1 /*
   2  * Copyright (c) 2005, 2026, 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   NOT_PRODUCT(if (C->should_print_igv(/* Any level */ 1)) C->igv_printer()->set_congraph(congraph);)
 120   // Perform escape analysis
 121   if (congraph->compute_escape()) {
 122     // There are non escaping objects.
 123     C->set_congraph(congraph);
 124   }
 125   NOT_PRODUCT(if (C->should_print_igv(/* Any level */ 1)) C->igv_printer()->set_congraph(nullptr);)
 126   // Cleanup.
 127   if (oop_null->outcnt() == 0) {
 128     igvn->hash_delete(oop_null);
 129   }
 130   if (noop_null->outcnt() == 0) {
 131     igvn->hash_delete(noop_null);
 132   }
 133 
 134   C->print_method(PHASE_AFTER_EA, 2);
 135 }
 136 
 137 bool ConnectionGraph::compute_escape() {
 138   Compile* C = _compile;
 139   PhaseGVN* igvn = _igvn;
 140 
 141   // Worklists used by EA.
 142   Unique_Node_List delayed_worklist;
 143   Unique_Node_List reducible_merges;
 144   GrowableArray<Node*> alloc_worklist;
 145   GrowableArray<Node*> ptr_cmp_worklist;
 146   GrowableArray<MemBarStoreStoreNode*> storestore_worklist;
 147   GrowableArray<ArrayCopyNode*>  arraycopy_worklist;
 148   GrowableArray<PointsToNode*>   ptnodes_worklist;
 149   GrowableArray<JavaObjectNode*> java_objects_worklist;
 150   GrowableArray<JavaObjectNode*> non_escaped_allocs_worklist;
 151   GrowableArray<FieldNode*>      oop_fields_worklist;
 152   GrowableArray<SafePointNode*>  sfn_worklist;
 153   GrowableArray<MergeMemNode*>   mergemem_worklist;
 154   DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
 155 
 156   { Compile::TracePhase tp(Phase::_t_connectionGraph);
 157 
 158   // 1. Populate Connection Graph (CG) with PointsTo nodes.
 159   ideal_nodes.map(C->live_nodes(), nullptr);  // preallocate space
 160   // Initialize worklist
 161   if (C->root() != nullptr) {
 162     ideal_nodes.push(C->root());
 163   }
 164   // Processed ideal nodes are unique on ideal_nodes list
 165   // but several ideal nodes are mapped to the phantom_obj.
 166   // To avoid duplicated entries on the following worklists
 167   // add the phantom_obj only once to them.
 168   ptnodes_worklist.append(phantom_obj);
 169   java_objects_worklist.append(phantom_obj);
 170   for( uint next = 0; next < ideal_nodes.size(); ++next ) {
 171     Node* n = ideal_nodes.at(next);
 172     if ((n->Opcode() == Op_LoadX || n->Opcode() == Op_StoreX) &&
 173         !n->in(MemNode::Address)->is_AddP() &&
 174         _igvn->type(n->in(MemNode::Address))->isa_oopptr()) {
 175       // Load/Store at mark work address is at offset 0 so has no AddP which confuses EA
 176       Node* addp = AddPNode::make_with_base(n->in(MemNode::Address), n->in(MemNode::Address), _igvn->MakeConX(0));
 177       _igvn->register_new_node_with_optimizer(addp);
 178       _igvn->replace_input_of(n, MemNode::Address, addp);
 179       ideal_nodes.push(addp);
 180       _nodes.at_put_grow(addp->_idx, nullptr, nullptr);
 181     }
 182     // Create PointsTo nodes and add them to Connection Graph. Called
 183     // only once per ideal node since ideal_nodes is Unique_Node list.
 184     add_node_to_connection_graph(n, &delayed_worklist);
 185     PointsToNode* ptn = ptnode_adr(n->_idx);
 186     if (ptn != nullptr && ptn != phantom_obj) {
 187       ptnodes_worklist.append(ptn);
 188       if (ptn->is_JavaObject()) {
 189         java_objects_worklist.append(ptn->as_JavaObject());
 190         if ((n->is_Allocate() || n->is_CallStaticJava()) &&
 191             (ptn->escape_state() < PointsToNode::GlobalEscape)) {
 192           // Only allocations and java static calls results are interesting.
 193           non_escaped_allocs_worklist.append(ptn->as_JavaObject());
 194         }
 195       } else if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
 196         oop_fields_worklist.append(ptn->as_Field());
 197       }
 198     }
 199     // Collect some interesting nodes for further use.
 200     switch (n->Opcode()) {
 201       case Op_MergeMem:
 202         // Collect all MergeMem nodes to add memory slices for
 203         // scalar replaceable objects in split_unique_types().
 204         mergemem_worklist.append(n->as_MergeMem());
 205         break;
 206       case Op_CmpP:
 207       case Op_CmpN:
 208         // Collect compare pointers nodes.
 209         if (OptimizePtrCompare) {
 210           ptr_cmp_worklist.append(n);
 211         }
 212         break;
 213       case Op_MemBarStoreStore:
 214         // Collect all MemBarStoreStore nodes so that depending on the
 215         // escape status of the associated Allocate node some of them
 216         // may be eliminated.
 217         if (!UseStoreStoreForCtor || n->req() > MemBarNode::Precedent) {
 218           storestore_worklist.append(n->as_MemBarStoreStore());
 219         }
 220         // If MemBarStoreStore has a precedent edge add it to the worklist (like MemBarRelease)
 221       case Op_MemBarRelease:
 222         if (n->req() > MemBarNode::Precedent) {
 223           record_for_optimizer(n);
 224         }
 225         break;
 226 #ifdef ASSERT
 227       case Op_AddP:
 228         // Collect address nodes for graph verification.
 229         addp_worklist.append(n);
 230         break;
 231 #endif
 232       case Op_ArrayCopy:
 233         // Keep a list of ArrayCopy nodes so if one of its input is non
 234         // escaping, we can record a unique type
 235         arraycopy_worklist.append(n->as_ArrayCopy());
 236         break;
 237       default:
 238         // not interested now, ignore...
 239         break;
 240     }
 241     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 242       Node* m = n->fast_out(i);   // Get user
 243       ideal_nodes.push(m);
 244     }
 245     if (n->is_SafePoint()) {
 246       sfn_worklist.append(n->as_SafePoint());
 247     }
 248   }
 249 
 250 #ifndef PRODUCT
 251   if (_compile->directive()->TraceEscapeAnalysisOption) {
 252     tty->print("+++++ Initial worklist for ");
 253     _compile->method()->print_name();
 254     tty->print_cr(" (ea_inv=%d)", _invocation);
 255     for (int i = 0; i < ptnodes_worklist.length(); i++) {
 256       PointsToNode* ptn = ptnodes_worklist.at(i);
 257       ptn->dump();
 258     }
 259     tty->print_cr("+++++ Calculating escape states and scalar replaceability");
 260   }
 261 #endif
 262 
 263   if (non_escaped_allocs_worklist.length() == 0) {
 264     _collecting = false;
 265     NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 266     return false; // Nothing to do.
 267   }
 268   // Add final simple edges to graph.
 269   while(delayed_worklist.size() > 0) {
 270     Node* n = delayed_worklist.pop();
 271     add_final_edges(n);
 272   }
 273 
 274 #ifdef ASSERT
 275   if (VerifyConnectionGraph) {
 276     // Verify that no new simple edges could be created and all
 277     // local vars has edges.
 278     _verify = true;
 279     int ptnodes_length = ptnodes_worklist.length();
 280     for (int next = 0; next < ptnodes_length; ++next) {
 281       PointsToNode* ptn = ptnodes_worklist.at(next);
 282       add_final_edges(ptn->ideal_node());
 283       if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
 284         ptn->dump();
 285         assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
 286       }
 287     }
 288     _verify = false;
 289   }
 290 #endif
 291   // Bytecode analyzer BCEscapeAnalyzer, used for Call nodes
 292   // processing, calls to CI to resolve symbols (types, fields, methods)
 293   // referenced in bytecode. During symbol resolution VM may throw
 294   // an exception which CI cleans and converts to compilation failure.
 295   if (C->failing()) {
 296     NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 297     return false;
 298   }
 299 
 300   _compile->print_method(PHASE_EA_AFTER_INITIAL_CONGRAPH, 4);
 301 
 302   // 2. Finish Graph construction by propagating references to all
 303   //    java objects through graph.
 304   if (!complete_connection_graph(ptnodes_worklist, non_escaped_allocs_worklist,
 305                                  java_objects_worklist, oop_fields_worklist)) {
 306     // All objects escaped or hit time or iterations limits.
 307     _collecting = false;
 308     NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 309     return false;
 310   }
 311 
 312   _compile->print_method(PHASE_EA_AFTER_COMPLETE_CONGRAPH, 4);
 313 
 314   // 3. Adjust scalar_replaceable state of nonescaping objects and push
 315   //    scalar replaceable allocations on alloc_worklist for processing
 316   //    in split_unique_types().
 317   GrowableArray<JavaObjectNode*> jobj_worklist;
 318   int non_escaped_length = non_escaped_allocs_worklist.length();
 319   bool found_nsr_alloc = false;
 320   for (int next = 0; next < non_escaped_length; next++) {
 321     JavaObjectNode* ptn = non_escaped_allocs_worklist.at(next);
 322     bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
 323     Node* n = ptn->ideal_node();
 324     if (n->is_Allocate()) {
 325       n->as_Allocate()->_is_non_escaping = noescape;
 326     }
 327     if (noescape && ptn->scalar_replaceable()) {
 328       adjust_scalar_replaceable_state(ptn, reducible_merges);
 329       if (ptn->scalar_replaceable()) {
 330         jobj_worklist.push(ptn);
 331       } else {
 332         found_nsr_alloc = true;
 333       }
 334     }
 335     _compile->print_method(PHASE_EA_ADJUST_SCALAR_REPLACEABLE_ITER, 6, n);
 336   }
 337 
 338   // Propagate NSR (Not Scalar Replaceable) state.
 339   if (found_nsr_alloc) {
 340     find_scalar_replaceable_allocs(jobj_worklist, reducible_merges);
 341   }
 342 
 343   // alloc_worklist will be processed in reverse push order.
 344   // Therefore the reducible Phis will be processed for last and that's what we
 345   // want because by then the scalarizable inputs of the merge will already have
 346   // an unique instance type.
 347   for (uint i = 0; i < reducible_merges.size(); i++ ) {
 348     Node* n = reducible_merges.at(i);
 349     alloc_worklist.append(n);
 350   }
 351 
 352   for (int next = 0; next < jobj_worklist.length(); ++next) {
 353     JavaObjectNode* jobj = jobj_worklist.at(next);
 354     if (jobj->scalar_replaceable()) {
 355       alloc_worklist.append(jobj->ideal_node());
 356     }
 357   }
 358 
 359 #ifdef ASSERT
 360   if (VerifyConnectionGraph) {
 361     // Verify that graph is complete - no new edges could be added or needed.
 362     verify_connection_graph(ptnodes_worklist, non_escaped_allocs_worklist,
 363                             java_objects_worklist, addp_worklist);
 364   }
 365   assert(C->unique() == nodes_size(), "no new ideal nodes should be added during ConnectionGraph build");
 366   assert(null_obj->escape_state() == PointsToNode::NoEscape &&
 367          null_obj->edge_count() == 0 &&
 368          !null_obj->arraycopy_src() &&
 369          !null_obj->arraycopy_dst(), "sanity");
 370 #endif
 371 
 372   _collecting = false;
 373 
 374   _compile->print_method(PHASE_EA_AFTER_PROPAGATE_NSR, 4);
 375   } // TracePhase t3("connectionGraph")
 376 
 377   // 4. Optimize ideal graph based on EA information.
 378   bool has_non_escaping_obj = (non_escaped_allocs_worklist.length() > 0);
 379   if (has_non_escaping_obj) {
 380     optimize_ideal_graph(ptr_cmp_worklist, storestore_worklist);
 381   }
 382 
 383 #ifndef PRODUCT
 384   if (PrintEscapeAnalysis) {
 385     dump(ptnodes_worklist); // Dump ConnectionGraph
 386   }
 387 #endif
 388 
 389 #ifdef ASSERT
 390   if (VerifyConnectionGraph) {
 391     int alloc_length = alloc_worklist.length();
 392     for (int next = 0; next < alloc_length; ++next) {
 393       Node* n = alloc_worklist.at(next);
 394       PointsToNode* ptn = ptnode_adr(n->_idx);
 395       assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
 396     }
 397   }
 398 
 399   if (VerifyReduceAllocationMerges) {
 400     for (uint i = 0; i < reducible_merges.size(); i++ ) {
 401       Node* n = reducible_merges.at(i);
 402       if (!can_reduce_phi(n->as_Phi())) {
 403         TraceReduceAllocationMerges = true;
 404         n->dump(2);
 405         n->dump(-2);
 406         assert(can_reduce_phi(n->as_Phi()), "Sanity: previous reducible Phi is no longer reducible before SUT.");
 407       }
 408     }
 409   }
 410 #endif
 411 
 412   _compile->print_method(PHASE_EA_AFTER_GRAPH_OPTIMIZATION, 4);
 413 
 414   // 5. Separate memory graph for scalar replaceable allcations.
 415   bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
 416   if (has_scalar_replaceable_candidates && EliminateAllocations) {
 417     assert(C->do_aliasing(), "Aliasing should be enabled");
 418     // Now use the escape information to create unique types for
 419     // scalar replaceable objects.
 420     split_unique_types(alloc_worklist, arraycopy_worklist, mergemem_worklist, reducible_merges);
 421     if (C->failing()) {
 422       NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 423       return false;
 424     }
 425 
 426 #ifdef ASSERT
 427   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
 428     tty->print("=== No allocations eliminated for ");
 429     C->method()->print_short_name();
 430     if (!EliminateAllocations) {
 431       tty->print(" since EliminateAllocations is off ===");
 432     } else if(!has_scalar_replaceable_candidates) {
 433       tty->print(" since there are no scalar replaceable candidates ===");
 434     }
 435     tty->cr();
 436 #endif
 437   }
 438 
 439   // 6. Expand flat accesses if the object does not escape. This adds nodes to
 440   // the graph, so it has to be after split_unique_types. This expands atomic
 441   // mismatched accesses (though encapsulated in LoadFlats and StoreFlats) into
 442   // non-mismatched accesses, so it is better before reduce allocation merges.
 443   if (has_non_escaping_obj) {
 444     optimize_flat_accesses(sfn_worklist);
 445   }
 446 
 447   _compile->print_method(PHASE_EA_AFTER_SPLIT_UNIQUE_TYPES, 4);
 448 
 449   // 7. Reduce allocation merges used as debug information. This is done after
 450   // split_unique_types because the methods used to create SafePointScalarObject
 451   // need to traverse the memory graph to find values for object fields. We also
 452   // set to null the scalarized inputs of reducible Phis so that the Allocate
 453   // that they point can be later scalar replaced.
 454   bool delay = _igvn->delay_transform();
 455   _igvn->set_delay_transform(true);
 456   for (uint i = 0; i < reducible_merges.size(); i++) {
 457     Node* n = reducible_merges.at(i);
 458     if (n->outcnt() > 0) {
 459       if (!reduce_phi_on_safepoints(n->as_Phi())) {
 460         NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 461         C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
 462         return false;
 463       }
 464 
 465       // Now we set the scalar replaceable inputs of ophi to null, which is
 466       // the last piece that would prevent it from being scalar replaceable.
 467       reset_scalar_replaceable_entries(n->as_Phi());
 468     }
 469   }
 470   _igvn->set_delay_transform(delay);
 471 
 472   // Annotate at safepoints if they have <= ArgEscape objects in their scope and at
 473   // java calls if they pass ArgEscape objects as parameters.
 474   if (has_non_escaping_obj &&
 475       (C->env()->should_retain_local_variables() ||
 476        C->env()->jvmti_can_get_owned_monitor_info() ||
 477        C->env()->jvmti_can_walk_any_space() ||
 478        DeoptimizeObjectsALot)) {
 479     int sfn_length = sfn_worklist.length();
 480     for (int next = 0; next < sfn_length; next++) {
 481       SafePointNode* sfn = sfn_worklist.at(next);
 482       sfn->set_has_ea_local_in_scope(has_ea_local_in_scope(sfn));
 483       if (sfn->is_CallJava()) {
 484         CallJavaNode* call = sfn->as_CallJava();
 485         call->set_arg_escape(has_arg_escape(call));
 486       }
 487     }
 488   }
 489 
 490   _compile->print_method(PHASE_EA_AFTER_REDUCE_PHI_ON_SAFEPOINTS, 4);
 491 
 492   NOT_PRODUCT(escape_state_statistics(java_objects_worklist);)
 493   return has_non_escaping_obj;
 494 }
 495 
 496 // Check if it's profitable to reduce the Phi passed as parameter.  Returns true
 497 // if at least one scalar replaceable allocation participates in the merge.
 498 bool ConnectionGraph::can_reduce_phi_check_inputs(PhiNode* ophi) const {
 499   bool found_sr_allocate = false;
 500 
 501   for (uint i = 1; i < ophi->req(); i++) {
 502     JavaObjectNode* ptn = unique_java_object(ophi->in(i));
 503     if (ptn != nullptr && ptn->scalar_replaceable()) {
 504       AllocateNode* alloc = ptn->ideal_node()->as_Allocate();
 505 
 506       // Don't handle arrays.
 507       if (alloc->Opcode() != Op_Allocate) {
 508         assert(alloc->Opcode() == Op_AllocateArray, "Unexpected type of allocation.");
 509         continue;
 510       }
 511 
 512       if (PhaseMacroExpand::can_eliminate_allocation(_igvn, alloc, nullptr)) {
 513         found_sr_allocate = true;
 514       } else {
 515         NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("%dth input of Phi %d is SR but can't be eliminated.", i, ophi->_idx);)
 516         ptn->set_scalar_replaceable(false);
 517       }
 518     }
 519   }
 520 
 521   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);)
 522   return found_sr_allocate;
 523 }
 524 
 525 // We can reduce the Cmp if it's a comparison between the Phi and a constant.
 526 // I require the 'other' input to be a constant so that I can move the Cmp
 527 // around safely.
 528 bool ConnectionGraph::can_reduce_cmp(Node* n, Node* cmp) const {
 529   assert(cmp->Opcode() == Op_CmpP || cmp->Opcode() == Op_CmpN, "not expected node: %s", cmp->Name());
 530   Node* left = cmp->in(1);
 531   Node* right = cmp->in(2);
 532 
 533   return (left == n || right == n) &&
 534          (left->is_Con() || right->is_Con()) &&
 535          cmp->outcnt() == 1;
 536 }
 537 
 538 // We are going to check if any of the SafePointScalarMerge entries
 539 // in the SafePoint reference the Phi that we are checking.
 540 bool ConnectionGraph::has_been_reduced(PhiNode* n, SafePointNode* sfpt) const {
 541   JVMState *jvms = sfpt->jvms();
 542 
 543   for (uint i = jvms->debug_start(); i < jvms->debug_end(); i++) {
 544     Node* sfpt_in = sfpt->in(i);
 545     if (sfpt_in->is_SafePointScalarMerge()) {
 546       SafePointScalarMergeNode* smerge = sfpt_in->as_SafePointScalarMerge();
 547       Node* nsr_ptr = sfpt->in(smerge->merge_pointer_idx(jvms));
 548       if (nsr_ptr == n) {
 549         return true;
 550       }
 551     }
 552   }
 553 
 554   return false;
 555 }
 556 
 557 // Check if we are able to untangle the merge. The following patterns are
 558 // supported:
 559 //  - Phi -> SafePoints
 560 //  - Phi -> CmpP/N
 561 //  - Phi -> AddP -> Load
 562 //  - Phi -> CastPP -> SafePoints
 563 //  - Phi -> CastPP -> AddP -> Load
 564 bool ConnectionGraph::can_reduce_check_users(Node* n, uint nesting) const {
 565   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 566     Node* use = n->fast_out(i);
 567 
 568     if (use->is_SafePoint()) {
 569       if (use->is_Call() && use->as_Call()->has_non_debug_use(n)) {
 570         NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. Call has non_debug_use().", n->_idx, _invocation);)
 571         return false;
 572       } else if (has_been_reduced(n->is_Phi() ? n->as_Phi() : n->as_CastPP()->in(1)->as_Phi(), use->as_SafePoint())) {
 573         NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Can NOT reduce Phi %d on invocation %d. It has already been reduced.", n->_idx, _invocation);)
 574         return false;
 575       }
 576     } else if (use->is_AddP()) {
 577       Node* addp = use;
 578       for (DUIterator_Fast jmax, j = addp->fast_outs(jmax); j < jmax; j++) {
 579         Node* use_use = addp->fast_out(j);
 580         const Type* load_type = _igvn->type(use_use);
 581 
 582         if (!use_use->is_Load() || !use_use->as_Load()->can_split_through_phi_base(_igvn)) {
 583           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());)
 584           return false;
 585         } else if (load_type->isa_narrowklass() || load_type->isa_klassptr()) {
 586           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());)
 587           return false;
 588         }
 589       }
 590     } else if (nesting > 0) {
 591       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);)
 592       return false;
 593     } else if (use->is_CastPP()) {
 594       const Type* cast_t = _igvn->type(use);
 595       if (cast_t == nullptr || cast_t->make_ptr()->isa_instptr() == nullptr) {
 596 #ifndef PRODUCT
 597         if (TraceReduceAllocationMerges) {
 598           tty->print_cr("Can NOT reduce Phi %d on invocation %d. CastPP is not to an instance.", n->_idx, _invocation);
 599           use->dump();
 600         }
 601 #endif
 602         return false;
 603       }
 604 
 605       bool is_trivial_control = use->in(0) == nullptr || use->in(0) == n->in(0);
 606       if (!is_trivial_control) {
 607         // If it's not a trivial control then we check if we can reduce the
 608         // CmpP/N used by the If controlling the cast.
 609         if (use->in(0)->is_IfTrue() || use->in(0)->is_IfFalse()) {
 610           Node* iff = use->in(0)->in(0);
 611           // We may have an OpaqueConstantBool node between If and Bool nodes. But we could also have a sub class of IfNode,
 612           // for example, an OuterStripMinedLoopEnd or a Parse Predicate. Bail out in all these cases.
 613           bool can_reduce = (iff->Opcode() == Op_If) && iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp();
 614           if (can_reduce) {
 615             Node* iff_cmp = iff->in(1)->in(1);
 616             int opc = iff_cmp->Opcode();
 617             can_reduce = (opc == Op_CmpP || opc == Op_CmpN) && can_reduce_cmp(n, iff_cmp);
 618           }
 619           if (!can_reduce) {
 620 #ifndef PRODUCT
 621             if (TraceReduceAllocationMerges) {
 622               tty->print_cr("Can NOT reduce Phi %d on invocation %d. CastPP %d doesn't have simple control.", n->_idx, _invocation, use->_idx);
 623               n->dump(5);
 624             }
 625 #endif
 626             return false;
 627           }
 628         }
 629       }
 630 
 631       if (!can_reduce_check_users(use, nesting+1)) {
 632         return false;
 633       }
 634     } else if (use->Opcode() == Op_CmpP || use->Opcode() == Op_CmpN) {
 635       if (!can_reduce_cmp(n, use)) {
 636         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);)
 637         return false;
 638       }
 639     } else {
 640       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());)
 641       return false;
 642     }
 643   }
 644 
 645   return true;
 646 }
 647 
 648 // Returns true if: 1) It's profitable to reduce the merge, and 2) The Phi is
 649 // only used in some certain code shapes. Check comments in
 650 // 'can_reduce_phi_inputs' and 'can_reduce_phi_users' for more
 651 // details.
 652 bool ConnectionGraph::can_reduce_phi(PhiNode* ophi) const {
 653   // If there was an error attempting to reduce allocation merges for this
 654   // method we might have disabled the compilation and be retrying with RAM
 655   // disabled.
 656   if (!_compile->do_reduce_allocation_merges() || ophi->region()->Opcode() != Op_Region) {
 657     return false;
 658   }
 659 
 660   const Type* phi_t = _igvn->type(ophi);
 661   if (phi_t == nullptr ||
 662       phi_t->make_ptr() == nullptr ||
 663       phi_t->make_ptr()->isa_aryptr() != nullptr) {
 664     return false;
 665   }
 666 
 667   if (!can_reduce_phi_check_inputs(ophi) || !can_reduce_check_users(ophi, /* nesting: */ 0)) {
 668     return false;
 669   }
 670 
 671   NOT_PRODUCT(if (TraceReduceAllocationMerges) { tty->print_cr("Can reduce Phi %d during invocation %d: ", ophi->_idx, _invocation); })
 672   return true;
 673 }
 674 
 675 // This method will return a CmpP/N that we need to use on the If controlling a
 676 // CastPP after it was split. This method is only called on bases that are
 677 // nullable therefore we always need a controlling if for the splitted CastPP.
 678 //
 679 // 'curr_ctrl' is the control of the CastPP that we want to split through phi.
 680 // If the CastPP currently doesn't have a control then the CmpP/N will be
 681 // against the null constant, otherwise it will be against the constant input of
 682 // the existing CmpP/N. It's guaranteed that there will be a CmpP/N in the later
 683 // case because we have constraints on it and because the CastPP has a control
 684 // input.
 685 Node* ConnectionGraph::specialize_cmp(Node* base, Node* curr_ctrl) {
 686   const Type* t = base->bottom_type();
 687   Node* con = nullptr;
 688 
 689   if (curr_ctrl == nullptr || curr_ctrl->is_Region()) {
 690     con = _igvn->zerocon(t->basic_type());
 691   } else {
 692     // can_reduce_check_users() verified graph: true/false -> if -> bool -> cmp
 693     assert(curr_ctrl->in(0)->Opcode() == Op_If, "unexpected node %s", curr_ctrl->in(0)->Name());
 694     Node* bol = curr_ctrl->in(0)->in(1);
 695     assert(bol->is_Bool(), "unexpected node %s", bol->Name());
 696     Node* curr_cmp = bol->in(1);
 697     assert(curr_cmp->Opcode() == Op_CmpP || curr_cmp->Opcode() == Op_CmpN, "unexpected node %s", curr_cmp->Name());
 698     con = curr_cmp->in(1)->is_Con() ? curr_cmp->in(1) : curr_cmp->in(2);
 699   }
 700 
 701   return CmpNode::make(base, con, t->basic_type());
 702 }
 703 
 704 // This method 'specializes' the CastPP passed as parameter to the base passed
 705 // as parameter. Note that the existing CastPP input is a Phi. "Specialize"
 706 // means that the CastPP now will be specific for a given base instead of a Phi.
 707 // An If-Then-Else-Region block is inserted to control the CastPP. The control
 708 // of the CastPP is a copy of the current one (if there is one) or a check
 709 // against null.
 710 //
 711 // Before:
 712 //
 713 //    C1     C2  ... Cn
 714 //     \      |      /
 715 //      \     |     /
 716 //       \    |    /
 717 //        \   |   /
 718 //         \  |  /
 719 //          \ | /
 720 //           \|/
 721 //          Region     B1      B2  ... Bn
 722 //            |          \      |      /
 723 //            |           \     |     /
 724 //            |            \    |    /
 725 //            |             \   |   /
 726 //            |              \  |  /
 727 //            |               \ | /
 728 //            ---------------> Phi
 729 //                              |
 730 //                      X       |
 731 //                      |       |
 732 //                      |       |
 733 //                      ------> CastPP
 734 //
 735 // After (only partial illustration; base = B2, current_control = C2):
 736 //
 737 //                      C2
 738 //                      |
 739 //                      If
 740 //                     / \
 741 //                    /   \
 742 //                   T     F
 743 //                  /\     /
 744 //                 /  \   /
 745 //                /    \ /
 746 //      C1    CastPP   Reg        Cn
 747 //       |              |          |
 748 //       |              |          |
 749 //       |              |          |
 750 //       -------------- | ----------
 751 //                    | | |
 752 //                    Region
 753 //
 754 Node* ConnectionGraph::specialize_castpp(Node* castpp, Node* base, Node* current_control) {
 755   Node* control_successor  = current_control->unique_ctrl_out();
 756   Node* cmp                = _igvn->transform(specialize_cmp(base, castpp->in(0)));
 757   Node* bol                = _igvn->transform(new BoolNode(cmp, BoolTest::ne));
 758   IfNode* if_ne            = _igvn->transform(new IfNode(current_control, bol, PROB_MIN, COUNT_UNKNOWN))->as_If();
 759   Node* not_eq_control     = _igvn->transform(new IfTrueNode(if_ne));
 760   Node* yes_eq_control     = _igvn->transform(new IfFalseNode(if_ne));
 761   Node* end_region         = _igvn->transform(new RegionNode(3));
 762 
 763   // Insert the new if-else-region block into the graph
 764   end_region->set_req(1, not_eq_control);
 765   end_region->set_req(2, yes_eq_control);
 766   control_successor->replace_edge(current_control, end_region, _igvn);
 767 
 768   _igvn->_worklist.push(current_control);
 769   _igvn->_worklist.push(control_successor);
 770 
 771   return _igvn->transform(ConstraintCastNode::make_cast_for_type(not_eq_control, base, _igvn->type(castpp), ConstraintCastNode::DependencyType::NonFloatingNonNarrowing, nullptr));
 772 }
 773 
 774 Node* ConnectionGraph::split_castpp_load_through_phi(Node* curr_addp, Node* curr_load, Node* region, GrowableArray<Node*>* bases_for_loads, GrowableArray<Node *>  &alloc_worklist) {
 775   const Type* load_type = _igvn->type(curr_load);
 776   Node* nsr_value = _igvn->zerocon(load_type->basic_type());
 777   Node* memory = curr_load->in(MemNode::Memory);
 778 
 779   // The data_phi merging the loads needs to be nullable if
 780   // we are loading pointers.
