1 /*
   2  * Copyright (c) 2005, 2015, 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 "libadt/vectset.hpp"
  29 #include "memory/allocation.hpp"
  30 #include "opto/c2compiler.hpp"
  31 #include "opto/arraycopynode.hpp"
  32 #include "opto/callnode.hpp"
  33 #include "opto/cfgnode.hpp"
  34 #include "opto/compile.hpp"
  35 #include "opto/escape.hpp"
  36 #include "opto/phaseX.hpp"
  37 #include "opto/movenode.hpp"
  38 #include "opto/rootnode.hpp"
  39 
  40 ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :
  41   _nodes(C->comp_arena(), C->unique(), C->unique(), NULL),
  42   _in_worklist(C->comp_arena()),
  43   _next_pidx(0),
  44   _collecting(true),
  45   _verify(false),
  46   _compile(C),
  47   _igvn(igvn),
  48   _node_map(C->comp_arena()) {
  49   // Add unknown java object.
  50   add_java_object(C->top(), PointsToNode::GlobalEscape);
  51   phantom_obj = ptnode_adr(C->top()->_idx)->as_JavaObject();
  52   // Add ConP(#NULL) and ConN(#NULL) nodes.
  53   Node* oop_null = igvn->zerocon(T_OBJECT);
  54   assert(oop_null->_idx < nodes_size(), "should be created already");
  55   add_java_object(oop_null, PointsToNode::NoEscape);
  56   null_obj = ptnode_adr(oop_null->_idx)->as_JavaObject();
  57   if (UseCompressedOops) {
  58     Node* noop_null = igvn->zerocon(T_NARROWOOP);
  59     assert(noop_null->_idx < nodes_size(), "should be created already");
  60     map_ideal_node(noop_null, null_obj);
  61   }
  62   _pcmp_neq = NULL; // Should be initialized
  63   _pcmp_eq  = NULL;
  64 }
  65 
  66 bool ConnectionGraph::has_candidates(Compile *C) {
  67   // EA brings benefits only when the code has allocations and/or locks which
  68   // are represented by ideal Macro nodes.
  69   int cnt = C->macro_count();
  70   for (int i = 0; i < cnt; i++) {
  71     Node *n = C->macro_node(i);
  72     if (n->is_Allocate())
  73       return true;
  74     if (n->is_Lock()) {
  75       Node* obj = n->as_Lock()->obj_node()->uncast();
  76       if (!(obj->is_Parm() || obj->is_Con()))
  77         return true;
  78     }
  79     if (n->is_CallStaticJava() &&
  80         n->as_CallStaticJava()->is_boxing_method()) {
  81       return true;
  82     }
  83   }
  84   return false;
  85 }
  86 
  87 void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {
  88   Compile::TracePhase tp("escapeAnalysis", &Phase::timers[Phase::_t_escapeAnalysis]);
  89   ResourceMark rm;
  90 
  91   // Add ConP#NULL and ConN#NULL nodes before ConnectionGraph construction
  92   // to create space for them in ConnectionGraph::_nodes[].
  93   Node* oop_null = igvn->zerocon(T_OBJECT);
  94   Node* noop_null = igvn->zerocon(T_NARROWOOP);
  95   ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn);
  96   // Perform escape analysis
  97   if (congraph->compute_escape()) {
  98     // There are non escaping objects.
  99     C->set_congraph(congraph);
 100   }
 101   // Cleanup.
 102   if (oop_null->outcnt() == 0)
 103     igvn->hash_delete(oop_null);
 104   if (noop_null->outcnt() == 0)
 105     igvn->hash_delete(noop_null);
 106 }
 107 
 108 bool ConnectionGraph::compute_escape() {
 109   Compile* C = _compile;
 110   PhaseGVN* igvn = _igvn;
 111 
 112   // Worklists used by EA.
 113   Unique_Node_List delayed_worklist;
 114   GrowableArray<Node*> alloc_worklist;
 115   GrowableArray<Node*> ptr_cmp_worklist;
 116   GrowableArray<Node*> storestore_worklist;
 117   GrowableArray<ArrayCopyNode*> arraycopy_worklist;
 118   GrowableArray<PointsToNode*>   ptnodes_worklist;
 119   GrowableArray<JavaObjectNode*> java_objects_worklist;
 120   GrowableArray<JavaObjectNode*> non_escaped_worklist;
 121   GrowableArray<FieldNode*>      oop_fields_worklist;
 122   DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
 123 
 124   { Compile::TracePhase tp("connectionGraph", &Phase::timers[Phase::_t_connectionGraph]);
 125 
 126   // 1. Populate Connection Graph (CG) with PointsTo nodes.
 127   ideal_nodes.map(C->live_nodes(), NULL);  // preallocate space
 128   // Initialize worklist
 129   if (C->root() != NULL) {
 130     ideal_nodes.push(C->root());
 131   }
 132   // Processed ideal nodes are unique on ideal_nodes list
 133   // but several ideal nodes are mapped to the phantom_obj.
 134   // To avoid duplicated entries on the following worklists
 135   // add the phantom_obj only once to them.
 136   ptnodes_worklist.append(phantom_obj);
 137   java_objects_worklist.append(phantom_obj);
 138   for( uint next = 0; next < ideal_nodes.size(); ++next ) {
 139     Node* n = ideal_nodes.at(next);
 140     // Create PointsTo nodes and add them to Connection Graph. Called
 141     // only once per ideal node since ideal_nodes is Unique_Node list.
 142     add_node_to_connection_graph(n, &delayed_worklist);
 143     PointsToNode* ptn = ptnode_adr(n->_idx);
 144     if (ptn != NULL && ptn != phantom_obj) {
 145       ptnodes_worklist.append(ptn);
 146       if (ptn->is_JavaObject()) {
 147         java_objects_worklist.append(ptn->as_JavaObject());
 148         if ((n->is_Allocate() || n->is_CallStaticJava()) &&
 149             (ptn->escape_state() < PointsToNode::GlobalEscape)) {
 150           // Only allocations and java static calls results are interesting.
 151           non_escaped_worklist.append(ptn->as_JavaObject());
 152         }
 153       } else if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
 154         oop_fields_worklist.append(ptn->as_Field());
 155       }
 156     }
 157     if (n->is_MergeMem()) {
 158       // Collect all MergeMem nodes to add memory slices for
 159       // scalar replaceable objects in split_unique_types().
 160       _mergemem_worklist.append(n->as_MergeMem());
 161     } else if (OptimizePtrCompare && n->is_Cmp() &&
 162                (n->Opcode() == Op_CmpP || n->Opcode() == Op_CmpN)) {
 163       // Collect compare pointers nodes.
 164       ptr_cmp_worklist.append(n);
 165     } else if (n->is_MemBarStoreStore()) {
 166       // Collect all MemBarStoreStore nodes so that depending on the
 167       // escape status of the associated Allocate node some of them
 168       // may be eliminated.
 169       storestore_worklist.append(n);
 170     } else if (n->is_MemBar() && (n->Opcode() == Op_MemBarRelease) &&
 171                (n->req() > MemBarNode::Precedent)) {
 172       record_for_optimizer(n);
 173 #ifdef ASSERT
 174     } else if (n->is_AddP()) {
 175       // Collect address nodes for graph verification.
 176       addp_worklist.append(n);
 177 #endif
 178     } else if (n->is_ArrayCopy()) {
 179       // Keep a list of ArrayCopy nodes so if one of its input is non
 180       // escaping, we can record a unique type
 181       arraycopy_worklist.append(n->as_ArrayCopy());
 182     }
 183     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 184       Node* m = n->fast_out(i);   // Get user
 185       ideal_nodes.push(m);
 186     }
 187   }
 188   if (non_escaped_worklist.length() == 0) {
 189     _collecting = false;
 190     return false; // Nothing to do.
 191   }
 192   // Add final simple edges to graph.
 193   while(delayed_worklist.size() > 0) {
 194     Node* n = delayed_worklist.pop();
 195     add_final_edges(n);
 196   }
 197   int ptnodes_length = ptnodes_worklist.length();
 198 
 199 #ifdef ASSERT
 200   if (VerifyConnectionGraph) {
 201     // Verify that no new simple edges could be created and all
 202     // local vars has edges.
 203     _verify = true;
 204     for (int next = 0; next < ptnodes_length; ++next) {
 205       PointsToNode* ptn = ptnodes_worklist.at(next);
 206       add_final_edges(ptn->ideal_node());
 207       if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
 208         ptn->dump();
 209         assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
 210       }
 211     }
 212     _verify = false;
 213   }
 214 #endif
 215   // Bytecode analyzer BCEscapeAnalyzer, used for Call nodes
 216   // processing, calls to CI to resolve symbols (types, fields, methods)
 217   // referenced in bytecode. During symbol resolution VM may throw
 218   // an exception which CI cleans and converts to compilation failure.
 219   if (C->failing())  return false;
 220 
 221   // 2. Finish Graph construction by propagating references to all
 222   //    java objects through graph.
 223   if (!complete_connection_graph(ptnodes_worklist, non_escaped_worklist,
 224                                  java_objects_worklist, oop_fields_worklist)) {
 225     // All objects escaped or hit time or iterations limits.
 226     _collecting = false;
 227     return false;
 228   }
 229 
 230   // 3. Adjust scalar_replaceable state of nonescaping objects and push
 231   //    scalar replaceable allocations on alloc_worklist for processing
 232   //    in split_unique_types().
 233   int non_escaped_length = non_escaped_worklist.length();
 234   for (int next = 0; next < non_escaped_length; next++) {
 235     JavaObjectNode* ptn = non_escaped_worklist.at(next);
 236     bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
 237     Node* n = ptn->ideal_node();
 238     if (n->is_Allocate()) {
 239       n->as_Allocate()->_is_non_escaping = noescape;
 240     }
 241     if (n->is_CallStaticJava()) {
 242       n->as_CallStaticJava()->_is_non_escaping = noescape;
 243     }
 244     if (noescape && ptn->scalar_replaceable()) {
 245       adjust_scalar_replaceable_state(ptn);
 246       if (ptn->scalar_replaceable()) {
 247         alloc_worklist.append(ptn->ideal_node());
 248       }
 249     }
 250   }
 251 
 252 #ifdef ASSERT
 253   if (VerifyConnectionGraph) {
 254     // Verify that graph is complete - no new edges could be added or needed.
 255     verify_connection_graph(ptnodes_worklist, non_escaped_worklist,
 256                             java_objects_worklist, addp_worklist);
 257   }
 258   assert(C->unique() == nodes_size(), "no new ideal nodes should be added during ConnectionGraph build");
 259   assert(null_obj->escape_state() == PointsToNode::NoEscape &&
 260          null_obj->edge_count() == 0 &&
 261          !null_obj->arraycopy_src() &&
 262          !null_obj->arraycopy_dst(), "sanity");
 263 #endif
 264 
 265   _collecting = false;
 266 
 267   } // TracePhase t3("connectionGraph")
 268 
 269   // 4. Optimize ideal graph based on EA information.
 270   bool has_non_escaping_obj = (non_escaped_worklist.length() > 0);
 271   if (has_non_escaping_obj) {
 272     optimize_ideal_graph(ptr_cmp_worklist, storestore_worklist);
 273   }
 274 
 275 #ifndef PRODUCT
 276   if (PrintEscapeAnalysis) {
 277     dump(ptnodes_worklist); // Dump ConnectionGraph
 278   }
 279 #endif
 280 
 281   bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
 282 #ifdef ASSERT
 283   if (VerifyConnectionGraph) {
 284     int alloc_length = alloc_worklist.length();
 285     for (int next = 0; next < alloc_length; ++next) {
 286       Node* n = alloc_worklist.at(next);
 287       PointsToNode* ptn = ptnode_adr(n->_idx);
 288       assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
 289     }
 290   }
 291 #endif
 292 
 293   // 5. Separate memory graph for scalar replaceable allcations.
 294   if (has_scalar_replaceable_candidates &&
 295       C->AliasLevel() >= 3 && EliminateAllocations) {
 296     // Now use the escape information to create unique types for
 297     // scalar replaceable objects.
 298     split_unique_types(alloc_worklist, arraycopy_worklist);
 299     if (C->failing())  return false;
 300     C->print_method(PHASE_AFTER_EA, 2);
 301 
 302 #ifdef ASSERT
 303   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
 304     tty->print("=== No allocations eliminated for ");
 305     C->method()->print_short_name();
 306     if(!EliminateAllocations) {
 307       tty->print(" since EliminateAllocations is off ===");
 308     } else if(!has_scalar_replaceable_candidates) {
 309       tty->print(" since there are no scalar replaceable candidates ===");
 310     } else if(C->AliasLevel() < 3) {
 311       tty->print(" since AliasLevel < 3 ===");
 312     }
 313     tty->cr();
 314 #endif
 315   }
 316   return has_non_escaping_obj;
 317 }
 318 
 319 // Utility function for nodes that load an object
 320 void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 321   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 322   // ThreadLocal has RawPtr type.
 323   const Type* t = _igvn->type(n);
 324   if (t->make_ptr() != NULL) {
 325     Node* adr = n->in(MemNode::Address);
 326 #ifdef ASSERT
 327     if (!adr->is_AddP()) {
 328       assert(_igvn->type(adr)->isa_rawptr(), "sanity");
 329     } else {
 330       assert((ptnode_adr(adr->_idx) == NULL ||
 331               ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
 332     }
 333 #endif
 334     add_local_var_and_edge(n, PointsToNode::NoEscape,
 335                            adr, delayed_worklist);
 336   }
 337 }
 338 
 339 // Populate Connection Graph with PointsTo nodes and create simple
 340 // connection graph edges.
 341 void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 342   assert(!_verify, "this method should not be called for verification");
 343   PhaseGVN* igvn = _igvn;
 344   uint n_idx = n->_idx;
 345   PointsToNode* n_ptn = ptnode_adr(n_idx);
 346   if (n_ptn != NULL)
 347     return; // No need to redefine PointsTo node during first iteration.
 348 
 349   if (n->is_Call()) {
 350     // Arguments to allocation and locking don't escape.
 351     if (n->is_AbstractLock()) {
 352       // Put Lock and Unlock nodes on IGVN worklist to process them during
 353       // first IGVN optimization when escape information is still available.
 354       record_for_optimizer(n);
 355     } else if (n->is_Allocate()) {
 356       add_call_node(n->as_Call());
 357       record_for_optimizer(n);
 358     } else {
 359       if (n->is_CallStaticJava()) {
 360         const char* name = n->as_CallStaticJava()->_name;
 361         if (name != NULL && strcmp(name, "uncommon_trap") == 0)
 362           return; // Skip uncommon traps
 363       }
 364       // Don't mark as processed since call's arguments have to be processed.
 365       delayed_worklist->push(n);
 366       // Check if a call returns an object.
 367       if ((n->as_Call()->returns_pointer() &&
 368            n->as_Call()->proj_out(TypeFunc::Parms) != NULL) ||
 369           (n->is_CallStaticJava() &&
 370            n->as_CallStaticJava()->is_boxing_method())) {
 371         add_call_node(n->as_Call());
 372       }
 373     }
 374     return;
 375   }
 376   // Put this check here to process call arguments since some call nodes
 377   // point to phantom_obj.
 378   if (n_ptn == phantom_obj || n_ptn == null_obj)
 379     return; // Skip predefined nodes.
 380 
 381   int opcode = n->Opcode();
 382   switch (opcode) {
 383     case Op_AddP: {
 384       Node* base = get_addp_base(n);
 385       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 386       // Field nodes are created for all field types. They are used in
 387       // adjust_scalar_replaceable_state() and split_unique_types().
 388       // Note, non-oop fields will have only base edges in Connection
 389       // Graph because such fields are not used for oop loads and stores.
 390       int offset = address_offset(n, igvn);
 391       add_field(n, PointsToNode::NoEscape, offset);
 392       if (ptn_base == NULL) {
 393         delayed_worklist->push(n); // Process it later.
 394       } else {
 395         n_ptn = ptnode_adr(n_idx);
 396         add_base(n_ptn->as_Field(), ptn_base);
 397       }
 398       break;
 399     }
 400     case Op_CastX2P: {
 401       map_ideal_node(n, phantom_obj);
 402       break;
 403     }
 404     case Op_CastPP:
 405     case Op_CheckCastPP:
 406     case Op_EncodeP:
 407     case Op_DecodeN:
 408     case Op_EncodePKlass:
 409     case Op_DecodeNKlass: {
 410       add_local_var_and_edge(n, PointsToNode::NoEscape,
 411                              n->in(1), delayed_worklist);
 412       break;
 413     }
 414     case Op_CMoveP: {
 415       add_local_var(n, PointsToNode::NoEscape);
 416       // Do not add edges during first iteration because some could be
 417       // not defined yet.
