1 /*
   2  * Copyright (c) 2005, 2019, 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/callnode.hpp"
  32 #include "opto/cfgnode.hpp"
  33 #include "opto/compile.hpp"
  34 #include "opto/escape.hpp"
  35 #include "opto/phaseX.hpp"
  36 #include "opto/rootnode.hpp"
  37 #if INCLUDE_ALL_GCS
  38 #include "gc_implementation/shenandoah/c2/shenandoahSupport.hpp"
  39 #endif
  40 
  41 ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :
  42   _nodes(C->comp_arena(), C->unique(), C->unique(), NULL),
  43   _in_worklist(C->comp_arena()),
  44   _next_pidx(0),
  45   _collecting(true),
  46   _verify(false),
  47   _compile(C),
  48   _igvn(igvn),
  49   _node_map(C->comp_arena()) {
  50   // Add unknown java object.
  51   add_java_object(C->top(), PointsToNode::GlobalEscape);
  52   phantom_obj = ptnode_adr(C->top()->_idx)->as_JavaObject();
  53   // Add ConP(#NULL) and ConN(#NULL) nodes.
  54   Node* oop_null = igvn->zerocon(T_OBJECT);
  55   assert(oop_null->_idx < nodes_size(), "should be created already");
  56   add_java_object(oop_null, PointsToNode::NoEscape);
  57   null_obj = ptnode_adr(oop_null->_idx)->as_JavaObject();
  58   if (UseCompressedOops) {
  59     Node* noop_null = igvn->zerocon(T_NARROWOOP);
  60     assert(noop_null->_idx < nodes_size(), "should be created already");
  61     map_ideal_node(noop_null, null_obj);
  62   }
  63   _pcmp_neq = NULL; // Should be initialized
  64   _pcmp_eq  = NULL;
  65 }
  66 
  67 bool ConnectionGraph::has_candidates(Compile *C) {
  68   // EA brings benefits only when the code has allocations and/or locks which
  69   // are represented by ideal Macro nodes.
  70   int cnt = C->macro_count();
  71   for (int i = 0; i < cnt; i++) {
  72     Node *n = C->macro_node(i);
  73     if (n->is_Allocate())
  74       return true;
  75     if (n->is_Lock()) {
  76       Node* obj = n->as_Lock()->obj_node()->uncast();
  77       if (!(obj->is_Parm() || obj->is_Con()))
  78         return true;
  79     }
  80     if (n->is_CallStaticJava() &&
  81         n->as_CallStaticJava()->is_boxing_method()) {
  82       return true;
  83     }
  84   }
  85   return false;
  86 }
  87 
  88 void ConnectionGraph::do_analysis(Compile *C, PhaseIterGVN *igvn) {
  89   Compile::TracePhase t2("escapeAnalysis", &Phase::_t_escapeAnalysis, true);
  90   ResourceMark rm;
  91 
  92   // Add ConP#NULL and ConN#NULL nodes before ConnectionGraph construction
  93   // to create space for them in ConnectionGraph::_nodes[].
  94   Node* oop_null = igvn->zerocon(T_OBJECT);
  95   Node* noop_null = igvn->zerocon(T_NARROWOOP);
  96   ConnectionGraph* congraph = new(C->comp_arena()) ConnectionGraph(C, igvn);
  97   // Perform escape analysis
  98   if (congraph->compute_escape()) {
  99     // There are non escaping objects.
 100     C->set_congraph(congraph);
 101   }
 102   // Cleanup.
 103   if (oop_null->outcnt() == 0)
 104     igvn->hash_delete(oop_null);
 105   if (noop_null->outcnt() == 0)
 106     igvn->hash_delete(noop_null);
 107 }
 108 
 109 bool ConnectionGraph::compute_escape() {
 110   Compile* C = _compile;
 111   PhaseGVN* igvn = _igvn;
 112 
 113   // Worklists used by EA.
 114   Unique_Node_List delayed_worklist;
 115   GrowableArray<Node*> alloc_worklist;
 116   GrowableArray<Node*> ptr_cmp_worklist;
 117   GrowableArray<Node*> storestore_worklist;
 118   GrowableArray<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 t3("connectionGraph", &Phase::_t_connectionGraph, true);
 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     }
 179     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
 180       Node* m = n->fast_out(i);   // Get user
 181       ideal_nodes.push(m);
 182     }
 183   }
 184   if (non_escaped_worklist.length() == 0) {
 185     _collecting = false;
 186     return false; // Nothing to do.
 187   }
 188   // Add final simple edges to graph.
 189   while(delayed_worklist.size() > 0) {
 190     Node* n = delayed_worklist.pop();
 191     add_final_edges(n);
 192   }
 193   int ptnodes_length = ptnodes_worklist.length();
 194 
 195 #ifdef ASSERT
 196   if (VerifyConnectionGraph) {
 197     // Verify that no new simple edges could be created and all
 198     // local vars has edges.
 199     _verify = true;
 200     for (int next = 0; next < ptnodes_length; ++next) {
 201       PointsToNode* ptn = ptnodes_worklist.at(next);
 202       add_final_edges(ptn->ideal_node());
 203       if (ptn->is_LocalVar() && ptn->edge_count() == 0) {
 204         ptn->dump();
 205         assert(ptn->as_LocalVar()->edge_count() > 0, "sanity");
 206       }
 207     }
 208     _verify = false;
 209   }
 210 #endif
 211   // Bytecode analyzer BCEscapeAnalyzer, used for Call nodes
 212   // processing, calls to CI to resolve symbols (types, fields, methods)
 213   // referenced in bytecode. During symbol resolution VM may throw
 214   // an exception which CI cleans and converts to compilation failure.
 215   if (C->failing())  return false;
 216 
 217   // 2. Finish Graph construction by propagating references to all
 218   //    java objects through graph.
 219   if (!complete_connection_graph(ptnodes_worklist, non_escaped_worklist,
 220                                  java_objects_worklist, oop_fields_worklist)) {
 221     // All objects escaped or hit time or iterations limits.
 222     _collecting = false;
 223     return false;
 224   }
 225 
 226   // 3. Adjust scalar_replaceable state of nonescaping objects and push
 227   //    scalar replaceable allocations on alloc_worklist for processing
 228   //    in split_unique_types().
 229   int non_escaped_length = non_escaped_worklist.length();
 230   for (int next = 0; next < non_escaped_length; next++) {
 231     JavaObjectNode* ptn = non_escaped_worklist.at(next);
 232     bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
 233     Node* n = ptn->ideal_node();
 234     if (n->is_Allocate()) {
 235       n->as_Allocate()->_is_non_escaping = noescape;
 236     }
 237     if (n->is_CallStaticJava()) {
 238       n->as_CallStaticJava()->_is_non_escaping = noescape;
 239     }
 240     if (noescape && ptn->scalar_replaceable()) {
 241       adjust_scalar_replaceable_state(ptn);
 242       if (ptn->scalar_replaceable()) {
 243         alloc_worklist.append(ptn->ideal_node());
 244       }
 245     }
 246   }
 247 
 248 #ifdef ASSERT
 249   if (VerifyConnectionGraph) {
 250     // Verify that graph is complete - no new edges could be added or needed.
 251     verify_connection_graph(ptnodes_worklist, non_escaped_worklist,
 252                             java_objects_worklist, addp_worklist);
 253   }
 254   assert(C->unique() == nodes_size(), "no new ideal nodes should be added during ConnectionGraph build");
 255   assert(null_obj->escape_state() == PointsToNode::NoEscape &&
 256          null_obj->edge_count() == 0 &&
 257          !null_obj->arraycopy_src() &&
 258          !null_obj->arraycopy_dst(), "sanity");
 259 #endif
 260 
 261   _collecting = false;
 262 
 263   } // TracePhase t3("connectionGraph")
 264 
 265   // 4. Optimize ideal graph based on EA information.
 266   bool has_non_escaping_obj = (non_escaped_worklist.length() > 0);
 267   if (has_non_escaping_obj) {
 268     optimize_ideal_graph(ptr_cmp_worklist, storestore_worklist);
 269   }
 270 
 271 #ifndef PRODUCT
 272   if (PrintEscapeAnalysis) {
 273     dump(ptnodes_worklist); // Dump ConnectionGraph
 274   }
 275 #endif
 276 
 277   bool has_scalar_replaceable_candidates = (alloc_worklist.length() > 0);
 278 #ifdef ASSERT
 279   if (VerifyConnectionGraph) {
 280     int alloc_length = alloc_worklist.length();
 281     for (int next = 0; next < alloc_length; ++next) {
 282       Node* n = alloc_worklist.at(next);
 283       PointsToNode* ptn = ptnode_adr(n->_idx);
 284       assert(ptn->escape_state() == PointsToNode::NoEscape && ptn->scalar_replaceable(), "sanity");
 285     }
 286   }
 287 #endif
 288 
 289   // 5. Separate memory graph for scalar replaceable allcations.
 290   if (has_scalar_replaceable_candidates &&
 291       C->AliasLevel() >= 3 && EliminateAllocations) {
 292     // Now use the escape information to create unique types for
 293     // scalar replaceable objects.
 294     split_unique_types(alloc_worklist);
 295     if (C->failing())  return false;
 296     C->print_method(PHASE_AFTER_EA, 2);
 297 
 298 #ifdef ASSERT
 299   } else if (Verbose && (PrintEscapeAnalysis || PrintEliminateAllocations)) {
 300     tty->print("=== No allocations eliminated for ");
 301     C->method()->print_short_name();
 302     if(!EliminateAllocations) {
 303       tty->print(" since EliminateAllocations is off ===");
 304     } else if(!has_scalar_replaceable_candidates) {
 305       tty->print(" since there are no scalar replaceable candidates ===");
 306     } else if(C->AliasLevel() < 3) {
 307       tty->print(" since AliasLevel < 3 ===");
 308     }
 309     tty->cr();
 310 #endif
 311   }
 312   return has_non_escaping_obj;
 313 }
 314 
 315 // Utility function for nodes that load an object
 316 void ConnectionGraph::add_objload_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 317   // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 318   // ThreadLocal has RawPtr type.
 319   const Type* t = _igvn->type(n);
 320   if (t->make_ptr() != NULL) {
 321     Node* adr = n->in(MemNode::Address);
 322 #ifdef ASSERT
 323     if (!adr->is_AddP()) {
 324       assert(_igvn->type(adr)->isa_rawptr(), "sanity");
 325     } else {
 326       assert((ptnode_adr(adr->_idx) == NULL ||
 327               ptnode_adr(adr->_idx)->as_Field()->is_oop()), "sanity");
 328     }
 329 #endif
 330     add_local_var_and_edge(n, PointsToNode::NoEscape,
 331                            adr, delayed_worklist);
 332   }
 333 }
 334 
 335 // Populate Connection Graph with PointsTo nodes and create simple
 336 // connection graph edges.
 337 void ConnectionGraph::add_node_to_connection_graph(Node *n, Unique_Node_List *delayed_worklist) {
 338   assert(!_verify, "this method sould not be called for verification");
 339   PhaseGVN* igvn = _igvn;
 340   uint n_idx = n->_idx;
 341   PointsToNode* n_ptn = ptnode_adr(n_idx);
 342   if (n_ptn != NULL)
 343     return; // No need to redefine PointsTo node during first iteration.
 344 
 345   if (n->is_Call()) {
 346     // Arguments to allocation and locking don't escape.
 347     if (n->is_AbstractLock()) {
 348       // Put Lock and Unlock nodes on IGVN worklist to process them during
 349       // first IGVN optimization when escape information is still available.
 350       record_for_optimizer(n);
 351     } else if (n->is_Allocate()) {
 352       add_call_node(n->as_Call());
 353       record_for_optimizer(n);
 354     } else {
 355       if (n->is_CallStaticJava()) {
 356         const char* name = n->as_CallStaticJava()->_name;
 357         if (name != NULL && strcmp(name, "uncommon_trap") == 0)
 358           return; // Skip uncommon traps
 359       }
 360       // Don't mark as processed since call's arguments have to be processed.
 361       delayed_worklist->push(n);
 362       // Check if a call returns an object.
 363       if ((n->as_Call()->returns_pointer() &&
 364            n->as_Call()->proj_out(TypeFunc::Parms) != NULL) ||
 365           (n->is_CallStaticJava() &&
 366            n->as_CallStaticJava()->is_boxing_method())) {
 367         add_call_node(n->as_Call());
 368       }
 369     }
 370     return;
 371   }
 372   // Put this check here to process call arguments since some call nodes
 373   // point to phantom_obj.
 374   if (n_ptn == phantom_obj || n_ptn == null_obj)
 375     return; // Skip predefined nodes.
 376 
 377   int opcode = n->Opcode();
 378   switch (opcode) {
 379     case Op_AddP: {
 380       Node* base = get_addp_base(n);
 381       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 382       // Field nodes are created for all field types. They are used in
 383       // adjust_scalar_replaceable_state() and split_unique_types().
 384       // Note, non-oop fields will have only base edges in Connection
 385       // Graph because such fields are not used for oop loads and stores.
 386       int offset = address_offset(n, igvn);
 387       add_field(n, PointsToNode::NoEscape, offset);
 388       if (ptn_base == NULL) {
 389         delayed_worklist->push(n); // Process it later.
 390       } else {
 391         n_ptn = ptnode_adr(n_idx);
 392         add_base(n_ptn->as_Field(), ptn_base);
 393       }
 394       break;
 395     }
 396     case Op_CastX2P: {
 397       map_ideal_node(n, phantom_obj);
 398       break;
 399     }
 400     case Op_CastPP:
 401     case Op_CheckCastPP:
 402     case Op_EncodeP:
 403     case Op_DecodeN:
 404     case Op_EncodePKlass:
 405     case Op_DecodeNKlass: {
 406       add_local_var_and_edge(n, PointsToNode::NoEscape,
 407                              n->in(1), delayed_worklist);
 408       break;
 409     }
 410     case Op_CMoveP: {
 411       add_local_var(n, PointsToNode::NoEscape);
 412       // Do not add edges during first iteration because some could be
 413       // not defined yet.
 414       delayed_worklist->push(n);
 415       break;
 416     }
 417     case Op_ConP:
 418     case Op_ConN:
 419     case Op_ConNKlass: {
 420       // assume all oop constants globally escape except for null
 421       PointsToNode::EscapeState es;
 422       const Type* t = igvn->type(n);
 423       if (t == TypePtr::NULL_PTR || t == TypeNarrowOop::NULL_PTR) {
 424         es = PointsToNode::NoEscape;
 425       } else {
 426         es = PointsToNode::GlobalEscape;
 427       }
 428       add_java_object(n, es);
 429       break;
 430     }
 431     case Op_CreateEx: {
 432       // assume that all exception objects globally escape
 433       map_ideal_node(n, phantom_obj);
 434       break;
 435     }
 436     case Op_LoadKlass:
 437     case Op_LoadNKlass: {
 438       // Unknown class is loaded
 439       map_ideal_node(n, phantom_obj);
 440       break;
 441     }
 442     case Op_LoadP:
 443     case Op_LoadN:
 444     case Op_LoadPLocked: {
 445       add_objload_to_connection_graph(n, delayed_worklist);
 446       break;
 447     }
 448     case Op_Parm: {
 449       map_ideal_node(n, phantom_obj);
 450       break;
 451     }
 452     case Op_PartialSubtypeCheck: {
 453       // Produces Null or notNull and is used in only in CmpP so
 454       // phantom_obj could be used.
 455       map_ideal_node(n, phantom_obj); // Result is unknown
 456       break;
 457     }
 458     case Op_Phi: {
 459       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 460       // ThreadLocal has RawPtr type.
 461       const Type* t = n->as_Phi()->type();
 462       if (t->make_ptr() != NULL) {
 463         add_local_var(n, PointsToNode::NoEscape);
 464         // Do not add edges during first iteration because some could be
 465         // not defined yet.
 466         delayed_worklist->push(n);
 467       }
 468       break;
 469     }
 470     case Op_Proj: {
 471       // we are only interested in the oop result projection from a call
 472       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 473           n->in(0)->as_Call()->returns_pointer()) {
 474         add_local_var_and_edge(n, PointsToNode::NoEscape,
 475                                n->in(0), delayed_worklist);
 476       }
 477       break;
 478     }
 479     case Op_Rethrow: // Exception object escapes
 480     case Op_Return: {
 481       if (n->req() > TypeFunc::Parms &&
 482           igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 483         // Treat Return value as LocalVar with GlobalEscape escape state.
 484         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 485                                n->in(TypeFunc::Parms), delayed_worklist);
 486       }
 487       break;
 488     }
 489     case Op_GetAndSetP:
 490     case Op_GetAndSetN: {
 491       add_objload_to_connection_graph(n, delayed_worklist);
 492       // fallthrough
 493     }
 494     case Op_StoreP:
 495     case Op_StoreN:
 496     case Op_StoreNKlass:
 497     case Op_StorePConditional:
 498     case Op_CompareAndSwapP:
 499     case Op_CompareAndSwapN: {
 500       Node* adr = n->in(MemNode::Address);
 501       const Type *adr_type = igvn->type(adr);
 502       adr_type = adr_type->make_ptr();
 503       if (adr_type == NULL) {
 504         break; // skip dead nodes
 505       }
 506       if (adr_type->isa_oopptr() ||
 507           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
 508                         (adr_type == TypeRawPtr::NOTNULL &&
 509                          adr->in(AddPNode::Address)->is_Proj() &&
 510                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
 511         delayed_worklist->push(n); // Process it later.
 512 #ifdef ASSERT
 513         assert(adr->is_AddP(), "expecting an AddP");
 514         if (adr_type == TypeRawPtr::NOTNULL) {
 515           // Verify a raw address for a store captured by Initialize node.
 516           int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 517           assert(offs != Type::OffsetBot, "offset must be a constant");
 518         }
 519 #endif
 520       } else {
 521         // Ignore copy the displaced header to the BoxNode (OSR compilation).
 522         if (adr->is_BoxLock())
 523           break;
 524         // Stored value escapes in unsafe access.
 525         if ((opcode == Op_StoreP) && (adr_type == TypeRawPtr::BOTTOM)) {
 526           // Pointer stores in G1 barriers looks like unsafe access.