 781   if (load_type->make_ptr() != nullptr) {
 782     if (load_type->isa_narrowoop()) {
 783       load_type = load_type->meet(TypeNarrowOop::NULL_PTR);
 784     } else if (load_type->isa_ptr()) {
 785       load_type = load_type->meet(TypePtr::NULL_PTR);
 786     } else {
 787       assert(false, "Unexpected load ptr type.");
 788     }
 789   }
 790 
 791   Node* data_phi = PhiNode::make(region, nsr_value, load_type);
 792 
 793   for (int i = 1; i < bases_for_loads->length(); i++) {
 794     Node* base = bases_for_loads->at(i);
 795     Node* cmp_region = nullptr;
 796     if (base != nullptr) {
 797       if (base->is_CFG()) { // means that we added a CastPP as child of this CFG node
 798         cmp_region = base->unique_ctrl_out_or_null();
 799         assert(cmp_region != nullptr, "There should be.");
 800         base = base->find_out_with(Op_CastPP);
 801       }
 802 
 803       Node* addr = _igvn->transform(AddPNode::make_with_base(base, curr_addp->in(AddPNode::Offset)));
 804       Node* mem = (memory->is_Phi() && (memory->in(0) == region)) ? memory->in(i) : memory;
 805       Node* load = curr_load->clone();
 806       load->set_req(0, nullptr);
 807       load->set_req(1, mem);
 808       load->set_req(2, addr);
 809 
 810       if (cmp_region != nullptr) { // see comment on previous if
 811         Node* intermediate_phi = PhiNode::make(cmp_region, nsr_value, load_type);
 812         intermediate_phi->set_req(1, _igvn->transform(load));
 813         load = intermediate_phi;
 814       }
 815 
 816       data_phi->set_req(i, _igvn->transform(load));
 817     } else {
 818       // Just use the default, which is already in phi
 819     }
 820   }
 821 
 822   // Takes care of updating CG and split_unique_types worklists due
 823   // to cloned AddP->Load.
 824   updates_after_load_split(data_phi, curr_load, alloc_worklist);
 825 
 826   return _igvn->transform(data_phi);
 827 }
 828 
 829 // This method only reduces CastPP fields loads; SafePoints are handled
 830 // separately. The idea here is basically to clone the CastPP and place copies
 831 // on each input of the Phi, including non-scalar replaceable inputs.
 832 // Experimentation shows that the resulting IR graph is simpler that way than if
 833 // we just split the cast through scalar-replaceable inputs.
 834 //
 835 // The reduction process requires that CastPP's control be one of:
 836 //  1) no control,
 837 //  2) the same region as Ophi, or
 838 //  3) an IfTrue/IfFalse coming from an CmpP/N between Ophi and a constant.
 839 //
 840 // After splitting the CastPP we'll put it under an If-Then-Else-Region control
 841 // flow. If the CastPP originally had an IfTrue/False control input then we'll
 842 // use a similar CmpP/N to control the new If-Then-Else-Region. Otherwise, we'll
 843 // juse use a CmpP/N against the null constant.
 844 //
 845 // The If-Then-Else-Region isn't always needed. For instance, if input to
 846 // splitted cast was not nullable (or if it was the null constant) then we don't
 847 // need (shouldn't) use a CastPP at all.
 848 //
 849 // After the casts are splitted we'll split the AddP->Loads through the Phi and
 850 // connect them to the just split CastPPs.
 851 //
 852 // Before (CastPP control is same as Phi):
 853 //
 854 //          Region     Allocate   Null    Call
 855 //            |             \      |      /
 856 //            |              \     |     /
 857 //            |               \    |    /
 858 //            |                \   |   /
 859 //            |                 \  |  /
 860 //            |                  \ | /
 861 //            ------------------> Phi            # Oop Phi
 862 //            |                    |
 863 //            |                    |
 864 //            |                    |
 865 //            |                    |
 866 //            ----------------> CastPP
 867 //                                 |
 868 //                               AddP
 869 //                                 |
 870 //                               Load
 871 //
 872 // After (Very much simplified):
 873 //
 874 //                         Call  Null
 875 //                            \  /
 876 //                            CmpP
 877 //                             |
 878 //                           Bool#NE
 879 //                             |
 880 //                             If
 881 //                            / \
 882 //                           T   F
 883 //                          / \ /
 884 //                         /   R
 885 //                     CastPP  |
 886 //                       |     |
 887 //                     AddP    |
 888 //                       |     |
 889 //                     Load    |
 890 //                         \   |   0
 891 //            Allocate      \  |  /
 892 //                \          \ | /
 893 //               AddP         Phi
 894 //                  \         /
 895 //                 Load      /
 896 //                    \  0  /
 897 //                     \ | /
 898 //                      \|/
 899 //                      Phi        # "Field" Phi
 900 //
 901 void ConnectionGraph::reduce_phi_on_castpp_field_load(Node* curr_castpp, GrowableArray<Node*> &alloc_worklist) {
 902   Node* ophi = curr_castpp->in(1);
 903   assert(ophi->is_Phi(), "Expected this to be a Phi node.");
 904 
 905   // Identify which base should be used for AddP->Load later when spliting the
 906   // CastPP->Loads through ophi. Three kind of values may be stored in this
 907   // array, depending on the nullability status of the corresponding input in
 908   // ophi.
 909   //
 910   //  - nullptr:    Meaning that the base is actually the null constant and therefore
 911   //                we won't try to load from it.
 912   //
 913   //  - CFG Node:   Meaning that the base is a CastPP that was specialized for
 914   //                this input of Ophi. I.e., we added an If->Then->Else-Region
 915   //                that will 'activate' the CastPp only when the input is not Null.
 916   //
 917   //  - Other Node: Meaning that the base is not nullable and therefore we'll try
 918   //                to load directly from it.
 919   GrowableArray<Node*> bases_for_loads(ophi->req(), ophi->req(), nullptr);
 920 
 921   for (uint i = 1; i < ophi->req(); i++) {
 922     Node* base = ophi->in(i);
 923     const Type* base_t = _igvn->type(base);
 924 
 925     if (base_t->maybe_null()) {
 926       if (base->is_Con()) {
 927         // Nothing todo as bases_for_loads[i] is already null
 928       } else {
 929         Node* new_castpp = specialize_castpp(curr_castpp, base, ophi->in(0)->in(i));
 930         bases_for_loads.at_put(i, new_castpp->in(0)); // Use the ctrl of the new node just as a flag
 931       }
 932     } else {
 933       bases_for_loads.at_put(i, base);
 934     }
 935   }
 936 
 937   // Now let's split the CastPP->Loads through the Phi
 938   for (int i = curr_castpp->outcnt()-1; i >= 0;) {
 939     Node* use = curr_castpp->raw_out(i);
 940     if (use->is_AddP()) {
 941       for (int j = use->outcnt()-1; j >= 0;) {
 942         Node* use_use = use->raw_out(j);
 943         assert(use_use->is_Load(), "Expected this to be a Load node.");
 944 
 945         // We can't make an unconditional load from a nullable input. The
 946         // 'split_castpp_load_through_phi` method will add an
 947         // 'If-Then-Else-Region` around nullable bases and only load from them
 948         // when the input is not null.
 949         Node* phi = split_castpp_load_through_phi(use, use_use, ophi->in(0), &bases_for_loads, alloc_worklist);
 950         _igvn->replace_node(use_use, phi);
 951 
 952         --j;
 953         j = MIN2(j, (int)use->outcnt()-1);
 954       }
 955 
 956       _igvn->remove_dead_node(use, PhaseIterGVN::NodeOrigin::Graph);
 957     }
 958     --i;
 959     i = MIN2(i, (int)curr_castpp->outcnt()-1);
 960   }
 961 }
 962 
 963 // This method split a given CmpP/N through the Phi used in one of its inputs.
 964 // As a result we convert a comparison with a pointer to a comparison with an
 965 // integer.
 966 // The only requirement is that one of the inputs of the CmpP/N must be a Phi
 967 // while the other must be a constant.
 968 // The splitting process is basically just cloning the CmpP/N above the input
 969 // Phi.  However, some (most) of the cloned CmpP/Ns won't be requred because we
 970 // can prove at compile time the result of the comparison.
 971 //
 972 // Before:
 973 //
 974 //             in1    in2 ... inN
 975 //              \      |      /
 976 //               \     |     /
 977 //                \    |    /
 978 //                 \   |   /
 979 //                  \  |  /
 980 //                   \ | /
 981 //                    Phi
 982 //                     |   Other
 983 //                     |    /
 984 //                     |   /
 985 //                     |  /
 986 //                    CmpP/N
 987 //
 988 // After:
 989 //
 990 //        in1  Other   in2 Other  inN  Other
 991 //         |    |      |   |      |    |
 992 //         \    |      |   |      |    |
 993 //          \  /       |   /      |    /
 994 //          CmpP/N    CmpP/N     CmpP/N
 995 //          Bool      Bool       Bool
 996 //            \        |        /
 997 //             \       |       /
 998 //              \      |      /
 999 //               \     |     /
1000 //                \    |    /
1001 //                 \   |   /
1002 //                  \  |  /
1003 //                   \ | /
1004 //                    Phi
1005 //                     |
1006 //                     |   Zero
1007 //                     |    /
1008 //                     |   /
1009 //                     |  /
1010 //                     CmpI
1011 //
1012 //
1013 void ConnectionGraph::reduce_phi_on_cmp(Node* cmp) {
1014   Node* ophi = cmp->in(1)->is_Con() ? cmp->in(2) : cmp->in(1);
1015   assert(ophi->is_Phi(), "Expected this to be a Phi node.");
1016 
1017   Node* other = cmp->in(1)->is_Con() ? cmp->in(1) : cmp->in(2);
1018   Node* zero = _igvn->intcon(0);
1019   Node* one = _igvn->intcon(1);
1020   BoolTest::mask mask = cmp->unique_out()->as_Bool()->_test._test;
1021 
1022   // This Phi will merge the result of the Cmps split through the Phi
1023   Node* res_phi = PhiNode::make(ophi->in(0), zero, TypeInt::INT);
1024 
1025   for (uint i=1; i<ophi->req(); i++) {
1026     Node* ophi_input = ophi->in(i);
1027     Node* res_phi_input = nullptr;
1028 
1029     const TypeInt* tcmp = optimize_ptr_compare(ophi_input, other);
1030     if (tcmp->singleton()) {
1031       if ((mask == BoolTest::mask::eq && tcmp == TypeInt::CC_EQ) ||
1032           (mask == BoolTest::mask::ne && tcmp == TypeInt::CC_GT)) {
1033         res_phi_input = one;
1034       } else {
1035         res_phi_input = zero;
1036       }
1037     } else {
1038       Node* ncmp = _igvn->transform(cmp->clone());
1039       ncmp->set_req(1, ophi_input);
1040       ncmp->set_req(2, other);
1041       Node* bol = _igvn->transform(new BoolNode(ncmp, mask));
1042       res_phi_input = bol->as_Bool()->as_int_value(_igvn);
1043     }
1044 
1045     res_phi->set_req(i, res_phi_input);
1046   }
1047 
1048   // This CMP always compares whether the output of "res_phi" is TRUE as far as the "mask".
1049   Node* new_cmp = _igvn->transform(new CmpINode(_igvn->transform(res_phi), (mask == BoolTest::mask::eq) ? one : zero));
1050   _igvn->replace_node(cmp, new_cmp);
1051 }
1052 
1053 // Push the newly created AddP on alloc_worklist and patch
1054 // the connection graph. Note that the changes in the CG below
1055 // won't affect the ES of objects since the new nodes have the
1056 // same status as the old ones.
1057 void ConnectionGraph::updates_after_load_split(Node* data_phi, Node* previous_load, GrowableArray<Node *>  &alloc_worklist) {
1058   assert(data_phi != nullptr, "Output of split_through_phi is null.");
1059   assert(data_phi != previous_load, "Output of split_through_phi is same as input.");
1060   assert(data_phi->is_Phi(), "Output of split_through_phi isn't a Phi.");
1061 
1062   if (data_phi == nullptr || !data_phi->is_Phi()) {
1063     // Make this a retry?
1064     return ;
1065   }
1066 
1067   Node* previous_addp = previous_load->in(MemNode::Address);
1068   FieldNode* fn = ptnode_adr(previous_addp->_idx)->as_Field();
1069   for (uint i = 1; i < data_phi->req(); i++) {
1070     Node* new_load = data_phi->in(i);
1071 
1072     if (new_load->is_Phi()) {
1073       // new_load is currently the "intermediate_phi" from an specialized
1074       // CastPP.
1075       new_load = new_load->in(1);
1076     }
1077 
1078     // "new_load" might actually be a constant, parameter, etc.
1079     if (new_load->is_Load()) {
1080       Node* new_addp = new_load->in(MemNode::Address);
1081 
1082       // If new_load is a Load but not from an AddP, it means that the load is folded into another
1083       // load. And since this load is not from a field, we cannot create a unique type for it.
1084       // For example:
1085       //
1086       //   if (b) {
1087       //       Holder h1 = new Holder();
1088       //       Object o = ...;
1089       //       h.o = o.getClass();
1090       //   } else {
1091       //       Holder h2 = ...;
1092       //   }
1093       //   Holder h = Phi(h1, h2);
1094       //   Object r = h.o;
1095       //
1096       // Then, splitting r through the merge point results in:
1097       //
1098       //   if (b) {
1099       //       Holder h1 = new Holder();
1100       //       Object o = ...;
1101       //       h.o = o.getClass();
1102       //       Object o1 = h.o;
1103       //   } else {
1104       //       Holder h2 = ...;
1105       //       Object o2 = h2.o;
1106       //   }
1107       //   Object r = Phi(o1, o2);
1108       //
1109       // In this case, o1 is folded to o.getClass() which is a Load but not from an AddP, but from
1110       // an OopHandle that is loaded from the Klass of o.
1111       if (!new_addp->is_AddP()) {
1112         continue;
1113       }
1114       Node* base = get_addp_base(new_addp);
1115 
1116       // The base might not be something that we can create an unique
1117       // type for. If that's the case we are done with that input.
1118       PointsToNode* jobj_ptn = unique_java_object(base);
1119       if (jobj_ptn == nullptr || !jobj_ptn->scalar_replaceable()) {
1120         continue;
1121       }
1122 
1123       // Push to alloc_worklist since the base has an unique_type
1124       alloc_worklist.append_if_missing(new_addp);
1125 
1126       // Now let's add the node to the connection graph
1127       _nodes.at_grow(new_addp->_idx, nullptr);
1128       add_field(new_addp, fn->escape_state(), fn->offset());
1129       add_base(ptnode_adr(new_addp->_idx)->as_Field(), ptnode_adr(base->_idx));
1130 
1131       // If the load doesn't load an object then it won't be
1132       // part of the connection graph
1133       PointsToNode* curr_load_ptn = ptnode_adr(previous_load->_idx);
1134       if (curr_load_ptn != nullptr) {
1135         _nodes.at_grow(new_load->_idx, nullptr);
1136         add_local_var(new_load, curr_load_ptn->escape_state());
1137         add_edge(ptnode_adr(new_load->_idx), ptnode_adr(new_addp->_idx)->as_Field());
1138       }
1139     }
1140   }
1141 }
1142 
1143 void ConnectionGraph::reduce_phi_on_field_access(Node* previous_addp, GrowableArray<Node *>  &alloc_worklist) {
1144   // We'll pass this to 'split_through_phi' so that it'll do the split even
1145   // though the load doesn't have an unique instance type.
1146   bool ignore_missing_instance_id = true;
1147 
1148   // All AddPs are present in the connection graph
1149   FieldNode* fn = ptnode_adr(previous_addp->_idx)->as_Field();
1150 
1151   // Iterate over AddP looking for a Load
1152   for (int k = previous_addp->outcnt()-1; k >= 0;) {
1153     Node* previous_load = previous_addp->raw_out(k);
1154     if (previous_load->is_Load()) {
1155       Node* data_phi = previous_load->as_Load()->split_through_phi(_igvn, ignore_missing_instance_id);
1156 
1157       // Takes care of updating CG and split_unique_types worklists due to cloned
1158       // AddP->Load.
1159       updates_after_load_split(data_phi, previous_load, alloc_worklist);
1160 
1161       _igvn->replace_node(previous_load, data_phi);
1162     }
1163     --k;
1164     k = MIN2(k, (int)previous_addp->outcnt()-1);
1165   }
1166 
1167   // Remove the old AddP from the processing list because it's dead now
1168   assert(previous_addp->outcnt() == 0, "AddP should be dead now.");
1169   alloc_worklist.remove_if_existing(previous_addp);
1170 }
1171 
1172 // Create a 'selector' Phi based on the inputs of 'ophi'. If index 'i' of the
1173 // selector is:
1174 //    -> a '-1' constant, the i'th input of the original Phi is NSR.
1175 //    -> a 'x' constant >=0, the i'th input of of original Phi will be SR and
1176 //       the info about the scalarized object will be at index x of ObjectMergeValue::possible_objects
1177 PhiNode* ConnectionGraph::create_selector(PhiNode* ophi) const {
1178   Node* minus_one = _igvn->register_new_node_with_optimizer(ConINode::make(-1));
1179   Node* selector  = _igvn->register_new_node_with_optimizer(PhiNode::make(ophi->region(), minus_one, TypeInt::INT));
1180   uint number_of_sr_objects = 0;
1181   for (uint i = 1; i < ophi->req(); i++) {
1182     Node* base = ophi->in(i);
1183     JavaObjectNode* ptn = unique_java_object(base);
1184 
1185     if (ptn != nullptr && ptn->scalar_replaceable()) {
1186       Node* sr_obj_idx = _igvn->register_new_node_with_optimizer(ConINode::make(number_of_sr_objects));
1187       selector->set_req(i, sr_obj_idx);
1188       number_of_sr_objects++;
1189     }
1190   }
1191 
1192   return selector->as_Phi();
1193 }
1194 
1195 // Returns true if the AddP node 'n' has at least one base that is a reducible
1196 // merge. If the base is a CastPP/CheckCastPP then the input of the cast is
1197 // checked instead.
1198 bool ConnectionGraph::has_reducible_merge_base(AddPNode* n, Unique_Node_List &reducible_merges) {
1199   PointsToNode* ptn = ptnode_adr(n->_idx);
1200   if (ptn == nullptr || !ptn->is_Field() || ptn->as_Field()->base_count() < 2) {
1201     return false;
1202   }
1203 
1204   for (BaseIterator i(ptn->as_Field()); i.has_next(); i.next()) {
1205     Node* base = i.get()->ideal_node();
1206 
1207     if (reducible_merges.member(base)) {
1208       return true;
1209     }
1210 
1211     if (base->is_CastPP() || base->is_CheckCastPP()) {
1212       base = base->in(1);
1213       if (reducible_merges.member(base)) {
1214         return true;
1215       }
1216     }
1217   }
1218 
1219   return false;
1220 }
1221 
1222 // This method will call its helper method to reduce SafePoint nodes that use
1223 // 'ophi' or a casted version of 'ophi'. All SafePoint nodes using the same
1224 // "version" of Phi use the same debug information (regarding the Phi).
1225 // Therefore, I collect all safepoints and patch them all at once.
1226 //
1227 // The safepoints using the Phi node have to be processed before safepoints of
1228 // CastPP nodes. The reason is, when reducing a CastPP we add a reference (the
1229 // NSR merge pointer) to the input of the CastPP (i.e., the Phi) in the
1230 // safepoint. If we process CastPP's safepoints before Phi's safepoints the
1231 // algorithm that process Phi's safepoints will think that the added Phi
1232 // reference is a regular reference.
1233 bool ConnectionGraph::reduce_phi_on_safepoints(PhiNode* ophi) {
1234   PhiNode* selector = create_selector(ophi);
1235   Unique_Node_List safepoints;
1236   Unique_Node_List casts;
1237 
1238   // Just collect the users of the Phis for later processing
1239   // in the needed order.
1240   for (uint i = 0; i < ophi->outcnt(); i++) {
1241     Node* use = ophi->raw_out(i);
1242     if (use->is_SafePoint()) {
1243       safepoints.push(use);
1244     } else if (use->is_CastPP()) {
1245       casts.push(use);
1246     } else {
1247       assert(use->outcnt() == 0, "Only CastPP & SafePoint users should be left.");
1248     }
1249   }
1250 
1251   // Need to process safepoints using the Phi first
1252   if (!reduce_phi_on_safepoints_helper(ophi, nullptr, selector, safepoints)) {
1253     return false;
1254   }
1255 
1256   // Now process CastPP->safepoints
1257   for (uint i = 0; i < casts.size(); i++) {
1258     Node* cast = casts.at(i);
1259     Unique_Node_List cast_sfpts;
1260 
1261     for (DUIterator_Fast jmax, j = cast->fast_outs(jmax); j < jmax; j++) {
1262       Node* use_use = cast->fast_out(j);
1263       if (use_use->is_SafePoint()) {
1264         cast_sfpts.push(use_use);
1265       } else {
1266         assert(use_use->outcnt() == 0, "Only SafePoint users should be left.");
1267       }
1268     }
1269 
1270     if (!reduce_phi_on_safepoints_helper(ophi, cast, selector, cast_sfpts)) {
1271       return false;
1272     }
1273   }
1274 
1275   return true;
1276 }
1277 
1278 // This method will create a SafePointScalarMERGEnode for each SafePoint in
1279 // 'safepoints'. It then will iterate on the inputs of 'ophi' and create a
1280 // SafePointScalarObjectNode for each scalar replaceable input. Each
1281 // SafePointScalarMergeNode may describe multiple scalar replaced objects -
1282 // check detailed description in SafePointScalarMergeNode class header.
1283 bool ConnectionGraph::reduce_phi_on_safepoints_helper(Node* ophi, Node* cast, Node* selector, Unique_Node_List& safepoints) {
1284   PhaseMacroExpand mexp(*_igvn);
1285   Node* original_sfpt_parent =  cast != nullptr ? cast : ophi;
1286   const TypeOopPtr* merge_t = _igvn->type(original_sfpt_parent)->make_oopptr();
1287 
1288   Node* nsr_merge_pointer = ophi;
1289   if (cast != nullptr) {
1290     const Type* new_t = merge_t->meet(TypePtr::NULL_PTR);
1291     nsr_merge_pointer = _igvn->transform(ConstraintCastNode::make_cast_for_type(cast->in(0), cast->in(1), new_t, ConstraintCastNode::DependencyType::FloatingNarrowing, nullptr));
1292   }
1293 
1294   for (uint spi = 0; spi < safepoints.size(); spi++) {
1295     SafePointNode* sfpt = safepoints.at(spi)->as_SafePoint();
1296 
1297     SafePointNode::NodeEdgeTempStorage non_debug_edges_worklist(*_igvn);
1298 
1299     // All sfpt inputs are implicitly included into debug info during the scalarization process below.
1300     // Keep non-debug inputs separately, so they stay non-debug.
1301     sfpt->remove_non_debug_edges(non_debug_edges_worklist);
1302 
1303     JVMState* jvms  = sfpt->jvms();
1304     uint merge_idx  = (sfpt->req() - jvms->scloff());
1305     int debug_start = jvms->debug_start();
1306 
1307     SafePointScalarMergeNode* smerge = new SafePointScalarMergeNode(merge_t, merge_idx);
1308     smerge->init_req(0, _compile->root());
1309     _igvn->register_new_node_with_optimizer(smerge);
1310 
1311     assert(sfpt->jvms()->endoff() == sfpt->req(), "no extra edges past debug info allowed");
1312 
1313     // The next two inputs are:
1314     //  (1) A copy of the original pointer to NSR objects.
1315     //  (2) A selector, used to decide if we need to rematerialize an object
1316     //      or use the pointer to a NSR object.
1317     // See more details of these fields in the declaration of SafePointScalarMergeNode.
1318     // It is safe to include them into debug info straight away since create_scalarized_object_description()
1319     // will include all newly added inputs into debug info anyway.
1320     sfpt->add_req(nsr_merge_pointer);
1321     sfpt->add_req(selector);
1322     sfpt->jvms()->set_endoff(sfpt->req());
1323 
1324     for (uint i = 1; i < ophi->req(); i++) {
1325       Node* base = ophi->in(i);
1326       JavaObjectNode* ptn = unique_java_object(base);
1327 
1328       // If the base is not scalar replaceable we don't need to register information about
1329       // it at this time.
1330       if (ptn == nullptr || !ptn->scalar_replaceable()) {
1331         continue;
1332       }
1333 
1334       AllocateNode* alloc = ptn->ideal_node()->as_Allocate();
1335       Unique_Node_List value_worklist;
1336 #ifdef ASSERT
1337       const Type* res_type = alloc->result_cast()->bottom_type();
1338       if (res_type->is_inlinetypeptr() && !Compile::current()->has_circular_inline_type()) {
1339         PhiNode* phi = ophi->as_Phi();
1340         assert(!ophi->as_Phi()->can_push_inline_types_down(_igvn), "missed earlier scalarization opportunity");
1341       }
1342 #endif
1343       SafePointScalarObjectNode* sobj = mexp.create_scalarized_object_description(alloc, sfpt, &value_worklist);
1344       if (sobj == nullptr) {
1345         _compile->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1346         sfpt->restore_non_debug_edges(non_debug_edges_worklist);
1347         return false; // non-recoverable failure; recompile
1348       }
1349 
1350       // Now make a pass over the debug information replacing any references
1351       // to the allocated object with "sobj"
1352       Node* ccpp = alloc->result_cast();
1353       sfpt->replace_edges_in_range(ccpp, sobj, debug_start, jvms->debug_end(), _igvn);
1354       non_debug_edges_worklist.remove_edge_if_present(ccpp); // drop scalarized input from non-debug info
1355 
1356       // Register the scalarized object as a candidate for reallocation
1357       smerge->add_req(sobj);
1358 
1359       // Scalarize inline types that were added to the safepoint.
1360       // Don't allow linking a constant oop (if available) for flat array elements
1361       // because Deoptimization::reassign_flat_array_elements needs field values.
1362       const bool allow_oop = !merge_t->is_flat();
1363       for (uint j = 0; j < value_worklist.size(); ++j) {
1364         InlineTypeNode* vt = value_worklist.at(j)->as_InlineType();
1365         vt->make_scalar_in_safepoints(_igvn, allow_oop);
1366       }
1367     }
1368 
1369     // Replaces debug information references to "original_sfpt_parent" in "sfpt" with references to "smerge"
1370     sfpt->replace_edges_in_range(original_sfpt_parent, smerge, debug_start, jvms->debug_end(), _igvn);
1371     non_debug_edges_worklist.remove_edge_if_present(original_sfpt_parent); // drop scalarized input from non-debug info
1372 
1373     // The call to 'replace_edges_in_range' above might have removed the
1374     // reference to ophi that we need at _merge_pointer_idx. The line below make
1375     // sure the reference is maintained.
1376     sfpt->set_req(smerge->merge_pointer_idx(jvms), nsr_merge_pointer);
1377 
1378     sfpt->restore_non_debug_edges(non_debug_edges_worklist);
1379 
1380     _igvn->_worklist.push(sfpt);
1381   }
1382 
1383   return true;
1384 }
1385 
1386 void ConnectionGraph::reduce_phi(PhiNode* ophi, GrowableArray<Node*> &alloc_worklist) {
1387   bool delay = _igvn->delay_transform();
1388   _igvn->set_delay_transform(true);
1389   _igvn->hash_delete(ophi);
1390 
1391   // Copying all users first because some will be removed and others won't.
1392   // Ophi also may acquire some new users as part of Cast reduction.
1393   // CastPPs also need to be processed before CmpPs.
1394   Unique_Node_List castpps;
1395   Unique_Node_List others;
1396   for (DUIterator_Fast imax, i = ophi->fast_outs(imax); i < imax; i++) {
1397     Node* use = ophi->fast_out(i);
1398 
1399     if (use->is_CastPP()) {
1400       castpps.push(use);
1401     } else if (use->is_AddP() || use->is_Cmp()) {
1402       others.push(use);
1403     } else {
1404       // Safepoints to be processed later; other users aren't expected here
1405       assert(use->is_SafePoint(), "Unexpected user of reducible Phi %d -> %d:%s:%d", ophi->_idx, use->_idx, use->Name(), use->outcnt());
1406     }
1407   }
1408 
1409   _compile->print_method(PHASE_EA_BEFORE_PHI_REDUCTION, 5, ophi);
1410 
1411   // CastPPs need to be processed before Cmps because during the process of
1412   // splitting CastPPs we make reference to the inputs of the Cmp that is used
1413   // by the If controlling the CastPP.
