1 /*
   2  * Copyright (c) 2005, 2020, 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 "precompiled.hpp"
  26 #include "ci/bcEscapeAnalyzer.hpp"
  27 #include "compiler/compileLog.hpp"
  28 #include "gc/shared/barrierSet.hpp"
  29 #include "gc/shared/c2/barrierSetC2.hpp"
  30 #include "libadt/vectset.hpp"
  31 #include "memory/allocation.hpp"
  32 #include "memory/resourceArea.hpp"
  33 #include "opto/c2compiler.hpp"
  34 #include "opto/arraycopynode.hpp"
  35 #include "opto/callnode.hpp"
  36 #include "opto/cfgnode.hpp"
  37 #include "opto/compile.hpp"
  38 #include "opto/escape.hpp"
  39 #include "opto/phaseX.hpp"
  40 #include "opto/movenode.hpp"
  41 #include "opto/rootnode.hpp"
  42 #include "utilities/macros.hpp"
  43 
  44 ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :
  45   _nodes(C->comp_arena(), C->unique(), C->unique(), NULL),
  46   _in_worklist(C->comp_arena()),
  47   _next_pidx(0),
  48   _collecting(true),
  49   _verify(false),
  50   _compile(C),
  51   _igvn(igvn),
  52   _node_map(C->comp_arena()) {
  53   // Add unknown java object.
  54   add_java_object(C->top(), PointsToNode::GlobalEscape);
  55   phantom_obj = ptnode_adr(C->top()->_idx)->as_JavaObject();
  56   // Add ConP(#NULL) and ConN(#NULL) nodes.
  57   Node* oop_null = igvn->zerocon(T_OBJECT);
  58   assert(oop_null->_idx < nodes_size(), "should be created already");
  59   add_java_object(oop_null, PointsToNode::NoEscape);
  60   null_obj = ptnode_adr(oop_null->_idx)->as_JavaObject();
  61   if (UseCompressedOops) {
  62     Node* noop_null = igvn->zerocon(T_NARROWOOP);
  63     assert(noop_null->_idx < nodes_size(), "should be created already");
  64     map_ideal_node(noop_null, null_obj);
  65   }
  66   _pcmp_neq = NULL; // Should be initialized
  67   _pcmp_eq  = NULL;
  68 }
  69 
  70 bool ConnectionGraph::has_candidates(Compile *C) {
  71   // EA brings benefits only when the code has allocations and/or locks which
  72   // are represented by ideal Macro nodes.
  73   int cnt = C->macro_count();
  74   for (int i = 0; i < cnt; i++) {
  75     Node *n = C->macro_node(i);
  76     if (n->is_Allocate())
  77       return true;
  78     if (n->is_Lock()) {
  79       Node* obj = n->as_Lock()->obj_node()->uncast();
  80       if (!(obj->is_Parm() || obj->is_Con()))
  81         return true;
  82     }
  83     if (n->is_CallStaticJava() &&
  84         n->as_CallStaticJava()->is_boxing_method()) {
  85       return true;
  86     }
  87   }
  88   return false;
  89 }
  90 
  91 void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {
  92   Compile::TracePhase tp("escapeAnalysis", &Phase::timers[Phase::_t_escapeAnalysis]);
  93   ResourceMark rm;
  94 
  95   // Add ConP#NULL and ConN#NULL nodes before ConnectionGraph construction
  96   // to create space for them in ConnectionGraph::_nodes[].
  97   Node* oop_null = igvn->zerocon(T_OBJECT);
  98   Node* noop_null = igvn->zerocon(T_NARROWOOP);
  99   ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn);
 100   // Perform escape analysis
 101   if (congraph->compute_escape()) {
 102     // There are non escaping objects.
 103     C->set_congraph(congraph);
 104   }
 105   // Cleanup.
 106   if (oop_null->outcnt() == 0)
 107     igvn->hash_delete(oop_null);
 108   if (noop_null->outcnt() == 0)
 109     igvn->hash_delete(noop_null);
 110 }
 111 
 112 bool ConnectionGraph::compute_escape() {
 113   Compile* C = _compile;
 114   PhaseGVN* igvn = _igvn;
 115 
 116   // Worklists used by EA.
 117   Unique_Node_List delayed_worklist;
 118   GrowableArray<Node*> alloc_worklist;
 119   GrowableArray<Node*> ptr_cmp_worklist;
 120   GrowableArray<Node*> storestore_worklist;
 121   GrowableArray<ArrayCopyNode*> arraycopy_worklist;
 122   GrowableArray<PointsToNode*>   ptnodes_worklist;
 123   GrowableArray<JavaObjectNode*> java_objects_worklist;
 124   GrowableArray<JavaObjectNode*> non_escaped_worklist;
 125   GrowableArray<FieldNode*>      oop_fields_worklist;
 126   DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
 127 
 128   { Compile::TracePhase tp("connectionGraph", &Phase::timers[Phase::_t_connectionGraph]);
 129 
 130   // 1. Populate Connection Graph (CG) with PointsTo nodes.
 131   ideal_nodes.map(C->live_nodes(), NULL);  // preallocate space
 132   // Initialize worklist
 133   if (C->root() != NULL) {
 134     ideal_nodes.push(C->root());
 135   }
 136   // Processed ideal nodes are unique on ideal_nodes list
 137   // but several ideal nodes are mapped to the phantom_obj.
 138   // To avoid duplicated entries on the following worklists
 139   // add the phantom_obj only once to them.
 140   ptnodes_worklist.append(phantom_obj);
 141   java_objects_worklist.append(phantom_obj);
 142   for( uint next = 0; next < ideal_nodes.size(); ++next ) {
 143     Node* n = ideal_nodes.at(next);
 144     // Create PointsTo nodes and add them to Connection Graph. Called
 145     // only once per ideal node since ideal_nodes is Unique_Node list.
 146     add_node_to_connection_graph(n, &delayed_worklist);
 147     PointsToNode* ptn = ptnode_adr(n->_idx);
 148     if (ptn != NULL && ptn != phantom_obj) {
 149       ptnodes_worklist.append(ptn);
 150       if (ptn->is_JavaObject()) {
 151         java_objects_worklist.append(ptn->as_JavaObject());
 152         if ((n->is_Allocate() || n->is_CallStaticJava()) &&
 153             (ptn->escape_state() < PointsToNode::GlobalEscape)) {
 154           // Only allocations and java static calls results are interesting.
 155           non_escaped_worklist.append(ptn->as_JavaObject());
 156         }
 157       } else if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
 158         oop_fields_worklist.append(ptn->as_Field());
 159       }
 160     }
 161     if (n->is_MergeMem()) {
 162       // Collect all MergeMem nodes to add memory slices for
 163       // scalar replaceable objects in split_unique_types().
 164       _mergemem_worklist.append(n->as_MergeMem());
 165     } else if (OptimizePtrCompare && n->is_Cmp() &&
 166                (n->Opcode() == Op_CmpP || n->Opcode() == Op_CmpN)) {
 167       // Collect compare pointers nodes.
 168       ptr_cmp_worklist.append(n);
 169     } else if (n->is_MemBarStoreStore()) {
 170       // Collect all MemBarStoreStore nodes so that depending on the
 171       // escape status of the associated Allocate node some of them
 172       // may be eliminated.
 173       storestore_worklist.append(n);
 174     } else if (n->is_MemBar() && (n->Opcode() == Op_MemBarRelease) &&
 175                (n->req() > MemBarNode::Precedent)) {
 176       record_for_optimizer(n);
 177 #ifdef ASSERT
 178     } else if (n->is_AddP()) {
 179       // Collect address nodes for graph verification.
 180       addp_worklist.append(n);
 181 #endif
 182     } else if (n->is_ArrayCopy()) {
 183       // Keep a list of ArrayCopy nodes so if one of its input is non
 184       // escaping, we can record a unique type
 185       arraycopy_worklist.append(n->as_ArrayCopy());
 186     }
 187     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 188       Node* m = n->fast_out(i);   // Get user
 189       ideal_nodes.push(m);
 190     }
 191   }
 192   if (non_escaped_worklist.length() == 0) {
 193     _collecting = false;
 194     return false; // Nothing to do.
 195   }
 196   // Add final simple edges to graph.
 197   while(delayed_worklist.size() > 0) {
 198     Node* n = delayed_worklist.pop();
 199     add_final_edges(n);
 200   }
 201   int ptnodes_length = ptnodes_worklist.length();
 202 
 203 #ifdef ASSERT
 204   if (VerifyConnectionGraph) {
 205     // Verify that no new simple edges could be created and all
 206     // local vars has edges.
 207     _verify = true;
 208     for (int next = 0; next < ptnodes_length; ++next) {
 209       PointsToNode* ptn = ptnodes_worklist.at(next);
 210       add_final_edges(ptn->ideal_node());
 211       if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
 212         ptn->dump();
 213         assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
 214       }
 215     }
 216     _verify = false;
 217   }
 218 #endif
 219   // Bytecode analyzer BCEscapeAnalyzer, used for Call nodes
 220   // processing, calls to CI to resolve symbols (types, fields, methods)
 221   // referenced in bytecode. During symbol resolution VM may throw
 222   // an exception which CI cleans and converts to compilation failure.
 223   if (C->failing())  return false;
 224 
 225   // 2. Finish Graph construction by propagating references to all
 226   //    java objects through graph.
 227   if (!complete_connection_graph(ptnodes_worklist, non_escaped_worklist,
 228                                  java_objects_worklist, oop_fields_worklist)) {
 229     // All objects escaped or hit time or iterations limits.
 230     _collecting = false;
 231     return false;
 232   }
 233 
 234   // 3. Adjust scalar_replaceable state of nonescaping objects and push
 235   //    scalar replaceable allocations on alloc_worklist for processing
 236   //    in split_unique_types().
 237   int non_escaped_length = non_escaped_worklist.length();
 238   for (int next = 0; next < non_escaped_length; next++) {
 239     JavaObjectNode* ptn = non_escaped_worklist.at(next);
 240     bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
 241     Node* n = ptn->ideal_node();
 242     if (n->is_Allocate()) {
 243       n->as_Allocate()->_is_non_escaping = noescape;
 244     }
 245     if (n->is_CallStaticJava()) {
 246       n->as_CallStaticJava()->_is_non_escaping = noescape;
 247     }
 248     if (noescape && ptn->scalar_replaceable()) {
 249       adjust_scalar_replaceable_state(ptn);
 250       if (ptn->scalar_replaceable()) {
 251         alloc_worklist.append(ptn->ideal_node());
 252       }
 253     }
 254   }
 255 
 256 #ifdef ASSERT
 257   if (VerifyConnectionGraph) {
 258     // Verify that graph is complete - no new edges could be added or needed.
 259     verify_connection_graph(ptnodes_worklist, non_escaped_worklist,
 260                             java_objects_worklist, addp_worklist);
 261   }
 262   assert(C->unique() == nodes_size(), "no new ideal nodes should be added during ConnectionGraph build");
 263   assert(null_obj->escape_state() == PointsToNode::NoEscape &&
 264          null_obj->edge_count() == 0 &&
 265          !null_obj->arraycopy_src() &&
 266          !null_obj->arraycopy_dst(), "sanity");
 267 #endif
 268 
 269   _collecting = false;
 270 
 271   } // TracePhase t3("connectionGraph")
 272 
 273   // 4. Optimize ideal graph based on EA information.
 274   bool has_non_escaping_obj = (non_escaped_worklist.length() > 0);
 275   if (has_non_escaping_obj) {
 276     optimize_ideal_graph(ptr_cmp_worklist, storestore_worklist);
 277   }
 278 
 279 #ifndef PRODUCT
 280   if (PrintEscapeAnalysis) {
 281     dump(ptnodes_worklist); // Dump ConnectionGraph
 282   }
 283 #endif
 284 
 285   bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
 286 #ifdef ASSERT
 287   if (VerifyConnectionGraph) {
 288     int alloc_length = alloc_worklist.length();
 289     for (int next = 0; next < alloc_length; ++next) {
 290       Node* n = alloc_worklist.at(next);
 291       PointsToNode* ptn = ptnode_adr(n->_idx);
 292       assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
 293     }
 294   }
 295 #endif
 296 
 297   // 5. Separate memory graph for scalar replaceable allcations.
 298   if (has_scalar_replaceable_candidates &&
 299       C->AliasLevel() >= 3 && EliminateAllocations) {
 300     // Now use the escape information to create unique types for
 301     // scalar replaceable objects.
 302     split_unique_types(alloc_worklist, arraycopy_worklist);
 303     if (C->failing())  return false;
 304     C->print_method(PHASE_AFTER_EA, 2);
 305 
 306 #ifdef ASSERT
 307   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
 308     tty->print("=== No allocations eliminated for ");
 309     C->method()->print_short_name();
 310     if(!EliminateAllocations) {
 311       tty->print(" since EliminateAllocations is off ===");
 312     } else if(!has_scalar_replaceable_candidates) {
 313       tty->print(" since there are no scalar replaceable candidates ===");
 314     } else if(C->AliasLevel() < 3) {
 315       tty->print(" since AliasLevel < 3 ===");
 316     }
 317     tty->cr();
 318 #endif
 319   }
 320   return has_non_escaping_obj;
 321 }
 322 
 323 // Utility function for nodes that load an object
 324 void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 325   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 326   // ThreadLocal has RawPtr type.
 327   const Type* t = _igvn->type(n);
 328   if (t->make_ptr() != NULL) {
 329     Node* adr = n->in(MemNode::Address);
 330 #ifdef ASSERT
 331     if (!adr->is_AddP()) {
 332       assert(_igvn->type(adr)->isa_rawptr(), "sanity");
 333     } else {
 334       assert((ptnode_adr(adr->_idx) == NULL ||
 335               ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
 336     }
 337 #endif
 338     add_local_var_and_edge(n, PointsToNode::NoEscape,
 339                            adr, delayed_worklist);
 340   }
 341 }
 342 
 343 // Populate Connection Graph with PointsTo nodes and create simple
 344 // connection graph edges.
 345 void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 346   assert(!_verify, "this method should not be called for verification");
 347   PhaseGVN* igvn = _igvn;
 348   uint n_idx = n->_idx;
 349   PointsToNode* n_ptn = ptnode_adr(n_idx);
 350   if (n_ptn != NULL)
 351     return; // No need to redefine PointsTo node during first iteration.
 352 
 353   int opcode = n->Opcode();
 354   bool gc_handled = BarrierSet::barrier_set()->barrier_set_c2()->escape_add_to_con_graph(this, igvn, delayed_worklist, n, opcode);
 355   if (gc_handled) {
 356     return; // Ignore node if already handled by GC.
 357   }
 358 
 359   if (n->is_Call()) {
 360     // Arguments to allocation and locking don't escape.
 361     if (n->is_AbstractLock()) {
 362       // Put Lock and Unlock nodes on IGVN worklist to process them during
 363       // first IGVN optimization when escape information is still available.
 364       record_for_optimizer(n);
 365     } else if (n->is_Allocate()) {
 366       add_call_node(n->as_Call());
 367       record_for_optimizer(n);
 368     } else {
 369       if (n->is_CallStaticJava()) {
 370         const char* name = n->as_CallStaticJava()->_name;
 371         if (name != NULL && strcmp(name, "uncommon_trap") == 0)
 372           return; // Skip uncommon traps
 373       }
 374       // Don't mark as processed since call's arguments have to be processed.
 375       delayed_worklist->push(n);
 376       // Check if a call returns an object.
 377       if ((n->as_Call()->returns_pointer() &&
 378            n->as_Call()->proj_out_or_null(TypeFunc::Parms) != NULL) ||
 379           (n->is_CallStaticJava() &&
 380            n->as_CallStaticJava()->is_boxing_method())) {
 381         add_call_node(n->as_Call());
 382       }
 383     }
 384     return;
 385   }
 386   // Put this check here to process call arguments since some call nodes
 387   // point to phantom_obj.
 388   if (n_ptn == phantom_obj || n_ptn == null_obj)
 389     return; // Skip predefined nodes.
 390 
 391   switch (opcode) {
 392     case Op_AddP: {
 393       Node* base = get_addp_base(n);
 394       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 395       // Field nodes are created for all field types. They are used in
 396       // adjust_scalar_replaceable_state() and split_unique_types().
 397       // Note, non-oop fields will have only base edges in Connection
 398       // Graph because such fields are not used for oop loads and stores.
 399       int offset = address_offset(n, igvn);
 400       add_field(n, PointsToNode::NoEscape, offset);
 401       if (ptn_base == NULL) {
 402         delayed_worklist->push(n); // Process it later.
 403       } else {
 404         n_ptn = ptnode_adr(n_idx);
 405         add_base(n_ptn->as_Field(), ptn_base);
 406       }
 407       break;
 408     }
 409     case Op_CastX2P: {
 410       map_ideal_node(n, phantom_obj);
 411       break;
 412     }
 413     case Op_CastPP:
 414     case Op_CheckCastPP:
 415     case Op_EncodeP:
 416     case Op_DecodeN:
 417     case Op_EncodePKlass:
 418     case Op_DecodeNKlass: {
 419       add_local_var_and_edge(n, PointsToNode::NoEscape,
 420                              n->in(1), delayed_worklist);
 421       break;
 422     }
 423     case Op_CMoveP: {
 424       add_local_var(n, PointsToNode::NoEscape);
 425       // Do not add edges during first iteration because some could be
 426       // not defined yet.