 527           // Ignore such stores to be able scalar replace non-escaping
 528           // allocations.
 529           if ((UseG1GC || UseShenandoahGC) && adr->is_AddP()) {
 530             Node* base = get_addp_base(adr);
 531             if (base->Opcode() == Op_LoadP &&
 532                 base->in(MemNode::Address)->is_AddP()) {
 533               adr = base->in(MemNode::Address);
 534               Node* tls = get_addp_base(adr);
 535               if (tls->Opcode() == Op_ThreadLocal) {
 536                 int offs = (int)igvn->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
 537                 if (offs == in_bytes(JavaThread::satb_mark_queue_offset() +
 538                                      PtrQueue::byte_offset_of_buf())) {
 539                   break; // G1 pre barier previous oop value store.
 540                 }
 541                 if (offs == in_bytes(JavaThread::dirty_card_queue_offset() +
 542                                      PtrQueue::byte_offset_of_buf())) {
 543                   break; // G1 post barier card address store.
 544                 }
 545               }
 546             }
 547           }
 548           delayed_worklist->push(n); // Process unsafe access later.
 549           break;
 550         }
 551 #ifdef ASSERT
 552         n->dump(1);
 553         assert(false, "not unsafe or G1 barrier raw StoreP");
 554 #endif
 555       }
 556       break;
 557     }
 558     case Op_AryEq:
 559     case Op_StrComp:
 560     case Op_StrEquals:
 561     case Op_StrIndexOf:
 562     case Op_EncodeISOArray: {
 563       add_local_var(n, PointsToNode::ArgEscape);
 564       delayed_worklist->push(n); // Process it later.
 565       break;
 566     }
 567     case Op_ThreadLocal: {
 568       add_java_object(n, PointsToNode::ArgEscape);
 569       break;
 570     }
 571 #if INCLUDE_ALL_GCS
 572     case Op_ShenandoahLoadReferenceBarrier:
 573       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(ShenandoahLoadReferenceBarrierNode::ValueIn), delayed_worklist);
 574       break;
 575 #endif
 576     default:
 577       ; // Do nothing for nodes not related to EA.
 578   }
 579   return;
 580 }
 581 
 582 #ifdef ASSERT
 583 #define ELSE_FAIL(name)                               \
 584       /* Should not be called for not pointer type. */  \
 585       n->dump(1);                                       \
 586       assert(false, name);                              \
 587       break;
 588 #else
 589 #define ELSE_FAIL(name) \
 590       break;
 591 #endif
 592 
 593 // Add final simple edges to graph.
 594 void ConnectionGraph::add_final_edges(Node *n) {
 595   PointsToNode* n_ptn = ptnode_adr(n->_idx);
 596 #ifdef ASSERT
 597   if (_verify && n_ptn->is_JavaObject())
 598     return; // This method does not change graph for JavaObject.
 599 #endif
 600 
 601   if (n->is_Call()) {
 602     process_call_arguments(n->as_Call());
 603     return;
 604   }
 605   assert(n->is_Store() || n->is_LoadStore() ||
 606          (n_ptn != NULL) && (n_ptn->ideal_node() != NULL),
 607          "node should be registered already");
 608   int opcode = n->Opcode();
 609   switch (opcode) {
 610     case Op_AddP: {
 611       Node* base = get_addp_base(n);
 612       PointsToNode* ptn_base = ptnode_adr(base->_idx);
 613       assert(ptn_base != NULL, "field's base should be registered");
 614       add_base(n_ptn->as_Field(), ptn_base);
 615       break;
 616     }
 617     case Op_CastPP:
 618     case Op_CheckCastPP:
 619     case Op_EncodeP:
 620     case Op_DecodeN:
 621     case Op_EncodePKlass:
 622     case Op_DecodeNKlass: {
 623       add_local_var_and_edge(n, PointsToNode::NoEscape,
 624                              n->in(1), NULL);
 625       break;
 626     }
 627     case Op_CMoveP: {
 628       for (uint i = CMoveNode::IfFalse; i < n->req(); i++) {
 629         Node* in = n->in(i);
 630         if (in == NULL)
 631           continue;  // ignore NULL
 632         Node* uncast_in = in->uncast();
 633         if (uncast_in->is_top() || uncast_in == n)
 634           continue;  // ignore top or inputs which go back this node
 635         PointsToNode* ptn = ptnode_adr(in->_idx);
 636         assert(ptn != NULL, "node should be registered");
 637         add_edge(n_ptn, ptn);
 638       }
 639       break;
 640     }
 641     case Op_LoadP:
 642     case Op_LoadN:
 643     case Op_LoadPLocked: {
 644       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 645       // ThreadLocal has RawPtr type.
 646       const Type* t = _igvn->type(n);
 647       if (t->make_ptr() != NULL) {
 648         Node* adr = n->in(MemNode::Address);
 649         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 650         break;
 651       }
 652       ELSE_FAIL("Op_LoadP");
 653     }
 654     case Op_Phi: {
 655       // Using isa_ptr() instead of isa_oopptr() for LoadP and Phi because
 656       // ThreadLocal has RawPtr type.
 657       const Type* t = n->as_Phi()->type();
 658       if (t->make_ptr() != NULL) {
 659         for (uint i = 1; i < n->req(); i++) {
 660           Node* in = n->in(i);
 661           if (in == NULL)
 662             continue;  // ignore NULL
 663           Node* uncast_in = in->uncast();
 664           if (uncast_in->is_top() || uncast_in == n)
 665             continue;  // ignore top or inputs which go back this node
 666           PointsToNode* ptn = ptnode_adr(in->_idx);
 667           assert(ptn != NULL, "node should be registered");
 668           add_edge(n_ptn, ptn);
 669         }
 670         break;
 671       }
 672       ELSE_FAIL("Op_Phi");
 673     }
 674     case Op_Proj: {
 675       // we are only interested in the oop result projection from a call
 676       if (n->as_Proj()->_con == TypeFunc::Parms && n->in(0)->is_Call() &&
 677           n->in(0)->as_Call()->returns_pointer()) {
 678         add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0), NULL);
 679         break;
 680       }
 681       ELSE_FAIL("Op_Proj");
 682     }
 683     case Op_Rethrow: // Exception object escapes
 684     case Op_Return: {
 685       if (n->req() > TypeFunc::Parms &&
 686           _igvn->type(n->in(TypeFunc::Parms))->isa_oopptr()) {
 687         // Treat Return value as LocalVar with GlobalEscape escape state.
 688         add_local_var_and_edge(n, PointsToNode::GlobalEscape,
 689                                n->in(TypeFunc::Parms), NULL);
 690         break;
 691       }
 692       ELSE_FAIL("Op_Return");
 693     }
 694     case Op_StoreP:
 695     case Op_StoreN:
 696     case Op_StoreNKlass:
 697     case Op_StorePConditional:
 698     case Op_CompareAndSwapP:
 699     case Op_CompareAndSwapN:
 700     case Op_GetAndSetP:
 701     case Op_GetAndSetN: {
 702       Node* adr = n->in(MemNode::Address);
 703       const Type *adr_type = _igvn->type(adr);
 704       adr_type = adr_type->make_ptr();
 705 #ifdef ASSERT
 706       if (adr_type == NULL) {
 707         n->dump(1);
 708         assert(adr_type != NULL, "dead node should not be on list");
 709         break;
 710       }
 711 #endif
 712       if (opcode == Op_GetAndSetP || opcode == Op_GetAndSetN) {
 713         add_local_var_and_edge(n, PointsToNode::NoEscape, adr, NULL);
 714       }
 715       if (adr_type->isa_oopptr() ||
 716           (opcode == Op_StoreP || opcode == Op_StoreN || opcode == Op_StoreNKlass) &&
 717                         (adr_type == TypeRawPtr::NOTNULL &&
 718                          adr->in(AddPNode::Address)->is_Proj() &&
 719                          adr->in(AddPNode::Address)->in(0)->is_Allocate())) {
 720         // Point Address to Value
 721         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 722         assert(adr_ptn != NULL &&
 723                adr_ptn->as_Field()->is_oop(), "node should be registered");
 724         Node *val = n->in(MemNode::ValueIn);
 725         PointsToNode* ptn = ptnode_adr(val->_idx);
 726         assert(ptn != NULL, "node should be registered");
 727         add_edge(adr_ptn, ptn);
 728         break;
 729       } else if ((opcode == Op_StoreP) && (adr_type == TypeRawPtr::BOTTOM)) {
 730         // Stored value escapes in unsafe access.
 731         Node *val = n->in(MemNode::ValueIn);
 732         PointsToNode* ptn = ptnode_adr(val->_idx);
 733         assert(ptn != NULL, "node should be registered");
 734         set_escape_state(ptn, PointsToNode::GlobalEscape);
 735         // Add edge to object for unsafe access with offset.
 736         PointsToNode* adr_ptn = ptnode_adr(adr->_idx);
 737         assert(adr_ptn != NULL, "node should be registered");
 738         if (adr_ptn->is_Field()) {
 739           assert(adr_ptn->as_Field()->is_oop(), "should be oop field");
 740           add_edge(adr_ptn, ptn);
 741         }
 742         break;
 743       }
 744       ELSE_FAIL("Op_StoreP");
 745     }
 746     case Op_AryEq:
 747     case Op_StrComp:
 748     case Op_StrEquals:
 749     case Op_StrIndexOf:
 750     case Op_EncodeISOArray: {
 751       // char[] arrays passed to string intrinsic do not escape but
 752       // they are not scalar replaceable. Adjust escape state for them.
 753       // Start from in(2) edge since in(1) is memory edge.
 754       for (uint i = 2; i < n->req(); i++) {
 755         Node* adr = n->in(i);
 756         const Type* at = _igvn->type(adr);
 757         if (!adr->is_top() && at->isa_ptr()) {
 758           assert(at == Type::TOP || at == TypePtr::NULL_PTR ||
 759                  at->isa_ptr() != NULL, "expecting a pointer");
 760           if (adr->is_AddP()) {
 761             adr = get_addp_base(adr);
 762           }
 763           PointsToNode* ptn = ptnode_adr(adr->_idx);
 764           assert(ptn != NULL, "node should be registered");
 765           add_edge(n_ptn, ptn);
 766         }
 767       }
 768       break;
 769     }
 770 #if INCLUDE_ALL_GCS
 771     case Op_ShenandoahLoadReferenceBarrier:
 772       add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(ShenandoahLoadReferenceBarrierNode::ValueIn), NULL);
 773       break;
 774 #endif
 775   default: {
 776       // This method should be called only for EA specific nodes which may
 777       // miss some edges when they were created.
 778 #ifdef ASSERT
 779       n->dump(1);
 780 #endif
 781       guarantee(false, "unknown node");
 782     }
 783   }
 784   return;
 785 }
 786 
 787 void ConnectionGraph::add_call_node(CallNode* call) {
 788   assert(call->returns_pointer(), "only for call which returns pointer");
 789   uint call_idx = call->_idx;
 790   if (call->is_Allocate()) {
 791     Node* k = call->in(AllocateNode::KlassNode);
 792     const TypeKlassPtr* kt = k->bottom_type()->isa_klassptr();
 793     assert(kt != NULL, "TypeKlassPtr  required.");
 794     ciKlass* cik = kt->klass();
 795     PointsToNode::EscapeState es = PointsToNode::NoEscape;
 796     bool scalar_replaceable = true;
 797     if (call->is_AllocateArray()) {
 798       if (!cik->is_array_klass()) { // StressReflectiveCode
 799         es = PointsToNode::GlobalEscape;
 800       } else {
 801         int length = call->in(AllocateNode::ALength)->find_int_con(-1);
 802         if (length < 0 || length > EliminateAllocationArraySizeLimit) {
 803           // Not scalar replaceable if the length is not constant or too big.
 804           scalar_replaceable = false;
 805         }
 806       }
 807     } else {  // Allocate instance
 808       if (cik->is_subclass_of(_compile->env()->Thread_klass()) ||
 809           cik->is_subclass_of(_compile->env()->Reference_klass()) ||
 810          !cik->is_instance_klass() || // StressReflectiveCode
 811           cik->as_instance_klass()->has_finalizer()) {
 812         es = PointsToNode::GlobalEscape;
 813       }
 814     }
 815     add_java_object(call, es);
 816     PointsToNode* ptn = ptnode_adr(call_idx);
 817     if (!scalar_replaceable && ptn->scalar_replaceable()) {
 818       ptn->set_scalar_replaceable(false);
 819     }
 820   } else if (call->is_CallStaticJava()) {
 821     // Call nodes could be different types:
 822     //
 823     // 1. CallDynamicJavaNode (what happened during call is unknown):
 824     //
 825     //    - mapped to GlobalEscape JavaObject node if oop is returned;
 826     //
 827     //    - all oop arguments are escaping globally;
 828     //
 829     // 2. CallStaticJavaNode (execute bytecode analysis if possible):
 830     //
 831     //    - the same as CallDynamicJavaNode if can't do bytecode analysis;
 832     //
 833     //    - mapped to GlobalEscape JavaObject node if unknown oop is returned;
 834     //    - mapped to NoEscape JavaObject node if non-escaping object allocated
 835     //      during call is returned;
 836     //    - mapped to ArgEscape LocalVar node pointed to object arguments
 837     //      which are returned and does not escape during call;
 838     //
 839     //    - oop arguments escaping status is defined by bytecode analysis;
 840     //
 841     // For a static call, we know exactly what method is being called.
 842     // Use bytecode estimator to record whether the call's return value escapes.
 843     ciMethod* meth = call->as_CallJava()->method();
 844     if (meth == NULL) {
 845       const char* name = call->as_CallStaticJava()->_name;
 846       assert(strncmp(name, "_multianewarray", 15) == 0, "TODO: add failed case check");
 847       // Returns a newly allocated unescaped object.
 848       add_java_object(call, PointsToNode::NoEscape);
 849       ptnode_adr(call_idx)->set_scalar_replaceable(false);
 850     } else if (meth->is_boxing_method()) {
 851       // Returns boxing object
 852       PointsToNode::EscapeState es;
 853       vmIntrinsics::ID intr = meth->intrinsic_id();
 854       if (intr == vmIntrinsics::_floatValue || intr == vmIntrinsics::_doubleValue) {
 855         // It does not escape if object is always allocated.
 856         es = PointsToNode::NoEscape;
 857       } else {
 858         // It escapes globally if object could be loaded from cache.
 859         es = PointsToNode::GlobalEscape;
 860       }
 861       add_java_object(call, es);
 862     } else {
 863       BCEscapeAnalyzer* call_analyzer = meth->get_bcea();
 864       call_analyzer->copy_dependencies(_compile->dependencies());
 865       if (call_analyzer->is_return_allocated()) {
 866         // Returns a newly allocated unescaped object, simply
 867         // update dependency information.
 868         // Mark it as NoEscape so that objects referenced by
 869         // it's fields will be marked as NoEscape at least.
 870         add_java_object(call, PointsToNode::NoEscape);
 871         ptnode_adr(call_idx)->set_scalar_replaceable(false);
 872       } else {
 873         // Determine whether any arguments are returned.
 874         const TypeTuple* d = call->tf()->domain();
 875         bool ret_arg = false;
 876         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 877           if (d->field_at(i)->isa_ptr() != NULL &&
 878               call_analyzer->is_arg_returned(i - TypeFunc::Parms)) {
 879             ret_arg = true;
 880             break;
 881           }
 882         }
 883         if (ret_arg) {
 884           add_local_var(call, PointsToNode::ArgEscape);
 885         } else {
 886           // Returns unknown object.
 887           map_ideal_node(call, phantom_obj);
 888         }
 889       }
 890     }
 891   } else {
 892     // An other type of call, assume the worst case:
 893     // returned value is unknown and globally escapes.
 894     assert(call->Opcode() == Op_CallDynamicJava, "add failed case check");
 895     map_ideal_node(call, phantom_obj);
 896   }
 897 }
 898 
 899 void ConnectionGraph::process_call_arguments(CallNode *call) {
 900     bool is_arraycopy = false;
 901     switch (call->Opcode()) {
 902 #ifdef ASSERT
 903     case Op_Allocate:
 904     case Op_AllocateArray:
 905     case Op_Lock:
 906     case Op_Unlock:
 907       assert(false, "should be done already");
 908       break;
 909 #endif
 910     case Op_CallLeafNoFP:
 911       is_arraycopy = (call->as_CallLeaf()->_name != NULL &&
 912                       strstr(call->as_CallLeaf()->_name, "arraycopy") != 0);
 913       // fall through
 914     case Op_CallLeaf: {
 915       // Stub calls, objects do not escape but they are not scale replaceable.
 916       // Adjust escape state for outgoing arguments.
 917       const TypeTuple * d = call->tf()->domain();
 918       bool src_has_oops = false;
 919       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
 920         const Type* at = d->field_at(i);
 921         Node *arg = call->in(i);
 922         const Type *aat = _igvn->type(arg);
 923         if (arg->is_top() || !at->isa_ptr() || !aat->isa_ptr())
 924           continue;
 925         if (arg->is_AddP()) {
 926           //
 927           // The inline_native_clone() case when the arraycopy stub is called
 928           // after the allocation before Initialize and CheckCastPP nodes.
 929           // Or normal arraycopy for object arrays case.
 930           //
 931           // Set AddP's base (Allocate) as not scalar replaceable since
 932           // pointer to the base (with offset) is passed as argument.
 933           //
 934           arg = get_addp_base(arg);
 935         }
 936         PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
 937         assert(arg_ptn != NULL, "should be registered");
 938         PointsToNode::EscapeState arg_esc = arg_ptn->escape_state();
 939         if (is_arraycopy || arg_esc < PointsToNode::ArgEscape) {
 940           assert(aat == Type::TOP || aat == TypePtr::NULL_PTR ||
 941                  aat->isa_ptr() != NULL, "expecting an Ptr");
 942           bool arg_has_oops = aat->isa_oopptr() &&
 943                               (aat->isa_oopptr()->klass() == NULL || aat->isa_instptr() ||
 944                                (aat->isa_aryptr() && aat->isa_aryptr()->klass()->is_obj_array_klass()));
 945           if (i == TypeFunc::Parms) {
 946             src_has_oops = arg_has_oops;
 947           }
 948           //
 949           // src or dst could be j.l.Object when other is basic type array:
 950           //
 951           //   arraycopy(char[],0,Object*,0,size);
 952           //   arraycopy(Object*,0,char[],0,size);
 953           //
 954           // Don't add edges in such cases.