 418       delayed_worklist->push(n);
 419       break;
 420     }
 421     case Op_ConP:
 422     case Op_ConN:
 423     case Op_ConNKlass: {
 424       // assume all oop constants globally escape except for null
 425       PointsToNode::EscapeState es;
 426       const Type* t = igvn->type(n);
 427       if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
 428         es = PointsToNode::NoEscape;
 429       } else {
 430         es = PointsToNode::GlobalEscape;
 431       }
 432       add_java_object(n, es);
 433       break;
 434     }
 435     case Op_CreateEx: {
 436       // assume that all exception objects globally escape
 437       map_ideal_node(n, phantom_obj);
 438       break;
 439     }
 440     case Op_LoadKlass:
 441     case Op_LoadNKlass: {
 442       // Unknown class is loaded
 443       map_ideal_node(n, phantom_obj);
 444       break;
 445     }
 446     case Op_LoadP:
 447     case Op_LoadN:
 448     case Op_LoadPLocked: {
 449       add_objload_to_connection_graph(n, delayed_worklist);
 450       break;
 451     }
 452     case Op_Parm: {
 453       map_ideal_node(n, phantom_obj);
 454       break;
 455     }
 456     case Op_PartialSubtypeCheck: {
 457       // Produces Null or notNull and is used in only in CmpP so
 458       // phantom_obj could be used.
 459       map_ideal_node(n, phantom_obj); // Result is unknown
 460       break;
 461     }
 462     case Op_Phi: {
 463       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 464       // ThreadLocal has RawPtr type.
 465       const Type* t = n->as_Phi()->type();
 466       if (t->make_ptr() != NULL) {
 467         add_local_var(n, PointsToNode::NoEscape);
 468         // Do not add edges during first iteration because some could be
 469         // not defined yet.
 470         delayed_worklist->push(n);
 471       }
 472       break;
 473     }
 474     case Op_Proj: {
 475       // we are only interested in the oop result projection from a call
 476       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 477           n->in(0)->as_Call()->returns_pointer()) {
 478         add_local_var_and_edge(n, PointsToNode::NoEscape,
 479                                n->in(0), delayed_worklist);
 480       }
 481       break;
 482     }
 483     case Op_Rethrow: // Exception object escapes
 484     case Op_Return: {
 485       if (n->req() > TypeFunc::Parms &&
 486           igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 487         // Treat Return value as LocalVar with GlobalEscape escape state.
 488         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 489                                n->in(TypeFunc::Parms), delayed_worklist);
 490       }
 491       break;
 492     }
 493     case Op_CompareAndExchangeP:
 494     case Op_CompareAndExchangeN:
 495     case Op_GetAndSetP:
 496     case Op_GetAndSetN: {
 497       add_objload_to_connection_graph(n, delayed_worklist);
 498       // fallthrough
 499     }
 500     case Op_StoreP:
 501     case Op_StoreN:
 502     case Op_StoreNKlass:
 503     case Op_StorePConditional:
 504     case Op_WeakCompareAndSwapP:
 505     case Op_WeakCompareAndSwapN:
 506     case Op_CompareAndSwapP:
 507     case Op_CompareAndSwapN: {
 508       Node* adr = n->in(MemNode::Address);
 509       const Type *adr_type = igvn->type(adr);
 510       adr_type = adr_type->make_ptr();
 511       if (adr_type == NULL) {
 512         break; // skip dead nodes
 513       }
 514       if (adr_type->isa_oopptr() ||
 515           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
 516                         (adr_type == TypeRawPtr::NOTNULL &&
 517                          adr->in(AddPNode::Address)->is_Proj() &&
 518                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
 519         delayed_worklist->push(n); // Process it later.
 520 #ifdef ASSERT
 521         assert(adr->is_AddP(), "expecting an AddP");
 522         if (adr_type == TypeRawPtr::NOTNULL) {
 523           // Verify a raw address for a store captured by Initialize node.
 524           int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 525           assert(offs != Type::OffsetBot, "offset must be a constant");
 526         }
 527 #endif
 528       } else {
 529         // Ignore copy the displaced header to the BoxNode (OSR compilation).
 530         if (adr->is_BoxLock())
 531           break;
 532         // Stored value escapes in unsafe access.
 533         if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
 534           // Pointer stores in G1 barriers looks like unsafe access.
 535           // Ignore such stores to be able scalar replace non-escaping
 536           // allocations.
 537           if (UseG1GC && adr->is_AddP()) {
 538             Node* base = get_addp_base(adr);
 539             if (base->Opcode() == Op_LoadP &&
 540                 base->in(MemNode::Address)->is_AddP()) {
 541               adr = base->in(MemNode::Address);
 542               Node* tls = get_addp_base(adr);
 543               if (tls->Opcode() == Op_ThreadLocal) {
 544                 int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 545                 if (offs == in_bytes(JavaThread::satb_mark_queue_offset() +
 546                                      SATBMarkQueue::byte_offset_of_buf())) {
 547                   break; // G1 pre barrier previous oop value store.
 548                 }
 549                 if (offs == in_bytes(JavaThread::dirty_card_queue_offset() +
 550                                      DirtyCardQueue::byte_offset_of_buf())) {
 551                   break; // G1 post barrier card address store.
 552                 }
 553               }
 554             }
 555           }
 556           delayed_worklist->push(n); // Process unsafe access later.
 557           break;
 558         }
 559 #ifdef ASSERT
 560         n->dump(1);
 561         assert(false, "not unsafe or G1 barrier raw StoreP");
 562 #endif
 563       }
 564       break;
 565     }
 566     case Op_AryEq:
 567     case Op_HasNegatives:
 568     case Op_StrComp:
 569     case Op_StrEquals:
 570     case Op_StrIndexOf:
 571     case Op_StrIndexOfChar:
 572     case Op_StrInflatedCopy:
 573     case Op_StrCompressedCopy:
 574     case Op_EncodeISOArray: {
 575       add_local_var(n, PointsToNode::ArgEscape);
 576       delayed_worklist->push(n); // Process it later.
 577       break;
 578     }
 579     case Op_ThreadLocal: {
 580       add_java_object(n, PointsToNode::ArgEscape);
 581       break;
 582     }
 583     default:
 584       ; // Do nothing for nodes not related to EA.
 585   }
 586   return;
 587 }
 588 
 589 #ifdef ASSERT
 590 #define ELSE_FAIL(name)                               \
 591       /* Should not be called for not pointer type. */  \
 592       n->dump(1);                                       \
 593       assert(false, name);                              \
 594       break;
 595 #else
 596 #define ELSE_FAIL(name) \
 597       break;
 598 #endif
 599 
 600 // Add final simple edges to graph.
 601 void ConnectionGraph::add_final_edges(Node *n) {
 602   PointsToNode* n_ptn = ptnode_adr(n->_idx);
 603 #ifdef ASSERT
 604   if (_verify && n_ptn->is_JavaObject())
 605     return; // This method does not change graph for JavaObject.
 606 #endif
 607 
 608   if (n->is_Call()) {
 609     process_call_arguments(n->as_Call());
 610     return;
 611   }
 612   assert(n->is_Store() || n->is_LoadStore() ||
 613          (n_ptn != NULL) && (n_ptn->ideal_node() != NULL),
 614          "node should be registered already");
 615   int opcode = n->Opcode();
 616   switch (opcode) {
 617     case Op_AddP: {
 618       Node* base = get_addp_base(n);
 619       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 620       assert(ptn_base != NULL, "field's base should be registered");
 621       add_base(n_ptn->as_Field(), ptn_base);
 622       break;
 623     }
 624     case Op_CastPP:
 625     case Op_CheckCastPP:
 626     case Op_EncodeP:
 627     case Op_DecodeN:
 628     case Op_EncodePKlass:
 629     case Op_DecodeNKlass: {
 630       add_local_var_and_edge(n, PointsToNode::NoEscape,
 631                              n->in(1), NULL);
 632       break;
 633     }
 634     case Op_CMoveP: {
 635       for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
 636         Node* in = n->in(i);
 637         if (in == NULL)
 638           continue;  // ignore NULL
 639         Node* uncast_in = in->uncast();
 640         if (uncast_in->is_top() || uncast_in == n)
 641           continue;  // ignore top or inputs which go back this node
 642         PointsToNode* ptn = ptnode_adr(in->_idx);
 643         assert(ptn != NULL, "node should be registered");
 644         add_edge(n_ptn, ptn);
 645       }
 646       break;
 647     }
 648     case Op_LoadP:
 649     case Op_LoadN:
 650     case Op_LoadPLocked: {
 651       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 652       // ThreadLocal has RawPtr type.
 653       const Type* t = _igvn->type(n);
 654       if (t->make_ptr() != NULL) {
 655         Node* adr = n->in(MemNode::Address);
 656         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 657         break;
 658       }
 659       ELSE_FAIL("Op_LoadP");
 660     }
 661     case Op_Phi: {
 662       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 663       // ThreadLocal has RawPtr type.
 664       const Type* t = n->as_Phi()->type();
 665       if (t->make_ptr() != NULL) {
 666         for (uint i = 1; i < n->req(); i++) {
 667           Node* in = n->in(i);
 668           if (in == NULL)
 669             continue;  // ignore NULL
 670           Node* uncast_in = in->uncast();
 671           if (uncast_in->is_top() || uncast_in == n)
 672             continue;  // ignore top or inputs which go back this node
 673           PointsToNode* ptn = ptnode_adr(in->_idx);
 674           assert(ptn != NULL, "node should be registered");
 675           add_edge(n_ptn, ptn);
 676         }
 677         break;
 678       }
 679       ELSE_FAIL("Op_Phi");
 680     }
 681     case Op_Proj: {
 682       // we are only interested in the oop result projection from a call
 683       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 684           n->in(0)->as_Call()->returns_pointer()) {
 685         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), NULL);
 686         break;
 687       }
 688       ELSE_FAIL("Op_Proj");
 689     }
 690     case Op_Rethrow: // Exception object escapes
 691     case Op_Return: {
 692       if (n->req() > TypeFunc::Parms &&
 693           _igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 694         // Treat Return value as LocalVar with GlobalEscape escape state.
 695         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 696                                n->in(TypeFunc::Parms), NULL);
 697         break;
 698       }
 699       ELSE_FAIL("Op_Return");
 700     }
 701     case Op_StoreP:
 702     case Op_StoreN:
 703     case Op_StoreNKlass:
 704     case Op_StorePConditional:
 705     case Op_CompareAndExchangeP:
 706     case Op_CompareAndExchangeN:
 707     case Op_CompareAndSwapP:
 708     case Op_CompareAndSwapN:
 709     case Op_WeakCompareAndSwapP:
 710     case Op_WeakCompareAndSwapN:
 711     case Op_GetAndSetP:
 712     case Op_GetAndSetN: {
 713       Node* adr = n->in(MemNode::Address);
 714       const Type *adr_type = _igvn->type(adr);
 715       adr_type = adr_type->make_ptr();
 716 #ifdef ASSERT
 717       if (adr_type == NULL) {
 718         n->dump(1);
 719         assert(adr_type != NULL, "dead node should not be on list");
 720         break;
 721       }
 722 #endif
 723       if (opcode == Op_GetAndSetP || opcode == Op_GetAndSetN) {
 724         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 725       }
 726       if (adr_type->isa_oopptr() ||
 727           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
 728                         (adr_type == TypeRawPtr::NOTNULL &&
 729                          adr->in(AddPNode::Address)->is_Proj() &&
 730                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
 731         // Point Address to Value
 732         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 733         assert(adr_ptn != NULL &&
 734                adr_ptn->as_Field()->is_oop(), "node should be registered");
 735         Node *val = n->in(MemNode::ValueIn);
 736         PointsToNode* ptn = ptnode_adr(val->_idx);
 737         assert(ptn != NULL, "node should be registered");
 738         add_edge(adr_ptn, ptn);
 739         break;
 740       } else if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
 741         // Stored value escapes in unsafe access.
 742         Node *val = n->in(MemNode::ValueIn);
 743         PointsToNode* ptn = ptnode_adr(val->_idx);
 744         assert(ptn != NULL, "node should be registered");
 745         set_escape_state(ptn, PointsToNode::GlobalEscape);
 746         // Add edge to object for unsafe access with offset.
 747         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 748         assert(adr_ptn != NULL, "node should be registered");
 749         if (adr_ptn->is_Field()) {
 750           assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
 751           add_edge(adr_ptn, ptn);
 752         }
 753         break;
 754       }
 755       ELSE_FAIL("Op_StoreP");
 756     }
 757     case Op_AryEq:
 758     case Op_HasNegatives:
 759     case Op_StrComp:
 760     case Op_StrEquals:
 761     case Op_StrIndexOf:
 762     case Op_StrIndexOfChar:
 763     case Op_StrInflatedCopy:
 764     case Op_StrCompressedCopy:
 765     case Op_EncodeISOArray: {
 766       // char[]/byte[] arrays passed to string intrinsic do not escape but
 767       // they are not scalar replaceable. Adjust escape state for them.
 768       // Start from in(2) edge since in(1) is memory edge.
 769       for (uint i = 2; i < n->req(); i++) {
 770         Node* adr = n->in(i);
 771         const Type* at = _igvn->type(adr);
 772         if (!adr->is_top() && at->isa_ptr()) {
 773           assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
 774                  at->isa_ptr() != NULL, "expecting a pointer");
 775           if (adr->is_AddP()) {
 776             adr = get_addp_base(adr);
 777           }
 778           PointsToNode* ptn = ptnode_adr(adr->_idx);
 779           assert(ptn != NULL, "node should be registered");
 780           add_edge(n_ptn, ptn);
 781         }
 782       }
 783       break;
 784     }
 785     default: {
 786       // This method should be called only for EA specific nodes which may
 787       // miss some edges when they were created.
 788 #ifdef ASSERT
 789       n->dump(1);
 790 #endif
 791       guarantee(false, "unknown node");
 792     }
 793   }
 794   return;
 795 }
 796 
 797 void ConnectionGraph::add_call_node(CallNode* call) {
 798   assert(call->returns_pointer(), "only for call which returns pointer");
 799   uint call_idx = call->_idx;
 800   if (call->is_Allocate()) {
 801     Node* k = call->in(AllocateNode::KlassNode);
 802     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
 803     assert(kt != NULL, "TypeKlassPtr  required.");
 804     ciKlass* cik = kt->klass();
 805     PointsToNode::EscapeState es = PointsToNode::NoEscape;
 806     bool scalar_replaceable = true;
 807     if (call->is_AllocateArray()) {
 808       if (!cik->is_array_klass()) { // StressReflectiveCode
 809         es = PointsToNode::GlobalEscape;
 810       } else {
 811         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
 812         if (length < 0 || length > EliminateAllocationArraySizeLimit) {
 813           // Not scalar replaceable if the length is not constant or too big.
 814           scalar_replaceable = false;
 815         }
 816       }
 817     } else {  // Allocate instance
 818       if (cik->is_subclass_of(_compile->env()->Thread_klass()) ||
 819           cik->is_subclass_of(_compile->env()->Reference_klass()) ||
 820          !cik->is_instance_klass() || // StressReflectiveCode
 821          !cik->as_instance_klass()->can_be_instantiated() ||
 822           cik->as_instance_klass()->has_finalizer()) {
 823         es = PointsToNode::GlobalEscape;
 824       }
 825     }
 826     add_java_object(call, es);
 827     PointsToNode* ptn = ptnode_adr(call_idx);
 828     if (!scalar_replaceable && ptn->scalar_replaceable()) {
 829       ptn->set_scalar_replaceable(false);
 830     }
 831   } else if (call->is_CallStaticJava()) {
 832     // Call nodes could be different types:
 833     //
 834     // 1. CallDynamicJavaNode (what happened during call is unknown):
 835     //
 836     //    - mapped to GlobalEscape JavaObject node if oop is returned;
 837     //
 838     //    - all oop arguments are escaping globally;
 839     //
 840     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
 841     //
 842     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
 843     //
 844     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
 845     //    - mapped to NoEscape JavaObject node if non-escaping object allocated
 846     //      during call is returned;
 847     //    - mapped to ArgEscape LocalVar node pointed to object arguments
 848     //      which are returned and does not escape during call;
 849     //
 850     //    - oop arguments escaping status is defined by bytecode analysis;
 851     //
 852     // For a static call, we know exactly what method is being called.
