1 /*
   2  * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "ci/bcEscapeAnalyzer.hpp"
  27 #include "compiler/compileLog.hpp"
  28 #include "libadt/vectset.hpp"
  29 #include "memory/allocation.hpp"
  30 #include "opto/c2compiler.hpp"
  31 #include "opto/arraycopynode.hpp"
  32 #include "opto/callnode.hpp"
  33 #include "opto/cfgnode.hpp"
  34 #include "opto/compile.hpp"
  35 #include "opto/escape.hpp"
  36 #include "opto/phaseX.hpp"
  37 #include "opto/movenode.hpp"
  38 #include "opto/rootnode.hpp"
  39 
  40 ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :
  41   _nodes(C->comp_arena(), C->unique(), C->unique(), NULL),
  42   _in_worklist(C->comp_arena()),
  43   _next_pidx(0),
  44   _collecting(true),
  45   _verify(false),
  46   _compile(C),
  47   _igvn(igvn),
  48   _node_map(C->comp_arena()) {
  49   // Add unknown java object.
  50   add_java_object(C->top(), PointsToNode::GlobalEscape);
  51   phantom_obj = ptnode_adr(C->top()->_idx)->as_JavaObject();
  52   // Add ConP(#NULL) and ConN(#NULL) nodes.
  53   Node* oop_null = igvn->zerocon(T_OBJECT);
  54   assert(oop_null->_idx < nodes_size(), "should be created already");
  55   add_java_object(oop_null, PointsToNode::NoEscape);
  56   null_obj = ptnode_adr(oop_null->_idx)->as_JavaObject();
  57   if (UseCompressedOops) {
  58     Node* noop_null = igvn->zerocon(T_NARROWOOP);
  59     assert(noop_null->_idx < nodes_size(), "should be created already");
  60     map_ideal_node(noop_null, null_obj);
  61   }
  62   _pcmp_neq = NULL; // Should be initialized
  63   _pcmp_eq  = NULL;
  64 }
  65 
  66 bool ConnectionGraph::has_candidates(Compile *C) {
  67   // EA brings benefits only when the code has allocations and/or locks which
  68   // are represented by ideal Macro nodes.
  69   int cnt = C->macro_count();
  70   for (int i = 0; i < cnt; i++) {
  71     Node *n = C->macro_node(i);
  72     if (n->is_Allocate())
  73       return true;
  74     if (n->is_Lock()) {
  75       Node* obj = n->as_Lock()->obj_node()->uncast();
  76       if (!(obj->is_Parm() || obj->is_Con()))
  77         return true;
  78     }
  79     if (n->is_CallStaticJava() &&
  80         n->as_CallStaticJava()->is_boxing_method()) {
  81       return true;
  82     }
  83   }
  84   return false;
  85 }
  86 
  87 void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {
  88   Compile::TracePhase tp("escapeAnalysis", &Phase::timers[Phase::_t_escapeAnalysis]);
  89   ResourceMark rm;
  90 
  91   // Add ConP#NULL and ConN#NULL nodes before ConnectionGraph construction
  92   // to create space for them in ConnectionGraph::_nodes[].
  93   Node* oop_null = igvn->zerocon(T_OBJECT);
  94   Node* noop_null = igvn->zerocon(T_NARROWOOP);
  95   ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn);
  96   // Perform escape analysis
  97   if (congraph->compute_escape()) {
  98     // There are non escaping objects.
  99     C->set_congraph(congraph);
 100   }
 101   // Cleanup.
 102   if (oop_null->outcnt() == 0)
 103     igvn->hash_delete(oop_null);
 104   if (noop_null->outcnt() == 0)
 105     igvn->hash_delete(noop_null);
 106 }
 107 
 108 bool ConnectionGraph::compute_escape() {
 109   Compile* C = _compile;
 110   PhaseGVN* igvn = _igvn;
 111 
 112   // Worklists used by EA.
 113   Unique_Node_List delayed_worklist;
 114   GrowableArray<Node*> alloc_worklist;
 115   GrowableArray<Node*> ptr_cmp_worklist;
 116   GrowableArray<Node*> storestore_worklist;
 117   GrowableArray<ArrayCopyNode*> arraycopy_worklist;
 118   GrowableArray<PointsToNode*>   ptnodes_worklist;
 119   GrowableArray<JavaObjectNode*> java_objects_worklist;
 120   GrowableArray<JavaObjectNode*> non_escaped_worklist;
 121   GrowableArray<FieldNode*>      oop_fields_worklist;
 122   DEBUG_ONLY( GrowableArray<Node*> addp_worklist; )
 123 
 124   { Compile::TracePhase tp("connectionGraph", &Phase::timers[Phase::_t_connectionGraph]);
 125 
 126   // 1. Populate Connection Graph (CG) with PointsTo nodes.
 127   ideal_nodes.map(C->live_nodes(), NULL);  // preallocate space
 128   // Initialize worklist
 129   if (C->root() != NULL) {
 130     ideal_nodes.push(C->root());
 131   }
 132   // Processed ideal nodes are unique on ideal_nodes list
 133   // but several ideal nodes are mapped to the phantom_obj.
 134   // To avoid duplicated entries on the following worklists
 135   // add the phantom_obj only once to them.
 136   ptnodes_worklist.append(phantom_obj);
 137   java_objects_worklist.append(phantom_obj);
 138   for( uint next = 0; next < ideal_nodes.size(); ++next ) {
 139     Node* n = ideal_nodes.at(next);
 140     // Create PointsTo nodes and add them to Connection Graph. Called
 141     // only once per ideal node since ideal_nodes is Unique_Node list.
 142     add_node_to_connection_graph(n, &delayed_worklist);
 143     PointsToNode* ptn = ptnode_adr(n->_idx);
 144     if (ptn != NULL && ptn != phantom_obj) {
 145       ptnodes_worklist.append(ptn);
 146       if (ptn->is_JavaObject()) {
 147         java_objects_worklist.append(ptn->as_JavaObject());
 148         if ((n->is_Allocate() || n->is_CallStaticJava()) &&
 149             (ptn->escape_state() < PointsToNode::GlobalEscape)) {
 150           // Only allocations and java static calls results are interesting.
 151           non_escaped_worklist.append(ptn->as_JavaObject());
 152         }
 153       } else if (ptn->is_Field() && ptn->as_Field()->is_oop()) {
 154         oop_fields_worklist.append(ptn->as_Field());
 155       }
 156     }
 157     if (n->is_MergeMem()) {
 158       // Collect all MergeMem nodes to add memory slices for
 159       // scalar replaceable objects in split_unique_types().
 160       _mergemem_worklist.append(n->as_MergeMem());
 161     } else if (OptimizePtrCompare && n->is_Cmp() &&
 162                (n->Opcode() == Op_CmpP || n->Opcode() == Op_CmpN)) {
 163       // Collect compare pointers nodes.
 164       ptr_cmp_worklist.append(n);
 165     } else if (n->is_MemBarStoreStore()) {
 166       // Collect all MemBarStoreStore nodes so that depending on the
 167       // escape status of the associated Allocate node some of them
 168       // may be eliminated.
 169       storestore_worklist.append(n);
 170     } else if (n->is_MemBar() && (n->Opcode() == Op_MemBarRelease) &&
 171                (n->req() > MemBarNode::Precedent)) {
 172       record_for_optimizer(n);
 173 #ifdef ASSERT
 174     } else if (n->is_AddP()) {
 175       // Collect address nodes for graph verification.
 176       addp_worklist.append(n);
 177 #endif
 178     } else if (n->is_ArrayCopy()) {
 179       // Keep a list of ArrayCopy nodes so if one of its input is non
 180       // escaping, we can record a unique type
 181       arraycopy_worklist.append(n->as_ArrayCopy());
 182     }
 183     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 184       Node* m = n->fast_out(i);   // Get user
 185       ideal_nodes.push(m);
 186     }
 187   }
 188   if (non_escaped_worklist.length() == 0) {
 189     _collecting = false;
 190     return false; // Nothing to do.
 191   }
 192   // Add final simple edges to graph.
 193   while(delayed_worklist.size() > 0) {
 194     Node* n = delayed_worklist.pop();
 195     add_final_edges(n);
 196   }
 197   int ptnodes_length = ptnodes_worklist.length();
 198 
 199 #ifdef ASSERT
 200   if (VerifyConnectionGraph) {
 201     // Verify that no new simple edges could be created and all
 202     // local vars has edges.
 203     _verify = true;
 204     for (int next = 0; next < ptnodes_length; ++next) {
 205       PointsToNode* ptn = ptnodes_worklist.at(next);
 206       add_final_edges(ptn->ideal_node());
 207       if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
 208         ptn->dump();
 209         assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
 210       }
 211     }
 212     _verify = false;
 213   }
 214 #endif
 215   // Bytecode analyzer BCEscapeAnalyzer, used for Call nodes
 216   // processing, calls to CI to resolve symbols (types, fields, methods)
 217   // referenced in bytecode. During symbol resolution VM may throw
 218   // an exception which CI cleans and converts to compilation failure.
 219   if (C->failing())  return false;
 220 
 221   // 2. Finish Graph construction by propagating references to all
 222   //    java objects through graph.
 223   if (!complete_connection_graph(ptnodes_worklist, non_escaped_worklist,
 224                                  java_objects_worklist, oop_fields_worklist)) {
 225     // All objects escaped or hit time or iterations limits.
 226     _collecting = false;
 227     return false;
 228   }
 229 
 230   // 3. Adjust scalar_replaceable state of nonescaping objects and push
 231   //    scalar replaceable allocations on alloc_worklist for processing
 232   //    in split_unique_types().
 233   int non_escaped_length = non_escaped_worklist.length();
 234   for (int next = 0; next < non_escaped_length; next++) {
 235     JavaObjectNode* ptn = non_escaped_worklist.at(next);
 236     bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
 237     Node* n = ptn->ideal_node();
 238     if (n->is_Allocate()) {
 239       n->as_Allocate()->_is_non_escaping = noescape;
 240     }
 241     if (n->is_CallStaticJava()) {
 242       n->as_CallStaticJava()->_is_non_escaping = noescape;
 243     }
 244     if (noescape && ptn->scalar_replaceable()) {
 245       adjust_scalar_replaceable_state(ptn);
 246       if (ptn->scalar_replaceable()) {
 247         alloc_worklist.append(ptn->ideal_node());
 248       }
 249     }
 250   }
 251 
 252 #ifdef ASSERT
 253   if (VerifyConnectionGraph) {
 254     // Verify that graph is complete - no new edges could be added or needed.
 255     verify_connection_graph(ptnodes_worklist, non_escaped_worklist,
 256                             java_objects_worklist, addp_worklist);
 257   }
 258   assert(C->unique() == nodes_size(), "no new ideal nodes should be added during ConnectionGraph build");
 259   assert(null_obj->escape_state() == PointsToNode::NoEscape &&
 260          null_obj->edge_count() == 0 &&
 261          !null_obj->arraycopy_src() &&
 262          !null_obj->arraycopy_dst(), "sanity");
 263 #endif
 264 
 265   _collecting = false;
 266 
 267   } // TracePhase t3("connectionGraph")
 268 
 269   // 4. Optimize ideal graph based on EA information.
 270   bool has_non_escaping_obj = (non_escaped_worklist.length() > 0);
 271   if (has_non_escaping_obj) {
 272     optimize_ideal_graph(ptr_cmp_worklist, storestore_worklist);
 273   }
 274 
 275 #ifndef PRODUCT
 276   if (PrintEscapeAnalysis) {
 277     dump(ptnodes_worklist); // Dump ConnectionGraph
 278   }
 279 #endif
 280 
 281   bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
 282 #ifdef ASSERT
 283   if (VerifyConnectionGraph) {
 284     int alloc_length = alloc_worklist.length();
 285     for (int next = 0; next < alloc_length; ++next) {
 286       Node* n = alloc_worklist.at(next);
 287       PointsToNode* ptn = ptnode_adr(n->_idx);
 288       assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
 289     }
 290   }
 291 #endif
 292 
 293   // 5. Separate memory graph for scalar replaceable allcations.
 294   if (has_scalar_replaceable_candidates &&
 295       C->AliasLevel() >= 3 && EliminateAllocations) {
 296     // Now use the escape information to create unique types for
 297     // scalar replaceable objects.
 298     split_unique_types(alloc_worklist, arraycopy_worklist);
 299     if (C->failing())  return false;
 300     C->print_method(PHASE_AFTER_EA, 2);
 301 
 302 #ifdef ASSERT
 303   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
 304     tty->print("=== No allocations eliminated for ");
 305     C->method()->print_short_name();
 306     if(!EliminateAllocations) {
 307       tty->print(" since EliminateAllocations is off ===");
 308     } else if(!has_scalar_replaceable_candidates) {
 309       tty->print(" since there are no scalar replaceable candidates ===");
 310     } else if(C->AliasLevel() < 3) {
 311       tty->print(" since AliasLevel < 3 ===");
 312     }
 313     tty->cr();
 314 #endif
 315   }
 316   return has_non_escaping_obj;
 317 }
 318 
 319 // Utility function for nodes that load an object
 320 void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 321   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 322   // ThreadLocal has RawPtr type.
 323   const Type* t = _igvn->type(n);
 324   if (t->make_ptr() != NULL) {
 325     Node* adr = n->in(MemNode::Address);
 326 #ifdef ASSERT
 327     if (!adr->is_AddP()) {
 328       assert(_igvn->type(adr)->isa_rawptr(), "sanity");
 329     } else {
 330       assert((ptnode_adr(adr->_idx) == NULL ||
 331               ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
 332     }
 333 #endif
 334     add_local_var_and_edge(n, PointsToNode::NoEscape,
 335                            adr, delayed_worklist);
 336   }
 337 }
 338 
 339 // Populate Connection Graph with PointsTo nodes and create simple
 340 // connection graph edges.
 341 void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 342   assert(!_verify, "this method should not be called for verification");
 343   PhaseGVN* igvn = _igvn;
 344   uint n_idx = n->_idx;
 345   PointsToNode* n_ptn = ptnode_adr(n_idx);
 346   if (n_ptn != NULL)
 347     return; // No need to redefine PointsTo node during first iteration.
 348 
 349   if (n->is_Call()) {
 350     // Arguments to allocation and locking don't escape.
 351     if (n->is_AbstractLock()) {
 352       // Put Lock and Unlock nodes on IGVN worklist to process them during
 353       // first IGVN optimization when escape information is still available.
 354       record_for_optimizer(n);
 355     } else if (n->is_Allocate()) {
 356       add_call_node(n->as_Call());
 357       record_for_optimizer(n);
 358     } else {
 359       if (n->is_CallStaticJava()) {
 360         const char* name = n->as_CallStaticJava()->_name;
 361         if (name != NULL && strcmp(name, "uncommon_trap") == 0)
 362           return; // Skip uncommon traps
 363       }
 364       // Don't mark as processed since call's arguments have to be processed.
 365       delayed_worklist->push(n);
 366       // Check if a call returns an object.
 367       if ((n->as_Call()->returns_pointer() &&
 368            n->as_Call()->proj_out(TypeFunc::Parms) != NULL) ||
 369           (n->is_CallStaticJava() &&
 370            n->as_CallStaticJava()->is_boxing_method())) {
 371         add_call_node(n->as_Call());
 372       }
 373     }
 374     return;
 375   }
 376   // Put this check here to process call arguments since some call nodes
 377   // point to phantom_obj.
 378   if (n_ptn == phantom_obj || n_ptn == null_obj)
 379     return; // Skip predefined nodes.
 380 
 381   int opcode = n->Opcode();
 382   switch (opcode) {
 383     case Op_AddP: {
 384       Node* base = get_addp_base(n);
 385       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 386       // Field nodes are created for all field types. They are used in
 387       // adjust_scalar_replaceable_state() and split_unique_types().
 388       // Note, non-oop fields will have only base edges in Connection
 389       // Graph because such fields are not used for oop loads and stores.
 390       int offset = address_offset(n, igvn);
 391       add_field(n, PointsToNode::NoEscape, offset);
 392       if (ptn_base == NULL) {
 393         delayed_worklist->push(n); // Process it later.