 427       delayed_worklist->push(n);
 428       break;
 429     }
 430     case Op_ConP:
 431     case Op_ConN:
 432     case Op_ConNKlass: {
 433       // assume all oop constants globally escape except for null
 434       PointsToNode::EscapeState es;
 435       const Type* t = igvn->type(n);
 436       if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
 437         es = PointsToNode::NoEscape;
 438       } else {
 439         es = PointsToNode::GlobalEscape;
 440       }
 441       add_java_object(n, es);
 442       break;
 443     }
 444     case Op_CreateEx: {
 445       // assume that all exception objects globally escape
 446       map_ideal_node(n, phantom_obj);
 447       break;
 448     }
 449     case Op_LoadKlass:
 450     case Op_LoadNKlass: {
 451       // Unknown class is loaded
 452       map_ideal_node(n, phantom_obj);
 453       break;
 454     }
 455     case Op_LoadP:
 456     case Op_LoadN:
 457     case Op_LoadPLocked: {
 458       add_objload_to_connection_graph(n, delayed_worklist);
 459       break;
 460     }
 461     case Op_Parm: {
 462       map_ideal_node(n, phantom_obj);
 463       break;
 464     }
 465     case Op_PartialSubtypeCheck: {
 466       // Produces Null or notNull and is used in only in CmpP so
 467       // phantom_obj could be used.
 468       map_ideal_node(n, phantom_obj); // Result is unknown
 469       break;
 470     }
 471     case Op_Phi: {
 472       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 473       // ThreadLocal has RawPtr type.
 474       const Type* t = n->as_Phi()->type();
 475       if (t->make_ptr() != NULL) {
 476         add_local_var(n, PointsToNode::NoEscape);
 477         // Do not add edges during first iteration because some could be
 478         // not defined yet.
 479         delayed_worklist->push(n);
 480       }
 481       break;
 482     }
 483     case Op_Proj: {
 484       // we are only interested in the oop result projection from a call
 485       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 486           n->in(0)->as_Call()->returns_pointer()) {
 487         add_local_var_and_edge(n, PointsToNode::NoEscape,
 488                                n->in(0), delayed_worklist);
 489       }
 490       break;
 491     }
 492     case Op_Rethrow: // Exception object escapes
 493     case Op_Return: {
 494       if (n->req() > TypeFunc::Parms &&
 495           igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 496         // Treat Return value as LocalVar with GlobalEscape escape state.
 497         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 498                                n->in(TypeFunc::Parms), delayed_worklist);
 499       }
 500       break;
 501     }
 502     case Op_CompareAndExchangeP:
 503     case Op_CompareAndExchangeN:
 504     case Op_GetAndSetP:
 505     case Op_GetAndSetN: {
 506       add_objload_to_connection_graph(n, delayed_worklist);
 507       // fallthrough
 508     }
 509     case Op_StoreP:
 510     case Op_StoreN:
 511     case Op_StoreNKlass:
 512     case Op_StorePConditional:
 513     case Op_WeakCompareAndSwapP:
 514     case Op_WeakCompareAndSwapN:
 515     case Op_CompareAndSwapP:
 516     case Op_CompareAndSwapN: {
 517       add_to_congraph_unsafe_access(n, opcode, delayed_worklist);
 518       break;
 519     }
 520     case Op_AryEq:
 521     case Op_HasNegatives:
 522     case Op_StrComp:
 523     case Op_StrEquals:
 524     case Op_StrIndexOf:
 525     case Op_StrIndexOfChar:
 526     case Op_StrInflatedCopy:
 527     case Op_StrCompressedCopy:
 528     case Op_EncodeISOArray: {
 529       add_local_var(n, PointsToNode::ArgEscape);
 530       delayed_worklist->push(n); // Process it later.
 531       break;
 532     }
 533     case Op_ThreadLocal: {
 534       add_java_object(n, PointsToNode::ArgEscape);
 535       break;
 536     }
 537     default:
 538       ; // Do nothing for nodes not related to EA.
 539   }
 540   return;
 541 }
 542 
 543 #ifdef ASSERT
 544 #define ELSE_FAIL(name)                               \
 545       /* Should not be called for not pointer type. */  \
 546       n->dump(1);                                       \
 547       assert(false, name);                              \
 548       break;
 549 #else
 550 #define ELSE_FAIL(name) \
 551       break;
 552 #endif
 553 
 554 // Add final simple edges to graph.
 555 void ConnectionGraph::add_final_edges(Node *n) {
 556   PointsToNode* n_ptn = ptnode_adr(n->_idx);
 557 #ifdef ASSERT
 558   if (_verify && n_ptn->is_JavaObject())
 559     return; // This method does not change graph for JavaObject.
 560 #endif
 561 
 562   if (n->is_Call()) {
 563     process_call_arguments(n->as_Call());
 564     return;
 565   }
 566   assert(n->is_Store() || n->is_LoadStore() ||
 567          (n_ptn != NULL) && (n_ptn->ideal_node() != NULL),
 568          "node should be registered already");
 569   int opcode = n->Opcode();
 570   bool gc_handled = BarrierSet::barrier_set()->barrier_set_c2()->escape_add_final_edges(this, _igvn, n, opcode);
 571   if (gc_handled) {
 572     return; // Ignore node if already handled by GC.
 573   }
 574   switch (opcode) {
 575     case Op_AddP: {
 576       Node* base = get_addp_base(n);
 577       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 578       assert(ptn_base != NULL, "field's base should be registered");
 579       add_base(n_ptn->as_Field(), ptn_base);
 580       break;
 581     }
 582     case Op_CastPP:
 583     case Op_CheckCastPP:
 584     case Op_EncodeP:
 585     case Op_DecodeN:
 586     case Op_EncodePKlass:
 587     case Op_DecodeNKlass: {
 588       add_local_var_and_edge(n, PointsToNode::NoEscape,
 589                              n->in(1), NULL);
 590       break;
 591     }
 592     case Op_CMoveP: {
 593       for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
 594         Node* in = n->in(i);
 595         if (in == NULL)
 596           continue;  // ignore NULL
 597         Node* uncast_in = in->uncast();
 598         if (uncast_in->is_top() || uncast_in == n)
 599           continue;  // ignore top or inputs which go back this node
 600         PointsToNode* ptn = ptnode_adr(in->_idx);
 601         assert(ptn != NULL, "node should be registered");
 602         add_edge(n_ptn, ptn);
 603       }
 604       break;
 605     }
 606     case Op_LoadP:
 607     case Op_LoadN:
 608     case Op_LoadPLocked: {
 609       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 610       // ThreadLocal has RawPtr type.
 611       const Type* t = _igvn->type(n);
 612       if (t->make_ptr() != NULL) {
 613         Node* adr = n->in(MemNode::Address);
 614         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 615         break;
 616       }
 617       ELSE_FAIL("Op_LoadP");
 618     }
 619     case Op_Phi: {
 620       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 621       // ThreadLocal has RawPtr type.
 622       const Type* t = n->as_Phi()->type();
 623       if (t->make_ptr() != NULL) {
 624         for (uint i = 1; i < n->req(); i++) {
 625           Node* in = n->in(i);
 626           if (in == NULL)
 627             continue;  // ignore NULL
 628           Node* uncast_in = in->uncast();
 629           if (uncast_in->is_top() || uncast_in == n)
 630             continue;  // ignore top or inputs which go back this node
 631           PointsToNode* ptn = ptnode_adr(in->_idx);
 632           assert(ptn != NULL, "node should be registered");
 633           add_edge(n_ptn, ptn);
 634         }
 635         break;
 636       }
 637       ELSE_FAIL("Op_Phi");
 638     }
 639     case Op_Proj: {
 640       // we are only interested in the oop result projection from a call
 641       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 642           n->in(0)->as_Call()->returns_pointer()) {
 643         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), NULL);
 644         break;
 645       }
 646       ELSE_FAIL("Op_Proj");
 647     }
 648     case Op_Rethrow: // Exception object escapes
 649     case Op_Return: {
 650       if (n->req() > TypeFunc::Parms &&
 651           _igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 652         // Treat Return value as LocalVar with GlobalEscape escape state.
 653         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 654                                n->in(TypeFunc::Parms), NULL);
 655         break;
 656       }
 657       ELSE_FAIL("Op_Return");
 658     }
 659     case Op_StoreP:
 660     case Op_StoreN:
 661     case Op_StoreNKlass:
 662     case Op_StorePConditional:
 663     case Op_CompareAndExchangeP:
 664     case Op_CompareAndExchangeN:
 665     case Op_CompareAndSwapP:
 666     case Op_CompareAndSwapN:
 667     case Op_WeakCompareAndSwapP:
 668     case Op_WeakCompareAndSwapN:
 669     case Op_GetAndSetP:
 670     case Op_GetAndSetN: {
 671       if (add_final_edges_unsafe_access(n, opcode)) {
 672         break;
 673       }
 674       ELSE_FAIL("Op_StoreP");
 675     }
 676     case Op_AryEq:
 677     case Op_HasNegatives:
 678     case Op_StrComp:
 679     case Op_StrEquals:
 680     case Op_StrIndexOf:
 681     case Op_StrIndexOfChar:
 682     case Op_StrInflatedCopy:
 683     case Op_StrCompressedCopy:
 684     case Op_EncodeISOArray: {
 685       // char[]/byte[] arrays passed to string intrinsic do not escape but
 686       // they are not scalar replaceable. Adjust escape state for them.
 687       // Start from in(2) edge since in(1) is memory edge.
 688       for (uint i = 2; i < n->req(); i++) {
 689         Node* adr = n->in(i);
 690         const Type* at = _igvn->type(adr);
 691         if (!adr->is_top() && at->isa_ptr()) {
 692           assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
 693                  at->isa_ptr() != NULL, "expecting a pointer");
 694           if (adr->is_AddP()) {
 695             adr = get_addp_base(adr);
 696           }
 697           PointsToNode* ptn = ptnode_adr(adr->_idx);
 698           assert(ptn != NULL, "node should be registered");
 699           add_edge(n_ptn, ptn);
 700         }
 701       }
 702       break;
 703     }
 704     default: {
 705       // This method should be called only for EA specific nodes which may
 706       // miss some edges when they were created.
 707 #ifdef ASSERT
 708       n->dump(1);
 709 #endif
 710       guarantee(false, "unknown node");
 711     }
 712   }
 713   return;
 714 }
 715 
 716 void ConnectionGraph::add_to_congraph_unsafe_access(Node* n, uint opcode, Unique_Node_List* delayed_worklist) {
 717   Node* adr = n->in(MemNode::Address);
 718   const Type* adr_type = _igvn->type(adr);
 719   adr_type = adr_type->make_ptr();
 720   if (adr_type == NULL) {
 721     return; // skip dead nodes
 722   }
 723   if (adr_type->isa_oopptr()
 724       || ((opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass)
 725           && adr_type == TypeRawPtr::NOTNULL
 726           && is_captured_store_address(adr))) {
 727     delayed_worklist->push(n); // Process it later.
 728 #ifdef ASSERT
 729     assert (adr->is_AddP(), "expecting an AddP");
 730     if (adr_type == TypeRawPtr::NOTNULL) {
 731       // Verify a raw address for a store captured by Initialize node.
 732       int offs = (int) _igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 733       assert(offs != Type::OffsetBot, "offset must be a constant");
 734     }
 735 #endif
 736   } else {
 737     // Ignore copy the displaced header to the BoxNode (OSR compilation).
 738     if (adr->is_BoxLock()) {
 739       return;
 740     }
 741     // Stored value escapes in unsafe access.
 742     if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
 743       delayed_worklist->push(n); // Process unsafe access later.
 744       return;
 745     }
 746 #ifdef ASSERT
 747     n->dump(1);
 748     assert(false, "not unsafe");
 749 #endif
 750   }
 751 }
 752 
 753 bool ConnectionGraph::add_final_edges_unsafe_access(Node* n, uint opcode) {
 754   Node* adr = n->in(MemNode::Address);
 755   const Type *adr_type = _igvn->type(adr);
 756   adr_type = adr_type->make_ptr();
 757 #ifdef ASSERT
 758   if (adr_type == NULL) {
 759     n->dump(1);
 760     assert(adr_type != NULL, "dead node should not be on list");
 761     return true;
 762   }
 763 #endif
 764 
 765   if (opcode == Op_GetAndSetP || opcode == Op_GetAndSetN ||
 766       opcode == Op_CompareAndExchangeN || opcode == Op_CompareAndExchangeP) {
 767     add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 768   }
 769 
 770   if (adr_type->isa_oopptr()
 771       || ((opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass)
 772            && adr_type == TypeRawPtr::NOTNULL
 773            && is_captured_store_address(adr))) {
 774     // Point Address to Value
 775     PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 776     assert(adr_ptn != NULL &&
 777            adr_ptn->as_Field()->is_oop(), "node should be registered");
 778     Node* val = n->in(MemNode::ValueIn);
 779     PointsToNode* ptn = ptnode_adr(val->_idx);
 780     assert(ptn != NULL, "node should be registered");
 781     add_edge(adr_ptn, ptn);
 782     return true;
 783   } else if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
 784     // Stored value escapes in unsafe access.
 785     Node* val = n->in(MemNode::ValueIn);
 786     PointsToNode* ptn = ptnode_adr(val->_idx);
 787     assert(ptn != NULL, "node should be registered");
 788     set_escape_state(ptn, PointsToNode::GlobalEscape);
 789     // Add edge to object for unsafe access with offset.
 790     PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 791     assert(adr_ptn != NULL, "node should be registered");
 792     if (adr_ptn->is_Field()) {
 793       assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
 794       add_edge(adr_ptn, ptn);
 795     }
 796     return true;
 797   }
 798   return false;
 799 }
 800 
 801 void ConnectionGraph::add_call_node(CallNode* call) {
 802   assert(call->returns_pointer(), "only for call which returns pointer");
 803   uint call_idx = call->_idx;
 804   if (call->is_Allocate()) {
 805     Node* k = call->in(AllocateNode::KlassNode);
 806     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
 807     assert(kt != NULL, "TypeKlassPtr  required.");
 808     ciKlass* cik = kt->klass();
 809     PointsToNode::EscapeState es = PointsToNode::NoEscape;
 810     bool scalar_replaceable = true;
 811     if (call->is_AllocateArray()) {
 812       if (!cik->is_array_klass()) { // StressReflectiveCode
 813         es = PointsToNode::GlobalEscape;
 814       } else {
 815         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
 816         if (length < 0 || length > EliminateAllocationArraySizeLimit) {
 817           // Not scalar replaceable if the length is not constant or too big.
 818           scalar_replaceable = false;
 819         }
 820       }
 821     } else {  // Allocate instance
 822       if (cik->is_subclass_of(_compile->env()->Thread_klass()) ||
 823           cik->is_subclass_of(_compile->env()->Reference_klass()) ||
 824          !cik->is_instance_klass() || // StressReflectiveCode
 825          !cik->as_instance_klass()->can_be_instantiated() ||
 826           cik->as_instance_klass()->has_finalizer()) {
 827         es = PointsToNode::GlobalEscape;
 828       }
 829     }
 830     add_java_object(call, es);
 831     PointsToNode* ptn = ptnode_adr(call_idx);
 832     if (!scalar_replaceable && ptn->scalar_replaceable()) {
 833       ptn->set_scalar_replaceable(false);
 834     }
 835   } else if (call->is_CallStaticJava()) {
 836     // Call nodes could be different types:
 837     //
 838     // 1. CallDynamicJavaNode (what happened during call is unknown):
 839     //
 840     //    - mapped to GlobalEscape JavaObject node if oop is returned;
 841     //
 842     //    - all oop arguments are escaping globally;
 843     //
 844     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
 845     //
 846     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
 847     //
 848     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
 849     //    - mapped to NoEscape JavaObject node if non-escaping object allocated
 850     //      during call is returned;
 851     //    - mapped to ArgEscape LocalVar node pointed to object arguments
 852     //      which are returned and does not escape during call;
 853     //
 854     //    - oop arguments escaping status is defined by bytecode analysis;
 855     //
 856     // For a static call, we know exactly what method is being called.
 857     // Use bytecode estimator to record whether the call's return value escapes.
 858     ciMethod* meth = call->as_CallJava()->method();
 859     if (meth == NULL) {
 860       const char* name = call->as_CallStaticJava()->_name;
 861       assert(strncmp(name, "_multianewarray", 15) == 0, "TODO: add failed case check");
 862       // Returns a newly allocated unescaped object.
 863       add_java_object(call, PointsToNode::NoEscape);
 864       ptnode_adr(call_idx)->set_scalar_replaceable(false);
 865     } else if (meth->is_boxing_method()) {
 866       // Returns boxing object
 867       PointsToNode::EscapeState es;
 868       vmIntrinsics::ID intr = meth->intrinsic_id();
 869       if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
 870         // It does not escape if object is always allocated.
