < n->req(); i++) {
1761         Node* in = n->in(i);
1762         if (in != nullptr) {
1763           const Type* at = _igvn->type(in);
1764           if (!at->isa_ptr()) continue;
1765 
1766           add_local_var(n, PointsToNode::GlobalEscape);
1767           delayed_worklist->push(n);
1768           break;
1769         }
1770       }
1771       break;
1772     }
1773     default:
1774       ; // Do nothing for nodes not related to EA.
1775   }
1776   return;
1777 }
1778 
1779 // Add final simple edges to graph.
1780 void ConnectionGraph::add_final_edges(Node *n) {
1781   PointsToNode* n_ptn = ptnode_adr(n->_idx);
1782 #ifdef ASSERT
1783   if (_verify && n_ptn->is_JavaObject())
1784     return; // This method does not change graph for JavaObject.
1785 #endif
1786 
1787   if (n->is_Call()) {
1788     process_call_arguments(n->as_Call());
1789     return;
1790   }
1791   assert(n->is_Store() || n->is_LoadStore() || n->is_StoreFlat() ||
1792          ((n_ptn != nullptr) && (n_ptn->ideal_node() != nullptr)),
1793          "node should be registered already");
1794   int opcode = n->Opcode();
1795   bool gc_handled = BarrierSet::barrier_set()->barrier_set_c2()->escape_add_final_edges(this, _igvn, n, opcode);
1796   if (gc_handled) {
1797     return; // Ignore node if already handled by GC.
1798   }
1799   switch (opcode) {
1800     case Op_AddP: {
1801       Node* base = get_addp_base(n);
1802       PointsToNode* ptn_base = ptnode_adr(base->_idx);
1803       assert(ptn_base != nullptr, "field's base should be registered");
1804       add_base(n_ptn->as_Field(), ptn_base);
1805       break;
1806     }
1807     case Op_InlineType:
1808     case Op_CastPP:
1809     case Op_CheckCastPP:
1810     case Op_EncodeP:
1811     case Op_DecodeN:
1812     case Op_EncodePKlass:
1813     case Op_DecodeNKlass: {
1814       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), nullptr);
1815       break;
1816     }
1817     case Op_CMoveP: {
1818       for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
1819         Node* in = n->in(i);
1820         if (in == nullptr) {
1821           continue;  // ignore null
1822         }
1823         Node* uncast_in = in->uncast();
1824         if (uncast_in->is_top() || uncast_in == n) {
1825           continue;  // ignore top or inputs which go back this node
1826         }
1827         PointsToNode* ptn = ptnode_adr(in->_idx);
1828         assert(ptn != nullptr, "node should be registered");
1829         add_edge(n_ptn, ptn);
1830       }
1831       break;
1832     }
1833     case Op_LoadP:
1834     case Op_LoadN: {
1835       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1836       // ThreadLocal has RawPtr type.
1837       assert(_igvn->type(n)->make_ptr() != nullptr, "Unexpected node type");
1838       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(MemNode::Address), nullptr);
1839       break;
1840     }
1841     case Op_Phi: {
1842       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1843       // ThreadLocal has RawPtr type.
1844       assert(n->as_Phi()->type()->make_ptr() != nullptr, "Unexpected node type");
1845       for (uint i = 1; i < n->req(); i++) {
1846         Node* in = n->in(i);
1847         if (in == nullptr) {
1848           continue;  // ignore null
1849         }
1850         Node* uncast_in = in->uncast();
1851         if (uncast_in->is_top() || uncast_in == n) {
1852           continue;  // ignore top or inputs which go back this node
1853         }
1854         PointsToNode* ptn = ptnode_adr(in->_idx);
1855         assert(ptn != nullptr, "node should be registered");
1856         add_edge(n_ptn, ptn);
1857       }
1858       break;
1859     }
1860     case Op_StoreFlat: {
1861       // StoreFlat globally escapes its stored flattened fields
1862       InlineTypeNode* value = n->as_StoreFlat()->value();
1863       ciInlineKlass* vk = _igvn->type(value)->inline_klass();
1864       for (int i = 0; i < vk->nof_nonstatic_fields(); i++) {
1865         ciField* field = vk->nonstatic_field_at(i);
1866         if (field->type()->is_primitive_type()) {
1867           continue;
1868         }
1869 
1870         Node* field_value = value->field_value_by_offset(field->offset_in_bytes(), true);
1871         PointsToNode* field_value_ptn = ptnode_adr(field_value->_idx);
1872         set_escape_state(field_value_ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA "store into a flat field"));
1873       }
1874       break;
1875     }
1876     case Op_Proj: {
1877       if (n->in(0)->is_Call()) {
1878         // we are only interested in the oop result projection from a call
1879         assert((n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->as_Call()->returns_pointer()) ||
1880               n->in(0)->as_Call()->tf()->returns_inline_type_as_fields(), "what kind of oop return is it?");
1881         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), nullptr);
1882       } else if (n->in(0)->is_LoadFlat()) {
1883         // Treat LoadFlat outputs similar to a call return value
1884         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), nullptr);
1885       }
1886       break;
1887     }
1888     case Op_Rethrow: // Exception object escapes
1889     case Op_Return: {
1890       assert(n->req() > TypeFunc::Parms && _igvn->type(n->in(TypeFunc::Parms))->isa_oopptr(),
1891              "Unexpected node type");
1892       // Treat Return value as LocalVar with GlobalEscape escape state.
1893       add_local_var_and_edge(n, PointsToNode::GlobalEscape, n->in(TypeFunc::Parms), nullptr);
1894       break;
1895     }
1896     case Op_CompareAndExchangeP:
1897     case Op_CompareAndExchangeN:
1898     case Op_GetAndSetP:
1899     case Op_GetAndSetN:{
1900       assert(_igvn->type(n)->make_ptr() != nullptr, "Unexpected node type");
1901       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(MemNode::Address), nullptr);
1902       // fall-through
1903     }
1904     case Op_CompareAndSwapP:
1905     case Op_CompareAndSwapN:
1906     case Op_WeakCompareAndSwapP:
1907     case Op_WeakCompareAndSwapN:
1908     case Op_StoreP:
1909     case Op_StoreN:
1910     case Op_StoreNKlass:{
1911       add_final_edges_unsafe_access(n, opcode);
1912       break;
1913     }
1914     case Op_VectorizedHashCode:
1915     case Op_AryEq:
1916     case Op_CountPositives:
1917     case Op_StrComp:
1918     case Op_StrEquals:
1919     case Op_StrIndexOf:
1920     case Op_StrIndexOfChar:
1921     case Op_StrInflatedCopy:
1922     case Op_StrCompressedCopy:
1923     case Op_EncodeISOArray: {
1924       // char[]/byte[] arrays passed to string intrinsic do not escape but
1925       // they are not scalar replaceable. Adjust escape state for them.
1926       // Start from in(2) edge since in(1) is memory edge.
1927       for (uint i = 2; i < n->req(); i++) {
1928         Node* adr = n->in(i);
1929         const Type* at = _igvn->type(adr);
1930         if (!adr->is_top() && at->isa_ptr()) {
1931           assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
1932                  at->isa_ptr() != nullptr, "expecting a pointer");
1933           if (adr->is_AddP()) {
1934             adr = get_addp_base(adr);
1935           }
1936           PointsToNode* ptn = ptnode_adr(adr->_idx);
1937           assert(ptn != nullptr, "node should be registered");
1938           add_edge(n_ptn, ptn);
1939         }
1940       }
1941       break;
1942     }
1943     case Op_Blackhole: {
1944       // All blackhole pointer arguments are globally escaping.
1945       for (uint i = 0; i < n->req(); i++) {
1946         Node* in = n->in(i);
1947         if (in != nullptr) {
1948           const Type* at = _igvn->type(in);
1949           if (!at->isa_ptr()) continue;
1950 
1951           if (in->is_AddP()) {
1952             in = get_addp_base(in);
1953           }
1954 
1955           PointsToNode* ptn = ptnode_adr(in->_idx);
1956           assert(ptn != nullptr, "should be defined already");
1957           set_escape_state(ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA "blackhole"));
1958           add_edge(n_ptn, ptn);
1959         }
1960       }
1961       break;
1962     }
1963     default: {
1964       // This method should be called only for EA specific nodes which may
1965       // miss some edges when they were created.
1966 #ifdef ASSERT
1967       n->dump(1);
1968 #endif
1969       guarantee(false, "unknown node");
1970     }
1971   }
1972   return;
1973 }
1974 
1975 void ConnectionGraph::add_to_congraph_unsafe_access(Node* n, uint opcode, Unique_Node_List* delayed_worklist) {
1976   Node* adr = n->in(MemNode::Address);
1977   const Type* adr_type = _igvn->type(adr);
1978   adr_type = adr_type->make_ptr();
1979   if (adr_type == nullptr) {
1980     return; // skip dead nodes
1981   }
1982   if (adr_type->isa_oopptr()
1983       || ((opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass)
1984           && adr_type == TypeRawPtr::NOTNULL
1985           && is_captured_store_address(adr))) {
1986     delayed_worklist->push(n); // Process it later.
1987 #ifdef ASSERT
1988     assert (adr->is_AddP(), "expecting an AddP");
1989     if (adr_type == TypeRawPtr::NOTNULL) {
1990       // Verify a raw address for a store captured by Initialize node.
1991       int offs = (int) _igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
1992       assert(offs != Type::OffsetBot, "offset must be a constant");
1993     }
1994 #endif
1995   } else {
1996     // Ignore copy the displaced header to the BoxNode (OSR compilation).
1997     if (adr->is_BoxLock()) {
1998       return;
1999     }
2000     // Stored value escapes in unsafe access.
2001     if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
2002       delayed_worklist->push(n); // Process unsafe access later.
2003       return;
2004     }
2005 #ifdef ASSERT
2006     n->dump(1);
2007     assert(false, "not unsafe");
2008 #endif
2009   }
2010 }
2011 
2012 bool ConnectionGraph::add_final_edges_unsafe_access(Node* n, uint opcode) {
2013   Node* adr = n->in(MemNode::Address);
2014   const Type *adr_type = _igvn->type(adr);
2015   adr_type = adr_type->make_ptr();
2016 #ifdef ASSERT
2017   if (adr_type == nullptr) {
2018     n->dump(1);
2019     assert(adr_type != nullptr, "dead node should not be on list");
2020     return true;
2021   }
2022 #endif
2023 
2024   if (adr_type->isa_oopptr()
2025       || ((opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass)
2026            && adr_type == TypeRawPtr::NOTNULL
2027            && is_captured_store_address(adr))) {
2028     // Point Address to Value
2029     PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
2030     assert(adr_ptn != nullptr &&
2031            adr_ptn->as_Field()->is_oop(), "node should be registered");
2032     Node* val = n->in(MemNode::ValueIn);
2033     PointsToNode* ptn = ptnode_adr(val->_idx);
2034     assert(ptn != nullptr, "node should be registered");
2035     add_edge(adr_ptn, ptn);
2036     return true;
2037   } else if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
2038     // Stored value escapes in unsafe access.
2039     Node* val = n->in(MemNode::ValueIn);
2040     PointsToNode* ptn = ptnode_adr(val->_idx);
2041     assert(ptn != nullptr, "node should be registered");
2042     set_escape_state(ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA "stored at raw address"));
2043     // Add edge to object for unsafe access with offset.
2044     PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
2045     assert(adr_ptn != nullptr, "node should be registered");
2046     if (adr_ptn->is_Field()) {
2047       assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
2048       add_edge(adr_ptn, ptn);
2049     }
2050     return true;
2051   }
2052 #ifdef ASSERT
2053   n->dump(1);
2054   assert(false, "not unsafe");
2055 #endif
2056   return false;
2057 }
2058 
2059 void ConnectionGraph::add_call_node(CallNode* call) {
2060   assert(call->returns_pointer() || call->tf()->returns_inline_type_as_fields(), "only for call which returns pointer");
2061   uint call_idx = call->_idx;
2062   if (call->is_Allocate()) {
2063     Node* k = call->in(AllocateNode::KlassNode);
2064     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
2065     assert(kt != nullptr, "TypeKlassPtr  required.");
2066     PointsToNode::EscapeState es = PointsToNode::NoEscape;
2067     bool scalar_replaceable = true;
2068     NOT_PRODUCT(const char* nsr_reason = "");
2069     if (call->is_AllocateArray()) {
2070       if (!kt->isa_aryklassptr()) { // StressReflectiveCode
2071         es = PointsToNode::GlobalEscape;
2072       } else {
2073         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
2074         if (length < 0) {
2075           // Not scalar replaceable if the length is not constant.
2076           scalar_replaceable = false;
2077           NOT_PRODUCT(nsr_reason = "has a non-constant length");
2078         } else if (length > EliminateAllocationArraySizeLimit) {
2079           // Not scalar replaceable if the length is too big.
2080           scalar_replaceable = false;
2081           NOT_PRODUCT(nsr_reason = "has a length that is too big");
2082         }
2083       }
2084     } else {  // Allocate instance
2085       if (!kt->isa_instklassptr()) { // StressReflectiveCode
2086         es = PointsToNode::GlobalEscape;
2087       } else {
2088         const TypeInstKlassPtr* ikt = kt->is_instklassptr();
2089         ciInstanceKlass* ik = ikt->klass_is_exact() ? ikt->exact_klass()->as_instance_klass() : ikt->instance_klass();
2090         if (ik->is_subclass_of(_compile->env()->Thread_klass()) ||
2091             ik->is_subclass_of(_compile->env()->Reference_klass()) ||
2092             !ik->can_be_instantiated() ||
2093             ik->has_finalizer()) {
2094           es = PointsToNode::GlobalEscape;
2095         } else {
2096           int nfields = ik->as_instance_klass()->nof_nonstatic_fields();
2097           if (nfields > EliminateAllocationFieldsLimit) {
2098             // Not scalar replaceable if there are too many fields.
2099             scalar_replaceable = false;
2100             NOT_PRODUCT(nsr_reason = "has too many fields");
2101           }
2102         }
2103       }
2104     }
2105     add_java_object(call, es);
2106     PointsToNode* ptn = ptnode_adr(call_idx);
2107     if (!scalar_replaceable && ptn->scalar_replaceable()) {
2108       set_not_scalar_replaceable(ptn NOT_PRODUCT(COMMA nsr_reason));
2109     }
2110   } else if (call->is_CallStaticJava()) {
2111     // Call nodes could be different types:
2112     //
2113     // 1. CallDynamicJavaNode (what happened during call is unknown):
2114     //
2115     //    - mapped to GlobalEscape JavaObject node if oop is returned;
2116     //
2117     //    - all oop arguments are escaping globally;
2118     //
2119     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
2120     //
2121     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
2122     //
2123     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
2124     //    - mapped to NoEscape JavaObject node if non-escaping object allocated
2125     //      during call is returned;
2126     //    - mapped to ArgEscape LocalVar node pointed to object arguments
2127     //      which are returned and does not escape during call;
2128     //
2129     //    - oop arguments escaping status is defined by bytecode analysis;
2130     //
2131     // For a static call, we know exactly what method is being called.
2132     // Use bytecode estimator to record whether the call's return value escapes.
2133     ciMethod* meth = call->as_CallJava()->method();
2134     if (meth == nullptr) {
2135       const char* name = call->as_CallStaticJava()->_name;
2136       assert(strncmp(name, "C2 Runtime multianewarray", 25) == 0 ||
2137              strncmp(name, "C2 Runtime load_unknown_inline", 30) == 0 ||
2138              strncmp(name, "store_inline_type_fields_to_buf", 31) == 0, "TODO: add failed case check");
2139       // Returns a newly allocated non-escaped object.
2140       add_java_object(call, PointsToNode::NoEscape);
2141       set_not_scalar_replaceable(ptnode_adr(call_idx) NOT_PRODUCT(COMMA "is result of multinewarray"));
2142     } else if (meth->is_boxing_method()) {
2143       // Returns boxing object
2144       PointsToNode::EscapeState es;
2145       vmIntrinsics::ID intr = meth->intrinsic_id();
2146       if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
2147         // It does not escape if object is always allocated.
2148         es = PointsToNode::NoEscape;
2149       } else {
2150         // It escapes globally if object could be loaded from cache.
2151         es = PointsToNode::GlobalEscape;
2152       }
2153       add_java_object(call, es);
2154       if (es == PointsToNode::GlobalEscape) {
2155         set_not_scalar_replaceable(ptnode_adr(call->_idx) NOT_PRODUCT(COMMA "object can be loaded from boxing cache"));
2156       }
2157     } else {
2158       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
2159       call_analyzer->copy_dependencies(_compile->dependencies());
2160       if (call_analyzer->is_return_allocated()) {
2161         // Returns a newly allocated non-escaped object, simply
2162         // update dependency information.
2163         // Mark it as NoEscape so that objects referenced by
2164         // it's fields will be marked as NoEscape at least.
2165         add_java_object(call, PointsToNode::NoEscape);
2166         set_not_scalar_replaceable(ptnode_adr(call_idx) NOT_PRODUCT(COMMA "is result of call"));
2167       } else {
2168         // Determine whether any arguments are returned.
2169         const TypeTuple* d = call->tf()->domain_cc();
2170         bool ret_arg = false;
2171         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2172           if (d->field_at(i)->isa_ptr() != nullptr &&
2173               call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
2174             ret_arg = true;
2175             break;
2176           }
2177         }
2178         if (ret_arg) {
2179           add_local_var(call, PointsToNode::ArgEscape);
2180         } else {
2181           // Returns unknown object.
2182           map_ideal_node(call, phantom_obj);
2183         }
2184       }
2185     }
2186   } else {
2187     // An other type of call, assume the worst case:
2188     // returned value is unknown and globally escapes.
