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();
 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();
 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();
1061         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1062           const Type* at = d->field_at(i);
1063           int k = i - TypeFunc::Parms;
1064           Node* arg = call->in(i);
1065           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
1066           if (at->isa_ptr() != NULL &&
1067               call_analyzer->is_arg_returned(k)) {
1068             // The call returns arguments.
1069             if (call_ptn != NULL) { // Is call's result used?
1070               assert(call_ptn->is_LocalVar(), "node should be registered");
1071               assert(arg_ptn != NULL, "node should be registered");
1072               add_edge(call_ptn, arg_ptn);
1073             }
1074           }
1075           if (at->isa_oopptr() != NULL &&
1076               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
1077             if (!call_analyzer->is_arg_stack(k)) {
1078               // The argument global escapes
1079               set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1080             } else {
1081               set_escape_state(arg_ptn, PointsToNode::ArgEscape);
1082               if (!call_analyzer->is_arg_local(k)) {
1083                 // The argument itself doesn't escape, but any fields might
1084                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1085               }
1086             }
1087           }
1088         }
1089         if (call_ptn != NULL && call_ptn->is_LocalVar()) {
1090           // The call returns arguments.
1091           assert(call_ptn->edge_count() > 0, "sanity");
1092           if (!call_analyzer->is_return_local()) {
1093             // Returns also unknown object.
1094             add_edge(call_ptn, phantom_obj);
1095           }
1096         }
1097         break;
1098       }
1099     }
1100     default: {
1101       // Fall-through here if not a Java method or no analyzer information
1102       // or some other type of call, assume the worst case: all arguments
1103       // globally escape.
1104       const TypeTuple* d = call->tf()->domain();
1105       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1106         const Type* at = d->field_at(i);
1107         if (at->isa_oopptr() != NULL) {
1108           Node* arg = call->in(i);
1109           if (arg->is_AddP()) {
1110             arg = get_addp_base(arg);
1111           }
1112           assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
1113           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
1114         }
1115       }
1116     }
1117   }
1118 }
1119 
1120 
1121 // Finish Graph construction.
1122 bool ConnectionGraph::complete_connection_graph(
1123                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1124                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1125                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1126                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
1127   // Normally only 1-3 passes needed to build Connection Graph depending
1128   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
1129   // Set limit to 20 to catch situation when something did go wrong and
1130   // bailout Escape Analysis.
1131   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
1132 #define CG_BUILD_ITER_LIMIT 20
1133 
1134   // Propagate GlobalEscape and ArgEscape escape states and check that
1135   // we still have non-escaping objects. The method pushs on _worklist
1136   // Field nodes which reference phantom_object.
1137   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1138     return false; // Nothing to do.
1139   }
1140   // Now propagate references to all JavaObject nodes.
1141   int java_objects_length = java_objects_worklist.length();
1142   elapsedTimer time;
1143   bool timeout = false;
1144   int new_edges = 1;
1145   int iterations = 0;
1146   do {
1147     while ((new_edges > 0) &&
1148            (iterations++ < CG_BUILD_ITER_LIMIT)) {
1149       double start_time = time.seconds();
1150       time.start();
1151       new_edges = 0;
1152       // Propagate references to phantom_object for nodes pushed on _worklist
1153       // by find_non_escaped_objects() and find_field_value().
1154       new_edges += add_java_object_edges(phantom_obj, false);
1155       for (int next = 0; next < java_objects_length; ++next) {
1156         JavaObjectNode* ptn = java_objects_worklist.at(next);
1157         new_edges += add_java_object_edges(ptn, true);
1158 
1159 #define SAMPLE_SIZE 4
1160         if ((next % SAMPLE_SIZE) == 0) {
1161           // Each 4 iterations calculate how much time it will take
1162           // to complete graph construction.
1163           time.stop();
1164           // Poll for requests from shutdown mechanism to quiesce compiler
1165           // because Connection graph construction may take long time.
1166           CompileBroker::maybe_block();
1167           double stop_time = time.seconds();
1168           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
1169           double time_until_end = time_per_iter * (double)(java_objects_length - next);
1170           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
1171             timeout = true;
1172             break; // Timeout
1173           }
1174           start_time = stop_time;
1175           time.start();
1176         }
1177 #undef SAMPLE_SIZE
1178 
1179       }
1180       if (timeout) break;
1181       if (new_edges > 0) {
1182         // Update escape states on each iteration if graph was updated.
1183         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1184           return false; // Nothing to do.
1185         }
1186       }
1187       time.stop();
1188       if (time.seconds() >= EscapeAnalysisTimeout) {
1189         timeout = true;
1190         break;
1191       }
1192     }
1193     if ((iterations < CG_BUILD_ITER_LIMIT) && !timeout) {
1194       time.start();
1195       // Find fields which have unknown value.
1196       int fields_length = oop_fields_worklist.length();
1197       for (int next = 0; next < fields_length; next++) {
1198         FieldNode* field = oop_fields_worklist.at(next);
1199         if (field->edge_count() == 0) {
1200           new_edges += find_field_value(field);
1201           // This code may added new edges to phantom_object.
1202           // Need an other cycle to propagate references to phantom_object.
1203         }
1204       }
1205       time.stop();
1206       if (time.seconds() >= EscapeAnalysisTimeout) {
1207         timeout = true;
1208         break;
1209       }
1210     } else {
1211       new_edges = 0; // Bailout
1212     }
1213   } while (new_edges > 0);
1214 
1215   // Bailout if passed limits.
1216   if ((iterations >= CG_BUILD_ITER_LIMIT) || timeout) {
1217     Compile* C = _compile;
1218     if (C->log() != NULL) {
1219       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
1220       C->log()->text("%s", timeout ? "time" : "iterations");
1221       C->log()->end_elem(" limit'");
1222     }
1223     assert(ExitEscapeAnalysisOnTimeout, "infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
1224            time.seconds(), iterations, nodes_size(), ptnodes_worklist.length());
1225     // Possible infinite build_connection_graph loop,
1226     // bailout (no changes to ideal graph were made).
1227     return false;
1228   }
1229 #ifdef ASSERT
1230   if (Verbose && PrintEscapeAnalysis) {
1231     tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
1232                   iterations, nodes_size(), ptnodes_worklist.length());
1233   }
1234 #endif
1235 
1236 #undef CG_BUILD_ITER_LIMIT
1237 
1238   // Find fields initialized by NULL for non-escaping Allocations.
1239   int non_escaped_length = non_escaped_worklist.length();
1240   for (int next = 0; next < non_escaped_length; next++) {
1241     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1242     PointsToNode::EscapeState es = ptn->escape_state();
1243     assert(es <= PointsToNode::ArgEscape, "sanity");
1244     if (es == PointsToNode::NoEscape) {
1245       if (find_init_values(ptn, null_obj, _igvn) > 0) {
1246         // Adding references to NULL object does not change escape states
1247         // since it does not escape. Also no fields are added to NULL object.
1248         add_java_object_edges(null_obj, false);
1249       }
1250     }
1251     Node* n = ptn->ideal_node();
1252     if (n->is_Allocate()) {
1253       // The object allocated by this Allocate node will never be
1254       // seen by an other thread. Mark it so that when it is
1255       // expanded no MemBarStoreStore is added.
1256       InitializeNode* ini = n->as_Allocate()->initialization();
1257       if (ini != NULL)
1258         ini->set_does_not_escape();
1259     }
1260   }
1261   return true; // Finished graph construction.
1262 }
1263 
1264 // Propagate GlobalEscape and ArgEscape escape states to all nodes
1265 // and check that we still have non-escaping java objects.
1266 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
1267                                                GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
1268   GrowableArray<PointsToNode*> escape_worklist;
1269   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
1270   int ptnodes_length = ptnodes_worklist.length();
1271   for (int next = 0; next < ptnodes_length; ++next) {
1272     PointsToNode* ptn = ptnodes_worklist.at(next);
1273     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
1274         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
1275       escape_worklist.push(ptn);
1276     }
1277   }
1278   // Set escape states to referenced nodes (edges list).
1279   while (escape_worklist.length() > 0) {
1280     PointsToNode* ptn = escape_worklist.pop();
1281     PointsToNode::EscapeState es  = ptn->escape_state();
1282     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
1283     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
1284         es >= PointsToNode::ArgEscape) {
1285       // GlobalEscape or ArgEscape state of field means it has unknown value.
1286       if (add_edge(ptn, phantom_obj)) {
1287         // New edge was added
1288         add_field_uses_to_worklist(ptn->as_Field());
1289       }
1290     }
1291     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1292       PointsToNode* e = i.get();
1293       if (e->is_Arraycopy()) {
1294         assert(ptn->arraycopy_dst(), "sanity");
1295         // Propagate only fields escape state through arraycopy edge.
1296         if (e->fields_escape_state() < field_es) {
1297           set_fields_escape_state(e, field_es);
1298           escape_worklist.push(e);
1299         }
1300       } else if (es >= field_es) {
1301         // fields_escape_state is also set to 'es' if it is less than 'es'.
1302         if (e->escape_state() < es) {
1303           set_escape_state(e, es);
1304           escape_worklist.push(e);
1305         }
1306       } else {
1307         // Propagate field escape state.
1308         bool es_changed = false;
1309         if (e->fields_escape_state() < field_es) {
1310           set_fields_escape_state(e, field_es);
1311           es_changed = true;
1312         }
1313         if ((e->escape_state() < field_es) &&
1314             e->is_Field() && ptn->is_JavaObject() &&
1315             e->as_Field()->is_oop()) {
1316           // Change escape state of referenced fields.
1317           set_escape_state(e, field_es);
1318           es_changed = true;
1319         } else if (e->escape_state() < es) {
1320           set_escape_state(e, es);
1321           es_changed = true;
1322         }
1323         if (es_changed) {
1324           escape_worklist.push(e);
1325         }
1326       }
1327     }
1328   }
1329   // Remove escaped objects from non_escaped list.
1330   for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
1331     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1332     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
1333       non_escaped_worklist.delete_at(next);
1334     }
1335     if (ptn->escape_state() == PointsToNode::NoEscape) {
1336       // Find fields in non-escaped allocations which have unknown value.
1337       find_init_values(ptn, phantom_obj, NULL);
1338     }
1339   }
1340   return (non_escaped_worklist.length() > 0);
1341 }
1342 
1343 // Add all references to JavaObject node by walking over all uses.
1344 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
1345   int new_edges = 0;
1346   if (populate_worklist) {
1347     // Populate _worklist by uses of jobj's uses.
1348     for (UseIterator i(jobj); i.has_next(); i.next()) {
1349       PointsToNode* use = i.get();
1350       if (use->is_Arraycopy())
1351         continue;
1352       add_uses_to_worklist(use);
1353       if (use->is_Field() && use->as_Field()->is_oop()) {
1354         // Put on worklist all field's uses (loads) and
1355         // related field nodes (same base and offset).
1356         add_field_uses_to_worklist(use->as_Field());
1357       }
1358     }
1359   }
1360   for (int l = 0; l < _worklist.length(); l++) {
1361     PointsToNode* use = _worklist.at(l);
1362     if (PointsToNode::is_base_use(use)) {
1363       // Add reference from jobj to field and from field to jobj (field's base).