 955           //
 956           bool arg_is_arraycopy_dest = src_has_oops && is_arraycopy &&
 957                                        arg_has_oops && (i > TypeFunc::Parms);
 958 #ifdef ASSERT
 959           if (!(is_arraycopy ||
 960                 (call->as_CallLeaf()->_name != NULL &&
 961                  (strcmp(call->as_CallLeaf()->_name, "g1_wb_pre")  == 0 ||
 962                   strcmp(call->as_CallLeaf()->_name, "g1_wb_post") == 0 ||
 963                   strcmp(call->as_CallLeaf()->_name, "shenandoah_clone_barrier")  == 0 ||
 964                   strcmp(call->as_CallLeaf()->_name, "shenandoah_cas_obj")  == 0 ||
 965                   strcmp(call->as_CallLeaf()->_name, "updateBytesCRC32") == 0 ||
 966                   strcmp(call->as_CallLeaf()->_name, "aescrypt_encryptBlock") == 0 ||
 967                   strcmp(call->as_CallLeaf()->_name, "aescrypt_decryptBlock") == 0 ||
 968                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_encryptAESCrypt") == 0 ||
 969                   strcmp(call->as_CallLeaf()->_name, "cipherBlockChaining_decryptAESCrypt") == 0 ||
 970                   strcmp(call->as_CallLeaf()->_name, "ghash_processBlocks") == 0 ||
 971                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompress") == 0 ||
 972                   strcmp(call->as_CallLeaf()->_name, "sha1_implCompressMB") == 0 ||
 973                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompress") == 0 ||
 974                   strcmp(call->as_CallLeaf()->_name, "sha256_implCompressMB") == 0 ||
 975                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompress") == 0 ||
 976                   strcmp(call->as_CallLeaf()->_name, "sha512_implCompressMB") == 0 ||
 977                   strcmp(call->as_CallLeaf()->_name, "multiplyToLen") == 0 ||
 978                   strcmp(call->as_CallLeaf()->_name, "squareToLen") == 0 ||
 979                   strcmp(call->as_CallLeaf()->_name, "mulAdd") == 0 ||
 980                   strcmp(call->as_CallLeaf()->_name, "montgomery_multiply") == 0 ||
 981                   strcmp(call->as_CallLeaf()->_name, "montgomery_square") == 0)
 982                  ))) {
 983             call->dump();
 984             fatal(err_msg_res("EA unexpected CallLeaf %s", call->as_CallLeaf()->_name));
 985           }
 986 #endif
 987           // Always process arraycopy's destination object since
 988           // we need to add all possible edges to references in
 989           // source object.
 990           if (arg_esc >= PointsToNode::ArgEscape &&
 991               !arg_is_arraycopy_dest) {
 992             continue;
 993           }
 994           set_escape_state(arg_ptn, PointsToNode::ArgEscape);
 995           if (arg_is_arraycopy_dest) {
 996             Node* src = call->in(TypeFunc::Parms);
 997             if (src->is_AddP()) {
 998               src = get_addp_base(src);
 999             }
1000             PointsToNode* src_ptn = ptnode_adr(src->_idx);
1001             assert(src_ptn != NULL, "should be registered");
1002             if (arg_ptn != src_ptn) {
1003               // Special arraycopy edge:
1004               // A destination object's field can't have the source object
1005               // as base since objects escape states are not related.
1006               // Only escape state of destination object's fields affects
1007               // escape state of fields in source object.
1008               add_arraycopy(call, PointsToNode::ArgEscape, src_ptn, arg_ptn);
1009             }
1010           }
1011         }
1012       }
1013       break;
1014     }
1015     case Op_CallStaticJava: {
1016       // For a static call, we know exactly what method is being called.
1017       // Use bytecode estimator to record the call's escape affects
1018 #ifdef ASSERT
1019       const char* name = call->as_CallStaticJava()->_name;
1020       assert((name == NULL || strcmp(name, "uncommon_trap") != 0), "normal calls only");
1021 #endif
1022       ciMethod* meth = call->as_CallJava()->method();
1023       if ((meth != NULL) && meth->is_boxing_method()) {
1024         break; // Boxing methods do not modify any oops.
1025       }
1026       BCEscapeAnalyzer* call_analyzer = (meth !=NULL) ? meth->get_bcea() : NULL;
1027       // fall-through if not a Java method or no analyzer information
1028       if (call_analyzer != NULL) {
1029         PointsToNode* call_ptn = ptnode_adr(call->_idx);
1030         const TypeTuple* d = call->tf()->domain();
1031         for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1032           const Type* at = d->field_at(i);
1033           int k = i - TypeFunc::Parms;
1034           Node* arg = call->in(i);
1035           PointsToNode* arg_ptn = ptnode_adr(arg->_idx);
1036           if (at->isa_ptr() != NULL &&
1037               call_analyzer->is_arg_returned(k)) {
1038             // The call returns arguments.
1039             if (call_ptn != NULL) { // Is call's result used?
1040               assert(call_ptn->is_LocalVar(), "node should be registered");
1041               assert(arg_ptn != NULL, "node should be registered");
1042               add_edge(call_ptn, arg_ptn);
1043             }
1044           }
1045           if (at->isa_oopptr() != NULL &&
1046               arg_ptn->escape_state() < PointsToNode::GlobalEscape) {
1047             if (!call_analyzer->is_arg_stack(k)) {
1048               // The argument global escapes
1049               set_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1050             } else {
1051               set_escape_state(arg_ptn, PointsToNode::ArgEscape);
1052               if (!call_analyzer->is_arg_local(k)) {
1053                 // The argument itself doesn't escape, but any fields might
1054                 set_fields_escape_state(arg_ptn, PointsToNode::GlobalEscape);
1055               }
1056             }
1057           }
1058         }
1059         if (call_ptn != NULL && call_ptn->is_LocalVar()) {
1060           // The call returns arguments.
1061           assert(call_ptn->edge_count() > 0, "sanity");
1062           if (!call_analyzer->is_return_local()) {
1063             // Returns also unknown object.
1064             add_edge(call_ptn, phantom_obj);
1065           }
1066         }
1067         break;
1068       }
1069     }
1070     default: {
1071       // Fall-through here if not a Java method or no analyzer information
1072       // or some other type of call, assume the worst case: all arguments
1073       // globally escape.
1074       const TypeTuple* d = call->tf()->domain();
1075       for (uint i = TypeFunc::Parms; i < d->cnt(); i++) {
1076         const Type* at = d->field_at(i);
1077         if (at->isa_oopptr() != NULL) {
1078           Node* arg = call->in(i);
1079           if (arg->is_AddP()) {
1080             arg = get_addp_base(arg);
1081           }
1082           assert(ptnode_adr(arg->_idx) != NULL, "should be defined already");
1083           set_escape_state(ptnode_adr(arg->_idx), PointsToNode::GlobalEscape);
1084         }
1085       }
1086     }
1087   }
1088 }
1089 
1090 
1091 // Finish Graph construction.
1092 bool ConnectionGraph::complete_connection_graph(
1093                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1094                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1095                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1096                          GrowableArray<FieldNode*>&      oop_fields_worklist) {
1097   // Normally only 1-3 passes needed to build Connection Graph depending
1098   // on graph complexity. Observed 8 passes in jvm2008 compiler.compiler.
1099   // Set limit to 20 to catch situation when something did go wrong and
1100   // bailout Escape Analysis.
1101   // Also limit build time to 20 sec (60 in debug VM), EscapeAnalysisTimeout flag.
1102 #define CG_BUILD_ITER_LIMIT 20
1103 
1104   // Propagate GlobalEscape and ArgEscape escape states and check that
1105   // we still have non-escaping objects. The method pushs on _worklist
1106   // Field nodes which reference phantom_object.
1107   if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1108     return false; // Nothing to do.
1109   }
1110   // Now propagate references to all JavaObject nodes.
1111   int java_objects_length = java_objects_worklist.length();
1112   elapsedTimer time;
1113   bool timeout = false;
1114   int new_edges = 1;
1115   int iterations = 0;
1116   do {
1117     while ((new_edges > 0) &&
1118            (iterations++ < CG_BUILD_ITER_LIMIT)) {
1119       double start_time = time.seconds();
1120       time.start();
1121       new_edges = 0;
1122       // Propagate references to phantom_object for nodes pushed on _worklist
1123       // by find_non_escaped_objects() and find_field_value().
1124       new_edges += add_java_object_edges(phantom_obj, false);
1125       for (int next = 0; next < java_objects_length; ++next) {
1126         JavaObjectNode* ptn = java_objects_worklist.at(next);
1127         new_edges += add_java_object_edges(ptn, true);
1128 
1129 #define SAMPLE_SIZE 4
1130         if ((next % SAMPLE_SIZE) == 0) {
1131           // Each 4 iterations calculate how much time it will take
1132           // to complete graph construction.
1133           time.stop();
1134           // Poll for requests from shutdown mechanism to quiesce compiler
1135           // because Connection graph construction may take long time.
1136           CompileBroker::maybe_block();
1137           double stop_time = time.seconds();
1138           double time_per_iter = (stop_time - start_time) / (double)SAMPLE_SIZE;
1139           double time_until_end = time_per_iter * (double)(java_objects_length - next);
1140           if ((start_time + time_until_end) >= EscapeAnalysisTimeout) {
1141             timeout = true;
1142             break; // Timeout
1143           }
1144           start_time = stop_time;
1145           time.start();
1146         }
1147 #undef SAMPLE_SIZE
1148 
1149       }
1150       if (timeout) break;
1151       if (new_edges > 0) {
1152         // Update escape states on each iteration if graph was updated.
1153         if (!find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist)) {
1154           return false; // Nothing to do.
1155         }
1156       }
1157       time.stop();
1158       if (time.seconds() >= EscapeAnalysisTimeout) {
1159         timeout = true;
1160         break;
1161       }
1162     }
1163     if ((iterations < CG_BUILD_ITER_LIMIT) && !timeout) {
1164       time.start();
1165       // Find fields which have unknown value.
1166       int fields_length = oop_fields_worklist.length();
1167       for (int next = 0; next < fields_length; next++) {
1168         FieldNode* field = oop_fields_worklist.at(next);
1169         if (field->edge_count() == 0) {
1170           new_edges += find_field_value(field);
1171           // This code may added new edges to phantom_object.
1172           // Need an other cycle to propagate references to phantom_object.
1173         }
1174       }
1175       time.stop();
1176       if (time.seconds() >= EscapeAnalysisTimeout) {
1177         timeout = true;
1178         break;
1179       }
1180     } else {
1181       new_edges = 0; // Bailout
1182     }
1183   } while (new_edges > 0);
1184 
1185   // Bailout if passed limits.
1186   if ((iterations >= CG_BUILD_ITER_LIMIT) || timeout) {
1187     Compile* C = _compile;
1188     if (C->log() != NULL) {
1189       C->log()->begin_elem("connectionGraph_bailout reason='reached ");
1190       C->log()->text("%s", timeout ? "time" : "iterations");
1191       C->log()->end_elem(" limit'");
1192     }
1193     assert(ExitEscapeAnalysisOnTimeout, err_msg_res("infinite EA connection graph build (%f sec, %d iterations) with %d nodes and worklist size %d",
1194            time.seconds(), iterations, nodes_size(), ptnodes_worklist.length()));
1195     // Possible infinite build_connection_graph loop,
1196     // bailout (no changes to ideal graph were made).
1197     return false;
1198   }
1199 #ifdef ASSERT
1200   if (Verbose && PrintEscapeAnalysis) {
1201     tty->print_cr("EA: %d iterations to build connection graph with %d nodes and worklist size %d",
1202                   iterations, nodes_size(), ptnodes_worklist.length());
1203   }
1204 #endif
1205 
1206 #undef CG_BUILD_ITER_LIMIT
1207 
1208   // Find fields initialized by NULL for non-escaping Allocations.
1209   int non_escaped_length = non_escaped_worklist.length();
1210   for (int next = 0; next < non_escaped_length; next++) {
1211     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1212     PointsToNode::EscapeState es = ptn->escape_state();
1213     assert(es <= PointsToNode::ArgEscape, "sanity");
1214     if (es == PointsToNode::NoEscape) {
1215       if (find_init_values(ptn, null_obj, _igvn) > 0) {
1216         // Adding references to NULL object does not change escape states
1217         // since it does not escape. Also no fields are added to NULL object.
1218         add_java_object_edges(null_obj, false);
1219       }
1220     }
1221     Node* n = ptn->ideal_node();
1222     if (n->is_Allocate()) {
1223       // The object allocated by this Allocate node will never be
1224       // seen by an other thread. Mark it so that when it is
1225       // expanded no MemBarStoreStore is added.
1226       InitializeNode* ini = n->as_Allocate()->initialization();
1227       if (ini != NULL)
1228         ini->set_does_not_escape();
1229     }
1230   }
1231   return true; // Finished graph construction.
1232 }
1233 
1234 // Propagate GlobalEscape and ArgEscape escape states to all nodes
1235 // and check that we still have non-escaping java objects.
1236 bool ConnectionGraph::find_non_escaped_objects(GrowableArray<PointsToNode*>& ptnodes_worklist,
1237                                                GrowableArray<JavaObjectNode*>& non_escaped_worklist) {
1238   GrowableArray<PointsToNode*> escape_worklist;
1239   // First, put all nodes with GlobalEscape and ArgEscape states on worklist.
1240   int ptnodes_length = ptnodes_worklist.length();
1241   for (int next = 0; next < ptnodes_length; ++next) {
1242     PointsToNode* ptn = ptnodes_worklist.at(next);
1243     if (ptn->escape_state() >= PointsToNode::ArgEscape ||
1244         ptn->fields_escape_state() >= PointsToNode::ArgEscape) {
1245       escape_worklist.push(ptn);
1246     }
1247   }
1248   // Set escape states to referenced nodes (edges list).
1249   while (escape_worklist.length() > 0) {
1250     PointsToNode* ptn = escape_worklist.pop();
1251     PointsToNode::EscapeState es  = ptn->escape_state();
1252     PointsToNode::EscapeState field_es = ptn->fields_escape_state();
1253     if (ptn->is_Field() && ptn->as_Field()->is_oop() &&
1254         es >= PointsToNode::ArgEscape) {
1255       // GlobalEscape or ArgEscape state of field means it has unknown value.
1256       if (add_edge(ptn, phantom_obj)) {
1257         // New edge was added
1258         add_field_uses_to_worklist(ptn->as_Field());
1259       }
1260     }
1261     for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1262       PointsToNode* e = i.get();
1263       if (e->is_Arraycopy()) {
1264         assert(ptn->arraycopy_dst(), "sanity");
1265         // Propagate only fields escape state through arraycopy edge.
1266         if (e->fields_escape_state() < field_es) {
1267           set_fields_escape_state(e, field_es);
1268           escape_worklist.push(e);
1269         }
1270       } else if (es >= field_es) {
1271         // fields_escape_state is also set to 'es' if it is less than 'es'.
1272         if (e->escape_state() < es) {
1273           set_escape_state(e, es);
1274           escape_worklist.push(e);
1275         }
1276       } else {
1277         // Propagate field escape state.
1278         bool es_changed = false;
1279         if (e->fields_escape_state() < field_es) {
1280           set_fields_escape_state(e, field_es);
1281           es_changed = true;
1282         }
1283         if ((e->escape_state() < field_es) &&
1284             e->is_Field() && ptn->is_JavaObject() &&
1285             e->as_Field()->is_oop()) {
1286           // Change escape state of referenced fileds.
1287           set_escape_state(e, field_es);
1288           es_changed = true;;
1289         } else if (e->escape_state() < es) {
1290           set_escape_state(e, es);
1291           es_changed = true;;
1292         }
1293         if (es_changed) {
1294           escape_worklist.push(e);
1295         }
1296       }
1297     }
1298   }
1299   // Remove escaped objects from non_escaped list.
1300   for (int next = non_escaped_worklist.length()-1; next >= 0 ; --next) {
1301     JavaObjectNode* ptn = non_escaped_worklist.at(next);
1302     if (ptn->escape_state() >= PointsToNode::GlobalEscape) {
1303       non_escaped_worklist.delete_at(next);
1304     }
1305     if (ptn->escape_state() == PointsToNode::NoEscape) {
1306       // Find fields in non-escaped allocations which have unknown value.
1307       find_init_values(ptn, phantom_obj, NULL);
1308     }
1309   }
1310   return (non_escaped_worklist.length() > 0);
1311 }
1312 
1313 // Add all references to JavaObject node by walking over all uses.
1314 int ConnectionGraph::add_java_object_edges(JavaObjectNode* jobj, bool populate_worklist) {
1315   int new_edges = 0;
1316   if (populate_worklist) {
1317     // Populate _worklist by uses of jobj's uses.
1318     for (UseIterator i(jobj); i.has_next(); i.next()) {
1319       PointsToNode* use = i.get();
1320       if (use->is_Arraycopy())
1321         continue;
1322       add_uses_to_worklist(use);
1323       if (use->is_Field() && use->as_Field()->is_oop()) {
1324         // Put on worklist all field's uses (loads) and
1325         // related field nodes (same base and offset).
1326         add_field_uses_to_worklist(use->as_Field());
1327       }
1328     }
1329   }
1330   for (int l = 0; l < _worklist.length(); l++) {
1331     PointsToNode* use = _worklist.at(l);
1332     if (PointsToNode::is_base_use(use)) {
1333       // Add reference from jobj to field and from field to jobj (field's base).
1334       use = PointsToNode::get_use_node(use)->as_Field();
1335       if (add_base(use->as_Field(), jobj)) {
1336         new_edges++;
1337       }
1338       continue;
1339     }
1340     assert(!use->is_JavaObject(), "sanity");
1341     if (use->is_Arraycopy()) {
1342       if (jobj == null_obj) // NULL object does not have field edges
1343         continue;
1344       // Added edge from Arraycopy node to arraycopy's source java object
1345       if (add_edge(use, jobj)) {
1346         jobj->set_arraycopy_src();
1347         new_edges++;
1348       }
1349       // and stop here.