2189     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
2190     map_ideal_node(call, phantom_obj);
2191   }
2192 }
2193 
2194 void ConnectionGraph::process_call_arguments(CallNode *call) {
2195     bool is_arraycopy = false;
2196     switch (call->Opcode()) {
2197 #ifdef ASSERT
2198     case Op_Allocate:
2199     case Op_AllocateArray:
2200     case Op_Lock:
2201     case Op_Unlock:
2202       assert(false, "should be done already");
2203       break;
2204 #endif
2205     case Op_ArrayCopy:
2206     case Op_CallLeafNoFP:
2207       // Most array copies are ArrayCopy nodes at this point but there
2208       // are still a few direct calls to the copy subroutines (See
2209       // PhaseStringOpts::copy_string())
2210       is_arraycopy = (call->Opcode() == Op_ArrayCopy) ||
2211         call->as_CallLeaf()->is_call_to_arraycopystub();
2212       // fall through
2213     case Op_CallLeafVector:
2214     case Op_CallLeaf: {
2215       // Stub calls, objects do not escape but they are not scale replaceable.
2216       // Adjust escape state for outgoing arguments.
2217       const TypeTuple * d = call->tf()->domain_sig();
2218       bool src_has_oops = false;
2219       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2220         const Type* at = d->field_at(i);
2221         Node *arg = call->in(i);
2222         if (arg == nullptr) {
2223           continue;
2224         }
2225         const Type *aat = _igvn->type(arg);
2226         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr()) {
2227           continue;
2228         }
2229         if (arg->is_AddP()) {
2230           //
2231           // The inline_native_clone() case when the arraycopy stub is called
2232           // after the allocation before Initialize and CheckCastPP nodes.
2233           // Or normal arraycopy for object arrays case.
2234           //
2235           // Set AddP's base (Allocate) as not scalar replaceable since
2236           // pointer to the base (with offset) is passed as argument.
2237           //
2238           arg = get_addp_base(arg);
2239         }
2240         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
2241         assert(arg_ptn != nullptr, "should be registered");
2242         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
2243         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
2244           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
2245                  aat->isa_ptr() != nullptr, "expecting an Ptr");
2246           bool arg_has_oops = aat->isa_oopptr() &&
2247                               (aat->isa_instptr() ||
2248                                (aat->isa_aryptr() && (aat->isa_aryptr()->elem() == Type::BOTTOM || aat->isa_aryptr()->elem()->make_oopptr() != nullptr)) ||
2249                                (aat->isa_aryptr() && aat->isa_aryptr()->elem() != nullptr &&
2250                                                                aat->isa_aryptr()->is_flat() &&
2251                                                                aat->isa_aryptr()->elem()->inline_klass()->contains_oops()));
2252           if (i == TypeFunc::Parms) {
2253             src_has_oops = arg_has_oops;
2254           }
2255           //
2256           // src or dst could be j.l.Object when other is basic type array:
2257           //
2258           //   arraycopy(char[],0,Object*,0,size);
2259           //   arraycopy(Object*,0,char[],0,size);
2260           //
2261           // Don't add edges in such cases.
2262           //
2263           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
2264                                        arg_has_oops && (i > TypeFunc::Parms);
2265 #ifdef ASSERT
2266           if (!(is_arraycopy ||
2267                 BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(call) ||
2268                 (call->as_CallLeaf()->_name != nullptr &&
2269                  (strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
2270                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32C") == 0 ||
2271                   strcmp(call->as_CallLeaf()->_name, "updateBytesAdler32") == 0 ||
2272                   strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
2273                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
2274                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
2275                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
2276                   strcmp(call->as_CallLeaf()->_name, "electronicCodeBook_encryptAESCrypt") == 0 ||
2277                   strcmp(call->as_CallLeaf()->_name, "electronicCodeBook_decryptAESCrypt") == 0 ||
2278                   strcmp(call->as_CallLeaf()->_name, "counterMode_AESCrypt") == 0 ||
2279                   strcmp(call->as_CallLeaf()->_name, "galoisCounterMode_AESCrypt") == 0 ||
2280                   strcmp(call->as_CallLeaf()->_name, "poly1305_processBlocks") == 0 ||
2281                   strcmp(call->as_CallLeaf()->_name, "intpoly_montgomeryMult_P256") == 0 ||
2282                   strcmp(call->as_CallLeaf()->_name, "intpoly_assign") == 0 ||
2283                   strcmp(call->as_CallLeaf()->_name, "ghash_processBlocks") == 0 ||
2284                   strcmp(call->as_CallLeaf()->_name, "chacha20Block") == 0 ||
2285                   strcmp(call->as_CallLeaf()->_name, "kyberNtt") == 0 ||
2286                   strcmp(call->as_CallLeaf()->_name, "kyberInverseNtt") == 0 ||
2287                   strcmp(call->as_CallLeaf()->_name, "kyberNttMult") == 0 ||
2288                   strcmp(call->as_CallLeaf()->_name, "kyberAddPoly_2") == 0 ||
2289                   strcmp(call->as_CallLeaf()->_name, "kyberAddPoly_3") == 0 ||
2290                   strcmp(call->as_CallLeaf()->_name, "kyber12To16") == 0 ||
2291                   strcmp(call->as_CallLeaf()->_name, "kyberBarrettReduce") == 0 ||
2292                   strcmp(call->as_CallLeaf()->_name, "dilithiumAlmostNtt") == 0 ||
2293                   strcmp(call->as_CallLeaf()->_name, "dilithiumAlmostInverseNtt") == 0 ||
2294                   strcmp(call->as_CallLeaf()->_name, "dilithiumNttMult") == 0 ||
2295                   strcmp(call->as_CallLeaf()->_name, "dilithiumMontMulByConstant") == 0 ||
2296                   strcmp(call->as_CallLeaf()->_name, "dilithiumDecomposePoly") == 0 ||
2297                   strcmp(call->as_CallLeaf()->_name, "encodeBlock") == 0 ||
2298                   strcmp(call->as_CallLeaf()->_name, "decodeBlock") == 0 ||
2299                   strcmp(call->as_CallLeaf()->_name, "md5_implCompress") == 0 ||
2300                   strcmp(call->as_CallLeaf()->_name, "md5_implCompressMB") == 0 ||
2301                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
2302                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
2303                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
2304                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
2305                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
2306                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
2307                   strcmp(call->as_CallLeaf()->_name, "sha3_implCompress") == 0 ||
2308                   strcmp(call->as_CallLeaf()->_name, "double_keccak") == 0 ||
2309                   strcmp(call->as_CallLeaf()->_name, "sha3_implCompressMB") == 0 ||
2310                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
2311                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
2312                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0 ||
2313                   strcmp(call->as_CallLeaf()->_name, "montgomery_multiply") == 0 ||
2314                   strcmp(call->as_CallLeaf()->_name, "montgomery_square") == 0 ||
2315                   strcmp(call->as_CallLeaf()->_name, "vectorizedMismatch") == 0 ||
2316                   strcmp(call->as_CallLeaf()->_name, "load_unknown_inline") == 0 ||
2317                   strcmp(call->as_CallLeaf()->_name, "store_unknown_inline") == 0 ||
2318                   strcmp(call->as_CallLeaf()->_name, "store_inline_type_fields_to_buf") == 0 ||
2319                   strcmp(call->as_CallLeaf()->_name, "bigIntegerRightShiftWorker") == 0 ||
2320                   strcmp(call->as_CallLeaf()->_name, "bigIntegerLeftShiftWorker") == 0 ||
2321                   strcmp(call->as_CallLeaf()->_name, "vectorizedMismatch") == 0 ||
2322                   strcmp(call->as_CallLeaf()->_name, "stringIndexOf") == 0 ||
2323                   strcmp(call->as_CallLeaf()->_name, "arraysort_stub") == 0 ||
2324                   strcmp(call->as_CallLeaf()->_name, "array_partition_stub") == 0 ||
2325                   strcmp(call->as_CallLeaf()->_name, "get_class_id_intrinsic") == 0 ||
2326                   strcmp(call->as_CallLeaf()->_name, "unsafe_setmemory") == 0)
2327                  ))) {
2328             call->dump();
2329             fatal("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name);
2330           }
2331 #endif
2332           // Always process arraycopy's destination object since
2333           // we need to add all possible edges to references in
2334           // source object.
2335           if (arg_esc >= PointsToNode::ArgEscape &&
2336               !arg_is_arraycopy_dest) {
2337             continue;
2338           }
2339           PointsToNode::EscapeState es = PointsToNode::ArgEscape;
2340           if (call->is_ArrayCopy()) {
2341             ArrayCopyNode* ac = call->as_ArrayCopy();
2342             if (ac->is_clonebasic() ||
2343                 ac->is_arraycopy_validated() ||
2344                 ac->is_copyof_validated() ||
2345                 ac->is_copyofrange_validated()) {
2346               es = PointsToNode::NoEscape;
2347             }
2348           }
2349           set_escape_state(arg_ptn, es NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2350           if (arg_is_arraycopy_dest) {
2351             Node* src = call->in(TypeFunc::Parms);
2352             if (src->is_AddP()) {
2353               src = get_addp_base(src);
2354             }
2355             PointsToNode* src_ptn = ptnode_adr(src->_idx);
2356             assert(src_ptn != nullptr, "should be registered");
2357             // Special arraycopy edge:
2358             // Only escape state of destination object's fields affects
2359             // escape state of fields in source object.
2360             add_arraycopy(call, es, src_ptn, arg_ptn);
2361           }
2362         }
2363       }
2364       break;
2365     }
2366     case Op_CallStaticJava: {
2367       // For a static call, we know exactly what method is being called.
2368       // Use bytecode estimator to record the call's escape affects
2369 #ifdef ASSERT
2370       const char* name = call->as_CallStaticJava()->_name;
2371       assert((name == nullptr || strcmp(name, "uncommon_trap") != 0), "normal calls only");
2372 #endif
2373       ciMethod* meth = call->as_CallJava()->method();
2374       if ((meth != nullptr) && meth->is_boxing_method()) {
2375         break; // Boxing methods do not modify any oops.
2376       }
2377       BCEscapeAnalyzer* call_analyzer = (meth !=nullptr) ? meth->get_bcea() : nullptr;
2378       // fall-through if not a Java method or no analyzer information
2379       if (call_analyzer != nullptr) {
2380         PointsToNode* call_ptn = ptnode_adr(call->_idx);
2381         const TypeTuple* d = call->tf()->domain_cc();
2382         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2383           const Type* at = d->field_at(i);
2384           int k = i - TypeFunc::Parms;
2385           Node* arg = call->in(i);
2386           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
2387           if (at->isa_ptr() != nullptr &&
2388               call_analyzer->is_arg_returned(k)) {
2389             // The call returns arguments.
2390             if (call_ptn != nullptr) { // Is call's result used?
2391               assert(call_ptn->is_LocalVar(), "node should be registered");
2392               assert(arg_ptn != nullptr, "node should be registered");
2393               add_edge(call_ptn, arg_ptn);
2394             }
2395           }
2396           if (at->isa_oopptr() != nullptr &&
2397               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
2398             if (!call_analyzer->is_arg_stack(k)) {
2399               // The argument global escapes
2400               set_escape_state(arg_ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2401             } else {
2402               set_escape_state(arg_ptn, PointsToNode::ArgEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2403               if (!call_analyzer->is_arg_local(k)) {
2404                 // The argument itself doesn't escape, but any fields might
2405                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2406               }
2407             }
2408           }
2409         }
2410         if (call_ptn != nullptr && call_ptn->is_LocalVar()) {
2411           // The call returns arguments.
2412           assert(call_ptn->edge_count() > 0, "sanity");
2413           if (!call_analyzer->is_return_local()) {
2414             // Returns also unknown object.
2415             add_edge(call_ptn, phantom_obj);
2416           }
2417         }
2418         break;
2419       }
2420     }
2421     default: {
2422       // Fall-through here if not a Java method or no analyzer information
2423       // or some other type of call, assume the worst case: all arguments
2424       // globally escape.
2425       const TypeTuple* d = call->tf()->domain_cc();
2426       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2427         const Type* at = d->field_at(i);
2428         if (at->isa_oopptr() != nullptr) {
2429           Node* arg = call->in(i);
2430           if (arg->is_AddP()) {
2431             arg = get_addp_base(arg);
2432           }
2433           assert(ptnode_adr(arg->_idx) != nullptr, "should be defined already");
2434           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2435         }
2436       }
2437     }
2438   }
2439 }
2440 
2441 
2442 // Finish Graph construction.
2443 bool ConnectionGraph::complete_connection_graph(
2444                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
2445                          GrowableArray<JavaObjectNode*>& non_escaped_allocs_worklist,
2446                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
2447                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
2448   // Normally only 1-3 passes needed to build Connection Graph depending
2449   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
2450   // Set limit to 20 to catch situation when something did go wrong and
2451   // bailout Escape Analysis.
2452   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
2453 #define GRAPH_BUILD_ITER_LIMIT 20
2454 
2455   // Propagate GlobalEscape and ArgEscape escape states and check that
2456   // we still have non-escaping objects. The method pushs on _worklist
2457   // Field nodes which reference phantom_object.
2458   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_allocs_worklist)) {
2459     return false; // Nothing to do.
2460   }
2461   // Now propagate references to all JavaObject nodes.
2462   int java_objects_length = java_objects_worklist.length();
2463   elapsedTimer build_time;
2464   build_time.start();
2465   elapsedTimer time;
2466   bool timeout = false;
2467   int new_edges = 1;
2468   int iterations = 0;
2469   do {
2470     while ((new_edges > 0) &&
2471            (iterations++ < GRAPH_BUILD_ITER_LIMIT)) {
2472       double start_time = time.seconds();
2473       time.start();
2474       new_edges = 0;
2475       // Propagate references to phantom_object for nodes pushed on _worklist
2476       // by find_non_escaped_objects() and find_field_value().
2477       new_edges += add_java_object_edges(phantom_obj, false);
2478       for (int next = 0; next < java_objects_length; ++next) {
2479         JavaObjectNode* ptn = java_objects_worklist.at(next);
2480         new_edges += add_java_object_edges(ptn, true);
2481 
2482 #define SAMPLE_SIZE 4
2483         if ((next % SAMPLE_SIZE) == 0) {
2484           // Each 4 iterations calculate how much time it will take
2485           // to complete graph construction.
2486           time.stop();
2487           // Poll for requests from shutdown mechanism to quiesce compiler
2488           // because Connection graph construction may take long time.
2489           CompileBroker::maybe_block();
2490           double stop_time = time.seconds();
2491           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
2492           double time_until_end = time_per_iter * (double)(java_objects_length - next);
2493           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
2494             timeout = true;
2495             break; // Timeout
2496           }
2497           start_time = stop_time;
2498           time.start();
2499         }
2500 #undef SAMPLE_SIZE
2501 
2502       }
2503       if (timeout) break;
2504       if (new_edges > 0) {
2505         // Update escape states on each iteration if graph was updated.
2506         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_allocs_worklist)) {
2507           return false; // Nothing to do.
2508         }
2509       }
2510       time.stop();
2511       if (time.seconds() >= EscapeAnalysisTimeout) {
2512         timeout = true;
2513         break;
2514       }
2515     }
2516     if ((iterations < GRAPH_BUILD_ITER_LIMIT) && !timeout) {
2517       time.start();
2518       // Find fields which have unknown value.
2519       int fields_length = oop_fields_worklist.length();
2520       for (int next = 0; next < fields_length; next++) {
2521         FieldNode* field = oop_fields_worklist.at(next);
2522         if (field->edge_count() == 0) {
2523           new_edges += find_field_value(field);
2524           // This code may added new edges to phantom_object.
2525           // Need an other cycle to propagate references to phantom_object.
2526         }
2527       }
2528       time.stop();
2529       if (time.seconds() >= EscapeAnalysisTimeout) {
2530         timeout = true;
2531         break;
2532       }
2533     } else {
2534       new_edges = 0; // Bailout
2535     }
2536   } while (new_edges > 0);
2537 
2538   build_time.stop();
2539   _build_time = build_time.seconds();
2540   _build_iterations = iterations;
2541 
2542   // Bailout if passed limits.
2543   if ((iterations >= GRAPH_BUILD_ITER_LIMIT) || timeout) {
2544     Compile* C = _compile;
2545     if (C->log() != nullptr) {
2546       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
2547       C->log()->text("%s", timeout ? "time" : "iterations");
2548       C->log()->end_elem(" limit'");
2549     }
2550     assert(ExitEscapeAnalysisOnTimeout, "infinite EA connection graph build during invocation %d (%f sec, %d iterations) with %d nodes and worklist size %d",
2551            _invocation, _build_time, _build_iterations, nodes_size(), ptnodes_worklist.length());
2552     // Possible infinite build_connection_graph loop,
2553     // bailout (no changes to ideal graph were made).
2554     return false;
2555   }
2556 
2557 #undef GRAPH_BUILD_ITER_LIMIT
2558 
2559   // Find fields initialized by null for non-escaping Allocations.
2560   int non_escaped_length = non_escaped_allocs_worklist.length();
2561   for (int next = 0; next < non_escaped_length; next++) {
2562     JavaObjectNode* ptn = non_escaped_allocs_worklist.at(next);
2563     PointsToNode::EscapeState es = ptn->escape_state();
2564     assert(es <= PointsToNode::ArgEscape, "sanity");
2565     if (es == PointsToNode::NoEscape) {
2566       if (find_init_values_null(ptn, _igvn) > 0) {
2567         // Adding references to null object does not change escape states
2568         // since it does not escape. Also no fields are added to null object.
2569         add_java_object_edges(null_obj, false);
2570       }
2571     }
2572     Node* n = ptn->ideal_node();
2573     if (n->is_Allocate()) {
2574       // The object allocated by this Allocate node will never be
2575       // seen by an other thread. Mark it so that when it is
2576       // expanded no MemBarStoreStore is added.
2577       InitializeNode* ini = n->as_Allocate()->initialization();
2578       if (ini != nullptr)
2579         ini->set_does_not_escape();
2580     }
2581   }
2582   return true; // Finished graph construction.
2583 }
2584 
2585 // Propagate GlobalEscape and ArgEscape escape states to all nodes
2586 // and check that we still have non-escaping java objects.
2587 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
2588                                                GrowableArray<JavaObjectNode*>& non_escaped_allocs_worklist) {
2589   GrowableArray<PointsToNode*> escape_worklist;
2590   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
2591   int ptnodes_length = ptnodes_worklist.length();
2592   for (int next = 0; next < ptnodes_length; ++next) {
2593     PointsToNode* ptn = ptnodes_worklist.at(next);
2594     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
2595         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
2596       escape_worklist.push(ptn);
2597     }
2598   }
2599   // Set escape states to referenced nodes (edges list).