1364       use = PointsToNode::get_use_node(use)->as_Field();
1365       if (add_base(use->as_Field(), jobj)) {
1366         new_edges++;
1367       }
1368       continue;
1369     }
1370     assert(!use->is_JavaObject(), "sanity");
1371     if (use->is_Arraycopy()) {
1372       if (jobj == null_obj) // NULL object does not have field edges
1373         continue;
1374       // Added edge from Arraycopy node to arraycopy's source java object
1375       if (add_edge(use, jobj)) {
1376         jobj->set_arraycopy_src();
1377         new_edges++;
1378       }
1379       // and stop here.
1380       continue;
1381     }
1382     if (!add_edge(use, jobj))
1383       continue; // No new edge added, there was such edge already.
1384     new_edges++;
1385     if (use->is_LocalVar()) {
1386       add_uses_to_worklist(use);
1387       if (use->arraycopy_dst()) {
1388         for (EdgeIterator i(use); i.has_next(); i.next()) {
1389           PointsToNode* e = i.get();
1390           if (e->is_Arraycopy()) {
1391             if (jobj == null_obj) // NULL object does not have field edges
1392               continue;
1393             // Add edge from arraycopy's destination java object to Arraycopy node.
1394             if (add_edge(jobj, e)) {
1395               new_edges++;
1396               jobj->set_arraycopy_dst();
1397             }
1398           }
1399         }
1400       }
1401     } else {
1402       // Added new edge to stored in field values.
1403       // Put on worklist all field's uses (loads) and
1404       // related field nodes (same base and offset).
1405       add_field_uses_to_worklist(use->as_Field());
1406     }
1407   }
1408   _worklist.clear();
1409   _in_worklist.Reset();
1410   return new_edges;
1411 }
1412 
1413 // Put on worklist all related field nodes.
1414 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
1415   assert(field->is_oop(), "sanity");
1416   int offset = field->offset();
1417   add_uses_to_worklist(field);
1418   // Loop over all bases of this field and push on worklist Field nodes
1419   // with the same offset and base (since they may reference the same field).
1420   for (BaseIterator i(field); i.has_next(); i.next()) {
1421     PointsToNode* base = i.get();
1422     add_fields_to_worklist(field, base);
1423     // Check if the base was source object of arraycopy and go over arraycopy's
1424     // destination objects since values stored to a field of source object are
1425     // accessable by uses (loads) of fields of destination objects.
1426     if (base->arraycopy_src()) {
1427       for (UseIterator j(base); j.has_next(); j.next()) {
1428         PointsToNode* arycp = j.get();
1429         if (arycp->is_Arraycopy()) {
1430           for (UseIterator k(arycp); k.has_next(); k.next()) {
1431             PointsToNode* abase = k.get();
1432             if (abase->arraycopy_dst() && abase != base) {
1433               // Look for the same arraycopy reference.
1434               add_fields_to_worklist(field, abase);
1435             }
1436           }
1437         }
1438       }
1439     }
1440   }
1441 }
1442 
1443 // Put on worklist all related field nodes.
1444 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
1445   int offset = field->offset();
1446   if (base->is_LocalVar()) {
1447     for (UseIterator j(base); j.has_next(); j.next()) {
1448       PointsToNode* f = j.get();
1449       if (PointsToNode::is_base_use(f)) { // Field
1450         f = PointsToNode::get_use_node(f);
1451         if (f == field || !f->as_Field()->is_oop())
1452           continue;
1453         int offs = f->as_Field()->offset();
1454         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1455           add_to_worklist(f);
1456         }
1457       }
1458     }
1459   } else {
1460     assert(base->is_JavaObject(), "sanity");
1461     if (// Skip phantom_object since it is only used to indicate that
1462         // this field's content globally escapes.
1463         (base != phantom_obj) &&
1464         // NULL object node does not have fields.
1465         (base != null_obj)) {
1466       for (EdgeIterator i(base); i.has_next(); i.next()) {
1467         PointsToNode* f = i.get();
1468         // Skip arraycopy edge since store to destination object field
1469         // does not update value in source object field.
1470         if (f->is_Arraycopy()) {
1471           assert(base->arraycopy_dst(), "sanity");
1472           continue;
1473         }
1474         if (f == field || !f->as_Field()->is_oop())
1475           continue;
1476         int offs = f->as_Field()->offset();
1477         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1478           add_to_worklist(f);
1479         }
1480       }
1481     }
1482   }
1483 }
1484 
1485 // Find fields which have unknown value.
1486 int ConnectionGraph::find_field_value(FieldNode* field) {
1487   // Escaped fields should have init value already.
1488   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
1489   int new_edges = 0;
1490   for (BaseIterator i(field); i.has_next(); i.next()) {
1491     PointsToNode* base = i.get();
1492     if (base->is_JavaObject()) {
1493       // Skip Allocate's fields which will be processed later.
1494       if (base->ideal_node()->is_Allocate())
1495         return 0;
1496       assert(base == null_obj, "only NULL ptr base expected here");
1497     }
1498   }
1499   if (add_edge(field, phantom_obj)) {
1500     // New edge was added
1501     new_edges++;
1502     add_field_uses_to_worklist(field);
1503   }
1504   return new_edges;
1505 }
1506 
1507 // Find fields initializing values for allocations.
1508 int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
1509   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
1510   int new_edges = 0;
1511   Node* alloc = pta->ideal_node();
1512   if (init_val == phantom_obj) {
1513     // Do nothing for Allocate nodes since its fields values are
1514     // "known" unless they are initialized by arraycopy/clone.
1515     if (alloc->is_Allocate() && !pta->arraycopy_dst())
1516       return 0;
1517     assert(pta->arraycopy_dst() || alloc->as_CallStaticJava(), "sanity");
1518 #ifdef ASSERT
1519     if (!pta->arraycopy_dst() && alloc->as_CallStaticJava()->method() == NULL) {
1520       const char* name = alloc->as_CallStaticJava()->_name;
1521       assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
1522     }
1523 #endif
1524     // Non-escaped allocation returned from Java or runtime call have
1525     // unknown values in fields.
1526     for (EdgeIterator i(pta); i.has_next(); i.next()) {
1527       PointsToNode* field = i.get();
1528       if (field->is_Field() && field->as_Field()->is_oop()) {
1529         if (add_edge(field, phantom_obj)) {
1530           // New edge was added
1531           new_edges++;
1532           add_field_uses_to_worklist(field->as_Field());
1533         }
1534       }
1535     }
1536     return new_edges;
1537   }
1538   assert(init_val == null_obj, "sanity");
1539   // Do nothing for Call nodes since its fields values are unknown.
1540   if (!alloc->is_Allocate())
1541     return 0;
1542 
1543   InitializeNode* ini = alloc->as_Allocate()->initialization();
1544   bool visited_bottom_offset = false;
1545   GrowableArray<int> offsets_worklist;
1546 
1547   // Check if an oop field's initializing value is recorded and add
1548   // a corresponding NULL if field's value if it is not recorded.
1549   // Connection Graph does not record a default initialization by NULL
1550   // captured by Initialize node.
1551   //
1552   for (EdgeIterator i(pta); i.has_next(); i.next()) {
1553     PointsToNode* field = i.get(); // Field (AddP)
1554     if (!field->is_Field() || !field->as_Field()->is_oop())
1555       continue; // Not oop field
1556     int offset = field->as_Field()->offset();
1557     if (offset == Type::OffsetBot) {
1558       if (!visited_bottom_offset) {
1559         // OffsetBot is used to reference array's element,
1560         // always add reference to NULL to all Field nodes since we don't
1561         // known which element is referenced.
1562         if (add_edge(field, null_obj)) {
1563           // New edge was added
1564           new_edges++;
1565           add_field_uses_to_worklist(field->as_Field());
1566           visited_bottom_offset = true;
1567         }
1568       }
1569     } else {
1570       // Check only oop fields.
1571       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
1572       if (adr_type->isa_rawptr()) {
1573 #ifdef ASSERT
1574         // Raw pointers are used for initializing stores so skip it
1575         // since it should be recorded already
1576         Node* base = get_addp_base(field->ideal_node());
1577         assert(adr_type->isa_rawptr() && base->is_Proj() &&
1578                (base->in(0) == alloc),"unexpected pointer type");
1579 #endif
1580         continue;
1581       }
1582       if (!offsets_worklist.contains(offset)) {
1583         offsets_worklist.append(offset);
1584         Node* value = NULL;
1585         if (ini != NULL) {
1586           // StoreP::memory_type() == T_ADDRESS
1587           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
1588           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
1589           // Make sure initializing store has the same type as this AddP.
1590           // This AddP may reference non existing field because it is on a
1591           // dead branch of bimorphic call which is not eliminated yet.
1592           if (store != NULL && store->is_Store() &&
1593               store->as_Store()->memory_type() == ft) {
1594             value = store->in(MemNode::ValueIn);
1595 #ifdef ASSERT
1596             if (VerifyConnectionGraph) {
1597               // Verify that AddP already points to all objects the value points to.
1598               PointsToNode* val = ptnode_adr(value->_idx);
1599               assert((val != NULL), "should be processed already");
1600               PointsToNode* missed_obj = NULL;
1601               if (val->is_JavaObject()) {
1602                 if (!field->points_to(val->as_JavaObject())) {
1603                   missed_obj = val;
1604                 }
1605               } else {
1606                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
1607                   tty->print_cr("----------init store has invalid value -----");
1608                   store->dump();
1609                   val->dump();
1610                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
1611                 }
1612                 for (EdgeIterator j(val); j.has_next(); j.next()) {
1613                   PointsToNode* obj = j.get();
1614                   if (obj->is_JavaObject()) {
1615                     if (!field->points_to(obj->as_JavaObject())) {
1616                       missed_obj = obj;
1617                       break;
1618                     }
1619                   }
1620                 }
1621               }
1622               if (missed_obj != NULL) {
1623                 tty->print_cr("----------field---------------------------------");
1624                 field->dump();
1625                 tty->print_cr("----------missed referernce to object-----------");
1626                 missed_obj->dump();
1627                 tty->print_cr("----------object referernced by init store -----");
1628                 store->dump();
1629                 val->dump();
1630                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
1631               }
1632             }
1633 #endif
1634           } else {
1635             // There could be initializing stores which follow allocation.
1636             // For example, a volatile field store is not collected
1637             // by Initialize node.
1638             //
1639             // Need to check for dependent loads to separate such stores from
1640             // stores which follow loads. For now, add initial value NULL so
1641             // that compare pointers optimization works correctly.
1642           }
1643         }
1644         if (value == NULL) {
1645           // A field's initializing value was not recorded. Add NULL.
1646           if (add_edge(field, null_obj)) {
1647             // New edge was added
1648             new_edges++;
1649             add_field_uses_to_worklist(field->as_Field());
1650           }
1651         }
1652       }
1653     }
1654   }
1655   return new_edges;
1656 }
1657 
1658 // Adjust scalar_replaceable state after Connection Graph is built.
1659 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
1660   // Search for non-escaping objects which are not scalar replaceable
1661   // and mark them to propagate the state to referenced objects.
1662 
1663   // 1. An object is not scalar replaceable if the field into which it is
1664   // stored has unknown offset (stored into unknown element of an array).
