1 /*
   2  * Copyright (c) 2005, 2016, 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 "memory/resourceArea.hpp"
  31 #include "opto/c2compiler.hpp"
  32 #include "opto/arraycopynode.hpp"
  33 #include "opto/callnode.hpp"
  34 #include "opto/cfgnode.hpp"
  35 #include "opto/compile.hpp"
  36 #include "opto/escape.hpp"
  37 #include "opto/phaseX.hpp"
  38 #include "opto/movenode.hpp"
  39 #include "opto/rootnode.hpp"
  40 
  41 ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :
  42   _nodes(C->comp_arena(), C->unique(), C->unique(), NULL),
  43   _in_worklist(C->comp_arena()),
  44   _next_pidx(0),
  45   _collecting(true),
  46   _verify(false),
  47   _compile(C),
  48   _igvn(igvn),
  49   _node_map(C->comp_arena()) {
  50   // Add unknown java object.
  51   add_java_object(C->top(), PointsToNode::GlobalEscape);
  52   phantom_obj = ptnode_adr(C->top()->_idx)->as_JavaObject();
  53   // Add ConP(#NULL) and ConN(#NULL) nodes.
  54   Node* oop_null = igvn->zerocon(T_OBJECT);
  55   assert(oop_null->_idx < nodes_size(), "should be created already");
  56   add_java_object(oop_null, PointsToNode::NoEscape);
  57   null_obj = ptnode_adr(oop_null->_idx)->as_JavaObject();
  58   if (UseCompressedOops) {
  59     Node* noop_null = igvn->zerocon(T_NARROWOOP);
  60     assert(noop_null->_idx < nodes_size(), "should be created already");
  61     map_ideal_node(noop_null, null_obj);
  62   }
  63   _pcmp_neq = NULL; // Should be initialized
  64   _pcmp_eq  = NULL;
  65 }
  66 
  67 bool ConnectionGraph::has_candidates(Compile *C) {
  68   // EA brings benefits only when the code has allocations and/or locks which
  69   // are represented by ideal Macro nodes.
  70   int cnt = C->macro_count();
  71   for (int i = 0; i < cnt; i++) {
  72     Node *n = C->macro_node(i);
  73     if (n->is_Allocate())
  74       return true;
  75     if (n->is_Lock()) {
  76       Node* obj = n->as_Lock()->obj_node()->uncast();
  77       if (!(obj->is_Parm() || obj->is_Con()))
  78         return true;
  79     }
  80     if (n->is_CallStaticJava() &&
  81         n->as_CallStaticJava()->is_boxing_method()) {
  82       return true;
  83     }
  84   }
  85   return false;
  86 }
  87 
  88 void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {
  89   Compile::TracePhase tp("escapeAnalysis", &Phase::timers[Phase::_t_escapeAnalysis]);
  90   ResourceMark rm;
  91 
  92   // Add ConP#NULL and ConN#NULL nodes before ConnectionGraph construction
  93   // to create space for them in ConnectionGraph::_nodes[].
  94   Node* oop_null = igvn->zerocon(T_OBJECT);
  95   Node* noop_null = igvn->zerocon(T_NARROWOOP);
  96   ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn);
  97   // Perform escape analysis
  98   if (congraph->compute_escape()) {
  99     // There are non escaping objects.
 100     C->set_congraph(congraph);
 101   }
 102   // Cleanup.
 103   if (oop_null->outcnt() == 0)
 104     igvn->hash_delete(oop_null);
 105   if (noop_null->outcnt() == 0)
 106     igvn->hash_delete(noop_null);
 107 }
 108 
 109 bool ConnectionGraph::compute_escape() {
 110   Compile* C = _compile;
 111   PhaseGVN* igvn = _igvn;
 112 
 113   // Worklists used by EA.
 114   Unique_Node_List delayed_worklist;
 115   GrowableArray<Node*> alloc_worklist;
 116   GrowableArray<Node*> ptr_cmp_worklist;
 117   GrowableArray<Node*> storestore_worklist;
 118   GrowableArray<ArrayCopyNode*> arraycopy_worklist;
 119   GrowableArray<PointsToNode*>   ptnodes_worklist;
 120   GrowableArray<JavaObjectNode*> java_objects_worklist;
 121   GrowableArray<JavaObjectNode*> non_escaped_worklist;
 122   GrowableArray<FieldNode*>      oop_fields_worklist;
 123   DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
 124 
 125   { Compile::TracePhase tp("connectionGraph", &Phase::timers[Phase::_t_connectionGraph]);
 126 
 127   // 1. Populate Connection Graph (CG) with PointsTo nodes.
 128   ideal_nodes.map(C->live_nodes(), NULL);  // preallocate space
 129   // Initialize worklist
 130   if (C->root() != NULL) {
 131     ideal_nodes.push(C->root());
 132   }
 133   // Processed ideal nodes are unique on ideal_nodes list
 134   // but several ideal nodes are mapped to the phantom_obj.
 135   // To avoid duplicated entries on the following worklists
 136   // add the phantom_obj only once to them.
 137   ptnodes_worklist.append(phantom_obj);
 138   java_objects_worklist.append(phantom_obj);
 139   for( uint next = 0; next < ideal_nodes.size(); ++next ) {
 140     Node* n = ideal_nodes.at(next);
 141     // Create PointsTo nodes and add them to Connection Graph. Called
 142     // only once per ideal node since ideal_nodes is Unique_Node list.
 143     add_node_to_connection_graph(n, &delayed_worklist);
 144     PointsToNode* ptn = ptnode_adr(n->_idx);
 145     if (ptn != NULL && ptn != phantom_obj) {
 146       ptnodes_worklist.append(ptn);
 147       if (ptn->is_JavaObject()) {
 148         java_objects_worklist.append(ptn->as_JavaObject());
 149         if ((n->is_Allocate() || n->is_CallStaticJava()) &&
 150             (ptn->escape_state() < PointsToNode::GlobalEscape)) {
 151           // Only allocations and java static calls results are interesting.
 152           non_escaped_worklist.append(ptn->as_JavaObject());
 153         }
 154       } else if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
 155         oop_fields_worklist.append(ptn->as_Field());
 156       }
 157     }
 158     if (n->is_MergeMem()) {
 159       // Collect all MergeMem nodes to add memory slices for
 160       // scalar replaceable objects in split_unique_types().
 161       _mergemem_worklist.append(n->as_MergeMem());
 162     } else if (OptimizePtrCompare && n->is_Cmp() &&
 163                (n->Opcode() == Op_CmpP || n->Opcode() == Op_CmpN)) {
 164       // Collect compare pointers nodes.
 165       ptr_cmp_worklist.append(n);
 166     } else if (n->is_MemBarStoreStore()) {
 167       // Collect all MemBarStoreStore nodes so that depending on the
 168       // escape status of the associated Allocate node some of them
 169       // may be eliminated.
 170       storestore_worklist.append(n);
 171     } else if (n->is_MemBar() && (n->Opcode() == Op_MemBarRelease) &&
 172                (n->req() > MemBarNode::Precedent)) {
 173       record_for_optimizer(n);
 174 #ifdef ASSERT
 175     } else if (n->is_AddP()) {
 176       // Collect address nodes for graph verification.
 177       addp_worklist.append(n);
 178 #endif
 179     } else if (n->is_ArrayCopy()) {
 180       // Keep a list of ArrayCopy nodes so if one of its input is non
 181       // escaping, we can record a unique type
 182       arraycopy_worklist.append(n->as_ArrayCopy());
 183     }
 184     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 185       Node* m = n->fast_out(i);   // Get user
 186       ideal_nodes.push(m);
 187     }
 188   }
 189   if (non_escaped_worklist.length() == 0) {
 190     _collecting = false;
 191     return false; // Nothing to do.
 192   }
 193   // Add final simple edges to graph.
 194   while(delayed_worklist.size() > 0) {
 195     Node* n = delayed_worklist.pop();
 196     add_final_edges(n);
 197   }
 198   int ptnodes_length = ptnodes_worklist.length();
 199 
 200 #ifdef ASSERT
 201   if (VerifyConnectionGraph) {
 202     // Verify that no new simple edges could be created and all
 203     // local vars has edges.
 204     _verify = true;
 205     for (int next = 0; next < ptnodes_length; ++next) {
 206       PointsToNode* ptn = ptnodes_worklist.at(next);
 207       add_final_edges(ptn->ideal_node());
 208       if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
 209         ptn->dump();
 210         assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
 211       }
 212     }
 213     _verify = false;
 214   }
 215 #endif
 216   // Bytecode analyzer BCEscapeAnalyzer, used for Call nodes
 217   // processing, calls to CI to resolve symbols (types, fields, methods)
 218   // referenced in bytecode. During symbol resolution VM may throw
 219   // an exception which CI cleans and converts to compilation failure.
 220   if (C->failing())  return false;
 221 
 222   // 2. Finish Graph construction by propagating references to all
 223   //    java objects through graph.
 224   if (!complete_connection_graph(ptnodes_worklist, non_escaped_worklist,
 225                                  java_objects_worklist, oop_fields_worklist)) {
 226     // All objects escaped or hit time or iterations limits.
 227     _collecting = false;
 228     return false;
 229   }
 230 
 231   // 3. Adjust scalar_replaceable state of nonescaping objects and push
 232   //    scalar replaceable allocations on alloc_worklist for processing
 233   //    in split_unique_types().
 234   int non_escaped_length = non_escaped_worklist.length();
 235   for (int next = 0; next < non_escaped_length; next++) {
 236     JavaObjectNode* ptn = non_escaped_worklist.at(next);
 237     bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
 238     Node* n = ptn->ideal_node();
 239     if (n->is_Allocate()) {
 240       n->as_Allocate()->_is_non_escaping = noescape;
 241     }
 242     if (n->is_CallStaticJava()) {
 243       n->as_CallStaticJava()->_is_non_escaping = noescape;
 244     }
 245     if (noescape && ptn->scalar_replaceable()) {
 246       adjust_scalar_replaceable_state(ptn);
 247       if (ptn->scalar_replaceable()) {
 248         alloc_worklist.append(ptn->ideal_node());
 249       }
 250     }
 251   }
 252 
 253 #ifdef ASSERT
 254   if (VerifyConnectionGraph) {
 255     // Verify that graph is complete - no new edges could be added or needed.
 256     verify_connection_graph(ptnodes_worklist, non_escaped_worklist,
 257                             java_objects_worklist, addp_worklist);
 258   }
 259   assert(C->unique() == nodes_size(), "no new ideal nodes should be added during ConnectionGraph build");
 260   assert(null_obj->escape_state() == PointsToNode::NoEscape &&
 261          null_obj->edge_count() == 0 &&
 262          !null_obj->arraycopy_src() &&
 263          !null_obj->arraycopy_dst(), "sanity");
 264 #endif
 265 
 266   _collecting = false;
 267 
 268   } // TracePhase t3("connectionGraph")
 269 
 270   // 4. Optimize ideal graph based on EA information.
 271   bool has_non_escaping_obj = (non_escaped_worklist.length() > 0);
 272   if (has_non_escaping_obj) {
 273     optimize_ideal_graph(ptr_cmp_worklist, storestore_worklist);
 274   }
 275 
 276 #ifndef PRODUCT
 277   if (PrintEscapeAnalysis) {
 278     dump(ptnodes_worklist); // Dump ConnectionGraph
 279   }
 280 #endif
 281 
 282   bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
 283 #ifdef ASSERT
 284   if (VerifyConnectionGraph) {
 285     int alloc_length = alloc_worklist.length();
 286     for (int next = 0; next < alloc_length; ++next) {
 287       Node* n = alloc_worklist.at(next);
 288       PointsToNode* ptn = ptnode_adr(n->_idx);
 289       assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
 290     }
 291   }
 292 #endif
 293 
 294   // 5. Separate memory graph for scalar replaceable allcations.
 295   if (has_scalar_replaceable_candidates &&
 296       C->AliasLevel() >= 3 && EliminateAllocations) {
 297     // Now use the escape information to create unique types for
 298     // scalar replaceable objects.
 299     split_unique_types(alloc_worklist, arraycopy_worklist);
 300     if (C->failing())  return false;
 301     C->print_method(PHASE_AFTER_EA, 2);
 302 
 303 #ifdef ASSERT
 304   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
 305     tty->print("=== No allocations eliminated for ");
 306     C->method()->print_short_name();
 307     if(!EliminateAllocations) {
 308       tty->print(" since EliminateAllocations is off ===");
 309     } else if(!has_scalar_replaceable_candidates) {
 310       tty->print(" since there are no scalar replaceable candidates ===");
 311     } else if(C->AliasLevel() < 3) {
 312       tty->print(" since AliasLevel < 3 ===");
 313     }
 314     tty->cr();
 315 #endif
 316   }
 317   return has_non_escaping_obj;
 318 }
 319 
 320 // Utility function for nodes that load an object
 321 void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 322   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 323   // ThreadLocal has RawPtr type.
 324   const Type* t = _igvn->type(n);
 325   if (t->make_ptr() != NULL) {
 326     Node* adr = n->in(MemNode::Address);
 327 #ifdef ASSERT
 328     if (!adr->is_AddP()) {
 329       assert(_igvn->type(adr)->isa_rawptr(), "sanity");
 330     } else {
 331       assert((ptnode_adr(adr->_idx) == NULL ||
 332               ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
 333     }
 334 #endif
 335     add_local_var_and_edge(n, PointsToNode::NoEscape,
 336                            adr, delayed_worklist);
 337   }
 338 }
 339 
 340 // Populate Connection Graph with PointsTo nodes and create simple
 341 // connection graph edges.
 342 void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 343   assert(!_verify, "this method should not be called for verification");
 344   PhaseGVN* igvn = _igvn;
 345   uint n_idx = n->_idx;
 346   PointsToNode* n_ptn = ptnode_adr(n_idx);
 347   if (n_ptn != NULL)
 348     return; // No need to redefine PointsTo node during first iteration.
 349 
 350   if (n->is_Call()) {
 351     // Arguments to allocation and locking don't escape.
 352     if (n->is_AbstractLock()) {
 353       // Put Lock and Unlock nodes on IGVN worklist to process them during
 354       // first IGVN optimization when escape information is still available.
 355       record_for_optimizer(n);
 356     } else if (n->is_Allocate()) {
 357       add_call_node(n->as_Call());
 358       record_for_optimizer(n);
 359     } else {
 360       if (n->is_CallStaticJava()) {
 361         const char* name = n->as_CallStaticJava()->_name;
 362         if (name != NULL && strcmp(name, "uncommon_trap") == 0)
 363           return; // Skip uncommon traps
 364       }
 365       // Don't mark as processed since call's arguments have to be processed.
 366       delayed_worklist->push(n);
 367       // Check if a call returns an object.
 368       if ((n->as_Call()->returns_pointer() &&
 369            n->as_Call()->proj_out(TypeFunc::Parms) != NULL) ||
 370           (n->is_CallStaticJava() &&
 371            n->as_CallStaticJava()->is_boxing_method())) {
 372         add_call_node(n->as_Call());
 373       }
 374     }
 375     return;
 376   }
 377   // Put this check here to process call arguments since some call nodes
 378   // point to phantom_obj.
 379   if (n_ptn == phantom_obj || n_ptn == null_obj)
 380     return; // Skip predefined nodes.
 381 
 382   int opcode = n->Opcode();
 383   switch (opcode) {
 384     case Op_AddP: {
 385       Node* base = get_addp_base(n);
 386       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 387       // Field nodes are created for all field types. They are used in
 388       // adjust_scalar_replaceable_state() and split_unique_types().
 389       // Note, non-oop fields will have only base edges in Connection
 390       // Graph because such fields are not used for oop loads and stores.
 391       int offset = address_offset(n, igvn);
 392       add_field(n, PointsToNode::NoEscape, offset);
 393       if (ptn_base == NULL) {
 394         delayed_worklist->push(n); // Process it later.
 395       } else {
 396         n_ptn = ptnode_adr(n_idx);
 397         add_base(n_ptn->as_Field(), ptn_base);
 398       }
 399       break;
 400     }
 401     case Op_CastX2P: {
 402       map_ideal_node(n, phantom_obj);
 403       break;
 404     }
 405     case Op_CastPP:
 406     case Op_CheckCastPP:
 407     case Op_EncodeP:
 408     case Op_DecodeN:
 409     case Op_EncodePKlass:
 410     case Op_DecodeNKlass: {
 411       add_local_var_and_edge(n, PointsToNode::NoEscape,
 412                              n->in(1), delayed_worklist);
 413       break;
 414     }
 415     case Op_CMoveP: {
 416       add_local_var(n, PointsToNode::NoEscape);
 417       // Do not add edges during first iteration because some could be
 418       // not defined yet.