2600   while (escape_worklist.length() > 0) {
2601     PointsToNode* ptn = escape_worklist.pop();
2602     PointsToNode::EscapeState es  = ptn->escape_state();
2603     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
2604     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
2605         es >= PointsToNode::ArgEscape) {
2606       // GlobalEscape or ArgEscape state of field means it has unknown value.
2607       if (add_edge(ptn, phantom_obj)) {
2608         // New edge was added
2609         add_field_uses_to_worklist(ptn->as_Field());
2610       }
2611     }
2612     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2613       PointsToNode* e = i.get();
2614       if (e->is_Arraycopy()) {
2615         assert(ptn->arraycopy_dst(), "sanity");
2616         // Propagate only fields escape state through arraycopy edge.
2617         if (e->fields_escape_state() < field_es) {
2618           set_fields_escape_state(e, field_es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2619           escape_worklist.push(e);
2620         }
2621       } else if (es >= field_es) {
2622         // fields_escape_state is also set to 'es' if it is less than 'es'.
2623         if (e->escape_state() < es) {
2624           set_escape_state(e, es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2625           escape_worklist.push(e);
2626         }
2627       } else {
2628         // Propagate field escape state.
2629         bool es_changed = false;
2630         if (e->fields_escape_state() < field_es) {
2631           set_fields_escape_state(e, field_es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2632           es_changed = true;
2633         }
2634         if ((e->escape_state() < field_es) &&
2635             e->is_Field() && ptn->is_JavaObject() &&
2636             e->as_Field()->is_oop()) {
2637           // Change escape state of referenced fields.
2638           set_escape_state(e, field_es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2639           es_changed = true;
2640         } else if (e->escape_state() < es) {
2641           set_escape_state(e, es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2642           es_changed = true;
2643         }
2644         if (es_changed) {
2645           escape_worklist.push(e);
2646         }
2647       }
2648     }
2649   }
2650   // Remove escaped objects from non_escaped list.
2651   for (int next = non_escaped_allocs_worklist.length()-1; next >= 0 ; --next) {
2652     JavaObjectNode* ptn = non_escaped_allocs_worklist.at(next);
2653     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
2654       non_escaped_allocs_worklist.delete_at(next);
2655     }
2656     if (ptn->escape_state() == PointsToNode::NoEscape) {
2657       // Find fields in non-escaped allocations which have unknown value.
2658       find_init_values_phantom(ptn);
2659     }
2660   }
2661   return (non_escaped_allocs_worklist.length() > 0);
2662 }
2663 
2664 // Add all references to JavaObject node by walking over all uses.
2665 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
2666   int new_edges = 0;
2667   if (populate_worklist) {
2668     // Populate _worklist by uses of jobj's uses.
2669     for (UseIterator i(jobj); i.has_next(); i.next()) {
2670       PointsToNode* use = i.get();
2671       if (use->is_Arraycopy()) {
2672         continue;
2673       }
2674       add_uses_to_worklist(use);
2675       if (use->is_Field() && use->as_Field()->is_oop()) {
2676         // Put on worklist all field's uses (loads) and
2677         // related field nodes (same base and offset).
2678         add_field_uses_to_worklist(use->as_Field());
2679       }
2680     }
2681   }
2682   for (int l = 0; l < _worklist.length(); l++) {
2683     PointsToNode* use = _worklist.at(l);
2684     if (PointsToNode::is_base_use(use)) {
2685       // Add reference from jobj to field and from field to jobj (field's base).
2686       use = PointsToNode::get_use_node(use)->as_Field();
2687       if (add_base(use->as_Field(), jobj)) {
2688         new_edges++;
2689       }
2690       continue;
2691     }
2692     assert(!use->is_JavaObject(), "sanity");
2693     if (use->is_Arraycopy()) {
2694       if (jobj == null_obj) { // null object does not have field edges
2695         continue;
2696       }
2697       // Added edge from Arraycopy node to arraycopy's source java object
2698       if (add_edge(use, jobj)) {
2699         jobj->set_arraycopy_src();
2700         new_edges++;
2701       }
2702       // and stop here.
2703       continue;
2704     }
2705     if (!add_edge(use, jobj)) {
2706       continue; // No new edge added, there was such edge already.
2707     }
2708     new_edges++;
2709     if (use->is_LocalVar()) {
2710       add_uses_to_worklist(use);
2711       if (use->arraycopy_dst()) {
2712         for (EdgeIterator i(use); i.has_next(); i.next()) {
2713           PointsToNode* e = i.get();
2714           if (e->is_Arraycopy()) {
2715             if (jobj == null_obj) { // null object does not have field edges
2716               continue;
2717             }
2718             // Add edge from arraycopy's destination java object to Arraycopy node.
2719             if (add_edge(jobj, e)) {
2720               new_edges++;
2721               jobj->set_arraycopy_dst();
2722             }
2723           }
2724         }
2725       }
2726     } else {
2727       // Added new edge to stored in field values.
2728       // Put on worklist all field's uses (loads) and
2729       // related field nodes (same base and offset).
2730       add_field_uses_to_worklist(use->as_Field());
2731     }
2732   }
2733   _worklist.clear();
2734   _in_worklist.reset();
2735   return new_edges;
2736 }
2737 
2738 // Put on worklist all related field nodes.
2739 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
2740   assert(field->is_oop(), "sanity");
2741   int offset = field->offset();
2742   add_uses_to_worklist(field);
2743   // Loop over all bases of this field and push on worklist Field nodes
2744   // with the same offset and base (since they may reference the same field).
2745   for (BaseIterator i(field); i.has_next(); i.next()) {
2746     PointsToNode* base = i.get();
2747     add_fields_to_worklist(field, base);
2748     // Check if the base was source object of arraycopy and go over arraycopy's
2749     // destination objects since values stored to a field of source object are
2750     // accessible by uses (loads) of fields of destination objects.
2751     if (base->arraycopy_src()) {
2752       for (UseIterator j(base); j.has_next(); j.next()) {
2753         PointsToNode* arycp = j.get();
2754         if (arycp->is_Arraycopy()) {
2755           for (UseIterator k(arycp); k.has_next(); k.next()) {
2756             PointsToNode* abase = k.get();
2757             if (abase->arraycopy_dst() && abase != base) {
2758               // Look for the same arraycopy reference.
2759               add_fields_to_worklist(field, abase);
2760             }
2761           }
2762         }
2763       }
2764     }
2765   }
2766 }
2767 
2768 // Put on worklist all related field nodes.
2769 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
2770   int offset = field->offset();
2771   if (base->is_LocalVar()) {
2772     for (UseIterator j(base); j.has_next(); j.next()) {
2773       PointsToNode* f = j.get();
2774       if (PointsToNode::is_base_use(f)) { // Field
2775         f = PointsToNode::get_use_node(f);
2776         if (f == field || !f->as_Field()->is_oop()) {
2777           continue;
2778         }
2779         int offs = f->as_Field()->offset();
2780         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
2781           add_to_worklist(f);
2782         }
2783       }
2784     }
2785   } else {
2786     assert(base->is_JavaObject(), "sanity");
2787     if (// Skip phantom_object since it is only used to indicate that
2788         // this field's content globally escapes.
2789         (base != phantom_obj) &&
2790         // null object node does not have fields.
2791         (base != null_obj)) {
2792       for (EdgeIterator i(base); i.has_next(); i.next()) {
2793         PointsToNode* f = i.get();
2794         // Skip arraycopy edge since store to destination object field
2795         // does not update value in source object field.
2796         if (f->is_Arraycopy()) {
2797           assert(base->arraycopy_dst(), "sanity");
2798           continue;
2799         }
2800         if (f == field || !f->as_Field()->is_oop()) {
2801           continue;
2802         }
2803         int offs = f->as_Field()->offset();
2804         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
2805           add_to_worklist(f);
2806         }
2807       }
2808     }
2809   }
2810 }
2811 
2812 // Find fields which have unknown value.
2813 int ConnectionGraph::find_field_value(FieldNode* field) {
2814   // Escaped fields should have init value already.
2815   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
2816   int new_edges = 0;
2817   for (BaseIterator i(field); i.has_next(); i.next()) {
2818     PointsToNode* base = i.get();
2819     if (base->is_JavaObject()) {
2820       // Skip Allocate's fields which will be processed later.
2821       if (base->ideal_node()->is_Allocate()) {
2822         return 0;
2823       }
2824       assert(base == null_obj, "only null ptr base expected here");
2825     }
2826   }
2827   if (add_edge(field, phantom_obj)) {
2828     // New edge was added
2829     new_edges++;
2830     add_field_uses_to_worklist(field);
2831   }
2832   return new_edges;
2833 }
2834 
2835 // Find fields initializing values for allocations.
2836 int ConnectionGraph::find_init_values_phantom(JavaObjectNode* pta) {
2837   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
2838   PointsToNode* init_val = phantom_obj;
2839   Node* alloc = pta->ideal_node();
2840 
2841   // Do nothing for Allocate nodes since its fields values are
2842   // "known" unless they are initialized by arraycopy/clone.
2843   if (alloc->is_Allocate() && !pta->arraycopy_dst()) {
2844     if (alloc->as_Allocate()->in(AllocateNode::InitValue) != nullptr) {
2845       // Null-free inline type arrays are initialized with an init value instead of null
2846       init_val = ptnode_adr(alloc->as_Allocate()->in(AllocateNode::InitValue)->_idx);
2847       assert(init_val != nullptr, "init value should be registered");
2848     } else {
2849       return 0;
2850     }
2851   }
2852   // Non-escaped allocation returned from Java or runtime call has unknown values in fields.
2853   assert(pta->arraycopy_dst() || alloc->is_CallStaticJava() || init_val != phantom_obj, "sanity");
2854 #ifdef ASSERT
2855   if (alloc->is_CallStaticJava() && alloc->as_CallStaticJava()->method() == nullptr) {
2856     const char* name = alloc->as_CallStaticJava()->_name;
2857     assert(strncmp(name, "C2 Runtime multianewarray", 25) == 0 ||
2858            strncmp(name, "C2 Runtime load_unknown_inline", 30) == 0 ||
2859            strncmp(name, "store_inline_type_fields_to_buf", 31) == 0, "sanity");
2860   }
2861 #endif
2862   // Non-escaped allocation returned from Java or runtime call have unknown values in fields.
2863   int new_edges = 0;
2864   for (EdgeIterator i(pta); i.has_next(); i.next()) {
2865     PointsToNode* field = i.get();
2866     if (field->is_Field() && field->as_Field()->is_oop()) {
2867       if (add_edge(field, init_val)) {
2868         // New edge was added
2869         new_edges++;
2870         add_field_uses_to_worklist(field->as_Field());
2871       }
2872     }
2873   }
2874   return new_edges;
2875 }
2876 
2877 // Find fields initializing values for allocations.
2878 int ConnectionGraph::find_init_values_null(JavaObjectNode* pta, PhaseValues* phase) {
2879   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
2880   Node* alloc = pta->ideal_node();
2881   // Do nothing for Call nodes since its fields values are unknown.
2882   if (!alloc->is_Allocate() || alloc->as_Allocate()->in(AllocateNode::InitValue) != nullptr) {
2883     return 0;
2884   }
2885   InitializeNode* ini = alloc->as_Allocate()->initialization();
2886   bool visited_bottom_offset = false;
2887   GrowableArray<int> offsets_worklist;
2888   int new_edges = 0;
2889 
2890   // Check if an oop field's initializing value is recorded and add
2891   // a corresponding null if field's value if it is not recorded.
2892   // Connection Graph does not record a default initialization by null
2893   // captured by Initialize node.
2894   //
2895   for (EdgeIterator i(pta); i.has_next(); i.next()) {
2896     PointsToNode* field = i.get(); // Field (AddP)
2897     if (!field->is_Field() || !field->as_Field()->is_oop()) {
2898       continue; // Not oop field
2899     }
2900     int offset = field->as_Field()->offset();
2901     if (offset == Type::OffsetBot) {
2902       if (!visited_bottom_offset) {
2903         // OffsetBot is used to reference array's element,
2904         // always add reference to null to all Field nodes since we don't
2905         // known which element is referenced.
2906         if (add_edge(field, null_obj)) {
2907           // New edge was added
2908           new_edges++;
2909           add_field_uses_to_worklist(field->as_Field());
2910           visited_bottom_offset = true;
2911         }
2912       }
2913     } else {
2914       // Check only oop fields.
2915       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
2916       if (adr_type->isa_rawptr()) {
2917 #ifdef ASSERT
2918         // Raw pointers are used for initializing stores so skip it
2919         // since it should be recorded already
2920         Node* base = get_addp_base(field->ideal_node());
2921         assert(adr_type->isa_rawptr() && is_captured_store_address(field->ideal_node()), "unexpected pointer type");
2922 #endif
2923         continue;
2924       }
2925       if (!offsets_worklist.contains(offset)) {
2926         offsets_worklist.append(offset);
2927         Node* value = nullptr;
2928         if (ini != nullptr) {
2929           // StoreP::value_basic_type() == T_ADDRESS
2930           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
2931           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
2932           // Make sure initializing store has the same type as this AddP.
2933           // This AddP may reference non existing field because it is on a
2934           // dead branch of bimorphic call which is not eliminated yet.
2935           if (store != nullptr && store->is_Store() &&
2936               store->as_Store()->value_basic_type() == ft) {
2937             value = store->in(MemNode::ValueIn);
2938 #ifdef ASSERT
2939             if (VerifyConnectionGraph) {
2940               // Verify that AddP already points to all objects the value points to.
2941               PointsToNode* val = ptnode_adr(value->_idx);
2942               assert((val != nullptr), "should be processed already");
2943               PointsToNode* missed_obj = nullptr;
2944               if (val->is_JavaObject()) {
2945                 if (!field->points_to(val->as_JavaObject())) {
2946                   missed_obj = val;
2947                 }
2948               } else {
2949                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
2950                   tty->print_cr("----------init store has invalid value -----");
2951                   store->dump();
2952                   val->dump();
2953                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
2954                 }
2955                 for (EdgeIterator j(val); j.has_next(); j.next()) {
2956                   PointsToNode* obj = j.get();
2957                   if (obj->is_JavaObject()) {
2958                     if (!field->points_to(obj->as_JavaObject())) {
2959                       missed_obj = obj;
2960                       break;
2961                     }
2962                   }
2963                 }
2964               }
2965               if (missed_obj != nullptr) {
2966                 tty->print_cr("----------field---------------------------------");
2967                 field->dump();
2968                 tty->print_cr("----------missed reference to object------------");
2969                 missed_obj->dump();
2970                 tty->print_cr("----------object referenced by init store-------");
2971                 store->dump();
2972                 val->dump();
2973                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
2974               }
2975             }
2976 #endif
2977           } else {
2978             // There could be initializing stores which follow allocation.
2979             // For example, a volatile field store is not collected
2980             // by Initialize node.
2981             //
2982             // Need to check for dependent loads to separate such stores from
2983             // stores which follow loads. For now, add initial value null so
2984             // that compare pointers optimization works correctly.
2985           }
2986         }
2987         if (value == nullptr) {
2988           // A field's initializing value was not recorded. Add null.
2989           if (add_edge(field, null_obj)) {
2990             // New edge was added
2991             new_edges++;
2992             add_field_uses_to_worklist(field->as_Field());
2993           }
2994         }
2995       }
2996     }
2997   }
2998   return new_edges;
2999 }
3000 
3001 // Adjust scalar_replaceable state after Connection Graph is built.
3002 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj, Unique_Node_List &reducible_merges) {
3003   // A Phi 'x' is a _candidate_ to be reducible if 'can_reduce_phi(x)'
3004   // returns true. If one of the constraints in this method set 'jobj' to NSR
3005   // then the candidate Phi is discarded. If the Phi has another SR 'jobj' as
3006   // input, 'adjust_scalar_replaceable_state' will eventually be called with
3007   // that other object and the Phi will become a reducible Phi.
3008   // There could be multiple merges involving the same jobj.
3009   Unique_Node_List candidates;
3010 
3011   // Search for non-escaping objects which are not scalar replaceable
3012   // and mark them to propagate the state to referenced objects.
3013 
3014   for (UseIterator i(jobj); i.has_next(); i.next()) {
3015     PointsToNode* use = i.get();
3016     if (use->is_Arraycopy()) {
3017       continue;
3018     }
3019     if (use->is_Field()) {
3020       FieldNode* field = use->as_Field();
3021       assert(field->is_oop() && field->scalar_replaceable(), "sanity");
3022       // 1. An object is not scalar replaceable if the field into which it is
3023       // stored has unknown offset (stored into unknown element of an array).
3024       if (field->offset() == Type::OffsetBot) {
3025         set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored at unknown offset"));
3026         return;
3027       }
3028       for (BaseIterator i(field); i.has_next(); i.next()) {
3029         PointsToNode* base = i.get();
3030         // 2. An object is not scalar replaceable if the field into which it is
3031         // stored has multiple bases one of which is null.
3032         if ((base == null_obj) && (field->base_count() > 1)) {
3033           set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with potentially null base"));
3034           return;
3035         }
3036         // 2.5. An object is not scalar replaceable if the field into which it is
3037         // stored has NSR base.
3038         if (!base->scalar_replaceable()) {
3039           set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with NSR base"));
3040           return;
3041         }
3042       }
3043     }
3044     assert(use->is_Field() || use->is_LocalVar(), "sanity");
3045     // 3. An object is not scalar replaceable if it is merged with other objects
3046     // and we can't remove the merge
3047     for (EdgeIterator j(use); j.has_next(); j.next()) {
3048       PointsToNode* ptn = j.get();
3049       if (ptn->is_JavaObject() && ptn != jobj) {
3050         Node* use_n = use->ideal_node();
3051 
3052         // These other local vars may point to multiple objects through a Phi
3053         // In this case we skip them and see if we can reduce the Phi.