1414   for (uint i = 0; i < castpps.size(); i++) {
1415     reduce_phi_on_castpp_field_load(castpps.at(i), alloc_worklist);
1416     _compile->print_method(PHASE_EA_AFTER_PHI_CASTPP_REDUCTION, 6, castpps.at(i));
1417   }
1418 
1419   for (uint i = 0; i < others.size(); i++) {
1420     Node* use = others.at(i);
1421 
1422     if (use->is_AddP()) {
1423       reduce_phi_on_field_access(use, alloc_worklist);
1424       _compile->print_method(PHASE_EA_AFTER_PHI_ADDP_REDUCTION, 6, use);
1425     } else if(use->is_Cmp()) {
1426       reduce_phi_on_cmp(use);
1427       _compile->print_method(PHASE_EA_AFTER_PHI_CMP_REDUCTION, 6, use);
1428     }
1429   }
1430 
1431   _igvn->set_delay_transform(delay);
1432 }
1433 
1434 void ConnectionGraph::reset_scalar_replaceable_entries(PhiNode* ophi) {
1435   Node* null_ptr            = _igvn->makecon(TypePtr::NULL_PTR);
1436   const TypeOopPtr* merge_t = _igvn->type(ophi)->make_oopptr();
1437   const Type* new_t         = merge_t->meet(TypePtr::NULL_PTR);
1438   Node* new_phi             = _igvn->register_new_node_with_optimizer(PhiNode::make(ophi->region(), null_ptr, new_t));
1439 
1440   for (uint i = 1; i < ophi->req(); i++) {
1441     Node* base          = ophi->in(i);
1442     JavaObjectNode* ptn = unique_java_object(base);
1443 
1444     if (ptn != nullptr && ptn->scalar_replaceable()) {
1445       new_phi->set_req(i, null_ptr);
1446     } else {
1447       new_phi->set_req(i, ophi->in(i));
1448     }
1449   }
1450 
1451   for (int i = ophi->outcnt()-1; i >= 0;) {
1452     Node* out = ophi->raw_out(i);
1453 
1454     if (out->is_ConstraintCast()) {
1455       const Type* out_t = _igvn->type(out)->make_ptr();
1456       const Type* out_new_t = out_t->meet(TypePtr::NULL_PTR);
1457       bool change = out_new_t != out_t;
1458 
1459       for (int j = out->outcnt()-1; change && j >= 0; --j) {
1460         Node* out2 = out->raw_out(j);
1461         if (!out2->is_SafePoint()) {
1462           change = false;
1463           break;
1464         }
1465       }
1466 
1467       if (change) {
1468         Node* new_cast = ConstraintCastNode::make_cast_for_type(out->in(0), out->in(1), out_new_t, ConstraintCastNode::DependencyType::NonFloatingNarrowing, nullptr);
1469         _igvn->replace_node(out, new_cast);
1470         _igvn->register_new_node_with_optimizer(new_cast);
1471       }
1472     }
1473 
1474     --i;
1475     i = MIN2(i, (int)ophi->outcnt()-1);
1476   }
1477 
1478   _igvn->replace_node(ophi, new_phi);
1479 }
1480 
1481 void ConnectionGraph::verify_ram_nodes(Compile* C, Node* root) {
1482   if (!C->do_reduce_allocation_merges()) return;
1483 
1484   Unique_Node_List ideal_nodes;
1485   ideal_nodes.map(C->live_nodes(), nullptr);  // preallocate space
1486   ideal_nodes.push(root);
1487 
1488   for (uint next = 0; next < ideal_nodes.size(); ++next) {
1489     Node* n = ideal_nodes.at(next);
1490 
1491     if (n->is_SafePointScalarMerge()) {
1492       SafePointScalarMergeNode* merge = n->as_SafePointScalarMerge();
1493 
1494       // Validate inputs of merge
1495       for (uint i = 1; i < merge->req(); i++) {
1496         if (merge->in(i) != nullptr && !merge->in(i)->is_top() && !merge->in(i)->is_SafePointScalarObject()) {
1497           assert(false, "SafePointScalarMerge inputs should be null/top or SafePointScalarObject.");
1498           C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1499         }
1500       }
1501 
1502       // Validate users of merge
1503       for (DUIterator_Fast imax, i = merge->fast_outs(imax); i < imax; i++) {
1504         Node* sfpt = merge->fast_out(i);
1505         if (sfpt->is_SafePoint()) {
1506           int merge_idx = merge->merge_pointer_idx(sfpt->as_SafePoint()->jvms());
1507 
1508           if (sfpt->in(merge_idx) != nullptr && sfpt->in(merge_idx)->is_SafePointScalarMerge()) {
1509             assert(false, "SafePointScalarMerge nodes can't be nested.");
1510             C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1511           }
1512         } else {
1513           assert(false, "Only safepoints can use SafePointScalarMerge nodes.");
1514           C->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
1515         }
1516       }
1517     }
1518 
1519     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1520       Node* m = n->fast_out(i);
1521       ideal_nodes.push(m);
1522     }
1523   }
1524 }
1525 
1526 // Returns true if there is an object in the scope of sfn that does not escape globally.
1527 bool ConnectionGraph::has_ea_local_in_scope(SafePointNode* sfn) {
1528   Compile* C = _compile;
1529   for (JVMState* jvms = sfn->jvms(); jvms != nullptr; jvms = jvms->caller()) {
1530     if (C->env()->should_retain_local_variables() || C->env()->jvmti_can_walk_any_space() ||
1531         DeoptimizeObjectsALot) {
1532       // Jvmti agents can access locals. Must provide info about local objects at runtime.
1533       int num_locs = jvms->loc_size();
1534       for (int idx = 0; idx < num_locs; idx++) {
1535         Node* l = sfn->local(jvms, idx);
1536         if (not_global_escape(l)) {
1537           return true;
1538         }
1539       }
1540     }
1541     if (C->env()->jvmti_can_get_owned_monitor_info() ||
1542         C->env()->jvmti_can_walk_any_space() || DeoptimizeObjectsALot) {
1543       // Jvmti agents can read monitors. Must provide info about locked objects at runtime.
1544       int num_mon = jvms->nof_monitors();
1545       for (int idx = 0; idx < num_mon; idx++) {
1546         Node* m = sfn->monitor_obj(jvms, idx);
1547         if (m != nullptr && not_global_escape(m)) {
1548           return true;
1549         }
1550       }
1551     }
1552   }
1553   return false;
1554 }
1555 
1556 // Returns true if at least one of the arguments to the call is an object
1557 // that does not escape globally.
1558 bool ConnectionGraph::has_arg_escape(CallJavaNode* call) {
1559   if (call->method() != nullptr) {
1560     uint max_idx = TypeFunc::Parms + call->method()->arg_size();
1561     for (uint idx = TypeFunc::Parms; idx < max_idx; idx++) {
1562       Node* p = call->in(idx);
1563       if (not_global_escape(p)) {
1564         return true;
1565       }
1566     }
1567   } else {
1568     const char* name = call->as_CallStaticJava()->_name;
1569     assert(name != nullptr, "no name");
1570     // no arg escapes through uncommon traps
1571     if (strcmp(name, "uncommon_trap") != 0) {
1572       // process_call_arguments() assumes that all arguments escape globally
1573       const TypeTuple* d = call->tf()->domain_sig();
1574       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1575         const Type* at = d->field_at(i);
1576         if (at->isa_oopptr() != nullptr) {
1577           return true;
1578         }
1579       }
1580     }
1581   }
1582   return false;
1583 }
1584 
1585 
1586 
1587 // Utility function for nodes that load an object
1588 void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
1589   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1590   // ThreadLocal has RawPtr type.
1591   const Type* t = _igvn->type(n);
1592   if (t->make_ptr() != nullptr) {
1593     Node* adr = n->in(MemNode::Address);
1594 #ifdef ASSERT
1595     if (!adr->is_AddP()) {
1596       assert(_igvn->type(adr)->isa_rawptr(), "sanity");
1597     } else {
1598       assert((ptnode_adr(adr->_idx) == nullptr ||
1599               ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
1600     }
1601 #endif
1602     add_local_var_and_edge(n, PointsToNode::NoEscape,
1603                            adr, delayed_worklist);
1604   }
1605 }
1606 
1607 void ConnectionGraph::add_proj(Node* n, Unique_Node_List* delayed_worklist) {
1608   if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() && n->in(0)->as_Call()->returns_pointer()) {
1609     add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), delayed_worklist);
1610   } else if (n->in(0)->is_LoadFlat()) {
1611     // Treat LoadFlat outputs similar to a call return value
1612     add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), delayed_worklist);
1613   } else if (n->as_Proj()->_con >= TypeFunc::Parms && n->in(0)->is_Call() && n->bottom_type()->isa_ptr()) {
1614     CallNode* call = n->in(0)->as_Call();
1615     assert(call->tf()->returns_inline_type_as_fields(), "");
1616     if (n->as_Proj()->_con == TypeFunc::Parms || !returns_an_argument(call)) {
1617       // either:
1618       // - not an argument returned
1619       // - the returned buffer for a returned scalarized argument
1620       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), delayed_worklist);
1621     } else {
1622       add_local_var(n, PointsToNode::NoEscape);
1623     }
1624   }
1625 }
1626 
1627 // Populate Connection Graph with PointsTo nodes and create simple
1628 // connection graph edges.
1629 void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
1630   assert(!_verify, "this method should not be called for verification");
1631   PhaseGVN* igvn = _igvn;
1632   uint n_idx = n->_idx;
1633   PointsToNode* n_ptn = ptnode_adr(n_idx);
1634   if (n_ptn != nullptr) {
1635     return; // No need to redefine PointsTo node during first iteration.
1636   }
1637   int opcode = n->Opcode();
1638   bool gc_handled = BarrierSet::barrier_set()->barrier_set_c2()->escape_add_to_con_graph(this, igvn, delayed_worklist, n, opcode);
1639   if (gc_handled) {
1640     return; // Ignore node if already handled by GC.
1641   }
1642 
1643   if (n->is_Call()) {
1644     // Arguments to allocation and locking don't escape.
1645     if (n->is_AbstractLock()) {
1646       // Put Lock and Unlock nodes on IGVN worklist to process them during
1647       // first IGVN optimization when escape information is still available.
1648       record_for_optimizer(n);
1649     } else if (n->is_Allocate()) {
1650       add_call_node(n->as_Call());
1651       record_for_optimizer(n);
1652     } else {
1653       if (n->is_CallStaticJava()) {
1654         const char* name = n->as_CallStaticJava()->_name;
1655         if (name != nullptr && strcmp(name, "uncommon_trap") == 0) {
1656           return; // Skip uncommon traps
1657         }
1658       }
1659       // Don't mark as processed since call's arguments have to be processed.
1660       delayed_worklist->push(n);
1661       // Check if a call returns an object.
1662       if ((n->as_Call()->returns_pointer() &&
1663            n->as_Call()->proj_out_or_null(TypeFunc::Parms) != nullptr) ||
1664           (n->is_CallStaticJava() &&
1665            n->as_CallStaticJava()->is_boxing_method())) {
1666         add_call_node(n->as_Call());
1667       } else if (n->as_Call()->tf()->returns_inline_type_as_fields()) {
1668         bool returns_oop = false;
1669         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax && !returns_oop; i++) {
1670           ProjNode* pn = n->fast_out(i)->as_Proj();
1671           if (pn->_con >= TypeFunc::Parms && pn->bottom_type()->isa_ptr()) {
1672             returns_oop = true;
1673           }
1674         }
1675         if (returns_oop) {
1676           add_call_node(n->as_Call());
1677         }
1678       }
1679     }
1680     return;
1681   }
1682   // Put this check here to process call arguments since some call nodes
1683   // point to phantom_obj.
1684   if (n_ptn == phantom_obj || n_ptn == null_obj) {
1685     return; // Skip predefined nodes.
1686   }
1687   switch (opcode) {
1688     case Op_AddP: {
1689       Node* base = get_addp_base(n);
1690       PointsToNode* ptn_base = ptnode_adr(base->_idx);
1691       // Field nodes are created for all field types. They are used in
1692       // adjust_scalar_replaceable_state() and split_unique_types().
1693       // Note, non-oop fields will have only base edges in Connection
1694       // Graph because such fields are not used for oop loads and stores.
1695       int offset = address_offset(n, igvn);
1696       add_field(n, PointsToNode::NoEscape, offset);
1697       if (ptn_base == nullptr) {
1698         delayed_worklist->push(n); // Process it later.
1699       } else {
1700         n_ptn = ptnode_adr(n_idx);
1701         add_base(n_ptn->as_Field(), ptn_base);
1702       }
1703       break;
1704     }
1705     case Op_CastX2P:
1706     case Op_CastI2N: {
1707       map_ideal_node(n, phantom_obj);
1708       break;
1709     }
1710     case Op_InlineType:
1711     case Op_CastPP:
1712     case Op_CheckCastPP:
1713     case Op_EncodeP:
1714     case Op_DecodeN:
1715     case Op_EncodePKlass:
1716     case Op_DecodeNKlass: {
1717       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), delayed_worklist);
1718       break;
1719     }
1720     case Op_CMoveP: {
1721       add_local_var(n, PointsToNode::NoEscape);
1722       // Do not add edges during first iteration because some could be
1723       // not defined yet.
1724       delayed_worklist->push(n);
1725       break;
1726     }
1727     case Op_ConP:
1728     case Op_ConN:
1729     case Op_ConNKlass: {
1730       // assume all oop constants globally escape except for null
1731       PointsToNode::EscapeState es;
1732       const Type* t = igvn->type(n);
1733       if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
1734         es = PointsToNode::NoEscape;
1735       } else {
1736         es = PointsToNode::GlobalEscape;
1737       }
1738       PointsToNode* ptn_con = add_java_object(n, es);
1739       set_not_scalar_replaceable(ptn_con NOT_PRODUCT(COMMA "Constant pointer"));
1740       break;
1741     }
1742     case Op_CreateEx: {
1743       // assume that all exception objects globally escape
1744       map_ideal_node(n, phantom_obj);
1745       break;
1746     }
1747     case Op_LoadKlass:
1748     case Op_LoadNKlass: {
1749       // Unknown class is loaded
1750       map_ideal_node(n, phantom_obj);
1751       break;
1752     }
1753     case Op_LoadP:
1754     case Op_LoadN: {
1755       add_objload_to_connection_graph(n, delayed_worklist);
1756       break;
1757     }
1758     case Op_Parm: {
1759       map_ideal_node(n, phantom_obj);
1760       break;
1761     }
1762     case Op_PartialSubtypeCheck: {
1763       // Produces Null or notNull and is used in only in CmpP so
1764       // phantom_obj could be used.
1765       map_ideal_node(n, phantom_obj); // Result is unknown
1766       break;
1767     }
1768     case Op_Phi: {
1769       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1770       // ThreadLocal has RawPtr type.
1771       const Type* t = n->as_Phi()->type();
1772       if (t->make_ptr() != nullptr) {
1773         add_local_var(n, PointsToNode::NoEscape);
1774         // Do not add edges during first iteration because some could be
1775         // not defined yet.
1776         delayed_worklist->push(n);
1777       }
1778       break;
1779     }
1780     case Op_LoadFlat:
1781       // Treat LoadFlat similar to an unknown call that receives nothing and produces its results
1782       map_ideal_node(n, phantom_obj);
1783       break;
1784     case Op_StoreFlat:
1785       // Treat StoreFlat similar to a call that escapes the stored flattened fields
1786       delayed_worklist->push(n);
1787       break;
1788     case Op_Proj: {
1789       // we are only interested in the oop result projection from a call
1790       add_proj(n, delayed_worklist);



1791       break;
1792     }
1793     case Op_Rethrow: // Exception object escapes
1794     case Op_Return: {
1795       if (n->req() > TypeFunc::Parms &&
1796           igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
1797         // Treat Return value as LocalVar with GlobalEscape escape state.
1798         add_local_var_and_edge(n, PointsToNode::GlobalEscape, n->in(TypeFunc::Parms), delayed_worklist);
1799       }
1800       break;
1801     }
1802     case Op_CompareAndExchangeP:
1803     case Op_CompareAndExchangeN:
1804     case Op_GetAndSetP:
1805     case Op_GetAndSetN: {
1806       add_objload_to_connection_graph(n, delayed_worklist);
1807       // fall-through
1808     }
1809     case Op_StoreP:
1810     case Op_StoreN:
1811     case Op_StoreNKlass:
1812     case Op_WeakCompareAndSwapP:
1813     case Op_WeakCompareAndSwapN:
1814     case Op_CompareAndSwapP:
1815     case Op_CompareAndSwapN: {
1816       add_to_congraph_unsafe_access(n, opcode, delayed_worklist);
1817       break;
1818     }
1819     case Op_AryEq:
1820     case Op_CountPositives:
1821     case Op_StrComp:
1822     case Op_StrEquals:
1823     case Op_StrIndexOf:
1824     case Op_StrIndexOfChar:
1825     case Op_StrInflatedCopy:
1826     case Op_StrCompressedCopy:
1827     case Op_VectorizedHashCode:
1828     case Op_EncodeISOArray: {
1829       add_local_var(n, PointsToNode::ArgEscape);
1830       delayed_worklist->push(n); // Process it later.
1831       break;
1832     }
1833     case Op_ThreadLocal: {
1834       PointsToNode* ptn_thr = add_java_object(n, PointsToNode::ArgEscape);
1835       set_not_scalar_replaceable(ptn_thr NOT_PRODUCT(COMMA "Constant pointer"));
1836       break;
1837     }
1838     case Op_Blackhole: {
1839       // All blackhole pointer arguments are globally escaping.
1840       // Only do this if there is at least one pointer argument.
1841       // Do not add edges during first iteration because some could be
1842       // not defined yet, defer to final step.
1843       for (uint i = 0; i < n->req(); i++) {
1844         Node* in = n->in(i);
1845         if (in != nullptr) {
1846           const Type* at = _igvn->type(in);
1847           if (!at->isa_ptr()) continue;
1848 
1849           add_local_var(n, PointsToNode::GlobalEscape);
1850           delayed_worklist->push(n);
1851           break;
1852         }
1853       }
1854       break;
1855     }
1856     default:
1857       ; // Do nothing for nodes not related to EA.
1858   }
1859   return;
1860 }
1861 
1862 // Add final simple edges to graph.
1863 void ConnectionGraph::add_final_edges(Node *n) {
1864   PointsToNode* n_ptn = ptnode_adr(n->_idx);
1865 #ifdef ASSERT
1866   if (_verify && n_ptn->is_JavaObject())
1867     return; // This method does not change graph for JavaObject.
1868 #endif
1869 
1870   if (n->is_Call()) {
1871     process_call_arguments(n->as_Call());
1872     return;
1873   }
1874   assert(n->is_Store() || n->is_LoadStore() || n->is_StoreFlat() ||
1875          ((n_ptn != nullptr) && (n_ptn->ideal_node() != nullptr)),
1876          "node should be registered already");
1877   int opcode = n->Opcode();
1878   bool gc_handled = BarrierSet::barrier_set()->barrier_set_c2()->escape_add_final_edges(this, _igvn, n, opcode);
1879   if (gc_handled) {
1880     return; // Ignore node if already handled by GC.
1881   }
1882   switch (opcode) {
1883     case Op_AddP: {
1884       Node* base = get_addp_base(n);
1885       PointsToNode* ptn_base = ptnode_adr(base->_idx);
1886       assert(ptn_base != nullptr, "field's base should be registered");
1887       add_base(n_ptn->as_Field(), ptn_base);
1888       break;
1889     }
1890     case Op_InlineType:
1891     case Op_CastPP:
1892     case Op_CheckCastPP:
1893     case Op_EncodeP:
1894     case Op_DecodeN:
1895     case Op_EncodePKlass:
1896     case Op_DecodeNKlass: {
1897       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(1), nullptr);
1898       break;
1899     }
1900     case Op_CMoveP: {
1901       for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
1902         Node* in = n->in(i);
1903         if (in == nullptr) {
1904           continue;  // ignore null
1905         }
1906         Node* uncast_in = in->uncast();
1907         if (uncast_in->is_top() || uncast_in == n) {
1908           continue;  // ignore top or inputs which go back this node
1909         }
1910         PointsToNode* ptn = ptnode_adr(in->_idx);
1911         assert(ptn != nullptr, "node should be registered");
1912         add_edge(n_ptn, ptn);
1913       }
1914       break;
1915     }
1916     case Op_LoadP:
1917     case Op_LoadN: {
1918       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1919       // ThreadLocal has RawPtr type.
1920       assert(_igvn->type(n)->make_ptr() != nullptr, "Unexpected node type");
1921       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(MemNode::Address), nullptr);
1922       break;
1923     }
1924     case Op_Phi: {
1925       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
1926       // ThreadLocal has RawPtr type.
1927       assert(n->as_Phi()->type()->make_ptr() != nullptr, "Unexpected node type");
1928       for (uint i = 1; i < n->req(); i++) {
1929         Node* in = n->in(i);
1930         if (in == nullptr) {
1931           continue;  // ignore null
1932         }
1933         Node* uncast_in = in->uncast();
1934         if (uncast_in->is_top() || uncast_in == n) {
1935           continue;  // ignore top or inputs which go back this node
1936         }
1937         PointsToNode* ptn = ptnode_adr(in->_idx);
1938         assert(ptn != nullptr, "node should be registered");
1939         add_edge(n_ptn, ptn);
1940       }
1941       break;
1942     }
1943     case Op_StoreFlat: {
1944       // StoreFlat globally escapes its stored flattened fields
1945       InlineTypeNode* value = n->as_StoreFlat()->value();
1946       ciInlineKlass* vk = _igvn->type(value)->inline_klass();
1947       for (int i = 0; i < vk->nof_nonstatic_fields(); i++) {
1948         ciField* field = vk->nonstatic_field_at(i);
1949         if (field->type()->is_primitive_type()) {
1950           continue;
1951         }
1952 
1953         Node* field_value = value->field_value_by_offset(field->offset_in_bytes(), true);
1954         PointsToNode* field_value_ptn = ptnode_adr(field_value->_idx);
1955         set_escape_state(field_value_ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA "store into a flat field"));
1956       }
1957       break;
1958     }
1959     case Op_Proj: {
1960       add_proj(n, nullptr);



1961       break;
1962     }
1963     case Op_Rethrow: // Exception object escapes
1964     case Op_Return: {
1965       assert(n->req() > TypeFunc::Parms && _igvn->type(n->in(TypeFunc::Parms))->isa_oopptr(),
1966              "Unexpected node type");
1967       // Treat Return value as LocalVar with GlobalEscape escape state.
1968       add_local_var_and_edge(n, PointsToNode::GlobalEscape, n->in(TypeFunc::Parms), nullptr);
1969       break;
1970     }
1971     case Op_CompareAndExchangeP:
1972     case Op_CompareAndExchangeN:
1973     case Op_GetAndSetP:
1974     case Op_GetAndSetN:{
1975       assert(_igvn->type(n)->make_ptr() != nullptr, "Unexpected node type");
1976       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(MemNode::Address), nullptr);
1977       // fall-through
1978     }
1979     case Op_CompareAndSwapP:
1980     case Op_CompareAndSwapN:
1981     case Op_WeakCompareAndSwapP:
1982     case Op_WeakCompareAndSwapN:
1983     case Op_StoreP:
1984     case Op_StoreN:
1985     case Op_StoreNKlass:{
1986       add_final_edges_unsafe_access(n, opcode);
1987       break;
1988     }
1989     case Op_VectorizedHashCode:
1990     case Op_AryEq:
1991     case Op_CountPositives:
1992     case Op_StrComp:
1993     case Op_StrEquals:
1994     case Op_StrIndexOf:
1995     case Op_StrIndexOfChar:
1996     case Op_StrInflatedCopy:
1997     case Op_StrCompressedCopy:
1998     case Op_EncodeISOArray: {
1999       // char[]/byte[] arrays passed to string intrinsic do not escape but
2000       // they are not scalar replaceable. Adjust escape state for them.
2001       // Start from in(2) edge since in(1) is memory edge.
2002       for (uint i = 2; i < n->req(); i++) {
2003         Node* adr = n->in(i);
2004         const Type* at = _igvn->type(adr);
2005         if (!adr->is_top() && at->isa_ptr()) {
2006           assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
2007                  at->isa_ptr() != nullptr, "expecting a pointer");
2008           if (adr->is_AddP()) {
2009             adr = get_addp_base(adr);
2010           }
2011           PointsToNode* ptn = ptnode_adr(adr->_idx);
2012           assert(ptn != nullptr, "node should be registered");
2013           add_edge(n_ptn, ptn);
2014         }
2015       }
2016       break;
2017     }
2018     case Op_Blackhole: {
2019       // All blackhole pointer arguments are globally escaping.
2020       for (uint i = 0; i < n->req(); i++) {
2021         Node* in = n->in(i);
2022         if (in != nullptr) {
2023           const Type* at = _igvn->type(in);
2024           if (!at->isa_ptr()) continue;
2025 
2026           if (in->is_AddP()) {
2027             in = get_addp_base(in);
2028           }
2029 
2030           PointsToNode* ptn = ptnode_adr(in->_idx);
2031           assert(ptn != nullptr, "should be defined already");
2032           set_escape_state(ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA "blackhole"));
2033           add_edge(n_ptn, ptn);
2034         }
2035       }
2036       break;
2037     }
2038     default: {
2039       // This method should be called only for EA specific nodes which may
2040       // miss some edges when they were created.
2041 #ifdef ASSERT
2042       n->dump(1);
2043 #endif
2044       guarantee(false, "unknown node");
2045     }
2046   }
2047   return;
2048 }
2049 
2050 void ConnectionGraph::add_to_congraph_unsafe_access(Node* n, uint opcode, Unique_Node_List* delayed_worklist) {
2051   Node* adr = n->in(MemNode::Address);
2052   const Type* adr_type = _igvn->type(adr);
2053   adr_type = adr_type->make_ptr();
2054   if (adr_type == nullptr) {
2055     return; // skip dead nodes
2056   }
2057   if (adr_type->isa_oopptr()
2058       || ((opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass)
2059           && adr_type == TypeRawPtr::NOTNULL
2060           && is_captured_store_address(adr))) {
2061     delayed_worklist->push(n); // Process it later.
2062 #ifdef ASSERT
2063     assert (adr->is_AddP(), "expecting an AddP");
2064     if (adr_type == TypeRawPtr::NOTNULL) {
2065       // Verify a raw address for a store captured by Initialize node.
2066       int offs = (int) _igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
2067       assert(offs != Type::OffsetBot, "offset must be a constant");
2068     }
2069 #endif
2070   } else {
2071     // Ignore copy the displaced header to the BoxNode (OSR compilation).
2072     if (adr->is_BoxLock()) {
2073       return;
2074     }
2075     // Stored value escapes in unsafe access.
2076     if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
2077       delayed_worklist->push(n); // Process unsafe access later.
2078       return;
2079     }
2080 #ifdef ASSERT
2081     n->dump(1);
2082     assert(false, "not unsafe");
2083 #endif
2084   }
2085 }
2086 
2087 bool ConnectionGraph::add_final_edges_unsafe_access(Node* n, uint opcode) {
2088   Node* adr = n->in(MemNode::Address);
2089   const Type *adr_type = _igvn->type(adr);
2090   adr_type = adr_type->make_ptr();
2091 #ifdef ASSERT
2092   if (adr_type == nullptr) {
2093     n->dump(1);
2094     assert(adr_type != nullptr, "dead node should not be on list");
2095     return true;
2096   }
2097 #endif
2098 
2099   if (adr_type->isa_oopptr()
2100       || ((opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass)
2101            && adr_type == TypeRawPtr::NOTNULL
2102            && is_captured_store_address(adr))) {
2103     // Point Address to Value
2104     PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
2105     assert(adr_ptn != nullptr &&
2106            adr_ptn->as_Field()->is_oop(), "node should be registered");
2107     Node* val = n->in(MemNode::ValueIn);
2108     PointsToNode* ptn = ptnode_adr(val->_idx);
2109     assert(ptn != nullptr, "node should be registered");
2110     add_edge(adr_ptn, ptn);
2111     return true;
2112   } else if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
2113     // Stored value escapes in unsafe access.
2114     Node* val = n->in(MemNode::ValueIn);
2115     PointsToNode* ptn = ptnode_adr(val->_idx);
2116     assert(ptn != nullptr, "node should be registered");
2117     set_escape_state(ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA "stored at raw address"));
2118     // Add edge to object for unsafe access with offset.
