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 == TypeRawPtr::BOTTOM)) {
 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 barier 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 barier 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 == TypeRawPtr::BOTTOM)) {
 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, "aescrypt_encryptBlock") == 0 ||
 966                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
 967                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
 968                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
 969                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
 970                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
 971                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
 972                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
 973                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
 974                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
 975                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
 976                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
 977                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0 ||
 978                   strcmp(call->as_CallLeaf()->_name, "montgomery_multiply") == 0 ||
 979                   strcmp(call->as_CallLeaf()->_name, "montgomery_square") == 0)
 980                  ))) {
 981             call->dump();
 982             fatal(err_msg_res("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name));
 983           }
 984 #endif
 985           // Always process arraycopy's destination object since
 986           // we need to add all possible edges to references in
 987           // source object.
 988           if (arg_esc >= PointsToNode::ArgEscape &&
 989               !arg_is_arraycopy_dest) {
 990             continue;
 991           }
 992           PointsToNode::EscapeState es = PointsToNode::ArgEscape;
 993           if (call->is_ArrayCopy()) {
 994             ArrayCopyNode* ac = call->as_ArrayCopy();
 995             if (ac->is_clonebasic() ||
 996                 ac->is_arraycopy_validated() ||
 997                 ac->is_copyof_validated() ||
 998                 ac->is_copyofrange_validated()) {
 999               es = PointsToNode::NoEscape;
1000             }
1001           }
1002           set_escape_state(arg_ptn, es);
1003           if (arg_is_arraycopy_dest) {
1004             Node* src = call->in(TypeFunc::Parms);
1005             if (src->is_AddP()) {
1006               src = get_addp_base(src);
1007             }
1008             PointsToNode* src_ptn = ptnode_adr(src->_idx);
1009             assert(src_ptn != NULL, "should be registered");
1010             if (arg_ptn != src_ptn) {
1011               // Special arraycopy edge:
1012               // A destination object's field can't have the source object
1013               // as base since objects escape states are not related.
1014               // Only escape state of destination object's fields affects
1015               // escape state of fields in source object.
1016               add_arraycopy(call, es, src_ptn, arg_ptn);
1017             }
1018           }
1019         }
1020       }
1021       break;
1022     }
1023     case Op_CallStaticJava: {
1024       // For a static call, we know exactly what method is being called.
1025       // Use bytecode estimator to record the call's escape affects
1026 #ifdef ASSERT
1027       const char* name = call->as_CallStaticJava()->_name;
1028       assert((name == NULL || strcmp(name, "uncommon_trap") != 0), "normal calls only");
1029 #endif
1030       ciMethod* meth = call->as_CallJava()->method();
1031       if ((meth != NULL) && meth->is_boxing_method()) {
1032         break; // Boxing methods do not modify any oops.
1033       }
1034       BCEscapeAnalyzer* call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
1035       // fall-through if not a Java method or no analyzer information
1036       if (call_analyzer != NULL) {
1037         PointsToNode* call_ptn = ptnode_adr(call->_idx);
1038         const TypeTuple* d = call->tf()->domain();
1039         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1040           const Type* at = d->field_at(i);
1041           int k = i - TypeFunc::Parms;
1042           Node* arg = call->in(i);
1043           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
1044           if (at->isa_ptr() != NULL &&
1045               call_analyzer->is_arg_returned(k)) {
1046             // The call returns arguments.
1047             if (call_ptn != NULL) { // Is call's result used?
1048               assert(call_ptn->is_LocalVar(), "node should be registered");
1049               assert(arg_ptn != NULL, "node should be registered");
1050               add_edge(call_ptn, arg_ptn);
1051             }
1052           }
1053           if (at->isa_oopptr() != NULL &&
1054               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
1055             if (!call_analyzer->is_arg_stack(k)) {
1056               // The argument global escapes
1057               set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1058             } else {
1059               set_escape_state(arg_ptn, PointsToNode::ArgEscape);
1060               if (!call_analyzer->is_arg_local(k)) {
1061                 // The argument itself doesn't escape, but any fields might
1062                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1063               }
1064             }
1065           }
1066         }
1067         if (call_ptn != NULL && call_ptn->is_LocalVar()) {
1068           // The call returns arguments.
1069           assert(call_ptn->edge_count() > 0, "sanity");
1070           if (!call_analyzer->is_return_local()) {
1071             // Returns also unknown object.
1072             add_edge(call_ptn, phantom_obj);
1073           }
1074         }
1075         break;
1076       }
1077     }
1078     default: {
1079       // Fall-through here if not a Java method or no analyzer information
1080       // or some other type of call, assume the worst case: all arguments
1081       // globally escape.
1082       const TypeTuple* d = call->tf()->domain();
1083       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1084         const Type* at = d->field_at(i);
1085         if (at->isa_oopptr() != NULL) {
1086           Node* arg = call->in(i);
1087           if (arg->is_AddP()) {
1088             arg = get_addp_base(arg);
1089           }
1090           assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
1091           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
1092         }
1093       }
1094     }
1095   }
1096 }
1097 
1098 
1099 // Finish Graph construction.
1100 bool ConnectionGraph::complete_connection_graph(
1101                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1102                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1103                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1104                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
1105   // Normally only 1-3 passes needed to build Connection Graph depending
1106   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
1107   // Set limit to 20 to catch situation when something did go wrong and
1108   // bailout Escape Analysis.
1109   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
1110 #define CG_BUILD_ITER_LIMIT 20
1111 
1112   // Propagate GlobalEscape and ArgEscape escape states and check that
1113   // we still have non-escaping objects. The method pushs on _worklist
1114   // Field nodes which reference phantom_object.
1115   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1116     return false; // Nothing to do.
1117   }
1118   // Now propagate references to all JavaObject nodes.
1119   int java_objects_length = java_objects_worklist.length();
1120   elapsedTimer time;
1121   bool timeout = false;
1122   int new_edges = 1;
1123   int iterations = 0;
1124   do {
1125     while ((new_edges > 0) &&
1126            (iterations++ < CG_BUILD_ITER_LIMIT)) {
1127       double start_time = time.seconds();
1128       time.start();
1129       new_edges = 0;
1130       // Propagate references to phantom_object for nodes pushed on _worklist
1131       // by find_non_escaped_objects() and find_field_value().
1132       new_edges += add_java_object_edges(phantom_obj, false);
1133       for (int next = 0; next < java_objects_length; ++next) {
1134         JavaObjectNode* ptn = java_objects_worklist.at(next);
1135         new_edges += add_java_object_edges(ptn, true);
1136 
1137 #define SAMPLE_SIZE 4
1138         if ((next % SAMPLE_SIZE) == 0) {
1139           // Each 4 iterations calculate how much time it will take
1140           // to complete graph construction.
1141           time.stop();
1142           // Poll for requests from shutdown mechanism to quiesce compiler
1143           // because Connection graph construction may take long time.
1144           CompileBroker::maybe_block();
1145           double stop_time = time.seconds();
1146           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
1147           double time_until_end = time_per_iter * (double)(java_objects_length - next);
1148           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
1149             timeout = true;
1150             break; // Timeout
1151           }
1152           start_time = stop_time;
1153           time.start();
1154         }
1155 #undef SAMPLE_SIZE
1156 
1157       }
1158       if (timeout) break;
1159       if (new_edges > 0) {
1160         // Update escape states on each iteration if graph was updated.
1161         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1162           return false; // Nothing to do.
1163         }
1164       }
1165       time.stop();
1166       if (time.seconds() >= EscapeAnalysisTimeout) {
1167         timeout = true;
1168         break;
1169       }
1170     }
1171     if ((iterations < CG_BUILD_ITER_LIMIT) && !timeout) {
1172       time.start();
1173       // Find fields which have unknown value.
1174       int fields_length = oop_fields_worklist.length();
1175       for (int next = 0; next < fields_length; next++) {
1176         FieldNode* field = oop_fields_worklist.at(next);
1177         if (field->edge_count() == 0) {
1178           new_edges += find_field_value(field);
1179           // This code may added new edges to phantom_object.
1180           // Need an other cycle to propagate references to phantom_object.
1181         }
1182       }
1183       time.stop();
1184       if (time.seconds() >= EscapeAnalysisTimeout) {
1185         timeout = true;
1186         break;
1187       }
1188     } else {
1189       new_edges = 0; // Bailout
1190     }
1191   } while (new_edges > 0);
1192 
1193   // Bailout if passed limits.
1194   if ((iterations >= CG_BUILD_ITER_LIMIT) || timeout) {
1195     Compile* C = _compile;
1196     if (C->log() != NULL) {
1197       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
1198       C->log()->text("%s", timeout ? "time" : "iterations");
1199       C->log()->end_elem(" limit'");
1200     }
1201     assert(ExitEscapeAnalysisOnTimeout, err_msg_res("infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
1202            time.seconds(), iterations, nodes_size(), ptnodes_worklist.length()));
1203     // Possible infinite build_connection_graph loop,
1204     // bailout (no changes to ideal graph were made).
1205     return false;
1206   }
1207 #ifdef ASSERT
1208   if (Verbose && PrintEscapeAnalysis) {
1209     tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
1210                   iterations, nodes_size(), ptnodes_worklist.length());
1211   }
1212 #endif
1213 
1214 #undef CG_BUILD_ITER_LIMIT
1215 
1216   // Find fields initialized by NULL for non-escaping Allocations.
1217   int non_escaped_length = non_escaped_worklist.length();
1218   for (int next = 0; next < non_escaped_length; next++) {
1219     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1220     PointsToNode::EscapeState es = ptn->escape_state();
1221     assert(es <= PointsToNode::ArgEscape, "sanity");
1222     if (es == PointsToNode::NoEscape) {
1223       if (find_init_values(ptn, null_obj, _igvn) > 0) {
1224         // Adding references to NULL object does not change escape states
1225         // since it does not escape. Also no fields are added to NULL object.
1226         add_java_object_edges(null_obj, false);
1227       }
1228     }
1229     Node* n = ptn->ideal_node();
1230     if (n->is_Allocate()) {
1231       // The object allocated by this Allocate node will never be
1232       // seen by an other thread. Mark it so that when it is
1233       // expanded no MemBarStoreStore is added.
1234       InitializeNode* ini = n->as_Allocate()->initialization();
1235       if (ini != NULL)
1236         ini->set_does_not_escape();
1237     }
1238   }
1239   return true; // Finished graph construction.
1240 }
1241 
1242 // Propagate GlobalEscape and ArgEscape escape states to all nodes
1243 // and check that we still have non-escaping java objects.
1244 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
1245                                                GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
1246   GrowableArray<PointsToNode*> escape_worklist;
1247   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
1248   int ptnodes_length = ptnodes_worklist.length();
1249   for (int next = 0; next < ptnodes_length; ++next) {
1250     PointsToNode* ptn = ptnodes_worklist.at(next);
1251     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
1252         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
1253       escape_worklist.push(ptn);
1254     }
1255   }
1256   // Set escape states to referenced nodes (edges list).
1257   while (escape_worklist.length() > 0) {
1258     PointsToNode* ptn = escape_worklist.pop();
1259     PointsToNode::EscapeState es  = ptn->escape_state();
1260     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
1261     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
1262         es >= PointsToNode::ArgEscape) {
1263       // GlobalEscape or ArgEscape state of field means it has unknown value.
1264       if (add_edge(ptn, phantom_obj)) {
1265         // New edge was added
1266         add_field_uses_to_worklist(ptn->as_Field());
1267       }
1268     }
1269     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1270       PointsToNode* e = i.get();
1271       if (e->is_Arraycopy()) {
1272         assert(ptn->arraycopy_dst(), "sanity");
1273         // Propagate only fields escape state through arraycopy edge.