1350       continue;
1351     }
1352     if (!add_edge(use, jobj))
1353       continue; // No new edge added, there was such edge already.
1354     new_edges++;
1355     if (use->is_LocalVar()) {
1356       add_uses_to_worklist(use);
1357       if (use->arraycopy_dst()) {
1358         for (EdgeIterator i(use); i.has_next(); i.next()) {
1359           PointsToNode* e = i.get();
1360           if (e->is_Arraycopy()) {
1361             if (jobj == null_obj) // NULL object does not have field edges
1362               continue;
1363             // Add edge from arraycopy's destination java object to Arraycopy node.
1364             if (add_edge(jobj, e)) {
1365               new_edges++;
1366               jobj->set_arraycopy_dst();
1367             }
1368           }
1369         }
1370       }
1371     } else {
1372       // Added new edge to stored in field values.
1373       // Put on worklist all field's uses (loads) and
1374       // related field nodes (same base and offset).
1375       add_field_uses_to_worklist(use->as_Field());
1376     }
1377   }
1378   _worklist.clear();
1379   _in_worklist.Reset();
1380   return new_edges;
1381 }
1382 
1383 // Put on worklist all related field nodes.
1384 void ConnectionGraph::add_field_uses_to_worklist(FieldNode* field) {
1385   assert(field->is_oop(), "sanity");
1386   int offset = field->offset();
1387   add_uses_to_worklist(field);
1388   // Loop over all bases of this field and push on worklist Field nodes
1389   // with the same offset and base (since they may reference the same field).
1390   for (BaseIterator i(field); i.has_next(); i.next()) {
1391     PointsToNode* base = i.get();
1392     add_fields_to_worklist(field, base);
1393     // Check if the base was source object of arraycopy and go over arraycopy's
1394     // destination objects since values stored to a field of source object are
1395     // accessable by uses (loads) of fields of destination objects.
1396     if (base->arraycopy_src()) {
1397       for (UseIterator j(base); j.has_next(); j.next()) {
1398         PointsToNode* arycp = j.get();
1399         if (arycp->is_Arraycopy()) {
1400           for (UseIterator k(arycp); k.has_next(); k.next()) {
1401             PointsToNode* abase = k.get();
1402             if (abase->arraycopy_dst() && abase != base) {
1403               // Look for the same arracopy reference.
1404               add_fields_to_worklist(field, abase);
1405             }
1406           }
1407         }
1408       }
1409     }
1410   }
1411 }
1412 
1413 // Put on worklist all related field nodes.
1414 void ConnectionGraph::add_fields_to_worklist(FieldNode* field, PointsToNode* base) {
1415   int offset = field->offset();
1416   if (base->is_LocalVar()) {
1417     for (UseIterator j(base); j.has_next(); j.next()) {
1418       PointsToNode* f = j.get();
1419       if (PointsToNode::is_base_use(f)) { // Field
1420         f = PointsToNode::get_use_node(f);
1421         if (f == field || !f->as_Field()->is_oop())
1422           continue;
1423         int offs = f->as_Field()->offset();
1424         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1425           add_to_worklist(f);
1426         }
1427       }
1428     }
1429   } else {
1430     assert(base->is_JavaObject(), "sanity");
1431     if (// Skip phantom_object since it is only used to indicate that
1432         // this field's content globally escapes.
1433         (base != phantom_obj) &&
1434         // NULL object node does not have fields.
1435         (base != null_obj)) {
1436       for (EdgeIterator i(base); i.has_next(); i.next()) {
1437         PointsToNode* f = i.get();
1438         // Skip arraycopy edge since store to destination object field
1439         // does not update value in source object field.
1440         if (f->is_Arraycopy()) {
1441           assert(base->arraycopy_dst(), "sanity");
1442           continue;
1443         }
1444         if (f == field || !f->as_Field()->is_oop())
1445           continue;
1446         int offs = f->as_Field()->offset();
1447         if (offs == offset || offset == Type::OffsetBot || offs == Type::OffsetBot) {
1448           add_to_worklist(f);
1449         }
1450       }
1451     }
1452   }
1453 }
1454 
1455 // Find fields which have unknown value.
1456 int ConnectionGraph::find_field_value(FieldNode* field) {
1457   // Escaped fields should have init value already.
1458   assert(field->escape_state() == PointsToNode::NoEscape, "sanity");
1459   int new_edges = 0;
1460   for (BaseIterator i(field); i.has_next(); i.next()) {
1461     PointsToNode* base = i.get();
1462     if (base->is_JavaObject()) {
1463       // Skip Allocate's fields which will be processed later.
1464       if (base->ideal_node()->is_Allocate())
1465         return 0;
1466       assert(base == null_obj, "only NULL ptr base expected here");
1467     }
1468   }
1469   if (add_edge(field, phantom_obj)) {
1470     // New edge was added
1471     new_edges++;
1472     add_field_uses_to_worklist(field);
1473   }
1474   return new_edges;
1475 }
1476 
1477 // Find fields initializing values for allocations.
1478 int ConnectionGraph::find_init_values(JavaObjectNode* pta, PointsToNode* init_val, PhaseTransform* phase) {
1479   assert(pta->escape_state() == PointsToNode::NoEscape, "Not escaped Allocate nodes only");
1480   int new_edges = 0;
1481   Node* alloc = pta->ideal_node();
1482   if (init_val == phantom_obj) {
1483     // Do nothing for Allocate nodes since its fields values are "known".
1484     if (alloc->is_Allocate())
1485       return 0;
1486     assert(alloc->as_CallStaticJava(), "sanity");
1487 #ifdef ASSERT
1488     if (alloc->as_CallStaticJava()->method() == NULL) {
1489       const char* name = alloc->as_CallStaticJava()->_name;
1490       assert(strncmp(name, "_multianewarray", 15) == 0, "sanity");
1491     }
1492 #endif
1493     // Non-escaped allocation returned from Java or runtime call have
1494     // unknown values in fields.
1495     for (EdgeIterator i(pta); i.has_next(); i.next()) {
1496       PointsToNode* field = i.get();
1497       if (field->is_Field() && field->as_Field()->is_oop()) {
1498         if (add_edge(field, phantom_obj)) {
1499           // New edge was added
1500           new_edges++;
1501           add_field_uses_to_worklist(field->as_Field());
1502         }
1503       }
1504     }
1505     return new_edges;
1506   }
1507   assert(init_val == null_obj, "sanity");
1508   // Do nothing for Call nodes since its fields values are unknown.
1509   if (!alloc->is_Allocate())
1510     return 0;
1511 
1512   InitializeNode* ini = alloc->as_Allocate()->initialization();
1513   Compile* C = _compile;
1514   bool visited_bottom_offset = false;
1515   GrowableArray<int> offsets_worklist;
1516 
1517   // Check if an oop field's initializing value is recorded and add
1518   // a corresponding NULL if field's value if it is not recorded.
1519   // Connection Graph does not record a default initialization by NULL
1520   // captured by Initialize node.
1521   //
1522   for (EdgeIterator i(pta); i.has_next(); i.next()) {
1523     PointsToNode* field = i.get(); // Field (AddP)
1524     if (!field->is_Field() || !field->as_Field()->is_oop())
1525       continue; // Not oop field
1526     int offset = field->as_Field()->offset();
1527     if (offset == Type::OffsetBot) {
1528       if (!visited_bottom_offset) {
1529         // OffsetBot is used to reference array's element,
1530         // always add reference to NULL to all Field nodes since we don't
1531         // known which element is referenced.
1532         if (add_edge(field, null_obj)) {
1533           // New edge was added
1534           new_edges++;
1535           add_field_uses_to_worklist(field->as_Field());
1536           visited_bottom_offset = true;
1537         }
1538       }
1539     } else {
1540       // Check only oop fields.
1541       const Type* adr_type = field->ideal_node()->as_AddP()->bottom_type();
1542       if (adr_type->isa_rawptr()) {
1543 #ifdef ASSERT
1544         // Raw pointers are used for initializing stores so skip it
1545         // since it should be recorded already
1546         Node* base = get_addp_base(field->ideal_node());
1547         assert(adr_type->isa_rawptr() && base->is_Proj() &&
1548                (base->in(0) == alloc),"unexpected pointer type");
1549 #endif
1550         continue;
1551       }
1552       if (!offsets_worklist.contains(offset)) {
1553         offsets_worklist.append(offset);
1554         Node* value = NULL;
1555         if (ini != NULL) {
1556           // StoreP::memory_type() == T_ADDRESS
1557           BasicType ft = UseCompressedOops ? T_NARROWOOP : T_ADDRESS;
1558           Node* store = ini->find_captured_store(offset, type2aelembytes(ft, true), phase);
1559           // Make sure initializing store has the same type as this AddP.
1560           // This AddP may reference non existing field because it is on a
1561           // dead branch of bimorphic call which is not eliminated yet.
1562           if (store != NULL && store->is_Store() &&
1563               store->as_Store()->memory_type() == ft) {
1564             value = store->in(MemNode::ValueIn);
1565 #ifdef ASSERT
1566             if (VerifyConnectionGraph) {
1567               // Verify that AddP already points to all objects the value points to.
1568               PointsToNode* val = ptnode_adr(value->_idx);
1569               assert((val != NULL), "should be processed already");
1570               PointsToNode* missed_obj = NULL;
1571               if (val->is_JavaObject()) {
1572                 if (!field->points_to(val->as_JavaObject())) {
1573                   missed_obj = val;
1574                 }
1575               } else {
1576                 if (!val->is_LocalVar() || (val->edge_count() == 0)) {
1577                   tty->print_cr("----------init store has invalid value -----");
1578                   store->dump();
1579                   val->dump();
1580                   assert(val->is_LocalVar() && (val->edge_count() > 0), "should be processed already");
1581                 }
1582                 for (EdgeIterator j(val); j.has_next(); j.next()) {
1583                   PointsToNode* obj = j.get();
1584                   if (obj->is_JavaObject()) {
1585                     if (!field->points_to(obj->as_JavaObject())) {
1586                       missed_obj = obj;
1587                       break;
1588                     }
1589                   }
1590                 }
1591               }
1592               if (missed_obj != NULL) {
1593                 tty->print_cr("----------field---------------------------------");
1594                 field->dump();
1595                 tty->print_cr("----------missed referernce to object-----------");
1596                 missed_obj->dump();
1597                 tty->print_cr("----------object referernced by init store -----");
1598                 store->dump();
1599                 val->dump();
1600                 assert(!field->points_to(missed_obj->as_JavaObject()), "missed JavaObject reference");
1601               }
1602             }
1603 #endif
1604           } else {
1605             // There could be initializing stores which follow allocation.
1606             // For example, a volatile field store is not collected
1607             // by Initialize node.
1608             //
1609             // Need to check for dependent loads to separate such stores from
1610             // stores which follow loads. For now, add initial value NULL so
1611             // that compare pointers optimization works correctly.
1612           }
1613         }
1614         if (value == NULL) {
1615           // A field's initializing value was not recorded. Add NULL.
1616           if (add_edge(field, null_obj)) {
1617             // New edge was added
1618             new_edges++;
1619             add_field_uses_to_worklist(field->as_Field());
1620           }
1621         }
1622       }
1623     }
1624   }
1625   return new_edges;
1626 }
1627 
1628 // Adjust scalar_replaceable state after Connection Graph is built.
1629 void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
1630   // Search for non-escaping objects which are not scalar replaceable
1631   // and mark them to propagate the state to referenced objects.
1632 
1633   // 1. An object is not scalar replaceable if the field into which it is
1634   // stored has unknown offset (stored into unknown element of an array).
1635   //
1636   for (UseIterator i(jobj); i.has_next(); i.next()) {
1637     PointsToNode* use = i.get();
1638     assert(!use->is_Arraycopy(), "sanity");
1639     if (use->is_Field()) {
1640       FieldNode* field = use->as_Field();
1641       assert(field->is_oop() && field->scalar_replaceable() &&
1642              field->fields_escape_state() == PointsToNode::NoEscape, "sanity");
1643       if (field->offset() == Type::OffsetBot) {
1644         jobj->set_scalar_replaceable(false);
1645         return;
1646       }
1647       // 2. An object is not scalar replaceable if the field into which it is
1648       // stored has multiple bases one of which is null.
1649       if (field->base_count() > 1) {
1650         for (BaseIterator i(field); i.has_next(); i.next()) {
1651           PointsToNode* base = i.get();
1652           if (base == null_obj) {
1653             jobj->set_scalar_replaceable(false);
1654             return;
1655           }
1656         }
1657       }
1658     }
1659     assert(use->is_Field() || use->is_LocalVar(), "sanity");
1660     // 3. An object is not scalar replaceable if it is merged with other objects.
1661     for (EdgeIterator j(use); j.has_next(); j.next()) {
1662       PointsToNode* ptn = j.get();
1663       if (ptn->is_JavaObject() && ptn != jobj) {
1664         // Mark all objects.
1665         jobj->set_scalar_replaceable(false);
1666          ptn->set_scalar_replaceable(false);
1667       }
1668     }
1669     if (!jobj->scalar_replaceable()) {
1670       return;
1671     }
1672   }
1673 
1674   for (EdgeIterator j(jobj); j.has_next(); j.next()) {
1675     // Non-escaping object node should point only to field nodes.
1676     FieldNode* field = j.get()->as_Field();
1677     int offset = field->as_Field()->offset();
1678 
1679     // 4. An object is not scalar replaceable if it has a field with unknown
1680     // offset (array's element is accessed in loop).
1681     if (offset == Type::OffsetBot) {
1682       jobj->set_scalar_replaceable(false);
1683       return;
1684     }
1685     // 5. Currently an object is not scalar replaceable if a LoadStore node
1686     // access its field since the field value is unknown after it.
1687     //
1688     Node* n = field->ideal_node();
1689     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1690       if (n->fast_out(i)->is_LoadStore()) {
1691         jobj->set_scalar_replaceable(false);
1692         return;
1693       }
1694     }
1695 
1696     // 6. Or the address may point to more then one object. This may produce
1697     // the false positive result (set not scalar replaceable)
1698     // since the flow-insensitive escape analysis can't separate
1699     // the case when stores overwrite the field's value from the case
1700     // when stores happened on different control branches.
1701     //
1702     // Note: it will disable scalar replacement in some cases:
1703     //
1704     //    Point p[] = new Point[1];
1705     //    p[0] = new Point(); // Will be not scalar replaced
1706     //
1707     // but it will save us from incorrect optimizations in next cases:
1708     //
1709     //    Point p[] = new Point[1];
1710     //    if ( x ) p[0] = new Point(); // Will be not scalar replaced
1711     //
1712     if (field->base_count() > 1) {
1713       for (BaseIterator i(field); i.has_next(); i.next()) {
1714         PointsToNode* base = i.get();
1715         // Don't take into account LocalVar nodes which
1716         // may point to only one object which should be also
1717         // this field's base by now.
1718         if (base->is_JavaObject() && base != jobj) {
1719           // Mark all bases.
1720           jobj->set_scalar_replaceable(false);
1721           base->set_scalar_replaceable(false);
1722         }
1723       }
1724     }
1725   }
1726 }
1727 
1728 #ifdef ASSERT
1729 void ConnectionGraph::verify_connection_graph(
1730                          GrowableArray<PointsToNode*>&   ptnodes_worklist,
1731                          GrowableArray<JavaObjectNode*>& non_escaped_worklist,
1732                          GrowableArray<JavaObjectNode*>& java_objects_worklist,
1733                          GrowableArray<Node*>& addp_worklist) {
1734   // Verify that graph is complete - no new edges could be added.
1735   int java_objects_length = java_objects_worklist.length();
1736   int non_escaped_length  = non_escaped_worklist.length();
1737   int new_edges = 0;
1738   for (int next = 0; next < java_objects_length; ++next) {
1739     JavaObjectNode* ptn = java_objects_worklist.at(next);
1740     new_edges += add_java_object_edges(ptn, true);
1741   }
1742   assert(new_edges == 0, "graph was not complete");
1743   // Verify that escape state is final.
1744   int length = non_escaped_worklist.length();
1745   find_non_escaped_objects(ptnodes_worklist, non_escaped_worklist);
1746   assert((non_escaped_length == non_escaped_worklist.length()) &&
1747          (non_escaped_length == length) &&
1748          (_worklist.length() == 0), "escape state was not final");
1749 
1750   // Verify fields information.
1751   int addp_length = addp_worklist.length();
1752   for (int next = 0; next < addp_length; ++next ) {
1753     Node* n = addp_worklist.at(next);
1754     FieldNode* field = ptnode_adr(n->_idx)->as_Field();
1755     if (field->is_oop()) {
1756       // Verify that field has all bases
1757       Node* base = get_addp_base(n);
1758       PointsToNode* ptn = ptnode_adr(base->_idx);
1759       if (ptn->is_JavaObject()) {
1760         assert(field->has_base(ptn->as_JavaObject()), "sanity");
1761       } else {
1762         assert(ptn->is_LocalVar(), "sanity");
1763         for (EdgeIterator i(ptn); i.has_next(); i.next()) {
1764           PointsToNode* e = i.get();
1765           if (e->is_JavaObject()) {
1766             assert(field->has_base(e->as_JavaObject()), "sanity");
1767           }
1768         }
1769       }
1770       // Verify that all fields have initializing values.
1771       if (field->edge_count() == 0) {
1772         tty->print_cr("----------field does not have references----------");
1773         field->dump();
1774         for (BaseIterator i(field); i.has_next(); i.next()) {
1775           PointsToNode* base = i.get();
1776           tty->print_cr("----------field has next base---------------------");
1777           base->dump();
1778           if (base->is_JavaObject() && (base != phantom_obj) && (base != null_obj)) {
1779             tty->print_cr("----------base has fields-------------------------");
1780             for (EdgeIterator j(base); j.has_next(); j.next()) {
1781               j.get()->dump();
1782             }
1783             tty->print_cr("----------base has references---------------------");
1784             for (UseIterator j(base); j.has_next(); j.next()) {
1785               j.get()->dump();
1786             }
1787           }
1788         }
1789         for (UseIterator i(field); i.has_next(); i.next()) {
1790           i.get()->dump();
1791         }
1792         assert(field->edge_count() > 0, "sanity");
1793       }
1794     }
1795   }
1796 }
1797 #endif
1798 
1799 // Optimize ideal graph.