2119     PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
2120     assert(adr_ptn != nullptr, "node should be registered");
2121     if (adr_ptn->is_Field()) {
2122       assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
2123       add_edge(adr_ptn, ptn);
2124     }
2125     return true;
2126   }
2127 #ifdef ASSERT
2128   n->dump(1);
2129   assert(false, "not unsafe");
2130 #endif
2131   return false;
2132 }
2133 
2134 // Iterate over the domains for the scalarized and non scalarized calling conventions: Only move to the next element
2135 // in the non scalarized calling convention once all elements of the scalarized calling convention for that parameter
2136 // have been iterated over. So (ignoring hidden arguments such as the null marker) iterating over:
2137 // value class MyValue {
2138 //   int f1;
2139 //   float f2;
2140 // }
2141 // void m(Object o, MyValue v, int i)
2142 // produces the pairs:
2143 // (Object, Object), (Myvalue, int), (MyValue, float), (int, int)
2144 class DomainIterator : public StackObj {
2145 private:
2146   const TypeTuple* _domain;
2147   const TypeTuple* _domain_cc;
2148   const GrowableArray<SigEntry>* _sig_cc;
2149 
2150   uint _i_domain;
2151   uint _i_domain_cc;
2152   int _i_sig_cc;
2153   uint _depth;
2154   uint _first_field_pos;
2155   const bool _is_static;
2156 
2157   void next_helper() {
2158     if (_sig_cc == nullptr) {
2159       return;
2160     }
2161     BasicType prev_bt = _i_sig_cc > 0 ? _sig_cc->at(_i_sig_cc-1)._bt : T_ILLEGAL;
2162     BasicType prev_prev_bt = _i_sig_cc > 1 ? _sig_cc->at(_i_sig_cc-2)._bt : T_ILLEGAL;
2163     while (_i_sig_cc < _sig_cc->length()) {
2164       BasicType bt = _sig_cc->at(_i_sig_cc)._bt;
2165       assert(bt != T_VOID || _sig_cc->at(_i_sig_cc-1)._bt == prev_bt, "incorrect prev bt");
2166       if (bt == T_METADATA) {
2167         if (_depth == 0) {
2168           _first_field_pos = _i_domain_cc;
2169         }
2170         _depth++;
2171       } else if (bt == T_VOID && (prev_bt != T_LONG && prev_bt != T_DOUBLE)) {
2172         _depth--;
2173         if (_depth == 0) {
2174           _i_domain++;
2175         }
2176       } else if (bt == T_OBJECT && prev_bt == T_METADATA && (_is_static || _i_domain > 0) && _sig_cc->at(_i_sig_cc)._offset == 0) {
2177         assert(_sig_cc->at(_i_sig_cc)._vt_oop, "buffer expected right after T_METADATA");
2178         assert(_depth == 1, "only root value has buffer");
2179         _i_domain_cc++;
2180         _first_field_pos = _i_domain_cc;
2181       } else if (bt == T_BOOLEAN && prev_prev_bt == T_METADATA && (_is_static || _i_domain > 0) && _sig_cc->at(_i_sig_cc)._offset == -1) {
2182         assert(_sig_cc->at(_i_sig_cc)._null_marker, "null marker expected right after T_METADATA");
2183         assert(_depth == 1, "only root value null marker");
2184         _i_domain_cc++;
2185         _first_field_pos = _i_domain_cc;
2186       } else {
2187         return;
2188       }
2189       prev_prev_bt = prev_bt;
2190       prev_bt = bt;
2191       _i_sig_cc++;
2192     }
2193   }
2194 
2195 public:
2196 
2197   DomainIterator(CallJavaNode* call) :
2198     _domain(call->tf()->domain_sig()),
2199     _domain_cc(call->tf()->domain_cc()),
2200     _sig_cc(call->method()->get_sig_cc()),
2201     _i_domain(TypeFunc::Parms),
2202     _i_domain_cc(TypeFunc::Parms),
2203     _i_sig_cc(0),
2204     _depth(0),
2205     _first_field_pos(0),
2206     _is_static(call->method()->is_static()) {
2207     next_helper();
2208   }
2209 
2210   bool has_next() const {
2211     assert(_sig_cc == nullptr || (_i_sig_cc < _sig_cc->length()) == (_i_domain < _domain->cnt()), "should reach end in sync");
2212     assert((_i_domain < _domain->cnt()) == (_i_domain_cc < _domain_cc->cnt()), "should reach end in sync");
2213     return _i_domain < _domain->cnt();
2214   }
2215 
2216   void next() {
2217     assert(_depth != 0 || _domain->field_at(_i_domain) == _domain_cc->field_at(_i_domain_cc), "should produce same non scalarized elements");
2218     _i_sig_cc++;
2219     if (_depth == 0) {
2220       _i_domain++;
2221     }
2222     _i_domain_cc++;
2223     next_helper();
2224   }
2225 
2226   uint i_domain() const {
2227     return _i_domain;
2228   }
2229 
2230   uint i_domain_cc() const {
2231     return _i_domain_cc;
2232   }
2233 
2234   const Type* current_domain() const {
2235     return _domain->field_at(_i_domain);
2236   }
2237 
2238   const Type* current_domain_cc() const {
2239     return _domain_cc->field_at(_i_domain_cc);
2240   }
2241 
2242   uint first_field_pos() const {
2243     assert(_first_field_pos >= TypeFunc::Parms, "not yet updated?");
2244     return _first_field_pos;
2245   }
2246 };
2247 
2248 // Determine whether any arguments are returned.
2249 bool ConnectionGraph::returns_an_argument(CallNode* call) {
2250   ciMethod* meth = call->as_CallJava()->method();
2251   BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
2252   if (call_analyzer == nullptr) {
2253     return false;
2254   }
2255 
2256   const TypeTuple* d = call->tf()->domain_sig();
2257   bool ret_arg = false;
2258   for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2259     if (d->field_at(i)->isa_ptr() != nullptr &&
2260         call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
2261       if (meth->is_scalarized_arg(i - TypeFunc::Parms) && !compatible_return(call->as_CallJava(), i)) {
2262         return false;
2263       }
2264       if (call->tf()->returns_inline_type_as_fields() != meth->is_scalarized_arg(i - TypeFunc::Parms)) {
2265         return false;
2266       }
2267       ret_arg = true;
2268     }
2269   }
2270   return ret_arg;
2271 }
2272 
2273 void ConnectionGraph::add_call_node(CallNode* call) {
2274   assert(call->returns_pointer() || call->tf()->returns_inline_type_as_fields(), "only for call which returns pointer");
2275   uint call_idx = call->_idx;
2276   if (call->is_Allocate()) {
2277     Node* k = call->in(AllocateNode::KlassNode);
2278     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
2279     assert(kt != nullptr, "TypeKlassPtr  required.");
2280     PointsToNode::EscapeState es = PointsToNode::NoEscape;
2281     bool scalar_replaceable = true;
2282     NOT_PRODUCT(const char* nsr_reason = "");
2283     if (call->is_AllocateArray()) {
2284       if (!kt->isa_aryklassptr()) { // StressReflectiveCode
2285         es = PointsToNode::GlobalEscape;
2286       } else {
2287         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
2288         if (length < 0) {
2289           // Not scalar replaceable if the length is not constant.
2290           scalar_replaceable = false;
2291           NOT_PRODUCT(nsr_reason = "has a non-constant length");
2292         } else if (length > EliminateAllocationArraySizeLimit) {
2293           // Not scalar replaceable if the length is too big.
2294           scalar_replaceable = false;
2295           NOT_PRODUCT(nsr_reason = "has a length that is too big");
2296         }
2297       }
2298     } else {  // Allocate instance
2299       if (!kt->isa_instklassptr()) { // StressReflectiveCode
2300         es = PointsToNode::GlobalEscape;
2301       } else {
2302         const TypeInstKlassPtr* ikt = kt->is_instklassptr();
2303         ciInstanceKlass* ik = ikt->klass_is_exact() ? ikt->exact_klass()->as_instance_klass() : ikt->instance_klass();
2304         if (ik->is_subclass_of(_compile->env()->Thread_klass()) ||
2305             ik->is_subclass_of(_compile->env()->Reference_klass()) ||
2306             !ik->can_be_instantiated() ||
2307             ik->has_finalizer()) {
2308           es = PointsToNode::GlobalEscape;
2309         } else {
2310           int nfields = ik->as_instance_klass()->nof_nonstatic_fields();
2311           if (nfields > EliminateAllocationFieldsLimit) {
2312             // Not scalar replaceable if there are too many fields.
2313             scalar_replaceable = false;
2314             NOT_PRODUCT(nsr_reason = "has too many fields");
2315           }
2316         }
2317       }
2318     }
2319     add_java_object(call, es);
2320     PointsToNode* ptn = ptnode_adr(call_idx);
2321     if (!scalar_replaceable && ptn->scalar_replaceable()) {
2322       set_not_scalar_replaceable(ptn NOT_PRODUCT(COMMA nsr_reason));
2323     }
2324   } else if (call->is_CallStaticJava()) {
2325     // Call nodes could be different types:
2326     //
2327     // 1. CallDynamicJavaNode (what happened during call is unknown):
2328     //
2329     //    - mapped to GlobalEscape JavaObject node if oop is returned;
2330     //
2331     //    - all oop arguments are escaping globally;
2332     //
2333     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
2334     //
2335     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
2336     //
2337     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
2338     //    - mapped to NoEscape JavaObject node if non-escaping object allocated
2339     //      during call is returned;
2340     //    - mapped to ArgEscape LocalVar node pointed to object arguments
2341     //      which are returned and does not escape during call;
2342     //
2343     //    - oop arguments escaping status is defined by bytecode analysis;
2344     //
2345     // For a static call, we know exactly what method is being called.
2346     // Use bytecode estimator to record whether the call's return value escapes.
2347     ciMethod* meth = call->as_CallJava()->method();
2348     if (meth == nullptr) {
2349       const char* name = call->as_CallStaticJava()->_name;
2350       assert(call->as_CallStaticJava()->is_call_to_multianewarray_stub() ||
2351              strncmp(name, "load_unknown_inline", 19) == 0 ||
2352              strncmp(name, "store_inline_type_fields_to_buf", 31) == 0, "TODO: add failed case check");
2353       // Returns a newly allocated non-escaped object.
2354       add_java_object(call, PointsToNode::NoEscape);
2355       set_not_scalar_replaceable(ptnode_adr(call_idx) NOT_PRODUCT(COMMA "is result of multinewarray"));
2356     } else if (meth->is_boxing_method()) {
2357       // Returns boxing object
2358       PointsToNode::EscapeState es;
2359       vmIntrinsics::ID intr = meth->intrinsic_id();
2360       if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
2361         // It does not escape if object is always allocated.
2362         es = PointsToNode::NoEscape;
2363       } else {
2364         // It escapes globally if object could be loaded from cache.
2365         es = PointsToNode::GlobalEscape;
2366       }
2367       add_java_object(call, es);
2368       if (es == PointsToNode::GlobalEscape) {
2369         set_not_scalar_replaceable(ptnode_adr(call->_idx) NOT_PRODUCT(COMMA "object can be loaded from boxing cache"));
2370       }
2371     } else {
2372       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
2373       call_analyzer->copy_dependencies(_compile->dependencies());
2374       if (call_analyzer->is_return_allocated()) {
2375         // Returns a newly allocated non-escaped object, simply
2376         // update dependency information.
2377         // Mark it as NoEscape so that objects referenced by
2378         // it's fields will be marked as NoEscape at least.
2379         add_java_object(call, PointsToNode::NoEscape);
2380         set_not_scalar_replaceable(ptnode_adr(call_idx) NOT_PRODUCT(COMMA "is result of call"));
2381       } else {
2382         // For non scalarized argument/return: add_proj() adds an edge between the return projection and the call,
2383         // process_call_arguments() adds an edge between the call and the argument
2384         // For scalarized argument/return: process_call_arguments() adds an edge between a call projection for a field
2385         // and the argument input to the call for that field. An edge is added between the projection for the returned
2386         // buffer and the call.
2387         if (returns_an_argument(call) && !call->tf()->returns_inline_type_as_fields()) {
2388           // returns non scalarized argument




2389           add_local_var(call, PointsToNode::ArgEscape);
2390         } else {
2391           // Returns unknown object or scalarized argument being returned
2392           map_ideal_node(call, phantom_obj);
2393         }
2394       }
2395     }
2396   } else {
2397     // An other type of call, assume the worst case:
2398     // returned value is unknown and globally escapes.
2399     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
2400     map_ideal_node(call, phantom_obj);
2401   }
2402 }
2403 
2404 // Check that the return type is compatible with the type of the argument being returned i.e. that there's no cast that
2405 // fails in the method
2406 bool ConnectionGraph::compatible_return(CallJavaNode* call, uint k) {
2407   return call->tf()->domain_sig()->field_at(k)->is_instptr()->instance_klass() == call->tf()->range_sig()->field_at(TypeFunc::Parms)->is_instptr()->instance_klass();
2408 }
2409 
2410 void ConnectionGraph::process_call_arguments(CallNode *call) {
2411     bool is_arraycopy = false;
2412     switch (call->Opcode()) {
2413 #ifdef ASSERT
2414     case Op_Allocate:
2415     case Op_AllocateArray:
2416     case Op_Lock:
2417     case Op_Unlock:
2418       assert(false, "should be done already");
2419       break;
2420 #endif
2421     case Op_ArrayCopy:
2422     case Op_CallLeafNoFP:
2423       // Most array copies are ArrayCopy nodes at this point but there
2424       // are still a few direct calls to the copy subroutines (See
2425       // PhaseStringOpts::copy_string())
2426       is_arraycopy = (call->Opcode() == Op_ArrayCopy) ||
2427         call->as_CallLeaf()->is_call_to_arraycopystub();
2428       // fall through
2429     case Op_CallLeafVector:
2430     case Op_CallLeaf: {
2431       // Stub calls, objects do not escape but they are not scale replaceable.
2432       // Adjust escape state for outgoing arguments.
2433       const TypeTuple * d = call->tf()->domain_sig();
2434       bool src_has_oops = false;
2435       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2436         const Type* at = d->field_at(i);
2437         Node *arg = call->in(i);
2438         if (arg == nullptr) {
2439           continue;
2440         }
2441         const Type *aat = _igvn->type(arg);
2442         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr()) {
2443           continue;
2444         }
2445         if (arg->is_AddP()) {
2446           //
2447           // The inline_native_clone() case when the arraycopy stub is called
2448           // after the allocation before Initialize and CheckCastPP nodes.
2449           // Or normal arraycopy for object arrays case.
2450           //
2451           // Set AddP's base (Allocate) as not scalar replaceable since
2452           // pointer to the base (with offset) is passed as argument.
2453           //
2454           arg = get_addp_base(arg);
2455         }
2456         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
2457         assert(arg_ptn != nullptr, "should be registered");
2458         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
2459         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
2460           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
2461                  aat->isa_ptr() != nullptr, "expecting an Ptr");
2462           bool arg_has_oops = aat->isa_oopptr() &&
2463                               (aat->isa_instptr() ||
2464                                (aat->isa_aryptr() && (aat->isa_aryptr()->elem() == Type::BOTTOM || aat->isa_aryptr()->elem()->make_oopptr() != nullptr)) ||
2465                                (aat->isa_aryptr() && aat->isa_aryptr()->elem() != nullptr &&
2466                                                                aat->isa_aryptr()->is_flat() &&
2467                                                                aat->isa_aryptr()->elem()->inline_klass()->contains_oops()));
2468           if (i == TypeFunc::Parms) {
2469             src_has_oops = arg_has_oops;
2470           }
2471           //
2472           // src or dst could be j.l.Object when other is basic type array:
2473           //
2474           //   arraycopy(char[],0,Object*,0,size);
2475           //   arraycopy(Object*,0,char[],0,size);
2476           //
2477           // Don't add edges in such cases.
2478           //
2479           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
2480                                        arg_has_oops && (i > TypeFunc::Parms);
2481 #ifdef ASSERT
2482           if (!(is_arraycopy ||
2483                 BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(call) ||
2484                 (call->as_CallLeaf()->_name != nullptr &&
2485                  (strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
2486                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32C") == 0 ||
2487                   strcmp(call->as_CallLeaf()->_name, "updateBytesAdler32") == 0 ||
2488                   strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
2489                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
2490                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
2491                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
2492                   strcmp(call->as_CallLeaf()->_name, "electronicCodeBook_encryptAESCrypt") == 0 ||
2493                   strcmp(call->as_CallLeaf()->_name, "electronicCodeBook_decryptAESCrypt") == 0 ||
2494                   strcmp(call->as_CallLeaf()->_name, "counterMode_AESCrypt") == 0 ||
2495                   strcmp(call->as_CallLeaf()->_name, "galoisCounterMode_AESCrypt") == 0 ||
2496                   strcmp(call->as_CallLeaf()->_name, "poly1305_processBlocks") == 0 ||
2497                   strcmp(call->as_CallLeaf()->_name, "intpoly_montgomeryMult_P256") == 0 ||
2498                   strcmp(call->as_CallLeaf()->_name, "intpoly_assign") == 0 ||
2499                   strcmp(call->as_CallLeaf()->_name, "ghash_processBlocks") == 0 ||
2500                   strcmp(call->as_CallLeaf()->_name, "chacha20Block") == 0 ||
2501                   strcmp(call->as_CallLeaf()->_name, "kyberNtt") == 0 ||
2502                   strcmp(call->as_CallLeaf()->_name, "kyberInverseNtt") == 0 ||
2503                   strcmp(call->as_CallLeaf()->_name, "kyberNttMult") == 0 ||
2504                   strcmp(call->as_CallLeaf()->_name, "kyberAddPoly_2") == 0 ||
2505                   strcmp(call->as_CallLeaf()->_name, "kyberAddPoly_3") == 0 ||
2506                   strcmp(call->as_CallLeaf()->_name, "kyber12To16") == 0 ||
2507                   strcmp(call->as_CallLeaf()->_name, "kyberBarrettReduce") == 0 ||
2508                   strcmp(call->as_CallLeaf()->_name, "dilithiumAlmostNtt") == 0 ||
2509                   strcmp(call->as_CallLeaf()->_name, "dilithiumAlmostInverseNtt") == 0 ||
2510                   strcmp(call->as_CallLeaf()->_name, "dilithiumNttMult") == 0 ||
2511                   strcmp(call->as_CallLeaf()->_name, "dilithiumMontMulByConstant") == 0 ||
2512                   strcmp(call->as_CallLeaf()->_name, "dilithiumDecomposePoly") == 0 ||
2513                   strcmp(call->as_CallLeaf()->_name, "encodeBlock") == 0 ||
2514                   strcmp(call->as_CallLeaf()->_name, "decodeBlock") == 0 ||
2515                   strcmp(call->as_CallLeaf()->_name, "md5_implCompress") == 0 ||
2516                   strcmp(call->as_CallLeaf()->_name, "md5_implCompressMB") == 0 ||
2517                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
2518                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
2519                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
2520                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
2521                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
2522                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
2523                   strcmp(call->as_CallLeaf()->_name, "sha3_implCompress") == 0 ||
2524                   strcmp(call->as_CallLeaf()->_name, "double_keccak") == 0 ||
2525                   strcmp(call->as_CallLeaf()->_name, "sha3_implCompressMB") == 0 ||
2526                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
2527                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
2528                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0 ||
2529                   strcmp(call->as_CallLeaf()->_name, "montgomery_multiply") == 0 ||
2530                   strcmp(call->as_CallLeaf()->_name, "montgomery_square") == 0 ||
2531                   strcmp(call->as_CallLeaf()->_name, "vectorizedMismatch") == 0 ||
2532                   strcmp(call->as_CallLeaf()->_name, "load_unknown_inline") == 0 ||
2533                   strcmp(call->as_CallLeaf()->_name, "store_unknown_inline") == 0 ||
2534                   strcmp(call->as_CallLeaf()->_name, "store_inline_type_fields_to_buf") == 0 ||
2535                   strcmp(call->as_CallLeaf()->_name, "bigIntegerRightShiftWorker") == 0 ||
2536                   strcmp(call->as_CallLeaf()->_name, "bigIntegerLeftShiftWorker") == 0 ||
2537                   strcmp(call->as_CallLeaf()->_name, "vectorizedMismatch") == 0 ||
2538                   strcmp(call->as_CallLeaf()->_name, "stringIndexOf") == 0 ||
2539                   strcmp(call->as_CallLeaf()->_name, "arraysort_stub") == 0 ||
2540                   strcmp(call->as_CallLeaf()->_name, "array_partition_stub") == 0 ||
2541                   strcmp(call->as_CallLeaf()->_name, "get_class_id_intrinsic") == 0 ||
2542                   strcmp(call->as_CallLeaf()->_name, "unsafe_setmemory") == 0)
2543                  ))) {
2544             call->dump();
2545             fatal("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name);
2546           }
2547 #endif
2548           // Always process arraycopy's destination object since
2549           // we need to add all possible edges to references in
2550           // source object.
2551           if (arg_esc >= PointsToNode::ArgEscape &&
2552               !arg_is_arraycopy_dest) {
2553             continue;
2554           }
2555           PointsToNode::EscapeState es = PointsToNode::ArgEscape;
2556           if (call->is_ArrayCopy()) {
2557             ArrayCopyNode* ac = call->as_ArrayCopy();
2558             if (ac->is_clonebasic() ||
2559                 ac->is_arraycopy_validated() ||
2560                 ac->is_copyof_validated() ||
2561                 ac->is_copyofrange_validated()) {
2562               es = PointsToNode::NoEscape;
2563             }
2564           }
2565           set_escape_state(arg_ptn, es NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2566           if (arg_is_arraycopy_dest) {
2567             Node* src = call->in(TypeFunc::Parms);
2568             if (src->is_AddP()) {
2569               src = get_addp_base(src);
2570             }
2571             PointsToNode* src_ptn = ptnode_adr(src->_idx);
2572             assert(src_ptn != nullptr, "should be registered");
2573             // Special arraycopy edge:
2574             // Only escape state of destination object's fields affects
2575             // escape state of fields in source object.
2576             add_arraycopy(call, es, src_ptn, arg_ptn);
2577           }
2578         }
2579       }
2580       break;
2581     }
2582     case Op_CallStaticJava: {
2583       // For a static call, we know exactly what method is being called.
2584       // Use bytecode estimator to record the call's escape affects
2585 #ifdef ASSERT
2586       const char* name = call->as_CallStaticJava()->_name;
2587       assert((name == nullptr || strcmp(name, "uncommon_trap") != 0), "normal calls only");
2588 #endif
2589       ciMethod* meth = call->as_CallJava()->method();
2590       if ((meth != nullptr) && meth->is_boxing_method()) {
2591         break; // Boxing methods do not modify any oops.
2592       }
2593       BCEscapeAnalyzer* call_analyzer = (meth !=nullptr) ? meth->get_bcea() : nullptr;
2594       // fall-through if not a Java method or no analyzer information
2595       if (call_analyzer != nullptr) {
2596         PointsToNode* call_ptn = ptnode_adr(call->_idx);
2597         bool ret_arg = returns_an_argument(call);
2598         for (DomainIterator di(call->as_CallJava()); di.has_next(); di.next()) {
2599           int k = di.i_domain() - TypeFunc::Parms;
2600           const Type* at = di.current_domain_cc();
2601           Node* arg = call->in(di.i_domain_cc());
2602           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
2603           assert(!call_analyzer->is_arg_returned(k) || !meth->is_scalarized_arg(k) ||
2604                  !compatible_return(call->as_CallJava(), di.i_domain()) ||
2605                  call->proj_out_or_null(di.i_domain_cc() - di.first_field_pos() + TypeFunc::Parms + 1) == nullptr ||
2606                  _igvn->type(call->proj_out_or_null(di.i_domain_cc() - di.first_field_pos() + TypeFunc::Parms + 1)) == at,
2607                  "scalarized return and scalarized argument should match");
2608           if (at->isa_ptr() != nullptr && call_analyzer->is_arg_returned(k) && ret_arg) {
2609             // The call returns arguments.
2610             if (meth->is_scalarized_arg(k)) {
2611               ProjNode* res_proj = call->proj_out_or_null(di.i_domain_cc() - di.first_field_pos() + TypeFunc::Parms + 1);
2612               if (res_proj != nullptr) {
2613                 assert(_igvn->type(res_proj)->isa_ptr(), "scalarized return and scalarized argument should match");
2614                 if (res_proj->_con != TypeFunc::Parms) {
2615                   // add an edge between the result projection for a field and the argument projection for the same argument field
2616                   PointsToNode* proj_ptn = ptnode_adr(res_proj->_idx);
2617                   add_edge(proj_ptn, arg_ptn);
2618                   if (!call_analyzer->is_return_local()) {
2619                     add_edge(proj_ptn, phantom_obj);
2620                   }
2621                 }
2622               }
2623             } else if (call_ptn != nullptr) { // Is call's result used?
2624               assert(call_ptn->is_LocalVar(), "node should be registered");
2625               assert(arg_ptn != nullptr, "node should be registered");
2626               add_edge(call_ptn, arg_ptn);
2627             }
2628           }
2629           if (at->isa_oopptr() != nullptr &&
2630               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
2631             if (!call_analyzer->is_arg_stack(k)) {
2632               // The argument global escapes
2633               set_escape_state(arg_ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2634             } else {
2635               set_escape_state(arg_ptn, PointsToNode::ArgEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2636               if (!call_analyzer->is_arg_local(k)) {
2637                 // The argument itself doesn't escape, but any fields might
2638                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2639               }
2640             }
2641           }
2642         }
2643         if (call_ptn != nullptr && call_ptn->is_LocalVar()) {
2644           // The call returns arguments.
2645           assert(call_ptn->edge_count() > 0, "sanity");
2646           if (!call_analyzer->is_return_local()) {
2647             // Returns also unknown object.
2648             add_edge(call_ptn, phantom_obj);
2649           }
2650         }
2651         break;
2652       }
2653     }
2654     default: {
2655       // Fall-through here if not a Java method or no analyzer information
2656       // or some other type of call, assume the worst case: all arguments
2657       // globally escape.
2658       const TypeTuple* d = call->tf()->domain_cc();
2659       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
2660         const Type* at = d->field_at(i);
2661         if (at->isa_oopptr() != nullptr) {
2662           Node* arg = call->in(i);
2663           if (arg->is_AddP()) {
2664             arg = get_addp_base(arg);
2665           }
2666           assert(ptnode_adr(arg->_idx) != nullptr, "should be defined already");
2667           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape NOT_PRODUCT(COMMA trace_arg_escape_message(call)));
2668         }
2669       }
2670     }
2671   }
2672 }
2673 
2674 
2675 // Finish Graph construction.
2676 bool ConnectionGraph::complete_connection_graph(
2677                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
2678                          GrowableArray<JavaObjectNode*>& non_escaped_allocs_worklist,
2679                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
2680                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
2681   // Normally only 1-3 passes needed to build Connection Graph depending
2682   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
2683   // Set limit to 20 to catch situation when something did go wrong and
2684   // bailout Escape Analysis.
2685   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
2686 #define GRAPH_BUILD_ITER_LIMIT 20
2687 
2688   // Propagate GlobalEscape and ArgEscape escape states and check that
2689   // we still have non-escaping objects. The method pushs on _worklist
2690   // Field nodes which reference phantom_object.
2691   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_allocs_worklist)) {
2692     return false; // Nothing to do.
2693   }
2694   // Now propagate references to all JavaObject nodes.
2695   int java_objects_length = java_objects_worklist.length();
2696   elapsedTimer build_time;
2697   build_time.start();
2698   elapsedTimer time;
2699   bool timeout = false;
2700   int new_edges = 1;
2701   int iterations = 0;
2702   do {
2703     while ((new_edges > 0) &&
2704            (iterations++ < GRAPH_BUILD_ITER_LIMIT)) {
2705       double start_time = time.seconds();
2706       time.start();
2707       new_edges = 0;
2708       // Propagate references to phantom_object for nodes pushed on _worklist
2709       // by find_non_escaped_objects() and find_field_value().
2710       new_edges += add_java_object_edges(phantom_obj, false);
2711       for (int next = 0; next < java_objects_length; ++next) {
2712         JavaObjectNode* ptn = java_objects_worklist.at(next);
2713         new_edges += add_java_object_edges(ptn, true);
2714 
2715 #define SAMPLE_SIZE 4
2716         if ((next % SAMPLE_SIZE) == 0) {
2717           // Each 4 iterations calculate how much time it will take
2718           // to complete graph construction.
2719           time.stop();
2720           // Poll for requests from shutdown mechanism to quiesce compiler
2721           // because Connection graph construction may take long time.
2722           CompileBroker::maybe_block();
2723           double stop_time = time.seconds();
2724           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
2725           double time_until_end = time_per_iter * (double)(java_objects_length - next);
2726           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
2727             timeout = true;
2728             break; // Timeout
2729           }
2730           start_time = stop_time;
2731           time.start();
2732         }
2733 #undef SAMPLE_SIZE
2734 
2735       }
2736       if (timeout) break;
2737       if (new_edges > 0) {
2738         // Update escape states on each iteration if graph was updated.
2739         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_allocs_worklist)) {
2740           return false; // Nothing to do.