1274         if (e->fields_escape_state() < field_es) {
1275           set_fields_escape_state(e, field_es);
1276           escape_worklist.push(e);
1277         }
1278       } else if (es >= field_es) {
1279         // fields_escape_state is also set to 'es' if it is less than 'es'.
1280         if (e->escape_state() < es) {
1281           set_escape_state(e, es);
1282           escape_worklist.push(e);
1283         }
1284       } else {
1285         // Propagate field escape state.
1286         bool es_changed = false;
1287         if (e->fields_escape_state() < field_es) {
1288           set_fields_escape_state(e, field_es);
1289           es_changed = true;
1290         }
1291         if ((e->escape_state() < field_es) &&
1292             e->is_Field() && ptn->is_JavaObject() &&
1293             e->as_Field()->is_oop()) {
1294           // Change escape state of referenced fields.
1295           set_escape_state(e, field_es);
1296           es_changed = true;
1297         } else if (e->escape_state() < es) {
1298           set_escape_state(e, es);
1299           es_changed = true;
1300         }
1301         if (es_changed) {
1302           escape_worklist.push(e);
1303         }
1304       }
1305     }
1306   }
1307   // Remove escaped objects from non_escaped list.
1308   for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
1309     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1310     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
1311       non_escaped_worklist.delete_at(next);
1312     }
1313     if (ptn->escape_state() == PointsToNode::NoEscape) {
1314       // Find fields in non-escaped allocations which have unknown value.
1315       find_init_values(ptn, phantom_obj, NULL);
1316     }
1317   }
1318   return (non_escaped_worklist.length() > 0);
1319 }
1320 
1321 // Add all references to JavaObject node by walking over all uses.
1322 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
1323   int new_edges = 0;
1324   if (populate_worklist) {
1325     // Populate _worklist by uses of jobj's uses.
1326     for (UseIterator i(jobj); i.has_next(); i.next()) {
1327       PointsToNode* use = i.get();
1328       if (use->is_Arraycopy())
1329         continue;
1330       add_uses_to_worklist(use);
1331       if (use->is_Field() && use->as_Field()->is_oop()) {
1332         // Put on worklist all field's uses (loads) and
1333         // related field nodes (same base and offset).
1334         add_field_uses_to_worklist(use->as_Field());
1335       }
1336     }
1337   }
1338   for (int l = 0; l < _worklist.length(); l++) {
1339     PointsToNode* use = _worklist.at(l);
1340     if (PointsToNode::is_base_use(use)) {
1341       // Add reference from jobj to field and from field to jobj (field's base).
1342       use = PointsToNode::get_use_node(use)->as_Field();
1343       if (add_base(use->as_Field(), jobj)) {
1344         new_edges++;
1345       }
1346       continue;
1347     }
1348     assert(!use->is_JavaObject(), "sanity");
1349     if (use->is_Arraycopy()) {
1350       if (jobj == null_obj) // NULL object does not have field edges
1351         continue;
1352       // Added edge from Arraycopy node to arraycopy's source java object
1353       if (add_edge(use, jobj)) {
1354         jobj->set_arraycopy_src();
1355         new_edges++;
1356       }
1357       // and stop here.
1358       continue;
1359     }
1360     if (!add_edge(use, jobj))
1361       continue; // No new edge added, there was such edge already.
1362     new_edges++;
1363     if (use->is_LocalVar()) {
1364       add_uses_to_worklist(use);
1365       if (use->arraycopy_dst()) {
1366         for (EdgeIterator i(use); i.has_next(); i.next()) {
1367           PointsToNode* e = i.get();
1368           if (e->is_Arraycopy()) {
1369             if (jobj == null_obj) // NULL object does not have field edges
1370               continue;
1371             // Add edge from arraycopy's destination java object to Arraycopy node.
1372             if (add_edge(jobj, e)) {
1373               new_edges++;
1374               jobj->set_arraycopy_dst();
1375             }
1376           }
1377         }
1378       }
1379     } else {
1380       // Added new edge to stored in field values.
1381       // Put on worklist all field's uses (loads) and
1382       // related field nodes (same base and offset).
1383       add_field_uses_to_worklist(use->as_Field());
1384     }
1385   }
1386   _worklist.clear();
1387   _in_worklist.Reset();
1388   return new_edges;
1389 }
1390 
1391 // Put on worklist all related field nodes.
1392 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
1393   assert(field->is_oop(), "sanity");
1394   int offset = field->offset();
1395   add_uses_to_worklist(field);
1396   // Loop over all bases of this field and push on worklist Field nodes
1397   // with the same offset and base (since they may reference the same field).
1398   for (BaseIterator i(field); i.has_next(); i.next()) {
1399     PointsToNode* base = i.get();
1400     add_fields_to_worklist(field, base);
1401     // Check if the base was source object of arraycopy and go over arraycopy's
1402     // destination objects since values stored to a field of source object are
1403     // accessable by uses (loads) of fields of destination objects.
1404     if (base->arraycopy_src()) {
1405       for (UseIterator j(base); j.has_next(); j.next()) {
1406         PointsToNode* arycp = j.get();
1407         if (arycp->is_Arraycopy()) {
1408           for (UseIterator k(arycp); k.has_next(); k.next()) {
1409             PointsToNode* abase = k.get();
1410             if (abase->arraycopy_dst() && abase != base) {
1411               // Look for the same arraycopy reference.
1412               add_fields_to_worklist(field, abase);
1413             }
1414           }
1415         }
1416       }
1417     }
1418   }
1419 }
1420 
1421 // Put on worklist all related field nodes.
1422 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
1423   int offset = field->offset();
1424   if (base->is_LocalVar()) {
1425     for (UseIterator j(base); j.has_next(); j.next()) {
1426       PointsToNode* f = j.get();
1427       if (PointsToNode::is_base_use(f)) { // Field
1428         f = PointsToNode::get_use_node(f);
1429         if (f == field || !f->as_Field()->is_oop())
1430           continue;
1431         int offs = f->as_Field()->offset();
1432         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1433           add_to_worklist(f);
1434         }
1435       }
1436     }
1437   } else {
1438     assert(base->is_JavaObject(), "sanity");
1439     if (// Skip phantom_object since it is only used to indicate that
1440         // this field's content globally escapes.
1441         (base != phantom_obj) &&
1442         // NULL object node does not have fields.
1443         (base != null_obj)) {
1444       for (EdgeIterator i(base); i.has_next(); i.next()) {
1445         PointsToNode* f = i.get();
1446         // Skip arraycopy edge since store to destination object field
1447         // does not update value in source object field.
1448         if (f->is_Arraycopy()) {
1449           assert(base->arraycopy_dst(), "sanity");
1450           continue;
1451         }
1452         if (f == field || !f->as_Field()->is_oop())
1453           continue;
1454         int offs = f->as_Field()->offset();
1455         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1456           add_to_worklist(f);
1457         }
1458       }
1459     }
1460   }
1461 }
1462 
1463 // Find fields which have unknown value.
1464 int ConnectionGraph::find_field_value(FieldNode* field) {
1465   // Escaped fields should have init value already.
1466   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
1467   int new_edges = 0;
1468   for (BaseIterator i(field); i.has_next(); i.next()) {
1469     PointsToNode* base = i.get();
1470     if (base->is_JavaObject()) {
1471       // Skip Allocate's fields which will be processed later.
1472       if (base->ideal_node()->is_Allocate())
1473         return 0;
1474       assert(base == null_obj, "only NULL ptr base expected here");
1475     }
1476   }
1477   if (add_edge(field, phantom_obj)) {
1478     // New edge was added
1479     new_edges++;
1480     add_field_uses_to_worklist(field);
1481   }
1482   return new_edges;
1483 }
1484 
1485 // Find fields initializing values for allocations.
1486 int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
1487   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
1488   int new_edges = 0;
1489   Node* alloc = pta->ideal_node();
1490   if (init_val == phantom_obj) {
1491     // Do nothing for Allocate nodes since its fields values are
1492     // "known" unless they are initialized by arraycopy/clone.
1493     if (alloc->is_Allocate() && !pta->arraycopy_dst())
1494       return 0;
1495     assert(pta->arraycopy_dst() || alloc->as_CallStaticJava(), "sanity");
1496 #ifdef ASSERT
1497     if (!pta->arraycopy_dst() && alloc->as_CallStaticJava()->method() == NULL) {
1498       const char* name = alloc->as_CallStaticJava()->_name;
1499       assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
1500     }
1501 #endif
1502     // Non-escaped allocation returned from Java or runtime call have
1503     // unknown values in fields.
1504     for (EdgeIterator i(pta); i.has_next(); i.next()) {
1505       PointsToNode* field = i.get();
1506       if (field->is_Field() && field->as_Field()->is_oop()) {
1507         if (add_edge(field, phantom_obj)) {
1508           // New edge was added
1509           new_edges++;
1510           add_field_uses_to_worklist(field->as_Field());
1511         }
1512       }
1513     }
1514     return new_edges;
1515   }
1516   assert(init_val == null_obj, "sanity");
1517   // Do nothing for Call nodes since its fields values are unknown.
1518   if (!alloc->is_Allocate())
1519     return 0;
1520 
1521   InitializeNode* ini = alloc->as_Allocate()->initialization();
1522   bool visited_bottom_offset = false;
1523   GrowableArray<int> offsets_worklist;
1524 
1525   // Check if an oop field's initializing value is recorded and add
1526   // a corresponding NULL if field's value if it is not recorded.
1527   // Connection Graph does not record a default initialization by NULL
1528   // captured by Initialize node.
1529   //
1530   for (EdgeIterator i(pta); i.has_next(); i.next()) {
1531     PointsToNode* field = i.get(); // Field (AddP)
1532     if (!field->is_Field() || !field->as_Field()->is_oop())
1533       continue; // Not oop field
1534     int offset = field->as_Field()->offset();
1535     if (offset == Type::OffsetBot) {
1536       if (!visited_bottom_offset) {
1537         // OffsetBot is used to reference array's element,
1538         // always add reference to NULL to all Field nodes since we don't
1539         // known which element is referenced.
1540         if (add_edge(field, null_obj)) {
1541           // New edge was added
1542           new_edges++;
1543           add_field_uses_to_worklist(field->as_Field());
1544           visited_bottom_offset = true;
1545         }
1546       }
1547     } else {
1548       // Check only oop fields.
1549       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
1550       if (adr_type->isa_rawptr()) {
1551 #ifdef ASSERT
1552         // Raw pointers are used for initializing stores so skip it
1553         // since it should be recorded already
1554         Node* base = get_addp_base(field->ideal_node());
1555         assert(adr_type->isa_rawptr() && base->is_Proj() &&
1556                (base->in(0) == alloc),"unexpected pointer type");
1557 #endif
1558         continue;
1559       }
1560       if (!offsets_worklist.contains(offset)) {
1561         offsets_worklist.append(offset);
1562         Node* value = NULL;
1563         if (ini != NULL) {
1564           // StoreP::memory_type() == T_ADDRESS
1565           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
1566           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
1567           // Make sure initializing store has the same type as this AddP.
1568           // This AddP may reference non existing field because it is on a
1569           // dead branch of bimorphic call which is not eliminated yet.
1570           if (store != NULL && store->is_Store() &&
1571               store->as_Store()->memory_type() == ft) {
1572             value = store->in(MemNode::ValueIn);
1573 #ifdef ASSERT
1574             if (VerifyConnectionGraph) {
1575               // Verify that AddP already points to all objects the value points to.