 871         es = PointsToNode::NoEscape;
 872       } else {
 873         // It escapes globally if object could be loaded from cache.
 874         es = PointsToNode::GlobalEscape;
 875       }
 876       add_java_object(call, es);
 877     } else {
 878       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
 879       call_analyzer->copy_dependencies(_compile->dependencies());
 880       if (call_analyzer->is_return_allocated()) {
 881         // Returns a newly allocated unescaped object, simply
 882         // update dependency information.
 883         // Mark it as NoEscape so that objects referenced by
 884         // it's fields will be marked as NoEscape at least.
 885         add_java_object(call, PointsToNode::NoEscape);
 886         ptnode_adr(call_idx)->set_scalar_replaceable(false);
 887       } else {
 888         // Determine whether any arguments are returned.
 889         const TypeTuple* d = call->tf()->domain();
 890         bool ret_arg = false;
 891         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 892           if (d->field_at(i)->isa_ptr() != NULL &&
 893               call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
 894             ret_arg = true;
 895             break;
 896           }
 897         }
 898         if (ret_arg) {
 899           add_local_var(call, PointsToNode::ArgEscape);
 900         } else {
 901           // Returns unknown object.
 902           map_ideal_node(call, phantom_obj);
 903         }
 904       }
 905     }
 906   } else {
 907     // An other type of call, assume the worst case:
 908     // returned value is unknown and globally escapes.
 909     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
 910     map_ideal_node(call, phantom_obj);
 911   }
 912 }
 913 
 914 void ConnectionGraph::process_call_arguments(CallNode *call) {
 915     bool is_arraycopy = false;
 916     switch (call->Opcode()) {
 917 #ifdef ASSERT
 918     case Op_Allocate:
 919     case Op_AllocateArray:
 920     case Op_Lock:
 921     case Op_Unlock:
 922       assert(false, "should be done already");
 923       break;
 924 #endif
 925     case Op_ArrayCopy:
 926     case Op_CallLeafNoFP:
 927       // Most array copies are ArrayCopy nodes at this point but there
 928       // are still a few direct calls to the copy subroutines (See
 929       // PhaseStringOpts::copy_string())
 930       is_arraycopy = (call->Opcode() == Op_ArrayCopy) ||
 931         call->as_CallLeaf()->is_call_to_arraycopystub();
 932       // fall through
 933     case Op_CallLeaf: {
 934       // Stub calls, objects do not escape but they are not scale replaceable.
 935       // Adjust escape state for outgoing arguments.
 936       const TypeTuple * d = call->tf()->domain();
 937       bool src_has_oops = false;
 938       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 939         const Type* at = d->field_at(i);
 940         Node *arg = call->in(i);
 941         if (arg == NULL) {
 942           continue;
 943         }
 944         const Type *aat = _igvn->type(arg);
 945         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr())
 946           continue;
 947         if (arg->is_AddP()) {
 948           //
 949           // The inline_native_clone() case when the arraycopy stub is called
 950           // after the allocation before Initialize and CheckCastPP nodes.
 951           // Or normal arraycopy for object arrays case.
 952           //
 953           // Set AddP's base (Allocate) as not scalar replaceable since
 954           // pointer to the base (with offset) is passed as argument.
 955           //
 956           arg = get_addp_base(arg);
 957         }
 958         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
 959         assert(arg_ptn != NULL, "should be registered");
 960         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
 961         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
 962           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
 963                  aat->isa_ptr() != NULL, "expecting an Ptr");
 964           bool arg_has_oops = aat->isa_oopptr() &&
 965                               (aat->isa_oopptr()->klass() == NULL || aat->isa_instptr() ||
 966                                (aat->isa_aryptr() && aat->isa_aryptr()->klass()->is_obj_array_klass()));
 967           if (i == TypeFunc::Parms) {
 968             src_has_oops = arg_has_oops;
 969           }
 970           //
 971           // src or dst could be j.l.Object when other is basic type array:
 972           //
 973           //   arraycopy(char[],0,Object*,0,size);
 974           //   arraycopy(Object*,0,char[],0,size);
 975           //
 976           // Don't add edges in such cases.
 977           //
 978           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
 979                                        arg_has_oops && (i > TypeFunc::Parms);
 980 #ifdef ASSERT
 981           if (!(is_arraycopy ||
 982                 BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(call) ||
 983                 (call->as_CallLeaf()->_name != NULL &&
 984                  (strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
 985                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32C") == 0 ||
 986                   strcmp(call->as_CallLeaf()->_name, "updateBytesAdler32") == 0 ||
 987                   strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
 988                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
 989                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
 990                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
 991                   strcmp(call->as_CallLeaf()->_name, "electronicCodeBook_encryptAESCrypt") == 0 ||
 992                   strcmp(call->as_CallLeaf()->_name, "electronicCodeBook_decryptAESCrypt") == 0 ||
 993                   strcmp(call->as_CallLeaf()->_name, "counterMode_AESCrypt") == 0 ||
 994                   strcmp(call->as_CallLeaf()->_name, "ghash_processBlocks") == 0 ||
 995                   strcmp(call->as_CallLeaf()->_name, "encodeBlock") == 0 ||
 996                   strcmp(call->as_CallLeaf()->_name, "md5_implCompress") == 0 ||
 997                   strcmp(call->as_CallLeaf()->_name, "md5_implCompressMB") == 0 ||
 998                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
 999                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
1000                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
1001                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
1002                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
1003                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
1004                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
1005                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
1006                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0 ||
1007                   strcmp(call->as_CallLeaf()->_name, "montgomery_multiply") == 0 ||
1008                   strcmp(call->as_CallLeaf()->_name, "montgomery_square") == 0 ||
1009                   strcmp(call->as_CallLeaf()->_name, "bigIntegerRightShiftWorker") == 0 ||
1010                   strcmp(call->as_CallLeaf()->_name, "bigIntegerLeftShiftWorker") == 0 ||
1011                   strcmp(call->as_CallLeaf()->_name, "vectorizedMismatch") == 0 ||
1012                   strcmp(call->as_CallLeaf()->_name, "get_referenced_objects") == 0)
1013                  ))) {
1014             call->dump();
1015             fatal("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name);
1016           }
1017 #endif
1018           // Always process arraycopy's destination object since
1019           // we need to add all possible edges to references in
1020           // source object.
1021           if (arg_esc >= PointsToNode::ArgEscape &&
1022               !arg_is_arraycopy_dest) {
1023             continue;
1024           }
1025           PointsToNode::EscapeState es = PointsToNode::ArgEscape;
1026           if (call->is_ArrayCopy()) {
1027             ArrayCopyNode* ac = call->as_ArrayCopy();
1028             if (ac->is_clonebasic() ||
1029                 ac->is_arraycopy_validated() ||
1030                 ac->is_copyof_validated() ||
1031                 ac->is_copyofrange_validated()) {
1032               es = PointsToNode::NoEscape;
1033             }
1034           }
1035           set_escape_state(arg_ptn, es);
1036           if (arg_is_arraycopy_dest) {
1037             Node* src = call->in(TypeFunc::Parms);
1038             if (src->is_AddP()) {
1039               src = get_addp_base(src);
1040             }
1041             PointsToNode* src_ptn = ptnode_adr(src->_idx);
1042             assert(src_ptn != NULL, "should be registered");
1043             if (arg_ptn != src_ptn) {
1044               // Special arraycopy edge:
1045               // A destination object's field can't have the source object
1046               // as base since objects escape states are not related.
1047               // Only escape state of destination object's fields affects
1048               // escape state of fields in source object.
1049               add_arraycopy(call, es, src_ptn, arg_ptn);
1050             }
1051           }
1052         }
1053       }
1054       break;
1055     }
1056     case Op_CallStaticJava: {
1057       // For a static call, we know exactly what method is being called.
1058       // Use bytecode estimator to record the call's escape affects
1059 #ifdef ASSERT
1060       const char* name = call->as_CallStaticJava()->_name;
1061       assert((name == NULL || strcmp(name, "uncommon_trap") != 0), "normal calls only");
1062 #endif
1063       ciMethod* meth = call->as_CallJava()->method();
1064       if ((meth != NULL) && meth->is_boxing_method()) {
1065         break; // Boxing methods do not modify any oops.
1066       }
1067       BCEscapeAnalyzer* call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
1068       // fall-through if not a Java method or no analyzer information
1069       if (call_analyzer != NULL) {
1070         PointsToNode* call_ptn = ptnode_adr(call->_idx);
1071         const TypeTuple* d = call->tf()->domain();
1072         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1073           const Type* at = d->field_at(i);
1074           int k = i - TypeFunc::Parms;
1075           Node* arg = call->in(i);
1076           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
1077           if (at->isa_ptr() != NULL &&
1078               call_analyzer->is_arg_returned(k)) {
1079             // The call returns arguments.
1080             if (call_ptn != NULL) { // Is call's result used?
1081               assert(call_ptn->is_LocalVar(), "node should be registered");
1082               assert(arg_ptn != NULL, "node should be registered");
1083               add_edge(call_ptn, arg_ptn);
1084             }
1085           }
1086           if (at->isa_oopptr() != NULL &&
1087               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
1088             if (!call_analyzer->is_arg_stack(k)) {
1089               // The argument global escapes
1090               set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1091             } else {
1092               set_escape_state(arg_ptn, PointsToNode::ArgEscape);
1093               if (!call_analyzer->is_arg_local(k)) {
1094                 // The argument itself doesn't escape, but any fields might
1095                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1096               }
1097             }
1098           }
1099         }
1100         if (call_ptn != NULL && call_ptn->is_LocalVar()) {
1101           // The call returns arguments.
1102           assert(call_ptn->edge_count() > 0, "sanity");
1103           if (!call_analyzer->is_return_local()) {
1104             // Returns also unknown object.
1105             add_edge(call_ptn, phantom_obj);
1106           }
1107         }
1108         break;
1109       }
1110     }
1111     default: {
1112       // Fall-through here if not a Java method or no analyzer information
1113       // or some other type of call, assume the worst case: all arguments
1114       // globally escape.
1115       const TypeTuple* d = call->tf()->domain();
1116       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1117         const Type* at = d->field_at(i);
1118         if (at->isa_oopptr() != NULL) {
1119           Node* arg = call->in(i);
1120           if (arg->is_AddP()) {
1121             arg = get_addp_base(arg);
1122           }
1123           assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
1124           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
1125         }
1126       }
1127     }
1128   }
1129 }
1130 
1131 
1132 // Finish Graph construction.
1133 bool ConnectionGraph::complete_connection_graph(
1134                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1135                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1136                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1137                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
1138   // Normally only 1-3 passes needed to build Connection Graph depending
1139   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
1140   // Set limit to 20 to catch situation when something did go wrong and
1141   // bailout Escape Analysis.
1142   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
1143 #define CG_BUILD_ITER_LIMIT 20
1144 
1145   // Propagate GlobalEscape and ArgEscape escape states and check that
1146   // we still have non-escaping objects. The method pushs on _worklist
1147   // Field nodes which reference phantom_object.
1148   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1149     return false; // Nothing to do.
1150   }
1151   // Now propagate references to all JavaObject nodes.
1152   int java_objects_length = java_objects_worklist.length();
1153   elapsedTimer time;
1154   bool timeout = false;
1155   int new_edges = 1;
1156   int iterations = 0;
1157   do {
1158     while ((new_edges > 0) &&
1159            (iterations++ < CG_BUILD_ITER_LIMIT)) {
1160       double start_time = time.seconds();
1161       time.start();
1162       new_edges = 0;
1163       // Propagate references to phantom_object for nodes pushed on _worklist
1164       // by find_non_escaped_objects() and find_field_value().
1165       new_edges += add_java_object_edges(phantom_obj, false);
1166       for (int next = 0; next < java_objects_length; ++next) {
1167         JavaObjectNode* ptn = java_objects_worklist.at(next);
1168         new_edges += add_java_object_edges(ptn, true);
1169 
1170 #define SAMPLE_SIZE 4
1171         if ((next % SAMPLE_SIZE) == 0) {
1172           // Each 4 iterations calculate how much time it will take
1173           // to complete graph construction.
1174           time.stop();
1175           // Poll for requests from shutdown mechanism to quiesce compiler
1176           // because Connection graph construction may take long time.
1177           CompileBroker::maybe_block();
1178           double stop_time = time.seconds();
1179           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
1180           double time_until_end = time_per_iter * (double)(java_objects_length - next);
1181           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
1182             timeout = true;
1183             break; // Timeout
1184           }
1185           start_time = stop_time;
1186           time.start();
1187         }
1188 #undef SAMPLE_SIZE
1189 
1190       }
1191       if (timeout) break;
1192       if (new_edges > 0) {
1193         // Update escape states on each iteration if graph was updated.
1194         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1195           return false; // Nothing to do.
1196         }
1197       }
1198       time.stop();
1199       if (time.seconds() >= EscapeAnalysisTimeout) {
1200         timeout = true;
1201         break;
1202       }
1203     }
1204     if ((iterations < CG_BUILD_ITER_LIMIT) && !timeout) {
1205       time.start();
1206       // Find fields which have unknown value.
1207       int fields_length = oop_fields_worklist.length();
1208       for (int next = 0; next < fields_length; next++) {
1209         FieldNode* field = oop_fields_worklist.at(next);
1210         if (field->edge_count() == 0) {
1211           new_edges += find_field_value(field);
1212           // This code may added new edges to phantom_object.
1213           // Need an other cycle to propagate references to phantom_object.
1214         }
1215       }
1216       time.stop();
1217       if (time.seconds() >= EscapeAnalysisTimeout) {
1218         timeout = true;
1219         break;
1220       }
1221     } else {
1222       new_edges = 0; // Bailout
1223     }
1224   } while (new_edges > 0);
1225 
1226   // Bailout if passed limits.
1227   if ((iterations >= CG_BUILD_ITER_LIMIT) || timeout) {
1228     Compile* C = _compile;
1229     if (C->log() != NULL) {
1230       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
1231       C->log()->text("%s", timeout ? "time" : "iterations");
1232       C->log()->end_elem(" limit'");
1233     }
1234     assert(ExitEscapeAnalysisOnTimeout, "infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
1235            time.seconds(), iterations, nodes_size(), ptnodes_worklist.length());
1236     // Possible infinite build_connection_graph loop,
1237     // bailout (no changes to ideal graph were made).
1238     return false;
1239   }
1240 #ifdef ASSERT
1241   if (Verbose && PrintEscapeAnalysis) {
1242     tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
1243                   iterations, nodes_size(), ptnodes_worklist.length());
1244   }
1245 #endif
1246 
1247 #undef CG_BUILD_ITER_LIMIT
1248 
1249   // Find fields initialized by NULL for non-escaping Allocations.
1250   int non_escaped_length = non_escaped_worklist.length();
1251   for (int next = 0; next < non_escaped_length; next++) {
1252     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1253     PointsToNode::EscapeState es = ptn->escape_state();
1254     assert(es <= PointsToNode::ArgEscape, "sanity");
1255     if (es == PointsToNode::NoEscape) {
1256       if (find_init_values(ptn, null_obj, _igvn) > 0) {
1257         // Adding references to NULL object does not change escape states
1258         // since it does not escape. Also no fields are added to NULL object.
1259         add_java_object_edges(null_obj, false);
1260       }
1261     }
1262     Node* n = ptn->ideal_node();
1263     if (n->is_Allocate()) {
1264       // The object allocated by this Allocate node will never be
1265       // seen by an other thread. Mark it so that when it is
1266       // expanded no MemBarStoreStore is added.
1267       InitializeNode* ini = n->as_Allocate()->initialization();
1268       if (ini != NULL)
1269         ini->set_does_not_escape();
1270     }
1271   }
1272   return true; // Finished graph construction.
1273 }
1274 
1275 // Propagate GlobalEscape and ArgEscape escape states to all nodes
1276 // and check that we still have non-escaping java objects.
1277 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
1278                                                GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
1279   GrowableArray<PointsToNode*> escape_worklist;
1280   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
1281   int ptnodes_length = ptnodes_worklist.length();
1282   for (int next = 0; next < ptnodes_length; ++next) {
1283     PointsToNode* ptn = ptnodes_worklist.at(next);
1284     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
1285         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
1286       escape_worklist.push(ptn);
1287     }
1288   }
1289   // Set escape states to referenced nodes (edges list).
1290   while (escape_worklist.length() > 0) {
1291     PointsToNode* ptn = escape_worklist.pop();
1292     PointsToNode::EscapeState es  = ptn->escape_state();
1293     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
1294     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
1295         es >= PointsToNode::ArgEscape) {
1296       // GlobalEscape or ArgEscape state of field means it has unknown value.
1297       if (add_edge(ptn, phantom_obj)) {
1298         // New edge was added
1299         add_field_uses_to_worklist(ptn->as_Field());
1300       }
1301     }
1302     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1303       PointsToNode* e = i.get();
1304       if (e->is_Arraycopy()) {
1305         assert(ptn->arraycopy_dst(), "sanity");
1306         // Propagate only fields escape state through arraycopy edge.