 853     // Use bytecode estimator to record whether the call's return value escapes.
 854     ciMethod* meth = call->as_CallJava()->method();
 855     if (meth == NULL) {
 856       const char* name = call->as_CallStaticJava()->_name;
 857       assert(strncmp(name, "_multianewarray", 15) == 0, "TODO: add failed case check");
 858       // Returns a newly allocated unescaped object.
 859       add_java_object(call, PointsToNode::NoEscape);
 860       ptnode_adr(call_idx)->set_scalar_replaceable(false);
 861     } else if (meth->is_boxing_method()) {
 862       // Returns boxing object
 863       PointsToNode::EscapeState es;
 864       vmIntrinsics::ID intr = meth->intrinsic_id();
 865       if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
 866         // It does not escape if object is always allocated.
 867         es = PointsToNode::NoEscape;
 868       } else {
 869         // It escapes globally if object could be loaded from cache.
 870         es = PointsToNode::GlobalEscape;
 871       }
 872       add_java_object(call, es);
 873     } else {
 874       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
 875       call_analyzer->copy_dependencies(_compile->dependencies());
 876       if (call_analyzer->is_return_allocated()) {
 877         // Returns a newly allocated unescaped object, simply
 878         // update dependency information.
 879         // Mark it as NoEscape so that objects referenced by
 880         // it's fields will be marked as NoEscape at least.
 881         add_java_object(call, PointsToNode::NoEscape);
 882         ptnode_adr(call_idx)->set_scalar_replaceable(false);
 883       } else {
 884         // Determine whether any arguments are returned.
 885         const TypeTuple* d = call->tf()->domain_sig();
 886         bool ret_arg = false;
 887         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 888           if (d->field_at(i)->isa_ptr() != NULL &&
 889               call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
 890             ret_arg = true;
 891             break;
 892           }
 893         }
 894         if (ret_arg) {
 895           add_local_var(call, PointsToNode::ArgEscape);
 896         } else {
 897           // Returns unknown object.
 898           map_ideal_node(call, phantom_obj);
 899         }
 900       }
 901     }
 902   } else {
 903     // An other type of call, assume the worst case:
 904     // returned value is unknown and globally escapes.
 905     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
 906     map_ideal_node(call, phantom_obj);
 907   }
 908 }
 909 
 910 void ConnectionGraph::process_call_arguments(CallNode *call) {
 911     bool is_arraycopy = false;
 912     switch (call->Opcode()) {
 913 #ifdef ASSERT
 914     case Op_Allocate:
 915     case Op_AllocateArray:
 916     case Op_Lock:
 917     case Op_Unlock:
 918       assert(false, "should be done already");
 919       break;
 920 #endif
 921     case Op_ArrayCopy:
 922     case Op_CallLeafNoFP:
 923       // Most array copies are ArrayCopy nodes at this point but there
 924       // are still a few direct calls to the copy subroutines (See
 925       // PhaseStringOpts::copy_string())
 926       is_arraycopy = (call->Opcode() == Op_ArrayCopy) ||
 927         call->as_CallLeaf()->is_call_to_arraycopystub();
 928       // fall through
 929     case Op_CallLeaf: {
 930       // Stub calls, objects do not escape but they are not scale replaceable.
 931       // Adjust escape state for outgoing arguments.
 932       const TypeTuple * d = call->tf()->domain_sig();
 933       bool src_has_oops = false;
 934       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 935         const Type* at = d->field_at(i);
 936         Node *arg = call->in(i);
 937         if (arg == NULL) {
 938           continue;
 939         }
 940         const Type *aat = _igvn->type(arg);
 941         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr())
 942           continue;
 943         if (arg->is_AddP()) {
 944           //
 945           // The inline_native_clone() case when the arraycopy stub is called
 946           // after the allocation before Initialize and CheckCastPP nodes.
 947           // Or normal arraycopy for object arrays case.
 948           //
 949           // Set AddP's base (Allocate) as not scalar replaceable since
 950           // pointer to the base (with offset) is passed as argument.
 951           //
 952           arg = get_addp_base(arg);
 953         }
 954         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
 955         assert(arg_ptn != NULL, "should be registered");
 956         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
 957         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
 958           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
 959                  aat->isa_ptr() != NULL, "expecting an Ptr");
 960           bool arg_has_oops = aat->isa_oopptr() &&
 961                               (aat->isa_oopptr()->klass() == NULL || aat->isa_instptr() ||
 962                                (aat->isa_aryptr() && aat->isa_aryptr()->klass()->is_obj_array_klass()));
 963           if (i == TypeFunc::Parms) {
 964             src_has_oops = arg_has_oops;
 965           }
 966           //
 967           // src or dst could be j.l.Object when other is basic type array:
 968           //
 969           //   arraycopy(char[],0,Object*,0,size);
 970           //   arraycopy(Object*,0,char[],0,size);
 971           //
 972           // Don't add edges in such cases.
 973           //
 974           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
 975                                        arg_has_oops && (i > TypeFunc::Parms);
 976 #ifdef ASSERT
 977           if (!(is_arraycopy ||
 978                 (call->as_CallLeaf()->_name != NULL &&
 979                  (strcmp(call->as_CallLeaf()->_name, "g1_wb_pre")  == 0 ||
 980                   strcmp(call->as_CallLeaf()->_name, "g1_wb_post") == 0 ||
 981                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
 982                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32C") == 0 ||
 983                   strcmp(call->as_CallLeaf()->_name, "updateBytesAdler32") == 0 ||
 984                   strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
 985                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
 986                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
 987                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
 988                   strcmp(call->as_CallLeaf()->_name, "counterMode_AESCrypt") == 0 ||
 989                   strcmp(call->as_CallLeaf()->_name, "ghash_processBlocks") == 0 ||
 990                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
 991                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
 992                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
 993                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
 994                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
 995                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
 996                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
 997                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
 998                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0 ||
 999                   strcmp(call->as_CallLeaf()->_name, "montgomery_multiply") == 0 ||
1000                   strcmp(call->as_CallLeaf()->_name, "montgomery_square") == 0 ||
1001                   strcmp(call->as_CallLeaf()->_name, "vectorizedMismatch") == 0)
1002                  ))) {
1003             call->dump();
1004             fatal("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name);
1005           }
1006 #endif
1007           // Always process arraycopy's destination object since
1008           // we need to add all possible edges to references in
1009           // source object.
1010           if (arg_esc >= PointsToNode::ArgEscape &&
1011               !arg_is_arraycopy_dest) {
1012             continue;
1013           }
1014           PointsToNode::EscapeState es = PointsToNode::ArgEscape;
1015           if (call->is_ArrayCopy()) {
1016             ArrayCopyNode* ac = call->as_ArrayCopy();
1017             if (ac->is_clonebasic() ||
1018                 ac->is_arraycopy_validated() ||
1019                 ac->is_copyof_validated() ||
1020                 ac->is_copyofrange_validated()) {
1021               es = PointsToNode::NoEscape;
1022             }
1023           }
1024           set_escape_state(arg_ptn, es);
1025           if (arg_is_arraycopy_dest) {
1026             Node* src = call->in(TypeFunc::Parms);
1027             if (src->is_AddP()) {
1028               src = get_addp_base(src);
1029             }
1030             PointsToNode* src_ptn = ptnode_adr(src->_idx);
1031             assert(src_ptn != NULL, "should be registered");
1032             if (arg_ptn != src_ptn) {
1033               // Special arraycopy edge:
1034               // A destination object's field can't have the source object
1035               // as base since objects escape states are not related.
1036               // Only escape state of destination object's fields affects
1037               // escape state of fields in source object.
1038               add_arraycopy(call, es, src_ptn, arg_ptn);
1039             }
1040           }
1041         }
1042       }
1043       break;
1044     }
1045     case Op_CallStaticJava: {
1046       // For a static call, we know exactly what method is being called.
1047       // Use bytecode estimator to record the call's escape affects
1048 #ifdef ASSERT
1049       const char* name = call->as_CallStaticJava()->_name;
1050       assert((name == NULL || strcmp(name, "uncommon_trap") != 0), "normal calls only");
1051 #endif
1052       ciMethod* meth = call->as_CallJava()->method();
1053       if ((meth != NULL) && meth->is_boxing_method()) {
1054         break; // Boxing methods do not modify any oops.
1055       }
1056       BCEscapeAnalyzer* call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
1057       // fall-through if not a Java method or no analyzer information
1058       if (call_analyzer != NULL) {
1059         PointsToNode* call_ptn = ptnode_adr(call->_idx);
1060         const TypeTuple* d = call->tf()->domain_sig();
1061         int extra = 0;
1062         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1063           const Type* at = d->field_at(i);
1064           if (at->isa_valuetypeptr()) {
1065             extra += at->is_valuetypeptr()->value_type()->value_klass()->field_count() - 1;
1066             continue;
1067           }
1068           int k = i - TypeFunc::Parms;
1069           Node* arg = call->in(i + extra);
1070           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
1071           if (at->isa_ptr() != NULL &&
1072               call_analyzer->is_arg_returned(k)) {
1073             // The call returns arguments.
1074             if (call_ptn != NULL) { // Is call's result used?
1075               assert(call_ptn->is_LocalVar(), "node should be registered");
1076               assert(arg_ptn != NULL, "node should be registered");
1077               add_edge(call_ptn, arg_ptn);
1078             }
1079           }
1080           if (at->isa_oopptr() != NULL &&
1081               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
1082             if (!call_analyzer->is_arg_stack(k)) {
1083               // The argument global escapes
1084               set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1085             } else {
1086               set_escape_state(arg_ptn, PointsToNode::ArgEscape);
1087               if (!call_analyzer->is_arg_local(k)) {
1088                 // The argument itself doesn't escape, but any fields might
1089                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1090               }
1091             }
1092           }
1093         }
1094         if (call_ptn != NULL && call_ptn->is_LocalVar()) {
1095           // The call returns arguments.
1096           assert(call_ptn->edge_count() > 0, "sanity");
1097           if (!call_analyzer->is_return_local()) {
1098             // Returns also unknown object.
1099             add_edge(call_ptn, phantom_obj);
1100           }
1101         }
1102         break;
1103       }
1104     }
1105     default: {
1106       // Fall-through here if not a Java method or no analyzer information
1107       // or some other type of call, assume the worst case: all arguments
1108       // globally escape.
1109       const TypeTuple* d = call->tf()->domain_sig();
1110       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1111         const Type* at = d->field_at(i);
1112         if (at->isa_oopptr() != NULL) {
1113           Node* arg = call->in(i);
1114           if (arg->is_AddP()) {
1115             arg = get_addp_base(arg);
1116           }
1117           assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
1118           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
1119         }
1120       }
1121     }
1122   }
1123 }
1124 
1125 
1126 // Finish Graph construction.
1127 bool ConnectionGraph::complete_connection_graph(
1128                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1129                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1130                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1131                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
1132   // Normally only 1-3 passes needed to build Connection Graph depending
1133   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
1134   // Set limit to 20 to catch situation when something did go wrong and
1135   // bailout Escape Analysis.
1136   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
1137 #define CG_BUILD_ITER_LIMIT 20
1138 
1139   // Propagate GlobalEscape and ArgEscape escape states and check that
1140   // we still have non-escaping objects. The method pushs on _worklist
1141   // Field nodes which reference phantom_object.
1142   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1143     return false; // Nothing to do.
1144   }
1145   // Now propagate references to all JavaObject nodes.
1146   int java_objects_length = java_objects_worklist.length();
1147   elapsedTimer time;
1148   bool timeout = false;
1149   int new_edges = 1;
1150   int iterations = 0;
1151   do {
1152     while ((new_edges > 0) &&
1153            (iterations++ < CG_BUILD_ITER_LIMIT)) {
1154       double start_time = time.seconds();
1155       time.start();
1156       new_edges = 0;
1157       // Propagate references to phantom_object for nodes pushed on _worklist
1158       // by find_non_escaped_objects() and find_field_value().
1159       new_edges += add_java_object_edges(phantom_obj, false);
1160       for (int next = 0; next < java_objects_length; ++next) {
1161         JavaObjectNode* ptn = java_objects_worklist.at(next);
1162         new_edges += add_java_object_edges(ptn, true);
1163 
1164 #define SAMPLE_SIZE 4
1165         if ((next % SAMPLE_SIZE) == 0) {
1166           // Each 4 iterations calculate how much time it will take
1167           // to complete graph construction.
1168           time.stop();
1169           // Poll for requests from shutdown mechanism to quiesce compiler
1170           // because Connection graph construction may take long time.
1171           CompileBroker::maybe_block();
1172           double stop_time = time.seconds();
1173           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
1174           double time_until_end = time_per_iter * (double)(java_objects_length - next);
1175           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
1176             timeout = true;
1177             break; // Timeout
1178           }
1179           start_time = stop_time;
1180           time.start();
1181         }
1182 #undef SAMPLE_SIZE
1183 
1184       }
1185       if (timeout) break;
1186       if (new_edges > 0) {
1187         // Update escape states on each iteration if graph was updated.
1188         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1189           return false; // Nothing to do.
1190         }
1191       }
1192       time.stop();
1193       if (time.seconds() >= EscapeAnalysisTimeout) {
1194         timeout = true;
1195         break;
1196       }
1197     }
1198     if ((iterations < CG_BUILD_ITER_LIMIT) && !timeout) {
1199       time.start();
1200       // Find fields which have unknown value.
1201       int fields_length = oop_fields_worklist.length();
1202       for (int next = 0; next < fields_length; next++) {
1203         FieldNode* field = oop_fields_worklist.at(next);
1204         if (field->edge_count() == 0) {
1205           new_edges += find_field_value(field);
1206           // This code may added new edges to phantom_object.
1207           // Need an other cycle to propagate references to phantom_object.
1208         }
1209       }
1210       time.stop();
1211       if (time.seconds() >= EscapeAnalysisTimeout) {
1212         timeout = true;
1213         break;
1214       }
1215     } else {
1216       new_edges = 0; // Bailout
1217     }
1218   } while (new_edges > 0);
1219 
1220   // Bailout if passed limits.
1221   if ((iterations >= CG_BUILD_ITER_LIMIT) || timeout) {
1222     Compile* C = _compile;
1223     if (C->log() != NULL) {
1224       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
1225       C->log()->text("%s", timeout ? "time" : "iterations");
1226       C->log()->end_elem(" limit'");
1227     }
1228     assert(ExitEscapeAnalysisOnTimeout, "infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
1229            time.seconds(), iterations, nodes_size(), ptnodes_worklist.length());
1230     // Possible infinite build_connection_graph loop,
1231     // bailout (no changes to ideal graph were made).
1232     return false;
1233   }
1234 #ifdef ASSERT
1235   if (Verbose && PrintEscapeAnalysis) {
1236     tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
1237                   iterations, nodes_size(), ptnodes_worklist.length());
1238   }
1239 #endif
1240 
1241 #undef CG_BUILD_ITER_LIMIT
1242 
1243   // Find fields initialized by NULL for non-escaping Allocations.
1244   int non_escaped_length = non_escaped_worklist.length();
1245   for (int next = 0; next < non_escaped_length; next++) {
1246     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1247     PointsToNode::EscapeState es = ptn->escape_state();
1248     assert(es <= PointsToNode::ArgEscape, "sanity");
1249     if (es == PointsToNode::NoEscape) {
1250       if (find_init_values(ptn, null_obj, _igvn) > 0) {
1251         // Adding references to NULL object does not change escape states
1252         // since it does not escape. Also no fields are added to NULL object.
1253         add_java_object_edges(null_obj, false);
1254       }
1255     }
1256     Node* n = ptn->ideal_node();
1257     if (n->is_Allocate()) {
1258       // The object allocated by this Allocate node will never be
1259       // seen by an other thread. Mark it so that when it is
1260       // expanded no MemBarStoreStore is added.
1261       InitializeNode* ini = n->as_Allocate()->initialization();
1262       if (ini != NULL)
1263         ini->set_does_not_escape();
1264     }
1265   }
1266   return true; // Finished graph construction.
1267 }
1268 
1269 // Propagate GlobalEscape and ArgEscape escape states to all nodes
1270 // and check that we still have non-escaping java objects.
1271 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
1272                                                GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
1273   GrowableArray<PointsToNode*> escape_worklist;
1274   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
1275   int ptnodes_length = ptnodes_worklist.length();
1276   for (int next = 0; next < ptnodes_length; ++next) {
1277     PointsToNode* ptn = ptnodes_worklist.at(next);
1278     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
1279         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
1280       escape_worklist.push(ptn);
1281     }
1282   }
1283   // Set escape states to referenced nodes (edges list).