 419       delayed_worklist->push(n);
 420       break;
 421     }
 422     case Op_ConP:
 423     case Op_ConN:
 424     case Op_ConNKlass: {
 425       // assume all oop constants globally escape except for null
 426       PointsToNode::EscapeState es;
 427       const Type* t = igvn->type(n);
 428       if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
 429         es = PointsToNode::NoEscape;
 430       } else {
 431         es = PointsToNode::GlobalEscape;
 432       }
 433       add_java_object(n, es);
 434       break;
 435     }
 436     case Op_CreateEx: {
 437       // assume that all exception objects globally escape
 438       map_ideal_node(n, phantom_obj);
 439       break;
 440     }
 441     case Op_LoadKlass:
 442     case Op_LoadNKlass: {
 443       // Unknown class is loaded
 444       map_ideal_node(n, phantom_obj);
 445       break;
 446     }
 447     case Op_LoadP:
 448     case Op_LoadN:
 449     case Op_LoadPLocked: {
 450       add_objload_to_connection_graph(n, delayed_worklist);
 451       break;
 452     }
 453     case Op_Parm: {
 454       map_ideal_node(n, phantom_obj);
 455       break;
 456     }
 457     case Op_PartialSubtypeCheck: {
 458       // Produces Null or notNull and is used in only in CmpP so
 459       // phantom_obj could be used.
 460       map_ideal_node(n, phantom_obj); // Result is unknown
 461       break;
 462     }
 463     case Op_Phi: {
 464       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 465       // ThreadLocal has RawPtr type.
 466       const Type* t = n->as_Phi()->type();
 467       if (t->make_ptr() != NULL) {
 468         add_local_var(n, PointsToNode::NoEscape);
 469         // Do not add edges during first iteration because some could be
 470         // not defined yet.
 471         delayed_worklist->push(n);
 472       }
 473       break;
 474     }
 475     case Op_Proj: {
 476       // we are only interested in the oop result projection from a call
 477       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 478           n->in(0)->as_Call()->returns_pointer()) {
 479         add_local_var_and_edge(n, PointsToNode::NoEscape,
 480                                n->in(0), delayed_worklist);
 481       }
 482       break;
 483     }
 484     case Op_Rethrow: // Exception object escapes
 485     case Op_Return: {
 486       if (n->req() > TypeFunc::Parms &&
 487           igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 488         // Treat Return value as LocalVar with GlobalEscape escape state.
 489         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 490                                n->in(TypeFunc::Parms), delayed_worklist);
 491       }
 492       break;
 493     }
 494     case Op_CompareAndExchangeP:
 495     case Op_CompareAndExchangeN:
 496     case Op_GetAndSetP:
 497     case Op_GetAndSetN: {
 498       add_objload_to_connection_graph(n, delayed_worklist);
 499       // fallthrough
 500     }
 501     case Op_StoreP:
 502     case Op_StoreN:
 503     case Op_StoreNKlass:
 504     case Op_StorePConditional:
 505     case Op_WeakCompareAndSwapP:
 506     case Op_WeakCompareAndSwapN:
 507     case Op_CompareAndSwapP:
 508     case Op_CompareAndSwapN: {
 509       Node* adr = n->in(MemNode::Address);
 510       const Type *adr_type = igvn->type(adr);
 511       adr_type = adr_type->make_ptr();
 512       if (adr_type == NULL) {
 513         break; // skip dead nodes
 514       }
 515       if (adr_type->isa_oopptr() ||
 516           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
 517                         (adr_type == TypeRawPtr::NOTNULL &&
 518                          adr->in(AddPNode::Address)->is_Proj() &&
 519                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
 520         delayed_worklist->push(n); // Process it later.
 521 #ifdef ASSERT
 522         assert(adr->is_AddP(), "expecting an AddP");
 523         if (adr_type == TypeRawPtr::NOTNULL) {
 524           // Verify a raw address for a store captured by Initialize node.
 525           int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 526           assert(offs != Type::OffsetBot, "offset must be a constant");
 527         }
 528 #endif
 529       } else {
 530         // Ignore copy the displaced header to the BoxNode (OSR compilation).
 531         if (adr->is_BoxLock())
 532           break;
 533         // Stored value escapes in unsafe access.
 534         if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
 535           // Pointer stores in G1 barriers looks like unsafe access.
 536           // Ignore such stores to be able scalar replace non-escaping
 537           // allocations.
 538           if (UseG1GC && adr->is_AddP()) {
 539             Node* base = get_addp_base(adr);
 540             if (base->Opcode() == Op_LoadP &&
 541                 base->in(MemNode::Address)->is_AddP()) {
 542               adr = base->in(MemNode::Address);
 543               Node* tls = get_addp_base(adr);
 544               if (tls->Opcode() == Op_ThreadLocal) {
 545                 int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 546                 if (offs == in_bytes(JavaThread::satb_mark_queue_offset() +
 547                                      SATBMarkQueue::byte_offset_of_buf())) {
 548                   break; // G1 pre barrier previous oop value store.
 549                 }
 550                 if (offs == in_bytes(JavaThread::dirty_card_queue_offset() +
 551                                      DirtyCardQueue::byte_offset_of_buf())) {
 552                   break; // G1 post barrier card address store.
 553                 }
 554               }
 555             }
 556           }
 557           delayed_worklist->push(n); // Process unsafe access later.
 558           break;
 559         }
 560 #ifdef ASSERT
 561         n->dump(1);
 562         assert(false, "not unsafe or G1 barrier raw StoreP");
 563 #endif
 564       }
 565       break;
 566     }
 567     case Op_AryEq:
 568     case Op_HasNegatives:
 569     case Op_StrComp:
 570     case Op_StrEquals:
 571     case Op_StrIndexOf:
 572     case Op_StrIndexOfChar:
 573     case Op_StrInflatedCopy:
 574     case Op_StrCompressedCopy:
 575     case Op_EncodeISOArray: {
 576       add_local_var(n, PointsToNode::ArgEscape);
 577       delayed_worklist->push(n); // Process it later.
 578       break;
 579     }
 580     case Op_ThreadLocal: {
 581       add_java_object(n, PointsToNode::ArgEscape);
 582       break;
 583     }
 584     default:
 585       ; // Do nothing for nodes not related to EA.
 586   }
 587   return;
 588 }
 589 
 590 #ifdef ASSERT
 591 #define ELSE_FAIL(name)                               \
 592       /* Should not be called for not pointer type. */  \
 593       n->dump(1);                                       \
 594       assert(false, name);                              \
 595       break;
 596 #else
 597 #define ELSE_FAIL(name) \
 598       break;
 599 #endif
 600 
 601 // Add final simple edges to graph.
 602 void ConnectionGraph::add_final_edges(Node *n) {
 603   PointsToNode* n_ptn = ptnode_adr(n->_idx);
 604 #ifdef ASSERT
 605   if (_verify && n_ptn->is_JavaObject())
 606     return; // This method does not change graph for JavaObject.
 607 #endif
 608 
 609   if (n->is_Call()) {
 610     process_call_arguments(n->as_Call());
 611     return;
 612   }
 613   assert(n->is_Store() || n->is_LoadStore() ||
 614          (n_ptn != NULL) && (n_ptn->ideal_node() != NULL),
 615          "node should be registered already");
 616   int opcode = n->Opcode();
 617   switch (opcode) {
 618     case Op_AddP: {
 619       Node* base = get_addp_base(n);
 620       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 621       assert(ptn_base != NULL, "field's base should be registered");
 622       add_base(n_ptn->as_Field(), ptn_base);
 623       break;
 624     }
 625     case Op_CastPP:
 626     case Op_CheckCastPP:
 627     case Op_EncodeP:
 628     case Op_DecodeN:
 629     case Op_EncodePKlass:
 630     case Op_DecodeNKlass: {
 631       add_local_var_and_edge(n, PointsToNode::NoEscape,
 632                              n->in(1), NULL);
 633       break;
 634     }
 635     case Op_CMoveP: {
 636       for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
 637         Node* in = n->in(i);
 638         if (in == NULL)
 639           continue;  // ignore NULL
 640         Node* uncast_in = in->uncast();
 641         if (uncast_in->is_top() || uncast_in == n)
 642           continue;  // ignore top or inputs which go back this node
 643         PointsToNode* ptn = ptnode_adr(in->_idx);
 644         assert(ptn != NULL, "node should be registered");
 645         add_edge(n_ptn, ptn);
 646       }
 647       break;
 648     }
 649     case Op_LoadP:
 650     case Op_LoadN:
 651     case Op_LoadPLocked: {
 652       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 653       // ThreadLocal has RawPtr type.
 654       const Type* t = _igvn->type(n);
 655       if (t->make_ptr() != NULL) {
 656         Node* adr = n->in(MemNode::Address);
 657         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 658         break;
 659       }
 660       ELSE_FAIL("Op_LoadP");
 661     }
 662     case Op_Phi: {
 663       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 664       // ThreadLocal has RawPtr type.
 665       const Type* t = n->as_Phi()->type();
 666       if (t->make_ptr() != NULL) {
 667         for (uint i = 1; i < n->req(); i++) {
 668           Node* in = n->in(i);
 669           if (in == NULL)
 670             continue;  // ignore NULL
 671           Node* uncast_in = in->uncast();
 672           if (uncast_in->is_top() || uncast_in == n)
 673             continue;  // ignore top or inputs which go back this node
 674           PointsToNode* ptn = ptnode_adr(in->_idx);
 675           assert(ptn != NULL, "node should be registered");
 676           add_edge(n_ptn, ptn);
 677         }
 678         break;
 679       }
 680       ELSE_FAIL("Op_Phi");
 681     }
 682     case Op_Proj: {
 683       // we are only interested in the oop result projection from a call
 684       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 685           n->in(0)->as_Call()->returns_pointer()) {
 686         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), NULL);
 687         break;
 688       }
 689       ELSE_FAIL("Op_Proj");
 690     }
 691     case Op_Rethrow: // Exception object escapes
 692     case Op_Return: {
 693       if (n->req() > TypeFunc::Parms &&
 694           _igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 695         // Treat Return value as LocalVar with GlobalEscape escape state.
 696         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 697                                n->in(TypeFunc::Parms), NULL);
 698         break;
 699       }
 700       ELSE_FAIL("Op_Return");
 701     }
 702     case Op_StoreP:
 703     case Op_StoreN:
 704     case Op_StoreNKlass:
 705     case Op_StorePConditional:
 706     case Op_CompareAndExchangeP:
 707     case Op_CompareAndExchangeN:
 708     case Op_CompareAndSwapP:
 709     case Op_CompareAndSwapN:
 710     case Op_WeakCompareAndSwapP:
 711     case Op_WeakCompareAndSwapN:
 712     case Op_GetAndSetP:
 713     case Op_GetAndSetN: {
 714       Node* adr = n->in(MemNode::Address);
 715       const Type *adr_type = _igvn->type(adr);
 716       adr_type = adr_type->make_ptr();
 717 #ifdef ASSERT
 718       if (adr_type == NULL) {
 719         n->dump(1);
 720         assert(adr_type != NULL, "dead node should not be on list");
 721         break;
 722       }
 723 #endif
 724       if (opcode == Op_GetAndSetP || opcode == Op_GetAndSetN ||
 725           opcode == Op_CompareAndExchangeN || opcode == Op_CompareAndExchangeP) {
 726         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 727       }
 728       if (adr_type->isa_oopptr() ||
 729           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
 730                         (adr_type == TypeRawPtr::NOTNULL &&
 731                          adr->in(AddPNode::Address)->is_Proj() &&
 732                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
 733         // Point Address to Value
 734         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 735         assert(adr_ptn != NULL &&
 736                adr_ptn->as_Field()->is_oop(), "node should be registered");
 737         Node *val = n->in(MemNode::ValueIn);
 738         PointsToNode* ptn = ptnode_adr(val->_idx);
 739         assert(ptn != NULL, "node should be registered");
 740         add_edge(adr_ptn, ptn);
 741         break;
 742       } else if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
 743         // Stored value escapes in unsafe access.
 744         Node *val = n->in(MemNode::ValueIn);
 745         PointsToNode* ptn = ptnode_adr(val->_idx);
 746         assert(ptn != NULL, "node should be registered");
 747         set_escape_state(ptn, PointsToNode::GlobalEscape);
 748         // Add edge to object for unsafe access with offset.
 749         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 750         assert(adr_ptn != NULL, "node should be registered");
 751         if (adr_ptn->is_Field()) {
 752           assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
 753           add_edge(adr_ptn, ptn);
 754         }
 755         break;
 756       }
 757       ELSE_FAIL("Op_StoreP");
 758     }
 759     case Op_AryEq:
 760     case Op_HasNegatives:
 761     case Op_StrComp:
 762     case Op_StrEquals:
 763     case Op_StrIndexOf:
 764     case Op_StrIndexOfChar:
 765     case Op_StrInflatedCopy:
 766     case Op_StrCompressedCopy:
 767     case Op_EncodeISOArray: {
 768       // char[]/byte[] arrays passed to string intrinsic do not escape but
 769       // they are not scalar replaceable. Adjust escape state for them.
 770       // Start from in(2) edge since in(1) is memory edge.
 771       for (uint i = 2; i < n->req(); i++) {
 772         Node* adr = n->in(i);
 773         const Type* at = _igvn->type(adr);
 774         if (!adr->is_top() && at->isa_ptr()) {
 775           assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
 776                  at->isa_ptr() != NULL, "expecting a pointer");
 777           if (adr->is_AddP()) {
 778             adr = get_addp_base(adr);
 779           }
 780           PointsToNode* ptn = ptnode_adr(adr->_idx);
 781           assert(ptn != NULL, "node should be registered");
 782           add_edge(n_ptn, ptn);
 783         }
 784       }
 785       break;
 786     }
 787     default: {
 788       // This method should be called only for EA specific nodes which may
 789       // miss some edges when they were created.
 790 #ifdef ASSERT
 791       n->dump(1);
 792 #endif
 793       guarantee(false, "unknown node");
 794     }
 795   }
 796   return;
 797 }
 798 
 799 void ConnectionGraph::add_call_node(CallNode* call) {
 800   assert(call->returns_pointer(), "only for call which returns pointer");
 801   uint call_idx = call->_idx;
 802   if (call->is_Allocate()) {
 803     Node* k = call->in(AllocateNode::KlassNode);
 804     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
 805     assert(kt != NULL, "TypeKlassPtr  required.");
 806     ciKlass* cik = kt->klass();
 807     PointsToNode::EscapeState es = PointsToNode::NoEscape;
 808     bool scalar_replaceable = true;
 809     if (call->is_AllocateArray()) {
 810       if (!cik->is_array_klass()) { // StressReflectiveCode
 811         es = PointsToNode::GlobalEscape;
 812       } else {
 813         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
 814         if (length < 0 || length > EliminateAllocationArraySizeLimit) {
 815           // Not scalar replaceable if the length is not constant or too big.
 816           scalar_replaceable = false;
 817         }
 818       }
 819     } else {  // Allocate instance
 820       if (cik->is_subclass_of(_compile->env()->Thread_klass()) ||
 821           cik->is_subclass_of(_compile->env()->Reference_klass()) ||
 822          !cik->is_instance_klass() || // StressReflectiveCode
 823          !cik->as_instance_klass()->can_be_instantiated() ||
 824           cik->as_instance_klass()->has_finalizer()) {
 825         es = PointsToNode::GlobalEscape;
 826       }
 827     }
 828     add_java_object(call, es);
 829     PointsToNode* ptn = ptnode_adr(call_idx);
 830     if (!scalar_replaceable && ptn->scalar_replaceable()) {
 831       ptn->set_scalar_replaceable(false);
 832     }
 833   } else if (call->is_CallStaticJava()) {
 834     // Call nodes could be different types:
 835     //
 836     // 1. CallDynamicJavaNode (what happened during call is unknown):
 837     //
 838     //    - mapped to GlobalEscape JavaObject node if oop is returned;
 839     //
 840     //    - all oop arguments are escaping globally;
 841     //
 842     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
 843     //
 844     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
 845     //
 846     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
 847     //    - mapped to NoEscape JavaObject node if non-escaping object allocated
 848     //      during call is returned;
 849     //    - mapped to ArgEscape LocalVar node pointed to object arguments
 850     //      which are returned and does not escape during call;
 851     //
 852     //    - oop arguments escaping status is defined by bytecode analysis;
 853     //
 854     // For a static call, we know exactly what method is being called.