1307         if (e->fields_escape_state() < field_es) {
1308           set_fields_escape_state(e, field_es);
1309           escape_worklist.push(e);
1310         }
1311       } else if (es >= field_es) {
1312         // fields_escape_state is also set to 'es' if it is less than 'es'.
1313         if (e->escape_state() < es) {
1314           set_escape_state(e, es);
1315           escape_worklist.push(e);
1316         }
1317       } else {
1318         // Propagate field escape state.
1319         bool es_changed = false;
1320         if (e->fields_escape_state() < field_es) {
1321           set_fields_escape_state(e, field_es);
1322           es_changed = true;
1323         }
1324         if ((e->escape_state() < field_es) &&
1325             e->is_Field() && ptn->is_JavaObject() &&
1326             e->as_Field()->is_oop()) {
1327           // Change escape state of referenced fields.
1328           set_escape_state(e, field_es);
1329           es_changed = true;
1330         } else if (e->escape_state() < es) {
1331           set_escape_state(e, es);
1332           es_changed = true;
1333         }
1334         if (es_changed) {
1335           escape_worklist.push(e);
1336         }
1337       }
1338     }
1339   }
1340   // Remove escaped objects from non_escaped list.
1341   for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
1342     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1343     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
1344       non_escaped_worklist.delete_at(next);
1345     }
1346     if (ptn->escape_state() == PointsToNode::NoEscape) {
1347       // Find fields in non-escaped allocations which have unknown value.
1348       find_init_values(ptn, phantom_obj, NULL);
1349     }
1350   }
1351   return (non_escaped_worklist.length() > 0);
1352 }
1353 
1354 // Add all references to JavaObject node by walking over all uses.
1355 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
1356   int new_edges = 0;
1357   if (populate_worklist) {
1358     // Populate _worklist by uses of jobj's uses.
1359     for (UseIterator i(jobj); i.has_next(); i.next()) {
1360       PointsToNode* use = i.get();
1361       if (use->is_Arraycopy())
1362         continue;
1363       add_uses_to_worklist(use);
1364       if (use->is_Field() && use->as_Field()->is_oop()) {
1365         // Put on worklist all field's uses (loads) and
1366         // related field nodes (same base and offset).
1367         add_field_uses_to_worklist(use->as_Field());
1368       }
1369     }
1370   }
1371   for (int l = 0; l < _worklist.length(); l++) {
1372     PointsToNode* use = _worklist.at(l);
1373     if (PointsToNode::is_base_use(use)) {
1374       // Add reference from jobj to field and from field to jobj (field's base).
1375       use = PointsToNode::get_use_node(use)->as_Field();
1376       if (add_base(use->as_Field(), jobj)) {
1377         new_edges++;
1378       }
1379       continue;
1380     }
1381     assert(!use->is_JavaObject(), "sanity");
1382     if (use->is_Arraycopy()) {
1383       if (jobj == null_obj) // NULL object does not have field edges
1384         continue;
1385       // Added edge from Arraycopy node to arraycopy's source java object
1386       if (add_edge(use, jobj)) {
1387         jobj->set_arraycopy_src();
1388         new_edges++;
1389       }
1390       // and stop here.
1391       continue;
1392     }
1393     if (!add_edge(use, jobj))
1394       continue; // No new edge added, there was such edge already.
1395     new_edges++;
1396     if (use->is_LocalVar()) {
1397       add_uses_to_worklist(use);
1398       if (use->arraycopy_dst()) {
1399         for (EdgeIterator i(use); i.has_next(); i.next()) {
1400           PointsToNode* e = i.get();
1401           if (e->is_Arraycopy()) {
1402             if (jobj == null_obj) // NULL object does not have field edges
1403               continue;
1404             // Add edge from arraycopy's destination java object to Arraycopy node.
1405             if (add_edge(jobj, e)) {
1406               new_edges++;
1407               jobj->set_arraycopy_dst();
1408             }
1409           }
1410         }
1411       }
1412     } else {
1413       // Added new edge to stored in field values.
1414       // Put on worklist all field's uses (loads) and
1415       // related field nodes (same base and offset).
1416       add_field_uses_to_worklist(use->as_Field());
1417     }
1418   }
1419   _worklist.clear();
1420   _in_worklist.reset();
1421   return new_edges;
1422 }
1423 
1424 // Put on worklist all related field nodes.
1425 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
1426   assert(field->is_oop(), "sanity");
1427   int offset = field->offset();
1428   add_uses_to_worklist(field);
1429   // Loop over all bases of this field and push on worklist Field nodes
1430   // with the same offset and base (since they may reference the same field).
1431   for (BaseIterator i(field); i.has_next(); i.next()) {
1432     PointsToNode* base = i.get();
1433     add_fields_to_worklist(field, base);
1434     // Check if the base was source object of arraycopy and go over arraycopy's
1435     // destination objects since values stored to a field of source object are
1436     // accessable by uses (loads) of fields of destination objects.
1437     if (base->arraycopy_src()) {
1438       for (UseIterator j(base); j.has_next(); j.next()) {
1439         PointsToNode* arycp = j.get();
1440         if (arycp->is_Arraycopy()) {
1441           for (UseIterator k(arycp); k.has_next(); k.next()) {
1442             PointsToNode* abase = k.get();
1443             if (abase->arraycopy_dst() && abase != base) {
1444               // Look for the same arraycopy reference.
1445               add_fields_to_worklist(field, abase);
1446             }
1447           }
1448         }
1449       }
1450     }
1451   }
1452 }
1453 
1454 // Put on worklist all related field nodes.
1455 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
1456   int offset = field->offset();
1457   if (base->is_LocalVar()) {
1458     for (UseIterator j(base); j.has_next(); j.next()) {
1459       PointsToNode* f = j.get();
1460       if (PointsToNode::is_base_use(f)) { // Field
1461         f = PointsToNode::get_use_node(f);
1462         if (f == field || !f->as_Field()->is_oop())
1463           continue;
1464         int offs = f->as_Field()->offset();
1465         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1466           add_to_worklist(f);
1467         }
1468       }
1469     }
1470   } else {
1471     assert(base->is_JavaObject(), "sanity");
1472     if (// Skip phantom_object since it is only used to indicate that
1473         // this field's content globally escapes.
1474         (base != phantom_obj) &&
1475         // NULL object node does not have fields.
1476         (base != null_obj)) {
1477       for (EdgeIterator i(base); i.has_next(); i.next()) {
1478         PointsToNode* f = i.get();
1479         // Skip arraycopy edge since store to destination object field
1480         // does not update value in source object field.
1481         if (f->is_Arraycopy()) {
1482           assert(base->arraycopy_dst(), "sanity");
1483           continue;
1484         }
1485         if (f == field || !f->as_Field()->is_oop())
1486           continue;
1487         int offs = f->as_Field()->offset();
1488         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1489           add_to_worklist(f);
1490         }
1491       }
1492     }
1493   }
1494 }
1495 
1496 // Find fields which have unknown value.
1497 int ConnectionGraph::find_field_value(FieldNode* field) {
1498   // Escaped fields should have init value already.
1499   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
1500   int new_edges = 0;
1501   for (BaseIterator i(field); i.has_next(); i.next()) {
1502     PointsToNode* base = i.get();
1503     if (base->is_JavaObject()) {
1504       // Skip Allocate's fields which will be processed later.
1505       if (base->ideal_node()->is_Allocate())
1506         return 0;
1507       assert(base == null_obj, "only NULL ptr base expected here");
1508     }
1509   }
1510   if (add_edge(field, phantom_obj)) {
1511     // New edge was added
1512     new_edges++;
1513     add_field_uses_to_worklist(field);
1514   }
1515   return new_edges;
1516 }
1517 
1518 // Find fields initializing values for allocations.
1519 int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
1520   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
1521   int new_edges = 0;
1522   Node* alloc = pta->ideal_node();
1523   if (init_val == phantom_obj) {
1524     // Do nothing for Allocate nodes since its fields values are
1525     // "known" unless they are initialized by arraycopy/clone.
1526     if (alloc->is_Allocate() && !pta->arraycopy_dst())
1527       return 0;
1528     assert(pta->arraycopy_dst() || alloc->as_CallStaticJava(), "sanity");
1529 #ifdef ASSERT
1530     if (!pta->arraycopy_dst() && alloc->as_CallStaticJava()->method() == NULL) {
1531       const char* name = alloc->as_CallStaticJava()->_name;
1532       assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
1533     }
1534 #endif
1535     // Non-escaped allocation returned from Java or runtime call have
1536     // unknown values in fields.
1537     for (EdgeIterator i(pta); i.has_next(); i.next()) {
1538       PointsToNode* field = i.get();
1539       if (field->is_Field() && field->as_Field()->is_oop()) {
1540         if (add_edge(field, phantom_obj)) {
1541           // New edge was added
1542           new_edges++;
1543           add_field_uses_to_worklist(field->as_Field());
1544         }
1545       }
1546     }
1547     return new_edges;
1548   }
1549   assert(init_val == null_obj, "sanity");
1550   // Do nothing for Call nodes since its fields values are unknown.
1551   if (!alloc->is_Allocate())
1552     return 0;
1553 
1554   InitializeNode* ini = alloc->as_Allocate()->initialization();
1555   bool visited_bottom_offset = false;
1556   GrowableArray<int> offsets_worklist;
1557 
1558   // Check if an oop field's initializing value is recorded and add
1559   // a corresponding NULL if field's value if it is not recorded.
1560   // Connection Graph does not record a default initialization by NULL
1561   // captured by Initialize node.
1562   //
1563   for (EdgeIterator i(pta); i.has_next(); i.next()) {
1564     PointsToNode* field = i.get(); // Field (AddP)
1565     if (!field->is_Field() || !field->as_Field()->is_oop())
1566       continue; // Not oop field
1567     int offset = field->as_Field()->offset();
1568     if (offset == Type::OffsetBot) {
1569       if (!visited_bottom_offset) {
1570         // OffsetBot is used to reference array's element,
1571         // always add reference to NULL to all Field nodes since we don't
1572         // known which element is referenced.
1573         if (add_edge(field, null_obj)) {
1574           // New edge was added
1575           new_edges++;
1576           add_field_uses_to_worklist(field->as_Field());
1577           visited_bottom_offset = true;
1578         }
1579       }
1580     } else {
1581       // Check only oop fields.
1582       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
1583       if (adr_type->isa_rawptr()) {
1584 #ifdef ASSERT
1585         // Raw pointers are used for initializing stores so skip it
1586         // since it should be recorded already
1587         Node* base = get_addp_base(field->ideal_node());
1588         assert(adr_type->isa_rawptr() && is_captured_store_address(field->ideal_node()), "unexpected pointer type");
1589 #endif
1590         continue;
1591       }
1592       if (!offsets_worklist.contains(offset)) {
1593         offsets_worklist.append(offset);
1594         Node* value = NULL;
1595         if (ini != NULL) {
1596           // StoreP::memory_type() == T_ADDRESS
1597           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
1598           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
1599           // Make sure initializing store has the same type as this AddP.
1600           // This AddP may reference non existing field because it is on a
1601           // dead branch of bimorphic call which is not eliminated yet.
1602           if (store != NULL && store->is_Store() &&
1603               store->as_Store()->memory_type() == ft) {
1604             value = store->in(MemNode::ValueIn);
1605 #ifdef ASSERT
1606             if (VerifyConnectionGraph) {
1607               // Verify that AddP already points to all objects the value points to.
1608               PointsToNode* val = ptnode_adr(value->_idx);
1609               assert((val != NULL), "should be processed already");
1610               PointsToNode* missed_obj = NULL;
1611               if (val->is_JavaObject()) {
1612                 if (!field->points_to(val->as_JavaObject())) {
1613                   missed_obj = val;
1614                 }
1615               } else {
1616                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
1617                   tty->print_cr("----------init store has invalid value -----");
1618                   store->dump();
1619                   val->dump();
1620                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
1621                 }
1622                 for (EdgeIterator j(val); j.has_next(); j.next()) {
1623                   PointsToNode* obj = j.get();
1624                   if (obj->is_JavaObject()) {
1625                     if (!field->points_to(obj->as_JavaObject())) {
1626                       missed_obj = obj;
1627                       break;
1628                     }
1629                   }
1630                 }
1631               }
1632               if (missed_obj != NULL) {
1633                 tty->print_cr("----------field---------------------------------");
1634                 field->dump();
1635                 tty->print_cr("----------missed referernce to object-----------");
1636                 missed_obj->dump();
1637                 tty->print_cr("----------object referernced by init store -----");
1638                 store->dump();
1639                 val->dump();
1640                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
1641               }
1642             }
1643 #endif
1644           } else {
1645             // There could be initializing stores which follow allocation.
1646             // For example, a volatile field store is not collected
1647             // by Initialize node.
1648             //
1649             // Need to check for dependent loads to separate such stores from
1650             // stores which follow loads. For now, add initial value NULL so
1651             // that compare pointers optimization works correctly.
1652           }
1653         }
1654         if (value == NULL) {
1655           // A field's initializing value was not recorded. Add NULL.
1656           if (add_edge(field, null_obj)) {
1657             // New edge was added
1658             new_edges++;
1659             add_field_uses_to_worklist(field->as_Field());
1660           }
1661         }
1662       }
1663     }
1664   }
1665   return new_edges;
1666 }
1667 
1668 // Adjust scalar_replaceable state after Connection Graph is built.
1669 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
1670   // Search for non-escaping objects which are not scalar replaceable
1671   // and mark them to propagate the state to referenced objects.
1672 
1673   // 1. An object is not scalar replaceable if the field into which it is
1674   // stored has unknown offset (stored into unknown element of an array).
1675   //
1676   for (UseIterator i(jobj); i.has_next(); i.next()) {
1677     PointsToNode* use = i.get();
1678     if (use->is_Arraycopy()) {
1679       continue;
1680     }
1681     if (use->is_Field()) {
1682       FieldNode* field = use->as_Field();
1683       assert(field->is_oop() && field->scalar_replaceable(), "sanity");
1684       if (field->offset() == Type::OffsetBot) {
1685         jobj->set_scalar_replaceable(false);
1686         return;
1687       }
1688       // 2. An object is not scalar replaceable if the field into which it is
1689       // stored has multiple bases one of which is null.
1690       if (field->base_count() > 1) {
1691         for (BaseIterator i(field); i.has_next(); i.next()) {
1692           PointsToNode* base = i.get();
1693           if (base == null_obj) {
1694             jobj->set_scalar_replaceable(false);
1695             return;
1696           }
1697         }
1698       }
1699     }
1700     assert(use->is_Field() || use->is_LocalVar(), "sanity");
1701     // 3. An object is not scalar replaceable if it is merged with other objects.
1702     for (EdgeIterator j(use); j.has_next(); j.next()) {
1703       PointsToNode* ptn = j.get();
1704       if (ptn->is_JavaObject() && ptn != jobj) {
1705         // Mark all objects.
1706         jobj->set_scalar_replaceable(false);
1707          ptn->set_scalar_replaceable(false);
1708       }
1709     }
1710     if (!jobj->scalar_replaceable()) {
1711       return;
1712     }
1713   }
1714 
1715   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
1716     if (j.get()->is_Arraycopy()) {
1717       continue;
1718     }
1719 
1720     // Non-escaping object node should point only to field nodes.
1721     FieldNode* field = j.get()->as_Field();
1722     int offset = field->as_Field()->offset();
1723 
1724     // 4. An object is not scalar replaceable if it has a field with unknown
1725     // offset (array's element is accessed in loop).
1726     if (offset == Type::OffsetBot) {
1727       jobj->set_scalar_replaceable(false);
1728       return;
1729     }
1730     // 5. Currently an object is not scalar replaceable if a LoadStore node
1731     // access its field since the field value is unknown after it.
1732     //
1733     Node* n = field->ideal_node();
1734 
1735     // Test for an unsafe access that was parsed as maybe off heap
1736     // (with a CheckCastPP to raw memory).
1737     assert(n->is_AddP(), "expect an address computation");
1738     if (n->in(AddPNode::Base)->is_top() &&
1739         n->in(AddPNode::Address)->Opcode() == Op_CheckCastPP) {
1740       assert(n->in(AddPNode::Address)->bottom_type()->isa_rawptr(), "raw address so raw cast expected");
1741       assert(_igvn->type(n->in(AddPNode::Address)->in(1))->isa_oopptr(), "cast pattern at unsafe access expected");
1742       jobj->set_scalar_replaceable(false);
1743       return;
1744     }
1745 
1746     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1747       Node* u = n->fast_out(i);
1748       if (u->is_LoadStore() || (u->is_Mem() && u->as_Mem()->is_mismatched_access())) {
1749         jobj->set_scalar_replaceable(false);
1750         return;
1751       }
1752     }
1753 
1754     // 6. Or the address may point to more then one object. This may produce
1755     // the false positive result (set not scalar replaceable)
1756     // since the flow-insensitive escape analysis can't separate
1757     // the case when stores overwrite the field's value from the case
1758     // when stores happened on different control branches.