 394       } else {
 395         n_ptn = ptnode_adr(n_idx);
 396         add_base(n_ptn->as_Field(), ptn_base);
 397       }
 398       break;
 399     }
 400     case Op_CastX2P: {
 401       map_ideal_node(n, phantom_obj);
 402       break;
 403     }
 404     case Op_CastPP:
 405     case Op_CheckCastPP:
 406     case Op_EncodeP:
 407     case Op_DecodeN:
 408     case Op_EncodePKlass:
 409     case Op_DecodeNKlass: {
 410       add_local_var_and_edge(n, PointsToNode::NoEscape,
 411                              n->in(1), delayed_worklist);
 412       break;
 413     }
 414     case Op_CMoveP: {
 415       add_local_var(n, PointsToNode::NoEscape);
 416       // Do not add edges during first iteration because some could be
 417       // not defined yet.
 418       delayed_worklist->push(n);
 419       break;
 420     }
 421     case Op_ConP:
 422     case Op_ConN:
 423     case Op_ConNKlass: {
 424       // assume all oop constants globally escape except for null
 425       PointsToNode::EscapeState es;
 426       const Type* t = igvn->type(n);
 427       if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
 428         es = PointsToNode::NoEscape;
 429       } else {
 430         es = PointsToNode::GlobalEscape;
 431       }
 432       add_java_object(n, es);
 433       break;
 434     }
 435     case Op_CreateEx: {
 436       // assume that all exception objects globally escape
 437       map_ideal_node(n, phantom_obj);
 438       break;
 439     }
 440     case Op_LoadKlass:
 441     case Op_LoadNKlass: {
 442       // Unknown class is loaded
 443       map_ideal_node(n, phantom_obj);
 444       break;
 445     }
 446     case Op_LoadP:
 447     case Op_LoadN:
 448     case Op_LoadPLocked: {
 449       add_objload_to_connection_graph(n, delayed_worklist);
 450       break;
 451     }
 452     case Op_Parm: {
 453       map_ideal_node(n, phantom_obj);
 454       break;
 455     }
 456     case Op_PartialSubtypeCheck: {
 457       // Produces Null or notNull and is used in only in CmpP so
 458       // phantom_obj could be used.
 459       map_ideal_node(n, phantom_obj); // Result is unknown
 460       break;
 461     }
 462     case Op_Phi: {
 463       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 464       // ThreadLocal has RawPtr type.
 465       const Type* t = n->as_Phi()->type();
 466       if (t->make_ptr() != NULL) {
 467         add_local_var(n, PointsToNode::NoEscape);
 468         // Do not add edges during first iteration because some could be
 469         // not defined yet.
 470         delayed_worklist->push(n);
 471       }
 472       break;
 473     }
 474     case Op_Proj: {
 475       // we are only interested in the oop result projection from a call
 476       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 477           n->in(0)->as_Call()->returns_pointer()) {
 478         add_local_var_and_edge(n, PointsToNode::NoEscape,
 479                                n->in(0), delayed_worklist);
 480       }
 481       break;
 482     }
 483     case Op_Rethrow: // Exception object escapes
 484     case Op_Return: {
 485       if (n->req() > TypeFunc::Parms &&
 486           igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 487         // Treat Return value as LocalVar with GlobalEscape escape state.
 488         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 489                                n->in(TypeFunc::Parms), delayed_worklist);
 490       }
 491       break;
 492     }
 493     case Op_GetAndSetP:
 494     case Op_GetAndSetN: {
 495       add_objload_to_connection_graph(n, delayed_worklist);
 496       // fallthrough
 497     }
 498     case Op_StoreP:
 499     case Op_StoreN:
 500     case Op_StoreNKlass:
 501     case Op_StorePConditional:
 502     case Op_CompareAndSwapP:
 503     case Op_CompareAndSwapN: {
 504       Node* adr = n->in(MemNode::Address);
 505       const Type *adr_type = igvn->type(adr);
 506       adr_type = adr_type->make_ptr();
 507       if (adr_type == NULL) {
 508         break; // skip dead nodes
 509       }
 510       if (adr_type->isa_oopptr() ||
 511           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
 512                         (adr_type == TypeRawPtr::NOTNULL &&
 513                          adr->in(AddPNode::Address)->is_Proj() &&
 514                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
 515         delayed_worklist->push(n); // Process it later.
 516 #ifdef ASSERT
 517         assert(adr->is_AddP(), "expecting an AddP");
 518         if (adr_type == TypeRawPtr::NOTNULL) {
 519           // Verify a raw address for a store captured by Initialize node.
 520           int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 521           assert(offs != Type::OffsetBot, "offset must be a constant");
 522         }
 523 #endif
 524       } else {
 525         // Ignore copy the displaced header to the BoxNode (OSR compilation).
 526         if (adr->is_BoxLock())
 527           break;
 528         // Stored value escapes in unsafe access.
 529         if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
 530           // Pointer stores in G1 barriers looks like unsafe access.
 531           // Ignore such stores to be able scalar replace non-escaping
 532           // allocations.
 533           if (UseG1GC && adr->is_AddP()) {
 534             Node* base = get_addp_base(adr);
 535             if (base->Opcode() == Op_LoadP &&
 536                 base->in(MemNode::Address)->is_AddP()) {
 537               adr = base->in(MemNode::Address);
 538               Node* tls = get_addp_base(adr);
 539               if (tls->Opcode() == Op_ThreadLocal) {
 540                 int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 541                 if (offs == in_bytes(JavaThread::satb_mark_queue_offset() +
 542                                      PtrQueue::byte_offset_of_buf())) {
 543                   break; // G1 pre barrier previous oop value store.
 544                 }
 545                 if (offs == in_bytes(JavaThread::dirty_card_queue_offset() +
 546                                      PtrQueue::byte_offset_of_buf())) {
 547                   break; // G1 post barrier card address store.
 548                 }
 549               }
 550             }
 551           }
 552           delayed_worklist->push(n); // Process unsafe access later.
 553           break;
 554         }
 555 #ifdef ASSERT
 556         n->dump(1);
 557         assert(false, "not unsafe or G1 barrier raw StoreP");
 558 #endif
 559       }
 560       break;
 561     }
 562     case Op_AryEq:
 563     case Op_StrComp:
 564     case Op_StrEquals:
 565     case Op_StrIndexOf:
 566     case Op_EncodeISOArray: {
 567       add_local_var(n, PointsToNode::ArgEscape);
 568       delayed_worklist->push(n); // Process it later.
 569       break;
 570     }
 571     case Op_ThreadLocal: {
 572       add_java_object(n, PointsToNode::ArgEscape);
 573       break;
 574     }
 575     default:
 576       ; // Do nothing for nodes not related to EA.
 577   }
 578   return;
 579 }
 580 
 581 #ifdef ASSERT
 582 #define ELSE_FAIL(name)                               \
 583       /* Should not be called for not pointer type. */  \
 584       n->dump(1);                                       \
 585       assert(false, name);                              \
 586       break;
 587 #else
 588 #define ELSE_FAIL(name) \
 589       break;
 590 #endif
 591 
 592 // Add final simple edges to graph.
 593 void ConnectionGraph::add_final_edges(Node *n) {
 594   PointsToNode* n_ptn = ptnode_adr(n->_idx);
 595 #ifdef ASSERT
 596   if (_verify && n_ptn->is_JavaObject())
 597     return; // This method does not change graph for JavaObject.
 598 #endif
 599 
 600   if (n->is_Call()) {
 601     process_call_arguments(n->as_Call());
 602     return;
 603   }
 604   assert(n->is_Store() || n->is_LoadStore() ||
 605          (n_ptn != NULL) && (n_ptn->ideal_node() != NULL),
 606          "node should be registered already");
 607   int opcode = n->Opcode();
 608   switch (opcode) {
 609     case Op_AddP: {
 610       Node* base = get_addp_base(n);
 611       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 612       assert(ptn_base != NULL, "field's base should be registered");
 613       add_base(n_ptn->as_Field(), ptn_base);
 614       break;
 615     }
 616     case Op_CastPP:
 617     case Op_CheckCastPP:
 618     case Op_EncodeP:
 619     case Op_DecodeN:
 620     case Op_EncodePKlass:
 621     case Op_DecodeNKlass: {
 622       add_local_var_and_edge(n, PointsToNode::NoEscape,
 623                              n->in(1), NULL);
 624       break;
 625     }
 626     case Op_CMoveP: {
 627       for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
 628         Node* in = n->in(i);
 629         if (in == NULL)
 630           continue;  // ignore NULL
 631         Node* uncast_in = in->uncast();
 632         if (uncast_in->is_top() || uncast_in == n)
 633           continue;  // ignore top or inputs which go back this node
 634         PointsToNode* ptn = ptnode_adr(in->_idx);
 635         assert(ptn != NULL, "node should be registered");
 636         add_edge(n_ptn, ptn);
 637       }
 638       break;
 639     }
 640     case Op_LoadP:
 641     case Op_LoadN:
 642     case Op_LoadPLocked: {
 643       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 644       // ThreadLocal has RawPtr type.
 645       const Type* t = _igvn->type(n);
 646       if (t->make_ptr() != NULL) {
 647         Node* adr = n->in(MemNode::Address);
 648         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 649         break;
 650       }
 651       ELSE_FAIL("Op_LoadP");
 652     }
 653     case Op_Phi: {
 654       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 655       // ThreadLocal has RawPtr type.
 656       const Type* t = n->as_Phi()->type();
 657       if (t->make_ptr() != NULL) {
 658         for (uint i = 1; i < n->req(); i++) {
 659           Node* in = n->in(i);
 660           if (in == NULL)
 661             continue;  // ignore NULL
 662           Node* uncast_in = in->uncast();
 663           if (uncast_in->is_top() || uncast_in == n)
 664             continue;  // ignore top or inputs which go back this node
 665           PointsToNode* ptn = ptnode_adr(in->_idx);
 666           assert(ptn != NULL, "node should be registered");
 667           add_edge(n_ptn, ptn);
 668         }
 669         break;
 670       }
 671       ELSE_FAIL("Op_Phi");
 672     }
 673     case Op_Proj: {
 674       // we are only interested in the oop result projection from a call
 675       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 676           n->in(0)->as_Call()->returns_pointer()) {
 677         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), NULL);
 678         break;
 679       }
 680       ELSE_FAIL("Op_Proj");
 681     }
 682     case Op_Rethrow: // Exception object escapes
 683     case Op_Return: {
 684       if (n->req() > TypeFunc::Parms &&
 685           _igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 686         // Treat Return value as LocalVar with GlobalEscape escape state.
 687         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 688                                n->in(TypeFunc::Parms), NULL);
 689         break;
 690       }
 691       ELSE_FAIL("Op_Return");
 692     }
 693     case Op_StoreP:
 694     case Op_StoreN:
 695     case Op_StoreNKlass:
 696     case Op_StorePConditional:
 697     case Op_CompareAndSwapP:
 698     case Op_CompareAndSwapN:
 699     case Op_GetAndSetP:
 700     case Op_GetAndSetN: {
 701       Node* adr = n->in(MemNode::Address);
 702       const Type *adr_type = _igvn->type(adr);
 703       adr_type = adr_type->make_ptr();
 704 #ifdef ASSERT
 705       if (adr_type == NULL) {
 706         n->dump(1);
 707         assert(adr_type != NULL, "dead node should not be on list");
 708         break;
 709       }
 710 #endif
 711       if (opcode == Op_GetAndSetP || opcode == Op_GetAndSetN) {
 712         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 713       }
 714       if (adr_type->isa_oopptr() ||
 715           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
 716                         (adr_type == TypeRawPtr::NOTNULL &&
 717                          adr->in(AddPNode::Address)->is_Proj() &&
 718                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
 719         // Point Address to Value
 720         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 721         assert(adr_ptn != NULL &&
 722                adr_ptn->as_Field()->is_oop(), "node should be registered");
 723         Node *val = n->in(MemNode::ValueIn);
 724         PointsToNode* ptn = ptnode_adr(val->_idx);
 725         assert(ptn != NULL, "node should be registered");
 726         add_edge(adr_ptn, ptn);
 727         break;
 728       } else if ((opcode == Op_StoreP) && adr_type->isa_rawptr()) {
 729         // Stored value escapes in unsafe access.
 730         Node *val = n->in(MemNode::ValueIn);
 731         PointsToNode* ptn = ptnode_adr(val->_idx);
 732         assert(ptn != NULL, "node should be registered");
 733         set_escape_state(ptn, PointsToNode::GlobalEscape);
 734         // Add edge to object for unsafe access with offset.
 735         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 736         assert(adr_ptn != NULL, "node should be registered");
 737         if (adr_ptn->is_Field()) {
 738           assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
 739           add_edge(adr_ptn, ptn);
 740         }
 741         break;
 742       }
 743       ELSE_FAIL("Op_StoreP");
 744     }
 745     case Op_AryEq:
 746     case Op_StrComp:
 747     case Op_StrEquals:
 748     case Op_StrIndexOf:
 749     case Op_EncodeISOArray: {
 750       // char[] arrays passed to string intrinsic do not escape but
 751       // they are not scalar replaceable. Adjust escape state for them.
 752       // Start from in(2) edge since in(1) is memory edge.
 753       for (uint i = 2; i < n->req(); i++) {
 754         Node* adr = n->in(i);
 755         const Type* at = _igvn->type(adr);
 756         if (!adr->is_top() && at->isa_ptr()) {
 757           assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
 758                  at->isa_ptr() != NULL, "expecting a pointer");
 759           if (adr->is_AddP()) {
 760             adr = get_addp_base(adr);
 761           }
 762           PointsToNode* ptn = ptnode_adr(adr->_idx);
 763           assert(ptn != NULL, "node should be registered");
 764           add_edge(n_ptn, ptn);
 765         }
 766       }
 767       break;
 768     }
 769     default: {
 770       // This method should be called only for EA specific nodes which may
 771       // miss some edges when they were created.
 772 #ifdef ASSERT
 773       n->dump(1);
 774 #endif
 775       guarantee(false, "unknown node");
 776     }
 777   }
 778   return;
 779 }
 780 
 781 void ConnectionGraph::add_call_node(CallNode* call) {
 782   assert(call->returns_pointer(), "only for call which returns pointer");
 783   uint call_idx = call->_idx;
 784   if (call->is_Allocate()) {
 785     Node* k = call->in(AllocateNode::KlassNode);
 786     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
 787     assert(kt != NULL, "TypeKlassPtr  required.");
 788     ciKlass* cik = kt->klass();
 789     PointsToNode::EscapeState es = PointsToNode::NoEscape;
 790     bool scalar_replaceable = true;
 791     if (call->is_AllocateArray()) {
 792       if (!cik->is_array_klass()) { // StressReflectiveCode
 793         es = PointsToNode::GlobalEscape;
 794       } else {
 795         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
 796         if (length < 0 || length > EliminateAllocationArraySizeLimit) {
 797           // Not scalar replaceable if the length is not constant or too big.
 798           scalar_replaceable = false;
 799         }
 800       }
 801     } else {  // Allocate instance
 802       if (cik->is_subclass_of(_compile->env()->Thread_klass()) ||
 803           cik->is_subclass_of(_compile->env()->Reference_klass()) ||
 804          !cik->is_instance_klass() || // StressReflectiveCode
 805           cik->as_instance_klass()->has_finalizer()) {
 806         es = PointsToNode::GlobalEscape;
 807       }
 808     }
 809     add_java_object(call, es);
 810     PointsToNode* ptn = ptnode_adr(call_idx);
 811     if (!scalar_replaceable && ptn->scalar_replaceable()) {
 812       ptn->set_scalar_replaceable(false);
 813     }
 814   } else if (call->is_CallStaticJava()) {
 815     // Call nodes could be different types:
 816     //
 817     // 1. CallDynamicJavaNode (what happened during call is unknown):
 818     //
 819     //    - mapped to GlobalEscape JavaObject node if oop is returned;
 820     //
 821     //    - all oop arguments are escaping globally;
 822     //
 823     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
 824     //
 825     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
 826     //
 827     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
 828     //    - mapped to NoEscape JavaObject node if non-escaping object allocated
 829     //      during call is returned;
 830     //    - mapped to ArgEscape LocalVar node pointed to object arguments
 831     //      which are returned and does not escape during call;
 832     //
 833     //    - oop arguments escaping status is defined by bytecode analysis;
 834     //
 835     // For a static call, we know exactly what method is being called.