 855     // Use bytecode estimator to record whether the call's return value escapes.
 856     ciMethod* meth = call->as_CallJava()->method();
 857     if (meth == NULL) {
 858       const char* name = call->as_CallStaticJava()->_name;
 859       assert(strncmp(name, "_multianewarray", 15) == 0, "TODO: add failed case check");
 860       // Returns a newly allocated unescaped object.
 861       add_java_object(call, PointsToNode::NoEscape);
 862       ptnode_adr(call_idx)->set_scalar_replaceable(false);
 863     } else if (meth->is_boxing_method()) {
 864       // Returns boxing object
 865       PointsToNode::EscapeState es;
 866       vmIntrinsics::ID intr = meth->intrinsic_id();
 867       if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
 868         // It does not escape if object is always allocated.
 869         es = PointsToNode::NoEscape;
 870       } else {
 871         // It escapes globally if object could be loaded from cache.
 872         es = PointsToNode::GlobalEscape;
 873       }
 874       add_java_object(call, es);
 875     } else {
 876       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
 877       call_analyzer->copy_dependencies(_compile->dependencies());
 878       if (call_analyzer->is_return_allocated()) {
 879         // Returns a newly allocated unescaped object, simply
 880         // update dependency information.
 881         // Mark it as NoEscape so that objects referenced by
 882         // it's fields will be marked as NoEscape at least.
 883         add_java_object(call, PointsToNode::NoEscape);
 884         ptnode_adr(call_idx)->set_scalar_replaceable(false);
 885       } else {
 886         // Determine whether any arguments are returned.
 887         const TypeTuple* d = call->tf()->domain();
 888         bool ret_arg = false;
 889         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 890           if (d->field_at(i)->isa_ptr() != NULL &&
 891               call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
 892             ret_arg = true;
 893             break;
 894           }
 895         }
 896         if (ret_arg) {
 897           add_local_var(call, PointsToNode::ArgEscape);
 898         } else {
 899           // Returns unknown object.
 900           map_ideal_node(call, phantom_obj);
 901         }
 902       }
 903     }
 904   } else {
 905     // An other type of call, assume the worst case:
 906     // returned value is unknown and globally escapes.
 907     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
 908     map_ideal_node(call, phantom_obj);
 909   }
 910 }
 911 
 912 void ConnectionGraph::process_call_arguments(CallNode *call) {
 913     bool is_arraycopy = false;
 914     switch (call->Opcode()) {
 915 #ifdef ASSERT
 916     case Op_Allocate:
 917     case Op_AllocateArray:
 918     case Op_Lock:
 919     case Op_Unlock:
 920       assert(false, "should be done already");
 921       break;
 922 #endif
 923     case Op_ArrayCopy:
 924     case Op_CallLeafNoFP:
 925       // Most array copies are ArrayCopy nodes at this point but there
 926       // are still a few direct calls to the copy subroutines (See
 927       // PhaseStringOpts::copy_string())
 928       is_arraycopy = (call->Opcode() == Op_ArrayCopy) ||
 929         call->as_CallLeaf()->is_call_to_arraycopystub();
 930       // fall through
 931     case Op_CallLeaf: {
 932       // Stub calls, objects do not escape but they are not scale replaceable.
 933       // Adjust escape state for outgoing arguments.
 934       const TypeTuple * d = call->tf()->domain();
 935       bool src_has_oops = false;
 936       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 937         const Type* at = d->field_at(i);
 938         Node *arg = call->in(i);
 939         if (arg == NULL) {
 940           continue;
 941         }
 942         const Type *aat = _igvn->type(arg);
 943         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr())
 944           continue;
 945         if (arg->is_AddP()) {
 946           //
 947           // The inline_native_clone() case when the arraycopy stub is called
 948           // after the allocation before Initialize and CheckCastPP nodes.
 949           // Or normal arraycopy for object arrays case.
 950           //
 951           // Set AddP's base (Allocate) as not scalar replaceable since
 952           // pointer to the base (with offset) is passed as argument.
 953           //
 954           arg = get_addp_base(arg);
 955         }
 956         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
 957         assert(arg_ptn != NULL, "should be registered");
 958         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
 959         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
 960           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
 961                  aat->isa_ptr() != NULL, "expecting an Ptr");
 962           bool arg_has_oops = aat->isa_oopptr() &&
 963                               (aat->isa_oopptr()->klass() == NULL || aat->isa_instptr() ||
 964                                (aat->isa_aryptr() && aat->isa_aryptr()->klass()->is_obj_array_klass()));
 965           if (i == TypeFunc::Parms) {
 966             src_has_oops = arg_has_oops;
 967           }
 968           //
 969           // src or dst could be j.l.Object when other is basic type array:
 970           //
 971           //   arraycopy(char[],0,Object*,0,size);
 972           //   arraycopy(Object*,0,char[],0,size);
 973           //
 974           // Don't add edges in such cases.
 975           //
 976           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
 977                                        arg_has_oops && (i > TypeFunc::Parms);
 978 #ifdef ASSERT
 979           if (!(is_arraycopy ||
 980                 (call->as_CallLeaf()->_name != NULL &&
 981                  (strcmp(call->as_CallLeaf()->_name, "g1_wb_pre")  == 0 ||
 982                   strcmp(call->as_CallLeaf()->_name, "g1_wb_post") == 0 ||
 983                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
 984                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32C") == 0 ||
 985                   strcmp(call->as_CallLeaf()->_name, "updateBytesAdler32") == 0 ||
 986                   strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
 987                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
 988                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
 989                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
 990                   strcmp(call->as_CallLeaf()->_name, "counterMode_AESCrypt") == 0 ||
 991                   strcmp(call->as_CallLeaf()->_name, "ghash_processBlocks") == 0 ||
 992                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
 993                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
 994                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
 995                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
 996                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
 997                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
 998                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
 999                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
1000                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0 ||
1001                   strcmp(call->as_CallLeaf()->_name, "montgomery_multiply") == 0 ||
1002                   strcmp(call->as_CallLeaf()->_name, "montgomery_square") == 0 ||
1003                   strcmp(call->as_CallLeaf()->_name, "vectorizedMismatch") == 0)
1004                  ))) {
1005             call->dump();
1006             fatal("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name);
1007           }
1008 #endif
1009           // Always process arraycopy's destination object since
1010           // we need to add all possible edges to references in
1011           // source object.
1012           if (arg_esc >= PointsToNode::ArgEscape &&
1013               !arg_is_arraycopy_dest) {
1014             continue;
1015           }
1016           PointsToNode::EscapeState es = PointsToNode::ArgEscape;
1017           if (call->is_ArrayCopy()) {
1018             ArrayCopyNode* ac = call->as_ArrayCopy();
1019             if (ac->is_clonebasic() ||
1020                 ac->is_arraycopy_validated() ||
1021                 ac->is_copyof_validated() ||
1022                 ac->is_copyofrange_validated()) {
1023               es = PointsToNode::NoEscape;
1024             }
1025           }
1026           set_escape_state(arg_ptn, es);
1027           if (arg_is_arraycopy_dest) {
1028             Node* src = call->in(TypeFunc::Parms);
1029             if (src->is_AddP()) {
1030               src = get_addp_base(src);
1031             }
1032             PointsToNode* src_ptn = ptnode_adr(src->_idx);
1033             assert(src_ptn != NULL, "should be registered");
1034             if (arg_ptn != src_ptn) {
1035               // Special arraycopy edge:
1036               // A destination object's field can't have the source object
1037               // as base since objects escape states are not related.
1038               // Only escape state of destination object's fields affects
1039               // escape state of fields in source object.
1040               add_arraycopy(call, es, src_ptn, arg_ptn);
1041             }
1042           }
1043         }
1044       }
1045       break;
1046     }
1047     case Op_CallStaticJava: {
1048       // For a static call, we know exactly what method is being called.
1049       // Use bytecode estimator to record the call's escape affects
1050 #ifdef ASSERT
1051       const char* name = call->as_CallStaticJava()->_name;
1052       assert((name == NULL || strcmp(name, "uncommon_trap") != 0), "normal calls only");
1053 #endif
1054       ciMethod* meth = call->as_CallJava()->method();
1055       if ((meth != NULL) && meth->is_boxing_method()) {
1056         break; // Boxing methods do not modify any oops.
1057       }
1058       BCEscapeAnalyzer* call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
1059       // fall-through if not a Java method or no analyzer information
1060       if (call_analyzer != NULL) {
1061         PointsToNode* call_ptn = ptnode_adr(call->_idx);
1062         const TypeTuple* d = call->tf()->domain();
1063         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1064           const Type* at = d->field_at(i);
1065           int k = i - TypeFunc::Parms;
1066           Node* arg = call->in(i);
1067           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
1068           if (at->isa_ptr() != NULL &&
1069               call_analyzer->is_arg_returned(k)) {
1070             // The call returns arguments.
1071             if (call_ptn != NULL) { // Is call's result used?
1072               assert(call_ptn->is_LocalVar(), "node should be registered");
1073               assert(arg_ptn != NULL, "node should be registered");
1074               add_edge(call_ptn, arg_ptn);
1075             }
1076           }
1077           if (at->isa_oopptr() != NULL &&
1078               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
1079             if (!call_analyzer->is_arg_stack(k)) {
1080               // The argument global escapes
1081               set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1082             } else {
1083               set_escape_state(arg_ptn, PointsToNode::ArgEscape);
1084               if (!call_analyzer->is_arg_local(k)) {
1085                 // The argument itself doesn't escape, but any fields might
1086                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1087               }
1088             }
1089           }
1090         }
1091         if (call_ptn != NULL && call_ptn->is_LocalVar()) {
1092           // The call returns arguments.
1093           assert(call_ptn->edge_count() > 0, "sanity");
1094           if (!call_analyzer->is_return_local()) {
1095             // Returns also unknown object.
1096             add_edge(call_ptn, phantom_obj);
1097           }
1098         }
1099         break;
1100       }
1101     }
1102     default: {
1103       // Fall-through here if not a Java method or no analyzer information
1104       // or some other type of call, assume the worst case: all arguments
1105       // globally escape.
1106       const TypeTuple* d = call->tf()->domain();
1107       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1108         const Type* at = d->field_at(i);
1109         if (at->isa_oopptr() != NULL) {
1110           Node* arg = call->in(i);
1111           if (arg->is_AddP()) {
1112             arg = get_addp_base(arg);
1113           }
1114           assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
1115           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
1116         }
1117       }
1118     }
1119   }
1120 }
1121 
1122 
1123 // Finish Graph construction.
1124 bool ConnectionGraph::complete_connection_graph(
1125                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1126                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1127                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1128                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
1129   // Normally only 1-3 passes needed to build Connection Graph depending
1130   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
1131   // Set limit to 20 to catch situation when something did go wrong and
1132   // bailout Escape Analysis.
1133   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
1134 #define CG_BUILD_ITER_LIMIT 20
1135 
1136   // Propagate GlobalEscape and ArgEscape escape states and check that
1137   // we still have non-escaping objects. The method pushs on _worklist
1138   // Field nodes which reference phantom_object.
1139   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1140     return false; // Nothing to do.
1141   }
1142   // Now propagate references to all JavaObject nodes.
1143   int java_objects_length = java_objects_worklist.length();
1144   elapsedTimer time;
1145   bool timeout = false;
1146   int new_edges = 1;
1147   int iterations = 0;
1148   do {
1149     while ((new_edges > 0) &&
1150            (iterations++ < CG_BUILD_ITER_LIMIT)) {
1151       double start_time = time.seconds();
1152       time.start();
1153       new_edges = 0;
1154       // Propagate references to phantom_object for nodes pushed on _worklist
1155       // by find_non_escaped_objects() and find_field_value().
1156       new_edges += add_java_object_edges(phantom_obj, false);
1157       for (int next = 0; next < java_objects_length; ++next) {
1158         JavaObjectNode* ptn = java_objects_worklist.at(next);
1159         new_edges += add_java_object_edges(ptn, true);
1160 
1161 #define SAMPLE_SIZE 4
1162         if ((next % SAMPLE_SIZE) == 0) {
1163           // Each 4 iterations calculate how much time it will take
1164           // to complete graph construction.
1165           time.stop();
1166           // Poll for requests from shutdown mechanism to quiesce compiler
1167           // because Connection graph construction may take long time.
1168           CompileBroker::maybe_block();
1169           double stop_time = time.seconds();
1170           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
1171           double time_until_end = time_per_iter * (double)(java_objects_length - next);
1172           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
1173             timeout = true;
1174             break; // Timeout
1175           }
1176           start_time = stop_time;
1177           time.start();
1178         }
1179 #undef SAMPLE_SIZE
1180 
1181       }
1182       if (timeout) break;
1183       if (new_edges > 0) {
1184         // Update escape states on each iteration if graph was updated.
1185         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1186           return false; // Nothing to do.
1187         }
1188       }
1189       time.stop();
1190       if (time.seconds() >= EscapeAnalysisTimeout) {
1191         timeout = true;
1192         break;
1193       }
1194     }
1195     if ((iterations < CG_BUILD_ITER_LIMIT) && !timeout) {
1196       time.start();
1197       // Find fields which have unknown value.
1198       int fields_length = oop_fields_worklist.length();
1199       for (int next = 0; next < fields_length; next++) {
1200         FieldNode* field = oop_fields_worklist.at(next);
1201         if (field->edge_count() == 0) {
1202           new_edges += find_field_value(field);
1203           // This code may added new edges to phantom_object.
1204           // Need an other cycle to propagate references to phantom_object.
1205         }
1206       }
1207       time.stop();
1208       if (time.seconds() >= EscapeAnalysisTimeout) {
1209         timeout = true;
1210         break;
1211       }
1212     } else {
1213       new_edges = 0; // Bailout
1214     }
1215   } while (new_edges > 0);
1216 
1217   // Bailout if passed limits.
1218   if ((iterations >= CG_BUILD_ITER_LIMIT) || timeout) {
1219     Compile* C = _compile;
1220     if (C->log() != NULL) {
1221       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
1222       C->log()->text("%s", timeout ? "time" : "iterations");
1223       C->log()->end_elem(" limit'");
1224     }
1225     assert(ExitEscapeAnalysisOnTimeout, "infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
1226            time.seconds(), iterations, nodes_size(), ptnodes_worklist.length());
1227     // Possible infinite build_connection_graph loop,
1228     // bailout (no changes to ideal graph were made).
1229     return false;
1230   }
1231 #ifdef ASSERT
1232   if (Verbose && PrintEscapeAnalysis) {
1233     tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
1234                   iterations, nodes_size(), ptnodes_worklist.length());
1235   }
1236 #endif
1237 
1238 #undef CG_BUILD_ITER_LIMIT
1239 
1240   // Find fields initialized by NULL for non-escaping Allocations.
1241   int non_escaped_length = non_escaped_worklist.length();
1242   for (int next = 0; next < non_escaped_length; next++) {
1243     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1244     PointsToNode::EscapeState es = ptn->escape_state();
1245     assert(es <= PointsToNode::ArgEscape, "sanity");
1246     if (es == PointsToNode::NoEscape) {
1247       if (find_init_values(ptn, null_obj, _igvn) > 0) {
1248         // Adding references to NULL object does not change escape states
1249         // since it does not escape. Also no fields are added to NULL object.
1250         add_java_object_edges(null_obj, false);
1251       }
1252     }
1253     Node* n = ptn->ideal_node();
1254     if (n->is_Allocate()) {
1255       // The object allocated by this Allocate node will never be
1256       // seen by an other thread. Mark it so that when it is
1257       // expanded no MemBarStoreStore is added.
1258       InitializeNode* ini = n->as_Allocate()->initialization();
1259       if (ini != NULL)
1260         ini->set_does_not_escape();
1261     }
1262   }
1263   return true; // Finished graph construction.
1264 }
1265 
1266 // Propagate GlobalEscape and ArgEscape escape states to all nodes
1267 // and check that we still have non-escaping java objects.
1268 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
1269                                                GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
1270   GrowableArray<PointsToNode*> escape_worklist;
1271   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
1272   int ptnodes_length = ptnodes_worklist.length();
1273   for (int next = 0; next < ptnodes_length; ++next) {
1274     PointsToNode* ptn = ptnodes_worklist.at(next);
1275     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
1276         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
1277       escape_worklist.push(ptn);
1278     }
1279   }
1280   // Set escape states to referenced nodes (edges list).