1759     //
1760     // Note: it will disable scalar replacement in some cases:
1761     //
1762     //    Point p[] = new Point[1];
1763     //    p[0] = new Point(); // Will be not scalar replaced
1764     //
1765     // but it will save us from incorrect optimizations in next cases:
1766     //
1767     //    Point p[] = new Point[1];
1768     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
1769     //
1770     if (field->base_count() > 1) {
1771       for (BaseIterator i(field); i.has_next(); i.next()) {
1772         PointsToNode* base = i.get();
1773         // Don't take into account LocalVar nodes which
1774         // may point to only one object which should be also
1775         // this field's base by now.
1776         if (base->is_JavaObject() && base != jobj) {
1777           // Mark all bases.
1778           jobj->set_scalar_replaceable(false);
1779           base->set_scalar_replaceable(false);
1780         }
1781       }
1782     }
1783   }
1784 }
1785 
1786 #ifdef ASSERT
1787 void ConnectionGraph::verify_connection_graph(
1788                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1789                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1790                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1791                          GrowableArray<Node*>& addp_worklist) {
1792   // Verify that graph is complete - no new edges could be added.
1793   int java_objects_length = java_objects_worklist.length();
1794   int non_escaped_length  = non_escaped_worklist.length();
1795   int new_edges = 0;
1796   for (int next = 0; next < java_objects_length; ++next) {
1797     JavaObjectNode* ptn = java_objects_worklist.at(next);
1798     new_edges += add_java_object_edges(ptn, true);
1799   }
1800   assert(new_edges == 0, "graph was not complete");
1801   // Verify that escape state is final.
1802   int length = non_escaped_worklist.length();
1803   find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
1804   assert((non_escaped_length == non_escaped_worklist.length()) &&
1805          (non_escaped_length == length) &&
1806          (_worklist.length() == 0), "escape state was not final");
1807 
1808   // Verify fields information.
1809   int addp_length = addp_worklist.length();
1810   for (int next = 0; next < addp_length; ++next ) {
1811     Node* n = addp_worklist.at(next);
1812     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
1813     if (field->is_oop()) {
1814       // Verify that field has all bases
1815       Node* base = get_addp_base(n);
1816       PointsToNode* ptn = ptnode_adr(base->_idx);
1817       if (ptn->is_JavaObject()) {
1818         assert(field->has_base(ptn->as_JavaObject()), "sanity");
1819       } else {
1820         assert(ptn->is_LocalVar(), "sanity");
1821         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1822           PointsToNode* e = i.get();
1823           if (e->is_JavaObject()) {
1824             assert(field->has_base(e->as_JavaObject()), "sanity");
1825           }
1826         }
1827       }
1828       // Verify that all fields have initializing values.
1829       if (field->edge_count() == 0) {
1830         tty->print_cr("----------field does not have references----------");
1831         field->dump();
1832         for (BaseIterator i(field); i.has_next(); i.next()) {
1833           PointsToNode* base = i.get();
1834           tty->print_cr("----------field has next base---------------------");
1835           base->dump();
1836           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
1837             tty->print_cr("----------base has fields-------------------------");
1838             for (EdgeIterator j(base); j.has_next(); j.next()) {
1839               j.get()->dump();
1840             }
1841             tty->print_cr("----------base has references---------------------");
1842             for (UseIterator j(base); j.has_next(); j.next()) {
1843               j.get()->dump();
1844             }
1845           }
1846         }
1847         for (UseIterator i(field); i.has_next(); i.next()) {
1848           i.get()->dump();
1849         }
1850         assert(field->edge_count() > 0, "sanity");
1851       }
1852     }
1853   }
1854 }
1855 #endif
1856 
1857 // Optimize ideal graph.
1858 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
1859                                            GrowableArray<Node*>& storestore_worklist) {
1860   Compile* C = _compile;
1861   PhaseIterGVN* igvn = _igvn;
1862   if (EliminateLocks) {
1863     // Mark locks before changing ideal graph.
1864     int cnt = C->macro_count();
1865     for( int i=0; i < cnt; i++ ) {
1866       Node *n = C->macro_node(i);
1867       if (n->is_AbstractLock()) { // Lock and Unlock nodes
1868         AbstractLockNode* alock = n->as_AbstractLock();
1869         if (!alock->is_non_esc_obj()) {
1870           if (not_global_escape(alock->obj_node())) {
1871             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
1872             // The lock could be marked eliminated by lock coarsening
1873             // code during first IGVN before EA. Replace coarsened flag
1874             // to eliminate all associated locks/unlocks.
1875 #ifdef ASSERT
1876             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
1877 #endif
1878             alock->set_non_esc_obj();
1879           }
1880         }
1881       }
1882     }
1883   }
1884 
1885   if (OptimizePtrCompare) {
1886     // Add ConI(#CC_GT) and ConI(#CC_EQ).
1887     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);
1888     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
1889     // Optimize objects compare.
1890     while (ptr_cmp_worklist.length() != 0) {
1891       Node *n = ptr_cmp_worklist.pop();
1892       Node *res = optimize_ptr_compare(n);
1893       if (res != NULL) {
1894 #ifndef PRODUCT
1895         if (PrintOptimizePtrCompare) {
1896           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, (res == _pcmp_eq ? "EQ" : "NotEQ"));
1897           if (Verbose) {
1898             n->dump(1);
1899           }
1900         }
1901 #endif
1902         igvn->replace_node(n, res);
1903       }
1904     }
1905     // cleanup
1906     if (_pcmp_neq->outcnt() == 0)
1907       igvn->hash_delete(_pcmp_neq);
1908     if (_pcmp_eq->outcnt()  == 0)
1909       igvn->hash_delete(_pcmp_eq);
1910   }
1911 
1912   // For MemBarStoreStore nodes added in library_call.cpp, check
1913   // escape status of associated AllocateNode and optimize out
1914   // MemBarStoreStore node if the allocated object never escapes.
1915   while (storestore_worklist.length() != 0) {
1916     Node *n = storestore_worklist.pop();
1917     MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
1918     Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
1919     if (alloc->is_Allocate() && not_global_escape(alloc)) {
1920       MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
1921       mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
1922       mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
1923       igvn->register_new_node_with_optimizer(mb);
1924       igvn->replace_node(storestore, mb);
1925     }
1926   }
1927 }
1928 
1929 // Optimize objects compare.
1930 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
1931   assert(OptimizePtrCompare, "sanity");
1932   PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
1933   PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
1934   JavaObjectNode* jobj1 = unique_java_object(n->in(1));
1935   JavaObjectNode* jobj2 = unique_java_object(n->in(2));
1936   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
1937   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
1938 
1939   // Check simple cases first.
1940   if (jobj1 != NULL) {
1941     if (jobj1->escape_state() == PointsToNode::NoEscape) {
1942       if (jobj1 == jobj2) {
1943         // Comparing the same not escaping object.
1944         return _pcmp_eq;
1945       }
1946       Node* obj = jobj1->ideal_node();
1947       // Comparing not escaping allocation.
1948       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1949           !ptn2->points_to(jobj1)) {
1950         return _pcmp_neq; // This includes nullness check.
1951       }
1952     }
1953   }
1954   if (jobj2 != NULL) {
1955     if (jobj2->escape_state() == PointsToNode::NoEscape) {
1956       Node* obj = jobj2->ideal_node();
1957       // Comparing not escaping allocation.
1958       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1959           !ptn1->points_to(jobj2)) {
1960         return _pcmp_neq; // This includes nullness check.
1961       }
1962     }
1963   }
1964   if (jobj1 != NULL && jobj1 != phantom_obj &&
1965       jobj2 != NULL && jobj2 != phantom_obj &&
1966       jobj1->ideal_node()->is_Con() &&
1967       jobj2->ideal_node()->is_Con()) {
1968     // Klass or String constants compare. Need to be careful with
1969     // compressed pointers - compare types of ConN and ConP instead of nodes.
1970     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
1971     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
1972     if (t1->make_ptr() == t2->make_ptr()) {
1973       return _pcmp_eq;
1974     } else {
1975       return _pcmp_neq;
1976     }
1977   }
1978   if (ptn1->meet(ptn2)) {
1979     return NULL; // Sets are not disjoint
1980   }
1981 
1982   // Sets are disjoint.
1983   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
1984   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
1985   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
1986   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
1987   if ((set1_has_unknown_ptr && set2_has_null_ptr) ||
1988       (set2_has_unknown_ptr && set1_has_null_ptr)) {
1989     // Check nullness of unknown object.
1990     return NULL;
1991   }
1992 
1993   // Disjointness by itself is not sufficient since
1994   // alias analysis is not complete for escaped objects.
1995   // Disjoint sets are definitely unrelated only when
1996   // at least one set has only not escaping allocations.
1997   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
1998     if (ptn1->non_escaping_allocation()) {
1999       return _pcmp_neq;
2000     }
2001   }
2002   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
2003     if (ptn2->non_escaping_allocation()) {
2004       return _pcmp_neq;
2005     }
2006   }
2007   return NULL;
2008 }
2009 
2010 // Connection Graph constuction functions.
2011 
2012 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
2013   PointsToNode* ptadr = _nodes.at(n->_idx);
2014   if (ptadr != NULL) {
2015     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
2016     return;
2017   }
2018   Compile* C = _compile;
2019   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
2020   _nodes.at_put(n->_idx, ptadr);
2021 }
2022 
2023 void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
2024   PointsToNode* ptadr = _nodes.at(n->_idx);
2025   if (ptadr != NULL) {
2026     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
2027     return;
2028   }
2029   Compile* C = _compile;
2030   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
2031   _nodes.at_put(n->_idx, ptadr);
2032 }
2033 
2034 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
2035   PointsToNode* ptadr = _nodes.at(n->_idx);
2036   if (ptadr != NULL) {
2037     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
2038     return;
2039   }
2040   bool unsafe = false;
2041   bool is_oop = is_oop_field(n, offset, &unsafe);
2042   if (unsafe) {
2043     es = PointsToNode::GlobalEscape;
2044   }
2045   Compile* C = _compile;
2046   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
2047   _nodes.at_put(n->_idx, field);
2048 }
2049 
2050 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
2051                                     PointsToNode* src, PointsToNode* dst) {
2052   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
2053   assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
2054   PointsToNode* ptadr = _nodes.at(n->_idx);
2055   if (ptadr != NULL) {
2056     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
2057     return;
2058   }
2059   Compile* C = _compile;
2060   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
2061   _nodes.at_put(n->_idx, ptadr);
2062   // Add edge from arraycopy node to source object.
2063   (void)add_edge(ptadr, src);
2064   src->set_arraycopy_src();
2065   // Add edge from destination object to arraycopy node.
2066   (void)add_edge(dst, ptadr);
2067   dst->set_arraycopy_dst();
2068 }
2069 
2070 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
2071   const Type* adr_type = n->as_AddP()->bottom_type();
2072   BasicType bt = T_INT;
2073   if (offset == Type::OffsetBot) {
2074     // Check only oop fields.
2075     if (!adr_type->isa_aryptr() ||
2076         (adr_type->isa_aryptr()->klass() == NULL) ||
2077          adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
2078       // OffsetBot is used to reference array's element. Ignore first AddP.
2079       if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
2080         bt = T_OBJECT;
2081       }
2082     }
2083   } else if (offset != oopDesc::klass_offset_in_bytes()) {
2084     if (adr_type->isa_instptr()) {
2085       ciField* field = _compile->alias_type(adr_type->isa_instptr())->field();
2086       if (field != NULL) {
2087         bt = field->layout_type();
2088       } else {
2089         // Check for unsafe oop field access
2090         if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN) ||
2091             n->has_out_with(Op_GetAndSetP, Op_GetAndSetN, Op_CompareAndExchangeP, Op_CompareAndExchangeN) ||
2092             n->has_out_with(Op_CompareAndSwapP, Op_CompareAndSwapN, Op_WeakCompareAndSwapP, Op_WeakCompareAndSwapN) ||
2093             BarrierSet::barrier_set()->barrier_set_c2()->escape_has_out_with_unsafe_object(n)) {
2094           bt = T_OBJECT;
2095           (*unsafe) = true;
2096         }
2097       }
2098     } else if (adr_type->isa_aryptr()) {
2099       if (offset == arrayOopDesc::length_offset_in_bytes()) {
2100         // Ignore array length load.
2101       } else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
2102         // Ignore first AddP.
2103       } else {
2104         const Type* elemtype = adr_type->isa_aryptr()->elem();
2105         bt = elemtype->array_element_basic_type();
2106       }
2107     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
2108       // Allocation initialization, ThreadLocal field access, unsafe access
2109       if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN) ||
2110           n->has_out_with(Op_GetAndSetP, Op_GetAndSetN, Op_CompareAndExchangeP, Op_CompareAndExchangeN) ||
2111           n->has_out_with(Op_CompareAndSwapP, Op_CompareAndSwapN, Op_WeakCompareAndSwapP, Op_WeakCompareAndSwapN) ||
2112           BarrierSet::barrier_set()->barrier_set_c2()->escape_has_out_with_unsafe_object(n)) {
2113         bt = T_OBJECT;
2114       }
2115     }
2116   }
2117   // Note: T_NARROWOOP is not classed as a real reference type
2118   return (is_reference_type(bt) || bt == T_NARROWOOP);
2119 }
2120 
2121 // Returns unique pointed java object or NULL.
2122 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
2123   assert(!_collecting, "should not call when contructed graph");
2124   // If the node was created after the escape computation we can't answer.
2125   uint idx = n->_idx;
2126   if (idx >= nodes_size()) {
2127     return NULL;
2128   }
2129   PointsToNode* ptn = ptnode_adr(idx);
2130   if (ptn == NULL) {
2131     return NULL;
2132   }
2133   if (ptn->is_JavaObject()) {
2134     return ptn->as_JavaObject();
2135   }
2136   assert(ptn->is_LocalVar(), "sanity");
2137   // Check all java objects it points to.
2138   JavaObjectNode* jobj = NULL;
2139   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2140     PointsToNode* e = i.get();
2141     if (e->is_JavaObject()) {
2142       if (jobj == NULL) {
2143         jobj = e->as_JavaObject();
2144       } else if (jobj != e) {
2145         return NULL;
2146       }
2147     }
2148   }
2149   return jobj;
2150 }
2151 
2152 // Return true if this node points only to non-escaping allocations.
2153 bool PointsToNode::non_escaping_allocation() {
2154   if (is_JavaObject()) {
2155     Node* n = ideal_node();
2156     if (n->is_Allocate() || n->is_CallStaticJava()) {
2157       return (escape_state() == PointsToNode::NoEscape);
2158     } else {
2159       return false;
2160     }
2161   }
2162   assert(is_LocalVar(), "sanity");
2163   // Check all java objects it points to.
2164   for (EdgeIterator i(this); i.has_next(); i.next()) {
2165     PointsToNode* e = i.get();
2166     if (e->is_JavaObject()) {
2167       Node* n = e->ideal_node();
2168       if ((e->escape_state() != PointsToNode::NoEscape) ||
2169           !(n->is_Allocate() || n->is_CallStaticJava())) {
2170         return false;
2171       }
2172     }
2173   }
2174   return true;
2175 }
2176 
2177 // Return true if we know the node does not escape globally.
2178 bool ConnectionGraph::not_global_escape(Node *n) {
2179   assert(!_collecting, "should not call during graph construction");
2180   // If the node was created after the escape computation we can't answer.
2181   uint idx = n->_idx;
2182   if (idx >= nodes_size()) {
2183     return false;
2184   }
2185   PointsToNode* ptn = ptnode_adr(idx);
2186   if (ptn == NULL) {
2187     return false; // not in congraph (e.g. ConI)
2188   }
2189   PointsToNode::EscapeState es = ptn->escape_state();
2190   // If we have already computed a value, return it.
2191   if (es >= PointsToNode::GlobalEscape)
2192     return false;
2193   if (ptn->is_JavaObject()) {
2194     return true; // (es < PointsToNode::GlobalEscape);
2195   }
2196   assert(ptn->is_LocalVar(), "sanity");
2197   // Check all java objects it points to.
2198   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2199     if (i.get()->escape_state() >= PointsToNode::GlobalEscape)
2200       return false;
2201   }
2202   return true;
2203 }
2204 
2205 
2206 // Helper functions
2207 
2208 // Return true if this node points to specified node or nodes it points to.
2209 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
2210   if (is_JavaObject()) {
2211     return (this == ptn);
2212   }
2213   assert(is_LocalVar() || is_Field(), "sanity");
2214   for (EdgeIterator i(this); i.has_next(); i.next()) {
2215     if (i.get() == ptn)
2216       return true;
2217   }
2218   return false;
2219 }
2220 
2221 // Return true if one node points to an other.