 836     // Use bytecode estimator to record whether the call's return value escapes.
 837     ciMethod* meth = call->as_CallJava()->method();
 838     if (meth == NULL) {
 839       const char* name = call->as_CallStaticJava()->_name;
 840       assert(strncmp(name, "_multianewarray", 15) == 0, "TODO: add failed case check");
 841       // Returns a newly allocated unescaped object.
 842       add_java_object(call, PointsToNode::NoEscape);
 843       ptnode_adr(call_idx)->set_scalar_replaceable(false);
 844     } else if (meth->is_boxing_method()) {
 845       // Returns boxing object
 846       PointsToNode::EscapeState es;
 847       vmIntrinsics::ID intr = meth->intrinsic_id();
 848       if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
 849         // It does not escape if object is always allocated.
 850         es = PointsToNode::NoEscape;
 851       } else {
 852         // It escapes globally if object could be loaded from cache.
 853         es = PointsToNode::GlobalEscape;
 854       }
 855       add_java_object(call, es);
 856     } else {
 857       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
 858       call_analyzer->copy_dependencies(_compile->dependencies());
 859       if (call_analyzer->is_return_allocated()) {
 860         // Returns a newly allocated unescaped object, simply
 861         // update dependency information.
 862         // Mark it as NoEscape so that objects referenced by
 863         // it's fields will be marked as NoEscape at least.
 864         add_java_object(call, PointsToNode::NoEscape);
 865         ptnode_adr(call_idx)->set_scalar_replaceable(false);
 866       } else {
 867         // Determine whether any arguments are returned.
 868         const TypeTuple* d = call->tf()->domain();
 869         bool ret_arg = false;
 870         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 871           if (d->field_at(i)->isa_ptr() != NULL &&
 872               call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
 873             ret_arg = true;
 874             break;
 875           }
 876         }
 877         if (ret_arg) {
 878           add_local_var(call, PointsToNode::ArgEscape);
 879         } else {
 880           // Returns unknown object.
 881           map_ideal_node(call, phantom_obj);
 882         }
 883       }
 884     }
 885   } else {
 886     // An other type of call, assume the worst case:
 887     // returned value is unknown and globally escapes.
 888     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
 889     map_ideal_node(call, phantom_obj);
 890   }
 891 }
 892 
 893 void ConnectionGraph::process_call_arguments(CallNode *call) {
 894     bool is_arraycopy = false;
 895     switch (call->Opcode()) {
 896 #ifdef ASSERT
 897     case Op_Allocate:
 898     case Op_AllocateArray:
 899     case Op_Lock:
 900     case Op_Unlock:
 901       assert(false, "should be done already");
 902       break;
 903 #endif
 904     case Op_ArrayCopy:
 905     case Op_CallLeafNoFP:
 906       // Most array copies are ArrayCopy nodes at this point but there
 907       // are still a few direct calls to the copy subroutines (See
 908       // PhaseStringOpts::copy_string())
 909       is_arraycopy = (call->Opcode() == Op_ArrayCopy) ||
 910         call->as_CallLeaf()->is_call_to_arraycopystub();
 911       // fall through
 912     case Op_CallLeaf: {
 913       // Stub calls, objects do not escape but they are not scale replaceable.
 914       // Adjust escape state for outgoing arguments.
 915       const TypeTuple * d = call->tf()->domain();
 916       bool src_has_oops = false;
 917       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 918         const Type* at = d->field_at(i);
 919         Node *arg = call->in(i);
 920         if (arg == NULL) {
 921           continue;
 922         }
 923         const Type *aat = _igvn->type(arg);
 924         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr())
 925           continue;
 926         if (arg->is_AddP()) {
 927           //
 928           // The inline_native_clone() case when the arraycopy stub is called
 929           // after the allocation before Initialize and CheckCastPP nodes.
 930           // Or normal arraycopy for object arrays case.
 931           //
 932           // Set AddP's base (Allocate) as not scalar replaceable since
 933           // pointer to the base (with offset) is passed as argument.
 934           //
 935           arg = get_addp_base(arg);
 936         }
 937         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
 938         assert(arg_ptn != NULL, "should be registered");
 939         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
 940         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
 941           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
 942                  aat->isa_ptr() != NULL, "expecting an Ptr");
 943           bool arg_has_oops = aat->isa_oopptr() &&
 944                               (aat->isa_oopptr()->klass() == NULL || aat->isa_instptr() ||
 945                                (aat->isa_aryptr() && aat->isa_aryptr()->klass()->is_obj_array_klass()));
 946           if (i == TypeFunc::Parms) {
 947             src_has_oops = arg_has_oops;
 948           }
 949           //
 950           // src or dst could be j.l.Object when other is basic type array:
 951           //
 952           //   arraycopy(char[],0,Object*,0,size);
 953           //   arraycopy(Object*,0,char[],0,size);
 954           //
 955           // Don't add edges in such cases.
 956           //
 957           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
 958                                        arg_has_oops && (i > TypeFunc::Parms);
 959 #ifdef ASSERT
 960           if (!(is_arraycopy ||
 961                 (call->as_CallLeaf()->_name != NULL &&
 962                  (strcmp(call->as_CallLeaf()->_name, "g1_wb_pre")  == 0 ||
 963                   strcmp(call->as_CallLeaf()->_name, "g1_wb_post") == 0 ||
 964                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
 965                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32C") == 0 ||
 966                   strcmp(call->as_CallLeaf()->_name, "updateBytesAdler32") == 0 ||
 967                   strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
 968                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
 969                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
 970                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
 971                   strcmp(call->as_CallLeaf()->_name, "ghash_processBlocks") == 0 ||
 972                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
 973                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
 974                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
 975                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
 976                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
 977                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
 978                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
 979                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
 980                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0 ||
 981                   strcmp(call->as_CallLeaf()->_name, "montgomery_multiply") == 0 ||
 982                   strcmp(call->as_CallLeaf()->_name, "montgomery_square") == 0)
 983                  ))) {
 984             call->dump();
 985             fatal(err_msg_res("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name));
 986           }
 987 #endif
 988           // Always process arraycopy's destination object since
 989           // we need to add all possible edges to references in
 990           // source object.
 991           if (arg_esc >= PointsToNode::ArgEscape &&
 992               !arg_is_arraycopy_dest) {
 993             continue;
 994           }
 995           PointsToNode::EscapeState es = PointsToNode::ArgEscape;
 996           if (call->is_ArrayCopy()) {
 997             ArrayCopyNode* ac = call->as_ArrayCopy();
 998             if (ac->is_clonebasic() ||
 999                 ac->is_arraycopy_validated() ||
1000                 ac->is_copyof_validated() ||
1001                 ac->is_copyofrange_validated()) {
1002               es = PointsToNode::NoEscape;
1003             }
1004           }
1005           set_escape_state(arg_ptn, es);
1006           if (arg_is_arraycopy_dest) {
1007             Node* src = call->in(TypeFunc::Parms);
1008             if (src->is_AddP()) {
1009               src = get_addp_base(src);
1010             }
1011             PointsToNode* src_ptn = ptnode_adr(src->_idx);
1012             assert(src_ptn != NULL, "should be registered");
1013             if (arg_ptn != src_ptn) {
1014               // Special arraycopy edge:
1015               // A destination object's field can't have the source object
1016               // as base since objects escape states are not related.
1017               // Only escape state of destination object's fields affects
1018               // escape state of fields in source object.
1019               add_arraycopy(call, es, src_ptn, arg_ptn);
1020             }
1021           }
1022         }
1023       }
1024       break;
1025     }
1026     case Op_CallStaticJava: {
1027       // For a static call, we know exactly what method is being called.
1028       // Use bytecode estimator to record the call's escape affects
1029 #ifdef ASSERT
1030       const char* name = call->as_CallStaticJava()->_name;
1031       assert((name == NULL || strcmp(name, "uncommon_trap") != 0), "normal calls only");
1032 #endif
1033       ciMethod* meth = call->as_CallJava()->method();
1034       if ((meth != NULL) && meth->is_boxing_method()) {
1035         break; // Boxing methods do not modify any oops.
1036       }
1037       BCEscapeAnalyzer* call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
1038       // fall-through if not a Java method or no analyzer information
1039       if (call_analyzer != NULL) {
1040         PointsToNode* call_ptn = ptnode_adr(call->_idx);
1041         const TypeTuple* d = call->tf()->domain();
1042         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1043           const Type* at = d->field_at(i);
1044           int k = i - TypeFunc::Parms;
1045           Node* arg = call->in(i);
1046           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
1047           if (at->isa_ptr() != NULL &&
1048               call_analyzer->is_arg_returned(k)) {
1049             // The call returns arguments.
1050             if (call_ptn != NULL) { // Is call's result used?
1051               assert(call_ptn->is_LocalVar(), "node should be registered");
1052               assert(arg_ptn != NULL, "node should be registered");
1053               add_edge(call_ptn, arg_ptn);
1054             }
1055           }
1056           if (at->isa_oopptr() != NULL &&
1057               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
1058             if (!call_analyzer->is_arg_stack(k)) {
1059               // The argument global escapes
1060               set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1061             } else {
1062               set_escape_state(arg_ptn, PointsToNode::ArgEscape);
1063               if (!call_analyzer->is_arg_local(k)) {
1064                 // The argument itself doesn't escape, but any fields might
1065                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1066               }
1067             }
1068           }
1069         }
1070         if (call_ptn != NULL && call_ptn->is_LocalVar()) {
1071           // The call returns arguments.
1072           assert(call_ptn->edge_count() > 0, "sanity");
1073           if (!call_analyzer->is_return_local()) {
1074             // Returns also unknown object.
1075             add_edge(call_ptn, phantom_obj);
1076           }
1077         }
1078         break;
1079       }
1080     }
1081     default: {
1082       // Fall-through here if not a Java method or no analyzer information
1083       // or some other type of call, assume the worst case: all arguments
1084       // globally escape.
1085       const TypeTuple* d = call->tf()->domain();
1086       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1087         const Type* at = d->field_at(i);
1088         if (at->isa_oopptr() != NULL) {
1089           Node* arg = call->in(i);
1090           if (arg->is_AddP()) {
1091             arg = get_addp_base(arg);
1092           }
1093           assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
1094           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
1095         }
1096       }
1097     }
1098   }
1099 }
1100 
1101 
1102 // Finish Graph construction.
1103 bool ConnectionGraph::complete_connection_graph(
1104                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1105                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1106                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1107                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
1108   // Normally only 1-3 passes needed to build Connection Graph depending
1109   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
1110   // Set limit to 20 to catch situation when something did go wrong and
1111   // bailout Escape Analysis.
1112   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
1113 #define CG_BUILD_ITER_LIMIT 20
1114 
1115   // Propagate GlobalEscape and ArgEscape escape states and check that
1116   // we still have non-escaping objects. The method pushs on _worklist
1117   // Field nodes which reference phantom_object.
1118   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1119     return false; // Nothing to do.
1120   }
1121   // Now propagate references to all JavaObject nodes.
1122   int java_objects_length = java_objects_worklist.length();
1123   elapsedTimer time;
1124   bool timeout = false;
1125   int new_edges = 1;
1126   int iterations = 0;
1127   do {
1128     while ((new_edges > 0) &&
1129            (iterations++ < CG_BUILD_ITER_LIMIT)) {
1130       double start_time = time.seconds();
1131       time.start();
1132       new_edges = 0;
1133       // Propagate references to phantom_object for nodes pushed on _worklist
1134       // by find_non_escaped_objects() and find_field_value().
1135       new_edges += add_java_object_edges(phantom_obj, false);
1136       for (int next = 0; next < java_objects_length; ++next) {
1137         JavaObjectNode* ptn = java_objects_worklist.at(next);
1138         new_edges += add_java_object_edges(ptn, true);
1139 
1140 #define SAMPLE_SIZE 4
1141         if ((next % SAMPLE_SIZE) == 0) {
1142           // Each 4 iterations calculate how much time it will take
1143           // to complete graph construction.
1144           time.stop();
1145           // Poll for requests from shutdown mechanism to quiesce compiler
1146           // because Connection graph construction may take long time.
1147           CompileBroker::maybe_block();
1148           double stop_time = time.seconds();
1149           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
1150           double time_until_end = time_per_iter * (double)(java_objects_length - next);
1151           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
1152             timeout = true;
1153             break; // Timeout
1154           }
1155           start_time = stop_time;
1156           time.start();
1157         }
1158 #undef SAMPLE_SIZE
1159 
1160       }
1161       if (timeout) break;
1162       if (new_edges > 0) {
1163         // Update escape states on each iteration if graph was updated.
1164         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1165           return false; // Nothing to do.
1166         }
1167       }
1168       time.stop();
1169       if (time.seconds() >= EscapeAnalysisTimeout) {
1170         timeout = true;
1171         break;
1172       }
1173     }
1174     if ((iterations < CG_BUILD_ITER_LIMIT) && !timeout) {
1175       time.start();
1176       // Find fields which have unknown value.
1177       int fields_length = oop_fields_worklist.length();
1178       for (int next = 0; next < fields_length; next++) {
1179         FieldNode* field = oop_fields_worklist.at(next);
1180         if (field->edge_count() == 0) {
1181           new_edges += find_field_value(field);
1182           // This code may added new edges to phantom_object.
1183           // Need an other cycle to propagate references to phantom_object.
1184         }
1185       }
1186       time.stop();
1187       if (time.seconds() >= EscapeAnalysisTimeout) {
1188         timeout = true;
1189         break;
1190       }
1191     } else {
1192       new_edges = 0; // Bailout
1193     }
1194   } while (new_edges > 0);
1195 
1196   // Bailout if passed limits.
1197   if ((iterations >= CG_BUILD_ITER_LIMIT) || timeout) {
1198     Compile* C = _compile;
1199     if (C->log() != NULL) {
1200       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
1201       C->log()->text("%s", timeout ? "time" : "iterations");
1202       C->log()->end_elem(" limit'");
1203     }
1204     assert(ExitEscapeAnalysisOnTimeout, err_msg_res("infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
1205            time.seconds(), iterations, nodes_size(), ptnodes_worklist.length()));
1206     // Possible infinite build_connection_graph loop,
1207     // bailout (no changes to ideal graph were made).
1208     return false;
1209   }
1210 #ifdef ASSERT
1211   if (Verbose && PrintEscapeAnalysis) {
1212     tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
1213                   iterations, nodes_size(), ptnodes_worklist.length());
1214   }
1215 #endif
1216 
1217 #undef CG_BUILD_ITER_LIMIT
1218 
1219   // Find fields initialized by NULL for non-escaping Allocations.
1220   int non_escaped_length = non_escaped_worklist.length();
1221   for (int next = 0; next < non_escaped_length; next++) {
1222     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1223     PointsToNode::EscapeState es = ptn->escape_state();
1224     assert(es <= PointsToNode::ArgEscape, "sanity");
1225     if (es == PointsToNode::NoEscape) {
1226       if (find_init_values(ptn, null_obj, _igvn) > 0) {
1227         // Adding references to NULL object does not change escape states
1228         // since it does not escape. Also no fields are added to NULL object.
1229         add_java_object_edges(null_obj, false);
1230       }
1231     }
1232     Node* n = ptn->ideal_node();
1233     if (n->is_Allocate()) {
1234       // The object allocated by this Allocate node will never be
1235       // seen by an other thread. Mark it so that when it is
1236       // expanded no MemBarStoreStore is added.
1237       InitializeNode* ini = n->as_Allocate()->initialization();
1238       if (ini != NULL)
1239         ini->set_does_not_escape();
1240     }
1241   }
1242   return true; // Finished graph construction.
1243 }
1244 
1245 // Propagate GlobalEscape and ArgEscape escape states to all nodes
1246 // and check that we still have non-escaping java objects.