1665   //
1666   for (UseIterator i(jobj); i.has_next(); i.next()) {
1667     PointsToNode* use = i.get();
1668     if (use->is_Arraycopy()) {
1669       continue;
1670     }
1671     if (use->is_Field()) {
1672       FieldNode* field = use->as_Field();
1673       assert(field->is_oop() && field->scalar_replaceable(), "sanity");
1674       if (field->offset() == Type::OffsetBot) {
1675         jobj->set_scalar_replaceable(false);
1676         return;
1677       }
1678       // 2. An object is not scalar replaceable if the field into which it is
1679       // stored has multiple bases one of which is null.
1680       if (field->base_count() > 1) {
1681         for (BaseIterator i(field); i.has_next(); i.next()) {
1682           PointsToNode* base = i.get();
1683           if (base == null_obj) {
1684             jobj->set_scalar_replaceable(false);
1685             return;
1686           }
1687         }
1688       }
1689     }
1690     assert(use->is_Field() || use->is_LocalVar(), "sanity");
1691     // 3. An object is not scalar replaceable if it is merged with other objects.
1692     for (EdgeIterator j(use); j.has_next(); j.next()) {
1693       PointsToNode* ptn = j.get();
1694       if (ptn->is_JavaObject() && ptn != jobj) {
1695         // Mark all objects.
1696         jobj->set_scalar_replaceable(false);
1697          ptn->set_scalar_replaceable(false);
1698       }
1699     }
1700     if (!jobj->scalar_replaceable()) {
1701       return;
1702     }
1703   }
1704 
1705   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
1706     if (j.get()->is_Arraycopy()) {
1707       continue;
1708     }
1709 
1710     // Non-escaping object node should point only to field nodes.
1711     FieldNode* field = j.get()->as_Field();
1712     int offset = field->as_Field()->offset();
1713 
1714     // 4. An object is not scalar replaceable if it has a field with unknown
1715     // offset (array's element is accessed in loop).
1716     if (offset == Type::OffsetBot) {
1717       jobj->set_scalar_replaceable(false);
1718       return;
1719     }
1720     // 5. Currently an object is not scalar replaceable if a LoadStore node
1721     // access its field since the field value is unknown after it.
1722     //
1723     Node* n = field->ideal_node();
1724     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1725       if (n->fast_out(i)->is_LoadStore()) {
1726         jobj->set_scalar_replaceable(false);
1727         return;
1728       }
1729     }
1730 
1731     // 6. Or the address may point to more then one object. This may produce
1732     // the false positive result (set not scalar replaceable)
1733     // since the flow-insensitive escape analysis can't separate
1734     // the case when stores overwrite the field's value from the case
1735     // when stores happened on different control branches.
1736     //
1737     // Note: it will disable scalar replacement in some cases:
1738     //
1739     //    Point p[] = new Point[1];
1740     //    p[0] = new Point(); // Will be not scalar replaced
1741     //
1742     // but it will save us from incorrect optimizations in next cases:
1743     //
1744     //    Point p[] = new Point[1];
1745     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
1746     //
1747     if (field->base_count() > 1) {
1748       for (BaseIterator i(field); i.has_next(); i.next()) {
1749         PointsToNode* base = i.get();
1750         // Don't take into account LocalVar nodes which
1751         // may point to only one object which should be also
1752         // this field's base by now.
1753         if (base->is_JavaObject() && base != jobj) {
1754           // Mark all bases.
1755           jobj->set_scalar_replaceable(false);
1756           base->set_scalar_replaceable(false);
1757         }
1758       }
1759     }
1760   }
1761 }
1762 
1763 #ifdef ASSERT
1764 void ConnectionGraph::verify_connection_graph(
1765                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1766                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1767                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1768                          GrowableArray<Node*>& addp_worklist) {
1769   // Verify that graph is complete - no new edges could be added.
1770   int java_objects_length = java_objects_worklist.length();
1771   int non_escaped_length  = non_escaped_worklist.length();
1772   int new_edges = 0;
1773   for (int next = 0; next < java_objects_length; ++next) {
1774     JavaObjectNode* ptn = java_objects_worklist.at(next);
1775     new_edges += add_java_object_edges(ptn, true);
1776   }
1777   assert(new_edges == 0, "graph was not complete");
1778   // Verify that escape state is final.
1779   int length = non_escaped_worklist.length();
1780   find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
1781   assert((non_escaped_length == non_escaped_worklist.length()) &&
1782          (non_escaped_length == length) &&
1783          (_worklist.length() == 0), "escape state was not final");
1784 
1785   // Verify fields information.
1786   int addp_length = addp_worklist.length();
1787   for (int next = 0; next < addp_length; ++next ) {
1788     Node* n = addp_worklist.at(next);
1789     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
1790     if (field->is_oop()) {
1791       // Verify that field has all bases
1792       Node* base = get_addp_base(n);
1793       PointsToNode* ptn = ptnode_adr(base->_idx);
1794       if (ptn->is_JavaObject()) {
1795         assert(field->has_base(ptn->as_JavaObject()), "sanity");
1796       } else {
1797         assert(ptn->is_LocalVar(), "sanity");
1798         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1799           PointsToNode* e = i.get();
1800           if (e->is_JavaObject()) {
1801             assert(field->has_base(e->as_JavaObject()), "sanity");
1802           }
1803         }
1804       }
1805       // Verify that all fields have initializing values.
1806       if (field->edge_count() == 0) {
1807         tty->print_cr("----------field does not have references----------");
1808         field->dump();
1809         for (BaseIterator i(field); i.has_next(); i.next()) {
1810           PointsToNode* base = i.get();
1811           tty->print_cr("----------field has next base---------------------");
1812           base->dump();
1813           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
1814             tty->print_cr("----------base has fields-------------------------");
1815             for (EdgeIterator j(base); j.has_next(); j.next()) {
1816               j.get()->dump();
1817             }
1818             tty->print_cr("----------base has references---------------------");
1819             for (UseIterator j(base); j.has_next(); j.next()) {
1820               j.get()->dump();
1821             }
1822           }
1823         }
1824         for (UseIterator i(field); i.has_next(); i.next()) {
1825           i.get()->dump();
1826         }
1827         assert(field->edge_count() > 0, "sanity");
1828       }
1829     }
1830   }
1831 }
1832 #endif
1833 
1834 // Optimize ideal graph.
1835 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
1836                                            GrowableArray<Node*>& storestore_worklist) {
1837   Compile* C = _compile;
1838   PhaseIterGVN* igvn = _igvn;
1839   if (EliminateLocks) {
1840     // Mark locks before changing ideal graph.
1841     int cnt = C->macro_count();
1842     for( int i=0; i < cnt; i++ ) {
1843       Node *n = C->macro_node(i);
1844       if (n->is_AbstractLock()) { // Lock and Unlock nodes
1845         AbstractLockNode* alock = n->as_AbstractLock();
1846         if (!alock->is_non_esc_obj()) {
1847           if (not_global_escape(alock->obj_node())) {
1848             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
1849             // The lock could be marked eliminated by lock coarsening
1850             // code during first IGVN before EA. Replace coarsened flag
1851             // to eliminate all associated locks/unlocks.
1852 #ifdef ASSERT
1853             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
1854 #endif
1855             alock->set_non_esc_obj();
1856           }
1857         }
1858       }
1859     }
1860   }
1861 
1862   if (OptimizePtrCompare) {
1863     // Add ConI(#CC_GT) and ConI(#CC_EQ).
1864     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);
1865     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
1866     // Optimize objects compare.
1867     while (ptr_cmp_worklist.length() != 0) {
1868       Node *n = ptr_cmp_worklist.pop();
1869       Node *res = optimize_ptr_compare(n);
1870       if (res != NULL) {
1871 #ifndef PRODUCT
1872         if (PrintOptimizePtrCompare) {
1873           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"));
1874           if (Verbose) {
1875             n->dump(1);
1876           }
1877         }
1878 #endif
1879         igvn->replace_node(n, res);
1880       }
1881     }
1882     // cleanup
1883     if (_pcmp_neq->outcnt() == 0)
1884       igvn->hash_delete(_pcmp_neq);
1885     if (_pcmp_eq->outcnt()  == 0)
1886       igvn->hash_delete(_pcmp_eq);
1887   }
1888 
1889   // For MemBarStoreStore nodes added in library_call.cpp, check
1890   // escape status of associated AllocateNode and optimize out
1891   // MemBarStoreStore node if the allocated object never escapes.
1892   while (storestore_worklist.length() != 0) {
1893     Node *n = storestore_worklist.pop();
1894     MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
1895     Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
1896     assert (alloc->is_Allocate(), "storestore should point to AllocateNode");
1897     if (not_global_escape(alloc)) {
1898       MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
1899       mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
1900       mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
1901       igvn->register_new_node_with_optimizer(mb);
1902       igvn->replace_node(storestore, mb);
1903     }
1904   }
1905 }
1906 
1907 // Optimize objects compare.
1908 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
1909   assert(OptimizePtrCompare, "sanity");
1910   PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
1911   PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
1912   JavaObjectNode* jobj1 = unique_java_object(n->in(1));
1913   JavaObjectNode* jobj2 = unique_java_object(n->in(2));
1914   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
1915   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
1916 
1917   // Check simple cases first.
1918   if (jobj1 != NULL) {
1919     if (jobj1->escape_state() == PointsToNode::NoEscape) {
1920       if (jobj1 == jobj2) {
1921         // Comparing the same not escaping object.
1922         return _pcmp_eq;
1923       }
1924       Node* obj = jobj1->ideal_node();
1925       // Comparing not escaping allocation.
1926       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1927           !ptn2->points_to(jobj1)) {
1928         return _pcmp_neq; // This includes nullness check.
1929       }
1930     }
1931   }
1932   if (jobj2 != NULL) {
1933     if (jobj2->escape_state() == PointsToNode::NoEscape) {
1934       Node* obj = jobj2->ideal_node();
1935       // Comparing not escaping allocation.
1936       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1937           !ptn1->points_to(jobj2)) {
1938         return _pcmp_neq; // This includes nullness check.
1939       }
1940     }
1941   }
1942   if (jobj1 != NULL && jobj1 != phantom_obj &&
1943       jobj2 != NULL && jobj2 != phantom_obj &&
1944       jobj1->ideal_node()->is_Con() &&
1945       jobj2->ideal_node()->is_Con()) {
1946     // Klass or String constants compare. Need to be careful with
1947     // compressed pointers - compare types of ConN and ConP instead of nodes.
1948     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
1949     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
1950     if (t1->make_ptr() == t2->make_ptr()) {
1951       return _pcmp_eq;
1952     } else {
1953       return _pcmp_neq;
1954     }
1955   }
1956   if (ptn1->meet(ptn2)) {
1957     return NULL; // Sets are not disjoint
1958   }
1959 
1960   // Sets are disjoint.
1961   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
1962   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
1963   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
1964   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
1965   if (set1_has_unknown_ptr && set2_has_null_ptr ||
1966       set2_has_unknown_ptr && set1_has_null_ptr) {
1967     // Check nullness of unknown object.
1968     return NULL;
1969   }
1970 
1971   // Disjointness by itself is not sufficient since
1972   // alias analysis is not complete for escaped objects.
1973   // Disjoint sets are definitely unrelated only when
1974   // at least one set has only not escaping allocations.