1281   while (escape_worklist.length() > 0) {
1282     PointsToNode* ptn = escape_worklist.pop();
1283     PointsToNode::EscapeState es  = ptn->escape_state();
1284     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
1285     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
1286         es >= PointsToNode::ArgEscape) {
1287       // GlobalEscape or ArgEscape state of field means it has unknown value.
1288       if (add_edge(ptn, phantom_obj)) {
1289         // New edge was added
1290         add_field_uses_to_worklist(ptn->as_Field());
1291       }
1292     }
1293     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1294       PointsToNode* e = i.get();
1295       if (e->is_Arraycopy()) {
1296         assert(ptn->arraycopy_dst(), "sanity");
1297         // Propagate only fields escape state through arraycopy edge.
1298         if (e->fields_escape_state() < field_es) {
1299           set_fields_escape_state(e, field_es);
1300           escape_worklist.push(e);
1301         }
1302       } else if (es >= field_es) {
1303         // fields_escape_state is also set to 'es' if it is less than 'es'.
1304         if (e->escape_state() < es) {
1305           set_escape_state(e, es);
1306           escape_worklist.push(e);
1307         }
1308       } else {
1309         // Propagate field escape state.
1310         bool es_changed = false;
1311         if (e->fields_escape_state() < field_es) {
1312           set_fields_escape_state(e, field_es);
1313           es_changed = true;
1314         }
1315         if ((e->escape_state() < field_es) &&
1316             e->is_Field() && ptn->is_JavaObject() &&
1317             e->as_Field()->is_oop()) {
1318           // Change escape state of referenced fields.
1319           set_escape_state(e, field_es);
1320           es_changed = true;
1321         } else if (e->escape_state() < es) {
1322           set_escape_state(e, es);
1323           es_changed = true;
1324         }
1325         if (es_changed) {
1326           escape_worklist.push(e);
1327         }
1328       }
1329     }
1330   }
1331   // Remove escaped objects from non_escaped list.
1332   for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
1333     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1334     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
1335       non_escaped_worklist.delete_at(next);
1336     }
1337     if (ptn->escape_state() == PointsToNode::NoEscape) {
1338       // Find fields in non-escaped allocations which have unknown value.
1339       find_init_values(ptn, phantom_obj, NULL);
1340     }
1341   }
1342   return (non_escaped_worklist.length() > 0);
1343 }
1344 
1345 // Add all references to JavaObject node by walking over all uses.
1346 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
1347   int new_edges = 0;
1348   if (populate_worklist) {
1349     // Populate _worklist by uses of jobj's uses.
1350     for (UseIterator i(jobj); i.has_next(); i.next()) {
1351       PointsToNode* use = i.get();
1352       if (use->is_Arraycopy())
1353         continue;
1354       add_uses_to_worklist(use);
1355       if (use->is_Field() && use->as_Field()->is_oop()) {
1356         // Put on worklist all field's uses (loads) and
1357         // related field nodes (same base and offset).
1358         add_field_uses_to_worklist(use->as_Field());
1359       }
1360     }
1361   }
1362   for (int l = 0; l < _worklist.length(); l++) {
1363     PointsToNode* use = _worklist.at(l);
1364     if (PointsToNode::is_base_use(use)) {
1365       // Add reference from jobj to field and from field to jobj (field's base).
1366       use = PointsToNode::get_use_node(use)->as_Field();
1367       if (add_base(use->as_Field(), jobj)) {
1368         new_edges++;
1369       }
1370       continue;
1371     }
1372     assert(!use->is_JavaObject(), "sanity");
1373     if (use->is_Arraycopy()) {
1374       if (jobj == null_obj) // NULL object does not have field edges
1375         continue;
1376       // Added edge from Arraycopy node to arraycopy's source java object
1377       if (add_edge(use, jobj)) {
1378         jobj->set_arraycopy_src();
1379         new_edges++;
1380       }
1381       // and stop here.
1382       continue;
1383     }
1384     if (!add_edge(use, jobj))
1385       continue; // No new edge added, there was such edge already.
1386     new_edges++;
1387     if (use->is_LocalVar()) {
1388       add_uses_to_worklist(use);
1389       if (use->arraycopy_dst()) {
1390         for (EdgeIterator i(use); i.has_next(); i.next()) {
1391           PointsToNode* e = i.get();
1392           if (e->is_Arraycopy()) {
1393             if (jobj == null_obj) // NULL object does not have field edges
1394               continue;
1395             // Add edge from arraycopy's destination java object to Arraycopy node.
1396             if (add_edge(jobj, e)) {
1397               new_edges++;
1398               jobj->set_arraycopy_dst();
1399             }
1400           }
1401         }
1402       }
1403     } else {
1404       // Added new edge to stored in field values.
1405       // Put on worklist all field's uses (loads) and
1406       // related field nodes (same base and offset).
1407       add_field_uses_to_worklist(use->as_Field());
1408     }
1409   }
1410   _worklist.clear();
1411   _in_worklist.Reset();
1412   return new_edges;
1413 }
1414 
1415 // Put on worklist all related field nodes.
1416 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
1417   assert(field->is_oop(), "sanity");
1418   int offset = field->offset();
1419   add_uses_to_worklist(field);
1420   // Loop over all bases of this field and push on worklist Field nodes
1421   // with the same offset and base (since they may reference the same field).
1422   for (BaseIterator i(field); i.has_next(); i.next()) {
1423     PointsToNode* base = i.get();
1424     add_fields_to_worklist(field, base);
1425     // Check if the base was source object of arraycopy and go over arraycopy's
1426     // destination objects since values stored to a field of source object are
1427     // accessable by uses (loads) of fields of destination objects.
1428     if (base->arraycopy_src()) {
1429       for (UseIterator j(base); j.has_next(); j.next()) {
1430         PointsToNode* arycp = j.get();
1431         if (arycp->is_Arraycopy()) {
1432           for (UseIterator k(arycp); k.has_next(); k.next()) {
1433             PointsToNode* abase = k.get();
1434             if (abase->arraycopy_dst() && abase != base) {
1435               // Look for the same arraycopy reference.
1436               add_fields_to_worklist(field, abase);
1437             }
1438           }
1439         }
1440       }
1441     }
1442   }
1443 }
1444 
1445 // Put on worklist all related field nodes.
1446 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
1447   int offset = field->offset();
1448   if (base->is_LocalVar()) {
1449     for (UseIterator j(base); j.has_next(); j.next()) {
1450       PointsToNode* f = j.get();
1451       if (PointsToNode::is_base_use(f)) { // Field
1452         f = PointsToNode::get_use_node(f);
1453         if (f == field || !f->as_Field()->is_oop())
1454           continue;
1455         int offs = f->as_Field()->offset();
1456         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1457           add_to_worklist(f);
1458         }
1459       }
1460     }
1461   } else {
1462     assert(base->is_JavaObject(), "sanity");
1463     if (// Skip phantom_object since it is only used to indicate that
1464         // this field's content globally escapes.
1465         (base != phantom_obj) &&
1466         // NULL object node does not have fields.
1467         (base != null_obj)) {
1468       for (EdgeIterator i(base); i.has_next(); i.next()) {
1469         PointsToNode* f = i.get();
1470         // Skip arraycopy edge since store to destination object field
1471         // does not update value in source object field.
1472         if (f->is_Arraycopy()) {
1473           assert(base->arraycopy_dst(), "sanity");
1474           continue;
1475         }
1476         if (f == field || !f->as_Field()->is_oop())
1477           continue;
1478         int offs = f->as_Field()->offset();
1479         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1480           add_to_worklist(f);
1481         }
1482       }
1483     }
1484   }
1485 }
1486 
1487 // Find fields which have unknown value.
1488 int ConnectionGraph::find_field_value(FieldNode* field) {
1489   // Escaped fields should have init value already.
1490   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
1491   int new_edges = 0;
1492   for (BaseIterator i(field); i.has_next(); i.next()) {
1493     PointsToNode* base = i.get();
1494     if (base->is_JavaObject()) {
1495       // Skip Allocate's fields which will be processed later.
1496       if (base->ideal_node()->is_Allocate())
1497         return 0;
1498       assert(base == null_obj, "only NULL ptr base expected here");
1499     }
1500   }
1501   if (add_edge(field, phantom_obj)) {
1502     // New edge was added
1503     new_edges++;
1504     add_field_uses_to_worklist(field);
1505   }
1506   return new_edges;
1507 }
1508 
1509 // Find fields initializing values for allocations.
1510 int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
1511   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
1512   int new_edges = 0;
1513   Node* alloc = pta->ideal_node();
1514   if (init_val == phantom_obj) {
1515     // Do nothing for Allocate nodes since its fields values are
1516     // "known" unless they are initialized by arraycopy/clone.
1517     if (alloc->is_Allocate() && !pta->arraycopy_dst())
1518       return 0;
1519     assert(pta->arraycopy_dst() || alloc->as_CallStaticJava(), "sanity");
1520 #ifdef ASSERT
1521     if (!pta->arraycopy_dst() && alloc->as_CallStaticJava()->method() == NULL) {
1522       const char* name = alloc->as_CallStaticJava()->_name;
1523       assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
1524     }
1525 #endif
1526     // Non-escaped allocation returned from Java or runtime call have
1527     // unknown values in fields.
1528     for (EdgeIterator i(pta); i.has_next(); i.next()) {
1529       PointsToNode* field = i.get();
1530       if (field->is_Field() && field->as_Field()->is_oop()) {
1531         if (add_edge(field, phantom_obj)) {
1532           // New edge was added
1533           new_edges++;
1534           add_field_uses_to_worklist(field->as_Field());
1535         }
1536       }
1537     }
1538     return new_edges;
1539   }
1540   assert(init_val == null_obj, "sanity");
1541   // Do nothing for Call nodes since its fields values are unknown.
1542   if (!alloc->is_Allocate())
1543     return 0;
1544 
1545   InitializeNode* ini = alloc->as_Allocate()->initialization();
1546   bool visited_bottom_offset = false;
1547   GrowableArray<int> offsets_worklist;
1548 
1549   // Check if an oop field's initializing value is recorded and add
1550   // a corresponding NULL if field's value if it is not recorded.
1551   // Connection Graph does not record a default initialization by NULL
1552   // captured by Initialize node.
1553   //
1554   for (EdgeIterator i(pta); i.has_next(); i.next()) {
1555     PointsToNode* field = i.get(); // Field (AddP)
1556     if (!field->is_Field() || !field->as_Field()->is_oop())
1557       continue; // Not oop field
1558     int offset = field->as_Field()->offset();
1559     if (offset == Type::OffsetBot) {
1560       if (!visited_bottom_offset) {
1561         // OffsetBot is used to reference array's element,
1562         // always add reference to NULL to all Field nodes since we don't
1563         // known which element is referenced.
1564         if (add_edge(field, null_obj)) {
1565           // New edge was added
1566           new_edges++;
1567           add_field_uses_to_worklist(field->as_Field());
1568           visited_bottom_offset = true;
1569         }
1570       }
1571     } else {
1572       // Check only oop fields.
1573       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
1574       if (adr_type->isa_rawptr()) {
1575 #ifdef ASSERT
1576         // Raw pointers are used for initializing stores so skip it
1577         // since it should be recorded already
1578         Node* base = get_addp_base(field->ideal_node());
1579         assert(adr_type->isa_rawptr() && base->is_Proj() &&
1580                (base->in(0) == alloc),"unexpected pointer type");
1581 #endif
1582         continue;
1583       }
1584       if (!offsets_worklist.contains(offset)) {
1585         offsets_worklist.append(offset);
1586         Node* value = NULL;
1587         if (ini != NULL) {
1588           // StoreP::memory_type() == T_ADDRESS
1589           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
1590           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
1591           // Make sure initializing store has the same type as this AddP.
1592           // This AddP may reference non existing field because it is on a
1593           // dead branch of bimorphic call which is not eliminated yet.
1594           if (store != NULL && store->is_Store() &&
1595               store->as_Store()->memory_type() == ft) {
1596             value = store->in(MemNode::ValueIn);
1597 #ifdef ASSERT
1598             if (VerifyConnectionGraph) {
1599               // Verify that AddP already points to all objects the value points to.
1600               PointsToNode* val = ptnode_adr(value->_idx);
1601               assert((val != NULL), "should be processed already");
1602               PointsToNode* missed_obj = NULL;
1603               if (val->is_JavaObject()) {
1604                 if (!field->points_to(val->as_JavaObject())) {
1605                   missed_obj = val;
1606                 }
1607               } else {
1608                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
1609                   tty->print_cr("----------init store has invalid value -----");
1610                   store->dump();
1611                   val->dump();
1612                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
1613                 }
1614                 for (EdgeIterator j(val); j.has_next(); j.next()) {
1615                   PointsToNode* obj = j.get();
1616                   if (obj->is_JavaObject()) {
1617                     if (!field->points_to(obj->as_JavaObject())) {
1618                       missed_obj = obj;
1619                       break;
1620                     }
1621                   }
1622                 }
1623               }
1624               if (missed_obj != NULL) {
1625                 tty->print_cr("----------field---------------------------------");
1626                 field->dump();
1627                 tty->print_cr("----------missed referernce to object-----------");
1628                 missed_obj->dump();
1629                 tty->print_cr("----------object referernced by init store -----");
1630                 store->dump();
1631                 val->dump();
1632                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
1633               }
1634             }
1635 #endif
1636           } else {
1637             // There could be initializing stores which follow allocation.
1638             // For example, a volatile field store is not collected
1639             // by Initialize node.
1640             //
1641             // Need to check for dependent loads to separate such stores from
1642             // stores which follow loads. For now, add initial value NULL so
1643             // that compare pointers optimization works correctly.
1644           }
1645         }
1646         if (value == NULL) {
1647           // A field's initializing value was not recorded. Add NULL.
1648           if (add_edge(field, null_obj)) {
1649             // New edge was added
1650             new_edges++;
1651             add_field_uses_to_worklist(field->as_Field());
1652           }
1653         }
1654       }
1655     }
1656   }
1657   return new_edges;
1658 }
1659 
1660 // Adjust scalar_replaceable state after Connection Graph is built.
1661 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
1662   // Search for non-escaping objects which are not scalar replaceable
1663   // and mark them to propagate the state to referenced objects.
1664 
1665   // 1. An object is not scalar replaceable if the field into which it is
1666   // stored has unknown offset (stored into unknown element of an array).
1667   //
1668   for (UseIterator i(jobj); i.has_next(); i.next()) {
1669     PointsToNode* use = i.get();
1670     if (use->is_Arraycopy()) {
1671       continue;
1672     }
1673     if (use->is_Field()) {
1674       FieldNode* field = use->as_Field();
1675       assert(field->is_oop() && field->scalar_replaceable(), "sanity");
1676       if (field->offset() == Type::OffsetBot) {
1677         jobj->set_scalar_replaceable(false);
1678         return;
1679       }
1680       // 2. An object is not scalar replaceable if the field into which it is
1681       // stored has multiple bases one of which is null.
1682       if (field->base_count() > 1) {
1683         for (BaseIterator i(field); i.has_next(); i.next()) {
1684           PointsToNode* base = i.get();
1685           if (base == null_obj) {
1686             jobj->set_scalar_replaceable(false);
1687             return;
1688           }
1689         }
1690       }
1691     }
1692     assert(use->is_Field() || use->is_LocalVar(), "sanity");
1693     // 3. An object is not scalar replaceable if it is merged with other objects.
1694     for (EdgeIterator j(use); j.has_next(); j.next()) {
1695       PointsToNode* ptn = j.get();
1696       if (ptn->is_JavaObject() && ptn != jobj) {
1697         // Mark all objects.
1698         jobj->set_scalar_replaceable(false);
1699          ptn->set_scalar_replaceable(false);
1700       }
1701     }
1702     if (!jobj->scalar_replaceable()) {
1703       return;
1704     }
1705   }
1706 
1707   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
1708     if (j.get()->is_Arraycopy()) {
1709       continue;
1710     }
1711 
1712     // Non-escaping object node should point only to field nodes.
1713     FieldNode* field = j.get()->as_Field();
1714     int offset = field->as_Field()->offset();
1715 
1716     // 4. An object is not scalar replaceable if it has a field with unknown
1717     // offset (array's element is accessed in loop).