1247 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
1248                                                GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
1249   GrowableArray<PointsToNode*> escape_worklist;
1250   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
1251   int ptnodes_length = ptnodes_worklist.length();
1252   for (int next = 0; next < ptnodes_length; ++next) {
1253     PointsToNode* ptn = ptnodes_worklist.at(next);
1254     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
1255         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
1256       escape_worklist.push(ptn);
1257     }
1258   }
1259   // Set escape states to referenced nodes (edges list).
1260   while (escape_worklist.length() > 0) {
1261     PointsToNode* ptn = escape_worklist.pop();
1262     PointsToNode::EscapeState es  = ptn->escape_state();
1263     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
1264     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
1265         es >= PointsToNode::ArgEscape) {
1266       // GlobalEscape or ArgEscape state of field means it has unknown value.
1267       if (add_edge(ptn, phantom_obj)) {
1268         // New edge was added
1269         add_field_uses_to_worklist(ptn->as_Field());
1270       }
1271     }
1272     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1273       PointsToNode* e = i.get();
1274       if (e->is_Arraycopy()) {
1275         assert(ptn->arraycopy_dst(), "sanity");
1276         // Propagate only fields escape state through arraycopy edge.
1277         if (e->fields_escape_state() < field_es) {
1278           set_fields_escape_state(e, field_es);
1279           escape_worklist.push(e);
1280         }
1281       } else if (es >= field_es) {
1282         // fields_escape_state is also set to 'es' if it is less than 'es'.
1283         if (e->escape_state() < es) {
1284           set_escape_state(e, es);
1285           escape_worklist.push(e);
1286         }
1287       } else {
1288         // Propagate field escape state.
1289         bool es_changed = false;
1290         if (e->fields_escape_state() < field_es) {
1291           set_fields_escape_state(e, field_es);
1292           es_changed = true;
1293         }
1294         if ((e->escape_state() < field_es) &&
1295             e->is_Field() && ptn->is_JavaObject() &&
1296             e->as_Field()->is_oop()) {
1297           // Change escape state of referenced fields.
1298           set_escape_state(e, field_es);
1299           es_changed = true;
1300         } else if (e->escape_state() < es) {
1301           set_escape_state(e, es);
1302           es_changed = true;
1303         }
1304         if (es_changed) {
1305           escape_worklist.push(e);
1306         }
1307       }
1308     }
1309   }
1310   // Remove escaped objects from non_escaped list.
1311   for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
1312     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1313     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
1314       non_escaped_worklist.delete_at(next);
1315     }
1316     if (ptn->escape_state() == PointsToNode::NoEscape) {
1317       // Find fields in non-escaped allocations which have unknown value.
1318       find_init_values(ptn, phantom_obj, NULL);
1319     }
1320   }
1321   return (non_escaped_worklist.length() > 0);
1322 }
1323 
1324 // Add all references to JavaObject node by walking over all uses.
1325 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
1326   int new_edges = 0;
1327   if (populate_worklist) {
1328     // Populate _worklist by uses of jobj's uses.
1329     for (UseIterator i(jobj); i.has_next(); i.next()) {
1330       PointsToNode* use = i.get();
1331       if (use->is_Arraycopy())
1332         continue;
1333       add_uses_to_worklist(use);
1334       if (use->is_Field() && use->as_Field()->is_oop()) {
1335         // Put on worklist all field's uses (loads) and
1336         // related field nodes (same base and offset).
1337         add_field_uses_to_worklist(use->as_Field());
1338       }
1339     }
1340   }
1341   for (int l = 0; l < _worklist.length(); l++) {
1342     PointsToNode* use = _worklist.at(l);
1343     if (PointsToNode::is_base_use(use)) {
1344       // Add reference from jobj to field and from field to jobj (field's base).
1345       use = PointsToNode::get_use_node(use)->as_Field();
1346       if (add_base(use->as_Field(), jobj)) {
1347         new_edges++;
1348       }
1349       continue;
1350     }
1351     assert(!use->is_JavaObject(), "sanity");
1352     if (use->is_Arraycopy()) {
1353       if (jobj == null_obj) // NULL object does not have field edges
1354         continue;
1355       // Added edge from Arraycopy node to arraycopy's source java object
1356       if (add_edge(use, jobj)) {
1357         jobj->set_arraycopy_src();
1358         new_edges++;
1359       }
1360       // and stop here.
1361       continue;
1362     }
1363     if (!add_edge(use, jobj))
1364       continue; // No new edge added, there was such edge already.
1365     new_edges++;
1366     if (use->is_LocalVar()) {
1367       add_uses_to_worklist(use);
1368       if (use->arraycopy_dst()) {
1369         for (EdgeIterator i(use); i.has_next(); i.next()) {
1370           PointsToNode* e = i.get();
1371           if (e->is_Arraycopy()) {
1372             if (jobj == null_obj) // NULL object does not have field edges
1373               continue;
1374             // Add edge from arraycopy's destination java object to Arraycopy node.
1375             if (add_edge(jobj, e)) {
1376               new_edges++;
1377               jobj->set_arraycopy_dst();
1378             }
1379           }
1380         }
1381       }
1382     } else {
1383       // Added new edge to stored in field values.
1384       // Put on worklist all field's uses (loads) and
1385       // related field nodes (same base and offset).
1386       add_field_uses_to_worklist(use->as_Field());
1387     }
1388   }
1389   _worklist.clear();
1390   _in_worklist.Reset();
1391   return new_edges;
1392 }
1393 
1394 // Put on worklist all related field nodes.
1395 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
1396   assert(field->is_oop(), "sanity");
1397   int offset = field->offset();
1398   add_uses_to_worklist(field);
1399   // Loop over all bases of this field and push on worklist Field nodes
1400   // with the same offset and base (since they may reference the same field).
1401   for (BaseIterator i(field); i.has_next(); i.next()) {
1402     PointsToNode* base = i.get();
1403     add_fields_to_worklist(field, base);
1404     // Check if the base was source object of arraycopy and go over arraycopy's
1405     // destination objects since values stored to a field of source object are
1406     // accessable by uses (loads) of fields of destination objects.
1407     if (base->arraycopy_src()) {
1408       for (UseIterator j(base); j.has_next(); j.next()) {
1409         PointsToNode* arycp = j.get();
1410         if (arycp->is_Arraycopy()) {
1411           for (UseIterator k(arycp); k.has_next(); k.next()) {
1412             PointsToNode* abase = k.get();
1413             if (abase->arraycopy_dst() && abase != base) {
1414               // Look for the same arraycopy reference.
1415               add_fields_to_worklist(field, abase);
1416             }
1417           }
1418         }
1419       }
1420     }
1421   }
1422 }
1423 
1424 // Put on worklist all related field nodes.
1425 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
1426   int offset = field->offset();
1427   if (base->is_LocalVar()) {
1428     for (UseIterator j(base); j.has_next(); j.next()) {
1429       PointsToNode* f = j.get();
1430       if (PointsToNode::is_base_use(f)) { // Field
1431         f = PointsToNode::get_use_node(f);
1432         if (f == field || !f->as_Field()->is_oop())
1433           continue;
1434         int offs = f->as_Field()->offset();
1435         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1436           add_to_worklist(f);
1437         }
1438       }
1439     }
1440   } else {
1441     assert(base->is_JavaObject(), "sanity");
1442     if (// Skip phantom_object since it is only used to indicate that
1443         // this field's content globally escapes.
1444         (base != phantom_obj) &&
1445         // NULL object node does not have fields.
1446         (base != null_obj)) {
1447       for (EdgeIterator i(base); i.has_next(); i.next()) {
1448         PointsToNode* f = i.get();
1449         // Skip arraycopy edge since store to destination object field
1450         // does not update value in source object field.
1451         if (f->is_Arraycopy()) {
1452           assert(base->arraycopy_dst(), "sanity");
1453           continue;
1454         }
1455         if (f == field || !f->as_Field()->is_oop())
1456           continue;
1457         int offs = f->as_Field()->offset();
1458         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1459           add_to_worklist(f);
1460         }
1461       }
1462     }
1463   }
1464 }
1465 
1466 // Find fields which have unknown value.
1467 int ConnectionGraph::find_field_value(FieldNode* field) {
1468   // Escaped fields should have init value already.
1469   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
1470   int new_edges = 0;
1471   for (BaseIterator i(field); i.has_next(); i.next()) {
1472     PointsToNode* base = i.get();
1473     if (base->is_JavaObject()) {
1474       // Skip Allocate's fields which will be processed later.
1475       if (base->ideal_node()->is_Allocate())
1476         return 0;
1477       assert(base == null_obj, "only NULL ptr base expected here");
1478     }
1479   }
1480   if (add_edge(field, phantom_obj)) {
1481     // New edge was added
1482     new_edges++;
1483     add_field_uses_to_worklist(field);
1484   }
1485   return new_edges;
1486 }
1487 
1488 // Find fields initializing values for allocations.
1489 int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
1490   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
1491   int new_edges = 0;
1492   Node* alloc = pta->ideal_node();
1493   if (init_val == phantom_obj) {
1494     // Do nothing for Allocate nodes since its fields values are
1495     // "known" unless they are initialized by arraycopy/clone.
1496     if (alloc->is_Allocate() && !pta->arraycopy_dst())
1497       return 0;
1498     assert(pta->arraycopy_dst() || alloc->as_CallStaticJava(), "sanity");
1499 #ifdef ASSERT
1500     if (!pta->arraycopy_dst() && alloc->as_CallStaticJava()->method() == NULL) {
1501       const char* name = alloc->as_CallStaticJava()->_name;
1502       assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
1503     }
1504 #endif
1505     // Non-escaped allocation returned from Java or runtime call have
1506     // unknown values in fields.
1507     for (EdgeIterator i(pta); i.has_next(); i.next()) {
1508       PointsToNode* field = i.get();
1509       if (field->is_Field() && field->as_Field()->is_oop()) {
1510         if (add_edge(field, phantom_obj)) {
1511           // New edge was added
1512           new_edges++;
1513           add_field_uses_to_worklist(field->as_Field());
1514         }
1515       }
1516     }
1517     return new_edges;
1518   }
1519   assert(init_val == null_obj, "sanity");
1520   // Do nothing for Call nodes since its fields values are unknown.
1521   if (!alloc->is_Allocate())
1522     return 0;
1523 
1524   InitializeNode* ini = alloc->as_Allocate()->initialization();
1525   bool visited_bottom_offset = false;
1526   GrowableArray<int> offsets_worklist;
1527 
1528   // Check if an oop field's initializing value is recorded and add
1529   // a corresponding NULL if field's value if it is not recorded.
1530   // Connection Graph does not record a default initialization by NULL
1531   // captured by Initialize node.
1532   //
1533   for (EdgeIterator i(pta); i.has_next(); i.next()) {
1534     PointsToNode* field = i.get(); // Field (AddP)
1535     if (!field->is_Field() || !field->as_Field()->is_oop())
1536       continue; // Not oop field
1537     int offset = field->as_Field()->offset();
1538     if (offset == Type::OffsetBot) {
1539       if (!visited_bottom_offset) {
1540         // OffsetBot is used to reference array's element,
1541         // always add reference to NULL to all Field nodes since we don't
1542         // known which element is referenced.
1543         if (add_edge(field, null_obj)) {
1544           // New edge was added
1545           new_edges++;
1546           add_field_uses_to_worklist(field->as_Field());
1547           visited_bottom_offset = true;
1548         }
1549       }
1550     } else {
1551       // Check only oop fields.
1552       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
1553       if (adr_type->isa_rawptr()) {
1554 #ifdef ASSERT
1555         // Raw pointers are used for initializing stores so skip it
1556         // since it should be recorded already
1557         Node* base = get_addp_base(field->ideal_node());
1558         assert(adr_type->isa_rawptr() && base->is_Proj() &&
1559                (base->in(0) == alloc),"unexpected pointer type");
1560 #endif
1561         continue;
1562       }
1563       if (!offsets_worklist.contains(offset)) {
1564         offsets_worklist.append(offset);
1565         Node* value = NULL;
1566         if (ini != NULL) {
1567           // StoreP::memory_type() == T_ADDRESS
1568           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
1569           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
1570           // Make sure initializing store has the same type as this AddP.
1571           // This AddP may reference non existing field because it is on a
1572           // dead branch of bimorphic call which is not eliminated yet.
1573           if (store != NULL && store->is_Store() &&
1574               store->as_Store()->memory_type() == ft) {
1575             value = store->in(MemNode::ValueIn);
1576 #ifdef ASSERT
1577             if (VerifyConnectionGraph) {
1578               // Verify that AddP already points to all objects the value points to.
1579               PointsToNode* val = ptnode_adr(value->_idx);
1580               assert((val != NULL), "should be processed already");
1581               PointsToNode* missed_obj = NULL;
1582               if (val->is_JavaObject()) {
1583                 if (!field->points_to(val->as_JavaObject())) {
1584                   missed_obj = val;
1585                 }
1586               } else {
1587                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
1588                   tty->print_cr("----------init store has invalid value -----");
1589                   store->dump();
1590                   val->dump();
1591                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
1592                 }
1593                 for (EdgeIterator j(val); j.has_next(); j.next()) {
1594                   PointsToNode* obj = j.get();
1595                   if (obj->is_JavaObject()) {
1596                     if (!field->points_to(obj->as_JavaObject())) {
1597                       missed_obj = obj;
1598                       break;
1599                     }
1600                   }
1601                 }
1602               }
1603               if (missed_obj != NULL) {
1604                 tty->print_cr("----------field---------------------------------");
1605                 field->dump();
1606                 tty->print_cr("----------missed referernce to object-----------");
1607                 missed_obj->dump();
1608                 tty->print_cr("----------object referernced by init store -----");
1609                 store->dump();
1610                 val->dump();
1611                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
1612               }
1613             }
1614 #endif
1615           } else {
1616             // There could be initializing stores which follow allocation.
1617             // For example, a volatile field store is not collected
1618             // by Initialize node.
1619             //
1620             // Need to check for dependent loads to separate such stores from
1621             // stores which follow loads. For now, add initial value NULL so
1622             // that compare pointers optimization works correctly.
1623           }
1624         }
1625         if (value == NULL) {
1626           // A field's initializing value was not recorded. Add NULL.
1627           if (add_edge(field, null_obj)) {
1628             // New edge was added
1629             new_edges++;
1630             add_field_uses_to_worklist(field->as_Field());
1631           }
1632         }
1633       }
1634     }
1635   }
1636   return new_edges;
1637 }
1638 
1639 // Adjust scalar_replaceable state after Connection Graph is built.
1640 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
1641   // Search for non-escaping objects which are not scalar replaceable
1642   // and mark them to propagate the state to referenced objects.
1643 
1644   // 1. An object is not scalar replaceable if the field into which it is
1645   // stored has unknown offset (stored into unknown element of an array).
1646   //
1647   for (UseIterator i(jobj); i.has_next(); i.next()) {
1648     PointsToNode* use = i.get();
1649     if (use->is_Arraycopy()) {
1650       continue;
1651     }
1652     if (use->is_Field()) {
1653       FieldNode* field = use->as_Field();
1654       assert(field->is_oop() && field->scalar_replaceable(), "sanity");
1655       if (field->offset() == Type::OffsetBot) {
1656         jobj->set_scalar_replaceable(false);
1657         return;
1658       }
1659       // 2. An object is not scalar replaceable if the field into which it is
1660       // stored has multiple bases one of which is null.
1661       if (field->base_count() > 1) {
1662         for (BaseIterator i(field); i.has_next(); i.next()) {
1663           PointsToNode* base = i.get();
1664           if (base == null_obj) {
1665             jobj->set_scalar_replaceable(false);
1666             return;
1667           }
1668         }
1669       }
1670     }
1671     assert(use->is_Field() || use->is_LocalVar(), "sanity");
1672     // 3. An object is not scalar replaceable if it is merged with other objects.
1673     for (EdgeIterator j(use); j.has_next(); j.next()) {
1674       PointsToNode* ptn = j.get();
1675       if (ptn->is_JavaObject() && ptn != jobj) {
1676         // Mark all objects.
1677         jobj->set_scalar_replaceable(false);
1678          ptn->set_scalar_replaceable(false);
1679       }
1680     }
1681     if (!jobj->scalar_replaceable()) {
1682       return;
1683     }
1684   }
1685 
1686   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
1687     if (j.get()->is_Arraycopy()) {
1688       continue;
1689     }
1690 
1691     // Non-escaping object node should point only to field nodes.