1975   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
1976     if (ptn1->non_escaping_allocation()) {
1977       return _pcmp_neq;
1978     }
1979   }
1980   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
1981     if (ptn2->non_escaping_allocation()) {
1982       return _pcmp_neq;
1983     }
1984   }
1985   return NULL;
1986 }
1987 
1988 // Connection Graph constuction functions.
1989 
1990 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
1991   PointsToNode* ptadr = _nodes.at(n->_idx);
1992   if (ptadr != NULL) {
1993     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
1994     return;
1995   }
1996   Compile* C = _compile;
1997   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
1998   _nodes.at_put(n->_idx, ptadr);
1999 }
2000 
2001 void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
2002   PointsToNode* ptadr = _nodes.at(n->_idx);
2003   if (ptadr != NULL) {
2004     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
2005     return;
2006   }
2007   Compile* C = _compile;
2008   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
2009   _nodes.at_put(n->_idx, ptadr);
2010 }
2011 
2012 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
2013   PointsToNode* ptadr = _nodes.at(n->_idx);
2014   if (ptadr != NULL) {
2015     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
2016     return;
2017   }
2018   bool unsafe = false;
2019   bool is_oop = is_oop_field(n, offset, &unsafe);
2020   if (unsafe) {
2021     es = PointsToNode::GlobalEscape;
2022   }
2023   Compile* C = _compile;
2024   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
2025   _nodes.at_put(n->_idx, field);
2026 }
2027 
2028 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
2029                                     PointsToNode* src, PointsToNode* dst) {
2030   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
2031   assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
2032   PointsToNode* ptadr = _nodes.at(n->_idx);
2033   if (ptadr != NULL) {
2034     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
2035     return;
2036   }
2037   Compile* C = _compile;
2038   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
2039   _nodes.at_put(n->_idx, ptadr);
2040   // Add edge from arraycopy node to source object.
2041   (void)add_edge(ptadr, src);
2042   src->set_arraycopy_src();
2043   // Add edge from destination object to arraycopy node.
2044   (void)add_edge(dst, ptadr);
2045   dst->set_arraycopy_dst();
2046 }
2047 
2048 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
2049   const Type* adr_type = n->as_AddP()->bottom_type();
2050   BasicType bt = T_INT;
2051   if (offset == Type::OffsetBot) {
2052     // Check only oop fields.
2053     if (!adr_type->isa_aryptr() ||
2054         (adr_type->isa_aryptr()->klass() == NULL) ||
2055          adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
2056       // OffsetBot is used to reference array's element. Ignore first AddP.
2057       if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
2058         bt = T_OBJECT;
2059       }
2060     }
2061   } else if (offset != oopDesc::klass_offset_in_bytes()) {
2062     if (adr_type->isa_instptr()) {
2063       ciField* field = _compile->alias_type(adr_type->isa_instptr())->field();
2064       if (field != NULL) {
2065         bt = field->layout_type();
2066       } else {
2067         // Check for unsafe oop field access
2068         if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
2069           bt = T_OBJECT;
2070           (*unsafe) = true;
2071         }
2072       }
2073     } else if (adr_type->isa_aryptr()) {
2074       if (offset == arrayOopDesc::length_offset_in_bytes()) {
2075         // Ignore array length load.
2076       } else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
2077         // Ignore first AddP.
2078       } else {
2079         const Type* elemtype = adr_type->isa_aryptr()->elem();
2080         bt = elemtype->array_element_basic_type();
2081       }
2082     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
2083       // Allocation initialization, ThreadLocal field access, unsafe access
2084       if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
2085         bt = T_OBJECT;
2086       }
2087     }
2088   }
2089   return (bt == T_OBJECT || bt == T_NARROWOOP || bt == T_ARRAY);
2090 }
2091 
2092 // Returns unique pointed java object or NULL.
2093 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
2094   assert(!_collecting, "should not call when contructed graph");
2095   // If the node was created after the escape computation we can't answer.
2096   uint idx = n->_idx;
2097   if (idx >= nodes_size()) {
2098     return NULL;
2099   }
2100   PointsToNode* ptn = ptnode_adr(idx);
2101   if (ptn->is_JavaObject()) {
2102     return ptn->as_JavaObject();
2103   }
2104   assert(ptn->is_LocalVar(), "sanity");
2105   // Check all java objects it points to.
2106   JavaObjectNode* jobj = NULL;
2107   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2108     PointsToNode* e = i.get();
2109     if (e->is_JavaObject()) {
2110       if (jobj == NULL) {
2111         jobj = e->as_JavaObject();
2112       } else if (jobj != e) {
2113         return NULL;
2114       }
2115     }
2116   }
2117   return jobj;
2118 }
2119 
2120 // Return true if this node points only to non-escaping allocations.
2121 bool PointsToNode::non_escaping_allocation() {
2122   if (is_JavaObject()) {
2123     Node* n = ideal_node();
2124     if (n->is_Allocate() || n->is_CallStaticJava()) {
2125       return (escape_state() == PointsToNode::NoEscape);
2126     } else {
2127       return false;
2128     }
2129   }
2130   assert(is_LocalVar(), "sanity");
2131   // Check all java objects it points to.
2132   for (EdgeIterator i(this); i.has_next(); i.next()) {
2133     PointsToNode* e = i.get();
2134     if (e->is_JavaObject()) {
2135       Node* n = e->ideal_node();
2136       if ((e->escape_state() != PointsToNode::NoEscape) ||
2137           !(n->is_Allocate() || n->is_CallStaticJava())) {
2138         return false;
2139       }
2140     }
2141   }
2142   return true;
2143 }
2144 
2145 // Return true if we know the node does not escape globally.
2146 bool ConnectionGraph::not_global_escape(Node *n) {
2147   assert(!_collecting, "should not call during graph construction");
2148   // If the node was created after the escape computation we can't answer.
2149   uint idx = n->_idx;
2150   if (idx >= nodes_size()) {
2151     return false;
2152   }
2153   PointsToNode* ptn = ptnode_adr(idx);
2154   PointsToNode::EscapeState es = ptn->escape_state();
2155   // If we have already computed a value, return it.
2156   if (es >= PointsToNode::GlobalEscape)
2157     return false;
2158   if (ptn->is_JavaObject()) {
2159     return true; // (es < PointsToNode::GlobalEscape);
2160   }
2161   assert(ptn->is_LocalVar(), "sanity");
2162   // Check all java objects it points to.
2163   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2164     if (i.get()->escape_state() >= PointsToNode::GlobalEscape)
2165       return false;
2166   }
2167   return true;
2168 }
2169 
2170 
2171 // Helper functions
2172 
2173 // Return true if this node points to specified node or nodes it points to.
2174 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
2175   if (is_JavaObject()) {
2176     return (this == ptn);
2177   }
2178   assert(is_LocalVar() || is_Field(), "sanity");
2179   for (EdgeIterator i(this); i.has_next(); i.next()) {
2180     if (i.get() == ptn)
2181       return true;
2182   }
2183   return false;
2184 }
2185 
2186 // Return true if one node points to an other.
2187 bool PointsToNode::meet(PointsToNode* ptn) {
2188   if (this == ptn) {
2189     return true;
2190   } else if (ptn->is_JavaObject()) {
2191     return this->points_to(ptn->as_JavaObject());
2192   } else if (this->is_JavaObject()) {
2193     return ptn->points_to(this->as_JavaObject());
2194   }
2195   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
2196   int ptn_count =  ptn->edge_count();
2197   for (EdgeIterator i(this); i.has_next(); i.next()) {
2198     PointsToNode* this_e = i.get();
2199     for (int j = 0; j < ptn_count; j++) {
2200       if (this_e == ptn->edge(j))
2201         return true;
2202     }
2203   }
2204   return false;
2205 }
2206 
2207 #ifdef ASSERT
2208 // Return true if bases point to this java object.
2209 bool FieldNode::has_base(JavaObjectNode* jobj) const {
2210   for (BaseIterator i(this); i.has_next(); i.next()) {
2211     if (i.get() == jobj)
2212       return true;
2213   }
2214   return false;
2215 }
2216 #endif
2217 
2218 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
2219   const Type *adr_type = phase->type(adr);
2220   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
2221       adr->in(AddPNode::Address)->is_Proj() &&
2222       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
2223     // We are computing a raw address for a store captured by an Initialize
2224     // compute an appropriate address type. AddP cases #3 and #5 (see below).
2225     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
2226     assert(offs != Type::OffsetBot ||
2227            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
2228            "offset must be a constant or it is initialization of array");
2229     return offs;
2230   }
2231   const TypePtr *t_ptr = adr_type->isa_ptr();
2232   assert(t_ptr != NULL, "must be a pointer type");
2233   return t_ptr->offset();
2234 }
2235 
2236 Node* ConnectionGraph::get_addp_base(Node *addp) {
2237   assert(addp->is_AddP(), "must be AddP");
2238   //
2239   // AddP cases for Base and Address inputs:
2240   // case #1. Direct object's field reference:
2241   //     Allocate
2242   //       |
2243   //     Proj #5 ( oop result )
2244   //       |
2245   //     CheckCastPP (cast to instance type)
2246   //      | |
2247   //     AddP  ( base == address )
2248   //
2249   // case #2. Indirect object's field reference:
2250   //      Phi
2251   //       |
2252   //     CastPP (cast to instance type)
2253   //      | |
2254   //     AddP  ( base == address )
2255   //
2256   // case #3. Raw object's field reference for Initialize node:
2257   //      Allocate
2258   //        |
2259   //      Proj #5 ( oop result )
2260   //  top   |
2261   //     \  |
2262   //     AddP  ( base == top )
2263   //
2264   // case #4. Array's element reference:
2265   //   {CheckCastPP | CastPP}
2266   //     |  | |
2267   //     |  AddP ( array's element offset )
2268   //     |  |
2269   //     AddP ( array's offset )
2270   //
2271   // case #5. Raw object's field reference for arraycopy stub call:
2272   //          The inline_native_clone() case when the arraycopy stub is called
2273   //          after the allocation before Initialize and CheckCastPP nodes.
2274   //      Allocate
2275   //        |
2276   //      Proj #5 ( oop result )
2277   //       | |
2278   //       AddP  ( base == address )
2279   //
2280   // case #6. Constant Pool, ThreadLocal, CastX2P or
2281   //          Raw object's field reference:
2282   //      {ConP, ThreadLocal, CastX2P, raw Load}
2283   //  top   |
2284   //     \  |
2285   //     AddP  ( base == top )
2286   //
2287   // case #7. Klass's field reference.
2288   //      LoadKlass
2289   //       | |
2290   //       AddP  ( base == address )
2291   //
2292   // case #8. narrow Klass's field reference.
2293   //      LoadNKlass
2294   //       |
2295   //      DecodeN
2296   //       | |
2297   //       AddP  ( base == address )
2298   //
2299   Node *base = addp->in(AddPNode::Base);
2300   if (base->uncast()->is_top()) { // The AddP case #3 and #6.
2301     base = addp->in(AddPNode::Address);
2302     while (base->is_AddP()) {
2303       // Case #6 (unsafe access) may have several chained AddP nodes.