2741         }
2742       }
2743       time.stop();
2744       if (time.seconds() >= EscapeAnalysisTimeout) {
2745         timeout = true;
2746         break;
2747       }
2748       _compile->print_method(PHASE_EA_COMPLETE_CONNECTION_GRAPH_ITER, 5);
2749     }
2750     if ((iterations < GRAPH_BUILD_ITER_LIMIT) && !timeout) {
2751       time.start();
2752       // Find fields which have unknown value.
2753       int fields_length = oop_fields_worklist.length();
2754       for (int next = 0; next < fields_length; next++) {
2755         FieldNode* field = oop_fields_worklist.at(next);
2756         if (field->edge_count() == 0) {
2757           new_edges += find_field_value(field);
2758           // This code may added new edges to phantom_object.
2759           // Need an other cycle to propagate references to phantom_object.
2760         }
2761       }
2762       time.stop();
2763       if (time.seconds() >= EscapeAnalysisTimeout) {
2764         timeout = true;
2765         break;
2766       }
2767     } else {
2768       new_edges = 0; // Bailout
2769     }
2770   } while (new_edges > 0);
2771 
2772   build_time.stop();
2773   _build_time = build_time.seconds();
2774   _build_iterations = iterations;
2775 
2776   // Bailout if passed limits.
2777   if ((iterations >= GRAPH_BUILD_ITER_LIMIT) || timeout) {
2778     Compile* C = _compile;
2779     if (C->log() != nullptr) {
2780       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
2781       C->log()->text("%s", timeout ? "time" : "iterations");
2782       C->log()->end_elem(" limit'");
2783     }
2784     assert(ExitEscapeAnalysisOnTimeout, "infinite EA connection graph build during invocation %d (%f sec, %d iterations) with %d nodes and worklist size %d",
2785            _invocation, _build_time, _build_iterations, nodes_size(), ptnodes_worklist.length());
2786     // Possible infinite build_connection_graph loop,
2787     // bailout (no changes to ideal graph were made).
2788     return false;
2789   }
2790 
2791 #undef GRAPH_BUILD_ITER_LIMIT
2792 
2793   // Find fields initialized by null for non-escaping Allocations.
2794   int non_escaped_length = non_escaped_allocs_worklist.length();
2795   for (int next = 0; next < non_escaped_length; next++) {
2796     JavaObjectNode* ptn = non_escaped_allocs_worklist.at(next);
2797     PointsToNode::EscapeState es = ptn->escape_state();
2798     assert(es <= PointsToNode::ArgEscape, "sanity");
2799     if (es == PointsToNode::NoEscape) {
2800       if (find_init_values_null(ptn, _igvn) > 0) {
2801         // Adding references to null object does not change escape states
2802         // since it does not escape. Also no fields are added to null object.
2803         add_java_object_edges(null_obj, false);
2804       }
2805     }
2806     Node* n = ptn->ideal_node();
2807     if (n->is_Allocate()) {
2808       // The object allocated by this Allocate node will never be
2809       // seen by an other thread. Mark it so that when it is
2810       // expanded no MemBarStoreStore is added.
2811       InitializeNode* ini = n->as_Allocate()->initialization();
2812       if (ini != nullptr)
2813         ini->set_does_not_escape();
2814     }
2815   }
2816   return true; // Finished graph construction.
2817 }
2818 
2819 // Propagate GlobalEscape and ArgEscape escape states to all nodes
2820 // and check that we still have non-escaping java objects.
2821 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
2822                                                GrowableArray<JavaObjectNode*>& non_escaped_allocs_worklist,
2823                                                bool print_method) {
2824   GrowableArray<PointsToNode*> escape_worklist;
2825   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
2826   int ptnodes_length = ptnodes_worklist.length();
2827   for (int next = 0; next < ptnodes_length; ++next) {
2828     PointsToNode* ptn = ptnodes_worklist.at(next);
2829     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
2830         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
2831       escape_worklist.push(ptn);
2832     }
2833   }
2834   // Set escape states to referenced nodes (edges list).
2835   while (escape_worklist.length() > 0) {
2836     PointsToNode* ptn = escape_worklist.pop();
2837     PointsToNode::EscapeState es  = ptn->escape_state();
2838     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
2839     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
2840         es >= PointsToNode::ArgEscape) {
2841       // GlobalEscape or ArgEscape state of field means it has unknown value.
2842       if (add_edge(ptn, phantom_obj)) {
2843         // New edge was added
2844         add_field_uses_to_worklist(ptn->as_Field());
2845       }
2846     }
2847     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2848       PointsToNode* e = i.get();
2849       if (e->is_Arraycopy()) {
2850         assert(ptn->arraycopy_dst(), "sanity");
2851         // Propagate only fields escape state through arraycopy edge.
2852         if (e->fields_escape_state() < field_es) {
2853           set_fields_escape_state(e, field_es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2854           escape_worklist.push(e);
2855         }
2856       } else if (es >= field_es) {
2857         // fields_escape_state is also set to 'es' if it is less than 'es'.
2858         if (e->escape_state() < es) {
2859           set_escape_state(e, es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2860           escape_worklist.push(e);
2861         }
2862       } else {
2863         // Propagate field escape state.
2864         bool es_changed = false;
2865         if (e->fields_escape_state() < field_es) {
2866           set_fields_escape_state(e, field_es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2867           es_changed = true;
2868         }
2869         if ((e->escape_state() < field_es) &&
2870             e->is_Field() && ptn->is_JavaObject() &&
2871             e->as_Field()->is_oop()) {
2872           // Change escape state of referenced fields.
2873           set_escape_state(e, field_es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2874           es_changed = true;
2875         } else if (e->escape_state() < es) {
2876           set_escape_state(e, es NOT_PRODUCT(COMMA trace_propagate_message(ptn)));
2877           es_changed = true;
2878         }
2879         if (es_changed) {
2880           escape_worklist.push(e);
2881         }
2882       }
2883       if (print_method) {
2884         _compile->print_method(PHASE_EA_CONNECTION_GRAPH_PROPAGATE_ITER, 6, e->ideal_node());
2885       }
2886     }
2887   }
2888   // Remove escaped objects from non_escaped list.
2889   for (int next = non_escaped_allocs_worklist.length()-1; next >= 0 ; --next) {
2890     JavaObjectNode* ptn = non_escaped_allocs_worklist.at(next);
2891     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
2892       non_escaped_allocs_worklist.delete_at(next);
2893     }
2894     if (ptn->escape_state() == PointsToNode::NoEscape) {
2895       // Find fields in non-escaped allocations which have unknown value.
2896       find_init_values_phantom(ptn);
2897     }
2898   }
2899   return (non_escaped_allocs_worklist.length() > 0);
2900 }
2901 
2902 // Add all references to JavaObject node by walking over all uses.
2903 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
2904   int new_edges = 0;
2905   if (populate_worklist) {
2906     // Populate _worklist by uses of jobj's uses.
2907     for (UseIterator i(jobj); i.has_next(); i.next()) {
2908       PointsToNode* use = i.get();
2909       if (use->is_Arraycopy()) {
2910         continue;
2911       }
2912       add_uses_to_worklist(use);
2913       if (use->is_Field() && use->as_Field()->is_oop()) {
2914         // Put on worklist all field's uses (loads) and
2915         // related field nodes (same base and offset).
2916         add_field_uses_to_worklist(use->as_Field());
2917       }
2918     }
2919   }
2920   for (int l = 0; l < _worklist.length(); l++) {
2921     PointsToNode* use = _worklist.at(l);
2922     if (PointsToNode::is_base_use(use)) {
2923       // Add reference from jobj to field and from field to jobj (field's base).
2924       use = PointsToNode::get_use_node(use)->as_Field();
2925       if (add_base(use->as_Field(), jobj)) {
2926         new_edges++;
2927       }
2928       continue;
2929     }
2930     assert(!use->is_JavaObject(), "sanity");
2931     if (use->is_Arraycopy()) {
2932       if (jobj == null_obj) { // null object does not have field edges
2933         continue;
2934       }
2935       // Added edge from Arraycopy node to arraycopy's source java object
2936       if (add_edge(use, jobj)) {
2937         jobj->set_arraycopy_src();
2938         new_edges++;
2939       }
2940       // and stop here.
2941       continue;
2942     }
2943     if (!add_edge(use, jobj)) {
2944       continue; // No new edge added, there was such edge already.
2945     }
2946     new_edges++;
2947     if (use->is_LocalVar()) {
2948       add_uses_to_worklist(use);
2949       if (use->arraycopy_dst()) {
2950         for (EdgeIterator i(use); i.has_next(); i.next()) {
2951           PointsToNode* e = i.get();
2952           if (e->is_Arraycopy()) {
2953             if (jobj == null_obj) { // null object does not have field edges
2954               continue;
2955             }
2956             // Add edge from arraycopy's destination java object to Arraycopy node.
2957             if (add_edge(jobj, e)) {
2958               new_edges++;
2959               jobj->set_arraycopy_dst();
2960             }
2961           }
2962         }
2963       }
2964     } else {
2965       // Added new edge to stored in field values.
2966       // Put on worklist all field's uses (loads) and
2967       // related field nodes (same base and offset).
2968       add_field_uses_to_worklist(use->as_Field());
2969     }
2970   }
2971   _worklist.clear();
2972   _in_worklist.reset();
2973   return new_edges;
2974 }
2975 
2976 // Put on worklist all related field nodes.
2977 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
2978   assert(field->is_oop(), "sanity");
2979   int offset = field->offset();
2980   add_uses_to_worklist(field);
2981   // Loop over all bases of this field and push on worklist Field nodes
2982   // with the same offset and base (since they may reference the same field).
2983   for (BaseIterator i(field); i.has_next(); i.next()) {
2984     PointsToNode* base = i.get();
2985     add_fields_to_worklist(field, base);
2986     // Check if the base was source object of arraycopy and go over arraycopy's
2987     // destination objects since values stored to a field of source object are
2988     // accessible by uses (loads) of fields of destination objects.
2989     if (base->arraycopy_src()) {
2990       for (UseIterator j(base); j.has_next(); j.next()) {
2991         PointsToNode* arycp = j.get();
2992         if (arycp->is_Arraycopy()) {
2993           for (UseIterator k(arycp); k.has_next(); k.next()) {
2994             PointsToNode* abase = k.get();
2995             if (abase->arraycopy_dst() && abase != base) {
2996               // Look for the same arraycopy reference.
2997               add_fields_to_worklist(field, abase);
2998             }
2999           }
3000         }
3001       }
3002     }
3003   }
3004 }
3005 
3006 // Put on worklist all related field nodes.
3007 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
3008   int offset = field->offset();
3009   if (base->is_LocalVar()) {
3010     for (UseIterator j(base); j.has_next(); j.next()) {
3011       PointsToNode* f = j.get();
3012       if (PointsToNode::is_base_use(f)) { // Field
3013         f = PointsToNode::get_use_node(f);
3014         if (f == field || !f->as_Field()->is_oop()) {
3015           continue;
3016         }
3017         int offs = f->as_Field()->offset();
3018         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
3019           add_to_worklist(f);
3020         }
3021       }
3022     }
3023   } else {
3024     assert(base->is_JavaObject(), "sanity");
3025     if (// Skip phantom_object since it is only used to indicate that
3026         // this field's content globally escapes.
3027         (base != phantom_obj) &&
3028         // null object node does not have fields.
3029         (base != null_obj)) {
3030       for (EdgeIterator i(base); i.has_next(); i.next()) {
3031         PointsToNode* f = i.get();
3032         // Skip arraycopy edge since store to destination object field
3033         // does not update value in source object field.
3034         if (f->is_Arraycopy()) {
3035           assert(base->arraycopy_dst(), "sanity");
3036           continue;
3037         }
3038         if (f == field || !f->as_Field()->is_oop()) {
3039           continue;
3040         }
3041         int offs = f->as_Field()->offset();
3042         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
3043           add_to_worklist(f);
3044         }
3045       }
3046     }
3047   }
3048 }
3049 
3050 // Find fields which have unknown value.
3051 int ConnectionGraph::find_field_value(FieldNode* field) {
3052   // Escaped fields should have init value already.
3053   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
3054   int new_edges = 0;
3055   for (BaseIterator i(field); i.has_next(); i.next()) {
3056     PointsToNode* base = i.get();
3057     if (base->is_JavaObject()) {
3058       // Skip Allocate's fields which will be processed later.
3059       if (base->ideal_node()->is_Allocate()) {
3060         return 0;
3061       }
3062       assert(base == null_obj, "only null ptr base expected here");
3063     }
3064   }
3065   if (add_edge(field, phantom_obj)) {
3066     // New edge was added
3067     new_edges++;
3068     add_field_uses_to_worklist(field);
3069   }
3070   return new_edges;
3071 }
3072 
3073 // Find fields initializing values for allocations.
3074 int ConnectionGraph::find_init_values_phantom(JavaObjectNode* pta) {
3075   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
3076   PointsToNode* init_val = phantom_obj;
3077   Node* alloc = pta->ideal_node();
3078 
3079   // Do nothing for Allocate nodes since its fields values are
3080   // "known" unless they are initialized by arraycopy/clone.
3081   if (alloc->is_Allocate() && !pta->arraycopy_dst()) {
3082     if (alloc->as_Allocate()->in(AllocateNode::InitValue) != nullptr) {
3083       // Null-free inline type arrays are initialized with an init value instead of null
3084       init_val = ptnode_adr(alloc->as_Allocate()->in(AllocateNode::InitValue)->_idx);
3085       assert(init_val != nullptr, "init value should be registered");
3086     } else {
3087       return 0;
3088     }
3089   }
3090   // Non-escaped allocation returned from Java or runtime call has unknown values in fields.
3091   assert(pta->arraycopy_dst() || alloc->is_CallStaticJava() || init_val != phantom_obj, "sanity");
3092 #ifdef ASSERT
3093   if (alloc->is_CallStaticJava() && alloc->as_CallStaticJava()->method() == nullptr) {
3094     const char* name = alloc->as_CallStaticJava()->_name;
3095     assert(alloc->as_CallStaticJava()->is_call_to_multianewarray_stub() ||
3096            strncmp(name, "load_unknown_inline", 19) == 0 ||
3097            strncmp(name, "store_inline_type_fields_to_buf", 31) == 0, "sanity");
3098   }
3099 #endif
3100   // Non-escaped allocation returned from Java or runtime call have unknown values in fields.
3101   int new_edges = 0;
3102   for (EdgeIterator i(pta); i.has_next(); i.next()) {
3103     PointsToNode* field = i.get();
3104     if (field->is_Field() && field->as_Field()->is_oop()) {
3105       if (add_edge(field, init_val)) {
3106         // New edge was added
3107         new_edges++;
3108         add_field_uses_to_worklist(field->as_Field());
3109       }
3110     }
3111   }
3112   return new_edges;
3113 }
3114 
3115 // Find fields initializing values for allocations.
3116 int ConnectionGraph::find_init_values_null(JavaObjectNode* pta, PhaseValues* phase) {
3117   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
3118   Node* alloc = pta->ideal_node();
3119   // Do nothing for Call nodes since its fields values are unknown.
3120   if (!alloc->is_Allocate() || alloc->as_Allocate()->in(AllocateNode::InitValue) != nullptr) {
3121     return 0;
3122   }
3123   InitializeNode* ini = alloc->as_Allocate()->initialization();
3124   bool visited_bottom_offset = false;
3125   GrowableArray<int> offsets_worklist;
3126   int new_edges = 0;
3127 
3128   // Check if an oop field's initializing value is recorded and add
3129   // a corresponding null if field's value if it is not recorded.
3130   // Connection Graph does not record a default initialization by null
3131   // captured by Initialize node.
3132   //
3133   for (EdgeIterator i(pta); i.has_next(); i.next()) {
3134     PointsToNode* field = i.get(); // Field (AddP)
3135     if (!field->is_Field() || !field->as_Field()->is_oop()) {
3136       continue; // Not oop field
3137     }
3138     int offset = field->as_Field()->offset();
3139     if (offset == Type::OffsetBot) {
3140       if (!visited_bottom_offset) {
3141         // OffsetBot is used to reference array's element,
3142         // always add reference to null to all Field nodes since we don't
3143         // known which element is referenced.
3144         if (add_edge(field, null_obj)) {
3145           // New edge was added
3146           new_edges++;
3147           add_field_uses_to_worklist(field->as_Field());
3148           visited_bottom_offset = true;
3149         }
3150       }
3151     } else {
3152       // Check only oop fields.
3153       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
3154       if (adr_type->isa_rawptr()) {
3155 #ifdef ASSERT
3156         // Raw pointers are used for initializing stores so skip it
3157         // since it should be recorded already
3158         Node* base = get_addp_base(field->ideal_node());
3159         assert(adr_type->isa_rawptr() && is_captured_store_address(field->ideal_node()), "unexpected pointer type");
3160 #endif
3161         continue;
3162       }
3163       if (!offsets_worklist.contains(offset)) {
3164         offsets_worklist.append(offset);
3165         Node* value = nullptr;
3166         if (ini != nullptr) {
3167           // StoreP::value_basic_type() == T_ADDRESS
3168           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
3169           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
3170           // Make sure initializing store has the same type as this AddP.
3171           // This AddP may reference non existing field because it is on a
3172           // dead branch of bimorphic call which is not eliminated yet.
3173           if (store != nullptr && store->is_Store() &&
3174               store->as_Store()->value_basic_type() == ft) {
3175             value = store->in(MemNode::ValueIn);
3176 #ifdef ASSERT
3177             if (VerifyConnectionGraph) {
3178               // Verify that AddP already points to all objects the value points to.
3179               PointsToNode* val = ptnode_adr(value->_idx);
3180               assert((val != nullptr), "should be processed already");
3181               PointsToNode* missed_obj = nullptr;
3182               if (val->is_JavaObject()) {
3183                 if (!field->points_to(val->as_JavaObject())) {
3184                   missed_obj = val;
3185                 }
3186               } else {
3187                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
3188                   tty->print_cr("----------init store has invalid value -----");
3189                   store->dump();
3190                   val->dump();
3191                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
3192                 }
3193                 for (EdgeIterator j(val); j.has_next(); j.next()) {
3194                   PointsToNode* obj = j.get();
3195                   if (obj->is_JavaObject()) {
3196                     if (!field->points_to(obj->as_JavaObject())) {
3197                       missed_obj = obj;
3198                       break;
3199                     }
3200                   }
3201                 }
3202               }
3203               if (missed_obj != nullptr) {
3204                 tty->print_cr("----------field---------------------------------");
3205                 field->dump();
3206                 tty->print_cr("----------missed reference to object------------");
3207                 missed_obj->dump();
3208                 tty->print_cr("----------object referenced by init store-------");
3209                 store->dump();
3210                 val->dump();
3211                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
3212               }
3213             }
3214 #endif
3215           } else {
3216             // There could be initializing stores which follow allocation.
3217             // For example, a volatile field store is not collected
3218             // by Initialize node.
3219             //
3220             // Need to check for dependent loads to separate such stores from
3221             // stores which follow loads. For now, add initial value null so
3222             // that compare pointers optimization works correctly.
3223           }
3224         }
3225         if (value == nullptr) {
3226           // A field's initializing value was not recorded. Add null.
3227           if (add_edge(field, null_obj)) {
3228             // New edge was added
3229             new_edges++;
3230             add_field_uses_to_worklist(field->as_Field());
3231           }
3232         }
3233       }
3234     }
3235   }
3236   return new_edges;
3237 }
3238 
3239 // Adjust scalar_replaceable state after Connection Graph is built.
3240 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj, Unique_Node_List &reducible_merges) {
3241   // A Phi 'x' is a _candidate_ to be reducible if 'can_reduce_phi(x)'
3242   // returns true. If one of the constraints in this method set 'jobj' to NSR
3243   // then the candidate Phi is discarded. If the Phi has another SR 'jobj' as
3244   // input, 'adjust_scalar_replaceable_state' will eventually be called with
3245   // that other object and the Phi will become a reducible Phi.
3246   // There could be multiple merges involving the same jobj.
3247   Unique_Node_List candidates;
3248 
3249   // Search for non-escaping objects which are not scalar replaceable
3250   // and mark them to propagate the state to referenced objects.
3251 
3252   for (UseIterator i(jobj); i.has_next(); i.next()) {
3253     PointsToNode* use = i.get();
3254     if (use->is_Arraycopy()) {
3255       continue;
3256     }
3257     if (use->is_Field()) {
3258       FieldNode* field = use->as_Field();
3259       assert(field->is_oop() && field->scalar_replaceable(), "sanity");
3260       // 1. An object is not scalar replaceable if the field into which it is
3261       // stored has unknown offset (stored into unknown element of an array).
3262       if (field->offset() == Type::OffsetBot) {
3263         set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored at unknown offset"));
3264         return;
3265       }
3266       for (BaseIterator i(field); i.has_next(); i.next()) {
3267         PointsToNode* base = i.get();
3268         // 2. An object is not scalar replaceable if the field into which it is
3269         // stored has multiple bases one of which is null.
3270         if ((base == null_obj) && (field->base_count() > 1)) {
3271           set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with potentially null base"));
3272           return;
3273         }
3274         // 2.5. An object is not scalar replaceable if the field into which it is
3275         // stored has NSR base.
3276         if (!base->scalar_replaceable()) {
3277           set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with NSR base"));
3278           return;
3279         }
3280       }
3281     }
3282     assert(use->is_Field() || use->is_LocalVar(), "sanity");
3283     // 3. An object is not scalar replaceable if it is merged with other objects
3284     // and we can't remove the merge
3285     for (EdgeIterator j(use); j.has_next(); j.next()) {
3286       PointsToNode* ptn = j.get();
3287       if (ptn->is_JavaObject() && ptn != jobj) {
3288         Node* use_n = use->ideal_node();
3289 
3290         // These other local vars may point to multiple objects through a Phi
3291         // In this case we skip them and see if we can reduce the Phi.
3292         if (use_n->is_CastPP() || use_n->is_CheckCastPP()) {
3293           use_n = use_n->in(1);
3294         }
3295 
3296         // If it's already a candidate or confirmed reducible merge we can skip verification
3297         if (candidates.member(use_n) || reducible_merges.member(use_n)) {
3298           continue;
3299         }
3300 
3301         if (use_n->is_Phi() && can_reduce_phi(use_n->as_Phi())) {
3302           candidates.push(use_n);
3303         } else {
3304           // Mark all objects as NSR if we can't remove the merge
3305           set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA trace_merged_message(ptn)));
3306           set_not_scalar_replaceable(ptn NOT_PRODUCT(COMMA trace_merged_message(jobj)));
3307         }
3308       }
3309     }
3310     if (!jobj->scalar_replaceable()) {
3311       return;
3312     }
3313   }
3314 
3315   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
3316     if (j.get()->is_Arraycopy()) {
3317       continue;
3318     }
3319 
3320     // Non-escaping object node should point only to field nodes.
3321     FieldNode* field = j.get()->as_Field();
3322     int offset = field->as_Field()->offset();
3323 
3324     // 4. An object is not scalar replaceable if it has a field with unknown
3325     // offset (array's element is accessed in loop).
3326     if (offset == Type::OffsetBot) {
3327       set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "has field with unknown offset"));
3328       return;
3329     }
3330     // 5. Currently an object is not scalar replaceable if a LoadStore node
3331     // access its field since the field value is unknown after it.
3332     //
3333     Node* n = field->ideal_node();
3334 
3335     // Test for an unsafe access that was parsed as maybe off heap
3336     // (with a CheckCastPP to raw memory).
3337     assert(n->is_AddP(), "expect an address computation");
3338     if (n->in(AddPNode::Base)->is_top() &&
3339         n->in(AddPNode::Address)->Opcode() == Op_CheckCastPP) {
3340       assert(n->in(AddPNode::Address)->bottom_type()->isa_rawptr(), "raw address so raw cast expected");
3341       assert(_igvn->type(n->in(AddPNode::Address)->in(1))->isa_oopptr(), "cast pattern at unsafe access expected");
3342       set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is used as base of mixed unsafe access"));
3343       return;
3344     }
3345 
3346     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3347       Node* u = n->fast_out(i);
3348       if (u->is_LoadStore() || (u->is_Mem() && u->as_Mem()->is_mismatched_access())) {
3349         set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is used in LoadStore or mismatched access"));
3350         return;
3351       }
3352     }
3353 
3354     // 6. Or the address may point to more then one object. This may produce
3355     // the false positive result (set not scalar replaceable)
3356     // since the flow-insensitive escape analysis can't separate
3357     // the case when stores overwrite the field's value from the case
3358     // when stores happened on different control branches.
3359     //
3360     // Note: it will disable scalar replacement in some cases:
3361     //
3362     //    Point p[] = new Point[1];
3363     //    p[0] = new Point(); // Will be not scalar replaced
3364     //
3365     // but it will save us from incorrect optimizations in next cases:
3366     //
3367     //    Point p[] = new Point[1];
3368     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
3369     //
3370     if (field->base_count() > 1 && candidates.size() == 0) {
3371       if (has_non_reducible_merge(field, reducible_merges)) {
3372         for (BaseIterator i(field); i.has_next(); i.next()) {
3373           PointsToNode* base = i.get();
3374           // Don't take into account LocalVar nodes which
3375           // may point to only one object which should be also
3376           // this field's base by now.
3377           if (base->is_JavaObject() && base != jobj) {
3378             // Mark all bases.
3379             set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "may point to more than one object"));
3380             set_not_scalar_replaceable(base NOT_PRODUCT(COMMA "may point to more than one object"));
3381           }
3382         }
3383 
3384         if (!jobj->scalar_replaceable()) {
3385           return;
3386         }
3387       }
3388     }
3389   }
3390 
3391   // The candidate is truly a reducible merge only if none of the other
3392   // constraints ruled it as NSR. There could be multiple merges involving the
3393   // same jobj.
3394   assert(jobj->scalar_replaceable(), "sanity");
3395   for (uint i = 0; i < candidates.size(); i++ ) {
3396     Node* candidate = candidates.at(i);
3397     reducible_merges.push(candidate);
3398   }
3399 }
3400 
3401 bool ConnectionGraph::has_non_reducible_merge(FieldNode* field, Unique_Node_List& reducible_merges) {
3402   for (BaseIterator i(field); i.has_next(); i.next()) {
3403     Node* base = i.get()->ideal_node();
3404     if (base->is_Phi() && !reducible_merges.member(base)) {
3405       return true;
3406     }
3407   }
3408   return false;
3409 }
3410 
3411 void ConnectionGraph::revisit_reducible_phi_status(JavaObjectNode* jobj, Unique_Node_List& reducible_merges) {
3412   assert(jobj != nullptr && !jobj->scalar_replaceable(), "jobj should be set as NSR before calling this function.");
3413 
3414   // Look for 'phis' that refer to 'jobj' as the last
3415   // remaining scalar replaceable input.
3416   uint reducible_merges_cnt = reducible_merges.size();
3417   for (uint i = 0; i < reducible_merges_cnt; i++) {
3418     Node* phi = reducible_merges.at(i);
3419 
3420     // This 'Phi' will be a 'good' if it still points to
3421     // at least one scalar replaceable object. Note that 'obj'
3422     // was/should be marked as NSR before calling this function.
3423     bool good_phi = false;
3424 
3425     for (uint j = 1; j < phi->req(); j++) {
3426       JavaObjectNode* phi_in_obj = unique_java_object(phi->in(j));
3427       if (phi_in_obj != nullptr && phi_in_obj->scalar_replaceable()) {
3428         good_phi = true;
3429         break;
3430       }
3431     }
3432 
3433     if (!good_phi) {
3434       NOT_PRODUCT(if (TraceReduceAllocationMerges) tty->print_cr("Phi %d became non-reducible after node %d became NSR.", phi->_idx, jobj->ideal_node()->_idx);)
3435       reducible_merges.remove(i);
3436 
3437       // Decrement the index because the 'remove' call above actually
3438       // moves the last entry of the list to position 'i'.
3439       i--;
3440 
3441       reducible_merges_cnt--;
3442     }
3443   }
3444 }
3445 
3446 // Propagate NSR (Not scalar replaceable) state.
3447 void ConnectionGraph::find_scalar_replaceable_allocs(GrowableArray<JavaObjectNode*>& jobj_worklist, Unique_Node_List &reducible_merges) {
3448   int jobj_length = jobj_worklist.length();
3449   bool found_nsr_alloc = true;
3450   while (found_nsr_alloc) {
3451     found_nsr_alloc = false;
3452     for (int next = 0; next < jobj_length; ++next) {
3453       JavaObjectNode* jobj = jobj_worklist.at(next);
3454       for (UseIterator i(jobj); (jobj->scalar_replaceable() && i.has_next()); i.next()) {
3455         PointsToNode* use = i.get();
3456         if (use->is_Field()) {
3457           FieldNode* field = use->as_Field();
3458           assert(field->is_oop() && field->scalar_replaceable(), "sanity");
3459           assert(field->offset() != Type::OffsetBot, "sanity");
3460           for (BaseIterator i(field); i.has_next(); i.next()) {
3461             PointsToNode* base = i.get();
3462             // An object is not scalar replaceable if the field into which
3463             // it is stored has NSR base.