1692     FieldNode* field = j.get()->as_Field();
1693     int offset = field->as_Field()->offset();
1694 
1695     // 4. An object is not scalar replaceable if it has a field with unknown
1696     // offset (array's element is accessed in loop).
1697     if (offset == Type::OffsetBot) {
1698       jobj->set_scalar_replaceable(false);
1699       return;
1700     }
1701     // 5. Currently an object is not scalar replaceable if a LoadStore node
1702     // access its field since the field value is unknown after it.
1703     //
1704     Node* n = field->ideal_node();
1705     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1706       if (n->fast_out(i)->is_LoadStore()) {
1707         jobj->set_scalar_replaceable(false);
1708         return;
1709       }
1710     }
1711 
1712     // 6. Or the address may point to more then one object. This may produce
1713     // the false positive result (set not scalar replaceable)
1714     // since the flow-insensitive escape analysis can't separate
1715     // the case when stores overwrite the field's value from the case
1716     // when stores happened on different control branches.
1717     //
1718     // Note: it will disable scalar replacement in some cases:
1719     //
1720     //    Point p[] = new Point[1];
1721     //    p[0] = new Point(); // Will be not scalar replaced
1722     //
1723     // but it will save us from incorrect optimizations in next cases:
1724     //
1725     //    Point p[] = new Point[1];
1726     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
1727     //
1728     if (field->base_count() > 1) {
1729       for (BaseIterator i(field); i.has_next(); i.next()) {
1730         PointsToNode* base = i.get();
1731         // Don't take into account LocalVar nodes which
1732         // may point to only one object which should be also
1733         // this field's base by now.
1734         if (base->is_JavaObject() && base != jobj) {
1735           // Mark all bases.
1736           jobj->set_scalar_replaceable(false);
1737           base->set_scalar_replaceable(false);
1738         }
1739       }
1740     }
1741   }
1742 }
1743 
1744 #ifdef ASSERT
1745 void ConnectionGraph::verify_connection_graph(
1746                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1747                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1748                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1749                          GrowableArray<Node*>& addp_worklist) {
1750   // Verify that graph is complete - no new edges could be added.
1751   int java_objects_length = java_objects_worklist.length();
1752   int non_escaped_length  = non_escaped_worklist.length();
1753   int new_edges = 0;
1754   for (int next = 0; next < java_objects_length; ++next) {
1755     JavaObjectNode* ptn = java_objects_worklist.at(next);
1756     new_edges += add_java_object_edges(ptn, true);
1757   }
1758   assert(new_edges == 0, "graph was not complete");
1759   // Verify that escape state is final.
1760   int length = non_escaped_worklist.length();
1761   find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
1762   assert((non_escaped_length == non_escaped_worklist.length()) &&
1763          (non_escaped_length == length) &&
1764          (_worklist.length() == 0), "escape state was not final");
1765 
1766   // Verify fields information.
1767   int addp_length = addp_worklist.length();
1768   for (int next = 0; next < addp_length; ++next ) {
1769     Node* n = addp_worklist.at(next);
1770     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
1771     if (field->is_oop()) {
1772       // Verify that field has all bases
1773       Node* base = get_addp_base(n);
1774       PointsToNode* ptn = ptnode_adr(base->_idx);
1775       if (ptn->is_JavaObject()) {
1776         assert(field->has_base(ptn->as_JavaObject()), "sanity");
1777       } else {
1778         assert(ptn->is_LocalVar(), "sanity");
1779         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1780           PointsToNode* e = i.get();
1781           if (e->is_JavaObject()) {
1782             assert(field->has_base(e->as_JavaObject()), "sanity");
1783           }
1784         }
1785       }
1786       // Verify that all fields have initializing values.
1787       if (field->edge_count() == 0) {
1788         tty->print_cr("----------field does not have references----------");
1789         field->dump();
1790         for (BaseIterator i(field); i.has_next(); i.next()) {
1791           PointsToNode* base = i.get();
1792           tty->print_cr("----------field has next base---------------------");
1793           base->dump();
1794           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
1795             tty->print_cr("----------base has fields-------------------------");
1796             for (EdgeIterator j(base); j.has_next(); j.next()) {
1797               j.get()->dump();
1798             }
1799             tty->print_cr("----------base has references---------------------");
1800             for (UseIterator j(base); j.has_next(); j.next()) {
1801               j.get()->dump();
1802             }
1803           }
1804         }
1805         for (UseIterator i(field); i.has_next(); i.next()) {
1806           i.get()->dump();
1807         }
1808         assert(field->edge_count() > 0, "sanity");
1809       }
1810     }
1811   }
1812 }
1813 #endif
1814 
1815 // Optimize ideal graph.
1816 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
1817                                            GrowableArray<Node*>& storestore_worklist) {
1818   Compile* C = _compile;
1819   PhaseIterGVN* igvn = _igvn;
1820   if (EliminateLocks) {
1821     // Mark locks before changing ideal graph.
1822     int cnt = C->macro_count();
1823     for( int i=0; i < cnt; i++ ) {
1824       Node *n = C->macro_node(i);
1825       if (n->is_AbstractLock()) { // Lock and Unlock nodes
1826         AbstractLockNode* alock = n->as_AbstractLock();
1827         if (!alock->is_non_esc_obj()) {
1828           if (not_global_escape(alock->obj_node())) {
1829             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
1830             // The lock could be marked eliminated by lock coarsening
1831             // code during first IGVN before EA. Replace coarsened flag
1832             // to eliminate all associated locks/unlocks.
1833 #ifdef ASSERT
1834             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
1835 #endif
1836             alock->set_non_esc_obj();
1837           }
1838         }
1839       }
1840     }
1841   }
1842 
1843   if (OptimizePtrCompare) {
1844     // Add ConI(#CC_GT) and ConI(#CC_EQ).
1845     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);
1846     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
1847     // Optimize objects compare.
1848     while (ptr_cmp_worklist.length() != 0) {
1849       Node *n = ptr_cmp_worklist.pop();
1850       Node *res = optimize_ptr_compare(n);
1851       if (res != NULL) {
1852 #ifndef PRODUCT
1853         if (PrintOptimizePtrCompare) {
1854           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"));
1855           if (Verbose) {
1856             n->dump(1);
1857           }
1858         }
1859 #endif
1860         igvn->replace_node(n, res);
1861       }
1862     }
1863     // cleanup
1864     if (_pcmp_neq->outcnt() == 0)
1865       igvn->hash_delete(_pcmp_neq);
1866     if (_pcmp_eq->outcnt()  == 0)
1867       igvn->hash_delete(_pcmp_eq);
1868   }
1869 
1870   // For MemBarStoreStore nodes added in library_call.cpp, check
1871   // escape status of associated AllocateNode and optimize out
1872   // MemBarStoreStore node if the allocated object never escapes.
1873   while (storestore_worklist.length() != 0) {
1874     Node *n = storestore_worklist.pop();
1875     MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
1876     Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
1877     assert (alloc->is_Allocate(), "storestore should point to AllocateNode");
1878     if (not_global_escape(alloc)) {
1879       MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
1880       mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
1881       mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
1882       igvn->register_new_node_with_optimizer(mb);
1883       igvn->replace_node(storestore, mb);
1884     }
1885   }
1886 }
1887 
1888 // Optimize objects compare.
1889 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
1890   assert(OptimizePtrCompare, "sanity");
1891   PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
1892   PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
1893   JavaObjectNode* jobj1 = unique_java_object(n->in(1));
1894   JavaObjectNode* jobj2 = unique_java_object(n->in(2));
1895   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
1896   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
1897 
1898   // Check simple cases first.
1899   if (jobj1 != NULL) {
1900     if (jobj1->escape_state() == PointsToNode::NoEscape) {
1901       if (jobj1 == jobj2) {
1902         // Comparing the same not escaping object.
1903         return _pcmp_eq;
1904       }
1905       Node* obj = jobj1->ideal_node();
1906       // Comparing not escaping allocation.
1907       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1908           !ptn2->points_to(jobj1)) {
1909         return _pcmp_neq; // This includes nullness check.
1910       }
1911     }
1912   }
1913   if (jobj2 != NULL) {
1914     if (jobj2->escape_state() == PointsToNode::NoEscape) {
1915       Node* obj = jobj2->ideal_node();
1916       // Comparing not escaping allocation.
1917       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1918           !ptn1->points_to(jobj2)) {
1919         return _pcmp_neq; // This includes nullness check.
1920       }
1921     }
1922   }
1923   if (jobj1 != NULL && jobj1 != phantom_obj &&
1924       jobj2 != NULL && jobj2 != phantom_obj &&
1925       jobj1->ideal_node()->is_Con() &&
1926       jobj2->ideal_node()->is_Con()) {
1927     // Klass or String constants compare. Need to be careful with
1928     // compressed pointers - compare types of ConN and ConP instead of nodes.
1929     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
1930     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
1931     if (t1->make_ptr() == t2->make_ptr()) {
1932       return _pcmp_eq;
1933     } else {
1934       return _pcmp_neq;
1935     }
1936   }
1937   if (ptn1->meet(ptn2)) {
1938     return NULL; // Sets are not disjoint
1939   }
1940 
1941   // Sets are disjoint.
1942   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
1943   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
1944   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
1945   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
1946   if (set1_has_unknown_ptr && set2_has_null_ptr ||
1947       set2_has_unknown_ptr && set1_has_null_ptr) {
1948     // Check nullness of unknown object.
1949     return NULL;
1950   }
1951 
1952   // Disjointness by itself is not sufficient since
1953   // alias analysis is not complete for escaped objects.
1954   // Disjoint sets are definitely unrelated only when
1955   // at least one set has only not escaping allocations.
1956   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
1957     if (ptn1->non_escaping_allocation()) {
1958       return _pcmp_neq;
1959     }
1960   }
1961   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
1962     if (ptn2->non_escaping_allocation()) {
1963       return _pcmp_neq;
1964     }
1965   }
1966   return NULL;
1967 }
1968 
1969 // Connection Graph constuction functions.
1970 
1971 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
1972   PointsToNode* ptadr = _nodes.at(n->_idx);
1973   if (ptadr != NULL) {
1974     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
1975     return;
1976   }
1977   Compile* C = _compile;
1978   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
1979   _nodes.at_put(n->_idx, ptadr);
1980 }
1981 
1982 void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
1983   PointsToNode* ptadr = _nodes.at(n->_idx);
1984   if (ptadr != NULL) {
1985     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
1986     return;
1987   }
1988   Compile* C = _compile;
1989   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
1990   _nodes.at_put(n->_idx, ptadr);
1991 }
1992 
1993 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
1994   PointsToNode* ptadr = _nodes.at(n->_idx);
1995   if (ptadr != NULL) {
1996     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
1997     return;
1998   }
1999   bool unsafe = false;
2000   bool is_oop = is_oop_field(n, offset, &unsafe);
2001   if (unsafe) {
2002     es = PointsToNode::GlobalEscape;
2003   }
2004   Compile* C = _compile;
2005   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
2006   _nodes.at_put(n->_idx, field);
2007 }
2008 
2009 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
2010                                     PointsToNode* src, PointsToNode* dst) {
2011   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
2012   assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
2013   PointsToNode* ptadr = _nodes.at(n->_idx);
2014   if (ptadr != NULL) {
2015     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
2016     return;
2017   }
2018   Compile* C = _compile;
2019   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
2020   _nodes.at_put(n->_idx, ptadr);
2021   // Add edge from arraycopy node to source object.
2022   (void)add_edge(ptadr, src);
2023   src->set_arraycopy_src();
2024   // Add edge from destination object to arraycopy node.
2025   (void)add_edge(dst, ptadr);
2026   dst->set_arraycopy_dst();
2027 }
2028 
2029 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
2030   const Type* adr_type = n->as_AddP()->bottom_type();
2031   BasicType bt = T_INT;
2032   if (offset == Type::OffsetBot) {
2033     // Check only oop fields.
2034     if (!adr_type->isa_aryptr() ||
2035         (adr_type->isa_aryptr()->klass() == NULL) ||
2036          adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
2037       // OffsetBot is used to reference array's element. Ignore first AddP.
2038       if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
2039         bt = T_OBJECT;
2040       }
2041     }
2042   } else if (offset != oopDesc::klass_offset_in_bytes()) {
2043     if (adr_type->isa_instptr()) {
2044       ciField* field = _compile->alias_type(adr_type->isa_instptr())->field();
2045       if (field != NULL) {
2046         bt = field->layout_type();
2047       } else {
2048         // Check for unsafe oop field access
2049         if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
2050           bt = T_OBJECT;
2051           (*unsafe) = true;
2052         }
2053       }
2054     } else if (adr_type->isa_aryptr()) {
2055       if (offset == arrayOopDesc::length_offset_in_bytes()) {
2056         // Ignore array length load.
2057       } else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
2058         // Ignore first AddP.
2059       } else {
2060         const Type* elemtype = adr_type->isa_aryptr()->elem();
2061         bt = elemtype->array_element_basic_type();
2062       }
2063     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
2064       // Allocation initialization, ThreadLocal field access, unsafe access
2065       if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
2066         bt = T_OBJECT;
2067       }
2068     }
2069   }
2070   return (bt == T_OBJECT || bt == T_NARROWOOP || bt == T_ARRAY);
2071 }
2072 
2073 // Returns unique pointed java object or NULL.
2074 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
2075   assert(!_collecting, "should not call when contructed graph");
2076   // If the node was created after the escape computation we can't answer.
2077   uint idx = n->_idx;
2078   if (idx >= nodes_size()) {
2079     return NULL;
2080   }
2081   PointsToNode* ptn = ptnode_adr(idx);
2082   if (ptn->is_JavaObject()) {
2083     return ptn->as_JavaObject();
2084   }
2085   assert(ptn->is_LocalVar(), "sanity");
2086   // Check all java objects it points to.
2087   JavaObjectNode* jobj = NULL;
2088   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2089     PointsToNode* e = i.get();
2090     if (e->is_JavaObject()) {
2091       if (jobj == NULL) {
2092         jobj = e->as_JavaObject();
2093       } else if (jobj != e) {
2094         return NULL;
2095       }
2096     }
2097   }
2098   return jobj;
2099 }
2100 
2101 // Return true if this node points only to non-escaping allocations.
2102 bool PointsToNode::non_escaping_allocation() {
2103   if (is_JavaObject()) {
2104     Node* n = ideal_node();
2105     if (n->is_Allocate() || n->is_CallStaticJava()) {
2106       return (escape_state() == PointsToNode::NoEscape);
2107     } else {
2108       return false;
2109     }
2110   }
2111   assert(is_LocalVar(), "sanity");
2112   // Check all java objects it points to.
2113   for (EdgeIterator i(this); i.has_next(); i.next()) {
2114     PointsToNode* e = i.get();
2115     if (e->is_JavaObject()) {
2116       Node* n = e->ideal_node();
2117       if ((e->escape_state() != PointsToNode::NoEscape) ||
2118           !(n->is_Allocate() || n->is_CallStaticJava())) {
2119         return false;
2120       }
2121     }
2122   }
2123   return true;
2124 }
2125 
2126 // Return true if we know the node does not escape globally.
2127 bool ConnectionGraph::not_global_escape(Node *n) {
2128   assert(!_collecting, "should not call during graph construction");
2129   // If the node was created after the escape computation we can't answer.
2130   uint idx = n->_idx;
2131   if (idx >= nodes_size()) {
2132     return false;
2133   }
2134   PointsToNode* ptn = ptnode_adr(idx);
2135   PointsToNode::EscapeState es = ptn->escape_state();
2136   // If we have already computed a value, return it.
2137   if (es >= PointsToNode::GlobalEscape)
2138     return false;
2139   if (ptn->is_JavaObject()) {
2140     return true; // (es < PointsToNode::GlobalEscape);
2141   }
2142   assert(ptn->is_LocalVar(), "sanity");
2143   // Check all java objects it points to.
2144   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2145     if (i.get()->escape_state() >= PointsToNode::GlobalEscape)
2146       return false;
2147   }
2148   return true;
2149 }
2150 
2151 
2152 // Helper functions
2153 
2154 // Return true if this node points to specified node or nodes it points to.