3054         if (use_n->is_CastPP() || use_n->is_CheckCastPP()) {
3055           use_n = use_n->in(1);
3056         }
3057 
3058         // If it's already a candidate or confirmed reducible merge we can skip verification
3059         if (candidates.member(use_n) || reducible_merges.member(use_n)) {
3060           continue;
3061         }
3062 
3063         if (use_n->is_Phi() && can_reduce_phi(use_n->as_Phi())) {
3064           candidates.push(use_n);
3065         } else {
3066           // Mark all objects as NSR if we can't remove the merge
3067           set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA trace_merged_message(ptn)));
3068           set_not_scalar_replaceable(ptn NOT_PRODUCT(COMMA trace_merged_message(jobj)));
3069         }
3070       }
3071     }
3072     if (!jobj->scalar_replaceable()) {
3073       return;
3074     }
3075   }
3076 
3077   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
3078     if (j.get()->is_Arraycopy()) {
3079       continue;
3080     }
3081 
3082     // Non-escaping object node should point only to field nodes.
3083     FieldNode* field = j.get()->as_Field();
3084     int offset = field->as_Field()->offset();
3085 
3086     // 4. An object is not scalar replaceable if it has a field with unknown
3087     // offset (array's element is accessed in loop).
3088     if (offset == Type::OffsetBot) {
3089       set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "has field with unknown offset"));
3090       return;
3091     }
3092     // 5. Currently an object is not scalar replaceable if a LoadStore node
3093     // access its field since the field value is unknown after it.
3094     //
3095     Node* n = field->ideal_node();
3096 
3097     // Test for an unsafe access that was parsed as maybe off heap
3098     // (with a CheckCastPP to raw memory).
3099     assert(n->is_AddP(), "expect an address computation");
3100     if (n->in(AddPNode::Base)->is_top() &&
3101         n->in(AddPNode::Address)->Opcode() == Op_CheckCastPP) {
3102       assert(n->in(AddPNode::Address)->bottom_type()->isa_rawptr(), "raw address so raw cast expected");
3103       assert(_igvn->type(n->in(AddPNode::Address)->in(1))->isa_oopptr(), "cast pattern at unsafe access expected");
3104       set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is used as base of mixed unsafe access"));
3105       return;
3106     }
3107 
3108     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3109       Node* u = n->fast_out(i);
3110       if (u->is_LoadStore() || (u->is_Mem() && u->as_Mem()->is_mismatched_access())) {
3111         set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is used in LoadStore or mismatched access"));
3112         return;
3113       }
3114     }
3115 
3116     // 6. Or the address may point to more then one object. This may produce
3117     // the false positive result (set not scalar replaceable)
3118     // since the flow-insensitive escape analysis can't separate
3119     // the case when stores overwrite the field's value from the case
3120     // when stores happened on different control branches.
3121     //
3122     // Note: it will disable scalar replacement in some cases:
3123     //
3124     //    Point p[] = new Point[1];
3125     //    p[0] = new Point(); // Will be not scalar replaced
3126     //
3127     // but it will save us from incorrect optimizations in next cases:
3128     //
3129     //    Point p[] = new Point[1];
3130     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
3131     //
3132     if (field->base_count() > 1 && candidates.size() == 0) {
3133       if (has_non_reducible_merge(field, reducible_merges)) {
3134         for (BaseIterator i(field); i.has_next(); i.next()) {
3135           PointsToNode* base = i.get();
3136           // Don't take into account LocalVar nodes which
3137           // may point to only one object which should be also
3138           // this field's base by now.
3139           if (base->is_JavaObject() && base != jobj) {
3140             // Mark all bases.
3141             set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "may point to more than one object"));
3142             set_not_scalar_replaceable(base NOT_PRODUCT(COMMA "may point to more than one object"));
3143           }
3144         }
3145 
3146         if (!jobj->scalar_replaceable()) {
3147           return;
3148         }
3149       }
3150     }
3151   }
3152 
3153   // The candidate is truly a reducible merge only if none of the other
3154   // constraints ruled it as NSR. There could be multiple merges involving the
3155   // same jobj.
3156   assert(jobj->scalar_replaceable(), "sanity");
3157   for (uint i = 0; i < candidates.size(); i++ ) {
3158     Node* candidate = candidates.at(i);
3159     reducible_merges.push(candidate);
3160   }
3161 }
3162 
3163 bool ConnectionGraph::has_non_reducible_merge(FieldNode* field, Unique_Node_List& reducible_merges) {
3164   for (BaseIterator i(field); i.has_next(); i.next()) {
3165     Node* base = i.get()->ideal_node();
3166     if (base->is_Phi() && !reducible_merges.member(base)) {
3167       return true;
3168     }
3169   }
3170   return false;
3171 }
3172 
3173 void ConnectionGraph::revisit_reducible_phi_status(JavaObjectNode* jobj, Unique_Node_List& reducible_merges) {
3174   assert(jobj != nullptr && !jobj->scalar_replaceable(), "jobj should be set as NSR before calling this function.");
3175 
3176   // Look for 'phis' that refer to 'jobj' as the last
3177   // remaining scalar replaceable input.
3178   uint reducible_merges_cnt = reducible_merges.size();
3179   for (uint i = 0; i < reducible_merges_cnt; i++) {
3180     Node* phi = reducible_merges.at(i);
3181 
3182     // This 'Phi' will be a 'good' if it still points to
3183     // at least one scalar replaceable object. Note that 'obj'
3184     // was/should be marked as NSR before calling this function.
3185     bool good_phi = false;
3186 
3187     for (uint j = 1; j < phi->req(); j++) {
3188       JavaObjectNode* phi_in_obj = unique_java_object(phi->in(j));
3189       if (phi_in_obj != nullptr && phi_in_obj->scalar_replaceable()) {
3190         good_phi = true;
3191         break;
3192       }
3193     }
3194 
3195     if (!good_phi) {
3196       NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Phi %d became non-reducible after node %d became NSR.", phi->_idx, jobj->ideal_node()->_idx);)
3197       reducible_merges.remove(i);
3198 
3199       // Decrement the index because the 'remove' call above actually
3200       // moves the last entry of the list to position 'i'.
3201       i--;
3202 
3203       reducible_merges_cnt--;
3204     }
3205   }
3206 }
3207 
3208 // Propagate NSR (Not scalar replaceable) state.
3209 void ConnectionGraph::find_scalar_replaceable_allocs(GrowableArray<JavaObjectNode*>& jobj_worklist, Unique_Node_List &reducible_merges) {
3210   int jobj_length = jobj_worklist.length();
3211   bool found_nsr_alloc = true;
3212   while (found_nsr_alloc) {
3213     found_nsr_alloc = false;
3214     for (int next = 0; next < jobj_length; ++next) {
3215       JavaObjectNode* jobj = jobj_worklist.at(next);
3216       for (UseIterator i(jobj); (jobj->scalar_replaceable() && i.has_next()); i.next()) {
3217         PointsToNode* use = i.get();
3218         if (use->is_Field()) {
3219           FieldNode* field = use->as_Field();
3220           assert(field->is_oop() && field->scalar_replaceable(), "sanity");
3221           assert(field->offset() != Type::OffsetBot, "sanity");
3222           for (BaseIterator i(field); i.has_next(); i.next()) {
3223             PointsToNode* base = i.get();
3224             // An object is not scalar replaceable if the field into which
3225             // it is stored has NSR base.
3226             if ((base != null_obj) && !base->scalar_replaceable()) {
3227               set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with NSR base"));
3228               // Any merge that had only 'jobj' as scalar-replaceable will now be non-reducible,
3229               // because there is no point in reducing a Phi that won't improve the number of SR
3230               // objects.
3231               revisit_reducible_phi_status(jobj, reducible_merges);
3232               found_nsr_alloc = true;
3233               break;
3234             }
3235           }
3236         } else if (use->is_LocalVar()) {
3237           Node* phi = use->ideal_node();
3238           if (phi->Opcode() == Op_Phi && reducible_merges.member(phi) && !can_reduce_phi(phi->as_Phi())) {
3239             set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is merged in a non-reducible phi"));
3240             reducible_merges.yank(phi);
3241             found_nsr_alloc = true;
3242             break;
3243           }
3244         }
3245       }
3246     }
3247   }
3248 }
3249 
3250 #ifdef ASSERT
3251 void ConnectionGraph::verify_connection_graph(
3252                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
3253                          GrowableArray<JavaObjectNode*>& non_escaped_allocs_worklist,
3254                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
3255                          GrowableArray<Node*>& addp_worklist) {
3256   // Verify that graph is complete - no new edges could be added.
3257   int java_objects_length = java_objects_worklist.length();
3258   int non_escaped_length  = non_escaped_allocs_worklist.length();
3259   int new_edges = 0;
3260   for (int next = 0; next < java_objects_length; ++next) {
3261     JavaObjectNode* ptn = java_objects_worklist.at(next);
3262     new_edges += add_java_object_edges(ptn, true);
3263   }
3264   assert(new_edges == 0, "graph was not complete");
3265   // Verify that escape state is final.
3266   int length = non_escaped_allocs_worklist.length();
3267   find_non_escaped_objects(ptnodes_worklist, non_escaped_allocs_worklist);
3268   assert((non_escaped_length == non_escaped_allocs_worklist.length()) &&
3269          (non_escaped_length == length) &&
3270          (_worklist.length() == 0), "escape state was not final");
3271 
3272   // Verify fields information.
3273   int addp_length = addp_worklist.length();
3274   for (int next = 0; next < addp_length; ++next ) {
3275     Node* n = addp_worklist.at(next);
3276     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
3277     if (field->is_oop()) {
3278       // Verify that field has all bases
3279       Node* base = get_addp_base(n);
3280       PointsToNode* ptn = ptnode_adr(base->_idx);
3281       if (ptn->is_JavaObject()) {
3282         assert(field->has_base(ptn->as_JavaObject()), "sanity");
3283       } else {
3284         assert(ptn->is_LocalVar(), "sanity");
3285         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
3286           PointsToNode* e = i.get();
3287           if (e->is_JavaObject()) {
3288             assert(field->has_base(e->as_JavaObject()), "sanity");
3289           }
3290         }
3291       }
3292       // Verify that all fields have initializing values.
3293       if (field->edge_count() == 0) {
3294         tty->print_cr("----------field does not have references----------");
3295         field->dump();
3296         for (BaseIterator i(field); i.has_next(); i.next()) {
3297           PointsToNode* base = i.get();
3298           tty->print_cr("----------field has next base---------------------");
3299           base->dump();
3300           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
3301             tty->print_cr("----------base has fields-------------------------");
3302             for (EdgeIterator j(base); j.has_next(); j.next()) {
3303               j.get()->dump();
3304             }
3305             tty->print_cr("----------base has references---------------------");
3306             for (UseIterator j(base); j.has_next(); j.next()) {
3307               j.get()->dump();
3308             }
3309           }
3310         }
3311         for (UseIterator i(field); i.has_next(); i.next()) {
3312           i.get()->dump();
3313         }
3314         assert(field->edge_count() > 0, "sanity");
3315       }
3316     }
3317   }
3318 }
3319 #endif
3320 
3321 // Optimize ideal graph.
3322 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
3323                                            GrowableArray<MemBarStoreStoreNode*>& storestore_worklist) {
3324   Compile* C = _compile;
3325   PhaseIterGVN* igvn = _igvn;
3326   if (EliminateLocks) {
3327     // Mark locks before changing ideal graph.
3328     int cnt = C->macro_count();
3329     for (int i = 0; i < cnt; i++) {
3330       Node *n = C->macro_node(i);
3331       if (n->is_AbstractLock()) { // Lock and Unlock nodes
3332         AbstractLockNode* alock = n->as_AbstractLock();
3333         if (!alock->is_non_esc_obj()) {
3334           const Type* obj_type = igvn->type(alock->obj_node());
3335           if (can_eliminate_lock(alock) && !obj_type->is_inlinetypeptr()) {
3336             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
3337             // The lock could be marked eliminated by lock coarsening
3338             // code during first IGVN before EA. Replace coarsened flag
3339             // to eliminate all associated locks/unlocks.
3340 #ifdef ASSERT
3341             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
3342 #endif
3343             alock->set_non_esc_obj();
3344           }
3345         }
3346       }
3347     }
3348   }
3349 
3350   if (OptimizePtrCompare) {
3351     for (int i = 0; i < ptr_cmp_worklist.length(); i++) {
3352       Node *n = ptr_cmp_worklist.at(i);
3353       assert(n->Opcode() == Op_CmpN || n->Opcode() == Op_CmpP, "must be");
3354       const TypeInt* tcmp = optimize_ptr_compare(n->in(1), n->in(2));
3355       if (tcmp->singleton()) {
3356         Node* cmp = igvn->makecon(tcmp);
3357 #ifndef PRODUCT
3358         if (PrintOptimizePtrCompare) {
3359           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"));
3360           if (Verbose) {
3361             n->dump(1);
3362           }
3363         }
3364 #endif
3365         igvn->replace_node(n, cmp);
3366       }
3367     }
3368   }
3369 
3370   // For MemBarStoreStore nodes added in library_call.cpp, check
3371   // escape status of associated AllocateNode and optimize out
3372   // MemBarStoreStore node if the allocated object never escapes.
3373   for (int i = 0; i < storestore_worklist.length(); i++) {
3374     Node* storestore = storestore_worklist.at(i);
3375     Node* alloc = storestore->in(MemBarNode::Precedent)->in(0);
3376     if (alloc->is_Allocate() && not_global_escape(alloc)) {
3377       if (alloc->in(AllocateNode::InlineType) != nullptr) {
3378         // Non-escaping inline type buffer allocations don't require a membar
3379         storestore->as_MemBar()->remove(_igvn);
3380       } else {
3381         MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
3382         mb->init_req(TypeFunc::Memory,  storestore->in(TypeFunc::Memory));
3383         mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
3384         igvn->register_new_node_with_optimizer(mb);
3385         igvn->replace_node(storestore, mb);
3386       }
3387     }
3388   }
3389 }
3390 
3391 // Atomic flat accesses on non-escaping objects can be optimized to non-atomic accesses
3392 void ConnectionGraph::optimize_flat_accesses(GrowableArray<SafePointNode*>& sfn_worklist) {
3393   PhaseIterGVN& igvn = *_igvn;
3394   bool delay = igvn.delay_transform();
3395   igvn.set_delay_transform(true);
3396   igvn.C->for_each_flat_access([&](Node* n) {
3397     Node* base = n->is_LoadFlat() ? n->as_LoadFlat()->base() : n->as_StoreFlat()->base();
3398     if (!not_global_escape(base)) {
3399       return;
3400     }
3401 
3402     bool expanded;
3403     if (n->is_LoadFlat()) {
3404       expanded = n->as_LoadFlat()->expand_non_atomic(igvn);
3405     } else {
3406       expanded = n->as_StoreFlat()->expand_non_atomic(igvn);
3407     }
3408     if (expanded) {
3409       sfn_worklist.remove(n->as_SafePoint());
3410       igvn.C->remove_flat_access(n);
3411     }
3412   });
3413   igvn.set_delay_transform(delay);
3414 }
3415 
3416 // Optimize objects compare.
3417 const TypeInt* ConnectionGraph::optimize_ptr_compare(Node* left, Node* right) {
3418   const TypeInt* UNKNOWN = TypeInt::CC;    // [-1, 0,1]
3419   if (!OptimizePtrCompare) {
3420     return UNKNOWN;
3421   }
3422   const TypeInt* EQ = TypeInt::CC_EQ; // [0] == ZERO
3423   const TypeInt* NE = TypeInt::CC_GT; // [1] == ONE
3424 
3425   PointsToNode* ptn1 = ptnode_adr(left->_idx);
3426   PointsToNode* ptn2 = ptnode_adr(right->_idx);
3427   JavaObjectNode* jobj1 = unique_java_object(left);
3428   JavaObjectNode* jobj2 = unique_java_object(right);
3429 
3430   // The use of this method during allocation merge reduction may cause 'left'
3431   // or 'right' be something (e.g., a Phi) that isn't in the connection graph or
3432   // that doesn't reference an unique java object.
3433   if (ptn1 == nullptr || ptn2 == nullptr ||
3434       jobj1 == nullptr || jobj2 == nullptr) {
3435     return UNKNOWN;
3436   }
3437 
3438   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
3439   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
3440 
3441   // Check simple cases first.
3442   if (jobj1 != nullptr) {
3443     if (jobj1->escape_state() == PointsToNode::NoEscape) {
3444       if (jobj1 == jobj2) {
3445         // Comparing the same not escaping object.
3446         return EQ;
3447       }
3448       Node* obj = jobj1->ideal_node();
3449       // Comparing not escaping allocation.
3450       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
3451           !ptn2->points_to(jobj1)) {
3452         return NE; // This includes nullness check.
3453       }
3454     }
3455   }
3456   if (jobj2 != nullptr) {
3457     if (jobj2->escape_state() == PointsToNode::NoEscape) {
3458       Node* obj = jobj2->ideal_node();
3459       // Comparing not escaping allocation.
3460       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
3461           !ptn1->points_to(jobj2)) {
3462         return NE; // This includes nullness check.
3463       }
3464     }
3465   }
3466   if (jobj1 != nullptr && jobj1 != phantom_obj &&
3467       jobj2 != nullptr && jobj2 != phantom_obj &&
3468       jobj1->ideal_node()->is_Con() &&
3469       jobj2->ideal_node()->is_Con()) {
3470     // Klass or String constants compare. Need to be careful with
3471     // compressed pointers - compare types of ConN and ConP instead of nodes.
3472     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
3473     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
3474     if (t1->make_ptr() == t2->make_ptr()) {
3475       return EQ;
3476     } else {
3477       return NE;
3478     }
3479   }
3480   if (ptn1->meet(ptn2)) {
3481     return UNKNOWN; // Sets are not disjoint
3482   }
3483 
3484   // Sets are disjoint.
3485   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
3486   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
3487   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
3488   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
3489   if ((set1_has_unknown_ptr && set2_has_null_ptr) ||
3490       (set2_has_unknown_ptr && set1_has_null_ptr)) {
3491     // Check nullness of unknown object.
3492     return UNKNOWN;
3493   }
3494 
3495   // Disjointness by itself is not sufficient since
3496   // alias analysis is not complete for escaped objects.