1718     if (offset == Type::OffsetBot) {
1719       jobj->set_scalar_replaceable(false);
1720       return;
1721     }
1722     // 5. Currently an object is not scalar replaceable if a LoadStore node
1723     // access its field since the field value is unknown after it.
1724     //
1725     Node* n = field->ideal_node();
1726     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1727       if (n->fast_out(i)->is_LoadStore()) {
1728         jobj->set_scalar_replaceable(false);
1729         return;
1730       }
1731     }
1732 
1733     // 6. Or the address may point to more then one object. This may produce
1734     // the false positive result (set not scalar replaceable)
1735     // since the flow-insensitive escape analysis can't separate
1736     // the case when stores overwrite the field's value from the case
1737     // when stores happened on different control branches.
1738     //
1739     // Note: it will disable scalar replacement in some cases:
1740     //
1741     //    Point p[] = new Point[1];
1742     //    p[0] = new Point(); // Will be not scalar replaced
1743     //
1744     // but it will save us from incorrect optimizations in next cases:
1745     //
1746     //    Point p[] = new Point[1];
1747     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
1748     //
1749     if (field->base_count() > 1) {
1750       for (BaseIterator i(field); i.has_next(); i.next()) {
1751         PointsToNode* base = i.get();
1752         // Don't take into account LocalVar nodes which
1753         // may point to only one object which should be also
1754         // this field's base by now.
1755         if (base->is_JavaObject() && base != jobj) {
1756           // Mark all bases.
1757           jobj->set_scalar_replaceable(false);
1758           base->set_scalar_replaceable(false);
1759         }
1760       }
1761     }
1762   }
1763 }
1764 
1765 #ifdef ASSERT
1766 void ConnectionGraph::verify_connection_graph(
1767                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1768                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1769                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1770                          GrowableArray<Node*>& addp_worklist) {
1771   // Verify that graph is complete - no new edges could be added.
1772   int java_objects_length = java_objects_worklist.length();
1773   int non_escaped_length  = non_escaped_worklist.length();
1774   int new_edges = 0;
1775   for (int next = 0; next < java_objects_length; ++next) {
1776     JavaObjectNode* ptn = java_objects_worklist.at(next);
1777     new_edges += add_java_object_edges(ptn, true);
1778   }
1779   assert(new_edges == 0, "graph was not complete");
1780   // Verify that escape state is final.
1781   int length = non_escaped_worklist.length();
1782   find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
1783   assert((non_escaped_length == non_escaped_worklist.length()) &&
1784          (non_escaped_length == length) &&
1785          (_worklist.length() == 0), "escape state was not final");
1786 
1787   // Verify fields information.
1788   int addp_length = addp_worklist.length();
1789   for (int next = 0; next < addp_length; ++next ) {
1790     Node* n = addp_worklist.at(next);
1791     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
1792     if (field->is_oop()) {
1793       // Verify that field has all bases
1794       Node* base = get_addp_base(n);
1795       PointsToNode* ptn = ptnode_adr(base->_idx);
1796       if (ptn->is_JavaObject()) {
1797         assert(field->has_base(ptn->as_JavaObject()), "sanity");
1798       } else {
1799         assert(ptn->is_LocalVar(), "sanity");
1800         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1801           PointsToNode* e = i.get();
1802           if (e->is_JavaObject()) {
1803             assert(field->has_base(e->as_JavaObject()), "sanity");
1804           }
1805         }
1806       }
1807       // Verify that all fields have initializing values.
1808       if (field->edge_count() == 0) {
1809         tty->print_cr("----------field does not have references----------");
1810         field->dump();
1811         for (BaseIterator i(field); i.has_next(); i.next()) {
1812           PointsToNode* base = i.get();
1813           tty->print_cr("----------field has next base---------------------");
1814           base->dump();
1815           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
1816             tty->print_cr("----------base has fields-------------------------");
1817             for (EdgeIterator j(base); j.has_next(); j.next()) {
1818               j.get()->dump();
1819             }
1820             tty->print_cr("----------base has references---------------------");
1821             for (UseIterator j(base); j.has_next(); j.next()) {
1822               j.get()->dump();
1823             }
1824           }
1825         }
1826         for (UseIterator i(field); i.has_next(); i.next()) {
1827           i.get()->dump();
1828         }
1829         assert(field->edge_count() > 0, "sanity");
1830       }
1831     }
1832   }
1833 }
1834 #endif
1835 
1836 // Optimize ideal graph.
1837 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
1838                                            GrowableArray<Node*>& storestore_worklist) {
1839   Compile* C = _compile;
1840   PhaseIterGVN* igvn = _igvn;
1841   if (EliminateLocks) {
1842     // Mark locks before changing ideal graph.
1843     int cnt = C->macro_count();
1844     for( int i=0; i < cnt; i++ ) {
1845       Node *n = C->macro_node(i);
1846       if (n->is_AbstractLock()) { // Lock and Unlock nodes
1847         AbstractLockNode* alock = n->as_AbstractLock();
1848         if (!alock->is_non_esc_obj()) {
1849           if (not_global_escape(alock->obj_node())) {
1850             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
1851             // The lock could be marked eliminated by lock coarsening
1852             // code during first IGVN before EA. Replace coarsened flag
1853             // to eliminate all associated locks/unlocks.
1854 #ifdef ASSERT
1855             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
1856 #endif
1857             alock->set_non_esc_obj();
1858           }
1859         }
1860       }
1861     }
1862   }
1863 
1864   if (OptimizePtrCompare) {
1865     // Add ConI(#CC_GT) and ConI(#CC_EQ).
1866     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);
1867     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
1868     // Optimize objects compare.
1869     while (ptr_cmp_worklist.length() != 0) {
1870       Node *n = ptr_cmp_worklist.pop();
1871       Node *res = optimize_ptr_compare(n);
1872       if (res != NULL) {
1873 #ifndef PRODUCT
1874         if (PrintOptimizePtrCompare) {
1875           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"));
1876           if (Verbose) {
1877             n->dump(1);
1878           }
1879         }
1880 #endif
1881         igvn->replace_node(n, res);
1882       }
1883     }
1884     // cleanup
1885     if (_pcmp_neq->outcnt() == 0)
1886       igvn->hash_delete(_pcmp_neq);
1887     if (_pcmp_eq->outcnt()  == 0)
1888       igvn->hash_delete(_pcmp_eq);
1889   }
1890 
1891   // For MemBarStoreStore nodes added in library_call.cpp, check
1892   // escape status of associated AllocateNode and optimize out
1893   // MemBarStoreStore node if the allocated object never escapes.
1894   while (storestore_worklist.length() != 0) {
1895     Node *n = storestore_worklist.pop();
1896     MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
1897     Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
1898     assert (alloc->is_Allocate(), "storestore should point to AllocateNode");
1899     if (not_global_escape(alloc)) {
1900       MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
1901       mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
1902       mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
1903       igvn->register_new_node_with_optimizer(mb);
1904       igvn->replace_node(storestore, mb);
1905     }
1906   }
1907 }
1908 
1909 // Optimize objects compare.
1910 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
1911   assert(OptimizePtrCompare, "sanity");
1912   PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
1913   PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
1914   JavaObjectNode* jobj1 = unique_java_object(n->in(1));
1915   JavaObjectNode* jobj2 = unique_java_object(n->in(2));
1916   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
1917   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
1918 
1919   // Check simple cases first.
1920   if (jobj1 != NULL) {
1921     if (jobj1->escape_state() == PointsToNode::NoEscape) {
1922       if (jobj1 == jobj2) {
1923         // Comparing the same not escaping object.
1924         return _pcmp_eq;
1925       }
1926       Node* obj = jobj1->ideal_node();
1927       // Comparing not escaping allocation.
1928       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1929           !ptn2->points_to(jobj1)) {
1930         return _pcmp_neq; // This includes nullness check.
1931       }
1932     }
1933   }
1934   if (jobj2 != NULL) {
1935     if (jobj2->escape_state() == PointsToNode::NoEscape) {
1936       Node* obj = jobj2->ideal_node();
1937       // Comparing not escaping allocation.
1938       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1939           !ptn1->points_to(jobj2)) {
1940         return _pcmp_neq; // This includes nullness check.
1941       }
1942     }
1943   }
1944   if (jobj1 != NULL && jobj1 != phantom_obj &&
1945       jobj2 != NULL && jobj2 != phantom_obj &&
1946       jobj1->ideal_node()->is_Con() &&
1947       jobj2->ideal_node()->is_Con()) {
1948     // Klass or String constants compare. Need to be careful with
1949     // compressed pointers - compare types of ConN and ConP instead of nodes.
1950     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
1951     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
1952     if (t1->make_ptr() == t2->make_ptr()) {
1953       return _pcmp_eq;
1954     } else {
1955       return _pcmp_neq;
1956     }
1957   }
1958   if (ptn1->meet(ptn2)) {
1959     return NULL; // Sets are not disjoint
1960   }
1961 
1962   // Sets are disjoint.
1963   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
1964   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
1965   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
1966   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
1967   if (set1_has_unknown_ptr && set2_has_null_ptr ||
1968       set2_has_unknown_ptr && set1_has_null_ptr) {
1969     // Check nullness of unknown object.
1970     return NULL;
1971   }
1972 
1973   // Disjointness by itself is not sufficient since
1974   // alias analysis is not complete for escaped objects.
1975   // Disjoint sets are definitely unrelated only when
1976   // at least one set has only not escaping allocations.
1977   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
1978     if (ptn1->non_escaping_allocation()) {
1979       return _pcmp_neq;
1980     }
1981   }
1982   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
1983     if (ptn2->non_escaping_allocation()) {
1984       return _pcmp_neq;
1985     }
1986   }
1987   return NULL;
1988 }
1989 
1990 // Connection Graph constuction functions.
1991 
1992 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
1993   PointsToNode* ptadr = _nodes.at(n->_idx);
1994   if (ptadr != NULL) {
1995     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
1996     return;
1997   }
1998   Compile* C = _compile;
1999   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
2000   _nodes.at_put(n->_idx, ptadr);
2001 }
2002 
2003 void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
2004   PointsToNode* ptadr = _nodes.at(n->_idx);
2005   if (ptadr != NULL) {
2006     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
2007     return;
2008   }
2009   Compile* C = _compile;
2010   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
2011   _nodes.at_put(n->_idx, ptadr);
2012 }
2013 
2014 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
2015   PointsToNode* ptadr = _nodes.at(n->_idx);
2016   if (ptadr != NULL) {
2017     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
2018     return;
2019   }
2020   bool unsafe = false;
2021   bool is_oop = is_oop_field(n, offset, &unsafe);
2022   if (unsafe) {
2023     es = PointsToNode::GlobalEscape;
2024   }
2025   Compile* C = _compile;
2026   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
2027   _nodes.at_put(n->_idx, field);
2028 }
2029 
2030 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
2031                                     PointsToNode* src, PointsToNode* dst) {
2032   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
2033   assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
2034   PointsToNode* ptadr = _nodes.at(n->_idx);
2035   if (ptadr != NULL) {
2036     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
2037     return;
2038   }
2039   Compile* C = _compile;
2040   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
2041   _nodes.at_put(n->_idx, ptadr);
2042   // Add edge from arraycopy node to source object.
2043   (void)add_edge(ptadr, src);
2044   src->set_arraycopy_src();
2045   // Add edge from destination object to arraycopy node.
2046   (void)add_edge(dst, ptadr);
2047   dst->set_arraycopy_dst();
2048 }
2049 
2050 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
2051   const Type* adr_type = n->as_AddP()->bottom_type();
2052   BasicType bt = T_INT;
2053   if (offset == Type::OffsetBot) {
2054     // Check only oop fields.
2055     if (!adr_type->isa_aryptr() ||
2056         (adr_type->isa_aryptr()->klass() == NULL) ||
2057          adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
2058       // OffsetBot is used to reference array's element. Ignore first AddP.
2059       if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
2060         bt = T_OBJECT;
2061       }
2062     }
2063   } else if (offset != oopDesc::klass_offset_in_bytes()) {
2064     if (adr_type->isa_instptr()) {
2065       ciField* field = _compile->alias_type(adr_type->isa_instptr())->field();
2066       if (field != NULL) {
2067         bt = field->layout_type();
2068       } else {
2069         // Check for unsafe oop field access
2070         if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
2071           bt = T_OBJECT;
2072           (*unsafe) = true;
2073         }
2074       }
2075     } else if (adr_type->isa_aryptr()) {
2076       if (offset == arrayOopDesc::length_offset_in_bytes()) {
2077         // Ignore array length load.
2078       } else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
2079         // Ignore first AddP.
2080       } else {
2081         const Type* elemtype = adr_type->isa_aryptr()->elem();
2082         bt = elemtype->array_element_basic_type();
2083       }
2084     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
2085       // Allocation initialization, ThreadLocal field access, unsafe access
2086       if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
2087         bt = T_OBJECT;
2088       }
2089     }
2090   }
2091   return (bt == T_OBJECT || bt == T_NARROWOOP || bt == T_ARRAY);
2092 }
2093 
2094 // Returns unique pointed java object or NULL.
2095 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
2096   assert(!_collecting, "should not call when contructed graph");
2097   // If the node was created after the escape computation we can't answer.
2098   uint idx = n->_idx;
2099   if (idx >= nodes_size()) {
2100     return NULL;
2101   }
2102   PointsToNode* ptn = ptnode_adr(idx);
2103   if (ptn->is_JavaObject()) {
2104     return ptn->as_JavaObject();
2105   }
2106   assert(ptn->is_LocalVar(), "sanity");
2107   // Check all java objects it points to.
2108   JavaObjectNode* jobj = NULL;
2109   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2110     PointsToNode* e = i.get();
2111     if (e->is_JavaObject()) {
2112       if (jobj == NULL) {
2113         jobj = e->as_JavaObject();
2114       } else if (jobj != e) {
2115         return NULL;
2116       }
2117     }
2118   }
2119   return jobj;
2120 }
2121 
2122 // Return true if this node points only to non-escaping allocations.
2123 bool PointsToNode::non_escaping_allocation() {
2124   if (is_JavaObject()) {
2125     Node* n = ideal_node();
2126     if (n->is_Allocate() || n->is_CallStaticJava()) {
2127       return (escape_state() == PointsToNode::NoEscape);
2128     } else {
2129       return false;
2130     }
2131   }
2132   assert(is_LocalVar(), "sanity");
2133   // Check all java objects it points to.
2134   for (EdgeIterator i(this); i.has_next(); i.next()) {
2135     PointsToNode* e = i.get();
2136     if (e->is_JavaObject()) {
2137       Node* n = e->ideal_node();
2138       if ((e->escape_state() != PointsToNode::NoEscape) ||
2139           !(n->is_Allocate() || n->is_CallStaticJava())) {
2140         return false;
2141       }
2142     }
2143   }
2144   return true;
2145 }
2146 
2147 // Return true if we know the node does not escape globally.
2148 bool ConnectionGraph::not_global_escape(Node *n) {
2149   assert(!_collecting, "should not call during graph construction");
2150   // If the node was created after the escape computation we can't answer.
2151   uint idx = n->_idx;
2152   if (idx >= nodes_size()) {
2153     return false;
2154   }
2155   PointsToNode* ptn = ptnode_adr(idx);
2156   PointsToNode::EscapeState es = ptn->escape_state();
2157   // If we have already computed a value, return it.
2158   if (es >= PointsToNode::GlobalEscape)
2159     return false;
2160   if (ptn->is_JavaObject()) {
2161     return true; // (es < PointsToNode::GlobalEscape);
2162   }
2163   assert(ptn->is_LocalVar(), "sanity");
2164   // Check all java objects it points to.
2165   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2166     if (i.get()->escape_state() >= PointsToNode::GlobalEscape)
2167       return false;
2168   }
2169   return true;
2170 }
2171 
2172 
2173 // Helper functions
2174 
2175 // Return true if this node points to specified node or nodes it points to.
2176 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
2177   if (is_JavaObject()) {
2178     return (this == ptn);
2179   }
2180   assert(is_LocalVar() || is_Field(), "sanity");
2181   for (EdgeIterator i(this); i.has_next(); i.next()) {
2182     if (i.get() == ptn)
2183       return true;
2184   }
2185   return false;
2186 }
2187 
2188 // Return true if one node points to an other.