1284   while (escape_worklist.length() > 0) {
1285     PointsToNode* ptn = escape_worklist.pop();
1286     PointsToNode::EscapeState es  = ptn->escape_state();
1287     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
1288     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
1289         es >= PointsToNode::ArgEscape) {
1290       // GlobalEscape or ArgEscape state of field means it has unknown value.
1291       if (add_edge(ptn, phantom_obj)) {
1292         // New edge was added
1293         add_field_uses_to_worklist(ptn->as_Field());
1294       }
1295     }
1296     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1297       PointsToNode* e = i.get();
1298       if (e->is_Arraycopy()) {
1299         assert(ptn->arraycopy_dst(), "sanity");
1300         // Propagate only fields escape state through arraycopy edge.
1301         if (e->fields_escape_state() < field_es) {
1302           set_fields_escape_state(e, field_es);
1303           escape_worklist.push(e);
1304         }
1305       } else if (es >= field_es) {
1306         // fields_escape_state is also set to 'es' if it is less than 'es'.
1307         if (e->escape_state() < es) {
1308           set_escape_state(e, es);
1309           escape_worklist.push(e);
1310         }
1311       } else {
1312         // Propagate field escape state.
1313         bool es_changed = false;
1314         if (e->fields_escape_state() < field_es) {
1315           set_fields_escape_state(e, field_es);
1316           es_changed = true;
1317         }
1318         if ((e->escape_state() < field_es) &&
1319             e->is_Field() && ptn->is_JavaObject() &&
1320             e->as_Field()->is_oop()) {
1321           // Change escape state of referenced fields.
1322           set_escape_state(e, field_es);
1323           es_changed = true;
1324         } else if (e->escape_state() < es) {
1325           set_escape_state(e, es);
1326           es_changed = true;
1327         }
1328         if (es_changed) {
1329           escape_worklist.push(e);
1330         }
1331       }
1332     }
1333   }
1334   // Remove escaped objects from non_escaped list.
1335   for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
1336     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1337     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
1338       non_escaped_worklist.delete_at(next);
1339     }
1340     if (ptn->escape_state() == PointsToNode::NoEscape) {
1341       // Find fields in non-escaped allocations which have unknown value.
1342       find_init_values(ptn, phantom_obj, NULL);
1343     }
1344   }
1345   return (non_escaped_worklist.length() > 0);
1346 }
1347 
1348 // Add all references to JavaObject node by walking over all uses.
1349 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
1350   int new_edges = 0;
1351   if (populate_worklist) {
1352     // Populate _worklist by uses of jobj's uses.
1353     for (UseIterator i(jobj); i.has_next(); i.next()) {
1354       PointsToNode* use = i.get();
1355       if (use->is_Arraycopy())
1356         continue;
1357       add_uses_to_worklist(use);
1358       if (use->is_Field() && use->as_Field()->is_oop()) {
1359         // Put on worklist all field's uses (loads) and
1360         // related field nodes (same base and offset).
1361         add_field_uses_to_worklist(use->as_Field());
1362       }
1363     }
1364   }
1365   for (int l = 0; l < _worklist.length(); l++) {
1366     PointsToNode* use = _worklist.at(l);
1367     if (PointsToNode::is_base_use(use)) {
1368       // Add reference from jobj to field and from field to jobj (field's base).
1369       use = PointsToNode::get_use_node(use)->as_Field();
1370       if (add_base(use->as_Field(), jobj)) {
1371         new_edges++;
1372       }
1373       continue;
1374     }
1375     assert(!use->is_JavaObject(), "sanity");
1376     if (use->is_Arraycopy()) {
1377       if (jobj == null_obj) // NULL object does not have field edges
1378         continue;
1379       // Added edge from Arraycopy node to arraycopy's source java object
1380       if (add_edge(use, jobj)) {
1381         jobj->set_arraycopy_src();
1382         new_edges++;
1383       }
1384       // and stop here.
1385       continue;
1386     }
1387     if (!add_edge(use, jobj))
1388       continue; // No new edge added, there was such edge already.
1389     new_edges++;
1390     if (use->is_LocalVar()) {
1391       add_uses_to_worklist(use);
1392       if (use->arraycopy_dst()) {
1393         for (EdgeIterator i(use); i.has_next(); i.next()) {
1394           PointsToNode* e = i.get();
1395           if (e->is_Arraycopy()) {
1396             if (jobj == null_obj) // NULL object does not have field edges
1397               continue;
1398             // Add edge from arraycopy's destination java object to Arraycopy node.
1399             if (add_edge(jobj, e)) {
1400               new_edges++;
1401               jobj->set_arraycopy_dst();
1402             }
1403           }
1404         }
1405       }
1406     } else {
1407       // Added new edge to stored in field values.
1408       // Put on worklist all field's uses (loads) and
1409       // related field nodes (same base and offset).
1410       add_field_uses_to_worklist(use->as_Field());
1411     }
1412   }
1413   _worklist.clear();
1414   _in_worklist.Reset();
1415   return new_edges;
1416 }
1417 
1418 // Put on worklist all related field nodes.
1419 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
1420   assert(field->is_oop(), "sanity");
1421   int offset = field->offset();
1422   add_uses_to_worklist(field);
1423   // Loop over all bases of this field and push on worklist Field nodes
1424   // with the same offset and base (since they may reference the same field).
1425   for (BaseIterator i(field); i.has_next(); i.next()) {
1426     PointsToNode* base = i.get();
1427     add_fields_to_worklist(field, base);
1428     // Check if the base was source object of arraycopy and go over arraycopy's
1429     // destination objects since values stored to a field of source object are
1430     // accessable by uses (loads) of fields of destination objects.
1431     if (base->arraycopy_src()) {
1432       for (UseIterator j(base); j.has_next(); j.next()) {
1433         PointsToNode* arycp = j.get();
1434         if (arycp->is_Arraycopy()) {
1435           for (UseIterator k(arycp); k.has_next(); k.next()) {
1436             PointsToNode* abase = k.get();
1437             if (abase->arraycopy_dst() && abase != base) {
1438               // Look for the same arraycopy reference.
1439               add_fields_to_worklist(field, abase);
1440             }
1441           }
1442         }
1443       }
1444     }
1445   }
1446 }
1447 
1448 // Put on worklist all related field nodes.
1449 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
1450   int offset = field->offset();
1451   if (base->is_LocalVar()) {
1452     for (UseIterator j(base); j.has_next(); j.next()) {
1453       PointsToNode* f = j.get();
1454       if (PointsToNode::is_base_use(f)) { // Field
1455         f = PointsToNode::get_use_node(f);
1456         if (f == field || !f->as_Field()->is_oop())
1457           continue;
1458         int offs = f->as_Field()->offset();
1459         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1460           add_to_worklist(f);
1461         }
1462       }
1463     }
1464   } else {
1465     assert(base->is_JavaObject(), "sanity");
1466     if (// Skip phantom_object since it is only used to indicate that
1467         // this field's content globally escapes.
1468         (base != phantom_obj) &&
1469         // NULL object node does not have fields.
1470         (base != null_obj)) {
1471       for (EdgeIterator i(base); i.has_next(); i.next()) {
1472         PointsToNode* f = i.get();
1473         // Skip arraycopy edge since store to destination object field
1474         // does not update value in source object field.
1475         if (f->is_Arraycopy()) {
1476           assert(base->arraycopy_dst(), "sanity");
1477           continue;
1478         }
1479         if (f == field || !f->as_Field()->is_oop())
1480           continue;
1481         int offs = f->as_Field()->offset();
1482         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1483           add_to_worklist(f);
1484         }
1485       }
1486     }
1487   }
1488 }
1489 
1490 // Find fields which have unknown value.
1491 int ConnectionGraph::find_field_value(FieldNode* field) {
1492   // Escaped fields should have init value already.
1493   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
1494   int new_edges = 0;
1495   for (BaseIterator i(field); i.has_next(); i.next()) {
1496     PointsToNode* base = i.get();
1497     if (base->is_JavaObject()) {
1498       // Skip Allocate's fields which will be processed later.
1499       if (base->ideal_node()->is_Allocate())
1500         return 0;
1501       assert(base == null_obj, "only NULL ptr base expected here");
1502     }
1503   }
1504   if (add_edge(field, phantom_obj)) {
1505     // New edge was added
1506     new_edges++;
1507     add_field_uses_to_worklist(field);
1508   }
1509   return new_edges;
1510 }
1511 
1512 // Find fields initializing values for allocations.
1513 int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
1514   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
1515   int new_edges = 0;
1516   Node* alloc = pta->ideal_node();
1517   if (init_val == phantom_obj) {
1518     // Do nothing for Allocate nodes since its fields values are
1519     // "known" unless they are initialized by arraycopy/clone.
1520     if (alloc->is_Allocate() && !pta->arraycopy_dst())
1521       return 0;
1522     assert(pta->arraycopy_dst() || alloc->as_CallStaticJava(), "sanity");
1523 #ifdef ASSERT
1524     if (!pta->arraycopy_dst() && alloc->as_CallStaticJava()->method() == NULL) {
1525       const char* name = alloc->as_CallStaticJava()->_name;
1526       assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
1527     }
1528 #endif
1529     // Non-escaped allocation returned from Java or runtime call have
1530     // unknown values in fields.
1531     for (EdgeIterator i(pta); i.has_next(); i.next()) {
1532       PointsToNode* field = i.get();
1533       if (field->is_Field() && field->as_Field()->is_oop()) {
1534         if (add_edge(field, phantom_obj)) {
1535           // New edge was added
1536           new_edges++;
1537           add_field_uses_to_worklist(field->as_Field());
1538         }
1539       }
1540     }
1541     return new_edges;
1542   }
1543   assert(init_val == null_obj, "sanity");
1544   // Do nothing for Call nodes since its fields values are unknown.
1545   if (!alloc->is_Allocate())
1546     return 0;
1547 
1548   InitializeNode* ini = alloc->as_Allocate()->initialization();
1549   bool visited_bottom_offset = false;
1550   GrowableArray<int> offsets_worklist;
1551 
1552   // Check if an oop field's initializing value is recorded and add
1553   // a corresponding NULL if field's value if it is not recorded.
1554   // Connection Graph does not record a default initialization by NULL
1555   // captured by Initialize node.
1556   //
1557   for (EdgeIterator i(pta); i.has_next(); i.next()) {
1558     PointsToNode* field = i.get(); // Field (AddP)
1559     if (!field->is_Field() || !field->as_Field()->is_oop())
1560       continue; // Not oop field
1561     int offset = field->as_Field()->offset();
1562     if (offset == Type::OffsetBot) {
1563       if (!visited_bottom_offset) {
1564         // OffsetBot is used to reference array's element,
1565         // always add reference to NULL to all Field nodes since we don't
1566         // known which element is referenced.
1567         if (add_edge(field, null_obj)) {
1568           // New edge was added
1569           new_edges++;
1570           add_field_uses_to_worklist(field->as_Field());
1571           visited_bottom_offset = true;
1572         }
1573       }
1574     } else {
1575       // Check only oop fields.
1576       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
1577       if (adr_type->isa_rawptr()) {
1578 #ifdef ASSERT
1579         // Raw pointers are used for initializing stores so skip it
1580         // since it should be recorded already
1581         Node* base = get_addp_base(field->ideal_node());
1582         assert(adr_type->isa_rawptr() && base->is_Proj() &&
1583                (base->in(0) == alloc),"unexpected pointer type");
1584 #endif
1585         continue;
1586       }
1587       if (!offsets_worklist.contains(offset)) {
1588         offsets_worklist.append(offset);
1589         Node* value = NULL;
1590         if (ini != NULL) {
1591           // StoreP::memory_type() == T_ADDRESS
1592           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
1593           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
1594           // Make sure initializing store has the same type as this AddP.
1595           // This AddP may reference non existing field because it is on a
1596           // dead branch of bimorphic call which is not eliminated yet.
1597           if (store != NULL && store->is_Store() &&
1598               store->as_Store()->memory_type() == ft) {
1599             value = store->in(MemNode::ValueIn);
1600 #ifdef ASSERT
1601             if (VerifyConnectionGraph) {
1602               // Verify that AddP already points to all objects the value points to.
1603               PointsToNode* val = ptnode_adr(value->_idx);
1604               assert((val != NULL), "should be processed already");
1605               PointsToNode* missed_obj = NULL;
1606               if (val->is_JavaObject()) {
1607                 if (!field->points_to(val->as_JavaObject())) {
1608                   missed_obj = val;
1609                 }
1610               } else {
1611                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
1612                   tty->print_cr("----------init store has invalid value -----");
1613                   store->dump();
1614                   val->dump();
1615                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
1616                 }
1617                 for (EdgeIterator j(val); j.has_next(); j.next()) {
1618                   PointsToNode* obj = j.get();
1619                   if (obj->is_JavaObject()) {
1620                     if (!field->points_to(obj->as_JavaObject())) {
1621                       missed_obj = obj;
1622                       break;
1623                     }
1624                   }
1625                 }
1626               }
1627               if (missed_obj != NULL) {
1628                 tty->print_cr("----------field---------------------------------");
1629                 field->dump();
1630                 tty->print_cr("----------missed referernce to object-----------");
1631                 missed_obj->dump();
1632                 tty->print_cr("----------object referernced by init store -----");
1633                 store->dump();
1634                 val->dump();
1635                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
1636               }
1637             }
1638 #endif
1639           } else {
1640             // There could be initializing stores which follow allocation.
1641             // For example, a volatile field store is not collected
1642             // by Initialize node.
1643             //
1644             // Need to check for dependent loads to separate such stores from
1645             // stores which follow loads. For now, add initial value NULL so
1646             // that compare pointers optimization works correctly.
1647           }
1648         }
1649         if (value == NULL) {
1650           // A field's initializing value was not recorded. Add NULL.
1651           if (add_edge(field, null_obj)) {
1652             // New edge was added
1653             new_edges++;
1654             add_field_uses_to_worklist(field->as_Field());
1655           }
1656         }
1657       }
1658     }
1659   }
1660   return new_edges;
1661 }
1662 
1663 // Adjust scalar_replaceable state after Connection Graph is built.
1664 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
1665   // Search for non-escaping objects which are not scalar replaceable
1666   // and mark them to propagate the state to referenced objects.
1667 
1668   // 1. An object is not scalar replaceable if the field into which it is
1669   // stored has unknown offset (stored into unknown element of an array).
1670   //
1671   for (UseIterator i(jobj); i.has_next(); i.next()) {
1672     PointsToNode* use = i.get();
1673     if (use->is_Arraycopy()) {
1674       continue;
1675     }
1676     if (use->is_Field()) {
1677       FieldNode* field = use->as_Field();
1678       assert(field->is_oop() && field->scalar_replaceable(), "sanity");
1679       if (field->offset() == Type::OffsetBot) {
1680         jobj->set_scalar_replaceable(false);
1681         return;
1682       }
1683       // 2. An object is not scalar replaceable if the field into which it is
1684       // stored has multiple bases one of which is null.
1685       if (field->base_count() > 1) {
1686         for (BaseIterator i(field); i.has_next(); i.next()) {
1687           PointsToNode* base = i.get();
1688           if (base == null_obj) {
1689             jobj->set_scalar_replaceable(false);
1690             return;
1691           }
1692         }
1693       }
1694     }
1695     assert(use->is_Field() || use->is_LocalVar(), "sanity");
1696     // 3. An object is not scalar replaceable if it is merged with other objects.
1697     for (EdgeIterator j(use); j.has_next(); j.next()) {
1698       PointsToNode* ptn = j.get();
1699       if (ptn->is_JavaObject() && ptn != jobj) {
1700         // Mark all objects.
1701         jobj->set_scalar_replaceable(false);
1702          ptn->set_scalar_replaceable(false);
1703       }
1704     }
1705     if (!jobj->scalar_replaceable()) {
1706       return;
1707     }
1708   }
1709 
1710   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
1711     if (j.get()->is_Arraycopy()) {
1712       continue;
1713     }
1714 
1715     // Non-escaping object node should point only to field nodes.
1716     FieldNode* field = j.get()->as_Field();
1717     int offset = field->as_Field()->offset();
1718 
1719     // 4. An object is not scalar replaceable if it has a field with unknown
1720     // offset (array's element is accessed in loop).
1721     if (offset == Type::OffsetBot) {
1722       jobj->set_scalar_replaceable(false);
1723       return;
1724     }
1725     // 5. Currently an object is not scalar replaceable if a LoadStore node
1726     // access its field since the field value is unknown after it.