2222 bool PointsToNode::meet(PointsToNode* ptn) {
2223   if (this == ptn) {
2224     return true;
2225   } else if (ptn->is_JavaObject()) {
2226     return this->points_to(ptn->as_JavaObject());
2227   } else if (this->is_JavaObject()) {
2228     return ptn->points_to(this->as_JavaObject());
2229   }
2230   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
2231   int ptn_count =  ptn->edge_count();
2232   for (EdgeIterator i(this); i.has_next(); i.next()) {
2233     PointsToNode* this_e = i.get();
2234     for (int j = 0; j < ptn_count; j++) {
2235       if (this_e == ptn->edge(j))
2236         return true;
2237     }
2238   }
2239   return false;
2240 }
2241 
2242 #ifdef ASSERT
2243 // Return true if bases point to this java object.
2244 bool FieldNode::has_base(JavaObjectNode* jobj) const {
2245   for (BaseIterator i(this); i.has_next(); i.next()) {
2246     if (i.get() == jobj)
2247       return true;
2248   }
2249   return false;
2250 }
2251 #endif
2252 
2253 bool ConnectionGraph::is_captured_store_address(Node* addp) {
2254   // Handle simple case first.
2255   assert(_igvn->type(addp)->isa_oopptr() == NULL, "should be raw access");
2256   if (addp->in(AddPNode::Address)->is_Proj() && addp->in(AddPNode::Address)->in(0)->is_Allocate()) {
2257     return true;
2258   } else if (addp->in(AddPNode::Address)->is_Phi()) {
2259     for (DUIterator_Fast imax, i = addp->fast_outs(imax); i < imax; i++) {
2260       Node* addp_use = addp->fast_out(i);
2261       if (addp_use->is_Store()) {
2262         for (DUIterator_Fast jmax, j = addp_use->fast_outs(jmax); j < jmax; j++) {
2263           if (addp_use->fast_out(j)->is_Initialize()) {
2264             return true;
2265           }
2266         }
2267       }
2268     }
2269   }
2270   return false;
2271 }
2272 
2273 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
2274   const Type *adr_type = phase->type(adr);
2275   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL && is_captured_store_address(adr)) {
2276     // We are computing a raw address for a store captured by an Initialize
2277     // compute an appropriate address type. AddP cases #3 and #5 (see below).
2278     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
2279     assert(offs != Type::OffsetBot ||
2280            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
2281            "offset must be a constant or it is initialization of array");
2282     return offs;
2283   }
2284   const TypePtr *t_ptr = adr_type->isa_ptr();
2285   assert(t_ptr != NULL, "must be a pointer type");
2286   return t_ptr->offset();
2287 }
2288 
2289 Node* ConnectionGraph::get_addp_base(Node *addp) {
2290   assert(addp->is_AddP(), "must be AddP");
2291   //
2292   // AddP cases for Base and Address inputs:
2293   // case #1. Direct object's field reference:
2294   //     Allocate
2295   //       |
2296   //     Proj #5 ( oop result )
2297   //       |
2298   //     CheckCastPP (cast to instance type)
2299   //      | |
2300   //     AddP  ( base == address )
2301   //
2302   // case #2. Indirect object's field reference:
2303   //      Phi
2304   //       |
2305   //     CastPP (cast to instance type)
2306   //      | |
2307   //     AddP  ( base == address )
2308   //
2309   // case #3. Raw object's field reference for Initialize node:
2310   //      Allocate
2311   //        |
2312   //      Proj #5 ( oop result )
2313   //  top   |
2314   //     \  |
2315   //     AddP  ( base == top )
2316   //
2317   // case #4. Array's element reference:
2318   //   {CheckCastPP | CastPP}
2319   //     |  | |
2320   //     |  AddP ( array's element offset )
2321   //     |  |
2322   //     AddP ( array's offset )
2323   //
2324   // case #5. Raw object's field reference for arraycopy stub call:
2325   //          The inline_native_clone() case when the arraycopy stub is called
2326   //          after the allocation before Initialize and CheckCastPP nodes.
2327   //      Allocate
2328   //        |
2329   //      Proj #5 ( oop result )
2330   //       | |
2331   //       AddP  ( base == address )
2332   //
2333   // case #6. Constant Pool, ThreadLocal, CastX2P or
2334   //          Raw object's field reference:
2335   //      {ConP, ThreadLocal, CastX2P, raw Load}
2336   //  top   |
2337   //     \  |
2338   //     AddP  ( base == top )
2339   //
2340   // case #7. Klass's field reference.
2341   //      LoadKlass
2342   //       | |
2343   //       AddP  ( base == address )
2344   //
2345   // case #8. narrow Klass's field reference.
2346   //      LoadNKlass
2347   //       |
2348   //      DecodeN
2349   //       | |
2350   //       AddP  ( base == address )
2351   //
2352   // case #9. Mixed unsafe access
2353   //    {instance}
2354   //        |
2355   //      CheckCastPP (raw)
2356   //  top   |
2357   //     \  |
2358   //     AddP  ( base == top )
2359   //
2360   Node *base = addp->in(AddPNode::Base);
2361   if (base->uncast()->is_top()) { // The AddP case #3 and #6 and #9.
2362     base = addp->in(AddPNode::Address);
2363     while (base->is_AddP()) {
2364       // Case #6 (unsafe access) may have several chained AddP nodes.
2365       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
2366       base = base->in(AddPNode::Address);
2367     }
2368     if (base->Opcode() == Op_CheckCastPP &&
2369         base->bottom_type()->isa_rawptr() &&
2370         _igvn->type(base->in(1))->isa_oopptr()) {
2371       base = base->in(1); // Case #9
2372     } else {
2373       Node* uncast_base = base->uncast();
2374       int opcode = uncast_base->Opcode();
2375       assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
2376              opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
2377              (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
2378              is_captured_store_address(addp), "sanity");
2379     }
2380   }
2381   return base;
2382 }
2383 
2384 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
2385   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
2386   Node* addp2 = addp->raw_out(0);
2387   if (addp->outcnt() == 1 && addp2->is_AddP() &&
2388       addp2->in(AddPNode::Base) == n &&
2389       addp2->in(AddPNode::Address) == addp) {
2390     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
2391     //
2392     // Find array's offset to push it on worklist first and
2393     // as result process an array's element offset first (pushed second)
2394     // to avoid CastPP for the array's offset.
2395     // Otherwise the inserted CastPP (LocalVar) will point to what
2396     // the AddP (Field) points to. Which would be wrong since
2397     // the algorithm expects the CastPP has the same point as
2398     // as AddP's base CheckCastPP (LocalVar).
2399     //
2400     //    ArrayAllocation
2401     //     |
2402     //    CheckCastPP
2403     //     |
2404     //    memProj (from ArrayAllocation CheckCastPP)
2405     //     |  ||
2406     //     |  ||   Int (element index)
2407     //     |  ||    |   ConI (log(element size))
2408     //     |  ||    |   /
2409     //     |  ||   LShift
2410     //     |  ||  /
2411     //     |  AddP (array's element offset)
2412     //     |  |
2413     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
2414     //     | / /
2415     //     AddP (array's offset)
2416     //      |
2417     //     Load/Store (memory operation on array's element)
2418     //
2419     return addp2;
2420   }
2421   return NULL;
2422 }
2423 
2424 //
2425 // Adjust the type and inputs of an AddP which computes the
2426 // address of a field of an instance
2427 //
2428 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
2429   PhaseGVN* igvn = _igvn;
2430   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
2431   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
2432   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
2433   if (t == NULL) {
2434     // We are computing a raw address for a store captured by an Initialize
2435     // compute an appropriate address type (cases #3 and #5).
2436     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
2437     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
2438     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
2439     assert(offs != Type::OffsetBot, "offset must be a constant");
2440     t = base_t->add_offset(offs)->is_oopptr();
2441   }
2442   int inst_id =  base_t->instance_id();
2443   assert(!t->is_known_instance() || t->instance_id() == inst_id,
2444                              "old type must be non-instance or match new type");
2445 
2446   // The type 't' could be subclass of 'base_t'.
2447   // As result t->offset() could be large then base_t's size and it will
2448   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
2449   // constructor verifies correctness of the offset.
2450   //
2451   // It could happened on subclass's branch (from the type profiling
2452   // inlining) which was not eliminated during parsing since the exactness
2453   // of the allocation type was not propagated to the subclass type check.
2454   //
2455   // Or the type 't' could be not related to 'base_t' at all.
2456   // It could happened when CHA type is different from MDO type on a dead path
2457   // (for example, from instanceof check) which is not collapsed during parsing.
2458   //
2459   // Do nothing for such AddP node and don't process its users since
2460   // this code branch will go away.
2461   //
2462   if (!t->is_known_instance() &&
2463       !base_t->klass()->is_subtype_of(t->klass())) {
2464      return false; // bail out
2465   }
2466   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
2467   // Do NOT remove the next line: ensure a new alias index is allocated
2468   // for the instance type. Note: C++ will not remove it since the call
2469   // has side effect.
2470   int alias_idx = _compile->get_alias_index(tinst);
2471   igvn->set_type(addp, tinst);
2472   // record the allocation in the node map
2473   set_map(addp, get_map(base->_idx));
2474   // Set addp's Base and Address to 'base'.
2475   Node *abase = addp->in(AddPNode::Base);
2476   Node *adr   = addp->in(AddPNode::Address);
2477   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
2478       adr->in(0)->_idx == (uint)inst_id) {
2479     // Skip AddP cases #3 and #5.
2480   } else {
2481     assert(!abase->is_top(), "sanity"); // AddP case #3
2482     if (abase != base) {
2483       igvn->hash_delete(addp);
2484       addp->set_req(AddPNode::Base, base);
2485       if (abase == adr) {
2486         addp->set_req(AddPNode::Address, base);
2487       } else {
2488         // AddP case #4 (adr is array's element offset AddP node)
2489 #ifdef ASSERT
2490         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
2491         assert(adr->is_AddP() && atype != NULL &&
2492                atype->instance_id() == inst_id, "array's element offset should be processed first");
2493 #endif
2494       }
2495       igvn->hash_insert(addp);
2496     }
2497   }
2498   // Put on IGVN worklist since at least addp's type was changed above.
2499   record_for_optimizer(addp);
2500   return true;
2501 }
2502 
2503 //
2504 // Create a new version of orig_phi if necessary. Returns either the newly
2505 // created phi or an existing phi.  Sets create_new to indicate whether a new
2506 // phi was created.  Cache the last newly created phi in the node map.
2507 //
2508 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
2509   Compile *C = _compile;
2510   PhaseGVN* igvn = _igvn;
2511   new_created = false;
2512   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
2513   // nothing to do if orig_phi is bottom memory or matches alias_idx
2514   if (phi_alias_idx == alias_idx) {
2515     return orig_phi;
2516   }
2517   // Have we recently created a Phi for this alias index?
2518   PhiNode *result = get_map_phi(orig_phi->_idx);
2519   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
2520     return result;
2521   }
2522   // Previous check may fail when the same wide memory Phi was split into Phis
2523   // for different memory slices. Search all Phis for this region.
2524   if (result != NULL) {
2525     Node* region = orig_phi->in(0);
2526     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
2527       Node* phi = region->fast_out(i);
2528       if (phi->is_Phi() &&
2529           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
2530         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
2531         return phi->as_Phi();
2532       }
2533     }
2534   }
2535   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
2536     if (C->do_escape_analysis() == true && !C->failing()) {
2537       // Retry compilation without escape analysis.
2538       // If this is the first failure, the sentinel string will "stick"
2539       // to the Compile object, and the C2Compiler will see it and retry.
2540       C->record_failure(C2Compiler::retry_no_escape_analysis());
2541     }
2542     return NULL;
2543   }
2544   orig_phi_worklist.append_if_missing(orig_phi);
2545   const TypePtr *atype = C->get_adr_type(alias_idx);
2546   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
2547   C->copy_node_notes_to(result, orig_phi);
2548   igvn->set_type(result, result->bottom_type());
2549   record_for_optimizer(result);
2550   set_map(orig_phi, result);
2551   new_created = true;
2552   return result;
2553 }
2554 
2555 //
2556 // Return a new version of Memory Phi "orig_phi" with the inputs having the
2557 // specified alias index.
2558 //
2559 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist) {
2560   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
2561   Compile *C = _compile;
2562   PhaseGVN* igvn = _igvn;
2563   bool new_phi_created;
2564   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
2565   if (!new_phi_created) {
2566     return result;
2567   }
2568   GrowableArray<PhiNode *>  phi_list;
2569   GrowableArray<uint>  cur_input;
2570   PhiNode *phi = orig_phi;
2571   uint idx = 1;
2572   bool finished = false;
2573   while(!finished) {
2574     while (idx < phi->req()) {
2575       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist);
2576       if (mem != NULL && mem->is_Phi()) {
2577         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
2578         if (new_phi_created) {
2579           // found an phi for which we created a new split, push current one on worklist and begin
2580           // processing new one
2581           phi_list.push(phi);
2582           cur_input.push(idx);
2583           phi = mem->as_Phi();
2584           result = newphi;
2585           idx = 1;
2586           continue;
2587         } else {
2588           mem = newphi;
2589         }
2590       }
2591       if (C->failing()) {
2592         return NULL;
2593       }
2594       result->set_req(idx++, mem);
2595     }
2596 #ifdef ASSERT
2597     // verify that the new Phi has an input for each input of the original
2598     assert( phi->req() == result->req(), "must have same number of inputs.");
2599     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
2600 #endif
2601     // Check if all new phi's inputs have specified alias index.
2602     // Otherwise use old phi.
2603     for (uint i = 1; i < phi->req(); i++) {
2604       Node* in = result->in(i);
2605       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
2606     }
2607     // we have finished processing a Phi, see if there are any more to do
2608     finished = (phi_list.length() == 0 );
2609     if (!finished) {
2610       phi = phi_list.pop();
2611       idx = cur_input.pop();
2612       PhiNode *prev_result = get_map_phi(phi->_idx);
2613       prev_result->set_req(idx++, result);
2614       result = prev_result;
2615     }
2616   }
2617   return result;
2618 }
2619 
2620 //
2621 // The next methods are derived from methods in MemNode.
2622 //
2623 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
2624   Node *mem = mmem;
2625   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
2626   // means an array I have not precisely typed yet.  Do not do any
2627   // alias stuff with it any time soon.
2628   if (toop->base() != Type::AnyPtr &&
2629       !(toop->klass() != NULL &&
2630         toop->klass()->is_java_lang_Object() &&
2631         toop->offset() == Type::OffsetBot)) {
2632     mem = mmem->memory_at(alias_idx);
2633     // Update input if it is progress over what we have now
2634   }
2635   return mem;
2636 }
2637 
2638 //
2639 // Move memory users to their memory slices.
2640 //
2641 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
2642   Compile* C = _compile;
2643   PhaseGVN* igvn = _igvn;
2644   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
2645   assert(tp != NULL, "ptr type");
2646   int alias_idx = C->get_alias_index(tp);
2647   int general_idx = C->get_general_index(alias_idx);
2648 
2649   // Move users first
2650   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2651     Node* use = n->fast_out(i);
2652     if (use->is_MergeMem()) {
2653       MergeMemNode* mmem = use->as_MergeMem();
2654       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
2655       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
2656         continue; // Nothing to do
2657       }
2658       // Replace previous general reference to mem node.
2659       uint orig_uniq = C->unique();
2660       Node* m = find_inst_mem(n, general_idx, orig_phis);
2661       assert(orig_uniq == C->unique(), "no new nodes");
2662       mmem->set_memory_at(general_idx, m);
2663       --imax;
2664       --i;
2665     } else if (use->is_MemBar()) {
2666       assert(!use->is_Initialize(), "initializing stores should not be moved");
2667       if (use->req() > MemBarNode::Precedent &&
2668           use->in(MemBarNode::Precedent) == n) {
2669         // Don't move related membars.
2670         record_for_optimizer(use);
2671         continue;
2672       }
2673       tp = use->as_MemBar()->adr_type()->isa_ptr();
2674       if ((tp != NULL && C->get_alias_index(tp) == alias_idx) ||
2675           alias_idx == general_idx) {
2676         continue; // Nothing to do
2677       }
2678       // Move to general memory slice.
2679       uint orig_uniq = C->unique();
2680       Node* m = find_inst_mem(n, general_idx, orig_phis);
2681       assert(orig_uniq == C->unique(), "no new nodes");
2682       igvn->hash_delete(use);
2683       imax -= use->replace_edge(n, m);
2684       igvn->hash_insert(use);
2685       record_for_optimizer(use);
2686       --i;
2687 #ifdef ASSERT
2688     } else if (use->is_Mem()) {
2689       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
2690         // Don't move related cardmark.
2691         continue;
2692       }
2693       // Memory nodes should have new memory input.
2694       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
2695       assert(tp != NULL, "ptr type");
2696       int idx = C->get_alias_index(tp);
2697       assert(get_map(use->_idx) != NULL || idx == alias_idx,
2698              "Following memory nodes should have new memory input or be on the same memory slice");
2699     } else if (use->is_Phi()) {
2700       // Phi nodes should be split and moved already.
2701       tp = use->as_Phi()->adr_type()->isa_ptr();
2702       assert(tp != NULL, "ptr type");
2703       int idx = C->get_alias_index(tp);
2704       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
2705     } else {
2706       use->dump();
2707       assert(false, "should not be here");
2708 #endif
2709     }
2710   }
2711 }
2712 
2713 //
2714 // Search memory chain of "mem" to find a MemNode whose address
2715 // is the specified alias index.