2189 bool PointsToNode::meet(PointsToNode* ptn) {
2190   if (this == ptn) {
2191     return true;
2192   } else if (ptn->is_JavaObject()) {
2193     return this->points_to(ptn->as_JavaObject());
2194   } else if (this->is_JavaObject()) {
2195     return ptn->points_to(this->as_JavaObject());
2196   }
2197   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
2198   int ptn_count =  ptn->edge_count();
2199   for (EdgeIterator i(this); i.has_next(); i.next()) {
2200     PointsToNode* this_e = i.get();
2201     for (int j = 0; j < ptn_count; j++) {
2202       if (this_e == ptn->edge(j))
2203         return true;
2204     }
2205   }
2206   return false;
2207 }
2208 
2209 #ifdef ASSERT
2210 // Return true if bases point to this java object.
2211 bool FieldNode::has_base(JavaObjectNode* jobj) const {
2212   for (BaseIterator i(this); i.has_next(); i.next()) {
2213     if (i.get() == jobj)
2214       return true;
2215   }
2216   return false;
2217 }
2218 #endif
2219 
2220 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
2221   const Type *adr_type = phase->type(adr);
2222   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
2223       adr->in(AddPNode::Address)->is_Proj() &&
2224       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
2225     // We are computing a raw address for a store captured by an Initialize
2226     // compute an appropriate address type. AddP cases #3 and #5 (see below).
2227     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
2228     assert(offs != Type::OffsetBot ||
2229            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
2230            "offset must be a constant or it is initialization of array");
2231     return offs;
2232   }
2233   const TypePtr *t_ptr = adr_type->isa_ptr();
2234   assert(t_ptr != NULL, "must be a pointer type");
2235   return t_ptr->offset();
2236 }
2237 
2238 Node* ConnectionGraph::get_addp_base(Node *addp) {
2239   assert(addp->is_AddP(), "must be AddP");
2240   //
2241   // AddP cases for Base and Address inputs:
2242   // case #1. Direct object's field reference:
2243   //     Allocate
2244   //       |
2245   //     Proj #5 ( oop result )
2246   //       |
2247   //     CheckCastPP (cast to instance type)
2248   //      | |
2249   //     AddP  ( base == address )
2250   //
2251   // case #2. Indirect object's field reference:
2252   //      Phi
2253   //       |
2254   //     CastPP (cast to instance type)
2255   //      | |
2256   //     AddP  ( base == address )
2257   //
2258   // case #3. Raw object's field reference for Initialize node:
2259   //      Allocate
2260   //        |
2261   //      Proj #5 ( oop result )
2262   //  top   |
2263   //     \  |
2264   //     AddP  ( base == top )
2265   //
2266   // case #4. Array's element reference:
2267   //   {CheckCastPP | CastPP}
2268   //     |  | |
2269   //     |  AddP ( array's element offset )
2270   //     |  |
2271   //     AddP ( array's offset )
2272   //
2273   // case #5. Raw object's field reference for arraycopy stub call:
2274   //          The inline_native_clone() case when the arraycopy stub is called
2275   //          after the allocation before Initialize and CheckCastPP nodes.
2276   //      Allocate
2277   //        |
2278   //      Proj #5 ( oop result )
2279   //       | |
2280   //       AddP  ( base == address )
2281   //
2282   // case #6. Constant Pool, ThreadLocal, CastX2P or
2283   //          Raw object's field reference:
2284   //      {ConP, ThreadLocal, CastX2P, raw Load}
2285   //  top   |
2286   //     \  |
2287   //     AddP  ( base == top )
2288   //
2289   // case #7. Klass's field reference.
2290   //      LoadKlass
2291   //       | |
2292   //       AddP  ( base == address )
2293   //
2294   // case #8. narrow Klass's field reference.
2295   //      LoadNKlass
2296   //       |
2297   //      DecodeN
2298   //       | |
2299   //       AddP  ( base == address )
2300   //
2301   Node *base = addp->in(AddPNode::Base);
2302   if (base->uncast()->is_top()) { // The AddP case #3 and #6.
2303     base = addp->in(AddPNode::Address);
2304     while (base->is_AddP()) {
2305       // Case #6 (unsafe access) may have several chained AddP nodes.
2306       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
2307       base = base->in(AddPNode::Address);
2308     }
2309     Node* uncast_base = base->uncast();
2310     int opcode = uncast_base->Opcode();
2311     assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
2312            opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
2313            (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
2314            (uncast_base->is_Proj() && uncast_base->in(0)->is_Allocate()), "sanity");
2315   }
2316   return base;
2317 }
2318 
2319 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
2320   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
2321   Node* addp2 = addp->raw_out(0);
2322   if (addp->outcnt() == 1 && addp2->is_AddP() &&
2323       addp2->in(AddPNode::Base) == n &&
2324       addp2->in(AddPNode::Address) == addp) {
2325     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
2326     //
2327     // Find array's offset to push it on worklist first and
2328     // as result process an array's element offset first (pushed second)
2329     // to avoid CastPP for the array's offset.
2330     // Otherwise the inserted CastPP (LocalVar) will point to what
2331     // the AddP (Field) points to. Which would be wrong since
2332     // the algorithm expects the CastPP has the same point as
2333     // as AddP's base CheckCastPP (LocalVar).
2334     //
2335     //    ArrayAllocation
2336     //     |
2337     //    CheckCastPP
2338     //     |
2339     //    memProj (from ArrayAllocation CheckCastPP)
2340     //     |  ||
2341     //     |  ||   Int (element index)
2342     //     |  ||    |   ConI (log(element size))
2343     //     |  ||    |   /
2344     //     |  ||   LShift
2345     //     |  ||  /
2346     //     |  AddP (array's element offset)
2347     //     |  |
2348     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
2349     //     | / /
2350     //     AddP (array's offset)
2351     //      |
2352     //     Load/Store (memory operation on array's element)
2353     //
2354     return addp2;
2355   }
2356   return NULL;
2357 }
2358 
2359 //
2360 // Adjust the type and inputs of an AddP which computes the
2361 // address of a field of an instance
2362 //
2363 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
2364   PhaseGVN* igvn = _igvn;
2365   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
2366   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
2367   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
2368   if (t == NULL) {
2369     // We are computing a raw address for a store captured by an Initialize
2370     // compute an appropriate address type (cases #3 and #5).
2371     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
2372     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
2373     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
2374     assert(offs != Type::OffsetBot, "offset must be a constant");
2375     t = base_t->add_offset(offs)->is_oopptr();
2376   }
2377   int inst_id =  base_t->instance_id();
2378   assert(!t->is_known_instance() || t->instance_id() == inst_id,
2379                              "old type must be non-instance or match new type");
2380 
2381   // The type 't' could be subclass of 'base_t'.
2382   // As result t->offset() could be large then base_t's size and it will
2383   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
2384   // constructor verifies correctness of the offset.
2385   //
2386   // It could happened on subclass's branch (from the type profiling
2387   // inlining) which was not eliminated during parsing since the exactness
2388   // of the allocation type was not propagated to the subclass type check.
2389   //
2390   // Or the type 't' could be not related to 'base_t' at all.
2391   // It could happened when CHA type is different from MDO type on a dead path
2392   // (for example, from instanceof check) which is not collapsed during parsing.
2393   //
2394   // Do nothing for such AddP node and don't process its users since
2395   // this code branch will go away.
2396   //
2397   if (!t->is_known_instance() &&
2398       !base_t->klass()->is_subtype_of(t->klass())) {
2399      return false; // bail out
2400   }
2401   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
2402   // Do NOT remove the next line: ensure a new alias index is allocated
2403   // for the instance type. Note: C++ will not remove it since the call
2404   // has side effect.
2405   int alias_idx = _compile->get_alias_index(tinst);
2406   igvn->set_type(addp, tinst);
2407   // record the allocation in the node map
2408   set_map(addp, get_map(base->_idx));
2409   // Set addp's Base and Address to 'base'.
2410   Node *abase = addp->in(AddPNode::Base);
2411   Node *adr   = addp->in(AddPNode::Address);
2412   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
2413       adr->in(0)->_idx == (uint)inst_id) {
2414     // Skip AddP cases #3 and #5.
2415   } else {
2416     assert(!abase->is_top(), "sanity"); // AddP case #3
2417     if (abase != base) {
2418       igvn->hash_delete(addp);
2419       addp->set_req(AddPNode::Base, base);
2420       if (abase == adr) {
2421         addp->set_req(AddPNode::Address, base);
2422       } else {
2423         // AddP case #4 (adr is array's element offset AddP node)
2424 #ifdef ASSERT
2425         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
2426         assert(adr->is_AddP() && atype != NULL &&
2427                atype->instance_id() == inst_id, "array's element offset should be processed first");
2428 #endif
2429       }
2430       igvn->hash_insert(addp);
2431     }
2432   }
2433   // Put on IGVN worklist since at least addp's type was changed above.
2434   record_for_optimizer(addp);
2435   return true;
2436 }
2437 
2438 //
2439 // Create a new version of orig_phi if necessary. Returns either the newly
2440 // created phi or an existing phi.  Sets create_new to indicate whether a new
2441 // phi was created.  Cache the last newly created phi in the node map.
2442 //
2443 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
2444   Compile *C = _compile;
2445   PhaseGVN* igvn = _igvn;
2446   new_created = false;
2447   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
2448   // nothing to do if orig_phi is bottom memory or matches alias_idx
2449   if (phi_alias_idx == alias_idx) {
2450     return orig_phi;
2451   }
2452   // Have we recently created a Phi for this alias index?
2453   PhiNode *result = get_map_phi(orig_phi->_idx);
2454   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
2455     return result;
2456   }
2457   // Previous check may fail when the same wide memory Phi was split into Phis
2458   // for different memory slices. Search all Phis for this region.
2459   if (result != NULL) {
2460     Node* region = orig_phi->in(0);
2461     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
2462       Node* phi = region->fast_out(i);
2463       if (phi->is_Phi() &&
2464           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
2465         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
2466         return phi->as_Phi();
2467       }
2468     }
2469   }
2470   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
2471     if (C->do_escape_analysis() == true && !C->failing()) {
2472       // Retry compilation without escape analysis.
2473       // If this is the first failure, the sentinel string will "stick"
2474       // to the Compile object, and the C2Compiler will see it and retry.
2475       C->record_failure(C2Compiler::retry_no_escape_analysis());
2476     }
2477     return NULL;
2478   }
2479   orig_phi_worklist.append_if_missing(orig_phi);
2480   const TypePtr *atype = C->get_adr_type(alias_idx);
2481   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
2482   C->copy_node_notes_to(result, orig_phi);
2483   igvn->set_type(result, result->bottom_type());
2484   record_for_optimizer(result);
2485   set_map(orig_phi, result);
2486   new_created = true;
2487   return result;
2488 }
2489 
2490 //
2491 // Return a new version of Memory Phi "orig_phi" with the inputs having the
2492 // specified alias index.
2493 //
2494 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist) {
2495   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
2496   Compile *C = _compile;
2497   PhaseGVN* igvn = _igvn;
2498   bool new_phi_created;
2499   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
2500   if (!new_phi_created) {
2501     return result;
2502   }
2503   GrowableArray<PhiNode *>  phi_list;
2504   GrowableArray<uint>  cur_input;
2505   PhiNode *phi = orig_phi;
2506   uint idx = 1;
2507   bool finished = false;
2508   while(!finished) {
2509     while (idx < phi->req()) {
2510       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist);
2511       if (mem != NULL && mem->is_Phi()) {
2512         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
2513         if (new_phi_created) {
2514           // found an phi for which we created a new split, push current one on worklist and begin
2515           // processing new one
2516           phi_list.push(phi);
2517           cur_input.push(idx);
2518           phi = mem->as_Phi();
2519           result = newphi;
2520           idx = 1;
2521           continue;
2522         } else {
2523           mem = newphi;
2524         }
2525       }
2526       if (C->failing()) {
2527         return NULL;
2528       }
2529       result->set_req(idx++, mem);
2530     }
2531 #ifdef ASSERT
2532     // verify that the new Phi has an input for each input of the original
2533     assert( phi->req() == result->req(), "must have same number of inputs.");
2534     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
2535 #endif
2536     // Check if all new phi's inputs have specified alias index.
2537     // Otherwise use old phi.
2538     for (uint i = 1; i < phi->req(); i++) {
2539       Node* in = result->in(i);
2540       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
2541     }
2542     // we have finished processing a Phi, see if there are any more to do
2543     finished = (phi_list.length() == 0 );
2544     if (!finished) {
2545       phi = phi_list.pop();
2546       idx = cur_input.pop();
2547       PhiNode *prev_result = get_map_phi(phi->_idx);
2548       prev_result->set_req(idx++, result);
2549       result = prev_result;
2550     }
2551   }
2552   return result;
2553 }
2554 
2555 //
2556 // The next methods are derived from methods in MemNode.
2557 //
2558 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
2559   Node *mem = mmem;
2560   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
2561   // means an array I have not precisely typed yet.  Do not do any
2562   // alias stuff with it any time soon.
2563   if (toop->base() != Type::AnyPtr &&
2564       !(toop->klass() != NULL &&
2565         toop->klass()->is_java_lang_Object() &&
2566         toop->offset() == Type::OffsetBot)) {
2567     mem = mmem->memory_at(alias_idx);
2568     // Update input if it is progress over what we have now
2569   }
2570   return mem;
2571 }
2572 
2573 //
2574 // Move memory users to their memory slices.
2575 //
2576 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
2577   Compile* C = _compile;
2578   PhaseGVN* igvn = _igvn;
2579   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
2580   assert(tp != NULL, "ptr type");
2581   int alias_idx = C->get_alias_index(tp);
2582   int general_idx = C->get_general_index(alias_idx);
2583 
2584   // Move users first
2585   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2586     Node* use = n->fast_out(i);
2587     if (use->is_MergeMem()) {
2588       MergeMemNode* mmem = use->as_MergeMem();
2589       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
2590       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
2591         continue; // Nothing to do
2592       }
2593       // Replace previous general reference to mem node.
2594       uint orig_uniq = C->unique();
2595       Node* m = find_inst_mem(n, general_idx, orig_phis);
2596       assert(orig_uniq == C->unique(), "no new nodes");
2597       mmem->set_memory_at(general_idx, m);
2598       --imax;
2599       --i;
2600     } else if (use->is_MemBar()) {
2601       assert(!use->is_Initialize(), "initializing stores should not be moved");
2602       if (use->req() > MemBarNode::Precedent &&
2603           use->in(MemBarNode::Precedent) == n) {
2604         // Don't move related membars.
2605         record_for_optimizer(use);
2606         continue;
2607       }
2608       tp = use->as_MemBar()->adr_type()->isa_ptr();
2609       if (tp != NULL && C->get_alias_index(tp) == alias_idx ||
2610           alias_idx == general_idx) {
2611         continue; // Nothing to do
2612       }
2613       // Move to general memory slice.
2614       uint orig_uniq = C->unique();
2615       Node* m = find_inst_mem(n, general_idx, orig_phis);
2616       assert(orig_uniq == C->unique(), "no new nodes");
2617       igvn->hash_delete(use);
2618       imax -= use->replace_edge(n, m);
2619       igvn->hash_insert(use);
2620       record_for_optimizer(use);
2621       --i;
2622 #ifdef ASSERT
2623     } else if (use->is_Mem()) {
2624       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
2625         // Don't move related cardmark.
2626         continue;
2627       }
2628       // Memory nodes should have new memory input.
2629       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
2630       assert(tp != NULL, "ptr type");
2631       int idx = C->get_alias_index(tp);
2632       assert(get_map(use->_idx) != NULL || idx == alias_idx,
2633              "Following memory nodes should have new memory input or be on the same memory slice");
2634     } else if (use->is_Phi()) {
2635       // Phi nodes should be split and moved already.
2636       tp = use->as_Phi()->adr_type()->isa_ptr();
2637       assert(tp != NULL, "ptr type");
2638       int idx = C->get_alias_index(tp);
2639       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
2640     } else {
2641       use->dump();
2642       assert(false, "should not be here");
2643 #endif
2644     }
2645   }
2646 }
2647 
2648 //
2649 // Search memory chain of "mem" to find a MemNode whose address
2650 // is the specified alias index.