1727     //
1728     Node* n = field->ideal_node();
1729     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1730       if (n->fast_out(i)->is_LoadStore()) {
1731         jobj->set_scalar_replaceable(false);
1732         return;
1733       }
1734     }
1735 
1736     // 6. Or the address may point to more then one object. This may produce
1737     // the false positive result (set not scalar replaceable)
1738     // since the flow-insensitive escape analysis can't separate
1739     // the case when stores overwrite the field's value from the case
1740     // when stores happened on different control branches.
1741     //
1742     // Note: it will disable scalar replacement in some cases:
1743     //
1744     //    Point p[] = new Point[1];
1745     //    p[0] = new Point(); // Will be not scalar replaced
1746     //
1747     // but it will save us from incorrect optimizations in next cases:
1748     //
1749     //    Point p[] = new Point[1];
1750     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
1751     //
1752     if (field->base_count() > 1) {
1753       for (BaseIterator i(field); i.has_next(); i.next()) {
1754         PointsToNode* base = i.get();
1755         // Don't take into account LocalVar nodes which
1756         // may point to only one object which should be also
1757         // this field's base by now.
1758         if (base->is_JavaObject() && base != jobj) {
1759           // Mark all bases.
1760           jobj->set_scalar_replaceable(false);
1761           base->set_scalar_replaceable(false);
1762         }
1763       }
1764     }
1765   }
1766 }
1767 
1768 #ifdef ASSERT
1769 void ConnectionGraph::verify_connection_graph(
1770                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1771                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1772                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1773                          GrowableArray<Node*>& addp_worklist) {
1774   // Verify that graph is complete - no new edges could be added.
1775   int java_objects_length = java_objects_worklist.length();
1776   int non_escaped_length  = non_escaped_worklist.length();
1777   int new_edges = 0;
1778   for (int next = 0; next < java_objects_length; ++next) {
1779     JavaObjectNode* ptn = java_objects_worklist.at(next);
1780     new_edges += add_java_object_edges(ptn, true);
1781   }
1782   assert(new_edges == 0, "graph was not complete");
1783   // Verify that escape state is final.
1784   int length = non_escaped_worklist.length();
1785   find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
1786   assert((non_escaped_length == non_escaped_worklist.length()) &&
1787          (non_escaped_length == length) &&
1788          (_worklist.length() == 0), "escape state was not final");
1789 
1790   // Verify fields information.
1791   int addp_length = addp_worklist.length();
1792   for (int next = 0; next < addp_length; ++next ) {
1793     Node* n = addp_worklist.at(next);
1794     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
1795     if (field->is_oop()) {
1796       // Verify that field has all bases
1797       Node* base = get_addp_base(n);
1798       PointsToNode* ptn = ptnode_adr(base->_idx);
1799       if (ptn->is_JavaObject()) {
1800         assert(field->has_base(ptn->as_JavaObject()), "sanity");
1801       } else {
1802         assert(ptn->is_LocalVar(), "sanity");
1803         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1804           PointsToNode* e = i.get();
1805           if (e->is_JavaObject()) {
1806             assert(field->has_base(e->as_JavaObject()), "sanity");
1807           }
1808         }
1809       }
1810       // Verify that all fields have initializing values.
1811       if (field->edge_count() == 0) {
1812         tty->print_cr("----------field does not have references----------");
1813         field->dump();
1814         for (BaseIterator i(field); i.has_next(); i.next()) {
1815           PointsToNode* base = i.get();
1816           tty->print_cr("----------field has next base---------------------");
1817           base->dump();
1818           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
1819             tty->print_cr("----------base has fields-------------------------");
1820             for (EdgeIterator j(base); j.has_next(); j.next()) {
1821               j.get()->dump();
1822             }
1823             tty->print_cr("----------base has references---------------------");
1824             for (UseIterator j(base); j.has_next(); j.next()) {
1825               j.get()->dump();
1826             }
1827           }
1828         }
1829         for (UseIterator i(field); i.has_next(); i.next()) {
1830           i.get()->dump();
1831         }
1832         assert(field->edge_count() > 0, "sanity");
1833       }
1834     }
1835   }
1836 }
1837 #endif
1838 
1839 // Optimize ideal graph.
1840 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
1841                                            GrowableArray<Node*>& storestore_worklist) {
1842   Compile* C = _compile;
1843   PhaseIterGVN* igvn = _igvn;
1844   if (EliminateLocks) {
1845     // Mark locks before changing ideal graph.
1846     int cnt = C->macro_count();
1847     for( int i=0; i < cnt; i++ ) {
1848       Node *n = C->macro_node(i);
1849       if (n->is_AbstractLock()) { // Lock and Unlock nodes
1850         AbstractLockNode* alock = n->as_AbstractLock();
1851         if (!alock->is_non_esc_obj()) {
1852           if (not_global_escape(alock->obj_node())) {
1853             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
1854             // The lock could be marked eliminated by lock coarsening
1855             // code during first IGVN before EA. Replace coarsened flag
1856             // to eliminate all associated locks/unlocks.
1857 #ifdef ASSERT
1858             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
1859 #endif
1860             alock->set_non_esc_obj();
1861           }
1862         }
1863       }
1864     }
1865   }
1866 
1867   if (OptimizePtrCompare) {
1868     // Add ConI(#CC_GT) and ConI(#CC_EQ).
1869     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);
1870     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
1871     // Optimize objects compare.
1872     while (ptr_cmp_worklist.length() != 0) {
1873       Node *n = ptr_cmp_worklist.pop();
1874       Node *res = optimize_ptr_compare(n);
1875       if (res != NULL) {
1876 #ifndef PRODUCT
1877         if (PrintOptimizePtrCompare) {
1878           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"));
1879           if (Verbose) {
1880             n->dump(1);
1881           }
1882         }
1883 #endif
1884         igvn->replace_node(n, res);
1885       }
1886     }
1887     // cleanup
1888     if (_pcmp_neq->outcnt() == 0)
1889       igvn->hash_delete(_pcmp_neq);
1890     if (_pcmp_eq->outcnt()  == 0)
1891       igvn->hash_delete(_pcmp_eq);
1892   }
1893 
1894   // For MemBarStoreStore nodes added in library_call.cpp, check
1895   // escape status of associated AllocateNode and optimize out
1896   // MemBarStoreStore node if the allocated object never escapes.
1897   while (storestore_worklist.length() != 0) {
1898     Node *n = storestore_worklist.pop();
1899     MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
1900     Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
1901     assert (alloc->is_Allocate(), "storestore should point to AllocateNode");
1902     if (not_global_escape(alloc)) {
1903       MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
1904       mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
1905       mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
1906       igvn->register_new_node_with_optimizer(mb);
1907       igvn->replace_node(storestore, mb);
1908     }
1909   }
1910 }
1911 
1912 // Optimize objects compare.
1913 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
1914   assert(OptimizePtrCompare, "sanity");
1915   PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
1916   PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
1917   JavaObjectNode* jobj1 = unique_java_object(n->in(1));
1918   JavaObjectNode* jobj2 = unique_java_object(n->in(2));
1919   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
1920   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
1921 
1922   // Check simple cases first.
1923   if (jobj1 != NULL) {
1924     if (jobj1->escape_state() == PointsToNode::NoEscape) {
1925       if (jobj1 == jobj2) {
1926         // Comparing the same not escaping object.
1927         return _pcmp_eq;
1928       }
1929       Node* obj = jobj1->ideal_node();
1930       // Comparing not escaping allocation.
1931       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1932           !ptn2->points_to(jobj1)) {
1933         return _pcmp_neq; // This includes nullness check.
1934       }
1935     }
1936   }
1937   if (jobj2 != NULL) {
1938     if (jobj2->escape_state() == PointsToNode::NoEscape) {
1939       Node* obj = jobj2->ideal_node();
1940       // Comparing not escaping allocation.
1941       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1942           !ptn1->points_to(jobj2)) {
1943         return _pcmp_neq; // This includes nullness check.
1944       }
1945     }
1946   }
1947   if (jobj1 != NULL && jobj1 != phantom_obj &&
1948       jobj2 != NULL && jobj2 != phantom_obj &&
1949       jobj1->ideal_node()->is_Con() &&
1950       jobj2->ideal_node()->is_Con()) {
1951     // Klass or String constants compare. Need to be careful with
1952     // compressed pointers - compare types of ConN and ConP instead of nodes.
1953     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
1954     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
1955     if (t1->make_ptr() == t2->make_ptr()) {
1956       return _pcmp_eq;
1957     } else {
1958       return _pcmp_neq;
1959     }
1960   }
1961   if (ptn1->meet(ptn2)) {
1962     return NULL; // Sets are not disjoint
1963   }
1964 
1965   // Sets are disjoint.
1966   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
1967   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
1968   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
1969   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
1970   if (set1_has_unknown_ptr && set2_has_null_ptr ||
1971       set2_has_unknown_ptr && set1_has_null_ptr) {
1972     // Check nullness of unknown object.
1973     return NULL;
1974   }
1975 
1976   // Disjointness by itself is not sufficient since
1977   // alias analysis is not complete for escaped objects.
1978   // Disjoint sets are definitely unrelated only when
1979   // at least one set has only not escaping allocations.
1980   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
1981     if (ptn1->non_escaping_allocation()) {
1982       return _pcmp_neq;
1983     }
1984   }
1985   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
1986     if (ptn2->non_escaping_allocation()) {
1987       return _pcmp_neq;
1988     }
1989   }
1990   return NULL;
1991 }
1992 
1993 // Connection Graph constuction functions.
1994 
1995 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
1996   PointsToNode* ptadr = _nodes.at(n->_idx);
1997   if (ptadr != NULL) {
1998     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
1999     return;
2000   }
2001   Compile* C = _compile;
2002   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
2003   _nodes.at_put(n->_idx, ptadr);
2004 }
2005 
2006 void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
2007   PointsToNode* ptadr = _nodes.at(n->_idx);
2008   if (ptadr != NULL) {
2009     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
2010     return;
2011   }
2012   Compile* C = _compile;
2013   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
2014   _nodes.at_put(n->_idx, ptadr);
2015 }
2016 
2017 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
2018   PointsToNode* ptadr = _nodes.at(n->_idx);
2019   if (ptadr != NULL) {
2020     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
2021     return;
2022   }
2023   bool unsafe = false;
2024   bool is_oop = is_oop_field(n, offset, &unsafe);
2025   if (unsafe) {
2026     es = PointsToNode::GlobalEscape;
2027   }
2028   Compile* C = _compile;
2029   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
2030   _nodes.at_put(n->_idx, field);
2031 }
2032 
2033 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
2034                                     PointsToNode* src, PointsToNode* dst) {
2035   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
2036   assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
2037   PointsToNode* ptadr = _nodes.at(n->_idx);
2038   if (ptadr != NULL) {
2039     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
2040     return;
2041   }
2042   Compile* C = _compile;
2043   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
2044   _nodes.at_put(n->_idx, ptadr);
2045   // Add edge from arraycopy node to source object.
2046   (void)add_edge(ptadr, src);
2047   src->set_arraycopy_src();
2048   // Add edge from destination object to arraycopy node.
2049   (void)add_edge(dst, ptadr);
2050   dst->set_arraycopy_dst();
2051 }
2052 
2053 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
2054   const Type* adr_type = n->as_AddP()->bottom_type();
2055   int field_offset = adr_type->isa_aryptr() ? adr_type->isa_aryptr()->field_offset().get() : Type::OffsetBot;
2056   BasicType bt = T_INT;
2057   if (offset == Type::OffsetBot && field_offset == Type::OffsetBot) {
2058     // Check only oop fields.
2059     if (!adr_type->isa_aryptr() ||
2060         (adr_type->isa_aryptr()->klass() == NULL) ||
2061          adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
2062       // OffsetBot is used to reference array's element. Ignore first AddP.
2063       if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
2064         bt = T_OBJECT;
2065       }
2066     }
2067   } else if (offset != oopDesc::klass_offset_in_bytes()) {
2068     if (adr_type->isa_instptr() || adr_type->isa_valuetypeptr()) {
2069       ciField* field = _compile->alias_type(adr_type->is_ptr())->field();
2070       if (field != NULL) {
2071         bt = field->layout_type();
2072       } else {
2073         // Check for unsafe oop field access
2074         if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
2075           bt = T_OBJECT;
2076           (*unsafe) = true;
2077         }
2078       }
2079     } else if (adr_type->isa_aryptr()) {
2080       if (offset == arrayOopDesc::length_offset_in_bytes()) {
2081         // Ignore array length load.
2082       } else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
2083         // Ignore first AddP.
2084       } else {
2085         const Type* elemtype = adr_type->isa_aryptr()->elem();
2086         if (elemtype->isa_valuetype()) {
2087           assert(field_offset != Type::OffsetBot, "invalid field offset");
2088           ciValueKlass* vk = elemtype->is_valuetype()->value_klass();
2089           field_offset += vk->first_field_offset();
2090           bt = vk->get_field_by_offset(field_offset, false)->layout_type();
2091         } else {
2092           bt = elemtype->array_element_basic_type();
2093         }
2094       }
2095     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
2096       // Allocation initialization, ThreadLocal field access, unsafe access
2097       if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
2098         bt = T_OBJECT;
2099       }
2100     }
2101   }
2102   return (bt == T_OBJECT || bt == T_NARROWOOP || bt == T_ARRAY);
2103 }
2104 
2105 // Returns unique pointed java object or NULL.
2106 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
2107   assert(!_collecting, "should not call when contructed graph");
2108   // If the node was created after the escape computation we can't answer.
2109   uint idx = n->_idx;
2110   if (idx >= nodes_size()) {
2111     return NULL;
2112   }
2113   PointsToNode* ptn = ptnode_adr(idx);
2114   if (ptn->is_JavaObject()) {
2115     return ptn->as_JavaObject();
2116   }
2117   assert(ptn->is_LocalVar(), "sanity");
2118   // Check all java objects it points to.
2119   JavaObjectNode* jobj = NULL;
2120   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2121     PointsToNode* e = i.get();
2122     if (e->is_JavaObject()) {
2123       if (jobj == NULL) {
2124         jobj = e->as_JavaObject();
2125       } else if (jobj != e) {
2126         return NULL;
2127       }
2128     }
2129   }
2130   return jobj;
2131 }
2132 
2133 // Return true if this node points only to non-escaping allocations.
2134 bool PointsToNode::non_escaping_allocation() {
2135   if (is_JavaObject()) {
2136     Node* n = ideal_node();
2137     if (n->is_Allocate() || n->is_CallStaticJava()) {
2138       return (escape_state() == PointsToNode::NoEscape);
2139     } else {
2140       return false;
2141     }
2142   }
2143   assert(is_LocalVar(), "sanity");
2144   // Check all java objects it points to.
2145   for (EdgeIterator i(this); i.has_next(); i.next()) {
2146     PointsToNode* e = i.get();
2147     if (e->is_JavaObject()) {
2148       Node* n = e->ideal_node();
2149       if ((e->escape_state() != PointsToNode::NoEscape) ||
2150           !(n->is_Allocate() || n->is_CallStaticJava())) {
2151         return false;
2152       }
2153     }
2154   }
2155   return true;
2156 }
2157 
2158 // Return true if we know the node does not escape globally.
2159 bool ConnectionGraph::not_global_escape(Node *n) {
2160   assert(!_collecting, "should not call during graph construction");
2161   // If the node was created after the escape computation we can't answer.
2162   uint idx = n->_idx;
2163   if (idx >= nodes_size()) {
2164     return false;
2165   }
2166   PointsToNode* ptn = ptnode_adr(idx);
2167   PointsToNode::EscapeState es = ptn->escape_state();
2168   // If we have already computed a value, return it.
2169   if (es >= PointsToNode::GlobalEscape)
2170     return false;
2171   if (ptn->is_JavaObject()) {
2172     return true; // (es < PointsToNode::GlobalEscape);
2173   }
2174   assert(ptn->is_LocalVar(), "sanity");
2175   // Check all java objects it points to.
2176   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2177     if (i.get()->escape_state() >= PointsToNode::GlobalEscape)
2178       return false;
2179   }
2180   return true;
2181 }
2182 
2183 
2184 // Helper functions
2185 
2186 // Return true if this node points to specified node or nodes it points to.
2187 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
2188   if (is_JavaObject()) {
2189     return (this == ptn);
2190   }
2191   assert(is_LocalVar() || is_Field(), "sanity");
2192   for (EdgeIterator i(this); i.has_next(); i.next()) {
2193     if (i.get() == ptn)
2194       return true;
2195   }
2196   return false;
2197 }
2198 
2199 // Return true if one node points to an other.
