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