3497   // Disjoint sets are definitely unrelated only when
3498   // at least one set has only not escaping allocations.
3499   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
3500     if (ptn1->non_escaping_allocation()) {
3501       return NE;
3502     }
3503   }
3504   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
3505     if (ptn2->non_escaping_allocation()) {
3506       return NE;
3507     }
3508   }
3509   return UNKNOWN;
3510 }
3511 
3512 // Connection Graph construction functions.
3513 
3514 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
3515   PointsToNode* ptadr = _nodes.at(n->_idx);
3516   if (ptadr != nullptr) {
3517     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
3518     return;
3519   }
3520   Compile* C = _compile;
3521   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
3522   map_ideal_node(n, ptadr);
3523 }
3524 
3525 PointsToNode* ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
3526   PointsToNode* ptadr = _nodes.at(n->_idx);
3527   if (ptadr != nullptr) {
3528     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
3529     return ptadr;
3530   }
3531   Compile* C = _compile;
3532   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
3533   map_ideal_node(n, ptadr);
3534   return ptadr;
3535 }
3536 
3537 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
3538   PointsToNode* ptadr = _nodes.at(n->_idx);
3539   if (ptadr != nullptr) {
3540     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
3541     return;
3542   }
3543   bool unsafe = false;
3544   bool is_oop = is_oop_field(n, offset, &unsafe);
3545   if (unsafe) {
3546     es = PointsToNode::GlobalEscape;
3547   }
3548   Compile* C = _compile;
3549   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
3550   map_ideal_node(n, field);
3551 }
3552 
3553 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
3554                                     PointsToNode* src, PointsToNode* dst) {
3555   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
3556   assert((src != null_obj) && (dst != null_obj), "not for ConP null");
3557   PointsToNode* ptadr = _nodes.at(n->_idx);
3558   if (ptadr != nullptr) {
3559     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
3560     return;
3561   }
3562   Compile* C = _compile;
3563   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
3564   map_ideal_node(n, ptadr);
3565   // Add edge from arraycopy node to source object.
3566   (void)add_edge(ptadr, src);
3567   src->set_arraycopy_src();
3568   // Add edge from destination object to arraycopy node.
3569   (void)add_edge(dst, ptadr);
3570   dst->set_arraycopy_dst();
3571 }
3572 
3573 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
3574   const Type* adr_type = n->as_AddP()->bottom_type();
3575   int field_offset = adr_type->isa_aryptr() ? adr_type->isa_aryptr()->field_offset().get() : Type::OffsetBot;
3576   BasicType bt = T_INT;
3577   if (offset == Type::OffsetBot && field_offset == Type::OffsetBot) {
3578     // Check only oop fields.
3579     if (!adr_type->isa_aryptr() ||
3580         adr_type->isa_aryptr()->elem() == Type::BOTTOM ||
3581         adr_type->isa_aryptr()->elem()->make_oopptr() != nullptr) {
3582       // OffsetBot is used to reference array's element. Ignore first AddP.
3583       if (find_second_addp(n, n->in(AddPNode::Base)) == nullptr) {
3584         bt = T_OBJECT;
3585       }
3586     }
3587   } else if (offset != oopDesc::klass_offset_in_bytes()) {
3588     if (adr_type->isa_instptr()) {
3589       ciField* field = _compile->alias_type(adr_type->is_ptr())->field();
3590       if (field != nullptr) {
3591         bt = field->layout_type();
3592       } else {
3593         // Check for unsafe oop field access
3594         if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN) ||
3595             n->has_out_with(Op_GetAndSetP, Op_GetAndSetN, Op_CompareAndExchangeP, Op_CompareAndExchangeN) ||
3596             n->has_out_with(Op_CompareAndSwapP, Op_CompareAndSwapN, Op_WeakCompareAndSwapP, Op_WeakCompareAndSwapN) ||
3597             BarrierSet::barrier_set()->barrier_set_c2()->escape_has_out_with_unsafe_object(n)) {
3598           bt = T_OBJECT;
3599           (*unsafe) = true;
3600         }
3601       }
3602     } else if (adr_type->isa_aryptr()) {
3603       if (offset == arrayOopDesc::length_offset_in_bytes()) {
3604         // Ignore array length load.
3605       } else if (find_second_addp(n, n->in(AddPNode::Base)) != nullptr) {
3606         // Ignore first AddP.
3607       } else {
3608         const Type* elemtype = adr_type->is_aryptr()->elem();
3609         if (adr_type->is_aryptr()->is_flat() && field_offset != Type::OffsetBot) {
3610           ciInlineKlass* vk = elemtype->inline_klass();
3611           field_offset += vk->payload_offset();
3612           ciField* field = vk->get_field_by_offset(field_offset, false);
3613           if (field != nullptr) {
3614             bt = field->layout_type();
3615           } else {
3616             assert(field_offset == vk->payload_offset() + vk->null_marker_offset_in_payload(), "no field or null marker of %s at offset %d", vk->name()->as_utf8(), field_offset);
3617             bt = T_BOOLEAN;
3618           }
3619         } else {
3620           bt = elemtype->array_element_basic_type();
3621         }
3622       }
3623     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
3624       // Allocation initialization, ThreadLocal field access, unsafe access
3625       if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN) ||
3626           n->has_out_with(Op_GetAndSetP, Op_GetAndSetN, Op_CompareAndExchangeP, Op_CompareAndExchangeN) ||
3627           n->has_out_with(Op_CompareAndSwapP, Op_CompareAndSwapN, Op_WeakCompareAndSwapP, Op_WeakCompareAndSwapN) ||
3628           BarrierSet::barrier_set()->barrier_set_c2()->escape_has_out_with_unsafe_object(n)) {
3629         bt = T_OBJECT;
3630       }
3631     }
3632   }
3633   // Note: T_NARROWOOP is not classed as a real reference type
3634   return (is_reference_type(bt) || bt == T_NARROWOOP);
3635 }
3636 
3637 // Returns unique pointed java object or null.
3638 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) const {
3639   // If the node was created after the escape computation we can't answer.
3640   uint idx = n->_idx;
3641   if (idx >= nodes_size()) {
3642     return nullptr;
3643   }
3644   PointsToNode* ptn = ptnode_adr(idx);
3645   if (ptn == nullptr) {
3646     return nullptr;
3647   }
3648   if (ptn->is_JavaObject()) {
3649     return ptn->as_JavaObject();
3650   }
3651   assert(ptn->is_LocalVar(), "sanity");
3652   // Check all java objects it points to.
3653   JavaObjectNode* jobj = nullptr;
3654   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
3655     PointsToNode* e = i.get();
3656     if (e->is_JavaObject()) {
3657       if (jobj == nullptr) {
3658         jobj = e->as_JavaObject();
3659       } else if (jobj != e) {
3660         return nullptr;
3661       }
3662     }
3663   }
3664   return jobj;
3665 }
3666 
3667 // Return true if this node points only to non-escaping allocations.
3668 bool PointsToNode::non_escaping_allocation() {
3669   if (is_JavaObject()) {
3670     Node* n = ideal_node();
3671     if (n->is_Allocate() || n->is_CallStaticJava()) {
3672       return (escape_state() == PointsToNode::NoEscape);
3673     } else {
3674       return false;
3675     }
3676   }
3677   assert(is_LocalVar(), "sanity");
3678   // Check all java objects it points to.
3679   for (EdgeIterator i(this); i.has_next(); i.next()) {
3680     PointsToNode* e = i.get();
3681     if (e->is_JavaObject()) {
3682       Node* n = e->ideal_node();
3683       if ((e->escape_state() != PointsToNode::NoEscape) ||
3684           !(n->is_Allocate() || n->is_CallStaticJava())) {
3685         return false;
3686       }
3687     }
3688   }
3689   return true;
3690 }
3691 
3692 // Return true if we know the node does not escape globally.
3693 bool ConnectionGraph::not_global_escape(Node *n) {
3694   assert(!_collecting, "should not call during graph construction");
3695   // If the node was created after the escape computation we can't answer.
3696   uint idx = n->_idx;
3697   if (idx >= nodes_size()) {
3698     return false;
3699   }
3700   PointsToNode* ptn = ptnode_adr(idx);
3701   if (ptn == nullptr) {
3702     return false; // not in congraph (e.g. ConI)
3703   }
3704   PointsToNode::EscapeState es = ptn->escape_state();
3705   // If we have already computed a value, return it.
3706   if (es >= PointsToNode::GlobalEscape) {
3707     return false;
3708   }
3709   if (ptn->is_JavaObject()) {
3710     return true; // (es < PointsToNode::GlobalEscape);
3711   }
3712   assert(ptn->is_LocalVar(), "sanity");
3713   // Check all java objects it points to.
3714   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
3715     if (i.get()->escape_state() >= PointsToNode::GlobalEscape) {
3716       return false;
3717     }
3718   }
3719   return true;
3720 }
3721 
3722 // Return true if locked object does not escape globally
3723 // and locked code region (identified by BoxLockNode) is balanced:
3724 // all compiled code paths have corresponding Lock/Unlock pairs.
3725 bool ConnectionGraph::can_eliminate_lock(AbstractLockNode* alock) {
3726   if (alock->is_balanced() && not_global_escape(alock->obj_node())) {
3727     if (EliminateNestedLocks) {
3728       // We can mark whole locking region as Local only when only
3729       // one object is used for locking.
3730       alock->box_node()->as_BoxLock()->set_local();
3731     }
3732     return true;
3733   }
3734   return false;
3735 }
3736 
3737 // Helper functions
3738 
3739 // Return true if this node points to specified node or nodes it points to.
3740 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
3741   if (is_JavaObject()) {
3742     return (this == ptn);
3743   }
3744   assert(is_LocalVar() || is_Field(), "sanity");
3745   for (EdgeIterator i(this); i.has_next(); i.next()) {
3746     if (i.get() == ptn) {
3747       return true;
3748     }
3749   }
3750   return false;
3751 }
3752 
3753 // Return true if one node points to an other.
3754 bool PointsToNode::meet(PointsToNode* ptn) {
3755   if (this == ptn) {
3756     return true;
3757   } else if (ptn->is_JavaObject()) {
3758     return this->points_to(ptn->as_JavaObject());
3759   } else if (this->is_JavaObject()) {
3760     return ptn->points_to(this->as_JavaObject());
3761   }
3762   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
3763   int ptn_count =  ptn->edge_count();
3764   for (EdgeIterator i(this); i.has_next(); i.next()) {
3765     PointsToNode* this_e = i.get();
3766     for (int j = 0; j < ptn_count; j++) {
3767       if (this_e == ptn->edge(j)) {
3768         return true;
3769       }
3770     }
3771   }
3772   return false;
3773 }
3774 
3775 #ifdef ASSERT
3776 // Return true if bases point to this java object.
3777 bool FieldNode::has_base(JavaObjectNode* jobj) const {
3778   for (BaseIterator i(this); i.has_next(); i.next()) {
3779     if (i.get() == jobj) {
3780       return true;
3781     }
3782   }
3783   return false;
3784 }
3785 #endif
3786 
3787 bool ConnectionGraph::is_captured_store_address(Node* addp) {
3788   // Handle simple case first.
3789   assert(_igvn->type(addp)->isa_oopptr() == nullptr, "should be raw access");
3790   if (addp->in(AddPNode::Address)->is_Proj() && addp->in(AddPNode::Address)->in(0)->is_Allocate()) {
3791     return true;
3792   } else if (addp->in(AddPNode::Address)->is_Phi()) {
3793     for (DUIterator_Fast imax, i = addp->fast_outs(imax); i < imax; i++) {
3794       Node* addp_use = addp->fast_out(i);
3795       if (addp_use->is_Store()) {
3796         for (DUIterator_Fast jmax, j = addp_use->fast_outs(jmax); j < jmax; j++) {
3797           if (addp_use->fast_out(j)->is_Initialize()) {
3798             return true;
3799           }
3800         }
3801       }
3802     }
3803   }
3804   return false;
3805 }
3806 
3807 int ConnectionGraph::address_offset(Node* adr, PhaseValues* phase) {
3808   const Type *adr_type = phase->type(adr);
3809   if (adr->is_AddP() && adr_type->isa_oopptr() == nullptr && is_captured_store_address(adr)) {
3810     // We are computing a raw address for a store captured by an Initialize
3811     // compute an appropriate address type. AddP cases #3 and #5 (see below).
3812     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
3813     assert(offs != Type::OffsetBot ||
3814            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
3815            "offset must be a constant or it is initialization of array");
3816     return offs;
3817   }
3818   return adr_type->is_ptr()->flat_offset();


3819 }
3820 
3821 Node* ConnectionGraph::get_addp_base(Node *addp) {
3822   assert(addp->is_AddP(), "must be AddP");
3823   //
3824   // AddP cases for Base and Address inputs:
3825   // case #1. Direct object's field reference:
3826   //     Allocate
3827   //       |
3828   //     Proj #5 ( oop result )
3829   //       |
3830   //     CheckCastPP (cast to instance type)
3831   //      | |
3832   //     AddP  ( base == address )
3833   //
3834   // case #2. Indirect object's field reference:
3835   //      Phi
3836   //       |
3837   //     CastPP (cast to instance type)
3838   //      | |
3839   //     AddP  ( base == address )
3840   //
3841   // case #3. Raw object's field reference for Initialize node:
3842   //      Allocate
3843   //        |
3844   //      Proj #5 ( oop result )
3845   //  top   |
3846   //     \  |
3847   //     AddP  ( base == top )
3848   //
3849   // case #4. Array's element reference:
3850   //   {CheckCastPP | CastPP}
3851   //     |  | |
3852   //     |  AddP ( array's element offset )
3853   //     |  |
3854   //     AddP ( array's offset )
3855   //
3856   // case #5. Raw object's field reference for arraycopy stub call:
3857   //          The inline_native_clone() case when the arraycopy stub is called
3858   //          after the allocation before Initialize and CheckCastPP nodes.
3859   //      Allocate
3860   //        |
3861   //      Proj #5 ( oop result )
3862   //       | |
3863   //       AddP  ( base == address )
3864   //
3865   // case #6. Constant Pool, ThreadLocal, CastX2P or
3866   //          Raw object's field reference:
3867   //      {ConP, ThreadLocal, CastX2P, raw Load}
3868   //  top   |
3869   //     \  |
3870   //     AddP  ( base == top )
3871   //
3872   // case #7. Klass's field reference.
3873   //      LoadKlass
3874   //       | |
3875   //       AddP  ( base == address )
3876   //
3877   // case #8. narrow Klass's field reference.
3878   //      LoadNKlass
3879   //       |
3880   //      DecodeN
3881   //       | |
3882   //       AddP  ( base == address )
3883   //
3884   // case #9. Mixed unsafe access
3885   //    {instance}
3886   //        |
3887   //      CheckCastPP (raw)
3888   //  top   |
3889   //     \  |
3890   //     AddP  ( base == top )
3891   //
3892   Node *base = addp->in(AddPNode::Base);
3893   if (base->uncast()->is_top()) { // The AddP case #3 and #6 and #9.
3894     base = addp->in(AddPNode::Address);
3895     while (base->is_AddP()) {
3896       // Case #6 (unsafe access) may have several chained AddP nodes.
3897       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
3898       base = base->in(AddPNode::Address);
3899     }
3900     if (base->Opcode() == Op_CheckCastPP &&
3901         base->bottom_type()->isa_rawptr() &&
3902         _igvn->type(base->in(1))->isa_oopptr()) {
3903       base = base->in(1); // Case #9
3904     } else {
3905       Node* uncast_base = base->uncast();
3906       int opcode = uncast_base->Opcode();
3907       assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
3908              opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
3909              (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != nullptr)) ||
3910              is_captured_store_address(addp), "sanity");
3911     }
3912   }
3913   return base;
3914 }
3915 
3916 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
3917   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
3918   Node* addp2 = addp->raw_out(0);
3919   if (addp->outcnt() == 1 && addp2->is_AddP() &&
3920       addp2->in(AddPNode::Base) == n &&
3921       addp2->in(AddPNode::Address) == addp) {
3922     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
3923     //
3924     // Find array's offset to push it on worklist first and
3925     // as result process an array's element offset first (pushed second)
3926     // to avoid CastPP for the array's offset.
3927     // Otherwise the inserted CastPP (LocalVar) will point to what
3928     // the AddP (Field) points to. Which would be wrong since
3929     // the algorithm expects the CastPP has the same point as
3930     // as AddP's base CheckCastPP (LocalVar).
3931     //
3932     //    ArrayAllocation
3933     //     |
3934     //    CheckCastPP
3935     //     |
3936     //    memProj (from ArrayAllocation CheckCastPP)
3937     //     |  ||
3938     //     |  ||   Int (element index)
3939     //     |  ||    |   ConI (log(element size))
3940     //     |  ||    |   /
3941     //     |  ||   LShift
3942     //     |  ||  /
3943     //     |  AddP (array's element offset)
3944     //     |  |
3945     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
3946     //     | / /
3947     //     AddP (array's offset)
3948     //      |
3949     //     Load/Store (memory operation on array's element)
3950     //
3951     return addp2;
3952   }
3953   return nullptr;
3954 }
3955 
3956 //
3957 // Adjust the type and inputs of an AddP which computes the
3958 // address of a field of an instance
3959 //
3960 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
3961   PhaseGVN* igvn = _igvn;
3962   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
3963   assert(base_t != nullptr && base_t->is_known_instance(), "expecting instance oopptr");
3964   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
3965   if (t == nullptr) {
3966     // We are computing a raw address for a store captured by an Initialize
3967     // compute an appropriate address type (cases #3 and #5).
3968     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
3969     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
3970     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
3971     assert(offs != Type::OffsetBot, "offset must be a constant");
3972     if (base_t->isa_aryptr() != nullptr) {
3973       // In the case of a flat inline type array, each field has its
3974       // own slice so we need to extract the field being accessed from
3975       // the address computation
3976       t = base_t->isa_aryptr()->add_field_offset_and_offset(offs)->is_oopptr();
3977     } else {
3978       t = base_t->add_offset(offs)->is_oopptr();
3979     }
3980   }
3981   int inst_id = base_t->instance_id();
3982   assert(!t->is_known_instance() || t->instance_id() == inst_id,
3983                              "old type must be non-instance or match new type");
3984 
3985   // The type 't' could be subclass of 'base_t'.