2200 bool PointsToNode::meet(PointsToNode* ptn) {
2201   if (this == ptn) {
2202     return true;
2203   } else if (ptn->is_JavaObject()) {
2204     return this->points_to(ptn->as_JavaObject());
2205   } else if (this->is_JavaObject()) {
2206     return ptn->points_to(this->as_JavaObject());
2207   }
2208   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
2209   int ptn_count =  ptn->edge_count();
2210   for (EdgeIterator i(this); i.has_next(); i.next()) {
2211     PointsToNode* this_e = i.get();
2212     for (int j = 0; j < ptn_count; j++) {
2213       if (this_e == ptn->edge(j))
2214         return true;
2215     }
2216   }
2217   return false;
2218 }
2219 
2220 #ifdef ASSERT
2221 // Return true if bases point to this java object.
2222 bool FieldNode::has_base(JavaObjectNode* jobj) const {
2223   for (BaseIterator i(this); i.has_next(); i.next()) {
2224     if (i.get() == jobj)
2225       return true;
2226   }
2227   return false;
2228 }
2229 #endif
2230 
2231 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
2232   const Type *adr_type = phase->type(adr);
2233   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
2234       adr->in(AddPNode::Address)->is_Proj() &&
2235       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
2236     // We are computing a raw address for a store captured by an Initialize
2237     // compute an appropriate address type. AddP cases #3 and #5 (see below).
2238     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
2239     assert(offs != Type::OffsetBot ||
2240            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
2241            "offset must be a constant or it is initialization of array");
2242     return offs;
2243   }
2244   const TypePtr *t_ptr = adr_type->isa_ptr();
2245   assert(t_ptr != NULL, "must be a pointer type");
2246   return t_ptr->offset();
2247 }
2248 
2249 Node* ConnectionGraph::get_addp_base(Node *addp) {
2250   assert(addp->is_AddP(), "must be AddP");
2251   //
2252   // AddP cases for Base and Address inputs:
2253   // case #1. Direct object's field reference:
2254   //     Allocate
2255   //       |
2256   //     Proj #5 ( oop result )
2257   //       |
2258   //     CheckCastPP (cast to instance type)
2259   //      | |
2260   //     AddP  ( base == address )
2261   //
2262   // case #2. Indirect object's field reference:
2263   //      Phi
2264   //       |
2265   //     CastPP (cast to instance type)
2266   //      | |
2267   //     AddP  ( base == address )
2268   //
2269   // case #3. Raw object's field reference for Initialize node:
2270   //      Allocate
2271   //        |
2272   //      Proj #5 ( oop result )
2273   //  top   |
2274   //     \  |
2275   //     AddP  ( base == top )
2276   //
2277   // case #4. Array's element reference:
2278   //   {CheckCastPP | CastPP}
2279   //     |  | |
2280   //     |  AddP ( array's element offset )
2281   //     |  |
2282   //     AddP ( array's offset )
2283   //
2284   // case #5. Raw object's field reference for arraycopy stub call:
2285   //          The inline_native_clone() case when the arraycopy stub is called
2286   //          after the allocation before Initialize and CheckCastPP nodes.
2287   //      Allocate
2288   //        |
2289   //      Proj #5 ( oop result )
2290   //       | |
2291   //       AddP  ( base == address )
2292   //
2293   // case #6. Constant Pool, ThreadLocal, CastX2P or
2294   //          Raw object's field reference:
2295   //      {ConP, ThreadLocal, CastX2P, raw Load}
2296   //  top   |
2297   //     \  |
2298   //     AddP  ( base == top )
2299   //
2300   // case #7. Klass's field reference.
2301   //      LoadKlass
2302   //       | |
2303   //       AddP  ( base == address )
2304   //
2305   // case #8. narrow Klass's field reference.
2306   //      LoadNKlass
2307   //       |
2308   //      DecodeN
2309   //       | |
2310   //       AddP  ( base == address )
2311   //
2312   Node *base = addp->in(AddPNode::Base);
2313   if (base->uncast()->is_top()) { // The AddP case #3 and #6.
2314     base = addp->in(AddPNode::Address);
2315     while (base->is_AddP()) {
2316       // Case #6 (unsafe access) may have several chained AddP nodes.
2317       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
2318       base = base->in(AddPNode::Address);
2319     }
2320     Node* uncast_base = base->uncast();
2321     int opcode = uncast_base->Opcode();
2322     assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
2323            opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
2324            (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
2325            (uncast_base->is_Proj() && uncast_base->in(0)->is_Allocate()), "sanity");
2326   }
2327   return base;
2328 }
2329 
2330 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
2331   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
2332   Node* addp2 = addp->raw_out(0);
2333   if (addp->outcnt() == 1 && addp2->is_AddP() &&
2334       addp2->in(AddPNode::Base) == n &&
2335       addp2->in(AddPNode::Address) == addp) {
2336     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
2337     //
2338     // Find array's offset to push it on worklist first and
2339     // as result process an array's element offset first (pushed second)
2340     // to avoid CastPP for the array's offset.
2341     // Otherwise the inserted CastPP (LocalVar) will point to what
2342     // the AddP (Field) points to. Which would be wrong since
2343     // the algorithm expects the CastPP has the same point as
2344     // as AddP's base CheckCastPP (LocalVar).
2345     //
2346     //    ArrayAllocation
2347     //     |
2348     //    CheckCastPP
2349     //     |
2350     //    memProj (from ArrayAllocation CheckCastPP)
2351     //     |  ||
2352     //     |  ||   Int (element index)
2353     //     |  ||    |   ConI (log(element size))
2354     //     |  ||    |   /
2355     //     |  ||   LShift
2356     //     |  ||  /
2357     //     |  AddP (array's element offset)
2358     //     |  |
2359     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
2360     //     | / /
2361     //     AddP (array's offset)
2362     //      |
2363     //     Load/Store (memory operation on array's element)
2364     //
2365     return addp2;
2366   }
2367   return NULL;
2368 }
2369 
2370 //
2371 // Adjust the type and inputs of an AddP which computes the
2372 // address of a field of an instance
2373 //
2374 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
2375   PhaseGVN* igvn = _igvn;
2376   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
2377   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
2378   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
2379   if (t == NULL) {
2380     // We are computing a raw address for a store captured by an Initialize
2381     // compute an appropriate address type (cases #3 and #5).
2382     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
2383     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
2384     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
2385     assert(offs != Type::OffsetBot, "offset must be a constant");
2386     t = base_t->add_offset(offs)->is_oopptr();
2387   }
2388   int inst_id = base_t->instance_id();
2389   assert(!t->is_known_instance() || t->instance_id() == inst_id,
2390                              "old type must be non-instance or match new type");
2391 
2392   // The type 't' could be subclass of 'base_t'.
2393   // As result t->offset() could be large then base_t's size and it will
2394   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
2395   // constructor verifies correctness of the offset.
2396   //
2397   // It could happened on subclass's branch (from the type profiling
2398   // inlining) which was not eliminated during parsing since the exactness
2399   // of the allocation type was not propagated to the subclass type check.
2400   //
2401   // Or the type 't' could be not related to 'base_t' at all.
2402   // It could happened when CHA type is different from MDO type on a dead path
2403   // (for example, from instanceof check) which is not collapsed during parsing.
2404   //
2405   // Do nothing for such AddP node and don't process its users since
2406   // this code branch will go away.
2407   //
2408   if (!t->is_known_instance() &&
2409       !base_t->klass()->is_subtype_of(t->klass())) {
2410      return false; // bail out
2411   }
2412   const TypePtr* tinst = base_t->add_offset(t->offset());
2413   if (tinst->isa_aryptr() && t->isa_aryptr()) {
2414     // In the case of a flattened value type array, each field has its
2415     // own slice so we need to keep track of the field being accessed.
2416     tinst = tinst->is_aryptr()->with_field_offset(t->is_aryptr()->field_offset().get());
2417   }
2418 
2419   // Do NOT remove the next line: ensure a new alias index is allocated
2420   // for the instance type. Note: C++ will not remove it since the call
2421   // has side effect.
2422   int alias_idx = _compile->get_alias_index(tinst);
2423   igvn->set_type(addp, tinst);
2424   // record the allocation in the node map
2425   set_map(addp, get_map(base->_idx));
2426   // Set addp's Base and Address to 'base'.
2427   Node *abase = addp->in(AddPNode::Base);
2428   Node *adr   = addp->in(AddPNode::Address);
2429   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
2430       adr->in(0)->_idx == (uint)inst_id) {
2431     // Skip AddP cases #3 and #5.
2432   } else {
2433     assert(!abase->is_top(), "sanity"); // AddP case #3
2434     if (abase != base) {
2435       igvn->hash_delete(addp);
2436       addp->set_req(AddPNode::Base, base);
2437       if (abase == adr) {
2438         addp->set_req(AddPNode::Address, base);
2439       } else {
2440         // AddP case #4 (adr is array's element offset AddP node)
2441 #ifdef ASSERT
2442         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
2443         assert(adr->is_AddP() && atype != NULL &&
2444                atype->instance_id() == inst_id, "array's element offset should be processed first");
2445 #endif
2446       }
2447       igvn->hash_insert(addp);
2448     }
2449   }
2450   // Put on IGVN worklist since at least addp's type was changed above.
2451   record_for_optimizer(addp);
2452   return true;
2453 }
2454 
2455 //
2456 // Create a new version of orig_phi if necessary. Returns either the newly
2457 // created phi or an existing phi.  Sets create_new to indicate whether a new
2458 // phi was created.  Cache the last newly created phi in the node map.
2459 //
2460 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
2461   Compile *C = _compile;
2462   PhaseGVN* igvn = _igvn;
2463   new_created = false;
2464   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
2465   // nothing to do if orig_phi is bottom memory or matches alias_idx
2466   if (phi_alias_idx == alias_idx) {
2467     return orig_phi;
2468   }
2469   // Have we recently created a Phi for this alias index?
2470   PhiNode *result = get_map_phi(orig_phi->_idx);
2471   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
2472     return result;
2473   }
2474   // Previous check may fail when the same wide memory Phi was split into Phis
2475   // for different memory slices. Search all Phis for this region.
2476   if (result != NULL) {
2477     Node* region = orig_phi->in(0);
2478     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
2479       Node* phi = region->fast_out(i);
2480       if (phi->is_Phi() &&
2481           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
2482         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
2483         return phi->as_Phi();
2484       }
2485     }
2486   }
2487   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
2488     if (C->do_escape_analysis() == true && !C->failing()) {
2489       // Retry compilation without escape analysis.
2490       // If this is the first failure, the sentinel string will "stick"
2491       // to the Compile object, and the C2Compiler will see it and retry.
2492       C->record_failure(C2Compiler::retry_no_escape_analysis());
2493     }
2494     return NULL;
2495   }
2496   orig_phi_worklist.append_if_missing(orig_phi);
2497   const TypePtr *atype = C->get_adr_type(alias_idx);
2498   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
2499   C->copy_node_notes_to(result, orig_phi);
2500   igvn->set_type(result, result->bottom_type());
2501   record_for_optimizer(result);
2502   set_map(orig_phi, result);
2503   new_created = true;
2504   return result;
2505 }
2506 
2507 //
2508 // Return a new version of Memory Phi "orig_phi" with the inputs having the
2509 // specified alias index.
2510 //
2511 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist) {
2512   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
2513   Compile *C = _compile;
2514   PhaseGVN* igvn = _igvn;
2515   bool new_phi_created;
2516   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
2517   if (!new_phi_created) {
2518     return result;
2519   }
2520   GrowableArray<PhiNode *>  phi_list;
2521   GrowableArray<uint>  cur_input;
2522   PhiNode *phi = orig_phi;
2523   uint idx = 1;
2524   bool finished = false;
2525   while(!finished) {
2526     while (idx < phi->req()) {
2527       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist);
2528       if (mem != NULL && mem->is_Phi()) {
2529         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
2530         if (new_phi_created) {
2531           // found an phi for which we created a new split, push current one on worklist and begin
2532           // processing new one
2533           phi_list.push(phi);
2534           cur_input.push(idx);
2535           phi = mem->as_Phi();
2536           result = newphi;
2537           idx = 1;
2538           continue;
2539         } else {
2540           mem = newphi;
2541         }
2542       }
2543       if (C->failing()) {
2544         return NULL;
2545       }
2546       result->set_req(idx++, mem);
2547     }
2548 #ifdef ASSERT
2549     // verify that the new Phi has an input for each input of the original
2550     assert( phi->req() == result->req(), "must have same number of inputs.");
2551     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
2552 #endif
2553     // Check if all new phi's inputs have specified alias index.
2554     // Otherwise use old phi.
2555     for (uint i = 1; i < phi->req(); i++) {
2556       Node* in = result->in(i);
2557       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
2558     }
2559     // we have finished processing a Phi, see if there are any more to do
2560     finished = (phi_list.length() == 0 );
2561     if (!finished) {
2562       phi = phi_list.pop();
2563       idx = cur_input.pop();
2564       PhiNode *prev_result = get_map_phi(phi->_idx);
2565       prev_result->set_req(idx++, result);
2566       result = prev_result;
2567     }
2568   }
2569   return result;
2570 }
2571 
2572 //
2573 // The next methods are derived from methods in MemNode.
2574 //
2575 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
2576   Node *mem = mmem;
2577   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
2578   // means an array I have not precisely typed yet.  Do not do any
2579   // alias stuff with it any time soon.
2580   if (toop->base() != Type::AnyPtr &&
2581       !(toop->klass() != NULL &&
2582         toop->klass()->is_java_lang_Object() &&
2583         toop->offset() == Type::OffsetBot)) {
2584     mem = mmem->memory_at(alias_idx);
2585     // Update input if it is progress over what we have now
2586   }
2587   return mem;
2588 }
2589 
2590 //
2591 // Move memory users to their memory slices.
2592 //
2593 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
2594   Compile* C = _compile;
2595   PhaseGVN* igvn = _igvn;
2596   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
2597   assert(tp != NULL, "ptr type");
2598   int alias_idx = C->get_alias_index(tp);
2599   int general_idx = C->get_general_index(alias_idx);
2600 
2601   // Move users first
2602   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2603     Node* use = n->fast_out(i);
2604     if (use->is_MergeMem()) {
2605       MergeMemNode* mmem = use->as_MergeMem();
2606       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
2607       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
2608         continue; // Nothing to do
2609       }
2610       // Replace previous general reference to mem node.
2611       uint orig_uniq = C->unique();
2612       Node* m = find_inst_mem(n, general_idx, orig_phis);
2613       assert(orig_uniq == C->unique(), "no new nodes");
2614       mmem->set_memory_at(general_idx, m);
2615       --imax;
2616       --i;
2617     } else if (use->is_MemBar()) {
2618       assert(!use->is_Initialize(), "initializing stores should not be moved");
2619       if (use->req() > MemBarNode::Precedent &&
2620           use->in(MemBarNode::Precedent) == n) {
2621         // Don't move related membars.
2622         record_for_optimizer(use);
2623         continue;
2624       }
2625       tp = use->as_MemBar()->adr_type()->isa_ptr();
2626       if (tp != NULL && C->get_alias_index(tp) == alias_idx ||
2627           alias_idx == general_idx) {
2628         continue; // Nothing to do
2629       }
2630       // Move to general memory slice.
2631       uint orig_uniq = C->unique();
2632       Node* m = find_inst_mem(n, general_idx, orig_phis);
2633       assert(orig_uniq == C->unique(), "no new nodes");
2634       igvn->hash_delete(use);
2635       imax -= use->replace_edge(n, m);
2636       igvn->hash_insert(use);
2637       record_for_optimizer(use);
2638       --i;
2639 #ifdef ASSERT
2640     } else if (use->is_Mem()) {
2641       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
2642         // Don't move related cardmark.
2643         continue;
2644       }
2645       // Memory nodes should have new memory input.
2646       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
2647       assert(tp != NULL, "ptr type");
2648       int idx = C->get_alias_index(tp);
2649       assert(get_map(use->_idx) != NULL || idx == alias_idx,
2650              "Following memory nodes should have new memory input or be on the same memory slice");
2651     } else if (use->is_Phi()) {
2652       // Phi nodes should be split and moved already.
2653       tp = use->as_Phi()->adr_type()->isa_ptr();
2654       assert(tp != NULL, "ptr type");
2655       int idx = C->get_alias_index(tp);
2656       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
2657     } else {
2658       use->dump();
2659       assert(false, "should not be here");
2660 #endif
2661     }
2662   }
2663 }
2664 
2665 //
2666 // Search memory chain of "mem" to find a MemNode whose address
2667 // is the specified alias index.