2651 //
2652 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis) {
2653   if (orig_mem == NULL)
2654     return orig_mem;
2655   Compile* C = _compile;
2656   PhaseGVN* igvn = _igvn;
2657   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
2658   bool is_instance = (toop != NULL) && toop->is_known_instance();
2659   Node *start_mem = C->start()->proj_out(TypeFunc::Memory);
2660   Node *prev = NULL;
2661   Node *result = orig_mem;
2662   while (prev != result) {
2663     prev = result;
2664     if (result == start_mem)
2665       break;  // hit one of our sentinels
2666     if (result->is_Mem()) {
2667       const Type *at = igvn->type(result->in(MemNode::Address));
2668       if (at == Type::TOP)
2669         break; // Dead
2670       assert (at->isa_ptr() != NULL, "pointer type required.");
2671       int idx = C->get_alias_index(at->is_ptr());
2672       if (idx == alias_idx)
2673         break; // Found
2674       if (!is_instance && (at->isa_oopptr() == NULL ||
2675                            !at->is_oopptr()->is_known_instance())) {
2676         break; // Do not skip store to general memory slice.
2677       }
2678       result = result->in(MemNode::Memory);
2679     }
2680     if (!is_instance)
2681       continue;  // don't search further for non-instance types
2682     // skip over a call which does not affect this memory slice
2683     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
2684       Node *proj_in = result->in(0);
2685       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
2686         break;  // hit one of our sentinels
2687       } else if (proj_in->is_Call()) {
2688         // ArrayCopy node processed here as well
2689         CallNode *call = proj_in->as_Call();
2690         if (!call->may_modify(toop, igvn)) {
2691           result = call->in(TypeFunc::Memory);
2692         }
2693       } else if (proj_in->is_Initialize()) {
2694         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
2695         // Stop if this is the initialization for the object instance which
2696         // which contains this memory slice, otherwise skip over it.
2697         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
2698           result = proj_in->in(TypeFunc::Memory);
2699         }
2700       } else if (proj_in->is_MemBar()) {
2701         if (proj_in->in(TypeFunc::Memory)->is_MergeMem() &&
2702             proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->is_Proj() &&
2703             proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->is_ArrayCopy()) {
2704           // clone
2705           ArrayCopyNode* ac = proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->as_ArrayCopy();
2706           if (ac->may_modify(toop, igvn)) {
2707             break;
2708           }
2709         }
2710         result = proj_in->in(TypeFunc::Memory);
2711       }
2712     } else if (result->is_MergeMem()) {
2713       MergeMemNode *mmem = result->as_MergeMem();
2714       result = step_through_mergemem(mmem, alias_idx, toop);
2715       if (result == mmem->base_memory()) {
2716         // Didn't find instance memory, search through general slice recursively.
2717         result = mmem->memory_at(C->get_general_index(alias_idx));
2718         result = find_inst_mem(result, alias_idx, orig_phis);
2719         if (C->failing()) {
2720           return NULL;
2721         }
2722         mmem->set_memory_at(alias_idx, result);
2723       }
2724     } else if (result->is_Phi() &&
2725                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
2726       Node *un = result->as_Phi()->unique_input(igvn);
2727       if (un != NULL) {
2728         orig_phis.append_if_missing(result->as_Phi());
2729         result = un;
2730       } else {
2731         break;
2732       }
2733     } else if (result->is_ClearArray()) {
2734       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
2735         // Can not bypass initialization of the instance
2736         // we are looking for.
2737         break;
2738       }
2739       // Otherwise skip it (the call updated 'result' value).
2740     } else if (result->Opcode() == Op_SCMemProj) {
2741       Node* mem = result->in(0);
2742       Node* adr = NULL;
2743       if (mem->is_LoadStore()) {
2744         adr = mem->in(MemNode::Address);
2745       } else {
2746         assert(mem->Opcode() == Op_EncodeISOArray ||
2747                mem->Opcode() == Op_StrCompressedCopy, "sanity");
2748         adr = mem->in(3); // Memory edge corresponds to destination array
2749       }
2750       const Type *at = igvn->type(adr);
2751       if (at != Type::TOP) {
2752         assert(at->isa_ptr() != NULL, "pointer type required.");
2753         int idx = C->get_alias_index(at->is_ptr());
2754         if (idx == alias_idx) {
2755           // Assert in debug mode
2756           assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
2757           break; // In product mode return SCMemProj node
2758         }
2759       }
2760       result = mem->in(MemNode::Memory);
2761     } else if (result->Opcode() == Op_StrInflatedCopy) {
2762       Node* adr = result->in(3); // Memory edge corresponds to destination array
2763       const Type *at = igvn->type(adr);
2764       if (at != Type::TOP) {
2765         assert(at->isa_ptr() != NULL, "pointer type required.");
2766         int idx = C->get_alias_index(at->is_ptr());
2767         if (idx == alias_idx) {
2768           // Assert in debug mode
2769           assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
2770           break; // In product mode return SCMemProj node
2771         }
2772       }
2773       result = result->in(MemNode::Memory);
2774     }
2775   }
2776   if (result->is_Phi()) {
2777     PhiNode *mphi = result->as_Phi();
2778     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
2779     const TypePtr *t = mphi->adr_type();
2780     if (!is_instance) {
2781       // Push all non-instance Phis on the orig_phis worklist to update inputs
2782       // during Phase 4 if needed.
2783       orig_phis.append_if_missing(mphi);
2784     } else if (C->get_alias_index(t) != alias_idx) {
2785       // Create a new Phi with the specified alias index type.
2786       result = split_memory_phi(mphi, alias_idx, orig_phis);
2787     }
2788   }
2789   // the result is either MemNode, PhiNode, InitializeNode.
2790   return result;
2791 }
2792 
2793 //
2794 //  Convert the types of unescaped object to instance types where possible,
2795 //  propagate the new type information through the graph, and update memory
2796 //  edges and MergeMem inputs to reflect the new type.
2797 //
2798 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
2799 //  The processing is done in 4 phases:
2800 //
2801 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
2802 //            types for the CheckCastPP for allocations where possible.
2803 //            Propagate the new types through users as follows:
2804 //               casts and Phi:  push users on alloc_worklist
2805 //               AddP:  cast Base and Address inputs to the instance type
2806 //                      push any AddP users on alloc_worklist and push any memnode
2807 //                      users onto memnode_worklist.
2808 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
2809 //            search the Memory chain for a store with the appropriate type
2810 //            address type.  If a Phi is found, create a new version with
2811 //            the appropriate memory slices from each of the Phi inputs.
2812 //            For stores, process the users as follows:
2813 //               MemNode:  push on memnode_worklist
2814 //               MergeMem: push on mergemem_worklist
2815 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
2816 //            moving the first node encountered of each  instance type to the
2817 //            the input corresponding to its alias index.
2818 //            appropriate memory slice.
2819 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
2820 //
2821 // In the following example, the CheckCastPP nodes are the cast of allocation
2822 // results and the allocation of node 29 is unescaped and eligible to be an
2823 // instance type.
2824 //
2825 // We start with:
2826 //
2827 //     7 Parm #memory
2828 //    10  ConI  "12"
2829 //    19  CheckCastPP   "Foo"
2830 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2831 //    29  CheckCastPP   "Foo"
2832 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
2833 //
2834 //    40  StoreP  25   7  20   ... alias_index=4
2835 //    50  StoreP  35  40  30   ... alias_index=4
2836 //    60  StoreP  45  50  20   ... alias_index=4
2837 //    70  LoadP    _  60  30   ... alias_index=4
2838 //    80  Phi     75  50  60   Memory alias_index=4
2839 //    90  LoadP    _  80  30   ... alias_index=4
2840 //   100  LoadP    _  80  20   ... alias_index=4
2841 //
2842 //
2843 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
2844 // and creating a new alias index for node 30.  This gives:
2845 //
2846 //     7 Parm #memory
2847 //    10  ConI  "12"
2848 //    19  CheckCastPP   "Foo"
2849 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2850 //    29  CheckCastPP   "Foo"  iid=24
2851 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2852 //
2853 //    40  StoreP  25   7  20   ... alias_index=4
2854 //    50  StoreP  35  40  30   ... alias_index=6
2855 //    60  StoreP  45  50  20   ... alias_index=4
2856 //    70  LoadP    _  60  30   ... alias_index=6
2857 //    80  Phi     75  50  60   Memory alias_index=4
2858 //    90  LoadP    _  80  30   ... alias_index=6
2859 //   100  LoadP    _  80  20   ... alias_index=4
2860 //
2861 // In phase 2, new memory inputs are computed for the loads and stores,
2862 // And a new version of the phi is created.  In phase 4, the inputs to
2863 // node 80 are updated and then the memory nodes are updated with the
2864 // values computed in phase 2.  This results in:
2865 //
2866 //     7 Parm #memory
2867 //    10  ConI  "12"
2868 //    19  CheckCastPP   "Foo"
2869 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2870 //    29  CheckCastPP   "Foo"  iid=24
2871 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2872 //
2873 //    40  StoreP  25  7   20   ... alias_index=4
2874 //    50  StoreP  35  7   30   ... alias_index=6
2875 //    60  StoreP  45  40  20   ... alias_index=4
2876 //    70  LoadP    _  50  30   ... alias_index=6
2877 //    80  Phi     75  40  60   Memory alias_index=4
2878 //   120  Phi     75  50  50   Memory alias_index=6
2879 //    90  LoadP    _ 120  30   ... alias_index=6
2880 //   100  LoadP    _  80  20   ... alias_index=4
2881 //
2882 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist, GrowableArray<ArrayCopyNode*> &arraycopy_worklist) {
2883   GrowableArray<Node *>  memnode_worklist;
2884   GrowableArray<PhiNode *>  orig_phis;
2885   PhaseIterGVN  *igvn = _igvn;
2886   uint new_index_start = (uint) _compile->num_alias_types();
2887   Arena* arena = Thread::current()->resource_area();
2888   VectorSet visited(arena);
2889   ideal_nodes.clear(); // Reset for use with set_map/get_map.
2890   uint unique_old = _compile->unique();
2891 
2892   //  Phase 1:  Process possible allocations from alloc_worklist.
2893   //  Create instance types for the CheckCastPP for allocations where possible.
2894   //
2895   // (Note: don't forget to change the order of the second AddP node on
2896   //  the alloc_worklist if the order of the worklist processing is changed,
2897   //  see the comment in find_second_addp().)
2898   //
2899   while (alloc_worklist.length() != 0) {
2900     Node *n = alloc_worklist.pop();
2901     uint ni = n->_idx;
2902     if (n->is_Call()) {
2903       CallNode *alloc = n->as_Call();
2904       // copy escape information to call node
2905       PointsToNode* ptn = ptnode_adr(alloc->_idx);
2906       PointsToNode::EscapeState es = ptn->escape_state();
2907       // We have an allocation or call which returns a Java object,
2908       // see if it is unescaped.
2909       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
2910         continue;
2911       // Find CheckCastPP for the allocate or for the return value of a call
2912       n = alloc->result_cast();
2913       if (n == NULL) {            // No uses except Initialize node
2914         if (alloc->is_Allocate()) {
2915           // Set the scalar_replaceable flag for allocation
2916           // so it could be eliminated if it has no uses.
2917           alloc->as_Allocate()->_is_scalar_replaceable = true;
2918         }
2919         if (alloc->is_CallStaticJava()) {
2920           // Set the scalar_replaceable flag for boxing method
2921           // so it could be eliminated if it has no uses.
2922           alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2923         }
2924         continue;
2925       }
2926       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
2927         assert(!alloc->is_Allocate(), "allocation should have unique type");
2928         continue;
2929       }
2930 
2931       // The inline code for Object.clone() casts the allocation result to
2932       // java.lang.Object and then to the actual type of the allocated
2933       // object. Detect this case and use the second cast.
2934       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
2935       // the allocation result is cast to java.lang.Object and then
2936       // to the actual Array type.
2937       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
2938           && (alloc->is_AllocateArray() ||
2939               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
2940         Node *cast2 = NULL;
2941         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2942           Node *use = n->fast_out(i);
2943           if (use->is_CheckCastPP()) {
2944             cast2 = use;
2945             break;
2946           }
2947         }
2948         if (cast2 != NULL) {
2949           n = cast2;
2950         } else {
2951           // Non-scalar replaceable if the allocation type is unknown statically
2952           // (reflection allocation), the object can't be restored during
2953           // deoptimization without precise type.
2954           continue;
2955         }
2956       }
2957 
2958       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
2959       if (t == NULL)
2960         continue;  // not a TypeOopPtr
2961       if (!t->klass_is_exact())
2962         continue; // not an unique type
2963 
2964       if (alloc->is_Allocate()) {
2965         // Set the scalar_replaceable flag for allocation
2966         // so it could be eliminated.
2967         alloc->as_Allocate()->_is_scalar_replaceable = true;
2968       }
2969       if (alloc->is_CallStaticJava()) {
2970         // Set the scalar_replaceable flag for boxing method
2971         // so it could be eliminated.
2972         alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2973       }
2974       set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
2975       // in order for an object to be scalar-replaceable, it must be:
2976       //   - a direct allocation (not a call returning an object)
2977       //   - non-escaping
2978       //   - eligible to be a unique type
2979       //   - not determined to be ineligible by escape analysis
2980       set_map(alloc, n);
2981       set_map(n, alloc);
2982       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
2983       igvn->hash_delete(n);
2984       igvn->set_type(n,  tinst);
2985       n->raise_bottom_type(tinst);
2986       igvn->hash_insert(n);
2987       record_for_optimizer(n);
2988       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
2989 
2990         // First, put on the worklist all Field edges from Connection Graph
2991         // which is more accurate than putting immediate users from Ideal Graph.
2992         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
2993           PointsToNode* tgt = e.get();
2994           if (tgt->is_Arraycopy()) {
2995             continue;
2996           }
2997           Node* use = tgt->ideal_node();
2998           assert(tgt->is_Field() && use->is_AddP(),
2999                  "only AddP nodes are Field edges in CG");
3000           if (use->outcnt() > 0) { // Don't process dead nodes
3001             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
3002             if (addp2 != NULL) {
3003               assert(alloc->is_AllocateArray(),"array allocation was expected");
3004               alloc_worklist.append_if_missing(addp2);
3005             }
3006             alloc_worklist.append_if_missing(use);
3007           }
3008         }
3009 
3010         // An allocation may have an Initialize which has raw stores. Scan
3011         // the users of the raw allocation result and push AddP users
3012         // on alloc_worklist.
3013         Node *raw_result = alloc->proj_out(TypeFunc::Parms);
3014         assert (raw_result != NULL, "must have an allocation result");
3015         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
3016           Node *use = raw_result->fast_out(i);
3017           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
3018             Node* addp2 = find_second_addp(use, raw_result);
3019             if (addp2 != NULL) {
3020               assert(alloc->is_AllocateArray(),"array allocation was expected");
3021               alloc_worklist.append_if_missing(addp2);
3022             }
3023             alloc_worklist.append_if_missing(use);
3024           } else if (use->is_MemBar()) {
3025             memnode_worklist.append_if_missing(use);
3026           }
3027         }
3028       }
3029     } else if (n->is_AddP()) {
3030       JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
3031       if (jobj == NULL || jobj == phantom_obj) {
3032 #ifdef ASSERT
3033         ptnode_adr(get_addp_base(n)->_idx)->dump();
3034         ptnode_adr(n->_idx)->dump();
3035         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3036 #endif
3037         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3038         return;
3039       }
3040       Node *base = get_map(jobj->idx());  // CheckCastPP node
3041       if (!split_AddP(n, base)) continue; // wrong type from dead path
3042     } else if (n->is_Phi() ||
3043                n->is_CheckCastPP() ||
3044                n->is_EncodeP() ||
3045                n->is_DecodeN() ||
3046                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
3047       if (visited.test_set(n->_idx)) {
3048         assert(n->is_Phi(), "loops only through Phi's");
3049         continue;  // already processed
3050       }
3051       JavaObjectNode* jobj = unique_java_object(n);
3052       if (jobj == NULL || jobj == phantom_obj) {
3053 #ifdef ASSERT
3054         ptnode_adr(n->_idx)->dump();
3055         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3056 #endif
3057         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3058         return;
3059       } else {
3060         Node *val = get_map(jobj->idx());   // CheckCastPP node
3061         TypeNode *tn = n->as_Type();
3062         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
3063         assert(tinst != NULL && tinst->is_known_instance() &&
3064                tinst->instance_id() == jobj->idx() , "instance type expected.");
3065 
3066         const Type *tn_type = igvn->type(tn);
3067         const TypeOopPtr *tn_t;
3068         if (tn_type->isa_narrowoop()) {
3069           tn_t = tn_type->make_ptr()->isa_oopptr();
3070         } else {
3071           tn_t = tn_type->isa_oopptr();
3072         }
3073         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
3074           if (tn_type->isa_narrowoop()) {
3075             tn_type = tinst->make_narrowoop();
3076           } else {
3077             tn_type = tinst;
3078           }
3079           igvn->hash_delete(tn);
3080           igvn->set_type(tn, tn_type);
3081           tn->set_type(tn_type);
3082           igvn->hash_insert(tn);
3083           record_for_optimizer(n);
3084         } else {
3085           assert(tn_type == TypePtr::NULL_PTR ||
3086                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
3087                  "unexpected type");
3088           continue; // Skip dead path with different type
3089         }
3090       }
3091     } else {
3092       debug_only(n->dump();)
3093       assert(false, "EA: unexpected node");
3094       continue;
3095     }
3096     // push allocation's users on appropriate worklist
3097     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3098       Node *use = n->fast_out(i);
3099       if(use->is_Mem() && use->in(MemNode::Address) == n) {
3100         // Load/store to instance's field
3101         memnode_worklist.append_if_missing(use);
3102       } else if (use->is_MemBar()) {
3103         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3104           memnode_worklist.append_if_missing(use);
3105         }
3106       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
3107         Node* addp2 = find_second_addp(use, n);
3108         if (addp2 != NULL) {
3109           alloc_worklist.append_if_missing(addp2);
3110         }
3111         alloc_worklist.append_if_missing(use);
3112       } else if (use->is_Phi() ||
3113                  use->is_CheckCastPP() ||
3114                  use->is_EncodeNarrowPtr() ||
3115                  use->is_DecodeNarrowPtr() ||
3116                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
3117         alloc_worklist.append_if_missing(use);
3118 #ifdef ASSERT
3119       } else if (use->is_Mem()) {
3120         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
3121       } else if (use->is_MergeMem()) {
3122         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3123       } else if (use->is_SafePoint()) {
3124         // Look for MergeMem nodes for calls which reference unique allocation
3125         // (through CheckCastPP nodes) even for debug info.