3986   // As result t->offset() could be large then base_t's size and it will
3987   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
3988   // constructor verifies correctness of the offset.
3989   //
3990   // It could happened on subclass's branch (from the type profiling
3991   // inlining) which was not eliminated during parsing since the exactness
3992   // of the allocation type was not propagated to the subclass type check.
3993   //
3994   // Or the type 't' could be not related to 'base_t' at all.
3995   // It could happen when CHA type is different from MDO type on a dead path
3996   // (for example, from instanceof check) which is not collapsed during parsing.
3997   //
3998   // Do nothing for such AddP node and don't process its users since
3999   // this code branch will go away.
4000   //
4001   if (!t->is_known_instance() &&
4002       !base_t->maybe_java_subtype_of(t)) {
4003      return false; // bail out
4004   }
4005   const TypePtr* tinst = base_t->add_offset(t->offset());
4006   if (tinst->isa_aryptr() && t->isa_aryptr()) {
4007     // In the case of a flat inline type array, each field has its
4008     // own slice so we need to keep track of the field being accessed.
4009     tinst = tinst->is_aryptr()->with_field_offset(t->is_aryptr()->field_offset().get());
4010     // Keep array properties (not flat/null-free)
4011     tinst = tinst->is_aryptr()->update_properties(t->is_aryptr());
4012     if (tinst == nullptr) {
4013       return false; // Skip dead path with inconsistent properties
4014     }
4015   }
4016 
4017   // Do NOT remove the next line: ensure a new alias index is allocated
4018   // for the instance type. Note: C++ will not remove it since the call
4019   // has side effect.
4020   int alias_idx = _compile->get_alias_index(tinst);
4021   igvn->set_type(addp, tinst);
4022   // record the allocation in the node map
4023   set_map(addp, get_map(base->_idx));
4024   // Set addp's Base and Address to 'base'.
4025   Node *abase = addp->in(AddPNode::Base);
4026   Node *adr   = addp->in(AddPNode::Address);
4027   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
4028       adr->in(0)->_idx == (uint)inst_id) {
4029     // Skip AddP cases #3 and #5.
4030   } else {
4031     assert(!abase->is_top(), "sanity"); // AddP case #3
4032     if (abase != base) {
4033       igvn->hash_delete(addp);
4034       addp->set_req(AddPNode::Base, base);
4035       if (abase == adr) {
4036         addp->set_req(AddPNode::Address, base);
4037       } else {
4038         // AddP case #4 (adr is array's element offset AddP node)
4039 #ifdef ASSERT
4040         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
4041         assert(adr->is_AddP() && atype != nullptr &&
4042                atype->instance_id() == inst_id, "array's element offset should be processed first");
4043 #endif
4044       }
4045       igvn->hash_insert(addp);
4046     }
4047   }
4048   // Put on IGVN worklist since at least addp's type was changed above.
4049   record_for_optimizer(addp);
4050   return true;
4051 }
4052 
4053 //
4054 // Create a new version of orig_phi if necessary. Returns either the newly
4055 // created phi or an existing phi.  Sets create_new to indicate whether a new
4056 // phi was created.  Cache the last newly created phi in the node map.
4057 //
4058 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
4059   Compile *C = _compile;
4060   PhaseGVN* igvn = _igvn;
4061   new_created = false;
4062   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
4063   // nothing to do if orig_phi is bottom memory or matches alias_idx
4064   if (phi_alias_idx == alias_idx) {
4065     return orig_phi;
4066   }
4067   // Have we recently created a Phi for this alias index?
4068   PhiNode *result = get_map_phi(orig_phi->_idx);
4069   if (result != nullptr && C->get_alias_index(result->adr_type()) == alias_idx) {
4070     return result;
4071   }
4072   // Previous check may fail when the same wide memory Phi was split into Phis
4073   // for different memory slices. Search all Phis for this region.
4074   if (result != nullptr) {
4075     Node* region = orig_phi->in(0);
4076     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
4077       Node* phi = region->fast_out(i);
4078       if (phi->is_Phi() &&
4079           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
4080         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
4081         return phi->as_Phi();
4082       }
4083     }
4084   }
4085   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
4086     if (C->do_escape_analysis() == true && !C->failing()) {
4087       // Retry compilation without escape analysis.
4088       // If this is the first failure, the sentinel string will "stick"
4089       // to the Compile object, and the C2Compiler will see it and retry.
4090       C->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4091     }
4092     return nullptr;
4093   }
4094   orig_phi_worklist.append_if_missing(orig_phi);
4095   const TypePtr *atype = C->get_adr_type(alias_idx);
4096   result = PhiNode::make(orig_phi->in(0), nullptr, Type::MEMORY, atype);
4097   C->copy_node_notes_to(result, orig_phi);
4098   igvn->set_type(result, result->bottom_type());
4099   record_for_optimizer(result);
4100   set_map(orig_phi, result);
4101   new_created = true;
4102   return result;
4103 }
4104 
4105 //
4106 // Return a new version of Memory Phi "orig_phi" with the inputs having the
4107 // specified alias index.
4108 //
4109 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *> &orig_phi_worklist, uint rec_depth) {
4110   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
4111   Compile *C = _compile;
4112   PhaseGVN* igvn = _igvn;
4113   bool new_phi_created;
4114   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
4115   if (!new_phi_created) {
4116     return result;
4117   }
4118   GrowableArray<PhiNode *>  phi_list;
4119   GrowableArray<uint>  cur_input;
4120   PhiNode *phi = orig_phi;
4121   uint idx = 1;
4122   bool finished = false;
4123   while(!finished) {
4124     while (idx < phi->req()) {
4125       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist, rec_depth + 1);
4126       if (mem != nullptr && mem->is_Phi()) {
4127         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
4128         if (new_phi_created) {
4129           // found an phi for which we created a new split, push current one on worklist and begin
4130           // processing new one
4131           phi_list.push(phi);
4132           cur_input.push(idx);
4133           phi = mem->as_Phi();
4134           result = newphi;
4135           idx = 1;
4136           continue;
4137         } else {
4138           mem = newphi;
4139         }
4140       }
4141       if (C->failing()) {
4142         return nullptr;
4143       }
4144       result->set_req(idx++, mem);
4145     }
4146 #ifdef ASSERT
4147     // verify that the new Phi has an input for each input of the original
4148     assert( phi->req() == result->req(), "must have same number of inputs.");
4149     assert( result->in(0) != nullptr && result->in(0) == phi->in(0), "regions must match");
4150 #endif
4151     // Check if all new phi's inputs have specified alias index.
4152     // Otherwise use old phi.
4153     for (uint i = 1; i < phi->req(); i++) {
4154       Node* in = result->in(i);
4155       assert((phi->in(i) == nullptr) == (in == nullptr), "inputs must correspond.");
4156     }
4157     // we have finished processing a Phi, see if there are any more to do
4158     finished = (phi_list.length() == 0 );
4159     if (!finished) {
4160       phi = phi_list.pop();
4161       idx = cur_input.pop();
4162       PhiNode *prev_result = get_map_phi(phi->_idx);
4163       prev_result->set_req(idx++, result);
4164       result = prev_result;
4165     }
4166   }
4167   return result;
4168 }
4169 
4170 //
4171 // The next methods are derived from methods in MemNode.
4172 //
4173 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
4174   Node *mem = mmem;
4175   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
4176   // means an array I have not precisely typed yet.  Do not do any
4177   // alias stuff with it any time soon.
4178   if (toop->base() != Type::AnyPtr &&
4179       !(toop->isa_instptr() &&
4180         toop->is_instptr()->instance_klass()->is_java_lang_Object() &&
4181         toop->offset() == Type::OffsetBot)) {
4182     mem = mmem->memory_at(alias_idx);
4183     // Update input if it is progress over what we have now
4184   }
4185   return mem;
4186 }
4187 
4188 //
4189 // Move memory users to their memory slices.
4190 //
4191 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
4192   Compile* C = _compile;
4193   PhaseGVN* igvn = _igvn;
4194   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
4195   assert(tp != nullptr, "ptr type");
4196   int alias_idx = C->get_alias_index(tp);
4197   int general_idx = C->get_general_index(alias_idx);
4198 
4199   // Move users first
4200   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4201     Node* use = n->fast_out(i);
4202     if (use->is_MergeMem()) {
4203       MergeMemNode* mmem = use->as_MergeMem();
4204       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
4205       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
4206         continue; // Nothing to do
4207       }
4208       // Replace previous general reference to mem node.
4209       uint orig_uniq = C->unique();
4210       Node* m = find_inst_mem(n, general_idx, orig_phis);
4211       assert(orig_uniq == C->unique(), "no new nodes");
4212       mmem->set_memory_at(general_idx, m);
4213       --imax;
4214       --i;
4215     } else if (use->is_MemBar()) {
4216       assert(!use->is_Initialize(), "initializing stores should not be moved");
4217       if (use->req() > MemBarNode::Precedent &&
4218           use->in(MemBarNode::Precedent) == n) {
4219         // Don't move related membars.
4220         record_for_optimizer(use);
4221         continue;
4222       }
4223       tp = use->as_MemBar()->adr_type()->isa_ptr();
4224       if ((tp != nullptr && C->get_alias_index(tp) == alias_idx) ||
4225           alias_idx == general_idx) {
4226         continue; // Nothing to do
4227       }
4228       // Move to general memory slice.
4229       uint orig_uniq = C->unique();
4230       Node* m = find_inst_mem(n, general_idx, orig_phis);
4231       assert(orig_uniq == C->unique(), "no new nodes");
4232       igvn->hash_delete(use);
4233       imax -= use->replace_edge(n, m, igvn);
4234       igvn->hash_insert(use);
4235       record_for_optimizer(use);
4236       --i;
4237 #ifdef ASSERT
4238     } else if (use->is_Mem()) {
4239       // Memory nodes should have new memory input.
4240       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
4241       assert(tp != nullptr, "ptr type");
4242       int idx = C->get_alias_index(tp);
4243       assert(get_map(use->_idx) != nullptr || idx == alias_idx,
4244              "Following memory nodes should have new memory input or be on the same memory slice");
4245     } else if (use->is_Phi()) {
4246       // Phi nodes should be split and moved already.
4247       tp = use->as_Phi()->adr_type()->isa_ptr();
4248       assert(tp != nullptr, "ptr type");
4249       int idx = C->get_alias_index(tp);
4250       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
4251     } else {
4252       use->dump();
4253       assert(false, "should not be here");
4254 #endif
4255     }
4256   }
4257 }
4258 
4259 //
4260 // Search memory chain of "mem" to find a MemNode whose address
4261 // is the specified alias index.
4262 //
4263 #define FIND_INST_MEM_RECURSION_DEPTH_LIMIT 1000
4264 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis, uint rec_depth) {
4265   if (rec_depth > FIND_INST_MEM_RECURSION_DEPTH_LIMIT) {
4266     _compile->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4267     return nullptr;
4268   }
4269   if (orig_mem == nullptr) {
4270     return orig_mem;
4271   }
4272   Compile* C = _compile;
4273   PhaseGVN* igvn = _igvn;
4274   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
4275   bool is_instance = (toop != nullptr) && toop->is_known_instance();
4276   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
4277   Node *prev = nullptr;
4278   Node *result = orig_mem;
4279   while (prev != result) {
4280     prev = result;
4281     if (result == start_mem) {
4282       break;  // hit one of our sentinels
4283     }
4284     if (result->is_Mem()) {
4285       const Type *at = igvn->type(result->in(MemNode::Address));
4286       if (at == Type::TOP) {
4287         break; // Dead
4288       }
4289       assert (at->isa_ptr() != nullptr, "pointer type required.");
4290       int idx = C->get_alias_index(at->is_ptr());
4291       if (idx == alias_idx) {
4292         break; // Found
4293       }
4294       if (!is_instance && (at->isa_oopptr() == nullptr ||
4295                            !at->is_oopptr()->is_known_instance())) {
4296         break; // Do not skip store to general memory slice.
4297       }
4298       result = result->in(MemNode::Memory);
4299     }
4300     if (!is_instance) {
4301       continue;  // don't search further for non-instance types
4302     }
4303     // skip over a call which does not affect this memory slice
4304     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
4305       Node *proj_in = result->in(0);
4306       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
4307         break;  // hit one of our sentinels
4308       } else if (proj_in->is_Call()) {
4309         // ArrayCopy node processed here as well
4310         CallNode *call = proj_in->as_Call();
4311         if (!call->may_modify(toop, igvn)) {
4312           result = call->in(TypeFunc::Memory);
4313         }
4314       } else if (proj_in->is_Initialize()) {
4315         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
4316         // Stop if this is the initialization for the object instance which
4317         // which contains this memory slice, otherwise skip over it.
4318         if (alloc == nullptr || alloc->_idx != (uint)toop->instance_id()) {
4319           result = proj_in->in(TypeFunc::Memory);
4320         }
4321       } else if (proj_in->is_MemBar()) {
4322         // Check if there is an array copy for a clone
4323         // Step over GC barrier when ReduceInitialCardMarks is disabled
4324         BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
4325         Node* control_proj_ac = bs->step_over_gc_barrier(proj_in->in(0));
4326 
4327         if (control_proj_ac->is_Proj() && control_proj_ac->in(0)->is_ArrayCopy()) {
4328           // Stop if it is a clone
4329           ArrayCopyNode* ac = control_proj_ac->in(0)->as_ArrayCopy();
4330           if (ac->may_modify(toop, igvn)) {
4331             break;
4332           }
4333         }
4334         result = proj_in->in(TypeFunc::Memory);
4335       }
4336     } else if (result->is_MergeMem()) {
4337       MergeMemNode *mmem = result->as_MergeMem();
4338       result = step_through_mergemem(mmem, alias_idx, toop);
4339       if (result == mmem->base_memory()) {
4340         // Didn't find instance memory, search through general slice recursively.
4341         result = mmem->memory_at(C->get_general_index(alias_idx));
4342         result = find_inst_mem(result, alias_idx, orig_phis, rec_depth + 1);
4343         if (C->failing()) {
4344           return nullptr;
4345         }
4346         mmem->set_memory_at(alias_idx, result);
4347       }
4348     } else if (result->is_Phi() &&
4349                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
4350       Node *un = result->as_Phi()->unique_input(igvn);
4351       if (un != nullptr) {
4352         orig_phis.append_if_missing(result->as_Phi());
4353         result = un;
4354       } else {
4355         break;
4356       }
4357     } else if (result->is_ClearArray()) {
4358       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
4359         // Can not bypass initialization of the instance
4360         // we are looking for.
4361         break;
4362       }
4363       // Otherwise skip it (the call updated 'result' value).
4364     } else if (result->Opcode() == Op_SCMemProj) {
4365       Node* mem = result->in(0);
4366       Node* adr = nullptr;
4367       if (mem->is_LoadStore()) {
4368         adr = mem->in(MemNode::Address);
4369       } else {
4370         assert(mem->Opcode() == Op_EncodeISOArray ||
4371                mem->Opcode() == Op_StrCompressedCopy, "sanity");
4372         adr = mem->in(3); // Memory edge corresponds to destination array
4373       }
4374       const Type *at = igvn->type(adr);
4375       if (at != Type::TOP) {
4376         assert(at->isa_ptr() != nullptr, "pointer type required.");
4377         int idx = C->get_alias_index(at->is_ptr());
4378         if (idx == alias_idx) {
4379           // Assert in debug mode
4380           assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
4381           break; // In product mode return SCMemProj node
4382         }
4383       }
4384       result = mem->in(MemNode::Memory);
4385     } else if (result->Opcode() == Op_StrInflatedCopy) {
4386       Node* adr = result->in(3); // Memory edge corresponds to destination array
4387       const Type *at = igvn->type(adr);
4388       if (at != Type::TOP) {
4389         assert(at->isa_ptr() != nullptr, "pointer type required.");
4390         int idx = C->get_alias_index(at->is_ptr());
4391         if (idx == alias_idx) {
4392           // Assert in debug mode
4393           assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
4394           break; // In product mode return SCMemProj node
4395         }
4396       }
4397       result = result->in(MemNode::Memory);
4398     }
4399   }
4400   if (result->is_Phi()) {
4401     PhiNode *mphi = result->as_Phi();
4402     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
4403     const TypePtr *t = mphi->adr_type();
4404     if (!is_instance) {
4405       // Push all non-instance Phis on the orig_phis worklist to update inputs
4406       // during Phase 4 if needed.
4407       orig_phis.append_if_missing(mphi);
4408     } else if (C->get_alias_index(t) != alias_idx) {
4409       // Create a new Phi with the specified alias index type.
4410       result = split_memory_phi(mphi, alias_idx, orig_phis, rec_depth + 1);
4411     }
4412   }
4413   // the result is either MemNode, PhiNode, InitializeNode.
4414   return result;
4415 }
4416 
4417 //
4418 //  Convert the types of non-escaped object to instance types where possible,
4419 //  propagate the new type information through the graph, and update memory
4420 //  edges and MergeMem inputs to reflect the new type.
4421 //
4422 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
4423 //  The processing is done in 4 phases:
4424 //
4425 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
4426 //            types for the CheckCastPP for allocations where possible.
4427 //            Propagate the new types through users as follows:
4428 //               casts and Phi:  push users on alloc_worklist
4429 //               AddP:  cast Base and Address inputs to the instance type
4430 //                      push any AddP users on alloc_worklist and push any memnode
4431 //                      users onto memnode_worklist.
4432 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
4433 //            search the Memory chain for a store with the appropriate type
4434 //            address type.  If a Phi is found, create a new version with
4435 //            the appropriate memory slices from each of the Phi inputs.
4436 //            For stores, process the users as follows:
4437 //               MemNode:  push on memnode_worklist
4438 //               MergeMem: push on mergemem_worklist
4439 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
4440 //            moving the first node encountered of each  instance type to the
4441 //            the input corresponding to its alias index.
4442 //            appropriate memory slice.
4443 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
4444 //
4445 // In the following example, the CheckCastPP nodes are the cast of allocation
4446 // results and the allocation of node 29 is non-escaped and eligible to be an
4447 // instance type.