3464             if ((base != null_obj) && !base->scalar_replaceable()) {
3465               set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with NSR base"));
3466               // Any merge that had only 'jobj' as scalar-replaceable will now be non-reducible,
3467               // because there is no point in reducing a Phi that won't improve the number of SR
3468               // objects.
3469               revisit_reducible_phi_status(jobj, reducible_merges);
3470               found_nsr_alloc = true;
3471               break;
3472             }
3473           }
3474         } else if (use->is_LocalVar()) {
3475           Node* phi = use->ideal_node();
3476           if (phi->Opcode() == Op_Phi && reducible_merges.member(phi) && !can_reduce_phi(phi->as_Phi())) {
3477             set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is merged in a non-reducible phi"));
3478             reducible_merges.yank(phi);
3479             found_nsr_alloc = true;
3480             break;
3481           }
3482         }
3483         _compile->print_method(PHASE_EA_PROPAGATE_NSR_ITER, 5, jobj->ideal_node());
3484       }
3485     }
3486   }
3487 }
3488 
3489 #ifdef ASSERT
3490 void ConnectionGraph::verify_connection_graph(
3491                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
3492                          GrowableArray<JavaObjectNode*>& non_escaped_allocs_worklist,
3493                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
3494                          GrowableArray<Node*>& addp_worklist) {
3495   // Verify that graph is complete - no new edges could be added.
3496   int java_objects_length = java_objects_worklist.length();
3497   int non_escaped_length  = non_escaped_allocs_worklist.length();
3498   int new_edges = 0;
3499   for (int next = 0; next < java_objects_length; ++next) {
3500     JavaObjectNode* ptn = java_objects_worklist.at(next);
3501     new_edges += add_java_object_edges(ptn, true);
3502   }
3503   assert(new_edges == 0, "graph was not complete");
3504   // Verify that escape state is final.
3505   int length = non_escaped_allocs_worklist.length();
3506   find_non_escaped_objects(ptnodes_worklist, non_escaped_allocs_worklist, /*print_method=*/ false);
3507   assert((non_escaped_length == non_escaped_allocs_worklist.length()) &&
3508          (non_escaped_length == length) &&
3509          (_worklist.length() == 0), "escape state was not final");
3510 
3511   // Verify fields information.
3512   int addp_length = addp_worklist.length();
3513   for (int next = 0; next < addp_length; ++next ) {
3514     Node* n = addp_worklist.at(next);
3515     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
3516     if (field->is_oop()) {
3517       // Verify that field has all bases
3518       Node* base = get_addp_base(n);
3519       PointsToNode* ptn = ptnode_adr(base->_idx);
3520       if (ptn->is_JavaObject()) {
3521         assert(field->has_base(ptn->as_JavaObject()), "sanity");
3522       } else {
3523         assert(ptn->is_LocalVar(), "sanity");
3524         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
3525           PointsToNode* e = i.get();
3526           if (e->is_JavaObject()) {
3527             assert(field->has_base(e->as_JavaObject()), "sanity");
3528           }
3529         }
3530       }
3531       // Verify that all fields have initializing values.
3532       if (field->edge_count() == 0) {
3533         tty->print_cr("----------field does not have references----------");
3534         field->dump();
3535         for (BaseIterator i(field); i.has_next(); i.next()) {
3536           PointsToNode* base = i.get();
3537           tty->print_cr("----------field has next base---------------------");
3538           base->dump();
3539           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
3540             tty->print_cr("----------base has fields-------------------------");
3541             for (EdgeIterator j(base); j.has_next(); j.next()) {
3542               j.get()->dump();
3543             }
3544             tty->print_cr("----------base has references---------------------");
3545             for (UseIterator j(base); j.has_next(); j.next()) {
3546               j.get()->dump();
3547             }
3548           }
3549         }
3550         for (UseIterator i(field); i.has_next(); i.next()) {
3551           i.get()->dump();
3552         }
3553         assert(field->edge_count() > 0, "sanity");
3554       }
3555     }
3556   }
3557 }
3558 #endif
3559 
3560 // Optimize ideal graph.
3561 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
3562                                            GrowableArray<MemBarStoreStoreNode*>& storestore_worklist) {
3563   Compile* C = _compile;
3564   PhaseIterGVN* igvn = _igvn;
3565   if (EliminateLocks) {
3566     // Mark locks before changing ideal graph.
3567     int cnt = C->macro_count();
3568     for (int i = 0; i < cnt; i++) {
3569       Node *n = C->macro_node(i);
3570       if (n->is_AbstractLock()) { // Lock and Unlock nodes
3571         AbstractLockNode* alock = n->as_AbstractLock();
3572         if (!alock->is_non_esc_obj()) {
3573           const Type* obj_type = igvn->type(alock->obj_node());
3574           if (can_eliminate_lock(alock) && !obj_type->is_inlinetypeptr()) {
3575             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
3576             // The lock could be marked eliminated by lock coarsening
3577             // code during first IGVN before EA. Replace coarsened flag
3578             // to eliminate all associated locks/unlocks.
3579 #ifdef ASSERT
3580             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
3581 #endif
3582             alock->set_non_esc_obj();
3583           }
3584         }
3585       }
3586     }
3587   }
3588 
3589   if (OptimizePtrCompare) {
3590     for (int i = 0; i < ptr_cmp_worklist.length(); i++) {
3591       Node *n = ptr_cmp_worklist.at(i);
3592       assert(n->Opcode() == Op_CmpN || n->Opcode() == Op_CmpP, "must be");
3593       const TypeInt* tcmp = optimize_ptr_compare(n->in(1), n->in(2));
3594       if (tcmp->singleton()) {
3595         Node* cmp = igvn->makecon(tcmp);
3596 #ifndef PRODUCT
3597         if (PrintOptimizePtrCompare) {
3598           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"));
3599           if (Verbose) {
3600             n->dump(1);
3601           }
3602         }
3603 #endif
3604         igvn->replace_node(n, cmp);
3605       }
3606     }
3607   }
3608 
3609   // For MemBarStoreStore nodes added in library_call.cpp, check
3610   // escape status of associated AllocateNode and optimize out
3611   // MemBarStoreStore node if the allocated object never escapes.
3612   for (int i = 0; i < storestore_worklist.length(); i++) {
3613     Node* storestore = storestore_worklist.at(i);
3614     Node* alloc = storestore->in(MemBarNode::Precedent)->in(0);
3615     if (alloc->is_Allocate() && not_global_escape(alloc)) {
3616       if (alloc->in(AllocateNode::InlineType) != nullptr) {
3617         // Non-escaping inline type buffer allocations don't require a membar
3618         storestore->as_MemBar()->remove(_igvn);
3619       } else {
3620         MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
3621         mb->init_req(TypeFunc::Memory,  storestore->in(TypeFunc::Memory));
3622         mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
3623         igvn->register_new_node_with_optimizer(mb);
3624         igvn->replace_node(storestore, mb);
3625       }
3626     }
3627   }
3628 }
3629 
3630 // Atomic flat accesses on non-escaping objects can be optimized to non-atomic accesses
3631 void ConnectionGraph::optimize_flat_accesses(GrowableArray<SafePointNode*>& sfn_worklist) {
3632   PhaseIterGVN& igvn = *_igvn;
3633   bool delay = igvn.delay_transform();
3634   igvn.set_delay_transform(true);
3635   igvn.C->for_each_flat_access([&](Node* n) {
3636     Node* base = n->is_LoadFlat() ? n->as_LoadFlat()->base() : n->as_StoreFlat()->base();
3637     if (!not_global_escape(base)) {
3638       return;
3639     }
3640 
3641     bool expanded;
3642     if (n->is_LoadFlat()) {
3643       expanded = n->as_LoadFlat()->expand_non_atomic(igvn);
3644     } else {
3645       expanded = n->as_StoreFlat()->expand_non_atomic(igvn);
3646     }
3647     if (expanded) {
3648       sfn_worklist.remove(n->as_SafePoint());
3649       igvn.C->remove_flat_access(n);
3650     }
3651   });
3652   igvn.set_delay_transform(delay);
3653 }
3654 
3655 // Optimize objects compare.
3656 const TypeInt* ConnectionGraph::optimize_ptr_compare(Node* left, Node* right) {
3657   const TypeInt* UNKNOWN = TypeInt::CC;    // [-1, 0,1]
3658   if (!OptimizePtrCompare) {
3659     return UNKNOWN;
3660   }
3661   const TypeInt* EQ = TypeInt::CC_EQ; // [0] == ZERO
3662   const TypeInt* NE = TypeInt::CC_GT; // [1] == ONE
3663 
3664   PointsToNode* ptn1 = ptnode_adr(left->_idx);
3665   PointsToNode* ptn2 = ptnode_adr(right->_idx);
3666   JavaObjectNode* jobj1 = unique_java_object(left);
3667   JavaObjectNode* jobj2 = unique_java_object(right);
3668 
3669   // The use of this method during allocation merge reduction may cause 'left'
3670   // or 'right' be something (e.g., a Phi) that isn't in the connection graph or
3671   // that doesn't reference an unique java object.
3672   if (ptn1 == nullptr || ptn2 == nullptr ||
3673       jobj1 == nullptr || jobj2 == nullptr) {
3674     return UNKNOWN;
3675   }
3676 
3677   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
3678   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
3679 
3680   // Check simple cases first.
3681   if (jobj1 != nullptr) {
3682     if (jobj1->escape_state() == PointsToNode::NoEscape) {
3683       if (jobj1 == jobj2) {
3684         // Comparing the same not escaping object.
3685         return EQ;
3686       }
3687       Node* obj = jobj1->ideal_node();
3688       // Comparing not escaping allocation.
3689       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
3690           !ptn2->points_to(jobj1)) {
3691         return NE; // This includes nullness check.
3692       }
3693     }
3694   }
3695   if (jobj2 != nullptr) {
3696     if (jobj2->escape_state() == PointsToNode::NoEscape) {
3697       Node* obj = jobj2->ideal_node();
3698       // Comparing not escaping allocation.
3699       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
3700           !ptn1->points_to(jobj2)) {
3701         return NE; // This includes nullness check.
3702       }
3703     }
3704   }
3705   if (jobj1 != nullptr && jobj1 != phantom_obj &&
3706       jobj2 != nullptr && jobj2 != phantom_obj &&
3707       jobj1->ideal_node()->is_Con() &&
3708       jobj2->ideal_node()->is_Con()) {
3709     // Klass or String constants compare. Need to be careful with
3710     // compressed pointers - compare types of ConN and ConP instead of nodes.
3711     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
3712     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
3713     if (t1->make_ptr() == t2->make_ptr()) {
3714       return EQ;
3715     } else {
3716       return NE;
3717     }
3718   }
3719   if (ptn1->meet(ptn2)) {
3720     return UNKNOWN; // Sets are not disjoint
3721   }
3722 
3723   // Sets are disjoint.
3724   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
3725   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
3726   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
3727   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
3728   if ((set1_has_unknown_ptr && set2_has_null_ptr) ||
3729       (set2_has_unknown_ptr && set1_has_null_ptr)) {
3730     // Check nullness of unknown object.
3731     return UNKNOWN;
3732   }
3733 
3734   // Disjointness by itself is not sufficient since
3735   // alias analysis is not complete for escaped objects.
3736   // Disjoint sets are definitely unrelated only when
3737   // at least one set has only not escaping allocations.
3738   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
3739     if (ptn1->non_escaping_allocation()) {
3740       return NE;
3741     }
3742   }
3743   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
3744     if (ptn2->non_escaping_allocation()) {
3745       return NE;
3746     }
3747   }
3748   return UNKNOWN;
3749 }
3750 
3751 // Connection Graph construction functions.
3752 
3753 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
3754   PointsToNode* ptadr = _nodes.at(n->_idx);
3755   if (ptadr != nullptr) {
3756     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
3757     return;
3758   }
3759   Compile* C = _compile;
3760   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
3761   map_ideal_node(n, ptadr);
3762 }
3763 
3764 PointsToNode* ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
3765   PointsToNode* ptadr = _nodes.at(n->_idx);
3766   if (ptadr != nullptr) {
3767     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
3768     return ptadr;
3769   }
3770   Compile* C = _compile;
3771   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
3772   map_ideal_node(n, ptadr);
3773   return ptadr;
3774 }
3775 
3776 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
3777   PointsToNode* ptadr = _nodes.at(n->_idx);
3778   if (ptadr != nullptr) {
3779     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
3780     return;
3781   }
3782   bool unsafe = false;
3783   bool is_oop = is_oop_field(n, offset, &unsafe);
3784   if (unsafe) {
3785     es = PointsToNode::GlobalEscape;
3786   }
3787   Compile* C = _compile;
3788   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
3789   map_ideal_node(n, field);
3790 }
3791 
3792 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
3793                                     PointsToNode* src, PointsToNode* dst) {
3794   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
3795   assert((src != null_obj) && (dst != null_obj), "not for ConP null");
3796   PointsToNode* ptadr = _nodes.at(n->_idx);
3797   if (ptadr != nullptr) {
3798     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
3799     return;
3800   }
3801   Compile* C = _compile;
3802   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
3803   map_ideal_node(n, ptadr);
3804   // Add edge from arraycopy node to source object.
3805   (void)add_edge(ptadr, src);
3806   src->set_arraycopy_src();
3807   // Add edge from destination object to arraycopy node.
3808   (void)add_edge(dst, ptadr);
3809   dst->set_arraycopy_dst();
3810 }
3811 
3812 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
3813   const Type* adr_type = n->as_AddP()->bottom_type();
3814   int field_offset = adr_type->isa_aryptr() ? adr_type->isa_aryptr()->field_offset().get() : Type::OffsetBot;
3815   BasicType bt = T_INT;
3816   if (offset == Type::OffsetBot && field_offset == Type::OffsetBot) {
3817     // Check only oop fields.
3818     if (!adr_type->isa_aryptr() ||
3819         adr_type->isa_aryptr()->elem() == Type::BOTTOM ||
3820         adr_type->isa_aryptr()->elem()->make_oopptr() != nullptr) {
3821       // OffsetBot is used to reference array's element. Ignore first AddP.
3822       if (find_second_addp(n, n->in(AddPNode::Base)) == nullptr) {
3823         bt = T_OBJECT;
3824       }
3825     }
3826   } else if (offset != oopDesc::klass_offset_in_bytes()) {
3827     if (adr_type->isa_instptr()) {
3828       ciField* field = _compile->alias_type(adr_type->is_ptr())->field();
3829       if (field != nullptr) {
3830         bt = field->layout_type();
3831       } else {
3832         // Check for unsafe oop field access
3833         if (has_oop_node_outs(n)) {
3834           bt = T_OBJECT;
3835           (*unsafe) = true;
3836         }
3837       }
3838     } else if (adr_type->isa_aryptr()) {
3839       if (offset == arrayOopDesc::length_offset_in_bytes()) {
3840         // Ignore array length load.
3841       } else if (find_second_addp(n, n->in(AddPNode::Base)) != nullptr) {
3842         // Ignore first AddP.
3843       } else {
3844         const Type* elemtype = adr_type->is_aryptr()->elem();
3845         if (adr_type->is_aryptr()->is_flat() && field_offset != Type::OffsetBot) {
3846           ciInlineKlass* vk = elemtype->inline_klass();
3847           field_offset += vk->payload_offset();
3848           ciField* field = vk->get_field_by_offset(field_offset, false);
3849           if (field != nullptr) {
3850             bt = field->layout_type();
3851           } else {
3852             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);
3853             bt = T_BOOLEAN;
3854           }
3855         } else {
3856           bt = elemtype->array_element_basic_type();
3857         }
3858       }
3859     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
3860       // Allocation initialization, ThreadLocal field access, unsafe access
3861       if (has_oop_node_outs(n)) {
3862         bt = T_OBJECT;
3863       }
3864     }
3865   }
3866   // Note: T_NARROWOOP is not classed as a real reference type
3867   bool res = (is_reference_type(bt) || bt == T_NARROWOOP);
3868   assert(!has_oop_node_outs(n) || res, "sanity: AddP has oop outs, needs to be treated as oop field");
3869   return res;
3870 }
3871 
3872 bool ConnectionGraph::has_oop_node_outs(Node* n) {
3873   return n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN) ||
3874          n->has_out_with(Op_GetAndSetP, Op_GetAndSetN, Op_CompareAndExchangeP, Op_CompareAndExchangeN) ||
3875          n->has_out_with(Op_CompareAndSwapP, Op_CompareAndSwapN, Op_WeakCompareAndSwapP, Op_WeakCompareAndSwapN) ||
3876          BarrierSet::barrier_set()->barrier_set_c2()->escape_has_out_with_unsafe_object(n);
3877 }
3878 
3879 // Returns unique pointed java object or null.
3880 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) const {
3881   // If the node was created after the escape computation we can't answer.
3882   uint idx = n->_idx;
3883   if (idx >= nodes_size()) {
3884     return nullptr;
3885   }
3886   PointsToNode* ptn = ptnode_adr(idx);
3887   if (ptn == nullptr) {
3888     return nullptr;
3889   }
3890   if (ptn->is_JavaObject()) {
3891     return ptn->as_JavaObject();
3892   }
3893   assert(ptn->is_LocalVar(), "sanity");
3894   // Check all java objects it points to.
3895   JavaObjectNode* jobj = nullptr;
3896   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
3897     PointsToNode* e = i.get();
3898     if (e->is_JavaObject()) {
3899       if (jobj == nullptr) {
3900         jobj = e->as_JavaObject();
3901       } else if (jobj != e) {
3902         return nullptr;
3903       }
3904     }
3905   }
3906   return jobj;
3907 }
3908 
3909 // Return true if this node points only to non-escaping allocations.
3910 bool PointsToNode::non_escaping_allocation() {
3911   if (is_JavaObject()) {
3912     Node* n = ideal_node();
3913     if (n->is_Allocate() || n->is_CallStaticJava()) {
3914       return (escape_state() == PointsToNode::NoEscape);
3915     } else {
3916       return false;
3917     }
3918   }
3919   assert(is_LocalVar(), "sanity");
3920   // Check all java objects it points to.
3921   for (EdgeIterator i(this); i.has_next(); i.next()) {
3922     PointsToNode* e = i.get();
3923     if (e->is_JavaObject()) {
3924       Node* n = e->ideal_node();
3925       if ((e->escape_state() != PointsToNode::NoEscape) ||
3926           !(n->is_Allocate() || n->is_CallStaticJava())) {
3927         return false;
3928       }
3929     }
3930   }
3931   return true;
3932 }
3933 
3934 // Return true if we know the node does not escape globally.
3935 bool ConnectionGraph::not_global_escape(Node *n) {
3936   assert(!_collecting, "should not call during graph construction");
3937   // If the node was created after the escape computation we can't answer.
3938   uint idx = n->_idx;
3939   if (idx >= nodes_size()) {
3940     return false;
3941   }
3942   PointsToNode* ptn = ptnode_adr(idx);
3943   if (ptn == nullptr) {
3944     return false; // not in congraph (e.g. ConI)
3945   }
3946   PointsToNode::EscapeState es = ptn->escape_state();
3947   // If we have already computed a value, return it.
3948   if (es >= PointsToNode::GlobalEscape) {
3949     return false;
3950   }
3951   if (ptn->is_JavaObject()) {
3952     return true; // (es < PointsToNode::GlobalEscape);
3953   }
3954   assert(ptn->is_LocalVar(), "sanity");
3955   // Check all java objects it points to.
3956   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
3957     if (i.get()->escape_state() >= PointsToNode::GlobalEscape) {
3958       return false;
3959     }
3960   }
3961   return true;
3962 }
3963 
3964 // Return true if locked object does not escape globally
3965 // and locked code region (identified by BoxLockNode) is balanced:
3966 // all compiled code paths have corresponding Lock/Unlock pairs.
3967 bool ConnectionGraph::can_eliminate_lock(AbstractLockNode* alock) {
3968   if (alock->is_balanced() && not_global_escape(alock->obj_node())) {
3969     if (EliminateNestedLocks) {
3970       // We can mark whole locking region as Local only when only
3971       // one object is used for locking.
3972       alock->box_node()->as_BoxLock()->set_local();
3973     }
3974     return true;
3975   }
3976   return false;
3977 }
3978 
3979 // Helper functions
3980 
3981 // Return true if this node points to specified node or nodes it points to.
3982 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
3983   if (is_JavaObject()) {
3984     return (this == ptn);
3985   }
3986   assert(is_LocalVar() || is_Field(), "sanity");
3987   for (EdgeIterator i(this); i.has_next(); i.next()) {
3988     if (i.get() == ptn) {
3989       return true;
3990     }
3991   }
3992   return false;
3993 }
3994 
3995 // Return true if one node points to an other.
3996 bool PointsToNode::meet(PointsToNode* ptn) {
3997   if (this == ptn) {
3998     return true;
3999   } else if (ptn->is_JavaObject()) {
4000     return this->points_to(ptn->as_JavaObject());
4001   } else if (this->is_JavaObject()) {
4002     return ptn->points_to(this->as_JavaObject());
4003   }
4004   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
4005   int ptn_count =  ptn->edge_count();
4006   for (EdgeIterator i(this); i.has_next(); i.next()) {
4007     PointsToNode* this_e = i.get();
4008     for (int j = 0; j < ptn_count; j++) {
4009       if (this_e == ptn->edge(j)) {
4010         return true;
4011       }
4012     }
4013   }
4014   return false;
4015 }
4016 
4017 #ifdef ASSERT
4018 // Return true if bases point to this java object.
4019 bool FieldNode::has_base(JavaObjectNode* jobj) const {
4020   for (BaseIterator i(this); i.has_next(); i.next()) {
4021     if (i.get() == jobj) {
4022       return true;
4023     }
4024   }
4025   return false;
4026 }
4027 #endif
4028 
4029 bool ConnectionGraph::is_captured_store_address(Node* addp) {
4030   // Handle simple case first.
4031   assert(_igvn->type(addp)->isa_oopptr() == nullptr, "should be raw access");
4032   if (addp->in(AddPNode::Address)->is_Proj() && addp->in(AddPNode::Address)->in(0)->is_Allocate()) {
4033     return true;
4034   } else if (addp->in(AddPNode::Address)->is_Phi()) {
4035     for (DUIterator_Fast imax, i = addp->fast_outs(imax); i < imax; i++) {
4036       Node* addp_use = addp->fast_out(i);
4037       if (addp_use->is_Store()) {
4038         for (DUIterator_Fast jmax, j = addp_use->fast_outs(jmax); j < jmax; j++) {
4039           if (addp_use->fast_out(j)->is_Initialize()) {
4040             return true;
4041           }
4042         }
4043       }
4044     }
4045   }
4046   return false;
4047 }
4048 
4049 int ConnectionGraph::address_offset(Node* adr, PhaseValues* phase) {
4050   const Type *adr_type = phase->type(adr);
4051   if (adr->is_AddP() && adr_type->isa_oopptr() == nullptr && is_captured_store_address(adr)) {
4052     // We are computing a raw address for a store captured by an Initialize
4053     // compute an appropriate address type. AddP cases #3 and #5 (see below).
4054     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
4055     assert(offs != Type::OffsetBot ||
4056            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
4057            "offset must be a constant or it is initialization of array");
4058     return offs;
4059   }
4060   return adr_type->is_ptr()->flat_offset();


4061 }
4062 
4063 Node* ConnectionGraph::get_addp_base(Node *addp) {
4064   assert(addp->is_AddP(), "must be AddP");
4065   //
4066   // AddP cases for Base and Address inputs:
4067   // case #1. Direct object's field reference:
4068   //     Allocate
4069   //       |
4070   //     Proj #5 ( oop result )
4071   //       |
4072   //     CheckCastPP (cast to instance type)
4073   //      | |
4074   //     AddP  ( base == address )
4075   //
4076   // case #2. Indirect object's field reference:
4077   //      Phi
4078   //       |
4079   //     CastPP (cast to instance type)
4080   //      | |
4081   //     AddP  ( base == address )
4082   //
4083   // case #3. Raw object's field reference for Initialize node.
4084   //          Could have an additional Phi merging multiple allocations.
4085   //      Allocate
4086   //        |
4087   //      Proj #5 ( oop result )
4088   //  top   |
4089   //     \  |
4090   //     AddP  ( base == top )
4091   //
4092   // case #4. Array's element reference:
4093   //   {CheckCastPP | CastPP}
4094   //     |  | |
4095   //     |  AddP ( array's element offset )
4096   //     |  |
4097   //     AddP ( array's offset )
4098   //
4099   // case #5. Raw object's field reference for arraycopy stub call:
4100   //          The inline_native_clone() case when the arraycopy stub is called
4101   //          after the allocation before Initialize and CheckCastPP nodes.
4102   //      Allocate
4103   //        |
4104   //      Proj #5 ( oop result )
4105   //       | |
4106   //       AddP  ( base == address )
4107   //
4108   // case #6. Constant Pool, ThreadLocal, CastX2P, Klass, OSR buffer buf or
4109   //          Raw object's field reference:
4110   //      {ConP, ThreadLocal, CastX2P, raw Load, Parm0}
4111   //  top   |
4112   //     \  |
4113   //     AddP  ( base == top )
4114   //
4115   // case #7. Klass's field reference.
4116   //      LoadKlass
4117   //       | |
4118   //       AddP  ( base == address )
4119   //
4120   // case #8. narrow Klass's field reference.
4121   //      LoadNKlass
4122   //       |
4123   //      DecodeN
4124   //       | |
4125   //       AddP  ( base == address )
4126   //
4127   // case #9. Mixed unsafe access
4128   //    {instance}
4129   //        |
4130   //      CheckCastPP (raw)
4131   //  top   |
4132   //     \  |
4133   //     AddP  ( base == top )
4134   //
4135   // case #10. Klass fetched with
4136   //           LibraryCallKit::load_*_refined_array_klass()
4137   //           which has en extra Phi.
4138   //  LoadKlass   LoadKlass
4139   //       |          |
4140   //     CastPP    CastPP
4141   //          \   /
4142   //           Phi
4143   //      top   |
4144   //         \  |
4145   //         AddP  ( base == top )
4146   //
4147   Node *base = addp->in(AddPNode::Base);
4148   if (base->uncast()->is_top()) { // The AddP case #3, #6, #9, and #10.
4149     base = addp->in(AddPNode::Address);
4150     while (base->is_AddP()) {
4151       // Case #6 (unsafe access) may have several chained AddP nodes.
4152       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
4153       base = base->in(AddPNode::Address);
4154     }
4155     if (base->Opcode() == Op_CheckCastPP &&
4156         base->bottom_type()->isa_rawptr() &&
4157         _igvn->type(base->in(1))->isa_oopptr()) {
4158       base = base->in(1); // Case #9
4159     } else {
4160       // Case #3, #6, and #10
4161       Node* uncast_base = base->uncast();
4162       int opcode = uncast_base->Opcode();
4163       assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
4164              opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
4165              (_igvn->C->is_osr_compilation() && uncast_base->is_Parm() && uncast_base->as_Parm()->_con == TypeFunc::Parms)||
4166              (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != nullptr)) ||
4167              (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_klassptr() != nullptr)) ||
4168              is_captured_store_address(addp) ||
4169              is_load_array_klass_related(uncast_base), "sanity");
4170     }
4171   }
4172   return base;
4173 }
4174 
4175 #ifdef ASSERT
4176 // Case #10
4177 bool ConnectionGraph::is_load_array_klass_related(const Node* uncast_base) {
4178   if (!uncast_base->is_Phi() || uncast_base->req() != 3) {
4179     return false;
4180   }
4181   Node* in1 = uncast_base->in(1);
4182   Node* in2 = uncast_base->in(2);
4183   return in1->uncast()->Opcode() == Op_LoadKlass &&
4184          in2->uncast()->Opcode() == Op_LoadKlass;
4185 }
4186 #endif
4187 
4188 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
4189   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
4190   Node* addp2 = addp->raw_out(0);
4191   if (addp->outcnt() == 1 && addp2->is_AddP() &&
4192       addp2->in(AddPNode::Base) == n &&
4193       addp2->in(AddPNode::Address) == addp) {
4194     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
4195     //
4196     // Find array's offset to push it on worklist first and
4197     // as result process an array's element offset first (pushed second)
4198     // to avoid CastPP for the array's offset.
4199     // Otherwise the inserted CastPP (LocalVar) will point to what
4200     // the AddP (Field) points to. Which would be wrong since
4201     // the algorithm expects the CastPP has the same point as
4202     // as AddP's base CheckCastPP (LocalVar).
4203     //
4204     //    ArrayAllocation
4205     //     |
4206     //    CheckCastPP
4207     //     |
4208     //    memProj (from ArrayAllocation CheckCastPP)
4209     //     |  ||
4210     //     |  ||   Int (element index)
4211     //     |  ||    |   ConI (log(element size))
4212     //     |  ||    |   /
4213     //     |  ||   LShift
4214     //     |  ||  /
4215     //     |  AddP (array's element offset)
4216     //     |  |
4217     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
4218     //     | / /
4219     //     AddP (array's offset)
4220     //      |
4221     //     Load/Store (memory operation on array's element)
4222     //
4223     return addp2;
4224   }
4225   return nullptr;
4226 }
4227 
4228 //
4229 // Adjust the type and inputs of an AddP which computes the
4230 // address of a field of an instance
4231 //
4232 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
4233   PhaseGVN* igvn = _igvn;
4234   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
4235   assert(base_t != nullptr && base_t->is_known_instance(), "expecting instance oopptr");
4236   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
4237   if (t == nullptr) {
4238     // We are computing a raw address for a store captured by an Initialize
4239     // compute an appropriate address type (cases #3 and #5).