1800 void ConnectionGraph::optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
1801                                            GrowableArray<Node*>& storestore_worklist) {
1802   Compile* C = _compile;
1803   PhaseIterGVN* igvn = _igvn;
1804   if (EliminateLocks) {
1805     // Mark locks before changing ideal graph.
1806     int cnt = C->macro_count();
1807     for( int i=0; i < cnt; i++ ) {
1808       Node *n = C->macro_node(i);
1809       if (n->is_AbstractLock()) { // Lock and Unlock nodes
1810         AbstractLockNode* alock = n->as_AbstractLock();
1811         if (!alock->is_non_esc_obj()) {
1812           if (not_global_escape(alock->obj_node())) {
1813             assert(!alock->is_eliminated() || alock->is_coarsened(), "sanity");
1814             // The lock could be marked eliminated by lock coarsening
1815             // code during first IGVN before EA. Replace coarsened flag
1816             // to eliminate all associated locks/unlocks.
1817 #ifdef ASSERT
1818             alock->log_lock_optimization(C, "eliminate_lock_set_non_esc3");
1819 #endif
1820             alock->set_non_esc_obj();
1821           }
1822         }
1823       }
1824     }
1825   }
1826 
1827   if (OptimizePtrCompare) {
1828     // Add ConI(#CC_GT) and ConI(#CC_EQ).
1829     _pcmp_neq = igvn->makecon(TypeInt::CC_GT);
1830     _pcmp_eq = igvn->makecon(TypeInt::CC_EQ);
1831     // Optimize objects compare.
1832     while (ptr_cmp_worklist.length() != 0) {
1833       Node *n = ptr_cmp_worklist.pop();
1834       Node *res = optimize_ptr_compare(n);
1835       if (res != NULL) {
1836 #ifndef PRODUCT
1837         if (PrintOptimizePtrCompare) {
1838           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"));
1839           if (Verbose) {
1840             n->dump(1);
1841           }
1842         }
1843 #endif
1844         igvn->replace_node(n, res);
1845       }
1846     }
1847     // cleanup
1848     if (_pcmp_neq->outcnt() == 0)
1849       igvn->hash_delete(_pcmp_neq);
1850     if (_pcmp_eq->outcnt()  == 0)
1851       igvn->hash_delete(_pcmp_eq);
1852   }
1853 
1854   // For MemBarStoreStore nodes added in library_call.cpp, check
1855   // escape status of associated AllocateNode and optimize out
1856   // MemBarStoreStore node if the allocated object never escapes.
1857   while (storestore_worklist.length() != 0) {
1858     Node *n = storestore_worklist.pop();
1859     MemBarStoreStoreNode *storestore = n ->as_MemBarStoreStore();
1860     Node *alloc = storestore->in(MemBarNode::Precedent)->in(0);
1861     assert (alloc->is_Allocate(), "storestore should point to AllocateNode");
1862     if (not_global_escape(alloc)) {
1863       MemBarNode* mb = MemBarNode::make(C, Op_MemBarCPUOrder, Compile::AliasIdxBot);
1864       mb->init_req(TypeFunc::Memory, storestore->in(TypeFunc::Memory));
1865       mb->init_req(TypeFunc::Control, storestore->in(TypeFunc::Control));
1866       igvn->register_new_node_with_optimizer(mb);
1867       igvn->replace_node(storestore, mb);
1868     }
1869   }
1870 }
1871 
1872 // Optimize objects compare.
1873 Node* ConnectionGraph::optimize_ptr_compare(Node* n) {
1874   assert(OptimizePtrCompare, "sanity");
1875   PointsToNode* ptn1 = ptnode_adr(n->in(1)->_idx);
1876   PointsToNode* ptn2 = ptnode_adr(n->in(2)->_idx);
1877   JavaObjectNode* jobj1 = unique_java_object(n->in(1));
1878   JavaObjectNode* jobj2 = unique_java_object(n->in(2));
1879   assert(ptn1->is_JavaObject() || ptn1->is_LocalVar(), "sanity");
1880   assert(ptn2->is_JavaObject() || ptn2->is_LocalVar(), "sanity");
1881 
1882   // Check simple cases first.
1883   if (jobj1 != NULL) {
1884     if (jobj1->escape_state() == PointsToNode::NoEscape) {
1885       if (jobj1 == jobj2) {
1886         // Comparing the same not escaping object.
1887         return _pcmp_eq;
1888       }
1889       Node* obj = jobj1->ideal_node();
1890       // Comparing not escaping allocation.
1891       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1892           !ptn2->points_to(jobj1)) {
1893         return _pcmp_neq; // This includes nullness check.
1894       }
1895     }
1896   }
1897   if (jobj2 != NULL) {
1898     if (jobj2->escape_state() == PointsToNode::NoEscape) {
1899       Node* obj = jobj2->ideal_node();
1900       // Comparing not escaping allocation.
1901       if ((obj->is_Allocate() || obj->is_CallStaticJava()) &&
1902           !ptn1->points_to(jobj2)) {
1903         return _pcmp_neq; // This includes nullness check.
1904       }
1905     }
1906   }
1907   if (jobj1 != NULL && jobj1 != phantom_obj &&
1908       jobj2 != NULL && jobj2 != phantom_obj &&
1909       jobj1->ideal_node()->is_Con() &&
1910       jobj2->ideal_node()->is_Con()) {
1911     // Klass or String constants compare. Need to be careful with
1912     // compressed pointers - compare types of ConN and ConP instead of nodes.
1913     const Type* t1 = jobj1->ideal_node()->get_ptr_type();
1914     const Type* t2 = jobj2->ideal_node()->get_ptr_type();
1915     if (t1->make_ptr() == t2->make_ptr()) {
1916       return _pcmp_eq;
1917     } else {
1918       return _pcmp_neq;
1919     }
1920   }
1921   if (ptn1->meet(ptn2)) {
1922     return NULL; // Sets are not disjoint
1923   }
1924 
1925   // Sets are disjoint.
1926   bool set1_has_unknown_ptr = ptn1->points_to(phantom_obj);
1927   bool set2_has_unknown_ptr = ptn2->points_to(phantom_obj);
1928   bool set1_has_null_ptr    = ptn1->points_to(null_obj);
1929   bool set2_has_null_ptr    = ptn2->points_to(null_obj);
1930   if (set1_has_unknown_ptr && set2_has_null_ptr ||
1931       set2_has_unknown_ptr && set1_has_null_ptr) {
1932     // Check nullness of unknown object.
1933     return NULL;
1934   }
1935 
1936   // Disjointness by itself is not sufficient since
1937   // alias analysis is not complete for escaped objects.
1938   // Disjoint sets are definitely unrelated only when
1939   // at least one set has only not escaping allocations.
1940   if (!set1_has_unknown_ptr && !set1_has_null_ptr) {
1941     if (ptn1->non_escaping_allocation()) {
1942       return _pcmp_neq;
1943     }
1944   }
1945   if (!set2_has_unknown_ptr && !set2_has_null_ptr) {
1946     if (ptn2->non_escaping_allocation()) {
1947       return _pcmp_neq;
1948     }
1949   }
1950   return NULL;
1951 }
1952 
1953 // Connection Graph constuction functions.
1954 
1955 void ConnectionGraph::add_local_var(Node *n, PointsToNode::EscapeState es) {
1956   PointsToNode* ptadr = _nodes.at(n->_idx);
1957   if (ptadr != NULL) {
1958     assert(ptadr->is_LocalVar() && ptadr->ideal_node() == n, "sanity");
1959     return;
1960   }
1961   Compile* C = _compile;
1962   ptadr = new (C->comp_arena()) LocalVarNode(this, n, es);
1963   _nodes.at_put(n->_idx, ptadr);
1964 }
1965 
1966 void ConnectionGraph::add_java_object(Node *n, PointsToNode::EscapeState es) {
1967   PointsToNode* ptadr = _nodes.at(n->_idx);
1968   if (ptadr != NULL) {
1969     assert(ptadr->is_JavaObject() && ptadr->ideal_node() == n, "sanity");
1970     return;
1971   }
1972   Compile* C = _compile;
1973   ptadr = new (C->comp_arena()) JavaObjectNode(this, n, es);
1974   _nodes.at_put(n->_idx, ptadr);
1975 }
1976 
1977 void ConnectionGraph::add_field(Node *n, PointsToNode::EscapeState es, int offset) {
1978   PointsToNode* ptadr = _nodes.at(n->_idx);
1979   if (ptadr != NULL) {
1980     assert(ptadr->is_Field() && ptadr->ideal_node() == n, "sanity");
1981     return;
1982   }
1983   bool unsafe = false;
1984   bool is_oop = is_oop_field(n, offset, &unsafe);
1985   if (unsafe) {
1986     es = PointsToNode::GlobalEscape;
1987   }
1988   Compile* C = _compile;
1989   FieldNode* field = new (C->comp_arena()) FieldNode(this, n, es, offset, is_oop);
1990   _nodes.at_put(n->_idx, field);
1991 }
1992 
1993 void ConnectionGraph::add_arraycopy(Node *n, PointsToNode::EscapeState es,
1994                                     PointsToNode* src, PointsToNode* dst) {
1995   assert(!src->is_Field() && !dst->is_Field(), "only for JavaObject and LocalVar");
1996   assert((src != null_obj) && (dst != null_obj), "not for ConP NULL");
1997   PointsToNode* ptadr = _nodes.at(n->_idx);
1998   if (ptadr != NULL) {
1999     assert(ptadr->is_Arraycopy() && ptadr->ideal_node() == n, "sanity");
2000     return;
2001   }
2002   Compile* C = _compile;
2003   ptadr = new (C->comp_arena()) ArraycopyNode(this, n, es);
2004   _nodes.at_put(n->_idx, ptadr);
2005   // Add edge from arraycopy node to source object.
2006   (void)add_edge(ptadr, src);
2007   src->set_arraycopy_src();
2008   // Add edge from destination object to arraycopy node.
2009   (void)add_edge(dst, ptadr);
2010   dst->set_arraycopy_dst();
2011 }
2012 
2013 bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
2014   const Type* adr_type = n->as_AddP()->bottom_type();
2015   BasicType bt = T_INT;
2016   if (offset == Type::OffsetBot) {
2017     // Check only oop fields.
2018     if (!adr_type->isa_aryptr() ||
2019         (adr_type->isa_aryptr()->klass() == NULL) ||
2020          adr_type->isa_aryptr()->klass()->is_obj_array_klass()) {
2021       // OffsetBot is used to reference array's element. Ignore first AddP.
2022       if (find_second_addp(n, n->in(AddPNode::Base)) == NULL) {
2023         bt = T_OBJECT;
2024       }
2025     }
2026   } else if (offset != oopDesc::klass_offset_in_bytes()) {
2027     if (adr_type->isa_instptr()) {
2028       ciField* field = _compile->alias_type(adr_type->isa_instptr())->field();
2029       if (field != NULL) {
2030         bt = field->layout_type();
2031       } else {
2032         // Check for unsafe oop field access
2033         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2034           int opcode = n->fast_out(i)->Opcode();
2035           if (opcode == Op_StoreP          || opcode == Op_StoreN ||
2036               opcode == Op_LoadP           || opcode == Op_LoadN  ||
2037               opcode == Op_GetAndSetP      || opcode == Op_GetAndSetN ||
2038               opcode == Op_CompareAndSwapP || opcode == Op_CompareAndSwapN) {
2039             bt = T_OBJECT;
2040             (*unsafe) = true;
2041             break;
2042           }
2043         }
2044       }
2045     } else if (adr_type->isa_aryptr()) {
2046       if (offset == arrayOopDesc::length_offset_in_bytes()) {
2047         // Ignore array length load.
2048       } else if (find_second_addp(n, n->in(AddPNode::Base)) != NULL) {
2049         // Ignore first AddP.
2050       } else {
2051         const Type* elemtype = adr_type->isa_aryptr()->elem();
2052         bt = elemtype->array_element_basic_type();
2053       }
2054     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
2055       // Allocation initialization, ThreadLocal field access, unsafe access
2056       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2057         int opcode = n->fast_out(i)->Opcode();
2058         if (opcode == Op_StoreP          || opcode == Op_StoreN ||
2059             opcode == Op_LoadP           || opcode == Op_LoadN  ||
2060             opcode == Op_GetAndSetP      || opcode == Op_GetAndSetN ||
2061             opcode == Op_CompareAndSwapP || opcode == Op_CompareAndSwapN) {
2062           bt = T_OBJECT;
2063           break;
2064         }
2065       }
2066     }
2067   }
2068   return (bt == T_OBJECT || bt == T_NARROWOOP || bt == T_ARRAY);
2069 }
2070 
2071 // Returns unique pointed java object or NULL.
2072 JavaObjectNode* ConnectionGraph::unique_java_object(Node *n) {
2073   assert(!_collecting, "should not call when contructed graph");
2074   // If the node was created after the escape computation we can't answer.
2075   uint idx = n->_idx;
2076   if (idx >= nodes_size()) {
2077     return NULL;
2078   }
2079   PointsToNode* ptn = ptnode_adr(idx);
2080   if (ptn == NULL) {
2081     return NULL;
2082   }
2083   if (ptn->is_JavaObject()) {
2084     return ptn->as_JavaObject();
2085   }
2086   assert(ptn->is_LocalVar(), "sanity");
2087   // Check all java objects it points to.
2088   JavaObjectNode* jobj = NULL;
2089   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2090     PointsToNode* e = i.get();
2091     if (e->is_JavaObject()) {
2092       if (jobj == NULL) {
2093         jobj = e->as_JavaObject();
2094       } else if (jobj != e) {
2095         return NULL;
2096       }
2097     }
2098   }
2099   return jobj;
2100 }
2101 
2102 // Return true if this node points only to non-escaping allocations.
2103 bool PointsToNode::non_escaping_allocation() {
2104   if (is_JavaObject()) {
2105     Node* n = ideal_node();
2106     if (n->is_Allocate() || n->is_CallStaticJava()) {
2107       return (escape_state() == PointsToNode::NoEscape);
2108     } else {
2109       return false;
2110     }
2111   }
2112   assert(is_LocalVar(), "sanity");
2113   // Check all java objects it points to.
2114   for (EdgeIterator i(this); i.has_next(); i.next()) {
2115     PointsToNode* e = i.get();
2116     if (e->is_JavaObject()) {
2117       Node* n = e->ideal_node();
2118       if ((e->escape_state() != PointsToNode::NoEscape) ||
2119           !(n->is_Allocate() || n->is_CallStaticJava())) {
2120         return false;
2121       }
2122     }
2123   }
2124   return true;
2125 }
2126 
2127 // Return true if we know the node does not escape globally.
2128 bool ConnectionGraph::not_global_escape(Node *n) {
2129   assert(!_collecting, "should not call during graph construction");
2130   // If the node was created after the escape computation we can't answer.
2131   uint idx = n->_idx;
2132   if (idx >= nodes_size()) {
2133     return false;
2134   }
2135   PointsToNode* ptn = ptnode_adr(idx);
2136   if (ptn == NULL) {
2137     return false; // not in congraph (e.g. ConI)
2138   }
2139   PointsToNode::EscapeState es = ptn->escape_state();
2140   // If we have already computed a value, return it.
2141   if (es >= PointsToNode::GlobalEscape)
2142     return false;
2143   if (ptn->is_JavaObject()) {
2144     return true; // (es < PointsToNode::GlobalEscape);
2145   }
2146   assert(ptn->is_LocalVar(), "sanity");
2147   // Check all java objects it points to.
2148   for (EdgeIterator i(ptn); i.has_next(); i.next()) {
2149     if (i.get()->escape_state() >= PointsToNode::GlobalEscape)
2150       return false;
2151   }
2152   return true;
2153 }
2154 
2155 
2156 // Helper functions
2157 
2158 // Return true if this node points to specified node or nodes it points to.
2159 bool PointsToNode::points_to(JavaObjectNode* ptn) const {
2160   if (is_JavaObject()) {
2161     return (this == ptn);
2162   }
2163   assert(is_LocalVar() || is_Field(), "sanity");
2164   for (EdgeIterator i(this); i.has_next(); i.next()) {
2165     if (i.get() == ptn)
2166       return true;
2167   }
2168   return false;
2169 }
2170 
2171 // Return true if one node points to an other.
2172 bool PointsToNode::meet(PointsToNode* ptn) {
2173   if (this == ptn) {
2174     return true;
2175   } else if (ptn->is_JavaObject()) {
2176     return this->points_to(ptn->as_JavaObject());
2177   } else if (this->is_JavaObject()) {
2178     return ptn->points_to(this->as_JavaObject());
2179   }
2180   assert(this->is_LocalVar() && ptn->is_LocalVar(), "sanity");
2181   int ptn_count =  ptn->edge_count();
2182   for (EdgeIterator i(this); i.has_next(); i.next()) {
2183     PointsToNode* this_e = i.get();
2184     for (int j = 0; j < ptn_count; j++) {
2185       if (this_e == ptn->edge(j))
2186         return true;
2187     }
2188   }
2189   return false;
2190 }
2191 
2192 #ifdef ASSERT
2193 // Return true if bases point to this java object.
2194 bool FieldNode::has_base(JavaObjectNode* jobj) const {
2195   for (BaseIterator i(this); i.has_next(); i.next()) {
2196     if (i.get() == jobj)
2197       return true;
2198   }
2199   return false;
2200 }
2201 #endif
2202 
2203 int ConnectionGraph::address_offset(Node* adr, PhaseTransform *phase) {
2204   const Type *adr_type = phase->type(adr);
2205   if (adr->is_AddP() && adr_type->isa_oopptr() == NULL &&
2206       adr->in(AddPNode::Address)->is_Proj() &&
2207       adr->in(AddPNode::Address)->in(0)->is_Allocate()) {
2208     // We are computing a raw address for a store captured by an Initialize
2209     // compute an appropriate address type. AddP cases #3 and #5 (see below).