1576               PointsToNode* val = ptnode_adr(value->_idx);
1577               assert((val != NULL), "should be processed already");
1578               PointsToNode* missed_obj = NULL;
1579               if (val->is_JavaObject()) {
1580                 if (!field->points_to(val->as_JavaObject())) {
1581                   missed_obj = val;
1582                 }
1583               } else {
1584                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
1585                   tty->print_cr("----------init store has invalid value -----");
1586                   store->dump();
1587                   val->dump();
1588                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
1589                 }
1590                 for (EdgeIterator j(val); j.has_next(); j.next()) {
1591                   PointsToNode* obj = j.get();
1592                   if (obj->is_JavaObject()) {
1593                     if (!field->points_to(obj->as_JavaObject())) {
1594                       missed_obj = obj;
1595                       break;
1596                     }
1597                   }
1598                 }
1599               }
1600               if (missed_obj != NULL) {
1601                 tty->print_cr("----------field---------------------------------");
1602                 field->dump();
1603                 tty->print_cr("----------missed referernce to object-----------");
1604                 missed_obj->dump();
1605                 tty->print_cr("----------object referernced by init store -----");
1606                 store->dump();
1607                 val->dump();
1608                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
1609               }
1610             }
1611 #endif
1612           } else {
1613             // There could be initializing stores which follow allocation.
1614             // For example, a volatile field store is not collected
1615             // by Initialize node.
1616             //
1617             // Need to check for dependent loads to separate such stores from
1618             // stores which follow loads. For now, add initial value NULL so
1619             // that compare pointers optimization works correctly.
1620           }
1621         }
1622         if (value == NULL) {
1623           // A field's initializing value was not recorded. Add NULL.
1624           if (add_edge(field, null_obj)) {
1625             // New edge was added
1626             new_edges++;
1627             add_field_uses_to_worklist(field->as_Field());
1628           }
1629         }
1630       }
1631     }
1632   }
1633   return new_edges;
1634 }
1635 
1636 // Adjust scalar_replaceable state after Connection Graph is built.
1637 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
1638   // Search for non-escaping objects which are not scalar replaceable
1639   // and mark them to propagate the state to referenced objects.
1640 
1641   // 1. An object is not scalar replaceable if the field into which it is
1642   // stored has unknown offset (stored into unknown element of an array).
1643   //
1644   for (UseIterator i(jobj); i.has_next(); i.next()) {
1645     PointsToNode* use = i.get();
1646     if (use->is_Arraycopy()) {
1647       continue;
1648     }
1649     if (use->is_Field()) {
1650       FieldNode* field = use->as_Field();
1651       assert(field->is_oop() && field->scalar_replaceable(), "sanity");
1652       if (field->offset() == Type::OffsetBot) {
1653         jobj->set_scalar_replaceable(false);
1654         return;
1655       }
1656       // 2. An object is not scalar replaceable if the field into which it is
1657       // stored has multiple bases one of which is null.
1658       if (field->base_count() > 1) {
1659         for (BaseIterator i(field); i.has_next(); i.next()) {
1660           PointsToNode* base = i.get();
1661           if (base == null_obj) {
1662             jobj->set_scalar_replaceable(false);
1663             return;
1664           }
1665         }
1666       }
1667     }
1668     assert(use->is_Field() || use->is_LocalVar(), "sanity");
1669     // 3. An object is not scalar replaceable if it is merged with other objects.
1670     for (EdgeIterator j(use); j.has_next(); j.next()) {
1671       PointsToNode* ptn = j.get();
1672       if (ptn->is_JavaObject() && ptn != jobj) {
1673         // Mark all objects.
1674         jobj->set_scalar_replaceable(false);
1675          ptn->set_scalar_replaceable(false);
1676       }
1677     }
1678     if (!jobj->scalar_replaceable()) {
1679       return;
1680     }
1681   }
1682 
1683   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
1684     if (j.get()->is_Arraycopy()) {
1685       continue;
1686     }
1687 
1688     // Non-escaping object node should point only to field nodes.
1689     FieldNode* field = j.get()->as_Field();
1690     int offset = field->as_Field()->offset();
1691 
1692     // 4. An object is not scalar replaceable if it has a field with unknown
1693     // offset (array's element is accessed in loop).
1694     if (offset == Type::OffsetBot) {
1695       jobj->set_scalar_replaceable(false);
1696       return;
1697     }
1698     // 5. Currently an object is not scalar replaceable if a LoadStore node
1699     // access its field since the field value is unknown after it.
1700     //
1701     Node* n = field->ideal_node();
1702     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1703       if (n->fast_out(i)->is_LoadStore()) {
1704         jobj->set_scalar_replaceable(false);
1705         return;
1706       }
1707     }
1708 
1709     // 6. Or the address may point to more then one object. This may produce
1710     // the false positive result (set not scalar replaceable)
1711     // since the flow-insensitive escape analysis can't separate
1712     // the case when stores overwrite the field's value from the case
1713     // when stores happened on different control branches.
1714     //
1715     // Note: it will disable scalar replacement in some cases:
1716     //
1717     //    Point p[] = new Point[1];
1718     //    p[0] = new Point(); // Will be not scalar replaced
1719     //
1720     // but it will save us from incorrect optimizations in next cases:
1721     //
1722     //    Point p[] = new Point[1];
1723     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
1724     //
1725     if (field->base_count() > 1) {
1726       for (BaseIterator i(field); i.has_next(); i.next()) {
1727         PointsToNode* base = i.get();
1728         // Don't take into account LocalVar nodes which
1729         // may point to only one object which should be also
1730         // this field's base by now.
1731         if (base->is_JavaObject() && base != jobj) {
1732           // Mark all bases.
1733           jobj->set_scalar_replaceable(false);
1734           base->set_scalar_replaceable(false);
1735         }
1736       }
1737     }
1738   }
1739 }
1740 
1741 #ifdef ASSERT
1742 void ConnectionGraph::verify_connection_graph(
1743                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1744                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1745                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1746                          GrowableArray<Node*>& addp_worklist) {
1747   // Verify that graph is complete - no new edges could be added.
1748   int java_objects_length = java_objects_worklist.length();
1749   int non_escaped_length  = non_escaped_worklist.length();
1750   int new_edges = 0;
1751   for (int next = 0; next < java_objects_length; ++next) {
1752     JavaObjectNode* ptn = java_objects_worklist.at(next);
1753     new_edges += add_java_object_edges(ptn, true);
1754   }
1755   assert(new_edges == 0, "graph was not complete");
1756   // Verify that escape state is final.
1757   int length = non_escaped_worklist.length();
1758   find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
1759   assert((non_escaped_length == non_escaped_worklist.length()) &&
1760          (non_escaped_length == length) &&
1761          (_worklist.length() == 0), "escape state was not final");
1762 
1763   // Verify fields information.
1764   int addp_length = addp_worklist.length();
1765   for (int next = 0; next < addp_length; ++next ) {
1766     Node* n = addp_worklist.at(next);
1767     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
1768     if (field->is_oop()) {
1769       // Verify that field has all bases
1770       Node* base = get_addp_base(n);
1771       PointsToNode* ptn = ptnode_adr(base->_idx);
1772       if (ptn->is_JavaObject()) {
1773         assert(field->has_base(ptn->as_JavaObject()), "sanity");
1774       } else {
1775         assert(ptn->is_LocalVar(), "sanity");
1776         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1777           PointsToNode* e = i.get();
1778           if (e->is_JavaObject()) {
1779             assert(field->has_base(e->as_JavaObject()), "sanity");
1780           }
1781         }
1782       }
1783       // Verify that all fields have initializing values.
1784       if (field->edge_count() == 0) {
1785         tty->print_cr("----------field does not have references----------");
1786         field->dump();
1787         for (BaseIterator i(field); i.has_next(); i.next()) {
1788           PointsToNode* base = i.get();
1789           tty->print_cr("----------field has next base---------------------");
1790           base->dump();
1791           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
1792             tty->print_cr("----------base has fields-------------------------");
1793             for (EdgeIterator j(base); j.has_next(); j.next()) {
1794               j.get()->dump();
1795             }
1796             tty->print_cr("----------base has references---------------------");
1797             for (UseIterator j(base); j.has_next(); j.next()) {
1798               j.get()->dump();
1799             }
1800           }
1801         }
1802         for (UseIterator i(field); i.has_next(); i.next()) {
1803           i.get()->dump();
1804         }
1805         assert(field->edge_count() > 0, "sanity");
1806       }
1807     }
1808   }
1809 }
1810 #endif
1811 
1812 // Optimize ideal graph.
1813 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
1814                                            GrowableArray<Node*>& storestore_worklist) {
1815   Compile* C = _compile;
1816   PhaseIterGVN* igvn = _igvn;
1817   if (EliminateLocks) {
1818     // Mark locks before changing ideal graph.
1819     int cnt = C->macro_count();
1820     for( int i=0; i < cnt; i++ ) {
1821       Node *n = C->macro_node(i);
1822       if (n->is_AbstractLock()) { // Lock and Unlock nodes
1823         AbstractLockNode* alock = n->as_AbstractLock();
1824         if (!alock->is_non_esc_obj()) {
1825           if (not_global_escape(alock->obj_node())) {
1826             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
1827             // The lock could be marked eliminated by lock coarsening
1828             // code during first IGVN before EA. Replace coarsened flag
1829             // to eliminate all associated locks/unlocks.
1830 #ifdef ASSERT
1831             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
1832 #endif
1833             alock->set_non_esc_obj();
1834           }
1835         }
1836       }
1837     }
1838   }
1839 
1840   if (OptimizePtrCompare) {
1841     // Add ConI(#CC_GT) and ConI(#CC_EQ).
1842     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);
1843     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
1844     // Optimize objects compare.
1845     while (ptr_cmp_worklist.length() != 0) {
1846       Node *n = ptr_cmp_worklist.pop();
1847       Node *res = optimize_ptr_compare(n);
1848       if (res != NULL) {
1849 #ifndef PRODUCT
1850         if (PrintOptimizePtrCompare) {
1851           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"));
1852           if (Verbose) {
1853             n->dump(1);
1854           }
1855         }
1856 #endif
1857         igvn->replace_node(n, res);
1858       }
1859     }
1860     // cleanup
1861     if (_pcmp_neq->outcnt() == 0)
1862       igvn->hash_delete(_pcmp_neq);
1863     if (_pcmp_eq->outcnt()  == 0)
1864       igvn->hash_delete(_pcmp_eq);
1865   }
1866 
1867   // For MemBarStoreStore nodes added in library_call.cpp, check
1868   // escape status of associated AllocateNode and optimize out
1869   // MemBarStoreStore node if the allocated object never escapes.
1870   while (storestore_worklist.length() != 0) {
1871     Node *n = storestore_worklist.pop();
1872     MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
1873     Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
1874     assert (alloc->is_Allocate(), "storestore should point to AllocateNode");
1875     if (not_global_escape(alloc)) {
1876       MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
1877       mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
1878       mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
1879       igvn->register_new_node_with_optimizer(mb);
1880       igvn->replace_node(storestore, mb);
1881     }
1882   }
1883 }
1884 
1885 // Optimize objects compare.
1886 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
1887   assert(OptimizePtrCompare, "sanity");
1888   PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
1889   PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
1890   JavaObjectNode* jobj1 = unique_java_object(n->in(1));
1891   JavaObjectNode* jobj2 = unique_java_object(n->in(2));
1892   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
1893   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
1894 
1895   // Check simple cases first.