4240     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
4241     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
4242     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
4243     assert(offs != Type::OffsetBot, "offset must be a constant");
4244     if (base_t->isa_aryptr() != nullptr) {
4245       // In the case of a flat inline type array, each field has its
4246       // own slice so we need to extract the field being accessed from
4247       // the address computation
4248       t = base_t->isa_aryptr()->add_field_offset_and_offset(offs)->is_oopptr();
4249     } else {
4250       t = base_t->add_offset(offs)->is_oopptr();
4251     }
4252   }
4253   int inst_id = base_t->instance_id();
4254   assert(!t->is_known_instance() || t->instance_id() == inst_id,
4255                              "old type must be non-instance or match new type");
4256 
4257   // The type 't' could be subclass of 'base_t'.
4258   // As result t->offset() could be large then base_t's size and it will
4259   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
4260   // constructor verifies correctness of the offset.
4261   //
4262   // It could happened on subclass's branch (from the type profiling
4263   // inlining) which was not eliminated during parsing since the exactness
4264   // of the allocation type was not propagated to the subclass type check.
4265   //
4266   // Or the type 't' could be not related to 'base_t' at all.
4267   // It could happen when CHA type is different from MDO type on a dead path
4268   // (for example, from instanceof check) which is not collapsed during parsing.
4269   //
4270   // Do nothing for such AddP node and don't process its users since
4271   // this code branch will go away.
4272   //
4273   if (!t->is_known_instance() &&
4274       !base_t->maybe_java_subtype_of(t)) {
4275      return false; // bail out
4276   }
4277   const TypePtr* tinst = base_t->add_offset(t->offset());
4278   if (tinst->isa_aryptr() && t->isa_aryptr()) {
4279     // In the case of a flat inline type array, each field has its
4280     // own slice so we need to keep track of the field being accessed.
4281     tinst = tinst->is_aryptr()->with_field_offset(t->is_aryptr()->field_offset().get());
4282     // Keep array properties (not flat/null-free)
4283     tinst = tinst->is_aryptr()->update_properties(t->is_aryptr());
4284     if (tinst == nullptr) {
4285       return false; // Skip dead path with inconsistent properties
4286     }
4287   }
4288 
4289   // Do NOT remove the next line: ensure a new alias index is allocated
4290   // for the instance type. Note: C++ will not remove it since the call
4291   // has side effect.
4292   int alias_idx = _compile->get_alias_index(tinst);
4293   igvn->set_type(addp, tinst);
4294   // record the allocation in the node map
4295   set_map(addp, get_map(base->_idx));
4296   // Set addp's Base and Address to 'base'.
4297   Node *abase = addp->in(AddPNode::Base);
4298   Node *adr   = addp->in(AddPNode::Address);
4299   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
4300       adr->in(0)->_idx == (uint)inst_id) {
4301     // Skip AddP cases #3 and #5.
4302   } else {
4303     assert(!abase->is_top(), "sanity"); // AddP case #3
4304     if (abase != base) {
4305       igvn->hash_delete(addp);
4306       addp->set_req(AddPNode::Base, base);
4307       if (abase == adr) {
4308         addp->set_req(AddPNode::Address, base);
4309       } else {
4310         // AddP case #4 (adr is array's element offset AddP node)
4311 #ifdef ASSERT
4312         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
4313         assert(adr->is_AddP() && atype != nullptr &&
4314                atype->instance_id() == inst_id, "array's element offset should be processed first");
4315 #endif
4316       }
4317       igvn->hash_insert(addp);
4318     }
4319   }
4320   // Put on IGVN worklist since at least addp's type was changed above.
4321   record_for_optimizer(addp);
4322   return true;
4323 }
4324 
4325 //
4326 // Create a new version of orig_phi if necessary. Returns either the newly
4327 // created phi or an existing phi.  Sets create_new to indicate whether a new
4328 // phi was created.  Cache the last newly created phi in the node map.
4329 //
4330 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
4331   Compile *C = _compile;
4332   PhaseGVN* igvn = _igvn;
4333   new_created = false;
4334   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
4335   // nothing to do if orig_phi is bottom memory or matches alias_idx
4336   if (phi_alias_idx == alias_idx) {
4337     return orig_phi;
4338   }
4339   // Have we recently created a Phi for this alias index?
4340   PhiNode *result = get_map_phi(orig_phi->_idx);
4341   if (result != nullptr && C->get_alias_index(result->adr_type()) == alias_idx) {
4342     return result;
4343   }
4344   // Previous check may fail when the same wide memory Phi was split into Phis
4345   // for different memory slices. Search all Phis for this region.
4346   if (result != nullptr) {
4347     Node* region = orig_phi->in(0);
4348     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
4349       Node* phi = region->fast_out(i);
4350       if (phi->is_Phi() &&
4351           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
4352         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
4353         return phi->as_Phi();
4354       }
4355     }
4356   }
4357   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
4358     if (C->do_escape_analysis() == true && !C->failing()) {
4359       // Retry compilation without escape analysis.
4360       // If this is the first failure, the sentinel string will "stick"
4361       // to the Compile object, and the C2Compiler will see it and retry.
4362       C->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4363     }
4364     return nullptr;
4365   }
4366   orig_phi_worklist.append_if_missing(orig_phi);
4367   const TypePtr *atype = C->get_adr_type(alias_idx);
4368   result = PhiNode::make(orig_phi->in(0), nullptr, Type::MEMORY, atype);
4369   C->copy_node_notes_to(result, orig_phi);
4370   igvn->set_type(result, result->bottom_type());
4371   record_for_optimizer(result);
4372   set_map(orig_phi, result);
4373   new_created = true;
4374   return result;
4375 }
4376 
4377 //
4378 // Return a new version of Memory Phi "orig_phi" with the inputs having the
4379 // specified alias index.
4380 //
4381 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *> &orig_phi_worklist, uint rec_depth) {
4382   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
4383   Compile *C = _compile;
4384   PhaseGVN* igvn = _igvn;
4385   bool new_phi_created;
4386   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
4387   if (!new_phi_created) {
4388     return result;
4389   }
4390   GrowableArray<PhiNode *>  phi_list;
4391   GrowableArray<uint>  cur_input;
4392   PhiNode *phi = orig_phi;
4393   uint idx = 1;
4394   bool finished = false;
4395   while(!finished) {
4396     while (idx < phi->req()) {
4397       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist, rec_depth + 1);
4398       if (mem != nullptr && mem->is_Phi()) {
4399         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
4400         if (new_phi_created) {
4401           // found an phi for which we created a new split, push current one on worklist and begin
4402           // processing new one
4403           phi_list.push(phi);
4404           cur_input.push(idx);
4405           phi = mem->as_Phi();
4406           result = newphi;
4407           idx = 1;
4408           continue;
4409         } else {
4410           mem = newphi;
4411         }
4412       }
4413       if (C->failing()) {
4414         return nullptr;
4415       }
4416       result->set_req(idx++, mem);
4417     }
4418 #ifdef ASSERT
4419     // verify that the new Phi has an input for each input of the original
4420     assert( phi->req() == result->req(), "must have same number of inputs.");
4421     assert( result->in(0) != nullptr && result->in(0) == phi->in(0), "regions must match");
4422 #endif
4423     // Check if all new phi's inputs have specified alias index.
4424     // Otherwise use old phi.
4425     for (uint i = 1; i < phi->req(); i++) {
4426       Node* in = result->in(i);
4427       assert((phi->in(i) == nullptr) == (in == nullptr), "inputs must correspond.");
4428     }
4429     // we have finished processing a Phi, see if there are any more to do
4430     finished = (phi_list.length() == 0 );
4431     if (!finished) {
4432       phi = phi_list.pop();
4433       idx = cur_input.pop();
4434       PhiNode *prev_result = get_map_phi(phi->_idx);
4435       prev_result->set_req(idx++, result);
4436       result = prev_result;
4437     }
4438   }
4439   return result;
4440 }
4441 
4442 //
4443 // The next methods are derived from methods in MemNode.
4444 //
4445 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
4446   Node *mem = mmem;
4447   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
4448   // means an array I have not precisely typed yet.  Do not do any
4449   // alias stuff with it any time soon.
4450   if (toop->base() != Type::AnyPtr &&
4451       !(toop->isa_instptr() &&
4452         toop->is_instptr()->instance_klass()->is_java_lang_Object() &&
4453         toop->offset() == Type::OffsetBot)) {
4454     mem = mmem->memory_at(alias_idx);
4455     // Update input if it is progress over what we have now
4456   }
4457   return mem;
4458 }
4459 
4460 //
4461 // Move memory users to their memory slices.
4462 //
4463 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
4464   Compile* C = _compile;
4465   PhaseGVN* igvn = _igvn;
4466   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
4467   assert(tp != nullptr, "ptr type");
4468   int alias_idx = C->get_alias_index(tp);
4469   int general_idx = C->get_general_index(alias_idx);
4470 
4471   // Move users first
4472   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4473     Node* use = n->fast_out(i);
4474     if (use->is_MergeMem()) {
4475       MergeMemNode* mmem = use->as_MergeMem();
4476       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
4477       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
4478         continue; // Nothing to do
4479       }
4480       // Replace previous general reference to mem node.
4481       uint orig_uniq = C->unique();
4482       Node* m = find_inst_mem(n, general_idx, orig_phis);
4483       assert(orig_uniq == C->unique(), "no new nodes");
4484       mmem->set_memory_at(general_idx, m);
4485       --imax;
4486       --i;
4487     } else if (use->is_MemBar()) {
4488       assert(!use->is_Initialize(), "initializing stores should not be moved");
4489       if (use->req() > MemBarNode::Precedent &&
4490           use->in(MemBarNode::Precedent) == n) {
4491         // Don't move related membars.
4492         record_for_optimizer(use);
4493         continue;
4494       }
4495       tp = use->as_MemBar()->adr_type()->isa_ptr();
4496       if ((tp != nullptr && C->get_alias_index(tp) == alias_idx) ||
4497           alias_idx == general_idx) {
4498         continue; // Nothing to do
4499       }
4500       // Move to general memory slice.
4501       uint orig_uniq = C->unique();
4502       Node* m = find_inst_mem(n, general_idx, orig_phis);
4503       assert(orig_uniq == C->unique(), "no new nodes");
4504       igvn->hash_delete(use);
4505       imax -= use->replace_edge(n, m, igvn);
4506       igvn->hash_insert(use);
4507       record_for_optimizer(use);
4508       --i;
4509 #ifdef ASSERT
4510     } else if (use->is_Mem()) {
4511       // Memory nodes should have new memory input.
4512       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
4513       assert(tp != nullptr, "ptr type");
4514       int idx = C->get_alias_index(tp);
4515       assert(get_map(use->_idx) != nullptr || idx == alias_idx,
4516              "Following memory nodes should have new memory input or be on the same memory slice");
4517     } else if (use->is_Phi()) {
4518       // Phi nodes should be split and moved already.
4519       tp = use->as_Phi()->adr_type()->isa_ptr();
4520       assert(tp != nullptr, "ptr type");
4521       int idx = C->get_alias_index(tp);
4522       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
4523     } else {
4524       use->dump();
4525       assert(false, "should not be here");
4526 #endif
4527     }
4528   }
4529 }
4530 
4531 //
4532 // Search memory chain of "mem" to find a MemNode whose address
4533 // is the specified alias index.
4534 //
4535 #define FIND_INST_MEM_RECURSION_DEPTH_LIMIT 1000
4536 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis, uint rec_depth) {
4537   if (rec_depth > FIND_INST_MEM_RECURSION_DEPTH_LIMIT) {
4538     _compile->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4539     return nullptr;
4540   }
4541   if (orig_mem == nullptr) {
4542     return orig_mem;
4543   }
4544   Compile* C = _compile;
4545   PhaseGVN* igvn = _igvn;
4546   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
4547   bool is_instance = (toop != nullptr) && toop->is_known_instance();
4548   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
4549   Node *prev = nullptr;
4550   Node *result = orig_mem;
4551   while (prev != result) {
4552     prev = result;
4553     if (result == start_mem) {
4554       break;  // hit one of our sentinels
4555     }
4556     if (result->is_Mem()) {
4557       const Type *at = igvn->type(result->in(MemNode::Address));
4558       if (at == Type::TOP) {
4559         break; // Dead
4560       }
4561       assert (at->isa_ptr() != nullptr, "pointer type required.");
4562       int idx = C->get_alias_index(at->is_ptr());
4563       if (idx == alias_idx) {
4564         break; // Found
4565       }
4566       if (!is_instance && (at->isa_oopptr() == nullptr ||
4567                            !at->is_oopptr()->is_known_instance())) {
4568         break; // Do not skip store to general memory slice.
4569       }
4570       result = result->in(MemNode::Memory);
4571     }
4572     if (!is_instance) {
4573       continue;  // don't search further for non-instance types
4574     }
4575     // skip over a call which does not affect this memory slice
4576     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
4577       Node *proj_in = result->in(0);
4578       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
4579         break;  // hit one of our sentinels
4580       } else if (proj_in->is_Call()) {
4581         // ArrayCopy node processed here as well
4582         CallNode *call = proj_in->as_Call();
4583         if (!call->may_modify(toop, igvn)) {
4584           result = call->in(TypeFunc::Memory);
4585         }
4586       } else if (proj_in->is_Initialize()) {
4587         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
4588         // Stop if this is the initialization for the object instance which
4589         // which contains this memory slice, otherwise skip over it.
4590         if (alloc == nullptr || alloc->_idx != (uint)toop->instance_id()) {
4591           result = proj_in->in(TypeFunc::Memory);
4592         } else if (C->get_alias_index(result->adr_type()) != alias_idx) {
4593           assert(C->get_general_index(alias_idx) == C->get_alias_index(result->adr_type()), "should be projection for the same field/array element");
4594           result = get_map(result->_idx);
4595           assert(result != nullptr, "new projection should have been allocated");
4596           break;
4597         }
4598       } else if (proj_in->is_MemBar()) {
4599         // Check if there is an array copy for a clone
4600         // Step over GC barrier when ReduceInitialCardMarks is disabled
4601         BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
4602         Node* control_proj_ac = bs->step_over_gc_barrier(proj_in->in(0));
4603 
4604         if (control_proj_ac->is_Proj() && control_proj_ac->in(0)->is_ArrayCopy()) {
4605           // Stop if it is a clone
4606           ArrayCopyNode* ac = control_proj_ac->in(0)->as_ArrayCopy();
4607           if (ac->may_modify(toop, igvn)) {
4608             break;
4609           }
4610         }
4611         result = proj_in->in(TypeFunc::Memory);
4612       }
4613     } else if (result->is_MergeMem()) {
4614       MergeMemNode *mmem = result->as_MergeMem();
4615       result = step_through_mergemem(mmem, alias_idx, toop);
4616       if (result == mmem->base_memory()) {
4617         // Didn't find instance memory, search through general slice recursively.
4618         result = mmem->memory_at(C->get_general_index(alias_idx));
4619         result = find_inst_mem(result, alias_idx, orig_phis, rec_depth + 1);
4620         if (C->failing()) {
4621           return nullptr;
4622         }
4623         mmem->set_memory_at(alias_idx, result);
4624       }
4625     } else if (result->is_Phi() &&
4626                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
4627       Node *un = result->as_Phi()->unique_input(igvn);
4628       if (un != nullptr) {
4629         orig_phis.append_if_missing(result->as_Phi());
4630         result = un;
4631       } else {
4632         break;
4633       }
4634     } else if (result->is_ClearArray()) {
4635       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
4636         // Can not bypass initialization of the instance
4637         // we are looking for.
4638         break;
4639       }
4640       // Otherwise skip it (the call updated 'result' value).
4641     } else if (result->Opcode() == Op_SCMemProj) {
4642       Node* mem = result->in(0);
4643       Node* adr = nullptr;
4644       if (mem->is_LoadStore()) {
4645         adr = mem->in(MemNode::Address);
4646       } else {
4647         assert(mem->Opcode() == Op_EncodeISOArray ||
4648                mem->Opcode() == Op_StrCompressedCopy, "sanity");
4649         adr = mem->in(3); // Memory edge corresponds to destination array
4650       }
4651       const Type *at = igvn->type(adr);
4652       if (at != Type::TOP) {
4653         assert(at->isa_ptr() != nullptr, "pointer type required.");
4654         int idx = C->get_alias_index(at->is_ptr());
4655         if (idx == alias_idx) {
4656           // Assert in debug mode
4657           assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
4658           break; // In product mode return SCMemProj node
4659         }
4660       }
4661       result = mem->in(MemNode::Memory);
4662     } else if (result->Opcode() == Op_StrInflatedCopy) {
4663       Node* adr = result->in(3); // Memory edge corresponds to destination array
4664       const Type *at = igvn->type(adr);
4665       if (at != Type::TOP) {
4666         assert(at->isa_ptr() != nullptr, "pointer type required.");
4667         int idx = C->get_alias_index(at->is_ptr());
4668         if (idx == alias_idx) {
4669           // Assert in debug mode
4670           assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
4671           break; // In product mode return SCMemProj node
4672         }
4673       }
4674       result = result->in(MemNode::Memory);
4675     }
4676   }
4677   if (result->is_Phi()) {
4678     PhiNode *mphi = result->as_Phi();
4679     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
4680     const TypePtr *t = mphi->adr_type();
4681     if (!is_instance) {
4682       // Push all non-instance Phis on the orig_phis worklist to update inputs
4683       // during Phase 4 if needed.
4684       orig_phis.append_if_missing(mphi);
4685     } else if (C->get_alias_index(t) != alias_idx) {
4686       // Create a new Phi with the specified alias index type.
4687       result = split_memory_phi(mphi, alias_idx, orig_phis, rec_depth + 1);
4688     }
4689   }
4690   // the result is either MemNode, PhiNode, InitializeNode.
4691   return result;
4692 }
4693 
4694 //
4695 //  Convert the types of non-escaped object to instance types where possible,
4696 //  propagate the new type information through the graph, and update memory
4697 //  edges and MergeMem inputs to reflect the new type.
4698 //
4699 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
4700 //  The processing is done in 4 phases:
4701 //
4702 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
4703 //            types for the CheckCastPP for allocations where possible.
4704 //            Propagate the new types through users as follows:
4705 //               casts and Phi:  push users on alloc_worklist
4706 //               AddP:  cast Base and Address inputs to the instance type
4707 //                      push any AddP users on alloc_worklist and push any memnode
4708 //                      users onto memnode_worklist.
4709 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
4710 //            search the Memory chain for a store with the appropriate type
4711 //            address type.  If a Phi is found, create a new version with
4712 //            the appropriate memory slices from each of the Phi inputs.
4713 //            For stores, process the users as follows:
4714 //               MemNode:  push on memnode_worklist
4715 //               MergeMem: push on mergemem_worklist
4716 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
4717 //            moving the first node encountered of each  instance type to the
4718 //            the input corresponding to its alias index.
4719 //            appropriate memory slice.
4720 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
4721 //
4722 // In the following example, the CheckCastPP nodes are the cast of allocation
4723 // results and the allocation of node 29 is non-escaped and eligible to be an
4724 // instance type.
4725 //
4726 // We start with:
4727 //
4728 //     7 Parm #memory
4729 //    10  ConI  "12"
4730 //    19  CheckCastPP   "Foo"
4731 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
4732 //    29  CheckCastPP   "Foo"
4733 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
4734 //
4735 //    40  StoreP  25   7  20   ... alias_index=4
4736 //    50  StoreP  35  40  30   ... alias_index=4
4737 //    60  StoreP  45  50  20   ... alias_index=4
4738 //    70  LoadP    _  60  30   ... alias_index=4
4739 //    80  Phi     75  50  60   Memory alias_index=4
4740 //    90  LoadP    _  80  30   ... alias_index=4
4741 //   100  LoadP    _  80  20   ... alias_index=4
4742 //
4743 //
4744 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
4745 // and creating a new alias index for node 30.  This gives:
4746 //
4747 //     7 Parm #memory
4748 //    10  ConI  "12"
4749 //    19  CheckCastPP   "Foo"
4750 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
4751 //    29  CheckCastPP   "Foo"  iid=24
4752 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
4753 //
4754 //    40  StoreP  25   7  20   ... alias_index=4
4755 //    50  StoreP  35  40  30   ... alias_index=6
4756 //    60  StoreP  45  50  20   ... alias_index=4
4757 //    70  LoadP    _  60  30   ... alias_index=6
4758 //    80  Phi     75  50  60   Memory alias_index=4
4759 //    90  LoadP    _  80  30   ... alias_index=6
4760 //   100  LoadP    _  80  20   ... alias_index=4
4761 //
4762 // In phase 2, new memory inputs are computed for the loads and stores,
4763 // And a new version of the phi is created.  In phase 4, the inputs to
4764 // node 80 are updated and then the memory nodes are updated with the
4765 // values computed in phase 2.  This results in:
4766 //
4767 //     7 Parm #memory
4768 //    10  ConI  "12"
4769 //    19  CheckCastPP   "Foo"
4770 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
4771 //    29  CheckCastPP   "Foo"  iid=24
4772 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
4773 //
4774 //    40  StoreP  25  7   20   ... alias_index=4
4775 //    50  StoreP  35  7   30   ... alias_index=6
4776 //    60  StoreP  45  40  20   ... alias_index=4
4777 //    70  LoadP    _  50  30   ... alias_index=6
4778 //    80  Phi     75  40  60   Memory alias_index=4
4779 //   120  Phi     75  50  50   Memory alias_index=6
4780 //    90  LoadP    _ 120  30   ... alias_index=6
4781 //   100  LoadP    _  80  20   ... alias_index=4
4782 //
4783 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist,
4784                                          GrowableArray<ArrayCopyNode*> &arraycopy_worklist,
4785                                          GrowableArray<MergeMemNode*> &mergemem_worklist,
4786                                          Unique_Node_List &reducible_merges) {
4787   DEBUG_ONLY(Unique_Node_List reduced_merges;)
4788   GrowableArray<Node *>  memnode_worklist;
4789   GrowableArray<PhiNode *>  orig_phis;
4790   PhaseIterGVN  *igvn = _igvn;
4791   uint new_index_start = (uint) _compile->num_alias_types();
4792   VectorSet visited;
4793   ideal_nodes.clear(); // Reset for use with set_map/get_map.
4794 
4795   //  Phase 1:  Process possible allocations from alloc_worklist.
4796   //  Create instance types for the CheckCastPP for allocations where possible.
4797   //
4798   // (Note: don't forget to change the order of the second AddP node on
4799   //  the alloc_worklist if the order of the worklist processing is changed,
4800   //  see the comment in find_second_addp().)
4801   //
4802   while (alloc_worklist.length() != 0) {
4803     Node *n = alloc_worklist.pop();
4804     uint ni = n->_idx;
4805     if (n->is_Call()) {
4806       CallNode *alloc = n->as_Call();
4807       // copy escape information to call node
4808       PointsToNode* ptn = ptnode_adr(alloc->_idx);
4809       PointsToNode::EscapeState es = ptn->escape_state();
4810       // We have an allocation or call which returns a Java object,
4811       // see if it is non-escaped.
4812       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable()) {
4813         continue;
4814       }
4815       // Find CheckCastPP for the allocate or for the return value of a call
4816       n = alloc->result_cast();
4817       if (n == nullptr) {            // No uses except Initialize node
4818         if (alloc->is_Allocate()) {
4819           // Set the scalar_replaceable flag for allocation
4820           // so it could be eliminated if it has no uses.
4821           alloc->as_Allocate()->_is_scalar_replaceable = true;
4822         }
4823         continue;
4824       }
4825       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
4826         // we could reach here for allocate case if one init is associated with many allocs.
4827         if (alloc->is_Allocate()) {
4828           alloc->as_Allocate()->_is_scalar_replaceable = false;
4829         }
4830         continue;
4831       }
4832 
4833       // The inline code for Object.clone() casts the allocation result to
4834       // java.lang.Object and then to the actual type of the allocated
4835       // object. Detect this case and use the second cast.
4836       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
4837       // the allocation result is cast to java.lang.Object and then
4838       // to the actual Array type.
4839       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
4840           && (alloc->is_AllocateArray() ||
4841               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeInstKlassPtr::OBJECT)) {
4842         Node *cast2 = nullptr;
4843         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
4844           Node *use = n->fast_out(i);
4845           if (use->is_CheckCastPP()) {
4846             cast2 = use;
4847             break;
4848           }
4849         }
4850         if (cast2 != nullptr) {
4851           n = cast2;
4852         } else {
4853           // Non-scalar replaceable if the allocation type is unknown statically
4854           // (reflection allocation), the object can't be restored during
4855           // deoptimization without precise type.
4856           continue;
4857         }
4858       }
4859 
4860       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
4861       if (t == nullptr) {
4862         continue;  // not a TypeOopPtr
4863       }
4864       if (!t->klass_is_exact()) {
4865         continue; // not an unique type
4866       }
4867       if (alloc->is_Allocate()) {
4868         // Set the scalar_replaceable flag for allocation
4869         // so it could be eliminated.
4870         alloc->as_Allocate()->_is_scalar_replaceable = true;
4871       }
4872       set_escape_state(ptnode_adr(n->_idx), es NOT_PRODUCT(COMMA trace_propagate_message(ptn))); // CheckCastPP escape state
4873       // in order for an object to be scalar-replaceable, it must be:
4874       //   - a direct allocation (not a call returning an object)
4875       //   - non-escaping
4876       //   - eligible to be a unique type
4877       //   - not determined to be ineligible by escape analysis
4878       set_map(alloc, n);
4879       set_map(n, alloc);
4880       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
4881       igvn->hash_delete(n);
4882       igvn->set_type(n,  tinst);
4883       n->raise_bottom_type(tinst);
4884       igvn->hash_insert(n);
4885       record_for_optimizer(n);
4886       // Allocate an alias index for the header fields. Accesses to
4887       // the header emitted during macro expansion wouldn't have
4888       // correct memory state otherwise.
4889       _compile->get_alias_index(tinst->add_offset(oopDesc::mark_offset_in_bytes()));
4890       _compile->get_alias_index(tinst->add_offset(oopDesc::klass_offset_in_bytes()));
4891       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
4892         // Add a new NarrowMem projection for each existing NarrowMem projection with new adr type
4893         InitializeNode* init = alloc->as_Allocate()->initialization();
4894         assert(init != nullptr, "can't find Initialization node for this Allocate node");
4895         auto process_narrow_proj = [&](NarrowMemProjNode* proj) {
4896           const TypePtr* adr_type = proj->adr_type();
4897           const TypePtr* new_adr_type = tinst->with_offset(adr_type->offset());
4898           if (adr_type->isa_aryptr()) {
4899             // In the case of a flat inline type array, each field has its own slice so we need a
4900             // NarrowMemProj for each field of the flat array elements
4901             new_adr_type = new_adr_type->is_aryptr()->with_field_offset(adr_type->is_aryptr()->field_offset().get());
4902           }
4903           if (adr_type != new_adr_type && !init->already_has_narrow_mem_proj_with_adr_type(new_adr_type)) {
4904             DEBUG_ONLY( uint alias_idx = _compile->get_alias_index(new_adr_type); )
4905             assert(_compile->get_general_index(alias_idx) == _compile->get_alias_index(adr_type), "new adr type should be narrowed down from existing adr type");
4906             NarrowMemProjNode* new_proj = new NarrowMemProjNode(init, new_adr_type);
4907             igvn->set_type(new_proj, new_proj->bottom_type());
4908             record_for_optimizer(new_proj);
4909             set_map(proj, new_proj); // record it so ConnectionGraph::find_inst_mem() can find it
4910           }
4911         };
4912         init->for_each_narrow_mem_proj_with_new_uses(process_narrow_proj);
4913 
4914         // First, put on the worklist all Field edges from Connection Graph
4915         // which is more accurate than putting immediate users from Ideal Graph.
4916         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
4917           PointsToNode* tgt = e.get();
4918           if (tgt->is_Arraycopy()) {
4919             continue;
4920           }
4921           Node* use = tgt->ideal_node();
4922           assert(tgt->is_Field() && use->is_AddP(),
4923                  "only AddP nodes are Field edges in CG");
4924           if (use->outcnt() > 0) { // Don't process dead nodes
4925             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
4926             if (addp2 != nullptr) {
4927               assert(alloc->is_AllocateArray(),"array allocation was expected");
4928               alloc_worklist.append_if_missing(addp2);
4929             }
4930             alloc_worklist.append_if_missing(use);
4931           }
4932         }
4933 
4934         // An allocation may have an Initialize which has raw stores. Scan
4935         // the users of the raw allocation result and push AddP users
4936         // on alloc_worklist.