2210     int offs = (int)phase->find_intptr_t_con(adr->in(AddPNode::Offset), Type::OffsetBot);
2211     assert(offs != Type::OffsetBot ||
2212            adr->in(AddPNode::Address)->in(0)->is_AllocateArray(),
2213            "offset must be a constant or it is initialization of array");
2214     return offs;
2215   }
2216   const TypePtr *t_ptr = adr_type->isa_ptr();
2217   assert(t_ptr != NULL, "must be a pointer type");
2218   return t_ptr->offset();
2219 }
2220 
2221 Node* ConnectionGraph::get_addp_base(Node *addp) {
2222   assert(addp->is_AddP(), "must be AddP");
2223   //
2224   // AddP cases for Base and Address inputs:
2225   // case #1. Direct object's field reference:
2226   //     Allocate
2227   //       |
2228   //     Proj #5 ( oop result )
2229   //       |
2230   //     CheckCastPP (cast to instance type)
2231   //      | |
2232   //     AddP  ( base == address )
2233   //
2234   // case #2. Indirect object's field reference:
2235   //      Phi
2236   //       |
2237   //     CastPP (cast to instance type)
2238   //      | |
2239   //     AddP  ( base == address )
2240   //
2241   // case #3. Raw object's field reference for Initialize node:
2242   //      Allocate
2243   //        |
2244   //      Proj #5 ( oop result )
2245   //  top   |
2246   //     \  |
2247   //     AddP  ( base == top )
2248   //
2249   // case #4. Array's element reference:
2250   //   {CheckCastPP | CastPP}
2251   //     |  | |
2252   //     |  AddP ( array's element offset )
2253   //     |  |
2254   //     AddP ( array's offset )
2255   //
2256   // case #5. Raw object's field reference for arraycopy stub call:
2257   //          The inline_native_clone() case when the arraycopy stub is called
2258   //          after the allocation before Initialize and CheckCastPP nodes.
2259   //      Allocate
2260   //        |
2261   //      Proj #5 ( oop result )
2262   //       | |
2263   //       AddP  ( base == address )
2264   //
2265   // case #6. Constant Pool, ThreadLocal, CastX2P or
2266   //          Raw object's field reference:
2267   //      {ConP, ThreadLocal, CastX2P, raw Load}
2268   //  top   |
2269   //     \  |
2270   //     AddP  ( base == top )
2271   //
2272   // case #7. Klass's field reference.
2273   //      LoadKlass
2274   //       | |
2275   //       AddP  ( base == address )
2276   //
2277   // case #8. narrow Klass's field reference.
2278   //      LoadNKlass
2279   //       |
2280   //      DecodeN
2281   //       | |
2282   //       AddP  ( base == address )
2283   //
2284   Node *base = addp->in(AddPNode::Base);
2285   if (base->uncast()->is_top()) { // The AddP case #3 and #6.
2286     base = addp->in(AddPNode::Address);
2287     while (base->is_AddP()) {
2288       // Case #6 (unsafe access) may have several chained AddP nodes.
2289       assert(base->in(AddPNode::Base)->uncast()->is_top(), "expected unsafe access address only");
2290       base = base->in(AddPNode::Address);
2291     }
2292     Node* uncast_base = base->uncast();
2293     int opcode = uncast_base->Opcode();
2294     assert(opcode == Op_ConP || opcode == Op_ThreadLocal ||
2295            opcode == Op_CastX2P || uncast_base->is_DecodeNarrowPtr() ||
2296            (uncast_base->is_Mem() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
2297            (uncast_base->is_Proj() && uncast_base->in(0)->is_Allocate()) ||
2298            (uncast_base->is_Phi() && (uncast_base->bottom_type()->isa_rawptr() != NULL)) ||
2299            uncast_base->Opcode() == Op_ShenandoahLoadReferenceBarrier, "sanity");
2300   }
2301   return base;
2302 }
2303 
2304 Node* ConnectionGraph::find_second_addp(Node* addp, Node* n) {
2305   assert(addp->is_AddP() && addp->outcnt() > 0, "Don't process dead nodes");
2306   Node* addp2 = addp->raw_out(0);
2307   if (addp->outcnt() == 1 && addp2->is_AddP() &&
2308       addp2->in(AddPNode::Base) == n &&
2309       addp2->in(AddPNode::Address) == addp) {
2310     assert(addp->in(AddPNode::Base) == n, "expecting the same base");
2311     //
2312     // Find array's offset to push it on worklist first and
2313     // as result process an array's element offset first (pushed second)
2314     // to avoid CastPP for the array's offset.
2315     // Otherwise the inserted CastPP (LocalVar) will point to what
2316     // the AddP (Field) points to. Which would be wrong since
2317     // the algorithm expects the CastPP has the same point as
2318     // as AddP's base CheckCastPP (LocalVar).
2319     //
2320     //    ArrayAllocation
2321     //     |
2322     //    CheckCastPP
2323     //     |
2324     //    memProj (from ArrayAllocation CheckCastPP)
2325     //     |  ||
2326     //     |  ||   Int (element index)
2327     //     |  ||    |   ConI (log(element size))
2328     //     |  ||    |   /
2329     //     |  ||   LShift
2330     //     |  ||  /
2331     //     |  AddP (array's element offset)
2332     //     |  |
2333     //     |  | ConI (array's offset: #12(32-bits) or #24(64-bits))
2334     //     | / /
2335     //     AddP (array's offset)
2336     //      |
2337     //     Load/Store (memory operation on array's element)
2338     //
2339     return addp2;
2340   }
2341   return NULL;
2342 }
2343 
2344 //
2345 // Adjust the type and inputs of an AddP which computes the
2346 // address of a field of an instance
2347 //
2348 bool ConnectionGraph::split_AddP(Node *addp, Node *base) {
2349   PhaseGVN* igvn = _igvn;
2350   const TypeOopPtr *base_t = igvn->type(base)->isa_oopptr();
2351   assert(base_t != NULL && base_t->is_known_instance(), "expecting instance oopptr");
2352   const TypeOopPtr *t = igvn->type(addp)->isa_oopptr();
2353   if (t == NULL) {
2354     // We are computing a raw address for a store captured by an Initialize
2355     // compute an appropriate address type (cases #3 and #5).
2356     assert(igvn->type(addp) == TypeRawPtr::NOTNULL, "must be raw pointer");
2357     assert(addp->in(AddPNode::Address)->is_Proj(), "base of raw address must be result projection from allocation");
2358     intptr_t offs = (int)igvn->find_intptr_t_con(addp->in(AddPNode::Offset), Type::OffsetBot);
2359     assert(offs != Type::OffsetBot, "offset must be a constant");
2360     t = base_t->add_offset(offs)->is_oopptr();
2361   }
2362   int inst_id =  base_t->instance_id();
2363   assert(!t->is_known_instance() || t->instance_id() == inst_id,
2364                              "old type must be non-instance or match new type");
2365 
2366   // The type 't' could be subclass of 'base_t'.
2367   // As result t->offset() could be large then base_t's size and it will
2368   // cause the failure in add_offset() with narrow oops since TypeOopPtr()
2369   // constructor verifies correctness of the offset.
2370   //
2371   // It could happened on subclass's branch (from the type profiling
2372   // inlining) which was not eliminated during parsing since the exactness
2373   // of the allocation type was not propagated to the subclass type check.
2374   //
2375   // Or the type 't' could be not related to 'base_t' at all.
2376   // It could happened when CHA type is different from MDO type on a dead path
2377   // (for example, from instanceof check) which is not collapsed during parsing.
2378   //
2379   // Do nothing for such AddP node and don't process its users since
2380   // this code branch will go away.
2381   //
2382   if (!t->is_known_instance() &&
2383       !base_t->klass()->is_subtype_of(t->klass())) {
2384      return false; // bail out
2385   }
2386   const TypeOopPtr *tinst = base_t->add_offset(t->offset())->is_oopptr();
2387   // Do NOT remove the next line: ensure a new alias index is allocated
2388   // for the instance type. Note: C++ will not remove it since the call
2389   // has side effect.
2390   int alias_idx = _compile->get_alias_index(tinst);
2391   igvn->set_type(addp, tinst);
2392   // record the allocation in the node map
2393   set_map(addp, get_map(base->_idx));
2394   // Set addp's Base and Address to 'base'.
2395   Node *abase = addp->in(AddPNode::Base);
2396   Node *adr   = addp->in(AddPNode::Address);
2397   if (adr->is_Proj() && adr->in(0)->is_Allocate() &&
2398       adr->in(0)->_idx == (uint)inst_id) {
2399     // Skip AddP cases #3 and #5.
2400   } else {
2401     assert(!abase->is_top(), "sanity"); // AddP case #3
2402     if (abase != base) {
2403       igvn->hash_delete(addp);
2404       addp->set_req(AddPNode::Base, base);
2405       if (abase == adr) {
2406         addp->set_req(AddPNode::Address, base);
2407       } else {
2408         // AddP case #4 (adr is array's element offset AddP node)
2409 #ifdef ASSERT
2410         const TypeOopPtr *atype = igvn->type(adr)->isa_oopptr();
2411         assert(adr->is_AddP() && atype != NULL &&
2412                atype->instance_id() == inst_id, "array's element offset should be processed first");
2413 #endif
2414       }
2415       igvn->hash_insert(addp);
2416     }
2417   }
2418   // Put on IGVN worklist since at least addp's type was changed above.
2419   record_for_optimizer(addp);
2420   return true;
2421 }
2422 
2423 //
2424 // Create a new version of orig_phi if necessary. Returns either the newly
2425 // created phi or an existing phi.  Sets create_new to indicate whether a new
2426 // phi was created.  Cache the last newly created phi in the node map.
2427 //
2428 PhiNode *ConnectionGraph::create_split_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist, bool &new_created) {
2429   Compile *C = _compile;
2430   PhaseGVN* igvn = _igvn;
2431   new_created = false;
2432   int phi_alias_idx = C->get_alias_index(orig_phi->adr_type());
2433   // nothing to do if orig_phi is bottom memory or matches alias_idx
2434   if (phi_alias_idx == alias_idx) {
2435     return orig_phi;
2436   }
2437   // Have we recently created a Phi for this alias index?
2438   PhiNode *result = get_map_phi(orig_phi->_idx);
2439   if (result != NULL && C->get_alias_index(result->adr_type()) == alias_idx) {
2440     return result;
2441   }
2442   // Previous check may fail when the same wide memory Phi was split into Phis
2443   // for different memory slices. Search all Phis for this region.
2444   if (result != NULL) {
2445     Node* region = orig_phi->in(0);
2446     for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
2447       Node* phi = region->fast_out(i);
2448       if (phi->is_Phi() &&
2449           C->get_alias_index(phi->as_Phi()->adr_type()) == alias_idx) {
2450         assert(phi->_idx >= nodes_size(), "only new Phi per instance memory slice");
2451         return phi->as_Phi();
2452       }
2453     }
2454   }
2455   if (C->live_nodes() + 2*NodeLimitFudgeFactor > C->max_node_limit()) {
2456     if (C->do_escape_analysis() == true && !C->failing()) {
2457       // Retry compilation without escape analysis.
2458       // If this is the first failure, the sentinel string will "stick"
2459       // to the Compile object, and the C2Compiler will see it and retry.
2460       C->record_failure(C2Compiler::retry_no_escape_analysis());
2461     }
2462     return NULL;
2463   }
2464   orig_phi_worklist.append_if_missing(orig_phi);
2465   const TypePtr *atype = C->get_adr_type(alias_idx);
2466   result = PhiNode::make(orig_phi->in(0), NULL, Type::MEMORY, atype);
2467   C->copy_node_notes_to(result, orig_phi);
2468   igvn->set_type(result, result->bottom_type());
2469   record_for_optimizer(result);
2470   set_map(orig_phi, result);
2471   new_created = true;
2472   return result;
2473 }
2474 
2475 //
2476 // Return a new version of Memory Phi "orig_phi" with the inputs having the
2477 // specified alias index.
2478 //
2479 PhiNode *ConnectionGraph::split_memory_phi(PhiNode *orig_phi, int alias_idx, GrowableArray<PhiNode *>  &orig_phi_worklist) {
2480   assert(alias_idx != Compile::AliasIdxBot, "can't split out bottom memory");
2481   Compile *C = _compile;
2482   PhaseGVN* igvn = _igvn;
2483   bool new_phi_created;
2484   PhiNode *result = create_split_phi(orig_phi, alias_idx, orig_phi_worklist, new_phi_created);
2485   if (!new_phi_created) {
2486     return result;
2487   }
2488   GrowableArray<PhiNode *>  phi_list;
2489   GrowableArray<uint>  cur_input;
2490   PhiNode *phi = orig_phi;
2491   uint idx = 1;
2492   bool finished = false;
2493   while(!finished) {
2494     while (idx < phi->req()) {
2495       Node *mem = find_inst_mem(phi->in(idx), alias_idx, orig_phi_worklist);
2496       if (mem != NULL && mem->is_Phi()) {
2497         PhiNode *newphi = create_split_phi(mem->as_Phi(), alias_idx, orig_phi_worklist, new_phi_created);
2498         if (new_phi_created) {
2499           // found an phi for which we created a new split, push current one on worklist and begin
2500           // processing new one
2501           phi_list.push(phi);
2502           cur_input.push(idx);
2503           phi = mem->as_Phi();
2504           result = newphi;
2505           idx = 1;
2506           continue;
2507         } else {
2508           mem = newphi;
2509         }
2510       }
2511       if (C->failing()) {
2512         return NULL;
2513       }
2514       result->set_req(idx++, mem);
2515     }
2516 #ifdef ASSERT
2517     // verify that the new Phi has an input for each input of the original
2518     assert( phi->req() == result->req(), "must have same number of inputs.");
2519     assert( result->in(0) != NULL && result->in(0) == phi->in(0), "regions must match");
2520 #endif
2521     // Check if all new phi's inputs have specified alias index.
2522     // Otherwise use old phi.
2523     for (uint i = 1; i < phi->req(); i++) {
2524       Node* in = result->in(i);
2525       assert((phi->in(i) == NULL) == (in == NULL), "inputs must correspond.");
2526     }
2527     // we have finished processing a Phi, see if there are any more to do
2528     finished = (phi_list.length() == 0 );
2529     if (!finished) {
2530       phi = phi_list.pop();
2531       idx = cur_input.pop();
2532       PhiNode *prev_result = get_map_phi(phi->_idx);
2533       prev_result->set_req(idx++, result);
2534       result = prev_result;
2535     }
2536   }
2537   return result;
2538 }
2539 
2540 //
2541 // The next methods are derived from methods in MemNode.
2542 //
2543 Node* ConnectionGraph::step_through_mergemem(MergeMemNode *mmem, int alias_idx, const TypeOopPtr *toop) {
2544   Node *mem = mmem;
2545   // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
2546   // means an array I have not precisely typed yet.  Do not do any
2547   // alias stuff with it any time soon.
2548   if (toop->base() != Type::AnyPtr &&
2549       !(toop->klass() != NULL &&
2550         toop->klass()->is_java_lang_Object() &&
2551         toop->offset() == Type::OffsetBot)) {
2552     mem = mmem->memory_at(alias_idx);
2553     // Update input if it is progress over what we have now
2554   }
2555   return mem;
2556 }
2557 
2558 //
2559 // Move memory users to their memory slices.
2560 //
2561 void ConnectionGraph::move_inst_mem(Node* n, GrowableArray<PhiNode *>  &orig_phis) {
2562   Compile* C = _compile;
2563   PhaseGVN* igvn = _igvn;
2564   const TypePtr* tp = igvn->type(n->in(MemNode::Address))->isa_ptr();
2565   assert(tp != NULL, "ptr type");
2566   int alias_idx = C->get_alias_index(tp);
2567   int general_idx = C->get_general_index(alias_idx);
2568 
2569   // Move users first
2570   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2571     Node* use = n->fast_out(i);
2572     if (use->is_MergeMem()) {
2573       MergeMemNode* mmem = use->as_MergeMem();
2574       assert(n == mmem->memory_at(alias_idx), "should be on instance memory slice");
2575       if (n != mmem->memory_at(general_idx) || alias_idx == general_idx) {
2576         continue; // Nothing to do
2577       }
2578       // Replace previous general reference to mem node.
2579       uint orig_uniq = C->unique();
2580       Node* m = find_inst_mem(n, general_idx, orig_phis);
2581       assert(orig_uniq == C->unique(), "no new nodes");
2582       mmem->set_memory_at(general_idx, m);
2583       --imax;
2584       --i;
2585     } else if (use->is_MemBar()) {
2586       assert(!use->is_Initialize(), "initializing stores should not be moved");
2587       if (use->req() > MemBarNode::Precedent &&
2588           use->in(MemBarNode::Precedent) == n) {
2589         // Don't move related membars.
2590         record_for_optimizer(use);
2591         continue;
2592       }
2593       tp = use->as_MemBar()->adr_type()->isa_ptr();
2594       if (tp != NULL && C->get_alias_index(tp) == alias_idx ||
2595           alias_idx == general_idx) {
2596         continue; // Nothing to do
2597       }
2598       // Move to general memory slice.
2599       uint orig_uniq = C->unique();
2600       Node* m = find_inst_mem(n, general_idx, orig_phis);
2601       assert(orig_uniq == C->unique(), "no new nodes");
2602       igvn->hash_delete(use);
2603       imax -= use->replace_edge(n, m);
2604       igvn->hash_insert(use);
2605       record_for_optimizer(use);
2606       --i;
2607 #ifdef ASSERT
2608     } else if (use->is_Mem()) {
2609       if (use->Opcode() == Op_StoreCM && use->in(MemNode::OopStore) == n) {
2610         // Don't move related cardmark.
2611         continue;
2612       }
2613       // Memory nodes should have new memory input.
2614       tp = igvn->type(use->in(MemNode::Address))->isa_ptr();
2615       assert(tp != NULL, "ptr type");
2616       int idx = C->get_alias_index(tp);
2617       assert(get_map(use->_idx) != NULL || idx == alias_idx,
2618              "Following memory nodes should have new memory input or be on the same memory slice");
2619     } else if (use->is_Phi()) {
2620       // Phi nodes should be split and moved already.