1896   if (jobj1 != NULL) {
1897     if (jobj1->escape_state() == PointsToNode::NoEscape) {
1898       if (jobj1 == jobj2) {
1899         // Comparing the same not escaping object.
1900         return _pcmp_eq;
1901       }
1902       Node* obj = jobj1->ideal_node();
1903       // Comparing not escaping allocation.
1904       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1905           !ptn2->points_to(jobj1)) {
1906         return _pcmp_neq; // This includes nullness check.
1907       }
1908     }
1909   }
1910   if (jobj2 != NULL) {
1911     if (jobj2->escape_state() == PointsToNode::NoEscape) {
1912       Node* obj = jobj2->ideal_node();
1913       // Comparing not escaping allocation.
1914       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1915           !ptn1->points_to(jobj2)) {
1916         return _pcmp_neq; // This includes nullness check.
1917       }
1918     }
1919   }
1920   if (jobj1 != NULL && jobj1 != phantom_obj &&
1921       jobj2 != NULL && jobj2 != phantom_obj &&
1922       jobj1->ideal_node()->is_Con() &&
1923       jobj2->ideal_node()->is_Con()) {
1924     // Klass or String constants compare. Need to be careful with
1925     // compressed pointers - compare types of ConN and ConP instead of nodes.
1926     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
1927     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
1928     if (t1->make_ptr() == t2->make_ptr()) {
1929       return _pcmp_eq;
1930     } else {
1931       return _pcmp_neq;
1932     }
1933   }
1934   if (ptn1->meet(ptn2)) {
1935     return NULL; // Sets are not disjoint
1936   }
1937 
1938   // Sets are disjoint.
1939   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
1940   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
1941   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
1942   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
1943   if (set1_has_unknown_ptr && set2_has_null_ptr ||
1944       set2_has_unknown_ptr && set1_has_null_ptr) {
1945     // Check nullness of unknown object.
1946     return NULL;
1947   }
1948 
1949   // Disjointness by itself is not sufficient since
1950   // alias analysis is not complete for escaped objects.
1951   // Disjoint sets are definitely unrelated only when
1952   // at least one set has only not escaping allocations.
1953   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
1954     if (ptn1->non_escaping_allocation()) {
1955       return _pcmp_neq;
1956     }
1957   }
1958   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
1959     if (ptn2->non_escaping_allocation()) {
1960       return _pcmp_neq;
1961     }
1962   }
1963   return NULL;
1964 }
1965 
1966 // Connection Graph constuction functions.
1967 
1968 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
1969   PointsToNode* ptadr = _nodes.at(n->_idx);
1970   if (ptadr != NULL) {
1971     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
1972     return;
1973   }
1974   Compile* C = _compile;
1975   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
1976   _nodes.at_put(n->_idx, ptadr);
1977 }
1978 
1979 void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
1980   PointsToNode* ptadr = _nodes.at(n->_idx);
1981   if (ptadr != NULL) {
1982     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
1983     return;
1984   }
1985   Compile* C = _compile;
1986   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
1987   _nodes.at_put(n->_idx, ptadr);
1988 }
1989 
1990 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
1991   PointsToNode* ptadr = _nodes.at(n->_idx);
1992   if (ptadr != NULL) {
1993     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
1994     return;
1995   }
1996   bool unsafe = false;
1997   bool is_oop = is_oop_field(n, offset, &unsafe);
1998   if (unsafe) {
1999     es = PointsToNode::GlobalEscape;
2000   }
2001   Compile* C = _compile;
2002   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
2003   _nodes.at_put(n->_idx, field);
2004 }
2005 
2006 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
2007                                     PointsToNode* src, PointsToNode* dst) {
2008   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
2009   assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
2010   PointsToNode* ptadr = _nodes.at(n->_idx);
2011   if (ptadr != NULL) {
2012     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
2013     return;
2014   }
2015   Compile* C = _compile;
2016   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
2017   _nodes.at_put(n->_idx, ptadr);
2018   // Add edge from arraycopy node to source object.
2019   (void)add_edge(ptadr, src);
2020   src->set_arraycopy_src();
2021   // Add edge from destination object to arraycopy node.
2022   (void)add_edge(dst, ptadr);
2023   dst->set_arraycopy_dst();
2024 }
2025 
2026 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
2027   const Type* adr_type = n->as_AddP()->bottom_type();
2028   BasicType bt = T_INT;
2029   if (offset == Type::OffsetBot) {
2030     // Check only oop fields.
2031     if (!adr_type->isa_aryptr() ||
2032         (adr_type->isa_aryptr()->klass() == NULL) ||
2033          adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
2034       // OffsetBot is used to reference array's element. Ignore first AddP.
2035       if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
2036         bt = T_OBJECT;
2037       }
2038     }
2039   } else if (offset != oopDesc::klass_offset_in_bytes()) {
2040     if (adr_type->isa_instptr()) {
2041       ciField* field = _compile->alias_type(adr_type->isa_instptr())->field();
2042       if (field != NULL) {
2043         bt = field->layout_type();
2044       } else {
2045         // Check for unsafe oop field access
2046         if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
2047           bt = T_OBJECT;
2048           (*unsafe) = true;
2049         }
2050       }
2051     } else if (adr_type->isa_aryptr()) {
2052       if (offset == arrayOopDesc::length_offset_in_bytes()) {
2053         // Ignore array length load.
2054       } else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
2055         // Ignore first AddP.
2056       } else {
2057         const Type* elemtype = adr_type->isa_aryptr()->elem();
2058         bt = elemtype->array_element_basic_type();
2059       }
2060     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
2061       // Allocation initialization, ThreadLocal field access, unsafe access
2062       if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
2063         bt = T_OBJECT;
2064       }
2065     }
2066   }
2067   return (bt == T_OBJECT || bt == T_NARROWOOP || bt == T_ARRAY);
2068 }
2069 
2070 // Returns unique pointed java object or NULL.
2071 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
2072   assert(!_collecting, "should not call when contructed graph");
2073   // If the node was created after the escape computation we can't answer.
2074   uint idx = n->_idx;
2075   if (idx >= nodes_size()) {
2076     return NULL;
2077   }
2078   PointsToNode* ptn = ptnode_adr(idx);
2079   if (ptn->is_JavaObject()) {
2080     return ptn->as_JavaObject();
2081   }
2082   assert(ptn->is_LocalVar(), "sanity");
2083   // Check all java objects it points to.
2084   JavaObjectNode* jobj = NULL;
2085   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2086     PointsToNode* e = i.get();
2087     if (e->is_JavaObject()) {
2088       if (jobj == NULL) {
2089         jobj = e->as_JavaObject();
2090       } else if (jobj != e) {
2091         return NULL;
2092       }
2093     }
2094   }
2095   return jobj;
2096 }
2097 
2098 // Return true if this node points only to non-escaping allocations.
2099 bool PointsToNode::non_escaping_allocation() {
2100   if (is_JavaObject()) {
2101     Node* n = ideal_node();
2102     if (n->is_Allocate() || n->is_CallStaticJava()) {
2103       return (escape_state() == PointsToNode::NoEscape);
2104     } else {
2105       return false;
2106     }
2107   }
2108   assert(is_LocalVar(), "sanity");
2109   // Check all java objects it points to.
2110   for (EdgeIterator i(this); i.has_next(); i.next()) {
2111     PointsToNode* e = i.get();
2112     if (e->is_JavaObject()) {
2113       Node* n = e->ideal_node();
2114       if ((e->escape_state() != PointsToNode::NoEscape) ||
2115           !(n->is_Allocate() || n->is_CallStaticJava())) {
2116         return false;
2117       }
2118     }
2119   }
2120   return true;
2121 }
2122 
2123 // Return true if we know the node does not escape globally.
2124 bool ConnectionGraph::not_global_escape(Node *n) {
2125   assert(!_collecting, "should not call during graph construction");
2126   // If the node was created after the escape computation we can't answer.
2127   uint idx = n->_idx;
2128   if (idx >= nodes_size()) {
2129     return false;
2130   }
2131   PointsToNode* ptn = ptnode_adr(idx);
2132   PointsToNode::EscapeState es = ptn->escape_state();
2133   // If we have already computed a value, return it.
2134   if (es >= PointsToNode::GlobalEscape)
2135     return false;
2136   if (ptn->is_JavaObject()) {
2137     return true; // (es < PointsToNode::GlobalEscape);
2138   }
2139   assert(ptn->is_LocalVar(), "sanity");
2140   // Check all java objects it points to.
2141   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2142     if (i.get()->escape_state() >= PointsToNode::GlobalEscape)
2143       return false;
2144   }
2145   return true;
2146 }
2147 
2148 
2149 // Helper functions
2150 
2151 // Return true if this node points to specified node or nodes it points to.
2152 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
2153   if (is_JavaObject()) {
2154     return (this == ptn);
2155   }
2156   assert(is_LocalVar() || is_Field(), "sanity");
2157   for (EdgeIterator i(this); i.has_next(); i.next()) {
2158     if (i.get() == ptn)
2159       return true;
2160   }
2161   return false;
2162 }
2163 
2164 // Return true if one node points to an other.
2165 bool PointsToNode::meet(PointsToNode* ptn) {
2166   if (this == ptn) {
2167     return true;
2168   } else if (ptn->is_JavaObject()) {
2169     return this->points_to(ptn->as_JavaObject());
2170   } else if (this->is_JavaObject()) {
2171     return ptn->points_to(this->as_JavaObject());
2172   }
2173   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
2174   int ptn_count =  ptn->edge_count();
2175   for (EdgeIterator i(this); i.has_next(); i.next()) {
2176     PointsToNode* this_e = i.get();
2177     for (int j = 0; j < ptn_count; j++) {
2178       if (this_e == ptn->edge(j))
2179         return true;
2180     }
2181   }
2182   return false;
2183 }
2184 
2185 #ifdef ASSERT
2186 // Return true if bases point to this java object.
2187 bool FieldNode::has_base(JavaObjectNode* jobj) const {
2188   for (BaseIterator i(this); i.has_next(); i.next()) {
2189     if (i.get() == jobj)
2190       return true;
2191   }
2192   return false;
2193 }
2194 #endif
2195 
2196 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
2197   const Type *adr_type = phase->type(adr);
2198   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
2199       adr->in(AddPNode::Address)->is_Proj() &&
2200       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
2201     // We are computing a raw address for a store captured by an Initialize
2202     // compute an appropriate address type. AddP cases #3 and #5 (see below).
2203     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
2204     assert(offs != Type::OffsetBot ||
2205            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
2206            "offset must be a constant or it is initialization of array");
2207     return offs;
2208   }
2209   const TypePtr *t_ptr = adr_type->isa_ptr();
2210   assert(t_ptr != NULL, "must be a pointer type");
2211   return t_ptr->offset();
2212 }
2213 
2214 Node* ConnectionGraph::get_addp_base(Node *addp) {
2215   assert(addp->is_AddP(), "must be AddP");
2216   //
2217   // AddP cases for Base and Address inputs:
2218   // case #1. Direct object's field reference:
2219   //     Allocate
2220   //       |
2221   //     Proj #5 ( oop result )
2222   //       |
2223   //     CheckCastPP (cast to instance type)
2224   //      | |
2225   //     AddP  ( base == address )
2226   //
2227   // case #2. Indirect object's field reference:
2228   //      Phi
2229   //       |
2230   //     CastPP (cast to instance type)
2231   //      | |
2232   //     AddP  ( base == address )
2233   //
2234   // case #3. Raw object's field reference for Initialize node:
2235   //      Allocate
2236   //        |
2237   //      Proj #5 ( oop result )
2238   //  top   |
2239   //     \  |
2240   //     AddP  ( base == top )
2241   //
2242   // case #4. Array's element reference:
2243   //   {CheckCastPP | CastPP}
2244   //     |  | |
2245   //     |  AddP ( array's element offset )
2246   //     |  |
2247   //     AddP ( array's offset )
2248   //
2249   // case #5. Raw object's field reference for arraycopy stub call:
2250   //          The inline_native_clone() case when the arraycopy stub is called
2251   //          after the allocation before Initialize and CheckCastPP nodes.