2716 //
2717 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis) {
2718   if (orig_mem == NULL)
2719     return orig_mem;
2720   Compile* C = _compile;
2721   PhaseGVN* igvn = _igvn;
2722   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
2723   bool is_instance = (toop != NULL) && toop->is_known_instance();
2724   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
2725   Node *prev = NULL;
2726   Node *result = orig_mem;
2727   while (prev != result) {
2728     prev = result;
2729     if (result == start_mem)
2730       break;  // hit one of our sentinels
2731     if (result->is_Mem()) {
2732       const Type *at = igvn->type(result->in(MemNode::Address));
2733       if (at == Type::TOP)
2734         break; // Dead
2735       assert (at->isa_ptr() != NULL, "pointer type required.");
2736       int idx = C->get_alias_index(at->is_ptr());
2737       if (idx == alias_idx)
2738         break; // Found
2739       if (!is_instance && (at->isa_oopptr() == NULL ||
2740                            !at->is_oopptr()->is_known_instance())) {
2741         break; // Do not skip store to general memory slice.
2742       }
2743       result = result->in(MemNode::Memory);
2744     }
2745     if (!is_instance)
2746       continue;  // don't search further for non-instance types
2747     // skip over a call which does not affect this memory slice
2748     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
2749       Node *proj_in = result->in(0);
2750       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
2751         break;  // hit one of our sentinels
2752       } else if (proj_in->is_Call()) {
2753         // ArrayCopy node processed here as well
2754         CallNode *call = proj_in->as_Call();
2755         if (!call->may_modify(toop, igvn)) {
2756           result = call->in(TypeFunc::Memory);
2757         }
2758       } else if (proj_in->is_Initialize()) {
2759         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
2760         // Stop if this is the initialization for the object instance which
2761         // which contains this memory slice, otherwise skip over it.
2762         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
2763           result = proj_in->in(TypeFunc::Memory);
2764         }
2765       } else if (proj_in->is_MemBar()) {
2766         // Check if there is an array copy for a clone
2767         // Step over GC barrier when ReduceInitialCardMarks is disabled
2768         BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
2769         Node* control_proj_ac = bs->step_over_gc_barrier(proj_in->in(0));
2770 
2771         if (control_proj_ac->is_Proj() && control_proj_ac->in(0)->is_ArrayCopy()) {
2772           // Stop if it is a clone
2773           ArrayCopyNode* ac = control_proj_ac->in(0)->as_ArrayCopy();
2774           if (ac->may_modify(toop, igvn)) {
2775             break;
2776           }
2777         }
2778         result = proj_in->in(TypeFunc::Memory);
2779       }
2780     } else if (result->is_MergeMem()) {
2781       MergeMemNode *mmem = result->as_MergeMem();
2782       result = step_through_mergemem(mmem, alias_idx, toop);
2783       if (result == mmem->base_memory()) {
2784         // Didn't find instance memory, search through general slice recursively.
2785         result = mmem->memory_at(C->get_general_index(alias_idx));
2786         result = find_inst_mem(result, alias_idx, orig_phis);
2787         if (C->failing()) {
2788           return NULL;
2789         }
2790         mmem->set_memory_at(alias_idx, result);
2791       }
2792     } else if (result->is_Phi() &&
2793                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
2794       Node *un = result->as_Phi()->unique_input(igvn);
2795       if (un != NULL) {
2796         orig_phis.append_if_missing(result->as_Phi());
2797         result = un;
2798       } else {
2799         break;
2800       }
2801     } else if (result->is_ClearArray()) {
2802       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
2803         // Can not bypass initialization of the instance
2804         // we are looking for.
2805         break;
2806       }
2807       // Otherwise skip it (the call updated 'result' value).
2808     } else if (result->Opcode() == Op_SCMemProj) {
2809       Node* mem = result->in(0);
2810       Node* adr = NULL;
2811       if (mem->is_LoadStore()) {
2812         adr = mem->in(MemNode::Address);
2813       } else {
2814         assert(mem->Opcode() == Op_EncodeISOArray ||
2815                mem->Opcode() == Op_StrCompressedCopy, "sanity");
2816         adr = mem->in(3); // Memory edge corresponds to destination array
2817       }
2818       const Type *at = igvn->type(adr);
2819       if (at != Type::TOP) {
2820         assert(at->isa_ptr() != NULL, "pointer type required.");
2821         int idx = C->get_alias_index(at->is_ptr());
2822         if (idx == alias_idx) {
2823           // Assert in debug mode
2824           assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
2825           break; // In product mode return SCMemProj node
2826         }
2827       }
2828       result = mem->in(MemNode::Memory);
2829     } else if (result->Opcode() == Op_StrInflatedCopy) {
2830       Node* adr = result->in(3); // Memory edge corresponds to destination array
2831       const Type *at = igvn->type(adr);
2832       if (at != Type::TOP) {
2833         assert(at->isa_ptr() != NULL, "pointer type required.");
2834         int idx = C->get_alias_index(at->is_ptr());
2835         if (idx == alias_idx) {
2836           // Assert in debug mode
2837           assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
2838           break; // In product mode return SCMemProj node
2839         }
2840       }
2841       result = result->in(MemNode::Memory);
2842     }
2843   }
2844   if (result->is_Phi()) {
2845     PhiNode *mphi = result->as_Phi();
2846     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
2847     const TypePtr *t = mphi->adr_type();
2848     if (!is_instance) {
2849       // Push all non-instance Phis on the orig_phis worklist to update inputs
2850       // during Phase 4 if needed.
2851       orig_phis.append_if_missing(mphi);
2852     } else if (C->get_alias_index(t) != alias_idx) {
2853       // Create a new Phi with the specified alias index type.
2854       result = split_memory_phi(mphi, alias_idx, orig_phis);
2855     }
2856   }
2857   // the result is either MemNode, PhiNode, InitializeNode.
2858   return result;
2859 }
2860 
2861 //
2862 //  Convert the types of unescaped object to instance types where possible,
2863 //  propagate the new type information through the graph, and update memory
2864 //  edges and MergeMem inputs to reflect the new type.
2865 //
2866 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
2867 //  The processing is done in 4 phases:
2868 //
2869 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
2870 //            types for the CheckCastPP for allocations where possible.
2871 //            Propagate the new types through users as follows:
2872 //               casts and Phi:  push users on alloc_worklist
2873 //               AddP:  cast Base and Address inputs to the instance type
2874 //                      push any AddP users on alloc_worklist and push any memnode
2875 //                      users onto memnode_worklist.
2876 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
2877 //            search the Memory chain for a store with the appropriate type
2878 //            address type.  If a Phi is found, create a new version with
2879 //            the appropriate memory slices from each of the Phi inputs.
2880 //            For stores, process the users as follows:
2881 //               MemNode:  push on memnode_worklist
2882 //               MergeMem: push on mergemem_worklist
2883 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
2884 //            moving the first node encountered of each  instance type to the
2885 //            the input corresponding to its alias index.
2886 //            appropriate memory slice.
2887 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
2888 //
2889 // In the following example, the CheckCastPP nodes are the cast of allocation
2890 // results and the allocation of node 29 is unescaped and eligible to be an
2891 // instance type.
2892 //
2893 // We start with:
2894 //
2895 //     7 Parm #memory
2896 //    10  ConI  "12"
2897 //    19  CheckCastPP   "Foo"
2898 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2899 //    29  CheckCastPP   "Foo"
2900 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
2901 //
2902 //    40  StoreP  25   7  20   ... alias_index=4
2903 //    50  StoreP  35  40  30   ... alias_index=4
2904 //    60  StoreP  45  50  20   ... alias_index=4
2905 //    70  LoadP    _  60  30   ... alias_index=4
2906 //    80  Phi     75  50  60   Memory alias_index=4
2907 //    90  LoadP    _  80  30   ... alias_index=4
2908 //   100  LoadP    _  80  20   ... alias_index=4
2909 //
2910 //
2911 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
2912 // and creating a new alias index for node 30.  This gives:
2913 //
2914 //     7 Parm #memory
2915 //    10  ConI  "12"
2916 //    19  CheckCastPP   "Foo"
2917 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2918 //    29  CheckCastPP   "Foo"  iid=24
2919 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2920 //
2921 //    40  StoreP  25   7  20   ... alias_index=4
2922 //    50  StoreP  35  40  30   ... alias_index=6
2923 //    60  StoreP  45  50  20   ... alias_index=4
2924 //    70  LoadP    _  60  30   ... alias_index=6
2925 //    80  Phi     75  50  60   Memory alias_index=4
2926 //    90  LoadP    _  80  30   ... alias_index=6
2927 //   100  LoadP    _  80  20   ... alias_index=4
2928 //
2929 // In phase 2, new memory inputs are computed for the loads and stores,
2930 // And a new version of the phi is created.  In phase 4, the inputs to
2931 // node 80 are updated and then the memory nodes are updated with the
2932 // values computed in phase 2.  This results in:
2933 //
2934 //     7 Parm #memory
2935 //    10  ConI  "12"
2936 //    19  CheckCastPP   "Foo"
2937 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2938 //    29  CheckCastPP   "Foo"  iid=24
2939 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2940 //
2941 //    40  StoreP  25  7   20   ... alias_index=4
2942 //    50  StoreP  35  7   30   ... alias_index=6
2943 //    60  StoreP  45  40  20   ... alias_index=4
2944 //    70  LoadP    _  50  30   ... alias_index=6
2945 //    80  Phi     75  40  60   Memory alias_index=4
2946 //   120  Phi     75  50  50   Memory alias_index=6
2947 //    90  LoadP    _ 120  30   ... alias_index=6
2948 //   100  LoadP    _  80  20   ... alias_index=4
2949 //
2950 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist, GrowableArray<ArrayCopyNode*> &arraycopy_worklist) {
2951   GrowableArray<Node *>  memnode_worklist;
2952   GrowableArray<PhiNode *>  orig_phis;
2953   PhaseIterGVN  *igvn = _igvn;
2954   uint new_index_start = (uint) _compile->num_alias_types();
2955   VectorSet visited;
2956   ideal_nodes.clear(); // Reset for use with set_map/get_map.
2957   uint unique_old = _compile->unique();
2958 
2959   //  Phase 1:  Process possible allocations from alloc_worklist.
2960   //  Create instance types for the CheckCastPP for allocations where possible.
2961   //
2962   // (Note: don't forget to change the order of the second AddP node on
2963   //  the alloc_worklist if the order of the worklist processing is changed,
2964   //  see the comment in find_second_addp().)
2965   //
2966   while (alloc_worklist.length() != 0) {
2967     Node *n = alloc_worklist.pop();
2968     uint ni = n->_idx;
2969     if (n->is_Call()) {
2970       CallNode *alloc = n->as_Call();
2971       // copy escape information to call node
2972       PointsToNode* ptn = ptnode_adr(alloc->_idx);
2973       PointsToNode::EscapeState es = ptn->escape_state();
2974       // We have an allocation or call which returns a Java object,
2975       // see if it is unescaped.
2976       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
2977         continue;
2978       // Find CheckCastPP for the allocate or for the return value of a call
2979       n = alloc->result_cast();
2980       if (n == NULL) {            // No uses except Initialize node
2981         if (alloc->is_Allocate()) {
2982           // Set the scalar_replaceable flag for allocation
2983           // so it could be eliminated if it has no uses.
2984           alloc->as_Allocate()->_is_scalar_replaceable = true;
2985         }
2986         if (alloc->is_CallStaticJava()) {
2987           // Set the scalar_replaceable flag for boxing method
2988           // so it could be eliminated if it has no uses.
2989           alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2990         }
2991         continue;
2992       }
2993       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
2994         // we could reach here for allocate case if one init is associated with many allocs.
2995         if (alloc->is_Allocate()) {
2996           alloc->as_Allocate()->_is_scalar_replaceable = false;
2997         }
2998         continue;
2999       }
3000 
3001       // The inline code for Object.clone() casts the allocation result to
3002       // java.lang.Object and then to the actual type of the allocated
3003       // object. Detect this case and use the second cast.
3004       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
3005       // the allocation result is cast to java.lang.Object and then
3006       // to the actual Array type.
3007       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
3008           && (alloc->is_AllocateArray() ||
3009               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
3010         Node *cast2 = NULL;
3011         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3012           Node *use = n->fast_out(i);
3013           if (use->is_CheckCastPP()) {
3014             cast2 = use;
3015             break;
3016           }
3017         }
3018         if (cast2 != NULL) {
3019           n = cast2;
3020         } else {
3021           // Non-scalar replaceable if the allocation type is unknown statically
3022           // (reflection allocation), the object can't be restored during
3023           // deoptimization without precise type.
3024           continue;
3025         }
3026       }
3027 
3028       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
3029       if (t == NULL)
3030         continue;  // not a TypeOopPtr
3031       if (!t->klass_is_exact())
3032         continue; // not an unique type
3033 
3034       if (alloc->is_Allocate()) {
3035         // Set the scalar_replaceable flag for allocation
3036         // so it could be eliminated.
3037         alloc->as_Allocate()->_is_scalar_replaceable = true;
3038       }
3039       if (alloc->is_CallStaticJava()) {
3040         // Set the scalar_replaceable flag for boxing method
3041         // so it could be eliminated.
3042         alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
3043       }
3044       set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
3045       // in order for an object to be scalar-replaceable, it must be:
3046       //   - a direct allocation (not a call returning an object)
3047       //   - non-escaping
3048       //   - eligible to be a unique type
3049       //   - not determined to be ineligible by escape analysis
3050       set_map(alloc, n);
3051       set_map(n, alloc);
3052       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
3053       igvn->hash_delete(n);
3054       igvn->set_type(n,  tinst);
3055       n->raise_bottom_type(tinst);
3056       igvn->hash_insert(n);
3057       record_for_optimizer(n);
3058       // Allocate an alias index for the header fields. Accesses to
3059       // the header emitted during macro expansion wouldn't have
3060       // correct memory state otherwise.
3061       _compile->get_alias_index(tinst->add_offset(oopDesc::mark_offset_in_bytes()));
3062       _compile->get_alias_index(tinst->add_offset(oopDesc::klass_offset_in_bytes()));
3063       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
3064 
3065         // First, put on the worklist all Field edges from Connection Graph
3066         // which is more accurate than putting immediate users from Ideal Graph.
3067         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
3068           PointsToNode* tgt = e.get();
3069           if (tgt->is_Arraycopy()) {
3070             continue;
3071           }
3072           Node* use = tgt->ideal_node();
3073           assert(tgt->is_Field() && use->is_AddP(),
3074                  "only AddP nodes are Field edges in CG");
3075           if (use->outcnt() > 0) { // Don't process dead nodes
3076             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
3077             if (addp2 != NULL) {
3078               assert(alloc->is_AllocateArray(),"array allocation was expected");
3079               alloc_worklist.append_if_missing(addp2);
3080             }
3081             alloc_worklist.append_if_missing(use);
3082           }
3083         }
3084 
3085         // An allocation may have an Initialize which has raw stores. Scan
3086         // the users of the raw allocation result and push AddP users
3087         // on alloc_worklist.