2304       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
2305       base = base->in(AddPNode::Address);
2306     }
2307     Node* uncast_base = base->uncast();
2308     int opcode = uncast_base->Opcode();
2309     assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
2310            opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
2311            (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
2312            (uncast_base->is_Proj() && uncast_base->in(0)->is_Allocate()), "sanity");
2313   }
2314   return base;
2315 }
2316 
2317 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
2318   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
2319   Node* addp2 = addp->raw_out(0);
2320   if (addp->outcnt() == 1 && addp2->is_AddP() &&
2321       addp2->in(AddPNode::Base) == n &&
2322       addp2->in(AddPNode::Address) == addp) {
2323     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
2324     //
2325     // Find array's offset to push it on worklist first and
2326     // as result process an array's element offset first (pushed second)
2327     // to avoid CastPP for the array's offset.
2328     // Otherwise the inserted CastPP (LocalVar) will point to what
2329     // the AddP (Field) points to. Which would be wrong since
2330     // the algorithm expects the CastPP has the same point as
2331     // as AddP's base CheckCastPP (LocalVar).
2332     //
2333     //    ArrayAllocation
2334     //     |
2335     //    CheckCastPP
2336     //     |
2337     //    memProj (from ArrayAllocation CheckCastPP)
2338     //     |  ||
2339     //     |  ||   Int (element index)
2340     //     |  ||    |   ConI (log(element size))
2341     //     |  ||    |   /
2342     //     |  ||   LShift
2343     //     |  ||  /
2344     //     |  AddP (array's element offset)
2345     //     |  |
2346     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
2347     //     | / /
2348     //     AddP (array's offset)
2349     //      |
2350     //     Load/Store (memory operation on array's element)
2351     //
2352     return addp2;
2353   }
2354   return NULL;
2355 }
2356 
2357 //
2358 // Adjust the type and inputs of an AddP which computes the
2359 // address of a field of an instance
2360 //
2361 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
2362   PhaseGVN* igvn = _igvn;
2363   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
2364   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
2365   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
2366   if (t == NULL) {
2367     // We are computing a raw address for a store captured by an Initialize
2368     // compute an appropriate address type (cases #3 and #5).
2369     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
2370     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
2371     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
2372     assert(offs != Type::OffsetBot, "offset must be a constant");
2373     t = base_t->add_offset(offs)->is_oopptr();
2374   }
2375   int inst_id =  base_t->instance_id();
2376   assert(!t->is_known_instance() || t->instance_id() == inst_id,
2377                              "old type must be non-instance or match new type");
2378 
2379   // The type 't' could be subclass of 'base_t'.
2380   // As result t->offset() could be large then base_t's size and it will
2381   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
2382   // constructor verifies correctness of the offset.
2383   //
2384   // It could happened on subclass's branch (from the type profiling
2385   // inlining) which was not eliminated during parsing since the exactness
2386   // of the allocation type was not propagated to the subclass type check.
2387   //
2388   // Or the type 't' could be not related to 'base_t' at all.
2389   // It could happened when CHA type is different from MDO type on a dead path
2390   // (for example, from instanceof check) which is not collapsed during parsing.
2391   //
2392   // Do nothing for such AddP node and don't process its users since
2393   // this code branch will go away.
2394   //
2395   if (!t->is_known_instance() &&
2396       !base_t->klass()->is_subtype_of(t->klass())) {
2397      return false; // bail out
2398   }
2399   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
2400   // Do NOT remove the next line: ensure a new alias index is allocated
2401   // for the instance type. Note: C++ will not remove it since the call
2402   // has side effect.
2403   int alias_idx = _compile->get_alias_index(tinst);
2404   igvn->set_type(addp, tinst);
2405   // record the allocation in the node map
2406   set_map(addp, get_map(base->_idx));
2407   // Set addp's Base and Address to 'base'.
2408   Node *abase = addp->in(AddPNode::Base);
2409   Node *adr   = addp->in(AddPNode::Address);
2410   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
2411       adr->in(0)->_idx == (uint)inst_id) {
2412     // Skip AddP cases #3 and #5.
2413   } else {
2414     assert(!abase->is_top(), "sanity"); // AddP case #3
2415     if (abase != base) {
2416       igvn->hash_delete(addp);
2417       addp->set_req(AddPNode::Base, base);
2418       if (abase == adr) {
2419         addp->set_req(AddPNode::Address, base);
2420       } else {
2421         // AddP case #4 (adr is array's element offset AddP node)
2422 #ifdef ASSERT
2423         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
2424         assert(adr->is_AddP() && atype != NULL &&
2425                atype->instance_id() == inst_id, "array's element offset should be processed first");
2426 #endif
2427       }
2428       igvn->hash_insert(addp);
2429     }
2430   }
2431   // Put on IGVN worklist since at least addp's type was changed above.
2432   record_for_optimizer(addp);
2433   return true;
2434 }
2435 
2436 //
2437 // Create a new version of orig_phi if necessary. Returns either the newly
2438 // created phi or an existing phi.  Sets create_new to indicate whether a new
2439 // phi was created.  Cache the last newly created phi in the node map.
2440 //
2441 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
2442   Compile *C = _compile;
2443   PhaseGVN* igvn = _igvn;
2444   new_created = false;
2445   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
2446   // nothing to do if orig_phi is bottom memory or matches alias_idx
2447   if (phi_alias_idx == alias_idx) {
2448     return orig_phi;
2449   }
2450   // Have we recently created a Phi for this alias index?
2451   PhiNode *result = get_map_phi(orig_phi->_idx);
2452   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
2453     return result;
2454   }
2455   // Previous check may fail when the same wide memory Phi was split into Phis
2456   // for different memory slices. Search all Phis for this region.
2457   if (result != NULL) {
2458     Node* region = orig_phi->in(0);
2459     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
2460       Node* phi = region->fast_out(i);
2461       if (phi->is_Phi() &&
2462           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
2463         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
2464         return phi->as_Phi();
2465       }
2466     }
2467   }
2468   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
2469     if (C->do_escape_analysis() == true && !C->failing()) {
2470       // Retry compilation without escape analysis.
2471       // If this is the first failure, the sentinel string will "stick"
2472       // to the Compile object, and the C2Compiler will see it and retry.
2473       C->record_failure(C2Compiler::retry_no_escape_analysis());
2474     }
2475     return NULL;
2476   }
2477   orig_phi_worklist.append_if_missing(orig_phi);
2478   const TypePtr *atype = C->get_adr_type(alias_idx);
2479   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
2480   C->copy_node_notes_to(result, orig_phi);
2481   igvn->set_type(result, result->bottom_type());
2482   record_for_optimizer(result);
2483   set_map(orig_phi, result);
2484   new_created = true;
2485   return result;
2486 }
2487 
2488 //
2489 // Return a new version of Memory Phi "orig_phi" with the inputs having the
2490 // specified alias index.
2491 //
2492 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist) {
2493   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
2494   Compile *C = _compile;
2495   PhaseGVN* igvn = _igvn;
2496   bool new_phi_created;
2497   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
2498   if (!new_phi_created) {
2499     return result;
2500   }
2501   GrowableArray<PhiNode *>  phi_list;
2502   GrowableArray<uint>  cur_input;
2503   PhiNode *phi = orig_phi;
2504   uint idx = 1;
2505   bool finished = false;
2506   while(!finished) {
2507     while (idx < phi->req()) {
2508       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist);
2509       if (mem != NULL && mem->is_Phi()) {
2510         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
2511         if (new_phi_created) {
2512           // found an phi for which we created a new split, push current one on worklist and begin
2513           // processing new one
2514           phi_list.push(phi);
2515           cur_input.push(idx);
2516           phi = mem->as_Phi();
2517           result = newphi;
2518           idx = 1;
2519           continue;
2520         } else {
2521           mem = newphi;
2522         }
2523       }
2524       if (C->failing()) {
2525         return NULL;
2526       }
2527       result->set_req(idx++, mem);
2528     }
2529 #ifdef ASSERT
2530     // verify that the new Phi has an input for each input of the original
2531     assert( phi->req() == result->req(), "must have same number of inputs.");
2532     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
2533 #endif
2534     // Check if all new phi's inputs have specified alias index.
2535     // Otherwise use old phi.
2536     for (uint i = 1; i < phi->req(); i++) {
2537       Node* in = result->in(i);
2538       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
2539     }
2540     // we have finished processing a Phi, see if there are any more to do
2541     finished = (phi_list.length() == 0 );
2542     if (!finished) {
2543       phi = phi_list.pop();
2544       idx = cur_input.pop();
2545       PhiNode *prev_result = get_map_phi(phi->_idx);
2546       prev_result->set_req(idx++, result);
2547       result = prev_result;
2548     }
2549   }
2550   return result;
2551 }
2552 
2553 //
2554 // The next methods are derived from methods in MemNode.
2555 //
2556 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
2557   Node *mem = mmem;
2558   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
2559   // means an array I have not precisely typed yet.  Do not do any
2560   // alias stuff with it any time soon.
2561   if (toop->base() != Type::AnyPtr &&
2562       !(toop->klass() != NULL &&
2563         toop->klass()->is_java_lang_Object() &&
2564         toop->offset() == Type::OffsetBot)) {
2565     mem = mmem->memory_at(alias_idx);
2566     // Update input if it is progress over what we have now
2567   }
2568   return mem;
2569 }
2570 
2571 //
2572 // Move memory users to their memory slices.
2573 //
2574 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
2575   Compile* C = _compile;
2576   PhaseGVN* igvn = _igvn;
2577   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
2578   assert(tp != NULL, "ptr type");
2579   int alias_idx = C->get_alias_index(tp);
2580   int general_idx = C->get_general_index(alias_idx);
2581 
2582   // Move users first
2583   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2584     Node* use = n->fast_out(i);
2585     if (use->is_MergeMem()) {
2586       MergeMemNode* mmem = use->as_MergeMem();
2587       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
2588       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
2589         continue; // Nothing to do
2590       }
2591       // Replace previous general reference to mem node.
2592       uint orig_uniq = C->unique();
2593       Node* m = find_inst_mem(n, general_idx, orig_phis);
2594       assert(orig_uniq == C->unique(), "no new nodes");
2595       mmem->set_memory_at(general_idx, m);
2596       --imax;
2597       --i;
2598     } else if (use->is_MemBar()) {
2599       assert(!use->is_Initialize(), "initializing stores should not be moved");
2600       if (use->req() > MemBarNode::Precedent &&
2601           use->in(MemBarNode::Precedent) == n) {
2602         // Don't move related membars.
2603         record_for_optimizer(use);
2604         continue;
2605       }
2606       tp = use->as_MemBar()->adr_type()->isa_ptr();
2607       if (tp != NULL && C->get_alias_index(tp) == alias_idx ||
2608           alias_idx == general_idx) {
2609         continue; // Nothing to do
2610       }
2611       // Move to general memory slice.
2612       uint orig_uniq = C->unique();
2613       Node* m = find_inst_mem(n, general_idx, orig_phis);
2614       assert(orig_uniq == C->unique(), "no new nodes");
2615       igvn->hash_delete(use);
2616       imax -= use->replace_edge(n, m);
2617       igvn->hash_insert(use);
2618       record_for_optimizer(use);
2619       --i;
2620 #ifdef ASSERT
2621     } else if (use->is_Mem()) {
2622       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
2623         // Don't move related cardmark.
2624         continue;
2625       }
2626       // Memory nodes should have new memory input.