2252   //      Allocate
2253   //        |
2254   //      Proj #5 ( oop result )
2255   //       | |
2256   //       AddP  ( base == address )
2257   //
2258   // case #6. Constant Pool, ThreadLocal, CastX2P or
2259   //          Raw object's field reference:
2260   //      {ConP, ThreadLocal, CastX2P, raw Load}
2261   //  top   |
2262   //     \  |
2263   //     AddP  ( base == top )
2264   //
2265   // case #7. Klass's field reference.
2266   //      LoadKlass
2267   //       | |
2268   //       AddP  ( base == address )
2269   //
2270   // case #8. narrow Klass's field reference.
2271   //      LoadNKlass
2272   //       |
2273   //      DecodeN
2274   //       | |
2275   //       AddP  ( base == address )
2276   //
2277   Node *base = addp->in(AddPNode::Base);
2278   if (base->uncast()->is_top()) { // The AddP case #3 and #6.
2279     base = addp->in(AddPNode::Address);
2280     while (base->is_AddP()) {
2281       // Case #6 (unsafe access) may have several chained AddP nodes.
2282       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
2283       base = base->in(AddPNode::Address);
2284     }
2285     Node* uncast_base = base->uncast();
2286     int opcode = uncast_base->Opcode();
2287     assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
2288            opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
2289            (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
2290            (uncast_base->is_Proj() && uncast_base->in(0)->is_Allocate()), "sanity");
2291   }
2292   return base;
2293 }
2294 
2295 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
2296   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
2297   Node* addp2 = addp->raw_out(0);
2298   if (addp->outcnt() == 1 && addp2->is_AddP() &&
2299       addp2->in(AddPNode::Base) == n &&
2300       addp2->in(AddPNode::Address) == addp) {
2301     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
2302     //
2303     // Find array's offset to push it on worklist first and
2304     // as result process an array's element offset first (pushed second)
2305     // to avoid CastPP for the array's offset.
2306     // Otherwise the inserted CastPP (LocalVar) will point to what
2307     // the AddP (Field) points to. Which would be wrong since
2308     // the algorithm expects the CastPP has the same point as
2309     // as AddP's base CheckCastPP (LocalVar).
2310     //
2311     //    ArrayAllocation
2312     //     |
2313     //    CheckCastPP
2314     //     |
2315     //    memProj (from ArrayAllocation CheckCastPP)
2316     //     |  ||
2317     //     |  ||   Int (element index)
2318     //     |  ||    |   ConI (log(element size))
2319     //     |  ||    |   /
2320     //     |  ||   LShift
2321     //     |  ||  /
2322     //     |  AddP (array's element offset)
2323     //     |  |
2324     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
2325     //     | / /
2326     //     AddP (array's offset)
2327     //      |
2328     //     Load/Store (memory operation on array's element)
2329     //
2330     return addp2;
2331   }
2332   return NULL;
2333 }
2334 
2335 //
2336 // Adjust the type and inputs of an AddP which computes the
2337 // address of a field of an instance
2338 //
2339 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
2340   PhaseGVN* igvn = _igvn;
2341   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
2342   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
2343   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
2344   if (t == NULL) {
2345     // We are computing a raw address for a store captured by an Initialize
2346     // compute an appropriate address type (cases #3 and #5).
2347     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
2348     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
2349     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
2350     assert(offs != Type::OffsetBot, "offset must be a constant");
2351     t = base_t->add_offset(offs)->is_oopptr();
2352   }
2353   int inst_id =  base_t->instance_id();
2354   assert(!t->is_known_instance() || t->instance_id() == inst_id,
2355                              "old type must be non-instance or match new type");
2356 
2357   // The type 't' could be subclass of 'base_t'.
2358   // As result t->offset() could be large then base_t's size and it will
2359   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
2360   // constructor verifies correctness of the offset.
2361   //
2362   // It could happened on subclass's branch (from the type profiling
2363   // inlining) which was not eliminated during parsing since the exactness
2364   // of the allocation type was not propagated to the subclass type check.
2365   //
2366   // Or the type 't' could be not related to 'base_t' at all.
2367   // It could happened when CHA type is different from MDO type on a dead path
2368   // (for example, from instanceof check) which is not collapsed during parsing.
2369   //
2370   // Do nothing for such AddP node and don't process its users since
2371   // this code branch will go away.
2372   //
2373   if (!t->is_known_instance() &&
2374       !base_t->klass()->is_subtype_of(t->klass())) {
2375      return false; // bail out
2376   }
2377   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
2378   // Do NOT remove the next line: ensure a new alias index is allocated
2379   // for the instance type. Note: C++ will not remove it since the call
2380   // has side effect.
2381   int alias_idx = _compile->get_alias_index(tinst);
2382   igvn->set_type(addp, tinst);
2383   // record the allocation in the node map
2384   set_map(addp, get_map(base->_idx));
2385   // Set addp's Base and Address to 'base'.
2386   Node *abase = addp->in(AddPNode::Base);
2387   Node *adr   = addp->in(AddPNode::Address);
2388   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
2389       adr->in(0)->_idx == (uint)inst_id) {
2390     // Skip AddP cases #3 and #5.
2391   } else {
2392     assert(!abase->is_top(), "sanity"); // AddP case #3
2393     if (abase != base) {
2394       igvn->hash_delete(addp);
2395       addp->set_req(AddPNode::Base, base);
2396       if (abase == adr) {
2397         addp->set_req(AddPNode::Address, base);
2398       } else {
2399         // AddP case #4 (adr is array's element offset AddP node)
2400 #ifdef ASSERT
2401         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
2402         assert(adr->is_AddP() && atype != NULL &&
2403                atype->instance_id() == inst_id, "array's element offset should be processed first");
2404 #endif
2405       }
2406       igvn->hash_insert(addp);
2407     }
2408   }
2409   // Put on IGVN worklist since at least addp's type was changed above.
2410   record_for_optimizer(addp);
2411   return true;
2412 }
2413 
2414 //
2415 // Create a new version of orig_phi if necessary. Returns either the newly
2416 // created phi or an existing phi.  Sets create_new to indicate whether a new
2417 // phi was created.  Cache the last newly created phi in the node map.
2418 //
2419 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
2420   Compile *C = _compile;
2421   PhaseGVN* igvn = _igvn;
2422   new_created = false;
2423   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
2424   // nothing to do if orig_phi is bottom memory or matches alias_idx
2425   if (phi_alias_idx == alias_idx) {
2426     return orig_phi;
2427   }
2428   // Have we recently created a Phi for this alias index?
2429   PhiNode *result = get_map_phi(orig_phi->_idx);
2430   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
2431     return result;
2432   }
2433   // Previous check may fail when the same wide memory Phi was split into Phis
2434   // for different memory slices. Search all Phis for this region.
2435   if (result != NULL) {
2436     Node* region = orig_phi->in(0);
2437     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
2438       Node* phi = region->fast_out(i);
2439       if (phi->is_Phi() &&
2440           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
2441         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
2442         return phi->as_Phi();
2443       }
2444     }
2445   }
2446   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
2447     if (C->do_escape_analysis() == true && !C->failing()) {
2448       // Retry compilation without escape analysis.
2449       // If this is the first failure, the sentinel string will "stick"
2450       // to the Compile object, and the C2Compiler will see it and retry.
2451       C->record_failure(C2Compiler::retry_no_escape_analysis());
2452     }
2453     return NULL;
2454   }
2455   orig_phi_worklist.append_if_missing(orig_phi);
2456   const TypePtr *atype = C->get_adr_type(alias_idx);
2457   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
2458   C->copy_node_notes_to(result, orig_phi);
2459   igvn->set_type(result, result->bottom_type());
2460   record_for_optimizer(result);
2461   set_map(orig_phi, result);
2462   new_created = true;
2463   return result;
2464 }
2465 
2466 //
2467 // Return a new version of Memory Phi "orig_phi" with the inputs having the
2468 // specified alias index.
2469 //
2470 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist) {
2471   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
2472   Compile *C = _compile;
2473   PhaseGVN* igvn = _igvn;
2474   bool new_phi_created;
2475   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
2476   if (!new_phi_created) {
2477     return result;
2478   }
2479   GrowableArray<PhiNode *>  phi_list;
2480   GrowableArray<uint>  cur_input;
2481   PhiNode *phi = orig_phi;
2482   uint idx = 1;
2483   bool finished = false;
2484   while(!finished) {
2485     while (idx < phi->req()) {
2486       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist);
2487       if (mem != NULL && mem->is_Phi()) {
2488         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
2489         if (new_phi_created) {
2490           // found an phi for which we created a new split, push current one on worklist and begin
2491           // processing new one
2492           phi_list.push(phi);
2493           cur_input.push(idx);
2494           phi = mem->as_Phi();
2495           result = newphi;
2496           idx = 1;
2497           continue;
2498         } else {
2499           mem = newphi;
2500         }
2501       }
2502       if (C->failing()) {
2503         return NULL;
2504       }
2505       result->set_req(idx++, mem);
2506     }
2507 #ifdef ASSERT
2508     // verify that the new Phi has an input for each input of the original
2509     assert( phi->req() == result->req(), "must have same number of inputs.");
2510     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
2511 #endif
2512     // Check if all new phi's inputs have specified alias index.
2513     // Otherwise use old phi.
2514     for (uint i = 1; i < phi->req(); i++) {
2515       Node* in = result->in(i);
2516       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
2517     }
2518     // we have finished processing a Phi, see if there are any more to do
2519     finished = (phi_list.length() == 0 );
2520     if (!finished) {
2521       phi = phi_list.pop();
2522       idx = cur_input.pop();
2523       PhiNode *prev_result = get_map_phi(phi->_idx);
2524       prev_result->set_req(idx++, result);
2525       result = prev_result;
2526     }
2527   }
2528   return result;
2529 }
2530 
2531 //
2532 // The next methods are derived from methods in MemNode.
2533 //
2534 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
2535   Node *mem = mmem;
2536   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
2537   // means an array I have not precisely typed yet.  Do not do any
2538   // alias stuff with it any time soon.
2539   if (toop->base() != Type::AnyPtr &&
2540       !(toop->klass() != NULL &&
2541         toop->klass()->is_java_lang_Object() &&
2542         toop->offset() == Type::OffsetBot)) {
2543     mem = mmem->memory_at(alias_idx);
2544     // Update input if it is progress over what we have now
2545   }
2546   return mem;
2547 }
2548 
2549 //
2550 // Move memory users to their memory slices.
2551 //
2552 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
2553   Compile* C = _compile;
2554   PhaseGVN* igvn = _igvn;
2555   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
2556   assert(tp != NULL, "ptr type");
2557   int alias_idx = C->get_alias_index(tp);
2558   int general_idx = C->get_general_index(alias_idx);
2559 
2560   // Move users first
2561   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2562     Node* use = n->fast_out(i);
2563     if (use->is_MergeMem()) {
2564       MergeMemNode* mmem = use->as_MergeMem();
2565       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
2566       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
2567         continue; // Nothing to do
2568       }
2569       // Replace previous general reference to mem node.