2621       tp = use->as_Phi()->adr_type()->isa_ptr();
2622       assert(tp != NULL, "ptr type");
2623       int idx = C->get_alias_index(tp);
2624       assert(idx == alias_idx, "Following Phi nodes should be on the same memory slice");
2625     } else {
2626       use->dump();
2627       assert(false, "should not be here");
2628 #endif
2629     }
2630   }
2631 }
2632 
2633 //
2634 // Search memory chain of "mem" to find a MemNode whose address
2635 // is the specified alias index.
2636 //
2637 Node* ConnectionGraph::find_inst_mem(Node *orig_mem, int alias_idx, GrowableArray<PhiNode *>  &orig_phis) {
2638   if (orig_mem == NULL)
2639     return orig_mem;
2640   Compile* C = _compile;
2641   PhaseGVN* igvn = _igvn;
2642   const TypeOopPtr *toop = C->get_adr_type(alias_idx)->isa_oopptr();
2643   bool is_instance = (toop != NULL) && toop->is_known_instance();
2644   Node *start_mem = C->start()->proj_out(TypeFunc::Memory);
2645   Node *prev = NULL;
2646   Node *result = orig_mem;
2647   while (prev != result) {
2648     prev = result;
2649     if (result == start_mem)
2650       break;  // hit one of our sentinels
2651     if (result->is_Mem()) {
2652       const Type *at = igvn->type(result->in(MemNode::Address));
2653       if (at == Type::TOP)
2654         break; // Dead
2655       assert (at->isa_ptr() != NULL, "pointer type required.");
2656       int idx = C->get_alias_index(at->is_ptr());
2657       if (idx == alias_idx)
2658         break; // Found
2659       if (!is_instance && (at->isa_oopptr() == NULL ||
2660                            !at->is_oopptr()->is_known_instance())) {
2661         break; // Do not skip store to general memory slice.
2662       }
2663       result = result->in(MemNode::Memory);
2664     }
2665     if (!is_instance)
2666       continue;  // don't search further for non-instance types
2667     // skip over a call which does not affect this memory slice
2668     if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
2669       Node *proj_in = result->in(0);
2670       if (proj_in->is_Allocate() && proj_in->_idx == (uint)toop->instance_id()) {
2671         break;  // hit one of our sentinels
2672       } else if (proj_in->is_Call()) {
2673         CallNode *call = proj_in->as_Call();
2674         if (!call->may_modify(toop, igvn)) {
2675           result = call->in(TypeFunc::Memory);
2676         }
2677       } else if (proj_in->is_Initialize()) {
2678         AllocateNode* alloc = proj_in->as_Initialize()->allocation();
2679         // Stop if this is the initialization for the object instance which
2680         // which contains this memory slice, otherwise skip over it.
2681         if (alloc == NULL || alloc->_idx != (uint)toop->instance_id()) {
2682           result = proj_in->in(TypeFunc::Memory);
2683         }
2684       } else if (proj_in->is_MemBar()) {
2685         result = proj_in->in(TypeFunc::Memory);
2686       }
2687     } else if (result->is_MergeMem()) {
2688       MergeMemNode *mmem = result->as_MergeMem();
2689       result = step_through_mergemem(mmem, alias_idx, toop);
2690       if (result == mmem->base_memory()) {
2691         // Didn't find instance memory, search through general slice recursively.
2692         result = mmem->memory_at(C->get_general_index(alias_idx));
2693         result = find_inst_mem(result, alias_idx, orig_phis);
2694         if (C->failing()) {
2695           return NULL;
2696         }
2697         mmem->set_memory_at(alias_idx, result);
2698       }
2699     } else if (result->is_Phi() &&
2700                C->get_alias_index(result->as_Phi()->adr_type()) != alias_idx) {
2701       Node *un = result->as_Phi()->unique_input(igvn);
2702       if (un != NULL) {
2703         orig_phis.append_if_missing(result->as_Phi());
2704         result = un;
2705       } else {
2706         break;
2707       }
2708     } else if (result->is_ClearArray()) {
2709       if (!ClearArrayNode::step_through(&result, (uint)toop->instance_id(), igvn)) {
2710         // Can not bypass initialization of the instance
2711         // we are looking for.
2712         break;
2713       }
2714       // Otherwise skip it (the call updated 'result' value).
2715     } else if (result->Opcode() == Op_SCMemProj) {
2716       Node* mem = result->in(0);
2717       Node* adr = NULL;
2718       if (mem->is_LoadStore()) {
2719         adr = mem->in(MemNode::Address);
2720       } else {
2721         assert(mem->Opcode() == Op_EncodeISOArray, "sanity");
2722         adr = mem->in(3); // Memory edge corresponds to destination array
2723       }
2724       const Type *at = igvn->type(adr);
2725       if (at != Type::TOP) {
2726         assert (at->isa_ptr() != NULL, "pointer type required.");
2727         int idx = C->get_alias_index(at->is_ptr());
2728         assert(idx != alias_idx, "Object is not scalar replaceable if a LoadStore node access its field");
2729         break;
2730       }
2731       result = mem->in(MemNode::Memory);
2732     }
2733   }
2734   if (result->is_Phi()) {
2735     PhiNode *mphi = result->as_Phi();
2736     assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
2737     const TypePtr *t = mphi->adr_type();
2738     if (!is_instance) {
2739       // Push all non-instance Phis on the orig_phis worklist to update inputs
2740       // during Phase 4 if needed.
2741       orig_phis.append_if_missing(mphi);
2742     } else if (C->get_alias_index(t) != alias_idx) {
2743       // Create a new Phi with the specified alias index type.
2744       result = split_memory_phi(mphi, alias_idx, orig_phis);
2745     }
2746   }
2747   // the result is either MemNode, PhiNode, InitializeNode.
2748   return result;
2749 }
2750 
2751 //
2752 //  Convert the types of unescaped object to instance types where possible,
2753 //  propagate the new type information through the graph, and update memory
2754 //  edges and MergeMem inputs to reflect the new type.
2755 //
2756 //  We start with allocations (and calls which may be allocations)  on alloc_worklist.
2757 //  The processing is done in 4 phases:
2758 //
2759 //  Phase 1:  Process possible allocations from alloc_worklist.  Create instance
2760 //            types for the CheckCastPP for allocations where possible.
2761 //            Propagate the the new types through users as follows:
2762 //               casts and Phi:  push users on alloc_worklist
2763 //               AddP:  cast Base and Address inputs to the instance type
2764 //                      push any AddP users on alloc_worklist and push any memnode
2765 //                      users onto memnode_worklist.
2766 //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
2767 //            search the Memory chain for a store with the appropriate type
2768 //            address type.  If a Phi is found, create a new version with
2769 //            the appropriate memory slices from each of the Phi inputs.
2770 //            For stores, process the users as follows:
2771 //               MemNode:  push on memnode_worklist
2772 //               MergeMem: push on mergemem_worklist
2773 //  Phase 3:  Process MergeMem nodes from mergemem_worklist.  Walk each memory slice
2774 //            moving the first node encountered of each  instance type to the
2775 //            the input corresponding to its alias index.
2776 //            appropriate memory slice.
2777 //  Phase 4:  Update the inputs of non-instance memory Phis and the Memory input of memnodes.
2778 //
2779 // In the following example, the CheckCastPP nodes are the cast of allocation
2780 // results and the allocation of node 29 is unescaped and eligible to be an
2781 // instance type.
2782 //
2783 // We start with:
2784 //
2785 //     7 Parm #memory
2786 //    10  ConI  "12"
2787 //    19  CheckCastPP   "Foo"
2788 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2789 //    29  CheckCastPP   "Foo"
2790 //    30  AddP  _ 29 29 10  Foo+12  alias_index=4
2791 //
2792 //    40  StoreP  25   7  20   ... alias_index=4
2793 //    50  StoreP  35  40  30   ... alias_index=4
2794 //    60  StoreP  45  50  20   ... alias_index=4
2795 //    70  LoadP    _  60  30   ... alias_index=4
2796 //    80  Phi     75  50  60   Memory alias_index=4
2797 //    90  LoadP    _  80  30   ... alias_index=4
2798 //   100  LoadP    _  80  20   ... alias_index=4
2799 //
2800 //
2801 // Phase 1 creates an instance type for node 29 assigning it an instance id of 24
2802 // and creating a new alias index for node 30.  This gives:
2803 //
2804 //     7 Parm #memory
2805 //    10  ConI  "12"
2806 //    19  CheckCastPP   "Foo"
2807 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2808 //    29  CheckCastPP   "Foo"  iid=24
2809 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2810 //
2811 //    40  StoreP  25   7  20   ... alias_index=4
2812 //    50  StoreP  35  40  30   ... alias_index=6
2813 //    60  StoreP  45  50  20   ... alias_index=4
2814 //    70  LoadP    _  60  30   ... alias_index=6
2815 //    80  Phi     75  50  60   Memory alias_index=4
2816 //    90  LoadP    _  80  30   ... alias_index=6
2817 //   100  LoadP    _  80  20   ... alias_index=4
2818 //
2819 // In phase 2, new memory inputs are computed for the loads and stores,
2820 // And a new version of the phi is created.  In phase 4, the inputs to
2821 // node 80 are updated and then the memory nodes are updated with the
2822 // values computed in phase 2.  This results in:
2823 //
2824 //     7 Parm #memory
2825 //    10  ConI  "12"
2826 //    19  CheckCastPP   "Foo"
2827 //    20  AddP  _ 19 19 10  Foo+12  alias_index=4
2828 //    29  CheckCastPP   "Foo"  iid=24
2829 //    30  AddP  _ 29 29 10  Foo+12  alias_index=6  iid=24
2830 //
2831 //    40  StoreP  25  7   20   ... alias_index=4
2832 //    50  StoreP  35  7   30   ... alias_index=6
2833 //    60  StoreP  45  40  20   ... alias_index=4
2834 //    70  LoadP    _  50  30   ... alias_index=6
2835 //    80  Phi     75  40  60   Memory alias_index=4
2836 //   120  Phi     75  50  50   Memory alias_index=6
2837 //    90  LoadP    _ 120  30   ... alias_index=6
2838 //   100  LoadP    _  80  20   ... alias_index=4
2839 //
2840 void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist) {
2841   GrowableArray<Node *>  memnode_worklist;
2842   GrowableArray<PhiNode *>  orig_phis;
2843   PhaseIterGVN  *igvn = _igvn;
2844   uint new_index_start = (uint) _compile->num_alias_types();
2845   Arena* arena = Thread::current()->resource_area();
2846   VectorSet visited(arena);
2847   ideal_nodes.clear(); // Reset for use with set_map/get_map.
2848   uint unique_old = _compile->unique();
2849 
2850   //  Phase 1:  Process possible allocations from alloc_worklist.
2851   //  Create instance types for the CheckCastPP for allocations where possible.
2852   //
2853   // (Note: don't forget to change the order of the second AddP node on
2854   //  the alloc_worklist if the order of the worklist processing is changed,
2855   //  see the comment in find_second_addp().)
2856   //
2857   while (alloc_worklist.length() != 0) {
2858     Node *n = alloc_worklist.pop();
2859     uint ni = n->_idx;
2860     if (n->is_Call()) {
2861       CallNode *alloc = n->as_Call();
2862       // copy escape information to call node
2863       PointsToNode* ptn = ptnode_adr(alloc->_idx);
2864       PointsToNode::EscapeState es = ptn->escape_state();
2865       // We have an allocation or call which returns a Java object,
2866       // see if it is unescaped.
2867       if (es != PointsToNode::NoEscape || !ptn->scalar_replaceable())
2868         continue;
2869       // Find CheckCastPP for the allocate or for the return value of a call
2870       n = alloc->result_cast();
2871       if (n == NULL) {            // No uses except Initialize node
2872         if (alloc->is_Allocate()) {
2873           // Set the scalar_replaceable flag for allocation
2874           // so it could be eliminated if it has no uses.
2875           alloc->as_Allocate()->_is_scalar_replaceable = true;
2876         }
2877         if (alloc->is_CallStaticJava()) {
2878           // Set the scalar_replaceable flag for boxing method
2879           // so it could be eliminated if it has no uses.
2880           alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2881         }
2882         continue;
2883       }
2884       if (!n->is_CheckCastPP()) { // not unique CheckCastPP.
2885         assert(!alloc->is_Allocate(), "allocation should have unique type");
2886         continue;
2887       }
2888 
2889       // The inline code for Object.clone() casts the allocation result to
2890       // java.lang.Object and then to the actual type of the allocated
2891       // object. Detect this case and use the second cast.
2892       // Also detect j.l.reflect.Array.newInstance(jobject, jint) case when
2893       // the allocation result is cast to java.lang.Object and then
2894       // to the actual Array type.
2895       if (alloc->is_Allocate() && n->as_Type()->type() == TypeInstPtr::NOTNULL
2896           && (alloc->is_AllocateArray() ||
2897               igvn->type(alloc->in(AllocateNode::KlassNode)) != TypeKlassPtr::OBJECT)) {
2898         Node *cast2 = NULL;
2899         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2900           Node *use = n->fast_out(i);
2901           if (use->is_CheckCastPP()) {
2902             cast2 = use;
2903             break;
2904           }
2905         }
2906         if (cast2 != NULL) {
2907           n = cast2;
2908         } else {
2909           // Non-scalar replaceable if the allocation type is unknown statically
2910           // (reflection allocation), the object can't be restored during
2911           // deoptimization without precise type.
2912           continue;
2913         }
2914       }
2915 
2916       const TypeOopPtr *t = igvn->type(n)->isa_oopptr();
2917       if (t == NULL)
2918         continue;  // not a TypeOopPtr
2919       if (!t->klass_is_exact())
2920         continue; // not an unique type
2921 
2922       if (alloc->is_Allocate()) {
2923         // Set the scalar_replaceable flag for allocation
2924         // so it could be eliminated.
2925         alloc->as_Allocate()->_is_scalar_replaceable = true;
2926       }
2927       if (alloc->is_CallStaticJava()) {
2928         // Set the scalar_replaceable flag for boxing method
2929         // so it could be eliminated.
2930         alloc->as_CallStaticJava()->_is_scalar_replaceable = true;
2931       }
2932       set_escape_state(ptnode_adr(n->_idx), es); // CheckCastPP escape state
2933       // in order for an object to be scalar-replaceable, it must be:
2934       //   - a direct allocation (not a call returning an object)
2935       //   - non-escaping
2936       //   - eligible to be a unique type
2937       //   - not determined to be ineligible by escape analysis
2938       set_map(alloc, n);
2939       set_map(n, alloc);
2940       const TypeOopPtr* tinst = t->cast_to_instance_id(ni);
2941       igvn->hash_delete(n);
2942       igvn->set_type(n,  tinst);
2943       n->raise_bottom_type(tinst);
2944       igvn->hash_insert(n);
2945       record_for_optimizer(n);
2946       if (alloc->is_Allocate() && (t->isa_instptr() || t->isa_aryptr())) {
2947 
2948         // First, put on the worklist all Field edges from Connection Graph
2949         // which is more accurate then putting immediate users from Ideal Graph.
2950         for (EdgeIterator e(ptn); e.has_next(); e.next()) {
2951           PointsToNode* tgt = e.get();
2952           Node* use = tgt->ideal_node();
2953           assert(tgt->is_Field() && use->is_AddP(),
2954                  "only AddP nodes are Field edges in CG");
2955           if (use->outcnt() > 0) { // Don't process dead nodes
2956             Node* addp2 = find_second_addp(use, use->in(AddPNode::Base));
2957             if (addp2 != NULL) {
2958               assert(alloc->is_AllocateArray(),"array allocation was expected");
2959               alloc_worklist.append_if_missing(addp2);
2960             }
2961             alloc_worklist.append_if_missing(use);
2962           }
2963         }
2964 
2965         // An allocation may have an Initialize which has raw stores. Scan
2966         // the users of the raw allocation result and push AddP users
2967         // on alloc_worklist.