2627       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
2628       assert(tp != NULL, "ptr type");
2629       int idx = C->get_alias_index(tp);
2630       assert(get_map(use->_idx) != NULL || idx == alias_idx,
2631              "Following memory nodes should have new memory input or be on the same memory slice");
2632     } else if (use->is_Phi()) {
2633       // Phi nodes should be split and moved already.
2634       tp = use->as_Phi()->adr_type()->isa_ptr();
2635       assert(tp != NULL, "ptr type");
2636       int idx = C->get_alias_index(tp);
2637       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
2638     } else {
2639       use->dump();
2640       assert(false, "should not be here");
2641 #endif
2642     }
2643   }
2644 }
2645 
2646 //
2647 // Search memory chain of "mem" to find a MemNode whose address
2648 // is the specified alias index.
2649 //
2650 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis) {
2651   if (orig_mem == NULL)
2652     return orig_mem;
2653   Compile* C = _compile;
2654   PhaseGVN* igvn = _igvn;
2655   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
2656   bool is_instance = (toop != NULL) && toop->is_known_instance();
2657   Node *start_mem = C->start()->proj_out(TypeFunc::Memory);
2658   Node *prev = NULL;
2659   Node *result = orig_mem;
2660   while (prev != result) {
2661     prev = result;
2662     if (result == start_mem)
2663       break;  // hit one of our sentinels
2664     if (result->is_Mem()) {
2665       const Type *at = igvn->type(result->in(MemNode::Address));
2666       if (at == Type::TOP)
2667         break; // Dead
2668       assert (at->isa_ptr() != NULL, "pointer type required.");
2669       int idx = C->get_alias_index(at->is_ptr());
2670       if (idx == alias_idx)
2671         break; // Found
2672       if (!is_instance && (at->isa_oopptr() == NULL ||
2673                            !at->is_oopptr()->is_known_instance())) {
2674         break; // Do not skip store to general memory slice.
2675       }
2676       result = result->in(MemNode::Memory);
2677     }
2678     if (!is_instance)
2679       continue;  // don't search further for non-instance types
2680     // skip over a call which does not affect this memory slice
2681     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
2682       Node *proj_in = result->in(0);
2683       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
2684         break;  // hit one of our sentinels
2685       } else if (proj_in->is_Call()) {
2686         // ArrayCopy node processed here as well
2687         CallNode *call = proj_in->as_Call();
2688         if (!call->may_modify(toop, igvn)) {
2689           result = call->in(TypeFunc::Memory);
2690         }
2691       } else if (proj_in->is_Initialize()) {
2692         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
2693         // Stop if this is the initialization for the object instance which
2694         // which contains this memory slice, otherwise skip over it.
2695         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
2696           result = proj_in->in(TypeFunc::Memory);
2697         }
2698       } else if (proj_in->is_MemBar()) {
2699         if (proj_in->in(TypeFunc::Memory)->is_MergeMem() &&
2700             proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->is_Proj() &&
2701             proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->is_ArrayCopy()) {
2702           // clone
2703           ArrayCopyNode* ac = proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->as_ArrayCopy();
2704           if (ac->may_modify(toop, igvn)) {
2705             break;
2706           }
2707         }
2708         result = proj_in->in(TypeFunc::Memory);
2709       }
2710     } else if (result->is_MergeMem()) {
2711       MergeMemNode *mmem = result->as_MergeMem();
2712       result = step_through_mergemem(mmem, alias_idx, toop);
2713       if (result == mmem->base_memory()) {
2714         // Didn't find instance memory, search through general slice recursively.
2715         result = mmem->memory_at(C->get_general_index(alias_idx));
2716         result = find_inst_mem(result, alias_idx, orig_phis);
2717         if (C->failing()) {
2718           return NULL;
2719         }
2720         mmem->set_memory_at(alias_idx, result);
2721       }
2722     } else if (result->is_Phi() &&
2723                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
2724       Node *un = result->as_Phi()->unique_input(igvn);
2725       if (un != NULL) {
2726         orig_phis.append_if_missing(result->as_Phi());
2727         result = un;
2728       } else {
2729         break;
2730       }
2731     } else if (result->is_ClearArray()) {
2732       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
2733         // Can not bypass initialization of the instance
2734         // we are looking for.
2735         break;
2736       }
2737       // Otherwise skip it (the call updated 'result' value).
2738     } else if (result->Opcode() == Op_SCMemProj) {
2739       Node* mem = result->in(0);
2740       Node* adr = NULL;
2741       if (mem->is_LoadStore()) {
2742         adr = mem->in(MemNode::Address);
2743       } else {
2744         assert(mem->Opcode() == Op_EncodeISOArray ||
2745                mem->Opcode() == Op_StrCompressedCopy, "sanity");
2746         adr = mem->in(3); // Memory edge corresponds to destination array
2747       }
2748       const Type *at = igvn->type(adr);
2749       if (at != Type::TOP) {
2750         assert(at->isa_ptr() != NULL, "pointer type required.");
2751         int idx = C->get_alias_index(at->is_ptr());
2752         if (idx == alias_idx) {
2753           // Assert in debug mode
2754           assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
2755           break; // In product mode return SCMemProj node
2756         }
2757       }
2758       result = mem->in(MemNode::Memory);
2759     } else if (result->Opcode() == Op_StrInflatedCopy) {
2760       Node* adr = result->in(3); // Memory edge corresponds to destination array
2761       const Type *at = igvn->type(adr);
2762       if (at != Type::TOP) {
2763         assert(at->isa_ptr() != NULL, "pointer type required.");
2764         int idx = C->get_alias_index(at->is_ptr());
2765         if (idx == alias_idx) {
2766           // Assert in debug mode
2767           assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
2768           break; // In product mode return SCMemProj node
2769         }
2770       }
2771       result = result->in(MemNode::Memory);
2772     }
2773   }
2774   if (result->is_Phi()) {
2775     PhiNode *mphi = result->as_Phi();
2776     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
2777     const TypePtr *t = mphi->adr_type();
2778     if (!is_instance) {
2779       // Push all non-instance Phis on the orig_phis worklist to update inputs
2780       // during Phase 4 if needed.
2781       orig_phis.append_if_missing(mphi);
2782     } else if (C->get_alias_index(t) != alias_idx) {
2783       // Create a new Phi with the specified alias index type.
2784       result = split_memory_phi(mphi, alias_idx, orig_phis);
2785     }
2786   }
2787   // the result is either MemNode, PhiNode, InitializeNode.
2788   return result;
2789 }
2790 
2791 //
2792 //  Convert the types of unescaped object to instance types where possible,
2793 //  propagate the new type information through the graph, and update memory
2794 //  edges and MergeMem inputs to reflect the new type.
2795 //
2796 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
2797 //  The processing is done in 4 phases:
2798 //
2799 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
2800 //            types for the CheckCastPP for allocations where possible.
2801 //            Propagate the new types through users as follows:
2802 //               casts and Phi:  push users on alloc_worklist
2803 //               AddP:  cast Base and Address inputs to the instance type
2804 //                      push any AddP users on alloc_worklist and push any memnode
2805 //                      users onto memnode_worklist.
2806 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
2807 //            search the Memory chain for a store with the appropriate type
2808 //            address type.  If a Phi is found, create a new version with
2809 //            the appropriate memory slices from each of the Phi inputs.
2810 //            For stores, process the users as follows:
2811 //               MemNode:  push on memnode_worklist
2812 //               MergeMem: push on mergemem_worklist
2813 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
2814 //            moving the first node encountered of each  instance type to the
2815 //            the input corresponding to its alias index.
2816 //            appropriate memory slice.
2817 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
2818 //
2819 // In the following example, the CheckCastPP nodes are the cast of allocation
2820 // results and the allocation of node 29 is unescaped and eligible to be an
2821 // instance type.
2822 //
2823 // We start with:
2824 //
2825 //     7 Parm #memory
2826 //    10  ConI  "12"
2827 //    19  CheckCastPP   "Foo"
2828 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2829 //    29  CheckCastPP   "Foo"
2830 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
2831 //
2832 //    40  StoreP  25   7  20   ... alias_index=4
2833 //    50  StoreP  35  40  30   ... alias_index=4
2834 //    60  StoreP  45  50  20   ... alias_index=4
2835 //    70  LoadP    _  60  30   ... alias_index=4
2836 //    80  Phi     75  50  60   Memory alias_index=4
2837 //    90  LoadP    _  80  30   ... alias_index=4
2838 //   100  LoadP    _  80  20   ... alias_index=4
2839 //
2840 //
2841 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
2842 // and creating a new alias index for node 30.  This gives:
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"  iid=24
2849 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2850 //
2851 //    40  StoreP  25   7  20   ... alias_index=4
2852 //    50  StoreP  35  40  30   ... alias_index=6
2853 //    60  StoreP  45  50  20   ... alias_index=4
2854 //    70  LoadP    _  60  30   ... alias_index=6
2855 //    80  Phi     75  50  60   Memory alias_index=4
2856 //    90  LoadP    _  80  30   ... alias_index=6
2857 //   100  LoadP    _  80  20   ... alias_index=4
2858 //
2859 // In phase 2, new memory inputs are computed for the loads and stores,
2860 // And a new version of the phi is created.  In phase 4, the inputs to
2861 // node 80 are updated and then the memory nodes are updated with the
2862 // values computed in phase 2.  This results in:
2863 //
2864 //     7 Parm #memory
2865 //    10  ConI  "12"
2866 //    19  CheckCastPP   "Foo"
2867 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2868 //    29  CheckCastPP   "Foo"  iid=24
2869 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2870 //
2871 //    40  StoreP  25  7   20   ... alias_index=4
2872 //    50  StoreP  35  7   30   ... alias_index=6
2873 //    60  StoreP  45  40  20   ... alias_index=4
2874 //    70  LoadP    _  50  30   ... alias_index=6
2875 //    80  Phi     75  40  60   Memory alias_index=4
2876 //   120  Phi     75  50  50   Memory alias_index=6
2877 //    90  LoadP    _ 120  30   ... alias_index=6
2878 //   100  LoadP    _  80  20   ... alias_index=4
2879 //
2880 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist, GrowableArray<ArrayCopyNode*> &arraycopy_worklist) {
2881   GrowableArray<Node *>  memnode_worklist;
2882   GrowableArray<PhiNode *>  orig_phis;
2883   PhaseIterGVN  *igvn = _igvn;
2884   uint new_index_start = (uint) _compile->num_alias_types();
2885   Arena* arena = Thread::current()->resource_area();
2886   VectorSet visited(arena);
2887   ideal_nodes.clear(); // Reset for use with set_map/get_map.
2888   uint unique_old = _compile->unique();
2889 
2890   //  Phase 1:  Process possible allocations from alloc_worklist.
2891   //  Create instance types for the CheckCastPP for allocations where possible.
2892   //
2893   // (Note: don't forget to change the order of the second AddP node on
2894   //  the alloc_worklist if the order of the worklist processing is changed,
2895   //  see the comment in find_second_addp().)
2896   //
2897   while (alloc_worklist.length() != 0) {
2898     Node *n = alloc_worklist.pop();
2899     uint ni = n->_idx;
2900     if (n->is_Call()) {
2901       CallNode *alloc = n->as_Call();
2902       // copy escape information to call node
2903       PointsToNode* ptn = ptnode_adr(alloc->_idx);
2904       PointsToNode::EscapeState es = ptn->escape_state();
2905       // We have an allocation or call which returns a Java object,
2906       // see if it is unescaped.