2155 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
2156   if (is_JavaObject()) {
2157     return (this == ptn);
2158   }
2159   assert(is_LocalVar() || is_Field(), "sanity");
2160   for (EdgeIterator i(this); i.has_next(); i.next()) {
2161     if (i.get() == ptn)
2162       return true;
2163   }
2164   return false;
2165 }
2166 
2167 // Return true if one node points to an other.
2168 bool PointsToNode::meet(PointsToNode* ptn) {
2169   if (this == ptn) {
2170     return true;
2171   } else if (ptn->is_JavaObject()) {
2172     return this->points_to(ptn->as_JavaObject());
2173   } else if (this->is_JavaObject()) {
2174     return ptn->points_to(this->as_JavaObject());
2175   }
2176   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
2177   int ptn_count =  ptn->edge_count();
2178   for (EdgeIterator i(this); i.has_next(); i.next()) {
2179     PointsToNode* this_e = i.get();
2180     for (int j = 0; j < ptn_count; j++) {
2181       if (this_e == ptn->edge(j))
2182         return true;
2183     }
2184   }
2185   return false;
2186 }
2187 
2188 #ifdef ASSERT
2189 // Return true if bases point to this java object.
2190 bool FieldNode::has_base(JavaObjectNode* jobj) const {
2191   for (BaseIterator i(this); i.has_next(); i.next()) {
2192     if (i.get() == jobj)
2193       return true;
2194   }
2195   return false;
2196 }
2197 #endif
2198 
2199 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
2200   const Type *adr_type = phase->type(adr);
2201   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
2202       adr->in(AddPNode::Address)->is_Proj() &&
2203       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
2204     // We are computing a raw address for a store captured by an Initialize
2205     // compute an appropriate address type. AddP cases #3 and #5 (see below).
2206     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
2207     assert(offs != Type::OffsetBot ||
2208            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
2209            "offset must be a constant or it is initialization of array");
2210     return offs;
2211   }
2212   const TypePtr *t_ptr = adr_type->isa_ptr();
2213   assert(t_ptr != NULL, "must be a pointer type");
2214   return t_ptr->offset();
2215 }
2216 
2217 Node* ConnectionGraph::get_addp_base(Node *addp) {
2218   assert(addp->is_AddP(), "must be AddP");
2219   //
2220   // AddP cases for Base and Address inputs:
2221   // case #1. Direct object's field reference:
2222   //     Allocate
2223   //       |
2224   //     Proj #5 ( oop result )
2225   //       |
2226   //     CheckCastPP (cast to instance type)
2227   //      | |
2228   //     AddP  ( base == address )
2229   //
2230   // case #2. Indirect object's field reference:
2231   //      Phi
2232   //       |
2233   //     CastPP (cast to instance type)
2234   //      | |
2235   //     AddP  ( base == address )
2236   //
2237   // case #3. Raw object's field reference for Initialize node:
2238   //      Allocate
2239   //        |
2240   //      Proj #5 ( oop result )
2241   //  top   |
2242   //     \  |
2243   //     AddP  ( base == top )
2244   //
2245   // case #4. Array's element reference:
2246   //   {CheckCastPP | CastPP}
2247   //     |  | |
2248   //     |  AddP ( array's element offset )
2249   //     |  |
2250   //     AddP ( array's offset )
2251   //
2252   // case #5. Raw object's field reference for arraycopy stub call:
2253   //          The inline_native_clone() case when the arraycopy stub is called
2254   //          after the allocation before Initialize and CheckCastPP nodes.
2255   //      Allocate
2256   //        |
2257   //      Proj #5 ( oop result )
2258   //       | |
2259   //       AddP  ( base == address )
2260   //
2261   // case #6. Constant Pool, ThreadLocal, CastX2P or
2262   //          Raw object's field reference:
2263   //      {ConP, ThreadLocal, CastX2P, raw Load}
2264   //  top   |
2265   //     \  |
2266   //     AddP  ( base == top )
2267   //
2268   // case #7. Klass's field reference.
2269   //      LoadKlass
2270   //       | |
2271   //       AddP  ( base == address )
2272   //
2273   // case #8. narrow Klass's field reference.
2274   //      LoadNKlass
2275   //       |
2276   //      DecodeN
2277   //       | |
2278   //       AddP  ( base == address )
2279   //
2280   Node *base = addp->in(AddPNode::Base);
2281   if (base->uncast()->is_top()) { // The AddP case #3 and #6.
2282     base = addp->in(AddPNode::Address);
2283     while (base->is_AddP()) {
2284       // Case #6 (unsafe access) may have several chained AddP nodes.
2285       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
2286       base = base->in(AddPNode::Address);
2287     }
2288     Node* uncast_base = base->uncast();
2289     int opcode = uncast_base->Opcode();
2290     assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
2291            opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
2292            (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
2293            (uncast_base->is_Proj() && uncast_base->in(0)->is_Allocate()), "sanity");
2294   }
2295   return base;
2296 }
2297 
2298 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
2299   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
2300   Node* addp2 = addp->raw_out(0);
2301   if (addp->outcnt() == 1 && addp2->is_AddP() &&
2302       addp2->in(AddPNode::Base) == n &&
2303       addp2->in(AddPNode::Address) == addp) {
2304     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
2305     //
2306     // Find array's offset to push it on worklist first and
2307     // as result process an array's element offset first (pushed second)
2308     // to avoid CastPP for the array's offset.
2309     // Otherwise the inserted CastPP (LocalVar) will point to what
2310     // the AddP (Field) points to. Which would be wrong since
2311     // the algorithm expects the CastPP has the same point as
2312     // as AddP's base CheckCastPP (LocalVar).
2313     //
2314     //    ArrayAllocation
2315     //     |
2316     //    CheckCastPP
2317     //     |
2318     //    memProj (from ArrayAllocation CheckCastPP)
2319     //     |  ||
2320     //     |  ||   Int (element index)
2321     //     |  ||    |   ConI (log(element size))
2322     //     |  ||    |   /
2323     //     |  ||   LShift
2324     //     |  ||  /
2325     //     |  AddP (array's element offset)
2326     //     |  |
2327     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
2328     //     | / /
2329     //     AddP (array's offset)
2330     //      |
2331     //     Load/Store (memory operation on array's element)
2332     //
2333     return addp2;
2334   }
2335   return NULL;
2336 }
2337 
2338 //
2339 // Adjust the type and inputs of an AddP which computes the
2340 // address of a field of an instance
2341 //
2342 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
2343   PhaseGVN* igvn = _igvn;
2344   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
2345   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
2346   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
2347   if (t == NULL) {
2348     // We are computing a raw address for a store captured by an Initialize
2349     // compute an appropriate address type (cases #3 and #5).
2350     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
2351     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
2352     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
2353     assert(offs != Type::OffsetBot, "offset must be a constant");
2354     t = base_t->add_offset(offs)->is_oopptr();
2355   }
2356   int inst_id =  base_t->instance_id();
2357   assert(!t->is_known_instance() || t->instance_id() == inst_id,
2358                              "old type must be non-instance or match new type");
2359 
2360   // The type 't' could be subclass of 'base_t'.
2361   // As result t->offset() could be large then base_t's size and it will
2362   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
2363   // constructor verifies correctness of the offset.
2364   //
2365   // It could happened on subclass's branch (from the type profiling
2366   // inlining) which was not eliminated during parsing since the exactness
2367   // of the allocation type was not propagated to the subclass type check.
2368   //
2369   // Or the type 't' could be not related to 'base_t' at all.
2370   // It could happened when CHA type is different from MDO type on a dead path
2371   // (for example, from instanceof check) which is not collapsed during parsing.
2372   //
2373   // Do nothing for such AddP node and don't process its users since
2374   // this code branch will go away.
2375   //
2376   if (!t->is_known_instance() &&
2377       !base_t->klass()->is_subtype_of(t->klass())) {
2378      return false; // bail out
2379   }
2380   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
2381   // Do NOT remove the next line: ensure a new alias index is allocated
2382   // for the instance type. Note: C++ will not remove it since the call
2383   // has side effect.
2384   int alias_idx = _compile->get_alias_index(tinst);
2385   igvn->set_type(addp, tinst);
2386   // record the allocation in the node map
2387   set_map(addp, get_map(base->_idx));
2388   // Set addp's Base and Address to 'base'.
2389   Node *abase = addp->in(AddPNode::Base);
2390   Node *adr   = addp->in(AddPNode::Address);
2391   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
2392       adr->in(0)->_idx == (uint)inst_id) {
2393     // Skip AddP cases #3 and #5.
2394   } else {
2395     assert(!abase->is_top(), "sanity"); // AddP case #3
2396     if (abase != base) {
2397       igvn->hash_delete(addp);
2398       addp->set_req(AddPNode::Base, base);
2399       if (abase == adr) {
2400         addp->set_req(AddPNode::Address, base);
2401       } else {
2402         // AddP case #4 (adr is array's element offset AddP node)
2403 #ifdef ASSERT
2404         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
2405         assert(adr->is_AddP() && atype != NULL &&
2406                atype->instance_id() == inst_id, "array's element offset should be processed first");
2407 #endif
2408       }
2409       igvn->hash_insert(addp);
2410     }
2411   }
2412   // Put on IGVN worklist since at least addp's type was changed above.
2413   record_for_optimizer(addp);
2414   return true;
2415 }
2416 
2417 //
2418 // Create a new version of orig_phi if necessary. Returns either the newly
2419 // created phi or an existing phi.  Sets create_new to indicate whether a new
2420 // phi was created.  Cache the last newly created phi in the node map.
2421 //
2422 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
2423   Compile *C = _compile;
2424   PhaseGVN* igvn = _igvn;
2425   new_created = false;
2426   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
2427   // nothing to do if orig_phi is bottom memory or matches alias_idx
2428   if (phi_alias_idx == alias_idx) {
2429     return orig_phi;
2430   }
2431   // Have we recently created a Phi for this alias index?
2432   PhiNode *result = get_map_phi(orig_phi->_idx);
2433   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
2434     return result;
2435   }
2436   // Previous check may fail when the same wide memory Phi was split into Phis
2437   // for different memory slices. Search all Phis for this region.
2438   if (result != NULL) {
2439     Node* region = orig_phi->in(0);
2440     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
2441       Node* phi = region->fast_out(i);
2442       if (phi->is_Phi() &&
2443           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
2444         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
2445         return phi->as_Phi();
2446       }
2447     }
2448   }
2449   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
2450     if (C->do_escape_analysis() == true && !C->failing()) {
2451       // Retry compilation without escape analysis.
2452       // If this is the first failure, the sentinel string will "stick"
2453       // to the Compile object, and the C2Compiler will see it and retry.
2454       C->record_failure(C2Compiler::retry_no_escape_analysis());
2455     }
2456     return NULL;
2457   }
2458   orig_phi_worklist.append_if_missing(orig_phi);
2459   const TypePtr *atype = C->get_adr_type(alias_idx);
2460   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
2461   C->copy_node_notes_to(result, orig_phi);
2462   igvn->set_type(result, result->bottom_type());
2463   record_for_optimizer(result);
2464   set_map(orig_phi, result);
2465   new_created = true;
2466   return result;
2467 }
2468 
2469 //
2470 // Return a new version of Memory Phi "orig_phi" with the inputs having the
2471 // specified alias index.
2472 //
2473 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist) {
2474   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
2475   Compile *C = _compile;
2476   PhaseGVN* igvn = _igvn;
2477   bool new_phi_created;
2478   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
2479   if (!new_phi_created) {
2480     return result;
2481   }
2482   GrowableArray<PhiNode *>  phi_list;
2483   GrowableArray<uint>  cur_input;
2484   PhiNode *phi = orig_phi;
2485   uint idx = 1;
2486   bool finished = false;
2487   while(!finished) {
2488     while (idx < phi->req()) {
2489       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist);
2490       if (mem != NULL && mem->is_Phi()) {
2491         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
2492         if (new_phi_created) {
2493           // found an phi for which we created a new split, push current one on worklist and begin
2494           // processing new one
2495           phi_list.push(phi);
2496           cur_input.push(idx);
2497           phi = mem->as_Phi();
2498           result = newphi;
2499           idx = 1;
2500           continue;
2501         } else {
2502           mem = newphi;
2503         }
2504       }
2505       if (C->failing()) {
2506         return NULL;
2507       }
2508       result->set_req(idx++, mem);
2509     }
2510 #ifdef ASSERT
2511     // verify that the new Phi has an input for each input of the original
2512     assert( phi->req() == result->req(), "must have same number of inputs.");
2513     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
2514 #endif
2515     // Check if all new phi's inputs have specified alias index.
2516     // Otherwise use old phi.
2517     for (uint i = 1; i < phi->req(); i++) {
2518       Node* in = result->in(i);
2519       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
2520     }
2521     // we have finished processing a Phi, see if there are any more to do
2522     finished = (phi_list.length() == 0 );
2523     if (!finished) {
2524       phi = phi_list.pop();
2525       idx = cur_input.pop();
2526       PhiNode *prev_result = get_map_phi(phi->_idx);
2527       prev_result->set_req(idx++, result);
2528       result = prev_result;
2529     }
2530   }
2531   return result;
2532 }
2533 
2534 //
2535 // The next methods are derived from methods in MemNode.
2536 //
2537 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
2538   Node *mem = mmem;
2539   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
2540   // means an array I have not precisely typed yet.  Do not do any
2541   // alias stuff with it any time soon.
2542   if (toop->base() != Type::AnyPtr &&
2543       !(toop->klass() != NULL &&
2544         toop->klass()->is_java_lang_Object() &&
2545         toop->offset() == Type::OffsetBot)) {
2546     mem = mmem->memory_at(alias_idx);
2547     // Update input if it is progress over what we have now
2548   }
2549   return mem;
2550 }
2551 
2552 //
2553 // Move memory users to their memory slices.
2554 //
2555 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
2556   Compile* C = _compile;
2557   PhaseGVN* igvn = _igvn;
2558   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
2559   assert(tp != NULL, "ptr type");
2560   int alias_idx = C->get_alias_index(tp);
2561   int general_idx = C->get_general_index(alias_idx);
2562 
2563   // Move users first
2564   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2565     Node* use = n->fast_out(i);
2566     if (use->is_MergeMem()) {
2567       MergeMemNode* mmem = use->as_MergeMem();
2568       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
2569       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
2570         continue; // Nothing to do
2571       }
2572       // Replace previous general reference to mem node.
2573       uint orig_uniq = C->unique();
2574       Node* m = find_inst_mem(n, general_idx, orig_phis);
2575       assert(orig_uniq == C->unique(), "no new nodes");
2576       mmem->set_memory_at(general_idx, m);
2577       --imax;
2578       --i;
2579     } else if (use->is_MemBar()) {
2580       assert(!use->is_Initialize(), "initializing stores should not be moved");
2581       if (use->req() > MemBarNode::Precedent &&
2582           use->in(MemBarNode::Precedent) == n) {
2583         // Don't move related membars.
2584         record_for_optimizer(use);
2585         continue;
2586       }
2587       tp = use->as_MemBar()->adr_type()->isa_ptr();
2588       if (tp != NULL && C->get_alias_index(tp) == alias_idx ||
2589           alias_idx == general_idx) {
2590         continue; // Nothing to do
2591       }
2592       // Move to general memory slice.
2593       uint orig_uniq = C->unique();
2594       Node* m = find_inst_mem(n, general_idx, orig_phis);
2595       assert(orig_uniq == C->unique(), "no new nodes");
2596       igvn->hash_delete(use);
2597       imax -= use->replace_edge(n, m);
2598       igvn->hash_insert(use);
2599       record_for_optimizer(use);
2600       --i;
2601 #ifdef ASSERT
2602     } else if (use->is_Mem()) {
2603       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
2604         // Don't move related cardmark.
2605         continue;
2606       }
2607       // Memory nodes should have new memory input.
2608       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
2609       assert(tp != NULL, "ptr type");
2610       int idx = C->get_alias_index(tp);
2611       assert(get_map(use->_idx) != NULL || idx == alias_idx,
2612              "Following memory nodes should have new memory input or be on the same memory slice");
2613     } else if (use->is_Phi()) {
2614       // Phi nodes should be split and moved already.