4448 //
4449 // We start with:
4450 //
4451 //     7 Parm #memory
4452 //    10  ConI  "12"
4453 //    19  CheckCastPP   "Foo"
4454 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
4455 //    29  CheckCastPP   "Foo"
4456 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
4457 //
4458 //    40  StoreP  25   7  20   ... alias_index=4
4459 //    50  StoreP  35  40  30   ... alias_index=4
4460 //    60  StoreP  45  50  20   ... alias_index=4
4461 //    70  LoadP    _  60  30   ... alias_index=4
4462 //    80  Phi     75  50  60   Memory alias_index=4
4463 //    90  LoadP    _  80  30   ... alias_index=4
4464 //   100  LoadP    _  80  20   ... alias_index=4
4465 //
4466 //
4467 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
4468 // and creating a new alias index for node 30.  This gives:
4469 //
4470 //     7 Parm #memory
4471 //    10  ConI  "12"
4472 //    19  CheckCastPP   "Foo"
4473 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
4474 //    29  CheckCastPP   "Foo"  iid=24
4475 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
4476 //
4477 //    40  StoreP  25   7  20   ... alias_index=4
4478 //    50  StoreP  35  40  30   ... alias_index=6
4479 //    60  StoreP  45  50  20   ... alias_index=4
4480 //    70  LoadP    _  60  30   ... alias_index=6
4481 //    80  Phi     75  50  60   Memory alias_index=4
4482 //    90  LoadP    _  80  30   ... alias_index=6
4483 //   100  LoadP    _  80  20   ... alias_index=4
4484 //
4485 // In phase 2, new memory inputs are computed for the loads and stores,
4486 // And a new version of the phi is created.  In phase 4, the inputs to
4487 // node 80 are updated and then the memory nodes are updated with the
4488 // values computed in phase 2.  This results in:
4489 //
4490 //     7 Parm #memory
4491 //    10  ConI  "12"
4492 //    19  CheckCastPP   "Foo"
4493 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
4494 //    29  CheckCastPP   "Foo"  iid=24
4495 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
4496 //
4497 //    40  StoreP  25  7   20   ... alias_index=4
4498 //    50  StoreP  35  7   30   ... alias_index=6
4499 //    60  StoreP  45  40  20   ... alias_index=4
4500 //    70  LoadP    _  50  30   ... alias_index=6
4501 //    80  Phi     75  40  60   Memory alias_index=4
4502 //   120  Phi     75  50  50   Memory alias_index=6
4503 //    90  LoadP    _ 120  30   ... alias_index=6
4504 //   100  LoadP    _  80  20   ... alias_index=4
4505 //
4506 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist,
4507                                          GrowableArray<ArrayCopyNode*> &arraycopy_worklist,
4508                                          GrowableArray<MergeMemNode*> &mergemem_worklist,
4509                                          Unique_Node_List &reducible_merges) {
4510   DEBUG_ONLY(Unique_Node_List reduced_merges;)
4511   GrowableArray<Node *>  memnode_worklist;
4512   GrowableArray<PhiNode *>  orig_phis;
4513   PhaseIterGVN  *igvn = _igvn;
4514   uint new_index_start = (uint) _compile->num_alias_types();
4515   VectorSet visited;
4516   ideal_nodes.clear(); // Reset for use with set_map/get_map.
4517   uint unique_old = _compile->unique();
4518 
4519   //  Phase 1:  Process possible allocations from alloc_worklist.
4520   //  Create instance types for the CheckCastPP for allocations where possible.
4521   //
4522   // (Note: don't forget to change the order of the second AddP node on
4523   //  the alloc_worklist if the order of the worklist processing is changed,
4524   //  see the comment in find_second_addp().)
4525   //
4526   while (alloc_worklist.length() != 0) {
4527     Node *n = alloc_worklist.pop();
4528     uint ni = n->_idx;
4529     if (n->is_Call()) {
4530       CallNode *alloc = n->as_Call();
4531       // copy escape information to call node
4532       PointsToNode* ptn = ptnode_adr(alloc->_idx);
4533       PointsToNode::EscapeState es = ptn->escape_state();
4534       // We have an allocation or call which returns a Java object,
4535       // see if it is non-escaped.
4536       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable()) {
4537         continue;
4538       }
4539       // Find CheckCastPP for the allocate or for the return value of a call
4540       n = alloc->result_cast();
4541       if (n == nullptr) {            // No uses except Initialize node
4542         if (alloc->is_Allocate()) {
4543           // Set the scalar_replaceable flag for allocation
4544           // so it could be eliminated if it has no uses.
4545           alloc->as_Allocate()->_is_scalar_replaceable = true;
4546         }
4547         continue;
4548       }
4549       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
4550         // we could reach here for allocate case if one init is associated with many allocs.
4551         if (alloc->is_Allocate()) {
4552           alloc->as_Allocate()->_is_scalar_replaceable = false;
4553         }
4554         continue;
4555       }
4556 
4557       // The inline code for Object.clone() casts the allocation result to
4558       // java.lang.Object and then to the actual type of the allocated
4559       // object. Detect this case and use the second cast.
4560       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
4561       // the allocation result is cast to java.lang.Object and then
4562       // to the actual Array type.
4563       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
4564           && (alloc->is_AllocateArray() ||
4565               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeInstKlassPtr::OBJECT)) {
4566         Node *cast2 = nullptr;
4567         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4568           Node *use = n->fast_out(i);
4569           if (use->is_CheckCastPP()) {
4570             cast2 = use;
4571             break;
4572           }
4573         }
4574         if (cast2 != nullptr) {
4575           n = cast2;
4576         } else {
4577           // Non-scalar replaceable if the allocation type is unknown statically
4578           // (reflection allocation), the object can't be restored during
4579           // deoptimization without precise type.
4580           continue;
4581         }
4582       }
4583 
4584       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
4585       if (t == nullptr) {
4586         continue;  // not a TypeOopPtr
4587       }
4588       if (!t->klass_is_exact()) {
4589         continue; // not an unique type
4590       }
4591       if (alloc->is_Allocate()) {
4592         // Set the scalar_replaceable flag for allocation
4593         // so it could be eliminated.
4594         alloc->as_Allocate()->_is_scalar_replaceable = true;
4595       }
4596       set_escape_state(ptnode_adr(n->_idx), es NOT_PRODUCT(COMMA trace_propagate_message(ptn))); // CheckCastPP escape state
4597       // in order for an object to be scalar-replaceable, it must be:
4598       //   - a direct allocation (not a call returning an object)
4599       //   - non-escaping
4600       //   - eligible to be a unique type
4601       //   - not determined to be ineligible by escape analysis
4602       set_map(alloc, n);
4603       set_map(n, alloc);
4604       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
4605       igvn->hash_delete(n);
4606       igvn->set_type(n,  tinst);
4607       n->raise_bottom_type(tinst);
4608       igvn->hash_insert(n);
4609       record_for_optimizer(n);
4610       // Allocate an alias index for the header fields. Accesses to
4611       // the header emitted during macro expansion wouldn't have
4612       // correct memory state otherwise.
4613       _compile->get_alias_index(tinst->add_offset(oopDesc::mark_offset_in_bytes()));
4614       _compile->get_alias_index(tinst->add_offset(oopDesc::klass_offset_in_bytes()));
4615       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
4616 
4617         // First, put on the worklist all Field edges from Connection Graph
4618         // which is more accurate than putting immediate users from Ideal Graph.
4619         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
4620           PointsToNode* tgt = e.get();
4621           if (tgt->is_Arraycopy()) {
4622             continue;
4623           }
4624           Node* use = tgt->ideal_node();
4625           assert(tgt->is_Field() && use->is_AddP(),
4626                  "only AddP nodes are Field edges in CG");
4627           if (use->outcnt() > 0) { // Don't process dead nodes
4628             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
4629             if (addp2 != nullptr) {
4630               assert(alloc->is_AllocateArray(),"array allocation was expected");
4631               alloc_worklist.append_if_missing(addp2);
4632             }
4633             alloc_worklist.append_if_missing(use);
4634           }
4635         }
4636 
4637         // An allocation may have an Initialize which has raw stores. Scan
4638         // the users of the raw allocation result and push AddP users
4639         // on alloc_worklist.
4640         Node *raw_result = alloc->proj_out_or_null(TypeFunc::Parms);
4641         assert (raw_result != nullptr, "must have an allocation result");
4642         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
4643           Node *use = raw_result->fast_out(i);
4644           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
4645             Node* addp2 = find_second_addp(use, raw_result);
4646             if (addp2 != nullptr) {
4647               assert(alloc->is_AllocateArray(),"array allocation was expected");
4648               alloc_worklist.append_if_missing(addp2);
4649             }
4650             alloc_worklist.append_if_missing(use);
4651           } else if (use->is_MemBar()) {
4652             memnode_worklist.append_if_missing(use);
4653           }
4654         }
4655       }
4656     } else if (n->is_AddP()) {
4657       if (has_reducible_merge_base(n->as_AddP(), reducible_merges)) {
4658         // This AddP will go away when we reduce the Phi
4659         continue;
4660       }
4661       Node* addp_base = get_addp_base(n);
4662       JavaObjectNode* jobj = unique_java_object(addp_base);
4663       if (jobj == nullptr || jobj == phantom_obj) {
4664 #ifdef ASSERT
4665         ptnode_adr(get_addp_base(n)->_idx)->dump();
4666         ptnode_adr(n->_idx)->dump();
4667         assert(jobj != nullptr && jobj != phantom_obj, "escaped allocation");
4668 #endif
4669         _compile->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4670         return;
4671       }
4672       Node *base = get_map(jobj->idx());  // CheckCastPP node
4673       if (!split_AddP(n, base)) continue; // wrong type from dead path
4674     } else if (n->is_Phi() ||
4675                n->is_CheckCastPP() ||
4676                n->is_EncodeP() ||
4677                n->is_DecodeN() ||
4678                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
4679       if (visited.test_set(n->_idx)) {
4680         assert(n->is_Phi(), "loops only through Phi's");
4681         continue;  // already processed
4682       }
4683       // Reducible Phi's will be removed from the graph after split_unique_types
4684       // finishes. For now we just try to split out the SR inputs of the merge.
4685       Node* parent = n->in(1);
4686       if (reducible_merges.member(n)) {
4687         reduce_phi(n->as_Phi(), alloc_worklist, memnode_worklist);
4688 #ifdef ASSERT
4689         if (VerifyReduceAllocationMerges) {
4690           reduced_merges.push(n);
4691         }
4692 #endif
4693         continue;
4694       } else if (reducible_merges.member(parent)) {
4695         // 'n' is an user of a reducible merge (a Phi). It will be simplified as
4696         // part of reduce_merge.
4697         continue;
4698       }
4699       JavaObjectNode* jobj = unique_java_object(n);
4700       if (jobj == nullptr || jobj == phantom_obj) {
4701 #ifdef ASSERT
4702         ptnode_adr(n->_idx)->dump();
4703         assert(jobj != nullptr && jobj != phantom_obj, "escaped allocation");
4704 #endif
4705         _compile->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4706         return;
4707       } else {
4708         Node *val = get_map(jobj->idx());   // CheckCastPP node
4709         TypeNode *tn = n->as_Type();
4710         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
4711         assert(tinst != nullptr && tinst->is_known_instance() &&
4712                tinst->instance_id() == jobj->idx() , "instance type expected.");
4713 
4714         const Type *tn_type = igvn->type(tn);
4715         const TypeOopPtr *tn_t;
4716         if (tn_type->isa_narrowoop()) {
4717           tn_t = tn_type->make_ptr()->isa_oopptr();
4718         } else {
4719           tn_t = tn_type->isa_oopptr();
4720         }
4721         if (tn_t != nullptr && tinst->maybe_java_subtype_of(tn_t)) {
4722           if (tn_t->isa_aryptr()) {
4723             // Keep array properties (not flat/null-free)
4724             tinst = tinst->is_aryptr()->update_properties(tn_t->is_aryptr());
4725             if (tinst == nullptr) {
4726               continue; // Skip dead path with inconsistent properties
4727             }
4728           }
4729           if (tn_type->isa_narrowoop()) {
4730             tn_type = tinst->make_narrowoop();
4731           } else {
4732             tn_type = tinst;
4733           }
4734           igvn->hash_delete(tn);
4735           igvn->set_type(tn, tn_type);
4736           tn->set_type(tn_type);
4737           igvn->hash_insert(tn);
4738           record_for_optimizer(n);
4739         } else {
4740           assert(tn_type == TypePtr::NULL_PTR ||
4741                  (tn_t != nullptr && !tinst->maybe_java_subtype_of(tn_t)),
4742                  "unexpected type");
4743           continue; // Skip dead path with different type
4744         }
4745       }
4746     } else {
4747       DEBUG_ONLY(n->dump();)
4748       assert(false, "EA: unexpected node");
4749       continue;
4750     }
4751     // push allocation's users on appropriate worklist
4752     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4753       Node *use = n->fast_out(i);
4754       if (use->is_Mem() && use->in(MemNode::Address) == n) {
4755         // Load/store to instance's field
4756         memnode_worklist.append_if_missing(use);
4757       } else if (use->is_MemBar()) {
4758         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
4759           memnode_worklist.append_if_missing(use);
4760         }
4761       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
4762         Node* addp2 = find_second_addp(use, n);
4763         if (addp2 != nullptr) {
4764           alloc_worklist.append_if_missing(addp2);
4765         }
4766         alloc_worklist.append_if_missing(use);
4767       } else if (use->is_Phi() ||
4768                  use->is_CheckCastPP() ||
4769                  use->is_EncodeNarrowPtr() ||
4770                  use->is_DecodeNarrowPtr() ||
4771                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
4772         alloc_worklist.append_if_missing(use);
4773 #ifdef ASSERT
4774       } else if (use->is_Mem()) {
4775         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
4776       } else if (use->is_MergeMem()) {
4777         assert(mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
4778       } else if (use->is_SafePoint()) {
4779         // Look for MergeMem nodes for calls which reference unique allocation
4780         // (through CheckCastPP nodes) even for debug info.
4781         Node* m = use->in(TypeFunc::Memory);
4782         if (m->is_MergeMem()) {
4783           assert(mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
4784         }
4785       } else if (use->Opcode() == Op_EncodeISOArray) {
4786         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
4787           // EncodeISOArray overwrites destination array
4788           memnode_worklist.append_if_missing(use);
4789         }
4790       } else if (use->Opcode() == Op_Return) {
4791         // Allocation is referenced by field of returned inline type
4792         assert(_compile->tf()->returns_inline_type_as_fields(), "EA: unexpected reference by ReturnNode");
4793       } else {
4794         uint op = use->Opcode();
4795         if ((op == Op_StrCompressedCopy || op == Op_StrInflatedCopy) &&
4796             (use->in(MemNode::Memory) == n)) {
4797           // They overwrite memory edge corresponding to destination array,
4798           memnode_worklist.append_if_missing(use);
4799         } else if (!(op == Op_CmpP || op == Op_Conv2B ||
4800               op == Op_CastP2X ||
4801               op == Op_FastLock || op == Op_AryEq ||
4802               op == Op_StrComp || op == Op_CountPositives ||
4803               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
4804               op == Op_StrEquals || op == Op_VectorizedHashCode ||
4805               op == Op_StrIndexOf || op == Op_StrIndexOfChar ||
4806               op == Op_SubTypeCheck || op == Op_InlineType || op == Op_FlatArrayCheck ||
4807               op == Op_ReinterpretS2HF ||
4808               BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(use))) {
4809           n->dump();
4810           use->dump();
4811           assert(false, "EA: missing allocation reference path");
4812         }
4813 #endif
4814       }
4815     }
4816 
4817   }
4818 
4819 #ifdef ASSERT
4820   if (VerifyReduceAllocationMerges) {
4821     for (uint i = 0; i < reducible_merges.size(); i++) {
4822       Node* phi = reducible_merges.at(i);
4823 
4824       if (!reduced_merges.member(phi)) {
4825         phi->dump(2);
4826         phi->dump(-2);
4827         assert(false, "This reducible merge wasn't reduced.");
4828       }
4829 
4830       // At this point reducible Phis shouldn't have AddP users anymore; only SafePoints or Casts.
4831       for (DUIterator_Fast jmax, j = phi->fast_outs(jmax); j < jmax; j++) {
4832         Node* use = phi->fast_out(j);
4833         if (!use->is_SafePoint() && !use->is_CastPP()) {
4834           phi->dump(2);
4835           phi->dump(-2);
4836           assert(false, "Unexpected user of reducible Phi -> %d:%s:%d", use->_idx, use->Name(), use->outcnt());
4837         }
4838       }
4839     }
4840   }
4841 #endif
4842 
4843   // Go over all ArrayCopy nodes and if one of the inputs has a unique
4844   // type, record it in the ArrayCopy node so we know what memory this
4845   // node uses/modified.
4846   for (int next = 0; next < arraycopy_worklist.length(); next++) {
4847     ArrayCopyNode* ac = arraycopy_worklist.at(next);
4848     Node* dest = ac->in(ArrayCopyNode::Dest);
4849     if (dest->is_AddP()) {
4850       dest = get_addp_base(dest);
4851     }
4852     JavaObjectNode* jobj = unique_java_object(dest);
4853     if (jobj != nullptr) {
4854       Node *base = get_map(jobj->idx());
4855       if (base != nullptr) {
4856         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
4857         ac->_dest_type = base_t;
4858       }
4859     }
4860     Node* src = ac->in(ArrayCopyNode::Src);
4861     if (src->is_AddP()) {
4862       src = get_addp_base(src);
4863     }
4864     jobj = unique_java_object(src);
4865     if (jobj != nullptr) {
4866       Node* base = get_map(jobj->idx());
4867       if (base != nullptr) {
4868         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
4869         ac->_src_type = base_t;
4870       }
4871     }
4872   }
4873 
4874   // New alias types were created in split_AddP().
4875   uint new_index_end = (uint) _compile->num_alias_types();
4876 
4877   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
4878   //            compute new values for Memory inputs  (the Memory inputs are not
4879   //            actually updated until phase 4.)