2570       uint orig_uniq = C->unique();
2571       Node* m = find_inst_mem(n, general_idx, orig_phis);
2572       assert(orig_uniq == C->unique(), "no new nodes");
2573       mmem->set_memory_at(general_idx, m);
2574       --imax;
2575       --i;
2576     } else if (use->is_MemBar()) {
2577       assert(!use->is_Initialize(), "initializing stores should not be moved");
2578       if (use->req() > MemBarNode::Precedent &&
2579           use->in(MemBarNode::Precedent) == n) {
2580         // Don't move related membars.
2581         record_for_optimizer(use);
2582         continue;
2583       }
2584       tp = use->as_MemBar()->adr_type()->isa_ptr();
2585       if (tp != NULL && C->get_alias_index(tp) == alias_idx ||
2586           alias_idx == general_idx) {
2587         continue; // Nothing to do
2588       }
2589       // Move to general memory slice.
2590       uint orig_uniq = C->unique();
2591       Node* m = find_inst_mem(n, general_idx, orig_phis);
2592       assert(orig_uniq == C->unique(), "no new nodes");
2593       igvn->hash_delete(use);
2594       imax -= use->replace_edge(n, m);
2595       igvn->hash_insert(use);
2596       record_for_optimizer(use);
2597       --i;
2598 #ifdef ASSERT
2599     } else if (use->is_Mem()) {
2600       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
2601         // Don't move related cardmark.
2602         continue;
2603       }
2604       // Memory nodes should have new memory input.
2605       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
2606       assert(tp != NULL, "ptr type");
2607       int idx = C->get_alias_index(tp);
2608       assert(get_map(use->_idx) != NULL || idx == alias_idx,
2609              "Following memory nodes should have new memory input or be on the same memory slice");
2610     } else if (use->is_Phi()) {
2611       // Phi nodes should be split and moved already.
2612       tp = use->as_Phi()->adr_type()->isa_ptr();
2613       assert(tp != NULL, "ptr type");
2614       int idx = C->get_alias_index(tp);
2615       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
2616     } else {
2617       use->dump();
2618       assert(false, "should not be here");
2619 #endif
2620     }
2621   }
2622 }
2623 
2624 //
2625 // Search memory chain of "mem" to find a MemNode whose address
2626 // is the specified alias index.
2627 //
2628 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis) {
2629   if (orig_mem == NULL)
2630     return orig_mem;
2631   Compile* C = _compile;
2632   PhaseGVN* igvn = _igvn;
2633   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
2634   bool is_instance = (toop != NULL) && toop->is_known_instance();
2635   Node *start_mem = C->start()->proj_out(TypeFunc::Memory);
2636   Node *prev = NULL;
2637   Node *result = orig_mem;
2638   while (prev != result) {
2639     prev = result;
2640     if (result == start_mem)
2641       break;  // hit one of our sentinels
2642     if (result->is_Mem()) {
2643       const Type *at = igvn->type(result->in(MemNode::Address));
2644       if (at == Type::TOP)
2645         break; // Dead
2646       assert (at->isa_ptr() != NULL, "pointer type required.");
2647       int idx = C->get_alias_index(at->is_ptr());
2648       if (idx == alias_idx)
2649         break; // Found
2650       if (!is_instance && (at->isa_oopptr() == NULL ||
2651                            !at->is_oopptr()->is_known_instance())) {
2652         break; // Do not skip store to general memory slice.
2653       }
2654       result = result->in(MemNode::Memory);
2655     }
2656     if (!is_instance)
2657       continue;  // don't search further for non-instance types
2658     // skip over a call which does not affect this memory slice
2659     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
2660       Node *proj_in = result->in(0);
2661       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
2662         break;  // hit one of our sentinels
2663       } else if (proj_in->is_Call()) {
2664         // ArrayCopy node processed here as well
2665         CallNode *call = proj_in->as_Call();
2666         if (!call->may_modify(toop, igvn)) {
2667           result = call->in(TypeFunc::Memory);
2668         }
2669       } else if (proj_in->is_Initialize()) {
2670         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
2671         // Stop if this is the initialization for the object instance which
2672         // which contains this memory slice, otherwise skip over it.
2673         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
2674           result = proj_in->in(TypeFunc::Memory);
2675         }
2676       } else if (proj_in->is_MemBar()) {
2677         if (proj_in->in(TypeFunc::Memory)->is_MergeMem() &&
2678             proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->is_Proj() &&
2679             proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->is_ArrayCopy()) {
2680           // clone
2681           ArrayCopyNode* ac = proj_in->in(TypeFunc::Memory)->as_MergeMem()->in(Compile::AliasIdxRaw)->in(0)->as_ArrayCopy();
2682           if (ac->may_modify(toop, igvn)) {
2683             break;
2684           }
2685         }
2686         result = proj_in->in(TypeFunc::Memory);
2687       }
2688     } else if (result->is_MergeMem()) {
2689       MergeMemNode *mmem = result->as_MergeMem();
2690       result = step_through_mergemem(mmem, alias_idx, toop);
2691       if (result == mmem->base_memory()) {
2692         // Didn't find instance memory, search through general slice recursively.
2693         result = mmem->memory_at(C->get_general_index(alias_idx));
2694         result = find_inst_mem(result, alias_idx, orig_phis);
2695         if (C->failing()) {
2696           return NULL;
2697         }
2698         mmem->set_memory_at(alias_idx, result);
2699       }
2700     } else if (result->is_Phi() &&
2701                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
2702       Node *un = result->as_Phi()->unique_input(igvn);
2703       if (un != NULL) {
2704         orig_phis.append_if_missing(result->as_Phi());
2705         result = un;
2706       } else {
2707         break;
2708       }
2709     } else if (result->is_ClearArray()) {
2710       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
2711         // Can not bypass initialization of the instance
2712         // we are looking for.
2713         break;
2714       }
2715       // Otherwise skip it (the call updated 'result' value).
2716     } else if (result->Opcode() == Op_SCMemProj) {
2717       Node* mem = result->in(0);
2718       Node* adr = NULL;
2719       if (mem->is_LoadStore()) {
2720         adr = mem->in(MemNode::Address);
2721       } else {
2722         assert(mem->Opcode() == Op_EncodeISOArray, "sanity");
2723         adr = mem->in(3); // Memory edge corresponds to destination array
2724       }
2725       const Type *at = igvn->type(adr);
2726       if (at != Type::TOP) {
2727         assert (at->isa_ptr() != NULL, "pointer type required.");
2728         int idx = C->get_alias_index(at->is_ptr());
2729         assert(idx != alias_idx, "Object is not scalar replaceable if a LoadStore node access its field");
2730         break;
2731       }
2732       result = mem->in(MemNode::Memory);
2733     }
2734   }
2735   if (result->is_Phi()) {
2736     PhiNode *mphi = result->as_Phi();
2737     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
2738     const TypePtr *t = mphi->adr_type();
2739     if (!is_instance) {
2740       // Push all non-instance Phis on the orig_phis worklist to update inputs
2741       // during Phase 4 if needed.
2742       orig_phis.append_if_missing(mphi);
2743     } else if (C->get_alias_index(t) != alias_idx) {
2744       // Create a new Phi with the specified alias index type.
2745       result = split_memory_phi(mphi, alias_idx, orig_phis);
2746     }
2747   }
2748   // the result is either MemNode, PhiNode, InitializeNode.
2749   return result;
2750 }
2751 
2752 //
2753 //  Convert the types of unescaped object to instance types where possible,
2754 //  propagate the new type information through the graph, and update memory
2755 //  edges and MergeMem inputs to reflect the new type.
2756 //
2757 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
2758 //  The processing is done in 4 phases:
2759 //
2760 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
2761 //            types for the CheckCastPP for allocations where possible.
2762 //            Propagate the new types through users as follows:
2763 //               casts and Phi:  push users on alloc_worklist
2764 //               AddP:  cast Base and Address inputs to the instance type
2765 //                      push any AddP users on alloc_worklist and push any memnode
2766 //                      users onto memnode_worklist.
2767 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
2768 //            search the Memory chain for a store with the appropriate type
2769 //            address type.  If a Phi is found, create a new version with
2770 //            the appropriate memory slices from each of the Phi inputs.
2771 //            For stores, process the users as follows:
2772 //               MemNode:  push on memnode_worklist
2773 //               MergeMem: push on mergemem_worklist
2774 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
2775 //            moving the first node encountered of each  instance type to the
2776 //            the input corresponding to its alias index.
2777 //            appropriate memory slice.
2778 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
2779 //
2780 // In the following example, the CheckCastPP nodes are the cast of allocation
2781 // results and the allocation of node 29 is unescaped and eligible to be an
2782 // instance type.
2783 //
2784 // We start with:
2785 //
2786 //     7 Parm #memory
2787 //    10  ConI  "12"
2788 //    19  CheckCastPP   "Foo"
2789 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2790 //    29  CheckCastPP   "Foo"
2791 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
2792 //
2793 //    40  StoreP  25   7  20   ... alias_index=4
2794 //    50  StoreP  35  40  30   ... alias_index=4
2795 //    60  StoreP  45  50  20   ... alias_index=4
2796 //    70  LoadP    _  60  30   ... alias_index=4
2797 //    80  Phi     75  50  60   Memory alias_index=4
2798 //    90  LoadP    _  80  30   ... alias_index=4
2799 //   100  LoadP    _  80  20   ... alias_index=4
2800 //
2801 //
2802 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
2803 // and creating a new alias index for node 30.  This gives:
2804 //
2805 //     7 Parm #memory
2806 //    10  ConI  "12"
2807 //    19  CheckCastPP   "Foo"
2808 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2809 //    29  CheckCastPP   "Foo"  iid=24
2810 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2811 //
2812 //    40  StoreP  25   7  20   ... alias_index=4
2813 //    50  StoreP  35  40  30   ... alias_index=6
2814 //    60  StoreP  45  50  20   ... alias_index=4
2815 //    70  LoadP    _  60  30   ... alias_index=6
2816 //    80  Phi     75  50  60   Memory alias_index=4
2817 //    90  LoadP    _  80  30   ... alias_index=6
2818 //   100  LoadP    _  80  20   ... alias_index=4
2819 //
2820 // In phase 2, new memory inputs are computed for the loads and stores,
2821 // And a new version of the phi is created.  In phase 4, the inputs to
2822 // node 80 are updated and then the memory nodes are updated with the
2823 // values computed in phase 2.  This results in:
2824 //
2825 //     7 Parm #memory
2826 //    10  ConI  "12"
2827 //    19  CheckCastPP   "Foo"
2828 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2829 //    29  CheckCastPP   "Foo"  iid=24
2830 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2831 //
2832 //    40  StoreP  25  7   20   ... alias_index=4
2833 //    50  StoreP  35  7   30   ... alias_index=6
2834 //    60  StoreP  45  40  20   ... alias_index=4
2835 //    70  LoadP    _  50  30   ... alias_index=6
2836 //    80  Phi     75  40  60   Memory alias_index=4
2837 //   120  Phi     75  50  50   Memory alias_index=6
2838 //    90  LoadP    _ 120  30   ... alias_index=6
2839 //   100  LoadP    _  80  20   ... alias_index=4
2840 //
2841 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist, GrowableArray<ArrayCopyNode*> &arraycopy_worklist) {
2842   GrowableArray<Node *>  memnode_worklist;
2843   GrowableArray<PhiNode *>  orig_phis;
2844   PhaseIterGVN  *igvn = _igvn;
2845   uint new_index_start = (uint) _compile->num_alias_types();
2846   Arena* arena = Thread::current()->resource_area();
2847   VectorSet visited(arena);
2848   ideal_nodes.clear(); // Reset for use with set_map/get_map.