2907       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
2908         continue;
2909       // Find CheckCastPP for the allocate or for the return value of a call
2910       n = alloc->result_cast();
2911       if (n == NULL) {            // No uses except Initialize node
2912         if (alloc->is_Allocate()) {
2913           // Set the scalar_replaceable flag for allocation
2914           // so it could be eliminated if it has no uses.
2915           alloc->as_Allocate()->_is_scalar_replaceable = true;
2916         }
2917         if (alloc->is_CallStaticJava()) {
2918           // Set the scalar_replaceable flag for boxing method
2919           // so it could be eliminated if it has no uses.
2920           alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2921         }
2922         continue;
2923       }
2924       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
2925         assert(!alloc->is_Allocate(), "allocation should have unique type");
2926         continue;
2927       }
2928 
2929       // The inline code for Object.clone() casts the allocation result to
2930       // java.lang.Object and then to the actual type of the allocated
2931       // object. Detect this case and use the second cast.
2932       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
2933       // the allocation result is cast to java.lang.Object and then
2934       // to the actual Array type.
2935       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
2936           && (alloc->is_AllocateArray() ||
2937               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
2938         Node *cast2 = NULL;
2939         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2940           Node *use = n->fast_out(i);
2941           if (use->is_CheckCastPP()) {
2942             cast2 = use;
2943             break;
2944           }
2945         }
2946         if (cast2 != NULL) {
2947           n = cast2;
2948         } else {
2949           // Non-scalar replaceable if the allocation type is unknown statically
2950           // (reflection allocation), the object can't be restored during
2951           // deoptimization without precise type.
2952           continue;
2953         }
2954       }
2955 
2956       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
2957       if (t == NULL)
2958         continue;  // not a TypeOopPtr
2959       if (!t->klass_is_exact())
2960         continue; // not an unique type
2961 
2962       if (alloc->is_Allocate()) {
2963         // Set the scalar_replaceable flag for allocation
2964         // so it could be eliminated.
2965         alloc->as_Allocate()->_is_scalar_replaceable = true;
2966       }
2967       if (alloc->is_CallStaticJava()) {
2968         // Set the scalar_replaceable flag for boxing method
2969         // so it could be eliminated.
2970         alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2971       }
2972       set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
2973       // in order for an object to be scalar-replaceable, it must be:
2974       //   - a direct allocation (not a call returning an object)
2975       //   - non-escaping
2976       //   - eligible to be a unique type
2977       //   - not determined to be ineligible by escape analysis
2978       set_map(alloc, n);
2979       set_map(n, alloc);
2980       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
2981       igvn->hash_delete(n);
2982       igvn->set_type(n,  tinst);
2983       n->raise_bottom_type(tinst);
2984       igvn->hash_insert(n);
2985       record_for_optimizer(n);
2986       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
2987 
2988         // First, put on the worklist all Field edges from Connection Graph
2989         // which is more accurate than putting immediate users from Ideal Graph.
2990         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
2991           PointsToNode* tgt = e.get();
2992           if (tgt->is_Arraycopy()) {
2993             continue;
2994           }
2995           Node* use = tgt->ideal_node();
2996           assert(tgt->is_Field() && use->is_AddP(),
2997                  "only AddP nodes are Field edges in CG");
2998           if (use->outcnt() > 0) { // Don't process dead nodes
2999             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
3000             if (addp2 != NULL) {
3001               assert(alloc->is_AllocateArray(),"array allocation was expected");
3002               alloc_worklist.append_if_missing(addp2);
3003             }
3004             alloc_worklist.append_if_missing(use);
3005           }
3006         }
3007 
3008         // An allocation may have an Initialize which has raw stores. Scan
3009         // the users of the raw allocation result and push AddP users
3010         // on alloc_worklist.
3011         Node *raw_result = alloc->proj_out(TypeFunc::Parms);
3012         assert (raw_result != NULL, "must have an allocation result");
3013         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
3014           Node *use = raw_result->fast_out(i);
3015           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
3016             Node* addp2 = find_second_addp(use, raw_result);
3017             if (addp2 != NULL) {
3018               assert(alloc->is_AllocateArray(),"array allocation was expected");
3019               alloc_worklist.append_if_missing(addp2);
3020             }
3021             alloc_worklist.append_if_missing(use);
3022           } else if (use->is_MemBar()) {
3023             memnode_worklist.append_if_missing(use);
3024           }
3025         }
3026       }
3027     } else if (n->is_AddP()) {
3028       JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
3029       if (jobj == NULL || jobj == phantom_obj) {
3030 #ifdef ASSERT
3031         ptnode_adr(get_addp_base(n)->_idx)->dump();
3032         ptnode_adr(n->_idx)->dump();
3033         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3034 #endif
3035         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3036         return;
3037       }
3038       Node *base = get_map(jobj->idx());  // CheckCastPP node
3039       if (!split_AddP(n, base)) continue; // wrong type from dead path
3040     } else if (n->is_Phi() ||
3041                n->is_CheckCastPP() ||
3042                n->is_EncodeP() ||
3043                n->is_DecodeN() ||
3044                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
3045       if (visited.test_set(n->_idx)) {
3046         assert(n->is_Phi(), "loops only through Phi's");
3047         continue;  // already processed
3048       }
3049       JavaObjectNode* jobj = unique_java_object(n);
3050       if (jobj == NULL || jobj == phantom_obj) {
3051 #ifdef ASSERT
3052         ptnode_adr(n->_idx)->dump();
3053         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3054 #endif
3055         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3056         return;
3057       } else {
3058         Node *val = get_map(jobj->idx());   // CheckCastPP node
3059         TypeNode *tn = n->as_Type();
3060         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
3061         assert(tinst != NULL && tinst->is_known_instance() &&
3062                tinst->instance_id() == jobj->idx() , "instance type expected.");
3063 
3064         const Type *tn_type = igvn->type(tn);
3065         const TypeOopPtr *tn_t;
3066         if (tn_type->isa_narrowoop()) {
3067           tn_t = tn_type->make_ptr()->isa_oopptr();
3068         } else {
3069           tn_t = tn_type->isa_oopptr();
3070         }
3071         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
3072           if (tn_type->isa_narrowoop()) {
3073             tn_type = tinst->make_narrowoop();
3074           } else {
3075             tn_type = tinst;
3076           }
3077           igvn->hash_delete(tn);
3078           igvn->set_type(tn, tn_type);
3079           tn->set_type(tn_type);
3080           igvn->hash_insert(tn);
3081           record_for_optimizer(n);
3082         } else {
3083           assert(tn_type == TypePtr::NULL_PTR ||
3084                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
3085                  "unexpected type");
3086           continue; // Skip dead path with different type
3087         }
3088       }
3089     } else {
3090       debug_only(n->dump();)
3091       assert(false, "EA: unexpected node");
3092       continue;
3093     }
3094     // push allocation's users on appropriate worklist
3095     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3096       Node *use = n->fast_out(i);
3097       if(use->is_Mem() && use->in(MemNode::Address) == n) {
3098         // Load/store to instance's field
3099         memnode_worklist.append_if_missing(use);
3100       } else if (use->is_MemBar()) {
3101         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3102           memnode_worklist.append_if_missing(use);
3103         }
3104       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
3105         Node* addp2 = find_second_addp(use, n);
3106         if (addp2 != NULL) {
3107           alloc_worklist.append_if_missing(addp2);
3108         }
3109         alloc_worklist.append_if_missing(use);
3110       } else if (use->is_Phi() ||
3111                  use->is_CheckCastPP() ||
3112                  use->is_EncodeNarrowPtr() ||
3113                  use->is_DecodeNarrowPtr() ||
3114                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
3115         alloc_worklist.append_if_missing(use);
3116 #ifdef ASSERT
3117       } else if (use->is_Mem()) {
3118         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
3119       } else if (use->is_MergeMem()) {
3120         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3121       } else if (use->is_SafePoint()) {
3122         // Look for MergeMem nodes for calls which reference unique allocation
3123         // (through CheckCastPP nodes) even for debug info.
3124         Node* m = use->in(TypeFunc::Memory);
3125         if (m->is_MergeMem()) {
3126           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3127         }
3128       } else if (use->Opcode() == Op_EncodeISOArray) {
3129         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3130           // EncodeISOArray overwrites destination array
3131           memnode_worklist.append_if_missing(use);
3132         }
3133       } else {
3134         uint op = use->Opcode();
3135         if ((use->in(MemNode::Memory) == n) &&
3136             (op == Op_StrCompressedCopy || op == Op_StrInflatedCopy)) {
3137           // They overwrite memory edge corresponding to destination array,
3138           memnode_worklist.append_if_missing(use);
3139         } else if (!(op == Op_CmpP || op == Op_Conv2B ||
3140               op == Op_CastP2X || op == Op_StoreCM ||
3141               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp || op == Op_HasNegatives ||
3142               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
3143               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar)) {
3144           n->dump();
3145           use->dump();
3146           assert(false, "EA: missing allocation reference path");
3147         }
3148 #endif
3149       }
3150     }
3151 
3152   }
3153 
3154   // Go over all ArrayCopy nodes and if one of the inputs has a unique
3155   // type, record it in the ArrayCopy node so we know what memory this
3156   // node uses/modified.
3157   for (int next = 0; next < arraycopy_worklist.length(); next++) {
3158     ArrayCopyNode* ac = arraycopy_worklist.at(next);
3159     Node* dest = ac->in(ArrayCopyNode::Dest);
3160     if (dest->is_AddP()) {
3161       dest = get_addp_base(dest);
3162     }
3163     JavaObjectNode* jobj = unique_java_object(dest);
3164     if (jobj != NULL) {
3165       Node *base = get_map(jobj->idx());
3166       if (base != NULL) {
3167         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3168         ac->_dest_type = base_t;
3169       }
3170     }
3171     Node* src = ac->in(ArrayCopyNode::Src);
3172     if (src->is_AddP()) {
3173       src = get_addp_base(src);
3174     }
3175     jobj = unique_java_object(src);
3176     if (jobj != NULL) {
3177       Node* base = get_map(jobj->idx());
3178       if (base != NULL) {
3179         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3180         ac->_src_type = base_t;
3181       }
3182     }
3183   }
3184 
3185   // New alias types were created in split_AddP().
3186   uint new_index_end = (uint) _compile->num_alias_types();
3187   assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
3188 
3189   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
3190   //            compute new values for Memory inputs  (the Memory inputs are not
3191   //            actually updated until phase 4.)