4937         Node *raw_result = alloc->proj_out_or_null(TypeFunc::Parms);
4938         assert (raw_result != nullptr, "must have an allocation result");
4939         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
4940           Node *use = raw_result->fast_out(i);
4941           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
4942             Node* addp2 = find_second_addp(use, raw_result);
4943             if (addp2 != nullptr) {
4944               assert(alloc->is_AllocateArray(),"array allocation was expected");
4945               alloc_worklist.append_if_missing(addp2);
4946             }
4947             alloc_worklist.append_if_missing(use);
4948           } else if (use->is_MemBar()) {
4949             memnode_worklist.append_if_missing(use);
4950           }
4951         }
4952       }
4953     } else if (n->is_AddP()) {
4954       if (has_reducible_merge_base(n->as_AddP(), reducible_merges)) {
4955         // This AddP will go away when we reduce the Phi
4956         continue;
4957       }
4958       Node* addp_base = get_addp_base(n);
4959       JavaObjectNode* jobj = unique_java_object(addp_base);
4960       if (jobj == nullptr || jobj == phantom_obj) {
4961 #ifdef ASSERT
4962         ptnode_adr(get_addp_base(n)->_idx)->dump();
4963         ptnode_adr(n->_idx)->dump();
4964         assert(jobj != nullptr && jobj != phantom_obj, "escaped allocation");
4965 #endif
4966         _compile->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
4967         return;
4968       }
4969       Node *base = get_map(jobj->idx());  // CheckCastPP node
4970       if (!split_AddP(n, base)) continue; // wrong type from dead path
4971     } else if (n->is_Phi() ||
4972                n->is_CheckCastPP() ||
4973                n->is_EncodeP() ||
4974                n->is_DecodeN() ||
4975                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
4976       if (visited.test_set(n->_idx)) {
4977         assert(n->is_Phi(), "loops only through Phi's");
4978         continue;  // already processed
4979       }
4980       // Reducible Phi's will be removed from the graph after split_unique_types
4981       // finishes. For now we just try to split out the SR inputs of the merge.
4982       Node* parent = n->in(1);
4983       if (reducible_merges.member(n)) {
4984         reduce_phi(n->as_Phi(), alloc_worklist);
4985 #ifdef ASSERT
4986         if (VerifyReduceAllocationMerges) {
4987           reduced_merges.push(n);
4988         }
4989 #endif
4990         continue;
4991       } else if (reducible_merges.member(parent)) {
4992         // 'n' is an user of a reducible merge (a Phi). It will be simplified as
4993         // part of reduce_merge.
4994         continue;
4995       }
4996       JavaObjectNode* jobj = unique_java_object(n);
4997       if (jobj == nullptr || jobj == phantom_obj) {
4998 #ifdef ASSERT
4999         ptnode_adr(n->_idx)->dump();
5000         assert(jobj != nullptr && jobj != phantom_obj, "escaped allocation");
5001 #endif
5002         _compile->record_failure(_invocation > 0 ? C2Compiler::retry_no_iterative_escape_analysis() : C2Compiler::retry_no_escape_analysis());
5003         return;
5004       } else {
5005         Node *val = get_map(jobj->idx());   // CheckCastPP node
5006         TypeNode *tn = n->as_Type();
5007         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
5008         assert(tinst != nullptr && tinst->is_known_instance() &&
5009                tinst->instance_id() == jobj->idx() , "instance type expected.");
5010 
5011         const Type *tn_type = igvn->type(tn);
5012         const TypeOopPtr *tn_t;
5013         if (tn_type->isa_narrowoop()) {
5014           tn_t = tn_type->make_ptr()->isa_oopptr();
5015         } else {
5016           tn_t = tn_type->isa_oopptr();
5017         }
5018         if (tn_t != nullptr && tinst->maybe_java_subtype_of(tn_t)) {
5019           if (tn_t->isa_aryptr()) {
5020             // Keep array properties (not flat/null-free)
5021             tinst = tinst->is_aryptr()->update_properties(tn_t->is_aryptr());
5022             if (tinst == nullptr) {
5023               continue; // Skip dead path with inconsistent properties
5024             }
5025           }
5026           if (tn_type->isa_narrowoop()) {
5027             tn_type = tinst->make_narrowoop();
5028           } else {
5029             tn_type = tinst;
5030           }
5031           igvn->hash_delete(tn);
5032           igvn->set_type(tn, tn_type);
5033           tn->set_type(tn_type);
5034           igvn->hash_insert(tn);
5035           record_for_optimizer(n);
5036         } else {
5037           assert(tn_type == TypePtr::NULL_PTR ||
5038                  (tn_t != nullptr && !tinst->maybe_java_subtype_of(tn_t)),
5039                  "unexpected type");
5040           continue; // Skip dead path with different type
5041         }
5042       }
5043     } else {
5044       DEBUG_ONLY(n->dump();)
5045       assert(false, "EA: unexpected node");
5046       continue;
5047     }
5048     // push allocation's users on appropriate worklist
5049     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
5050       Node *use = n->fast_out(i);
5051       if (use->is_Mem() && use->in(MemNode::Address) == n) {
5052         // Load/store to instance's field
5053         memnode_worklist.append_if_missing(use);
5054       } else if (use->is_MemBar()) {
5055         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
5056           memnode_worklist.append_if_missing(use);
5057         }
5058       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
5059         Node* addp2 = find_second_addp(use, n);
5060         if (addp2 != nullptr) {
5061           alloc_worklist.append_if_missing(addp2);
5062         }
5063         alloc_worklist.append_if_missing(use);
5064       } else if (use->is_Phi() ||
5065                  use->is_CheckCastPP() ||
5066                  use->is_EncodeNarrowPtr() ||
5067                  use->is_DecodeNarrowPtr() ||
5068                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
5069         alloc_worklist.append_if_missing(use);
5070 #ifdef ASSERT
5071       } else if (use->is_Mem()) {
5072         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
5073       } else if (use->is_MergeMem()) {
5074         assert(mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
5075       } else if (use->is_SafePoint()) {
5076         // Look for MergeMem nodes for calls which reference unique allocation
5077         // (through CheckCastPP nodes) even for debug info.
5078         Node* m = use->in(TypeFunc::Memory);
5079         if (m->is_MergeMem()) {
5080           assert(mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
5081         }
5082       } else if (use->Opcode() == Op_EncodeISOArray) {
5083         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
5084           // EncodeISOArray overwrites destination array
5085           memnode_worklist.append_if_missing(use);
5086         }
5087       } else if (use->Opcode() == Op_Return) {
5088         // Allocation is referenced by field of returned inline type
5089         assert(_compile->tf()->returns_inline_type_as_fields(), "EA: unexpected reference by ReturnNode");
5090       } else {
5091         uint op = use->Opcode();
5092         if ((op == Op_StrCompressedCopy || op == Op_StrInflatedCopy) &&
5093             (use->in(MemNode::Memory) == n)) {
5094           // They overwrite memory edge corresponding to destination array,
5095           memnode_worklist.append_if_missing(use);
5096         } else if (!(op == Op_CmpP || op == Op_Conv2B ||
5097               op == Op_CastP2X ||
5098               op == Op_FastLock || op == Op_AryEq ||
5099               op == Op_StrComp || op == Op_CountPositives ||
5100               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
5101               op == Op_StrEquals || op == Op_VectorizedHashCode ||
5102               op == Op_StrIndexOf || op == Op_StrIndexOfChar ||
5103               op == Op_SubTypeCheck || op == Op_InlineType || op == Op_FlatArrayCheck ||
5104               op == Op_ReinterpretS2HF ||
5105               op == Op_ReachabilityFence ||
5106               BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(use))) {
5107           n->dump();
5108           use->dump();
5109           assert(false, "EA: missing allocation reference path");
5110         }
5111 #endif
5112       }
5113     }
5114 
5115   }
5116 
5117 #ifdef ASSERT
5118   if (VerifyReduceAllocationMerges) {
5119     for (uint i = 0; i < reducible_merges.size(); i++) {
5120       Node* phi = reducible_merges.at(i);
5121 
5122       if (!reduced_merges.member(phi)) {
5123         phi->dump(2);
5124         phi->dump(-2);
5125         assert(false, "This reducible merge wasn't reduced.");
5126       }
5127 
5128       // At this point reducible Phis shouldn't have AddP users anymore; only SafePoints or Casts.
5129       for (DUIterator_Fast jmax, j = phi->fast_outs(jmax); j < jmax; j++) {
5130         Node* use = phi->fast_out(j);
5131         if (!use->is_SafePoint() && !use->is_CastPP()) {
5132           phi->dump(2);
5133           phi->dump(-2);
5134           assert(false, "Unexpected user of reducible Phi -> %d:%s:%d", use->_idx, use->Name(), use->outcnt());
5135         }
5136       }
5137     }
5138   }
5139 #endif
5140 
5141   // Go over all ArrayCopy nodes and if one of the inputs has a unique
5142   // type, record it in the ArrayCopy node so we know what memory this
5143   // node uses/modified.
5144   for (int next = 0; next < arraycopy_worklist.length(); next++) {
5145     ArrayCopyNode* ac = arraycopy_worklist.at(next);
5146     Node* dest = ac->in(ArrayCopyNode::Dest);
5147     if (dest->is_AddP()) {
5148       dest = get_addp_base(dest);
5149     }
5150     JavaObjectNode* jobj = unique_java_object(dest);
5151     if (jobj != nullptr) {
5152       Node *base = get_map(jobj->idx());
5153       if (base != nullptr) {
5154         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
5155         ac->_dest_type = base_t;
5156       }
5157     }
5158     Node* src = ac->in(ArrayCopyNode::Src);
5159     if (src->is_AddP()) {
5160       src = get_addp_base(src);
5161     }
5162     jobj = unique_java_object(src);
5163     if (jobj != nullptr) {
5164       Node* base = get_map(jobj->idx());
5165       if (base != nullptr) {
5166         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
5167         ac->_src_type = base_t;
5168       }
5169     }
5170   }
5171 
5172   // New alias types were created in split_AddP().
5173   uint new_index_end = (uint) _compile->num_alias_types();
5174 
5175   _compile->print_method(PHASE_EA_AFTER_SPLIT_UNIQUE_TYPES_1, 5);
5176 
5177   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
5178   //            compute new values for Memory inputs  (the Memory inputs are not
5179   //            actually updated until phase 4.)
5180   if (memnode_worklist.length() == 0)
5181     return;  // nothing to do
5182   while (memnode_worklist.length() != 0) {
5183     Node *n = memnode_worklist.pop();
5184     if (visited.test_set(n->_idx)) {
5185       continue;
5186     }
5187     if (n->is_Phi() || n->is_ClearArray()) {
5188       // we don't need to do anything, but the users must be pushed
5189     } else if (n->is_MemBar()) { // MemBar nodes
5190       if (!n->is_Initialize()) { // memory projections for Initialize pushed below (so we get to all their uses)
5191         // we don't need to do anything, but the users must be pushed
5192         n = n->as_MemBar()->proj_out_or_null(TypeFunc::Memory);
5193         if (n == nullptr) {
5194           continue;
5195         }
5196       }
5197     } else if (n->is_CallLeaf()) {
5198       // Runtime calls with narrow memory input (no MergeMem node)
5199       // get the memory projection
5200       n = n->as_Call()->proj_out_or_null(TypeFunc::Memory);
5201       if (n == nullptr) {
5202         continue;
5203       }
5204     } else if (n->Opcode() == Op_StrInflatedCopy) {
5205       // Check direct uses of StrInflatedCopy.
5206       // It is memory type Node - no special SCMemProj node.
5207     } else if (n->Opcode() == Op_StrCompressedCopy ||
5208                n->Opcode() == Op_EncodeISOArray) {
5209       // get the memory projection
5210       n = n->find_out_with(Op_SCMemProj);
5211       assert(n != nullptr && n->Opcode() == Op_SCMemProj, "memory projection required");
5212     } else if (n->is_CallLeaf() && n->as_CallLeaf()->_name != nullptr &&
5213                strcmp(n->as_CallLeaf()->_name, "store_unknown_inline") == 0) {
5214       n = n->as_CallLeaf()->proj_out(TypeFunc::Memory);
5215     } else if (n->is_Proj()) {
5216       assert(n->in(0)->is_Initialize(), "we only push memory projections for Initialize");
5217     } else {
5218 #ifdef ASSERT
5219       if (!n->is_Mem()) {
5220         n->dump();
5221       }
5222       assert(n->is_Mem(), "memory node required.");
5223 #endif
5224       Node *addr = n->in(MemNode::Address);
5225       const Type *addr_t = igvn->type(addr);
5226       if (addr_t == Type::TOP) {
5227         continue;
5228       }
5229       assert (addr_t->isa_ptr() != nullptr, "pointer type required.");
5230       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
5231       assert ((uint)alias_idx < new_index_end, "wrong alias index");
5232       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
5233       if (_compile->failing()) {
5234         return;
5235       }
5236       if (mem != n->in(MemNode::Memory)) {
5237         // We delay the memory edge update since we need old one in
5238         // MergeMem code below when instances memory slices are separated.
5239         set_map(n, mem);
5240       }
5241       if (n->is_Load()) {
5242         continue;  // don't push users
5243       } else if (n->is_LoadStore()) {
5244         // get the memory projection
5245         n = n->find_out_with(Op_SCMemProj);
5246         assert(n != nullptr && n->Opcode() == Op_SCMemProj, "memory projection required");
5247       }
5248     }
5249     // push user on appropriate worklist
5250     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
5251       Node *use = n->fast_out(i);
5252       if (use->is_Phi() || use->is_ClearArray()) {
5253         memnode_worklist.append_if_missing(use);
5254       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
5255         memnode_worklist.append_if_missing(use);
5256       } else if (use->is_MemBar() || use->is_CallLeaf()) {
5257         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
5258           memnode_worklist.append_if_missing(use);
5259         }
5260       } else if (use->is_Proj()) {
5261         assert(n->is_Initialize(), "We only push projections of Initialize");
5262         if (use->as_Proj()->_con == TypeFunc::Memory) { // Ignore precedent edge
5263           memnode_worklist.append_if_missing(use);
5264         }
5265 #ifdef ASSERT
5266       } else if (use->is_Mem()) {
5267         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
5268       } else if (use->is_MergeMem()) {
5269         assert(mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
5270       } else if (use->Opcode() == Op_EncodeISOArray) {
5271         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
5272           // EncodeISOArray overwrites destination array
5273           memnode_worklist.append_if_missing(use);
5274         }
5275       } else if (use->is_CallLeaf() && use->as_CallLeaf()->_name != nullptr &&
5276                  strcmp(use->as_CallLeaf()->_name, "store_unknown_inline") == 0) {
5277         // store_unknown_inline overwrites destination array
5278         memnode_worklist.append_if_missing(use);
5279       } else {
5280         uint op = use->Opcode();
5281         if ((use->in(MemNode::Memory) == n) &&
5282             (op == Op_StrCompressedCopy || op == Op_StrInflatedCopy)) {
5283           // They overwrite memory edge corresponding to destination array,
5284           memnode_worklist.append_if_missing(use);
5285         } else if (!(BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(use) ||
5286               op == Op_AryEq || op == Op_StrComp || op == Op_CountPositives ||
5287               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy || op == Op_VectorizedHashCode ||
5288               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar || op == Op_FlatArrayCheck)) {
5289           n->dump();
5290           use->dump();
5291           assert(false, "EA: missing memory path");
5292         }
5293 #endif
5294       }
5295     }
5296   }
5297 
5298   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
5299   //            Walk each memory slice moving the first node encountered of each
5300   //            instance type to the input corresponding to its alias index.
5301   uint length = mergemem_worklist.length();
5302   for( uint next = 0; next < length; ++next ) {
5303     MergeMemNode* nmm = mergemem_worklist.at(next);
5304     assert(!visited.test_set(nmm->_idx), "should not be visited before");
5305     // Note: we don't want to use MergeMemStream here because we only want to
5306     // scan inputs which exist at the start, not ones we add during processing.
5307     // Note 2: MergeMem may already contains instance memory slices added
5308     // during find_inst_mem() call when memory nodes were processed above.
5309     igvn->hash_delete(nmm);
5310     uint nslices = MIN2(nmm->req(), new_index_start);
5311     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
5312       Node* mem = nmm->in(i);
5313       Node* cur = nullptr;
5314       if (mem == nullptr || mem->is_top()) {
5315         continue;
5316       }
5317       // First, update mergemem by moving memory nodes to corresponding slices
5318       // if their type became more precise since this mergemem was created.
5319       while (mem->is_Mem()) {
5320         const Type* at = igvn->type(mem->in(MemNode::Address));
5321         if (at != Type::TOP) {
5322           assert (at->isa_ptr() != nullptr, "pointer type required.");
5323           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
5324           if (idx == i) {
5325             if (cur == nullptr) {
5326               cur = mem;
5327             }
5328           } else {
5329             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
5330               nmm->set_memory_at(idx, mem);
5331             }
5332           }
5333         }
5334         mem = mem->in(MemNode::Memory);
5335       }
5336       nmm->set_memory_at(i, (cur != nullptr) ? cur : mem);
5337       // Find any instance of the current type if we haven't encountered
5338       // already a memory slice of the instance along the memory chain.
5339       for (uint ni = new_index_start; ni < new_index_end; ni++) {
5340         if((uint)_compile->get_general_index(ni) == i) {
5341           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
5342           if (nmm->is_empty_memory(m)) {
5343             Node* result = find_inst_mem(mem, ni, orig_phis);
5344             if (_compile->failing()) {
5345               return;
5346             }
5347             nmm->set_memory_at(ni, result);
5348           }
5349         }
5350       }
5351     }
5352     // Find the rest of instances values
5353     for (uint ni = new_index_start; ni < new_index_end; ni++) {
5354       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
5355       Node* result = step_through_mergemem(nmm, ni, tinst);
5356       if (result == nmm->base_memory()) {
5357         // Didn't find instance memory, search through general slice recursively.
5358         result = nmm->memory_at(_compile->get_general_index(ni));
5359         result = find_inst_mem(result, ni, orig_phis);
5360         if (_compile->failing()) {
5361           return;
5362         }
5363         nmm->set_memory_at(ni, result);
5364       }
5365     }
5366 
5367     // If we have crossed the 3/4 point of max node limit it's too risky
5368     // to continue with EA/SR because we might hit the max node limit.
5369     if (_compile->live_nodes() >= _compile->max_node_limit() * 0.75) {
5370       if (_compile->do_reduce_allocation_merges()) {
5371         _compile->record_failure(C2Compiler::retry_no_reduce_allocation_merges());
5372       } else if (_invocation > 0) {
5373         _compile->record_failure(C2Compiler::retry_no_iterative_escape_analysis());
5374       } else {
5375         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
5376       }
5377       return;
5378     }
5379 
5380     igvn->hash_insert(nmm);
5381     record_for_optimizer(nmm);
5382   }
5383 
5384   _compile->print_method(PHASE_EA_AFTER_SPLIT_UNIQUE_TYPES_3, 5);
5385 
5386   //  Phase 4:  Update the inputs of non-instance memory Phis and
5387   //            the Memory input of memnodes
5388   // First update the inputs of any non-instance Phi's from
5389   // which we split out an instance Phi.  Note we don't have
5390   // to recursively process Phi's encountered on the input memory
5391   // chains as is done in split_memory_phi() since they will
5392   // also be processed here.
5393   for (int j = 0; j < orig_phis.length(); j++) {
5394     PhiNode *phi = orig_phis.at(j);
5395     int alias_idx = _compile->get_alias_index(phi->adr_type());
5396     igvn->hash_delete(phi);
5397     for (uint i = 1; i < phi->req(); i++) {
5398       Node *mem = phi->in(i);
5399       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
5400       if (_compile->failing()) {
5401         return;
5402       }
5403       if (mem != new_mem) {
5404         phi->set_req(i, new_mem);
5405       }
5406     }
5407     igvn->hash_insert(phi);
5408     record_for_optimizer(phi);
5409   }
5410 
5411   // Update the memory inputs of MemNodes with the value we computed
5412   // in Phase 2 and move stores memory users to corresponding memory slices.
5413   // Disable memory split verification code until the fix for 6984348.
5414   // Currently it produces false negative results since it does not cover all cases.
5415 #if 0 // ifdef ASSERT
5416   visited.Reset();
5417   Node_Stack old_mems(arena, _compile->unique() >> 2);
5418 #endif
5419   for (uint i = 0; i < ideal_nodes.size(); i++) {
5420     Node*    n = ideal_nodes.at(i);
5421     Node* nmem = get_map(n->_idx);
5422     assert(nmem != nullptr, "sanity");
5423     if (n->is_Mem()) {
5424 #if 0 // ifdef ASSERT
5425       Node* old_mem = n->in(MemNode::Memory);
5426       if (!visited.test_set(old_mem->_idx)) {
5427         old_mems.push(old_mem, old_mem->outcnt());
5428       }
5429 #endif
5430       assert(n->in(MemNode::Memory) != nmem, "sanity");
5431       if (!n->is_Load()) {
5432         // Move memory users of a store first.
5433         move_inst_mem(n, orig_phis);
5434       }
5435       // Now update memory input
5436       igvn->hash_delete(n);
5437       n->set_req(MemNode::Memory, nmem);
5438       igvn->hash_insert(n);
5439       record_for_optimizer(n);
5440     } else {
5441       assert(n->is_Allocate() || n->is_CheckCastPP() ||
5442              n->is_AddP() || n->is_Phi() || n->is_NarrowMemProj(), "unknown node used for set_map()");
5443     }
5444   }
5445 #if 0 // ifdef ASSERT
5446   // Verify that memory was split correctly
5447   while (old_mems.is_nonempty()) {
5448     Node* old_mem = old_mems.node();
5449     uint  old_cnt = old_mems.index();
5450     old_mems.pop();
5451     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
5452   }
5453 #endif
5454   _compile->print_method(PHASE_EA_AFTER_SPLIT_UNIQUE_TYPES_4, 5);
5455 }
5456 
5457 #ifndef PRODUCT
5458 int ConnectionGraph::_no_escape_counter = 0;
5459 int ConnectionGraph::_arg_escape_counter = 0;
5460 int ConnectionGraph::_global_escape_counter = 0;
5461 
5462 static const char *node_type_names[] = {
5463   "UnknownType",
5464   "JavaObject",
5465   "LocalVar",
5466   "Field",
5467   "Arraycopy"
5468 };
5469 
5470 static const char *esc_names[] = {
5471   "UnknownEscape",
5472   "NoEscape",
5473   "ArgEscape",
5474   "GlobalEscape"
5475 };
5476 
5477 const char* PointsToNode::esc_name() const {
5478   return esc_names[(int)escape_state()];
5479 }
5480 
5481 void PointsToNode::dump_header(bool print_state, outputStream* out) const {
5482   NodeType nt = node_type();
5483   out->print("%s(%d) ", node_type_names[(int) nt], _pidx);
5484   if (print_state) {
5485     EscapeState es = escape_state();
5486     EscapeState fields_es = fields_escape_state();
5487     out->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
5488     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable()) {
5489       out->print("NSR ");
5490     }
5491   }
5492 }
5493 
5494 void PointsToNode::dump(bool print_state, outputStream* out, bool newline) const {
5495   dump_header(print_state, out);
5496   if (is_Field()) {
5497     FieldNode* f = (FieldNode*)this;
5498     if (f->is_oop()) {
5499       out->print("oop ");
5500     }
5501     if (f->offset() > 0) {
5502       out->print("+%d ", f->offset());
5503     }
5504     out->print("(");
5505     for (BaseIterator i(f); i.has_next(); i.next()) {
5506       PointsToNode* b = i.get();
5507       out->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
5508     }
5509     out->print(" )");
5510   }
5511   out->print("[");
5512   for (EdgeIterator i(this); i.has_next(); i.next()) {
5513     PointsToNode* e = i.get();
5514     out->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
5515   }
5516   out->print(" [");
5517   for (UseIterator i(this); i.has_next(); i.next()) {
5518     PointsToNode* u = i.get();
5519     bool is_base = false;
5520     if (PointsToNode::is_base_use(u)) {
5521       is_base = true;
5522       u = PointsToNode::get_use_node(u)->as_Field();
5523     }
5524     out->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
5525   }
5526   out->print(" ]]  ");
5527   if (_node == nullptr) {
5528     out->print("<null>%s", newline ? "\n" : "");
5529   } else {
5530     _node->dump(newline ? "\n" : "", false, out);
5531   }
5532 }
5533 
5534 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
5535   bool first = true;
5536   int ptnodes_length = ptnodes_worklist.length();
5537   for (int i = 0; i < ptnodes_length; i++) {
5538     PointsToNode *ptn = ptnodes_worklist.at(i);
5539     if (ptn == nullptr || !ptn->is_JavaObject()) {
5540       continue;
5541     }
5542     PointsToNode::EscapeState es = ptn->escape_state();
5543     if ((es != PointsToNode::NoEscape) && !Verbose) {
5544       continue;
5545     }
5546     Node* n = ptn->ideal_node();
5547     if (n->is_Allocate() || (n->is_CallStaticJava() &&
5548                              n->as_CallStaticJava()->is_boxing_method())) {
5549       if (first) {
5550         tty->cr();
5551         tty->print("======== Connection graph for ");
5552         _compile->method()->print_short_name();
5553         tty->cr();
5554         tty->print_cr("invocation #%d: %d iterations and %f sec to build connection graph with %d nodes and worklist size %d",
5555                       _invocation, _build_iterations, _build_time, nodes_size(), ptnodes_worklist.length());
5556         tty->cr();
5557         first = false;
5558       }
5559       ptn->dump();
5560       // Print all locals and fields which reference this allocation
5561       for (UseIterator j(ptn); j.has_next(); j.next()) {
5562         PointsToNode* use = j.get();
5563         if (use->is_LocalVar()) {
5564           use->dump(Verbose);
5565         } else if (Verbose) {
5566           use->dump();
5567         }
5568       }
5569       tty->cr();
5570     }
5571   }
5572 }
5573 
5574 void ConnectionGraph::print_statistics() {
5575   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));
5576 }
5577 
5578 void ConnectionGraph::escape_state_statistics(GrowableArray<JavaObjectNode*>& java_objects_worklist) {
5579   if (!PrintOptoStatistics || (_invocation > 0)) { // Collect data only for the first invocation
5580     return;
5581   }
5582   for (int next = 0; next < java_objects_worklist.length(); ++next) {
5583     JavaObjectNode* ptn = java_objects_worklist.at(next);
5584     if (ptn->ideal_node()->is_Allocate()) {
5585       if (ptn->escape_state() == PointsToNode::NoEscape) {
5586         AtomicAccess::inc(&ConnectionGraph::_no_escape_counter);
5587       } else if (ptn->escape_state() == PointsToNode::ArgEscape) {
5588         AtomicAccess::inc(&ConnectionGraph::_arg_escape_counter);
5589       } else if (ptn->escape_state() == PointsToNode::GlobalEscape) {
5590         AtomicAccess::inc(&ConnectionGraph::_global_escape_counter);
5591       } else {
5592         assert(false, "Unexpected Escape State");
5593       }
5594     }
5595   }
5596 }
5597 
5598 void ConnectionGraph::trace_es_update_helper(PointsToNode* ptn, PointsToNode::EscapeState es, bool fields, const char* reason) const {
5599   if (_compile->directive()->TraceEscapeAnalysisOption) {
5600     assert(ptn != nullptr, "should not be null");
5601     assert(reason != nullptr, "should not be null");
5602     ptn->dump_header(true);
5603     PointsToNode::EscapeState new_es = fields ? ptn->escape_state() : es;
5604     PointsToNode::EscapeState new_fields_es = fields ? es : ptn->fields_escape_state();
5605     tty->print_cr("-> %s(%s) %s", esc_names[(int)new_es], esc_names[(int)new_fields_es], reason);
5606   }
5607 }
5608 
5609 const char* ConnectionGraph::trace_propagate_message(PointsToNode* from) const {
5610   if (_compile->directive()->TraceEscapeAnalysisOption) {
5611     stringStream ss;
5612     ss.print("propagated from: ");
5613     from->dump(true, &ss, false);
5614     return ss.as_string();
5615   } else {
5616     return nullptr;
5617   }
5618 }
5619 
5620 const char* ConnectionGraph::trace_arg_escape_message(CallNode* call) const {
5621   if (_compile->directive()->TraceEscapeAnalysisOption) {
5622     stringStream ss;
5623     ss.print("escapes as arg to:");
5624     call->dump("", false, &ss);
5625     return ss.as_string();
5626   } else {
5627     return nullptr;
5628   }
5629 }
5630 
5631 const char* ConnectionGraph::trace_merged_message(PointsToNode* other) const {
5632   if (_compile->directive()->TraceEscapeAnalysisOption) {
5633     stringStream ss;
5634     ss.print("is merged with other object: ");
5635     other->dump_header(true, &ss);
5636     return ss.as_string();
5637   } else {
5638     return nullptr;
5639   }
5640 }
5641 
5642 #endif
5643 
5644 void ConnectionGraph::record_for_optimizer(Node *n) {
5645   _igvn->_worklist.push(n);
5646   _igvn->add_users_to_worklist(n);
5647 }
--- EOF ---