2668 //
2669 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis) {
2670   if (orig_mem == NULL)
2671     return orig_mem;
2672   Compile* C = _compile;
2673   PhaseGVN* igvn = _igvn;
2674   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
2675   bool is_instance = (toop != NULL) && toop->is_known_instance();
2676   Node *start_mem = C->start()->proj_out(TypeFunc::Memory);
2677   Node *prev = NULL;
2678   Node *result = orig_mem;
2679   while (prev != result) {
2680     prev = result;
2681     if (result == start_mem)
2682       break;  // hit one of our sentinels
2683     if (result->is_Mem()) {
2684       const Type *at = igvn->type(result->in(MemNode::Address));
2685       if (at == Type::TOP)
2686         break; // Dead
2687       assert (at->isa_ptr() != NULL, "pointer type required.");
2688       int idx = C->get_alias_index(at->is_ptr());
2689       if (idx == alias_idx)
2690         break; // Found
2691       if (!is_instance && (at->isa_oopptr() == NULL ||
2692                            !at->is_oopptr()->is_known_instance())) {
2693         break; // Do not skip store to general memory slice.
2694       }
2695       result = result->in(MemNode::Memory);
2696     }
2697     if (!is_instance)
2698       continue;  // don't search further for non-instance types
2699     // skip over a call which does not affect this memory slice
2700     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
2701       Node *proj_in = result->in(0);
2702       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
2703         break;  // hit one of our sentinels
2704       } else if (proj_in->is_Call()) {
2705         // ArrayCopy node processed here as well
2706         CallNode *call = proj_in->as_Call();
2707         if (!call->may_modify(toop, igvn)) {
2708           result = call->in(TypeFunc::Memory);
2709         }
2710       } else if (proj_in->is_Initialize()) {
2711         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
2712         // Stop if this is the initialization for the object instance which
2713         // which contains this memory slice, otherwise skip over it.
2714         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
2715           result = proj_in->in(TypeFunc::Memory);
2716         }
2717       } else if (proj_in->is_MemBar()) {
2718         if (proj_in->in(TypeFunc::Memory)->is_MergeMem() &&
2719             proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->is_Proj() &&
2720             proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->is_ArrayCopy()) {
2721           // clone
2722           ArrayCopyNode* ac = proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->as_ArrayCopy();
2723           if (ac->may_modify(toop, igvn)) {
2724             break;
2725           }
2726         }
2727         result = proj_in->in(TypeFunc::Memory);
2728       }
2729     } else if (result->is_MergeMem()) {
2730       MergeMemNode *mmem = result->as_MergeMem();
2731       result = step_through_mergemem(mmem, alias_idx, toop);
2732       if (result == mmem->base_memory()) {
2733         // Didn't find instance memory, search through general slice recursively.
2734         result = mmem->memory_at(C->get_general_index(alias_idx));
2735         result = find_inst_mem(result, alias_idx, orig_phis);
2736         if (C->failing()) {
2737           return NULL;
2738         }
2739         mmem->set_memory_at(alias_idx, result);
2740       }
2741     } else if (result->is_Phi() &&
2742                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
2743       Node *un = result->as_Phi()->unique_input(igvn);
2744       if (un != NULL) {
2745         orig_phis.append_if_missing(result->as_Phi());
2746         result = un;
2747       } else {
2748         break;
2749       }
2750     } else if (result->is_ClearArray()) {
2751       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
2752         // Can not bypass initialization of the instance
2753         // we are looking for.
2754         break;
2755       }
2756       // Otherwise skip it (the call updated 'result' value).
2757     } else if (result->Opcode() == Op_SCMemProj) {
2758       Node* mem = result->in(0);
2759       Node* adr = NULL;
2760       if (mem->is_LoadStore()) {
2761         adr = mem->in(MemNode::Address);
2762       } else {
2763         assert(mem->Opcode() == Op_EncodeISOArray ||
2764                mem->Opcode() == Op_StrCompressedCopy, "sanity");
2765         adr = mem->in(3); // Memory edge corresponds to destination array
2766       }
2767       const Type *at = igvn->type(adr);
2768       if (at != Type::TOP) {
2769         assert(at->isa_ptr() != NULL, "pointer type required.");
2770         int idx = C->get_alias_index(at->is_ptr());
2771         if (idx == alias_idx) {
2772           // Assert in debug mode
2773           assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
2774           break; // In product mode return SCMemProj node
2775         }
2776       }
2777       result = mem->in(MemNode::Memory);
2778     } else if (result->Opcode() == Op_StrInflatedCopy) {
2779       Node* adr = result->in(3); // Memory edge corresponds to destination array
2780       const Type *at = igvn->type(adr);
2781       if (at != Type::TOP) {
2782         assert(at->isa_ptr() != NULL, "pointer type required.");
2783         int idx = C->get_alias_index(at->is_ptr());
2784         if (idx == alias_idx) {
2785           // Assert in debug mode
2786           assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
2787           break; // In product mode return SCMemProj node
2788         }
2789       }
2790       result = result->in(MemNode::Memory);
2791     }
2792   }
2793   if (result->is_Phi()) {
2794     PhiNode *mphi = result->as_Phi();
2795     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
2796     const TypePtr *t = mphi->adr_type();
2797     if (!is_instance) {
2798       // Push all non-instance Phis on the orig_phis worklist to update inputs
2799       // during Phase 4 if needed.
2800       orig_phis.append_if_missing(mphi);
2801     } else if (C->get_alias_index(t) != alias_idx) {
2802       // Create a new Phi with the specified alias index type.
2803       result = split_memory_phi(mphi, alias_idx, orig_phis);
2804     }
2805   }
2806   // the result is either MemNode, PhiNode, InitializeNode.
2807   return result;
2808 }
2809 
2810 //
2811 //  Convert the types of unescaped object to instance types where possible,
2812 //  propagate the new type information through the graph, and update memory
2813 //  edges and MergeMem inputs to reflect the new type.
2814 //
2815 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
2816 //  The processing is done in 4 phases:
2817 //
2818 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
2819 //            types for the CheckCastPP for allocations where possible.
2820 //            Propagate the new types through users as follows:
2821 //               casts and Phi:  push users on alloc_worklist
2822 //               AddP:  cast Base and Address inputs to the instance type
2823 //                      push any AddP users on alloc_worklist and push any memnode
2824 //                      users onto memnode_worklist.
2825 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
2826 //            search the Memory chain for a store with the appropriate type
2827 //            address type.  If a Phi is found, create a new version with
2828 //            the appropriate memory slices from each of the Phi inputs.
2829 //            For stores, process the users as follows:
2830 //               MemNode:  push on memnode_worklist
2831 //               MergeMem: push on mergemem_worklist
2832 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
2833 //            moving the first node encountered of each  instance type to the
2834 //            the input corresponding to its alias index.
2835 //            appropriate memory slice.
2836 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
2837 //
2838 // In the following example, the CheckCastPP nodes are the cast of allocation
2839 // results and the allocation of node 29 is unescaped and eligible to be an
2840 // instance type.
2841 //
2842 // We start with:
2843 //
2844 //     7 Parm #memory
2845 //    10  ConI  "12"
2846 //    19  CheckCastPP   "Foo"
2847 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2848 //    29  CheckCastPP   "Foo"
2849 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
2850 //
2851 //    40  StoreP  25   7  20   ... alias_index=4
2852 //    50  StoreP  35  40  30   ... alias_index=4
2853 //    60  StoreP  45  50  20   ... alias_index=4
2854 //    70  LoadP    _  60  30   ... alias_index=4
2855 //    80  Phi     75  50  60   Memory alias_index=4
2856 //    90  LoadP    _  80  30   ... alias_index=4
2857 //   100  LoadP    _  80  20   ... alias_index=4
2858 //
2859 //
2860 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
2861 // and creating a new alias index for node 30.  This gives:
2862 //
2863 //     7 Parm #memory
2864 //    10  ConI  "12"
2865 //    19  CheckCastPP   "Foo"
2866 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2867 //    29  CheckCastPP   "Foo"  iid=24
2868 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2869 //
2870 //    40  StoreP  25   7  20   ... alias_index=4
2871 //    50  StoreP  35  40  30   ... alias_index=6
2872 //    60  StoreP  45  50  20   ... alias_index=4
2873 //    70  LoadP    _  60  30   ... alias_index=6
2874 //    80  Phi     75  50  60   Memory alias_index=4
2875 //    90  LoadP    _  80  30   ... alias_index=6
2876 //   100  LoadP    _  80  20   ... alias_index=4
2877 //
2878 // In phase 2, new memory inputs are computed for the loads and stores,
2879 // And a new version of the phi is created.  In phase 4, the inputs to
2880 // node 80 are updated and then the memory nodes are updated with the
2881 // values computed in phase 2.  This results in:
2882 //
2883 //     7 Parm #memory
2884 //    10  ConI  "12"
2885 //    19  CheckCastPP   "Foo"
2886 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2887 //    29  CheckCastPP   "Foo"  iid=24
2888 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2889 //
2890 //    40  StoreP  25  7   20   ... alias_index=4
2891 //    50  StoreP  35  7   30   ... alias_index=6
2892 //    60  StoreP  45  40  20   ... alias_index=4
2893 //    70  LoadP    _  50  30   ... alias_index=6
2894 //    80  Phi     75  40  60   Memory alias_index=4
2895 //   120  Phi     75  50  50   Memory alias_index=6
2896 //    90  LoadP    _ 120  30   ... alias_index=6
2897 //   100  LoadP    _  80  20   ... alias_index=4
2898 //
2899 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist, GrowableArray<ArrayCopyNode*> &arraycopy_worklist) {
2900   GrowableArray<Node *>  memnode_worklist;
2901   GrowableArray<PhiNode *>  orig_phis;
2902   PhaseIterGVN  *igvn = _igvn;
2903   uint new_index_start = (uint) _compile->num_alias_types();
2904   Arena* arena = Thread::current()->resource_area();
2905   VectorSet visited(arena);
2906   ideal_nodes.clear(); // Reset for use with set_map/get_map.
2907   uint unique_old = _compile->unique();
2908 
2909   //  Phase 1:  Process possible allocations from alloc_worklist.
2910   //  Create instance types for the CheckCastPP for allocations where possible.
2911   //
2912   // (Note: don't forget to change the order of the second AddP node on
2913   //  the alloc_worklist if the order of the worklist processing is changed,
2914   //  see the comment in find_second_addp().)
2915   //
2916   while (alloc_worklist.length() != 0) {
2917     Node *n = alloc_worklist.pop();
2918     uint ni = n->_idx;
2919     if (n->is_Call()) {
2920       CallNode *alloc = n->as_Call();
2921       // copy escape information to call node
2922       PointsToNode* ptn = ptnode_adr(alloc->_idx);
2923       PointsToNode::EscapeState es = ptn->escape_state();
2924       // We have an allocation or call which returns a Java object,
2925       // see if it is unescaped.
2926       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
2927         continue;
2928       // Find CheckCastPP for the allocate or for the return value of a call
2929       n = alloc->result_cast();
2930       if (n == NULL) {            // No uses except Initialize node
2931         if (alloc->is_Allocate()) {
2932           // Set the scalar_replaceable flag for allocation
2933           // so it could be eliminated if it has no uses.
2934           alloc->as_Allocate()->_is_scalar_replaceable = true;
2935         }
2936         if (alloc->is_CallStaticJava()) {
2937           // Set the scalar_replaceable flag for boxing method
2938           // so it could be eliminated if it has no uses.
2939           alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2940         }
2941         continue;
2942       }
2943       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
2944         assert(!alloc->is_Allocate(), "allocation should have unique type");
2945         continue;
2946       }
2947 
2948       // The inline code for Object.clone() casts the allocation result to
2949       // java.lang.Object and then to the actual type of the allocated
2950       // object. Detect this case and use the second cast.
2951       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
2952       // the allocation result is cast to java.lang.Object and then
2953       // to the actual Array type.
2954       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
2955           && (alloc->is_AllocateArray() ||
2956               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
2957         Node *cast2 = NULL;
2958         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2959           Node *use = n->fast_out(i);
2960           if (use->is_CheckCastPP()) {
2961             cast2 = use;
2962             break;
2963           }
2964         }
2965         if (cast2 != NULL) {
2966           n = cast2;
2967         } else {
2968           // Non-scalar replaceable if the allocation type is unknown statically
2969           // (reflection allocation), the object can't be restored during
2970           // deoptimization without precise type.
2971           continue;
2972         }
2973       }
2974 
2975       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
2976       if (t == NULL)
2977         continue;  // not a TypeOopPtr
2978       if (!t->klass_is_exact())
2979         continue; // not an unique type
2980 
2981       if (alloc->is_Allocate()) {
2982         // Set the scalar_replaceable flag for allocation
2983         // so it could be eliminated.
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.
2989         alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2990       }
2991       set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
2992       // in order for an object to be scalar-replaceable, it must be:
2993       //   - a direct allocation (not a call returning an object)
2994       //   - non-escaping
2995       //   - eligible to be a unique type
2996       //   - not determined to be ineligible by escape analysis
2997       set_map(alloc, n);
2998       set_map(n, alloc);
2999       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
3000       igvn->hash_delete(n);
3001       igvn->set_type(n,  tinst);
3002       n->raise_bottom_type(tinst);
3003       igvn->hash_insert(n);
3004       record_for_optimizer(n);
3005       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr() || t->isa_valuetypeptr())) {
3006 
3007         // First, put on the worklist all Field edges from Connection Graph
3008         // which is more accurate than putting immediate users from Ideal Graph.
3009         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
3010           PointsToNode* tgt = e.get();
3011           if (tgt->is_Arraycopy()) {
3012             continue;
3013           }
3014           Node* use = tgt->ideal_node();
3015           assert(tgt->is_Field() && use->is_AddP(),
3016                  "only AddP nodes are Field edges in CG");
3017           if (use->outcnt() > 0) { // Don't process dead nodes
3018             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
3019             if (addp2 != NULL) {
3020               assert(alloc->is_AllocateArray(),"array allocation was expected");
3021               alloc_worklist.append_if_missing(addp2);
3022             }
3023             alloc_worklist.append_if_missing(use);
3024           }
3025         }
3026 
3027         // An allocation may have an Initialize which has raw stores. Scan
3028         // the users of the raw allocation result and push AddP users
3029         // on alloc_worklist.