2849   uint unique_old = _compile->unique();
2850 
2851   //  Phase 1:  Process possible allocations from alloc_worklist.
2852   //  Create instance types for the CheckCastPP for allocations where possible.
2853   //
2854   // (Note: don't forget to change the order of the second AddP node on
2855   //  the alloc_worklist if the order of the worklist processing is changed,
2856   //  see the comment in find_second_addp().)
2857   //
2858   while (alloc_worklist.length() != 0) {
2859     Node *n = alloc_worklist.pop();
2860     uint ni = n->_idx;
2861     if (n->is_Call()) {
2862       CallNode *alloc = n->as_Call();
2863       // copy escape information to call node
2864       PointsToNode* ptn = ptnode_adr(alloc->_idx);
2865       PointsToNode::EscapeState es = ptn->escape_state();
2866       // We have an allocation or call which returns a Java object,
2867       // see if it is unescaped.
2868       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
2869         continue;
2870       // Find CheckCastPP for the allocate or for the return value of a call
2871       n = alloc->result_cast();
2872       if (n == NULL) {            // No uses except Initialize node
2873         if (alloc->is_Allocate()) {
2874           // Set the scalar_replaceable flag for allocation
2875           // so it could be eliminated if it has no uses.
2876           alloc->as_Allocate()->_is_scalar_replaceable = true;
2877         }
2878         if (alloc->is_CallStaticJava()) {
2879           // Set the scalar_replaceable flag for boxing method
2880           // so it could be eliminated if it has no uses.
2881           alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2882         }
2883         continue;
2884       }
2885       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
2886         assert(!alloc->is_Allocate(), "allocation should have unique type");
2887         continue;
2888       }
2889 
2890       // The inline code for Object.clone() casts the allocation result to
2891       // java.lang.Object and then to the actual type of the allocated
2892       // object. Detect this case and use the second cast.
2893       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
2894       // the allocation result is cast to java.lang.Object and then
2895       // to the actual Array type.
2896       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
2897           && (alloc->is_AllocateArray() ||
2898               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
2899         Node *cast2 = NULL;
2900         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2901           Node *use = n->fast_out(i);
2902           if (use->is_CheckCastPP()) {
2903             cast2 = use;
2904             break;
2905           }
2906         }
2907         if (cast2 != NULL) {
2908           n = cast2;
2909         } else {
2910           // Non-scalar replaceable if the allocation type is unknown statically
2911           // (reflection allocation), the object can't be restored during
2912           // deoptimization without precise type.
2913           continue;
2914         }
2915       }
2916 
2917       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
2918       if (t == NULL)
2919         continue;  // not a TypeOopPtr
2920       if (!t->klass_is_exact())
2921         continue; // not an unique type
2922 
2923       if (alloc->is_Allocate()) {
2924         // Set the scalar_replaceable flag for allocation
2925         // so it could be eliminated.
2926         alloc->as_Allocate()->_is_scalar_replaceable = true;
2927       }
2928       if (alloc->is_CallStaticJava()) {
2929         // Set the scalar_replaceable flag for boxing method
2930         // so it could be eliminated.
2931         alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2932       }
2933       set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
2934       // in order for an object to be scalar-replaceable, it must be:
2935       //   - a direct allocation (not a call returning an object)
2936       //   - non-escaping
2937       //   - eligible to be a unique type
2938       //   - not determined to be ineligible by escape analysis
2939       set_map(alloc, n);
2940       set_map(n, alloc);
2941       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
2942       igvn->hash_delete(n);
2943       igvn->set_type(n,  tinst);
2944       n->raise_bottom_type(tinst);
2945       igvn->hash_insert(n);
2946       record_for_optimizer(n);
2947       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
2948 
2949         // First, put on the worklist all Field edges from Connection Graph
2950         // which is more accurate than putting immediate users from Ideal Graph.
2951         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
2952           PointsToNode* tgt = e.get();
2953           if (tgt->is_Arraycopy()) {
2954             continue;
2955           }
2956           Node* use = tgt->ideal_node();
2957           assert(tgt->is_Field() && use->is_AddP(),
2958                  "only AddP nodes are Field edges in CG");
2959           if (use->outcnt() > 0) { // Don't process dead nodes
2960             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
2961             if (addp2 != NULL) {
2962               assert(alloc->is_AllocateArray(),"array allocation was expected");
2963               alloc_worklist.append_if_missing(addp2);
2964             }
2965             alloc_worklist.append_if_missing(use);
2966           }
2967         }
2968 
2969         // An allocation may have an Initialize which has raw stores. Scan
2970         // the users of the raw allocation result and push AddP users
2971         // on alloc_worklist.
2972         Node *raw_result = alloc->proj_out(TypeFunc::Parms);
2973         assert (raw_result != NULL, "must have an allocation result");
2974         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
2975           Node *use = raw_result->fast_out(i);
2976           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
2977             Node* addp2 = find_second_addp(use, raw_result);
2978             if (addp2 != NULL) {
2979               assert(alloc->is_AllocateArray(),"array allocation was expected");
2980               alloc_worklist.append_if_missing(addp2);
2981             }
2982             alloc_worklist.append_if_missing(use);
2983           } else if (use->is_MemBar()) {
2984             memnode_worklist.append_if_missing(use);
2985           }
2986         }
2987       }
2988     } else if (n->is_AddP()) {
2989       JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
2990       if (jobj == NULL || jobj == phantom_obj) {
2991 #ifdef ASSERT
2992         ptnode_adr(get_addp_base(n)->_idx)->dump();
2993         ptnode_adr(n->_idx)->dump();
2994         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
2995 #endif
2996         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
2997         return;
2998       }
2999       Node *base = get_map(jobj->idx());  // CheckCastPP node
3000       if (!split_AddP(n, base)) continue; // wrong type from dead path
3001     } else if (n->is_Phi() ||
3002                n->is_CheckCastPP() ||
3003                n->is_EncodeP() ||
3004                n->is_DecodeN() ||
3005                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
3006       if (visited.test_set(n->_idx)) {
3007         assert(n->is_Phi(), "loops only through Phi's");
3008         continue;  // already processed
3009       }
3010       JavaObjectNode* jobj = unique_java_object(n);
3011       if (jobj == NULL || jobj == phantom_obj) {
3012 #ifdef ASSERT
3013         ptnode_adr(n->_idx)->dump();
3014         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3015 #endif
3016         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3017         return;
3018       } else {
3019         Node *val = get_map(jobj->idx());   // CheckCastPP node
3020         TypeNode *tn = n->as_Type();
3021         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
3022         assert(tinst != NULL && tinst->is_known_instance() &&
3023                tinst->instance_id() == jobj->idx() , "instance type expected.");
3024 
3025         const Type *tn_type = igvn->type(tn);
3026         const TypeOopPtr *tn_t;
3027         if (tn_type->isa_narrowoop()) {
3028           tn_t = tn_type->make_ptr()->isa_oopptr();
3029         } else {
3030           tn_t = tn_type->isa_oopptr();
3031         }
3032         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
3033           if (tn_type->isa_narrowoop()) {
3034             tn_type = tinst->make_narrowoop();
3035           } else {
3036             tn_type = tinst;
3037           }
3038           igvn->hash_delete(tn);
3039           igvn->set_type(tn, tn_type);
3040           tn->set_type(tn_type);
3041           igvn->hash_insert(tn);
3042           record_for_optimizer(n);
3043         } else {
3044           assert(tn_type == TypePtr::NULL_PTR ||
3045                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
3046                  "unexpected type");
3047           continue; // Skip dead path with different type
3048         }
3049       }
3050     } else {
3051       debug_only(n->dump();)
3052       assert(false, "EA: unexpected node");
3053       continue;
3054     }
3055     // push allocation's users on appropriate worklist
3056     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3057       Node *use = n->fast_out(i);
3058       if(use->is_Mem() && use->in(MemNode::Address) == n) {
3059         // Load/store to instance's field
3060         memnode_worklist.append_if_missing(use);
3061       } else if (use->is_MemBar()) {
3062         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3063           memnode_worklist.append_if_missing(use);
3064         }
3065       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
3066         Node* addp2 = find_second_addp(use, n);
3067         if (addp2 != NULL) {
3068           alloc_worklist.append_if_missing(addp2);
3069         }
3070         alloc_worklist.append_if_missing(use);
3071       } else if (use->is_Phi() ||
3072                  use->is_CheckCastPP() ||
3073                  use->is_EncodeNarrowPtr() ||
3074                  use->is_DecodeNarrowPtr() ||
3075                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
3076         alloc_worklist.append_if_missing(use);
3077 #ifdef ASSERT
3078       } else if (use->is_Mem()) {
3079         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
3080       } else if (use->is_MergeMem()) {
3081         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3082       } else if (use->is_SafePoint()) {
3083         // Look for MergeMem nodes for calls which reference unique allocation
3084         // (through CheckCastPP nodes) even for debug info.
3085         Node* m = use->in(TypeFunc::Memory);
3086         if (m->is_MergeMem()) {
3087           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3088         }
3089       } else if (use->Opcode() == Op_EncodeISOArray) {
3090         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3091           // EncodeISOArray overwrites destination array
3092           memnode_worklist.append_if_missing(use);
3093         }
3094       } else {
3095         uint op = use->Opcode();
3096         if (!(op == Op_CmpP || op == Op_Conv2B ||
3097               op == Op_CastP2X || op == Op_StoreCM ||
3098               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp ||
3099               op == Op_StrEquals || op == Op_StrIndexOf)) {
3100           n->dump();
3101           use->dump();
3102           assert(false, "EA: missing allocation reference path");
3103         }
3104 #endif
3105       }
3106     }
3107 
3108   }
3109 
3110   // Go over all ArrayCopy nodes and if one of the inputs has a unique
3111   // type, record it in the ArrayCopy node so we know what memory this
3112   // node uses/modified.
3113   for (int next = 0; next < arraycopy_worklist.length(); next++) {
3114     ArrayCopyNode* ac = arraycopy_worklist.at(next);
3115     Node* dest = ac->in(ArrayCopyNode::Dest);
3116     if (dest->is_AddP()) {
3117       dest = get_addp_base(dest);
3118     }
3119     JavaObjectNode* jobj = unique_java_object(dest);
3120     if (jobj != NULL) {
3121       Node *base = get_map(jobj->idx());
3122       if (base != NULL) {
3123         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3124         ac->_dest_type = base_t;
3125       }
3126     }
3127     Node* src = ac->in(ArrayCopyNode::Src);
3128     if (src->is_AddP()) {
3129       src = get_addp_base(src);
3130     }
3131     jobj = unique_java_object(src);
3132     if (jobj != NULL) {
3133       Node* base = get_map(jobj->idx());
3134       if (base != NULL) {
3135         const TypeOopPtr *base_t = _igvn->type(base)->isa_oopptr();
3136         ac->_src_type = base_t;
3137       }
3138     }
3139   }
3140 
3141   // New alias types were created in split_AddP().
3142   uint new_index_end = (uint) _compile->num_alias_types();
3143   assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
3144 
3145   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
3146   //            compute new values for Memory inputs  (the Memory inputs are not
3147   //            actually updated until phase 4.)