2615       tp = use->as_Phi()->adr_type()->isa_ptr();
2616       assert(tp != NULL, "ptr type");
2617       int idx = C->get_alias_index(tp);
2618       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
2619     } else {
2620       use->dump();
2621       assert(false, "should not be here");
2622 #endif
2623     }
2624   }
2625 }
2626 
2627 //
2628 // Search memory chain of "mem" to find a MemNode whose address
2629 // is the specified alias index.
2630 //
2631 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis) {
2632   if (orig_mem == NULL)
2633     return orig_mem;
2634   Compile* C = _compile;
2635   PhaseGVN* igvn = _igvn;
2636   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
2637   bool is_instance = (toop != NULL) && toop->is_known_instance();
2638   Node *start_mem = C->start()->proj_out(TypeFunc::Memory);
2639   Node *prev = NULL;
2640   Node *result = orig_mem;
2641   while (prev != result) {
2642     prev = result;
2643     if (result == start_mem)
2644       break;  // hit one of our sentinels
2645     if (result->is_Mem()) {
2646       const Type *at = igvn->type(result->in(MemNode::Address));
2647       if (at == Type::TOP)
2648         break; // Dead
2649       assert (at->isa_ptr() != NULL, "pointer type required.");
2650       int idx = C->get_alias_index(at->is_ptr());
2651       if (idx == alias_idx)
2652         break; // Found
2653       if (!is_instance && (at->isa_oopptr() == NULL ||
2654                            !at->is_oopptr()->is_known_instance())) {
2655         break; // Do not skip store to general memory slice.
2656       }
2657       result = result->in(MemNode::Memory);
2658     }
2659     if (!is_instance)
2660       continue;  // don't search further for non-instance types
2661     // skip over a call which does not affect this memory slice
2662     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
2663       Node *proj_in = result->in(0);
2664       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
2665         break;  // hit one of our sentinels
2666       } else if (proj_in->is_Call()) {
2667         // ArrayCopy node processed here as well
2668         CallNode *call = proj_in->as_Call();
2669         if (!call->may_modify(toop, igvn)) {
2670           result = call->in(TypeFunc::Memory);
2671         }
2672       } else if (proj_in->is_Initialize()) {
2673         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
2674         // Stop if this is the initialization for the object instance which
2675         // which contains this memory slice, otherwise skip over it.
2676         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
2677           result = proj_in->in(TypeFunc::Memory);
2678         }
2679       } else if (proj_in->is_MemBar()) {
2680         if (proj_in->in(TypeFunc::Memory)->is_MergeMem() &&
2681             proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->is_Proj() &&
2682             proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->is_ArrayCopy()) {
2683           // clone
2684           ArrayCopyNode* ac = proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->as_ArrayCopy();
2685           if (ac->may_modify(toop, igvn)) {
2686             break;
2687           }
2688         }
2689         result = proj_in->in(TypeFunc::Memory);
2690       }
2691     } else if (result->is_MergeMem()) {
2692       MergeMemNode *mmem = result->as_MergeMem();
2693       result = step_through_mergemem(mmem, alias_idx, toop);
2694       if (result == mmem->base_memory()) {
2695         // Didn't find instance memory, search through general slice recursively.
2696         result = mmem->memory_at(C->get_general_index(alias_idx));
2697         result = find_inst_mem(result, alias_idx, orig_phis);
2698         if (C->failing()) {
2699           return NULL;
2700         }
2701         mmem->set_memory_at(alias_idx, result);
2702       }
2703     } else if (result->is_Phi() &&
2704                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
2705       Node *un = result->as_Phi()->unique_input(igvn);
2706       if (un != NULL) {
2707         orig_phis.append_if_missing(result->as_Phi());
2708         result = un;
2709       } else {
2710         break;
2711       }
2712     } else if (result->is_ClearArray()) {
2713       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
2714         // Can not bypass initialization of the instance
2715         // we are looking for.
2716         break;
2717       }
2718       // Otherwise skip it (the call updated 'result' value).
2719     } else if (result->Opcode() == Op_SCMemProj) {
2720       Node* mem = result->in(0);
2721       Node* adr = NULL;
2722       if (mem->is_LoadStore()) {
2723         adr = mem->in(MemNode::Address);
2724       } else {
2725         assert(mem->Opcode() == Op_EncodeISOArray, "sanity");
2726         adr = mem->in(3); // Memory edge corresponds to destination array
2727       }
2728       const Type *at = igvn->type(adr);
2729       if (at != Type::TOP) {
2730         assert (at->isa_ptr() != NULL, "pointer type required.");
2731         int idx = C->get_alias_index(at->is_ptr());
2732         assert(idx != alias_idx, "Object is not scalar replaceable if a LoadStore node access its field");
2733         break;
2734       }
2735       result = mem->in(MemNode::Memory);
2736     }
2737   }
2738   if (result->is_Phi()) {
2739     PhiNode *mphi = result->as_Phi();
2740     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
2741     const TypePtr *t = mphi->adr_type();
2742     if (!is_instance) {
2743       // Push all non-instance Phis on the orig_phis worklist to update inputs
2744       // during Phase 4 if needed.
2745       orig_phis.append_if_missing(mphi);
2746     } else if (C->get_alias_index(t) != alias_idx) {
2747       // Create a new Phi with the specified alias index type.
2748       result = split_memory_phi(mphi, alias_idx, orig_phis);
2749     }
2750   }
2751   // the result is either MemNode, PhiNode, InitializeNode.
2752   return result;
2753 }
2754 
2755 //
2756 //  Convert the types of unescaped object to instance types where possible,
2757 //  propagate the new type information through the graph, and update memory
2758 //  edges and MergeMem inputs to reflect the new type.
2759 //
2760 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
2761 //  The processing is done in 4 phases:
2762 //
2763 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
2764 //            types for the CheckCastPP for allocations where possible.
2765 //            Propagate the new types through users as follows:
2766 //               casts and Phi:  push users on alloc_worklist
2767 //               AddP:  cast Base and Address inputs to the instance type
2768 //                      push any AddP users on alloc_worklist and push any memnode
2769 //                      users onto memnode_worklist.
2770 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
2771 //            search the Memory chain for a store with the appropriate type
2772 //            address type.  If a Phi is found, create a new version with
2773 //            the appropriate memory slices from each of the Phi inputs.
2774 //            For stores, process the users as follows:
2775 //               MemNode:  push on memnode_worklist
2776 //               MergeMem: push on mergemem_worklist
2777 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
2778 //            moving the first node encountered of each  instance type to the
2779 //            the input corresponding to its alias index.
2780 //            appropriate memory slice.
2781 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
2782 //
2783 // In the following example, the CheckCastPP nodes are the cast of allocation
2784 // results and the allocation of node 29 is unescaped and eligible to be an
2785 // instance type.
2786 //
2787 // We start with:
2788 //
2789 //     7 Parm #memory
2790 //    10  ConI  "12"
2791 //    19  CheckCastPP   "Foo"
2792 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2793 //    29  CheckCastPP   "Foo"
2794 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
2795 //
2796 //    40  StoreP  25   7  20   ... alias_index=4
2797 //    50  StoreP  35  40  30   ... alias_index=4
2798 //    60  StoreP  45  50  20   ... alias_index=4
2799 //    70  LoadP    _  60  30   ... alias_index=4
2800 //    80  Phi     75  50  60   Memory alias_index=4
2801 //    90  LoadP    _  80  30   ... alias_index=4
2802 //   100  LoadP    _  80  20   ... alias_index=4
2803 //
2804 //
2805 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
2806 // and creating a new alias index for node 30.  This gives:
2807 //
2808 //     7 Parm #memory
2809 //    10  ConI  "12"
2810 //    19  CheckCastPP   "Foo"
2811 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2812 //    29  CheckCastPP   "Foo"  iid=24
2813 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2814 //
2815 //    40  StoreP  25   7  20   ... alias_index=4
2816 //    50  StoreP  35  40  30   ... alias_index=6
2817 //    60  StoreP  45  50  20   ... alias_index=4
2818 //    70  LoadP    _  60  30   ... alias_index=6
2819 //    80  Phi     75  50  60   Memory alias_index=4
2820 //    90  LoadP    _  80  30   ... alias_index=6
2821 //   100  LoadP    _  80  20   ... alias_index=4
2822 //
2823 // In phase 2, new memory inputs are computed for the loads and stores,
2824 // And a new version of the phi is created.  In phase 4, the inputs to
2825 // node 80 are updated and then the memory nodes are updated with the
2826 // values computed in phase 2.  This results in:
2827 //
2828 //     7 Parm #memory
2829 //    10  ConI  "12"
2830 //    19  CheckCastPP   "Foo"
2831 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2832 //    29  CheckCastPP   "Foo"  iid=24
2833 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2834 //
2835 //    40  StoreP  25  7   20   ... alias_index=4
2836 //    50  StoreP  35  7   30   ... alias_index=6
2837 //    60  StoreP  45  40  20   ... alias_index=4
2838 //    70  LoadP    _  50  30   ... alias_index=6
2839 //    80  Phi     75  40  60   Memory alias_index=4
2840 //   120  Phi     75  50  50   Memory alias_index=6
2841 //    90  LoadP    _ 120  30   ... alias_index=6
2842 //   100  LoadP    _  80  20   ... alias_index=4
2843 //
2844 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist, GrowableArray<ArrayCopyNode*> &arraycopy_worklist) {
2845   GrowableArray<Node *>  memnode_worklist;
2846   GrowableArray<PhiNode *>  orig_phis;
2847   PhaseIterGVN  *igvn = _igvn;
2848   uint new_index_start = (uint) _compile->num_alias_types();
2849   Arena* arena = Thread::current()->resource_area();
2850   VectorSet visited(arena);
2851   ideal_nodes.clear(); // Reset for use with set_map/get_map.
2852   uint unique_old = _compile->unique();
2853 
2854   //  Phase 1:  Process possible allocations from alloc_worklist.
2855   //  Create instance types for the CheckCastPP for allocations where possible.
2856   //
2857   // (Note: don't forget to change the order of the second AddP node on
2858   //  the alloc_worklist if the order of the worklist processing is changed,
2859   //  see the comment in find_second_addp().)
2860   //
2861   while (alloc_worklist.length() != 0) {
2862     Node *n = alloc_worklist.pop();
2863     uint ni = n->_idx;
2864     if (n->is_Call()) {
2865       CallNode *alloc = n->as_Call();
2866       // copy escape information to call node
2867       PointsToNode* ptn = ptnode_adr(alloc->_idx);
2868       PointsToNode::EscapeState es = ptn->escape_state();
2869       // We have an allocation or call which returns a Java object,
2870       // see if it is unescaped.
2871       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
2872         continue;
2873       // Find CheckCastPP for the allocate or for the return value of a call
2874       n = alloc->result_cast();
2875       if (n == NULL) {            // No uses except Initialize node
2876         if (alloc->is_Allocate()) {
2877           // Set the scalar_replaceable flag for allocation
2878           // so it could be eliminated if it has no uses.
2879           alloc->as_Allocate()->_is_scalar_replaceable = true;
2880         }
2881         if (alloc->is_CallStaticJava()) {
2882           // Set the scalar_replaceable flag for boxing method
2883           // so it could be eliminated if it has no uses.
2884           alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2885         }
2886         continue;
2887       }
2888       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
2889         assert(!alloc->is_Allocate(), "allocation should have unique type");
2890         continue;
2891       }
2892 
2893       // The inline code for Object.clone() casts the allocation result to
2894       // java.lang.Object and then to the actual type of the allocated
2895       // object. Detect this case and use the second cast.
2896       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
2897       // the allocation result is cast to java.lang.Object and then
2898       // to the actual Array type.
2899       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
2900           && (alloc->is_AllocateArray() ||
2901               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
2902         Node *cast2 = NULL;
2903         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2904           Node *use = n->fast_out(i);
2905           if (use->is_CheckCastPP()) {
2906             cast2 = use;
2907             break;
2908           }
2909         }
2910         if (cast2 != NULL) {
2911           n = cast2;
2912         } else {
2913           // Non-scalar replaceable if the allocation type is unknown statically
2914           // (reflection allocation), the object can't be restored during
2915           // deoptimization without precise type.
2916           continue;
2917         }
2918       }
2919 
2920       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
2921       if (t == NULL)
2922         continue;  // not a TypeOopPtr
2923       if (!t->klass_is_exact())
2924         continue; // not an unique type
2925 
2926       if (alloc->is_Allocate()) {
2927         // Set the scalar_replaceable flag for allocation
2928         // so it could be eliminated.
2929         alloc->as_Allocate()->_is_scalar_replaceable = true;
2930       }
2931       if (alloc->is_CallStaticJava()) {
2932         // Set the scalar_replaceable flag for boxing method
2933         // so it could be eliminated.
2934         alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2935       }
2936       set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
2937       // in order for an object to be scalar-replaceable, it must be:
2938       //   - a direct allocation (not a call returning an object)
2939       //   - non-escaping
2940       //   - eligible to be a unique type
2941       //   - not determined to be ineligible by escape analysis
2942       set_map(alloc, n);
2943       set_map(n, alloc);
2944       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
2945       igvn->hash_delete(n);
2946       igvn->set_type(n,  tinst);
2947       n->raise_bottom_type(tinst);
2948       igvn->hash_insert(n);
2949       record_for_optimizer(n);
2950       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
2951 
2952         // First, put on the worklist all Field edges from Connection Graph
2953         // which is more accurate than putting immediate users from Ideal Graph.
2954         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
2955           PointsToNode* tgt = e.get();
2956           if (tgt->is_Arraycopy()) {
2957             continue;
2958           }
2959           Node* use = tgt->ideal_node();
2960           assert(tgt->is_Field() && use->is_AddP(),
2961                  "only AddP nodes are Field edges in CG");
2962           if (use->outcnt() > 0) { // Don't process dead nodes
2963             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
2964             if (addp2 != NULL) {
2965               assert(alloc->is_AllocateArray(),"array allocation was expected");
2966               alloc_worklist.append_if_missing(addp2);
2967             }
2968             alloc_worklist.append_if_missing(use);
2969           }
2970         }
2971 
2972         // An allocation may have an Initialize which has raw stores. Scan
2973         // the users of the raw allocation result and push AddP users
2974         // on alloc_worklist.