2968         Node *raw_result = alloc->proj_out(TypeFunc::Parms);
2969         assert (raw_result != NULL, "must have an allocation result");
2970         for (DUIterator_Fast imax, i = raw_result->fast_outs(imax); i < imax; i++) {
2971           Node *use = raw_result->fast_out(i);
2972           if (use->is_AddP() && use->outcnt() > 0) { // Don't process dead nodes
2973             Node* addp2 = find_second_addp(use, raw_result);
2974             if (addp2 != NULL) {
2975               assert(alloc->is_AllocateArray(),"array allocation was expected");
2976               alloc_worklist.append_if_missing(addp2);
2977             }
2978             alloc_worklist.append_if_missing(use);
2979           } else if (use->is_MemBar()) {
2980             memnode_worklist.append_if_missing(use);
2981           }
2982         }
2983       }
2984     } else if (n->is_AddP()) {
2985       JavaObjectNode* jobj = unique_java_object(get_addp_base(n));
2986       if (jobj == NULL || jobj == phantom_obj) {
2987 #ifdef ASSERT
2988         ptnode_adr(get_addp_base(n)->_idx)->dump();
2989         ptnode_adr(n->_idx)->dump();
2990         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
2991 #endif
2992         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
2993         return;
2994       }
2995       Node *base = get_map(jobj->idx());  // CheckCastPP node
2996       if (!split_AddP(n, base)) continue; // wrong type from dead path
2997     } else if (n->is_Phi() ||
2998                n->is_CheckCastPP() ||
2999                n->is_EncodeP() ||
3000                n->is_DecodeN() ||
3001                (n->is_ConstraintCast() && n->Opcode() == Op_CastPP)) {
3002       if (visited.test_set(n->_idx)) {
3003         assert(n->is_Phi(), "loops only through Phi's");
3004         continue;  // already processed
3005       }
3006       JavaObjectNode* jobj = unique_java_object(n);
3007       if (jobj == NULL || jobj == phantom_obj) {
3008 #ifdef ASSERT
3009         ptnode_adr(n->_idx)->dump();
3010         assert(jobj != NULL && jobj != phantom_obj, "escaped allocation");
3011 #endif
3012         _compile->record_failure(C2Compiler::retry_no_escape_analysis());
3013         return;
3014       } else {
3015         Node *val = get_map(jobj->idx());   // CheckCastPP node
3016         TypeNode *tn = n->as_Type();
3017         const TypeOopPtr* tinst = igvn->type(val)->isa_oopptr();
3018         assert(tinst != NULL && tinst->is_known_instance() &&
3019                tinst->instance_id() == jobj->idx() , "instance type expected.");
3020 
3021         const Type *tn_type = igvn->type(tn);
3022         const TypeOopPtr *tn_t;
3023         if (tn_type->isa_narrowoop()) {
3024           tn_t = tn_type->make_ptr()->isa_oopptr();
3025         } else {
3026           tn_t = tn_type->isa_oopptr();
3027         }
3028         if (tn_t != NULL && tinst->klass()->is_subtype_of(tn_t->klass())) {
3029           if (tn_type->isa_narrowoop()) {
3030             tn_type = tinst->make_narrowoop();
3031           } else {
3032             tn_type = tinst;
3033           }
3034           igvn->hash_delete(tn);
3035           igvn->set_type(tn, tn_type);
3036           tn->set_type(tn_type);
3037           igvn->hash_insert(tn);
3038           record_for_optimizer(n);
3039         } else {
3040           assert(tn_type == TypePtr::NULL_PTR ||
3041                  tn_t != NULL && !tinst->klass()->is_subtype_of(tn_t->klass()),
3042                  "unexpected type");
3043           continue; // Skip dead path with different type
3044         }
3045       }
3046     } else {
3047       debug_only(n->dump();)
3048       assert(false, "EA: unexpected node");
3049       continue;
3050     }
3051     // push allocation's users on appropriate worklist
3052     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3053       Node *use = n->fast_out(i);
3054       if(use->is_Mem() && use->in(MemNode::Address) == n) {
3055         // Load/store to instance's field
3056         memnode_worklist.append_if_missing(use);
3057       } else if (use->is_MemBar()) {
3058         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3059           memnode_worklist.append_if_missing(use);
3060         }
3061       } else if (use->is_AddP() && use->outcnt() > 0) { // No dead nodes
3062         Node* addp2 = find_second_addp(use, n);
3063         if (addp2 != NULL) {
3064           alloc_worklist.append_if_missing(addp2);
3065         }
3066         alloc_worklist.append_if_missing(use);
3067       } else if (use->is_Phi() ||
3068                  use->is_CheckCastPP() ||
3069                  use->is_EncodeNarrowPtr() ||
3070                  use->is_DecodeNarrowPtr() ||
3071                  (use->is_ConstraintCast() && use->Opcode() == Op_CastPP)) {
3072         alloc_worklist.append_if_missing(use);
3073 #ifdef ASSERT
3074       } else if (use->is_Mem()) {
3075         assert(use->in(MemNode::Address) != n, "EA: missing allocation reference path");
3076       } else if (use->is_MergeMem()) {
3077         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3078       } else if (use->is_SafePoint()) {
3079         // Look for MergeMem nodes for calls which reference unique allocation
3080         // (through CheckCastPP nodes) even for debug info.
3081         Node* m = use->in(TypeFunc::Memory);
3082         if (m->is_MergeMem()) {
3083           assert(_mergemem_worklist.contains(m->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3084         }
3085       } else if (use->Opcode() == Op_EncodeISOArray) {
3086         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3087           // EncodeISOArray overwrites destination array
3088           memnode_worklist.append_if_missing(use);
3089         }
3090       } else {
3091         uint op = use->Opcode();
3092         if (!(op == Op_CmpP || op == Op_Conv2B ||
3093               op == Op_CastP2X || op == Op_StoreCM ||
3094               op == Op_FastLock || op == Op_AryEq || op == Op_StrComp ||
3095               op == Op_StrEquals || op == Op_StrIndexOf)) {
3096           n->dump();
3097           use->dump();
3098           assert(false, "EA: missing allocation reference path");
3099         }
3100 #endif
3101       }
3102     }
3103 
3104   }
3105   // New alias types were created in split_AddP().
3106   uint new_index_end = (uint) _compile->num_alias_types();
3107   assert(unique_old == _compile->unique(), "there should be no new ideal nodes after Phase 1");
3108 
3109   //  Phase 2:  Process MemNode's from memnode_worklist. compute new address type and
3110   //            compute new values for Memory inputs  (the Memory inputs are not
3111   //            actually updated until phase 4.)
3112   if (memnode_worklist.length() == 0)
3113     return;  // nothing to do
3114   while (memnode_worklist.length() != 0) {
3115     Node *n = memnode_worklist.pop();
3116     if (visited.test_set(n->_idx))
3117       continue;
3118     if (n->is_Phi() || n->is_ClearArray()) {
3119       // we don't need to do anything, but the users must be pushed
3120     } else if (n->is_MemBar()) { // Initialize, MemBar nodes
3121       // we don't need to do anything, but the users must be pushed
3122       n = n->as_MemBar()->proj_out(TypeFunc::Memory);
3123       if (n == NULL)
3124         continue;
3125     } else if (n->Opcode() == Op_EncodeISOArray) {
3126       // get the memory projection
3127       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3128         Node *use = n->fast_out(i);
3129         if (use->Opcode() == Op_SCMemProj) {
3130           n = use;
3131           break;
3132         }
3133       }
3134       assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3135     } else {
3136       assert(n->is_Mem(), "memory node required.");
3137       Node *addr = n->in(MemNode::Address);
3138       const Type *addr_t = igvn->type(addr);
3139       if (addr_t == Type::TOP)
3140         continue;
3141       assert (addr_t->isa_ptr() != NULL, "pointer type required.");
3142       int alias_idx = _compile->get_alias_index(addr_t->is_ptr());
3143       assert ((uint)alias_idx < new_index_end, "wrong alias index");
3144       Node *mem = find_inst_mem(n->in(MemNode::Memory), alias_idx, orig_phis);
3145       if (_compile->failing()) {
3146         return;
3147       }
3148       if (mem != n->in(MemNode::Memory)) {
3149         // We delay the memory edge update since we need old one in
3150         // MergeMem code below when instances memory slices are separated.
3151         set_map(n, mem);
3152       }
3153       if (n->is_Load()) {
3154         continue;  // don't push users
3155       } else if (n->is_LoadStore()) {
3156         // get the memory projection
3157         for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3158           Node *use = n->fast_out(i);
3159           if (use->Opcode() == Op_SCMemProj) {
3160             n = use;
3161             break;
3162           }
3163         }
3164         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
3165       }
3166     }
3167     // push user on appropriate worklist
3168     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3169       Node *use = n->fast_out(i);
3170       if (use->is_Phi() || use->is_ClearArray()) {
3171         memnode_worklist.append_if_missing(use);
3172       } else if (use->is_Mem() && use->in(MemNode::Memory) == n) {
3173         if (use->Opcode() == Op_StoreCM) // Ignore cardmark stores
3174           continue;
3175         memnode_worklist.append_if_missing(use);
3176       } else if (use->is_MemBar()) {
3177         if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
3178           memnode_worklist.append_if_missing(use);
3179         }
3180 #ifdef ASSERT
3181       } else if(use->is_Mem()) {
3182         assert(use->in(MemNode::Memory) != n, "EA: missing memory path");
3183       } else if (use->is_MergeMem()) {
3184         assert(_mergemem_worklist.contains(use->as_MergeMem()), "EA: missing MergeMem node in the worklist");
3185       } else if (use->Opcode() == Op_EncodeISOArray) {
3186         if (use->in(MemNode::Memory) == n || use->in(3) == n) {
3187           // EncodeISOArray overwrites destination array
3188           memnode_worklist.append_if_missing(use);
3189         }
3190       } else {
3191         uint op = use->Opcode();
3192         if (!(op == Op_StoreCM ||
3193               (op == Op_CallLeaf && use->as_CallLeaf()->_name != NULL &&
3194                strcmp(use->as_CallLeaf()->_name, "g1_wb_pre") == 0) ||
3195               op == Op_AryEq || op == Op_StrComp ||
3196               op == Op_StrEquals || op == Op_StrIndexOf)) {
3197           n->dump();
3198           use->dump();
3199           assert(false, "EA: missing memory path");
3200         }
3201 #endif
3202       }
3203     }
3204   }
3205 
3206   //  Phase 3:  Process MergeMem nodes from mergemem_worklist.
3207   //            Walk each memory slice moving the first node encountered of each
3208   //            instance type to the the input corresponding to its alias index.
3209   uint length = _mergemem_worklist.length();
3210   for( uint next = 0; next < length; ++next ) {
3211     MergeMemNode* nmm = _mergemem_worklist.at(next);
3212     assert(!visited.test_set(nmm->_idx), "should not be visited before");
3213     // Note: we don't want to use MergeMemStream here because we only want to
3214     // scan inputs which exist at the start, not ones we add during processing.
3215     // Note 2: MergeMem may already contains instance memory slices added
3216     // during find_inst_mem() call when memory nodes were processed above.
3217     igvn->hash_delete(nmm);
3218     uint nslices = MIN2(nmm->req(), new_index_start);
3219     for (uint i = Compile::AliasIdxRaw+1; i < nslices; i++) {
3220       Node* mem = nmm->in(i);
3221       Node* cur = NULL;
3222       if (mem == NULL || mem->is_top())
3223         continue;
3224       // First, update mergemem by moving memory nodes to corresponding slices
3225       // if their type became more precise since this mergemem was created.
3226       while (mem->is_Mem()) {
3227         const Type *at = igvn->type(mem->in(MemNode::Address));
3228         if (at != Type::TOP) {
3229           assert (at->isa_ptr() != NULL, "pointer type required.");
3230           uint idx = (uint)_compile->get_alias_index(at->is_ptr());
3231           if (idx == i) {
3232             if (cur == NULL)
3233               cur = mem;
3234           } else {
3235             if (idx >= nmm->req() || nmm->is_empty_memory(nmm->in(idx))) {
3236               nmm->set_memory_at(idx, mem);
3237             }
3238           }
3239         }
3240         mem = mem->in(MemNode::Memory);
3241       }
3242       nmm->set_memory_at(i, (cur != NULL) ? cur : mem);
3243       // Find any instance of the current type if we haven't encountered
3244       // already a memory slice of the instance along the memory chain.
3245       for (uint ni = new_index_start; ni < new_index_end; ni++) {
3246         if((uint)_compile->get_general_index(ni) == i) {
3247           Node *m = (ni >= nmm->req()) ? nmm->empty_memory() : nmm->in(ni);
3248           if (nmm->is_empty_memory(m)) {
3249             Node* result = find_inst_mem(mem, ni, orig_phis);
3250             if (_compile->failing()) {
3251               return;
3252             }
3253             nmm->set_memory_at(ni, result);
3254           }
3255         }
3256       }
3257     }
3258     // Find the rest of instances values
3259     for (uint ni = new_index_start; ni < new_index_end; ni++) {
3260       const TypeOopPtr *tinst = _compile->get_adr_type(ni)->isa_oopptr();
3261       Node* result = step_through_mergemem(nmm, ni, tinst);
3262       if (result == nmm->base_memory()) {
3263         // Didn't find instance memory, search through general slice recursively.
3264         result = nmm->memory_at(_compile->get_general_index(ni));
3265         result = find_inst_mem(result, ni, orig_phis);
3266         if (_compile->failing()) {
3267           return;
3268         }
3269         nmm->set_memory_at(ni, result);
3270       }
3271     }
3272     igvn->hash_insert(nmm);
3273     record_for_optimizer(nmm);
3274   }
3275 
3276   //  Phase 4:  Update the inputs of non-instance memory Phis and
3277   //            the Memory input of memnodes
3278   // First update the inputs of any non-instance Phi's from
3279   // which we split out an instance Phi.  Note we don't have
3280   // to recursively process Phi's encounted on the input memory
3281   // chains as is done in split_memory_phi() since they  will
3282   // also be processed here.
3283   for (int j = 0; j < orig_phis.length(); j++) {
3284     PhiNode *phi = orig_phis.at(j);
3285     int alias_idx = _compile->get_alias_index(phi->adr_type());
3286     igvn->hash_delete(phi);
3287     for (uint i = 1; i < phi->req(); i++) {
3288       Node *mem = phi->in(i);
3289       Node *new_mem = find_inst_mem(mem, alias_idx, orig_phis);
3290       if (_compile->failing()) {
3291         return;
3292       }
3293       if (mem != new_mem) {
3294         phi->set_req(i, new_mem);
3295       }
3296     }
3297     igvn->hash_insert(phi);
3298     record_for_optimizer(phi);
3299   }
3300 
3301   // Update the memory inputs of MemNodes with the value we computed
3302   // in Phase 2 and move stores memory users to corresponding memory slices.
3303   // Disable memory split verification code until the fix for 6984348.
3304   // Currently it produces false negative results since it does not cover all cases.
3305 #if 0 // ifdef ASSERT
3306   visited.Reset();
3307   Node_Stack old_mems(arena, _compile->unique() >> 2);
3308 #endif
3309   for (uint i = 0; i < ideal_nodes.size(); i++) {
3310     Node*    n = ideal_nodes.at(i);
3311     Node* nmem = get_map(n->_idx);
3312     assert(nmem != NULL, "sanity");
3313     if (n->is_Mem()) {
3314 #if 0 // ifdef ASSERT
3315       Node* old_mem = n->in(MemNode::Memory);
3316       if (!visited.test_set(old_mem->_idx)) {
3317         old_mems.push(old_mem, old_mem->outcnt());
3318       }
3319 #endif
3320       assert(n->in(MemNode::Memory) != nmem, "sanity");
3321       if (!n->is_Load()) {
3322         // Move memory users of a store first.
3323         move_inst_mem(n, orig_phis);
3324       }
3325       // Now update memory input
3326       igvn->hash_delete(n);
3327       n->set_req(MemNode::Memory, nmem);
3328       igvn->hash_insert(n);
3329       record_for_optimizer(n);
3330     } else {
3331       assert(n->is_Allocate() || n->is_CheckCastPP() ||
3332              n->is_AddP() || n->is_Phi(), "unknown node used for set_map()");
3333     }
3334   }
3335 #if 0 // ifdef ASSERT
3336   // Verify that memory was split correctly
3337   while (old_mems.is_nonempty()) {
3338     Node* old_mem = old_mems.node();
3339     uint  old_cnt = old_mems.index();
3340     old_mems.pop();
3341     assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
3342   }
3343 #endif
3344 }
3345 
3346 #ifndef PRODUCT
3347 static const char *node_type_names[] = {
3348   "UnknownType",
3349   "JavaObject",
3350   "LocalVar",
3351   "Field",
3352   "Arraycopy"
3353 };
3354 
3355 static const char *esc_names[] = {
3356   "UnknownEscape",
3357   "NoEscape",
3358   "ArgEscape",
3359   "GlobalEscape"
3360 };
3361 
3362 void PointsToNode::dump(bool print_state) const {
3363   NodeType nt = node_type();
3364   tty->print("%s ", node_type_names[(int) nt]);
3365   if (print_state) {
3366     EscapeState es = escape_state();
3367     EscapeState fields_es = fields_escape_state();
3368     tty->print("%s(%s) ", esc_names[(int)es], esc_names[(int)fields_es]);
3369     if (nt == PointsToNode::JavaObject && !this->scalar_replaceable())
3370       tty->print("NSR ");
3371   }
3372   if (is_Field()) {
3373     FieldNode* f = (FieldNode*)this;
3374     if (f->is_oop())
3375       tty->print("oop ");
3376     if (f->offset() > 0)
3377       tty->print("+%d ", f->offset());
3378     tty->print("(");
3379     for (BaseIterator i(f); i.has_next(); i.next()) {
3380       PointsToNode* b = i.get();
3381       tty->print(" %d%s", b->idx(),(b->is_JavaObject() ? "P" : ""));
3382     }
3383     tty->print(" )");
3384   }
3385   tty->print("[");
3386   for (EdgeIterator i(this); i.has_next(); i.next()) {
3387     PointsToNode* e = i.get();
3388     tty->print(" %d%s%s", e->idx(),(e->is_JavaObject() ? "P" : (e->is_Field() ? "F" : "")), e->is_Arraycopy() ? "cp" : "");
3389   }
3390   tty->print(" [");
3391   for (UseIterator i(this); i.has_next(); i.next()) {
3392     PointsToNode* u = i.get();
3393     bool is_base = false;
3394     if (PointsToNode::is_base_use(u)) {
3395       is_base = true;
3396       u = PointsToNode::get_use_node(u)->as_Field();
3397     }
3398     tty->print(" %d%s%s", u->idx(), is_base ? "b" : "", u->is_Arraycopy() ? "cp" : "");
3399   }
3400   tty->print(" ]]  ");
3401   if (_node == NULL)
3402     tty->print_cr("<null>");
3403   else
3404     _node->dump();
3405 }
3406 
3407 void ConnectionGraph::dump(GrowableArray<PointsToNode*>& ptnodes_worklist) {
3408   bool first = true;
3409   int ptnodes_length = ptnodes_worklist.length();
3410   for (int i = 0; i < ptnodes_length; i++) {
3411     PointsToNode *ptn = ptnodes_worklist.at(i);
3412     if (ptn == NULL || !ptn->is_JavaObject())
3413       continue;
3414     PointsToNode::EscapeState es = ptn->escape_state();
3415     if ((es != PointsToNode::NoEscape) && !Verbose) {
3416       continue;
3417     }
3418     Node* n = ptn->ideal_node();
3419     if (n->is_Allocate() || (n->is_CallStaticJava() &&
3420                              n->as_CallStaticJava()->is_boxing_method())) {
3421       if (first) {
3422         tty->cr();
3423         tty->print("======== Connection graph for ");
3424         _compile->method()->print_short_name();
3425         tty->cr();
3426         first = false;
3427       }
3428       ptn->dump();
3429       // Print all locals and fields which reference this allocation
3430       for (UseIterator j(ptn); j.has_next(); j.next()) {
3431         PointsToNode* use = j.get();
3432         if (use->is_LocalVar()) {
3433           use->dump(Verbose);
3434         } else if (Verbose) {
3435           use->dump();
3436         }
3437       }
3438       tty->cr();
3439     }
3440   }
3441 }
3442 #endif