3030         Node *raw_result = alloc->proj_out(TypeFunc::Parms);
3031         assert (raw_result != NULL, "must have an allocation result");
3032         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
3033           Node *use = raw_result->fast_out(i);
3034           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
3035             Node* addp2 = find_second_addp(use, raw_result);
3036             if (addp2 != NULL) {
3037               assert(alloc->is_AllocateArray(),"array allocation was expected");
3038               alloc_worklist.append_if_missing(addp2);
3039             }
3040             alloc_worklist.append_if_missing(use);
3041           } else if (use->is_MemBar()) {
3042             memnode_worklist.append_if_missing(use);
3043           }
3044         }
3045       }
3046     } else if (n->is_AddP()) {
3047       JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
3048       if (jobj == NULL || jobj == phantom_obj) {
3049 #ifdef ASSERT
3050         ptnode_adr(get_addp_base(n)->_idx)->dump();
3051         ptnode_adr(n->_idx)->dump();
3052         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3053 #endif
3054         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3055         return;
3056       }
3057       Node *base = get_map(jobj->idx());  // CheckCastPP node
3058       if (!split_AddP(n, base)) continue; // wrong type from dead path
3059     } else if (n->is_Phi() ||
3060                n->is_CheckCastPP() ||
3061                n->is_EncodeP() ||
3062                n->is_DecodeN() ||
3063                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
3064       if (visited.test_set(n->_idx)) {
3065         assert(n->is_Phi(), "loops only through Phi's");
3066         continue;  // already processed
3067       }
3068       JavaObjectNode* jobj = unique_java_object(n);
3069       if (jobj == NULL || jobj == phantom_obj) {
3070 #ifdef ASSERT
3071         ptnode_adr(n->_idx)->dump();
3072         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3073 #endif
3074         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3075         return;
3076       } else {
3077         Node *val = get_map(jobj->idx());   // CheckCastPP node
3078         TypeNode *tn = n->as_Type();
3079         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
3080         assert(tinst != NULL && tinst->is_known_instance() &&
3081                tinst->instance_id() == jobj->idx() , "instance type expected.");
3082 
3083         const Type *tn_type = igvn->type(tn);
3084         const TypeOopPtr *tn_t;
3085         if (tn_type->isa_narrowoop()) {
3086           tn_t = tn_type->make_ptr()->isa_oopptr();
3087         } else {
3088           tn_t = tn_type->isa_oopptr();
3089         }
3090         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
3091           if (tn_type->isa_narrowoop()) {
3092             tn_type = tinst->make_narrowoop();
3093           } else {
3094             tn_type = tinst;
3095           }
3096           igvn->hash_delete(tn);
3097           igvn->set_type(tn, tn_type);
3098           tn->set_type(tn_type);
3099           igvn->hash_insert(tn);
3100           record_for_optimizer(n);
3101         } else {
3102           assert(tn_type == TypePtr::NULL_PTR ||
3103                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
3104                  "unexpected type");
3105           continue; // Skip dead path with different type
3106         }
3107       }
3108     } else {
3109       debug_only(n->dump();)
3110       assert(false, "EA: unexpected node");
3111       continue;
3112     }
3113     // push allocation's users on appropriate worklist
3114     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3115       Node *use = n->fast_out(i);
3116       if(use->is_Mem() && use->in(MemNode::Address) == n) {
3117         // Load/store to instance's field
3118         memnode_worklist.append_if_missing(use);
3119       } else if (use->is_MemBar()) {
3120         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3121           memnode_worklist.append_if_missing(use);
3122         }
3123       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
3124         Node* addp2 = find_second_addp(use, n);
3125         if (addp2 != NULL) {
3126           alloc_worklist.append_if_missing(addp2);
3127         }
3128         alloc_worklist.append_if_missing(use);
3129       } else if (use->is_Phi() ||
3130                  use->is_CheckCastPP() ||
3131                  use->is_EncodeNarrowPtr() ||
3132                  use->is_DecodeNarrowPtr() ||
3133                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
3134         alloc_worklist.append_if_missing(use);
3135 #ifdef ASSERT
3136       } else if (use->is_Mem()) {
3137         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
3138       } else if (use->is_MergeMem()) {
3139         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3140       } else if (use->is_SafePoint()) {
3141         // Look for MergeMem nodes for calls which reference unique allocation
3142         // (through CheckCastPP nodes) even for debug info.
3143         Node* m = use->in(TypeFunc::Memory);
3144         if (m->is_MergeMem()) {
3145           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3146         }
3147       } else if (use->Opcode() == Op_EncodeISOArray) {
3148         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3149           // EncodeISOArray overwrites destination array
3150           memnode_worklist.append_if_missing(use);
3151         }
3152       } else {
3153         uint op = use->Opcode();
3154         if ((use->in(MemNode::Memory) == n) &&
3155             (op == Op_StrCompressedCopy || op == Op_StrInflatedCopy)) {
3156           // They overwrite memory edge corresponding to destination array,
3157           memnode_worklist.append_if_missing(use);
3158         } else if (!(op == Op_CmpP || op == Op_Conv2B ||
3159               op == Op_CastP2X || op == Op_StoreCM ||
3160               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp || op == Op_HasNegatives ||
3161               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
3162               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar ||
3163               op == Op_ValueType)) {
3164           n->dump();
3165           use->dump();
3166           assert(false, "EA: missing allocation reference path");
3167         }
3168 #endif
3169       }
3170     }
3171 
3172   }
3173 
3174   // Go over all ArrayCopy nodes and if one of the inputs has a unique
3175   // type, record it in the ArrayCopy node so we know what memory this
3176   // node uses/modified.
3177   for (int next = 0; next < arraycopy_worklist.length(); next++) {
3178     ArrayCopyNode* ac = arraycopy_worklist.at(next);
3179     Node* dest = ac->in(ArrayCopyNode::Dest);
3180     if (dest->is_AddP()) {
3181       dest = get_addp_base(dest);
3182     }
3183     JavaObjectNode* jobj = unique_java_object(dest);
3184     if (jobj != NULL) {
3185       Node *base = get_map(jobj->idx());
3186       if (base != NULL) {
3187         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3188         ac->_dest_type = base_t;
3189       }
3190     }
3191     Node* src = ac->in(ArrayCopyNode::Src);
3192     if (src->is_AddP()) {
3193       src = get_addp_base(src);
3194     }
3195     jobj = unique_java_object(src);
3196     if (jobj != NULL) {
3197       Node* base = get_map(jobj->idx());
3198       if (base != NULL) {
3199         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3200         ac->_src_type = base_t;
3201       }
3202     }
3203   }
3204 
3205   // New alias types were created in split_AddP().
3206   uint new_index_end = (uint) _compile->num_alias_types();
3207   assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
3208 
3209   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
3210   //            compute new values for Memory inputs  (the Memory inputs are not
3211   //            actually updated until phase 4.)
3212   if (memnode_worklist.length() == 0)
3213     return;  // nothing to do
3214   while (memnode_worklist.length() != 0) {
3215     Node *n = memnode_worklist.pop();
3216     if (visited.test_set(n->_idx))
3217       continue;
3218     if (n->is_Phi() || n->is_ClearArray()) {
3219       // we don't need to do anything, but the users must be pushed
3220     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
3221       // we don't need to do anything, but the users must be pushed
3222       n = n->as_MemBar()->proj_out(TypeFunc::Memory);
3223       if (n == NULL)
3224         continue;
3225     } else if (n->Opcode() == Op_StrCompressedCopy ||
3226                n->Opcode() == Op_EncodeISOArray) {
3227       // get the memory projection
3228       n = n->find_out_with(Op_SCMemProj);
3229       assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3230     } else {
3231       assert(n->is_Mem(), "memory node required.");
3232       Node *addr = n->in(MemNode::Address);
3233       const Type *addr_t = igvn->type(addr);
3234       if (addr_t == Type::TOP)
3235         continue;
3236       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
3237       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
3238       assert ((uint)alias_idx < new_index_end, "wrong alias index");
3239       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
3240       if (_compile->failing()) {
3241         return;
3242       }
3243       if (mem != n->in(MemNode::Memory)) {
3244         // We delay the memory edge update since we need old one in
3245         // MergeMem code below when instances memory slices are separated.
3246         set_map(n, mem);
3247       }
3248       if (n->is_Load()) {
3249         continue;  // don't push users
3250       } else if (n->is_LoadStore()) {
3251         // get the memory projection
3252         n = n->find_out_with(Op_SCMemProj);
3253         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3254       }
3255     }
3256     // push user on appropriate worklist
3257     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3258       Node *use = n->fast_out(i);
3259       if (use->is_Phi() || use->is_ClearArray()) {
3260         memnode_worklist.append_if_missing(use);
3261       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
3262         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
3263           continue;
3264         memnode_worklist.append_if_missing(use);
3265       } else if (use->is_MemBar()) {
3266         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3267           memnode_worklist.append_if_missing(use);
3268         }
3269 #ifdef ASSERT
3270       } else if(use->is_Mem()) {
3271         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
3272       } else if (use->is_MergeMem()) {
3273         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3274       } else if (use->Opcode() == Op_EncodeISOArray) {
3275         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3276           // EncodeISOArray overwrites destination array
3277           memnode_worklist.append_if_missing(use);
3278         }
3279       } else {
3280         uint op = use->Opcode();
3281         if ((use->in(MemNode::Memory) == n) &&
3282             (op == Op_StrCompressedCopy || op == Op_StrInflatedCopy)) {
3283           // They overwrite memory edge corresponding to destination array,
3284           memnode_worklist.append_if_missing(use);
3285         } else if (!(op == Op_StoreCM ||
3286               (op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&
3287                strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||
3288               op == Op_AryEq || op == Op_StrComp || op == Op_HasNegatives ||
3289               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
3290               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar)) {
3291           n->dump();
3292           use->dump();
3293           assert(false, "EA: missing memory path");
3294         }
3295 #endif
3296       }
3297     }
3298   }
3299 
3300   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
3301   //            Walk each memory slice moving the first node encountered of each
3302   //            instance type to the input corresponding to its alias index.
3303   uint length = _mergemem_worklist.length();
3304   for( uint next = 0; next < length; ++next ) {
3305     MergeMemNode* nmm = _mergemem_worklist.at(next);
3306     assert(!visited.test_set(nmm->_idx), "should not be visited before");
3307     // Note: we don't want to use MergeMemStream here because we only want to
3308     // scan inputs which exist at the start, not ones we add during processing.
3309     // Note 2: MergeMem may already contains instance memory slices added
3310     // during find_inst_mem() call when memory nodes were processed above.
3311     igvn->hash_delete(nmm);
3312     uint nslices = MIN2(nmm->req(), new_index_start);
3313     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
3314       Node* mem = nmm->in(i);
3315       Node* cur = NULL;
3316       if (mem == NULL || mem->is_top())
3317         continue;
3318       // First, update mergemem by moving memory nodes to corresponding slices
3319       // if their type became more precise since this mergemem was created.
3320       while (mem->is_Mem()) {
3321         const Type *at = igvn->type(mem->in(MemNode::Address));
3322         if (at != Type::TOP) {
3323           assert (at->isa_ptr() != NULL, "pointer type required.");
3324           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
3325           if (idx == i) {
3326             if (cur == NULL)
3327               cur = mem;
3328           } else {
3329             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
3330               nmm->set_memory_at(idx, mem);
3331             }
3332           }
3333         }
3334         mem = mem->in(MemNode::Memory);
3335       }
3336       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
3337       // Find any instance of the current type if we haven't encountered
3338       // already a memory slice of the instance along the memory chain.
3339       for (uint ni = new_index_start; ni < new_index_end; ni++) {
3340         if((uint)_compile->get_general_index(ni) == i) {
3341           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
3342           if (nmm->is_empty_memory(m)) {
3343             Node* result = find_inst_mem(mem, ni, orig_phis);
3344             if (_compile->failing()) {
3345               return;
3346             }
3347             nmm->set_memory_at(ni, result);
3348           }
3349         }
3350       }
3351     }
3352     // Find the rest of instances values
3353     for (uint ni = new_index_start; ni < new_index_end; ni++) {
3354       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
3355       Node* result = step_through_mergemem(nmm, ni, tinst);
3356       if (result == nmm->base_memory()) {
3357         // Didn't find instance memory, search through general slice recursively.
3358         result = nmm->memory_at(_compile->get_general_index(ni));
3359         result = find_inst_mem(result, ni, orig_phis);
3360         if (_compile->failing()) {
3361           return;
3362         }
3363         nmm->set_memory_at(ni, result);
3364       }
3365     }
3366     igvn->hash_insert(nmm);
3367     record_for_optimizer(nmm);
3368   }
3369 
3370   //  Phase 4:  Update the inputs of non-instance memory Phis and
3371   //            the Memory input of memnodes
3372   // First update the inputs of any non-instance Phi's from
3373   // which we split out an instance Phi.  Note we don't have
3374   // to recursively process Phi's encountered on the input memory
3375   // chains as is done in split_memory_phi() since they will
3376   // also be processed here.
3377   for (int j = 0; j < orig_phis.length(); j++) {
3378     PhiNode *phi = orig_phis.at(j);
3379     int alias_idx = _compile->get_alias_index(phi->adr_type());
3380     igvn->hash_delete(phi);
3381     for (uint i = 1; i < phi->req(); i++) {
3382       Node *mem = phi->in(i);
3383       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
3384       if (_compile->failing()) {
3385         return;
3386       }
3387       if (mem != new_mem) {
3388         phi->set_req(i, new_mem);
3389       }
3390     }
3391     igvn->hash_insert(phi);
3392     record_for_optimizer(phi);
3393   }
3394 
3395   // Update the memory inputs of MemNodes with the value we computed
3396   // in Phase 2 and move stores memory users to corresponding memory slices.
3397   // Disable memory split verification code until the fix for 6984348.
3398   // Currently it produces false negative results since it does not cover all cases.
3399 #if 0 // ifdef ASSERT
3400   visited.Reset();
3401   Node_Stack old_mems(arena, _compile->unique() >> 2);
3402 #endif
3403   for (uint i = 0; i < ideal_nodes.size(); i++) {
3404     Node*    n = ideal_nodes.at(i);
3405     Node* nmem = get_map(n->_idx);
3406     assert(nmem != NULL, "sanity");
3407     if (n->is_Mem()) {
3408 #if 0 // ifdef ASSERT
3409       Node* old_mem = n->in(MemNode::Memory);
3410       if (!visited.test_set(old_mem->_idx)) {
3411         old_mems.push(old_mem, old_mem->outcnt());
3412       }
3413 #endif
3414       assert(n->in(MemNode::Memory) != nmem, "sanity");
3415       if (!n->is_Load()) {
3416         // Move memory users of a store first.
3417         move_inst_mem(n, orig_phis);
3418       }
3419       // Now update memory input
3420       igvn->hash_delete(n);
3421       n->set_req(MemNode::Memory, nmem);
3422       igvn->hash_insert(n);
3423       record_for_optimizer(n);
3424     } else {
3425       assert(n->is_Allocate() || n->is_CheckCastPP() ||
3426              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
3427     }
3428   }
3429 #if 0 // ifdef ASSERT
3430   // Verify that memory was split correctly
3431   while (old_mems.is_nonempty()) {
3432     Node* old_mem = old_mems.node();
3433     uint  old_cnt = old_mems.index();
3434     old_mems.pop();
3435     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
3436   }
3437 #endif
3438 }
3439 
3440 #ifndef PRODUCT
3441 static const char *node_type_names[] = {
3442   "UnknownType",
3443   "JavaObject",
3444   "LocalVar",
3445   "Field",
3446   "Arraycopy"
3447 };
3448 
3449 static const char *esc_names[] = {
3450   "UnknownEscape",
3451   "NoEscape",
3452   "ArgEscape",
3453   "GlobalEscape"
3454 };
3455 
3456 void PointsToNode::dump(bool print_state) const {
3457   NodeType nt = node_type();
3458   tty->print("%s ", node_type_names[(int) nt]);
3459   if (print_state) {
3460     EscapeState es = escape_state();
3461     EscapeState fields_es = fields_escape_state();
3462     tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
3463     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
3464       tty->print("NSR ");
3465   }
3466   if (is_Field()) {
3467     FieldNode* f = (FieldNode*)this;
3468     if (f->is_oop())
3469       tty->print("oop ");
3470     if (f->offset() > 0)
3471       tty->print("+%d ", f->offset());
3472     tty->print("(");
3473     for (BaseIterator i(f); i.has_next(); i.next()) {
3474       PointsToNode* b = i.get();
3475       tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
3476     }
3477     tty->print(" )");
3478   }
3479   tty->print("[");
3480   for (EdgeIterator i(this); i.has_next(); i.next()) {
3481     PointsToNode* e = i.get();
3482     tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
3483   }
3484   tty->print(" [");
3485   for (UseIterator i(this); i.has_next(); i.next()) {
3486     PointsToNode* u = i.get();
3487     bool is_base = false;
3488     if (PointsToNode::is_base_use(u)) {
3489       is_base = true;
3490       u = PointsToNode::get_use_node(u)->as_Field();
3491     }
3492     tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
3493   }
3494   tty->print(" ]]  ");
3495   if (_node == NULL)
3496     tty->print_cr("<null>");
3497   else
3498     _node->dump();
3499 }
3500 
3501 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
3502   bool first = true;
3503   int ptnodes_length = ptnodes_worklist.length();
3504   for (int i = 0; i < ptnodes_length; i++) {
3505     PointsToNode *ptn = ptnodes_worklist.at(i);
3506     if (ptn == NULL || !ptn->is_JavaObject())
3507       continue;
3508     PointsToNode::EscapeState es = ptn->escape_state();
3509     if ((es != PointsToNode::NoEscape) && !Verbose) {
3510       continue;
3511     }
3512     Node* n = ptn->ideal_node();
3513     if (n->is_Allocate() || (n->is_CallStaticJava() &&
3514                              n->as_CallStaticJava()->is_boxing_method())) {
3515       if (first) {
3516         tty->cr();
3517         tty->print("======== Connection graph for ");
3518         _compile->method()->print_short_name();
3519         tty->cr();
3520         first = false;
3521       }
3522       ptn->dump();
3523       // Print all locals and fields which reference this allocation
3524       for (UseIterator j(ptn); j.has_next(); j.next()) {
3525         PointsToNode* use = j.get();
3526         if (use->is_LocalVar()) {
3527           use->dump(Verbose);
3528         } else if (Verbose) {
3529           use->dump();
3530         }
3531       }
3532       tty->cr();
3533     }
3534   }
3535 }
3536 #endif