4880   if (memnode_worklist.length() == 0)
4881     return;  // nothing to do
4882   while (memnode_worklist.length() != 0) {
4883     Node *n = memnode_worklist.pop();
4884     if (visited.test_set(n->_idx)) {
4885       continue;
4886     }
4887     if (n->is_Phi() || n->is_ClearArray()) {
4888       // we don't need to do anything, but the users must be pushed
4889     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
4890       // we don't need to do anything, but the users must be pushed
4891       n = n->as_MemBar()->proj_out_or_null(TypeFunc::Memory);
4892       if (n == nullptr) {
4893         continue;
4894       }
4895     } else if (n->is_CallLeaf()) {
4896       // Runtime calls with narrow memory input (no MergeMem node)
4897       // get the memory projection
4898       n = n->as_Call()->proj_out_or_null(TypeFunc::Memory);
4899       if (n == nullptr) {
4900         continue;
4901       }
4902     } else if (n->Opcode() == Op_StrInflatedCopy) {
4903       // Check direct uses of StrInflatedCopy.
4904       // It is memory type Node - no special SCMemProj node.
4905     } else if (n->Opcode() == Op_StrCompressedCopy ||
4906                n->Opcode() == Op_EncodeISOArray) {
4907       // get the memory projection
4908       n = n->find_out_with(Op_SCMemProj);
4909       assert(n != nullptr && n->Opcode() == Op_SCMemProj, "memory projection required");
4910     } else if (n->is_CallLeaf() && n->as_CallLeaf()->_name != nullptr &&
4911                strcmp(n->as_CallLeaf()->_name, "store_unknown_inline") == 0) {
4912       n = n->as_CallLeaf()->proj_out(TypeFunc::Memory);
4913     } else {
4914 #ifdef ASSERT
4915       if (!n->is_Mem()) {
4916         n->dump();
4917       }
4918       assert(n->is_Mem(), "memory node required.");
4919 #endif
4920       Node *addr = n->in(MemNode::Address);
4921       const Type *addr_t = igvn->type(addr);
4922       if (addr_t == Type::TOP) {
4923         continue;
4924       }
4925       assert (addr_t->isa_ptr() != nullptr, "pointer type required.");
4926       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
4927       assert ((uint)alias_idx < new_index_end, "wrong alias index");
4928       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
4929       if (_compile->failing()) {
4930         return;
4931       }
4932       if (mem != n->in(MemNode::Memory)) {
4933         // We delay the memory edge update since we need old one in
4934         // MergeMem code below when instances memory slices are separated.
4935         set_map(n, mem);
4936       }
4937       if (n->is_Load()) {
4938         continue;  // don't push users
4939       } else if (n->is_LoadStore()) {
4940         // get the memory projection
4941         n = n->find_out_with(Op_SCMemProj);
4942         assert(n != nullptr && n->Opcode() == Op_SCMemProj, "memory projection required");
4943       }
4944     }
4945     // push user on appropriate worklist
4946     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4947       Node *use = n->fast_out(i);
4948       if (use->is_Phi() || use->is_ClearArray()) {
4949         memnode_worklist.append_if_missing(use);
4950       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
4951         memnode_worklist.append_if_missing(use);
4952       } else if (use->is_MemBar() || use->is_CallLeaf()) {
4953         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
4954           memnode_worklist.append_if_missing(use);
4955         }
4956 #ifdef ASSERT
4957       } else if (use->is_Mem()) {
4958         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
4959       } else if (use->is_MergeMem()) {
4960         assert(mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
4961       } else if (use->Opcode() == Op_EncodeISOArray) {
4962         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
4963           // EncodeISOArray overwrites destination array
4964           memnode_worklist.append_if_missing(use);
4965         }
4966       } else if (use->is_CallLeaf() && use->as_CallLeaf()->_name != nullptr &&
4967                  strcmp(use->as_CallLeaf()->_name, "store_unknown_inline") == 0) {
4968         // store_unknown_inline overwrites destination array
4969         memnode_worklist.append_if_missing(use);
4970       } else {
4971         uint op = use->Opcode();
4972         if ((use->in(MemNode::Memory) == n) &&
4973             (op == Op_StrCompressedCopy || op == Op_StrInflatedCopy)) {
4974           // They overwrite memory edge corresponding to destination array,
4975           memnode_worklist.append_if_missing(use);
4976         } else if (!(BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(use) ||
4977               op == Op_AryEq || op == Op_StrComp || op == Op_CountPositives ||
4978               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy || op == Op_VectorizedHashCode ||
4979               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar || op == Op_FlatArrayCheck)) {
4980           n->dump();
4981           use->dump();
4982           assert(false, "EA: missing memory path");
4983         }
4984 #endif
4985       }
4986     }
4987   }
4988 
4989   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
4990   //            Walk each memory slice moving the first node encountered of each
4991   //            instance type to the input corresponding to its alias index.
4992   uint length = mergemem_worklist.length();
4993   for( uint next = 0; next < length; ++next ) {
4994     MergeMemNode* nmm = mergemem_worklist.at(next);
4995     assert(!visited.test_set(nmm->_idx), "should not be visited before");
4996     // Note: we don't want to use MergeMemStream here because we only want to
4997     // scan inputs which exist at the start, not ones we add during processing.
4998     // Note 2: MergeMem may already contains instance memory slices added
4999     // during find_inst_mem() call when memory nodes were processed above.
5000     igvn->hash_delete(nmm);
5001     uint nslices = MIN2(nmm->req(), new_index_start);
5002     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
5003       Node* mem = nmm->in(i);
5004       Node* cur = nullptr;
5005       if (mem == nullptr || mem->is_top()) {
5006         continue;
5007       }
5008       // First, update mergemem by moving memory nodes to corresponding slices
5009       // if their type became more precise since this mergemem was created.
5010       while (mem->is_Mem()) {
5011         const Type *at = igvn->type(mem->in(MemNode::Address));
5012         if (at != Type::TOP) {
5013           assert (at->isa_ptr() != nullptr, "pointer type required.");
5014           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
5015           if (idx == i) {
5016             if (cur == nullptr) {
5017               cur = mem;
5018             }
5019           } else {
5020             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
5021               nmm->set_memory_at(idx, mem);
5022             }
5023           }
5024         }
5025         mem = mem->in(MemNode::Memory);
5026       }
5027       nmm->set_memory_at(i, (cur != nullptr) ? cur : mem);
5028       // Find any instance of the current type if we haven't encountered
5029       // already a memory slice of the instance along the memory chain.
5030       for (uint ni = new_index_start; ni < new_index_end; ni++) {
5031         if((uint)_compile->get_general_index(ni) == i) {
5032           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
5033           if (nmm->is_empty_memory(m)) {
5034             Node* result = find_inst_mem(mem, ni, orig_phis);
5035             if (_compile->failing()) {
5036               return;
5037             }
5038             nmm->set_memory_at(ni, result);
5039           }
5040         }
5041       }
5042     }
5043     // Find the rest of instances values
5044     for (uint ni = new_index_start; ni < new_index_end; ni++) {
5045       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
5046       Node* result = step_through_mergemem(nmm, ni, tinst);
5047       if (result == nmm->base_memory()) {
5048         // Didn't find instance memory, search through general slice recursively.
5049         result = nmm->memory_at(_compile->get_general_index(ni));
5050         result = find_inst_mem(result, ni, orig_phis);
5051         if (_compile->failing()) {
5052           return;
5053         }
5054         nmm->set_memory_at(ni, result);
5055       }
5056     }
5057 
5058     // If we have crossed the 3/4 point of max node limit it's too risky
5059     // to continue with EA/SR because we might hit the max node limit.
5060     if (_compile->live_nodes() >= _compile->max_node_limit() * 0.75) {
5061       if (_compile->do_reduce_allocation_merges()) {
5062         _compile->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
5063       } else if (_invocation > 0) {
5064         _compile->record_failure(C2Compiler::retry_no_iterative_escape_analysis());
5065       } else {
5066         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
5067       }
5068       return;
5069     }
5070 
5071     igvn->hash_insert(nmm);
5072     record_for_optimizer(nmm);
5073   }
5074 
5075   //  Phase 4:  Update the inputs of non-instance memory Phis and
5076   //            the Memory input of memnodes
5077   // First update the inputs of any non-instance Phi's from
5078   // which we split out an instance Phi.  Note we don't have
5079   // to recursively process Phi's encountered on the input memory
5080   // chains as is done in split_memory_phi() since they will
5081   // also be processed here.
5082   for (int j = 0; j < orig_phis.length(); j++) {
5083     PhiNode *phi = orig_phis.at(j);
5084     int alias_idx = _compile->get_alias_index(phi->adr_type());
5085     igvn->hash_delete(phi);
5086     for (uint i = 1; i < phi->req(); i++) {
5087       Node *mem = phi->in(i);
5088       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
5089       if (_compile->failing()) {
5090         return;
5091       }
5092       if (mem != new_mem) {
5093         phi->set_req(i, new_mem);
5094       }
5095     }
5096     igvn->hash_insert(phi);
5097     record_for_optimizer(phi);
5098   }
5099 
5100   // Update the memory inputs of MemNodes with the value we computed
5101   // in Phase 2 and move stores memory users to corresponding memory slices.
5102   // Disable memory split verification code until the fix for 6984348.
5103   // Currently it produces false negative results since it does not cover all cases.
5104 #if 0 // ifdef ASSERT
5105   visited.Reset();
5106   Node_Stack old_mems(arena, _compile->unique() >> 2);
5107 #endif
5108   for (uint i = 0; i < ideal_nodes.size(); i++) {
5109     Node*    n = ideal_nodes.at(i);
5110     Node* nmem = get_map(n->_idx);
5111     assert(nmem != nullptr, "sanity");
5112     if (n->is_Mem()) {
5113 #if 0 // ifdef ASSERT
5114       Node* old_mem = n->in(MemNode::Memory);
5115       if (!visited.test_set(old_mem->_idx)) {
5116         old_mems.push(old_mem, old_mem->outcnt());
5117       }
5118 #endif
5119       assert(n->in(MemNode::Memory) != nmem, "sanity");
5120       if (!n->is_Load()) {
5121         // Move memory users of a store first.
5122         move_inst_mem(n, orig_phis);
5123       }
5124       // Now update memory input
5125       igvn->hash_delete(n);
5126       n->set_req(MemNode::Memory, nmem);
5127       igvn->hash_insert(n);
5128       record_for_optimizer(n);
5129     } else {
5130       assert(n->is_Allocate() || n->is_CheckCastPP() ||
5131              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
5132     }
5133   }
5134 #if 0 // ifdef ASSERT
5135   // Verify that memory was split correctly
5136   while (old_mems.is_nonempty()) {
5137     Node* old_mem = old_mems.node();
5138     uint  old_cnt = old_mems.index();
5139     old_mems.pop();
5140     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
5141   }
5142 #endif
5143 }
5144 
5145 #ifndef PRODUCT
5146 int ConnectionGraph::_no_escape_counter = 0;
5147 int ConnectionGraph::_arg_escape_counter = 0;
5148 int ConnectionGraph::_global_escape_counter = 0;
5149 
5150 static const char *node_type_names[] = {
5151   "UnknownType",
5152   "JavaObject",
5153   "LocalVar",
5154   "Field",
5155   "Arraycopy"
5156 };
5157 
5158 static const char *esc_names[] = {
5159   "UnknownEscape",
5160   "NoEscape",
5161   "ArgEscape",
5162   "GlobalEscape"
5163 };
5164 
5165 void PointsToNode::dump_header(bool print_state, outputStream* out) const {
5166   NodeType nt = node_type();
5167   out->print("%s(%d) ", node_type_names[(int) nt], _pidx);
5168   if (print_state) {
5169     EscapeState es = escape_state();
5170     EscapeState fields_es = fields_escape_state();
5171     out->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
5172     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable()) {
5173       out->print("NSR ");
5174     }
5175   }
5176 }
5177 
5178 void PointsToNode::dump(bool print_state, outputStream* out, bool newline) const {
5179   dump_header(print_state, out);
5180   if (is_Field()) {
5181     FieldNode* f = (FieldNode*)this;
5182     if (f->is_oop()) {
5183       out->print("oop ");
5184     }
5185     if (f->offset() > 0) {
5186       out->print("+%d ", f->offset());
5187     }
5188     out->print("(");
5189     for (BaseIterator i(f); i.has_next(); i.next()) {
5190       PointsToNode* b = i.get();
5191       out->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
5192     }
5193     out->print(" )");
5194   }
5195   out->print("[");
5196   for (EdgeIterator i(this); i.has_next(); i.next()) {
5197     PointsToNode* e = i.get();
5198     out->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
5199   }
5200   out->print(" [");
5201   for (UseIterator i(this); i.has_next(); i.next()) {
5202     PointsToNode* u = i.get();
5203     bool is_base = false;
5204     if (PointsToNode::is_base_use(u)) {
5205       is_base = true;
5206       u = PointsToNode::get_use_node(u)->as_Field();
5207     }
5208     out->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
5209   }
5210   out->print(" ]]  ");
5211   if (_node == nullptr) {
5212     out->print("<null>%s", newline ? "\n" : "");
5213   } else {
5214     _node->dump(newline ? "\n" : "", false, out);
5215   }
5216 }
5217 
5218 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
5219   bool first = true;
5220   int ptnodes_length = ptnodes_worklist.length();
5221   for (int i = 0; i < ptnodes_length; i++) {
5222     PointsToNode *ptn = ptnodes_worklist.at(i);
5223     if (ptn == nullptr || !ptn->is_JavaObject()) {
5224       continue;
5225     }
5226     PointsToNode::EscapeState es = ptn->escape_state();
5227     if ((es != PointsToNode::NoEscape) && !Verbose) {
5228       continue;
5229     }
5230     Node* n = ptn->ideal_node();
5231     if (n->is_Allocate() || (n->is_CallStaticJava() &&
5232                              n->as_CallStaticJava()->is_boxing_method())) {
5233       if (first) {
5234         tty->cr();
5235         tty->print("======== Connection graph for ");
5236         _compile->method()->print_short_name();
5237         tty->cr();
5238         tty->print_cr("invocation #%d: %d iterations and %f sec to build connection graph with %d nodes and worklist size %d",
5239                       _invocation, _build_iterations, _build_time, nodes_size(), ptnodes_worklist.length());
5240         tty->cr();
5241         first = false;
5242       }
5243       ptn->dump();
5244       // Print all locals and fields which reference this allocation
5245       for (UseIterator j(ptn); j.has_next(); j.next()) {
5246         PointsToNode* use = j.get();
5247         if (use->is_LocalVar()) {
5248           use->dump(Verbose);
5249         } else if (Verbose) {
5250           use->dump();
5251         }
5252       }
5253       tty->cr();
5254     }
5255   }
5256 }
5257 
5258 void ConnectionGraph::print_statistics() {
5259   tty->print_cr("No escape = %d, Arg escape = %d, Global escape = %d", AtomicAccess::load(&_no_escape_counter), AtomicAccess::load(&_arg_escape_counter), AtomicAccess::load(&_global_escape_counter));
5260 }
5261 
5262 void ConnectionGraph::escape_state_statistics(GrowableArray<JavaObjectNode*>& java_objects_worklist) {
5263   if (!PrintOptoStatistics || (_invocation > 0)) { // Collect data only for the first invocation
5264     return;
5265   }
5266   for (int next = 0; next < java_objects_worklist.length(); ++next) {
5267     JavaObjectNode* ptn = java_objects_worklist.at(next);
5268     if (ptn->ideal_node()->is_Allocate()) {
5269       if (ptn->escape_state() == PointsToNode::NoEscape) {
5270         AtomicAccess::inc(&ConnectionGraph::_no_escape_counter);
5271       } else if (ptn->escape_state() == PointsToNode::ArgEscape) {
5272         AtomicAccess::inc(&ConnectionGraph::_arg_escape_counter);
5273       } else if (ptn->escape_state() == PointsToNode::GlobalEscape) {
5274         AtomicAccess::inc(&ConnectionGraph::_global_escape_counter);
5275       } else {
5276         assert(false, "Unexpected Escape State");
5277       }
5278     }
5279   }
5280 }
5281 
5282 void ConnectionGraph::trace_es_update_helper(PointsToNode* ptn, PointsToNode::EscapeState es, bool fields, const char* reason) const {
5283   if (_compile->directive()->TraceEscapeAnalysisOption) {
5284     assert(ptn != nullptr, "should not be null");
5285     assert(reason != nullptr, "should not be null");
5286     ptn->dump_header(true);
5287     PointsToNode::EscapeState new_es = fields ? ptn->escape_state() : es;
5288     PointsToNode::EscapeState new_fields_es = fields ? es : ptn->fields_escape_state();
5289     tty->print_cr("-> %s(%s) %s", esc_names[(int)new_es], esc_names[(int)new_fields_es], reason);
5290   }
5291 }
5292 
5293 const char* ConnectionGraph::trace_propagate_message(PointsToNode* from) const {
5294   if (_compile->directive()->TraceEscapeAnalysisOption) {
5295     stringStream ss;
5296     ss.print("propagated from: ");
5297     from->dump(true, &ss, false);
5298     return ss.as_string();
5299   } else {
5300     return nullptr;
5301   }
5302 }
5303 
5304 const char* ConnectionGraph::trace_arg_escape_message(CallNode* call) const {
5305   if (_compile->directive()->TraceEscapeAnalysisOption) {
5306     stringStream ss;
5307     ss.print("escapes as arg to:");
5308     call->dump("", false, &ss);
5309     return ss.as_string();
5310   } else {
5311     return nullptr;
5312   }
5313 }
5314 
5315 const char* ConnectionGraph::trace_merged_message(PointsToNode* other) const {
5316   if (_compile->directive()->TraceEscapeAnalysisOption) {
5317     stringStream ss;
5318     ss.print("is merged with other object: ");
5319     other->dump_header(true, &ss);
5320     return ss.as_string();
5321   } else {
5322     return nullptr;
5323   }
5324 }
5325 
5326 #endif
5327 
5328 void ConnectionGraph::record_for_optimizer(Node *n) {
5329   _igvn->_worklist.push(n);
5330   _igvn->add_users_to_worklist(n);
5331 }
--- EOF ---