3088         Node *raw_result = alloc->proj_out_or_null(TypeFunc::Parms);
3089         assert (raw_result != NULL, "must have an allocation result");
3090         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
3091           Node *use = raw_result->fast_out(i);
3092           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
3093             Node* addp2 = find_second_addp(use, raw_result);
3094             if (addp2 != NULL) {
3095               assert(alloc->is_AllocateArray(),"array allocation was expected");
3096               alloc_worklist.append_if_missing(addp2);
3097             }
3098             alloc_worklist.append_if_missing(use);
3099           } else if (use->is_MemBar()) {
3100             memnode_worklist.append_if_missing(use);
3101           }
3102         }
3103       }
3104     } else if (n->is_AddP()) {
3105       JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
3106       if (jobj == NULL || jobj == phantom_obj) {
3107 #ifdef ASSERT
3108         ptnode_adr(get_addp_base(n)->_idx)->dump();
3109         ptnode_adr(n->_idx)->dump();
3110         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3111 #endif
3112         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3113         return;
3114       }
3115       Node *base = get_map(jobj->idx());  // CheckCastPP node
3116       if (!split_AddP(n, base)) continue; // wrong type from dead path
3117     } else if (n->is_Phi() ||
3118                n->is_CheckCastPP() ||
3119                n->is_EncodeP() ||
3120                n->is_DecodeN() ||
3121                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
3122       if (visited.test_set(n->_idx)) {
3123         assert(n->is_Phi(), "loops only through Phi's");
3124         continue;  // already processed
3125       }
3126       JavaObjectNode* jobj = unique_java_object(n);
3127       if (jobj == NULL || jobj == phantom_obj) {
3128 #ifdef ASSERT
3129         ptnode_adr(n->_idx)->dump();
3130         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3131 #endif
3132         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3133         return;
3134       } else {
3135         Node *val = get_map(jobj->idx());   // CheckCastPP node
3136         TypeNode *tn = n->as_Type();
3137         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
3138         assert(tinst != NULL && tinst->is_known_instance() &&
3139                tinst->instance_id() == jobj->idx() , "instance type expected.");
3140 
3141         const Type *tn_type = igvn->type(tn);
3142         const TypeOopPtr *tn_t;
3143         if (tn_type->isa_narrowoop()) {
3144           tn_t = tn_type->make_ptr()->isa_oopptr();
3145         } else {
3146           tn_t = tn_type->isa_oopptr();
3147         }
3148         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
3149           if (tn_type->isa_narrowoop()) {
3150             tn_type = tinst->make_narrowoop();
3151           } else {
3152             tn_type = tinst;
3153           }
3154           igvn->hash_delete(tn);
3155           igvn->set_type(tn, tn_type);
3156           tn->set_type(tn_type);
3157           igvn->hash_insert(tn);
3158           record_for_optimizer(n);
3159         } else {
3160           assert(tn_type == TypePtr::NULL_PTR ||
3161                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
3162                  "unexpected type");
3163           continue; // Skip dead path with different type
3164         }
3165       }
3166     } else {
3167       debug_only(n->dump();)
3168       assert(false, "EA: unexpected node");
3169       continue;
3170     }
3171     // push allocation's users on appropriate worklist
3172     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3173       Node *use = n->fast_out(i);
3174       if(use->is_Mem() && use->in(MemNode::Address) == n) {
3175         // Load/store to instance's field
3176         memnode_worklist.append_if_missing(use);
3177       } else if (use->is_MemBar()) {
3178         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3179           memnode_worklist.append_if_missing(use);
3180         }
3181       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
3182         Node* addp2 = find_second_addp(use, n);
3183         if (addp2 != NULL) {
3184           alloc_worklist.append_if_missing(addp2);
3185         }
3186         alloc_worklist.append_if_missing(use);
3187       } else if (use->is_Phi() ||
3188                  use->is_CheckCastPP() ||
3189                  use->is_EncodeNarrowPtr() ||
3190                  use->is_DecodeNarrowPtr() ||
3191                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
3192         alloc_worklist.append_if_missing(use);
3193 #ifdef ASSERT
3194       } else if (use->is_Mem()) {
3195         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
3196       } else if (use->is_MergeMem()) {
3197         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3198       } else if (use->is_SafePoint()) {
3199         // Look for MergeMem nodes for calls which reference unique allocation
3200         // (through CheckCastPP nodes) even for debug info.
3201         Node* m = use->in(TypeFunc::Memory);
3202         if (m->is_MergeMem()) {
3203           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3204         }
3205       } else if (use->Opcode() == Op_EncodeISOArray) {
3206         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3207           // EncodeISOArray overwrites destination array
3208           memnode_worklist.append_if_missing(use);
3209         }
3210       } else {
3211         uint op = use->Opcode();
3212         if ((op == Op_StrCompressedCopy || op == Op_StrInflatedCopy) &&
3213             (use->in(MemNode::Memory) == n)) {
3214           // They overwrite memory edge corresponding to destination array,
3215           memnode_worklist.append_if_missing(use);
3216         } else if (!(op == Op_CmpP || op == Op_Conv2B ||
3217               op == Op_CastP2X || op == Op_StoreCM ||
3218               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp || op == Op_HasNegatives ||
3219               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
3220               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar ||
3221               op == Op_SubTypeCheck ||
3222               BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(use))) {
3223           n->dump();
3224           use->dump();
3225           assert(false, "EA: missing allocation reference path");
3226         }
3227 #endif
3228       }
3229     }
3230 
3231   }
3232 
3233   // Go over all ArrayCopy nodes and if one of the inputs has a unique
3234   // type, record it in the ArrayCopy node so we know what memory this
3235   // node uses/modified.
3236   for (int next = 0; next < arraycopy_worklist.length(); next++) {
3237     ArrayCopyNode* ac = arraycopy_worklist.at(next);
3238     Node* dest = ac->in(ArrayCopyNode::Dest);
3239     if (dest->is_AddP()) {
3240       dest = get_addp_base(dest);
3241     }
3242     JavaObjectNode* jobj = unique_java_object(dest);
3243     if (jobj != NULL) {
3244       Node *base = get_map(jobj->idx());
3245       if (base != NULL) {
3246         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3247         ac->_dest_type = base_t;
3248       }
3249     }
3250     Node* src = ac->in(ArrayCopyNode::Src);
3251     if (src->is_AddP()) {
3252       src = get_addp_base(src);
3253     }
3254     jobj = unique_java_object(src);
3255     if (jobj != NULL) {
3256       Node* base = get_map(jobj->idx());
3257       if (base != NULL) {
3258         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3259         ac->_src_type = base_t;
3260       }
3261     }
3262   }
3263 
3264   // New alias types were created in split_AddP().
3265   uint new_index_end = (uint) _compile->num_alias_types();
3266   assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
3267 
3268   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
3269   //            compute new values for Memory inputs  (the Memory inputs are not
3270   //            actually updated until phase 4.)
3271   if (memnode_worklist.length() == 0)
3272     return;  // nothing to do
3273   while (memnode_worklist.length() != 0) {
3274     Node *n = memnode_worklist.pop();
3275     if (visited.test_set(n->_idx))
3276       continue;
3277     if (n->is_Phi() || n->is_ClearArray()) {
3278       // we don't need to do anything, but the users must be pushed
3279     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
3280       // we don't need to do anything, but the users must be pushed
3281       n = n->as_MemBar()->proj_out_or_null(TypeFunc::Memory);
3282       if (n == NULL)
3283         continue;
3284     } else if (n->Opcode() == Op_StrCompressedCopy ||
3285                n->Opcode() == Op_EncodeISOArray) {
3286       // get the memory projection
3287       n = n->find_out_with(Op_SCMemProj);
3288       assert(n != NULL && n->Opcode() == Op_SCMemProj, "memory projection required");
3289     } else {
3290       assert(n->is_Mem(), "memory node required.");
3291       Node *addr = n->in(MemNode::Address);
3292       const Type *addr_t = igvn->type(addr);
3293       if (addr_t == Type::TOP)
3294         continue;
3295       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
3296       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
3297       assert ((uint)alias_idx < new_index_end, "wrong alias index");
3298       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
3299       if (_compile->failing()) {
3300         return;
3301       }
3302       if (mem != n->in(MemNode::Memory)) {
3303         // We delay the memory edge update since we need old one in
3304         // MergeMem code below when instances memory slices are separated.
3305         set_map(n, mem);
3306       }
3307       if (n->is_Load()) {
3308         continue;  // don't push users
3309       } else if (n->is_LoadStore()) {
3310         // get the memory projection
3311         n = n->find_out_with(Op_SCMemProj);
3312         assert(n != NULL && n->Opcode() == Op_SCMemProj, "memory projection required");
3313       }
3314     }
3315     // push user on appropriate worklist
3316     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3317       Node *use = n->fast_out(i);
3318       if (use->is_Phi() || use->is_ClearArray()) {
3319         memnode_worklist.append_if_missing(use);
3320       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
3321         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
3322           continue;
3323         memnode_worklist.append_if_missing(use);
3324       } else if (use->is_MemBar()) {
3325         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3326           memnode_worklist.append_if_missing(use);
3327         }
3328 #ifdef ASSERT
3329       } else if(use->is_Mem()) {
3330         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
3331       } else if (use->is_MergeMem()) {
3332         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3333       } else if (use->Opcode() == Op_EncodeISOArray) {
3334         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3335           // EncodeISOArray overwrites destination array
3336           memnode_worklist.append_if_missing(use);
3337         }
3338       } else {
3339         uint op = use->Opcode();
3340         if ((use->in(MemNode::Memory) == n) &&
3341             (op == Op_StrCompressedCopy || op == Op_StrInflatedCopy)) {
3342           // They overwrite memory edge corresponding to destination array,
3343           memnode_worklist.append_if_missing(use);
3344         } else if (!(BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(use) ||
3345               op == Op_AryEq || op == Op_StrComp || op == Op_HasNegatives ||
3346               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
3347               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar)) {
3348           n->dump();
3349           use->dump();
3350           assert(false, "EA: missing memory path");
3351         }
3352 #endif
3353       }
3354     }
3355   }
3356 
3357   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
3358   //            Walk each memory slice moving the first node encountered of each
3359   //            instance type to the the input corresponding to its alias index.
3360   uint length = _mergemem_worklist.length();
3361   for( uint next = 0; next < length; ++next ) {
3362     MergeMemNode* nmm = _mergemem_worklist.at(next);
3363     assert(!visited.test_set(nmm->_idx), "should not be visited before");
3364     // Note: we don't want to use MergeMemStream here because we only want to
3365     // scan inputs which exist at the start, not ones we add during processing.
3366     // Note 2: MergeMem may already contains instance memory slices added
3367     // during find_inst_mem() call when memory nodes were processed above.
3368     igvn->hash_delete(nmm);
3369     uint nslices = MIN2(nmm->req(), new_index_start);
3370     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
3371       Node* mem = nmm->in(i);
3372       Node* cur = NULL;
3373       if (mem == NULL || mem->is_top())
3374         continue;
3375       // First, update mergemem by moving memory nodes to corresponding slices
3376       // if their type became more precise since this mergemem was created.
3377       while (mem->is_Mem()) {
3378         const Type *at = igvn->type(mem->in(MemNode::Address));
3379         if (at != Type::TOP) {
3380           assert (at->isa_ptr() != NULL, "pointer type required.");
3381           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
3382           if (idx == i) {
3383             if (cur == NULL)
3384               cur = mem;
3385           } else {
3386             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
3387               nmm->set_memory_at(idx, mem);
3388             }
3389           }
3390         }
3391         mem = mem->in(MemNode::Memory);
3392       }
3393       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
3394       // Find any instance of the current type if we haven't encountered
3395       // already a memory slice of the instance along the memory chain.
3396       for (uint ni = new_index_start; ni < new_index_end; ni++) {
3397         if((uint)_compile->get_general_index(ni) == i) {
3398           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
3399           if (nmm->is_empty_memory(m)) {
3400             Node* result = find_inst_mem(mem, ni, orig_phis);
3401             if (_compile->failing()) {
3402               return;
3403             }
3404             nmm->set_memory_at(ni, result);
3405           }
3406         }
3407       }
3408     }
3409     // Find the rest of instances values
3410     for (uint ni = new_index_start; ni < new_index_end; ni++) {
3411       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
3412       Node* result = step_through_mergemem(nmm, ni, tinst);
3413       if (result == nmm->base_memory()) {
3414         // Didn't find instance memory, search through general slice recursively.
3415         result = nmm->memory_at(_compile->get_general_index(ni));
3416         result = find_inst_mem(result, ni, orig_phis);
3417         if (_compile->failing()) {
3418           return;
3419         }
3420         nmm->set_memory_at(ni, result);
3421       }
3422     }
3423     igvn->hash_insert(nmm);
3424     record_for_optimizer(nmm);
3425   }
3426 
3427   //  Phase 4:  Update the inputs of non-instance memory Phis and
3428   //            the Memory input of memnodes
3429   // First update the inputs of any non-instance Phi's from
3430   // which we split out an instance Phi.  Note we don't have
3431   // to recursively process Phi's encounted on the input memory
3432   // chains as is done in split_memory_phi() since they  will
3433   // also be processed here.
3434   for (int j = 0; j < orig_phis.length(); j++) {
3435     PhiNode *phi = orig_phis.at(j);
3436     int alias_idx = _compile->get_alias_index(phi->adr_type());
3437     igvn->hash_delete(phi);
3438     for (uint i = 1; i < phi->req(); i++) {
3439       Node *mem = phi->in(i);
3440       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
3441       if (_compile->failing()) {
3442         return;
3443       }
3444       if (mem != new_mem) {
3445         phi->set_req(i, new_mem);
3446       }
3447     }
3448     igvn->hash_insert(phi);
3449     record_for_optimizer(phi);
3450   }
3451 
3452   // Update the memory inputs of MemNodes with the value we computed
3453   // in Phase 2 and move stores memory users to corresponding memory slices.
3454   // Disable memory split verification code until the fix for 6984348.
3455   // Currently it produces false negative results since it does not cover all cases.
3456 #if 0 // ifdef ASSERT
3457   visited.Reset();
3458   Node_Stack old_mems(arena, _compile->unique() >> 2);
3459 #endif
3460   for (uint i = 0; i < ideal_nodes.size(); i++) {
3461     Node*    n = ideal_nodes.at(i);
3462     Node* nmem = get_map(n->_idx);
3463     assert(nmem != NULL, "sanity");
3464     if (n->is_Mem()) {
3465 #if 0 // ifdef ASSERT
3466       Node* old_mem = n->in(MemNode::Memory);
3467       if (!visited.test_set(old_mem->_idx)) {
3468         old_mems.push(old_mem, old_mem->outcnt());
3469       }
3470 #endif
3471       assert(n->in(MemNode::Memory) != nmem, "sanity");
3472       if (!n->is_Load()) {
3473         // Move memory users of a store first.
3474         move_inst_mem(n, orig_phis);
3475       }
3476       // Now update memory input
3477       igvn->hash_delete(n);
3478       n->set_req(MemNode::Memory, nmem);
3479       igvn->hash_insert(n);
3480       record_for_optimizer(n);
3481     } else {
3482       assert(n->is_Allocate() || n->is_CheckCastPP() ||
3483              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
3484     }
3485   }
3486 #if 0 // ifdef ASSERT
3487   // Verify that memory was split correctly
3488   while (old_mems.is_nonempty()) {
3489     Node* old_mem = old_mems.node();
3490     uint  old_cnt = old_mems.index();
3491     old_mems.pop();
3492     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
3493   }
3494 #endif
3495 }
3496 
3497 #ifndef PRODUCT
3498 static const char *node_type_names[] = {
3499   "UnknownType",
3500   "JavaObject",
3501   "LocalVar",
3502   "Field",
3503   "Arraycopy"
3504 };
3505 
3506 static const char *esc_names[] = {
3507   "UnknownEscape",
3508   "NoEscape",
3509   "ArgEscape",
3510   "GlobalEscape"
3511 };
3512 
3513 void PointsToNode::dump(bool print_state) const {
3514   NodeType nt = node_type();
3515   tty->print("%s ", node_type_names[(int) nt]);
3516   if (print_state) {
3517     EscapeState es = escape_state();
3518     EscapeState fields_es = fields_escape_state();
3519     tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
3520     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
3521       tty->print("NSR ");
3522   }
3523   if (is_Field()) {
3524     FieldNode* f = (FieldNode*)this;
3525     if (f->is_oop())
3526       tty->print("oop ");
3527     if (f->offset() > 0)
3528       tty->print("+%d ", f->offset());
3529     tty->print("(");
3530     for (BaseIterator i(f); i.has_next(); i.next()) {
3531       PointsToNode* b = i.get();
3532       tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
3533     }
3534     tty->print(" )");
3535   }
3536   tty->print("[");
3537   for (EdgeIterator i(this); i.has_next(); i.next()) {
3538     PointsToNode* e = i.get();
3539     tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
3540   }
3541   tty->print(" [");
3542   for (UseIterator i(this); i.has_next(); i.next()) {
3543     PointsToNode* u = i.get();
3544     bool is_base = false;
3545     if (PointsToNode::is_base_use(u)) {
3546       is_base = true;
3547       u = PointsToNode::get_use_node(u)->as_Field();
3548     }
3549     tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
3550   }
3551   tty->print(" ]]  ");
3552   if (_node == NULL)
3553     tty->print_cr("<null>");
3554   else
3555     _node->dump();
3556 }
3557 
3558 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
3559   bool first = true;
3560   int ptnodes_length = ptnodes_worklist.length();
3561   for (int i = 0; i < ptnodes_length; i++) {
3562     PointsToNode *ptn = ptnodes_worklist.at(i);
3563     if (ptn == NULL || !ptn->is_JavaObject())
3564       continue;
3565     PointsToNode::EscapeState es = ptn->escape_state();
3566     if ((es != PointsToNode::NoEscape) && !Verbose) {
3567       continue;
3568     }
3569     Node* n = ptn->ideal_node();
3570     if (n->is_Allocate() || (n->is_CallStaticJava() &&
3571                              n->as_CallStaticJava()->is_boxing_method())) {
3572       if (first) {
3573         tty->cr();
3574         tty->print("======== Connection graph for ");
3575         _compile->method()->print_short_name();
3576         tty->cr();
3577         first = false;
3578       }
3579       ptn->dump();
3580       // Print all locals and fields which reference this allocation
3581       for (UseIterator j(ptn); j.has_next(); j.next()) {
3582         PointsToNode* use = j.get();
3583         if (use->is_LocalVar()) {
3584           use->dump(Verbose);
3585         } else if (Verbose) {
3586           use->dump();
3587         }
3588       }
3589       tty->cr();
3590     }
3591   }
3592 }
3593 #endif
3594 
3595 void ConnectionGraph::record_for_optimizer(Node *n) {
3596   _igvn->_worklist.push(n);
3597   _igvn->add_users_to_worklist(n);
3598 }