3126         Node* m = use->in(TypeFunc::Memory);
3127         if (m->is_MergeMem()) {
3128           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3129         }
3130       } else if (use->Opcode() == Op_EncodeISOArray) {
3131         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3132           // EncodeISOArray overwrites destination array
3133           memnode_worklist.append_if_missing(use);
3134         }
3135       } else {
3136         uint op = use->Opcode();
3137         if ((use->in(MemNode::Memory) == n) &&
3138             (op == Op_StrCompressedCopy || op == Op_StrInflatedCopy)) {
3139           // They overwrite memory edge corresponding to destination array,
3140           memnode_worklist.append_if_missing(use);
3141         } else if (!(op == Op_CmpP || op == Op_Conv2B ||
3142               op == Op_CastP2X || op == Op_StoreCM ||
3143               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp || op == Op_HasNegatives ||
3144               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
3145               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar)) {
3146           n->dump();
3147           use->dump();
3148           assert(false, "EA: missing allocation reference path");
3149         }
3150 #endif
3151       }
3152     }
3153 
3154   }
3155 
3156   // Go over all ArrayCopy nodes and if one of the inputs has a unique
3157   // type, record it in the ArrayCopy node so we know what memory this
3158   // node uses/modified.
3159   for (int next = 0; next < arraycopy_worklist.length(); next++) {
3160     ArrayCopyNode* ac = arraycopy_worklist.at(next);
3161     Node* dest = ac->in(ArrayCopyNode::Dest);
3162     if (dest->is_AddP()) {
3163       dest = get_addp_base(dest);
3164     }
3165     JavaObjectNode* jobj = unique_java_object(dest);
3166     if (jobj != NULL) {
3167       Node *base = get_map(jobj->idx());
3168       if (base != NULL) {
3169         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3170         ac->_dest_type = base_t;
3171       }
3172     }
3173     Node* src = ac->in(ArrayCopyNode::Src);
3174     if (src->is_AddP()) {
3175       src = get_addp_base(src);
3176     }
3177     jobj = unique_java_object(src);
3178     if (jobj != NULL) {
3179       Node* base = get_map(jobj->idx());
3180       if (base != NULL) {
3181         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3182         ac->_src_type = base_t;
3183       }
3184     }
3185   }
3186 
3187   // New alias types were created in split_AddP().
3188   uint new_index_end = (uint) _compile->num_alias_types();
3189   assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
3190 
3191   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
3192   //            compute new values for Memory inputs  (the Memory inputs are not
3193   //            actually updated until phase 4.)
3194   if (memnode_worklist.length() == 0)
3195     return;  // nothing to do
3196   while (memnode_worklist.length() != 0) {
3197     Node *n = memnode_worklist.pop();
3198     if (visited.test_set(n->_idx))
3199       continue;
3200     if (n->is_Phi() || n->is_ClearArray()) {
3201       // we don't need to do anything, but the users must be pushed
3202     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
3203       // we don't need to do anything, but the users must be pushed
3204       n = n->as_MemBar()->proj_out(TypeFunc::Memory);
3205       if (n == NULL)
3206         continue;
3207     } else if (n->Opcode() == Op_StrCompressedCopy ||
3208                n->Opcode() == Op_EncodeISOArray) {
3209       // get the memory projection
3210       n = n->find_out_with(Op_SCMemProj);
3211       assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3212     } else {
3213       assert(n->is_Mem(), "memory node required.");
3214       Node *addr = n->in(MemNode::Address);
3215       const Type *addr_t = igvn->type(addr);
3216       if (addr_t == Type::TOP)
3217         continue;
3218       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
3219       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
3220       assert ((uint)alias_idx < new_index_end, "wrong alias index");
3221       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
3222       if (_compile->failing()) {
3223         return;
3224       }
3225       if (mem != n->in(MemNode::Memory)) {
3226         // We delay the memory edge update since we need old one in
3227         // MergeMem code below when instances memory slices are separated.
3228         set_map(n, mem);
3229       }
3230       if (n->is_Load()) {
3231         continue;  // don't push users
3232       } else if (n->is_LoadStore()) {
3233         // get the memory projection
3234         n = n->find_out_with(Op_SCMemProj);
3235         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3236       }
3237     }
3238     // push user on appropriate worklist
3239     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3240       Node *use = n->fast_out(i);
3241       if (use->is_Phi() || use->is_ClearArray()) {
3242         memnode_worklist.append_if_missing(use);
3243       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
3244         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
3245           continue;
3246         memnode_worklist.append_if_missing(use);
3247       } else if (use->is_MemBar()) {
3248         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3249           memnode_worklist.append_if_missing(use);
3250         }
3251 #ifdef ASSERT
3252       } else if(use->is_Mem()) {
3253         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
3254       } else if (use->is_MergeMem()) {
3255         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3256       } else if (use->Opcode() == Op_EncodeISOArray) {
3257         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3258           // EncodeISOArray overwrites destination array
3259           memnode_worklist.append_if_missing(use);
3260         }
3261       } else {
3262         uint op = use->Opcode();
3263         if ((use->in(MemNode::Memory) == n) &&
3264             (op == Op_StrCompressedCopy || op == Op_StrInflatedCopy)) {
3265           // They overwrite memory edge corresponding to destination array,
3266           memnode_worklist.append_if_missing(use);
3267         } else if (!(op == Op_StoreCM ||
3268               (op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&
3269                strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||
3270               op == Op_AryEq || op == Op_StrComp || op == Op_HasNegatives ||
3271               op == Op_StrCompressedCopy || op == Op_StrInflatedCopy ||
3272               op == Op_StrEquals || op == Op_StrIndexOf || op == Op_StrIndexOfChar)) {
3273           n->dump();
3274           use->dump();
3275           assert(false, "EA: missing memory path");
3276         }
3277 #endif
3278       }
3279     }
3280   }
3281 
3282   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
3283   //            Walk each memory slice moving the first node encountered of each
3284   //            instance type to the the input corresponding to its alias index.
3285   uint length = _mergemem_worklist.length();
3286   for( uint next = 0; next < length; ++next ) {
3287     MergeMemNode* nmm = _mergemem_worklist.at(next);
3288     assert(!visited.test_set(nmm->_idx), "should not be visited before");
3289     // Note: we don't want to use MergeMemStream here because we only want to
3290     // scan inputs which exist at the start, not ones we add during processing.
3291     // Note 2: MergeMem may already contains instance memory slices added
3292     // during find_inst_mem() call when memory nodes were processed above.
3293     igvn->hash_delete(nmm);
3294     uint nslices = MIN2(nmm->req(), new_index_start);
3295     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
3296       Node* mem = nmm->in(i);
3297       Node* cur = NULL;
3298       if (mem == NULL || mem->is_top())
3299         continue;
3300       // First, update mergemem by moving memory nodes to corresponding slices
3301       // if their type became more precise since this mergemem was created.
3302       while (mem->is_Mem()) {
3303         const Type *at = igvn->type(mem->in(MemNode::Address));
3304         if (at != Type::TOP) {
3305           assert (at->isa_ptr() != NULL, "pointer type required.");
3306           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
3307           if (idx == i) {
3308             if (cur == NULL)
3309               cur = mem;
3310           } else {
3311             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
3312               nmm->set_memory_at(idx, mem);
3313             }
3314           }
3315         }
3316         mem = mem->in(MemNode::Memory);
3317       }
3318       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
3319       // Find any instance of the current type if we haven't encountered
3320       // already a memory slice of the instance along the memory chain.
3321       for (uint ni = new_index_start; ni < new_index_end; ni++) {
3322         if((uint)_compile->get_general_index(ni) == i) {
3323           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
3324           if (nmm->is_empty_memory(m)) {
3325             Node* result = find_inst_mem(mem, ni, orig_phis);
3326             if (_compile->failing()) {
3327               return;
3328             }
3329             nmm->set_memory_at(ni, result);
3330           }
3331         }
3332       }
3333     }
3334     // Find the rest of instances values
3335     for (uint ni = new_index_start; ni < new_index_end; ni++) {
3336       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
3337       Node* result = step_through_mergemem(nmm, ni, tinst);
3338       if (result == nmm->base_memory()) {
3339         // Didn't find instance memory, search through general slice recursively.
3340         result = nmm->memory_at(_compile->get_general_index(ni));
3341         result = find_inst_mem(result, ni, orig_phis);
3342         if (_compile->failing()) {
3343           return;
3344         }
3345         nmm->set_memory_at(ni, result);
3346       }
3347     }
3348     igvn->hash_insert(nmm);
3349     record_for_optimizer(nmm);
3350   }
3351 
3352   //  Phase 4:  Update the inputs of non-instance memory Phis and
3353   //            the Memory input of memnodes
3354   // First update the inputs of any non-instance Phi's from
3355   // which we split out an instance Phi.  Note we don't have
3356   // to recursively process Phi's encounted on the input memory
3357   // chains as is done in split_memory_phi() since they  will
3358   // also be processed here.
3359   for (int j = 0; j < orig_phis.length(); j++) {
3360     PhiNode *phi = orig_phis.at(j);
3361     int alias_idx = _compile->get_alias_index(phi->adr_type());
3362     igvn->hash_delete(phi);
3363     for (uint i = 1; i < phi->req(); i++) {
3364       Node *mem = phi->in(i);
3365       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
3366       if (_compile->failing()) {
3367         return;
3368       }
3369       if (mem != new_mem) {
3370         phi->set_req(i, new_mem);
3371       }
3372     }
3373     igvn->hash_insert(phi);
3374     record_for_optimizer(phi);
3375   }
3376 
3377   // Update the memory inputs of MemNodes with the value we computed
3378   // in Phase 2 and move stores memory users to corresponding memory slices.
3379   // Disable memory split verification code until the fix for 6984348.
3380   // Currently it produces false negative results since it does not cover all cases.
3381 #if 0 // ifdef ASSERT
3382   visited.Reset();
3383   Node_Stack old_mems(arena, _compile->unique() >> 2);
3384 #endif
3385   for (uint i = 0; i < ideal_nodes.size(); i++) {
3386     Node*    n = ideal_nodes.at(i);
3387     Node* nmem = get_map(n->_idx);
3388     assert(nmem != NULL, "sanity");
3389     if (n->is_Mem()) {
3390 #if 0 // ifdef ASSERT
3391       Node* old_mem = n->in(MemNode::Memory);
3392       if (!visited.test_set(old_mem->_idx)) {
3393         old_mems.push(old_mem, old_mem->outcnt());
3394       }
3395 #endif
3396       assert(n->in(MemNode::Memory) != nmem, "sanity");
3397       if (!n->is_Load()) {
3398         // Move memory users of a store first.
3399         move_inst_mem(n, orig_phis);
3400       }
3401       // Now update memory input
3402       igvn->hash_delete(n);
3403       n->set_req(MemNode::Memory, nmem);
3404       igvn->hash_insert(n);
3405       record_for_optimizer(n);
3406     } else {
3407       assert(n->is_Allocate() || n->is_CheckCastPP() ||
3408              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
3409     }
3410   }
3411 #if 0 // ifdef ASSERT
3412   // Verify that memory was split correctly
3413   while (old_mems.is_nonempty()) {
3414     Node* old_mem = old_mems.node();
3415     uint  old_cnt = old_mems.index();
3416     old_mems.pop();
3417     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
3418   }
3419 #endif
3420 }
3421 
3422 #ifndef PRODUCT
3423 static const char *node_type_names[] = {
3424   "UnknownType",
3425   "JavaObject",
3426   "LocalVar",
3427   "Field",
3428   "Arraycopy"
3429 };
3430 
3431 static const char *esc_names[] = {
3432   "UnknownEscape",
3433   "NoEscape",
3434   "ArgEscape",
3435   "GlobalEscape"
3436 };
3437 
3438 void PointsToNode::dump(bool print_state) const {
3439   NodeType nt = node_type();
3440   tty->print("%s ", node_type_names[(int) nt]);
3441   if (print_state) {
3442     EscapeState es = escape_state();
3443     EscapeState fields_es = fields_escape_state();
3444     tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
3445     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
3446       tty->print("NSR ");
3447   }
3448   if (is_Field()) {
3449     FieldNode* f = (FieldNode*)this;
3450     if (f->is_oop())
3451       tty->print("oop ");
3452     if (f->offset() > 0)
3453       tty->print("+%d ", f->offset());
3454     tty->print("(");
3455     for (BaseIterator i(f); i.has_next(); i.next()) {
3456       PointsToNode* b = i.get();
3457       tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
3458     }
3459     tty->print(" )");
3460   }
3461   tty->print("[");
3462   for (EdgeIterator i(this); i.has_next(); i.next()) {
3463     PointsToNode* e = i.get();
3464     tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
3465   }
3466   tty->print(" [");
3467   for (UseIterator i(this); i.has_next(); i.next()) {
3468     PointsToNode* u = i.get();
3469     bool is_base = false;
3470     if (PointsToNode::is_base_use(u)) {
3471       is_base = true;
3472       u = PointsToNode::get_use_node(u)->as_Field();
3473     }
3474     tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
3475   }
3476   tty->print(" ]]  ");
3477   if (_node == NULL)
3478     tty->print_cr("<null>");
3479   else
3480     _node->dump();
3481 }
3482 
3483 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
3484   bool first = true;
3485   int ptnodes_length = ptnodes_worklist.length();
3486   for (int i = 0; i < ptnodes_length; i++) {
3487     PointsToNode *ptn = ptnodes_worklist.at(i);
3488     if (ptn == NULL || !ptn->is_JavaObject())
3489       continue;
3490     PointsToNode::EscapeState es = ptn->escape_state();
3491     if ((es != PointsToNode::NoEscape) && !Verbose) {
3492       continue;
3493     }
3494     Node* n = ptn->ideal_node();
3495     if (n->is_Allocate() || (n->is_CallStaticJava() &&
3496                              n->as_CallStaticJava()->is_boxing_method())) {
3497       if (first) {
3498         tty->cr();
3499         tty->print("======== Connection graph for ");
3500         _compile->method()->print_short_name();
3501         tty->cr();
3502         first = false;
3503       }
3504       ptn->dump();
3505       // Print all locals and fields which reference this allocation
3506       for (UseIterator j(ptn); j.has_next(); j.next()) {
3507         PointsToNode* use = j.get();
3508         if (use->is_LocalVar()) {
3509           use->dump(Verbose);
3510         } else if (Verbose) {
3511           use->dump();
3512         }
3513       }
3514       tty->cr();
3515     }
3516   }
3517 }
3518 #endif