3148   if (memnode_worklist.length() == 0)
3149     return;  // nothing to do
3150   while (memnode_worklist.length() != 0) {
3151     Node *n = memnode_worklist.pop();
3152     if (visited.test_set(n->_idx))
3153       continue;
3154     if (n->is_Phi() || n->is_ClearArray()) {
3155       // we don't need to do anything, but the users must be pushed
3156     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
3157       // we don't need to do anything, but the users must be pushed
3158       n = n->as_MemBar()->proj_out(TypeFunc::Memory);
3159       if (n == NULL)
3160         continue;
3161     } else if (n->Opcode() == Op_EncodeISOArray) {
3162       // get the memory projection
3163       n = n->find_out_with(Op_SCMemProj);
3164       assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3165     } else {
3166       assert(n->is_Mem(), "memory node required.");
3167       Node *addr = n->in(MemNode::Address);
3168       const Type *addr_t = igvn->type(addr);
3169       if (addr_t == Type::TOP)
3170         continue;
3171       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
3172       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
3173       assert ((uint)alias_idx < new_index_end, "wrong alias index");
3174       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
3175       if (_compile->failing()) {
3176         return;
3177       }
3178       if (mem != n->in(MemNode::Memory)) {
3179         // We delay the memory edge update since we need old one in
3180         // MergeMem code below when instances memory slices are separated.
3181         set_map(n, mem);
3182       }
3183       if (n->is_Load()) {
3184         continue;  // don't push users
3185       } else if (n->is_LoadStore()) {
3186         // get the memory projection
3187         n = n->find_out_with(Op_SCMemProj);
3188         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3189       }
3190     }
3191     // push user on appropriate worklist
3192     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3193       Node *use = n->fast_out(i);
3194       if (use->is_Phi() || use->is_ClearArray()) {
3195         memnode_worklist.append_if_missing(use);
3196       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
3197         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
3198           continue;
3199         memnode_worklist.append_if_missing(use);
3200       } else if (use->is_MemBar()) {
3201         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3202           memnode_worklist.append_if_missing(use);
3203         }
3204 #ifdef ASSERT
3205       } else if(use->is_Mem()) {
3206         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
3207       } else if (use->is_MergeMem()) {
3208         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3209       } else if (use->Opcode() == Op_EncodeISOArray) {
3210         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3211           // EncodeISOArray overwrites destination array
3212           memnode_worklist.append_if_missing(use);
3213         }
3214       } else {
3215         uint op = use->Opcode();
3216         if (!(op == Op_StoreCM ||
3217               (op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&
3218                strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||
3219               op == Op_AryEq || op == Op_StrComp ||
3220               op == Op_StrEquals || op == Op_StrIndexOf)) {
3221           n->dump();
3222           use->dump();
3223           assert(false, "EA: missing memory path");
3224         }
3225 #endif
3226       }
3227     }
3228   }
3229 
3230   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
3231   //            Walk each memory slice moving the first node encountered of each
3232   //            instance type to the the input corresponding to its alias index.
3233   uint length = _mergemem_worklist.length();
3234   for( uint next = 0; next < length; ++next ) {
3235     MergeMemNode* nmm = _mergemem_worklist.at(next);
3236     assert(!visited.test_set(nmm->_idx), "should not be visited before");
3237     // Note: we don't want to use MergeMemStream here because we only want to
3238     // scan inputs which exist at the start, not ones we add during processing.
3239     // Note 2: MergeMem may already contains instance memory slices added
3240     // during find_inst_mem() call when memory nodes were processed above.
3241     igvn->hash_delete(nmm);
3242     uint nslices = nmm->req();
3243     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
3244       Node* mem = nmm->in(i);
3245       Node* cur = NULL;
3246       if (mem == NULL || mem->is_top())
3247         continue;
3248       // First, update mergemem by moving memory nodes to corresponding slices
3249       // if their type became more precise since this mergemem was created.
3250       while (mem->is_Mem()) {
3251         const Type *at = igvn->type(mem->in(MemNode::Address));
3252         if (at != Type::TOP) {
3253           assert (at->isa_ptr() != NULL, "pointer type required.");
3254           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
3255           if (idx == i) {
3256             if (cur == NULL)
3257               cur = mem;
3258           } else {
3259             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
3260               nmm->set_memory_at(idx, mem);
3261             }
3262           }
3263         }
3264         mem = mem->in(MemNode::Memory);
3265       }
3266       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
3267       // Find any instance of the current type if we haven't encountered
3268       // already a memory slice of the instance along the memory chain.
3269       for (uint ni = new_index_start; ni < new_index_end; ni++) {
3270         if((uint)_compile->get_general_index(ni) == i) {
3271           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
3272           if (nmm->is_empty_memory(m)) {
3273             Node* result = find_inst_mem(mem, ni, orig_phis);
3274             if (_compile->failing()) {
3275               return;
3276             }
3277             nmm->set_memory_at(ni, result);
3278           }
3279         }
3280       }
3281     }
3282     // Find the rest of instances values
3283     for (uint ni = new_index_start; ni < new_index_end; ni++) {
3284       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
3285       Node* result = step_through_mergemem(nmm, ni, tinst);
3286       if (result == nmm->base_memory()) {
3287         // Didn't find instance memory, search through general slice recursively.
3288         result = nmm->memory_at(_compile->get_general_index(ni));
3289         result = find_inst_mem(result, ni, orig_phis);
3290         if (_compile->failing()) {
3291           return;
3292         }
3293         nmm->set_memory_at(ni, result);
3294       }
3295     }
3296     igvn->hash_insert(nmm);
3297     record_for_optimizer(nmm);
3298   }
3299 
3300   //  Phase 4:  Update the inputs of non-instance memory Phis and
3301   //            the Memory input of memnodes
3302   // First update the inputs of any non-instance Phi's from
3303   // which we split out an instance Phi.  Note we don't have
3304   // to recursively process Phi's encounted on the input memory
3305   // chains as is done in split_memory_phi() since they  will
3306   // also be processed here.
3307   for (int j = 0; j < orig_phis.length(); j++) {
3308     PhiNode *phi = orig_phis.at(j);
3309     int alias_idx = _compile->get_alias_index(phi->adr_type());
3310     igvn->hash_delete(phi);
3311     for (uint i = 1; i < phi->req(); i++) {
3312       Node *mem = phi->in(i);
3313       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
3314       if (_compile->failing()) {
3315         return;
3316       }
3317       if (mem != new_mem) {
3318         phi->set_req(i, new_mem);
3319       }
3320     }
3321     igvn->hash_insert(phi);
3322     record_for_optimizer(phi);
3323   }
3324 
3325   // Update the memory inputs of MemNodes with the value we computed
3326   // in Phase 2 and move stores memory users to corresponding memory slices.
3327   // Disable memory split verification code until the fix for 6984348.
3328   // Currently it produces false negative results since it does not cover all cases.
3329 #if 0 // ifdef ASSERT
3330   visited.Reset();
3331   Node_Stack old_mems(arena, _compile->unique() >> 2);
3332 #endif
3333   for (uint i = 0; i < ideal_nodes.size(); i++) {
3334     Node*    n = ideal_nodes.at(i);
3335     Node* nmem = get_map(n->_idx);
3336     assert(nmem != NULL, "sanity");
3337     if (n->is_Mem()) {
3338 #if 0 // ifdef ASSERT
3339       Node* old_mem = n->in(MemNode::Memory);
3340       if (!visited.test_set(old_mem->_idx)) {
3341         old_mems.push(old_mem, old_mem->outcnt());
3342       }
3343 #endif
3344       assert(n->in(MemNode::Memory) != nmem, "sanity");
3345       if (!n->is_Load()) {
3346         // Move memory users of a store first.
3347         move_inst_mem(n, orig_phis);
3348       }
3349       // Now update memory input
3350       igvn->hash_delete(n);
3351       n->set_req(MemNode::Memory, nmem);
3352       igvn->hash_insert(n);
3353       record_for_optimizer(n);
3354     } else {
3355       assert(n->is_Allocate() || n->is_CheckCastPP() ||
3356              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
3357     }
3358   }
3359 #if 0 // ifdef ASSERT
3360   // Verify that memory was split correctly
3361   while (old_mems.is_nonempty()) {
3362     Node* old_mem = old_mems.node();
3363     uint  old_cnt = old_mems.index();
3364     old_mems.pop();
3365     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
3366   }
3367 #endif
3368 }
3369 
3370 #ifndef PRODUCT
3371 static const char *node_type_names[] = {
3372   "UnknownType",
3373   "JavaObject",
3374   "LocalVar",
3375   "Field",
3376   "Arraycopy"
3377 };
3378 
3379 static const char *esc_names[] = {
3380   "UnknownEscape",
3381   "NoEscape",
3382   "ArgEscape",
3383   "GlobalEscape"
3384 };
3385 
3386 void PointsToNode::dump(bool print_state) const {
3387   NodeType nt = node_type();
3388   tty->print("%s ", node_type_names[(int) nt]);
3389   if (print_state) {
3390     EscapeState es = escape_state();
3391     EscapeState fields_es = fields_escape_state();
3392     tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
3393     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
3394       tty->print("NSR ");
3395   }
3396   if (is_Field()) {
3397     FieldNode* f = (FieldNode*)this;
3398     if (f->is_oop())
3399       tty->print("oop ");
3400     if (f->offset() > 0)
3401       tty->print("+%d ", f->offset());
3402     tty->print("(");
3403     for (BaseIterator i(f); i.has_next(); i.next()) {
3404       PointsToNode* b = i.get();
3405       tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
3406     }
3407     tty->print(" )");
3408   }
3409   tty->print("[");
3410   for (EdgeIterator i(this); i.has_next(); i.next()) {
3411     PointsToNode* e = i.get();
3412     tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
3413   }
3414   tty->print(" [");
3415   for (UseIterator i(this); i.has_next(); i.next()) {
3416     PointsToNode* u = i.get();
3417     bool is_base = false;
3418     if (PointsToNode::is_base_use(u)) {
3419       is_base = true;
3420       u = PointsToNode::get_use_node(u)->as_Field();
3421     }
3422     tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
3423   }
3424   tty->print(" ]]  ");
3425   if (_node == NULL)
3426     tty->print_cr("<null>");
3427   else
3428     _node->dump();
3429 }
3430 
3431 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
3432   bool first = true;
3433   int ptnodes_length = ptnodes_worklist.length();
3434   for (int i = 0; i < ptnodes_length; i++) {
3435     PointsToNode *ptn = ptnodes_worklist.at(i);
3436     if (ptn == NULL || !ptn->is_JavaObject())
3437       continue;
3438     PointsToNode::EscapeState es = ptn->escape_state();
3439     if ((es != PointsToNode::NoEscape) && !Verbose) {
3440       continue;
3441     }
3442     Node* n = ptn->ideal_node();
3443     if (n->is_Allocate() || (n->is_CallStaticJava() &&
3444                              n->as_CallStaticJava()->is_boxing_method())) {
3445       if (first) {
3446         tty->cr();
3447         tty->print("======== Connection graph for ");
3448         _compile->method()->print_short_name();
3449         tty->cr();
3450         first = false;
3451       }
3452       ptn->dump();
3453       // Print all locals and fields which reference this allocation
3454       for (UseIterator j(ptn); j.has_next(); j.next()) {
3455         PointsToNode* use = j.get();
3456         if (use->is_LocalVar()) {
3457           use->dump(Verbose);
3458         } else if (Verbose) {
3459           use->dump();
3460         }
3461       }
3462       tty->cr();
3463     }
3464   }
3465 }
3466 #endif