3192   if (memnode_worklist.length() == 0)
3193     return;  // nothing to do
3194   while (memnode_worklist.length() != 0) {
3195     Node *n = memnode_worklist.pop();
3196     if (visited.test_set(n->_idx))
3197       continue;
3198     if (n->is_Phi() || n->is_ClearArray()) {
3199       // we don't need to do anything, but the users must be pushed
3200     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
3201       // we don't need to do anything, but the users must be pushed
3202       n = n->as_MemBar()->proj_out(TypeFunc::Memory);
3203       if (n == NULL)
3204         continue;
3205     } else if (n->Opcode() == Op_StrCompressedCopy ||
3206                n->Opcode() == Op_EncodeISOArray) {
3207       // get the memory projection
3208       n = n->find_out_with(Op_SCMemProj);
3209       assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3210     } else {
3211       assert(n->is_Mem(), "memory node required.");
3212       Node *addr = n->in(MemNode::Address);
3213       const Type *addr_t = igvn->type(addr);
3214       if (addr_t == Type::TOP)
3215         continue;
3216       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
3217       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
3218       assert ((uint)alias_idx < new_index_end, "wrong alias index");
3219       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
3220       if (_compile->failing()) {
3221         return;
3222       }
3223       if (mem != n->in(MemNode::Memory)) {
3224         // We delay the memory edge update since we need old one in
3225         // MergeMem code below when instances memory slices are separated.
3226         set_map(n, mem);
3227       }
3228       if (n->is_Load()) {
3229         continue;  // don't push users
3230       } else if (n->is_LoadStore()) {
3231         // get the memory projection
3232         n = n->find_out_with(Op_SCMemProj);
3233         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3234       }
3235     }
3236     // push user on appropriate worklist
3237     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3238       Node *use = n->fast_out(i);
3239       if (use->is_Phi() || use->is_ClearArray()) {
3240         memnode_worklist.append_if_missing(use);
3241       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
3242         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
3243           continue;
3244         memnode_worklist.append_if_missing(use);
3245       } else if (use->is_MemBar()) {
3246         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3247           memnode_worklist.append_if_missing(use);
3248         }
3249 #ifdef ASSERT
3250       } else if(use->is_Mem()) {
3251         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
3252       } else if (use->is_MergeMem()) {
3253         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3254       } else if (use->Opcode() == Op_EncodeISOArray) {
3255         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3256           // EncodeISOArray overwrites destination array
3257           memnode_worklist.append_if_missing(use);
3258         }
3259       } else {
3260         uint op = use->Opcode();
3261         if ((use->in(MemNode::Memory) == n) &&
3262             (op == Op_StrCompressedCopy || op == Op_StrInflatedCopy)) {
3263           // They overwrite memory edge corresponding to destination array,
3264           memnode_worklist.append_if_missing(use);
3265         } else if (!(op == Op_StoreCM ||
3266               (op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&
3267                strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||
3268               op == Op_AryEq || op == Op_StrComp || op == Op_HasNegatives ||
3269               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
3270               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar)) {
3271           n->dump();
3272           use->dump();
3273           assert(false, "EA: missing memory path");
3274         }
3275 #endif
3276       }
3277     }
3278   }
3279 
3280   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
3281   //            Walk each memory slice moving the first node encountered of each
3282   //            instance type to the the input corresponding to its alias index.
3283   uint length = _mergemem_worklist.length();
3284   for( uint next = 0; next < length; ++next ) {
3285     MergeMemNode* nmm = _mergemem_worklist.at(next);
3286     assert(!visited.test_set(nmm->_idx), "should not be visited before");
3287     // Note: we don't want to use MergeMemStream here because we only want to
3288     // scan inputs which exist at the start, not ones we add during processing.
3289     // Note 2: MergeMem may already contains instance memory slices added
3290     // during find_inst_mem() call when memory nodes were processed above.
3291     igvn->hash_delete(nmm);
3292     uint nslices = MIN2(nmm->req(), new_index_start);
3293     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
3294       Node* mem = nmm->in(i);
3295       Node* cur = NULL;
3296       if (mem == NULL || mem->is_top())
3297         continue;
3298       // First, update mergemem by moving memory nodes to corresponding slices
3299       // if their type became more precise since this mergemem was created.
3300       while (mem->is_Mem()) {
3301         const Type *at = igvn->type(mem->in(MemNode::Address));
3302         if (at != Type::TOP) {
3303           assert (at->isa_ptr() != NULL, "pointer type required.");
3304           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
3305           if (idx == i) {
3306             if (cur == NULL)
3307               cur = mem;
3308           } else {
3309             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
3310               nmm->set_memory_at(idx, mem);
3311             }
3312           }
3313         }
3314         mem = mem->in(MemNode::Memory);
3315       }
3316       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
3317       // Find any instance of the current type if we haven't encountered
3318       // already a memory slice of the instance along the memory chain.
3319       for (uint ni = new_index_start; ni < new_index_end; ni++) {
3320         if((uint)_compile->get_general_index(ni) == i) {
3321           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
3322           if (nmm->is_empty_memory(m)) {
3323             Node* result = find_inst_mem(mem, ni, orig_phis);
3324             if (_compile->failing()) {
3325               return;
3326             }
3327             nmm->set_memory_at(ni, result);
3328           }
3329         }
3330       }
3331     }
3332     // Find the rest of instances values
3333     for (uint ni = new_index_start; ni < new_index_end; ni++) {
3334       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
3335       Node* result = step_through_mergemem(nmm, ni, tinst);
3336       if (result == nmm->base_memory()) {
3337         // Didn't find instance memory, search through general slice recursively.
3338         result = nmm->memory_at(_compile->get_general_index(ni));
3339         result = find_inst_mem(result, ni, orig_phis);
3340         if (_compile->failing()) {
3341           return;
3342         }
3343         nmm->set_memory_at(ni, result);
3344       }
3345     }
3346     igvn->hash_insert(nmm);
3347     record_for_optimizer(nmm);
3348   }
3349 
3350   //  Phase 4:  Update the inputs of non-instance memory Phis and
3351   //            the Memory input of memnodes
3352   // First update the inputs of any non-instance Phi's from
3353   // which we split out an instance Phi.  Note we don't have
3354   // to recursively process Phi's encounted on the input memory
3355   // chains as is done in split_memory_phi() since they  will
3356   // also be processed here.
3357   for (int j = 0; j < orig_phis.length(); j++) {
3358     PhiNode *phi = orig_phis.at(j);
3359     int alias_idx = _compile->get_alias_index(phi->adr_type());
3360     igvn->hash_delete(phi);
3361     for (uint i = 1; i < phi->req(); i++) {
3362       Node *mem = phi->in(i);
3363       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
3364       if (_compile->failing()) {
3365         return;
3366       }
3367       if (mem != new_mem) {
3368         phi->set_req(i, new_mem);
3369       }
3370     }
3371     igvn->hash_insert(phi);
3372     record_for_optimizer(phi);
3373   }
3374 
3375   // Update the memory inputs of MemNodes with the value we computed
3376   // in Phase 2 and move stores memory users to corresponding memory slices.
3377   // Disable memory split verification code until the fix for 6984348.
3378   // Currently it produces false negative results since it does not cover all cases.
3379 #if 0 // ifdef ASSERT
3380   visited.Reset();
3381   Node_Stack old_mems(arena, _compile->unique() >> 2);
3382 #endif
3383   for (uint i = 0; i < ideal_nodes.size(); i++) {
3384     Node*    n = ideal_nodes.at(i);
3385     Node* nmem = get_map(n->_idx);
3386     assert(nmem != NULL, "sanity");
3387     if (n->is_Mem()) {
3388 #if 0 // ifdef ASSERT
3389       Node* old_mem = n->in(MemNode::Memory);
3390       if (!visited.test_set(old_mem->_idx)) {
3391         old_mems.push(old_mem, old_mem->outcnt());
3392       }
3393 #endif
3394       assert(n->in(MemNode::Memory) != nmem, "sanity");
3395       if (!n->is_Load()) {
3396         // Move memory users of a store first.
3397         move_inst_mem(n, orig_phis);
3398       }
3399       // Now update memory input
3400       igvn->hash_delete(n);
3401       n->set_req(MemNode::Memory, nmem);
3402       igvn->hash_insert(n);
3403       record_for_optimizer(n);
3404     } else {
3405       assert(n->is_Allocate() || n->is_CheckCastPP() ||
3406              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
3407     }
3408   }
3409 #if 0 // ifdef ASSERT
3410   // Verify that memory was split correctly
3411   while (old_mems.is_nonempty()) {
3412     Node* old_mem = old_mems.node();
3413     uint  old_cnt = old_mems.index();
3414     old_mems.pop();
3415     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
3416   }
3417 #endif
3418 }
3419 
3420 #ifndef PRODUCT
3421 static const char *node_type_names[] = {
3422   "UnknownType",
3423   "JavaObject",
3424   "LocalVar",
3425   "Field",
3426   "Arraycopy"
3427 };
3428 
3429 static const char *esc_names[] = {
3430   "UnknownEscape",
3431   "NoEscape",
3432   "ArgEscape",
3433   "GlobalEscape"
3434 };
3435 
3436 void PointsToNode::dump(bool print_state) const {
3437   NodeType nt = node_type();
3438   tty->print("%s ", node_type_names[(int) nt]);
3439   if (print_state) {
3440     EscapeState es = escape_state();
3441     EscapeState fields_es = fields_escape_state();
3442     tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
3443     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
3444       tty->print("NSR ");
3445   }
3446   if (is_Field()) {
3447     FieldNode* f = (FieldNode*)this;
3448     if (f->is_oop())
3449       tty->print("oop ");
3450     if (f->offset() > 0)
3451       tty->print("+%d ", f->offset());
3452     tty->print("(");
3453     for (BaseIterator i(f); i.has_next(); i.next()) {
3454       PointsToNode* b = i.get();
3455       tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
3456     }
3457     tty->print(" )");
3458   }
3459   tty->print("[");
3460   for (EdgeIterator i(this); i.has_next(); i.next()) {
3461     PointsToNode* e = i.get();
3462     tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
3463   }
3464   tty->print(" [");
3465   for (UseIterator i(this); i.has_next(); i.next()) {
3466     PointsToNode* u = i.get();
3467     bool is_base = false;
3468     if (PointsToNode::is_base_use(u)) {
3469       is_base = true;
3470       u = PointsToNode::get_use_node(u)->as_Field();
3471     }
3472     tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
3473   }
3474   tty->print(" ]]  ");
3475   if (_node == NULL)
3476     tty->print_cr("<null>");
3477   else
3478     _node->dump();
3479 }
3480 
3481 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
3482   bool first = true;
3483   int ptnodes_length = ptnodes_worklist.length();
3484   for (int i = 0; i < ptnodes_length; i++) {
3485     PointsToNode *ptn = ptnodes_worklist.at(i);
3486     if (ptn == NULL || !ptn->is_JavaObject())
3487       continue;
3488     PointsToNode::EscapeState es = ptn->escape_state();
3489     if ((es != PointsToNode::NoEscape) && !Verbose) {
3490       continue;
3491     }
3492     Node* n = ptn->ideal_node();
3493     if (n->is_Allocate() || (n->is_CallStaticJava() &&
3494                              n->as_CallStaticJava()->is_boxing_method())) {
3495       if (first) {
3496         tty->cr();
3497         tty->print("======== Connection graph for ");
3498         _compile->method()->print_short_name();
3499         tty->cr();
3500         first = false;
3501       }
3502       ptn->dump();
3503       // Print all locals and fields which reference this allocation
3504       for (UseIterator j(ptn); j.has_next(); j.next()) {
3505         PointsToNode* use = j.get();
3506         if (use->is_LocalVar()) {
3507           use->dump(Verbose);
3508         } else if (Verbose) {
3509           use->dump();
3510         }
3511       }
3512       tty->cr();
3513     }
3514   }
3515 }
3516 #endif