2975         Node *raw_result = alloc->proj_out(TypeFunc::Parms);
2976         assert (raw_result != NULL, "must have an allocation result");
2977         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
2978           Node *use = raw_result->fast_out(i);
2979           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
2980             Node* addp2 = find_second_addp(use, raw_result);
2981             if (addp2 != NULL) {
2982               assert(alloc->is_AllocateArray(),"array allocation was expected");
2983               alloc_worklist.append_if_missing(addp2);
2984             }
2985             alloc_worklist.append_if_missing(use);
2986           } else if (use->is_MemBar()) {
2987             memnode_worklist.append_if_missing(use);
2988           }
2989         }
2990       }
2991     } else if (n->is_AddP()) {
2992       JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
2993       if (jobj == NULL || jobj == phantom_obj) {
2994 #ifdef ASSERT
2995         ptnode_adr(get_addp_base(n)->_idx)->dump();
2996         ptnode_adr(n->_idx)->dump();
2997         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
2998 #endif
2999         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3000         return;
3001       }
3002       Node *base = get_map(jobj->idx());  // CheckCastPP node
3003       if (!split_AddP(n, base)) continue; // wrong type from dead path
3004     } else if (n->is_Phi() ||
3005                n->is_CheckCastPP() ||
3006                n->is_EncodeP() ||
3007                n->is_DecodeN() ||
3008                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
3009       if (visited.test_set(n->_idx)) {
3010         assert(n->is_Phi(), "loops only through Phi's");
3011         continue;  // already processed
3012       }
3013       JavaObjectNode* jobj = unique_java_object(n);
3014       if (jobj == NULL || jobj == phantom_obj) {
3015 #ifdef ASSERT
3016         ptnode_adr(n->_idx)->dump();
3017         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3018 #endif
3019         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3020         return;
3021       } else {
3022         Node *val = get_map(jobj->idx());   // CheckCastPP node
3023         TypeNode *tn = n->as_Type();
3024         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
3025         assert(tinst != NULL && tinst->is_known_instance() &&
3026                tinst->instance_id() == jobj->idx() , "instance type expected.");
3027 
3028         const Type *tn_type = igvn->type(tn);
3029         const TypeOopPtr *tn_t;
3030         if (tn_type->isa_narrowoop()) {
3031           tn_t = tn_type->make_ptr()->isa_oopptr();
3032         } else {
3033           tn_t = tn_type->isa_oopptr();
3034         }
3035         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
3036           if (tn_type->isa_narrowoop()) {
3037             tn_type = tinst->make_narrowoop();
3038           } else {
3039             tn_type = tinst;
3040           }
3041           igvn->hash_delete(tn);
3042           igvn->set_type(tn, tn_type);
3043           tn->set_type(tn_type);
3044           igvn->hash_insert(tn);
3045           record_for_optimizer(n);
3046         } else {
3047           assert(tn_type == TypePtr::NULL_PTR ||
3048                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
3049                  "unexpected type");
3050           continue; // Skip dead path with different type
3051         }
3052       }
3053     } else {
3054       debug_only(n->dump();)
3055       assert(false, "EA: unexpected node");
3056       continue;
3057     }
3058     // push allocation's users on appropriate worklist
3059     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3060       Node *use = n->fast_out(i);
3061       if(use->is_Mem() && use->in(MemNode::Address) == n) {
3062         // Load/store to instance's field
3063         memnode_worklist.append_if_missing(use);
3064       } else if (use->is_MemBar()) {
3065         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3066           memnode_worklist.append_if_missing(use);
3067         }
3068       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
3069         Node* addp2 = find_second_addp(use, n);
3070         if (addp2 != NULL) {
3071           alloc_worklist.append_if_missing(addp2);
3072         }
3073         alloc_worklist.append_if_missing(use);
3074       } else if (use->is_Phi() ||
3075                  use->is_CheckCastPP() ||
3076                  use->is_EncodeNarrowPtr() ||
3077                  use->is_DecodeNarrowPtr() ||
3078                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
3079         alloc_worklist.append_if_missing(use);
3080 #ifdef ASSERT
3081       } else if (use->is_Mem()) {
3082         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
3083       } else if (use->is_MergeMem()) {
3084         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3085       } else if (use->is_SafePoint()) {
3086         // Look for MergeMem nodes for calls which reference unique allocation
3087         // (through CheckCastPP nodes) even for debug info.
3088         Node* m = use->in(TypeFunc::Memory);
3089         if (m->is_MergeMem()) {
3090           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3091         }
3092       } else if (use->Opcode() == Op_EncodeISOArray) {
3093         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3094           // EncodeISOArray overwrites destination array
3095           memnode_worklist.append_if_missing(use);
3096         }
3097       } else {
3098         uint op = use->Opcode();
3099         if (!(op == Op_CmpP || op == Op_Conv2B ||
3100               op == Op_CastP2X || op == Op_StoreCM ||
3101               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp ||
3102               op == Op_StrEquals || op == Op_StrIndexOf)) {
3103           n->dump();
3104           use->dump();
3105           assert(false, "EA: missing allocation reference path");
3106         }
3107 #endif
3108       }
3109     }
3110 
3111   }
3112 
3113   // Go over all ArrayCopy nodes and if one of the inputs has a unique
3114   // type, record it in the ArrayCopy node so we know what memory this
3115   // node uses/modified.
3116   for (int next = 0; next < arraycopy_worklist.length(); next++) {
3117     ArrayCopyNode* ac = arraycopy_worklist.at(next);
3118     Node* dest = ac->in(ArrayCopyNode::Dest);
3119     if (dest->is_AddP()) {
3120       dest = get_addp_base(dest);
3121     }
3122     JavaObjectNode* jobj = unique_java_object(dest);
3123     if (jobj != NULL) {
3124       Node *base = get_map(jobj->idx());
3125       if (base != NULL) {
3126         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3127         ac->_dest_type = base_t;
3128       }
3129     }
3130     Node* src = ac->in(ArrayCopyNode::Src);
3131     if (src->is_AddP()) {
3132       src = get_addp_base(src);
3133     }
3134     jobj = unique_java_object(src);
3135     if (jobj != NULL) {
3136       Node* base = get_map(jobj->idx());
3137       if (base != NULL) {
3138         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3139         ac->_src_type = base_t;
3140       }
3141     }
3142   }
3143 
3144   // New alias types were created in split_AddP().
3145   uint new_index_end = (uint) _compile->num_alias_types();
3146   assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
3147 
3148   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
3149   //            compute new values for Memory inputs  (the Memory inputs are not
3150   //            actually updated until phase 4.)
3151   if (memnode_worklist.length() == 0)
3152     return;  // nothing to do
3153   while (memnode_worklist.length() != 0) {
3154     Node *n = memnode_worklist.pop();
3155     if (visited.test_set(n->_idx))
3156       continue;
3157     if (n->is_Phi() || n->is_ClearArray()) {
3158       // we don't need to do anything, but the users must be pushed
3159     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
3160       // we don't need to do anything, but the users must be pushed
3161       n = n->as_MemBar()->proj_out(TypeFunc::Memory);
3162       if (n == NULL)
3163         continue;
3164     } else if (n->Opcode() == Op_EncodeISOArray) {
3165       // get the memory projection
3166       n = n->find_out_with(Op_SCMemProj);
3167       assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3168     } else {
3169       assert(n->is_Mem(), "memory node required.");
3170       Node *addr = n->in(MemNode::Address);
3171       const Type *addr_t = igvn->type(addr);
3172       if (addr_t == Type::TOP)
3173         continue;
3174       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
3175       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
3176       assert ((uint)alias_idx < new_index_end, "wrong alias index");
3177       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
3178       if (_compile->failing()) {
3179         return;
3180       }
3181       if (mem != n->in(MemNode::Memory)) {
3182         // We delay the memory edge update since we need old one in
3183         // MergeMem code below when instances memory slices are separated.
3184         set_map(n, mem);
3185       }
3186       if (n->is_Load()) {
3187         continue;  // don't push users
3188       } else if (n->is_LoadStore()) {
3189         // get the memory projection
3190         n = n->find_out_with(Op_SCMemProj);
3191         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3192       }
3193     }
3194     // push user on appropriate worklist
3195     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3196       Node *use = n->fast_out(i);
3197       if (use->is_Phi() || use->is_ClearArray()) {
3198         memnode_worklist.append_if_missing(use);
3199       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
3200         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
3201           continue;
3202         memnode_worklist.append_if_missing(use);
3203       } else if (use->is_MemBar()) {
3204         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3205           memnode_worklist.append_if_missing(use);
3206         }
3207 #ifdef ASSERT
3208       } else if(use->is_Mem()) {
3209         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
3210       } else if (use->is_MergeMem()) {
3211         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3212       } else if (use->Opcode() == Op_EncodeISOArray) {
3213         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3214           // EncodeISOArray overwrites destination array
3215           memnode_worklist.append_if_missing(use);
3216         }
3217       } else {
3218         uint op = use->Opcode();
3219         if (!(op == Op_StoreCM ||
3220               (op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&
3221                strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||
3222               op == Op_AryEq || op == Op_StrComp ||
3223               op == Op_StrEquals || op == Op_StrIndexOf)) {
3224           n->dump();
3225           use->dump();
3226           assert(false, "EA: missing memory path");
3227         }
3228 #endif
3229       }
3230     }
3231   }
3232 
3233   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
3234   //            Walk each memory slice moving the first node encountered of each
3235   //            instance type to the the input corresponding to its alias index.
3236   uint length = _mergemem_worklist.length();
3237   for( uint next = 0; next < length; ++next ) {
3238     MergeMemNode* nmm = _mergemem_worklist.at(next);
3239     assert(!visited.test_set(nmm->_idx), "should not be visited before");
3240     // Note: we don't want to use MergeMemStream here because we only want to
3241     // scan inputs which exist at the start, not ones we add during processing.
3242     // Note 2: MergeMem may already contains instance memory slices added
3243     // during find_inst_mem() call when memory nodes were processed above.
3244     igvn->hash_delete(nmm);
3245     uint nslices = MIN2(nmm->req(), new_index_start);
3246     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
3247       Node* mem = nmm->in(i);
3248       Node* cur = NULL;
3249       if (mem == NULL || mem->is_top())
3250         continue;
3251       // First, update mergemem by moving memory nodes to corresponding slices
3252       // if their type became more precise since this mergemem was created.
3253       while (mem->is_Mem()) {
3254         const Type *at = igvn->type(mem->in(MemNode::Address));
3255         if (at != Type::TOP) {
3256           assert (at->isa_ptr() != NULL, "pointer type required.");
3257           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
3258           if (idx == i) {
3259             if (cur == NULL)
3260               cur = mem;
3261           } else {
3262             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
3263               nmm->set_memory_at(idx, mem);
3264             }
3265           }
3266         }
3267         mem = mem->in(MemNode::Memory);
3268       }
3269       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
3270       // Find any instance of the current type if we haven't encountered
3271       // already a memory slice of the instance along the memory chain.
3272       for (uint ni = new_index_start; ni < new_index_end; ni++) {
3273         if((uint)_compile->get_general_index(ni) == i) {
3274           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
3275           if (nmm->is_empty_memory(m)) {
3276             Node* result = find_inst_mem(mem, ni, orig_phis);
3277             if (_compile->failing()) {
3278               return;
3279             }
3280             nmm->set_memory_at(ni, result);
3281           }
3282         }
3283       }
3284     }
3285     // Find the rest of instances values
3286     for (uint ni = new_index_start; ni < new_index_end; ni++) {
3287       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
3288       Node* result = step_through_mergemem(nmm, ni, tinst);
3289       if (result == nmm->base_memory()) {
3290         // Didn't find instance memory, search through general slice recursively.
3291         result = nmm->memory_at(_compile->get_general_index(ni));
3292         result = find_inst_mem(result, ni, orig_phis);
3293         if (_compile->failing()) {
3294           return;
3295         }
3296         nmm->set_memory_at(ni, result);
3297       }
3298     }
3299     igvn->hash_insert(nmm);
3300     record_for_optimizer(nmm);
3301   }
3302 
3303   //  Phase 4:  Update the inputs of non-instance memory Phis and
3304   //            the Memory input of memnodes
3305   // First update the inputs of any non-instance Phi's from
3306   // which we split out an instance Phi.  Note we don't have
3307   // to recursively process Phi's encounted on the input memory
3308   // chains as is done in split_memory_phi() since they  will
3309   // also be processed here.
3310   for (int j = 0; j < orig_phis.length(); j++) {
3311     PhiNode *phi = orig_phis.at(j);
3312     int alias_idx = _compile->get_alias_index(phi->adr_type());
3313     igvn->hash_delete(phi);
3314     for (uint i = 1; i < phi->req(); i++) {
3315       Node *mem = phi->in(i);
3316       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
3317       if (_compile->failing()) {
3318         return;
3319       }
3320       if (mem != new_mem) {
3321         phi->set_req(i, new_mem);
3322       }
3323     }
3324     igvn->hash_insert(phi);
3325     record_for_optimizer(phi);
3326   }
3327 
3328   // Update the memory inputs of MemNodes with the value we computed
3329   // in Phase 2 and move stores memory users to corresponding memory slices.
3330   // Disable memory split verification code until the fix for 6984348.
3331   // Currently it produces false negative results since it does not cover all cases.
3332 #if 0 // ifdef ASSERT
3333   visited.Reset();
3334   Node_Stack old_mems(arena, _compile->unique() >> 2);
3335 #endif
3336   for (uint i = 0; i < ideal_nodes.size(); i++) {
3337     Node*    n = ideal_nodes.at(i);
3338     Node* nmem = get_map(n->_idx);
3339     assert(nmem != NULL, "sanity");
3340     if (n->is_Mem()) {
3341 #if 0 // ifdef ASSERT
3342       Node* old_mem = n->in(MemNode::Memory);
3343       if (!visited.test_set(old_mem->_idx)) {
3344         old_mems.push(old_mem, old_mem->outcnt());
3345       }
3346 #endif
3347       assert(n->in(MemNode::Memory) != nmem, "sanity");
3348       if (!n->is_Load()) {
3349         // Move memory users of a store first.
3350         move_inst_mem(n, orig_phis);
3351       }
3352       // Now update memory input
3353       igvn->hash_delete(n);
3354       n->set_req(MemNode::Memory, nmem);
3355       igvn->hash_insert(n);
3356       record_for_optimizer(n);
3357     } else {
3358       assert(n->is_Allocate() || n->is_CheckCastPP() ||
3359              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
3360     }
3361   }
3362 #if 0 // ifdef ASSERT
3363   // Verify that memory was split correctly
3364   while (old_mems.is_nonempty()) {
3365     Node* old_mem = old_mems.node();
3366     uint  old_cnt = old_mems.index();
3367     old_mems.pop();
3368     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
3369   }
3370 #endif
3371 }
3372 
3373 #ifndef PRODUCT
3374 static const char *node_type_names[] = {
3375   "UnknownType",
3376   "JavaObject",
3377   "LocalVar",
3378   "Field",
3379   "Arraycopy"
3380 };
3381 
3382 static const char *esc_names[] = {
3383   "UnknownEscape",
3384   "NoEscape",
3385   "ArgEscape",
3386   "GlobalEscape"
3387 };
3388 
3389 void PointsToNode::dump(bool print_state) const {
3390   NodeType nt = node_type();
3391   tty->print("%s ", node_type_names[(int) nt]);
3392   if (print_state) {
3393     EscapeState es = escape_state();
3394     EscapeState fields_es = fields_escape_state();
3395     tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
3396     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
3397       tty->print("NSR ");
3398   }
3399   if (is_Field()) {
3400     FieldNode* f = (FieldNode*)this;
3401     if (f->is_oop())
3402       tty->print("oop ");
3403     if (f->offset() > 0)
3404       tty->print("+%d ", f->offset());
3405     tty->print("(");
3406     for (BaseIterator i(f); i.has_next(); i.next()) {
3407       PointsToNode* b = i.get();
3408       tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
3409     }
3410     tty->print(" )");
3411   }
3412   tty->print("[");
3413   for (EdgeIterator i(this); i.has_next(); i.next()) {
3414     PointsToNode* e = i.get();
3415     tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
3416   }
3417   tty->print(" [");
3418   for (UseIterator i(this); i.has_next(); i.next()) {
3419     PointsToNode* u = i.get();
3420     bool is_base = false;
3421     if (PointsToNode::is_base_use(u)) {
3422       is_base = true;
3423       u = PointsToNode::get_use_node(u)->as_Field();
3424     }
3425     tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
3426   }
3427   tty->print(" ]]  ");
3428   if (_node == NULL)
3429     tty->print_cr("<null>");
3430   else
3431     _node->dump();
3432 }
3433 
3434 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
3435   bool first = true;
3436   int ptnodes_length = ptnodes_worklist.length();
3437   for (int i = 0; i < ptnodes_length; i++) {
3438     PointsToNode *ptn = ptnodes_worklist.at(i);
3439     if (ptn == NULL || !ptn->is_JavaObject())
3440       continue;
3441     PointsToNode::EscapeState es = ptn->escape_state();
3442     if ((es != PointsToNode::NoEscape) && !Verbose) {
3443       continue;
3444     }
3445     Node* n = ptn->ideal_node();
3446     if (n->is_Allocate() || (n->is_CallStaticJava() &&
3447                              n->as_CallStaticJava()->is_boxing_method())) {
3448       if (first) {
3449         tty->cr();
3450         tty->print("======== Connection graph for ");
3451         _compile->method()->print_short_name();
3452         tty->cr();
3453         first = false;
3454       }
3455       ptn->dump();
3456       // Print all locals and fields which reference this allocation
3457       for (UseIterator j(ptn); j.has_next(); j.next()) {
3458         PointsToNode* use = j.get();
3459         if (use->is_LocalVar()) {
3460           use->dump(Verbose);
3461         } else if (Verbose) {
3462           use->dump();
3463         }
3464       }
3465       tty->cr();
3466     }
3467   }
3468 }
3469 #endif
--- EOF ---